DE202010017611U1 - Electromagnetic thrust bearing - Google Patents

Abstract

Electromagnetic axial bearing for a shaft in the manner of a Lorentz force bearing with permanent magnets and a coil surrounding them, which is connected to an energy supply, a large number of individual permanent magnets being arranged next to one another in the bearing area on the circumference of the shaft, characterized in that - the coil ( 2) surrounds the permanent magnets (4) in a fixed, fixed air gap, and - that the coil (2) and the permanent magnets (4) are surrounded by a ferromagnetic yoke (1, 3).

Description

The invention relates to an electromagnetic thrust bearing for a shaft in the manner of a Lorentz force bearing with permanent magnets and a surrounding coil, which is connected to a power supply, wherein in the storage area at the periphery of the shaft a plurality of individual permanent magnets are arranged side by side.

Electromagnetic thrust bearings for rotatably mounted shafts serve to axially fix the shaft or to position it within certain limits in the axial direction. On the shaft then loads to be carried, z. As gripping devices, other bearings, o. The like. Are attached, or process forces are supported.

In the prior art, a variety of practical embodiments of such electromagnetic bearings has become known. Thus, in the case of a standard design, the shaft is provided with a radially protruding disk at the bearing point, which is fixed in a floating manner on both sides, ie on the circumference, by fixed electromagnets between them. To form the required magnetic field with a sufficient field strength, each electromagnet is provided with a yoke. An example of such a thrust bearing goes out of the DE 695 05 526 T2 out.

The disadvantage of such a thrust bearing can be seen in the fact that it is inherently unstable, requires a position control to compensate for this instability and must be constantly supplied with energy. Other disadvantages are that the disassembly is extremely difficult and the radially projecting disc limits the maximum speed of the shaft due to their maximum allowable strength. However, such a thrust bearing with small air gaps, a few 1/10 mm, a high load capacity.

In a variant of such a thrust bearing, a permanent magnet and an electromagnet in the form of a hybrid bearing are combined. A common yoke encloses the radially projecting disc, so that it is fixed axially and radially as a result of the forming magnetic forces.

Such a thrust bearing shows the same advantages and disadvantages as the thrust bearing described above.

In principle, it is also possible to engage in the shaft at its periphery permanent magnets, which are surrounded by stationary permanent magnets. Such a thrust bearing can be easily disassembled, but it is radially unstable, has a poor damping behavior and has a low speed limit and carrying capacity. However, the axial stability is inherently given even without electronics, position control and power supply.

From the KR 102003076802 A A magnetic radial bearing with reinforced axial guiding force emerges. This is a so-called combined bearing for the transmission of axial and radial forces. For this purpose, a bladed iron core is mounted on the shaft to be supported, which surrounds the shaft ring. For the stator, a bladed iron core is also provided, which surrounds the other iron core and is provided with a winding. This is a very complex construction, which is radially unstable and allows only a passive axial bearing with low stiffness and damping.

Finally, so-called Lorentz force bearings are known, with which, however, only a low to medium capacity at higher speed limit can be realized. Basically, such a bearing consists of permanent magnets, which are embedded in the circumference of a shaft, which are surrounded by a fixed coil. An example of this shows the KR 102005056753 A ,

The invention is based on the object of further developing an electromagnetic thrust bearing of the type of a Lorentz force bearing in such a way that it has a significantly higher force density and carrying capacity with simple production.

The object underlying the invention is achieved in an electromagnetic thrust bearing of the type mentioned above in that a coil surrounding the circumference of the shaft in a predetermined air gap fixedly surrounds, and that the coil and the permanent magnets are surrounded annularly by a ferromagnetic yoke.

The particular advantages of the axial bearing according to the invention can be seen in the fact that this can be very easily assembled and disassembled and that the speed limit moves upwards, since a disc limiting the strength is no longer needed on the circumference of the shaft. In addition, the shaft serving as a rotor can be pulled without dismantling the rotor or the stator, i. H. disassemble very easily.

In particular, it has been shown that a significantly higher load capacity and force density and better axial stability over a standard Lorentz force bearing is achieved.

The good axial stability without negative rigidity results in a simple position control.

Furthermore, over a wide axial range of the air gap constant storage properties allow much coarser mounting tolerances and thus a more cost-effective production.

In continuation of the invention, the permanent magnets may be radially magnetized as rings, arranged with alternating polarity, or designed as ring segments with parallel or axial magnetization.

Particularly high magnetic forces are achieved when the permanent magnets are designed in the form of a Halbach magnet arrangement with circumpolar circumferential polarization.

In a further embodiment of the invention, the ferromagnetic yoke consists of a ring member and laterally adjoining yoke legs which enclose the coil.

