EP2199623A2 - Système hydraulique - Google Patents

Système hydraulique Download PDF

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Publication number
EP2199623A2
EP2199623A2 EP09177885A EP09177885A EP2199623A2 EP 2199623 A2 EP2199623 A2 EP 2199623A2 EP 09177885 A EP09177885 A EP 09177885A EP 09177885 A EP09177885 A EP 09177885A EP 2199623 A2 EP2199623 A2 EP 2199623A2
Authority
EP
European Patent Office
Prior art keywords
delivery volume
hydraulic system
variable displacement
displacement pump
control unit
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.)
Withdrawn
Application number
EP09177885A
Other languages
German (de)
English (en)
Other versions
EP2199623A3 (fr
Inventor
Wolfgang Bauer
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.)
Deere and Co
Original Assignee
Deere and Co
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
Application filed by Deere and Co filed Critical Deere and Co
Publication of EP2199623A2 publication Critical patent/EP2199623A2/fr
Publication of EP2199623A3 publication Critical patent/EP2199623A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/02—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
    • F15B11/042—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the feed line, i.e. "meter in"
    • F15B11/0423—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the feed line, i.e. "meter in" by controlling pump output or bypass, other than to maintain constant speed
    • 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
    • E02F9/2235—Control of flow rate; Load sensing arrangements using one or more variable displacement pumps including an electronic controller
    • 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
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/06—Control using electricity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/10—Other safety measures
    • 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
    • F15B2211/255—Flow control functions
    • 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
    • F15B2211/615—Filtering means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/633—Electronic controllers using input signals representing a state of the prime mover, e.g. torque or rotational speed
    • 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
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6343—Electronic controllers using input signals representing a temperature
    • 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
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6346—Electronic controllers using input signals representing a state of input means, e.g. joystick position
    • 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
    • F15B2211/665—Methods of control using electronic components
    • F15B2211/6652—Control of the pressure source, e.g. control of the swash plate angle
    • 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
    • F15B2211/665—Methods of control using electronic components
    • F15B2211/6654—Flow rate control

