Vehicle braking system

Abstract

The invention relates to a vehicle braking system with at least one multi-disc brake or clutch (3) acting on a vehicle axle and an electrically controllable actuator (21) by which a braking function for vehicle braking during driving and a parking function when the vehicle is parked can be engaged / disengaged in the multi-disc brake or clutch (3). According to the invention, the vehicle braking system additionally has a parking lock (41) whose pawl (43) can be brought into locking engagement with a locking gear (45) when the parking function is engaged.

Description

[0001] The invention relates to a vehicle braking system according to the preamble of claim 1.

[0002] A vehicle braking system of this type features, instead of conventional disc or drum brakes, at least one multi-disc brake acting on the vehicle axle. This brake allows for the activation or deactivation of a braking function for vehicle braking while driving or a parking function when the vehicle is parked. For this purpose, the multi-disc brake has two independently operating actuators: a brake actuator and a parking actuator. These are controlled by a control unit using electrical or hydraulic signals. For safety reasons, the brake actuator can be designed to be normally open (non-self-locking), while the parking actuator can be normally closed (self-locking). Integrating these two actuators into the multi-disc brake requires installation space and involves additional design effort.

[0003] DE 10 2014 102 831 A1 discloses a parking lock arrangement with a pawl and a cooperating locking gear. When the parking function is engaged, the pawl can be brought into locking engagement with the locking gear. EP 3 428 021 A1 discloses another parking lock arrangement that can be actuated by an electric motor.

[0004] The object of the invention is to provide a vehicle braking system that can be implemented with reduced installation space and reduced design effort compared to the prior art.

[0005] The problem is solved by the features of claim 1. Preferred embodiments of the invention are disclosed in the dependent claims.

[0006] The invention relates to a vehicle braking system with at least one multi-disc brake or clutch acting on a vehicle axle, by means of which a braking function for vehicle braking during driving and a parking function when the vehicle is parked can be engaged / disengaged. Exactly one electrically controlled actuator is assigned to the multi-disc brake or clutch. The actuator can be used to engage / disengage both the braking function and, alternatively, the parking function. This results in a simplified braking concept compared to the prior art, with regard to cost, installation space, and component weight. For safety reasons, the electrically controlled actuator is normally open (i.e., not self-locking) when the braking function is engaged, while it is normally closed (i.e., self-locking) when the parking function is engaged.

[0007] According to the characterizing part of claim 1, the following measure is taken to increase functional reliability: The vehicle braking system additionally features a parking lock, the pawl of which can be engaged with a locking gear when the parking function is activated. The parking lock thus supports the parking function activated by the electrically controlled actuator. According to the invention, the parking function is therefore implemented not only by the electrically controlled actuator but also by the parking lock. The requirements for the electrically controlled actuator with regard to holding torque are therefore reduced compared to a vehicle braking system that does not have a parking lock.

[0008] In a technical implementation, the actuator can include at least one ball ramp unit. This unit allows the multi-disc brake or clutch to be subjected to contact pressure when the braking or parking function is engaged. Conversely, the multi-disc brake or clutch can be relieved of pressure when the braking or parking function is disengaged. The ball ramp unit consists of a pair of discs: one stationary and one rotatable coaxially. The ball can roll between the discs' inclined, facing brake ball tracks.

[0009] The braking function can be engaged as follows: An electric rotary drive (i.e., a spindle drive) of the actuator adjusts the rotatable disc from a neutral position in a braking direction by a braking angle into a braking range. This causes the ball to roll along the brake ball tracks, with the disc pair being axially spread over a specific axial path. In this way, the multi-disc brake / clutch is subjected to a contact pressure. This pressure varies depending on the size of the braking angle.

[0010] When the braking function is engaged, rolling resistance acts between the ball and the brake ball tracks of the disc pair. The low rolling resistance compared to a sliding system means that the ball-ramp unit is not self-locking, i.e., it remains open when de-energized. Therefore, in the event of a power failure, the actuator's braking effect automatically cancels out, thus fulfilling safety requirements.

