Occupant posture adjusting device of vehicle seat

1. An occupant posture adjusting device of a vehicle seat including a seat cushion and a seat back connected to a rear end of the seat cushion, the occupant posture adjusting device comprising:

a plate-shaped bottom support member pivotably supported by the seat cushion via a pivot shaft extending laterally at a position directly under a hip point of an occupant seated in the seat, such that the bottom support member is capable of supporting thighs and ischia of the occupant from below;

a plate-shaped lower part support member pivotably supported by the seat back via a pivot shaft extending laterally at a position lower than an intermediate portion of the seat back with respect to a vertical direction, such that the lower part support member is capable of supporting at least a pelvis of the occupant from behind;

a plate-shaped upper part support member pivotably supported by the seat back via a pivot shaft extending laterally at a position higher than the intermediate portion of the seat back with respect to the vertical direction, such that the upper part support member is capable of supporting at least scapulae of the occupant from behind;

first to third drive devices configured to drive the bottom support member, the lower part support member, and the upper part support member, respectively; and

a control device configured to control the first to third drive devices,

wherein the pivot shaft of the bottom support member is configured to be positioned between front of the thighs and the ischia of the seated occupant, the bottom support member has a front part configured to support the thighs and a rear part configured to support the ischia and is configured to take a first state in which the front part is raised and the rear part is lowered and a second state in which the rear part is raised and the front part is lowered.

2. The occupant posture adjusting device according to claim 1 , further comprising front and rear first body pressure sensors associated with the bottom support member, the front and rear first body pressure sensors being disposed at positions corresponding to one of the thighs and one of ischia of the seated occupant, respectively, wherein the control device is configured to control the first drive device based on a comparison between outputs from the front and rear first body pressure sensors.

3. The occupant posture adjusting device according to claim 2 , further comprising upper and lower second body pressure sensors associated with the lower part support member, the upper and lower second body pressure sensors being disposed at positions corresponding to a waist and one of ilia of the seated occupant, respectively, wherein the control device is configured to control the second drive device based on a comparison between outputs from the upper and lower second body pressure sensors.

4. The occupant posture adjusting device according to claim 3 , wherein the control device is configured to operate the second drive device subsequent to operation of the first drive device.

5. The occupant posture adjusting device according to claim 4 , further comprising at least one third body pressure sensor associated with the upper part support member, the at least one third body pressure sensor being disposed at a position corresponding to one of the scapulae of the seated occupant, wherein the control device is configured to control the third drive device based on a comparison between an output from the third body pressure sensor and the output from the upper second body pressure sensor.

6. The occupant posture adjusting device according to claim 5 , wherein the control device is configured to operate the third drive device subsequent to operation of the second drive device.

7. The occupant posture adjusting device according to claim 6 , wherein the control device is configured to cause the first drive device and the second drive device to maintain operation states thereof before activating the third drive device.

8. The occupant posture adjusting device according to claim 2 , wherein the comparison is performed to determine whether a difference between pressures indicated by the outputs exceeds a predetermined threshold value.

9. The occupant posture adjusting device according to claim 2 , wherein the control device includes a manual input device configured to receive input from the occupant, and the comparison is performed based on a mode selected by the occupant using the manual input device.

10. An occupant posture adjusting device of a vehicle seat including a seat cushion and a seat back connected to a rear end of the seat cushion, the occupant posture adjusting device comprising:

a plate-shaped bottom support member pivotably supported by the seat cushion via a pivot shaft extending laterally at a position directly under a hip point of an occupant seated in the seat, such that the bottom support member is capable of supporting at least thighs of the occupant from below;

a plate-shaped lower part support member pivotably supported by the seat back via a pivot shaft extending laterally at a position lower than an intermediate portion of the seat back with respect to a vertical direction, such that the lower part support member is capable of supporting at least a pelvis of the occupant from behind;

a plate-shaped upper part support member pivotably supported by the seat back via a pivot shaft extending laterally at a position higher than the intermediate portion of the seat back with respect to the vertical direction, such that the upper part support member is capable of supporting at least scapulae of the occupant from behind;

first to third drive devices configured to drive the bottom support member, the lower part support member, and the upper part support member, respectively;

a control device configured to control the first to third drive devices;

front and rear first body pressure sensors associated with the bottom support member, the front and rear first body pressure sensors being disposed at positions corresponding to one of the thighs and one of ischia of the seated occupant, respectively; and

upper and lower second body pressure sensors associated with the lower part support member, the upper and lower second body pressure sensors being disposed at positions corresponding to a waist and one of ilia of the seated occupant, respectively,

wherein the control device is configured to control the first drive device based on a comparison between outputs from the front and rear first body pressure sensors and control the second drive device based on a comparison between outputs from the upper and lower second body pressure sensors.

11. The occupant posture adjusting device according to claim 10 , wherein the control device is configured to operate the second drive device subsequent to operation of the first drive device.

12. The occupant posture adjusting device according to claim 11 , further comprising at least one third body pressure sensor associated with the upper part support member, the at least one third body pressure sensor being disposed at a position corresponding to one of the scapulae of the seated occupant, wherein the control device is configured to control the third drive device based on a comparison between an output from the third body pressure sensor and the output from the upper second body pressure sensor.

13. The occupant posture adjusting device according to claim 12 , wherein the control device is configured operate the third drive device subsequent to operation of the second drive device.

14. The occupant posture adjusting device according to claim 13 , wherein the control device is configured to cause the first drive device and the second drive device to maintain operation states thereof before activating the third drive device.

15. The occupant posture adjusting device according to claim 10 , wherein the comparison is performed to determine whether a difference between pressures indicated by the outputs exceeds a predetermined threshold value.

16. The occupant posture adjusting device according to claim 10 , wherein the control device includes a manual input device configured to receive input from the occupant, and the comparison is performed based on a mode selected by the occupant using the manual input device.

17. An occupant posture adjusting device of a vehicle seat including a seat cushion and a seat back connected to a rear end of the seat cushion, the occupant posture adjusting device comprising:

a plate-shaped bottom support member pivotably supported by the seat cushion via a pivot shaft extending laterally at a position directly under a hip point of an occupant seated in the seat, such that the bottom support member is capable of supporting at least thighs of the occupant from below;

a plate-shaped lower part support member pivotably supported by the seat back via a pivot shaft extending laterally at a position lower than an intermediate portion of the seat back with respect to a vertical direction, such that the lower part support member is capable of supporting at least a pelvis of the occupant from behind;

a plate-shaped upper part support member pivotably supported by the seat back via a pivot shaft extending laterally at a position higher than the intermediate portion of the seat back with respect to the vertical direction, such that the upper part support member is capable of supporting at least scapulae of the occupant from behind;

first to third drive devices configured to drive the bottom support member, the lower part support member, and the upper part support member, respectively;

a control device configured to control the first to third drive devices; and

front and rear first body pressure sensors associated with the bottom support member, the front and rear first body pressure sensors being disposed at positions corresponding to one of the thighs and one of ischia of the seated occupant, respectively,

wherein the control device is configured to control the first drive device based on a comparison between outputs from the front and rear first body pressure sensors, the comparison is performed to determine whether a difference between pressures indicated by the outputs exceeds a predetermined threshold value.

18. The occupant posture adjusting device according to claim 17 , wherein the control device includes a manual input device configured to receive input from the occupant, and the comparison is performed based on a mode selected by the occupant using the manual input device.