Actuating device

Abstract

The invention relates to an actuating device (10) for a superordinate, i.e. not belonging to the actuating device (10), movable assembly, in particular for a vehicle part that is movable relative to a body of a vehicle, the actuating device at least comprising a drive arrangement (12) with a drive unit (14), a transmission unit (20) arranged in a housing (16) and an actuating element (22) which can be displaced relative to the drive arrangement (12) by means of the drive unit (14), wherein the drive unit (14) has an output shaft (24) which is mounted in the housing (16) at least by means of an axial bearing (32) for compensation of play and / or tolerance, wherein a curved shaft end (30) of the output shaft (24) rests, by means of a convex running surface (31), on a thrust washer (36) which is supported on an elastomer element (34) arranged in the housing (16), wherein the thrust washer (36) has, for contacting the curved shaft end (30) of the output shaft (24), a concave thrust surface (42) designed to be complementary to the convex running surface (31) of the shaft end (30) on at least the end face (38) facing the output shaft (24).

Description

[0001] Adjusting device

[0002] Description

[0003] The invention relates to an actuating device for a higher-level, i.e. not belonging to the actuating device, movable assembly, in particular for a vehicle part that is movable relative to a body of a vehicle, at least comprising a drive arrangement with a drive unit, a gear unit arranged in a housing and an actuating element that can be displaced relative to the drive arrangement by means of the drive unit, an actuating element that can be displaced relative to the drive arrangement by means of the drive unit, wherein the drive unit has an output shaft that is mounted in the housing at least by means of an axial bearing for play and / or tolerance compensation.

[0004] Such an actuating device is known, for example, from DE 102016218226 A1 and is used, among other things, for the automatic opening and closing of doors and / or tailgates of motor vehicles. The gear unit can exert a considerable axial force on the output shaft of the electric motor. Therefore, the prior art provides for a play-free axial bearing for the output shaft, which consists of an elastic element and a flat thrust washer adjacent to it. A disadvantage of this approach, however, is the lack of radial support for the freely projecting shaft end of the output shaft, since the output shaft can bend due to radial gear forces, with the result that the center distances of the gear can change. This, in turn, can lead to a deterioration in acoustic performance and, on the other hand, to increased wear.

[0005] Other solutions therefore propose additional radial support for the shaft end. For example, DE 195 13 970 A1 discloses arranging the shaft end in a spring-loaded, cup-shaped abutment, which prevents the shaft from deflecting sideways. However, such a mounting leads to a mechanical overdetermination of the bearing, which in turn can lead to undesirable noise, increased wear, and possibly damage to the actuator.

[0006] It is therefore an object of the invention to provide an actuating device with an improved axial bearing and a dynamic radial support.

[0007] This object is achieved according to the invention by an adjusting device of the type mentioned at the outset, in which a curved shaft end of the output shaft rests with a convex running surface on a thrust washer which is supported on an elastomer element arranged in the housing, wherein the thrust washer has a concave running surface complementary to the convex running surface of the shaft end for the contact of the curved shaft end of the output shaft on at least the end face facing the output shaft.

[0008] The running surface and the contact surface are matched to enable a self-centering effect and more even load distribution. This contributes to an extended service life of the bearing.

[0009] Preferably, the convex running surface of the shaft end is arranged at least almost centrally to the concave running surface of the thrust washer in the unloaded state.

[0010] The at least nearly central arrangement of the convex running surface of the shaft end to the concave contact surface ensures an optimal starting position for load absorption in the unloaded state and contributes to even load distribution. This design enables precise guidance of the motor shaft even under dynamic loads, resulting in improved operational reliability and performance of the actuator.

[0011] According to an advantageous development of the invention, the contact surface of the contact washer and the running surface of the shaft end are designed to be complementary to one another in such a way that, upon radial deflection of the shaft end from a center of the concave contact surface, a force counteracting the deflection can be generated on the shaft end by elastic deformation of the elastomer element.

