JP5510039B2 - Manufacturing method of exterior material for wire harness - Google Patents

Description

  The present invention relates to a method for manufacturing a wire harness exterior material, and more particularly, to a method for manufacturing a heat-shrinkable net sheet wound around an electric wire group constituting a wire harness.

Conventionally, in order to bind and protect the wire group of the wire harness routed in the vehicle, and to prevent interference by an external interference material, the wire group is wrapped with adhesive tape, or the wire group is passed through a tube such as a corrugated tube or a round tube. .
Conventionally, a vinyl chloride tape has been widely used as an exterior material composed of these tapes and tubes, and polypropylene or the like has been used as a corrugated tube, both of which are made of resin. In addition, heat shrinkable tubes are also widely used recently.

  This type of heat-shrinkable tube is prepared by kneading the required resin material and feeding it into an extruder, extruding it as a tube, irradiating the molded tube with an electron beam, crosslinking it, and heating the tube after crosslinking It is manufactured by inflating by sending pressurized air into it, and then cooling and fixing it. (See JP 2006-104395 A)

JP 2006-104395 A

  When a conventional round tube-shaped heat shrinkable tube is inserted through the wire group constituting the wire harness and then heated at the heat shrink temperature, the tube shrinks and shrinks, and the inner wire group is closely focused. Adhere closely to the outer peripheral surface of the wire group. Therefore, it is suitably used as a sheathing material for wire harnesses at places where waterproofness is required.

However, when waterproofness is not required and the bundling function of the electric wire group is mainly required, it is not necessary to have a round tube shape. If the tube shape is used, the amount of resin increases, the weight increases, and the cost increases. In addition, the flexibility of the round tube shape is impaired, and there is a problem that it is difficult to bend and route the wire harness rapidly.
In addition, because it is a tube, it is necessary to insert the wire group into the hollow part from one end of the tube and pull it out from the other end. When the wire group is long, it is not easy to pass the wire group through the tube, and workability There is a bad problem.

If the heat-shrinkable tube is a net-like sheet having heat-shrinkability, the resin basis weight can be reduced, and as a result, weight reduction and cost reduction can be achieved. In addition, flexibility can be ensured, and if a sheet is used instead of a tube, the sheet can be wound from the side of the electric wire group, and the attachment workability to the electric wire group is improved.
However, a net sheet having heat shrinkability is not provided. Therefore, this invention makes it a subject to provide the manufacturing method which can manufacture easily the novel heat-shrink net | network sheet | seat which can be used suitably as an exterior material for wire harnesses with sufficient productivity.

In order to solve the above-mentioned problem, the present invention uses a resin as a material of a heat shrinkable tube, presses and heat-bonds the vertical line and the horizontal line at the intersection with a sizing machine, and either the vertical line or the horizontal line is used. Either or both of them form a net-like sheet fused to each other in a state where 40% to 50% of the cross-sectional area is melted and embedded in the other fiber ,
Next, the molded sheet is crosslinked or chemically crosslinked by electron beam irradiation,
Next, while heating the sheet, the both sides of the sheet in the width direction are respectively held by clamps provided in the chain of each conveyor at the upstream end of the pair of conveyors , and the conveyors are inclined in a direction away from each other toward the downstream. And moving while stretching the sheet width gradually and stretching it at the required stretch ratio in the width direction,
Next, the present invention provides a method for manufacturing an exterior material for a wire harness, which is cooled and fixed in the stretched state to form a heat-shrinkable net sheet.

As the heat shrinkage net sheet using chain-type conveyor, is inclined in the direction away toward the conveyor to the downstream, the grasped sheet stretched in the width direction, the length direction have a stretched. As a result, when the heat-shrinkable net sheet is wound around the wire harness in a squeeze shape and heated at the heat-shrink temperature, the length does not shrink, and the wire harness shrinks in the winding direction to converge the wires, and the outer peripheral surface of the wire group Can be adhered to.

The resin used as the material is at least one selected from flame retardant polyolefin, polyvinylidene fluoride, and polyvinyl chloride.
The resin is a resin that is widely used as a material for heat-shrinkable tubes, and is used as a flame retardant resin in order to provide an exterior material for a wire harness that is routed in a vehicle such as an automobile.
Furthermore, it is preferable to add a reinforcing material such as silica or carbon black to enhance the wear resistance.
Moreover, it is preferable to mix | blend polyfunctional monomers, such as triallyl cyanurate and triallyl isocyanate, as a crosslinking accelerator.

