DE2447155A1 - ELECTRIC MOTOR AND METHOD OF ITS MANUFACTURING - Google Patents

Description

OR.-INS. DIPL-INS. M. SC. DIPL.-PHY ». OR DIVL -Pt- (VS

HÖGER - LEGAL RIGHTS - GRIESSBACH - HAECKER

PATENT LAWYERS! N ST

Λ 40 872 b

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2nd September 1974

Warner Electric Brake & Clutch Company

Electric motor and process for its manufacture

The invention relates to an electric motor with a stator arrangement with a stator carrying at least one winding and having a plurality of pole pieces which are circumferential with respect to an axis are arranged at a distance from one another and extend in the radial direction and the inner ends of which are essentially one limit cylindrical inner chamber concentric to the axis and a method for producing such an electric motor.

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In particular, the invention is concerned with the design of the Stator arrangement of an electric motor, which can be assembled with a rotor and with a manufacturing method for such a stator arrangement.

In the known electric motors, ground on a stator, which is usually composed of a large number of sheet metal lamellas is attached, windings and the resulting filter assembly is then placed in a tubular housing built in, the open ends of which are later closed by metal end caps that are very carefully machined must so that on the one hand they fit exactly on the ends of the tubular metal housing and on the other hand for the precise Storage of the bearings are suitable for the rotor shaft, which must be precisely aligned with respect to the stator assembly along the entire circumference of the rotor, as uniform as possible To maintain air gap. In summary, it can be stated that the housings of known electric motors are heavy and are expensive and that the manufacture of the known electric motors, in particular the manufacture and processing of the metallic end caps of the housing is time consuming and expensive.

Based on this prior art, the invention is based on the object of a robust electric motor and a method to propose to its manufacture, with which manufacture; costs and the flontage effort can be greatly reduced.

This task is accomplished by an electric motor of the type described at the outset Type solved, which is characterized by

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that the stator assembly is embedded in a one-piece plastic body with a recess in the inner chamber, in the Bearing housings which are concentric to the axis of the inner chamber and located in the region of the ends of the same are embedded.

Such a motor can be produced simply and cheaply, preferably in a process which comprises the following process steps:

a) The stator arrangement with the at least one winding is pushed onto a core in such a way that it is coaxial in the cylindrical inner chamber of the stator arrangement lies;

b) A shape is built around the stator assembly with the core, which is designed so that there is between their inside and the free surfaces of the stator assembly give gaps;

c) pushed onto the core v / earth bearing housing in such a way that they are a predetermined distance in the axial direction have from each other and on the inside of axially spaced apart molded parts of the mold lie;

d) the mold is essentially completely filled with flowable plastic material;

e) the plastic material is allowed to harden and

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f) the core and the mold are removed.

In the encapsulated stator arrangement obtained in this way, or embedded in a plastic housing, can then easily and
simply the rotor of the electric motor with its bearings are used, which are inserted into the precisely aligned bearing housing and are usually secured against axial displacement in these.

It is an advantage of the method and engine according to the invention, that the difficulty and expense of accurately machining and assembling the metal end caps are connected in the known electric motors are omitted.

It is a further advantage of the method and motor according to the invention that the entire stator arrangement is essentially a one-piece, solid structure, so that the finished
The electric motor is exceptionally robust and insensitive to corrosion or the like, as can occur with conventional electric motors in the appropriate environment.

Another advantage is that the bearing housing is simply at the correct distance and coaxial to the rotor shaft can be attached, so that difficult adjustment and adjustment work is not necessary during the final assembly of the motor.

Further details and advantages of the invention are provided below explained in more detail with reference to a drawing and / or are the subject of the claims for protection. In the drawing show:

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Fig. 1

and FIG. 1a shows a side view (partially in section) or

an end view of a conventional electric motor;

Fig. 2 is a perspective view of the stator a laminated core forming an electric motor including the windings attached thereon;

Fig. 3 is a side view (partially in section) of a preferred embodiment of a motor according to the invention to illustrate the method for the manufacture of such a motor and the arrangement of its individual parts;

Fig. 4 is a side view (partly in section) of a preferred embodiment of a bearing housing connected to the stator for a motor according to FIG the invention;

Fig. 5 is a side view (partially in section) of the

Stator assembly of a preferred embodiment a motor according to the invention;

