LENGTH ADJUSTER AND VEHICLE SEAT

Abstract

Longitudinal adjuster (10), in particular for a vehicle seat (1), the longitudinal adjuster (10) comprising at least one pair of rails, which is formed from a first rail (12) and a second rail (14) displaceable in the longitudinal direction (x) relative to the first rail (12), wherein the rails (12, 14) mutually engage each other, forming an inner channel (16), wherein a spindle nut (30) mounted on the second rail (14) and a spindle (20) operatively connected to the spindle nut (30) are arranged in the inner channel (16), wherein a spindle drive (50) which can be driven by a motor (60) and which interacts with the spindle (20) is arranged in an end region of the first rail (12), wherein the spindle drive (50) is enclosed by a gearbox housing (52), wherein the gearbox housing (52) has at least one cylindrical bearing section (52b) for mounting a spindle connected to the spindle (20). worm gear (50a)wherein the gearbox housing (52) has a step (52a) adjacent to the cylindrical bearing section (52b), characterized in that the step (52a) is configured to support the worm gear (50a) at its end face coaxially to a spindle axis of the spindle (20) in a crash, wherein the gearbox housing (52) has a recess (52c) in the cylindrical bearing section (52b), wherein a worm gear (50a) screwed onto the spindle (20) is supported in the gearbox housing (52) by means of two bearing sleeves (56) and each bearing sleeve (56) has a projection (56b) which interacts with a recess (52c) of the gearbox housing (52).

Description

LENGTH ADJUSTER AND VEHICLE SEAT The invention relates to a longitudinal adjuster, in particular for a vehicle seat, comprising at least one pair of rails, each consisting of a first rail and a second rail which is longitudinally displaceable relative to the first rail, wherein the rails mutually engage each other, forming an inner channel, wherein a spindle nut mounted on the second rail and a spindle operatively connected to the spindle nut are arranged in the inner channel, wherein a spindle drive, which can be driven by a motor and interacts with the spindle, is arranged in an end region of the first rail, wherein the spindle drive is enclosed by a gearbox housing, and wherein the gearbox housing has at least one cylindrical bearing section for mounting a worm gear connected to the spindle. The invention further relates to a vehicle seat. State of the art A generic drive device for a motor vehicle seat in a sliding device is known from DE 10 2005 023 095 A1. The drive device for use with a motor vehicle seat sliding device comprises matching fixed and movable rail sections that can be moved between a forward and a rearward position. The drive device includes a spindle, a spindle nut, a gearbox, and a mounting device. The spindle defines a spindle axis and has a longitudinally extending spindle thread. The spindle nut can be securely fastened to a first rail section and has an internal thread that can engage with the spindle thread. The gearbox can be mounted on a different rail section and selectively rotates the spindle about the spindle axis.The spindle of the drive device is provided with a spindle wheel which, when the drive device is mounted, extends outwards through spindle wheel openings in the movable rail section. An alternative embodiment of such a drive device is known from DE 10 2013 207 665 A1. US Patent 8,061,756 B2 discloses an electrically operated seat sliding device comprising a lower rail attached to the floor of a vehicle body and an upper rail slidably mounted on the lower rail. A seat is connected to the upper rail. A screw shaft is arranged within the upper rail. A nut is screwed to the screw shaft and connected to the lower rail. A motor is located on the side of the upper rail. A gearbox is attached to the upper rail to transmit rotation of the motor to the screw shaft. From DE 10 2006 000 195 A1, a motor-driven adjustment mechanism for a vehicle seat is known, comprising a first rail for attachment to a vehicle floor and a second rail for attachment to the vehicle seat. The second rail is slidably supported relative to the first rail. The adjustment mechanism further comprises a threaded shaft screwed to a nut element, the nut element being provided on the first rail. The threaded shaft has a stepped section and a section with a smaller diameter. The adjustment mechanism also includes a disc engaging with the stepped section of the threaded shaft, a fastening element provided on the section with