EP2317144A2 - Zahnrad für eine hydraulische Zahnradpumpe - Google Patents

Zahnrad für eine hydraulische Zahnradpumpe Download PDF

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Publication number
EP2317144A2
EP2317144A2 EP10189404A EP10189404A EP2317144A2 EP 2317144 A2 EP2317144 A2 EP 2317144A2 EP 10189404 A EP10189404 A EP 10189404A EP 10189404 A EP10189404 A EP 10189404A EP 2317144 A2 EP2317144 A2 EP 2317144A2
Authority
EP
European Patent Office
Prior art keywords
gear
tooth
gears
teeth
hydraulic
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Withdrawn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
EP10189404A
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English (en)
French (fr)
Other versions
EP2317144A3 (de
Inventor
Mario Antonio Morselli
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.)
Settima Meccanica Srl
Original Assignee
Settima Meccanica Srl
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Filing date
Publication date
Application filed by Settima Meccanica Srl filed Critical Settima Meccanica Srl
Publication of EP2317144A2 publication Critical patent/EP2317144A2/de
Publication of EP2317144A3 publication Critical patent/EP2317144A3/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Withdrawn legal-status Critical Current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
    • F04C2/084—Toothed wheels
    • 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

Definitions

  • the present invention relates to a gear of the type having a profile suitable for meshing with semi-encapsulation in a hydraulic gear apparatus.
  • Typical examples of hydraulic gear apparatuses in which the gears of the present invention can be used in an optimum manner, and to which specific reference will be made in the course of the present description, are positive-displacement rotary gear pumps, but the gears of the present invention may also be used analogously in hydraulic gear motors, which are therefore regarded as being included in the scope of the present invention.
  • Positive-displacement rotary gear pumps are generally composed of two gears which in the majority of cases are of the type having straight teeth and one of which, referred to as the driving gear, is connected to a control shaft and drives the other gear, referred to as the driven gear, in rotation.
  • a particular disadvantage of the above-mentioned gear pumps of the traditional type, which generally have an involute tooth profile, is the fact that the pumped fluid is encapsulated, that is to say, trapped, and compressed or at any rate subjected to variations in volume in the enclosed spaces between the profiles of the teeth in the meshing zone, thus giving rise to detrimental and uncontrolled local stress peaks which cause direct operating noise.
  • ripple noise also known in addition to the direct operating noise indicated above is the problem resulting from the phenomenon of irregularity, or ripple, in the transfer of fluid which involves indirect operating noise, known as ripple noise, associated with the flow pulsation, and therefore pressure pulsation, in the consumer circuit.
  • ripple noise indirect operating noise
  • oscillations in the flow of fluid generate a pulsating wave which, through the fluid itself, is transmitted to the surroundings and, in particular, to the walls of the pump, to the tubing and to the delivery ducts.
  • the noise induced may even reach unpredictable levels if the above-mentioned bodies start to resonate at the frequency of oscillation or ripple.
  • Some of those solutions relate to pumps with traditional toothing, with mostly, but not necessarily, involute tooth flank profiles, with straight, or much more rarely, helical toothing, with clearance (that is to say, with single contact of a tooth of one gear with a corresponding tooth of the other gear) or theoretically without clearance (that is to say, with double contact, where both of the tooth flanks are theoretically always in mesh, as in the pump manufactured by Bosch Rexroth AG which is known by the trade name SILENCE, or the pump manufactured by Casappa S.p.A. which is known by the trade name WHISPER).
  • the fluid trapped between the teeth is at least in part "discharged", that is to say, evacuated, through suitable outlets or pockets or ducts formed on the faces of the lateral shims, otherwise referred to as supports or bushes, of the gears, that is to say, on the walls which face the flat lateral ends of the gears, and which enable the encapsulated volume of fluid to be discharged (or admitted) towards the appropriate opening or port, at high or low pressure, respectively.
  • the invention relates to a gear having a plurality of teeth suitable for meshing with the teeth of another, corresponding, gear, the profile of each tooth of the gear, in cross-section, being defined in the claims which follow.
  • the profile of at least one tooth of one of the two rotors is defined by a spline function passing through a plurality of node points having predetermined coordinates, with a tolerance of ⁇ 1/15, more preferably ⁇ 1/20, and even more preferably ⁇ 1/30 of the height of the tooth of the gear on the theoretical profile defined by the plurality of preferred node points.
  • the node points are defined by a pair of values ⁇ X', Y' ⁇ expressed in a system of cartesian coordinates having their origin in the centre of the pitch circle of the gear.
  • the origin of the system of x, y coordinates is the line of the axis of rotation of the gear on a plane perpendicular to that axis, which precisely coincides with the centre of the pitch circle of the said gear.
  • spline function refers generally to any spline function which does not introduce errors, or to a smoothing spline having a sufficiently small smoothing parameter not to introduce significant errors with respect to the node points.
  • the spline function adopted is a natural cubic spline function, that is to say, a third-degree interpolating natural spline function.
