JPH03138829A - Sealed contact device - Google Patents

Abstract

PURPOSE:To prevent breakage such as cracks on a barrel section and improve reliability by arranging a thermal shock-resistant insulating plate on the inner wall of the barrel section of a seal container, blocking the contact between the barrel section of the seal container and an arc, and absorbing the arc heat with the thermal shock-resistant insulating plate. CONSTITUTION:A thermal shock-resistant insulating plate 16 is arranged in contact with the inner wall of a barrel section 2 to surround a fixed electrode 6 and a movable electrode 10 in an angle frame shape as a blocking means to block the contact between an arc generated when a fixed contact 6a and a movable contact 10a are separated and the barrel section 2 and protect the barrel section 2 from the thermal shock of the arc in a sealed contact device 1. The thermal shock-resistant insulating plate 16 which is the blocking means to block the contact between the arc generated when contacts are separated and the barrel section 2 of a seal container 5 is arranged on the inner wall of the barrel section 2 of the seal container 5, and the seal container 5 is protected from the thermal shock by the arc. The breakage of the seal container 5 due to the arc is prevented, reliability is improved, and a long life is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a sealed contact device suitable for use in electromagnetic switches and the like, and more particularly to a sealed contact device with improved arc resistance.

In conventional technology contact devices, due to the arc heat generated when cutting off large currents, especially DC current, the metal of the contacts and the electrode members connected to the contacts evaporates and scatters, contaminating the inside of the contact device and reducing the insulation properties and lifespan. There is a problem of letting it happen.

To solve this problem, a fixed contact and a movable contact are brought into contact with and separated from each other in a closed container filled with an insulating gas such as hydrogen (H2) at high pressure, and permanent magnet pieces are placed facing each other outside the container to insulate the contact. A sealed contact device has been proposed in which the arc is quickly extinguished by the cooling ability of the gas and the blowing effect of the magnetic field of the permanent magnet.

FIG. 10 is a cross-sectional view showing the structure of a sealed contact device 31 according to the prior art. The sealed contact device 31 includes a body portion 32 made of an electrically insulating material such as ceramics.
and metal end plates 33 and 34 that hermetically cover both upper and lower ends of the body 32, and the body 32 and the end plates 33 and 34 form a sealed container 35.

A fixed electrode 36 having a fixed contact 36a fixed to its tip is fitted and fixed on the inner surface of the lower end plate 34 on the side of the sealed container 35,
A trachea 37 is connected to the lower part, and an insulating gas is supplied to the sealed container 3.
The hermetic space 35a in the air-tight space 35a is sealed with high pressure of, for example, 3 atmospheres. The end of the trachea 37 forms a connection terminal to which a conductor (not shown) is connected. An insulating base 38 made of an electrically insulating material such as ceramics is disposed inscribed in the lower end plate 34 and the body 32 .

An upper insulating plate 39 made of the same material as the insulating base 38 is provided on the inner surface of the upper end plate 33 on the sealed container 35 side.
It is attached to 3. A movable contact 40a is fixed to one end of each of the insertion holes 33a and 39a formed to communicate between the end plate 33 and the upper insulating plate 39, and a movable electrode having a connecting terminal 40c formed at the other end. 40 metal movable shafts 40b are inserted.

A cylindrical body 41 into which the movable shaft 40b is loosely inserted is disposed at the outer upper part of the upper end plate 33. Inside the cylinder 41,
An accordion-shaped bellows 42 is arranged to surround the movable shaft 40b, and one end thereof is connected to the movable contact 40a of the movable shaft 40b.
The collar member 40d provided on the side has a cylindrical body 41 at the other end.
and the bellows pressing plate 41a, and the inside of the cylinder 41 is airtightly sealed at the same pressure as the inside of the sealed container 35.

A stopper 41b connected to the cylindrical body 41 is arranged at the top of the movable electrode 40, and restricts the amount of displacement of the movable electrode 40 in the direction opposite to the direction of arrow a when the movable contact 40a is separated. Furthermore, a pair of permanent magnet pieces (not shown) for blowing out the arc are disposed facing each other on the outer periphery of the body 32, and a magnetic field is generated from the back surface to the front surface at right angles to the plane of the drawing.

