Drive device for a closure element of a motor vehicle

Abstract

The invention relates to a drive device for a closure element (2) of a motor vehicle, wherein the drive device (1) has a drive train (10) having two drive sections each having a drive connection, wherein the drive sections can be moved linearly relative to one another along a geometric axis (7) between a retracted position and an extended position in order to generate linear drive movements between the drive connections, wherein an end stop (15) is provided in order to limit the drive movement between the drive connections to the extended position, wherein the end stop (15) has end stop surfaces on the drive sections which can be moved towards one another and a damping unit (16), which damps the drive movement as a function of its speed during a drive movement into the end stop (15), wherein the damping unit (16) has a damping element (17), which can be plastically deformed during the drive movement by means of an axial impact of the end stop surfaces on one another or on an intermediate element (18). It is proposed that the plastically deformable damping element (17) is an axially fixed, radially outwardly pointing projection (19), in particular a circumferential collar, of a drive train component (20) of one drive section.

Description

[0001] Drive device for a closure element of a motor vehicle

[0002] The present invention relates to a drive device for a closure element of a motor vehicle according to the preamble of claim 1. The known prior art (DE 10 2017 127 859 A1), from which the invention is based, relates to a drive device according to the preamble of claim 1.

[0003] The term "closure element" is to be understood broadly. Such closure elements include tailgates, trunk lids, hoods, doors, especially side doors, sliding doors, cargo floor, and the like of a motor vehicle.

[0004] The drive device in question has become increasingly important in recent years to offer the user a high degree of comfort. This is particularly true for large closure elements of a motor vehicle, whose weight makes manual opening or closing movements of the closure element difficult. In such a case, the drive device can take over the opening and / or closing process and also allows the closure element to be held in the open position or intermediate positions.

[0005] The known drive device is designed as a spindle drive. The spindle drive serves to adjust a closure element of a motor vehicle as defined above. For this purpose, the spindle drive is equipped with a drive motor and a spindle-spindle nut gear connected downstream of the drive motor to generate drive movements. To transmit the drive movements, the spindle drive has two drive sections, each with a drive connection. The drive connections are moved axially away from each other when the spindle drive is extended and axially towards each other when the spindle drive is retracted. A spring arrangement is integrated into the known drive device, which preloads the two mutually movable drive sections against each other into the extended position of the drive device. The spring arrangement provides considerable spring forces.In order to increase operational reliability, a damping device is provided in the known spindle drive between the end stop surfaces, which move towards one another during a movement into the extended position of the drive device. This dampens the drive movement during a drive movement to the end stop depending on the speed of the drive movement. The known damping device has a damping element in the form of a plastically deformable plastic bushing, wherein damping of an impact between the end stop surfaces is achieved by the damping element being axially loaded between the end stop surfaces, thereby deforming it and, in the deformed state, moving it towards the other end stop surface by one end stop surface. This other end stop surface is formed by a further plastic bushing.Both bushings, also called stop nuts, are axially fixed to the spindle during assembly. This makes the design of the drive device relatively complex.

[0006] It is a challenge to improve the known state of the art.

[0007] The invention is based on the problem of designing and developing the known drive device in such a way that further optimization is achieved with regard to the aforementioned challenge.

[0008] The above problem is solved by the features of the characterising part of claim 1.

[0009] The fundamental consideration is that the damping element is an axially fixed and, in particular, integral part of a strand component of one of the two drive sections. This eliminates the need to mount separate components on the strand component, such as a separate stop nut, to form the damping device. Preferably, the damping element is therefore not manufactured and assembled separately, but rather formed from a section of the strand component that is already formed during production, in particular during machining or turning, of the strand component. In this way, the damping device and thus the entire drive device is particularly simple in design and can be assembled accordingly.

[0010] It should be noted that the damping effect in question preferably does not occur during normal operation of the drive device, but only in the event of misuse, for example, if the user applies excessive opening forces when manually opening the closure element, or in the event of component failure, for example, if a drive connection of the drive device accidentally detaches from the closure element or the edge area of ​​the closure element opening. The plastic deformation of the damping element therefore only occurs in the special situations mentioned above to prevent major property damage or even personal injury.

