GB1233720A - - Google Patents

Abstract

1,233,720. Change speed control. NISSAN JIDOSHA K.K. 17 Dec., 1968 [19 Dec., 1967], No. 59847/68. Heading F2D. A centrifugal regulator-valve for supplying to a vehicle automatic transmission a governor pressure 17 responsive to the speed of its supporting rotating shaft 1, with a stepped parabolic pressure-speed characteristic, comprises primary and secondary centrifugal valves, the former, 6, supplying to the latter, 9, a pilot loading pressure 23, derived from the final governor pressure 17 regulated by the secondary valve 9, the pilot pressure 23 being cut off entirely above a predetermined vehicle speed, whereafter the secondary valve 9 regulates alone, producing a less steep characteristic, Figs. 3 and 4 (not shown). The secondary valve 9 takes in line pressure 15 and regulates it to a governor output passage 17 under the combined influence of outward loading by a spring 11 and centrifugal force; and inward loading by delivery pressure 17 acting on differential lands 34, 35, and pilot pressure 23 acting on the valve-head 33. The primary valve 6 takes in governor pressure 17 and meters it to the pilot passage 23 under the combined influence of inward loading by a spring 8, outward by centrifugal force, and pilot pressure loading 23 on differential lands 27, 28, which can be outward, inward or zero according to the relative sizes of the differential lands. With equal lands, and hence zero pilot loading, the primary valve 6 has no regulating function, but simply cuts off pilot pressure above a predetermined speed. With differential lands the primary valve varies the slope of the governor pressure-speed curve in its regulating range. As is usual, throttle setting influences the shift points. Reference has been directed by the Comptroller to Specification 1,149,986.