Spindle drive

Abstract

The present invention relates to a spindle drive (10) comprising a drive unit (12), a spindle (34), a housing unit (20) fixedly coupled to the drive unit (12), a bearing cage (28) received within the housing unit (20) and pivotable about a pivot axis by a predetermined angular range, and a spindle nut (30) mounted in the bearing cage (28) in an angularly fixed manner and which engages in threads with the spindle (34), wherein the spindle nut (30) can be driven into rotation by the drive unit (12) via a transmission arrangement (18).

Description

[0001] The present invention relates to a spindle drive with a drive unit, a spindle and a spindle nut engaged in threaded engagement with the spindle, as well as a door arrangement for a vehicle which includes such a spindle drive.

[0002] A typical application for spindle drives, which are generally used in various fields to move one element relative to another, is the operation of vehicle doors or hatches. Such automatic operation of doors and hatches, especially tailgates, requires a spindle drive design capable of handling the pivoting movements of these elements relative to the vehicle body. This has sometimes involved the use of quite complex spindle drives mounted on the vehicle door or hatch on one side and on the vehicle body on the other, in order to follow all movements of the hatch or door. However, such elaborate spindle drive mountings require considerable installation space and can be costly and maintenance-intensive.

[0003] Although the following discussion will mainly focus on the possible application in a vehicle, it is understood that corresponding spindle drives can also be used in various other fields and scenarios where comparable kinematics are required.

[0004] In the prior art, for example, DE 10 2017 204 914 A1 discloses a spindle drive in which a spindle is driven, and a connecting element, which is pivotably mounted on a spindle nut engaged in threaded engagement with the spindle, is designed, for example, to connect to a flap. However, the device described therein has the disadvantage that it requires an additional and relatively complex connecting element between the spindle nut and the element to be driven, which increases its installation space.

[0005] Furthermore, reference should be made to DE 10 2018 212 959 A1, which teaches a spindle drive in which the corresponding spindle nut is gimbal-mounted on a drive element. A similar approach was pursued in US 10 655 378 B2, in which a spindle nut is also mounted in a complex manner relative to a drive unit in order to create degrees of freedom between the drive unit and the spindle.

[0006] However, all of the aforementioned prior art solutions require a relatively large number of components and are therefore costly and require significant maintenance. The object of the present invention is thus to provide a spindle drive which, with a simplified design, enables a pivoting movement of its spindle relative to its drive unit and consequently requires less installation space and is more cost-effective.

[0007] To solve this problem and to eliminate the disadvantages of the prior art described above, a spindle drive is proposed according to the invention, comprising a drive unit, a spindle, a housing unit rigidly coupled to the drive unit, a bearing cage received within the housing unit and pivotable about a pivot axis by a predetermined angular range, and a spindle nut mounted in the bearing cage in an angle-fixed manner, which is in thread engagement with the spindle, wherein the spindle nut can be driven into rotation by the drive unit via a transmission arrangement.

[0008] Accordingly, in the spindle drive proposed according to the invention, the pivotability of the spindle relative to the drive unit is achieved by receiving the spindle nut associated with the spindle in a bearing cage that can pivot relative to a housing, the housing unit being rigidly coupled to the drive unit. Consequently, pivoting the bearing cage relative to the housing unit results in pivoting the spindle relative to the drive unit, thus eliminating the need for complex joint or cardan arrangements. Moreover, the present invention makes it possible to separate a kinematically predetermined pivoting movement of a spindle from the drive itself, since the joint enabling the pivoting movement is arranged between the spindle and the drive.

[0009] For the mounting of the spindle nut in the bearing cage, a deep groove ball bearing can preferably be provided, which is particularly suitable for this purpose in that it can absorb all acting forces in a suitable manner.

