GB1238386A - - Google Patents

Abstract

1,238,386. Change-speed control; valves. GENERAL MOTORS CORP. 20 Nov., 1969 [11 Dec., 1968], No. 56783/69. Headings F2D and F2V. A two-stage fluid pressure governor for providing a pressure signal dependent on the speed of rotation of an output shaft 70, and suitable for controlling 1-2 and 2-3 ratio changes in an automatic multiple-speed power transmission for a motor-vehicle comprises U-shaped primary and secondary centrifugal weight members 44, 38 pivoted on pins 36, 34 on a governor shaft 12 which, via the pins 36, 34, is rotationally fast with a surrounding nylon gear 66 which meshes with a conventional speedometer drive gear 68 fast on the output shaft 70, the centrifugal weights 44, 38 each having a tab 52, 50 arranged on opposite sides of the shaft 12 relative the respective weights and controlling pressure relief (i.e. exhaust) ball valves 60, 58 which regulate line pressure supplied via restrictors 28 and 29 to centre chambers 20, 21 respectively of the governor shaft 12, the respective regulated primary and secondary governor pressures being conducted via ports 30 and 31 to the 1-2 and 2-3 shift valves (not shown). The primary and secondary governor pressures, relative to corresponding road speeds, for the 1-2 and 2-3 shift valves resp., follow the curves OA and OC in graph of Fig. 4. In Fig. 5, the primary and secondary centrifugal weight members 72, 74 are mounted on a common pivot pin 34 and have a spring loaded interconnecting pin 86, 90 whereby a single pressure relief ball valve 80 is jointly controlled by the centrifugal weights 72, 74 such that a continuous progressive two-. stage effect is achieved as illustrated in curve OAB in Fig. 4, the primary weight 72 ceasing to be effective above point A on the curve. In Fig. 6, the primary and secondary centrifugal weight members 114 and 116 are again, as in Fig. 1, separately mounted on pivot pins 34, 36 and separately control pressure relief ball valves 102, 104 to regulate governor pressure in a common through bore 100 in the governor shaft 112, the secondary weight 116 being spring loaded at 126 whereby it remains initially inoperative during operation of the primary weight 114 regulating governor pressure along the curve OA, the primary weight 114 holding the valve 102 closed at and above the road speed represented by point A whilst the pressure in the through passage 100 at and above the pt. A is sufficient to overcome the combined centrifugal and spring load on the secondary weight 116 whereby progressively increasing governor pressure as represented by the curve AB in Fig. 4, the overall effect being again as in Fig. 5 whereby the primary and secondary weight controlled valves provide a continuous progressive two-stage effect as illustrated in curve OAB of Fig. 4.