Drive, in particular spindle drive, for adjusting a closure element, in particular a flap, of a motor vehicle

Abstract

The invention relates to a drive, in particular a spindle drive (4), for adjusting a closure element (2), in particular a flap, of a motor vehicle (3), wherein the drive (1) has a drive motor (6) with a motor shaft (7) and a feed gear (9) for generating, in particular linear, drive movements for adjusting the closure element (2) between an open position and a closed position, wherein the drive (1) has a drive train (19) which runs from the drive motor (6) via an intermediate gear (8) connected downstream of the drive motor (6) to the feed gear (9), and wherein the drive (1) has a wrap spring brake (12) with a wrap spring (14), wherein the wrap spring brake (12) is designed to brake a rotation of a shaft (13) transmitting a torque between the drive motor (6) and the intermediate gear (8).It is proposed that the drive train (19) has a further shaft (20) which is connected in a rotationally fixed manner to the motor shaft (7) and that a braking torque generated by the wrap spring (14) is introduced into the drive train (19) via the further shaft (20).

Description

[0001] The present invention relates to a drive, in particular a spindle drive, for adjusting a closure element, in particular a flap, of a motor vehicle, according to the preamble of claim 1 and to a closure element arrangement of a motor vehicle according to claim 5.

[0002] The known prior art (DE 20 2008 016 929 U1), from which the invention is based, relates to a drive for adjusting a closure element in the form of a tailgate of a motor vehicle. This drive comprises a drive motor with a motor shaft and an intermediate gear connected downstream of the drive motor, which in turn is connected downstream of a feed gear. The known drive also comprises a wrap spring brake with a wrap spring. The wrap spring brake is designed to brake the rotation of a shaft transmitting torque between the drive motor and the intermediate gear.

[0003] It is a challenge that the wrap spring brake of the known drive acts on the motor shaft, which cannot be adapted to the wrap spring brake in terms of its properties to achieve the desired braking effect, or can only be adapted with great effort.

[0004] The invention is based on the problem of designing and developing the known drive in such a way that further optimization is achieved with regard to the aforementioned challenge.

[0005] The above problem is solved by the features of the characterising part of claim 1.

[0006] The fundamental consideration is that the wrap spring brake does not act directly on the motor shaft, but on another shaft that is connected to the motor shaft in a rotationally fixed manner, which can be easily manufactured with optimized properties such as surface roughness or elasticity for a desired braking effect.

[0007] In detail, it is proposed that the drive train has an additional shaft that is connected to the motor shaft in a rotationally fixed manner and that a braking torque generated by the wrap spring is introduced into the drive train via the additional shaft.

[0008] Claim 2 relates to a preferred embodiment of the shaft as an intermediate gear input shaft.

[0009] Claim 3 relates to a particularly preferred embodiment of the drive with a wrap spring brake arranged in an intermediate gear housing of the intermediate gear. Such a drive has the advantage that particularly little installation space is required for the wrap spring brake in the drive.

[0010] Claim 4 concerns the feed gear and specifies this as a spindle-spindle-nut gear. With such a spindle-spindle-nut gear, a locking element can be positioned very precisely relative to the vehicle body when installed. Furthermore, such a spindle-spindle-nut gear can be used to hold particularly heavy locking elements.

[0011] According to a further teaching according to claim 5, which has independent significance, a closure element arrangement of a motor vehicle with a proposed drive and a closure element, in particular a flap, is claimed.

[0012] Reference may be made to all statements regarding the proposed drive.

[0013] In the following, the invention is explained in more detail with reference to a drawing which merely represents exemplary embodiments. In the drawing, Fig. 1 a) the rear area of ​​a motor vehicle with a proposed drive for the closure element arrangement there and b) the proposed drive according to Fig. 1a) in a sectional side view in a retracted position and Fig. 2 a) an enlarged view of the Fig. 1 shown drive in the area of ​​a drive motor and b) an enlarged view of a detail of the proposed drive during assembly.

[0014] The embodiment shown in the figures and preferred in this respect relates to a drive 1 for adjusting a closure element 2 of a motor vehicle 3. Preferably, the drive 1, as shown in the figures, is designed as a spindle drive 4. As in Fig. 1a), the closure element 2 is preferably a tailgate 5 of a motor vehicle 3. Here, and preferably, only a single drive 1 is assigned to the tailgate 5. In principle, however, in addition to the drive 1, the tailgate 5 can also be assigned a further adjustment arrangement, in particular a motorless adjustment arrangement, wherein the adjustment arrangement and the drive 1 each act on opposite sides of the tailgate 5.

[0015] The term "closure element" is to be understood broadly. Such closure elements 2 include tailgates, trunk lids, hoods, doors, in particular side doors, cargo compartment floors, or the like of a motor vehicle 3.

[0016] The drive 1 further comprises a Fig. 1b) and Fig. 2a) with a motor shaft 7 and an intermediate gear 8 connected downstream of the drive motor 6, which is preferably designed as a reduction gear. The drive motor 6 is preferably an electric motor.

