ACTUATING DRIVE COMPRISING A TORQUE-LIMITING DEVICE

Abstract

The invention relates to a control drive, in particular a spindle drive for adjusting a swivellable vehicle flap, comprising a housing (2), a spindle rod (3) that is rotatably mounted in the housing (2), a first coupling element (5) for driving a rotational movement of the spindle rod (3), and a torque-limiting device (6) arranged between the first coupling element (5) and the spindle rod (3) for limiting the torque transmitted from the first coupling element (5) to the spindle rod (3), comprising an adapter sleeve (8) arranged at a first end (3a) of the spindle rod (3) in a rotationally fixed manner, and a first tolerance element (13) arranged between the spindle rod (3) and the first coupling element (5). According to the invention, a control drive is provided, which is designed such that it is compact and can be economically produced, in such a way that the first tolerance element (13) is rotationally fixed to one of the first coupling element (5) and the adapter sleeve (8).

Claims

1 to 14. (canceled)

15. An actuating spindle drive for adjusting a pivotable vehicle flap, the actuating spindle drive comprising a housing; a spindle rod rotatably mounted in the housing; a first coupling element for driving a rotational movement of the spindle rod; and a torque-limiting device arranged between the first coupling element and the spindle rod for limiting the torque transmitted from the first coupling element to the spindle rod, the torque-limiting device comprising: an adapter sleeve arranged at a first end of the spindle rod in a rotationally fixed manner, and a first tolerance element arranged between the spindle rod and the first coupling element, the first tolerance element being rotationally fixed to one of the first coupling element and the adapter sleeve.

16. The actuating spindle drive according to claim 15, wherein the one of the first coupling element and the adapter sleeve has at least one first retaining element.

17. The actuating drive according to claim 16, wherein the first retaining element is a projection having a first lateral support surface and a second lateral support surface.

18. The actuating drive according to claim 16, wherein the first retaining element is formed integrally with the one of the first coupling element and the adapter sleeve.

19. The actuating drive according to claim 17, wherein the first tolerance element is supported at least on the first lateral support surface of the first retaining element.

20. The actuating drive according to claim 19, wherein the first tolerance element is supported on the first lateral support surface and on the second lateral support surface.

21. The actuating drive according to claim 16, wherein the first tolerance element is a partially cylindrical shell element.

22. The actuating drive according to claim 17, wherein the torque-limiting device comprises a second tolerance element.

23. The actuating drive according to claim 22, wherein the second tolerance element is supported at least on the second lateral support surface of the first retaining element.

24. The actuating drive according to claim 17, wherein the one of the first coupling element and the adapter sleeve comprises at least one second retaining element, wherein the second retaining element is a projection having a first lateral support surface and a second lateral support surface.

25. The actuating drive according to claim 24, wherein the first tolerance element is supported on the first lateral support surface of the first retaining element and on the first lateral supporting surface of the second retaining element.

26. The actuating drive according to claim 16, wherein the first coupling element has a hollow cylindrical receptacle that faces the spindle rod and has a base and a side wall.

27. The actuating drive according to claim 26, wherein the first tolerance element and the adapter sleeve are at least partially accommodated in the hollow cylindrical receptacle.

28. The actuating drive according to claim 27, wherein the first retaining element is arranged on an inner side of the side wall of the hollow cylindrical receptacle.

29. The actuating drive according to claim 28, wherein the first tolerance element abuts flat against the inner side wall of the hollow cylindrical receptacle.

30. The actuating drive according to claim 15, wherein a brake assembly is arranged in the housing, wherein the brake assembly comprises a housing.

31. The actuating drive according to claim 30, wherein the brake housing is arranged concentrically around a first end of the spindle rod.

32. The actuating drive according to claim 30, wherein the first coupling element at least partially penetrates the brake housing of the brake assembly.

33. The actuating drive according to claim 30, wherein the brake assembly comprises first brake element, a second brake element and a pretensioning means for axially pretensioning the first brake element to the second brake element, wherein the pretensioning means and one of the adapter sleeve and the first tolerance element overlap axially at least in sections.

34. The actuating drive according to claim 30, wherein the torque-limiting device is partially inserted into the brake assembly through an opening provided in the brake housing.

