Motor and electric motorcycle equipped with it

Abstract

To provide a motor that can reduce the generation of vibration and noise. [Solution] The device comprises a fixed part and a rotating part 30. The fixed part includes a shaft extending along a central axis. The rotating part 30 rotates relative to the fixed part. The rotating part has a cylindrical rim 313, magnets 311, and a plurality of spacers 312. Multiple magnets 311 are arranged circumferentially on the inner circumferential surface of the rim 313. The spacers 312 are arranged between the magnets 311 in the circumferential direction. The radial outer ends of the spacers 312 are separated from the inner circumferential surface of the rim 313.

Description

Technical Field

[0001] The present invention relates to a motor and an electric bicycle equipped with the same.

Background Art

[0002] Conventional motors, for example, have a rotor (rotating part) including a cylindrical rotor outer cylinder, magnets, and a holder ring. The magnets are arranged in a plurality in the circumferential direction on the inner peripheral surface of the rotor outer cylinder. The holder ring holds the magnets and is formed in an annular shape that fits into the rotor outer cylinder. The holder ring is fitted inside the rotor outer cylinder and integrated. The holder ring has a plurality of partition pieces that project axially from the upper surface, and magnets are arranged between adjacent partition pieces (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in conventional motors, since the rotor outer cylinder and the holder ring are integrated and the dimensions between the partition pieces are determined, there is a possibility that a gap may occur between the magnet and the partition piece due to dimensional errors of the magnet. As a result, vibration and noise may occur during rotation of the rotor.

[0005] An object of the present invention is to provide a motor capable of reducing the generation of vibration and noise.

Means for Solving the Problems

[0006] An exemplary motor of the present invention comprises a stationary part and a rotating part. The stationary part includes a shaft extending along a central axis. The rotating part rotates relative to the stationary part. The rotating part has a cylindrical rim, magnets, and a plurality of spacers. The magnets are arranged circumferentially on the inner surface of the rim. The spacers are arranged between the magnets in the circumferential direction. The radial outer ends of the spacers are separated from the inner surface of the rim. [Effects of the Invention]

[0007] According to an exemplary version of the present invention, it is possible to provide a motor that can reduce the generation of vibration and noise. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram of an electric motorcycle according to an embodiment of the present invention. [Figure 2] Figure 2 is a cross-sectional view taken along line AA in Figure 1. [Figure 3] Figure 3 is a perspective view of the rotating part of a motor according to an embodiment of the present invention. [Figure 4] Figure 4 is an enlarged perspective view showing a portion of the rotating part of a motor according to an embodiment of the present invention. [Figure 5] Figure 5 is an enlarged view of a part of the rotating section of a motor according to an embodiment of the present invention, as seen from the inner side. [Figure 6] Figure 6 is a perspective view showing a portion of the rotating part of a motor according to an embodiment of the present invention, cut in a cross-section perpendicular to the axial direction. [Figure 7] Figure 7 is an enlarged view of a part of the rotating section of a modified motor according to an embodiment of the present invention, as seen from the inner side. [Modes for carrying out the invention]

[0009] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. In this specification, the direction parallel to the central axis of the motor will be referred to as the "axial direction," the direction perpendicular to the central axis of the motor will be referred to as the "radial direction," and the direction along the arc centered on the central axis of the motor will be referred to as the "circumferential direction." The central axis J of a motor mounted on a vehicle extends in the left-right direction of the vehicle.

[0010] Furthermore, in this application, "parallel directions" also includes substantially parallel directions. Furthermore, in this application, "orthogonal directions" also includes substantially orthogonal directions.

[0011] (1. Electric Motorcycle Configuration) An exemplary embodiment of the present invention, an electric motorcycle 1, will be described. Figure 1 is a schematic diagram of an electric motorcycle 1 according to an embodiment of the present invention.

[0012] The electric motorcycle 1 comprises a front wheel 2, a rear wheel 3, a body 4, handlebars 5, an ECU (electronic control unit) 6, a throttle 7, a battery 8, and a motor 10.

