Hydraulic control means

• US 6,192,936 B1
• Filed: 03/17/1999
• Issued: 02/27/2001
• Est. Priority Date: 03/20/1998
• Status: Expired due to Fees

• Current Assignee: Aeroquip-Vickers Incorporated (Eaton Corporation PLC.)
• Original Assignee: Aeroquip-Vickers Incorporated (Eaton Corporation PLC.)
• Inventors: Dawson, Clive
• Primary Examiner(s): Michalsky, Gerald A.
• Application Number:
  US09/271,000
• Time in Patent Office: 713 Days
• Field of Search: 914/33, 137/596.14, 137/625.6, 137/625.61
• US Class Current: 137/625.6
• CPC Class Codes: B62D 11/183 Control systems therefor
• CPC Class Codes: F15B 13/0402 for linearly sliding valves, e.g. spool valves
• CPC Class Codes: F15B 13/0422 with manually-operated pilot valves, e.g. joysticks
• CPC Class Codes: Y10T 137/86582 Pilot-actuated
• CPC Class Codes: Y10T 137/87193 Pilot-actuated

Abstract

A hydraulic remote control (HRC) valve including a main spool valve and a pilot pressure control valve. A lever is operatively connected to the pilot valve whereby to provide “finger tip” control of the main spool valve. The HRC has an inverting output, whereby movement of the lever away from a neutral position causes a decrease in hydraulic pressure supplied to a hydraulic clutch. In practice, two HRC'"'"'s according to the invention are embodied in a single housing. The HRC of the invention is of use in controlling the hydraulic steering clutches of tracked vehicles.

Claims

1. A hydraulic control device comprising:

a main hydraulic valve adapted to provide a hydraulic output pressure;

a pilot pressure control valve in fluid communication with the main hydraulic valve and configured to control the output pressure of the main valve such that an increase in operating pressure of the pilot valve causes a decrease in the output pressure of the main valve, wherein the pilot valve includes a closure member;

a biasing member engaging the closure member of the pilot valve;

a manually operable member movable to at least three positions to vary the operating pressure to at least three levels and thereby inversely control the output pressure of the main valve between at least three corresponding levels, wherein said inverse control is provided by the manually operable member acting on the biasing member;

wherein the operating pressure of the pilot valve is controlled by the manually operable member imparting movement to the pilot valve;

wherein the pilot valve and manually operable member are configured such that, when the manually operable member is in a rest position in the absence of manual control, a net force urges the pilot valve to an open position so as to allow fluid to flow freely past the pilot valve to thereby create minimum operating pressure of the pilot valve and maximum output pressure of the main valve; and

wherein manual movement of the manually operable member away from the rest position imparts movement to the pilot valve toward a closed position to thereby increase the operating pressure of the pilot valve and decrease the output pressure of the main valve.

2. A device according to claim 1, wherein the pilot valve is a pressure-relief valve.

3. A device according to claim 2, wherein the pressure relief valve is a poppet valve.

4. A device according to claim 1, wherein:

the pilot valve is a poppet pressure-relief valve;

wherein the biasing member comprises a valve spring and the manually operable member comprises a return spring, and wherein the valve spring and the return spring are adapted to generate the net force.

5. A device according to claim 1, wherein the main valve is a spool valve.

6. A device according to claim 5, wherein the spool valve includes a spool having a first end, and pressure fluid is applied to the first end of the spool through a restrictor.

7. A device according to claim 1, wherein:

the main valve is a spool valve; and

the output of the main valve is fed back to a first end of the spool of that valve over a first portion of the overall cross-section of the spool, wherein pressure fluid controlled by the pilot valve is applied to a second portion of the overall cross-section of the spool, at the first end, the force generated by these pressures being balanced by a spring force acting on a second end of the spool.

8. A device according to claim 1, wherein:

the main valve is a spool valve;

the output of the main valve is fed back to a first end of the spool of that valve over a first portion of the overall cross-section of the spool, wherein pressure fluid controlled by the pilot valve is applied to a second portion of the overall cross-section of the spool, at the first end, the force generated by these pressures being balanced by a spring force acting on a second end of the spool; and

said first and second portions of the overall cross-section of the spool are each 50%.

9. A device according to claim 1, wherein:

the main valve is a spool valve;

the output of the main valve is fed back to a first end of the spool of that valve over a first portion of the overall cross-section of the spool, wherein pressure fluid controlled by the pilot valve is applied to a second portion of the overall cross-section of the spool, at the first end, the force generated by these pressures being balanced by a spring force acting on a second end of the spool; and

said first and second portions of the overall cross-section of the spool are different from one another and total approximately 100% of the cross-section.

10. A device according to claim 1, wherein:

the main valve is a spool valve;

the output of the main valve is fed back to a first end of the spool of that valve over a first portion of the overall cross-section of the spool, wherein pressure fluid controlled by the pilot valve is applied to a second portion of the overall cross-section of the spool, at the first end, the force generated by these pressures being balanced by a spring force acting on a second end of the spool; and

a spring having a substantially constant rate acts upon the second end of the spool of the main valve.

11. A device according to claim 10, wherein the substantially constant rate spring has a relatively low rate.

12. Hydraulic control means for the hydraulic clutches of a tracked vehicle, comprising two hydraulic control devices according to claim 1 mounted in a common housing.

13. Control means according to claim 12, wherein the housing is a block of material drilled to provide fluid flow passages.

14. A hydraulic control device comprising:

a main hydraulic valve adapted to provide a hydraulic output pressure;

a pilot pressure control valve in fluid communication with the main hydraulic valve and configured to control the output pressure of the main valve such that an increase in operating pressure of the pilot valve causes a decrease in the output pressure of the main valve;

a manually operable member movable to at least three positions to vary the operating pressure to at least three levels and thereby inversely control the output pressure of the main valve between at least three corresponding levels;

wherein the pilot valve comprises a poppet pressure-relief valve; and

wherein the operating pressure of the poppet pressure-relief valve is controlled by the manually-operable member acting on a valve spring engaging a closure member of the poppet pressure-relief valve, wherein the member comprises a return spring, and wherein the valve spring and the return spring are adapted such that a net force urges the poppet pressure-relief valve to an open position in the absence of manual control.

15. A hydraulic control device comprising:

a main hydraulic valve adapted to provide a hydraulic output pressure;

a pilot pressure control valve in fluid communication with the main hydraulic valve and configured to control the output pressure of the main valve such that an increase in operating pressure of the pilot valve causes a decrease in the output pressure of the main valve;

a manually operable member movable to at least three positions to vary the operating pressure to at least three levels and thereby inversely control the output pressure of the main valve between at least three corresponding levels;

wherein the main valve comprises a spool valve; and

wherein the output of the main valve is fed back to a first end of the spool of that valve over a first portion of the overall cross-section of the spool, wherein pressure fluid controlled by the pilot valve is applied to a second portion of the overall cross-section of the spool, at the first end, the force generated by these pressures being balanced by a spring force acting on a second end of the spool.

16. The device as recited in claim 15, wherein the first and second portions of the overall cross-section of the spool total approximately 100% of the total cross-section.

17. The device as recited in claim 15, further comprising:

a spring having a substantially constant rate acting upon the second end of the spool of the main valve.