JP2002059481A - Device for expanding diameter of cold-shrinkable tube and method of expanding diameter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diameter expanding apparatus which can uniformly expand the diameter of a room-temperature shrinkable tube without damaging the inside thereof, reduce the burden on an operator, and have good workability, and a method of expanding the diameter by the apparatus. SOLUTION: A diameter-expanding device 1 includes a diameter-expanding mechanism 2 for radially moving a plurality of rods 8 inserted into a cold-shrinkable tube to expand the tube larger than an outer diameter of a core.
Equipped. The diameter expanding mechanism 2 includes a grip 41 of the rod 8, a slider 42 that moves the grip 41 forward and backward, and a slide holder 43 that supports the slider 42.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diameter-expanding apparatus and a method for expanding the diameter of a cold-shrinkable tube for inserting a core into the tube.

[0002]

2. Description of the Related Art Waterproofing, insulation, mechanical protection, and the like are required for a cable connection portion such as a connection between cables or a connection between a cable and a terminal device. As these protections,
There is a method in which a waterproof tape or an insulating tape is wound around the cable connection portion, or a heat-shrinkable tube is used which contracts by using a heating means such as a burner. However, the former tape protection involves variations in performance depending on the skill of the worker, and also requires a long working time. In the latter case, when a heat-shrinkable tube is used, workability is poor because heat treatment is required.

[0003] In order to improve the workability, there is a method using a cold shrinkable tube having self-shrinkage as shown in FIG. In this method, a cold-shrinkable tube that has been previously formed into a shape compatible with the connection portion of the cable is expanded in diameter, and placed in the connection portion, and then the expanded portion of the tube is opened to release the connection portion by self-shrinking force. The same tube is attached to this. In this method, as shown in FIG. 7 in which a cylindrical core, for example, a core disclosed in Japanese Utility Model Publication No. 2-1816 is inserted into the cold-shrinkable tube which has been previously expanded to maintain the expanded state of the cold-shrinkable tube. Molded products are used. After the molded article is placed at the cable connection portion, the core is removed to release the expanded state of the cold shrink tube, and the tube is attached along the outer peripheral surface of the cable connection portion.

As a method of expanding the diameter of a cold-shrinkable tube in order to form the molded article, for example, Japanese Patent Application Laid-Open No. H10-337778
There is an invention disclosed in Japanese Patent Publication No. According to the present invention, a rotating roll and a moving rotating roll fixed to the apparatus are inserted into the cold shrink tube, and the rotating roll is rotated along the inner circumference of the cold shrink tube. At the same time, this method is to expand the diameter of the cold shrinkable tube in the circumferential direction by moving the movable rotating roll in parallel.

[0005]

However, when the diameter of the cold-shrinkable tube is increased by a small number (two) of rotating rolls as described in the above invention, workability is extremely deteriorated due to the following problems. . It is extremely difficult to insert a plurality of rotating rolls into a cold shrink tube before diameter expansion. If a small number of rotating rolls are used to obtain an expanding force corresponding to the self-shrinking force of the cold shrink tube, the diameter of each rotating roll must be increased. However, it is extremely difficult to insert a rotating roll having a large diameter into a cold shrink tube. In particular, in the case of a cold-shrinkable tube having a small inner diameter before diameter expansion, the difficulty of insertion becomes significant.

When expanding the diameter, it is difficult to uniformly expand the diameter of the room-temperature shrinkable tube. When using a small number of rotating rolls,
The cold-shrinkable tube is partially stretched and not uniformly expanded in diameter, and a large difference in the stretched state is formed between a portion near the rotating roll and a portion near the rotating roll. For this reason, distortion occurs inside the cold shrinkable tube, and the function of the tube may be impaired.

After the diameter is expanded, it is difficult to insert the core into the cold shrinkable tube. In the above prior art, a support is arranged between the rotating rolls in order to suppress the central portion of the rotating roll from bending when the diameter is increased. However, if there is a column between the rotating rolls, the core cannot be inserted into the cold shrink tube, and the column must be removed.

After the core is inserted into the cold shrink tube, it is difficult to pull out the rotating roll from between the cold shrink tube and the core, and the inner peripheral surface of the cold shrink tube may be damaged. When the core is inserted into the cold-shrinkable tube, the rotating roll is strongly sandwiched between the core and the self-shrinking force of the tube, and the rotating roll must be smoothly pulled out of this state. At this time, it is very important not to damage the inside of the cold-shrinkable tube in terms of electrical characteristics. In particular, if the diameter of the rotating roll is large, the contact area with the cold shrink tube becomes large, and it is extremely difficult to achieve both smooth extraction of the rotating roll and prevention of damage in the cold shrink tube.

Therefore, the present invention provides an apparatus for expanding a room-temperature shrinkable tube and a method for expanding the room-temperature shrinkable tube with good workability which can uniformly expand the diameter of the room-temperature shrinkage tube without damaging the inside thereof and reduce the burden on an operator. provide.

[0010]

SUMMARY OF THE INVENTION The present invention achieves the above object by enabling a stepwise expansion of a cold-shrinkable tube. That is, the diameter expanding apparatus of the present invention is an apparatus that expands the diameter of the tube larger than the outer diameter of the core by inserting a plurality of rods into the cold shrinkable tube and moving the rods so as to increase the interval between the rods. It is. The diameter expanding device includes a plurality of rods inserted into the cold shrink tube and a diameter expanding mechanism for moving the rods in a radial direction. The diameter expansion mechanism has a rod-shaped body gripper and a slider for moving the gripper forward and backward. The grip portion of the rod has a configuration corresponding to rods having different diameters.

The rod-shaped body, which is inserted into the cold-shrinkable tube to expand the diameter of the tube, expands against the self-shrinkage force of the tube. Metallic materials such as steel are desirable. In particular, a linear round bar having a smooth surface so as not to damage the inner peripheral surface of the cold shrink tube is preferable. Further, the rod-shaped body is preferably sufficiently longer than the cold-shrinkable tube so as to be easily held by the grip portion. On the surface of the rod,
Before insertion into the cold shrink tube, it is preferable to apply a lubricant such as grease in advance in order to reduce friction when the core is pulled out from the cold shrink tube.

