Spindle gear and drive unit of an electric seat drive

Abstract

Spindle drive (1) of an electric seat drive, comprising - a gear housing (2) for supporting a worm wheel (3) and a worm (33), wherein the worm (33) meshes with the worm wheel (3), - a threaded spindle (4, 5) connected to the worm gear (3), - a first lid (6), and - a second lid (7), - wherein the first cover (6) and the second cover (7) are attached to the gearbox housing (2) parallel to each other, - wherein the threaded spindle (4, 5) is guided through the first cover (6), and - wherein the first cover (6) is attached to the gearbox housing (2) independently of the second cover (7), - wherein a rotary spindle (4) or alternatively a plunge spindle (5) can be inserted into the gearbox housing (2) as a threaded spindle (4, 5), - wherein the second cover (7) has a central through-opening in the direction of the threaded spindle axis, which is suitable for supporting the plunger (5), and the through-opening can be closed with a compensating disc (15) in order to support the rotary spindle (4) in the gearbox housing (2), wherein the rotary spindle (4) rests axially against the compensating disc (15).

Description

State of the art

[0001] The present invention relates to a spindle drive for an electric seat drive. Furthermore, the invention relates to a drive unit for an electric seat drive. In particular, the electric seat drive is usable in a vehicle.

[0002] Spindle motors for electrically adjusting a seat are known from the prior art. If such a seat is used in a vehicle, the spindle motor must be able to absorb both operating forces and crash forces via a gear housing. The gear housing has a customer interface through which the gear housing can be attached to other components of the vehicle or the seat. The mounting direction, in which the spindle is inserted into the gear housing, is usually oriented perpendicular to the spindle axis.

[0003] However, a concept as shown in the prior art has several disadvantages. For one thing, it is not possible to use the drive for both a left and a right version. Instead, different gear housings must be provided. A left-hand version is understood in particular to mean that the spindle gear can be used to adjust a seat that is installed on the left in a vehicle in the direction of travel. Likewise, a right-hand version is understood to mean that the spindle gear can be used to adjust a seat installed on the right in the direction of travel. Furthermore, the modularity and thus the use of identical parts in different applications are severely restricted by an assembly concept such as the prior art.

[0004] DE 699 14 769 T2 discloses a reduction gear of a displacement motor in which identical end covers are attached to the front and rear surfaces of a gear housing body axially to the longitudinal displacement screw shaft on both sides.

[0005] US 4 962 963 A shows a seat adjustment device in which a through-penetrating spindle is mounted in a gear housing and is motor-driven via a multi-stage worm gear.

[0006] DE 103 62 040 B4 discloses a gear for a spindle drive, which is overlapped by two shells made of rubber or a corresponding material for noise insulation and is housed in a substantially U-shaped bearing bracket. Disclosure of the invention

[0007] The spindle gear of an electric seat drive according to the invention allows a reduction in the variety of parts, thereby achieving a particular cost reduction. In particular, a gear housing of the spindle gear allows both a left-hand and a right-hand version of the spindle gear. The spindle gear can therefore be used in a modular manner. Furthermore, crash resistance can be adjusted in a modular manner by manufacturing individual components from materials with different strengths. The spindle gear of an electric seat drive according to the invention comprises a gear housing, a threaded spindle, a first cover, and a second cover. The gear housing is designed to support a worm gear and a worm and can be one-piece or multi-piece. The worm is designed to mesh with the worm gear. The threaded spindle is connected to the worm gear.This enables power transmission and / or torque transmission between the worm gear and the threaded spindle. The first cover and the second cover are fastened parallel to one another on the gear housing. In particular, the first cover and the second cover extend parallel to the worm gear. Provision is made for the threaded spindle to pass through the first cover. In particular, it is preferred that the first cover and the second cover cover the worm gear. Furthermore, provision is made for the first cover to be fastened to the gear housing independently of the second cover. The second cover in particular has a variable connection geometry, via which the spindle gear can be fastened to a component of a vehicle or a seat. Since the second cover is a separate component, this connection geometry can be designed differently for different applications.The first cover, in particular, has a sealing element with which the first cover can be sealed against the threaded spindle guided through the first cover. By attaching the first cover independently of the second cover, the spindle drive has a modular design, since the first cover, in particular, is replaceable independently of the second cover. Thus, the first cover and / or the second cover can be individually adapted to existing conditions, in particular with regard to the operating forces and / or crash forces to be absorbed. According to the invention, the threaded spindle is a rotary spindle or a plunger spindle. In the rotary spindle, the threaded spindle is rotationally fixed to the worm gear, allowing rotation from the worm gear to be transferred to the rotary spindle. The rotary spindle has a spindle nut that is guided on the rotary spindle, with the spindle nut being rotationally fixed. The spindle nut can thus be moved by rotating the rotary spindle.

