Parking lock actuation system and method for operating a parking lock actuation system

Abstract

The present disclosure relates to a parking lock actuation system (1) for a motor vehicle, comprising: - an actuation element (2) couplable to a parking lock (3) and translatable from a locking position of the actuation element to an unlocking position of the actuation element by hydraulic actuation as a result of exceeding a predetermined first pressure value; and a blocking element (4) movable from a non-blocking position of the blocking element to a blocking position of the blocking element by hydraulic actuation as a result of exceeding a predetermined second pressure value, the second pressure value being higher than the first pressure value, and the blocking element (4) being in the form of a transverse slide (7) radially movable with respect to a longitudinal axis of the actuation element (2). The present disclosure also relates to a method for operating a parking lock actuation system (1).

Description

TECHNICAL FIELD

[0001] The present invention relates to a parking lock actuation system for a motor vehicle, preferably for a hybrid or purely electric motor vehicle. The present invention also relates to a method for operating a parking lock actuation system. BACKGROUND

[0002] Such parking lock actuation systems are sufficiently known in the prior art. For example, DE 10 2017 102 804 A1 discloses a device for actuating a parking lock. However, such parking lock actuation systems have disadvantages in terms of their complexity and functionality. In particular, there is a dependency of the parking lock actuation system on the state of charge of the vehicle electrical system or on the state of the hydraulic system.

[0003] It is therefore an object of the present invention to provide a parking lock actuation system and a method for operating a parking lock actuation system which is compact and simple in design and which can optionally achieve a transport or normal P function of the motor vehicle independently of the state of charge of the vehicle electrical system and the hydraulic system. SUMMARY

[0004] The object of the present invention is achieved by a parking lock actuation system having the features of claim 1 and by a method for operating a parking lock actuation system having the features of the independent claims. Advantageous refinements form the subject matter of the dependent claims.

[0005] More precisely, the parking lock actuation system has an actuation element which can be coupled or coupled to the parking lock and which can be embodied as, for example, a plunger, a pin, etc. The actuation element can be displaced between a locked position, in which the parking lock is active, i.e. the output member of the motor vehicle is locked against rotation, and an unlocked position, in which the parking lock is inactive, i.e. the output member of the motor vehicle is released for rotation. In particular, the actuation element can be displaced along its longitudinal axis. When a predetermined first pressure value is exceeded, the actuation element can be moved into its unlocked position in a hydraulically actuated manner from its locked position. In particular, the actuation element can be displaced into its unlocked position against a return force of a (first) spring element. This means that the return force presses the actuation cylinder into its locked position in order to achieve a normal P function in normal driving operation. In other words, the actuation element is operatively connected / coupled to a (single-acting) hydraulic actuation cylinder and can thereby be displaced (into its unlocked position against a return force of a first return element) when a predetermined first pressure value is exceeded.

[0006] The parking lock actuation system also has a blocking element. The blocking element can be displaced between a blocking position and a non-blocking position. In the blocking position, the blocking element fixes the actuation element, preferably in a form-fit manner, in its unlocked position, so that the actuation element cannot be moved / back into its locked position. In the unlocked position, the locking of the actuation element is deactivated, so that the actuation element can be moved between its locked position and its unlocked position. The blocking element can be moved from its non-blocking position into its blocking position in a hydraulically actuated manner when a predetermined second pressure value is exceeded. In particular, the blocking element can be displaced into its blocking position against the resetting force of the (second) spring element. In other words, the actuation element is operatively connected / coupled to a (single-acting) hydraulic blocking cylinder and can thereby be displaced (into its blocking position against the resetting force of the second resetting element) when a predetermined second pressure value is exceeded. Here, the second pressure value is higher than the first pressure value.

[0007] According to the present disclosure, the blocking element is designed as a lateral slide which can be displaced radially / laterally with respect to the longitudinal axis of the actuation element, in particular as a plurality of lateral slides which are arranged distributed on the circumference of the parking lock actuation system. In particular, the lateral slides are moved / deflected radially outwards in the blocking position. For example, in the blocking position, the lateral slides can engage in a groove in the actuation element or in the actuation cylinder to prevent the actuation element from being moved back into its locked position in a form-fit manner. In this way, the parking lock can be kept unlocked by the blocking element in its blocking position in order to implement the transport function. In the following, the lateral slide is used synonymously for the blocking element.