[0011] In detail, it is proposed that the plastically deformable damping element is an axially fixed, radially outwardly facing projection, in particular a circumferential collar, of a strand component of one drive section.

[0012] Claim 2 defines a particularly preferred design of the drive device, in which the drive section having the damping element comprises a rod and the other drive section comprises a tube. Particularly preferably, the rod is the spindle of a spindle-spindle nut transmission, and preferably the tube is a spindle nut tube axially fixed to the spindle nut of the spindle-spindle nut transmission. Claim 3 specifies the radially outwardly facing projection, which is preferably part of a collar. The radially outwardly facing projection is then preferably formed by a groove introduced into the collar, whereby a plastically deformable damping element adapted to the respective requirement, in particular in terms of its thickness, can be provided in a simple manner.

[0013] Claim 4 defines particularly preferred materials and arrangements of the intermediate element and a guide element. Claim 5 specifies particularly preferred configurations and positions of the end stop surfaces, which, in said misuse situation, cause the plastic deformation of the damping element, possibly via the intermediate element. The invention is explained in more detail below with reference to a drawing that merely illustrates exemplary embodiments. In the drawing, Fig. 1 shows, in a very schematic representation, the rear area of ​​a motor vehicle with a tailgate equipped with a proposed drive device, and

[0014] Fig. 2 in a sectional side view of the device according to Fig. 1 a) in the retracted position during normal operation and b) in the extended position after use of a damping device of the device.

[0015] The drive device 1 shown in the drawing is designed as a spindle drive and serves for the motorized adjustment of a closure element 2 of a motor vehicle, designed here, for example, as a tailgate. For a further understanding of the term "closure element" 2, reference is made to the introductory part of the description. The invention is explained below using a closure element 2 designed as a tailgate, since, precisely in this case, a particularly high level of reliability of the drive device 1 is required due to the comparatively high forces caused by the weight of the closure element 2.

[0016] The spindle drive is equipped with a drive unit 3, preferably an electric one, which has an electric drive motor 4 and an intermediate gear 5 connected downstream of the drive motor 4. A feed gear, here a spindle-spindle nut gear 6, with a geometric gear axis 7 for generating linear drive movements between two drive connections 11, 12 is connected downstream of the drive unit 3. The spindle-spindle nut gear 6 has, in a conventional manner, a spindle 8 with an external spindle thread and a spindle nut 9 with an internal spindle thread, which form a screw engagement with one another.

[0017] The drive device 1 in the form of a spindle drive has a drive train 10 with two drive sections 10a, 10b, each drive section 10a, 10b having an associated drive connection 11, 12. The two drive sections 10a, 10b are driven by the spindle-spindle nut gear 6 and are movable linearly relative to one another. In the exemplary embodiment selected here, the spindle 8 is assigned to one, here upper, drive section 10a and thus to the first drive connection 11, whereas the spindle nut 9 is assigned to the other, here lower, drive section 10b and thus to the second drive connection 12. By actuating the drive unit 3, the spindle 8 is set in rotation and the spindle nut 9 is moved axially relative to the spindle 8. The spindle nut 9 is here and preferably axially fixedly connected to a spindle nut tube 13, wherein the spindle nut tube 13 is in turn connected to the second drive connection 12.In this way, the relative movement between spindle 8 and spindle nut 9 is transmitted via the spindle nut tube 13 to the second drive connection 12, whereby the drive connections 11, 12 move accordingly relative to one another. In the assembled state shown in Fig. 1, the spindle drive is drive-technically coupled to the closure element 2. In this case, the spindle drive takes over the adjustment of the closure element 2, here the tailgate, between the open position shown in Fig. 1 and a closed position not shown, in the manner described above. For the sake of completeness, it should be mentioned that the drive device 1, shown here as an example of a spindle drive, can also be operated manually, i.e. the user can also open and / or close the closure element 2 manually.In order to enable manual adjustment despite the optional drive unit 3 with drive motor 4, the drive device 1 can further comprise an overload clutch (not shown). It is also conceivable in principle to design a drive device 1 for purely manual operation and to dispense with a drive unit 3 as described above.

