Patent ID: 8069929

Claim:
An impact tool comprising: a spindle disposed in a housing and configured to be rotated by a motor; an anvil disposed in front of the spindle and rotatably supported by the housing through a metal bearing in a manner coaxial with the spindle, a front end of the anvil having an insertion hole for attaching a bit and protruding from a front side of the housing, and a rear surface of the anvil having a bearing hole in which a front end of the spindle is rotatably supported in a manner coaxial with the anvil; an impact mechanism configured to transmit a rotation of the spindle as a rotary impact force to the anvil; a ring-shaped outer groove formed on an outer periphery of the anvil and opposed to an inner peripheral surface of the metal bearing; and at least one connecting opening radially extending in the anvil and connecting the bearing hole and the outer groove to provide a communication therebetween, wherein the outer groove is formed to have a depth in the range of 3 to 10% of an outer diameter of the anvil, and the connecting opening opens at a rear end of the outer groove in an axial direction of the anvil.