6 shows a cross section through the stator arrangement according to FIG. 5 along the line 6-6 in this figure;

Fig. 7

and FIG. 7a shows a side view (partially in section) or

an end view of an engine according to the invention;

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Pig. 8 shows a partial longitudinal section through a modified one

Embodiment of a motor according to the invention;

9 is a side view of a further modified one

Embodiment of a motor according to the invention with a to improve the cooling effect in specially designed stator and

Fig. 10

and FIG. 10a shows a plan view and an end view of a

further modified embodiment of a motor according to the invention, the stator of which in is specially designed to facilitate its assembly or its attachment to a bracket.

Before going into more detail below on the individual figures of the drawing, let it be said that below only Preferred exemplary embodiments are explained and that the invention does not apply to these specific exemplary embodiments is limited. Rather, the claims should cover all modifications, alternatives and equivalents, which fall under the basic idea of the present invention, as it emerges from the application documents for a person skilled in the art.

In the construction typical of previously known engines, it has been common to manufacture the stator assembly in such a way that Polblechpakete and coils have been installed very accurately in an outer tubular casing whose open ends are then closed by ge separates prepared end caps at the

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tubular housing were attached. In the End caps incorporated with high precision circular openings, into which bearing housings were pressed. Furthermore, the rotor and its shaft have been precisely aligned with the help of Bearings rotatably mounted and supported, which are spaced along the rotor axis at a distance from one another and concentric to the rotor axis were arranged. A typical prior art motor of this type is shown in FIGS. 1 and 1a. In the known engine there is the Stator assembly of four separate parts, namely a tubular housing 15, a laminated core 16 for the stator, electrical windings 17 on the laminated core and end caps and 18a. The end caps 18, 18a have machined edge regions 20 and 20a which fit tightly and precisely into one another opposite ends of the tubular housing 15 fit. Furthermore, the end caps 18,18a are provided with machine-machined central bores 21, 21a, which after the attachment of the End caps 18, 18a on the tubular housing 15 are exactly coaxial with one another and a predetermined one in the axial direction Distance from each other, as is clear from the drawing. Bearing housings 22 or 22a used in a press fit. After a rotor 24 has been inserted into the cylindrical inner chamber of the laminated core 16, bearings 25, 2.5a are pushed over the ends 26, 26a of the rotor shaft and pressed into the bearing housing 22 or 22a and secured there by means of spring clips, in particular with so-called Spring washers 28 and 28a.

Since the bearings are exactly coaxial in the manner described above are arranged to each other, results in a concentric

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Position of the surface of the rotor 24 with respect to the inner ends of the pole pieces of the laminated core 16 and thus a uniform air gap for the magnetic flux from the laminated core to the rotor and back. As FIGS. 1 and 1a show, the electrical leads 29 from the windings 17 are led out of the stator arrangement through an opening in the end cap 18, a protective, elastic sleeve being arranged in this opening. The other end cap 18a can be provided with a plurality of threaded bores 30 arranged at a distance from one another in the circumferential direction, into which fastening screws can be screwed which hold the motor on a flange of a machine to be driven.

It is clear that the presence of separate end caps 18 and 18a as well as the need for precise machining of the edge areas 20, 20a and the central openings 21, 21a in connection with the subsequent assembly work for attaching the end caps to the tubular housing 1 5 takes up considerable labor times and Causes costs.

As will be apparent from the following description, these disadvantages are overcome by the method and the design principle according to the invention, and one obtains an extremely robust electric motor, in which no separate metallic end caps are required, so that accounts for their machining and assembly.

It should first be assumed that the stator arrangement shown in FIG. 2 comprises a stator packet which consists of individual sheets of magnetically permeable steel. When the

