EP2707941A1

EP2707941A1 - Magnetic gear mechanism with coils around permanently excited magnet poles

Info

Publication number: EP2707941A1
Application number: EP11749843.6A
Authority: EP
Inventors: Dieter Munz; Markus Reinhard
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2011-08-31
Filing date: 2011-08-31
Publication date: 2014-03-19
Also published as: US20140225467A1; CN103765742A; RU2014112041A; WO2013029676A1; BR112014003995A2

Abstract

The dynamics of a magnetic gear mechanism are intended to be improved. For this purpose, a magnetic gear mechanism with a stator, a first rotor, which has permanently excited magnet poles (2, 3), and a second rotor, which likewise has permanently excited magnet poles, is proposed. The rotors are magnetically coupled to the stator. In each case one coil (5) is wound around each of the magnet poles (2, 3) of the first rotor. The coils (5) of the magnet poles (2, 3) are connected in series. The series circuit of the coils (5) can be supplied direct current in order to alter the magnetic flux through the magnet poles (2, 3) in comparison with the de-energized state.

Description

description

Magnetic gear with coils around permanent magnet ^¬ magnet

The present invention relates to a magnetic gear with a stator, a first rotor having permanent magnet magnetic poles, and a second rotor, which also has permanent magnet magnetic poles, wherein the rotor are magnetically coupled to the stator. Moreover, the present invention relates to a method of operating a magnetic transmission constructed as above.

For some time, so-called "magnetic gear" be ^¬ known. These consist of at least two runners (input and output side) and a stand. The runners carry permanent ^¬ magnets of different poles. The number of poles for each runner results from a rule of interpretation. The magnets are applied to a magnetic return.

The driven rotor generates a rotating magnetic field which rotates in depen ^¬ dependence of the number of poles in synchronism with the rotor in the air gap (between the first rotor and stator). The stand is partly made of soft magnetic materials. There are mostly of iron sheet metal or soft magnetic ^¬ specific compound materials (soft magnetic composites) or soft ferrite. Object of the stand is such that the field rotates the alternating magnetic field from the drive side in a suitable manner to demodulate mo ^¬, on the output side (in the second air gap between the stator and rotor flange on output) at a different frequency. Thus, a change in the speed (reduction) can be achieved when the drive-side rotor coupled with the number of poles occurring.

In previously known implementations, the two runners, regardless of whether axial or radial flux guidance (disc-like or tubular design of the rotor) is present, permanent magnets (preferably made of NdFeB) of different number of poles. The magic Neten of the driven rotor (a disc in axial An ^¬ order and a tube in a radial arrangement) generate a rotating magnetic field, which is modulated by the flux guiding teeth in the fixed stator (also a disc or a tube) and then on the output side with the Field of magnets on the second runner (turn disk or tube) is coupled. By choosing the number of magnets, the gear ratio is set. Both Un ^¬ ter and a translation is possible. The strength of the magnetic field defines the maximum possible torque. If this torque is exceeded, the gear falls out of step. Decreases the load torque below the critical Drehmo ^¬ ment, the transmission is synchronized again. It is not possible to control the behavior in the out-of-kick case and in the synchronization. This would be desirable.

The object of the present invention is thus to be able to variably configure the behavior of a magnetic transmission in the out-of-step case and / or during synchronization.

According to the invention this object is achieved having with a magneti ^¬ ULTRASONIC transmission with a stator, a first rotor, the permanent-magnet magnetic poles, and having a second rotor, the permanent-magnet magnetic poles, wherein the Läu ^¬ fer are magnetically coupled to the stator, and wherein around each of the magnetic poles of the first rotor per a coil is threaded ^¬ oped, the coils of the magnetic poles are switched in accordance with a ers ^¬ th series circuit in series, and the first series circuit of the coil with direct current can be supplied to the magnetic flux by the magnetic poles of the first Runner compared to the de-energized state change.

