JPH0150093B2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a solenoid coil.

[Technical background of the invention and its problems]

FIG. 1 shows a longitudinal sectional view of an example of a magnet system that uses solenoid coils to generate as strong a magnetic field as possible in a space of a predetermined size.
Fig. 1 shows an example in which solenoid coils 1, 2, and 3 wound in a single layer are arranged concentrically with respect to the axis C, and the inner diameter Di of the innermost circumferential coil 1 is set in a space of a predetermined size. Assume that it is specified as .

On the other hand, the strength H of the magnetic field at the center of a single solenoid coil is given by H=n・I・L/√4・² + ² (101). Here, the symbols are as follows: R: Radius of the coil L: Length of the coil in the axial direction n: Number of turns per unit length of the coil in the axial direction I: Current. In equation (101), the magnetic field strength H can be increased by R and L representing the shape of the solenoid coil by appropriately reducing R/L. Next, to increase the magnetic field strength H by n and I, r: Width in the radial direction of the cross section of the coil conductor l: Width in the height direction of the cross section of the coil conductor i: Current density, then i= I/(r・1) …(102) l=1/n …(103) Therefore, (n・I)max=(i・r)max …(104), and the current density i is increased to the allowable limit. At the same time, the conductor width r is increased.

However, if r is increased, the radius of the solenoid coils 2 and 3 will be increased, as is clear in FIG.
If the power supply capacity is limited, the magnetic field strength of the system as a whole will ultimately decrease.

As is clear from the above overview, in the inner circumference side solenoid coil, especially, R is small, L is large,
Also, within the allowable limit for hoop stress, the conductor width r
A small coil is desirable.

On the other hand, a strong compressive force acts on the solenoid coil in the axial direction. An example of the compressive stress generated between turns is shown in FIG. This force is based on the radial component of the magnetic field produced by the coils arranged in layers.

As mentioned above, if a strong compressive force is applied in the axial direction to a solenoid coil that has a long axial length L, a small radius R, and a small radial width r of the conductor, the coil will buckle. There is a possibility that this may occur. This is because the third coil is formed by winding the wire and shaping it.
As shown in the figure, this is because the cross-sectional shape of the conductor 4 is deformed into a wedge shape, so that the insulating material 5 is pushed out toward the outer diameter side, and there is a limit to the shaping accuracy of the conductor.

Therefore, solenoid coils shown in FIGS. 4 to 6 were devised.

FIG. 4 shows the shape of the material 6 of the solenoid coil conductor used in the improved conventional example. The inner/outer surfaces, end faces, etc. have already been machined, and the cutting between the turns remains, making it cylindrical. The small holes 7 are the starting and ending points of the inter-turn cutting process in the next step.

FIG. 5 shows a coil-shaped conductor 8 in which the coil conductor material 6 has been subjected to electrical discharge machining to separate the turns. FIG. 6 shows a partially enlarged section of the coil-shaped conductor 8 including the axis C thereof.
4 is a conductor, and 5 is an insulating member.

In this way, unlike the case where the rectangular conductor shown in Fig. 3 is wound, the adjacent opposing surfaces of the turns always form a helical surface with the generatrix being a parallel line perpendicular to the coil axis C. There is. Therefore, with respect to the axial compressive force (fastening force and electromagnetic compressive force) acting on the coil, causes of decrease in reliability such as buckling of the coil and protrusion of the insulating member 5 are eliminated.

Further, when using electric discharge machining (wire cutting method) as shown in this conventional example, the cutting width between turns can be specified as, for example, 0.09 mm, and the thickness of commercially available insulating member 5, for example, 0.10 mm. It is very convenient to heat and harden the material while compressing it in the axial direction after sandwiching the material. In other words, compared to the case where a rectangular conductor is wound, errors in the coil axis length and inner and outer diameter dimensions due to the springback effect of the conductor are smaller, and the errors are uniform over the entire length, making it easier to maintain the straightness of the coil during use. This has the effect of providing highly reliable products.

Further, by adopting this conventional example, the current output and input at the end of the coil and the support structure can be greatly simplified. In other words, when a rectangular conductor is wound, the end face of the solenoid coil is aligned with the coil axis C.
The current lead must rise. Therefore, the support part requires three-dimensional processing to match the pitch of the conductor, and furthermore, it is impossible to support the rising part of the current lead.
For this type of coil, which requires strong compression and fastening in the axial direction from both ends of the coil, this structure, which can evenly support the entire circumference of the ends, is a highly reliable and inexpensive product. It is effective in providing the following.

Furthermore, by employing this solenoid coil, tool costs can be significantly reduced.
As shown in FIG. 1, this type of magnet system is constructed by combining several or more solenoid coils with different radial dimensions. Therefore, conventionally, it is necessary to prepare conductor manufacturing jigs and winding jigs of different sizes. As mentioned above, the winding precision of the conductor has a significant effect on the reliability and life of the system, so it tends to be extremely expensive, and there are many parts that are inflexible due to differences in size. On the other hand, this solenoid coil can be manufactured in any size using a general-purpose lathe and an electric discharge machine, which greatly contributes to lowering the cost of the product.

