WO2008046544A1 - Hydraulic machine tool - Google Patents

Abstract

Disclosed is a hydraulic machine tool comprising a plurality of working chambers, of which the volumes change cyclically and which are connected via at least one connecting duct. An electronically triggered check valve that can be triggered by means of an electronic control unit is located inside the connecting duct. According to the invention, each check valve can be individually triggered by means of the electronic control unit in accordance with the changing volume of each working chamber such that the swallowed or conveyed volume flow can be modified between an idle mode and a fully operational mode.

Description

 description

Hydraulic working machine

The invention relates to a hydraulic working machine according to the

Preamble of claim 1.

Such, designed as a radial piston hydraulic hydraulic machine is known for example from DE 40 41 800 C2. This conventional solution has cylinder-guided pistons which are diametrically opposed in pairs and driven by an eccentric shaft. The piston / cylinder arrangements each delimit a working space with a cyclically changing volume, which is connected in each case to a low-pressure connection and a high-pressure connection. The work spaces are connected via a connecting channel in which an electronically controlled, operable from an open position against the force of a return spring in a blocking position blocking valve is provided which can be controlled via an electronic control unit. If the switching valve in its open position, there is no pressure medium delivery to the high-pressure connection, since only pressure medium is displaced via the connecting line between the working spaces of the piston / cylinder arrangements. When the shut-off valve is closed, pressure medium is conveyed to the high-pressure port. A disadvantage of such hydraulic machines is that the switching valves associated with the piston / cylinder arrangements are actuated together, so that only a stepwise change of the delivery volume flow is possible. Furthermore, a high pulsation of the delivery or suction volume flow occurs.

In contrast, the present invention seeks to provide a hydraulic see machine, in which an improved control of the delivery or suction volume flow is made possible with minimal manufacturing effort. This object is achieved by a hydraulic working machine having the features of patent claim 1.

The working machine according to the invention has a multiplicity of work spaces with cyclically changing volumes, which are each connected to a low-pressure connection and a high-pressure connection, between which connection channels (36) are provided, in each of which an electronically controlled shut-off valve is arranged an electronic control unit is controllable. According to the invention, each shut-off valve can be controlled individually via the electronic control unit as a function of the changing volume of each working space, so that a change in the sip or delivery volume flow between an idle mode in which the usable volume of a working space is substantially displaced into the other working space and a full mode in which essentially all the usable volume of the workrooms is used. That is, the idle mode or a partial mode is realized by the volume of a working space is timely controlled completely or partially ejected in the other working space of the pair of working over a controlled by the electronic control unit check valve to change the time-averaged effective flow through the machine and to achieve a low pulsation of the delivery or suction volume flow. This solution has the advantage that a substantially continuous change of the delivery or suction volume is achieved with minimal pulsation with minimal manufacturing effort, since the check valves over the prior art according to DE 40 41 800 C2 are individually controlled.

The hydraulic working machine can be designed, for example, as a radial piston machine, in particular as a radial piston pump, wherein the working spaces are preferably bounded by pistons which can be moved back and forth in cylinders.

According to a particularly preferred embodiment of the invention, only a portion of the usable volume of the work spaces is moved in a partial mode. Advantageously, the check valves are controlled in the manner of a rotating field and optimized for pulsation.

The check valves connect, for example, in each case directly successive working spaces with each other.

In another advantageous embodiment, the number of work spaces is even and a check valve connects two 180 ° offset from each other work rooms together.

The check valve opens in partial mode preferably a defined time before the top dead center of the piston, wherein a portion of the usable volume is moved to the other working space (phase control section). As a result, for example, during pump operation, the low-pressure piston chambers are prefilled at idling and partial delivery, so that an improvement in the efficiency, the pumping speed and the cavitation resistance is achieved. Since the switching of the idling or the partial delivery is possible at any time of the displacement, in addition to the phase portion control, a phase control and / or a phase cut control can be realized.

In a phase control, the check valve is opened in the partial mode a defined time after the bottom dead center of the piston, so that a portion of the usable volume is moved into the other working space.

