Patent ID: 7513269
Filing Date: 2009-04-07
Classification: F16H,F16K,Y10T

Abstract:
1. A hydraulic control system for an automatic transmission, comprising: a detection circuit serving as a part of a hydraulic circuit to detect a hydraulic pressure; an accumulator including a casing, a valve element slidably disposed in the casing, and a spring for biasing the valve element, the valve element dividing the inside of the casing into a first space that communicates with the detection circuit and a second space that houses the spring and communicates with an exhaust circuit; a pressure switch for detecting the hydraulic pressure; and a pressure switch circuit connected to the pressure switch, and connected to a slide section of the casing so as to communicate with the first space at one end and with the second space at the other end, wherein the valve element opens communication between the pressure switch circuit and the exhaust circuit when a hydraulic pressure applied to the detection circuit is lower than a predetermined hydraulic pressure, closes communication of the pressure switch circuit with the detection circuit and the exhaust circuit when the hydraulic pressure applied to the detection circuit is equal to the predetermined hydraulic pressure, and opens communication between the pressure switch circuit and the detection circuit when the hydraulic pressure applied to the detection circuit is higher than the predetermined hydraulic pressure.