EP0059471B1 - Système d'entraînement hydrostatique pour machines de travaux publics - Google Patents

Système d'entraînement hydrostatique pour machines de travaux publics Download PDF

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Publication number
EP0059471B1
EP0059471B1 EP19820101590 EP82101590A EP0059471B1 EP 0059471 B1 EP0059471 B1 EP 0059471B1 EP 19820101590 EP19820101590 EP 19820101590 EP 82101590 A EP82101590 A EP 82101590A EP 0059471 B1 EP0059471 B1 EP 0059471B1
Authority
EP
European Patent Office
Prior art keywords
directional control
control valve
boom
pump
travelling
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.)
Expired
Application number
EP19820101590
Other languages
German (de)
English (en)
Other versions
EP0059471A3 (en
EP0059471A2 (fr
Inventor
Nobuya Okabe
Fumiki Nakagiri
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.)
Hitachi Construction Machinery Co Ltd
Original Assignee
Hitachi Construction Machinery Co 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 JP56029320A external-priority patent/JPS57146842A/ja
Priority claimed from JP56087553A external-priority patent/JPS57205636A/ja
Priority claimed from JP57028556A external-priority patent/JPS58146632A/ja
Application filed by Hitachi Construction Machinery Co Ltd filed Critical Hitachi Construction Machinery Co Ltd
Publication of EP0059471A2 publication Critical patent/EP0059471A2/fr
Publication of EP0059471A3 publication Critical patent/EP0059471A3/en
Application granted granted Critical
Publication of EP0059471B1 publication Critical patent/EP0059471B1/fr
Expired legal-status Critical Current

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Classifications

    • 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
    • E02F9/2239—Control of flow rate; Load sensing arrangements using two or more pumps with cross-assistance
    • 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
    • E02F9/2278—Hydraulic circuits
    • E02F9/2292—Systems with two or more pumps
    • 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
    • F15B11/17—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors using two or more pumps
    • 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
    • F15B2211/20576—Systems with pumps with multiple pumps
    • 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
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/3056—Assemblies of multiple valves
    • F15B2211/30565—Assemblies of multiple valves having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-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
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/3056—Assemblies of multiple valves
    • F15B2211/3059—Assemblies of multiple valves having multiple valves for multiple output members
    • F15B2211/30595—Assemblies of multiple valves having multiple valves for multiple output members with additional valves between the groups of valves for multiple 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
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3105—Neutral or centre positions
    • F15B2211/3116—Neutral or centre positions the pump port being open in the centre position, e.g. so-called open centre
    • 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
    • F15B2211/30—Directional control
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/321—Directional control characterised by the type of actuation mechanically
    • F15B2211/324—Directional control characterised by the type of actuation mechanically manually, e.g. by using a lever or pedal
    • 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
    • F15B2211/40507—Flow control characterised by the type of flow control means or valve with constant 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
    • F15B2211/45—Control of bleed-off flow, e.g. control of bypass flow to the return line
    • 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
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders
    • F15B2211/7142—Multiple output members, e.g. multiple hydraulic motors or cylinders the output members being arranged in multiple groups

