Vehicle seat reclining device

1. A vehicle seat reclining device comprising:

a first bracket;

a second bracket that rotates relative to the first bracket in positive and negative directions;

a cam that rotates or moves relative to the first bracket; and

a plurality of pawls moved in a radial direction of the first bracket and engaged with the second bracket by rotation or movement of the cam, wherein

each of the pawls is biased toward a radially outer side and moved in the radial direction in cooperation with the rotation or the movement of the cam,

a first pawl and a second pawl of the plurality of pawls each include a limitation portion that limits movement in the radial direction,

the second bracket includes

an outer circumferential wall including inner teeth that mesh with outer teeth of the pawls, and

a first pawl restriction portion and a second pawl restriction portion arranged respectively in correspondence with the first pawl and the second pawl to engage the corresponding limitation portions and restrict movement of the first pawl and the second pawl in the radial direction,

the second pawl restriction portion is located toward the positive direction and a radially inner side from the first pawl restriction portion,

negative direction ends of the first pawl restriction portion and the second pawl restriction portion are arranged to contact positive direction corners of the limitation portions of the first pawl and the second pawl when a rotation angle of the second bracket relative to the first bracket is a specified angle,

the first pawl restriction portion allows movement of the second pawl toward the radially outer side,

the first pawl restriction portion extends in the positive direction to the negative direction end of the second pawl restriction portion, and

the first pawl restriction portion restricts movement of the first pawl toward the radially outer side when the second bracket is located toward the negative direction from the specified angle and allows movement of the second pawl toward the radially outer side when the second bracket is located toward the positive direction from the specified angle.

2. The vehicle seat reclining device according to claim 1 , wherein

a third pawl of the pawls includes a limitation portion,

the second bracket further includes a third pawl restriction portion arranged in correspondence with the third pawl, wherein the third pawl restriction portion engages the limitation portion of the third pawl to restrict movement of the third pawl in the radial direction,

the third pawl restriction portion is located toward the positive direction and the radially inner side, at the same position in the radial direction, or at the radially outer side of the second pawl restriction portion, and

a negative direction end of the third pawl restriction portion is arranged to contact a positive direction corner of the limitation portion of the third pawl when the rotation angle of the second bracket relative to the first bracket is the specified angle.

3. A vehicle seat reclining device comprising:

a first bracket;

a second bracket that rotates relative to the first bracket in positive and negative directions;

a cam that rotates or moves relative to the first bracket; and

a plurality of pawls moved in a radial direction of the first bracket and engaged with the second bracket by rotation or movement of the cam, wherein

each of the pawls is biased toward a radially outer side and moved in the radial direction in cooperation with the rotation or the movement of the cam,

a first pawl and a second pawl of the plurality of pawls each include a limitation portion that limits movement in the radial direction,

the second bracket includes

an outer circumferential wall including inner teeth that mesh with outer teeth of the pawls, and

a first pawl restriction portion and a second pawl restriction portion arranged respectively in correspondence with the first pawl and the second pawl to engage the corresponding limitation portions and restrict movement of the first pawl and the second pawl in the radial direction,

the second pawl restriction portion is located toward the positive direction and a radially inner side from the first pawl restriction portion,

negative direction ends of the first pawl restriction portion and the second pawl restriction portion are arranged to contact positive direction corners of the limitation portions of the first pawl and the second pawl when a rotation angle of the second bracket relative to the first bracket is a specified angle,

the first pawl restriction portion allows movement of the second pawl toward the radially outer side,

a third pawl of the pawls includes a limitation portion,

the second pawl restriction portion extends in the positive direction, and

the second pawl restriction portion restricts movement of the second pawl toward the radially outer side when the second bracket is located toward the negative direction from the specified angle and allows movement of the third pawl toward the radially outer side when the second bracket is located toward the positive direction from the specified angle.

4. The vehicle seat reclining device according to claim 3 , wherein

the second bracket further includes a third pawl restriction portion arranged in correspondence with the third pawl, wherein the third pawl restriction portion engages the limitation portion of the third pawl to restrict movement of the third pawl in the radial direction,

the third pawl restriction portion is located toward the positive direction and the radially inner side of the second pawl restriction portion, and

a negative direction end of the third pawl restriction portion is arranged to contact a positive direction corner of the limitation portion of the third pawl when the rotation angle of the second bracket relative to the first bracket is the specified angle.

5. A vehicle seat reclining device comprising:

a first bracket;

a second bracket that rotates in positive and negative directions relative to the first bracket;

a cam that rotates or moves relative to the first bracket; and

a plurality of pawls that move in a radial direction of the first bracket in cooperation with rotation or movement of the cam to engage the second bracket, wherein

each of the pawls is biased toward a radially outer side and moved in the radial direction in cooperation with the rotation or the movement of the cam,

a first pawl and a second pawl of the plurality of pawls each include a limitation portion that limits movement in the radial direction,

the second bracket includes

an outer circumferential wall including inner teeth that mesh with outer teeth of the pawls, and

a first pawl restriction portion and a second pawl restriction portion respectively arranged in correspondence with the first pawl and the second pawl to engage the corresponding limitation portions and restrict movement of the first pawl and the second pawl in the radial direction,

the second pawl restriction portion is located toward the negative direction from the first pawl restriction portion,

negative direction ends of the first pawl restriction portion and the second pawl restriction portion are arranged to contact positive direction corners of the limitation portions of the first pawl and the second pawl when a rotation angle of the second bracket relative to the first bracket is a specified angle,

the first pawl restriction portion extends in the positive direction to the negative direction end of the second pawl restriction portion and is longer than the second pawl restriction portion, and

the first pawl restriction portion restricts movement of the first pawl toward the radially outer side when the second bracket is located toward the negative direction from the specified angle and allows movement of the second pawl toward the radially outer side when the second bracket is located toward the positive direction from the specified angle.