Actuation device comprising a hydraulic brake, hydraulic actuation system, and powertrain
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- SCHAEFFLER TECHNOLOGIES AG & CO KG
- Filing Date
- 2024-08-01
- Publication Date
- 2026-07-08
Smart Images
Figure DE2024100679_06032025_PF_FP_ABST
Abstract
Description
[0001] Actuating device with hydraulic brake, hydraulic actuating system and drive train
[0002] The invention relates to an actuating device for actuating a clutch device having the features of the preamble of claim 1. Furthermore, the invention relates to a hydraulic actuating system having the actuating device and to a drive train having the actuating device and / or the actuating system.
[0003] Concentric slave cylinders (CSC) are typically used in both hybrid and purely electric vehicle drive systems. These serve, for example, to separate the electric motor from the combustion engine or to change gears. Such slave cylinders essentially consist of an annular housing and an annular piston that can be axially displaced within the housing. The annular piston is operatively connected to a clutch in such a way that the clutch is actuated, in particular, engaged.
[0004] The document DE 10 2020 109 989 A1 discloses a clutch device for a motor vehicle, with a shaft, wherein the shaft extends axially, with a clutch section, wherein the clutch section is arranged coaxially to the shaft and rotates with the shaft, wherein axial and radial forces act on the shaft and / or on the clutch section during rotation of the shaft, wherein at least the radial forces can cause a radial offset of the clutch section and / or a misalignment of the clutch section and / or the shaft, and with a release bearing, wherein the release bearing is axially movable for transmitting an actuating force to the clutch section, wherein the release bearing is guided through the shaft and / or on the shaft in the radial direction to compensate for the axial offset and / or the misalignment.It is an object of the present invention to propose an actuating device which is characterized by a high operational reliability when actuating the coupling device.
[0005] This object is achieved by an actuating device having the features of claim 1, a hydraulic actuating system having the features of claim 9, and a drive train having the features of claim 10. Preferred or advantageous embodiments of the invention emerge from the subclaims, the following description, and the attached figures.
[0006] The subject matter of the invention is an actuating device designed and / or suitable for actuating a clutch device. In particular, the actuating device serves to transmit an actuating force to the clutch device in order to open or close the clutch device. The clutch device is preferably designed as a friction clutch, preferably a friction-disk clutch. Particularly preferably, the actuating device is hydraulically actuated.
[0007] For this purpose, the actuating device has a concentric slave cylinder, also known as a “concentric slave cylinder (CSC),” which essentially comprises an annular piston and an annular housing. In particular, the concentric slave cylinder is designed as a central release cylinder. The annular piston and the annular housing are preferably arranged coaxially and / or concentrically with respect to a main axis. The annular housing preferably has a central through-opening, in particular a bore, through which at least one shaft can be passed when the actuating cylinder is installed. The main axis is preferably defined by a rotational axis of the shaft. The annular piston is preferably rotationally symmetrical with respect to the main axis.
[0008] The annular housing has an annular space surrounding the main axis, wherein the annular piston is accommodated in the annular space of the annular housing so as to be movable axially with respect to the main axis. The annular space is delimited axially with respect to the main axis by the annular piston, so that a pressure chamber that can be filled with a hydraulic fluid is formed between the annular piston and the annular housing. In particular, the annular space is open on one side in the axial direction delimited by the annular piston and closed in an axially opposite direction. When the slave cylinder is actuated, the pressure on the hydraulic fluid is increased, wherein the actuating force is generated due to the rising pressure in the pressure chamber and is transmitted to the annular piston, so that the latter is disengaged axially. In particular, the hydraulic fluid is a hydraulic fluid, more specifically a hydraulic oil.
[0009] The actuating device further comprises a housing section, wherein the annular housing is accommodated in the housing section, and an intermediate pressure chamber is formed radially between the annular housing and the housing section, surrounding the rotational axis. The housing section can be formed by a clutch housing, a transmission housing, or a motor housing. Preferably, the intermediate pressure chamber is bounded in the radial direction by an inner circumference of the housing section and an outer circumference of the annular housing.
