GB2375374A

GB2375374A - Vacuum pump

Info

Publication number: GB2375374A
Application number: GB0216991A
Authority: GB
Inventors: Dieter Otto; Michael Biesek; Peter Giese
Original assignee: LuK Automobiltechnik GmbH and Co KG
Current assignee: Magna Powertrain Hueckeswagen GmbH
Priority date: 1999-12-23
Filing date: 2000-11-29
Publication date: 2002-11-13
Also published as: GB0216991D0; AU2504301A; WO2001048381A2; DE10084170D2; FR2802984B1; FR2802984A1; DE10059275A1; WO2001048381A3; ITMI20002820A1; IT1319734B1

Abstract

A vacuum pump comprising a rotor which may be driven and a method for production of the rotor are disclosed. At least one vane in a housing may be set in rotation by means of the rotor.

Description

2375374 1

- 1 cueJM PUMP The in rE nt on relates to a vacuum pump, especially for 5 brake force ar lifyiny deprives in rehicles, with a dri reable rotor through which at least c:ne vane is Bet in rotation in a housing, and to a process [ r manufac ur i ng a rotor for a pump, in particular a Rum pump.

lo Vacuum pumps of the type den;::ribed here me known. They are for example used for a:brake force amplifying device in a motor vehicle and hectare a rotor which is set in rotation with the assistance of a cLri re The rotor arranged in a housing is in engagement with at least one: 15 arena made of steel which upon rot atior of the rotor slides along on a contour riling The rotc:r::onsists of;ever2 1 i ndlvidual pares; which are releasably connected with one another. . 20 Such vacuum pumps are known. For example I)E 87 00 135 Ul discloses a pump with a rotor conaistiF of ceramic or concrete polymer, ME 23 48 441 Al discloses a pimp? with a Notch consisting of electro graphite and DIE C:MlB56184 as well as the D:D 1 S5 102 diE,closem pump with rotor 25 partially coated with a metal and/or a non metal.

It has become apparent that the rotor, because cf its weight, has a large mso:nt of inertia whereby the erfo nance requirernent of the vac:uun pump are 30 undesirably high. As a result of this the entire pump drive system iE; highly loaded. The rotor has furthermore m= siv=, large scale, cost inten=-' re construction aE; a.

- - result of which ache high rnanufacturingl costs of the rotor come about through the necessary machining processes anchor finishing processes.

S l:t is therefore an obj ect of the invention to produce a vacuum pow of the type set out above and a process for manufacture calf rotor which does rot here these disadvant ages.

10 To allure this fib; ect ' ve, a vacuum punk is proposed which has at least one drivable rotor through which at least one vane is set ire rotation in a housing, The vacuum pump is; c haracterised in that the rotor arldior the vane consists or consist of aluminium or I1 alurniniurn alley.

15 The rotor and the vane padre in con pari sort:Lo known rotors: a law weight. ThZls the performance requirement of the vacuum puTr p iE; only relatl- ly low as result of the small moment of inertia of the rotor and the vane guided In a slot ire the rotor which In the as;err led state Morons c a const:r ctional unit together with the rotor. It will be clear that the performance requirement of the vacuum pump can already be reduced if eitne:r only the rotor or only the vane in node of? aluminium nd o:r an alum:inium alloy.

5 P^ccordiIlg to a further development of the invention the rc:'tor andfor the vane are made in cone piece ThiE' enables simple and cost effective r ufacture. Furthermore, - through a one piece const:caction of the rotor and the vane a compact canstnlation is possible so that the package 30 space for the vacuum pump and in particular the package height cart be redlined.

According to a further development of the nvention the rotor in formed by chinless forming, i.e. in the manufacture any, or the treatment of the rotor no chip 5 removal takes place as is the case for exE 'nple on milling, grinding or the like. The rotor which can be mar ufactuxedl for example by casting, forging, pressing, straightening Andover separating through part ing, can therefore be manufactured with minimal outlays. In the ch pless 10 forming, especially Erich an extrusion press, the rotor can be made to tight tolerances so that if nect":S ry a mechanical, ir: particular a material rernO,ring subsequent treatment can lee avoided. Obviously it is also possible that the rotor can be subsequently worked on after its 5 formation, for example transverse boring or the like can be made where necessary.

In a preferred e nbodime:it the rotor is made by extrusion.

iJsing cold extrusion hoe the advantage that the rotor can 2 0 be extruded in uFle operationa1 step. Hot extrusion has the adamant age that the f inished rotor in at learnt substantially pore free and is also useable with alun niuTn with a high silicon content.

25 In an advz ntageoue embodiment of the vacuum pump it is prided that at least a part of the housing is manufactured from aluminium or an aluminium alloy.