[0012] If the free shaft end of the output shaft is deflected due to radial forces from the gear unit, the shaft end shifts away from the center of the thrust washer and its concave running surface. This lateral displacement of the shaft end leads to compression, i.e., elastic deformation of the elastomer element, which creates a force on the shaft end that counteracts the deflection, reducing the deflection and centering the shaft end. The centering of the shaft end is thus achieved exclusively by the forces counteracting the deflection, without the need for over-determination associated with forced guidance.

[0013] The bearing system under load can be influenced by the geometric design of the thrust washer as well as by the design (geometrically and in terms of material properties) of the elastic elastomer element.

[0014] Preferably, the elastomer element has a progressive force-displacement characteristic curve. This results in a non-constant spring characteristic curve of the elastomer element, with the elastomer element exerting a low preload force on the output shaft in a first characteristic range of the force-displacement characteristic curve. Friction in this range is advantageously low.

[0015] A flat first characteristic curve section of the force-displacement curve can be easily achieved by having the elastomer element with a cross-section that decreases toward the housing. This creates a helix angle on the outer side of the elastomer element, which has a significant influence on the course of the first characteristic curve section, since the elastomer element initially deforms elastically upon compression, so that the outer side rests against the adjacent side surfaces of the housing.

[0016] According to an advantageous development of the invention, the elastomer element has an uneven structure with depressions on an end face facing the housing, into which the material surrounding the depressions can be elastically deformed upon compression of the elastomer element. The material surrounding the depressions forms tooth-like protrusions that can expand into the spaces created by the depressions. As soon as the spaces are filled, the characteristic curve of the elastomer element rises sharply, and a transition to an ideally stiff, second characteristic range of the elastomer element occurs.

[0017] Within the scope of the invention, other structures forming free spaces are conceivable.

[0018] If the thrust washer is arranged in a recess of the elastomer element according to an advantageous embodiment of the invention, the thrust washer can be noise-decoupled from the housing.

[0019] A preferably radial support of the thrust washer can be achieved, for example, by providing at least the end face of the thrust washer facing the elastomer element with a central projection for radial support against the recess in the elastomer element that complements the projection. This prevents radial displacement of the thrust washer due to the forces acting upon it.

[0020] If, according to an advantageous development, the thrust washer has a concave running surface on both ends, assembly can be significantly simplified, since the identical design of the ends reliably prevents misalignment. The thrust washer preferably has a central projection on both ends.

[0021] According to an advantageous embodiment, the drive arrangement can be provided with a connecting unit for connection to another higher-level assembly, while the actuating element is provided with a further connecting unit for connecting the actuating element to the higher-level assembly. The actuating element can, for example, be an axially displaceable spindle, the linear movement of which is generated by a gear element of the gear unit. It is also conceivable to transmit a rotational movement of the gear unit to an axially fixed spindle with an axially displaceable spindle nut, wherein an actuating element connected to the higher-level assembly is articulated to the spindle nut.

[0022] Preferably, the adjusting element is provided in the form of a spindle which can be displaced relative to the drive arrangement by means of the drive unit.

[0023] The invention further relates to a motor vehicle with a movable vehicle part as a higher-level assembly and with a body as a further higher-level assembly, wherein the movable vehicle part is equipped with an actuating device according to the invention. The invention will be explained in more detail below using an exemplary embodiment with reference to the accompanying drawings. It shows:

[0024] Figure 1 is a partially sectioned side view of an adjusting device according to the invention;

[0025] Figure 2 shows an enlarged section A of Figure 1;

[0026] Figure 3 is an enlarged view of the axial bearing of the

[0027] Adjusting device from Figures 1 and 2 and

[0028] Figure 4 is an exploded view of the axial bearing of the

[0029] Adjusting device from Figures 1 and 2.