[0011] Conversely, the clamping mechanism according to the invention is designed such that when the parking function is engaged, the actuator is self-locking, i.e., closed when de-energized. Therefore, in the event of a power failure, the parking function – unlike the braking function – is permanently maintained, so that the parking function also meets safety requirements.

[0012] The braking and parking functions can be implemented as follows: The ball-ramp unit can have corresponding, inclined sliding ramps. These are formed on both discs and can be brought into sliding contact with each other. To engage the parking function, the electric rotary drive (i.e., the spindle drive) of the actuator moves the rotatable disc from its neutral position in a parking direction opposite to the braking direction, through a parking rotation angle into a parking position. In the parking position, the sliding ramps of the two discs come into sliding contact, with the disc pair being axially spread by the axial spreading distance, thereby exerting a contact pressure on the multi-disc brake / clutch.

[0013] When the parking function is engaged, a sliding resistance acts between the corresponding sliding ramps of the discs. This is significantly greater than the rolling resistance between the ball and the brake ball tracks of the disc pair. Therefore, when the parking function is engaged, the ball-ramp unit is self-locking (unlike in the braking function), meaning it remains closed when de-energized. Thus, when the parking function is engaged, the braking effect can be maintained even in the event of a power failure.

[0014] To ensure reliable engagement of the parking function, the following measure is preferred: The parking position can be divided into a first section and a second section following the direction of rotation in the parking direction. In the first section, the ball can roll between the opposing parking ball tracks of the disc pair. In contrast, in the second section, the ball is out of contact with the disc pair. To engage the parking function, the rotating disc is moved from its neutral position in the direction of rotation by a parking angle into the first section until a transition point is reached. During this movement in the first section, the ball rolls along the parking ball tracks of the disc pair. This occurs with axial spreading of the disc pair over a specific axial spreading path. In this way, any play in the multi-disc brake / clutch is eliminated.Once the transfer point is exceeded, the rotating disc is adjusted in the second section with a continuously increasing parking rotation angle until the parking function is engaged.

[0015] During the adjustment process in the first section, the sliding surfaces of the two discs remain outside the sliding contact area. Only when the transition point is exceeded do the two sliding surfaces come into sliding contact with each other, while at the same time the ball comes out of rolling contact with the pair of discs.

[0016] The inclination angle of the two sliding ramps is preferably greater than the inclination angle of the parking ball tracks. This ensures that when the ball passes the transfer point, it reliably lifts off the parking ball tracks of the disc pair, meaning the ball is no longer in contact with the parking ball tracks. With the parking function engaged, this ensures that only the sliding resistance of the corresponding sliding ramps acts between the discs.

[0017] The parking ball tracks and the braking ball tracks can merge into each other at a ramp recess in the circumferential direction of the disc. This defines the zero rotation position. The parking ball tracks can be designed as mirror images of the braking ball tracks with respect to the symmetry provided by the ramp recess. Starting from the zero rotation position, as the braking or parking rotation angle increases, the free play of the multi-disc brake / clutch is first eliminated. Subsequently, a kiss point is reached at which the multi-disc brake / clutch transmits a measurable or predefined torque. For reliable engagement of the parking function, it is preferred that the transition point is crossed shortly before reaching the kiss point within the parking range.

[0018] Operational reliability is further increased if, when the parking function is engaged, the ball (after lifting off the two parking ball tracks) remains in a predefined free-rolling position. In this free-rolling position, the ball can roll freely between the parking ball tracks of the disc pair, without any rolling contact.

[0019] The predefined ball freewheel position can be achieved, for example, as follows: Each of the parking ball tracks of the two discs, viewed in the direction of rotation during parking, can end at a ball track outlet that forms a ball movement stop. When the parking function is engaged, the two ball track outlets, viewed in the circumferential direction of the disc, can be spaced apart by a ball freewheel, which defines the ball freewheel position. When the parking function is disengaged, the rotating disc is moved in the opposite direction of rotation to the zero rotation position.

[0020] By providing the ball freewheel position, it is ensured that the ball comes into rolling contact with the parking ball tracks at least approximately at the transfer point and that the ball is in the ramp recess when it reaches the zero rotation position.

