ELECTROMECHANICAL BRAKE

Abstract

An electromechanical brake. The electromechanical brake includes an electromechanical actuating device which includes an electric motor, which interacts with a transmission, and a ramp mechanism, the ramp mechanism converting a rotational drive movement of the electric motor into a translational movement for applying a braking force. The electric motor and the transmission are arranged coaxially with each other and are at least partially surrounded by the ramp mechanism.

Claims

1-11. (canceled)

12. An electromechanical brake, comprising: an electromechanical actuating device which includes an electric motor, which interacts with a transmission, and a ramp mechanism, the ramp mechanism configured to convert a rotational drive movement of the electric motor into a translational movement for applying a braking force; wherein the electric motor and the transmission are arranged coaxially with each other and are at least partially surrounded by the ramp mechanism.

13. The electromechanical brake according to claim 12, wherein the ramp mechanism includes a cup-shaped drive element connected to the transmission and a cam ring.

14. The electromechanical brake according to claim 13 wherein a bearing arrangement with at least one radial bearing interacting with the cam ring is arranged between the cam ring and a floor of the housing, via which a braking force can be supported on the floor of the housing.

15. The electromechanical brake according to claim 13, wherein the cam ring is arranged in a brake piston, which together form a mechanism to regulate wear.

16. The electromechanical brake according to claim 15, wherein the cam ring has stops at ends of a curve formed on the cam ring, wherein, when the stops are reached, the cam ring can be rotated in the brake piston for wear regulation.

17. The electromechanical brake according to claim 13, wherein the cam ring has a depression after a rise in a curve formed on the cam ring so that the brake can be locked in a parked position.

18. The electromechanical brake according to claim 13, wherein the cam ring includes internal gear toothing which is engaged with a gear configured with a freewheel, such that the cam ring can be rotated only in one direction for wear adjustment.

19. The electromechanical brake according to claim 18, wherein the gear is arranged eccentrically to a cylindrical component attached to the brake piston, which, by a rotation, causes the gear to disengage such that the cam ring can be reset.

20. The electromechanical brake according to claim 12, wherein compression springs are arranged between brake pads of the brake, via which the brake pads can be separated from a brake disc.

21. The electromechanical brake according to claim 12, wherein the transmission is at least a single-stage planetary transmission.

22. A vehicle brake system, comprising: at least one electromechanical brake including: an electromechanical actuating device which includes an electric motor, which interacts with a transmission, and a ramp mechanism, the ramp mechanism configured to convert a rotational drive movement of the electric motor into a translational movement for applying a braking force; wherein the electric motor and the transmission are arranged coaxially with each other and are at least partially surrounded by the ramp mechanism.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 shows a sectional view of an electromechanical brake according to a first embodiment example of the present invention.

[0023] FIG. 2 shows a perspective view of an embodiment example of a cam ring, according to the present invention.

[0024] FIG. 3 shows a sectional view through the drive pulley, according to an example embodiment of the present invention.

[0025] FIG. 4 shows a view of a curve of the cam ring, according to an example embodiment of the present invention.

[0026] FIG. 5 shows a sectional view of an electromechanical brake according to a second embodiment example of the present invention.

[0027] FIG. 6 shows sectional view of an electromechanical brake according to a third embodiment example of the present invention.

[0028] FIG. 7 shows an enlarged view of an anti-rotation feature.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0029] FIG. 1 shows a sectional view of an electromechanical brake 4 according to a first embodiment example of the present invention. The electromechanical brake 4 comprises an actuating device 8, via which a braking force FB can be applied to brake pads 12 of the electromechanical brake. The actuating device 8 comprises an electric motor 16, which is configured as an electronically commutated motor. The electric motor 16 drives a drive axle 20 connected to a transmission 24. In the embodiment example shown, the transmission 24 is configured as a two-stage planetary gear transmission, which is arranged coaxially with the electric motor 16. In order to be able to detect a position of a rotor of the electric motor 16, a rotor position sensor 28 is arranged on a side of the drive axle 20 facing away from the transmission 24.

[0030] On the output side, the planetary gear transmission 24 is connected to a cup-shaped drive element 32. The cup-shaped drive element 24 is configured to partially surround the planetary gear transmission 24 and the electric motor 16 on the outer side. Additionally, the cup-shaped drive element 32 forms a ring disc 36 that is arranged coaxially with the drive axle 20. The ring disc 36 together with a cam ring 40 forms a ramp mechanism 44, via which a rotational drive movement of the ring disc 36 can be converted into a translational movement of a brake piston 48 connected to the cam ring 40.

[0031] FIG. 2 shows a perspective view of an embodiment example of the cam ring 40. In this figure, it can be seen that the cam ring 40 has three identical curves 52, which are arranged along a front side 56 of the cam ring 40. The curves 52 have different axial elevations of the cam ring 40. Three cam radial bearings 60 shown in FIG. 1 and FIG. 3 interact with the cam ring 40 and roll along the curves 52 of the cam ring 40. As shown in FIG. 3, the cam radial bearings 60 are constrained to the ring disc 36 by means of ring disc axles 64. The ring disc 36 has three notches 68, in each of which a radially extending ring disc axle 64 is arranged.