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Stamped sheets are stacked and pressed together, they form a substantially cylindrical stator core 32. Each of the mutually aligned metal sheets has alternately successive projections and along its inner circumference Gaps. As a result, a stator package with a plurality of pole pieces 34 is formed which, with respect to a longitudinal axis 33 in FIG run in the radial direction. The pole pieces 34 have inner ends 34a which have a substantially cylindrical inner chamber 35 limit. The inner chamber 35 is concentric with the longitudinal axis 33, and the pole pieces 34 are in the circumferential direction Arranged at a distance from one another around the longitudinal axis 33. To magnetically excite the pole pieces 34 and a magnetic flux to generate, which starts from the ends 34a of the pole pieces, or returns into these, is on each pole piece 34 a electrical winding 17 attached, the longitudinal parts of which in the spaces between the respective Pole piece 34 and the adjacent pole pieces 34 lie. The individual windings 17 can be different series or Series-parallel circuits are connected to one another in order to obtain one or more phases in this way. the However, details of the circuit of the windings are not of interest in connection with the present invention. Suffice it to say that the stator assembly 32 includes at least one electrical winding, at least one of which a conductor can be connected to a supply voltage source.

According to the invention, the stator assembly 32 is with a Surrounding hardenable plastic housing, which is designed at the same time so that it can accommodate the bearing housing and precisely able to align. To achieve this, the stator

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Order 32 is arranged on a core 36 (Fig. 3), which fits exactly into the inner chamber 35, which is defined by the inner surfaces of the ends 34a of the pole pieces 34. As is clear from FIG. 3, the core 36 is preferably provided with two projections 38 which are arranged resiliently in the radial direction and which have a predetermined spacing from one another in the axial direction. The projections 38 protruding in the radial direction are arranged in radial bores of the core 36 and are biased outward by springs 39. Due to the construction described, it is possible to push the bearing housing 40, the inner diameter of which is only slightly larger than the outer diameter of the core 36, onto the core until the projections 38 snap into an annular groove 41 of the associated bearing housing 40 (FIG. 4). The bearing housings 40 are preferably knurled or otherwise provided with an uneven surface on their outside, so that a stronger connection to the plastic material results, as will be explained below.

If a collar 36a is provided on the core 36, as shown in FIG. 3, specifically at the right end of the core 36, then the right end disk or part 42a of a mold 42 can first be pushed onto the core 36 from left to right until it rests against the collar 36a. Subsequently one of the bearing housing 40 can then be so much pushed onto the core 36 until the projection 38 in the vicinity of the right end in the annular groove 41 of the bearing housing 40 is incident. The stator arrangement 32 can then then be pushed onto the core 36 from left to right until it rests with its right end on the bearing housing 40 in the position shown. Thereafter

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the second bearing housing 40 can be slid onto the core 36 until the projection 38 is near the right end of the core 36 engages in the annular groove 41 of this bearing housing 40. It then becomes a cylindrical. Molded part 42b pushed over the stator assembly 32 until positioning pins 42c from the end plate 42a into associated bores of the cylindrical Engage housing part 42b. In some cases it may be desirable to have the cylindrical housing portion 42b made up of two Assemble half-cylinders to make it easier to open the mold, which can then take place in the area of the dividing line of the half-cylinder. Eventually it will be circular End plate 42d, which also forms a section of the assembled mold 42, pushed over the left end of the core 36, to positioning pins 42e on their inside in associated openings at the left end of the cylindrical molded part 42b intervene. Support the two end disks 42a, 42d in the assembled form against the outer ends of the associated bearing housing 40.

In the manner described it is achieved that the mold 42 completely surrounds the stator arrangement 32, except on the inside, which delimits the inner chamber 35 in which the core 36 is located. The inside of the mold 42 has one Distance from the outside of the stator arrangement 32. In detail, the drawing shows that between the inner surface of the cylindrical molded part 42b and the outer surface of the stator arrangement 32, a gap 45 remains radial direction is relatively low. It can also be seen that between the end faces of the stator assembly 42 and the inner ^ · on the sides of the end disks 42a, 42d, cavities 46 and 47 remain,

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which are delimited along their inner circumference essentially by the bearing housing 40. Finally, the interspaces between the individual pole pieces 34 are still present, which _B, insofar as they are not filled with the windings 17, open at their ends to the cavities 46 and 47.

In a preferred Äusfiihraßgsform the finished motor by means of screws is secured "to a flange of the machine to be driven In theseA cases the assembly can be made easier if spaced at an end face of the finished motor in circumferentially spaced threaded bores providing ,, ϊ · η For this purpose, the end disk 42a of the foria 42 holds several bores 42f arranged at a distance from one another in the circumferential direction , into which the areas of threaded bolts 49 are inserted, which in turn are screwed into threaded parts of single metal cylinders. In the cavity 47 there is thus a number of metal cylinders which are fixed in predetermined positions.

