US3741613A

US3741613A - Electromagnetic levitation guide

Info

Publication number: US3741613A
Application number: US00162365A
Authority: US
Inventors: C Pfaler
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 1970-07-18
Filing date: 1971-07-14
Publication date: 1973-06-26
Anticipated expiration: 1990-06-26
Also published as: FR2101787A5; DE2035840A1; GB1356290A; JPS5148329B1; DE2035840B2

Abstract

An electromagnetic levitation guide for a movable body has at least one direct-current magnet to hold the body in levitation. A ferromagnetic rail is arranged along the travel path of the body at a constant spacing from the magnet, whereby the rail constitutes the armature return for the flux developed by the magnet. The magnet has a core having pole faces and the armature return also has pole faces; these pole faces are long and narrow and extend longitudinally in the direction of the travel path.

Description

5 1 l 3 SR P11 8502 12R 7 g7 t11s13 D United States Patent [1 1 [111 3,741,613 Pfaler June 26, 1973 [54] ELECTROMAGNETIC LEVITATION GUIDE 3,594,622 7/1971 Inagaki 104/148 LM 3,5 5, 7 197 104148 LM [75] lnvenw" cal'l'Efic male" Mumch Germany 3,4372%; lO/196t 1 310/13 73 Assignee; Siemens Akfiengeseuschafi Berlin. 3,470,828 10/1969 Powell 104/148 LM Germany 3,225,228 12/1965 Roshala 104/148 LM 3,462,666 8/1969 Martinek 310/17 [22] Filed: July 14, 1971 Primary Examiner-R. Skudy [21] Appl' 162365 Attorney-Curt M. Avery, Herbert L. Lerner et a1.

[] Foreign Application Priority Data [57] ABSTRACT July 18, 1970 Germany P 20 840.1 An electromagnetic levitation guide for a movable body has at least one direct-current magnet to hold the [52] US. Cl 308/10, 104/148 LM, 310/13 body in levitation. A ferromagnetic rail is arranged [51] Int. Cl. F16c 39/06 along the travel path of the body at a constant spacing [58] Field of Search 308/ 10; 310/12, 13, from the magnet, whereby the rail constitutes the arma- 310/17; 73/503; 104/148, 148 LM, 148 MS, ture return for the flux developed by the magnet. The 148 SS magnet has a core having pole faces and the armature return also has pole faces; these pole faces are long and [56] References Cited narrow and extend longitudinally in the direction of the UNITED STATES PATENTS travel p 3,233,559 2/1966 Smith 104/148 LM 6 Claims, 3 Drawing Figures PAIENIEDJUHZS 1925 3.741 613 sum 1 0F 2 ELECTROMAGNETIC LEVITATION GUIDE My invention relates to an electromagnetic floating or levitation guide for movable bodies, especially for a fast vehicle which is held in levitation with at least one directcurrent magnet. A ferromagnetic rail is mounted along the travel path of the vehicle and is arranged at a constant separation with respect to the magnet and serves as an armature return.

For magnetic levitation, vehicles can be equipped with a plurality of direct-current magnets which are placed one next to the other in long bands and work together with ferromagnetic rails arranged on the path structure. In order to secure the guidance of the vehicle in all spacial directions, there are in addition to bans of carrier magnets, bands of guiding magnets arranged on the vehicle and lateral guiding rails arranged along the path of movement in order to cancel the gravity forces. In this way, centrifugal forces and lateral forces are balanced out on curved portions of the travel path and in straight portions thereof.

With a rapid movement of bodies held in levitation electromagnetically, there occur braking forces because of eddy currents induced in the rails. These losses can be held small if the rails are put together of thin, low loss sheets.

Rails can be assembled from stacked cast iron plates having a low specific electrical conductivity and a low magnetic permiability in order to hold the formation of eddy currents small.

Accordingly, it is an object of my invention to reduce the braking forces without the application of costly laminations or ferromagnetic material having a low conductivity such as, for example, ferrite.

According to a feature of the invention, in an electromagnetic levitation guide of the above-mentioned type, I configure the pole faces of the core and of the return armature body of the direct-current magnet so as to be narrow and extending lengthwise in the direction of movement. In this way a substantial reduction of the braking forces caused by eddy currents is achieved alone through the configuration of the direct-current magnet. By using a long, narrow direct-current magnet, eddies of the electric field occur only at the ends with a uniform movement, so that with respect to the known configurations, eddy currents are induced only in the regions near the ends of the magnetic arrangement, whereby the braking forces become independent of the length of the pole faces of the direct-current magnet. Although the carrying force is reduced linearly with a reduction in the width of the pole faces, the braking forces, however, are reduced quadradically with a reduction in the width of the pole faces.

The invention will now be described with reference to the drawing, wherein:

FIG. 1 illustrates a perspective view of an electromagnetic levitation guide equipped with a directcurrent magnet configured as required by the invention; and,

FIG. 2a and FIG. 2b illustrate an alternate embodiment of the direct-current magnet in section and plan view, respectively.

