JP2015000547A - Duct - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a duct which can effectively increase the porosity thereof and can obtain excellent thermal insulation.SOLUTION: A duct 10 has a pair of semi-cylindrical duct half bodies 20A, 20B which are joined together to form a cylindrical shape. The duct half bodies 20A, 20B are resin moldings obtained by blow molding a parison or a plurality of sheets in a molding die, and each have an outer surface part 22 molded into a predetermined shape by a recessed molding surface of the molding die and an inner surface part 23 molded into a predetermined shape by a protruded molding surface of the molding die. In the duct 10, the duct half bodies 20A, 20B are each formed of a hollow resin molding, so that a peripheral wall of the duct 10 can have a hollow structure. Consequently, the porosity of the duct 10 can be increased.

Description

  The present invention relates to a duct, and more particularly to a resin duct with improved heat insulation.

  Conventionally, various techniques have been proposed for resin ducts attached to vehicles and the like (see, for example, Patent Document 1).

  In manufacturing this type of duct, for example, a molding material made of a parison or a plurality of resin sheets is used, and the molding material is sandwiched between a pair of split molds, and the molding material is formed along the molding surface of the split mold By inflating or vacuum suction, a cylindrical duct having a predetermined outer surface shape is formed.

  Further, it is generally performed to obtain a duct made of a foamed molded article by molding the resin while foaming a resin with a foaming agent to improve the heat insulating property of the duct.

  By the way, in recent years, further quality improvement of the duct has been demanded, and a resin-made duct that is more excellent in heat insulation is demanded.

Japanese Patent No. 4406756

  The heat insulating property of the foam molded body increases as the proportion of the air amount (void ratio) in the foam molded body increases. That is, if the expansion ratio is set high, the heat insulating property of the foamed molded product can be further increased. However, when the duct is formed of a foamed molded product, if the foaming ratio is set too high, the following problems occur.

  FIG. 21 is a cross-sectional view of a conventional duct, and FIG. 22 is a cross-sectional view taken along a flange portion of the conventional duct. In each of FIG. 21 and FIG. 22, (a) is a cross-sectional view of a duct formed by ordinary blow molding, and (b) is a cross-sectional view of a duct made of a foam molded body.

  As shown in FIG. 21A, when the duct 200 is formed by normal blow molding, the wall thickness distribution of the peripheral wall of the duct 200 is relatively uniform. On the other hand, as shown in FIG. 21 (b), when the duct 200 is formed by blow molding while foaming the resin, a pinch-off portion provided on the alternate long and short dash line 201 (portion where the parison is sandwiched in the molding die) The meat pool 202 is likely to be generated inside. Further, as shown in FIG. 22 (a), in the flange portion 203 that is compression-molded in the molding die, if the normal blow molding is performed, it is difficult for the meat pool to occur, but as shown in FIG. When the duct 200 is formed by blow molding while foaming the resin, the resin is pushed out to the inner peripheral surface side of the duct 200, so that a larger reservoir 205 may be generated. Such occurrence of the pools 202 and 205 becomes more prominent as the expansion ratio or thickness increases.

  If the expansion ratio is a normal size (for example, about 3 times) or less, a resin relief portion (so-called burr relief) is formed large in the pinch-off portion, or a weir retaining rib for suppressing resin flow is provided. By providing at the base of the flange portion 203, it is possible to effectively prevent the occurrence of the meat pools 202 and 205. However, when the expansion ratio exceeds a normal size (for example, about 3 times), it is difficult to prevent the occurrence of the meat pools 202 and 205. As a result, the variation in the wall thickness becomes large, and there arises a problem that dew condensation is likely to occur in the thin wall portion. Also, if the wall thickness varies greatly, the shape of the inner peripheral surface of the duct 200 will not be stable, and the fitting property with other parts will be reduced, so a seal member (for example, a foamed urethane packing) will be required. As a result, the problem of increased component costs arises.

  As described above, since there is a limit to the size of the expansion ratio, it has been difficult to achieve further improvement in heat insulation of the duct with the conventional molding technique. Therefore, there is a demand for a technique for more effectively increasing the porosity of a resin duct without depending on the expansion ratio.

  This invention is made | formed in view of such a situation, The objective is to provide the duct which can raise a porosity more effectively and can obtain the outstanding heat insulation.

In order to achieve such an object, the present invention is grasped by the following configuration.
(1) The duct of the present invention has a pair of semi-cylindrical duct halves joined to form a tubular shape, and the duct half is a resin molding in which a parison or a plurality of sheets are hollow-molded with a molding die. It is a body, and has an outer surface portion formed by a concave molding surface of the molding die, and an inner surface portion molded by a convex molding surface of the molding die.

  According to this structure, since the duct half body was comprised with the hollow resin molding, the surrounding wall of a duct can be made into a hollow structure. Thereby, the porosity in a duct can be raised effectively and the outstanding heat insulation can be provided to a duct.