[0010] Furthermore, according to the invention, the transmission arrangement between the spindle nut and the drive unit can be formed by a worm gear with a worm shaft and a worm wheel, wherein the worm shaft can be coupled to the drive unit and the worm wheel can be coupled to the spindle nut. In particular, the worm wheel can be integrally formed with the spindle nut by means of a toothing on its radial outer surface, so that the worm nut can be directly subjected to drive torques from the transmission arrangement via the worm shaft without any further intermediate components. This design directly contributes to reducing the number of necessary components and saving installation space in the area of ​​the spindle drive.

[0011] Furthermore, in such a design, the pivot axis of the bearing cage can coincide with the extension direction of the worm shaft, provided that no additional components are provided between the worm shaft and the spindle nut at this point.

[0012] Furthermore, it is advantageous to completely enclose the transmission arrangement within the housing unit, as this protects the components forming the transmission arrangement from the ingress of dirt and damage without requiring additional installation space for a corresponding cover.

[0013] For a similar purpose, the housing unit can be closed off on its side facing away from the drive unit by a housing cover, which also helps to protect the spindle nut, the bearing cage and, if applicable, other components contained within the housing unit from external influences.

[0014] Furthermore, the pivot plane of the spindle can be perpendicular to a longitudinal direction of the drive unit. Particularly in the embodiment described above, where the worm gear is integrally formed with the spindle nut, the worm shaft can be formed directly as an extension of a motor shaft of the drive unit or integrally with it, thus also running along the longitudinal direction of the drive unit. Of course, embodiments are also conceivable in which the drive unit is positioned at an angle to the pivot plane of the spindle, provided that a suitable gearbox or a deflection device for the drive rotation with an angular offset is interposed.

[0015] To define the angular range of the bearing cage's pivoting motion within the housing unit, the housing unit can, in particular, include an inner profile in the form of an arc segment along which the bearing cage's outer profile runs within the housing unit. Thus, in such a configuration, the bearing cage has an outer shape that corresponds to this inner profile of the housing unit, thereby enabling pivoting between the respective end positions of the arc segment. Alternatively, other means for defining and limiting the pivoting motion of the bearing cage within the housing unit could, of course, be provided, in particular stops and similar devices that limit the bearing cage's range of motion.

[0016] Regarding the design of the bearing cage, it can, for example, be constructed in two parts, with the two parts being connectable in a state in which the spindle nut and, if applicable, the aforementioned bearing are inserted. The connection between the two parts can be either detachable and indirect, for example by clips or screws, or direct and permanent, for example by laser or ultrasonic welding.

[0017] In order to mount the spindle drive according to the invention to a higher-level structure for relative movement of two components thereof, the spindle and the drive unit can each be provided with connection arrangements for mounting the spindle drive to this higher-level assembly. These can be, among other things, simple hinge arrangements which themselves in turn allow the spindle drive to pivot about a respective hinge axis.

[0018] Furthermore, a free end of the spindle, for example the end opposite the aforementioned connection arrangement, can be received in a funnel-shaped housing element, which on the one hand enables the pivoting movement of the spindle and on the other hand protects it against external access and thus against contamination and the like.

[0019] Furthermore, it should be noted that the drive unit of the spindle drive according to the invention will generally be formed by an electric motor with a rotating motor shaft in a design known per se and may optionally include a gearbox, in particular a planetary gearbox, and / or a braking device, in particular a friction brake.

[0020] As already indicated above, the present invention further relates to a door or flap arrangement for a vehicle, comprising a vehicle door or flap pivotally mounted on a vehicle body about a hinge axis, and a spindle drive of the type just described arranged between the vehicle body and the vehicle door or flap. The longitudinal direction of the drive unit, defined, for example, by its motor shaft, can be parallel to the hinge axis of the vehicle door, which allows for a particularly space-saving installation.

[0021] Further features and advantages of the present invention will become even clearer from the following description of an embodiment thereof, when viewed together with the accompanying figures. These show in detail: Fig. 1A and Fig. 1B an exploded view of a spindle drive according to the invention and an enlarged section thereof; Fig. 2A to 2C Sectional views of the spindle drive from the Fig. 1A and Fig. 1B along the pivot plane of its spindle in three different pivot states; and Fig. 3 a side view of the spindle drive from the Fig. 1A to 2C in assembled state.

