Adjustment device for a vehicle seat

Abstract

Adjusting device (2) for a vehicle seat with a rail system (4) extending in a longitudinal direction (L) with a first rail (6) and a second rail (8) and with a spindle drive (10) which has a spindle (12) and a spindle nut unit (14), wherein the spindle nut unit (14) has a holder and an insert (16) received therein, which forms a spindle nut, wherein the holder is fastened to the first rail (6), wherein the holder is designed as a cage (18) which has a plurality of side walls (30, 30A, 30B, 30C) extending in the longitudinal direction (L), namely in particular two lateral side walls (30A), an upper side wall (30B) and a lower side wall (30C), wherein the cage (18) with the side walls (30, 30A, 30B, 30C) wraps around the insert (16), and that at least one of the side walls (30, 30A, 30B, 30C) are interlaced with the insert (16),such that a form-fit connection acting in the longitudinal direction (L) is formed between the at least one side wall (30, 30A, 30B, 30C) and the insert (16), and wherein the at least one side wall (30, 30A, 30B, 30C) has an open edge in a partial section, which forms an edge contour (32) via which the interlacing takes place and the edge contour (32) forms a plurality of recesses (34) as interlacing elements and tabs (36) located therebetween.

Description

[0001] The invention relates to an adjusting device for a vehicle seat for its longitudinal adjustment.

[0002] The adjustment device comprises a rail system extending in a longitudinal direction with a first and a second rail, as well as a spindle drive. The spindle drive comprises a spindle and a spindle nut unit. The spindle nut unit comprises a holder, particularly designed as a bent sheet metal part, and an insert received therein, which forms a spindle nut that, in cooperation with the spindle, ensures longitudinal adjustment. The spindle nut unit is attached to the first rail via the holder.

[0003] Such spindle drives must be designed to absorb forces acting in the longitudinal direction and, in particular, to be crash-proof so that the forces acting in a crash can be reliably absorbed.

[0004] Such an adjustment device can be found, for example, in DE 10 2020 108 920 A1. The holder consists of a U-shaped sheet metal strip with two opposing sheet metal tabs oriented transversely to the longitudinal direction, through which the spindle is passed. These tabs, oriented transversely to the longitudinal direction, can absorb the forces acting in the longitudinal direction.

[0005] US 2009 / 0243326 A1 discloses a further adjustment device in which the holder is designed as a solid, U-shaped component, which also has two opposite walls transverse to the longitudinal direction, through which the spindle is guided.

[0006] Passing the spindle through the brackets or walls weakens them, so the brackets are only partially crash-resistant or require special precautions to ensure adequate crash safety. This leads, for example, to high material usage and / or high costs.

[0007] US 2006 / 0226674 A1 discloses an adjustment device in which the holder is designed as a bent sheet metal part with a U-shaped cross section and a recess on the upper side into which a spindle nut is inserted, which is supported in a form-fitting manner on the side and end walls of the recess.

[0008] DE 20 2006 009 868 U1 discloses a further adjustment device in which a supporting structure designed as a bent sheet metal part is provided with a cylindrical receiving area, wherein an insert is screwed, for example, into the receiving area so that it is held in a form-fitting manner in the axial direction.

[0009] WO 95 / 016585 A1 discloses a further adjustment device in which a spindle nut is secured in the axial direction by means of bolts passing through the side walls of a holder.

[0010] Based on this, the invention is based on the object of specifying an electrical adjustment device for a longitudinal adjustment of a vehicle seat, in which reliable crash safety is achieved with a cost-effective structural design.

[0011] The object is achieved according to the invention by an electrical adjustment device for a vehicle seat for its longitudinal adjustment with the features of claim 1.

[0012] The adjustment device has a rail system extending in a longitudinal direction, comprising a first rail, hereinafter referred to as the lower rail, and a second rail, hereinafter referred to as the upper rail. Furthermore, the adjustment device has a spindle drive, which includes a spindle and a spindle nut unit. The spindle nut unit has a cage and an insert received therein, which forms a spindle nut that interacts with the spindle. The spindle nut unit is secured in a crash-proof manner via the cage to the first rail, usually via a screw fastening.

[0013] The cage is designed in particular as a metal cage. It has a plurality of side walls extending in the longitudinal direction, namely in particular two lateral side walls, an upper side wall and a lower side wall. Furthermore, the cage has two opposite end faces when viewed in the longitudinal direction. The cage wraps around the insert with the side walls in the circumferential direction, which is oriented transversely to the longitudinal direction. At least one of these side walls and in particular at least one lateral side wall is interlaced with the insert in such a way that a form-fit connection acting in the longitudinal direction is formed between the side wall and the insert. The interlacing between the insert and the at least one side wall of the cage enables a high, in particular crash-safe, force transmission between the insert and the cage.

