Rotor and rotor manufacturing method

Abstract

A rotor comprises a rotor shaft (31), a magnet (32), and an ejection prevention member (34). The magnet (32) is disposed on the outer circumferential surface of the rotor shaft (31). The ejection prevention member (34) prevents the magnet (32) from being ejected radially outward from the rotor shaft (31). An end surface, of the magnet (32), positioned at an end in the axial direction of the rotor shaft (31) is defined as a magnet end surface (32b). A surface, of the rotor shaft (31), facing the magnet end surface (32b) is defined as a rotor-facing surface (312b). A clearance (CL) between the magnet end surface (32b) and the rotor-facing surface (312b) is filled with a filler (33). The ejection prevention member (34) is attached to the magnet (32) while covering a part of the rotor shaft (31) together with the filler (33).

Description

Rotor and Method for Manufacturing Rotor Cross - reference to Related Applications

[0001] This application is based on Japanese Patent Application No. 2024 - 200054 filed in Japan on November 15, 2024, and the contents of the base application are incorporated herein by reference in their entirety.

[0002] The disclosure in this specification relates to a rotor having a magnet and a method for manufacturing the rotor.

[0003] Patent Document 1 describes a rotor and a method for manufacturing a rotor equipped with a member for preventing the scattering of magnets. This rotor uses a ribbon - shaped material for the member for preventing scattering, and provides a rotor that covers the entire magnet by the upper - layer ribbon - shaped material closing the gaps between adjacent ribbon - shaped materials in the lower layer.

[0004] Japanese Unexamined Patent Application Publication No. 2023 - 151123

[0005] By the way, in order to obtain the performance of preventing the scattering of magnets that can withstand high - speed rotation of the rotor, it is desirable to wind around up to the axial end of the magnet. In addition, in order to obtain high anti - scattering performance, it is desirable to wind with high tension. Here, if the end face of the magnet with respect to the axial direction of the rotor shaft is the magnet end face, and the face of the rotor shaft that faces the magnet end face is the rotor facing face, there is a gap between the magnet end face and the rotor facing face. When the anti - scattering member winds around up to the axial end of the magnet, the anti - scattering member protrudes from the magnet end and reaches the above - mentioned gap. At that time, when winding with high tension, the anti - scattering member enters the above - mentioned gap, which causes distortion and breakage of the anti - scattering member.

[0006] If it is wound with low tension, even if the anti - scattering member reaches the above - mentioned gap, distortion and breakage can be suppressed. However, in order to obtain sufficient anti - scattering performance even with low tension, it is necessary to increase the number of windings, which will lead to an increase in the weight of the rotor in that case.

[0007] Furthermore, in order to rotate the anti-scattering member under high tension, it is necessary to suppress slippage at the beginning of the winding. Possible methods to suppress slippage include clamping and fixing the beginning of the winding with a jig, or providing a hook on the rotor shaft or the like and fixing the beginning of the winding to the hook. However, the former method requires processing such as cutting off the excess protruding end of the winding, which complicates the process. The latter method, on the other hand, results in a more complex rotor shape and increases the rotor weight.

[0008] One objective of the disclosure is to provide a lightweight rotor that can withstand high rotational speeds while achieving excellent scattering prevention performance. Another objective of the disclosure is to provide a simple method for manufacturing a lightweight rotor that can withstand high rotational speeds while achieving excellent scattering prevention performance.

[0009] To achieve the above objective, a rotor according to one aspect of the present disclosure is a rotor for a motor having a radial gap, comprising a rotor shaft, a magnet disposed on the outer circumferential surface of the rotor shaft, and a scattering prevention member mounted so as to orbit the rotor shaft along the outer circumferential surface of the magnet to prevent the magnet from scattering radially outward from the rotor shaft, wherein the end face of the magnet located at the axial end of the rotor shaft is the magnet end face, the surface of the rotor shaft facing the magnet end face is the rotor facing surface, a filler material is filled in the gap between the magnet end face and the rotor facing surface, and the scattering prevention member is mounted on the magnet in a state that it covers a part of the rotor shaft together with the filler material.

[0010] According to the disclosed rotor, even if the anti-scattering member is routed around the axial end of the magnet and extends beyond the magnet end, the filler material prevents the anti-scattering member from getting into gaps. Therefore, even when the anti-scattering member is routed under high tension, distortion and damage to the anti-scattering member are suppressed. Furthermore, since it can cover the magnet end, high anti-scattering performance can be obtained. Moreover, sufficient anti-scattering performance can be obtained with fewer rotations compared to when it is routed under low tension. As a result, it is possible to achieve lightweight anti-scattering performance that can withstand high rotations.

[0011] Furthermore, in order to achieve the above objective, a method for manufacturing a rotor according to one aspect of the present disclosure comprises a rotor shaft, magnets arranged on the outer circumferential surface of the rotor shaft, and a scattering prevention member mounted so as to circumferentially wrap around the rotor shaft along the outer circumferential surface of the magnets, thereby preventing the magnets from scattering radially outward from the rotor shaft, the method comprising: a first step of starting to wind the scattering prevention member by circumferentially wrapping it parallel to the circumferential direction with a tension less than a predetermined tension; and a second step performed following the first step of spirally wrapping the scattering prevention member along the circumferential direction with an axial inclination at a tension greater than a predetermined tension.

[0012] According to the disclosed rotor manufacturing method, the first step increases the frictional force between the rotor shaft or magnet and the anti-scattering member. This suppresses slippage at the beginning of the winding. Therefore, in the subsequent second step, the anti-scattering member can be rotated around the magnet with high tension without the use of jigs or hooks. In other words, a simple rotor manufacturing method is provided that achieves lightweight anti-scattering performance that can withstand high rotations.

[0013] The reference numbers in parentheses above are merely examples of correspondences with specific configurations in the embodiments described later, and do not limit the technical scope in any way.

[0014] This figure shows the configuration of the eVTOL in the first embodiment. This is a cross-sectional view of the motor shown in Figure 1. This is a perspective view of the rotor according to the first embodiment. This figure shows a cross-section of the rotor according to the first embodiment that includes the rotation axis Cm. This is a flowchart showing the procedure for circling the anti-scattering member around the rotor according to the first embodiment. This is a plan view of the rotor according to the first embodiment before the anti-scattering member is circulated around it. This is a plan view of the rotor according to the first embodiment showing the work status of circling the anti-scattering member. This is a plan view of the rotor according to the first embodiment showing the work status when the circulation of the anti-scattering member has progressed further from Figure 6. This is a plan view of the rotor according to the first embodiment after the circulation of the anti-scattering member has been completed. This figure explains the folding position of the anti-scattering member circling around the rotor according to the first embodiment. This is a graph showing the folding position of each layer of the anti-scattering member circling around the rotor according to the first embodiment. This figure shows a cross-section of the rotor according to the second embodiment that includes the rotation axis Cm. This figure shows a cross-section of the rotor according to the third embodiment that includes the rotation axis Cm. This figure shows a cross-section of the rotor according to the fourth embodiment that includes the rotation axis Cm.