[0010] The intermediate pressure chamber is fluidically connected, on the one hand, to the pressure chamber via at least or exactly one fluid opening formed in the annular housing and, on the other hand, to a pressure connection via a pressure connection opening formed in the housing section. In principle, the annular housing can have exactly one fluid opening, which can be arranged at any position viewed in the circumferential direction. Alternatively, however, the annular housing can also have a plurality of fluid openings that are distributed in the circumferential direction and / or evenly spaced from one another. The at least one fluid opening can be arranged on a radial outer side of the annular housing and / or open radially into the pressure chamber or the intermediate pressure chamber. For this purpose, the fluid opening can be formed by a bore or the like made radially in the annular housing. In particular, the pressure connection serves to connect a pressure line.The pressure connection can be arranged on a radial outer side of the housing section. For example, the pressure connection can be fluidly connected to the pressure connection opening via at least one or precisely one bore or the like introduced into the housing section. In particular, a fluid flow path runs via the pressure connection opening, the intermediate pressure chamber, and the at least one fluid opening into the pressure chamber. In other words, the pressure chamber can be supplied with fluid from the pressure connection via the pressure connection opening, the intermediate pressure chamber, and the at least one fluid opening. Particularly preferably, the pressure line is directly connected to the pressure connection.
[0011] Within the context of the connection, it is proposed that a hydraulic brake be formed between the pressure connection and the intermediate pressure chamber, which brake decelerates a pulsating flow, in particular from the intermediate pressure chamber via the pressure connection opening to the pressure connection, of a hydraulic fluid displaced by the annular piston during movement of the annular piston by increasing flow resistance. In particular, the hydraulic brake serves to reduce or dampen pressure pulsations during actuation of the slave cylinder by increasing flow resistance in the area of the pressure connection opening. The hydraulic brake can be implemented by a separate component and / or a geometric modification of the annular housing and / or the housing section.
[0012] The invention is based on the finding that during actuation of the slave cylinder in combination with a crooked clutch device, high vibrations / dynamics occur, which are reflected as a strong wobbling movement in the annular piston. This creates strong fluid dynamics that lead to pressure pulsations. These pressure pulsations negatively influence the entire system and can even lead to failure or to the actuation device no longer being able to be pressure-controlled. The invention is based on the idea that pulsating flows or pressure pulsations can be influenced via flow resistance. The higher the flow resistance, the greater the damping effect. By arranging or forming a hydraulic brake between the intermediate pressure chamber and the pressure connection, the flow resistance can be easily increased as close to the slave cylinder as possible.An actuating device is thus proposed which is characterized by high operational reliability and robust operation, particularly in combination with an oblique coupling device.
[0013] In a specific embodiment, the hydraulic brake is formed by a brake gap formed radially between the annular housing and the pressure connection opening. In particular, the brake gap is defined by a radial distance with respect to the main axis between the pressure connection opening and the annular housing. Preferably, the radial distance between the housing section and the annular housing at the location of the pressure connection opening is many times smaller, for example by at least 50%, than a radial distance between the housing section and the annular housing at the location of the fluid opening. The flow resistance is increased by the fact that, when the annular piston moves, part of the displaced hydraulic fluid is forced via the brake gap into the pressure connection opening.Put simply, the flow resistance in the brake gap is large compared to the flow resistance in the rest of the system, particularly the intermediate pressure chamber and / or the pressure port. This proposes a particularly cost-effective way to increase the flow resistance.
[0014] In a specific implementation, the intermediate pressure chamber in the region of the pressure connection opening is designed as an annular gap running around the main axis, which has a reduced gap width compared to the rest of the intermediate pressure chamber to form the braking gap. In particular, the pressure connection opening opens directly into the annular gap to increase the flow resistance. The annular gap preferably has a gap width of less than 10 mm, preferably less than 5 mm, in particular less than 1 mm. Alternatively or optionally additionally, the intermediate pressure chamber outside the annular gap has a radial distance of more than 10 mm, preferably more than 15 mm, in particular more than 20 mm. In principle, the annular gap can have a constant reduced gap width in the circumferential direction. Alternatively, however, it can also be provided that the annular gap has a reduced gap width only at the location of the pressure connection opening.A hydraulic brake is thus proposed which can be implemented particularly cost-effectively by geometrically adapting the intermediate pressure chamber.
