Actuating drive including a torque limiting device

Abstract

The present invention relates to an actuating drive, in particular a spindle drive for adjusting a rotatable vehicle hood, comprising a housing (2), a spindle rod (3) rotatably mounted in the housing (2), a first coupling element (5) for driving the 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), the torque limiting device (6) comprising an adapter sleeve (8) arranged in a non-rotatable relative manner at a first end (3a) of the spindle rod (3) and a first tolerance element (13) arranged between the spindle rod (3) and the first coupling element (5). According to the invention, an actuating drive is provided which is designed to be compact and manufacturable economically in such a way that the first tolerance element (13) is non-rotatably fixed to one of the first coupling element (5) and the adapter sleeve (8).

Description

Technical Field

[0001] The present invention relates to an actuating drive, in particular for adjusting a rotatable vehicle hood, the actuating drive comprising a housing, a spindle rod rotatably mounted in the housing, a first coupling element for driving the 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. Background Art

[0002] In practice, actuating drives are known which are generally designed as linear drives for automatically adjusting vehicle hoods, such as side doors or tailgates. Thus, such an actuating drive comprises a housing which generally consists of two housing parts which are arranged concentrically one inside the other such that the length of the housing can be changed by displacing the housing parts relative to one another in the longitudinal direction. For this purpose, a spindle drive for driving the displacement of the housing parts is arranged in the housing. The spindle drive generally comprises a spindle rod rotatably mounted in the housing and a corresponding spindle nut, wherein the spindle nut is fixedly connected to one of the two housing parts and thus moves in a translational manner upon actuation of the spindle rod. The spindle rod is rotatably driven by a coupling element. The coupling element is, for example, the output shaft of an electric motor or a transmission component provided between the spindle rod and the electric motor.

[0003] In order to avoid mechanical overload caused by external forces, the actuating drive generally has a torque limiting device which is used to limit the torque transmitted from the coupling element to the spindle rod. In addition, such an actuating drive also has a braking device which is intended to prevent the unintentional adjustment of the vehicle hood by external mechanical forces and also to define the jitter behavior of the actuating drive. The braking device and the torque limiting device are advantageously arranged axially in series and require a large installation space within the housing.

[0004] EP 3 032 020 B1 shows an actuating drive for automatically adjusting a vehicle door, in particular a tailgate, the actuating drive comprising a housing, wherein the housing comprises a first tubular housing part and a second tubular housing part which are movable relative to one another in a telescopic manner. The actuating drive further comprises a spindle rod rotatably mounted in the housing, a coupling element designed as a housing, and a torque limiting device arranged between the coupling element and the spindle rod for limiting the torque transmitted from the coupling element to the spindle rod. The torque limiting device comprises an adaptor designed as a locating pin, wherein the adaptor is arranged between the spindle rod and the coupling element. A disadvantage of the shown actuating drive is that the adaptor has a rather large structural volume and thus a high manufacturing cost due to the required amount of material. In addition, due to friction, the coupling element has to be hardened, which also increases the manufacturing cost.

[0005] DE 36 28 285 A1 shows an electro - actuated drive, which includes a housing, a spindle rod rotatably mounted in the housing, a rotor for driving the rotational movement of the spindle rod, and a torque - limiting device arranged between the rotor and the spindle rod for limiting the torque transmitted from the rotor to the spindle rod. The torque - limiting device includes a flange and an armature. The flange is arranged at the first end of the spindle rod in a non - rotatable (drehfest) manner, and the armature is fixed to the flange via a threaded connection. A cylindrical protrusion is provided on the armature, and this protrusion extends frictionally into a corresponding recess in the rotor. One disadvantage of the shown actuated drive is that the torque - limiting device occupies a large installation space and requires high material costs and corresponding high costs.

[0006] DE 195 45 379C1 shows an actuated drive, which includes a housing and a spindle rod rotatably mounted in the housing, wherein the spindle rod is connected in a non - rotatable manner to a motor shaft for driving the rotational movement of the spindle rod.

