Magnet fixing method and magnet fixing device

Abstract

To be able to fix a magnet efficiently.SOLUTION: A fixation sheet 30 is adhered to one surface of a magnet 20 including a foam layer that foams by heating. A magnet fixing method comprises: a heating step of heating a rotor core 11; an insertion step of inserting the magnet 20 with the fixation sheet 30 adhered thereto into the uppermost slot 15 among multiple slots 15, in a state that an opening 15a of the slot 15 rotatably supports the rotor core 11 in a posture facing to the side using a rotary jig 40; and a fixing step of fixing the magnet 20 to the slot 15 by foaming the foam layer by heating. The insertion step includes: inserting the magnets 20 into all of the multiple slots 15 by repeatedly inserting the magnet 20 into the slot 15 with the fixation sheet 30 facing upward and rotating the rotor core 11.SELECTED DRAWING: Figure 5

Description

Technical Field

[0007] ,

[0001] The present invention relates to a magnet fixing method and a magnet fixing device.

Background Art

[0002] A rotor constituting a rotating electric machine includes a rotor core formed by laminating a plurality of iron core pieces, and permanent magnets (hereinafter referred to as magnets) that are inserted into a plurality of slots provided in the rotor core and fixed to the slots (see, for example, Patent Document 1).

[0003] The rotor described in Patent Document 1 includes a foamed adhesive sheet provided between the magnet and the inner surface of the slot. The foamed adhesive sheet has a foamed layer and an adhesive layer laminated on each other. The foamed layer is closely fixed to the magnet. The adhesive layer faces the inner surface of the slot.

[0004] In the method for manufacturing the rotor described in Patent Document 1, first, a magnet assembly in which a foamed adhesive sheet is closely fixed to a magnet is inserted into the slot. Then, by heating the magnet assembly, the foamed layer is foamed. As a result, the adhesive layer adheres closely to the slot, and the magnet is fixed to the slot.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, in the method for manufacturing the rotor described in Patent Document 1, in the step of inserting the magnet assembly into the slot, the adhesive layer is likely to come into contact with the inner surface of the slot. Therefore, there is room for improvement in improving the insertability of the magnet.

[0007] Furthermore, in the rotor manufacturing method described in Patent Document 1, the magnet assemblies are heated after being inserted into all the slots, so there is naturally a limit to how much the time from the start of inserting the magnet assemblies to the completion of fixing the magnets to the slots can be shortened. [Means for solving the problem]

[0008] A magnet fixing method for solving the above problems is a method for fixing magnets to a rotor core formed by stacking multiple iron core pieces, wherein magnets with fixing sheets attached are inserted into multiple slots and the magnets are fixed to the slots via the fixing sheets, the fixing sheets being attached to one surface of the magnets and including a foamed layer that foams when heated, the method comprising a heating step of heating the rotor core, an insertion step of inserting the magnets with the fixing sheets attached into the uppermost slot among the multiple slots while the rotor core is rotatably supported by a rotating jig in a position where the openings of the slots face sideways, and a fixing step of fixing the magnets to the slots by heating and foaming the foamed layer, wherein in the insertion step, the magnets are inserted into all of the multiple slots by repeatedly inserting the magnets into the slots with the fixing sheets facing upward and rotating the rotor core.

[0009] Furthermore, a magnet fixing device for solving the above problems is a magnet fixing device that inserts magnets to which fixing sheets are adhered into multiple slots of a rotor core formed by stacking multiple iron core pieces, and fixes the magnets to the slots via the fixing sheets, wherein the fixing sheets are adhered to one surface of the magnets and include a foamed layer that foams when heated, and comprises a heating device for heating the rotor core, a rotating jig for rotatably supporting the rotor core in a position where the openings of the slots face sideways, a guide member having a guide surface that extends along the axis of the rotor core and guides the magnets toward the slots by contacting the lower surface of the magnets, and a pushing mechanism for pushing the magnets on the guide surface toward the slots.

[0010] According to this method and configuration, when the rotor core is heated and supported by a rotating jig with the slot openings facing sideways, a magnet with a fixing sheet attached is inserted into the uppermost slot among the multiple slots. Subsequently, the foam layer is heated and expands. This creates an anchoring effect as the fixing sheet enters the gaps between the iron core pieces, thereby fixing the magnet to the slot.

