JP5942010B2 - Superconducting coil manufacturing method and manufacturing apparatus - Google Patents

Description

  The present invention relates to a method and an apparatus for manufacturing a superconducting coil using a superconducting wire.

Conventionally, superconducting coils have been used in various applications such as magnetic resonance imaging diagnostic equipment (MRI), nuclear magnetic resonance spectroscopy equipment (NMR), and superconducting magnetic energy storage equipment (SMES). Until now, metallic superconductors such as NbTi have been widely used as superconducting wires for these applications, but in recent years Bi2212 (Bi ₂ Sr ₂ CaCu ₂ O _{8 + δ} ), Bi2223 (Bi ₂ Sr ₂ Ca ₂ Cu). Development of oxide high-temperature superconducting wires such as bismuth-based superconducting wires such as ₃ O _{10 + δ} ) and yttrium-based superconducting wires such as RE123 (REBa ₂ Cu ₃ O _7-δ , RE: rare earth elements such as yttrium) has been promoted. Yes.

  Since oxide high-temperature superconducting wires can be used at higher temperatures than metal superconducting wires, application development to superconducting coils and the like is also underway. Most oxide superconducting wires currently provided are in the form of tapes. As a superconducting coil using such a tape-shaped oxide superconducting wire, a pancake coil, a double pancake coil, or an oxide superconducting coil configured by stacking a plurality of these coils is known (for example, a patent) Reference 1).

  Oxide high-temperature superconducting wire has a structure in which thin layers are laminated in multiple layers on a metal substrate. A multilayer composite with a protective layer such as silver and a stabilizing layer such as copper (plating or tape) on the superconducting layer. It has a structure. Conventional superconducting coils using metallic superconducting wires have a low superconducting transition temperature, so they are often cooled with expensive liquid helium, etc., whereas oxide superconducting wires have a relatively high superconducting transition temperature. It can be cooled and operated with inexpensive liquid nitrogen.

JP2013-55311A

  In a superconducting coil in which superconducting wires are wound in multiple layers on a bobbin, the spacing between the superconducting layers of the wire becomes uniform in order to obtain a magnet that is more uniform and has a higher magnetic field in applications such as MRI and NMR. There is a demand for uniform current density. Metal-based superconducting wires such as NbTi have a degree of freedom in shapes such as round wires and flat wires, and are manufactured through a wire drawing process, so that the tolerance of the thickness of the wires is about a few tens of μm. It is possible. In contrast, yttrium (Y) -based oxide high-temperature superconducting wires have a structure in which thin layers are stacked in layers on a metal substrate, and bismuth (Bi) -based oxide high-temperature superconducting wires are filaments as stabilizing materials. It has a multi-core structure in which a large number of the superconductors are embedded, and the tolerance of the wire thickness greatly exceeds 100 μm. Thus, when manufacturing a magnet having a uniform and high magnetic field using a high-temperature superconducting wire that is difficult to manufacture with accurate wire dimensions, it is a problem to manage the winding accuracy.

  The present invention has been made in view of the above circumstances, and manufacture of a superconducting coil capable of easily manufacturing a superconducting coil in which the superconducting wire is uniformly wound even if the thickness tolerance of the superconducting wire is large. It is an object to provide a method and a manufacturing apparatus.

In order to solve the above-mentioned problems, the present invention provides a method of manufacturing a superconducting coil wound with a tape-shaped superconducting wire, the step of adjusting the thickness of the superconducting wire before winding the superconducting wire, and the superconducting Measuring the outer circumference of the superconducting coil during winding with an optical transmission sensor while winding the wire, and measuring the thickness in the longitudinal direction of the superconducting wire in advance, based on this thickness information And providing a method of manufacturing a superconducting coil, wherein the thickness of the superconducting wire is adjusted.
The outer peripheral dimension of the superconducting coil is preferably the outer diameter of the superconducting coil.
The superconducting wire may have an oxide superconducting layer made of an yttrium-based oxide superconductor.

