EP0433454A1 - Hydraulische schaltungsvorrichtung - Google Patents

Hydraulische schaltungsvorrichtung Download PDF

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Publication number
EP0433454A1
EP0433454A1 EP90907487A EP90907487A EP0433454A1 EP 0433454 A1 EP0433454 A1 EP 0433454A1 EP 90907487 A EP90907487 A EP 90907487A EP 90907487 A EP90907487 A EP 90907487A EP 0433454 A1 EP0433454 A1 EP 0433454A1
Authority
EP
European Patent Office
Prior art keywords
pressure
valve
operating
over
hydraulic
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP90907487A
Other languages
English (en)
French (fr)
Other versions
EP0433454B1 (de
EP0433454A4 (en
Inventor
K Kaw. Fact. K.K. Komatsu Seisakusho Shirai
S Kaw. Fact. K.K. Komatsu Seisakusho Shinohara
T Kaw. Fact. K.K. Komatsu Seisakusho Akiyama
T Kaw. Fact. K.K. Komatsu Seisakusho Takiguchi
N Kaw. Fact. K.K. Komatsu Seisakusho Ishizaki
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Komatsu Ltd
Original Assignee
Komatsu Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP12879889A external-priority patent/JPH0826882B2/ja
Priority claimed from JP12879989A external-priority patent/JPH0826883B2/ja
Application filed by Komatsu Ltd filed Critical Komatsu Ltd
Publication of EP0433454A1 publication Critical patent/EP0433454A1/de
Publication of EP0433454A4 publication Critical patent/EP0433454A4/en
Application granted granted Critical
Publication of EP0433454B1 publication Critical patent/EP0433454B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F15B11/161—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load
    • F15B11/165—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load for adjusting the pump output or bypass in response to demand
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
    • F15B11/05—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed specially adapted to maintain constant speed, e.g. pressure-compensated, load-responsive
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2221—Control of flow rate; Load sensing arrangements
    • E02F9/2225—Control of flow rate; Load sensing arrangements using pressure-compensating valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20546—Type of pump variable capacity
    • F15B2211/20553—Type of pump variable capacity with pilot circuit, e.g. for controlling a swash plate
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/25—Pressure control functions
    • F15B2211/253—Pressure margin control, e.g. pump pressure in relation to load pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40515—Flow control characterised by the type of flow control means or valve with variable throttles or orifices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40553—Flow control characterised by the type of flow control means or valve with pressure compensating valves
    • F15B2211/40569—Flow control characterised by the type of flow control means or valve with pressure compensating valves the pressure compensating valve arranged downstream of the flow control means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/455—Control of flow in the feed line, i.e. meter-in control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
    • F15B2211/50518—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using pressure relief valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5158—Pressure control characterised by the connections of the pressure control means in the circuit being connected to a pressure source and an output member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/55—Pressure control for limiting a pressure up to a maximum pressure, e.g. by using a pressure relief valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/605—Load sensing circuits
    • F15B2211/6051—Load sensing circuits having valve means between output member and the load sensing circuit
    • F15B2211/6054—Load sensing circuits having valve means between output member and the load sensing circuit using shuttle valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/605—Load sensing circuits
    • F15B2211/6051—Load sensing circuits having valve means between output member and the load sensing circuit
    • F15B2211/6057—Load sensing circuits having valve means between output member and the load sensing circuit using directional control valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7051—Linear output members
    • F15B2211/7052—Single-acting output members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7058—Rotary output members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders

