JP2008296664A - Method of manufacturing of duct for automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing of a lightweight duct for an automobile, hardly causing breakage when manufacturing by increasing stiffness without increasing the mass per unit area and thickness of a porous body and capable of controlling ventilation volume. <P>SOLUTION: The porous body 31 overlaps with one side of a synthetic resin sheet 21 having a plurality of through-holes 22, heated, and directed toward a recessed die 57 while directing the synthetic resin sheet 21 toward a projecting die 59, and the synthetic resin sheet 21 and porous body 31 are pressed by the recessed die 57 and projecting die 59 to thereby form duct half bodies having a recessed cross section. After that, the side portions of the duct half bodies are joined together to thereby form the duct for the automobile. The synthetic resin sheet 21 has lower melting point than that of the porous body 31, and the heating temperature of the synthetic resin sheet 21 and porous body 31 is set higher than the melting point of the synthetic resin sheet 21 and lower than the melting point of the porous body 31. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an automobile duct.

  Conventionally, the following is known as a manufacturing method of an automobile duct used as an intake duct for an engine, an air duct for an air conditioner, or the like. For example, a non-woven fabric containing a thermoplastic binder is heated and pressed to form a half body with a substantially concave cross section, and the halves are joined to each other at the side to produce a duct for automobiles, or a film on one side of the non-woven fabric Is formed into a half body having a substantially concave cross section with a heating press or the like, and then the half bodies are joined to each other at the side so that the plastic film is on the outside. Alternatively, there is a method of manufacturing a duct for automobiles by a blow molding method that is frequently used as a method of molding a plastic hollow cylindrical body.

  However, the manufacturing method of the automobile duct for heating and pressing the nonwoven fabric containing the thermoplastic binder is heated until the nonwoven fabric is softened and shaped by pressing. Therefore, if the nonwoven fabric has a small basis weight, the rigidity is insufficient. Sometimes broken at corners. In order to prevent the nonwoven fabric from being broken during pressing, increasing the basis weight of the nonwoven fabric increases the time required for heating and pressing, increases the molding time, increases the weight of the duct for automobiles, and increases the product cost. Or the sound absorption performance of the automobile duct is lowered due to a decrease in air permeability.

  On the other hand, the manufacturing method of an automobile duct in which a film is laminated on one side of a nonwoven fabric and heated and pressed has a problem that the product cost increases due to the lamination of the plastic film, and the air-absorbing property is almost lost, so that the sound absorbing performance is lowered.

  Moreover, the manufacturing method of the duct for motor vehicles by a blow molding method has the problem that sound absorption property and heat insulation property are low, since the duct is made of hard plastic having no air permeability.

JP-A-11-343938 JP 2002-302858 A JP-A-9-264487 JP 63-53029 A

  The present invention has been made in view of the above points, and in a method for manufacturing a duct for an automobile using a porous body such as a nonwoven fabric or a synthetic resin foam, the duct without increasing the basis weight or thickness of the porous body. An object of the present invention is to provide a duct for automobiles that can increase the rigidity of the sheet to prevent tearing during production, is lightweight, and can control the air flow rate.

  The invention of claim 1 integrates and shapes by heating a synthetic resin sheet having a large number of through-holes and a porous body, and pressing the synthetic resin sheet and the porous body in a concave shape and a convex shape. Then, a duct half body having a substantially concave cross section is formed, and the duct halves are joined to each other at a side portion so that the concave surfaces are on the inner side, thereby producing a duct for an automobile.

  Invention of Claim 2 makes the said synthetic resin sheet a thing whose melting | fusing point is lower than the said porous body in Claim 1, and mounts the said synthetic resin sheet on the said porous body, performs the said heating, The heating temperature of the synthetic resin sheet and the porous body is higher than the melting point of the synthetic resin sheet and lower than the melting point of the porous body.

  The invention of claim 3 is the invention according to claim 1 or 2, wherein, in the pressing, the synthetic resin sheet is disposed toward the convex mold and the porous body is disposed toward the concave mold. The inner surface side of the duct is formed with the synthetic resin sheet, while the outer surface side of the duct is formed with the porous body.

