| 摘要 |
<p>A hydraulically operated continuously variable automotive transmission includes a transmission ratio controlling member (17,Fig.2) and a hydraulic actuator (19) operatively coupled to the transmission ratio controlling member for continuously operating the transmission ratio controlling member to increase or reduce the transmission ratio of the continuously variable automotive transmission. A control valve (35) is provided for applying a controlling hydraulic pressure to the hydraulic actuator (19) dependent on the difference between a first control force commensurate with an indication of the automobile driver's intention of acceleration or deceleration and a second force commensurate with the engine rotational speed, in order to change the direction in which the hydraulic actuator is operated. The control valve (35) comprises a cylinder (41) having two ports (36,37) communicating with the hydraulic actuator, a port (38) communicating with a source (8) of hydraulic pressure, and at least one port (39,40) communicating with an oil tank (12), a first spool (42) slidably disposed in the cylinder (41) and slidably dependent on the difference between the first and second control forces for selectively bringing the ports into and out of communication, a second spool (43) slidably disposed in the first spool and movable in response to a control force commensurate with a control signal, and variable restriction means disposed between the first and second spools for varying the amount of controlling hydraulic pressure applied to the hydraulic actuator.</p> |
