US20190211819A1 - External gear pump for a waste heat recovery system - Google Patents

External gear pump for a waste heat recovery system Download PDF

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Publication number
US20190211819A1
US20190211819A1 US16/328,790 US201716328790A US2019211819A1 US 20190211819 A1 US20190211819 A1 US 20190211819A1 US 201716328790 A US201716328790 A US 201716328790A US 2019211819 A1 US2019211819 A1 US 2019211819A1
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US
United States
Prior art keywords
bearing
external gear
gear pump
shaft
ratio
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.)
Abandoned
Application number
US16/328,790
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English (en)
Inventor
Guido Bredenfeld
Jakob Branczeisz
Marc Laetzel
Matthias Riedle
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.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
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 Robert Bosch GmbH filed Critical Robert Bosch GmbH
Assigned to ROBERT BOSCH GMBH reassignment ROBERT BOSCH GMBH ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: LAETZEL, MARC, BRANCZEISZ, JAKOB, RIEDLE, Matthias, BREDENFELD, GUIDO
Publication of US20190211819A1 publication Critical patent/US20190211819A1/en
Abandoned 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
    • F04C2/12—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
    • F04C2/14—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons
    • F04C2/18—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons with similar tooth forms
    • 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
    • F04C15/0088—Lubrication

Definitions

  • the present invention relates to an external gear pump, in particular one embodied as a feed fluid pump of a waste heat recovery system of an internal combustion engine.
  • the external gear pump according to the invention has the advantage that it can be used for low-viscosity working media that are poor lubricants and can form a hydrodynamic lubricating film in the plain bearings, even for such working media.
  • the bearing service life is thereby significantly increased.
  • the external gear pump has a pump housing.
  • An inlet, an outlet, and a working chamber are formed in the pump housing.
  • a first gear, which is arranged on a first shaft, and a second gear, which is arranged on a second shaft, are arranged in the working chamber in such a way that said first and second gears mesh with each other. Both gears have teeth having a tooth width b.
  • the first shaft is radially supported in at least one plain bearing
  • the second shaft is radially supported in at least one further plain bearing.
  • the plain bearing has a bearing diameter D 61
  • the further plain bearing has a further bearing diameter D 63 .
  • a delivery volume V of a working medium can be conveyed from the inlet to the outlet.
  • the two bearing diameters D 61 , D 63 are designed in such a way that the ratio V/(D 61 2 *b) is ⁇ 1.1 and that the ratio V/(D 63 2 *b) is ⁇ 1.1.
  • the ratio V/(D 61 2 *b) is >0.5, in particular greater than 1.0.
  • the ratio V/(D 63 2 *b) is >0.5, in particular greater than 1.0.
  • the plain bearings can be designed as bearing bores in the pump housing, or in a double bearing seat or bearing bush arranged therein, for example.
  • the delivery volume V is the volume of the working medium delivered to the outlet at typical operating points.
  • the two bearing diameters of the plain bearing and of the further plain bearing are equal.
  • the two plain bearings can be of unitary design. It is furthermore also possible to choose gears of the same size, thus optimizing the efficiency of the external gear pump.
  • the two shafts are each radially supported in two plain bearings, advantageously on both sides of the gears.
  • the external gear pump has a pump housing.
  • An inlet, an outlet, and a working chamber are formed in the pump housing.
  • a first gear, which is arranged on a first shaft, and a second gear, which is arranged on a second shaft, are arranged in the working chamber in such a way that said first and second gears mesh with each other.
  • the first gear has a first tip diameter DK 11 and the second gear has a second tip diameter DK 12 , wherein preferably both tip diameters DK 11 , DK 12 are equal.
  • the first shaft is radially supported in at least one plain bearing and the second shaft is radially supported in at least one further plain bearing.
  • the two shafts are arranged parallel with a center distance a with respect to each other.
  • the plain bearing has a bearing diameter D 61 and the further plain bearing has a further bearing diameter D 63 .
  • the two bearing diameters D 61 , D 63 are designed in such a way that the ratio (DK 11 *a)/D 61 2 is ⁇ 2.5 and that the ratio (DK 12 *a)/D 63 2 is ⁇ 2.5.
  • the ratio is furthermore advantageously (DK 11 *a)/D 61 2 >1.5—in particular greater than 2.0.
  • the ratio (DK 12 *a)/D 63 2 is >1.5—in particular greater than 2.0.
  • the plain bearings can be designed as bearing bores in the pump housing, or in a double bearing seat or bearing bush arranged therein, for example.
  • External gear pumps are very well-suited to use in waste heat recovery systems of internal combustion engines. Waste heat recovery systems of this kind often use low-viscosity working media that are poor lubricants.
  • the external gear pump according to the invention can therefore be used very advantageously in a waste heat recovery system.
  • the waste heat recovery system has a circuit that carries a working medium, wherein the circuit comprises a feed fluid pump, an evaporator, an expansion machine and a condenser in the flow direction of the working medium.
  • the feed fluid pump is embodied as an external gear pump having the features described above.
  • FIG. 1 shows an external gear pump from the prior art in an exploded illustration, wherein only the essential regions are illustrated
  • FIG. 2 shows a schematic sectional illustration through an external gear pump from the prior art
  • FIG. 3 shows an external gear pump in longitudinal section, wherein only the essential regions are illustrated.