[0008] The subclaims contain preferred developments of the invention.

[0009] The gear housing is preferably designed symmetrically to a plane perpendicular to the threaded spindle. The plane of symmetry is located, in particular, centrally in the gear housing between the first cover and the second cover. This allows both the first cover and the second cover to be attached to all sides of the gear housing, thereby allowing the threaded spindle to be mounted on all sides of the gear housing. This enables, in particular, left- and right-hand mounting when using the same spindle gear.

[0010] In particular, each opening in the gear housing can be closed with the first cover and the second cover. It is provided that the respective openings run perpendicular to the threaded spindle. It is particularly provided that each opening in the gear housing can be closed with each cover, i.e., with both the first cover and the second cover. This ensures the modularity of the spindle drive. The gear housing preferably has two such openings.

[0011] The gear housing is advantageously completely closed by the first cover and the second cover. The only exception to this is an existing drive opening for connecting a drive motor to the worm. The drive opening is irrelevant to the invention and is therefore not considered. Thus, it is particularly provided that the gear housing has only two openings, each of the openings being closed by either the first cover or the second cover. Particularly advantageously, the respective openings are completely closed by the first cover and the second cover. In particular, therefore, no additional covers are required.

[0012] The first cover and the second cover can advantageously be screwed to the gearbox housing independently of each other. This creates a secure and reliable connection between the first cover and the gearbox housing, as well as between the second cover and the gearbox housing. Because the first cover and the second cover are individually screwed together, both the first cover and the second cover can be replaced very easily and with little effort, thus ensuring a high degree of modularity. In particular, the first cover and / or the second cover can be replaced in such a way that a customized, particularly high-strength, material is used depending on the application.

[0013] In an alternative, it is preferably provided that the spindle gear has at least one mounting screw. The at least one mounting screw fastens the first cover or simultaneously the first cover and the second cover to the counter element. This particularly simplifies assembly of the two covers on the gear housing. Particularly advantageously, the first cover has a counter thread into which the mounting screw can be screwed. The counter thread can also be a thread created by the mounting screw itself. If the second cover is to be fastened to the gear housing by the mounting screw in addition to the first cover, it is preferably provided that the second cover has at least one bore through which the mounting screw can be guided.

[0014] In an advantageous embodiment, the first cover and / or the second cover are each formed as a single piece. In particular, the first cover and / or the second cover are each cast. This single-piece design makes both the first cover and the second cover very simple and cost-effective to manufacture. Furthermore, assembly of the spindle gear is simplified.

[0015] The first cover and / or the second cover are advantageously made of a plastic or metal. In particular, metal construction is intended for use when increased crash forces must be absorbed. Plastic construction saves weight, while also being cost-effective and low-complexity to manufacture.

[0016] Preferably, the spindle nut is connected to a component of a seat, whereby the seat is displaceable relative to the spindle gear. If, on the other hand, the threaded spindle is a plunger spindle, it is provided that the plunger spindle is arranged in a rotationally fixed manner. In particular, there is no transmission of rotation from the worm gear to the plunger spindle. Rather, it is provided that the worm gear converts a rotation into a translation of the plunger spindle. This is achieved in particular by the worm gear having an internal thread into which a thread of the plunger spindle engages. The plunger spindle is advantageously attached in a rotationally fixed manner to a component of the seat, which in turn enables movement of the seat relative to the spindle gear.

[0017] Thus, the invention comprises a system consisting of the identical components of the gear housing, the first and the second housing cover, wherein either a submersible spindle or a rotary spindle can be mounted alternatively in the gear housing.

