Gearbox arrangement, longitudinal adjuster and vehicle seat

Abstract

Gear arrangement (10) comprising: - a case (13), - a gearbox (17), - a drive (15) with a drive element (16) for the gearbox (17), and - a drive (18) coupled to the drive (15) via the gearbox (17) with an interface (19) to a spindle nut (12) for a spindle (11) or to a spindle (11) for direct coupling with the spindle (11), wherein the drive (15) has a drive axis (20) and the spindle nut (12) or spindle (11) has a rotation axis (21), wherein the drive axis (20) is identical to the rotation axis (21) and both form a central rotation axis (22), wherein the gearbox (17) is arranged concentrically to the central axis of rotation (22) and serves as the output (18), and wherein the transmission (17) has an outer ring (24) and an elastic transmission element (25) with a bearing (26) and a central transmission axis which is identical to the central axis of rotation (22), and wherein the gear assembly (10) with the drive (15), the gear (17) and the spindle nut (12) is arranged in the housing (13) and wherein the spindle nut (12) is rotatably mounted in the housing (13) via a further bearing (28).

Description

[0001] The invention relates to a gear arrangement for a longitudinal adjuster for a vehicle seat, in particular a motor vehicle seat, as well as a longitudinal adjuster with such a gear arrangement and a vehicle seat.

[0002] An exemplary longitudinal adjustment device for vehicle seats is known from DE 298 14 626 U1. In this device, a drive torque from a motor is transmitted via a drive unit through a shaft running transversely to the two pairs of rails. The motor is typically located between the two pairs of rails. The shaft is located in an area below the center of the vehicle seat, running transversely to the two pairs of rails. The shaft is associated with the two seat rails, so that the shaft and the motor do not change their positions relative to the seat frame, but they do change their positions relative to the floor rails.

[0003] Such a design requires sufficient installation space beneath the seat. This space may be needed for future developments of the vehicle seat or the vehicle itself. For example, in electrically powered vehicles, this space may be required in the future to house batteries and / or accumulators.

[0004] In the prior art, DE 198 60 910 B4 discloses a drive for a longitudinal adjuster of a vehicle seat, in which the longitudinal adjuster has two pairs of rails, each with a drive motor, wherein the two drive motors are arranged projecting into a space between the respective pair of rails.

[0005] From EP 3 358 218 A2, an adjustment device with a drive is known which is coupled to a spindle via a gearbox, wherein the gearbox is designed as a planetary gearbox or helical planetary gearbox.

[0006] The invention is based on the objective of improving the efficiency of a gear arrangement for a longitudinal adjuster in order to enable the use of small, cost-effective motors, as well as providing a longitudinal adjuster with such a gear arrangement and a corresponding vehicle seat with a longitudinal adjuster with such a gear arrangement.

[0007] With regard to the transmission arrangement, the problem is solved according to the invention by the features of claim 1, with regard to the longitudinal adjuster for a vehicle seat by the features of claim 5 and with regard to the vehicle seat by the features of claim 11.

[0008] With regard to the gearbox arrangement, the problem is solved according to the invention by at least one housing which has at least one drive with a drive element, in particular with one or more drive pins or bearing pins, for a gearbox and an output coupled to the drive via the gearbox with an interface to a spindle nut for a spindle or to a spindle for direct coupling with the spindle, wherein the drive has a drive axis and the spindle nut or spindle has a rotation axis, wherein the drive axis is identical to the rotation axis and form a central rotation axis and the gearbox is arranged concentrically to the central rotation axis.

[0009] In one possible embodiment, the transmission is a wave gear or a stress wave gear, in particular a so-called harmonic drive, which comprises a so-called wave generator, which includes, for example, a fixed outer ring, an elastic transmission element, for example, an elliptical sleeve, and a bearing, wherein the sleeve has a central drive axis and an elliptically deformable ball bearing or roller bearing.

[0010] With regard to the longitudinal adjuster for a vehicle seat, in particular a motor vehicle seat, the problem is solved according to the invention with at least one pair of rails, which has a seat rail connectable to the vehicle seat and a floor rail connectable to a vehicle floor, on which the seat rail is slidably guided along a longitudinal direction, wherein the longitudinal adjuster has a drive device for adjusting the seat rail along the longitudinal direction relative to the floor rail, wherein the drive device comprises an electric motor, the previously described gear arrangement and a spindle fixed to the floor rail or to the seat rail, wherein the electric motor is operatively connected to the spindle via the gear arrangement in order to convert the movement of the spindle into a longitudinal adjustment of the vehicle seat via the spindle nut attached to the floor rail.

