Patent ID: 6336539
Filing Date: 2002-01-08
Classification: F16D

Abstract:
A drain mechanism for a hydraulic power transmission joint adapted to be interposed between an input shaft and an output shaft that are rotatable relative to each other, to transmit torque as a function of the rotational-speed difference between said input and output shafts, said drain mechanism comprising:a drain plug accommodated within a valve block and having a drain hole through which oil is introduced from a high-pressure chamber; a thermo-switch located within a low-pressure chamber in said valve block in such a manner as to be urged by a return spring, said thermo-switch having a head pin that protrudes when a predetermined temperature is reached; a fixed pin fixedly inserted into said valve block, said fixed pin being positioned so as to allow a head pin of said thermo-switch urged by said return spring to abut thereagainst, said fixed pin when said head pin protrudes at said predetermined temperature causing said thermo-switch to retreat against said return spring; and a drain pin slidably located within said drain plug, said drain pin being pressed by said thermo-switch to close said drain hole for the duration in which said predetermined temperature is not reached, said drain pin when said predetermined temperature is reached, opening said drain hole as a result of cutoff of the pressing force caused by a retreat of said thermo-switch.