EP0455059A1 - Zahnradpumpe - Google Patents

Zahnradpumpe Download PDF

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Publication number
EP0455059A1
EP0455059A1 EP91106237A EP91106237A EP0455059A1 EP 0455059 A1 EP0455059 A1 EP 0455059A1 EP 91106237 A EP91106237 A EP 91106237A EP 91106237 A EP91106237 A EP 91106237A EP 0455059 A1 EP0455059 A1 EP 0455059A1
Authority
EP
European Patent Office
Prior art keywords
recess
gears
axis
notches
area
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.)
Withdrawn
Application number
EP91106237A
Other languages
English (en)
French (fr)
Inventor
Luciano Bucarelli
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.)
FiatGeotech Technologie per la Terra SpA
FiatGeotech SpA
Original Assignee
FiatGeotech Technologie per la Terra SpA
FiatGeotech SpA
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 FiatGeotech Technologie per la Terra SpA, FiatGeotech SpA filed Critical FiatGeotech Technologie per la Terra SpA
Publication of EP0455059A1 publication Critical patent/EP0455059A1/de
Withdrawn legal-status Critical Current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
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2/00—Rotary-piston machines or pumps
    • F04C2/08—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C2/082—Details specially related to intermeshing engagement type machines or pumps
    • F04C2/088—Elements in the toothed wheels or the carter for relieving the pressure of fluid imprisoned in the zones of engagement

