JPH0624165B2 - Method for manufacturing thin superconducting coil - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method of manufacturing a thin-walled superconducting coil for a detector of collision reaction particles such as electrons or protons.

This type of coil needs to generate a strong electromagnetic field efficiently and uniformly. For this reason, in the superconducting state, a direct current of several thousand amperes is passed through the coil to significantly reduce the conductor cross-sectional area, and a return iron core is mounted around the coil in order to return the magnetic flux generated from the superconducting coil. To be done. However, in such a configuration, if the magnetic center of the coil and the magnetic center of the return iron core do not match, an axial electromagnetic thrust acts between them and the coil or the coil support structure is destroyed. There is a problem, and it is required to establish a method of manufacturing a superconducting coil in which the magnetic centers of the coil and the iron core are well matched.

[Prior art and its problems]

FIG. 1 is a sectional view showing a method of manufacturing a conventional thin superconducting coil. In the figure, reference numeral 1 denotes a superconducting coil, which is a tubular shape made of a metal tubular winding frame 2 and a rectangular superconducting body (hereinafter referred to as a superconducting wire) closely insulatively coated on the inner peripheral surface of the winding frame 2. The tubular coil is composed of the coil 3 and the tubular coil 3 and the bobbin 2 are integrally formed between the superconducting wires by an adhesive or the like while a predetermined surface pressure is applied in the axial direction and the radial direction. The superconducting coil 1 is fixed and fixed.
Next, a method of manufacturing the superconducting coil 1 will be described with reference to FIG. Reference numeral 4 is a coil receiver having a tubular fitting portion 4a which is fitted inside the winding frame 2 and regulates a winding start position (position a) of the tubular coil 3. First, one end of the winding frame 2 is coiled. Four
Insert and fix. Next, the tubular coil 3 is wound a predetermined number of times N times while applying pressure such that the outer peripheral surface of the coil closely contacts the inner peripheral surface of the winding frame 2 in the left direction of the drawing starting from the position a. Then, the pressurizing jig 5 having the tubular fitting portion 5a is inserted from the other end of the winding frame 2, and a load P is applied in the axial direction of the tubular coil 3 to press the tubular jig 3 to set the winding end position of the tubular coil 3. Compress until reaching a predetermined position b. Then, the coil receiver 4 and the pressurizing jig 5 are connected by a pressure holding bolt or the like (not shown), and the superconducting coil 1 is put in a heating and hardening furnace and heated while the load P applied to the end face of the tubular coil 3 is held. . At this time, if the insulating coating of the superconducting wire forming the tubular coil 3 is previously coated with an adhesive or the like, the tubular coil 3 and the winding frame 2 are fixed and integrated with each other by heating and curing. . The superconducting coil formed in this way can sufficiently function the metal reel 2 as a reinforcing member against the electromagnetic force in the radial direction and the internal compressive force in the axial direction generated by the large current flowing in the coil. It is possible to generate a strong electromagnetic field with a thin superconducting coil.

However, when the cylindrical coil 3 is wound, the superconducting wire is wound while applying a radial pressure to expand the winding frame 2 in the radial direction, and therefore, there is a slip between the winding frame 2 and the cylindrical coil 3. Friction resistance occurs. Therefore, when the load P is applied in the axial direction of the tubular coil 3 by the pressing jig 5 and the coil receiver 4 and the pressing jig 5 are connected by the pressure holding bolt to hold the load P, Since 4 is fixed by the winding frame 2, movement in the axial direction is restricted, and no surface pressure is applied from the coil receiver 4 to the end surface of the tubular coil 3. Therefore, the surface pressure P acting between each winding of the cylindrical coil is reduced by the sliding friction resistance, and as shown in FIG. As the distance increases, the distribution sharply decreases, and the distribution becomes non-uniform in the axial direction such that it becomes minimum at the portion a farthest from the pressing jig.
The superconducting coil for the collision reaction particle detector has a length of one.
Some of them extend up to around 10 meters, and the number of turns of the superconducting wire is extremely large. Therefore, when the difference in surface pressure between turns, in other words, the difference in insulation dimensions between turns, accumulates in the coil axis direction. A considerable difference occurs in the winding number density (the number of windings per unit length in the axial direction). That is, in FIG. 1, the axial length of the winding frame is L, and its axial center position is O _1, and the entire winding is between a and b that are inwardly equal in size from both ends A and B of the winding frame. A number N of cylindrical coils 3 are wound,
Positions (hereinafter referred to as the magnetic centers of the tubular coil) that are located in the coils addressed to ½ of the total number of turns from the positions a and b are referred to as o. When the surface pressure distribution of the cylindrical coil 3 is as shown in FIG. 2, the magnetic center o of the cylindrical coil moves from the center position of the winding frame 2 toward the pressing jig 5 side by Δl.