[0015] In an alternative or optionally additional embodiment, the hydraulic brake is formed by a cylinder bushing inserted into the pressure connection opening. In particular, the cylinder bushing is inserted or plugged into the pressure connection opening radially or obliquely with respect to the main axis, in particular at an angle of more than 45°, preferably more than 65°, especially more than 85°. In particular, the cylinder bushing serves to extend the through-opening in the direction of an outer circumferential surface of the annular housing. For example, the cylinder bushing can be fixed in the pressure connection opening in a force-locking manner, e.g. by a press fit. The flow resistance is increased by the fact that, when the annular piston moves, part of the displaced hydraulic fluid is pressed via the cylinder bushing into the pressure connection opening.Put simply, the flow resistance in and / or immediately upstream of the cylinder liner is large compared to the flow resistance in the rest of the system through which the fluid flows, particularly the intermediate pressure chamber and / or the pressure port. Thus, a hydraulic brake is proposed that can be implemented particularly easily by using a separate component. Furthermore, the cylinder liner has the advantage that the hydraulic brake can be easily retrofitted into existing braking systems.
[0016] In one specific embodiment, the cylinder liner protrudes at least partially into the intermediate pressure chamber, so that the cylinder liner forms an interfering contour and / or a braking gap in the intermediate pressure chamber to increase the flow resistance. In particular, the pulsating flow and / or a flow path from the intermediate pressure chamber in the direction of the pressure connection is braked or diverted by the interfering contour. Alternatively or optionally additionally, the pulsating flow is braked by the braking gap, which is formed radially between the end of the cylinder liner protruding into the intermediate pressure chamber and the annular housing. Preferably, the cylinder liner protrudes so far into the intermediate pressure chamber that a radial distance between the cylinder liner and the annular housing is smaller than a minimum distance between the housing section and the annular housing.Particularly preferably, the cylinder liner extends into the intermediate pressure chamber by more than 40%, preferably more than 60%, and especially more than 80% of the radial distance between the pressure connection opening and the annular housing. This allows the pulsating flows from the intermediate pressure chamber into the pressure connection opening to be easily slowed.
[0017] In an alternative or optionally additional embodiment, the cylinder liner has a central through-opening which, in order to increase the flow resistance, has a reduced opening cross-section compared to the pressure connection opening. In particular, the pulsating flow from the intermediate pressure chamber in the direction of the pressure connection is braked by the reduced opening cross-section. In principle, the cylinder liner can be arranged entirely within the housing section. However, the cylinder liner preferably projects at least partially into the cylinder pressure chamber in order to additionally influence the flow resistance by forming the interfering contour and / or the braking gap. For example, the opening cross-section of the through-opening can be reduced by at least 10%, preferably more than 30%, in particular more than 50% compared to the opening cross-section of the pressure connection opening.Particularly preferably, the through-hole is designed as a through-bore that extends the pressure connection opening toward the outer surface of the annular housing with the reduced opening cross-section. By dimensioning the opening cross-section, the flow resistance can thus be easily adapted to the expected pressure pulsations. In a further specific embodiment, the cylinder liner has a closed cylinder surface. In particular, a fluid flow path runs from the intermediate pressure chamber exclusively via the through-hole to the pressure connection. Thus, a cylinder liner is proposed that is characterized by simple and cost-effective production.
[0018] In an alternative embodiment, the cylinder liner has a plurality of radial through-openings. In particular, a fluid flow path is divided into a main flow path running via the through-opening and a plurality of secondary flow paths running via the through-openings. In particular, at least the part of the cylinder liner protruding into the intermediate pressure chamber has the through-openings. Alternatively, however, the through-openings can also be distributed over the entire circumference. Preferably, through-openings are spaced apart and / or evenly distributed in the axial direction and / or in the circumferential direction with respect to a longitudinal axis of the cylinder liner. Preferably, the through-openings each have a significantly smaller opening cross-section than the through-opening. The through-openings can be designed as radial bores which open into the central through-opening.By dividing the flow path, the pulsating flow can be further influenced to dampen the pressure pulsations.
