Seat depth-adjustable vehicle seat with a first seat section and a second seat section

Abstract

Seat depth-adjustable vehicle seat comprising a first seat section (33), a second seat section (34), and a longitudinal adjustment device (44) arranged between the first seat section (33) and the second seat section (34), enabling a sliding movement in a first seating direction (54) of the first seat section (33) relative to the second seat section (34), characterized in that a rack (52) extending substantially in the first seating direction (54) is connected to the second seat section (34), that a primary gear (56) is provided which engages with this rack (52), that a secondary gear (60) is provided which is rotatably connected to the primary gear (56), that a toothed strip (62) extending substantially in the first seating direction (54) and engaging with the secondary gear (60), and that a third seat section (64) is provided.which is arranged to be slidable in the first seating direction (54) and which is connected to the toothed strip (62).

Description

[0001] The invention relates to a motor vehicle seat with adjustable seat depth according to the preamble of patent claim 1. Such a motor vehicle seat is known from DE 196 28 381 A1. Furthermore, DE 698 27 303 T2 discloses a vehicle seat with adjustable seat depth, in which a second seat part, which is a front seat part, can be adjusted relative to a first, rear seat part by means of an electric motor. In the vehicle seat previously known from DE 199 13 503 A1, objects can be positioned at different distances from one another by means of an adjustment device. DE 199 55 296 C1 also shows a similar vehicle seat. Further vehicle seats and adjustment devices are disclosed in the documents DE 199 25 306 A1, JP S59-117 539 U, DE 10 2008 030 608 A1, DE 10 2008 006 547 A1, JP 2010 - 172 430 A, KR 10 2009 0 070 297 A and DE 197 38 199 A1.

[0002] One problem with seat depth adjustment devices in the seating area is that, on the one hand, the upholstery body needs to be adjusted or compensated for in some way, meaning it has to accommodate changes in length. On the other hand, the upholstery cover must also be designed accordingly. The upholstery should be of the same quality throughout, regardless of the seat depth adjustment. Furthermore, it is desirable that the cover have as few wrinkles and gaps as possible, whether covered or uncovered.

[0003] Starting from the vehicle seat of the type mentioned at the outset, the object of the invention is to further develop the previously known vehicle seat in such a way that the seat area can be adjusted in such a direction that the upholstery can be designed more advantageously than before, but in particular also the cover can be designed more advantageously.

[0004] This object is achieved on the basis of the seat depth-adjustable motor vehicle seat of the type mentioned at the outset in that a toothed rack is connected to the second seat part, which extends substantially in the first seat direction, that a primary gear is provided which engages with this toothed rack, that a secondary gear is provided which is rotationally connected to the primary gear, that a toothed strip is provided which extends substantially in the first seat direction and which engages with the secondary gear, and that a third seat part is provided which is arranged to be displaceable in the first seat direction and which is connected to the toothed strip.

[0005] In this motor vehicle seat, the motor drive, which is responsible for and intended for the longitudinal adjustment between the first seat section and the second seat section, is also indirectly used for the drive between the second seat section and a third seat section. This is achieved by providing a primary gear and a cooperating rack, which are moved against each other by the longitudinal adjustment. The linear movement is thus converted back into a rotary movement. This rotary movement is then advantageously transmitted to the secondary gear, which engages the rack assigned to the third seat section and moves with the third seat section, or directly drives the third seat section.

[0006] This allows all seat sections to be driven synchronously. Two seat sections are moved with just one motorized drive for the longitudinal adjustment. The first seat section moves relative to the second seat section, and the third seat section also moves relative to the first or second seat section. Overall, the seating area is divided into three or possibly more seat sections. This makes it easier to bridge gaps and adjust the upholstery fabric, for example, to allow it to sag.

[0007] Preferably, the third seat part forms a seat front edge. In another preferred embodiment, the axis of the primary gear is connected to the second seat part and thus moves with it. In an alternative, the primary gear is enclosed on both sides between a rack and pinion and is engaged. In this case, the gear follows half of the movement of the second seat part relative to the first. This movement can be used to directly drive the third seat part or, in turn, to provide a secondary gear that has a desired tooth ratio to the primary gear and is engaged with the rack. In the latter case, greater travel of the third seat part can be achieved than in the first case.

[0008] Further advantages and features of the invention will become apparent from the remaining claims and the following description of three non-limiting embodiments of the invention. The drawings show: Fig. 1: A perspective view, partly as an assembly image, for a first embodiment; Fig. 2: A side view of a second embodiment, which is constructed similarly to the first embodiment according to Fig. 1, shows a seating area at its greatest seat depth; Fig. 3: A representation like Fig. 2, but now in the position of lowest seat depth, and Fig. 4: A perspective view similar to Fig. 1 but now for a third embodiment.

