Actuator for a seat cushion lift mechanism of a vehicle seat

Abstract

The present invention relates to an actuator (20) for a vehicle seat, comprising: a motor (29); a reduction gear (36) driven by an output shaft of the motor (29), the reduction gear (36) comprising an eccentric cam (44) wheel (43) driving a track gear (47); an output member (33) forming an inner ring (48) receiving the track gear (47), the pinion (27) and the inner ring (48) being aligned along an axis of rotation (A) of the output member (33); a friction member (100; 200; 300) functionally arranged between a cam (44) of the eccentric cam (44) wheel (43) and the output member (33). The friction member (100; 200; 300) is configured to generate a resistive torque on the asymmetric output member (33) depending on a direction of rotation of the output member (33) around the axis of rotation (A).

Description

Technical Field

[0001] This invention relates to an actuator for vehicle seats, particularly motor vehicle seats. More particularly, this invention relates to an actuator for a seat cushion raising mechanism for vehicle seats, especially motor vehicle seats. Background Technology

[0002] In particular, in the automotive field, vehicle seats with a seat cushion frame arranged on a base are known, and the seat cushion is equipped with seat cushion lifting movement.

[0003] In this type of construction, the actuator is provided with an output member that is selectively driven to rotate to raise and / or lower the seat frame. The output member includes teeth that engage with toothed sections facing each other. The toothed sections are kinematically related to raising and lowering the seat. Application FR-A-3 086 597 describes an example of such an actuator.

[0004] The actuator includes a reduction gear with a high reduction ratio to change the rapid rotation of the electric motor to the slow or very slow rotation of the output member. The reduction gear under consideration has the functional clearance required for its operation in all cases. This clearance is particularly present when the electric motor is not controlled and the output pinion should not move.

[0005] In addition, seat cushion lift movements are typically equipped with an upward elastic return system to compensate for all or part of the weight of the occupant sitting in the seat, and secondarily to compensate for a portion of the weight of the seat itself.

[0006] The clearance of the reduction gear can be perceptible, especially when the load polarity changes (e.g., when an occupant sits on the seat or gets off the seat).

[0007] To conceal the backlash of the reduction gear, FR-A-3 135 026 discloses an actuator comprising a friction ring mounted around and rotatably fixed to an output member. The friction ring includes a skirt, and the actuator housing includes an inner bearing for receiving the skirt. The skirt contacts at least the inner bearing to create frictional braking between the output member and the inner bearing.

[0008] Through these arrangements, friction is generated in the contact between the skirt and the inner bearing, and this friction acts as a brake when rotational torque is applied to the output pinion.

[0009] However, when the actuator is motorized, the friction ring tends to reduce actuator efficiency. Summary of the Invention

[0010] This disclosure improves upon this situation.

[0011] To this end, a vehicle seat actuator is proposed, which includes: - A motor, which has an output shaft. - A reduction gear, driven by the output shaft of the motor, the reduction gear including an eccentric cam wheel that drives the track gear. - An output component forming a pinion and an internal gear ring adapted to receive the track gear, the pinion and the internal gear ring being aligned along the rotation axis of the output component. - A friction member, functionally arranged between the cam of the eccentric cam wheel and the output member, the friction member being configured to generate a resistance torque on the asymmetric output member depending on the direction of rotation of the output member about the axis of rotation.

[0012] According to a preferred embodiment, the vehicle seat actuator includes one or more of the following features, either individually or in combination: - The track gear is adapted to move in a circular translation within the internal gear ring of the output member; - The vehicle seat actuator includes a slider for guiding the track gear to make circular translations; - The friction member is slender and extends spirally around the axis of rotation of the output member; - The friction member is attached to the cam of the eccentric cam wheel at the first end, and the friction member contacts the radial inner wall of the output member near the second free end; - The first end of the friction member is clamped and received in a receiving recess formed in the cam of the eccentric cam wheel; -The friction component includes a central gear ring and a plurality of arc arms, which are located between a first end fixed to the central gear ring and a second free end; - The friction member includes a central gear ring and a plurality of arms, each arm extending substantially in a direction inclined relative to the radial direction between a first end fixed to the central gear ring and a second free end bent in an orthogonal radial direction; - The output member includes a receiving recess for receiving the friction member, the receiving recess preferably being axially arranged between the pinion and the internal gear ring of the output member, and the friction member preferably contacting the front surface of the receiving recess perpendicular to the rotation axis of the output member; and - The central gear ring of the friction member contacts the front surface of the cam of the eccentric cam wheel perpendicular to the axis of rotation of the output member, and the second end of each of the arms contacts the radial inner surface of the output member.

