WHEEL HUB DRIVE FOR A VEHICLE

Abstract

A wheel hub drive for a vehicle, having: a drive housing; a hub output mounted rotatably relative to the drive housing; a wheel brake for the hub output that has a stationary and a rotating braking partner, the stationary braking partner being connected to the drive housing for conjoint rotation therewith, and the rotating braking partner being connected to the hub output. The two braking partners are frictionally connected in a braking state, A parking brake for fixing the hub output relative to the drive housing. The stationary and rotating brake partners being movable relative to one another when the parking brake is actuated and being frictionally connected to one another in a parked state. The has a ramp mechanism for converting a rotary movement into a linear movement in order to transfer a parking force to the stationary and/or rotating brake partner.

Claims

1. A wheel hub drive for a vehicle, the wheel hub drive comprising: a drive housing; a hub output for coupling to a driven wheel, the hub output being mounted rotatably relative to the drive housing; a wheel brake configured to brake the hub output relative to the drive housing, the wheel brake having a stationary brake partner and a rotating brake partner, the stationary brake partner being connected to the drive housing for conjoint rotation therewith, and the rotating brake partner being connected to the hub output in at least one of a geared manner or for conjoint rotation therewith, the stationary and rotating brake partners being movable relative to one another when the wheel brake device is actuated, and being frictionally connected to one another in a braking state, a parking brake configured to fix the hub output relative to the drive housing, the stationary and rotating brake partners being movable relative to one another when the parking brake is actuated and being frictionally connected to one another in a parked state; and the parking brake has a ramp mechanism, the ramp mechanism being configured to convert a rotary movement into a linear movement in order to transfer a parking force to at least one of the stationary or rotating brake partner.

2. The wheel hub drive according to claim 1, wherein the ramp mechanism has a stationary and a rotatable ramp section, the stationary ramp section being at least one of connected to the drive housing for conjoint rotation therewith or being formed thereby, and the rotatable ramp section being rotatable about a main axis to implement a rotary movement, upon rotation of the rotatable ramp section, and the linear movement being transferable to at least one of the two ramp sections via the ramp mechanism.

3. The wheel hub drive according to claim 2, wherein one of the two ramp sections has a helical toothing on an inner circumference thereof and the other of the two ramp sections has a helical toothing on an outer circumference thereof, the two ramp sections being in engagement with one another to form the ramp mechanism via the helical toothings.

4. The wheel hub drive according to claim 3, wherein the parking brake has a fixing section for fixing the stationary ramp section on the drive housing, the fixing section being mounted on the drive housing, and the stationary ramp section and the fixing section each being in engagement with one another via a straight toothing.

5. The wheel hub drive according to claim 4, wherein the wheel brake has a pressure pad for transmitting a braking force in an axial direction through at least one of the brake partners and, in an opposite axial direction, an end stop for the pressure pad being defined by at least one of the ramp sections, an axial position of the end stop formed by the ramp section being adjustable via the ramp mechanism, so that a wear readjustment for the wheel brake is implemented.

6. The wheel hub drive according to claim 1, wherein the wheel brake has a wheel brake actuator and the parking brake has a parking brake actuator, the parking brake actuator being actuatable independently of the wheel brake actuator.

7. The wheel hub drive according to claim 6, wherein the parking brake actuator is a manual parking brake actuator.

8. The wheel hub drive according to claim 6, wherein the parking brake actuator is a cable, a worm gear or a hydraulic actuator.

9. The wheel hub drive according to claim 1, wherein at least one of (a) the stationary brake partner is configured as at least one axially movable brake pad, or (b) the rotating brake partner is configured as at least one axially movable brake disc.

10. An axle arrangement for a vehicle, comprising two of the wheel hub drives according to claim 1.

11. A wheel hub drive for a vehicle, the wheel hub drive comprising: a drive housing; a hub output for coupling to a driven wheel, the hub output being mounted rotatably relative to the drive housing; a wheel brake configured to brake the hub output relative to the drive housing, the wheel brake having a stationary brake partner and a rotating brake partner, the stationary brake partner being connected to the drive housing, and the rotating brake partner being connected to the hub output in at least one of a geared manner or for conjoint rotation therewith, the stationary and rotating brake partners being movable relative to one another when the wheel brake device is actuated, and being frictionally connected to one another in a braking state, a parking brake configured to fix the hub output relative to the drive housing, the stationary and rotating brake partners being movable relative to one another when the parking brake is actuated and being frictionally connected to one another in a parked state; and the parking brake has a ramp mechanism with a rotatable ramp section configured to move linearly in an axial direction upon a rotational movement thereof to transfer a parking force to at least one of the stationary or rotating brake partner.

