JPH0824417B2 - Permanent magnet magnetizing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a magnetizing device for permanent magnets in which N poles and S poles are alternately continuous, and particularly preferably used as an armature or a field magnet of an electric motor. The present invention relates to a permanent magnet magnetizing device having a non-magnetic flux region or a weak magnetic flux region.

(Prior Art) Conventionally, there is an electric motor as a typical example of a device having a permanent magnet in which N poles and S poles are alternately continuous. For example, in a DC motor, a cylindrical or disk-shaped permanent magnet is used as a field or armature. Is used. In this case, assuming that the number of poles is 4, the magnetic poles of the cylindrical and disc-shaped permanent magnets are distributed as shown in FIGS. 1 (a) and (b), and the magnetic field along the circumferential direction is The strength is as shown in FIG.

As is apparent from FIG. 2, it is difficult to improve the efficiency and characteristics of the motor because there is no magnetic flux region or weak magnetic flux region between adjacent magnetic poles.

FIG. 3 (a) is a diagram showing a typical example (for 4 poles) of a magnetizing device for producing the conventional permanent magnet shown in FIG. 1 (a),
FIG. 3 (b) is a diagram showing the operation. Fig. 3 (a)
In the figure, 20 is a magnetizing yoke, and 22 is a magnetizing coil, which are connected to the DC power source 26 via the switch 28. 24 is a magnetic material, for example, a cylindrical magnetized object. A coil 22 is wound around each of the protrusions 20a to 20d of the magnetizing yoke 20, and a DC current is momentarily applied to the coil 22, thereby moving the magnetized object 24 from the protrusion 20b as shown in FIG. 3 (b). Since the magnetic flux flows into the convex portion 20a through it, the S pole,
The N pole is generated and magnetized, and the distribution of the magnetic field strength resulting therefrom is as shown in FIG. 3 (c), and there is no non-magnetic flux or weak magnetic flux region.

Therefore, conventionally, a plurality of divided permanent magnets of each pole are fixed to each other through an adhesive or a fixing metal fitting in order to provide a weak magnetic flux region between the poles, as shown in FIGS. 4 to 6, for example. Known to.

These constitute the armature of the electric motor, and
The figure shows an armature to which a permanent magnet is fixed by a holding metal fitting,
The front cross-sectional view (a) shows a cross-section taken along the line AA in the side view (b), in which the permanent magnets 2 are fixed to the yoke 8 by pressing metal fittings 4 each including a screw. In the figure, 6 is a rotating shaft. In this case, the pressing metal part is in a weak magnetic flux region, but the work of fixing the permanent magnet with the pressing metal is troublesome, resulting in poor work efficiency and high cost. 5 and 6 show an armature in which a permanent magnet is fixed by a bind wire and a thin-walled stainless steel cylinder, respectively, and a side sectional view (b) shows a section taken along line AA of the front view (a). 5 and 6 show the permanent magnet 2 fixed to the yoke 8 with, for example, a stainless binding wire 10 and a thin stainless steel cylinder 12, and the stainless portion between the magnets is a weak magnet area, but the fixing work is troublesome. Therefore, the magnetic force of the permanent magnet decreases due to the binding wire and the cylinder, and the thickness increases the distance between the armature and the field, which further decreases the magnetic force, and the performance as an electric motor is reduced. Further, there is a problem that the adhesive portion is deteriorated due to aging, or that the fixed portion is loosened due to vibration and the permanent magnet piece comes off.

(Problems to be Solved by the Invention) An object of the present invention is to eliminate the above-mentioned drawbacks of conventional permanent magnets, in which S poles and N poles are alternately continuous through a non-magnetic flux region or a weak magnetic flux region and have good performance. (EN) It is possible to provide a magnetizing device for a permanent magnet, which is highly reliable and has an efficient assembling work.