There}: y the weight of the vacuum pump can be further reduced. The housing c: onsists of at least one housing 30 part and a cover closing the housing part r and both the

- 4 - housing part and also the comer a. be m.=nuf ctu =d froTr al' Tr. irlium or an aluTniniurn al oy.

An embodiment of the racuum putt is preferred that is 5 characterized in that the rotor andior the vane has at least one alacrity open to the outside. Through the i.rtroduction of charity in the rotor end for the vane, thin walls can be achiexrecl without arty further measure; The weight can thus be lightened relate Ore to a known rotor 10 consisting of metal, while further reductions can be made using alu nirlium and/or an aluminium alloy rotor. The form and E;ize of the cavity -can he chosen practically at will.

It is especially important that::he walls of the rotor which remain are; uffi::ierltly thick so that failure Is 15 excluded.

In a urthe: embodiment or the racuu'T pump the rotor undJor the Deane have at least one continuous wall extending transverse or substantiallytransverse to its; 20 longitudinal centre line:. Thus in rotor having several cavities it can be ensured that no air tra rel from the drive aide through the rotor into the vacuum purm. As result of the conti=uOuB wall also no additional seals are rebut real. With the Oracle the contimlou wall prevents a 25 short circuit,:i. e. a medium passage}>e tween a resE:u -e and suet ion region or the vacuum pump In preferred err odiTnents the rotor andior the vane are anodi zed. Thus wear cuff the rotor andfor the vane can LEE 3 0 avow deaf.: urtherroore, Or- Inch hous ng of E l mi ium aid an aluminium al' oy which received the rotor and,for an

aL 'm,inium cover which clones the putting space containing the rotor cars be j oined to the enf ace of the rotor to aneroid a cold welding. If the housing uf the vacuum pump anchor the coNrer clc: sing the pump chaser in or plastics 5 anodizing of the rotor and of the vane is not necessarry.

The preferred norl-anodised housing, which is softer than the anodized rotor and ache Cane. hat; good rur r ing properties lo cac rdis g to a further de relopment of the in rention, the -rotor especially from a combustion engine of motor vehicle, in particular a motor rehic:1 e, a water vehicle or rail vehicle is sul: j ected to a torte through clutch, in particular from a a nshaft of the combustion engine :Ls As a result of the low moment: of inertia of rhe rotor, the camshaft does not need to be hardened GO that the costs for the pump andfor for, its dry ve can 1: e reduced.

Purthe:c preferred is an eTnbadiment of the vacuum pump i n 2u which the clutch has a slot in which a drive element engages. Acco;rdiny to other eTr odiments of the i:lYentiOn the clutch has a drive spigot which engages in corresponding slot in the drive element On both cases a simple connection between the vacuum pump aTld the drive 25 can}:'e realized, To solve the adjectives furthermore process for manufacturing rotor for a pump in particular vacuum pump, is proposed which is characteriseci in that the rotor 30 and/ar the vane of alumin:ium or an aluminium alloy is Trm ura tured by chipless forming. The rotor and the vane

- which haste only relay inanely small weight can be prepared for example by original fining, such as for example canting andfor by work- ng, such a for example forging, pressing, s rai rhtenlng and separating by cutting andfor 5 dividing or the like. Thus rc' ors and possibly also the Greene con be prow erably o r pleted or at least stantially completed. Should machining operation, such aa for example milling, boring or ache like be absolutely nec:e=Erary, then the outlay for thin is preferably small.

10 Thus rotor and the vane are pref erabl des -. fined so that they are ready for use after the forming process anal do riot have to}: e equ ntly machined.

- In a particularly preferred embodiment of the process the 15 rotor is manufactured by hot extrusion or cold extrusion.

- In, the extension the rotter is manufactured from a billet -: with th_ help of ram. arid a preens dye' preferably in a single press. In this way the:coto' billet in t};e cold andic r warned state is presser] out through a gap between 20 the rate. arid the press dye, so that its flow threE halc] 2 s exceeded. The rotor can}:e n anufactllred in a particularly cost ef fecti re manner.

In the Doll owing the invents on grill be described with the 25 aid of the clrawings, they show: Figure longitudinal section through an embodiment of a rotor for a pump; 30 Figure a front view of the c,tc r or its end face facing Et jitiV;

- 7 Figure 3 front view of the rotor on the side facing away from the dire; Figure 4 a langitudirlal section through the rotor according to Figure 2 illustrated on the section line B-; Figure 5 longitudinal sect ion through the rotor on the 10 section line A-A from Figure 2; Figure an enlarged illustration of the part of the rotor indicated by rein in Figux e 4 i Figure 7 a longitudinal section tI:ro gh the rotor on the i see: Lion line O-D front l?.gure G; Figure a side view of the rotor according to the For gures 1 to 8; Figures g and 10 are each a perspecti.ve illustrate on of the rotor and Figures 11 and 12 are each an embodiment of a vane to work 25 with the rotor, in perspective view.