[0030] Figure 1 shows a partially sectioned side view of an actuating device according to the invention. It serves, for example, to move a movable vehicle part (not shown) as a higher-level assembly relative to a vehicle body, which represents another higher-level assembly. The movable vehicle part can be, for example, a vehicle door or a vehicle tailgate. The actuating device 10 comprises a drive arrangement 12 with a drive unit 14, for example, an electric motor, and optionally a motion state sensor (not shown), for example, a Hall sensor, for detecting the motion state of the drive unit 14.

[0031] In the actuating device shown in Figure 1, the electric motor 14 is flanged directly to a housing 16. Other embodiments in which the electric motor 14 is accommodated in the housing 16 are also possible. The housing 16 here surrounds a gear unit 20, which comprises at least one worm 18 as the first gear element and a non-visible gear wheel as the second gear element. The actuating device 10 further comprises an actuating element 22, which in the illustrated embodiment is designed as a spindle and which can be displaced relative to the drive arrangement 12, i.e., relative to the housing 16, by means of the drive unit 14.

[0032] The actuating element 22 is hinged to the movable vehicle part by means of a bracket, while the housing 16 of the actuating device 10 is connected to the vehicle body via a gimbal mount 26. The degrees of freedom of movement provided by the gimbal mount 24 reliably prevent tilting of the actuating device 10.

[0033] Figure 2 shows an enlarged section A of the adjusting device 10 shown in Figure 10. As can be seen in Figures 1 and 2, an output shaft 24 of the drive unit 14 carries the worm 18, which meshes with the gear. In this exemplary embodiment, the gear surrounds the spindle 22 as a second gear element. The gear is connected radially inwardly to a spindle nut, which threadably engages an external thread of the spindle 22 in such a way that a rotary movement of the drive unit 14 is converted into a linear movement of the spindle 22 in its longitudinal direction.

[0034] To control the operation of the drive unit 14, a control unit (not shown) is also assigned to the drive assembly 12. Output signals from the motion state sensor can be fed to the control unit via a signal input. Furthermore, the output signals from an obstacle detection sensor can be fed to the control unit via a signal input.

[0035] If the control unit determines, based on the signals from the motion state sensor, that the movable vehicle part is being moved manually, it controls the drive unit 14 to assist the desired movement, i.e., similar to a power steering system. The proportion of the force required to move the movable vehicle part, which is then taken over by the drive unit 14, can be adjusted as desired, but is advantageously selected such that the vehicle part can be actuated with a low force in the order of 5 to 10 N, even when the vehicle is on an incline or in a sideways position.

[0036] The worm 18 is mounted directly on the output shaft 28 of the electric motor 14, i.e., without, for example, flexible couplings being arranged between the worm 18 and the output shaft 24 connected to a rotor of the electric motor 14. Alternatively, the worm 18 can be formed in one piece or integrally with the output shaft 24.

[0037] Furthermore, the output shaft 24 of the drive unit 14 is rotatably supported by two rotary bearings (not shown). A shaft end of the output shaft 24, which is oriented downwards in Figure 1 and not shown, can be in axial contact with a ball, wherein the ball is mounted in a shell formed by a drive housing 28. In this way, the output shaft 24 is provided with an axial bearing relative to which the output shaft 24 can nevertheless rotate with low loss. At a curved shaft end 30 of the output shaft 24, shown at the top in Figure 1, the output shaft 24 is in contact with an axial bearing 32, which is designed to accommodate, for example, temperature-related changes in length of the output shaft 24 in the axial direction and to compensate for play and tolerances.

[0038] The axial bearing 32, which is shown enlarged in Figures 3 and 4, comprises an elastically deformable elastomer element 34 arranged in the housing 16 and a thrust washer 36 supported thereon, against which the curved shaft end 30 rests in a preloaded manner and which is arranged in a recess 46 of the elastomer element 34 adapted to the shape of the thrust washer 36. The recess 46 is designed such that side surfaces 47, 49 of the thrust washer 36 are encompassed by the elastomer element 34, whereby the thrust washer 36 is noise-decoupled from the housing 16. The elastomer element 34 and the thrust washer 36 are essentially rectangular. However, other shapes, such as a disk-shaped configuration, are conceivable.

