Vehicle braking system

Abstract

The invention relates to a vehicle braking system comprising at least one multi-disc brake or clutch (3) acting on a vehicle axle of a vehicle and having an electrically controllable actuator (21), by means of which a brake function for a vehicle braking process during a driving operation 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), wherein the locking pawl (43) thereof can be brought into locking engagement with a locking gearwheel (45) when the parking function is engaged.

Description

[0001] Vehicle braking system

[0002] DESCRIPTION:

[0003] The invention relates to a vehicle braking system according to the preamble of claim 1.

[0004] 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 during ferry operations 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 via 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 additional installation space and involves considerable design effort.

[0005] 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.

[0006] The object of the invention is to provide a vehicle braking system that, compared to the prior art, can be implemented with reduced installation space and reduced design effort. This object is achieved by the features of claim 1. Preferred embodiments of the invention are disclosed in the dependent claims.

[0007] 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 operation 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 braking concept that is simplified in terms of cost, installation space, and component weight compared to the prior art. 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.

[0008] 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.

[0009] 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.

[0010] 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 axial spreading of the disc pair over a specific axial spreading 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.

[0011] 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.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] 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 on the parking ball tracks of the disc pair. This occurs with axial spreading of the disc pair over an 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.

[0016] 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.

[0017] 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.

[0018] The parking ball tracks and the braking ball tracks can transition into each other in the circumferential direction of the disc at a ramp recess. This defines the zero rotation position. The parking ball tracks can be designed to be mirror-symmetrical to 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 clearance of the multi-disc brake / clutch is first eliminated. Subsequently, a kiss point is reached at which the multi-disc brake / Z-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 in the parking range.

[0019] 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 ball-freewheel position. In this ball-freewheel position, the ball can roll freely between the parking ball tracks of the disc pair, without any rolling contact.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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 arranged at an axial distance from the respective multi-plate brake or clutch. The frictional 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:

[0027] Figs. 1 to 11 show different views, which describe the structure and function of the vehicle braking system according to the invention.

[0028] 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, the vehicle axle has multi-disc brakes 3, which enable vehicle braking. The vehicle axle also has a parking lock 41 (not shown in Figure 1 or 2), the construction and function of which will be described later with reference to Figures 9 to 11.

[0029] The electric motor EM is connected via its rotor shaft 5 and a reduction gear 7 to the input side of an axle differential 9. The output sides of the differential are connected to the vehicle wheels via output shafts 11. In Figure 1, the electric motor EM is mounted 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 mounted in the vehicle axle are aligned parallel to each other in the transverse direction y of the vehicle. Viewed in the transverse direction y, the vehicle axle has one multi-disc brake 3 on each side of the vehicle. These brakes can be controlled by an electronic control unit (not shown) to achieve uniform or uneven braking at both vehicle wheels.

[0030] The reduction gear 7 is in close connection with an input-side axle differential gear 13. The axle differential gear 13 is fixedly connected to a rotating differential housing 15. As shown in Figure 1, with the multi-disc brakes 3 open, the axle differential 9 drives in the transverse direction y of the vehicle in a 50 / 50 distribution to both output shafts 11 leading to the vehicle wheels.

[0031] In Figure 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 using electrical signals.

[0032] The actuator 21 is shown in Figures 2 to 3c. It consists of a spindle drive (not shown) with an electric motor, which is directionally connected to a toothed section 31 of a rotatable disc 27. The non-rotating disc 25 can be supported circumferentially by an indicated torque support 14. The non-rotating disc 25 is also 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 Figures 3a to 3b. Each ball-ramp unit 23 has a ball 29 that rolls between the two discs 25 and 27. The slat assembly located between the outer slat carrier 39 and the inner slat carrier can be subjected to clamping pressure by means of the actuator 21.Depending on the control signal of the actuator 21, a braking function for vehicle braking during ferry operation, 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 using 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.

[0033] 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 guided in a cage 30, as shown in Figure 3b. In Figures 4a and 4b, one of the ball-ramp units 23 is shown in its developed form. Figure 4a shows two corresponding sliding ramps 38 of the disk pair, while Figure 4b shows two corresponding ball ramps 34 of the disk 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 one another at a ramp recess 39. In Figure 4a, the ball 29 is located in the ramp recess 39. The ramp recess 39 defines a rotation zero position 0, in which the disc pair exerts no contact pressure on the lamella pack.The ball ramps 34 of the two discs 25, 27 are point-symmetrical to each other with respect to the ball 29. Furthermore, the parking ball track 37 and the braking ball track 35 of each ball ramp 34 are symmetrical to each other with equal inclination angles with respect to an axis of symmetry passing through the ramp recess 39.

[0034] A key feature of the invention is that, depending on the direction of rotation DB, DP of the rotatable disc 27, either a braking function for vehicle braking during ferry operation or, alternatively, a parking function when the vehicle is parked can be engaged or disengaged. 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.

