Parking lock actuation system with double-acting actuator cylinder on the locking element and actuation method

Abstract

The invention relates to a parking lock actuation system (1) for a motor vehicle, comprising an actuation element (2) which is coupled or can be coupled to a parking lock (3) and which can be moved between a locked position, in which the parking lock (3) is activated, and an unlocked position, in which the parking lock (3) is not activated, and a locking element (4) which is designed to fix the actuation element (2) in its unlocked position in a form-fit manner, wherein the actuation element (2) and the locking element (4) are each operatively connected to a respective hydraulic actuation cylinder (5, 10), and the two hydraulic actuation cylinders (5, 10) are connected to a common hydraulic fluid supply line (9) by means of pressure chambers (27a, 27b) and are coupled to a pump (11) via a first valve (13). The actuation cylinder (5) of the locking element (4) also has an unlocking pressure chamber (8) which acts against the actuation cylinder pressure chamber (27a) and can be coupled to the pump (11) via a second valve (15). The invention also relates to a method for actuating the parking lock actuation system (1).

Description

TECHNICAL FIELD

[0001] The invention relates to a parking lock actuation system for a motor vehicle, preferably for a hybrid motor vehicle or an electric motor vehicle, comprising an actuation element which can be coupled to or is coupled to a parking lock, which can be displaced between a locked position, in which the parking lock is activated / an output member of the motor vehicle is locked against rotation, and an unlocked position, in which the parking lock is not activated / the rotation of the output member of the motor vehicle is released, and comprising a locking element which is designed to fix / hold the actuation element in the unlocked position of the actuation element in a form-fit manner. Furthermore, the invention relates to a method for actuating said parking lock actuation system. BACKGROUND

[0002] Parking lock actuation systems of the type in question are already known from the prior art. For example, DE 10 2017 102 804 A1 discloses a device and a method for actuating a parking lock.

[0003] In these designs known from the prior art, it has been found that the parking lock actuation system does indeed ensure the automatic engagement of the parking lock in principle, but not in the transport state of the motor vehicle, in which the on-board network is switched off or undercharged or the internal combustion engine is switched off and the parking lock remains engaged. The so-called limp-home function is also not possible. SUMMARY

[0004] It is therefore an object of the present invention to provide a parking lock actuation system which, independently of the charging state of the on-board network of the motor vehicle and independently of the state of the hydraulic system, implements the transport and limp-home functions of the motor vehicle in a simple manner.

[0005] According to the invention, this is achieved in that the actuation element and the locking element are each operatively connected to a hydraulic actuation cylinder, wherein both hydraulic actuation cylinders are connected on one side of the pressure chamber to a common hydraulic fluid supply line and via a first valve to a pump, and wherein the actuation cylinder of the locking element also has an unlocking pressure chamber which acts against the pressure chamber of the locking element and can be connected to the pump via a second valve.

[0006] With this double-acting actuation cylinder on the locking element, the transport state and the limp-home function of the motor vehicle can be implemented in a simple manner, while at the same time the parking lock is reliably unlocked / not activated when the hydraulic supply is de-pressurized. As a result, all other operating states of the parking lock actuation system can also be actuated easily.

[0007] Further advantageous embodiments are claimed in the dependent claims and explained in more detail below.

[0008] It is therefore also advantageous if the first valve is operatively interposed between the outlet of the pump on the one hand and the hydraulic fluid supply line on the other hand and is designed such that the first valve, in its first position, which is preferably designed as a spring-loaded rest position, depressurizes / connects the hydraulic fluid supply line to the tank, while the line section connected to the second valve is connected to the pump outlet, and the first valve, in its second position, connects the pump outlet to the hydraulic fluid supply line, while the line section connected to the second valve is separated from the pump outlet. The individual operating states of the parking lock actuation system can thus be actuated easily. The first valve is more preferably implemented as a 4 / 2-way valve in order to keep the structure of the parking lock actuation system as simple as possible.

[0009] It is furthermore advantageous if the second valve is designed such that the line section on the pump side is connected to the unlocking pressure chamber in its first position and depressurizes / connects the unlocking pressure chamber to the tank in its second position. This results in a positively actuatable coupling of the locking element to the hydraulic side. The second valve is more preferably implemented as a 5 / 2-way valve in order to keep the structure of the parking lock actuation system as simple as possible.