It is desirable that the diameter expanding mechanism is disposed on a flat plate so that the rod-shaped body can be moved radially on the same plane. Here, in order to uniformly expand the diameter of the cold-shrinkable tube, it is desirable to expand the diameter while keeping the inner shape of the tube, that is, the cylindrical shape as much as possible. Therefore, it is suitable to arrange the diameter expanding mechanism in a circular shape in order to correspond to the cylindrical cold shrink tube. For example, it is preferable that a circular working hole is provided in the plate, and the diameter expanding mechanism is radially arranged on the circumference of the working hole centered on the axis of the working hole. In addition, it is desirable that the diameter-expanding mechanism is arranged equiangularly with respect to the axis of the working hole and so as to have the same radial distance from the axis in order to keep the cylindrical shape of the cold-shrinkable tube as much as possible. That is, it is desirable that the diameter expanding mechanism is arranged in a regular polygonal shape along the circumference of the working hole. With this arrangement, the diameter expanding device of the present invention is configured to expand the diameter of the tube by radially moving the rod-shaped body gripped by the diameter expanding mechanism in the radial direction of the working hole of the plate. It is sufficient that the working hole is sufficiently larger than the outer diameter of the cold-shrinkable tube and has such a size that the tube can be expanded so that the core can be inserted.

In the present invention, it is preferable that the diameter-enlarging mechanism is provided at two places in the rod-like body which are separated from each other in the longitudinal direction.
By gripping the rod at two places, the diameter expansion mechanism
The rod-shaped body can be securely held, and the diameter of the cold-shrinkable tube can be expanded against the self-shrinkage force of the cold-shrinkable tube. For example, a pair of plates provided with the working holes may be provided, and both plates may be arranged to face each other in the longitudinal direction of the rod-shaped body. At this time, it is desirable that at least one plate is configured to be movable so that it can be adjusted according to the length of the cold-shrinkable tube.
Here, it is preferable that the working holes provided in each plate are concentric circles so that the diameter expansion mechanism is evenly arranged and the rod-shaped body is easily moved. At this time, the diameter expansion mechanism may be arranged so as to be at the same position on both plates.

In the diameter expanding mechanism, the grip portion of the rod-shaped body has a configuration corresponding to rod-shaped bodies having different diameters. Specifically, an insertion hole that is formed in advance to fit the diameter of the rod-like body and is detachable from the slider, or a mechanism that is integrally formed with the slider and that can be opened and closed to adjust the gripping interval according to the diameter of the rod-like body May be provided. The mechanism that can be freely opened and closed is preferably configured to be capable of being tightened by a bolt or capable of continuously changing the opening and closing width by an elastic body such as a spring. In addition,
Since the cold shrink tubing before diameter expansion is relatively small,
The plurality of rods inserted into the inside of the tube are in a state in which they are close to each other and closely spaced from each other. Therefore, it is desirable that the vicinity of the distal end of the grip portion is tapered in order to prevent the rod-shaped body from being in contact with each other and becoming difficult to grip. By this shape, even if it is a small-diameter room-temperature shrinkable tube before the diameter expansion, the rod-shaped body inserted into the tube can be easily gripped. It is desirable that such a grip portion be provided near the end of the slider.

The whole of each slider is held by a slide holder and slides radially in the radial direction of the working hole of the plate. It is preferable that each slider be connected to a motor and moved by the motor because of good workability. This slider can slide against the self-shrinkage force of the cold-shrinkable tube to be expanded, that is, the rod-shaped body does not flex excessively or move away from the slider during movement (during expansion), and the slide holder has Anything that moves smoothly can be used.

It is desirable to attach a sensor to the slider so that its movement state can be confirmed. It is desirable that the sensor is configured to be able to mutually grasp the moving distance of each bar. By providing the sensor, for example, the sliders can be simultaneously moved radially by the same distance, so that the present invention enables the cold-shrinkable tube to be uniformly expanded. As such a sensor, for example, there is a configuration in which a member having a slit is fixed in parallel with a slider, and the movement of the slit is grasped by a photo sensor.

The shape of the slide holder for holding the slider is not particularly limited as long as it can fit the shape of the slider and move the slider smoothly. For example, the slider may be held in a cylindrical shape adapted to the shape of the slider, or an axial slide holder may be inserted inside the slider.

The above-described diameter increasing mechanism including the slider having the grip portion near the tip and the slide holder holding the slider is provided at a position where the grip portion projects from the inner peripheral surface of the working hole of the plate. Is preferred. With this configuration, the maximum moving distance of the rod-like body is substantially equal to the radius of the working hole, and the working hole can be effectively used.

The motors for moving the sliders may be independently driven for each slider, but it is preferable to connect a controller and drive a plurality of the motors simultaneously. Such a control device may be any as long as it can store the optimal slide movement amount in accordance with the material and diameter of the cold shrink tube and can adjust the movement amount. The diameter expanding device of the present invention is:
By moving a plurality of rods radially and equidistantly by such a control device, it is possible to uniformly expand the diameter of the cold-shrinkable tube.

The amount of movement of the slider may be set according to the following procedure. First, a rod-shaped body is appropriately inserted according to the material and diameter of the room-temperature shrinkable tube, and the moving distance in the expanded state at that time is converted into a numerical value (a physical numerical value such as a distance and the number of rotations of a motor) and provided in a control device. It is stored in a storage medium (memory). At this time, it is easy to use if it is divided into stages according to the diameter expansion amount. And according to each cold shrink tube,
By recalling these values from the memory, it is possible to always expand the tube by a certain amount.

The method for expanding the diameter of a cold-shrinkable tube according to the present invention comprises the following steps. (1) A step of inserting a plurality of rods into a cold-shrinkable tube. (2) A step of moving the rod in the radial direction to expand the cold-shrinkable tube larger than the outer diameter of the core. (3) A step of inserting the core into the expanded cold shrinkable tube.

In this method of expanding the diameter, it is appropriate to gradually increase the diameter of the rod-shaped body in order to expand the cold-shrinkable tube almost uniformly so that the expanded state is not biased. More preferably, the cold-shrinkable tube is preliminarily expanded with a small-diameter rod, and the tube is expanded with a large-diameter rod so as to be larger than the outer diameter of the core (final diameter expansion). The number of steps for changing the diameter of the rod is not particularly limited, but the number of replacements of the rod increases as the number increases, so that a diameter of about two steps is preferable. In the pre-expanding step, it is preferable that the number of rods is also increased stepwise. For example, first, three small-diameter rods are used, and the cold-shrinkable tube is expanded so that five small-diameter rods can be inserted. Then, the diameter is further increased by five small-diameter rods, and the final diameter expansion is preferably performed by using five large-diameter rods.