As a levitation guide, there is at least one carrying magnet arranged on vehicle 1 which is configured as a direct-current magnet 2. A ferromagnetic rail 3 is disposed at a constant spacing from the magnet 2 along the travel path as an armature return member. The direct-current magnet 2 has coils 6 which are supplied from a generator 10 via a rectifier apparatus 11. A generator 10 is arranged on the vehicle 1 and is driven from a drive machine 12. By means of the control equipment 7, the current in the coil 6 is regulated such that a predetermined spacing from the rail is maintained. For this purpose, there is provided a feeler or sensor 8 arranged with respect to the direct-current magnet 2 which, in dependence upon the spacing between magnet 2 and rail 3, delivers different control voltages at its output terminals for regulating the spacing. The feeler 8 is, for example, a magnetic-field dependent resistance, especially a galvanomagnetic device such as a Hall generator.

The magnetic power fiux flows transverse to the travel direction s in the direct-current magnet 2. According to the levitation guide of the invention, the pole faces 5 of both the core 4 and rail 3 of the directcurrent magnet are configured to be narrow and extend with a long surface in the direction of movement s. The length l of the pole faces is substantially larger, for example, 50 times larger than width b of the pole faces of the rail 3. According to a preferred embodiment, the pole faces are 600 times larger than the width b. The length l of the magnets is then 30 meters and the width b is 2.5 cm. For an air gap 8 1 cm, it is sufficient if the rail has a width of 10 cm. With an induction of 0.5 Tesla and of a velocity of 400 km per hour, the braking force amounts to only 2 percent of the carrying force.

Preferably the width b of the core 4, the rail 3 and the pole faces 5 are dimensioned at least to be approximately the same.

As illustrated in FIG. I, it is advantageous with a U- shaped configuration of the core 4 of the direct-current magnet 2, to also dimension the rail 3 as a U-shaped member arranged at least to approximate a mirror image of the direct-current magnet. With the application of the direct-current magnet as a carrying magnet, there is obtained a stabilization action against lateral movements at the same time.

According to one embodiment of the invention, a direct current magnet is provided with several individual coils 6 placed serially one next to the other in the direction of vehicle movement s as illustrated in FIGS. 2a and 2b. In this configuration, the core 4 is provided with closed slots 13 on both of its arms in which the

individual coils

6a, 6b are placed. Through the division of the longitudinal extending magnets, the inductivity of the coil 6 is reduced 'which, for control, is very advantageous. Preferably, the slots 13 are closed by slot closing means such as slot wedges 13a or the like. And in this way, the mounting of the coils is facilitated.

According to another embodiment, the directcurrent magnet 2 is put together from

several component cores

4a, 4b equipped with

individual coil

6a, 6b,

so that the separating interface 14 in the pole faces 5 do not form a functional air gap. In this way, the

component cores

4a, 4b, serially placed one next to the other, function as a practical matter as a single directcurrent magnet. Non-uniformities are, according to a further feature of the invention, cancelled by ancillary coils 15 arranged over the coil portions, the latter being in the slots 13.

While the invention has been described by means of specific examples and in a specific embodiment, I do not wish to be limited thereto, for obvious modifications will occur to those skilled in the art without departing from the essential features of the invention and within the scope of the claims annexed hereto.

I claim:

1. Electromagnetic levitation guide for a movable body, comprising at least one direct-current magnet to hold the body in levitation, a ferromagnetic rail arranged along the travel path of said body at a constant spacing from said magnet, whereby said rail constitutes the armature return for the flux developed by said magnet, said magnet comprising a core having pole faces and said armature returns having pole faces, said pole faces being elongated and extending longitudinally in the direction of said travel path, the length of each of said pole faces being at least fifty times its width.

2. Electromagnetic levitation guide according to claim 1, said core being U-shaped, and said armature return being profiled to have a U shape and arranged to be at least approximately the mirror image of said magnet.

3. Electromagnetic levitation guide for a movable body, comprising at least one direct-current magnet to hold the body in levitation, a ferromagnetic rail arranged along the travel path of said body at a constant spacing from said magnet, whereby said rail constitutes the armature return for the flux developed by said magnet, said magnet comprising a core having pole faces and said armature returns having pole faces, said pole faces being elongated and extending longitudinally in the direction of the travel path, said core having slot means, said magnet comprising a plurality of coils aligned serially next to each other in said slot means, and closing means for closing said slot means.

4. Electromagnetic levitation guide according to claim 3, said magnet comprising a plurality of core components having respective individual coils, said core components having respective sets of pole faces, said components being placed together so that the respective interfaces between mutually adjacent components do not constitute functioning air gaps.

5. Electromagnetic levitation guide according to claim 4, said magnet comprising ancillary coil means arranged over said coils.

6. Electromagnetic levitation guide for a movable body, comprising at least one direct-current magnet to hold the body in levitation, a ferromagnetic rail arranged along the travel path of said body at a constant spacing from said magnet, whereby said rail constitutes the armature return for the flux developed by said magnet, said magnet comprising a core having pole faces and said armature returns having pole faces, said pole faces being elongated and extending longitudinally in the direction of said travel path, the respective widths of said core, of said armature return and of said pole faces being dimensioned to be at least approximately the same.