Finally, the end plate 42d can be provided with an opening 42g through which the supply lines to the windings 17 can be passed when the end plate 42d is in its, shown in FIG. 3 position shown is brought. In this way, the connection of the turns 17 in the stator arrangement 32 is facilitated. Preferably, the leads are surrounded by a sleeve 51 which _f partially in the opening 42g protrudes and which is later injected into the cavity 46 so that the leakage of plastic material is prevented.

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The mold 42 is provided with a filling opening which allows the filling or injection of flowable plastic material serves. In addition, the mold 42 has one or more small ventilation openings through which air and excess Plastic material can escape. At the observed In the exemplary embodiment, the cylindrical molded part 42b is provided with a filling opening 42h which has a funnel-shaped mouthpiece is provided, in which the plastic material can be poured or injected. At the other end of the Form 42 has the end plate 42d ventilation openings 42i and 42j of relatively small diameter, through which excess Quantities of the injected plastic material can escape.

When the mold 42 is assembled in the manner described with the formation of the various cavities and spaces around the stator assembly 32, the next manufacturing step is that flowable plastic material is injected into the mold 42 until the spaces mentioned between the mold 42 of the stator assembly 32, the core 36 and the bearing housings 40 are substantially filled. During the injection of the plastic material, the end plate 42d can be pressed in the axial direction against the right end of the cylindrical molded part 42b with the aid of suitable devices (not shown) or kept in close contact with it, while the cylindrical molded part 42b is firmly against it the right end disk 42a is supported. As plastic materials, all known plastics come into question, which in terms of electrical. Insulation, shock resistance and resistance to chemicals have the desired quality. The flowable plastic material injected into the mold 42

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is, for example, an epoxy resin, which is a Contains hardener or a polyamide material that solidifies and hardens. Depending on the viscosity of the Plastic material can be filled with or without pressure until substantially all of the cavities in the mold are filled and plastic material passes through the vents 42i, 42j exits. It goes without saying that when injecting plastic material through the filling opening 42h, not only the Gap 45 and the cavities 46 ,. 47 are filled, but also the spaces remaining after the windings 17 have been inserted between the pole pieces 34. For the sake of simplicity, the plastic material in the figures of the drawing is associated with the Reference numeral 55 denotes because after the injection end it forms the mold as a continuous one-piece body.

After the mold 42 has been filled, the plastic material 55 is allowed to harden. The curing can simply take place at room temperature, which takes a few hours, or at an elevated temperature, depending on which plastic material is used. After curing, the molded parts 42a, 42b and 42d are removed and the core 36 is pulled off in the axial direction. Obtained in this way a free Innenkamraer 35. The projections 38 enter the core 36 in accordance with or be "forced radially inwardly when the core is pulled out in the longitudinal direction of the inner chamber 35, 36 'it being understood that"' the bearing housings 40 now vora the hardened plastic material 55 umea ψαύ are firmly connected to this.

After removal from the mold, there must be a stator assembly, as shown in FIG. 5, which is the core of the stator

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thereby from the one-piece body made of hardened plastic material 55 and is securely held by it. This results in an extreme mechanical strength due to the fact that the one-piece plastic body is also in the spaces between the pole pieces 34 or the windings 17 protrudes, the plastic material 55 at the same time envelops the entire outer surface of the stator and forms protective end walls of finite thickness which are relatively strong. After removing the moldings and the core will be the threaded bolts 49 are unscrewed from the metal cylinders 50 and the latter are now firmly embedded in the plastic material and are available for screwing in fastening screws. Furthermore, the bearing housings 40 are also on the opposite ends of the inner chamber 35 are similarly fixed in the one-piece body of plastic material 55 embedded. The bearing housings 40 are aligned exactly concentrically with respect to the longitudinal axis 33, wae through the described shape of the core 36 is achieved, and also have the desired spacing from one another in the axial direction, which is achieved by the projections 38 on the core 36. The bearing housings 40 are therefore located exactly in the correct location to the bearings for a rotatable mounting one Take up the rotor shaft.