[0035] Figures 4a and 4b show the pair of disks in their zero-rotation position 0. In the zero-rotation position 0, the two sliding ramps 38 are out of contact (unlike in Figure 4a). According to Figure 4b, the ball 29 is located in the ramp recesses 39 of the ball ramps 34 of the two disks 25, 27.

[0036] The engagement of the brake function is described below with reference to Figures 5a to 6b. Starting from the zero position 0 shown in Figures 4a and 4b, the rotatable disc 27 is moved to the left in a braking direction DB via a braking rotation angle into a braking adjustment range SB. This causes the ball 29 to roll on the two brake ball tracks 35 of the disc pair, with axial spreading of the disc pair via an axial spreading path s. In this way, the disc pack of the multi-disc brake 3 is subjected to contact pressure. The contact pressure varies depending on the size of the braking rotation angle. Immediately after leaving the zero position 0, the rotatable disc 27 is moved by an axial spreading path s, which eliminates any play in the disc pack.Further rotation of the rotatable disc 27 within the brake adjustment range SB results in a kiss point KP (Figure 5b) at which the multi-disc brake 3 transmits a measurable, predefined torque. At the kiss point KP, the rotatable disc 27 (starting from the zero rotation position 0) is rotated by a first axial displacement Asi. In Figures 6a and 6b, the rotatable disc 27 is adjusted to an end position in which it is rotated by a second axial displacement AS2.

[0037] 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 remain 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.

[0038] To activate the brake function, the rotatable disc 27 (starting from its end position (Figures 6a and 6b) is moved back to the zero position 0 (Figures 4a and 4b) in the opposite direction to the brake rotation DB.

[0039] During the adjustment movement in the brake adjustment range SB, the corresponding, inclined sliding ramps 38 remain out of contact with each other, so that smooth rotary adjustment of the rotatable disc 27 is ensured.

[0040] The engagement of the parking function is described below with reference to Figures 7a to 8b. Starting from the zero position 0 shown in Figures 4a and 4b, the rotatable disc 27 is rotated to the right in a parking direction Dp, opposite to the brake direction DB, via a parking angle into a parking position SP.

[0041] According to Figure 7b, the parking area SP is divided into a first sub-area SPI and a second sub-area SP2. In the first sub-area SPI, the ball 29 rolls between the facing parking ball tracks 37 of the disc pair, while the corresponding sliding ramps 38 are still out of sliding contact. In contrast, in the second sub-area SP2, the sliding ramps 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 moved from the zero rotation position 0 in the parking rotation direction Dp by a parking rotation angle into the first sub-area SPI until a transfer point U is reached, as indicated in Figures 7a and 7b. According to Figures 7a and 7b, the disc pair generates a third axial spreading path Ass. at the transfer point U.During the adjustment movement in the first section SPI, the ball 29 rolls on 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 is rotated into the second section SP2 with a further increasing parking rotation angle until the parking function is engaged.

[0042] To ensure reliable engagement of the parking function, the transfer point U located in the parking position SP is positioned between the rotational zero position 0 and the kiss point KP. When engaging the parking function, 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.

[0043] In Figures 8a and 8b, the rotatable disc 27 is rotated to its parked end position, in which the parking function is fully engaged. With the parking function engaged, the ball 29 is in a predefined ball-freewheel position P (Figure 8b). The ball-freewheel position P is defined in Figure 8b by means of ball track exits 41 of the parking ball tracks 37. With the parking function engaged, the ball track exits 41 are spaced apart 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.

[0044] To engage the parking function, the rotatable disc 27 is turned back in the opposite direction of rotation Dp to the zero-rotation position 0. The ball 29 remaining in the ball-free-running position P ensures that the ball 29 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.

[0045] A key aspect of the invention is that the vehicle braking system according to Figures 9 to 11 additionally includes 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.

[0046] The pawl 43 and the actuator 21 are movably coupled to each other via a drive connection 50. The drive connection 50 is constructed as follows: In Figures 9 or 11, the pawl 43 is fixedly mounted on a parking lock shaft 47, which extends parallel to the output shafts 11 and is rotatably mounted in the gearbox housing 19. Furthermore, a control lever 49 (Figures 9 or 10) is fixedly mounted on the parking lock shaft 47 at an axial distance from the pawl 43. The control lever 49 is spring-loaded by a spring 51 in the direction of a control contour 53, which is formed on the outer circumference of the rotatable disk 27 and with which the control lever 49 is in sliding contact.

