Superconducting coil capable of adjusting pretightening force and manufacturing method thereof

Abstract

The invention provides a superconducting coil capable of adjusting pretightening force and a manufacturing method thereof, and belongs to the field of superconducting coils. The superconducting coil capable of adjusting the pretightening force comprises a superconducting coil body, a coil framework, an upper flange, a lower flange, a heat insulation buffer layer, a first reinforcing ring, a first reinforcing ring supplement block, a second reinforcing ring, a second reinforcing ring supplement block, a third reinforcing ring, a third reinforcing ring supplement block, a first binding layer, a second binding layer and a third binding layer. The high-strength aluminum alloy reinforcing ring is adopted to bind the outer layer of the superconducting coil, the annular electromagnetic force and the axial electromagnetic force of the superconducting coil can be well restrained, the overall strength of the superconducting coil is improved, and the structure buckling risk caused by the axial force in the excitation process is reduced. By utilizing the difference between the thermal expansion coefficients of the aluminum alloy material of the reinforcing ring and the superconducting coil, the pre-tightening force on the superconducting coil is increased after cooling, and different pre-tightening force effects can be exerted through different binding layer tension.

Description

Technical Field

[0001] This invention belongs to the field of superconducting coils, specifically relating to a superconducting coil with adjustable preload and its manufacturing method. Background Technology

[0002] Superconducting magnets are made by winding superconducting wires into coils and then passing an electric current through them at low temperatures to generate a strong magnetic field. Superconducting magnets are increasingly widely used in scientific research devices, including nuclear fusion devices, comprehensive physical property measurement instruments, nuclear magnetic resonance spectrometers, nuclear magnetic resonance imaging, and other scientific applications requiring strong magnetic fields. Solenoid superconducting magnets are one of the most common types of superconducting magnets. Due to their axisymmetric structure, they simplify design models during electromagnetic design and manufacturing, and offer greater engineering feasibility.

[0003] However, during the application of superconducting magnets, due to the large current they carry, a significant Lorentz force is generated inside the magnet. Under the influence of this massive Lorentz force, the superconductors inside the magnet tend to move relative to each other, resulting in minute relative displacements. During this relative displacement, two adjacent superconductors rub against each other, generating heat. If this heat is not promptly conducted to a cooling source, it will accumulate locally. Even small amounts of heat can cause a localized temperature rise, eventually raising the superconductor's temperature above its critical temperature, thus triggering the magnet's quenching failure.

[0004] In the manufacturing process of superconducting magnets, preload is often applied to ensure that superconducting wires are tightly packed, reducing the gaps between them and thus minimizing the free space within the superconducting coil, thereby suppressing relative movement of the wires. Furthermore, since the critical current capacity of a superconducting wire is directly related to the stress and strain applied to it, the critical current decreases rapidly with increasing stress and strain. When the stress and strain reach a certain level, the current-carrying capacity of the superconducting wire will no longer recover as the strain decreases. Once the applied strain exceeds this reversible limit, the superconducting performance will undergo irreversible degradation, and even if the external force is removed, the current-carrying capacity cannot return to its initial value. Therefore, in the design and manufacturing of superconducting magnets, the stress and strain of the superconducting wires must not be too large; they must be controlled within a very small range to ensure a reversible relationship between current and stress / strain.

[0005] To suppress strain in the internal conductors of a superconducting magnet, a protective layer needs to be placed around the magnet to resist the expansion and deformation of the internal superconducting magnet during energization. However, because the superconducting magnet operates under extreme conditions, subjected to the multi-field coupling effects of extremely low temperatures, high currents, and high magnetic fields, it is difficult to accurately assess the stress state on the superconductor inside the magnet. Furthermore, when the superconducting magnet operates at a large current, the materials are already under extreme stress. Therefore, it is necessary to increase the safety margin and safety factor of the superconducting magnet as much as possible to improve its operational stability. Summary of the Invention