[0014] Thus, a longitudinally acting positive connection between the insert and the cage is formed via at least one interlocking element on the at least one side wall and at least one corresponding interlocking element on the insert. These interlocking elements are each projections or protrusions projecting transversely to the longitudinal direction, preferably on the insert, and corresponding recesses or openings extending transversely to the longitudinal direction, preferably formed on the at least one side wall.

[0015] The particular advantage of this design is that the force is transmitted via the side walls, which are oriented parallel to the longitudinal direction. Therefore, force transmission does not require transversely oriented structures through which the spindle must pass, which are therefore weakened by the spindle.

[0016] In a preferred embodiment, several side walls, and in particular the two lateral side walls, are interlaced with the insert. This achieves a symmetrical force introduction. Furthermore, the force is distributed across at least two side walls, in contrast to conventional designs, in which only one transverse wall has to absorb the entire force.

[0017] In a useful embodiment, the at least one side wall and the insert each have a plurality of complementary interlocking elements, namely recesses / openings and formations / extensions, which each engage with one another. Complementary interlocking elements are understood here to mean that they are designed to be suitable for force transmission in the longitudinal direction. These preferably fit one another precisely - at least when viewed in the longitudinal direction. Preferably, all side walls that are interlocked with the insert each have interlocking elements. Preferably, the side walls have the recesses and the insert has the formations. By arranging a plurality of interlocking elements on each side wall, a particularly favorable force introduction is achieved.

[0018] In a preferred embodiment, the interlocking elements on at least one side wall are configured differently from one another. Correspondingly, the interlocking elements on the insert are also configured differently. This also optimizes force transmission.

[0019] At least one side wall has an open edge in a partial section, with an edge contour over which the interlocking occurs. An open edge is understood here to be a free end of the side wall (in a direction transverse to the longitudinal direction, specifically in the vertical direction). Therefore, in this partial section, the side wall is not connected to an adjacent side wall over a certain length. The insert engages this edge contour from the opposite side and has protrusions that also form a complementary edge contour, so that the interlocking occurs via the interlocking edge contours.

[0020] Furthermore, the cage's edge contour forms several lobes and recesses between them. The recesses are thus defined by the edge contour, with one side open. The overall edge contour is preferably wave-shaped or stepped. A wave trough / stepped trough forms a recess, and a wave crest / stepped crest forms a lobe.

[0021] Overall, therefore, at least one side wall is provided with a wave-shaped or stepped edge contour in a partial section, which is also referred to as the interlocking section. This creates an overall interlock between the respective side wall of the cage and a corresponding side wall of the insert.

[0022] In a preferred embodiment, the recesses, which are designed like incisions, end at different heights when viewed vertically. The same preferably applies to the tabs. An edge section of one recess or tab that defines the edge contour in the vertical direction is thus arranged at a different height than the corresponding edge section of another recess or tab.

[0023] Alternatively or additionally, the recesses, which are designed like incisions, have different heights in the vertical direction. The same preferably applies to the tabs. This also serves to optimize force transmission.

[0024] The cage is preferably designed as a bent sheet metal cage. The cage is preferably designed as a stamped and bent part, which can be manufactured easily and cost-effectively.

[0025] In a preferred embodiment, the two longitudinally opposite end faces of the cage are open. This means that there are no wall regions on the end faces that extend in the transverse or vertical direction. Therefore, in particular, no bending process about a transverse direction to form a transverse wall perpendicular to the longitudinal direction takes place during the formation of the cage. The cage therefore preferably has no wall regions or wall surfaces oriented transversely to the longitudinal direction. The edges of the side walls, over which the interlacing takes place, are not such wall regions or wall surfaces extending in the transverse direction.

[0026] Overall, in a preferred embodiment, a positive connection between the cage and the insert is formed exclusively via the side walls. These, in particular, do not have any wall sections that protrude in the transverse direction.

[0027] Conveniently, the lower side wall of the cage is interrupted and forms an opening, which is designed in particular as an insertion opening into which the insert can be inserted into the cage from below. The opening extends across the entire width of the lower side wall. Preferably, the insert has a length that corresponds at most to the length of the opening in the longitudinal direction. Preferably, the length of the opening corresponds to the length of the insert in the longitudinal direction.

