To facilitate machining of a side cover of a vane pump to achieve cost reduction and to restrain leakage of a working oil from a sliding surfaces of a rotor and side cover, in a hydraulic coupling of a power transmission for a four wheel drive vehicle.
The second side cover 43 which divides off rotors 35L, 35R of vane pumps PL, PR of right and left comprises a central center plate 37 and a pair of valve plates 38L, 38R which sandwich the both sides of the plate 37, wherein all hydraulic members such as an oil passage, a check valve, an orifice and the like are disposed intensively in the second side cover 32. By forming a communicating aperture of a communicating groove of the valve plates 38L, 38R in the thickness direction, the valve plates 38L, 38R can be produced by sintering molding leading to cost reduction. By disposing the hydraulic elements not to face toward the external surface of the valve plates 38L, 38R, with which the rotors 35L, 35R come into contact, as far as possible, so as to reduce the leakage of the working oil.
MIYATA KAZUNORI
KUROKAWA TAKUYA
MOCHIZUKI TAKESHI
KONDO YUKITAKA