[0006] To overcome the problem that existing superconducting coil reinforcement methods cannot provide sufficient axial support, leading to structural buckling of the superconducting coil and subsequent quench loss during excitation due to insufficient axial force, and to address the issues of wire binding loosening at low temperatures due to differences in thermal expansion coefficients, resulting in reduced binding force on the superconducting coil, and the uniform axial binding force of existing binding layers that cannot be adjusted according to the magnet structure, this invention provides a superconducting coil with adjustable preload and its manufacturing method. A high-strength aluminum alloy reinforcing ring is used for the outer layer of the superconducting coil. Binding effectively constrains the circumferential and axial electromagnetic forces of the superconducting coil, increasing its overall strength and reducing the risk of structural buckling caused by axial forces during excitation. Utilizing the difference in thermal expansion coefficients between the aluminum alloy material of the reinforcing ring and the superconducting coil, the preload on the coil increases after cooling. Furthermore, the preload on the reinforcing ring can be segmented axially according to the stress on the superconducting coil, increasing the thickness of the reinforcing ring near the mid-plane to enhance the preload at the mid-plane and resist greater stress and strain on the superconductor near the mid-plane. Different preload effects can be applied through varying binding layer tensions.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] An adjustable preload superconducting coil includes a coil frame, a superconducting coil, a heat insulation buffer layer, a reinforcing ring, a reinforcing ring supplement block, and a binding layer. The superconducting coil is wound on the coil frame, the heat insulation buffer layer covers the outer circumference of the superconducting coil, the reinforcing ring is sleeved on the outside of the heat insulation buffer layer, the reinforcing ring has an opening, the reinforcing ring supplement block is embedded in the opening of the reinforcing ring and spliced ​​with the reinforcing ring to form a complete ring structure, and the binding layer is wound on the outer circumference of the reinforcing ring. The binding layer transmits radial preload to the superconducting coil through the reinforcing ring.

[0009] Furthermore, the reinforcing ring includes a first reinforcing ring, a second reinforcing ring, and a third reinforcing ring; the reinforcing ring supplement block includes a first reinforcing ring supplement block, a second reinforcing ring supplement block, and a third reinforcing ring supplement block; the binding layer includes a first binding layer, a second binding layer, and a third binding layer; and the first reinforcing ring supplement block, the second reinforcing ring supplement block, and the third reinforcing ring supplement block are respectively embedded in the openings of the first reinforcing ring, the second reinforcing ring, and the third reinforcing ring.

[0010] Furthermore, the first reinforcing ring, the second reinforcing ring, and the third reinforcing ring are all made of high-strength aluminum alloy.

[0011] Furthermore, the first binding layer, the second binding layer, and the third binding layer are all made of high-strength steel wire.

[0012] Furthermore, the third reinforcing ring is fitted below the mid-plane of the superconducting coil, the first reinforcing ring is fitted at the mid-plane of the superconducting coil, and the second reinforcing ring is fitted above the mid-plane of the superconducting coil. The total height of the first, second, and third reinforcing rings spliced ​​together along the axial direction is equal to the height of the superconducting coil.

[0013] Furthermore, the outer diameter of the first reinforcing ring is larger than the outer diameters of the second and third reinforcing rings.

[0014] Furthermore, the winding tension of the first binding layer is greater than the winding tension of the second binding layer and the winding tension of the third binding layer.

[0015] Furthermore, the heat insulation buffer layer is made of high-temperature resistant fiberglass cloth, which insulates against the high temperature generated during the welding of the reinforcing ring and buffers the pressure applied by the binding layer.

[0016] Furthermore, the inner diameter of the reinforcing ring is larger than the outer diameter of the superconducting coil.

[0017] The present invention also provides a method for manufacturing the above-mentioned superconducting coil with adjustable preload, comprising the following steps:

[0018] The superconducting coil is wound on a coil frame;

[0019] A heat-insulating buffer layer is wound around the outside of the superconducting coil;

[0020] The superconducting coil is cooled to cause it to shrink.

