JP2009193734A - Resin mold vacuum bulb - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a resin mold vacuum bulb small in residual stress, and large in electrical field moderation effect. <P>SOLUTION: The vacuum bulb is equipped with a vacuum insulated container 1, a fixed side sealed metal fitting 2, a movable side sealing metal fitting 3 sealed on both end opening parts of the vacuum insulated container 1, a fixed side energization axis 4 fixed to the fixed side sealed metal fitting 2, a fixed side internal shield 5 installed at an intermediate part of the fixed side energization axis 4, a fixed side contact 6 installed on the end of the fixed side energization axis 4, a movable side energization axis 8 to penetrate through the movable side sealed metal fitting 3, a movable side contact 7 installed at the end of the movable side energization axis 8, a bellows 9 sealed between the movable side energization axis 8 and the movable side sealed metal fitting 3, a movable side internal shield 11 installed at the movable side sealing metal fitting 3, a fixed side external shield 13 installed so as to surround one end of the vacuum insulated container 1, a movable side external shield 14 installed so as to surround the other end of the vacuum insulated container 1, and an insulating layer 15 installed at the outer periphery of the vacuum insulated container 1, the fixed side external shield 13, and the movable side external shield 14. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a resin-molded vacuum valve in which a vacuum valve having a pair of contactable and separable contacts is molded with an insulating material.

  The vacuum valve has an advantage that the outer shape can be made compact because the inside of the vacuum insulating container that houses a pair of contactable and separable contacts is kept at a high vacuum and has an excellent dielectric strength. However, outside the vacuum insulation container, there is a problem that the creeping insulation distance is short and it is difficult to apply to a high voltage.

Therefore, a resin mold vacuum valve that secures a creeping insulation distance by molding an insulating material such as an epoxy resin around a vacuum insulating container is conventionally known. In this case, since the ends of the sealing fittings sealed at the opening portions at both ends of the vacuum insulation container are sharp edges, and the electric field strength is increased, a metal bowl-shaped electric field relaxation shield covering the sealing fittings is provided. Is provided. The electric field relaxation shield extends until the end of the electric field relaxation shield wraps with the vacuum insulation container, and is molded integrally with the vacuum insulation container (see, for example, Patent Document 1).
JP 2005-285430 A (3rd page, FIG. 6)

The above-mentioned conventional resin mold vacuum valve has the following problems.
Although the electric field strength at the end of the metal fitting can be reduced by the electric field relaxation shield, the residual stress in the insulating layer after molding becomes excessive due to the difference in thermal expansion coefficient between the electric field relaxation shield and the epoxy resin, which causes cracks. Sometimes.

  The longer the length of the electric field relaxation shield in the axial direction and the longer the distance at which the end of the electric field relaxation shield wraps with the vacuum insulating container, the greater the effect of electric field relaxation, but the corresponding residual stress in the insulating layer increases. . Conversely, if the distance to wrap with the vacuum insulating container is shortened, the residual stress is reduced, but the effect of electric field relaxation is reduced. For this reason, there has been a demand for an electric field relaxation shield that can sufficiently exert an electric field relaxation effect and can reduce residual stress. Moreover, total electric field relaxation including the inside of a vacuum insulating container has been desired.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a resin mold vacuum valve in which an electric field relaxation shield having a small residual stress in an insulating layer and a large electric field relaxation effect is embedded.

  In order to achieve the above object, a resin mold vacuum valve of the present invention comprises a cylindrical vacuum insulating container, a fixed-side sealing metal fitting sealed at one end opening of the vacuum insulating container, and the fixed-side sealing. A fixed-side energizing shaft that is fixed through the fitting, a fixed-side inner shield that is provided at an intermediate portion of the fixed-side energizing shaft and that faces the one end of the vacuum insulating container, and the fixed side A fixed-side contact provided at the end of the energizing shaft, a movable-side sealing fitting sealed at the other end opening of the vacuum insulating container, and a movable-side energizing shaft that movably penetrates the movable-side sealing fitting; The movable side energizing shaft is provided with a movable side contact that contacts and separates from the fixed side contact, and one end is sealed at an intermediate portion of the movable side energized shaft, and the other end is the movable side sealing bracket. Telescopic bellows sealed on the movable side sealing gold A fixed-side outer shield provided to surround one end of the vacuum insulating container together with a movable-side inner shield disposed so as to surround the middle portion of the bellows, and the fixed-side sealing metal fitting And a movable-side outer shield provided so as to surround the other end of the vacuum insulating container together with the movable-side sealing metal fitting, and provided on an outer periphery of the vacuum insulating container, the fixed-side outer shield, and the movable-side outer shield. And an insulating layer formed thereon.

