JPH0610591Y2 - Switch for high voltage - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an electric circuit switch using an insulating valve made of ceramic, which is manufactured by compressing and compressing a ceramic base powder and firing it. The present invention relates to a high load switch suitable for switching voltage and large current.

[Prior Art] The insulating cylinder 100 of FIG. 6 has a straight body portion 110 and a convex portion 120.
The angle formed by and is a right angle, and the corner 130 is substantially angular.

The insulating cylinder 100 of FIG. 7 has a straight body portion 110 and a convex portion 120.
The angle θ formed by and is an obtuse angle, and the corner 130 is angular (Japanese Patent Laid-Open No. 64-21838).

[Problems to be Solved by the Invention] The insulating cylinder 100 is usually manufactured by a rubber press.

At the time of compression under pressure, the convex portion 120 transmits the compressive force to the straight body portion 11.
It tends to be weaker than 0, especially at corner 130
It is 0% reduction (when the radius of curvature is 1 mm in Fig. 6 product) to 40% reduction (when θ = 110 ° in Fig. 7 product).

(Problem of FIG. 6 product) There is a factor that stress concentration is likely to occur in the corner 130 after firing and the insulation strength is weakened when a high voltage is applied.

If the rubber press molding pressure is low, firing failure occurs due to the difference in shrinkage during firing.

(Problem of the product shown in FIG. 7) The compression force at the corner 130 cannot be improved unless the angle θ is significantly increased (110 ° or more). For this reason,
It is difficult to braze the arc shield to the convex portion 120.
Moreover, if the wall thickness of the convex portion 120 is increased, the convex portion 120 becomes large and the weight increases.

The stress concentration at the corner 130 still remains.

An object of the present invention is to provide a high-voltage switch which is less likely to cause stress concentration at corners, has excellent insulation strength when a high voltage is applied, and can reduce firing defects during firing.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides an inwardly projecting convex portion at an intermediate portion of the inner peripheral wall, and further comprises the convex portion and the inner peripheral wall. The angle formed is an insulating cylinder made of ceramic whose angle is θ,
An end plate attached by closing one end side of the insulating cylinder, a fixed electrode attached to the end plate and protruding into the insulating cylinder, an end plate attached by closing the other end side of the insulating cylinder, In a high-voltage switch equipped with a movable electrode that is attached to the end plate and forms a contact with the fixed electrode, an angle θ (°) of an angle formed by the convex portion and an inner peripheral wall and The relationship of the radius of curvature R (mm) is that the (θ) angle θ is 90 ° to 1
R = (-1/20) × θ + 15 / in the range of 30 °
2 and the minimum value of the radius of curvature R by the straight line of R = 1 in the range of the angle θ of 130 ° to 150 °,
(I) R = 5 when the angle θ is in the range of 90 ° to 110 °
And the maximum value of the radius of curvature R by the straight line of R = (-1/20) × θ + 21/2 in the range of the angle θ of 110 ° to 150 ° are adopted.

[Operation and Effect of Invention] The relationship between the angle θ (°) formed by the convex portion and the inner peripheral wall and the radius of curvature R (mm) of the angle is 90 ° to 130 °.
In the range of R = (− 1/20) × θ + 15/2, and the straight line of R = 1 in the range of the angle θ of 130 ° to 150 °, the minimum value of the radius of curvature R and the angle θ.
Of R = 5 in the range of 90 ° to 110 °, and R = (− in the range of the angle θ of 110 ° to 150 °.
1/20) × θ + 21/2 straight line radius of curvature R
Within the maximum value of.

For this reason, even when the press molding pressure is relatively low, during compression compression molding of the ceramic base powder, the corner portion of the ceramic base powder is uniformly compressed like other parts, and when the ceramic base powder is fired, the compressed powder It is possible to make the heat shrinkage not much different from other parts. Therefore, firing unevenness is unlikely to occur, firing defects such as firing cracks can be reduced, and the dielectric breakdown strength when a high voltage is applied due to such factors is excellent.

In addition, since the corners are rounded, stress concentration is less likely to occur at the corners, which is advantageous for improving the dielectric breakdown strength when a high voltage is applied.

The reason for the numerical limitation is as follows.

The angle θ formed by the convex portion and the inner peripheral wall and the radius of curvature R of the angle
This is because if the relationship with the above is less than the above-mentioned minimum value, the above-mentioned effect is extremely small, and if it exceeds the above-mentioned maximum value, unnecessary shape of the convex portion and enlargement of the valve diameter are caused.

