EP0059471A2
Expired / Lapsed
EP
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Hydrostatic drive system for civil engineering and construction machinery
Assignee: Hitachi Construction Machinery Co Ltd
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Filing: 1982-03-02
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Granted: —
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Expires: 2002-03-02
Abstract
Abstract A hydraulic drive system (2) for civil engineering and construction machinery in which at least first and second hydraulic circuits (8 and 10) having at least first and second hydraulic pumps (4 and 6), respectively, are provided for driving a plurality of actuators such as left and right travelling actuators (56 and 58), a boom actuator (50) and an arm actuator (52). The first circuit has in its first valve group (16) a first travelling directional control valve (32) for one of the left and right travelling actuators, a first boom directional control valve (26) for the boom actuator and a first arm directional control valve for the arm actuator (52), the first boom and arm valves being connected to the first pump in a position upstream of the first travelling valve so as to be able to receive a hydraulic fluid supply from the first pump by taking priority over the first travelling valve. The second circuit has in its second valve group (18) a second travelling directional control valve (38) for the other of the left and right travelling actuators and a second boom directional control valve (44) for the boom actuator and/or a second arm directional control valve (40) for the arm actuator, the second travelling valve being connected to the second pump in a position upstream of the second boom valve and/or the second arm valve so as to be able to receive hydraulic fluid supply from the second pump by taking priority over the second valves. A bypass circuit (62) having a bypass line (60) extending between the second pump and the one travelling actuator is arranged whereby a hydraulic fluid supply from the second pump can be received by the first travelling valve when at least one of the valves of the first group upstream of the first travelling valve (32) which include the boom and arm valves (26, 28) is actuated.
Inventors
- 👤 Nobuya Okabe
- 👤 Fumiki Nakagiri
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 16:52
CPC Classifications
E; E02; E02F; E02F9/00; E02F9/20; E02F9/22; E02F9/2221; E02F9/2239; E02F9/2278; E02F9/2292; F; F15; F15B; F15B11/00; F15B11/16; F15B11/17; F15B2211/00; F15B2211/20; F15B2211/205; F15B2211/20576; F15B2211/30; F15B2211/305; F15B2211/3056; F15B2211/30565; F15B2211/3059; F15B2211/30595; F15B2211/31; F15B2211/3105; F15B2211/3116; F15B2211/32; F15B2211/321; F15B2211/324; F15B2211/40; F15B2211/405; F15B2211/40507; F15B2211/45; F15B2211/455; F15B2211/70; F15B2211/71; F15B2211/7142
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
425 words
A hydraulic drive system for civil engineering and construction machinery comprising at least a first and second hydraulic circuits for driving a plurality of hydraulic actuators, said first circuit including a first hydraulic pump, and a first valve group having a plurality of directional control valves for controlling flow of hydraulic fluid from the first pump to the actuators associated therewith, and said second circuit including a second hydraulic pump, and a second valve group having a plurality of directional control valves for controlling flow of hydraulic fluid from the second pump to the actuators associated therewith, said plurality of actuators including at least left and right travelling actuators, a boom actuator and an arm actuator, wherein: said first valve group includes a first travelling directional control valve for controlling flow of hydraulic fluid to one of the left and right travelling actuators, a first boom directional control valve for controlling flow of hydraulic fluid to the boom actuator, and a first arm directional control valve for controlling flow of hydraulic fluid to the arm actuator, said first boom and arm directional control valves being connected to the first pump in a position upstream of the first travelling directional control valve in the first circuit so as to be able to receive a hydraulic fluid supply from the first pump by taking priority over the first travelling directional control valve; said second valve group includes a second travelling directional control valve for controlling flow of hydraulic fluid to the other of the left and right travelling actuators and a second boom directional control valve for controlling flow of hydraulic fluid to the boom actuator and/or a second arm directional control valve for controlling flow of hydraulic fluid to the arm actuator, said second travelling directional control valve being connected to the second pump in a position upstream of the second boom and/or arm directional control valves in the second circuit so as to be able to receive a hydraulic fluid supply from the second pump by taking priority over the second boom and/or arm directional control valves; and the system further comprises a bypass circuit including a bypass line extending between the second pump and the one travelling actuator, said bypass circuit being effective to allow a hydraulic fluid supply from the second pump to be received by the first travelling actuator when at least one of the directional control valves of the first valve group upstream of the first travelling directional control valve which include the boom and arm directional control valves is actuated.
