DE2139009A1 - Magnetic coupling with two coaxial rotors - Google Patents

Description

Dipl.-Ing. EE Hnkener
Dipl-Ing. W. Ernesti SociSte anonyme dite ι CEPlLAC

Patent attorneys

463 Bochum Paris / France

HeinriA-König-Strasse 12 ■ '

Telephone 415 SO, 4 23 27 Telegram address: Radtpatent Bodram

71 155 WE / US

Magnetic coupling with two coaxial rotors

The invention relates to a magnetic coupling with two coaxial Rotors that are mechanically rotatable independently of each other and on the one hand on a driving as well on the other hand, are mounted on a driven shaft, a Botor having a multi-pole inductor and the other Botor is designed as an inducible part, which is an element made of ferromagnetic material permanent magnetic properties with high coercive field strength contains

To the various magnetic couplings for drive or Braking purposes in which the torque is only generated by the force magnetic field is generated, also include clutches based on the hysteresis of a ferromagnetic body. In the latter case, the magnetic flux generated by an inductor is passed into a second body from a magnetically hard material, i.e. a body with permanent magnetic properties. These Clutches run at synchronous speed as long as a certain torque is not exceeded. When increasing If the torque exceeds this specific value, there is a slip between the two motors and that too The transmitted torque remains essentially constant even with a variable slip.

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The object of the invention is to provide a magnetic coupling, which is suitable for both drive and braking purposes, to be trained so that in a certain Operating range the torque is transmitted without slip, but in a subsequent range with increasing Slip a rapidly increasing torque is generated as a function of this slip;

According to the invention, this task is achieved with a magnetic coupling of the type mentioned above in that the inducible rope also has an element made of electrical contains a highly conductive material that is associated with the ferromagnetic Material is in contact with the existing element.

In a further embodiment of the invention, the element consists of a material of good electrical conductivity or aluminum Copper. This element is according to the further invention arranged to face the inductor.

In a further embodiment of the invention, goal is seen, that the inductor is arranged on the driven and the inducible part on the drivable Botor or vice versa is.

In a first embodiment, after the other Invention between the inductor and the inducible part in a plane perpendicular to the axis of the Hotoren an air gap provided and made of electrically highly conductive material element designed as a washer.

In a second embodiment, a further development of the invention lies between the inductor and the inducible Part of a cylindrical air gap, the element consisting of a material that is a good electrical conductor has the shape of a cylindrical tubular piece has.

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The. Use of a trained according to the invention Magnetic coupling offers, among other things, the advantage that a powered machine or the like operated by. a motor normally operated at constant speed is momentarily a higher torque can be delivered, although a slight speed reduction occurs until the normal speed has been set again, but the drive motor is protected against overloads ' is.

Thanks to its special properties, a magnetic coupling is suitable according to the invention particularly advantageous for driving a rotary element in which the torque as Function of the speed increases, as is the case, for example, with a fan for cooling a thermal Motor is the case. With such a drive works the magnetic coupling according to the invention synchronously up to a predetermined speed like a hysteresis coupling, but transmits a torque that increases with increasing engine speed after this speed is exceeded, so that a corresponding increase in the cooling effect is achieved.

Embodiments of the invention are shown in the drawing and are explained in more detail below. It demonstrate:

Figure 1 shows a first embodiment of a magnetic coupling in an axial section,

FIG. 2 shows a section of a rotor in a front view ,

Figure 3 is a graphical representation of the transmitted Torque of the clutch as a function of the slip between the two rotors,

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_ 4 -

Figure 4 is a graphical representation of the dependence of Speed of the driven rotor from the speed of the driving Eotor and

Figure 5 shows a further embodiment of a magnetic coupling in a cross section.

In the embodiment shown in FIGS. 1 and 2, a bot or IL is at the end of a driving shaft 1 fixed in the farm of a disc 2. This rotor is preferably designed as a cast body and consists of one

ΊΟ aluminum alloy. It is attached to shaft 1 by means of a washer 3 "and a nut 4-, which is screwed onto a threaded end of the shaft 1. The disc 2 is against a ball bearing with two rows of Balls pressed on a corresponding paragraph of the

Ί5 shaft 1 is seated and rests against a ring shoulder 6. On the On the outside of the disk 2 there are cooling fins 7 (FIG. 2). The disc 2 contains a recess on the inside 8 in the form of an annular groove in which a ring 9 made of ferromagnetic Material with the properties of a permanent magnet, i.e. with a relatively high Eoerzitivf eid strength, is attached, namely by an adhesive or a notch connection or by means of screws or rivets of the other appropriate means.

The ring 9 can be made of an alloy of iron and chromium, cobalt or tungsten or other alloy components of the AlNiGo group exist. The magnetic properties of the ring 9 are chosen so that the largest possible Hysteresis cycle is run through at every pole change.

A ring is also OK on the inside of the disk 2 made of electrically conductive material attached, which covers the recess 8 and at the edges opposite this survives. The ring 10 can by a notch connection,

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by. Glue or through. Rivets or very staves attached be. It is preferably made of copper or aluminum.

