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WO2025031897A1 - Hydraulic unit for a drive train of a motor vehicle - Google Patents

Hydraulic unit for a drive train of a motor vehicle Download PDF

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Publication number
WO2025031897A1
WO2025031897A1 PCT/EP2024/071610 EP2024071610W WO2025031897A1 WO 2025031897 A1 WO2025031897 A1 WO 2025031897A1 EP 2024071610 W EP2024071610 W EP 2024071610W WO 2025031897 A1 WO2025031897 A1 WO 2025031897A1
Authority
WO
WIPO (PCT)
Prior art keywords
actuator
hydraulic
actuation
hydraulic unit
base plate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/EP2024/071610
Other languages
French (fr)
Inventor
Manuel Fischer
Patrick Weber
Andreas Schorn
Christian Sperber
Stefan Krauser
Patrick Gegner
Markus Krug
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Valeo Embrayages SAS
Original Assignee
Valeo Embrayages SAS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Valeo Embrayages SAS filed Critical Valeo Embrayages SAS
Publication of WO2025031897A1 publication Critical patent/WO2025031897A1/en
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/0003—Arrangement or mounting of elements of the control apparatus, e.g. valve assemblies or snapfittings of valves; Arrangements of the control unit on or in the transmission gearbox
    • F16H61/0009—Hydraulic control units for transmission control, e.g. assembly of valve plates or valve units
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/0021—Generation or control of line pressure
    • F16H61/0025—Supply of control fluid; Pumps therefor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H63/00—Control outputs from the control unit to change-speed- or reversing-gearings for conveying rotary motion or to other devices than the final output mechanism
    • F16H63/40—Control outputs from the control unit to change-speed- or reversing-gearings for conveying rotary motion or to other devices than the final output mechanism comprising signals other than signals for actuating the final output mechanisms
    • F16H63/48—Signals to a parking brake or parking lock; Control of parking locks or brakes being part of the transmission
    • F16H63/483—Circuits for controlling engagement of parking locks or brakes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/0021—Generation or control of line pressure
    • F16H2061/0037—Generation or control of line pressure characterised by controlled fluid supply to lubrication circuits of the gearing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/26—Generation or transmission of movements for final actuating mechanisms
    • F16H61/28—Generation or transmission of movements for final actuating mechanisms with at least one movement of the final actuating mechanism being caused by a non-mechanical force, e.g. power-assisted
    • F16H61/30—Hydraulic or pneumatic motors or related fluid control means therefor
    • F16H2061/308—Modular hydraulic shift units, i.e. preassembled actuator units for select and shift movements adapted for being mounted on transmission casing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/0021—Generation or control of line pressure
    • F16H61/0025—Supply of control fluid; Pumps therefor
    • F16H61/0031—Supply of control fluid; Pumps therefor using auxiliary pumps, e.g. pump driven by a different power source than the engine
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H63/00—Control outputs from the control unit to change-speed- or reversing-gearings for conveying rotary motion or to other devices than the final output mechanism
    • F16H63/02—Final output mechanisms therefor; Actuating means for the final output mechanisms
    • F16H63/30—Constructional features of the final output mechanisms
    • F16H63/34—Locking or disabling mechanisms
    • F16H63/3416—Parking lock mechanisms or brakes in the transmission
    • F16H63/3483—Parking lock mechanisms or brakes in the transmission with hydraulic actuating means