[0013] According to another aspect, a vehicle seat is described, which includes actuators as described above in all combinations thereof.

[0014] The vehicle seats may specifically include: -Base; - Seat cushion frame; - At least one hinge mechanism connecting the seat cushion frame to the base, each hinge mechanism including at least one connecting rod, the at least one connecting rod being mounted to rotate freely relative to the seat cushion frame at a first end and freely rotate relative to the base at a second end; - At least one actuator as described above, in any combination thereof, the at least one actuator being used to control the rotation of the at least one connecting rod relative to the base or the seat frame.

[0015] According to another aspect, a vehicle seat is proposed, the vehicle seat comprising: - Seat cushion frame; - A device for raising the front edge of the seat; - At least one connecting rod, which connects the seat cushion frame to the seat front edge lifting device; - At least one actuator as described above, in any combination thereof, the at least one actuator being used to control the rotation of the at least one connecting rod relative to the seat cushion frame or the seat front edge raising device. Attached Figure Description

[0016] Other features, details, and advantages will become apparent upon reading the following detailed description and analysis of the accompanying figures, in which: [ Figure 1 [Illustration of a vehicle seat with adjustable seat height]

[0017] [ Figure 2 ] showed [ Figure 1 Details of the seat cushions in the vehicle.

[0018] [ Figure 3 ] is available in [ Figure 1 The image shows a perspective view of the actuator used in the vehicle seat.

[0019] [ Figure 4 ]yes[ Figure 3 An exploded perspective view of the actuator.

[0020] [ Figure 5 ]yes[ Figure 3 The actuator in the [] Figure 3 The cross-sectional view of section VV in [].

[0021] [ Figure 6 ]yes[ Figure 3 Details of the longitudinal cross-sectional view of the actuator shown.

[0022] [ Figure 7 ] is from along [ Figure 6 ] Observed in the cross section of plane VII-VII Figure 3 The perspective view of the actuator shown.

[0023] [ Figure 8 ] shows that it can be displayed in [ Figure 3 The image shows an example of a friction element used in a variant of the actuator.

[0024] [ Figure 9 ] is used Figure 8 The friction components of ] Figure 3 A perspective view of the longitudinal section detailing the actuator variant.

[0025] [ Figure 10 ] shows the use of [ Figure 8 The friction components of ] Figure 3 The longitudinal section of the actuator variant.

[0026] [ Figure 11 ] shows the use of [ Figure 8 The friction component shown in the figure [ Figure 3 The cross-section of the actuator variant shown is shown.

[0027] [ Figure 12 ] is with [ Figure 11 Similar views.

[0028] [ Figure 13 ] is available in [ Figure 3 A perspective view of another example of a friction element used in a variant of the actuator shown.

[0029] [ Figure 14 ] shows the use of [ Figure 13 The friction component shown in the figure [ Figure 3 The cross-section of the actuator variant shown is shown. Detailed Implementation

[0030] In the various figures, the same reference numerals refer to the same or similar features. For the sake of brevity, only elements useful for understanding the described embodiments are shown in the figures, and they are described in detail below.

[0031] In the following description, when referring to terms that define absolute position (such as the terms "front", "rear", "top", "bottom", "left", "right", etc.) or terms that define relative position (such as the terms "above", "below", "upper", "lower", etc.) or qualifiers that refer to orientation (such as "horizontal", "vertical", etc.), reference is made to the orientation of the accompanying drawings or the orientation of the vehicle seat in its normal use position, unless otherwise stated.

