JP5138318B2 - Pin insulator and manufacturing method thereof - Google Patents

Description

  The present invention relates to a pin insulator in which a resin sheath is attached to the outer surface of a porcelain insulator body and a method for manufacturing the same.

  For example, as a pin insulator that supports an electric wire with a utility pole or the like, a porcelain one is generally used. Such pin insulators have poor water repellency because their outer surfaces are made of porcelain, and leakage currents due to rainwater etc. are likely to increase. The problem is happening.

  Therefore, as disclosed in Patent Document 1, as a pin insulator having salt resistance, a structure in which a jacket made of resin with good water repellency is attached to the outer surface of a porcelain insulator body is proposed. Has been.

  In this pin insulator, a groove for fastening an electric wire with a binding wire is formed at the top of the insulator body, and a metal fitting for attachment to an arm extending from a utility pole is joined to the base of the insulator body, and further, the insulator body The above-described outer cover is attached to the body between the top and the base. The outer casing is formed with a multi-stage brim for increasing the creepage distance.

  In this type of pin insulator, since the insulator body made of porcelain is covered with a sheath body with good water repellency, leakage current due to rain water or the like is difficult to flow. In this way, the maintenance of distribution lines including pin insulators is reduced when used in salt damage areas.

  Conventionally, as a covering body of this pin insulator, there is one using a resin tube having heat shrinkability. When this sheath is attached to a porcelain insulator body, the insulator body is inserted and positioned in a resin tube having a diameter larger than that of the insulator body and molded in advance to a predetermined shape. By heating and shrinking the tube, the resin tube is brought into close contact with the outer peripheral surface of the main body to form an outer cover.

In the case of a pin insulator using such a heat-shrinkable tube as an envelope, not only the material cost is high, but also a heat shrinking process is required, so that there is a problem that the manufacturing cost is also high. . Some resin materials that do not have heat-shrinkability are also excellent in water repellency, and this type of resin material is used for the outer cover, and the outer cover is peeled off and applied to the outer peripheral surface of the main body. It is conceivable to manufacture by die molding such as press molding.
Japanese Patent Laid-Open No. 5-342934

  However, when an outer shell is formed on the outer peripheral surface of the insulator body by die molding such as press molding, there are the following problems due to the structure of the pin insulator.

  When forming the jacket body on the outer peripheral surface of the insulator body of the above-mentioned pin by press molding, the outer base of the insulator body is mounted on the outer periphery of the insulator body with the metal base attached to the base and positioned in the lower mold. After the resin material that becomes the body is attached, the upper mold is brought into contact with the lower mold while being pressed. Thereby, the resin material is molded according to the shape of the cavity formed by the upper and lower molds.

  Here, the pin insulator has a structure in which a metal fitting is fixed to the base of the insulator main body with an adhesive, but moisture may enter between the insulator main body and the metal fitting, and the adhesive may deteriorate over time. In order to prevent this from happening, it is desirable to attach a jacket body from the outer peripheral surface of the insulator body to the outer peripheral surface of the metal fitting. For this reason, when the outer cover is formed by press molding, as described above, the insulator with the metal fitting fixed to the base of the main body is positioned on the lower mold.

  Thus, when setting a pin insulator to a metal mold | die, it is necessary to position to a lower metal mold | die at the two places, ie, the top part of a insulator main body, and the metal fitting attached to the base of the insulator main body. In this case, since the metal fitting is made of metal, it can be elastically deformed and can be positioned accurately in the mold. Even if the metal fitting has a dimensional tolerance, the dimensional tolerance is small. Can be easily positioned.

  However, on the top side of the insulator body, since the insulator body is made of porcelain, the dimensional tolerance is large, so that it is very difficult to accurately position the mold body. If an attempt is made to position the insulator body in the mold while maintaining this large dimensional tolerance, the insulator body may be damaged due to cracks or chipping at the top of the insulator body. In addition, when the insulator body is loaded into the mold with a pressing force that does not cause damage, the gap between the insulator body and the mold increases, resulting in a greater amount of resin leakage and post-processing such as deburring. May become complicated.