Moreover, according to the invention there is provided a method of operating a magnetic gear having a stator, a first rotor having permanent magnet magnetic poles, and a second rotor having permanent magnet magnetic poles, the rotors having the stator are magnetically coupled, by providing each a coil around each of the magnetic poles of the first rotor, wherein the coils of the magnetic poles are connected in series according to a first series circuit, and supplying the first series ^{scarf ¬} tion of the coils with direct current to the magnetic flux through the magnetic poles to change the first runner with respect to the de-energized state.

In an advantageous manner, so each wound a coil around each magnetic pole of the f th ^¬ rotor, and the coils who ^¬ / are connected to a winding in series. Thus, all coils of the first rotor can be supplied with a direct current, with which the magnetic flux can be changed by the magnetic poles as needed. Thus, it can be weakened in ^¬ example in an out-of-step case and strengthened to synchronize.

Preferably, a coil is wound around each of the magnetic poles of the second rotor, the coils of the magnetic poles are connected in series according to a second series connection for a second winding, and the second series ^¬ circuit of the coil can be supplied with DC to the magnetic flux through to change the magnetic poles of the second rotor with respect to the de-energized state. Thus, not only in the first runner, but also in the second runner of the transmission, the critical torque can be changed.

Advantageously, the winding direction of each coil depends on the direction of magnetization of the permanent magnets of the respective magnetic pole. Thus, the magnetic fluxes all magnetic poles can be strengthened or weakened by one and the same DC.

In particular, adjacent magnetic poles may be oppositely magnetized by permanent magnets ^¬ and therefore have coils with mutually opposite winding direction. Thus, the circumference of the runner or the runner change Magnetizations of the magnetic poles from one magnetic pole to the other ^¬ ren regularly.

In particular, each of the magnetic poles should have a soft magnetic core ^¬ rule. This has the advantage that the coils do not have to be wound around the permanent magnets that have the relative Per ^¬ meabilitätszahl air about.

Rather, the coils are then wound around a soft magnetic core, so that a smaller amount of current necessary to achieve a desired magneti ^¬ rule flow.

The magnetic poles of the first rotor can be arranged segment-like on a soft magnetic disk, wherein grooves are formed in the pole gaps, in which the coils are inserted. Due to this special design, the coils receive a soft magnetic core.

In an advantageous embodiment, the magnetic transmission has a temperature sensor that outputs a temperature signal, and a first control device for controlling the direct current through coils in response to the temperature signal. This has the advantage that a weakening of the field due to a temperature increase can be compensated.

In addition, the magnetic gear may have passed through the coils in response to the overload signal an overload ^¬ sensor which outputs an overload signal, and a second STEU ^¬ ereinrichtung for controlling the DC current. This has the advantage that the consequences of the overload can be eliminated more quickly (shaking or asynchronism).

Furthermore, the magnetic transmission may comprise a third STEU ^¬ ereinrichtung with which the power is so controllable by the coil, that during a predetermined start-up phase of the respective rotor, the magnetic flux is strengthened by the magnetic poles relative to the energized state. It can hereby be ensured that the magnetic Ge ^¬ gear at start-up is synchronized faster.

The present invention will be explained in more detail with reference to the accompanying drawing, which schematically illustrates a disc-shaped rotor of a magnetic transmission in plan view.

The embodiments described in more detail below represent preferred embodiments of the present invention.

A magnetic gear of the type mentioned has two rotor, which are provided with permanent magnets of a certain magnetic material. Since the maximum transmissible rotating ^¬ moment on the field strength of the field and therefore mainly depends on the residual induction B _R of the magnetic material used, the "tipping moment" may be after the production of Ge ^¬ drive according to the prior art does not change ^¬ the. With However, this is to be made possible by the magnetic transmission according to the invention or the method according to the invention for operating such a transmission.

