Mechanical combustion-engine-driven fluid pump [US9976606B2]

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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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888

496 B1

TEPZZ 888496B_T

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EP 2 888 496 B1

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EUROPEAN PATENT SPECIFICATION

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

22.06.2016 Bulletin 2016/25

(21) Application number: 12750761.4 (22) Date of filing: 23.08.2012

(51) Int Cl.:

F16D 37/02(2006.01)

(86) International application number:

PCT/EP2012/066464

(87) International publication number:

WO 2014/029445 (27.02.2014 Gazette 2014/09)

(54) MECHANICAL COMBUSTION-ENGINE-DRIVEN FLUID PUMP

MECHANISCHE VERBRENNUNGSMOTORBETRIEBENE 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) • BUCCHI, Francesco

I-56023 Pisa (IT)

• FRENDO, Francesco

I-55049 Viareggio - Lucca (IT) • FORTE, Paola

I-56123 Pisa (IT)

• FRANCESCHINI, Alessandro I-55012 Capannori (IT) • RIZZO, Rocco

I-56123 Pisa (IT) • MUSOLINO, Antonio

I-56100 Pisa (IT)

(74) Representative: Patentanwälte ter Smitten

Eberlein Rütten Partnerschaftsgesellschaft Burgunderstraße 29 40549 Düsseldorf (DE) (56) References cited: EP-A1- 1 225 361 JP-A- 61 248 924 US-A1- 2009 266 666 US-B2- 7 422 093

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

[0001] The invention refers to a mechanical

combus-tion-engine-driven fluid pump which is driven by an inter-nal combustion engine and is providing a liquid, pressu-rized gas or vacuum to an automotive unit.

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

cool-ant pump, a vacuum pump or a pump providing pressu-rized gas, for example pressupressu-rized air. The mechanical fluid pump is not to driven by an electrical rotor but is directly coupled to the combustion engine. As a conse-quence, the rotational speed of the fluid pump is propor-tional to the rotapropor-tional 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] EP 1225361 A1 discloses a mechanical

com-bustion engine-driven fluid pump comprising a magneto-rheological clutch which is energized by an electromag-net.

[0005] 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 brake assistance system.

[0006] It is an object of the invention to provide a

fail-safe mechanical combustion-engine-driven fluid pump with a magneto-rheological clutch. This object is solved with a mechanical combustion-engine-driven fluid pump with the features of claim 1.

[0007] 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" here has the meaning 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 direct coupling with the camshaft or the crankshaft of the engine.

[0008] The clutch is a combination of a

magneto-rhe-ological clutch and an eddy-current clutch whereby both clutch arrangements are engaged and disengaged by one single movable permanent magnet element. The clutch is provided between the input shaft and the pump rotor and comprises a clutch liquid gap between two clutch bodies. One clutch body is directly connected to the input shaft and the other clutch body is directly con-nected to the pump rotor. The clutch liquid gap between the two clutch bodies is 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.

[0009] 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 per-manent magnet element which is shiftable between a disengaged position in which the permanent magnet el-ement’s magnetic field penetration flux in the clutch liquid gap is low and an engaged position in which the magnetic field flux penetration in the clutch liquid gap is high. In its engaged position, the permanent magnet is close to the clutch liquid gap, and in the disengaged position, the per-manent magnet is more distant from the clutch liquid gap. The permanent magnet element is co-rotating with the input clutch body so that the permanent magnet element is always rotating with the rotational speed of the input shaft.

[0010] An electroconductive element is provided which

is co-rotating with the output clutch body. In the engaged position, the permanent magnet element is close to the electroconductive element, whereas in the disengaged position the permanent magnet element is remote from the electroconductive element. In the engaged position of the permanent magnet element, a relevant eddy-cur-rent effect is generated so that the electroconductive el-ement and the enclosed output clutch body are driven by the input side as long as there is a relevant rotational speed difference between the permanent magnet ele-ment and the electroconductive eleele-ment. In the disen-gaged position of the permanent magnet element, no rel-evant eddy-current effect between the permanent mag-net element and the electroconductive element is present.

[0011] The magnet element is moved between the

en-gaged and the disenen-gaged position by a separate magnet element actuator.

