JP2020104716A - Vehicular seat - Google Patents

Abstract

To provide a vehicular seat capable of effectively supporting lumbar vertebra of a seating person.SOLUTION: A vehicular seat includes a lumber support plate 12, a pair of links 20A, 20B which connect the lumber support plate 12 to a seat back frame and a driving part 30 which drives the pair of links 20A, 20B. Therein, the pair of links 20A, 20B are arranged to cross to each other and respectively have first rod 21 and second rod 22 rotatably connected on a crossing portion 23, a first end part of the first rod 21 is rotatably fixed to a bracket 24, a second end part is movably engaged with a lumber support plate 12, a first end part of a second rod 22 is movably engaged with a bracket 24 along a guide slit 25, the second end part of the second rod 22 is rotatably fixed to the lumber support plate 12 and the guide slit 25 which guides the first end part of the second rod 22 has a straight line portion and a curved line extended from an end part of the straight line portion.SELECTED DRAWING: Figure 2

Description

The present invention relates to a vehicle seat.

The seatback device described in Patent Document 1 is a seatback device for a seat installed in a vehicle such as an automobile, and includes a lumbar support plate that supports a lumbar vertebra of a seated person. The lumbar support plate is connected to the frame of the seat back via a pair of links, and each link is formed by a first arm and a second arm that intersect in an X shape and are rotatably coupled at the intersecting portion. It is configured.

The frame side end of the first arm is rotatably fixed to the frame, and the frame side end of the second arm is supported by a nut screwed with a screw extending in the seat vertical direction. When the screw is rotated, the nut moves in the seat vertical direction along the screw, and the frame side end of the second arm supported by the nut also moves in the seat vertical direction. Then, the lumbar support plate moves in the seat front-rear direction according to the movement of the end portion of the second arm on the frame side, and the pressing force on the seated person is adjusted.

Japanese Patent Laid-Open No. 5-207920

In the seat back device described in Patent Document 1, the movement of the lumbar support plate is interlocked with the movement of the frame side end of the second arm. However, the movement of the frame side end of the second arm is limited in the vertical direction in which the screw extends, and the movement of the lumbar support plate becomes monotonous. Therefore, the change in the pressing force becomes monotonous, and the change may not be perceived easily. Further, since a screw is provided for each second arm of each link, there is a concern that the cost and weight of the seat will increase.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle seat capable of effectively supporting the lumbar vertebra of a seated person by emphasizing a change in pressing force applied to the seated person.

A vehicle seat according to one aspect of the present invention is provided symmetrically with a lumbar support plate arranged along a backrest surface of a seat back, with a space in the seat width direction, and the lumbar support plate is provided in the seat back frame. A pair of links that are connected to each other and a drive unit that drives the pair of links, wherein the pair of links includes a first rod and a first bridge that are bridged between the lumbar support plate and the seatback frame. Two rods are respectively provided, the first rod and the second rod are arranged so as to intersect with each other and are rotatably coupled at the intersecting portion, and the seatback frame among the both ends of the first rod. The first end located on the side is rotatably fixed to the seat back frame or a bracket attached to the seat back frame, and the second end of the first rod extends along the lumbar support plate. Of the second rod, the first end located on the side of the seat back frame is engaged with the lumbar support plate so that the guide is provided on the seat back frame or the bracket. The seat back frame or the bracket is movably engaged with the slit, the second end of the second rod is rotatably fixed to the lumbar support plate, and the pair of links are By being driven by the drive unit, the first end of the second rod moves along the guide slit, and the guide slit has at least one of a linear portion and both end portions of the linear portion. A curved portion extending from the end.

According to the present invention, it is possible to provide a vehicle seat that can effectively support the lumbar vertebra of a seated person by emphasizing a change in pressing force applied to the seated person.