However, the above conventional example has the following problems.

First, after the turns are separated, the circumferential position of several tens of turns of the conductor cannot be accurately controlled. In other words, in the curing process of the insulating member, which involves inserting the insulating member between the turns, axially fastening it, and heating it to raise the temperature, it is not possible to completely control the circumferential position of the conductor by controlling the inner and outer diameter dimensions using a jig. It is difficult to predict.

Second, when compressing and shaping the solenoid coil or supporting structure material adjacent to the inner or outer side through an insulating member, if there is an annular gap between the two, buckling deformation may occur.

Third, when cooling water is allowed to flow between the solenoid coils during operation, the cooling water may flow unevenly and the solenoid coil may be deformed.

[Purpose of the invention]

The present invention provides a highly reliable solenoid coil that has good shaping properties, prevents buckling even when force is applied in the axial direction, and prevents uneven flow of cooling water during operation. The purpose is to

[Summary of the invention]

In order to achieve the above object, in the present invention, a cylindrical conductor having an axial protrusion on its inner or outer circumferential surface is subjected to electric discharge machining to separate the parts between turns, and insulate between the turns. By arranging and shaping the members, we improve shaping properties and prevent buckling even when force is applied in the axial direction.
In addition, the solenoid coil is used to prevent cooling water drift during operation.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 7 to 10. In these drawings, the same parts as in FIGS. 1 to 6 are designated by the same cylinder numbers, and their explanations will be omitted. The completed solenoid coil is shown in Figure 1, so please refer to it as well. Figures 7 and 8 are the 4th
Solenoid coil conductor material 6 in the same process as shown in the figure
shows. The difference from FIG. 4 is that an axial protrusion 9 is provided on the outside (or inside) in the radial direction, but the rest is the same as the conventional example shown in FIGS. 4 to 6.

The function of this protrusion 9 is as follows.

First, the protrusions 9 are used to accurately manage the circumferential position of several tens of turns of the conductor after the turns are separated. In the curing process of the insulating material, which involves inserting the insulating material between the turns, axially fastening it, and heating the material to raise the temperature, it is not possible to completely control the circumferential position of the conductor by controlling the inner and outer diameter dimensions using a jig. Difficult to base. always,
By aligning the positions of the protrusions 9 in the circumferential direction and rotating the fastening and heating hardening, the uniformity of the solenoid coil in the longitudinal direction and the radial direction is maintained. Therefore, in this type of manufacturing method, product reliability can be ensured.

The second function is to prevent deformation such as buckling by bringing the solenoid coil into contact with the adjacent solenoid coil or support structure material on the inside or outside through an insulating member (not shown). Each of the conventional solenoid coils 1, 2, and 3 (see Figure 1) expands in the radial direction in accordance with the respective temperature rise and respective hoop stress during operation, and depending on the design, may produce a gap. , or mutually transmitting hoop stress, but this embodiment can prevent this.

Thirdly, when cooling water is allowed to flow between the solenoid coils 1, 2, and 3 in the axial direction, it serves to prevent uneven flow of the cooling water.

〔Effect of the invention〕

As described above, according to the present invention, since axial protrusions are provided on the inner or outer circumferential surface of a conventional cylindrical material, the solenoid coil can be easily shaped, and even when a force is applied in the axial direction. Avoid buckling,
Also, it is possible to prevent cooling water drift during operation.
We can provide highly reliable solenoid coils.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view showing a solenoid coil common to a conventional example and an embodiment of the present invention in an example of a magnet system, and Fig. 2 shows the compressive stress caused by the electromagnetic force in the coil of Fig. 1. Fig. 3 is a longitudinal cross-sectional view showing the shape of the conductor and insulating member in a solenoid coil with conventional rectangular conductor winding, and Fig. 4 is a different and improved version of the one in Fig. 3. FIG. 5 is a partial cross-sectional elevation view showing a solenoid coil conductor material to which a conventional example is applied; FIG. 5 is an elevation view showing a coil shaped conductor shape obtained by cutting the material shown in FIG. 4;
FIG. 6 is an enlarged cross-sectional view of the main part showing the insulating member inserted between the turns of FIG. 5, FIG. 7 is a side view showing the conductor material used in one embodiment of the solenoid coil of the present invention, and FIG. The figure is a partial cross-sectional elevation view of Figure 7.
FIG. 9 is an elevational view showing a shaped conductor shape obtained by cutting the conductor material shown in FIG. 7, and FIG. 10 is an enlarged sectional view of a main part showing a state in which an insulating member is inserted between the turns shown in FIG. 1, 2, 3...Solenoid coil, 4...Conductor, 5...Insulating member, 6...Conductor material, 7...Small hole, 8...Coil shaping conductor, 9...Protrusion.

Claims (1)

[Claims] 1. A cylindrical conductor having an axial protrusion on its inner or outer circumferential surface is subjected to electrical discharge machining to separate the portions between turns, and an insulating member is placed between the turns to shape the conductor. solenoid coil.