Jig

Abstract

To more easily heat an armature by induction heating.SOLUTION: A jig used when inductively heating a heated body by passing current through an induction coil, the jig is positioned between the induction coil and the heated body when viewed from the direction of current flow through the induction coil, the jig has a non-magnetized region and a magnetized region that can be magnetized by a magnetic field generated by passing current through the induction coil, the non-magnetized region is positioned on a straight line passing through the induction coil and the heated body when viewed from the direction of current flow, and the magnetized regions is provided on one side and the other side of the non-magnetized region in a direction along the magnetic field.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a jig. [Background technology]

[0002] Patent Documents 1 and 2 disclose that the armature is heated by induction heating in order to fix a paint (for example, varnish) applied to the armature. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-74749 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-118731 Summary of the Invention [Problem to be solved by the invention]

[0004] Heating of an armature by induction heating is achieved by placing the armature in the magnetic field generated by an induction coil. To place the armature in the magnetic field, several types of induction coils may be used depending on the size of the armature (e.g., outer diameter, inner diameter). However, stocking a plurality of induction coils and changing the setup each time is time-consuming and costly. Therefore, there is a demand for a method for more easily heating an armature by induction heating. [Means for solving the problem]

[0005] One aspect of the present invention is A jig used when inductively heating a heated object by energizing an induction coil, the jig is disposed between the induction coil and the object to be heated as viewed from the direction of current flow through the induction coil, the jig has a non-magnetized region and a magnetized region that can be magnetized by a magnetic field generated by energizing the induction coil, When viewed from the direction of current flow, the non-magnetized area is arranged on a straight line passing through the induction coil and the heated object, and the magnetized areas are provided on one side and the other side of the non-magnetized area in the direction along the magnetic field. [Effects of the Invention]

[0006] According to one aspect of the present invention, heating of the armature by induction heating can be more easily performed. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating the jig. [Figure 2] FIG. 2 is a diagram illustrating the jig. [Figure 3] FIG. 3 is a diagram illustrating the jig. [Figure 4] FIG. 4 is a diagram illustrating the jig. [Figure 5] FIG. 5 is a diagram illustrating a comparative example. [Figure 6] FIG. 6 is a diagram illustrating a jig according to the first modification. [Figure 7] FIG. 7 is a diagram illustrating a jig according to the second modification. [Figure 8] FIG. 8 is a diagram illustrating a jig according to the second modification. [Figure 9] FIG. 9 is a diagram illustrating a jig according to the third modification. [Figure 10] FIG. 10 is a diagram illustrating a jig according to the third modification. [Figure 11] FIG. 11 is a diagram illustrating a jig according to the fourth modification. DETAILED DESCRIPTION OF THE INVENTION

[0008] First, definitions of terms used in this specification will be explained. "Overlapping when viewed in a predetermined direction" means that multiple elements are lined up in a predetermined direction, and is synonymous with "overlapping in a predetermined direction." The "predetermined direction" may be, for example, an axial direction, a radial direction, or the direction of gravity. When a drawing shows multiple elements (components, parts, etc.) arranged in a specific direction, it may be assumed that the description in the specification contains a sentence explaining that they overlap when viewed in the specific direction.

[0009] "Not overlapping when viewed in a predetermined direction" and "offset when viewed in a predetermined direction" mean that multiple elements are not lined up in a predetermined direction, and are synonymous with "not overlapping in a predetermined direction" and "offset in a predetermined direction." The "predetermined direction" is, for example, the axial direction, the radial direction, the direction of gravity, etc. If a drawing shows that multiple elements (components, parts, etc.) are not aligned in a specified direction, it may be assumed that the description in the specification contains a sentence explaining that they do not overlap when viewed in the specified direction.

[0010] "When viewed from a predetermined direction, a first element (component, part, etc.) is located between a second element (component, part, etc.) and a third element (component, part, etc.)" means that when observed from a predetermined direction, it can be observed that the first element is located between the second element and the third element. The "predetermined direction" refers to an axial direction, a radial direction, the direction of gravity, etc. For example, if the second element, the first element, and the third element are arranged in that order along the axial direction, it can be said that the first element is located between the second element and the third element when viewed in the radial direction. If the drawings show that the first element is located between the second element and the third element when viewed in a specific direction, it can be considered that the description in the specification contains a sentence explaining that the first element is located between the second element and the third element when viewed in the specific direction.

[0011] The present embodiment will be described below. In this embodiment, a stator 5 of a motor will be described as an example of an armature that is a heated body. Fig. 1 is a diagram illustrating the jig 1. Fig. 1 shows the jig 1 disposed between a stator 5 and a heating device 6. In Fig. 1, the magnetic material portion 10 and the non-magnetic material portion 11 of the jig 1 are cross-hatched at different pitches. 2 is a diagram illustrating the jig 1. FIG. 2 is a schematic diagram of a cross section obtained by cutting the jig 1, the stator 5, and the heating device 6 of FIG. 3 is a diagram illustrating the jig 1. FIG. 3 is a schematic diagram of the AA cross section of FIG. 4 is a diagram illustrating the jig 1. FIG. 4 is an enlarged view of region A in FIG. Fig. 5 is a diagram for explaining a comparative example, showing the direction of the magnetic field H when the jig 1 is not provided. 3 to 5, the shape of the stator core 50 is simplified.

[0012] 1, the stator 5 is ring-shaped when viewed from the direction of the rotation axis X. The stator 5 is set in a holder 9 together with a heating device 6 and a jig 1 (to be described later) with the rotation axis X oriented along the vertical line.

[0013] 2, the holder 9 has a cylindrical portion 91 oriented along the direction of the rotation axis X (the vertical direction in the figure), and a flange portion 92 protruding radially outward from a lower end 91b of the cylindrical portion 91. The holder 9 is fixed to, for example, a workbench T or the like at the side of the lower end 91b of the cylindrical portion 91.

[0014] The stator 5 has a cylindrical stator core 50 that surrounds the rotation axis X. Stator core 50 is formed by laminating multiple electromagnetic steel plates, and has yoke portion 51 that is ring-shaped when viewed in the direction of rotation axis X, and teeth portion 52 that protrude from the inner periphery of yoke portion 51 toward rotation axis X. Coils 53 are wound around teeth portion 52.

