Rotor magnetization jig

Abstract

This technology provides a way to reduce noise and vibration during the magnetization of the rotor. [Solution] The rotor magnetization jig comprises a first jig that supports one axial end face of the rotor core, to which a shaft is assembled, from above, and a second jig that supports the other axial end face of the rotor core from below. The second jig includes a support portion having an outer peripheral surface facing the inner wall of the magnetization yoke, and the support portion includes one or more concave portions that are recessed from the outer peripheral surface toward the shaft so as to move away from the inner wall along the circumferential direction of the outer peripheral surface.

Description

Technical Field

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[0001] The technology disclosed in this specification relates to a magnetization jig for a rotor.

Background Art

[0002] The rotor needs to be magnetized at the end of its assembly process. Magnetization of the rotor is performed by applying an external magnetic field to the magnets enclosed in the rotor core to impart magnetic force. To generate a magnetic field, the rotor is placed inside a magnetization yoke wound with a coil, and a high voltage of several thousand volts is applied to the magnetization yoke in an instant. A Lorentz force is generated in the rotor and the jig by the magnetic field generated inside the magnetization yoke.

[0003] A device for holding the lower end of the rotor with a jig for rotor holding and magnetizing it during magnetization has been disclosed (Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] It is known that sound and vibration are generated due to the generation of Lorentz force during magnetization. Depending on the size of the rotor and the increase in magnetization voltage, even greater sound and vibration may occur during magnetization. The inventors of the present invention focused on the fact that the Lorentz force due to the magnetic field is generated in the rotor and the jig and finally generated as the resultant force thereof. Furthermore, regarding the sound and vibration generated during magnetization, the inventors focused on the fact that the balance of the Lorentz force applied to the jig used is disrupted and the resultant force becomes large.

[0006] This specification provides a technology for suppressing the sound and vibration generated during magnetization.

Means for Solving the Problems

[0007] The technology disclosed herein is embodied in a jig used for magnetizing a rotor. The jig comprises a first jig that supports one axial end face of the rotor core, on which a shaft is assembled, from above, and a second jig that supports the other axial end face of the rotor core from below. The second jig includes a support portion having an outer circumferential surface facing the inner wall of a magnetization yoke, and the support portion includes one or more concave portions that recess from the outer circumferential surface toward the shaft so as to move away from the inner wall along the circumferential direction of the outer circumferential surface.

[0008] With this magnetization jig, the second jig, by having the concave portion, can reduce the resultant force of the Lorentz force generated in the rotor and the magnetization jig. As a result, noise and vibration during magnetization are suppressed. [Brief explanation of the drawing]

[0009] [Figure 1] This is a cross-sectional view showing a magnetization yoke for magnetizing a rotor and a rotor installed within the magnetization yoke. [Figure 2] Figure 1 illustrates the Lorentz force generated near the second jig within the dotted rectangle II. [Figure 3] This figure shows various forms (a) to (c) of the concave portion in the second jig. [Modes for carrying out the invention]

[0010] Hereinafter, embodiments of the rotor magnetization jig set of this disclosure will be described with reference to the drawings as appropriate. In this specification, when "axial direction" is used, it refers to the axial direction of the rotor shaft.

[0011] The magnetization tools disclosed herein are used, for example, to magnetize the rotors of vehicle-mounted motors that drive the wheels of electric vehicles such as HEVs and BEVs.

[0012] Figure 1 shows a magnetization yoke 2, a rotor 20 installed within the magnetization yoke 2, and magnetization jigs 30 and 40 (hereinafter referred to as the first jig 30 and the second jig 40, respectively). The magnetization yoke 2 has a cylindrical shape that allows the rotor core 22 of the rotor 20 to be magnetized. The magnetization yoke 2 is made of a metal such as iron. The magnetization yoke 2 is equipped with coils, etc. (not shown), corresponding to the magnetization pattern.

[0013] The rotor 20 comprises a rotor core 22 and a rotor shaft 24 fixed to the center of the rotor core 22. The rotor core 22 is made of, for example, laminated steel plates, and permanent magnets (not shown) are embedded and sealed within it in a predetermined pattern along the axial direction.

[0014] The rotor shaft 24 has a cylindrical shape, for example, with a hollow portion 24a in the axial direction, and protrudes from one end face (in this case, the upper end face) 22a and the other end face 22b of the rotor core 22, respectively. The rotor shaft 24 has a separate holding member 25 that abuts against and holds the end face 22a of the rotor core 22 from one side. It also has a holding portion 26 that abuts against the end face 22b of the rotor core 22 to hold the rotor shaft 24.

[0015] The rotor 20 is held within the magnetization yoke 2 by a first jig 30 and a second jig 40. The first jig 30 is designed to hold the end face 22a of the rotor core 22 from above. The first jig 30 has a hole 32 that accommodates the rotor core 22 and the upper part of the rotor shaft 24. In the first jig 30, a cylindrical support portion 34 around the hole 32 abuts against the end face 22a of the rotor core 22 to support the rotor core 22. The upper end of the first jig 30 is fixed to the equipment by inserting a support shaft 38 for fixing the first jig 30 and the rotor 20 in a predetermined position.

