WET CLUTCH

PURPOSE:To improve cooling efficiency by providing a change-over valve interlocked with the gear shift of a shift mechanism in an oil feed circuit and constructing this change-over valve in such a way as to close in the neutral state of the gear stage, thereby stopping oil feeding to a clutch disc. CONSTITUTION:When a first change-over valve 7 interlocked with a first shift lever 8 for forward/backward changeover is in a neutral position N1, oil (e) delivered from an oil pump 5 and cooled by an oil cooler 6 returns to a clutch housing 2 from a valve 7. When a lever 8 is operated to switch the valve 7 to a forward position F or a backward position R, the oil (e) from the pump 5 is fed to a second change-over valve 11 from the valve 7. In this case, if the high/low speed change-over valve 11 is in a neutral position N2, the oil (e) from the pump 5 returns to the housing 2 from a second shift lever 12. On the other hand, if the lever 12 is operated to switch the valve 11 to a low speed position L or a high speed position H, the oil (e) is sprayed onto a clutch disc 1 from a nozzle 14. Accordingly, drag torque is dissolved.