[0019] Another subject of the invention relates to a hydraulic actuation system for a vehicle, comprising the actuation device as described above. In particular, the actuation system serves to hydraulically generate an actuation pressure upon actuation of the slave cylinder, so that an actuation force resulting from the actuation pressure is transmitted to the annular piston, causing it to be axially disengaged.
[0020] For this purpose, the actuation system comprises a pump which is designed and / or suitable for generating an actuation volume flow for the slave cylinder, wherein the pump is connected on a pressure side to the pressure connection of the housing section via a pressure line. In particular, the pump serves to build up and maintain the actuation pressure on the pressure side or in the pressure chamber of the slave cylinder. In particular, the pump is designed as an electrically operated pump. This means that the pump can be driven by a separate electric motor. Preferably, the fluid pump is connected to a fluid source on a suction side via a suction line.
[0021] Furthermore, the actuation system has a pressure control valve connected in parallel to the pump, which is designed and / or suitable for limiting an actuation pressure on the pressure side. In particular, the pressure control valve is designed to control the fluid flow on the pressure side depending on the actuation pressure on the pressure side. Preferably, the pressure control valve is closed until the actuation pressure is reached and maintained, and is opened when it is exceeded and the actuation pressure is reduced. In particular, the pump and the pressure control valve are part of a Smart Hydraulic Actuator (SHA). For this purpose, the pressure control valve can be connected to a branching point of the pressure line on the slave cylinder side.
[0022] A further subject of the invention relates to a drive train for a vehicle, with at least or exactly one drive motor, with at least or exactly one clutch device and with the actuating device and / or the hydraulic actuating system, as already described above.
[0023] The drive motor is preferably designed as an electric machine. It can be provided that the drive motor forms the only traction machine for the vehicle. Alternatively, the vehicle has further traction machines, for example a further electric machine and / or an internal combustion engine for generating the drive torque. The drive motor can be assigned to a single driven wheel of the vehicle and / or be designed as a single-wheel drive. Alternatively, the drive motor is assigned to two driven wheels, preferably a common axle, and / or is designed as an electric axle. In other embodiments, the drive motor can also be assigned to all driven wheels of the vehicle and / or be designed as an all-wheel drive.
[0024] The clutch device is designed to decouple the drive engine in certain driving situations and / or to disconnect a drive torque path, wherein the actuating device, in particular the slave cylinder, is designed and / or suitable for actuating the coupling device. In particular, the clutch device is designed as a separating clutch, also referred to as a KO clutch, which is designed to disconnect the drive torque path downstream of the drive engine. This allows the drive engine to rotate without any drive torque being transferred to the driven wheels.
[0025] Further features, advantages, and effects of the invention will become apparent from the following description of preferred embodiments of the invention. These show:
[0026] Fig. 1 is a schematic representation of a drive train as an embodiment of the invention;
[0027] Fig. 2 is a schematic representation of a hydraulic actuation system for actuating a clutch device;
[0028] Fig. 3 is a sectional view of a clutch arrangement with an actuating device and a clutch device;
[0029] Fig. 4 an alternative embodiment of the actuating device of the
[0030] Coupling arrangement in the same representation as in Fig. 3;
[0031] Fig. 5 is a schematic sectional view of a cylinder liner for the
[0032] Actuating device according to Fig. 4; Fig. 6 shows an alternative embodiment of the cylinder bushing in the same representation as in Fig. 5;
[0033] Figure 1 shows a highly schematic drive train 1 for a vehicle as an exemplary embodiment of the invention. The drive train 1 comprises a drive module 2 with a clutch assembly 3 and a drive motor 4.
[0034] The drive train 1 further comprises a further drive motor 5, which is drive-technically coupled and / or can be coupled to the drive motor 4 via the clutch assembly 3. The drive motor 4 and the further drive motor 5 can each be designed as an electric machine. Alternatively, however, the further drive motor 5 can also be designed as an internal combustion engine. For example, the drive module 2 can be designed as a so-called hybrid module.
[0035] The clutch assembly 3 is designed as a separating clutch, also called a KO clutch, which is designed to interrupt the drive torque between the two drive motors 4, 5. When the clutch assembly 3 is closed, a shaft 6, e.g., a rotor shaft, of the drive motor 4 and another shaft 7, e.g., a crankshaft, of the further drive motor 5 are rotationally fixedly coupled to one another, and when open, they are rotatable relative to one another.
