Seat-rotating device

A method for making a seat-rotating device for a seat installed in a vehicle, comprising:

• arranging a plurality of balls on a base member;
• arranging a rotating member on the base member via the plurality of balls;
• attaching a lock member;
• fixing the support member to the base member;
• and
• attaching a rotating member to a seat frame of the seat,
• wherein the support member has a through hole,
• the rotating member has a through hole,
• plurality of balls are disposed between the base member and the rotating member and supporting the rotating member,
• a lock member has an engagement arm portion and is operated between a locked position where the engagement arm portion is engaged with the through hole of the support member and the through hole of the rotating member to prevent rotation of the rotating member and a lock release position where the engagement arm portion is not engaged with the through hole of the support member and the through hole of the rotating member to allow rotation of the rotating member,
• the rotating member has a flat wall portion extending in the radial direction of the rotating member, a side wall portion extending downward from the flat wall portion, and an extending portion extending from the lower end of the side wall portion,
• the extending portion has a facing portion facing a part of the support member and extending in the radial direction, and
• a part of the facing portion is located above the lower end of each of the plurality of balls and below the upper end of each of the plurality of balls.