  Moreover, since the inner surface portion of the duct half constituting the inner peripheral surface of the duct is molded by the convex molding surface of the molding die, a part having functionality is insert-molded on the inner surface portion of the duct half body, It is possible to assemble with high accuracy after forming by using the uneven portion formed integrally with the inner surface of the duct half. Moreover, the part provided with functionality can also be integrally formed in the inner surface part of a duct half body.

(2) The duct according to the present invention is characterized in that, in the configuration of (1), the duct half is a foam molded body formed by foaming a resin with a foaming agent.

  According to this configuration, since the porosity is further increased by configuring the duct with the foamed molded body, the heat insulating property of the duct can be further increased.

  Further, since the inner surface of the duct half is formed by the convex molding surface of the molding die, the thickness can be made uniform, and the shape of the inner peripheral surface of the duct is stabilized. Therefore, it is possible to mold the resin molded body at a higher foaming ratio than before, and a seal member (for example, a foamed urethane packing) for improving the fitting property with other parts becomes unnecessary.

  Further, in the conventional blow molding, when molding a resin molded body with a high expansion ratio, it is necessary to ensure a long cooling time (molding cycle). Since it is in contact with the mold, the inner surface of the duct half can be effectively cooled by the molding die. Therefore, the molding cycle can be shortened, and productivity can be improved.

(3) The duct according to the present invention is configured such that, in the configuration of (1) or (2), one set of the joint surfaces of the pair of duct halves to be joined can be rotated. It has a hinge part to connect, and a pair of said duct half and said hinge part are formed by one, It is characterized by the above-mentioned.

  According to this structure, a pair of duct half body can be easily match | combined by rotating one duct half body to the other duct half body centering on a hinge part. Further, since the pair of duct halves and the hinge portion are integrally molded, the number of parts, the number of molding dies, and the manufacturing process can be reduced.

(4) The duct of the present invention has an engaging portion that engages the other joint surfaces among the two joint surfaces of the pair of duct halves to be joined in the configuration of (3). The pair of duct halves, the hinge portion, and the engagement portion are integrally formed.

  According to this configuration, after the pair of duct halves are combined by the hinge portion, the joining surfaces of the other set can be engaged by the engaging portion, so that the assembly workability of the duct is improved. Moreover, since the pair of duct halves, the hinge portion, and the engaging portion are integrally molded, the number of parts, the number of molding dies, and the manufacturing process can be further reduced.

(5) In the duct of the present invention, in the configuration of (4), the engaging portion also serves as an attachment bracket for attaching the pair of joined duct halves to an attachment target.

  According to this configuration, since the engaging portion and the mounting bracket are used together, the number of parts can be further reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the porosity which can raise a porosity more effectively and can obtain the outstanding heat insulation can be provided.

It is a perspective view of the duct of a 1st embodiment concerning the present invention. It is a disassembled perspective view of the duct shown by FIG. It is a figure which shows the structural example of the duct shown by FIG. 1, (a) is sectional drawing of the structural example 1, (b) is sectional drawing of the structural example 2, (c) is sectional drawing of the structural example 3, (d ) Is a diagram of Configuration Example 4 viewed from the axial direction. It is a figure explaining the shaping | molding method 1, (a) is a horizontal sectional view of the shaping die in a mold open state, (b) is a horizontal sectional view of the shaping die in a clamping state. It is a figure explaining the shaping | molding method 2, (a) is a horizontal sectional view of the shaping die in a mold open state, (b) is a horizontal sectional view of the shaping die in a clamping state. It is a figure explaining the shaping | molding method 3, (a) is a horizontal sectional view of the shaping die in a mold open state, (b) is a horizontal sectional view of the shaping die in a clamping state. It is a figure explaining the shaping | molding method 4, (a) is a horizontal sectional view of the shaping die in a mold open state, (b) is a horizontal sectional view of the shaping die in a clamping state. It is a figure explaining the shaping | molding method 5, (a) is a horizontal sectional view of the molding die of a mold open state, (b) is a horizontal sectional view of the molding die of a mold clamping state. It is a figure explaining the joining method of a pair of duct half body, (a) is a figure explaining a heating process, (b) is a figure explaining a bending process, (c) is a modified example of (b). FIG. It is a figure explaining the engagement example 1 of a pair of duct half body. It is a figure explaining the engagement example 2 of a pair of duct half body. (A) is a figure explaining the engagement example 3 of a pair of duct half body, (b) is the sectional view on the AA line of (a). It is the figure which looked at the duct of 2nd Embodiment from the axial direction. It is a figure explaining the duct of 3rd Embodiment, (a) is a change figure of Fig.3 (a), (b) is a change figure of FIG.3 (b), (c) is a change of FIG.3 (c). FIG. 4D is a modified view of FIG. It is a perspective view of the duct of a 3rd embodiment. (A) is a view from arrow B in FIG. 15, (b) is a view from arrow C in (a), and (c) is a view from arrow D in (a). It is a perspective view of the duct of 4th Embodiment. It is a top view of the duct half body shown by FIG. It is a figure explaining the shaping | molding method 6, (a) is a vertical sectional view of the shaping die in a mold open state, (b) is a vertical sectional view of the shaping die in a clamping state. It is a figure explaining the shaping | molding method 7, (a) is a vertical sectional view of the molding die in the mold open state, (b) is a vertical sectional view of the molding die in the mold clamped state. It is sectional drawing of the conventional duct, (a) is sectional drawing of the duct shape | molded by uniform thickness, (b) is sectional drawing of the duct consisting of a foaming molding. It is sectional drawing which cut | disconnected the conventional duct by the flange part, (a) is sectional drawing of the duct shape | molded by uniform thickness, (b) is sectional drawing of the duct which consists of a foaming molding.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as “embodiments”) will be described in detail with reference to the accompanying drawings. The same number is attached | subjected to the same element through the whole description of embodiment. The duct of the present invention is obtained by hollow-molding at least one duct half. In the following description, an example in which two solid duct halves are joined (Configuration Example 3, molding methods 2 and 3). 7) is also described as a reference example.