[0018] The drive device 1 or the spindle drive here and preferably also has a spring arrangement 14 which pretensions the two drive sections 10a, 10b against each other into the extended position and thus urges the closure element 2 into the open position. Here and preferably the spring arrangement 14 has a compression spring. In the exemplary embodiment shown in Fig. 1 and thus preferred, a total of two drive devices 1, here and preferably two spindle drives, are provided, which are arranged at two opposite edge regions of a closure element opening, in this case a tailgate opening. In principle, however, it can also be provided that only one such drive device 1 is provided, which is then arranged in particular at one of the edge regions of the closure element opening.The drive device 1 described here further comprises an end stop 15 to limit the drive movement between the drive connections 11, 12 to the extended position. The end stop 15 has a first end stop surface 15a and a second end stop surface 15b on each associated drive section 10a, 10b, which can be moved toward one another, as well as a damping device 16 that dampens the drive movement depending on its speed during a drive movement into the end stop 15. This results in a large impact force in the end stop 15, which is to be absorbed by the damping device 16 and absorbed as completely as possible.

[0019] A drive device 1 for a closure element 2 of a motor vehicle is claimed, wherein the drive device 1 has a drive train 10 with two drive sections 10a, 10b, each with a drive connection 11, 12, wherein the drive sections 10a, 10b are movable linearly relative to one another along a geometric axis 7 between a retracted position and an extended position in order to generate linear drive movements between the drive connections 11, 12, wherein an end stop 15 is provided in order to limit the drive movement between the drive connections 11, 12 to the extended position, wherein the end stop 15 has end stop surfaces 15a, 15b on the drive sections 10a, 10b that can be moved towards one another and a damping device 16 that dampens the drive movement depending on its speed during a drive movement into the end stop 15, wherein the damping device 16 comprises a damping element 17,which is plastically deformable during the drive movement by an axial impact of the end stop surfaces 15a, 15b on each other or on an intermediate element 18.

[0020] It is now essential that the plastically deformable damping element 17 is an axially fixed, radially outwardly facing projection 19, in particular a circumferential collar, of a strand component 20 of the one drive section 10a.

[0021] A strand component 20 is a component in the drive train 10 that serves to transmit the drive movements. The component itself therefore has the function of transmitting movement. The projection 19 follows the movements of the strand component 20 and is in particular machined out of the strand component 20, for example by machining. Furthermore, it is preferably provided here that the drive section 10a having the damping element 17 has a rod that forms the strand component 20, and the other drive section 10b has a tube, that the rod is in sliding and / or screwing engagement with the inside of the tube, and that the damping element 17 is an axially fixed component of the rod, preferably that the rod is the spindle 8 of a spindle-spindle nut gear 6, further preferably that the tube is a spindle nut tube 13 that is axially fixedly connected to the spindle nut 9 of the spindle-spindle nut gear 6.

[0022] As previously described, the drive device 1 is preferably designed as a spindle drive, i.e., it has a spindle-spindle nut gear 6 as a feed gear. However, it is also conceivable for the rod and tube to be threadless and, for example, to be part of a drive device 1 designed as a gas spring.

[0023] Furthermore, it is preferably provided here that the radially outward-pointing projection 19 is made of metal and / or is otherwise rotationally fixed to the strand component 20 and in particular is otherwise formed in one piece with the strand component 20, preferably that the radially outward-pointing projection 19 is part of a collar 21 for axially securing a stop disk or sleeve, which forms the intermediate element 18 between the end stop surfaces 15a, 15b, and / or a guide element 22 arranged axially outside the end stop 15, in particular a guide disk or sleeve, for axial guidance in the pipe, further preferably that the radially outward-pointing projection 19 is formed by a groove 23 introduced into the collar 21.