  The invention of claim 4 is any one of claims 1 to 3, wherein the porous body is pressed against the skeleton portion and compressed in the skeleton portion other than the through hole in the synthetic resin sheet by the press. On the other hand, in the through-hole portion, the porous body is inserted into the through-hole, and the compression degree is made lower or uncompressed than the porous body portion pressed against the skeleton portion to increase the thickness. It is characterized by that.

  According to the first aspect of the present invention, the synthetic resin sheet having a large number of through-holes and the porous body are heated, and the synthetic resin sheet and the porous body are stacked and pressed in a concave shape and a convex shape, thereby integrating and shaping. In order to form duct halves having a substantially concave cross section and to join the duct halves at the sides with the concave surfaces on the inside to form a tube, the synthetic resin sheet and the porous body are integrated and applied by pressing. When forming, since the rigidity is increased by the presence of the synthetic resin sheet compared to the case of only the porous body, the thickness of the porous body is increased, or when the nonwoven fabric is used as the porous body, the weight of the nonwoven fabric is increased. Even if the amount is not increased excessively, it can be prevented from being broken at the corners and the like, and the automobile duct can be made of good quality and light weight. Furthermore, according to the invention of claim 1, since the synthetic resin sheet has a large number of through holes in the manufactured automobile duct, air permeability is ensured through the porous body at the through hole portion of the synthetic resin sheet. And the sound absorption can be improved by the air permeability. In addition, the air permeability of the automobile duct can be controlled by the size and number of the through holes.

  According to the invention of claim 2, the synthetic resin sheet has a lower melting point than the porous body, the synthetic resin sheet is placed on the porous body and heated, and the synthetic resin sheet and the porous body are heated. Since the temperature is equal to or higher than the melting point of the synthetic resin sheet and lower than the melting point of the porous body, it is possible to prevent the porous body from being melted and deformed. A decrease can be prevented. Furthermore, since the synthetic resin sheet having a temperature higher than the melting point by heating is placed on the porous body having a temperature lower than the melting point by heating, the synthetic resin sheet is placed below the synthetic resin sheet. Therefore, the synthetic resin sheet can be prevented from being deformed by its own weight, and the synthetic resin sheet and the porous body can be correctly disposed between the concave mold 57 and the convex mold 59.

  According to the invention of claim 3, during the pressing, the synthetic resin sheet is arranged toward the convex mold and the porous body is arranged toward the concave mold, and the press is used to form the duct inner surface side with the synthetic resin sheet. Since the outer surface side of the duct is formed of the material, the manufactured automobile duct has the porous body exposed in the duct only at the through hole portion of the synthetic resin sheet, and the air passes through the duct. In this case, it is possible to suppress an increase in air passage resistance due to contact with the irregularities on the surface of the porous body, and to improve the flow of air in the duct.

  According to the invention of claim 4, by pressing, the porous body is pressed against the skeleton portion and compressed in the skeleton portion other than the through-hole in the synthetic resin sheet, while the porous body is compressed into the through-hole in the through-hole portion. Because the degree of compression is lower than the part of the porous body that is inserted and pressed into the skeleton part, or the thickness is increased as non-compressed, the manufactured automobile duct has the sound in the duct at the position of the through hole. Thus, leakage through the porous body to the outside can be suppressed, and sound absorption can be enhanced. In addition, since the porous body has entered the through hole at the position of the through hole of the synthetic resin sheet, the integrity of the porous body and the synthetic resin sheet can be increased, and the rigidity of the tube wall of the automobile duct can be increased. Can be high.

  Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 is a perspective view showing an automobile duct according to an embodiment manufactured by the manufacturing method of the present invention, FIG. 2 is a perspective view showing a part of the automobile duct of FIG. 1, and FIG. 3 is a cross-sectional view, FIG. 4 is a perspective view of a synthetic resin sheet and a porous body, FIG. 5 is a schematic view of a manufacturing apparatus, FIG. 6 is a cross-sectional view showing the time of pressing, and FIG. FIG.

