Spindle drive and comfort drive with a spindle drive

Abstract

Spindle drive (10), with a gear housing (15; 15a; 15b) which has a housing base body (16) and at least one housing cover (20; 20b) closing an interior space (18) of the housing base body (16), wherein a worm wheel (22) is rotatably mounted in the interior space (18), which worm wheel interacts with a toothing (26) with a toothing region (48) of a rotatable section (46) of a drive motor (12), wherein the axes of rotation (24, 50) of the worm wheel (22) and of the toothing region (48) have an axial distance (a), wherein the worm wheel (22) is arranged in operative connection with a spindle (32) which passes through the at least one housing cover (20; 20b), wherein the worm wheel (22), viewed in the direction of its axis of rotation (24), is arranged on both sides of the toothing (26) in a respective the worm wheel (22) is mounted in a bearing section (28, 30) radially encompassing a bearing bore (64; 64a), characterized in that the bearing bore (64;64a) is formed in a bearing element (60; 60a; 60b), that the bearing element (60; 60a; 60b) is arranged in the housing base body (16) or the at least one housing cover (20; 20b), that the longitudinal axis (66) of the bearing bore (64; 64a) is arranged eccentrically to a longitudinal axis (57; 72) of the bearing element (60; 60a; 60b), and that the bearing element (60; 60a; 60b) is arranged in a form-fitting manner in the housing base body (16) or the housing cover (20) in an opposite recess (52; 52a), such that the bearing element (60; 60a; 60b) in the housing base body (16) or in the housing cover (20) in at least two different positions to form differently sized axis distances (a) can be positioned.;