As is particularly clear from Fig. 6, the hardened is sufficient Plastic material 55 in the radial direction into the spaces between the pole pieces 34 and has an interface, which is substantially aligned with the inner ends 34a of the pole pieces 34. The finished stator assembly thus has a central cylindrical inner chamber 35 with a substantially

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Lichen cylindrical wall, the diameter of which is equal to the distance between diametrically opposite ends 34a of pole pieces 34 1st. Since the bearing housing 40 is concentric to The longitudinal axis 33 of the inner channels 35 leads to the subsequent Assembly of a rotor in the inner chamber, as will be explained below, to form a uniform radial air gap between the outer surface of the rotor and the inner surface of the stator.

In order to obtain a fully assembled motor, as shown in FIGS. 7 and 7a, it is now only necessary to insert a rotor 56 in the axial direction into the stator arrangement, where the rotor is supported by bearings and secured in the axial direction. As FIG. 7 shows, the rotor 56 has a first part which has a first diameter which is slightly smaller than the diameter of the inner chamber 35, and end parts whose diameter is smaller than the diameter of the first part. The rotor 56 may in the longitudinal direction in such a way in the inner chamber 315 are pushed in, that its mean or first part, which, for example, a permanent magnet or may be a stack of toothed laminations, in the region of the lamination stack of the stator assembly 32 is located. Anschlies- then send low-friction bearing 60 can 56a and 56b of the rotor shaft are slid, and are inserted into the two bearing housing 40 in the axial direction to the ends. To secure the bearings 60 in the bearing housings 40 in the axial direction, spring clips can then be inserted into the annular grooves 41 (FIG. 4) of the bearing housings 40. In this way, the rotor is secured in the axial direction and is rotatably mounted between the pole pieces 34 of the stator arrangement.

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In some cases it may be desirable instead of a motor in which the ends of the windings 17 simply follow are externally guided to provide a motor with plug-in connections for the windings. In this case you can just do one Provide plug or socket block, as shown in Fig. 8 top left. As Fig. 8 shows, the end plate is 4 2d, which forms part of the mold 42, for this purpose on its inside with projections protruding in the axial direction 62 provided, on which the metal sockets of the socket block 64 plugged v / ground before the end plate 42d in a Position is moved in which it closes the mold 42. The metal frames are suitable, for example through Solder connected to the corresponding lines of the motor winding. If the socket block in the manner described is retained in the form when the plastic material 55.in If the cavities between the mold and the stator assembly are injected, the socket block is cast in the correct position and held securely in the cured plastic material. Later, a cable with a plug can be used easily be inserted into the metal sockets of the socket block in order to establish the desired connection between the motor windings and the supply voltage source to manufacture. It goes without saying that instead of a socket block, a plug block is also cast in can, to which then the connection with the help of an appropriate Socket arrangement can be produced.

As mentioned above, the windings 17 of the finished motor are available in close contact with the hardened plastic material 55 and are surrounded by this, as far as they do not rest on the inner sides of the pole shoes 34 (Fig. 6). Any warmth due to

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of currents flowing through the windings 17 is thus either on the laminated core of the stator or in the Transfer plastic material. Of course, the laminated core is also in close contact with the plastic material 55, so that the heat from the laminated core is also given off to the plastic material 55. Although the plastic material in general is not exactly an excellent conductor of heat, its large contact surfaces lead to the laminated core and the windings as well as its large outer surfaces for excellent heat dissipation into the atmosphere. The heat dissipation can can be further improved by enlarging the outer surface of the hardened plastic body. A corresponding modified embodiment is shown in Fig. 9, where the plastic body of the finished stator assembly with cooling fins 70 is provided, which are obtained with the aid of correspondingly designed molded parts 42a, 42b and 42d. In advantageous Embodiment of the invention is the heat transfer from the inside of the stator to the outside of the same through use improved by molded parts which have uneven inner surfaces and which to a finished stator assembly lead, which is provided on its outer surface with cooling fins or the like.