  The automobile duct 10 shown in FIG. 1 to FIG. 3 is manufactured by the manufacturing method of the present invention, and the half parts 11 having substantially concave cross-sections face each other with the concave surface 11a on the inner side, and the side flange part. 12, and the inside of the tubular body is an air flow passage 17 (shown in FIG. 3). The flange 12 is joined by fusion or the like. The automobile duct 10 has an appropriate cross-sectional shape and bent shape depending on the automobile to which the automobile duct 10 is mounted.

  The half body 11 is formed of a laminated body 41 in which a porous body 31 is laminated and integrated on one surface of a synthetic resin sheet 21 having a large number of through holes 22. FIG. 4 shows a synthetic resin sheet 21 having the numerous through holes 22. The synthetic resin sheet 21 having a large number of through holes 22 is a synthetic resin sheet in which a large number of through holes 22 are formed at predetermined intervals, and is also referred to as a synthetic resin net (or net). The synthetic resin sheet 21 and the porous body 31 are integrated and shaped by being heated and pressed.

  The through hole 22 may be formed at the time of manufacturing the synthetic resin sheet, or may be formed by punching or the like after manufacturing the synthetic resin sheet. The shape, size, and number of the through-holes 22 are appropriately determined. As an example, a case where the through-holes 22 are formed of a square having a side of about 3 to 10 mm and the center interval between the through-holes is about 5 to 10 mm is given.

  The thickness of the synthetic resin sheet 21 is determined in consideration of moldability when the half body 11 is molded, rigidity in the automobile duct 10, and the like. As an example, the thickness is about 1 to 4 mm.

  The synthetic resin sheet 21 is made of a thermoplastic synthetic resin such as polyethylene or polypropylene, and preferably has a melting point lower than that of the porous body 31. If the melting point of the synthetic resin sheet 21 is lower than the melting point of the porous body 31, when the half body 11 is molded by heating and pressing, the heating temperature is equal to or higher than the melting point of the synthetic resin sheet 21. If the temperature is lower than the melting point of the material 31, the porous material 31 is melted and deformed at the time of pressing to impair the porous property, whereby the air permeability and sound absorbing property of the porous material, that is, the air permeability and sound absorbing property of the duct. It is possible to prevent the performance from deteriorating. Further, the synthetic resin of the synthetic resin sheet 21 enters the porous body 31 and becomes entangled with the skeleton and fibers of the porous body 31, whereby the synthetic integration of the synthetic resin sheet 21 and the porous body 31 is strong. It has become.

  The porous body 31 is made of a non-woven fabric or a synthetic resin foam having an open cell structure. An example of the synthetic resin foam having the open cell structure is a polyurethane foam. Although the thickness of the porous body 31 varies depending on the material, about 1 to 5 mm is given as an example. Further, as shown in FIG. 3, the porous body 31 enters the through hole 22 at the position of the through hole 22 of the synthetic resin sheet 21 and is thicker than other positions. With this configuration, the sound in the duct can be prevented from leaking to the outside through the porous body 31 at the position of the through hole 22, and the sound absorption can be enhanced. Further, since the porous body 31 enters the through hole 22 at the position of the through hole 22 of the synthetic resin sheet 21, the integrity of the porous body 31 and the synthetic resin sheet 21 is high, and the duct for automobiles. The rigidity of the ten tube walls can be increased.

  Furthermore, the porous body 31 is uncompressed at the position of the through hole 22 of the synthetic resin sheet 21 or is compressed to a lower degree than the other positions, whereby the position of the through hole 22 of the synthetic resin sheet 21 is reduced. The density of the porous body 31 is coarser than the other positions (in the case of a nonwoven fabric, the spacing between fibers is coarse, whereas in the case of a foam, the density is low). Therefore, even if the thickness of the porous body 31 is large at the position of the through hole 22 of the synthetic resin sheet 21, it is possible to prevent a shortage of air permeability necessary to improve sound absorption. it can.

  In the automobile duct 10, it is preferable that the synthetic resin sheet 21 is inside the duct and the porous body 31 is outside the duct. With this configuration, the porous body 31 is exposed in the duct only at the through-hole 22 portion of the synthetic resin sheet 21, and contact with the irregularities on the surface of the porous body 31 when air passes through the duct. It is possible to suppress an increase in the air passage resistance due to this, and to improve the flow of air in the duct.