(First embodiment)
First, the basic structure of the duct 10 of 1st Embodiment is demonstrated based on FIG. 1, FIG.
As shown in FIG. 1, the duct 10 has a cylindrical shape (in this example, a cylindrical shape), and includes a cylindrical outer peripheral surface 11 and a cylindrical inner peripheral surface 12. In addition, the cross-sectional shape of the duct 10 can be selected from various shapes such as an elliptical shape, a rectangular shape, and a polygonal shape in addition to a circular shape.

  The duct 10 can be used as an air conditioning duct that is attached to, for example, a component constituting a vehicle and forms a passage for introducing air from the outside to the inside of the passenger compartment. The components can be arbitrarily selected from various interior materials for interiors such as a roof trim, door trim, and instrument panel, and various body panels for forming the interior such as roof panels and door panels. The duct of the present invention is applicable to various ducts that form fluid flow paths in addition to such an air conditioning duct for vehicles.

  As shown in FIG. 2, the duct 10 includes a pair of semi-cylindrical (in this example, semi-cylindrical) duct halves 20A and 20B, the pair of duct halves 20A and 20B face each other, and Two sets of joining surfaces 21A and 21B are joined to form a cylindrical shape.

  The duct halves 20A and 20B are resin moldings molded by a molding die 30 (see FIGS. 4 and 5), and have a semi-cylindrical outer surface portion 22 and a semi-cylindrical inner surface portion 23. The outer surface portion 22 is molded into a predetermined shape by a concave molding surface 42 (see FIGS. 4 and 5). The inner surface portion 23 is also molded into a predetermined shape with a convex molding surface 52 (see FIGS. 4 and 5).

As the constituent material of the duct halves 20A and 20B, a thermoplastic resin can be mainly used. As the thermoplastic resin, a polyolefin resin is preferable, and as the polyolefin resin, for example, a melt tension at 230 ° C. is 30. Polypropylene in the range of ~ 350 mN is used. As polypropylene, a propylene homopolymer, an ethylene-propylene block copolymer, an ethylene-propylene random copolymer, and a mixture thereof can be used. Further, it is preferable to add a styrene-based elastomer or low-density polyethylene in a range of less than 40 wt% with respect to the polyolefin-based resin. As the styrene-based elastomer, hydrogenated polymers such as styrene-ethylene / butylene-styrene block copolymer, styrene-ethylene / propylene-styrene block copolymer, styrene-butadiene random copolymer, etc. are used. The content is preferably less than 30 wt%. Further, as the low density polyethylene, those having a density of 0.91 g / cm ³ or less are used, and it is particularly preferable to use a linear ultra low density polyethylene polymerized by a metallocene catalyst.

  Further, the duct halves 20A and 20B can be formed of a foamed molded body formed by foaming a resin with a foaming agent. In this case, as the foaming agent, any of a physical foaming agent, a chemical foaming agent and a mixture thereof can be used. May be used. As physical foaming agents, inorganic physical foaming agents such as air, carbon dioxide, nitrogen gas, and water, and organic physical foaming agents such as butane, pentane, hexane, dichloromethane, dichloroethane, and their supercritical fluids are used. be able to. As the supercritical fluid, carbon dioxide, nitrogen or the like is preferably used. If nitrogen is used, the critical temperature is 149.1 ° C. and the critical pressure is 3.4 MPa or more. If carbon dioxide is used, the critical temperature is 31 ° C. and the critical pressure is 7 It is obtained by setting it to 4 MPa or more.