Definitions

  • Hydraulic unit for a drive train of a motor vehicle
  • the invention concerns a hydraulic unit, in particular for the drive train of a motor vehicle, with a hydraulic pump, a supply outlet and an actuation outlet.
  • a single hydraulic unit for both lubrication or cooling of components, and also for hydraulic actuation of actuators.
  • the hydraulic unit delivers hydraulic fluid via the supply outlet to a transmission and/or an electric motor for the purpose of cooling and/or lubrication
  • the hydraulic unit delivers the hydraulic fluid via the actuation outlet to a hydraulic actuator. This may actuate a clutch, a transmission actuator or any other component which is actuated by a hydraulic pressure.
  • DE 10 2018 102 690 A1 discloses a cover for a transmission on which various functional components, e.g. a pump, are arranged and enabled as required.
  • the object of the invention is to develop a hydraulic unit of the kind mentioned at the outset such that a high integration density is possible.
  • a base plate which preferably comprises plastic and which integrates a housing for the hydraulic pump, wherein at least one actuator which is connected to the actuation outlet is arranged on the base plate, and wherein the base plate is configured as a transmission cover with a sealing face which is designed to come into contact with a transmission casing.
  • the invention is based on the concept of integrating in the base plate all components which are necessary so that firstly a lubricating or cooling flow can be (at least substantially) continuously provided via the supply outlet, and when required a pressurized fluid flow, via which an actuator can be actuated, can be output via the actuation outlet (in these phases, the cooling flow is briefly interrupted). Integration in the base plate firstly allows fluid channels to be formed inside the base plate so that no external lines are necessary, and secondly the components are arranged compactly partly on the transmission side and partly outside the transmission.
  • Integrated in the base plate here means that the corresponding component is either formed integrally with the base plate or is attached directly to another component which is integrated in the base plate, or is directly attached e.g. firmly bolted thereto.
  • the base plate preferably consists of plastic.
  • other materials are possible, e.g. aluminum or aluminum alloys.
  • a second actuation outlet is provided so that in addition to the first actuator, a second actuator can be actuated.
  • the actuator can be locked in two actuation positions and has a freely lying actuation valve which can be brought into engagement with an actuating element on the transmission side.
  • Such an actuator may be used in particular for switching a dog clutch, via which for example an electric motor can be coupled to or decoupled from the drive train.
  • the actuator may have two guide housings which are bolted to the base plate, between which the actuation valve lies freely. This allows the actuator to be preassembled. When the actuator is then mounted on the base plate, it is automatically connected to corresponding fluid channels, which minimizes the overall installation complexity.
  • the actuator may be a short-stroke actuator, in particular a concentric clutch actuator, the actuation direction of which is parallel to the extent plane of the base plate.
  • Such an actuator may switch friction clutches in a compact construction.
  • the actuator may have an actuator housing with multiple fastening openings, by means of which the actuator can be supported on the transmission. In this way, the reaction moment of the actuator can be received directly by the clutch to be actuated, so that the base plate is not or is only slightly loaded.
  • a housing of the hydraulic pump and/or electric plug connector may be integrated in the base plate, which avoids the cost of separate mounting of these components.
  • a filter for hydraulic fluid is integrated directly in the base plate so that the hydraulic pump can draw in fluid directly from the interior of the transmission casing. No further mounting steps are necessary as the base plate with hydraulic pump and filter is mounted on the transmission casing.
  • the filter may have a filter housing on the base plate side and a filter cover connected to the filter housing by bolting, welding or clipping.
  • the filter cover formed separately from the filter housing, facilitates mounting of a filter element inside the filter housing.
  • the supply outlet and the actuation outlet may be connected to an outlet of the hydraulic pump, wherein a switch valve is arranged between the supply outlet and the pump outlet.
  • the hydraulic pump is always operated in the same rotational direction and the operating mode is changed by means of the switch valve. If hydraulic fluid is to be conducted to a lubricating or cooling system via the supply outlet, the switch valve is open so that the volume flow delivered by the pump is output through the supply outlet.
  • the delivery pressure of the pump which is substantially equal to the pressure at the supply outlet, is present at the actuation outlet. This pressure is however comparatively low, so that the actuator connected to the actuation outlet is not actuated, irrespective of its concrete design.
  • the switch valve When the actuator is to be switched from a first position to a second position, the switch valve is switched into a closed position so that the supply outlet is closed. The entire delivery stream of the pump is therefore conducted to the actuation outlet in order to switch the actuator from one position to another.
  • a transmission can be switched or a clutch closed.
  • the pump rotation speed may be temporarily increased.
  • the hydraulic unit has a high energy efficiency since the hydraulic fluid can be delivered at the supply outlet without losses; there is no need for a valve to actively maintain a specific state, and there are no components in the flow path which would lead to increased flow resistance.
  • the actuation outlet may be connected directly to the pump outlet, giving a highly economic construction.
  • a second actuation outlet is provided, wherein a second switch valve is arranged between the second actuation outlet and the pump outlet. This allows two actuators to be controlled via the actuation side of the pump without requiring great additional structural complexity.
  • the second switch valve is preferably a normally closed valve so that the hydraulic unit normally works in the same way as before for the first actuation outlet. Only when the second actuator is to be actuated is the second switch valve opened, so that a hydraulic fluid can be delivered via the second actuation outlet.
  • a pressure sensor is assigned to the second actuation outlet so that a precise feedback is available on a suitable time at which the second switch valve can be closed again.
  • an overpressure valve is provided which connects the downstream side of the pump to the downstream side of the first switch valve, or more precisely, a point between the pump outlet and the switch valve is connected to the downstream side of the first switch valve.
  • the overpressure valve prevents an excessively high pressure building up on the delivery side of the pump in a state in which the two switch valves are closed, which could damage one of the switch valves.
  • a suction connection is provided which can be connected to a storage container. This leads to a small volume of the hydraulic unit and great flexibility, since the storage container may be designed depending on external conditions.
  • the hydraulic pump may be of the single-flow type, allowing a simple construction. In principle however, multi-flow pumps may also be used.
  • the hydraulic pump is preferably a displacement pump, in particular a gerotor pump, a vane pump or a gear pump, which all have a high efficiency with low structural volume.
  • the hydraulic unit may be part of an assembly, wherein a lubricant line is connected to the supply outlet and an actuator connected to the actuation outlet, wherein the actuator can be locked in at least one actuation position. Since the actuator is lockable, it can be locked in a position set by the actuation pressure, so that then the pump is operated with a delivery pressure which is set with regard to other requirements, e.g. for the lubricating system.
  • the delivery pressure of the pump need not be matched to the actuator in order for example to hold this in its actuation position: this is ensured by the locking, e.g. by a latching magnet.
  • the actuator can be locked in both actuation positions, so that after the actuator has been set to a desired position, it can be locked there and remain there irrespective of the delivery pressure.
  • the actuator connected to the second actuation outlet may be a short-stroke actuator, in particular a concentric clutch actuator, which may be used to close and open a friction clutch.
  • a pressure accumulator is provided which in particular is arranged between the second switch valve and the actuator. This compensates for any pressure loss over the second switch valve, so that the second actuator remains closed for comparatively long periods.
  • the hydraulic pump may be reversibly operable and have two pump connections which act as suction and as pressure connections depending on rotation direction.
  • the hydraulic unit has at least one suction intake for drawing in hydraulic fluid, wherein, starting from the suction intake, a suction line portion extends to each of the pump connections, and a check valve blocking in the direction towards the suction intake is arranged in each of the suction line portions.
  • a first pressure line extends to a lubricant connection of the hydraulic unit, wherein a check valve blocking in the direction towards the pump connection is arranged in the first pressure line.
  • a second pressure line leads to an actuator connection of the hydraulic unit, wherein the second pressure line is free of valves.
  • the construction of the hydraulic unit is particularly simple and cost-effective.
  • Another advantage is that, in an operating mode of the hydraulic unit in which the second pump connection of the reversible hydraulic pump acts as a suction connection, a negative pressure is generated at the actuator connection. A reaction time of a connected actuator is thus improved. In particular, a resistance caused by the inertia of the hydraulic fluid is reduced. Furthermore, the negative pressure ensures that air in the line can escape via the reversible hydraulic pump, and thus simultaneously purges the pressure line.
