JPH09226468A - Manufacture of roof rack for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a molding property and rigidity of a roof rack by integrating a main body member and a leg part together. SOLUTION: A terminal of a hollow central main body member 1 provided with a plug member 2 and a mounting tool 6 are arranged in molding dies 7, 8, and a leg part is molded by injecting a synthetic resin 3a into a cavity space 10 inside the molding dies 7, 8. In injection of the synthetic resin 3a, the synthetic resin 3a is prevented from flowing into the inside of a central main body part member 1 by means of the plug member 2, and the leg part and the plug member 2 are firmly connected to the central main body member 1 when the synthetic resin 3a is hardened in engaging parts 1e, 2e, 2g, 5 and the like, so that rigidity of a roof rack is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a roof rack for a vehicle, which is mounted for loading luggage on the roof of a vehicle.

[0002]

2. Description of the Related Art Among conventional roof racks for vehicles, there are, for example, Japanese Utility Model Laid-Open No. 6-67194 and Japanese Patent Laid-Open No. 6-1714.
As disclosed in Japanese Laid-Open Patent Publication No. 32 and the like, there is known a three-body structure including a rack main body which substantially bears a vertical load applied to a roof rack and two legs connected to both ends of the rack main body. ing.

Further, as shown in Japanese Utility Model Laid-Open No. 6-74505, there is known a bulge-molded leg portion at both ends of a rack body.

[0004]

However, in the former three-part type, the legs are inserted into the rack body as separate parts from the rack body, so that the joint is easily rattled and the strength is high. Not only does it fall, but the legs are solid and heavy, and it looks bad.

Further, due to an error between the front and rear mounting surfaces of the roof, the joint portion between the leg portion and the rack body is easily bent, and there is a disadvantage that rigidity is lacking.

Further, it is undeniable that the bulge molding of the legs as in the latter case has poor moldability and is disadvantageous in terms of cost.

Therefore, the present invention provides a method for manufacturing a roof rack for a vehicle, in which the main body member and the legs are integrally formed to improve the rigidity, and the moldability is good and the roof rack can be obtained at a cost advantage. Is what you are trying to do.

[0008]

According to a first aspect of the present invention, there is provided a method of manufacturing a roof rack which is mounted on a roof surface of a vehicle by a leg portion provided at a longitudinal end of a long central body member made of metal. And is formed in a hollow shape having substantially the same cross-sectional shape along the longitudinal direction, and is cut into a predetermined length having rigidity that substantially bears a vertical load applied to the roof rack when mounted on the roof. A central main body member, a bottomed substantially cylindrical bottom wall portion that closes the cavity in the longitudinal direction, and a side wall portion that faces the inner surface of the central main body member. A plug member fixed by being inserted by a predetermined distance is provided, and an engaging portion engageable with a leg portion is formed on one or both of the central body member and the plug member, and the plug member is fixed. At least the terminal of the central body member -A mounting tool for mounting the rack on the roof surface is placed inside an injection molding mold consisting of a cavity mold and a core mold that can be opened and closed on the dividing surface, and when the mold is clamped, the cavity mold By injecting and filling a liquid synthetic resin into a cavity space formed by the mold surface of the core mold and the cylindrical inner surface of the plug member inserted and fixed in the central body member, the leg portion is formed, At least a part of the fixture is integrally fixed by a synthetic resin forming the leg portion, and the synthetic resin that has flowed into the central body member is engaged with the engaging portion so that the leg portion is at the center. It is characterized by being integrally molded so as to prevent it from coming off from the main body member.

According to the method of claim 1, the end of the hollow central body member having the plug member and the bracket are arranged in the molding die, and the synthetic resin is injected into the cavity space formed inside the molding die. By molding the legs,
A roof rack having a leg portion having a high coupling strength, which can form a leg portion having a free shape without being restricted by the shape of the central body member and which prevents the synthetic resin from flowing into the central body member. Can be easily manufactured.

According to a second aspect of the present invention, the engaging portion according to the first aspect is a protrusion projecting toward the axial line side of the central body member. It is characterized by engaging with resin.

According to the second aspect of the present invention, the projection, which is the engaging portion, engages with the synthetic resin that has flowed over the projection, thereby mechanically connecting the leg portion made of the synthetic resin. The bond strength can be increased.

