Patent ID: 8672659

Claim:
A vane air motor comprising: a motor housing comprising a cylindrical wall with a circular cylindrical inner peripheral surface, and first and second end walls that define opposite ends of the cylindrical wall, respectively, such that the circular cylindrical inner peripheral surface and the first and second end walls define a rotor chamber in the motor housing; a rotor provided in the motor housing for rotation around an axis of rotation extending parallel to and spaced from a center axis of the circular cylindrical inner peripheral surface, the rotor having an output shaft portion extending through the second end wall and a support shaft portion extending into the first end wall; first and second radial bearings that are attached to the first end wall and the second end wall, respectively, and rotatably support the support shaft portion and the output shaft portion, respectively; and a casing joined to the motor housing to form a compressed air supply chamber together with the first end wall, the first end wall being formed with an air supply hole through which compressed air is supplied into the rotor chamber; the first end wall comprising: an end wall portion having an inner end surface abutting against an end surface of the cylindrical wall to define the rotor chamber, together with the circular cylindrical inner peripheral surface of the cylindrical wall, and an outer end surface located axially opposite to the inner end surface, the end wall portion further having a circular cylindrical hole which extends through the first end wall in the axial direction of the rotor and receives the support shaft portion of the rotor so as to allow the support shaft portion to rotate in the circular cylindrical hole; and a circular cylindrical wall portion extending opposite to the rotor chamber from the outer end surface into the compressed air supply chamber to define a bearing-housing recess which houses the first radial bearing; the first end wall being formed with a communication groove communicating with the compressed air supply chamber and extending to the outer end surface of the end wall portion, the outer end surface of the end wall portion being formed with a communication recess forming an air passage configured in a loop around the circular cylindrical hole which at least partially faces and thus communicates with a front end of the first radial bearing opposite to a rear end thereof facing the compressed air supply chamber, the communication recess and the communication groove being in communication with each other and constituting an isolated channel to substantially uniformly pressurize the front and rear ends of the first radial bearing in order to prevent leaking of grease from the first radial bearing.