Rotor for superconducting rotating machine and superconducting rotating machine

Abstract

To prevent deterioration of superconducting characteristics and improve the efficiency of magnetic field generation, thereby enhancing the reliability of a superconducting rotating machine.SOLUTION: A rotor 1 for a superconducting rotating machine includes a coil shaft 2 that serves as the axis of a rotor 1 for the rotating machine, a pancake coil 3 for a field winding that is held on the outer surface of the coil shaft 2 and is wound with tape-shaped superconducting wire, and a spacer 4 that is disposed between the pancake coil 3 and the coil shaft 2 and adhered to each of them, and is configured such that dimensions T1 to T4 of the spacer 4 in the direction of the winding axis of the pancake coil 3 are larger on the outer peripheral side of the winding of the pancake coil 3 than on the inner peripheral side of the winding of the pancake coil 3.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] An embodiment of the present invention relates to a rotor for a superconducting rotating electric machine and a superconducting rotating electric machine. [Background technology]

[0002] There is a rotating electric machine in which a tape-shaped RE-based high-temperature superconducting wire is wound into an oval shape (a shape consisting of a straight portion and a circular arc portion connected to this straight portion) to form a coil for a field winding. When this rotating electric machine is in operation, the coil is subjected to centrifugal force. The coil is fixed to a coil shaft that serves as the axis of the rotor. When the inner circumference side of the coil winding is used to connect with the pole piece of the coil shaft, the centrifugal force causes the outer circumference side of the coil winding to deform radially outward. This causes shear stress to be applied between the turns of the coil winding, which poses the risk of peeling off the superconducting layer in the superconducting wire and thus deteriorating the superconducting properties. On the other hand, if a part for suppressing the deformation of the coil is placed on the radial outside of the cross section of the field magnet, the distance between the coil and the armature on the outside of the coil will increase, reducing the efficiency of generating a magnetic field. Therefore, from the viewpoint of avoiding the deterioration of the superconducting properties and the efficiency of generating a magnetic field, it is desired to suppress the deformation of the coil due to the centrifugal force without placing any part on the radial outside of the cross section of the field magnet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5471285 [Patent Document 2] U.S. Pat. No. 1,303,194 Summary of the Invention [Problem to be solved by the invention]

[0004] As mentioned above, when RE-based high-temperature superconducting wire is used for the winding of the rotor of a rotating electric machine, there is a problem that the outer periphery of the coil deforms more outward in the radial direction of the rotor than the inner periphery of the coil due to centrifugal force during operation, which tends to cause deterioration of the superconducting characteristics. In addition, if any parts for suppressing deformation of the coil due to centrifugal force are placed outside the coil, there is a problem that the efficiency of generating a magnetic field decreases.

[0005] The embodiments of the present invention have been made in consideration of the above circumstances, and have an object to prevent deterioration of superconducting characteristics, improve efficiency in generating a magnetic field, and increase the reliability of a superconducting rotating electric machine. [Means for solving the problem]

[0006] A rotor for a superconducting rotating electric machine according to an embodiment of the present invention comprises a coil shaft that serves as the axis of the rotor of the rotating electric machine, a pancake coil for a field winding held on the outer surface of the coil shaft and wound with tape-shaped superconducting wire, and a spacer disposed between the pancake coil and the coil shaft and adhered to each, and is configured such that the dimension of the spacer in the direction of the winding axis of the pancake coil is larger on the outer side of the winding of the pancake coil than on the inner side of the winding of the pancake coil. Effect of the Invention

