EP0610940B1 - Regulator for a variable displacement pump - Google Patents

Regulator for a variable displacement pump Download PDF

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Publication number
EP0610940B1
EP0610940B1 EP94102088A EP94102088A EP0610940B1 EP 0610940 B1 EP0610940 B1 EP 0610940B1 EP 94102088 A EP94102088 A EP 94102088A EP 94102088 A EP94102088 A EP 94102088A EP 0610940 B1 EP0610940 B1 EP 0610940B1
Authority
EP
European Patent Office
Prior art keywords
piston
servo
pump
variable displacement
working pressure
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP94102088A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0610940A1 (en
Inventor
Young Guk Kim
Tae Jong Kim
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.)
HD Hyundai Infracore Co Ltd
Original Assignee
Daewoo Heavy Industries Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Daewoo Heavy Industries Ltd filed Critical Daewoo Heavy Industries Ltd
Publication of EP0610940A1 publication Critical patent/EP0610940A1/en
Application granted granted Critical
Publication of EP0610940B1 publication Critical patent/EP0610940B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • 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
    • F04B49/002—Hydraulic systems to change the pump delivery
    • 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
    • F04B1/14—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 having stationary cylinders
    • 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
    • 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
    • F04B49/08—Regulating by delivery pressure
    • 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
    • F04B2201/1204—Position of a rotating inclined plate

