Spindle drive and comfort drive with a spindle drive

Abstract

Spindle drive (10), with a gear housing (15) connected to a drive motor (12), wherein the gear housing (15) has a housing base body (16; 16a) and at least one housing cover (18; 18a, 20; 20a) connected to the housing base body (16; 16a), wherein the housing base body (16; 16a) and the at least one housing cover (18; 18a, 20; 20a) delimit a receiving space (24) for a drive element (25) cooperating with the drive motor (12), wherein the drive element (25) is connected to a spindle (28) which penetrates the receiving space (24), wherein means (37), in particular in the form of a shaft ring, are provided for arranging the drive element (25) in the receiving space (24) without axial play, and wherein the means (37) are arranged in a receiving area (39) in the receiving space (24) are arranged, characterized in that at least one element (40; 40a) is provided which has a connection to the element (40;40a) and the housing base body (16) or the at least one housing cover (18a, 20a), which extends coaxially to the axis of rotation (32) of the spindle (28), enables adjustment of the size of the receiving area (39);

Description

State of the art

[0001] The invention relates to a spindle drive according to the preamble of claim 1. Furthermore, the invention relates to a comfort drive with a spindle drive according to the invention.

[0002] From DE 10 2016 203 639 A1, the applicant discloses a spindle drive having the features of the preamble of claim 1. The known spindle drive is characterized by a multi-part gear housing comprising a housing base body connectable to a drive motor and two housing covers. The housing base body has a through-opening for arranging a drive element in the form of a worm gear connected to a spindle. The through-opening is delimited by the housing covers that define the front side of the through-opening in order to form the receiving space for the drive element. Furthermore, for reasons of low noise during operation, in particular, such a spindle drive requires means that apply axial force to the drive element within the receiving space of the gear housing, such that the drive element is arranged within the receiving space without axial play.For this purpose, the known document provides for a wave spring or a wave ring to be arranged within the receiving space and radially enclose an extension or axle stub that protrudes axially from the drive element. Furthermore, two bearing elements in the form of thrust washers for the drive element or the worm gear are provided in the receiving space. These bearing elements are selected from predetermined thrust washer thicknesses depending on a measured axial play and, together with the wave spring, serve to adjust / prevent the axial play.

[0003] The two thrust washers represent additional components that must be considered when designing the spindle drive or the gearbox housing's mounting space. Furthermore, the thrust washers and their selection require additional measurement and assembly effort. Disclosure of the invention

[0004] The spindle drive according to the invention with the features of claim 1 has the advantage that the thrust washers provided in the prior art as additional, separate components can be dispensed with and, instead, at least one element is provided which is intended for adjusting a defined size of a receiving area, in particular for a shaft ring. In contrast to the thrust washers in the prior art, such an element according to the invention thus enables a structurally different design or configuration of the gear housing. Furthermore, the element represents a particularly precise and accurate element because it is continuously adjustable due to the provision of the threaded connection and an associated, individually provided screw-in depth.In particular, this also allows manufacturing tolerances of the relevant components to be expanded, since in practice a wider range of existing mounting areas can be adjusted using the element provided with the threaded connection compared to thrust washers.

[0005] Advantageous further developments of the spindle drive according to the invention are listed in the subclaims.

[0006] In order to arrange the threaded connection on the gear housing in such a way that it is as protected as possible against external mechanical influences, a preferred structural embodiment of the invention provides that the element has an external thread which interacts with an internal thread, wherein the internal thread is formed on a wall of the housing base body or a housing cover which delimits the receiving space.

[0007] In a preferred design development of the last proposal, the internal thread is formed on the housing base body over the entire height running in the direction of the rotational or longitudinal axis of the spindle, and two elements are provided that are arranged on opposite end faces of the housing base body. Such a design thus makes it possible to adjust the receiving area for the wave spring from opposite sides of the housing base body. Furthermore, it is possible, for example, to use identical elements that can be connected to the housing base body optionally at one or the other end face.

[0008] In a structural design of the threaded connection that is fundamentally different from the previously described variants, it is provided that the element used to adjust the receiving area, in particular in the form of a housing cover, has an internal thread that interacts with an external thread formed on the housing base body. In structural terms, such a design can be realized by the element being designed, for example, in a cup-shaped manner with a through-opening for the spindle, wherein the internal thread is formed on a radially circumferential wall of the element. Such a structural design has the particular advantage that the housing base body orin whose recess for receiving the drive element no thread has to be formed, which may otherwise have disadvantages for manufacturing reasons or for functional reasons, in particular with regard to the mounting of the drive element.

[0009] It is particularly preferred, regardless of the arrangement of the threads, if the element is the housing cover. This makes it possible to dispense with separate elements for adjusting the receiving area for the wave spring in the gear housing, so that the housing cover, in addition to defining the receiving space for accommodating the drive element in the housing base part and protecting the receiving space, also takes on the function of adjusting the receiving area for the wave spring. Such a structural design also has the particular advantage that the additional fastening screws usually used in the prior art between the housing cover and the housing base body can be dispensed with, in particular if, for example, the threaded connection between the housing cover and the housing base body is secured or welded using an adhesive, ultrasonic welding or laser beam welding.is fixed and sealed.