[0011] The required self-locking between the spindle nut and the spindle for load transfer in the event of a crash can be achieved by a corresponding, in particular low, pitch of a nut thread of the spindle nut, in particular a trapezoidal thread, for example a trapezoidal thread TR8x2.

[0012] Alternatively, the rotating spindle can be mounted in the bottom rail and the spindle nut on the seat rail.

[0013] The electric motor can be positioned in front of the gearbox assembly. For example, the electric motor can be located entirely within the seat rail or top rail. Alternatively, the electric motor can be located partially or entirely outside the seat rail or top rail. The electric motor and gearbox assembly can be located at the front or rear end of the top rail.

[0014] Such a longitudinal adjuster requires minimal installation space; in particular, the space between the rail pairs is free and can be used, for example, as a battery compartment. Small, cost-effective electric motors, such as 3 Ncm to 8 Ncm at 8,000 to 12,000 revolutions per minute (RPM), can be used.

[0015] In this arrangement, both the electric motor and the gearbox assembly can be at least partially positioned through a recess in a cavity formed between the seat rail and the base rail. The electric motor can be positioned partially within the cavity through the recess in such a way as to achieve the lowest possible overall height, measured from the lower edge of the base rail opposite the electric motor to the upper edge of the electric motor and / or a gearbox housing, or from the upper edge of the seat rail opposite the electric motor to the lower edge of the electric motor and / or a gearbox housing.

[0016] Advantageous embodiments, which can be used individually or in combination with each other, are the subject of the dependent claims.

[0017] Exemplary embodiments of the invention are explained in more detail with reference to the drawings. These show: Fig. 1. In perspective view, an adjustable vehicle seat with a longitudinal adjuster, Fig. 2 in exploded view a drive unit for a longitudinal adjuster, Fig. 3 in exploded view a gear arrangement for a longitudinal adjuster, Fig. 4 in perspective view a gearbox for a gearbox arrangement, Fig. 5 in a sectional view the gear arrangement according to Fig. 3, Fig. 6 in perspective view an end area of ​​a rail pair of a longitudinal adjuster, Fig. 7 in perspective view a pair of rails of a longitudinal adjuster, and Fig. 8 a top view of the end area according to Fig. 6.

[0018] Corresponding parts are marked with the same reference symbols in all figures.

[0019] A in Fig. A schematically represented vehicle seat 1 is described below using three mutually perpendicular spatial directions. A longitudinal direction X, in 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.

[0020] The position and direction specifications used, such as front, rear, top, and bottom, refer to the viewing direction of an occupant seated in a vehicle seat 1 in a normal seating position, wherein the vehicle seat 1 is installed in the vehicle in a suitable position for passenger transport with an upright backrest 2 oriented in the direction of travel, as usual. However, a vehicle seat 1 according to the invention can also be installed in a different orientation, for example, transversely to the direction of travel.

[0021] The vehicle seat 1 has a seat section 3 and a backrest 2 which is adjustable in its inclination relative to the seat section 3 and can be swivelled forwards in the direction of the seat section 3.

[0022] For the longitudinally movable and longitudinally adjustable mounting of the vehicle seat 1 in the vehicle, the vehicle seat 1 has a longitudinal adjuster 4.

[0023] The longitudinal adjuster 4 serves for the longitudinal adjustment, i.e., the setting of a longitudinal seat position, of the vehicle seat 1. For this purpose, the longitudinal adjuster 4 has a pair of rails 5 on each side of the vehicle seat. One pair of rails 5 is located on a tunnel side and the other pair of rails 5 on a sill side of the vehicle. The two pairs of rails 5 of the longitudinal adjuster 4 run parallel to each other. Each pair of rails 5 has a floor rail 6 that can be connected to a vehicle floor and, guided by means of this floor rail, a seat rail 7 that can be connected to the vehicle seat 1.

[0024] The seat rail 7 is guided in a slidable manner relative to the floor rail 6 along the longitudinal direction X.

[0025] The following Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7 to Fig. Figure 8 shows various components of the longitudinal adjuster 4 in detail.

[0026] Fig. Figure 2 shows an exploded view of a drive unit 8 for the longitudinal adjuster 4.

[0027] The drive device 8 for adjusting the seat rail 7 along the longitudinal direction X relative to the floor rail 6 comprises, at least for one of the rail pairs 5, an electric motor 9, a gear arrangement 10 and a spindle 11 fixed to the floor rail 6 or to the seat rail 7, wherein the electric motor 9 is operatively connected to the spindle 11 via the gear arrangement 10 in order to convert the movement of the spindle 11 into a longitudinal adjustment of the vehicle seat 1 via a 12 attached to the floor rail 6.

