| 摘要 |
1,007,519. Change-speed gear and control. BORG-WARNER CORPORATION. May 21, 1962 [May 25, 1961], No. 19515/62. Heading F2D. Relates to a fluid pressure control system for a vehicle change-speed epicyclic gear generally as described in Specification 973,493, wherein to provide a main line pressure for gear establishing clutch and brake servomotors a main regulator valve 104 is subjected, for pressure increasing, to a control pressure in a line 135 (hereinafter referred to as " TV " pressure) provided by an accelerator pedal position responsive valve 108 and for pressure decreasing, to a further control pressure in a line 138 provided by a valve 109 modulating TV pressure and having a piston 182 subjected to the opposed forces of a pressure variable in accordance with vehicle speed ("governor " pressure) in a line 139 and of TV pressure so that at a certain relationship of Governor and TV pressure it applies full TV pressure through the line 138 for regulation of the valve 104 thereafter directly by TV pressure. In such a system, to extend the range of TV pressure regulation, when the piston 182 is moved leftwards by Governor pressure TV pressure is also directed through ports 193, 194, a restriction 197 and a line 137 to act on a differential area of lands 163, 164 of a piston 152 of the valve 108 to reduce TV pressure in both lines 135, 138 to reduce main line pressure. To partly counteract the effects of increased TV pressure during a " forced " throttle 1-2 upshift, kickdown TV pressure directed through a line 136 (when the accelerator pedal is depressed substantially to its limit) also acts on a differential area of lands 207, 208 of a piston 203 of the 1-2 shift valve 115 to assist Governor pressure so that an upshift occurs at a point different from that of a normal light throttle uplift. During 1-2 kickdown shift kickdown TV pressure in the line 136 acts also on a differential area of lands 206, 208 of the piston 203 to inhibit downshift, however, the differential area of the lands 207, 208 is less than that of the lands 206, 208 and kickdown shift occurs at a point different from that at which a " forced " or light throttle upshift occurs. Specification 1,007,520 also is referred to. |
