Patent ID: 8821332
Filing Date: 2014-09-02
Classification: F16H,Y10T

Abstract:
1. A power transmission device, comprising: a shift device that is capable of transmitting power applied to an input shaft to an output shaft by shifting a speed ratio to a plurality of shift speeds by engagement and disengagement of a plurality of hydraulic friction engagement elements; a differential mechanism that is coupled to right and left driving wheels; a countershaft that transmits the power from the output shaft to the differential mechanism; and a case that accommodates the shift device, the differential mechanism, and the countershaft, wherein a breather chamber having an opening at least on its one end side and extending coaxially with the countershaft is formed in the countershaft, one end of a vent pipe that is placed so as to extend through the case and that has an opening at its both ends is inserted in the opening of the breather chamber, and a plug, which closes a gap between an inner peripheral surface of the breather chamber and an outer peripheral surface of the vent pipe so as to allow air to flow between inside of the case and the breather chamber and so as to restrict entrance of oil into the breather chamber, is placed in the opening of the breather chamber.