In Figure 3 is a schematic cross-sectional view of a conventional collision reaction particle detector, bobbin 2 so that the magnetic center position O ₂ is coincident axial center position O ₁ and return core 6 of the bobbin 2 in the return core 6 Fixed. At this time, since the magnetic center o of the tubular coil deviates from the magnetic center O ₂ of the return iron core 6 by Δl, the magnetic flux φ at both ends of the tubular coil does not have a bilaterally symmetrical distribution as shown in the figure. Therefore, there is a problem in that the electromagnetic mechanical force acting in the axial direction of the tubular coil is different at both ends of the tubular coil, and the electromagnetic thrust acts on the tubular coil. In this way, the external thrust acting in the axial direction of the tubular coil is 10 when Δl is 10 mm, for example.
^In some cases, the force may reach as high as ⁴ Kg, and the superconducting coil or supporting structure could not withstand such external thrust and was damaged.

[Object of the Invention]

The present invention has been made in view of the above situation, and the axial center position of the metal reel and the magnetic center position of the tubular coil match, and the magnetic center position of the tubular coil with respect to the magnetic center position. It is an object of the present invention to provide a method for manufacturing a thin-walled superconducting coil in which the surface pressure axial distribution is symmetrical.

[Main points of the invention]

According to the present invention, the above-described object is to close the inner peripheral surface of the tubular winding frame and to wind the tubular coil, in which each of the tubular coils is directed to a half of the total number of turns. First and second partial coils are respectively wound in both directions starting from the axial center position of the winding frame, and the first and second partial coils are separately wound around the winding start position as a fulcrum. From the idea that axially opposite loads are applied to the coil end faces from the above, the axial center position of the winding frame and the magnetic center position of the cylindrical coil are coincident with each other, and the surface pressure is symmetrical with respect to the center position. Distribution In other words, it is a coil that can generate a symmetrical magnetic flux distribution. Specifically,
The winding frame is fixed to a tubular coil receiver that is inserted into the winding frame from one end of the winding frame and is regulated so that the tip end position of the fitting insertion portion coincides with the axial center position of the winding frame, A first step of forming a first partial coil by winding the superconducting wire toward the winding frame and the other end, starting from the front end of the coil receiver, and halving the total number of turns of the tubular coil; A cylindrical first pressing jig is inserted from the other end of the winding frame to apply a predetermined surface pressure to the end surface of the first partial coil, and the first portion is held while maintaining the surface pressure. The second step of fixing the coil to the inner peripheral surface of the winding frame, the fixing of the winding frame to the first pressure jig to remove the coil receiver, and the winding start position of the first partial coil. To the second portion by winding the remaining half of the total number of turns of the tubular coil in the direction opposite to the first partial coil. And a fourth step of inserting a cylindrical second pressing jig from one end of the winding frame and applying a predetermined surface pressure to the end surface of the second partial coil. This is achieved by the fifth step of heating and solidifying the second partial coil and the first partial coil and the winding frame while maintaining this surface pressure.