  In addition, this insulator body is not necessarily joined to the bracket in a posture standing upright at the center position with respect to the bracket, and the insulator body is inclined with respect to the bracket, that is, the center axis of the insulator body is Positioning the main body of the insulator on the mold becomes more difficult as described above if it is joined off-line or inclined from the straight line passing through the central axis of the bracket. The possibility that the top of the insulator body is damaged is also increased.

  Therefore, the present invention has been proposed in view of the above-mentioned problems, and the object of the present invention is to form a resin jacket on a porcelain insulator body by die molding. It is an object of the present invention to provide a pin insulator and a method for manufacturing the same that enable the top portion to be accurately positioned in a mold.

  As a technical means for achieving the above-mentioned object, the pin insulator according to the present invention has a wire mounting portion to which an electric wire is fastened with a binding wire at the top, and a porcelain having a bottomed cup-shaped fitting fixed to the base. The center of the protrusion provided with the insulator body, the pin insulator having a protrusion with a diameter larger than that of the trunk at the lower part of the wire mounting portion of the insulator body, and the outer peripheral surface of which is polished so as to form a cylindrical surface An insulator body made of a water-repellent resin material formed by die molding in which the insulator body and the metal fitting are joined and integrated so that the shaft is located on the same straight line as the central axis of the metal fitting. The insulator main body and the metal fitting are covered from the outer peripheral surface to the outer peripheral surface of the metal fitting.

  In addition, the manufacturing method of the present invention includes a porcelain insulator body having an electric wire attachment portion at which the electric wire is fastened with a bind wire at the top, and a bottomed cup-shaped fitting fixed to the base portion, and the electric wire attachment of the insulator main body A method of manufacturing a pin insulator in which a protruding portion having a diameter larger than that of the body portion is formed at the lower part of the body, the outer peripheral surface of the protruding portion of the electric wire mounting portion being polished into a cylindrical surface, and the central axis of the protruding portion and the metal fitting After the insulator body and metal fitting are integrated so that the central axis of the insulator is on the same straight line, a water-repellent resin material is applied from the outer peripheral surface of the protrusion of the insulator main body to the outer peripheral surface of the metal fitting. After that, the insulator body is positioned and loaded between the outer peripheral surface of the protruding portion and the outer peripheral surface of the metal fitting, and the insulator main body is pressed from the outer peripheral surface of the protruding portion to the outer peripheral surface of the metal fitting by press molding with the die. And an outer covering for covering the metal fitting.

  In the pin insulator and the manufacturing method thereof according to the present invention, the top portion of the insulator body, that is, the outer peripheral surface of the protrusion of the wire mounting portion is formed by polishing so as to form a cylindrical surface. Tolerance can be reduced. Then, the main body and the metal fitting are joined and integrated so that the central axis of the outer peripheral surface of the protrusion is positioned on the same straight line as the central axis of the metal fitting, so that the protrusion and metal fitting of the electric wire mounting portion are made of metal. It becomes possible to accurately position the mold, and it becomes easy to form the outer cover body by die molding in a region extending from the outer peripheral surface of the insulator body and a part of the outer peripheral surface of the metal fitting.

  In the method of manufacturing a pin insulator according to the present invention, after polishing the outer peripheral surface of the protruding portion of the wire mounting portion, the protruding portion and the metal fitting are joined and integrated with their central axes positioned on the same straight line. In addition, it is desirable to position the main body on the mold by the outer peripheral surface of the protrusion and the outer peripheral surface of the metal fitting.

  In this way, when the insulator body is loaded into the mold, the protrusion and metal fitting of the wire mounting portion are held in the mold, so that the insulator body can be more precisely positioned in the metal fitting by the mold. Positioning can be performed very easily and accurately, and it becomes even easier to form a jacket body on the outer peripheral surfaces of the insulator body and the metal fitting by molding.

