JP2000067677A - Compression molding method for composite insulator and forming die used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compression molding method for a composite insulator capable of reducing material loss, shortening a cleaning time for a forming die, eliminating residual foams and avoiding chronic defectives, and a forming die used therefor. SOLUTION: In a compression molding method for a composite insulator for compression molding a covering for the composite insulator including a core member and the covering having a body provided on the outer periphery of the core member and a plurality of shades by using a forming die 21 having a male mold 22 and a female mold 23, the covering for the composite insulator is compression molded (1) in the condition that a chamber 29 is evacuated which has a structure of holding the male mold and the female mold inside in air tightness, (2) in the condition that flow-out resistance is given to molded material attempted to flow out of a mating face between the male mold and the female mold, when mating each other, by a discharge restricting plate 26 provided on the mating face between the male mold and the female mold, and (3) in the conditions of the above (1), (2).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite insulator comprising a core member and a shell comprising a body and a plurality of caps provided on the outer periphery of the core member. The present invention relates to a method for compression-molding a composite insulator, which is compression-molded using a mold comprising: In the present invention, the term "composite insulator" is used as a concept including both a polymer insulator having a solid core member and a lightning arrester having a hollow core member.

[0002]

2. Description of the Related Art Conventionally, various types of composite insulators comprising a core member and a shell provided on the outer periphery of the core member and comprising a plurality of caps are known. In manufacturing such a composite insulator, a compression molding method is often used when molding a jacket made of rubber.

FIGS. 13 to 15 are diagrams for sequentially explaining an example of a conventional method of compression molding a composite insulator. 13 to 15 show, as an example of a composite insulator, an example in which a core member is formed by compression molding a jacket of a solid polymer insulator. In the example shown in FIGS.
Is an upper mold, 52 is a lower mold, 53 is an FRP rod as a core member of a polymer insulator, 54 is a jacket molding material made of, for example, silicone rubber wound around the FRP rod 53 in advance, and 55 is an upper mold 51 and a lower mold. It is a cavity for molding a jacket provided in the mold 52.

[0004] A conventional compression molding method for a composite insulator will be described with reference to FIGS. 13 to 15. First, as shown in FIG. 13, a pre-pressed mold 51 and a lower mold 52 are heated to a predetermined temperature. FRP rod 53 wound with jacket molding material 54
Is set. Next, as shown in FIG. 14, the upper mold 51 and the lower mold 52 are closed, the molding material 54 is filled in the cavity 55, and the molding material 5 is held in this state.
Vulcanization of No. 4 proceeds. Hold molding material 5 for a certain period of time
After the vulcanization of No. 4 is completed, as shown in FIG.
2 is lowered to release the upper mold 51 from the lower mold 52, whereby the compression molding of the polymer insulator is completed and the FRP rod 5
A jacket 56 can be formed around the periphery of the third member 3.

[0005]

According to the above-described conventional method for compressing and molding a composite insulator, the sheath molding material 54 is compressed and penetrates to the tip of the cavity 55 having a complicated shade shape. At the same time, as shown in FIG.
The outer molding material 54 is caused to flow out of the mold through the mating surface 57, thereby giving outflow resistance to the outer molding material 54,
It was necessary to fill the molding material 54 to the tip of the cavity 55. Therefore, there is a problem that the loss of the expensive outer molding material 54 increases, and the time for cleaning the outer molding material 54 attached to the mold becomes longer, so that the cost of the polymer insulator as a product cannot be reduced. . Further, in the compression molding method, there is also a problem that air bubbles are caught in the envelope molding material 54 at the time of the compression molding, and a chronic failure that the envelope 56 having good electric characteristics cannot be formed occurs. In order to eliminate the entrapment of air bubbles, bumping is performed in which the upper mold 51 and the lower mold 52 are opened a plurality of times to discharge air bubbles to the outside. However, this bumping also has a limit of air bubble removal, and still has sufficient electric characteristics. There was also a problem that it was not possible to obtain a polymer insulator having a jacket 53 having the following.

An object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide a method of compression-molding a composite insulator which can reduce material loss, shorten a mold cleaning time, eliminate bubbles, and prevent chronic failure, and a mold used therefor.