[0011] In this method and configuration, the magnet is inserted into the slot with the fixing sheet facing upwards and the lower surface of the magnet in contact with the inner surface of the slot. This makes it less likely for the fixing sheet to come into contact with the heated inner surface of the slot. As a result, the foam layer does not begin to foam due to heat transfer from the inner surface of the slot during the insertion of the magnet. Therefore, the ease of inserting the magnet can be improved.

[0012] Furthermore, the above method allows for a shorter time from the start of the insertion process to the completion of the fixing process compared to the case where heating of the rotor core is started after inserting the magnet into the slot. Therefore, magnetic fixing can be performed efficiently. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1(a) is a front view of a rotor according to one embodiment, and Figure 1(b) is a side view of the same rotor. [Figure 2] Figure 2 is an enlarged view of the main part of Figure 1(a). [Figure 3] Figure 3 is a cross-sectional view of the fixed sheet that constitutes the rotor in Figure 1, before foaming. [Figure 4] Figure 4 is a schematic diagram showing the bonding process. [Figure 5] Figure 5 is a cross-sectional view showing the insertion process. [Figure 6] Figure 6 is a cross-sectional view along line 6-6 in Figure 5. [Figure 7]FIG. 7 is a cross-sectional view showing the state of the fixing step. [Figure 8] FIG. 8 is a view showing a guide member of a modified example, which is a cross-sectional view taken along line 8-8 of FIG. 5. [Figure 9] FIG. 9 is an enlarged cross-sectional view of the guide surface of the guide member of the modified example.

Mode for Carrying Out the Invention

[0014] Hereinafter, referring to FIGS. 1 to 7, an embodiment of a magnet fixing method and a magnet fixing device will be described. First, the configuration of the rotor 10 will be described.

[0015] Hereinafter, in the following, the axial direction, radial direction, and circumferential direction of the rotor 10 will be simply described as the axial direction, radial direction, and circumferential direction, respectively. <Rotor 10> As shown in FIG. 1(a), the rotor core 11 has a central hole 13 and a plurality of slots 15. The central hole 13 and the slots 15 penetrate the rotor core 11 in the axial direction.

[0016] In the central hole 13, a pair of keys 14 protruding inward in the radial direction are provided. The pair of keys 14 face each other in the radial direction. The plurality of slots 15 are provided side by side in a row in the circumferential direction. [[ID=3-]]

[0017] The plurality of slots 15 in the present embodiment include a slot 15A that extends so as to be located more radially outward toward the front side in the clockwise direction in a front view, and a slot 15B that extends so as to be located more radially inward toward the front side in the clockwise direction in a front view. In the present embodiment, one slot 15A and one slot 15B are provided alternately in the circumferential direction.

[0018] As shown in FIG. 1(b), the rotor 10 includes a rotor core 11 formed by laminating a plurality of core pieces 12. The core pieces 12 are made of electromagnetic steel sheets. The core piece 12 is provided with a dowel (not shown) that bulges out toward one side in the axial direction. The dowels of adjacent core pieces 12 in the stacking direction are crimped together, thereby joining the core pieces 12 together.

[0019] As shown in Figure 2, a magnet 20 with a fixing sheet 30 attached is inserted into each slot 15, and the magnet 20 is fixed to the slot 15 via the fixing sheet 30.

[0020] Magnet 20 is a rectangular prism-shaped permanent magnet. As shown in Figure 3, the fixing sheet 30 has an inner adhesive layer 31, a foam layer 32, and an outer adhesive layer 33.

[0021] The inner adhesive layer 31 is a layer that adheres to one surface of the magnet 20. The inner adhesive layer 31 has adhesive properties at room temperature. The inner adhesive layer 31 is formed of, for example, a thermoplastic resin. However, the inner adhesive layer 31 may also be formed of a thermosetting resin.

[0022] The foamed layer 32 is a layer laminated on the side of the inner adhesive layer 31 opposite to the magnet 20. The foamed layer 32 is formed of a foamed material that expands when heated. Urethane is preferred as the foamed material.

[0023] The outer adhesive layer 33 is a layer laminated on the side of the foam layer 32 opposite to the inner adhesive layer 31. The outer adhesive layer 33 exhibits its adhesive function when heated. The outer adhesive layer 33 is preferably made of a thermoplastic resin.

