Patent ID: 8568273
Filing Date: 2013-10-29
Classification: F16D,F16H,Y10T

Abstract:
1. A hydraulic control device for an automatic transmission, comprising: a linear solenoid valve configured to regulate a line pressure and supply it to an engagement element; a shift valve configured to be supplied with an output oil pressure from the linear solenoid valve; and a controller configured to control the linear solenoid valve and the shift valve; wherein the linear solenoid valve is composed of a sleeve, a spool slidably inserted in the sleeve, a spring for biasing the spool, and a linear solenoid capable of biasing the spool against a biasing force of the spring; the linear solenoid valve is provided with a gain switching chamber which generates a biasing force in a direction to close the linear solenoid valve to switch the gain characteristics of the linear solenoid valve when supplied with an oil pressure; the shift valve is configured to be freely switched between a supply state in which the output oil pressure from the linear solenoid valve is supplied to the gain switching chamber of the linear solenoid valve and a blocked state in which the supply of the output oil pressure is blocked; and the controller is configured to bring the shift valve into the blocked state when a necessary oil pressure of the engagement element is high and into the supply state when the necessary oil pressure of the engagement element is low.