Electrohydraulic valve arrangement

• US 5,868,059 A
• Filed: 05/28/1997
• Issued: 02/09/1999
• Est. Priority Date: 05/28/1997
• Status: Expired due to Term

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Smith, David P.
• Primary Examiner(s): NGUYEN, HOANG M
• Application Number:
  US08/864,607
• Time in Patent Office: 622 Days
• Field of Search: 91/459, 91/461, 91/454, 137/596.16, 251/30.02, 251/33
• US Class Current: 91/454
• CPC Class Codes: F15B 11/006 Hydraulic "Wheatstone bridge" circuits, i.e. with four nodes, P-A-T-B, and on-off or proportional valves in each link
• CPC Class Codes: F15B 11/0426 by controlling the number of pumps or parallel valves switched on
• CPC Class Codes: F15B 11/044 by means in the return line , i.e. "meter out"F15B11/046, F15B11/05 take precedence
• CPC Class Codes: F15B 13/0405 for seat valves, i.e. poppet valves
• CPC Class Codes: F15B 13/0433 the pilot valves being pressure control valves F15B13/0435, F15B13/0436, F15B13/0438 take precedence
• CPC Class Codes: F15B 13/0442 with proportional solenoid allowing stable intermediate positions
• CPC Class Codes: Y10T 137/87209 Electric

Abstract

An electrohydraulic displacement controlled valve module is disposed in a bore of a valve body for controlling fluid flow between first and second ports. A main valve element slideably disposed in the bore is biased to a closed position blocking communications between an annular groove of the valve element and the second port. An actuating chamber defined at one end of the valve element receives pressurized pilot fluid for urging the main valve element toward an open position communicating the first and second ports through the annular groove. A passage communicates the actuating chamber with a control chamber disposed at the other end of the valve element through an orifice. A poppet is disposed within the control chamber and is biased into sealing engagement with an annular valve seat of an outlet port by a feedback spring disposed between the valve element and the poppet. A proportional electromagnetic device is suitable connected to the valve body for controlling the position of the poppet relative to the valve seat to control the fluid pressure in the control chamber.

Claims

1. An electrohydraulic valve arrangement including a valve body having a bore and first and second annular ports axially spaced along and opening into the bore, and an electrohydraulic displacement controlled valve module disposed in the bore for controlling fluid flow between the first and second annular port, the electrohydraulic valve module comprising:

a main valve element slideably disposed within the bore and having an annular groove continuously communicating with the first annular port;

a spring biasing the main valve element to a closed position blocking communication between the annular groove and the second annular port;

an actuating chamber defined at one end of the main valve element and adapted to receive pressurized pilot fluid for urging the main valve element toward an open position communicating the first and second annular ports through the annular groove;

an inlet port communicating with the actuating chamber;

a control chamber disposed at the other end of the main valve element;

passage means for communicating the actuating chamber with the control chamber and including an orifice disposed between the actuating chamber and the control chamber;

an outlet port communicating with the control chamber and defining an annular valve seat;

a poppet disposed within the control chamber;

a feedback spring disposed between the main valve element and the poppet and biasing the poppet into sealing engagement with the annular valve seat; and

a proportional electromagnetic device suitably connected to the valve body for controlling the position of the poppet relative to the valve seat to control the fluid pressure in the control chamber.

2. The electrohydraulic valve module of claim 1 wherein the passage means includes a longitudinally extending passage formed in the main valve element.

3. The electrohydraulic valve module of claim 2 including relief valve means for communicating fluid from the first annular port to the actuating chamber so that the valve element moves to its open position when the pressure in the first annular port exceeds a predetermined value.

4. The electrohydraulic valve module of claim 3 wherein the relief valve means includes a check valve disposed in the inlet port, at least one relief hole communicating the first annular port with the actuating chamber, a relief valve element disposed to block fluid flow through the relief valve hole, and a relief spring biasing the relief valve element to a position blocking flow through the relief hole.

5. The electrohydraulic valve module of claim 4 wherein the relief valve hole is formed in the main valve element and the relief valve element and the relief spring are disposed in the actuating chamber.

6. The electrohydraulic valve module of claim 5 wherein the first annular port is a cylinder port adapted to be connected to a hydraulic cylinder.

7. The electrohydraulic valve module of claim 4 wherein the relief valve means includes passage means defined in the poppet communicating with the control chamber, a pin, a spring disposed to bias the pin into contact with the poppet to block fluid flow through the passage means until pressure in the control chamber exceeds another predetermined level.

8. The electrohydraulic valve module of claim 7 wherein the pin is disposed between the poppet and the electromagnetic device.

9. The electrohydraulic valve module of claim 2 including fluid make-up means for communicating the control chamber to the first annular port so that the main valve element moves to its open position when the fluid pressure in the first annular control port drops below a predetermined level.

10. The electrohydraulic valve module of claim 9 wherein said make-up means includes at least one make-up hole communicating a portion of the passage means between the orifice and the control chamber with the first annular control port, a make-up valve element disposed to block flow through the make-up hole, and a spring biasing the make-up valve element to a position blocking fluid flow through make-up hole.

11. The electrohydraulic valve module of claim 10 wherein the make-up hole is formed in the main valve element and communicates the annular groove with the longitudinally extending passage in the main valve element and the make-up valve element and the make-up spring are disposed within the annular groove.

12. The electrohydraulic valve module of claim 2 including a valve seat defined between the second port and the bore and a conical valve face formed on the main valve element and seated on the valve seat at the closed position of the main valve element.

13. The electrohydraulic valve module of claim 12 wherein the main valve element includes a reduced diameter portion, and an annular poppet disposed on the reduced diameter portion and defining the conical valve face, and an annular retainer removable fixed to the main valve element to retain the annular poppet on the reduced diameter portion.

14. The electrohydraulic valve module of claim 13 including a sleeve disposed on the reduced diameter portion between the poppet and the retainer and slideably disposed in the bore.

15. The electrohydraulic valve module of claim 14 wherein the annular poppet is made from a non-metallic seal material.

16. The electrohydraulic valve module of claim 15 wherein the reduced diameter portion includes a pair of annular grooves and including a pair of elastomeric annular seals disposed in the annular grooves.

17. The electrohydraulic valve module of claim 16 wherein one of the annular grooves is disposed adjacent the annular poppet so that the annular seal in said one annular groove seals against the annular poppet.

18. The electrohydraulic valve module of claim 17 wherein the body includes another bore, a removable adapter seated in the other bore and defining a portion of the first named bore which slideably receives the sleeve.

19. The electrohydraulic valve arrangement of claim 1 wherein the valve body has another bore and third and fourth annular ports opening into the second bore and including a second electrohydraulic valve module disposed within said second bore for controlling fluid flow between the third and fourth annular ports.

20. The electrohydraulic valve module of claim 1 including passage means defined in the poppet communicating with the control chamber, a pin, a spring disposed to bias the pin into contact with the poppet to block fluid flow through the passage means until pressure in the control chamber exceeds a predetermined level.

21. The electrohydraulic valve module of claim 20 wherein the pin is disposed between the poppet and the electromagnetic device.

22. The electrohydraulic valve module of claim 21 including means associated with the electromagnetic device and disposed to permit the release of fluid pressure in the control chamber when the pressure generated force acting on the pin is greater than the force generating capability of the electromagnetic device, but less than said predetermined pressure level.