  • the reversible hydraulic pump is for example a rotary vane pump, a gerotor pump or a gear pump.
  • Such pumps have a simple construction and can operate equally efficiently in both conveying directions.
  • the reversible hydraulic pump has for example an electric motor. This has the advantage that the delivery rate of hydraulic fluid, required for the respective object of transmission lubrication or clutch actuation, can be set by simply controlling the speed of the electric motor.
  • the hydraulic unit may be part of an assembly which also comprises a clutch actuator connected to the actuator connection of the hydraulic unit.
  • the hydraulic unit can be used both for transmission lubrication and for clutch actuation.
  • the clutch actuator is a single-acting hydraulic piston which works against a return spring.
  • the return spring additionally contributes to a negative pressure generated at the actuator connection in a reversible pump, so that the clutch actuator resets quickly after actuation and a connected clutch therefore opens quickly.
  • a locking bolt is provided which interacts with the hydraulic piston.
  • the locking bolt is used to lock the clutch actuator in an actuating position or in an opening position.
  • the clutch actuator can then also be held in an actuating position when the second pump connection acts as a suction connection, and a negative pressure prevails at the actuator connection.
  • the clutch actuator can likewise be reliably held in an open position.
  • a solenoid may be assigned to the locking bolt.
  • an actuating mechanism of the locking bolt can be produced in a simple manner.
  • electronic control of the locking bolt is possible.
  • the assembly comprises for example a dog clutch which can be actuated by the clutch actuator.
  • a dog clutch has a simple construction and is particularly robust. However, other types of clutches are also possible.
  • An oil cooler is preferably arranged in the pressure line which extends to the lubricant connection. This improves the cooling effect of the hydraulic oil.
  • a bypass for the oil cooler wherein an overpressure or pressure-limiting valve blocking in the direction towards the pump connection is arranged in the bypass.
  • a pressure acting in the oil cooler can be limited by means of the additional bypass, since the overpressure or pressurelimiting valve in the bypass opens at sufficiently high pressure, and hydraulic oil reaches the lubricant connection additionally via the bypass.
  • Figure 1 shows a plan view of a hydraulic unit according to the invention
  • Figure 2 shows a side view of the hydraulic unit from figure 1 ;
  • Figure 3 shows a view from below of the hydraulic unit from figure 1 ;
  • Figure 4 shows a perspective plan view of the hydraulic unit from figure 1 ;
  • Figure 5 shows a further perspective view of the hydraulic unit from figure 1 ;
  • Figure 6 shows a perspective view from below of the hydraulic unit from figure 1 ;
  • Figure 7 shows a perspective view of a hydraulic unit according to the invention together with a transmission
  • Figure 8 shows a further perspective view of the assembly of hydraulic unit and transmission from figure 7;
  • Figure 9 shows schematically a first embodiment of the hydraulic unit from figures 1 to 6
  • Figure 10 shows schematically a second embodiment of the hydraulic unit from figures 1 to 6;
  • Figure 11 shows schematically a third embodiment of the hydraulic unit from figures 1 to 6;
  • Figure 12 shows the embodiment from figure 11 , wherein the hydraulic unit is in a first operating mode
  • Figure 13 shows the embodiment from figure 11 , wherein the hydraulic unit is in a second operating mode.
  • FIGS 1 to 6 show a hydraulic unit 10 according to the invention which is configured as a unit integrated on a base plate 12.
  • the base plate 12 serves to close an opening in a transmission casing 14 (see figure 2), here illustrated schematically. Accordingly, the base plate forms a transmission cover.
  • the base plate 12 is substantially flat and made of plastic. It has a sealing face 16 which is intended to come into contact with the transmission casing 14. In the exemplary embodiment shown, the sealing face 16 has a peripheral seal 18.
  • the base plate may also consist of aluminum or aluminum alloy.
  • the base plate 12 has multiple fastening openings 20 by means of which it can be bolted to the transmission casing 14.
  • a hydraulic pump 22, of which only a pump housing 24 can be seen in figures 1 to 6, is integrated into the base plate 12 and is closed by a cover 26.
  • the pump housing 24 is here formed integrally with the base plate 12, while the cover 26 is bolted to the pump housing 24.
  • the hydraulic pump 22 is a pump driven by an electric motor, e.g. a rotary vane pump, a gear pump or a gerotor pump.
  • an electric motor e.g. a rotary vane pump, a gear pump or a gerotor pump.
  • the hydraulic pump 22 draws in hydraulic fluid through a filter 28 which is integrated in the base plate 12.
  • a switch valve 30 is arranged on the base plate 12 and serves for switching between a supply to one or more actuators 32, 34 (to be explained below) and the fluid output to a supply outlet 36 during operation of the hydraulic unit 10.
  • the supply outlet 36 serves to deliver a comparatively large fluid stream under a comparatively low pressure to a transmission or other components which must be cooled and/or lubricated. These may be bearing points, friction clutches or electric motors.
  • the actuator 32 has an actuation valve 40 which is guided movably between two positions in two guide housings 42.
  • the two guide housings 42 are mounted on the base plate, e.g. by screwing, so that internal pistons can be supplied with fluid.
  • the actuation valve can thereby be moved between its two end positions.
  • the base plate 12 also integrates a solenoid 44 with which the actuation valve 40 can be locked in its respective end position.
  • the actuator 34 is here a concentric clutch actuator, i.e. a short-stroke actuator, which is mounted such that its actuation direction extends parallel to the plane containing the base plate 12.
  • the base plate 12 integrates a switch valve 50 via which the actuator 34 can be actuated.
  • the actuator 34 has on the outside multiple fastening openings 35 via which it can be supported on the transmission.
  • a pressure sensor 52 which monitors the pressure on closure of the clutch assigned to the actuator 34, is also integrated.
  • the hydraulic unit 10 is provided with various plug connectors 60 which can be connected to complementary plug connectors of a wiring harness, by means of which the various components of the hydraulic unit 10 can be actuated.
  • Figures 7 and 8 show schematically the hydraulic unit 10 in cooperation with various components which are arranged in the interior of the transmission of the transmission casing 14.
  • an actuator 34 can be seen, which cooperates with a clutch (not shown here in detail).
  • an actuating element 70 can be seen, which engages in the actuation valve 40 of the actuator 32.
  • Figure 9 shows a hydraulic unit 110 which may be integrated in the base plate of the embodiment of figures 1 to 6.
  • the hydraulic unit 110 has a hydraulic pump 112 and a drive device 114 for the hydraulic pump 112.
  • the hydraulic pump may be configured as a displacement pump. Particularly suitable designs are gear pumps, vane pumps or gerotor pumps.
  • the drive device 114 is preferably an electric motor.
  • the hydraulic unit 110 has a suction connection 116 which is connected to a storage container 118. This is a pump sump inside the transmission casing.
  • a filter 120 is arranged between the suction connection 116 and the suction intake of the hydraulic pump 112.
  • the hydraulic unit 110 has a supply outlet 122, corresponding to the supply outlet 36 known from figures 1 to 6, and an actuation outlet 124.
  • the supply outlet 122 serves for a lubricating a transmission (not shown further here) or a clutch (not shown here) or an electric motor (not shown here).
  • a cooler 126 and a bypass 128 may be provided before the hydraulic fluid conveyed by the hydraulic pump 112 reaches the lubrication points or clutch.
  • the supply outlet serves to provide a volume flow of hydraulic fluid for long periods.
  • the volume flow is always required for lubrication when components rotate.
  • the volume flow is always required for cooling when waste heat is produced. In both cases, the volume flow is required for a period ranging from several seconds up to a continuous volume flow.
  • the actuation outlet 124 serves to provide a volume flow for actuating an actuator 150 provided on the base plate. This corresponds to the actuator 32 of the embodiment in figures 1 to 6. In contrast to the volume flow provided at the supply outlet 122, the volume flow at the actuation outlet 124 is required only for a very short period.
  • the supply outlet 122 and the activation outlet 124 are together connected to a pressure outlet 130 of the hydraulic pump 112.
  • a switch valve 134 is arranged downstream of a branch point 132 in the line leading to the supply outlet 122.
  • the switch valve 134 may be configured as a magnet-operated slide valve.
  • connection between the pressure outlet 130 of the hydraulic pump 112 and the actuation outlet 124 contains no valves or other active components.
  • the actuation outlet 124 is thus connected directly to the pressure outlet 130.
  • the actuator 150 is a parking lock actuator 150 which can be switched or actuated from a state with activated parking lock into a state with deactivated parking lock, and vice versa.
  • the parking lock actuator 150 is pressed into a first actuation position by a spring 152.
  • the parking lock actuator 150 can be locked in this actuation position.
  • a magnet-operated latching device 154 may be used.
  • the parking lock actuator When a sufficiently high pressure is present at the actuation outlet 124, the parking lock actuator is moved from the first actuation position to a second actuation position.
  • the parking lock actuator 150 can also be locked in the second actuation position.
  • a second magnet-operated latching device 156 may be used.
  • position sensors may be provided which are not shown here for greater clarity.
  • a second actuator 150' (or if necessary also a third, fourth etc.) may be actuated in parallel with the parking lock actuator 150.
  • a switch valve 153 is assigned thereto.