Definitions

  • This invention relates to a hydraulic circuit means for supplying fluid under pressure discharged by a hydraulic pump to a plurality of hydraulic driving means such as hydraulic motors or hydraulic cylinders or the like (which are referred to simply as “hydraulic actuators” hereinbelow).
  • hydraulic driving means such as hydraulic motors or hydraulic cylinders or the like (which are referred to simply as “hydraulic actuators” hereinbelow).
  • the fluid under pressure discharged by the hydraulic pump 1 is restricted when passing through the second pressure compensating valve 10, and at the same time relieved from the safety valve 12 to the fluid tank, thereby reducing the amount of fluid to be supplied to the second hydraulic actuator 6, thus reducing the operating speed of the second hydraulic actuator 6.
  • the first hydraulic actuator 5 serves as a turning motor for a power shovel and a second hydraulic actuator 6 serves as a boom actuating cylinder, and a boom is moved upwards by the boom actuating cylinder while the upper turning body is being gyrated, the load pressure at the time of starting the turning motor becomes higher than the pressure P0 at which the safety valve 12 is set, whilst the load pressure at the time of starting the boom actuating cylinder becomes lower than the pressure P0 at which the safety valve 12 is set.
  • the area of opening of the second pressure compensating valve 10 is restricted by the pressure P0 at which the safety valve 12 is set, and fluid pressure is relieved from the safety valve 12 to the fluid tank, and in consequence the fluid under pressure to be supplied to the boom actuating cylinder is reduced, thereby reducing the operating speed of the boom actuating cylinder, which results in reduction in the upwardly moving speed of the boom, thus causing insufficiency in the amount of upward movement thereof.
  • the present invention has been made in view of the above-mentioned circumstances, and has for its object to provide a hydraulic circuit means arranged such that by changing over one operating valve for the full stroke and at the same time another operating valve one pressure compensating valve is supplied with the load pressure in the hydraulic actuator connecting with the pressure compensating valve.
  • a hydraulic circuit means comprising: a plurality of operating valves connected to a discharge passage of a hydraulic pump, the operating valves each supplying fluid under pressure to a plurality of hydraulic actuators, each of the operating valves having a pressure compensating valve provided on the side of the outlet thereof, each of the pressure compensating valves being arranged to be set by the load pressure in the hydraulic actuator kept at the highest pressure characterized in that it comprises a compensation pressure change-over valve provided in a circuit which supplies load pressure to either one of the pressure compensating valves the compensation pressure change-over valve having a first position supplying the highest load pressure, and a second position supplying the load pressure in the hydraulic actuator connected to the pressure compensating valve; and it further comprises a means for holding the compensation pressure change-over valve normally at the first position and changing over the compensation pressure change-over valve to the second position when the operating valve connected to the pressure compensating valve is changed over for the full stroke, and at the
  • the present invention provides a hydraulic control unit comprising a compensation pressure change-over valve in a fluid conduit which supplies load pressure to one pressure compensating valve, the arrangement being made such that, when one of the operating valves is changed over for the full stroke and at the same time the operating valve is changed over, the compensation pressure change-over valve is changed over so as to supply the load pressure in the hydraulic actuator connected to the compensation pressure change-over valve to the spring chamber of the above-mentioned pressure compensating valve.
  • the pressure compensating function of one of the pressure compensating valves is enhanced temporarily by introducing the load pressure in the hydraulic actuator so as to supply a large quantity of fluid under pressure to the hydraulic actuator counnected to the pressure compensating valve so that the operating speed of the hydraulic actuator can be increased.
  • Fig. 1 is a hydraulic circuit diagram showing a prior art example.
  • Fig. 2 is a hydraulic circuit diagram showing a first embodiment of the present invention.
  • Fig. 3 is a hydraulic circuit diagram showing a second embodiment of the present invention.
  • a spring chamber 9a of a first pressure compensating valve 9 is connected with an outlet 20a of a first shuttle valve 20, and a first inlet 20b and a second inlet 20c of the latter are connected with a first pilot path 21 and a second pilot path 22, respectively.
  • the second pilot path 22 is connected with a spring chamber 10a of a second pressure compensating valve 10, an outlet 23a of a second shuttle valve 23, and a displacement controlling member 1a of a hydraulic pump 1, respectively.
  • a first inlet 23b and a second inlet 23c of the above-mentioned second shuttle valve 23 are connected with a third pilot path 24 and a fourth pilot path 25, respectively.
  • the third pilot path 24 and the first pilot path 21 are controlled to be connected by a compensation pressure change-over valve 26 with a first circuit 7, and the fourth pilot path 25 is connected with a second circuit 8.
  • the above-mentioned compensation pressure change-over valve 26 has a first position 1 where the first circuit 7 is connected with the third pilot path 24, and the first pilot path 21 is conencted with a fluid tank or reservoir thereby transmitting a load pressure P1 generated by a first hydraulic actuator 5 to the second shuttle valve 23, and a second position II where the first circuit 7 is connected with the first pilot path 21, and the third pilot path 24 is disconnected, thereby transmitting the load pressure P1 from the first hydraulic actuator 5 to the first shuttle valve 20.
  • the compensation pressure change-over valve 26 is normally held by a spring 26a at its first position I, and changed over to its second position II when its pilot pressure receiving portion 26b is supplied with a pilot pressure.
  • the pilot pressure receiving portion 26b is supplied with a pilot pressure for changing over a second operating valve 4.
  • the pilot pressure for changing over the second operating valve 4 is proportional to the operating stroke of a change-over lever. The arrangement is made such that when the change-over lever is operated for the full stroke to change-over the second operating valve 4 for the full stroke, the pilot pressure will reach its maximum value so that the compensation pressure change-over valve 26 may assume its second position II against the biasing force of the spring 26a.
