| 摘要 |
PURPOSE:To prevent drag from being caused when fastening and releasing operations are carried out by setting so that air is not left in an operating liquid pressure chamber of a rotary clutch to govern speed change control of an automatic transmission. CONSTITUTION:When liquid pressure is supplied to a chamber 18, a piston 17 is stroked, and push-presses a clutch pack 16, and a clutch is put in a fastening condition. When the liquid pressure of the chamber 18 is reduced, the piston 17 is returned by a return spring 21, and the clutch is put in a release condition. When air exists in the chamber 18 in a clutch release condition, liquid in the chmaber 18 gathers to the outer peripheral part since specifice gravity is large, and air of small specific gravity gathers to the inner peripheral part. Here, a microscopic clearance 29 arranged in the inner peripheral part lets the air in the inner peripheral part escape to a drain strip groove 26. Thereby, since the air becomes nonexistent, and entering/missing of pressure to/from the chamber 18 can be carried out speedily, so that drag of the clutch can be eliminated. |