[0015] 2, coil ends 53a, 53b of coil 53 each protrude in the direction of rotation axis X (up and down in the figure) from stator core 50. When stator 5 is set in holder 9, lower end 50a of stator core 50 abuts on upper end 91a of cylindrical portion 91, and coil end 53b is housed on the inner diameter side of cylindrical portion 91.

[0016] Varnish V is applied to the entire surface of the coil 53. The varnish V hardens when heated. In this embodiment, the stator core 50 is induction heated using a heating device 6 equipped with an induction coil 7. The heat from the heated stator core 50 is transferred to the coil 53. This heats the coil 53, ultimately heating and hardening the varnish V.

[0017] 1, the heating device 6 has an induction coil 7 and a support part 8 that supports the induction coil 7. The support part 8 has a cylindrical shape that surrounds the stator 5. The support part 8 is made of a non-magnetic material that is not magnetized even when the magnetic field of the induction coil 7 acts on it. In this embodiment, the induction coil 7 is provided inside the support portion 8, but the manner of support is not particularly limited. For example, the induction coil 7 may be fixed to the inner circumferential surface of the support portion 8 or to the outer circumferential surface.

[0018] 2, the heating device 6 is set in the holder 9 with the support portion 8 oriented along the rotation axis X. When the heating device 6 is set in the holder 9, the lower end 8a of the support portion 8 abuts against the upper end 92a of the flange portion 92.

[0019] 1, induction coil 7 is provided in a range surrounding the entire circumference of jig 1 in the circumferential direction about rotation axis X. One end 7a and the other end 7b of induction coil 7 in the circumferential direction about rotation axis X are connected to power supply 60 via wires 61 and 62, respectively. For example, wire 61 is connected to a positive terminal (not shown) of power supply 60, and wire 62 is connected to a negative terminal (not shown) of power supply 60. Therefore, current I flows from one end 7a of induction coil 7 to the other end 7b.

[0020] The induction coil 7 has a straight portion 71 provided in the direction along the rotation axis X, and arc-shaped portions 72 and 73 provided in the direction along the circumferential direction of the rotation axis X. A plurality of straight portions 71 are provided at intervals in the circumferential direction around the rotation axis X. The arc-shaped portions 72 connect one ends of the straight portions 71 in the direction of the rotation axis X. The arc-shaped portions 73 connect the other ends of the straight portions 71 in the direction of the rotation axis X. The arc-shaped portions 72, 73 are provided alternately in the circumferential direction around the rotation axis X.

[0021] As shown in FIG. 2, the straight portion 71 of the induction coil 7 has a length L71 in the direction of the rotation axis X that is longer than the length L50 of the stator core 50 (L71>L50). Therefore, when the heating device 6 is set in the holder 9, the stator core 50 overlaps with the straight portions 71 of the induction coil 7 over the entire length in the direction of the rotation axis X when viewed from the radial direction. In addition, the arc-shaped portions 72 (see the dashed lines in the drawing) connect one ends of the straight portions 71 together at positions offset from the stator core 50. Note that, although not shown, the arc-shaped portions 73 also connect the other ends of the straight portions 71 together at positions offset from the stator core 50.

[0022] 1, when a current I is applied from a power source 60 to the induction coil 7, the direction of current flow in the straight portions 71 is along the rotation axis X. In this case, the directions of current I flow in the straight portions 71 adjacent to each other in the circumferential direction around the rotation axis X are opposite to each other (directions of arrows a and b in the figure).

[0023] 1, when a current I flows in the direction of arrow a, the direction of the magnetic field H formed around the straight portion 71 is counterclockwise (CCW). When a current I flows in the direction of arrow b, the direction of the magnetic field H formed around the straight portion 71 is clockwise (CW) (right-hand rule).

[0024] As shown in Fig. 3, eight straight portions 71 of the induction coil 7 are provided at intervals in the circumferential direction around the rotation axis X. The eight straight portions 71 are provided on an imaginary circle Im1 whose center is the rotation axis X. In Fig. 3, the straight portion 71 through which the current I flows from the back side of the page to the front side (corresponding to arrow a in Fig. 1) is indicated by a symbol consisting of a black circle within a white circle. Furthermore, the straight portion 71 through which the current I flows from the front side of the page to the back side (corresponding to arrow b in Fig. 1) is indicated by a symbol consisting of a cross within a white circle. In this embodiment, the induction coil 7 has eight straight portions 71, but the number of straight portions 71 can be set to any number. The number of straight portions 71 may be seven or less, or nine or more.

[0025] Here, as shown in FIG. 5, the magnetic field H is formed in a circular shape with the straight portion 71 at the center. Therefore, the distance K between the stator core 50 of the stator 5 and the straight portion 71 of the induction coil 7 in the radial direction may become longer than the range of the magnetic field H. In this case, if the space R between the stator core 50 and the straight portion 71 is composed of, for example, a layer of non-magnetized air, the magnetic field H may not reach the stator core 50. In this case, the stator core 50 is not heated, and the varnish V (see FIG. 2) is not hardened. For example, it is conceivable to prepare a separate induction coil 7 shaped so that the magnetic field H reaches the stator core 50, but stocking multiple different types of induction coils 7 and the support parts 8 that support the induction coils 7 and replacing them each time would increase the effort and cost.

[0026] Therefore, in this embodiment, the jig 1 is placed in the space R between the stator core 50 and the induction coil 7 in the radial direction of the rotation axis X, to control the range of the magnetic field H.

[0027] As shown in FIG. 1, the jig 1 has a cylindrical shape that surrounds the stator core 50. The jig 1 is set in the holder 9 in a state where it is oriented along the rotation axis X. As shown in FIG. 2, the length L1 of the jig 1 in the direction of the rotation axis X is set to a length that is approximately consistent with the length L50 of the stator core 50 (L1≈L50).