Definitions

  • This invention relates to hydraulic drive systems for civil engineering and construction machinery, and more particularly it is concerned with a hydraulic drive system suitable for use with civil engineering and construction machinery provided with a plurality of working elements, such as hydraulic shovels.
  • a hydraulic shovel is provided with a plurality of working elements including a swing, left and right travelling members, a boom, an arm and a bucket which are adapted to be driven by respective hydraulic actuators such as a swing motor, left and right travelling motors, a boom cylinder, an arm cylinder and a bucket cylinder of a hydraulic drive system.
  • the hydraulic drive system generally comprises at least two hydraulic circuits each having a hydraulic pump mounted therein, and a valve group comprising a plurality of directional control valves for controlling the flow of hydraulic fluid supplied to the associated actuators from the pump thereby to control the operation of the actuators.
  • the parallel connection of the directional control valves as aforesaid enables the hydraulic circuits to be simplified in construction and permits a plurality of actuators to be simultaneously driven.
  • difficulties are experienced in effecting control accurately because actuator operations would be mutually influenced by the working pressure thereof.
  • the hydraulic shovel is travelling straightforwardly by actuating the left and right travelling motors connected to the two hydraulic pumps respectively, if an attempt is made to actuate the swing motor, boom cylinder, arm cylinder or bucket cylinder connected in parallel with one of the travel motors, then the hydraulic shovel would travel in zigzag fashion.
  • the hydraulic fluid would flow only to the actuator of lower working pressure and the other actuator or actuators would be rendered inoperative.
  • the hydraulic drive system disclosed in this US Patent Specification comprises a first hydraulic circuit and a second hydraulic circuit connected together at specific points therein through a first bypass line, a second bypass line and a third bypass line, one of such two circuits having specific points therein connected together through a fourth bypass line.
  • the system further comprises a control valve and on-off valves associated with the first to third bypass lines and responsive to actuation of the predetermined directional control valves.
  • the boom directional control valve is connected in tandem to the right travelling directional valve on the downstream side of the latter.
  • This arrangement makes it impossible to supply hydraulic fluid simultaneously to the right travelling motor and the boom cylinder, so that it is impossible to perform travelling and boom combined operations.
  • the provision of the fourth bypass line enables hydraulic fluid to be simultaneously supplied to the left travelling motor and the arm cylinder thereby to permit travel and arm combined operations to be performed.
  • the left travelling motor and the arm cylinder would be mutually influenced by the working pressures thereof, so that when the left travelling motor has a lower working pressure the arm would not operate.
  • the working pressure of the left travelling motor drops and makes it impossible for the arm to operate simultaneously.
  • the operator of the hydraulic shovel intends to drive the travelling members forwardly by pulling the arm toward him. In such case, it would be impossible for the hydraulic shovel to escape from the muddy ground because of low working pressure of the travelling motors.
  • it is desired to raise the arm while travelling after lifting an article with the bucket it would be impossible to attain the end of raising the arm if the arm holding pressure is raised above a certain level by the weight of the bucket.
  • the boom directional control valve is connected in tandem with the bucket directional valve on the downstream side of the latter. This makes it impossible to perform boom, arm and bucket simultaneous combined operations and swivelling, boom, arm and bucket simultaneous combined operations. Also, the arrangement whereby the boom directional control valve is connected to the travelling motor on the downstream side of the latter makes it impossible to perform travelling, boom and arm simultaneous combined operations and swivelling, travelling and boom simultaneous combined operations.
  • An object of this invention is to provide a hydraulic drive system for civil engineering and construction machinery capable of performing travelling and boom simultaneous combined operations and/or travelling and arm simultaneous combined operations independently of each other.
  • Another object is to provide a hydraulic drive system for civil engineering and construction machinery capable of performing three simultaneous combined operations including boom, arm and bucket operations and four combined operations including swing, boom, arm and bucket operations.
  • Still another object is to provide a hydraulic drive system for civil engineering and construction machinery capable of performing three simultaneous combined operations including travelling, boom and arm operations and another three simultaneous combined operations including swing, travelling and boom operations.
  • Still another object is to provide a hydraulic drive system for civil engineering and construction machinery capable of avoiding the occurrence of relief due to inertia of a swing when swing and boom simultaneous combined operations are performed, thereby enabling effective utilization of energy to be achieved for raising the boom.
  • a further object is to provide a hydraulic drive system for civil engineering and construction machinery enabling a plurality of actuators to perform simultaneous combined operations by actuating them in a variety of combinations while allowing the combined operations to be performed substantially independently of one another to a certain degree.
  • a hydraulic drive system for civil engineering and construction machinery comprising at least a first and second hydraulic fluid circuits for driving a plurality of hydraulic actuators, the 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 the 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, the plurality of actuators including at least left and right travelling actuators, a boom actuator and an arm actuator, wherein: the 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, the first boom and arm directional control valves being connected to the
  • the first valve group may further include a swing directional control valve for controlling flow of hydraulic fluid to a swing actuator, the swing directional control valve being connected to the first pump at a position upstream of the first arm and travelling 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 arm and travelling directional control valves, and the first boom directional control valve is connected to the first pump through a bypass line connected to the first circuit at a position upstream of the swing directional control valve.
  • the second valve group may include a bucket directional control valve for controlling flow of hydraulic fluid to the bucket actuator, the bucket directional control valve being connected to a bypass line connected to the second circuit at a position between the second travelling directional control valve and the second arm directional control valve.
  • the system may further comprise a third hydraulic circuit for driving a swing actuator, the 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 the first arm directional control valve is connected to the first pump through a bypass line connected to the first circuit at a position upstream of the first boom directional control valve.
  • the second valve group may further include a bucket directional control valve for controlling flow of hydraulic fluid to the bucket actuator, the bucket directional control valve being connected to a bypass line connected to the second circuit at a position between the second travelling directional control valve and the second boom directional control valve.
  • the first travelling directional control valve may be connected to the first pump through a bypass line connected to the first circuit at a position upstream of the first boom and arm directional control valves, the bypass line having flow restricting means mounted therein.
  • the first valve group further includes a swing directional control valve for controlling flow of hydraulic fluid to the swing actuator, the swing directional control valve being connected to the first pump at 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
  • the bypass line for the first travelling directional control valve may be connected to the first circuit at a position upstream of the swing directional control valve.
  • the first arm directional control valve may be connected to a bypass line connected to the first circuit at a position between the swing directional control valve and the first boom directional control valve.
  • the first arm directional control valve may be further connected to the first pump through a bypass line connected to the first circuit at a position upstream of the swing directional control valve, the bypass line having flow restricting means mounted therein.
