The present disclosure relates to a gap prevention structure of a seat rail for a vehicle. The gap prevention structure includes: a lower rail configured to be fixed to a bottom of a vehicle body and to have a receiving space formed therein; an upper rail configured to have at least a portion thereof received in the receiving space and to slide in a longitudinal direction of the lower rail; a rolling bearing configured to be rotatably coupled to the upper rail and to roll and move in the receiving space in the longitudinal direction of the lower rail; and a gap prevention unit configured to limit rotation of the rolling bearing by pressing the rolling bearing while being inserted between the lower rail and the rolling bearing.

A long slide rail system for a vehicle seat, includes a lower rail extending lengthwise along a vehicle floor panel, the lower rail being fixedly installed on the floor panel, an upper rail coupled to the lower rail and configured for a seat cushion to be slidably moved along the lower rail, a locking module mounted on the upper rail, where the upper rail is slidably movable based on the locking module being unlocked from a locking hole, a fixing guide coupled to the upper rail so as to be spaced apart from the locking module, and a moving guide coupled to the locking module and disposed to face the fixing guide, where the moving guide is selectively connected to the fixing guide based on the locking module being locked on the locking hole so as to control horizontal and vertical clearances with respect to the upper rail.

A vehicle seat comprises: a cushion frame; a backrest frame; at least one main link extending between a first pivot at the cushion frame and a first fixed pivot to be mounted to a vehicle body of a vehicle, wherein the at least one main link is configured to support substantially an entire load on the vehicle seat; and a break link extending between a second pivot at the cushion frame and a second fixed pivot to be mounted to the vehicle body, the break link comprising first and second members joined to each other at a third pivot, wherein one of the first or second members has a pin that extends into an elongate slot on another of the first or second members.