Seat slide device

1. A seat slide device comprising:

a lower rail, which is provided on a floor side along a front-and-rear direction;

an upper rail, which is provided on a seat side and movably engaged with the lower rail;

a lock mechanism, which is configured to lock and unlock a movement of the upper rail;

a walk-in mechanism, which makes the seat be movable into a walk-in area located on a front side in the front-and-rear direction by unlocking the lock mechanism due to a forward tilt of a seat back of the seat; and

a movable-range restriction unit which:

allows the seat to move into the walk-in area when the seat is moved toward the walk-in area from a rear side in a state where the walk-in mechanism is operated; and

prevents the seat from moving into the walk-in area when the seat is moved toward the walk-in area from the rear side in a state where the walk-in mechanism is not operated and the lock mechanism is unlocked; and

wherein the movable-range restriction unit comprises;

a position plate, which is provided on the lower rail and defines the walk-in area;

a control cam, which is provided on the upper rail and is rotated due to tilting of the seat back;

an unlock cam, which is provided on the upper rail, is rotated by being pushed by the control cam that rotates due to the forward tilt of the seat back and which unlocks the lock mechanism to operate the walk-in mechanism; and

a stopper cam, which is provided on the upper rail, is rotated along with the rotation of the unlock cam and which includes an engaging portion that is able to engage with the position plate.

2. The seat slide device according to claim 1 ,

wherein the position plate includes:

a plate stopper surface, which intersects a moving direction of the upper rail; and

a plate unlock-maintaining surface, which is provided along the moving direction of the upper rail, and

wherein the engaging portion of the stopper cam includes:

a cam stopper surface, which is abutted against the plate stopper surface of the position plate and prevents the seat from moving into the walk-in area when the seat is moved toward the walk-in area from the rear side in a state where the walk-in mechanism is not operated; and

a cam unlock-maintaining surface, which is slidably abutted against the plate unlock-maintaining surface of the position plate and allows the seat to move into the walk-in area when the seat is moved toward the walk-in area from the rear side in an operating state of the walk-in mechanism, the cam unlock-maintaining surface to maintain the unlocked state of the lock mechanism with the unlock cam.

3. The seat slide device according to claim 1 ,

wherein the control cam, the unlock cam and the stopper cam are rotationally held by individual rotation shafts, respectively.

4. The seat slide device according to claim 1 ,

wherein an interlocking between the unlock cam and the stopper cam are configured by:

a protrusion, which is formed on a position other than the rotation center of one of the unlock cart and the stopper cam; and

a hole, which is formed on a position other than the rotation center of the other of the unlock cam and the stopper cam, the protrusion capable of being loosely fitted into the hole, and

wherein the hole is formed so that a clearance in the moving direction of the upper rail is provided between an inner wall surface of the hole and the protrusion in a state where the lock mechanism is not unlocked by the unlock cam.

5. The seat slide device according to claim 2 ,

wherein a rotation radius from the rotation center of the stopper cam to the cam stopper surface of the engaging portion of the stopper cam is set to be longer than a rotation radius from the rotation center of the unlock cam to the position at which the unlock cam is interlocked with the stopper cam.

6. The seat slide device according to claim 2 ,

wherein the cam stopper surface of the stopper cam is a surface that rotates the stopper cam when abutting against the plate stopper surface of the position plate in a state where the lock mechanism is not unlocked by the unlock cam, thereby generating a force in a direction in which the cam stopper surface more approaches the plate stopper surface of the position plate.

7. The seat slide device according to claim 5 ,

wherein the cam stopper surface of the stopper cam is a surface that rotates the stopper cam when abutting against the plate stopper surface of the position plate in a state where the lock mechanism is not unlocked by the unlock cam, thereby generating a force in a direction in which the cam stopper surface more approaches the plate stopper surface of the position plate.