  • a first embodiment of the hydraulic drive system in conformity with the invention is generally designated by the reference numeral 2 and comprises a first hydraulic circuit 8 including a first hydraulic pump 4 and a second hydraulic circuit 10 including a second hydraulic pump 6.
  • the pumps 4 and 6 are driven by prime movers 12 and 14 respectively which may be the same one or different ones.
  • the first hydraulic circuit 8 includes a first valve group 16 comprising a swing directional control valve 24, a first boom directional control valve 26, a first arm directional control valve 28, a first bucket directional control valve 30 and a left travelling directional control valve 32 and connected to the first hydraulic pump 4 through a main line 20.
  • the valves 24, 26 28, 30 and 32 are provided with a center bypass line 21 passing therethrough in the indicated order, the center bypass line 21 being connected at one end to the main line 20 and at the other end to a tank 36.
  • the second hydraulic circuit 10 includes a second valve group 18 comprising a right travelling directional control valve 38, a second arm directional control valve 40, a second bucket directional control valve 42 and a second boom directional control valve 44 and connected to the second hydraulic pump 6 through a main line 22.
  • the valves 38, 40, 42 and 44 are provided with a center bypass line 23 passing therethrough in the indicated order, the center bypass line 23 being connected at one end to the main line 22 and at the other end to the tank 36.
  • the swing directional control valve 24 has its inlet port connected to the center bypass line 21 in a position on the uppermost stream end thereof thereby to connect the valve 24 to the pump 4, and the first boom directional control valve 26 has its inlet port connected through a bypass line 34 to the center bypass line 21 in a position upstream of the valve 24 thereby to connect the valve 26 to the pump 4 - in parallel with the valve 24.
  • the first arm directional control valve 28, first bucket directional control valve 30 and left travelling directional control valve 32 have their inlet ports connected in the indicated order to the center bypass line 21 in a position downstream of the valve 26.
  • the valves 24 and 26 are adapted to be able to receive hydraulic fluid supply from the pump 4 by taking priority over the other valves of the group.
  • the right travelling directional control valve 38 has its inlet port connected to the center bypass line 23 in a position on the uppermost stream end of the center bypass line 23 thereby to connect the valve 38 to the pump 6.
  • the second arm directional control valve 40 has its inlet port connected to the center bypass line 23 in a position downstream of the valve 38.
  • the second bucket directional control valve 42 has its inlet port connected to the center bypass line 23 through a bypass line 46 in a position between the valves 38 and 40 thereby to connect the valve 42 in parallel with the valve 40.
  • the second boom directional control valve 44 has its inlet port connected to the center bypass line 23 in a position on the downmost stream end thereof.
  • the swing directional control valve 24 is connected to a swing motor 48.
  • the first boom directional control valve 26 and second boom directional control valve 44 are interlocked by a linkage B to operate conjointly and both connected to a boom cylinder 50.
  • the first arm directional control valve 28 and second arm directional control valve 40 are interlocked by a linkage C to operate conjointly and both connected to an arm cylinder 52.
  • the first bucket directional control valve 30 and second bucket directional control valve 42 are interlocked by a linkage D to operate conjointly and both connected to a bucket cylinder 54.
  • the left travelling directional control valve 32 is connected to a left travelling motor 56, and the right travelling directional control valve 38 is connected to a right travelling motor 58.
  • a bypass circuit 62 Connecting the second pump 6 to the left travelling directional control valve 32 is a bypass circuit 62 having a bypass line 60 having an on-off valve 64 mounted therein.
  • the on-off valve 64 which is normally in a closed position is interlocked with valves 24, 26, 28 and 30 by linkages A-D so as to be brought to an open position in response to actuation of each of the valves 24, 26, 28 and 30, which are disposed in positions upstream of the left travelling directional control valve 32 in which they are able to receive hydraulic fluid supply by taking priority over the valve 32.
  • the main lines 20 and 22 have mounted therein relief valves 66 and 68 respectively.
  • first valve group 16 since the first boom directional control valve 26 is located in an upstream position in which it is able to receive a hydraulic fluid supply by taking priority over the left travelling directional control valve 32, hydraulic fluid from the first pump 4 is all supplied to the boom cylinder 50 through the valve 26, thereby driving the boom.
  • second valve group 18 since the right travelling directional control valve 38 is located in an upstream position in which it is able to receive a hydraulic fluid supply by taking priority over the second boom directional control valve 44, hydraulic fluid from the second pump 6 is supplied to the right travelling motor 38 through the valve 38.
  • hydraulic fluid from the first pump 4 is all supplied through the first arm directional control valve 28 to the arm cylinder 52, and a hydraulic fluid from the second pump 6 is supplied to the left and right motors 56 and 58 through the left and right travelling directional valves 32 and 38 respectively.
  • the travelling operation and the arm operation can be performed independently of each other.
  • travelling and swing or bucket operations can be performed independently of each other.
  • the first boom directional control valve 26 is connected in parallel with the swing directional control valve 24 through the bypass line 34, so that hydraulic fluid from the first hydraulic pump 4 is supplied to the swing motor 48 and boom cylinder 50. Hydraulic fluid from the second hydraulic pump 6 is supplied to the boom cylinder 50 through the second boom directional control valve 44.
  • the swing having high inertia, the swing motor 48 tends to have a high working pressure when a swing acceleration operation is performed.
  • the majority of the hydraulic fluid supplied from the pump 4 is sent through the bypass line 34 to the boom cylinder 50, so that the working pressure of the swing motor 48 during acceleration operation is kept to the level of the working pressure of the boom cylinder 50.
  • the power can be effectively utilized for performing a boom operation.
  • the swing motor 48 would have its working pressure greatly raised in performing a swing acceleration operation and render the relief valve 66 operative, thereby causing a loss of power, a reduction in efficiency and an unsatisfactory upward movement of the boom.
  • the presence of the bypass line 34 makes it impossible to render the swing and boom operations fully independent of each other.
  • the relief valve 66 can be kept inoperative during swing acceleration operation and no loss of power occurs, the boom can be raised to a desired high level with a high degree of efficiency.
  • Hydraulic fluid from the first pump 4 is all supplied to the swing motor 48 by actuation of the swing directional control valve 24. Hydraulic fluid from the second pump 6 is all supplied to the arm cylinder 52 by actuation of the arm directional control valve 40.
  • the swing and arm operations can be performed independently of each other.
  • the swing and bucket operations can be performed independently of each other.
  • Hydraulic fluid from the first pump 4 is supplied to the boom cylinder 50 through the boom directional control valve 26. Since the second bucket directional control valve 42 is connected in parallel with the second arm directional control valye 40 through the bypass line 46, hydraulic fluid from the second pump 6 is supplied to the arm cylinder 52 and bucket cylinder 54 through the valves 40 and 42 respectively. This makes boom, arm and bucket operations performed simultaneously.
  • Hydraulicfluid from the first pump 4 is supplied to the swing motor 48 and boom cylinder 50 through the swing directional control valve 24 and the bypass line 34 and first boom directional control valve 26, respectively.
  • Hydraulic fluid from the second pump 6 is supplied to the arm cylinder 52 and bucket cylinder 54 through the second boom directional control valve 40 and the bypass line 46 and second bucket directional control valve 42, respectively.
  • the swing, boom, arm and bucket operations can be performed simultaneously.
  • Fig. 2- shows a second embodiment of the hydraulic drive system in conformity with the invention.
  • the hydraulic drive system is generally designated by the reference numeral 70 and comprises a first hydraulic circuit 72 including a first valve group 73 in which the first boom directional control valve 26 is connected to the center bypass line 21 in a position downstream of the swing directional control valve 24. That is, the valves 24, 26, 28, 30 and 32 are connected together in tandem in the indicated order so as to be able to receive a hydraulic fluid supply from the hydraulic pump 4 by taking priority in such an order.
