| 摘要 |
1,023,060. Variable-speed gear. FORD MOTOR CO. Ltd. Dec. 21, 1964 [Dec. 30, 1963], No. 51767/64. Heading F2D. A steplessly-variable-ratio friction gear for a motor-vehicle comprises balls 36 mounted with radial freedom in a permanently fixed carrier 38 and frictionally engaging an outer driving 22, and an inner driven, 48, race-assembly, each comprising a pair of concave elements 26, 28 and 30, 32, splined in their respective housing and urged axially towards each other to clamp the balls therebetween by fluid pressure 164, 152 acting on annular pistons formed by the raceelements 26, 32. The speed-ratio, varying through under- and over-drives, is varied by varying the axial separation of the inner race elements 30, 32 by varying the pressure 152 under the automatic control of a shift-valve 114, subject to opposing engine-speed-responsive and engine accelerator-pedal-responsive pressures 64, 110, the clamping pressure 164 acting on the outer race elements 26, 28 being varied inversely in relation to the shift pressure 152 to permit the outer race elements to open or close as required by the radial movement of the balls 36 in response to axial movement of the inner race element 32. For traction the axial pressure 164 on the outer race elements is also varied in accordance with engine-manifold depression 204 and with engine speed. The variable drive through the balls reverses the direction of input rotation to drive the vehicle forwards. For reverse the input race 22 is disconnected from the input shaft 10 by releasing a fluid-pressure engaged clutch 16, and the input and output shafts 10, 48 are directly connected together by a fluid-pressure-engaged cone clutch 52. The output of the gear is connected to an hydrodynamic torque-converter. Fluid pressure supply and regulation.-A single engine-driven pump 58 supplies a pressure main 66 under control of a pressureregulator valve 68 which regulates to exhaust 80 and to pump-displacement increasing and decreasing lines 72, 74, and is loaded by a spring 70 and by fluid pressure 216 supplied through a shuttle valve 212 which loads the regulator valve 68 with either shift-control (inner race) pressure 152 or traction (outer race) pressure 164, whichever is the higher, to increase regulated line pressure 66 in accordance with gear loading. Shift control pressures.-An engine driven governor valve 62 (not described) provides an engine-speed-responsive governor pressure 64. A TV valve 94, loaded at 106 by the engine accelerator pedal, provides throttle-variable (TV) pressure 110. Ratio-shift valve 114 is urged right by a spring 120 and TV pressure 110, and left by governor pressure 64 and a spring 128 with screw-adjustable pre-load. The valve 114 controls the supply of line pressure 66, 116 to the shift-pressure line 152 through an idle valve 148 in which, at engine idle speeds, a spring 146 is able to overcome governor pressure 64, 132 to move the idle valve 148 to the right (position shown), where it by-passes the automatic shiftvalve 114 and supplies full line pressure 66, 116 directly to the shift-pressure line 152, to cause minimum separation of the inner race elements 30, 32 and, through radial movement of the balls 36, maximum separation of the outer race elements 26, 28, enforcing maximum reduction ratio. During normal running increase in governor pressure 64 and/or decrease in TV pressure 110 shifts the automatic shift-valve 114 left to reduce shift-pressure 152, permitting the inner race elements to approach maximum separation for upshift, such movement being accompanied by closing movement of the outer race elements 26, 28 caused by a corresponding increase in clamping pressure 164 acting thereon. Clamping pressure 164 on the outer race elements 26, 28 is varied inversely as the shift pressure 152 to allow the necessary approach and separation of the outer race elements as complementary to that of the inner race elements. In addition, for traction, the clamping pressure 164 is increased with increase in engine torque as manifested by reduction in manifold depression, and is also increased with increase in engine speed. For this purpose clamping pressure 164 is regulated by two regulator valves 162 and 176, the former loaded by shiftpressure 152, 160, the latter by governor pressure 64 and a pressure 182 which is regulated inversely by engine-manifold depression 204 in a regulator valve 184, being zero at maximum depression. Automatic declutching.-At engine idle governor pressure 64, 180 may be arranged to be insufficient to move the regulator valve 176 rightwards to cover the exhaust port 178, so that clamping pressure 164 is zero and the balls slip. This provides automatic engine release at idle speed for forward starting and stopping the vehicle. A manual valve 85 has the following settings. Drive, DR, shown, pressurizes a line 88 engaging the input-race clutch 16. Hill-brake, HB, additionally pressurizes a line 86 to act rightwards through a piston 136 on the automatic shift-valve 114 to enforce maximum reduction ratio. Neutral, N, exhausts the lines 86, 88, releasing the input-race clutch 16, and pressurizes a line 92 enforcing rightward setting (shown) of the idle valve 148 to enforce maximum reduction ratio independently of the automatic shift valve 114. Reverse, R, pressurizes also the engaging line 90 of the reverse clutch 52. |