[0007] According to the embodiments of the present invention, it is possible to prevent deterioration of superconducting characteristics and improve the efficiency of magnetic field generation, thereby improving the reliability of superconducting rotating electric machines. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a perspective view showing a rotor according to the first embodiment. [Diagram 2] 2 is a perspective cross-sectional view showing the rotor of FIG. 1 cut in a plane perpendicular to the rotation axis. [Diagram 3] FIG. 2 is a cross-sectional view showing a rotor cut in a plane perpendicular to the rotation axis. [Figure 4]FIG. 4 is an enlarged cross-sectional view showing a part of the spacer shown in FIG. [Diagram 5] FIG. 4 is a side cross-sectional view showing the rotor cut along the rotation axis. [Figure 6] 6 is an enlarged cross-sectional view showing a part of the spacer shown in FIG. 5; [Figure 7] FIG. [Figure 8] 8 is a cross-sectional view showing the spacer corresponding to the cross section VIII-VIII of FIG. 7. [Figure 9] FIG. 11 is a perspective view showing a rotor according to a second embodiment. [Figure 10] FIG. 11 is a perspective cross-sectional view showing a rotor according to a third embodiment, taken along a rotation axis. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (First embodiment) DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a rotor for a superconducting rotating electric machine and a superconducting rotating electric machine will be described in detail with reference to the drawings. First, a first embodiment will be described with reference to FIGS.

[0010] Reference numeral 1 in Fig. 1 denotes a rotor for a superconducting rotating electric machine according to the first embodiment. This rotor 1 is used in a superconducting rotating electric machine (not shown). The superconducting rotating electric machine configured using the rotor 1 includes devices such as an electric motor (motor) and a generator that are cooled to an operating temperature at which the rotor is in a superconducting state and operate.

[0011] In the following description, the direction in which the rotation axis Z of the rotor 1 extends is referred to as the rotor axial direction (Z direction), the direction extending from the rotation axis Z toward the outer periphery of the rotor 1 is referred to as the rotor radial direction (R direction), and the direction along the outer periphery of the rotor 1 is referred to as the rotor circumferential direction. The rotor circumferential direction is also the direction in which the rotor 1 rotates around the rotation axis Z. The direction in which the winding axis W of the pancake coil 3 extends (parallel to the winding axis W) is referred to as the winding axis direction (W direction). The W direction is almost the same as the R direction. However, the W direction is a direction that perpendicularly penetrates the front and back surfaces of the pancake coil 3 and may not intersect with the rotation axis Z. The R direction is a direction that intersects with the rotation axis Z and may diagonally penetrate the front and back surfaces of the pancake coil 3.

[0012] As shown in FIGS. 1 and 2, the rotor 1 includes a coil shaft 2, a plurality of pancake coils 3, and a plurality of spacers 4.

[0013] The coil shaft 2 is a cylindrical member that serves as the shaft of the rotor 1 of the rotating electric machine. The coil shaft 2 is formed into a circular shape in a cross-sectional view (FIG. 3). Predetermined rotating members (not shown) of the superconducting rotating electric machine are provided inside the coil shaft 2.

[0014] The coil shaft 2 includes a cylindrical portion 20 , two flange portions 21 , and a plurality of pole pieces 22 .

[0015] The two flange portions 21 are provided at one end and the other end of the cylindrical portion 20. These two flange portions 21 are rotatably supported by a member such as a predetermined housing (not shown) of the superconducting rotating electric machine. Alternatively, other members constituting the rotating electric machine are attached to these flange portions 21.

[0016] A plurality of pole pieces 22 are provided on the outer peripheral surface of the cylindrical portion 20. For example, six pole pieces 22 are provided on the outer peripheral surface of the cylindrical portion 20, which is circular in cross section (FIG. 3). These six pole pieces 22 are provided at regular intervals in the circumferential direction of the cylindrical portion 20. These pole pieces 22 are convex parts protruding in the outer radial direction from the cylindrical portion 20. When the coil shaft 2 is viewed from the outer diameter side (in a plan view), these pole pieces 22 form a rectangle extending in the rotor axial direction (Z direction) or an oval shape along the bore portion 32 of the pancake coil 3.

[0017] The multiple pancake coils 3 are superconducting coils for field windings that are held on the outer circumferential surface of the coil shaft 2 and are formed by winding a tape-shaped superconducting wire (not shown) around a winding axis W to form a pancake shape. Here, the direction in which the winding axis W extends is the same as the direction in which the pole pieces 22 protrude. The entire rotor 1 including the pancake coils 3 is cooled by a refrigerator (not shown) or a predetermined refrigerant to a temperature at which the superconducting state can be maintained.

[0018] The pancake coil 3 is wound around the pole piece 22. Alternatively, the pancake coil 3 is separately wound to form an oval shape and then attached to the pole piece 22. For example, the superconducting wire of the pancake coil 3 is wound around six pole pieces 22. These six pancake coils 3 are provided at regular intervals in the circumferential direction of the cylindrical portion 20.