(Configuration example of duct 10)
Next, specific configuration examples 1 to 4 of the duct 10 will be described with reference to FIG. In addition, the shaping | molding method of these structural examples 1-4 is mentioned later.

(Configuration example 1)
As shown in FIG. 3A, in the configuration example 1, the duct halves 20A and 20B are formed of a hollow molded resin molded body, and the outer surface portion 22 and the inner surface portion 23 are provided inside the duct halves 20A and 20B. A hollow portion 25 is formed along Of the two pairs of joining surfaces 21A and 21B of the pair of duct halves 20A and 20B to be joined, one set of joining surfaces 21A and 21B is pivotally connected by a hinge portion 26. The hinge portion 26 may be a part integrally formed with the duct halves 20A and 20B or a part different from the duct halves 20A and 20B. In this example, both of the pair of duct halves 20A and 20B are formed into a hollow structure, but only one of the pair of duct halves 20A and 20B may have a hollow structure.

(Configuration example 2)
As shown in FIG. 3B, in the configuration example 2, the reinforcing ribs 27 that are recessed from the outer surface portion 22 to the inner surface portion 23 side are provided on the duct halves 20A and 20B of the configuration example 1 (see FIG. 3A). Mold. With this reinforcing rib 27, it is possible to suppress a decrease in rigidity due to the hollow structure of the duct halves 20A and 20B and deformation due to thermal contraction. The shape of the reinforcing rib 27 can be selected from arbitrary shapes, and the width, length, and number are also arbitrary. The reinforcing rib 27 may be formed on at least one of the duct halves 20A and 20B.

(Configuration example 3)
As shown in FIG.3 (c), in the structural example 3, duct half body 20A, 20B is comprised with a solid resin molding. Also in this structural example 3, one pair of joint surfaces 21A and 21B among the two pairs of joint surfaces 21A and 21B of the pair of duct halves 20A and 20B to be joined is rotatably connected by the hinge portion 26. Is possible.

(Configuration example 4)
As shown in FIG. 3D, in the configuration example 4, the pair of duct halves 20A and 20B are individually formed without being connected by the hinge portion. The sectional shape of each of the duct halves 20A and 20B can be selected from Configuration Examples 1 to 3 (see FIGS. 3A to 3C).

(Method of forming duct 10)
Then, the shaping | molding methods 1-5 of the duct 10 of 1st Embodiment are demonstrated based on FIGS.

(Molding method 1)
As shown to Fig.4 (a), the shaping | molding method 1 is a method of carrying out the hollow shaping | molding of the said structural examples 1 and 2 (refer FIG.3 (a), (b)), for example, and a foaming agent is added. The parison 31 which melt | dissolved the made thermoplastic resin and the shaping | molding die 30 which shape | molds this parison 31 in a predetermined shape are used.

  The molding die 30 is composed of a first split die 40 and a second split die 50 that are combined with each other, and the first split die 40 and the second split die 50 are arranged with the parison 31 therebetween. The first split mold 40 is provided with a blow pin 32. Each of the first split mold 40 and the second split mold 50 is provided with a first molding surface 41 and a second molding surface 51.

  The first molding surface 41 includes two concave molding surfaces 42 and a first crushing portion 43 formed between the two concave molding surfaces 42. In addition, an annular first pinch-off portion 45 that surrounds the two concave molding surfaces 42 is provided on the outer periphery of the first split mold 40.

  On the other hand, the second molding surface 51 includes two convex molding surfaces 52 and a second crushing portion 53 formed between the two convex molding surfaces 52. In addition, an annular second pinch-off portion 55 that surrounds the two convex molding surfaces 52 is provided on the outer peripheral portion of the second split mold 50.

  In this molding method 1, first, a thermoplastic resin to which a foaming agent has been added is kneaded with an extruder (not shown), and then the molten cylindrical parison 31 is extruded from a die slit (not shown) to open the mold. The first split mold 40 and the second split mold 50 are clamped by hanging between the split mold 40 and the second split mold 50.

  Then, as shown in FIG. 4B, air is blown from the blow pins 32 to inflate the parison 31, and the duct halves 20A and 20B are hollow-molded along the concave molding surface 42 and the convex molding surface 52. At the same time, the first crushing portion 43 and the second crushing portion 53 are compression-molded with the parison 31 interposed therebetween, and the hinge portion 26 is molded. Thereby, the foaming molding of the duct 10 by which a pair of duct half body 20A, 20B provided with the hollow part 25 and the hinge part 26 were integrally molded is obtained. This foamed molded article is a burr (not required) outside the first pinch-off part 45 and the second pinch-off part 55 after the first split mold 40 and the second split mold 50 are opened and removed from the molding die 30. Part) is removed.

  When only one of the pair of duct halves 20A and 20B (for example, the duct half 20A) is hollow-molded, the other (for example, the duct halves 20B) is solid like the hinge portion 26 by compression molding. Can be formed into a simple structure.