[0021] Insert the third reinforcing ring into the position below the mid-plane of the superconducting coil, and embed the supplementary block of the third reinforcing ring into the opening of the third reinforcing ring;

[0022] Insert the first reinforcing ring into the mid-plane position of the superconducting coil, and embed the supplementary block of the first reinforcing ring into the opening of the first reinforcing ring;

[0023] Insert the second reinforcing ring into the superconducting coil above the mid-plane, and insert the supplementary block of the second reinforcing ring into the opening of the second reinforcing ring;

[0024] A first binding layer is wound around the outer circumference of the first reinforcing ring, a second binding layer is wound around the outer circumference of the second reinforcing ring, and a third binding layer is wound around the outer circumference of the third reinforcing ring.

[0025] The first reinforcing ring and the first reinforcing ring supplementary block, the second reinforcing ring and the second reinforcing ring supplementary block, and the third reinforcing ring and the third reinforcing ring supplementary block are welded and fixed respectively;

[0026] Remove the first binding layer, the second binding layer and the third binding layer, and complete the welding of the remaining welds between the first reinforcing ring and the first supplementary block, the second reinforcing ring and the second supplementary block, and the third reinforcing ring and the third supplementary block.

[0027] Beneficial effects:

[0028] During the cooling and energizing process of a superconducting coil, the superconducting wire is subjected to electromagnetic forces. Due to the unique axisymmetric structure of the solenoid superconductor, these electromagnetic forces are divided into radial, axial, and circumferential forces. The radial and axial forces are relatively smaller than the circumferential forces. In superconducting coil design, preload and outer binding are often used to constrain the larger circumferential forces. Brass or stainless steel wire is commonly used for outer binding of the superconducting coil, which can significantly reduce the circumferential forces on the superconducting wire. However, during operation, the superconducting coil undergoes a cooling process, generating significant thermal stress on the superconducting wire. Furthermore, assembly errors during magnet assembly can cause asymmetry between the superconducting coil's structure and the magnetic field, both of which generate axial forces. Axial forces are the primary factor causing buckling deformation of the coil structure. Traditional wire binding methods cannot effectively constrain axial forces. When the superconducting coil is energized to high current and high magnetic field, the structural stability of the coil is crucial; even small axial force disturbances can cause the coil to lose quench.

[0029] Based on this, the present invention uses an aluminum alloy reinforcing ring to bind the outer layer of the superconducting coil, which can effectively constrain the circumferential and axial electromagnetic forces of the superconducting coil, increase the overall strength of the superconducting coil, and reduce the risk of structural buckling caused by axial forces during excitation. Since the reinforcing ring itself does not have radial preload, the present invention uses high-strength metal wire wound around the outside of the reinforcing ring for binding, and transmits radial preload to the inside of the superconducting coil through the reinforcing ring. Then, the reinforcing ring is welded into shape to maintain radial preload deformation. At the same time, during the subsequent cooling process of the superconducting coil, the thermal expansion coefficient of aluminum alloy is higher than that of the superconducting coil, resulting in thermal contraction deformation, which continues to apply radial preload to the superconducting coil, reducing the circumferential stress and circumferential strain of the superconducting wire. In addition, due to the magnetic field configuration of the solenoid coil, the maximum circumferential stress and circumferential strain will be generated at the mid-plane of the superconducting coil, thereby transferring the stress to the reinforcing ring at the mid-plane, resulting in the maximum deformation at the first reinforcing ring. This invention, by using reinforcing rings of varying thicknesses, can segmentally constrain the electromagnetic force of the superconducting coil. Placing a thicker reinforcing ring at the location of maximum stress and strain provides superior reinforcement. Furthermore, applying greater tension when winding the binding layer on the outer side of the mid-plane reinforcing ring allows for a greater preload on the superconducting wire. Ultimately, this improves the high-field stability of the superconducting coil and reduces the number of quench failures caused by relative motion of the superconducting wire.