the smaller diameter, and a gearbox provided on the second rail. From DE 10 2005 001 333 A1, a gearbox for an adjustment device for a vehicle seat is known. Inside a gearbox housing, a spindle nut, which sits on a spindle, is arranged between two bearing bushings. To reduce noise, these bearing bushings have a guide section for guiding the spindle nut and a guide section for guiding the threaded spindle. For this purpose, for example, a cylindrical bearing section of the bearing bushings is equipped with a changing inner diameter. From DE 10 2006 011 718 A1, an adjusting device is known which has a gearbox which is attached to a first guide rail via a retaining bracket, wherein the gearbox protrudes through an opening in the first guide rail with a pin-like protrusion and the retaining bracket is flanged to the first guide rail. From DE 11 2019 000 026 T5, an adjustment device for a vehicle seat is known, comprising a housing, a worm, a worm wheel, and a spindle. The worm is arranged for rotation about a first axis within the housing and comprises a helical thread. The worm wheel is arranged for rotation about a second axis within the housing and meshes with the worm. The spindle extends through the housing and the worm wheel for rotation about the second axis. The spindle meshes with the worm wheel. Task The invention is based on the objective of improving a longitudinal adjuster of the type mentioned above, in particular a longitudinal adjuster with a spindle drive which enables increased stiffness and load-bearing capacity, as well as providing a corresponding vehicle seat. Solution This problem is solved according to the invention by a longitudinal adjuster, in particular for a vehicle seat, the longitudinal adjuster comprising at least one pair of rails, which is formed from a first rail and a second rail which is longitudinally displaceable relative to the first rail, wherein the rails mutually engage each other, forming an inner channel, wherein a spindle nut mounted on the second rail and a spindle operatively connected to the spindle nut are arranged in the inner channel, wherein a spindle drive which can be driven by a motor and which interacts with the spindle is arranged in an end region of the first rail, wherein the spindle drive is enclosed by a gearbox housing, wherein the gearbox housing has at least one cylindrical bearing section for mounting a worm gear connected to the spindle, wherein the gearbox housing has a step adjacent to the cylindrical bearing section.the step is designed to support the worm gear in the event of a crash. The gearbox housing features a step adjacent to the cylindrical bearing section, reinforcing it and enabling it to withstand increased axial loads along the spindle and transfer these loads via the spindle holder. Furthermore, the step's design, which supports the worm gear in a crash, provides an additional axial contact or support surface within the gearbox housing, allowing the worm gear to bear against this surface in the event of a collision. Advantageous embodiments, which can be used individually or in combination with each other, are the subject of the dependent claims. The first rail is preferably a seat rail connectable to a vehicle seat. The second rail is preferably a floor rail connectable to a vehicle structure. A possible internal structure as well as the mode of operation and function of the spindle drive is known, for example, from DE 10 2013 207 665 A1, the relevant disclosure content of which is hereby expressly incorporated. The gearbox housing can be formed by several housing parts, in particular two housing parts. Furthermore, a gearbox holder can be provided, which encompasses the gearbox housing and by means of which the spindle drive is connected to the first rail. The spindle can be inserted through two mutually parallel legs of a substantially U-shaped gearbox holder. The two opposing legs are preferably connected to each other by a web in a manner known per se. Alternatively, the two legs can be without a web, i.e., without any connection to each other. Each leg can be connected to a mounting leg, by means of which the gearbox holder is attached to the upper rail. The mounting legs are preferably bent or angled at approximately 90° relative to their respective legs. In the assembled state of the essentially U-shaped gearbox holder, the gearbox housing is preferably accommodated longitudinally x between the legs. The mounting legs may have threaded holes by means of which, in interaction with