EP4303438A1 - Verfahren zur einstellung eines hydrostatischen fahrsystems - Google Patents

Verfahren zur einstellung eines hydrostatischen fahrsystems Download PDF

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Publication number
EP4303438A1
EP4303438A1 EP23183000.1A EP23183000A EP4303438A1 EP 4303438 A1 EP4303438 A1 EP 4303438A1 EP 23183000 A EP23183000 A EP 23183000A EP 4303438 A1 EP4303438 A1 EP 4303438A1
Authority
EP
European Patent Office
Prior art keywords
drive motor
hydraulic pump
revolutions
speed
adjusting
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.)
Pending
Application number
EP23183000.1A
Other languages
English (en)
French (fr)
Inventor
Matthias Mueller
Ronny Herrmann
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.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
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 Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP4303438A1 publication Critical patent/EP4303438A1/de
Pending legal-status Critical Current

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Classifications

    • 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
    • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
    • F04B1/12—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F04B1/26—Control
    • F04B1/28—Control of machines or pumps with stationary cylinders
    • F04B1/29—Control of machines or pumps with stationary cylinders by varying the relative positions of a swash plate and a cylinder block
    • F04B1/295—Control of machines or pumps with stationary cylinders by varying the relative positions of a swash plate and a cylinder block by changing the inclination of the swash plate
    • 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
    • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
    • F04B1/12—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F04B1/26—Control
    • F04B1/30—Control of machines or pumps with rotary cylinder blocks
    • F04B1/32—Control of machines or pumps with rotary cylinder blocks by varying the relative positions of a swash plate and a cylinder block
    • F04B1/324—Control of machines or pumps with rotary cylinder blocks by varying the relative positions of a swash plate and a cylinder block by changing the inclination of the swash plate
    • 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
    • F04B17/00—Pumps characterised by combination with, or adaptation to, specific driving engines or motors
    • F04B17/03—Pumps characterised by combination with, or adaptation to, specific driving engines or motors driven by electric motors
    • 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
    • F04B17/00—Pumps characterised by combination with, or adaptation to, specific driving engines or motors
    • F04B17/05—Pumps characterised by combination with, or adaptation to, specific driving engines or motors driven by internal-combustion engines
    • 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
    • F04B17/00—Pumps characterised by combination with, or adaptation to, specific driving engines or motors
    • F04B17/06—Mobile combinations
    • 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
    • F04B49/065—Control using electricity and making use of computers
    • 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
    • F04B49/20—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 by changing the driving speed
    • 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
    • F04B2201/00—Pump parameters
    • F04B2201/12—Parameters of driving or driven means
    • F04B2201/1201—Rotational speed of the axis
    • 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
    • F04B2203/00—Motor parameters
    • F04B2203/02—Motor parameters of rotating electric motors
    • F04B2203/0209—Rotational speed
    • 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
    • F04B2203/00—Motor parameters
    • F04B2203/06—Motor parameters of internal combustion engines
    • F04B2203/0605—Rotational speed