[0024] Next, the method for fixing the magnet 20 in this embodiment will be described. The method for fixing the magnet 20 includes an adhesive step, a heating step, an insertion step, and a fixing step. First, we will explain the bonding process in which the fixing sheet 30 is attached to one side of the magnet 20.

[0025] <Adhesion process> As shown in Figure 4, in the bonding process, the release sheet 93 of the fixed sheet roll 92 is intermittently wound up by the winding roller 90 via the roller 91, thereby forming a rectangular cut in the fixed sheet 30 being conveyed on the table 94.

[0026] The fixed sheet roll 92 is wound with a strip-shaped release sheet 93 and a strip-shaped fixed sheet 30 that is peelably bonded to the release sheet 93 via an inner adhesive layer 31. The cutter 95 is mounted above the base 94 so as to be able to move up and down. By lowering the cutter 95, it is pressed against the fixed sheet 30 on the base 94, thereby forming a cut in the fixed sheet 30.

[0027] Next, the portion of the fixing sheet 30 enclosed by the cuts is attracted by the suction plate 96, and the suction plate 96 is moved toward one side of the magnet 20 by a moving device (not shown). Then, the inner adhesive layer 31 of the fixing sheet 30 is pressed against one side of the magnet 20 by the moving device, thereby adhering the fixing sheet 30 to one side of the magnet 20.

[0028] <Heating process> In the heating process, the rotor core 11 is heated by a heating device. The heating device is a well-known configuration such as an electric furnace. The heating temperature of the rotor core 11 is, for example, above the temperature at which the foaming reaction of the foamed layer 32 of the fixed sheet 30 begins.

[0029] <Insertion Process> As shown in Figure 5, in the insertion process, first, the rotor core 11 is rotatably supported by the rotating jig 40 in a position where the opening 15a of the slot 15 faces sideways.

[0030] The rotating jig 40 comprises a main body 41, a plate 42 rotatably connected to the main body 41 and supporting one end face of the rotor core 11, and a post 43 protruding from the plate 42 and passing through the central hole 13 of the rotor core 11. The main body 41 is configured to rotate the plate 42 and the post 43 around the axis of the post 43.

[0031] It is preferable that the plate 42 is sized to contact the entire end face of one end face of the rotor core 11. The outer circumferential surface of the post 43 is provided with a pair of keyways 44 that engage with a pair of keys 14 of the rotor core 11 (see Figure 7).

[0032] Next, as shown in Figures 5 and 6, the magnet 20 with the fixing sheet 30 attached is inserted into the uppermost slot 15 of the multiple slots 15. As shown in Figure 6, in this embodiment, the magnets 20 to which the fixing sheet 30 is attached are inserted into the two uppermost slots 15A and 15B among the multiple slots 15.

[0033] Here, as shown in Figure 5, the magnet 20 is inserted using the guide member 60 and the push mechanism 65. In this embodiment, two magnets 20 are inserted using two guide members 60 and two push mechanisms 65 corresponding to the two slots 15A and 15B.

[0034] The guide member 60 has a guide surface 61. The guide surface 61 extends along the axis of the rotor core 11 and contacts the lower surface of the magnet 20, guiding the magnet 20 toward the uppermost slot 15 among the multiple slots 15.

[0035] In this embodiment, the tip surface of the guide member 60 is in contact with the end surface of the rotor core 11. The guide surface 61 is located on the same plane as the bottom surface 15b of the slot 15, that is, the inner surface that the magnet 20 inserted into the slot 15 makes contact with.

[0036] In this embodiment, the two uppermost slots 15A and 15B extend so that they are located radially inward as they approach each other in the circumferential direction (see Figure 2). As shown in Figure 6, the two guide surfaces 61 corresponding to the two slots 15A and 15B are positioned radially inward as they approach each other in the circumferential direction.

[0037] The guide member 60 has a pair of restricting walls 62 that rise from both ends of the guide surface 61 in the width direction W. The pair of restricting walls 62 are configured to restrict the movement of the magnet 20 in the width direction W by contacting the magnet 20.

[0038] Preferably, the pair of restrictive walls 62 are provided along the entire length of the guide member 60 in its extending direction. The guide member 60 is preferably made of a material with low thermal conductivity and low coefficient of linear expansion, such as ceramic.