[0008] In other words, the actuation element and the locking element are each operatively connected to a hydraulic cylinder, wherein the pressure chambers of the two hydraulic actuation cylinders are also connected to a common hydraulic line and are matched to one another such that the actuation element is displaced from a lower pressure value present in the hydraulic line and the actuation element is displaced from a higher pressure value present in the hydraulic line, which is higher than the lower pressure value. This coupling of the two actuation cylinders controlling the actuation element and the blocking element makes it possible for the hydraulic control of the parking lock to be constituted as simply as possible and also directly. Furthermore, the transport state of the motor vehicle can be reliably switched with simple means, so that the parking lock can be unlocked / kept deactivated when de-energized (and de-pressurized), in particular by the blocking element of the hydraulic actuation and the mechanical blocking. As a result, all other operating states of the parking lock actuation system can also be easily controlled.

[0009] Thus, the parking lock actuation system can have a first return element and a second return element, the actuation element can be displaced against a return force of the first return element in the longitudinal direction (into its unlocked position), the blocking element can be displaced / deflected against a return force of the second return element in the radial direction, e.g. outwards (into its blocking position). According to a preferred embodiment, the first return element and the second return element can be matched to each other such that the (axial) force generated by the first return element and acting on the actuation element generates a frictional force acting between the actuation element and the blocking element in the blocking position, which is greater than the return force of the second return element. This means that the blocking element in its blocking position prevents the actuation element from moving back in a form-fit manner and, when the actuation element rests against the blocking element due to the form-fit, the actuation element in turn prevents the blocking element from moving back from its blocking position using a frictional fit. In this way, the blocking element can be held in its blocking position without current or pressure.

[0010] According to a preferred embodiment, the actuation cylinder and the blocking cylinder can be matched to each other such that when the pressure is reduced from the second pressure value, the blocking element is held in its blocking position until the frictional force acts on the blocking element. The hydraulic blocking cylinder can have an auxiliary piston which can be displaced longitudinally. The hydraulic actuation cylinder can have a main piston which can be displaced longitudinally. This causes the main piston and the auxiliary piston to move back when the pressure is reduced, but the auxiliary piston moves back very slowly, so that the auxiliary piston holds the lateral slide in its deflected position until the lateral slide is held in its deflected position by the frictional force. This ensures reliable functioning of the parking lock actuation system.

[0011] According to a further refinement of the present embodiment, the blocking cylinder and the actuation cylinder can be actuated via a shared hydraulic supply. In particular, the volume flow of the hydraulic supply into (and out of) the blocking cylinder can be lower than into (and out of) the actuation cylinder. This ensures that the auxiliary piston retracts more slowly.

[0012] According to an advantageous refinement of the present embodiment, for the hydraulic supply, the blocking cylinder can be connected to the actuation cylinder via an orifice. The flow rate is reduced through the orifice and the retraction of the auxiliary piston is slowed down.

[0013] According to a preferred embodiment, the radial displacement / deflection of the blocking element can be related to the longitudinal displacement of the auxiliary piston. This means that the longitudinal displacement causes the blocking element to be displaced radially, in particular radially outwards, from its non-blocking position into its blocking position.

[0014] According to a further refinement of the preferred embodiment, the blocking element and the auxiliary piston can have corresponding surfaces which interact with one another in such a way that the blocking element is displaced in the radial direction (of the parking lock actuation system), in particular outwards, upon longitudinal displacement of the piston. For example, ramped / inclined surfaces which generate these kinematics can be provided on the blocking element and / or the auxiliary piston.

[0015] According to a refinement of the preferred embodiment, the parking lock actuation system can have a third return element against the return force of which the auxiliary piston can be displaced in the longitudinal direction for deflecting the blocking element. This means that the return force of the auxiliary piston and the lateral slide is implemented by a separate return element, so that two different return forces can be implemented. The return movement of the lateral slide is thus separated from the return movement of the auxiliary piston.