  According to the present invention, since the outer shield that covers the inner shield provided in the vacuum insulating container together with the sealing fitting is embedded in both ends of the vacuum insulating container in the insulating layer, the residual stress of the insulating layer is suppressed. The electric field of the entire vacuum valve can be reduced.

  Embodiments of the present invention will be described below with reference to the drawings.

  A resin mold vacuum valve according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing a configuration of a resin mold vacuum valve according to an embodiment of the present invention, and FIG. 2 is an enlarged cross-sectional view illustrating the positional relationship of each part of the resin mold vacuum valve according to the embodiment of the present invention. 3 is a characteristic diagram for explaining the relationship between the electric field strength and the residual stress according to the embodiment of the present invention, and FIG. 4 is a characteristic diagram for explaining the relationship between the electric field strength and the internal shield according to the embodiment of the present invention. .

  As shown in FIG. 1, a fixed-side sealing fitting 2 and a movable-side sealing fitting 3 are sealed at both ends of the vacuum insulating container 1. A fixed-side energizing shaft 4 is fixed through the fixed-side sealing fitting 2, and a hook-shaped fixed-side inner shield 5 is provided in the middle of the vacuum insulating container 1, and a fixed-side contact 6 is provided at the end. A movable contact 7 that can be moved toward and away from the fixed contact 6 is provided at the end of the movable energizing shaft 8 that movably penetrates the movable seal 3.

  One end of a telescopic bellows 9 is sealed together with the arc shield 10 at the intermediate portion of the movable side energizing shaft 8, and the other end is sealed to the movable side sealing fitting 3. The movable-side sealing metal fitting 3 is provided with a cylindrical movable-side inner shield 11 arranged so that the end thereof covers up to the middle part of the bellows 9. Thereby, the movable side contact 7 can move in the axial direction while maintaining the vacuum in the vacuum insulating container 1. A cylindrical arc shield 12 surrounding the fixed side contact 6 and the movable side contact 7 is fixed to an intermediate portion in the vacuum insulating container 1.

  Outside the vacuum insulating container 1, a cylindrical fixed-side outer shield 13 is fixed to the fixed-side sealing metal fitting 2, so that the end of the vacuum-side insulating container 1, together with the fixed-side sealing metal fitting 2, surrounds one end of the vacuum insulating container 1. Is provided. In addition, a cylindrical movable outer shield 14 is fixed to the movable-side sealing metal fitting 3 and is provided so as to surround the other end of the vacuum insulating container 1 together with the movable-side sealing metal fitting 3. . An insulating layer 15 molded with an insulating material such as an epoxy resin is formed on the outer periphery of the vacuum insulating container 1, the fixed outer shield 13, and the movable outer shield 14. The fixed-side outer shield 13 and the movable-side outer shield 14 are embedded in the insulating layer 15 with a predetermined distance from the vacuum insulating container 1. At both ends of the insulating layer 15, tapered interface connecting portions 15a are provided on both the fixed side and the movable side, and other electric devices (not shown) are connected. On the outer periphery, a grounding layer 16 coated with a conductive paint is provided.

  Next, details of the positional relationship between the inner shields 5 and 11 and the outer shields 13 and 14 will be described with reference to the fixed side shown in FIG. The movable side is also in the same positional relationship.

  First, assuming that the distance between the bottoms of the fixed-side sealing fitting 2 and the fixed-side inner shield 5 is L1, and the distance between the tips of the fixed-side sealing fitting 2 and the fixed-side outer shield 13 is L2, L2> L1. That is, the distal end of the fixed side outer shield 13 extends in the direction of the fixed side contact 6 rather than the fixed side inner shield 5.

  This relationship will be described with reference to FIG. In FIG. 3, the horizontal axis is L2 / L1, and the vertical axis is the creeping electric field strength on the inner surface of the vacuum insulating container 1 and the residual stress in the insulating layer 15. The creeping electric field strength decreases rapidly when the ratio of L2 / L1 is increased, and has a characteristic of gradually decreasing from a region where L2 / L1 = 0.4 or more. Residual stress increases linearly in proportion to the ratio of L2 / L1, the rate of increase decreases from the point of L2 / L1 = 1, and the resin machine starts from the region where L2 / L1 = 1.3 or more. The characteristic exceeds the critical value of the mechanical strength.

