Patent ID: 9545821
Date: 2017-01-17
CPC Classifications: B60B,B60K,B60T,F16D,F16H

Claim:
1. A power transmission device comprising: a spindle case defining a central hole through which an axle shaft penetrates in a central portion, and a brake chamber in a region around the axle shaft at a base end portion; a wheel hub rotatably supported by an outer circumference of the spindle case and defining a final chamber, wherein the final chamber and the brake chamber are configured to allow oil to flow therebetween via communication with the central hole of the spindle case; a wet type brake mechanism contained in the brake chamber and configured to apply braking on rotation of the axle shaft with respect to the spindle case; and a deceleration mechanism contained in the final chamber and configured to decelerate and transmit rotation of the axle shaft to the wheel hub, wherein through holes that allow additional fluid communication of the brake chamber and the final chamber of the wheel hub are provided in a flange wall portion of the spindle case, the through holes being openings provided at a plurality of positions, including in the flange wall portion and on an outer circumferential side of a midpoint of a radius of the brake chamber, and wherein the oil in the brake chamber is supplied inside the final chamber through the through holes when the axle shaft rotates.