JPS61116620A - Magnetic circuit device - Google Patents

Abstract

PURPOSE:To miniaturize the device as a whole, by achieving a radial orientation employing a resin magnet as the permanent magnet to arrange a ring-shaped yokes both inside and outside the magnet. CONSTITUTION:An internal yoke 13 and an external yoke 14 are fitted into the inner and outer surface of the permanent magnet 12 comprising a ring- shaped resin magnet. The magnetic pole of the permanent magnet 12 provides a radial orientation with the inner surface thereof serving as the S pole and the outer surface thereof the N pole. Then, rotors 5 arranged at a fixed space are so constructed to have a cylindrical or columnal permanent magnet 8 fastened in a cylindrical rotor armor body 7 and the outer surface of the armor body 7 is colored differently corresponding to both sides of line connecting S and N poles of the permanent magnet 8. The vertical movement of the permanent magnet 12, the rotor armor body 7 turns to show the different color thereof 7.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic circuit device which is attached to a float stored in a tank or the like and floated therein.

(Prior Art) First, in order to make it easier to understand, a brief explanation of the first drawing of a magnetic liquid level gauge in which such a magnetic circuit is used as a raw material will be given. A tyt indicator B2 is attached along the outside of a stand column l that is connected and vertically attached, and a float 4 with a magnetic circuit 3 attached thereto is inserted into the column l in a floating state. , a horizontal shaft 6 with a large number of rotors 5 arranged at regular intervals.
The rotor 5 has a structure in which a cylindrical or cylindrical permanent magnet 8 is fixed inside a cylindrical rotor exterior body 7, and the outer surface of the exterior body 7 has a Both sides of the line connecting the S and N poles of the permanent magnet 8 are colored in different colors. Therefore, the rotor 5 is
The floats 4 are magnetically attracted and restrained, and remain stably stationary even when shaken, etc., and move up and down as the liquid level changes.
When the magnetic circuit 3 approaches, it is attracted by the magnetic force and rotates half a rotation, and the different colors of the exterior body 7 are displayed.

By the way, the magnetic circuit 3 shown in FIG. 2 is most commonly used.

In the same figure, 3a and 3b are a pair of permanent magnets, 3C is a yoke, 9 is a non-magnetic case, 1O is a flow of magnetic flux, and 11 is a display board.This magnetic circuit 3 includes two permanent magnets 3a and 3b. Since the permanent magnets 3a and 3b are arranged with the same polarity facing each other with the yoke 3c in between, the magnetic flux flow 10 generated in the permanent magnets 3a and 3b passes through the yoke 3c with almost no leakage and is focused at a relatively far distance. This is the best one available at the moment.

(Problem to be solved by the invention) However, the conventional magnetic circuit 3 described above has 31 parts.
1, and the pair of permanent magnets 3a and 3b are bonded to the yoke 3c with the same polarity facing each other, which requires extremely complicated work, which is a factor in high costs. In addition, since the two magnets 3a and 3b are polymerized, the weight becomes large, and when attached to the float 4 for the liquid level gauge described above, there is a disadvantage that the entire device becomes large.

(Means for Solving the Problems) This invention was made in view of the above-mentioned conventional problems, and includes a ring-shaped internal yoke and an external yoke on the inner and outer peripheral surfaces of a ring-shaped permanent magnet, respectively. The permanent magnet is made of a plastic magnet containing rare earth magnetic powder at a high filling rate and molded using a resin as a binder, and the magnetic poles have different radial orientations on the inner surface and the outer surface. The gist of the present invention is a magnetic circuit device having a configuration in which the outer peripheral surface side is thinner than the inner peripheral surface side.

(Function) With the above configuration, radial orientation is achieved by using plastic magnets as permanent magnets, and ring-shaped yokes are fitted on both the inner and outer sides of this magnet, so that one small magnet This enables extremely strong magnetic force to be obtained, allowing the device to be made smaller when applied to a magnetic liquid level needle, for example, and because the outer periphery of the ring-shaped permanent magnet is thinner than the inner periphery, the magnetic flux can be reduced. It has sharp focusing and can reach long distances.

(Embodiment) Hereinafter, a preferred embodiment of the magnetic circuit device of the present invention will be described in detail with reference to the drawings.