  A method for manufacturing the automobile duct 10 will be described. The manufacturing method of the automobile duct 10 includes a heating process, a pressing process, and a half body bonding process.

  An example of a manufacturing apparatus used for manufacturing the automobile duct 10 is shown in FIG. A manufacturing apparatus 51 shown in FIG. 5 is for continuously manufacturing the half body 11 and supplies the synthetic resin sheet 21 having the numerous through holes 22 and the porous body 31 in one direction. A supply unit 53; a heating unit 55 provided in the middle of supplying the synthetic resin sheet 21 and the porous body 31; and a forward direction of the synthetic resin sheet 21 and the porous body 31 with respect to the heating unit 55. It consists of a concave mold 57 and a convex mold 59. In the illustrated example, the supply means 53 is configured by a drive roller that is rotated in one direction by a drive motor (not shown), and the synthetic resin sheet 21 placed on the drive roller. The porous body 31 is supplied in the rotation direction of the drive roller.

  The synthetic resin sheet 21 having the numerous through-holes 22 and the porous body 31 are such that the synthetic resin sheet 21 has a lower melting point than the porous body 31, and is on the porous body 31 having a higher melting point. The synthetic resin sheet 21 having a high melting point is placed and supplied in one direction.

A heating step is performed at the position of the heating means 55. In the heating step, at least the synthetic resin sheet 21 is heated. The heating means 55 is composed of an appropriate heating device such as an electric heater, and is arranged vertically so as to sandwich the synthetic resin sheet 21 and the porous body 31 as shown in the figure, and the synthetic resin sheet 21 and the In addition to heating both of the porous bodies 31, they may be arranged only on one side (upper side) so as to heat only the synthetic resin sheet 21 side. The heating temperature by the heating means 55 is set to be higher than the melting point of the synthetic resin sheet 21 and lower than the melting point of the porous body 31 so that the porous body 31 is not melted and deformed. The heated synthetic resin sheet 21 and the porous body 31 are supplied to the positions of the concave mold 57 and the convex mold 59.
At the time of supply, the synthetic resin sheet 21 having a temperature higher than the melting point due to the heating is placed on the porous body 31 having a temperature lower than the melting point due to the heating. The synthetic resin sheet 21 can be supported by the porous body 31 from below and the synthetic resin sheet 21 can be prevented from being deformed by its own weight, and the synthetic resin sheet 21 and the porous sheet are interposed between the concave mold 57 and the convex mold 59. The body 31 can be arranged correctly.

  In the pressing step, cold pressing is performed. That is, as shown in FIG. 6, the synthetic resin sheet 21 heated in the heating step and the porous body 31 are stacked and pressed with the concave mold 57 and the convex mold 59 to perform integration and shaping. The concave mold 57 is positioned below the synthetic resin sheet 21 and the porous body 31, while the convex mold 59 is positioned above, and the synthetic resin sheet 21 is arranged toward the convex mold 59. At the same time, the porous body 31 is arranged toward the concave mold 57 side, and the concave mold 57 and the convex mold 59 are brought close to each other, whereby the synthetic resin sheet 21 and the porous body 31 are pressed. The concave mold 57 forms the outer surface side of the automobile duct 10, and the convex mold 59 forms the inner surface side of the automobile duct 10.

  In the skeleton portion 24 (shown in FIG. 4 and the like) other than the through hole 22 in the synthetic resin sheet 21 by the pressing, the porous body 31 is pressed against the skeleton portion 24 and compressed, while the through hole 22 is compressed. In this part, the degree of compression is made lower or uncompressed than the part of the porous body 31 in which the porous body 31 enters the through-hole 22 and is in pressure contact with the skeleton portion 24. Thereby, in the skeleton part 24 other than the through hole 22 in the synthetic resin sheet 21, the synthetic resin of the synthetic resin sheet enters the porous body 31 and becomes entangled with the porous body 31. The integration of 21 and the porous body 31 becomes strong. On the other hand, in the portion of the through-hole 22 in the synthetic resin sheet 21, the porous body 31 becomes denser and thicker than the skeleton portion 24 other than the through-hole 22.