  • the external gear pump 1 from the prior art is shown in an exploded illustration in FIG. 1 .
  • the external gear pump 1 comprises a pump housing 2 , a cover 3 and a bottom flange 4 .
  • the cover 3 and the bottom flange 4 are clamped to one another by four screws 5 with the pump housing 2 in between.
  • the pump housing 2 , the cover 3 and the bottom flange 4 delimit a working chamber 6 .
  • a first gear 11 and a second gear 12 are arranged in the working chamber 6 in such a way that said first and second gears mesh with each other.
  • both gears 11 , 12 have a certain number of teeth, each having a tooth width or gear width b.
  • the first gear 11 is secured on a first shaft 21
  • the second gear 12 is secured on a second shaft 22 parallel to the first shaft 21 .
  • the first shaft 21 serves as a drive shaft and is connected to a drive (not illustrated), e.g. a crankshaft of an internal combustion engine.
  • the first shaft 21 projects through the bottom flange 4 .
  • the two shafts 21 , 22 each project through the gear 11 , 12 associated therewith and are connected firmly thereto, in each case by a press fit, for example.
  • the shafts 21 , 22 are supported on both sides of the gears 11 , 12 .
  • Support is provided by two double bearing seats 30 , 40 , wherein the double bearing seats 30 , 40 are arranged in the working chamber 6 : one double bearing seat 30 is arranged adjacent to the bottom flange 4 , and a further double bearing seat 40 is arranged adjacent to the cover 3 .
  • Two bearing bushes 9 are press-fitted in each of the two double bearing seats 30 , 40 .
  • the bearing bushes 9 of the double bearing seat 30 support the two shafts 21 , 22 on the drive side, and the bearing bushes 9 of the further double bearing seat 40 support them on the opposite side of the gears 11 , 12 .
  • the bearing bushes 9 thus form plain bearings for the two shafts 21 , 22 .
  • the two bearing bushes 9 can also be embodied integrally with the double bearing seat 30 . The same also applies to the further double bearing seat 40 .
  • the four bearing bushes 9 each have a radial bearing function and each form a plain bearing with the shaft 21 , 22 associated therewith.
  • the axial bearing function is achieved by means of the two double bearing seats 30 , 40 : for this purpose, double bearing seat 30 has a stop surface 31 on an end face, and the further double bearing seat 40 has a further stop surface 42 on an end face. Both stop surfaces 31 , 42 interact with both gears 11 , 12 . Stop surface 31 supports both gears 11 , 12 in the axial direction oriented toward the bottom flange 4 ; the further stop surface 42 supports both gears 11 , 12 in the axial direction oriented toward the cover 3 .
  • seals 28 , 29 extend approximately in a ring shape over the circumference of the pump housing 28 , 29 and are usually arranged in corresponding grooves.
  • An axial field seal 18 is furthermore arranged between double bearing seat 30 and the bottom flange 4 , and a further axial field seal 19 is arranged between the further double bearing seat 40 and the cover 3 .
  • the two axial field seals 18 , 19 provide axial support for the two double bearing seats 30 , 40 within the pump housing 2 .
  • the end faces or rear sides of the two double bearing seats 30 , 40 are thereby subjected either to the pressure level of the pressure zone or to the pressure level of the suction zone, depending on the angle of rotation.
  • FIG. 2 shows the principle of action of the external gear pump 1 known from the prior art in a schematic sectional illustration.
  • An inlet 2 a and an outlet 2 b, which open into the working chamber 6 on opposite sides, are formed in the pump housing 2 .
  • a delivery volume V of the working medium is thus conveyed from the inlet 2 a to the outlet 2 b on the housing wall of the pump housing 2 between the teeth of the two gears 11 , 12 .
  • the delivery volume V corresponds to the volume delivered in rated operation of the external gear pump 1 , i.e. to the volume delivered at significant operating points.
  • a specific delivery volume V spec V/b is thus obtained.
  • the second pressure level of the pressure zone depends on the following flow topology, e.g. on a restriction.
  • the tip diameter DK 11 of the first gear 11 and the tip diameter DK 12 of the second gear 12 are furthermore illustrated, as is the center distance a between the two shafts 21 , 22 .
  • the two tip diameters DK 11 , DK 12 are equal and the two gears 11 , 12 have the same number of teeth.
  • FIG. 3 shows a cross section of an external gear pump 1 according to the invention in the region through the longitudinal axes of the two shafts 21 , 22 , which are arranged parallel to one another at a center distance a.
  • the diameters of the plain bearings 61 , 62 , 63 , 64 of the two shafts 21 , 22 are made significantly larger than in the case of conventional external gear pumps.
  • the external gear pump 1 according to the invention is suitable for low-viscosity (e.g. for viscosities ⁇ 2 mm 2 /s) and working media that are poor lubricants.
  • the external gear pump 1 according to the invention is therefore particularly well-suited for use in waste heat recovery systems of internal combustion engines.
  • the gear pair i.e. the two gears 11 , 12
  • the gear pair are supported by means of plain bearings 61 , 62 , 63 , 64 .
  • support is provided in two two-part double bearing seats 30 , 40 .
  • the two double bearing seats 30 , 40 can also be of integral construction.
  • bearing bushes as depicted in FIG. 1 .
  • double bearing seat 30 and the further double bearing seat 40 can also be of different construction, as before.
  • Double bearing seat 30 is supported via the axial field seal 18 on the bottom flange 4
  • the further double bearing seat 40 is supported via the further axial field seal 19 on the cover 3 .
  • Both double bearing seats 30 , 40 are thus supported in the pump housing 2 via the two axial field seals 18 , 19 and the shafts 21 , 22 arranged therebetween and via gears 11 , 12 .
  • a through-drive shaft opening 15 is formed in the bottom flange 4 .
