Mechanical combustion-engine-driven fluid pump [US10024322B2]

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Note: Within nine months of the publication of the mention of the grant of the European patent in the European Patent Bulletin, any person may give notice to the European Patent Office of opposition to that patent, in accordance with the

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EUROPEAN PATENT SPECIFICATION

(45) Date of publication and mention of the grant of the patent:

28.06.2017 Bulletin 2017/26

(21) Application number: 12750762.2 (22) Date of filing: 23.08.2012

(51) Int Cl.:

F16D 37/02(2006.01) _{F16D 27/01}(2006.01)

(86) International application number:

PCT/EP2012/066465

(87) International publication number:

WO 2014/029446 (27.02.2014 Gazette 2014/09)

(54) MECHANICAL COMBUSTION-ENGINE-DRIVEN FLUID PUMP

DURCH EINEN VERBRENNUNGSMOTOR ANGETRIEBENE MECHANISCHE FLÜSSIGKEITSPUMPE

POMPE À FLUIDE MÉCANIQUE ENTRAÎNÉE PAR MOTEUR À COMBUSTION (84) Designated Contracting States:

AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(43) Date of publication of application:

01.07.2015 Bulletin 2015/27

(73) Proprietor: Pierburg Pump Technology GmbH

41460 Neuss (DE)

(72) Inventors:

• SQUARCINI, Raffaele I-57125 Livorno (IT) • BARTALESI, Elisa

I-53034 Colle Di Val d’Elsa Siena (IT) • ARMENIO, Giacomo

I-57128 Livorno (IT) • BUCHHI, Francesco

56023 Cascina (PI) (IT) • RIZZO, Rocco I- 56123 Pisa (IT) • MUSOLINO, Antonio I- 56100 Pisa (IT) • FORTE, Paola I- 56123 Pisa (IT) • FRENDO, Francesco I- 55049 Viareggio (IT) • FRANCESCHINI, Alessandro

I- 55012 Capannori Lucca (IT) • BUCCHI, Francesco

I-56023 Pisa (PI) (IT)

(74) Representative: Patentanwälte ter Smitten

Eberlein-Van Hoof Rütten Partnerschaftsgesellschaft mbB Burgunderstraße 29 40549 Düsseldorf (DE) (56) References cited: DE-A1-102007 020 867 FR-A- 1 101 667 GB-A- 708 557 US-A1- 2009 266 666

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5 10 15 20 25 30 35 40 45 50 55 Description

[0001] The invention refers to a mechanical fluid pump

which is driven by an internal combustion engine and is providing a liquid, pressurized gas or vacuum to an au-tomotive unit.

[0002] The fluid pump can be a lubricant pump, a

cool-ant pump, a vacuum pump or a pump providing pressu-rized liquid or gas, for example pressupressu-rized air. The me-chanical fluid pump is not driven by an electric motor but is directly connected to the combustion engine. As a con-sequence, the rotational speed of the fluid pump is pro-portional to the rotational speed of the combustion engine so that the fluid pump is always rotating even if there is no need for fluid supply or for a suction activity to create a vacuum.

[0003] In US 7 422 093 B2 a fluid pump for providing

a pressurized liquid for a hydraulic power steering is de-scribed. The fluid pump is provided with a magneto-rhe-ological clutch so that the pump performance can be con-trolled depending on the fluid demand and pressure de-mand of the power steering.

[0004] A risk of failure is not acceptable for vital fluid

pumps, such as a lubricant pump, a coolant pump or a vacuum pump for a pneumatic brake assistance unit. The fluid pump including the clutch should be as compact as possible. In many applications a relatively high torque has to be coupled by the clutch.

[0005] DE 10 2007 020 867 A1 discloses a

magneto-rheological multi-disk clutch which is actuated by an elec-tromagnet. Alternatively, a permanent magnet can be provided so that the distance of the permanent magnet to the disk clutch determines the grade of torque trans-mission.

[0006] Document GB 708557 discloses a clutch or

brake arrangement with two clutch elements. One clutch element is axially shiftable so that the axial distance of the two clutch elements can be changed to engage or disengage the clutch by using a magneto-rheological powder.

[0007] It is an object of the invention to provide a

me-chanical combustion-engine-driven fluid pump with a compact magneto-rheological clutch.

[0008] This object is solved with a mechanical

com-bustion-engine-driven fluid pump with the features of claim 1.