The outer Hing of the ball bearing 5 is non-rotatable with a Botor Ep connected, which consists of an Ead 11 with a hub, a rim 13 and Eadspeichen 14 consists. Between the The hub and the rim is a single disk 15 made of mild steel used to complete the magnetic circuit of the eotor Ep. This magnetic circle also includes a permanent magnet inductor 16 in the form one with alternating north and south poles, which lie on the flat surface that the hung 10 faces. The permanent magnet inductor 16 preferably consists of directional ferrite magnets with, for example eight poles. Instead of a permanent magnet, however, an electromagnet can also be used.

The ball bearing 5 serves at the same time for radial guidance and as an axial stop, it being arranged so that no direct mechanical contact between the driving eotor B _- . and the driven eotor Ep so that the eotor Eg is driven only by the magnetic forces.

A driven part DE is connected to the Botor E ₂ , for example an impeller of a fan which is fastened to the rim by means of screws 21.

During operation of the magnetic coupling, the input 9 consisting of a ferromagnetic material is magnetized by the permanent magnet inductor 16 via the air gap between the two fiotoren B ^ and E ₂ and via the input. Up to a predetermined. Speed, the two motors rotate synchronously, ie the arrangement corresponds to an Eiagnetisciiön Sgmchronkuppliing, dis

2 0 9 8 0 8 / 13S p

Torque 0 _Q depending on the design and dimensions of the essential components. As long as there is no slip between the two rotors, the Hing 10 behaves like part of the air gap. Under these conditions, the magnetic coupling works in the same way as the previously known magnetic couplings.

When the torque is increased above a certain value in the case of a magnetic coupling of the previously known type is, there is a slip between the two Eo tor en, which is made of ferromagnetic material Hing (corresponding to Hing 9 in the embodiment) causes the phenomenon of hysteresis, with the torque is practically constant and independent of the slip speed. Incidentally, the speed changes after they increased from zero to synchronous speed when starting up is practically no longer above this value. The dependence of the torque on the one hand on the relative speed of the driven rotor on the other hand on the speed of the driving Eotor in a known magnetic coupling is represented by the curves X in the diagrams of the figures 3 and 4 shown.

The formation of the magnetic coupling provided according to the invention prevents the torque and the speed from remaining constant above a predetermined value. As soon as the torque rises above the specified value, a relative speed is created between the two rotors, whereby eddy currents are generated in the ring 10, which is made of electrically conductive material, and the higher the relative speed, the stronger the eddy currents. The transmitted torque is thereby increased in the same proportion The course of the übertragenon Dröhaomeafcs Depending on the relative speed ISFC

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in the diagram of Figure 3 by, the curve II of the Time at which a relative speed is present. The dependence of the speed of the driven fiotors of the speed of the driving rotor is through the curve II is reproduced in the diagram of FIG.

In the modified version shown in Figure 5, which has the same functionality as the embodiment according to Figures 1 and 2, the rotors are cylindrical. The driving rotor R ,. consists of an outer support cylinder 22, the induced part in Is formed in the form of an inner sleeve 23 and made of an alloy material with permanent magnetic properties consists. A pipe section 24 made of a material with good electrical conductivity rests on the inner surface of this sleeve. Of the

^ c, rotor R ^ _a is mounted in a cantilevered arrangement on a shaft 25 by suitable means.

The driven rotor Ro _a consists of an inductor with four poles in the form of permanent magnets 26, for example made of TIGOHAL, which are attached to a central piece 27

are that the back connection of the magnetic Represents circle.

Claims

2098Q8 / 1285

Claims (6)

Claims [Αϊ Magnetic coupling with two coaxial rotors, which can be rotated mechanically independently of each other and are attached on the one hand to a driving shaft and on the other hand to a driven shaft, whereby one Botor has a multi-pole inductor and the other rotor is designed as an inducible part, which has an element made of ferromagnetic Contains material with permanent magnetic properties with a high coercive force, characterized in that the inducible part also contains an element (10, 24) made of a highly electrically conductive material which rests against the element (9, 23) made of the ferromagnetic material. 2. Magnetic coupling according to claim 1, characterized in that the element (10, 24) from electrically good conductive material made of aluminum or copper. 3. Magnetic coupling according to claim 1 or 2, characterized in that the element (10, 24) made of electrical the inductor (Rp, Rp) is opposite to the highly conductive material. 4. Magnetic coupling according to one of the preceding claims, characterized in that the inductor (Rp ₁ ^R pa ^ ⁸ ^ ^the driven and the inducible part (R _- ., R _- .) Is arranged on the drivable rotor or vice versa. 5 · Magnetic coupling according to one of Claims 1 to 4, characterized in that there is _{an air gap between the inductor (Rp) and the inducible part (R -} .) In a plane perpendicular to the axis of the rotors, and that the one made of electrically good conductive material Element (10) is designed as an annular disk. 20S8Q8 / 1285 6. Magnetic coupling according to one of claims 1 to 4, characterized in that between the inductor (ß-oa) and the inducible part (E ^) there is a cylindrical air gap and that the element (24) made of electrically conductive material has the shape of a cylindrical drill bit. 209808/1285