[0021] A key aspect of the invention is that the electrically controlled actuator not only controls the pressure mechanism acting on the multi-plate brake or clutch, but also additionally controls the pawl of the parking lock between a locking position, in which the pawl can be brought into locking engagement with the locking gear, and a release position, in which the pawl is out of locking engagement with the locking gear.

[0022] For simple pawl actuation, the rotating disc of the disc pair is mechanically connected to the pawl. This connection is designed so that when the rotating disc is turned into the park position, the pawl automatically engages. Conversely, when the rotating disc is turned from the park position into the brake position, the pawl automatically engages.

[0023] In one specific embodiment, the vehicle axle can have an axle differential. Its output sides drive to the vehicle wheels via output shafts. A multi-plate brake or clutch is arranged on each output side, acting on the respective output shaft. The locking gear of the parking lock can, for example, be fixed to a differential housing of the axle differential. In this configuration, the parking lock is positioned at an axial distance from the respective multi-plate brake or clutch.

[0024] The drive connection formed between the rotatable disc and the pawl can be implemented in a structurally simple manner as follows: A control lever and the pawl axially spaced from it can be fixed to a parking lock shaft. The control lever can be in sliding contact with a control contour formed on the rotatable disc, particularly under spring preload.

[0025] An embodiment of the invention is described below with reference to the accompanying figures.

[0026] They show: Fig. 1 to 11 different views, by means of which the structure and the function of the vehicle braking system according to the invention are described.

[0027] In the Fig. Figure 1 shows an electrified vehicle axle with an electric motor EM and a gearbox. The electric motor EM is connected to a high-voltage battery (not shown). Conventional wheel disc or drum brakes are omitted from the vehicle axle. Instead of such conventional wheel brakes, the vehicle axle has multi-disc brakes 3, by means of which vehicle braking can be performed. In addition, the vehicle axle has a [missing information - likely a component or component] in the Fig. 1 or Fig. 2 parking barriers 41 (not shown), the structure and function of which will be explained later using the Fig. is described in sections 9 to 11.

[0028] The electric machine EM is connected via its rotor shaft 5 and an intermediate reduction stage 7 to the input side of an axle differential 9. The output sides of the differential are driven by output shafts 11 and connected to the vehicle wheels. In the Fig. 1 The electric motor EM is installed transversely in the vehicle axle. Accordingly, the rotor shaft 5 and the output shafts 11 are parallel to each other. Likewise, the multi-disc brakes 3 installed in the vehicle axle are aligned parallel to each other in the transverse direction y of the vehicle.

[0029] Viewed in the transverse direction y of the vehicle, the axle has one of the multi-disc brakes 3 on each side of the vehicle. These can be controlled by an electronic control unit (not shown) to perform uniform or uneven braking at both vehicle wheels.

[0030] The reduction gear stage 7 is driven by an input-side axle differential gear 13. The axle differential gear 13 is rotationally fixed to a rotating differential housing 15. According to the Fig. 1 drives the axle differential 9 with the multi-plate brakes 3 open in the transverse direction y of the vehicle in a 50 / 50 distribution on both sides to the two output shafts 11 leading to the vehicle wheels.

[0031] In the Fig. 1. The two multi-disc brakes 3 act directly on the output shafts 11. This means that the inner disc carrier 18 of the multi-disc brake 3 is connected to the respective output shaft 11, while the outer disc carrier 17 is fixed to a gearbox housing wall 19. The disc assembly located between the outer disc carrier 17 and the inner disc carrier 18 can be subjected to contact pressure via an actuator 21. The actuator 21 can be controlled by the control unit by means of electrical signals.

[0032] Actuator 21 is in the Fig. Figures 2 to 3c illustrate this. It consists of a spindle drive (not shown) with an electric motor, which is driven by a toothed section 31 of a rotatable disc 27. The non-rotating disc 25 can be supported circumferentially by an indicated torque support 14. Furthermore, the non-rotating disc 25 is supported axially on a counter support 12. The rotatable disc 27, together with a non-rotating disc 25, forms part of a clamping mechanism with a total of four circumferentially distributed ball-ramp units 23, as shown in the figures. Fig. 3a to 3b. Each ball-ramp unit 23 has a ball 29 that rolls between the two disks 25, 27.