The embodiments of the rotor 1 for a -vacuum pump described in the following have irk coTumon that the rotor 1 is formed in one piece and is of aluminium or an alumirlium alloy.

30 The rotor 1 is in an advantageous manner manufactured by Shipley forming, in particular by extrusion.

- - Figur 1 shows longitudinal section of the rotor 1 for a not illustrated vacunn: pump, which has a contir uouE; slot 3. The outer surface of the rotor 1 is cylind.ri ally fc rtned. The slot 3 trE rm rerse to the 14ngitudinal centreline 5, which is s;imultan ously: a1 o the rotational axis of the rotor 1, se:cv to receive a rig: illuf;: ated crane which slides in En diatnetric21 direction within the slot 3. The slot 3 is placed in thin embodimerlt in the 10 end face 7 cing away from the drive of the rotor 1, z nd is thus edge open. As drive for the rotor there can be f or example a not illustrated drive shaf a, f or example a camshaft of conit ustion engine: of a motor vehicle, which is supplied with torque. Obviously it is possible that 15 the rotor 1 could a' so be driven: by rne:;ne: of an electrorr tor, a pulley strive or the 1 Me, filet longitudinal section 11 of the' rotor 1, which is itself substantially cylindrical, s e as bearing 13 of go the here one sided, thus cantilevered rotor '. A elide bearing is envisaged as the preferred type of bearing.

Pu:liacent the bearing 13 there is; a second or gltudinal section 15 of greater diameter which, considered transverse to the longitudinal cer treline S in:interrupted 25 I:'y the slot 3 for the vane, as can be seer frown Figures and 3 which show a front view on the end face 7 and on the end face 17 facing awry from the drive of the rotor 1, respectively. 30 As car: be seer1 from Figures 1 and clarity 19 is included in the end face g of the rotor ', preferably

- 9 - according to the mOC9e Cat nanutaoture of the rotor - the end face of the rotor has cavity 19 which here is f owned}fly bl loll bore. The cavity 19 serve s to reduce the weight of the rebox and thus its moment of ines: tie 5 The blind bore concentric with the longitudinal centreline extends through the hole of the second longitudinal section 15 up..o the bearing 13. In Brother 1 not l'ustrated, err odimer t the rotor has severe' cavit:.ies.

- Independent of the number size and shape of the ca riti.es 10 tile wall" of the rotor are preferably very thin but Till Phi ck enough to preprint any Joe eak up of the rote: r.

Or: the end face L7 c:f the rotor facing the drive slot 3 is provided ire an end surface 21, or the end;urf ce 21 15 has the Blot 2 which serves so receivers preiCeral:ly crowned, not il.lu:3trated driers element. The bilge ei meTlt is introducer: O:r inserted into the slot 2 3 arid can be held in-the slot 23 so that the rotor in which the end face 17 adj acent the end region of the longitude na i secti r1 i! 20 in the region of the curved deformations 26 arid '7, which lie opposite one another, are Wheezed ad therefore permanently deformed. The drive element can be T:art of clutch and erred for transf erring a torque from the drive to the rotor 1.

Clearly the coupling between the rotor and the divide can be achieved in other ways. For example, in place of the slot 23, the rotor car also have drive spigot, f r exalryple a dihedron which is received ir1 a clot in the 30 dri re elerr.ent.

- 10 F=gures 4 - lD show [u-rther Curfews of the rotor described with the mid of figures 1 - 3. The sane parts are provided with the same reforenc:e numeral so that reference can be made. back to the description of the

5 prec:eding f inures.

As result of the shape and design of the rotor 1 this in Dapple of being manufactured in a simple and cost effective way by Shipley foxing, without requiring a 10 curse-ant process in which n ate -ial is reed The manufacture of the rotor 1}:y extrusion facilitates achievement of narrow tolerances without a nechanical reworking of the rotor being necessary for this, ... 15 Figure 11 macaws a per p t:Lve view of an eIT idlment of a one- piece Crane a>- Ode of aluminum or an alumir..um alloy which in insertable in clot 3 o the rotor i. The vane 2.

has rectangular cross ec:tion.. Ire each of t Al faces 31 and 33 a slot 35 transverse to the longi cudinal extent 20 of the vane 2s in provided, for xecei lng a,: not illustxatecl;ea1. The crane 9 contacts with the end faces :41, 33 and/or with seals ire e- slots 35 against the inner pert pheral surface of a conto:I- rills which bounds Et pump shaver. with the aid of the vane arid the seal short 2S circuit is prevented from a suction region and a pressure region of the pump chamber, r:n each of the end faces 3 and 33 of the vane recess 37 here rectangular in - cress section, is profiled which AD r;er res, inter hip, to reduce the weight of the vane 29 and thus its moment of inertia and to prc> ride thin wall

