JPS6223538B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to the structure of a stator for a mini motor.

[Background technology]

As shown in Figs. 1 and 2, the stator block of a conventional mini motor consists of two semi-cylindrical anisotropic magnets A and A that are brought into contact with each other to form a cylindrical magnetic column, and a cylinder with an opening on one side. The stator was formed by integrally molding synthetic resin on the bottom of the yoke. In this case, in order to fix the two magnets, it was necessary to fill the area around the magnets with synthetic resin.

However, in a stator constructed in this way, molding burrs are likely to occur on the outer peripheral surface of the magnet column due to variations in the finishing dimensional accuracy of magnets A and A, and magnets A and A are anisotropic. Therefore, there was a drawback that it was difficult to concentrate the magnetic flux on the tops of the outer peripheral surfaces of the magnets A and A, which were magnetized with different polarities, leading to a decrease in the efficiency of the motor.

[Purpose of the invention]

The present invention has been made to improve the above points, and its purpose is to create a stator for a mini motor that does not generate molding burrs on the outer peripheral surface of the magnet column and improves the efficiency of the motor. Our goal is to provide the following.

[Disclosure of the invention]

The stator of the mini motor of the present invention has two semi-cylindrical anisotropic magnets each having longitudinal grooves formed on the outer and inner circumferential surfaces of the holder, which is made of an elastic magnetic material and formed into a U-shape. The magnet column is assembled into a cylindrical shape by fitting opposing pieces into respective longitudinal grooves on the outer circumferential surface, and the outer circumferential surface of the magnet includes a magnet column whose outer circumferential surface tops are magnetized with different polarities, and an outer circumferential surface of the magnet column. It consists of a bottomed cylindrical yoke having an inner diameter larger than the diameter, and is integrated between one end surface of the magnet column and the bottom of the yoke, within the vertical groove of the inner circumferential surface of the magnet column, and on the other end surface of the magnet column. The above object is achieved by filling the magnet column with resin and coaxially integrating the magnet column with the yoke.

(Example) Examples of the present invention will be described below with reference to FIGS. 3 to 7.

In the figure, reference numeral 1 denotes two semi-cylindrical anisotropic magnets, one of which is magnetized with the top of its outer circumferential surface being N-pole, and the other with the top of its outer circumferential surface being magnetized with S-pole. magnet 1,1
A vertical groove 1b is formed in the center of the arc-shaped outer circumferential surface of
A vertical groove 1a is formed in the center of the inner peripheral surface. magnet 1,
1 are brought into contact with each other and held by a holder, which will be described later, to form a cylindrical magnet column. A through hole 4 is formed in the center thereof. One end of the through hole 4 has a slightly thicker diameter for fitting a bearing.

Reference numeral 3 denotes a holder formed by bending a band-like piece made of an elastic magnetic metal plate into a U-shape, and the opposing pieces 3b, 3b have elasticity on the inside. A through hole 3a is formed at the center of the bottom.

Fitting opposing pieces 3b, 3b of the holder 2 having approximately the same width as the longitudinal grooves 1b, 1b of the magnet column,
The elasticity of the facing piece 3b makes the connection between the magnets 1, 1 strong.

Reference numeral 2 denotes a cylindrical yoke with a bottom having an inner diameter larger than the outer diameter of the magnet column.

When assembling the stator of the mini motor of the present invention, nylon or the like is used between one end surface of the magnet column and the bottom of the yoke 2, within the vertical groove 1a of the inner peripheral surface of the magnet column, and on the other end surface of the magnet column. The magnetic column is coaxially integrated with the yoke 2 by filling it with a synthetic resin 5.

By doing so, the magnet column and the yoke 2 can be easily integrally molded, and burrs are not generated on the outer circumferential surface of the magnet column. This is because the magnets 1, 1 are held by the holder 3, which is formed by bending an elastic strip into a U-shape, and is used as a magnet column, so there is no need to cover the entire magnet column with the synthetic resin 5. It is.

