EP0185955B1 - Process for manufacturing a curved disc-shaped magnet coil, and devices for carrying out this process - Google Patents

Description

The invention relates to a method for producing a disc-shaped, curved magnetic coil, in particular for a system for accelerating and / or storing electrically charged particles such as electrons, the conductors of the coil to be produced having a convexly shaped outer side and a concave-shaped inner side The winding core is thus arranged with a partially negative curvature and then fixed in its corresponding position. The invention further relates to devices for performing this method and uses of such devices.

A corresponding solenoid is z. B. from the publication "Fuji Electric Review", Vol. 19, No. 3, 1973, pages 112 to 118. This coil, which is wound from superconductors, is curved along a circular arc length with a predetermined radius and a predetermined arc (central) angle, so that it has a convex-shaped outer side and a concave-shaped inner side. The magnetic coil, the conductors of which are fixed in their geometrical position by struts wiping these sides, is intended to serve as a lifting magnet for the contactless levitation of a vehicle along a roadway.

Also in particle accelerator systems, storage rings for charged particles such as B. electrons have curved dipole magnets due to their curved particle paths. These magnets can in particular be bent in a semicircular shape (cf., for example, “IEEE Trans. On Nucl. Sci.”, Vol. NS-30, No. 4, August 1983, pages 2531 to 2533). Because of the high field strengths required, superconducting windings are preferably provided for this purpose (see, for example, also “Technical Report of ISSP” - The Institute for Solid State Physics - The University of Tokyo, Japan - Ser. B., No. 21, Sept 1984, pages 1 to 29). In order to guarantee an unchanged position of the windings of these windings to be created from appropriate conductors, these windings must first be wound around a correspondingly shaped winding core and fastened to this. However, this poses the problem of winding with a negative radius of curvature in the region of the concave inner sides of such winding cores.

Magnets whose windings have negative curvatures can, for example, by. draft-free laying of the at least one conductor in grooves and subsequent wedging. A successive clamping of the conductor using special pressure elements such. B. individual, on the outer edge of a correspondingly shaped winding core to be fixedly known clamps. The conductor pieces clamped with these elements must then be fixed, for example glued, piece by piece to the winding core or, if appropriate, to conductor windings already applied to these. Such winding techniques are, however, particularly for the production of superconducting dipole magnets. of storage rings very complex and time consuming.

The object of the present invention is therefore to create a method with which a large-scale production of disk-shaped, curved magnet coils is made possible in a relatively simple manner, in particular superconducting conductors to be provided.

This object is achieved for the above-mentioned method in that a shaped body of predetermined shape is first added to the winding core, so that a provisional winding body with only positive radii of curvature of its outer sides and at least approximately the same outer circumference as the winding core is formed, that then around this Winding body, the conductors are wound under tension, which are then attached only to the winding core of the winding body, and that after removal of the molded body, the exposed conductor parts facing the region of the concave inside of the winding core are pressed against this inside and fixed there.

The advantages associated with this embodiment of the method are to be seen in particular in the fact that the winding body composed of the winding core and the shaped body has only positive radii of curvature, so that the individual conductors can be wound around it without difficulty under tension. The concave inside of the coil to be created is then obtained by forming the corresponding long side of the curved winding after removing the shaped body by pressing the conductors on this side against the concave inside of the winding core. In this relatively simple manner, a coil with a negative curvature can thus be created without the need for a special, generally very complex fixation of the entire turns during the winding process.

The method according to the invention can advantageously be carried out with a device for which a lenticular fitting piece, which is to be positively attached to the concavely shaped inside of the winding core, is provided as the shaped body. A particularly simple construction of the provisional winding body is possible with such a shaped piece.

Another device for carrying out the method according to the invention contains a composite molded body which has at least two molded parts adjacent to the strongly curved end pieces of the winding core and at least one connecting part extending between these molded parts, the transition from the convex outside of the winding core to the respective molded part of the Shaped body a predetermined piece of that Corresponding end piece of the winding core is removed and a stronger curvature of the shaped parts is provided in predetermined areas, so that after creating the provisional winding around the winding body, removing the shaped body and pressing the thus free winding parts onto the concave inside of the winding core, the previously on the Curved areas of the molded parts adjacent to the molded parts are located at least approximately at the strongly curved ends of the winding core. In this way, mutual movements of the conductors and thus uneven stretching can be kept to a minimum during the winding process.

