JP4477374B2 - Cold shrink tube and manufacturing method thereof - Google Patents

Description

  The present invention relates to a cold shrink tube and a method for producing the same.

  Conventionally, a cold-shrinkable tube made of rubber or the like is known as an insulating covering member for an electric wire connecting portion. This room temperature shrinkable tube is expanded by a diameter-expandable member that can be disassembled, and is placed on the outer periphery of the wire connection portion in the expanded state. It is used in close contact with the outer periphery of the part. (See Patent Document 1)

JP-A-9-306566

  As described above, since the cold-shrinkable tube is expanded in diameter by the diameter-expanding member, stress acts on the cold-shrinkable tube in the circumferential direction.

By the way, the cold shrinkable tube is manufactured as shown in FIGS.
5A and 5B, 1 is a cored bar, 2 is a main mold, and 3 is a cylindrical space. The cored bar 1 is cylindrical. The main mold 2 has a cylindrical groove 4 formed on the inner peripheral surface and is divided into two in the longitudinal direction. When the main die 2 divided in half in the longitudinal direction is put on the outer periphery of the cylindrical metal core 1, a cylindrical space 3 is formed between the metal core 1 and the main die 2. A material is injected into the cylindrical space 3 from an injection hole (not shown) formed in the main mold 2 to form a cold shrink tube. Thereafter, by removing the main mold 2, a cold shrinkable tube can be manufactured.

  The normal temperature shrinkable tube 10 manufactured as described above is expanded in diameter by a diameter-expandable member 11 that can be disassembled, as shown in FIGS. The diameter-expanding member 11 is a cylindrical member in which, for example, a plastic string is wound in a spiral shape and the adjacent end portions are spot-welded, the end portion on one end side is led out to the other end side through the inside, and the lead-out portion is It can be easily disassembled by pulling.

By the way, the normal temperature shrinkable tube 10 manufactured as described above has a mold joint 13 in the longitudinal direction and both end faces of the outer periphery as shown in FIGS. Material overflow occurs. Since it is undesirable to have overflow in the product, overflow is usually removed.
However, it can damage the product in removing the overflow. When the product is damaged in this way, there is a problem that when the diameter of the product is increased, the damaged portion becomes a defect and tearing occurs.
In particular, when the diameter of the cold shrinkable tube 10 is increased, the maximum stress position is the position of the inner peripheral portion A of both end faces, and there is a problem that tearing is likely to occur if the position is damaged.

  This invention is made | formed in view of the said problem, and it aims at providing the normal temperature shrinkable tube which does not produce a tear when it expands in diameter.

In order to achieve the above object, the invention described in claim 1 of the present invention is characterized in that there is no joint of the mold at the inner peripheral position of both end faces, and the room temperature shrinkage for covering the wire connection part It is a tube.

According to a second aspect of the present invention, there is provided a mold composed of a cored bar and a main mold, and a cylindrical space is provided between the cored bar and the main mold by covering the outer periphery of the cored bar with the main mold. part is formed, in the manufacturing method of coating Coldshrink of the wire connection portion by injecting material from the injection holes formed in the main mold in the cylindrical space to produce a cold-shrink tube covering the wire connection portion Manufacturing the cold-shrinkable tube for covering the wire connecting portion by combining the core metal and the main mold so that the joint between the core metal and the main mold does not exist at the inner peripheral position of the both end faces of the cylindrical space portion. It is the manufacturing method of the normal temperature shrinkable tube for coating | covering the electric wire connection part characterized. The cylindrical space portion has a cylindrical groove on the outer peripheral surface and is divided into two in a direction perpendicular to the longitudinal direction and a main mold divided in two in the longitudinal direction. It may be a cylindrical space portion formed by covering the outer periphery of the cored bar assembled with the cored die, and recessed portions are formed at both ends of the groove. Is formed at both ends of the core metal and is small at the middle side, and the cylindrical space portion is formed by covering the outer periphery of the core metal assembled from the core metal divided into two parts with the main mold. Part.