12. The wheel hub drive according to claim 11, wherein the ramp mechanism further includes a stationary ramp section that is at least one of connected to the drive housing for conjoint rotation therewith or formed thereby, and the rotatable ramp section engages the stationary ramp section.

13. The wheel hub drive according to claim 12, wherein one of the stationary or rotatable ramp sections has a helical toothing on an inner circumference thereof and the other of the stationary or rotational ramp sections has a helical toothing on an outer circumference thereof, the helical toothings being in engagement with one another.

14. The wheel hub drive according to claim 13, wherein the parking brake has a fixing section for fixing the stationary ramp section on the drive housing, the fixing section being mounted on the drive housing, and the stationary ramp section and the fixing section each being in engagement with one another via a straight toothing.

15. The wheel hub drive according to claim 14, wherein the wheel brake has a pressure pad for transmitting a braking force in an axial direction through at least one of the brake partners and, in an opposite axial direction, an end stop for the pressure pad being defined by at least one of the ramp sections, an axial position of the end stop formed by the ramp section being adjustable via the ramp mechanism to provide wear readjustment for the wheel brake.

16. The wheel hub drive according to claim 1, wherein the wheel brake has a wheel brake actuator and the parking brake has a parking brake actuator, the parking brake actuator being actuatable independently of the wheel brake actuator.

17. The wheel hub drive according to claim 16, wherein the parking brake actuator is a manual parking brake actuator.

18. The wheel hub drive according to claim 16, wherein the parking brake actuator is a cable, a worm gear or a hydraulic actuator.

19. The wheel hub drive according to claim 11, wherein at least one of (a) the stationary brake partner is configured as at least one axially movable brake pad, or (b) the rotating brake partner is configured as at least one axially movable brake disc.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Further features, advantages and effects of the disclosure result from the following description of preferred exemplary embodiments of the disclosure and the attached figures. In the figures:

[0036] FIG. 1 shows a schematic, three-dimensional sectional view of a wheel hub drive as an exemplary embodiment;

[0037] FIGS. 2A and 2B show a three-dimensional detailed view of a stationary and a rotatable ramp section of the wheel hub drive in FIG. 1;

[0038] FIGS. 3A and 3B show a three-dimensional view of a fixing section and a housing cover of the wheel hub drive in FIG. 1.

DETAILED DESCRIPTION

[0039] FIG. 1 shows, in a schematic, three-dimensional sectional view along a main axis H, a wheel hub drive 1 as an exemplary embodiment. The wheel hub drive 1 is designed as a drive motor for an individually driven wheel of a vehicle (not shown).

[0040] The wheel hub drive 1 has a drive housing 2, shown only in sections, which is received in the vehicle for conjoint rotation. Furthermore, a hub output 3 is provided coaxially to the main axis H, the hub output 3 being rotatably supported in the drive housing 2 via a bearing device 4. For example, an electric motor (not shown) is connected on the stator side to the drive housing 2 for conjoint rotation and rotatably connected to the hub output 3 on the rotor side. The electric motor generates a drive torque which is transferred to the driven wheel via the hub output 3.

[0041] A wheel brake device 5 is arranged, in particular integrated, in the drive housing 2. The wheel brake device 5 has an inner carrier 6 and an outer carrier 7. In this exemplary embodiment, the inner carrier 6 is designed as a sheet metal construction which is coupled to the drive housing 3 for conjoint rotation. On the inner carrier 6, two brake pads 8a, b are arranged such that they can be axially displaced relative to one another. A brake disc 9 is arranged on the outer carrier 7, preferably axially displaceable between the two brake pads 8a, b and inserted for conjoint rotation and/or in a form-fitting manner about the main axis H.

[0042] The wheel brake device 5 has a wheel brake actuation device 10, which is designed as a hydraulic wheel brake actuator. The wheel brake actuation device 10 has at least one hydraulic wheel brake actuator 11 as a wheel brake actuation device 10, which acts in the axial direction and applies a braking force F1 to a cylindrical pressure pad 12 in the axial direction. When the wheel brake actuation device 10 is actuated, the pressure pad 12 is displaced in the axial direction in order to compress the two brake pads 8a, b and the brake disc 9 in the axial direction, so that a braking torque is generated.