(Molding method 2)
As shown in FIGS. 5A and 5B, the molding method 2 is, for example, a method of molding the duct 10 of the configuration example 3 (see FIG. 3C). The parison 31 is compression molded between the first molding surface 41 and the second molding surface 51 by setting the clearance 33 between the first molding surface 41 and the second molding surface 51 narrow. Thereby, the foaming molding of the duct 10 in which the pair of solid duct halves 20A and 20B and the hinge part 26 are integrally molded is obtained.

  For the duct halves 20A and 20B shown in the configuration example 4 (see FIG. 3D), the pair of duct halves 20A and 20B are respectively molded using a molding die having a structure in which the hinge portion is not molded. Alternatively, the pair of duct halves 20A and 20B can be obtained by molding in separate steps.

(Molding method 3)
As shown in FIG. 6A, in the molding method 3, a vacuum means 58 having a vacuum suction air passage 57 that forms a recess 56 on the convex molding surface 52 and communicates with the recess 56. Provided in the split mold 50. As a result, as shown in FIG. 6 (b), the air passage 57 is vacuumed to form the parison 31 along the recess 56, and the protrusions 28 are integrally formed on the inner surface portion 23 of the duct halves 20A and 20B. can do. Such a protrusion 28 can be configured as a functional unit having a rectifying function and a sound absorbing function.

(Molding method 4)
Further, as in the molding method 4 shown in FIGS. 7A and 7B, the projection 28 molded by the recess 56 can be configured in a hollow structure.

(Molding method 5)
The molding of the duct 10 is not particularly limited to the molding method using the parison 31 as a molding material. For example, instead of the cylindrical parison 31, a plurality of molten sheets are arranged between a pair of divided molds, and a sealed space between the plurality of sheets and the divided molds is sucked. A resin molded body having a hollow portion between a plurality of sheets may be molded. Alternatively, a solid resin molded body may be formed by vacuum forming or pressure forming one or more molten sheets on one split mold side.

  For example, as shown in FIG. 8A, in the molding method 5, a vacuum means 58 having a vacuum suction air passage 57 that forms a concave portion 56 on a convex molding surface 52 and communicates with the concave portion 56. The second split mold 50 is provided. The first split mold 40 is also provided with a vacuum means 58 provided with an air passage 57 for vacuum suction that communicates with the concave molding surface 42. Furthermore, two resin sheets 35 in a molten state are used instead of the parison. As a result, as shown in FIG. 8B, the air passage 57 is vacuum-sucked, so that two sheets 35 are hollow-formed along the concave molding surface 42 and the convex molding surface 52, and at the same time the duct A protrusion 28 having functionality can be integrally formed on the inner surface portion 23 of the half bodies 20A and 20B.

(Method of joining the duct halves 20A and 20B)
Next, a method of joining the pair of duct halves 20A and 20B in the above configuration examples 1 to 4 (see FIGS. 3A to 3D) will be described based on FIG.

  The method of joining two sets of joining surfaces 21A and 21B of the duct halves 20A and 20B can be selected from various methods. For example, as shown in FIG. 9A, a total of four joining surfaces 21A and 21B are heated by a hot plate 61 and the like in a state where the pair of duct halves 20A and 20B are developed. And a pair of duct half bodies 20A and 20B are made to oppose, and two sets of joining surfaces 21A and 21B are heat-welded. In the case of having the hinge portion 26 as in the above configuration examples 1 to 3 (see FIGS. 3A to 3C), as shown in FIG. 9B, one duct is formed while the hinge portion 26 is bent. The half body 20A is rotated to the other duct half body 20B side and heat-welded. Further, instead of such heat welding, two sets of joining surfaces 21A and 21B may be welded together using vibration welding. Furthermore, when high bonding strength is required, it is also effective to increase the bonding area by forming the bonding surfaces 21A and 21B in a flange shape as shown in FIG. 9C.

(Example of engagement of duct halves 20A and 20B)
Next, in the above configuration examples 1 to 4 (see FIGS. 3A to 3D), engagement examples 1 to 3 that engage the pair of duct halves 20A and 20B are based on FIGS. explain.

(Example of engagement 1)
The two joining surfaces 21A and 21B of the duct halves 20A and 20B may be engaged by various mechanical elements in addition to being joined by the joining method (see FIG. 9).

  As shown in FIG. 10, in the engagement example 1, of the two sets of joining surfaces 21A and 21B, the other set of joining surfaces 21A and 21B is configured by an engaging portion 62 formed into a flange shape. Then, the two overlapping engaging portions 62 are fastened with various fastening members along the direction indicated by the alternate long and short dash line 63. As the fastening member, a screw member, a rivet, a tucker, or the like can be used.