[0016] According to a further refinement of the preferred embodiment, the auxiliary piston can be designed as an annular piston which is arranged axially (and / or radially) inside the main piston. This means that the auxiliary piston is incorporated into the installation space of the main piston. In this way, a compact design is achieved.

[0017] According to the preferred embodiment, the longitudinal displacement of the actuation element into its non-blocking position can be directly related to the longitudinal displacement / deflection of the main piston. This means that the longitudinal displacement of the main piston results in the longitudinal displacement of the actuation element from its locked position to its unlocked position.

[0018] In order to facilitate the control of the actuation element, it is also advantageous if the parking lock actuation system has an electrically operated holding magnet which holds the actuation element in its unlocked position. In normal driving operation, the parking lock can be kept open without pressure by energizing the holding magnet.

[0019] The present disclosure also relates to a method of operating a parking lock actuation system for a motor vehicle. Thus, the parking lock actuation system is operated in a driving mode by applying a pressure below a predetermined (second) pressure value, and wherein the parking lock actuation system is switched from the driving mode to a transport mode by applying a pressure above the predetermined (second) pressure value. Preferably, the parking lock actuation system is switched from the transport mode to the driving mode by pressurizing below the predetermined (second) pressure level and above a lower (first) pressure level, which is lower than the predetermined (second) pressure level. In the driving mode, the de-pressurized and de-energized parking lock actuation system enables the parking lock. In the transport mode, the de-pressurized and de-energized parking lock actuation system keeps the parking lock unlocked.

[0020] In other words, the present disclosure relates to a hydraulic park lock actuation system in which a normal P function (driving mode) is implemented, i.e. the park lock is automatically activated in case of a power failure, in which a transport mode is implemented in which the park lock / park lock mechanism can be kept deactivated independently of the power supply and the hydraulic supply, i.e. in particular the park lock / park lock mechanism can be de-energized and de-pressurized and it can be regulated via a simple control valve.

[0021] In summary, the parking lock actuation system for hydraulic actuation of the parking lock is designed such that the actuation is designed to be "normally closed", such that the parking lock is automatically locked in the event of a power failure. The parking lock actuation system is actuated by a hydraulic piston (main piston), a plunger (actuation element), a (first) return spring, an electromagnet (holding magnet) and a travel sensor. During driving (in normal driving operation / driving mode), the piston is held in place (unlocked position) by the electromagnet, such that the parking lock is not blocked. In the event of a power failure, the return spring pushes the piston together with the plunger into its parking position (locked position), such that the parking lock is blocked. In order to be able to keep the parking lock unblocked for longer periods of time without current (transport mode), a mechanical holder of the plunger / piston (blocking element / lateral slide) is provided. The hydraulic actuation should be able to activate and deactivate this mechanism. For this purpose, an auxiliary piston is incorporated into the piston (main piston), which starts to move at a higher pressure level than the main piston. Thus, this displacement only occurs when the main piston is at the stop / fully extended of the main piston after the parking lock has been actuated (unlocked position). The activation pressure of the auxiliary piston is achieved by a spring bias (third return element). The return force of the auxiliary piston and the return force of the lateral slide are achieved by separate spring elements (second and third return elements), and their return movements are separate. The return force of the lateral slide is designed to be sufficient to move the lateral slide back (radially inwards). The displacement of the auxiliary piston produces one or more displacements of the lateral slide in the radial direction relative to the piston or plunger axis (longitudinal axis), for example by a ramp on the lateral slide. The radially (outwards) moving lateral slide engages in a groove located in the parking lock cylinder (actuation cylinder or other stationary component). When the pressure is released, both pistons start to move back. In order for the lateral slide to remain in the groove, the auxiliary piston must move back slowly enough, which is controlled by an orifice arranged between the auxiliary cylinder (blocking cylinder) and the main cylinder (actuation cylinder). When the lateral slide is in the groove, the piston is prevented from fully retracting and remains in place without pressure or power. In transport mode, the lateral slide is loaded axially by the force of the (first) return element of the main piston, and thus the friction force generated between the lateral slide and the main piston or the groove is greater than the return force of the lateral slide. In normal driving operation (driving mode), the parking lock is actuated at a low pressure level (below the second pressure value), such that the auxiliary piston does not move. In order to activate the transport mode, the pressure is increased to the second pressure value. In order to deactivate the transport mode again, the pressure is brought to a low pressure level (between the first and second pressure values), such that the main piston moves and the lateral slide (due to the removal of the friction force) is relieved and moves back. Thereafter, the pressure is reduced (below the first pressure value) and the main piston moves back to the parking (locked) position. BRIEF DESCRIPTION OF DRAWINGS