[0007] EP 2 159 438 A1 shows a torque - limiting device, which includes a pot - shaped coupling part formed at the first end of a spindle rod and an output shaft protruding into the pot - shaped coupling part for driving the rotational movement of the spindle rod. A tolerance element for limiting the tolerance of the limit value of the torque transmitted from the output shaft to the spindle rod is arranged radially between the coupling part of the spindle rod and the output shaft. One disadvantage of the shown torque - limiting device is that the tolerance element is connected to the output shaft and the coupling part of the spindle rod only by friction, so that an accurate definition of the corresponding limit value of torque transmission cannot be ensured.

[0008] DE 10 2008 031 228 A1 shows a spindle drive for adjusting a rotatable vehicle hood, which includes a housing, a spindle rod rotatably mounted in the housing, a transmission shaft for driving the rotational movement of the spindle rod, and a torque - limiting device arranged between the transmission shaft and the spindle rod for limiting the torque transmitted from the first transmission shaft to the spindle rod. Among them, the torque - limiting device includes an adapter sleeve arranged at the first end of the spindle rod in a non - rotatable manner and a tolerance element arranged between the spindle rod and the adapter sleeve and designed as a tolerance ring. One disadvantage of the shown spindle drive is that the tolerance ring is fixed to the transmission shaft and the adapter sleeve only by friction, so that there is no clearly defined torque threshold at which the torque - limiting device causes decoupling between the transmission shaft and the spindle rod.

[0009] US2014 / 0166423 A1 shows a tolerance element, wherein the tolerance element can be arranged radially between an inner member and an outer member to limit the torque transmission between the two members.

[0010] US2011 / 0290050 A1 shows an actuating drive, which includes a housing and a spindle rod rotatably mounted in the housing, wherein the spindle rod can be rotatably driven by being coupled to an electric motor.

[0011] DE 10 2018 100 562 A1 shows an actuating drive for adjusting a rotatable vehicle hood, which includes a housing and a spindle rod rotatably mounted in the housing, wherein the spindle rod is rotatably driven via a drive device.

[0012] DE 10 2008 008 541 B3 shows an operating device for a valve or a joint, which has a torque limiting device that can be controlled by a cam and a rocker arm.

[0013] EP 3 232 076 A1 shows a coupling element designed as a helical elastic element, which can be arranged between a first end of the spindle rod and a drive-side elastic cup and is used for torque limitation. Summary of the Invention

[0014] The object of the present invention is to provide a compact actuating drive that can be manufactured at low cost.

[0015] According to the present invention, this object is achieved by an actuating drive having the features according to the present invention.

[0016] According to one aspect of the present invention, there is provided an actuating drive, in particular a spindle drive for adjusting a rotatable vehicle hood, which includes a housing, a spindle rod rotatably mounted in the housing, a first coupling element for driving the 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 includes an adapter sleeve arranged at a first end of the spindle rod in a non-rotatable relative manner and a first tolerance element arranged between the spindle rod and the first coupling element. The actuating drive according to the present invention is characterized in that the first tolerance element is non-rotatably fixed to one of the first coupling element and the adapter sleeve. Advantageously, an actuating drive is thus provided that has a clearly defined torque threshold at which the torque limiting device causes decoupling between the coupling element and the spindle rod. In addition, by using an adapter sleeve, a tolerance element with a reduced thickness can be used, wherein the friction characteristics and thus the torque threshold can be selected by configuring the surface of the tolerance element. Furthermore, there is no need to harden the coupling element or the adapter sleeve, thereby greatly reducing the manufacturing cost.

[0017] Particularly preferably, one of the first coupling element and the mating part includes at least one first retaining element. The first retaining element preferably prevents rotational movement of the first tolerance element relative to one of the first coupling element and the mating part in at least one rotational direction by form-locking.

[0018] In an advantageous embodiment, the first retaining element is embodied as a projection having a first lateral support surface and a second lateral support surface opposite the first lateral support surface. Preferably, the first retaining element is integrally formed with one of the first coupling element and the mating part. Advantageously, when manufacturing the first coupling element or the mating part, the retaining element can be integrally molded from plastic in an injection molding process, for example in a common manufacturing step. In particular, it is advantageously ensured that the retaining element does not become detached from one of the first coupling element and the mating part.

