JP4349945B2 - Heat shrink tube, insulation bolt and insulation joint structure - Google Patents

Description

  The present invention relates to a heat-shrinkable tube made of a heat-shrinkable resin, an insulating bolt whose bolt body is covered with an insulating layer made of resin, and an insulating joint structure that connects a pair of conductive pipes in an insulated state.

The conventional insulated joint structure that connects conductive pipes such as gas pipes in an insulated state is that bolts and nuts are used with both flanges of a pair of conductive pipes interposed with insulating spacers as insulating members between each other. Further, a resin insulating washer is sandwiched between the seat surface of the bolt and the tightening surface of the flange and between the seat surface of the nut and the tightening surface of the flange. For example, see Patent Documents 1 and 2.)
Further, in such an insulating joint structure, in order to maintain the insulation state between the bolt body and the bolt hole of the flange, it is necessary to cover the outer surface of the bolt body with, for example, a resin insulating layer. Is formed as a cylindrical insulating bush made of resin, for example, or as a coating layer coated directly on the bolt body.

Further, in order to easily and inexpensively form an insulating layer for insulating the bolt body, it has been studied to form the insulating layer by thermally shrinking a heat shrinkable tube on the bolt body.
Conventional heat-shrinkable tubes are obtained by molding a heat-shrinkable resin such as fluororesin, silicone resin, ethylene / propylene resin, polyethylene resin, vinyl chloride resin into a relatively thin cylindrical shape.

Japanese Utility Model Publication No. 61-55578 JP-A-6-101789

  In the insulation joint structure, when the insulating layer covering the bolt body is formed by heat shrinking a conventional heat shrinkable tube, the insulation layer formed by the heat shrinkable tube is placed in the bolt hole of the flange when tightening the bolt. There is a case where the insulating state cannot be secured due to rubbing and damage.

In addition, if the thickness of the heat shrinkable tube is increased in order to prevent damage to the insulating layer formed by the heat shrinkable tube, the heat shrinkability of the heat shrinkable tube is deteriorated and the adhesion to the bolt body is reduced. Thus, there is a problem in that defective production or the like occurs, or the heating time for shrinking the heat-shrinkable tube becomes long and productivity is lowered.
Furthermore, if the thickness of the insulating layer covering the bolt body increases, the diameter of the bolt hole of the flange into which the bolt is inserted needs to be made larger than the standard one specified for the bolt size. There is.

  In addition, in order to prevent breakage due to rubbing with the bolt holes, insulation is made with fiber reinforced plastic (hereinafter referred to as FRP) in which reinforcing fibers such as inorganic fibers, organic fibers, and polycrystalline fibers are dispersed in a resin. It is conceivable to form a layer. However, a heat shrinkable tube made of FRP in which reinforcing fibers are dispersed in a resin deteriorates in heat shrinkability due to the presence of the reinforcing fibers. Even if the insulating layer covering the bolt body is made of FRP, when the bolt is inserted into the bolt hole and rotated, the inner wall of the bolt hole may be rubbed and damaged by the insulating layer.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an insulating joint structure with an insulating layer made of FRP that sufficiently secures a scratch strength against rubbing against a bolt hole on a bolt body. An insulating bolt is realized, and further, an insulating tube that can be easily applied to the bolt body as an insulating layer of the insulating bolt is realized.

  In order to achieve the above object, an insulating tube according to the present invention is a heat-shrinkable tube made of a heat-shrinkable resin, and its characteristic configuration is that a reinforcing fiber oriented in the cylinder axis direction is composited. is there.

  In the present application, to orient the FRP reinforcing fibers in the cylinder axis direction means that most of the reinforcing fibers are aligned in the cylinder axis direction. For example, the reinforcing fibers are oriented in the cylinder axis direction. It can be confirmed by observing whether the arrangement of the reinforcing fibers is biased in the cylinder axis direction or the circumferential direction. For example, the tensile strength in the cylinder axis direction of the FRP is greater than the tensile strength in the circumferential direction. It can also be confirmed by measuring whether it is too large.

According to the characteristic configuration of the heat-shrinkable tube, when the insulating tube is made of FRP and the reinforcing fiber dispersed in the FRP is oriented in the cylinder axis direction, The reinforcing fibers oriented in the axial direction come close to each other well, and deterioration of heat shrinkability is suppressed.
Therefore, when constructing a heat shrinkable tube on a work part such as a bolt body part, it improves the adhesion to the work part due to good heat shrinkability, and further reduces the heating time for shrinking the heat shrinkable tube. Productivity can be improved by shortening.

In order to achieve the above object, an insulating bolt according to the present invention is an insulating bolt in which a bolt body is covered with an insulating layer made of resin, and a composite of reinforcing fibers oriented in the cylinder axis direction on the insulating layer. Kashitea is, the insulating layer is a heat-shrinkable tube of reinforcing fibers are oriented in the cylinder axis direction are conjugated to a point Ru der those formed by heat shrinkage.

According to the characteristic configuration of the insulating bolt, the insulating layer applied to the bolt body is made of FRP, and the reinforcing fibers dispersed in the FRP are oriented in the cylindrical axis direction, thereby being oriented in the cylindrical axis direction. The reinforcing fiber can improve the scratching strength assuming friction in the circumferential direction, and even if the insulating layer is rubbed in the circumferential direction by the inner wall of the bolt hole when the insulating bolt is inserted into the bolt hole and rotated, the insulating layer Breakage can be prevented.
Further, since the reinforcing fibers of the FPR forming the insulating layer are mainly oriented in the cylinder axis direction, most of the reinforcing fibers contribute to the improvement of the scratch strength assuming the rubbing in the circumferential direction. The amount of reinforcing fibers necessary to ensure the scratch strength can be reduced as much as possible, and as a result, the thickness of the insulating layer can be made as thin as possible.