[0022] The application is explained below with the help of the drawings. In the drawings:

[0023] Figure 1 a schematic view of a parking lock actuation system is shown,

[0024] Figures 2 to 5 different illustrations of a parking lock actuation system are shown,

[0025] Figure 6 a relationship between pressure in a parking lock actuation system and a position of the parking lock actuation system is shown, and

[0026] Figures 7A to 7F associated longitudinal sectional views of a parking lock actuation system at selected positions according to Figure 6 a schematic view of a parking lock actuation system is shown,

[0027] The drawings are essentially schematic and are merely intended to provide an understanding of the application. Identical elements are provided with the same reference signs. Features of the various embodiments can be interchanged. DETAILED DESCRIPTION

[0028] Figure 1 a schematic view of a parking lock actuation system 1 for a motor vehicle is shown, based on which the operating modes of the parking lock actuation system 1 are described. The parking lock actuation system 1 has an actuation element 2, which can be used directly for (mechanically) adjusting a parking lock 3. The actuation element 2 can be coupled or coupled to the parking lock 3. The actuation element 2 can be particularly displaced along its longitudinal axis between a locking position and an unlocking position, as shown in Fig. 1. In the locking position, the parking lock 3 is active. In the unlocking position, the parking lock 3 is inactive. Figure 1

[0029] The parking lock actuation system 1 has a blocking element 4. The blocking element 4 can be displaced between a blocking position and a non-blocking position. In the blocking position, the blocking element 4 fixes the actuation element 2 in its unlocking position in a form-fit manner. In other words, the blocking of the actuation element 2 is active, so that the actuation element 2 cannot be moved (back) into its unlocking position. In the non-blocking position, the blocking of the actuation element 2 is inactive / unactive, so that the actuation element 2 can be moved between its locking position and its unlocking position.

[0030] The actuation element 2 is operatively connected / coupled to a (single-acting) hydraulic actuation cylinder 5 and can be displaced by this hydraulic actuation cylinder upon exceeding a predetermined first pressure value pi. This means that the actuation element 2 can be moved from its locking position, in which the parking lock 3 is active, into its unlocking position, in which the parking lock 3 is inactive, in a hydraulically actuated manner by exceeding the predetermined first pressure value pi. ​

[0031] The blocking element 4 is operatively connected / coupled to a hydraulic blocking cylinder 6 and can be displaced by this hydraulic blocking cylinder upon exceeding a predetermined second pressure value p2. This means that the blocking element 4 can be moved in a hydraulically actuated manner from its non-blocking position, in which the actuating element 2 can be moved between its locked position and its unlocked position, into its blocking position, in which the blocking element 4 fixes the actuating element 2, preferably in a form-fit manner, in its unlocked position, by exceeding the predetermined second pressure value p2. The second pressure value p2 is higher than the first pressure value p1.

[0032] In the park lock actuation system 1, the blocking element 4 is designed as a lateral slide 7, which can be displaced radially with respect to the longitudinal axis of the actuating element 2. In particular, the lateral slide 7 is moved / deflected radially outwards in the blocking position. For example, in the blocking position, the lateral slide 7 can engage in a groove 8 in the actuating element 2 or in the actuating cylinder 5 to prevent the actuating element 2 from being moved back into its locked position in a form-fit manner.

