EP2880327A1

EP2880327A1 - Coolant conveyor for a wet friction clutch

Info

Publication number: EP2880327A1
Application number: EP13753558.9A
Authority: EP
Inventors: Michael KÜHNLE; Toros GÜLLÜK; Thorsten Krause; Christine BÜDENBENDER; Peter Wahl
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2012-08-01
Filing date: 2013-07-30
Publication date: 2015-06-10
Also published as: WO2014019581A1; DE112013003783A5; DE102013214820A1

Abstract

The invention relates to a coolant conveyor (1) for a wet friction clutch (2), comprising at least one disk (3) with at least one guiding structure (4, 5, 6) for transporting the coolant in the axial direction (8) and/or in the radial direction (9). It is possible, with said claimed coolant conveyor and/or wet friction clutch with a coolant conveyor, to increase the cooling efficiency of the coolant in the wet chamber of the wet friction clutch, or to reduce the amount of coolant conveyed.

Description

Coolant conveyor for a wet friction clutch

The invention relates to a coolant delivery device for a wet friction clutch, which is particularly suitable for use as a starting clutch in small vehicles.

In currently known wet friction clutches no conveyor structures are provided. Rather, the oil used is pressed against the pressure in the wet room and the shears in the region of the lamellar basket. The cooling potential of a friction clutch is not fully utilized.

On this basis, the present invention has the object, at least partially overcome the known from the prior art disadvantages. The object is solved by the features of the independent claims. Advantageous developments are the subject of the dependent claims.

The invention relates to a coolant delivery device for a wet friction clutch, comprising at least one disc with at least one guide structure for conveying coolant in the axial direction and / or radial direction.

The cooling liquid conveying device accomplishes a promotion of the cooling liquid in a wet space of a wet friction clutch, whereby the pump pressure to be applied for conveying the cooling liquid can be reduced. A cooling liquid is usually a mineral oil, silicone oil or another, in particular synthetic, liquid which does not have a corrosive effect on the materials used and has a suitable heat capacity and viscosity. By reducing the pressure, the internal friction in the coolant is also reduced, so that the coolant with a higher usable heat capacity can be introduced into the wet space. The coolant delivery device comprises a disc, which is preferably rotationally symmetrical. In particular, the disc limits a portion of the wet space volume in the wet friction clutch. The disk does not have to be flat, but can have projections and recesses, for example in the manner of a shaped sheet metal part. In this case, the disk comprises a guide structure which at least supports the conveying of a cooling liquid in the wet space of a friction clutch. The conveying direction can be in the axial direction, that is perpendicular to the disc, or in the radial direction Direction, that is along a radius of the disc supported. In this case, the cooling liquid does not have to follow exactly these directions, but only be conveyed over a period of time in said direction or have a motion vector component in this direction. The lead structures can be formed, inter alia, by a rough surface or by exposed pins or rivets on a surface of the disc. A rough surface can be achieved, for example, by a raw casting surface. Particularly preferably, such a mold is designed explicitly rough, so that a significantly rougher surface is formed than is desirable for conventional applications. In particular, the roughness of the surface is adapted to the viscosity of the coolant used. The roughness should be as large as possible to ensure a maximum entrainment effect, that is, no limits are set to the top or extreme roughness is then again synonymous with blade effect or blade structures.

In particular, the cooling liquid conveying device is passively operable; that is, at a relative speed between the cooling liquid and the cooling liquid conveying device, the cooling liquid is conveyed through the guide structure in the axial and / or radial direction. In this case, for example, the cooling liquid conveying device can stand and rotate the cooling liquid in a ring, because it is carried along by the friction with one of the plate carrier. In this case, the cooling liquid encounters the guide structure at a relative speed and is deflected by the latter in one of the directions.

In a further advantageous embodiment of the cooling liquid conveying device, at least one opening and at least one blade element are provided on at least one of the openings, wherein cooling liquid is conveyed by means of the at least one blade element in the axial direction and / or radial direction through the corresponding opening.

