JPH052321U - Composite insulator - Google Patents

Abstract

(57) [Summary] [Purpose] The deviation when a tensile load is applied is small,
It also provides a composite insulator with a large breaking load. [Structure] In a composite insulator having a grip portion formed by joining a reinforced plastic rod 2 and a holding metal fitting 1 having a taper hole that has been subjected to a mold release process with a resin 4, a taper taper surface 3 is provided from the entrance of the hole. A curved composite insulator whose taper angle increases continuously as it goes to the bottom of the hole.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a composite insulator (insulator) having a grip portion in which a grip fitting is joined to a reinforced plastic rod (FRP).

[0002]

[Prior Art]

 The following three types of composite insulators in which an FRP and a gripping metal are joined are known. That is, (1) a straight FRP is directly caulked with a metal fitting, (2) a hole of the metal fitting is made into a taper hole that expands inward, and a straight FRP is inserted into this hole, and the gap between the metal fitting and the FRP is bonded with resin. (3) Similarly, the bottom of the tapered hole has two or four split wedges in the center, a straight FRP is inserted into this hole, and the end is split with a wedge. Is.

FIG. 2 is a partially cutaway cross-sectional view showing the composite insulator of (2). Reference numeral 1 denotes a metal fitting having a tapered hole with an inner diameter. The FRP2 is inserted into the hole, and the bonding resin 4 is filled in the gap between the metal fitting 1 and the FRP2 and fixed by adhesion. The adhesive resin 4 firmly adheres to the FRP 2, but is separated from the tapered surface 3 so that the joining resin 4 and the metal fitting 1 can slide. When a tensile load P is applied to the FRP 2, the taper surface 3 slides, and a gap 5 is formed at the bottom of the hole, causing a deviation t. At this time, surface pressure is generated on the taper surface due to the wedge effect. This surface pressure is transmitted to the interface between the FRP 2 and the bonding resin 4, and the same effect as that of the caulked bonding of (1) is obtained. In the case of this taper joining, since there is an adhesive force between the FRP and the joining resin in addition to the effect of caulking, it is more reliable than simple caulking. After all, the joint length l ₀ is short, and the total length and weight of the composite insulator can be reduced.

[0004]

[Problems to be solved by the device]

 In practice, apply a tensile load above the maximum load that may be applied during use as a composite insulator. At this time, if the deviation t is too large, inconvenience occurs in terms of dimensional tolerance. The taper angle (θ) influences the magnitude of the deviation t, and the smaller the θ, the larger the deviation t under the same tensile load. On the contrary, if θ is increased, stress concentration in the FRP near the inlet of the metal fitting (c in Fig. 2) becomes large when a tensile load is applied, and the FRP breaks at this part and the fracture load also decreases. Tend to do. That is, it is not possible to simultaneously reduce the deviation and increase the breaking load only by changing θ.

The object of the present invention is to achieve both requirements at the same time.

[0006]

[Means for Solving the Problems]

 The present invention relates to a composite insulator having a grip portion formed by joining a reinforced plastic rod (FRP) and a gripping metal fitting having a taper hole that has been released from the mold with a resin. This relates to a curved insulator that has a taper angle that continuously increases from the bottom to the bottom of the hole.

In the present invention, the taper angle of the tapered hole in the grip is continuously increased toward the bottom of the hole. FIG. 1 is a view showing the structure of a composite insulator according to an embodiment of the present invention, in which a grasping tool 1 is provided with a tapered hole having a curved tapered surface, and a bonding resin 4 is provided between the tapered surface 3 and the FRP 2. It is filled and the tensile load P is applied to the FRP 2 to join the metal fitting 1 and the FRP 2 together. Reference numeral 5 is a void formed at the bottom of the hole. In Fig. 1, the taper angle at the hole inlet (θa) is made smaller than the uniform taper angle (at θ ₀ ) of the tapered hole in the conventional composite insulator of Fig. The stress concentration is weakened to improve the fracture load, the taper angle (θb) toward the bottom of the hole is increased to reduce the deviation t, and the angle from the entrance of the hole to the bottom of the hole is continuous. It's big. If the angle is increased discontinuously, for example, it will be smaller than θ ₀ at a depth of 2/3 from the entrance, and the remaining 1/3 will be larger than θ ₀ , new stress concentration will occur near the boundary where this angle changes. It is not preferable because it occurs.