[0019] As shown in Fig. 7, the pancake coil 3 has an oval shape including a straight portion 30 and an arc portion 31 when the coil shaft 2 is viewed from the outer diameter side (in a plan view). The straight portion 30 is a portion where the superconducting wire (not shown) constituting the pancake coil 3 extends linearly. The arc portion 31 is a portion where the superconducting wire is bent into an arc shape. The pancake coil 3 has a substantially flat plate shape in a cross-sectional view (Fig. 8).

[0020] The pancake coil 3 is formed with a bore portion 32 that is open in the center. This bore portion 32 is an opening that extends in the rotor axial direction (Z direction) so as to match the shape of the rectangular pole piece 22. The bore portion 32 is fitted into the pole piece 22. The inner circumference side of the winding of the pancake coil 3 is fixed to the pole piece 22. In other words, the pancake coil 3 is fixed with the bore portion 32 mated with the pole piece 22 of the coil shaft 2.

[0021] 3, a plurality of pancake coils 3 are arranged at regular intervals along the outer circumferential surface of the coil shaft 2. These pancake coils 3 are arranged so as to be rotationally symmetrical about the axial center of the coil shaft 2.

[0022] In the first embodiment, a six-pole arrangement in which six pancake coils 3 are arranged is illustrated, but the number is not particularly limited. There is no limit to the number as long as two or more pancake coils 3 are arranged on the coil shaft 2 so as to be rotationally symmetric. In addition, while FIG. 1 illustrates a pancake coil 3 corresponding to a six-pole arrangement with two layers, the number of layers and the number of poles of the pancake coil 3 are not limited to the number illustrated in FIG. 1, and other numbers may be used.

[0023] The pancake coil 3 is configured by winding a superconducting wire (not shown) and an insulating member (not shown) in a spiral shape around a coil winding frame (not shown). The superconducting wire is, for example, a high-temperature superconducting wire. A resin layer is filled or impregnated between the superconducting wire and the insulating member.

[0024] Superconducting wire has a multilayer structure in which an intermediate layer, an RE (rare earth element) oxide superconducting layer, and a protective layer are laminated on a tape-shaped metal substrate. Generally, superconducting wire is constructed as a thin-film multilayer wire coated with a stabilizing layer against this multilayer structure.

[0025] The metal substrate is formed from a metal material such as stainless steel or a nickel-based alloy such as Hastelloy (registered trademark).

[0026] The intermediate layer is a layer that plays a role of improving the orientation of the oxide superconducting layer and preventing diffusion, and is made of a material such as magnesium oxide.

[0027] The oxide superconducting layer is a layer that exhibits a superconducting phenomenon. This oxide superconducting layer is, for example, a superconducting thin film having RE123 system (RE1Ba2Cu3Oy). RE is a rare earth element, and indicates elements such as Nd, Gd, Ho, Sm, and Y.

[0028] The protective layer is a layer provided for the purpose of preventing deterioration of the oxide superconducting layer, such as oxidation, etc. This protective layer is made of a material such as Ag.

[0029] The stabilization layer is provided for the purposes of shunting the current when an excessive current flows through the oxide superconducting layer, preventing the oxide superconducting layer from burning, preventing moisture from penetrating into the superconducting wire, and shunting the current from the oxide superconducting layer. This stabilization layer is made of a material such as Cu.

[0030] As shown in FIG. 3, the multiple spacers 4 are members disposed between the pancake coil 3 and the coil shaft 2. For example, six spacers 4 are provided corresponding to the six pancake coils 3, respectively. These spacers 4 are bonded to the corresponding pancake coils 3 and coil shaft 2, respectively. In other words, the front surface of the spacer 4 is bonded to the back surface of the pancake coil 3, and the back surface of the spacer 4 is bonded to the outer circumferential surface of the coil shaft 2. A predetermined adhesive or a resin used for impregnating the superconducting wire is used for bonding them.