[Embodiment] Next, a first embodiment of the present invention will be described with reference to FIG. 1, FIG. 2, FIG. 4, FIG.

As shown in FIG. 1, the vacuum load switch A includes an insulating valve 1 and an end cover 2 attached by closing an end of the valve 1.
3, a fixed electrode 4 attached to the end cover 2 and protruding into the insulating valve 1, and a movable electrode 5 slidably arranged on the end cover 3. Moreover, a contact 6 is formed between the fixed electrode 4 and the movable electrode 5.

The insulation valve 1 is made of a ceramic fired body of 92% by weight alumina and has an inner diameter of 80 mm and a wall thickness of 5 mm (usually 4 mm to 6 m).
m), and has a substantially cylindrical shape with a length of 100 mm. Further, the insulating valve 1 includes a straight body portion 10 having a constant inner diameter and an inner peripheral wall 1.
In the middle of 1, there is a convex portion 12 (usually 3 mm to 5 mm) that is provided so as to project inwardly. The corner portion 13 (the angle θ formed by the inner peripheral wall 11 of the straight body portion 10 and the inner peripheral wall 11 of the straight body portion 10 is 90 °, the radius of curvature R) is shown in FIG. It has an arc of 3 mm to 5 mm. The radius of curvature of the corner portion 14 on the tip side of the convex portion 12 is 1 mm.

The insulation valve 1 is manufactured as follows.

Alumina powder (92% by weight) is rubber press molded. The molding pressure was 400 kg / cm ² in each of the examples (insulation valve No. 3 of Example 1 and insulation valve N of Example 2).
It is 800 kg / cm ^{2 at} 15 o'clock.

Expected to shrink, it is processed on a lathe to the prescribed dimensions shown in Table 1 and then fired in an air atmosphere at 1600 ° C.

Then, a glaze is applied to the surface, and the glaze is baked at 1300 ° C. to complete the process.

The end covers 2 and 3 are formed of a disk-shaped Kovar (Fe—Ni—Co) plate, and holes 21 and 32 for fixing the fixed electrode 4 and the guide 31 are formed in each central portion. Guide 31
Is provided so that the movable shaft 51 of the movable electrode 5 can easily slide.

The fixed electrode 4 has a rear end serving as a fixed shaft 41 fixed in the hole 21, and a front end serving as an annular electrode 42 protruding into the insulating valve 1.

The movable electrode 5 has a rear end serving as a movable shaft 51 that slides in the guide 31 and a front end that contacts the electrode 42.
Has become. The movable electrode 5 is the movable shaft 5 near the electrode 52.
The bellows-shaped metal bellows 53 provided between the end cover 1 and the end cover 3 enables the opening / closing operation in a vacuum holding state.
Further, the metal bellows 53 is surrounded by a bellows cover 54, and the electrodes 42 and 52 (contacts 43 and 55) are opened and closed when the current is opened and closed.
Prevents direct contact with metal vapor generated from.

The contact 6 uses a high melting point tungsten-based sintered alloy for the contacts 43, 55 with which the electrodes 42, 52 are brought into contact with each other, and has a structure that is difficult to weld by a generated vacuum arc. Further, an arc shield 61 is arranged so as to surround the contact 6. The arc shield 61 is provided by brazing 62 on the convex portion 12 of the insulation valve 1 in order to prevent the above-mentioned metal vapor from adhering to the inner wall of the insulation valve 1 and lowering the insulation. The arc-extinguishing action at the time of circuit interruption is performed by the high dielectric strength and fast electron diffusion action of the high vacuum.

The operation and effect of the vacuum load switch A according to the present invention is as follows.

(A) As shown in FIG. 4, the convex portion 12 of the insulation valve 1
And electrodes 71 and 72 are arranged on the outer wall side of the insulating valve 1 corresponding to the convex portion 12 (charge is concentrated on the corner portion 13), and a high voltage of 60 Hz and 40 kV is applied (high As shown in Table 1, none of the devised products (insulation valves No. 4, No. 5 and 6) c out of 1000 did not penetrate. Therefore, in the vacuum load switch A, stress concentration is unlikely to occur at the corner portion 13, and dielectric breakdown at the convex portion 12 of the insulating valve 1 is extremely unlikely to occur. Further, the molding failure during firing did not occur in the insulation valves No. 4, No. 5 and No. 6.