[0028] To secure the cage to the first rail, the cage preferably has fastening tabs on the lower side wall. In particular, the lower side wall forms two longitudinally opposing fastening tabs. The aforementioned opening is formed between these. The fastening tabs serve for fastening to the first rail and usually lie flat on this first rail. They have, for example, fastening holes, in particular threaded holes for screw fastening.

[0029] In a practical embodiment, the two rails generally enclose a space in which the cage is accommodated with a precise fit, at least in the transverse direction, apart from the necessary play. For this purpose, the cage preferably rests with its lower side wall on the first rail. With its two lateral side walls, it rests against the second rail, apart from the aforementioned play. The two rails usually engage with each other in a form-fitting manner, with their edges being suitably shaped and interlocked. The cage as a whole is inserted with a precise fit into the space between the two rails, apart from the necessary play specifically for relative movement. At the same time, the insert fits snugly in the cage. This achieves good stability overall.

[0030] An embodiment of the invention is explained in more detail below with reference to the figures. These show Fig. 1 a perspective, partial view of an electric adjustment device for longitudinal adjustment of a vehicle seat with an electric spindle drive, Fig. 2 an exploded view of a spindle nut unit with spindle inserted and Fig. 3 a cross-sectional view through a rail system with spindle nut unit and with spindle passed through.

[0031] One in Fig. The adjusting device 2 shown in Figure 1 is used for the longitudinal adjustment of a vehicle seat of a vehicle, in particular a road vehicle, especially a passenger car. The adjusting device 2 usually has two spaced-apart rail systems 4, each extending in the longitudinal direction L. In Fig. 1 shows only one of the rail systems 4. Each rail system 4 has a first rail configured as a lower rail 6 and a second rail configured as an upper rail 8. For longitudinal adjustment of the vehicle seat, the adjustment device 2 further comprises an electric spindle drive 10, which has a spindle 12 extending within the rail system 4 and a spindle nut unit 14 also arranged within the rail system 4. This, in turn, has an insert 16 forming a spindle nut and a cage 18 encompassing the spindle nut.

[0032] In the illustrated embodiment, the spindle nut unit 14 is firmly connected to the lower rail 6 via the cage 18. For longitudinal adjustment, the spindle 12 is driven by an electric motor to rotate about a spindle axis. Through interaction with the spindle nut formed by the insert 16, the rotational movement is converted into a longitudinal movement, which is transmitted to the upper rail 8. A vehicle seat (not shown in detail here) is attached to the upper rail 8 via flanges 20.

[0033] For the electric drive, in the exemplary embodiment, an electric motor 22 is connected via an output shaft, in particular designed as a flexible shaft, to a gear 24, which is coupled to the spindle 12. The spindle 12 is rotatably mounted in bearing points 26. The electric motor 22 is accommodated in a carrier 28, in particular made of plastic, which is usually attached to a front side of the vehicle seat between the usually two opposing rail systems 4. The electric motor 22, the output shaft and the gear 24, together with the carrier 28, form a motor-gear unit, which is firmly connected to the upper rail 8 and therefore moves with it during a longitudinal adjustment.

[0034] The spindle nut unit 14 and thus also the cage 18 each extend in the longitudinal direction L (oriented towards a vehicle front), a transverse direction Q oriented perpendicular thereto and a vertical direction V oriented perpendicular to the longitudinal direction L and the transverse direction Q. The vertical direction V extends upwards, i.e. starting from the lower rail 6 in the direction of the upper rail 8 or in the direction of the vehicle seat.

[0035] The spindle drive 10 must be designed to be crash-proof overall. Particularly critical here is the force acting in or against the longitudinal direction L, which must be reliably transmitted via the spindle 12 to the insert 16 and via the cage 18 and the lower rail 6 to the supporting body.

[0036] For this required force transmission, the cage 18 and the insert 16 are specially designed and, in particular, interlocked with one another. Key to this are the side walls 30 of the cage 18, which each extend in the longitudinal direction L and with which the insert 16 is wrapped in a circumferential direction transverse to the longitudinal direction L.

[0037] The interlocking creates a positive connection that acts in or against the longitudinal direction L. It should be emphasized that the interlocking creates a toothing between at least some of the side walls 30 of the cage 18 and the insert 16. The cage 18 preferably has no transverse walls on its opposite end faces 31 in the longitudinal direction L, and is therefore open on these opposite end faces 31. The positive connection and thus the force transmission therefore preferably occur exclusively via the side walls 30.