[0032] Specifically, the longitudinal direction X refers to the longitudinal direction of the seat. The longitudinal direction of the seat is considered to be the same as the longitudinal direction of the motor vehicle in which the seat is installed. This longitudinal direction X corresponds to the normal direction of travel of the vehicle. The longitudinal direction X is horizontal. The lateral direction Y of the seat therefore corresponds to the lateral or sideways direction of the motor vehicle. This lateral direction corresponds to the direction perpendicular to the normal direction of travel of the vehicle. The lateral direction Y is horizontal. Finally, the vertical direction Z is the vertical direction of the seat, which is perpendicular to both the longitudinal and lateral directions.

[0033] [ Figure 1 A vehicle seat 10 is schematically shown, comprising a seat cushion 11 with a seat cushion frame 12 and a backrest 13 with a backrest frame 14 mounted on the seat cushion frame 12. The seat cushion frame 12 is mounted on a base 15 via one or more hinge mechanisms. The backrest frame 13 may be secured to a headrest 16, which is connected to the backrest frame 13 via one or more headrest 16 attachment sockets or pins 17. In particular, the hinge mechanism may be a raising mechanism and / or one or two tilting mechanisms, which may be particularly, but not exclusively, obtained via connecting rods 18a, 18b. For example, for each of the connecting rods 18a, 18b, the lower end is connected to the base 15 and the upper end is connected to the seat cushion frame 12 of the vehicle seat 10. More specifically, in the example shown, the first connecting rod 18a connects the front portion 15a of the base 15 (mounted to pivot about a first transverse axis A1) to the front portion 12a of the seat frame 12 (mounted to pivot about a second transverse axis A2), and the second rear connecting rod 18b connects the rear portion 15p of the base 15 (mounted to pivot about a third transverse axis A3) to the rear portion 12p of the seat frame 12 (mounted to pivot about a fourth transverse axis A4). In the example shown, the pivoting mounts of both the first connecting rod 18a and the second connecting rod 18b have axes A1 to A4 parallel to the transverse direction Y.

[0034] The seat cushion frame 12 has a similar architecture on the right and left sides. [In [ Figure 1 The image shows only one side. On the side not shown, the seat 10 has additional connecting rods between the seat cushion frame 12 and the base 15, which are equivalent to or even the same as the connecting rods 18a and 18b shown.

[0035] If desired, the seat cushion 11 of the seat 10 may also be equipped with a front edge that is movable in height and / or longitudinal extension. In the case of tilting movement of the front edge, an auxiliary connecting rod 19 connects the seat cushion frame 12 to the front edge, and the auxiliary connecting rod 19 is movable via an actuator 20 through a toothed section 21. Furthermore, the base 15 is slidably mounted relative to the vehicle floor P via a longitudinal moving member 22, which includes a fixed track 22b attached to the vehicle floor P and a movable track 22a fixed to the aforementioned base 15. As is known in the art, the backrest 13 is pivotable relative to the seat cushion 11, and in particular, the backrest frame 14 is pivotable relative to the seat cushion frame 12. The connecting rods 18a, 18b can be moved independently by corresponding control devices, or simultaneously controlled by a synchronization control device or by mechanical linkages (not shown) that can connect them. When the first connecting rod 18a rotates trigonometrically via the actuator 20, the front portion 11a of the seat cushion, connected to the seat, rises upwards; conversely, when the first connecting rod 20a rotates clockwise, the front portion 11a of the seat cushion 11 lowers towards the floor. Similarly, when the second connecting rod 18b rotates trigonometrically via the other actuator 20, the rear portion 11p of the seat cushion 11 rises upwards; and when the second connecting rod 18b rotates clockwise, the rear portion 11p of the seat cushion 11 lowers towards the floor P. When both connecting rods 18a and 18b are operated simultaneously, the seat cushion 11 moves substantially parallel to the floor P; this movement is referred to as "raising." A tilting movement of the seat cushion 11 is achieved when the first connecting rod 18a is operated while the second connecting rod 18b remains stationary, or vice versa. [According to...] Figure 1 The arrangement schematically shown in the diagram includes a front hinge mechanism for connecting rod 18a, which may be equipped with a return member 23. This return member tends to pivot connecting rod 18a in a triangular direction and apply an upward torque to the front portion 11a of seat cushion 11, such that the effects of gravity generated by the weight of seat 10 and / or the occupant mounted on seat 10 can be at least partially compensated by the action of the return member 23. A similar return member may be provided on the second connecting rod 18b. This return member may take any other form, such as a torsion bar, which may advantageously be one of the crossbars mounted on axes A1 to A4.