[0030] This invention employs an aluminum alloy reinforcing ring to bind the outer layer of a superconducting coil. This binding provides stability to the coil through the pre-tightening force of the outer binding layer, preventing the binding layer from loosening and reducing its effectiveness during cooling due to the different thermal expansion coefficients of the superconducting coil and traditional stainless steel wire binding. The reinforcing ring of this invention is formed by welding after the outer layer is pre-tightened, effectively fixing the pre-tightening force. Furthermore, the high shrinkage rate of the aluminum alloy further enhances the pre-tightening effect during cooling.

[0031] The device of this invention has a simple structure. It reinforces and protects the superconducting coil using an aluminum alloy reinforcing ring with a high coefficient of thermal expansion. Taking into account the varying electromagnetic forces at different locations within the superconducting coil, the binding layer on the outer side of the reinforcing ring individually restricts the electromagnetic forces within the ultra-thin coil. Furthermore, after pre-tightening, the ring is welded into a single integrated structure, increasing axial strength and reducing the risk of buckling in the superconducting coil structure. Compared to traditional non-adjustable outer metal wire binding, this invention maintains high circumferential strength while increasing axial strength, offering significant advantages. Moreover, this invention is low-cost and suitable for mass industrial manufacturing.

[0032] In summary, this invention uses aluminum alloy reinforcing rings of different thicknesses. Through the combined effect of different binding forces of the first binding layer, the second binding layer, and the third binding layer, the axial strength of the superconducting coil is increased and the high circumferential strength is maintained. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the superconducting coil skeleton of the present invention;

[0034] Figure 2 This is a schematic diagram of the winding superconducting coil and the heat insulation buffer layer of the present invention;

[0035] Figure 3 This is a schematic diagram of the first reinforcing ring and the first reinforcing ring supplementary block of the present invention;

[0036] Figure 4 This is a schematic diagram of the second reinforcing ring and the second reinforcing ring supplement block of the present invention;

[0037] Figure 5 This is a schematic diagram showing the relative positions of the reinforcing ring and the reinforcing ring supplement block of the present invention;

[0038] Figure 6 This is a schematic diagram showing the relative positions of the components before the superconducting coil of the present invention is bound;

[0039] Figure 7 This is a schematic diagram showing the relative positions of the components after the superconducting coil of the present invention is bound.

[0040] The attached figures are labeled as follows: coil frame 1, upper flange 2, lower flange 3, superconducting coil 4, heat insulation buffer layer 5, first reinforcing ring 6, first reinforcing ring supplement block 7, second reinforcing ring 8, second reinforcing ring supplement block 9, third reinforcing ring 10, third reinforcing ring supplement block 11, first binding layer 12, second binding layer 13, and third binding layer 14. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0042] like Figures 1-7As shown, the superconducting coil with adjustable preload of the present invention includes a coil frame 1, an upper flange 2, a lower flange 3, a superconducting coil 4, a heat insulation buffer layer 5, a first reinforcing ring 6, a first reinforcing ring supplement block 7, a second reinforcing ring 8, a second reinforcing ring supplement block 9, a third reinforcing ring 10, a third reinforcing ring supplement block 11, a first binding layer 12, a second binding layer 13, and a third binding layer 14.

[0043] The upper flange 2 and lower flange 3 are connected to both ends of the coil frame 1. The superconducting coil 4 is wound between the upper flange 2 and lower flange 3 of the coil frame 1. A heat-insulating buffer layer 5 is provided on the outside of the superconducting coil 4, flush with the outer surface of the upper flange 2. The heat-insulating buffer layer 5 is concentrically arranged with the superconducting coil 4 and is at the same height.

