AU623101B2

AU623101B2 - Electric motor

Info

Publication number: AU623101B2
Application number: AU25331/88A
Authority: AU
Inventors: Albert Blum; Gunter Kramer
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-10-26
Filing date: 1988-10-13
Publication date: 1992-05-07
Anticipated expiration: 2008-10-13
Also published as: AU2533188A

Description

PCDP I DATE 23/05/89 APPLN. ID 25331 88 IOJP D AT 29/06/89 PCT NUMBER PCT/DE88/00631 INTERNATIONALE ANf i Veroffentlichungsdatum: 5. Mai 1989 (05.05.89) (21) Interniationales Aktenzeichen:. PCT/DE88/00631 (81) Bestimmungsstaaten: AU, BR, JP, KR, US.

(22) Internationales Anmeldedatumn: 13. Oktober 1988 (13,10,88) Verifffentlicht Alit internaiona/eln Recherchenberich.

(3t) Prioritatsaktenzeichen: P 37 36 159,7 (32) Prioritatsdatum: 26, Oktober 1987 (26.10.87) (33) PrioritAtsland: DE (71)(72) Anmcelder und Erfinder: BLUM, Albert (DE/DE]; D-5204 Lohmar I (DE).

(72) Erfinder; und Erfinder/Anmelder fnwr Air LIS). KRAMNER, G(inter (DE/DE]: Lothar- Irle-Stra3e 18, D-5900 Siegen I (D E), (74) Arnwiilt,- L.IPPERT, H-ans-Joachirn Frankeniforster Strage 135-137, D-5060 lBergisch Glaclbach I

(DE),

(54)TItle- ELECTRIC MIOTOR (54) Bezelchnung, E LEKTRONIOTO R (57) Abstract *An electric motor comprises a sealed housing consisting. of 4 stainless steel sheet ease a stator a shaft which projects from the housing, and two centering 1 pieces 7) disposed on either side of the stator (21 which rest against the front faces of the stator and in which the shaft is supported. The housing of this motor can il withstand increased mechanical stresses while retaining till the known advantages, and In addition can be manufactured at low cost, For th is p urpose, the centering pieces 7) are preferably thick-walled castings whose outer diameter on the side racing the stator is greater than that of the stator, on which they engage by interlocking. The end sections (3 1, 32) of the centering pieces 7) facing aw~ay from the stator have at least one constriction and thle sheet case (28) is in close contact with the bare region of the stator ben.'een the two centering pieces 7) and with the two centering pieces 7) at least, into th' constriction, (57) ?Zusammenfaissung Emn Elektromotor bestehlt aus einem diesen dicht umschiiessenden Gehaluse V 1 aus elnem Blechmantei (28) aus nichtrostendem Stahl, einem Stator einer aus demn Ge hiUuse herausgefilhrten \Velle sowie zwei zu beiden Seiten des Stators angeordnetenl Zentrierst~cken die an den Stirnseiten des Stators anliegen und in denen die Wel.

le gelagert 1st, Bei einemn solchen Motor soil das Geh~quse unter lBeibchaltung der bekannten Vortelle hL~heren mechanischeri Belastongen standhalten und dlaraber hinaus mit geringem Aufwand herstelbar sein, Zu diesem Zweck sind die Zentriersttlcke 7) dickwandig, vorzugsweise aus Gussmaterial, ausgebildet und der Aussendurchmesser ist aur der dem Stator zugewandecn Selte gr6sser als der des Stators, wobel die Zentrierstflcke 7) den Stator Cormschltissig ()bergreifen, Die dem Stator abgewandten Endabschnitte (3 1, 32) der Zenilierstcke 7) weiseri mindestens elne Elnschn~lrung aur und der IBlechmantel (28) liegt an dem zwischen den beiden ZentrierstOcken (6, 7) rrelliegenden Igereich des Stators Sowie an den belden Zentriersttlcken 7) zumnindest bis in die Einschnilrung hinein eng an.

Electric Motor The invention relates to an electric motor having a housing which encloses it tightly and consists of a stainless steel sheet jacket, a stator maintained integrally in rotation in the housing, a shaft, at Least one end of which is passed out of the housing, two centring pieces arranged on both sides of the stator, whicn abut J stop at the end faces of the stator and in which the shaft is mounted directly or indirectly.