[0015] (First Embodiment) The electric aircraft shown in Figure 1 is a vertical take-off and landing aircraft called eVTOL2, which is an electric aircraft capable of taking off and landing vertically. eVTOL is an abbreviation for electric Vertical Take-Off and Landing aircraft. eVTOL2 is a manned aircraft that carries a crew. eVTOL2 comprises an airframe 3, a battery 4, a propeller 6, and an EPU 7, etc.

[0016] The aircraft 3 has a main body 3a and glider wings 3b. Multiple propellers 6 are attached to the glider wings 3b, generating lift and thrust for the aircraft 3. The EPU 7 is an electric propulsion system that rotates the propellers 6. EPU is an abbreviation for Electric Propulsion Unit. The EPU 7 has a motor 7m and a motor control unit. In the following description, the motor control unit will be referred to as MCU 7i. MCU is an abbreviation for Motor Control Unit.

[0017] Each of the multiple EPUs 7 is individually provided for each of the multiple propellers 6. The EPUs 7 are arranged along the propeller axis on the propellers 6. All of the multiple EPUs 7 are fixed to the airframe 3. The EPUs 7 rotatably support the propellers 6. The battery 4 is mounted on the airframe 3. The battery 4 supplies DC power to the multiple EPUs 7. The battery 4 has a rechargeable secondary battery.

[0018] The propeller 6 and motor 7m are connected by a rotating shaft 8. The propeller 6 and motor 7m are aligned along the rotating shaft Cm so that the rotating shaft Cm of the motor 7m coincides with the rotating shaft Cm of the propeller 6. The EPU 7 may also include a reduction gear to reduce the rotation of the motor 7m. The MCU 7i is aligned along the rotating shaft Cm together with the propeller 6 and motor 7m. In the example shown in Figure 1, the MCU 7i is located on the opposite side of the propeller 6 from the motor 7m. The MCU 7i may also be located between the motor 7m and the propeller 6.

[0019] The MCU 7i includes an inverter circuit, a control circuit, and an inverter housing 7a. The inverter housing 7a houses the inverter circuit and the control circuit inside. The inverter circuit converts the DC power supplied from the battery 4 into AC power and supplies it to the motor 7m. The control circuit controls the operation of the inverter circuit in response to commands from the flight control device.

[0020] As shown in Figure 2, the motor 7m includes a stator 20 and a rotor 30, etc.

[0021] The stator 20 has a core and windings (not shown). Windings are wound around the core. The windings generate magnetic flux when current is passed through them. The core is made of a material with high magnetic permeability and has a cylindrical shape extending in the direction of the rotation axis Cm. The magnetic flux generated from the windings is concentrated by the core. The MCU 7i controls the on / off switching of the current to the windings, thereby causing the stator 20 to generate a rotating magnetic field.

[0022] The rotor 30 is a radial gap type, forming a radial gap G with respect to the stator 20. A rotating shaft 8 is connected to the rotor 30. As a result, the propeller 6 rotates together with the rotor 30. The rotor in this embodiment is a high-speed rotation specification with a maximum operating speed of 12,000 [rpm] or more. As shown in Figure 3, the rotor 30 has a rotor shaft 31, a magnet 32, a filler material 33, and a scattering prevention member 34.

[0023] The rotor shaft 31 has a cylindrical base 311, a flange 312 (see Figure 4), and a projection 313. The rotating shaft 8 is connected to the rotor shaft 31. The rotor shaft 31 is made of metal. However, the rotor shaft 31 may be made of resin.

[0024] The cylindrical base 311 is cylindrical in shape and extends in the direction of the rotation axis Cm. The flange 312 is formed in a disc shape at both axial ends of the cylindrical base 311. As shown in Figure 4, the outer circumferential surface of the flange 312 is located radially outward from the outer circumferential surface 311a of the cylindrical base 311.

[0025] The projection 313 has a shape that protrudes radially outward from the outer circumferential surface of the flange 312. This projection 313 is located on the axial side opposite the filler 33 with respect to the rotor-facing surface 312b, which will be described later. The projection 313 has an annular shape that extends in the circumferential direction of the flange 312. As shown in Figure 4, in this embodiment, the projection 313 is formed at a position adjacent to the filler 33 in the axial direction and has a tapered shape that gradually increases in diameter as it moves away from the filler 33. In this embodiment, the projection 313 has an outermost diameter portion 313a and a tapered surface 313b. Note that although the outermost diameter portion 313a of the projection 313 is linearly pointed in Figure 4, it may be a flat surface or a curved surface.

[0026] The magnet 32 ​​is a permanent magnet. The magnet 32 ​​has an outer circumferential surface 32a and a magnet end face 32b. The magnet 32 ​​is positioned on the outer circumferential surface 311a of the cylindrical base 311 and sandwiched between two flanges 312. The magnet end face 32b is the end face of the magnet 32 ​​located at the axial end of the rotor shaft 31. There is a gap CL between the rotor-facing surface 312b, which is the surface of the flange 312 that faces the magnet end face 32b, and the magnet end face 32b. This gap CL is provided to absorb tolerances in the axial dimension of the magnet 32 ​​or in the distance between the pair of flanges 312. As shown in Figure 3, a plurality of magnets 32 are arranged in a line in the circumferential direction of the cylindrical base 311. The magnets 32 are arranged in a Halbach arrangement to concentrate the magnetic field toward the stator 20.

[0027] The magnet 32 ​​can be said to be attached to the outer surface of the rotor shaft 31. In other words, the motor 7m is a surface permanent magnet motor (SPM motor). SPM is an abbreviation for Surface Permanent Magnet.

[0028] As shown in Figures 4 and 6, the filler material 33 is filled into the gap CL. In this embodiment, the outer surface 33a of the filler material 33 and the outer surface 32a of the magnet 32 ​​are located on the same plane. The filler material 33 may be filled into only a part of the gap CL, or it may be filled into the entire gap CL. In this embodiment, the filler material 33 is filled to a thickness that can withstand the tension of the scattering prevention member 34. Adhesive is used in the filler material 33. The adhesive has sufficient strength to prevent the fibers constituting the scattering prevention member 34, which will be described later, from falling in. The filler material 33 is applied to the gap CL by an assembly worker and then hardened over time.

