JP5202475B2 - Mold vacuum valve - Google Patents

Description

  The present invention relates to a molded vacuum valve in which a vacuum valve having a pair of contactable and separable contacts is molded with an insulating material such as an epoxy resin, and an insulating layer is formed on the outer periphery.

  Conventionally, in a vacuum valve molded with an epoxy resin, since the end of a sealing fitting constituting the vacuum valve has an acute angle and the electric field strength is increased, an electric field relaxation shield that covers this is known. (For example, refer to Patent Document 1).

  A mold vacuum valve of this type is shown in FIG. 5, and a fixed-side sealing metal fitting 2 and a movable-side sealing metal fitting 3 are sealed at both ends of a vacuum insulating container 1 made of cylindrical ceramics. A fixed-side energizing shaft 4 is fixed through the fixed-side sealing metal fitting 2, and a fixed-side contact 5 is fixed to the end. The movable contact 6 is fixed to the end of the movable energizing shaft 7 that movably penetrates the movable sealing fitting 3 so as to face the fixed contact 5.

  One end of a telescopic bellows 8 is sealed at an intermediate portion of the movable energizing shaft 7. The other end is sealed in the opening of the movable side sealing fitting 3. A cylindrical arc shield 9 provided so as to surround the contacts 5 and 6 is fixed to the inner surface of the vacuum insulating container 1.

  A hook-shaped fixed-side electric field relaxation shield 10 is fixed to the fixed-side sealing fitting 2 so as to cover the outer peripheral end portion thereof. The distal end portion of the fixed-side electric field relaxation shield 10 extends until it wraps with the end portion of the vacuum insulating container 1. In addition, a hook-like movable-side electric field relaxation shield 11 is fixed to the movable-side sealing metal fitting 3 so as to cover the outer peripheral end portion thereof. The distal end portion of the movable side electric field relaxation shield 11 also extends until it wraps with the end portion of the vacuum insulating container 1. The electric field relaxation shields 10 and 11 are generally made of a copper material having good workability.

  An insulating layer 12 formed by molding with an epoxy resin is provided on the outer periphery of the vacuum insulating container 1 and the electric field relaxation shields 10 and 11. On the outer periphery of the insulating layer 12, a ground layer 13 formed by applying a conductive paint is provided. The axial direction on the fixed side of the insulating layer 12 is a concave interface connecting portion 14, and the movable side is a convex interface connecting portion 15, which is connected to other electrical devices.

JP 2005-276472 A (page 4, FIG. 1)

  The above-described conventional mold vacuum valve has the following problems. The fixed-side electric field relaxation shield 10 and the movable-side electric field relaxation shield 11 can reduce the electric field at the ends of the fixed-side sealing metal fitting 2 and the movable-side sealing metal fitting 3. The electric field relaxation shields 10 and 11 expand in the radial direction, then bend approximately 90 degrees in the axial direction, and extend until the tip ends overlap with the vacuum insulating container 1. That is, the electric field relaxation shields 10 and 11 have an L-shaped cross section, and the portions extending in the axial direction are arranged coaxially with the vacuum insulating container 1.

  For this reason, the insulating layer 12 between the vacuum insulating container 1 and the portion where the electric field relaxation shields 10 and 11 extend in the axial direction has a rectangular cross section, and the inner periphery and the outer periphery are constrained. The vacuum insulating container 1, the electric field relaxation shields 10, 11 and the insulating layer 12 are all made of different materials and have different thermal expansion coefficients. For this reason, when a temperature change occurs during molding or the usage environment, stress is generated in the constrained insulating layer 12, and the insulating layer 12 may be peeled off from the vacuum insulating container 1 or the electric field relaxation shields 10 and 11. . In addition, cracks may occur in the insulating layer 12. Furthermore, if the electric field relaxation at the tips of the electric field relaxation shields 10 and 11 is insufficient, insulation deterioration occurs from this portion.

