Seat reclining apparatus

Abstract

A seat reclining apparatus includes a support frame tiltable about a support axis relative to a first frame, an angle adjustment unit causing a second frame to tiltably move forward or rearward relative to the support frame by a driving force of an actuator, the second frame being displaced in a direction to approach and separate from the support axis, a lock mechanism selectively operated to an unlocked state and a locked state, and a front stopper provided at the first frame to specify a forward tilt limit of the seat back by making contact with a forward tilt contact portion provided at the second frame in a state where the lock mechanism is in the unlocked state, the front stopper including a linearly-shaped contact surface that makes contact with the forward tilt contact portion and that matches or approximates a virtual straight line passing through the support axis.

1 . A seat reclining apparatus comprising:
 a support frame tiltable about a support axis relative to a first frame constituting a seat cushion;   an angle adjustment unit causing a second frame constituting a seat back to tiltably move forward or rearward relative to the support frame by a driving force of an actuator, the second frame being displaced in a direction to approach and separate from the support axis in a case where the second frame tiltably moves forward or rearward relative to the support frame;   a lock mechanism selectively operated to an unlocked state where the support frame is allowed to integrally tiltably move with the angle adjustment unit about the support axis and a locked state where the support frame is prohibited to integrally tiltably move with the angle adjustment unit; and   a front stopper provided at the first frame to specify a forward tilt limit of the seat back by making contact with a forward tilt contact portion provided at the second frame in a state where the lock mechanism is in the unlocked state, the front stopper including a linearly-shaped contact surface that makes contact with the forward tilt contact portion and that matches or approximates a virtual straight line passing through the support axis.   
     
     
         2 . The seat reclining apparatus according to  claim 1 , wherein the first frame is constituted by a plate member and the front stopper serves as a reinforcement member connected to the first frame. 
     
     
         3 . The seat reclining apparatus according to  claim 1 , further comprising a back stopper arranged adjacent to the support frame and specifying a rearward tilt limit of the seat back by making contact with a rearward tilt contact portion provided at the support frame in a state where the lock mechanism is in the unlocked state, the back stopper serving as a connection member connecting the front stopper to the first frame. 
     
     
         4 . The seat reclining apparatus according to  claim 2 , further comprising a back stopper arranged adjacent to the support frame and specifying a rearward tilt limit of the seat back by making contact with a rearward tilt contact portion provided at the support frame in a state where the lock mechanism is in the unlocked state, the back stopper serving as a connection member connecting the front stopper to the first frame. 
     
     
         5 . The seat reclining apparatus according to  claim 1 , wherein the lock mechanism includes a lock arm rotatably supported by the front stopper and being engageable and disengageable relative to the support frame by a rotation of the lock arm. 
     
     
         6 . The seat reclining apparatus according to  claim 2 , wherein the lock mechanism includes a lock arm rotatably supported by the front stopper and being engageable and disengageable relative to the support frame by a rotation of the lock arm. 
     
     
         7 . The seat reclining apparatus according to  claim 3 , wherein the lock mechanism includes a lock arm rotatably supported by the front stopper and being engageable and disengageable relative to the support frame by a rotation of the lock arm. 
     
     
         8 . The seat reclining apparatus according to  claim 4 , wherein the lock mechanism includes a lock arm rotatably supported by the front stopper and being engageable and disengageable relative to the support frame by a rotation of the lock arm. 
     
     
         9 . The seat reclining apparatus according to  claim 1 , wherein the angle adjustment unit includes an internal gear formed at the support frame, an external gear formed at a tilt frame connected to the second frame and having fewer teeth compared to the internal gear, and an eccentric member integrally rotating with a drive shaft which is driven to rotate by the actuator, a portion of the internal gear engaging with a portion of the external gear, the external gear being rotatably mounted at an outer periphery of the eccentric member, and
 the seat reclining apparatus further comprises a power transmission mechanism moving a meshed position between the external gear and the internal gear along an inner periphery of the internal gear by a rotational force of the eccentric member when the actuator is driven, the power transmission mechanism causing the tilt frame to tilt by an angle corresponding to a difference of a number of teeth between the external gear and the internal gear in a case where the external gear rotates one turn along the inner periphery of the internal gear, the tilt frame being displaced in the direction to approach and separate from the support axis when the meshed position between the external gear and the internal gear moves along the inner periphery of the internal gear.   
     
