EP0620371A1 - Système hydraulique pour alimentation de fonctions hydrauliques ouvertes ou fermées - Google Patents

Système hydraulique pour alimentation de fonctions hydrauliques ouvertes ou fermées Download PDF

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Publication number
EP0620371A1
EP0620371A1 EP94104713A EP94104713A EP0620371A1 EP 0620371 A1 EP0620371 A1 EP 0620371A1 EP 94104713 A EP94104713 A EP 94104713A EP 94104713 A EP94104713 A EP 94104713A EP 0620371 A1 EP0620371 A1 EP 0620371A1
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EP
European Patent Office
Prior art keywords
hydraulic
valve
pressure
feed line
control
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Granted
Application number
EP94104713A
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German (de)
English (en)
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EP0620371B1 (fr
Inventor
Manfred Becker
Hilmar Ortlepp
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Deere and Co
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Deere and Co
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    • 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
    • F15B11/055—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 by adjusting the pump output or bypass
    • 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
    • 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
    • E02F9/2232—Control of flow rate; Load sensing arrangements using one or more variable displacement pumps
    • 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
    • E02F9/2285—Pilot-operated systems
    • 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
    • E02F9/2296—Systems with a variable displacement pump
    • 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
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30505—Non-return valves, i.e. check 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
    • F15B2211/30—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
    • F15B2211/315—Directional control characterised by the connections of the valve or valves in the circuit
    • F15B2211/31523—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source and an output member
    • F15B2211/31529—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source and an output member having a single pressure source and a single 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
    • F15B2211/30—Directional control
    • F15B2211/315—Directional control characterised by the connections of the valve or valves in the circuit
    • F15B2211/31552—Directional control characterised by the connections of the valve or valves in the circuit being connected to an output member and a return line
    • F15B2211/31558—Directional control characterised by the connections of the valve or valves in the circuit being connected to an output member and a return line having a single 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
    • F15B2211/30—Directional control
    • F15B2211/315—Directional control characterised by the connections of the valve or valves in the circuit
    • F15B2211/3157—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source, an output member and a return line
    • F15B2211/31576—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source, an output member and a return line having a single pressure source and a single 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
    • F15B2211/30—Directional control
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/327—Directional control characterised by the type of actuation electrically or electronically
    • 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
    • F15B2211/329—Directional control characterised by the type of actuation actuated by fluid 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
    • F15B2211/40576—Assemblies of multiple valves
    • F15B2211/40584—Assemblies of multiple valves the flow control means arranged in parallel with a check 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
    • F15B2211/40—Flow control
    • F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
    • F15B2211/41509—Flow control characterised by the connections of the flow control means in the circuit being connected to a pressure source and a directional control 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
    • F15B2211/40—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
    • F15B2211/40—Flow control
    • F15B2211/46—Control of flow in the return line, i.e. meter-out 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
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/635—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements
    • F15B2211/6355—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements having valve means