[0028] As shown in Figure 1, the jig 1 is composed of a magnetic part 10 (magnetized region) made of a material (magnetic material) that is magnetized by the action of a magnetic field, and a non-magnetic part 11 (non-magnetized region) made of a material (non-magnetic material) that is not magnetized even when a magnetic field is applied. The magnetic material portion 10 can be made of a material that is magnetized by the action of a magnetic field, such as a soft magnetic material such as electromagnetic steel, while the non-magnetic material portion 11 can be made of a material that is not magnetized by the action of a magnetic field, such as copper, aluminum, or a resin material.

[0029] As shown in FIG. 3, the magnetic material portion 10 and the non-magnetic material portion 11 are each formed in an arc shape having the same outer diameter and inner diameter. The width W10 of the magnetic material portion 10 in the circumferential direction around the rotation axis X is set to be larger than the width W11 of the non-magnetic material portion 11 (W10>W11).

[0030] The jig 1 is formed in a ring shape along an imaginary circle Im2 centered on the rotation axis X by arranging eight magnetic material portions 10 and eight non-magnetic material portions 11 alternately in the circumferential direction around the rotation axis X. The magnetic material portions 10 and the non-magnetic material portions 11 are fixed to each other so that they cannot move. The magnetic material portions 10 and the non-magnetic material portions 11 may be fixed using an adhesive, or they may be engaged with each other by providing an engaging protrusion and an engaging groove on their mating surfaces.

[0031] A method for heating the stator core 50 using the jig 1 will be described below. First, as shown in Fig. 1, the jig 1 is set in the holder 9. Specifically, the jig 1 is placed in the space R between the stator core 50 and the induction coil 7 in the radial direction of the rotation axis X, and the lower end 1a (see Fig. 2) of the jig 1 is brought into contact with the upper end 91a of the cylindrical portion 91 of the holder 9 (placement step).

[0032] As a result, the space R between the stator core 50 and the induction coil 7 is filled with the jig 1. When viewed from the radial direction, the stator core 50 overlaps with the jig 1 and the induction coil 7 over the entire length in the direction of the rotation axis X (see FIG. 2).

[0033] 3, the jig 1 is displaced in the circumferential direction around the rotation axis X to position the non-magnetic material portion 11 on the straight line Lm (Lm1 to Lm8) (positioning step). The straight line Lm is a line connecting the rotation axis X and the straight line portion 71 when viewed from the direction of the rotation axis X. In other words, the straight line Lm is a line passing through the straight line portion 71 and the stator core 50 when viewed from the current-carrying direction (the front-to-back direction on the paper in FIG. 3). As a result, the non-magnetic portion 11 and the straight portion 71 of the induction coil 7 face each other in the radial direction of the rotation axis X.

[0034] Finally, the power supply 60 (see FIG. 1) of the heating device 6 is turned on to pass a current I through the induction coil 7, thereby generating a magnetic field H (heating step). As shown in FIG. 1, when a current I is passed through the induction coil 7, magnetic fields H aligned in a counterclockwise direction CCW and magnetic fields H aligned in a clockwise direction CW are alternately formed in the straight line portions 71 aligned in the circumferential direction around the rotation axis X.

[0035] As shown in FIG. 4, when viewed from the straight portion 71, the magnetic material portion 10 is located on one side and the other side of the non-magnetic material portion 11 in the direction along the magnetic field H (clockwise direction CW or counterclockwise direction CCW).

[0036] When the magnetic field H formed around the straight portion 71 acts on the jig 1, the magnetic field lines forming the magnetic field H can pass through the magnetic material portion 10 but cannot pass through the non-magnetic material portion 11. As a result, the magnetic material portion 10 is magnetized in a direction along the magnetic field H, but the non-magnetic material portion 11 is not magnetized. Therefore, the magnetic field H is formed so as to pass through the magnetic material portion 10 on one side (upstream side in the direction of the arrow), then cross the non-magnetic material portion 11 and head toward the magnetic material portion 10 on the other side (downstream side in the direction of the arrow).

[0037] As a result, the portion of the magnetic field H that straddles the non-magnetic material portion 11 is extended significantly toward the rotation axis X, and acts on the yoke portion 51 side (outer periphery side) of the stator core 50. This generates an eddy current in the stator core 50, heating the stator core 50. The heat of the heated stator core 50 is ultimately transferred from the coil 53 to the varnish V (see FIG. 2), hardening the varnish V.

[0038] In this embodiment, eight straight portions 71 of the induction coil 7 and eight non-magnetic portions 11 of the jig 1 are provided at intervals in the circumferential direction around the rotation axis X. Therefore, the magnetic field H acts on the stator core 50 from eight locations surrounding the rotation axis X (see FIGS. 3 and 4). This makes it less likely that uneven heating will occur when the stator core 50 is heated.

[0039] In this way, by simply providing the jig 1 between the stator core 50 and the induction coil 7, the magnetic field H generated from the induction coil 7 can be made to reach the stator core 50 side. Therefore, even when heating a plurality of types of stator cores 50 with different sizes, one induction coil 7 can be shared. Therefore, the stator cores 50 can be heated more easily than if a plurality of induction coils 7 according to sizes and supports 8 for supporting the induction coils 7 were stocked and replaced each time.

[0040] Examples of the jig 1 according to an embodiment of the present invention are listed below. (1) The jig 1 is used when applying current to the induction coil 7 to inductively heat the stator core 50 (object to be heated). The jig 1 is disposed between the induction coil 7 and the stator core 50 when viewed from the direction of the rotation axis X along the current-carrying direction of the induction coil 7. The jig 1 has a non-magnetic part 11 (non-magnetized region) and a magnetic part 10 (magnetized region) that can be magnetized by a magnetic field H generated by energizing the induction coil 7. When viewed from the direction of the rotation axis X, the non-magnetic material part 11 is arranged on a straight line Lm passing through the induction coil 7 and the stator core 50, and the magnetic material part 10 is provided on one side and the other side of the non-magnetic material part 11 in the direction along the magnetic field H.