  For this reason, what improved the adhesive force of the electric field relaxation shields 10 and 11 and the insulating layer 12, suppressed peeling, etc., aimed at the electric field relaxation of the front-end | tip part, and the thing which can exhibit the outstanding insulation performance was desired. .

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a mold vacuum valve capable of improving the adhesion between the electric field relaxation shield and the insulating layer and reducing the electric field at the tip. .

  In order to achieve the above object, the mold vacuum valve of the present invention includes a cylindrical vacuum insulation container, a fixed-side sealing metal fitting and a movable-side sealing metal fitting sealed at both ends of the vacuum insulation container, A fixed-side energizing shaft that is fixed through the fixed-side sealing metal fitting, a fixed-side contact that is fixed to the fixed-side energizing shaft end, a movable-side contact that is in contact with and away from the fixed-side contact, and the movable-side contact. The movable-side energizing shaft that sticks and penetrates the movable-side sealing fitting in an airtight manner, the fixed-side electric field relaxation shield provided so as to cover the outer peripheral end of the fixed-side sealing fitting, and the movable A movable-side electric field relaxation shield provided so as to cover an outer peripheral end of the side sealing metal fitting, and an insulating layer formed by molding an insulating material on the outer periphery of the vacuum insulating container and the electric field relaxation shield, Each electric field relaxation shield is radial It is composed of an axial and distal ends extending radially portion and axially extending, than said radial portion and the axial portion, characterized in that finely the surface roughness of the tip.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesive force of an electric field relaxation shield and an insulating layer can be improved, and the electric field relaxation of an electric field relaxation shield front-end | tip part can be aimed at.

Sectional drawing which shows the structure of the mold vacuum valve which concerns on Example 1 of this invention. The principal part expanded sectional view which shows the structure of the electric field relaxation shield which concerns on Example 1 of this invention. The principal part expanded sectional view which shows the structure of the mold vacuum valve which concerns on Example 2 of this invention. The principal part expanded sectional view which shows the structure of the mold vacuum valve which concerns on Example 3 of this invention. Sectional drawing which shows the structure of the mold vacuum valve by a conventional method.

  The electric field relaxation shield provided on the sealing metal fitting is composed of a radial portion, an axial portion, and a tip portion, and the surface roughness of the tip portion is made finer than that of the axial portion. Embodiments according to the present invention will be described below with reference to the drawings.

  First, a mold vacuum valve according to Example 1 of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing a configuration of a mold vacuum valve according to Embodiment 1 of the present invention, and FIG. 2 is an enlarged cross-sectional view of a main part showing a configuration of an electric field relaxation shield according to Embodiment 1 of the present invention. In FIG. 1, the same components as those in the prior art are denoted by the same reference numerals.

  As shown in FIG. 1, a fixed-side sealing metal fitting 2 and a movable-side sealing metal fitting 3 are sealed at both end openings of a vacuum insulating container 1 made of cylindrical ceramics. A fixed-side energizing shaft 4 is fixed through the fixed-side sealing metal fitting 2, and a fixed-side contact 5 is fixed to the end. The movable contact 6 is fixed to the end of the movable energizing shaft 7 that movably penetrates the movable sealing fitting 3 so as to face the fixed contact 5.

  One end of a telescopic bellows 8 is sealed at an intermediate portion of the movable energizing shaft 7. The other end is sealed in the opening of the movable side sealing fitting 3. Thereby, the movable energizing shaft 7 can be moved in the axial direction while maintaining the vacuum in the vacuum insulating container 1. A cylindrical arc shield 9 provided so as to surround the contacts 5 and 6 is fixed to the inner surface of the vacuum insulating container 1.

  A hook-shaped fixed-side electric field relaxation shield 20 is fixed to the fixed-side sealing fitting 2 so as to cover the outer peripheral end portion thereof. The fixed-side electric field relaxation shield 20 includes a radial direction 20a spreading in the radial direction, an axial direction portion 20b connected to the radial direction portion 20a and bent in the axial direction, and a tip 20c having a spherical section connected to the axial direction portion 20b. It consists of and. The tip 20c extends until it wraps with the end of the vacuum insulating container 1. The diameter of the tip portion 20c is larger than the thickness of the axial portion 20b.