  • the pilot pressure for changing over the second operating valve 4 will reach a maximum value to allow the compensation pressure change-over valve 26 assume its second position II so that the load pressure P1 from the first hydraulic actuator 5 flows into through the first pilot path 21 into the first shuttle valve 20 and is compared by the latter with the load pressure P2 from the second hydraulic actuator 6, and as a result of the comparison, higher load pressure is transmitted to the spring chamber 9a of the first pressure compensating valve 9.
  • first and second pressure compensating valves 9 and 10 are pressure-compensated by their respective load pressures P1 and P2 and the load pressure P2 is supplied to the pump displacement controlling unit 1a as a load sensing pressure, the pump delivery pressure will become the load pressure P2 plus the load sensing pressure differential, with the result that there is no relief loss from a safety valve 12 and the amount of fluid passing through the second pressure compensating valve 10 will increase, thereby increasing the amount of fluid to be supplied to the second hydraulic actuator 6, and hence, increasing the operating speed.
  • the pilot pressure for changing over the second operating valve 4 will not reach its maximum value, and the compensation pressure change-over valve 26 is held by its spring 26a at its first position I.
  • the compensation pressure change-over valve 26 is held at its first position I so that the load pressure P1 from the first hydraulic actuator 5 acts on the spring chamber 10a of the second pressure compensating valve 10 the through the second shuttle valve 23, thereby compensating the second pressure compensating valve 10.
  • the second pressure compensating valve 10 is pressure-compensated by its own load pressure P2, thereby increasing the area of the opening thereof and starting the turning motor by the load pressure of the boom.
  • the second pressure compensating valve 10 is pressure-compensated by a higher load pressure, and therefore when the hydraulic actuator is subjected to heavy load while excavating the earth by turning the upper turning body and contacting one side surface of the bucket with one side surface of the hole to the digged, guick operation of the boom in the fine control zone can be prevented.
  • the compensation pressure change-over valve 26 of a pilot pressure actuated type is used, however, it may be of a solenoid operated type wherein it is actuated by supplying to its solenoid electric current whose value is in proportion to the operating stroke of the operating valve.
  • the compensation pressure change-over valve 36 is normally held by the resiliency of its spring at its first position I where the output pressure from the shuttle valve 30 is supplied to the spring chamber 10a of the second pressure compensating valve 10.
  • the second pressure compensating valve 10 is supplied with a pilot pressure through the second circuit 8, it is changed over to its second position II where the pressure in the second circuit 8, i.e., the load pressure P2 from the second hydraulic actuator 6 is supplied to the spring chamber 10a of the second pressure compensating valve 10.
  • the above-mentioned compensation pressure change-over valve 36 has a pilot circuit 32 which is connected through a shuttle valve 33 with a pilot circuit 34 for changing over the first operating valve 3.
  • the pilot circuit 32 is provided with a change-over valve 35.
  • the above-mentioned change-over valve 35 is normally held by the resiliency of its spring at its closed position III where the pilot circuit 32 is connected with the fluid tank or reservoir.
  • the change-over valve 35 receives a pilot pressure, it is changed over to its open position IV where the pilot circuit 32 is connected with the shuttle valve 33.
  • the pilot pressure receiving portion 35a of the change-over valve 35 is supplied with a pilot pressure for changing over the second operating valve 4, whose valve is proportional to the operating stroke of the change-over lever.
  • the pilot pressure will reach the maximum value when the change-over lever is operated for the full stroke to change over the second operating valve 4 for the full stroke.
  • the arrangement is made such that when the change-over valve 35 receives the maximum value it is changed over to the open position IV against the resilient force of the spring 35b.
  • the pilot pressure for changing over the second operating valve 4 is supplied to the pilot pressure receiving portion 35a of the change-over valve 35 so as to change over the second operating valve 4, and when the pilot pressure reaches the maximum value the change-over valve 35 is changed over to its open position IV. Simultaneously therewith, the pilot pressure for changing over the first operating valve 3 in the pilot circuit 34 will flow through the shuttle valve 33 into the pilot circuit 32. The pilot pressure is supplied through the change-over valve 35 into the compensation pressure change-over valve 36 so as to cause the change-over valve 36 to assume its second position II.
  • the pilot pressure for changing over the second operating valve 10 will not reach its maximum value, so that the change-over valve 35 is held by its spring 35b at its closed position III, and as a result, even if the first and second operating valves 3 and 4 are operated at the same time, the compensation pressure change-over valve 36 is held at its first position I so as to transmit the load pressure P1 from the first hydraulic actuator 5 to the spring chamber 10a of the second pressure compensating valve 10 to thereby compensate the latter.
  • the second pressure compensating valve 10 is not pressure-compensated and the area of the opening thereof is increased so that no fluid under pressure is relieved from the safety valve 12 and excessive load pressure is not applied to the turning motor at the time of starting it, thereby supplying a large quantity of fluid under pressure to the boom actuating cylinder, thus increasing the upwardly moving speed of the boom and preventing the amount of upward movement of the boom from becoming insufficient.
  • the second pressure compensating valve is pressure-compensated by a higher load pressure, and therefore when the hydraulic actuator is subjected to heavy load while excavating the earth by turning the upper turning body and cotacting one side surface of the bucket with one side surface of the hole to be digged out, quick operation of the boom in the fine control zone can be prevented.
  • the compensation pressure change-over valve 36 and the change-over valve 35 which are of a pilot pressure actuated type, are used, however, it is needless to say that they may be of a solenoid actuated type, wherein they are actuated by supplying their solenoids with electric current whose value is proportional to the operational stroke of their respective operating valves.
EP90907487A 1989-05-24 1990-05-24 Hydraulische schaltungsvorrichtung Expired - Lifetime EP0433454B1 (de)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
JP12879889A JPH0826882B2 (ja) 1989-05-24 1989-05-24 油圧回路
JP12879989A JPH0826883B2 (ja) 1989-05-24 1989-05-24 油圧回路
JP128798/89 1989-05-24
JP128799/89 1989-05-24
PCT/JP1990/000667 WO1990014519A1 (en) 1989-05-24 1990-05-24 Hydraulic circuit apparatus