  According to the cold-shrinkable tube described in claim 1 of the present invention, there is no mold seam at the inner peripheral position of both end faces, so that overflow does not occur at this position, and this position is damaged. Never give. Therefore, it is possible to obtain a cold-shrinkable tube that does not tear even when the diameter is increased.

  As in the method for manufacturing a cold-shrinkable tube according to claim 2 of the present invention, the cored bar and the main mold are arranged so that there is no joint between the cored bar and the main mold at the positions of the inner peripheral portions of both end faces of the cylindrical space. When a cold shrinkable tube is manufactured by combining the molds, a cold shrinkable tube can be easily obtained in which there is no mold joint at the positions of the inner peripheral portions of both end faces.

Next, embodiments of the present invention will be described in detail with reference to the drawings.
FIGS. 1 (a) and 1 (b) show a mold used for producing a cold-shrinkable tube according to the present invention, wherein 1 is a cored bar, 2 is a main mold, and 3 is a cylindrical space.

  The cored bar 1 has a cylindrical groove 4 formed on the outer peripheral surface thereof. Further, the core metal 1 is divided into two parts in a direction orthogonal to the longitudinal direction, and the divided pieces 1A and 1B are abutted and assembled.

  The main mold 2 is divided into two in the longitudinal direction, and the inner diameter thereof is formed to be equal to the outer diameter of the cored bar 1.

  When the main die 2 divided into two in the longitudinal direction is put on the outer periphery of the core metal 1 assembled by abutting the divided pieces 1A and 1B, a cylindrical space 3 is formed between the core metal 1 and the main die 2. Is done.

  In the mold assembled in this way, the joint between the core metal 1 and the main mold 2 does not exist at the inner peripheral position A on both end faces of the cylindrical space.

  In order to manufacture a cold shrink tube using the mold assembled as described above, a material such as silicon rubber is injected into the cylindrical space portion 3 from an injection hole (not shown) formed in the main mold 2. Mold a cold shrink tube. Thereafter, the main mold 2 is removed and the core metal 1 is removed. Thereby, a cylindrical cold-shrinkable tube can be manufactured.

  As shown in FIGS. 2A and 2B, the normal temperature shrinkable tube 10 manufactured in this way has a mold seam in the longitudinal direction of the outer periphery of the normal temperature shrinkable tube 10, but the inner periphery of both end faces. There is no part A. Therefore, there is no overflow at the position, and this does not damage the position. For this reason, as shown in FIGS. 2A and 2B, even if the diameter of the diameter-expanding member 11 is increased, it does not tear from the inner peripheral position A on both end faces of the cold-shrinkable tube 10.

  The diameter-expanding member 11 is formed by, for example, winding a plastic string in a spiral shape and spot-welding the adjacent side end portion into a cylindrical shape. It can be easily disassembled by pulling the part that has been pulled.

FIGS. 3 (a) and 3 (b) show another embodiment of a mold used for producing a cold shrinkable tube according to the present invention. The same parts as those in the above embodiment are denoted by the same reference numerals.
This mold is the same as the mold of the above embodiment in that the core metal 1, the main mold 2, and the cylindrical space 3 are provided, but the position of the cylindrical space 3 is the same as that of the above embodiment. It is different.
That is, the cylindrical space portion 3 formed on the outer periphery of the cored bar 1 has a shape in which both end sides thereof are positioned in the recesses 7 formed on both sides of the cored bar 1.
On the other hand, the main mold 2 is divided in half in the longitudinal direction, and the inner diameter is large at both ends and small at the middle.

  When the main die 2 divided in the longitudinal direction is put on the outer periphery of the cored bar 1 assembled by abutting the divided pieces 1A and 1B, a cylindrical space 3 is formed between the cored bar 1 and the main mold 2. Is done.

  The mold assembled in this way has an inner peripheral portion position A on both end faces of the cylindrical space portion located in the core metal 1, so that the core is positioned on the inner peripheral portion position A on both end faces of the cylindrical space portion. There is no joint between the gold 1 and the main mold 2.