[0029] The scattering prevention member 34 is mounted so as to circle the rotor shaft 31 along the outer circumferential surfaces 32a of the multiple magnets 32. The scattering prevention member 34 presses the magnets 32 against the outer circumferential surface 311a of the cylindrical base portion 311. In this way, the scattering prevention member 34 prevents the magnets 32 from scattering radially outward from the rotor shaft 31. The scattering prevention member 34 is mounted on the magnets 32 together with the filler material 33, covering a portion of the rotor shaft 31. In this embodiment, the scattering prevention member 34 covers the tapered surface 313b of the protruding portion 313 of the rotor shaft 31.

[0030] The shatterproof member 34 wraps around the magnet 32 ​​in multiple layers. Furthermore, the shatterproof member 34 covers the entire outer surface 32a of the magnet 32. As a result, the outer surface 32a of the magnet 32 ​​is not exposed to the surface. The shatterproof member 34 is made of a single ribbon-shaped sheet. The width of the ribbon-shaped sheet is set to be smaller than the axial length of the magnet 32. The thickness of the ribbon-shaped sheet in this embodiment is 90 μm to 110 μm. Furthermore, the ribbon-shaped sheet is made of a material with tackiness.

[0031] The anti-scattering member 34 of this embodiment uses a composite reinforcing material made by impregnating a fibrous material with resin. Specific examples of fibrous materials include carbon fibers and glass fibers. Specific examples of resins used for impregnation include thermosetting resins such as epoxy resins and thermoplastic resins such as polyamides and polyimides. For example, the anti-scattering member 34 uses a prepreg of carbon fiber reinforced plastic (hereinafter referred to as CFRP). CFRP is an abbreviation for Carbon Fiber Reinforced Plastics. Prepreg is a pre-impregnated material, which is made by impregnating reinforcing fibers with resin. The tackiness is achieved by the above-mentioned resin.

[0032] Furthermore, the scattering prevention member 34 is mounted such that its outermost diameter portion 34g is radially inward from the outermost diameter portion 313a of the protruding portion 313. The ribbon-shaped sheet may be made of a tacky material other than CFRP prepreg. The thickness of the ribbon-shaped sheet may be less than 90 μm or thicker than 110 μm. In addition, the scattering prevention member 34 may be in the form of a rope instead of a sheet.

[0033] Next, the manufacturing method of the rotor 30 described above will be explained. First, a plurality of magnets 32 are placed at predetermined positions on the rotor shaft 31. Specifically, the magnets 32 are fitted between a pair of flange portions 312. Next, a filler material 33 is applied to the gap CL between the flange portions 312 and the magnets 32. After that, after waiting for the filler material 33 to harden sufficiently, the scattering prevention member 34 is wrapped around the outer surface of the magnets 32 and attached. Specifically, using a winding device (not shown), the scattering prevention member 34 is pulled and tensioned as shown by the arrow in Figure 7, and wound around the rotor shaft 31 along the outer surface of the magnets 32.

[0034] The method for manufacturing the rotor, specifically the method for attaching the scattering prevention member 34, will be explained below using Figure 5. Figure 5 is a flowchart showing the steps of the work performed by the worker.

[0035] The scattering prevention member 34 is installed by a method including the following first step S10, second step S20, folding parallel step S31, folding spiral step S32, judgment step S33, and third step S40. The first step S10 is the step of starting to wind the scattering prevention member 34. As shown in Figure 7, in the first step S10, the scattering prevention member 34 is wound parallel to the circumferential direction. In the first step S10, a part of the scattering prevention member 34 functions as the starting parallel portion 34a. The starting parallel portion 34a is located in a position that contacts the magnet 32, the filler material 33, and the tapered surface 313b. In this embodiment, the circumference length of the starting parallel portion 34a is one turn or more. Also, tension is applied to the scattering prevention member 34 in the first step S10. The under tensioned scattering prevention member 34 is wound in a state of elastic deformation in the tensile direction. The position of the starting parallel portion 34a may be a position that contacts both the filler 33 and the magnet 32, or a position that contacts only the magnet 32. Furthermore, the anti-scattering member 34 that is tensioned in the first step S10 may undergo elastic deformation accompanied by plastic deformation. Alternatively, the tension applied to the anti-scattering member 34 in the first step S10 may be 0 [N]. Additionally, the circumference length of the starting parallel portion 34a may be less than one turn.

[0036] The second step S20 is performed following the first step S10. The second step S20 is a process of spirally winding the anti-scattering member 34 so that it is inclined axially along the circumferential direction. As shown in Figure 7, as a result of the second step, a part of the anti-scattering member 34 functions as a spiral portion 34b. In the second step S20, the anti-scattering member 34 is spirally wound so that it does not overlap with adjacent anti-scattering member 34 in the width direction within the same circumferential layer. The gap between the spirals that is created here is smaller than the width of the anti-scattering member 34. The angle of inclination that the anti-scattering member 34 has with respect to the axial direction of the rotor shaft 31 is constant within the same circumferential layer. Therefore, the gap between the spirals is the same width within the same circumferential layer. In the second step S20, a higher tension is applied to the anti-scattering member 34 than in the first step S10. The tensioned anti-scattering member 34 is wound in a state of elastic deformation in the tensile direction. The gap between the helices may be absent or may be larger than the width of the anti-scattering member 34. Alternatively, the anti-scattering member 34 may overlap with adjacent anti-scattering members 34 in the width direction within the same circumferential layer. Furthermore, the anti-scattering member 34 that is tensioned in the second step S20 may undergo elastic deformation accompanied by plastic deformation.

[0037] The folding parallel process S31 is a process in which the material, after being wound spirally in the second process S20, is wound parallel to the circumferential direction. As shown in Figures 7 and 8, in the folding parallel process S31, a part of the anti-scattering member 34 functions as a parallel portion 34c at one end and a parallel portion 34e at the other end. In Figure 8, the starting parallel portion 34a and the filler material 33 are omitted. In this embodiment, the parallel portion 34c at one end and the parallel portion 34e at the other end are in contact with the tapered surface 313b. In the folding parallel process S31, the same tension as in the second process S20 is applied to the anti-scattering member 34. "Same" here means the same within a range that includes manufacturing variations. The anti-scattering member 34, under tension, is wound in a state of elastic deformation in the tensile direction. As a result, the anti-scattering member 34 exhibits an elastic force that tries to shrink in a direction that reduces the diameter of the rotor shaft 31. This elastic force acts as abdominal pressure to press the magnet 32 ​​against the rotor shaft 31. The circumference length L1 of the parallel section 34c at one end and the circumference length L2 of the parallel section 34e at the other end are each less than one full rotation.