[0033] The actuating element 2 can be displaced, preferably in the longitudinal direction of the park lock actuation system 1 or of the actuating element 2, against the resetting force of a first resetting element 9. In particular, the actuating element 2 is biased into its locked position against the resetting force / release force / spring force of the first resetting element 9, in particular a spring. The blocking element 4 can be displaced, preferably in the radial direction of the park lock actuation system 1 or of the actuating element 2, against the resetting force of a second resetting element 10. In particular, the blocking element 4 is biased into its unlocked position against the resetting force / release force / spring force of the second resetting element 10, in particular a spring.

[0034] Preferably, the first resetting element 9 and the second resetting element 10 can be matched to one another such that the force generated by the first resetting element and acting on the actuating element 2 generates a frictional force acting between the actuating element 2 and the blocking element 4 in the blocking position, which is greater than the resetting force of the second resetting element 10. Thus, the actuating element 2 holds the blocking element 4 in its blocking position with a frictional fit, and the blocking element 4 holds the actuating element 2 in its unlocked position in a form-fit manner.

[0035] The longitudinal displacement of the actuating element 2 is preferably related to the longitudinal displacement of a main piston 11 of the actuating cylinder 5. The main piston 11 is preferably directly connected to the actuating element 2. In particular, when a pressure is applied to a pressure chamber of the actuating cylinder 5, the main piston is displaced axially such that the actuating element 2 is extended into its unlocked position, and when the pressure in the pressure chamber is relieved, the main piston is displaced axially (back against the resetting force of the first resetting element 9) such that the actuating element 2 is moved back into its locked position. The actuating cylinder 5 is connected to a hydraulic line / hydraulic supply 12 for supplying and / or discharging hydraulic fluid / hydraulic medium.

[0036] The radial displacement / deflection of the blocking element 4 is preferably associated with a longitudinal displacement of the auxiliary piston 13 of the blocking cylinder 6. This means that the blocking element 4 can be displaced into its blocking position by the longitudinal displacement of the auxiliary piston 13 against the restoring force of the second restoring element 10. In particular, when pressure is applied to the pressure chamber of the blocking cylinder 6, the auxiliary piston is displaced axially such that the blocking element 4 / transverse slide 7 extends radially outwards into its blocking position, and when the pressure in the pressure chamber is relieved, the auxiliary piston is displaced axially back against the restoring force of the third restoring element 14 such that the blocking element 4 / transverse slide 7 moves radially inwards back into its unlocking position against the restoring force of the second restoring element 10. The blocking cylinder 6 is connected to a hydraulic line / hydraulic supply 12 for supplying and / or discharging hydraulic fluid / hydraulic medium.

[0037] The hydraulic port 15 can preferably be arranged in a section of the hydraulic line 12 through which hydraulic fluid can be conducted into and / or out of the blocking cylinder 6. This means that the flow cross section or volume flow of the hydraulic supply of the blocking cylinder 6 is smaller than the flow cross section or volume flow of the hydraulic supply of the actuating cylinder 6. As a result, the hydraulic fluid flows into and / or out of the hydraulic cylinder 5 faster than into and / or out of the blocking cylinder 6. As a result, the auxiliary piston 13 retracts more slowly.

[0038] Furthermore, the parking lock actuation system 1 preferably has a holding magnet 16, which can be energized (during normal driving operation of the motor vehicle) to hold the actuating element 2 in its unlocked position.

[0039] Figures 2 to 5 Different illustrations of the parking lock actuation system 1 are shown, on the basis of which advantageous structural configurations are described.

[0040] The actuating cylinder 5 forms a parking lock cylinder in which the hydraulic and mechanical actuation of the parking lock actuation system 1 is arranged. By pressurizing the pressure chamber of the actuating cylinder 5, the main piston 11 is deflected axially (displaced relative to the inner wall of the actuating cylinder 5). The main piston 11 is biased axially by the first restoring spring 9. The first restoring spring 9 is arranged radially between the actuating element 2 and the auxiliary piston 11 and / or the blocking element 4 / transverse slide 7. The holding magnet 16 serves as an axial stop for the deflection of the main piston 11.