In order to solve the above-mentioned problem, the present invention provides a superconducting coil manufacturing apparatus in which a tape-shaped superconducting wire is wound, and a winding unit for winding the superconducting wire, and the superconducting wire in the winding unit. A thickness adjusting unit that adjusts the thickness of the superconducting wire before winding, an optical transmission sensor that measures the outer circumference of the superconducting coil during winding while winding the superconducting wire with the winding unit, and A control unit that records the thickness information obtained by measuring the thickness over the longitudinal direction of the superconducting wire, transmits a signal based on the thickness information to the thickness adjusting unit, and adjusts the thickness of the superconducting wire; A superconducting coil manufacturing apparatus is provided.
The outer peripheral dimension of the superconducting coil is preferably the outer diameter of the superconducting coil.
The superconducting wire may have an oxide superconducting layer made of an yttrium-based oxide superconductor.

  According to the present invention, by measuring the outer peripheral dimension of the superconducting coil at the time of winding using an optical transmission sensor, the variation in the thickness of the superconducting wire is obtained based on the outer peripheral dimension of the superconducting coil with high accuracy without contact. be able to. Further, by adjusting the thickness of the superconducting wire, it is possible to reduce the variation in the thickness of the superconducting wire and to manufacture a superconducting coil in which the superconducting wire is uniformly wound.

It is a schematic block diagram which shows the Example of the manufacturing apparatus using an optical transmissive sensor. It is explanatory drawing which shows an example of the positional information on a coil circumferential direction. It is a schematic block diagram which shows the contrast of the manufacturing apparatus using an optical reflection type sensor.

Hereinafter, based on a preferred embodiment, the present invention will be described with reference to the drawings.
FIG. 1 shows an embodiment of a manufacturing apparatus using an optical transmission sensor. The manufacturing apparatus 10 includes a sending unit 11 that sends out the superconducting wire 12, a winding unit 15 that winds up the superconducting wire 12, a thickness adjusting unit 19 that adjusts the thickness of the superconducting wire 12, and the outer periphery of the superconducting coil 13 during winding. The optical transmission type sensor 20 etc. which measure a dimension are provided.

The superconducting wire 12 has a multilayer composite structure having a metal substrate, a superconducting layer, a protective layer, a stabilizing layer, and the like. As an example, a structure in which an underlayer, an orientation intermediate layer, a cap layer, an oxide superconducting layer, a protective layer, and a stabilization layer are sequentially stacked on a metal substrate can be given. The metal substrate is a tape-shaped substrate made of a metal such as a nickel alloy. The underlayer is made of, for example, Y ₂ O ₃ and has high heat resistance and is provided to reduce interface reactivity.

A diffusion prevention layer such as Al ₂ O ₃ may be interposed between the metal substrate and the base layer. The orientation intermediate layer is made of a metal oxide such as Gd ₂ Zr ₂ O ₇ , MgO, ZrO ₂ —Y ₂ O ₃ (YSZ), or SrTiO ₃ and is selected from materials that are biaxially oriented. The cap _{layer, CeO 2, Y 2 O 3} , Al 2 O 3, Gd 2 O 3, Zr 2 O 3, Ho 2 O 3, Nd 2 O 3 , etc., those crystal grains are selectively grown in the in-plane direction preferable.

The superconducting layer is made of an oxide superconductor such as RE123 (REBa ₂ Cu ₃ O _7-δ ). RE in RE123 represents a rare earth element such as Y, La, Nd, Sm, Er, or Gd. Examples of RE123 include Y123 (YBa ₂ Cu ₃ O _7-δ ) or Gd123 (GdBa ₂ Cu ₃ O _7-δ ). The protective layer is made of Ag, a noble metal, or the like. The stabilization layer is preferably made of a highly conductive metal material such as copper or a copper alloy such as brass (Cu—Zn alloy).

As another example of the superconducting wire 12, and a _{Bi2212 (Bi 2 Sr 2 CaCu 2} O 8 + δ), Bi2223 (Bi 2 Sr 2 Ca 2 Cu 3 O 10 + δ) bismuth using bismuth-based superconductors such as superconducting wires . The bismuth-based superconducting wire mainly has a structure in which an oxide superconducting layer is included in a sheath made of a tape-like stabilizing material such as Ag.

  The tape-shaped superconducting wire 12 is sent out from the sending unit 11 toward the winding unit 15 in the unwound state. The thickness adjusting unit 19 adjusts the thickness of the superconducting wire 12 by increasing or decreasing the thickness of the superconducting wire 12. When the thickness of the superconducting wire 12 is increased, a method of supplying an insulating member interposed between the superconducting wires in the superconducting coil 13 can be mentioned. As a method for supplying the insulating member, there is a method of stacking a tape-like insulating material such as polyimide tape or FRP (fiber reinforced plastic) tape, or applying a liquid resin such as epoxy. When reducing the thickness of the superconducting wire 12, a method of removing a part of the resin in the thickness adjusting unit 19 after laminating a resin or the like on the superconducting wire 12 in front of the thickness adjusting unit 19 can be mentioned.