[0017] As in Fig. 1b) and Fig. 2, a feed gear 9 is connected downstream of the intermediate gear 8 in terms of drive technology. The feed gear 9 serves to generate linear drive movements between a first drive connection 10 of the drive 1 on the closure element side, i.e. a connection for coupling the drive 1 to the closure element 2, and a second drive connection 11 of the drive 1 on the body side, i.e. a connection for coupling the drive 1 to a body of the motor vehicle 3. The first drive connection 10 and the second drive connection 11 are linearly movable relative to one another along a geometric drive axis X and can be displaced axially relative to one another along the geometric drive axis X by actuating the drive motor 6.

[0018] The drive 1 further comprises a wrap spring brake 12 which is arranged between the drive motor 6 and the intermediate gear 8 and is designed to brake a rotation of a shaft 13 transmitting a torque between the drive motor 6 and the intermediate gear 8.

[0019] As in Fig. As shown in Figure 2, the wrap spring brake 12 has a wrap spring 14 formed by a wire 15 that extends in several turns around the shaft 13. The wire 15 has a radial wire contact surface (not shown) relative to its wire axis, and the shaft 13 has a radial shaft contact surface (not shown), wherein the wire contact surface can be brought into force-locking engagement with the shaft contact surface to generate a braking effect.

[0020] Here and as in Fig. 2a), the wrap spring brake 12 can be a wrap spring brake 12 that permanently brakes the shaft 13, in which the wire contact surface is permanently in frictional engagement with the shaft contact surface in the assembled state, in particular with a constant braking force. In principle, according to an embodiment not shown here, it can be a switchable wrap spring brake 12, in which the wire contact surface is or can be brought into frictional engagement with the shaft contact surface via a switching mechanism in the assembled state. For example, the switching mechanism can be configured to bring the wire contact surface into frictional engagement with the shaft contact surface when the first drive connection 10 and the second drive connection 11 are displaced relative to one another by an external force.

[0021] One of the drive connections 10, 11, here and preferably the first drive connection 10, is assigned to the drive motor 6, i.e. is axially fixed thereto.

[0022] The rotation of the shaft 13 can result from an operating drive motor 6. Accordingly, the wrap spring brake 12 can be used to brake a rotation of the shaft 13 due to an operating drive motor 6.

[0023] Because both the intermediate gear 8 and the feed gear 9 are connected downstream of the drive motor 6, the rotation of the shaft 13 can result from a relative axial displacement of the first drive connection 10 to the second drive connection 11 along the geometric drive axis X by introducing an external force into the two drive connections 10, 11. Accordingly, the wrap spring brake 12 can reduce or completely prevent the relative axial displacement of the first drive connection 10 to the second drive connection 11 when an external force is introduced into the two drive connections 10, 11.

[0024] The drive 1 here and preferably comprises a drive housing 16 with at least one first housing part 17 that is axially fixed to the drive connection 10 assigned to the drive motor 6. This first housing part 17 is rotationally fixed to the drive motor 6. Here and preferably, the wrap spring 14 is held rotationally fixed relative to the first housing part 17. Furthermore, here and preferably, the drive housing 16 also comprises a second housing part 18 that is axially fixed to the other drive connection 11 and is telescopic with the first housing part 17.

[0025] The exemplary embodiment shown in the figures and which is preferred in this respect relates to a drive 1, in particular a spindle drive 4, for adjusting a closure element 2, in particular a flap, of a motor vehicle 3, wherein the drive 1 has a drive motor 6 with a motor shaft 7 and a feed gear 9 for generating, in particular linear, drive movements for adjusting the closure element 2 between an open position and a closed position, wherein the drive 1 has a drive train 19 which runs from the drive motor 6 via an intermediate gear 8 connected downstream of the drive motor 6 to the feed gear 9, and wherein the drive 1 has a wrap spring brake 12 with a wrap spring 14, wherein the wrap spring brake 12 is designed to brake a rotation of a shaft 13 which transmits a torque between the drive motor 6 and the intermediate gear 8.

[0026] It is now essential that the drive train 19 has a further shaft 20 which is connected in a rotationally fixed manner to the motor shaft 7 and that a braking torque generated by the wrap spring 14 is introduced into the drive train 19 via the further shaft 20.

[0027] An “additional” shaft 20 means that the motor shaft 7 and the separate shaft 13 are separate components, i.e. they are manufactured separately from one another, and are only connected to one another in a rotationally fixed manner during the assembly of the drive 1.

[0028] The expression “introduced into the drive train 19 via the additional shaft 20” encompasses a direct and an indirect introduction of the braking torque into the additional shaft 20. In the case of a “direct” introduction of the braking torque, the wrap spring 14 acts directly on the additional shaft 20. In the case of an “indirect” introduction of the braking torque, a braking load, in particular a braking force or a braking torque, is transmitted from the wrap spring 14 to the additional shaft 20 via a transmission element (not shown here) assigned to the shaft 13 or the wrap spring 14. The transmission element, which is formed separately from the motor shaft 7, is either “assigned to the shaft 13”, i.e. is mounted on it and in particular is rotationally fixed thereto, or “assigned to the wrap spring 14”, i.e. is mounted on it and in particular is rotationally fixed thereto.

