EP2582981A2 - Machine à fluide à engrenage à régulation de débit - Google Patents

Machine à fluide à engrenage à régulation de débit

Info

Publication number
EP2582981A2
EP2582981A2 EP11735549.5A EP11735549A EP2582981A2 EP 2582981 A2 EP2582981 A2 EP 2582981A2 EP 11735549 A EP11735549 A EP 11735549A EP 2582981 A2 EP2582981 A2 EP 2582981A2
Authority
EP
European Patent Office
Prior art keywords
regulating member
machine
fluidic
pressure
fluid
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Withdrawn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
EP11735549.5A
Other languages
German (de)
English (en)
Inventor
Armando Codeca'
Matteo Cortesi
Leonardo Cadeddu
Alessandro Fauda
Matteo Calderoni
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.)
VHIT SpA
Original Assignee
VHIT 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 VHIT SpA filed Critical VHIT SpA
Publication of EP2582981A2 publication Critical patent/EP2582981A2/fr
Withdrawn legal-status Critical Current

Links

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
    • F04C2/10—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of internal-axis type with the outer member having more teeth or tooth-equivalents, e.g. rollers, than the inner member
    • F04C2/102—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of internal-axis type with the outer member having more teeth or tooth-equivalents, e.g. rollers, than the inner member the two members rotating simultaneously around their respective axes
    • 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
    • F04C11/00—Combinations of two or more machines or pumps, each being of rotary-piston or oscillating-piston type; Pumping installations
    • F04C11/001—Combinations of two or more machines or pumps, each being of rotary-piston or oscillating-piston type; Pumping installations of similar working principle
    • 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
    • F04C14/00—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations
    • F04C14/24—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves
    • F04C14/26—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves using bypass channels
    • F04C14/265—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves using bypass channels being obtained by displacing a lateral sealing face