(Example of engagement 2)
As shown in FIG. 11, in the engagement example 2, the flange-shaped mounting bracket 65 is formed as the engaging portion 62, and these two mounting brackets 65 are overlapped. Then, the overlapped mounting bracket 65 is attached to an attachment target of the duct 10 (for example, a vehicle component) with various fastening members.

(Example 3 of engagement)
As shown in FIG. 12A, in the engagement example 3, for example, the recess 66 is formed on the joining surface 21B of the duct half 20B, and the recess 66 can be fitted to the joining surface 21A of the duct half 20A. A convex portion 67 is formed. According to this configuration, the joining surfaces 21A and 21B can be engaged with each other without using fastening parts. Further, as shown in FIG. 12B, the concave portion 66 and the convex portion 67 may be molded over the entire axial direction of the duct 10, or may be partially shortened, and can be selected from various forms. is there.

  In addition, in one duct 10, the engagement examples 1 to 3 may be provided in an appropriate combination, and the combination is arbitrary. In addition, if the joining surfaces 21A and 21B are engaged with each other only by the engagement examples 1 to 3 without welding, the equipment cost of the welding machine or the like can be suppressed.

(Effect of 1st Embodiment)
The effects of the duct 10 described above will be described.
By forming the duct halves 20A and 20B with a hollow resin molded body, the peripheral wall of the duct 10 can have a hollow structure. Thereby, the porosity in the duct 10 can be increased more effectively, and excellent heat insulating properties can be imparted to the duct 10.

  In addition, since the inner surface portion 23 of the duct halves 20A and 20B constituting the inner peripheral surface 12 of the duct 10 is formed by the convex molding surface 52 of the molding die 30, a component having functionality is provided as the duct half 20A. , 20B can be insert-molded on the inner surface portion 23 of the duct half body 20A, 20B. Moreover, the part (protrusion 28 etc.) provided with functionality can also be integrally molded in the inner surface part 23 of duct half body 20A, 20B. In addition, the structure using this effect is illustrated in 2nd Embodiment and 3rd Embodiment mentioned later.

  Moreover, the heat insulation of the duct 10 can be further improved by comprising the duct 10 with a foaming molding.

  In addition, since the inner surface portion 23 of the duct halves 20A and 20B is formed by the convex molding surface 52 of the molding die 30, the thickness can be made uniform, and the shape of the inner peripheral surface 12 of the duct 10 is also stabilized. . Therefore, it is possible to mold the resin molded body at a higher foaming ratio than before, and a seal member (for example, a foamed urethane packing) for improving the fitting property with other parts becomes unnecessary.

  Further, in the conventional blow molding, when molding a resin molded body at a high expansion ratio, it is necessary to ensure a long cooling time (molding cycle). However, in the duct halves 20A and 20B, the inner surface portion 23 is molded. Since it is in contact with the mold 30, the inner surface portion 23 can be effectively cooled by the molding mold 30. Therefore, the molding cycle can be shortened, and productivity can be improved.

  Further, by turning one duct half 20A toward the other duct half 20B around the hinge portion 26, the pair of duct halves 20A and 20B can be easily combined. Further, if the pair of duct halves 20A and 20B and the hinge portion 26 are integrally molded, the number of parts, the number of molding dies, and the manufacturing process can be reduced.

  In addition, if the pair of duct halves 20A and 20B are combined by the hinge portion 26 and then the other pair of joining surfaces 21A and 21B are engaged by the engaging portion 62, the assembly workability of the duct 10 is improved. Further, if the pair of duct halves 20A and 20B, the hinge part 26, and the engaging part 62 are integrally formed, the number of parts, the number of molding dies, and the manufacturing process can be further reduced. Furthermore, if the engaging portion 62 and the mounting bracket 65 are used together, the number of parts can be further reduced.

(Second Embodiment)
Then, the duct 10 of 2nd Embodiment is demonstrated based on FIG.
As described in the effect of the first embodiment, in the configuration examples 1 to 4 (see FIGS. 3A to 3D), functional parts can be assembled to the inner peripheral surface 12 of the duct 10.

  For example, as shown in FIG. 13, in the second embodiment, the rectifying mesh 71 that rectifies the fluid flowing in the duct 10 is formed on the inner peripheral surface 12 of the duct 10 by using an uneven portion formed integrally with the inner surface portion 23. Provided.

  According to the second embodiment, the rectifying mesh 71 is fitted to the inner surface portion 23 of the duct halves 20A and 20B that are molded with high accuracy by the convex molding surface 52 (see FIGS. 4 to 8). be able to. That is, the rectifying mesh 71 can be accurately and reliably assembled to the inner peripheral surface 12 of the duct 10, and new functionality can be imparted to the duct 10.