[0012] Since the magnetic field for penetrating the

clutch liquid gap 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 fails. In addition, also the eddy-current clutch arrangement is not depend-ent on the activation of an electromagnetic means.

[0013] Even if the mechanical-rheological clutch liquid

should be disappeared from the clutch liquid gap, a sub-stantive engagement via the eddy-current clutch ar-rangement is still present so that a substantive pumping performance is guaranteed. As a consequence, the fluid pump is highly failsafe, and is suitable for vital automotive pumps, such as a lubricant pump, a coolant pump or a vacuum pump for a brake assistance system.

[0014] 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.

[0015] Preferably, the permanent magnet element is

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per-5 10 15 20 25 30 35 40 45 50 55 manent magnet element is magnetized in circumferential direction, but can generally be magnetized in other di-rections, as in diametral, radial or axial direction.

[0016] 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.

[0017] According to a preferred embodiment, a

sepa-rate shift body is provided which comprises the perma-nent magnet element and which is provided with an axial guiding means interacting with an axial guiding means of the input clutch body. The shift body itself is guided axially and holds the separate permanent magnet ment. As a consequence, the permanent magnet ele-ment can have a simple ring-like form, whereas the shift body which is not permanently magnetized can have a relatively complex form and structure. The shift body and the permanent magnet element can be provided as gen-erally rotation-symmetric parts.

[0018] Preferably, the electroconductive element is a

part of the output clutch body. The electroconductive el-ement can be, for example, a disk-like or and/or a cylin-drical part of the output clutch body.

[0019] According to a preferred embodiment of the

in-vention, the clutch bodies are cup-shaped and form a cup-shaped clutch liquid gap between them. The clutch bodies are provided with a disk-like and with a cylindrical section. The permanent magnet is in its engaged position positioned inside the ring-like shaped cavity defined by the cup-shaped clutch liquid gap. Since the clutch liquid gap between the two clutch bodies is not only disk-shaped but also comprises a cylindrical portion, the total gap surface area is significantly increased and is provid-ed with a long lever arm of force to transmit high torque values without increasing the total diameter of the clutch.

[0020] According to another alternative embodiment,

the clutch is provided as a multi-disc clutch which is pro-vided with at least two radial input disks and at least two radial output disks, whereby the disks define radial clutch liquid gaps between them. The multi-disk configuration of the clutch allows a very compact diameter of the clutch.

[0021] Preferably, the radial input disks are

ferromag-netic and the radial output disks are provided as electro-conductive elements. According to another preferred em-bodiment, the radial output disks are provided with nu-merous openings, for example with radial slits, to realize a strong eddy-current effect.

[0022] 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 or could have an effect on the electroconductive element.

[0023] Alternatively, the actuator is an electromagnetic

actuator in form of an electromagnetic coil. If the electro-magnetic actuator is activated, the shiftable permanent magnet element is pulled or pushed into its disengaged position, i.e. distant from the clutch liquid gap.

[0024] Two embodiments of the invention are

de-scribed by referring to the enclosed drawings, wherein figure 1 shows a mechanical combustion-engine-driven fluid pump with a first embodiment of a clutch with cup-like clutch bodies in longitudinal cross-sec-tion in the engaged state,

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

figure 3 shows a second embodiment of a clutch re-alized as a multi-disc clutch in a longitudinal cross-section in the engaged state, and

figure 4 the radial cross section of radial output disc of the clutch of figure 3.

[0025] The figures 1 and 2 show a typical automotive

arrangement consisting of an internal combustion engine 12, a mechanical fluid pump 10 directly driven by the combustion engine 12 and a vacuum-driven brake as-sistance unit 14. The fluid pump 10 is designed as a vac-uum pump and provides low pressure to the pneumatic brake assistance unit 14. The combustion engine 12 is mechanically directly connected to an input shaft 20 of a clutch 16 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.

[0026] The clutch 16 is arranged between the input

shaft 20 and an output shaft 21 and is both a magneto-rheological and an eddy-current 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.

[0027] The output shaft 21 of the clutch is directly

cou-pled to a vacuum pumping unit 18 with a pump rotor 19. The clutch 16 is provided with two clutch bodies 22,24 defining a clutch liquid gap 26 therebetween filled with a magneto-rheological clutch liquid 28, an axially shiftable permanent magnet element 30 held by a separate shift body 54, a pretension element 44 designed as a spring and a pneumatic actuator 42. The clutch bodies 22,24 are both shaped so that they define a small shaped clutch liquid gap 26 between them which is cup-shaped and has a disk-ring portion and a cylindrical por-tion.