[0010] It is also advantageous if the second valve is designed and connected such that the line section on the pump side is connected to the hydraulic actuation unit, preferably to the clutch actuation unit, when the second valve is in the second position. The most compact system possible for supplying several components of a motor vehicle is thus designed to be operated effectively.

[0011] It is also advantageous in this case if the pump is coupled to or can be coupled to further hydraulic consumers, preferably to a gear shift element and / or to a coolant supply. The pump can then preferably be switched / actuated to supply all consumers.

[0012] It is also advantageous for a simple structure if the pump is designed as a reversible pump.

[0013] In order to actuate the actuation element easily, it is also advantageous if an electrically actuated holding magnet is provided which holds the actuation element in the unlocked position.

[0014] The invention furthermore relates to a method for actuating a parking lock actuation system according to at least one of the embodiments of the invention described above, wherein, in a first operating state, the actuation element is pressed into its unlocked position by connecting the hydraulic fluid supply line to the pump outlet and the corresponding pressure established at the pump outlet, while the locking element is spaced apart from the actuation element, and, in a second operating state, the locking element is pressed against the actuation element and engages in a form-fitting manner with the actuation element in the pressurized state of the pressure chamber of the actuation cylinder associated with the locking element.

[0015] Furthermore, if the actuating element is spring-preloaded such that, in the second operating state, in the unlocked position of the actuating element, it is pressed by this spring-preloading into a position in which the self-locking connection between the locking element and the actuating element is strengthened, and the locking element, upon a renewed drop in pressure, clamps to the actuating cylinder of the actuating element. Thus, the form-fit contact between the locking element and the actuating element is achieved in the simplest possible manner.

[0016] Further simplification of the actuation results from the fact that the form-fit between the locking element and the actuating element is cancelled again, and the locking element returns to the position of the first operating state in which the unlocking pressure chamber is pressurized via the pump until the self-locking connection between the locking element and the actuating element is cancelled.

[0017] In other words, according to the application, an actuation system for a normal P-type parking lock with additional transport function is realized by means of a double-acting latch cylinder (actuating cylinder). When the normal P-type parking lock is realized, in addition to the transport mode, a limp-home function is also realized. By means of the parallel arrangement of the locking element cylinder and the parking lock cylinder, a purely hydraulic solution for the transport mode and the limp-home function is realized. BRIEF DESCRIPTION OF DRAWINGS

[0018] The application is now explained in more detail below with reference to the drawings.

[0019] In the drawings:

[0020] Figure 1 A schematic diagram of a parking lock actuation system according to the application and according to a first exemplary embodiment is shown, in which the hydraulic connection of the actuating element and the locking element is clearly visible, and in which the actuating element and the locking element are in the normal position in which the parking lock is activated,

[0021] Figure 2 A schematic diagram of a parking lock actuation system according to the application and according to a second exemplary embodiment is shown, in which the pressure chamber of the actuating cylinder of the actuating element and the pressure chamber of the actuating cylinder of the locking element are pressurized such that the actuating element is displaced from its normal position according to the design of the application as locking position into its unlocked position, but the locking element is still arranged at a distance from the actuating element due to the filled unlocking pressure chamber, Figure 1

[0022] A schematic diagram of the parking lock actuation system of the second exemplary embodiment is shown, in which, in contrast to the first exemplary embodiment, Figure 3 Figure 2 ​In contrast, the two pressure chambers of the two actuating cylinders are de-pressurized, but the unlocking pressure chamber of the locking element is subjected to the pump pressure, so that the locking element is reliably supported at a distance from the actuating element, and wherein the holding magnet, which holds the actuating element in the unlocked position, is also activated,

[0023] Figure 4 A schematic diagram of a parking lock actuation system is shown, wherein, in contrast to Figure 3 the two pressure chambers of the two actuating cylinders and the unlocking pressure chamber of the locking element are de-pressurized, and the pump is driven so that it delivers hydraulic fluid to the two coolant and lubricant supply devices in a direction away from the actuating element and the locking element,

[0024] Figure 5 A schematic diagram of a parking lock actuation system is shown, wherein, in contrast to Figure 4 the pump delivers hydraulic fluid in the direction of a first valve, which is connected upstream of the pressure chambers of the actuating cylinders, but the first valve and the valves connected downstream of the first valve are connected so that the hydraulic fluid is directed towards the clutch actuation unit,

