JP2004195838A - Method for molding double-walled pipe member, and double-walled pipe member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double-walled pipe member which shows high torsion rigidity and deflection rigidity and also high mechanical strength, and a method for molding this double-walled pipe member. <P>SOLUTION: This method molds the double-walled pipe member which reinforces a first cylindrical member 11 with a second cylindrical member by injecting a molten resin 27 to the outer peripheral side of the first cylindrical member 11 molded in a resin beforehand, then curing the resin and insert-molding the first cylindrical member 11 inside the second cylindrical member. A boss 14 is formed in the way that it is high enough to come into contact with the inner surface 25 of a mold 21 when closed and becomes one piece with the interior of a cross section orthogonal with the axial direction of the first cylindrical member 11. The second cylindrical member 12 is formed by filling a cavity 26 between the outer peripheral surface of the first cylindrical member 11 and the inner surface 25 of the mold 21 with the molten resin 27 and curing it. Thus the second cylindrical member covers the first cylindrical member 11. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a molding method for molding a double pipe member by insert molding and a double pipe member molded by this method.
[0002]
[Prior art]
Conventionally, a resin-made double pipe member used for automobile parts such as an intake manifold and a radiator hose is formed by, for example, injection molding a molten resin on an outer peripheral side of a first tubular member arranged inside and curing the molten resin. (For example, see Patent Document 1).
[0003]
[Patent Document 1]
JP-A-2000-220598
[Patent Document 2]
Japanese Patent No. 3219407
[Problems to be solved by the invention]
However, in the conventional molding method, since the second tubular member is not provided to reinforce the first tubular member, the strength of the entire double pipe member is not always large. Further, the bonding strength between the first tubular member and the second tubular member is not always large, and there is a possibility that the double pipe member may be twisted or bent when the second tubular member is injection-molded. Was.
[0006]
Therefore, an object of the present invention is to provide a method of forming a double pipe member having a high torsional rigidity and a high bending rigidity, and a large strength of the entire double pipe member, and a double pipe member.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 of the present invention is characterized in that a molten resin is injected into the outer peripheral side of a first cylindrical member formed of a resin in advance and is cured to form a first cylindrical member in a second cylindrical member. In a method of forming a double-pipe member in which the first tubular member is reinforced by the second tubular member by insert-molding the tubular member,
An outer periphery at a position where the first cylindrical member is housed inside the mold and has a height that abuts against the inner surface of the mold when the mold is closed, and is offset from each other in the axial direction of the first cylindrical member. A plurality of bosses are formed on the surface, and the bosses are provided so as to be one in a cross section orthogonal to the axial direction of the first tubular member,
The first cylindrical member is housed in a mold, and the cavity between the outer peripheral surface of the first cylindrical member and the inner surface of the mold is filled with molten resin and cured to form a second cylindrical member. Mold the member,
This is a method of forming a double tube member that covers the first tubular member with the second tubular member.
[0008]
In the invention according to claim 2, the boss is formed in a substantially columnar shape.
[0009]
In the invention according to claim 3, a rib for connecting the plurality of bosses is formed on an outer peripheral surface of the first tubular member.
[0010]
In the invention according to claim 4, the rib is formed to be lower than the height of the boss.
[0011]
The invention according to claim 5 is characterized in that the molten resin is injected and cured on the outer peripheral side of the first cylindrical member molded in advance with resin, and the second cylindrical member is molded. In a double tube member in which a first tubular member is insert-molded in a tubular member,
A plurality of bosses are protruded from an outer peripheral surface of the first cylindrical member toward an inner peripheral surface of the second cylindrical member, and the bosses are mutually disposed in the axial direction of the first cylindrical member. It is provided so as to be one on the outer peripheral surface at the shifted position and in a cross section orthogonal to the axial direction.
【The invention's effect】
According to the invention described in claim 1 of the present invention, since the boss is provided on the outer peripheral surface of the first cylindrical member to abut the inner surface of the mold, the first boss can be used even during the injection of the molten resin. A second cylindrical member in which one cylindrical member does not move in the radial direction can be formed. If the heights of the plurality of bosses are substantially the same, the thickness of the second tubular member can be made uniform. Further, since the strength of the first cylindrical member can be improved by the boss, the first cylindrical member is crushed even when pressure is applied to the first cylindrical member by injection of the molten resin. Thus, a double-pipe member having good quality can be formed without problems such as the above. Furthermore, since the bosses are arranged so as not to be adjacent to each other in the axial direction and at a position shifted from each other in the axial direction of the first tubular member and one in the cross section orthogonal to the axial direction, A double pipe member having high torsional rigidity and high flexural rigidity can be obtained.