(Third embodiment)
Next, the duct 10 of 3rd Embodiment is demonstrated based on FIGS. 14-16.
As described in the effect of the first embodiment, in the configuration examples 1 to 4 (see FIGS. 3A to 3D), a portion having functionality may be integrally formed on the inner peripheral surface 12 of the duct 10. it can.

  For example, as shown in FIGS. 14A to 14D, in the third embodiment, in the configuration examples 1 to 4 (see FIGS. 3A to 3D), the fluid flowing in the duct 10 is allowed to flow. A rectifying plate portion 72 for rectifying is provided on the inner surface portion 23 of the duct halves 20A and 20B. As shown in FIG. 15, a pair of the rectifying plate portions 72 are provided on the inner peripheral surface 12 of the duct 10, and the pair of rectifying plate portions 72 are opposed to each other with the axis 73 of the duct 10 interposed therebetween, and are spiral. Shape. As shown in FIGS. 16A to 16C, the pair of rectifying plate portions 72 are arranged so as to intersect when viewed from the direction perpendicular to the axis of the duct 10, and around the axis 73 of the duct 10. The shape is inverted 180 °. Such a rectifying plate portion 72 is formed integrally with the inner surface portion 23 of the duct halves 20A and 20B by providing a portion for forming the rectifying plate portion 72 on the convex forming surface 52 (see FIGS. 4 to 8). can do.

  According to the third embodiment, new functionality can be imparted to the duct 10 by integrally forming the rectifying plate portion 72 on the inner surface portion 23 of the duct halves 20A and 20B.

(Fourth embodiment)
Next, the duct 80 of the fourth embodiment will be described with reference to FIGS.
In the first to third embodiments, the linear duct 10 is illustrated, but the present invention can also be applied to a curved or bent duct.

  For example, as shown in FIG. 17, the duct 80 of the fourth embodiment has a plurality of bent portions (in this example, two bent portions that bend substantially at a right angle) 81. The duct 80 includes an outer peripheral surface 82 and an inner peripheral surface 83, and the inner peripheral surface 83 forms a fluid flow path that bends in a substantially U shape. The duct 80 is composed of a pair of semi-tubular duct halves 90A and 90B, the pair of duct halves 90A and 90B are opposed to each other, and the inner joint surfaces 91P and the outer joint surfaces are arranged. By joining 91Q, it forms the cylinder shape which curves in a substantially U shape. In the following description, when the duct halves 90A and 90B are collectively referred to, “duct half halves 90” are described as necessary.

  As shown in FIG. 18, the duct half 90 is formed in a substantially U shape along an inner peripheral surface 83 (see FIG. 17) that is a flow path. The duct half body 90 is a resin molded body molded by the molding dies 100 and 130 (see FIGS. 19 and 20), and includes a semi-cylindrical outer surface portion 92 and an inner surface portion 93 that are bent in a substantially U shape. Have.

(Method of forming duct 80)
Subsequently, molding methods 6 and 7 of the duct 80 according to the fourth embodiment will be described with reference to FIGS. 19 and 20.

(Molding method 6)
As shown in FIG. 19A, the molding method 6 is a method of molding the duct half body 90 by blow molding, and a parison 101 in which a thermoplastic resin to which a foaming agent has been added is melted, and the parison 101 is predetermined. And a molding die 100 which is molded into the shape. The molding die 100 includes a first split mold 110 and a second split mold 120 that are combined with each other, and the first split mold 110 and the second split mold 120 are arranged with the parison 101 interposed therebetween. The first split mold 110 is provided with a plurality of blow pins 102. Each of the first split mold 110 and the second split mold 120 is provided with a first molding surface 111 and a second molding surface 121.

  The first molding surface 111 is a portion for molding the outer surface portion 92 (see FIG. 18) of the duct half 90 and surrounds the concave molding surface 112 formed in a substantially U shape, and the concave molding surface 112. And an annular first pinch-off portion 115.

  On the other hand, the second molding surface 121 is a portion that molds the inner surface portion 93 (see FIG. 18) of the duct half 90, and has a convex molding surface 122 formed in a substantially U shape, and this convex molding. And an annular second pinch-off portion 125 surrounding the surface 122.

  In the molding method 6, first, a thermoplastic resin to which a foaming agent has been added is kneaded with an extruder (not shown), and then the molten cylindrical parison 101 is extruded from a die slit (not shown), and the mold is opened. The first divided mold 110 and the second divided mold 120 are clamped by hanging between the mold 110 and the second divided mold 120.

  Next, as shown in FIG. 19B, air is blown from the blow pin 102 to inflate the parison 101, and the substantially half U-shaped duct half body 90 is formed along the concave molding surface 112 and the convex molding surface 122. Hollow molding. At the same time, the parison 101 is crushed by the first pinch-off part 115 and the second pinch-off part 125. Thereby, the foaming molding of the substantially U-shaped duct half body 90 provided with the hollow part 95 is obtained. This foamed molded article is a burr (unnecessary) outside the first pinch-off part 115 and the second pinch-off part 125 after the first split mold 110 and the second split mold 120 are opened and removed from the molding die 100. Portion) and the tip portion 85 (see FIG. 18) of the duct half 90 are cut away.