[0038] Note that the parallel portion 34c at one end and the parallel portion 34e at the other end do not have to be in contact with the tapered surface 313b. For example, the parallel portion 34c at one end and the parallel portion 34e at the other end may be in contact with the filler material 33, or they may be in contact with the already completed parallel portion 34c at one end and the parallel portion 34e at the other end. Also, the circumference length L1 of the parallel portion 34c at one end and the circumference length L2 of the parallel portion 34e at the other end may be one or more turns. Furthermore, the tension applied to the anti-scattering member 34 in the folding parallel process S31 may be less than or greater than the tension applied in the second process S20. The anti-scattering member 34 that has been tensioned in the folding parallel process S31 may undergo elastic deformation accompanied by plastic deformation.

[0039] The folding spiral process S32 is a process in which the part that has circled parallel to the part that has circled in parallel by the folding parallel process S31 is folded back and the part that has already circled the part of the anti-scattering member 34 is overlapped and circled in a spiral shape. As shown in Figure 8, the folding spiral process S32 forms a folded spiral portion 34d in the anti-scattering member 34. The folding spiral process S32 is performed in the same manner as the second process S20 described above. That is, the angle of inclination that the anti-scattering member 34 has with respect to the axial direction of the rotor shaft 31 is constant in the same circumferential layer. Here, the absolute value of the angle of inclination that the anti-scattering member 34 has with respect to the axial direction of the rotor shaft 31 is constant in the second process S20 and the folding spiral process S32. When the direction of spiral advancement is reversed, the sign of the angle of inclination is reversed. Other conditions are the same as in the second process S20.

[0040] The determination step S33 is a step in which it is determined whether the number of circulating layers has reached a predetermined number after the folding spiral step S32. If it is determined in the determination step S33 that the number of circulating layers has reached a predetermined number, the process proceeds to the third step S40. On the other hand, if it is determined that the predetermined number has not been reached, the process proceeds again to the folding parallel step S31. By repeating this process, the anti-scattering member 34 is wrapped in multiple layers around the outer circumferential surface 32a of the magnet 32 ​​using a single ribbon-shaped sheet. In this embodiment, the determination is made with a predetermined number of 9 layers. That is, in this embodiment, the anti-scattering member 34 is wrapped around the outer circumferential surface 32a of the magnet 32 ​​in a total of 9 layers. At this time, a total of 8 parallel portions 34c on one end and 34e on the other end are formed on the anti-scattering member 34.

[0041] In this embodiment, multiple parallel portions 34c at one end and parallel portions 34e at the other end are evenly offset in each layer along the circumferential direction. As mentioned above, the winding pitch of the helical portion 34b and the folded helical portion 34d are the same. Also, the circumferential length L1 of the parallel portion 34c at one end and the circumferential length L2 of the parallel portion 34e at the other end are the same. Furthermore, the following points are the same regardless of the layer. That is, the axial length of the anti-scattering member 34, the winding pitch of the helical portion 34b and the folded helical portion 34d, and the circumferential lengths L1 and L2 are the same regardless of the layer. Here, the axial length of the anti-scattering member 34 refers to the axial length of the portion that covers the rotor shaft 31, not the circumferential length of the anti-scattering member 34.

[0042] Here, the eight circles in Figure 10 represent the end positions of the parallel section 34c at one end and the parallel section 34e at the other end. The end positions become the folding positions of the anti-scattering member 34. The Roman numerals inside the circles indicate which layer the folding position is. The circles with dot hatching in Figure 10 represent the parallel section 34c at one end. The plain circles represent the parallel section 34e at the other end. Figure 11 is a graph showing the circumferential angle from a certain point for each layer's folding position, i.e., the above-mentioned end position. In this embodiment, the folding positions are shifted by 135° for each layer. Therefore, the eight folding positions are evenly shifted for each layer.

[0043] As described above, in order to ensure that the folding positions are evenly offset for each layer, it is necessary to adjust the circumference lengths L1 and L2 to appropriate lengths. The circumference lengths L1 and L2 adjusted in this way are calculated based on the axial length of the anti-scattering member 34 and the winding pitch of the helical portion 34b and the folded helical portion 34d. This calculation assumes that the axial length of the anti-scattering member 34, the winding pitch, and the circumference lengths L1 and L2 are the same for all layers.

[0044] The third step S40 is a step of finishing winding the scattering prevention member 34. As shown in FIG. 9, in the third step S40, after the scattering prevention member 34 is wound around parallel to the circumferential direction, the winding is stopped. By the third step S40, a part of the scattering prevention member 34 functions as a wound end parallel portion 34f. In the present embodiment, the circumferential length of the wound end parallel portion 34f is one turn or more. Further, in the third step S40, the same tension as that in the second step S20 is applied to the scattering prevention member 34. Here, the term "the same" means the same within the range including manufacturing variations. The scattering prevention member 34 to which the tension is applied is wound in a state of being elastically deformed in the tensile direction. Note that the circumferential length of the wound end parallel portion 34f may be less than one turn. Also, the tension applied to the scattering prevention member 34 in the third step S40 may be smaller or larger than the tension applied in the second step S20. Further, the scattering prevention member 34 to which the tension is applied in the third step S40 may be elastically deformed with plastic deformation.

[0045] After the third step S40, the end of the scattering prevention member 34 is cut. The resin constituting the scattering prevention member 34 is a thermosetting resin and is cured by being heated after cutting. Here, the portion of the scattering prevention member 34 that is wound in the third step S40 is wound overlapping the already wound portion. There may be a portion wound in a spiral or a portion wound in parallel below the portion wound in the third step S40. In the present embodiment, the wound end parallel portion 34f contacts the tapered surface 313b in addition to the already wound portion. Note that the wound end parallel portion 34f may be at a position where it contacts only the already wound scattering prevention member 34 without contacting the tapered surface 313b.

[0046] Incidentally, in the present embodiment, the entire outer peripheral surface 32a of the magnet 32 is covered with the scattering prevention member 34. However, a part of the magnet 32 may be exposed from the scattering prevention member 34. When exposed in this way, the following modified examples can be given for the wound end parallel portion 34f. That is, the wound end parallel portion 34f may contact any one or more of the magnet 32, the filler 33, and the already wound scattering prevention member 34.

