Patent ID: 6257274
Filing Date: 2001-07-10
Classification: B60T,F16D,Y10T

Abstract:
A valve opening and closing mechanism comprising:a cylinder including an inlet for supplying fluid;a control piston slidably fitted to said cylinder, said control piston including a first fluid passageway for supplying fluid to said cylinder;a valve guide supported in a fluid chamber defined by said cylinder and said control piston, said valve guide including a shaft portion inserted into the first fluid passageway of said control piston and defining a first clearance for supplying fluid, and a valve support portion formed into a collar at a base end of the shaft portion of said valve guide and facing an end surface of said control piston, the shaft portion of said valve guide having a conical surface portion for reducing a first sectional area when said control piston is displaced toward said fluid chamber; anda valve assembly loosely fitted to the shaft portion of said valve guide so as to move toward said control piston with flow of fluid to narrow the first fluid passageway of said control piston when a flow rate of the fluid flowing through the first fluid passageway of said control piston is greater than or equal to a predetermined value.