[0041] With this configuration, when a magnetic field H acts on the jig 1 from the induction coil 7, the magnetic field lines forming the magnetic field H can pass through the magnetic material portion 10 but cannot pass through the non-magnetic material portion 11. As a result, the magnetic material portion 10 is magnetized in a direction along the magnetic field H, but the non-magnetic material portion 11 is not magnetized. Therefore, the magnetic field H is formed so as to pass through the magnetic material portion 10 on one side, then cross the non-magnetic material portion 11 and head toward the magnetic material portion 10 on the other side. Therefore, the magnetic field H acting on the jig 1 from the induction coil 7 is formed across the non-magnetic material portion 11, from the magnetic material portion 10 on one side of the non-magnetic material portion 11 to the magnetic material portion 10 on the other side (see Figure 4). As a result, the portion of the magnetic field H that straddles the non-magnetic material portion 11 is extended significantly toward the rotation axis X side, and acts on the stator core 50. As a result, an eddy current is generated in the stator core 50, and the stator core 50 is heated. Therefore, by using the jig 1, one induction coil 7 can be shared among a plurality of types of stators 5 having different sizes of stator cores 50. This makes it easier to heat the stator core 50 than stocking a plurality of induction coils 7 according to the sizes of the stators 5 and replacing them each time.

[0042] (2) The stator 5 having the stator core 50 is an armature. The stator core 50 has a ring shape when viewed from the direction of the rotation axis X. The linear portions 71 of the induction coil 7 are provided on the yoke portion 51 side (outer periphery side) of the stator core 50, oriented along the direction of the rotation axis X, and are provided at intervals in the circumferential direction around the rotation axis X. The jig 1 has a cylindrical shape surrounding the rotation axis X. When viewed from the direction of the rotation axis X, the magnetic material portions 10 and the non-magnetic material portions 11 are alternately provided in the circumferential direction around the rotation axis X. When viewed from the direction of the rotation axis X, the non-magnetic material portion 11 is provided on a straight line Lm that connects the linear portion 71 of the induction coil 7 and the rotation axis X.

[0043] With this configuration, when the magnetic field H formed around the straight portion 71 acts on the jig 1, the magnetic field lines forming the magnetic field H can pass through the magnetic material portion 10 but cannot pass through the non-magnetic material portion 11. As a result, the magnetic material portion 10 is magnetized in a direction along the magnetic field H, but the non-magnetic material portion 11 is not magnetized. Therefore, the magnetic field H is formed so as to pass through the magnetic material portion 10 on one side, then cross the non-magnetic material portion 11 and head toward the magnetic material portion 10 on the other side. As a result, the portion of the magnetic field H that straddles the non-magnetic material portion 11 is extended significantly toward the rotation axis X side, and acts on the stator core 50. As a result, an eddy current is generated in the stator core 50, and the stator core 50 is heated. In this case, the stator core 50 is heated by the magnetic field H acting on it from a plurality of locations in the circumferential direction around the rotation axis X. This makes it less likely that uneven heating will occur when the stator core 50 is heated.

[0044] (4) The magnetic part 10 is made of a material (magnetic material) that is magnetized by the action of a magnetic field. The non-magnetic portion 11 is made of a material (non-magnetic material) that is not magnetized even when a magnetic field acts on it.

[0045] With this configuration, when the magnetic field H acts on the jig 1, the magnetic material portions 10 are magnetized in a direction along the magnetic field H, but the non-magnetic material portions 11 are not magnetized. As a result, in the magnetic field H, the portion spanning the non-magnetic material portions 11 is significantly extended toward the rotation axis X side, and can reach the stator core 50.

[0046] The present invention can also be specified as a method for heating a stator 5 using the jig 1. in particular, (6) A method for heating the stator core 50 using the jig 1. a placement step of placing the jig 1 between the induction coil 7 and the stator core 50; a positioning step of arranging the non-magnetic portion 11 opposite the induction coil 7; and a heating step of generating a magnetic field H by energizing the induction coil 7 and causing the magnetic field H to extend beyond the non-magnetic material portion 11 to the stator core 50, thereby heating the stator core 50.

[0047] As a result, the portion of the magnetic field H that straddles the non-magnetic material portion 11 is extended significantly toward the rotation axis X side, and acts on the stator core 50. Therefore, an eddy current is generated in the stator core 50, and the stator core 50 can be heated.

[0048] (Variation 1) In the above embodiment, the non-magnetic portion 11 is made of a material that is not magnetized even when the magnetic field H acts on it, but the present invention is not limited to this. Instead of the material that is not magnetized even when the magnetic field H acts on it, for example, an air layer may be used.

[0049] Fig. 6 is a diagram illustrating a jig 1A according to Modification 1. In Fig. 6, the shape of a stator core 50 is simplified. In the following description, the same components as those in the embodiment will be denoted by the same reference numerals, and detailed description thereof will be omitted.

[0050] 6, the jig 1A according to the first modification has a cylindrical magnetic body 12 (magnetized region) surrounding the rotation axis X, and a through-hole 13 (non-magnetized region) penetrating the magnetic body 12 in the direction of the rotation axis X. The magnetic body 12 is made of a material that is magnetized by the action of a magnetic field. The inside of the through-hole 13 is an air space, and therefore is a region that is not magnetized even when a magnetic field acts on it.

[0051] A plurality of through holes 13 are provided at intervals in the circumferential direction around the rotation axis X along an imaginary circle Im2 centered on the rotation axis X. In the jig 1A, when viewed from the direction of the rotation axis X, the multiple through holes 13 are each arranged on a straight line Lm connecting the linear portion 71 of the induction coil 7 and the rotation axis X. As a result, the through holes 13 are arranged side by side with the linear portion 71 of the induction coil 7 in the radial direction of the rotation axis X.

[0052] When the magnetic field H formed around the straight portion 71 acts on the jig 1A, the magnetic field lines forming the magnetic field H can pass through the magnetic material portion 12 but cannot pass through the through hole 13. Therefore, the magnetic material portion 12 is magnetized in a direction along the magnetic field H, but the through hole 13 is not magnetized. Therefore, the magnetic field H is formed so as to pass through the magnetic material portion 12 on one side (upstream side in the direction of the arrow), straddle the through hole 13, and head toward the magnetic material portion 12 on the other side (downstream side in the direction of the arrow).