The openings are arranged such that they are passable for the cooling liquid used. In particular, the size of the opening is set up such that the desired amount of sales of cooling liquid with the least possible resistance can pass through the at least one opening. Preferably, a plurality of openings is provided on the surface of the disc. In particular, the disc forms a flange on the outer circumference, in which at least one opening, preferably a plurality of openings, is introduced. Furthermore, a blade element is provided at the at least one opening. For example circulating cooling liquid on such a blade element, the cooling liquid is conveyed by the relative movement between the blade element and the cooling liquid through the corresponding opening. In this case, the blades may be formed radially or tangentially, so that they convey in an existing direction of circulation of the cooling liquid these in the axial direction and / or in the radial direction through the opening. Such a coolant delivery device thus also has a passive pumping action.

In a further advantageous embodiment of the cooling liquid conveying device, the guide structure is formed at least partially from a plurality of radially extending elevations in the cooling liquid conveying device.

The radially extending elevations may be arranged in the form of webs or ribs on the disk. The elevations do not have to extend strictly radially; for example, they may also be curved or wavy from a central axis of the disk to the outer periphery of the disk. The guide structure thus preferably has a radial component. As a result, the cooling liquid is conveyed radially outward. The formation of such conductive structures is particularly easy to manufacture, for example, by prototyping or sheet metal forming a disc.

In a further advantageous embodiment of the cooling liquid conveying device, the cooling liquid conveying device is rotatable and, during a rotation, stationary or slower rotating cooling liquid can be conveyed by means of the guide structure in the axial direction and / or radial direction.

The cooling liquid delivery device preferably rotates about the axial direction. Cooling liquid having a relative velocity with respect to the cooling liquid conveying device, in particular with a rotational relative speed, is conveyed by the cooling liquid conveying device in the axial or radial direction. As a result of the rotation, the cooling liquid conveying device is used as an active pump which assists, deflects or even carries out the conveying of the cooling liquid alone. Preferably, in this case, the guide structure and / or the blade elements are aligned such that it is not directed against the circulation of the cooling liquid. Thus, the introduction of shear forces in the coolant and thus the production of heat is significantly reduced. According to a further aspect of the invention, a wet friction clutch is also described for releasably connecting a drive unit to a drive train, which has at least the following components:

a wet room which can be filled with cooling liquid;

at least one lamella basket for receiving a disk pack in the wet space for releasably frictionally connecting an input shaft to an output shaft; wherein at least one cooling liquid conveying device is provided according to the above description, which is connected either to the input shaft or to the output shaft.

The wet friction clutch is adapted to transmit a torque, the main transmission direction being directed from a drive unit to a drive train. When used in a motor vehicle but also, for example, in towing operation, a transmission of the torque from the drive train of the motor vehicle to the drive unit of the motor vehicle is possible. The friction clutch is thereby switchable during the application of a torque or a speed, so that, for example, in a subsequent manual transmission, the translation can be changed. In particular, the wet friction clutch is a starting clutch that transmits a speed and a torque to a connected stationary propulsion, for example the wheels of a motor vehicle. The wet friction clutch is smaller compared to a conventional dry friction clutch, because lower heat masses are needed to dissipate the heat generated by the friction; because the heat can be dissipated via a cooling liquid. The drive unit may be an internal combustion engine, an electric motor or the like. The drive train is often composed of a manual transmission and a shaft system for transmitting the torque of the drive unit to, for example, wheels of a motor vehicle. The wet friction clutch has a wet space, which can be filled with coolant. The cooling liquid is conveyed constantly or as required through the wet space, so that heat generated in the wet room can be dissipated.

In the wet room at least one lamellae basket is arranged, in which by means of a disk pack, an input shaft can be frictionally connected to an output shaft. The disk pack consists of a plurality of disks. By a pressing these slats are pressed against each other and detachable from each other. As a result, the slats are brought into frictional connection; that is, there is sufficient frictional force to a given torque from one blade to the other blade alone over to transfer the superimposed surfaces of the slats. A part of the slats is connected rotationally fixed to the input shaft and another part of the slats is rotationally fixed to one of the output shafts connected. The input shaft is in this case so called because it usually transmits a torque in the wet friction clutch and the output shaft is so designated because it usually transmits a torque from the wet friction clutch to connected components. However, this transmission direction can also be reversed, for example, in towing a drive unit.