[0036] The drive train 1 also has a transmission device 8, which is connected on the input side to the drive engine 4 or the additional drive engine 5 and on the output side to a differential 9, wherein a torque generated by the drive engine 4 and / or the additional drive engine 5 is transmitted or translated via the transmission device 8 to the differential 9 and thus to the driven wheels 10 of the vehicle. For example, the transmission device 8 can be designed as a dual-clutch transmission. Figure 2 shows a hydraulic actuation system 11, which is designed and / or suitable for actuating the clutch arrangement 3. For this purpose, the actuation system 11 has an actuation device 12 with a concentric slave cylinder 13, CSC for short, which is arranged or can be arranged coaxially and / or concentrically to the shaft 6 and / or the additional shaft 7.The slave cylinder 13 serves to actuate a clutch device 30, as shown in Figures 3 and 4, wherein the slave cylinder 13 is coupled in motion to an actuating member of the clutch device 30 for this purpose.
[0037] The slave cylinder 13 has an annular housing 14 and an annular piston 15 accommodated in the annular housing 14, which is axially movable relative to the annular housing 14 with respect to a main axis 100 of the shaft 6 or the further shaft 7 between an engaged and a disengaged end position 101, 102. The annular housing 14 and the annular piston 15 are arranged coaxially and concentrically with respect to the main axis 100.
[0038] In certain ferry operations where no propulsion energy is required, such as sailing operations, the slave cylinder 13 is actuated to open the coupling device 30. Shaft 6 and the further shaft 7 are thus drive-technically separated from each other, so that no energy is transferred to the wheels 10 and the vehicle continues to roll without actively consuming energy from the battery.
[0039] The annular piston 15 forms a radial seal within the annular housing 14, so that a pressure chamber 16 is axially delimited or sealed by the annular piston 15. The slave cylinder 13 is hydraulically actuated, wherein the pressure chamber 16 is filled with a hydraulic fluid, e.g., hydraulic oil, in an operating state. For this purpose, the annular housing 14 has at least one fluid opening 17 on a radial outer side, through which the pressure chamber 16 is supplied with the hydraulic fluid.
[0040] The actuating device 12 has a housing section 18 in which the annular housing 14 is at least partially accommodated. An intermediate pressure chamber 19 is formed radially between the annular housing 14 and the housing section 18, which chamber 19 surrounds the main axis 100 and is fluidly connected to a pressure connection 21 of the housing section 18 via a pressure connection opening 20 formed in the housing section 18. The fluid opening 17 fluidly connects the pressure chamber 16 to the intermediate pressure chamber 19. For example, the housing section 18 is designed as a housing of the drive motor 4, the further drive motor 5, or the transmission 8.
[0041] The hydraulic actuation system 11 has a Smart Hydraulic Actuator (SHA), which essentially comprises a pump 22, a pressure control valve 23, and a check valve 24. The pump 22 is fluidly connected on a pressure side 25 via a pressure line 27 to the pressure port 21 of the housing section 18, wherein the pump 22 generates an actuation volume flow 103, which, during operation, flows from the pump 22 via the pressure line 27 and the intermediate pressure chamber 19 into the pressure chamber 16, thereby increasing the pressure in the pressure chamber 16 and applying an actuation force to the annular piston 15. For this purpose, the pump 22 is connected on a suction side 26 via a suction line 28 to a fluid source 29. For example, the fluid source 29 can be an oil sump.
[0042] The check valve 24 is connected on the pressure side 25 in series with the pump 22 in the pressure line 27, whereby the check valve 24 permits flow toward the slave cylinder 13 and prevents flow toward the pump 22. The check valve 24 serves to maintain the actuating pressure in the slave cylinder 13 when the pump 22 is at a standstill.
