US3633464A - Controlling system for positioning a swashplate of a multiple-piston rotary fluid pump or motor - Google Patents

Controlling system for positioning a swashplate of a multiple-piston rotary fluid pump or motor Download PDF

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Publication number
US3633464A
US3633464A US887515A US3633464DA US3633464A US 3633464 A US3633464 A US 3633464A US 887515 A US887515 A US 887515A US 3633464D A US3633464D A US 3633464DA US 3633464 A US3633464 A US 3633464A
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United States
Prior art keywords
swashplate
servo piston
manually operable
spool valve
single servo
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Expired - Lifetime
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US887515A
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English (en)
Inventor
Ryozo Aoyama
Akira Koiwai
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Komatsu Ltd
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Komatsu Ltd
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Publication date
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Publication of US3633464A publication Critical patent/US3633464A/en
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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
    • 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
    • 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

  • a controlling system for positioning a swashplate of a multiple-piston rotary fluid pump or motor comprising a servo piston, a changeover valve, an operating lever, and a link mechanism connecting the above three components one after another.
  • the changeover valve is slid intermediate the link mechanism so as to actuate the servo piston and vary the inclination of the swashplate.
  • the changeover valve is again slid to the neutral position.
  • the changeover valve serves to resist such variation.
  • This invention relates to improvements in a controlling system for positioning a swashplate of a multiple-piston rotary fluid pump or motor, that is, a variable displacement plunger pump, whereby a displacement thereof is varied.
  • the primary object of this invention is to provide a controlling system and a means therefor improved for overcoming the above defect.
  • Another object of this invention is to provide a controlling system of the class described, in which slight inclination of the swashplate to be derived from variation in load externally subjected to the pump and unbalanced moments by itself are not directly transmitted to other parts as excessive loads.
  • Still another object of this invention is to provide a controlling system of the class described, in which the servo piston is movable well in response to the theoretical output of the charging circuit.
  • a controlling system for positioning a swashplate of a multiple-piston rotary fluid pump or motor comprising a changeover valve adapted to be slid by an operating lever intermediate a link mechanism for actuating a servo piston by acting a pressured fluid medium thereto whereby the inclination of the swashplate is varied and the changeover valve is restored.
  • a multiple-piston rotary fluid pump or motor having a swashplate comprises, in combination, a servo piston, of which a piston rod is connected with a displaceable link at a pivot on an. end of the displaceable link, and adapted to control the inclination of the swashplate, a changeover valve having a spool, of which the valve rod is connected with the displaceable link at an intermediate point thereof, and adapted to control the servo piston, and an operating lever connected with the displaceable link at another pivot on the other end of the displaceable link for operating the changeover valve, the spool being adapted to be slid in the changeover valve along such a stroke when the firstnamed pivot is a fulcrum, as equal with another stroke along which the spool is adapted to be slid when the another pivot is another fulcrum.
  • any variation in the operating speed of the operating lever does not relate to the sliding speed of the servo piston and other balancing relations in pressure. It is possible to operate the operating lever at an optional speed without any unreasonableness in the link mechanism.
  • the changeover valve is operated at a speed in proportion to the operating speed of the controlling lever and yet the servo piston is not forcedly slid in accordance with the operation of the operating lever, and therefore, the servo piston is moved in response to a theoretical output of a charging circuit therefor without any influence of a sliding friction and an unbalance due to a back pressure.
  • FIG. I is a schematic view of a controlling means embodying this invention, in which a swashplate is in its neutral position;
  • FIG. 2 is an enlarged cross-sectional view of a friction clutch provided in the controlling means.
  • FIG. 3 is a schematic view similar to FIG. 1 but showing the swashplate in its inclined position.
  • a variable displacement plunger pump 1 l is provided with a swashplate l2 and with a neutral position restoring means 18. That is, the neutral position restoring means 18 is connected with an end 12a of the swashplate by a connecting link 30 for restoring the swashplate 12 into the neutral position.
  • the variable displacement plunger pump 11 is adapted to be driven by an engine and drive a fluid medium when the swashplate I2 is inclined. The inclination of the swashplate I2 is controlled by means of a servo piston 13 as shown in FIGS. 1 and 3.
  • the extent of the inclination of the swashplate is about 2.
  • the servo piston I3 is hydraulically driven by a fluid medium supplied from a fixed displacement pump 50 through a fluid duct 51.
