JPS5968117A - Lead switch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (a1 Technical Field of the Invention The present invention is a glass tube in which lead pieces made of magnetic material are sealed from both ends, and contacts are opened and closed at mutually overlapping parts of the lead pieces. Regarding switches.

Background of FBL Technology In a typical reed switch, as shown in Figure 1 (a), a pair of lead pieces 2'' and 3'' are inserted from both ends of a glass tube l, and the switch is sealed in an inert gas atmosphere. Then, when the excitation coil 4 placed outside the glass tube 1 is energized, the magnetic flux passing through both the reed pieces 2° and 3° closes the gap 5 at the overlapped contact portion of the reed pieces, turning on the °ζ switch. Next, when the excitation coil 4 is de-energized, the magnetic attraction force of the contact gap 5 disappears, the contact gap 5 opens, and the switch is turned off.

The contact part at the inner end of the lead piece is connected to the lead piece 3 as shown in (b).
A contact point 6'' made of a noble metal material is provided at the tip of ``ζ''(2') to reduce contact resistance. Permalloy, especially an alloy phase of 52% nickel and 48% iron called 5270i, is widely used as the magnetic material for the reed piece. As the contact material, materials such as gold, silver, rhodium, copper, or gold thread alloy (Au-co, Au-N1) are used.

(C1 Prior art and its problems) However, when a soft material such as gold or silver is used as the contact LTA material, the excitation coil 4 is de-energized and the excitation magnetic field is removed due to the adhesive phenomenon between the contact materials. Also, the contact gap 5 tends to remain closed.In order to prevent this, after plating the contact material on the lead piece, heat treatment is performed for about 20 minutes in an electric furnace in a hydrogen atmosphere. is diffused so that a portion of Shimoike metal precipitates on the surface of the contact.

However, although this method reduces adhesion to some extent, it has the following drawbacks.

(11 Due to Fe in permalloy, the surface of the contact is easily oxidized and the contact resistance is likely to become unstable. In other words, an oxide film of Fe-Ni is formed and iron and oxygen coexist, so the boundary resistance (
This results in a higher level of contact resistance than rhodium (Rh) contacts.

(2) Due to a small amount of residual oxygen in the glass tube of the reet switch, an oxide film is formed by the iE thrust energy when the contact closes during no-load operation, and increases with the number of operations. In other words, as the number of operations increases, the bridge wears out, i.e., p
It generates ip & crater, increases contact resistance, and reduces adhesion (
This may cause contact problems such as sticking. The reason is that when current flows between closed contacts, the temperature rises due to Joule heat, which softens the contact surface and reduces viscosity. Moreover, since the positive side becomes hotter than the negative side, the softened contact material on the positive side sticks to the cold negative side contact, causing bridge wear on the positive side and creating a depression. In addition, ions generated on the negative side due to a short arc during energization collide with the positive side contact surface, and the powder generated at that time is deposited on the negative side contact surface, further promoting depressions and protrusions. When the protuberance fits into this recess, it becomes locked and adheres, making it difficult to separate the contacts when the excitation magnetic field is removed. These phenomena are particularly likely to occur in a region of about 50V1100m8.

In addition to this method of diffusion treatment, by mixing approximately 3% CO into the gold plating solution and performing alloy plating, so-called hard gold containing 3% CO mixed on the entire surface of the contact material can be formed. obtained, and the adhesion resistance is improved. Furthermore, since unoxidized Fe does not appear on the contact surface, the contact resistance is improved compared to the case where the 52 alloy and the gold plating are subjected to diffusion treatment.

However, unlike those subjected to diffusion treatment, the bond between the alloy-plated contacts and the underlying 5270I is weak, and the contacts tend to peel off due to repeated temperature changes. In particular, the electrical resistivity of 5270I is as high as 35 μΩ·cm, so the current passing through the contact generates a large amount of heat, and the contact is subjected to high-temperature cycles, making it even more likely to peel off.