Definitions

  • the invention relates to a hydraulic system with an adjustable hydraulic pump, the output pressure of which can be controlled as a function of a pressure present at a load signaling connection, a reservoir, at least one hydraulic function with a feed line and a valve arrangement arranged between the hydraulic pump, reservoir and hydraulic function.
  • Modern agricultural tractors today have constant pressure hydraulic systems in which control valves block the flow of liquid from the pump in their neutral position (closed or closed center system). Furthermore, in these systems the hydraulic fluid delivery quantity can be compensated in such a way that only the required fluid quantity is supplied by the pump (power-on-demand).
  • the core of such systems is the so-called load signaling line from the consumer to the load signaling connection of the hydraulic pump, with the aid of which the hydraulic pump adjusts its output pressure at any time as a function of the pressure present at the load signaling connection and thus only provides the necessary requirements. In this way, energy can be saved to a considerable extent.
  • control units are usually designed as constant flow valves that are open in their central position (open center design) or as constant pressure valves that are closed in their central position (closed center design), they do not always have the necessary load signaling connection. If, for example, a control valve of the tractor hydraulic system described above is used to control the fluid flow to the hydraulic functions of an implement with constant pressure request, the hydraulic pump of the tractor must be operated continuously at maximum operating pressure. This results in higher power losses than necessary. This also increases fuel consumption and the result is an additional heat load.
  • valve kits which are usually supplied for attachments with constant pressure hydraulic systems, in order to be able to connect them to tractors with constant current hydraulic systems.
  • an electrical control signal from the attachment is used to control a relief valve of the valve kit.
  • the operator In this mode of operation, the operator must carefully adjust the tractor valve that supplies the hydraulic fluid to keep power losses to a minimum. Even with such an attitude, there is still an uninterrupted flow of liquid, when the implement function is not operated, which results in undesirable loss of performance.
  • the object on which the invention is based is seen in providing a solution for a hydraulic system of the type mentioned at the outset by means of which the problems described can be overcome.
  • the hydraulic system should enable a simple and effective interface between different attachment functions and a load-reporting hydraulic system with a compensated amount of liquid, in which the hydraulic pump pressure is limited to the required level.
  • This interface is not intended to require extensive hydraulic installation work or valve modifications in order to obtain a load reporting signal when using different implement functions, by means of which the hydraulic pump can be controlled.
  • a valve arrangement is provided between the hydraulic function and the load signaling connection of the hydraulic pump, which in a rest position closes a passage between the hydraulic function and the load signaling connection and opens in an operating position.
  • a valve of the valve assembly includes a spool which is urged into its rest position by a spring. Furthermore, the slide is exposed to a differential pressure and opens the valve when a differential pressure value corresponding to the spring force is exceeded. Which pressures are used to form the differential pressure depends on the hydraulic function used.
  • a hydraulic system of this type can generate a load signal for any hydraulic functions by means of which the hydraulic pump can be controlled. It provides a simple and effective interface between the hydraulic pump and hydraulic function through which the hydraulic pump outlet pressure can be limited to the required level. No extensive hydraulic installations or valve modifications are required to obtain a usable load signal despite a change between different hydraulic functions.
  • the hydraulic function is designed as an open constant-current hydraulic system, in which the associated control valve drains the hydraulic fluid into the reservoir in its neutral position (open-center design), the spring-loaded side of the control spool with the reservoir and its other side with the hydraulic function leading supply line connected. If the control valve of the hydraulic function is in its neutral position, the hydraulic fluid can flow freely from the supply line into the reservoir. Both sides of the control spool to the reservoir are relieved of pressure, so that the control spool blocks the passage of the valve (between the feed line and the load signaling connection) due to the spring force.
  • the load signaling connection is preferably connected to the reservoir via a throttle point, so that the pressure at the load signaling connection can gradually decrease even when the valve is closed.
  • the output pressure of the hydraulic pump is regulated down to the standby pressure.
  • the pump outlet is preferably connected to the feed line by a channel containing an orifice, through which a permanent control current is maintained. As a result of this control current, the pressure in the supply line separated from the storage container rises to the pump outlet pressure.
  • a check valve is preferably provided in the feed line, which only allows liquid flow from the valve to the hydraulic function, but prevents backflow.
  • This check valve is expediently bridged by a throttled channel, in order to allow a gradual pressure reduction in the supply line even when the check valve is closed and to apply the pressure of the hydraulic function to the load signaling connection.
  • the hydraulic function is designed as a constant-pressure hydraulic system that is closed in its central position and in which the associated control valve blocks the supply line in its neutral position (closed-center design), the spring-loaded side of the control spool with the supply line leading to the hydraulic function and the other side of the Control spool connected to the pump outlet.
  • the feed line is preferably connected to the pump outlet via a channel containing an orifice. If the control valve of the hydraulic function is in its neutral position, the supply line is blocked. A gradual pressure compensation takes place via the channel, so that the output pressure of the hydraulic pump is present on both sides of the control slide and the control slide assumes its closed position due to the spring force. This disconnects the load detection connection from the supply line.
  • the load signaling connection is preferably connected to the reservoir via a throttle point, so that the pressure at the load signaling connection can gradually decrease even when the valve is closed.
  • the output pressure of the hydraulic pump is regulated down to the standby pressure.