[0028] The required self-locking between spindle nut 12 and spindle 11 for load transfer in the event of a crash can be achieved by a corresponding, in particular low, pitch of a (not shown) nut thread of the spindle nut 12, in particular a trapezoidal thread, for example a trapezoidal thread TR8x2.

[0029] In an alternative embodiment not shown, the rotating spindle 11 can be mounted in the base rail 6 and the spindle nut 12 on the seat rail 7.

[0030] The electric motor 9 can be positioned in front of the gearbox assembly 10. For example, the electric motor 9 can be arranged at the end face of a housing 13 or cover 14 of the gearbox assembly 10.

[0031] The gear arrangement 10 comprises at least one drive 15 with a drive element 16 for a gearbox 17 and an output 18 coupled to the drive 15 via the gearbox 17, with an output interface 19 to the spindle nut 12 for the spindle 11, wherein the drive 15 has a drive axis 20 and the spindle nut 12 and / or spindle 11 have a rotation axis 21. The drive axis 20 is identical to the rotation axis 21, and together they form a central rotation axis 22. The gearbox 17 is arranged concentrically to the central rotation axis 22.

[0032] To protect these components of the gearbox assembly 10, they are arranged in the housing 13, which is closed by means of the cover 14. Both the housing 13 and the cover 14 have corresponding connection openings 23 for connecting the electric motor 9 and the spindle 11, respectively.

[0033] The electric motor 9 includes, for example, a motor shaft 9.1 for coupling with the drive 15. The drive 15 includes a drive receptacle 15.1 corresponding to the motor shaft 9.1.

[0034] The drive element 16 comprises, for example, one or more bearing journals 16.1. In the exemplary embodiment, two bearing journals 16.1 are shown.

[0035] In one possible embodiment, the transmission 17 is a shaft transmission or a stress wave transmission, in particular a so-called harmonic drive. The transmission 17 is a so-called shaft generator. The transmission 17 comprises, for example, an outer ring 24, in particular a rigid one, and a transmission element 25, in particular an elastic one, for example an elliptical sleeve, with a bearing 26 and the output 18.

[0036] The elastic transmission element 25, in particular a sleeve made of flexible steel or plastic, has a central drive axis 27 and the bearing 26, in particular an elliptically deformable bearing, for example a ball bearing or roller bearing. The central drive axis 27 is identical to the central rotation axis 22 and thus to the drive axis 20 of the electric motor 9 and the rotation axis 21 of the spindle nut 12 and / or the spindle 11.

[0037] The output 18 includes, for example, one or more output pins 18.1 as the output interface 19.

[0038] For the rotatable mounting of the spindle nut 12 in the housing 13, a ball bearing 28 is arranged on each end face of the spindle nut 12. The respective ball bearing 28 is in particular an angular contact ball bearing or a rolling bearing with a tapered bore.

[0039] A clamping ring or clamping sleeve 29 can be provided to securely seat the ball bearings 28 on the cylindrical spindle nut 12. The clamping sleeve 29 is, for example, arranged between the ball bearing 28 pointing towards the electric motor 9 and the output 18 of the gearbox 17. The clamping sleeve 29 can be supported on the outer ring 24 by a ring spring 30, a disc spring, or a Belleville spring. Furthermore, the output 18 can have a corresponding shoulder 18.2 for supporting the clamping sleeve 29.

[0040] For the motion coupling of the output 18 with the spindle nut 12, the latter has an interface 31. The interface 31 corresponds to the output interface 19 of the gearbox 17.

[0041] Instead of coupling the output interface 19 with the interface 31 of the spindle nut 12 for the spindle 11, the output interface 19 can be directly coupled to a face end of the spindle 11 (not shown in detail).

[0042] The drive element 16 is motion-coupled with the electric motor 9 and converts the movement of the electric motor 9 into a movement of the gearbox 17 and via this and the spindle nut 12 into a movement of the spindle 11.

[0043] Fig. Figure 3 shows an exploded view of the gear arrangement 10 for the longitudinal adjuster 4.

[0044] The electric motor 9 drives two bearings 26, for example two ball bearings or roller bearings, which are in contact on the inside with the transmission element 25, in particular a flexible sleeve made of metal or plastic, on which an external toothing 25.1 is arranged.

[0045] This transmission element 25 serves as the output 18. This transmission element 25 is in contact with the rigid outer ring 24, which is connected to the housing 13. The outer ring 24 has internal teeth 24.1. These internal teeth 24.1 have more teeth than the external teeth 25.1.