(Means for Solving Problems) In order to achieve such an object, the present invention has a plurality of convex shapes and a magnetizing yoke, and a plurality of convex short-circuiting yokes,
The magnetizing yokes and the short-circuiting yokes are alternately arranged in close contact with each other in a row, and a yoke having a gap between the convex portions is wound in series on the convex portions of the plurality of magnetizing yokes. A rotating magnetizing coil, wherein the magnetizing coils are wound in opposite directions with respect to the protrusions of the adjacent magnetizing yokes, and one corresponding protrusion of each of the plurality of shorting yokes. And a plurality of short-circuit coils wound around the magnetizing coil, and the magnetizing device is configured such that both ends of the magnetizing coil are connected to a DC power supply. Therefore, with the magnetizing device having a simple structure in which the shorting yokes around which the short-circuit coils are wound are arranged alternately with the magnetizing yokes, the S pole and the N pole pass through the non-magnetic flux region or the weak magnetic flux region. It is possible to form alternating permanent magnets.

(Example) Hereinafter, an example of a magnetizing device for a permanent magnet according to the present invention will be described in detail with reference to the accompanying drawings.

7A and 7B show typical examples of permanent magnets produced by the permanent magnet magnetizing apparatus according to the present invention. FIG. 7A shows a cylindrical shape, and FIG. 7B shows a disk shape. , 40, N poles 30a, 40a, weak magnetic flux or non-magnetic flux region 30b,
40b, S poles 30c, 40c are alternately and continuously arranged, and are preferably permanent magnets for an armature or field of an electric motor, which is an example of four poles. The magnetic field strength distribution of such a permanent magnet is as shown in FIG. 8 and has a no magnetic flux or weak magnetic flux region 30b between the N pole and the S pole. As described above, the permanent magnet to which the present invention is applied obviously has no magnetic flux or a weak magnetic flux region, and when this permanent magnet is used as a field or armature of an electric motor, the efficiency and characteristics of the electric motor are An improved permanent magnet is provided, which is improved and which does not require assembling work because it is formed of one piece of magnetic material, has high work efficiency, and is strong against vibration during use and highly reliable.

Next, a magnetizing device according to the present invention for manufacturing such a permanent magnet will be described. 9 (a) is a top view of a typical example of a magnetizing device for producing the permanent magnet shown in FIG. 7 (a), and FIG. 9 (b) is a perspective view of the magnetizing device. In the figure, the same symbols as those in FIG. 3 have the same functions.

As can be seen from the figure, the magnetizing yoke 20 has convex portions 20a, 20b, 20c,
Shorting yokes (projections) 21a, 21b, 21c, 2 between 20d
1d, each convex portion 21a ~ 21d short-circuit coil 50a, 50b, 50
c and 50d are wound. The short-circuit coils 50a to 50d are short-circuit coils each having a plurality of turns (preferably one or two turns).

A method of magnetizing the magnetizing device shown in FIG. 9 will be described with reference to FIGS. 9 and 10. FIG. 10A is a partially enlarged view of the top view of the magnetizing device. First, when the switch 28 is momentarily closed and a current is passed through the magnetizing coil 22, the magnetic flux F is generated by the magnetizing yokes 20a, 20b.
And a part of the magnetic flux F ₁ passes through the short-circuiting yoke. Then, a current flows through the short-circuit coil 50b with a phase delay of about 90 ° with respect to the current in the coil 22 so as to generate a magnetic flux F ₂ that cancels the magnetic flux F ₁ . Therefore, in the short-circuiting yoke 21b, the magnetic flux F ₁
And F ₂ cancel each other out, resulting in a small amount of magnetic flux passing through the shorting yoke. Thus, (a), (b), (c) in FIG.
Weak magnetic flux (or no magnetic flux) as shown in each magnetic field strength distribution
The area 30b is provided in a portion facing the short-circuiting yokes 21a to 21d.

By the way, the maximum magnetic field strength Hm and its width W in the non-magnetic flux (weak magnetic flux) range are the resistance value of the short-circuit coil 50 and the short-circuiting yoke 21.
Width of b Y _W (Fig. 10 (b)), gear gap value Y _G between the top of the short-circuiting yoke and the top of the convex portion of the magnetizing yoke (Fig. 10 (b))
Etc.