When the diameter is increased at once as in the invention disclosed in Japanese Patent Application Laid-Open No. 10-337778, a rod-shaped body having a tensile force capable of resisting the self-shrinkage force of the cold-shrinkable tube is required. I have to increase it to some extent. However, with such a large-diameter rod-shaped body, it is difficult to insert the core into the cold-shrinkable tube as well as to remove it after inserting the core. Therefore, first, using a small-diameter rod-shaped body, perform a pre-expansion to expand the large-diameter rod-shaped body into a size that can be inserted, and then perform a diameter expansion larger than the outer diameter of the core with a plurality of large-diameter rod-shaped bodies. It is desirable. By this diameter expanding method, it is possible to uniformly expand the diameter of the room-temperature shrinkable tube without a partial difference in expansion and contraction.

In the above, since the diameter is increased by a plurality of rods, the self-shrinkage force of the cold shrinkable tube applied per tube is smaller than that of a small number of rods, so that the rods after the diameter expansion are removed. Work is also easier.

In the present invention, it is preferable that the rods are arranged in a regular polygonal shape, and the cold shrinkable tube is expanded while maintaining the regular polygonal shape. By expanding the diameter into a regular polygonal shape, there is almost no damage due to partial expansion and contraction on the inner peripheral surface of the cold shrinkable tube, and there is little possibility that the functions of the tube are impaired.

In such an expansion of the regular polygonal shape, it is particularly preferable to expand the inside of the cold shrinkable tube larger than the outer diameter of the core while maintaining a regular pentagonal shape by using five rods. It is. With four or less, there is a difference in expansion and contraction between the part in contact with the rod-shaped body and the part not in contact with the cold-shrinkable tube, which makes it difficult to spread uniformly. If the number is six or more, the shape becomes close to the cylindrical shape, which is the inside shape of the cold shrinkable tube, and can be spread more uniformly. However, it takes time and effort to insert and remove the rod-like body inside the tube.

When the cold shrink tube is expanded using five rods, it is preferable to arrange ten expansion mechanisms on the plate so as to form a regular decagonal shape. And when changing the diameter of the rod-shaped body step by step, of the ten diameter expansion mechanisms,
By using five alternate diameter expansion mechanisms, it is not necessary to replace the rod-like body for each step, and the workability is good.

In a cold-shrinkable tube for the purpose of insulation,
If the inner peripheral surface is damaged, dielectric breakdown occurs from the damaged portion, and it is difficult to sufficiently perform the insulating function. Therefore, in order to protect the inner peripheral surface of the cold-shrinkable tube when removing the rod-shaped body, it is preferable to use the large-diameter rod-shaped body inserted into the tube at a low friction tube. Although the shape of the low friction tube is not particularly limited, it is preferable that the tube be formed into a flat band by pressing in the circumferential direction. The size of the low friction tube is desirably about the same as the diameter of the rod-shaped body in order to reduce the contact area with the inner peripheral surface of the cold shrink tube. As a material of the low friction tube, for example, a fluororesin such as polytetrafluoroethylene having a small friction coefficient and being flexible is preferable in order to facilitate an operation of removing the tube.

The low-friction tube may be inserted straight into a cold-shrinkable tube having a rod-like body inserted therein. However, in order to facilitate the removal of the low-friction tube, it may be used by breaking it into two. preferable. At this time, the low-friction tube is preferably provided with a cutout near the bent end of the tube so that a rod-shaped body can be inserted, and the rod-shaped body is desirably inserted into the notch from an opening at one end of the tube. . Then, the insertion side into which the rod is inserted and the other cavity side are overlapped, and the cavity side is preferably arranged so as to be in contact with the inner peripheral surface of the cold-shrinkable tube. At this time, the notch provided for inserting the rod-shaped body comes into contact with the outer peripheral surface of the core. While the rod is inserted through the low-friction tube, the cold-shrinkable tube is expanded to have a diameter larger than the outer diameter of the core. After the expansion, the low-friction tube is removed in the same manner as the rod. On this occasion,
It is preferable that the bent end and the two open ends of the low-friction tube which are broken into two so as to be easily removed have a length protruding from the end of the cold-shrinkable tube. That is,
The length of the folded low friction tube should be longer than the length of the cold shrink tube.

The low-friction tube may be removed by pulling out the low-friction tube on the insertion side projecting from the end of the cold-shrinkable tube from the opening side. At this time,
Since the notch provided in the low friction tube is drawn out along the outer peripheral surface of the core, the notch does not damage the inner peripheral surface of the cold-shrinkable tube. Further, since the insertion side and the cavity side of the two-folded low friction tube are in contact with each other, the surfaces on both sides rub and gradually slide as the tube is pulled out, thereby reducing friction and facilitating the removal operation.

When connecting the terminal fitting to the rubber molded product (tube), an adhesive is used to securely fix the two. The adhesive needs to be applied to the inner peripheral surface of the cold-shrinkable tube. However, when the adhesive is applied before the diameter expansion, it can be easily applied because the room-temperature shrinkable tube is stable, but peels off at the time of the diameter expansion. Further, after the diameter expansion, it is extremely difficult to apply the adhesive to the inner peripheral surface of the cold shrink tube while maintaining the expanded state. Therefore, an adhesive is applied to a necessary area on the outer peripheral surface of the core. When removing the rod-shaped body on the adhesive applied part of the core,
It is preferable to provide a protective cover so that the adhesive does not peel off due to the contact. The protective cover is capable of withstanding the compression by the self-shrinking force of the cold-shrinkable tube, and is preferably a metal tube made of stainless steel or the like, which hardly adheres to the adhesive. The inner diameter of the protective tube may be larger than the outer diameter of the portion of the core where the adhesive is applied, but if it is too large, the cold shrink tube must be expanded by that amount, so that the adhesive does not touch the adhesive. The size may be of the order of magnitude. Specifically, it may be larger than the outer diameter of the core by about 2 to 3 mm.

After mounting the core inside the cold shrink tube,
Since the protective tube must also be removed, it is preferable to apply a powder mainly composed of talc or the like to the outer peripheral surface of the protective tube so that friction at the time of removal can be reduced. For example, powder such as baby powder is preferable. Also, in order to reduce the contact area with the cold shrink tube, the outer peripheral surface of the protective tube may be provided with irregularities. For example, a groove formed in the surface of the protective tube in which a plurality of grooves along the longitudinal direction are arranged in the circumferential direction, and formed in a wave shape when viewed from the axial direction (cross-sectional direction). By providing such a groove, the lubricant applied to the surface of the rod-like body easily adheres, and it is also effective to reduce the resistance when removing the rod-like body. The end of the protective tube may be tapered to prevent it from falling off the core. Alternatively, at the time of insertion, the end of the protective tube may be pressed down by hand or the like to prevent the protective tube from falling off. With such a protective cover attached, the core is inserted into the cold-shrinkable tube expanded in diameter. The protective tube is removed by pulling it out in the same manner as the rod. Note that a putty for metal or the like may be applied as an adhesive, or a putty tape or the like may be wound.

