JPS5960820A - Current 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 [Technical Field of the Invention] The present invention relates to a current switch, particularly a current switch suitable for switching medium currents.

[Technical background of the invention]

In a current switch comprising electrical contacts facing each other,
For example, Ag and Ag-Ni are suitable for switching medium currents of about 10 to 100 A.

Ag-Cd0+ Ag-ZnO, Ag-In2O3+
Ag-8n02 (Ag is silver, Nl is nickel, c
d is cadmium, 0 is oxygen, In is indium, and Sn is tin. ) and other electrical contacts (both poles made of the same material) are in practical use.

However, when using Ag contacts, the contact resistance is extremely low and the hardness is small, so while there are advantages such as less chattering during input, there are disadvantages such as poor wear resistance and welding resistance. In the case of Ag-N electrical contacts, the welding resistance and abrasion resistance are improved compared to pure Ag contacts, and the contact resistance is stable enough to be comparable, but the welding eye field current is low compared to other contacts. .

On the other hand, Ag-Cd0. In the case of contacts such as Ag-ZnO,
The above-mentioned contacts have the advantage that they can be applied to current fields where they cannot be covered, but in that case, welding and wear are large, and there is a need for improved durability. Also, Ag-S nO2,
Contacts made of Ag--In2O3 and the like have excellent wear resistance, but are inferior in terms of contact stability and cannot be said to be sufficient.

Furthermore, we are also experimenting with technology that uses a combination of different materials, such as one contact made of C (carbon)-Cu (copper) and the other made of Cu, for current switches used in elevators, vehicles, etc. It is being

In this case, attempts were made to reduce or suppress the welding phenomenon by utilizing the phenomenon of low wettability between C element and other metals. Disadvantages are recognized, such as being large and having poor contact characteristics.

By the way, even in this type of current switch, miniaturization and long life are required from the viewpoint of saving resources and energy, and high performance and long life are required for contacts and contact materials. It is rare.

[Purpose of the invention]

The present invention was developed in view of the above circumstances, and has stable contact characteristics and excellent wear resistance, can maintain nine-point performance over a long period of time, and is particularly suitable for medium current switching. The purpose is to provide a switch.

[Summary of the invention]

That is, in order to achieve the above-mentioned object, the present invention makes at least the contact surface of the electrical contact of one opposing pole made of Ag-oxide based material, and at least the contact surface of the electrical contact of the other pole made of Ag-N1 based material. The material is made of a material such that wear resistance and stable contact characteristics can be obtained by taking advantage of the features of Ag-Ni-based materials and the features of Ag-oxide-based materials.

[Embodiments of the invention]

As a result of conducting studies to address the above-mentioned demands, the inventor has found that
In order to demonstrate the stable contact characteristics of Ag-Ni (nickel) based contacts even at higher currents and improve the wear resistance of the contacts, this can be achieved by using them in combination with Ag-oxide based contacts. I confirmed that it can be done.

The present invention is based on this and will be explained in detail below.

The present invention provides a current switch having electrical contacts facing each other, in which at least one contact surface of one of the electrical contacts facing each other is
At least the contact surface of the other opposing electrical contact is made of Cd, Zn,
Inr 8n, at least one oxide of Sb 2~
The current switch is characterized in that it is constructed of an Ag alloy containing 15% by weight.

FIG. 1 is a sectional view showing an example of the configuration of a current switch according to the present invention. Reference numeral 1 denotes a movable base metal Ql that forms a part of the current path.
is connected to

Furthermore, the movable base metal 1 and the movable frame 2 are locked together by a contact spring 3, and when no external force is applied, the movable base metal 1 is always moved in one direction (arrow 4) by the contact spring 3. direction).

Further, fixed contacts 7m are provided at the ends of the conductive pieces 5m and 5b connected to an external electric circuit.

Movable contacts 6* and 6b are provided at both ends of the movable base metal 1 so as to be opposed to the movable base metal 5-7b.

Then, the movable frame 2 brings the movable contacts 6m, 6b into contact with the fixed contacts r*, 7b by attracting the iron cores 12a, 12b to which a current is applied to the excitation coil 1, thereby causing the electrical contact device to It operates as if it were turned on.

A contact plate spring 8 is provided on the movable contact side in order to absorb the dynamic movement that occurs when the movable contact 6a and the fixed contact 7a and the movable contact 6a and the fixed contact 7b come into contact. In addition, a grid 9 for extinguishing the arc generated between both contacts is provided on the main body 1.
It is attached to 0.