  • the system 70 also comprises a second hydraulic circuit 74 including a second valve group 75 in which the second boom directional control valve 44 is, like the second bucket directional control valve 42, connected to the pump 6 through a bypass line 76 connected to the center bypass line 23 in a position between the right travelling directional control valve 38 and the second arm directional control valve 40.
  • the combined operations (1 )-(7) that have been performed in the first embodiment shown in Fig. 1 can be performed substantially in like manner except that in the combined operations of swing and boom, it is impossible to avoid the occurrence of relief due to inertia of the swing. Instead, in the second embodiment, the combined operations of swing and boom can be performed fully independently of each other without actuating the operation lever in two stages as in the first embodiment.
  • FIG. 3 A third embodiment of the hydraulic drive system in conformity with the invention will be described by referring to Fig. 3 in which the hydraulic drive system generally designated by the reference numeral 80 comprises parts similar to those shown in Fig. 1 designated by like reference characters.
  • the hydraulic drive system 80 comprises a first hydraulic circuit 2 including the first hydraulic pump 4, and second hydraulic circuit 84 including the second hydraulic pump 6.
  • the pumps 4 and 6 are driven by the prime movers 12 and 14 respectively which may be the same one or different ones.
  • the first circuit 82 includes a first valve group 83 comprising the swing directional control valve 24, first boom directional control valve 26, first arm directional control valve 28, first bucket directional control valve 30 and left travelling directional control valve 32 and connected to the pump 4 through the main line 20.
  • the valves 24, 26, 28, 30 and 32 are provided with the center bypass line 21 passing therethrough in the indicated order, the center bypass line 21 being connected at one end to the main line 20 and at the other end to the tank 36.
  • the second circuit 84 includes a second valve group 85 comprising the right directional control valve 38, second boom directional control valve 44, second bucket directional control valve 42 and second arm directional control valve 40 and connected to the pump 6 through the main line 22.
  • the valves 38, 44, 42 and 40 are provided with the center bypass line 23 passing therethrough in the indicated order, the bypass line 23 being connected at one end to the main line 22 and at the other end to the tank 36.
  • the swing directional control valve 24 has its inlet port connected to the center bypass line 21 in a position on the uppermost stream end thereof thereby to connect the valve 24 to the pump 4, and the first boom directional control valve 26 has its inlet port connected to the center bypass line 21 through a bypass line 86 in a position upstream of the valve 24 thereby to connect the valve 26 to the pump 4 in parallel with the valve 24.
  • the first arm directional control valve 28 has its inlet port connected through a bypass line 88 to the center bypass line 21 in a position between the valves 24 and 26 thereby to connect the valve 28 in parallel with the valve 26.
  • the inlet port of the first arm directional control valve 28 is also connected through a bypass line 90 to the center bypass line 21 in a position upstream of the valve 24 thereby to connect the valve 28 to the pump 4, and a restrictor 92 is mounted in the bypass line 90.
  • the first bucket directional control valve 30 has its inlet port connected to the center bypass line 21 in a position downstream of the valve 28 and to the center bypass line 21 in a position downstream of the valve 28 and to the center bypass line 21 through a bypass line 94 in a position upstream of the valve 24 thereby to connect the valve 30 to the pump 4, and a restrictor 96 is mounted in the bypass line 94.
  • the left travelling directional control valve 32 has its inlet port connected to the center bypass line 21 in a position downstream of the valve 30 and to the center bypass line 21 in a position upstream of the valve 24 through a bypass line 98 thereby to connect the valve 32 to the pump 4, and a restrictor 100 is mounted in the bypass line 98.
  • the right travelling directional control valve 38 has its inlet port connected to the center bypass line 23 in a position at the uppermost stream end thereof thereby to connect the valve 38 to the pump 6 so as to be able to receive a hydraulic fluid supply from the pump 6 by taking priority over the other valves in the group.
  • the second boom directional control valve 44 has its inlet port connected to the center bypass line 23 in a position downstream of the valve 38.
  • the second bucket directional control valve 42 has it in.tet port connected through a bypass line 102 to the center bypass line 23 in a position between the valves 38 and 44 thereby to connect the valve 42 in parallel with the valve 44.
  • the second arm directional control valve 40 has its inlet port connected to the center bypass line 23 in a position at the downmost stream end of the center bypass line 23.
  • the swing directional control valve 24 is connected to the swing motor 48.
  • the first boom directional valve 26 and second boom directional control valve 44 are interlocked by the linkage B and both connected to the boom cylinder 50.
  • the first arm directional control valve 28 and second arm directional control valve 40 are interlocked by the linkage C and both connected to the arm cylinder 52.
  • the first bucket directional control valve 30 and second bucket directional control valve 42 are interlocked by the linkage D and both connected to the bucket cylinder 54.
  • the left travelling directional control valve 32 is connected to the left travelling motor 56.
  • the right travelling directional control valve 38 is connected to the right travelling motor 58.
  • a bypass circuit 106 including a bypass line 104 connected at one end to the inlet port of the right travelling directional control valve 38 and at the other end to the inlet port of the left travelling directional control valve 30.
  • the on-off valve 64 which, although normally closed, is brought to an open position by the linkages A-D in response to actuation of each of the valves 24, 26, 28 and 30 upstream of the left travelling directional control valve 32.
  • the boom directional control valve 26 is located in an upstream position of the left travelling directional control valve 32 in the center bypass line 21 and the bypass line 98 for the valve 32 mounts the restrictor 98, the majority of hydraulic fluid from the pump 4 is supplied to the boom cylinder through the valve 26, thereby driving the boom.
  • the right travelling directional control valve 38 is located on the upstream side of the boom directional control valve 44 so as to be able to receive a hydraulic fluid supply by taking priority thereover, hydraulic fluid from the pump 6 is supplied to the right travelling motor 58 through the valve 38.
  • hydraulic fluid from the pump 6 is also supplied through the bypass line 104 and the left travelling directional control valve 32 to the left travelling motor 56.
  • the left and right travelling motors 56 and 58 are essentially driven by hydraulic fluid supply from the pump 6.
  • a small portion of hydraulic fluid from the hydraulic pump 4 flows through the bypass line 98 and restrictor 100 to the left directional control valve 32.
  • bypass line 98 and restrictor 100 function to prevent all the amount of hydraulic fluid from the pump 4 from being cut off by the valve 26, and therefore it is posible to eliminate large fluctuations in travelling speed and reduce a shock upon actuation of the valve 26, and also it is possible to minimize reduction in travelling speed after the actuation of the valve 26.
  • the majority of hydraulic fluid from the pump 4 is supplied to the arm cylinder 52 through the arm directional control valve 28, and hydraulic fluid from the pump 6 is supplied through the left and right travelling directional control valve 32 and 38 to the left and right motors 56 and 58 respectively.
  • the provision of the restrictor 100 to the bypass line 98 enables the travelling and arm operations to be performed highly independently of each other. Also, the provision of the bypass line 98 and restrictor 100 can prevent occurrence of sudden fluctuations in the travelling speed and thus reduce a shock and moreover minimize reduction in travelling speed when the valve 28 is actuated during travelling operation.
  • the travelling and swing or bucket operations can be performed highly independently of each other and a shock and a reduction in travelling speed can be minimized when a swing or bucket operation is performed during travelling operation.
  • the provision of the restrictor 92 to the bypass line 90 permits the majority of hydraulic fluid from the pump 4 to be supplied through the swing directional control valve 24 to the swing motor 48. Hydraulic fluid from the pump 6 is supplied through the second arm directional control valve 40 to the arm cylinder 52. By restricting the flow of hydraulic fluid through the restrictor 92 in such a manner that a pressure high enough to drive the swing can be obtained, it is possible to permit the swing and arm operations to be performed highly independently of each other.