Definitions

  • the present invention relates to fluidic machines, and more particularly it concerns an internal gear fluidic machine, in particular a positive displacement pump, with flow rate regulation.
  • the present invention is applied in a pump for the lubrication oil of an internal combustion engine, typically for a motor vehicle engine.
  • pumps with internal epicyclic gears are often used. These pumps generally comprise: a stationary body; an external gear rotating in said body about a first axis and having an internal toothing; an internal gear rotating inside the external gear about a second axis, different from the first one, and having an external toothing, with a number of teeth different from that of the external gear (generally, with one tooth less), meshing with the internal toothing of the external gear with only partial hydraulic seal; and a transmission member, generally driven by the vehicle engine, in order to impart the rotation to one of the two gears, which in turn drives the other because of the meshing of the respective toothings.
  • the teeth define a succession of variable volume chambers between them, and oil is conveyed from an intake port to a discharge port through said chambers.
  • the oil flow rate at the outlet depends on the rotation speed of the engine, and therefore the pumps are designed so as to provide a sufficient flow rate at low speed, in order to ensure lubrication also in such conditions. If the pump has a fixed geometry, at high rotation speed the flow rate (and hence the pressure in the engine lubrication circuit) is higher than that required, resulting in an unnecessary energy consumption and, eventually, in an increase in fuel consumption and hence in a higher environment pollution.
  • EP 1 091 126 A discloses a pump in which a flow rate regulation is obtained by varying the intake and delivery phases depending on the rotation speed of the engine. This is obtained through the rotation of a plate that separates the intake and delivery chambers and that is made to rotate when a pressure threshold is exceeded. Such rotation causes a reduction in the duration of the delivery phases, with a consequent choking effect on the fluid, and gives rise to oil recirculation.
  • a drawback of this prior art pump is the possibility of occurrence of strong cavitation phenomena especially at high rotation speed.
  • Another drawback, also depending on the presence of rotating members, is the relative complexity.
  • the plate drive is an indirect drive and requires the provision of a pressure-responsive member that, when displacing, in turn drives the plate through a rack and pinion mechanism. This makes the pump construction still more complex and the reaction slower.
  • the machine includes a regulating member that is mounted so as to be axially slidable, without rotating, in a seat formed in the body of the machine itself and that has a first surface for pressure application, which is permanently exposed to the pressure of the fluid circulating in a fluidic circuit in which the machine is connected and which is arranged, when a pressure threshold is exceeded, to cause a sliding of the regulating member in order to move it away from a rest position, where no flow rate regulation occurs, and to create a fluid recirculation path between two chambers at different pressures in the machine.
  • the regulating member further has at least one second surface for pressure application, which is exposed to the fluid pressure upon an external command, in order to make the regulating member slide and to create a fluid recirculation path independently of whether the threshold is exceeded.
  • the invention also concerns a method of regulating the flow rate of an internal gear fluidic machine, comprising:
  • a moving member for flow rate regulation within the machine body, a moving member for flow rate regulation, the movement of which is controlled by the fluid pressure conditions in a fluidic circuit in which the machine is connected, and which can be made to axially slide, without rotating;
  • the method also comprises exposing also at least one second surface for pressure application to said fluid pressure conditions, upon an external command, to make the regulating member slide and to create the fluid recirculation path independently of whether said threshold is exceeded.
  • the invention concerns a pumping system, preferably for use in motor vehicles, comprising a plurality of mutually coupled pumping subsystems, wherein one of the subsystems is a pump for the lubrication oil of an engine made in accordance with the invention.
  • - Fig. 1 is a partial view in axial section of a pump according to the invention, taken along plane I-I of Fig. 2 and showing the pump when no flow rate regulation takes place;
  • FIG. 2 is a cross-sectional view of the pump shown in Fig. 1 , taken along plane II-II of Fig. 1;
  • FIG. 3 is an enlarged view in axial section of the moving cover and the pump body parts cooperating therewith;
  • Fig. 4 is a view similar to Fig. 1, showing the pump in conditions of maximum flow rate reduction;
  • Fig. 5 is a diagram of an engine lubrication circuit in which the pump according to the invention is connected;
  • Fig. 6 is a view similar to Fig. 1, showing a variant embodiment of the invention
  • - Fig. 7 is a view in axial section of a combined pump using the present invention.
  • the pump according to the invention is a positive displacement pump with internal epicyclic gears.
  • the pump comprises, in conventional manner, an external gear 2 having an internal toothing 2A, and an internal gear 4, which is housed in the axial cavity of external gear 2 and has an external toothing 4A, with a different number of teeth, meshing with the toothing of external gear 2 with only partial hydraulic seal.
  • Internal gear 4 is mounted on a pump shaft 6, it is made to rotate by said shaft about a first axis 3 coinciding with the axis of shaft 6, and it makes external gear 2 rotate about a second axis 5, parallel to the first one.
  • the teeth of the two gears define chambers 7 of which the volumes change during rotation and through which oil coming from an axial intake duct 8, formed in a rear base 9 of pump body 10, is compressed before being sent to an axial delivery duct 1 1 , also formed in rear base 9.
  • Arrows Fl and F2 denote the intake and delivery oil flows, and arrow F3 denotes the rotation direction of shaft 6.
  • body 10 On its forward side, body 10 has an axial cavity or regulation chamber 12 in which a moving cover 13, for instance circular, is inserted so as to be axially slidable without rotating, the cover forming the member for regulating the flow rate as the pressure conditions in the lubrication circuit change.
  • Cover 13 may be made of metal, e.g. aluminium, or plastics.
  • Cover 13 has an eccentric through-hole 13 A (fig. 3) through which shaft 6 extends, the shaft penetrating into an axial recess 21 of the front surface of cover 13 and freely rotating in said hole.
  • the axial sliding stroke of cover 13 in chamber 12 is limited backwards by a plane surface of a radial flange 14 of body 10, against which cover 13 abuts in normal operation conditions of pump 1, when no regulation is required, and is limited on the other side by a front base 15 closing chamber 12.
  • the sliding is opposed by a spring 20 eccentrically mounted around the forward end of shaft 6 and abutting at its rear end against the bottom of recess 21 and at its front end against the bottom of an axial recess 22 of front base 15.
  • the depth of recess 22 determines the preload of spring 20.