[0041] The blocking cylinder 6 is formed by the main piston 11. The auxiliary piston 13 is designed as an annular piston which is axially and / or radially incorporated inside the main piston 11. When the main piston 11 is axially deflected, the auxiliary piston 13 is also deflected. By pressurizing the pressure chamber of the blocking cylinder 6, the auxiliary piston 13 is axially deflected (shifted relative to the inner wall of the blocking cylinder 6 or relative to the main piston 11). The pressure chamber of the blocking cylinder 6 is connected to the pressure chamber of the actuating cylinder 5 via the diaphragm 15. The auxiliary piston 13 is axially biased by a third return spring 14. The third return spring 14 is arranged radially between the actuating element 2 or the first return spring 9 and the blocking element 4 / transverse slide 7. The third return spring 14 is axially clamped between the auxiliary piston 11 and a component which is firmly connected to the actuating element 2 or the main piston 11.

[0042] The auxiliary piston 11 is axially pressed against the transverse slide 7 as a result of the axial deflection. The transverse slide 7 has a ramp / inclined surface 17, so that the transverse slide is pressed / shifted / deflected radially outwards by the auxiliary piston 11 against the return force of the second return element 10, here a spring ring, in the event of an axial deflection. In a deflected position which corresponds to the blocking position of the transverse slide 7, the transverse slide 7 is engaged in a groove 8 formed in the inner wall of the actuating cylinder 5. The radial displacement of the transverse slide 7 is guided by a slide sleeve 18. If the transverse slide 7 is in the deflected position, i.e. if the blocking element 4 is in the blocking position, the transverse slide 7 forms a spacer for the actuating element 2 or the component connected to the actuating element. In the embodiment shown, a contact plate 19 which is firmly connected to the main piston 11 rests against the transverse slide 7 and axially presses the transverse slide against the inner wall of the groove 8 by means of the return force of the first return spring 9. This axial force of the contact plate 19 generates a frictional force which is greater than the return force of the second return element 10 and thus prevents the transverse slide 7 from moving back. If the transverse slide 7 is not deflected, the main piston 11 and thus the actuating element 2 can be moved back into its locked position.

[0043] Figure 6 A graph is shown in which the relationship between the hydraulic pressure 20 present in the hydraulic line 12, the actuating element deflection 21, the auxiliary piston deflection 22 and the blocking element deflection 22 is plotted. Figures 7A to 7F The associated positions of the parking lock actuation system 1 at different points in time I to VI according to Figure 6 are shown in longitudinal section. These positions are described in more detail below.

[0044] At time I (see Figure 7A), the hydraulic pressure corresponds to the first pressure value pi. The main piston 13 is completely axially deflected and the actuating element 2 remains in its unlocked position. The actuating element 2 (for normal driving) can remain in this unlocked position without pressure by energizing the retaining magnet 16. This pressure is below the second pressure value p2, so that the auxiliary piston 13 and the lateral slide 7 are not deflected. The blocking element 4 is in its non-blocking position.

[0045] The auxiliary piston 13 is activated between time I and time II. To this end, the hydraulic pressure is increased to the second pressure value p2. The auxiliary piston 13 is axially deflected until it rests against the contact plate 19. Due to the axial deflection of the auxiliary piston 13, the lateral slide 7 is radially deflected until it engages in the groove 8.

[0046] At time II (see Figure 7B ), the hydraulic pressure corresponds to the second pressure value p2. The main piston 13 remains completely axially deflected and the actuating element 2 remains in its unlocked position. The auxiliary piston 13 is kept deflected by the hydraulic pressure. The lateral slide 7 is kept deflected in its locked position by the auxiliary piston 13. The transport mode is activated / occupied.

[0047] The hydraulic pressure is reduced between time II and time III. The main piston 11 and the actuating element 2 move axially back until they (or the contact plate 19) rest against the lateral slide 7 / prevent them from moving further back in a form-fit manner. The auxiliary piston 13 moves axially back, but more slowly than the main piston 11, so that the lateral slide 7 is kept deflected by the auxiliary piston 13 until the main piston 11 (or the contact plate 19) rests against the lateral slide 7. The actuating element 2 is in its unlocked position. The blocking element 4 is in its blocking position.

