Reclining device for vehicle seat

1 . A reclining device for a vehicle seat, the reclining device comprising:

a rotary bracket having a center portion thereof rotatably connected to a first frame and having a first locking section and a second locking section connected to the first locking section; and

a cam configured to rotate about a center portion thereof which is connected to the first frame and having a locking portion disposed at one end thereof and disposed in the first locking section or the second locking section to be locked,

wherein a second pressure angle at which the locking portion is locked in the second locking section is smaller than a first pressure angle at which the locking portion is locked in the first locking section, and

wherein the rotary bracket further comprises:

a first support protrusion disposed on one surface of the rotary bracket, directed toward the first frame, defined at an interval from the center portion of the rotary bracket, and configured to be inserted into a first long hole of the first frame; and

a second support protrusion disposed on the one surface of the rotary bracket, directed toward the first frame, defined between the center portion of the rotary bracket and the first support protrusion, and configured to be inserted into a second long hole of the first frame.

2 . The reclining device of claim 1 , wherein the first pressure angle is in a range of 6 to 12 degrees, and the second pressure angle is in a range of 0 to 5 degrees.

3 . The reclining device of claim 1 , wherein the first and second pressure angles are angles between a direction of a load of the rotary bracket applied toward the cam and a direction of a reaction force of the cam.

4 . The reclining device of claim 3 , wherein the load of the rotary bracket is applied along a normal line that is perpendicular to a tangential line of the first and second locking sections, and the reaction force of the cam is applied along a straight line that connects two locking points at which the center portion of the cam meets the tangential line and the normal line.

5 . The reclining device of claim 4 , wherein a disc is coupled to a connection part between a second frame and the first frame connected to a seat cushion, and the rotary bracket is disposed inside the first frame and positioned between the disc and the cam.

6 . The reclining device of claim 5 , wherein when an external impact is applied to the disc, a rotational force of the disc is transmitted to the cam through the rotary bracket, and the locking portion of the cam disposed in the first locking section separates from the first locking section and engages with a locking point of the second locking section to be locked.

7 . The reclining device of claim 5 , wherein the rotary bracket comprises:

an insertion protrusion configured to restrict a rotation of the disc by being inserted into an accommodation groove defined in the disc; and

a release groove defined as a recessed groove connected to the second locking section.

8 . The reclining device of claim 7 , wherein the center portion of the rotary bracket is rotatably connected to the first frame by a first hinge shaft, and the center portion of the cam and a center portion of a lever are rotatably connected to the first frame by a second hinge shaft.

9 . The reclining device of claim 8 , wherein the lever has an assembling hole, an assembling protrusion of the cam is configured to be inserted into the assembling hole, and the assembling protrusion is defined on one surface of the cam directed toward the lever.

10 . The reclining device of claim 8 , wherein when a cable connected to the lever is pulled, the cam rotates about the center portion of the cam in a release direction together with the lever, and the locking portion, which engages with the first locking section in a locking state, passes over the second locking section and is inserted into the release groove, such that the insertion protrusion of the rotary bracket, which is inserted into the accommodation groove of the disc, separates from the accommodation groove, while the second frame connected to a seatback rotates in a folding direction together with the disc, and the seatback is folded.