[0031] 7 and 8, the spacer 4 has a rectangular shape when viewed from the outer diameter side of the coil shaft 2 (in a plan view). The spacer 4 has a substantially flat plate shape in cross section. The front surface of the spacer 4 is formed into a flat surface that coincides with the back surface of the pancake coil 3. The back surface of the spacer 4 is formed into a curved surface that coincides with the outer circumferential surface of the cylindrical portion 20 of the coil shaft 2.

[0032] The spacer 4 has an opening 40 formed in its center. This opening 40 has a shape that extends in the rotor axial direction (Z direction) so as to match the rectangular shape of the pole piece 22. The opening 40 may be fitted into the pole piece 22 or may be loosely fitted therein. The opening 40 of the spacer 4 is formed at a position that coincides with the bore portion 32 of the pancake coil 3.

[0033] The dimensions of the spacer 4 in the rotor axial direction (Z direction) and the rotor circumferential direction are formed to be approximately the same as the dimensions of the pancake coil 3. In other words, almost the entire area of ​​the back surface of the pancake coil 3 is bonded to the front surface of the spacer 4.

[0034] As shown in Figures 4 and 6, the dimension (thickness) of the spacer 4 in the winding axis direction (W direction) is configured so that the dimensions T2, T4 on the outer periphery of the winding of the pancake coil 3 are larger than the dimensions T1, T3 on the inner periphery of the winding of the pancake coil 3.

[0035] In addition, the pancake coil 3, the coil shaft 2, and the spacer 4 are bonded to each other at their contacting portions so as not to be separated by the centrifugal force C during operation.

[0036] In addition, at least a part of the outer circumferential surface of cylindrical portion 20 of coil shaft 2 is curved so that the distance from the outer circumferential surface of cylindrical portion 20 of coil shaft 2 to the rear surface of pancake coil 3 is larger on the outer circumferential side of the winding of pancake coil 3 than on the inner circumferential side of the winding.

[0037] In the first embodiment, the cylindrical portion 20 has a cylindrical shape, and therefore the outer peripheral surface is curved. The dimension (thickness) of the spacer 4 in the winding axis direction (W direction) is set in accordance with the distance from the outer peripheral surface of the cylindrical portion 20 of the coil shaft 2 to the back surface of the pancake coil 3. The distance may be set by inclining the shape of at least a part of the outer peripheral surface of the cylindrical portion 20. Furthermore, when the outer peripheral surface of the cylindrical portion 20 is inclined, the back surface of the spacer 4 is formed as an inclined surface so as to match the inclination of the outer peripheral surface of the cylindrical portion 20.

[0038] When the rotor 1 is cooled to an operating temperature at which it goes into a superconducting state, the spacer 4, which has been cooled and thermally contracted, applies stresses S1 to S4 to the pancake coil 3 against the centrifugal force C generated by rotation about the coil shaft 2. In other words, the spacer 4 serves as a prestress applying member that utilizes the difference in thermal contraction rate.

[0039] For example, centrifugal force C generated by rotation displaces pancake coil 3 in a direction away from coil shaft 2. Spacer 4 applies stresses S1 to S4 to pancake coil 3 that resist displacement amounts D1 to D4 at this time.

[0040] The spacer 4 is made of a material with a larger linear expansion coefficient than the pancake coil 3 and the coil shaft 2. For example, the spacer 4 is made of an epoxy resin that can be used at extremely low temperatures, or a composite material of resin and fiber 41 (FIG. 7).

[0041] The spacers 4 are arranged inside the pancake coils 3 in the rotor radial direction (R direction) in order to suppress deformation (distortion) of the pancake coils 3 due to centrifugal force C when the rotor 1 rotates. This makes it possible to prevent deterioration of the superconducting characteristics and improve the efficiency of magnetic field generation.

[0042] As shown in Figures 3 and 4, the dimension (thickness) of the spacer 4 in the winding axis direction (W direction) in the straight portion 30 (Figure 7) of the pancake coil 3 is configured so that the dimension T2 on the outer peripheral side of the winding is larger than the dimension T1 on the inner peripheral side of the winding of the pancake coil 3.

[0043] The change in thickness of the spacer 4 from the dimension T1 to the dimension T2 may be configured to increase continuously or stepwise.