Example of Invention

4 to 7 are conceptual views for explaining the manufacturing method of the present invention. First, the first and second steps will be described with reference to FIG. Reference numeral 11 denotes a coil receiver, which is composed of a tubular fitting portion 11 a and a flange portion 11 b which are fitted and inserted inside the tubular winding frame 2, and the tip of the fitting portion 11 a is the axial center of the winding frame 2. The flange portion 11 b has one end surface A of the winding frame 2 aligned with the position O _1.
The position of the bobbin 2 is regulated by abutting on the reel part.
Is fixed to the coil receiver 11. Reference numeral 12 is a first partial coil, which starts winding the end surface o of the coil receiver 11 and applies a flat superconducting wire with prepreg insulation coating to the inner peripheral surface of the winding frame 2 while applying outward pressure to the total number of windings of the tubular coil. And the first step is completed. Next, the pressing jig 13 is fitted into the winding frame 2 from the other end of the winding frame, and the axial load P is applied to the winding end face b of the first partial coil. At this time, the load P is the winding start end surface o of the first partial coil.
Acts as a fulcrum to compress the winding in the axial direction, but since one end of the winding frame 2 is fixed to the coil receiver 11, the contact surface between the winding frame 2 and the first partial coil 12 is Due to the sliding frictional resistance, the surface pressure p between each winding in the partial coil is not uniform and is highest at the pressing end b portion and exponentially decreases in the coil as shown in FIG. Distribution. However, since the axial length of the coil and the number of turns are both half of the conventional one, the sliding friction resistance also decreases, and the difference in the surface pressure distribution between the pressurizing point and the supporting point is better than that of the conventional method. Decreases. Next, while maintaining the distribution of the surface pressure p given to the first partial coil by the pressing jig 13, the first partial coil 12
Is fixed to the bobbin 2. For example, the coil receiver 11 and the pressing jig are fixed.
The first cylindrical coil and the winding 13 are housed in a heating and drying furnace in a state where both flanges are connected to each other by connecting bolts (not shown), and the adhesive or the like previously applied to the superconducting wire is cured by heating. The frame can be integrated. A so-called B-stage prepreg insulation coating obtained by impregnating a glass cloth tape with epoxy resin or the like and heating and drying it is suitable as the insulation coating for the superconducting wire. When the resin is heated in a state where a load is applied in the direction, the resin in the insulating coating softens and exudes to the adhesive surface to fill the voids, and the superconducting wires and the superconducting wire and the bobbin can be completely integrated. If necessary, an adhesive resin is applied to the inner peripheral surface of the winding frame in advance.

The winding frame 2 to which the first partial coil is fixed is fixed to the first pressing jig 13 side and the coil receiver 11 is removed. At this time the first
Instead of the pressure jig 13, the coil holder 14 may be replaced with another coil receiver 14 having a flange portion that comes into contact with the other end surface of the winding frame 2 at the position B as shown in FIG. In any case, on the inner peripheral surface of the winding frame 2 supported on the other end B side of the winding frame 2, a superconducting wire conductively connected to the winding start end of the first partial coil 12 is provided on one side of the winding frame 2. The second partial coil 15 is formed by winding the remaining one-half of the total number of turns of the tubular coil toward the end B side. This is the third step. Next, the second pressurizing jig 16 is inserted and inserted from the one end A side of the winding frame, and the axial load P in the direction opposite to the second step is applied to the winding end face of the second partial coil 15 in the first direction. The winding end face of the second partial coil 15 is compressed to the position a. At this time, since the first partial coil 12 is already fixed to the winding frame 2, the second partial coil 15 is axially compressed with the o position as a fulcrum, and the axial surface pressure generated between the windings is As shown in FIG. 7, the distribution is highest at the position a and decreases exponentially inside the coil. As a result, the distribution becomes symmetrical with the surface pressure distribution inside the first partial coil 12, the magnetic center position o coincides with the axial center position O of the winding frame 2, and the surface pressure distribution with respect to the magnetic center position o. A symmetrical superconducting coil is formed. This is the fourth step. Next, the pressurizing jig 16 and the pressurizing jig (or coil receiver) 14 are connected by a pressure holding bolt or the like (not shown) to hold the surface pressure,
The second partial coil 15 is housed in a heating / drying furnace while radially applying a radial pressure from the inner peripheral surface, and the insulating coating containing the adhesive resin and the like adhered to the superconducting wire is cured by heating, so that the entire superconducting coil is formed. Unify. The superconducting coil that has been cured by heating is returned to room temperature, and then the jigs are removed to complete the fifth step.

In the above description of the embodiments, the case where the first partial coil is heat-cured in the second step and the second partial coil is heat-cured in the fifth step has been described. Then, a constraining jig such as an lining spring is attached to the inner peripheral surface side of the first partial coil to maintain the surface pressure, and the first and second partial coils are simultaneously heat-cured in the fifth step. It is also possible to do so. In this case, prepreg insulation is applied to the insulation coating of the superconducting wire and the inner peripheral surface of the winding frame,
It is more effective if the prepreg insulating members adhere to each other by the pressure in the radial direction and the axial direction applied to the first partial coil in the step of (1) to hold the surface pressure. By configuring the manufacturing method of the superconducting coil in this way, the second step is simplified, and the first partial coil is heat-cured twice so that the first heat-cured adhesive is integrated. This has the effect of preventing deterioration such as peeling of the surface due to the second heating. In the above-mentioned embodiment, if the tubular coil is divided into a plurality of pairs of partial coils, the surface pressure distribution between the windings can be made more uniform.

