JPH01238103A - Magnet device and manufacture thereof - Google Patents

Abstract

PURPOSE:To form a sharp neutral zone with excellent positional accuracy by fixing units, in which a plurality of permanent magnets are juxtaposed, under the state in which the end faces of the corresponding permanent magnets in each unit are faced oppositely and fast stuck, pairing the corresponding permanent magnets and magnetizing the pairs of the oppositely faced permanent magnets so as to have bipolar on the same planes. CONSTITUTION:A first unit 34 disposed in an array to a first non-magnetic support member 32 under the state, in which a plurality of tabular permanent magnets 30 are erected at regular intervals, and a second unit 40 juxtaposed to a second non-magnetic support member 38 under the state in which tabular permanent magnets 36 in the same number as mentioned above are erected at the same intervals as mentioned above are provided. The corresponding permanent magnets 30, 36 in both units 34, 40 are paired, and the nose faces of the permanent magnets 30, 36 are fast stuck and fastened under the state in which the nose faces are mutually faced oppositely, and the pairs of the fast stuck and opposed permanent magnets 30, 36 are magnetized so as to have bipolar on the same planes. Consequently, the adhesive surfaces of the permanent magnets 30 for the first unit 34 and the permanent magnets 36 for the second unit 40 accurately function as neutral zones, and are formed in an extremely sharp surface. The positional precision of the neutral zones can be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnet device in which a plurality of permanent magnets are arranged side by side and a method for manufacturing the same, and more specifically, to a magnet device in which a plurality of permanent magnets are arranged vertically at intervals. The present invention relates to a magnet device in which two units made up of the following permanent magnets are brought into close contact with each other so that their respective permanent magnets face each other and have two polarities on the same plane, and a method for manufacturing the same.

The present invention is a magnet device suitable for applying a driving magnetic field to a driving element including a dot pin and a moving coil in, for example, a moving coil type impact dot printer.

[Prior Art] A moving coil type impact dot printer uses a dolmen device in which a plurality of permanent magnets are set up at regular intervals.
It is known that a driving element including a flat movable coil, a recovery spring, a dot pin, etc. is arranged in the gap between adjacent permanent magnets to enable high-speed printing.

As shown in FIG. 2, for example, a conventional magnet device of this type includes a plurality of bipolar magnetized plate-shaped permanent magnets IO arranged vertically at regular intervals on a non-magnetic support member 12, and an adhesive 14
There is something that is stuck. In applications such as those described above, each permanent magnet 10 must be fixed with a high degree of accuracy, typically on the order of 0.02 degrees.

The specific manufacturing procedure is as follows.

(2) Apply epoxy adhesive to the adhesive surface of the non-magnetic support member 12 at a constant ffi.

■ Attach the adhesive jig 16 for positioning the permanent magnet IO.

(2) Insert the permanent magnet IO, which has been fitted with two poles in advance, into the gear of the adhesive jig 16.

(2) The adhesive 14 is cured by heating (for example, at 160° C. for 51 hours).

■ Remove the adhesive jig 16.

Using the magnet device 18 thus obtained, a moving coil impact dot printer is assembled by disposing drive elements 20 as shown in FIG. 3 in the gaps between adjacent permanent magnets 10. Here, the drive element 20 consists of a flat movable coil 22, a coil base 24 that holds it, a return spring 26 that swingably holds the coil base 24, and a dot pin 28 attached to the tip of the coil base 24. Become.

When a drive current is supplied to the flat moving coil 22, a driving magnetic field is applied by the magnet device, so the flat moving coil 22 descends against the elastic force of the return spring 26 according to Fleming's left-hand rule and reaches the surface of the paper. Print by applying a shock,
When the supply of drive current is stopped, the return spring 26 returns it to its original position.

[Problems to be Solved by the Invention] In the magnet device having the conventional structure as described above, due to its structure, there are restrictions on the wearing procedure, and there are the following problems.