Advantageous refinements of the devices for carrying out the method according to the invention and advantageous uses of the same are evident from the remaining dependent claims.

To further explain the invention, reference is made to the drawing, in which FIG. 1 indicates the manufacture of a curved, disk-shaped magnetic coil with a device suitable for this purpose. Figure 2 shows schematically a special embodiment of a corresponding magnetic coil. FIGS. 3 and 4 schematically illustrate a further device for carrying out the method according to the invention during different process sections. Corresponding parts in the figures are provided with the same reference numerals.

A plan view of a planar winding core 2 can be seen schematically from FIG. 1, as can be provided, for example, for producing a planar dipole magnetic coil for an electron storage ring. The winding of the coil is to be created with at least one flat, in particular superconducting conductor. The winding core 2, which extends along a predetermined arc length b with an arc or curvature radius p, has a constant width of 2 x D. The size D is the distance from the arc line b to the two concentrically curved long sides 3 and 4 of the winding core 2 This constant width of the winding core extends over an arc length π. α °. p / 180 °, where a ° is the central or arc angle measured in degrees. The front end pieces 5 and 6 of the winding core 2 are formed by semicircles with diameters of 2 × D each. The convex-shaped outer side 4 to be wound is thus connected to the concave-shaped inner side 3 of the winding body 2 via these semicircles.

Before the actual winding process, an approximately lenticular adapter 7 is positively attached to this concave-shaped inside 3 of the winding core 2 as a shaped body, which has the height of the conductor to be wound and the outside 8 of which is to be wound tangentially to the end pieces 5 and 6 of the winding core 2 creates. This adapter therefore has a radius of curvature of pD on the side facing the winding core 2 over an arc length ( _T7 / 180) - a - (pD). This part of the adapter is followed by arcs on both sides with the radius of curvature D and the arc angle a. The outside 8 of the fitting 7 to be wound preferably has a radius of curvature p + D and also an arc angle a.

On the winding body 10 thus formed from the winding core 2 and the fitting 7, the coil conductors 11 are now wound into a winding package with a constant width under tension, the same distance between the individual conductor turns being maintained. Since the radii of curvature are always positive, there is advantageously no fear of the conductors 11 bent under the radius of curvature D at the end pieces 5 and 6 at the end faces. After the winding thus created is only fastened to the coil core 2, for example clamped, the fitting 7 can be reduced in size and removed. A subsequent pressing of the conductor parts located in the area of the free concave inner side 3 of the winding core 2 then takes place on this longitudinal side as if each turn individually lies against the winding core 2 with an adapted length. Due to the predetermined radius of curvature 'of the outside 8 of the fitting 7 to be wound, it is ensured that the conductor lengths in the individual turns before and after pressing on remain at least largely constant, thus avoiding compression or overstretching of the conductor. In the figure, the pressed-on conductor parts are denoted by 11 'and indicated by dashed lines. A loosening of the clamps holding the winding on the winding core is therefore not necessary. Since the adapters have exactly the height of the conductor of the turns, double disks can advantageously be wound one after the other. Superconducting dipole magnetic coils are generally constructed from such double disks.

According to the exemplary embodiment according to FIG. 1, it was assumed that the shaped body in each case only comprises a single adapter 7 per disk-shaped winding and that the conductors abut one another in a form-fitting manner on the end pieces 5 and 6 of the winding core 2. However, as can be seen from the schematic top view of a further exemplary embodiment of a magnet coil to be produced according to the invention, which is shown in FIG. 2, conductor thinning can also be achieved at the front ends of the coil. According to the method described with reference to FIG. 1, a partial winding 15, 15 'is first constructed around a central, curved winding core 2 using an approximately lenticular adapter 7. Half-moon-shaped fits 18 and 19 are then positively attached to this created, curved partial winding in the region of their front ends 15a and 15b. These fits 18 and 19 together with the central winding core 2 and the partial winding arranged around it lung 15, 15 'is a further, larger, also curved winding core, to which a further approximately lenticular adapter is then attached in accordance with the method according to the invention, so as to obtain a larger winding body with only positive curvature of its long sides. This larger winding body is wound as in the first partial winding. The larger partial winding obtained in this way, enclosing the first partial winding 15, 15 ', is designated 16, 16' in the figure. In a corresponding manner, further partial windings can then be created. According to the illustrated embodiment, a third partial winding 17, 17 'is assumed. The figure has been omitted from the figure for reasons of clarity.