[0039] The pushing mechanism 65 is configured to push the axial end face of the magnet 20 on the guide surface 61 toward the slot 15. In the insertion process, the magnets 20 are inserted into the slots 15 with the fixing sheet 30 facing upwards, and the rotor core 11 is rotated, and this process is repeated until magnets 20 are inserted into all of the multiple slots 15.

[0040] <Fixed process> As shown in Figure 7, in the fixing process, the magnet 20 is fixed to the slot 15 by heating the foam layer 32 to cause it to foam.

[0041] In this embodiment, after the insertion process, the rotor core 11 is rotated by the rotating jig 40 so as to press the fixing sheet 30 against the inner surface of the slot 15 by applying centrifugal force to each of the magnets 20.

[0042] Next, the operation of this embodiment will be described. The rotor core 11 is heated and supported by the rotating jig 40 in a position where the opening 15a of the slot 15 faces sideways. In this state, magnets 20 with fixing sheets 30 attached are inserted into the two uppermost slots 15 of the multiple slots 15. Subsequently, as the rotor core 11 is rotated by the rotating jig 40, centrifugal force acts on each of the magnets 20, pressing the fixing sheets 30 against the inner surface of the slots 15. Heat transfer from the inner surface of the slots 15 heats the outer adhesive layer 33 and the foam layer 32. As a result, the adhesive function of the outer adhesive layer 33 is activated and the foam layer 32 begins to foam. Then, an anchoring effect occurs as the fixing sheets 30 enter the gaps between the iron core pieces 12, fixing the magnets 20 to the slots 15.

[0043] In this embodiment, with the fixing sheet 30 facing upwards, the lower surface of the magnet 20 is in contact with the inner surface of the slot 15 as the magnet 20 is inserted into the slot 15. This makes it less likely for the fixing sheet 30 to come into contact with the heated inner surface of the slot 15. As a result, the foam layer 32 does not begin to foam due to heat transfer from the inner surface of the slot 15 during the insertion of the magnet 20. Therefore, the insertability of the magnet 20 can be improved.

[0044] Furthermore, according to this embodiment, the time required from the start of the insertion process to the completion of the fixing process can be shortened compared to the case where heating of the rotor core 11 is started after inserting the magnet 20 into the slot 15.

[0045] Next, the effects of this embodiment will be described. (1) In the insertion process, the magnets 20 are inserted into the slots 15 with the fixing sheet 30 facing upwards, and the rotor core 11 is rotated, and the magnets 20 are inserted into all of the multiple slots 15 by repeating this process.

[0046] This method allows for efficient magnetic fixation due to the aforementioned effects. (2) In the fixing process, after the insertion process, the rotor core 11 is rotated by the rotating jig 40 so as to press the fixing sheet 30 against the inner surface of the slot 15 by applying centrifugal force to each of the magnets 20.

[0047] With this method, the centrifugal force acting on each of the magnets 20 presses the fixing sheet 30 against the inner surface of the slot 15, and the foam layer 32 is heated by heat transfer from the inner surface of the slot 15, thereby promoting the foaming of the foam layer 32. Therefore, the fixing of the magnets 20 to the slot 15 can be completed early.

[0048] (3) The magnet fixing device includes a heating device for heating the rotor core 11 and a rotating jig 40 that rotatably supports the rotor core 11 in a position where the opening 15a of the slot 15 faces sideways. The magnet fixing device also includes a guide member 60 that extends along the axis of the rotor core 11 and has a guide surface 61 that contacts the lower surface of the magnet 20 to guide the magnet 20 toward the uppermost slot 15 of the multiple slots 15. The magnet fixing device also includes a pushing mechanism 65 that pushes the magnet 20 on the guide surface 61 toward the slot 15.

[0049] This configuration can produce the same effect as described in (1) above. (4) The guide member 60 has a pair of restricting walls 62 that rise from both ends in the width direction W of the guide surface 61.

[0050] With this configuration, the movement of the magnet 20 in the width direction W is restricted by the pair of restricting walls 62, making it easy to insert the magnet 20 into the slot 15 along the extending direction of the slot 15.

[0051] (5) The guide member 60 is made of ceramic. When inserting the magnet 20 with the tip surface of the guide member 60 in contact with the end surface of the rotor core 11, the guide member 60 is heated by heat transfer from the heated rotor core 11, and the foam layer 32 is heated via the magnet 20 in contact with the guide surface 61. In this case, the foam layer 32 may foam before or during the insertion of the magnet 20, which may impair the ease of inserting the magnet 20.