Definitions

  • the invention relates to a hydraulic system with a drive motor, a driven by the drive motor hydraulic variable displacement pump, driven by the variable displacement hydraulic consumer and an electronic control unit, wherein the variable displacement pump is equipped with a winningvolumenverstellech, at which a engageable with an adjusting piston in a stop maximum delivery volume of the variable is adjustable.
  • Agricultural machines are known, for example tractors, or other types of working machines, such as construction machines or telescopic loaders, which have a hydraulic system with which one or more hydraulic consumers are operated, eg hydraulic cylinders, hydraulic motors or other hydraulically operated components.
  • hydraulic systems include hydraulic pumps which translate directly or via a rigid transmission gear into fast or slow, with the drive shaft, a drive motor are connected.
  • the maximum deliverable volume flow of the hydraulic pump thus changes with the speed of the drive motor. The faster the drive motor turns, the larger the volume flow that can be delivered by the hydraulic pump.
  • hydraulic variable displacement pumps so-called hydraulic variable displacement pumps, as they are used today as state of the art, the subsidized maximum delivery volume can be adapted to the demand required by the hydraulic consumer.
  • LS signal load-sense signal reported by the consumer
  • the delivery flow regulator of an LS-controlled variable displacement pump now works in such a way that it adjusts the delivery volume flow of the variable displacement pump so that the preset control pressure difference, which can be set permanently on the delivery flow regulator via an adjusting spring, is always kept constant.
  • the exact mode of action of such a (pressure) flow regulator can be read in the relevant literature and is as such prior art.
  • the delivery volume flow which can be delivered from a hydraulic valve to a consumer, for example a hydraulic cylinder or a hydraulic motor, is directly dependent on this preset control pressure difference.
  • a certain pressure to be regulated is set, which forces the variable to maintain a set pressure corresponding control pressure difference between the output of the variable and consumer (LS signal) upright.
  • the adjustable in accordance with an adjusting piston or adjustable counselnverstelltechnik the variable and starts to promote a corresponding flow rate.
  • the adjusting piston is hydraulically connected to the flow controller and changes its position in dependence on the control pressure difference present or set on the flow regulator.
  • the randomlyvolumenverstellhim may for example comprise a swash plate which is connected to control or reciprocating piston, wherein by rotating the swash plate, the rotational movement is converted into a longitudinal movement of the reciprocating piston.
  • the volume flow delivered by the variable displacement pump flows through the lines and valves of the hydraulic system and generates certain pressure losses in the lines and at the respective valves to the consumers.
  • the pressure which then sets behind the valves or at the consumer, is reported as load pressure (LS signal) back to the variable displacement pump (via a load pressure line (LS line), which is connected to the flow regulator) and causes the variable displacement pump to do so
  • LS signal load pressure
  • LS line load pressure line
  • valves which are farther away from the variable displacement pump than other valves will allow less volumetric flow to reach a consumer, although there are valves of the same type.
  • valves that report an increased load signal to the pump such as in the EP 176 0 325 A2 is disclosed.
  • EP 349 092 B1 discloses another way to allow high volume flows at low engine speeds, but to limit the flow rate at high engine speeds.
  • the maximum delivery volume delivered by the variable displacement pump is limited, the delivery rate of the variable displacement pump being measured (eg by measuring the position of the delivery volume adjustment mechanisms, eg the adjustment angle of an adjusting disc or swashplate) and monitored.
  • these variable displacement pumps and the corresponding control electronics are complex and expensive.
  • the object underlying the invention is seen to provide a hydraulic system of the type mentioned, by which the aforementioned problems are overcome.
  • a hydraulic system is to be created with simple, safe and cost-effective means, which provides a high maximum delivery volume at low input speeds, but limits this at higher input speeds to a certain maximum value.
  • a hydraulic system of the type mentioned above is formed such that the stop of the originallyvolumenverstelltechnik by the control unit controllable actuating means comprises, through which the maximum Volume of the variable displacement pump via the electronic control unit is changeable, wherein the electronic control unit detects a drive speed-dependent signal, as a function of which a control signal for the controllable actuating means can be generated by the control unit, which changes the maximum displacement of the variable displacement pump on the constructivevolumenverstelltechnik by adjusting the stop.
  • a preset maximum delivery volume of the variable at the winningvolumenverstellica depending on the drive speed can be selectively changed, so that with increasing drive speeds, the maximum delivery volume preferably proportionally adjusted and a maximum flow rate is not exceeded.
  • the adjusting piston of the delivery volume adjustment unit connected hydraulically to the delivery flow regulator is adjusted.
  • This setting is suitable for example to promote a volume flow through the valves up to a size of V1 l / min.
  • the variable displacement pump has the potential to deliver volumetric flows of Vmax l / min, which would result in high losses in the lines and valves.
  • this pump now delivers, for example, a maximum of Vleer l / min (Vleer ⁇ V1 ⁇ Vmax) and with increasing drive speed (U +) the volumetric flow (V) increases while the maximum delivery volume remains the same.
  • the corresponding functions and calculation algorithms are preferably stored in the electronic control unit.
  • a corresponding control signal is generated by the control unit and directed to the actuating means of the stop on the adjusting piston of the delivery volume adjusting unit for the purpose of controlling the same.
  • the actuating means By controlling the actuating means, the maximum delivery volume of the variable displacement pump is variably controlled as a function of the drive speed.
  • the maximum delivery volume of the variable displacement pump can be reduced by actuating the adjusting means on the stop of the adjusting piston.
  • the presettable drive speed value which triggers the adjustment of the maximum delivery volume, can preferably be predetermined via an input module on a driver's display of a working device or via another suitable input interface of the control unit. However, it may also vary according to the size of the Adjusting pump already given a fixed drive speed value and stored in the control unit.
  • the control unit When a presettable input speed value is exceeded, the maximum delivery volume of the variable displacement pump is changed by controlling the adjusting means at the stop of the adjusting proportional to the drive speed, the control unit reduces the maximum delivery volume flow with increasing input speed and increases with decreasing input speed.
