Cam phaser having a torsional bias spring to offset retarding force of camshaft friction
US6276321A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 11, 2000 |
| Grant date | Aug 21, 2001 |
| Priority date | — |
| Expiry date | Jan 11, 2020 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T74/2102
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A vane-type camshaft phaser wherein a coil spring under torsional compression or extension is disposed coaxially within an annular cavity formed in either the cover plate or back plate. A first end of the spring is connected to the cover plate or back plate, and a second end extends from the cavity and is connected to the phaser rotor. The spring constant is selected such that a biasing torque is exerted on the rotor in the valve-opening-advancing direction which counters the inherent valve-opening-retarding torque bias of the camshaft during operation. The bias spring permits more rapid response to a demand on the cam phaser for advancing valve timing, and is also useful in orienting the camshaft advantageously, especially an exhaust valve camshaft, in a timing-advanced position when the engine is shut off or operating at low engine speed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.