Definitions

  • the present invention relates to the field of a method of adjusting a hydraulic pump control system for a hydrostatic traction system, a computing unit adapted to perform such a method, an working machine includes such a computing unit, a computer program that induces a computing unit to perform such a method, and a readable storage medium on which such a program is stored.
  • a drive motor (such as a diesel engine or electric motor) is configured to ensure the rotation of one or more hydraulic pumps mechanically connected to it.
  • Such one or more hydraulic pumps enable the transformation of mechanical energy received from said drive motor into hydraulic energy, in the form of pressure.
  • At least one hydraulic motor is hydraulically connected to said one or more hydraulic pumps so as to enable the transformation of said pressure supplied by said pump into mechanical energy.
  • CVT transmission hydrostatic continuously variable transmission
  • ET pumps load-sensitive axial piston swashplate hydraulic pumps
  • Such pumps presented the characteristic that an increase in load tends to decrease the pump's tilt angle. Therefore, if, for example, the working machine starts a climb, the load that the machine has to support will go up. This will then cause the angle of inclination of the pump to decrease.
  • the advantage of these ET pumps is that the power and pressure controls are very simple.
  • the speed (the speed) of the drive motor is set directly by the driver using a hand throttle or foot pedal.
  • the speed is typically constant; the CVT transmission is controlled in such a way that a defined vehicle speed can be set via the accelerator pedal.
  • This solution has the disadvantage that too high speeds cause inefficiency of the system, and that for too low speeds it forces the driver to make a manual correction so as to ensure the necessary power to drive the working machine on which said hydrostatic drive system is arranged.
  • variable speed serves as a reference variable for setting the transmission ratio.
  • the goal is to provide a method to solve these problems without having to resort to additional components or having particularly complex control systems.
  • the present invention relates to a method containing the features listed in claim 1.
  • a vehicle may be a construction machine such as a bulldozer.
  • a vehicle is defined as any vehicle capable of performing vehicle displacement.
  • Figure 1 shows a hydraulic diagram of a traction system for a working machine with respect to which an adjustment method may be used according to an embodiment of the present invention. Only the components essential to the invention are described.
  • the system has a casing 1 on which two working connections are formed to which a working line of a closed circuit, for example a hydraulic motor 3 such as that shown in the figure, is connected respectively.
  • a drive system for a mobile working machine (not shown), such as a bulldozer, is formed.
  • the axial piston pump 12 is made with an oblique disc 2 (also referred to more generally as an oblique element) whose angle of oscillation ⁇ pmp can be set by means of an adjusting unit 4, so as to go to adjust the displacement of the pump itself.
  • a double-action regulating cylinder 6 is used for this purpose, which has a first chamber 8 1 of the regulating pressure and a second chamber 8 2 of the regulating pressure acting in the opposite direction to the first chamber.
  • a first control pressure p st1 acts in the first chamber of control pressure 8 1 in the direction of an increase in swing angle ⁇ pmp and thus in the direction of an increase in pump displacement 12.
  • a second control pressure p st2 in the second chamber 8 2 acts in the direction of a reduction in the oscillation angle ⁇ pmp and thus in the direction of a reduction in pump displacement 12.
  • a difference in control pressure ⁇ pst can be defined given by the difference of the first and second control pressures p st1 , p st2 , this difference in control pressure ⁇ pst by definition always acts in the direction of an increase in the oscillation angle ⁇ pmp and thus in the displacement itself.
  • Drive shaft 10 can be driven by a diesel engine (not shown) or alternatively also by an electric motor and rotates with a variable number of revolutions. This number of revolutions acts together with the control pressure difference in the direction of an increase in the oscillation angle ⁇ pmp .
  • the axial piston pump 12 in the case of forward travel, feeds a high pressure line HD which allows it to supply a certain pressure to the hydraulic motor 3.
  • the high pressure HD which is also referred to as working pressure, acts in the direction of a reduction in the oscillation angle ⁇ pmp .
  • the two control pressures are controlled by two pressure reducing valves 18 1 , 18 2 . These respectively have an electric magnet a, b, which via a respective electrical line 20 1 , 20 2 is connected with the electronic control unit 16.
  • the two pressure reduction valves 18 1 , 18 2 are designed so that the respective control pressure p st1 , p st2 is proportional to the respective current intensity (20 1 , 20 2 ).
  • the two pressure reducing valves 18 1 , 18 2 are supplied on the inlet side via a supply pressure line 22 from supply pump 14.
  • the hydrostatic traction system comprises a drive motor and hydraulic pump 12, the rotation of which is ensured by said drive motor, and at least one hydraulic motor 3 connected in a closed circuit to said hydraulic pump 12, wherein said hydraulic pump 12 has the adjustment unit 16 for adjusting the displacement of said hydraulic pump 12, wherein said displacement is adjustable by adjusting the angle of inclination ⁇ pmp of the inclined element 2.
  • a desired speed v T of said mobile working machine takes place.
  • This desired speed may be, for example, the speed requested by a user via a foot pedal or even via a joystick.
  • a second step 100 the determination of a minimum number of revolutions n MIN of said drive motor capable of enabling said mobile work machine to reach said desired speed v T takes place.
  • Said determination of said minimum number of revolutions n MIN may be performed substantially by two alternative methods. As will be clear from the description in both methods the minimum number of revolutions is calculated.
  • the desired value is the result of a mathematical operation such as using a function or a direct calculation. Therefore, in light of the two examples described, it is clear that “calculate” does not identify merely the mathematical calculation but the fact that on the basis of an input variable that desired value is derived.
  • a flow balance equation and a hydrostatic drive system efficiency criterion can be used. This is because in order to achieve a given speed of the working machine, there are infinite combinations of values of the hydrostatic transmission ratio and the speed of the traction motor, which can be determined by means of a flow balancing equation. Therefore, the "ideal" condition among the possible ones can be chosen on the basis of an efficiency criterion. Basically, on the basis of the desired speed v T a simulation takes place, the result of which is the value of the number of revolutions capable of allowing that final speed to be reached under an ideal condition.
  • the determination of the minimum number of revolutions n MIN takes place by means of a function describing for each desired speed v T of said mobile work machine at least one value of said minimum number of revolutions n MIN of said drive motor capable of allowing to reach said desired speed v T , at a predefined condition of said mobile work machine.
  • Said predefined condition preferably corresponds to the translation of said mobile work machine along a flat surface.
  • an initial test speed is set that must be maintained by said mobile working machine during an initial test. It starts with a fairly high number of revolutions value so as to ensure that the first speed is reached. At the same time the number of revolutions of said drive motor is progressively decreased thus going to change the gear ratio accordingly, while keeping, however, both the speed and the predefined condition (e.g., movement on a flat or inclined surface) constant.
  • the efficiency of said hydrostatic drive system is detected, i.e., the ratio between the output power supplied (which remains constant since the speed is constant) and the input power supplied by the drive motor.
  • This method is repeated equally for at least a second test speed, obtaining a second number of revolutions of said drive motor at which said efficiency was detected.
  • the function is then derived by interpolating the detected values of said number of revolutions for said at least two test speeds. It is clear that, in order to improve the accuracy of said function it will be particularly advantageous to have a number of test speeds greater than two so as to have a function that better reflects the behavior at the desired speed range v T (e.g., equal to three, four or five test speeds)
  • a correction value n off of said minimum speed n MIN of said drive motor is calculated.
  • said correction value n off is constantly filtered 102 before being used to adjust said drive motor.
  • Said correction value n off is preferably added 103 to said minimum number of revolutions n MIN obtaining a corrected minimum number of revolutions nT.
  • Said drive motor is then preferably adjusted by taking into consideration said minimum corrected number of revolutions n T .
  • the drive motor is further adjusted by taking into consideration a minimum speed n WO of said drive motor required by a work function of said mobile work machine.
  • step 104 the maximum value between the minimum required speed nwo, for example due to the speed required for moving a mechanical arm by means of a hydrostatic cylinder, and minimum required speed n T will be taken.
  • the present invention also describes a computational unit adapted to perform a method according to any of the forms of embodiments presented above.
  • the present description includes a computer program that induces a computing unit to perform a method as described in the present invention.
  • a readable storage medium comprising the computer program stored thereon described above is also described.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Control Of Fluid Gearings (AREA)
EP23183000.1A 2022-07-08 2023-07-03 Verfahren zur einstellung eines hydrostatischen fahrsystems Pending EP4303438A1 (de)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT102022000014464A IT202200014464A1 (it) 2022-07-08 2022-07-08 Metodo di regolazione di un sistema di trazione idrostatico