  Then, two duct halves 90 manufactured in this way are formed, the two duct halves 90A and 90B are made to face each other, and the inner joint surfaces 91P (see FIG. 18) and the outer joint surfaces 91Q are formed. By joining each other (see FIG. 18), it is possible to obtain a duct 80 (see FIG. 17) that is bent in a substantially U shape and has a hollow peripheral wall.

(Molding method 7)
As shown in FIG. 20A, the molding method 7 is a method of molding the duct half 90 by vacuum molding and pressure molding, and a sheet 131 obtained by melting a thermoplastic resin to which a foaming agent is added, and this sheet. A molding die 130 that molds 131 into a predetermined shape is used. The molding die 130 includes a first split mold 140 and a second split mold 150 that are combined with each other, and the first split mold 140 and the second split mold 150 are arranged with the sheet 131 interposed therebetween. The layer configuration of the sheet 131 may be a single layer or a multilayer.

  The first split mold 140 is a mold having a compressed air means 141, and includes a concave molding space 142 formed in a substantially U shape, and an annular first pinch-off portion 143 that surrounds the concave molding space 142. . The compressed air means 141 includes a concave molding space 142 and a pneumatic air passage 145 that is connected to an air pressure source and supplies pressurized air to the concave molding space 142.

  On the other hand, the second split mold 150 is a mold having a vacuum means 151, and has a convex molding surface 152 formed in a substantially U shape. The vacuum means 151 has an air passage 155 for vacuum suction that is connected to a vacuum pump or the like and opens to the convex molding surface 152.

  In the molding method 7, first, the sheet 131 is disposed between the first split mold 140 and the second split mold 150 that are opened, and the first split mold 140 and the second split mold 150 are clamped.

  Next, as shown in FIG. 20B, the sheet 131 is vacuum-formed in the second split mold 150 by the vacuum means 151, and the sheet 131 is pressure-formed in the first split mold 140 by the pressure means 141. As a result, the sheet 131 is formed along the convex forming surface 152, and the substantially U-shaped duct half 90 is formed. At the same time, the sheet 131 is crushed by the first pinch-off portion 143. Thereby, the foaming molding of the duct half 90 which is substantially U-shaped and solid is obtained. The foamed molded article is formed by opening the first split mold 140 and the second split mold 150 and removing them from the molding die 130, and then burrs (unnecessary parts) outside the first pinch-off part 143, and the duct half. The distal end portion 85 (see FIG. 18) of the body 90 is excised.

  Then, two duct halves 90 manufactured in this way are formed, the two duct halves 90A and 90B are made to face each other, and the inner joint surfaces 91P (see FIG. 18) and the outer joint surfaces 91Q are formed. By joining each other (see FIG. 18), it is possible to obtain a duct 80 (see FIG. 17) that is bent in a substantially U shape and has a solid peripheral wall.

  As mentioned above, although this invention was demonstrated using embodiment, it cannot be overemphasized that the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiments. Further, it is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Duct 20A Duct half body 20B Duct half body 21A Joining surface 21B Joining surface 22 Outer surface part 23 Inner surface part 26 Hinge part 30 Molding die 31 Parison 35 Sheet 42 Concave molding surface 52 Convex molding surface 62 Engagement part 65 Attachment Bracket 80 Duct 90 Duct half 90A Duct half 90B Duct half 91P Joint surface 91Q Joint surface 92 Outer surface 93 Inner surface 100 Molding die 101 Parison 112 Concave molding surface 122 Convex molding surface 130 Molding die 131 Sheet 152 Convex molding surface

Claims (5)

Having a pair of semi-cylindrical duct halves joined together to form a cylinder,
The duct half is
A resin molded body in which a parison or a plurality of sheets is hollow-molded by a molding die, and is molded by an outer surface portion molded by a concave molding surface of the molding die and a convex molding surface of the molding die. An inner surface part,
A duct characterized by that. The duct half is
It is a foamed molded product molded by foaming a resin with a foaming agent.
The duct according to claim 1. Of the two sets of joint surfaces of the pair of duct halves to be joined, a hinge portion that rotatably couples one set of joint faces,
The pair of duct halves and the hinge portion are integrally molded.
The duct according to claim 1 or 2, characterized by the above-mentioned. Of the two sets of bonding surfaces of the pair of duct halves to be bonded, the other set has an engaging portion that engages the bonding surfaces with each other,
The pair of duct halves, the hinge portion, and the engagement portion are integrally molded.
The duct according to claim 3. The engaging portion is
Also serves as a mounting bracket for mounting the pair of joined duct halves to the mounting target,
The duct according to claim 4.

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