As can be seen in particular from FIG. 1, the exemplary embodiments were based on curved winding cores whose center or arc angles α are chosen to be less than 90 °. However, the method according to the invention is not limited to winding cores with arc angles up to this size. Rather, curved winding cores with arc angles of up to 180 ° can also be wound in a corresponding manner. In the case of a = 180 °, the winding core and fitting pieces can then together form, for example, an approximately circular winding body.

In the exemplary embodiments shown in FIGS. 1 and 2 of disk-shaped magnetic coils to be produced according to the invention, it was further assumed that the fitting pieces each have a radius of curvature on their outside to be wound, which is due to the radius of curvature of the arc length of the central winding core, its width and its arc angle is determined. If necessary, however, the outside of these adapters to be wound can also have a differently curved shape. The only requirement for this is that there are no negative radii of curvature and the length of the outside of the fitting to be wound is selected so that the conductor lengths in the individual turns before and after the pressing process are at least largely constant. An embodiment of a corresponding shaped body is shown in Figure 3.

A planar winding core 20 can be seen schematically from this FIG. 3, which is to be provided with a winding according to the method according to the invention. The winding core 20, which extends along a predetermined arc length b 'with an arc or curvature radius p', has a constant width of 2 x D 'between its two concentrically curved longitudinal sides 23 and 24. According to the exemplary embodiment shown, the central or arc angle α have a value of 180 °. The front end pieces 25 and 26 of the winding core 20 are formed by semicircles with diameters of 2 × D 'each.

Before the actual winding process, a shaped body 28 that can be assembled from several pieces is added to the winding core 20 according to the invention. This molded body comprises two outer molded parts 29 and 30 which are to be attached essentially to the convex outer side 24 in regions 32 and 33 adjacent to the end pieces 25 and 26, wherein they lie tangentially on the winding core 20 at transition points 35 and 36. These outer molded parts 29 and 30 are assembled with a single or multi-part connecting part 37 (37a and 37b) extending between them on the side facing the concave inside 23 of the winding core 20 to form the molded body 28. The connecting part 37 can be designed in any way on its inside 38 and, for example, lie against the inside 23 of the winding core 20. In the illustrated embodiment, a flat shape is assumed. The molded body now forms, together with the winding core 20, a provisional winding body 39 with only positive radii of curvature on its outer sides, its outer circumference advantageously being at least approximately equal to the outer circumference of the winding core 20.

The transition points 35 and 36 between the winding core 20 and the outer molded parts 29 and 30 are advantageously at a predetermined distance e from the respective end pieces 25 and 26. According to the illustrated embodiment, it is assumed that e makes up an arc length that is about 1/4 corresponds to the arc length b ', ie the following applies: e = (b' / 4) + (π. c ^t '/4.D')/180 ^0. In addition, the molded parts 29 and 30 are advantageously designed such that they each have one have more curved areas 40 and 41 of their outer sides 42 and 43 at a predetermined location. The position of these areas is determined by the fact that after the winding body 39 has been wound with a provisional winding 45, the winding parts 46 and 47 initially resting on these areas in the finally created curved winding are at least approximately at the areas of the strongly curved end pieces 25 and 26 of the winding core 20.

In order to convert the provisional winding 45 into the desired final shape, first, as is to be indicated in FIG. 3 by arrowed lines 48, the winding part of which, in the region 49 of the non-changing winding core 20, is pressed onto it or fastened, for example clamped, to it . After the attached pieces 29, 30, 37 of the shaped body 28 have been removed, the free conductor parts 50 of the provisional winding 45 are then pressed against the concave inside 23 of the winding body 20 with a force K by means of a specially shaped pressing piece 52. The predetermined outer circumference of the molded body 28 ensures that the conductor lengths in the individual turns before and after pressing on remain at least largely constant, thus preventing the conductors from being compressed or overstretched.

The winding deformed in this way is correct in FIG illustrated mathematically as supervision and designated 45 '. In the area of the concave inside 23 of the winding core 20, the winding is held in a form-fitting manner by the pressure piece 52 on this inside due to a holding force K '. For this purpose, as can also be seen in particular from this figure, the contact piece 52 must have a curved outer face 53 which deforms the winding and whose radius of curvature r is adapted to that of the winding and thus to the radius p 'of the winding core 20. In other words, the following roughly applies: r = p '- D'- s, where s is the radial expansion of the winding 45' on the concave inside 23 of the winding core 20.