  The superconducting wire 12 that has passed through the thickness adjusting unit 19 is wound around a winding frame 14 such as a bobbin or a reel at a winding unit 15 to form a superconducting coil 13. The structure of the reel 14 is not particularly limited. For example, the material of the reel 14 may be a structure having a flange having a diameter larger than that of the barrel on both sides of the cylindrical barrel. (Glass fiber reinforced plastic) is preferable. The winding unit 15 may include a motor (not shown) or the like in order to rotationally drive the winding frame 14.

  In the present invention, in order to manage the accuracy of adjusting the thickness of the superconducting wire, the outer peripheral dimension of the superconducting coil during winding is measured by an optical transmission sensor. As shown in FIG. 1, the optical transmission sensor 20 includes a transmitter 21 that transmits the measurement light 23 and a receiver 22 that receives the measurement light 23. A laser is used as measurement light. The winding frame 14 of the winding unit 15 is disposed between the transmission unit 21 and the reception unit 22. In the winding unit 15, the superconducting coil 13 is formed by winding the superconducting wire 12 around the winding frame 14. The transmitter 21 transmits the measurement light 23 toward the superconducting coil 13 in the winding. The receiving unit 22 recognizes the range in which the measurement light 23 is transmitted around the superconducting coil 13 and the range in which the measurement light 23 is blocked by hitting the superconducting coil 13, and determines the boundary position between the transmitted range and the blocked range. The outer circumference of the superconducting coil 13 is detected. Here, the outer peripheral dimension of the coil is the length of a section in which at least one end of the dimension is on the outer periphery of the superconducting coil, and the fluctuation of the thickness of the superconducting wire is obtained using the fluctuation information of the outer peripheral dimension of the coil. If it is possible, there is no particular limitation. The calculation for obtaining the variation in the thickness of the superconducting wire need not be based only on the variation in the outer peripheral dimension of the coil, and other information such as the dimension and position of the winding frame can be used together. The outer peripheral dimension may be the outer diameter (diameter) of the superconducting coil 13, may be the thickness from the outer peripheral surface of the winding frame 14 to the outer periphery of the superconducting coil 13, or from the center of the winding frame 14 to the superconducting coil. The distance to the outer periphery of 13 (namely, coil radius) may be sufficient, and other dimensions may be sufficient. Examples of the boundary position that can be recognized by the optical transmission sensor 20 include the boundary between the outer periphery of the superconducting coil 13 and the external atmosphere (air), and the boundary between the inner periphery of the superconducting coil 13 and the outer periphery of the winding frame 14. It is also possible to provide a structure such as a mark that can be recognized by the optical transmission sensor 20 at a specific position of the reel 14 (for example, the central axis of the reel 14). By using the optical transmission type sensor, even if the superconducting coil 13 is a large superconducting coil having an outer diameter of more than 80 mm, the outer peripheral dimensions can be managed with high accuracy of ± 8 μm or less. When measuring the thickness from the outer peripheral surface of the winding frame 14 to the outer periphery of the superconducting coil 13, only one side of the coil has to be placed in the measurement area of the optical transmission sensor 20, so that it can be applied to a coil having a larger outer diameter. Easy. When measuring the outer diameter (diameter) of the superconducting coil 13, since both ends of the dimension are on the outer periphery of the superconducting coil, it is possible to measure only by recognizing the boundary between the outer periphery of the superconducting coil and the external atmosphere (air). .

  As a comparative example, an example of a manufacturing apparatus using an optical reflection sensor is shown in FIG. Similar to the manufacturing apparatus 10 of the embodiment, the manufacturing apparatus 30 also includes a delivery unit 31 and a winding unit 35 for the superconducting wire 32. In the comparative manufacturing apparatus 30, the outer peripheral dimension of the superconducting coil 33 on the winding frame 34 is measured by the optical reflection sensor 37 during winding. The optical reflection type sensor 37 can measure the position and size of the object according to the time until the measurement light 36 is reflected and returned. However, adjustment of the laser incident position is necessary to adjust the reflection position, and the measurement accuracy is about ± 20 μm when the coil outer diameter is 80 μm or less. In addition, when manufacturing a coil with a large outer diameter and a coil with a small outer diameter using the same manufacturing apparatus, it is necessary to change the distance from the optical reflection sensor 37 to the winding frame 34 according to the coil outer diameter. Measures such as switching on the way are necessary.