[0053] As a result, the portion of the magnetic field H that straddles the through-hole 13 is extended significantly toward the rotation axis X side, and acts on the yoke portion 51 side (outer periphery side) of the stator core 50. Therefore, an eddy current is generated in the stator core 50, and the stator core 50 is heated.

[0054] The jig 1A according to the first modification has the following configuration. (5) The magnetic part 12 is made of a material (magnetic material) that is magnetized by the action of a magnetic field. The inside of the through-hole 13 is made up of a layer of air that is not magnetized even when a magnetic field acts on it.

[0055] With this configuration, when the magnetic field H acts on the jig 1A, the magnetic material portion 12 is magnetized in a direction along the magnetic field H, but the area where the through hole 13 is provided is not magnetized. This allows the magnetic field H to be extended significantly toward the rotation axis X side at the portion spanning the through hole 13, and to reach the stator core 50.

[0056] (Variation 2) In the above embodiment, the non-magnetic portion 11 of the jig 1 and the linear portion 71 of the induction coil 7 are formed linearly along the rotation axis X, but the present invention is not limited to this. For example, the non-magnetic portion and the induction coil may have a spiral shape.

[0057] Fig. 7 is a diagram illustrating a jig 1B according to Modification 2. In Fig. 7, the holder 9 is omitted. 8 is a diagram illustrating a jig 1B according to Modification 2. FIG. 8 is a schematic diagram of a cross section obtained by cutting the jig 1B, the stator 5, and the heating device 6A of FIG.

[0058] 7, the induction coil 7A of the heating device 6A has a spiral portion 74 that spirally surrounds the jig 1B in the circumferential direction about the rotation axis X. The spiral portions 74 are provided with a phase shift in the circumferential direction about the rotation axis X, and are provided with a shift in position in the direction of the rotation axis X from the lower end 8a side to the upper end 8b side of the support portion 8.

[0059] The induction coil 7A is connected to a power supply 60 via wires 61 and 62 at one end 74a and the other end 74b of the spiral portion 74 in the circumferential direction around the rotation axis X. For example, the wire 61 is connected to a positive terminal (not shown) of the power supply 60, and the wire 62 is connected to a negative terminal (not shown) of the power supply 60. Therefore, a current I flows from the one end 74a of the spiral portion 74 to the other end 74b.

[0060] When a current I is applied to the induction coil 7A, the current flows in the spiral portion 74 in the circumferential direction around the rotation axis X (the direction of the arrow c in the figure). In this case, the direction of the magnetic field H formed around the spiral portion 74 is along the rotation axis X.

[0061] 8, in a cross-sectional view along the direction of the rotation axis X, the spiral portions 74 of the induction coil 7A are arranged at intervals in the direction of the rotation axis X. The spiral portions 74 located on one side of the rotation axis X and the spiral portions 74 located on the other side are shifted in position in the direction of the rotation axis X by half a pitch.

[0062] In a cross-sectional view along the direction of the rotation axis X, the direction of the magnetic field H formed around the spiral portion 74 is along the clockwise direction CW in the left region of the rotation axis X, and along the counterclockwise direction CCW in the right region of the rotation axis X.

[0063] In the second modification, the jig 1B is disposed between the stator core 50 and the spiral portion 74 of the induction coil 7A in the radial direction of the rotation axis X, thereby controlling the range of the magnetic field H.

[0064] As shown in Figure 8, the jig 1B is composed of a magnetic part 14 (magnetized area) made of a material that is magnetized by the action of a magnetic field, and a non-magnetic part 15 (non-magnetized area) made of a material that is not magnetized even when a magnetic field is applied.

[0065] The magnetic body part 14 has a cylindrical shape that surrounds the rotation axis X. The magnetic body part 14 has a through-hole 14c that penetrates the magnetic body part 14 in the radial direction of the rotation axis X. The through holes 14c are provided with a phase difference in the circumferential direction around the rotation axis X, and are formed in a spiral shape whose position in the direction of the rotation axis X changes from the lower end 14a to the upper end 14b of the magnetic material part 14. The phase of the through holes 14c approximately matches the phase of the spiral part 74 of the induction coil 7A. The through holes 14c are provided in a range from the lower end 14a to the upper end 14b of the magnetic material part 14 in the direction of the rotation axis X.

[0066] The non-magnetic material portion 15 is provided so as to close the through-hole 14c of the magnetic material portion 14. Therefore, the non-magnetic material portion 15 is also out of phase in the circumferential direction around the rotation axis X, and forms a spiral shape whose position in the direction of the rotation axis X changes from the lower end 14a side to the upper end 14b side of the magnetic material portion 14.

[0067] As shown in FIG. 8, in a cross-sectional view along the rotation axis X direction, in the jig 1B, the magnetic material portions 14 and the non-magnetic material portions 15 are arranged alternately in the rotation axis X direction. When the jig 1B is set in the holder 9, the spiral portion 74 and the non-magnetic portion 15 of the induction coil 7A are aligned on a straight line Lp (Lp1 to Lp7). The straight line Lp is a straight line that runs along the radial direction of the rotation axis X. When viewed from the current-carrying direction (the front-to-back direction on the paper in FIG. 8), the straight line Lp forms a straight line that passes through the spiral portion 74 and the stator core 50. As a result, when the jig 1B is viewed from the radial direction, the non-magnetic portion 15 overlaps with the spiral portion 74 of the induction coil 7A over the entire length in the direction along the spiral.

[0068] 8, when a current I (see FIG. 7) is applied to the induction coil 7A, a magnetic field H is formed around the spiral portion 74 in a direction along the rotation axis X. Specifically, the magnetic field H on one side (left side in the figure) of the rotation axis X is oriented in a clockwise direction CW, and the magnetic field H on the other side (right side in the figure) is oriented in a counterclockwise direction CCW.

[0069] In the second modification, the jig 1B is disposed between the spiral portion 74 of the induction coil 7A and the stator core 50 in the radial direction of the rotation axis X. The non-magnetic material portion 15 of the jig 1B is positioned at a position facing the spiral portion 74 in the radial direction.