  • the control signal generated by the control unit is preferably continuously adapted to a drive speed change, so that an operator of the system does not notice the change in the maximum delivery volume directly.
  • an operator can virtually override the control of the control unit on the winningvolumenverstelltechnik or at the stop of the adjusting piston provided actuating means and by appropriate inputs on the adjusting means, for example on an input module or on an input button with thumbwheel or a potentiometer the drive speed-dependent control function Disable control unit and by direct specification of an input via the setting means input signal, the control signal modify, so that despite initial drive speed-dependent generation of a control signal, the signal input by the setting means is prioritized.
  • This makes it possible to bypass a drive-speed-dependent control and, for example, to operate the hydraulic system with a high maximum delivery volume even at high drive speeds or to set any delivery volume flow at any desired drive speed.
  • variable displacement variable displacement pump would not help much if all the lines and valves were not also increased.
  • it may be useful to increase the maximum delivery volume by appropriately adjusting the stop of the adjusting specifically to ensure that at higher input speeds, the variable displacement or the winningvolumenverstelltechnik the variable or the swash plate can pivot fully to provide a higher flow rate ,
  • the hydraulic system may further include a temperature sensor that detects the temperature in the hydraulic system and provides a corresponding signal to the control unit.
  • the viscosity of a hydraulic fluid depends on the temperature, so that it may be advantageous at low temperatures, or at a high viscosity of the hydraulic fluid, to adjust the maximum delivery volume further depending on the viscosity or temperature, for example, to increase.
  • the adjusting means on the stop of the adjusting piston preferably comprise an electric motor, which is controllable by the control unit and can adjust the stop. Furthermore, it is also conceivable to use an electromagnet which adjusts the stop. Preferably, the adjustment of the stop should be done directly, for example via a stepper motor, which is connected to a spindle drive, which converts a rotational movement of the motor into a linear movement of a spindle whose end can act as a stop for the adjusting.
  • the adjusting piston in turn stops either itself a stop for theRONvolumenverstelltechnik (eg for the swash plate) is or moves such a stop in a position by which the pivot angle of the beneficiavolumenverstelltechnik is adjusted or limited.
  • This adjustment can be accomplished electrically or electromagnetically as mentioned above, but also hydraulically, pneumatically or purely mechanically, with an electrical or electromagnetic adjustment of the stop of the adjusting piston being preferred, since this is easier to handle than other types of adjustment.
  • the adjustment of the stop can now increase or decrease the maximum delivery volume of the variable.
  • the adjustment for example, via a proportional magnet, which is effective in both directions, take place.
  • it is also conceivable to allow an adjustment in one direction only. Since it can always happen that the electronics on the work vehicle fails, it makes sense to provide measures that prevent failure of the electronics that it comes to a failure of the entire hydraulic system. For this reason, the use of a stepping motor for the adjustment of the stop of the adjusting piston is particularly suitable.
  • the stepper motor has the advantage that it has a certain self-locking and can be moved very precisely in a specific position (angle of rotation), which he no longer leaves, unless he gets a new control signal or a very strong force pulls at him.
  • Such a stepper motor can be connected, for example, to an adjusting spindle for adjusting the maximum stroke of an adjusting piston on a constructivevolumenverstelltechnik and can then very accurately and very quickly rotate this adjusting spindle depending on the control signal, so that the position of the adjusting, and thus the maximum pivot angle of the swash plate constructivevolumenverstelltechnik or the maximum delivery volume of the variable, very sensitive can be adjusted.
  • the adjusting spindle or the end of the adjusting spindle engaged with the adjusting piston constitutes the stop of the adjusting piston. Should the electronics fail, the stepping motor would simply remain in its last position and thus ensure that at least one certain minimum operation the hydraulic system remains ensured.
  • An inventive hydraulic system is used in work vehicles, which are used in particular in agriculture. These include agricultural vehicles, such as tractors with or without front loader and telescopic loaders. Furthermore, such a hydraulic system is also suitable for use in construction machines, such as excavators or wheel loaders.
  • the hydraulic system according to the invention enables optimum operation of a hydraulic system in all drive-dependent operating states of the vehicle and serves, in particular, to reduce power losses and to provide large volume flows at low drive speeds. Furthermore, existing smaller line cross-sections and valves can be used in spite of a variable displacement pump. If required, very large volume flows are possible despite small pipe cross-sections and valves. A maintenance of existing valves and lines, regardless of the use of a larger variable, is possible. Furthermore, despite electronic control of the flow control valve in case of failure the electrical system is ensured that the existing hydraulic system is still available.
  • FIG. 1 shows a hydraulic system 10 for operating a hydraulic consumer 12, for example a hydraulic cylinder for raising and lowering a front loader 14.
  • the hydraulic system 10 comprises a hydraulic tank 16, a hydraulic variable displacement pump 18 with a flow regulator 20 for setting a control pressure difference between variable displacement pump 18 and load 12, a pressure limiter 22 for limiting the operating pressure for the variable displacement pump 18, and an adjusting piston 23 for adjusting the via a winningvolumenverstelltechnik 24th Furthermore, a stop 23 'for the adjusting piston 23 is provided, which can be brought into engagement with the adjusting piston 23 and with which a maximum delivery volume of the variable displacement pump 18 is variably adjustable.
  • the Variable displacement pump 18 is driven by a drive motor 25. Between the consumer 12 and variable displacement pump 18, a hydraulic control valve 26 is connected, via which the hydraulic consumer 12 is controlled.
  • a load pressure line 28 is connected, which is connected to the flow regulator 20, wherein the load pressure line 28 has a connected to the tank 16 pressure relief diaphragm 29 and a closing in the direction of the consumer 12 check valve 30, wherein the check valve 30 between the Pressure relief diaphragm 29 and the consumer 12 is arranged.
  • the hydraulic system 10 has an electronic control unit 32 which is connected to a speed sensor 34 and an adjusting device 36.
