DE29510521U1 - Rotor for electrical machines and devices, in particular stepper motors - Google Patents

Description

: PATENT ATTORNEY

TDIPL-ING. KLAUS-JÜRGEN SCHWARZ

PATENT ATTORNEY SCHWARZ, GLUCKSTRASSE 7, D-53115 BONN EUROPEAN PATENT ATTORNEY

Applicant; 28 June 1995

MAGNET PHYSICS

Dr. Steingroever GmbH

Emil-Hoffmann-Str. 3

50996 Cologne

VNR: 108 545

ATTORNEY FILE
2 894/95

Description

Rotor for electrical machines and devices, especially stepper motors

The invention relates to a rotor for electrical machines and devices according to the preamble of claim I ₇ which is particularly suitable for stepper motors.

Such rotors for small electrical machines and devices, such as stepper motors in particular, usually consist of a large number of individual parts that are painstakingly assembled into a complete structure and, after the permanent magnet bodies have been glued to the iron core, must also be coated with plastic or secured with a bandage, e.g. made of glass fibre fabric. Even with precise manufacture of the permanent magnet bodies, an inaccurate adhesive gap can result, in connection with contamination of the production machines and environmental pollution from adhesive fumes. A heated, thin-walled tube can then be shrunk on as an outer sleeve. This requires not only

G!uck»tra6e 7 Telephone: (0226) 659091 -I- 6590&THgr;2 Deutsche Bank AQ Bonn Postbank KAIn D-53115 Bonn Telegrams: Bonnpatent Bonn * (bank code 38070059) 0503185 (bank code 37010050) 168927-501 Fax: (0228) 659093 Patvocat·

with a great deal of mechanical effort, several consecutive processing steps are also required.

The invention is based on the object of manufacturing such rotors for electrical machines and devices, in particular stepper motors, in a significantly simpler, more precise and cleaner manner.

This object is achieved according to the invention in that the sleeve enclosing the inner parts of the rotor has been pressed onto these parts by means of radial pressure.

This radial pressing pressure can, under certain circumstances, be applied mechanically.

However, according to a further feature of the invention, it is particularly advantageous both in terms of the tools used and in terms of manufacturing precision and environmental friendliness if the radial pressing pressure is generated by the magnetic field of a high-current conductor surrounding the rotor according to the unpublished German patent application P 44 36 615.9. In this method for the magnetic deformation of metal parts with high magnetic pulses, a high-current loop is used to hold tubular metal parts to be deformed, which have a larger outer diameter before deformation and, after deformation by a high magnetic pulse, firmly enclose the inner parts of the rotor without additional means.

This process enables contact-free deformation of workpieces, especially those in the form of cylinders, which are connected to one another. The connection is highly pressure-resistant. Contact-free deformation can be used especially for

Pipes and rings made of mechanically deformable metallic materials, such as copper, aluminum and light metal alloys. The advantages of contactless forming are obvious. The parts to be joined are assembled without the addition of soldering aids, adhesives or the application of weld metal. Neither toxic fumes nor outgassing are produced during the manufacturing process. The process is therefore extremely environmentally friendly. The forming process does not damage the coatings of the parts to be formed. Overall, this leads to gentle product treatment and an environmentally friendly process. This type of forming is therefore particularly suitable for all areas of assembly technology where several individual parts are joined together and mounted in an aluminum cylinder, for example. The contactless forming makes it easy to precisely assemble the individual parts of a magnetic rotor of electrical machines and devices. Work steps such as gluing, soldering and flanging can be eliminated. Furthermore, it is possible to seal a large number of individual parts without contact, to apply flanges and to produce metal deformations according to the desired shapes without contact in a single operation. No soldering, welding, gluing or screwing is required, and yet different parts and materials can be combined to create a particularly high-quality finished product.

The invention has the particular additional advantage that the individual parts of the rotor only have to be loosely inserted into the surrounding sleeve or the metal tube, whereby the sleeve or the tube automatically forms a protection for the individual parts during deformation and, for example, effectively prevents brittle parts of permanent magnet bodies from chipping off. This is particularly advantageous if the

Many magnetic parts are enclosed in the sleeve or metal tube, resulting in high precision of such rotors.

For the manufacture of the rotors, it can also be particularly advantageous if the inner parts of the rotor are enclosed by a radially pressed-on metal tube, whereby the ends of the sleeve or the metal tube protrude beyond the inner parts and can thus be flanged towards the axis of the rotor in a single operation in order to fix the individual parts of the rotor precisely against each other not only radially, but also in the axial direction.

Preferred further features of various embodiments of such rotors are characterized in claims 5 to 7.

Preferred embodiments of the invention are shown schematically in the drawing.

Fig. 1 is a partially cutaway perspective side view of the individual parts of a rotor for electrical machines and devices with a metal tube surrounding them before the deformation of the metal tube,

Fig. 2 is a plan view of Fig. 1,

Fig. 3 is a perspective side view of the rotor of Fig. 1 and 2 after deformation of the metal tube,

Fig. 4 is a plan view of Fig. 3,

Fig. 5 is a plan view of an embodiment of such a rotor modified from Figs. 1 to 4,

Fig. 6 shows a further modified embodiment of a rotor with circular segment-shaped permanent magnet bodies and

Fig. 7 shows another modified embodiment of such a rotor.