Claim 2
Dependent Claim
425 words
A hydraulic drive system for civil engineering and construction machinery comprising at least a first and second hydraulic circuits for driving a plurality of hydraulic actuators, said first circuit including a first hydraulic pump, and a first valve group having a plurality of directional control valves for controlling flow of hydraulic fluid from the first pump to the actuators associated therewith, and said second circuit including a second hydraulic pump, and a second valve group having a plurality of directional control valves for controlling flow of hydraulic fluid from the second pump to the actuators associated therewith, said plurality of actuators including at least left and right travelling actuators, a boom actuator and an arm actuator, wherein: said first valve group includes a first travelling directional control valve for controlling flow of hydraulic fluid to one of the left and right travelling actuators, a first boom directional control valve for controlling flow of hydraulic fluid to the boom actuator, and a first arm directional control valve for controlling flow of hydraulic fluid to the arm actuator, said first boom and arm directional control valves being connected to the first pump in a position upstream of the first travelling directional control valve in the first circuit so as to be able to receive a hydraulic fluid supply from the first pump by taking priority over the first travelling directional control valve; said second valve group includes a second travelling directional control valve for controlling flow of hydraulic fluid to the other of the left and right travelling actuators and a second boom directional control valve for controlling flow of hydraulic fluid to the boom actuator and/or a second arm directional control valve for controlling flow of hydraulic fluid to the arm actuator, said second travelling directional control valve being connected to the second pump in a position upstream of the second boom and/or arm directional control valves in the second circuit so as to be able to receive a hydraulic fluid supply from the second pump by taking priority over the second boom and/or arm directional control valves; and the system further comprises a bypass circuit including a bypass line extending between the second pump and the one travelling actuator, said bypass circuit being effective to allow a hydraulic fluid supply from the second pump to be received by the first travelling actuator when at least one of the directional control valves of the first valve group upstream of the first travelling directional control valve which include the boom and arm directional control valves is actuated.
Claim 3
Dependent Claim
65 words
A hydraulic drive system as claimed in claim 1, wherein said bypass circuit includes an on-off valve connected in said bypass line, said on-off valve being normally disposed in a closed position and adapted to'be brought to an open position conjointly with actuation of at least one of the directional control valves of said first valve group upstream of said first travelling directional control valve.
Claim 4
Dependent Claim
26 words
A hydraulic drive system as claimed in claim 1 or 2, wherein said bypass line connects said second pump to said first travelling directional control valve.
Claim 5
Dependent Claim
36 words
A hydraulic drive system as claimed in claim 1 or 2, wherein said bypass circuit includes a third travelling directional control valve connected in said bypass line and interlocked with said second travelling directional control valve.
Claim 6
Dependent Claim
29 words
A hydraulic drive system as claimed in claim 1, wherein said second boom and/or arm directional control valves are interlocked with said first boom and arm directional control valves.
Claim 7
Dependent Claim
130 words
A hydraulic drive system as claimed in claim in which said plurality of actuators further includes a swing actuator, whrein said first valve group further includes a swing directional control valve for controlling flow of hydraulic fluid to said swing actuator, said swing directional control valve being connected to said first pump in a position upstream of said fir t arm and travelling directional control valves in said first circuit so as to be able to receive a hydraulic fluid supply from the first pump by taking priority over the first arm and travelling directional control valves, and said first boom directional control valve being connected to the first pump through a second bypass line connected to the first circuit in a position upstream of said swing directional control valve.
Claim 8
Dependent Claim
78 words
A hydraulic drive system as claimed in claim 1 or 6 in which said plurality of actuators further includes a bucket actuator, wherein said second valve group further includes a bucket directional control valve for controlling flow of hydraulic fluid to said bucket actuator, said bucket directional control valve being connected to a third bypass line connected to the second circuit in a position between the second travelling directional control valve and the second arm directional control valve.
Claim 9
Dependent Claim
165 words
A hydraulic drive system as claimed in claim 1 in which said plurality of actuators further includes a swing actuator and a bucket actuator, wherein said first valve group further includes a swing directional control valve for controlling flow of hydraulic fluid to said swing directional control valve, said swing directional control valve being connected to the first pump in a position upstream of said first boom and arm directional control valves in the first circuit so as to be able to receive a hydraulic fluid supply from the first pump by taking priority over the first boom and arm directional control valves, and said second valve group further includes a bucket directional control valve for controlling flow of hydraulic fluid to said bucket actuator, said second boom and bucket directional control valves being connected to fourth and fifth bypass lines, respectively, which are connected to the second circuit in a position between the second travelling directional control valve and second arm directional control valve.