In order to solve such problems, the applicant of the present invention has
Fe(
10-18%)-Co(balance) alloy was proposed. When this magnetic material is used, it contains 82 to 90% Co, so if it is gold-plated as a contact material and then subjected to a diffusion treatment, CO, which is easily oxidized, will not precipitate, so it will oxidize and contact The resistance does not increase, and the adhesion between the contact material and the piece is improved.

However, when Fe (10 to 18%) - Co (remainder) alloy is used, another problem is that if the deburring performed before the coating process is performed by electrolytic polishing, the contact material and one piece are The adhesion of the product deteriorates, and the desired effect cannot be obtained. That is, as shown in FIG. 2, the dust-1" piece is formed by flattening a part of the round bar 7 with a press to form a plate shape, and a contact point is provided at the tip of this plate part 71. If barriers 2 or burrs generated during processing or cutting remain on the tip of the lead piece, this will interfere with the opening/closing operation of the contact and reduce the reliability of the contact operation.In order to remove this burr, mechanical methods are used. As a method of barrel polishing, there is a method called barrel polishing in which the abrasive is stirred together with the abrasive, but with this method there is a risk that the beam 1 and one eye may be deformed.Also, during barrel polishing, the beam pieces are broken apart and the abrasive is Since it is mixed with
Handling is difficult and workability is poor when transitioning to the wood cutting process. On the other hand, the electropolishing method requires only immersion in an electrolytic solution, so unlike barrel polishing, which uses mechanical stirring, the lead pieces do not collide with each other and cause deformation, and can be held in a constant state. It is easy to handle and has excellent workability when moving on to the next metal/noki process.

By the way, electrolytic polishing of 5270i requires a phosphoric acid concentration of 50~
A 70% phosphoric acid solution (FI3PO1) is used as the electrolytic polishing solution, but a similar phosphoric acid solution containing less than 20% Fe
e (10-18%>-CO<remainder) When an alloy is electrolytically polished, the polished surface tends to be rough, and electrolytic pits and minute depressions are likely to occur. Therefore, Fe containing a large amount of CO (
Even if the (10 to 18%) -Go (remainder) alloy is used, it will impede the adhesion between the contact material and the lead piece in the subsequent coating process, making it impossible to achieve the intended purpose.

(d) Purpose of the Invention The present invention solves these problems in the conventional glued switch, and realizes a reed switch that has good adhesion between the reed piece and the contact, is less prone to adhesion, and has low contact resistance. The purpose is to

te1 Structure of the Invention In order to achieve this object, the present invention has a phosphoric acid concentration of 90%.
Fe deburred by electrolytic polishing with phosphoric acid solution of % or more
A structure is adopted in which a lead piece made of a ferromagnetic material of (10 to 18%)--Co (remainder) alloy is sealed in a sealed container with a contact attached to its contact portion.

(f1 Embodiment of the Invention Next, how the reed switch according to the present invention is actually embodied will be explained by way of an embodiment. FIG. 3 is a sectional view showing the reed switch according to the present invention. Piece 2
．． 3 is ζFe (10-18%) in place of 52A1 carp.
It was composed of a Co (residue) alloy. And Konori-1! Piece 2.
3 is pressing] After pressing, the contact material is electrolytically polished with a phosphoric acid solution having a phosphoric acid concentration of 90% or more to remove deburrs and improve the surface condition, and then the contact material is plated and diffused. Reference numeral 6 denotes a contact point made by gold plating and diffusion treatment on the tip of the FB (10-18%)-Co (remainder) alloy paste-I' piece 2.3. Furthermore, the glass cage is filled with argon as an inert gas.

FIG. 4 is a block diagram showing the manufacturing method of this reed switch in order of steps. First, Fe(10-18%)-CO<
(Remaining) Press the alloy round bar to flatten the portion to be enclosed in the glass tube 1 to obtain predetermined elastic properties. Next, after cutting to a predetermined length, heat treatment (annealing) is performed under predetermined conditions in order to recover the deterioration of magnetic properties caused by pressing.

Then, the lead piece 2.3 is electrolytically polished using the method of the present invention. The electropolishing conditions are such that a phosphoric acid solution having a phosphoric acid concentration of 90% or more is used.

