Pilot solenoid control valve and hydraulic control system using same

A hydraulic control valve assembly comprising:

• a distribution block having a pump supply passage, a tank passage and a work port;
• and
• first and second pilot operated control valves each including:
• (a) a body defining an inlet and an outlet with a valve seat therebetween;
• (b) a main valve poppet selectively engaging the valve seat to control flow of fluid between the inlet and the outlet, and forming a control chamber within the body on a side remote from the valve seat;
• (c) an aperture in the main valve poppet with an opening into the control chamber, the aperture having an interior end in fluid communication with the inlet;
• (d) a pilot passage formed in the main valve poppet, and comprising an inlet section extending between the inlet and the control chamber and comprising an outlet section providing a fluid path between the aperture and the outlet;
• (e) a pilot poppet with a body which selectively seals the opening of the aperture, and having a pressure balancing stem attached to the body and extending into the aperture, the pressure balancing stem having a recess which is acted upon by pressure from the outlet section and having an end which is continuously acted upon by pressure from the inlet section;
• and
• (f) an actuator operably coupled to move the pilot poppet with respect to the main valve poppet;
• wherein the first pilot operated control valve is mounted in the distribution block with the inlet in communication with the pump supply passage and the outlet in communication with the work port, and the second pilot operated control valve is mounted in the distribution block with the inlet in communication with the work port and the outlet in communication with the tank passage.

A hydraulic control valve assembly comprising:

• a distribution block having a pump supply passage, a tank passage, a load sense passage, a first work port and a second work port;
• first and second pilot operated supply valves each including:
• (a) a first body defining a first inlet and a first outlet with a first valve seat therebetween,
• (b) a first main valve poppet selectively engaging the first valve seat to control flow of fluid between the first inlet and the first outlet, and forming a first control chamber within the first body on a side remote of the first main valve poppet from the first valve seat,
• (c) a first aperture in the first main valve poppet with an opening into the first control chamber, the first aperture having an interior end in fluid communication with the first inlet,
• (d) a first pilot passage formed in the first main valve poppet, and comprising an first inlet section extending between the first inlet and the first control chamber and comprising a first outlet section providing a fluid path between the first aperture and the first outlet,
• (e) a first pilot poppet with a first poppet body which selectively seals the opening of the first aperture, with a first pressure balancing stem attached to the first poppet body and extending into the first aperture, the first pressure balancing stem having a first recess which is acted upon by pressure from the first outlet section and having an end which is acted upon by pressure from the first inlet section,
• (f) a pressure compensator with in the first body in communication with the load sense passage and closing fluid communication between the first inlet and first outlet in response to pressure in the load sense passage exceeding pressure from the first inlet, and
• (g) a first actuator operably coupled to move the first pilot poppet,
• wherein the first pilot operated supply valve is mounted in the distribution block with its first inlet in communication with the pump supply passage and its first outlet in communication with the first work port, and the second pilot operated supply valve is mounted in the distribution block with its first inlet in communication with the pump supply passage and its first outlet in communication with the second work port;
• and
• first and second pilot operated return valves each including:
• (h) a second body defining a second inlet and a second outlet with a second valve seat therebetween,
• (i) a second main valve poppet selectively engaging the second valve seat to control flow of fluid between the second inlet and the second outlet, and forming a second control chamber within the second body on a side remote of the second main valve poppet from the second valve seat,
• (j) a second aperture in the second main valve poppet with an opening into the second control chamber, the second aperture having an interior end in fluid communication with the second inlet,
• (k) a second pilot passage formed in the second main valve poppet, and comprising a second inlet section extending between the second inlet and the second control chamber and comprising a second outlet section providing a fluid path between the second aperture and the second outlet,
• (l) a second pilot poppet with a second poppet body which selectively seals the opening of the second aperture, and having a second pressure balancing stem attached to the second poppet body and extending into the second aperture, the second pressure balancing stem having a recess which is acted upon by pressure from the second outlet section and having an end which is acted upon by pressure from the second inlet section,
• (m) a check valve coupled to the second body to restrict hydraulic fluid flow from the second outlet to the second inlet when pressure at one of the first and second the work ports exceeds pressure at the tank passage, and
• (n) a second actuator operably coupled to move the second pilot poppet,
• wherein the first pilot operated return valve is mounted in the distribution block with its second inlet in communication with the first work port and its second outlet in communication with the tank passage, and the second pilot operated control valve is mounted in the distribution block with its second inlet in communication with the second work port and its second outlet in communication with the tank passage.