[0043] The pressure control valve 23 is connected on the pressure side 25 in parallel to the pump 22, wherein the pressure control valve 23 limits the actuating pressure. For this purpose, the pressure control valve 23 can be switched at least between a blocking position and an open position depending on the actuating pressure on the pressure side 25, wherein pressure builds up in the blocking position and pressure decreases in the open position. When the slave cylinder 13 is actuated, the pump 22 pumps the hydraulic fluid into the pressure chamber 16 until a predetermined target pressure is reached, wherein the pressure control valve 23 switches to the open position, at least briefly, when the target pressure is reached, in order to maintain the actuating pressure at a constant pressure level. For this purpose, the pressure control valve 23 can be designed as a pressure-controlled directional control valve, e.g. a 2 / 2-way valve. In principle, the excess quantity of hydraulic fluid can be fed via the pressure control valve 23 directly to the fluid source 29, as shown in Fig.2. Alternatively, the excess hydraulic fluid can also be supplied elsewhere, e.g., for cooling and / or lubricating the drive motor 4 and / or the additional drive motor 5 and / or the transmission 8.
[0044] As shown in Figure 3, the clutch assembly 3 is essentially constructed from the clutch device 30 and the actuating device 12, which are arranged coaxially with respect to a main axis 100. The shaft 6 forms an output shaft, and the further shaft 7 forms an input shaft of the clutch assembly 3 or the clutch device 30. The shaft 6 and the further shaft 7 are arranged coaxially and / or concentrically with respect to the main axis 100, with the shaft 6 being designed as a hollow shaft and the shaft 7 as a solid shaft guided through the hollow shaft or as a further hollow shaft.
[0045] The annular housing 14 has an annular chamber 31 which is open on one side axially with respect to the main axis 100 and in which the annular piston 15 is received so as to be axially displaceable with respect to the main axis 100 and delimits the pressure chamber 16. To seal the pressure chamber 16, the slave cylinder 13 has an outer and an inner sealing ring 32, 33, wherein the annular piston 15 bears sealingly against the annular housing 14 in a radial direction via the outer sealing ring 32 in a radial direction with respect to the main axis 100 and via the inner sealing ring 33 in a radially opposite direction with respect to the main axis 100 within the annular chamber 31. The two sealing rings 32, 33 are each designed as an elastomer seal, in particular as grooved sealing rings, which are captively attached to the annular piston 15.For this purpose, the slave cylinder 13 has a retaining ring 34 which is designed to secure the two sealing rings 32, 33 axially with respect to the main axis 100 against loss and / or slipping on the annular piston 15.
[0046] As already described in Figure 2, the intermediate pressure chamber 19 is formed radially between the annular housing 14 and the housing section 18. The slave cylinder 13 has a first and a second sealing ring 35, 36, which seal the intermediate pressure chamber 19 in a fluid-tight manner. For this purpose, the two sealing rings 35, 36 are fixed to the radial outer side of the annular housing 14, wherein the first seal 35 bears circumferentially in the radial direction with respect to the main axis 100 against a radial inner side of the housing section 18 in order to seal the intermediate pressure chamber 19 in an axial direction with respect to the main axis 100, and the second seal 36 bears radially against the housing 16 in order to seal the intermediate pressure chamber 19 in an axially opposite direction with respect to the main axis 100. , wherein the fluid opening 17 is arranged axially between the two seals 35, 36 and opens into the intermediate pressure chamber 19.
[0047] The actuating device 11 also has a release bearing 37 and a pressure pot 38, which are motion-coupled to the annular piston 15 for transmitting an actuating force of the slave cylinder 12. For example, the release bearing 37 is designed as an angular contact ball bearing, which is designed and / or suitable for absorbing radial and axial forces with respect to the main axis 100.
[0048] The release bearing 37 is arranged radially inside the annular piston 15 or concentrically to the annular piston 15, wherein the release bearing 37 is supported on the one hand, e.g. with an inner ring, axially on the pressure pot 38 and on the other hand, e.g. with an outer ring, axially via an intermediate disk 39, e.g. a shim disk, on the annular piston 15.
[0049] The clutch device 30 has an outer disk carrier 40 and an inner disk carrier 41. The outer disk carrier 40 carries a plurality of outer disks 42 formed as steel disks, and the inner disk carrier 41 carries a plurality of inner disks 43 formed as friction disks, which are arranged alternately one behind the other. The outer disk carrier 40 is rotationally connected to the shaft 6, and the inner disk carrier 41 is rotationally connected to the further shaft 7.