[0022] In the Fig. Figures 1A to 3 show a spindle drive according to the invention in different views and are generally designated by reference numeral 10. This spindle drive 10 can, for example, form part of a door or flap assembly for a vehicle not shown, in which it is arranged between a vehicle door or flap and a vehicle body of the vehicle in question.

[0023] The spindle drive 10 comprises, firstly, a drive unit 12 in the form of an electric motor with a motor shaft 14, whereby the drive unit may include further components, for example, a gearbox (not shown) or a brake. Furthermore, it should be noted that the drive unit 12 is associated with a connection arrangement 12a, with which the spindle drive 10 can be attached to a higher-level assembly, in particular the vehicle body or the vehicle door or vehicle flap in the aforementioned specific application of use in a vehicle.

[0024] Furthermore, especially in Fig. 1A shows that a worm shaft 16 is mounted directly on the motor shaft 14 in a rotationally fixed manner, which forms part of a transmission arrangement 18 described further below, which is particularly important in the Fig. 2A to 2C are clearly visible. As also shown in the Fig. As can be seen best in 2A to 2C, the motor shaft 14 with its attached worm shaft 16 extends into a housing unit 20, which in an assembled state of the Fig. 1A The spindle drive 10 shown in exploded view is firmly connected to the drive unit 12, for example by screwing it on.

[0025] This housing unit 20 can in turn be screwed to a top housing cover 22 and a side housing cover 24, which secure the housing unit 20 at its top and in the Fig. 2A to 2C on the right-hand side. Furthermore, a funnel-shaped shell element 26 is provided on the side of the housing unit 20 opposite the side housing cover 24. This element protects the spindle 34 described below from external influences in this area and simultaneously allows it to pivot relative to the housing unit 20.

[0026] Furthermore, it should be noted that the housing unit 20 has an interior with an internal profile 20a, which is formed in the form of an arc section and is located both in the Fig. 1A as well as 2A to 2C are clearly visible. A bearing cage 28 is now inserted into this inner profile 20a, which is formed in two parts: a first and a second cage part 28a and 28b, which are connected to each other either permanently or detachably in an assembled state.

[0027] This bearing cage 28 is designed with respect to its outer contour such that it can pivot within the inner profile 20a of the housing unit 20 by a predetermined angle about an axis which corresponds to the direction of extension of the motor shaft 14, wherein this pivot angle in the embodiment shown here is by way of example about ± 12 degrees.

[0028] Within the bearing cage 28, a spindle nut 30, together with a deep groove ball bearing 32, is mounted such that it is rotatable relative to the bearing cage 28 but fixed in the axial direction. It can also be seen that the spindle nut 30 has a toothed section 30a on its outer surface, which acts as a worm gear for the worm shaft 16 on the motor shaft 14 of the drive unit 12. Accordingly, operation of the motor of the drive unit 12, and thus rotation of the worm shaft 16, directly causes rotation of the spindle nut 30 within the bearing cage 28. This rotation of the spindle nut 30 is possible in all pivot positions of the bearing cage 28 relative to the housing unit 20.

[0029] This is particularly true in the Fig. Figures 2A to 2C indicate which end positions of the pivoting movement of the bearing cage 28 within the housing unit 20, as well as a neutral position. It can also be seen that the three states are derived from the Fig. 2A to 2C each correspond to a different stroke state of a spindle 34, which is guided within the spindle nut 30 and is in thread engagement via a cooperating thread pair 36.

[0030] Accordingly, the in the Fig. The pivoting movement shown in 2A to 2C is compensated for by a kinematics defined by the two higher-level components and their connection, which is achieved on the one hand via the aforementioned connection arrangement 12a on the drive unit 12 and on the other hand via a second connection arrangement 34a on the [unclear] Fig. 2A to 2C are coupled to the right-hand end of spindle 34.