[0070] As shown in the enlarged area of ​​Figure 8, when viewed from the spiral portion 74, the magnetic material portion 14 is located on one side and the other side of the non-magnetic material portion 15 in the direction along the magnetic field H (clockwise direction CW or counterclockwise direction CCW).

[0071] When the magnetic field H acts on the jig 1B from the spiral portion 74, the magnetic field lines forming the magnetic field H can pass through the magnetic material portion 14 but cannot pass through the non-magnetic material portion 15. Therefore, the magnetic material portion 14 is magnetized in a direction along the magnetic field H, but the non-magnetic material portion 15 is not magnetized. Therefore, the magnetic field H is formed so as to pass through the magnetic material portion 14 on one side (upstream side in the direction of the arrow), then cross the non-magnetic material portion 15 and head toward the magnetic material portion 14 on the other side (downstream side in the direction of the arrow).

[0072] As a result, the portion of the magnetic field H that straddles the non-magnetic material portion 15 is extended significantly toward the rotation axis X side, and acts on the yoke portion 51 side (outer periphery side) of the stator core 50. As a result, an eddy current is generated in the stator core 50, and the stator core 50 is heated.

[0073] Furthermore, in this embodiment, the spiral portions 74 of the induction coil 7A and the non-magnetic portions 15 of the jig 1B are each provided in plurality at intervals in the direction of the rotation axis X. Therefore, the magnetic field H acts on the stator core 50 from a plurality of positions in the direction of the rotation axis X (see FIG. 8). This makes it less likely that uneven heating will occur when the stator core 50 is heated.

[0074] The jig 1B according to the second modification has the following configuration. (3) The stator 5 having the stator core 50 is an armature. The stator core 50 has a ring shape when viewed from the direction of the rotation axis X. The induction coil 7A has a spiral portion 74 on the yoke portion 51 side (outer periphery side) of the stator core 50, which has a spiral shape with a phase shift in the circumferential direction around the rotation axis X as it moves from one side in the direction of the rotation axis X to the other side. The jig 1B has a cylindrical shape surrounding the rotation axis X. When viewed from the radial direction of the rotation axis X, the magnetic material portions 14 and the non-magnetic material portions 15 are provided alternately in the direction of the rotation axis X. When viewed from the radial direction, the non-magnetic material portion 15 is provided in a spiral shape that overlaps with the spiral portion 74 of the induction coil 7A.

[0075] When configured in this manner, the magnetic field H acting on the jig 1B from the induction coil 7A is formed across the non-magnetic material portion 15, from the magnetic material portion 14 on one side of the non-magnetic material portion 15 to the magnetic material portion 14 on the other side. As a result, the portion of the magnetic field H that straddles the non-magnetic material portion 15 is extended significantly toward the rotation axis X side, and acts on the stator core 50. As a result, an eddy current is generated in the stator core 50, and the stator core 50 is heated.

[0076] (Variations 3 and 4) In the above-described embodiment and modified examples 1 and 2, the stator core 50 is heated from the outer periphery side, but the present invention is not limited to this. For example, the stator core 50 may be heated from the inner periphery side.

[0077] Fig. 9 is a diagram illustrating a jig 1C according to Modification 3. Fig. 9 shows a cross section cut along the direction of the rotation axis X and passing through the teeth 52 of the stator core 50. Fig. 10 is a diagram illustrating a jig 1C according to Modification 3. Fig. 10 is a schematic diagram of a cross section taken along line AA in Fig. 9. Note that Fig. 10 simplifies the shape of the stator core 50. Also, Fig. 10 exaggerates the sizes of the non-magnetic material portion 17 and the straight portion 75 to make it easier to understand their positional relationship.

[0078] As shown in FIG. 9, a jig 1C and a heating device 6B according to the third modification are disposed on the inner diameter side of the stator 5. The heating device 6B has an induction coil 7B and a support part 8A that supports the induction coil 7B. The heating device 6B is set in a holder (not shown) with the cylindrical support part 8A oriented along the rotation axis X.

[0079] The induction coil 7B has a straight portion 75 oriented along the direction of the rotation axis X. The straight portion 75 has a length L75 in the direction of the rotation axis X that is longer than the length L50 of the stator core 50 (L75>L50). Therefore, when viewed from the radial direction, the stator core 50 overlaps with the straight portion 75 of the induction coil 7B over the entire length in the direction of the rotation axis X.

[0080] 10, a plurality of straight portions 75 are provided at intervals in the circumferential direction around the rotation axis X. The straight portions 75 are provided on an imaginary circle Im3 having the rotation axis X as its center. Although not shown in the figures, the straight portions 75 according to variant example 3 are connected at one end and the other end of adjacent straight portions 75 in the circumferential direction via arc-shaped portions, similar to the straight portion 71 described above (see Figure 1).

[0081] 9, the jig 1C has a cylindrical shape surrounding the rotation axis X. The jig 1C is fitted onto the support portion 8A on the inner circumferential side of the stator core 50. In the direction of the rotation axis X, the length L1C of the jig 1C is set to a length that is approximately aligned with the length L50 of the stator core 50 (L1C≈L50).

[0082] As shown in Figure 10, the jig 1C is composed of a magnetic part 16 (magnetized area) made of a material that is magnetized by the action of a magnetic field, and a non-magnetic part 17 (non-magnetized area) made of a material that is not magnetized even when a magnetic field is applied.

[0083] 10, the magnetic material portions 16 and the non-magnetic material portions 17 are formed in an arc shape having the same outer diameter and inner diameter. The jig 1C is formed in a ring shape along an imaginary circle Im4 centered on the rotation axis X by arranging the magnetic material portions 16 and the non-magnetic material portions 17 alternately in the circumferential direction around the rotation axis X.

