Seat slide device

An assembling method of a seat slide device, comprising:

• providing a lower rail having a channel structure;
• providing an upper rail having a channel structure, the upper rail being slidably engaged with the lower rail in a manner to define an elongate enclosed space therebetween;
• and
• providing a lock mechanism including a lock arm disposed on the upper rail to be pivotable around a pivotal center axis which is approximately in parallel to an elongate direction of the upper rail, at least two lock pawls formed on the lock arm along the elongate direction of the upper rail, a plurality of lock holes formed on the lower rail and the upper rail, the lock pawls being inserted through the lock holes to lock the upper rail with respect to the lower rail, a pair of slits formed at predetermined front-and-rear positions of a side surface of the upper rail, and a bearing bracket configured to pivotably support the lock arm, the bearing bracket and the lock arm being disposed within the enclosed space between the upper rail and the lower rail and including a pair of bearing portions configured to pivotably support both ends of the lock arm via a pair of pivotal axles of the pair of bearing portions, both ends of the lock arm and the pair of bearing portions being disposed within inner spaces defined by the pair of slits.