| 摘要 |
Hydraulic controls in a transmission for engaging a clutch for the F-R, or forward or reverse, direction before a clutch for first, second, or third speed. Flow of hydraulic fluid to each direction clutch and to each speed clutch is by way of a reducing valve which modulates fluid pressure in controlled way by throttling the flow. After the power unit for the clutch for the F-R clutches and the power unit for the clutch for first, second or third speed are filled with fluid by the reducing valve, pressure in the power units is then slowly raised by the valve linearly toward its maximum; for this purpose the hydraulic controls are supplied by a single source of hydraulic fluid and operate therefrom to provide a pair of modulated pressure outputs which are maintained with varying differences throughout their range of operation, and which operate the selected one of the F-R clutches and the selected one of the first second or third clutches. The F-R clutches are the ones which receive the higher modulated pressure output and which are constructed, proportioned in size, and arranged to have a higher speed capability and smaller energy absorbing capacity in their design, and they operate so as to be fully hydraulically engaged at the higher pressure output, and hence slightly before, the speed clutches.
|