[0084] The jig 1C is disposed in the space Ra between the stator core 50 and the induction coil 7B in the radial direction of the rotation axis X. When viewed from the direction of the rotation axis X, the non-magnetic material portion 17 of the jig 1C is positioned on a straight line Ln (Ln1 to Ln5). When viewed from the direction of the rotation axis X, the straight line Ln is a line connecting the rotation axis X and the straight line portion 75. The stator core 50 is located on the straight line Ln. In other words, when viewed from the current-carrying direction (the front-to-back direction on the paper in FIG. 10), the straight line Ln forms a line passing through the straight line portion 71 and the stator core 50. As a result, the non-magnetic portion 17 and the linear portion 75 of the induction coil 7B face each other in the radial direction of the rotation axis X.

[0085] Therefore, when a current is passed through the induction coil 7B, magnetic fields H aligned in the counterclockwise direction CCW and magnetic fields H aligned in the clockwise direction CW as viewed from the direction of the rotation axis X are alternately formed in the straight line portions 75 aligned in the circumferential direction around the rotation axis X.

[0086] As shown in Figure 10, when viewed from the straight portion 75, the magnetic material portion 16 is located on one side and the other side of the non-magnetic material portion 17 in the direction along the magnetic field H (clockwise direction CW or counterclockwise direction CCW). As a result, the portion of the magnetic field H that straddles the non-magnetic material portion 17 is extended significantly radially outward, and acts on the tooth portion 52 side (inner peripheral side) of the stator core 50. This generates an eddy current in the stator core 50, heating the stator core 50. The heat of the heated stator core 50 is ultimately transferred to the varnish V (see FIG. 9), causing the varnish V to harden.

[0087] The jig 1C according to the third modification has the following configuration. (2) The stator 5 having the stator core 50 is an armature. The stator core 50 has a ring shape when viewed from the direction of the rotation axis X. The straight portions 75 of the induction coil 7B are provided on the tooth portion 52 side (inner peripheral side) of the stator core 50, oriented along the direction of the rotation axis X, and are provided at intervals in the circumferential direction around the rotation axis X. The jig 1C has a cylindrical shape surrounding the rotation axis X. When viewed from the direction of the rotation axis X, the magnetic material portions 16 and the non-magnetic material portions 17 are provided alternately in the circumferential direction around the rotation axis X. When viewed from the direction of the rotation axis X, the non-magnetic material portion 17 is provided on a straight line Ln that connects the linear portion 75 of the induction coil 7B and the rotation axis X.

[0088] When configured in this manner, the magnetic field H acting on the jig 1C from the induction coil 7B is formed across the non-magnetic material portion 17, from the magnetic material portion 16 on one side of the non-magnetic material portion 17 to the magnetic material portion 16 on the other side (see Figure 10). As a result, the magnetic field H is extended significantly radially outward at the portion spanning the non-magnetic material portion 17, and acts on the stator core 50. As a result, an eddy current is generated in the stator core 50, and the stator core 50 is heated.

[0089] Fig. 11 is a diagram illustrating a jig 1D according to Modification 4. Fig. 11 shows a cross section cut along the direction of the rotation axis X by a plane passing through the teeth 52 of the stator core 50. Note that in Fig. 11, the sizes of the non-magnetic material portion 19 and the spiral portion 76 are exaggerated to make it easier to understand their positional relationship.

[0090] As shown in FIG. 11, a jig 1D and a heating device 6C according to the fourth modification are disposed on the inner diameter side of the stator 5. Support 8A of heating device 6C supports a spiral-shaped induction coil 7C. Induction coil 7C has a spiral portion 76 that spirally surrounds rotation axis X in the circumferential direction about rotation axis X. The spiral portions 76 are provided with a phase shift in the circumferential direction about rotation axis X, and are provided with a shift in position in the direction of rotation axis X as they move from the lower side to the upper side of support 8A.

[0091] The jig 1D has a cylindrical shape that surrounds the rotation axis X. The jig 1D is fitted onto the support portion 8A on the inner circumferential side of the stator core 50. The jig 1D is composed of a magnetic part 18 (magnetized area) made of a material that is magnetized by the action of a magnetic field, and a non-magnetic part 19 (non-magnetized area) made of a material that is not magnetized even when a magnetic field is applied.

[0092] The magnetic body portion 18 has a cylindrical shape that surrounds the rotation axis X. A through-hole 18c that penetrates the magnetic body portion 18 in the radial direction of the rotation axis X is formed in the magnetic body portion 18. The through holes 18c are provided with a phase difference in the circumferential direction around the rotation axis X, and are formed in a spiral shape whose position in the direction of the rotation axis X changes from the bottom to the top of the magnetic material part 18. The phase of the through holes 18c approximately matches the phase of the spiral part 76.

[0093] The non-magnetic material portion 19 is provided so as to close the through-hole 18c of the magnetic material portion 18. Therefore, the non-magnetic material portion 19 is also out of phase in the circumferential direction around the rotation axis X, and forms a spiral shape whose position in the direction of the rotation axis X changes from the lower side to the upper side of the magnetic material portion 18.

[0094] In a cross-sectional view taken along the rotation axis X, the jig 1D has magnetic material portions 18 and non-magnetic material portions 19 arranged alternately in the rotation axis X direction. In the jig 1D, the spiral portion 76 and the non-magnetic portion 19 of the induction coil 7C are aligned on a straight line Lq (Lq1 to Lq5) that is perpendicular to the rotation axis X. The straight line Lq is a straight line that runs along the radial direction of the rotation axis X. When viewed from the current-carrying direction (the front-to-back direction on the paper in FIG. 11), the straight line Lq forms a straight line that passes through the spiral portion 76 and the stator core 50. As a result, when viewed from the radial direction, the non-magnetic material portion 19 overlaps with the spiral portion 76 of the induction coil 7C over the entire length in the direction along the spiral.

[0095] 11, when a current is applied to the induction coil 7D, a magnetic field H is generated around the spiral portion 76, oriented along the rotation axis X. Specifically, the magnetic field H on one side (left side in the drawing) of the rotation axis X is oriented along the clockwise direction CW, and the magnetic field H on the other side (right side in the drawing) is oriented along the counterclockwise direction CCW.