  • the hydraulic unit 110 may be operated in two modes.
  • a so-called supply mode the hydraulic pump 112 serves to convey hydraulic fluid from the supply outlet 122 to the lubrication or cooling points in the drive train of the motor vehicle.
  • the switch valve 134 is opened.
  • the delivery pressure is usually so low that the spring 152 holds the parking lock actuator 150 in the first actuation position.
  • the parking lock actuator 150 can be locked in the first actuation position by means of the first latching device 154, so that a brief increase in the delivery pressure of the hydraulic pump 112 does not cause the first parking lock actuator 150 to be switched into the second actuation position.
  • the switch valve 134 is closed and the first latching device 154 is opened. At the same time, the rotation speed of the hydraulic pump 112 is increased so that the delivery pressure rises. This switches the parking lock actuator into the second actuation position. It can be locked in this actuation position by the second latching device 156.
  • a pressure-limiting valve 157 is arranged between the two fluid channels outside the supply outlet 122 and actuation outlet 124.
  • the latching device 156 When the parking lock actuator 150 is to be returned to the first actuation position, the latching device 156 is opened so that the spring 152 returns the parking lock actuator 150 to the first actuation position. The hydraulic fluid displaced thereby is discharged via the supply outlet 122. When the parking lock actuator 150 is in the first actuation position, it is locked there by the latching device 154.
  • the position of the actuator 150 can be monitored by means of suitable position sensors.
  • Figure 10 shows a hydraulic unit according to a second embodiment, which may also be integrated in the base plate of the embodiment of figures 1 to 6.
  • the same reference signs are used for the components known from the embodiment in figure 9, and, in this respect, reference is made to the first embodiment.
  • an actuator 150 is connected to the actuation outlet 124 and can be locked in both its actuation positions by means of two latching devices 154, 156.
  • the actuator 150 is here configured as an actuating cylinder for actuating a dog clutch. With respect to the type and manner of its actuation by the hydraulic unit 110, however, there are no structural differences from the actuator 150 of the first embodiment.
  • a second actuator 151 which is a short-stroke actuator 151 , in particular a concentric clutch actuator 151 , is connected to the second actuation outlet 124'. It serves to actuate a friction clutch from an open position into a closed position, and corresponds to the actuator 34 of the embodiment of figures 1 to 6.
  • a second switch valve 160 is provided which is arranged between the branch leading to the first actuation outlet 124 and the second actuation outlet 124'. It can open and close the connection between the pressure outlet 132 and the second actuation outlet 124'.
  • the second switch valve 160 may be a magnet-operated ball valve.
  • a pressure sensor 162 which is connected to a controller (not shown here), is arranged between the second switch valve 160 and the second actuation outlet 124'.
  • an overpressure valve 164 is arranged inside the hydraulic unit 110 and connects the hydraulic branch between the two switch valves 134, 160, i.e. downstream of the pressure outlet 130, to the downstream side of the first switch valve 134.
  • the second switch valve 160 When the second actuator 151 is to be actuated, the second switch valve 160 is opened and the first switch valve 134 closed. In this way, the conveyed hydraulic oil reaches the second actuator 151 which closes its assigned clutch.
  • the first actuator here remains in its current actuation position because of the latching devices 154, 156.
  • the closure of the clutch can be monitored via the pressure detected by the pressure sensor 162.
  • the second switch valve 160 can be closed again.
  • the second actuator 151 is “blocked” so the clutch remains closed.
  • the supply outlet 122 and the actuation outlet 124 can again be supplied with hydraulic fluid in the desired fashion.
  • a pressure store 166 is arranged in the hydraulic branch "after" the second actuation outlet, which guarantees that when the second switch valve 160 is closed, the pressure is maintained and the clutch is held in a closed state, even if the switch valve 160 has a slight leakage If the pressure sensor 162 detects a pressure below a predefined threshold value, the second switch valve 160 can be opened briefly so that the pressure in the branch of the second actuator 151 is increased again.
  • the overpressure valve 164 guarantees that the pressure in the branch between the two switch valves 134, 160 cannot become excessively high, e.g. if the hydraulic pump 112 is working when the switch valves 134, 160 are closed and the first actuator 150 is locked.
  • Figure 11 shows a third embodiment of the hydraulic unit which may be integrated in the base plate of the embodiment of figures 1 to 6.
  • FIG 11 shows a hydraulic unit 212 which serves for hydraulic clutch actuation and transmission lubrication.
  • the hydraulic unit 212 can be operated in a first operating mode for clutch actuation and in a second operating mode for transmission lubrication, as will be described further in the following.
  • hydraulic fluid can be conveyed to a lubricant connection 214 or to an actuator connection 216.
  • the lubricant connection 214 corresponds to the supply connection 36 of the embodiment in figures 1 to 6.
  • the hydraulic unit 212 has a reversible hydraulic pump 218 having two pump connections 220, 222.
  • the pump connections 220, 222 can act as a suction connection and a pressure connection depending on the direction of rotation of the reversible hydraulic pump 218.
  • An electric motor 224 which can operate the reversible hydraulic pump 218, in both operating directions is assigned to the hydraulic pump 218.
  • the reversible hydraulic pump 218 is for example a rotary vane pump, a gerotor pump or a gear pump.
  • the hydraulic unit 212 has a suction intake 226 for the intake of hydraulic fluid.
  • a filter 227 which corresponds to the filter 28 of the embodiment in figures 1 to 6, is provided at the suction intake 226.
  • a storage container 228 which contains hydraulic fluid is provided, wherein the suction intake 226 is arranged in the storage container 228.
  • the storage container is configured as a pump sump inside the transmission.
  • suction line portion 230, 232 extends to each of the pump connections 220, 222.
  • a first pressure line 234 extends to the lubricant connection 214 of the hydraulic unit 212.
  • a second pressure line 236 extends to the actuator connection 216 of the hydraulic unit 212.
  • a check valve 238, 240 (or generally an overpressure or pressure-limiting valve), which blocks in the direction towards the suction intake 226, is arranged in each of the suction line portions 230, 232.
  • Another check valve 242 (or generally an overpressure or pressure-limiting valve), which blocks in the direction towards the pump connection 220, is arranged in the pressure line 234 running from the first pump connection 220 to the lubricant connection 214.
  • a clutch actuator 244 is connected to the actuator connection 216. This corresponds to the actuator 32 of the embodiment in figures 1 to 6.
  • the clutch actuator 244 is a single-acting hydraulic piston 246 which works against a return spring 247.
  • the hydraulic piston 246 is linearly guided in a housing 249.
  • a clutch 248 of an assembly 210 of the hydraulic unit and clutch can be actuated, wherein in the exemplary embodiment the clutch is a dog clutch.
  • the hydraulic piston 246 is operatively connected to a clutch sleeve 250 of the clutch 248.
  • the hydraulic piston 246 can be locked by means of a locking bolt 252 which interacts with the hydraulic piston 246.
  • the locking bolt 252 engages in radial notches 254, 256 in the hydraulic piston 246.
  • the notches 254, 256 are arranged in such a way that, when the locking bolt 252 engages in the first notch 254, the hydraulic piston 246 is held in an actuating position in which the clutch 248 is closed, and when the locking bolt 252 engages in the second notch 256, the hydraulic piston 246 is held in an open position in which the clutch 248 is open.
  • a solenoid 258 is assigned to the locking bolt 252.
  • the locking bolt 252 can be lifted to release the hydraulic piston 246.
  • an oil cooler 262 is arranged in the pressure line 234 which extends to the lubricant connection 214.
  • the bypass 264 makes it possible to convey a greater volume flow rate of hydraulic fluid to the lubricant connection 214 than would be possible by means of the oil cooler 262.
  • the check valve 266 prevents hydraulic fluid from returning from the outlet of the oil cooler 262 to the pump connection 220.
  • Figure 12 illustrates the assembly 210 in which the hydraulic unit 212 is operated in a first operating mode for clutch actuation.
  • a direction of rotation of the reversible hydraulic pump 218 is illustrated by an arrow 260.
  • the first pump connection 220 acts as a suction connection
  • the second pump connection 222 acts as a pressure connection
  • the reversible hydraulic pump 218 takes in hydraulic fluid via the first suction line portion 230 and conveys this fluid to the actuator connection 216 so that a fluid pressure at the actuator connection 216 increases.
  • the check valve 240 which blocks in the direction towards the suction intake 226, in the second suction line portion 232 prevents hydraulic fluid from being conveyed directly back into the storage container 228.
  • FIG. 13 illustrates the assembly 210 in which the hydraulic unit 212 is operated in a second operating mode for transmission lubrication and/or transmission cooling.
  • the second pump connection 222 acts as a suction connection
  • the first pump connection 220 acts as a pressure connection
  • the reversible hydraulic pump 218 takes in hydraulic fluid via the second suction line portion 232 and conveys this fluid to the lubricant connection 214, from where the hydraulic fluid reaches a transmission to be lubricated.
  • the check valve 238, which blocks in the direction towards the suction intake 226, in the first suction line portion 230 prevents hydraulic fluid from being conveyed directly back into the storage container 228.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Hydraulic Clutches, Magnetic Clutches, Fluid Clutches, And Fluid Joints (AREA)