+a+ It is important to perform bipolar magnetization so that the neutral zone is sharp and formed with good positional accuracy, but for this purpose, the permanent magnets must be magnetized one by one. For this reason, workability is poor, and the magnetization yield is also poor.
Also, the magnetizing yoke needs to be highly accurate, which makes it expensive.

(bl) Since the fixed permanent magnets are glued to the non-magnetic support member, they are strongly attracted to the adjacent permanent magnets. Therefore, it is very difficult to handle.Also, since the permanent magnets are positioned using an adhesive jig, etc. There is a risk that the permanent magnet may be chipped when inserting the permanent magnet into the jig or removing the jig after adhesion.

If an adhesive jig is not used, the magnetic force of other permanent magnets may cause the permanent magnets to be glued together, which not only reduces assembly accuracy but also reduces adhesive strength.

[Since the permanent magnets are assembled after magnetizing 11 Cs at a time, the permanent magnets are always in a low permeance state.

Therefore, permanent magnets with large coercive force (bHc) must be used in all cases.

(di) It is necessary to degrease and clean the permanent magnet after adhering it to a non-magnetic support member, but since it is already magnetized, automatic cleaning is not possible and it is necessary to clean it individually, which is poor work efficiency. .

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, to provide a magnet device that can form a sharp neutral zone with high precision, has good magnetic properties, and is very easy to manufacture, and a method for manufacturing the same. It's about doing.

(Means for Solving the Problems) The present invention, which can achieve the above objects, includes a first unit in which a plurality of permanent magnets are erected on a first non-magnetic support member at predetermined intervals; and a second unit in which the same number of permanent magnets are erected on a second non-magnetic support member at the same intervals as above, and the corresponding permanent magnets of both units are fixed in close contact with each other with their end faces facing each other as a pair. It is a magnet device in which each pair of permanent magnets is magnetized so as to have two polarities on the same plane.

Here, it is preferable to use permanent magnets located at both ends of the permanent magnet array of each unit that have a larger coercive force than the inner permanent magnets.

To manufacture such a magnet device, for example, a plurality of unmagnetized permanent magnets are fixed to a first non-magnetic support member at predetermined intervals to form a first unit, and the same number of Place the unmagnetized permanent magnet into a second non-6n magnet at the same spacing as in n1.
It is fixed to the gender support member as a second unit, and each Uniso 1
- The permanent magnets are magnetized at once in their thickness direction, and then the end faces of the corresponding permanent magnets of both units are faced to each other, and each pair of permanent magnets is tightly fixed on the same plane so that it has two polarities. be.

Here, if a synthetic resin is used for the first and second non-magnetic support members and one end of each permanent magnet is embedded and fixed using an insert mold of the synthetic resin, each unit can be assembled easily with high precision.

A printing device can be constructed by arranging a driving element of a moving coil type impact dot printer within the gap between adjacent permanent magnets of such a magnet device.

[Function] As described above, the present invention is configured such that the end surfaces of the pairs of permanent magnets in both units face each other and are in close contact with each other.
The close contact side is new!・The neutral zone becomes extremely sharp, and the positional accuracy of the neutral zone can be increased.

In the present invention, since each permanent magnet is in an unmagnetized state when attached to the non-magnetic support member, assembly work is much easier and assembly accuracy is also increased.

It is also possible to use an insert mold method, which further reduces the number of work steps. Since each unit may be magnetized so that each permanent magnet has one polarity in the thickness direction, magnetization can be easily performed at one time using, for example, an air-core coil type magnetizing device.

Furthermore, since magnetization is performed after assembly using unmagnetized permanent magnets, it is possible to change the material properties of the permanent magnets located at both ends of the permanent magnet array and the permanent magnets located inside. In other words, since magnetization is performed after assembly, the inner permanent magnet will not be in a low permeance state. Therefore, if permanent magnets with a large coercive force are used as the permanent magnets at both ends, it is possible to use a permanent magnet with a large residual magnetic flux density even if the coercive force is small as the inner permanent magnet.