[0043] In this embodiment, the inner carrier 6 with the two brake pads 8a, b forms a stationary brake partner 13 and the outer carrier 7 with the brake disc 9 forms a rotating brake partner 14.

[0044] Furthermore, a parking brake device 15 is arranged in the drive housing 2, the parking brake device 15 having a ramp mechanism 16 for converting a rotary movement about the main axis H into a linear movement along the main axis H. For this purpose, the ramp mechanism 16 has a stationary ramp section 17 and a rotatable ramp section 18 which can be rotated about the main axis H in order to implement the rotary movement relative to the stationary ramp section 17. The two ramp sections 17, 18 are each designed in an annular manner and are arranged coaxially and/or concentrically to one another with respect to the main axis H. The stationary ramp section 17 is arranged radially in the rotatable ramp section 18 and is in operative connection with the stationary ramp section 17 via the ramp mechanism 15 such that when the ramp section 18 is rotated, it executes the linear movement in the axial direction with respect to the main axis H. A parking force F2 is applied to the brake pads 8a, b and pressed together with the brake disc 9 so that a parking torque is generated.

[0045] The parking brake device 15 has a separate parking actuation device 20 (indicated schematically), the parking actuation device 20 being designed to generate and/or transfer the rotary movement and being connected to the rotatable ramp section 18 in terms of drive and/or transmission technology. For example, the parking actuator 20 can be formed as a cable, a worm gear or a hydraulic actuation actuator, e.g., a hydraulic cylinder. The rotatable ramp section 18 is supported in the axial direction with respect to the main axis H and via the pressure pad 12 on the brake pad 8b. To fix the vehicle wheel, the rotatable ramp section 18 is rotated with the aid of the parking actuation device 20, the rotatable ramp section 18 at the same time being moved axially by the ramp mechanism 16 and thus the pressure pad 12 being able to be actuated by the parking actuation device 15 independently of the wheel brake actuation device 10. With this structure, the wheel brake actuation device 10 and the parking actuation device 15 can be actuated independently of one another. In normal operation, the wheel brake actuation device 10 is used to brake the driven wheel 2 when the vehicle is traveling. In contrast, the parking actuator 15 is used to fix the driven wheel 2 when parking the vehicle.

[0046] The stationary ramp section 17 is connected to the drive housing 2 via an annular fixing section 19. The drive housing 2 has a housing cover 21, which closes the drive housing 2 in the axial direction with respect to the main axis H. The fixing section 19 is arranged coaxially to the main axis H and is firmly connected to the housing cover 21. For this purpose, the housing cover 21 has a receiving section 22, which in the exemplary embodiment shown is designed as a cylindrical extension. The fixing section 19 is positively received on the receiving section 22 and is connected to the housing cover 21, for example via a screw connection. In addition, the rotatable ramp section 17 has a radially inwardly directed collar section 23, the collar section 23 being held in a form-fitting manner in the axial direction with respect to the main axis H between the fixing section 19 and the housing cover 21. An axial securing of the stationary ramp section 17 is thus also implemented.

[0047] Furthermore, the parking brake device 15 can serve to adjust the wear of the wheel brake device 5. For this purpose, the rotatable ramp section 18 can be precisely positioned axially by the parking actuation device 20 and the ramp mechanism 16, the ramp section 18 simultaneously serving as a support surface for the pressure pad 12. An axial end stop for the pressure pad 12 is thus formed, the pressure pad 12 resting against the end stop when the wheel brake device 5 and the parking brake device 15 are in an open state. This end stop formed by the ramp section 18 or the exact axial position of the ramp section 18 can be stored in the parking brake device 15 for setting the wear readjustment if the parking actuation device 20 is self-locking. For example, a restoring element, such as a plate spring or a compression spring assembly, is provided to generate a restoring force F3 in order to push the pressure pad 12 back in the direction of the end stop formed by the stationary ramp section 23. This ensures that the wheel brake device 5 opens again completely after actuation.