  According to the present invention, since the outer peripheral surface of the protrusion of the wire mounting portion that is the top of the insulator body is polished so as to form a cylindrical surface, the dimensional tolerance of the top portion of the insulator body can be reduced, It becomes possible to accurately position the protrusion of the wire mounting portion on the mold. Also, since the main body and the metal fitting are joined and integrated so that the central axis of the outer peripheral surface of the protrusion and the central axis of the metal fitting are positioned on the same straight line, the mold and the metal fitting of the metal It can be securely held by the parts, and the gaps at these holding parts can be remarkably reduced, so that the outer shell of the insulator body and the metal fittings are molded on the outer peripheral surface with high dimensional accuracy and resin leakage is extremely low. By doing so, it becomes easy to realize the formation with reduced burr generation, and it is possible to manufacture a pin insulator suitable for use in a salt damage area at a low cost. In addition, when forming the resin jacket, the protrusions are polished when they are held in contact with and closely attached to the protrusions of the insulator body and the entire circumference of the metal fittings. The metal fittings attached to the other end of the main body are configured so that their central axes are located on the same straight line. There is very little risk of cracking and damage, and a highly insulating pin insulator can be provided.

  Embodiments of the present invention are described in detail below. The pin insulator in this embodiment has a structure in which a jacket made of resin with good water repellency is attached to the outer surface of a porcelain insulator body, and has excellent salt resistance suitable for use in a salt damage area. Demonstrate performance. In this pin insulator, the insulator body made of porcelain is covered with a jacket with good water repellency, so that leakage current due to rainwater etc. does not flow easily, and maintenance of distribution lines including pin insulators is used in salt damage areas Reduction can be achieved.

  FIG. 1 shows an example of the structure of the pin insulator 1 in this embodiment. As shown in the figure, the pin insulator 1 is mainly composed of a porcelain insulator main body 10, a metal fitting 20, and a resin jacket 30 having good water repellency.

  The porcelain insulator main body 10 is composed of a cylindrical body portion 12, a top portion 14 provided at the tip of the body portion 12, and a base portion 15 positioned at the lower end portion of the body portion 12. The electric wire attaching part 16 to which an electric wire is fastened with a bind wire is formed, and a bottomed cup-shaped metal fitting 20 is attached to the base part 15.

  The wire mounting portion 16 includes an annular groove 18 formed on the outer peripheral surface of the insulator body 10 and a straight groove 11 formed on the top surface of the insulator body 10, and the annular groove 18 and the straight groove 11. The wire is fastened with a bind wire using A projecting portion 13 having a diameter larger than that of the body portion 12 is formed at the lower portion of the annular groove 18.

  As will be described later, the outer peripheral surface 13a of the protrusion 13 is polished to form a short cylindrical surface using diamond abrasive grains or the like in order to enable molding of the outer cover 30. By this polishing treatment, the dimensional tolerance on the outer peripheral surface 13a of the protrusion 13 is reduced. The base 15 of the insulator body 10 is accommodated in the bottomed cup-shaped metal fitting 20.

  The metal fitting 20 includes a cup portion 22 and a pin-shaped arm attachment portion 24 led out from a bottom portion 22 a of the cup portion 22. A male screw 24a is formed on the outer peripheral surface of the end portion of the arm mounting portion 24, and an arm mounting nut 26 is screwed to the male screw 24a in the drawing. The cup portion 22 of the metal fitting 20 is fixed to the base portion 15 of the main body 10 with an adhesive 40 such as cement.

  The resin jacket 30 is made of a polymer material having good water repellency, such as silicone rubber, modified silicone rubber, ethylene propylene rubber (EPR), or ethylene / vinyl acetate copolymer (EVA). Is formed in a cylindrical shape, and multistage flange portions 32a and 32b are formed on the outer periphery thereof. The flange portions 32a and 32b are arranged such that large-diameter flange portions 32a and small-diameter flange portions 32b are alternately arranged to increase the creepage distance.

