US3738779A - Variable displacement pump having pressure compensation control means - Google Patents

Variable displacement pump having pressure compensation control means Download PDF

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Publication number
US3738779A
US3738779A US00157157A US3738779DA US3738779A US 3738779 A US3738779 A US 3738779A US 00157157 A US00157157 A US 00157157A US 3738779D A US3738779D A US 3738779DA US 3738779 A US3738779 A US 3738779A
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United States
Prior art keywords
cartridge
pump
swash plate
pressure
chamber
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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
US00157157A
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English (en)
Inventor
A Hein
W Ruseff
G Tribley
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.)
Caterpillar Inc
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Caterpillar Tractor Co
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Filing date
Publication date
Application filed by Caterpillar Tractor Co filed Critical Caterpillar Tractor Co
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Assigned to CATERPILLAR INC., A CORP. OF DE. reassignment CATERPILLAR INC., A CORP. OF DE. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: CATERPILLAR TRACTOR CO., A CORP. OF CALIF.
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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

Definitions

  • This invention is directed to a variable displacement pump of the type having a plurality of rotatable, axiallyaligned pistons guided by a nonrotatable, tiltable swash plate which enables adjustment of pump displacement by the operation of pressure compensator control means.
  • constant displacement pumps are'widely used as a source of fluid pressue to power hydraulic circuitsin many applications.
  • constant displacement pumps are used to power hydraulic implement circuits on heavy construction equipment such as tractors, etc.
  • this application there is no provision for returning pump flow to tank when the implement control-valves are in a neutral position unless an open-center system is used.
  • an additional amount of engine horsepower is needed to drive the constant delivery pump at maximum-relief valve pressure even when no actuating fluid is demanded by the system.- This, in turn, results in an undesirable, excessive amount of heat generation in the hydraulic system.
  • variable displacement pump having pressure compensator control means operable to control pump displacement in response to system pressure.
  • FIG. 1' is a top plan view of a hydraulic, variable displacement pump having hydraulic pressure compensator control means installed therein;
  • FIG. 1 there is shown generally at 10 a top view of a variable displacement pump containing two vertical bores 12, 14 which are offset from the pump center line. These bores contain the mechanisms for changing the pump displacement, as will be hereinafter described.
  • the pump body consists of a head 16 seated upon a housing 18. Contained within the head is an inlet passage 20 and an outlet passage 22.
  • variable displacement pump 10 taken along line lI-II in FIG. 1.
  • the pistons are guided by a slipper pad 28 rotatably, slidably mounted on support means in the form of a nonrotatable but tiltable swash plate 30.
  • the swash plate is pivotable about a transverse axis by means of transverse pivot pins (not shown) retained in transverse bores (not shown) in the sides of housing 18.
  • the angle of tilt of the swash plate 30 with respect to the axial direction of the bores 26 determines thev amount of stroke or displacement of the pistons 32 within their respective bores 26 in the conventional manner. Since slipper pad 28 is ball-and-socket-joint connected to pistons 32 which, in turn, ride on surface 34 of the swash plate, it can be seen that if the swash plate were rotated clockwise about its pivot point from the position shown, the reciprocating action of the pistons in their respective bores would be minimized. Thus, a minimum displacement of fluid would occur through outlet passage 22 by way'of kidney port 36.
  • a pilot line 38 will be open to tank.
  • the swash plate 30 Prior to pump cylinder barrel rotation, the swash plate 30 is swivelled as shown against maximum displacement stop 40 by means of a piston 42 which is biased by a spring 44 which, in turn, reacts against a housing 46 of cartridge assembly 48.
  • a flange 50 on cartridge assembly 48 securely locates the assembly between the pump head 16 and pump housing 18. The entire assembly is secured in place within the pump body by means of a nut 52 which abuts against the top surface of head 16.
  • Fluid under pressure in passage 94 is directed to a chamber 102 where it works against a piston 104.
  • the force of the pressure acting on piston 104 will cause the piston to move downwardly.