[0016] The second jig 40 is designed to hold the end face 22b of the rotor core 22 from below. The second jig 40 is formed in a substantially cylindrical shape. The second jig 40 has a hole 42 in its central portion that can accommodate the holding portion 26 of the rotor shaft 24 and the portion of the rotor shaft 24 that protrudes below the holding portion 36. Near the end face 22b, the hole 42 has a large-diameter opening 42a that accommodates the holding portion 26 and also holds a rotation-restricting member 28 for preventing the rotation of the rotor shaft 24, and a smaller-diameter opening 42b below it.

[0017] The cylindrical support portion 44 around the hole 42 of the second jig 40 supports the lower part of the rotor core 22. The support portion 44 has a ring-shaped top surface 46 that abuts against the outer circumference portion of the end face 22a of the rotor core 22. The support portion 44 is formed with a thinner wall thickness around the large diameter opening 42a near the end face 22b than other parts, and a thicker wall thickness around the small diameter opening 42b than around the large diameter opening 42a. The other side of the second jig 40 is fixed to a jig 60 which is fixed to the equipment.

[0018] Here, a concave portion 50 is formed on the outer circumferential surface 48 of the support portion 44 of the second jig 40, along its circumferential direction. The concave portion 50 is formed in a concave shape that faces the inner wall 4 of the magnetization yoke 2, away from the surface of the inner wall 4, and recesses toward the rotor shaft 24 from the outer circumferential surface 48. In Figure 1, the concave portion 50 is formed on the support portion 44, maintaining the same height and extending over the entire circumference of the outer circumferential surface 48.

[0019] The shape of the concave portion 50 is set so as to reduce the combined force of the Lorentz forces generated during magnetization in the rotor 20, the first jig 30, the second jig 40, and the like. FIG. 2 illustrates the second jig 40 and shows the downward Lorentz force F generated during magnetization. For example, an upward Lorentz force is generated in the first jig 30. According to the inventors, if the combined force of the generated Lorentz forces is large, the object inside the magnetization yoke 2 tries to move and large noises and vibrations are generated. In setting the shape of the concave portion 50, based on the finding by the inventors that noise and vibration can be suppressed by balancing so as to reduce the combined force of the Lorentz forces generated during magnetization in the rotor 20, the first jig 30, the second jig 40, and the like.

[0020] For example, based on the shape of the rotor 20, the shapes of the first jig 30 and the second jig 40, and the magnetization conditions, the Lorentz forces generated are analyzed for the shape of the concave portion 50. For example, the combined force such as the combined force in the vertical direction is calculated, and the shape of the concave portion 50 in the second jig 40 is selected so that such a combined force becomes small. Further, the shape of the concave portion 50 may be determined in consideration of its manufacturing efficiency and the like.

[0021] For example, adjustment of the facing area of the support portion 44 facing the inner wall 4 of the magnetization yoke 2 may be effective for reducing the combined force of the Lorentz forces. For this purpose, for example, the opening width and the number of the concave portions 50 can be appropriately set. Also, adjustment of the amount of formation of the air layer in the concave portion 50 may be effective for reducing the combined force of the Lorentz forces. For this purpose, for example, by making the shape of the concave portion 50 have a curved bottom, it is possible to easily form an air layer and make it difficult for the magnetic field to pass through.

[0022] [[ID={ "12": "Furthermore, considering adjustments such as the strength of the jig 40 and the cutting amount, the shape of the concave portion 50 can be made into a square cross-sectional shape, a substantially triangular cross-sectional shape, etc., or the opening width and the number can be appropriately set.

[0023] The concave portions 50 illustrated in FIG. 1 are two concave portions 50 having the same cross-sectional rectangular shape and are parallel to each other at a certain interval. For example, the concave portion 50a shown in FIG. 3(a) has a plurality of concave portions 50a installed such that the opening width along the gravitational direction of the concave portion 50a is narrowed while maintaining the facing area facing the inner wall 4 to be substantially the same as that of the concave portion 50 and facing the inner wall 4 of the magnetization yoke 2 more uniformly (linearly). By doing so, the strength of the second jig 40 is ensured.

[0024] Further, the concave portion 50b shown in FIG. 3(b) has a concave shape with a substantially triangular cross-section, thereby reducing the cutting amount while ensuring an opposing area equal to or larger than that of the concave portion 50, and ensuring the jig strength.

[0025] Further, the concave portion 50c shown in FIG. 3(c) has a concave shape with a curved bottom surface while reducing the opposing area, thereby increasing an air layer where it is difficult for a magnetic field to enter.

[0026] As described above, according to the second jig of the magnetization jig disclosed in the present specification, by reducing the resultant force of the Lorentz forces during magnetization, noise and vibration during magnetization can be reduced.

Explanation of Reference Numerals

[0027] 2 Magnetization yoke, 4 Inner wall, 20 Rotor, 22 Rotor core, 22a, 22b End faces, 24 Rotor shaft, 25 Holding member, 26 Holding portion, 28 Rotation restraining member, 30 First jig, 32 Hole portion, 34 Support portion, 40 Second jig, 42 Hole portion, 44 Support portion, 46 Top surface, 48 Outer peripheral surface, 50, 50a, 50b, 50c Concave portion

Claims

[Claim 1] A magnetization jig for a rotor, A first jig supports one axial end face of the rotor core, to which a shaft is assembled, from above, A second jig supports the other axial end face of the rotor core from below, Equipped with, The second jig comprises a support portion having an outer peripheral surface facing the inner wall of a magnetizing yoke, and the support portion comprises one or more concave portions that recess toward the shaft from the outer peripheral surface so as to move away from the inner wall along the circumferential direction of the outer peripheral surface.

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