Description

[0037] The invention is explained in more detail below with reference to the accompanying drawings using a preferred exemplary embodiment.

[0038] FIG. 1 shows a preferred exemplary embodiment of an actuating drive in a lateral cross-sectional view,

[0039] FIG. 2 shows a frontal cross-sectional view of the torque-limiting device from FIG. 1 of the actuating drive.

[0040] FIG. 3 shows the torque-limiting device from FIG. 1 in an exploded view.

[0041] FIG. 1 shows a preferred exemplary embodiment of an actuating drive 1 in a lateral cross-sectional view. The actuating drive 1, shown in sections, comprises a housing 2, wherein the housing 2 is hollow cylindrical and concentrically surrounds a spindle rod 3. The spindle rod 3 is rotatably mounted in the housing 2 via a ball bearing 4.

[0042] In a section (not shown here), the spindle rod 3 has a drive thread that meshes with a spindle nut (not shown here) with a corresponding internal thread, so that when the spindle rod 3 rotates, the spindle nut is displaceable together with a housing part of the housing 2 in the direction of a longitudinal axis X of the spindle rod 3.

[0043] To drive the rotational movement of the spindle rod 3, a coupling element 5 is coupled to a first end 3a of the spindle rod 3, wherein a torque-limiting device 6 is arranged between the coupling element 5 and the spindle rod 3, said torque-limiting device 6 limiting a torque transmitted from the first coupling element 5 to the spindle rod 3. Advantageously, the torque-limiting device 6 can be used to decouple excessive external forces, which occur, for example, by an action on the vehicle flap, for example a collision with an obstacle, from the transmission section or the electric motor. This advantageously makes it possible to avoid damage to the electric motor or the transmission.

[0044] The coupling element 5 is designed as a transmission adapter, wherein the coupling element 5 comprises a first end 5a facing away from the spindle rod 3, which end 5a is designed in the form of a pin and can be connected to a transmission (not shown here) or an output shaft of a motor. Furthermore, the coupling element 5 comprises a second end 5b facing the spindle rod 3, which second end is designed to be pot-shaped and forms a hollow cylindrical receptacle 7. The hollow cylindrical receptacle 7 has an annular base 7a and a hollow cylindrical side wall 7b. The torque-limiting device 6 is accommodated in the hollow cylindrical receptacle 7.

[0045] The torque-limiting device 6 is designed as a slip clutch and comprises an adapter sleeve 8 arranged in a rotationally fixed manner at the first end 3a of the spindle rod 3. The adapter sleeve 8 has a hollow cylindrical design and has an inner gear 9 comprising teeth at an end facing the spindle rod 3, which teeth run on the inner circumference of the adapter sleeve 8 in the direction of the longitudinal axis X of the spindle rod 3.

[0046] The spindle rod 3 has a groove profile 10 extending along its longitudinal axis X, which meshes with the inner toothing 9 provided on the inner circumference of the adapter sleeve 8. As a result, a rotationally fixed connection between the adapter sleeve 8 and the spindle rod 3 is provided. In this case, the inner circumference of the adapter sleeve 8 tapers to form a step 8a, so that the adapter sleeve 8 is secured axially at least in one direction. Advantageously, the adapters 8 can be pushed onto the first end 3a of the spindle rod 3, wherein a mounting position of the adapter sleeve is defined by the step 8a on the inner circumference of the adapter sleeve 8.

[0047] The adapter sleeve 8 serves substantially to bridge the radial intermediate space between the first end 3a of the spindle rod 3 and the hollow cylindrical side wall 7b of the receptacle 7 of the coupling element 5, in order to produce a force-fitting coupling based on frictional forces between the spindle rod 3 and the coupling element 5. Advantageously, a reliable coupling between the spindle rod 3 and any coupling element with an optionally smaller or larger receptacle can thus be produced by appropriate adaptation of the adapter sleeve 8.