  Accordingly, L2 / L1 = 0.4 or more is good for suppressing the creeping electric field strength, and L2 / L1 = 1.3 or less is good for suppressing the residual stress. Here, in order to satisfy both the creeping electric field strength and the residual stress, L2 / L1 = 0.4 to 1.3. However, in order to effectively suppress the residual stress, a range of L2 / L1 = 1 excess to 1.3 with a small increase rate is preferable.

  That is, in the region of L2> L1, the creeping electric field strength can be sufficiently suppressed, and the increase in the residual stress due to the axial length of the fixed-side outer shield 13 becomes slow, and the residual stress is effectively suppressed. If L2 = 1.3 is exceeded, not only the residual stress exceeds the critical value, but also the axial length of the fixed-side outer shield 13 becomes long, and the interval adjustment for coaxial mounting with the vacuum insulating container 1 is possible. It becomes difficult. In addition, it is preferable to manufacture the fixed-side outer shield 13 by drawing a metal cylinder such as a thin copper plate because the residual stress is absorbed.

  Next, as shown in FIG. 2, when the outer diameter of the fixed-side inner shield 5 is D1, and the inner diameter of the vacuum insulating container 1 is D2, D1 / D2 = 0.8 to 0.9. As shown in FIG. 4, in order to suppress the creeping electric field strength of the vacuum insulating container 1, the outer diameter D <b> 1 of the fixed-side inner shield 5 is preferably as large as possible, and the outer circumference does not contact the creeping surface of the vacuum insulating container 1. Because it is good. Further, assuming that the outer diameter of the vacuum insulating container 1 is D3 and the outer diameter of the fixed-side outer shield 13 is D4, D3 / D4 = 0.8 to 0.9. This also minimizes the outer diameter D4 of the fixed-side outer shield 13 so that it does not contact the outer periphery of the vacuum insulating container 1. When the outer diameter of the insulating layer 15 is D5, D4 / D5 = 0.8 to 0.9.

  That is, the fixed-side inner shield 5 and the fixed-side outer shield 13 are arranged so as to be sandwiched between the inside and the outside of the end of the vacuum insulating container 1, and these are arranged coaxially with the same dimensional ratio. Furthermore, the outer diameter of the insulating layer 15 is also coaxially arranged with the same dimensional ratio. Thereby, there is little disturbance in the electric field distribution from the stationary energizing shaft 4 to the ground layer 16, which is favorable.

  Here, the inner and outer diameters of the fixed inner shield 5, the vacuum insulating container 1, the fixed outer shield 13, and the insulating layer 15 have some errors due to manufacturing variations and mounting dimensional accuracy. For this reason, it is difficult to make the dimensional ratios of D1 / D2, D3 / D4, and D4 / D5 all the same. However, if each dimensional ratio is within the above range, a good electric field distribution can be obtained. For this reason, the ratio of the inner and outer diameters of the fixed inner shield 5, the vacuum insulating container 1, the fixed outer shield 13, the insulating layer 15 and the like are set equal to each other within the range of 0.8 to 0.9. Defined as a range.

  Note that it is more preferable that the distance from the outer periphery of the vacuum insulating container 1 to the fixed outer shield 13 is smaller than the distance from the inner periphery of the vacuum insulating container 1 to the fixed inner shield 5. This is because they have a coaxial electrode arrangement. Further, in order to further suppress the electric field strength, the outer diameter D5 of the insulating layer 15 may be increased to reduce the above-described ratio.

  Next, as shown in FIG. 2, assuming that the radius of curvature of the end of the fixed inner shield 5 is R1, and the radius of curvature of the end of the fixed outer shield 13 is R2, R1> R2. This is because the dielectric strength of the insulating layer 15 is greater than in vacuum and the radius of curvature R2 of the fixed outer shield 13 can be reduced. That is, the curvature radii R1 and R2 are determined in accordance with the dielectric strength of the portion where the shields 5 and 13 are provided.

  The curvature of the end of the fixed side outer shield 13 is bent with, for example, three stages of curvature radii. Bending from the outer periphery first with the largest radius of curvature, then with a smaller radius of curvature, and finally with the smallest radius of curvature, the fixed outer shield 13 having a small outer diameter and a large electric field relaxation effect is obtained. be able to.