One of the electrical contacts facing each other in the figure, for example, the movable contact 6
M, 6b has a diameter of 5 m and a thickness of 1.5 wa, and is made of an Asr-based alloy in which Ni of 5 weight coefficient or more is dispersed. The other electrical contacts facing each other, namely fixed contacts 7m and 7b, have a diameter of 5.5 m and a thickness of 1.5 m.
It is made of a 61Ag-based alloy in which Sn+ 8b oxides are dispersed. However, in the above, A
The composition ratio of Nl in the g-N1 system is limited to the lowest 5 weight ratio. The reason is that when combined with Ag-oxide contacts, N
When i is less than 5, there is no significant difference in welding resistance compared to pure Ag, and the effect of improving wear resistance is insufficient.

In addition, the upper limit of Ni is determined by the design values of the contact force, opening force, etc. of the current switch and cannot be clearly defined, but the tendency is that the more Ni there is, the higher the temperature rise value, and the higher the contact resistance value. It also becomes more expensive.

On the other hand, in Ag-oxide type contacts, if the composition ratio of each oxide is less than 5%, when combined with Ag-Ni type, welding failure is likely to occur and the effect of improving wear resistance is low. Furthermore, if the amount of oxide exceeds 15% by weight, the contact resistance between both contacts will be high and cracks will occur during molding of the Ag-oxide contact, which will ultimately result in the desired effects of the present invention not being achieved. This is because it cannot be done. Note that the entire contact does not need to be made of these alloys; it is sufficient that at least only the contact surface is made of the above-mentioned alloy.

7- As described above, in the current switch according to the present invention, the electrical contacts facing each other are composed of a combination of different types of Ag alloys, and in particular, the contact material made of Ag alloy containing oxides is reduced in weight by switching the current. The technology of the present invention exhibits its performance more effectively if it is installed on the polar side that shows more. Thus,
Advantages of Ag-Ni alloy contacts and Ag-Cd0. Ag
-ZnO,Ag-8n02+ Ag-In2O3,Ag
-5b2o, the advantages of each alloy have been utilized to achieve contact characteristics that are excellent in welding resistance, abrasion resistance, and low contact resistance characteristics, and can perform the required functions as a current switch for a long time. It's going to be a long time ago.

Examples of the present invention will be described below.

-The following are examples. First, after mixing predetermined amounts of Ag% and Ni, 15 WrIRX 15 m
It is molded into a size of x800m and pre-sintered in hydrogen at 700°C for 2 hours to produce a pre-sintered body. Next, 700 in hydrogen
The pre-sintered body was reheated at 50° C. for 5 minutes and subjected to a swager process, and this operation was repeated 4 times to finally obtain a rod-shaped contact with a diameter of 8 pieces.

8- This was cut out to a thickness of 4mm and used as one contact point. In addition, after alloying Ag, CD, Zn + 8n + In, and sb in a predetermined composition ratio, it was molded and heated at 700°C in an oxygen atmosphere of 4 atm for 4 days (for Ag-Cd and Ag-Zn systems). Alternatively, internal oxidation treatment was performed for 8 days (in the case of Ag-In and Ag-8n systems) to produce a contact piece having a diameter of 8 m and a thickness of 4 m and having the composition ratio shown in Table 1. Of the electrical contacts obtained in this way, the Ag-Ni type was installed as the fixed side contact of the current switch shown in the figure, and the Ag-oxide type was installed facing each other as the movable side contact of the same switch. The amount of wear (difference in weight before and after opening and closing) of each electrical contact was measured using a microbalance when opening and closing operations were performed 5X10' times at 2OA and a power factor of 0.8, and the results are also shown in Table 1. Ta.

Reference Example 5 in Table 1 shows the amount of wear after evaluating Ag-10,3Ni in combination under the above conditions.