Abstract

The invention concerns a hydraulic unit (10), in particular for the drive train of a motor vehicle, with a hydraulic pump (22), a supply outlet (34) and an actuation outlet, wherein a base plate (12) is provided which preferably comprises plastic and which integrates a housing (24) for the hydraulic pump (22), wherein at least one actuator (32, 34) which is connected to the actuation outlet is arranged on the base plate (12), and wherein the base plate (12) is configured as a transmission cover with a sealing face (16) which is designed to come into contact with a transmission casing (14).

Description

Hydraulic unit for a drive train of a motor vehicle
The invention concerns a hydraulic unit, in particular for the drive train of a motor vehicle, with a hydraulic pump, a supply outlet and an actuation outlet.
It is known to use a single hydraulic unit for both lubrication or cooling of components, and also for hydraulic actuation of actuators. In a first operating state, the hydraulic unit delivers hydraulic fluid via the supply outlet to a transmission and/or an electric motor for the purpose of cooling and/or lubrication, and in a second operating state the hydraulic unit delivers the hydraulic fluid via the actuation outlet to a hydraulic actuator. This may actuate a clutch, a transmission actuator or any other component which is actuated by a hydraulic pressure.
An example of a hydraulic unit of the type cited initially can be found in DE 10 2018 007 459 A1.
DE 10 2018 102 690 A1 discloses a cover for a transmission on which various functional components, e.g. a pump, are arranged and enabled as required.
The object of the invention is to develop a hydraulic unit of the kind mentioned at the outset such that a high integration density is possible.
To achieve this object, according to the invention, in a hydraulic unit of the type cited initially, a base plate is provided which preferably comprises plastic and which integrates a housing for the hydraulic pump, wherein at least one actuator which is connected to the actuation outlet is arranged on the base plate, and wherein the base plate is configured as a transmission cover with a sealing face which is designed to come into contact with a transmission casing. The invention is based on the concept of integrating in the base plate all components which are necessary so that firstly a lubricating or cooling flow can be (at least substantially) continuously provided via the supply outlet, and when required a pressurized fluid flow, via which an actuator can be actuated, can be output via the actuation outlet (in these phases, the cooling flow is briefly interrupted). Integration in the base plate firstly allows fluid channels to be formed inside the base plate so that no external lines are necessary, and secondly the components are arranged compactly partly on the transmission side and partly outside the transmission.
"Integrated in the base plate" here means that the corresponding component is either formed integrally with the base plate or is attached directly to another component which is integrated in the base plate, or is directly attached e.g. firmly bolted thereto.
The base plate preferably consists of plastic. Alternatively, other materials are possible, e.g. aluminum or aluminum alloys.
According to one embodiment of the invention, a second actuation outlet is provided so that in addition to the first actuator, a second actuator can be actuated.
The actuator can be locked in two actuation positions and has a freely lying actuation valve which can be brought into engagement with an actuating element on the transmission side. Such an actuator may be used in particular for switching a dog clutch, via which for example an electric motor can be coupled to or decoupled from the drive train.
The actuator may have two guide housings which are bolted to the base plate, between which the actuation valve lies freely. This allows the actuator to be preassembled. When the actuator is then mounted on the base plate, it is automatically connected to corresponding fluid channels, which minimizes the overall installation complexity.
The actuator may be a short-stroke actuator, in particular a concentric clutch actuator, the actuation direction of which is parallel to the extent plane of the base plate. Such an actuator may switch friction clutches in a compact construction.
The actuator may have an actuator housing with multiple fastening openings, by means of which the actuator can be supported on the transmission. In this way, the reaction moment of the actuator can be received directly by the clutch to be actuated, so that the base plate is not or is only slightly loaded. A housing of the hydraulic pump and/or electric plug connector may be integrated in the base plate, which avoids the cost of separate mounting of these components.
According to one embodiment of the invention, a filter for hydraulic fluid is integrated directly in the base plate so that the hydraulic pump can draw in fluid directly from the interior of the transmission casing. No further mounting steps are necessary as the base plate with hydraulic pump and filter is mounted on the transmission casing.
The filter may have a filter housing on the base plate side and a filter cover connected to the filter housing by bolting, welding or clipping. The filter cover, formed separately from the filter housing, facilitates mounting of a filter element inside the filter housing.
Further aspects of the invention are explained below.
The supply outlet and the actuation outlet may be connected to an outlet of the hydraulic pump, wherein a switch valve is arranged between the supply outlet and the pump outlet. The hydraulic pump is always operated in the same rotational direction and the operating mode is changed by means of the switch valve. If hydraulic fluid is to be conducted to a lubricating or cooling system via the supply outlet, the switch valve is open so that the volume flow delivered by the pump is output through the supply outlet. The delivery pressure of the pump, which is substantially equal to the pressure at the supply outlet, is present at the actuation outlet. This pressure is however comparatively low, so that the actuator connected to the actuation outlet is not actuated, irrespective of its concrete design. When the actuator is to be switched from a first position to a second position, the switch valve is switched into a closed position so that the supply outlet is closed. The entire delivery stream of the pump is therefore conducted to the actuation outlet in order to switch the actuator from one position to another. Thus e.g. a transmission can be switched or a clutch closed. Depending on the pressure necessary for this, the pump rotation speed may be temporarily increased.
As a whole, the hydraulic unit has a high energy efficiency since the hydraulic fluid can be delivered at the supply outlet without losses; there is no need for a valve to actively maintain a specific state, and there are no components in the flow path which would lead to increased flow resistance.
According to one embodiment of the invention, the actuation outlet may be connected directly to the pump outlet, giving a highly economic construction.
According to an embodiment of the invention, a second actuation outlet is provided, wherein a second switch valve is arranged between the second actuation outlet and the pump outlet. This allows two actuators to be controlled via the actuation side of the pump without requiring great additional structural complexity.
The second switch valve is preferably a normally closed valve so that the hydraulic unit normally works in the same way as before for the first actuation outlet. Only when the second actuator is to be actuated is the second switch valve opened, so that a hydraulic fluid can be delivered via the second actuation outlet.
Preferably, a pressure sensor is assigned to the second actuation outlet so that a precise feedback is available on a suitable time at which the second switch valve can be closed again.
If a second switch valve is present, preferably an overpressure valve is provided which connects the downstream side of the pump to the downstream side of the first switch valve, or more precisely, a point between the pump outlet and the switch valve is connected to the downstream side of the first switch valve. The overpressure valve prevents an excessively high pressure building up on the delivery side of the pump in a state in which the two switch valves are closed, which could damage one of the switch valves.
According to an embodiment, a suction connection is provided which can be connected to a storage container. This leads to a small volume of the hydraulic unit and great flexibility, since the storage container may be designed depending on external conditions.
The hydraulic pump may be of the single-flow type, allowing a simple construction. In principle however, multi-flow pumps may also be used.
The hydraulic pump is preferably a displacement pump, in particular a gerotor pump, a vane pump or a gear pump, which all have a high efficiency with low structural volume. The hydraulic unit may be part of an assembly, wherein a lubricant line is connected to the supply outlet and an actuator connected to the actuation outlet, wherein the actuator can be locked in at least one actuation position. Since the actuator is lockable, it can be locked in a position set by the actuation pressure, so that then the pump is operated with a delivery pressure which is set with regard to other requirements, e.g. for the lubricating system. The delivery pressure of the pump need not be matched to the actuator in order for example to hold this in its actuation position: this is ensured by the locking, e.g. by a latching magnet.
Preferably, the actuator can be locked in both actuation positions, so that after the actuator has been set to a desired position, it can be locked there and remain there irrespective of the delivery pressure.
According to an embodiment, the actuator connected to the second actuation outlet may be a short-stroke actuator, in particular a concentric clutch actuator, which may be used to close and open a friction clutch.
According to a refinement of the invention, a pressure accumulator is provided which in particular is arranged between the second switch valve and the actuator. This compensates for any pressure loss over the second switch valve, so that the second actuator remains closed for comparatively long periods.
The hydraulic pump may be reversibly operable and have two pump connections which act as suction and as pressure connections depending on rotation direction. The hydraulic unit has at least one suction intake for drawing in hydraulic fluid, wherein, starting from the suction intake, a suction line portion extends to each of the pump connections, and a check valve blocking in the direction towards the suction intake is arranged in each of the suction line portions. Starting from a first pump connection, a first pressure line extends to a lubricant connection of the hydraulic unit, wherein a check valve blocking in the direction towards the pump connection is arranged in the first pressure line. Starting from a second pump connection, a second pressure line leads to an actuator connection of the hydraulic unit, wherein the second pressure line is free of valves.
As a result of the fact that the second pressure line is free of valves, the construction of the hydraulic unit is particularly simple and cost-effective. Another advantage is that, in an operating mode of the hydraulic unit in which the second pump connection of the reversible hydraulic pump acts as a suction connection, a negative pressure is generated at the actuator connection. A reaction time of a connected actuator is thus improved. In particular, a resistance caused by the inertia of the hydraulic fluid is reduced. Furthermore, the negative pressure ensures that air in the line can escape via the reversible hydraulic pump, and thus simultaneously purges the pressure line.
The reversible hydraulic pump is for example a rotary vane pump, a gerotor pump or a gear pump. Such pumps have a simple construction and can operate equally efficiently in both conveying directions.