[0048] At time III (see Figure 7C ), the hydraulic pressure is below the first pressure value pi. The main piston 11 (or the contact plate 19) is axially supported against the lateral slide 7 and form-fittingly prevented from moving back into the locked position of the actuating element 2. The auxiliary piston 13 continues to move axially back and no longer pushes the lateral slide 7 outwards. The lateral slide 7 is kept radially deflected by frictional forces that are generated on the lateral slide 7 by the return force acting axially on the main piston 11 or the actuating element. The actuating element 2 is in its unlocked position. The blocking element 4 is in its blocking position.

[0049] At time IV (see Figure 7D ), the hydraulic pressure is increased. The hydraulic pressure is below the first pressure value pi. The auxiliary piston 13 is completely retracted. The actuating element 2 is in its unlocked position. The blocking element 4 is in its blocking position.

[0050] At time V (seeFigure 7E ), the hydraulic pressure corresponds to the first pressure value pi. The main piston 11 starts to axially deflect and the contact plate 19 starts to axially disengage from the lateral slide 7.

[0051] At time VI (see Figure 7F ), the hydraulic pressure corresponds to the first pressure value pi. The main piston 11 is completely axially extended. The contact plate 19 is no longer in contact with the lateral slide 7 or no longer axially presses the lateral slide into the groove 8. The lateral slide 7 is radially retracted by the second return element 10, since no frictional force acts on this lateral slide. The transport mode is deactivated / disabled. When the hydraulic pressure drops below the first pressure value pi, the main piston 11 will move back into its completely retracted position and the actuation element 2 will move into its blocking position.

[0052] List of reference signs

[0053] 1 parking lock actuation system

[0054] 2 actuation element

[0055] 3 parking lock

[0056] 4 blocking element

[0057] 5 actuation cylinder

[0058] 6 blocking cylinder

[0059] 7 lateral slide

[0060] 8 groove

[0061] 9 first return element

[0062] 10 second return element

[0063] 11 main piston

[0064] 12 hydraulic line

[0065] 13 auxiliary piston

[0066] 14 third return element

[0067] 15 orifice

[0068] 16 holding magnet

[0069] 17 ramp

[0070] 18 sliding sleeve

[0071] 19 contact plate

[0072] 20 hydraulic pressure

[0073] 21 actuation element deflection

[0074] 22 auxiliary piston deflection

[0075] 23 blocking element deflection

Claims

1. A parking lock actuation system (1) for a motor vehicle, having an actuation element (2) which can be coupled to a parking lock (3) and which can be translated by hydraulic actuation from a locking position of the actuation element, in which the parking lock (3) is active, to an unlocking position of the actuation element, in which the parking lock (3) is inactive, as a result of a predetermined first pressure value (pi) being exceeded, and having a blocking element (4) which can be moved by hydraulic actuation from a non-blocking position of the blocking element, in which the actuation element (2) can be moved between the locking position of the actuation element and the unlocking position of the actuation element, to a blocking position of the blocking element, in which the blocking element (4) fixes the actuation element (2) in the unlocking position of the actuation element in a form-fit manner, as a result of a predetermined second pressure value (p2) being exceeded, wherein The second pressure value (p2) is higher than the first pressure value (p1), characterized in that the blocking element (4) is in the form of a lateral slide (7) which can be moved radially with respect to the longitudinal axis of the actuating element (2), the actuating element (2) being connected to an actuating cylinder (5) for actuation of the actuating element, and the blocking element (4) being connected to a blocking cylinder (6) for actuation of the blocking element, the blocking cylinder (6) and the actuating cylinder (5) being able to be actuated via a shared hydraulic supply (12).