Publications (3)

Publication Number Publication Date
EP0433454A1 true EP0433454A1 (de) 1991-06-26
EP0433454A4 EP0433454A4 (en) 1993-04-28
EP0433454B1 EP0433454B1 (de) 1996-02-21

Family

ID=26464382

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90907487A Expired - Lifetime EP0433454B1 (de) 1989-05-24 1990-05-24 Hydraulische schaltungsvorrichtung

Country Status (4)

Country Link
EP (1) EP0433454B1 (de)
KR (1) KR920701695A (de)
DE (1) DE69025462T2 (de)
WO (1) WO1990014519A1 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0550257A1 (de) * 1991-12-25 1993-07-07 Kayaba Industry Co., Ltd. Einrichtung zur Steuerung mehrerer Servomotoren
EP1070852A3 (de) * 1999-07-17 2004-01-28 Agco GmbH & Co. Hydraulisches System einer Arbeitsmaschine

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19904616A1 (de) * 1999-02-05 2000-08-10 Mannesmann Rexroth Ag Steueranordnung für wenigstens zwei hydraulische Verbraucher und Druckdifferenzventil dafür

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1274748A (en) * 1987-02-19 1990-10-02 Steven Harold Johnson Balanced hydraulic propulsion system
JPH0611706A (ja) * 1992-06-26 1994-01-21 Seiko Epson Corp 防眩フィルム及びその製造方法及び防眩フィルムを用いた表示装置

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9014519A1 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0550257A1 (de) * 1991-12-25 1993-07-07 Kayaba Industry Co., Ltd. Einrichtung zur Steuerung mehrerer Servomotoren
EP0684387A3 (de) * 1991-12-25 1996-10-30 Kayaba Industry Co Ltd Lastdruckkompensierte hydraulische Steuereinrichtung.
EP0684389A3 (de) * 1991-12-25 1996-10-30 Kayaba Industry Co Ltd Steuereinrichtung für hydraulisches System mit mehreren Verbrauchern.
EP0684388A3 (de) * 1991-12-25 1996-11-06 Kayaba Industry Co Ltd Lastdruckkompensierte hydraulische Steuereinrichtung.
EP1070852A3 (de) * 1999-07-17 2004-01-28 Agco GmbH & Co. Hydraulisches System einer Arbeitsmaschine

Also Published As

Publication number Publication date
WO1990014519A1 (en) 1990-11-29
EP0433454B1 (de) 1996-02-21
DE69025462T2 (de) 1996-09-26
EP0433454A4 (en) 1993-04-28
KR920701695A (ko) 1992-08-12
DE69025462D1 (de) 1996-03-28

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