As the room-temperature shrinkable tube to be expanded by using the expanding device or the expanding method of the present invention, a relatively soft tube made of silicon rubber or the like is optimal. On the other hand, the core to be inserted into the cold-shrinkable tube needs to be removed after the tube is placed at the cable connection portion. Therefore, the core may be divided into several parts with intermittent cuts so as to be easily removed, or in a spiral shape so that a part of the band is overlapped with a strip disclosed in Japanese Utility Model Publication No. 2-1816. It is preferable that the overlapped portion is wound and welded at intervals in the circumferential direction. Such a core is preferably formed of a resin such as polypropylene. The total length of the core is preferably longer than the cold-shrinkable tube so that the work is easy.

[0034]

Embodiments of the present invention will be described below. FIG. 1 is a top view of the diameter expanding device 1 of the present invention, and FIG.
Is a sectional view thereof, FIG. 3A is a left sectional view thereof, and FIG. 3B is a right sectional view thereof. The diameter expanding device 1 has a moving plate 3 and a fixed plate 4, and includes a moving mechanism of the moving plate 3. Each of the plates 3 and 4 includes a diameter expanding mechanism 2 for gripping and moving the rod-shaped body 2 in a radial direction, and a control device (not shown) for adjusting the movement of the diameter expanding mechanism 2. A plurality of the diameter-enlarging mechanisms 2 are radially arranged along the outer periphery of the working hole 5 around the axis of the concentric working hole 5 provided near the center of the plates 3 and 4. Both plates 3.4
, A drive shaft 6 and two driven shafts 7A and 7B are penetrated, and the moving plate 3 is moved in the axial direction by these shafts 6 and 7A and 7B. In this example, the diameter expanding device 1 is composed of an upper plate 21, a moving plate 3, a fixed plate 4, a base plate 22, and a lower plate 23 in order from the top as shown in FIG. Hereinafter, each configuration will be described.

(Plate moving mechanism) The plate moving mechanism is a mechanism that moves the moving plate 3 in the axial direction by the drive shaft 6 and the two driven shafts 7A and 7B, and adjusts the distance between the moving plate 3 and the fixed plate 4. is there. As shown in FIG. 2, the drive shaft 6 and two driven shafts 7A and 7B penetrate through the movable plate 3, the fixed plate 4, and the base plate 22, and one end of each shaft 6, 7A, 7B is an upper plate.
The other end is fixed to the lower plate 23 via a bearing 32. The base plate 22 has a motor 24 for moving the drive shaft 6.

As shown in FIG. 1, the drive shaft 6 and the driven shafts 7A and 7B are arranged on the upper plate 21 in a triangular shape having the drive shaft 6 as an apex. The upper plate 21 is a concave plate whose valley is located near the work hole 5 of the movable plate 3, and its shape makes it easy to take in and out a rod-shaped body and a core. Driven shafts 7A and 7B are fixed to both ends protruding in a concave shape, and a drive shaft 6 is arranged near the center of the valley side.

The drive shaft 6 and the driven shaft 7 are ball screws which are partially threaded as shown in FIGS. 3 (A) and 3 (B). The end of the drive shaft 6 is a bevel gear connected to a motor 24 that moves the drive shaft 6 as shown in FIG.
A bevel gear 27 that meshes with 34 and a drive pulley 28 that transmits rotational force to the driven shaft 7 are inserted. The driven pulley 29 is inserted through the end of the driven shaft 7 as shown in FIG. As shown in FIG. 2, a belt 31 is passed from the driving pulley 28 to the driven pulley 29 via a tension pulley 30, and the driven pulley 29 is interlocked with the driving pulley 28 by the belt 31. With this configuration, the bevel gear 34 is rotated by the motor 24, and the rotation of the bevel gear 34
27 rotates the drive shaft 6 in conjunction therewith. Bevel gear at the same time
The rotation of 27 is transmitted to a drive pulley 28 to rotate a belt 31, and the belt 31 rotates a driven shaft 7 via a driven pulley 29, thereby moving the movable plate 3 up and down. With this configuration, the diameter expanding device 1 of the present invention can change the width of both plates 3 and 4, so that it can correspond to the length of the cold-shrinkable tube.

As shown in FIG. 2, two drive pulleys 28 are arranged vertically in the axial direction of the drive shaft 6, and one is used for rotating the driven shaft 7A and the other is used for rotating the driven shaft 7B. In this example, the driven shaft 7A uses the upper drive pulley 28 and
The rotation of the drive shaft 6 is transmitted by a driven pulley 29 mounted on the driven shaft 7A via a tension pulley 30 fixed to 22. The driven shaft 7B uses a lower drive pulley 28, and the rotation of the drive shaft 6 is transmitted by a driven pulley 29 mounted on the driven shaft 7B via a tension pulley 30 fixed to the lower plate 23.

(Diameter Expansion Mechanism) The diameter expansion mechanism 2 is a mechanism for expanding the diameter of the room-temperature shrinkable tube by gripping the rod-shaped body and moving the rod-shaped body in the radial direction. As shown in FIG. 1, a plurality of diameter expanding mechanisms 2 are radially arranged along the outer periphery of the work hole 5 around the axis of the work hole 5 provided in both plates 3, 4. In this example, the working hole 5 is divided into ten equal parts around the axis, and ten radial expansion mechanisms 2 are arranged at equal radial distances from the axis. The arrangement position of the diameter-enlarging mechanism 2 is matched between the plates 3 and 4.

FIG. 4 is an enlarged view of the diameter expanding mechanism 2 arranged on the movable plate / fixed plate. FIG. 4A is a plan view showing a state where a cover 44 of the slide holder 43 is removed,
(B) is a plan view showing a state where the cover 44 is attached, and (C)
Is an explanatory diagram of a sensor portion. FIG. 4 (A)
As shown in FIG. 2, a gripping metal 41 that is detachable from a slider 42 that is a gripping portion of a rod-like body, a slider 42 that attaches the gripping metal 41 to an end portion and moves forward and backward in a radial direction of a working hole of both plates, and a slider 42. And a slide holder 43 to be held.

The grip metal 41 is mounted such that the portion where the rod is gripped protrudes from the end of the slider 42, and the slider 42 is placed in a state where the grip metal 41 protrudes from the end surface of the slide holder 43. It is fitted so that it becomes.

