GB586385A - Improvements relating to hydraulic mechanisms - Google Patents

Abstract

586,385. Hydraulically - operated friction clutches ; reversing - gear. WILSON, W. G. March 30, 1945, No. 8124. [Class 80 (ii)] [Also in Group XXIX] In a hydraulic clutch-operating mechanism having relay valve means rotating with and controlling the admission of operating fluid to the clutch, the centrifugal pressure of this fluid acting on one side of the valve is balanced out by that from an independent fluid reservoir connected to the other side. As shown applied to a direct drive and reversing marine gearbox, a multiple clutch 19, Fig. 1, interconnects the input shaft 1 and output shaft 4 for direct drive. The spring-loaded relay valve 18 is in constant communication with the source of supply of operating fluid through passages 27, 28, 26, 25 and 24, and when the pressure is sufficient to force the valve to the right to uncover a port 30 the fluid enters the operating chamber 133 via a passage 32 and moves a piston element 41 to the left to engage the clutch. To compensate for the varying centrifugal pressures of the liquid column acting on the valve head the rear of the valve is in constant communication through a passage 23 with an annular reservoir 21 which is kept supplied with oil by leakage along splines 33, a passage 36 and bearing clearances 36a, and is maintained at a constant head by an overflow passage 22. The clutch is disengaged when the operating fluid pressure falls sufficiently to allow the valve 18 to move to the left cutting off the pressure supply to the chamber 133 and venting it to the low pressure side of the system through passages 32, 30 and 31, when sinuous spring rings 42 situated between the inner set of clutch plates act to separate the plates. The epicyclic reversing-gearing consists of a planet carrier 8, freely journalled on the output shaft 4, connected to the input shaft and carrying pairs of interengaging planets, one planet 9 of each pair meshing with an annulus 11 also journalled on the shaft 4 and the other (not shown) meshing with a sun wheel 10 splined on the shaft 4. Reversed drive is obtained by disengaging the clutch 19 and stopping the annulus 11 which is axially slidable to contact a braking member 16. During direct drive with the clutch 19 engaged and the annulus 11 freed the planet carrier 8 and sun 10 revolve together and the train is locked solid. As shown applied to a cone clutch the input shaft 1, Fig. 2, carries the outer clutch member 47 which encloses the inner member 50, slidably splined to the output shaft 2, in such a way as to define primary and secondary operating chambers 56, 57 connected by clearances 58, 59. To engage the clutch, a valve 80 is moved to a position where it connects the operating fluid supply line 79 to the chamber 56 through passages 81, 76, 75 and 74 and the member 50 is moved to the left bringing the clutch surfaces 49, 51 into initial contact. Full engagement occurs only when the pressure is sufficient to operate on the spring-loaded relay valve 63 via passages 65, 66, moving it to the left to cut off the prior communication of the chamber 57 with the low pressure side of the system through a passage 67, an annular clearance 77 in the valve body and a passage 78, and allowing the pressure to build up therein via the clearances 58, 59. The compensating fluid head is supplied by an annular reservoir 70, acting through passages 69, 68, kept at a constant head by overflow lips 71, and replenished in this case from the operating fluid supply line 79 via passages 82, 83, 73 and 72. Disengagement occurs when the chamber 56 is vented to the low pressure side of the system by moving the valve 80 to exhaust, so allowing the valve 63 to move to the right venting chamber 57. Specification 586,388 is referred to.