[0048] FIG. 2A shows the stationary ramp section 17 in a perspective detailed view. FIG. 2B shows the rotatable ramp section 18 in a perspective detailed view. The two ramp sections 17, 18 are each designed as a toothed ring. To form the ramp mechanism 16, as shown in FIG. 1, the stationary ramp section 17 on its outer circumference and the rotatable ramp section 18 on its inner circumference each have a helical toothing 24a, b, the two ramp sections 17, 18 each having the helical toothing 24a, b being engaged with each other. The helical gears 24a, b are each formed by grooves and bars which run obliquely to the main axis H and which extend circumferentially around the main axis H in alternating sequence. In the event of a relative rotation of the two ramp sections 17, 18, the two ramp sections 17, 18 slide off one another via the helical toothing 24a, b so that the two ramp sections 17, 18 are axially displaced relative to one another. As shown in FIG. 1, this linear movement is used to press the brake pads 8a, b together with the brake disc 9 and to fix the wheel.

[0049] It thus becomes a parking brake device 15 which can be actuated with a low expenditure of force, wherein the parking force F2 can be transmitted to the wheel brake device 5 in a reinforced manner by the ramp mechanism 16. As a result, a robust parking brake device 15 can be implemented in a simple manner, which can also be produced simply and inexpensively.

[0050] The stationary ramp section 17 has a straight toothing 25a on its inner circumference, which serves for the connection to the fixing section 19 with conjoint rotation. The straight toothing 25a is formed by several grooves and bars running parallel to the main axis H and in an alternating arrangement. The straight toothing 25a directly adjoins the collar 23 directed radially inward.

[0051] FIG. 3A shows the fixing section 19 in a three-dimensional representation and FIG. 3B shows the housing cover 21. The fixing section 19 is designed as a further toothed ring. The fixing section 19 has on its outer circumference a straight toothing 25b corresponding to the straight toothing 25a, the straight toothing 25a of the stationary ramp section 17 and the straight toothing 25b of the fixing section 19 jointly forming a plug-in toothing. For assembly, the stationary ramp section 17 can be plugged with its straight toothing 25a onto the straight toothing 25b of the fixing section 19 in the axial direction with respect to the main axis H. The stationary ramp section 17 can be pushed onto the fixing section 19 until the ramp section 17 rests with its collar 23 on an end face of the fixing section 19. The fixing section 19 can then be mounted on the housing cover 21 together with the preassembled ramp section 17. It can optionally be provided that the rotatable ramp section 18 is also already preassembled on the stationary ramp section 17. In an assembled state, the stationary ramp section 17 is therefore fixed in the axial direction with respect to the main axis H by the collar section 23 and in the circumferential direction by the straight toothing 25a, b on the drive housing 2, in particular the housing cover 21.

[0052] The fixing section 19 has multiple fastening tabs 26 directed radially inward, each of the fastening tabs 26 serving to receive a fastening means, for example a screw. The receiving section 22 forms a contour partner to the fixing section 19, the receiving section 22 having a negative contour 27 for this purpose. During assembly, the fixing section 19 is inserted into the negative contour 27 in a form-fitting manner on the receiving section 22. The fixing section 19 is then fixed to the housing cover 21 via the fastening means, so that the fixing section 19, in particular together with the stationary and optionally the rotatable ramp section 17, 18, is held captive.

LIST OF REFERENCE SYMBOLS

[0053] 1 Wheel hub drive [0054] 2 Drive housing [0055] 3 Hub output [0056] 4 Bearing device [0057] 5 Wheel brake device [0058] 6 Inner carrier [0059] 7 Outer carrier [0060] 8a,b Brake pads [0061] 9 Brake disc [0062] 10 Wheel brake actuation device [0063] 11 Hydraulic wheel brake actuator [0064] 12 Pressure pad [0065] 13 Rotating brake partner [0066] 14 Rotating brake partner [0067] 15 Parking brake device [0068] 16 Ramp mechanism [0069] 17 Stationary ramp section [0070] 18 Rotatable ramp section [0071] 19 Fixation section [0072] 20 Parking actuation device [0073] 21 Cover housing [0074] 22 Cylinder section [0075] 23 Collar [0076] 24a, b Helical toothing [0077] 25a, b Straight toothing [0078] 26 Fastening straps [0079] 27 Negative contour [0080] F1 Braking force [0081] F2 Parking force [0082] F3 Restoring force [0083] H Main axis