[0007]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method for compressing and molding a composite insulator, comprising the steps of: forming a composite insulator comprising a core member, a shell provided on the outer periphery of the core member and a plurality of caps; In a compression molding method of a composite insulator, in which a jacket is compression-molded by using a mold composed of an upper mold and a lower mold, (1) a chamber having a structure capable of keeping the upper mold and the lower mold airtight inside the mold. And with the chamber degassed,
(2) The discharge suppressing plate provided on the mating surface of the upper mold and the lower mold gives outflow resistance to the molding material flowing out from the mating surface of the upper mold and the lower mold when the upper mold and the lower mold are joined. (3) A chamber having a structure capable of keeping the upper mold and the lower mold airtight inside is provided integrally with the mold, and the chamber is evacuated and the upper mold and the lower mold are combined. The discharge suppression plate provided on the surface compresses the outer cover of the composite insulator while giving outflow resistance to the molding material flowing out from the mating surface of the upper and lower dies when the upper and lower dies are fitted It is characterized by being molded.

The mold used in the method for compressing and molding a composite insulator according to the present invention is a mold used for the method for compressing and molding a composite insulator, and is provided integrally around each of an upper mold and a lower mold.
When the upper mold and the lower mold are provided together with the upper mold chamber and the lower mold chamber, and / or the upper mold and the lower mold are provided on the mating surface of the upper mold and the lower mold. The present invention is characterized by having a discharge suppressing plate for giving outflow resistance to a molding material flowing out from a mating surface of an upper die and a lower die.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a composite insulator to which the compression molding method of the present invention is applied will be described. 1 and 2 are diagrams showing an example of the composite insulator of the present invention. FIG. 1 shows an example of a polymer insulator, and FIG. 2 shows an example of a lightning arrester. The polymer insulator 1 shown in FIG. 1 includes a solid FRP rod 2 as a core member and a jacket 3 made of, for example, silicone rubber provided on the outer periphery of the FRP rod 2. The outer cover 3 includes a body 4 and a plurality of caps 5 protruding from the body 4. The lightning arrester 11 shown in FIG. 2 includes a hollow FRP cylinder 12 as a core member,
An outer casing 13 made of, for example, silicone rubber is provided on the outer periphery of the FRP cylinder 12. The outer cover 13 is composed of a trunk 14 and a plurality of caps 15 protruding from the trunk 14, and the caps 15 have a large diameter cap and a small diameter cap alternately arranged. A plurality of zinc oxide elements (not shown) are inserted into the FRP cylinder 12.

Next, a method of manufacturing the polymer insulator 1 shown in FIG. 1 and the lightning arrester insulator 11 shown in FIG. 2 will be described. FIG. 3 is a flowchart showing an example of a method for manufacturing the polymer insulator 1. The method of manufacturing the polymer insulator 1 will be described with reference to FIG. 3. First, the FRP rod 2 is sandblasted to roughen the surface. Next, a primer is applied to the roughened surface of the FRP rod 2 and then dried. Next, a cylindrical rubber is molded around the FRP rod 2 by a rubber extruder to obtain a preformed body in which the cylindrical rubber is set on the outer periphery of the FRP rod 2 in advance. Next, if necessary, the preformed body is preheated at, for example, 90 ° C. for 60 minutes, and the preheated preformed body is compression-molded using a mold to obtain a formed body. Vulcanization at the time of molding is, for example, 160 ° C., 25
And vulcanizing at a predetermined pressure during vulcanization. Next, the molded body is released from the mold, finishing such as removal of burrs is performed, metal fittings are gripped at both ends of the FRP rod 2, and a sealant is provided at a joint between the metal fitting and the FRP rod 2 at the metal fitting end. The polymer insulator 1 is obtained. Needless to say, at the stage of the preform, a fitting may be obtained by previously holding metal fittings at both ends of the FRP rod 2 and compression molding the preformed body holding the metal fitting.

FIG. 4 is a flowchart of an example of a method for manufacturing the lightning arrester 11. The method of manufacturing the lightning arrester 11 will be described with reference to FIG. 4. First, similarly to the above-described method of manufacturing the polymer insulator 1, the surface of the FRP tube 12 is roughened, and then a primer is applied. Next, for example, at 165 ° C.
The pre-heated FRP cylinder 12 is set in the above, and the rubber provided above and below the FRP cylinder 12 is compression molded to obtain a molded body. For vulcanization during molding, vulcanization is performed, for example, at 165 ° C. for 15 minutes, and bumping is performed at a predetermined pressure during vulcanization. Next, the compact is released from the mold, finishing such as removal of burrs is performed, and then secondary vulcanization is performed as necessary. The secondary vulcanization is, for example, 150 ° C.,
It is a condition of time. Next, a zinc oxide element, a spring, or the like is inserted into the inside of the FRP cylinder 12, and a metal fitting is gripped at both ends of the FRP cylinder 12. Liquid rubber is pressed into an internal gap to seal both ends, so that the final lightning arrester 11 Get.