[0019] In a particularly preferred refinement, it is provided that the first tolerance element is supported at least on the first lateral support surface of the first retaining element. Thereby, rotational movement of the first tolerance element in the direction of the first lateral support surface is advantageously prevented by form-locking, since the first tolerance element abuts against the first lateral support surface and cannot rotate further.

[0020] In a first preferred embodiment, the first tolerance element is supported on the first lateral support surface and the second lateral support surface of the first retaining element. Advantageously, an anti-rotational connection is thereby produced between the first tolerance element and one of the coupling element and the mating part for both rotational directions.

[0021] The first tolerance element is preferably designed as a partial cylindrical shell segment. The first tolerance element advantageously has an indentation directed in the radial direction towards one of the coupling element and the mating part. Advantageously, radial preloading is achieved between the coupling element and the mating part by means of the indentation. Starting from a limit value of the torque, the tolerance element slides relative to the other of the coupling element and the mating part, the limit value of the torque being substantially defined by the surface of the tolerance element and the preloading produced via the indentation.

[0022] Particularly preferably, the torque limiting device includes a second tolerance element. In a particularly preferred refinement, it is provided that the second tolerance element is supported at least on the second lateral support surface of the first retaining element. By providing the second tolerance element, an improved distribution of the frictional forces to be absorbed, which result from the friction between the tolerance element and the other of the coupling element and the mating part, is advantageously achieved.

[0023] In a particularly preferred refinement, one of the first coupling element and the mating part has at least one second retaining element. In a first preferred embodiment, the second retaining element is arranged opposite the first retaining element. In an advantageous embodiment, the second retaining element is designed as a projection having a first lateral support surface and a second lateral support surface opposite the first lateral support surface. The second retaining element is preferably integrally formed with one of the first coupling element and the mating part. Advantageously, the two tolerance elements can thus be arranged symmetrically with respect to one another and are non-rotatably fixed to one of the coupling element and the mating part.

[0024] In an alternative refinement, the first tolerance element is particularly advantageously supported on the first lateral support surface of the first retaining element and on the first lateral support surface of the second retaining element. Advantageously, the first tolerance element is non-rotatably fixed between the first retaining element and the second retaining element and is non-rotatably fixed to one of the coupling element and the mating part.

[0025] The second tolerance element is advantageously supported on the second lateral support surface of the first retaining element and on the second lateral support surface of the second retaining element. Advantageously, the second tolerance element is non-rotatably fixed between the first retaining element and the second retaining element and is non-rotatably fixed to one of the coupling element and the mating part. The first tolerance element and the second tolerance element are preferably spaced apart from one another by the first retaining element and the second retaining element.

[0026] In a preferred embodiment of the actuating drive, it is provided that the first coupling element has a hollow cylindrical receiving part which faces the spindle rod and has a base and a side wall. Particularly preferably, the base is annular. Advantageously, the inner side surface of the side wall facing the receiving part forms a friction surface via which the frictional force transmission between the coupling element and the spindle rod or the mating part takes place.

[0027] In a preferred refinement, the first tolerance element and the mating part are at least partially received in the hollow cylindrical receiving part. Particularly preferably, the first tolerance element and the mating part are completely received in the hollow cylindrical receiving part. This advantageously enables a particularly compact design of the torque limiting device, so that the overall length of the actuating drive can be reduced.

[0028] The first retaining element is preferably arranged on the inner side surface of the side wall of the hollow cylindrical receiving part. Advantageously, the first tolerance element can thus be non-rotatably fixed to the coupling element. Advantageously, the first tolerance element lies flat against the inner side surface of the side wall of the hollow cylindrical receiving part and is fixed with respect to rotation by the first retaining element.

[0029] In a preferred embodiment, it is provided that a brake assembly is arranged in the housing, wherein the brake assembly includes a brake housing. Preferably, the brake housing is arranged concentrically around the first end of the main spindle. The brake assembly is advantageously used to brake the rotational movement of the main spindle in order to control the jitter behavior when the motor driving the main spindle or the drive coupling element is switched off.

[0030] Preferably, the first coupling element at least partially passes through the brake housing of the brake assembly. This enables a compact design of the actuating drive, since the brake assembly and the torque limiting device thus axially overlap and the overlapping region thus shortens the length of the actuating drive.