When forming a net-like sheet through resin through the die of the sizing machine, the intersection of the vertical and horizontal lines is heated and pressurized, so that the vertical and horizontal lines are in surface contact and from one side line to the other side line or in each other's opposite line Since they are fused so as to enter, the bonding force at the intersection can be increased, and even if a tensile force or a tearing force is applied, peeling at the intersection can be prevented. Therefore, even if a tensile force or a tearing force is applied to the net sheet, the connection between the vertical and horizontal lines will not be peeled off at the intersection point, no breakage will occur, the shape retention force will be strong, and the exterior material will be highly reliable. .
Thus, the vertical line and the horizontal line are overlapped up and down at the intersections without knitting, and either or both of the vertical line and the horizontal line are melted in 40% to 50% of the cross-sectional area in the counterpart fiber. In the embedded state, they are fused together and frayed at the cut end.

The step of imparting heat-shrinkability to the net-like sheet is a step similar to the conventional heat-shrinkable tube manufacturing step, which is crosslinked or chemically cross-linked by electron beam irradiation, pulling the net sheet only in the width direction while heating , are produced as a heat shrinkable net sheet is cooled fixed at the end.

The shape of each hole surrounded by the vertical and horizontal lines of the net sheet is a square, a rectangle, a rhombus, a hexagon, or a circle of a perfect circle, an ellipse, or an ellipse.
The shape of the holes is adjusted according to the required stretchability and strength.
That is, the size of the pores can be increased by roughening the net when the demand for stretchability is high, and increasing the size of the pores, and when the demand for strength and wear resistance is high, the net is fined. The holes are made smaller. The shape of the pores is a rhombus shape to make it easy to stretch, and a square or rectangle to make it difficult to stretch.
It is preferable that the stretching by the conveyor is expanded by 40% or more in the width direction so that the shrinkage rate of the net sheet is 40% or more .

Furthermore, a large-diameter line and a small-diameter line are provided as the vertical line and the horizontal line, respectively, and a plurality of the small-diameter lines are arranged while being sandwiched between the large-diameter lines, and the small-diameter line is formed in a hole surrounded by the large-diameter lines. It is good also as a structure which has arrange | positioned the net-shaped part.
Furthermore, the both ends in the length direction of the net-like exterior material are formed into a shape with cellage without providing holes, and the tape winding between the both ends in the length direction of the net-like exterior material and the wire group of the wire harness is made into an easy shape Also good.

The present invention provides a wire harness exterior material comprising a heat-shrinkable net sheet manufactured by the manufacturing method.
The heat-shrinkable net sheet of the wire harness exterior material is wrapped around the outer periphery of the wire group constituting the wire harness and then heated at the heat-shrink temperature to focus the wire group and adhere to the outer periphery of the wire group It is something to be made.

  The exterior material for a wire harness comprising the heat-shrinkable net sheet of the present invention can reduce the amount of the resin basis weight to half or less compared to a conventionally used resin sheet, and as a result, the exterior material for the wire harness can be reduced in weight. In addition, the cost can be reduced as compared with the heat shrinkable tube.

  As described above, according to the present invention, it is possible to easily manufacture a heat-shrinkable net sheet used as a wire harness exterior material. In addition, the net is firmly fixed because the net is fused so that one or both of the vertical and horizontal lines are buried in the line of the other party. Therefore, even if a tensile force or tearing force is applied to the exterior material consisting of a net sheet, the connection between the vertical and horizontal lines will not be peeled off at the intersection, and the wire harness exterior material will not cause breakage and has a strong shape retention force. Can do.

The heat-shrink net | network sheet | seat manufactured by this invention is shown, (A) is a top view before heat shrink, (B) is a top view after heat shrink. It is drawing which shows the process of armoring the said heat shrinkable net sheet | seat on a wire harness. (A) is a perspective view showing a resin wire that becomes vertical and horizontal lines of a heat-shrinkable net sheet, (B) is a perspective view showing a state in which vertical lines and horizontal lines are overlapped, and (C) is an intersection of vertical and horizontal lines. It is an enlarged view. (A) is this schematic of a net sheet manufacturing apparatus, (B) is a perspective view of the die set of a sizing machine, (C) is explanatory drawing of the process by which a net sheet is shape | molded. (A) is the schematic which shows the process of extending and fixing a net sheet, (B) is a BB arrow line view of (A).

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The embodiment is shown in FIGS.