[0046] The elastic, partially externally toothed transmission element 25, in particular a sleeve, is pressed with its external toothing 25.1 into two opposing areas of the outer ring 24 with the internal toothing 24.1 via the bearings 26, in particular a ball bearing or cylindrical bearing or roller bearing.

[0047] The difference in the number of teeth between the external gearing 25.1 and the internal gearing 24.1 is typically 2, but can vary depending on the desired gear ratio. With each complete rotation of the input 15, the rotation of the output 18 differs by the angle of the corresponding tooth difference. The efficiency of the gearbox 17 is very good at 85%. Approximately 30% of the teeth are engaged for power transmission. For example, if the internal gearing 24.1 had 30 teeth and the external gearing 25.1 had 28 teeth (a tooth difference of 2), the resulting reduction in speed would be i = 28 / 2 = 14.

[0048] The gearbox 17, in particular the harmonic drive, is part of the overall system of the gearbox assembly 10 of the longitudinal adjuster 4, in which the rotating spindle 11, which is mounted to the seat rail 7, implements the longitudinal adjustment of the vehicle seat 1 via the spindle nut 12, which is attached to the lower rail 6. The necessary self-locking between the spindle nut 12 and the spindle 11 for load transfer in the event of a crash is achieved by a low pitch of the trapezoidal thread of the spindle nut 12 and the spindle 11.

[0049] Fig. Figure 4 shows in perspective the gearbox 17 of the gearbox arrangement 10.

[0050] The bearings 26 rotate in the direction of the arrow according to the first arrows P1, each about its bearing axes 32 and about the central axis of rotation 22, driven by the motor 9 via the bearing journals 16.1.

[0051] The elastic transmission element 25, in particular the elastic sleeve, with the external toothing 25.1 located on it, is pressed into the internal toothing 24.1 of the outer ring 24 at opposing areas.

[0052] With each complete rotation of the bearings 26 around the central axis of rotation 22, the spindle 11, which is coupled to the transmission element 25 via the spindle nut 12, rotates in the opposite direction to the drive direction shown by arrow P1, as indicated by a second arrow P2. The angular difference corresponds to the angle of the tooth difference between the outer ring 24 and the inner transmission element 25 (also called the inner ring).

[0053] Fig. Figure 5 shows a lateral sectional view of the gear arrangement 10 according to Fig. 3.

[0054] In a further simplified embodiment of the gear arrangement 10, for example not prefabricated, the elastic transmission element 25 with the output 18 can be directly connected to a front end of the drive spindle 11 by a material bond.

[0055] In another embodiment, the outer ring 24 can be arranged directly in the seat rail 7 and connected to it by a material bond or a force bond. The electric motor 9 is connected to the gearbox 17 via the bearings 26, which deform the sleeve-shaped, elastic transmission element 25.

[0056] Alternatively or additionally, the connection of the electric motor 9 to the gearbox 17 can be achieved via a simple plastic adapter in the seat rail 7 (not shown in detail). The force transmission from spindle 11 to the seat rail 7 must then be accomplished via further separate components.

[0057] Fig. Figure 6 shows in perspective an end area of ​​one of the rail pairs 5 of the longitudinal adjuster 4.

[0058] Fasteners and associated components are not shown.

[0059] The electric motor 9 and the gear assembly 10 are connected via the housing 13, for example a plastic housing.

[0060] The housing 13 can, for example, be connected to the seat rail 7 (e.g., by a material-fit or form-fit connection) in order to transmit high forces. For example, the seat rail 7 can have a recess 7.1 into which the housing 13 is arranged to project at least partially, as shown in Fig. 6 is shown.

[0061] These high forces in the crash are transmitted via the spindle 11 to the spindle nut 12 and via the bearings 26, in particular angular contact ball bearings, directly or via the clamping sleeve 29 to the housing 13, which is firmly connected to the seat rail 7.

[0062] The electric motor 9 can, for example, be arranged completely within the seat rail 7. Alternatively, the electric motor 9 can also be arranged partially or completely outside the seat rail 7. The electric motor 9 and the gear assembly 10 can be arranged at the front end or the rear end of the seat rail 7.

[0063] Fig. Figure 7 shows in perspective the pair of rails 5 with the enclosed gear assembly 10 arranged in the cavity 33 between the seat rail 7 and the floor rail 6.