  • the gears are advantageously helical and the face contact ratio of the helical toothing is from 0.4 to 1.2, preferably from 0.5 to 1.2, more preferably from 0.6 to 1.2, more preferably from 0.7 to 1.1, more preferably from 0.8 to 1.1, and even more preferably from 0.9 to 1.
  • the face contact ratio of the helical toothing is equal to or close to unity.
  • a gear according to the present invention has a ratio of the sizes of the face width and the pitch diameter of from 0.5 to 2, preferably from 0.6 to 1.8, more preferably from 0.65 to 1.5, and even more preferably from 0.7 to 1.25.
  • the ratio of the sizes of the face width and the pitch diameter is close to unity.
  • the present invention relates also to a hydraulic gear apparatus comprising a pair of meshing gears having a tooth profile of the type indicated above.
  • this hydraulic apparatus may be a hydraulic pump or a hydraulic motor.
  • a gear 10 according to the present invention (only one sector of which is illustrated in the Figure) is to mesh with another, corresponding, gear (not shown) for use in a positive-displacement rotary pump, preferably of the type for high operating pressures, where the pressure differentials between suction and delivery are greater than a few tens of bar, more particularly greater than approximately 50 bar, and even more particularly greater than approximately 80-100 bar.
  • the gear 10 comprises a plurality of teeth 11 having a height H and a profile suitable for meshing with semi-encapsulation with the teeth of the other, corresponding, gear.
  • the profile of the teeth 11 cannot be described as a succession of simple geometric curves but can be defined by a natural cubic spline function (although it is possible, in the terms already indicated above, to use other spline or smoothing spline functions) passing through a plurality of node points 12 defined by pairs of values expressed in a system of cartesian coordinates having their origin in the centre O of the pitch circle 13 of the gear 10.
  • the resultant profiles must be conjugate, if not exactly from an analytical point of view, at least from a practical point of view, that is to say, the profiles must be suitable for meshing correctly in actual use in the hydraulic apparatuses to which the present invention relates. It is worth pointing out in this connection that, even in the current art, traditional "involute” gears are often not produced in accordance with “pure” involute geometry but with small differences or variations with respect thereto, giving rise to profiles which are variously referred to as K profile, tip relief, etc.
  • the single Figure shows a comparison between the profile of the tooth 11 of a gear produced in accordance with the invention, and the profile of a tooth D of the prior art which is drawn with a dot-dash line and which is designed in accordance with the concept of "non-encapsulation". It can be seen immediately that the tooth 11 is markedly taller than the tooth D of the prior art and it will therefore be appreciated that a gear having teeth 11 produced in accordance with the principle of "semi-encapsulation" of the present invention leads to a greater volumetric efficiency than do the gears produced in accordance with the principle of "non-encapsulation", if for no other reason than that it is possible to adopt, for the same flow rate and space requirement, a larger number of teeth.
  • a gear having a number of teeth equal to seven has a theoretical tooth profile defined by a natural cubic spline function (which, if necessary, may be replaced by another spline or smoothing spline function) passing through a plurality of node points defined by a pair of values ⁇ X',Y' ⁇ expressed in a system of cartesian coordinates having their origin in the centre O of the pitch circle P of the gear.
  • the coordinates of the node points are homothetic to the pairs of values ⁇ X,Y ⁇ of the list reproduced in the following Table 1.
  • a gear having a number of teeth equal to eight has a theoretical tooth profile defined by a natural cubic spline function (which, if necessary, can be replaced by another spline or smoothing spline function) passing through a plurality of node points defined by a pair of values ⁇ X',Y' ⁇ expressed in a system of cartesian coordinates having their origin in the centre O of the pitch circle P of the gear.
  • the coordinates of the node points are homothetic to the pairs of values ⁇ X,Y ⁇ of the list reproduced in the following Table 2.
  • a gear having a number of teeth equal to nine has a theoretical tooth profile defined by a natural cubic spline function (which, if necessary, can be replaced by another spline or smoothing spline function) passing through a plurality of node points defined by a pair of values ⁇ X',Y' ⁇ expressed in a system of cartesian coordinates having their origin in the centre O of the pitch circle P of the gear.
  • the coordinates of the node points are homothetic to the pairs of values ⁇ X,Y ⁇ of the list reproduced in the following Table 3.
  • a gear having a number of teeth equal to ten has a theoretical tooth profile defined by a natural cubic spline function (which, if necessary, can be replaced by another spline or smoothing spline function) passing through a plurality of node points defined by a pair of values ⁇ X',Y' ⁇ expressed in a system of cartesian coordinates having their origin in the centre O of the pitch circle P of the gear.
  • the coordinates of the node points are homothetic to the pairs of values ⁇ X,Y ⁇ of the list reproduced in the following Table 4.
  • the production tolerance (and the design) of the gears must be such as to ensure that the profile of the cut teeth is within a tolerance band of ⁇ 1/15, more preferably 1/20, and even more preferably ⁇ 1/30 of the height of the gear tooth.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Rotary Pumps (AREA)
  • Lubricants (AREA)
EP10189404A 2009-10-30 2010-10-29 Zahnrad für eine hydraulische Zahnradpumpe Withdrawn EP2317144A3 (de)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
ITBO2009A000714A IT1398817B1 (it) 2009-10-30 2009-10-30 Ruota dentata con profilo atto ad ingranare con semi-incapsulamento in un'apparecchiatura idraulica ad ingranaggi