According to a third aspect of the present invention, the engaging portion according to the first aspect is a through hole provided in the bottom surface of the plug member, and the through hole flows through the through hole to the inside of the central body member. It is characterized in that it engages with the synthetic resin.

According to the third aspect of the present invention, the resin that has passed through the through hole and flows out to the inside of the central body portion is firmly fixed to the inner surface of the central body portion through the adhesive layer, so that the bonding strength is increased. obtain.

According to a fourth aspect of the present invention, the engaging portion according to the first aspect is a through hole provided through the wall surface of the plug member, and the outside of the central body member passes through the through hole. It is characterized in that it engages with the synthetic resin that has flowed out.

According to the method of claim 4, the leg portion formed of the synthetic resin is engaged by engaging with the synthetic resin which has passed through the through hole which is the engaging portion and has flowed out to the outside of the central body member. Can be integrally connected to the plug member and the central body member to enhance the bond strength of the legs.

According to a fifth aspect of the present invention, a synthetic resin containing a large number of fibers or particulate reinforcing materials mixed therein is injected into the cavity space according to the first to fourth aspects.

According to the method of claim 5, a large number of fiber or particulate reinforcing materials are mixed in the synthetic resin,
The strength and rigidity of the legs can be increased and the heat distortion temperature can be increased.

According to a sixth aspect, the interior of the synthetic resin is synchronized with the injection of the synthetic resin into the cavity space according to the first to fifth aspects or before the injected synthetic resin is cured. It is characterized in that an inert compressed gas is injected to expand the inside of the synthetic resin to form a space inside the synthetic resin.

According to the method of the sixth aspect, the injected synthetic resin is expanded from the inside with the inert compressed gas to prevent the sink mark from being formed on the outer side surface of the leg portion during molding. , It can improve the appearance and helps to reduce the weight of the legs.

According to a seventh aspect of the present invention, after the leg portions according to the first to sixth aspects are formed, the surfaces of the central body member and the leg portions are coated.

According to the method of claim 7, the appearance can be improved by coating the surfaces of the central body member and the leg portions.

[0022]

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

First, as shown in FIG. 2, the central body member 1
Is a hollow portion 1a having substantially the same cross-sectional shape along the longitudinal direction.
And has a rigidity that substantially bears a vertical load applied to the roof rack 18 described later.

The central body member 1 is a normal steel plate, and has a tensile strength of 50.
~ 120 kgf / mm ² high tensile strength steel plate, stainless steel plate or other steel plate or aluminum plate ERW pipe, roll forming pipe, aluminum alloy extruded pipe, etc., not limited to circular shape, but pipe shape with square or irregular cross section The material formed in (1) is selected according to the relationship between strength and design, but in the present embodiment, a pipe material formed in a substantially triangular cross-sectional shape is cut into a predetermined length and used.

The central body member 1 has a flat lower wall surface 1b facing a roof 19 side of a vehicle, which will be described later, with a gap therebetween, and a vertical wall surface 1c standing substantially vertically from the lower wall surface 1b.
Is directed inward in the vehicle width direction, and a substantially arc-shaped upper wall surface 1d connecting the vertical wall surface 1c and the lower wall surface 1b is directed outward in the vehicle width direction.

At the end of the central body member 1, a through hole 1e as an engaging portion and a vent hole 1f are formed in the lower wall surface 1b.

The vent hole 1f is provided at a position where it is not blocked by a plug member 2 which will be described later inserted into the central body member 1 or a synthetic resin 3a which is filled and constitutes the leg portion 3.

An adhesive layer 4 shown in FIG. 3 is formed on the inner surface of the end portion of the central body member 1 at a position corresponding to the side wall portion 2d of the protruding portion 2b of the plug member 2.

The adhesive layer 4 is activated by heat from the filling of the synthetic resin 3a forming the leg portion 3 to the solidification thereof and is fixed to the synthetic resin 3a by a heat activation type or the synthetic resin 3a.
A hot-melt type adhesive that is re-melted by the heat of 1 and fixed to the synthetic resin 3a is used.