  • bypass line 90 and restrictor 92 allows hydraulic fluid from the pump 4 to flow in part, when inertia of the swing raises the working pressure of the swing motor 48 during swing acceleration, to the arm cylinder 52 through the bypass line 90 and restrictor 92.
  • the two operations need be performed completely independently of each other, one has only to actuate the arm operation lever in two stages as in the swing and boom combined operations in such a manner that the second arm directional control valve 40 is only actuated in the first stage while the two arm directional control valves 28 and 40 are actuated in the second stage.
  • the swing and arm operations can be performed completely independently of each other.
  • the swing operation is performed simultaneously as the bucket operation, the two operations can be performed in the same manner as the swing and arm combined operations.
  • the majority of hydraulic fluid from the pump 4 is supplied to the boom cylinder 50 through the first boom directional control valve 26 and to the arm cylinder 52 through the bypass line 88 and first arm directional control valve 28, and a small portion of the hydraulic fluid is supplied to the bucket cylinder through the bypass line 94 and first bucket directional control valve 30.
  • Hydraulic fluid from the pump 6 is supplied to the boom cylinder 50 through the second boom directional control valve 44 and to the bucket cylinder 54 through the bypass line 102 and second bucket directional control valve 42.
  • Hydraulic fluid from the pump 4 is supplied to the swing motor 48 through the swing directional control valve 24, to the boom cylinder 50 through the bypass line 86 and first boom directional control valve 26, to the arm cylinder 52 through the bypass line 90 and first arm directional control valve 28, and to the bucket cylinder 54 through the bypass line 94 and first bucket directional control valve 30.
  • Hydraulic fluid from the pump 6 is supplied to the boom cylinder 50 through the second boom directional control valve 44, and to the bucket cylinder 54 through the bypass line 102 and second bucket directional control valve 42.
  • bypass line 88 enables travelling, boom, and arm combined operations to be performed.
  • the provision of the bypass lines 86 and 92 enables swing, travelling and boom combined operations and swing, travelling and arm combined operations respectively to be performed.
  • the provision of the bypass line 104 enables left side tavelling to be performed while performing swing operation.
  • the combination of the bypass line 98 and throttle 100 has the effect of avoiding the occurrence of relief during swing acceleration when performing the swing and travelling combined operations.
  • Fig. 4 shows a fourth embodiment of the hydraulic drive system in conformity with the invention, in which parts similar to those shown in Figs. 1 and 3 are designated by like reference characters.
  • the hydraulic drive system is generally designated by the reference numeral 110 and comprises a first hydraulic circuit 112 and a second hydraulic circuit 114.
  • the first circuit 112 comprises a first valve groove 116 in which the arrangement of the elements is substantially similar to that of the embodiment shown in Fig. 3 except that the bucket directional control valve of low importance is not mounted, that the arm directional control valve 28 has its inlet port connected to the center bypass line 21, not a bypass line, in a position downstream of the bucket directional control valve 26 by attaching importance to the operation of the latter, and that no bypass circuit is mounted between the left travelling directional control valve 32 and second pump 6.
  • the second circuit 114 comprises a second valve group 118 in which the arrangement of the elements is substantially similar to that of the embodiment shown in Fig. 3.
  • the system 110 further comprises an auxiliary left travelling directional control valve 120 interlocked with the left travelling directional control valve 32 but constituting a separate entity therefrom, and a bypass circuit 124 including a bypass line 122 connecting the valve 120 to the second pump 6.
  • the on-off valve 64 mounted in the bypass circuit 124 is interlocked with the valves 24, 26 and 28 upstream of the left travelling directional control valve 32 in the center bypass line 21 by the linkages A, B and C, and is brought to an open position in response to actuation of each of the valves 24, 26 and 28.
  • the auxiliary left travelling directional control valve 120 may be in the form of a six port valve.
  • the arm directional control valve 28 has its inlet port connected to the center bypass line 21 in a position downstream of the boom directional control valve 26 as aforesaid. Owing to this arrangement, hydraulic fluid flows into the arm cylinder 52 through the throttle 92 and thus the operation of the arm may be slightly reduced in speed in combined operations involving the boom and arm. In other respects, the performance of the system is substantially similar to that of the embodiment shown in Fig. 3.
  • Fig. 5 shows a fifth embodiment of the hydraulic drive system in conformity with the invention, in which parts similar to those shown in Figs. 1 and 3 are designated by the reference numeral 130 and comprises a first hydraulic circuit 132 and a second hydraulic circuit 134 including the first and second hydraulic pumps 4 and 6 respectively.
  • the first hydraulic circuit 132 further includes a first valve group 136 in which the arrangement of the elements is substantially similar to that of the embodiment shown in Fig. 3 except that no swing directional control valve is mounted and that no restrictor is mounted in the bypass line 94 for the bucket directional control valve 30.
  • the second hydraulic circuit 132 includes a second valve group 138 in which the arrangement of the elements is substantially similar to that of the embodiment shown in Fig. 3.
  • the on-off valve 64 is interlocked with the valves 26, 28 and 30 upstream of the left travelling directional control valve 32 in the center bypass line 21 by the linkages B, C and D, and is brought to an open position in response to actuation of each of the valves 26, 28 and 30.
  • the hydraulic drive system 130 shown in Fig. 5 further comprises a third hydraulic circuit 144 including a third hydraulic pump 142, in which the swing directional control valve 24 is connected to receive a hydraulic fluid supply from the pump 142 through a main line 146.
  • the pump 142 is driven by a prime mover 148 which may be the same one as or different ones from the prime movers 12 and 14.
  • a relief valve 150 is mounted in the main line 146.
  • valves 24-32 and 38-44 are shown as being manually operated.
  • the invention is not limited to this specific type of valves and valves of the hydraulic type controlled by pilot pressure signals, valves of the electric type controlled by electrical signals, valves of the mechanical type controlled by mechanical displacement signals and any other suitable valves of the known type may be used.
  • the bypass circuits 62, 106, 124 and 140 mount the on-off valve 64. However, this is not essential and the on-off valves 64 may be dispensed with and the bypass lines 60, 104 and 122 may be kept open at all times. When this is the case, the left and right travelling motors 56 and 58 would be communicated with each other during travelling operation with no other operations being performed. Thus if a difference is produced in working pressure between them, a larger quantity of hydraulic pressure fluid would flow to the motor of lower working pressure, thereby preventing the left and right travelling operations being performed independently of each other.
  • the on-off valve 64, second boom directional control valve 44, second arm directional control valve 40 and second bucket directional control valve 42 have been described as being interlocked by the linkages A, B, C and D. However, the invention is not limited to this specific arrangement of the valves and the valves may be actuated independently by separate operation levers.
  • the bucket directional control valve 42 of the second valve groups 18, 75, 85 and 138 may be dispensed with because this valve is low in importance.
  • either the boom directional control valve 44 or the arm directional control valve 40 of the second valve groups 18, 75, 85, 118 and 138 may be dispensed with.
  • the bucket directional control valve 42 of the second valve group may be located upsteam of the right travelling directional control valve 49 in the center bypass line when there is no need to perform combined operations including bucket and travelling operations.
  • auxiliary left travelling directional control valve may be provided in addition to the left travelling directional control valve 32 as shown in Fig. 4 and a bypass circuit may connect such auxiliary left travelling directional control valve to the second pump.
  • Fig. 1 may be modified in a manner to have a third hydraulic circuit exclusively for the swing directional control valve as is the case with the embodiment shown in Fig. 5.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • Operation Control Of Excavators (AREA)
  • Fluid-Pressure Circuits (AREA)