[0096] When viewed from the spiral portion 76, the magnetic material portions 18 are located on one side and the other side of the non-magnetic material portion 19 in the direction along the magnetic field H (clockwise direction CW or counterclockwise direction CCW). When magnetic field H is applied to jig 1D from induction coil 7C, the magnetic field H's lines of force can pass through magnetic material portion 18 but cannot pass through non-magnetic material portion 19. As a result, magnetic material portion 18 is magnetized in a direction along magnetic field H, but non-magnetic material portion 19 is not magnetized. Therefore, magnetic field H is formed so as to pass through magnetic material portion 18 on one side (upstream side in the direction of the arrow), then cross non-magnetic material portion 19 and head toward magnetic material portion 18 on the other side (downstream side in the direction of the arrow).

[0097] As a result, the portion of the magnetic field H that straddles the non-magnetic material portion 19 is extended significantly radially outward, and acts on the tooth portion 52 side (inner peripheral side) of the stator core 50. This generates an eddy current in the stator core 50, heating the stator core 50. The heat of the heated stator core 50 is ultimately transferred to the varnish V, causing the varnish V to harden.

[0098] A jig 1D according to the fourth modification has the following configuration. (3) The stator 5 having the stator core 50 is an armature. The stator core 50 has a ring shape when viewed from the direction of the rotation axis X. The induction coil 7C has a spiral portion 76 on the tooth portion 52 side (inner peripheral side) of the stator core 50, which has a spiral shape with a phase shift in the circumferential direction around the rotation axis X as it moves from one side in the direction of the rotation axis X to the other side. The jig 1D has a cylindrical shape surrounding the rotation axis X. When viewed from the radial direction of the rotation axis X, the magnetic material portions 18 and the non-magnetic material portions 19 are alternately provided in the direction of the rotation axis X. When viewed from the radial direction, the non-magnetic material portion 19 is provided in a spiral shape that overlaps with the spiral portion 76 of the induction coil 7D.

[0099] When configured in this manner, the magnetic field H acting on the jig 1D from the induction coil 7C is formed across the non-magnetic material portion 19, from the magnetic material portion 18 on one side of the non-magnetic material portion 19 to the magnetic material portion 18 on the other side. As a result, the magnetic field H is extended significantly radially outward at the portion spanning the non-magnetic material portion 19, and acts on the stator core 50. As a result, an eddy current is generated in the stator core 50, and the stator core 50 is heated.

[0100] The above-described modifications 1 to 4 can be applied not only to the embodiment but also to combinations of the modifications with each other.

[0101] Although the embodiment of the present invention has been described above, the above embodiment merely shows one application example of the present invention, and the technical scope of the present invention is not intended to be limited to the specific configuration of the above embodiment. Appropriate modifications are possible within the scope of the technical concept of the invention. [Explanation of symbols]

[0102] 1, 1A, 1B, 1C, 1D Jig 5 Stator (armature) 6, 6A, 6B, 6C heating device 7, 7A, 7B, 7C induction coil 8, 8A support part 9 Holder 10 Magnetic body part (magnetized area) 11 Non-magnetic part (non-magnetized area) 12 Magnetic body part (magnetized area) 13 Through hole (non-magnetized area) 14 Magnetic body part (magnetized area) 14c through hole 15 Non-magnetic part (non-magnetized area) 16 Magnetic body part (magnetized area) 17 Non-magnetic part (non-magnetized area) 18 Magnetic body part (magnetized area) 18c through hole 19 Non-magnetic part (non-magnetized area) 50 Stator core (heated object) 51 Yoke part (outer periphery of armature) 52 Teeth (inner circumference side of armature) 71 Straight section 74 Spiral part 75 Straight section 76 Spiral part H magnetic field I current Lm straight line Ln Straight line Lp straight line Lq Line X rotation axis V Varnish

Claims

1. A jig used when inductively heating a heated object by energizing an induction coil, the jig is disposed between the induction coil and the object to be heated as viewed from the direction of current flow through the induction coil, the jig has a non-magnetized region and a magnetized region that can be magnetized by a magnetic field generated by energizing the induction coil, A jig in which, when viewed from the direction of current flow, the non-magnetized area is arranged on a straight line passing through the induction coil and the heated object, and the magnetized areas are provided on one side and the other side of the non-magnetized area in a direction along the magnetic field.

2. In claim 1, the heated object is an armature, The armature is ring-shaped when viewed from the direction of the rotation axis, the induction coil is provided on at least one of an outer circumferential side and an inner circumferential side of the armature, oriented along the direction of the rotation axis, and a plurality of induction coils are provided at intervals in the circumferential direction around the rotation axis, The jig has a cylindrical shape surrounding the rotation shaft, When viewed from the rotation axis direction, the magnetized regions and the non-magnetized regions are alternately provided in a circumferential direction around the rotation axis, When viewed from the direction of the rotation axis, the non-magnetized region is provided on the straight line connecting the induction coil and the rotation axis.

3. In claim 1, the heated object is an armature, The armature is ring-shaped when viewed from the direction of the rotation axis, the induction coil is provided on at least one of an outer circumferential side and an inner circumferential side of the armature in a spiral shape with a phase shift in a circumferential direction around the rotation axis as it moves from one side to the other side in the rotation axis direction, The jig has a cylindrical shape surrounding the rotation shaft, When viewed from a radial direction of the rotation shaft, the magnetized regions and the non-magnetized regions are alternately provided in the direction of the rotation shaft, When viewed from the radial direction, the non-magnetized region is provided in a spiral shape that overlaps with the induction coil.

4. In any one of claims 1 to 3, the magnetized region is made of a magnetic material, The non-magnetized region is made of a non-magnetic material.

5. In any one of claims 1 to 3, the magnetized region is made of a magnetic material, The non-magnetized region is composed of an air layer.

6. A method for heating the object to be heated using the jig according to claim 1, a positioning step of positioning the jig between the induction coil and the object to be heated; a positioning step of arranging the non-magnetized region on the straight line; a heating step of generating a magnetic field by passing current through the induction coil, and extending the magnetic field beyond the non-magnetized region toward the heated object, thereby heating the heated object.

Images