[0036] like[ Figure 2As shown, the front connecting rod 18a (and correspondingly the rear connecting rod 18b) is securely connected to a crossbar that extends along the transverse axis Y and connects the shown connecting rods 18a and 18b to an equivalent connecting rod arranged on the other side (not shown) of the seat cushion 11. Furthermore, the connecting rod 18a is securely connected to a control flange 25, which is in the form of a metal plate extending along planes X and Z. The control flange 25 is directly connected to the crossbar 24 and / or the connecting rod 18a and has a toothed section 26 at one end, which is substantially circular, designed to engage with an actuator 20, which includes an output pinion 27 that directly engages with the toothed section 26. Preferably, such an actuator 20 is arranged on only one side of the seat cushion frame 12 of the seat 10. The other side may not have an actuator 20. The output pinion 27 is arranged to rotate about an axis A that is substantially parallel to the transverse axis Y. A second actuator similar to the first actuator 20 may be provided to drive the rear connecting rod 18b in a similar manner.

[0037] In the following text, according to [ Figure 3 ]to[ Figure 7 The first example actuator 20 will be described in more detail below.

[0038] like[ Figure 3 As shown, actuator 20 includes a motor 29, a housing 30 (with a housing 31 and a flange or cover 32) forming a fixed support relative to the seat cushion 11 of vehicle seat 10, and an output member 33 forming an output pinion 27. The housing 31 and cover 32 are attached together, for example, by a threaded member 34. A reinforcing element 35 may also be disposed between the housing 31 and the cover 32. Actuator 20 also includes a reduction gear 36 (in […] Figure 3 (Not visible in []), will be specifically relative to [ below] Figure 4 ]and[ Figure 5 To describe it.

[0039] The housing 31 is formed in a bell or bowl shape. In the example shown, the housing 31 is formed of a plastic material. Such a plastic material can be ABS, polypropylene, polyethylene, polyamide, etc. However, the housing 31 can also be formed of aluminum alloy, magnesium alloy, or any lightweight metal alloy.

[0040] Motor 29 extends along an axis perpendicular to the rotation axis A of output member 33 and includes a rotor at its end carrying a helical gear thread 38 centered on the axis of motor 29. The helical gear thread 38 extends inside housing 31. The helical gear thread 38 engages with the first external gear ring 39 of input member 40 of reduction gear 36. Input member 40 is rotatable about axis A via a shaft 41 attached to housing 31, preferably rotatable about the rotation axis A. Shaft 41 may be integral with output member 33, or output member 33 may be attached to shaft 41.

[0041] The input component 40 includes a second internal gear ring 42 adapted to drive an eccentric cam wheel 43 to rotate about a rotation axis A. This eccentric cam wheel features a cam 44 that is eccentric relative to the rotation axis A. The cam 44 is generally cylindrical, with its axis parallel to the rotation axis A. Therefore, the cam 44 takes the form of a substantially cylindrical pin, its axis parallel to and offset relative to the rotation axis A of the eccentric cam wheel 43.

[0042] Cam 44 extends through a first opening 45 of slider 46, which guides a track gear 47 driven by cam 44 of eccentric cam wheel 43. Gear 47 is received in internal gear ring 48 of output member 33. Track gear 47 has a smaller diameter and number of teeth than internal gear ring 48 of output member 33 in order to engage with the latter and produce a reduction ratio in the manner described below.

[0043] The track gear 47 is locked so that it cannot rotate by itself around an axis parallel to the axis of rotation A of the output member 33 via the slider 46.

[0044] Therefore, such as [ Figure 5 As shown, the slider 46 includes at least one first longitudinal guide element 50 and at least one second longitudinal guide element 51 in two vertical longitudinal directions in a plane perpendicular to the rotation axis A of the output member 33.

[0045] The first longitudinal guide element 50 is adapted to mate with the first mating element 52 of the housing 31 of the housing 30. The first longitudinal guide element 50 has a first guide surface 53, which is adapted to slide in or against the first mating element 52.