  However, in the case of the manufacturing apparatus of the embodiment, by using an optical transmission sensor, it is possible to measure the outer peripheral dimension of the coil having an outer diameter of more than 80 mm, and one sensor can be applied to various coil outer diameters. Further, the accuracy of the measured value can be ± 8 μm or less.

  In order to convert the change in the outer peripheral dimension of the coil into the thickness of the superconducting wire, the change in the outer peripheral dimension is interlocked with the rotation speed of the reel, and the change in thickness at the same position on the reel is changed every turn, or Calculate every half turn. For this reason, in the manufacturing apparatus 10 of FIG. 1, the control part 16 which calculates information and controls the thickness adjustment part 19, the display part 17 which displays information from the control part 16 as needed, and the reel 14 A position sensor unit 18 for measuring a circumferential position is provided. As the control unit 16, for example, a control device such as a PLC (programmable logic controller) or a computer can be used.

  The position sensor unit 18 measures position information in the circumferential direction of the coil. As position information, for example, a point for measuring the position by the position sensor unit 18 is set in the circumferential direction of the winding frame 14 in the winding unit 15. FIG. 2 shows an example in which 8 points are set every 45 °, such as 0 °, 45 °, 90 °, 135 °, 180 °, 225 °, 270 °, and 315 °. However, the present invention is not limited to this. Absent. By calculating the position information in the control unit, it can serve as a counter for measuring the runout of the reel and variations in the shape of the reel, and as a counter for measuring the length of the wound superconducting wire. .

(1) Before winding, with the empty winding frame 14 attached to the winding unit 15, the winding frame 14 is rotated, and the outer peripheral dimension A _{x = 0} (w °) at each point is measured. Let me record. x represents the number of turns of the superconducting wire, and x = 0 represents that the superconducting wire is not wound. For example, when the outer peripheral dimension represents the outer diameter (diameter) of the coil, A _{x = 0} (w °) means the outer diameter (diameter) of the body portion of the winding frame.

(2) During winding, the outer peripheral dimension Ax (w °) of the superconducting coil 13 at each point is measured. The controller 16 calculates the total thickness Bx (w °) of the superconducting wire wound around the coil by calculating Ax (w °) −A _{x = 0} (w °). Further, the length of the wound wire is calculated from the coil outer dimension and the number of turns.

(3) For the number of turns × design value (thickness per turn) = Bx _design , the controller 16 calculates the excess / deficiency of Bx (w °) and sends information to the thickness adjuster 19. send. Information can also be sent from the control unit 16 to the display unit 17 and displayed on the display unit 17 for the operator.

(4) The thickness is adjusted by the thickness adjusting unit 19 so as to match Bx _design . When the increase in thickness is insufficient in the winding unit 15, the thickness adjustment unit 19 performs adjustment so that the thickness of the superconducting wire 12 becomes larger. When the increase in the thickness is excessive in the winding unit 15, the thickness adjustment unit 19 is adjusted so as to suppress the increase in the thickness of the superconducting wire 12 or to decrease the thickness.

  The thickness adjustment of the superconducting wire 12 by the thickness adjusting unit 19 is performed at a position different from the position at which the outer circumference dimension of the coil is measured by the optical transmission sensor 20, so that the time difference of the thickness adjustment is determined according to these positional relationships It is preferable to set. When the variation of the thickness along the longitudinal direction of the superconducting wire 12 is relatively gradual, it is preferable to make the distance in the longitudinal direction from the thickness adjusting unit 19 to the optical transmission sensor 20 as small as possible.

  When the variation (increase / decrease) in thickness along the longitudinal direction of the superconducting wire 12 is relatively severe, a thick wire is placed on the thin wire on the outer periphery of the coil, and a thick wire In order to superimpose thin wire rods on top, it is preferable to control so that, for example, a time difference of one round of the coil occurs.

  When adjusting the thickness of the insulator attached to the wire of the superconducting wire 12 in the thickness adjusting unit 19, the insulator attached portion is on the front side (outside in the radial direction of the coil) or back side (inside in the radial direction of the coil) of the wire. Or one side of the wire.