In other words, the reason why the surface condition deteriorates when electrolytically polished under the same conditions as 5270I is thought to be because the oxide film formed by anodizing the Fe-Co alloy is less uniform than that of the 52 alloy, and the elution of CO becomes more intense. It will be done. Therefore, the composition of the electrolytic polishing solution was changed to a concentrated phosphoric acid solution with a phosphoric acid concentration of 90% or more (If
fi PO+ ), and additives containing ethylene glycol or the like as a main component are added as necessary. Electrolytic polishing is then performed using the lead piece as an anode.

Fe (10-18%)-Co with such a concentrated phosphoric acid solution
When the (remaining) alloy was electrolytically polished to remove burrs, no focusing occurred and a uniform condition with no surface roughness was obtained compared to those electrolytically polished with a conventional electrolytic polishing solution.

The lead pieces that have been sharpened in this way are plated with a contact material such as gold. As mentioned above, the surface of the reed piece is made uniform by the concentrated phosphoric acid solution, so the adhesion of the plating is sufficient.The reed piece plated with contact material is further heat-treated to bond the contact material and -(・Perform diffusion between pieces.

That is, the piece 2.3 on which the contact material is plated is placed in a furnace at a temperature of ζ800±100'C for 15 to 60 minutes.
Heat treated in hydrogen (I(2)) and added 3 to 1 Co on the contact surface.
0% atomic weight diffusion. As mentioned above, the adhesion of the plating is improved by deburring with concentrated phosphoric acid solution, and since the gap between the lead piece and the contact material is subjected to diffusion treatment, the adhesion between the lead piece and the contact material becomes even more reliable. .

Finally, it is sealed in a glass tube in an argon gas atmosphere.
The entire manufacturing process is completed by performing the inspection.

FIG. 5 shows the relationship between the amount of Co precipitated, the adhesive property, and the contact resistance when the Go in the lead piece is diffused to the surfaces of all the contacts as described above. The horizontal axis is Co applied to all contact surfaces.
The amount of precipitation (%), the vertical axis is the adhesive property (magnetostriction test open value change rate) and contact resistance value. When the Co diffusion amount is 3% or more, the magnetostriction test open value change rate is 20% or less, and the adhesiveness is greatly improved. On the other hand, the contact resistance is preferably all gold because the amount of CO diffused is small, but if the amount of precipitation is 6% or less, the contact resistance is almost the same as 30Ω in the case of only gold.

Up to about 10%, it becomes 60Ω or less, which does not pose much of a problem in practice.

Figure 6 shows an enlarged view of the Fe (10-18%)-Go (remainder) alloy.
This is a diagram showing the relationship between the i& treatment temperature and time and the amount of CO precipitated, where the horizontal axis is the annealing temperature and the vertical axis is the amount of Co precipitated. As mentioned above, both adhesion and contact resistance show acceptable values c o +i
The amount of a is about 3 to 10%, but in order to obtain this amount of Co precipitation, when the annealing time is 15 minutes, it is about 700 to 10%.
A temperature of about 900°C is appropriate and for 60 minutes, 76
A temperature of 0°C or lower is suitable.

Figure 7]? This is a diagram showing the coefficient of thermal expansion of an e-Co alloy, where the horizontal axis is the content of iron (Fe) in cohar l-(Co), and the vertical axis is the thermal expansion coefficient. Fe-Co alloy glue-1/piece 2.3
In order to seal directly to the glass tube l, the reel l'' piece 2.3
In order to prevent a crank from occurring in the glass tube when it is sealed to the glass tube 1 in the same way as the conventional 5270I,
It is required that the saw 1' piece 2.3 and the glass tube 1 have the same coefficient of thermal expansion.

In the case of an Fe-Co alloy, the coefficient of thermal expansion i8 is approximately equal to that of a glass tube depending on the Fe content.

7 In other words, the coefficient of thermal expansion of the glass tube is 117.5±2.5X 10
/°C, but the Fe-C used in the present invention.

The alloy has a thermal expansion coefficient comparable to that of glass in the range of Fe content of 8.5 to 20%.