[0039] The shaft end 30 is designed to project freely, so that radial forces from the gear unit 20 can cause the shaft end 30 to bend. This can change the center distances of the gear unit 20, which can lead to a deterioration in acoustic performance and, on the other hand, increased wear.

[0040] To avoid these disadvantages, the thrust washer 36 has a concave thrust surface 42 adapted to the shape of the shaft end 30 for engaging a convex running surface 31 of the curved shaft end 30 on at least the first end face 38 facing the output shaft 24. The convex running surface 31 of the shaft end 30 and the concave thrust surface 42 of the thrust washer 36 are thus complementary to one another. As can be seen from Figure 3, the thrust surface 42 and the running surface 31 are designed in the form of a spherical segment.

[0041] In an unloaded state, the convex running surface 31 and the concave contact surface 42 are arranged at least almost centrally to one another.

[0042] If radial forces from the gear unit 20 cause the output shaft 24 to deflect radially, the shaft end 30 shifts from the center of the thrust washer 36 and its concave thrust surface 42. This lateral displacement of the shaft end 30 leads to compression, i.e., elastic deformation of the elastomer element 34, which creates a force on the shaft end 30 that counteracts the deflection and re-centers the shaft end 30 in the thrust surface 42. In other words, a counterforce proportional to the deflection or bending of the output shaft 24 is generated, which counterforce reduces the deflection itself without overly supporting the output shaft 24 radially.

[0043] To facilitate the installation of the thrust washer 36 and avoid assembly errors, the thrust surface 42 is additionally formed on the second end face 40 facing away from the output shaft 24. This eliminates incorrect installation according to the Poka Yoke principle.

[0044] For radial support of the thrust washer 36, a central, disk-shaped projection 44 is provided at least on the second end face 40 of the thrust washer 36 facing the elastomer element 34, with the recess 46 of the elastomer element 34 having a complementary shape. Advantageously, the first end face 38 also has the central projection 44 according to the Poka Yoke principle.

[0045] The elastomer element 34 is arranged in a recess 48 of the housing 16. The recess 48 can be formed by a housing body 50 and a housing cover 52 attached to the housing body 50.

[0046] As can be seen from Figure 3, the elastomer element 34 has a cross-section that decreases toward the housing 16, so that a helix angle a is created on an outer side 54 of the elastomer element 34. The helix angle a is provided, for example, on all side surfaces 55, 57 of the elastomer element 34. As can be seen in particular from Figure 4, which shows an exploded view of the axial bearing 32, the helix angle a can also be formed only in a partial area of ​​the side surfaces 55, 57.

[0047] Furthermore, Figure 3 shows that the elastomer element 34 has, on an end face 56 with which it rests against the housing 16, an uneven structure with groove-like recesses 60 with a circular segment shape in cross-section, into which the material surrounding the recesses 60 is elastically deformable upon compression of the elastomer element 34. The material surrounding the recesses 60 forms tooth-like protrusions 58, which can deflect into the spaces formed by the recesses 60.

[0048] Within the scope of the invention, other structures forming free spaces are conceivable.

[0049] The shape and material of the elastomer element 34 determine its force-displacement characteristic curve. This is advantageously progressive, resulting in a non-constant spring constant of the elastomer element 34. In order to achieve a low preload force and thus low friction with low compression of the elastomer element 34, the shape of the elastomer element 34 is designed such that a very flat first characteristic curve region results. This can be achieved by the helix angle α, since the elastomer element 34 initially rests with its outer side 54 against the bounding side surfaces of the housing 16 upon compression.