[0050] When the master cylinder is actuated, a hydraulic column is displaced toward the slave cylinder 13, with the hydraulic fluid flowing via the pressure connection opening 20 into the intermediate pressure chamber 19 and via the fluid opening 17 into the pressure chamber 16, thereby increasing the fluid pressure in the pressure chamber 16 and applying the actuating force to the annular piston 15. The annular piston 15 is thereby moved axially to transmit the actuating force to the clutch device 30 via the release bearing 37 and the pressure pot 38, whereby the inner and outer plates 42, 43 are frictionally pressed together to close the clutch device 30.
[0051] During actuation of the slave cylinder 12, high vibrations / dynamics can occur in an oblique clutch device 30. These vibrations are reflected as a strong wobbling movement in the annular piston 15 and generate strong fluid dynamics that lead to pressure pulsations. These pressure pulsations negatively affect the entire actuation system 11 and can even lead to failure or the pressure control valve 23 no longer being able to regulate pressure. It has been shown that the pressure pulsations can be positively influenced by flow resistance. The higher the flow resistance, the greater the damping effect on the pressure pulsations.
[0052] As shown in Figures 3 and 4, a hydraulic brake 44 is therefore provided between the pressure connection 21 and the pressure chamber 16, which is designed to increase a flow resistance within the intermediate pressure chamber 19.
[0053] As shown in Figure 3, the hydraulic brake 44 is formed by a braking gap 45 formed radially between the annular housing 14 and the pressure connection opening 20, wherein the flow resistance is increased by the fact that, during the movement of the annular piston 15, a portion of the displaced hydraulic fluid or the pulsating flow is pressed via the braking gap 45 into the pressure connection opening 20. The braking gap 45 is formed by an annular gap formed at least in the region of the pressure connection opening 20, which annular gap has a reduced gap width 104 compared to the remaining intermediate pressure chamber 19 to form the braking gap 45. Put simply, the geometry of the annular housing 14 and / or the housing section 18 at the location of the pressure connection opening 20 is changed such that the intermediate pressure chamber 19 between the annular housing 14 and the housing section 18 is as small as possible in order to increase the flow resistance.For example, the brake gap 45 may have a gap width 105 of less than 3 mm.
[0054] As shown in Figure 4, the hydraulic brake 44 is formed by a cylinder bushing 46 inserted into the pressure connection opening 20, which projects partially into the intermediate pressure chamber 19. For example, the cylinder bushing 46 projects more than 50% of its total length into the intermediate pressure chamber 19 and / or is spaced from the annular housing 14 at a distance of less than 3 mm. In other words, with regard to a radial distance between the annular housing 14 and the housing section 18, the cylinder bushing 46 projects mostly or more than 50% into the intermediate pressure chamber 19. To increase the flow resistance, the cylinder bushing 46 can form an interfering contour 47 in the intermediate pressure chamber 17 and / or form or help form a braking gap 45 with respect to the annular housing 14. For example, the cylinder bushing 46 is inserted into the pressure connection opening 20 in a force-fitting manner, e.g. via a press fit.
[0055] Figures 5 and 6 show two different designs of the cylinder bushing 46. In both designs, the cylinder bushing 46 is essentially tubular or designed as a pipe section. For this purpose, the cylinder bushing 46 has a central through-opening 48 which extends the pressure connection opening 20 in the direction of the annular housing 14. To further increase the flow resistance, the through-opening 48 can have a reduced opening cross-section compared to the pressure connection opening 20. As shown in Figure 5, the cylinder bushing 46 has a circumferentially closed cylinder surface 49, so that the flow path runs exclusively via the through-opening 48 into or out of the intermediate pressure chamber 19.
[0056] Alternatively, as shown in Figure 6, the cylinder liner 46 can have a plurality of through-openings 50 opening radially into the through-opening 48, so that the flow path extends into a main flow path extending via the through-opening 48 and into or out of the intermediate pressure chamber 19 via the through-openings 50. For example, the through-openings 50 can be evenly distributed in the cylinder jacket surface 49.