As a result, the air gap magnetic flux density in the gap between the permanent magnets is reduced to 1, and the magnetic properties are improved.

Furthermore, in the present invention, since each unit is assembled without attachment, automatic cleaning can be carried out, and workability is significantly improved in this respect as well.

[Example] The first drawing shows an example of a magnet device according to the present invention, and FIGS. 1A to 1C show an example of a manufacturing method thereof.

This magnet device consists of a first unit 34 in which a plurality of plate-shaped permanent magnets 30 are arranged in parallel on a first non-magnetic support member 32 in a state where they are erected at regular intervals, and the same number of plate-shaped permanent A second unit 40 has magnets 36 erected at the same spacing as above and arranged in parallel on a second non-magnetic support member 38, and the corresponding permanent magnets 30, 36 of both units 34, 40 are paired and their tips are The permanent magnets 30 and 36 are fixed in close contact with each other with their surfaces facing each other, and the pair of permanent magnets 30 and 36 that face each other in close contact are magnetized so as to have two polarities on the same plane.

Therefore, the contact surface between the permanent magnet 30 of the first unit 34 and the permanent magnet 36 of the second unit 40 just becomes a neutral zone.

This magnet device is used in a moving coil type impact dot printer to apply a driving magnetic field to its driving element. Although detailed illustrations are omitted, for example, similar to the prior art shown in FIG. , a dot bin, etc., and the dot bin is driven by the interaction between the drive current flowing through the flat movable coil and the magnetic field applied to the gear to perform printing.

Such a magnet device can be easily manufactured by the manufacturing process shown in FIGS. 1A to 1C. First, as shown in FIG. A, plate-shaped unmagnetized permanent magnets 30 are arranged at regular intervals and fixed to the first non-magnetic support member 32 to form a first unit 34, and the same number A second unit 40 is constructed by fixing the plate-shaped permanent magnets 36 to the second non-magnetic support member 38 at the same intervals as described above. These non-magnetic support members 32, 38 are made of synthetic resin such as polyethylene terephthalate (PET), and after each unmagnetized permanent magnet 30, 36 is temporarily held using a jig or the like, a printed dot pin is inserted. One end is forever! (2) The first and second units 34 and 40 are formed by insert molding the synthetic resin into a structure in which the end face is the same as the stone, and the other end is provided with a flange so that it can be fixed to a structural member of the printing device. Of course, adhesive may be used, but it is preferable to use the insert molding method because it allows for efficient and highly accurate assembly.At this time, grooves are formed in the part of the permanent magnet to be molded to prevent the permanent magnet from falling off the non-magnetic support member. It is preferable to provide a reinforcing triangular part on the end face of the permanent magnet on the flange side.

Permanent magnets include rare earth sintered magnets, rare earth bonded magnets,
Alternatively, any material such as a metal magnet can be used.

Next, the first and second units 34, 40 assembled in this manner are installed in the magnetizing device 42, and are magnetized at once in the thickness direction of each permanent magnet. Here, magnetization is performed by supplying pulsed current using an air-core coil type magnetizing device, but the direction of zero magnetization may also be configured by using a suitable yoke and magnetizing by direct current. both units 3
4. When the 40s are placed facing each other as shown in Figure 1C, both permanent magnets should have opposite polarities.

Then, as shown in FIG.
A magnet device as shown in the figure is obtained.

However, in the conventional manufacturing method, 61 permanent stones were magnetized one by one and then assembled into each unit, so the permanent magnets were isolated and a low permeance state always existed. Therefore, all permanent magnets needed to have a large coercive force in order to meet their intended use. However, according to the present invention, after assembling the unit using unmagnetized permanent magnets, the entire unit is magnetized at once, so the permanent magnet placed inside is in a high permeance state because there are other permanent magnets on both sides. Therefore, the permanent magnets located at both ends of these inner permanent magnets do not require a large coercive force.