[0044] When the spacer 4 is cooled and thermally contracts, each portion of the spacer 4 thermally contracts more at the portion on the outer periphery of the winding (dimension T2) than at the portion on the inner periphery of the winding (dimension T1). Therefore, stress S2 generated on the outer periphery of the winding (dimension T2) is greater than stress S1 generated on the inner periphery of the winding (dimension T1). Here, displacement amount D2 generated by centrifugal force C at the portion on the outer periphery of the winding is greater than displacement amount D1 generated at the portion on the inner periphery of the winding of the pancake coil 3. However, stresses S1 and S2 generated in the spacer 4 act to suppress displacement amounts D1 and D2 generated in the pancake coil 3.

[0045] For example, in the process of cooling to an extremely low temperature to attain a superconducting state, the spacer 4 shrinks relatively more than the other components. Here, the amount of shrinkage of the spacer 4 on the outer periphery side of the winding is greater than that on the inner periphery side of the winding, so the outer periphery side of the winding is displaced more than the inner periphery side of the winding.

[0046] In the operation process following the cooling process, the pancake coil 3 tries to deform outward in the rotor radial direction (R direction) due to centrifugal force C. However, the displacement of the outer periphery of the windings of the pancake coil 3 is offset by the displacement due to thermal contraction of the spacer 4. As a result, the difference between the displacement amounts D1 and D2 between the inner and outer periphery of the windings of the pancake coil 3 during operation becomes smaller. In other words, this acts to reduce distortion inside the pancake coil 3 compared to when the spacer 4 is not present.

[0047] This action makes it possible to avoid deterioration of the characteristics of the high-temperature superconducting coil due to the centrifugal force C during operation of the rotating electric machine, thereby improving the reliability of the rotating electric machine without reducing the efficiency of generating a magnetic field.

[0048] Furthermore, as shown in Figures 5 and 6, the dimension (thickness) of the spacer 4 in the winding axis direction (W direction) of the arc portion 31 (Figure 7) of the pancake coil 3 is configured so that the dimension T4 on the outer peripheral side of the winding is larger than the dimension T3 on the inner peripheral side of the winding of the pancake coil 3.

[0049] Near the end of the cylindrical portion 20, the wall thickness becomes thinner from the center to the end (flange portion 21). As a result, the distance from the outer circumferential surface of the cylindrical portion 20 of the coil shaft 2 to the rear surface of the pancake coil 3 is larger on the outer circumferential side of the windings than on the inner circumferential side of the windings of the pancake coil 3. The dimension (thickness) of the spacer 4 in the winding axis direction (W direction) is set according to this distance, so the dimension T4 on the outer circumferential side of the windings of the pancake coil 3 is larger than the dimension T3 on the inner circumferential side of the windings.

[0050] Furthermore, the dimension (thickness) of the spacer 4 in the winding axis direction (W direction) is configured such that the dimension T4 (FIG. 6) of at least a portion of the arc portion 31 (FIG. 7) is larger than the dimension T1 (FIG. 4) of at least a portion of the straight portion 30 (FIG. 7) of the pancake coil 3.

[0051] The change in thickness of the spacer 4 from the dimension T3 to the dimension T4 may be configured to increase continuously or stepwise.

[0052] When the spacer 4 is cooled and thermally contracted, each portion of the spacer 4 thermally contracts more at the portion on the outer periphery of the winding (dimension T4) than at the portion on the inner periphery of the winding (dimension T3). Therefore, stress S4 generated on the outer periphery of the winding (dimension T4) is greater than stress S3 generated on the inner periphery of the winding (dimension T3). Here, displacement amount D4 of the portion on the outer periphery of the winding is greater than displacement amount D3 of the portion on the inner periphery of the winding of the pancake coil 3 generated by centrifugal force C. However, stresses S3 and S4 generated in the spacer 4 act to suppress displacement amounts D3 and D4 generated in the pancake coil 3.

[0053] For example, in the process of cooling to an extremely low temperature to obtain a superconducting state, the spacer 4 shrinks relatively more than the other components. Here, in each portion of the spacer 4, the amount of shrinkage in the winding axis direction (W direction) is greater near the outermost circumference than near the innermost circumference of the arc portion 31 of the pancake coil 3, so that the vicinity of the outermost circumference acts to displace more than the vicinity of the innermost circumference.

