| 摘要 |
PROBLEM TO BE SOLVED: To provide a rolling bearing for a power tool motor realizing a dust proof property of a bearing, low torque, long life time and compatibility with resin under rotation from a low speed to a high speed. SOLUTION: In this rolling bearing for power tool motor, a plurality of rolling elements arranged between raceway surfaces of an inner ring and an outer ring are rotationally retained at substantially equal intervals by a retainer, and a grease containing of synthetic hydrocarbon oil with a kinematics viscosity of 20 to 150 mm2/s at 40 deg.C, bended with urea compound, is sealed by a seal plate fitted into a seal groove in the outer ring. The seal plate is made of an elastic body reinforced by a metal plate, and provided at the smallest diameter side thereof with a lip which is usually in contact with a plane portion of a seal groove of the inner ring, and with a collar portion having an outer peripheral surface with a circular arc section, and a passage for discharging outside a gas within the bearing. The seal groove of the inner ring is provided with a plane portion coming into contact with the lip, and round surface portion with a circular arc section, corresponding to the collar section. Usually, a little clearance is ensured between the collar portion of the seal plate and the round surface portion of the seal groove of the inner ring.
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