Description

Prior ArtThe invention relates to a spindle drive according to the preamble of claim 1. Furthermore, the invention relates to a comfort drive, in particular a seat adjustment drive, having a spindle drive according to the invention.From DE 10 2016 203 639 A1 of the applicant, a spindle drive having the features of the preamble of claim 1 is known. The known spindle drive is characterized by a transmission housing of multi-part design, wherein the transmission housing comprises a housing base body and at least one housing cover closing the housing base body in the region of an opening. The housing base body forms an interior for receiving components of the spindle drive. In particular, a spindle connected to a worm wheel projects into the interior of the gear housing. The worm wheel meshes in the interior of the housing base body with a counter element in the form of a toothed section arranged on an armature shaft of a drive motor designed as an electric motor, in order, depending on the embodiment, either to rotate the spindle about its longitudinal axis or else to move the spindle in its longitudinal direction, in order to be able to move an element (seat) to be adjusted therewith.The radial mounting of the worm wheel or of the spindle in the region of the gear housing takes place in the housing covers, but can also take place by separate elements in the region of the housing base body. When the worm wheel is mounted in the housing cover, these have corresponding through-openings or blind-hole bores. The positioning of the through-bores or blind-end bores in the housing covers determines, when the gear housing is mounted, the axial distance between the worm wheel or the spindle and the armature shaft or the toothed section interacting with the worm wheel. This is predefined in the case of a predefined transmission housing or corresponding housing covers by their geometry.For custom adaptation of a spindle drive, it can be provided to vary the axial distance between the armature shaft and the worm wheel or the spindle and thus between the toothed section and the worm wheel, in order to be able to use a worm wheel with an enlarged diameter, for example. In the prior art, this requires specially designed gear housings with correspondingly high tool costs, since the essential components of the gear housings usually consist of plastic or of aluminum and are designed as injection molded parts or die cast parts.Disclosure of the InventionThe spindle drive according to the invention having the features of claim 1 has the advantage that an adaptation of the spindle drive or a variation of the axial distances between the armature shaft and the spindle is possible using the same components of the transmission housing. In other words, this means that with one and the same tools it is possible to produce housing base bodies or housing covers which are suitable for being able to form different axial distances between the worm wheel and the armature shaft. This is accomplished according to the teaching of the invention in that the bearing bore for the worm wheel is formed in a bearing element, that the bearing element is arranged in the housing base body or the at least one housing cover, that the longitudinal axis of the bearing bore is arranged eccentrically to a longitudinal axis of the bearing element, and that the bearing element is arranged in a form-fitting manner in the housing base body or the housing cover in an diametrically opposite recess, such that the bearing element can be positioned in the housing base body or in the housing cover in at least two different positions for forming axis distances of different sizes between the worm wheel and the armature shaft. The proposed solution according to the invention thus makes it possible, by means of (additional) bearing elements with eccentrically arranged bearing bores for the worm wheel, to position the bearing elements in at least two different positions, using the same housing cover or a housing base body which is always the same, in order to thus influence the axial distance.Advantageous refinements of the spindle drive according to the invention are listed in the dependent claims.A first possible geometric configuration of the bearing element and of the receptacle in the housing cover or in the housing base body provides that the bearing element and the recess have an approximately circular outer shape which is arranged concentrically with respect to the longitudinal axis of the bearing element. In particular, in such a geometry for setting different axial distances, it is provided that the bearing element has projections or depressions arranged on the outer periphery at uniform angular distances about a longitudinal axis of the bearing element, which projections or depressions cooperate with diametrically opposed depressions or projections of the recess in the housing base body or the housing cover. Such a configuration thus makes it possible, in the case of a number of n projections or depressions, to insert the bearing element in n different angular positions in the receptacle in the housing cover or the housing base body and to correspondingly set n different axial spacings.In an alternative geometric configuration of the bearing element, the latter has an outer contour which is of elongate configuration and has an axis of symmetry. Such an, for example oval, outer contour in the bearing element, in which the bearing bore is arranged eccentrically or eccentrically on the main axis, thus makes it possible to arrange the bearing element in two positions in the housing cover or the housing base body, which positions are offset by 180° with respect to one another, and thereby to be able to form two different axial distances.A further structural embodiment of the invention provides that both bearing elements are arranged in the housing base body. Such a configuration makes it possible in particular to be able to use housing covers which are exposed to relatively simple and low mechanical loads.An alternative structural embodiment of the spindle drive provides that at least one bearing element is formed monolithically with the housing cover, and that the housing cover can be connected to the housing base body in different angular positions. Such a configuration reduces the number of required components in that the bearing element is not formed as a separate element, but is a component of the housing cover.To form bearing elements of particularly compact construction in the axial direction, these are preferably of ring- or plate-shaped design.Furthermore, for reasons of the greatest possible wear resistance of the bearing element, it is provided that this is made of metal. Alternatively, however, it can also be provided to form these from plastic.In an arrangement of the bearing element in the region of the housing base body, it is provided for the simplest possible fabrication of the housing base body that the diametrically opposed recess formed in the housing base body extends over the entire axial extent of the housing base body in relation to the recess of the bearing element.The invention also comprises a comfort drive, in particular a seat adjustment drive, having a spindle drive according to the invention as described thus far.Further advantages, features and details of the invention are evident from the following description of preferred exemplary embodiments and with reference to the drawing.This is shown in: FIG. 1 is a partially cut side view of a spindle drive designed as a seat adjustment