  From these things, the electric field relaxation of the fixed side ends inside and outside the vacuum insulating container 1 is reduced by the fixed side outer shield 13 embedded in the insulating layer 15 that covers up to the fixed side inner shield 5 together with the fixed side sealing metal fitting 2. Can be planned. Moreover, since the radius of curvature of the fixed-side inner shield 5 can be increased, the creeping electric field strength on the inner surface of the vacuum insulating container 1 can be significantly suppressed. In addition, the axial length of the fixed-side outer shield 13 that wraps with the vacuum insulating container 1 is set to the minimum length, and the region where the rate of increase in the residual stress is slow is used, so that the residual stress is suppressed. Can do.

  And the electric field of the whole vacuum valve can be eased by making the movable side into the same configuration. On the movable side, the electric field distribution differs from the fixed side due to the outer shape of the bellows 9 and the arc shield 10, so the positional relationship and the radius of curvature of the movable side inner shield 11 and the movable side outer shield 14 need to be the same as those on the fixed side. There is no.

  According to the resin mold vacuum valve of the above embodiment, the outer shields 13 and 14 embedded in the insulating layer 15 cover the inner shields 5 and 11 together with the sealing fittings 2 and 3, so that the electric field of the entire vacuum valve is reduced. And the residual stress of the insulating layer 15 can be suppressed.

Sectional drawing which shows the structure of the resin mold vacuum valve which concerns on the Example of this invention. The expanded sectional view explaining the positional relationship of each part of the resin mold vacuum valve which concerns on the Example of this invention. The characteristic view explaining the relationship between the electric field strength which concerns on the Example of this invention, and a residual stress. The characteristic view explaining the relationship between the electric field strength and the inner shield according to the embodiment of the present invention

Explanation of symbols

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 inner shield 6 Fixed side contact 7 Movable side contact 8 Movable side energizing shaft 9 Bellows 10, 12 Arc shield 11 Movable side inside Shield 13 Fixed side outer shield 14 Movable side outer shield 15 Insulating layer 15a Interface connection 16 Grounding layer

Claims (5)

A tubular vacuum insulated container;
A fixed-side sealing fitting sealed at one end opening of the vacuum insulating container;
A fixed-side energizing shaft that is fixedly penetrated to the fixed-side sealing fitting;
A fixed-side inner shield that is provided at an intermediate portion of the fixed-side energization shaft and is arranged to face one end of the vacuum insulating container;
A fixed-side contact provided at the fixed-side energizing shaft end;
A movable-side sealing fitting sealed at the other end opening of the vacuum insulating container;
A movable-side energizing shaft that movably penetrates the movable-side sealing fitting;
A movable side contact provided at the movable side energizing shaft end and contacting and separating from the fixed side contact;
A telescopic bellows whose one end is sealed to the middle portion of the movable-side energizing shaft and whose other end is sealed to the movable-side sealing metal fitting,
A movable side inner shield disposed on the movable side sealing bracket and disposed so as to surround the middle part of the bellows,
Along with the fixed-side sealing fitting, a fixed-side outer shield provided so as to surround one end of the vacuum insulating container,
A movable side outer shield provided so as to surround the other end of the vacuum insulating container together with the movable side sealing metal fitting,
A resin mold vacuum valve comprising: the vacuum insulating container; the fixed outer shield; and an insulating layer provided on an outer periphery of the movable outer shield. The distance between the fixed-side sealing bracket and the fixed-side inner shield, and the distance between the movable-side sealing bracket and the movable-side inner shield are L1, and the distance between the fixed-side sealing bracket and the fixed-side outer shield tip, And when the distance between the movable side sealing bracket and the movable side outer shield tip is L2,
2. The resin mold vacuum valve according to claim 1, wherein L2> L1 at least on the fixed side. The ratio of the outer diameter of the fixed side inner shield and the movable side inner shield, and the inner diameter of the vacuum insulating container,
The ratio between the outer diameter of the vacuum insulating container and the outer diameter of the fixed-side outer shield and the movable-side outer shield,
The resin mold vacuum valve according to claim 1 or 2, wherein at least a fixed range is set in an equivalent range. The radius of curvature of the fixed side inner shield and the movable side inner shield is larger than the radius of curvature of the fixed side outer shield and the movable side outer shield end.
The resin mold vacuum valve according to any one of claims 1 to 3, wherein the resin mold vacuum valve is increased at least on a fixed side.   The resin mold vacuum valve according to any one of claims 1 to 4, wherein the fixed outer shield and the movable outer shield are manufactured by drawing.

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