Vehicle seat sliding apparatus

A vehicle seat sliding apparatus, comprising:

• a first rail fixed to one of a vehicle floor and a seat and having a pair of first vertical wall portions aligned side by side in a width direction, a first connection wall portion connecting base ends of the first vertical wall portions, and a pair of flanges projecting from tip ends of the first vertical wall portions inwardly in the width direction in which the flanges face each other and further bending toward the base ends of the first vertical wall portions;
• and
• a second rail fixed to the other one of the vehicle floor and the seat in a relatively movable manner with respect to the first rail and having a pair of second vertical wall portions aligned side by side in the width direction between the flanges, a second connection wall portion connecting base ends of the second vertical wall portions, a pair of outward extending wall portions projecting outward apart from each other in the width direction from tip ends of the second vertical wall portions while undergoing displacement to one side in a top-bottom direction, and a pair of extending wall portions extending in the top-bottom direction from tip ends of the outward extending wall portions so as to be surrounded by the first vertical wall portions and the flanges, wherein
• a plurality of locking claws are aligned side by side in the direction of the relative movement at tip ends of the flanges of the first rail;
• the second rail is provided with a pair of through-holes penetrating the second vertical wall portions in the width direction and penetrating the outward extending wall portions in the top-bottom direction;
• the vehicle seat sliding apparatus further comprises,
• a locking member connected to the second rail in a rotationally movable manner about an axial line extending in the width direction on an inner side of the second vertical wall portions in the width direction, formed in an insertable manner into the through-holes in the second vertical wall portions, having locking portions capable of locking at least a part of the locking claws in side edge portions in the width direction, and selectively locking the relative movement of the first and second rails as the locking portions fit onto and come off the locking claws in association with a rotational movement in the top-bottom direction, and
• a biasing member biasing and rotating the locking member to a side where the relative movement is locked;
• and
• the outward extending wall portions are provided with a pair of flat portions making a region between outer ends of the outward extending wall portions in the width direction and the through-holes horizontally in the width direction so that an abutment position of the outward extending wall portions and the locking member in association with a rotational movement of the locking member comes closer to the first connection wall portion in the top-bottom direction.