The present invention relates to a method of manufacturing the above-described polymer insulator 1 and a compression molding method in the method of manufacturing the lightning arrester 11. That is, (1) a chamber having a structure capable of keeping the upper mold and the lower mold airtight inside is provided integrally with the mold, and compression molding is performed in a state where the inside of the chamber is evacuated;
(2) The discharge suppressing plate provided on the mating surface of the upper mold and the lower mold gives outflow resistance to the molding material flowing out from the mating surface of the upper mold and the lower mold when the upper mold and the lower mold are joined. Or (3) a chamber having a structure capable of keeping the upper mold and the lower mold airtight inside is provided integrally with the mold,
With the inside of this chamber being evacuated, and by the discharge suppressing plate provided on the mating surface of the upper mold and the lower mold, when the upper mold and the lower mold are joined, they will flow out of the mating surface of the upper mold and the lower mold. In a state where the outflow resistance is given to the molding material to be formed, the jacket of the composite insulator is compression-molded.

In the present invention, the compression molding is preferably performed in a chamber evacuated to a state close to a vacuum, so that the entrapment of air bubbles during the compression molding can be remarkably reduced, and a chronic defect caused by the entrapment of air bubbles is eliminated. be able to. In addition, by forming the discharge suppressing plate in the mold and performing compression molding, the amount of rubber flowing out from between the upper mold and the lower mold can be significantly reduced, and material loss can be reduced. Since the amount of rubber remaining between the upper mold and the lower mold is also reduced, the time for cleaning the mold can be shortened.

FIGS. 5 to 8 are views for explaining an example of a mold used in the method of compression-molding a composite insulator according to the present invention. Here, FIG. 5 is a plan view of the lower mold constituting the mold as viewed from above,
FIG. 6 is a front view showing an upper mold and a lower mold that constitute the mold (however, some members are omitted for easy understanding of the upper mold and the lower mold), and FIG. 7 is shown in FIG. Side view of upper and lower molds,
FIG. 8 is a view showing a state where the upper mold and the lower mold are closed in the side view shown in FIG. In the example shown in FIGS.
1 is a mold, 22 is an upper mold that constitutes the mold 21, 23 is a lower mold that constitutes the mold 21, and 24 is a mating surface 22a of the upper mold 22 provided integrally with the entire periphery of the upper mold 22. An upper mold chamber portion protruding downward, 25 is a lower mold chamber portion integrally provided around the entire periphery of the lower mold 23 and protruding above the mating surface 23a of the lower mold 23, 26 are both longitudinal sides of the lower mold 23 A pair of discharge suppression plates protruding from the mating surface 23a on each surface, 27 is a discharge suppression plate storage portion for accommodating the discharge suppression plate 26 provided on both longitudinal sides of the upper mold 22, and 28 is an upper mold 21. With the lower mold 22 closed and a vacuum device attached, the gas in the chamber 29 formed by the upper mold chamber 25 and the lower mold chamber 26 is sucked to make the inside of the chamber 29 preferably a substantially vacuum degassed state. Mouth.

Each of the upper mold 22 and the lower mold 23 has a structure in which a plurality of segments 31 are integrally stacked, and has a cavity 32 for molding a jacket comprising a body and a plurality of caps. . Therefore, by increasing or decreasing the number of segments 31 according to the length, in other words, the number of segments of the composite insulator to be formed, it is possible to cope with a change in the number of shades of the composite insulator to be formed. In the mold 21 of the present invention,
As described above, when the number of shades of the composite insulator to be formed is changed, not only is the number of the segments 31 changed to adjust the lengths of the upper mold 22 and the lower mold 23, but also to form the upper mold chamber 24 and the lower mold chamber. The part 25 is also configured to be able to change its length accordingly. That is, the upper mold chamber 2
4 and the lower mold chamber 25 are provided with connecting portions 24b and 25b, and a block (not shown) is added to these connecting portions 24b and 25b to adjust the lengths of the upper mold chamber 24 and the lower mold chamber 25. be able to. As shown in FIG. 5 to FIG. 8, the inner peripheral surface 24 a of the upper mold chamber 24 and the outer peripheral surface 25 a of the lower mold chamber 25 are
An O-ring 33 provided over the entire outer periphery of the inner peripheral portion of the device makes it slidable in an airtight state. With this configuration, the upper mold 22 and the lower mold 23 can be held airtight inside.