Definitions

  • the present invention relates to a regulator for a variable displacement pump; and, more particularly, to a regulator provided with a hydraulic servo controller capable of controlling the displacement volume of the pump and accomplishing a feedback function depending upon the working pressure from the pump, an effective spring force and a pilot pressure to achieve a stable flow rate and reduce energy losses.
  • a conventional variable displacement pump comprises a regulator which employs a device for controlling the angle of a swash plate therein.
  • a regulator comprising: a valve body; means for controlling the angle of a swash plate; a directional changeover valve defining a position for supplying a working pressure to a first chamber, a position for sealing the first chamber and a position for discharging the load pressure from the first chamber; a feedback lever for connecting an end of the changeover valve with a servo-piston of the control means; a first pilot spool movable by the working pressure from the pump for controlling the horsepower thereof; a second pilot spool movable by the pilot pressure, wherein a reservoir pressure is included, for controlling the flow rate of the pump; and a linkage mechanism for selectively applying one of the first and the second pilot spools to the feedback lever to reduce the discharge flow rate thereof.
  • the linkage mechanism of the regulator complicates the overall structure and construction thereof. Further, since the flow rate of the pump is likely to be affected by a variation in the reservoir pressure of the hydraulic system during the flow rate control, it is difficult to achieve and maintain a predetermined target flow rate. In addition, the regulator is handicapped by the absence of a flow rate cutoff control and a flow rate cutoff release control, thereby causing an energy loss due to its inability to prevent an unnecessary discharge flow.
  • variable displacement pump incorporating therein a regulator for controlling the flow rate of a fluid therein by means of varying the angle of a swash plate
  • a pump for producing a flow of the fluid a valve body in fluid-communication with the pump; a servo-piston pivotally mounted to the swash plate and provided with two portions, each having a different diameter, which are movable along a first and a second chambers formed within the valve body; a multi-stage piston movable along a first and a second piston compartments in the valve body by a working pressure from the pump; a control rod movable along an axis of the servo-piston and having a servo-spool for changing the direction of the flow; a servo-sleeve in fluid-communication with the servo spool for defining a neutral position, a position for supplying the working pressure of the second chamber and a position for discharging the
  • a regulator 10 in accordance with the present invention.
  • a pair of variable displacement pumps Pd 1 and Pd 2 driven by an engine 12 produce a flow rate for the hydraulic pumps Pd 1 , Pd 2, which is controlled by means of varying the angle of a swash plate 14.
  • a gear pump Pg is also driven by the engine 12 to deliver a pilot pressure to the regulator 10.
  • a valve body 11 is installed to be fluid communicable with the pumps Pd 1 ,Pd 2 and Pg.
  • the swash plate 14 is pivotally mounted to a servo-piston 16 at its one portion of the periphery thereof by a connecting rod 18 fixed to the servo-piston 16.
  • the servo-piston 16 has two portions: i.e., portion a having a relatively small diameter and portion b having a relatively large diameter, each of which is slidably movable along a first chamber 20 and a second chamber 22 formed within the valve body 11.
  • the first chamber 20 is fluid communicable with the pump Pd 1 while the second chamber 22 is fluid communicable with a reservoir 24 through a cutoff spool 26 and a servo-spool 28 having a changeover recess 30.
  • a servo-sleeve 34 has three holes 31, 32, 33 for defining a neutral position as shown in Fig.
  • a control rod 36 is connected to the servo-piston 16 by a first and a second springs 38, 40 capable of transmitting to the servo spool 28 the difference between the forces acted on the control rod 36 and the servo-piston 16, thereby changing or adjusting the hole position of the servo-sleeve 34.
  • a multi-stage piston 42 in contact with the control rod 36 is slidably located in a first and a second piston compartments 44, 46, having a plurality of stages, each of which has a different diameter. As shown in Fig. 2, the control rod 36, the servo-piston 16, the multi-stage piston 42, and the springs 38,40 and 66 have a coaxial relationship with one another.
  • the working pressure from the pumps Pd 1 , Pd 2 is supplied to the first and the second piston compartments 44, 46 through pressure lines 48, 50, and a pilot pressure is applied to a pilot chamber 52, a drain chamber 54 and a third piston chamber 56 through pilot lines 58, 60 from a control valve 64 and a line 62 through a reducing valve 76 from the gear pump Pg.
  • the gear pump Pg is installed to maintain a constant initial pressure of the hydraulic circuitry to thereby prevent a delayed response time of the regulator 10 at a low working pressure.
  • the working pressure initially supplied to the first chamber 20 is the higher one of the working pressure of the pump Pd 1 and the gear pump Pg.
  • the hydraulically pressurized area of the servo-piston 16 located in the second chamber 22 is broader than that located in the first chamber 20, the movement to the left side of the servo-piston 16 decreases the angle of the swash plate 14 to thereby reduce the dicharge flow rate from the pumps and tends to urge the outer spring 38 against the control rod 36. Consequently, the control rod 36 is moved to the left to reduce the area, through which the flow is passed, formed by the relative position of the holes 31,32 and 33 of the servo-sleeve 34 and the recess 30 of the servo-spool 28, thereby decreasing the working pressure supplied to the second chamber 22.
  • the working pressure supplied to a first cutoff piston compartment 70 overcomes the resilient force of a fourth spring 72 so that the cutoff spool 26 is moved to directly supply the working pressure into the second chamber 22.
  • the servo-piston 16 is moved to reduce the angle of the swash plate 14, thereby reducing the discharge flow rate of the pumps up to its minimum value, i.e., point D shown in Fig. 3.
  • the flow rate cutoff control therefore minimizes the energy loss by reducing the discharge flow rate up to the minimum value.
  • variable displacement pump requires the flow rate more than that of the section C-D
  • a pilot pressure Pcf from the exterior(shown in dotted lines) is supplied into a second cutoff piston compartments 74.
  • the recovering force of the fourth spring 72 added to the pilot pressure Pcf in the second cutoff piston compartment 74 defeats the working pressure in the first cutoff piston compartment 70 to ensure that the second chamber 22 is communicated with the reservoir 24 through the hole 31 of the servo spool 28 via the cut off spool 26, although the working pressure higher than the point C is supplied therein.
  • the servo-piston 16 is moved to increase the discharge flow rate of the pumps Pd1 and Pd2 more than their minimum flow rate, thereby releasing the flow rate cutoff control.
  • Fig. 4 illustrates a graph showing the relationship between the pilot pressure and the flow rate.
  • the pilot pressure Pc from the control valve 64 is directly supplied to the pilot chamber 52 through the line 58 and the pilot pressure Pcf is supplied to the drain chamber 54 via an orifice 65 through a line 60.
  • the pilot pressure Pc has a higher value than that of the pilot pressure Pcf.
  • the flow rate control is accomplished by the pressure difference ⁇ P between the pressure Pc in the pilot chamber 52 and the pressure Pcd of the drain chamber 54 as shown in Fig. 4, wherein its operational process is similar that of Fig. 3.
  • FIG. 3 there is shown another horsepower control diagram, i.e., line A''-B''-C'', accomplished by a pilot pressure Pps from the gear pump Pg.
  • the pilot pressure Pps from is supplied into the third piston compartment 56 to increase the working pressure applied to the multi-stage piston 42.
  • the resultant force acted on the multistage piston 42 urges the control rod 36 so that the discharge flow rate begins to be reduced to control the horsepower constantly along the line A''-B''-C'' shown in Fig. 3, when the working pressure is lower than the point A'', wherein its operational process is similar to that of the line A-B-C shown in Fig. 3.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Control Of Positive-Displacement Pumps (AREA)
  • Reciprocating Pumps (AREA)
  • Rotary Pumps (AREA)
EP94102088A 1993-02-11 1994-02-10 Regulator for a variable displacement pump Expired - Lifetime EP0610940B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR1019930001848A KR950013009B1 (ko) 1993-02-11 1993-02-11 가변용량형 유압피스톤 펌프의 유량제어장치
KR931848 1993-02-11