[0064] Fig. Figure 8 shows a top view of the end area according to Fig. 6. Reference symbol list 1 vehicle seat 2 backrests 3 Seat section 4 longitudinal adjusters 5 pairs of rails 6 floor rail 7 seat rail 7.1 Exclusion 8 Drive unit 9 Electric motor 9.1 Engine pin 10 Gear arrangement 11 Spindle, drive spindle 12 Spindle nut 13 cases 14 lids 15 Drive 15.1 Drive connection 16 Drive element 16.1 Bearing journal 17 gearboxes 18 Drive 18.1 Drive pin Paragraph 18.2 19 Output interface, interface 20 drive axle 21 Rotation axis 22 Central axis of rotation 23 Connection opening 24 outer ring 24.1 Internal gearing 25 Transmission element 25.1 External gearing 26 warehouses 27 Central drive axle 28 ball bearings 29 Tension sleeve 30 ring springs 31 Interface 32 bearing axle 33 Cavity P1, P2 arrows X Longitudinal direction Y transverse direction Z Vertical direction

Claims

[1] Gear arrangement (10) comprising: - a case (13), - a gearbox (17), - a drive (15) with a drive element (16) for the gearbox (17), and - a drive (18) coupled to the drive (15) via the gearbox (17) with an interface (19) to a spindle nut (12) for a spindle (11) or to a spindle (11) for direct coupling with the spindle (11), wherein the drive (15) has a drive axis (20) and the spindle nut (12) or spindle (11) has a rotation axis (21), wherein the drive axis (20) is identical to the rotation axis (21) and both form a central rotation axis (22), wherein the gearbox (17) is arranged concentrically to the central axis of rotation (22) and serves as the output (18), and wherein the transmission (17) has an outer ring (24) and an elastic transmission element (25) with a bearing (26) and a central transmission axis which is identical to the central axis of rotation (22), and wherein the gear assembly (10) with the drive (15), the gear (17) and the spindle nut (12) is arranged in the housing (13) and wherein the spindle nut (12) is rotatably mounted in the housing (13) via a further bearing (28). [2] Gear arrangement (10) according to claim 1, wherein the drive element (16) has one or more drive pins or bearing pins (16.1). [3] Gear arrangement (10) according to claim 1 or 2, wherein the gear (17) is a shaft gear or a tension shaft gear. [4] Gear arrangement (10) according to claim 3, wherein the gear (17) comprises a shaft generator comprising a fixed outer ring (24) as the outer ring (24), an elliptical sleeve as the elastic transmission element (25) and the bearing (26), wherein the sleeve has a central drive axis (27) as the central gear axis and the bearing (26) is an elliptically deformable ball bearing or roller bearing. [5] Longitudinal adjuster (4) for a vehicle seat (1), comprising at least one pair of rails (5) comprising a seat rail (7) connectable to the vehicle seat (1) and a floor rail (6) connectable to a vehicle floor, on which the seat rail (7) is slidably guided along a longitudinal direction (X), wherein the longitudinal adjuster (4) comprises a drive unit (8) for adjusting the seat rail (7) along the longitudinal direction (X) relative to the floor rail (6), wherein the drive unit (8) comprises an electric motor (9), a gear arrangement (10) according to one of the preceding claims and a spindle (11) fixed to the floor rail (6) or to the seat rail (7), wherein the electric motor (9) is operatively connected to the spindle (11) via the gear arrangement (10) in order to convert the movement of the spindle (11) into a longitudinal adjustment of the vehicle seat (1) via a spindle nut (12) attached to the seat rail (7) or to the floor rail (6). [6] Longitudinal adjuster (4) according to claim 5, wherein a pitch of a nut thread of the spindle nut (12) is configured for self-locking between the spindle nut (12) and the spindle (11) for load transfer in the event of a crash. [7] Longitudinal adjuster (4) according to claim 6, wherein the nut thread is designed as a trapezoidal thread. [8] Longitudinal adjuster (4) according to one of claims 5 to 7, wherein the electric motor (9) is positioned in front of the gear arrangement (10). [9] Longitudinal adjuster (4) according to any one of claims 5 to 8, wherein the electric motor (9) is arranged completely within the seat rail (7) or upper rail or partially or completely outside the seat rail (7) or upper rail. [10] Longitudinal adjuster (4) according to one of claims 5 to 9, wherein the electric motor (9) and the gear assembly (10) are arranged at a front end or rear end of the upper rail and / or wherein the electric motor (9) and the gear assembly (10) are arranged at least partially in a cavity (33) formed between the seat rail (7) and the bottom rail (6) through a recess. [11] Vehicle seat (1) comprising at least one longitudinal adjuster (4) according to any one of claims 5 to 10.

Images