When the upper mold 22 and the lower mold 23 are closed, a pair of discharge suppressing plates 26 provided on the lower mold 23 are connected to the upper mold 2.
2 is housed in the discharge suppression plate housing section 27 provided in the second embodiment. At this time, the outer peripheral surface 26a facing the center of each of the discharge suppressing plates 26 and the inner peripheral surface 27a facing the center of the discharge suppressing plate storage portion 27 are kept almost in contact with each other. By providing the discharge suppressing plate 26, when the upper die 22 and the lower die 23 are fitted, the upper die 2
An outflow resistance is given to the outer molding material flowing out from the mating surface (22a, 23a) of the lower mold 23 and the lower mold 23, and the outer molding material can be efficiently and reliably filled into the cavity 32 of the mold. . This outflow resistance is determined by the upper mold 22 and the lower mold 23.
Is generated when the outer peripheral surface 26a of the discharge suppressing plate 26 and the inner peripheral surface 27a of the discharge suppressing plate housing portion 27 overlap and start to contact with each other.
The maximum value is obtained immediately before the contact between 2a and 23a. Due to this outflow resistance, the envelope molding material has an internal pressure toward the inside of the mold 21. On the other hand, the excess jacket molding material has an outflow resistance to give an internal pressure thereto, and passes through a narrow gap formed when the discharge suppression plate 26 and the discharge suppression plate storage portion 27 are fitted to the jacket molding material reservoir 30. Be guided. Therefore, the amount of the jacket molding material flowing out of the mold 21 can be significantly reduced as compared with the conventional mold.

Next, the compression molding method of the composite insulator of the present invention using the above-described mold 21 will be further described with reference to FIGS. In this example, a compression molding method of the lightning arrester 41 will be described as an example. First, FIGS. 9 and 10
As shown in the figure, the upper mold 22 and the lower mold 23 are opened, and the upper mold 22 is opened.
An FRP cylinder 42 and an outer molding material 43 such as silicone rubber are set between the lower mold 23 and the lower mold 23. In the example shown in FIG. 9, the envelope molding material 43 is provided in a cylindrical shape around the FRP cylinder 42 in advance. In the example shown in FIG. 10, two plate-shaped jacket molding materials 43 are provided above and below the FRP cylinder 42. FRP
The setting of the cylinder 42 is performed by supporting the FRP cylinder 42 with support portions 44 provided at both ends in the longitudinal direction of the lower mold 23.

Next, as shown in FIG. 11, the upper mold 22 and the lower mold 23 are closed, the outer molding material 43 is filled in the outer cavity, and the outer molding material filled in the cavity is filled. 43 is vulcanized. At this time, the upper mold 22 and the lower mold 2
3 from the set state shown in FIG. 9 or FIG. 10 to the closed state shown in FIG.
A vacuum device (not shown) connected to
The inside gas is sucked to make the inside of the chamber 29 a substantially vacuum degassed state. Thereafter, the suction from the vacuum device is stopped, and the upper mold 22 and the lower mold 23 are opened and separated from each other, so that a predetermined molded body of the lightning arrester 41 can be obtained as shown in FIG.

In the above-described embodiment, the lightning arrester and the polymer insulator have been described as examples of the composite insulator. However, the present invention is preferably applied to other insulators and composite insulators in which the jacket is compression-molded. It goes without saying that you can do it. In addition, although the vacuum device mounting port 28 is used to evacuate the inside of the chamber, it can be said that any other method can be used as long as there is a means for making the inside of the chamber substantially evacuated during compression molding. Not even.

[0020]

As is apparent from the above description, according to the present invention, it is possible to significantly reduce the entrapment of air bubbles during compression molding by performing compression molding in a chamber that is preferably evacuated to a state close to vacuum. Thus, chronic defects caused by entrainment of air bubbles can be eliminated. In addition, by forming the discharge suppressing plate in the mold and performing compression molding, the amount of rubber flowing out from between the upper mold and the lower mold can be significantly reduced, and material loss can be reduced. ,
Since the amount of rubber remaining between the upper mold and the lower mold is also reduced, the mold cleaning time can be shortened.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a polymer insulator as an example of a composite insulator to which the present invention is applied.

FIG. 2 is a diagram showing an example of a lightning arrester as another example of the composite insulator to which the present invention is applied.