It is a perspective view of an example of a sheet for explaining the embodiment of the present invention. It is a perspective view of the internal mechanism of the seat back of FIG. It is a side view of the internal mechanism of FIG. It is a schematic diagram which shows operation|movement of the internal mechanism of FIG. FIG. 3 is a schematic diagram showing an operation of a preferable configuration example of the internal mechanism of FIG. 2. FIG. 4 is a schematic diagram showing an operation of a more preferable configuration example of the internal mechanism of FIG. 2. FIG. 9 is a schematic diagram showing an operation of a modified example of the internal mechanism of FIG. 2. It is a schematic diagram of an example of a curved portion of the guide slit of FIG. It is a schematic diagram of the other example of the curved part of the guide slit of FIG. It is a perspective view of other examples of an internal mechanism of a seat back for explaining an embodiment of the present invention. It is a schematic diagram which shows operation|movement of the internal mechanism of FIG.

FIG. 1 shows an example of a vehicle seat for explaining an embodiment of the present invention.

A vehicle seat 1 shown in FIG. 1 is a seat installed in a vehicle such as an automobile, and includes a seat cushion 2 for supporting the buttocks and thighs of an occupant seated on the seat 1 (hereinafter referred to as a seated person), and a seated seat. A seat back 3 that supports the waist and back of the person.

The seat back 3 has a seat back frame 10. The seat back frame 10 includes a pair of back side frames 11 arranged at intervals in the seat width direction and extending in the seat up-down direction, and is formed in a substantially rectangular frame shape. A pad made of a foam material such as urethane foam is covered on the seat back frame 10, and the pad and the seat back frame 10 are covered with a trim cover made of a skin material such as leather, woven fabric, and knitted fabric. The seat cushion 2 also has a frame, a pad, and a trim cover, and is configured similarly to the seat back 3.

Inside the seat back 3, a lumbar support plate 12 that supports the lumbar vertebra of a seated person, a link that connects the lumbar support plate 12 to the seat back frame 10, and a drive unit that drives the link are provided. The lumbar support plate 12 is arranged along the backrest surface of the seat back 3, and is covered by the pad and the trim cover of the seat back 3.

2 and 3 show the internal mechanism of the seat back 3.

The lumbar support plate 12 is connected to the seat back frame 10 via a pair of links 20A and 20B, and the pair of links 20A and 20B are symmetrically provided at intervals in the seat width direction. Hereinafter, the link 20A will be described, and the link 20B will be simplified or omitted by appropriately referring to the symmetrical configuration of the link 20A.

The link 20A includes a first rod 21 and a second rod 22 that are bridged between the lumbar support plate 12 and one backside frame 11 (see FIG. 1) of the seatback frame 10. The first rod 21 and the second rod 22 are arranged so as to intersect each other in an X shape between the lumbar support plate 12 and the backside frame 11, and are rotatably coupled at an intersecting portion 23.

Of both ends of the first rod 21, the first end 21a located on the backside frame 11 side is fixed to the bracket 24 so as to be rotatable around an axis extending in the seat width direction through the first end 21a. The bracket 24 is attached to the backside frame 11. The first end 21 a of the first rod 21 may be fixed to the backside frame 11 without the bracket 24.

The second end 21 b of the first rod 21 is movably engaged with the lower portion of the lumbar support plate 12 along the lumbar support plate 12. For example, a guide having an elongated hole extending along the lumbar support plate 12 is provided in the lumbar support plate 12, and a shaft that is inserted into the elongated hole is provided in the second end portion 21b, and the second end portion is provided via this shaft. 21b and the lumbar support plate 12 may be joined, but in the present example, the second end 21b is not joined to the lumbar support plate 12 and contacts the back surface of the lumbar support plate 12 and slides on the back surface. Move. Due to the load applied to the lumbar support plate 12 when the seated person leans against the seat back 3, the contact between the lumbar support plate 12 and the second end portion 21b is maintained.

The bracket 24 has a guide slit 25. The guide slit 25 is provided below the first end 21 a of the first rod 21 fixed to the bracket 24. Then, the first end 22a of the both ends of the second rod 22 located on the backside frame 11 side is coupled to the bracket 24 via the shaft 32 inserted into the guide slit 25 and moves along the guide slit 25. Engageably with bracket 24. The guide slit 25 may be provided in the backside frame 11, and the first end 22a of the second rod 22 may be engaged with the backside frame 11.