The reversible hydraulic pump has for example an electric motor. This has the advantage that the delivery rate of hydraulic fluid, required for the respective object of transmission lubrication or clutch actuation, can be set by simply controlling the speed of the electric motor.
The hydraulic unit may be part of an assembly which also comprises a clutch actuator connected to the actuator connection of the hydraulic unit. In an assembly of this type, the hydraulic unit can be used both for transmission lubrication and for clutch actuation.
According to one embodiment, the clutch actuator is a single-acting hydraulic piston which works against a return spring. The return spring additionally contributes to a negative pressure generated at the actuator connection in a reversible pump, so that the clutch actuator resets quickly after actuation and a connected clutch therefore opens quickly.
Preferably, a locking bolt is provided which interacts with the hydraulic piston. The locking bolt is used to lock the clutch actuator in an actuating position or in an opening position. As a result, the clutch actuator can then also be held in an actuating position when the second pump connection acts as a suction connection, and a negative pressure prevails at the actuator connection. The clutch actuator can likewise be reliably held in an open position.
A solenoid may be assigned to the locking bolt. By means of the solenoid, an actuating mechanism of the locking bolt can be produced in a simple manner. In particular, electronic control of the locking bolt is possible. The assembly comprises for example a dog clutch which can be actuated by the clutch actuator. A dog clutch has a simple construction and is particularly robust. However, other types of clutches are also possible.
An oil cooler is preferably arranged in the pressure line which extends to the lubricant connection. This improves the cooling effect of the hydraulic oil.
According to one embodiment, there is a bypass for the oil cooler, wherein an overpressure or pressure-limiting valve blocking in the direction towards the pump connection is arranged in the bypass. A pressure acting in the oil cooler can be limited by means of the additional bypass, since the overpressure or pressurelimiting valve in the bypass opens at sufficiently high pressure, and hydraulic oil reaches the lubricant connection additionally via the bypass.
The invention will be described below on the basis of two embodiments which are shown in the appended drawings. In said drawings:
Figure 1 shows a plan view of a hydraulic unit according to the invention;
Figure 2 shows a side view of the hydraulic unit from figure 1 ;
Figure 3 shows a view from below of the hydraulic unit from figure 1 ;
Figure 4 shows a perspective plan view of the hydraulic unit from figure 1 ;
Figure 5 shows a further perspective view of the hydraulic unit from figure 1 ;
Figure 6 shows a perspective view from below of the hydraulic unit from figure 1 ;
Figure 7 shows a perspective view of a hydraulic unit according to the invention together with a transmission;
Figure 8 shows a further perspective view of the assembly of hydraulic unit and transmission from figure 7;
Figure 9 shows schematically a first embodiment of the hydraulic unit from figures 1 to 6; Figure 10 shows schematically a second embodiment of the hydraulic unit from figures 1 to 6;
Figure 11 shows schematically a third embodiment of the hydraulic unit from figures 1 to 6;
Figure 12 shows the embodiment from figure 11 , wherein the hydraulic unit is in a first operating mode;
Figure 13 shows the embodiment from figure 11 , wherein the hydraulic unit is in a second operating mode.
Figures 1 to 6 show a hydraulic unit 10 according to the invention which is configured as a unit integrated on a base plate 12.
The base plate 12 serves to close an opening in a transmission casing 14 (see figure 2), here illustrated schematically. Accordingly, the base plate forms a transmission cover.
The base plate 12 is substantially flat and made of plastic. It has a sealing face 16 which is intended to come into contact with the transmission casing 14. In the exemplary embodiment shown, the sealing face 16 has a peripheral seal 18.
Alternatively to plastic as a material, the base plate may also consist of aluminum or aluminum alloy.
Along its edge, the base plate 12 has multiple fastening openings 20 by means of which it can be bolted to the transmission casing 14.
A hydraulic pump 22, of which only a pump housing 24 can be seen in figures 1 to 6, is integrated into the base plate 12 and is closed by a cover 26.
The pump housing 24 is here formed integrally with the base plate 12, while the cover 26 is bolted to the pump housing 24.
The hydraulic pump 22 is a pump driven by an electric motor, e.g. a rotary vane pump, a gear pump or a gerotor pump.
The hydraulic pump 22 draws in hydraulic fluid through a filter 28 which is integrated in the base plate 12. A switch valve 30 is arranged on the base plate 12 and serves for switching between a supply to one or more actuators 32, 34 (to be explained below) and the fluid output to a supply outlet 36 during operation of the hydraulic unit 10.
The supply outlet 36 serves to deliver a comparatively large fluid stream under a comparatively low pressure to a transmission or other components which must be cooled and/or lubricated. These may be bearing points, friction clutches or electric motors.
The actuator 32 has an actuation valve 40 which is guided movably between two positions in two guide housings 42. The two guide housings 42 are mounted on the base plate, e.g. by screwing, so that internal pistons can be supplied with fluid. The actuation valve can thereby be moved between its two end positions.
The base plate 12 also integrates a solenoid 44 with which the actuation valve 40 can be locked in its respective end position.
The actuator 34 is here a concentric clutch actuator, i.e. a short-stroke actuator, which is mounted such that its actuation direction extends parallel to the plane containing the base plate 12.
Furthermore, the base plate 12 integrates a switch valve 50 via which the actuator 34 can be actuated.
The actuator 34 has on the outside multiple fastening openings 35 via which it can be supported on the transmission.
A pressure sensor 52, which monitors the pressure on closure of the clutch assigned to the actuator 34, is also integrated.
Finally, the hydraulic unit 10 is provided with various plug connectors 60 which can be connected to complementary plug connectors of a wiring harness, by means of which the various components of the hydraulic unit 10 can be actuated.
Figures 7 and 8 show schematically the hydraulic unit 10 in cooperation with various components which are arranged in the interior of the transmission of the transmission casing 14. Firstly, an actuator 34 can be seen, which cooperates with a clutch (not shown here in detail).. Secondly, an actuating element 70 can be seen, which engages in the actuation valve 40 of the actuator 32.
Figure 9 shows a hydraulic unit 110 which may be integrated in the base plate of the embodiment of figures 1 to 6.
The hydraulic unit 110 has a hydraulic pump 112 and a drive device 114 for the hydraulic pump 112.
The hydraulic pump may be configured as a displacement pump. Particularly suitable designs are gear pumps, vane pumps or gerotor pumps. The drive device 114 is preferably an electric motor.
The hydraulic unit 110 has a suction connection 116 which is connected to a storage container 118. This is a pump sump inside the transmission casing.
A filter 120 is arranged between the suction connection 116 and the suction intake of the hydraulic pump 112.
The hydraulic unit 110 has a supply outlet 122, corresponding to the supply outlet 36 known from figures 1 to 6, and an actuation outlet 124. The supply outlet 122 serves for a lubricating a transmission (not shown further here) or a clutch (not shown here) or an electric motor (not shown here). Outside the hydraulic unit 110 therefore, a cooler 126 and a bypass 128 may be provided before the hydraulic fluid conveyed by the hydraulic pump 112 reaches the lubrication points or clutch. These components are here marked S and K.
In general terms, the supply outlet serves to provide a volume flow of hydraulic fluid for long periods. The volume flow is always required for lubrication when components rotate. The volume flow is always required for cooling when waste heat is produced. In both cases, the volume flow is required for a period ranging from several seconds up to a continuous volume flow.
The actuation outlet 124 serves to provide a volume flow for actuating an actuator 150 provided on the base plate. This corresponds to the actuator 32 of the embodiment in figures 1 to 6. In contrast to the volume flow provided at the supply outlet 122, the volume flow at the actuation outlet 124 is required only for a very short period. The supply outlet 122 and the activation outlet 124 are together connected to a pressure outlet 130 of the hydraulic pump 112. A switch valve 134 is arranged downstream of a branch point 132 in the line leading to the supply outlet 122.
The switch valve 134 may be configured as a magnet-operated slide valve.
It serves to open or close the connection between the pressure outlet 130 of the hydraulic pump 112 and the supply outlet 122 of the hydraulic unit 110.
The connection between the pressure outlet 130 of the hydraulic pump 112 and the actuation outlet 124 contains no valves or other active components. The actuation outlet 124 is thus connected directly to the pressure outlet 130.
In the exemplary embodiment shown here, the actuator 150 is a parking lock actuator 150 which can be switched or actuated from a state with activated parking lock into a state with deactivated parking lock, and vice versa.
The parking lock actuator 150 is pressed into a first actuation position by a spring 152. The parking lock actuator 150 can be locked in this actuation position. For this, a magnet-operated latching device 154 may be used.
When a sufficiently high pressure is present at the actuation outlet 124, the parking lock actuator is moved from the first actuation position to a second actuation position. The parking lock actuator 150 can also be locked in the second actuation position. For this, a second magnet-operated latching device 156 may be used.
In order to monitor the positions of the parking lock actuator 150, position sensors may be provided which are not shown here for greater clarity.
A second actuator 150' (or if necessary also a third, fourth etc.) may be actuated in parallel with the parking lock actuator 150. A switch valve 153 is assigned thereto.
The hydraulic unit 110 may be operated in two modes. In a so-called supply mode, the hydraulic pump 112 serves to convey hydraulic fluid from the supply outlet 122 to the lubrication or cooling points in the drive train of the motor vehicle. To this end, the switch valve 134 is opened. In this state, the delivery pressure is usually so low that the spring 152 holds the parking lock actuator 150 in the first actuation position. In addition, the parking lock actuator 150 can be locked in the first actuation position by means of the first latching device 154, so that a brief increase in the delivery pressure of the hydraulic pump 112 does not cause the first parking lock actuator 150 to be switched into the second actuation position.
If the parking lock actuator 150 is to be switched into the second actuation position, the switch valve 134 is closed and the first latching device 154 is opened. At the same time, the rotation speed of the hydraulic pump 112 is increased so that the delivery pressure rises. This switches the parking lock actuator into the second actuation position. It can be locked in this actuation position by the second latching device 156.
Then the rotation speed of the hydraulic pump 112 can be reduced again and the switch valve 134 opened again. Thus the lubrication or cooling system is again supplied with hydraulic fluid. The brief interruption in the supply to the lubrication or cooling system during switching of the parking lock actuator 150 does not adversely affect the lubrication and cooling.
A pressure-limiting valve 157 is arranged between the two fluid channels outside the supply outlet 122 and actuation outlet 124.