[0025] Figure 6 A schematic diagram of a parking lock actuation system is shown, wherein, in contrast to Figure 5 the pump and the holding magnet are both switched off, and the pressure chambers of the actuating cylinders associated with the actuating element are de-pressurized so that the actuating element is pressed back into the normal / locked position by its preloaded spring,

[0026] Figure 7 A schematic diagram of a parking lock actuation system is shown, wherein, in contrast to Figure 2 the first valve is connected so that the hydraulic fluid delivered to the pressure chambers by the pump presses the actuating element into the unlocked position of the actuating element, and the locking element presses against the actuating element so that the actuating element is finally supported in the unlocked position of the actuating element in a form-fit manner by the self-locking connection with the holding contour of the locking element, and wherein the unlocking pressure chamber is simultaneously de-pressurized,

[0027] Figure 8 A schematic diagram of a parking lock actuation system is shown, wherein, in contrast to Figure 7 the pump is switched off again and the pressure chambers are de-pressurized, but the actuating element remains in its unlocked position due to the self-locking connection with the locking element, and

[0028] Figure 9 A schematic diagram of a parking lock actuation system is shown to again illustrate the cancellation of the transport state according to Figure 8 the locking element is hydraulically pressed in the direction of the holding magnet by pressurizing its unlocking pressure chamber, so that the self-locking connection between the locking elements is cancelled, and the actuating element and the locking element are pressed into their normal position.

[0029] The drawings are essentially schematic only and serve merely to understand the application. Identical elements are provided with identical reference signs. DETAILED DESCRIPTION

[0030] Figure 1 The basic structure of the parking lock actuation system 1 according to the first exemplary embodiment of the application is clearly shown. The parking lock actuation system 1 has a hydraulic unit 23 / hydraulic side and a mechanism 24 / mechanical side. The hydraulic unit 23 is coupled to the mechanism 24 via an actuation element 2. The hydraulic unit 23 also generally has additional hydraulic consumers 16, 17, 18. The hydraulic unit 23 is driven / supplied via a single pump 11 (reversible pump). The hydraulic unit 23 is therefore considered a component of the parking lock actuation system 1 for the following considerations.

[0031] The parking lock actuation system 1 serves to actuate the parking lock 3 in a typical manner, which is shown in a simplified form in Figure 1 . In the activated position of the parking lock 3, the output components of the motor vehicle are locked, whereas the output components can be freely rotated in the non-activated position of the parking lock 3 and can therefore be driven.

[0032] The actuation element 2 of the parking lock actuation system 1 serves directly for adjusting the corresponding parking lock 3. The actuation element 2 is operatively connected to the hydraulic unit 23 via a (second) hydraulic actuation cylinder 10.

[0033] In this embodiment, in addition to the (second) actuation cylinder 10 connected to the actuation element 2, there are in the hydraulic unit 23: a first consumer 16 in the form of a clutch actuation unit 29, which comprises a slave cylinder; a second consumer 17 in the form of a coolant and lubricant supply; and a third consumer 18 also in the form of a coolant and lubricant supply Figure 1 . The other structures and operating modes of the parking lock actuation system 1 according to the application are described below with reference to the second exemplary embodiment in Figures 2 to 9 , which has the same structure as the first exemplary embodiment and only differs with respect to the non-return valve 22 of the first exemplary embodiment, which is inserted in the line section 14 described below. The following structures and operating modes of the parking lock actuation system 1 of the second exemplary embodiment therefore also apply to the parking lock actuation system 1 of the first exemplary embodiment.

[0034] The actuation element 2 is essentially realized as a piston rod and is preloaded by a preloading spring 20 into a normal position, which serves as a locked position. In this locked position, the parking lock 3 is activated Figure 1). When the second actuating cylinder 10 is subjected to hydraulic pressure, the actuating element 2 is pressed from its locked position of the actuating element against the spring force of the preloaded spring 20 into its unlocked position of the actuating element Figure 2 ). During normal driving operation of the motor vehicle, the actuating element 2 is held in the unlocked position by the holding magnet 19, which also serves as a stop. If the actuating element 2 is held in the unlocked position by the energized holding magnet 19, the hydraulic pressure on the second actuating cylinder 10 is reduced again relative to the state according to Figure 2 ) or the second actuating cylinder 10 is de-energized Figure 3 ).