  • a changeover valve is preferably provided, by means of which either the higher of the two pressures of the pump outlet or the feed line can be applied to the side of the control slide opposite the spring. If the pressure in the supply line is higher than the pump pressure due to a load in the hydraulic function, this is reported via the shuttle valve to the second side of the control spool opposite the spring. The spool moves against the force of the spring and on its first side prevailing lower pressure in the open position of the valve, so that the pump outlet pressure is present at the load signaling connection and the pump regulates. As soon as the pump pressure exceeds the pressure in the supply line, the shuttle valve switches back to the pump outlet pressure.
  • a check valve is preferably provided in the feed line, which prevents liquid backflow from the hydraulic function to the valve.
  • the check valve serves to secure a load on the hydraulic function and avoids an initial pressure drop in the hydraulic function when the control valve is opened against a load pressure.
  • the check valve is expediently bridged by a throttled channel so that, in the event that the control valve is closed against a high load pressure and therefore the check valve is also blocked, a gradual pressure reduction in the supply line is possible and the load signaling connection is pressurized with the pressure of the hydraulic function.
  • the valve preferably controls a second passage through which the pump outlet can be connected to the supply line.
  • This passage which serves to supply the hydraulic function with hydraulic fluid and pressure, is closed or opened at the same time as the connection between the feed line and the load signaling connection.
  • This passage expediently contains an adjustable throttle point, which can be formed by an adjustable rotary slide valve. With the valve open, this enables current control of the hydraulic fluid flowing from the hydraulic pump to the hydraulic function while maintaining the advantages of the load reporting system according to the invention. Furthermore, in particular when using a hydraulic function with the control valve closed in its central position, the pressure drop generated above the throttle point can serve to stabilize the system.
  • FIG. 1 essentially shows a hydraulic pump 10, a control valve 12 with a downstream hydraulic cylinder 14 and a valve arrangement 16 arranged between the hydraulic pump 10 and the control valve 12.
  • the hydraulic pump 10 is a hydraulic pump of a tractor, not shown, which is designed as a variable displacement pump and the output pressure of which is controlled as a function of a pressure present at its load signaling connection 18.
  • the pump outlet pressure is, for example, always 30 bar above the load signaling pressure, provided the system pressure of 200 bar has not yet been reached.
  • the load signaling connection 18 is connected to a storage container 22 via a throttle point 20.
  • the load reporting pressure can slowly decrease via this throttle point 20. If there is no load signal pressure, the hydraulic pump 10 regulates and releases, for example, a standby pressure of 30 bar.
  • the valve arrangement 16 can be designed as a valve block with hydraulic connections that can be fixedly mounted on the tractor.
  • the control valve 12 and the hydraulic cylinder 14, however, can be components of an attachment, not shown, which can be optionally attached to the tractor.
  • the inputs of the control valve 12 are via flexible lines and not shown Quick fasteners connected to corresponding hydraulic connections of the valve block.
  • the control valve 12 of FIG. 1 is a 4/3-way valve, one input of which is connected to the outlet of the valve arrangement 16 and the other input of which is connected to the reservoir 22. In the central neutral position of the control valve 12, its two inputs are connected to one another, so that a constant current hydraulic circuit (closed center circuit) is formed.
  • the two cylinder spaces of the hydraulic cylinder 14 can optionally be connected to the outlet pressure of the valve arrangement 16.
  • valve arrangement 16 The heart of the valve arrangement 16 is a valve 24, through which two passages can be blocked or opened. Although these two valve functions can in principle also be implemented by using two separate valves, the use of only one control slide 26 permits a simple and compact structure.
  • a first input 1 of the valve 24 is connected to the pump outlet via an adjustable throttle point 28 which is designed as a rotary slide valve and which serves for current control, while a second input 2 of the valve 24 is connected to the load-signaling connection 18 of the hydraulic pump 10.
  • the two outputs 3 and 4 of valve 24 corresponding to inputs 1 and 2 are connected to one another. They are connected together via a check valve 30 and a throttle point 32 arranged parallel to this to a feed line 34 which connects the valve arrangement 16 to the control valve 12. Furthermore, the outputs 3 and 4 are connected to the pump output via a channel 36, which contains an orifice 38.
  • the control slide 26 of the valve 24 is loaded on one side by a spring 40 which urges the control slide 26 into its closed position, in which both passages are blocked. Furthermore, each of the two ends of the control slide 26 is exposed to a control pressure which tries to force the control slide 26 into the opposite position.
  • the control connections of the valve 24 are each connected to a changeover valve 42, 44.
  • the two changeover valves 42, 44 are each 3/2-way valves. They are mechanically coupled to one another, which is indicated by the rod 46, and can be switched over together in any manner (for example electrically, hydraulically or mechanically) by an actuating element 48.
  • the two changeover valves 42, 44 are expediently implemented by a common valve slide. They were only shown as two separate parts for the sake of clarity.
  • the position of the changeover valves 42, 44 shown in FIG. 1 corresponds to the open center operation, in which a hydraulic function which is open in the middle position and is designed for constant current operation is connected to the valve arrangement 16.
  • the control connection of the valve 24, which is on the side of the spring 40 is connected to the reservoir 22 and the other control connection is connected to the supply line 34 leading to the control valve 12.
  • the hydraulic system shown in FIG. 1 works as follows: If the control valve 12 is in its neutral position, the supply line 34 is connected to the reservoir 22 and is depressurized. So that the two control connections of the valve 24 are connected to the reservoir 22, so that the control slide 26 shifts due to the force of the spring 40 into its position shown in Fig. 1 and both passages locks.
  • the hydraulic pump 10 does not deliver any hydraulic fluid to the hydraulic function 12, 14. If a pressure is still present at the load signaling connection 18, it is reduced via the throttle point 20 to the reservoir 22. The hydraulic pump 10 regulates down to its standby pressure.