[0028] The permanent magnet element 30 is provided

as a circular permanent magnet ring body 32 which is seated in and fixed to the ferromagnetic shift body 54. The shift body 54 and the permanent magnet ring body 32 define a shifting unit 52. The input clutch body 24 is

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5 10 15 20 25 30 35 40 45 50 55 provided with a closed pneumatic chamber 57 wherein two or more axial guiding bolts 58 are provided. The shift body 54 is provided with two or more corresponding axial guiding bores 56 so that the guiding bolts 58 and the guiding bores 56 define an axial guiding means for the shift body 54. The shifting unit 52 therefore is arranged axially shiftable, and co-rotates with the input-shaft-sided clutch body 24.

[0029] The output clutch body 22 is provided with a

cup-like electroconductive element 50 with a ringlike por-tion and a cylindrical porpor-tion. The ringlike porpor-tion is pro-vided with radial openings and the cylindrical portion is provided with axial openings to provide a suitable struc-ture for an eddy-current clutch arrangement defined by the electroconductive element 50 and the permanent magnet ring body 32.

[0030] The shifting unit 52 is positioned inside of the

cup-shaped cavity 27 defined by the cup-shaped clutch liquid gap 26 in the engaged position of the permanent magnet element 30 which is shown in figure 1. In this engaged position, the permanent magnet body 32 is close to both portions of the clutch liquid gap 26 contain-ing the magneto-rheological clutch liquid 28 therein so that the magnetic field generated by the permanent mag-net element 30 pemag-netrates the magmag-neto-rheological clutch liquid 28 inside the clutch liquid gap 26 with a max-imum magnetic flux. Additionally, the engaged perma-nent magnet element 30 is close to the electroconductive element 50 so that they both define an engaged eddy-current clutch. As long as the rotational speed of the input clutch body 24 and the output clutch body 22 is different to each other, the output clutch body 22 is driven by the input clutch body 24 by eddy-current-caused forces.

[0031] The axially shiftable permanent magnet

ele-ment 30 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 30 is always pushed into its en-gaged position if the pneumatic actuator 42 should fail.

[0032] When the pneumatic actuator 42 is activated,

the pneumatic chamber 57 of the input clutch body 22 is evacuated by the pneumatic actuator 52 so that the shift-ing unit 52 is pulled into its disengaged position, as shown in figure 2.

[0033] The pneumatic actuator 42 is controlled by a

control unit 40 which is also connected to a pressure sensor 15 of the brake assistance unit 14 via a signal line. The control unit 40 engages and disengages the clutch 16 dependent on the pneumatic pressure in the working chamber of the pneumatic brake assistance unit 14. As long as the pneumatic pressure in the working chamber of the brake assistance unit 14 is below a critical pressure value, the clutch 16 remains disengaged by ac-tivation of the pneumatic actuator 42 so that the shiftable magnet element 30 is pulled into and hold in its disen-gaged position, as shown in figure 2. In the disendisen-gaged position of the permanent magnet element 30 the mag-netic field penetrating flux of the clutch liquid gap 26 is

relatively low so that the viscosity of the magneto-rheo-logical clutch liquid is relatively low. Additionally, the per-manent magnet body 32 is remote from the electrocon-ductive element 50 so that no eddy-current effect is present. As a consequence, the clutch slip is high so that the clutch is more or less disengaged.

[0034] As soon as the pneumatic pressure in the

work-ing chamber of the brake assistance unit 14 exceeds above a critical pressure value, the clutch 16 is switched into the engaged state by not activating the actuator 42 so that the sfliftable magnet element 30 is pushed into its engaged position by the pretension element 44, as shown in figure 1. In this state the magnetic field flux penetrating the clutch liquid gap 26 is relatively high so that the viscosity of the magneto-rheological clutch liquid is relatively high. Additionally, a strong torque is trans-mitted from the input clutch body 24 to the output clutch body 22 caused by the eddy-current effect. As a conse-quence, the clutch slip is low so that the clutch is more or less engaged. 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 working chamber of the brake assistance unit 14 is evacuated until the pneumatic pressure in the working chamber falls below the critical pressure value.