appropriate screws and / or threaded bolts, a connection to the first rail can be established. In a crash, the worm gear can be supported coaxially to a spindle axis by means of the step. A step can be arranged on opposite outer sides of the gearbox housing, parallel to a spindle axis. The gearbox housing can have a cylindrical bearing section adjacent to each step. The at least one step can project radially inwards relative to the cylindrical bearing section. The inner diameter of the step can be smaller than the inner diameter of the cylindrical bearing section. The gearbox housing has a recess in the cylindrical bearing section, preferably in an upper section of the cylindrical bearing section. A worm gear screwed onto the spindle is mounted in the gearbox housing by means of two bearing sleeves. The bearing sleeves may each have a collar. Each bearing sleeve has a projection that interacts with the recess in the gearbox housing. By means of the projection of the bearing sleeve in conjunction with the recess in the gearbox housing, an anti-rotation device for the bearing sleeve can be provided. The bearing sleeves can be mounted in the gearbox housing in such a way as to prevent rotation. The problem is further solved according to the invention by a vehicle seat with a longitudinal adjuster described above. Figures and embodiments of the invention The invention is explained in more detail below with reference to an advantageous embodiment illustrated in the figures. However, the invention is not limited to this embodiment. The figures show: Fig. 1: a vehicle seat according to the invention, Fig. 2: a longitudinal adjuster according to the invention, Fig. 3: a side view of a pair of rails of the longitudinal adjuster from Fig. 2, with a first rail cut in one plane, Fig. 4: a partial longitudinal section through the pair of rails from Fig. 3 in the area of ​​a transmission mount, Fig. 5: schematically a first half of a transmission housing, Fig. 6: a perspective view of the first half of the transmission housing from Fig. 5, Fig. 7: schematically the first half of the transmission housing from Fig. 5 with the transmission inserted, and Fig. 8: a partial perspective view of the first half of the transmission housing with the transmission from Fig. 7 inserted. A vehicle seat 1, schematically depicted in Fig. 1, is described below using three mutually perpendicular spatial directions. A longitudinal direction x of a vehicle seat 1 installed in a vehicle runs largely horizontally and preferably parallel to a longitudinal direction of the vehicle, which corresponds to the vehicle's usual direction of travel. A transverse direction y, perpendicular to the longitudinal direction x, is also horizontally oriented in the vehicle and runs parallel to a transverse direction of the vehicle. A vertical direction z runs perpendicular to the longitudinal direction x and perpendicular to the transverse direction y. In a vehicle seat 1 installed in a vehicle, the vertical direction z runs parallel to the vehicle's vertical axis. The position and direction designations used, such as front, rear, top, and bottom, refer to the viewing direction of an occupant seated in vehicle seat 1 in a normal seating position, where the vehicle seat 1 is installed in the vehicle in a suitable position for passenger transport with the backrest 4 upright and oriented in the direction of travel as usual. However, the vehicle seat 1 can also be installed in a different orientation, for example, perpendicular to the direction of travel. The vehicle seat 1 for a motor vehicle shown in Fig. 1 has a seat section 2 and a backrest 4 whose inclination is adjustable relative to the seat section 2. The inclination of the backrest 4 can be adjusted, for example, by means of a ratchet fitting or a geared fitting. The vehicle seat 1 is mounted on a longitudinal adjuster 10 for setting the seat's longitudinal position. Fig. 2 shows an example of a longitudinal adjuster 10 according to the invention for a vehicle seat 1. The longitudinal adjuster 10 has at least one pair of rails, in this case two pairs of rails. The pairs of rails each consist of a first rail 12, in particular for connection to a seat structure of the vehicle seat 1, and a second rail 14, in particular for connection to a vehicle structure. The rails 12, 14 of the pair of rails are displaceable relative to each other in the longitudinal direction x and mutually engage each other, forming an inner channel 16. In the inner channel 16, a spindle nut 30, rigidly