[0047] <Function and Effect in the First Embodiment>In the rotor 30 according to the present embodiment, the gap CL between the magnet end face 32b and the rotor facing face 312b is filled with a filler 33. By the way, in order to obtain the performance of preventing the magnet from scattering that can withstand high-speed rotation of the rotor, it is desirable that the scattering prevention member 34 circulates to the axial end portion of the magnet 32. In addition, in order to obtain high scattering prevention performance, it is desirable that the scattering prevention member 34 circulates at a high tension. However, if the gap CL is not filled with the filler 33 contrary to the present embodiment, the scattering prevention member 34 enters the gap CL. In particular, when the scattering prevention member is made of a fibrous material, the fibers are likely to enter the gap CL. As a result, the scattering prevention member 34 may be distorted or damaged. On the other hand, in the present embodiment, the gap CL is filled with the filler 33. Therefore, even if the scattering prevention member 34 circulates at a high tension to the axial end portion of the magnet 32, distortion and breakage of the scattering prevention member 34 can be suppressed. That is, since the scattering prevention member 34 can circulate at a high tension to the axial end portion of the magnet, high scattering prevention performance can be obtained. Furthermore, by circulating at a high tension, high scattering prevention performance can be obtained with a smaller number of circulations compared to the case of circulating at a low tension. As a result, the weight reduction of the rotor is also possible.

[0048] Further, in the present embodiment, the scattering prevention member 34 is attached to the magnet 32 in a state of covering a part of the rotor shaft 31 together with the filler 33. Therefore, the axial end portion of the magnet 32 can be reliably covered. Thus, high scattering prevention performance can be obtained. Also, in the present embodiment, the scattering prevention member 34 covers the entire outer peripheral surface 32a of the magnet 32. That is, the outer peripheral surface 32a of the magnet 32 is not exposed on the surface. With these structures, it is also possible to suppress the magnet 32 from being damaged and the magnet 32 particles from scattering, or the filler 33 from scattering. Therefore, the scattering prevention performance that can withstand high rotation can be obtained.

[0049] Furthermore, in this embodiment, the outer surface 33a of the filler material 33 and the outer surface 32a of the magnet 32 ​​are on the same plane. As a result, there are no irregularities between the outer surface 33a of the filler material 33 and the outer surface 32a of the magnet 32. Therefore, the effect of suppressing distortion and damage of the scattering prevention member 34 can be further enhanced.

[0050] Furthermore, in this embodiment, the anti-scattering member 34 is arranged in multiple layers around the magnet 32. This increases the force with which the anti-scattering member 34 presses the magnet 32 ​​against the outer circumferential surface 311a of the cylindrical base 311. As a result, higher anti-scattering performance can be obtained. In other words, anti-scattering performance that can withstand high rotations can be obtained.

[0051] Furthermore, in this embodiment, a protruding portion 313 is formed on the rotor shaft 31 on the side of the rotor facing surface 312b that is opposite to the filler material 33, projecting radially outward. The inventors have found that when the anti-scattering member 34 is circulated in multiple layers, the following phenomenon occurs. That is, when the anti-scattering member 34 is circulated under high tension to improve the anti-scattering performance, the anti-scattering member 34 is compressed radially. Consequently, the anti-scattering member 34 may shift and spread axially over time. As a result, the anti-scattering performance deteriorates. In view of this, the rotor shaft 31 of this embodiment has a protruding portion 313 that projects radially outward. Therefore, the spreading of the anti-scattering member 34 is suppressed by the protruding portion 313. Thus, it is possible to suppress the deterioration of the anti-scattering performance, which has been improved by circulating it under high tension, over time.

[0052] Furthermore, in this embodiment, the protrusion 313 has a tapered shape that gradually widens in diameter as it moves away from the filler material 33. Here, when the anti-scattering member 34 is rotated around the rotor shaft 31, a part of the anti-scattering member 34 may come into contact with the protrusion 313. In that case, if the protrusion 313 is angular, there is a concern that the anti-scattering member 34 may be damaged. To address this concern, if the protrusion 313 is formed at a position sufficiently far from the filler material 33 so that the anti-scattering member 34 does not come into contact with the protrusion 313 during rotation, the size of the rotor shaft 31 will increase in the axial direction. Considering this point, in this embodiment, since the protrusion 313 has a tapered shape, the concern of damage during rotation can be suppressed. Therefore, the protrusion 313 can be formed at a position close to the filler material 33, and the axial increase in the size of the rotor shaft 31 can also be suppressed.

[0053] Furthermore, in this embodiment, the protrusion 313 is formed adjacent to the filler material 33, and a part of the scattering prevention member 34 is in contact with the protrusion 313. This helps to suppress the axial enlargement of the rotor shaft 31 as described above.

[0054] Furthermore, in this embodiment, the outermost diameter portion 34g of the anti-scattering member 34 is located radially inward from the outermost diameter portion 313a of the protruding portion 313. If the outermost diameter portion 34g of the anti-scattering member 34 is located outside the outermost diameter portion 313a of the protruding portion 313, the anti-scattering member 34 may overlap with the outermost diameter portion 313a of the protruding portion 313. This could cause damage to the anti-scattering member 34 pressed against the outermost diameter portion 313a of the protruding portion 313. Also, if the magnetic gap between the magnet 32 ​​and the stator 20 is determined by the distance between the outermost diameter portion 313a of the protruding portion 313 and the stator 20, it becomes necessary to set the distance between the anti-scattering member 34 and the stator 20 to be larger by the amount of the anti-scattering member 34 that is radially outward from the outermost diameter portion 313a of the protruding portion 313. This reduces the certainty of how large the above-mentioned distance should be set, making it difficult to manage the magnetic gap. In light of these points, in this embodiment, the outermost diameter portion 34g of the scattering prevention member 34 is positioned radially inward from the outermost diameter portion 313a of the protrusion 313. Therefore, the risk of the scattering prevention member 34 being damaged by being pressed against the outermost diameter portion 313a of the protrusion 313 can be avoided, and the magnetic gap can also be easily managed.

[0055] Furthermore, in this embodiment, the scattering prevention member 34 is made of a single ribbon-shaped sheet and has the following structure. That is, the scattering prevention member 34 comprises a spiral portion 34b that spirals around the rotor shaft 31 with an axial inclination, a one-end parallel portion 34c that spirals around at one end in the axial direction parallel to the circumferential direction, a other-end parallel portion 34e that spirals around at the other end in the axial direction parallel to the circumferential direction, and a folded spiral portion 34d that is folded back from one of the one-end parallel portion and the other-end parallel portion and spirals around towards the other. Here, in order to wrap the scattering prevention member 34 around the magnet 32 ​​using a simple manufacturing method, it is good to make a multi-layered structure by folding a single sheet back in the axial direction many times. However, when spiraling around and approaching one end in the axial direction, if it is folded back to the other end in the axial direction without having a one-end parallel portion 34c that spirals around parallel to the circumferential direction, it becomes difficult to cover the axial end of the magnet 32. The same applies to the other end in the axial direction. In consideration of this point, this embodiment has a parallel portion 34c on one end and a parallel portion 34e on the other end. This allows the magnet 32 ​​to be covered all the way to its axial end, even with a simple manufacturing method.