- l' thicknesses so that the- vane - in easily manufactured or first manufactured by extrusic>n, casting or the like. The recesses, 3 7 and 39 are separated from one another by wall 41. which rune; transverse to the longitudinal middle axis 5 of the vane 29. There a thus no passage for medinTn between the re::esses 7 and 9 Figure 12 chase further embodiment c, E the vane 2 which do ffers froZn the vary described with reference to Figure 10 11 especially ir: that it is simply wider and that; in each end face 31 and 33 two recesses 37, 37'' and 39,:39' are mounted in which each pair of opposing reck 3 7, 3 9 ox 37' and 39 are ep ated by. continuaue wall 41, wall 41 extends ng transverse to the ongitudinal axis of the 5; Crane.

: From: th@ above discussion the process acc:v ding to the : Invention can 1:e gathered. lt cor sists in that the rotor 1 andJor the vane are manufactured by Shipley forming, 20 for example by casting, injection moulcling, pressing, especially extrusion pressing and the like EM that they - can be manufactured in. 2 cost effective manner. The alt3minium rotor, in comparison Faith rotor of metal, has only a small weight and thus a reduced rent of inertia, 25 likewise the vane" The cavity 19 and the slit 23 in the rotor 1 serving to reduce weight as well as the recesses in the Crane are so designed that they can be manufactured without fu:cther steps also by chiseled forming.

30 The claims filed with the application are formulation proposals without prejudice to more extensive paten c

- 12 protection. The applicant reserves the right tc' claim features presently only deE;criLed in the description

anchor in the drawings.

5 C!ro -references weed in the: sub-claims refer to the further development of the eubj ect mattE>r of: the main claim by the features calf the sob- claims; they are not to he seen as an abandonment cot achievement c; independent separate protection for ache features of the croE's 10 referenced sub-claims. The subject nattier of these s -

clai rm forms however also ind apendierlt inventions.

i

Claims

-13 C1 aims 1. Vacuum pump, in particular for brake force amplification

devices in vehicles, with a drivable rotor 5 through which at least one vane is rotatable in a housing, characterized in that the rotor andfor th vane Co0 iBt of aluminium or an alum nium alloy.

2. Vacuum pump, particularly according to Claim 1,

10 ckaracterised in that the rotor, andior the vane are formed in one piece, 3. vacuum pump, particularly according to Claim or 2, characterized in that the rotor is manufactured by 35 chipless forming preferably by extrusion.

4. Vacuum pump, particularly according to one of the preceding claims. characterized in that at least cane part of the housing is manufactured from aluminium or an 20 aluminium alloy.

5. Vacuum pump especially according to one of the preceding claims, characterized in that the roach and,fc r the vane has at least cane ca ri cy opened at one edge.

6. r ccaum pump, particularly according tc> one of Ache preceding claims, charE'cterised in that the rotor andJor the e hare at 1eAst oT e continuous wall extending transversely to or s star:tially transversely to its 30 longitudinal middle axis.

- 14 7. vacuum pump, particularly according to one of the pre,, ding claims, characterisec3 in that the rotor andlor the vane have a seal 1 thi -kne. s.

s a. Vacuum pump, particularly according one of the preceding claims, characterized in that the rotor andlor the varle i s or are anod:L Bed.

s Vac-. um pump,,: -icularly according to orate of the IO preaching claims, characterized ir: that the rotor receives a torque through clutch, preferably,[rom -' on, -,tion engine of the vehicle.

lo. Vacuum pump! particularly a,cording to one of the :15 preceding claims charac Derided in thief; the clutch noes slot ir1 which a dot Are lent engages, or a drive spigot that engages in a corresponding slot in the drive element.

11. Process for n nufac uring a rotor for pumy, i 20 particular for a vacuum pump according to cone of the preceding Claims 1 to lo characterized in theft the rotor andior the vane niche of aluminium or an aluminium alloy is or are manufactured by chipleE;s fore ing.

25 l9. Process, particularly according to claim Il.

characterized in that the rotor anchor the crane is or ore manuf actured by extruE:ion.

13. Process, particuls rlSy ac:cordir g try one of the 30 preceding Claims;1 and 12, characterized in that the rc: For andior the vase are manuf actured in one pi ece.

- - 15 1. vacuum. pump, particularly far brake force amplifying devices in vehicles, with a drivable rotor by means of which at least one vane can De ret in rotation in a housing, characterized by the special design and manner of opera ci on i n accordance with the accompanying appllcatior clocumer:rts. 15. Process for manufaccllring fur a actor for pump, ire 0 particular for a racuum purrs according to one of the pre cecling Claims 1 to 10, characte:ei ed by the process steps anchor price procedures disco Oswald in the application documents.

À - 15

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