Power-branched continuously variable transmission
View Patent ↗A power-branched continuously variable transmission having an input shaft and an output shaft, and a power divider transmission that divides the torque of the input shaft between two torque transmission paths. One path is connected to the output shaft. A variable speed drive unit connects the transmission paths with each other, and a start-up converter is located in one of the torque transmission paths between the power divider transmission and the variable speed drive unit.
1. A power-branched continuously variable transmission, said transmission comprising:
an input shaft and a unitary output shaft, wherein the unitary output shaft is connected with a differential axle to drive motor vehicle wheels;
a power divider transmission for dividing an input shaft torque between two torque transmission paths, only one of which paths is connected to the output shaft;
a variable speed drive unit positioned between and interconnecting the two torque transmission paths with each other, wherein the variable speed drive unit is a frictionally-engaged, continuously-variable transmission selected from the group consisting of a belt-driven conical-pulley transmission, a toroidal variable speed drive unit, and a cone-ring transmission; and
a start-up converter positioned in one of the torque transmission paths between the power divider transmission and the variable speed drive unit.
2. A transmission in accordance with claim 1 , wherein the start-up converter is a hydrodynamic converter.
3. A transmission in accordance with claim 1 , wherein the start-up converter is an electrical machine that is operable both as a generator and as a motor.
4. A transmission in accordance with claim 2 , wherein the start-up converter includes a lockup clutch.
5. A transmission in accordance with claim 1 , wherein the torque transmission path that includes the start-up converter is connected to the output shaft.
6. A transmission in accordance with claim 1 , wherein the torque transmission path that includes the start-up converter is connected to the output shaft through a transmission ratio stage.
7. A transmission in accordance with claim 1 , wherein a transmission ratio stage is included between the power divider transmission and the variable speed drive unit in the torque transmission path that does not include the start-up converter.
8. A transmission in accordance with claim 1 , wherein the power divider transmission is a planetary transmission.
9. A transmission in accordance with claim 1 , wherein at least one torque transmission path is connected directly to the output shaft.
10. A transmission in accordance with claim 3 , wherein the start-up converter includes a lockup clutch.