When the movable shaft 40b is pressed in the direction of arrow a by a drive means (not shown), the movable contact 40a comes into contact with the fixed contact 36a, and conduction occurs between the contacts. When the pressing force is removed, the movable shaft 40b is displaced upward by the restoring force of the bellows 42 due to the pressure difference between the inside and outside of the sealed container 35, and the fixed contact 36a and the movable contact 40a are separated, and the circuit is interrupted. Ru.

The permanent magnet piece moves the arc 43 generated between the fixed contact 36a and the movable contact 40a as shown by the arrow d by the Lorentz force caused by the current i and the magnetic field. The arc is quickly extinguished by the magnetic blowing effect and the cooling ability of the insulating gas, and the circuit is cut off.

Problems to be Solved by the Invention However, in the above-described sealed contact device 31, the temperature of the arc 43 generated when, for example, a heavy electric power load is interrupted reaches 10,000° C., and its duration is quite long. Such a high-temperature arc 43 acts as a large thermal shock on the body 32, causing cracks in the body 32, resulting in problems such as loss of airtightness and leakage of insulating gas. Therefore, there has been a desire for a sealed contact device that solves the above-mentioned problems and has improved arc resistance.

An object of the present invention is to provide a sealed contact device that can prevent damage to a sealed container due to arc, improve reliability, and extend life.

Means for Solving the Problems The present invention provides a sealed container in which both ends of a container body formed of an insulating material are covered with metal end plates, and an insulating gas is sealed at high pressure, and a fixed contact is installed at the tip. A fixed electrode and a movable electrode each having a fixed electrode and a movable contact are arranged facing each other, and the contact operation is realized by conducting/breaking the circuit by contact/separation of the contacts, and also eliminates the arc generated when the contact separates. In a sealed contact device that extinguishes an arc by cooling with the insulating gas and a magnetic blowing action of a magnet provided surrounding the sealed container, the thermal shock of the arc is removed by contacting the inner wall of the body of the sealed container. This is a sealed contact device characterized in that a blocking means is disposed to prevent this.

Function: The sealed contact device according to the present invention includes a heat-resistant insulating plate, which serves as a blocking means for preventing contact between the arc generated when the contact separates and the body of the sealed container, on the inner wall of the body of the sealed container, The sealed container is protected from thermal shock caused by the arc.

Embodiment FIG. 1 is a sectional view showing the structure of a sealed contact device 1 according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the section line 1--2 in FIG. The sealed contact device 1 includes a body 2 made of an electrically insulating material such as ceramics mainly containing alumina, and metal end plates 3.4 that hermetically cover both upper and lower ends of the body 2. A sealed container 5 is formed by the body 2 and the end plates 3 and 4, and a thermal shock-resistant insulating plate 16 is provided on the inner wall of the body 2 as a blocking means for preventing thermal shock of the arc, as will be described later. is located.

A fixed contact 6 is provided at the tip inside the sealed container 5 of the lower end plate 4.
A fixed electrode 6 to which a is fixed is fitted and fixed, a trachea 7 is connected to the lower part, and an insulating gas such as hydrogen (H2) is introduced into the airtight space 5a in the sealed container 5 at a high pressure of, for example, 3 atmospheres. Enclosed. The end of the trachea 7 forms a connection terminal to which the conducting wire 15a is connected. Inscribed in the lower end plate 4 and the body 2,
Insulating base 8 made of electrically insulating material such as ceramics
is located.

Inside the sealed container 5 of the upper end plate 3, an upper insulating plate 9 made of the same material as the insulating base 8 is attached to the upper end plate 3. A movable contact 1 is provided at one end of the insertion hole 3a9a bored so as to communicate between the end plate 3 and the upper insulating plate 9.
0a is fixed, and a metal movable shaft 10b of the movable electrode 10 having a connecting terminal 10c formed at the other end is inserted. A conductive wire 15b is drawn out from the connection terminal 10C.

A cylindrical body 11 into which the movable shaft 10b is loosely inserted is arranged at the outer upper part of the upper end plate 3. An accordion-shaped bellows 12 surrounding the movable shaft 10b is arranged inside the cylinder 11, and one end of the bellows 12 is connected to the movable contact 10 of the movable shaft 10b.
The collar member 10d provided on the a side, the other end is the cylinder 1
1 and a bellows pressing plate 11a, and the inside of the cylindrical body 11 is hermetically sealed at the same pressure as the inside of the sealed container 5.