[0010] As an alternative to using the housing cover to adjust the size of the receiving area for the shaft ring, it is also conceivable for a bearing element serving to axially or radially support the drive element to simultaneously adjust the receiving area for the wave spring in the receiving space. In this case, the element constituting the bearing element is preferably hat-shaped in cross-section. Such a geometric design of the element has the advantage that the sleeve-shaped section of the bearing element can be provided with the corresponding (external) thread, and thus the receiving area is adjusted via this thread, while at the same time the radially encircling section of the bearing element, which is arranged at right angles to the sleeve-shaped section, serves to axially support the drive element or the wave spring.Furthermore, the sleeve-shaped area in which the (external) thread is formed can also serve for the radial mounting of the drive element, in that this (external) thread interacts, for example, with an internal thread formed on the housing base or on the housing cover.

[0011] The element and the housing base can be manufactured particularly easily and economically with sufficient precision if they are made of plastic and designed as an injection-molded part.

[0012] The invention also includes a comfort drive, in particular a seat adjustment drive in a motor vehicle, with a spindle drive according to the invention as described so far.

[0013] Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawings.

[0014] This shows in: Fig. 1 a partially sectioned side view of a spindle drive according to the invention as a component of a comfort drive for seat adjustment in a motor vehicle, Fig. 2 parts of a gear housing as part of the spindle drive according to the Fig. 1 in a perspective view, Fig. 3 a housing cover, as used in the gearbox housing according to Fig. 2 is used, in a partially sectioned side view, Fig. 4 a simplified longitudinal section through a gear housing with a modified spindle drive and Fig. 5 an element for adjusting the axial play and supporting the spindle, as is the case with Fig. 4 is used, in perspective view.

[0015] Identical elements or elements with the same function are provided with the same reference numbers in the figures.

[0016] In the Fig. 1 shows a spindle drive 10 as a component of a comfort drive 100 in a motor vehicle. The comfort drive 100 is designed in particular as a seat adjustment drive for adjusting a seat 1. Alternatively, however, the spindle drive 10 can also be used for steering column adjustment.

[0017] A spindle drive 10 comprises, in a manner known per se, a drive motor 12 configured as an electric motor, which is connected to a gear housing 15. The gear housing 15, which is made in particular of plastic and is formed as an injection-molded part, comprises a housing base body 16 with a connecting flange 17, via which the housing base body 16 is connected to the drive motor 12. Furthermore, the multi-part gear housing 15 comprises, for example, two identically designed housing covers 18, 20, which are also made of plastic and are formed as injection-molded parts. Fig. 1, the two housing covers 18, 20 are shown in simplified form. The housing base body 16 has a recess 22, which, together with the two housing covers 18, 20, defines a receiving space 24 for a drive element 25. According to DE 10 2016 2003 639 A1 of the applicant, the drive element 25 is designed as a worm wheel 26 with external teeth and is rotated via a drive worm or a drive gear (not shown in the figures) connected to the drive motor 12.

[0018] The drive element 25 is rotationally fixedly connected to a spindle 28, which is made of metal and extends through the gear housing 15 and the two housing covers 18, 20. Outside the gear housing 15, a spindle nut 30 is arranged on the spindle 28 at a distance from the spindle nut. This spindle nut is in turn coupled at least indirectly to the element or seat 1 to be adjusted. When the spindle 28 rotates about its longitudinal or rotational axis 32, the spindle nut 30, which is rotationally fixed with respect to the rotational axis 32, moves in the direction of the double arrow 34, depending on the direction of rotation of the spindle 28, and thereby at least indirectly moves the seat 1.

[0019] The drive element 25, made of plastic, in particular POM, is arranged within the receiving space 24 of the gear housing 15 without axial play. For this purpose, the drive element 25 has an axle stub 36, 38 in the axial direction, which serves for radial bearing in the respective housing cover 18, 20. While one end face of the drive element 25 axially (directly) rests against the housing cover 20, an annular receiving area 39 for receiving a shaft ring 37 is formed between the other housing cover 18 and the enlarged diameter area of ​​the drive element 25. The shaft ring 37 serves to compensate for any axial play formed between the two housing covers 18, 20 and the drive element 25.

[0020] What is essential to the invention is that, as can be seen in particular from the Fig. 2 and Fig. 3, the respective housing cover 18, 20, shown as an example on the housing cover 18, forms an element 40 which serves to adjust the size of the receiving area 39 for the shaft ring 37 within the receiving space 24 of the gear housing 15. For this purpose, an internal thread 43 is formed on an inner wall 42 of the housing base body 16 over the entire extent in the direction of the axis of rotation 32 of the spindle 28. This internal thread 43 is part of a threaded connection 45, which additionally comprises an external thread 46 formed on the outer circumference of the (annular) housing cover 18, 20. When the respective housing cover 18, 20 is rotated about the threaded connection 45 arranged coaxially to the axis of rotation 32, the housing cover 18, 20 can thus be inserted more or less into the housing base body 16 or 18, depending on the direction of rotation of the housing cover 18, 20.axially screw in the receiving space 24 so that the receiving area 39 for the shaft ring 37 can have a defined size. After mounting the shaft ring 37 in the receiving area 39 having the defined size, the axial play of the drive element 25 is then set to zero.