[0009] The fluid pump according to the invention is

pro-vided with an input shaft which is directly driven by the combustion engine and with a pumping unit with a pump rotor for pumping the fluid which can be a liquid or a gas. The term "directly driven" is to be understood as that there is no disengagable clutch between the rotational element of the engine and the input shaft of the pump. The input shaft of the pump can be driven by the engine via a belt, gear wheels or by a direct coupling with the camshaft or the crankshaft of the engine.

[0010] The clutch is realized as a magneto-rheological

clutch in the form of a multi-disc clutch. The clutch is

provided with at least two radial input clutch disks and at least two radial output clutch disks, whereby the clutch disks define numerous radial clutch liquid gaps between them. The multi-disk configuration of the magneto-rheo-logical clutch allows a compact diameter of the clutch and to transfer high torques from the clutch input to the clutch output.

[0011] The radial clutch liquid gaps arranged axially

between the input clutch disks and the output clutch disks are filled with a magneto-rheological clutch liquid which has a relatively high viscosity when a magnetic field is present and which has a relatively low viscosity when no magnetic field is present. The term liquid in context with the magneto-rheological liquid is not to be taken literally but is to be understood as a kind of a magneto-rheological fluid which can also be somehow solid when activated by a magnetic field. The magnetic field for increasing the viscosity of the magneto-rheological clutch liquid is not generated by an electromagnetic means but is generated by a permanent magnet element which is shiftable be-tween a disengaged position in which the permanent magnet element’s magnetic field penetration flux in the clutch liquid gaps is low and an engaged position in which the magnetic field flux penetration in the clutch liquid gaps is high. In its engaged position, the permanent magnet is positioned close to the clutch liquid gaps, and in the disengaged position, the permanent magnet is more dis-tant and remote from the clutch liquid gaps. The perma-nent magnet element can be provided co-rotating with the input clutch disks so that the permanent magnet el-ement is always rotating with the rotational speed of the input shaft.

[0012] The permanent magnet element is provided

shiftable in axial direction.

[0013] The permanent magnet element is moved

be-tween the engaged and the disengaged position by a separate magnet element actuator.

[0014] Since the magnetic field for penetrating the

clutch liquid gaps and the magneto-rheological clutch liq-uid therein is not generated by an electromagnet, the magneto-rheological clutch can generally also be en-gaged if the control means of the pump and for the clutch actuation fails.

[0015] Generally, the magneto-rheological

eddy-cur-rent clutch can also be combined with other automotive devices around or not around the engine, or even outside automotive applications.

[0016] The magnet chamber is provided radially

in-wardly of the clutch disks. The permanent magnet ele-ment is provided shiftable in the magnet chamber be-tween the engaged and the disengaged position. The clutch disks are arranged radially outwardly and radially adjacent to the magnet chamber. Preferably, the radial planes of the clutch liquid gaps intersect with the perma-nent magnet element in its engaged position. In other words, the magnetic field of the engaged permanent magnet element generally radially penetrates the fluid liquid gaps. This arrangement allows a homogenous

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etration of the radial fluid liquid gaps when the permanent magnet element is in its engaged position.

[0017] Preferably, the permanent magnet element is

magnetized in circumferential direction.

[0018] The permanent magnet element can preferably

be pretensioned by a passive pretension element into its engaged position. If the actuator fails, the pretension el-ement pushes the permanent magnet elel-ement into the engaged position. This arrangement makes the clutch concept totally failsafe. The passive pretension element can be, for example, a spring or another permanent mag-net. However, the passive pretension element does not need any external energy to provide the pretension force.

[0019] The magnet chamber is the chamber wherein

the permanent magnet element is arranged shiftable be-tween its engaged and disengaged position. Preferably, a longitudinal engagement section of the magnet cham-ber wall intersecting with the planes of the clutch liquid gaps is made out of a non-ferromagnetic material. As a consequence, the magnetic field of the permanent mag-net element is radially not shielded in the engagement section of the magnet chamber wall so that the magnetic field of the permanent magnet element penetrates the clutch liquid gaps without any relevant weakening. The radial thickness of the magnet chamber wall in the en-gagement section should be as small as possible to min-imize the magnetic gap between the permanent magnet element and the clutch liquid gaps.

[0020] According to a preferred embodiment, the

lon-gitudinal disengagement section of the magnet chamber wall is made of a ferromagnetic material to shield the magnetic field of the permanent magnet element with respect to the clutch liquid gaps in the disengaged posi-tion of the permanent magnet element. The better the magnetic shielding of the permanent magnet in its dis-engaged position is, the less torque is transferred be-tween the input clutch disks and the output clutch disks in the disengaged position of the permanent magnet el-ement.