[0033] The lamellar assembly located between the outer lamella carrier 39 and the inner lamella carrier can be subjected to contact pressure by means of the actuator 21. Depending on the control of the actuator 21, a braking function for vehicle braking while driving, or alternatively a parking function when the vehicle is parked, can be engaged or disengaged. A key aspect of the invention is that both the braking function and the parking function can be engaged / disengaged by means of the actuator 21. For safety reasons, the electrically controlled actuator 21 is normally open (i.e., not self-locking) when the braking function is engaged. In contrast, the electrically controlled actuator 21 is normally closed (i.e., self-locking) when the parking function is engaged.

[0034] As from the Fig. As can be seen from Figures 3a to 3c, each of the ball-ramp units 23 has ball ramps 34 and spaced-apart sliding ramps 38 that act between the disks 25, 27. The balls 29 of the four ball-ramp units 23 are, according to the Fig. 3b was led into a cage 30. In the Fig. 4a and Fig. 4b is one of the ball-ramp units 23, each shown in unfolded form. Fig. Figure 4a shows two corresponding sliding ramps 38 of the disk pair, while Fig. Figure 4b shows two corresponding ball ramps 34 of the disc pair with an intermediate ball 29. Each of the ball ramps 34 consists of a braking ball track 35 and a parking ball track 37, which merge into each other at a ramp depression 39. In the Fig. 4a The ball 29 is located in the ramp recess 39. The ramp recess 39 defines a zero rotation position 0, in which the pair of discs exerts no contact pressure on the lamellar assembly. The ball ramps 34 of the two discs 25, 27 are point-symmetrical with respect to the ball 29. In addition, the parking ball track 37 and the braking ball track 35 of each ball ramp 34 are symmetrical with respect to an axis of symmetry passing through the ramp recess 39, with equal angles of inclination.

[0035] A key aspect of the invention is that, depending on a direction of rotation D B , D PThe rotatable disc 27 can be configured to either engage or disengage a braking function for vehicle braking while driving, or alternatively, a parking function when the vehicle is parked. An important aspect of the invention is that the disc pair of the actuator 21 is open when de-energized, i.e., not self-locking, when the braking function is engaged. In contrast, the disc pair of the actuator 21 is closed when de-energized, i.e., self-locking, when the parking function is engaged.

[0036] In the Fig. 4a and Fig. Figure 4b shows the pair of discs in their zero rotation position 0. In the zero rotation position 0 (unlike in the Fig. (as shown in 4a) the two sliding ramps 38 are out of contact. The ball 29 is located according to the Fig. 4b in the ramp recesses 39 of the ball ramps 34 of the two discs 25, 27.

[0037] The following will be based on the Fig. Sections 5a to 6b initially describe how to engage the brake function. Starting from the point described in the Fig. 4a and Fig. In the zero position shown in 4b, the rotatable disc 27 is turned in a braking direction D. B via a brake rotation angle to the left into a brake adjustment range S B The ball 29 rolls on the two brake ball tracks 35 of the disc pair, with the disc pair being axially spread over an axial spreading path s. In this way, the lamellar pack of the multi-disc brake 3 is subjected to contact pressure. The contact pressure varies depending on the size of the brake rotation angle. Immediately after leaving the zero rotation position 0, the rotatable disc 27 is adjusted by an axial spreading path s, thereby eliminating any play in the lamellar pack. Further rotational adjustment of the rotatable disc 27 within the brake adjustment range S... B A Kisspoint KP ( Fig. 5b) is achieved, in which the multi-disc brake 3 transmits a measurable, predefined torque. In the Kisspoint KP, the rotatable disc 27 (starting from the zero rotation position 0) is rotated by a first axial spreading path Δs1. In the Fig. 6a and Fig. 6b the rotatable disk 27 is adjusted to an end position in which the rotatable disk 27 is adjusted by a second axial spreading path Δs2.