The second end 22b of the second rod 22 is fixed to the lumbar support plate 12 so as to be rotatable about an axis extending in the seat width direction through the second end 22b.

The guide slit 25 that guides the movement of the first end portion 22 a of the second rod 22 has a linear portion 40 and a curved portion 41 extending from the end of the linear portion 40. In the example shown in FIGS. 2 and 3, the first end 21a of the first rod 21 rotatably fixed to the bracket 24 is arranged on the extension line of the linear portion 40, and the curved portion 41 is the first rod. 21 extends from the first end portion 40a of the linear portion 40 located on the first end portion 21a side toward the lumbar support plate 12 side in an arc shape.

The drive unit 30 that drives the pair of links 20A and 20B includes a first connecting shaft 31, a second connecting shaft 32, a motor 33, and an elastic body 34.

The first connecting shaft 31 connects the first end portions 21a of the first rods 21 of the links 20A and 20B, respectively. The first connecting shaft 31 is arranged on the rotating shaft of the first end portion 21a that is rotatably fixed to the bracket 24, and is fixed to the first end portion 21a. The motor 33 is connected to the first connecting shaft 31 and rotates the first connecting shaft 31. When the first connecting shaft 31 is rotated by the motor 33, the first rods 21 of the links 20A and 20B rotate together with each other.

The second connecting shaft 32 connects the first end portions 22a of the second rods 22 of the links 20A and 20B, respectively. The end of the second connecting shaft 32 is inserted into the guide slit 25 of the bracket 24. The intersection portion 23 between the first rod 21 and the second rod 22 moves according to the rotation of the first rod 21, and the second rod 22 moves according to the movement of the intersection portion 23. At this time, the first end 22a of the second rod 22 moves along the guide slit 25 in which the second connecting shaft 32 is inserted.

The elastic body 34 is bridged between the first connecting shaft 31 and the second connecting shaft 32, and urges the movable second connecting shaft 32 toward the first connecting shaft 31. The elastic body 34 is, for example, a coil spring, but is not limited to the coil spring as long as it can elastically expand and contract.

FIG. 4 shows the operation of the links 20A, 20B and the lumbar support plate 12.

First, a state in which the second connecting shaft 32 is arranged at the second end 40b of the straight portion 40 of the guide slit 25, that is, the first end 22a (second end of the second rod 22 defined by the guide slit 25) In the range of motion of the connecting shaft 32), the first end portion 22a (second connecting shaft 32) of the second rod 22 is located at a position farthest from the first end portion 21a (first connecting shaft 31) of the first rod 21. It is supposed to be arranged.

When the first connecting shaft 31 is rotated by the motor 33, the first rod 21 is rotated about the first connecting shaft 31 in the arrow A direction. The second end 21b of the first rod 21 moves along the arc B passing through the second end 21b and centered on the first connecting shaft 31 in response to the rotation of the first rod 21. Further, the intersection portion 23 of the first rod 21 and the second rod 22 moves along the arc C passing through the intersection portion 23 with the first connecting shaft 31 as the center according to the rotation of the first rod 21. ..

Then, the second rod 22 moves according to the movement of the intersecting portion 23. At this time, the first end 22a of the second rod 22 moves along the guide slit 25 in which the second connecting shaft 32 is inserted. The second connecting shaft 32 moves from the second end portion 40b of the linear portion 40 of the guide slit 25 to the first end portion 40a, and further, of the curved portion 41 extending from the first end portion 40a toward the lumbar support plate 12 side. Move to the end.

While the second connecting shaft 32 moves from the second end 40b of the straight portion 40 of the guide slit 25 to the end of the curved portion 41, the second end 21b of the first rod 21 and the second end of the second rod 22. 22b are both displaced forward of the seat, and the lumbar support plate 12 is pushed out. Further, the second end portion 21b of the first rod 21 that supports the lower portion of the lumbar support plate 12 is displaced relatively much toward the front of the seat, and the backrest surface of the seat back 3 is pushed along with the extrusion of the lumbar support plate 12. The inclination of the lumbar support plate 12 with respect to is also changed.

