Finishing machines for internal spline tooth surfaces

A finishing machine for internal spline tooth surfaces comprising;

• a holding device for holding a work having internal spline tooth surfaces;
• a grinding stone having a plurality of tooth portions for simultaneously grinding the internal spline tooth surfaces of said work, the grinding stone having an axial length and an outer diameter, the axial length being greater than the outer diameter of said grinding stone;
• a rotating device operatively associated with the grinding stone for rotating the grinding stone in a forward rotating direction and a reverse rotating direction;
• a rotation direction control device for controlling the rotating direction of the grinding stone to change rotation of the grinding stone between the forward rotating direction and the reverse rotating direction;
• and
• a vibrating device for vibrating said grinding stone up and down with a long stroke in an axial direction of said work to grind an entire axial length the internal spline tooth surfaces of the work in each up and down stroke of the grinding stone.