[0038] When the braking function is engaged, a comparatively low rolling resistance acts between the ball 29 and the brake ball tracks 35 of the disc pair. This low rolling resistance means that the ball-ramp units 23 are not self-locking, i.e., they are open when de-energized. Accordingly, in the event of a power failure, the braking effect of the actuated actuator 21 would decrease, thus fulfilling safety requirements.

[0039] To implement the brake function, the rotatable disc 27 (starting from its end position ( Fig. 6a and Fig. 6b) opposite to the direction of braking rotation D B back to the zero rotation position 0 ( Fig. 4a and Fig. 4b) adjusted.

[0040] During the adjustment movement in the brake adjustment range S B The corresponding, inclined sliding ramps 38 remain out of contact with each other, so that smooth rotation of the rotatable disc 27 is ensured.

[0041] Based on the Fig. Sections 7a to 8b below describe how to engage the parking function. Starting from the position shown in the Fig. 4a and Fig. In the zero position shown in 4b, the rotatable disc 27 is used to engage the parking function in a direction of rotation D relative to the brake direction. B opposite parking direction D P via a parking swivel angle into a parking space S P twisted to the right.

[0042] According to the Fig. 7b is parking area S Psubdivided into a first sub-area S P1 and into a second sub-area S P2 In the first sub-area S P1 The ball 29 rolls between the facing parking ball tracks 37 of the pair of discs, while the corresponding sliding ramps 38 are still out of contact. In contrast, in the second sub-area S P2 The sliding surfaces 38 are in sliding contact with each other, while the ball 29 is out of rolling contact with the disc pair. To engage the parking function, the rotatable disc 27 is rotated from the zero position 0 in the parking direction D. P to a parking rotation angle in the first sub-area S P1 until reaching a transfer point U, as described in the Fig. 7a and Fig. 7b is indicated. According to the Fig. 7a and Fig. 7b generates a third axial spreading path Δs3 at the transfer point U of the disk pair.

[0043] During the adjustment movement in the first sub-area S P1 The ball 29 rolls along the parking ball tracks 37 of the disc pair, with axial spreading of the disc pair, thus eliminating any play in the lamellar brake 3. Upon passing the transfer point U, the rotatable disc 27, with a further increasing parking rotation angle, moves into the second sub-area S. P2 twisted until the parking function is engaged.

[0044] With regard to ensuring reliable engagement of the parking function, the parking space S PThe transfer point U is positioned between the rotation zero position 0 and the kiss point KP. When the parking function is engaged, the transfer point U is therefore passed shortly before reaching the kiss point KP. Upon reaching the kiss point KP, the two corresponding sliding ramps 38 are already in sliding contact with each other, while the ball 29 is out of rolling contact with the two parking ball tracks 37.

[0045] In the Fig. 8a and Fig. 8b the rotatable disc 27 is rotated to its park end position, in which the park function is fully engaged. In the engaged park function, the ball 29 is in a predefined ball freewheel position P ( Fig. 8b). The ball freewheel position P is in the Fig. 8b is defined by means of ball track outlets 41 of the parking ball tracks 37. When the parking function is engaged, the ball track outlets 41 are spaced apart from each other in the circumferential direction of the discs by a ball freewheel f, in which the ball 29 rolls with play, i.e., without rolling contact, between the parking ball tracks 37 of the disc pair. The contact pressure of the disc pair is therefore generated exclusively by means of the sliding ramps 38 in sliding contact.

[0046] To engage the parking function, the rotating disc 27 is turned in the opposite direction of rotation D to the parking function. P The ball 29 is rotated back to the zero rotation position 0. The ball 29 remaining in the ball-freewheel position P ensures that it comes into rolling contact with the parking ball track 37 at least approximately at the transfer point U and, upon reaching the zero rotation position 0, is again in the ramp recess 39.

[0047] A key aspect of the invention is that the vehicle braking system, according to the Fig. 9 to 11 additionally features a parking lock 41, which consists of a pawl 43 and a cooperating locking gear 45, which is connected to the differential housing 15. When the parking function is engaged, the pawl 43 can be brought into locking engagement with a locking gear 45, whereby the parking lock 41 assists the electrically controlled actuator 21 when the parking function is engaged.