[0031] According to another aspect of the present invention, there is provided an actuating drive, in particular a main spindle drive for adjusting a rotatable vehicle hood. The actuating drive includes a housing, a main spindle rotatably mounted in the housing, and a first coupling element for driving the rotational movement of the main spindle. In addition, the actuating drive includes a torque limiting device and a brake assembly, the torque limiting device being arranged between the first coupling element and the main spindle for limiting the torque transmitted from the first coupling element to the main spindle, wherein the brake assembly includes a brake housing. The actuating drive according to the present invention is characterized in that the torque limiting device and the brake assembly at least partially axially overlap. Advantageously, compared with the actuating drives known in the prior art having a brake assembly and a torque limiting device, the actuating drive has a shortened overall length, so that the actuating drive according to the present invention has a compact design.

[0032] In an advantageous embodiment, the brake assembly includes a first brake element, wherein the first brake element is non-rotatably connected to the main spindle. The first brake element is preferably designed as an annular inner thin plate structure and has an inner tooth portion on its inner diameter. Particularly preferably, the main spindle has a groove profile that meshes with the inner tooth portion of the first brake element. Advantageously, a reliable non-rotatable connection is thus produced between the main spindle and the first brake element. However, further advantageously, the first brake element can thus move axially relative to the main spindle.

[0033] In a preferred embodiment, the brake assembly includes a second brake element, wherein the second brake element is non-rotatably connected to the brake housing. The second brake element is advantageously designed as an annular disc structure with a plurality of radially outwardly directed protrusions, wherein the protrusions pass through the slot-shaped recesses of the brake housing. Advantageously, the second brake element is non-rotatably connected to the spindle shaft but can be axially displaced along the longitudinal axis of the spindle shaft. Advantageously, the first brake element and the second brake element can be preloaded against each other and thus the braking force acting on the spindle shaft can be controlled. In a preferred refinement, an intermediate element is arranged between the first brake element and the second brake element. The intermediate element is preferably designed as an annular disc structure made of carbon fiber, in particular a carbon fiber mesh structure embedded in plastic.

[0034] In a preferred embodiment, the brake assembly includes a preloading device for axially preloading the first brake element against the second brake element to generate a braking force. Particularly preferably, the preloading device is designed as a corrugated elastic element. Preferably, the preloading device concentrically surrounds the first end of the spindle shaft. Advantageously, by means of the preloading device, a predetermined braking force is generated by friction between the first brake element and the second brake element, and the predetermined braking force is preferably transmitted via the intermediate element.

[0035] The torque limiting device preferably includes an adapter sleeve and a tolerance element, the adapter sleeve being non-rotatably arranged at the first end of the spindle shaft, wherein the tolerance element is radially arranged between the adapter sleeve and the first coupling element. Particularly preferably, the preloading device at least partially axially overlaps with one of the adapter sleeve and the tolerance element. Advantageously, the torque limiting device is partially inserted into the brake assembly through an opening provided in the brake housing. Advantageously, by means of the overlap of the axially arranged torque limiting device and the brake assembly, the functions of the torque limiting device and the brake assembly are fully realized, and a compact design of the actuating drive is achieved.

[0036] Other advantages, features and refinements of the invention become apparent from the following description of the preferred embodiments. Description of the Drawings

[0037] The invention will now be explained in more detail using preferred exemplary embodiments with reference to the accompanying drawings.

[0038] Figure 1 A preferred exemplary embodiment of the actuating drive is shown in a side sectional view,

[0039] Figure 2 showing the Figure 1 front sectional view of the torque limiting device of the actuating drive,

[0040] Figure 3 is shown in an exploded view Figure 1 of the torque limiting device. DETAILED DESCRIPTION

[0041] Figure 1 A preferred exemplary embodiment of the actuating drive 1 is shown in a side cross - section. The actuating drive 1 shown in part includes a housing 2, wherein the housing 2 is in the form of a hollow cylinder and concentrically surrounds a main spindle 3. The main spindle 3 is rotatably mounted in the housing 2 via a ball bearing 4.

