GB496466A - Improvements in feed devices for clutches for hydraulically operated change speed gears - Google Patents

Abstract

496,466. Variable - speed gearing. KEGRESSE, A. May 16, 1938, No. 14593. Convention date, April 16. [Class 80 (ii)] A centrifugally-actuated control valve for a group of hydraulically operated clutches of a change-speed gear of the kind described in Specifications 466,543, 482,632, and 489,317, comprises a double-acting valve member 5, 6 radially arranged on the rotating clutch housing 2, the inner end of which controls the supply of pressure fluid through passages 49, 50 from a pump 44 and the outer end the exhaust of the pressure fluid through an outlet 71. At a certain minimum engine speed the valve 5, 6 moves out under the action of centrifugal force against a spring 11 to pass the pressure fluid to a chamber 53 behind the diaphragm 16 of the first speed clutch 17, 18 and to close the exhaust outlet 71. The first-speed clutch is thereby engaged. The passage of the pressure fluid from the pressure chamber of the firstspeed clutch is controlled by valves 12 of different spring-loadings for the second and third speed clutches 17, 23 and 33, 32 respectively, which valves operate as the engine speed and pressure of the fluid rises to bring in second and third speeds successively. The driven gears 36, 26 and 21 are in free-wheel connection with the driven shaft 22 so that on the higher speeds the lower speed gears over-run. As the engine speed falls the third and second speed clutches are successively released by the fall in pressure of the fluid, the valves 12 opening to exhaust, and finally the valve 5, 6 is moved inwardly to open the exhaust outlet 71 to release the first-speed clutch. If the vehicle is stopped suddenly by application of the brakes the valve 5, 6 may open to exhaust first to release all the clutches simultaneously.