FIG. 5 is an enlarged view of the holding fittings 41A and 41B. Clamping bracket 41
A / 41B is composed of a holding portion 41a having an insertion hole 51 for inserting and gripping a rod-shaped body, and a mounting portion 41b fitted into the slider. The holding portion 41a has an insertion hole 51 at the end corresponding to the diameter of the rod. The insertion holes 51 are as shown in FIGS.
As shown in the figure, the shape is a circle corresponding to the rod. Such a gripping metal 41B is preferably attached to the diameter-enlargement mechanism 2 provided on the moving plate. FIGS. 5A and 5B show a shape in which a part of the insertion hole 51 is cut off along one side of the holding portion 41a so that the rod-shaped body can be easily fitted. The grip metal 41A is attached to the diameter-enlargement mechanism 2 provided on the fixing plate. That is, when the rod-shaped body is gripped by being inserted through these gripping fittings 41A and 41B,
The grip metal 41B is fixed to the diameter-expanding mechanism 2 in advance, and one end of the rod is inserted from the upper surface of the grip metal 41B. Then, the holding member 41 </ b> A is inserted through the other end of the rod-shaped body and mounted on the diameter-expanding mechanism 2. The corner of the holding portion 41a has a tapered shape cut off at a certain angle. With this shape,
Each of the holding portions 41a can be brought closer to each other. It is easy to grasp the rod-shaped body.

The holding portion 41a is a step protruding from the mounting portion 41b. On the other hand, a notch corresponding to the step is formed at the tip of the slider 42, and the step is fitted into the notch. It is attached by inserting. The holding brackets 41A and 41B are
b is a convex shape having a partly wide portion. The convex mounting portion 41b is fixed by being fitted to the slider 42, so that the grip metal 41 does not fall off the slider 42 during the diameter expansion. Note that the holding portion 41a has a certain thickness in the axial direction of the insertion hole 51 so as to securely hold the rod-shaped body, and is thicker than the thickness of the mounting portion 41b in the axial direction of the insertion hole 51. Therefore, the holding portion 41a and the mounting portion 41b are
There is a step in the axial direction of 51, and this step is brought into contact with the end face of the slider 42 to serve as a stopper, so that the gripping metal 41 is hard to fall off from the slider 42.

As shown in FIG. 5, each of the holding fittings 41A and 41B includes a holding portion 41a corresponding to the diameter of the room-temperature shrinkable tube, and is a member that can be detachably attached to the slider 42. In this example, as shown in FIGS. 5B and 5D, for a large-diameter rod-shaped body, the holding portion 41a is enlarged in order to increase the gripping force.

Sensor As shown in FIG. 4B, an end of the slider 42 has a sensor 4
6 is fixed. As shown in FIG.
It is a metal fitting with a short side protruding and fixed to the upper surface of the slider 42, and a long side is arranged so as to be parallel to the slider 42 without fixing the end thereof anywhere. A gap 48 is provided on the long side, and a photo sensor 47 is provided on the upper surface of the cover 44 of the slider 42. That is, the sensor
Reference numeral 46 denotes a configuration in which a gap 48 is adjusted to the photo sensor 47 before the movement of the slider 42, and the movement distance of the slider 42 is grasped by the number of rotations of the motor after the gap 48 has passed the photo sensor 47 after moving. It is. This sensor 46
Is provided in each diameter expansion mechanism 2.

Slider / Slide Holder The slider 42 is a substantially rectangular parallelepiped block, and has a groove for fitting the holding fitting 41 at one end and a motor 45 connected to the other end. The slide holder 43 has a rectangular parallelepiped groove corresponding to the slider 42,
The upper surface is covered with a cover 44. A motor 45 is connected to an end of the slider 42, and the slider 42 is moved forward and backward by the motor 45. Motor 45
Is connected to a control device (not shown), and adjusts the amount of movement of the slider 42 by the control device. Adjustment of the movement amount includes a method of manually operating the control device and a method of automatically keeping the movement amount constant. In order to automatically make the moving amount constant, first in the first diameter expanding operation, the optimum moving amount is stored in the storage medium by manual operation according to the material and diameter of each cold shrink tube. This storage is performed for each of the movement amount of the rod used for the preliminary diameter expansion and the movement amount of the rod used for the final diameter expansion. From the second time onward, the amount of movement of the slider 42 is automatically adjusted by calling this memory. With the control device, the diameter expanding device 1 can simultaneously move the plurality of sliders 42 radially, and since the moving distances are equal at the same time, the diameter is uniformly expanded without a partial difference in expansion and contraction inside the cold shrink tube. be able to.

FIG. 6 is a sectional view of the diameter-enlarging mechanism 2 disposed on the fixed plate. FIG. 6A is a view showing a state where the slider 42 is retracted, and FIG. It is a figure showing the expanded state. The slider 42 shown in FIG.
Is a state in which the end face of the protruding grip portion of the grip metal 41 attached to the end of the slider 42 is brought close to the inner periphery of the working hole 5. From this state, when the slider 42 is moved in the radial direction of the working hole 5 toward the shaft 61 of the working hole 5, the end faces of the opposite gripping metal fittings 41 are almost in contact with each other as shown in FIG. Therefore, the slider 42 is provided with the work hole 5.
The diameter expanding device 1 can expand the cold shrinkable tube having a diameter corresponding to the range of the slider 42 advance and retreat.

(Receiver / Reinforcement Plate) As shown in FIG. 2, a support 25 is provided below the working hole 5 of the fixing plate 4 on the base 22 as a stop when the rod 8 is inserted. .
The pedestal 25 connects the bolt 25a downward, and the bearing 25b
And is fixed to the lower plate 23 via. A member to which a handle 26 is attached is fitted to the bolt 25a.
By rotating the handle 26 according to the length of the cradle 25, the height of the cradle 25 is adjusted. On the other hand, as shown in FIG. 3A, in this example, a reinforcing plate 33 is arranged from the fixed plate 4 to the upper plate 21. In order to dispose the reinforcing plate 33, the upper plate 21 and the plates 3 and 4 have a polygonal shape with corners dropped.

(Rod) In this example, a round bar made of bearing steel is used. The length of the rod is appropriately changed according to the length of the cold-shrinkable tube to be expanded.
Use a tube that is long enough to be gripped with the tube.

(Core) The core is spirally wound by overlapping a part of a band formed of a resin such as polypropylene disclosed in Japanese Utility Model Publication No. 2-1816, and the overlap is circumferentially spaced. Use the one that has been opened and welded. The total length of the core is longer than that of the cold-shrinkable tube and shorter than that of the rod so as to facilitate the operation.