[0038] The structure of the spindle nut unit 14 and its arrangement within the rail system 4 results in particular from the Fig. 2 and from the Fig. 3:

[0039] The insert 16 is preferably formed as a plastic component. It has a thread inside it that interacts with the thread of the spindle 12. The insert 16 therefore forms a spindle nut, and the spindle 12 is guided through the insert 16.

[0040] The cage 18 is preferably designed as a sheet metal cage and in particular as a stamped and bent part. The cage 18 has the previously mentioned side walls 30, namely two opposing lateral side walls 30A, an upper side wall 30B, and a lower side wall 30C. The two opposing lateral side walls 30A preferably each extend within a vertical plane spanned by the vertical direction V and the longitudinal direction L. The upper side wall 30B and the lower side wall 30C preferably each extend within a horizontal plane spanned by the transverse direction Q and the longitudinal direction L.

[0041] As can be seen in particular from the Fig. 2, a respective lateral side wall 30A ends - in a defined longitudinal section and viewed counter to the vertical direction V - at a free edge, i.e., is not connected to the lower side wall 30C via the longitudinal section. This free edge forms a special edge contour 32, through which recesses 34 and tabs 36 are formed on a respective lateral side wall 30A. The tabs 36 are formed by partial sections of the lateral side walls 30A, which protrude freely counter to the vertical direction V. The different recesses 34 and tabs 36 form interlocking elements that interact with corresponding interlocking elements on the insert 16.

[0042] The insert 16 has a corresponding edge contour 32', through which a plurality of formations 34' are formed complementary to the recesses 34, which thus form corresponding and complementary interlocking elements to the recesses 34 and engage in them in a form-fitting manner.

[0043] Corresponding to the tabs 36 on the cage 18, the insert 16 has indentations 36'.

[0044] Overall, the insert 16 is characterized in that it is widened in the transverse direction Q in the lower portion oriented toward the lower rail 6, preferably by exactly twice the wall thickness of the cage 18. In a preferred embodiment, the mutually complementary interlocking elements 34, 34' are aligned with one another on the lateral outer sides of the spindle nut unit 14 when inserted.

[0045] The recesses 34 on the cage 18 are designed differently from one another. The same applies to the tabs 36.

[0046] In particular, the recesses 34 are delimited at the top by an edge portion, viewed in the vertical direction 4. The edge portions of the various recesses 34 are arranged at different heights, viewed in the vertical direction V, i.e., the upper boundaries of the recesses 34 are offset from one another.

[0047] Alternatively or additionally, the recesses 34 have a different height in the vertical direction V.

[0048] Alternatively or additionally, the recesses 34 have a different width in the longitudinal direction L.

[0049] Due to the complementary design of the insert 16, this also applies correspondingly to the complementary formations 34' and indentations 36' on the insert 16.

[0050] During assembly, the insert 16 is inserted from below into the interior of the cage 18 in the vertical direction V through an opening 38 formed in the lower side wall 30B. Due to the special edge contours 32, 32', an interlocking in the manner of a toothing is automatically formed between the cage 18 and the insert 16.

[0051] The lower side wall 30C is therefore interrupted by the opening 38. The lower side wall 30C is formed by two opposing fastening tabs 40, each of which has fastening holes 42 provided therein, into which a fastening element 44, for example a screw or a rivet, engages for fastening to the lower rail 6. In the case of a screw connection, the fastening holes 42 are designed, for example, as threaded holes and have an internal thread. In the fastened state, the fastening tabs 40 lie flat on the lower rail 6.

[0052] Overall, the insert 16 has a length in the longitudinal direction L that preferably corresponds exactly to the length of the opening 38. In the inserted state, the insert 16 is held in a form-fitting manner by edge portions of the fastening tabs 40. The height of the insert 16 is therefore suitably selected. In particular, an underside of the insert 16 is aligned with an underside of the lower side wall 30C. In the mounted position, the insert 16 preferably lies flat on the lower rail 6.

[0053] In the exemplary embodiment, the upper side wall 30B also has fastening holes 42 into which fixing elements 46 engage in the assembled state. As can be seen specifically from the Fig. 3, in a preferred embodiment these interact with the insert 16 and fix it.

[0054] As can be seen from the cross-sectional view of the Fig.3, the cage 18 wraps around the insert 16 with the side walls 30, so that the side walls 30, especially the lateral side walls 30A, lie flat against the corresponding wall sections of the insert 16 and form the desired interlacing via the edge contour 32.