7 In a known electric motor of the type stated (DE-PS 2,904,384) all the parts which form the housing consist of relatively thin sheet meial. Screw threads which fit into the corresponding screw thread of the next housing S: part are turned or curled into the ends of housing parts to be mutually connected.

15 However, thin sheet metal housings are inadequate for large motors, particularly if the housings are also to be used in underwater operations. When the motor housings are connected to heavy pumps considerable mechanical tens site, compressive and flexural forces occur, which have to 20 be absorbed solely by the housing. Moreover, the housings have to be protected from increased internal pressure and external pressure. Thin sheet steel housings are not suitable for this purpose.

The underlying object of the invention is to produce an electric motor, the housing of which, whilst rep'NL taining the advantages of the known housings, can withstand high mechanical stresses and moreover can be pro- S duced for a small outlay.

1 2 This object is achieved according to the invention in that the centring pieces are of thick-walled construction, that the outside diameter of the centring pieces on the side facing the stator is greater than that of the stator, that the centring pieces embrace the stator positively at its end faces, that the outer end sections of the centring pieces remote from the stator exhibit at Least one constriction, and that the sheet metal jacket closely abuts the region of the stator which is exposed between the two centring pieces, and the two centring pieces, at least into the constriction.

The thick-walled centring pieces, which preferably consist of cast iron and which engage both sides of the S stator give the motor the same mechanical strength and S 15 Lciad capacity in the critical regions as for a motor having a continuous stable cast housing. The motor is moreover coiered with an external layer of stainless sheet steel, so that it is protected from corrosion and may also be im- *I mersed in corrosive liquids for example.

l 20 Due to the particular construction of the centring pieces it is possible for the sheet metal jacket when applied to fix the components of the motor relatively to each other without additional auxiliary means.

The constriction of the centring pieces may be formed by the outer end sections of the centring pieces being reduced in diameter, Ii this case the sheet metal jacket may be applied to the stator and the centring pieces by the pressure rolling process, so that the sheet metal jacket closely abuts the stator and the centring

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3 *9 pieces along its total length, so that good heat transfer exists from the inside outwards and intensive heat dissipation is thus ensured.

Instead of the pressure rolling process, the calibration process or swaging process may also be used to apply the jacket on to the stator and the centring pieces.

The two end faces of the motor may be sealed by end caps made of stainless sheet steel which embrace the sheet metal jacket tightly. For sealing purposes the sheet metal caps exhibit an outward pressed all-round bead, into which an 0-ring is inserted, in their section which embraces the sheet metal jacket.

Separate bearing brackets may be inserted into the centring pieces to mount the shaft. Sealing pieces 15 may be screwed onto the outward facing end faces of the centring pieces, the bearing brackets being fixed between shoulders on the centring pieces on the one hand and the sealing pieces on the other hand.

However, it is al;io possible alternatively for the centring pieces to be integral with the bearing brackets.

In another exemplary embodiment the constriction of the centring wieces may be formed by an all-round groove into which the sheet metal jacket is rolled.

In order to seal the end caps an 0-ring which abuts the siooth inside of the respective end cap may be inserted into the respective all-round groove over the rolled-in sheet metal jacket.

2I The centring pieces may exhibit a second all-round groove, into which the sheet metal jacket is rolled, in -4the region between the all-round groove and the end which abuts the stator. This further increases the mechanical stability of the motor. An 0-ring which abuts the internal surface of an applied cooling jacket may be inserted into said second groove over the sheet metal jacket.

The outer sheet metal jacket may be a preformed tube, which is welded seamlessly or with a longitudinal seam or may also be deep-drawn or pressed out of a disc.

The preformed tube fits positively over the centring pieces and the jacket regions are rolled in or curled in over the stator and the constrictions.

Oil-cooled motors may be constructed so that a bead is curled into th* jacket region over the stator only immediately adjacent to each of the two centring pieces, 15 whereas the jacket section between the two beads remains unformed.

The invention is illustrated by way of example in the drawing and described more fully below with reference j .to the drawing, in which "20 Fig.1 shows in elevation an exemplary embodiment of an electric motor, partly sectioned, Fig.2 shows in elevation another exemplary embodiment of an electric motor, partly sectioned, and Fig.3 shows in elevation a further exemplary embodiment of an electric motor, partly sectioned.