  • a temperature sensor 37 is provided which detects the temperature of a hydraulic fluid in the hydraulic system 10 and supplies a corresponding signal to the electronic control.
  • the stop 23 'of the adjusting piston 23 of the randomlyvolumenverstelltechnik 24 has adjusting means 38, which are designed as electric motor, preferably as a stepping motor, and are controlled by the electronic control unit 32.
  • adjusting means 38 which are designed as electric motor, preferably as a stepping motor, and are controlled by the electronic control unit 32.
  • an electromagnetic proportional solenoid (not shown) may be used as well.
  • the proportional magnet is preferably also effective in both directions, wherein generally an adjustment of the winningvolumenverstelltechnik 24 in only one direction is quite conceivable, so that, for example, only a reduction of the maximum delivery volume is possible.
  • the drive motor 25 is connected directly to the variable displacement pump 18, which is shown here only by way of example.
  • the electronic control unit 32 may receive input signals from the adjustment device 36, which then takes into account in the generation of a control signal for the actuating means 38. In the generation of a control signal, only a speed signal supplied by the rotational speed sensor 34 is considered in the first place, as a function of which the electronic control unit 32 generates the control signal for the actuating means 38. However, if an additional input via the adjustment 36, so the first based on the speed signal control signal is modified accordingly.
  • the delivery flow regulator 20 is preset via a biasing spring 40 with a fixed control pressure difference value.
  • a pressure difference which is the delivery flow controller 20 via the load-sensing pressure line 28 and via a connected to the output of the variable displacement pump 18 control pressure line 42 is set.
  • the adjusting piston 23 connected to the delivery flow regulator 20 via the pressure limiter 22 is brought into a corresponding control position (stroke position).
  • the delivery volume adjusting unit 24 of the variable displacement pump 18 is adjusted.
  • the delivery volume of the variable displacement pump 18 is controlled or regulated in such a way that the adjusting piston is forced into a control position (stroke position) which is subject to the pressure conditions prevailing in the delivery flow regulator 20 via the regulating pressure differential value set on the delivery flow regulator 20.
  • the regulating pressure difference value on the delivery flow regulator 20 can be adjusted via the pretensioning spring 40 so that the regulating pressure difference value can be adjusted via the adjusting means 38 connected to the pretensioning spring 40.
  • the adjusting piston 23 can be limited by a spindle drive 41 in its position, wherein one end of the spindle drive 41 and the spindle is connected to the adjusting means 38 and the other end serves as a stop 23 'for the adjusting piston 23.
  • the adjusting piston 23 is thereby limited by the stop 23 'on the spindle drive 41 in its displaceability, wherein the limitation by the stop 23' determines the maximum delivery volume of the variable displacement pump 18.
  • the stop is thus on the spindle drive 41 adjustable or longitudinally displaceable in its position, wherein the maximum displacement (stroke) of the adjusting piston 23 in one direction by the spindle drive 41 and by the stop 23 'is specified.
  • the adjusting piston 23 is also with the randomlyvolumenverstellmaschine 24, for example, with a poppet located there (not shown), connected and limited within its maximum Lekssverschiebles the maximum stroke of the control piston of the variable displacement pump 18, for example by limiting the maximum pivot angle of the swash plate so that depending on the speed sensor 34 supplied Signal control of the adjusting means 38 on the stop 23 'of the adjusting piston 23 of the randomlyvolumenverstelltechnik 24 and thus an adjustment of the maximum delivery volume of the variable displacement pump 18 can be made.
  • stored or stored threshold values are preferably implemented in the electronic control unit 32, by means of which a corresponding control program can be started so that, for example, the maximum delivery volume of the variable displacement pump 18 is reduced further as a function of the further increasing speed, for example, when a predeterminable speed value is reached at the drive motor 25 is to limit the maximum delivery volume. If the maximum delivery volume of the variable displacement pump 18 is always exhausted during operation, it is also possible to speak of a direct control or regulation of the delivery volume flow, since then the delivery volume flow can be exhausted by exhausting the entire maximum delivery volume of the variable displacement pump limited by the stop 23 'of the adjusting piston 23 18 results.
  • an operator can now "lever out” or “override” the preset threshold values, so that independently of the rotational speed, a control of the actuating means 38 which can be predetermined via the adjusting means 36 can take place.
  • the maximum delivery volume be set to a constant value via the adjusting means 36, wherein the control unit 32 then performs the control of the actuating means 38, regardless of the rotational speed of the drive motor 25.
  • the adjusting means 36 may comprise a plurality of occupied switches or an input display or an adjustable potentiometer, etc., with which corresponding setting variables can be specified.
  • activation or deactivation of the speed-dependent control of the delivery volume adjustment unit 24 can also take place via the adjustment means 36.
  • the temperature sensor 37 detects the temperature of the hydraulic fluid and supplies a corresponding temperature signal to the control unit 32.
  • the control unit 32 can change the maximum delivery volume by adjusting the stop 23 'both as a function of the drive rotational speed and as a function of the temperature or control or regulate.
  • the maximum delivery volume can be additionally reduced or increased depending on the temperature of a hydraulic fluid of the hydraulic system 10.
  • Corresponding control signals are generated by control functions or control algorithms implemented in the control unit 32 as a function of the drive speed and / or of the temperature.
  • FIG. 2 shows an agricultural vehicle 44 in the form of a tractor, which is equipped with a front loader 14, which by a in FIG. 1 described hydraulic system is operated.
  • a front loader 14 which by a in FIG. 1 described hydraulic system is operated.
  • other applications for the hydraulic system according to the invention are conceivable, for example for use in construction machines or telescopic loaders.
  • the hydraulic system according to the invention can also be used for supply other not explicitly listed hydraulic consumers are used, for example, for the supply of three-point hitches on agricultural tractors.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Control Of Fluid Gearings (AREA)
  • Control Of Positive-Displacement Pumps (AREA)
EP09177885A 2008-12-18 2009-12-03 Système hydraulique Withdrawn EP2199623A3 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE200810054876 DE102008054876A1 (de) 2008-12-18 2008-12-18 Hydrauliksystem