[0056] Furthermore, in this embodiment, the following points are the same regardless of the layer: namely, the axial length of the anti-scattering member, the winding pitch of the anti-scattering member, and the circumference length L1 of the parallel section at one end and the circumference length L2 of the parallel section at the other end are the same regardless of the layer. This suppresses variations in the thickness of the anti-scattering member 34 that wraps around the rotor shaft 31. As a result, the rotational balance of the rotor is improved.

[0057] Furthermore, when a single ribbon-shaped sheet is folded axially multiple times to create a multi-layer structure, the following problems may arise. Specifically, if the folding position of the anti-scattering member 34 is the same for each layer, the thickness will differ only in the folded portion, which may negatively affect the rotational balance. In light of this, in this embodiment, the positions of the parallel portion 34c on one end and the parallel portion 34e on the other end of the anti-scattering member 34 are evenly offset for each layer in the circumferential direction. This structure is achieved by adjusting the circumferential length L1 of the parallel portion 34c on one end and the circumferential length L2 of the parallel portion 34e on the other end to appropriate lengths. This makes it possible to evenly offset the folding position of the anti-scattering member 34 for each layer. As a result, the circumferential thickness becomes uniform, and it is possible to prevent the rotational balance from being disrupted.

[0058] Furthermore, in this embodiment, the anti-scattering member 34 is attached to the magnet 32 ​​by a method including the following first step S10 and second step S20. That is, in the first step S10, the anti-scattering member 34 is started to be wound around the magnet parallel to the circumferential direction with a tension less than a predetermined tension. The second step S20 is performed following the first step S10, and the anti-scattering member 34 is wound around the magnet spirally with a tension greater than a predetermined tension so as to be inclined in the axial direction along the circumferential direction. Here, in order to wind the anti-scattering member 34 around the outer circumferential surface 32a of the magnet 32 ​​while applying high tension, it is necessary to suppress slippage at the winding start. Possible methods to suppress slippage include clamping and fixing the winding start with a jig, or providing a hook on the rotor shaft or the like and fixing the winding start with the hook. However, the former method requires processing such as cutting off the excess protruding winding start end. Also, the latter method results in a more complex rotor shape and an increase in rotor weight.

[0059] In light of this, this embodiment includes a first step S10 in which winding begins by winding parallel to the circumferential direction. This increases the frictional force between the rotor shaft 31 or magnet 32 ​​and the anti-scattering member 34, suppressing slippage at the beginning of winding. Therefore, in the subsequent second step S20, the anti-scattering member 34 can be wound around the magnet 32 ​​with high tension without using jigs or hooks. In other words, a rotor 30 with the anti-scattering member 34 attached can be manufactured in a simple manner while suppressing weight increase.

[0060] Furthermore, in this embodiment, after the second step S20, there is a third step S40 in which the anti-scattering member 34 is wound around the rotor parallel to the circumferential direction. When winding the anti-scattering member 34 around the outer circumferential surface 32a of the magnet 32 ​​while applying high tension, it is necessary to fix the end of the winding, just like the beginning of the winding, to prevent the end of the winding from loosening. One way to suppress loosening is to provide a hook on the rotor shaft and fix the end of the winding to the hook. However, this method increases the number of steps and complicates the rotor shape, increasing the rotor weight. In consideration of this, this embodiment has a third step S40 in which the winding is wound around the rotor parallel to the circumferential direction. As a result, the end of the winding is less likely to loosen than if it were wound around in a spiral shape. Therefore, it is possible to suppress the decrease in tension at the end of the winding even without using a hook. In other words, a rotor 30 with an anti-scattering member 34 attached can be manufactured in a simple way while suppressing the increase in weight.

[0061] Furthermore, in this embodiment, the portion of the anti-scattering member 34 that is wrapped around in the third step S40 is wrapped over the portion that has already been wrapped. As a result, in addition to the pressing force toward the center of the circumference, the tackiness of the anti-scattering member 34 increases the adhesive effect at the end of the winding. Therefore, the end of the winding becomes less likely to loosen, and the effect of suppressing the decrease in tension at the end of the winding is promoted.

[0062] Furthermore, in this embodiment, after spiral rotation in the second step S20, a folding parallel step S31 and a folding spiral step S32 are performed. By repeating these steps, the anti-scattering member 34 becomes multi-layered. Moreover, multi-layering can be achieved with a single ribbon-shaped sheet. Therefore, the anti-scattering performance of the magnet can be improved in a simple manner.

[0063] Furthermore, in this embodiment, CFRP prepreg is used as the anti-scattering member 34. CFRP prepreg is lightweight, has high strength, and possesses high tackiness. Therefore, in addition to having high anti-scattering performance, it can fully exhibit the aforementioned slip suppression effect at the beginning of winding and loosening suppression effect at the end of winding.

[0064] (Second Embodiment) In the first embodiment described above, the rotor shaft 31 has a cylindrical base 311, a flange 312, and a protruding portion 313. In contrast, in the present embodiment shown in Figure 12, the protruding portion 313 is eliminated.

[0065] In this embodiment as well, the gap CL is filled with filler material 33. Therefore, as in the first embodiment, it is possible to prevent the scattering prevention member 34 from entering the gap CL. Thus, even if the scattering prevention member 34 is rotated under high tension to the axial end of the magnet 32, distortion and damage to the scattering prevention member 34 can be suppressed. In other words, since the scattering prevention member 34 can be rotated under high tension to the axial end of the magnet, high scattering prevention performance can be obtained. Furthermore, by rotating under high tension, high scattering prevention performance can be obtained with fewer rotations compared to when it is rotated under low tension. This also makes it possible to lighten the rotor. Moreover, since there is no protrusion 313, further weight reduction of the rotor is possible.

[0066] (Third Embodiment) In this embodiment shown in Figure 13, the protruding portion 313 is not tapered but has an arc shape. Therefore, in this embodiment, an arc surface 313c is formed instead of a tapered surface 313b. As a result, similar to the first embodiment, the arc surface 313c suppresses the axial spreading of the scattering prevention member 34.

[0067] In this embodiment as well, since the gap CL is filled with the filler material 33, it is possible to prevent the scattering prevention member 34 from entering the gap CL. Therefore, as in the first embodiment, even if the scattering prevention member 34 is rotated under high tension to the axial end of the magnet 32, distortion and damage to the scattering prevention member 34 can be suppressed. Furthermore, the arcuate surface 313c prevents the scattering prevention member 34 from being compressed radially and expanding axially over time. In other words, the same effects as in the first embodiment can be obtained.

[0068] (Fourth Embodiment) In this embodiment shown in Figure 14, the protrusion 313 is rectangular. Furthermore, the protrusion 313 is formed at a position spaced apart from the filler material 33. The outer surface 312a of the flange 312 lies on the same plane as the outer surface 32a of the magnet 32 ​​and the outer surface 33a of the filler material 33. Note that the shape of the protrusion 313 may be tapered or arc-shaped, rather than rectangular.