Assuming that the inclination of the lumbar support plate 12 changes when the second connecting shaft 32 moves along the curved portion 41 of the guide slit 25 and that the second connecting shaft 32 moves along the extension of the straight portion 40 of the guide slit 25. Comparing the change in the inclination of the lumbar support plate 12 with the same rotation angle θ of the first rod 21, the change in the inclination of the lumbar support plate 12 when the second connecting shaft 32 moves along the curved portion 41. Becomes relatively large. That is, by providing the linear portion 40 and the curved portion 41 in the guide slit 25, the change in the pressing force can be emphasized as compared with the case where the entire guide slit 25 is formed in a linear shape, and the lumbar vertebra of the occupant is effective. Supportive.

In addition, in this example, the first rods 21 of the links 20A and 20B are connected by the first connecting shaft 31, and the first connecting shaft 31 is rotated by the motor 33, so that the first rods 21 of the links 20A and 20B are connected. Since the 1 rods 21 rotate in conjunction with each other, it is advantageous in reducing the cost and weight of the seat 1 as compared with the case where a motor is provided for each first rod 21.

Note that the lumbar support plate 12 is loaded while the seated person is leaning against the seat back 3, and the first rod 21 makes the lumbar support plate 12 stand still or push out against the load. A corresponding torque is required to rotate the first connecting shaft 31, which is the rotating shaft of the first rod 21, but in this example, there is elasticity between the first connecting shaft 31 and the second connecting shaft 32. The body 34 (see FIG. 3) is bridged, part of the torque required for the rotation of the first connecting shaft 31 is covered by the elastic body 34, and the load on the motor 33 is reduced. As a result, a small motor can be used as the motor 33, which is advantageous in reducing the cost and weight of the seat 1.

Here, the distance from the first end 21a of the first rod 21 to the intersecting portion 23 is L1a, the distance from the second end 21b of the first rod 21 to the intersecting portion 23 is L1b, and the distance of the second rod 22 is The distance from the first end 22a to the intersecting portion 23 is L2a, the distance from the second end 22b of the second rod 22 to the intersecting portion 23 is L2b, and preferably set to L2a/L1a=L2b/L1b, More preferably, L1a=L2a=L1b=L2b is set.

When L2a/L1a=L2b/L1b, as shown in FIG. 5, while the second connecting shaft 32 moves along the linear portion 40 of the guide slit 25, the lumbar support plate 12 may move the first rod 21 of the first rod 21. It is extruded while maintaining a state substantially parallel to a straight line D connecting the end portion 21a and the first end portion 22a of the second rod 22. That is, the lumbar support plate 12 is pushed out while keeping the inclination of the seat back 3 with respect to the backrest surface constant. On the other hand, while the second connecting shaft 32 moves along the curved portion 41 of the guide slit 25, the lumbar support plate 12 is pushed out while changing the inclination of the seat back 3 with respect to the backrest surface. Thereby, the change in the pressing force can be further emphasized, and the lumbar spine of the seated person can be effectively supported.

Then, when L1a=L2a=L1b=L2b, as shown in FIG. 6, while the second connecting shaft 32 moves along the linear portion 40 of the guide slit 25, the lumbar support plate 12 moves toward the first rod 21. It is kept substantially parallel to the straight line D connecting the first end portion 21a and the first end portion 22a of the second rod 22, and is pushed out without being displaced in the direction parallel to the straight line D. Thereby, the pressing force can be changed while keeping the pressing portion constant.

Up to this point, the guide slit 25 has been described as having the curved portion 41 extending from the first end portion 40a of the linear portion 40. However, as shown in FIG. 7, the guide slit 25 has the second end portion of the linear portion 40. It may have a curved portion 42 extending from 40b. The curved portion 42 extends in an arc shape from the second end portion 40b of the straight portion 40 toward the side opposite to the lumbar support plate 12 side.

While the second connecting shaft 32 moves from the straight portion 40 to the end of the curved portion 42, both the second end portion 21b of the first rod 21 and the second end portion 22b of the second rod 22 are displaced rearward of the seat, The lumbar support plate 12 is retracted. Further, the second end portion 21b of the first rod 21 that supports the lower portion of the lumbar support plate 12 is relatively displaced to the rear side of the seat, and when the lumbar support plate 12 is retracted, the backrest surface of the seat back 3 is formed. The inclination of the lumbar support plate 12 with respect to is also changed.