  • the piston Since the piston is in contact with an arm extension 106 of swash plate 30, the swash plate will be swivelled in a clockwise direction toward its minimum displacement position. This minimum displacement position would be achieved when the extension 106 contacts adjustable minimum displacement stop 108.
  • This clockwise rotation of the swash plate 30 will occur against the biasing force of spring, piston combination 44, 42 which is acting upon the opposite arm extension 110 of the swash plate.
  • the position of the extension 106 against adjustable stop 108 corresponds to point A in the graph of FIG. 3. At this minimum displacement position, pump flow and pressure will be at a minimum, which will result in less horsepower loss and less heat generation in the system.
  • line 38 When one or more of the control valves on the machine are activated, line 38 will be blocked from tank by means (not shown) such that the pressures in chambers 58 and will equalize and spool 60 will be moved downwardly by the influence of biasing spring 76 to the position shown in FIG. 2. In this position, system pressure is directed to passage 66, a passage 112 transversely intersecting passage 66, annulus 80, passage 84, and then into chamber 82. Since the area of piston 42 in chamber 82 is greater than the area of piston 104 in chamber 102, piston 42 will push downwardly on the swash plate extension until it is stopped at the maximum displacement position by stop 40.
  • pump rotation will be in one direction due to the fact that the swash plate can be swivelled only in a clockwise direction. Therefore, when pump flow direction is to be changed, the capsule or cartridge assemblies 98 and 122 must also be interchanged along with stops 40 and 108 in order that the inlet and outlet ports will remain the same. This interchanging may be easily accomplished with the device of the instant invention, since cartridge assemblies 98 and 122 have the same exterior circumferential dimension as well as being generally cylindrical.
  • annulus 74 is located at the same vertical level in the head as annulus 124 whereby interchanging of assemblies 98 and 122 results in passage 72 in cartridge assembly 48 being in fluid communication with tank line 38 by way of the annuli and passages 126, 128 and chamber 130. Access to the chamber 130 may be conveniently had by means of plug 132 which is threadably secured in the top surface of head 16.
  • annuli 62 and 90 are located at the same vertical level in the head. Passage 134 and line 136 leading to tank are provided so as to correspond with their counterparts numbered 88, 86. Obviously, when the assemblies are located as shown in FIG. 2, cartridge 96 obturates passage 134 and annulus 124 whereby these elements are unused.
  • head 16 is removed from housing 18 by detaching fastening means (not shown). Threaded plug 138 is unscrewed from its mating opening in the end of cartridge 96 and nut 52 is similarly unscrewed from the threaded end of assembly 48. The respective cartridges are interchanged, plug 138 and nut 52 resecured, and the head 16 resecured to housing 18. As aforementioned, an intermediate stepof exchnaging stops 40 and 108 would also be accomplished.'
  • a variable displacement axial piston pump of the type having a housing means containing an inlet port and a discharge port, a plurality of piston means and an angularly adjustable swash plate means for determining piston displacement and thereby the amount of fluid discharged from the pump, resilient means in a first cartridge assembly means biasing the swash plate means to its maximum discharge position whereby a maximum of fluid is displaced by-the pump, and pressure responsive means in a second cartridge assembly means for shifting said swash plate means to its minimum discharge position in responseto a pressure such as from a hydraulic system, reversing means whereby interchanging said first cartridge assembly means with said second cartridge assembly means causes the pump flow direction to be reversed, said reversing means comprising a pair of stop means, one of which is associated with the swash plate adjacent said first cartridge assembly means and the other of which is associated with the other of said cartridge assembly means, said stop means being interchangeable, one with the other, said first cartridge assembly means comprising a first generally cylindrical cartridge member in a first bore in said housing means

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Reciprocating Pumps (AREA)
US00157157A 1971-06-28 1971-06-28 Variable displacement pump having pressure compensation control means Expired - Lifetime US3738779A (en)

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US15715771A 1971-06-28 1971-06-28

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US (1) US3738779A (fr)
BE (1) BE801249A (fr)

Cited By (20)

