| 摘要 |
<p>PURPOSE:To always apply a constant predetermined pressure to a release bearing by relieving the air in a clutch operating chamber through a relief valve to the atmosphere under a clutch engaged condition where an operating chamber of a pneumatic actuator is shut off from an air tank by a selector valve. CONSTITUTION:When an electromagnetic selector valve C is operated to cut the supply of pressure air from an air tank 2 to a pneumatic actuator 5, a rod 12 and pistons 11 and 15 are moved leftwardly by a return spring of a clutch, and the air in an operating chamber 31 is fed through an operating chamber 22 of a control valve, a passage 34a, an atmospheric air chamber 21 and a relief valve 18 to a breather 36, and is relieved to the atmosphere with a relief pressure maintained. Simultaneously, the oil in an oil pressure chamber 7 is fed to a hydraulic cylinder 29 to move a piston 20 rightwardly and close the passage 34a, thereby suppressing the rightward movement of the piston 15. At this time, an electromagnetic closing valve A or B is duty- controlled to limit an oil flow to be returned from the oil pressure chamber 7 to the atmospheric pressure chamber 40, thereby ensuring smooth engagement of the clutch. Thus, a predetermined preload may be applied to a release bearing.</p> |