  The jacket 30 is attached from the outer peripheral surface 13 a of the projection 13 located on the top 14 of the insulator body 10 to the outer peripheral surface of the cup portion 22 of the metal fitting 20. Adhesives 42 and 44 such as silicone resin are applied to both ends of the outer cover 30 between the outer peripheral surface 13 a of the protrusion 13 and the outer peripheral surface of the cup portion 22. By covering a part of the cup portion 22 with the outer cover body 30, the aging deterioration of the adhesive 40 such as cement interposed between the cup portion 22 and the insulator body 10 is prevented in advance.

  The pin insulator 1 having the above configuration is attached in an upright state by screwing an arm attachment portion 24 protruding from the metal fitting 20 to an arm extending from the utility pole, and is annularly connected to the wire attachment portion 16 at the top portion 14 of the insulator body 10. The electric wire is held by fastening the electric wire with the binding wire using the groove 18 and the straight groove 11.

  This pin insulator 1 covers the insulator main body 10 made of porcelain with a jacket 30 having good water repellency, so that leakage current due to rain water or the like is difficult to flow, and includes the pin insulator 1 for use in salt damage areas. The maintenance of distribution lines can be reduced. Moreover, since the outer peripheral surface of the protrusion 13 is finished to be a cylindrical surface, and the center axis thereof and the center axis of the metal fitting 20 are positioned on the same straight line, the accuracy of the mold during resin deposition is increased. Since it is held well, there is very little possibility that the protrusion 13 will be cracked or chipped by the pressing force of the mold, and it is possible to provide a insulator with good insulation.

  Next, a method for manufacturing the pin insulator 1 having the above-described configuration will be described in detail below.

  First, prior to forming the outer cover 30 by molding, the outer peripheral surface 13a of the protrusion 13 is previously polished using diamond abrasive grains so that the cross-sectional shape perpendicular to the central axis forms a perfect circle. Finish the cylinder surface and reduce its dimensional tolerance. Then, centering of the insulator body 10 and the metal fitting 20 is performed using a dedicated jig 50 as shown in FIG.

  As shown in the figure, the dedicated jig 50 includes a first base 52 for positioning the insulator body 10, a second base 54 for positioning the metal fitting 20, and a third base for positioning the arm mounting portion 24 extending from the metal fitting 20. The bases 52, 54, and 56 are relatively set in horizontal and vertical positions by a connecting rod 58. Specifically, at least the center axis of the through hole 52a of the first base 52 into which the protrusion 13 of the insulator body 10 is inserted and the center of the recess 54a of the second base 54 where the cup portion 22 of the metal fitting 20 is to be disposed. The bases 52 and 54 are set so that the axes are located on the same straight line.

  The metal fitting 20 is inserted into the through hole provided at the bottom center portion of the concave portion 54 a of the second base 54 to place the cup portion 22, and the tip portion of the arm attachment portion 24 is inserted into the concave portion 56 a of the third base 56. Thereby, the metal fitting 20 is positioned and held in a vertical state. The insulator body 10 is positioned with respect to the metal fitting 20 positioned and held by the second base 54 and the third base 56. That is, the insulator body 10 is inserted through the through hole 52 a of the first base 52, and the base portion 15 of the insulator body 10 is inserted into the metal fitting 20 and placed on the bottom portion 22 a of the cup portion 22.

  On the other hand, the protrusion 13 of the insulator body 10 is fitted into the through hole 52a of the first base 52 as shown in FIG. As a result, the insulator body 10 is positioned in an upright position relative to the metal fitting 20 so that the central axis of the protrusion 13 is positioned on the extension line of the central axis of the cup portion 22 of the metal fitting 20.

  Thus, when centering of the insulator body 10 and the metal fitting 20 is completed, by injecting an adhesive 40 such as cement between the base portion 15 of the insulator main body 10 and the cup portion 22 of the metal fitting 20, The insulator body 10 and the metal fitting 20 are joined and integrated.