* 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
US3872775A (en) * 1973-09-25 1975-03-25 Robert Cecil Clerk Swash-plate bearings for axial piston pumps or motors
US3941513A (en) * 1974-09-05 1976-03-02 Parker-Hannifin Corporation Variable displacement pump control assembly
US3945764A (en) * 1974-09-05 1976-03-23 Parker-Hannifin Corporation Variable displacement pump control assembly
US3977437A (en) * 1973-06-22 1976-08-31 Robert Cecil Clerk Control systems for hydraulic pumps and motors
US4028010A (en) * 1974-06-21 1977-06-07 Caterpillar Tractor Co. Reversible, variable-displacement piston pump with positioner means for automatic return to zero displacement
US4212596A (en) * 1978-02-23 1980-07-15 Caterpillar Tractor Co. Pressurized fluid supply system
US4248574A (en) * 1978-09-22 1981-02-03 Kabushiki Kaisha Komatsu Seisakusho Hydraulic control system for variable displacement pumps
US4248573A (en) * 1978-09-22 1981-02-03 Kabushiki Kaisha Komatsu Seisakusho Hydraulic control system for variable displacement pump
US4275996A (en) * 1978-06-13 1981-06-30 Danfoss A/S Control device for adjustable fluid pumps or motors
US6016691A (en) * 1998-02-25 2000-01-25 Siemens Canada Ltd. Calibrated toggle lever of leak detection module pump
US6374722B1 (en) 2000-10-26 2002-04-23 Caterpillar Inc. Apparatus and method for controlling a discharge pressure of a variable displacement hydraulic pump
US6468046B1 (en) 2000-09-18 2002-10-22 Caterpillar Inc Apparatus and method for controlling a discharge pressure of a variable displacement hydraulic pump
US6715693B1 (en) 2000-02-15 2004-04-06 Caterpillar Inc Thin film coating for fuel injector components
US20040251312A1 (en) * 1998-09-21 2004-12-16 Caterpillar Inc. Coatings for use in fuel injector components
US20040261407A1 (en) * 2003-06-30 2004-12-30 Hongliu Du Method and apparatus for controlling a hydraulic motor
US20050238501A1 (en) * 2004-04-26 2005-10-27 Brailovskiy Aleksandr M Revolving yoke load-sensitive displacement-varying mechanism for axial piston hydraulic pump
CN110500253A (zh) * 2018-05-17 2019-11-26 纳博特斯克有限公司 液压泵
US20230122543A1 (en) * 2020-05-26 2023-04-20 Kyb Corporation Fluid pressure rotating machine
US20230204017A1 (en) * 2020-05-26 2023-06-29 Kyb Corporation Fluid pressure rotating machine

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2291424A (en) * 1940-11-13 1942-07-28 Pump Engineering Service Corp Pump with by-pass valve
US2696189A (en) * 1951-03-20 1954-12-07 Denison Eng Co Volume indicator for hydraulic pumps
US3221660A (en) * 1963-08-20 1965-12-07 Amato Michael A D Automatic control for variable displacement pump

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2291424A (en) * 1940-11-13 1942-07-28 Pump Engineering Service Corp Pump with by-pass valve
US2696189A (en) * 1951-03-20 1954-12-07 Denison Eng Co Volume indicator for hydraulic pumps
US3221660A (en) * 1963-08-20 1965-12-07 Amato Michael A D Automatic control for variable displacement pump

Cited By (32)