  As mentioned above, although this invention has been demonstrated based on suitable embodiment, this invention is not limited to the above-mentioned embodiment, A various change is possible in the range which does not deviate from the summary of this invention.

  In FIG. 1, based on the coil outer circumference dimension after winding, the variation of the thickness of the superconducting wire is calculated and fed back to the adjustment of the thickness of the superconducting wire. However, the present invention is not limited to this configuration. Absent. The thickness of the superconducting wire is measured in advance along the longitudinal direction of the superconducting wire, the thickness information is recorded in the control unit, and a signal based on the thickness information is transmitted to the thickness adjusting unit during winding. It is also possible to adjust. In this case, the measurement of the outer periphery dimension of the coil by the optical transmission sensor serves to confirm the outer periphery dimension of the coil and to measure the length of the wound superconducting wire.

When the outer peripheral dimension Ax (w) measured by the optical transmission sensor is the outer diameter (diameter) of the single pancake coil, the outer diameter of the coil corresponds to the diameter of the superconducting wire at the outermost periphery of the coil. The thickness of the superconducting wire increases by two. Therefore, in order to obtain the thickness of one recently wound superconducting wire at a certain point w (°), the outer diameter of the coil before the half circumference may be subtracted from the outer diameter of the coil at that point. When 0 ° ≦ w <180 °, the value is Ax (w) −A _x−1 (w + 180 °), and when 180 ° ≦ w <360 °, Ax (w) −Ax (w−180 ° ), The thickness of one superconducting wire can be obtained. In this case, it is preferable to set an even number of points at equal intervals with respect to one round.

  The present invention is also applicable to double pancake coils and solenoid coils. When applied to a double pancake coil, it is also possible to measure the outer circumference of the coil with an optical transmission sensor for the upper and lower two-stage coils.

  As a post-treatment of the wound coil, the periphery may be covered with an insulating material such as resin or impregnated with resin. It is also possible to connect a plurality of coils and stack them in the axial direction.

DESCRIPTION OF SYMBOLS 10,30 ... Manufacturing apparatus, 11, 31 ... Sending part, 12, 32 ... Superconducting wire, 13, 33 ... Superconducting coil, 14, 34 ... Winding frame, 15, 35 ... Winding part, 16 ... Control part, 17 ... Display part 18 ... Position sensor part 19 ... Thickness adjustment part 20 ... Optical transmission type sensor 21 ... Transmission part 22 ... Reception part 23, 36 ... Measuring light 37 ... Optical reflection type sensor

Claims (6)

A method of manufacturing a superconducting coil wound with a tape-shaped superconducting wire,
Adjusting the thickness of the superconducting wire before winding the superconducting wire;
Measuring the outer peripheral dimension of the superconducting coil during winding while winding the superconducting wire with an optical transmission sensor;
A method of manufacturing a superconducting coil, comprising: measuring a thickness of the superconducting wire in a longitudinal direction in advance, and adjusting the thickness of the superconducting wire based on the thickness information.   The method for manufacturing a superconducting coil according to claim 1, wherein an outer peripheral dimension of the superconducting coil is an outer diameter of the superconducting coil.   The method for manufacturing a superconducting coil according to claim 1 or 2, wherein the superconducting wire has an oxide superconducting layer made of an yttrium-based oxide superconductor. A superconducting coil manufacturing apparatus in which a tape-shaped superconducting wire is wound,
A winding unit for winding the superconducting wire;
A thickness adjusting unit for adjusting the thickness of the superconducting wire before winding the superconducting wire with the winding unit;
An optical transmission sensor that measures the outer peripheral dimensions of the superconducting coil during winding while winding the superconducting wire at the winding unit;
A control unit that records thickness information measured in advance in the longitudinal direction of the superconducting wire, and transmits a signal based on the thickness information to the thickness adjusting unit to adjust the thickness of the superconducting wire. When,
A superconducting coil manufacturing apparatus characterized by comprising:   The apparatus for manufacturing a superconducting coil according to claim 4, wherein the outer peripheral dimension of the superconducting coil is an outer diameter of the superconducting coil.   6. The superconducting coil manufacturing apparatus according to claim 4, wherein the superconducting wire has an oxide superconducting layer made of an yttrium-based oxide superconductor.

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