[0012]
According to the second aspect of the present invention, when the molten resin flows around the boss when the molten resin is injected, the molten resin can flow smoothly without receiving resistance.
[0013]
According to the third aspect of the present invention, since the strength of the first tubular member can be further improved, even if pressure is applied to the first tubular member by the injection of the molten resin, the first tubular member can be kept in the first tubular member. The problem that the cylindrical member is crushed is eliminated.
[0014]
According to the invention described in claim 4, since a gap is formed between the rib and the inner surface of the mold, when the molten resin is injected, the molten resin flows over the rib and flows smoothly, There is no adverse effect on the molding of the tubular member.
[0015]
According to the invention described in claim 5, the strength of the first tubular member can be improved by the boss. Furthermore, since the bosses are arranged at positions shifted from each other in the axial direction of the first tubular member so that the bosses are not adjacent to each other in the axial direction, it is possible to obtain a double pipe member having high torsional rigidity and flexural rigidity. it can.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings.
[0017]
[First Embodiment]
As shown in FIG. 1, the double pipe member 10 according to the first embodiment is specifically arranged in a vehicle width direction between a lower portion of a front pillar at a front portion of a vehicle cabin and a steering column or an instrument panel (not shown). A first tubular member 11 extending over the entire width in the vehicle width direction in the vehicle interior, and a first tubular member extending from the driver seat side below the front pillar to the vicinity of the steering column arrangement portion. A second cylindrical member 12 for reinforcing and supporting the steering column. As shown in FIG. 2, which is a cross-sectional view taken along line AA in FIG. 1, the first and second cylindrical members 11 and 12 each have an elliptical cross section, and have an outer second cylindrical member. The first cylindrical member 11 is insert-molded inside the cylindrical member 12, and both are fixed to each other.
[0018]
As shown in FIG. 3, the double pipe member 10 includes a lid 13 shown at the left end, the first tubular member 11, and a second tubular member 12. . The second tubular member 12 is configured to be coupled to the first tubular member 11 so as not to come off from the first tubular member 11, but in FIG. For the sake of clarity, the first tubular member 11 and the second tubular member 12 are separately shown for convenience. The first tubular member 11 is connected to an air conditioner (not shown) near the center in the left-right width direction and functions as a duct member that carries air-conditioned air discharged from the air conditioner to the left and right. It has a hollow shape in the vehicle width direction, and holes 18, 12b (17) for blowing out conditioned air into the vehicle interior are formed near the left and right ends thereof. The lid member 13 has a mounting portion 13a fixed to a lower portion of the front pillar on the side of the passenger seat of the vehicle.
[0019]
As shown in the figure, a plurality of bosses 14 are formed at an end portion of the first cylindrical member 11 which is surrounded by the second cylindrical member so as to protrude from an outer surface thereof. The boss 14 is formed in a substantially columnar shape, and extends along the up and down direction so as to come out of the mold when the mold is opened and taken out, as shown in FIG. 6 described later. Further, as shown in FIG. 4, the bosses 14 are arranged at positions displaced from each other in the axial direction of the first tubular member 11 so as to be one each in a radial cross section. That is, in FIG. 4, a broken line indicates a radial cross-sectional position, and only one boss 14 is formed on the broken line.
[0020]
FIG. 5 is an exploded perspective view of the first tubular member 11 of the double pipe member 10 of FIG. The first tubular member 11 is composed of two vertically separated half members 15 and 16 formed of a synthetic resin, and the upper half member 15 has holes at both ends in the axial direction. 17, 18 are drilled. The first tubular member 11 having a hollow portion formed therein is formed by abutting the flange portions 19 and 20 of these two half members 15 and 16 with each other and vibration welding the flange portions 19 and 20. can do.
[0021]
As shown in FIG. 6, a boss 14 extending upward is formed on the outer surface of the upper half member 15. As described above, the boss 14 extends in the vertical direction so as to be easily removed from the mold.
[0022]
On the other hand, the second cylindrical member 12 has an attachment portion 12 a fixed to the lower portion of the front pillar on the vehicle driver's seat side at an end thereof, and corresponds to the hole 17 of the first cylindrical member 11. Opening 12b is formed.
