JPS6364017B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to improvements in combination electrical contacts. Recently, with the development of electrical and electronic technology, various electrical
As electronic devices have become smaller, breakers, magnetic switches, etc. have also become smaller. However, as breakers, magnetic switches, etc. become smaller, the contact gap becomes narrower and the ability to block arc discharge becomes worse. In other words, the problem arises that the arc cannot be cut. There is also the problem that the contact force and separation force of the electrical contacts are reduced, making it easier for welding to occur. For this reason, there is a demand for a combination electrical contact with good arc-blocking properties and excellent welding resistance, and various combination electrical contacts have been developed, but so far none has been satisfactory. Traditionally, combination electrical contacts have been made of silver-oxide contacts in which metal oxides are dispersed in silver, or silver-high melting point contacts in which metals with high contact points are dispersed in silver. A combination electrical contact in which contacts made of silver-nickel alloy face each other has superior welding resistance than a combination electrical contact in which contacts made of a silver-nickel alloy face each other, but the tin oxide in the silver-tin oxide prevents the contact from closing. Since tin oxide itself is stable up to around 2000℃, smooth unevenness is formed on the contact surface, and the contact gap becomes narrower, resulting in poor arc blocking performance. In extreme cases, a situation may arise in which the arc cannot be interrupted. Furthermore, in the case of a combination electrical contact in which contacts made of a silver-nickel alloy are opposed to each other, especially when the concentration of nickel is increased, the contact surface is very stable and has very few irregularities, and has good arc blocking properties. However, because the surface temperature rises rapidly, the underlying silver tends to melt and cause welding, posing a problem in welding resistance. Another disadvantage is that initial welding may occur due to the characteristics of the silver-nickel alloy. In this way, conventional combination electrical contacts use the same electrical contact material for the opposing fixed and movable contacts, so they have good welding resistance but poor arc blocking properties, and conversely, arc blocking properties are poor. Although it was good, there were problems such as poor initial welding resistance. Therefore, the inventors of the present invention have conducted intensive research to develop a combination electrical contact that has good arc interrupting properties and excellent welding resistance even in miniaturized breakers, magnetic switches, etc. It has been found that by using different contact materials for the contact and the movable contact, welding resistance and arc blocking performance can be improved and initial welding can be eliminated. The present invention has been made focusing on this point, and uses a silver-tin oxide contact and a high-concentration silver-nickel contact as a combination electrical contact that can reliably improve welding resistance and arc blocking performance and eliminate variations. It is an object of the present invention to provide a combination electrical contact formed by opposing alloy contacts. The combination electrical contact according to the present invention comprises 2% to 15% by weight of tin and 0.01% to 1% by weight of at least one of lead, germanium, bismuth, and nickel in the opposing contacts, and the balance is silver. Silver-tin oxide contacts and nickel 20% by weight
The invention is characterized in that it uses a contact made of a silver-nickel alloy consisting of more than 50% by weight or less and the balance being silver. The reason for limiting the materials of the opposing contacts in the combination electrical contact of the present invention as described above is to take advantage of the excellent welding resistance of the silver-tin oxide system, and also to take advantage of the excellent arc-blocking properties of the high-concentration silver-nickel alloy. Take advantage of your sexuality,
This synergistic effect is intended to eliminate the poor welding resistance or poor arc interrupting properties of conventional combined electrical contacts in which contacts made of the same material are placed opposite each other. The reason for limiting the content of silver-tin oxide to 2% to 15% by weight is that less than 2% by weight results in insufficient adhesion resistance, while more than 15% by weight causes no problem in adhesion resistance. This is because the amount of tin oxide that aggregates on the contact surface increases and the contact resistance increases. Also, the reason why lead, germanium, bismuth, and nickel are added is to make the oxides uniform and fine, but if it is less than 0.01% by weight, it has no effect, and if it exceeds 1% by weight, these oxides will form grain boundaries. This is because they aggregate and impede contact performance. The reason why the amount of nickel in the silver-nickel alloy was set to be more than 20% by weight and less than 50% by weight is that less than 20% by weight is not sufficient to eliminate the poor arc blocking properties of silver-tin oxide, and if it exceeds 50% by weight, the amount of nickel is This is because contact resistance increases significantly due to oxidation. Next, in order to clarify the effects of the combined electrical contact according to the present invention, specific embodiments and conventional examples thereof will be described. Example 1 A fixed contact of 5φmm consisting of silver-tin oxide-germanium oxide with a metal element composition of 7.5% by weight of tin, 0.5% by weight of germanium, and the balance being silver;
A 4 mm movable contact made of a silver-nickel alloy of 40% by weight nickel and the balance silver was made to face each other to form a combination electrical contact. Example 2 Component composition of metal elements: tin 10% by weight, lead
A combination electrical contact is made by opposing a 5φmm fixed contact made of silver-tin oxide-lead oxide with 0.7% by weight and the balance being silver and a 4φmm movable contact made of a silver-nickel alloy with 25% by weight of nickel and the balance being silver. Configured. Example 3 Component composition of metal elements: tin 10% by weight, lead
A combination electrical contact is made by arranging a 4φmm movable contact made of silver-tin oxide lead monoxide with 0.7% by weight and balance silver and a 5φmm fixed contact made of silver-nickel alloy with 25% by weight nickel and balance silver facing each other. Configured. Example 4 A 4φmm movable contact consisting of silver-tin oxide-bismuth oxide with the composition of the metal elements being 7.5% by weight of tin, 0.1% by weight of bismuth and the balance being silver, and a silver-nickel alloy having 25% by weight of nickel and the balance being silver. A combination electric contact was constructed by facing a fixed contact of 5φmm. Example 5 Component composition of metal elements: tin 5% by weight, lead
Silver - 0.2% by weight, 0.1% by weight of nickel and the balance silver
4φmm made of tin oxide, lead oxide, and nickel oxide
A movable contact and a fixed contact of 5 mm made of a silver-nickel alloy of 40% by weight of nickel and the balance of silver were made to face each other to form a combined electrical contact. Example 6 A fixed contact of 5φmm consisting of 12% by weight of tin, 0.4% by weight of germanium, 0.3% by weight of bismuth and the balance being silver - tin oxide - germanium oxide - bismuth oxide as a component composition of metal elements, 40% by weight of nickel and 4φ made of silver-nickel alloy with the balance being silver
A combination electric contact was constructed by facing the mm movable contact. Conventional example 1 A fixed contact of 5φmm consisting of silver-tin oxide with the metal element composition being 10% by weight tin and the balance being silver.
A combination electric contact was constructed by facing a 4φmm movable contact. Conventional Example 2 A fixed contact of 5 mm and a movable contact of 4 mm made of a silver-nickel alloy of 40% by weight of nickel and the balance silver were combined to form an electric contact. When each of these combinations of electrical contacts was subjected to a welding resistance test and the arc interruption time at interruption was measured under the following test conditions, the results shown in the table below were obtained. Welding resistance test (9 test points) Voltage: AC100V, 50Hz Current: 40A input, 10A steady state Opening/closing frequency: 20 times/min Load: Resistance load Contact force: 40g Peeling force: 40g Number of openings/closings: Until welding occurs Measurement conditions for arc duration at interruption Γ DC24V 3A Γ Contact gap before test 0.7 mm Γ Breaking speed 5 cm/sec