A stopper llb that comes into contact with the cylinder 11 is arranged at the top of the movable shaft 10b to regulate the amount of displacement of the movable shaft 10b. Furthermore, a pair of permanent magnet pieces 13a and 13b for arc blowing out are held by a yoke 14 and placed facing each other on the outer periphery of the body 2, and a magnetic field B is generated from the back surface to the front surface at right angles to the plane of the paper in FIG. are doing.

The sealed contact device 1 according to this embodiment has an arc generated when the fixed contact 6a and the movable contact 10a are separated from each other and the body 2.
A thermal shock-resistant insulating plate 16 serves as a blocking means for preventing contact with the body 2 and protecting the body 2 from thermal shock of the arc.
The fixed electrode 6 and the movable electrode 10 are arranged so as to surround the fixed electrode 6 and the movable electrode 10 in a rectangular frame (bobbin) shape. Heat shock resistant insulation board 16
is made of, for example, a ceramic material mainly composed of zirconium oxide, and has a thickness of, for example, 1 mm.

When the movable shaft 10b is pressed in the direction of arrow A by a drive means (not shown), the movable contact 10a comes into contact with the fixed contact 6a, and conduction occurs between the contacts. When the pressing force is removed, the movable shaft 10b is displaced upward due to the restoring force of the bellows 12 due to the pressure difference between the inside and outside of the sealed container 5, and the fixed contact 6a and the movable contact 1
0a is separated and the circuit is cut off.

FIG. 3 is a sectional view for explaining the operation of this embodiment. In FIG. 3, parts common to FIGS. 1 and 2 are given the same reference numerals. When the pressing force is removed, the movable electrode 10 is restored and displaced in the direction opposite to the arrow A direction, and is movable. The arc 17 that occurs when the contact 10a separates from the fixed contact 6a and the circuit is interrupted is due to the action of the Lorentz force caused by the current I and the magnetic field B, and as the distance between the contacts 6a and 10a increases, the arc 17 becomes like an arrow. It moves in the direction shown (to the left in FIG. 3), ie towards the inner wall of the body 2 as indicated by reference numeral 17a. Although the duration of the arc 17 depends on the weight and nature of the interrupted load, it is, for example, 1/1000 second, and reaches the thermal shock resistant insulating plate 16 and exposes its surface to high temperature. This prevents direct contact between the arc 17 and the body 2.

The thermal shock-resistant insulating plate 16 used in this embodiment is made of ceramic mainly composed of zirconium oxide, and its melting point is around 1500°C, which is much lower than the arc temperature of 10000°C. , by being exposed to the arc 17, the surface in particular melts instantaneously,
It behaves to absorb the thermal energy of the arc 17,
In other words, it works to alleviate the thermal shock of the arc 17,
Once the arc 17 is extinguished, it solidifies immediately. therefore,
Combined with preventing contact between the body 2 and the arc 17, damage such as cracks to the body 2 due to thermal shock is prevented, airtightness is maintained, and the life of the device is extended and reliability is improved.

FIG. 4 is a sectional view showing an i-structure of a sealed contact device 21 according to another embodiment of the present invention, and FIG.
FIG. This embodiment is similar to the previous embodiment and corresponding parts are provided with the same reference numerals. What should be noted in this embodiment is that a groove 16a is provided on the outer peripheral surface of the thermal shock-resistant insulating plate 16. The space formed by this groove 16a is naturally filled with an insulating gas such as hydrogen sealed in the sealed container 5.

FIG. 6 is a sectional view for explaining the operation of this embodiment. The arc 17 that occurs when the pressing force of the movable shaft 10b is removed, the movable electrode 10 undergoes a restoring displacement, and the movable contact 10a separates from the fixed contact 6a is caused by the action of the Lorentz force caused by the current I and the magnetic field B. As the contacts 6a and 10a are separated, they move in the direction indicated by the arrow mark and reach the thermal shock-resistant insulating plate 16, the surface of which is exposed to the high temperature of the arc 17. However, as described above, in addition to the thermal shock resistance of the thermal shock resistant insulating board 16, the recess? 1116
An insulating gas with high cooling ability is interposed in the body part 2.
Since direct contact with the arc 17 is prevented, damage such as cracks to the body 2 is reliably prevented, and the life span and reliability of the device are further improved.