During pressing and loosening a friction movement between lamellae generates heat. Due to the cooling liquid in the wet room, this heat is dissipated. To support the discharge of the heated cooling liquid, a coolant delivery device according to the above description is provided here. Advantageously, this coolant delivery device is connected either to the input shaft or to the output shaft. In order to actively operate the cooling liquid conveying device, it may be particularly expedient to arrange the cooling liquid conveying device on the input shaft because it rotates permanently starting from the drive unit. However, it is also possible to provide the cooling liquid delivery device on the output shaft in order to passively use the cooling liquid delivery device, that is to say by slower movement of the cooling liquid delivery device than the circulation of the cooling liquid or, secondly, the cooling liquid delivery device only to be activated and after to deactivate the release. In a pressed state, there is virtually no rotational relative movement, because the cooling liquid is rotated by the adjacent rotating parts. This means that the capacity of the friction clutch is precisely adapted to the conditions and then the promotion is supported when most of the heat has to be dissipated.

In a further advantageous embodiment of the wet friction clutch, the at least one coolant delivery device is formed by at least one lamellar basket.

Conventionally, a lamella basket is often composed of a disk element and a receptacle for a disk pack. In this case, the cooling liquid delivery device according to the above description can be integrated on the disc element. However, it is also possible to provide guide structures or blades and openings on the receptacle for the lamellae, which at least support a conveyance of the cooling liquid in the desired direction. Through this integral training, the production cost of Slat basket increased only slightly and the weight of the slat basket increased only slightly or possibly even reduced by the introduction of openings.

In a further advantageous embodiment of the wet friction clutch, the wet friction clutch further comprises a centrifugal oil hood and at least one Kühlflüssigkeitsförderein- direction is formed by the centrifugal oil hood.

To protect other components of the wet friction clutch or to clearly define the wet space, a centrifugal oil hood can be provided which prevents radially accelerated cooling fluid, at least for the most part, from reaching the centrifugal force beyond the centrifugal oil hood. Such a Fliehölhaube is usually disc-shaped and has a flange on the outer circumference. The Fliehölhaube can be attached to fixed or rotating components. The centrifugal oil hood can be used in particular for deflecting the inflowing cooling liquid in the axial direction and / or in the radial direction. As a result of the integral design of the cooling liquid delivery device through the centrifugal oil hood, as in relation to the lamellar basket according to the above embodiment, the advantages of only a slight increase in the cost of consolidation and a possible weight reduction arise.

In a further advantageous embodiment of the wet friction clutch, coolant is conveyed by means of the cooling fluid conveying device via a disk pack arranged radially or externally to the coolant fluid conveying device.

The main part of the heat is created in the disk pack. Due to the high shear forces, which are introduced here on the cooling liquid due to the relative movement between the friction surfaces of the slats, the cooling liquid is often transported around the disk pack around, so that the already warmed up coolant remains in the disk pack and the still cold cooling liquid passes unused to the disk pack , By a targeted guide structure, or opening and blade element, the promotion of the cooling liquid can be forced into the disk set. For this purpose, not the total pressure in the wet room must be raised, but only a local pressure increase, or even pressure reduction, be generated in the region of the disk pack. By means of this measure, the heat output can be better dissipated. In particular, a smaller amount of cooling liquid can be used, because a forward flow of the cooling liquid can be prevented. In addition, the cooling fluid can be supplied at a lower pressure by a pump arranged outside the friction clutch, so less Heat is produced when conveying the cooling liquid and thus an improved heat dissipation can take place.

In a further advantageous embodiment of the wet friction clutch, the wet friction clutch is a double clutch.