The change in the inclination of the lumbar support plate 12 when the second connecting shaft 32 moves along the curved portion 42 and the inclination of the lumbar support plate 12 assuming that the second connecting shaft 32 moves along the extension line of the straight portion 40. Comparing the change with the same rotation angle θ of the first rod 21, the change in the inclination of the lumbar support plate 12 when the second connecting shaft 32 moves along the curved portion 41 becomes relatively large. That is, by providing the linear portion 40 and the curved portion 42 in the guide slit 25, the change in the pressing force can be emphasized, and the lumbar vertebra of the seated person can be more effectively compared with the case where the entire guide slit 25 is formed in a linear shape. Supportive.

The change in the inclination of the lumbar support plate 12 when the second connecting shaft 32 moves along the curved portions 41 and 42 of the guide slit 25 can be appropriately set depending on the shapes of the curved portions 41 and 42. For example, as shown in FIG. 8, the curved portion 41 may have a shape in which the center of curvature O of the curved portion 41 is located on the lumbar support plate 12 side with respect to the straight line E connecting the start end and the end of the curved portion 41, As shown in FIG. 9, the center of curvature O of the curved portion 41 may be located on the side opposite to the lumbar support plate 12 side with respect to the straight line E. Further, the curved portions 41 and 42 are not limited to the arc shape having a constant radius of curvature, and may have a shape in which the radius of curvature changes.

FIG. 10 shows another example of the drive unit that drives the pair of links 20A and 20B for explaining the embodiment of the present invention.

The drive unit 50 shown in FIG. 10 includes a first connecting shaft 51, a second connecting shaft 52, a lead screw 53, and a motor 54.

The first connecting shaft 51 connects the first end portions 21a of the first rods 21 of the links 20A and 20B, respectively, and is rotatable with respect to the first end portion 21a. The first connecting shaft 51 is arranged on the rotation axis of the first end 21a. The second connecting shaft 52 connects the first end portions 22a of the second rods 22 of the links 20A and 20B, respectively, and is rotatable with respect to the first end portion 22a. The end of the second connecting shaft 52 is inserted into the guide slit 25 of the bracket 24. The first end 22a of the second rod 22 moves along the guide slit 25 in which the second connecting shaft 52 is inserted.

The lead screw 53 is bridged between the first connecting shaft 51 and the second connecting shaft 52. The first connecting shaft 51 has a screw hole penetrating the first connecting shaft 51 in the radial direction of the first connecting shaft 51, and the lead screw 53 is screwed into the screw hole of the first connecting shaft 51. The second connecting shaft 52 has a bearing hole that rotatably supports one end of the lead screw 53. The bearing hole may be provided in the first connecting shaft 51 and the screw hole may be provided in the second connecting shaft 52.

The motor 54 is fixed to the second connecting shaft 52 that rotatably supports one end of the lead screw 53. Then, the motor 54 meshes with the lead screw 53 via the gear 55 to rotate the lead screw 53.

FIG. 11 shows the operation of the drive unit 50, the pair of links 20A and 20B driven by the drive unit 50, and the lumbar support plate 12.

When the lead screw 53 is rotated by the motor 54, the lead screw 53 is fed to the first connecting shaft 51, and the distance between the first connecting shaft 51 and the second connecting shaft 52 is narrowed. By reducing the distance between the first connecting shaft 51 and the second connecting shaft 52, the intersection 23 between the first rod 21 and the second rod 22 moves, and the first rod 21 moves in accordance with the movement of the intersection 23. Rotates around the first connecting shaft 51 in the direction of arrow A, and the second rod 22 also moves. In the movement of the second rod 22, the first end portion 22a of the second rod 22 moves along the guide slit 25 in which the second connecting shaft 52 is inserted.