Publications (1)

Publication Number Publication Date
EP4303438A1 true EP4303438A1 (de) 2024-01-10

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP23183000.1A Pending EP4303438A1 (de) 2022-07-08 2023-07-03 Verfahren zur einstellung eines hydrostatischen fahrsystems

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EP (1) EP4303438A1 (de)
IT (1) IT202200014464A1 (de)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0908564A2 (de) * 1997-10-08 1999-04-14 Hitachi Construction Machinery Co., Ltd. Steuersystem für die Antriebsmaschine und die hydraulische Pumpe einer Baumaschine
US20060113140A1 (en) * 2003-08-01 2006-06-01 Tsuyoshi Nakamura Traveling hydraulic working machine
US20140180550A1 (en) * 2012-12-21 2014-06-26 Cnh America Llc Load control for a machine with a dual path electronically controlled hydrostatic transmission
US20200003301A1 (en) * 2018-06-29 2020-01-02 Robert Bosch Gmbh Hydrostatic Travel Drive and Method for Controlling the Hydrostatic Travel Drive
US20200332891A1 (en) * 2019-04-16 2020-10-22 Robert Bosch Gmbh Axial Piston Pump for a Hydrostatic Propulsion Drive, Hydrostatic Propulsion Drive with the Axial Piston Pump, and Method for Control
US11002266B2 (en) * 2017-08-03 2021-05-11 Voith Patent Gmbh Method for regulating the output pressure of a hydraulic drive system, use of the method and hydraulic drive system
US20210382444A1 (en) * 2020-06-03 2021-12-09 Robert Bosch Gmbh Method for teaching the control function of hydrostatic motors when in drive mode

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0908564A2 (de) * 1997-10-08 1999-04-14 Hitachi Construction Machinery Co., Ltd. Steuersystem für die Antriebsmaschine und die hydraulische Pumpe einer Baumaschine
US20060113140A1 (en) * 2003-08-01 2006-06-01 Tsuyoshi Nakamura Traveling hydraulic working machine
US20140180550A1 (en) * 2012-12-21 2014-06-26 Cnh America Llc Load control for a machine with a dual path electronically controlled hydrostatic transmission
US11002266B2 (en) * 2017-08-03 2021-05-11 Voith Patent Gmbh Method for regulating the output pressure of a hydraulic drive system, use of the method and hydraulic drive system
US20200003301A1 (en) * 2018-06-29 2020-01-02 Robert Bosch Gmbh Hydrostatic Travel Drive and Method for Controlling the Hydrostatic Travel Drive
US20200332891A1 (en) * 2019-04-16 2020-10-22 Robert Bosch Gmbh Axial Piston Pump for a Hydrostatic Propulsion Drive, Hydrostatic Propulsion Drive with the Axial Piston Pump, and Method for Control
US20210382444A1 (en) * 2020-06-03 2021-12-09 Robert Bosch Gmbh Method for teaching the control function of hydrostatic motors when in drive mode

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Publication number Publication date
IT202200014464A1 (it) 2024-01-08

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