[Table] As is clear from the table above, the combination electrical contact of the present invention, in which a silver-tin oxide contact and a high-concentration silver-nickel alloy contact are opposed to each other, is said to have exceptionally good welding resistance. This combination electrical contact has excellent welding resistance equivalent to the conventional combination electrical contact that has silver-tin oxide contacts facing each other, and also has silver-nickel alloy contacts that have good arc blocking properties that face each other. It has excellent arc blocking properties. The silver-tin oxide contact in the present invention is made by an internal oxidation method, a powder metallurgy method, a combination of an internal oxidation method and a powder metallurgy method, etc., and the metal oxide is finely dispersed in the silver. If it's something, that's fine. As detailed above, the combination electrical contact of the present invention is
It has exceptional welding resistance and arc blocking properties, so when used in miniaturized breakers, magnetic switches, etc., it can suppress the occurrence of welding and ensure arc blocking. There is an effect.

Claims (1)

[Claims] 1 2 to 15% by weight of tin as a component composition of metal elements
and a contact point of silver-tin oxide-lead oxide-germanium oxide-bismuth oxide and nickel oxide, consisting of a total of 0.01 to 1% by weight of at least one of lead, germanium, bismuth, and nickel, and the balance being silver, and nickel 20% by weight. %, but not more than 50% by weight, and the balance is silver.