Patent EP0087748A1 successfully refreshed from Google Patents.
EP0087748A1
Expired / Lapsed
EP
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Hydraulic circuit system for construction machine
Assignee: Hitachi Construction Machinery Co Ltd
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Filing: 1983-02-23
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Granted: —
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Expires: 2003-02-23
Abstract
Abstract A hydraulic circuit system of a construction machine having first and second hydraulic circuit (8, 10), and a bypass circuit for connecting the first and second circuits together (54). The first circuit includes a first hydraulic pump (4) and a first valve group (14) having a plurality of directional control valves for controlling a flow of hydraulic fluid from the first pump, and the second circuit (10) includes a second hydraulic pump (6) and a second valve group (20) having a plurality of directional control valves for controlling a flow of hydraulic fluid from the second pump. A plurality of actuators (56, 58, 60, 62, 64, 66) are driven by the hydraulic fluid supplied from the first and second pumps through the valves. The valves of the first group include a first travel directional control valve (40) for controlling the first travel actuator (64) connected in tandem with other valves in a position downstream thereof to enable the other valves to have priority in receiving a supply of hydraulic fluid from the first pump (4). The valves of the second group include a second travel directional control valve (44) for controlling a second travel actuator (66) connected in series with other valves of the second valve group in a position upstream thereof through a directional selecting valve to directly receive a supply of hydraulic fluid from the second pump (6) to supply same to the second travel actuator and return hydraulic fluid from the second travel actuator (44) to the second circuit (10 The bypass circuit includes a bypass line for connecting the first travel valve in series with the second travel valve in a position downstream thereof through the selecting valve (52). The selecting valve has first and second positions and is normally in the first position to communicate the second travel valve with the other valves of the second group to supply the hydraulic fluid from the second travel valve to the other valves. When the first travel valve and at least one of the other valves of the second group are simultaneously actuated, the selecting valve is switched to the second position to bring the second travel valve (44) into communication with the first travel valve (40) through the bypass line (54) thereby to supply the hydraulic fluid from the second travel valve (44) to the first travel valves (40).
Inventors
- 👤 Nobuya Okabe
- 👤 Hiroshi Mizushima
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 22:33
CPC Classifications
F; F15; F15B; F15B11/00; F15B11/16; F15B11/17; E; E02; E02F; E02F3/00; E02F3/04; E02F3/28; E02F3/36; E02F3/42; E02F9/00; E02F9/20; E02F9/22; E02F9/2221; E02F9/2239; E02F9/2278; E02F9/2292; F15B2211/00; F15B2211/20; F15B2211/205; F15B2211/2053; F15B2211/20538; F15B2211/30; F15B2211/305; F15B2211/30505; F15B2211/3056; F15B2211/3059; F15B2211/30595; F15B2211/31; F15B2211/3105; F15B2211/3116; F15B2211/36; F15B2211/40; F15B2211/405; F15B2211/40507; F15B2211/455; F15B2211/60; F15B2211/635; F15B2211/6355; F15B2211/70; F15B2211/71; F15B2211/7142; F15B2211/78; F15B2211/781
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
537 words
A hydraulic circuit system for a construction machine comprising first hydraulic circuit means (8), second hydraulic circuit means (10) and bypass circuit means connecting the first and second hydraulic circuit means together, said first hydraulic circuit means (8) including a first hydraulic pump (4) and a first valve group (14) having a plurality of directional control valves (32, 34, 36, 38, 40) for controlling a flow of hydraulic fluid from said first hydraulic pump (4), and said second hydraulic circuit means (10) including a second hydraulic pump (6) and a second valve group (20) having a plurality of directional control valves (44, 46, 48, 50) for controlling a flow of hydraulic fluid from said second hydraulic pump (6), a plurality of actuators (56, 58, 60, 62, 64, 66) being driven by the hydraulic fluid supplied from said first and second hydraulic pumps (4, 6) through said directional control valves of said first and second valve groups (14, 20), wherein said directional control valves of said first valve group (14) in said first hydraulic circuit means (8) include a first travel directional control valve (40) for controlling a first travel actuator (64), said first travel directional control valve being connected in tandem with other valves of the first valve group in a position downstream thereof so that the other directional control valves of the first valve group (14) can take priority in receiving a supply of hydraulic fluid from said first hydraulic pump (4); said directional control valves of said second valve group (20) in said second hydraulic circuit means (10) include a second travel directional control valve (44) for controlling a second travel actuator (66), said second travel directional control valve (44) being connected in series with other valves of the second valve group (20) in a position upstream thereof through a directional