Further , according to the characteristic configuration of the insulating bolt, the heat shrinkable tube in which the insulating layer in which the reinforcing fibers oriented in the cylinder axis direction are combined is combined with the above-described reinforcing fiber in the cylinder axis directions is combined. It can be formed easily and inexpensively by heat shrinking.

The insulated joint structure according to the present invention for achieving the above object is an insulated joint structure for connecting a pair of conductive pipes in an insulated state, and the characteristic configuration is that both flanges of the pair of conductive pipes are In a state where an insulating member is interposed between them, the bolt is tightened by the insulating bolt according to claim 2 ,
Insulating washers are sandwiched between the respective bearing surfaces of the bolts and nuts and the fastening surfaces of the flanges.

  According to the characteristic configuration of the above-described insulating joint structure, both flanges of the conductive pipe are tightened using the insulating bolt that can satisfactorily prevent the insulation layer from being damaged by the inner wall of the bolt hole. A pair of conductive pipes can be connected.

  Embodiments of the present invention will be described with reference to the drawings.

  The insulating joint structure shown in FIG. 1 has both flanges F and insulating bolts 1 and nuts in a state where a non-conductive insulating packing (insulating member) 5 is interposed between both flanges F of a pair of conductive pipes P. 2, a pair of conductive pipes P are connected in an insulated state by sandwiching a non-conductive insulating washer 10 between the seating surface 1 a of the insulating bolt 1 and the fastening surface Fa of the flange F. To do.

In order to prevent the insulating washer 10 from being damaged by the seating surfaces 1a and 2a of the insulating bolt 1 or the nut 2 that are rotated when tightening and the insulating state cannot be secured, the insulating washer 10 and the seating surface 1a of the insulating bolt 1 are prevented. Between the two, a metal flat washer 3 is provided.
Further, a metal flat washer 3 and a spring washer 4 for preventing loosening are also provided between the nut 2 and the seat surface 2a.

  Further, in order to keep the insulation bolt 1 insulated from the bolt hole BH formed in the flange F, an insulation layer made of non-conductive resin is provided on the bolt body 1b so as to cover the body. 20 is given.

The insulating layer 20 applied to the insulating bolt 1 is composed of a composite of reinforcing fibers 21 oriented in the cylinder axis direction, and the reinforcing fibers 21 have a scratch strength assuming that the insulating layer 20 is rubbed in the circumferential direction. Has been improved.
That is, when the insulating bolt 1 is inserted into the bolt hole BH and rotated, even if the insulating layer 20 is rubbed in the circumferential direction by the inner wall of the bolt hole BH, the insulating layer 20 is damaged by the reinforcing fibers oriented in the cylinder axis direction. Is well prevented, and the insulation state between the insulation bolt 1 and the bolt hole BH can be ensured.

  Further, since the thickness of the insulating layer 20 is formed relatively thin since damage is prevented well as described above, the diameter of the bolt hole BH corresponds to the bolt size of the insulating bolt 1. It is assumed that the standard is specified.

  Further, as shown in FIG. 2, the insulating layer 20 of the insulating bolt 1 is formed by inserting the bolt body 1b into a heat shrinkable tube 30 in which reinforcing fibers 31 oriented in the cylinder axis direction are combined, The shrinkable tube 30 is formed by heating and shrinking with a heater.

  This heat-shrinkable tube 30 creates a tubular body of tubular reinforcing fibers 31 by spreading a fiber bundle sliver whose fiber arrangement is arranged in the longitudinal direction by cursing or the like, and creates a tubular body of the reinforcing fibers 31. It is manufactured by molding into a predetermined cylindrical shape while impregnating a heat-shrinkable resin as a matrix into the shape.

  Moreover, this heat contraction tube 30 is utilized for the use which ensures the insulation state of an electric wire and other members other than the use which ensures the insulation state of the volt | bolt trunk | drum 1b of the insulation bolt 1 demonstrated so far, for example. It doesn't matter.

  Further, as shown in FIG. 3, the heat-shrinkable tube 30 and the insulating layer 20 are a resin that forms a matrix in a state in which a plurality of filaments 41 formed by twisting reinforcing fibers in a filament form are arranged in parallel to the cylinder axis direction. The structure may be dispersed.

Schematic configuration diagram of insulated joint structure The figure explaining the formation state of the insulating layer by a heat contraction tube The figure which shows another embodiment of an insulating layer and a heat contraction tube

Explanation of symbols

1: Bolt 1b: Bolt body 2: Nut 5: Insulating packing (insulating member)
10: Insulating washer 20: Insulating layer 21, 31: Reinforcing fiber 30: Heat-shrinkable tube 41: Threaded body (reinforced fiber)
P: Conductive piping F: Flange BH: Bolt hole

Claims (3)

A heat shrinkable tube made of heat shrinkable resin,
A heat shrinkable tube in which reinforcing fibers oriented in the cylinder axis direction are combined. The bolt body is an insulating bolt covered with an insulating layer made of resin,
Wherein the insulating layer, Ri Thea complexed reinforcing fibers are oriented in the cylinder axis direction,
An insulating bolt in which the insulating layer is formed by heat-shrinking a heat-shrinkable tube in which reinforcing fibers oriented in the cylinder axis direction are combined . An insulating joint structure for connecting a pair of conductive pipes in an insulated state,
The both flanges of the pair of conductive pipes are tightened by the insulating bolts according to claim 2, with an insulating member interposed therebetween.
An insulating joint structure in which an insulating washer is sandwiched between a seating surface of each of the bolt and nut and a fastening surface of the flange.

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