The plug member 2 is formed by drawing a metal plate material with a press to form a substantially cylindrical shape with a bottom.
It has a large-sized portion 2a having an external cross-section substantially the same as the cross-sectional shape of the hollow portion 1a, and a small-sized protruding portion 2b formed in a step substantially coaxially with the large-shaped portion 2a.

The protrusion 2b has a bottom wall 2c that closes the cavity in the longitudinal direction, and the side wall 2d of the protrusion 2b faces the inner surface of the central body member 1 at a distance.

In the case of this embodiment, the plug member 2 has a plurality of elongated holes 2e as engaging portions formed on the side wall portion 2d from the large-sized portion 2a to the projecting portion 2b, and each bent portion of the side wall portion 2d. A plurality of slits 2f as engaging portions cut from the opening side of the large-sized portion 2a to near the bottom wall portion 2c of the protruding portion 2b.
And a through hole 2g as an engaging portion formed on the lower wall surface of the large portion 2a.

When the plug member 2 is inserted into the end portion of the central body member 1 and the through hole 2g is aligned with the through hole 1e of the central body member 1, the opening edge of the plug member 2 has the central body member. It is formed so as to be located inside the one edge.

Next, as shown in FIG. 3, the plug member 2 is inserted from both ends of the central body member 1 formed as described above in a state in which it is inserted by a predetermined distance G, and fixed.

In the case of this embodiment, the large-sized portion 2a of the plug member 2 is expanded to the outside through the slit 2f, and the protruding portion 2 is formed.
Inserted into the central body member 1 from b, the large member 2a
Slidably contacts the inner surface of the central body member 1 under the action of elastic deformation,
By storing and aligning the through hole 2g of the plug member 2 with the through hole 1e of the central body member 1, the opening edge of the plug member 2 is separated from the edge of the central body member 1 by a distance G. It is located inside and temporarily fixed.

In this state, the opening edge of the plug member 2 and the inner side surface of the central body member 1 are fixed by build-up welding 5.

The build-up weld 5 may be welded over the entire circumference of the opening end edge of the plug member 2 or may be welded so as to be scattered at a plurality of points along the circumferential direction, but it constitutes an engaging portion. As described above, the welding is performed so that the amount H of the build-up weld 5 protruding inward in the radial direction can be sufficiently obtained.

Then, as shown in FIG. 1, the end of the central body member 1 to which the plug member 2 is fixed and a plurality of bolts 6 as a fixture for mounting the roof rack 18 on the roof surface of the roof 19. And the core mold 7 and the cavity mold 8 of the molding mold are opened, and the core mold 7 and the cavity mold 8 are
It is arranged in the internal space 9 formed by and.

In this embodiment, the bolt 6 is the roof 1
Use a non-circular headed bolt such as a square or elliptical shape so that it will not rotate during installation on the No. 9, or if using a circular headed bolt, knurl the surface of the circular head Is preferably formed in advance.

Further, the bolt 6 has its threaded portion housed in a housing hole 7a formed in the split mold surface of the core mold 7, and the head and neck of the bolt 6 project into a cavity space 10 described later.

Subsequently, the core mold 7 and the cavity mold 8 were closed and clamped, so that the core mold 7 and the cavity mold 8 were inserted and fixed to the mold surface forming the internal space 9 and the central body member 1. With the cylindrical inner surface of the plug member 2, a cavity space 10 for molding the leg portion 3 is formed which is substantially divergent from the end of the central body 1 toward the roof 19.

Here, the cavity mold 8 has a nozzle touch 11 and a sprue 12, and the core mold 7 is a runner 13.
And a gate 14 and a gas supply passage 15.

The gate 14 is open at the bottom of the cavity 10 corresponding to the side forming the mounting surface 3b of the leg 3 on the roof 19 shown in FIG.
Is a gas injection port 15a, which is open at the bottom of the cavity space 10 between the plurality of bolts 6.

Then, the nozzle touch 1 of the cavity type 8
1 is brought into contact with a nozzle 16 of an injection molding machine, a synthetic resin 3a as a molding material for the leg 3 is injected from the nozzle 16 of the injection molding machine, and a cavity space is generated from a gate 14 via a sprue 12 and a runner 13. Inject to 10.