A dual clutch is usually used with a double shift transmission, wherein an input shaft with two transmission shafts via two corresponding output shafts is connectable. Accordingly, such a double clutch on two disk packs, which can be arranged differently from each other. For example, the disk packs can be arranged axially one behind the other. In this case, a central coolant delivery device for both disc packs is particularly useful. Such a coolant delivery device can be formed, for example, via the central web, which is rotationally fixed, for example, to the input shaft and forms a pressure plate for the two disk packs. Also, double clutches are known in which the disk packs are arranged radially to each other. In this case, by means of an intermediate element which separates the two disk packs from one another, a cooling liquid conveying device can be formed. In particular, in the case of a double clutch, at least one coolant delivery device is connected to one of the output shafts, so that a coolant delivery device is activated accordingly only when the corresponding output shaft is in the switched state with the input shaft always rotating and promotes coolant for this disc assembly. The other disk pack is, for example, only passively cooled.

According to a further aspect of the invention, a motor vehicle is proposed, which has a drive unit with an output shaft, a drive train and a wet friction clutch according to the above description for releasably connecting the output shaft to the drive train, wherein the drive unit in the motor vehicle in front of a driver's cab and across a longitudinal axis of the motor vehicle is arranged.

Most motor vehicles today have a front-wheel drive and therefore preferably arrange the drive unit, for example an internal combustion engine or an electric motor, in front of the driver's cab and transversely to the main drive direction. The space is particularly low especially with such an arrangement and it is therefore particularly advantageous to use a small size coupling. The installation space situation for passenger cars of the small car class according to European classification is exacerbated. The units used in a passenger car of the small car class are not significantly reduced compared to passenger cars larger car classes. Nevertheless, the available space for small cars is much smaller. The friction clutch described above has a small size and it can be used a less powerful pump, which in turn has a smaller space requirement.

Passenger cars are classified according to vehicle class according to, for example, size, price, weight, power, but this definition is subject to constant change according to the needs of the market. In the US market, vehicles of the class small cars and microcars are classified according to European classification of the class of subcompact car and in the British market they correspond to the class Supermini, for example, the class City Car. Examples of the micro car class are a Volkswagen Fox or a Renault Twingo. Examples of the small car class are an Alfa Romeo Mito, Volkswagen Polo, Ford Fiesta or Renault Clio.

The features listed individually in the claims can be combined with one another in any technologically meaningful manner and can be supplemented by explanatory facts from the description and details from the figures, wherein further embodiments of the invention are shown.

The invention and the technical environment will be explained in more detail with reference to FIGS. The figures show particularly preferred embodiments, to which the invention is not limited. In particular, it should be noted that the figures and in particular the illustrated proportions are only schematic. Show it:

1 shows schematically a wet friction clutch with a cooling liquid conveying device;

FIG. 2: a coolant delivery device for conveying in the radial direction; FIG.

FIG. 3 shows a lamella basket with integrated coolant delivery device; FIG.

FIG. 4 shows a detail of a lamella basket with coolant delivery device; FIG. 5 shows a guide structure for conveying in the axial direction; and FIG. 6 shows a motor vehicle with a wet friction clutch.

In Fig. 1, a schematic of a wet friction clutch 2 is shown with a wet room 14, in which a lamellae basket 15 is arranged for receiving a disk pack 16 about a central axis 24. Purely schematically, the input shaft 17 and the output shaft 18 are each indicated by an arrow. The cooling liquid conveying device 1 is in this case formed integrally by the centrifugal oil hood 19 and has a guide structure 4, which ensures that the cooling liquid 7 is conducted in accordance with the illustrated arrow through the lamella basket 15 or the disk pack 16. The guide structure 4 is in this case arranged on a disc 3 of the cooling liquid conveying device 1. In addition to the central axis 24, the orientation of the axial direction 8 and the radial direction 9 is indicated. In this example, the cooling liquid 7 is conveyed mainly in the radial direction 9 to the fin basket 15 out.

In Fig. 2, a cooling liquid conveying device 1 is shown in plan view, which is constructed from a rotationally symmetrical disc 3 and elevations 1 1, which form a guide structure 4 to promote cooling liquid 7 in the radial direction 9 away from the central axis 24.

In Fig. 3, a fin basket 15 is shown, which integrally forms the cooling liquid conveying device 1, which can rotate about the central axis 24. In this case, the lamella basket 15 comprises a disk 3 on which first blade elements 5, each having associated openings 10, are formed in this example.