[0052] In this regard, with the above configuration, the thermal conductivity and coefficient of linear expansion of the guide member 60 are low, so the guide member 60 is less likely to expand due to heat transfer from the rotor core 11 to the guide member 60, and heat from the rotor core 11 is less likely to be transferred to the fixing sheet 30 via the magnet 20. As a result, the foam layer 32 is prevented from starting to foam due to heat transfer from the guide member 60 before or during the insertion of the magnet 20. Therefore, the insertability of the magnet 20 can be improved.

[0053] <Variation> This embodiment can be implemented with the following modifications. This embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0054] As shown in Figure 8, the guide member 60 may have two regulating pins 63 that can be inserted into two pocket portions 15c and 15d that form both ends of the slot 15 in the width direction W. The regulating pins 63 are configured to restrict the movement of the magnet 20 in the width direction W by contacting the magnet 20. The two regulating pins 63 are connected, for example, to the end face of the regulating wall 62.

[0055] The width W1 of the portion of slot 15 into which the magnet 20 can be inserted is set to be larger than the width W2 of the magnet 20. Therefore, there is a risk that the magnet 20 may tilt within slot 15. In this regard, with the above configuration, by advancing the guide member 60 toward the slot 15, the two regulating pins 63 enter the pocket portions 15c and 15d. When the magnet 20 is inserted in this state, the movement of the magnet 20 in the width direction W is restricted by the pair of regulating pins 63, thereby preventing the magnet 20 from tilting within the slot 15.

[0056] As shown in Figure 9, a recess 61a may be provided on the guide surface 61 of the guide member 60. In this case, since the guide surface 61 has a recess 61a, the contact area between the guide surface 61 and the magnet 20 becomes smaller.

[0057] As shown in Figure 9, by providing numerous recesses 61a, the sliding resistance when the magnet 20 slides on the guide surface 61 can be reduced, making it easier to insert the magnet 20 into the slot 15.

[0058] As mentioned above, when inserting the magnet 20 with the tip surface of the guide member 60 in contact with the end surface of the rotor core 11, the guide member 60 is heated by heat transfer from the heated rotor core 11, and the foam layer 32 is heated via the magnet 20 in contact with the guide surface 61. In this case, the foam layer 32 may foam before or during the insertion of the magnet 20, which may impair the ease of inserting the magnet 20.

[0059] In this regard, the above configuration reduces the contact area between the guide surface 61 and the magnet 20, thereby suppressing heat transfer from the guide surface 61 to the magnet 20. Consequently, the aforementioned problems can be suppressed.

[0060] • The pair of restrictive walls 62 can be omitted from the guide member 60. The tip of the guide surface 61 of the guide member 60 may be inserted into the inside of the slot 15.

[0061] After the insertion process, the rotor core 11 may not be rotated by the rotating jig 40. Even in this case, the foamed layer 32 can still be heated and foamed by the heat transmitted from the rotor core 11 through the magnet 20.

[0062] The fixing sheet 30 is not limited to having an outer adhesive layer 33, and the outer adhesive layer 33 can be omitted. Even in this case, the magnet 20 is fixed to the slot 15 by an anchoring effect created when the foam layer 32 fits into the gap between the iron core pieces 12.

[0063] The rotor core 11 may be supported by the rotating jig 40 in an inclined position such that the magnet 20 is positioned lower towards the front in the insertion direction. In this case, a portion of the gravitational force acting on the magnet 20 will act towards the front in the insertion direction, so the magnet 20 can be pushed into the slot 15 with a small force.

[0064] A rotating jig 40 that can expand or contract the outer diameter of the post 43 can also be used. When the rotor core 11 is heated, it expands due to thermal expansion, and the inner diameter of the central hole 13 becomes larger than at room temperature. As a result, after the fixing process, the central hole 13 of the rotor 10 shrinks due to cooling, which may make it difficult to remove the rotor 10 from the rotating jig 40. In this respect, with the above configuration, the outer diameter of the post 43 can be reduced, so the rotor 10 can be easily removed from the rotating jig 40.