[0035] In order to actuate the second actuating cylinder 10, the second actuating cylinder is / can be coupled via the first valve 13 to the pump 11 / to the outlet 12 of the pump 11. The first valve 13 is embodied as a 4 / 2-way valve. In a first position, which is shown in Figure 3 , the spring-preloaded rest position of the first valve 13, the second actuating cylinder 10, i.e. the (second) hydraulic pressure chamber 27b of the second actuating cylinder 10, is de-energized / connected to the tank 21. In a second position of the first valve 13, the pump outlet 12 is connected to the second actuating cylinder 10 according to Figure 2 . This second position corresponds to the electromagnetically activated position of the first valve 13.

[0036] According to the application, the parking lock actuation system 1 also has a locking element 4, which acts on the actuating element 2 and is also actuated / adjusted by means of the hydraulic unit 23. The locking element 4 is embodied as a bolt / pin and can be displaced laterally relative to the actuating element 2. The locking element 4 is coupled to the (first) actuating cylinder 5 of the hydraulic unit 23 and can be displaced thereby. This first actuating cylinder 5 is designed as a double-acting hydraulic actuating cylinder. Thus, the first actuating cylinder 5 has a (first) pressure chamber 27a and an unlocking pressure chamber 8 which acts against this first pressure chamber 27a. Thus, the first pressure chamber 27a, in its pressurized state, acts on the (first) piston 28a, which is coupled to the locking element 4, so that the locking element 4 is pressed in the direction of the actuating element 2. Thus, the unlocking pressure chamber 8, in its pressurized state, acts on the first piston 28a, so that the locking element 4 is pressed towards its normal position and thus into a position which is spaced apart from the actuating element 2 / from the outer side 25 of the actuating element 2.

[0037] It can also be seen that the two pressure chambers 27a and 27b are connected to a common hydraulic fluid supply line 9. Thus, the two actuating cylinders 5, 10 are connected to one another on one side of their pressure chambers 27a, 27b. This hydraulic fluid supply line 9 is then connected to the pump outlet 12 via the first valve 13.

[0038] The unlocking pressure chamber 8 is also hydraulically connected or can be hydraulically coupled to the pump outlet 12 via the second valve 15 and the first valve 13. The second valve 15 is designed as a 5 / 2 directional valve. In a first position of the second valve 15, which is implemented as a spring-preloaded rest position, the unlocking pressure chamber 8 is connected to a line section 14 which extends between the first valve 13 and the second valve 15.

[0039] In this regard, it should be noted that in the second exemplary embodiment, a check valve 22 is precisely inserted in this line section 14. The check valve 22 is inserted such that it prevents a backflow of hydraulic fluid from the unlocking pressure chamber 8 to the first valve 13 and initiates a flow of hydraulic fluid from the first valve 13 to the unlocking pressure chamber 8. In the first exemplary embodiment of Figure 1 the first exemplary embodiment of

[0040] In the second position of the second valve 15, which is illustrated in Figure 5 , the line section 14 is connected to the clutch actuation unit 29, while the unlocking pressure chamber 8 is depressurized / connected to the tank 21.

[0041] The locking element 4 serves to hold / lock the actuation element 2 in a shape- fitting manner in the unlocked position of the actuation element, preferably for implementing a transport state and a limp-home function of the motor vehicle. The locking element 4 is provided at an end facing the actuation element 2 with a holding contour 6, which can be brought into a shape-fitting engagement with the actuation element 2. The holding contour 6 can be engaged in a shape-fitting manner in a complementary recess 26 (groove) of the mobile element 2.

[0042] Figure 2 Initially, it is shown how the control element 2 enters its unlocked position during normal driving operation and is fixed by the holding magnet 19. In order to move the actuation element 2 from its locked position according to Figure 1 to its unlocked position according to Figure 2 , the pump 11 is operated in a first pumping direction such that the pump builds up a corresponding pressure at the outlet 12 facing the actuation cylinders 5, 10. By actuating / energizing the first valve 13, the first valve is switched to its second position and thus enables the pump outlet 12 to be connected to both pressure chambers 27a, 27b via the hydraulic fluid supply line 9. If the (second) piston 28b of the actuation element 2 / second actuation cylinder 10, which is connected to the actuation element 2, comes into contact with the holding magnet 19, which serves as a stop, and thus is in its unlocked position, the holding magnet 19 is opened / energized to fix the actuation element 2 in this unlocked position.