  After the pressing step, the periphery of the portion formed by the concave mold 57 and the convex mold 59 is cut to obtain the duct half body 11 having a substantially concave cross section. Next, a half body joining step is performed. In the half-body joining step, as shown in FIG. 7, the duct halves 11 are joined and integrated at the flange portion 12 on the side so that the concave surfaces 11a face each other, and are shown in FIG. A duct 10 is obtained. The joint integration is performed by a method of fusing the flange portions 12 by overlapping the flange portions 12 in the two duct halves 11 and pressing them with the hot plate 71.

  The production of the automobile duct is not limited to a method of continuously performing using a continuous production apparatus as shown in FIG. 5, but using a synthetic resin sheet and a porous body cut to a predetermined size, one unit. Or the method of manufacturing by a predetermined number unit may be used.

An example will be specifically described below. A 2 mm thick polyethylene resin synthetic resin sheet (melting point 135 ° C.) in which square through holes of 5 mm × 5 mm are formed at intervals of 7 mm (hole center interval), a basis weight of 50 g / m ² as a porous body, and a thickness of 1 mm Non-woven fabric (PP fiber, melting point 160 ° C.), the heating temperature is 140 ° C., the concave mold is positioned on the lower side, and the convex mold is positioned on the upper side, and the synthetic resin is placed on the porous body. The sheets were stacked and pressed with the concave mold and the convex mold to perform integration and shaping. And the circumference | surroundings of the shaped part were cut | disconnected and the duct half body of cross-sectional substantially concave shape was obtained. Next, the duct halves are overlapped with each other on the side flange portion, and the flange portion is pressed and fused with a hot plate at 180 ° C., and a straight tubular automobile duct having a square cross section of 75 mm × 80 mm and having a length of 600 mm. Manufactured. The obtained automobile duct was lightweight without tearing at the corners.

It is a perspective view which shows the duct for motor vehicles based on one Embodiment manufactured with the manufacturing method of this invention. It is a perspective view which shows a part of duct for motor vehicles of FIG. FIG. 3 is a cross-sectional view taken along the line 3-3 in FIG. 2. It is a perspective view of a synthetic resin sheet and a porous body. It is the schematic of a manufacturing apparatus. It is sectional drawing which shows the time of a press. It is sectional drawing which shows the time of joining of duct halves.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Automotive duct 11 Duct half body 12 Flange part 21 Synthetic resin sheet 22 Through-hole 31 Porous body 55 Heating means 57 Concave type 59 Convex type

Claims (4)

Heat the synthetic resin sheet having a large number of through holes and the porous body,
The synthetic resin sheet and the porous body are stacked and pressed with a concave mold and a convex mold to form a duct half having a substantially concave cross section by integrating and shaping,
A method for manufacturing a duct for an automobile, characterized in that the duct halves are joined to each other at the side so that the concave surfaces are on the inside to form a tube. The synthetic resin sheet has a lower melting point than the porous body,
Place the synthetic resin sheet on the porous body and perform the heating,
The method for manufacturing a duct for an automobile according to claim 1, wherein a heating temperature of the synthetic resin sheet and the porous body is equal to or higher than a melting point of the synthetic resin sheet and lower than a melting point of the porous body. .   During the pressing, the synthetic resin sheet is disposed toward the convex mold and the porous body is disposed toward the concave mold, and the press forms the inner surface of the duct with the synthetic resin sheet. 3. The method of manufacturing an automobile duct according to claim 1, wherein the duct outer surface side is formed of a material.   The press compresses the porous body by pressing against the skeleton portion in the skeleton portion other than the through-holes in the synthetic resin sheet, while the porous body enters the through-holes in the through-hole portions. The automobile according to any one of claims 1 to 3, wherein the degree of compression is lower than that of the portion of the porous body that is in pressure contact with the skeleton portion, or the thickness is increased without compression. Manufacturing method for an automobile.

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