Patent ID: 8375992
Filing Date: 2013-02-19
Classification: F16K,G05D,Y10T

Abstract:
1. A solenoid operated valve comprising: a hollow cage configured for insertion into a port block having an inlet passage to which hydraulic fluid can be supplied under pressure from a pump, a control passage for supplying pressurized fluid from the inlet passage to a controlled device under the control of the valve, and a return passage for returning fluid to a tank or return line; the cage having axially spaced apart inlet, control and tank ports respectively for connecting to the inlet passage, control passage and tank passage; a spool slidable axially within the cage for controlling a flow of hydraulic fluid from the inlet port to the control port, the spool including a control pressure surface exposed to a control chamber to which pressure may be applied for urging the spool to move within the cage from a position blocking flow from the inlet port to the control port to a position in which the spool allows flow of hydraulic fluid to pass from the inlet port to the control port; a pilot valve supply passage allowing a flow of hydraulic fluid from the inlet port to the control chamber and a discharge passage for flow of hydraulic fluid from the control chamber through a valve seat, the valve seat being fixed in relation to the cage; a pilot valve member movable into and out of engagement with the valve seat for closing and opening a passage through the valve seat to block or permit flow from the control chamber; a solenoid plunger configured to be axially movable under the magnetic influence of a solenoid coil toward the valve seat; a pole piece having a proximal end to which the solenoid plunger is drawn under the magnetic influence of the solenoid coil; a pusher member interposed between the pilot valve member and the solenoid plunger for biasing the valve member against the valve seat when the solenoid plunger is acted upon by the magnetic influence of the solenoid coil at a given energization, the biasing force acting on the valve member determining the maximum pressure that can be obtained in the control chamber without unseating the pilot valve member from the valve seat; a threaded connection between the pole piece and the cage, the threaded connection including a first threaded connecting portion fixed in relation to the pole piece and a second threaded connecting portion fixed in relation to the cage and in threaded engagement with the first threaded portion such that relative rotation of the first and second threaded portions would vary the axial spacing between the proximal end of the pole piece and the valve seat over a range of adjustment; and an anti-rotation device interposed between the first and second threaded connecting portions for locking the first and second threaded connecting portions against relative rotation to fix the axial spacing between the proximal end of the pole piece and the valve seat within such range of adjustment, which axial spacing regulates the maximum pressure that can be supplied to the control port.