JPH0375278A - Method for partially bonding porcelain to metal - Google Patents

Abstract

PURPOSE:To achieve the good bonding of a porcelain to a metal due to homogeneous heating by bringing a metal into contact with an intermediate thermal medium comprising a conductive material and subsequently heating the thermal medium with a high frequency induction heater to melt a glassy bonding agent mediated between the porcelain and the metal. CONSTITUTION:A metal plate 1 whose bonding surface is coated with a glassy bonding agent 2 is placed on the end surface of a lightning-conducting element receiver 3 and an intermediate thermal medium 4 is loaded on the metal plate 1. A press bar 8 is inserted into the hole 6 of the thermal medium 4 to allow to contact with the metal plate 1, and the metal plate 1 is pressed with the press bar 8 at a constant pressure. An electric current is applied to a high frequency conductive coil disposed at a place spaced from the upper, outer periphery of the thermal medium 4 at a prescribed interval to heat the thermal medium 4 and further heat the metal plate 1 with the conduction of heat from the thermal medium 4, whereby the heterogeneous state of heat distribution in the thermal medium is relaxed even when the coil itself produces the heat heterogeneously and the metal plate 1 and the glassy bonding agent 2 coated thereon can be homogeneously heated and melted.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for partially joining porcelain and metal, which is used, for example, when glass joining a metal plate to a porcelain insulator.

(Prior Art) For example, in the manufacturing process of a lightning arrester insulator, after a lightning arrester is housed in a lightning arrester housing, it is necessary to seal the end face of the lightning arrester with a metal plate serving as an electrode.

For this purpose, conventionally, as shown in FIG.
A metal high-frequency induction heating coil 04) is set at a certain distance, and by energizing this coil, the metal plate 02
1 was heated and the vitreous bonding agent 00 was melted by the heat to perform bonding.

However, in such a conventional joining method, the metal plate 021 is thin and has a small heat capacity, and the high-frequency induction heating coil 04) has a property that the temperature at its root becomes high. There was a drawback that +121 was unevenly heated, resulting in non-uniform bonding. In addition, in the conventional bonding method, when the power to the high-frequency induction heating coil (b) is stopped, the metal plate 02) rapidly cools down and pulls the vitreous bonding agent CI+) due to thermal contraction, which causes the vitreous bonding. There was a drawback that fine racks were formed in the agent (of), reducing the long-term reliability of the joint. Further, in the conventional method, it is not easy to accurately set the high-frequency induction heating coil (b) at a position slightly apart from the metal plate 021, and there is also a problem that workability is poor.

(Problem H to be solved by the invention) The present invention solves the above-mentioned conventional drawbacks, enables good bonding by uniform heating without uneven heat, and prevents cracks from occurring in the glassy bonding agent. This method was developed to provide a method for partially joining porcelain and metal, which is easy to work with and has good joining workability.

(Means for Solving the Problems) The present invention for solving the above problems uses an intermediate heat medium made of carbon or other conductive material when bonding porcelain and metal using a glass bonding agent. It is characterized by indirectly heating the metal by bringing it into contact with the metal and subjecting the intermediate heat medium to high-frequency induction heating, thereby melting and bonding the vitreous bonding agent interposed between the porcelain and the metal. be.

(Example) The present invention will be described in more detail below with reference to FIG.

In the figure, (1) is a metal plate whose joint surface is coated with a vitreous bonding agent (2), and (3) is a lightning arrester housing part formed in a porcelain insulator body. As for (1), a Kovar plate with a thickness of about 0.5 mm, which has a small difference in thermal expansion from porcelain, is used, and a vitreous bonding agent (2
) is said to have a thickness of about 0.1 to 0.4 mm. Further, the end face of the lightning arrester housing portion (3) is chamfered into a tapered shape, and the peripheral edge of the metal plate (1) is also chamfered into a tapered shape in accordance with this.

(4) is an intermediate heat medium made of carbon, conductive ceramics, or other conductive material, which is unique to the present invention. This intermediate heat medium (4) is required to have heat resistance as well as conductivity, and is also required to have a large heat capacity. The lower end of the intermediate heat medium (4) is tapered to match the shape of the peripheral edge of the metal plate (1), but there is a slight relief part (5) in the part corresponding to the end surface of the metal plate (1).
) is formed. Further, a hole (6) for pressing the metal Fi (1) with, for example, a presser foot (8) is formed in the center of the intermediate heat medium (4).