Claim 10
Dependent Claim
96 words
A hydraulic drive system as claimed in claim 1 in which said plurality of actuators further includes a swing actuator, wherein said system further comprises a third hydraulic circuit for driving said swing actuator, said third circuit including a third hydraulic pump and a swing directional control valve for controlling flow of hydraulic fluid to said swing actautor from said third pump, and said first arm directional control valve is connected to the first pump through a sixth bypass line connected to the first circuit in a position upstream of the first boom directional control valve.
Claim 11
Dependent Claim
76 words
A hydraulic drive system as claimed in claim 9 in which said plurality of actuators further includes a bucket actuator, wherein said second valve group further includes a bucket directional control valve for controlling flow of hydraulic fluid to said bucket actuator, said bucket directional control valve being connected to a seventh bypass line connected to the second circuit in a position between the second travelling directional control valve and the second boom directional control valve.
Claim 12
Dependent Claim
54 words
A hydraulic drive system as claimed in claim 1, wherein said first.travelling directional control valve is connected to the first pump through an eighth bypass line connected to the first circuit in a position upstream of the first boom and arm directional control valves, said eighth bypass line having flow restricting means mounted therein.
Claim 13
Dependent Claim
113 words
A hydraulic drive system as claimed in claim 11 in which said plurality of actuators further includes a swing actuator, wherein said first valve group further includes a swing directional control valve for controlling flow of hydraulic fluid to said swing actuator, said swing directional control valve being connected to the first pump in a position upstream of the first travelling directional control valve in the first circuit so as to be able to receive a hydraulic fluid supply from the first pump by taking priority over the first travelling directional control valve, said eighth bypass line being connected to the first circuit in a position upstream of the swing directional control valve.
Claim 14
Dependent Claim
42 words
A hydraulic drive system as claimed in claim 12, wherein said first boom directional control valve is connected to the first pump through a ninth bypass line connected to the first circuit in a position upstream of the swing directional control valve.
Claim 15
Dependent Claim
44 words
A hydraulic drive system as claimed in claim 12, wherein said first arm directional control valve is connected to a tenth bypass line connected to the first circuit in a position between the swing directional control valve and the first boom directional control valve.
Claim 16
Dependent Claim
44 words
A hydraulic drive system as claimed in claim 13, wherein said first arm directional control valve is connected to an eleventh bypass line connected to the first circuit in a position between the swing directional control valve and the first boom directional control valve.
Claim 17
Dependent Claim
52 words
A hydraulic drive system as claimed in claim 12, wherein said first arm directional control valve is connected to the first pump through a twelfth bypass line connected to the first circuit in a position upstream of the swing directional control valve, said twelfth bypass line having flow restricting means mounted therein.
Claim 18
Dependent Claim
52 words
A hydraulic drive system as claimed in claim 13, wherein said first arm directional control valve is connected to the first pump through a thirteenth bypass line connected to the first circuit in a position upstream of the swing directional control valve, said thirteenth bypass line having flow restricting means mounted therein.
Claim 19
Dependent Claim
79 words
A hydraulic drive system as claimed in any one of claims 14-17 in which said plurality of actuators further includes a bucket actuator, wherein said second valve group further includes a bucket directional control valve for controlling flow of hydraulic fluid to said bucket actuator, said bucket directional control valve being connected to a fourteenth bypass line connected to the second circuit in a position between the second travelling directional control valve and the second boom directional control valve.
Claim 20
Dependent Claim
97 words
A hydrualic drive system as claimed in claim 11 in which said plurality of actuators further includes a swing actuator, wherein said system further comprises a third hydraulic fluid circuit for driving said swing actuator, said third circuit including a third hydraulic pump and a swing directional control valve for controlling flow of hydraulic fluid from the third pump to the swing actuator, and said first arm directional control valve is connected to the first pump through a fifteenth bypass line connected to the first circuit in a position upstream of the first boom directional control valve.
Claim 21
Dependent Claim
76 words
A hydraulic drive system as claimed in claim 19 in which said plurality of actuators further includes a bucket actuator, wherein said second valve group further includes a bucket directional control valve for controlling flow of hydraulic fluid to said bucket actuator, said bucket directional control valve being connected to a sixteenth bypass line connected to the second circuit in a position between the second travelling directional control valve and the second boom directional control valve.
References Cited (Backward Citations)
No citation records indexed.
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