The present application is a 35 U.S.C. 371 Patent Application of PCT Application No. PCT/CN2018/098499, filed on Aug. 3, 2018, which claims the priority to Chinese Patent Application No. 201810806392.9, titled “VEHICLE SEAT AND ANGLE ADJUSTMENT DEVICE THEREOF”, and the priority to Chinese Patent Application No. 201821164386.X, titled “VEHICLE SEAT AND ANGLE ADJUSTMENT DEVICE THEREOF”, filed with the China National Intellectual Property Administration on Jul. 20, 2018, both of which are incorporated herein by reference in their entireties.

FIELD

The present application relates to the technical field of mechanical design, and in particular to a vehicle seat and an angle adjustment device thereof.

BACKGROUND

When a vehicle seat is in use, it is necessary to adjust the angle of a seat back relative to a seat for meeting the requirements of different users, so as to improve the seating comfort of the seat.

At present, an existing vehicle angle adjustment device includes a ratchet wheel fixedly connected with the seat back and provided with internal teeth, and a sliding groove plate fixed with the seat and provided with a sliding groove. Multiple sliding blocks with external teeth are arranged on the sliding groove plate, and each sliding block is controlled to extend in the radial direction through an expansion and contraction mechanism, so as to realize the engagement of the internal teeth of the ratchet wheel and the external teeth of the sliding block. Meanwhile, a return spring is arranged between the sliding blocks, and both ends of each return spring in the axial direction respectively abut against a flange on the sliding groove plate and the expansion and contraction mechanism, so as to realize the synchronous expansion and contraction of each sliding block in the radial direction.

In the above angle adjustment process, when the seat is locked, the radially extending locking torque of the sliding block is provided by the return spring. Correspondingly, when the seat is unlocked, the external unlocking torque also needs to overcome the locking torque to achieve unlocking. Generally, in order to ensure the locking reliability, the locking torque of the return spring is usually set to a relatively large value, which causes an unlocking torque to be also relatively large when the unlocking is performed, thus making the people uncomfortable.

In view of this, how to provide an angle adjustment device that can improve the comfort of unlocking while ensuring high locking reliability is a technical problem to be solved by those skilled in the art.

SUMMARY

To solve the above technical problem, an object of the present application is to provide an angle adjustment device, including an unlocking cam, a ratchet wheel provided with internal teeth and multiple sliding blocks distributed along the circumferential direction and provided with external teeth. The angle adjustment device further includes multiple expansion and contraction blocks corresponding to the multiple sliding blocks, and the multiple expansion and contraction blocks can drive the multiple sliding blocks to move outwards in radial directions, so as to allow the internal teeth to be meshed with the external teeth; a second elastic piece is arranged between adjacent expansion and contraction blocks, and two ends of the second elastic piece along the deformation direction are respectively connected with the unlocking cam and the multiple expansion and contraction blocks.

The expansion and contraction blocks are used for driving the multiple sliding block to extend out in radial directions, so as to realize the engagement of the multiple sliding block and the ratchet wheel. When the unlocking cam rotates in the unlocking direction, the multiple sliding blocks can be separated from the ratchet wheel. When the angle adjustment device is unlocked, an unlocking torque needs to be provided from the outside to drive the unlocking cam to rotate in the unlocking direction, and only when the unlocking torque reaches a certain value, can the unlocking cam be driven to overcome the locking force to rotate in the unlocking direction.

In the present application, when the unlocking cam rotates in the unlocking direction, the second elastic piece which is in a compressed state and connected with the unlocking cam and the multiple expansion and contraction blocks can act on the unlocking cam and the multiple expansion and contraction blocks. Moreover, the elastic force of the second elastic piece on the unlocking cam faces the unlocking direction, and the elastic force on the multiple expansion and contraction blocks faces the locking direction. Therefore, the elastic force of the second elastic piece on the unlocking cam in the unlocking direction can reduce the unlocking torque that needs to be provided by the outside world to act on the unlocking cam when the angle adjustment device is unlocked. Thus, the angle adjustment device can realize the unlocking process with only a small unlocking torque, and the comfort when the angle adjustment device is unlocked is improved.

Meanwhile, in the locking process, after the unlocking torque disappears, the second elastic piece can provide enough elastic force to drive the expansion and contraction block to rotate, thus ensuring the reliability of the locking process. When a relatively large number of sliding blocks are provided, it still has high unlocking comfort and locking reliability.

Preferably, the angle adjustment device further includes a first elastic piece and a sliding groove plate that rotates relative to the ratchet wheel. One end of the first elastic piece is connected to the sliding groove plate, and the other end of the first elastic piece is directly or indirectly connected to the unlocking cam so as to allow the torque of the unlocking cam to be transmitted.

Preferably, the angle adjustment device further includes a central shaft, the unlocking cam has a central hole, the central shaft is matched with the central hole, and the central shaft can drive the unlocking cam to rotate in the unlocking direction when the central shaft rotates in the unlocking direction;

The first elastic piece is connected to the central shaft so as to be indirectly connected to the unlocking cam.

Preferably, the unlocking cam has multiple first protrusions, matching grooves are provided on the expansion and contraction blocks, and two ends of the second elastic piece along the deformation direction are respectively abutted against the corresponding first protrusions and the matching grooves.

Preferably, multiple mounting holes are provided on the unlocking cam, an upside down edge is provided on a side wall of each of the multiple mounting holes, and the upside down edge is the first protrusion.

Preferably, the expansion and contraction block has a second protrusion, the unlocking cam is provided with a groove, and two ends of the second elastic piece in the deformation direction respectively abut against the second protrusion and a side wall of the groove.

Preferably, the first elastic piece is a flat spiral spring, and an outer end of the flat spiral spring is fixed to the sliding groove plate, and an inner end of the flat spiral spring is fixed to the central shaft so as to allow the torque of the central shaft to be transmitted.

Preferably, the sliding groove plate is provided with a fixing column, an outer end of the first elastic piece is hooked with the fixing column, and when the central shaft drives the inner end of the first elastic piece to rotate in the unlocking direction, the fixing column can restrict the outer end of the first elastic piece from moving.

Preferably, a flange is provided on a middle part of the sliding groove plate, and the expansion and contraction block can move along an outer peripheral surface of the flange.

The flange is integrally formed with the sliding groove plate, or the flange is fixedly connected with the sliding groove plate.

Meanwhile, the present application further provides a vehicle seat, including a seat and a seat back, and further includes an angle adjustment device for adjusting the angle of the seat back relative to the seat. The angle adjustment device is the angle adjustment device described above.

