Yutaka Giken Co., Ltd.

Yoshihisa Yamamoto

Tokuji Yoshimoto

Seiji Makita

Akira Kitajima

In a fluid transmission device, a male fitting surface of a periphery of a diameter-expanded portion of a pump shell is fitted to a female fitting surface of an inner circumference of a peripheral wall portion of a cylindrical transmission cover, and a fillet weld being is formed between an end surface of the peripheral wall portion and a peripheral surface of the diameter-expanded portion along an entire circumference, thereby connecting together the pump shell and the transmission cover. An annular recess is formed in an inner circumferential surface of the peripheral wall portion to adjoin the female fitting surface on the side opposite from the fillet weld. A portion of the transmission cover corresponding to the recess constitutes an annular thin-walled portion which has a thickness smaller than the portions of the transmission cover along the opposite sides of the annular thin wall portion. Therefore, even if the diameters of the pump shell and the transmission cover are increased, the durability of the pump shell and the transmission cover can be improved by alleviating excessive stress concentration on the fillet weld between the pump shell and the transmission cover.

Fluid transmission device

In a transmitting system for a small-sized vehicle, a centrifugal clutch, and a torque converter including a pump impeller connected to an output drum of the centrifugal clutch and a turbine impeller connected to an output gear, are placed between a crankshaft of an engine and the output gear. The pump impeller and the output drum adjacent to the pump impeller are integrally coupled, with an open surface of the output drum facing to an opposite side to the pump impeller, to be constructed as a single component. Thus, occurrence of rotation vibrations and unusual noises can be prevented without requiring machining with high precision, and the numbers of components and assembling steps can be reduced while providing favorable maintainability.

Growing community of inventors

Shizuoka, Japan

Yoshihisa Yamamoto