Publications (2)

Publication Number Publication Date
EP2317144A2 true EP2317144A2 (de) 2011-05-04
EP2317144A3 EP2317144A3 (de) 2012-12-26

Family

ID=42154360

Family Applications (1)

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EP10189404A Withdrawn EP2317144A3 (de) 2009-10-30 2010-10-29 Zahnrad für eine hydraulische Zahnradpumpe

Country Status (6)

Country Link
US (1) US20110103993A1 (de)
EP (1) EP2317144A3 (de)
CN (1) CN102052447B (de)
BR (1) BRPI1003887A2 (de)
IT (1) IT1398817B1 (de)
TW (1) TW201124653A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106015516A (zh) * 2016-05-24 2016-10-12 北京航空航天大学 一种基于b样条啮合线的内啮合齿轮齿形设计方法

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9404366B2 (en) * 2009-10-30 2016-08-02 Settima Meccanica S.R.L. Gear wheel with profile capable of meshing with semi-encapsulation in a geared hydraulic apparatus
CN102322419B (zh) * 2011-09-30 2016-01-20 浙江奥威特液压机械有限公司 螺杆泵
US10527149B2 (en) 2015-12-11 2020-01-07 Gear Innovations Llc Conjugate gears with continuous tooth flank contact
DE102017221736B4 (de) * 2017-12-03 2021-11-25 Audi Ag Verfahren zur Akustikbeeinflussung von Zahnrädern
DE102023117249A1 (de) * 2023-06-29 2025-01-02 Hirschvogel Holding GmbH Differentialkegelrad, Kegelraddifferential sowie Verfahren zum umformtechnischen Erzeugen eines Differentialkegelrads