  • the drive shaft of the external gear pump 1 in this case the first shaft 21 , can be passed out of the pump housing 2 and coupled to a drive, e.g. a coupling or a belt.
  • bearing bores 51 , 52 , 53 , 54 are formed in the double bearing seats 30 , 40 , with the result that the first shaft 21 is supported by means of the first bearing bore 51 and by means of the second bearing bore 52 , and with the result that the second shaft 22 is supported by means of the third bearing bore 53 and by means of the fourth bearing bore 54 .
  • Three bearing bores 52 , 53 , 54 are embodied as blind bores, while the first bearing bore 51 is embodied as a through bore, thus enabling the first shaft 21 , which is embodied as a drive shaft, to be passed out of double bearing seat 30 .
  • the four bearing bores 51 , 52 , 53 , 54 each form a plain bearing 61 , 62 , 63 , 64 for the shafts 21 , 22 .
  • the first shaft 21 is supported in two plain bearings 61 , 62 , wherein the two plain bearings 61 , 62 are arranged on opposite sides of the first gear 11 when viewed in the axial direction.
  • the second shaft 22 is supported in two further plain bearings 63 , 64 , wherein the two further plain bearings 63 , 64 are arranged on opposite sides of the second gear 12 when viewed in the axial direction.
  • the external gear pump 1 has just one plain bearing for each shaft 21 , 22 . That is to say, for example, the first shaft 21 is then radially supported only by plain bearing 61 , and the second shaft 22 is radially supported only by the further plain bearing 63 within the pump housing 2 .
  • the plain bearings 61 , 62 , 63 , 64 unlike the conventional designs, are provided with particularly large bearing diameters D 61 , D 62 , D 63 , D 64 .
  • the individual bearing diameters D 61 , D 62 , D 63 , D 64 are configured in such a way that:
  • the bearing diameters D 61 , D 62 , D 63 , D 64 of the plain bearings 61 , 62 , 63 , 64 should be configured in relation to the tip diameter DK 11 , DK 12 of the two gears 11 , 12 and in relation to the center distance a of the two shafts 21 , 22 relative to one another.
  • the peripheral speed of the cylindrical contact surfaces of the shafts 21 , 22 in the plain bearings 61 , 62 , 63 , 64 is thereby increased to such an extent that the radial sliding support with a given low-viscosity working medium and a given, relatively low delivery volume V of the external gear pump 1 functions in the hydrodynamic mode, that is to say a lubricating film can build up between the shafts 21 , 22 and the plain bearings 61 , 62 , 63 , 64 .
  • the aim is to make the bearing diameter D 61 , D 62 , D 63 , D 64 of the plain bearings 61 , 62 , 63 , 64 as large as possible, and therefore a tooth system of the two gears 11 , 12 is chosen which, on the one hand, still rolls cleanly in mechanical terms and allows adequate hydraulic seals with respect to the pump housing 2 , the cover 3 and the bottom flange 4 without producing an excessive delivery volume V, wherein the delivery volume V should be suitable, in particular, for a waste heat recovery system.
  • the object of designing the external gear pump 1 in such a way that the sliding speed between the shaft 21 , 22 and the plain bearings 61 , 62 , 63 , 64 is very greatly increased does not arise in the project planning for a conventional external gear pump corresponding to the prior art for the usual higher-viscosity working media.
  • a hydrodynamic lubricating film would nevertheless be established in the contact locations of the plain bearings.
  • the invention is defined in such a way that a ratio of the specific delivery volume V spec of the delivery tooth system [mm 3 delivery volume V per millimeter of gear width b] in relation to the square of the bearing diameter D of the plain bearings is less than 1.1.
  • Pumps according to the prior art generally have a ratio of 2 and above in this respect.
  • another ratio of the product of the tip diameter DK and the center distance a divided by the square of the bearing diameter D is less than 2.5.
  • Pumps according to the prior art generally have a further ratio of this kind of 3 and above.
  • the external gear pump 1 according to the invention is arranged in a waste heat recovery system of an internal combustion engine.
  • the internal combustion engine is supplied with oxygen via an air inlet; the exhaust gas expelled after the combustion process is discharged from the internal combustion engine through an exhaust line.
  • the waste heat recovery system has a circuit that carries a working medium, which comprises a feed fluid pump, an evaporator, an expansion machine and a condenser in the flow direction of the working medium.
  • the working medium can be fed into the circuit from a collecting tank and a valve unit via a branch line as required.
  • the collecting tank can also be incorporated into the circuit.
  • the evaporator is connected to the exhaust line of the internal combustion engine and therefore uses the heat energy of the exhaust gas of the internal combustion engine.
  • Liquid working medium is fed into the evaporator by the feed fluid pump, optionally from the collecting tank, and is evaporated there by the heat energy of the exhaust gas of the internal combustion engine.
  • the evaporated working medium is then expanded in the expansion machine, releasing mechanical energy, e.g. to a generator (not illustrated) or a transmission (not illustrated).
  • the working medium is then condensed again in the condenser and returned to the collecting tank or fed to the feed fluid pump.
  • the feed fluid pump of the waste heat recovery system is an external gear pump 1 according to one of the above embodiments.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Details And Applications Of Rotary Liquid Pumps (AREA)
  • Rotary Pumps (AREA)
US16/328,790 2016-08-29 2017-06-20 External gear pump for a waste heat recovery system Abandoned US20190211819A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE102016216159.8A DE102016216159A1 (de) 2016-08-29 2016-08-29 Außenzahnradpumpe für ein Abwärmerückgewinnungssystem
DE102016216159.8 2016-08-29
PCT/EP2017/065067 WO2018041434A1 (de) 2016-08-29 2017-06-20 AUßENZAHNRADPUMPE FÜR EIN ABWÄRMERÜCKGEWINNUNGSSYSTEM