selecting valve (52) so that said second travel directional control valve (44) can directly receive a supply of hydraulic fluid from said second hydraulic pump (6) to supply sane to said second travel actuator (66) and returns hydraulic fluid from the second travel actuator (66) to the second hydraulic circuit means (10); said bypass circuit means includes a first bypass line (54) for connecting said first travel directional control valve (40) in series with said second travel directional control valve (44) in a position downstream thereof through said directional selecting valve (52); and said directional selecting valve (52) having first and second positions, said directional selecting valve (52) normally taking the first position to communicate said second travel directional control valve (44) with the other valves of said second valve group to supply hydraulic fluid from said second travel directional control (44) valve to the other valves (46, 48, 50), said directional selecting valve (52) being switched to the second position when said first travel directional control valve (40) and at least one of the other valves of said second valve group (20) are simultaneously actuated to bring said second travel directional control valve (44) into communication with said first travel directional control valve (40) through said first bypass line (54) thereby to supply hydraulic fluid from said second travel directional control valve (44) to said first travel directional control valve (40). (Fig. 1)
Claim 2
Dependent Claim
537 words
A hydraulic circuit system for a construction machine comprising first hydraulic circuit means (8), second hydraulic circuit means (10) and bypass circuit means connecting the first and second hydraulic circuit means together, said first hydraulic circuit means (8) including a first hydraulic pump (4) and a first valve group (14) having a plurality of directional control valves (32, 34, 36, 38, 40) for controlling a flow of hydraulic fluid from said first hydraulic pump (4), and said second hydraulic circuit means (10) including a second hydraulic pump (6) and a second valve group (20) having a plurality of directional control valves (44, 46, 48, 50) for controlling a flow of hydraulic fluid from said second hydraulic pump (6), a plurality of actuators (56, 58, 60, 62, 64, 66) being driven by the hydraulic fluid supplied from said first and second hydraulic pumps (4, 6) through said directional control valves of said first and second valve groups (14, 20), wherein said directional control valves of said first valve group (14) in said first hydraulic circuit means (8) include a first travel directional control valve (40) for controlling a first travel actuator (64), said first travel directional control valve being connected in tandem with other valves of the first valve group in a position downstream thereof so that the other directional control valves of the first valve group (14) can take priority in receiving a supply of hydraulic fluid from said first hydraulic pump (4); said directional control valves of said second valve group (20) in said second hydraulic circuit means (10) include a second travel directional control valve (44) for controlling a second travel actuator (66), said second travel directional control valve (44) being connected in series with other valves of the second valve group (20) in a position upstream thereof through a directional selecting valve (52) so that said second travel directional control valve (44) can directly receive a supply of hydraulic fluid from said second hydraulic pump (6) to supply sane to said second travel actuator (66) and returns hydraulic fluid from the second travel actuator (66) to the second hydraulic circuit means (10); said bypass circuit means includes a first bypass line (54) for connecting said first travel directional control valve (40) in series with said second travel directional control valve (44) in a position downstream thereof through said directional selecting valve (52); and said directional selecting valve (52) having first and second positions, said directional selecting valve (52) normally taking the first position to communicate said second travel directional control valve (44) with the other valves of said second valve group to supply hydraulic fluid from said second travel directional control (44) valve to the other valves (46, 48, 50), said directional selecting valve (52) being switched to the second position when said first travel directional control valve (40) and at least one of the other valves of said second valve group (20) are simultaneously actuated to bring said second travel directional control valve (44) into communication with said first travel directional control valve (40) through said first bypass line (54) thereby to supply hydraulic fluid from said second travel directional control valve (44) to said first travel directional control valve (40). (Fig. 1)
Claim 3
Dependent Claim
76 words
A hydraulic circuit system as claimed in claim 1, wherein the other valves of said first valve group (14) in said first hydraulic circuit means (8) include a swing directional control valve (32) for controlling a swing actuator (56), and a boom directional control valve (34) for controlling a boom actuator (58), said swing directional control valve and said boom directional control valve being connected in parallel with each other through a second bypass line (35).