Fig. 1 to 7 show various embodiments of rotors 1 for electrical machines and devices, in particular stepper motors, each of which consists of an iron core 2, several surrounding permanent magnets 3, optionally non-magnetic filler pieces 4 arranged between them and an outer ring-shaped sleeve 5 made of an electrically conductive material (metal) that encloses these individual parts. The

Sleeve 5 has been pressed onto the inner parts 2, 3 of the rotor 1 by radial pressure.

The radial pressing pressure was advantageously generated by the magnetic field of a high-current conductor surrounding the rotor according to German patent application P 44 36 615.9.

In all the embodiments shown, the inner parts 2, 3 of the rotor 1 are enclosed by a radially pressed-on metal tube 5. The ends of the sleeve or the metal tube 5 can also protrude beyond the inner parts 2, 3 and be flanged towards the axis of the rotor 1 without this being specifically shown in the drawing.

In the two embodiments of Fig. 1 to 4 and Fig. 5, the permanent magnets 3 surrounding the iron core 2 and the non-magnetic filler pieces 4 arranged between them are designed in the shape of a circular sector and lie flat against one another. They are enclosed by the sleeve or metal tube 5 at a constant radial distance from the iron core 2. The permanent magnets 3 can also have a cuboid shape. The shrink sleeve then lies firmly on the outer walls of the permanent magnets 3 arranged in a ring around the iron core 2 and forms a polygonal shell corresponding to the number of magnets.

In the two other embodiments of Fig. 6 and 7, the iron core 2 has a polygonal or square cross-section, while the permanent magnets 3 surrounding the iron core 2 have a circular segment-shaped cross-section. In the embodiment of Fig. 6, the permanent magnets 3 surrounding the iron core 2 lie closely against one another in the area of the longitudinal edges of the iron core 2 with their radially running beveled longitudinal edges 6.

In the embodiment of Fig. 7, the iron core 2 has a polygonal or square cross-section, and the permanent magnets 3 surrounding the iron core have a circular segment-shaped cross-section with rounded longitudinal edges 7. The permanent magnets are also arranged at such a distance from one another in the area of the longitudinal edges of the iron core that the sleeve or metal tube 5 surrounding the permanent magnets 3 has longitudinal grooves 8 drawn inward in the direction of the longitudinal edges of the iron core 2. As a result, the permanent magnet bodies 3 are also fixed very precisely to the four outer surfaces of the iron core 2 and immovably at a completely uniform radial distance from the axis of rotation of the rotor 1.

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• ATTORNEY FILE ·*·
· 2 894/95

List of reference symbols

1 rotor 2 Iron core 3 Permanent magnets 4 Filler pieces 5 Sleeve, metal tube 6 Longitudinal edges 7 Longitudinal edges &dgr; Longitudinal grooves

Claims (7)

Applicant: 28 June 1995 MAGNET-PHYSIK Dr. Steingroever GmbH Emil-Hoffmann-Str. 3 50996 Cologne VNR: 108 545 ATTORNEY FILE 2 894/95 Protection claims 1. Rotor for electrical machines and devices, in particular stepper motors, which consists of an iron core, permanent magnets surrounding it, optionally non-magnetic filler pieces arranged between them and an outer annular sleeve made of an electrically conductive material (metal) surrounding the latter, characterized in that the sleeve surrounding the inner parts (2, 3) of the rotor (1) has been pressed onto these parts by radial pressure. 2. Rotor according to claim 1, characterized
that the radial pressing pressure was generated by the magnetic field of a high-current conductor surrounding the rotor (1). • · · ·— 1TT · — · ···· • · · t « · *iiJ it 4»· · 3. Rotor according to claim 1 or 2, characterized in that the inner parts of the rotor (1) are enclosed by a radially pressed-on metal tube (5). 4. Rotor according to one of claims 1 to 3, characterized in that the ends of the sleeve or the metal tube (5) protrude beyond the inner parts (2, 3) and are flanged towards the axis of the rotor (1). 5. Rotor according to one of claims 1 to 4 with a cylindrical iron core, characterized in that the permanent magnets (3) surrounding the iron core (2) and the non-magnetic filler pieces (4) arranged between them are designed in the shape of a circular sector and lie closely against one another and are enclosed by the sleeve or the metal tube (5) at a constant radial distance from the iron core (2). 6. Rotor according to one of claims 1 to 4, characterized in that the iron core (2) has a polygonal cross-section, and that the permanent magnets (3) surrounding the iron core (2) have a circular segment-shaped cross-section and lie flat against one another on the longitudinal edges of the iron core (2) with their radially extending beveled longitudinal edges (6). 7. Rotor according to one of claims 1 to 4, characterized in that the iron core (2) has a polygonal cross-section and that the permanent magnets (3) surrounding the iron core (2) have a circular segment-shaped cross-section with rounded longitudinal edges »■· ten »·# (8) and are arranged at a distance from one another in the region of the longitudinal edges of the iron core (2) such that the sleeve or the metal tube (5) enclosing the permanent magnets (3) has longitudinal grooves (8) drawn inwards in the direction of the longitudinal edges of the iron core (2).