| 摘要 |
PURPOSE:To make smooth the transition from the direct coupling range of a direct coupling clutch from the high load side indirect coupling range, by providing a change-over operation prolonging means for gradually reducing the coupling force of the direct coupling clutch, in a change-over mechanism for changing over the direct coupling clutch into its operating condition. CONSTITUTION:When such a change occures that the travelling condition is shifted from the direct coupling range to a high load indirect coupling range upon speed shift operation of a vehicle or the like, a release pressure is fed into a releasing oil chamber 7b to shift a direct coupling clutch 7 from the direct coupling condition to the indirect coupling condition. In this stage, a spool in a hydraulic control valve 16 is driven to be gradually moved leftward by a control unit 13 and a duty solenoid valve 14 which constitures a means S' for prolonging the change-over operation of a spool in a hydraulic control valve 16. Accordingly, the coupling force of the direct coupling clutch is gradually decreased. |