[0054] In the operation process following the cooling process, the arc portion 31 of the pancake coil 3 tends to deform more near the outermost circumference than near the innermost circumference due to centrifugal force C. However, the displacement near the outermost circumference of the arc portion 31 is offset by the displacement due to thermal contraction of the spacer 4. Therefore, the difference in the displacement amounts D3, D4 between the innermost circumference and the outermost circumference of the arc portion 31 during operation becomes smaller. In other words, this acts to reduce distortion inside the pancake coil 3 compared to when the spacer 4 is not present.

[0055] This action makes it possible to avoid deterioration of the characteristics of the high-temperature superconducting coil due to the centrifugal force C during operation of the rotating electric machine, thereby improving the reliability of the rotating electric machine without reducing the efficiency of generating a magnetic field.

[0056] Next, the spacer 4 will be described in detail with reference to Fig. 7 and Fig. 8. In the plan view of the spacer 4 in Fig. 7, the vertical direction on the paper surface is the rotor axial direction (Z direction), and the left and right direction on the paper surface is the rotor circumferential direction. In addition, in the cross-sectional view (side view) of the spacer 4 in Fig. 8, the vertical direction on the paper surface is the winding axis direction (W direction), and the left and right direction on the paper surface is the rotor circumferential direction.

[0057] The spacer 4 is made of a material having an anisotropic linear expansion coefficient, and is configured so that the linear expansion coefficient in the winding axis direction (W direction) is higher than the linear expansion coefficients in the rotor circumferential direction and the rotor axial direction (Z direction). Here, the rotor circumferential direction is the in-plane direction perpendicular to the rotor axial direction (Z direction) in Fig. 7 and perpendicular to the winding axis direction (W direction) in Fig. 8.

[0058] It is preferable that the linear expansion coefficient of the spacer 4 in the rotor circumferential direction and the rotor axial direction (Z direction) is not significantly different from that of the pancake coil 3.

[0059] In the process of cooling to extremely low temperatures, the difference in linear expansion coefficient between the pancake coil 3 and the spacer 4 reduces the shear stress due to the difference in strain, i.e., the thermal stress applied to the pancake coil 3. Furthermore, the displacement in the rotor radial direction (R direction) during cooling is larger near the outermost circumference than near the innermost circumference of the pancake coil 3, which is fixed to the pole piece 22 of the coil shaft 2. In the subsequent operating process, the displacement in the rotor radial direction (R direction) is offset, and the strain inside the pancake coil 3 is reduced.

[0060] Fiber reinforced plastic (FRP), which is a material having anisotropic linear expansion coefficient, is used as the material of the spacer 4. Here, by changing the lamination direction of the multiple fibers 41 of the fiber reinforced plastic, it is possible to make the linear expansion coefficient different between the rotor circumferential direction and rotor axial direction (Z direction) and the winding axial direction (W direction).

[0061] 7, a plurality of fibers 41 are arranged in a lattice (matrix) pattern in plan view of the spacer 4. That is, a plurality of fibers 41 extending in the rotor circumferential direction are arranged side by side (stacked) in the rotor axial direction (Z direction), and a plurality of fibers 41 extending in the rotor axial direction (Z direction) are arranged side by side (stacked) in the rotor circumferential direction.

[0062] 8, the fibers 41 are arranged in a ruled line pattern (a blind pattern) in the cross-sectional view (side view) of the spacer 4. In other words, the fibers 41 extending in the rotor circumferential direction are arranged side by side (stacked) in the winding axis direction (W direction).

[0063] By configuring the spacer 4 so that the linear expansion coefficient in the winding axis direction (W direction) is higher than the linear expansion coefficient in the rotor circumferential direction and rotor axial direction (Z direction) due to the difference in the stacking direction of the multiple fibers 41, the above-mentioned effect can be obtained.

[0064] This action makes it possible to avoid deterioration of the characteristics of the pancake coil 3 due to the centrifugal force C during operation of the rotating electric machine. This makes it possible to increase the reliability of the superconducting rotating electric machine without reducing the efficiency of generating a magnetic field.

