JPH0439626Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains] This invention consists of a bellows that is vacuum-tightly fixed to a movable contact rod that is formed in a cylindrical shape and passes through the bottom surface of the rod in the axial direction, and The movable contact rod is integrally fixed to the flange surface of a shield member which vacuum-tightly seals the opening of the vacuum container, and is integrally fixed to the flange surface of the shield member, which is formed by a ring-shaped flange extending in the direction of the shield member, and prevents movement of the movable contact rod. The present invention relates to a structure of a vacuum valve guide having a ring-shaped adhesive surface and improving the reliability of adhesion to the flange surface.

[Prior art and its problems]

FIG. 4 shows an example of the structure around the opening of the vacuum vessel on the movable contact side in a conventional vacuum valve. The bellows 2, which is formed in a cylindrical shape with a bottom, is vacuum-tightly fixed to a movable contact rod 6 having a movable contact 6a at its tip, which passes through the bottom surface 2a of the bellows 2 in the axial direction. A ring-shaped flange portion 3 formed by extending the outer circumference on the end side is vacuum-tightly fixed to the opening end surface of a cylindrical vacuum container 7 made of porcelain, glass, etc., and maintains the vacuum container at a high vacuum. . The guide 5, which guides the vertical movement of the movable contact rod 6 that moves vertically to contact and separate from a fixed contact (not shown) when the current is turned on and off, is composed of a cylindrical guide portion 5a and a ring-shaped flange portion 5b. On the lower surface of the flange portion 5b, the flange portion 3 of the shield member 1 is fixed integrally with the adhesive 4 so as to be concentric with the movable contact rod 6.

The material used for the guide 5 is polyamide or polyethylene terephthalate resin, which has excellent sliding properties and wear resistance, and the adhesive used to fix the guide 5 and the shield member 1 has excellent heat resistance and adhesive properties. A silicone elastomer is used. However, the lower surface of the flange portion 5b of the guide 5, that is, the ring-shaped adhesive surface, and the flange surface of the shield member to which this adhesive surface is fixed are both formed flat, and when they are fixed to both, it is necessary to Since the adhesive is simply applied and pressed together, the thickness of the adhesive is not uniform, resulting in thicker areas and thinner areas. Therefore, when the guide 5 receives lateral pressing force or rotational force when the movable contact rod moves in the axial direction,
The force is concentrated in the thinner part with less cushioning effect,
There is a risk that peeling will begin from this part and the guide will no longer function or fall off.
When the guide peels off, the outer circumferential side of the cylindrical guide portion 5a hits the inner circumferential side of the bellows 2, damaging the bellows and causing vacuum leakage, and causing damage to the movable contact rod 6 and fixed contact rod (not shown). There is a risk that the axial parallelism of the line will be impaired, which may adversely affect the interrupting performance. In order to solve this problem caused by peeling, we use an adhesive material such as epoxy resin, which has a large absolute value of adhesive force even if the thickness is uneven during bonding, and has an extremely low risk of peeling. There are possible ways. However, epoxy resin does not have the same elasticity as silicone elastomer and has poor cushioning properties, and although its coefficient of linear expansion is close to that of the material of the guide 5, it is significantly larger than that of a shield member made of metal, and the wall thickness of the shield member is Because it is thin, it can be fixed via the movable contact rod 6.
The shield member 1 is caused by the repeated rise and fall of the temperature transmitted from the contact portion of both movable contacts to the guide 5.
If excessive strain occurs repeatedly, the bellows may become deformed or cracked, leading to vacuum leakage.

[Purpose of invention]

This idea improves the adhesion reliability between the guide and the shield member, and also reduces the stress generated in the shield member, especially the bellows, due to expansion and contraction of the guide due to temperature changes. The purpose is to provide an adhesive structure.

[Key points of the idea]

This idea provides a protrusion of a predetermined uniform height on the lower surface of the flange of the guide, that is, a ring-shaped adhesive surface, and the tip of this protrusion is brought into contact with the surface of the flange of the shield member. By creating a uniform gap between the parts and the entire surface,
By applying adhesive to the ring-shaped adhesive surface of the guide and the adhesive surface of the shield member, the thickness of the adhesive is made uniform when they are pressed together, and the lateral pressure applied to the guide when the movable contact rod moves in the axial direction is reduced. In addition to avoiding uneven distribution and concentration of rotational force on a part of the adhesive surface,
By using a silicone elastomer that has heat resistance and adhesive properties as well as cushioning properties, that is, elasticity, and ensuring a thickness of 0.2 mm or more, the expansion and contraction of the guide due to temperature changes will prevent the shield member, especially the bellows. The aim is to reduce the strain that occurs in the bellows area and effectively relieve stress in the bellows. At the same time, we also focused on the fact that the mechanical strength of the adhesive itself depends on the thickness of the adhesive layer, so we limited the thickness of the adhesive to a range of 0.2 to 1.0 mm.
This is intended to ensure the mechanical strength of the adhesive itself by avoiding a decrease in the mechanical strength of the adhesive itself within the thickness of the adhesive.