[0046] The first guide surface 53 is adapted to guide the slider 46 so that it can only move along a line relative to the housing 31 of the outer casing 30.

[0047] For example, the first guide surface 53 can lock the slider 46 so that it cannot translate relative to the housing 30 in the vertical direction Z, which is perpendicular to the longitudinal X direction and the transverse Y direction.

[0048] The slider 46 can also be locked to prevent rotation about the axis of rotation A relative to the housing 30. Conversely, the slider 46 can slide freely relative to the housing 31 in the longitudinal direction X.

[0049] Therefore, the cooperation of the first longitudinal guide element 50 and the first mating element 52 locks the slider 46 so that it cannot translate in the vertical direction Z relative to the housing 31 or rotate about the rotation axis A, while allowing it to slide freely in the longitudinal direction X.

[0050] The second longitudinal guide element 51 is adapted to engage with the second mating element 54 of the gear 47. For this purpose, the second longitudinal guide element 51 has a second guide surface 55 adapted to slide against the second mating element 54. Thus, the track gear 47 can only move along a line relative to the slider 46.

[0051] The second guide surface 55 can, for example, lock the gear 47 so that it cannot translate relative to the slider 46 in the longitudinal direction X. The track gear 47 can also be locked to prevent rotation about the axis of rotation A relative to the slider 46 in the vertical direction Z.

[0052] The engagement of the second longitudinal guide element 51 with the second mating element 54 thus locks the track gear 47 so that it cannot translate relative to the slider 46 in the longitudinal direction X and rotate about the axis of rotation A, while allowing it to slide freely in the vertical direction Z.

[0053] Thus, gear 47 can only move in a circular translation relative to housing 30 in a plane perpendicular to the axis of rotation A, and is specifically locked to prevent rotation about the axis of rotation relative to housing 30, due to the engagement of the first longitudinal guide element 50 and the second longitudinal guide element 51 of slider 46 with the first mating element 52 and the second mating element 54 of housing 31 of housing 30 and the track gear 47.

[0054] The complete circle of the track gear 47 within the internal gear ring 48 of the output member 33 causes the output member 33 to be displaced relative to the housing 31 at an angle by the difference in the number of teeth between the track gear 47 and the internal gear ring 48, thereby generating the reduction ratio of the reduction gearbox 36.

[0055] In one embodiment, the first longitudinal guide element 50 may be formed by a plurality of extensions (e.g., two or four extensions) of a rectangular cross-section protruding from the body of the slider 46 in the longitudinal direction X. The extensions may extend in pairs on either side of the body of the slider 46. Thus, the extensions may form a “U” shape with the body on either side. The two extensions may be symmetrical with respect to the longitudinal midplane. The side wings of the extensions may then form a first guide surface 53. The first mating element 52 may then include a longitudinal groove in the housing 30 (e.g., in the housing 31) to receive the extensions. The second longitudinal guide element 51 may be formed by a straight opening in the slider 46, the side wings of which form a second guide surface 55. The second mating element 54 may then include an axially projecting square-section finger of the track gear 47 adapted to fit into the straight opening. Alternatively, other shapes for the first longitudinal guide element 50 and the second longitudinal guide element 51, as well as the first mating element 52 and the second mating element 54, are contemplated.

[0056] like[ Figure 4 As shown, bearing 56 can be arranged between output member 33 and cover 32 to guide the rotation of output member 33.

[0057] Additionally, according to the first example, the actuator 20 here includes a friction member 100, which is functionally arranged between the cam 44 of the eccentric cam wheel 43 and the output member 33.

[0058] In particular, such as [ Figure 4 As can be seen in the image, the friction member 100 is in the form of cylindrical strands, extending by winding around the axis of rotation A of the output member 33. Therefore, the friction member 100 extends in a helical shape. The friction member 100 is, for example, polygonal in cross-section, particularly rectangular or square, circular or elliptical.

[0059] like[ Figure 7 As can be seen in the image, the first end 102 of the friction member 100 is attached to the cam 44 of the eccentric cam wheel 43. Here, for this purpose, the first end 102 is clampedly received in a receiving recess 104 formed on the cam 44, which opens on the side surface of the cam 44.

