Patent ID: 8678341
Filing Date: 2014-03-25
Classification: B60T,F16K

Abstract:
1. A normally closed solenoid valve comprising: a valve housing defining a valve chamber and having a seating surface; a valve body configured to be moved into and out of contact with the seating surface, thereby closing and opening the valve; a movable element at least partially made of a magnetic material and mounted in the valve chamber of the valve housing so as to support the valve body; a spring biasing the movable element in a valve closing direction; a solenoid for applying a magnetic attraction force to a movable element attracting portion of the valve housing, thereby moving the movable element in a valve opening direction; the movable element including a trunk possessing an outer diameter larger than any other portion of the movable element; one of the valve housing and the movable element being formed with a cylinder having a diameter smaller than the outer diameter of the trunk of the movable element and having an open end, and the other of the valve housing and the movable element being provided with a piston configured to be moved relative to the cylinder when the movable element moves; wherein the piston is inserted in the cylinder through the open end of the cylinder, thereby defining a damper chamber between the piston and the cylinder of which the volume is variable when the piston and the cylinder move relative to each other; wherein a restricted passage is defined between the damper chamber and the valve chamber through which hydraulic fluid is introduced into the damper chamber from the valve chamber or discharged from the damper chamber into the valve chamber; and wherein the restricted passage comprises a gap between a radially outer surface of the piston and a radially inner surface of the cylinder, and wherein said gap has a radial dimension smaller than a radial dimension of a gap defined between a maximum outer diameter portion of a radially outer surface of the trunk of the movable element and a radially inner surface of the valve chamber.