  The exterior material for a wire harness manufactured in the first embodiment is composed of the heat-shrinkable net sheet 1 shown in FIG. When the heat shrinkable net sheet 1 shown in FIG. 1 (A) is heated above a required heat shrinkage temperature, the heat shrinkable net sheet shrinks in the width direction D at a required shrinkage rate as shown in FIG. 1 (B). It is. The shrinkage rate of the net sheet of this embodiment is 40% or more.

  As shown in FIG. 2, the heat-shrinkable net sheet 1 is stretched in the width direction D shown in FIG. 1 (A) and is wound around the outer peripheral surfaces of a number of electric wires 15 constituting the wire harness W / H. Wound, heated at the heat shrinkage temperature after winding to shrink the heat-shrinkable net sheet 1 as shown in FIG. 1 (B), and the electric wire group 15 is converged without gaps, and is closely attached to the outer peripheral surface of the converged electric wire group It is said.

  The heat-shrinkable net sheet 1 is a resin selected from flame retardant polyolefin, polyvinyl chloride, and polyvinylidene fluoride, and a reinforcing agent such as silica and carbon is blended in a required ratio. It consists of a resin composition in which a polyfunctional monomer selected from rucyanurate or triallyl isocyanate is blended in a required ratio.

  A vertical line 2 and a horizontal line 3 are formed in an elliptical cross section as shown in FIG. 3A with the flame-retardant resin wire 10 made of the resin composition, and the vertical and horizontal lines 2 and 3 are fused at an intersection point 4, It is a net shape provided with square holes 5 surrounded by vertical and horizontal lines 2 and 3.

The vertical line 2 and the horizontal line 3 are not knitted, and as shown in FIG. 3 (B), the vertical line 2 is arranged on the upper side and the horizontal line 3 is arranged on the lower side. .
At the intersection 4, as shown in FIG. 3C, the vertical line 2 and the horizontal line 3 having an elliptical cross section are in surface contact with each other, and 40 to 50% of the cross-sectional area of the lower horizontal line 3 3 m is fused in such a manner that it enters the upper vertical line 2.
Each major axis of the vertical and horizontal lines 2 and 3 is 0.35 mm to 0.5 mm, and the thickness of the heat-shrinkable net sheet 1 formed from the vertical and horizontal lines 2 and 3 is 0.4 to 0.8 mm.

A method for manufacturing the heat-shrinkable net sheet 1 having the above-described configuration will be described.
In general, first, a net-like sheet is formed using a die set of a sizing machine, and the net sheet is irradiated with an electron beam to store the shape, and then the net sheet is heated and pulled in the width direction and conveyed. And it is cooled and fixed in the pulled state.
The manufacturing process will be described in detail below.

First, a net-like sheet is formed by a sizing machine 30 shown in FIGS. 4 (A), 4 (B), and 4 (C).
The resin selected from the flame-retardant polyolefin, polyvinyl chloride, and polyvinylidene fluoride is blended with a reinforcing agent such as silica and carbon in a required ratio, and further selected from triallyl cyanurate or triallyl isocyanate. A functional monomer is blended in a required ratio and charged into the hopper 25. In this embodiment, polyvinylidene fluoride is used as a main component.

  While stirring and mixing with the hopper 25, the mixture thus stirred and mixed is conveyed to the die set 27 shown in FIGS. 4B and 4C while kneading with the screw conveyor 26, and the kneaded product is flame-retardant resin wire with the die set 27. 10 is formed as a net-like sheet.

  The die set 27 includes an out die 27a and an in die 27b. The out die 27a and the in die 27b are rotated in the opposite directions by the motor 29. As shown in FIG. 4C, the vertical line 2 and the horizontal line 3 at the portion 27c where the hole 27ah of the out die 27a and the hole 27bh of the indie 27b are overlapped. Is formed, and the holes of the out die 27a and the holes of the in die 27b are separated from each other, thereby forming a lattice shape (in this embodiment, a rhombus).

When extrusion from the die set 27 is performed, the vertical lines 2 and the horizontal lines 3 are heated and pressurized, and the vertical and horizontal lines 2 and 3 are welded. And, at the intersection 4 of the vertical and horizontal lines 2 and 3, since it is heated under pressure, at the intersection 4, the vertical and horizontal lines 2 and 3 are heat-sealed in a state of entering into the opposite fiber as shown in FIG. .
Next, the net-like sheet 40 is conveyed to the cooling tank 31, is thermally stretched by the stretching roller 32, is stretched, and is transported to the stretching tank 33, and then the sheet 40 is wound around the coil 41.

  After forming the net-like sheet 40 as described above, it is cross-linked by irradiating with an electron beam to memorize the original shape. The irradiation amount and irradiation time of the electron beam are adjusted according to the resin composition.