According to a drive variant with phase cutout control, the check valve in the partial mode opens a defined time between the bottom and the top dead center of the piston, so that a portion of the usable volume is moved into the other working space. By a combination of the Phasenanschnitts-, Phasenabschnitts- and / or phase cut control, the possibilities for influencing the delivery or suction volume and the Pulsationsminimierung can be further improved. - A -

The electronic control unit preferably controls the shut-off valve as a function of a characteristic curve, a program or a setpoint specification for pressure and / or volume flow. The switching mode is preferably selected by an electronic system and a controller algorithm (computer program) in such a way that the lowest possible volume-flow volume flow of a pump or sum-sip volume flow of a hydraulic motor is achieved.

In a preferred embodiment of the invention, the hydraulic work machine has an even number of work spaces, i. at least two working spaces, on, which are each connected via a connecting channel.

It has proven to be particularly advantageous if the check valve is designed as a 2/2-way valve. Preferably, the check valve is magnetically actuated.

The outlet and / or supply lines of the working spaces are combined in one embodiment of the invention into a low-pressure or high-pressure main line. Thereby, the pulsation of the sum-flow volume flow of a pump or the sum-sip volume flow of a hydraulic motor can be further reduced.

Other advantageous developments of the invention are the subject of further subclaims.

The invention will be explained in more detail with reference to three preferred embodiments. Show it:

Figure 1 is a schematic representation of a designed as a radial piston pump according to the invention hydraulic working machine according to a first embodiment. Fig. 2 is a schematic representation of a radial piston pump according to a second embodiment; and

Fig. 3 is a schematic representation of a radial piston pump according to a third embodiment.

1 shows a designed as a radial piston pump 1 inventive hydraulic working machine according to a first embodiment with an even number of diametrically opposed cylinders 2, 4, in each of which a piston 6, 8 is slidably guided, with the cylinders 2, 4 each one Working space 10, 12 limited with cyclically changing volume, with only two cylinder / piston arrangements are shown in the figure for reasons of clarity. Each working space 10, 12 is connected via a high-pressure line 14, 16 to a common high-pressure connection P (pressure connection) and via a low-pressure line 18, 20 to a common low-pressure connection S (suction connection). In the high-pressure lines 14, 16 in each case one in the direction of the working spaces 10, 12 blocking check valve 22, 24 is arranged, which acts as a pressure valve and prevents a pressure medium backflow from the high pressure port P in the working spaces 10, 12. In the

Low pressure lines 18, 20 is in each case one in the direction of the working spaces 10, 12 opening, working as a suction valve check valve 26, 28 is arranged. The pistons 6, 8 are driven via a drive shaft 29, which is provided in the region of the pistons 6, 8 with an eccentric 30, so that they are biased by piston rods 32, 34, against which the pistons 6, 8 with a piston foot , in the rotational movement of the eccentric shaft 30 perform an opposite input and extension movement. The work spaces 10, 12 are each connected via a connecting line 36, in which an electronically controlled, operable from an open position shown in a blocking position blocking valve 38 is provided which via an electronic control unit, not shown, depending on the changing volume of each of the working spaces 10, 12 is controlled. Each of a cylinder / piston pair associated shut-off valves 38 can be controlled individually via the electronic control unit, so that a change in the delivery volume flow between an idle Mode in which the usable volume of a working space 10, 12 is substantially moved to the other working space 12, 10 and a full mode in which substantially all the usable volume of the working spaces 10, 12 is used, is reached. It has proven to be particularly advantageous if the check valve 38 is designed as a magnetically actuated 2/2 way valve.

For a better understanding of the working machine 1 according to the invention, its function will be briefly described below.