[0057] List of reference symbols
[0058] Drivetrain Drive module Clutch device Prime mover Additional prime mover Shaft Additional shaft Gearbox Differential Wheels
[0059] Actuating system Actuating device Slave cylinder Ring housing Ring piston Pressure chamber Fluid opening Housing section Intermediate pressure chamber Pressure connection opening Pressure connection Pump
[0060] Pressure control valve check valve pressure side
[0061] Suction side Pressure line Suction line Fluid source Clutch arrangement Annular space Outer seal Inner seal Retaining ring First seal Second seal Release bearing Pressure pot Intermediate disc Outer disc carrier Inner disc carrier Outer discs Inner discs Hydraulic brake Brake gap Cylinder liner Through hole
[0062] Cylinder surface through openings
[0063] Rotation axis engaged end position disengaged end position actuating volume flow gap width
Claims
Patent claims 1 . Actuating device (12) for actuating a coupling device (30), - with a concentric slave cylinder (13) which has an annular piston (15) and an annular housing (14), wherein the annular piston (15) is axially movably received in an annular space (31) of the annular housing (14) which surrounds the main axis (100) and delimits the annular space (31) axially with respect to the main axis (100), so that a pressure chamber (16) which can be filled with a hydraulic fluid is formed between the annular piston (15) and the annular housing (14), - with a housing section (18), wherein the annular housing (14) is received in the housing section (18), and an intermediate pressure chamber (16) is formed radially between the annular housing (14) and the housing section (18) which surrounds the axis of rotation (100), which intermediate pressure chamber is fluidically connected, on the one hand, to the pressure chamber (16) via at least one fluid opening (17) formed in the annular housing (14) and, on the other hand, to a pressure connection (21) via a pressure connection opening (20) formed in the housing section (16); characterized in that a hydraulic brake (44) is formed between the pressure connection (21) and the pressure chamber (16) for increasing a flow resistance in the intermediate pressure chamber (19) in order to brake a pulsating flow of a hydraulic fluid displaced by the annular piston (15) during a movement of the annular piston (15).
2. Actuating device (12) according to claim 1, characterized in that the hydraulic brake (44) is formed by a brake gap (45) formed radially between the annular housing (14) and the pressure connection opening (20), wherein during the movement of the annular piston (15) a part of the displaced hydraulic fluid is pressed via the brake gap (45) into the pressure connection opening (20).
3. Actuating device (12) according to claim 2, characterized in that the intermediate pressure chamber (19) in the region of the pressure connection opening (20) is designed as an annular gap, which has a reduced gap width (105) compared to the remaining intermediate pressure chamber (19) in order to form the braking gap (45).
4. Actuating device (12) according to one of the preceding claims, characterized in that the hydraulic brake (44) is formed by a cylinder bushing (46) inserted into the pressure connection opening (20), wherein during the movement of the annular piston (15) a part of the displaced hydraulic fluid is pressed via the cylinder bushing (46) into the pressure connection opening (20).
5. Actuating device (12) according to claim 4, characterized in that the cylinder sleeve (46) projects at least partially into the intermediate pressure chamber (19), so that the cylinder sleeve (46) forms an interfering contour (47) and / or a braking gap (45) in the intermediate pressure chamber (19) to increase the flow resistance.
6. Actuating device (12) according to claim 4 or 5, characterized in that the cylinder bushing (46) has a central through-opening (48) which has a reduced opening cross-section compared to the pressure connection opening (20) in order to increase the flow resistance.
7. Actuating device (12) according to one of claims 4 to 6, characterized in that the cylinder bushing (46) has a closed cylinder surface (49).
8. Actuating device (12) according to one of claims 4 to 6, characterized in that the cylinder bush (46) has a plurality of radial passage openings (50).
9. Hydraulic actuation system (11) for a vehicle, comprising a pump (22) for generating an actuation volume flow (103) and a pressure control valve (23) connected in parallel to the pump (22) for limiting a Actuating pressure, characterized by an actuating device (12) according to one of the preceding claims, wherein the pump (29) is fluidically connected on a pressure side (32) via a pressure line (33) to the pressure connection (21) of the housing section (18).
10. Drive train (1) for a vehicle, with at least one drive machine (4, 5) for generating a drive torque and with a clutch device (30) for interrupting the drive torque, characterized by an actuating device (12) according to one of claims 1 to 8 and / or a hydraulic actuating system (11) according to claim 9.