JPH0753899B2 - High frequency magnetic core material made of Fe-based alloy - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a head core and a plunger yoke material for a dot printer, and a stator and a rotor for a stepping motor, which are made of an Fe-based alloy having excellent high-frequency AC magnetic characteristics. The present invention relates to a high frequency magnetic core material.

[Conventional technology]

In general, these high-frequency magnetic core materials are particularly resistant to heat generation due to eddy currents induced in the magnetic core materials during practical use.
It has a relatively high electrical resistance (which usually means that the eddy current loss P associated with heat generation of the material is However, K: shape factor, B: magnetic flux density, f: frequency, ρ: electrical resistance, which is proportional to the square of the frequency and inversely proportional to the electrical resistance), and has a high magnetic flux density. In addition to having a small magnetic loss, in addition, by weight% (hereinafter% means% by weight), Si: 2 to 3.5%, and the rest is a Fe-based casting alloy having a composition consisting of Fe and inevitable impurities. Being manufactured.

[Problems to be solved by the invention]

On the other hand, in recent years, for example, in word processors, further speeding up and clearer printing have been avoided. However, the conventional Fe-based cast alloy magnetic core material described above does not have sufficient high-frequency magnetic characteristics, so that it is not possible to satisfy this requirement. The current situation.

[Means for solving problems]

Therefore, the inventors of the present invention have conducted research to develop a high-frequency magnetic core material having more excellent high-frequency magnetic characteristics from the above viewpoints. As a result, Si: 1 to 5%, C: 0.1 ~ 0.6%, and, if necessary, Mn: 0.05 to 1%, with the balance consisting of Fe and unavoidable impurities, and 5% to 30% pearlite by volume on the basis of ferrite. The high-frequency magnetic core material composed of an Fe-based alloy having a phase-dispersed structure has higher high-frequency magnetic properties than the conventional Fe-based casting alloy high-frequency magnetic core material, Since the amount of heat generated by eddy currents is extremely small, we have found that it is possible to sufficiently cope with higher speeds and higher performance of equipment.

The present invention has been made based on the above findings, and the reasons why the component composition and the ratio of the pearlite phase are limited as described above will be explained below.

(A) Si The Si component is solid-dissolved in the matrix to increase its electrical resistance,
It also has the effect of improving high-frequency magnetic properties, but if its content is less than 1%, the desired effect cannot be obtained, while if it exceeds 5%, embrittlement tends to occur. Then, since the machining becomes difficult, the content thereof is set to 1 to 5%.

(B) The C component has an action of forming a pearlite phase in the base material of ferrite and further improving high frequency magnetic properties, but if the content is less than 0.1%, the pearlite phase dispersed in the base material Since the ratio is less than 5% by volume, the desired high frequency magnetic property improving effect cannot be secured, while when the content exceeds 0.6%, the ratio of the pearlite phase becomes 30% by volume. Therefore, the content was determined to be 0.1 to 0.6% because the high-frequency magnetic properties deteriorate again.

(C) Mn The Mn component has a deoxidizing action, and the high-frequency magnetic properties are improved by this deoxidizing. Therefore, it is contained especially when deoxidizing is required at the time of melting and casting. Its content is
If it is less than 0.05%, the desired deoxidizing effect cannot be secured, while if it exceeds 1%, the high frequency magnetic properties tend to deteriorate, so the content should be 0.05 to 1%. I decided.

(D) Volume ratio of pearlite phase By incorporating the pearlite phase in the ferrite body as described above, the high frequency magnetic properties are remarkably improved. However, when the volume ratio is less than 5%, it is desirable. Since the effect of improving the high frequency magnetic properties cannot be obtained, and the desired high frequency magnetic properties cannot be exhibited even if the ratio exceeds 30% by volume, the ratio is determined to be 5 to 30% by volume.

In the production of the magnetic core material of the present invention, powder metallurgy, hot rolling or forging, etc. can be applied.

〔Example〕

Next, the high frequency magnetic core material of the present invention will be described with reference to examples.

Using a normal high-frequency melting furnace, see Table 1 for each. A molten metal having the composition shown below was prepared and cast on a dot core (9 pins) of a dot printer as a high frequency magnetic core material, and subsequently held in a vacuum heat treatment furnace at 950 ° C for 1 hour and then cooled in a furnace. After the above, the dough cores 1 to 12 of the present invention were manufactured by finishing the final shape.

For the purpose of comparison, the conventional dot cores 1 to 3 were manufactured by preparing a molten metal having the same composition as shown in Table 1, immediately casting, and finishing the final shape.

Next, regarding the various types of dot cores obtained as a result,
Using two each, accurately stack the pins of the dot core via a non-magnetic material with a thickness of 0.3 mm, wind a coil around the pin of one of the dot cores, energizing cycle: 50Hz, voltage between coil terminals : 40 V, energizing time: 140 μs, magnetomotive force (Ni): 150 ampere turn (current x number of coil turns), a rectangular wave pulse voltage is applied between coil terminals,
At this time, the magnetic flux Φ flowing through the pin of the dot core was measured.

The height of the dot core pin is 10 mm × effective area: 0.
It has a rectangular shape of 15 cm ² × width: 2.6 mm, and the magnetic flux Φ is
Measure with a search coil, use a waveform analyzer, However, Ns: number of turns of search coil (= 3), e: induced voltage between search coils, was calculated by the following formula. The results are shown in Table 1.
Table 1 also shows the volume ratio of the pearlite phase dispersed in the matrix.

〔The invention's effect〕

From the results shown in Table 1, the present invention dot cores 1 to 12 having a structure in which the pearlite phase is dispersed in the ferrite base material.
Is a conventional dot core 1 whose base material is a ferrite structure.
It is clear that the high frequency magnetic characteristics are more excellent than those of the above-mentioned materials.

As described above, since the high-frequency magnetic core material of the present invention has extremely high-frequency magnetic characteristics, it can sufficiently support high speed and high performance of dot printers, stepping motors, and the like, and has excellent performance. Is to demonstrate.

Claims (2)

[Claims] 1. A composition containing Si: 1 to 5%, C: 0.1 to 0.6%, the balance being Fe and unavoidable impurities (more than weight%), and a ferrite base material having a volume ratio of 5 to 30.
% Fe-based alloy core material having a structure in which pearlite phase is dispersed. 2. A composition containing Si: 1 to 5%, C: 0.1 to 0.6%, and further, Mn: 0.05 to 1%, with the balance being Fe and inevitable impurities (above weight%). , And ferrite substrate, volume ratio of 5-30
% Fe-based alloy core material having a structure in which pearlite phase is dispersed.