[0032] In addition to the cam radial bearings 60, two support radial bearings 72 are respectively arranged on the ring disc axles 64, which are provided on both sides of the cam radial bearing 60.

[0033] Compared to the cam radial bearing 60, the support radial bearings 72 have a larger external diameter D.sub.S, as shown in FIG. 1. As a result, the support radial bearings 72 abut a support ring disc 76 located on a floor of the housing 80 of the electromechanical brake 4. Since an external diameter D.sub.K of the cam radial bearing 60 is less than the external diameter D.sub.S of the support radial bearing 72, this radial bearing 60 does not abut the support ring disc 76. Due to a narrow radial thickness of the cam ring 40, the support radial bearings 76 do not abut the cam ring 40, but instead run freely on both sides of the cam ring 40.

[0034] The cam ring 40 is received in the brake piston 48, which acts on the brake pad 12. The brake piston 48 and cam ring 40 each form a thread 88, via which the cam ring 40 is screwed into the brake piston 48. Wear regulation of the brake pads 12 is possible via this thread 88. Accordingly, when the cam ring 40 is screwed in the direction out of the brake piston 48, wear on the brake pads 12 may be adjusted. The thread 88 is configured to prevent rotation generated by a normal operating movement. Compression springs 92 are arranged between the brake pads 12, by means of which the brake pads 12 are pushed apart after a braking operation. This avoids grinding of the brake pads 12 on a brake disc (not shown). The brake pad wear can thus be reduced accordingly.

[0035] FIG. 4 shows a view of a curve 52 of the cam ring 40. The curve radial bearing 60 runs on this curve 52. After a first rise 96, a depression 100 is formed, into which the cam radial bearing 60 can stably lock into place. A parking brake function is formed via this depression 100. Additionally, curve 52 has two stops 104 that the curve radial bearing 60 may run into. By means of further rotation beyond these stops 104, it is possible to generate rotation of the cam ring 40 in the brake piston 48. This allows the wear to be regulated in a simple manner. Likewise, after changing a brake pad 12, the wear can be completely reversed.

[0036] FIG. 5 shows a sectional view of an electromechanical brake 4 according to a second embodiment example of the invention. This embodiment example differs from the electromechanical brake 4 of FIG. 1 in that the brake piston 48 is designed as a stepped brake piston 48. Accordingly, another step 108 is provided in the area of the electric motor 16 and the transmission 24. The electromechanical brake 4 can thus be configured even more compactly. By means of the stepped shape of the brake piston 48, it is possible to place a frontmost portion of the brake piston 48 in the area of a rim.

[0037] The embodiment example of FIG. 5 additionally differs from the first embodiment example in that no support radial bearings 72 are provided. In this embodiment example, only the cam radial bearing 60 is provided. Instead of the support radial bearing 72, a support axial bearing 112 is located between the curve radial bearing 60 and the floor of the housing 80. By means of the support axial bearing 112, it is possible for the forces to be transferable to the floor of the housing 80.

[0038] FIG. 6 shows a sectional view of an electromechanical brake 4 according to a third embodiment example of the invention. This embodiment example differs from the embodiment example of FIG. 1 in that an anti-rotation feature 116 is provided for the cam ring 40. By means of this anti-rotation feature 116, only a rotation of the cam ring 40 in one direction is permitted, so that unintended rotation of the cam ring 40 during normal use is prevented. For the anti-rotation feature 116, the cam ring 40 comprises internal gear toothing 124 on an inner peripheral surface 120.

[0039] The anti-rotation feature 116 includes a cylindrical pin 128. The pin 128 is divided into two regions 128a, 128b, wherein a first region 128a is located on the brake piston 48. A second region 128b adjoins the first region 128a and extends into the area of the internal gear toothing 124 of the cam ring 40. Attached to the second region 128b of the pin 128 is a gear 132 that engages with the internal gear toothing 124. A freewheel 136 is provided between pin 128 and gear 132 so that gear 132 can only rotate in one direction.

[0040] FIG. 7 shows an enlarged view of the pin 128 and gear 132. In this figure, it can be seen that the second region 128b, and thus also the axis of rotation 138 of the gear 132, is provided eccentrically to an axis of rotation 139 of the first region 128a. Thus, rotation of the first region 128a disengages the gear 132 from the internal gear toothing 124. As a result, when brake pad 12 is changed, cam ring 40 may be screwed back into brake piston 48 to be able to reset the wear to zero again.

[0041] To avoid unintended rotation of the first region 128a during use, a slot 140 is formed at an axial end of the first region 128a. This slot 140 interacts with a bar 144 of the brake pad such that the bar 144 engages in the slot 140 and rotation is prevented. In addition, this slot-and-bar connection allows for poka-yoke safe installation. If pin 128 is rotated, it is not possible to install the brake pad 12, so that installation of brake pad 12 is only possible with a correctly aligned pin 128.