The electric motor 1 illustrated in Fig.1 substan- L ^tially comprises a stator 2, a rotor mounted rotatably 4 relative to the latter anJ mounted on a shaft 3, and a housing 5 tightly enclosing the motor.

Centring pieces 6 and 7, the outside diameter of which is greater than that of the stator 2, are arranged at both ends of the stator 2. The centring pieces 6 and 7 are provided at the end facing the stator 2 with a shoulder 8 with which they embrace positively the respective end face of the stator 2. The stator 2 is thus aligned reliably relative to the centring pieces 6 and 7.

The centring pieces 6 and 7, which consist of relatively thick-walled material, are of pot-shaped construction at their ends facing the stator and embrace the head-shaped winding ends 9 with an interval.

The centring pieces 6 and 7 are provided in their central region with large bores 10 and 11 respectively, S 15 into which separate bearing brackets 12 and 13 respect- S ively are inserted.

The bearing brackets 12 and 13 abut shoulders 14 and 15 respectively of the centring pieces 6 and 7 res- 2 pectively in the axial direction facing towards the stator.

S 20 Outer sealing pieces 16 and 17 respectively are screwed onto the outward facing end faces of the centring pieces 6 and 7; their outside diameter corresponds to that of the centring pieces and they each press with a shoulder 18 and 19 respectively against the outward facing end faces of the bearing brackets 12 and 13 respectively, so that the bearing brackets are fixed between the shoulders 14 and respectively of the centring pieces on the one hand and the f AU shoulders 18 and 19 respectively of the sealing pieces 16 'f and 17 respectively on the other hand.

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6 Set bolts 20, which engage through bores 21 in the sealing pieces 16 and 17 respectively and are screwed into screw-threaded bores 22 in the centring pieces 6 and 7 respectively, serve to fasten the sealing pieces 16 and 17 respectively to the centring pieces 6 and 7 respectively.

The motor shaft 3 is mounted in the bearing brackets 12 and 13 respectively by rolling-contact bearings 23 and 24 respectively.

On the side of the motor which faces downwards in Fig.1, the shaft projects through a bore 25 provided in the outer sealing piece 17 and is passed out fluid-tightly.

On the opposite side the shaft end terminates inside the housing, namely at a short interval from a base 26 of the bearing bracket 12. The base 26 of the bearing 15 bracket 12 serves simultaneously as a support means for S the electrical terminal 27 of the windings.

:i The housing 5, which tightly encloses the entire electric motor, comprises a jacket 28 made of stainless sheet steel and caps 29 and 30, likewise made of stainless .i 20 sheet steel, which embrace the sheet metaL jacket 28 tightly on both sides.

The sheet metal jacket 28 is first of all placed over the centring pieces 6 and 7 as a prefabricated tube.

Because they exhibit a greater diameter than the stator 2, an interstice exilts between the stator and the sheet metal jacket at first. This is eliminated by pressing the sheet metal jacket flush onto the stator in the region between the mutually facing ends of the centring pieces S/ u 6 and 7 by the pressure rolling process.

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7 The outer end sections 31 and 32 of the centring pieces 6 and 7 respectively which are remote from the stator 2 are reduced in diameter so that the sheet metal jacket is located at an interval above these reduced regions. After the central region of the sheet retal jacket 28 has been rolled onto the stator 2, the end sections of the jacket 28 are also pressed against the thinner end sections 31 and 32 of the centring pieces by the same process. Excellent fixing of the components relative to each other is obtained by the sheet metal jacket 28 in this manner. After this the caps 29 and 30 are placed and embrace the pressed ends of the sheet metal jacket positively. For sealing purposes the sheet metal caps 29 and exhibit an outward pressed all-round bead 33, into 15 which an 0-ring 34 is inserted, in their section which embraces the sheet metal jacket 28. For additional sealing, all-round grooves 35, into each of which an 0-ring 36 is inserted for additional sealing, are provided in the outer surfaces of the centring pieces 6 and 7 in the region 20 which faces the sheet metal caps 29 and Additional seals are provided between the bearing brackets 12 and 13 and the centring pieces 6 and 7 on the one hand and the sealing pieces 16 and 17 o'n the other hand. Seals are also arranged all round the passage regions of the set bolts The electrical Lead 37 is passed fluid-tightly through the sheet metal cap 29 and the sealing piece 16.

s The electric motor 38 shown in Fig.2 is construc- S ted similarly to the motor 1 in the exemplary embodiment L i. I- 8 snown in Fig.1. Identical parts are therefore designated by the same reference numerals.