[0048] The pawl 43 and the actuator 21 are motionally coupled to each other via a drive connection 50. The drive connection 50 is constructed as follows: Thus, in the Fig. 9 or Fig. 11 The pawl 43 is rotationally fixed on a parking lock shaft 47, which extends axially parallel to the output shafts 11 and is rotatably mounted in the gearbox housing 19. In addition, a control lever 49 is located at an axial distance from the pawl 43 ( Fig. 9 or Fig. 10) rotationally fixed on the parking lock shaft 47. The control lever 49 is spring-loaded by means of a spring 51 in the direction of a control contour 53, which is formed on the outer circumference of the rotatable disc 27 and with which the control lever 49 is in sliding contact.

[0049] In the Fig. 9 The control contour 53 has a recess or a small-diameter contour section 55, which transitions at a transition flank 57 into a large-diameter contour section 59. In the Fig. 9 The control lever 49 is in sliding contact with the diameter-sized contour section 59, directly adjacent to the transition flank 57. Each of the balls 29 is in its rotationally neutral position 0. During a rotational movement of the rotatable disc 27 into the brake adjustment range S B (according to the Fig. 9 (a counterclockwise rotation) the control lever 49 remains in sliding contact with the large-diameter contour section 59. Accordingly, the pawl 43 also remains disengaged from the locking engagement with the locking gear 45.

[0050] During a rotational movement of the rotatable disc 27 from the one in the Fig. 9 shown rotation zero position 0 in the park position range S P (according to the Fig. 9 a clockwise rotation) the following two cases result: In the first case, the control lever 49 slides from the diameter-sized contour section 59 into the transition flank 57, whereby the pawl 43 comes into tooth-to-tooth contact with the locking gear 45, as shown in the Fig.Figure 11 illustrates this. With further rotation of the rotatable disc 27, the control lever 49 no longer slides along the transition flank 57 to the small-diameter contour section 55, but instead lifts off the control contour 53. Only when the vehicle continues to roll does the pawl 43 engage with the locking gear 45, thus engaging the parking lock 41 and allowing the control lever 49 to come back into contact with the small-diameter contour section 55. In the second case, the pawl 43 immediately engages the locking gear 45 tooth-to-gap immediately after the rotatable disc 27 begins to rotate. The pawl 43 is therefore engaged immediately while the control lever 49 slides along the transition flank 57 to the small-diameter contour section 55. REFERENCE MARK LIST: 3-disc brake 5 Rotor shaft 7 reduction gears 9 axle differential 11 Output shaft 12 Counterholds 13 Axle differential gear 14 Torque support 15 Differential housings 17 outer slat carriers 18 internal slat carriers 19 Gearbox housings 21 Actuator 23 Ball Ramp Unit 25 fixed disc 27 rotating disc 29 balls 30 cage 31 Gearing 34 Ball Ramp 35 Brake ball track 37 Park Ball Track 38 sliding ramps 39 Ramp recess 41 Parking restrictions 43 Locking pawl 45 Locking gear 47th wave of parking restrictions 49 Control levers 50 instinctual connection 51 spring 53 Tax contour 55 diameter smaller contour section 57 Transition flank 59 diameter contour section 0 Rotation zero position U handover point KP Kisspoint P Ball freewheel position s axial spreading path S B Brake adjustment range S P Parking area S P1 , S P2 Sub-areas D B Brake rotation direction D P Parking direction f ball freewheel QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2014 102 831 A1

[0003] EP 3 428 021 A1

[0003]