2. The actuation system (1) according to claim 1, characterized in that a first reset element (9) and a second reset element (10), the actuating element (2) being able to be translated in the longitudinal direction against a reset force of the first reset element, the blocking element (4) being able to be moved in the radial direction against a reset force of the second reset element, wherein the first reset element (9) and the second reset element (10) are matched to one another such that a force generated by the first reset element and acting on the actuating element (2) generates a friction force which acts between the actuating element (2) and the blocking element (4) in the blocking position and which is greater than the reset force of the second reset element (10).

3. The actuation system (1) according to claim 2, characterized in that The actuating cylinder (5) and the blocking cylinder (6) are matched such that when the pressure decreases from the second pressure value, the blocking element (4) is held in its blocking position until the friction force acts on the blocking element (4).

4. The actuation system (1) according to claim 3, characterized in that The volume flow of the hydraulic supply (12) into the blocking cylinder (6) is less than the volume flow into the actuating cylinder (5).

5. The actuation system (1) according to claim 4, characterized in that For hydraulic supply, the blocking cylinder (6) is connected to the actuating cylinder (5) via an orifice (15).

6. The actuation system (1) according to any one of claims 3 to 5, characterized in that The blocking cylinder (6) has an auxiliary piston (13) which can be displaced longitudinally, wherein the radial displacement of the blocking element (4) into its blocking position is related to the longitudinal displacement of the auxiliary piston (13), and / or the actuating cylinder (5) has a main piston (11) which can be displaced longitudinally, wherein the longitudinal displacement of the actuating element (2) is related to the longitudinal displacement of the main piston (11).

7. The actuation system (1) according to claim 6, characterized in that The blocking element (4) and the auxiliary piston (13) have corresponding surfaces which interact with one another such that the blocking element (4) is displaced in the radial direction when the auxiliary piston (13) is displaced longitudinally.

8. The actuation system (1) according to claim 6, characterized in that a third reset element (14), the auxiliary piston (13) being able to be translated in the longitudinal direction against a reset force of the third reset element in order to deflect the blocking element.

9. The actuation system (1) according to claim 6, characterized in that The auxiliary piston (13) is designed as an annular piston which is arranged axially inside the main piston (11).

10. A parking lock actuation system (1) for a motor vehicle, having an actuation element (2) which can be coupled to a parking lock (3) and which can be translated by hydraulic actuation from a locking position of the actuation element, in which the parking lock (3) is active, to an unlocking position of the actuation element, in which the parking lock (3) is inactive, as a result of a predetermined first pressure value (pi) being exceeded, and having a blocking element (4) which can be moved by hydraulic actuation from a non-blocking position of the blocking element, in which the actuation element (2) can be moved between the locking position of the actuation element and the unlocking position of the actuation element, to a blocking position of the blocking element, in which the blocking element (4) fixes the actuation element (2) in the unlocking position of the actuation element in a form-fit manner, as a result of a predetermined second pressure value (p2) being exceeded, wherein said second pressure value (p2) is higher than said first pressure value (p1), characterized in that said blocking element (4) is in the form of a transverse slide (7) radially movable with respect to the longitudinal axis of said actuation element (2), said actuation element (2) being connected to an actuation cylinder (5) for the actuation of said actuation element, and said blocking element (4) being connected to a blocking cylinder (6) for the actuation of said blocking element, said blocking cylinder (6) having an auxiliary piston (13) longitudinally displaceable, said actuation cylinder (5) having a main piston (11) longitudinally displaceable, said auxiliary piston (13) being designed as an annular piston axially arranged inside said main piston (11).

11. The actuation system (1) according to claim 10, characterized in that said blocking cylinder (6) and said actuation cylinder (5) are actuatable via a common hydraulic supply (12), the volumetric flow rate into said blocking cylinder (6) being lower than the volumetric flow rate into said actuation cylinder (5), said blocking cylinder (6) being connected to said actuation cylinder (5) via an orifice (15) for the hydraulic supply.

12. A method for operating a parking lock actuation system (1) for a motor vehicle according to any one of claims 1 to 11, wherein, said parking lock actuation system (1) is operated in a driving mode by applying a pressure lower than a second pressure value (p2), and wherein said parking lock actuation system (1) is switched from said driving mode to a transport mode by applying a pressure higher than said second pressure value (p2).

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