Furthermore, in an embodiment of the invention, it is possible to have fastening devices which are integrally formed on the cured plastic body to make it easier to mount the finished motor on a suitable carrier. Like Fig. 10 and 10a show, can on the outer surface of the one-piece Synthetic body at one end of the same three radially protruding flange areas provided with an opening

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72a, 72b and 72c can be provided. The flange areas can be used to accommodate fastening screws, with their help the motor is firmly attached to a machine frame or the like. Instead or in addition, the plastic body the stator assembly can be provided with molded feet 74a and 74b, as also shown in FIGS. 10 and 10a is. When the motor is to be mounted on a flat surface that is parallel to its outgoing shaft it is only necessary to insert the fastening screws through the openings at the ends of the feet-74a, 74b are provided. It goes without saying that the formation of flange parts 72a to 72c and feet 74a, 74b by means of suitable Shaping the corresponding parts of the shape described above is achieved. When molding fastening parts However, you will assemble the cylindrical molded part 42b from two or more sections, so that this after Hardening of the plastic material can be easily removed.

From the above description it is clear that gemass According to the invention, an electric motor is proposed in which no more metal parts are provided to a housing form. The entire housing, which contains and supports the stator assembly with the laminated core and the windings, is rather, formed by a one-piece body made of hardened plastic material. This prevents the engine from rusting and protected from damage from corrosive chemicals. At the same time, however, what is even more important, the Necessity, expensive and precisely machined metal end caps and a matching tubular one with a great deal of labor Manufacture housing. Even so, the bearing housings and the bearings they hold are precisely aligned so that they

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precisely support the ends of the rotor shaft that carries the rotor, which rotates inside the stator assembly while maintaining a predetermined air gap.

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Claims (24)