[0047] In Figure 9, the control contour 53 has a recess or a small-diameter contour section 55, which transitions at a transition flank 57 into a larger-diameter contour section 59. In Figure 9, the control lever 49 is in sliding contact with the larger-diameter contour section 59, directly adjacent to the transition flank 57. Each of the balls 29 is in its zero-rotation position 0. When the rotatable disc 27 rotates into the brake adjustment range SB (a counterclockwise rotation according to Figure 9), the control lever 49 remains in sliding contact with the larger-diameter contour section 59. Accordingly, the pawl 43 also remains disengaged from the locking gear 45.When the rotatable disc 27 rotates from the zero position 0 shown in Figure 9 to the park position SP (a clockwise rotation according to Figure 9), the following two cases occur: In the first case, the control lever 49 slides from the diameter-sized contour section 59 into the transition flank 57, causing the pawl 43 to engage tooth-on-to-toe.

[0048] The tooth comes into contact with the locking gear 45, as shown in Figure 11. Therefore, with further rotation of the rotatable disc 27, the control lever 49 no longer slides along the transition flank 57 to the smaller diameter contour section 55, but instead lifts off the control contour 53 at 49. Only when the vehicle continues to roll does the pawl 43 engage the locking gear 45, thus engaging the parking lock.

[0049] 41 is engaged and the control lever 49 comes back into contact with the small-diameter contour section 55. In the second case, the pawl 43 immediately comes into tooth-to-gap contact with the locking gear 45 after the start of the disk rotation of the rotatable disk 27. 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.

[0050] REFERENCE MARK LIST:

[0051] 3-disc brake

[0052] 5 Rotor shaft

[0053] 7 reduction gears

[0054] 9 axle differential

[0055] 11 Output shaft

[0056] 12 Counterholds

[0057] 13 Axle differential gear

[0058] 14 Torque support

[0059] 15 Differential housings

[0060] 17 outer slat carriers

[0061] 18 internal slat carriers

[0062] 19 Gearbox housings

[0063] 21 Actuator

[0064] 23 Ball Ramp Unit

[0065] 25 fixed disc

[0066] 27 rotating disc

[0067] 29 balls

[0068] 30 cage

[0069] 31 Gearing

[0070] 34 Ball Ramp

[0071] 35 Brake ball track

[0072] 37 Park Ball Track

[0073] 38 sliding ramps

[0074] 39 Ramp pen recess

[0075] 41 Parking restrictions

[0076] 43 Locking pawl

[0077] 45 Locking gear

[0078] 47th wave of parking restrictions

[0079] 49 Control levers

[0080] 50 instinctual connection

[0081] 51 spring

[0082] 53 Control contour 55 Diameter smaller contour section

[0083] 57 Transition flank

[0084] 59 diameter contour section 0 rotation zero position U transfer point

[0085] KP Kisspoint

[0086] P Ball freewheel position s Axial spreading path

[0087] SB Brake Positioning Area SP Parking Positioning Area

[0088] SRI, SP2 sub-areas

[0089] DB Brake Direction of Rotation

[0090] DP Park direction of rotation f ball freewheel

Claims

PATENT CLAIMS:

1. Vehicle braking system with at least one multi-disc brake or clutch (3) acting on a vehicle axle of a vehicle, with an electrically controllable actuator (21) by which a braking function for vehicle braking during ferry operation and a parking function when the vehicle is parked can be engaged / disengaged in the multi-disc brake or clutch (3), characterized in that 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.

2. Vehicle according to claim 1, characterized in that the electrically controllable 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 additionally drives the pawl (43) in the direction of 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 in 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 additionally drives the pawl (43) in the direction of 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 in that the actuator (21) has a pressure mechanism acting on the multi-plate brake or clutch (3), and in particular that the The pressure mechanism consists of a pair of discs comprising a stationary disc (25) and a coaxially rotatable disc (27), and in particular, for engaging the brake function, an electric rotary drive of the actuator (21) adjusts the rotatable disc (27) from a zero rotation position (0) in a brake rotation direction (DB) via a brake rotation angle into a brake setting range (SB), and for engaging the parking function, the electric rotary drive of the actuator (21) adjusts the rotatable disc (27) from the zero rotation position (0) in a parking rotation direction (Dp) opposite to the brake rotation direction (DB) via a parking rotation angle into a parking setting range (SP).

5. Vehicle according to claim 4, characterized in that the electrically controllable 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 in 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 (SP) the pawl (43) can be automatically brought into the locked position, and that when the rotatable disc (27) is rotated from the park position (SP) into the brake position (SB) the pawl (43) can be automatically brought into the release position.

7. Vehicle according to one of the preceding claims, characterized in 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 in that the drive connection (50) formed between the rotatable disc (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 disc (27).

9. Vehicle according to one of claims 4 to 8, characterized in 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 in particular that the ball-ramp unit (23) has a ball (29) which rolls between mutually facing, inclined ball tracks (35, 37) of the disc pair, and in particular that when the brake function is engaged the ball (29) rolls on brake ball tracks (35), whereby the disc pair is axially spread 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 in 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 in particular that 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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