Slide structure of seat for vehicle

A slide structure of a seat for a vehicle which positions a cushion seat in the longitudinal direction of the vehicle, comprising:

• a stationary outer rail which extends in the longitudinal direction of the vehicle and includes a substantially C-shaped cross-section an open portion of which is oriented to be inward in the widthwise direction, and is disposed in such a way that its cross-section is elongated in the vertical direction,
• a movable inner rail which extends in the longitudinal direction of the vehicle and fits over the stationary outer rail so as to be slid relative to the stationary outer rail in the longitudinal direction and is fixed on the cushion seat and includes a substantially C-shaped cross-section an open portion of which is oriented to be outward in the widthwise direction, and is disposed in such a way that its side surface is elongated in the vertical direction, whereby the movable inner rail fits with the stationary outer rail in such a way that open portions formed by the respective C-shaped cross-sections are opposed to each other, so that in a case where the cushion seat is located to be in a most frontward position, a front end of the movable inner rail protrudes forward from the front end of the stationary outer rail, while, in a case where the cushion seat is located to be in a most rearward position, a rear end of the movable inner rail protrudes rearward from the rear end of the stationary outer rail,
• said slide structure further comprises a parallelogram link mechanism rotatable about a horizontal axis including a front link and a rear link parallel to each other, one end of each of which is pinned to the cushion seat, while the other end of each of which is pinned to the side surface of the movable inner rail, and
• a means for adjusting the widthwise position which functions to adjust the relative positional relationship in the widthwise direction between the movable inner rail and the front link or the rear link in such a way that a shear load transmitted from the front link or the rear link passes through a shear center situated to be inward in the widthwise direction of the side surface of the movable inner rail.