[0035] Figures 3 and 4 show a second embodiment of

a clutch arrangement which is provided as a multi-disc clutch 60. The disc-clutch 60 is provided with four radial input disks 62 of ferromagnetic material and five radial output disks 64 of highly electroconductive material, for example copper.

[0036] The input disks 62 are provided axially between

the output disks 64. At the outer circumference of the output disks 64 connection rings 68 made out of a non-ferromagnetic material are provided. The permanent magnet element 30’ is realized as a ring magnet which can be magnetized axially or circumferentially so that four magnet sectors are present as shown in figure 4. The output disks 64 define the electroconductive elements 70 and are provided with eight sector-like openings 72 so that the electroconductive elements 70 are formed as a spoke wheels. Between the discs 62, 64 radial ring-like clutch liquid gaps 66 are defined wherein the magneto-rheological clutch liquid is present.

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 clutch (16) between the input shaft (20) and the pump rotor (19), the clutch (16) comprising an input clutch body (24) and an output clutch body (22) and transferring the rotation of the input clutch body (24) to the output clutch body (22) in the engaged clutch

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5 10 15 20 25 30 35 40 45 50 55 state,

whereby the clutch (16) is a combined magneto-rhe-ological and eddy-current clutch (16), the clutch (16) comprising

a closed clutch liquid gap (26) between the two clutch bodies (22, 24), the clutch liquid gap (26) being filled with a magneto-rheological clutch liquid (28),

an electroconductive element (50) co-rotating with the output clutch body (22),

a shiftable permanent magnet element (30) be-ing provided co-rotatbe-ing with the input clutch body (24) and being shiftable between

an engaged position wherein the perma-nent magnet element’s magnetic field pen-etrates the clutch liquid gap (26) with high magnetic flux and the permanent magnet element (30) is close to the electroconduc-tive element (50), and

a disengaged position wherein the perma-nent magnet element’s magnetic field pen-etration flux in the clutch liquid gap (26) is less than in the engaged position and the permanent magnet element (30) is remote from the electroconductive element (50), and

an actuator (42) for moving the permanent magnet element (30) between its engaged and its disen-gaged position.

(10) of claim 1, whereby the permanent magnet el-ement (30) is provided shiftable in axial direction.

(10) of one of the preceding claims, whereby the per-manent magnet element (30) is provided with a a shift body (54) which comprises a permanent magnet body (32) and which is provided with an axial guiding means (56) interacting with an axial guiding means (58) of the input clutch body (24).

(10) of one of the preceding claims, whereby the electroconductive element (50) is a part of the output clutch body (22)

(10) of one of the preceding claims, whereby the clutch bodies (22,24) are cup-shaped and form a cup-shaped gap (26) between them, and the perma-nent magnet element (30) in its engaged position is positioned inside of the cup-shaped cavity (27) de-fined by the cup-shaped gap (26).

(10) of one of the preceding claims, whereby the clutch (60) is provided as a multi-disc clutch (60) which is provided with at least two radial input disks (62) and at least two radial output disks (64), the discs (62, 64) defining radial clutch liquid gaps (66) between them.

(10) of claim 6, whereby the radial input disks (62) are ferromagnetic and the radial output disks (64) are provided as electroconductive elements (70).

(10) of one of the claims 6 or 7, whereby the radial output disks (64) are provided with openings (72).

(10) of one of the preceding claims, whereby the per-manent magnet element (30) is pretensioned by a passive pretension element (44) into the engaged position.

(10) of one of the preceding claims, whereby the ac-tuator is an electromagnetic acac-tuator.

(10) of one of claims 1-4, whereby the actuator is a vacuum actuator (42).

