Patent ID: 8186689

Claim:
A power tool for use with grease, comprising: an electric motor; a gear chamber accommodating therein a reduction gear train and containing therein the grease for lubricating the reduction gear train, the reduction gear train reducing rotation of the electric motor, the rotation of the electric motor being transmitted to the reduction gear train via a rotary shaft; and a sealing device for preventing the grease from leaking out of the gear chamber, the sealing device including: a separating wall separating the gear chamber from the electric motor and supporting the rotary shaft via a bearing; a sealing member attached to the rotary shaft so as to be able to rotate together with the rotary shaft; and a grease return part provided on the sealing member on the side of the gear chamber; wherein the grease can be blown off in a direction away from the bearing as a result of the centrifugal force produced by the rotation of the rotary shaft.