FIG. 8 is a J diagram showing the electrical resistivity of the Fe--Co alloy, where the horizontal axis is the iron (Fe) content in cobalt (Co), and the vertical axis is the electrical resistivity. The coefficient of thermal expansion is equal to that of glass: 8.5~
In the 20% Fe region, the electrical resistivity is 12-14 μΩc
The electrical resistivity is about 35 μΩcm, which is far superior to the 35 μΩcm of 52 alloy, which is a conventionally widely used REIT abrasive material. As described above, since the Fe--Co alloy has a low electrical resistivity, the temperature rise when energized is small, and it was confirmed that it is superior to the 52 alloy.

Figure 9 is a diagram showing the resistance change rate with respect to the current value of the 12%Fe-88%CO alloy and the 52 alloy.
88% Co alloy is better than 52 alloy. 1st
Figure 0 is 12%Fe-88%C.

This is a hysteresis curve showing the magnetic properties of the alloy.

The above characteristics are summarized in Table 1.

Table 1 Figure 11 shows the conventional 5270I and the present invention Fe(10
~18%)-Co (remainder) alloy shavings were compared with nitrogen (N2) encapsulation and argon (A) according to the present invention.
r) A diagram comparing the case of inclusion. As is clear from this figure, the Fe (10-18%)-Co (remainder) of the present invention
-F switches using alloys are superior to conventional argon-sealed ones even when sealed with nitrogen;
(10 to 18%) -Co (remainder) The effect of the alloy properties appears. In addition, Fe (10 to 18
%)-Co (remainder) alloy paste has a longer lifespan than that sealed with nitrogen.

(G1 As is clear from the characteristic diagrams described above, Fe(10 to 1
8%) -Co (remainder) alloy has excellent sealing properties with glass tubes, electrical properties, magnetic properties, etc., and its properties as a lead piece are more promising than 52 alloy. The present invention deburrs a piece of Fe (10 to 18%) -〇〇 (remaining) alloy paste by electrolytic polishing with a concentrated phosphoric acid solution to make the surface condition uniform and to form a contact point on the piece. It has a structure in which the material is punched and treated with an enlarged nt. Therefore, unlike 5270I, the amount of precipitated Fe that worsens contact resistance is small, and CO, which is stable against oxidation, is precipitated, so contact resistance is extremely low, and oxidation is further suppressed by argon sealing, resulting in an extremely long life. becomes. In addition, since cobalt is precipitated to the contact surface, the adhesion of the contact is improved, the surface roughness when removing the lead piece is improved, and the IJ-1 piece and the contact material are diffused.
The adhesion between the contact material and the lead piece is also extremely good, resulting in an even longer life.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the overall structure and contact portion of the energized reed switch, Fig. 2 is a diagram showing the process of deburring the reed piece,
FIG. 3 is a sectional view showing a reed switch according to the present invention, and FIG. 4 is a process diagram showing Step 2 of manufacturing the reed switch according to the present invention. Figure 5 and the following diagrams show the initial characteristics of the reed switch according to the present invention; Figure 5 shows the adhesive properties and contact resistance characteristics; Figure 6 shows the relationship between the annealing temperature and time and the amount of CO precipitated; FIG. 7 is a diagram showing the relationship between Fe content and thermal expansion coefficient, FIG. 8 is a diagram showing the relationship between Fe content and electrical resistivity, and FIG. 9 is a diagram showing the relationship between Fe content and electrical resistivity. A diagram showing the resistance change rate of alloys, Figure 10 is 12Fe, Co
FIG. 11, which is a diagram showing the hysteresis curve of the alloy, is a diagram showing the life characteristics depending on the difference in filled gas. In the figure, ■ is a glass tube, 2.3 beam-1 piece, 4 is an excitation coil, 5 is a contact gap, 6 is all contacts, 71 is a flat part of beam-1 piece, and 72 is a paris, respectively.

Claims (1)

[Claims] (11 Fe (10 to 18%) deburred by electrolytic polishing with a phosphoric acid solution with a phosphoric acid concentration of 90% or more) -C. A reed switch characterized in that the contact portion is covered with a contact and is enclosed in a sealed container. (2) The sealed container is filled with argon gas. (Node described in Section 11) S switch.