According to FIG. 1, the upper piston 6 is at top dead center, so that the working space 10 has its smallest and the working space 12 has its maximum volume. The piston 6 moves during the rotational movement of the drive shaft 30 in the direction of the eccentric. The working space 10 increases, wherein the non-return valve 26 operating as a suction valve opens by the resulting negative pressure. Pressure fluid flows from the low pressure port S via the low pressure line 18 and the open suction valve 26 in the increasing working space 10. The piston 8 is at bottom dead center, the working chamber 12 is completely filled with pressure medium. The suction valve 28 is closed. With the rotational movement of the drive shaft 30, the piston 8 is moved via the eccentric 30 and the piston rod 34 in the direction of top dead center. With open check valve 38 (see figure), the usable volume of the working space 12 is moved via the connecting line 36 into the working space 10 of the piston 6, so that in the open position of the check valve 38 no pressure medium to the

High pressure port P is promoted (idle mode). The pressure valves 22, 24 are in this case closed, for example spring or pressure loaded. If now the check valve 38 is closed, so that the pressure medium connection between the work spaces 10, 12 interrupted by the connecting line 36, so is substantially the whole usable volume of

Workspace 12 shifted and the full flow is available (full mode). In this case, the pressure medium in the working chamber 12 is completely conveyed to the high-pressure connection P via the non-return valve 24 operating as a pressure valve and the high-pressure line 16. In a partial mode, only a portion of the usable volume of the work spaces 10, 12 is moved. The check valve 38 opens in partial mode, for example, a defined time before the top dead center of the piston 8, wherein a portion of the usable volume via the connecting line 36 is moved into the working space 10 of the piston 6 (phase control). As a result, the working space 10 is pre-filled, so that an improvement in the efficiency, the pumping speed and the cavitation resistance is achieved.

Since the switching of the idling or the partial conveying is possible at every time of the displacement, in addition to the phase-section control, phase-angle control and phase-cut control can be realized. In a phase control, the check valve 38 remains open a defined time after the bottom dead center of the piston 8, so that a portion of the usable volume flow is displaced via the connecting line 36 into the working chamber 10 of the piston 6. Subsequently, the check valve 38 is closed and the remaining volume via the high pressure line 16 and the opening pressure valve 24 to the high pressure port P promoted (partial flow promotion). According to a control variant with phase cutout control, the blocking valve 38 opens a defined time in the partial mode between the lower and upper dead center of the piston 8, so that part of the usable volume flow is displaced into the other working space 10. Subsequently, the check valve 38 is also closed again and the remaining volume via the high-pressure line 16 and the opening pressure valve 24 is conveyed to the high pressure port P. The electronic control unit controls the shut-off valve 38 in this case in response to a characteristic curve, a program or a setpoint specification for pressure and or flow. By combining the phase control, phase section and / or phase cutout control, the possibilities for influencing the delivery volume and the volume flow pulsation can be further improved. A second embodiment of a hydraulic working machine is shown in FIG. This radial piston machine 1 has, in contrast to the first embodiment in Figure 1, an odd number of cylinders 40, 42, 44, 46, 48, which are arranged in a star shape around the drive shaft 29 around. Each working space 50 of a cylinder 40-48 is connected via a connecting line 52, in which a check valve 54, 56, 58, 60, 62 is provided, with the working space 50 of its respective adjacent cylinder 40-48. For example, between the cylinder 42 and its cylinder 44, viewed in the direction of rotation (see Fig. 2) of the drive shaft, the blocking valve 56 is arranged. Viewed against the direction of rotation, cylinder 40 is the adjacent cylinder of cylinder 42, between which the check valve 54 is interposed. The check valves 54, 56 in the open state in each case a connection of the working chambers of the cylinder 40, 42 and the cylinder 42, 44 ago. The check valves 54-62 can each be regulated or controlled individually, independently of each other and with a variable time. During operation of the radial piston pump 1, it is therefore possible to control it in a rotational field-like manner, ie continuously in rotation about the axis of rotation of the drive shaft 29, and in a manner optimized for pulsation. Usable volume is in this case either from a cylinder 40 in the direction of rotation (see Fig. 2) leading to the next cylinder 42 leading, lagging towards the next cylinder 48 seen against the direction of rotation or simultaneously moved to these two adjacent cylinders 42, 48. In a leading control, for example, check valve 56 is opened, closed again after a certain time and for this purpose shut-off valve 58 is opened and so on. The control of the check valves 54-62 is variable, so that a wide variety of variations are possible and not adjacent check valves 54-62 can be opened and closed simultaneously or at different times. A complete idle circuit or idle mode as in the first embodiment in Figure 1 is not possible because the working spaces 50 of the cylinder 40-48 have different high volume change during rotation and the difference in volume change of all working spaces 50 does not give zero, but something is larger. However, it is conceivable that the difference in the volume change is compensated by the compressibility of the pressure medium. In Figure 3, a third embodiment is disclosed with a radial piston machine 1 which three cylinders 64, 66, 68, between which the check valves 70, 72, 74 are arranged. This radial piston machine 1 basically has the same construction as the radial piston machine 1 from FIG. 2, so that reference is made to the embodiment of FIG. 2 for a detailed description.