Magnetic transmissions are typically realized with tubular runners or disc-shaped runners. The example of the figure shows a plan view of a slices ^¬ shaped rotor. In the present case, it is a 12-pole runner. Each pole is segmented ^{ausgebil ¬} det. A pole pitch 1 thus corresponds to a segment of the disc. In the right part of the figure symbolically two oppositely directed magnetic poles 2 and 3 are shown. One magnetic pole 2 is magnetized into the plane of the drawing, ie its direction of magnetization is perpendicular to the plane of the drawing and points into it. In contrast, the other magnetic pole 3 is magnetized out of the plane of the drawing. Its magnetization direction points entspre ^¬ accordingly out of the plane. Also in the other pole pitches 1 magnetic poles are included. Your magnetization direction changes in the circumferential direction from pole pitch to pole pitch. Each of the magnetic poles 2, 3 is energized by permanent magnets. In order to avoid a magnetic short circuit, pole gaps 4 between the magnetic poles 2, 3 must be provided. Therefore, the magnets of the magnetic poles are narrower than the pole pitch 1. These pole gaps 4 take here the winding or coils 5. To fix the coils, the pole gaps 4 can be cast after inserting the coils. This also reduces the air vortex losses.

To strengthen the magnetic field, the coil should be wound around a ferromagnetic component. This is at a conclusion that the disc represents as a carrier made of e.g.

Soft ferrite or SMC particularly easy. Along the boundaries of the pole pitch for this purpose namely the disc star-sawed or milled. This results in small columns of ferrite / SMC, around which the winding or coil 5 can be laid.

The coils can be easy to make cylindrical coils, which are brought into the shape of the contour of the magnets. Also conceivable are windings on a (flexible) conductor track.

Thus, a winding or coil 5 is provided around each permanently excited magnetic pole 2, 3. Since adjacent poles are magnetized oppositely, the winding sense must be changed by je ^¬ the magnet. This allows the coils to be connected together in a series connection and all fed with the same direct current. As an alternative, all magnetic poles could be provided with coils of the same winding sense and the coils of adjacent magnetic poles are then energized in the opposite direction. The latter requires a more complex interconnection.

By feeding a direct current into the winding or the series-connected coils 5, the fields are al- magnets either strengthened or weakened. The strength of the magnetic field of the coils is dependent on the number of turns, the magnitude of the current and a possible strengthening of the field by soft magnetic core materials.

In the example of the figure, a direct current I _{DC is} fed into the upper terminal of the coil 5 of the magnetic pole 2, so that it flows out again at the lower terminal. This excites a magnetic field that is directed out of the plane of the drawing. It thus weakens the magnetic field which is excited by the permanent magnets in the direction of the plane of the drawing.

Since the magnetic pole 3, the coil 5 has a coil inner inverted Wick-, the DC current I _DC flowing in the lower connection in the coil and in the upper terminal from their forth ^¬ from. The current thus flows in a clockwise direction, thus exciting a magnetic field which is directed into the plane of the drawing. Thus, it also weakens the magnetic field which is excited by the permanent magnets of the magnetic pole 3, which is directed out of the plane of the drawing.

The current intensity of the DC current supplying the coils 5 is controlled or regulated, for example, by a control device which receives signals from one or more sensors. Such sensors may be, for example, temperature sensors or overload sensors. An overload sensor detects, for example, a shaking of the transmission, which occurs when the transmission "rotates" due to overload, for example, such "spin" can also be registered electrically on the stator.

There are many reasons for changing the magnetic field of the magnetic poles of a magnetic transmission by impressing a direct current. For example, a magnetic Ge ^¬ gear is used in a mill. Be in the mill milled under ^¬ differently hard materials, the breakdown torque of the gear to protect the drive Strange must accordingly be set. To adjust the overturning moment, the direct current is adjusted accordingly.

Another reason for changing the magnetic field in a magnetic transmission may be its heating. Due to the heating of the magnets whose induction is lowered, so that by the heating (losses proportional to the speed) decreases the maxi ^¬ times transmissible torque. This weakening of the field can be compensated by a superimposition of a same-way electrically excited magnetic field.