[0065] Second embodiment Next, a second embodiment will be described with reference to Fig. 9. Note that the same components as those shown in the above-described embodiment are denoted by the same reference numerals and the duplicated description will be omitted.

[0066] The rotor 1A of the second embodiment includes a fixing member 5 that comes into contact with the surface of the pancake coil 3 in the arc portion 31 (FIG. 7), is fixed to the coil shaft 2, and fixes the pancake coil 3. For example, one rotor 1 includes a plurality of fixing members 5, and each fixing member 5 is disposed in a corresponding arc portion 31.

[0067] The fixed member 5 is a member having a rectangular plate shape. The fixed member 5 is fixed to the flange portion 21 of the coil shaft 2 by a fastening member (not shown) such as a screw. In other words, the fixed member 5 is mechanically fixed to the coil shaft 2 so as not to be deformed outward in the rotor radial direction (R direction) due to the centrifugal force C (FIG. 6) generated when the rotor 1A rotates.

[0068] In addition, the back surface of fixing member 5 is in contact with the surface of arc portion 31 of pancake coil 3. In other words, fixing member 5 is configured to be in contact with the surface of arc portion 31 of pancake coil 3 that is on the outer side in the rotor radial direction (R direction).

[0069] Since the fixing member 5 is disposed further outboard than the pancake coil 3 in the rotor radial direction (R direction), it acts to reduce the displacement of the arc portion 31 of the pancake coil 3 caused by the centrifugal force C during rotation.

[0070] Due to this action, it is possible to avoid deterioration of the characteristics of the pancake coil 3 due to the centrifugal force C during operation of the rotating electric machine, thereby improving the reliability of the rotating electric machine.

[0071] The rotor 1 of the first embodiment described above is configured such that the dimension (thickness) of the spacer 4 in the winding axis direction (W direction) at the arc portion 31 is greater at the dimension T4 on the outer periphery of the winding than at the dimension T3 on the inner periphery of the winding of the pancake coil 3 (FIG. 6). That is, the rotor 1 of the first embodiment is shaped so that the thickness of the spacer 4 at the arc portion 31 varies. However, by providing the fixing member 5, the rotor 1A of the second embodiment can omit the shape of the spacer 4 at the arc portion 31 that varies in thickness as in the first embodiment.

[0072] Third embodiment Next, a third embodiment will be described with reference to Fig. 10. Note that the same components as those shown in the above-mentioned embodiments are denoted by the same reference numerals and the duplicated description will be omitted.

[0073] A rotor 1B of the third embodiment is provided with a plurality of spacers 4B and a plurality of fixing members 5B.

[0074] Here, the spacer 4B of the third embodiment is provided only in the area corresponding to the straight portion 30 (FIG. 7) of the pancake coil 3, and is not provided in the area corresponding to the arc portion 31 (FIG. 7) of the pancake coil 3. In other words, the dimension of the spacer 4B of the third embodiment in the rotor axial direction (Z direction) is shorter than that of the spacer 4B of the first embodiment.

[0075] The fixing member 5B is a member that has a U-shape in cross section. The fixing member 5B is fixed to the outer circumferential surface of the cylindrical portion 20 of the coil shaft 2 by a fastening member (not shown) such as a screw. The fixing member 5B is configured to contact the front and back surfaces of the arc portion 31 of the pancake coil 3 so as to sandwich the arc portion 31.

[0076] Since the arcuate portion 31 of the pancake coil 3 is fixed by the fixing member 5B, the displacement of the arcuate portion 31 of the pancake coil 3 due to the centrifugal force C (FIG. 6) during rotation is reduced.

[0077] Due to this action, it is possible to avoid deterioration of the characteristics of the pancake coil 3 due to the centrifugal force C during operation of the rotating electric machine, thereby improving the reliability of the rotating electric machine.

[0078] Furthermore, by using the fixing member 5B of the third embodiment, the spacer 4B can be formed to have a short size, and therefore the manufacturing cost of the spacer 4B can be reduced.

[0079] The present invention has been described above based on the first to third embodiments, but the configuration applied in any of the embodiments may be applied to the other embodiments, and the configurations applied in each embodiment may be combined.