[0044] The first reinforcing ring 6, the second reinforcing ring 8, and the third reinforcing ring 10 are disposed on the outer side of the heat insulation buffer layer 5, and are all circular rings with openings. The first reinforcing ring 6 is located between the second reinforcing ring 8 and the third reinforcing ring 10, which are located at the upper and lower parts of the superconducting coil 4, respectively, with an inner diameter larger than the outer diameter of the superconducting coil 4. The first reinforcing ring 6 and the first reinforcing ring supplementary block 7 can be spliced ​​into a complete circular ring; the second reinforcing ring 8 and the second reinforcing ring supplementary block 9 can be spliced ​​into a complete circular ring; and the third reinforcing ring 10 and the third reinforcing ring supplementary block 11 can be spliced ​​into a complete circular ring. The first binding layer 12 is located outside the first reinforcing ring 6; the second binding layer 13 is located outside the second reinforcing ring 8; and the third binding layer 14 is located outside the third reinforcing ring 10. The first reinforcing ring 6, the second reinforcing ring 8, and the third reinforcing ring 10 are made of high-strength aluminum alloy. The first binding layer 12, the second binding layer 13, and the third binding layer 14 are all double-looped and made of high-strength steel wire.

[0045] The first reinforcing ring 6 and the first reinforcing ring supplement block 7 are connected to form a complete ring and distributed on the outer mid-plane position of the heat insulation buffer layer 5. The second reinforcing ring 8 and the second reinforcing ring supplement block 9 are connected to form a complete ring and distributed above the outer mid-plane position of the heat insulation buffer layer 5. The third reinforcing ring 10 and the third reinforcing ring supplement block 11 are connected to form a complete ring and distributed below the outer mid-plane position of the heat insulation buffer layer 5. The three complete reinforcing rings are sequentially inserted into the superconducting coil 4, forming a concentric structure with the superconducting coil, and arranged side by side, respectively tightening and binding different positions of the superconducting coil 4.

[0046] Preferably, the first binding layer 12 is bound to the outside of the first reinforcing ring 6 and the first reinforcing ring supplement block 7, the second binding layer 13 is bound to the outside of the second reinforcing ring 8 and the second reinforcing ring supplement block 9, and the third binding layer 14 is bound to the outside of the third reinforcing ring 10 and the third reinforcing ring supplement block 10.

[0047] Furthermore, the superconducting coil 4 is wound on the coil frame 1, the height of the upper flange 2 is flush with the superconducting coil 4 and the heat insulation buffer layer 5, and the height of the lower flange 3 is higher than that of the superconducting coil 4.

[0048] Furthermore, the heat insulation buffer layer 5 is made of high-temperature resistant glass fiber cloth, which can insulate against temperatures above 500°C and block the instantaneous high temperature generated during subsequent welding of the reinforcing ring, effectively protecting the internal superconducting coil.

[0049] Furthermore, the third reinforcing ring 10 is fitted onto the superconducting coil 4 through the upper flange 2 and placed below the mid-plane of the superconducting coil 4, contacting the lower flange 3 of the superconducting coil 4.

[0050] Furthermore, the first reinforcing ring 6 is fitted onto the superconducting coil 4 through the upper flange 2 and placed at the mid-plane position of the superconducting coil 4.

[0051] Furthermore, the second reinforcing ring 8 is fitted onto the superconducting coil 4 through the upper flange 2 and placed above the mid-plane of the superconducting coil 4, in contact with the upper flange 2 of the superconducting coil 4.

[0052] Furthermore, the first reinforcing ring 6, the second reinforcing ring 8, and the third reinforcing ring 10 are spliced ​​together along the axial direction of the superconducting coil, and the height of the spliced ​​ring is equal to the height of the superconducting coil 4.