[0024] Here and preferably, the collar 21 serves to support the intermediate element 18 on one axial side, which in turn is axially secured on its other side by a section, in particular a threaded section, of the strand component 20, and to support the guide element 22 on the other axial side, which in turn is axially secured on its other side by a further support element. The guide element 22 is here and preferably arranged outside the end stop 15, thus outside the space between the end stop surfaces 15a, 15b. Furthermore, it is here and preferably provided that the intermediate element 18 is made of metal and / or is rotationally fixed to the strand component 20, and / or that the guide element 22 is made of plastic and / or is rotatable relative to the strand component 20.

[0025] Metal has the advantage of optimally transferring the force required to deform the projection 19 from one end stop surface 15b to the other end stop surface 15a. However, the intermediate element 18 can also be made of a different material, such as plastic. Plastic has the advantage of optimally sliding the guide element 22 within the tube. However, this guide element 22 can also be made of a different material, such as metal.

[0026] Furthermore, it is preferably provided here that the damping element 17 forms one of the end stop surfaces 15a, preferably that the other end stop surface 15b is formed on the inside of the tube and is formed in particular by at least one radially inwardly pointing projection 24, preferably that the projection 24 forms an axial end of the spindle nut 9 and / or is in contact with an axial end of the spindle nut 9.

[0027] The projection 24 can be produced by forming, for example by rolling or the like.

Claims

Patent claims 1. Drive device (1) for a locking element (2) of a motor vehicle, wherein the drive device (1) has a drive train (10) with two drive sections (10a, 10b) each with a drive connection (11, 12), wherein the drive sections (10a, 10b) are linearly movable relative to each other to generate linear drive movements between the drive connections (11, 12) along a geometric axis (7) between a retracted position and an extended position, wherein an end stop (15) is provided to limit the drive movement between the drive connections (11, 12) to the extended position, wherein the end stop (15) has end stop surfaces (15a, 15b) on the drive sections (10a, 10b) that can move towards each other and a damping device (16) which dampens the drive movement during a drive movement into the end stop (15) depending on its speed,wherein the damping device (16) has a damping element (17) which is plastically deformable during the drive movement by an axial impact of the end stop surfaces (15a, 15b) on each other or on an intermediate element (18), characterized in that the plastically deformable damping element (17) is an axially fixed, radially outwardly projecting projection (19), in particular a circumferential collar, of a strand component (20) of one drive section (10a).

2. Drive device (1) according to claim 1, characterized in that the drive section (10a) having the damping element (17) has a rod forming the string component (20), and the other drive section (10b) has a tube, that the rod is in sliding and / or screw engagement with the inside of the tube, and that the damping element (17) is an axially fixed component of the rod, preferably that the rod is the spindle (8) of a spindle-spindle nut drive (6), further preferably that the tube is a spindle nut tube (13) axially fixed to a spindle nut (9) of the spindle-spindle nut drive (6).

3. Drive device (1) according to claim 1 or 2, characterized in that the radially outwardly extending projection (19) is made of metal and / or is rotationally fixed to the strand component (20) in the rest and in particular is formed integrally with the strand component (20) in the rest, preferably that the radially outwardly extending projection (19) is part a collar (21) for axially securing a stop disc or sleeve, which forms the intermediate element (18) between the end stop surfaces (15a, 15b), and / or a guide element (22) arranged axially outside the end stop (15), in particular a guide disc or sleeve, for axial guidance in the tube, further preferably that the radially outwardly pointing projection (19) is formed by a groove (23) provided in the collar (21).

4. Drive device (1) according to one of the preceding claims, characterized in that the intermediate element (18) is made of metal and / or is rotationally fixed to the strand component (20), and / or that the guide element (22) is made of plastic and / or is rotatable to the strand component (20).

5. Drive device (1) according to one of the preceding claims, characterized in that the damping element (17) forms one of the end stop surfaces (15a), preferably that the other end stop surface (15b) is formed on the inside of the tube and is formed in particular by at least one radially inwardly pointing projection (24), preferably that the projection (24) forms an axial end of the spindle nut (9) and / or is in contact with an axial end of the spindle nut (9).

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