     
         10 . The seat reclining apparatus according to  claim 2 , wherein the angle adjustment unit includes an internal gear formed at the support frame, an external gear formed at a tilt frame connected to the second frame and having fewer teeth compared to the internal gear, and an eccentric member integrally rotating with a drive shaft which is driven to rotate by the actuator, a portion of the internal gear engaging with a portion of the external gear, the external gear being rotatably mounted at an outer periphery of the eccentric member, and
 the seat reclining apparatus further comprises a power transmission mechanism moving a meshed position between the external gear and the internal gear along an inner periphery of the internal gear by a rotational force of the eccentric member when the actuator is driven, the power transmission mechanism causing the tilt frame to tilt by an angle corresponding to a difference of a number of teeth between the external gear and the internal gear in a case where the external gear rotates one turn along the inner periphery of the internal gear, the tilt frame being displaced in the direction to approach and separate from the support axis when the meshed position between the external gear and the internal gear moves along the inner periphery of the internal gear.   
     
     
         11 . The seat reclining apparatus according to  claim 3 , wherein the angle adjustment unit includes an internal gear formed at the support frame, an external gear formed at a tilt frame connected to the second frame and having fewer teeth compared to the internal gear, and an eccentric member integrally rotating with a drive shaft which is driven to rotate by the actuator, a portion of the internal gear engaging with a portion of the external gear, the external gear being rotatably mounted at an outer periphery of the eccentric member, and
 the seat reclining apparatus further comprises a power transmission mechanism moving a meshed position between the external gear and the internal gear along an inner periphery of the internal gear by a rotational force of the eccentric member when the actuator is driven, the power transmission mechanism causing the tilt frame to tilt by an angle corresponding to a difference of a number of teeth between the external gear and the internal gear in a case where the external gear rotates one turn along the inner periphery of the internal gear, the tilt frame being displaced in the direction to approach and separate from the support axis when the meshed position between the external gear and the internal gear moves along the inner periphery of the internal gear.   
     
     
         12 . The seat reclining apparatus according to  claim 4 , wherein the angle adjustment unit includes an internal gear formed at the support frame, an external gear formed at a tilt frame connected to the second frame and having fewer teeth compared to the internal gear, and an eccentric member integrally rotating with a drive shaft which is driven to rotate by the actuator, a portion of the internal gear engaging with a portion of the external gear, the external gear being rotatably mounted at an outer periphery of the eccentric member, and
 the seat reclining apparatus further comprises a power transmission mechanism moving a meshed position between the external gear and the internal gear along an inner periphery of the internal gear by a rotational force of the eccentric member when the actuator is driven, the power transmission mechanism causing the tilt frame to tilt by an angle corresponding to a difference of a number of teeth between the external gear and the internal gear in a case where the external gear rotates one turn along the inner periphery of the internal gear, the tilt frame being displaced in the direction to approach and separate from the support axis when the meshed position between the external gear and the internal gear moves along the inner periphery of the internal gear.   
     
     
         13 . The seat reclining apparatus according to  claim 5 , wherein the angle adjustment unit includes an internal gear formed at the support frame, an external gear formed at a tilt frame connected to the second frame and having fewer teeth compared to the internal gear, and an eccentric member integrally rotating with a drive shaft which is driven to rotate by the actuator, a portion of the internal gear engaging with a portion of the external gear, the external gear being rotatably mounted at an outer periphery of the eccentric member, and
 the seat reclining apparatus further comprises a power transmission mechanism moving a meshed position between the external gear and the internal gear along an inner periphery of the internal gear by a rotational force of the eccentric member when the actuator is driven, the power transmission mechanism causing the tilt frame to tilt by an angle corresponding to a difference of a number of teeth between the external gear and the internal gear in a case where the external gear rotates one turn along the inner periphery of the internal gear, the tilt frame being displaced in the direction to approach and separate from the support axis when the meshed position between the external gear and the internal gear moves along the inner periphery of the internal gear.