[0042] In one section (not shown here), the main spindle 3 has a drive thread that meshes with a main spindle nut (not shown here) with a corresponding internal thread, such that when the main spindle 3 rotates, the main spindle nut can be displaced together with the housing part of the housing 2 in the direction of the longitudinal axis X of the main spindle 3.

[0043] To drive the rotational movement of the main spindle 3, a coupling element 5 is coupled to the first end 3a of the main spindle 3, wherein a torque limiting device 6 is arranged between the coupling element 5 and the main spindle 3, and the torque limiting device 6 limits the torque transmitted from the first coupling element 5 to the main spindle 3. Advantageously, the torque limiting device 6 can be used to decouple excessive external forces from the transmission section or the electric motor, such external forces occurring, for example, through an action on the vehicle hood (such as a collision with an obstacle). This can advantageously 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 includes a first end 5a facing away from the main spindle 3, which first end 5a is designed in the form of a pin and can be connected to a transmission (not shown here) or to the output shaft of an electric motor. In addition, the coupling element 5 includes a second end 5b facing the main spindle 3, which second end 5b is designed as a pot - shaped and forms a hollow cylindrical receiving portion 7. The hollow cylindrical receiving portion 7 has an annular base 7a and a hollow cylindrical side wall 7b. The torque limiting device 6 is received in the hollow cylindrical receiving portion 7.

[0045] The torque limiting device 6 is designed as a slip clutch and includes an adapter sleeve 8 arranged in a non - rotatable relative manner at the first end 3a of the main spindle 3. The adapter sleeve 8 has a hollow cylindrical design and has an internal tooth portion 9, which internal tooth portion 9 includes teeth at the end facing the main spindle 3, and these teeth extend in the direction of the longitudinal axis X of the main spindle 3 on the inner circumference of the adapter sleeve 8.

[0046] The main spindle shaft 3 has a groove profile 10 extending along its longitudinal axis X, and the groove profile 10 meshes with an internal tooth portion 9 provided on the inner circumference of the adapter sleeve 8. As a result, a non-rotatable relative connection is provided between the adapter sleeve 8 and the main spindle shaft 3. In this case, the inner circumference of the adapter sleeve 8 tapers to form a stepped portion 8a, so that the adapter sleeve 8 is axially fixed at least in one direction. Advantageously, the adapter sleeve 8 can be pushed onto the first end 3a of the main spindle shaft 3, and the mounting position of the adapter sleeve is defined by the stepped portion 8a on the inner circumference of the adapter sleeve 8.

[0047] The adapter sleeve 8 is basically used to bridge the radial intermediate space between the first end 3a of the main spindle shaft 3 and the hollow cylindrical side wall 7b of the receiving portion 7 of the coupling element 5, so as to produce a force-locking coupling based on the frictional force between the main spindle shaft 3 and the coupling element 5. Advantageously, a reliable coupling between the main spindle shaft 3 and any coupling element with an optionally smaller or larger receiving portion can be produced by appropriate adaptation of the adapter sleeve 8.

[0048] The adapter sleeve 8 is axially fixed to the main spindle shaft 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 main spindle shaft 3. The locking ring 11 is designed as an elastic O-ring. The pressure required to push the adapter sleeve 8 is significantly less than the pull-off force required to remove the adapter sleeve 8. Advantageously, the adapter sleeve 8 can be easily mounted on the main spindle shaft 3 by pushing the adapter sleeve 8 onto the first end 3a of the main spindle shaft 3 with a very small force. Then, the adapter sleeve 8 is axially fixed relative to the main spindle shaft 3 by the locking ring 11.

[0049] In addition, the torque limiting device 6 includes a first tolerance element 13 and a second tolerance element 14. The first tolerance element 13 is radially arranged between the adapter sleeve 8 and the inner side surface of the hollow cylindrical side wall 7b of the coupling element 5. The first tolerance element 13 and the second tolerance element 14 are non-rotatably fixed to the inner side surface of the hollow cylindrical side wall 7b of the coupling element 5. For this purpose, a first retaining element 15 and a second retaining element 16 are provided on the hollow cylindrical side wall 7b, and the first retaining element 15 and the second retaining element 16 prevent the rotation of the first tolerance element 13 or the second tolerance element 14, as will be described in more detail below.