Definitions

  • the present invention relates to a gear pump of an improved type with reduced noise.
  • gear pumps have two gears, one driven and the other a drive gear, which intermesh and have respective hubs supported by two figure-of-eight-shaped bushes.
  • An induction port and a delivery port are defined on opposite sides of the meshing zone.
  • Some companies have formed notches in the grazing faces, that is, in the surfaces of the figure-of-eight-shaped bushes facing the lateral faces of the gears, in correspondence with the meshing zone, both on the induction side and on the delivery side.
  • the sole purpose of these notches is to allow the liquid which is present on the grazing faces to escape and hence does not solve the noise problem.
  • Other companies have formed a duct between the notches in order to solve this problem but this puts the induction port in communication with the delivery port. This solves the noise problem but, as will be clear, causes a corresponding reduction in the performance of the pump.
  • the object of the present invention is to provide a gear pump which does not have the disadvantage mentioned above, that is, which is less noisy without thereby impairing the performance of the pump itself.
  • the present invention provides a gear pump of the type comprising: a pump body ; two meshing gears housed in the pump body, of which one is driven and the other is a drive gear; two ports formed in the pump body on opposite sides of the gear meshing zone and of which one is a liquid intake port and the other is a delivery port; two bushes fitted at the sides of the gears, each supporting hub portions of the latter and defining respective faces in grazing relationship with the gears; characterised in that the grazing face of each of the bushes is formed with a first recess of predetermined depth relative to a central axis defined by the line joining the axes of the gears, formed on the intake side and in hydraulic communication with the intake port, and a second recess formed on the delivery side in hydraulic communication with the delivery port and having a depth towards the central axis such as to maintain hydraulic communication with an area which is defined between the teeth of the gears in the said meshing zone and in which a quantity of liquid remains enclosed until the point at which the said
  • a gear pump generally indicated 1 comprises a pump body 2, the two sides of which are closed by respective cover plates 3 and 4 and in which two meshing gears 5 and 6 are installed.
  • the gear 5 is a driven gear and has a hub 7 whose length is substantially equal to that of the pump body 2.
  • the gear 6 is a drive gear and has a hub 8 which at one end extends beyond the plate 3 where it is connected mechanically to an output shaft of an engine, not illustrated.
  • the plate 3 has a through-hole 11 traversed by the hub 8.
  • the hubs 7 and 8 are supported by two support bushes 13 located on opposite sides of the gears 5 and 6 and having respective faces 14 in grazing relationship with the tips of the teeth of these latter.
  • the pump 1 also has two hydraulic seal assemblies 19 between the plates 3 and 4 and the pump body 2 and the outer faces of the bushes 13 respectively.
  • the pump body 2 has an internal shape which reproduces the peripheral shape of the pair of gears 5 and 6, that is a figure-of-eight shape.
  • the bushes 13 have a peripheral figure-of-eight shape and, naturally, each bush 13 has two parallel through-holes 15 for housing portions of the hubs 7 and 8 with the interposition of respective bushes 16.
  • the pump body 2 is formed with an intake port 17 on one side of the meshing zone of the gears 5 and 6 and with a delivery port 18 on the opposite side.
  • the gears 5 and 6 have a predetermined number of teeth 21 such as to cause more than one tooth 21 of each gear 5 and 6 to be in mesh at any one time.
  • the shape of the teeth 21 is known and is such as to cause hydraulic sealing between the surfaces in contact during meshing. Due to the shape of the teeth 21 and the number of these which are in mesh, there is no direct hydraulic communication between the ports 17 and 18 in the meshing zone.
  • the grazing faces of both of the bushes 13 are formed with recesses 22 and 23 in correspondence with the meshing zone.
  • the recess 22 is on the induction side and is thus in hydraulic communication with the induction port 17.
  • This recess 22 is defined by two notches 24 and 25 which intercommunicate at their bases and which extend in parallel towards a (central) axis "C" defined by the line joining the axes of the holes 15.
  • the notches 24 and 25 are essentially of triangular-wedge shape with respective ends 26 rounded and lying on a straight line "A" (intake side) parallel to the axis "C” and spaced therefrom by a distance "a”.
  • the recess 23 is on the delivery side and is thus in hydraulic communication with the delivery port 18.
  • the recess 23 is also constituted by two notches 27 and 28 which intercommunicate at their bases and which extend in parallel towards the axis "C”.
  • the notches 27 and 28 are also of essentially triangular-wedge shape with respective ends 31 which are rounded and lie on a straight line "M" (delivery side) parallel to the axis "C” and spaced therefrom by a distance "b”.
  • the recesses 22 and 23, while having a similar shape, are not symmetrical about the axis C but, on the contrary, the distance "a" is greater than the distance "b". More particularly, the common base of the notches 27 and 28 is deeper in the direction of the axis "C" than that defined by the notches 24 and 25, while the depths of the various notches 24 and 25, and 27 and 28, starting from their common bases, are substantially equal.
  • the formation of the recesses 22 and 23 serves two purposes the first of which is to allow the escape of liquid present on the grazing faces 14 as occurs in other, known pumps.
  • the second purpose, which is determined by the novel conformation of the recesses 22 and 23, is to avoid a phase in which the liquid is compressed in the meshing zone which, it will be remembered, causes noise and wear on the various components of the pump.
  • Figures 3, 4 and 5 schematically illustrate the situations which are created successively in the meshing zone. More particularly, three areas 32, 33 and 34 can be distinguished in Figure 3, of which the area 32 is defined by the recess 22 and is represented by a plurality of "+" signs.
  • the area 33 is defined between two contiguous teeth 21a and 21b of the gear 5 (the tooth 21b of which is immediately in front of the other with reference to the sense of rotation of the gear 5) and two contiguous teeth 21c and 21d of the gear 6 (the tooth 21d of which is immediately in front of the other with reference to the sense of rotation of the gear 6).
  • the area 33 is represented by a plurality of ".” signs and "-" signs.
  • the area 34 is defined by the recess 23 and is represented by a plurality of "-" signs.
  • the area 33 is hydraulically sealed from the area 32 due to the contact between the teeth 21b and 21d while it communicates with the area 34 through the notch 27, the end portion of which underlies a part of the area 33. Naturally the areas 32 and 34 are not in hydraulic communication with each other.
  • the illustration of the area 33 in Figure 3 relates to the instant at which the teeth 21a and 21c come into contact.
  • the area 33 has a specific size which, in subsequent moments, tends to diminish until it reaches a minimum size which occurs when the tooth 21a almost fully occupies the space between the teeth 21c and 21d.
  • the depth of the recess 23 and, in particular, of the notch 27 is such that, when the area 33 has its minimum size, there is no hydraulic communication between the area 34 and the area 33, which is completely sealed.
  • Figure 4 illustrates this final situation and, for this reason, the area 33 is shown only by a plurality of ".” signs. In passage from the situation illustrated in Figure 3 to that illustrated in Figure 4, there is thus a reduction in the size of the area 33 which does not, however, result in any compression of the liquid since the area 33 is still in communication with the area 34.
  • the size of the area 33 increases progressively until the situation illustrated in Figure 5 is reached in which this area 33 has its maximum size.
  • the situation illustrated in Figure 5 relates to the first instant of hydraulic communication between the area 32 and the area 33 which is still sealed from the area 34.
  • the phase in which the liquid is compressed during the reduction in the size of the area enclosed between the teeth of the gears in the meshing zone thereof is avoided. This is achieved by putting this area into hydraulic communication with the delivery port up to the instant at which the minimum size is reached.
  • the hydraulic communication just described is achieved by the appropriate shaping of the recesses 22 and 23 and, in particular, by the formation of the recess 23 with a predetermined depth extending towards the central axis "C" which is different from, and more specifically greater than, that of the recess 22.
  • each bush 13 may be formed in one piece or in two pieces which are fitted together in the zone in which the recesses 22 and 23 are formed; for each of these latter, a first notch 24 and 27 is formed in a first piece and the other notch 25 and 28 is formed in the second piece.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Lubrication Of Internal Combustion Engines (AREA)
  • Rotary Pumps (AREA)
EP91106237A 1990-04-26 1991-04-18 Zahnradpumpe Withdrawn EP0455059A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT3462A IT1238912B (it) 1990-04-26 1990-04-26 Pompa ad ingranaggi.
IT346290 1990-04-26