[0021] To pass the spindle 28 through the respective housing cover 18, 20, the latter has a through-opening 48 arranged concentrically to its longitudinal axis 49, wherein the longitudinal axis 49 is in turn arranged concentrically to the axis of rotation 32 of the spindle 28 or to the threaded connection 45. Furthermore, radially outwardly projecting projections 50 are formed on the end face of the housing cover 18, 20 facing away from the housing base body 16, which projections serve as a tool engagement surface for a tool (not shown), so that the respective housing cover 18, 20 can be rotated, in particular by machine.

[0022] In the Fig. 4 and Fig. 5, the element 40a is not part of the housing cover 18a, 20a, but rather part of a bearing element 52, 54 for the axial and / or radial mounting of the drive element 25 or the spindle 28. According to the illustration of Fig. 5, the bearing element 52, 54, which is essentially hat-shaped in cross-section, has an external thread 55 in its sleeve-shaped section for supporting the spindle 28, which, for example, cooperates with an internal thread 58 formed in the region of a through-opening 56 of the housing cover 18a, 20a to form the threaded connection 45a. The housing cover 18a, 20a is in turn connected to the housing base body 16a in a manner not shown, in particular via fastening screws, as known per se from the prior art.

[0023] The spindle drive 10 described so far can be modified or altered in a variety of ways without deviating from the inventive concept. For example, in the embodiment in which the element 40 is formed by the housing cover 18, 20, it is conceivable to design the housing cover 18, 20 with an approximately hat-shaped cross-section, with an internal thread formed on the inner wall of the radially circumferential section, which in turn interacts with an external thread formed in a partial area, in particular in the area of ​​the end faces of the housing base body 16. Furthermore, the invention is not intended to be limited to the use of a shaft ring 37 for adjusting axial play. Rather, differently designed elements having resilient or elastic properties can also be provided for this purpose.

Claims

[1] Spindle drive (10), with a gear housing (15) connected to a drive motor (12), wherein the gear housing (15) has a housing base body (16; 16a) and at least one housing cover (18; 18a, 20; 20a) connected to the housing base body (16; 16a), wherein the housing base body (16; 16a) and the at least one housing cover (18; 18a, 20; 20a) delimit a receiving space (24) for a drive element (25) cooperating with the drive motor (12), wherein the drive element (25) is connected to a spindle (28) which penetrates the receiving space (24), wherein means (37), in particular in the form of a shaft ring, are provided for arranging the drive element (25) in the receiving space (24) without axial play, and wherein the means (37) are arranged in a receiving area (39) in the receiving space (24) are arranged, characterized bythat at least one element (40; 40a) is provided which enables adjustment of the size of the receiving area (39) via a threaded connection (45; 45a) formed on the element (40; 40a) and the housing base body (16) or the at least one housing cover (18a, 20a), which extends coaxially to the axis of rotation (32) of the spindle (28). [2] Spindle drive according to claim 1, characterized by that the element (40; 40a) has an external thread (46; 55) which cooperates with an internal thread (42; 58) which is formed on an inner wall (42) of the housing base body (16) or the housing cover (18a, 20a) which delimits the receiving space (24). [3] Spindle drive according to claim 2, characterized bythat the internal thread (42) is formed on the housing base body (16) over the entire height running in the direction of the axis of rotation (32) of the spindle (28), and that two elements (40) are provided which are arranged on opposite end faces of the housing base body (16). [4] Spindle drive according to claim 1, characterized by that the element (40) has an internal thread which cooperates with an external thread formed on the housing base body (16). [5] Spindle drive according to one of claims 1 to 4, characterized by that the element (40) is the housing cover (18, 20). [6] Spindle drive according to one of claims 1 to 4, characterized by that the element (40a) is a bearing element (52, 54) which is preferably hat-shaped in cross section. [7] Spindle drive according to one of claims 1 to 5, characterized by that the housing base body (16) and the element (40) are made of plastic and are designed as an injection-molded part. [8] Spindle drive according to one of claims 1 to 7, characterized by that the element (40; 40a) is annular with a through opening (48) for the spindle (28) - and in particular has an axial contact surface for the drive element (25). [9] Spindle drive according to one of claims 1 to 8, characterized by that the drive element (25) is a worm wheel and consists of plastic, in particular POM. [10] Spindle drive according to one of claims 1 to 9, characterized by that the means (37) is designed as an axial spring element which is pressed axially against the drive element (25) by the at least one screwable element (40; 40a). [11] Comfort drive (100), in particular seat adjustment drive, with a spindle drive (10) which is designed according to one of claims 1 to 10.

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