[0043] From Figure 2 and Figure 3It can also be seen that during normal driving operation, the locking element 4 is kept at a distance from the actuating element 2 in order to prevent the actuating element 2 from being locked in a form-fit manner by the locking element 4.

[0044] Depending on the current leakage in the hydraulic unit 23, the unlocking pressure chamber 8 can be exclusively connected to the pump outlet 12 and thus pressurized, as shown in Figure 3 , in order to keep the locking element 4 at a stable distance from the actuating element 2. For this purpose, in contrast to Figure 2 , the first valve 13 is brought back to its first position, so that the pressure at the pump outlet 12 reaches the unlocking pressure chamber 8 via the first valve 13 and the second valve 15. If the unlocking pressure chamber 8 is sufficiently pressurized, the non-return valve 22 Figure 4 automatically closes.

[0045] However, in principle, as indicated in Figure 2 , a relatively low leakage is also possible, and despite the pressurization of the pressure chambers 27a, 27b, the locking element 4 is kept at a distance from the actuating element 2 by means of the cushioning by the hydraulic fluid present in the unlocking pressure chamber 8.

[0046] As also shown in Figure 4 and Figure 5 , during such normal driving operation of the motor vehicle, actuation and supply of hydraulic fluid to the respective consumer 16, 17, 18 is possible depending on the pumping direction of the pump 11. In Figure 4 , the pump 11 is operated, for example, in a second pumping direction opposite the first pumping direction, and thus supplies hydraulic fluid to the second consumer 17 or the third consumer 18. In Figure 5 , the pump 11 is again operated in its first pumping direction, wherein the outlet 12 is connected to the first consumer 16 in the form of a clutch actuation unit 29 via the corresponding positions of the valves 13, 15. In this state according to Figure 5 , the first valve 13 is in its first position, while the second valve 15 is in its second position.

[0047] The implementation of such a driving operation ensures that there is a so-called normal P function, and that the parking lock 3 reliably locks / engages in the event that the holding magnet 19 is no longer energized and the pump 11 is no longer operated. The corresponding automatic closing of the parking lock 3 is shown in Figure 6 .

[0048] As can be seen in Figure 7 and Figure 8 , the locking element 4 is in form-fit engagement with the actuating element 2 in the corresponding second operating state in order to implement a transport state or limp-home function. For this purpose, depending on Figure 7, the pump 11 is operated in its first pumping direction and both valves 13, 15 each enter their second position. Both pressure chambers 27a, 27b can thus be subjected to pump pressure and the actuating element 2 and the locking element 4 can be moved from their normal position into their extended position. The locking element 4 thus engages in form-fit with the actuating element 2 and fixes the actuating element in its unlocked position.

[0049] After the state shown in Figure 7 , a state according to Figure 8 is reached, in which both valves 13, 15 are brought back into their second position and both pressure chambers 27a, 27b are depressurized compared to Figure 7 . The form-fit connection 7 between the locking element 4 and the actuating element 2 is realized as a self-locking. Thus, even if the second actuating cylinder 10 according to Figure 8 is no longer pressurized by the pump 11, the locking element 4 remains in form-fit engagement with the actuating element 2 in a self- locking manner. In this embodiment, this self-locking connection 7 is realized in principle by the corresponding friction coefficients on the retaining contour 6 and on the area of the recess 26 that is in contact with the retaining contour 6, but can also be further strengthened by additional form-fit areas. Thus, in a further embodiment according to the application, a wedge-shaped area is provided on the retaining contour 6, which is arranged and rests against the undercut of the recess 26 in such a way that the undercut of the recess is shaped in a complementary manner to the wedge-shaped area so that the locking element 4 bears in form-fit on the actuating element 2 in the longitudinal direction thereof. Since the actuating element 2 is preloaded in the direction of its normal position / locked position by the spring force of the preloading spring 20, the spring force of the preloading spring 20 has a strengthening effect on the self-locking connection 7.

