Fluid handling – Systems – Supply and exhaust
Patent
1996-09-10
1998-03-10
Michalsky, Gerald A.
Fluid handling
Systems
Supply and exhaust
137312, 137884, F15B 1308
Patent
active
057250227
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a stack type direction control valve to be employed in a pressurized fluid supply system for supplying a discharged pressurized fluid of a hydraulic pump to a plurality of actuators. More specifically, the invention relates to a direction control valve for constructing a direction control apparatus by stacking a plurality of direction control valves with mating mateable surfaces thereof and connecting therebetween.
BACKGROUND ART
As a pressurized fluid supply system for supplying a discharged pressurized fluid of a single hydraulic pump to a plurality of actuators, one disclosed in Japanese Unexamined Utility Model Publication (Kokai) No. Heisei 5-42703 has been known.
As shown in FIG. 1, the disclosed system is provided with a plurality of direction control valves 3 in a discharge passage 2 of a hydraulic pump 1, each of which the direction control valves 3 is provided with a pressure compensation valve 6 having a check valve portion 4 and a pressure reduction valve portion 5 at the inlet side thereof. A load pressure is introduced into a load pressure detecting passage 7 by the pressure reduction valve portion 5. Then, a direction control valve 8 for adjustment of the pump is switched by the load pressure and a pump discharge pressure in the discharge passage 2 and the pump discharge pressure is supplied to a servo cylinder 9. Thus, a displacement of the hydraulic pump 1 is controlled.
As the conventional direction control valve 3 to be employed in such pressurized fluid supply system, one disclosed in Japanese Unexamined Utility Model Publication No. Heisei 5-42703 has been known.
As shown in FIGS. 2 and 3, the direction control valve is constructed by forming a spool bore 11, a check valve bore 12 and a pressure reduction valve bore 13 in a valve block 10. The valve block 10 is further formed with an inlet port 14, first and second load pressure detecting ports 15 and 16, first and second actuator ports 17 and 18, first and second tank ports 19 and 20, and a tank confluence port 21 respectively opening to the spool bore 11. On a mateable surface of the valve block 10 to be mated with another valve block, a recessed groove 22 communicated with the first and second tank ports 19 and 20 and the tank confluence port 21 is formed. A main spool 23 for establishing and blocking communication of respective ports is disposed in the spool bore 11. Thus, the direction control valve is formed. The valve block 10 is further formed with a pump port 24 opening to the check valve bore 12, and a fluid passage 25 for communicating the check valve bore to the inlet port 14. A spool 26 which establishes and blocks communication between the pump port 24 and the fluid passage 25 and stops at the communication blocking position, is disposed within the check valve bore 12. Thus, the check valve portion 4 is formed. Furthermore, the valve block 10 is formed with first and second ports 27 and 28 opening to the pressure reduction valve bore 13. A spool 29 is disposed within the pressure reduction valve bore 13 for defining first pressure chamber 30 and a second pressure chamber 31 at both ends thereof. The first pressure chamber 30 is communicated with the second load pressure detecting port 16 and the second pressure chamber 31 is communicated with the second port. The spool 29 is biased in one direction by a spring 32 to urge the spool 26 of the check valve 4 to the communication blocking position. Thus, the pressure reducing valve portion 5 is formed. Then, the pressure compensation valve 6 is formed with the pressure reducing valve portion 5 and the check valve portion 4.
In order to form the stack type direction control valve employing such direction control valves, the mateable surfaces of the valve blocks of a plurality of direction control valves are mated and connected for establishing communication between pump ports 24, between the first ports 27 and between second ports 28, as shown in FIG. 4. Also, respective of the first and second tank ports 19 and 20 are
REFERENCES:
patent: 3194265 (1965-07-01), Tennis
patent: 3464444 (1969-09-01), Tennis
patent: 3881512 (1975-05-01), Wilke
patent: 4430927 (1984-02-01), Turnbull
patent: 5485864 (1996-01-01), Takeuchi et al.
Ikei Kazunori
Taka Keisuke
Kananen Ronald P.
Komatsu Ltd.
Michalsky Gerald A.
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