| 摘要 |
<p>A hydraulically engaged clutch comprises an actuating chamber wherein pressurized hydraulic fluid acts on a piston (40) to engage the clutch and a clutch chamber (26) for clutch cooling fluid which cools the stack of discs (32, 34). A spool valve (64) in a radial passage (60) in the clutch housing controls flow of cooling fluid to the clutch chamber (26) and is acted upon by the pressure in the actuating chamber to keep the valve open while clutch-engaging pressure is supplied from a pump (42). The spool (64) is also acted on by centrifugal force to close the valve when pressure in the actuating chamber falls sufficiently. The clutch chamber then drains through a passage (66) in order to avoid viscous drag. Preferably the valve (64) moves to the open position, as pressure rises in the actuating chamber before the piston (40) engages the clutch, in order to ensure cooling during engagement.</p> |