  • cover 13 On its rear face, cover 13 has a pair of projections or pins 16, advantageously with cylindrical (as shown in the drawing) or conical shape, penetrating into through openings 17 of corresponding shape formed in flange 14. Openings 17 are closed by cover 13 and pins 16 when no flow rate regulation is required, as shown in Fig. 1, whereas they set up a connection for oil recirculation between a delivery chamber 28 and an intake chamber 29 through chamber 12, as shown by arrow F5 in Fig. 4, when the flow rate is to be regulated. Since the flange is part of body 10, and hence is stationary, the engagement of pins 16 into openings 17 prevents cover 13 from rotating. As clearly shown in Fig.
  • pin 16 and opening 17 on the delivery side have smaller diameters than pin 16 and opening 17 on the intake side.
  • the sizes on the delivery side depend on the maximum flow rate to be regulated, whereas the sizes on the intake side are determined so as to ensure a complete pressure release under cover 13.
  • Cover 13 further has, on its side surface, a first step 18 projecting radially outwards and defining a first annular surface exposed to the oil pressure in the lubrication circuit thanks to a first radial passage 24, formed in body 10, which permanently communicates with the main duct for the engine oil and ends into a first chamber 25 defined by step 18 and by a corresponding annular surface on the internal surface of chamber 12.
  • the width of step 18 and the preload of spring 20 determine a first pressure threshold whose attainment starts the sliding of cover 13.
  • cover 13 also has, on its side surface, at least one second step 19 projecting radially outwards and formed between the first step 18 and the front face of cover 13.
  • This second step 19 defines a second annular surface exposed to the oil pressure in the lubrication circuit thanks to a second radial passage 26, also formed in body 10 and ending into a second chamber 27 defined by step 19 and by a corresponding annular surface on the internal surface of chamber 12.
  • the second passage 26 can be put in communication with the main duct for the engine oil by means of a specific command supplied by the control units of the engine itself, as it will be explained later on.
  • a motor vehicle engine 50 where pump 1 is connected, has been schematically shown in Fig. 5.
  • the pump is connected, at the intake side, to oil sump 51 through a pre-filter 52, and, at the delivery side, to main oil duct 53 through main filter 54.
  • An oil pressure detector 55 connected to electronic control unit 56 of the engine, is arranged between filter 54 and main duct 53.
  • Motor 50 uses such oil for lubricating the various moving parts, through dedicated channels branching from main duct 53. According to the invention, two of these channels are connected to radial passages 24, 26 in pump 1.
  • the connection between main duct 53 and the second passage 26 is set up by a valve 57, in particular an electric valve, controlled by control unit 56.
  • An overpressure valve 58 may be connected in parallel to pump 1 in order to recirculate oil directly into sump 51 in case of excessive pressure at the delivery side of the pump.
  • the torque transmitted to shaft 6 is applied to internal gear 4 that, by rotating, makes external gear 2 rotate, thereby allowing the pump to convey from intake chamber 29 to delivery chamber 28 oil sucked from sump 51 and compressed because of the passage through the different chambers 7 and to send such oil to main duct 53.
  • the second step 19 and the second passage 26 are provided, there is a second possibility of flow rate regulation, and consequently of pressure regulation.
  • This second regulation is not automatic, but it is controlled by valve 57.
  • the latter upon receiving a suitable control signal from control unit 56, puts main duct 53 in communication with passage 26, thereby providing a pressure signal (arrow F6) that, when applied to step 19, may cause cover 13 to slide and to create the oil recirculation path even if the pressure threshold necessary to overcome the resistance of spring 20 by acting on step 18 has not been attained.
  • the second step 19 allows having a different pressure regulation threshold, independent of the rotation speed of the motor. In this case, the spring preload is overcome by the sum of the forces applied onto both areas 18, 19.
  • the sliding of cover 13 is opposed by spring 20.
  • the rigidity of a spring is variable within a relatively broad range ( ⁇ 10%) and, therefore, the preload and the compression of the spring are also variable within a broad range. Consequently, the point of intervention of the spring may exhibit an imprecision with respect to the pressure threshold demanded by the motor.
  • the oil pressure at the delivery side can be used to improve the pump structure and the intervention precision. As shown in Fig. 6, this may be obtained by setting up a connection 30 between the pump delivery side and the interior of recess 22, so as to apply the oil pressure against the front face of cover 13. The oil action could not only supplement, but also replace the action of spring 20.
  • pin 16 on the delivery side is in turn exposed to the pressure existing in delivery chamber 28, as shown by arrows F7 in Fig. 6.
  • the free surface of that pin forms therefore a further surface for pressure application, and the pressure in delivery chamber 28 can cause the cover displacement, and the consequent creation of the oil recirculation path, even if the pressure applied to step 18 is not sufficient to overcome the resistance of spring 20.
  • sliding cover 13 acts also as the conventional overpressure valve 58, which therefore can be dispensed with thereby simplifying the structure.
  • the regulating member is directly controlled by the oil pressure in the lubrication circuit, and not by driving members in turn responsive to such a pressure, so that the reaction is faster and the structure is further simplified, whereby costs can be reduced.
  • a contribution to such simplification is also provided by the possibility of exploiting the pressure existing at the delivery side in order to make the regulating member perform the functions of the external overpressure valve.
  • Pump 1 may be used as a self-standing pump or as a part of a combined pump including for instance, in the case of application in the automotive field, a pump for the lubrication oil as one of the subsystems and a vacuum pump or a fuel pump.
  • a combined pump of this kind is shown in Fig. 7, where reference numeral 1 denotes the pump for the lubrication oil according to the invention and reference numeral 100 denotes a second pump.
  • pumps 1 , 100 may be connected in parallel, with a suitable transmission system transmitting the motion to both shafts, or they may be connected in tandem.
  • shaft 6 of pump 1 can be used as a unique integrated shaft extending through both pumps, as shown in Fig. 7.
  • the two shafts could be separate and be connected for instance through an Oldham joint.
  • a method of regulating the flow rate of a pump as described above comprises the steps of:
  • a regulating member 13 which is arranged to axially slide without rotating (since, as said, it is held by pins 16 received in openings 17) and has a first surface 18 responsive to the oil pressure in the lubrication circuit;
  • regulating member 13 also includes the second pressure-responsive surface 19
  • the method also includes the step of applying the pressure existing in the lubrication circuit to surface 19, upon an external command, in order to make regulating member 13 slide independently of whether the first threshold is attained.
  • cover 13 could have more than two annular surfaces for pressure application in order to allow a multi-level regulation.
  • one of the levels will correspond to the regulation depending on the engine speed, whereas the other levels will be actuated by respective external commands.
  • the pump or the motor could be pneumatic machines instead of being hydraulic machines.
  • the individual elements described here can be replaced by functionally equivalent elements.