Conventional product (insulation valve No. 1, No. 2) and insulation valve N
Penetration by high voltage application test of o.3 is 1 each
It is 2, 1, and 0 out of 000. In addition, the molding defects during firing are 20 pieces, 5 pieces, and 2 pieces per 1000 pieces, respectively.

(A) In the vacuum load switch A, since the convex portion 12 of the portion of the arc shield 61 to be brazed 62 is flat, the arc shield 61 and the insulating valve 1 can be easily attached.

Next, a second embodiment of the present invention will be described with reference to FIGS.
Description will be made based on FIG. 5, FIG. 5, and Table 1.

The vacuum load switch B, as shown in FIG.
The angle θ formed by the inner peripheral wall 11 of the straight body portion 10 is 100 ° to 1
It is set to 50 °. The radius of curvature of the corner portion 13 of the insulating valve 1 is 1 mm to 5 mm, and the radius of curvature of the corner portion 14 is 1 mm, as shown in FIG.

The operation and effect of the vacuum load switch B of the present invention are as follows.

(C) As shown in Table 1, the vacuum load switch B did not cause any molding failure during firing even at a relatively low molding pressure (400 kg / cm ² ). In the high voltage application test described above, no penetration occurred in 1000 wires. Therefore, in the vacuum load switch B, the compression force between the corner portion 13 and other portions can be made uniform during pressure compression, and at the time of firing,
Baking failure is extremely unlikely to occur. In addition, since stress concentration is unlikely to occur at the corners 13, the insulation strength when a high voltage is applied is excellent.

(D) Since the angle θ formed by the convex portion 12 and the inner peripheral wall does not have to be significantly increased (the angle θ is about 100 ° and the radius of curvature is 2.5 mm to 5 mm), the weight of the convex portion 12 is large. It is possible to secure a predetermined wall thickness of the convex portion without significantly increasing.

(E) In the vacuum load switch B, the bending ratio of the convex portion 12 of the portion of the arc shield 61 to be brazed 62 can be made smaller than that of the conventional one, so that the arc shield 61 and the insulating valve 1 can be easily attached. is there.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment and a second embodiment of a vacuum load switch according to the present invention. FIG. 2 is an enlarged view of an essential part of the first embodiment, and FIG. 3 is an enlarged view of an essential part of the second embodiment. FIG. 4 is a graph showing a possible range of an angle θ formed by the convex portion and the inner peripheral wall and a radius of curvature R of the angle in the present invention. FIG. 5 is a sectional view showing a test method of a high voltage application test of the vacuum load switch in each example. FIG. 6 is a sectional view of a conventional vacuum load switch. FIG. 7 is a sectional view of a main part of a conventional vacuum load switch. In the figure, 1 ... Insulation valve (insulation cylinder), 2, 3 ... End cover (end plate), 4 ... Fixed electrode, 5 ... Movable electrode, 6 ... Contact point, 11 ... Inner peripheral wall, 12 ... ... Convex portion, 13 ... Corner (corner), θ ... Angle formed by the convex portion and the inner peripheral wall of the straight body portion (angle formed by the convex portion and inner peripheral wall), A, B ... Vacuum Load switch (switch for high voltage)

Claims (1)

[Scope of utility model registration request] 1. An insulating cylinder made of ceramic, wherein an inwardly projecting convex portion is provided around an intermediate portion of the inner peripheral wall, and an angle formed by the convex portion and the inner peripheral wall is an angle θ. An end plate attached by closing one end side of the insulating cylinder, a fixed electrode attached to the end plate and protruding into the insulating cylinder, and an end plate attached by closing the other end side of the insulating cylinder. And a movable electrode attached to the end plate and forming a contact between the fixed electrode and the fixed electrode, wherein an angle θ (°) of an angle formed by the convex portion and the inner peripheral wall, and The relationship of the radius of curvature R (mm) is (a) R = in the range of the angle θ of 90 ° to 130 °
(-1/20) × θ + 15/2 straight line, and the minimum value of the radius of curvature R by the straight line R = 1 in the range of the angle θ of 130 ° to 150 °, and (i) the angle θ of 90 ° to 110. R = 5 in the range of °
And a maximum value of the radius of curvature R by a straight line of R = (-1/20) × θ + 21/2 in the range of an angle θ of 110 ° to 150 °. Switch.