[0060] The first friction member 100 scrapes against the radially inner surface 108 of the receiving recess 110 formed in the output member 33 near its second end 106 opposite to the first end 102. The receiving recess 110 accommodating the friction member 100 is axially arranged between the radially inner gear ring 48 and the pinion 27 of the output member 33.

[0061] The friction member 100 is shaped such that when the actuator 20 drives the reduction gear 36 (and thus the output member 33) in a first direction, particularly in a direction that tends to resist the force generated by the weight of the seat occupant, the friction member 100 on the radially inner surface 108 of the output member 33 is reduced. In this case, the friction member 100 tends to curl around itself to reduce its outer diameter. In this way, the efficiency of the actuator 20 remains at a high level.

[0062] Conversely, if the reduction gear 36 is driven in a second direction opposite to the first direction, and the output member 33 is also driven, the friction of the friction member 100 on the radially inner surface 108 of the output member 33 increases significantly. Here, in this rotational direction of the reduction gear 36, the friction of the friction member 100 on the radially inner surface 108 of the output member 33 tends to increase the diameter of the friction member 100, and similarly, the friction of the output member 33 on its radially inner surface 108 tends to increase. This reduces the risk of desynchronization in the actuator 20 by braking the gear set 36 as it is driven from the output member 33 to the motor 29. It also reduces the risk of popping noise in the gear set as it moves from motion driven by the motor 29 to motion driven by the output member 33.

[0063] [ Figure 8 A second example of the friction member 200 is shown. As shown, the friction member 200 first includes a central gear ring 202 that defines a central opening 204 adapted to receive a rotating shaft 41. The friction member 200 also includes a plurality of arms 206, in this case three arms 206. In the example shown, the arms 206 are identical. Here, each arm 206 extends substantially orthogonally radially relative to the axis of rotation A of the output member 33 between a first end 208 fixed to the central gear ring 204 and a free second end 210. Preferably, a gap 212 is provided between the arms 206, i.e., between the second end 210 of the first arm 206 and the first end 208 of the adjacent second arm 206. Here, each arm 206 has a reduced cross-section in the intermediate portion 214 connecting the first end 208 and the second end 210. In contrast, the first end 208 and the second end 210 have larger cross-sections. Therefore, only the first end 208 and the second end 210 of the arms 210 may contact the radially inner wall 108 of the output member 33. Additionally, here, an axial bead 216 is formed on the radially outer surface of the first end 208 of each arm 206 for contacting the radially inner surface 108 of the output member 33.

[0064] Furthermore, the central gear ring 202 has a pin 218 adapted to be received in a complementary receiving recess 220 in the front surface 222 of the cam 44 to help hold the friction member 200 in place relative to the cam 44. The front surface 222 extends in a plane perpendicular to the axis of rotation A of the output member 33.

[0065] like[ Figure 10 As shown, the second friction member 200 (here, the central gear ring 202 of the second friction member 200) contacts the cam 44 (here, the front surface 222 of the cam 44 perpendicular to the axis of rotation A of the output member 33). The second friction member 200 contacts the radial surface 108 of the output member 33. On the one hand, through the axial crimp 216 contact, the axial crimp ensures substantially constant friction regardless of the relative rotation direction of the friction members 200; and - On the other hand, through the contact of the end 210 of the arm 206, the frictional force of this end on the output member 33 can depend on the rotational directions R1 and R2 of the output member 33, such as [ Figure 11 ]and[ Figure 12 The arrows F1 and F2 are shown in the diagram.

[0066] Alternatively, the second friction member 200 may also contact the front surface 224 of the receiving recess 110, which is perpendicular to the axis of rotation A of the output member 33, via the first end 208 and / or the second end 210 of the arm 206. This contact may also be substantially constant regardless of the direction of rotation of the output member 33.

[0067] [ Figure 13 ]and[ Figure 14 A third example of a friction member 300 that can be implemented in the drive device 20 as described above is shown.

