| 摘要 |
PURPOSE:To improve cooling effect of operation oil by means of an oil cooler in a low speed stage of an automatic transmission. CONSTITUTION:An oil passage 112 through which oil is discharged for adjusting a pressure from a pressure regulator valve 40 is connected to line pressure oil passage 100 of an oil pump 34 through a first orifice 150. A flow rate switching valve 124 and a second orifice 152 are parallelly arranged upstream of an oil cooler 36. The flow rate switching valve 124 can be selectively switched to an interruption position with which the valve is closed and the oil is supplied to the oil cooler 36 only through the second orifice 152, and a communication position with which the oil is supplied while bypassing the second orifice 152. The flow rate valve 124 is switched based on the speed pressure of an automatic transmission. It is switched to the communication position under the first, second and third speed, while switched to the interruption position under the fourth speed. |