FIG. 4 shows a section basket 15 in section, which forms the cooling liquid conveying device 1. In this case, two disks 3 are provided which have a first blade element 5 and a second blade element 6 at the opening 10, whereby the cooling liquid 7 is actively or passively conveyed in the axial direction 8 during a relative rotation between the cooling liquid conveying device 1 and the lamella basket 15.

FIG. 5 shows a blade element 6 which conveys circulating coolant 7 through the opening 10 in the radial direction 9.

In Fig. 6, a motor vehicle 20 is shown schematically, which has a drive unit 12, the output shaft 21 via a wet friction clutch 2 with a drive train thirteenth is connected, the latter being shown only schematically. The drive unit 12, which is shown here as an internal combustion engine, has an engine axle 25, which is arranged transversely to the longitudinal axis 23 of the motor vehicle 20. In addition, the drive unit 12 is arranged in the motor vehicle 20 in front of the driver's cab 22.

With the coolant liquid conveying device or wet friction clutch with cooling liquid conveying device proposed here, it is possible to increase the cooling efficiency of the cooling liquid in the wet space of the wet friction clutch or to reduce the coolant liquid flow rate.

Coolant conveying device

wet friction clutch

disc

lead compound

first blade element

second blade element

coolant

axial direction

radial direction

opening

survey

drive unit

powertrain

wet room

lamella cage

disk pack

input shaft

output shaft

centrifugal oil cover

motor vehicle

output shaft

cab

longitudinal axis

central axis ōotorachse

Claims

claims

1 . Cooling liquid conveying device (1) for a wet friction clutch (2), comprising at least one disc (3) with at least one guide structure (4,5,6) for conveying cooling fluid (7) in the axial direction (8) and / or radial direction (9 ).

2. The cooling liquid conveying device (1) according to claim 1, wherein at least one opening (10) and at least one blade element (5, 6) are provided on at least one of the openings (10), cooling liquid (7) being conveyed by means of the at least one blade element (5, 6) in the axial direction (8) and / or radial direction (9) through the corresponding opening (10) is conveyed.

3. cooling liquid conveying device (1) according to claim 1 or 2, wherein the guide structure (4) at least partially from a plurality of radially extending elevations (1 1) in the cooling liquid conveying device (1) is formed.

4. cooling liquid conveying device (1) according to one of the preceding claims, wherein the cooling liquid conveying device (1) is rotatable and during a rotating standing or slower rotating cooling liquid (7) by means of the guide structure (4,5,6) in the axial direction (8) and / or radial direction (9) is conveyed.

5. wet friction clutch (2) for releasably connecting a drive unit (12) to a drive train (13), comprising at least the following components:

a wet room (14) which can be filled with cooling liquid (7); at least one lamellae basket (15) for receiving a disk pack (16) in the wet space (14) for releasably frictionally connecting an input shaft (17) to an output shaft (18);

wherein at least one cooling liquid conveying device (1) according to one of the preceding claims is provided, which is connected either to the input shaft (17) or to the output shaft (18).

6. Wet friction clutch (2) according to claim 5, wherein the at least one Kühlflüssigkeits- conveying device (1) by at least one lamellae basket (15) is formed.

7. wet friction clutch (2) according to claim 5 or 6, wherein the wet friction clutch (2) further comprises a Fliehölhaube (19) and at least one Kühlflüssigkeitsför- dereinrichtung (1) by the Fliehölhaube (19) is formed.

8. Wet friction clutch (2) according to any one of claims 5 to 7, wherein by means of the cooling liquid conveying device (1) cooling liquid (7) via a radially to the Kühlflüssig- keitsfördereinrichtung (1) outside or inside arranged disc pack (16) is conveyed.

9. wet friction clutch (2) according to one of claims 3 to 6, wherein the wet friction clutch (2) is a double clutch.

10. motor vehicle (20) comprising a drive unit (12) with an output shaft (21), a drive train (13) and a wet friction clutch (2) according to one of claims 5 to 9 for releasably connecting the output shaft (21) with the drive train ( 13), wherein the drive unit (12) in the motor vehicle (20) in front of a driver's cab (22) and transverse to a longitudinal axis (23) of the motor vehicle (20) is arranged.