The yoke and the yoke legs can be made of laminated material, wherein the sheets are preferably made of the materials SiFe, SiFeCo or SiFeP. Of course, other ferromagnetic materials can also be used in principle.

In a continuation of the invention, the permanent magnets are embedded flush in the circumference of the shaft.

Furthermore, the permanent magnets may be provided for their mechanical fixation with a surrounding bandage, whereby even higher speeds can be realized without any problems. The bandage may consist of a carbon fiber reinforced plastic (CFRP).

In a further continuation of the invention, the coil is wound directly into a coil winding body which surrounds the permanent magnets at a predetermined distance, keeping an air gap free.

The coil can also be wound wildly, which reduces the manufacturing effort.

In the thrust bearing, an axial position sensor can be further integrated, which can be additionally coupled with a position control for the thrust bearing.

In a further embodiment, the position control is coupled with an electronic vibration damping.

In an alternative embodiment, the permanent magnets embedded next to one another in the circumference of the shaft are arranged above an iron yoke in the shaft. This embodiment is used in particular when the shaft consists of a non-magnetic material.

For receiving and compensating for a static load, such as a weight force, it is additionally possible to provide additional permanent magnets on the side of the yoke which are arranged opposite a shaft extension formed on the shaft.

The invention will be explained in more detail with reference to an exemplary embodiment. In the accompanying drawings show:

1 FIG. 2: a schematic axial section of an electromagnetic thrust bearing according to the invention; FIG.

2 : a variant of the thrust bearing after 1 with an additional position sensor;

3 a simplified version without bandage and without iron yoke; and

4 : a variant of the electromagnetic thrust bearing 1 , in which additional permanent magnets for receiving a static load, eg. B. a weight force are provided.

The thrust bearing is located in a component and encloses a rotatable shaft to be fixed 6 , According to the realized by the thrust bearing capacity, the shaft 6 be connected to any assemblies such as a gripper, another bearing, etc. ( 1 ). The wave 6 may be made of a non-magnetic or magnetic material.

The thrust bearing contains a large number of individual permanent magnets 4 , juxtaposed in the circumference of the shaft 6 flush over an iron yoke 9 are admitted. The iron yoke forms the lower layer in a groove in the circumference of the shaft 6 , above that then the permanent magnets 4 are used side by side. This iron yoke 9 is particularly required when the shaft 6 made of a non-magnetic material.

To unintentional release of the permanent magnets 4 from the wave 6 Optionally, a bandage can prevent at higher speeds or accelerations 5 be provided, which are the permanent magnets 4 firmly encloses and projects into the air gap. The bandage 5 can be made of carbon fiber, so a carbon fiber reinforced plastic, whereby the permanent magnets also be securely fixed in this at higher speeds of the shaft

The permanent magnets 4 can be radially magnetized as rings, be designed with alternating polarity, or designed as ring segments with parallel or axial magnetization.

Particularly high magnetic forces are achieved when the permanent magnets 4 are designed in the form of a Halbach magnet arrangement with circumpolar circumferential polarization.

The permanent magnets 4 be from a coil 2 enclosed, between this and the permanent magnets 4 an air gap is kept free. Because the coil 2 alone would not form a sufficient magnetic field is a ferromagnetic yoke 1 provided, which is both the coil 2 , as well as the permanent magnets 4 annularly surrounds, such that the coil 2 in the yoke 1 is embedded.

The ferromagnetic yoke 1 has laterally adjoining yoke legs 3 , which may be made ferromagnetic or laminated, wherein for the sheets, in particular the materials SiFe, SiFeCo or SiFeP come into question. In an alternative embodiment, the sheets may be replaced by powder composite materials (eg iron or iron powder alloys). The sink 2 also becomes between the yoke legs 3 through a coil winding body 7 surrounded, a secure fit of the coil 2 guaranteed.

The coil to be connected via a connection to a power source 2 is on the coil winding body 7 wrapped, the permanent magnets 4 surrounds at the predetermined distance ( 2 ). It does not require the coil 2 to wrap in layers, but this can wild in the coil winding body 7 be wound, thereby reducing the manufacturing cost.

By controlling the coil 2 With positive or negative currents can be achieved corresponding positive or negative bearing forces in the axial coordinate direction.

In the thrust bearing can continue to use a sensor 8th be integrated, which may be additionally coupled with a position control and an electronic vibration damping ( 2 ).

The thrust bearing according to the invention allows a comparatively simple assembly and disassembly and achieves a significantly higher load capacity and force density compared to a standard Lorentz force bearing.