[0053] Furthermore, the outer diameter of the first reinforcing ring 6 is larger than the outer diameters of the second reinforcing ring 8 and the third reinforcing ring 10. By using reinforcing rings of different thicknesses, this invention can segmentally constrain the electromagnetic force of the superconducting coil. Placing a thicker reinforcing ring at the location of maximum stress and strain provides better reinforcement. Simultaneously, applying greater tension when winding the binding layer on the outer side of the mid-plane reinforcing ring allows for a greater preload on the superconducting wire. Ultimately, this improves the high-field stability of the superconducting coil and reduces the number of quench failures caused by relative motion of the superconducting wire.

[0054] Furthermore, the winding tension of the first binding layer 12 is greater than that of the second binding layer 13. Because the superconducting coil experiences greater force in the middle position, a greater binding force is required for better restraint. To address the different axial forces experienced by the superconducting coil, and the characteristic that the force is greater in the middle and smaller at the ends, different binding forces are provided.

[0055] This invention also provides a method for manufacturing a superconducting coil with adjustable preload, comprising the following steps:

[0056] Step (1) The superconducting coil 4 is wound on the coil frame 1. After the winding is completed, the superconducting coil 4 and the heat insulation buffer layer 5 are flush with the upper flange 2 of the coil frame.

[0057] Step (2) A high-temperature resistant glass fiber cloth is wound around the outside of the superconducting coil 4 as a heat-resistant insulation buffer layer 5. At the same time, it serves to insulate the superconducting coil 4 from the outer reinforcing ring material and to buffer and protect the superconducting wire when the outer binding layer applies pressure inward.

[0058] Step (3) spray liquid nitrogen on the outer layer of the superconducting coil 4 with the heat insulation buffer layer 5 to cool down and shrink the superconducting coil.

[0059] Step (4) Insert the third reinforcing ring 10 onto the superconducting coil 4 through the upper flange 2, placing it below the mid-plane of the superconducting coil 4 and in contact with the lower flange 3 of the superconducting coil 4. Fill the opening gap of the third reinforcing ring 10 with the third reinforcing ring supplement block 11.

[0060] Step (5) Insert the first reinforcing ring 6 onto the superconducting coil 4 through the upper flange 2 and place it at the mid-plane position of the superconducting coil 4. Fill the opening gap of the first reinforcing ring 6 with the first reinforcing ring supplement block 7.

[0061] Step (6) Insert the second reinforcing ring 8 onto the superconducting coil 4 through the upper flange 2, placing it above the mid-plane of the superconducting coil 4 and in contact with the upper flange 2 of the superconducting coil. Fill the opening gap of the second reinforcing ring 8 with the supplementary block 9 of the second reinforcing ring.

[0062] Step (7) Wrap the third binding layer 14 around the upper and lower parts of the third reinforcing ring 10, the first binding layer 12 around the upper and lower parts of the first reinforcing ring 6, and the second binding layer 13 around the upper and lower parts of the second reinforcing ring 8.

[0063] After the winding is completed in step (8), the third reinforcing ring 10 and the third reinforcing ring supplement block 11, the first reinforcing ring 6 and the first reinforcing ring supplement block 7, and the second reinforcing ring 8 and the second reinforcing ring supplement block 9 are welded together by argon arc welding.

[0064] Step (9) Remove the first binding layer 12, the second binding layer 13 and the third binding layer 14, and weld the remaining welds between the third reinforcing ring 10 and the third reinforcing ring supplementary block 11, the first reinforcing ring 6 and the first reinforcing ring supplementary block 7, and the second reinforcing ring 8 and the second reinforcing ring supplementary block 9 using argon arc welding.

[0065] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A superconducting coil with adjustable preload, characterized in that, The device includes a coil frame, a superconducting coil, a heat insulation buffer layer, a reinforcing ring, a reinforcing ring supplement block, and a binding layer. The superconducting coil is wound on the coil frame, the heat insulation buffer layer covers the outer circumference of the superconducting coil, the reinforcing ring is sleeved on the outside of the heat insulation buffer layer, the reinforcing ring has an opening, the reinforcing ring supplement block is embedded in the opening of the reinforcing ring and spliced ​​with the reinforcing ring to form a complete ring structure, and the binding layer is wound on the outer circumference of the reinforcing ring. The binding layer transmits radial preload to the superconducting coil through the reinforcing ring.