  • the fixed displacement pump 50 is connected with a reservoir 53 through a filter 52.
  • the fluid duct 51 is branched to the reservoir 53 through a check valve 21.
  • a pin 13 rotatably mounted on the servo piston 13 is adapted to be slidably inserted in a slot 12b formed in the other end of the swashplate 12.
  • a changeover valve 14 having a spool is connected to the fluid duct 51 so as to change over the fluid duct 51 to direct the pressured fluid medium to either side of the servo piston 13.
  • a displaceable link 32 of which a pivot A on an end thereof is pivoted with a piston rod I3a by a link 31.
  • Another pivot C formed at an intermediate part of the displaceable link 32 is connected with an end of a valve rod of the spool of the changeover valve 14 intermediate a link 33.
  • the spool comprises three parts: a pair of parallel flow passages arranged in the left part thereof, a pair of neutral flow passages in the central part thereof, and a pair of crossflow passages in the right part thereof, as shown in FIGS. 1 and 3.
  • the other end of the valve rod of the spool of the changeover valve 14 is connected with a returning spring means 15, which serves for positioning the spool and facilitates the returning motion thereof.
  • the other end of the displaceable link 32 is provided with still another pivot B, on which the displaceable link 32 is connected with an operating lever 17 by a connecting link 34, a connecting lever 16 and a friction clutch comprisinga lining I9 and an initially coned disc spring 20 mounted on a rotary shaft 22, on which the connecting lever 16 and the operating lever 17 are fixed, as shown in FIG. 2.
  • variable displacement plunger pump 11 may serve for translating power to either direction.
  • the pivot B is displaced to another position B whereby the pivot A is indirectly displaced to another position A.
  • the rightward displacement of the servo piston 13 together with the pivot A causes a rightward displacement of the intermediate pivot C together with the valve rod and the spool of the changeover valve 14, because the pivot 13 in the position B is fixed thereto together with the connecting link 34 by virtue of the friction clutch and serves as a fulcrum on which the displaceable link 32 is swung in the clockwise direction in FIG. 1.
  • the swashplate 12 is operatively connected directly to a single servo piston means 13 so that the position of the single piston 13 will always correspond to a given angular position of the swashplate 12, as is apparent from a comparison of FIGS. 1 and 3, for example.
  • the single elongated control link means 32 is pivotally connected at one end to the single servo piston means and at its opposite end to a manually operable means formed by the levers 16 and 17 with the rod 22 interconnecting the latter.
  • the friction clutch assembly 19, 20 forms a retaining means for releasably retaining the manually operable means l6, 17, 22 in the position to which it is manually displaced.
  • the single elongated link means 32 is pivotally connected to the single spool valve means 14 which has the central neutral portion providing communication between the ends of the cylinder of the single servo piston means and the pair of end portions between which the central neutral portion is located, with one of these end portions providing for a flow of fluid to induce movement of the servo piston means in one direction and with the other of the end portions providing for a flow of fluid which will bring about movement of the servo piston means in the opposite direction.
  • the single elongated link means 32 will swing about its connection to the single servo piston means as a fulcrum, for displacing the single spool valve means in one direction or the other bringing about a corresponding change in the adjusted angle of the swashplate, and with the manually operable means retained in its set position by the retaining means formed by the friction clutch, the movement of the single servo piston means will again operate to restore the single spool valve means to its neutral position, thus providing a predetermined inclination for the swashplate.
  • the means 18 forms a spring means urging the swashplate back toward its neutral position, and it will be noted that this single spring means 18 is connected only to one part of the swashplate, at a portion of the latter opposed to the part of the swashplate which is connected to the single servo piston means. Also the spring means 15 forms a means which acts on the spool valve means to continuously urge the latter to return to its neutral position, so that the operation is enhanced by the spring means 15.
  • a tiltable swashplate tiltable about a predetermined axis
  • a single servo piston means operatively connected with said swashplate for tilting the latter about said axis
  • said single servo piston means including a single servo piston and a cylinder in which the latter is movable, so that the angular position of the swashplate will always correspond to a given position of the single servo piston in its cylinder
  • a single spool valve means having'a central neutral portion for providing communication between opposed ends of the cylinder of said single servo piston means and a pair of end portions one of which provides for movement of said single servo piston in one direction in said cylinder and the other of which provides for movement of said single servo piston in the opposite direction in said cylinder
  • manually operable means for manually setting the angular position of the swashplate
  • a single elongated link means having opposed ends respectively connected pivotally to said single servo piston and said manually oper