  • control valve 12 If the control valve 12 is moved into a working position, the outflow from the feed line 34 to the reservoir 22 is blocked. A permanent control current flows through the orifice 38 and the channel 36, through which a pressure builds up in the feed line 34. This pressure communicates via the changeover valve 44 to the control connection of the valve 24 opposite the spring 40 and moves the control slide 26 into its open position in which the two passages are open.
  • the hydraulic pump 10 now supplies hydraulic fluid to the hydraulic cylinder 14 via the throttle point 28, the valve 24, the check valve 30, the feed line 34 and the control valve 12, so that the hydraulic cylinder 14 performs the desired movement. Furthermore, the load signaling connection 18 of the hydraulic pump 10 is connected to the pressure of the supply line 34, so that the hydraulic pump 10 regulates and provides its maximum system pressure for supplying the hydraulic function.
  • control valve 12 If the control valve 12 is brought back into its central position in order to interrupt the actuation of the hydraulic cylinder, the supply line 34 is depressurized again, the valve 24 closes and the hydraulic pump 10 regulates to its standby pressure.
  • the check valve 30 prevents a load drop.
  • the throttle point 32 lying in parallel with the check valve 30 enables a leakage current against the blocking direction of the check valve 30, so that a gradual pressure equalization can take place.
  • this throttle point 32 is not required for the open center application.
  • a check valve 50 is arranged between the supply line 34 and the reservoir 22, which enables a suction of hydraulic fluid from the reservoir 22 if necessary.
  • FIG. 2 The hydraulic system shown in FIG. 2 is essentially identical to that shown in FIG. 1. The same reference numbers have therefore been used for the same components.
  • the hydraulic system is used to supply a constant-current hydraulic function that contains an open-center control valve 12, in FIG. 2 a constant-pressure hydraulic function with a closed-center control valve 13 is shown as a consumer.
  • the changeover valves 42, 44 shown in FIG. 2 are accordingly in their position for closed-center operation.
  • a shuttle valve 52 is arranged between the pump outlet and the feed line 34, the center connection of which can be connected via the changeover valve 44 to the control connection of the valve 24 opposite the spring 40. Although this shuttle valve 52 is also shown in FIG. 1, it has not yet been described since it has no significance for the open center operation.
  • the hydraulic system shown in FIG. 2 works as follows: If the control valve 13 is in its neutral position, the supply line 34 is blocked. The pump outlet pressure is present in it, which is communicated via the orifice 38, the channel 36 and the orifice 32 or the check valve 30. The pump outlet pressure is also present at the two control connections of the valve 24 via the orifice 38 and the changeover valve 42 or via the changeover valve 52 and the changeover valve 44. The control slide 26 of the valve 24 is therefore held due to the force of the spring 40 in its closed position, in which both passages are closed. If a pressure is still present at the load signaling connection 18, it is reduced via the throttle point 20 to the reservoir 22. The hydraulic pump 10 regulates down to its standby pressure.
  • control valve 13 If the control valve 13 is switched into a working position, the pressure drops in the supply line 34, and the control connection of the valve 24 on the side of the spring 40 is relieved via the channel 36 and the changeover valve 42.
  • the control slide 26 is moved by the pump outlet pressure present at the other control connection into its open position, in which there is a free flow from the hydraulic pump 10 to the control valve 13. Furthermore, the pressure of the supply line 34 is present at the load signaling connection, so that the load signal required for pump control is given and the hydraulic pump 10 is regulated.
  • the pressure drop generated over the adjustable throttle point 28 serves to stabilize the system.
  • the pressure in the feed line 34 switches the shuttle valve 52 from its position shown, so that the feed line 34 via the shuttle valve 52 and the switch valve 44 with the the spring 40 opposite control connection of the valve 24 is connected.
  • the shuttle valve 52 ensures that the higher of the pressures of the pump outlet or the supply line is present at the control connection.
  • the check valve 30 also serves to secure a load on the hydraulic cylinder 14.
  • the throttle point 32 allows a pressure reduction in the supply line 34 if the control valve 13 is closed against a high load pressure.
  • the passage opening of the throttle point 32 is generally dimensioned smaller than that of the orifice 38, so that the pressure at the control connection of the valve 24 located on the spring side is primarily influenced by the pump outlet pressure.
  • valve block 60 which essentially contains the elements of the valve arrangement 16 shown in FIGS. 1 and 2. Elements with the same effect have therefore been given the same reference symbols.
  • the valve block 60 has a pump connection 62 which can be connected to a hydraulic pump 10, a tank connection 64 which can be connected to a reservoir 22, a working connection 66 which can be connected to a hydraulic function via a feed line 34 and one to the load-reporting connection 18 of the hydraulic pump 10 connectable signaling connection 68.
  • a control slide 26 is slidably guided, which contains two control sections 72, 74 and is forced into its left position according to FIG. 3 by the force of a spring 40.
  • the first control section 72 opens or closes a passage 76 between the pump connection 62 and the working connection 66, while the second control section 74 opens or closes a passage 78 between a channel 36 and the signaling connection 68.
  • the control slide 26 is shown in its right position, in which both passages 76, 78 are open.
  • the right end face of the control slide 26 is connected to a changeover valve 42, through which it can be connected either to the tank connection 64 or to the pump connection 62 via a channel 36 containing an orifice 38.
  • the left end face of the control slide 26 can be connected to the working connection 66 by a shuttle valve 52 or to the pump connection 62 via a changeover valve 44.
  • the shuttle valve 52 is designed such that it applies the higher of the two pressures, which act on the working connection 66 or on the pump connection 62, to the left end face of the control slide 26.
  • the two changeover valves 42, 44 are shown in their closed center position. By twisting, they can be brought into their open center position.
  • a valve insert 80 is inserted into the bore of the working connection 66 and counteracts the force of a spring 82 an outlet opening is pressed to close it.
  • This valve insert 80 forms the check valve 30. It has a central bore 84 which serves as a throttle point 32 and allows gradual pressure equalization.
  • a throttle point 28 designed as a rotary slide valve is provided in the area of the pump connection 62.
  • a pressure drop can be set on the one hand, so that the load signal is a certain amount, for example by 30 bar, less than the pump outlet pressure.
  • the throttle point 28 can be used to make a current setting.

