Spool drive for pressure regulating, proportional solenoid valve

Claim 1

In a pressure regulating spool valve having a body within which pressurized fluid is admitted to a balanced recess in a spool moved in a dither motion by a proportional solenoid so that a land of said spool spans a regulated port recess in said body and variably opens high and low pressure windows at respective opposite edges of said recess, an improvement comprising: a. circuit means for controlling said solenoid to make said dither motion of said spool follow the relationship X≦Y≦(X+A), wherein X=the distance between opposite edges of said recess, Y=the distance between opposite edges of said land, and A=an axial excursion of said dither motion; b. a socketed plug closing an end of said valve body in a region spaced from said solenoid; c. a pin axially movable within said socket in said plug, said pin engaging said spool and having a diameter substantially smaller than said spool; and d. means for resisting movement force of said solenoid, including a fluid passageway applying regulated pressure fluid to a socket end of said pin and a compression spring engaging said plug and said spool.

Claim 7

A method of operating a pressure regulating valve having a valve body with an internal annular recess having axially spaced edges communicating with a regulated port and a valve spool receiving pressurized fluid in a balanced recess adjacent a land spanning said valve body recess and having opposite land edges communicating respectively with high pressure and low pressure, said method comprising: a. electrically dithering said spool within said body by means of a proportional solenoid driven with a variable force that includes a sinusoidal signal for axially moving said spool in an excursion A; b. dimensioning said land and said recess so that said excursion A is larger than an amount by which an axial distance Y between said land edges exceeds an axial distance X between said valve body recess edges so that X<Y<(X+A); c. arranging said land and said valve body recess so that one pair of said land and recess edges opens a high pressure window for a predetermined portion of a half cycle of said dither and another pair of said land and recess edges opens a low pressure window for a predetermined portion of another half cycle of said dither and at a steady regulated pressure said high and low pressure window openings are substantially equal; and d. applying a portion of the regulated pressure from said regulated port to said valve spool in resistance to said variable force applied via said proportional solenoid.

Claim 8

A method of operating a pressure regulating valve having a valve body with an internal annular recess having axially spaced edges communicating with a regulated port and a valve spool receiving pressurized fluid in a balanced recess adjacent a land spanning said valve body recess and having opposite land edges communicating respectively with high pressure and low pressure, said method comprising: a. electrically dithering said spool within said body by means of a proportional solenoid driven with a variable force that includes a sinusoidal signal for axially moving said spool in an excursion A; b. dimensioning said land and said recess so that said excursion A is larger than an amount by which an axial distance Y between said land edges exceeds an axial distance X between said valve body recess edges so that X<Y<(X+A); c. arranging said land and said valve body recess so that one pair of said land and recess edges opens a high pressure window for a predetermined portion of a half cycle of said dither and another pair of said land and recess edges opens a low pressure window for a predetermined portion of another half cycle of said dither and at a steady regulated pressure said high and low pressure window openings are substantially equal; and d. applying a portion of the regulated pressure from said regulated port to said valve spool in resistance to said variable force applied via said proportional solenoid.