Claims

[1] Vehicle braking system with at least one multi-disc brake or clutch (3) acting on a vehicle axle, with an electrically controllable actuator (21) by which a braking function for vehicle braking during driving and a parking function when the vehicle is parked can be engaged / disengaged in the multi-disc brake or clutch (3), characterized by , that the vehicle braking system additionally has a parking lock (41) whose locking pawl (43) can be brought into locking engagement with a locking gear (45) when the parking function is engaged. [2] Vehicle according to claim 1, characterized by, that the electrically controlled actuator (21) is in drive connection (50) with the pawl (43), and that the drive connection (50) is designed such that when the parking function is engaged, the actuator (21) not only actuates the multi-plate brake or clutch (3), but also drives the pawl (43) towards its locking position, in which the pawl (43) can be brought into locking engagement with the locking gear (45). [3] Vehicle according to claim 2, characterized by , that the drive connection (50) is designed such that when the parking function is engaged, the actuator (21) not only actuates the multi-plate brake or clutch (3), but also drives the pawl (43) towards its release position, in which the pawl (43) is out of locking engagement with the locking gear (45). [4] Vehicle according to claim 1, 2 or 3, characterized by, that the actuator (21) has a pressure mechanism acting on the multi-disc brake or clutch (3), and that in particular the pressure mechanism consists of a pair of discs comprising a stationary disc (25) and a disc (27) rotatable coaxially thereto, and that in particular for engaging the brake function an electric rotary drive of the actuator (21) rotates the rotatable disc (27) from a zero rotation position (0) in a braking direction (D B ) via a brake rotation angle into a brake adjustment range (S B ) adjusted, and that to engage the parking function, the electric rotary drive of the actuator (21) rotates the disc (27) from the zero position (0) in a direction of rotation relative to the braking direction (D B ) opposite parking rotation direction (D P ) via a parking swivel angle into a parking space (S P ) adjusted. [5] Vehicle according to claim 4, characterized by, that the electrically controlled actuator (21) not only controls the pressure mechanism acting on the multi-plate brake or clutch (3), but also additionally controls the pawl (43) of the parking lock (41) between the locking position, in which the pawl (43) can be brought into locking engagement with the locking gear (45), and the release position, in which the pawl (43) is out of locking engagement with the locking gear (45). [6] Vehicle according to claim 4 or 5, characterized by , that for a pawl actuation the rotatable disc (27) of the disc pair is in drive connection (50) with the pawl (43), so that when the rotatable disc (27) is rotated into the park position range (S P ) the locking pawl (43) can be automatically moved into the locking position, and that when the rotatable disc (27) is rotated out of the park position range (S P ) into the brake adjustment range (S B) the locking pawl (43) can be moved automatically into the release position. [7] Vehicle according to any of the preceding claims, characterized by , that the vehicle axle has an axle differential (9) whose output sides drive to the vehicle wheels via output shafts (11), and that on each output side a multi-plate brake or clutch (3) acts on the respective output shaft (11), and / or that the locking gear (45) of the parking lock (41) is rotationally fixed to an axle differential housing (15), and / or that the parking lock (41) is arranged with axial distance to the respective multi-plate brake or clutch (3). [8] Vehicle according to claim 6 or 7, characterized by, that the drive connection (50) formed between the rotatable disk (27) and the pawl (43) has a parking lock shaft (47) to which a control lever (49) and the pawl (43) axially spaced therefrom are fixedly connected, and that the control lever (49), in particular under spring preload, is in sliding contact with a control contour (53) formed on the rotatable disk (27). [9] Vehicle according to any one of claims 4 to 8, characterized by, that the pressure mechanism acting on the multi-disc brake or clutch (3) has at least one ball-ramp unit (23) with which the multi-disc brake or clutch (3) can be subjected to pressure when the brake function or parking function is engaged and can be pressure-relieved when the brake or parking function is disengaged, and that in particular the ball-ramp unit (23) has a ball (29) which rolls between mutually facing, inclined ball tracks (35, 37) of the disc pair, and that in particular when the brake function is engaged the ball (29) rolls on brake ball tracks (35), with axial spreading of the disc pair over an axial spreading path (s) in order to subject the multi-disc brake / clutch (3) to pressure which varies depending on the size of the brake rotation angle. [10] Vehicle according to claim 9, characterized by, that when the braking function is engaged, a rolling resistance acts between the ball (29) and the brake ball tracks (35) of the disc pair, and that in particular the rolling resistance causes the ball-ramp unit (23) to not be self-locking, i.e., to be open when de-energized, so that in particular the braking effect of the actuator (21) is canceled out in the event of a power failure.

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