Publications (2)

Publication Number Publication Date
EP0610940A1 EP0610940A1 (en) 1994-08-17
EP0610940B1 true EP0610940B1 (en) 1996-09-25

Family

ID=19350668

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94102088A Expired - Lifetime EP0610940B1 (en) 1993-02-11 1994-02-10 Regulator for a variable displacement pump

Country Status (4)

Country Link
EP (1) EP0610940B1 (zh)
KR (1) KR950013009B1 (zh)
CN (1) CN1033052C (zh)
DE (1) DE69400583T2 (zh)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5567123A (en) * 1995-09-12 1996-10-22 Caterpillar Inc. Pump displacement control for a variable displacement pump
DE19735110B4 (de) * 1997-08-13 2004-09-16 Brueninghaus Hydromatik Gmbh Regelvorrichtung mit Druckmittler
US6623247B2 (en) * 2001-05-16 2003-09-23 Caterpillar Inc Method and apparatus for controlling a variable displacement hydraulic pump
US6848254B2 (en) 2003-06-30 2005-02-01 Caterpillar Inc. Method and apparatus for controlling a hydraulic motor
DE102010020004A1 (de) * 2010-03-05 2011-09-08 Robert Bosch Gmbh Regelungsvorrichtung und Verfahren zur Regelung eines Drehmoments einer Triebwelle einer hydrostatischen Maschine
DE102011120082A1 (de) * 2011-12-05 2013-06-06 Man Truck & Bus Ag Einstellvorrichtung, insbesondere für Kraftfahrzeuge
CN103511369A (zh) * 2013-09-11 2014-01-15 中航力源液压股份有限公司 多档功率控制变量柱塞泵
CH714321A1 (de) * 2017-11-11 2019-05-15 Liebherr Machines Bulle Sa Verstellvorrichtung für eine Axialkolbenmaschine.
CN108591151B (zh) * 2018-02-05 2023-11-21 江苏恒立液压科技有限公司 液压轴向柱塞泵功率控制及正流量控制机构

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3834836A (en) * 1973-03-01 1974-09-10 Caterpillar Tractor Co Override control for a variable displacement pump
US4381646A (en) * 1980-09-12 1983-05-03 Caterpillar Tractor Co. Torque and high pressure limiting control for variable displacement pumps
KR950007252B1 (ko) * 1991-11-30 1995-07-07 삼성중공업주식회사 가변용량형 유압펌프의 제어장치
KR950003064B1 (ko) * 1992-05-30 1995-03-30 삼성중공업 주식회사 가변용량형 유압펌프의 제어장치

Also Published As

Publication number Publication date
CN1094794A (zh) 1994-11-09
DE69400583T2 (de) 1997-02-06
DE69400583D1 (de) 1996-10-31
EP0610940A1 (en) 1994-08-17
KR950013009B1 (ko) 1995-10-24
KR940019991A (ko) 1994-09-15
CN1033052C (zh) 1996-10-16

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