Next, a method of winding the partial coil in the present invention will be described. 8 and 9 are conceptual diagrams for explaining the winding method of the partial coil. First, in FIG. 8, when the first partial coil 12 is wound in close contact with the inner peripheral surface of the cylindrical winding frame 2, the winding machine first supported rotatably and inserted into the winding frame 2. At 21, a superconducting wire having a length required to wind the first partial coil 12 is wound in a direction opposite to the winding direction of the first partial coil 12 to form a temporary winding coil 22, and a winding end end is formed. The corresponding part is fixed to the winding machine 21. Next, the winding start end is a guide roller
It is guided to the reel 2 via 23 and fixed. Next, the winding machine 21 is rotated in the direction in which the temporary coil 22 is rewound, and the superconducting wire is wound onto the bobbin 2.
The first partial coil 12 is wound a predetermined number of times by being guided by the guide roller 23 so as to be pushed into the inner peripheral surface of the.
When the second partial coil is wound in the third step as well, a temporary coil corresponding to the second partial coil is inserted into the winding edge machine in the same manner as described above, and each of the first and second partial coils is wound. After the starting end is conductively connected, it is wound a predetermined number of times. In this way, the first and second partial coils can be wound closely on the inner peripheral surface of the winding frame 2.

FIG. 9 shows a method of winding the first and second partial coils by using one superconducting wire without a connecting portion. In this embodiment, first, the superconducting wire required to wind the entire number of turns of the tubular coil is wound around the winding machine 21 to form the temporary winding coil 24. Next, the center of the temporary winding coil 24 is guided to the axial center position of the winding frame 2 fixed to the coil receiver 11 via the guide roller 23. At this time, the end of the temporary coil 24a corresponding to the first partial coil is The temporary coil 24b, which is fixed to the winding machine 21 and corresponds to the second partial coil, does not fix the end portion and is free. In this way, in the first step, the winding machine 21 is rotated in the direction in which the temporary coil 24a is rewound to form the first partial coil. In this case, since the temporary coil 24b is not constrained at its end, the elasticity of the superconducting wire causes a plurality of guide rollers 23b.
The coil is unwound to some extent within the range of the diameter regulated by the above, and when the winding machine is rotated, it freely slides around the winding machine, so that there is no hindrance to the work of winding the first partial coil. When the second partial coil is wound in the third step, the terminal end of the temporary coil 24b is fixed to the winding machine 21 and the temporary coil 24b is rewound in other words, in other words, the first partial coil is wound. It is rotated in the opposite direction to the case where it is turned and wound a predetermined number of times. In this way, the superconducting coil including the first and second partial coils can be seamlessly formed. Generally, an extremely thin superconducting wire is embedded in a stabilizing material such as pure aluminum to connect a superconducting wire, which requires a high level of technology, but provides a method for producing a seamless coil as in the above-described embodiment. As a result, it is possible to provide a highly reliable thin superconducting coil that does not require high technology.

〔The invention's effect〕

According to the present invention, in manufacturing a tubular superconducting coil which is in close contact with and integrated with the inner peripheral surface of a metallic tubular winding frame, the tubular coil is formed into first and second partial coils. The winding is started at the center position in the axial direction of the winding frame and wound toward different ends of the winding frame, and the first partial coil is first pressed in the axial direction with the winding start position as a fulcrum. Provided is a method of manufacturing a metal-conducting superconducting coil configured to be fixed to a frame and then to press the second partial coil in a direction opposite to that of the first partial coil to be fixed to the winding frame. As a result, the axial center position of the winding frame and the magnetic center position of the coil completely match,
Moreover, it is possible to manufacture a superconducting coil having a symmetrical surface pressure distribution or magnetic flux distribution with respect to the axial center position. Therefore, when the thin superconducting coil manufactured by the method of the present invention is applied to, for example, a collision reaction particle detector, if the two are combined so that the axial center positions of the bobbin and the iron core coincide with each other, the superconducting coil flows. It is possible to provide a device that has the least electromagnetic mechanical force generated by a large current, especially the electromagnetic thrust. In addition, the weight and simplification of the coil support structure can be achieved. In addition, the above-mentioned effects act synergistically, which can contribute to providing a superconducting device that is stable and highly reliable against electromagnetic mechanical force.