connected to the second rail 14, and a spindle 20, operatively connected to the spindle nut 30, are arranged. The spindle 20 extends along a spindle axis parallel to the longitudinal direction x. At a front end of the first rail 12, a spindle drive 50, driven by a motor 60, is arranged. The spindle 20 is driven by the spindle drive 50. The motor 60 is held on a motor bracket 70 mounted between the two spindle drives 50 of the respective rail pairs and drives the two spindle drives 50 by means of a shaft (not shown in Fig. 2). Fig. 3 shows a side view of a pair of rails of the longitudinal adjuster 10 with the first rail 12 cut away in a first plane. The spindle 20 is rotatably mounted in the region of a rear end section 20b of the spindle 20 by means of a spindle holder. The spindle holder is designed as a rotary bearing 40 and is held on the first rail 12. In the region of a front end section 20a of the spindle 20, a spindle drive 50 is arranged for the rotary drive of the spindle 20. This drive is held in a gear holder 54, which is fixedly connected to the first rail 12. Fig. 4 shows a partial longitudinal section through the pair of rails from Fig. 3, in the area of ​​the gear holder 54. A gear housing 52 is provided to support the individual gear elements of the spindle drive 50. This housing, acting as a load-bearing structure, fills the space defined between the gear holder 54 and the first rail 12 with maximum rigidity, essentially within the first rail 12. The gear housing 52 consists of two side panels that partially abut each other and are bolted together. The two side panels support a drive worm 50b arranged transversely to the longitudinal direction x of the first rail 12. The drive worm 50b is operatively connected to a worm gear 50a, which is mounted longitudinally x. The worm gear 50a is rotationally fixed to the spindle 20. In this case, the worm gear 50a, which has an internal thread section 58, is screwed onto an external thread of the spindle 20 in the front end section 20a and secured by a locking element 34. The locking element 34 is pressed into the front end section 20a of the spindle 20 between the spindle 20 and the worm gear 50a. The longitudinal adjuster 10 provides a press fit or crimp connection for a rotationally fixed connection between a front end section 20a of the spindle 20 and the worm gear 50a. In this connection, one or more locking elements 34 are pressed together by partially sliding them between the front end section 20a, which projects forward from the worm gear 50a, and a similarly forward-oriented section of the worm gear 50a. These locking elements 34 are preferably annular or hollow cylindrical in shape and are arranged on the threadless front end section 20a of the spindle 20. The gear holder 54, which encloses the gear housing 52 and by means of which the spindle drive 50 is connected to the first rail 12, is essentially U-shaped. The spindle 20 is inserted through two parallel legs 54b of the gear holder 54. The two opposing legs 54b are preferably connected to each other by a web 54a in a manner known per se. A mounting leg 54c adjoins each leg 54b, by means of which the gear holder 54 is attached to the first rail 12. The mounting legs 54c are further preferably bent or angled by approximately 90° relative to their respective legs 54b, in this case each bent in a direction away from the spindle drive 50. In the assembled state of the essentially U-shaped gear holder 54, the gear housing 52 is preferably received in the longitudinal direction x between the legs 54b. The mounting legs 54c have threaded bores by means of which a connection to the first rail 12 is established by means of corresponding screws and / or threaded bolts. Figures 5, 6, 7 to 8 show parts of the spindle drive 50 with the gearbox housing 52 open, and are described together below. The spindle drive 50 is enclosed by the gearbox housing 52. The gearbox housing 52 has two cylindrical bearing sections 52b for supporting the worm gear 50a connected to the spindle 20. The gearbox housing 52 has a step 52a adjacent to each of the cylindrical bearing sections 52b, the step 52a being designed to support the worm gear 50a in the event of a crash. Parallel to an axis of the spindle 20, a step 52a is arranged on opposite outer sides of the gearbox housing 52. The steps 52a project radially inwards relative to the cylindrical bearing section 52b. The inner diameter d1 of the steps 52a is smaller than the inner diameter d2 of the cylindrical bearing sections 