As the synthetic resin 3a, since the leg portion 3 to be molded is a portion which receives and supports the vertical load applied to the roof rack 18, it is assumed that the synthetic resin 3a has high strength and high rigidity. Synthetic resins such as PA, PC, PPE, etc. referred to are preferably used, and more preferably synthetic resins obtained by mixing a large number of fibers or powders or particulate reinforcing materials therein.

As the fiber of this reinforcing material, long glass fiber,
Examples include short glass fibers, carbon fibers, alumina fibers, silicon carbide fibers, and examples of powder and particulate reinforcing materials include mica and glass flakes.

Then, after the synthetic resin 3a injected into the cavity 10 flows past the gas injection port 15a, an inert compressed gas such as N ₂ gas is injected from the gas injection port 15a into the inside. And synthetic resin 3
a is continuously supplied to expand inside the synthetic resin 3a,
By forming the space 17 inside the synthetic resin 3a, the leg portion 3 is formed, and the head portion of the bolt 6 is embedded and fixed by the synthetic resin 3a forming the leg portion 3, and the plug member is formed. The synthetic resin 3a that has flowed into the inside 2 is engaged with the through holes 2g and 1e, the elongated holes 2e, the slits 2f, the build-up welding 5 and the like that form the engaging portion.

Although the synthetic resin 3a is mostly prevented from flowing into the hollow portion 1a of the central body member 1 by the bottom wall portion 2c of the plug member 2, some of the synthetic resin 3a are elongated holes 2e and slits 2.
It flows out into the gap between the projecting portion 2b of the plug member 2 and the inner side surface of the central body member 1 via f, and wraps around from the inside of the central body member 1 to the bottom wall portion 2c of the plug member 2 and solidifies. .

In the process until the synthetic resin 3a is solidified, the adhesive layer 4 and the synthetic resin 3a are fixed and firmly bonded.

The timing for injecting (injecting) the compressed gas is as follows: when the synthetic resin 3a is supplied to the cavity space 10 after occupying 70 to 90% of its volume after covering the gas injection port 15a. It is preferable to open a valve (not shown) connected to the gas supply passage 15 and start injection of compressed gas from a gas cylinder or compressor (not shown).

The gas injection port 15a has an injection nozzle 16,
It may be provided on any one of the sprue 12 and the runner 13, and may be injected in synchronization with the injection of the resin 3a.

Then, the injection of the synthetic resin 3a and the compressed gas is continued until the entire volume of the cavity space 10 is filled, and when the filling of the cavity space 10 is completed, the injection of the synthetic resin 3a is stopped. The synthetic resin 3a is cooled and solidified while maintaining the pressure of the compressed gas.

After the synthetic resin 3a is solidified, the compressed gas is discharged from the space 17 formed inside the synthetic resin 3a via the gas supply passage 15, and when the space 17 returns to the atmospheric pressure, the core The mold shown in FIG. 5 is opened by opening the mold 7 and the cavity mold 8 and releasing the molded product including the central body member 1 and the leg portion 3 which is integrally connected to the end of the central body member 1 from the roof. The rack 18 is manufactured.

Roof rack 1 manufactured in this way
Reference numeral 8 denotes a bolt protruding from the mounting surface 3b with a spacer rubber 20 made of a soft material such as rubber interposed between the vehicle outer surface of the roof 19 and the mounting surface 3b of the leg portion 3 as shown in FIGS. 6 is passed through the roof 19 from above, and a nut (not shown) is fastened to the bolt 6 from the inside of the vehicle,
The roof 19 is mounted on the outer surface of the vehicle.

According to the method of this embodiment, the end of the hollow central body member 1 having the plug member 2 and the bolt 6 are placed in the molding die, and the synthetic resin 3a is injected to mold the leg portion 3. This prevents most of the synthetic resin 3a from flowing into the hollow portion 1a of the central body member 1, but a part of the injected synthetic resin 3a passes through the elongated hole 2e and the slit 2f of the plug member 2 and is plugged. A gap between the projecting portion 2b of the member 2 and the inner side surface of the central body member 1 and the bottom wall portion 2c of the plug member 2
By wrapping around the back side of the resin and solidifying, the synthetic resin 3
Since the leg portion 3 formed by a can be strongly coupled to the plug member 2 and the central body member 1, the roof rack 18 including the leg portion 3 having high coupling strength can be easily manufactured. it can.

