Yoke for bonded magnet motor

Abstract

To provide a yoke of a bond magnet motor capable of obtaining stable rotation performance without deteriorating centrifugal force resistance of a rotor rotating at a high rotation speed.SOLUTION: The yoke 10 of a bond magnet motor comprises a circumferentially split yoke 11 split in the circumferential direction, a radially split yoke 12 split in the radial direction and operable in the radial direction, and a core presser 13 facing a rotor core wherein the core presser 13 is fixed integrally to the radially split yoke 12.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a yoke for a bonded magnet motor. [Background technology]

[0002] Patent Document 1 describes a motor in which the main magnet is a sintered magnet and the auxiliary magnet is a bonded magnet, and the bonded magnet is oriented by applying a magnetic field to the workpiece beforehand and molding it, aligning the magnetization direction of the magnetic powder to create a strong magnet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-149059 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the molding pressure of the bonded magnet causes deformation of the bridges of the rotor core, generating tensile stress. As a result, the rotor's resistance to centrifugal force when rotating at high speeds is reduced. Furthermore, the presence of an orientation yoke around the rotor core makes it impossible to install a slide core. [Means for solving the problem]

[0005] In one embodiment, the yoke of the bonded magnet motor has a circumferentially divided yoke portion and a radially divided yoke portion, the radially divided yoke portion being movable in the radial direction, and the radially divided yoke portion and the core holding portion being attached integrally. [Effects of the Invention]

[0006] The yoke of the bonded magnet motor of the present disclosure provides stable rotational performance without reducing the centrifugal force resistance of the rotor rotating at high rotation speeds. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a cross-sectional view showing an example of a yoke of a bonded magnet motor according to a first embodiment. [Figure 2] FIG. 4 is a diagram showing an example of the sustained density of the yoke of the bonded magnet motor according to the first embodiment. [Figure 3] 2 is a perspective view showing an example of a radial split yoke portion 12 according to the first embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] Embodiment 1 Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of a yoke of a bonded magnet motor according to the first embodiment. FIG. 1 shows a quarter model of the yoke, and in reality, it is formed in a similar, approximately circular shape. In FIG. 1, yoke 10 includes circumferential divided yoke portion 11, radial divided yoke portion 12, core pressing portion 13, and coil 14.

[0009] Circumferentially divided yoke portion 11 is a yoke divided in the circumferential direction, which here refers to the circumferential direction of a circle drawn by the rotation of the bonded magnet motor.

[0010] Radial split yoke portion 12 is a yoke split in the radial direction. Radial split yoke portion 12 can move in the radial direction. Here, the circumferential direction refers to the radial direction of the circle drawn by the rotation of the bonded magnet motor.

[0011] The core retaining portion 13 is a member that faces the rotor core 20. The core retaining portion 13 is made of a non-magnetic material. For example, the core retaining portion 13 is preferably made of SUS304, aluminum, or copper. The core retaining portion 13 is attached integrally to the side of the radially-side split yoke portion 12 that contacts the rotor core 20. The rotor core 20 and the radially-side split yoke portion 12 are configured to press the rotor core. The rotor core 20 has a bonded magnet 21 inside.

[0012] The coil 14 is made of wound electric wire and generates a magnetic force when electricity is applied.

[0013] FIG. 2 is a diagram showing an example of the sustain density of the yoke of the bonded magnet motor according to the first embodiment. The division position of circumferential divided yoke portion 11 and radial divided yoke portion 12 is preferably in region C in FIG. 2, where the magnetic flux density is low. Also, core pressing portion 13 is preferably a notched spigot in region D in FIG. 2, where the magnetic flux density is low.

[0014] Fig. 3 is a perspective view showing an example of radial split yoke portion 12 according to embodiment 1. As shown in Fig. 3, by integrally attaching radial split yoke portion 12 and core pressing portion 13, the bridge portion of the rotor core does not expand due to molding pressure during the orientation molding process of the bonded magnet, and the allowable stress does not decrease.

[0015] In this way, the yoke of the bonded magnet motor of the first embodiment can provide stable rotational performance without reducing the centrifugal force resistance of the rotor rotating at high rotation speeds.

[0016] The present invention is not limited to the above-described embodiment, and modifications can be made as appropriate without departing from the spirit and scope of the present invention. For example, a magnetic ring may be inserted between the air gap between the yoke and the rotor core to allow magnetic flux to flow efficiently through the rotor core. Furthermore, by setting the air gap surface between the radial split yoke portion 12 and the rotor core 20 to be equal to or slightly larger than the air gap surface between the core retainer and the rotor core 20, the air gap can be made smaller, resulting in the effect of allowing magnetic flux to flow efficiently through the rotor core. [Explanation of symbols]

[0017] 10 York 11 Circumferentially divided yoke part 12 Radial side split yoke 13 Core holding part 13 14 coils 20 rotor core 21 Bonded Magnet

Claims

[Claim 1] a circumferentially divided yoke portion divided in the circumferential direction; a radially split yoke portion that is split in the radial direction and is movable in the radial direction; A core holding portion facing the rotor core is provided, The core pressing portion is a yoke of a bonded magnet motor that is integrally attached to the radially divided yoke portion.

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