US3742821A - Arrangement for controlling regulatable pumps - Google Patents

Arrangement for controlling regulatable pumps Download PDF

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Publication number
US3742821A
US3742821A US00184095A US3742821DA US3742821A US 3742821 A US3742821 A US 3742821A US 00184095 A US00184095 A US 00184095A US 3742821D A US3742821D A US 3742821DA US 3742821 A US3742821 A US 3742821A
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United States
Prior art keywords
piston
pressure
fluid
arrangement
center position
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Expired - Lifetime
Application number
US00184095A
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English (en)
Inventor
G Martin
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.)
Claas Maschinenfabrik GmbH
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Claas Maschinenfabrik GmbH
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Publication date
Application filed by Claas Maschinenfabrik GmbH filed Critical Claas Maschinenfabrik GmbH
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Publication of US3742821A publication Critical patent/US3742821A/en
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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

Definitions

  • a control piston is slidable in the housing to opposite sides of a center position and is provided with a pair of axially saced grooves in its outer periphery which, when the piston is in center position, are located at opposite axial sides of the groove in the inner surface of the cylinder housing.
  • a side member is guided in a stepped bore of the piston for axial sliding movement relative thereto and defines with the piston two pressure chambers each of which communicates with one of the outer grooves of the piston, and each of the chambers is provided with a relatively small port connecting it with a pressure fluid venting conduit.
  • the present invention relates generally to control arrangements, and more particularly to control arrangements for controlling regulatable pumps. Still more particularly the invention relates to an arrangement for controlling a regulatable hydraulic pump, particularly but not exclusively an axial piston pump.
  • German Pat. No. 1,601 ,701 discloses an arrangement of this general character which affords precise centering of the control piston in automatic manner.
  • the control piston operates as a differential piston with the piston rod being configurated as an additional control member.
  • the actual slide member in this construction is connected with an actuating rod with a predeter mined axial play, which axial rod is provided with control surfaces and control bores in order to obtain fixing of the center position of the control piston. It has been found, however, that this prior-art construction is economically not well feasible because it is rather complicated in its construction and therefore expensive in its production.
  • control piston is configurated as a differential piston, and in order'to control the piston it is necessary to use oil from the main pressure oil circuit, requiring the provision of additional devices which act as force amplifiers when the control piston is to be moved out of its exact center position in which the pump is in zero setting position and no oil is passed through the main circuit.
  • a concomitant object of the invention is to provide such an arrangement which is very simple in its construction and therefore to produce, and which fulfills the requirements made of it in wholly satisfactory manner.
  • a combination is provided of a cylinder housing having an inner circumferential surface, and a control piston slidable in the housing to opposite sides of a center position.
  • the invention further provides an inner groove in the surface of the cylinder housing, being positioned to coincide with the center position and in communication with the source of pressure fluid.
  • a pair of axially spaced outer grooves encircle the piston and are located at opposite axial sides of the inner groove when the piston is in its center position.
  • a slide member is guided in the piston for axial sliding movement relative thereto and defines therewith two pressure chambers each communicating with one of the outer grooves.
  • a pair of relatively small ports are provided, each connecting one of the chambers with a pressure fluid venting conduit.
  • the arrangement is connected in the feed circuit of a pump which supplies or replenishes pressure fluid lost as a result of leakage.
  • FIG. 1 is a somewhat diagrammatic longitudinal section through one embodiment of the invention
  • FIG. 2 is a section similar to FIG. 1, taken in a plane at right angles to that of FIG. 1 and omitting details exteriorly of the device and which are the same as in FIG. 1;
  • FIG. 3 is a view similar to FIG. 2 but illustrating a further embodiment of the invention.
  • FIGS. l and 2 DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing now the drawing in detail, and firstly the embodiment which is illustrated in FIGS. l and 2, it will be seen that reference numeral ll has been utilized to designate the regulatable pump which is to be controlled. Such pumps are already known per se and require no detailed discussion.
  • the regulating device for the pump l is identified with reference numeral 2 and is moved or maintained against movement by the control piston 7, via a linkage 3, a connecting member 4, a pivot 5 and a member 6.
  • control piston 7 is slidably accommodated in a cylinder housing 8 and is provided with an axial stepped bore which in turn accommodates a slide member 9, a dished spring lit) and dish springs 11.
  • a replenishing pump 12 supplies pressure fluid, for instance oil, via the conduits l3 and 14 to the one-way valves 15, via which leakage oil or oil which is used in the main fluid circuit, is replenished.
  • the pump 12 supplies oil via the conduit llfi, the bore 19, the longitudinal groove 20 and the bore 21 into the control chamber 22 which is defined between or by the members 7 and 9. Excess oil supplied by the pump 12 flows via conduits l3 and 14, and via the pressure-limiting valve 23 into the oil reservoir 36.
  • FIG. 1 also shows that the slide member 9 is provided with cylindrical control surfaces 24 and 25 which close the bores 26 and 27 in the center position, and that the member 9 is further provided with cylindrical recesses 28 and 29 which are connected via bores 30 and 31 of the center bore 32 in the member 9, free space 33 in the piston 7, bore 34 and conduit 35 with the reservoir 36.
  • the inner circumferential surface of the cylinder 8 is provided with an inner groove 39 and which is connected with the connection 19 of the pump 12 so that it is continuously under pressure.
  • a control surface 40 provided on the piston 7 closes the groove 39 and is delimited at opposite lateral sides by the outer grooves 41 and 42 provided in the piston-7.
  • the width of the groove 39 and of the grooves 41 and 42 is determinative of the length of the path required for the center position return.
  • the pretension springs 11 press the member 9 with the spring to its center orzero setting position, and oil in the chamber 45 escapes through the groove 49 into the space 28 and from there into the reservoir 36.
  • the groove 49 could, of course, be omitted if the bead of the member 9 were to be accommodated in the bore of the piston 7 with greater play than illustrated.
  • FIG. 3 is largely the same as that in FIGS. 1 and 2, and any extraneous componentssuch as the pump 1, the device 2, etc.- which are shown in FIG. 1 have not been included in FIG. 3 because they should be understood as being the same as in FIG. 1.
  • the embodiment in FIG. 3 in fact differs from that in FIGS. 1 and 2 only in that the pressure chambers 45a and 46a in this embodiment are not delimited by the actual bore accommodating the member 9, but instead by the walls oflarger bores which are provided at opposite ends of the bore for the member 9 and which accommodate pistons closing the chambers 45a and 46a.
  • the bores from the grooves 410 and 42a to the chambers 45a and 46a are arranged analogously to those illustrated in FIG. 2, and the operation of the embodiment in FIG. 3 is the same as that in FIGS. 1 and 2.
  • a cylinder housing having an inner circumferential surface; a control piston slidable in said housing to opposite sides of a center position, said piston defining at its opposite axial ends a first and a second fluid chamber; an inner groove in said surface, positioned to coincide with said center position and in communication with a source of pressure fluid; a pair of axially spaced outer grooves encircling said piston and located at opposite axial sides of said inner groove when said piston is in said center position; a slide member guided in said piston for axial sliding movement relative thereto and defining therewith two pressure chambers each communicating with one of said outer grooves; a pair of relatively small ports each connecting one of said chambers with a pressure-fluid venting conduit; and passage means communicating with the respective fluid chambers and controlled by said slide member so that, when said slide member moves towards said first
  • said piston having a stepped axial passage, and said slide member being at least in part slidably received in said passage.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Reciprocating Pumps (AREA)
  • Hydraulic Motors (AREA)
  • Actuator (AREA)
  • Control Of Fluid Gearings (AREA)
  • Details Of Reciprocating Pumps (AREA)
US00184095A 1970-09-30 1971-09-27 Arrangement for controlling regulatable pumps Expired - Lifetime US3742821A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2047977A DE2047977C3 (de) 1970-09-30 1970-09-30 Anordnung zum Steuern von regelbaren Hydraulikpumpen