2. The superconducting coil with adjustable preload according to claim 1, characterized in that, The reinforcing ring includes a first reinforcing ring, a second reinforcing ring, and a third reinforcing ring. The reinforcing ring supplement block includes a first reinforcing ring supplement block, a second reinforcing ring supplement block, and a third reinforcing ring supplement block. The binding layer includes a first binding layer, a second binding layer, and a third binding layer. The first reinforcing ring supplement block, the second reinforcing ring supplement block, and the third reinforcing ring supplement block are respectively embedded in the openings of the first reinforcing ring, the second reinforcing ring, and the third reinforcing ring.

3. The superconducting coil with adjustable preload according to claim 2, characterized in that, The first reinforcing ring, the second reinforcing ring, and the third reinforcing ring are all made of high-strength aluminum alloy.

4. The superconducting coil with adjustable preload according to claim 2, characterized in that, The first binding layer, the second binding layer and the third binding layer are all made of high-strength steel wire.

5. The superconducting coil with adjustable preload according to claim 2, characterized in that, The third reinforcing ring is fitted below the mid-plane of the superconducting coil, the first reinforcing ring is fitted at the mid-plane of the superconducting coil, and the second reinforcing ring is fitted above the mid-plane of the superconducting coil. The total height of the first, second, and third reinforcing rings spliced ​​together along the axial direction is equal to the height of the superconducting coil.

6. The superconducting coil with adjustable preload according to claim 2, characterized in that, The outer diameter of the first reinforcing ring is larger than the outer diameters of the second and third reinforcing rings.

7. The superconducting coil with adjustable preload according to claim 2, characterized in that, The winding tension of the first binding layer is greater than the winding tension of the second binding layer and the winding tension of the third binding layer.

8. The superconducting coil with adjustable preload according to claim 1, characterized in that, The heat insulation buffer layer is made of high-temperature resistant fiberglass cloth. The heat insulation buffer layer isolates the high temperature generated during the welding of the reinforcing ring and buffers the pressure applied by the binding layer.

9. The superconducting coil with adjustable preload according to claim 1, characterized in that, The inner diameter of the reinforcing ring is larger than the outer diameter of the superconducting coil.

10. A method for manufacturing a superconducting coil with adjustable preload as described in any one of claims 1-9, characterized in that, Includes the following steps: The superconducting coil is wound on a coil frame; A heat-insulating buffer layer is wound around the outside of the superconducting coil; The superconducting coil is cooled to cause it to shrink. Insert the third reinforcing ring into the position below the mid-plane of the superconducting coil, and embed the supplementary block of the third reinforcing ring into the opening of the third reinforcing ring; Insert the first reinforcing ring into the mid-plane position of the superconducting coil, and embed the supplementary block of the first reinforcing ring into the opening of the first reinforcing ring; Insert the second reinforcing ring into the superconducting coil above the mid-plane, and insert the supplementary block of the second reinforcing ring into the opening of the second reinforcing ring; A first binding layer is wound around the outer circumference of the first reinforcing ring, a second binding layer is wound around the outer circumference of the second reinforcing ring, and a third binding layer is wound around the outer circumference of the third reinforcing ring. The first reinforcing ring and the first reinforcing ring supplementary block, the second reinforcing ring and the second reinforcing ring supplementary block, and the third reinforcing ring and the third reinforcing ring supplementary block are welded and fixed respectively; Remove the first binding layer, the second binding layer and the third binding layer, and complete the welding of the remaining welds between the first reinforcing ring and the first supplementary block, the second reinforcing ring and the second supplementary block, and the third reinforcing ring and the third supplementary block.

Images