Patentansprüche

1. Mechanische verbrennungsmotorbetriebene

Flüs-sigkeitspumpe (10) mit einer Antriebswelle (20), die unmittelbar von dem Verbrennungsmotor (12) ange-trieben ist,

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

einer Kupplung (16) zwischen der Antriebswelle (20) und dem Pumpenrotor (19), wobei die Kupplung (16) einen Eingangskupplungskörper (24) und einen Ausgangskupplungskörper (22) aufweist und die Drehung des Eingangskupplungskörpers (24) im Kupplungseingriffszustand an den Ausgangskupp-lungskörper (22) überträgt,

wobei die Kupplung (16) eine kombinierte magne-torheologische und Wirbelstromkupplung (16) ist, wobei die Kupplung (16) aufweist:

einen geschlossenen Kupplungsflüssigkeits-spalt (26) zwischen den beiden Kupplungskör-pern (22, 24), wobei der Kupplungsflüssigkeits-spalt (26) mit einer magnetorheologischen Kupplungsflüssigkeit (28) gefüllt ist,

ein elektrisch leitfähiges Element (50), das mit dem Ausgangskupplungskörper (22) dreht,

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5 10 15 20 25 30 35 40 45 50 55 ein verschiebbares Permanentmagnetelement (30), das mit dem Eingangskupplungskörper (24) drehend vorgesehen ist, und zwischen

einer Eingriffsposition, in welcher das Ma-gnetfeld des Permanentmagnetelements den Kupplungsflüssigkeitsspalt (26) mit starkem Magnetfluss durchdringt und das Permanentmagnetelement (30) dem elek-trisch leitfähigen Element (50) nahe ist, und einer gelösten Position verschiebbar ist, in welcher der Magnetfeld-Eindringfluss des Permanentmagnetelements in den Kupp-lungsflüssigkeitsspalt (26) geringer als in der Eingriffsposition ist und das Permanent-magnetelement (30) von dem elektrisch leit-fähigen Element (50) entfernt ist, und einem Aktuator (42) zum Bewegen des Permanent-magnetelements (30) zwischen dessen Einrück- und Ausrückposition.

Fluid-pumpe (10) nach Anspruch 1, bei welcher das Per-manentmagnetelement (30) in axialer Richtung ver-schiebbar ist.

Fluid-pumpe (10) nach einem der vorhergehenden An-sprüche, bei welcher das Permanentmagnetele-ment (30) mit einem Schiebekörper (54) versehen ist, welcher einen Permanentmagnetkörper (32) auf-weist und welcher mit einer Axialführungseinrich-tung (56) versehen ist, die mit einer Axialführungs-einrichtung (58) des Eingangskupplungskörpers (24) zusammenwirkt.

Fluid-pumpe (10) nach einem der vorhergehenden An-sprüche, bei welcher das elektrisch leitfähige Ele-ment (50) ein Teil des Ausgangskupplungskörpers (22) ist.

Fluid-pumpe (10) nach einem der vorhergehenden An-sprüche, bei welcher die Kupplungskörper (22, 24) becherförmig sind und einen becherförmigen Spalt (26) zwischen einander bilden, und das Permanent-magnetelement (30) in seiner Eingriffsposition in dem durch den becherförmigen Spalt (26) gebilde-ten becherförmigen Hohlraum (27) angeordnet ist.

Fluid-pumpe (10) nach einem der vorhergehenden An-sprüche, bei welcher die Kupplung (60) als Mehr-scheibenkupplung (60) ausgebildet ist, die mit min-destens zwei radialen Eingangsscheiben (62) und mindestens zwei radialen Ausgangsscheiben (64)

versehen sind, wobei die Scheiben (62, 64) zwi-schen einander radiale Kupplungsflüssigkeitsspalte (66) bilden.

Fluid-pumpe (10) nach Anspruch 6, bei welcher die radi-alen Eingangskupplungen (62) ferromagnetisch sind und die radialen Ausgangskupplungen (64) als elektrisch leitfähige Elemente (70) ausgebildet sind.

Fluid-pumpe (10) nach einem der Ansprüche 6 oder 7, bei welcher die radialen Eingangsscheiben (64) mit Öff-nungen (72) versehen sind.

Fluid-pumpe (10) nach einem der vorhergehenden An-sprüche, bei welcher der Permanentmagnet (30) durch ein passives Vorspannelement (44) in die Ein-griffsposition vorgespannt ist.

Fluid-pumpe (10) nach einem der vorhergehenden An-sprüche, bei welcher der Aktuator ein elektromag-netischer Aktuator ist.

Fluid-pumpe (10) nach der Ansprüche 1 - 4, bei welcher der Aktuator ein Vakuumaktuator ist.