[0013] The front wheels 2 and rear wheels 3 are a pair of wheels. The front wheels 2 and rear wheels 3 are attached to the vehicle body 4. The handlebars 5 are attached to the front of the vehicle body 4.

[0014] The ECU6 is located inside the vehicle body 4. The ECU6 is a control unit. The throttle 7 is connected to the ECU6. The throttle 7 is a speed control mechanism.

[0015] Battery 8 is located inside the vehicle body 4. Battery 8 is connected to the ECU 6. Battery 8 is charged by the charger 9.

[0016] Motor 10 is mounted on the rear wheel 3. Motor 10 is connected to the ECU 6.

[0017] (2. Motor Configuration) Figure 2 is a cross-sectional view taken along line A-A in Figure 1. The motor 10 includes a fixed part 20, a rotating part 30, a cover 40, and a pair of bearing parts 50.

[0018] (2-1. Fixed Part) The fixed part 20 includes a shaft 21, a stator 22, and a holder 23. The shaft 21 extends along the central axis J. The shaft 21 is made of, for example, metal. The shaft 21 is in contact with the inner rings of the pair of bearing parts 50.

[0019] The stator 22 is annular. The center of the stator 22 coincides with the central axis J of the motor 10. The stator 22 has a stator core 221, an insulator (not shown), and a coil 223.

[0020] The stator core 221 is formed by laminating, for example, magnetic steel sheets in the axial direction. The stator core 221 has a core back 221a and teeth 221b. The core back 221a and the teeth 221b are integrally formed. The core back 221a surrounds the central axis J and is formed in an annular shape. The teeth 221b extend radially outward from the radially outer surface of the core back 221a and are arranged at equal intervals in the circumferential direction.

[0021] The insulator (not shown) covers at least a part of the stator core 221. The insulator is an insulating member that electrically insulates the stator core 221 and the coil 223. The insulator is attached to each tooth 221b.

[0022] The coil 223 excites the stator core 221. The coil 223 is formed by winding a conducting wire (not shown) around each tooth 221b via the insulator. A plurality of coils 223 are arranged in the circumferential direction.

[0023] The holder 23 is a disc-shaped pressed part, and the stator 22 is fixed to the outer circumference of the holder 23. The holder 23 has a holder through hole 23a that penetrates along the central axis J. For example, the shaft 21 is press-fitted into the holder through hole 23a, fixing the holder 23 and the shaft 21 together. In this way, the stator 22 is fixed to the shaft 21 via the holder 23.

[0024] (2-2. Rotating parts) The rotating part 30 rotates relative to the fixed part 20. The rotating part 30 rotates about the central axis J. The rotating part 30 has a cylindrical rim 313, a spacer 312, and a magnet 311. The spacer 312 will be described in detail later.

[0025] The rim 313 is a cylindrical casting. The rim 313 has a rim body portion 313a and a rim flange portion 313b. The rim body portion 313a is formed in a cylindrical shape, and a magnet 311 is arranged on its inner circumferential surface. The tire 3a is arranged on the outer circumferential surface of the rim body portion 313a. The rim flange portion 313b branches axially from the circumferential surface of the rim body portion 313a and extends radially outward. The rim flange portion 313b holds the tire 3a by clamping it from the axial direction.

[0026] Multiple magnets 311 are arranged radially outward of the stator 22 with gaps in between. Multiple magnets 311 are arranged on the inner circumferential surface of the rim 313 such that north poles and south poles are alternately arranged in the circumferential direction. The magnets 311 are made up of, for example, rectangular parallelepiped permanent magnets.

[0027] (3. Cover) The cover 40 is positioned on at least one side of the rim 313 in the axial direction. In this embodiment, the cover 40 is positioned on both sides of the rim 313 in the axial direction. The cover 40 is, for example, a wheel cover.