  Similarly to the fixed side, a hook-shaped movable-side electric field relaxation shield 21 that covers the outer peripheral end portion is also fixed to the movable-side sealing fitting 3. The movable-side electric field relaxation shield 21 also has a radial direction 21a spreading in the radial direction, an axial direction portion 21b connected to the radial direction portion 21a and bent in the axial direction, and a tip end portion 21c having a spherical section connected to the axial direction portion 21b. It consists of The distal end portion 21c also extends until it wraps with the end portion of the vacuum insulating container 1, and is spaced apart from the stationary distal end portion 20c while maintaining a predetermined insulation distance.

  An insulating layer 12 formed by molding with an epoxy resin is provided on the outer periphery of the vacuum insulating container 1 and the electric field relaxation shields 20 and 21. On the outer periphery of the insulating layer 12, a ground layer 13 formed by applying a conductive paint is provided. The axial direction on the fixed side of the insulating layer 12 is a concave interface connecting portion 14, and the movable side is a convex interface connecting portion 15, which is connected to other electrical devices.

  Here, as shown in FIG. 2, in the electric field relaxation shields 20 and 21, the radial direction portions 20a and 21a and the axial direction portions 20b and 21b are uneven, for example, by sandblasting. The tip portions 20c and 21c are equivalent to a mirror finish with a finer roughness than this. The surface roughness of the radial direction portions 20a, 21a, etc. is set to a size that absorbs the thermal expansion coefficient of the insulating layer 12.

For example, when the electric field relaxation shields 20 and 21 are made of copper, the coefficient of thermal expansion is 16 × 10 ⁻⁶ / ° C., which is smaller than the coefficient of thermal expansion of epoxy resin 20 × 10 ⁻⁶ / ° C. For this reason, the product of this difference multiplied by the temperature change is the stress applied to the epoxy resin. Accordingly, the surface roughness of the radial direction portions 20a, 21a, etc. is set to several tens of μm which is equal to or larger than the size obtained by multiplying the difference in thermal expansion coefficient, temperature change, and insulation thickness of several tens of millimeters in order to disperse this stress.

  Even if the material of the electric field relaxation shields 20 and 21 or the insulating layer 12 is changed and the coefficient of thermal expansion of the electric field relaxation shields 20 and 21 is larger than that of the insulating layer 12, the direction of the stress only changes from compression to tension. , Stress distribution can be performed. Moreover, the radial direction parts 20a and 21a and the axial direction parts 20b and 21b can add an anchor effect, and can improve adhesive force.

  The tip portions 20c and 21c are portions where the electric field strength is highest, and the surface roughness is set to several μm or less. In each of the uneven portions, the electric field strength increases when viewed microscopically, but when viewed from the entire tip portions 20c and 21c, the corona stabilizing action works, and as a result, the electric field can be relaxed. The surface roughness is fine, and the more unevenness per unit area, the easier the corona stabilization effect will work. The tip portions 20c and 21c are spherical in cross section, and this shape itself can reduce the electric field, but further electric field relaxation can be achieved by the corona stabilizing action.

  The surface of the vacuum insulating container 1 is also subjected to sand blasting with a surface roughness similar to that of the radial direction portions 20a, 21b, etc., at least on the portion facing the region from the axial direction portions 20b, 21b to the tip portions 20c, 21c. However, the adhesive force can be improved.

  According to the mold vacuum valve of Example 1 described above, the electric field relaxation shields 20 and 21 provided on the sealing fittings 2 and 3 are radially extended from the radial portions 20a and 21a, and the axial portions 20b and 21b are extended in the axial direction. The tip portions 20c and 21c having a spherical cross section are formed, and the surface roughness of the tip portions 20c and 21c is made finer than that of the radial direction portions 20a and 21a and the axial direction portions 20b and 21b. In addition, the stress distribution is performed in the axial direction portions 20b and 21b to increase the adhesive force, and the corona stabilizing action acts on the distal end portions 20c and 21c, so that the electric field can be reduced.