FIG. 3 is a flowchart illustrating a method for manufacturing a polymer insulator.

FIG. 4 is a flowchart illustrating a method for manufacturing a lightning arrester.

FIG. 5 is a diagram for explaining an example of a mold used in the method of compression-molding a composite insulator according to the present invention.

FIG. 6 is a front view showing an upper mold and a lower mold constituting a mold used in the present invention.

FIG. 7 is a side view of the upper die and the lower die shown in FIG.

8 is a diagram showing a state where an upper mold and a lower mold are closed in the side view shown in FIG. 7;

FIG. 9 is a view for explaining one step of the compression molding method of the composite insulator of the present invention.

FIG. 10 is a view for explaining another step of the compression molding method of the composite insulator of the present invention.

FIG. 11 is a view for explaining still another step of the compression molding method of the composite insulator of the present invention.

FIG. 12 is a view for explaining still another step of the compression molding method of the composite insulator of the present invention.

FIG. 13 is a view for explaining one step of a conventional compression molding method for a composite insulator.

FIG. 14 is a view for explaining another step of the conventional composite insulator compression molding method.

FIG. 15 is a view for explaining still another step of the conventional composite insulator compression molding method.

[Explanation of symbols]

Reference Signs List 1 polymer insulator, 2 FRP rod, 3, 13 jacket, 4, 14 trunk, 5, 15 shade, 11, 41 lightning arrester, 12, 42 FRP cylinder, 21 mold, 22 upper mold,
22a, 23a Mating surface, 23 Lower mold, 24 Upper mold chamber, 24a, 27a Inner peripheral surface, 24a, 25a
Connecting portion, 25 lower mold chamber portion, 25a, 26a outer peripheral surface, 26 discharge suppression plate, 27 discharge suppression plate storage portion, 28
Vacuum installation port, 29 chambers, 30 casing material pool, 31 segments, 32 cavities,
33 O-ring, 43 Jacket molding material, 44 Support

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5G331 AA02 AA03 AA06 AA07 BB31 CA05 CA06 5G333 AA11 AB01 AB05 AB28 BA01 CB17 CC18

Claims (5)

[Claims] 1. A composite insulator comprising a core member, a shell provided on the outer periphery of the core member and a plurality of caps, and a mold comprising an upper mold and a lower mold. In the compression molding method of a composite insulator to be compression-molded by using, a chamber having a structure capable of keeping an upper mold and a lower mold airtight inside is provided integrally with a mold, and the inside of the chamber is evacuated and the outside of the composite insulator is removed. A method for compression-molding a composite insulator, which comprises compression-molding a jacket. 2. A composite insulator jacket comprising a core member and a shell provided on the outer periphery of the core member and comprising a plurality of caps, a mold comprising an upper mold and a lower mold. In the compression molding method for composite insulators that are used for compression molding, the discharge suppression plate provided on the mating surface of the upper and lower dies allows the upper and lower dies to be joined together when the upper and lower dies are joined. A compression molding method for a composite insulator, comprising compressing and molding a jacket of the composite insulator in a state in which the molding material to be discharged is given outflow resistance. 3. A composite insulator made up of a core member and a shell provided on the outer periphery of the core member and composed of a plurality of caps, is molded into an upper mold and a lower mold. In the method for compressing and molding a composite insulator by use, a chamber having a structure capable of keeping an upper mold and a lower mold airtight is provided integrally with a mold, and the inside of the chamber is evacuated, and With the discharge suppression plate provided on the mating surface of the mold and the lower mold, with the outflow resistance given to the molding material flowing out from the mating surface of the upper mold and the lower mold when the upper mold and the lower mold are fitted, A compression molding method for a composite insulator, which comprises compression-molding a jacket of the composite insulator. 4. A mold for use in the method of compression-molding a composite insulator according to claim 1, wherein the upper mold and the lower mold are provided integrally around respective upper and lower molds. The upper mold chamber and the lower mold chamber, which are configured to be able to maintain the airtightness between the upper mold and the lower mold, and / or the upper mold provided on the mating surface of the upper mold and the lower mold when the upper mold and the lower mold are fitted. A mold having a discharge suppressing plate for giving a flow resistance to a molding material flowing out from a mating surface of the mold and the lower mold. 5. The method according to claim 1, wherein the upper chamber section or the lower chamber section includes:
5. The mold according to claim 4, further comprising a vacuum device mounting port for sucking a gas in the chamber formed by the upper mold chamber and the lower mold chamber to evacuate the chamber.