Patent claims: 1) Electric motor with a stator arrangement with a stator carrying at least one winding with several Pole pieces that are circumferentially spaced from one another with respect to an axis and in run in the radial direction and the inner ends of which are essentially cylindrical and concentric to the axis Bounding the inner chamber, characterized in that the stator arrangement (32) with the recess of the Inner chamber (35) is embedded in a one-piece plastic body (55), .in to the axis (33) of the inner chamber (35) concentric bearing housings (40) lying in the region of the ends thereof are embedded. 2) Electric motor according to claim 1, characterized in that the stator is composed of individual lamellae is. 3) Electric motor according to claim 1 and 2, characterized in that the plastic body (55) is the spaces between the pole pieces (34) is essentially filled. 4) Electric motor according to claim 1 to 3, characterized in that the plastic body (55) end walls of limited thickness. - 22 - 509815/0416 Λ 40 872 b k - 163 September 2, 1974 - 22 - 2 * 47155 5) Electric motor according to claim 1 to 4, characterized in that the material of the plastic body (55) ■ in the area of the inner chamber (35) essentially in one Plane with the inner ends (34a) of the pole pieces (34) and together with the ends (34a) of the pole pieces (34) forms a substantially smooth cylindrical wall of the inner chamber (35). 6) Electric motor according to claim 1 to 5, characterized in that the plastic body (55) has an outer surface has a given shape and, together with the Stator assembly (32) and the bearing housing (40) all cavities between its outer surface and the wall of the inner chamber (35) fills. 7) Electric motor according to claim 1 to 6, characterized in that the plastic body (55) with cooling fins (70) or the like is provided to improve the heat dissipation (Fig. 9). 8) Electric motor according to claim 1 to 7, characterized in that fastening devices (metal cylinder 50) are provided in the plastic body. 9) Electric motor according to claim 1 to 8, characterized in that at least one lead to the at least one winding (17) of the stator arrangement (32) is passed through the plastic body (55) to the outside. - 23 - 509815/041 6 A 40 872 b. :: k - 163 September 2, 1974 -23- 2447155 10) Electric motor according to claim 1 to 9, characterized in that a connection block in the plastic body (55) (64) is embedded, which comprises externally accessible contacts that are connected to the at least a winding (17) are connected. 11) Electric motor according to claim 1 to 10, characterized in that that a rotor (56) is provided which, in its central area, has a section with a has a first diameter which is slightly smaller than the inner diameter of the inner chamber (35) and which has a rotor shaft whose ends (56a, 56b) have a diameter on iron which is smaller than that Diameter of the inner chamber (35) and that bearings (60) are provided, which are detachable in the bearing housings (40) are secured and which the ends (56a, 56b) of the shaft of the rotor (56) rotatably support. 12) Electric motor according to one or more of the preceding claims, characterized in that the Plastic body (55) is provided on its outside with fastening devices (72a to 72c; 74a, 74b) (Fig. 10, 10a). 13) Method of making an electric motor according to one or more of claims 1 to 12, characterized by the following process steps: - 24 - 50 9815/0416 A 40 872 b ^: j ■ ^; k - 163 September 2, 1974 - 24 - 2447155 a) The stator arrangement (32) with the at least one winding (17) is in such a way on a remote (37) pushed so that this coaxially in the cylindrical inner chamber (35) of the stator arrangement (32) lies; b) around the stator arrangement (32) with the core (36) a mold (42) is built up, which is designed in this way is that between its inside and the free surfaces of the stator assembly (32) Result in gaps (45, 46, 47); c) Bearing housings (40) are pushed onto the core (36) in such a way that they have a predetermined distance from each other on v / iron and on the inside of axially at a distance from each other arranged mold parts (42a, 42d) of the mold (42) lie; d) the mold (42) is at least substantially complete filled with flowable plastic material; e) the plastic material is allowed to harden and f) the core (36) and the mold (42) are removed. 14) The method according to claim 13, characterized in that the core (36) and the mold (42) are formed - 25 - 509815/0416 A 40 872 b '.. k - 163 λ / ι η λ CC Sept. 2, 1974 - 25- '^ HHfNJ that the core (36) is tightly enclosed by openings at opposite ends of the mold (42) will. 15) Method according to claim 13 and 14, characterized in that that the shape (42) is designed so that between the end faces of the stator assembly (32) and the inner end faces of the mold (42) result in cavities (46, 47) which, based on the common axis (33) of the stator assembly (32) and core (36) have a considerable diameter. 16) Method according to claims 13 to 15, characterized in that that the bearing housings (40) are mounted on the core (36) at such an axial distance that each of the bearing housings (40) at least part of the radially inner wall of the cavities (46, 47) forms. 17) Method according to claim 13 to 16, characterized in that on the core (36) compliant in the radial direction Projections (38) are provided which are spaced a predetermined distance from one another in the axial direction have, which corresponds to the desired axial distance between the bearing housing (40) and that the bearing housing (40) are pushed onto the core (36) until the assigned projection (38) into a corresponding recess (41) or the like of the respective bearing housing (40) engages and this with respect to the core - 26 - 509815/0416 Λ 40 872 b k - 163 _Λ September 2, 1974 - 26 - 244 7 I. (36) positioned in the longitudinal direction. 18). Method according to claim 17, characterized in that that the projections (38) are formed in such a way that they one after the hardening of the plastic material Allow withdrawal of the core (36) from the stator assembly (32) in the axial direction. 19) Method according to claim 13 to 18, characterized in that that when building the mold (42) around the stator assembly (32) in the axial direction at a distance molded parts (42a, 42d) arranged from one another are placed against the outer ends of the bearing housing (4O) will. 20) Method according to claim 13 to 19, characterized in that that a mold (42) with an opening (42g) is used through which supply lines to the at least one winding (17) can be passed through to the outside of the mold. 21) The method according to claim 13 to 20, characterized in that the Kunststof firaterial under pressure in the mold (42) is filled. 22) Method according to claim 13 to 21, characterized in that that the plastic material so in the Form (42) is filled in that the spaces between the pole pieces (34) so / eit not through - 27 - 509815/0416 Λ 40 872 b - k - 163 September 2, 1974 - 27 - 2447155 the one or more windings (17) are filled, filled with plastic material v / earth to a better, form-fitting connection between the stator assembly (32) and the hardened plastic body (55) and to achieve a better heat transfer from the stator arrangement (32) to the plastic body (55). 23) Method according to claim 22, characterized in that that the spaces between the pole pieces (34) so. be filled far that the plastic material between the pole pieces (34) comes into contact with the core (36), so that after removal of the Core (36) for the inner chamber (35) results in a substantially smooth cylindrical wall, which through the inner ends (34a) of the pole pieces (34) and intermediate parts of the plastic body (55) are formed will. 24) Method according to one or more of claims 13 to 23, characterized in that at least one Inner surface of the mold (42) is provided with projections and incisions, so that the hardened Plastic body (55) cooling fins (70) or the like result, through which the heat dissipation is improved. 509815 / 0A16 ι ^X * Blank page