Claims (20)

1. Système de commande hydraulique pour engins de travaux publics et de construction comportant au moins un premier (8) et un deuxième (10) circuit hydraulique pour entraîner une pluralité de mécanismes hydrauliques d'actionnement, ledit premier circuit comportant une première pompe hydraulique (4), et un premier groupe (16) de distributeurs possédant plusieurs distributeurs pour commander le passage de fluide hydraulique depuis la première pompe jusqu'aux mécanismes d'actionnement coopérant avec elle, et ledit deuxième circuit comportant une deuxième pompe hydraulique (6), et un deuxième groupe (18) de distributeurs possédant plusieurs distributeurs pour commander le passage de fluide hydraulique depuis la deuxième pompe jusqu'aux mécanismes d'actionnement coopérant avec elle, ladite pluralité de mécanismes d'actionnement comprenant au moins des dispositifs gauche et droit (56, 58) de commande de déplacement, un dispositif (50) de commande de flèche et un dispositif (52) de commande de bras, caractérisé en ce que:
ledit premier groupe (16) de distributeurs comporte un premier distributeur (32) de commande de déplacement pour commander le passage de fluide hydraulique jusqu'à l'un (56) des dispositifs de commande de déplacement gauche et droit, un premier distributeur (56) de commande de flèche pour commander l'écoulement du fluide hydraulique jusqu'au dispositif (50) de commande de flèche, et un premier distributeur (28) de commande de bras pour commander le passage du fluide hydraulique jusqu'au dispositif (52) de commande de bras, lesdits premiers distributeurs de commande de flèche et de bras étant reliés à la première pompe (4) en un point en amont du premier distributeur (32) de commande de déplacement sur le premier circuit de façon à pouvoir recevoir une alimentation en fluide hydraulique depuis la première pompe en pre- mant la priorité sur le premier distributeur de commande de déplacement;
ledit deuxième groupe (18) de soupapes comporte un deuxième distributeur (38) de commande de déplacement pour commander le passage de fluide hydraulique jusqu'à l'autre (58) des dispositifs gauche et droit de commande de déplacement et un deuxième distributeur (44) de commande de flèche pour commander le passage de fluide hydraulique jusqu'au dispositif (50) de commande de flèche et/ou un deuxième distributeur (40) de commande de bras pour commander le passage de fluide hydraulique jusqu'au dispositif (52) de commande de bras, ledit deuxième distributeur de commande de déplacement étant relié à la deuxième pompe (6) en un point en amont des deuxièmes distributeurs de commande de flèche et/ou de bras sur la deuxième circuit de façon à pouvoir recevoir une alimentation en fluide hydraulique depuis la deuxième pompe en prenant la priorité sur les deuxièmes distributeurs de commande de flèche et/ou de bras; et
le système comporte en outre un circuit de dérivation (62) comportant une conduite de dérivation (60) s'étendant entre la deuxième pompe et le premier dispositif (56) de commande de déplacement, ledit circuit de dérivation servant à permettre à une alimentation en fluide hydraulique issue de la deuxième pompe d'être reçue par le premier dispositif de commande de déplacement lorsqu'est actionné au moins un des distributeurs du premier groupe (16) de distributeurs en amont du premier distributeur (32) de commande de déplacement qui comprennent les distributeurs de commande de flèche et de bras.
2. Système de commande hydraulique selon la revendication 1, dans lequel ledit circuit de dérivation comporte une vanne de marche-arrêt (64) montée dans ladite conduite de dérivation, ladite vanne de marche-arrêt se trouvant normalement placée en position fermée et étant conçue pour être amenée en position ouverte au moment de l'actionnement d'au moins un des distributeurs dudit premier groupe (16) de distributeurs en amont dudit premier distributeur (32) de commande de déplacement.
3. Système de commande hydraulique selon la revendication 1 ou 2, dans lequel ladite conduite de dérivation (60) relie ladite deuxième pompe audit premier distributeur (32) de commande de déplacement.
4. Système de commande hydraulique selon la revendication 1 ou 2, dans lequel dedit circuit de dérivation (124) comporte un troisième distributeur (120) de commande de déplacement monté sur ladite conduite de dérivation (122) et asservi audit premier distributeur (32) de commande de déplacement.
5. Système de commande hydraulique selon la revendication 1, dans lequel lesdits deuxièmes distributeurs (44, 40) de commande de flèche et/ ou de bras sont asservis auxdits premiers distributeurs (26, 28) de commande de flèche et de bras.
6. Système de commande hydraulique selon la revendication 1, dans lequel ladite pluralité de mécanismes d'actionnement comprend en outre un dispositif (48) de commande d'oscillation, dans lequel ledit premier groupe (16) de soupapes comporte en outre un distributeur (24) de commande d'oscillation pour commander le passage de fluide hydraulique jusqu'audit dispositif de commande d'oscillation, ledit distributeur de commande d'oscillation étant relié à ladite première pompe (4) en un point en amont desdits premiers distributeurs de commande de bras et de déplacement de façon à pouvoir recevoir une alimentation en fluide hydraulique depuis la première pompe en prenant la priorité sur les premiers distributeurs de commande de bras et de déplacement, et ledit premier distributeur (26) de commande de flèche étant relié à la première pompe via une deuxième conduite de dérivation (34) montée sur le premier circuit en un point en amont dudit distributeur de commande d'oscillation.
7. Système de commande hydraulique selon la revendication 1 ou 6, dans lequel ladite pluralité de mécanismes d'actionnement comprend en outre un dispositif (54) de commande de benne, dans lequel ledit deuxième groupe (18) de distributeurs comporte en outre un distributeur (42) de commande de benne pour commander le passage de fluide hydraulique jusqu'au dispositif de commande de benne, ledit distributeur de commande de benne étant relié à une troisième conduite de dérivation (46) montée sur la deuxième circuit en un point entre le deuxième distributeur (38) de commande de déplacement et le deuxième distributeur (40) de commande de bras.
8. Système de commande hydraulique selon la revendication 1, dans lequel ladite pluralité de mécanismes d'actionnement comprend en outre un dispositif (48) de commande de rotation et un dispositif (54) de commande de benne, dans lequel ledit premier groupe de distributeurs comporte en outre un distributeur (24) de commande de rotation pour commander le passage de fluide hydraulique jusqu'audit dispositif de commande de rotation, ledit distributeur de commande de rotation étant relié à la première pompe (4) en un point en amont desdits premiers distributeurs (26, 28) de commande de flèche et de bras sur le premier circuit de façon à pouvoir recevoir une alimentation en fluide hydraulique depuis la première pompe en prenant la priorité sur les premiers distributeurs de commande de flèche et de bras, et ledit deuxième groupe (18) de distributeurs comporte en outre un distributeur (42) de commande de benne pour commander le passage de fluide hydraulique jusqu'audit dispositif de commande de benne, lesdits deuxièmes distributeurs (44, 42) de commande de flèche et de benne étant reliés respectivement à des quatrième et cinquième conduites de dérivation (46, 76), qui sont montées sur le deuxième circuit en un point entre le deuxième distributeur (38) de commande de déplacement et le deuxième distributeur (40) de commande de bras.