Revendications

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

à combustion interne, avec

un arbre d’entrée (20) directement entrainé par le moteur à combustion interne (12),

une unité de pompage (18) avec un rotor de pompe (19), et

un embrayage (16) entre ledit arbre d’entrée (20) et ledit rotor de pompe (19), ledit embrayage (16) com-prenant un corps d’embrayage d’entrée (24) et un corps d’embrayage de sortie (22) et, en état engagé de l’embrayage, transférant la rotation du corps d’embrayage d’entrée (24) au corps d’embrayage de sortie (22),

où l’embrayage (16) est un embrayage (16) combiné à effet magnéto-rhéologique et à courants de Fou-cault, ledit embrayage (16) comprenant

une fente à liquide d’embrayage (26) fermée en-tre les deux corps d’embrayage (22, 24), la fente à liquide d’embrayage (26) étant remplie d’un liquide d’embrayage (28) magnéto-rhéologique, un élément (50) électroconducteur en rotation simultanée avec le corps d’embrayage de sortie (22),

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5 10 15 20 25 30 35 40 45 50 55 en rotation simultanée avec ledit corps d’em-brayage d’entrée (24) et déplaçable entre une position engagée, dans laquelle les champs magnétique dudit élément d’aimant permanent pénètre la fente à liquide d’embrayage (26) avec un flux magnétique élevé et ledit élément d’aimant permanent (30) se trouve près dudit élément électroconducteur (50), et

une position dégagée, dans laquelle le flux de pénétration des champs magnétique dudit élé-ment d’aimant permanent dans ladite fente à li-quide d’embrayage (26) est inférieur à celui dans la position engagée et ledit élément d’aimant permanent (30) est loin dudit élément électroconducteur (50), et

un actionneur (42) pour déplacer ledit élément d’aimant permanent (30) entre la position engagée et la position dégagée.

à combustion interne selon la revendication 1, dans laquelle ledit élément d’aimant permanent (30) est déplaçable dans la direction axiale.

à combustion interne selon l’une quelconque des re-vendications précédentes, dans laquelle ledit élé-ment d’aimant permanent (30) est muni d’un corps de déplacement (54) comprenant un corps d’aimant permanent (32) et étant muni d’un moyen de guidage axial (56) coopérant avec un moyen de guidage axial (58) dudit corps d’embrayage d’entrée (24).

à combustion interne selon l’une quelconque des re-vendications précédentes, dans laquelle ledit élé-ment électroconducteur (50) fait partie dudit corps d’embrayage de sortie (22).

à combustion interne selon l’une quelconque des re-vendications précédentes, dans laquelle les corps d’embrayage (22, 24) sont en forme de coupes et forment entre eux une fente (26) en forme de coupes, et ledit élément d’aimant permanent (30) est posi-tionné, dans sa position engagée, dans la cavité en-forme de coupes (27) définie par la fente (26) en forme de coupes.

à combustion interne selon l’une quelconque des re-vendications précédentes, dans laquelle l’embraya-ge (60) est un embrayal’embraya-ge multi-disques (60) muni d’au moins deux disques d’entrée (62) radiaux et au moins deux disques de sortie (64) radiaux, les dis-ques définissant entre eux des fentes à liquide d’em-brayage (66) radiales.

à combustion interne selon la revendication 6, dans laquelle les disques d’entrée (62) radiaux sont fer-romagnétiques et les disques de sortie (64) radiaux sont prévus comme éléments électroconducteurs (70).

à combustion interne selon l’une des revendications 6 ou 7, dans laquelle les disques (64) sont formés avec des ouvertures (72).

à combustion interne selon l’une quelconque des re-vendications précédentes, dans laquelle ledit élé-ment d’aimant permanent (30) est précontraint vers la position engagée par un élément de précontrainte passif (44).

à combustion interne selon l’une quelconque des re-vendications précédentes, dans laquelle l’action-neur est un actionl’action-neur électromagnétique.

à combustion interne selon l’une quelconque des re-vendications 1 - 4, dans laquelle l’actionneur est un actionneur à vide (42).

(8)

(9)

(10)

(11)

REFERENCES CITED IN THE DESCRIPTION

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Patent documents cited in the description