In addition, a magnetic gearbox can "spin" by overload, producing strong vibrations because the magnetic fields of the rotors are still full, and the magnetic fields are then deliberately weakened by impressing a corresponding current to minimize jarring.

Another reason for changing the magnetic field may be to synchronize the transmission again faster after an out-of-step case. For this purpose, the field can be strengthened for a short time.

Furthermore, not only the Lastmo ^¬ ment, but also the moment of inertia of the runners must be overcome in a run-up. During startup, the magnetic field can then be ^boosted . The magnets must be designed in this case only for the load torque.

The energy for feeding the winding can be transmitted to the rotor through slip rings or inductive transformers. Also conceivable is the use of motors with integrated energy transfer to the runner.

With the invention, the dynamics during startup, out-kicking and re-synchronization over known magnetic transmissions are advantageously improved. This is achieved through the use of an easy-to-manufacture DC Winding achieved. To all poles simultaneously either to strengthen or weaken magnetic ^¬ table (of course, not via the irreversible point addition) are wound, the windings either in opposite directions or the windings are energized in opposite directions.

Reference sign list

pole pitch

magnetic pole

pole gaps

Do the washing up

direct current

Claims

claims

1. Magnetic gear with

- a stand,

- A first rotor, the permanent magnet magnetic poles (2, 3), and

- a second rotor, the permanent-magnet magnetic poles ^¬ has, wherein

- The runners are magnetically coupled to the stator, characterized in that

- a coil (5) is wound around each of the magnetic poles (2, 3) of the first rotor,

- The coils of the magnetic poles are connected in series according to a first Rei ^¬ henschaltung, and

- The first series connection of the coils with DC (I _D c) can be supplied to change the magnetic flux through the magnetic poles of the first rotor with respect to the de-energized state.

2. A magnetic transmission according to claim 1, wherein each wound around a coil of each of the magnetic poles of the second rotor, the coils of the magnetic poles are connected in series according to a second series circuit, and the second series ^¬ circuit of the coils can be supplied with DC to the magnetic flux through the magnetic poles of the second rotor with respect to the de-energized state to change.

3. A magnetic gear according to claim 1 or 2, wherein the winding direction of each coil (5) depends on the direction of magnetization of the permanent magnets of the respective magnetic pole (2, 3).

4. A magnetic transmission according to claim 3, wherein adjacent magnetic poles (2, 3) are magnetized by permanent magnets opposite and therefore have coils (5) with mutually opposite winding direction.

5. Magnetic gear according to one of the preceding claims, wherein each of the magnetic poles (2, 3) has a weichmagne ^¬ tables core.

6. A magnetic transmission according to claim 5, wherein the Magnetpo ^¬ le (2, 3) of the first rotor are arranged in segments on a weichmag ^¬ genetic disc, and in the pole gaps (4) grooves are formed, in which the coils (5) inserted are.

7. A magnetic transmission according to one of the preceding claims, which has a temperature sensor which outputs a temperature signal, and a first control device for controlling the direct current through the coils in dependence on the Tempe ^¬ ratursignal.

8. A magnetic transmission according to one of the preceding claims, comprising an overload sensor which outputs an overload signal, and a second control means for controlling the direct current through the coils in response to the overload signal.

9. A magnetic transmission according to one of the preceding claims, which has a third control device with which the direct current is controlled by the coils, that during a predetermined start-up phase of the respective rotor, the magnetic flux through the magnetic poles (2, 3) relative to the energized state is strengthened.

10. A method of operating a magnetic transmission having a stator, a first rotor, the permanent-magnet magnetic poles, and has a second rotor having per ^¬ manenterregte magnetic poles, said armature being magnetically coupled to the stator,

marked by

- Providing a respective coil (5) around each of the magnetic poles

(2, 3) of the first rotor, wherein the coils of the magnetic poles are connected in series according to a first series circuit, and - Supplying the first series connection of the coils (5) with direct current (IBC) to change the magnetic flux through the Mag ^¬ netpole of the first rotor with respect to the de-energized state.