The numerical value shows the average value of two switches (there are 6 contact pairs because 3 phases are used). In addition, as shown in Examples 1 to 7, when 8nO2 or In2O3t is in the range of about 2 to about 15 parts, the total consumption is low, and the consumption on both the fixed and movable sides is close to each other, which is the desired consumption. It shows the situation. 5
n021B and In203t are less than 2 inches (Reference Examples 1 to 3)
), the wear amount of one or both of the fixed and movable parts is as shown in Example 1.
It is significantly larger than ~7. Further, Ag-10,3Ni (Reference Example-5), Ag-8nO2-In20. Examples 1 to 7 exhibit better wear characteristics than the other samples (Reference Example 6). In the surface layer of each test piece contact opened and closed under the above-mentioned current-carrying conditions, a phenomenon was observed in which the properties of both contacts were transferred to each other's poles with a fairly rapid number of openings and closings. For example, the Sn and In of the opposing movable contacts were transferred to the Ag-10,3Ni contact surface used in Example 6, and when strength was compared using an X-ray microanalyzer, it was found that the Ag-10,3Ni side also had Ag-
The surface layer on the 8n02-In205 side is also almost the same. Regarding Ni, when the contact surfaces were similarly compared, it was found that almost the same amount of Ni was present in the surface layer.

On the other hand, Ag-10,3Ni contact 10 used in Reference Example-1
- When Sn was similarly measured at the point, although transfer was observed, it was found that it was present in a significantly smaller amount than on the contact surface on the Ag-1,65n02 side.
It can be inferred that there is a difference in the transfer phenomenon compared to the above example.

In the process of repeating the cycle of evaporation or sublimation of the oxide dispersed in Ag by the arc → dissociation (release of oxygen) → reoxidation → adhesion, the equivalent amount of oxide in the contact, or the transferred oxide and Ni It is thought that the size of the particles influences the arc extinguishing effect and the smoothing effect on the contact surface, but the details of the mechanism of this unexpected effect are unknown.

The above effect is similar to that of other oxides CdO (Example-11) ZnO
(Example-12), 5b203 (Example-13) are also shown in the same way, and Ag-Ca2 (Reference Example 7), Ag
-ZnO2 (Table Example-8) and Ag-8b203 (Reference Example-9) show more preferable consumption conditions. Even if part or all of Nl (Example-14) is replaced by NiO, the effect can be expected to remain the same.

11- Note that in the above embodiment, an Ag-Ni type contact is set as the fixed side contact, but the opposite may be used.

That is, it is preferable to set the Ag-oxide type on the side where the switch is subject to a lot of wear and tear, which is affected by the structure of the switch, the heat capacity of the conductive part, the switching speed, opening and contact force, etc.

As for Example 10, since it contains a lot of Ni and the workability by sewage is inferior to other samples, a test piece was prepared by repeating sewage and heat treatment on a contact point of a predetermined size five times. Also, Examples 11 to 13, Reference Examples 7 to 9
About 0.01 to 0.1 wt of Bi was added to the Ag-oxide samples subjected to the treatment to increase the efficiency of internal oxidation treatment.

It was created by adding Ni, In+Sn, etc.

As explained above, according to the current switch of the present invention, an Ag-oxide type contact is placed on the pole with the most wear and tear, which appears to be either movable or fixed depending on the design conditions of the switch, and opposite to this. By arranging Ag-Ni or Ag-Ni0 type contacts on the poles, the contact characteristics can be improved without the need for special equipment, resulting in excellent productivity and extremely industrial value.

〔Effect of the invention〕

As described in detail above, the present invention provides that at least the contact surface of one of the opposing poles of the electrical contact in a current switch is made of an Ag-oxide based material, and that the electrical contact of the other pole is made of an Ag-oxide based material. Forming at least the contact surface with an Ag-Ni based material,
By taking advantage of the features of these materials, wear resistance and stable contact characteristics of the contacts can be obtained. Moreover, since this material can be used as a contact material, it will not be a hindrance to miniaturization, and it will improve performance and extend the lifespan. It is possible to provide a current switch whose service life can be extended.

[Brief explanation of drawings]

The figure is a sectional view showing a configuration example of a current switch according to the present invention. 1... Movable base metal, 2... Movable rod, 3... Contact spring, 5h, 5b... Conductive piece, 6m, 6b... Movable contact, Ia, 7b... Fixed contact, 8 ... Contact leaf spring, 9 ... Arc-extinguishing grid, 10 ... Excitation coil, 1
2*. j2b...iron core. Applicant's agent Patent attorney Takehiko Suzue 15-

Claims (3)

[Claims] (1) At least the contact surface of the electrical contact on one opposing pole is made of an Ag-oxide based material, and at least the contact surface of the electrical contact on the other pole is made of an Ag-Ni based material. current switch. (2) Ag-oxide material contains Cd as its oxide.
. The current switch according to claim 1, characterized in that it contains 2 to 15 oxides of at least one of Zn, Sn, In, and Sb. (3) The current switch according to claim 1, wherein the Ag-Ni material contains 5% by weight or more of Ni.