[0069] In this embodiment as well, since the gap CL is filled with the filler material 33, it is possible to prevent the scattering prevention member 34 from entering the gap CL. Therefore, similar to the first embodiment, even if the scattering prevention member 34 is rotated under high tension to the axial end of the magnet 32, distortion and damage to the scattering prevention member 34 can be suppressed.

[0070] (Other Embodiments) The disclosures of this specification are not limited to the exemplary embodiments. The disclosures encompass the exemplary embodiments and variations thereof by those skilled in the art. For example, the disclosures are not limited to the combinations of parts and elements shown in the embodiments, but can be implemented in various variations. The disclosures can be implemented in a variety of combinations. The disclosures may have additional parts that can be added to the embodiments. The disclosures encompass embodiments in which parts and elements have been omitted. The disclosures encompass substitutions or combinations of parts and elements between one embodiment and another. The scope of the disclosed technical field is not limited to the descriptions of the embodiments. The scope of the disclosed technical field is indicated by the claims and should be understood to include all modifications within the meaning and scope equivalent to the claims.

[0071] In each of the above embodiments, the outer surface 33a of the filler material 33 and the outer surface 32a of the magnet 32 ​​are on the same plane, but they do not have to be on the same plane. For example, the outer surface 33a of the filler material 33 may be radially outward from the outer surface 32a of the magnet 32. Also, the outer surface 32a of the magnet 32 ​​may be radially outward from the outer surface 33a of the filler material 33. Furthermore, the outer surface 33a of the filler material 33 may be inclined with respect to the axial direction of the rotor shaft 31.

[0072] Each of the above embodiments includes a folding parallel step S31, a folding spiral step S32, and a determination step S33. By repeating these steps, the scattering prevention member 34 is made to wrap around the outer circumferential surface 32a of the magnet 32 ​​in multiple layers. However, the folding parallel step S31, the folding spiral step S32, and the determination step S33 are not required. In other words, the scattering prevention member 34 that wraps around the outer circumferential surface 32a of the magnet 32 ​​may be a single layer.

[0073] The number of layers surrounding the anti-scattering member 34 may be one to eight, or ten or more. However, it is preferable that the number of layers surrounding the anti-scattering member 34 be odd. This ensures that if the starting parallel section 34a is on one end of the rotor shaft 31, the ending parallel section 34f will be on the other end. Therefore, the thickness of the anti-scattering member 34 can be made uniform on both ends of the rotor shaft 31, improving the rotational balance of the rotor 30.

[0074] In each of the above embodiments, the axial length of the scattering prevention member 34, the winding pitch of the scattering prevention member 34, and the circumference length L1 of the parallel portion 34c at one end and the circumference length L2 of the parallel portion 34e at the other end are the same regardless of the layer. However, these lengths may differ from layer to layer. For example, the axial length of the scattering prevention member 34 may be shorter only in the first circumference layer, or only in the last circumference layer, or only in the first and last circumference layers.

[0075] In each of the above embodiments, the positions of the one-end parallel section 34c and the other-end parallel section 34e are evenly offset for each layer in the circumferential direction, but they do not have to be evenly offset. Alternatively, the positions of the winding start parallel section 34a and the winding end parallel section 34f may be included in the one-end parallel section 34c and the other-end parallel section 34e, and all of these may be evenly offset for each layer in the circumferential direction. For example, if the number of circumferential layers is 7, position I shown in Figure 10 is the end position of the winding start parallel section 34a. Position VIII shown in Figure 10 is the end position of the winding end parallel section 34f. In this way, the winding start parallel section 34a, the winding end parallel section 34f, the one-end parallel section 34c, and the other-end parallel section 34e may be evenly offset for each layer in the circumferential direction. In this case, the circumference lengths of the starting parallel section 34a and the ending parallel section 34f may be the same as or different from the circumference length L1 of the parallel section 34c at one end and the circumference length L2 of the parallel section 34e at the other end.

[0076] In each of the above embodiments, there is a third step S40 in which the scattering prevention member 34 is wound around the circumference parallel to the circumferential direction, but this step is not required. That is, the scattering prevention member 34 may be wound while still in a spiral shape.

[0077] (Disclosure of Technical Ideas) This specification discloses several technical ideas as described in the following paragraphs. Some paragraphs may be written in a multiple dependent form, where subsequent paragraphs optionally refer to preceding paragraphs. Furthermore, some paragraphs may be written in a multiple dependent form, where they refer to other multiple dependent forms. These paragraphs written in multiple dependent forms define several technical ideas.

[0078] (Technical Concept 1) A rotor for a motor having a radial gap, comprising: a rotor shaft (31); a magnet (32) disposed on the outer circumferential surface of the rotor shaft; and a scattering prevention member (34) mounted so as to circle the rotor shaft along the outer circumferential surface (32a) of the magnet, thereby preventing the magnet from scattering radially outward from the rotor shaft, wherein the end face of the magnet located at the axial end of the rotor shaft is designated as the magnet end face (32b), the surface of the rotor shaft facing the magnet end face is designated as the rotor facing surface (312b), a filler (33) is filled in the gap (CL) between the magnet end face and the rotor facing surface, and the scattering prevention member is mounted on the magnet, covering a part of the rotor shaft together with the filler.

[0079] (Technical Concept 2) The rotor according to Technical Concept 1, wherein the scattering prevention member covers the entire outer surface of the magnet.

[0080] (Technical Idea 3) The rotor according to Technical Idea 1 or 2, wherein the outer surface (33a) of the filler and the outer surface of the magnet are on the same plane.

[0081] (Technical Idea 4) The rotor according to any one of Technical Ideas 1 to 3, wherein the anti-scattering member is arranged in multiple layers around the magnet.

[0082] (Technical idea 5) The rotor according to technical idea 4, wherein a protruding portion (313) is formed on the portion of the rotor shaft opposite to the rotor-facing surface to the filler material, protruding radially outward.

[0083] (Technical Idea 6) The rotor according to Technical Idea 5, wherein the protruding portion has a tapered or arc shape that gradually increases in diameter as it moves away from the filler.

[0084] (Technical Idea 7) The rotor according to Technical Idea 6, wherein the protrusion is formed at a position adjacent to the filler, and a part of the scattering prevention member is in contact with the protrusion.

[0085] (Technical Idea 8) The rotor according to technical idea 6 or 7, wherein the outermost diameter portion (34g) of the scattering prevention member is radially inward from the outermost diameter portion (313a) of the protruding portion.