However, the centring pieces 6 and 7 which abut the stator 2 exhibit a somewhat different shape. The centring pieces are each provided at an interval from their end which abuts the stator 2 with an all-round groove 39 into which the sheet metal jacket 28 is rolled. The function of the all-round grooves corresponds approximately to the end sections 31 and 32, provided with a reduced cross-section, of the centring pieces shown in Fig.1. The axial cohesion of the motor parts is ensured by rolling the sheet metal jacket 28 into the all-round grooves 39.

0-rings 40 which are inserted into the all-round grooves 39 form a seal element relative to the caps 29 and 30 fitted S 15 on both sides. In this exemplary embodiment the ends of the caps 29 and 30 which are fitted onto the centring pieces are of smooth cylindrical construction, whilst the 0-rings 40 abut the insides of the cylindrical cap ends.

The centring pieces 6 and 7 are provided with a 20 further all-round groove 41 in the region between the allround groove 39 and the rotor 2 into which the sheet metal jacket 28 is rolled. The axial cohesion is improved by this further groove. This second groove 41 also has a further function. In the exemplary embodiment shown in Fig.2 the central region of the motor is enclosed by a cooling jacket 42 made of stainless sheet steel. As shown in the upper region of Fig.2, an 0-ring 42 may be inserted into Sthe all-round groove 41, whereby the edge of the cooling jacket 42 can be sealed relative to the motor housing.

I i~ii. 0-

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9- The electric motor 44 shown in Fig.3 relates to an exemplary embodiment with an oil cooling system. The two centring pieces 45 and 46 which abut the stator 2 are constructed integrally with the bearing brackets. The two centring pieces 45 and 46 are identical and are fitted in opposite positions to each other.

The sheet metal jacket 28, as a preformed tube, is fitted positively over the centring pieces 45 and 46 and, from outside, a bead 47 or 48 respectively is curled in over the stator 2 only in the region directly adjacent to the two centring pieces 45 and 46, the jacket section 49 between the two beads 47 and 48 being left substantially unformed. An interstice into which cooling oiL can penetrate is provided between the sheet metal jacket 28 i 15 and the stator 2 in this region.

S .The axial cohesion of the individual parts of the motor is effected by rolling the sheet metal jacket into all-round grooves 50 which are turned into the outer circumference of the centring pieces 45 and 46 just before 20 their outer ends. The grooves 50 are provided with a bevel 51 on the side facing the stator 2, so that the sheet metal jacket 28 can be rolled into the groove easily. The other side of the groove exhibits a wall 52 extending at right S angles to the axis of the centring pieces, which forms a sharp edge together with the outer circumferential surface of the centring pieces. This edge co-operates with a cutting roller when the sheet metal jacket 28 is applied, l so that the sheet metal jacket is cut to length S/K simultaneously.

10 0-rings 53, which are inserted into the aLL-round grooves 50, seaL the end caps 29 and 30 respect iveLy reLative to the centring pieces 45 and 46 respectively.

6 to to **to **of I 11 List of references 1 electric motor 2 stator 3 shaft 4 rotor housing 6 centring piece 7 centring piece 8 sh;,ulder 9 head-shaped winding ends bore 11 bore 12 bearing bracket 13 bearing bracket 14 shoulder shoulder 16 sealing piece S17 sealing piece 18 shoulder 19 shoulder .20 set bolts 'J 21 bores 22 screw-threaded bores 23 rolling-contact bearing 24 rolling-contact bearing 25 bore S26 base 27 electrical terminal 28 jacket 29 cap cap 31 end sections 32 end sections 33 all-round bead 12 34 0 -r in g all-round groove 36 0 -r in g 37 electrical lead 38 electric motor 39 all-round groove 0 -r in g 41 all-round groove 42 cool ing jacket 43 0 -r in g 44 electric motor centring piece 46 centring piece 47 bead 48 bead 49 jacket section all-roi~nd groove 51 bevel 0 o:52 Vertical Wall .53 0-r ing9s :f 0