After the winding 45 has been pressed on, it can then be solidified by means of a hardenable plastic. As is also indicated in FIG. 4 by arrowed lines 55, after removing the pressure piece 52, the conductor parts resting on the concave inside 23 of the winding core 20 can still be attached to this side, for example clamped, for example.

The molded body 28 with its molded parts 29 and 30 and the connecting part 37 can have exactly the height of the conductor of the turns to be created, so that double disks can be wound one after the other.

Claims (11)

1. A process for manufacturing a curved disc- shaped magnet coil, in particular for an apparatus for the acceleration and/or storage of electrically charged particles such as electrons, in which the conductors of the coil to be formed are arranged around a winding core (2, 20) which has a convex- shaped outer side and a concave-shaped inner side, and' consequently a partly negative curvature; and are subsequently fixed in their corresponding position, characterised in that a shaped body (7, 28) of a predetermined shape is first attached to the winding core (2, 20) so as to form a temporary winding body (10, 39) with only positive radii of curvature on its outer sides, in that the conductors (11), which are subsequently fixed only on the winding core (2, 20) of the winding body (10, 39), are then wound under tension around this winding body (10, 39), and in that after removal of the shaped body (7, 28) the conductor parts (11', 50) which are thus exposed and face the region of the concave inner side (3, 23) of the winding core (2, 20), are pressed against this inner side (3, 23) and fixed in place there.

2. A device for carrying out the process according to claim 1, characterised in that the shaped body provided is a generally lenticular adaptor (7) which may be attached by form-locking to the inner side (3) of the winding core (2).

3. A device according to claim 2, characterised by the provision of a winding core (2) curved along a central arc length (b) with an at least approximately constant distance (2D) between its long sides (3, 4) and semi-circular end-pieces (5, 6) at its ends.

4. A device according to claim 3, characterised in that the generally lenticular adaptor (7) has a radius of curvature p-D with an arc length of π/180° · α· (p-D) on the side facing the winding core (2) and a radius of curvature p + D on its outer side (8) that is to be wound, where p is the radius of curvature of the central arc length (b) of the winding core (2),

a is the angle subtended by the arc length (b) and

D is the radius of the end-pieces (5, 6) at the ends.

5. A device for carrying out the process according to claim 1, characterised by a composite shaped body (28) which has at least two shaped parts (29, 30) adjoining the sharply curved end-pieces (25, 26) of the winding core (20) and at least one connecting part (37) which extends between these shaped parts (29, 30), the transition (35, 36) from the convex outer side (24) of the winding core (20) to the respective shaped part (29, 30) of the shaped body (28) being a predetermined distance (e) from the corresponding endpiece (25, 26) of the winding core (20) and the curvature of the outer sides (42, 43) of the shaped parts (29, 30) being sharper in predetermined regions (40, 41), so that, after the temporary winding (45) has been formed around the winding body (39), the shaped body (28) has been removed and the parts (50) of the winding thereby freed have been pressed against the concave inner side (23) of the winding core (20), the parts (46, 47) of the winding which previously adjoined the more sharply curved regions (40, 41) of the shaped parts (29, 30) lie at least approximately on the sharply curved end-pieces (25, 26) of the winding core (20).

6. A device according to claim 5, characterised in that the winding core (20) is curved along a central arc length (b') and the distance (2D) between its long sides (23, 24) which extend between the semi-circular end-pieces (25, 26) is at least approximately constant.

7. A device according to claim 6, characterised in that in each case about 1/4 of the convex outer side (24) of the winding core (20) which extends between the end-pieces (25, 26) at the ends is to be covered by the shaped parts (29, 30) of the shaped body (28).

8. A device according to any one of claims 5 to 7 characterised by a pressure member (52) which may be used to attach the free parts (50) of the temporary winding (45) to the concave inner side (23) of the winding core (20), and of which the shape of the corresponding outer side (53) is adapted to the curvature of the finished winding (45').

9. A device according to any one of claims 2 to 8, characterised in that the circumference of the temporary winding body (10, 39) is at least about the same as the circumference of the winding core (2, 20).

10. The use of the device according to any one of claims 2 to 9 for forming the winding (11, 11'; 15, 15'; 16, 16'; 17, 17'; 45, 45') of the magnet coil with superconducting conductors.

11. The use of the device according to any one of claims 2 to 9 for forming the magnet coil from one or more flat windings, in particular of superconducting conductors.

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