[0023]
Next, a procedure for molding the double pipe member 10 having the above-described configuration will be described.
[0024]
FIG. 7 is a cross-sectional view showing the first tubular member 11 and the inside of the mold 21 that houses the first tubular member 11. The mold 21 includes an upper mold 23 provided with a gate port 22 on the upper surface, and a lower mold 24 provided below the upper mold 23. As shown in the figure, in a state where the first cylindrical member 11 is housed and the mold 21 is closed, only a part of the first cylindrical member 11 on the driver's seat side is housed in the mold 21. The other parts are projected from the mold 21, and the inside of the first tubular member 11 including the part housed in the mold 21 remains hollow. The tip of the boss 14 is in contact with the inner surface 25 of the mold 21. That is, the space between the mold inner surface 25 and the first cylindrical member 11 is the cavity 26, the height of the cavity 26 is the same as the height of the boss 14, and the second cylindrical member It has the same thickness as the member 12.
[0025]
When the second cylindrical member 12 is molded, molten resin 27 reinforced by mixing glass fiber or carbon fiber or the like is injected into the mold 21 from the gate port 22 of the upper mold 23, as shown in FIG. Thus, the molten resin 27 fills the cavity 26 by flowing from the upper side of the cavity 26 toward the lower side. Further, as shown in FIG. 9, since the boss 14 is formed in a substantially columnar shape, the molten resin 27 flows so as to go around the outer periphery of the boss 14 and the inflow resistance can be suppressed.
[0026]
According to the double-pipe member 10 according to the first embodiment, the boss 14 formed at substantially the same height is in contact with the mold inner surface 25, so that the molten resin 27 is injected into the mold 21. In addition, since the first cylindrical member 11 does not move in the radial direction, the plate thickness of the second cylindrical member 12 can be formed to be substantially constant over the entire circumferential direction.
[0027]
In addition, since a plurality of bosses 14 are provided, and the bosses 14 are securely fitted to the second tubular member 12, the torsional rigidity and the bending rigidity with respect to the second tubular member 12 are increased. be able to. Since the boss 14 is formed in a substantially columnar shape, the flowability of the molten resin 27 does not deteriorate, and the boss 14 can efficiently spread to the cavity 26 in the mold 21.
[0028]
The boss 14 is not limited to a substantially columnar shape, and may be formed in a regular polygonal cross section as long as the shape does not increase the flow resistance.
[0029]
According to the first embodiment, the second tubular member 12 that covers the first tubular member 11 is provided to reinforce the first tubular member 11, and particularly has a duct function. In addition, the mechanical strength of only the driver's seat side of the steering member requiring the supporting rigidity can be efficiently improved. Furthermore, even if a fiber-reinforced resin, which is more advantageous in strength than the resin used to form the first tubular member 11, is used, since the reinforcing portion is partial, weight increase and cost increase due to materials are minimized. Can be suppressed.
[0030]
Further, since the boss 14 formed on the outer peripheral surface of the first cylindrical member 11 is engaged with the inner peripheral surface of the second cylindrical member 12, the boss 14 allows the first cylindrical member 11 to be connected to the first cylindrical member 11. The coupling strength with the second tubular member 12 can be improved. The boss 14 also increases the torsional rigidity and the flexural rigidity of the entire double pipe member 10.
[0031]
[Second embodiment]
Next, a double tube member according to a second embodiment will be described. The same parts as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.
[0032]
In the present embodiment, as shown in FIG. 10, bosses 54 and ribs 53 connecting the bosses 54 are formed on the outer surface of the first tubular member 51. The rib 53 connects adjacent bosses 54, 54, and a plurality of triangular areas 55 are formed by these ribs 53. Also, as shown in FIG. 11, the height h of the rib 53 is set lower than the height H of the boss 54, and is approximately half the height of the boss 54.
[0033]
FIG. 12 is a perspective view showing a state in which the molten resin 27 flows outside the first tubular member 51 according to the second embodiment. As shown in the figure, when the rib 53 is formed on the outer surface of the first tubular member 51, the molten resin 27 supplied into the mold 21 from the gate port 22 flows along the rib 53 and , Even if the ribs 53 are passed.
[0034]
Then, as shown in FIG. 13, after the molten resin 27 is cured, a second tubular member 52 is formed outside the first tubular member 51. Thus, the outer surface 51 a of the second tubular member 52 is at the same height position as the tip of the boss 54.
