| 摘要 |
<p>An infintely variable belt-drive transmission for an engine has a primary pulley (24) having a hydraulically shiftable disc (24a), a secondary pulley (25) having a hydraulically shiftable disc (28a), a belt (26) engaged with both pulleys, and a hydraulic circuit having a pump (37) for supplying oil. A transmission ratio control valve (44) responds to engine speed for controlling the oil to shift the disc (24a) of the primary pulley (24) in order to change the transmission ratio. A pressure regulator valve (43) responds to the transmission ratio and increases line pressure in the hydraulic circuit with increase of the transmission ratio. For that purpose, a sensor (57) is engaged with the disc (24a) of the primary pulley so as to move therewith, and acts on the spool (54) of the pressure regulator valve (43) to vary the line pressure with variation in position of the disc (24) of the primary pulley.</p> |