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2159744A (en) 1936-08-26 1939-05-23 Brown & Sharpe Mfg Gear pump
US3164099A (en) 1961-08-09 1965-01-05 Iyoi Hitosi Toothed profiles of rotors of gear pump
US3209611A (en) 1961-05-02 1965-10-05 Iyoi Hitosi Teeth profiles of rotors for gear pumps of rotary type
ITBO950095A1 (it) * 1995-03-10 1996-09-10 Stem Numerical Engineering Srl Profili per rotori di compressori roots
EP0769104A1 (de) 1994-07-07 1997-04-23 David Brown Hydraulics Limited Schrägverzahnte zahnradpumpe oder-motor
EP1132618A2 (de) 2000-03-08 2001-09-12 Mario Antonio Morselli Drehkolben-Verdrängungspumpe mit Schraubenrotoren
EP1371848A1 (de) * 2002-06-12 2003-12-17 Mario Antonio Morselli Zahnradpumpe mit Splinefunktion erzeugtem Zahnradprofil
WO2008111017A1 (en) 2007-03-14 2008-09-18 Settima Meccanica S.R.L. Improved geared hydraulic apparatus

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1195541A4 (de) * 1999-06-14 2004-05-19 Wei Xiong Getriebe und fluidmaschine mit einem zahnradpaar

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2159744A (en) 1936-08-26 1939-05-23 Brown & Sharpe Mfg Gear pump
US3209611A (en) 1961-05-02 1965-10-05 Iyoi Hitosi Teeth profiles of rotors for gear pumps of rotary type
US3164099A (en) 1961-08-09 1965-01-05 Iyoi Hitosi Toothed profiles of rotors of gear pump
EP0769104A1 (de) 1994-07-07 1997-04-23 David Brown Hydraulics Limited Schrägverzahnte zahnradpumpe oder-motor
ITBO950095A1 (it) * 1995-03-10 1996-09-10 Stem Numerical Engineering Srl Profili per rotori di compressori roots
EP1132618A2 (de) 2000-03-08 2001-09-12 Mario Antonio Morselli Drehkolben-Verdrängungspumpe mit Schraubenrotoren
EP1371848A1 (de) * 2002-06-12 2003-12-17 Mario Antonio Morselli Zahnradpumpe mit Splinefunktion erzeugtem Zahnradprofil
US6769891B2 (en) 2002-06-12 2004-08-03 Mario Antonio Morselli Rotary positive-displacement pump with meshing gear wheels without encapsulation, and gear wheel for such a positive-displacement pump
EP1371848B1 (de) 2002-06-12 2006-01-04 Mario Antonio Morselli Zahnradpumpe mit Splinefunktion erzeugtem Zahnradprofil
WO2008111017A1 (en) 2007-03-14 2008-09-18 Settima Meccanica S.R.L. Improved geared hydraulic apparatus

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
"A Rational Procedure for the Preliminary Design of Minmum Volume Gears", 1 January 1992, AMERICAN GEAR MANUFACTURERS ASSOCIATION, article "A Rational Procedure for the Preliminary Design of Minmum Volume Gears", pages: 1 - 44, XP055028077 *
FLUIDES & TRANSMISSIONS, no. 75, April 2005 (2005-04-01), pages 34 - 37
MORSELLI MARIO ANTONIO: "Rumorosita meccanica e idraulica delle pompe ad ingranaggi", OLEODINAMICA PNEUMATICA, January 2005 (2005-01-01), pages 54 - 59

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106015516A (zh) * 2016-05-24 2016-10-12 北京航空航天大学 一种基于b样条啮合线的内啮合齿轮齿形设计方法
CN106015516B (zh) * 2016-05-24 2018-06-12 北京航空航天大学 一种基于b样条啮合线的内啮合齿轮齿形设计方法

Also Published As

Publication number Publication date
ITBO20090714A1 (it) 2011-04-30
TW201124653A (en) 2011-07-16
CN102052447B (zh) 2017-04-12
BRPI1003887A2 (pt) 2012-06-12
US20110103993A1 (en) 2011-05-05
CN102052447A (zh) 2011-05-11
IT1398817B1 (it) 2013-03-21
EP2317144A3 (de) 2012-12-26

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