* 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
US3977437A (en) * 1973-06-22 1976-08-31 Robert Cecil Clerk Control systems for hydraulic pumps and motors
US3872775A (en) * 1973-09-25 1975-03-25 Robert Cecil Clerk Swash-plate bearings for axial piston pumps or motors
US4028010A (en) * 1974-06-21 1977-06-07 Caterpillar Tractor Co. Reversible, variable-displacement piston pump with positioner means for automatic return to zero displacement
US3941513A (en) * 1974-09-05 1976-03-02 Parker-Hannifin Corporation Variable displacement pump control assembly
US3945764A (en) * 1974-09-05 1976-03-23 Parker-Hannifin Corporation Variable displacement pump control assembly
FR2284050A1 (fr) * 1974-09-05 1976-04-02 Parker Hannifin Corp Ensemble de commande de pompe a debit variable
US4212596A (en) * 1978-02-23 1980-07-15 Caterpillar Tractor Co. Pressurized fluid supply system
US4275996A (en) * 1978-06-13 1981-06-30 Danfoss A/S Control device for adjustable fluid pumps or motors
US4248574A (en) * 1978-09-22 1981-02-03 Kabushiki Kaisha Komatsu Seisakusho Hydraulic control system for variable displacement pumps
US4248573A (en) * 1978-09-22 1981-02-03 Kabushiki Kaisha Komatsu Seisakusho Hydraulic control system for variable displacement pump
US6016691A (en) * 1998-02-25 2000-01-25 Siemens Canada Ltd. Calibrated toggle lever of leak detection module pump
US20040251312A1 (en) * 1998-09-21 2004-12-16 Caterpillar Inc. Coatings for use in fuel injector components
US20080179430A1 (en) * 1998-09-21 2008-07-31 Caterpillar Inc. Coatings for use in fuel injector components
US7942343B2 (en) 1998-09-21 2011-05-17 Caterpillar Inc. Coatings for use in fuel injector components
US7484672B2 (en) 1998-09-21 2009-02-03 Caterpillar Inc. Coatings for use in fuel injector components
US6715693B1 (en) 2000-02-15 2004-04-06 Caterpillar Inc Thin film coating for fuel injector components
US20040195386A1 (en) * 2000-02-15 2004-10-07 Caterpillar Inc. Thin film coatings for fuel injector components
US7021557B2 (en) 2000-02-15 2006-04-04 Caterpillar Inc. Thin film coatings for fuel injector components
US20060151627A1 (en) * 2000-02-15 2006-07-13 Caterpillar Inc. Thin film coating for fuel injector components
US6468046B1 (en) 2000-09-18 2002-10-22 Caterpillar Inc Apparatus and method for controlling a discharge pressure of a variable displacement hydraulic pump
US6374722B1 (en) 2000-10-26 2002-04-23 Caterpillar Inc. Apparatus and method for controlling a discharge pressure of a variable displacement hydraulic pump
US20040261407A1 (en) * 2003-06-30 2004-12-30 Hongliu Du Method and apparatus for controlling a hydraulic motor
US6848254B2 (en) 2003-06-30 2005-02-01 Caterpillar Inc. Method and apparatus for controlling a hydraulic motor
US20050238501A1 (en) * 2004-04-26 2005-10-27 Brailovskiy Aleksandr M Revolving yoke load-sensitive displacement-varying mechanism for axial piston hydraulic pump
CN110500253A (zh) * 2018-05-17 2019-11-26 纳博特斯克有限公司 液压泵
US11603830B2 (en) * 2018-05-17 2023-03-14 Nabtesco Corporation Hydraulic pump with swash plate tilt control
US12540605B2 (en) * 2018-05-17 2026-02-03 Nabtesco Corporation Hydraulic pump with swash plate tilt control
US20230122543A1 (en) * 2020-05-26 2023-04-20 Kyb Corporation Fluid pressure rotating machine
US20230204017A1 (en) * 2020-05-26 2023-06-29 Kyb Corporation Fluid pressure rotating machine
US11767832B2 (en) * 2020-05-26 2023-09-26 Kyb Corporation Fluid pressure rotating machine
US11952988B2 (en) * 2020-05-26 2024-04-09 Kyb Corporation Fluid pressure rotating machine

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Publication number Publication date
BE801249A (fr) 1973-10-15

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Legal Events

Date Code Title Description
AS Assignment

Owner name: CATERPILLAR INC., A CORP. OF DE.,ILLINOIS

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:CATERPILLAR TRACTOR CO., A CORP. OF CALIF.;REEL/FRAME:004669/0905

Effective date: 19860515

Owner name: CATERPILLAR INC., 100 N.E. ADAMS STREET, PEORIA, I

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:CATERPILLAR TRACTOR CO., A CORP. OF CALIF.;REEL/FRAME:004669/0905

Effective date: 19860515