[0050] According to Figure 9 , if after the actuating element 2 has been locked in its unlocked position by means of the locking element 4, the actuating element 2 is to be unlocked again / the self-locking connection 7 is to be released again, compared to Figure 8 , the unlocking pressure chamber 8 is pressurized by driving the pump 11 in the first pumping direction (and by realizing the first position of both valves 13, 15) and the locking element 4 is pressed in the direction of its normal position out of its form-fit engagement with the actuating element 2 so that the actuating element 2 is displaced into its locked position.

[0051] In other words, the parking lock actuation system 1 according to the application can be actuated as follows.

[0052] Starting from the engaged parking lock 3 (vehicle stationary), the parking lock 3 can be hydraulically disengaged, causing the (reversible) pump 11 to build pressure along the direction of the parking lock actuation cylinder 10, energizing the valve 13 and thus switching the valve so that the pump 11 is connected to the parking lock actuation cylinder 10 and simultaneously energizing the holding magnet 19. The hydraulic pressure disengages the parking lock 3 and simultaneously builds pressure in the locking pressure chamber 27a. However, since the unlocking pressure chamber 8 is not connected to the tank 21, the locking element 4 cannot move along the direction of the form-fitting element 2 and therefore will not engage. Figure 2 ).

[0053] Now switch valve 13 (de-energize). Although there is a lack of pressure in the parking lock actuating cylinder 10 at this time, the parking lock 3 remains disengaged by the retaining magnet 19. If the locking element 4 is pre-engaged due to the corresponding leakage, the locking element will disengage again at the latest at that time, because there is pressure in the unlocking chamber 8 at this time ( Figure 3 ).

[0054] If the cooling systems 17 and 18 are supplied during operation (the volumetric flow rate in the cooling circuit and the pumping direction are reversed), there is no pressure in the pressure chambers 27a and 8 of the locking cylinder 5 due to the positions of valves 13 and 15. If necessary, if the suction pressure of pump 11 is insufficient to engage the locking element 4 (pull the locking element up); Figure 4 Then the check valve 22 in the actuation line 14 ( Figure 4 ) can be omitted (according to Figure 1 ).

[0055] If the actuation unit 29 (e.g., the clutch) requests actuation, the control valve 15 is energized, causing the control valve to direct pressure in the direction of the clutch 29. Similarly, there is no pressure on the locking cylinder 5. Figure 5 ).

[0056] If a power failure occurs, pump 11 stops, both (all) valves 13 and 15 enter their de-energized normal positions (first position), and magnet 19 remains de-energized, so that parking lock 3 no longer remains disengaged. To quickly engage parking lock 3, the oil present in parking lock actuation cylinder 10 can now be directly discharged into tank 21 via valve 13. Therefore, the normal P-type function is guaranteed. Figure 6 ).

[0057] To activate the transport mode, switch valves 13 and 15. If pressure is now built up via pump 11, the parking lock actuation cylinders 10 and 27b and the locking pressure chamber 27a are pressurized, causing the parking lock 3 to disengage and the locking element 4 to engage, as pressure can be released from the unlocking pressure chamber 8 toward the tank 21. Figure 7 ).

[0058] The power supply can now be switched off (active switch-off, power failure, empty battery, etc.). All valves 13, 15 enter their normal position, the pump 11 is stopped and the holding magnet 19 remains inactive. The parking lock 3 is now, however, (passively) held disengaged by the locking element 4. Figure 8 ).

[0059] In the event of a failure of the holding magnet 19, the limp-home function can also be represented in the same way as the transport mode. The system 1, 23 is otherwise fully functional (cooling, actuation). Only the normal P function is no longer guaranteed, but is preferably displayed to the driver as an “error” together with the instruction to visit a specialist workshop. Figure 8 ).