While the second connecting shaft 52 moves from the straight portion 40 of the guide slit 25 to the end of the curved portion 41, the second end portion 21b of the first rod 21 and the second end portion 22b of the second rod 22 are both seat fronts. And the lumbar support plate 12 is pushed out. Further, the second end portion 21b of the first rod 21 that supports the lower portion of the lumbar support plate 12 is displaced relatively much toward the front of the seat, and the backrest surface of the seat back 3 is pushed along with the extrusion of the lumbar support plate 12. The inclination of the lumbar support plate 12 with respect to is also changed. The movement of the lumbar support plate 12 shown in FIG. 12 is the same as the movement of the lumbar support 12 shown in FIG. 4, and the guide slit 25 is provided with the straight line portion 40 and the curved portion 41. The change in the pressing force is emphasized as compared with the case where the whole is formed linearly.

In the present example, the pair of links 20A and 20B are interlocked with each other by the one lead screw 53 bridged between the first connecting shaft 51 and the second connecting shaft 52 and the motor 54 that rotates the lead screw 53. This is advantageous in reducing the cost and weight of the seat 1 as compared with the case where the lead screw is provided for each of the links 20A and 20B.

Although the present invention has been described above by taking the seat 1 installed in a vehicle such as an automobile as an example, the present invention is also applicable to a seat installed in a vehicle other than a vehicle such as an aircraft or a ship.

As described above, as described above, the vehicle seat disclosed in the present specification is provided symmetrically with the lumbar support plate arranged along the backrest surface of the seat back and with a space in the seat width direction, and A pair of links for connecting the lumbar support plate to the seat back frame and a drive unit for driving the pair of links are provided, and the pair of links are arranged between the lumbar support plate and the seat back frame. A first rod and a second rod, and the first rod and the second rod are disposed so as to intersect with each other and are rotatably coupled at the intersection, and both ends of the first rod are provided. A first end of the portion located on the seat back frame side is rotatably fixed to the seat back frame or a bracket attached to the seat back frame, and a second end of the first rod is A first end of the second rod that is engaged with the lumbar support plate so as to be movable along the lumbar support plate and that is located on the seat back frame side is one of the two ends of the second rod. The seat back frame or the bracket is movably engaged with a guide slit provided on the bracket, and the second end of the second rod is rotatably fixed to the lumbar support plate. The first end of the second rod moves along the guide slit when the pair of links is driven by the drive unit, and the guide slit is a linear portion and a linear portion. A curved portion extending from at least one of the both ends.

Further, in the vehicle seat disclosed in the present specification, the first end portion of the first rod is arranged on an extension line of the straight line portion of the guide slit, and the guide slit is the straight line portion. A first curved portion extending from the first end portion located on the first end portion side of the first rod toward the lumbar support plate side, and/or the second end portion of the linear portion, It has a 2nd curve part extended toward the opposite side to the said lumbar support plate side.

Further, the vehicle seat disclosed in the present specification has a distance from the first end of the second rod to the intersection with respect to a distance from the first end of the first rod to the intersection. The ratio is equal to the ratio of the distance from the second end of the second rod to the intersection to the distance from the second end of the first rod to the intersection.

Further, the vehicle seat disclosed in the present specification has a distance from the first end portion of the first rod to the intersecting portion and a distance from the second end portion of the first rod to the intersecting portion. And the distance from the first end of the second rod to the intersection is equal to the distance from the second end of the second rod to the intersection.

In the vehicle seat disclosed in the present specification, the drive unit includes a first connecting shaft that connects the first end portions of the first rods of the pair of links, and the first connecting shaft. And a motor for rotating the first connecting shaft, the first connecting shaft being arranged on a rotation axis of the first end of the first rod and being fixed to the first end of the first rod. ..

Further, in the vehicle seat disclosed in the present specification, the drive unit includes a second connecting shaft that connects the first end portions of the second rods of the pair of links, and the first connecting shaft. And an elastic body bridged between the second connection shaft and the second connection shaft.

Further, in the vehicle seat disclosed in the present specification, the drive unit connects the first end portions of the first rods of the pair of links to each other and rotatably connects the first rod of the first rod. A first connecting shaft supported by one end and the first ends of the second rods of the pair of links, and rotatably supported by the first end of the second rod. A second connecting shaft, a lead screw bridged between the first connecting shaft and the second connecting shaft, and a motor for rotating the lead screw. One of the second connecting shafts rotatably supports the lead screw, and the other shaft is screwed with the lead screw.