[0031] Finally, it should be noted that the spindle drive 10 also comprises a flexible sleeve element 38, by means of which the spindle 34 is extended from the housing unit 20 to the Fig. 2A to 2C is led out on the side shown on the right, and which also prevents the ingress of contaminants or similar substances into the housing unit 20 at this point.

[0032] Accordingly, the spindle drive 10 shown here according to the invention allows the spindle 34 to be pivoted relative to the drive unit 12 in a simple and compact manner, and thus a pivot path curve defined by a kinematics of external components, which is directly related to the current stroke position of the spindle 34. QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] DE 10 2017 204 914 A1

[0004] DE 10 2018 212 959 A1

[0005] US 10 655 378 B2

[0005]

Claims

[1] Spindle drive (10), comprising: - a drive unit (12); - a spindle (34); - a housing unit (20) permanently coupled to the drive unit (12); - a bearing cage (28) accommodated within the housing unit (20) and pivotable about a pivot axis through a predetermined angular range; and - a spindle nut (30) mounted in the bearing cage (28) in an angle-fixed manner, which engages in threaded engagement with the spindle (34), wherein the spindle nut (30) can be driven into rotation by the drive unit (12) via a transmission arrangement (18). [2] Spindle drive (10) according to claim 1, wherein a deep groove ball bearing (32) is provided for the bearing of the spindle nut (30) in the bearing cage (28). [3] Spindle drive (10) according to one of the preceding claims, wherein the transmission arrangement (18) is formed by a worm gear with a worm shaft (16) and a worm wheel (30a), wherein the worm shaft (16) is coupled to the drive unit (12) and the worm wheel (30a) is coupled to the spindle nut (30). [4] Spindle drive (10) according to claim 3, wherein the worm gear (30a) is integrally formed with the spindle nut (30) by means of a toothing on its radial outer side. [5] Spindle drive (10) according to claim 3 or 4, wherein the pivot axis of the bearing cage (28) coincides with the extension direction of the worm shaft (16). [6] Spindle drive (10) according to one of claims 3 to 5, wherein the direction of extension of the worm shaft (16) coincides with a longitudinal direction of the drive unit (12). [7] Spindle drive (10) according to one of the preceding claims, wherein the transmission arrangement (18) is completely contained within the housing unit (20). [8] Spindle drive (10) according to one of the preceding claims, wherein the housing unit (20) is closed off on its side facing away from the drive unit (12) by a housing cover (22). [9] Spindle drive (10) according to one of the preceding claims, wherein the pivot plane of the spindle (34) is perpendicular to a longitudinal direction of the drive unit (12). [10] Spindle drive (10) according to one of the preceding claims, wherein the angular range of the pivotability of the bearing cage (28) within the housing unit (20) is defined by an inner profile (20a) of the housing unit (20) in the form of an arc segment along which the bearing cage (28) runs with its outer profile. [11] Spindle drive (10) according to one of the preceding claims, wherein the bearing cage (28) is constructed in two parts, wherein the two parts (28a, 28b) can be connected to each other in a state in which the spindle nut (30) is inserted therein. [12] Spindle drive (10) according to one of the preceding claims, wherein the spindle (34) and the drive unit (12) are each provided with connection arrangements (34a, 12a) for mounting the spindle drive (10) on a higher-level assembly. [13] Spindle drive (10) according to one of the preceding claims, wherein a free end of the spindle (32) is received in a funnel-shaped shell element (26). [14] Spindle drive (10) according to one of the preceding claims, wherein the drive unit (12) comprises a gearbox, in particular a planetary gearbox, and / or a braking device, in particular a friction brake. [15] Door or hatch arrangement for a vehicle, comprising: - a vehicle door or hatch that is pivotally attached to the vehicle body about a hinge axis; and - a spindle drive (10) arranged between the vehicle body and the vehicle door or vehicle flap according to one of the preceding claims. [16] Door or flap arrangement according to the preceding claim, wherein the longitudinal direction of the drive unit (12) is parallel to the hinge axis of the vehicle door.

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