[0060] Legend

[0061] 1 parking lock actuation system

[0062] 2 actuation element

[0063] 3 parking lock

[0064] 4 locking element

[0065] 5 first actuation cylinder

[0066] 6 holding contour

[0067] 7 connection

[0068] 8 unlocking pressure chamber

[0069] 9 hydraulic fluid supply line

[0070] 10 second actuation cylinder

[0071] 11 pump

[0072] 12 outlet

[0073] 13 first valve

[0074] 14 line section

[0075] 15 second valve

[0076] 16 first consumer

[0077] 17 second consumer

[0078] 18 third consumer

[0079] 19 holding magnet

[0080] 20 preloading spring

[0081] 21 tank

[0082] 22 check valve

[0083] 23 hydraulic unit

[0084] 24 mechanism

[0085] 25 outer side portion

[0086] 26 recessed portion

[0087] 27a first pressure chamber

[0088] 27b second pressure chamber

[0089] 28a first piston

[0090] 28b second piston

[0091] 29 clutch actuation unit

Claims

1. A parking lock actuation system (1) for a motor vehicle, the parking lock actuation system comprising: An actuating element (2) which can be coupled to or is coupled to a parking lock (3), which actuating element (2) can be displaced between a locking position, in which the parking lock (3) is activated, and an unlocking position, in which the parking lock (3) is not activated, and a locking element (4) which is designed to fix the actuating element (2) in the unlocking position of the actuating element in a form-fit manner, characterized in that the actuating element (2) and the locking element (4) are each operatively connected to a hydraulic actuating cylinder (5, 10), wherein both hydraulic actuating cylinders (5, 10) are connected on one side to a common hydraulic fluid supply line (9) and are coupled via a first valve (13) to a pump (11), and wherein the hydraulic actuating cylinder (5) of the locking element (4) also has an unlocking pressure chamber (8) which acts against the pressure chamber (27a) of the actuating cylinder and which can be coupled via a second valve (15) to the pump (11). The first valve (13) is operatively interposed between the outlet (12) of the pump (11) on the one hand and the hydraulic fluid supply line (9) on the other hand and is designed such that, in a first position of the first valve, the first valve depressurizes the hydraulic fluid supply line (9) while a line section (14) which is additionally connected to the second valve (15) is connected to the pump outlet (12), and in a second position of the first valve, the first valve connects the pump outlet (12) to the hydraulic fluid supply line (9) while the line section (14) which is additionally connected to the second valve (15) is separated from the pump outlet (12).

2. The actuation system (1) according to claim 1, characterized in that The second valve (15) is designed such that, in a first position of the second valve, the second valve connects the pump-side line section (14) to the unlocking pressure chamber (8) and, in a second position of the second valve, the second valve depressurizes the unlocking pressure chamber (8).

3. The actuation system (1) according to claim 2, characterized in that The second valve (15) is designed and connected such that, when the second valve (15) is in the second position, the pump-side line section (14) is connected to a further hydraulic actuating unit (29).

4. The actuation system (1) according to claim 3, characterized in that The pump (11) is coupled to or can be coupled to a further hydraulic consumer (16, 17, 18).

5. The actuation system (1) according to any one of claims 1 to 4, characterized in that The pump (11) is designed as a reversible pump.

6. The actuation system (1) according to any one of claims 1 to 4, characterized in that An electrically actuated holding magnet (19) is provided, which holds the actuating element (2) in the unlocking position of the actuating element.

7. The actuation system (1) according to any one of claims 1 to 4, characterized in that An electrically actuated holding magnet (19) is provided, which holds the actuating element (2) in the unlocking position of the actuating element.

8. A method for actuating a parking lock actuation system (1) according to any one of claims 2 to 4, wherein, In a first operating condition, the actuation element (2) is pressed into the unlocked position thereof by connecting the hydraulic fluid supply line (9) to the pump outlet (12) and the corresponding pressure established at the pump outlet (12), while the locking element (4) is spaced apart from the actuation element (2), and in a second operating condition, the locking element is pressed against and form-fittingly engaged with the actuation element (2) in the pressurized state of the pressure chamber (27a) of the actuation cylinder (5) associated with the locking element (4).

9. The method of claim 8, wherein, The actuation element (2) is spring-preloaded such that, in the unlocked position of the actuation element in the second operating condition, the actuation element is pressed by the spring-preloading into a position which reinforces the self-locking connection (7) between the locking element (4) and the actuation element (2), and the locking element (4) is clamped to the actuation cylinder (10) of the actuation element (2) upon pressure drop.

10. The method according to claim 8 or 9, characterized in that, The form-fitting between the locking element (4) and the actuation element (2) is cancelled and the locking element (4) returns to the position of the first operating condition in which the unlocking pressure chamber (8) is pressurized via the pump (11) until the self-locking connection (7) between the locking element (4) and the actuation element (2) is cancelled.

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