[0055] It can also be seen that the lower rail 6 and the upper rail 8 each have specially shaped lateral edge contours that interlock mutually, so that the two rails 6, 8 interlock positively in the vertical direction V. In the exemplary embodiment, a gap 48 is formed between the two rails 6, 8, in which gap the spindle nut unit 14 is received. In the transverse direction Q, the spindle nut unit 14 preferably lies precisely in this gap 48 except for a necessary play. The lateral side walls 30A are each arranged opposite corresponding side walls of the upper rail 8 and preferably have only a tolerance gap thereto in order to enable the necessary relative displacement between the upper rail 8 and the spindle nut unit 14 fastened to the lower rail 6.

[0056] Overall, the spindle nut unit 14 described here with the special design of the cage 18 and the insert 16 with their mutual interlocking / toothing exclusively via the side walls 30 achieves a cost-effective and easy-to-manufacture construction which is designed to absorb high forces and thus ensures high crash safety. List of reference symbols 2 adjustment device 4 rail systems 6 Bottom rail 8 top rail 10 Spindle drive 12 spindle 14 Spindle nut unit 16 deployment 18 cage 20 flange 22 electric motor 24 gearboxes 26 storage location 28 carriers 30 side walls 30A side wall 30B upper side wall 30C lower side wall 31 Front side 32 Edge contour of the cage 32' edge contour of the insert 34 Recess 34' Formation 36 lobes 36' indentation 38 Opening 40 fastening tab 42 mounting hole 44 Fastening element 46 fixing elements 48 space L longitudinal direction Q transverse direction V Vertical direction

Claims

[1] Adjusting device (2) for a vehicle seat with a rail system (4) extending in a longitudinal direction (L) with a first rail (6) and a second rail (8) and with a spindle drive (10) which has a spindle (12) and a spindle nut unit (14), wherein the spindle nut unit (14) has a holder and an insert (16) received therein, which forms a spindle nut, wherein the holder is fastened to the first rail (6), wherein the holder is designed as a cage (18) which has a plurality of side walls (30, 30A, 30B, 30C) extending in the longitudinal direction (L), namely in particular two lateral side walls (30A), an upper side wall (30B) and a lower side wall (30C), wherein the cage (18) with the side walls (30, 30A, 30B, 30C) wraps around the insert (16), and that at least one of the side walls (30, 30A, 30B, 30C) is interlaced with the insert (16),such that a form-fit connection acting in the longitudinal direction (L) is formed between the at least one side wall (30, 30A, 30B, 30C) and the insert (16), and wherein the at least one side wall (30, 30A, 30B, 30C) has an open edge in a partial section, which forms an edge contour (32) via which the interlacing takes place and the edge contour (32) forms a plurality of recesses (34) as interlacing elements and tabs (36) located therebetween. [2] Adjusting device (2) according to the preceding claim, characterized by that several side walls (30, 30A, 30B, 30C), in particular the two lateral side walls (30A) are interlaced with the insert (16). [3] Adjusting device (2) according to one of the preceding claims, characterized by that the at least one side wall (30, 30A, 30B, 30C) and the insert (16) each have a plurality of mutually complementary interlocking elements (34, 34') which each engage with one another. [4] Adjusting device (2) according to the preceding claim, characterized by that the interlocking elements (34, 34') on the at least one side wall (30, 30A, 30B, 30C) are designed differently from one another. [5] Adjusting device (2) according to one of the preceding claims, characterized by that the edge contour (32) is wave-shaped or step-shaped. [6] Adjusting device (2) according to one of the preceding claims, characterized by that the recesses (34) end at different heights when viewed in the vertical direction (V). [7] Adjusting device (2) according to one of the preceding claims, characterized by that the recesses (34) have different heights. [8] Adjusting device (2) according to one of the preceding claims, characterized by that the cage (18) is designed as a sheet metal bent cage. [9] Adjusting device (2) according to one of the preceding claims, characterized bythat the cage (18) has two opposite end faces (31) in the longitudinal direction (L) which are open. [10] Adjusting device (2) according to one of the preceding claims, characterized by that an interlacing between the cage (18) and the insert (16) takes place exclusively via the side walls (30, 30A, 30B, 30C). [11] Adjusting device (2) according to one of the preceding claims, characterized by that the lower side wall (30C) of the cage (18) is interrupted and has an opening (38) into which the insert (16) can be inserted into the cage (18) from below. [12] Adjusting device (2) according to one of the preceding claims, characterized by that fastening tabs (40) are formed on the lower side wall (30C) for fastening the cage (18) to the first rail (6). [13] Adjusting device (2) according to one of the preceding claims, characterized bythat the two rails (6, 8) enclose a space (48) in which the cage (18) is accommodated in the transverse direction (Q) with a precise fit, except for a required play

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