[0050] Upon further compression, the elastomer element 34 deforms such that the tooth-like protrusions 58 can move into the spaces formed by the depressions 60. As soon as the spaces are filled, the characteristic curve of the elastomer element rises sharply, and a transition to an ideally stiff, second characteristic curve range of the elastomer element occurs.

[0051] The described axial bearing 32 is described according to the above-described embodiment for an adjusting device 10 used for a vehicle part. However, the invention is by no means limited to adjusting devices for vehicles.

[0052] It can also be used generally for actuators for other applications such as home automation, etc.

Claims

Claims 1. Actuating device (10) for a higher-level, i.e. not belonging to the actuating device (10), movable assembly, in particular for a vehicle part movable relative to a body of a vehicle, at least comprising a drive arrangement (12) with a drive unit (14), a gear unit (20) arranged in a housing (16) and an actuating element (22) which is displaceable relative to the drive arrangement (12) by means of the drive unit (14), wherein the drive unit (14) has an output shaft (24) which is mounted in the housing (16) at least by means of an axial bearing (32) for play and / or tolerance compensation, wherein a curved shaft end (30) of the output shaft (24) bears with a convex running surface (31) against a thrust washer (36) which is supported on an elastomer element (34) arranged in the housing (16), wherein the thrust washer (36) for bearing the curved shaft end (30) of the output shaft (24) has, on at least the end face (38) facing the output shaft (24), a concave contact surface (42) complementary to the convex running surface (31) of the shaft end (30).

2. Adjusting device (10) according to claim 1, characterized in that the convex running surface (31 ) of the shaft end (30) is arranged in the unloaded state at least almost centrally to the concave contact surface (42) of the contact disk (36).

3. Adjusting device (10) according to claim 2, characterized in that the contact surface (42) of the contact disk (36) and the running surface (31) of the shaft end (30) are designed to be complementary to one another in such a way that, in the case of a radial Deflection of the shaft end (30) from a center of the concave contact surface (42) by an elastic deformation of the elastomer element (34) a force counteracting the deflection can be generated on the shaft end (30).

4. Adjusting device (10) according to one of the preceding claims, characterized in that the elastomer element (34) has a progressive force-displacement characteristic curve.

5. Adjusting device (10) according to one of the preceding claims, characterized in that the elastomer element (34) has a cross-section that decreases in the direction of the housing (16).

6. Adjusting device (10) according to claim 4 or 5, characterized in that the elastomer element (34) has, on an end face (56) facing the housing (16), an uneven structure with depressions (60) into which the material surrounding the depressions (60) is elastically deformable upon compression of the elastomer element (34).

7. Adjusting device (10) according to one of the preceding claims, characterized in that the thrust washer (36) is arranged in a recess (46) of the elastomer element (34).

8. Adjusting device (10) according to one of the preceding claims, characterized in that at least the end face (40) of the thrust washer (36) facing the elastomer element (34) has a central projection (44) for radial support on the recess (46) of the elastomer element (34) complementary to the projection (44).

9. Adjusting device (10) according to one of the preceding claims, characterized in that the thrust washer (36) has a concave thrust surface (42) on each of its two end faces (38, 40).

10. Adjusting device (10) according to claim 8 and 9, characterized in that the thrust washer (36) has a central projection (44) on both end faces (38, 40).

11. Actuating device (10) according to one of the preceding claims, characterized in that the drive arrangement (12) is provided with a connecting unit (23) for connection to a higher-level assembly, i.e. one not belonging to the actuating device (10), while the actuating element (22) is provided with a further connecting unit for connecting the actuating element (22) to the higher-level assembly, i.e. one not belonging to the actuating device (10).

12. Adjusting device (10) according to one of the preceding claims, characterized in that the adjusting element (22) is provided as a spindle which can be displaced relative to the drive arrangement (12) by means of the drive unit (14).

13. Motor vehicle with a movable vehicle part as a higher-level assembly and with a body as a further higher-level assembly, characterized in that the movable vehicle part is equipped with an adjusting device (10) according to one of the preceding claims.

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