[0086] (Technical Idea 9) The rotor according to any one of Technical Ideas 4 to 8, wherein the scattering prevention member is made of a single ribbon-shaped sheet, and the scattering prevention member has a spiral portion (34b) that spirals around along the circumferential direction of the rotor shaft with an axial inclination, a one-end parallel portion (34c) that spirals around at one end in the axial direction parallel to the circumferential direction, a other-end parallel portion (34e) that spirals around at the other end in the axial direction parallel to the circumferential direction, and a folded spiral portion (34d) that is folded back from one of the one-end parallel portion and the other-end parallel portion and spirals around toward the other.

[0087] (Technical idea 10) The rotor according to technical idea 9, wherein the axial length of the anti-scattering member, the winding pitch of the anti-scattering member, the circumference length (L1) of the parallel section on one end and the circumference length (L2) of the parallel section on the other end are the same regardless of the layer.

[0088] (Technical idea 11) The rotor according to technical idea 10, wherein the positions of the parallel portion on one end and the parallel portion on the other end are evenly offset layer by layer in the circumferential direction.

[0089] (Technical Idea 12) A method for manufacturing a rotor comprising: a rotor shaft (31); magnets (32) arranged on the outer circumferential surface of the rotor shaft; and a scattering prevention member (34) mounted so as to circumferentially wrap around the rotor shaft along the outer circumferential surface of the magnets, thereby preventing the magnets from scattering radially outward from the rotor shaft, the method comprising: a first step (S10) in which the scattering prevention member is started to be wound around the rotor with a tension less than a predetermined tension and parallel to the circumferential direction; and a second step (S20) performed following the first step in which the scattering prevention member is wound spirally around the rotor with a tension greater than or equal to the predetermined tension and inclined axially along the circumferential direction.

[0090] (Technical idea 13) A method for manufacturing a rotor according to technical idea 12, further comprising a third step (S40) in which the scattering prevention member is wound around the rotor parallel to the circumferential direction after the second step.

[0091] (Technical idea 14) The method for manufacturing a rotor according to technical idea 13, wherein the portion of the scattering prevention member that is rotated in the third step is rotated on top of the portion that has already been rotated.

[0092] (Technical Idea 15) A method for manufacturing a rotor according to any one of technical ideas 12 to 14, further comprising: a folding parallel step (S31) in which the rotor circulates in a spiral manner after the second step, and a folding spiral step (S32) in which the rotor circulates in a spiral manner by folding back from the portion that has circulated in parallel by the folding parallel step and overlapping with the portion of the scattering prevention member that has already circulated.

[0093] (Technical Idea 16) The method for manufacturing a rotor according to any one of Technical Ideas 12 to 15, wherein the anti-scattering member is a prepreg of carbon fiber reinforced plastic.

Claims

1. A rotor for a motor having a radial gap, comprising: a rotor shaft (31); a magnet (32) disposed on the outer circumferential surface of the rotor shaft; and a scattering prevention member (34) mounted so as to circle the rotor shaft along the outer circumferential surface (32a) of the magnet, thereby preventing the magnet from scattering radially outward from the rotor shaft, wherein the end face of the magnet located at the axial end of the rotor shaft is designated as the magnet end face (32b), the surface of the rotor shaft facing the magnet end face is designated as the rotor facing surface (312b), a filler (33) is filled in the gap (CL) between the magnet end face and the rotor facing surface, and the scattering prevention member is mounted on the magnet, covering a portion of the rotor shaft together with the filler.

2. The rotor according to claim 1, wherein the scattering prevention member covers the entire outer surface of the magnet.

3. The rotor according to claim 1 or 2, wherein the outer surface (33a) of the filler and the outer surface of the magnet are on the same plane.

4. The rotor according to claim 1, wherein the anti-scattering member is arranged in multiple layers around the magnet.

5. The rotor according to claim 4, wherein a projection (313) is formed on the portion of the rotor shaft opposite to the rotor-facing surface to the filler material, projecting radially outward.

6. The rotor according to claim 5, wherein the protruding portion has a tapered or arc-shaped form that gradually increases in diameter as it moves away from the filler.

7. The rotor according to claim 6, wherein the protrusion is formed adjacent to the filler, and a part of the anti-scattering member is in contact with the protrusion.

8. The rotor according to claim 6 or 7, wherein the outermost diameter portion (34g) of the scattering prevention member is radially inward from the outermost diameter portion (313a) of the protruding portion.

9. The rotor according to any one of claims 4 to 7, wherein the scattering prevention member is made of a single ribbon-shaped sheet, and the scattering prevention member has a spiral portion (34b) that spirals around along the circumferential direction of the rotor shaft with an axial inclination, a one-end parallel portion (34c) that spirals around at one end in the axial direction parallel to the circumferential direction, a other-end parallel portion (34e) that spirals around at the other end in the axial direction parallel to the circumferential direction, and a folded spiral portion (34d) that is folded back from one of the one-end parallel portion and the other-end parallel portion and spirals around towards the other.

10. The rotor according to claim 9, wherein the axial length of the anti-scattering member, the winding pitch of the anti-scattering member, the circumference length (L1) of the parallel portion at one end, and the circumference length (L2) of the parallel portion at the other end are the same regardless of the layer.

11. The rotor according to claim 10, wherein the positions of the parallel portion on one end and the parallel portion on the other end are evenly offset from layer to layer in the circumferential direction.

12. A method for manufacturing a rotor comprising: a rotor shaft (31); a magnet (32) disposed on the outer circumferential surface of the rotor shaft; and a scattering prevention member (34) mounted so as to circle the rotor shaft along the outer circumferential surface of the magnet, thereby preventing the magnet from scattering radially outward from the rotor shaft, the method comprising: a first step (S10) in which the scattering prevention member is started to be wound around the rotor shaft parallel to the circumferential direction with a tension less than a predetermined tension; and a second step (S20) performed following the first step in which the scattering prevention member is wound spirally around the rotor shaft with a tension greater than or equal to the predetermined tension, with an axial inclination.

13. The method for manufacturing a rotor according to claim 12, further comprising a third step (S40) after the second step, in which the anti-scattering member is wound around the rotor parallel to the circumferential direction.

14. The method for manufacturing a rotor according to claim 13, wherein the portion of the scattering prevention member that is rotated in the third step is rotated on top of the portion that has already been rotated.

15. A method for manufacturing a rotor according to any one of claims 12 to 14, further comprising: a folding parallel step (S31) in which the rotor circulates in a spiral manner after the second step, and a folding spiral step (S32) in which the rotor circulates in a spiral manner by folding back from the portion that has circulated in parallel by the folding parallel step and overlapping with the portion of the anti-scattering member that has already circulated.

16. The method for manufacturing a rotor according to any one of claims 12 to 14, wherein the anti-scattering member is a prepreg of carbon fiber reinforced plastic.

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