Claims

1. An electric motor 38; 44) having two end faces and having a housing which encloses the motor tiqhtiy and consists of a sheet metal iacket a stator (2) maintained fixedly in the housing a shaft at least one end of which passes out of the housing and two cen'ering pieces 7; 45, 46) arranged on both sides of the stator which have an outside diameter on the side facing the stator which is greater than the stator which embrace the stator positively at its end faces, which abut a stop at the end faces of the stator and which are formed for mounting the shaft, characterized in that the sheet metal jacket (28) consists of stainless steel, that the centering pieces 7; 45, 46) are of thick. .d construction and include outer end sections remote from the stator and which exhibit at least on constriction, that the sheet metal jacket (28) closely abuts a region of the stator which is exposed between the two centering pieces, and the two centering pieces 7; 45, 46), and the sheet metal jacket tightly engages the constriction, and that the two end faces of the motor 38; 44) are sealed by end caps (29, 30) made of stainless steel which embrace the sheet metal jacket (28) tightly, and bearing brackets are inserted into the centering pieces to mount the shaft. 2 An electric motor according to claim 1, characterized in that the constriction of the centering pieces 7) is formed by the outer end sections (31, 32) of the centering pieces being reduced in diameter. to 3 An electric motor according to claim 1 or 2, characterized In that the sheet metal jacket (28) is applied to the stator and the centering pieces 7) by pressure rolling. I S* 4. An electric motor according to claim 1 ur ,haracterized in that the end caps (29, 30) exhibit an outward pressed all-round bead into which an O-ring (34) Is inserted, in their section which embraces the sheet metal jacket (28), An electric motor according to claim 2, characterized in that the bearing brackets (12, 13) are separate and are inserted into the centering pieces 7) to mount the shaft te' r~ P~ P 14

6. An electric motor according to claim 5, characfterized in that sealing pieces (16, 13) are screwed onto outward facing end faces of the centering pieces 7) and that the bearing brackets (12, 13) are fixed between shoulders (14, 15) on the centering pieces 7) and the sealing pieces (16, 17).

7. An electric motor according to claim 1, characterized in that the constriction of the centering pieces 7; 45, 46) is formed by an all-around groove (39, 50) into which the sheet metal jacket (28) Is rolled.

8. An electric motor according to claim 7, characterized in that an O-Ring (40; 53) abuts a smooth inside surface of each end cap (29, 30) and is inserted into the all-round groove (39; 50) over the sheet metal Jacket (28).

9. An electric motor according to claim 7 or 8, characterized in that the centering pieces 7) exhibit a second all-round grooved into which the sheet metal jacket (28) Is rolled, in the region between the all-round groove (39) and the end which abuts the stator and that an Oring (43) which abuts the internal surface of an applied cooling jacket (42) is inserted into said groove (41) over the sheet metal jacket. An electric motor according to claim 1, 2, 5, 6, 7 or 8, characterized in tnat the S, sheet metal jacket (28) is a preformed tube which fits positively over the centering pieces (45, 46) and that portions of the sheet metal Jacket are rolled in [or curled in] over the stator and the constriction. 1. An electric motor, according to claim 10 having an oil cooling system, characterized in that a bead (47, 48) is curled in a portion of the sheet metal jacket over the stator only immediately adjacent to each of the two centering pieces 46), whereas another portion (49) of the sheet metal jacket [section between the wo beads is unformed. S. 12, electric motor according to claim 1, characterized In that the constriction of the c marlng pieces 7; 45, 46) Is formed by an all-around groove (39; 50) into which the sheet metal jacket (28) Is curled.

13. An electric motor according to claim 1, 2, 5, 6, 7 or 8, characterized in that the sheet metal jacket (28) is a preformed tube which fits positively over the centering pieces (45, 46) and that portions of the sheet metal jacket are curled over the stator and the constriction.

14. An electric motor according to claim 1. substantially as herein described with reference to the accompanying drawings. DATED this 19th day of February 1992 ALBER BLUM WATERMARK PATENT TRADEMARK ATTORNEYS THE ATRIUM 290 BURWOOD ROAD HAWTHORN VICTORIA 3122 AUSTRALIA DOC 010 AU2533188.WPC LJD/RCTS/BS S9o g i 9 *9 9 9. 1 a 4* 9 9 1