[0009] In the following, the first and second embodiments are described according to the Fig. 1 to Fig. 3, these two embodiments are closely related. The further implementation will then be discussed, particularly insofar as it differs from the previously discussed ones.

[0010] The adjustable vehicle seat has a base frame 20 in a conventional manner. It has a longitudinal adjustment mechanism 22 with two pairs of rails, which are designed according to the prior art and support front rockers 24 and rear rockers 26. A seat support is held on these rockers 24, 26, which here is essentially formed by a left side part 30 and a right side part 32, each of which is pivotally connected to the rockers 24, 26. These two side parts 30, 32 form a first seat part 33.

[0011] A cushion shell 34 is also provided. It occupies approximately 40 to 70% of the seat depth and forms the side bolsters. The cushion shell 34 forms the second seat part. The second seat part has elongated holes 36 in its rear area, through which, when assembled, holders 38, which are provided on the side parts 30, 32, pass. This creates an articulated longitudinal guide.

[0012] The two side parts 30, 32 are connected to each other by a front cross member 40. A front end of a longitudinal adjustment device 44 is held on this in a housing 42. As can be seen from the Fig. 2 and Fig. 3, this is designed as a spindle drive; reference is made to the applications WO 2003 / 068 551 A1, DE 103 53 245 A1, DE 17 55 740 A, US 6 260 922 B1, DE 10 2005 028 620 A1 and DE 198 15 283 C2. The longitudinal adjustment device 44 has a drive housing 46, which is held in a holder 48, which in turn is connected to the first seat part 33. In the drive housing, a spindle nut is rotatably mounted in a manner known per se but not shown here, which engages around a spindle 50. The axial position of this spindle 50 can be adjusted relative to the drive housing 46, as can be seen from the comparison of the Fig. 2 and Fig. 3 shows the two end positions.

[0013] A rack 52 is connected to the second seat part 34 and extends in a first seat direction 54 (see arrow). This lies in the same xz-plane as a second seat direction, which is defined by the longitudinal axis of the spindle 50, but differs slightly, for example, by 5 to 10 degrees. The angle to the x-axis is greater in the first seat direction 54 than in the second seat direction.

[0014] A primary gear 56 meshes with the rack 52. This primary gear 56 is rotatable about an axis 58. This axis runs in the xz plane and is perpendicular to the first seating direction 54.

[0015] A secondary gear 60 is drivingly connected to the primary gear 56; in the illustrated embodiment, these two gears 56, 60 are formed as a single piece. The secondary gear 60 has a significantly larger diameter than the primary gear 56, resulting in a gear ratio of at least 1 to 1.5, preferably at least 1 to 2, between the two. A toothed rack 62, which is parallel to the rack 52, engages the secondary gear 60. Both the toothed rack 62 and the rack 52 can move relative to each other in the first seating direction 54.

[0016] When the longitudinal adjustment device 44 is driven from the Fig. In the position shown in Figure 3, the rack 52 is pushed forward and thereby moved relative to the primary gear 56. If the first seat part 33 is considered stationary, the axle 58 also remains stationary, thus the primary gear 56 also remains stationary. Due to the movement of the second seat part 34, it is rotated. This also rotates the secondary gear 60, which pushes the rack 62 forward until the Fig. 2 is reached. Due to the gear ratio between the primary gear 56 and the secondary gear 60, the toothed rack 62 moves a significantly greater distance in the first seat direction 54 during the adjustment movement of the longitudinal adjustment device 44, approximately twice the distance in the second embodiment. A third seat part 64 is connected to the toothed rack 62. This third seat part 64 forms a seat front edge 66.

[0017] The third embodiment according to Fig. 4 differs from the first embodiment according to Fig. 1 in that the primary gear 56 is now not rotatable about an axis connected to the first seat part. Rather, a rack 68 is connected to the first seat part, which runs parallel to the rack 52. The primary gear 56 is located between the rack 68 and the rack 52. In the embodiment discussed, as in the first embodiment, an elongated hole is provided, which is formed in the second seat part 34. A pin engages in this elongated hole, which is connected at the bottom to the first seat part 33 and at the top to the rack 68. In Fig. 1, the axis 58 is provided instead of this pin.

[0018] When the longitudinal adjustment device 44 is actuated, the rack 68 and the rack 52 are moved relative to each other in the first seat direction 54. This causes the primary gear 56 to rotate. The secondary gear 60, which engages the rack 62 associated with the third seat part 64, also rotates at the same angular velocity.