Publications (1)

Publication Number Publication Date
US20190211819A1 true US20190211819A1 (en) 2019-07-11

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Family Applications (1)

Application Number Title Priority Date Filing Date
US16/328,790 Abandoned US20190211819A1 (en) 2016-08-29 2017-06-20 External gear pump for a waste heat recovery system

Country Status (4)

Country Link
US (1) US20190211819A1 (de)
CN (1) CN109642567A (de)
DE (1) DE102016216159A1 (de)
WO (1) WO2018041434A1 (de)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113090672A (zh) * 2021-03-26 2021-07-09 龙岩市金山粉末冶金有限公司 一种齿轮泵的滑动轴座及其制造工艺

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE29516780U1 (de) * 1995-10-24 1995-12-07 Truninger Ag Zahnradpumpe oder -motor
DE19924057A1 (de) * 1999-05-26 2000-11-30 Bosch Gmbh Robert Zahnradmaschine (Pumpe oder Motor)
WO2006090495A1 (ja) * 2005-02-24 2006-08-31 Shimadzu Corporation 歯車ポンプ
EP1852612B1 (de) * 2005-02-24 2017-07-05 Shimadzu Mectem, Inc. Zahnradpumpe
CN2839647Y (zh) * 2005-10-19 2006-11-22 玉环恒力泵业有限公司 齿轮泵
DE102009045030A1 (de) 2009-09-25 2011-03-31 Robert Bosch Gmbh Zahnradpumpe mit Elektromotor
DE102013205648A1 (de) 2012-12-27 2014-07-03 Robert Bosch Gmbh System zur Energierückgewinnung aus einem Abwärmestrom einer Brennkraftmaschine
JP3188863U (ja) * 2013-11-27 2014-02-13 住友精密工業株式会社 液圧装置
EP3114350B1 (de) * 2014-03-07 2021-06-30 Nichols Portland, LLC Drei-getriebe-pumpensystem für niedrigviskose flüssigkeiten
CN204941925U (zh) * 2015-08-31 2016-01-06 张军民 高压齿轮水泵

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Publication number Publication date
DE102016216159A1 (de) 2018-03-01
WO2018041434A1 (de) 2018-03-08
CN109642567A (zh) 2019-04-16

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