[0050] The actuating drive 1 also includes a brake assembly 17 for braking the rotational movement of the main spindle shaft 3. This should advantageously improve the jitter behavior when the drive of the rotational movement of the main spindle shaft 3 is turned off, so that precise adjustment of the rotatable vehicle hood can be achieved.

[0051] The brake assembly 17 includes a brake housing 18 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 cylindrical structure and has an annular stop portion 19a along its inner side surface. The second brake housing part 20 is designed as a hollow cylindrical structure with an annular collar 20a, which is radially inwardly directed and forms the upper side portion 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, thereby ensuring sufficient protection of the components present in the brake housing 18 from contamination. At the same time, the first brake housing part 19 and the second brake housing part 20 can be axially displaced during assembly.

[0052] In addition, the brake assembly 17 includes a first annular brake element 21, which is designed as an inner thin sheet structure and includes an inner tooth portion 22 on its inner diameter, and the inner tooth portion 22 meshes with the groove profile portion 10 of the main spindle 3. As a result, the first brake element 21 can be axially displaced along the longitudinal axis X of the main spindle 3 and is simultaneously connected to the main spindle 3 in a non-rotatable relative manner. The second annular brake element 23 is arranged in a floating manner on the inner diameter of the first brake housing part 19 of the brake housing 18, and an annular intermediate element 24, which is designed as a disk structure made of carbon fiber, is arranged in a non-rotatable relative manner between the first brake element 21 and the second brake element 23. The second brake element 23 abuts against the annular stop portion 19a of the first brake housing part 19.

[0053] The brake assembly 17 further includes a preloading device 25, which is designed as a wave spring, and preloads the first brake element 21 against 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, thereby achieving a braking effect on the rotational movement of the main spindle 3 by means of friction. The preloading device 25 is axially arranged between the collar 20a of the second brake housing part 20 and the brake elements 21, 23, where the second brake element 23 abuts against the annular stop portion 19a of the first brake housing part 19. Advantageously, the preloading device 25 can be preloaded, and thereby the braking force exerted by the brake assembly 17 on the main spindle 3 can be set by adjusting the relative axial position of the first brake housing part 19 and 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 an opening 20b defined by a collar 20a on its upper side. The torque limiting device 6 passes through 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. Thereby, an embodiment of a combination of the brake assembly 17 and the torque limiting device 6 that is compact in the axial direction is advantageously provided.

[0055] Figure 2 A front cross-sectional view of the torque limiting device 6 of the actuating drive 1 is shown. In this view, it can be clearly seen that the side wall 7b of the coupling element 5 concentrically surrounds the torque limiting device 6. It can also be seen that the first holding element 15 and the second holding element 16, which are each designed as a protrusion, are arranged opposite each other and project radially inwards from the inner side surface of the side wall 7b of the coupling element 5. Figure 1

[0056] The first holding 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 holding 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 received in the receiving portion 7. The first tolerance element 13 is clamped between the first lateral support surface 15a of the first holding element 15 and the first lateral support surface 16a of the second holding element 16. As a result, a non-rotatable connection is produced between the first tolerance element 13 and the coupling element 5, and at the same time a pre-tension is produced such that the first tolerance element 13 abuts against the inner side surface 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 holding element 15 and the second lateral support surface 16b of the second holding element 16.

[0057] Figure 2 It is also shown that the adapter sleeve 8 has an internal tooth portion 9 along its inner circumference, and the internal tooth portion 9 meshes with the groove profile portion 10 of the main spindle 3. Accordingly, a non-rotatable connection exists between the adapter sleeve 8 and the main spindle 3. Advantageously, the non-rotatable connection between the adapter sleeve 8 and the main spindle 3 on the one hand and the non-rotatable connection between the first tolerance element 13 or the second tolerance element 14 and the coupling element 5 on the other hand ensure that when the torque acting on the main spindle 3 exceeds a threshold value, the main spindle 3 and the adapter sleeve 8 slide relative to the first tolerance element 13 and the second tolerance element 14 together. This advantageously enables a clear selection of the sliding surface 8b that acts during decoupling, thereby allowing an improved definition of the above-mentioned torque threshold.