[0019] The unit comprising primary gear 56 and secondary gear 60 moves relative to both the rack 68 and the rack 52. A suitable guide member is provided, for example, a carriage, which is longitudinally guided at least on one of the rack 52 or the rack 68 or at another location in the first seating direction 54 and has an axis for the gear combination 56, 60.

[0020] By appropriately selecting the ratio of the diameters of the primary gear 56 and the secondary gear 60, the desired increase or decrease ratio can be achieved; it is also possible to equip both gears with the same diameter.

[0021] Between the individual seat parts 33 and 34, as well as 34 and 64, suitable guides known from the prior art are provided, which determine the displacement movements. These include the aforementioned elongated holes 36 and the associated holders 38, as well as the aforementioned elongated hole in the second seat part 34, through which the axis 58 or a pin passes. This also includes an elongated hole 70 in the third seat part 64, which runs in the first seat direction 54 and is passed through by the axis 58, see Fig. 1.

[0022] A seat suspension (not shown) known per se can be arranged between the first seat part 33 and the second seat part 34, which extends or shortens during the adjustment movement between these two seat parts 33, 34.

[0023] Preferably, the rack 52 is at least 30% shorter than the rack 62. The rack 52 and the rack 68 are preferably of identical construction. The parts 52, 62, 68, 56, and 60 are preferably injection-molded parts, in particular made of plastic. In a preferred embodiment, the second seat part 34 is moved approximately 32.5 mm forward relative to the first seat part 33, and the third seat part is also moved approximately 32.5 mm forward relative to the second seat part 34 via the arrangement of the rack 52, gears 56 and 60, and rack 62. The cushion extension is approximately half from the rear and the other half from the front. The longitudinal direction of the longitudinal adjustment device, in particular of the spindle 50, can deviate from the actual direction of the displacement movement between the first seat part 33 and the second seat part 34, for example, by approximately 10 degrees or even 20 degrees. These directions lie in the xz plane.

[0024] This application is a further development of the German patent application 10 2007 037 713 “Seat depth adjustable motor vehicle seat” of 9 August 2007. List of reference symbols 20 base frame 22 Longitudinal adjustment 24 front swing arm 26 rear swing arm 28 seat supports 30 left side panel 32 right side panel 33 first seat part 34 second seat part or cushion shell 36 slot 38 holders 40 front cross member 42 housings 44 Longitudinal adjustment device 46 drive housing 48 bracket 50 spindle 52 rack 54 first seating device 56 primary gear 58 Axis 60 secondary gear 62 toothed strip 64 third seat part 66 front edge of seat 68 rack 70 slot

Claims

[1] Seat depth adjustable vehicle seat with a first seat part (33), with a second seat part (34) and with a longitudinal adjustment device (44) which is arranged between the first seat part (33) and the second seat part (34) and enables a sliding movement in a first seat direction (54) of the first seat part (33) relative to the second seat part (34), characterized bythat a toothed rack (52) is connected to the second seat part (34), which extends substantially in the first seat direction (54), that a primary gear (56) is provided which engages with this toothed rack (52), that a secondary gear (60) is provided which is rotationally connected to the primary gear (56), that a toothed rack (62) is provided which extends substantially in the first seat direction (54) and which engages with the secondary gear (60), and that a third seat part (64) is provided which is arranged to be displaceable in the first seat direction (54) and which is connected to the toothed rack (62). [2] Seat depth adjustable vehicle seat according to claim 1, characterized bythat an axle (58) is connected to the second seat part (34) and has an axis line which runs in the xz plane and transverse to the teeth of the rack (52), and that the primary gear (56) is arranged to be rotatable about the axis line of this axle (58). [3] Seat depth adjustable vehicle seat according to claim 1, characterized by that a rack (68) is provided which is parallel to the first rack (52) and engages with the primary gear (56). [4] Seat depth adjustable vehicle seat according to one of the preceding claims, characterized by that the primary gear (56) has a diameter that is at least 10% smaller than the secondary gear (60), in particular has a diameter that is at least 30% smaller than the secondary gear (60). [5] Seat depth adjustable vehicle seat according to one of the preceding claims, characterized bythat the primary gear (56) and the secondary gear (60) are rigidly connected to one another, in particular are designed as one piece. [6] Seat depth adjustable vehicle seat according to one of the preceding claims, characterized by that the first seating direction (54) is substantially parallel to a second seating direction, that the first seating direction (54) and the second seating direction extend in the xz plane, and that in particular the first seating direction (54) encloses an angle with the x-axis which is at least 5 degrees greater than the angle between the x-axis and that of the second seating direction. [7] Seat depth adjustable vehicle seat according to one of the preceding claims, characterized by that the longitudinal adjustment device (44) has a spindle drive with a spindle (50) and a drive housing (46).

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