1 Vehicle Seat 2 Seat Cushion 3 Seat Back 10 Seat Back Frame 11 Back Side Frame 12 Lumbar Support Plate 20A Link 20B Link 21 First Rod 21a First End 21b of First Rod Second End 22b of First Rod 22 2 rod 22a 1st end part 22b of 2nd rod 2nd end part 23 of 2nd rod 23 intersection part 24 bracket 25 guide slit 30 drive part 31 1st connecting shaft 32 2nd connecting shaft 33 motor 34 elastic body 40 of guide slit Straight part 40a First end part 40b of straight part Second end part of straight part 41 Curved part of guide slit 42 Curved part of guide slit 50 Drive part 51 First connecting shaft 52 Second connecting shaft 54 Motor 55 Gear

Claims (7)

A lumbar support plate arranged along the backrest surface of the seat back,
A pair of links that are provided symmetrically with a space in the seat width direction and connect the lumbar support plate to the seat back frame,
A drive unit that drives the pair of links,
Equipped with
The pair of links each have a first rod and a second rod bridged between the lumbar support plate and the seat back frame,
The first rod and the second rod are arranged so as to intersect with each other and are rotatably coupled at the intersecting portion,
A first end of the both ends of the first rod located on the seat back frame side is rotatably fixed to the seat back frame or a bracket attached to the seat back frame. Has a second end movably engaged with the lumbar support plate along the lumbar support plate,
A first end of the both ends of the second rod, which is located on the seat back frame side, is movably connected to the seat back frame or the bracket along a guide slit provided in the seat back frame or the bracket. Engaged, the second end of the second rod is rotatably fixed to the lumbar support plate,
By driving the pair of links by the drive unit, the first end of the second rod moves along the guide slit,
The said guide slit is a vehicle seat which has a linear part and a curved part extended from at least one end part of the both ends of the said linear part. The vehicle seat according to claim 1, wherein:
The first end portion of the first rod is arranged on an extension line of the linear portion of the guide slit,
The guide slit is
Of the both ends of the linear portion, a first curved portion extending from the first end portion located on the first end portion side of the first rod toward the lumbar support plate side, and/or the second linear portion. A vehicle seat having a second curved portion extending from an end portion to a side opposite to the lumbar support plate side. The vehicle seat according to claim 2, wherein:
From the ratio of the distance from the first end of the second rod to the intersection to the distance from the first end of the first rod to the intersection, and from the second end of the first rod. A vehicle seat in which the ratio of the distance from the second end of the second rod to the intersection to the distance to the intersection is equal. The vehicle seat according to claim 3, wherein:
A distance from the first end of the first rod to the intersection, a distance from the second end of the first rod to the intersection, and the first end of the second rod to the intersection. A vehicle seat in which the distance to the intersection is equal to the distance from the second end of the second rod to the intersection. The vehicle seat according to any one of claims 1 to 4,
The drive unit is
A first connecting shaft that connects the first ends of the first rods of the pair of links;
A motor for rotating the first connecting shaft,
Have
The vehicle seat according to claim 1, wherein the first connecting shaft is disposed on a rotation axis of the first end portion of the first rod and is fixed to the first end portion of the first rod. The vehicle seat according to claim 5, wherein:
The drive unit is
A second connecting shaft that connects the first ends of the second rods of the pair of links;
An elastic body bridged between the first connecting shaft and the second connecting shaft;
Vehicle seat having. The vehicle seat according to any one of claims 1 to 4,
The drive unit is
A first connecting shaft that connects the first ends of the first rods of each of the pair of links and is rotatably supported by the first ends of the first rods;
A second connecting shaft that connects the first ends of the second rods of the pair of links and is rotatably supported by the first ends of the second rods;
A lead screw bridged between the first connecting shaft and the second connecting shaft;
A motor for rotating the lead screw,
Have
One of the first connecting shaft and the second connecting shaft rotatably supports the lead screw, and the other shaft is screwed to the lead screw.

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