Next, as shown in FIG. 5, the sheet 40 is continuously carried into a heating furnace 51 provided with a heater 50 and heated.
The heated sheet 40 is continuously inserted into the stretching machine 45. In the stretching machine 45, both ends in the width direction of the net-like sheet 40 drawn from the coil 41 are gripped by clamps 47A and 47B provided in each chain at the upstream ends of the pair of conveyors 46A and 46B, and the conveyors 46A and 46B. The sheet 40 is moved while being inclined slightly upward in a direction away from each other toward the downstream side, whereby the sheet 40 is stretched by being gradually widened. The clamps 47A and 47B are removed from the downstream end, and the conveyors 46A and 46B are circulated upstream.

  After the sheet 40 is expanded by 40% or more in the width direction at the downstream end of the conveyors 46A and 46B, the sheet 40 released from the clamps 47A and 47B is passed through a cooling furnace 48 (or a cooling tank), and the sheet 40 is moved in the width direction. The sheet is cooled and fixed in the form shown in FIG.

The heat-shrinkable net sheet 1 can be manufactured relatively easily by the above process.
Since the manufactured heat-shrinkable net sheet 1 is made of a flame-retardant resin, it can also be used as an exterior material for a wire harness routed in an engine room of an automobile.
And, at the intersection 4 of the vertical and horizontal lines 2 and 3, the heat-shrinkable net sheet 1 is deformed into an elliptical cross section as shown in FIG. Since it is heat-sealed in a state, it is less likely to peel compared to the case where only the outer peripheral surfaces of the vertical and horizontal lines are welded, and it has tensile strength and tear strength. It will be expensive. Further, since the vertical and horizontal lines 2 and 3 are firmly fixed to each other, fraying does not occur at the cut ends of the vertical and horizontal lines 2 and 3.

Moreover, since the conventional heat shrinkable tube has a tube shape, it is necessary to pass the electric wire through the tube and the workability is bad. However, since it is in the form of a sheet, it is only necessary to wrap around the outer periphery of the electric wire group. Easy to package. Furthermore, the sheet used in the past had to be wound around the wire harness and then taped and fixed. However, because it is a heat-shrinkable net sheet, the net sheet is tightly fixed to the wire harness simply by heating at the required temperature. Can do.
Moreover, since it is net-shaped, the basis weight of the resin can be reduced, and the weight can be reduced by more than half compared to a round tube or a sheet that is not net-shaped. In particular, when it is used as an exterior material for a large number of wire harnesses routed in an automobile, it can contribute to reducing the weight of the automobile and improve fuel efficiency. In addition, due to the reduction in the resin weight per unit area, the manufacturing cost can be reduced as compared with a heat shrinkable tube made of a round tube.
Furthermore, since it is a net sheet, it is more flexible than a sheet that is not a net, and can follow even when the wire harness is bent at a steep angle.

1 Heat Shrink Net Sheet 2 Vertical Line 3 Horizontal Line 4 Intersection 5 Hole

Claims (4)

Using the resin used as the material of the heat shrinkable tube, the vertical line and the horizontal line are pressurized and heat-sealed at the intersection with a sizing machine, and either one or both of the vertical line and the horizontal line is 40% of the cross-sectional area. Forming net-like sheets that are fused to each other in a state in which ~ 50% is melted and embedded in the other fiber ,
Next, the molded sheet is crosslinked or chemically crosslinked by electron beam irradiation,
Next, while heating the sheet, the both sides of the sheet in the width direction are respectively held by clamps provided in the chain of each conveyor at the upstream end of the pair of conveyors , and the conveyors are inclined in a direction away from each other toward the downstream. And moving while stretching the sheet width gradually and stretching it at the required stretch ratio in the width direction,
Next, a method for producing an exterior material for a wire harness, wherein the heat shrinkable net sheet is formed by cooling and fixing in the stretched state after cooling. The resin as the material is selected from polyolefin, polyvinylidene fluoride, and polyvinyl chloride , and is expanded by 40% or more in the width direction by stretching by the conveyor, and the shrinkage ratio of the net sheet is 40% or more. The manufacturing method of the exterior material for wire harnesses as described in any one of.   The exterior material for wire harnesses which consists of a heat contraction net sheet manufactured with the manufacturing method of Claim 1 or Claim 2.   The wire harness according to claim 3, wherein the wire harness is wound around the outer periphery of the wire group constituting the wire harness and then heated at a heat shrink temperature to focus the wire group and to adhere to the outer periphery of the wire group. Exterior material.

Images