drive, FIG. 2 shows a perspective illustration of a housing base body with a bearing element arranged therein, FIG. 3 shows the components according to FIG. 2 in a separate arrangement from one another, FIG. 4 shows the bearing element as used in the arrangement according to FIGS. 2 and 3 in a plan view, FIGS. 5 and 6 are simplified representations of a modified transmission housing using oval bearing elements; and FIG. 7 shows a representation of the bearing element as used in the spindle drives according to FIGS. 5 and 6, in a plan view.Identical elements or elements with the same function are provided with the same reference numbers in the figures.FIG. 1 shows a spindle drive 10 as a component of a comfort drive 100 serving as a seat adjustment drive for adjusting a seat 1. However, the spindle drive 10 can also be a component of a steering column adjustment, for example. The spindle drive 10 comprises an electric motor 12 serving as a drive motor, to the housing of which a transmission housing 15 of multipart design is flanged or fastened. The transmission housing 15 has a housing base body 16, on which a connection flange 17 for fastening the transmission housing 15 to the electric motor 12 is monolithically formed. The housing base body 16 has an interior 18, the opening(s) of which are closed by means of at least one housing cover 20. Depending on requirements, the housing base body 16 is either made of plastic or of metal (in particular aluminum) and is formed in a chipless production process (plastic injection-molded part or aluminum die-cast part).The at least one housing cover 20 is preferably designed as a plastic injection molded part. Within the interior 18 of the gear housing 15 a worm wheel 22, which is particularly well recognizable in FIGS. 1 and 3 and is preferably made of plastic, is rotatably mounted.According to FIG. 3, the worm wheel 22 has a toothing region 25 with a helical toothing 26 arranged in a region axially central with respect to the axis of rotation 24 of the worm wheel 22. On both sides of the toothed region 25, an annular bearing section 28, 30 is provided on the worm wheel 22.In an embodiment of the spindle drive 10, in which a spindle 32 operatively connected to the worm wheel 22 is arranged rotatably about its longitudinal or rotational axis 34 identical to the rotational axis 24, the worm wheel 22 has a centrally arranged through-opening 36, in the region of which the spindle 32 is connected to the worm wheel 22 in a rotationally fixed manner. In practice, this is done by injection molding the plastic of the worm wheel 22 onto the spindle 32 made of metal.According to FIG. 1, the spindle 32 protrudes from the gear housing 15 and, as is known per se from the prior art, has a thread-like spindle thread 38 on which a spindle nut 40 is arranged. The spindle nut 40 arranged rotationally fixedly with respect to the axis of rotation 34 of the spindle 32 is connected at least indirectly to the seat 1, so that when the spindle 32 rotates about the axis of rotation 34, the spindle nut 40 is moved longitudinally in the direction of the double arrow 42 in order thereby to adjust the seat 1. In the exemplary embodiment shown in FIG. 1, a fastening section 44 with a customer-specific fastening option, not shown in detail, on a body structure is furthermore integrally formed on the housing base body 16. Alternatively, however, it is also conceivable for the fastening region 44 to be arranged on the at least one housing cover 20.The worm wheel 22 is driven via its helical toothing 26 by means of the electric motor 12, for which purpose the electric motor 12 has a section 46 illustrated in FIG. 1 with a toothing region 48 which projects into the gear housing 15 or the housing base body 16 as far as into the interior 18, wherein the toothing region 48 meshes with the helical toothing 26 of the worm wheel 22. Between the longitudinal axis 50 of the section 46 and the rotational axis 24 of the worm wheel 22 arranged perpendicular thereto, an axial distance a is formed in accordance with FIGS. 2 and 3. This axial distance a can be adjusted in a manner which is application- or customer-specific to the spindle drive 10. In this regard, reference is first made to the illustration of FIGS. 2 and 3. It can be seen from this that an approximately circular recess 52 is formed in the housing base body 16 in the region of the interior 18, which recess is aligned in the axial direction, i.e. in the direction of the axis of rotation 24 of the worm wheel 22, and which recess has projections 54 or depressions 56 in the manner of the mating contour of a gearwheel, which recesses are arranged at respectively uniform angular distances about a longitudinal axis 57 of the recess 52. The recess 52 preferably extends over the entire axial length or height of the interior 18 of the housing base body 16. the projections 24 or depressions 56 interact in a form-fitting manner with a corresponding mating contour 58 of two disk-shaped or annular bearing elements 60, preferably made of metal, of which only the one bearing element 60 interacting with the bearing section 30 of the worm wheel 22 can be seen in FIGS. 2 and 3.According to the illustration in FIG. 2, the one end face 62 of the bearing element 60 terminates flush with the corresponding end face 63 of the housing base body 16, wherein the housing cover 20 axially (directly) adjoins the bearing element 60 or the housing base body 16. According to the illustration of FIGS. 2 to 4, the bearing element 60 has a bearing bore 64 for receiving the bearing section 28, 30 of the spindle 32 in order to radially support the worm wheel 22. It is essential here that a longitudinal axis 66 of the bearing bore 64, which coincides with the axes of rotation 24, 34 of the worm wheel 22 and of the spindle 32, is arranged eccentrically by a dimension e with respect to the (outer) mating contour 58 or the longitudinal axis 57. As a result of the positive connection between the bearing element 60 and the recess 52 in the housing base body 16, the bearing element 60 can thereby be inserted in different rotational angle positions in the housing base body 16 in accordance with the number of projections 54 or depressions 56, as a result of which different axial distances a are produced between the section 46 and the rotational axis 24 of the worm wheel 22.FIG. 5 shows a greatly simplified illustration of a modified transmission housing 15 awhich is formed using two bearing elements 60 awhich is shown in FIG. 7 in a single illustration. The bearing element 60 ahas an oval basic shape with an outer contour 70 and a longitudinal or main axis 72. The bearing bore 64 ais arranged on the main axis 72 by a dimension e eccentrically with respect to the axial extension of the bearing element 60 ain the direction of the main axis 72. Such a configuration of the bearing element 60 amakes it possible to insert the bearing element 60 ain two positions different by 180° within the recesses 52 aof the gearbox housing 15 a, which are designed diametrically opposed to the outer contour 70 of the bearing element 60 a.Finally, FIG. 6 shows a transmission housing 15 b,in which a bearing element 60 acorresponding to FIGS. 5 and 7 is used, and a bearing element 60 bwhich has a section 74 which is shaped corresponding to the bearing element 60 a,wherein the section 74 is monolithically connected to the housing cover 20 b.The spindle drive 10 described thus far can be modified or modified in a variety of ways without departing from the concept of the invention.