[0065] <Note> The above embodiment includes the configuration described in the following appendix. [Note 1] A magnet fixing device for inserting magnets with fixing sheets attached into multiple slots of a rotor core formed by stacking multiple iron core pieces, and fixing the magnets to the slots via the fixing sheets, wherein the fixing sheets include a foamed layer that is attached to one surface of the magnet and foams when heated, and the magnet fixing device comprises a heating device for heating the rotor core, a rotating jig for rotatably supporting the rotor core in a position where the openings of the slots face sideways, a guide member having a guide surface that extends along the axis of the rotor core and contacts the lower surface of the magnet to guide the magnet toward the slot, and a pushing mechanism for pushing the magnet on the guide surface toward the slot.

[0066] [Note 2] The magnet fixing device according to Appendix 1, wherein the guide member has a pair of restricting walls that rise from both ends in the width direction of the guide surface, and the pair of restricting walls are configured to restrict the movement of the magnet in the width direction by contacting the magnet.

[0067] [Note 3] The magnet fixing device according to Appendix 1 or Appendix 2, wherein the guide member has two regulating pins that can be inserted into two pocket portions that form both ends of the slot in the width direction, and the regulating pins are configured to restrict the movement of the magnet in the width direction of the slot by contacting the magnet.

[0068] [Note 4] The magnet fixing device according to any one of the appendices 1 to 3, wherein the guide surface is provided with a recess. [Explanation of Symbols]

[0069] 10…Rota 11…Rotor core 12… Iron core piece 13...Center hole 14... Key 15, 15A, 15B… Slots 15a…Aperture 15b…Bottom surface 15c, 15d... Pocket section 20…Magnets 30…Fixed seat 31...Inner adhesive layer 32…Foam layer 33...Outer adhesive layer 40… Rotating jig 41...Main body 42... Plate 43…Post 44…Keyway 60… Guide component 61…Guidance surface 61a…recess 62... Barrier wall 63... Regulatory pin 65… Push-in mechanism 90... Retractable Roll 91...Laura 92...Fixed sheet roll 93...Release sheet 94 units 95...cutter 96...Adsorption plate

Claims

1. A magnet fixing method comprising inserting magnets, to which fixing sheets are adhered, into multiple slots of a rotor core formed by stacking multiple iron core pieces, and fixing the magnets to the slots via the fixing sheets, The fixing sheet is attached to one side of the magnet and includes a foamed layer that expands when heated. A heating step for heating the rotor core, With the rotor core rotatably supported by a rotating jig in a position where the opening of the slot faces sideways, the insertion step involves inserting the magnet to which the fixing sheet is attached into the uppermost slot among the plurality of slots; The process includes a fixing step of fixing the magnet to the slot by heating and foaming the foamed layer, In the insertion step, the magnet is inserted into the slot with the fixing sheet facing upwards via a guide member made of a material with lower thermal conductivity and coefficient of linear expansion than the rotor core, and the rotor core is rotated, and this process is repeated until the magnet is inserted into all of the multiple slots. Magnet fixing method.

2. In the fixing step, after the insertion step, the rotor core is rotated by the rotating jig so as to press the fixing sheet against the inner surface of the slot by applying centrifugal force to each of the magnets. The method for fixing a magnet according to claim 1.

3. A magnet fixing device that inserts magnets, to which fixing sheets are attached, into multiple slots of a rotor core formed by stacking multiple iron core pieces, and fixes the magnets to the slots via the fixing sheets, The fixing sheet is attached to one side of the magnet and includes a foamed layer that expands when heated. A heating device for heating the rotor core, A rotating jig that rotatably supports the rotor core in a position where the opening of the slot faces sideways, A guide member having a guide surface that extends along the axis of the rotor core and contacts the lower surface of the magnet to guide the magnet toward the slot, It comprises a pushing mechanism that pushes the magnet on the guide surface toward the slot, The guide member is formed of a material with lower thermal conductivity and coefficient of linear expansion than the rotor core. Magnet fixing device.

4. The guide member has a pair of restrictive walls that rise from both ends in the width direction of the guide surface, The pair of restricting walls are configured to restrict the movement of the magnet in the width direction by contacting the magnet. The magnet fixing device according to claim 3.

5. The guide member has two regulating pins that can be inserted into two pocket portions that form both ends of the slot in the width direction, The regulating pin is configured to restrict the movement of the magnet in the width direction of the slot by contacting the magnet. The magnet fixing device according to claim 3 or claim 4.

6. The guide surface is provided with a recess. The magnet fixing device according to claim 3.

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