Claim 4
Dependent Claim
128 words
A hydraulic circuit system as claimed in claim 2, wherein the other valves of said first valve group (14) in said first hydraulic circuit means (8) further include a first arm directional control valve (36) for controlling an arm actuator (60) connected in tandem with said first boom directional control valve (34) in a position downstream thereof, and the other valves of said second valve group (20) in said second hydraulic circuit means (10) include a second arm directional control valve (46) for controlling said arm actuator (60), and a bucket directional control valve (48) for controlling a bucket actuator (62), said second arm directional control valve (46) and said bucket directional control valve (48) being connected in parallel with each other through a third bypass line (47).
Claim 5
Dependent Claim
47 words
A hydraulic circuit system as claimed in claim 1, wherein the other valves of said first valve group (14) in said first hydraulic circuit system (8) are connected in parallel with one another through respective bypass lines (86, 94, 96) each mounting a check valve. (Fig. 3).
Claim 6
Dependent Claim
103 words
A hydraulic circuit system as claimed in claim 1, wherein the other valves of said first valve group in said first hydraulic circuit means include a swing directional control valve (32) for controlling a swing actuator (56), a boom directional control valve (34) for controlling a boom actuator (58), and an arm directional control valve (36) for controlling an arm actuator (60), said swing directional control valve (32), said boom directional control valve (34) and said arm directional control valve (36) being connected in parallel with one another through fourth and fifth bypass lines (35, 94) each mounting a check valve. (Fig. 3)
Claim 7
Dependent Claim
26 words
A hydraulic circuit system as claimed in claim 5, wherein said fifth bypass line for the arm directional control valve further mounts a flow restrictor (88).
Claim 8
Dependent Claim
35 words
A hydraulic circuit system as claimed in claim 6, wherein said arm directional control valve (36) is connected in parallel with said boom directional control valve (34) through a sixth bypass line (86). (Fig. 3)
Claim 9
Dependent Claim
80 words
A hydraulic circuit system as claimed in claim 5, wherein the other valves of said first valve group in said first hydraulic circuit means further include a bucket directional control valve (38) for controlling a bucket actuator (62), said bucket directional control valve (38) being connected in parallel with said swing directional control valve (32), said boom directional control valve (34) and said arm directional control valve (36) through a seventh bypass line (96) mounting a check valve. (Fig. 3)
Claim 10
Dependent Claim
27 words
A hydraulic circuit system as claimed in claim 8, wherein said bypass line (96) for said bucket directional control valve (38) further mounts a flow restrictor (90).
Claim 11
Dependent Claim
91 words
A hydraulic circuit system as claimed in claim 1,further comprising a third hydraulic circuit means (114) including a third hydraulic pump (116), a swing actuator (56) driven by hydraulic fluid from said third hydraulic pump, and a swing directional control valve (32) for controlling a flow of hydraulic fluid supplied from said third hydraulic pump to said swing actuator, and the other valves of said first valve group (104) in said first hydraulic circuit means (102) including a boom directional control valve (34) for controlling a boom actuator (58). (Fig. 4)
Claim 12
Dependent Claim
92 words
A hydraulic circuit system as claimed in claim 10, wherein the other valves of said first valve group (104, in said first hydraulic circuit means (102) further include an arm directional control valve (36) for controlling an arm actuator (60), said arm directional control valve being connected in parallel with said boom directional control valve (34) through an eighth bypass line (106), and the other valves of said second valve group (20) in said second hydraulic circuit means (10) include a bucket directional control valve (48) for controlling a bucket actuator (62).
Claim 13
Dependent Claim
93 words
A hydraulic circuit system as claimed in claim 10, wherein the other valves of said first valve group (104) in said first hydraulic circuit means (102) further include a bucket directional control valve (38) for controlling a bucket actuator (62), said bucket directional (38) control valve being connected in parallel with said boom directional valve through a ninth bypass line (108), and the other valves of said second valve group (20) in said second hydraulic circuit means (10) include an arm directional control valve (4 6 ) for controlling an arm actuator (60).
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