When the parking lock actuator 150 is to be returned to the first actuation position, the latching device 156 is opened so that the spring 152 returns the parking lock actuator 150 to the first actuation position. The hydraulic fluid displaced thereby is discharged via the supply outlet 122. When the parking lock actuator 150 is in the first actuation position, it is locked there by the latching device 154.
The position of the actuator 150 can be monitored by means of suitable position sensors.
It is also possible to operate the hydraulic pump with a higher volume flow and discharge this completely to the supply outlet 122 when the actuator 150 is locked, insofar as this is suitable in a specific operating mode. Figure 10 shows a hydraulic unit according to a second embodiment, which may also be integrated in the base plate of the embodiment of figures 1 to 6. The same reference signs are used for the components known from the embodiment in figure 9, and, in this respect, reference is made to the first embodiment.
The difference between the designs in figures 9 and 10 is that with the design of figure 10, two actuation outlets 124, 124' are provided on the hydraulic unit 110. These serve to actuate different actuators.
As in the first embodiment, an actuator 150 is connected to the actuation outlet 124 and can be locked in both its actuation positions by means of two latching devices 154, 156. In contrast to the first embodiment, the actuator 150 is here configured as an actuating cylinder for actuating a dog clutch. With respect to the type and manner of its actuation by the hydraulic unit 110, however, there are no structural differences from the actuator 150 of the first embodiment.
A second actuator 151 , which is a short-stroke actuator 151 , in particular a concentric clutch actuator 151 , is connected to the second actuation outlet 124'. It serves to actuate a friction clutch from an open position into a closed position, and corresponds to the actuator 34 of the embodiment of figures 1 to 6.
Inside the hydraulic unit 110, a second switch valve 160 is provided which is arranged between the branch leading to the first actuation outlet 124 and the second actuation outlet 124'. It can open and close the connection between the pressure outlet 132 and the second actuation outlet 124'.
The second switch valve 160 may be a magnet-operated ball valve.
A pressure sensor 162, which is connected to a controller (not shown here), is arranged between the second switch valve 160 and the second actuation outlet 124'.
Finally, an overpressure valve 164 is arranged inside the hydraulic unit 110 and connects the hydraulic branch between the two switch valves 134, 160, i.e. downstream of the pressure outlet 130, to the downstream side of the first switch valve 134.
Assuming that the second switch valve 160 is closed, the lubrication and cooling system connected to the supply outlet 122, and the actuator 150 connected to the first actuation outlet 124 (and any further actuators 150'), are operated or activated in the same fashion as in the first embodiment.
When the second actuator 151 is to be actuated, the second switch valve 160 is opened and the first switch valve 134 closed. In this way, the conveyed hydraulic oil reaches the second actuator 151 which closes its assigned clutch. The first actuator here remains in its current actuation position because of the latching devices 154, 156.
The closure of the clutch can be monitored via the pressure detected by the pressure sensor 162.
When the clutch is closed, the second switch valve 160 can be closed again. Thus the second actuator 151 is "blocked" so the clutch remains closed. In this state, the supply outlet 122 and the actuation outlet 124 can again be supplied with hydraulic fluid in the desired fashion.
A pressure store 166 is arranged in the hydraulic branch "after" the second actuation outlet, which guarantees that when the second switch valve 160 is closed, the pressure is maintained and the clutch is held in a closed state, even if the switch valve 160 has a slight leakage If the pressure sensor 162 detects a pressure below a predefined threshold value, the second switch valve 160 can be opened briefly so that the pressure in the branch of the second actuator 151 is increased again.
The overpressure valve 164 guarantees that the pressure in the branch between the two switch valves 134, 160 cannot become excessively high, e.g. if the hydraulic pump 112 is working when the switch valves 134, 160 are closed and the first actuator 150 is locked.
In principle, it is also possible to actuate the two actuators 150, 151 simultaneously.
Figure 11 shows a third embodiment of the hydraulic unit which may be integrated in the base plate of the embodiment of figures 1 to 6.
Figure 11 shows a hydraulic unit 212 which serves for hydraulic clutch actuation and transmission lubrication. For this purpose, the hydraulic unit 212 can be operated in a first operating mode for clutch actuation and in a second operating mode for transmission lubrication, as will be described further in the following.
In particular, by means of the hydraulic unit 212, hydraulic fluid can be conveyed to a lubricant connection 214 or to an actuator connection 216. The lubricant connection 214 corresponds to the supply connection 36 of the embodiment in figures 1 to 6.
The hydraulic unit 212 has a reversible hydraulic pump 218 having two pump connections 220, 222. The pump connections 220, 222 can act as a suction connection and a pressure connection depending on the direction of rotation of the reversible hydraulic pump 218.
An electric motor 224, which can operate the reversible hydraulic pump 218, in both operating directions is assigned to the hydraulic pump 218.
The reversible hydraulic pump 218 is for example a rotary vane pump, a gerotor pump or a gear pump.
The hydraulic unit 212 has a suction intake 226 for the intake of hydraulic fluid.
A filter 227, which corresponds to the filter 28 of the embodiment in figures 1 to 6, is provided at the suction intake 226.
In the exemplary embodiment, a storage container 228 which contains hydraulic fluid is provided, wherein the suction intake 226 is arranged in the storage container 228. The storage container is configured as a pump sump inside the transmission.
Starting from the suction intake 226, in each case one suction line portion 230, 232 extends to each of the pump connections 220, 222.
Starting from a first pump connection 220, a first pressure line 234 extends to the lubricant connection 214 of the hydraulic unit 212.
Starting from a second pump connection 222, a second pressure line 236 extends to the actuator connection 216 of the hydraulic unit 212. A check valve 238, 240 (or generally an overpressure or pressure-limiting valve), which blocks in the direction towards the suction intake 226, is arranged in each of the suction line portions 230, 232.
Another check valve 242 (or generally an overpressure or pressure-limiting valve), which blocks in the direction towards the pump connection 220, is arranged in the pressure line 234 running from the first pump connection 220 to the lubricant connection 214.
However, the pressure line 236 leading from the second pump connection 222 to the actuator connection 216 is free of valves.
In the exemplary embodiment shown, a clutch actuator 244 is connected to the actuator connection 216. This corresponds to the actuator 32 of the embodiment in figures 1 to 6.
The clutch actuator 244 is a single-acting hydraulic piston 246 which works against a return spring 247.
The hydraulic piston 246 is linearly guided in a housing 249.
By means of the clutch actuator 244, a clutch 248 of an assembly 210 of the hydraulic unit and clutch can be actuated, wherein in the exemplary embodiment the clutch is a dog clutch. For this purpose, the hydraulic piston 246 is operatively connected to a clutch sleeve 250 of the clutch 248.
The hydraulic piston 246 can be locked by means of a locking bolt 252 which interacts with the hydraulic piston 246.
For the purpose of locking, the locking bolt 252 engages in radial notches 254, 256 in the hydraulic piston 246.
The notches 254, 256 are arranged in such a way that, when the locking bolt 252 engages in the first notch 254, the hydraulic piston 246 is held in an actuating position in which the clutch 248 is closed, and when the locking bolt 252 engages in the second notch 256, the hydraulic piston 246 is held in an open position in which the clutch 248 is open.
A solenoid 258 is assigned to the locking bolt 252. When the solenoid 258 is energized, the locking bolt 252 can be lifted to release the hydraulic piston 246. In order to simultaneously bring about particularly efficient cooling during the lubrication of the transmission, an oil cooler 262 is arranged in the pressure line 234 which extends to the lubricant connection 214.
In addition, there is a bypass 264 to the oil cooler 262, a check valve 266 which blocks in the direction towards the pump connection 220 being arranged in the bypass 264.
The bypass 264 makes it possible to convey a greater volume flow rate of hydraulic fluid to the lubricant connection 214 than would be possible by means of the oil cooler 262.
In this case, the check valve 266 prevents hydraulic fluid from returning from the outlet of the oil cooler 262 to the pump connection 220.
Figure 12 illustrates the assembly 210 in which the hydraulic unit 212 is operated in a first operating mode for clutch actuation.
A direction of rotation of the reversible hydraulic pump 218 is illustrated by an arrow 260.
In this case, the first pump connection 220 acts as a suction connection, and the second pump connection 222 acts as a pressure connection.
In figure 12, the fluid-conveying lines are shown in bold by way of illustration.
The reversible hydraulic pump 218 takes in hydraulic fluid via the first suction line portion 230 and conveys this fluid to the actuator connection 216 so that a fluid pressure at the actuator connection 216 increases.
The check valve 240, which blocks in the direction towards the suction intake 226, in the second suction line portion 232 prevents hydraulic fluid from being conveyed directly back into the storage container 228.
As soon as the locking bolt 252 releases the hydraulic piston 246, the hydraulic piston, which is shown in its open position in figure 10, moves into the actuating position (see figure 13) and closes the clutch 248. Figure 13 illustrates the assembly 210 in which the hydraulic unit 212 is operated in a second operating mode for transmission lubrication and/or transmission cooling.
In this case, the second pump connection 222 acts as a suction connection, and the first pump connection 220 acts as a pressure connection.
In figure 13, the fluid-conveying lines are also shown in bold by way of illustration.
The reversible hydraulic pump 218 takes in hydraulic fluid via the second suction line portion 232 and conveys this fluid to the lubricant connection 214, from where the hydraulic fluid reaches a transmission to be lubricated.
In this case, the check valve 238, which blocks in the direction towards the suction intake 226, in the first suction line portion 230 prevents hydraulic fluid from being conveyed directly back into the storage container 228.
At the same time, as a result of the fact that there are no valves in the second pressure line 236, hydraulic fluid is taken in from the pressure line 236, and therefore a negative pressure is produced at the actuator connection 216. A resistance when resetting the hydraulic piston 246 is thus reduced, as a result of which the reaction speed increases, and the pressure line 236 and the hydraulic piston 246 are purged by means of the reversible hydraulic pump 260.
This means that, as soon as the locking bolt 252 releases the hydraulic piston 246 held in the actuating position, said piston can be moved into its open position particularly quickly by means of the return force of the return spring 247. In this manner, an opening behaviour of the clutch 248 is improved.
The invention is not restricted to the embodiments and designs shown. All features of the embodiments of figures 9 to 13 may be arranged on the base plate of figures 1 to 6 individually or in combination, as long as this lies in the sense of the object to be achieved: that of increasing the integration density on the base plate and at the same time achieving a variable functionality of the hydraulic unit.