9. Système de commande hydraulique selon la revendication 1, dans lequel ladite pluralité de mécanismes d'actionnement comprend en outre un dispositif (48) de commande de rotation, dans lequel ledit système comporte en outre un troisième circuit hydraulique (144) pour actionner ledit dispositif de commande de rotation, ledit troisième circuit comportant une troisième pompe hydraulique (142) et un distributeur (24) de commande de rotation pour commander le passage de fluide hydraulique jusqu'audit dispositif de commande de rotation depuis ladite troi- siéme pompe, et ledit premier distributeur (28) de commande de bras est relié à la première pompe par une sixième conduite de dérivation (88) montée sur le premier circuit en un point en amont du premier distributeur (26) de commande de flèche.
10. Système de commande hydraulique selon la revendication 9, dans lequel ladite pluralité de mécanismes d'acionnement comprend en outre un dispositif (54) de commande de benne, dans lequel ledit deuxième groupe de distributeurs comporte en outre un distributeur (42) de commande de benne pour commander le passage de fluide hydraulique jusqu'audit dispositif de commande de benne, ledit distributeur de commande de benne étant relié à une septième conduite de dérivation (102) montée sur le deuxième circuit en un point entre le deuxième distributeur (38) de commande de déplacement et le deuxième distributeur de commande de flèche.
11. Système de commande hydraulique selon la revendication 1, dans lequel ledit premier distributeur (32) de commande de déplacement est relié à la première pompe (4) par une huitième conduite de dérivation (98) montée sur le premier circuit en un point en amont des premiers distributeurs (26, 28) de commande de flèche et de bras, un moyen (100) de réduction de début étant monté dans ladite huitième conduite de dérivation.
12. Système de commande hydraulique selon la revendication 11, dans lequel ladite multiplicité de mécanismes d'actionnement comprend en outre un dispositif (48) de commande de rotation, dans lequel ledit premier groupe de distributeurs comporte en outre un distributeur (24) de commande de rotation pour commander le passage de fluide hydraulique jusqu'audit dispositif de commande de rotation, ledit distributeur de commande de rotation étant relié à la première pompe (4) en un point en amont du premier distributeur (32) de commande de déplacement sur le premier circuit de façon à pouvoir recevoir une alimentation en fluide hydraulique depuis la première pompe en prenant la priorité sur le premier distributeur de commande de déplacement, ladite huitième conduite de dérivation (98) étant montée sur le premier circuit en un point en amont du distributeur de commande de rotation.
13. Système de commande hydraulique selon la revendication 12, dans lequel ledit premier distributeur (26) de commande de flèche est relié à la première pompe (4) par une neuvième conduite de dérivation (86) montée sur le premier circuit en un point en amont du distributeur (24) de commande de rotation.
14. Système de commande hydraulique selon la revendication 12, dans lequel ledit premier distributeur (28) de commande de bras est relié à une dixième conduite de dérivation (88) montée sur le premier circuit en un point entre le distributeur (24) de commande de rotation et le premier distributeur (26) de commande de flèche.
15. Système de commande hydraulique selon la revendication 13, dans lequel ledit premier distributeur (28) de commande de bras est relié à une onzième conduite de dérivation montée sur le premier circuit en un point entre le distributeur (24) de commande de rotation et le premier distributeur (24) de commande de flèche.
16. Système de commande hydraulique selon la revendication 12, dans lequel ledit premier distributeur (28) de commande de bras est relié à la première pompe par une douzième conduite de dérivation (90) montée sur le premier circuit en un point en amont du distributeur (24) de commande de rotation, un moyen (92) de réduction de débit étant monté dans ladite douzième conduite de dérivation.
17. Système de commande hydraulique selon la revendication 13, dans lequel ledit premier distributeur (28) de commande de bras est relié à la première pompe par une treizième conduite de dérivation montée sur le premier circuit en un point en amont du distributeur (24) de commande de rotation, un moyen de réduction de débit étant monté dans ladite treizième conduite de dérivation.
18. Système de commande hydraulique selon l'une quelconque des revendications 14 à 17, dans lequel ladite pluralité de mécanismes d'actionnement comprend en outre un dispositif (54) de commande de benne, dans lequel ledit deuxième groupe de distributeurs comporte en outre un distributeur (42) de commande de benne pour commander le passage de fluide hydraulique jusqu'audit dispositif de commande de benne, ledit distributeur de commande de benne étant relié à une quatorzième conduite de dérivation (102) montée sur le deuxième circuit en un point entre le deuxième distributeur (38) de commande de déplacement et le deuxième distributeur (44) de commande de flèche.
19. Système de commande hydraulique selon la revendication 11, dans lequel ladite pluralité de mécanisme d'actionnement comprend en outre un dispositif (48) de commande de rotation, dans lequel ledit système comporte en outre un troisième circuit (144) de fluide hydraulique pour actionner ledit dispositif de commande de rotation, ledit troisième circuit comportant une troisième pompe hydraulique (142) et un distributeur (24) de commande de rotation pour commander le passage de fluide hydraulique depuis la troisième pompe jusqu'au dispositif de commande de rotation, et ledit premier distributeur (28) de commande de bras est relié à la première pompe par une quinzième conduite de dérivation (88) montée sur le premier circuit en un point en amont du premier distributeur (26) de commande de flèche.
20. Système de commande hydraulique selon la revendication 19, dans lequel ladite pluralité de mécanismes d'actionnement comprend en outre un dispositif (54) de commande de benne, dans lequel ledit deuxième groupe de soupapes comporte en outre un distributeur (42) de commande de benne pour commander le passage de fluide hydraulique jusqu'audit dispositif de commande de benne, ledit distributeur de commande de benne étant relié à une seizième conduite de dérivation (102) monteé sur le deuxième circuit en un point entre le deuxième distributeur (38) de commande de déplacement et le deuxième distributeur (44) de commande de flèche.
EP19820101590 1981-03-03 1982-03-02 Système d'entraînement hydrostatique pour machines de travaux publics Expired EP0059471B1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP56029320A JPS57146842A (en) 1981-03-03 1981-03-03 Oil-pressure circuit for civil and construction machinery
JP29320/81 1981-03-03
JP87553/81 1981-06-09
JP56087553A JPS57205636A (en) 1981-06-09 1981-06-09 Oil-pressure circuit for oil-pressure working machine
JP57028556A JPS58146632A (ja) 1982-02-24 1982-02-24 土木建設機械の油圧駆動システム
JP28556/82 1982-02-24

