EP0664395A1 - Pompe à engrenage internes - Google Patents

Pompe à engrenage internes Download PDF

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Publication number
EP0664395A1
EP0664395A1 EP95300338A EP95300338A EP0664395A1 EP 0664395 A1 EP0664395 A1 EP 0664395A1 EP 95300338 A EP95300338 A EP 95300338A EP 95300338 A EP95300338 A EP 95300338A EP 0664395 A1 EP0664395 A1 EP 0664395A1
Authority
EP
European Patent Office
Prior art keywords
sealing
outlet port
pump
land
groove
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Withdrawn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
EP95300338A
Other languages
German (de)
English (en)
Inventor
Simon Baseley
Andrew Turner
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.)
Hobourn Automotive Ltd
Original Assignee
Hobourn Automotive 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 Hobourn Automotive Ltd filed Critical Hobourn Automotive Ltd
Publication of EP0664395A1 publication Critical patent/EP0664395A1/fr
Withdrawn legal-status Critical Current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
    • F04C15/00—Component parts, details or accessories of machines, pumps or pumping installations, not provided for in groups F04C2/00 - F04C14/00
    • F04C15/06—Arrangements for admission or discharge of the working fluid, e.g. constructional features of the inlet or outlet
    • 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
    • F04C15/00—Component parts, details or accessories of machines, pumps or pumping installations, not provided for in groups F04C2/00 - F04C14/00
    • F04C15/0042—Systems for the equilibration of forces acting on the machines or pump
    • F04C15/0049—Equalization of pressure pulses

Definitions

  • This invention relates to pumps and is more particularly concerned with gerotor pumps, sometimes known as N(N-1) type pumps.
  • Gerotor pumps are in common use as engine lubricating pumps, the inner rotor being driven by a shaft geared to the crankshaft or being driven directly from the crankshaft. They are positive displacement pumps in which discrete volumes of oil contained in the pumping chambers pass between suction and pressure ports in the end plates. In consequence the output flow fluctuates due to geometric effects and due to the compression of the low pressure oil as it becomes exposed to the high pressure in the output port. This compression effect becomes more marked if the oil in the sump becomes aerated significantly due to the operation of the engine.
  • the effect of output flow fluctuation is to cause a pressure variation at a frequency which is a multiple of the number of teeth on the driven rotor and the rotational speed, and under certain circumstances this cyclic pressure variation can cause excitation of the engine structure or associated systems sufficiently to emit undesirable noise.
  • the purpose of the present invention is to reduce the severity of volume fluctuation, particularly where aerated oil is present.
  • One benefit of this is to reduce undesirable noise in sensitive installations.
  • a gerotor pump comprising a housing, an inner rotor having a lobed outer periphery and mounted for rotation in the housing, an outer rotor encircling the inner rotor and having a lobed inner periphery, the outer rotor being mounted in the housing for rotation about an axis which is eccentric relative to the axis of rotation of the inner rotor, the lobes of the two rotors interengaging to define a series of pumping chambers, and means defining radial surfaces in sealing engagement with the two rotors at opposite axial sides thereof, at least one of which surfaces has therein a circumferentially extending inlet port, a circumferentially extending outlet port and sealing lands forming seals between the inlet and outlet ports, the sealing land disposed at or adjacent the location at which the pumping chambers have their maximum volume having in its face a groove extending circumferentially from the outlet port towards but terminating short of the inlet port.
  • the sealing land having said groove therein has a circumferential length greater than the circumferential distance between successive points of sealing contact between the two rotors at the location of the said sealing land.
  • the circumferential length of the said sealing land may, for example, be 11 ⁇ 2 to 2 times the circumferential distance between said successive points of contact.
  • the pump comprises an inner rotor 10 mounted on a drive shaft 11 carried in a bearing in the pump housing 12, and an outer rotor 13 rotatably mounted eccentrically with respect to the inner rotor in a cylindrical recess 14 in the housing.
  • the recess is closed off by an end plate (not shown) which forms a seal with the axially outer end faces of the two rotors.
  • the inner rotor has lobes 15 on its outer periphery and the outer rotor has lobes 16 on its inner periphery, the number of lobes on the outer rotor being greater by one than the number of lobes on the inner rotor, so that a series of pumping chambers 17 are defined between the two sets of lobes and have minimum and maximum volumes at opposite sides of the two axes of rotation 18, 19 on extensions 20 of a line joining the two axes.
  • the inner end wall of the recess in the housing forms a seal with the adjacent ends of the two rotors and is formed with a circumferentially extending inlet port 21 and a circumferentially extending outlet port 22.
  • the ports 21, 22 are shown in full lines in Figure 1 for convenience, but are behind the rotors 10, 13. Where the lobes of the two rotors are in deepest interengagement, the end wall of the recess has a first sealing land 23 separating the two ports, and where the lobes are in least deep interengagement a second sealing land 24 separates the two ports.
  • the rotor 10 is driven in the direction of the arrow, so that as each pumping chamber 17 passes the first sealing land 23 its volume is a minimum but increases with continuing rotation, drawing working fluid into the chamber from the inlet port 21.
  • each pumping chamber reaches the second sealing land 24 its volume is a maximum and is sealed by that land, the circumferential length of the land being substantially equal to the circumferential distance l between the sealing points between the four lobes defining the chamber 17 at that point.
  • the sealing land 24 is displaced a few degrees round in the direction of rotation of the rotors to provide more time for the pumping chambers to fill, but the principle of operation is unchanged.
  • the porting arrangement in a pump according to the invention is shown.
  • the length of the second sealing land 24 is increased, reducing the circumferential length of the outlet port 22 but leaving the inlet port 21 unchanged.
  • the length of the land 24 in this construction is typically up to 2 times the circumferential length l of the pumping chambers as they pass that land.
  • a groove 26 extends generally circumferentially along the land from the outlet port 22 towards but terminates well short of the inlet port 21.
  • the groove has its greatest cross-section at its end opening to the outlet port and the cross-section reduces progressively to zero at a position spaced from the opposite end of the land by a distance l equal to the distance between the seals of the adjacent pumping chambers.
  • the compression may be insufficient to raise the pressure in the chamber to the value existing in the outlet port.
  • the presence of the groove 26 operates to permit more gradual equalization of the pressures in the outlet port and the pumping chambers.
  • oil can flow from the pumping chamber along the groove to the outlet port reducing the pressure in the pumping chamber gradually.
  • oil can flow along the groove from the outlet port to the pumping chamber to raise the pressure in the pumping chamber. The progressive nature of this transfer of oil prevents sudden volume changes and hence sudden pressure changes as the pumping chambers come into communication with the outlet port, and thus reduces noise and vibrations which may occur in some installations.
  • the maximum length of the groove is such as to prevent significant direct leakage past land 24 from the outlet to the inlet port, and for this reason the groove will commence not normally nearer to the inlet port than a distance equal to l.
EP95300338A 1994-01-19 1995-01-19 Pompe à engrenage internes Withdrawn EP0664395A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9400989 1994-01-19
GB9400989A GB9400989D0 (en) 1994-01-19 1994-01-19 Improvements in or relating to pumps