[0021] Preferably, the actuator can be provided as a

vacuum actuator. The vacuum actuator is magnetically neutral and does not generate any electromagnetic field which could penetrate the clutch liquid gap filled with the magneto-rheological clutch liquid.

[0022] One embodiment of the invention is described

with reference to the enclosed drawings, wherein figure 1 shows a mechanical combustion-engine-driven fluid pump with a magneto-rheological multi-disc clutch in longitudinal cross-section in the en-gaged state, and

figure 2 shows the fluid pump of figure 1 in the dis-engaged state.

[0023] The figures 1 and 2 show a typical automotive

arrangement consisting of an internal combustion engine 12 and a mechanical fluid pump 10 directly driven by the

combustion engine 12. The fluid pump 10 can be de-signed as a vacuum pump 10, but also can be provided as a lubricant pump, coolant pump etc. The combustion engine 12 is mechanically directly connected to an input shaft 20 of a clutch 16 of the vacuum pump 10 so that the input shaft 20 is always co-rotating with a rotational speed being directly proportional to the rotational speed of the combustion engine 12.

[0024] The clutch 16 is arranged between the input

shaft 20 and an output shaft 21 and is designed as a magneto-rheological multi-disc clutch 16. The clutch 16 connects the input shaft 20 with the output shaft 21 in the engaged clutch state, as shown in figure 1, and dis-connects the output shaft 21 from the input shaft 20 in the disengaged state, as shown in figure 2. The output shaft 21 of the clutch 16 is directly coupled to a vacuum pumping unit 18 with a pump rotor 19. The clutch 16 is provided with four radially input clutch disks 62 and with five radial output clutch disks 64. All clutch disks 62, 64 lie in a radial plane, respectively. Between the clutch disks 62, 64 eight radial clutch liquid gaps 66 are defined which are filled with a magneto-rheological clutch liquid 28. The magneto- rheological clutch liquid 28 can not disappear because the clutch liquid gaps 66 are hermet-ically closed.

[0025] A permanent magnet element 32 is positioned

radially inside and in the center of the clutch disks 62, 64. The permanent magnet element 32 can be provided as a cylindrical magnet body 30 being provided axially shiftable within a cylindrical magnet chamber 22. The magnet chamber 22 is provided and defined by cylindrical chamber walls 25, 27 defining a engagement section 24 intersecting with the radial planes of the clutch disks 62, 64 and the clutch liquid gaps 66 and a disengagement section 26 not intersecting with the radial planes of the clutch disks 62, 64 and the clutch liquid gaps 66. The magnet chamber wall 25 of the engagement section 24 is made out of a non-ferromagnetic material, such as for example aluminium or plastic. The magnet chamber wall 27 of the disengagement section 26 is made out of a ferromagnetic material to shield the magnetic field of the permanent magnet element 30 with respect to the clutch liquid gaps 66 in the disengaged position of the perma-nent magnet element 32, as shown in figure 2.

[0026] In engaged position, the permanent magnet

el-ement 32 is close to the radial clutch liquid gaps contain-ing the magneto-rheological clutch liquid 28 therein so that the magnetic field generated by the permanent mag-net element 32 pemag-netrates the magmag-neto-rheological clutch liquid 28 inside the clutch liquid gaps 66 with a maximum magnetic flux.

[0027] The axially shiftable permanent magnet

ele-ment 32 is pretensioned by a pretension eleele-ment 44 into its engaged position, as shown in figure 1. This arrange-ment makes the clutch 16 failsafe because the perma-nent magnet element 32 is always pushed into its en-gaged position if the pneumatic actuator 42 should fail.

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by activation of the pneumatic actuator 42, the shiftable permanent magnet element 32 is pulled into and hold in its disengaged position, as shown in figure 2. In the dis-engaged position of the permanent magnet element 32 the magnetic field is remote and shielded with respect to the clutch liquid gaps 66 so that the magnetic flux in the clutch liquid gaps 66 is relatively low with the result that the viscosity of the magneto-rheological clutch liquid is relatively low. The clutch is disengaged.

[0029] As soon as the clutch 16 is switched into the

engaged state by deactivating the actuator 42, the shift-able magnet element 32 is pushed into its engaged po-sition by the pretension element 44, as shown in figure 1. In this state the magnetic field flux penetrating the clutch liquid gap 66 is relatively high so that the viscosity of the magneto-rheological clutch liquid is relatively high. In this engaged state, the output shaft 21 rotates with the same rotational speed as the input shaft 20. The output shaft 21 drives the pump rotor 19 of the pumping unit 18 so that the pumping unit 18 is pumping the fluid.