The working machine 1 according to the invention is not limited to the described radial piston pumps, but the working machine 1 may be formed as a radial piston motor or axial piston machine. Furthermore, the invention is not limited to reciprocating engines, for example, the working machine may be designed as a vane pump or vane motor. Also in the pneumatic field, use of this working machine 1 is possible, compressed air being used instead of pressurized fluid. Another possible use of this machine 1 would be conceivable as an air compressor.

Disclosed is a hydraulic working machine 1 with a plurality of working spaces 10, 12 with cyclically changing volume, which are connected via at least one connecting channel 36, in which an electronically controlled shut-off valve 38 is provided, which is controlled via an electronic control unit. According to the invention, each shut-off valve 38 can be individually controlled via the electronic control unit as a function of the changing volume of each working space 10, 12, so that a change in the sip or delivery volume flow is achieved between an idle mode and a full mode.

Claims

claims 1. Fluidic working machine, in particular hydraulic pump or hydraulic motor, with a plurality of working spaces (10, 12) with cyclically changing volume, which are each connected to a low pressure port (S) and a high pressure port (P), between which connecting channels (36) are provided are, in each of which an electronically controlled shut-off valve (38) is arranged, which is controlled by an electronic control unit, characterized in that each check valve (38) via the electronic control unit in response to the changing volume of each working space (10, 12) individually is controllable, so that a change in the swallowing or delivery volume flow between an idle mode, in which the usable volume of a working space (10, 12) substantially in the other working space (12, 10) is moved and a full mode, in the substantially the entire usable volume of the work spaces (10, 12) is used is reached. 2. Hydraulic machine according to claim 1, wherein in a partial mode, only a portion of the usable volume of the working spaces (10, 12) is moved. 3. Hydraulic working machine according to claim 1 or 2, wherein this is designed as a radial piston machine, in particular as a radial piston pump (1). 4. Hydraulic working machine according to one of the preceding claims, wherein the check valves (54-62) are successively controlled by a rotary field. 5. Hydraulic working machine according to one of the preceding claims, wherein the check valves (54-62) each directly successive working spaces (50) connect to each other. 6. Hydraulic working machine according to one of the preceding claims, wherein the number of working spaces (10, 12) is even and a check valve (38) connects two 180 ° staggered work spaces (10, 12) with each other. 7. Hydraulic working machine according to one of the preceding claims, wherein the working spaces (10, 12) of in cylinders (2, 4) reciprocating piston (6, 8) are limited. 8. Hydraulic working machine according to claim 7, wherein the Block valve (38) in the partial mode a defined time before top dead center of the piston (6, 8) is open and / or the check valve (38) a defined time after the bottom dead center of the piston (6, 8) is open and / or Blocking valve (38) a defined time between the bottom dead center of the piston (6, 8) and the top dead center of the piston (6, 8) is opened and a portion of the usable volume in the other working space (10, 12) is moved. 9. Hydraulic working machine according to one of the preceding claims, wherein a check valve (38) in response to a characteristic curve, a program or a setpoint input for pressure and or flow rate is controlled via the electronic control unit. 10. Hydraulic working machine according to one of the preceding claims, wherein a check valve is designed as a 2/2-way valve. 11. Hydraulic working machine according to one of the preceding claims, wherein a check valve is magnetically actuated. 12. Hydraulic working machine according to one of the preceding Claims, wherein the working spaces (10, 12) associated with outlet and / or supply lines (14, 16, 18, 20) to a common Niederdruckbzw. High pressure main are summarized.