Publications (1)

Publication Number Publication Date
EP0664395A1 true EP0664395A1 (fr) 1995-07-26

Family

ID=10749030

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95300338A Withdrawn EP0664395A1 (fr) 1994-01-19 1995-01-19 Pompe à engrenage internes

Country Status (2)

Country Link
EP (1) EP0664395A1 (fr)
GB (1) GB9400989D0 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19626153A1 (de) * 1995-06-30 1997-01-09 Jatco Corp Zahnradpumpe
GB2324573A (en) * 1996-12-02 1998-10-28 Ford Motor Co Gerotor pump
DE102013226852A1 (de) 2013-12-20 2015-06-25 Volkswagen Aktiengesellschaft Zahnradpumpe

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB894669A (en) * 1959-12-22 1962-04-26 Hobourn Eaton Mfg Co Ltd Rotary pump
CH493740A (de) * 1968-07-12 1970-07-15 Danfoss As Zahnradpumpe
US4767296A (en) * 1984-10-31 1988-08-30 Aisin Seiki Kabushiki Kaisha Trochoidal toothed oil pump with thin discharge channel communicating with discharge chamber

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB894669A (en) * 1959-12-22 1962-04-26 Hobourn Eaton Mfg Co Ltd Rotary pump
CH493740A (de) * 1968-07-12 1970-07-15 Danfoss As Zahnradpumpe
US4767296A (en) * 1984-10-31 1988-08-30 Aisin Seiki Kabushiki Kaisha Trochoidal toothed oil pump with thin discharge channel communicating with discharge chamber

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19626153A1 (de) * 1995-06-30 1997-01-09 Jatco Corp Zahnradpumpe
US5711660A (en) * 1995-06-30 1998-01-27 Jatco Corporation Internal gear type rotary pump having a relief groove
DE19626153C2 (de) * 1995-06-30 1999-02-25 Jatco Corp Innenzahnradpumpe
GB2324573A (en) * 1996-12-02 1998-10-28 Ford Motor Co Gerotor pump
GB2324573B (en) * 1996-12-02 2001-02-14 Ford Motor Co Gerotor pump
DE102013226852A1 (de) 2013-12-20 2015-06-25 Volkswagen Aktiengesellschaft Zahnradpumpe

Also Published As

Publication number Publication date
GB9400989D0 (en) 1994-03-16

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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AK Designated contracting states

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Designated state(s): DE FR GB IT

17P Request for examination filed

Effective date: 19951218

17Q First examination report despatched

Effective date: 19961210

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18D Application deemed to be withdrawn

Effective date: 19970621