Claims

1. Mechanical combustion-engine-driven fluid pump

(10) comprising an input shaft (20) which is directly driven by the combustion engine (12),

a pumping unit (18) with a pump rotor (19), and a magneto-rheological multi-disk clutch (16) be-tween the input shaft (20) and the pump rotor (19), the clutch (16) comprising at least two radial input clutch disks (62) and at least two radial output clutch disks (64), the clutch discs (62, 64) defining at least two radial clutch liquid gaps (66) between them filled with a magneto-rheotogicat clutch liquid (28), a shiftable permanent magnet element (32) being shiftable between an engaged position wherein the permanent magnet element’s magnetic field pene-trates the clutch liquid gaps (26) with relatively high magnetic flux, and a disengaged position wherein the magnet element’s magnetic field penetration flux in the clutch liquid gaps (26) is less than in the en-gaged position, and

an actuator (42) for moving the permanent magnet element (32) between its engaged and its disen-gaged position,

whereby the permanent magnet element (32) is pro-vided shiftable in axial direction, characterised in

that a magnet chamber (22) is provided radially

in-wardly of the clutch disks (62, 64), the permanent magnet element (32) being provided in the magnet chamber (22) movable between the engaged and disengaged position.

(10) of claim 1, whereby the permanent magnet el-ement (32) is pretensioned by a passive pretension element (44) into the engaged position.

(10) of one of the preceding claims, whereby the ra-dial planes of the clutch liquid gaps (66) intersect with the permanent magnet element (32) in the en-gaged position.

(10) of one of the preceding claims, whereby a lon-gitudinal engagement section (24) of the magnet chamber wall (25) intersecting with the planes of the clutch liquid gaps (66) is made out of a non-ferro-magnetic material.

(10) of one of the preceding claims, whereby a lon-gitudinal disengagement section (26) of the magnet chamber wall (27) is made of a ferromagnetic mate-rial to shield the magnetic field of the permanent magnet element (32) with respect to the clutch liquid gaps (66) in the disengaged position of the perma-nent magnet element (32).

(10) of one of the preceding claims, whereby the ac-tuator is a vacuum acac-tuator (42).

Patentansprüche

1. Verbrennungsmotorgetriebene mechanische

Fluid-pumpe (10) mit einer Eingangswelle (20), die unmit-telbar von den Verbrennungsmotor (12) angetrieben ist,

einer Pumpeinheit (18) mit einem Pumpenrotor (19), und

einer magnetorheologischen Mehrscheibenkupp-lung (16) zwischen der Eingangswelle (20) und dem Pumpenrotor (19), wobei die Kupplung (16) mindes-tens zwei radiale Eingangskupplungsscheiben (62) und mindestens zwei radiale Ausgangskupplungs-scheiben (64) aufweist, wobei die Kupplungsschei-ben (62, 64) zwischen einander mindestens zwei ra-diale Kupplungsflüssigkeitsspalte (66) bilden, wel-che mit einer magnetorheologiswel-chen Kupplungsflüs-sigkeit (28) gefüllt sind,

einem verschiebbaren Permanentmagnetelement (32), das zwischen einer Eingriffsposition, in welcher das Magnetfeld des Permanentmagnetelements die Kupplungsflüssigkeitsspalte (26) mit relativ hohem Magnetfluss durchdringt, und einer Löseposition, in welcher Durchdringungsfluss des Magnetfelds des Magnetelements in den Kupplungsflüssigkeitsspal-ten (26) geringer als in der Eingriffsposition ist, ver-schiebbar ist, und

einem Aktuator (42) zum Bewegen des Permanent-magnetelements (32) zwischen seiner Eingriffs- und seiner Löseposition,

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Richtung verschiebbar vorgesehen ist,

dadurch gekennzeichnet, dass

eine Magnetkammer (22) radial einwärts der Kupp-lungsscheiben (62, 64) vorgesehen ist, wobei das Permanentmagnetelement (32) in der Magnetkam-mer (22) zwischen der Eingriffs- und der Löseposi-tion bewegbar angeordnet ist.

Fluid-pumpe (10) nach Anspruch 1, bei welcher das Per-manentmagnetelement (32) durch ein passives Vor-spannelement (44) in die Eingriffsposition vorge-spannt ist.