[0018] If the gearbox housing is designed with receptacles for fastening elements as a vehicle connection geometry, the seat drive can also be attached to the seat or the vehicle if a replacement spindle is mounted in the gearbox housing, which blocks the way for a hinge pin in the through hole transverse to the gearbox spindle axis through a central opening in the cover.

[0019] If the first cover has a central through-hole for supporting the submersible spindle in the direction of the threaded spindle axis, which can be closed with a shim, the same cover can be used to support both a submersible spindle through the through-hole and, alternatively, a rotary spindle, which optionally rests axially against the shim.

[0020] For this purpose, a recess is formed in the first cover to accommodate the shim, so that the first cover sits flush with the gearbox housing with or without the shim.

[0021] Finally, the invention relates to a drive unit of an electric seat drive. The drive unit comprises a drive motor and a spindle gear as described above. It is provided that the worm is driven by the drive motor. The drive unit according to the invention can thus be used modularly, since, in particular, different first covers and / or second covers can be attached in order to absorb different operating forces and / or crash forces. Furthermore, the drive unit advantageously allows installation in both the left-hand and right-hand versions, which makes the drive unit versatile. In this way, the requirements for additional components are reduced, in particular. Short description of the drawing

[0022] Embodiments of the invention are described in detail below with reference to the accompanying drawings. In the drawing: Fig. 1 a schematic illustration of a drive unit according to an embodiment of the invention. Embodiment of the invention

[0023] Fig. Figure 1 shows a drive unit 10 according to one embodiment of the invention. The drive unit 10 comprises a spindle gear 1 and a drive motor 11. The drive unit 10 is designed to enable adjustment of a seat of a motor vehicle.

[0024] To adjust the seat, the spindle gear 1 has a gear housing 2 in which both a worm gear 3 and a worm 33 can be mounted. The worm 33 is driven by the drive motor 11 and is arranged, in particular, on its armature shaft. The worm 33 extends through a lateral opening 53 in the gear housing 2 and meshes with the worm gear 3, so that rotation can be transmitted to the worm gear 3. The worm gear 3, in turn, drives a threaded spindle 4, 5, via which the seat can be moved.

[0025] The gear housing 2 has a non-visible drive opening through which a connection between the drive motor 11 and the worm 33 is possible. By fastening the drive motor 11 to the gear housing 2, the drive opening is covered. Fig. 1, the armature shaft of the drive motor 11 engages through the drive opening into the gear housing 2. Alternatively, the gear housing 2 encompasses, in particular, the entire drive motor 11.

[0026] In Fig. 1 shows two different versions of the spindle gear 1, which differ particularly in the type of threaded spindle 4, 5. In a first version 100, a rotary spindle 4 is used, while in a second version 200, a plunger spindle 5 is used. In both versions, the gear housing 2 and the first and second covers 6, 7 are identical.

[0027] In the first embodiment 100, i.e., when using the rotating spindle 4, the worm gear 3 is rotationally fixedly connected to the rotating spindle 4. This enables a transmission of rotation from the worm gear 3 to the rotating spindle 4. A spindle nut 14 is mounted on the rotating spindle 4, wherein the spindle nut 14 is rotationally fixed. In this way, upon rotation of the worm gear 3 and thus of the rotating spindle 4, a translation of the spindle nut 14 occurs along a central axis of the rotating spindle 4. The rotating spindle 4 also has an end stop 16, at which the translational movement of the spindle nut 14 is stopped.

[0028] Furthermore, a wave spring 18 is provided, which can be used to compensate for any play between the rotating spindle 4 and the worm gear 3. A shim 15 can be used to cover a central through-hole for the plunger spindle in order to support the rotating spindle within the gear housing 2. The shim 15 is inserted into a recess in the second cover 7 and axially seals the gear housing 2. Finally, a thrust washer 13 is provided.

[0029] If the threaded spindle 4, 5 is a submersible spindle 5 according to the second embodiment 200, the submersible spindle 5 is attached to the worm wheel 3 in such a way that no rotation can be transmitted between the worm wheel 3 and the submersible spindle 5. Rather, a rotation of the worm wheel 3 causes a translation of the submersible spindle 5 relative to the worm wheel 3. In particular, the worm wheel 3 has an internal thread into which a thread of the submersible spindle 5 engages. The submersible spindle 5 is arranged in a rotationally fixed manner, so that upon rotation of the worm wheel 3, a displacement of the submersible spindle 5 occurs due to the worm wheel 3.

