| 摘要 |
A transmission for use in a power train of a motor vehicle comprises a clutch 20 including a cylinder defining a chamber 23, a piston 22, and a clutch disc. A first energy storing means, eg a spring (29, fig 4a), acts upon a side of the clutch disc, against a variable pressure of a fluid in the chamber, and in a direction to expel fluid from the chamber. Means for supplying fluid at variable pressure to the chamber comprises a source of pressurised fluid, and a pressure reducing valve 40 having a housing. A valving element 41 is movable in the housing between a plurality of positions, and second energy storing means, eg a spring 42, is provided for biasing the valving element to a predetermined position in which the pressure of fluid in the chamber of the cylinder counteracts the bias of the first energy storing means. A control valve 50 determines the position of the valving element, and is arranged to assume a plurality of different conditions including a preselected condition in which the control valve exerts no appreciable influence upon the valving element to permit the valving element to assume the predetermined position under the influence of the second energy storing means. |