Claims

Patent claims
1. A hydraulic unit (10), in particular for the drive train of a motor vehicle, with a hydraulic pump (22), a supply outlet (34) and an actuation outlet, wherein a base plate (12) is provided which preferably comprises plastic and which integrates a housing (24) for the hydraulic pump (22), wherein at least one actuator (32, 34) which is connected to the actuation outlet is arranged on the base plate (12), and wherein the base plate (12) is configured as a transmission cover with a sealing face (16) which is designed to come into contact with a transmission casing (14).
2. The hydraulic unit as claimed in claim 1 , wherein a second actuation outlet is provided.
3. The hydraulic unit as claimed in any of the preceding claims, wherein the actuator (32) can be locked in two actuation positions and has a freely lying actuation valve (40) which can be brought into engagement with an actuating element (70) on the transmission side.
4. The hydraulic unit as claimed in any of the preceding claims, wherein the actuator has two guide housings (42) which are bolted to the base plate (12) and between which the actuation valve (40) lies freely.
5. The hydraulic unit as claimed in any of the preceding claims, wherein the actuator is a short-stroke actuator (34), in particular a concentric clutch actuator, the actuation direction of which is parallel to the extent plane of the base plate (12).
6. The hydraulic unit as claimed in claim 5, wherein the actuator has an actuator housing with multiple fastening openings (35), by means of which the actuator (34) can be supported on the transmission side.
7. The hydraulic unit as claimed in any of the preceding claims, wherein a housing (24) of the hydraulic pump (22) is integrated in the base plate (12).
8. The hydraulic unit as claimed in any of the preceding claims, wherein electric plug connectors (60) are integrated in the base plate (12).
9. The hydraulic unit as claimed in any of the preceding claims, wherein a filter (28) for hydraulic fluid is integrated in the base plate (12).
10. The hydraulic unit as claimed in claim 9, wherein the filter (28) has a filter housing on the base plate side and a filter cover connected to the filter housing by bolting, welding or clipping.
PCT/EP2024/071610 2023-08-08 2024-07-30 Hydraulic unit for a drive train of a motor vehicle Pending WO2025031897A1 (en)

Applications Claiming Priority (2)

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DE102023121096.3 2023-08-08
DE102023121096.3A DE102023121096A1 (en) 2023-08-08 2023-08-08 Hydraulic unit for a drive train of a motor vehicle

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020032093A1 (en) * 2000-09-08 2002-03-14 Mark Kopec Transmission control apparatus
US20020062714A1 (en) * 1999-05-11 2002-05-30 Roland Albert Electronic-hydraulic control device for transmissions of vehicles, preferably of motor vehicles
DE102018102690A1 (en) 2018-02-07 2019-08-08 Schaeffler Technologies AG & Co. KG Hydraulic actuators
DE102018007459A1 (en) 2018-09-21 2020-03-26 Fte Automotive Gmbh Device for hydraulic clutch actuation and gear lubrication for a motor vehicle
DE102019212079A1 (en) * 2019-08-13 2021-02-18 Zf Friedrichshafen Ag Hydraulic actuator module for attachment to a motor vehicle transmission
US20210381593A1 (en) * 2018-10-26 2021-12-09 Schaeffler Technologies AG & Co. KG Actuator for a motor vehicle

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Publication number Priority date Publication date Assignee Title
WO2018118130A1 (en) * 2016-12-22 2018-06-28 Eaton Corporation System, method, and apparatus for operating a high efficiency, high output transmission
DE102018122310A1 (en) * 2018-09-12 2020-03-12 Fte Automotive Gmbh Pump unit for providing a hydraulic pressure for actuating an actuator in the drive train of a motor vehicle, in particular a clutch or transmission actuator
CN113212105B (en) * 2021-06-16 2022-03-18 广州小鹏汽车科技有限公司 Thermal management system, control method thereof and vehicle

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020062714A1 (en) * 1999-05-11 2002-05-30 Roland Albert Electronic-hydraulic control device for transmissions of vehicles, preferably of motor vehicles
US20020032093A1 (en) * 2000-09-08 2002-03-14 Mark Kopec Transmission control apparatus
DE102018102690A1 (en) 2018-02-07 2019-08-08 Schaeffler Technologies AG & Co. KG Hydraulic actuators
DE102018007459A1 (en) 2018-09-21 2020-03-26 Fte Automotive Gmbh Device for hydraulic clutch actuation and gear lubrication for a motor vehicle
US20210381593A1 (en) * 2018-10-26 2021-12-09 Schaeffler Technologies AG & Co. KG Actuator for a motor vehicle
DE102019212079A1 (en) * 2019-08-13 2021-02-18 Zf Friedrichshafen Ag Hydraulic actuator module for attachment to a motor vehicle transmission

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