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
  • E02F9/2217—Hydraulic or pneumatic drives with energy recovery arrangements, e.g. using accumulators, flywheels
• • 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
  • E02F9/2203—Arrangements for controlling the attitude of actuators, e.g. speed, floating function
  • E02F9/2207—Arrangements for controlling the attitude of actuators, e.g. speed, floating function for reducing or compensating oscillations
• • 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
  • F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
  • F15B1/02—Installations or systems with accumulators
  • F15B1/021—Installations or systems with accumulators used for damping

Definitions

• Hydraulic control arrangement for a mobile working device
• the invention relates to a hydraulic control arrangement for a mobile implement according to the preamble of patent claim 1.
• DE 44 16 228 AI shows a hydraulic control arrangement in which the lift cylinder of a loading shovel of a wheel loader can be supplied with pressure medium via a directional control valve and a damping valve. Via the directional control valve, the two pressure chambers of each lift cylinder are connected to a pump or a tank to raise or lower the loading shovel. In a spring-biased middle position of this directional valve, the connections to the pressure chambers are shut off. With the damping valve in the neutral position of the directional valve, the pressure chambers of the lift cylinders can either be with a tank (floating position) or the in
• Vibrations of the loading shovel can be damped. These pitching vibrations occur particularly when the loading shovel is full and the vehicle is traveling at high speeds.
• the damping valve can be in the switch position
• Vibration vibration damping can be switched by the driver or automatically as soon as pitch vibrations occur or as soon as the driving speed exceeds a predetermined limit.
• the switch position "float" of the damping valve is controlled by the driver, for example, when the loading shovel is to be pulled over the ground in order to level the ground.
• the damping valve has to be designed to be comparatively complex, since it has two working lines connected to the lift cylinders and at least four connections (connections for the aforementioned working lines, tank connection, connection) to implement the two functions “swimming” and “pitching vibration damping” for hydraulic accumulators).
• the invention has for its object to provide a hydraulic control arrangement for a mobile implement, in which the functions "swimming" and “pitch vibration damping" are made possible with little effort.
• the hydraulic control arrangement has a directional control valve via which the pressure medium flow between the pressure chambers of the hydraulic cylinder and a pump or a tank can be controlled.
• the directional control valve is assigned a damping valve arrangement, via which
• both pressure chambers of the hydraulic cylinder can be connected to a hydraulic accumulator.
• both pressure chambers are acted upon together with the pressure in the hydraulic accumulator, so that the load acting on the hydraulic cylinder is in principle only from the rod surface, ie the differential area between the piston chamber-side pressure chamber and the piston rod-side pressure chamber is carried.
• a comparatively high pressure thus acts in the damping direction, so that practically a large load is simulated and the pitch vibration damping is accordingly more effective than in the prior art mentioned at the beginning.
• damping valve arrangement only has to be designed with a working connection, since both the pressure chambers of the hydraulic cylinder have the same pressure, ie the pressure in the hydraulic accumulator or the pressure in both the "pitch vibration damping" function and the “swimming" function be applied to the tank pressure.
• the damping valve arrangement can also be designed with a small nominal size, since only a small flow of pressure medium flows through it, which corresponds to the volume displaced by the piston rod.
• the hydraulic control arrangement can be further simplified if the directional valve in its neutral position connects the flow and drain lines leading to the two pressure chambers of the hydraulic cylinder, so that the working connection of the damping valve arrangement only has to be connected to the flow or drain line via a single damping line , so that the piping effort compared to the conventional solution is further reduced.
• the damping valve is designed as a 3/3-way valve, the two input connections being connected to the hydraulic accumulator or the tank and the working connection to the damping line leading to the drain or flow line. In the neutral position of the damping valve, these connections are blocked against one another, while in the two switching positions either the hydraulic accumulator or the tank are connected to the damping line.
• two 2/2-way valves can also be used, one of which is assigned to the "swimming" function and the other to the "pitching vibration damping" function.
• the damping valve arrangement is preferably controlled electrically, the control signals being able to be emitted by the driver, for example, by actuating switches of a pilot control device.
• the directional control valve is preferably actuated hydraulically via the pilot control device mentioned.
• the hydraulic accumulator can be designed as a piston accumulator.
• FIG. 1 shows a diagram of the hydraulic control arrangement.
• the hydraulic control arrangement 1 according to the invention is applied, for example, to two lift cylinders to supply a loading shovel of a wheel loader or backhoe loader with pressure medium.
• Only one lift cylinder 2 is shown as an example, the pressure chambers of which can be connected to a pump 6 or a tank T via a directional valve 4.
• the directional control valve 4 is actuated via a hydraulic pilot control device 8 by actuating a joystick 10 by the driver of the mobile working device.