[0028] The cover 40 is disc-shaped and has a cylindrical portion 41 surrounding the central axis J. The interior of the cylindrical portion 41 penetrates the cover 40 axially and holds the bearing portion 50. The cover 40 is rotatably supported on the shaft 21 via the bearing portion 50.

[0029] (4. Rim and magnet mounting structure) Figure 3 is a perspective view of the rotating part 30, and Figure 4 is a perspective view showing an enlarged portion of the rotating part 30. Note that the adhesives 314a, 314b, 314c, and 314d are not shown in Figures 3 and 4. Figure 5 is an enlarged view of a portion of the inner circumferential surface of the rotating part 30 as seen from the inner side, and Figure 6 is a perspective view of an enlarged portion of the rotating part 30 cut in a cross section perpendicular to the axial direction.

[0030] The spacers 312 are positioned between the magnets 311 in the circumferential direction and are separate components from the rim 313. Each spacer 312 is also formed from a separate component. In this embodiment, the spacers 312 are made of resin. By arranging the magnets 311 in the circumferential direction via the spacers 312, the magnets 311 can be miniaturized in the circumferential direction, thereby reducing costs. Furthermore, regardless of the dimensional tolerance of the magnets 311, the distance between adjacent magnets 311 is uniformly determined to a predetermined width by the dimensions of the spacers 312. This suppresses the generation of vibration and noise when the rotating part 30 rotates.

[0031] In this embodiment, the spacer 312 has a first spacer 312a and a second spacer 312b. The first spacer 312a contacts the magnet 311 on one side in the axial direction above its axial center. The second spacer 312b contacts the magnet 311 on the side below its axial center in the axial direction. As a result, the magnet 311 is supported by the first spacer 312a and the second spacer 312b, preventing it from being positioned at an angle with respect to the axial direction.

[0032] An adhesive (first adhesive) 314a is placed between the first spacer 312a and the second spacer 312b. The adhesive 314a firmly fixes adjacent magnets 311 in the circumferential direction.

[0033] The radially outer end of the spacer 312 is positioned away from the inner circumferential surface of the rim 313 and radially inward from the radially outer surface of the magnet 311. Adhesive (second adhesive) 314b is placed between the inner circumferential surface of the rim 313 and the radially outer end of the spacer 312. The radially inner end of the spacer 312 is positioned radially outward from the radially inner surface of the magnet 311 (see Figure 6).

[0034] In this embodiment, the radial outer ends of the first spacer 312a and the second spacer 312b are positioned radially inward from the radial outer surface of the magnet 311. Adhesive (second adhesive) 314b is placed between the inner circumferential surface of the rim 313 and the radial outer surface of the first spacer 312a. Adhesive (second adhesive) 314b is also placed between the inner circumferential surface of the rim 313 and the radial outer end of the second spacer 312b. The adhesive 314b allows adjacent magnets 311 in the circumferential direction to be fixed more firmly. At this time, the first spacer 312a and the second spacer 312b prevent the adhesive 314b from protruding onto the radial inner surface of the magnet 311.

[0035] Furthermore, an adhesive (third adhesive) 314c is placed between the inner circumferential surface of the rim 313 and the radially outer surface of the magnet 311, and the magnet 311 and the rim 313 are fixed together via the adhesive 314c.

[0036] Furthermore, the adhesive 314d (fourth adhesive) spreads across one end face in the axial direction of adjacent magnets 311. This allows the adhesive 314b to more firmly fix adjacent magnets 311 in the circumferential direction to each other.

[0037] The method for attaching the magnets 311 to the rim 313 involves, for example, arranging the magnets 311 circumferentially on the inner surface of the rim 313, and then inserting the first spacer 312a and the second spacer 312b axially between the circumferential magnets 311. Finally, adhesive is injected between the inner surface of the rim 313 and the radially outer surface of the first spacer 312a. This causes the adhesive to flow into the gap between the first spacer 312a and the second spacer 312b, and into the gap between the inner surface of the rim 313 and the radially outer surface of the magnets 311. In addition, some of the adhesive spreads across the axial end faces of adjacent magnets 311.

