| 摘要 |
An infinitely variable belt-drive transmission for an engine comprises a primary pulley (24) having a hydraulically shiftable disc (24a), a secondary pulley (25) having a hydraulically shiftable disc (25a), a belt (26) engaged with both pulleys, and a hydraulic circuit which includes a pump (37) and which supplies oil for controlling the discs of the pulleys (24, 25). A transmission ratio control valve (44) controls the supply of oil to shift the disc of the primary pulley (24a) to change the transmission ratio in response to engine speed, and a pressure regulator valve (43) responds to the transmission ratio to increase the oil line pressure in the hydraulic circuit with increase of the transmission ratio. A throttle position sensor (65) produces a signal in dependence on the opening degree of a throttle valve of the engine. A solenoid operated valve (63) is controlled by that signal to operate the pressure regulator valve (43) so as to increase the line pressure with increase of the opening degree of the throttle valve. |
