Power transmission device
US8984874B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 26, 2011 |
| Grant date | Mar 24, 2015 |
| Priority date | — |
| Expiry date | Aug 3, 2033 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16H61/0206
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A power transmission device that transmits power from a motor to a wheel via a hydraulically driven friction engagement element and that includes a mechanical pump driven by the motor to produce a hydraulic pressure that is regulated by a pressure regulating valve; an electric pump that produces a hydraulic pressure; a switching mechanism that either switches an output pressure of the regulating valve or an output pressure of the electric pump to a servo of the engagement element based upon a signal pressure, and a drain valve that opens to drain oil when a hydraulic pressure of a preset pressure or more is applied, and the switching mechanism connects to the drain valve to allow communication between the electric pump and the drain valve in the first state, and shut off communication between the electric pump and the drain valve.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.