Title:
HYDRAULIC CONTROL CIRCUIT
Document Type and Number:
Japanese Patent JP3657024
Kind Code:
B2
Abstract:
PURPOSE: To reduce costs by using a pilot valve as a back pressure regulating valve, and switching the back pressure regulating valve to a throttle position by the use of the pilot pressure controlled by either of proportional solenoids.
CONSTITUTION: A preference valve PV is connected to a pump P, its control flow port 1 is connected to a first circuit system S1, and a surplus flow port 2 is connected to a second circuit system S2. When the discharge of the pump P exceeds a fixed flow rate, the surplus flow rate flows to the second circuit system S2, and when control valves V1 to V3 are neutral the surplus flow returns to a tank T through a neutral passage 16. When either of proportional solenoids 11a, 11b is energized, a specified signal current is allowed to flow to a proportional solenoid 10b, a generated signal pressure is led to a pilot chamber 23a through a shuttle valve 24, the back pressure regulating valve 23 is switched from a free flow position I to a throttle position III, and a pump discharge pressure, which enables a spool valve to make a full stroke, is obtained by the back pressure of the back pressure regulating valve and the pressure in the upstream of the preference valve PV. Since the pilot valve is used as a back pressure regulating valve, costs can be reduced.
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Inventors:
Kazuo Oshima
Application Number:
JP6487195A
Publication Date:
June 08, 2005
Filing Date:
February 28, 1995
Export Citation:
Assignee:
Kayaba Industry Co., Ltd.
International Classes:
B66F9/22; F15B11/16; (IPC1-7): F15B11/16; B66F9/22
Domestic Patent References:
| JP4083908A | ||||
| JP1266303A | ||||
| JP2225178A | ||||
| JP4258513A |
Attorney, Agent or Firm:
Nobuyuki Shima