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Reciprocating Pumps (AREA)
  • Hydraulic Motors (AREA)
  • Control Of Fluid Gearings (AREA)
US887515A 1968-12-28 1969-12-23 Controlling system for positioning a swashplate of a multiple-piston rotary fluid pump or motor Expired - Lifetime US3633464A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP43096078A JPS4940242B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1968-12-28 1968-12-28

Publications (1)

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US3633464A true US3633464A (en) 1972-01-11

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US887515A Expired - Lifetime US3633464A (en) 1968-12-28 1969-12-23 Controlling system for positioning a swashplate of a multiple-piston rotary fluid pump or motor

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US (1) US3633464A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
JP (1) JPS4940242B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3945175A (en) * 1973-10-02 1976-03-23 International Harvester Company Variable speed feed roll drive mechanism for forage harvesters
US3995831A (en) * 1974-12-17 1976-12-07 The United States Of America As Represented By The Secretary Of The Army Force feedback controlled winch
US4381702A (en) * 1980-11-21 1983-05-03 Sundstrand Corporation Displacement control for a hydraulic pump or motor with failure override
USRE32403E (en) * 1970-08-03 1987-04-21 Dana Corporation Fluid device having interchangeable displacement control means
US20040112048A1 (en) * 2002-12-13 2004-06-17 Kuo-Hsiang Chien Stirling engine with variable stroke
US20100202900A1 (en) * 2007-08-07 2010-08-12 Robert Bosch Gmbh Hydrostatic machine having a control device having a return element for controlling a regulating valve

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US695061A (en) * 1901-09-07 1902-03-11 Janet Lang Valve-gear for controlling motors.
US1214496A (en) * 1915-02-25 1917-02-06 Frank H Armstrong Valve apparatus.
US2114445A (en) * 1936-01-21 1938-04-19 Waterbury Tool Co Power transmission
US2932948A (en) * 1959-03-19 1960-04-19 American Brake Shoe Co Horsepower limiting device
US3124008A (en) * 1964-03-10 firth etal
US3139006A (en) * 1961-09-11 1964-06-30 Budzich Tadeusz Constant speed hydraulic drive
US3187509A (en) * 1964-09-16 1965-06-08 Sundstrand Corp Hydrostatic transmission
US3434427A (en) * 1967-04-27 1969-03-25 Bendix Corp Control means for hydrostatic transmissions
US3463087A (en) * 1967-10-16 1969-08-26 Towmotor Corp Control response valve for hydrostatic transmission

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3124008A (en) * 1964-03-10 firth etal
US695061A (en) * 1901-09-07 1902-03-11 Janet Lang Valve-gear for controlling motors.
US1214496A (en) * 1915-02-25 1917-02-06 Frank H Armstrong Valve apparatus.
US2114445A (en) * 1936-01-21 1938-04-19 Waterbury Tool Co Power transmission
US2932948A (en) * 1959-03-19 1960-04-19 American Brake Shoe Co Horsepower limiting device
US3139006A (en) * 1961-09-11 1964-06-30 Budzich Tadeusz Constant speed hydraulic drive
US3187509A (en) * 1964-09-16 1965-06-08 Sundstrand Corp Hydrostatic transmission
US3434427A (en) * 1967-04-27 1969-03-25 Bendix Corp Control means for hydrostatic transmissions
US3463087A (en) * 1967-10-16 1969-08-26 Towmotor Corp Control response valve for hydrostatic transmission

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE32403E (en) * 1970-08-03 1987-04-21 Dana Corporation Fluid device having interchangeable displacement control means
US3945175A (en) * 1973-10-02 1976-03-23 International Harvester Company Variable speed feed roll drive mechanism for forage harvesters
US3995831A (en) * 1974-12-17 1976-12-07 The United States Of America As Represented By The Secretary Of The Army Force feedback controlled winch
US4381702A (en) * 1980-11-21 1983-05-03 Sundstrand Corporation Displacement control for a hydraulic pump or motor with failure override
US20040112048A1 (en) * 2002-12-13 2004-06-17 Kuo-Hsiang Chien Stirling engine with variable stroke
US6810665B2 (en) * 2002-12-13 2004-11-02 Industrial Technology Research Institute Stirling engine with variable stroke
US20100202900A1 (en) * 2007-08-07 2010-08-12 Robert Bosch Gmbh Hydrostatic machine having a control device having a return element for controlling a regulating valve
US9297369B2 (en) * 2007-08-07 2016-03-29 Robert Bosch Gmbh Hydrostatic machine having a control device having a return element for controlling a regulating valve

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Publication number Publication date
JPS4940242B1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1974-11-01

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