Further, since the build-up welding 5 is engaged with the synthetic resin 3a which has flowed over the built-up welding 5 and flowed into the inside of the plug member 2, the bonding strength of the molded leg portion 3 can be further improved.

In addition, by injecting an inert compressed gas into the injected synthetic resin 3a to form the space 17, it is possible to prevent a sink mark from being generated on the outer surface of the leg portion 3 due to molding shrinkage. You can improve the appearance.

Further, the synthetic resin 3a inside the plug member 2
Since the synthetic resin 3a on the outer side of the central body member 1 is connected through the through hole 1e of the central body member 1 and the through hole 2g of the plug member 2, it is possible to improve the retaining of the leg portion 3. it can.

Further, since the space 17 formed inside the synthetic resin 3a is stopped within the range from the end of the central body member 1 to the inside of the plug member 2, it is possible to place a load on the roof rack 18. Thus, when a vertical load is applied, the stress concentrated on the end portion of the central body member 1 can be appropriately dispersed in the leg portions 3, and the strength and rigidity can be improved.

Further, since the opening end of the plug member 2 is inserted inside the end of the central body member 1 by a predetermined distance G and the plug member 2 is fixed to the central body member 1, it is perpendicular to the roof rack 18. When a load is applied in the direction, it is possible to prevent cracks from occurring in the fixed portion between the plug member 2 and the central body member 1 due to the stress concentrated on the end portion of the central body member 1.

Further, when the roof rack 18 is attached to the roof 19, the ventilation hole 1f of the central body member 1 is located so as to face the roof 19 so that it is difficult to see, and in the hollow portion 1a of the central body member 1. When the air expands or contracts, it can flow out and flow in, and the deformation of the central body member 1 can be prevented in advance.

When the space 17 is formed in the synthetic resin 3a, only the synthetic resin 3a is injected to form the cavity space 10.
If the compressed gas is injected to form a space inside the leg portion 3 after the synthetic resin 3a is filled into the leg 3 and is hardened, the formed space 17 becomes smaller than that in the case of the above-described embodiment, The strength of the leg 3 can be further improved by compensating for the shrinkage of the resin 3a due to cooling.

Further, even if the roof rack 18 taken out from the mold is coated with a desired color tone and the coating material is cured by baking to improve weather resistance and aesthetics, the central body member 1 is Since the vent hole 1f is provided, it is possible to prevent the central body member 1 from being deformed due to an increase in internal pressure.

Further, since the resin 3a of the leg portion 3 is in close contact with the end of the central body portion 1, there is no large gap, and when coated, the whole looks like an integrated product and the aesthetic appearance is improved.

Further, in the above embodiment, the cavity space 1
Although the case where the inlet of the synthetic resin 3a to 0 and the inlet of the compressed gas are formed at different positions has been illustrated and described as an example, the inlets of the synthetic resin 3a and the compressed gas may be the same.

Further, although the bolt 6 is provided on the leg portion 3 as a mounting tool, a non-circular nut is embedded in the leg portion 3 instead of this, and the bolt is fastened to the nut from the vehicle interior side of the roof 19. The roof rack 18 can be attached to the roof 19.

Further, as shown by the phantom line in FIG. 3, if the cut-and-raised piece 2h is formed on the inside of the plug member 2, the cut-and-raised piece 2h goes over it and flows into the synthetic resin 3a.
, The coupling strength of the molded leg portion 3 can be further improved.

The cut-and-raised pieces 2h may be provided at a plurality of places.

It is also possible to improve the mounting stability of the roof rack 18 by interposing a double-sided adhesive tape or an adhesive between the leg portion 3 and the roof 19.

[0070]

As described above, according to the present invention, the following effects can be obtained.

According to the first aspect, the end of the hollow central body member having the plug member and the fitting are arranged in the molding die,
Since the synthetic resin is injected into the cavity space formed inside the molding die to mold the leg portion, the synthetic resin is prevented from flowing into the central body member, and the leg portion having high bonding strength is provided. The roof rack can be easily manufactured.

According to the second aspect, since the projection which is the engaging portion is engaged with the synthetic resin which has flowed over the protrusion, the coupling strength of the leg portion which is the synthetic resin can be increased.