(Normal Shrink Tube) FIG. 8 shows an example of a normal shrink tube 81 used in the diameter expanding apparatus of the present invention. The cold-shrinkable tube 81 is an insulating tube made of silicon rubber, and has a high dielectric constant portion 82 made of ethylene propylene rubber on a part of the inner peripheral surface. Coldshrink used for expanded device in this embodiment is preferably those around diameter 38mm ² 500 mm ² before enlarged diameter for 6.6kV transmission. The rod has a diameter of 3mm to 12mm in the preliminary expansion.
About a round bar is good.
A round bar of about mm is suitable. An example of an expanded state of the cold shrinkable tube as shown in FIG. 8 is shown below. Diameter 38mm ² enlarged front thickness 3 mm L _1: diameter before Fai9.8 mm diameter after 24 mm L _2: diameter before φ11.8mm expanded after φ32mm diameter 500 mm ² diameter before thickness 3 mm L _1: diameter before φ24mm diameter after φ50mm L _2: after the enlarged diameter before φ26mm diameter φ55mm

Next, the operation procedure of the diameter expanding device of the present invention will be described. In this example, the room-temperature shrinkable tube is small in diameter (φ6m
m) with a round bar (PQRST) to make a large diameter (φ8m
m), a final expansion was performed by using a round bar (UVWXY) to increase the diameter larger than the outer diameter of the core.

In the case of cold shrinkable tube The size, material, and core size of the cold shrink tube used are shown below. Cold shrink tube Diameter before expansion φ24.1mm Thickness before expansion 3mm Tube length 270mm Tube material Silicon rubber Core Outer diameter of core φ54mm Core length 320mm

(1) The movable plate 3 shown in FIG.
Widen the interval. The height of the cradle 25 is adjusted by the handle 26. In the diameter expansion mechanism 2 of the fixed plate 4,
Five staggered sliders 42 are slid in the radial direction of the working hole 5 and extended to and near the axis 61 of the working hole 5 (see FIG. 6B). Then, a grip metal 41A (see FIGS. 5A and 5B) is fitted to the end of the slider 42 of the fixed plate 4, and a round bar P having a diameter of 6 mm is inserted into the insertion hole 51 of the grip metal 41A.
Insert

(2) Insert the cold-shrinkable tube along the round bar P. Next, the round bar Q is inserted into the room-temperature shrink tube using the round bar P as a guide. The moving metal plate 3 is fitted with the holding metal fitting 41B (see FIGS. 5C and 5D) from the ends of the round bars P and Q.
The grip metal 41B is fitted to the slider 42 of the diameter-enlargement mechanism 2 provided in the above, and the two round bars P and Q are fixed to the slider 42 of both plates 3.4. Further, the round bar R is inserted into the room-temperature shrinkable tube, and is similarly fixed to the slider 42 by the holding fittings 41A and 41B. At this time, the round bars P to R are arranged so as to form a substantially isosceles triangle.

(3) The round bars P to R are moved in the radial direction of the working hole 5 toward the inner peripheral side of the working hole 5 to expand the cold-shrinkable tube so that the round bar S can be inserted. Then, the fourth round bar S is inserted through the room-temperature shrink tube, and the round bars P to R
In the same manner as described above, the diameter is further increased by fixing to the slider 42, and a gap is provided so that the fifth round bar T can be inserted. Then, the round bar T is inserted into the cold shrink tube and fixed to the slider 42. At this time, the slider 42 is adjusted by moving the slider 42 so that the round bars PT become substantially a regular pentagon. The diameter expansion in this step may be widened so that the round bar ST can be inserted so as not to damage the inner peripheral surface of the cold shrink tube.

(4) The slider 42 is moved toward the inner peripheral side of the working hole 5 in the radial direction of the working hole 5 of both plates 3.4 to expand the diameter (preliminary diameter expansion). The diameter expansion in this process is
What is necessary is just to expand it so that the large diameter round bars U to Y used in the final diameter expansion stage can be inserted.

(5) The movement of the diameter-expanding mechanism 2 is temporarily stopped in a state where the diameter is expanded so that the round bars U to Y can be inserted. Then, in the diameter expanding mechanism 2 of the fixing plate 4, the holding metal fitting 41A
The remaining five sliders 42 with the
Slide to the vicinity (see FIG. 6 (B)). Then, the round rods U to Y having a diameter of φ8 mm are inserted into the above-mentioned cold shrinkable tube, and one end is held by the holding fitting 41A. then,
The remaining five sliders 42 of the diameter expansion mechanism 2 of the moving plate 3
Is slid to the vicinity of the shaft 61 of the working hole 5, and the holding fitting 41 </ b> B is attached to the other end of the round bars U to Y and fixed to the slider 42. At this time, 10 round rods P to Y
Is inserted. Note that a lubricant such as silicon grease is applied to the outer peripheral surfaces of the round bars U to Y.

(6) The round bars U to Y are moved toward the inner peripheral side of the working hole 5 in the radial direction to expand the diameter. At this time, the pentagon formed by the small-diameter round bars PT is positioned inside the pentagon formed by the large-diameter round bars U to Y. The diameter expansion at this time should be widened to such an extent that the round bars PT do not come into contact with the inner periphery of the cold shrink tube. Then, the round bars P to T are again moved to the vicinity of the shaft 61 of the working hole 5, and the round bars P to T are extracted from the inside of the cold shrink tube. In addition, since the round bars PT do not touch the inner peripheral surface of the cold-shrinkable tube when they are removed, they do not damage the inner peripheral surface of the tube.

(7) Adjust the moving plate 3 according to the length of the cold-shrinkable tube. At this time, the moving plate 3
It is desirable that the distance between the plate and the fixing plate 4 be substantially equal to the length of the cold-shrinkable tube. This is because the pulling force due to the movement of the slider 42 decreases as the distance from the portion of the slider 42 held by the grip metal 41 increases. That is, a tensile force acts strongly on the round bar in the vicinity of the holding portion of the holding fitting 41, but the tensile force decreases as the distance from the holding portion and toward the center of the round bar decreases. Accordingly, if the portion of the round bar gripped by the grip metal 41 is extremely far from both ends of the cold shrink tube, the round bar bends near the center of the round bar, making it difficult to uniformly expand the cold shrink tube. In addition, since the cold shrinkable tube is stretched in the axial direction with the expansion, it is preferable that the moving plate 3 is pushed down to the fixed plate 4 side so as to be slightly shorter than the length of the tube, and the tube is slightly shrunk. .

(8) The round bars U to Y are moved in the radial direction of the working hole 5 toward the inner peripheral side of the working hole 5 to expand the cold-shrinkable tube (final diameter expansion). The diameter expansion at this time is made larger than the outer diameter of the core so that the core can be inserted.