  After the centering of the insulator body 10 and the metal fitting 20 is completed, the jacket body 30 is molded by molding into the joined and integrated insulator body 10 and the metal fitting 20 (hereinafter collectively referred to as the assembly body 2). Form. The mold is formed using a mold 60 as shown in FIG. 3, for example. The mold 60 shown in the figure has a half structure composed of a lower mold 62 and an upper mold 64, and the abutting surfaces 62a and 64a accommodate the assembly body 2 and a jacket to be molded. Cavities 66 and 68 for forming the body 30 are formed.

  According to such a mold 60, as shown in FIG. 4, when the assembly body 2 is disposed at a predetermined position of the cavity 66 of the lower mold 62, the cup body 22 of the metal fitting 20 is the base of the cavity 66. Positioned at the end, the top 14 of the body 10 is positioned at the tip of the cavity 66. Thus, the assembly body 2 is positioned at two locations of the cavity 66 of the lower mold 62.

  In particular, the top portion 14 of the insulator body 10, that is, the outer peripheral surface 13 a of the projection portion 13 of the wire mounting portion 16 is positioned at the tip end portion of the cavity 66. At this time, since the outer peripheral surface 13a of the protrusion 13 of the insulator body 10 is polished into a cylindrical surface in which the shape of the cross section perpendicular to the central axis is substantially a perfect circle, the body 10 is made of porcelain. Even if it exists, the dimensional tolerance in the outer peripheral surface 13a of the projection part 13 is small. As a result, the top portion 14 of the insulator body 10 is positioned and held with high accuracy by the lower mold 62.

  Prior to the molding of the mold, the centering of the insulator body 10 and the metal fitting 20 has been completed, so that the insulator body 10 is joined and integrated with the metal fitting 20 in an upright position at the center position. Yes. Therefore, the insulator body 10 is not tilted with respect to the metal fitting 20 and is set in the lower mold 62 in a posture standing upright at the center position, so that the top portion 14 of the insulator body 10 is positioned and held with higher accuracy by the lower mold 62. Is done. Of course, the same applies to the upper mold 64, and even when the molds 62 and 64 are brought together, they are held with high precision.

  In order to form the outer cover body 30 on a predetermined portion of the assembly body 2 using such molds 62 and 64, first, the assembly body 2 is provided with a portion of the outer peripheral surface 13a of the protrusion 13 from a part of the outer peripheral surface 13a. A predetermined amount of a plastic resin material 34 is wound around a part of the outer peripheral surface of the cup portion 22 and is attached. It is desirable that the deposition amount at this time be slightly larger than the space volume formed between the molds 62 and 64 when they are brought into contact with each other and the assembly body 2 is held in the cavities 66 and 68. At this time, in order to improve the adhesion between the assembly body 2 and the resin material 34, it is preferable to apply an adhesive (primer) to the outer peripheral surface of the assembly body 2 in advance. In this state, the assembly body 2 is placed in the cavity 66 of the lower mold 62 as shown in FIG. Then, the upper mold 64 (see FIG. 3) is brought into contact with the lower mold 62 and pressed. At this time, the operation of increasing the pressure force on the lower mold 62 and the upper mold 64 and then reducing it is repeated several times, and air is discharged from the molds 62, 64, thereby the mold 62. , 64 and the assembly body 2 are uniformly distributed, and the resin body 34 is molded into a shape regulated by the cavities 66 and 68 formed by both molds 62 and 64. An excessive amount of the resin body 34 is pushed out from a gap portion such as between the arm mounting portion 24 and the molds 62 and 64 or between the molds 62 and 64. As the resin material, rubber raw materials such as silicone rubber, modified silicone rubber, ethylene propylene rubber (EPR) or ethylene / vinyl acetate copolymer (EVA) can be used.