In order to obtain the composite insulator of the present invention, first, a mold release agent is applied to the inner surface of the tapered hole of the metal fitting 1 having the curved tapered hole, and then the bonding resin is put into the tapered hole, The FRP 2 is inserted therein, the bonding resin 4 is spread over the gap between the metal fitting 1 and the FRP 2, and is cured by heating, and the resin 4 is bonded to the FRP 2. Next, a tensile load P is applied to the FRP 2 at room temperature to slide the tapered surface 3 so that surface pressure is applied from the surroundings by the wedge effect.

[0009]

【Example】

Next, an embodiment of the present invention will be described. The metal fitting 1 in FIG. 1 is a castable black-core malleable cast iron, the inlet diameter of the tapered hole is 21 mm, and the depth of the tapered hole is 35 mm. Taper angle, the constant ₀ theta in Comparative Example 3. In the embodiment, θa at the entrance of the hole is set to 2.0 ° which is smaller than θ ₀ and θb at the tip of the bottom of the hole is set to 5.0 ° which is larger than θ ₀ to form a gentle curved surface from the entrance to the bottom. did. The FRP 2 was a 20 mm diameter epoxy-E glass pultruded rod (G141A manufactured by Nitto Denki Kogyo), and the bonding resin 4 was a silica powder-filled epoxy resin (KE-5221 manufactured by Hitachi Chemical Co., Ltd.).

After applying a silicone type release agent (QZ-13 made by Ciba-Geigy Japan) to the inner surface of the tapered hole of the metal fitting 1 and polishing the bonding surface of the FRP 2 with sandpaper No. 150, the inside of the hole of the metal fitting 1 The bonding resin was injected into, and FRP2 was inserted into it and pushed to the bottom of the hole, the excess bonding resin overflowing from the hole mouth was wiped off, and the bonding resin was cured at 120 ° C for 2 hours. ..

Regarding the composite insulators joined in the example and the comparative example, a tensile load P of 60 KN was applied to each FRP2, and the resulting deviation t was determined by measuring the change in the length of the gripping metal. Was 3 mm, whereas the embodiment has half of 1. It was 5 mm. When the load P was further increased to determine the breaking load at which the FRP2 broke, the comparative example had a breaking load of 150 KN, while the working example showed a large value of 180 KN.

The relationship between the distance x from the bottom of the tapered hole and the maximum tensile stress on the FRP surface was calculated by a stress analysis by a computer when the tensile load was 150 KN, and the results are shown in FIG. From the distribution of tensile stress in FIG. 3, it is about 0.48 KN / mm ² which is constant outside the metal fitting. In the range where X inside the metal fitting is within about 25 mm, the tensile stress is large as in the example, but it is sufficiently smaller than the tensile strength of FRP of about 0.85 KN / mm ² . When x is 35 mm, that is, the tensile stress on the surface of the FRP becomes maximum at the entrance of the metal fitting, it is 0.85 KN / mm ² in the comparative example, and it is a roller when it has already broken, but it is still 0.70 KN / mm ² in the example. is there. In this way, by gradually increasing the taper angle of the tapered hole of the metal fitting from the entrance to the back (to the bottom), the tensile stress acting on the FRP is pushed toward the back and the stress concentration near the entrance is relieved. However, the breaking load can be improved.

[0013]

[Effect of the device]

 The composite insulator of the present invention has a small displacement when a tensile load is applied and a large breaking load.

[Brief description of drawings]

FIG. 1 is a partial cutaway sectional view showing a structure of a composite insulator according to an embodiment of the present invention.

FIG. 2 is a partially cutaway sectional view showing a structure of a conventional composite insulator.

FIG. 3 is a graph showing the relationship between the distance x from the bottom of the tapered hole of the metal fitting and the maximum tensile stress on the FRP surface.

[Explanation of symbols]

1 ... Metal fitting 2 ... FRP 3 ... Tapered surface 4 ... Bonding resin 5 ... Void

Claims (1)

[Claims for utility model registration] [Claim 1] A composite insulator having a grip portion formed by joining a reinforced plastic rod and a grip metal fitting having a taper hole with an inward spread, which has been subjected to mold release, with a resin, A composite insulator with a tapered surface in which the taper angle increases continuously from the hole entrance to the hole bottom.