(9) The movement of the diameter expanding mechanism 2 is temporarily stopped in the state where the diameter is expanded. Then, the core is inserted into the cold shrink tube from the moving plate 3 side. After inserting the core, the slider 42 is moved toward the shaft 61 of the working hole 5 so that the core is brought into close contact with the cold-shrinkable tube in order to eliminate the gap between the cold-shrinkable tube and the core.

(10) Take out the cold shrinkable tube with the core attached from the diameter expanding device 1. At this time, only the slider 42 of the moving plate 3 is slightly moved to the outer peripheral side of the working hole 5 to widen the upper end side of the cold shrink tube. Then, since the tensile force on the lower end side is smaller than that on the upper end side, the round bars U to Y
Near the lower end of the tube is directed toward the center of the cold-shrinkable tube so that it can be easily removed. Then, the room-temperature shrinkable tube equipped with the core is slightly lifted upward from the lower ends of the round bars U to Y,
The round bars U to Y are pulled out from the holding fitting 41A. On the other hand, round bar U
The upper ends of .about.Y may be removed from the apparatus 1 together with the grip metal 41B, and then the grip metal 41A may be removed from the round bars U to Y.

(11) Remove the round bars U to Y from the cold shrink tube. One end of each of the round bars U to Y is fixed with a vice or the like to support the room-temperature shrinkable tube with the core attached thereto, and is pulled out toward the other end. As for the order in which the round bars U to Y are pulled out, it is preferable to pull out round bars that are not adjacent to each other, instead of pulling out the adjacent bars. By such a pulling method, the tensile force of the round bar with respect to the cold shrinkable tube can be maintained substantially uniformly, and the tube is less likely to be loosened and wrinkled. In this example, the diameter of the room-temperature shrinkable tube after diameter expansion is φ50 mm, and the thickness is 2.5 mm.

By the above steps, for example, a molded product 71 in which the core 73 is inserted into the cold shrink tube 72 shown in FIG. The molded product 71 obtained in the above process is used for a cable connecting portion. The method of using the molded product is to pass a molded product from the cable end, connect a cable or the like, and then arrange the molded product at the connecting portion to form a core 73
By removing After the core 73 is removed, the core 73 comes into close contact with the connection portion of the cable due to the self-shrinking force of the cold shrink tube 72.

In the case of a cold-shrinkable tube for the purpose of insulation In the case of a cold-shrinkable tube for the purpose of insulation, in order to prevent the inner peripheral surface from being damaged, a round bar used in the final diameter expansion (the above process) Then, the round bar U used from (5)
Y) is used in a state inserted in a low friction tube. In this example, a fluororesin tube 91 shown in FIG. 9 is used as the low friction tube. The fluororesin tube 91 has a cylindrical shape with a fold 96 formed in the longitudinal direction. When a force is applied in the circumferential direction, the fluororesin tube 91 is crushed into a band shape. In this example, the inner diameter of the fluororesin tube 91 was slightly larger than the diameter of the round bar 94 to be inserted. Further, the length of the fluororesin tube 91 was longer than that of the room-temperature shrinkable tube in a folded state in order to be used by being folded in two.

In the above step (5), a round bar 94 inserted into the fluororesin tube 91 is used. Here, the fluororesin tube 91 is folded in two, and a cutout 92 is provided on the insertion side A into which the round bar 94 is inserted. Notch 92 in this example
Was provided in the vicinity of the folded end 95 which was folded in half. Also,
The notch 92 was provided on a peripheral wall corresponding to a substantially semicircle of the fluororesin tube 91. Then, on the insertion side A of the bent fluororesin tube 91, a round bar 94 is inserted into the notch 92 from the opening 93. At this time, the end of the round bar 94 is protruded from the fluororesin tube 91 to such an extent that the tube can be held by the diameter-expanding mechanism, and the covering portion C of the tube 91 in the round bar 94 is provided to be longer than the room-temperature shrinkable tube. The other cavity side B is placed in a cold-shrinkable tube as it is. At this time, the notch 92 into which the round bar 94 is inserted is on the outer peripheral side of the core, that is,
The fluororesin tube 91 on the cavity side B is disposed so as to be in contact with the inner peripheral surface of the cold shrink tube. The two-folded fluororesin tube is inserted into the cold-shrinkable tube with the insides of the folded tubes in contact with each other.

In the above step (11), similarly, the round bars U to Y
, And then the fluororesin tube 91 is removed. The fluororesin tube 91 from which the round bars U to Y have been pulled out is crushed along the crease by the self-shrinking force of the cold shrink tube to form a band, and is in contact with the outer peripheral surface of the core (the inner circumferential surface of the cold shrink tube). . The removal of the fluororesin tube 91 is performed by pulling out the insertion side A (see FIG. 9) through which the round bars U to Y have been inserted among the two sides folded with pliers or the like. Accordingly, the holes provided for passing the round bars U to Y move toward the core side, so that the inner peripheral surface of the cold-shrinkable tube is not damaged. In addition, since the fluororesin tube 91 is folded in two, the inner surfaces of the folded tube 91 slide with each other to reduce friction and facilitate pulling out.

Terminal fitting and rubber mold (tube)
In the case of connecting a product In a terminal connection of a cable connecting a terminal fitting and a cable, in order to securely fix the connection portion, the connection portion is coated with an adhesive and connected. Before inserting the core in the step (9), a metal putty is applied as an adhesive to an outer peripheral surface near an end of the core (near a connection) in advance. At this time, a stainless protective tube is inserted around the outer periphery of the round bar U to Y so that the adhesive does not peel off due to friction when the bar is pulled out. In this example, the protective tube has a length corresponding to the portion on which the adhesive is applied, and its inner diameter is about 2 mm larger than the outer diameter of the core so as not to contact the applied adhesive.
The outer peripheral surface of the protective tube has a shape having a plurality of longitudinal grooves. At the end of the protective tube, a recess is provided on the inner peripheral side to make it difficult for the protective tube to fall out of the core. In this example, talc powder is applied to the outer peripheral surface of the protective cylinder in order to reduce the resistance when removing the cold shrinkable tube after mounting.

In step (9), the protective tube is inserted into the cold shrinkable tube so as not to fall off the core.

In the step (11), after the round bars U to Y are pulled out of the cold shrink tube, the protective tube is removed. The protective tube may be removed by pulling out its end with pliers or the like. At this time, the talc powder reduces friction and is easy to pull out. When the fluororesin tube is used for the purpose of insulation as described above, the protective tube is removed after removing the fluororesin tube.

