Vehicle seat

1. A vehicle seat, comprising:

a seat cushion;

a seat back which includes left and right side frames;

a pressure-receiving member disposed rearwardly of an occupant between the left and right side frames; and

a rocking mechanism configured to cause a left side or a right side of the pressure-receiving member to move frontward and rearward,

wherein the pressure-receiving member includes a pressure-receiving portion configured to support a back of the occupant, and a pair of support portions provided at left and right end portions of the pressure-receiving member and extending in a leftward-and-frontward direction and in a rightward-and-frontward direction, respectively, to support upper body side regions of the occupant,

wherein the rocking mechanism includes:

a pressing member configured to press the left or right end portion of the pressure-receiving member in a front-rear direction; and

an actuator configured to actuate the pressing member,

wherein the actuator is disposed rearwardly of a corresponding support portion, to overlap the support portion as viewed in the front-rear direction, and

the actuator has an axis, the actuator being configured to cause the pressing member to pivot about the axis.

2. The vehicle seat according to claim 1 , wherein the actuator is disposed at a laterally inner side of a corresponding side frame.

3. The vehicle seat according to claim 1 , wherein the actuator has an elongated shape of which a longitudinal direction is arranged along a corresponding side frame.

4. The vehicle seat according to claim 1 , wherein each support portion is disposed laterally opposite to a corresponding side frame, and

wherein the actuator is disposed between the support portion and the corresponding side frame in a lateral direction.

5. The vehicle seat according to claim 1 , wherein a front end portion of each support portion extends along an outer surface of the actuator in a laterally outside direction.

6. The vehicle seat according to claim 1 , wherein each support portion includes a projection protruding rearward, and

wherein the actuator is separate from the projection.

7. The vehicle seat according to claim 6 , wherein the pressure-receiving member further includes a connecting wire configured to support the pressure-receiving portion and the support portions from rear sides thereof, an end portion of the connecting wire being connected with the pressing member,

wherein the pressure-receiving portion and the support portions include engageable claws configured to engage with the connecting wire whereby the pressure-receiving member is supported by the connecting wire, and

wherein an engageable claw provided in each support portion is formed integrally with the projection in a single-piece construction.

8. The vehicle seat according to claim 7 , wherein the engageable claw provided in each support portion includes a base portion extending rearward from the projection, and a claw portion extending from a rear end of the base portion downward beyond a lower edge of the projection.

9. The vehicle seat according to claim 6 , wherein the projection includes a first portion and a second portion that are arranged separate from each other, and

wherein the pressing member is disposed between the first portion and the second portion.

10. The vehicle seat according to claim 9 , wherein the pressing member is configured to contact a portion of a corresponding support portion between the first portion and the second portion of the projection at least when the pressure-receiving member is in a frontmost position.

11. The vehicle seat according to claim 6 , wherein the pressing member is configured to contact the projection.

12. The vehicle seat according to claim 6 , wherein the pressure-receiving portion and the support portions are formed integrally in a single-piece construction, and

wherein the pressure-receiving portion includes a second projection protruding rearward, the second projection being continuous with the projection provided in each support portion.

13. The vehicle seat according to claim 1 , wherein the pressure-receiving member further includes a connecting wire configured to support the pressure-receiving portion from a rear side thereof, an end portion of the connecting wire being connected with the pressing member,

wherein the pressure-receiving portion includes an engageable claw configured to engage with the connecting wire whereby the pressure-receiving member is supported by the connecting wire, and

wherein the engageable claw is provided at a laterally outer end portion of the pressure-receiving portion.

14. The vehicle seat according to claim 1 , wherein the actuator includes a motor.

15. The vehicle seat according to claim 14 , wherein the rocking mechanism further includes a biasing member configured to bias the pressing member toward an initial position thereof.

16. The vehicle seat according to claim 1 , wherein the pressing member is arranged to contact a corresponding support portion.

17. The vehicle seat according to claim 16 , wherein the pressure-receiving member further includes a connecting wire configured to support the pressure-receiving portion from a rear side thereof, an end portion of the connecting wire being connected with the pressing member.

18. The vehicle seat according to claim 16 , wherein the pressing member is configured to contact the support portion at least when the pressure-receiving member is in a frontmost position.

19. A vehicle seat comprising:

a seat cushion;

a seat back which includes left and right side frames;

a pressure-receiving member disposed between the left and right side frames, the pressure-receiving member being configured to support an upper body of an occupant; and

a rocking mechanism configured to cause a left side or a right side of the pressure-receiving member to move frontward and rearward,

wherein the rocking mechanism includes:

a pressing member configured to press a left or right end portion of the pressure-receiving member in a front-rear direction; and

an actuator configured to actuate the pressing member, and

wherein the actuator is disposed to overlap the left or right end portion of the pressure-receiving member as viewed in the front-rear direction, and

the actuator has an axis, the actuator being configured to cause the pressing member to pivot about the axis.

20. A vehicle seat, comprising:

a seat cushion;

a seat back which includes left and right side frames;

a pressure-receiving member disposed rearwardly of an occupant between the left and right side frames; and

a rocking mechanism configured to cause a left side or a right side of the pressure-receiving member to move frontward and rearward,

wherein the pressure-receiving member includes a pressure-receiving portion configured to support a back of the occupant, and a pair of support portions provided at left and right end portions of the pressure-receiving member and extending in a leftward-and-frontward direction and in a rightward-and-frontward direction, respectively, to support upper body side regions of the occupant,

wherein the rocking mechanism includes:

a pressing member configured to press the left or right end portion of the pressure-receiving member in a front-rear direction; and

an actuator configured to actuate the pressing member,

wherein the actuator is disposed rearwardly of a corresponding support portion, to overlap the support portion as viewed in the front-rear direction,

the actuator includes a motor, and

the rocking mechanism further includes a biasing member configured to bias the pressing member toward an initial position thereof.