IMPROVEMENTS IN HYDRAULIC VALVES

摘要

1,214,821. Valves; friction clutches. PERKINS ENGINES Ltd. 14 Feb., 1968 [17 Feb., 1967], No. 7579/67. Headings F2C and F2V. A valve which may be used to control the operation of a lock-up clutch in a hydrokinetic torque converter includes a valve member 7 movable in a valve chamber 6 between first and second positions to regulate the flow of hydraulic actuating fluid to the clutch, and a spring 11 arranged to urge the valve member towards the first position and to apply a decreasing force to the valve member as it moves towards the second position. In the preferred embodiment, the valve is actuated by centrifugal force and moves outwardly to engage the clutch at a higher rotational speed, than that at which the spring is able to return it to its inner position. The speeds at which outward and inward movements occur may be 1800 and 1200 r.p.m. respectively. A pin 10 carried by the valve member is clipped within a looped end 12 of the spring 11 which has its free ends notched for engagement with a pair of knife-edged struts 14. A spring clip 17 and an interchangeable domed washer 18 limit the travel of the valve member which may be used to admit fluid under pressure alternately to opposite sides of a clutch plate or to one side of the plate only when the latter is spring-loaded to either the engaged or disengaged position. Disengagement of the clutch plate may also be effected by blocking flow through one part of the valve to create a centrifugal head. The outer ends of the struts 14 may engage cantilevered leaf springs while the inner ends engage the lower end of a short shaft having a ball-jointed connection with the valve member. The lower end of the shaft may alternatively be engaged by the inner ends of inclined coil or U-springs the outer ends of which are located in shoulders on the valve body.