3 to 5, 12 is a permanent magnet made of a ring-shaped plastic magnet, and 13 and 14 indicate an inner yoke and an outer yoke fitted to the inner and outer circumferential surfaces of the permanent magnet 12, respectively. The permanent magnet 12 contains rare earth magnetic powder at a high filling rate and is bonded and molded with plastic, and the magnetic poles are radially oriented with the inner periphery being the S pole and the outer periphery being the N pole, as shown in FIG. Further, as shown in FIG. 5, the outer peripheral edges of both surfaces are inclined so that the outer peripheral part is thinner than the inner peripheral part. Therefore, the external yoke 14 has a width that is approximately the same as the outer peripheral end surface of the permanent magnet 12, and is narrower than the internal yoke 13, which has approximately the same width as the inner peripheral end surface of the permanent magnet 12.

The operation of the magnetic circuit device having the above structure will be explained based on FIG. 6, which shows the case where this device is applied to a magnetic liquid level gauge. Since we created a plastic magnet that can be formed into any shape, which was impossible to manufacture using the binding method, we made the magnetic poles radially anisotropic. Therefore, the outer peripheral end surface portion of the permanent magnet 12 is entirely N8i in the vertical direction, and the second
FI! As is clear from J, this kind of conventional permanent magnet 3
In a and 3b, there are N and S poles on the top and bottom of the circumferential surface, so a single permanent magnet 12 is sufficient, unlike the case where the N poles face each other and their magnetic force is focused by passing through the yoke 3c. A magnetic force is obtained, and this magnetic force is transferred to the yoke 13.1.
4, the magnetic flux is radiated without leakage, and the outer circumferential portion of the permanent magnet 12 is made thinner than the inner circumferential portion and is sloped so as to be sharply pointed, so that the magnetic flux flow 15 becomes sharp as shown in the figure. They are not distributed over a wide range, and only approximately the corresponding rotor 5 can be caused to perform a reversal action. In this way, this magnetic circuit device is lightweight and can accurately detect position.

It goes without saying that the magnetic circuit device of the present invention can be used not only for the above-mentioned magnetic liquid level needle, but also for any display device, position detection device, etc. that is configured to act on a magnetic display object.

(Operation and Effect of the Invention) As described above, according to the magnetic circuit device of the present invention, it is possible to obtain almost the same magnetic force with a single permanent magnet as that of a conventional pair of magnets with the same polarity facing each other. It is extremely lightweight, and devices that can be used with it, such as magnetic liquid level needles, can be made much smaller and lighter, and they can be manufactured with ordinary plastic molding methods, and the yoke 1
3.14 can be attached integrally using inserts, outserts, etc., so it has the advantage of being able to significantly reduce costs compared to conventional products of this type. Also, since the ring-shaped outer circumference is tapered to the inner circumference,
This has the effect of sharpening the slope of the magnetic flux flow and focusing it over a long distance. Furthermore, since ring-shaped corks are fitted to the inner and outer circumferential surfaces of the permanent magnet, this cork reinforces the permanent magnet, resulting in various practical effects such as making it robust against the weight of eggs. It is something that plays.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of a part of a magnetic liquid level needle to which this invention is mainly applied, Fig. 2 is a longitudinal sectional view of a conventional magnetic circuit applied to a magnetic liquid level gauge, and Fig. 3 5 to 5 show an embodiment of the magnetic circuit device of the present invention, FIG. 3 is a perspective view, FIG. 4 is a plan view, FIG. 5 is a partial vertical sectional view, and FIG. ) is a vertical cross-sectional view showing a state in which the liquid level needle is used. 12,000 permanent magnets, 13 - internal yoke, 111 - external yoke.

Claims (1)

[Claims] (1) A ring-shaped internal yoke and an external yoke are fitted to the inner and outer peripheral surfaces of a ring-shaped permanent magnet, respectively, and the permanent magnet contains rare earth magnetic powder at a high filling rate and is made of resin. A magnet made of a plastic magnet molded as a binder, and characterized in that the magnetic poles have different radial orientations on the inner and outer sides, and the outer circumferential side is thinner than the inner circumferential side. circuit device.