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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)
  • Fluid-Pressure Circuits (AREA)
  • Valve Device For Special Equipments (AREA)
  • Lubricants (AREA)
EP94104713A 1993-04-05 1994-03-24 Système hydraulique pour alimentation de fonctions hydrauliques ouvertes ou fermées Expired - Lifetime EP0620371B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4311191A DE4311191C2 (de) 1993-04-05 1993-04-05 Hydrauliksystem zur Versorgung offener oder geschlossener Hydraulikfunktionen
DE4311191 1993-04-05

Publications (2)

Publication Number Publication Date
EP0620371A1 true EP0620371A1 (fr) 1994-10-19
EP0620371B1 EP0620371B1 (fr) 1997-09-03

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EP94104713A Expired - Lifetime EP0620371B1 (fr) 1993-04-05 1994-03-24 Système hydraulique pour alimentation de fonctions hydrauliques ouvertes ou fermées

Country Status (6)

Country Link
US (1) US5419129A (fr)
EP (1) EP0620371B1 (fr)
AT (1) ATE157747T1 (fr)
CA (1) CA2120052C (fr)
DE (2) DE4311191C2 (fr)
DK (1) DK0620371T3 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102010006858A1 (de) 2010-02-04 2011-08-04 Daimler AG, 70327 Ventilsystem für ein Hydrauliksystem eines Kraftfahrzeuges