FIG. 7 shows a sealed contact device 22 of still another embodiment of the present invention.
FIG. 8 is a cross-sectional view taken along the section line ■--■ in FIG. 7. Similar to the previous embodiment,
Corresponding parts are given the same reference numerals.What should be noted in this embodiment is that the surface of the thermal shock-resistant insulating plate 16 disposed on the inner wall of the body 2 of the sealed container 5 is made of tungsten, a metal with a high melting point. The plural rows of tungsten protrusions 16b thus formed are arranged in a striped pattern.

The thermal shock-resistant insulating plate 16 used in this embodiment is made of, for example, a ceramic material mainly composed of alumina. This is because of the bondability with tungsten, which is the material of the protrusion 16b. The formation of the tungsten protrusions 16b on the thermal shock-resistant insulating plate 16 is achieved, for example, by applying tungsten paste in stripes on the surface of the ceramic material mainly composed of alumina, and then firing it at a predetermined temperature. The tungsten protrusion 16b has, for example, a prismatic shape with a cross section of 1 mm square.

FIG. 9 is a sectional view for explaining the operation of this embodiment. The arc 17 generated when the fixed contact 6a and the movable contact 10a are separated is the permanent magnet piece 13a.

Due to the Lorentz force caused by the magnetic field B and the current 13b, the thermal shock insulating plate 16 is exposed to the high temperature arc 17, but the thermal shock insulating plate 16 contact with the arc 17 is prevented. Moreover, the arc 17 blown onto the thermal shock-resistant insulating plate 16 is divided by the tungsten protrusions 16b provided on the surface thereof, as indicated by reference numeral 17a. Therefore, the arc 17 is rapidly extinguished,
Not only is the interrupting property improved, but the arc 17 is more reliably protected from thermal shock.

Effects of the Invention As described above, according to the present invention, a thermal shock-resistant insulating plate is arranged on the inner wall of the body of the sealed container to prevent contact between the body of the sealed container and the arc, and to reduce arc heat. Since the shock is absorbed by the insulating plate, damage such as cracks to the sealed container, especially the body, caused by the thermal shock of the arc is protected, resulting in a sealed contact device with significantly improved reliability and a long service life. With the realization of this system, its effects will be significant.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the structure of a sealed contact device 1 according to an embodiment of the present invention, Fig. 2 is a sectional view taken from the section line ■-n in Fig. 1, and Fig. 3 is a sectional view of the sealed contact device 1. A sectional view for explaining the operation of the device 1, FIG. 4 shows a sealed contact device 2 according to another embodiment of the present invention.
A sectional view showing the structure of No. 1, FIG. 5 is taken along the section line V- in FIG. 4.
6 is a sectional view for explaining the operation of the sealed contact device 21, and FIG. 7 is a sectional view showing the structure of a sealed contact device 22 according to still another embodiment of the present invention. , FIG. 8 is a sectional view taken along the cutting plane line ■-■ in FIG. 7, FIG. 9 is a sectional view for explaining the operation of the sealed contact device 22, and FIG. 3 is a cross-sectional view showing the structure of a contact device 31. FIG. 1.21.22...Sealing contact assembly r, 2...Body part, 5
... Sealed container, 6... Fixed electrode, 6a... Fixed contact, 10... Movable electrode, 10a... Movable contact, 12
...Bellows, 13a, 13b...Permanent magnet piece, 1
6... Heat shock resistant insulating plate, 16a... Concave groove, 16b.
...Tungsten protrusion, 17...Arc

Claims (1)

[Scope of Claims] A fixed contact and a movable contact are located at the tip of a sealed container in which both ends of a container body formed of an insulating material are covered with metal end plates and insulating gas is sealed at high pressure. A fixed electrode and a movable electrode, which are fixed to each other, are placed opposite each other, and the circuit is made conductive/broken by contact/separation of the contacts to realize contact operation, and the arc generated when the contacts separate is cooled by the insulating gas. and a sealed contact device that extinguishes an arc by the magnetic blowing action of a magnet provided surrounding the sealed container, the contact device being in contact with the inner wall of the body of the sealed container to prevent thermal shock of the arc. A sealed contact device characterized in that a blocking means is arranged.