[Brief description of drawings]

1 to 3 are conceptual views for explaining a conventional thin-walled superconducting coil and a manufacturing method and problems, and FIGS. 4 to 7 are for explaining a manufacturing method and features of the thin-walled superconducting coil of the present invention. And FIGS. 8 and 9 are conceptual diagrams for explaining the winding method of the thin superconducting coil of the present invention. In the figure, 1 ... Thin superconducting coil, 2 ... Cylindrical winding frame, 3 ... Cylindrical coil, 4, 11, 14 ... Coil receiver, 12
...... First partial coil, 15 ...... Second partial coil, 13 ...
… First pressurizing jig, 16 …… Second pressurizing jig, 22,24 ……
Temporary winding coil, O ₁ ... axial center position of winding frame, o ... magnetic center position of tubular coil.

Claims (6)

[Claims] 1. A superconducting wire covered with a prepreg insulating coating is wound in close contact with an inner peripheral surface of a cylindrical winding frame to form a single-layer cylindrical coil having a predetermined number of turns, and then the prepreg insulating coating is cured by heating. In the method of integrating with a winding frame, the superconducting wire is wound toward one end of the winding frame starting from a central position in the axial direction of the winding frame by ½ of the total number of turns of the tubular coil. Forming a partial coil, pressurizing the first partial coil in the axial direction with respect to the central position in the axial direction, and then maintaining the applied pressure and directing the axial central position toward the other end of the winding frame To form a second partial coil by winding the superconducting wire by the remaining number of turns of the tubular coil, and pressurizing the second partial coil at the same axial pressure as the pressing force. A method for producing a thin superconducting coil. 2. The method according to claim 1, wherein in the manufacturing process, one end of the winding frame is inserted into the winding frame and a tip end position of the fitting insertion portion is a center position in the axial direction of the winding frame. The winding frame is fixed to a cylindrical coil receiver regulated so as to match with, and the superconducting wire is wound toward the other end of the winding frame starting from the leading end of the coil receiver to the total number of turns of the cylindrical coil. First wound by half to form a first partial coil
And the step of inserting the cylindrical first pressing jig from the other end of the winding frame to apply a predetermined surface pressure to the end surface of the first partial coil, Second step of fixing the partial coil to the inner peripheral surface of the winding frame, fixing the winding frame to a first pressing jig to remove the coil receiver, and the winding start position of the first partial coil. From the first partial coil in the opposite direction to the other half of the total number of turns of the tubular coil.
A third step of forming a second partial coil by winding
A fourth step of inserting a cylindrical second pressing jig from one end of the winding frame to apply a predetermined surface pressure to the end surface of the second partial coil, and a second step while maintaining this surface pressure. A fifth step of fixing the partial coil to the inner peripheral surface of the winding frame, the method for producing a thin superconducting coil. 3. The restraint jig according to claim 1 or 2, wherein each partial coil is wound and pressurized, and a radial pressure is applied from the inner peripheral surface side of the partial coil toward the outside. And heating the whole to a predetermined temperature to heat and cure the prepreg insulating coating to integrate the partial coils with the winding frame, respectively. 4. A method for manufacturing a thin superconducting coil according to any one of claims 1 to 3, wherein the prepreg insulating coating of each partial coil is heat-cured at the same time. 5. A method according to any one of claims 1 to 4, wherein the third step conductively connects the winding start ends of the first and second partial coils, respectively. A method of manufacturing a thin-walled superconducting coil, which comprises the steps of: 6. The method according to any one of claims 1 to 5, wherein in the first step, the superconducting wire having a length corresponding to the total number of turns of the tubular coil is previously provided in the tube. Formed into a temporary coil having a diameter smaller than that of the spiral coil, and the temporary coil is rotatably inserted into the winding frame, and the central portion of the temporary coil is guided to the axial central portion of the winding frame. Winding the first partial coil while rewinding half of the coil, and winding the second partial coil of the first partial coil while rewinding the other half of the temporary coil in the third step. A method for manufacturing a thin-walled superconducting coil, characterized in that it is wound continuously with a starting end portion.