[0080] In the above embodiment, six pancake coils 3 and spacers 4 are provided for one rotor 1, but other configurations are also possible. For example, five or less or seven or more pancake coils 3 and spacers 4 may be provided for one rotor 1.

[0081] In the above embodiment, the pancake coil 3 has an elliptical shape in a plan view, but may have other shapes. For example, the pancake coil 3 may have a circular shape, an elliptical shape, or an egg shape.

[0082] According to at least one of the embodiments described above, the rotor 1 includes the spacer 4 disposed between the pancake coil 3 and the coil shaft 2 and bonded to each of them. This makes it possible to prevent deterioration of the superconducting characteristics and improve the efficiency of magnetic field generation, thereby enhancing the reliability of the superconducting rotating electric machine.

[0083] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations can be made without departing from the spirit of the invention. These embodiments or modifications thereof are within the scope of the invention and its equivalents as described in the claims, as well as within the scope and spirit of the invention. [Explanation of symbols]

[0084] 1,1A,1B...rotor, 2...coil shaft, 3...pancake coil, 4,4B...spacer, 5,5B...fixing member, 20...cylindrical portion, 21...flange portion, 22...pole piece, 30...straight portion, 31...arc portion, 32...bore portion, 40...opening, 41...fiber, C...centrifugal force, D1,D2,D3,D4...displacement, S1,S2,S3,S4...stress, T1,T2,T3,T4...dimension, W...winding axis, Z...rotation axis.

Claims

1. A coil shaft that serves as the axis of a rotor of a rotating electric machine; a pancake coil for a field winding, which is held on an outer circumferential surface of the coil shaft and is wound with a tape-shaped superconducting wire; a spacer disposed between the pancake coil and the coil shaft and bonded to each other; Equipped with The spacer is configured such that a dimension in a winding axis direction of the pancake coil is larger on an outer peripheral side of the winding of the pancake coil than on an inner peripheral side of the winding of the pancake coil. Rotor for superconducting rotating electric machine.

2. The spacer, which is cooled and thermally shrunk, applies stress to the pancake coil against the centrifugal force generated by rotation about the coil shaft.

2. The rotor for a superconducting rotating electric machine according to claim 1.

3. At least a part of the outer circumferential surface of the coil shaft is curved or inclined so that a distance from the outer circumferential surface of the coil shaft to a rear surface of the pancake coil is larger on the outer circumferential side of the winding of the pancake coil than on the inner circumferential side of the winding of the pancake coil.

3. A rotor for a superconducting rotating electric machine according to claim 1 or 2.

4. the spacer is formed of a material having an anisotropic linear expansion coefficient, and configured so that the linear expansion coefficient in the winding axis direction is higher than the linear expansion coefficient in the rotor circumferential direction and the rotor axial direction.

3. A rotor for a superconducting rotating electric machine according to claim 1 or 2.

5. The pancake coil has an elliptical shape including a straight portion and an arc portion, a dimension of the spacer in the winding axis direction in the straight portion of the pancake coil is larger on the outer peripheral side of the winding of the pancake coil than on the inner peripheral side of the winding of the pancake coil; 3. A rotor for a superconducting rotating electric machine according to claim 1 or 2.

6. The pancake coil has an elliptical shape including a straight portion and an arc portion, a dimension of the spacer in the winding axis direction in the arc portion of the pancake coil is larger on the outer circumferential side of the winding of the pancake coil than on the inner circumferential side of the winding of the pancake coil; 3. A rotor for a superconducting rotating electric machine according to claim 1 or 2.

7. The pancake coil has an elliptical shape including a straight portion and an arc portion, The spacer is configured such that a dimension in the winding axis direction of at least a portion of the arcuate portion is larger than a dimension in the straight portion of the pancake coil.

3. A rotor for a superconducting rotating electric machine according to claim 1 or 2.

8. The pancake coil has an elliptical shape including a straight portion and an arc portion, a fixing member that contacts a surface of the pancake coil at the arc portion, is fixed to the coil shaft, and fixes the pancake coil; 3. A rotor for a superconducting rotating electric machine according to claim 1 or 2.

9. A rotor for a superconducting rotating electric machine according to claim 1 or 2, Superconducting rotating motor.

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