[0035]
As shown in FIG. 14, when the molten resin is injected outside the cylindrical member 60 having no ribs, a molding pressure F is applied to the cylindrical member 60, so that the thickness of the side wall 61 of the cylindrical member 60 is reduced. If the thickness is reduced, it may be crushed inward. However, as shown in FIG. 15, since the first tubular member 51 according to the second embodiment is provided with the rib 53, the rigidity is improved with respect to the molding pressure F from the side. The side wall does not collapse even by the molding pressure F.
[0036]
According to the second embodiment, since the boss 54 and the rib 53 are formed on the outer peripheral side of the first tubular member 51, the torsional rigidity and the flexural rigidity are further increased, and the strength of the entire double pipe member is reduced. It can be further improved.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a double pipe member according to a first embodiment of the present invention.
FIG. 2 is a sectional view taken along line AA of FIG.
FIG. 3 is an exploded perspective view of the double pipe member of FIG. 1;
FIG. 4 is a side view showing an end of the first tubular member.
FIG. 5 is an exploded perspective view of the double tube member of FIG. 3;
FIG. 6 is a sectional view taken along line BB of FIG. 5;
FIG. 7 is a cross-sectional view of the inside of the mold showing a state where the double tube member according to the first embodiment is being formed.
FIG. 8 is a cross-sectional view of the inside of a mold showing a state where the double tube member according to the first embodiment is being formed.
FIG. 9 is a perspective view showing a flow of a molten resin near a boss of a first tubular member.
FIG. 10 is a perspective view showing an end of a first tubular member according to a second embodiment.
FIG. 11 is a perspective view showing the vicinity of a boss of a first tubular member according to a second embodiment.
FIG. 12 is a perspective view showing a flow of a molten resin near a boss of a first cylindrical member according to a second embodiment.
FIG. 13 is a sectional view taken along line CC of FIG. 10;
FIG. 14 is a cross-sectional view of the tubular member when a molten resin is injection-molded on the outer peripheral side of the tubular member without ribs.
FIG. 15 is a cross-sectional view of the tubular member when molten resin is injection-molded on the outer peripheral side of the tubular member provided with ribs.
[Explanation of symbols]
Reference Signs List 10 Double pipe member 11, 51 First tubular member 12, 52 Second tubular member 14, 54 Boss 21 Mold 25 Inner surface 26 Cavity 27 Molten resin 53 Rib

Claims (5)

The molten resin (27) is injected to the outer peripheral side of the first cylindrical member (11, 51) formed of resin in advance, and the first cylindrical member (11, 51) is replaced with the second cylindrical member (12, 51). 52) A method of forming a double pipe member for reinforcing the first tubular member (11, 51) by insert molding in the same.
When the mold (21) is closed, a plurality of pieces are provided on the outer peripheral surface of the first cylindrical member (11, 51) at a height abutting on the mold inner surface (25) and at positions offset from each other in the axial direction of the first cylindrical member (11, 51). A first cylindrical member (11, 51) provided with one boss (14, 54) in a cross section orthogonal to the axial direction is housed in a mold (21), and the first cylindrical member (11, 51) is provided. A second cylindrical member (12, 52) obtained by filling a cavity (26) between the outer peripheral surface of the member (11, 51) and the inner surface (25) of the mold with a molten resin (27) and curing the resin. A method for forming a double-pipe member, characterized by covering the cylindrical member (11, 51). The method according to claim 1, wherein the boss (14, 54) is formed in a substantially cylindrical shape. The double pipe member according to claim 1 or 2, wherein a rib (53) connecting the plurality of bosses (54) is formed on an outer peripheral surface of the first tubular member (51). Molding method. The method according to claim 3, wherein the rib (53) is formed to be lower than the height of the boss (54). By injecting the molten resin (27) to the outer peripheral side of the first cylindrical member (11, 51) molded in advance with resin to form the second cylindrical member (12, 52), the second cylindrical member (12, 52) is formed. In a double pipe member obtained by insert-molding a first tubular member (11, 51) into a tubular member (12, 52),
A plurality of bosses (14, 54) project from the outer peripheral surface of the first cylindrical member (11, 51) so as to face the inner peripheral surface of the second cylindrical member (12, 52). The bosses (14, 54) are provided so as to be one on the outer peripheral surface of the first cylindrical member (11, 51) at a position shifted from each other in the axial direction and in a cross section orthogonal to the axial direction. A double pipe member characterized by the above-mentioned.

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