[0029] The additional shaft 20 can be connected to the motor shaft 7 in a form-fitting, rotationally fixed manner. For this purpose, the motor shaft 7 can, for example, have a projection that engages a corresponding recess on the additional shaft 20. However, this can also be provided the other way around. The additional shaft 20 can also be connected to the motor shaft 7 in a materially bonded manner, for example, by adhesive bonding, or frictionally bonded, for example, by means of a press fit.

[0030] Here, and preferably, the further shaft 20 is an intermediate gear input shaft 21. The intermediate gear 8 is here, and preferably, a planetary gear, which, in a known manner, comprises a sun gear, a planetary gear carrier with planetary gears, and a ring gear. In this regard, it is preferred that the intermediate gear input shaft 21 is, or can be, in frictional engagement with the sun gear of the planetary gear in the assembled state. In another embodiment, the intermediate gear 8 can also be a spur gear or a worm gear with a worm and worm gear.

[0031] As in Fig. 2b), it is preferred that the intermediate gear input shaft 21 is already connected to the motor shaft 7 in a non-assembled state in a rotationally fixed manner, and the intermediate gear input shaft 21 and the drive motor 6 form a pre-assembled drive unit 22. Subsequently, the wrap spring 14 can be pushed onto the intermediate gear input shaft 21 of the drive unit 22 in a first assembly step. As shown in Fig. 2b), the drive unit 22 with the wrap spring brake 12 can be connected to the intermediate gear 8 in a second assembly step in such a way that the intermediate gear input shaft 21 is in drive engagement with the intermediate gear 8.

[0032] Here, and preferably, it is provided that the intermediate gear 8 has an intermediate gear housing 23 and that the wrap spring brake 12 is arranged in the intermediate gear housing 23 in the assembled state. The intermediate gear housing 23 is designed here as a separate housing part from the first housing part 17, but can also be formed by it. As in Fig.2b), it is particularly preferred that the wrap spring brake 12 be recessed into the intermediate gear housing 23 during the assembly of the preassembled drive unit 22 with wrap spring brake 12 and intermediate gear 8, thereby saving a particularly large amount of installation space. This demonstrates how the use of a wrap spring brake 12 can advantageously utilize unused installation space, in this case unused installation space in the intermediate gear housing 23, so that a particularly compact drive 1 can be provided. Here and preferably, the wrap spring 14 is held in a rotationally fixed manner relative to the intermediate gear housing 23.

[0033] While the drive motor 6, the wrap spring brake 12, and the intermediate gear 8 were discussed above, a particularly preferred feed gear 9 will be discussed below. Here, and preferably, the feed gear 9 is a spindle-spindle nut gear 24 with a spindle 25 and a spindle nut 26 meshing with the spindle 25. A torque can be transmitted from the intermediate gear 8 to the spindle 25, the resulting rotation of which causes the spindle nut 26 to execute a linear movement along the geometric drive axis X and thus effect the relative displacement of the first drive connection 10 to the second drive connection 11.

[0034] A closure element arrangement of a motor vehicle 3 is proposed, comprising a proposed drive 1 and a closure element 2, in particular a flap.

[0035] Reference may be made to all statements relating to the proposed drive 1. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 20 2008 016 929 U1

[0002]

Claims

[1] Drive, in particular a spindle drive (4), for adjusting a closure element (2), in particular a flap, of a motor vehicle (3), wherein the drive (1) comprises a drive motor (6) with a motor shaft (7) and a feed gear (9) for generating, in particular linear, drive movements for adjusting the closure element (2) between an open position and a closed position, wherein the drive (1) comprises a drive train (19) which runs from the drive motor (6) via an intermediate gear (8) connected downstream of the drive motor (6) to the feed gear (9), and wherein the drive (1) comprises a wrap spring brake (12) with a wrap spring (14), wherein the wrap spring brake (12) is designed to brake a rotation of a shaft (13) transmitting a torque between the drive motor (6) and the intermediate gear (8), characterized bythat the drive train (19) has a further shaft (20) which is connected in a rotationally fixed manner to the motor shaft (7) and that a braking torque generated by the wrap spring (14) is introduced into the drive train (19) via the further shaft (20). [2] Drive according to claim 1, characterized by that the further shaft (20) is an intermediate gear input shaft (21), preferably that the intermediate gear (8) is designed as a planetary gear with a sun gear, a planet gear carrier with planet gears and a ring gear, further preferably that the intermediate gear input shaft (21) is in non-positive engagement with the sun gear of the planetary gear in the assembled state, or can be brought into non-positive engagement. [3] Drive according to claim 1 or 2, characterized by that the intermediate gear (8) has an intermediate gear housing (23) and that the wrap spring brake (12) is arranged in the intermediate gear housing (23). [4] Drive according to one of the preceding claims, characterized by that the feed gear (9) is a spindle-spindle nut gear (24) with a spindle (25) and a spindle nut (26) meshing with the spindle (25). [5] Closure element arrangement of a motor vehicle (3) with a drive (1) according to one of the preceding claims and a closure element (2), in particular a flap.

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