[0048] The adapter sleeve 8 is secured axially on the spindle rod 3 by a locking ring 11. The locking ring 11 is arranged in an annular groove 12 provided on the first end 3a of the spindle rod 3. The locking ring 11 is designed as an elastic O-ring. The pressing forces required to push on the adapter sleeve 8 are significantly less than the pull-off forces needed to remove the adapter sleeve 8. Advantageously, the adapter sleeve 8 can thus be easily mounted on the spindle rod 3 by pushing the adapter sleeve 8 onto the first end 3a of the spindle rod 3 with a little force. The adapter sleeve 8 is then secured axially relative to the spindle rod 3 by the locking ring 11.

[0049] Furthermore, the torque-limiting device 6 comprises a first tolerance element 13 arranged radially between the adapter sleeve 8 and the inner side of the hollow cylindrical side wall 7b of the coupling element 5 and a second tolerance element 14. The first tolerance element 13 and the second tolerance element 14 are rotationally fixed on the inner side of the hollow cylindrical side wall 7b of the coupling element 5. For this purpose, on the hollow cylindrical side wall 7b a first retaining element 15 and a second retaining element 16 are provided, which prevent a rotation of the first tolerance element 13 or of the second tolerance element 14, as explained in more detail below.

[0050] The actuating drive 1 further comprises a brake assembly 17, which serves to brake the rotational movement of the spindle rod 3. This should advantageously improve the run-out behavior when the drive of the rotary movement of the spindle rod 3 is switched off, so that a precise adjustment of a pivotable vehicle flap is made possible.

[0051] The brake assembly 17 comprises a brake housing 18 that is formed by a first brake housing part 19 and a second brake housing part 20. The first brake housing part 19 is designed as a stepped hollow cylinder and has an annular stop 19a along its inner side. The second brake housing part 20 is designed as a hollow cylinder having an annular collar 20a, which is directed radially inwards and which forms an upper side of the second brake housing part 20. The second brake housing part 20 is attached to the first brake housing part 19 like a cover, so that sufficient protection against contamination of the components present in the brake housing 18 is ensured and, at the same time, an axial displacement of the first brake housing part 19 and of the second brake housing part 20 is possible during assembly.

[0052] Furthermore, the brake assembly 17 comprises a first annular brake element 21, which is designed as an inner lamella and, on its inner diameter, comprises an inner gear 22, which engages with the groove profile 10 of the spindle rod 3. As a result, the first brake element 21 is axially displaceable along the longitudinal axis X of the spindle rod 3 and is simultaneously connected to the spindle rod 3 in a rotationally fixed manner. A second annular brake element 23 is arranged on an inner diameter of the first brake housing part 19 of the brake housing 18 in a floating manner, but an annular intermediate element 24, which is designed as a disk made of carbon fabric, is arranged in a rotationally fixed manner between the first brake element 21 and the second brake element 23. The second brake element 23 rests on the annular stop 19a of the first brake housing part 19.

[0053] The brake assembly 17 further comprises a pretensioning means 25 designed as a wave spring, which pretensions the first brake element 21 to the second brake element 23, so that the intermediate element 24 is clamped between the first brake element 21 and the second brake element 23, and a braking effect on the rotational movement of the spindle rod 3 is thus realized by means of the friction. The pretensioning means 25 is arranged axially between the collar 20a of the second brake housing part 20 and the brake elements 21, 23, wherein the second brake element 23 abuts against the annular stop 19a of the first brake housing part 19. Advantageously, the pretensioning means 25 can be pretensioned and thus concomitantly the braking force acting on the spindle rod 3 by the brake assembly 17 can be set by adjusting the relative axial position of the first brake housing part 19 and of the second brake housing part 20. After setting, the first brake housing part 19 is fixedly connected to the second brake housing part 20, in order to fix the relative axial position of the first brake housing part 19 and the second brake housing part 20.

[0054] The second brake housing part 20 has on its upper side an opening 20b delimited by the collar 20a. The torque-limiting device 8 penetrates the opening 20b in the second brake housing part 20. As a result, the brake assembly 17 and the torque-limiting device 6 overlap axially. An embodiment of a combination of the brake assembly 17 and the torque-limiting device 6 that is compact in the axial direction is thus advantageously provided.

