To have a gap between an outer race and its flange sealed with grease so as to have any invasion of dust and an increase in torque prevented by providing annular grease sump recess (s) on one side or on both of a facing surface of a flange to an outer race and a facing surface of the outer race to the flange.
A pair of flange 6, 7 close to the width surfaces on both sides of an outer race 3 are provided on the tip end and the middle position of a shaft 1 respectively. On a surface, facing to the width surface of the outer race 3, on the flanges 6, 7, a grease sump recess 8 consisting of an annular groove is formed, and in the recess 8, grease 9 is fitted. By means of such a composition, the grease sump recess 8 is provided on the entire circumference of the outer race of facing surface of the flange 6, 7 and grease 9 is filled therein, a gap between the flanges 6, 7 of the outer race 3 is sealed with the grease 9 so as to prevent invasion of dust powder. In addition, owing to sealing by the grease 9, torque is prevented from its increase so that torque reduction not different from non-contact seal like the effect of labyrinth seal, etc., can be realized.
FUJIOKA NORIO
SATO TAKAYUKI
