Method and apparatus for shifting ranges in a continuously variable transmission
US6260440A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 17, 1999 |
| Grant date | Jul 17, 2001 |
| Priority date | — |
| Expiry date | Dec 17, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T74/19163
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A transmission assembly having a hydrostatic transmission with a variable displacement hydraulic device which controls a motor speed ratio. The transmission assembly further includes a mechanical transmission coupled to the hydrostatic transmission and having a first range and a second range and an output shaft driven at a travel speed ratio. The torque through the hydrostatic transmission reverses when the mechanical transmission shifts from the first range to the second range. A synchronous travel speed ratio is the motor speed ratio which produces the same travel speed ratio in both the first gear range and the second gear range. An equal displacement travel speed ratio is the travel speed ratio at which a displacement of the variable displacement device in the second gear range is the same as the displacement in the first gear range. A travel speed ratio differential is a difference between the synchronous speed ratio and the equal displacement travel speed ratio. The shift from the first range to the second range is initiated at a travel speed ratio which varies from the equal displacement travel speed ratio by less than eighty percent of the travel speed ratio differential.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.