[0072]

As described above, according to the diameter expanding apparatus of the present invention, an excellent effect can be obtained in that the cold shrinkable tube having the self-shrinkage property can be easily expanded and the burden on the operator can be reduced. In addition, since the diameter-expanding device of the present invention expands the cold-shrinkable tube in a regular polygonal shape, the tube can be uniformly expanded with little difference in expansion and contraction. Furthermore, since the diameter expanding device of the present invention expands the diameter of the rod by changing the diameter of the rod in a stepwise manner, an unreasonable tensile force is applied compared to the case where the room-temperature shrinkable tube is expanded at a time with a large diameter rod. It is difficult to make a difference in the expanded state. In addition, since the diameter expanding device of the present invention covers the rod-shaped body with the low friction tube, it does not damage the inner peripheral surface of the cold shrink tube. Therefore, the diameter expanding device of the present invention is less likely to impair each function of the cold shrink tube due to damage to the inner peripheral surface of the cold shrink tube.

In addition to the above, the diameter expanding device of the present invention expands the cold-shrinkable tube with a rod, so that the area in contact with the inner peripheral surface of the tube is small. It is less likely to contaminate the inside of the tube and to leave lubricant on the inner peripheral surface of the tube.

[Brief description of the drawings]

FIG. 1 is a top view of a diameter expanding device of the present invention.

FIG. 2 is a sectional view of the diameter expanding device of the present invention.

FIG. 3A is a left sectional view of the diameter expanding device of the present invention, and FIG.
Is a right sectional view thereof.

4 (A) and 4 (B) are enlarged views of a diameter expanding mechanism arranged on each plate of the diameter expanding device of the present invention, and FIG. 4 (A) is a plan view showing a state where a cover of a slide holder is removed. (B) is a plan view showing a state in which the cover is attached and a sensor is installed on the upper surface, and (C) is an explanatory view of a sensor part to be attached.

5A and 5B are enlarged views of a gripping metal attached to a diameter expanding mechanism of the diameter expanding device of the present invention, and FIGS. 5A and 5B are plan views of a gripping metal attached to a diameter expanding mechanism installed on a fixed plate; (D) is a plan view of a holding bracket to be attached to a diameter-expanding mechanism installed on a moving plate.

FIG. 6 is a sectional view of a diameter expanding mechanism provided in the apparatus of the present invention;
(A) is a diagram illustrating a state in which the slider is retracted, and (B) is a diagram illustrating a state in which the slider is extended.

FIG. 7 is a cross-sectional view of a molded product in which a cold-shrinkable tube is expanded in diameter, a core is inserted therein, and the expanded state is maintained.

FIG. 8 is a sectional view of a cold-shrinkable tube.

FIG. 9 is an explanatory view of use of a low friction tube.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Diameter expansion device 2 Diameter expansion mechanism 3 Moving plate 4
Fixing plate 5 Working hole 6 Drive shaft 7.7A, 7B Follower shaft 8 Rod 21 Upper plate 22 Base plate 23 Lower plate 24 Motor 25 Abutment 25a Bolt 25b Bearing 26 Handle 27 Bevel gear 28
Drive pulley 29 Follower pulley 30 Tension pulley 31 Belt 32 Bearing 33 Reinforcement plate 34 Bevel gear 41 ・ 41A ・ 41B Gripping bracket 41a Holder 41b Mounting part
42 Slider 43 Slide holder 44 Cover 45 Motor 46
Sensor 47 photosensor 48 rift 71 moldings 72 Coldshrink 73 core 51 insertion hole 61 axis 81 Coldshrink 82 high dielectric portion 83 the flange portion L 1 _· L ₂ the inner diameter 91 of the cold shrink tube low friction tube 92 bore 93 opening Part 94 rod
95 Folded end 96 Crease A Insertion side B Cavity side C Cover

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toru Matsumura 1-3-1 Shimaya, Konohana-ku, Osaka-shi, Osaka Sumitomo Electric Industries, Ltd. Osaka Works (72) Inventor Kiyotsu Tachikawa Shimaya, Konohana-ku, Osaka-shi, Osaka 1-3-3, Sumitomo Electric Industries, Ltd. Osaka Works (72) Inventor Hiroyuki Hidaka 3-57 Takasago, Takaishi-shi, Osaka Prefecture F-term (reference) 4F210 AA09 AA35 AA45 AG03 AG08 RA01 RC05 RG01 RG07 RG09 RG30 RG57 5G333 AA09 AA13 AB23 BA01 CB19 DA03 5G375 AA02 BA26 BB43 CA02 CB07 DB32

Claims (8)

[Claims] 1. A cold-shrinkable tube comprising a plurality of rods inserted into a cold-shrinkable tube; and a diameter-expansion mechanism for radially moving the rod-shaped body to expand the tube larger than an outer diameter of a core. The diameter expanding device includes a grip portion for holding rods having different diameters, and a slider for moving the grip portion forward and backward. 2. The room-temperature expansion device for a cold-shrink tube according to claim 1, wherein the diameter-expansion mechanism is provided at two places in the rod-shaped body separated from each other in the longitudinal direction. 3. The cold expansion tube expanding device according to claim 1, wherein the grip portion of the expanding mechanism is detachable from the slider. 4. A step of inserting a plurality of rods into the cold-shrinkable tube, a step of radially moving the rods to expand the tube larger than the outer diameter of the core, A step of inserting a core into the inside of the tube, and increasing the diameter of the rod-shaped body in a stepwise manner to expand the tube. 5. The cold-shrinkable tube according to claim 4, wherein the cold-shrinkable tube is preliminarily expanded with a small-diameter rod, and the tube is expanded with a large-diameter rod larger than the outer diameter of the core. Tube expansion method. 6. The cold-shrinkable tube according to claim 4, wherein the rod-like body inserted into the cold-shrinkable tube is arranged in a substantially regular pentagonal shape and expands its diameter while maintaining the regular pentagonal state. Diameter expansion method. 7. A notch is provided in the vicinity of a bent end of a low-friction tube that has been folded into two, and a rod is inserted into the notch through an opening at one end of the low-friction tube. 5. The method of expanding a cold-shrinkable tube according to claim 4, wherein the diameter is expanded by passing through the tube. 8. A step of inserting a core into the expanded room-temperature shrinkable tube, wherein an adhesive is applied to an outer peripheral surface of the core, and the adhesive is not peeled at a portion where the adhesive is applied. 5. The method of expanding a cold-shrinkable tube according to claim 4, wherein a protective cover is provided as described above, and a core provided with the protective cover is inserted through the inside of the tube.