[0030] Again, a wave spring 18 is preferably provided, which can compensate for any play in the worm gear 3 and / or the plunger spindle 5. Two thrust washers 13 are also provided.

[0031] Both the first embodiment 100 and the second embodiment 200 each feature a seat connection geometry 17, via which the drive unit 10 can be connected to a seat of a vehicle. In the first embodiment 100, the seat connection geometry 17 is attached to the spindle nut 14; in the second embodiment 200, the seat connection geometry 17 is arranged at one end of the plunger spindle 5. In the second embodiment 200, it is preferably provided that the rotationally fixed arrangement of the plunger spindle 5 is achieved via the seat connection geometry 17, which is connected to a component of the seat.

[0032] The transmission housing 2 is particularly axially symmetrical with respect to the center axis of the threaded spindle 4, 5. The symmetry extends particularly to a plane located centrally between two axial openings 8. The two openings 8 are particularly identical in design. Thus, each of the openings 8 can be closed either by a first cover 6 or by a second cover 7. For correct positioning of the covers 6, 7, centering elements, for example axially extending centering pins, are provided on the transmission housing 2. These then engage in corresponding counter-centering elements (e.g., axial holes) in the covers 6, 7. The threaded spindle 4, 5 is guided through a recess in the first cover 6. The second cover 7 has a vehicle connection geometry 19, via which the second cover 7, and thus the drive unit 10, can be attached to another component of the vehicle.For example, the vehicle connection geometry 19 is designed as a through-bore 29 in the second cover 7 transverse to the center axis of the threaded spindle 4, 5, which can rotatably accommodate a joint pin (not shown). The second cover 7 is designed as a plastic injection-molded part so that the forces from the joint pin can be absorbed noiselessly. The worm gear 3 has two axial extensions 43, which are designed for radial mounting of the worm gear 3 by means of plain bearings. For this purpose, cylindrical, axially extending bearing bushes 40 are formed in the covers 6, 7, which, in the fully assembled state, accommodate the two axial extensions 43 for radial mounting. The symmetrically designed bearing bushes 40 thus form a radial bearing for the worm gear 3. Thus, as a modular system, different spindle modules can be attached to the left or right side of the identical gearbox housing base body 2.Preferably, both the radial and the axial support of the worm wheel 3 is realized only by the two covers 6, 7 - and in particular not directly by the gear housing base body 2.

[0033] By variably applying either the first cover 6 or the second cover 7 to the respective openings 8, the drive unit 10 can be used modularly. In particular, it is possible to position the threaded spindle 4, 5 as shown in Fig. 1, or the one in Fig. 1, the positions of the first cover 6 and the second cover 7 can be swapped. This allows the drive unit 10 to be mounted on the left or on the right.

[0034] The first cover 6 and the second cover 7 can be attached to the gear housing 2 independently of each other. Fig. 1, first fastening elements 12 and second fastening elements 9 are provided, wherein the first fastening elements 12 are provided for fastening the first cover 6 to the gear housing 2, while the second fastening elements 9 enable fastening of the second cover 7 to the gear housing 2. Due to the independently attachable first cover 6 and second cover 7, the spindle gear 1 and thus the drive unit 10 can be constructed in a modular manner. In particular, different first covers 6 or second covers 7 made of different materials can be easily exchanged, thereby enabling different absorption capacities of operating forces and / or crash forces by the drive unit 10. The first fastening element 12 and the second fastening elements 9 are preferably screws.

[0035] In an alternative embodiment, only the second fastening elements 9 are present in the form of mounting screws. The mounting screws allow the first cover 6 or both the first cover 6 and the second cover 7 to be fastened to the gearbox housing 2. In particular, the first cover 6 is provided with threads into which the mounting screws engage. If, in addition to the first cover 6, the second cover 7 is also to be fastened using the mounting screws, the mounting screws are guided through openings 20 in the second cover 7. By providing only the second fastening elements 9 as mounting screws, production of the drive unit 10 is thus simplified. This always ensures that the first cover 6 can be arranged on the gearbox housing 2 independently of the second cover 7.