[Example of idea]

Embodiments of the present invention are shown in FIGS. 1 to 3.
The guide 15 is made in the same shape as the conventional guide 5 (Fig. 4), but the adhesive surfaces 16 and 17 are provided with a ring-shaped protrusion 18 (Fig. 2) or a plurality of small cylindrical protrusions 19 (third The difference from the guide 5 is that the guide 5 is provided with the guide 5 shown in FIG. These projections 18, 19
Since the protrusions are formed at the same time as the guide is molded, the cost does not increase due to the provision of the protrusions. For bonding, silicone elastomer adhesive is applied to the bonding surfaces 16, 17 of the guide and the bonding surface of the shield member 1, and then the protrusions 18, 19 are bonded.
Press until it touches the adhesive surface of the shield member, and remove any excess adhesive that protrudes. In this way, it is possible to obtain an adhesive layer having a uniform thickness and having the desired adhesive strength on the respective adhesive surfaces of the guide and the shield member. This eliminates the fact that the lateral pressure and rotational force when the movable contact rod moves is applied unevenly to a part of the adhesive surface, and these forces are uniformly received over the entire area of the adhesive surface, significantly improving peel resistance. do. In addition, since this adhesive forms an elastic layer with a predetermined thickness, even if the guide expands and contracts due to temperature changes, the strain that occurs in the bellows will be smaller than the amount of expansion and contraction, and the stress will be effectively alleviated. Ru. At the same time, the adhesive itself can ensure a predetermined mechanical strength in the directions perpendicular and parallel to the adhesive surface.

[Effect of idea]

As described above, according to the present invention, protrusions of the same height are provided on the ring-shaped adhesive surface of the guide, for example, in the range of 0.2 to 1.0 mm, and the adhesive has heat resistance, adhesion, and cushioning properties. Since silicone elastomer with high properties is used, (1) a layer of adhesive with a uniform thickness can be obtained between the guide and the shield member, and the lateral pressure and rotation acting on the guide when the movable contact rod moves can be applied to the adhesive. Since these forces are not applied unevenly to a part of the surface and are uniformly received over the entire area of the adhesive surface, the peel resistance is significantly improved.

(2) Since the adhesive forms an elastic layer with a predetermined thickness, there will be no distortion in the bellows even if the guide expands or contracts due to changes in temperature transmitted from the contact area between the fixed and movable contacts of the vacuum valve. is smaller than this amount of expansion/contraction, the stress is effectively alleviated, and the bellows is less likely to be damaged.

(3) Since an upper limit is set for the thickness of the adhesive layer, the mechanical strength of the adhesive itself is ensured, and together with the effect of a uniform adhesive layer, the peel resistance is improved.

Effects such as this can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the main parts showing the bonding structure of a vacuum valve guide constructed based on the present invention, Fig. 2 is a perspective view showing the first embodiment developed from Fig. 1, and Fig. 3. is also a perspective view showing the second embodiment,
FIG. 4 is a sectional view of a main part showing an example of the bonding structure of a conventional vacuum valve guide. 1... Shield member, 2... Bellows, 3...
Flange portion, 4...adhesive, 5...guide, 6...
...Movable contact rod, 7...Vacuum container, 15...Guide, 16, 17...Adhesive surface, 18, 19...Protrusion.

Claims (1)

[Scope of utility model registration request] A shield member consisting of a bellows that is vacuum-tightly fixed to a movable contact rod that is formed in a cylindrical shape and passes through the bottom surface in the axial direction, and a ring-shaped flange portion that is formed by extending the outer circumference of the bellows in the radial direction. A guide that seals the opening of the vacuum container in a vacuum-tight manner and includes a ring-shaped adhesive surface that is integrally fixed to the flange portion of the shield member using an adhesive, and a cylindrical portion that guides the movable contact rod. In the vacuum valve, a protrusion of a predetermined height is provided on the ring-shaped adhesive surface of the guide so that a uniform gap is created between the ring-shaped adhesive surface and the flange surface, and the end surface of the protrusion is A guide for a vacuum valve, characterized in that the guide is fixed to the flange portion by filling an adhesive into a gap formed between the ring-shaped adhesive surface and the flange portion.