Publications (1)

Publication Number Publication Date
US3742821A true US3742821A (en) 1973-07-03

Family

ID=5783749

Family Applications (1)

Application Number Title Priority Date Filing Date
US00184095A Expired - Lifetime US3742821A (en) 1970-09-30 1971-09-27 Arrangement for controlling regulatable pumps

Country Status (4)

Country Link
US (1) US3742821A (enrdf_load_stackoverflow)
DE (1) DE2047977C3 (enrdf_load_stackoverflow)
FR (1) FR2108309A5 (enrdf_load_stackoverflow)
GB (1) GB1314127A (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3908518A (en) * 1971-09-20 1975-09-30 Oilgear Co Fluid device having constant horsepower displacement control means
US6119456A (en) * 1998-01-21 2000-09-19 Sauer Inc. Displacement control with load feedback and stroke control for a hydraulic unit
US20060242956A1 (en) * 2005-04-14 2006-11-02 Ryota Ohashi Hydraulic pump unit and working vehicle

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2620524C2 (de) * 1976-05-10 1986-08-28 Linde Ag, 6200 Wiesbaden Steuereinrichtung für die Schwenklage eines Schwenkkörpers
US4050247A (en) * 1976-10-07 1977-09-27 Eaton Corporation Control valve for variable displacement pump or motor
DE2825790C2 (de) * 1978-06-13 1982-08-05 Danfoss A/S, 6430 Nordborg Stellmotor mit Nachlaufsteuerung
DE3112561C2 (de) 1981-03-30 1985-09-26 Danfoss A/S, Nordborg Steuervorrichtung für eine Flüssigkeitspumpe mit verstellbarem Fördervolumen

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3017750A (en) * 1959-07-13 1962-01-23 Dowty Hydraulic Units Ltd Hydraulic apparatus
US3677138A (en) * 1970-11-19 1972-07-18 Bendix Corp Mechanism for hydraulic brake booster

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3017750A (en) * 1959-07-13 1962-01-23 Dowty Hydraulic Units Ltd Hydraulic apparatus
US3677138A (en) * 1970-11-19 1972-07-18 Bendix Corp Mechanism for hydraulic brake booster

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3908518A (en) * 1971-09-20 1975-09-30 Oilgear Co Fluid device having constant horsepower displacement control means
US6119456A (en) * 1998-01-21 2000-09-19 Sauer Inc. Displacement control with load feedback and stroke control for a hydraulic unit
US20060242956A1 (en) * 2005-04-14 2006-11-02 Ryota Ohashi Hydraulic pump unit and working vehicle
US7500361B2 (en) * 2005-04-14 2009-03-10 Kanzaki Kokyukoki Mfg. Co., Ltd. Hydraulic pump unit and working vehicle

Also Published As

Publication number Publication date
FR2108309A5 (enrdf_load_stackoverflow) 1972-05-19
DE2047977B2 (de) 1973-09-06
GB1314127A (en) 1973-04-18
DE2047977C3 (de) 1974-04-04
DE2047977A1 (de) 1972-04-06

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