In 3 is a simplified variant of the design of the thrust bearing after 1 without bandage 5 and without iron yoke 9 as well as without sensor 8th shown. All other components are as in 1 represented, arranged. Thus, a more detailed description of this embodiment is unnecessary.

4 finally shows a variant of the electromagnetic thrust bearing 1 , at the additional permanent magnets 10 at the yoke 3 for receiving and compensating a static load, eg. B. a weight, are provided.

In this supplementary version with the additional permanent magnets 10 is a shaft shoulder for the formation of a permanent magnetic flux 12 opposite the permanent magnets 10 required. The permanent magnetic path 11 The magnetic flux density runs here from the (in the diagram) upper Parmanetmagneten 10 in the shaft paragraph 12 the wave 6 and from there by the (according to the drawing) lower permanent magnet 10 in the cheekbone 3 and finally closes again in the upper magnet 10 ,

The particular advantage of this design is the fact that the thrust bearing only stabilize the equilibrium position and must hold the centric position, because the weight force through the permanent magnets 10 is caught. In addition, almost no currents are needed to hold the static force, which makes this design particularly efficient.

It is understood that this alternative with the additional permanent magnets 10 of course also in the versions 2 and 3 can be used analogously.

LIST OF REFERENCE NUMBERS

1

yoke

2

Kitchen sink

3

cheekbones

4

permanent magnets

5

bandage

6

wave

7

Coil bobbin

8th

sensor

9

Iron yoke

10

permanent magnets

11

Path of magnetic flux density

12

shaft shoulder

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 69505526 T2 [0003]
• KR 102003076802 A [0008]
• KR 102005056753 A [0009]

Claims (16)

Electromagnetic axial bearing for a shaft of the type of a Lorentz force bearing with permanent magnets and a surrounding coil, which is connected to a power supply, wherein in the storage area at the periphery of the shaft a plurality of individual permanent magnets are arranged side by side, characterized in that - the coil ( 2 ) the permanent magnets ( 4 ) with a predetermined air gap fixedly surrounds, and - that the coil ( 2 ) and the permanent magnets ( 4 ) of a ferromagnetic yoke ( 1 . 3 ) are surrounded. Electromagnetic thrust bearing according to claim 1, characterized in that the permanent magnets ( 4 ) are radially magnetized as rings arranged with alternating polarity. Electromagnetic thrust bearing according to claim 1, characterized in that the permanent magnets ( 4 ) are designed as ring segments with parallel or axial magnetization. Electromagnetic thrust bearing according to claim 1, characterized in that the permanent magnets ( 4 ) are designed in the form of a Halbach magnet arrangement with circumpolar circumferential polarization. Electromagnetic thrust bearing according to claim 1, characterized in that the ferromagnetic yoke ( 1 ) of a ring part and laterally adjoining yoke legs ( 3 ), which the coil ( 2 ) enclose. Electromagnetic thrust bearing according to claim 1 or 5, characterized in that the yoke ( 1 ) and the yoke legs ( 3 ) are made of powder composite materials. Electromagnetic thrust bearing according to claim 6, characterized in that the yoke ( 1 ) and the jachins ( 3 ) consist of sheets of the materials SiFe, SiFeCo or SiFeP or of powder composite materials. Electromagnetic thrust bearing according to one of claims 1 to 7, characterized in that the permanent magnets ( 4 ) in the circumference of the shaft ( 6 ) are inserted flush. Electromagnetic thrust bearing according to claim 8, characterized in that the permanent magnets ( 4 ) with a surrounding bandage ( 5 ) are provided. Electromagnetic thrust bearing according to one of claims 1 to 9, characterized in that the coil ( 2 ) directly into a coil winding body ( 7 ) is wound, the permanent magnets ( 4 ) surrounds at a predetermined distance. Electromagnetic thrust bearing according to claim 10, characterized in that the coil ( 2 ) is wrapped wildly. Electromagnetic thrust bearing according to one of claims 1 to 11, characterized in that an axial sensor ( 8th ) is integrated. Electromagnetic thrust bearing according to claim 12, characterized in that the sensor ( 8th ) is coupled with a position control for the thrust bearing. Electromagnetic thrust bearing according to claim 13, characterized in that the position control is coupled with an electronic vibration damping. Electromagnetic thrust bearing according to one of claims 1 to 14, characterized in that the side by side in the circumference of the shaft ( 6 ) embedded permanent magnets ( 4 ) over an iron backbone ( 9 ) in the wave ( 6 ) are admitted. Electromagnetic thrust bearing according to one of claims 1 to 15, characterized in that laterally on the yoke ( 3 ) additional permanent magnets ( 10 ) are provided for receiving and compensating a static load, which compared to a shaft shoulder ( 12 ) the wave ( 6 ) are arranged.

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