HYDRAULIC VALVE HAVING PRESSURE COMPENSATED FLOW CONTROL

摘要

A hydraulic valve having a hollow valve body configured with a supply port and a supply port. The hollow valve body has several different internal diameters. An elongate spool is reciprocally received in the body and has a large diameter annular spool ring oriented adjacent a sensing land inside the hollow body forming a gap with a sensing land to cause a pressure drop across the gap in response to a flow of fluid from the pressure port through the gap to the control port. A servomotor reciprocally drives the spool lengthwise of the valve body against a spring force. When flow of fluid occurs in response to servomotor movement of the spool, the pressure drop across the gap combined with the spring force determines a pressure balanced location to which the spool is moved.

主权项

1. A hydraulic pressure compensated flow control valve, comprising:
a valve cartridge body having at least a supply port configured to be connected in fluid circuit with a pressurized fluid source and a control port configured to be connected in fluid circuit with a load, said valve body having a central bore therein with first, second and third diameter segments, said first diameter segment being oriented adjacent said supply port, said second diameter segment being greater in diameter than a diameter of said first diameter segment and being oriented between said first diameter segment and said control port, said third diameter segment being greater in diameter than a diameter of said second diameter segment and oriented between said first and second diameter segments, said second diameter segment defining a sensing land at an edge thereof remote from said control port; an elongate spool reciprocally received in said central bore, said spool having a base diameter and a seal land having a primary diameter that is greater than said base diameter and is in a close sliding tolerance fit relation to and in the first diameter segment of said bore to form a sliding seal, said spool having an annular spool ring having a fourth diameter that is greater in diameter than a diameter of said primary diameter and slightly less than said second diameter segment of said bore and being oriented adjacent said sensing land to form a gap between a perimeter of said spool ring and said sensing land to cause a pressure drop across said gap in response to a flow of fluid from said pressure port through said gap to said control port; a servomotor having an output member connected to a first end of said elongate spool and configured to reciprocate said spool within said bore, said servomotor having an output force characteristic as said output member is stroked lengthwise of said bore; and a spring oriented in said bore and against an abutment and engaging a second end of said spool remote from said first end, said spring having a spring force that is configured to oppose, along with a pressurized fluid acting on a side of said spool ring remote from said control port, said output force from said servomotor causing a lengthwise movement of said spool in said bore, a magnitude of said pressure drop across said gap combined with said spring force determining a pressure balanced location to which said spool is moved in response to said output force from said servomotor to thereby control the rate of flow of hydraulic fluid from said pressure port to said to said control port.