| 摘要 |
PCT No. PCT/FR91/00159 Sec. 371 Date Oct. 24, 1991 Sec. 102(e) Date Oct. 24, 1991 PCT Filed Feb. 27, 1991 PCT Pub. No. WO91/13275 PCT Pub. Date Sep. 5, 1991.A transmission (1) has an input (2) connected to an engine (3). At a speed above idling, a centrifugal clutch (9) connects the engine to a pump (8) of a torque converter (7) and also to a sun gear (14) of a planetary gear train (13). A turbine (11) of the torque converter is connected to a ring gear (16) of the planetary gear train, and a planet carrier (18) is connected to an output (4) of the transmission. A free wheel (22) mounted between the ring gear and a stationary housing prevents reverse rotation of the ring gear. At low engine speeds, the power passes via the sun and planet gears through the planet carrier to the output, while reaction torque exerted by the planet gears on the ring gear is greater than forward torque transmitted through the torque converter, so that the ring gear is held stationary by the free wheel. In this condition, the planetary gear train acts as a mechanical speed reducer. As the engine speed increases, the torque transmitted by the converter to the ring gear exceeds the reaction torque of the planet gears, driving the ring gear in the forward direction at progressively increasing speeds that approach the speed of the planet carrier, thus progressively decreasing the speed reduction of the gear train. The planetary gear train serves to add the engine power received directly at the sun gear and via the hydraulic torque converter at the ring gear. |