• the pressure chambers of the lift cylinders 2 can be connected to a hydraulic accumulator 14 or the tank T via a damping valve 12.
• the damping valve 12 is electrically controlled and can be operated via switches which are arranged on the joystick 10.
• the lifting cylinders 2 supporting the loading shovel are designed as differential cylinders, the weight of the loading shovel and the load contained therein being identified by M in the figure.
• the piston chamber-side cylinder chamber 16 of the lift cylinder 2 is over a
• Flow line 20 connected to a working connection A and an annular space 18 via a drain line 22 to a working connection B of the directional valve 4.
• This is designed, for example, as a proportionally adjustable directional control valve, with a pump connection P connected to the pump 6 being connected to the working connection A in the positions labeled "LIFT" of a control slide, not shown, while the working connection B is connected to a tank connection connected to the tank T.
• S is connected, so that the pump 6 conveys pressure medium into the cylinder space 16 and pressure medium is displaced from the annular space 18 into the tank T - the load M is raised, the speed being dependent on the path of the control spool and / or the delivery quantity of the pump 6 depends.
• the load M is lowered by connecting the cylinder space 16 to the tank T and the annular space 18 to the pump 6.
• the directional control valve 4 is actuated hydraulically via control lines 24, 26, via which control surfaces of the control slide can be acted upon by a control pressure difference in order to move the control slide into the desired position.
• These control pressures are generated via the hydraulic pilot control device 8, via the one.
• System control pressure can be reduced to the desired control pressure by means of pressure-reducing valves which can be actuated as a function of the position of the joystick 10 and which can be tapped at the control connections 1, 2 of the pilot control device 8.
• pressure-reducing valves which can be actuated as a function of the position of the joystick 10 and which can be tapped at the control connections 1, 2 of the pilot control device 8.
• the control slide of the directional valve 4 is biased by springs 28, 30 into a central position in which the two working connections A, B are connected to one another and the two input connections P and S are blocked. That the two pressure chambers are in this middle position
• the damping valve 12 is designed in the illustrated embodiment as a 3/3-way valve, with an output or working port A via a
• Damping line 32 is connected to the drain line 22.
• a tank connection T of the damping valve 12 is connected to the tank T and a pressure connection P to a hydraulic accumulator 14.
• the valve spool of the damping valve 12 is via centering springs 33, 34 in biased a neutral position in which the three connections A, T, P are shut off from each other.
• the damping valve 12 is controlled electrically, the actuation of the valve slide taking place via electromagnets 36, 38 which are connected to switches on the joystick 10 via signal lines 40, 42.
• the damping valve 12 is designed as a switching valve, the working port A being connected to the tank port T in its switching position labeled (a), so that both the annular space 18 and the pressure chamber 16 are connected to the tank T when the directional control valve 4 is not actuated - the Switch position marked with (a) thus stands for the "swimming" function, in which the loading shovel lies practically only on the ground due to its own weight and the loaded load, and when leveling follows unevenness in the ground.
• the damping valve 12 Corresponds to piston rod volume. Because of this Comparatively low pressure medium volume flow, the damping valve 12 can be designed with a smaller nominal width than in conventional solutions. As explained above, the damping valve 12 can be switched over to its "pitch vibration damping" function by actuating a switch. In principle, it is also possible to switch automatically to this function when a certain driving speed has been reached or the vibration amplitude exceeds a predetermined maximum value.
• the damping valve 12 is switched back to its neutral position by switching off the electromagnets 36, 38 and the directional control valve 4 is set to one of its "LIFT” or "LOW” positions by means of the pilot device 8 Extend or retract lift cylinder 2.
• the pilot device 8 Extend or retract lift cylinder 2.
• the damping valve 12 can also be designed by two 2/2-way valves, one of which is assigned to the "swimming" function and the other to the "pitching vibration damping" function.
• the hydraulic accumulator 14 is preferably designed as a piston accumulator, since it is particularly well suited for high pressures.
• damping line 32 can also be connected to the flow line 20.
• connection of the two pressure chambers 16, 18 can also be integrated into the damping valve 12.
• a hydraulic control arrangement for a mobile working device for example one
• Backhoe loader or a wheel loader being a Working tool of the implement can be actuated by means of a hydraulic cylinder, the pressure chambers of which can be connected to a hydraulic accumulator 14 for damping pitching vibrations of the working tool.

Landscapes

• 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)
• Lifting Devices For Agricultural Implements (AREA)

Applications Claiming Priority (2)

Publications (2)

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• 2003
  • 2003-11-25 DE DE10354959A patent/DE10354959A1/de not_active Withdrawn
• 2004
  • 2004-11-22 AT AT04802785T patent/ATE377154T1/de not_active IP Right Cessation
  • 2004-11-22 EP EP04802785A patent/EP1687542B1/fr not_active Not-in-force
  • 2004-11-22 US US10/576,419 patent/US7383682B2/en not_active Expired - Fee Related
  • 2004-11-22 DE DE502004005397T patent/DE502004005397D1/de active Active
  • 2004-11-22 WO PCT/DE2004/002574 patent/WO2005052380A1/fr active IP Right Grant

Non-Patent Citations (1)

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