Fluid-pumpe (10) nach einem der vorhergehenden An-sprüche, bei welcher die radialen Ebenen der Kupp-lungsflüssigkeitsspalte (66) sich mit dem Perma-nentmagnetelement (32) in der Eingriffsposition schneidet.

Fluid-pumpe (10) nach einem der vorhergehenden An-sprüche, bei weicher ein langgestreckter Eingreifab-schnitt (24) der Magnetkammerwand (25), welcher sich mit den Ebenen der Kupplungsflüssigkeitsspal-te (66) schneidet, aus einem nichtferromagneti-schen Material besteht.

Fluid-pumpe (10) nach einem der vorhergehenden An-sprüche, bei welcher ein langgestreckter Löseab-schnitt (26) der Magnetkammerwand (27) aus ferro-magnetischem Material besteht, um das Magnetfeld des Permanentmagnetelements (32) in Bezug auf die Kupplungsflüssigkeitsspalte (66) in der Lösepo-sition des Permanentmagnetelements (32) abzu-schirmen.

Fluid-pumpe (10) nach einem der vorhergehenden An-sprüche, bei welcher der Aktuator ein Vakuum-Ak-tuator (42) ist.

Revendications

1. Pompe à fluide (10) mécanique entrainée par moteur

à combustion comprenant un arbre d’entrée (20) en-traîné directement par le moteur à combustion (12), une unité de pompage (18) avec un rotor de pompe (19), et

un embrayage (16) multidisque magnétorhélogique entre l’arbre d’entrée (20) et le rotor de pompe (19), ledit embrayage (16) comportant au moins deux dis-ques d’embrayage d’entrée radiaux (62) et au moins deux disques d’embrayage de sortie radiaux (64), les disques d’embrayage (62, 64) définissant entre

eux au moins deux fentes à liquide d’embrayage (66) radiales remplies d’un liquide d’embrayage magné-torhélogique (28),

un élément à aimant permanent (32) déplaçable étant apte à être déplacée entre une position d’en-gagement, dans laquelle le champ magnétique dudit élément à aimant permanent pénètre les fentes à liquide d’embrayage (26) avec un flux magnétique relativement élevé, et une position de dégagement, dans laquelle le flux de pénétration du champ ma-gnétique dudit élément à aimant dans les fentes à liquide d’embrayage (26) est inférieur à celui dans la position d’engagement, et

un actionneur (42) pour déplacer ledit élément à aimant permanent (32) entre sa position d’engage-ment et sa position de dégaged’engage-ment,

ledit élément à aimant permanent (32) étant dépla-çable dans la direction axiale,

caractérisée en ce qu’une chambre d’aimant (22)

est prévue radialement à l’intérieur des disques d’embrayage (62, 64), ledit élément à aimant per-manent (32) étant prévu dans la chambre d’aimant (22) de manière à être déplaçable entre la position d’engagement et la position de dégagement.

2. Pompe à fluide (10) mécanique entraînée par moteur

à combustion selon la revendication 1, dans laquelle ledit élément à aimant permanent (32) est précon-traint dans la position d’engagement par un élément de précontrainte (40) passif.

3. Pompe à fluide (10) mécanique entraînée par moteur

à combustion selon l’une quelconque des revendi-cations précédentes, dans laquelle les plans radiaux des fentes à liquide d’embrayage (66) se croisent avec ledit élément à aimant permanent (32) dans la position d’engagement.

à combustion selon l’une quelconque des revendi-cations précédentes, dans laquelle une section d’en-gagement (24) longitudinale de la paroi (25) de la chambre d’aimant se croisant avec les plans des fen-tes à liquide d’embrayage (66) est fabriquée d’un matériau non ferromagnétique.

à combustion selon l’une quelconque des revendi-cations précédentes, dans laquelle une section de dégagement (26) longitudinale de la paroi (27) de la chambre d’aimant est fabriquée d’un matériau fer-romagnétique pour protéger le champ magnétique dudit élément à aimant permanent (32) par rapport aux fentes à liquide d’embrayage (66) dans la posi-tion de dégagement dudit élément à aimant perma-nent (32).

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à combustion selon l’une quelconque des revendi-cations précédentes, dans laquelle l’actionneur est un actionneur à vide (42).

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REFERENCES CITED IN THE DESCRIPTION

This list of references cited by the applicant is for the reader’s convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description • US 7422093 B2 [0003]

• DE 102007020867 A1 [0005]