[0038] Therefore, the adhesive (first adhesive) 314a, the adhesive (second adhesive) 314b, the adhesive (third adhesive) 314c, and the adhesive (fourth adhesive) 314d are integrally formed. That is, the adhesive (first adhesive) 314a and the adhesive (third adhesive) 314c are integrally formed. Also, the adhesive (second adhesive) 314b and the adhesive (third adhesive) 314c are integrally formed. As a result, adjacent magnets 311 in the circumferential direction and the magnets 311 and the rim 313 are more firmly fixed via the adhesives 314a, 314b, 314c, and 314d.

[0039] Figure 7 is an enlarged view of a portion of the inner circumferential surface of the rotating part 30 according to a modified example, as seen from the inner side. Multiple spacers 312 arranged in the circumferential direction are connected at one end in the axial direction via a connecting part 312c. The connecting part 312c is located on one side in the axial direction of the magnet and is formed in an annular shape with a gap between it and the inner circumferential surface of the rim 313. This improves the workability when inserting the spacers 312 between the circumferential directions of the magnet 311. In this embodiment, one end in the axial direction of multiple first spacers 312a is connected via the connecting part 312c. Alternatively, the other ends in the axial direction of multiple second spacers 312b may be connected via the connecting part 312c. Furthermore, the connecting part 312c does not have to be annular.

[0040] (5. Other) The embodiments described above are merely illustrative examples of the present invention. The configuration of the embodiments may be modified as appropriate without exceeding the technical spirit of the present invention. Furthermore, the embodiments may be combined to the extent possible. [Industrial applicability]

[0041] The motor of the present invention can be used, for example, in an electric motorcycle. [Explanation of symbols]

[0042] 1 Electric motorcycle 2 Front wheels 3 Rear wheels 3a tires 4 car bodies 5 handles 6 ECP 7 Throttle 8 batteries 9 charger 10 motors 20 Fixed part 21 Shaft 22 stata 23 Holder 23a Holder through hole 30 Rotating part 40 Cover 41 Cylinder part 50 Bearing section 221 Stator Core 221a Coreback 221b Teeth 223 Coil 311 Magnet 312 Spacer 312a First Spacer 312a Upper spacer 312b Second Spacer 312c connection part 313 Rim 313a Rim body 313b Rim flange section 314a, 314b, 314c, 314d Adhesives J center axis

Claims

1. A fixed part including a shaft extending along the central axis, It comprises a rotating part that rotates relative to the fixed part, The rotating part is, A cylindrical rim, On the inner circumferential surface of the rim, multiple magnets are arranged in the circumferential direction, A plurality of spacers, which are separate components from the rim and are arranged between the circumferential directions of the magnet, , has, Each of the aforementioned spacers is formed from a separate component, The radial outer end of the spacer is separated from the inner circumferential surface of the rim. The radial outer end of the spacer is positioned radially inward from the radial outer surface of the magnet. A second adhesive is placed between the inner circumferential surface of the rim and the radially outer end of the spacer. A third adhesive is placed between the inner circumferential surface of the rim and the radially outer surface of the magnet. A motor in which the second adhesive and the third adhesive are integrally formed.

2. The motor according to claim 1, wherein a plurality of spacers arranged in the circumferential direction are connected at one end in the axial direction via a connecting portion.

3. The motor according to claim 1 or claim 2, wherein the spacer comprises a plurality of first spacers that contact one side in the axial direction of the magnet's axial center, and a plurality of second spacers that contact the other side in the axial direction of the magnet's axial center.

4. A first adhesive is placed between the first spacer and the second spacer. The motor according to claim 3, wherein the first adhesive and the third adhesive are integrally formed.

5. The motor according to claim 1, wherein a fourth adhesive is arranged that extends across the axial end faces of adjacent magnets.

6. The motor according to any one of claims 1 to 5, wherein the spacer is made of resin.

7. An electric motorcycle having the motor described in any one of claims 1 to 6.

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