[0058] Figure 3 Figure 1 Is shown in an exploded view Figure 1The torque limiting device 6. As can be clearly seen in this view, the adapter sleeve 8 is designed as a hollow cylindrical structure and has an internal tooth portion 9 along its inner circumference. On the other hand, the outer circumference is smooth and forms the output side sliding surface 8b as already described above.

[0059] The first tolerance element 13 and the second tolerance element 14 are designed as partial cylindrical shell segments, and both the first tolerance element 13 and the second tolerance element 14 have a plurality of indentations 26 on their outer surfaces, and when the first tolerance element 13 or the second tolerance element 14 is inserted into the receiving portion 7 of the coupling element 5, these indentations 26 abut against the inner side surface of the side wall 7b of the coupling element 5.

[0060] As can be clearly seen in the view as Figure 3 shown, the first end portion 5a of the coupling element 5 is designed in the form of a pin and includes an external tooth portion 27. The external tooth portion 27 is used here for non-rotatably connecting to a transmission device that can mesh with the external tooth portion 27, in particular, for example, a drive gear. In addition, the external tooth portion 27 can also be directly connected to a drive shaft that has an opening corresponding to the corresponding internal tooth portion, so that the coupling element 5 can be set to rotate when being driven.

[0061] The size of the receiving portion 7 provided at the second end portion 5b of the coupling element, which is currently defined by the hollow cylindrical side wall 7b, is determined such that the first tolerance element 13 and the second tolerance element 14 can be inserted therein. In addition, the second retaining element 16 designed as a protrusion can be seen, and the second retaining element 16 has a chamfer 16a on the side facing the opening end of the receiving portion 7.

[0062] The present invention has been explained above with reference to an exemplary embodiment, in which the torque limiting device includes two tolerance elements. It can be understood that the torque limiting device can also include only one tolerance element or three or more tolerance elements. In this case, only one retaining element can be provided, or two or more retaining elements can be provided, so that the retaining element can non-rotatably connect the tolerance element inserted into the receiving portion 7.

Claims

1. An actuating drive for adjusting a rotatable vehicle hood, comprising: a housing (2); a spindle rod (3) rotatably mounted in the housing (2); a first coupling element (5) for driving the 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), wherein the torque limiting device (6) comprises: an adapter sleeve (8) arranged in a non-rotatable relative manner at a first end (3a) of the spindle rod (3); and a first tolerance element (13) arranged between the spindle rod (3) and the first coupling element (5), wherein the first tolerance element (13) is non-rotatably fixed to one of the first coupling element (5) and the adapter sleeve (8), wherein one of the first coupling element (5) and the adapter sleeve (8) has at least one first retaining element (15), wherein the first retaining element (15) is designed as a protrusion having a first lateral support surface (15a) and a second lateral support surface (15b), wherein the first retaining element (15) is integrally formed with one of the first coupling element (5) and the adapter sleeve (8), wherein the first tolerance element (13) is supported on the first lateral support surface (15a) and the second lateral support surface (15b).

2. The actuating driver according to claim 1, characterized in that, The first tolerance element (13) is designed as a partially cylindrical shell element.

3. The actuating driver according to claim 1, characterized in that, The torque limiting device (6) comprises a second tolerance element (14).

4. The actuation driver according to claim 3, characterized in that, The second tolerance element (14) is at least supported on the second lateral support surface (15b) of the first retaining element (15).

5. The actuating driver according to claim 1, characterized in that, One of the first coupling element (5) and the adapter sleeve (8) comprises at least one second retaining element (16), wherein the second retaining element (16) is designed as a protrusion having a first lateral support surface (16a) and a second lateral support surface (16b).

6. The actuating driver according to claim 5, wherein, The first tolerance element (13) is supported on 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).

7. The actuating driver according to claim 1, characterized in that, The first coupling element (5) has a hollow cylindrical receiving portion (7) facing the spindle rod (3) and having a base (7a) and a side wall (7b).

8. The actuating driver according to claim 7, characterized in that, The first tolerance element (13) and the adapter sleeve (8) are at least partially received in the hollow cylindrical receiving portion (7).

9. The actuating drive according to claim 8, wherein, The first retaining element (15) is arranged on the inner side surface of the side wall (7b) of the hollow cylindrical receiving portion (7).

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