[0055] FIG. 2 shows a frontal cross-sectional view of the torque-limiting device 6 from FIG. 1 of the actuating drive 1. In this view, it can be clearly seen that the side wall 7b of the coupling element 5 concentrically surrounds the torque-limiting device 8. It can also be seen that the first retaining element 15, which is designed as a projection in each case, and the second retaining element 18 are arranged opposite one another projecting radially inward from the inside of the side wall 7b of the coupling element 5.

[0056] The first retaining element 15 has a first lateral support surface 15a and a second lateral support surface 15b opposite the first lateral support surface 15a. Accordingly, the second retaining element 16 also has a first lateral support surface 16a and a second lateral support surface 16b opposite the first lateral support surface 16a. The first tolerance element 13 and the second tolerance element 14 are arranged between the side wall 7b of the coupling element 5 and the adapter sleeve 8 accommodated in the receptacle 7. The first tolerance element 13 is clamped between the first lateral support surface 15a of the first retaining element 15 and the first lateral support surface 16a of the second retaining element 16. As a result, a rotationally fixed connection between the first tolerance element 13 and the coupling element 5 is produced and at the same time a pretension is generated, so that the first tolerance element 13 abuts against the inner side of the side wall 7b of the coupling element 5. Accordingly, the second tolerance element 14 is clamped between the second lateral support surface 15b of the first retaining element 15 and the second lateral support surface 16b of the second retaining element 16.

[0057] FIG. 2 further shows that the adapter sleeve 8 has an inner gear 9 along an inner circumference and that the inner gear 9 meshes with the groove profile 10 of the spindle rod 3 and thus a rotationally fixed connection exists between the adapter sleeve 8 and the spindle rod 3. Advantageously, the rotationally fixed connection between the adapter sleeve 3 and the spindle rod 3 on one side and the rotationally fixed connection between the first tolerance element 13 or the second tolerance element 14 with the coupling element 5 on the other side ensures that, when a threshold value of the torque acting on the spindle rod 3 is exceeded, the spindle rod 3, together with the adapter sleeve 8, slips with respect to the first tolerance element 13 and the second tolerance element 14. This advantageously allows a well defined selection of the sliding surface 8b acting during decoupling, which accordingly allows an improved definition of the aforementioned threshold value of the torque.

[0058] FIG. 3 shows the torque-limiting device 6 from FIG. 1 in an exploded view. In this view, it can be clearly seen that the adapter sleeve 8 is designed as a hollow cylinder and has an inner gear 9 along its inner circumference. The outer circumference, on the other hand, is smooth and forms, as already explained above, an output-side sliding surface 8b.

[0059] The first tolerance element 13 and the second tolerance element 14 are designed as partially cylindrical shell segments, wherein both the first tolerance element 13 and the second tolerance element 14 have a plurality of stampings 26 on their outer surface, which abut against the inner side of the side wall 7b of the coupling element 5 when the first tolerance element 13 or the second tolerance element 14 is inserted in the receptacle 7 of the coupling element 5.

[0060] As can be clearly seen in the view shown in FIG. 3, the first end 5a of the coupling element 5 is designed in the form of a pin and comprises an external gear 27. The external gear 27 serves here for the rotationally fixed connection to a transmission, in particular, for example, to a drive gearwheel, which can mesh with the external gear 27. Furthermore, the external gear 27 can also be connected directly to a drive shaft having a corresponding opening with corresponding inner gear, so that the coupling element 5 when driven can be set in rotation.

[0061] The receptacle 7 provided at the second end 5b of the coupling element of the receptacle 7 provided, which is limited over time by the hollow cylindrical side wall 7b, is dimensioned such that the first tolerance element 13 and the second tolerance element 14 can be inserted therein. Furthermore, the second retaining element 16 designed as a projection can be seen, wherein the retaining element 16 has a chamfer 16a on its side facing the open end of the receptacle 7.

[0062] The invention has been explained above with reference to an exemplary embodiment in which the torque-limiting device comprises two tolerance elements. It is understood that the torque-limiting device may also comprise only one tolerance element or three or more tolerance elements. In this case, either only one retaining element or more than two retaining elements are provided, so that the retaining elements can rotationally fix the tolerance elements inserted in the receptacle 7.