  In order to manufacture a cold shrink tube using the mold assembled as described above, a material such as silicon rubber is injected into the cylindrical space portion 3 from an injection hole (not shown) formed in the main mold 2. Mold a cold shrink tube. Thereafter, the main mold 2 is removed and the core metal 1 is removed. Thereby, a cylindrical cold-shrinkable tube can be manufactured.

  As shown in FIGS. 4A and 4B, the cold shrinkable tube 10 manufactured in this way does not have a die joint at the inner peripheral portion position A of both end faces. Therefore, there is no overflow at the position, and this does not damage the position. For this reason, as shown in FIGS. 4A and 4B, even if the diameter of the diameter-expanding member 11 is increased, it does not tear from the inner peripheral position A of the both end faces of the cold shrink tube 10.

  In addition, the cold shrinkable tube 10 manufactured as described above has no mold joints at the outer peripheral portion positions B of both end faces. Therefore, there is no overflow at the position, and this does not damage the position. Therefore, as shown in FIGS. 4 (A) and 4 (B), there is an effect that even if the diameter is increased by the diameter-expanding member 11, it is not torn from the outer peripheral portion positions B on both end faces of the cold-shrinkable tube.

  The diameter-expanding member 11 is formed by, for example, winding a plastic string in a spiral shape and spot-welding the adjacent side end portion. The end portion on one end side is led out to the other end side through the inside and pulled out. The point that it can be easily disassembled is the same as in the above embodiment.

  In addition, the metal mold | die used by this invention is not limited to the thing of the said embodiment, When the metal core and the main mold are combined, the metal core is located at the inner peripheral portion of both end faces of the cylindrical space portion. The shape of the mold is not particularly limited as long as it does not have a joint between the main mold and the main mold.

(A) is a half sectional view of a mold used in the present invention, (B) is a sectional view taken along line AA in (A). (A) is a half cross-sectional view showing an expanded state of a normal temperature shrinkable tube according to the present invention, and (b) is a side view of (b). (A) is a half cross-sectional view showing another embodiment of a mold used in the present invention, and (b) is a cross-sectional view taken along line AA of (a). (A) is a half cross-sectional view showing an expanded state of a normal temperature shrinkable tube according to the present invention, and (b) is a side view of (b). (A) is a half sectional view of a conventional mold, (B) is a sectional view taken along line AA in (A). (A) is a half cross-sectional view showing a diameter expansion state of a conventional cold shrink tube, and (b) is a side view of (b).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Core metal 1A / 1B Division | segmentation piece 2 Main mold 3 Cylindrical space 4 Cylindrical groove 7 Recessed part 10 Room temperature shrinkable tube 11 Diameter expansion member

Claims (4)

A room-temperature-shrinkable tube for covering a wire connection portion, characterized in that there is no die joint at the inner peripheral position of both end faces. Comprising a mold made up of a core metal and a main mold, covered with a primary mold to the outer periphery of the core metal to form a cylindrical space between the metal core and the master mold, in the main type the cylindrical space in the formation process for the preparation from the injection holes to inject the material for coating cold-shrink tube of the wire connecting portion to produce a coating Coldshrink of the wire connecting portion, the inner peripheral portion position of the end surfaces of the cylindrical space preparation of the core and the main type of seam by combining metal core and the main mold such that there is the wire connecting portion for covering cold shrinkable tube, characterized in that to produce a cold-shrink tube covering the wire connection portion to Method. The cylindrical space portion has a cylindrical groove on the outer peripheral surface and is divided into two in a direction perpendicular to the longitudinal direction and a main mold divided in two in the longitudinal direction. The manufacture of the cold-shrinkable tube for covering an electric wire connection part according to claim 2, wherein the outer periphery of the cored bar assembled with the cored bar is a cylindrical space part formed by covering the main mold. Method. Concave portions are formed at both ends of the groove, the main mold is formed at both ends of the core bar to be large at the middle side and small at the middle side, and the cylindrical space part is assembled into two parts of the core metal 4. The method of manufacturing a cold-shrinkable tube for covering a wire connecting portion according to claim 3, wherein the outer periphery of the cored bar is a cylindrical space formed by covering the main mold.

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