Claims

Spindle drive (10), having a transmission housing (15; 15a; 15b) which has a housing base body (16) and at least one housing cover (20; 20b) which closes an interior space (18) of the housing base body (16), wherein a worm wheel (22) is rotatably mounted in the interior space (18), said worm wheel interacting with a toothing (26) with a toothing region (48) of a rotatable section (46) of a drive motor (12), wherein the axes of rotation (24, 50) of the worm wheel (22) and of the toothing region (48) have an axial spacing (a), wherein the worm wheel (22) is arranged in operative connection with a spindle (32) which traverses the at least one housing cover (20; 20b), wherein the worm wheel (22), as viewed in the direction of its axis of rotation (24), on both sides of the toothing (26) in a bearing bore (64; which radially surrounds the worm wheel (22) in a bearing section (28, 30); 64a), characterized in that the bearing bore (64; 64a) is formed in a bearing element (60; 60a; 60b), in that the bearing element (60; 60a; 60b) is arranged in the housing base body (16) or the at least one housing cover (20; 20b), in that the longitudinal axis (66) of the bearing bore (64; 64a) is arranged eccentrically with respect to a longitudinal axis (57; 72) of the bearing element (60; 60a; 60b), and in that the bearing element (60; 60a; 60b) is arranged in a form-fit manner in the housing base body (16) or the housing cover (20) in an diametrically opposed recess (52; 52a), in such a way that the bearing element (60; 60a; 60b) is arranged in a form-fit manner; 60 b) can be positioned in the housing base body ( 16) or in the housing cover ( 20) in at least two different positions in order to form different axial distances (a).Spindle drive according to claim 1, characterised in that the bearing element (60) and the recess (52) have an approximately circular outer shape which is arranged concentrically with respect to the longitudinal axis (57) of the bearing element (60).Spindle drive according to claim 2, characterised in that the bearing element (60) has projections or depressions arranged on the outer periphery at uniform angular spacings about the longitudinal axis (57) of the bearing element (60), which projections or depressions cooperate with diametrically opposed depressions (56) or projections (54) of the recess (52) in the housing base body (16) or the housing cover (20) - wherein in particular the depressions (56) and corresponding projections (54) are formed as positively locking teeth.Spindle drive according to claim 1, characterised in that an outer contour (70) of the bearing element (60a; 60b) is oval.Spindle drive according to one of Claims 1 to 4, characterized in that both bearing elements (60; 60a) are arranged in the housing base body (16).Spindle drive according to one of Claims 1 to 4, characterized in that at least one bearing element (60b) is formed monolithically with the housing cover (20b).Spindle drive according to one of Claims 1 to 6, characterized in that the bearing element (60; 60a; 60b) is of annular or plate-shaped design.Spindle drive according to one of Claims 1 to 7, characterized in that the bearing element (60: 60a; 60b) consists of metal or plastic.Spindle drive according to one of Claims 1 to 8, characterized in that the recess (52) formed in the housing base body (16) is formed for receiving the bearing element (60) over the entire axial extent of the housing base body (16) - and in particular two identically constructed bearing elements (60; 60a; 60b) are inserted into the recess (52).Comfort drive (100), in particular seat adjustment drive, having a spindle drive (10) which is designed according to one of Claims 1 to 9.

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