Publications (3)

Publication Number Publication Date
EP0059471A2 EP0059471A2 (fr) 1982-09-08
EP0059471A3 EP0059471A3 (en) 1983-09-21
EP0059471B1 true EP0059471B1 (fr) 1986-05-28

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EP19820101590 Expired EP0059471B1 (fr) 1981-03-03 1982-03-02 Système d'entraînement hydrostatique pour machines de travaux publics

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KR (1) KR870000505B1 (fr)
DE (1) DE3271311D1 (fr)

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JPS58146630A (ja) * 1982-02-25 1983-09-01 Hitachi Constr Mach Co Ltd 油圧作業機械の油圧回路
EP0235545B1 (fr) * 1986-01-25 1990-09-12 Hitachi Construction Machinery Co., Ltd. Système hydraulique d'entraînement
US5115835A (en) * 1990-01-26 1992-05-26 Zexel Corporation Stacked type hydraulic control valve system
JP2702646B2 (ja) * 1992-08-07 1998-01-21 株式会社クボタ バックホウ装置の油圧回路構造
JPH0776859A (ja) * 1993-09-09 1995-03-20 Hitachi Constr Mach Co Ltd 建設機械の油圧駆動装置
JP2892939B2 (ja) * 1994-06-28 1999-05-17 日立建機株式会社 油圧掘削機の油圧回路装置
AU720849B2 (en) * 1996-03-28 2000-06-15 Clark Equipment Company Multifunction valve stack
JP3497947B2 (ja) * 1996-06-11 2004-02-16 日立建機株式会社 油圧駆動装置
RU2403348C2 (ru) * 2005-10-14 2010-11-10 Вольво Констракшн Эквипмент Аб Рабочая машина

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DE2148502B2 (de) * 1971-09-29 1978-11-02 G.L. Rexroth Gmbh, 8770 Lohr Ein- oder mehrkreisiges Hydrauliksystem
US4030623A (en) * 1971-12-13 1977-06-21 Caterpillar Tractor Co. Hydraulic circuitry for an excavator
DE2440251A1 (de) * 1974-08-22 1976-03-04 Linde Ag Schaltung fuer zwei kreislaeufe zur vereinigung der foerderstroeme beider pumpen
US4210061A (en) * 1976-12-02 1980-07-01 Caterpillar Tractor Co. Three-circuit fluid system having controlled fluid combining
US4112821A (en) * 1976-12-03 1978-09-12 Caterpillar Tractor Co. Fluid control system for multiple circuited work elements
JPS5847109Y2 (ja) * 1977-10-31 1983-10-27 株式会社クボタ バックホウ兼ド−ザ作業車の回路構造
US4207740A (en) * 1979-06-12 1980-06-17 Akermans Verkstad Ab Valve blocks, in particular for hydraulic excavators

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Publication number Publication date
KR870000505B1 (ko) 1987-03-12
DE3271311D1 (en) 1986-07-03
EP0059471A3 (en) 1983-09-21
KR830009399A (ko) 1983-12-21
EP0059471A2 (fr) 1982-09-08

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