Note that when integrally molding the magnet column and the yoke 2, it is not necessary to limit it to the embodiment shown in FIG. 3, and as shown in FIG. It may be integrally molded. Furthermore, as shown in FIG.
An insertion hole 2b, formed in the bottom surface of the yoke 2, with the tips of b, 3b slightly protruding from the end surface of the magnet column.
Insert into 2b and temporarily fix by caulking or press-fitting,
The synthetic resin 5 may be integrally molded on the bottom surface of the yoke 2. In this case, if stepped portions 3c, 3c as shown in FIG. 6 are formed near the tips of the opposing pieces 3b, 3b of the holder 3, a constant distance between the bottom surface of the yoke 2 and the end surface of the magnet column can be formed. It can be integrally molded with a gap in between and temporarily fixed.

Here, the flow of magnetic flux between the magnet column and the yoke 2 will be explained. Magnetic flux flows in the direction of the arrow shown in FIG. 7, forming a magnetic path. That is, one magnet 1
This is a magnetic path that passes through the yoke 2 via one opposing piece 3b of the holder 3, and reaches the other magnet 1 via the other opposing piece 3b. There is also a magnetic path from one magnet 1 through the opposing piece 3b and the bottom of the holder 3 to the other magnet 1, but in this case, the width of the peripheral part 3d of the through hole 3a at the bottom of the holder 3 is small; The magnetic resistance of this part increases, and there is little leakage of magnetic flux into this magnetic path. If the thickness of the holder 3, especially the bottom part 3d, is made thinner, the magnetic resistance will increase and the leakage magnetic flux will further decrease. In addition, by the function of the holder 3 as a magnetic metal plate, the magnetic flux can be concentrated on the top of the outer peripheral surface of the magnet column, and the efficiency of the motor can be improved.

〔Effect of the invention〕

As described above, the stator of the mini motor of the present invention has two semi-cylindrical anisotropic magnets each having longitudinal grooves formed on the outer and inner circumferential surfaces, which are formed in a U-shape using an elastic magnetic material. a magnet column, which is assembled into a cylindrical shape by fitting opposing pieces of the holder into respective vertical grooves on the outer circumferential surface, and in which the tops of the outer circumferential surfaces of the magnets are magnetized with mutually different polarities; It consists of a bottomed cylindrical yoke having an inner diameter larger than the outer diameter of the magnetic column,
Synthetic resin is filled between one end surface of the magnet column and the bottom of the yoke, in the vertical groove of the inner circumferential surface of the magnet column, and on the other end surface of the magnet column, so that the magnet column is coaxially integrated with the yoke. As a result, molding burrs do not occur on the outer circumferential surface of the magnet column, and a stator for a mini motor with improved motor efficiency can be provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional example, and FIG. 2 is a perspective view of the same. FIG. 3 is a sectional view showing one embodiment of the present invention, FIG. 4 is a sectional view showing another embodiment of the invention, and FIG. 5 is a sectional view showing another embodiment of the invention. FIG. 6 is a perspective view showing another embodiment of the present invention, and FIG. 7 is a sectional view illustrating the flow of magnetic flux according to the present invention. 1, 1...Magnet, 1a...Vertical groove, 1b...Vertical groove, 2...Yoke, 3...Holder, 3b, 3b...
...Opposing piece, 5...Synthetic resin.

Claims (1)

[Scope of Claims] 1. Opposing pieces of a holder in which two semi-cylindrical anisotropic magnets each having longitudinal grooves formed on the outer and inner circumferential surfaces are formed in a U-shape from an elastic magnetic material. a magnet column which is fitted into each longitudinal groove of the outer circumferential surface to form a cylindrical shape, the tops of the outer circumferential surfaces of the magnets being magnetized with different polarities; and It consists of a bottomed cylindrical yoke with a large inner diameter, and a synthetic resin is applied between one end surface of the magnet column and the bottom of the yoke, within the vertical groove of the inner peripheral surface of the magnet column, and on the other end surface of the magnet column. A stator for a mini motor, in which the magnetic column is filled and coaxially integrated with the yoke.