Publications (1)

Publication Number Publication Date
EP0455059A1 true EP0455059A1 (de) 1991-11-06

Family

ID=11107829

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91106237A Withdrawn EP0455059A1 (de) 1990-04-26 1991-04-18 Zahnradpumpe

Country Status (2)

Country Link
EP (1) EP0455059A1 (de)
IT (1) IT1238912B (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0519276A1 (de) * 1991-06-19 1992-12-23 Eaton Corporation Fluidumdruck-Übertragungsmittel für Auflader
EP0677660A1 (de) * 1994-04-07 1995-10-18 Maag Pump Systems AG Zahnradpumpe und deren Verwendung
EP1081381A3 (de) * 1999-09-06 2002-09-11 Koyo Seiko Co., Ltd. Zahnradpumpe
EP1832750A1 (de) 2006-03-10 2007-09-12 Schwäbische Hüttenwerke Automotive GmbH & Co. KG Außenzahnradpumpe mit Entlastungstasche
DE102016206023A1 (de) 2016-04-12 2017-10-12 Volkswagen Aktiengesellschaft Fluidpumpe, insbesondere für ein Kraftfahrzeug
US11028847B2 (en) * 2019-03-02 2021-06-08 Brose Fahrzeugteile GmbH & Co. Kommanditgesellschaft, Würzburg Gear pump for venting trapped volume

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB781697A (en) * 1955-04-14 1957-08-21 Borg Warner Improvements in or relating to gear type pumps
GB857046A (en) * 1956-10-05 1960-12-29 Parker Hannifin Corp Improved gear pump
US3690793A (en) * 1971-01-27 1972-09-12 Sundstrand Corp Gear pump with lubricating means
FR2352947A1 (fr) * 1976-05-25 1977-12-23 Bosch Gmbh Robert Machine a engrenage (pompe ou moteur)
GB2012876A (en) * 1978-01-18 1979-08-01 Lucas Industries Ltd Rotary Hydraulic Pumps

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB781697A (en) * 1955-04-14 1957-08-21 Borg Warner Improvements in or relating to gear type pumps
GB857046A (en) * 1956-10-05 1960-12-29 Parker Hannifin Corp Improved gear pump
US3690793A (en) * 1971-01-27 1972-09-12 Sundstrand Corp Gear pump with lubricating means
FR2352947A1 (fr) * 1976-05-25 1977-12-23 Bosch Gmbh Robert Machine a engrenage (pompe ou moteur)
GB2012876A (en) * 1978-01-18 1979-08-01 Lucas Industries Ltd Rotary Hydraulic Pumps

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0519276A1 (de) * 1991-06-19 1992-12-23 Eaton Corporation Fluidumdruck-Übertragungsmittel für Auflader
EP0677660A1 (de) * 1994-04-07 1995-10-18 Maag Pump Systems AG Zahnradpumpe und deren Verwendung
US5547356A (en) * 1994-04-07 1996-08-20 Maag Pump Systems Ag Gear pump and method of using same
EP1081381A3 (de) * 1999-09-06 2002-09-11 Koyo Seiko Co., Ltd. Zahnradpumpe
EP1832750A1 (de) 2006-03-10 2007-09-12 Schwäbische Hüttenwerke Automotive GmbH & Co. KG Außenzahnradpumpe mit Entlastungstasche
DE102016206023A1 (de) 2016-04-12 2017-10-12 Volkswagen Aktiengesellschaft Fluidpumpe, insbesondere für ein Kraftfahrzeug
US11028847B2 (en) * 2019-03-02 2021-06-08 Brose Fahrzeugteile GmbH & Co. Kommanditgesellschaft, Würzburg Gear pump for venting trapped volume

Also Published As

Publication number Publication date
IT9003462A0 (it) 1990-04-26
IT9003462A1 (it) 1991-10-27
IT1238912B (it) 1993-09-07

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