In order to join the metal plate (1) to the porcelain lightning arrester storage part (3) by the joining method of the present invention, first, the metal plate (1) whose joint surface is coated with the glass bonding agent (2) is attached to the lightning arrester. Place it on the end face of the element storage part (3), then place the intermediate heat medium (4) on the metal plate (1), and insert the presser foot (8) through the hole (6) of the intermediate heat medium (4). It comes into contact with the metal plate (1) and is pressed against the metal plate (1) with constant pressure by the presser foot (8). Then, when electricity is applied to the high frequency induction coil (7) installed at a predetermined gap on the upper outer periphery of the intermediate heat medium (4), the intermediate heat medium (4) is heated by high frequency induction, and further this intermediate heat medium (4) The metal Fi(1) is heated by heat conduction from. Therefore, even if the high-frequency induction coil (7) itself generates uneven heat, the intermediate heating medium (4) will alleviate the temperature distribution and unevenness of the cloth, and the metal plate (1) and the glass bonding agent applied thereto will (2) can be uniformly heated and melted. When the vitreous bonding agent (2) is melted in this way and the power is turned off, the intermediate heat medium (4) with a large heat capacity can be heated and melted uniformly.
) is kept in close contact with the metal plate (1) and its temperature is gradually lowered, and at the same time, the vitreous bonding agent (2) is also gradually cooled and solidified, completing the bonding.

In this way, in the present invention, the intermediate heat medium (4) can be brought into close contact with the metal plate (1), so that the workability of joining can be improved compared to the conventional method. Furthermore, if the intermediate heat medium (4) is provided with a relief part (5) as in the embodiment, the melted vitreous bonding agent (2) can be
Even if glass bulges on the upper end surface of 1(1), the glass does not adhere to the intermediate heat medium (4), and a preferable bonding can be performed.

Figure 2 shows the bonding method of the present invention and a third method that does not use an intermediate heat medium.
In the conventional bonding method shown by the 0 dotted line, which shows the temperature change of the metal plate (1) in the conventional bonding method shown in the figure, if the power supply is cut off 13 minutes after the start of energization, the metal plate (1)
) temperature decreases rapidly, from approximately 500°C to 20°C in 6 minutes.
Lower the temperature to 0℃. On the other hand, in the bonding method of the present invention shown by the solid line, approximately soo
It can be seen that the temperature of the metal plate (1) decreases slowly from 'c to 200''C.Therefore, according to the joining method of the present invention, the vitreous material melted together with the metal plate (1) Since the bonding agent (2) can be slowly cooled, there is no risk of producing cracks that can cause cracks in the vitreous bonding agent (2), and therefore, the long-term reliability of the joint can be improved.

Although the above explanation has focused on the manufacturing process of lightning arrester insulators, the present invention is not limited thereto, and it goes without saying that the present invention can be widely applied to joining metal and porcelain by high-frequency induction heating. There is no such thing.

(Effects of the Invention) As explained above, according to the present invention, since metals are heated via an intermediate heat medium made of a conductive material with a large heat capacity, uniform bonding can be performed without uneven heat. .

Further, according to the present invention, since the intermediate heat medium having a large heat capacity is heated while being brought into close contact with the metal, it is possible to prevent a rapid temperature drop even after the electricity is turned off, which causes clarification and rust in the glass bonding agent. Moreover, in the present invention, the intermediate heat medium only needs to be brought into close contact with the metal, so that the workability of joining can be improved.

Therefore, the present invention greatly contributes to the development of industry as a method for partially joining porcelain and metal, which eliminates the problems of the conventional method.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view explaining the bonding method of the present invention, Fig. 2 is a graph showing temperature changes of metal plates in the bonding method of the present invention and the conventional bonding method, and Fig. 3 is a graph explaining the conventional bonding method. FIG. (1): Metal plate, (2) Glass bonding agent, (3): Porcelain lightning arrester housing, (4): Intermediate heat medium, (7):
High frequency induction coil, (8): Presser bar.

Claims (1)

[Claims] When bonding porcelain and metal using a glass bonding agent, an intermediate heat medium made of carbon or other conductive material is brought into contact with the metal, and the metal is indirectly heated by high-frequency induction heating of this intermediate heat medium. A method for partially joining porcelain and metal, characterized by melting and joining a vitreous bonding agent interposed between the porcelain and metal.