52b. The gearbox housing 52 has a recess 52c in an upper section of the cylindrical bearing section 52b. A worm gear 50a, screwed onto the spindle 20, is mounted in the gearbox housing 52 by means of two bearing sleeves 56. Each bearing sleeve 56 has a collar 56a. Each bearing sleeve 56 has a projection 56b which engages with the recess 52c of the gearbox housing 52. The bearing sleeves 56 are secured against rotation in the gearbox housing 52. In a crash, particularly a frontal or rear-end collision, the first rail 12 and second rail 14 are subjected to longitudinal forces relative to each other in the x-direction due to the crash. A force impulse introduced into the first rail 12 from the vehicle seat 1 must be transmitted to the vehicle via the gearbox mount 54, the spindle drive 50, the spindle 20, and the second rail 14, or vice versa. Such a load on the longitudinal adjuster 10 can lead to a comparatively very high load on the worm gear 50a in the x-direction. The radially inwardly projecting steps 52a of the gearbox housing 52 provide the worm gear 50a with additional support surfaces in the axial direction, or in this case, parallel to the x-direction. These surfaces allow the gearbox housing 52 to better absorb the load on the worm gear 50a in the x-direction and transmit it to the gearbox mount 54. The features disclosed in the foregoing description, claims and drawings may be important, both individually and in combination, for the realization of the invention in its various embodiments, insofar as this is covered by the wording of the independent claims. Reference symbol list 1 Vehicle seat 2 Seat section 4 Backrest 10 Longitudinal adjuster 12 First rail 14 Second rail 16 Inner channel 20 Spindle 20a Front end section (of spindle 20) 20b Rear end section (of spindle 20) 30 Spindle nut 34 Locking element 40 Swivel bearing 50 Spindle gear 50a Worm gear 50b Drive worm 52 Gearbox housing 52a Stage 52b Cylindrical bearing section 52c Recess 54 Gearbox holder 54a Web 54b Leg 54c Mounting leg 56 Bearing sleeve 56a Collar 56b Projection 58 Internal thread section 60 Motor 70 Motor mount d1 Inner diameter d2 Inner diameter x Longitudinal direction y Transverse direction z Vertical direction

Claims

Longitudinal adjuster (10), in particular for a vehicle seat (1), the longitudinal adjuster (10) comprising at least one pair of rails, which is formed from a first rail (12) and a second rail (14) displaceable in the longitudinal direction (x) relative to the first rail (12), wherein the rails (12, 14) mutually engage each other, forming an inner channel (16), wherein a spindle nut (30) mounted on the second rail (14) and a spindle (20) operatively connected to the spindle nut (30) are arranged in the inner channel (16), wherein a spindle drive (50) which can be driven by a motor (60) and which interacts with the spindle (20) is arranged in an end region of the first rail (12), wherein the spindle drive (50) is enclosed by a gearbox housing (52), wherein the gearbox housing (52) has at least one cylindrical bearing section (52b) for supporting a spindle connected to the spindle (20). worm gear (50a)wherein the gearbox housing (52) has a step (52a) adjacent to the cylindrical bearing section (52b), characterized in that the step (52a) is configured to support the worm gear (50a) at its end face coaxially to a spindle axis of the spindle (20) in a crash, wherein the gearbox housing (52) has a recess (52c) in the cylindrical bearing section (52b), wherein a worm gear (50a) screwed onto the spindle (20) is supported in the gearbox housing (52) by means of two bearing sleeves (56), and each bearing sleeve (56) has a projection (56b) which interacts with a recess (52c) of the gearbox housing (52). Longitudinal adjuster (10) according to claim 1, wherein a step (52a) is arranged on each of the outer sides of the gearbox housing (52) opposite an axis of the spindle (20). Longitudinal adjuster (10) according to one of claims 1 to 2, wherein the step (52a) projects radially inwards relative to the cylindrical bearing section (52b). Longitudinal adjuster (10) according to one of claims 1 to 3, wherein an inner diameter (d1) of the step (52a) is smaller than an inner diameter (d2) of the cylindrical bearing section (52b). Longitudinal adjuster (10) according to one of claims 1 to 4, wherein the bearing sleeves (56) each have a collar (56a). Vehicle seat (1) with a longitudinal adjuster (10) according to one of claims 1 to 5.

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