| 摘要 |
A tractor transmission includes a hollow PTO input drive shaft having a propulsion input drive shaft located therein, the ends of the shafts terminating adjacent an engine flywheel and carrying PTO and propulsion clutch elements for selectively fixing one or the other or both of the shafts to the flywheel for rotation therewith. The clutch elements are respectively actuated into engagement with a backing plate carried by the flywheel by means of a pair of concentrically arranged fluid-operated pistons. A pilot-operated clutch-lubrication-fluid control valve shifts in response to the operating pressure acting on the pistons to block the flow of fluid to the clutches when both clutches are disengaged, to permit a predetermined amount of fluid to flow to both clutches when both or only the propulsion clutch is engaged and to permit a lesser amount of fluid than said predetermined amount to flow toward the clutches when only the PTO clutch is engaged. A restriction is located in the lubrication fluid passage between the connection of the passage with the PTO and propulsion clutches and the restriction acts to cause substantially all of the lesser amount of fluid to flow to the PTO clutch when only the PTO clutch is engaged. |