That is, the smaller the resistance value of the short-circuit coil 5, the higher the density of the magnetic flux F ₂ generated, and thus the magnetic flux F ₁ is strongly canceled and the maximum magnetic field strength Hm (A / m) becomes weaker. That is, the smaller the number of turns of the coil 50 and the smaller the resistivity of the material of the coil 50, the higher the Hm.
Becomes smaller. Therefore, a one-turn coil (copper plate) preferably made of copper as shown in FIG. 11 is used as the short-circuit coil.

Further, the wider the width Y _W of the short-circuiting yoke, the larger the width W of the non-magnetic flux (weak magnetic flux) region.

Furthermore, the width W becomes narrower because the magnetic flux passing through the short-circuit yoke enough to Giyatsupu Y _G increases is diffused. Therefore preferably Giyatsupu Y _G is 1~2mm For permanent magnet such as small electric motors.

Therefore, in FIG. 8, (a) is a case where the resistance of the short-circuit coil is larger than that of (b), and (c) is (b).
Or width Y _W is larger than, or in the case Giyatsupu Y _G is small.

The permanent magnet to which the present invention is applied is not limited to the armature of the electric motor as in the above embodiment, and may be used as a field magnet.
As shown in FIG. 12, a linear magnet such as a permanent magnet for a linear motor may be used, and the magnetizing device in that case is as shown in the figure.

The permanent magnet to which the present invention is applied is not limited to an electric motor or a linear motor, and it is required that the S poles and the N poles are alternately continuous through a non-magnetic flux (or weak magnetic flux) region. It can be applied to all.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a conventional permanent magnet, FIG. 2 is a diagram showing a magnetic field strength distribution of the permanent magnet of FIG. 1, and FIG. 3 is a diagram showing a typical example of a conventional permanent magnet magnetizing device. 4 to 6 are diagrams for explaining a conventional permanent magnet fixing method having a weak magnetic flux region, FIG. 7 is a diagram of a typical example of a permanent magnet to which the present invention is applied, and FIG. 8 is a book. FIG. 9 is a diagram showing a magnetic field strength distribution of a permanent magnet to which the invention is applied, FIG. 9 is an example of a magnetizing device according to the present invention for producing a permanent magnet, and FIG. 10 is a principle of the magnetizing device of FIG. FIG. 11 is a diagram for explaining, FIG. 11 is a diagram showing an example of a short-circuit coil, and FIG. 12 is a diagram showing another example of a permanent magnet and a magnetizing device.

Claims (6)

[Claims] 1. A plurality of convex and magnetizing yokes, and a plurality of convex short-circuiting yokes, wherein the magnetizing yokes and the short-circuiting yokes are alternately and closely arranged in a line, and A yoke having a gap between the convex portions, and a magnetizing coil wound in series around the convex portions of the plurality of magnetizing yokes, wherein A magnetizing coil wound in mutually opposite directions, and a plurality of short-circuiting coils each wound around a corresponding one of the plurality of short-circuiting yokes are provided. A magnetizing device for a permanent magnet, characterized in that the magnetizing device is connected to. 2. The permanent magnet magnetizing device according to claim 1, wherein the height of the top of the magnetizing yoke is higher than the height of the top of the shorting yoke. 3. A magnetizing device for a permanent magnet according to claim 1, wherein the maximum magnetic field strength of the non-magnetic flux region or the weak magnetic flux region of the magnetized body is determined by the resistance value of the short-circuit coil. 4. The magnetizing device for a permanent magnet according to claim 1, wherein the width of the non-magnetic flux region or the weak magnetic flux region of the magnetized body is determined by the width of the short-circuiting yoke. 5. The magnetizing device for a permanent magnet according to claim 1, wherein the short-circuit coil is a one-turn coil. 6. The width of the non-magnetic flux region or the weak magnetic flux region of the magnetized body is determined by the width between the top of the magnetizing yoke and the top of the short-circuiting yoke. Magnetizing device for permanent magnets.