[0036] Out of Fig. 1 also shows that the assembly direction of the spindle gear 1 is along a central axis of the threaded spindle 4, 5. Thus, a tool separation perpendicular to the central axis of the threaded spindle 4, 5 is present. In addition, Fig. 1 shows that, in addition to the gear housing 2 and the two covers 6, 7, a number of components are identical between the version with a rotating spindle 4 and the version with a submersible spindle 5. In particular, the thrust washers 13, the wave spring 18, and partially the worm gear 3 are identical. This leads to reduced manufacturing and assembly costs for the drive unit 10, making the drive unit 10 more cost-effective to manufacture.

Claims

[1] Spindle gear (1) of an electric seat drive, comprising - a gear housing (2) for supporting a worm wheel (3) and a worm (33), the worm (33) meshing with the worm wheel (3), - a threaded spindle (4, 5) connected to the worm wheel (3), - a first cover (6), and - a second cover (7), - wherein the first cover (6) and the second cover (7) are fastened parallel to each other to the gear housing (2), - wherein the threaded spindle (4, 5) is guided through the first cover (6), and - wherein the first cover (6) is attached to the gear housing (2) independently of the second cover (7), - wherein a rotary spindle (4) or alternatively a plunger spindle (5) can be inserted into the gear housing (2) as a threaded spindle (4, 5), - wherein the second cover (7) has a central through-opening in the direction of the threaded spindle axis, which is suitable for supporting the immersion spindle (5), and the through-opening can be closed with a compensating disc (15) in order to support the rotating spindle (4) in the gear housing (2), wherein the rotating spindle (4) bears axially against the compensating disc (15). [2] Spindle gear (1) according to claim 1, characterized by that the gear housing (2) is symmetrical to a plane perpendicular to the threaded spindle (4, 5). [3] Spindle gear (1) according to one of the preceding claims, characterized by that the gear housing (2) has openings (8) in the axial direction of the threaded spindle (4, 5), wherein each opening (8) can be closed with the first cover (6) or the second cover (7). [4] Spindle gear (1) according to one of the preceding claims, characterized bythat the openings (8) of the gear housing (2) are covered by the first cover (6) and the second cover (7), wherein a drive opening is formed for connecting a drive motor (11) to the worm (33). [5] Spindle gear (1) according to one of the preceding claims, characterized by that the first cover (6) and the second cover (7) are screwed to the gearbox housing (2) independently of each other. [6] Spindle gear (1) according to one of claims 1 to 4, characterized by at least one mounting screw (12, 9), wherein the mounting screw (12, 9) fastens the first cover (6) or simultaneously the first cover (6) and the second cover (7) to the gear housing (2). [7] Spindle gear (1) according to one of the preceding claims, characterized by that the first cover (6) and / or the second cover (7) are each formed in one piece. [8] Spindle gear (1) according to one of the preceding claims, characterized bythat the first cover (6) and / or the second cover (7) are made of a plastic material or a metal material. [9] Spindle gear (1) according to one of the preceding claims, characterized by that the first cover (6) and / or the second cover (7) have a cylindrical bearing bush (40) into which axial extensions (43) of the worm wheel (3) engage axially. [10] Spindle gear (1) according to one of the preceding claims, characterized by that the openings (8) are symmetrical with respect to a threaded spindle axis. [11] Spindle gear (1) according to one of the preceding claims, characterized by that a through-bore (29) transverse to the gear spindle axis is formed on the first cover (6) or on the second cover (7) as a vehicle connection geometry (19), preferably for fastening the seat drive, which has a rotating spindle (4). [12] Spindle gear (1) according to one of the preceding claims, characterized bythat receptacles for fastening elements are formed on the gear housing (2) as a vehicle connection geometry (19), preferably for fastening the seat drive, which has an exchange spindle (5). [13] Spindle gear (1) according to one of the preceding claims, characterized by that a recess for receiving the compensating disc (15) is formed in the first cover (6) or in the second cover (7), so that the first cover (6) or the second cover (7) lies tightly against the gear housing (2) with or without the compensating disc (15). [14] Drive unit (10) of an electric seat drive, comprising: - a drive motor (11) and - a spindle gear (1) according to one of the preceding claims, wherein the worm (33) of the spindle gear (1) is driven by the drive motor (11), and the spindle gear (1) can be equipped with a rotary spindle (4) or alternatively with a submersible spindle (5).

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