Patent ID: 9709162
Date: 2017-07-18
CPC Classifications: F16H,Y10T

Claim:
1. A hydraulic control device of an automatic transmission in which: a forward first shift gear stage is formed by engagement of a first friction engaging element and a second friction engaging element; a second shift gear stage is formed by engagement of the second friction engaging element and a third friction engaging element, the second shift gear stage being at a higher shift gear stage side of the first shift gear stage; and a reverse gear stage is formed by engagement of the first friction engaging element and the third friction engaging element, the hydraulic control device comprising: a hydraulic control valve configured to control an oil pressure supplied to the third friction engaging element; and a switching valve configured to be switched between a first state where a source pressure port of the hydraulic control valve is connected to an oil pressure source and a second state where the pressure is discharged from the source pressure port, wherein: the switching valve becomes the first state when the oil pressure supplied to the second friction engaging element is not less than predetermined oil pressure in a case where the second shift gear stage is shifted to the first shift gear stage since the third friction engaging element is released and the first friction engaging element is engaged in a state where the second friction engaging element is engaged; and the switching valve becomes the second state when the oil pressure supplied to the second friction engaging element is less than the predetermined oil pressure in a case where the second shift gear stage is shifted to the first shift gear stage since the third friction engaging element is released and the first friction engaging element is engaged in a state where the second friction engaging element is engaged.