PURPOSE: To reduce frictional resistance even if reaction force is applied to a brush supporting shaft at the time of use by constituting the brush so that plural pieces of balls for holding the brush supporting shaft roll in the axial direction of the brush supporting shaft.
CONSTITUTION: A brush supporting shaft 7 is held by a device main body through plural pieces of balls 19, 20 being bearings so that it can execute freely a reciprocating motion in the axial direction. Also, the brush supporting shaft 7 is allowed to execute reciprocating driving by a motor-driven device provided in the device main body. Even if pressure being orthogonal to the reciprocating motion direction of the brush supporting shaft 7 by pressure welding to teeth by a brush is generated in the brush supporting shaft 7, this brush supporting shaft 7 is held in a point contact state by the balls 19, 20 as bearings. Moreover, since each ball thereof 19, 20 is subjected to reciprocating rolling so as to follow the reciprocating motion of the brush supporting shaft 7, frictional resistance is reduced remarkably, and in the same way, a load to a driving means of the motor-driven part is reduced. The brush supporting shaft 7 is held by the balls 19, 20 in two front and rear parts in its axial direction, therefore, a reciprocating motion of only a stable axial direction can be obtained.
MIYABAYASHI TADAO
SUZUKI YUJI
UZAWA HIROSHI
| JPH0537135B1 |