Abstract

Une machine à fluide à engrenage interne (1), en particulier une pompe destinée au circuit de lubrification d'un moteur thermique de véhicule motorisé, comprend un organe (13) destiné à réguler le débit en fonction des conditions de pression de fluide dans un circuit fluidique auquel est reliée la machine (1). L'organe de régulation (13) est axialement coulissante, sans tourner, dans un siège (12) formé dans le corps (10) de la machine (1) et comporte une première surface (18) pour application de pression, qui est exposée en permanence auxdites conditions de pression et est conçue, lorsqu'un seuil est dépassé, pour provoquer un coulissement de l'organe de régulation (13) afin de créer une voie de recirculation de fluide dans la machine (1). L'invention se rapporte également à un procédé de régulation du débit d'une machine à fluide et à une pompe combinée (1, 100) pour le domaine automobile, utilisant la machine (1) comme pompe destinée au circuit de lubrification.
EP11735549.5A 2010-06-15 2011-06-13 Machine à fluide à engrenage à régulation de débit Withdrawn EP2582981A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITTO2010A000516A IT1401005B1 (it) 2010-06-15 2010-06-15 Macchina fluidica con regolazione della portata
PCT/IB2011/052555 WO2011158167A2 (fr) 2010-06-15 2011-06-13 Machine à fluide à engrenage à régulation de débit

Publications (1)

Publication Number Publication Date
EP2582981A2 true EP2582981A2 (fr) 2013-04-24

Family

ID=43432035

Family Applications (1)

Application Number Title Priority Date Filing Date
EP11735549.5A Withdrawn EP2582981A2 (fr) 2010-06-15 2011-06-13 Machine à fluide à engrenage à régulation de débit

Country Status (3)

Country Link
EP (1) EP2582981A2 (fr)
IT (1) IT1401005B1 (fr)
WO (1) WO2011158167A2 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9163628B2 (en) * 2013-03-11 2015-10-20 Imo Industries, Inc. Self adjusting gear pump
US10337512B2 (en) 2014-08-25 2019-07-02 Carrier Corporation Gear pump with dual pressure relief
US10682748B2 (en) 2017-12-19 2020-06-16 Caterpillar Inc. Auto-lubrication system for a work tool

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH399909A (de) * 1960-04-30 1965-09-30 Danfoss Ved Ing M Clausen Zweistufige Zahnradpumpe
GB1042778A (en) * 1964-06-09 1966-09-14 B & G Hydraulics Ltd Improvements in or relating to reversible gear pumps and motors
US4422834A (en) * 1981-05-07 1983-12-27 Trw Inc. Power steering pump
IT1309094B1 (it) 1999-10-08 2002-01-16 Magneti Marelli Spa Pompa rotativa a cilindrata fissa e portata variabile, particolarmenteper olio.
US7438542B2 (en) * 2005-12-19 2008-10-21 Dana Automotive Systems Group, Llc. Fluid pump assembly
WO2008146352A1 (fr) * 2007-05-28 2008-12-04 Mikuni Corporation Pompe

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
None *
See also references of WO2011158167A2 *

Also Published As

Publication number Publication date
WO2011158167A2 (fr) 2011-12-22
ITTO20100516A1 (it) 2011-12-16
WO2011158167A3 (fr) 2013-03-28
IT1401005B1 (it) 2013-07-05

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