By the way, in the case of permanent magnet materials of the same material series, it is known from experience that increasing the residual magnetic flux density Br and increasing the coercive force bHc are in an antinomic relationship. In the present invention, if a material with a large coercive force is used for the permanent magnets on both sides, a permanent magnet with a large residual magnetic flux density can be used on the inner side even if the coercive force is small, and as a result, the operating point magnetic flux density at the same permeance is This increases the air gap magnetic flux density between the permanent magnet gaps and improves the magnetic properties.

Therefore, for example, in the magnet device shown in the first diagram, it is possible to use a combination such as using rare earth sintered magnets on both sides and rare earth bonded magnets on the inside.

[Effects of the Invention] The present invention has a unit in which a plurality of permanent magnets are arranged side by side, and the corresponding permanent magnets of each unit are fixed as a pair with their end faces facing each other and in close contact with each other, and the pairs of facing permanent magnets are the same. Since the magnet device is magnetized to have two polarities on a plane, the surfaces in which the permanent magnets are in close contact with each other become the neutral zone, and there is an effect that a sharp neutral zone can be formed with high positional accuracy.

Furthermore, since the present invention assembles the unit using unmagnetized permanent magnets, there is no influence from the magnetic force of adjacent permanent magnets when positioning and fixing, improving assembly accuracy. Workability is improved because it can be magnetized.

Further, if the permanent magnet is fixed to the non-magnetic support member by insert molding, workability and assembly accuracy are further improved.

In the present invention, among the permanent magnet arrays of both units, the permanent magnets located at both ends have a large coercive force, and the inner side can use permanent magnets with a high residual magnetic flux density even if the coercive force is small. Therefore, it is easy to magnetize (also, the magnetic flux density between the permanent magnet gaps can be improved, and the magnetic properties can be improved).

[Brief explanation of the drawing]

1A to 1D are explanatory diagrams showing an example of the manufacturing process of a magnet device according to the present invention and the magnet device obtained thereby, FIG. 2 is an explanatory diagram showing an example of a conventional magnet device, and FIG. 3 is an explanatory diagram showing an example of the magnet device obtained thereby. 1 is an explanatory diagram showing the main parts of a moving coil type impact dot printer using a moving coil type impact dot printer. 30... Permanent magnet, 32... First non-magnetic support member, 34... First unit, 36... Permanent magnet, 3
8... Second non-magnetic support member, 40... Second unit, 42... Magnetizing device.

Claims (5)

[Claims] 1. A first unit in which a plurality of permanent magnets are erected on a first non-magnetic support member at predetermined intervals, and the same number of permanent magnets are erected on a second non-magnetic support member at the same intervals as above. The corresponding permanent magnets of both units are fixed in close contact with each other with their end faces facing each other, and each pair of permanent magnets is magnetized on the same plane so as to have two polarities. A magnet device characterized by: 2. 2. The magnet device according to claim 1, wherein the permanent magnets located at both ends of the permanent magnet array of each unit have a larger coercive force than the inner permanent magnets. 3. A plurality of unmagnetized permanent magnets are placed at a predetermined interval.
fixed to a non-magnetic supporting member to form a first unit, and fixing the same number of unmagnetized permanent magnets to a second non-magnetic supporting member at the same intervals as above to form a second unit,
The permanent magnets of each unit are magnetized at once in the thickness direction,
The manufacturing of the magnet device according to claim 1 or claim 2, characterized in that the end surfaces of the corresponding permanent magnets of both units are then faced and closely fixed so that each pair of permanent magnets has two polarities on the same plane. Method. 4. The first and second non-magnetic support members are made of synthetic resin,
4. The method of manufacturing a magnet device according to claim 3, wherein each permanent magnet is fixed by an insert mold of the synthetic resin. 5. 3. The magnet device according to claim 1, wherein a driving element of a moving coil type impact dot printer is arranged in the gap between adjacent permanent magnets.