Families Citing this family (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19617790A1 (de) * 1996-05-03 1997-11-13 Freimut Joachim Marold Verfahren und Vorrichtung zur regenerativen Nachverbrennung und schaltbarer Verteiler für Fluide
US6490962B1 (en) * 2001-05-17 2002-12-10 The Stanley Works Hydraulic tool with an OC/CC selector
US6672399B2 (en) 2001-10-19 2004-01-06 Deere & Company Hydraulic diverting system for utility vehicle
US6679340B1 (en) * 2002-07-23 2004-01-20 Izumi Products Company Hydraulic tool
CA2408407A1 (fr) * 2002-10-16 2004-04-16 David Gary Mccrea Rampe de pulverisateur flottante suspendue
KR100518769B1 (ko) * 2003-06-19 2005-10-05 볼보 컨스트럭션 이키프먼트 홀딩 스웨덴 에이비 유압펌프 토출유량 제어회로
US6990888B2 (en) * 2003-07-25 2006-01-31 Greenlee Textron Inc. Mechanism for switching between closed and open center hydraulic systems
CA2487184C (fr) * 2004-11-05 2012-04-10 Stanislaus Montgomery Shivak Systeme de commande de fleche
DE102005059351A1 (de) 2005-12-09 2007-06-21 Claas Selbstfahrende Erntemaschinen Gmbh Hydrauliksystem für eine selbstfahrende Erntemaschine
CA2630199A1 (fr) * 2008-05-01 2009-11-01 Multimatic Inc. Systeme hydraulique auxiliaire de vehicule
US8267004B2 (en) * 2009-05-20 2012-09-18 Lifetime Enterprises, Llc Adaptable hydraulic control system
KR101609882B1 (ko) * 2009-12-17 2016-04-06 두산인프라코어 주식회사 건설기계의 유압시스템
US20130168073A1 (en) * 2011-12-30 2013-07-04 Cnh America Llc Work vehicle fluid heating system
US9403434B2 (en) 2014-01-20 2016-08-02 Posi-Plus Technologies Inc. Hydraulic system for extreme climates
US9702118B2 (en) * 2014-11-19 2017-07-11 Caterpillar Inc. Hydraulic regenerative and recovery parasitic mitigation system
US9470246B1 (en) 2015-06-05 2016-10-18 Cnh Industrial America Llc Hydraulic actuation system for work machine
WO2017041848A1 (fr) * 2015-09-10 2017-03-16 Festo Ag & Co. Kg Système de fluide et soupape de processus
EP3258116B1 (fr) * 2016-06-15 2019-12-25 HAWE Hydraulik SE Module hydraulique avec soupape de régulation 2-voies contrôlé par pression
CN107654426A (zh) * 2017-10-30 2018-02-02 湖南五新隧道智能装备股份有限公司 一种凿岩台车及其冲击控制液压系统
CN114263656B (zh) * 2021-11-11 2023-03-24 中联重科股份有限公司 闭式液压系统及机械设备

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3522450A1 (de) * 1985-06-22 1987-01-02 Bosch Gmbh Robert Hydraulische einrichtung zum betaetigen eines verstellteils

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3865013A (en) * 1973-11-12 1975-02-11 Worthington Cei Auxiliary tool control circuit
US4821514A (en) * 1987-06-09 1989-04-18 Deere & Company Pressure flow compensating control circuit
JP2582266B2 (ja) * 1987-09-29 1997-02-19 新キヤタピラー三菱株式会社 流体圧制御システム
JPH04210101A (ja) * 1990-11-30 1992-07-31 Komatsu Ltd 油圧回路
US5245827A (en) * 1992-08-03 1993-09-21 Deere & Company Supply valve arrangement for closed center hydraulic system

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3522450A1 (de) * 1985-06-22 1987-01-02 Bosch Gmbh Robert Hydraulische einrichtung zum betaetigen eines verstellteils

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
HANS ESDERS, CLAUS HOLLÄNDER JENS MÖLLER, GÜNTER TEWES: "Hydraulik in Traktoren und Landmaschinen - Neues von der Agritechnica '91", ÖLHYDRAULIK UND PNEUMATIK, vol. 36, no. 3, March 1992 (1992-03-01), MAINZ, DE, pages 139 - 147 *
HEINRICH LÖDIGE: "Nutzbare Leistung einer LS-Hydraulik", ÖLHYDRAULIK UND PNEUMATIK, vol. 36, no. 4, April 1992 (1992-04-01), MAINZ, DE, pages 234 - 241, XP000263823 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102010006858A1 (de) 2010-02-04 2011-08-04 Daimler AG, 70327 Ventilsystem für ein Hydrauliksystem eines Kraftfahrzeuges

Also Published As

Publication number Publication date
EP0620371B1 (fr) 1997-09-03
DE59403919D1 (de) 1997-10-09
US5419129A (en) 1995-05-30
DE4311191C2 (de) 1995-02-02
CA2120052A1 (fr) 1994-10-06
DK0620371T3 (da) 1998-04-20
CA2120052C (fr) 1999-11-02
ATE157747T1 (de) 1997-09-15
DE4311191A1 (de) 1994-10-13

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