  Next, a mold vacuum valve according to a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is an enlarged cross-sectional view showing a main part of the configuration of the mold vacuum valve according to the second embodiment of the present invention. The second embodiment is different from the first embodiment in the shape of the electric field relaxation shield axial direction portion. In FIG. 3, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Since the fixed side and the movable side have the same shape, description will be made using the fixed side.

  As shown in FIG. 3, a plurality of annular grooves 20 b 1 are provided on both side surfaces of the axial portion 20 b of the fixed-side electric field relaxation shield 20. The width and depth of the groove 20b1 are several hundreds μm or more, which is larger than the surface roughness of the base. This is because, in general, since the axial insulation thickness of the mold vacuum valve is larger than that in the radial direction, the axial stress increases. Thereby, in particular, axial stress distribution can be performed.

  According to the mold vacuum valve of the second embodiment, in addition to the effects of the first embodiment, the axial stress distribution can be further achieved.

  Next, a mold vacuum valve according to Example 3 of the present invention will be described with reference to FIG. FIG. 4 is an enlarged cross-sectional view of a main part showing the configuration of the mold vacuum valve according to Example 3 of the present invention. The third embodiment is different from the second embodiment in the shape of the electric field relaxation shield tip. In FIG. 4, the same components as those in the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 4, the front end portion 20c of the fixed-side electric field relaxation shield 20 has an elliptical cross section. The elliptical ellipse side is arranged in parallel with the axial direction, and the radius of curvature of the portion facing the ground layer 13 is increased.

  According to the mold vacuum valve of the third embodiment, in addition to the effects of the second embodiment, it is possible to reduce the electric field between the ground layers 13 that is the shortest insulation distance.

DESCRIPTION OF SYMBOLS 1 Vacuum insulating container 2 Fixed side sealing metal fitting 3 Movable side sealing metal fitting 4 Fixed side energizing shaft 5 Fixed side contact 6 Movable side contact 7 Movable side energizing shaft 8 Bellows 9 Arc shield 10, 20 Fixed side electric field relaxation shield 11, 21 Movable-side electric field relaxation shield 12 Insulating layer 13 Ground layers 14 and 15 Interface connection portions 20a and 21a Radial direction portions 20b and 21b Axial direction portions 20b1 Grooves 20c and 21c Tip portions

Claims (4)

A tubular vacuum insulated container;
A fixed-side sealing metal fitting and a movable-side sealing metal fitting sealed at both ends of the vacuum insulating container; and
A fixed-side energizing shaft that is fixedly penetrated to the fixed-side sealing fitting;
A fixed-side contact fixed to the fixed-side energizing shaft end;
A movable contact that contacts and separates from the fixed contact;
A movable side energizing shaft that sticks the movable side contact and penetrates the movable side sealing fitting in an airtight manner,
A fixed-side electric field relaxation shield provided to cover an outer peripheral end of the fixed-side sealing metal fitting,
A movable-side electric field relaxation shield provided so as to cover an outer peripheral end of the movable-side sealing metal fitting,
Comprising an insulating layer formed by molding an insulating material on the outer periphery of the vacuum insulating container and the electric field relaxation shield,
Each of the electric field relaxation shields includes a radial portion extending in the radial direction, an axial direction portion extending in the axial direction, and a tip portion, and the surface roughness of the tip portion is finer than that in the radial direction portion and the axial portion. Mold vacuum valve characterized by that.   The mold vacuum valve according to claim 1, wherein a plurality of annular grooves are provided in the axial direction portion.   3. The mold vacuum valve according to claim 1, wherein the tip portion has a spherical shape in cross section and a diameter thereof is larger than a thickness of the axial direction portion.   3. The mold vacuum valve according to claim 1, wherein the tip end portion has an elliptical cross section and the ellipse side is disposed in the axial direction. 4.

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