[0068] As shown, the friction member 300 according to this third example first includes a central gear ring 302 that defines a central opening 304 adapted to receive a rotating shaft 41. The friction member 300 also includes a plurality of arms 306, in this case fourteen arms 306. In the example shown, the arms 306 are identical. Here, each arm 306 extends substantially radially from the axis of rotation A of the output member 33 between its first ends fixed to the central ring 304. The opposite free ends 310 of each arm 306 are bent in an orthogonal radial direction. As shown, a gap is preferably provided between the arms 306. Here, the gaps between all the arms 306 are substantially equal, except for a pair of arms separated by a pin 312 on the central gear ring 302, which may be adapted to be received in a receiving recess complementary to the front surface of the cam 44 to help hold the friction member 300 in place relative to the cam 44.

[0069] Here, the cross-section of each arm 306 is essentially constant.

[0070] In this example, the third friction member 300 contacts the eccentric cam wheel 43 via the front surface of the cam 44 on one hand, and on the other hand, contacts the radial inner surface of the output member 33.

[0071] Due to the shape of the friction member 300, especially the shape of the arm 306, the friction applied by the friction member to the output member 33 depends on the rotation direction of the output member 33.

[0072] This invention is not limited to the examples described above by way of non-limiting description. Rather, those skilled in the art will readily apply various modifications of this invention.

Claims

1. An actuator (20) for a motor vehicle seat, said actuator comprising: - Motor (29), the motor having an output shaft - Reduction gear (36), which is driven by the output shaft of the motor (29), the reduction gear (36) includes an eccentric cam (44) wheel (43) that drives the track gear (47). - Output member (33), the output member (33) forming a pinion (27) and an internal gear ring (48) adapted to receive the track gear (47), the pinion (27) and the internal gear ring (48) being aligned along the rotation axis (A) of the output member (33), - Friction member (100; 200; 300), which is functionally arranged between the cam (44) of the eccentric cam (44) wheel (43) and the output member (33), the friction member (100; 200; 300) being configured to generate a resistance torque on the asymmetric output member (33) depending on the rotation direction of the output member (33) about the rotation axis (A).

2. The actuator for a vehicle seat according to claim 1, wherein the track gear (47) is adapted to move in a circular translation within the internal gear ring (48) of the output member (33).

3. The actuator for a vehicle seat according to claim 1, wherein the friction member (100) is elongated and extends helically about the axis of rotation (A) of the output member (33).

4. The actuator for a vehicle seat according to claim 3, wherein the friction member (100) is attached at a first end (102) to the cam (44) of the eccentric cam (44) wheel (43), and the friction member (100) contacts the radial inner wall (108) of the output member (33) near the second free end (106).

5. The actuator for a vehicle seat according to claim 4, wherein the first end (102) of the friction member (100) is clampedly received in a receiving recess (104) formed in the cam (44) of the eccentric cam (44) wheel (43).

6. The actuator for a vehicle seat according to claim 1, wherein the friction member (200) comprises a central gear ring (202) and a plurality of arcuate arms (206) between a first end (208) fixed to the central gear ring (202) and a second free end (210).

7. The actuator for a vehicle seat according to claim 1, wherein the friction member (300) comprises a central gear ring (302) and a plurality of arms (306), each arm (306) extending substantially in a direction inclined relative to the radial direction between a first end fixed to the central gear ring (302) and a second free end (310) bent in an orthogonal radial direction.

8. The actuator for a vehicle seat according to claim 6, wherein the output member (33) includes a receiving recess for receiving the friction member (110).

9. The actuator for a vehicle seat according to claim 8, wherein the receiving recess (110) is axially arranged between the pinion (27) and the internal gear ring (48) of the output member (33).

10. The actuator for a vehicle seat according to claim 9, wherein the friction member (200) contacts the front surface (224) of the receiving recess (110) perpendicular to the axis of rotation (A) of the output member (33).

11. The actuator for a motor vehicle according to claim 6, wherein the central gear ring (202; 302) of the friction member (200; 300) contacts the front surface (222) of the cam (44) of the eccentric cam (44) wheel (43) perpendicular to the axis of rotation (A) of the output member (33), and wherein the second end of each of the arms contacts the radial inner surface (108) of the output member (33).

12. A vehicle seat (10) comprising an actuator (20) according to any of the preceding claims.

Images