Publications (2)

Publication Number Publication Date
EP2199623A2 true EP2199623A2 (fr) 2010-06-23
EP2199623A3 EP2199623A3 (fr) 2013-03-06

Family

ID=42065426

Family Applications (1)

Application Number Title Priority Date Filing Date
EP09177885A Withdrawn EP2199623A3 (fr) 2008-12-18 2009-12-03 Système hydraulique

Country Status (2)

Country Link
EP (1) EP2199623A3 (fr)
DE (1) DE102008054876A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107489663A (zh) * 2017-09-27 2017-12-19 徐州工业职业技术学院 一种变量泵及运用变量泵的液压控制系统
CN107489664A (zh) * 2017-09-27 2017-12-19 徐州工业职业技术学院 一种负载敏感和容积控制式变量泵及电液控制系统
CN107542729A (zh) * 2017-09-27 2018-01-05 徐州工业职业技术学院 一种复合控制式液压泵及复合液压控制系统
DE102013005774B4 (de) * 2013-04-05 2021-01-21 Robert Bosch Gmbh Nutzung einer von einem motor angetriebenen drehzahlvariablen hydraulikpumpe als hydrostatisches getriebe
CN116906384A (zh) * 2023-07-24 2023-10-20 徐工湖北环保科技股份有限公司 一种负载敏感液压系统

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Publication number Priority date Publication date Assignee Title
DE102013005774B4 (de) * 2013-04-05 2021-01-21 Robert Bosch Gmbh Nutzung einer von einem motor angetriebenen drehzahlvariablen hydraulikpumpe als hydrostatisches getriebe
CN107489663A (zh) * 2017-09-27 2017-12-19 徐州工业职业技术学院 一种变量泵及运用变量泵的液压控制系统
CN107489664A (zh) * 2017-09-27 2017-12-19 徐州工业职业技术学院 一种负载敏感和容积控制式变量泵及电液控制系统
CN107542729A (zh) * 2017-09-27 2018-01-05 徐州工业职业技术学院 一种复合控制式液压泵及复合液压控制系统
CN116906384A (zh) * 2023-07-24 2023-10-20 徐工湖北环保科技股份有限公司 一种负载敏感液压系统

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