  By this press molding, the resin material 34 fills the space portion between the assembly body 2 and the inner walls of the cavities 66 and 68 of the molds 62 and 64 as shown in FIG. 6, and the outer peripheral surface of the assembly body 2, that is, A jacket body 30 is formed to adhere from the outer peripheral surface 13 a of the protrusion 13 of the insulator body 10 to the outer peripheral surface of the cup portion 22 of the metal fitting 20. Thereafter, the resin body 34 is heated to a predetermined temperature, and the resin body 34 molded into a predetermined shape is cross-linked to form an outer cover body 30. Then, after the assembly body 2 is taken out from the molds 62 and 64 as shown in FIG. 7, burrs (not shown) etc. of the outer cover body 30 are removed, thereby producing the pin insulator 1 shown in FIG. Is done. At this time, as described above, since the dimensional accuracy of the shape of the protruding portion 13 of the assembly body 2 and the central axis thereof and the central axis of the cup portion 22 of the metal fitting 20 are on the same straight line, The metal mold 64 and the lower metal mold 62 can be brought into close contact with the protruding portion 13 and the cup portion 22 of the metal fitting 20, so that resin leakage can be greatly reduced and the occurrence of burrs and the like can be suppressed.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. It includes the equivalent meanings recited in the claims and the equivalents recited in the claims, and all modifications within the scope.

It is a front view including the partial cross section which shows the pin insulator concerning this invention. It is a front view which shows the exclusive jig | tool for centering a insulator main body with respect to a metal fitting. It is a perspective view which shows the metal mold | die for forming a jacket body in an assembly body. FIG. 4 is a top view showing a setting state of the assembly body with respect to the lower mold of FIG. 3. It is a top view which shows the state which loaded the assembly body which wound the resin raw material in the lower metal mold | die. It is a top view which shows the state which removed the upper metal mold | die after forming the outer cover body in the assembly body. It is a front view which shows the state which took out the pin insulator which completed metal mold | die formation from the lower metal mold | die.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pin insulator 10 insulator main body 12 trunk | drum 13 protrusion part 13a outer peripheral surface of protrusion part 14 top part 15 base part 16 electric wire attachment part 20 metal fitting 30 outer covering 60 metal mold | die

Claims (3)

  It has a wire attachment part where the electric wire is fastened with a bind wire at the top, and a porcelain insulator body with a bottomed cup-shaped fitting fixed to the base part, and the lower part of the wire attachment part of the insulator body is larger than the trunk part The insulator body is a pin insulator having a diameter protrusion, and the center axis of the protrusion that has been polished so that the outer peripheral surface forms a cylindrical surface is positioned on the same straight line as the center axis of the metal fitting. And the metal fitting, and the insulator body and the metal fitting formed from the resin material having water repellency formed by die molding from the outer peripheral surface of the protrusion to the outer peripheral surface of the metal fitting. Pin insulator characterized by being coated.   It has a wire attachment part where the electric wire is fastened with a bind wire at the top, and a porcelain insulator body with a bottomed cup-shaped fitting fixed to the base part, and the lower part of the wire attachment part of the insulator body is larger than the trunk part A method of manufacturing a pin insulator having a diameter protrusion, wherein the outer peripheral surface of the protrusion of the wire mounting portion is polished into a cylindrical surface, and the center axis of the protrusion and the center axis of the metal fitting are the same straight line. After the insulator main body and the metal fitting are integrated so as to be positioned on a line, a resin material having water repellency is applied from the outer peripheral surface of the protruding portion of the insulator main body to the outer peripheral surface of the metal fitting. From the outer peripheral surface of the projection to the outer peripheral surface of the metal fitting, the insulator body is positioned and loaded into the mold, press-molded with the mold, and extended from the outer peripheral surface of the projection to the outer peripheral surface of the metal fitting. The sheath body covering the insulator body and the metal fitting is formed. Method for producing a pin insulators, characterized by.   After polishing the outer peripheral surface of the protruding portion into a cylindrical surface, the insulator main body is joined and integrated in an upright posture so as to share the central axis with the metal fitting, and then the outer peripheral surface of the protruding portion The manufacturing method of the pin insulator of Claim 2 which positions the said insulator main body in the said metal mold | die with the outer peripheral surface of the said metal fitting.

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