According to the third aspect, the resin that has passed through the through hole and flows out to the inside of the central body portion is firmly fixed to the inner surface of the central body portion through the adhesive layer, so that the bonding strength can be increased.

According to the fourth aspect of the present invention, the leg portion made of the synthetic resin is integrated with the plug member and the central body member because the leg portion made of the synthetic resin is engaged with the synthetic resin which has passed through the through hole which is the engaging portion and has flowed out. To increase the bond strength of the legs.

According to the fifth aspect, since a large number of fibers or particulate reinforcing materials are mixed in the synthetic resin, the strength and rigidity of the legs and the heat resistance can be increased.

According to the sixth aspect, since the injected synthetic resin is expanded from the inside by the inert compressed gas, the sink mark at the time of molding is prevented from being generated on the outer surface of the leg portion, and the appearance is improved. Not only can it be improved, but it also helps to reduce the weight of the legs 3.

According to the seventh aspect, since the surfaces of the central body member and the legs are coated, the appearance can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a central body member and a plug member used in the method of the embodiment.

FIG. 3 is a cross-sectional view showing a state in which the central body member and the plug member shown in FIG. 2 are fixed to each other.

FIG. 4 is a cross-sectional view showing how the roof rack obtained by the method of the embodiment is attached to the roof.

FIG. 5 is a side view of an automobile including a roof rack obtained by the method of the embodiment.

[Explanation of symbols]

 1 Central body member 1a Hollow part 1e Through hole (engaging part) 2 Plug member 2c Bottom wall part 2d Side wall part 2e Long hole (engaging part) 2f Slit (engaging part) 2g Through hole (engaging part) 2h Cut Raised piece (engagement part) 3 Leg part 3a Synthetic resin 4 Adhesive layer 5 Overlay welding (engagement part) 6 Bolt (mounting tool) 7 Core type 8 Cavity type 10 Cavity space

Claims (7)

[Claims] 1. A method of manufacturing a roof rack mounted on a roof surface of a vehicle with legs provided at longitudinal ends of a metal-made central body member, the method being substantially along the longitudinal direction. A hollow main body having the same cross-sectional shape, a central body member cut into a predetermined length having rigidity to substantially bear the vertical load applied to the roof rack when attached to the roof, and a bottomed substantially tubular shape A plug member having a bottom wall portion that closes the cavity in the longitudinal direction and a side wall portion that faces the inner surface of the central body member, and the bottom wall portion is inserted and fixed to the inside from the end of the central body member by a predetermined distance. An engaging portion capable of engaging with a leg portion is formed on one or both of the central body member and the plug member, and at least the end of the central body member to which the plug member is fixed and the roof rack are roofed. Mount on the surface And a mounting surface for disposing a cavity mold and a core mold, which are arranged inside the injection mold composed of a cavity mold and a core mold that can be opened / closed by dividing surfaces. The leg portion is formed by injecting and filling a liquid synthetic resin into a cavity space formed by the cylindrical inner surface of the plug member inserted and fixed to the central body member, and the leg portion is formed. At least a part of the fixture is integrally fixed with resin, and the synthetic resin that has flowed inside the central body member is engaged with the engaging portion to prevent the leg portion from coming off from the central body member. A method for manufacturing a roof rack for a vehicle, which is characterized by being integrally molded. 2. The engagement portion is a protrusion protruding toward the axial side of the central body member, and engages with the synthetic resin that has flowed over the protrusion and has flowed into the back side of the protrusion. 1. The method for manufacturing a vehicle roof rack according to 1. 3. The engaging portion is a through hole provided on the bottom surface of the plug member, and engages with the synthetic resin that has passed through the through hole and flown out to the inside of the central body member. The method for manufacturing a vehicle roof rack according to claim 1. 4. The engaging portion is a through hole provided penetrating the wall surface of the plug member, and engages with the synthetic resin flowing through the through hole and flowing out to the outside of the central body member. The method for manufacturing a vehicle roof rack according to claim 1. 5. The method for manufacturing a vehicle roof rack according to claim 1, wherein a synthetic resin mixed with a large number of fibers or particulate reinforcing materials is injected into the cavity space. 6. A chemically inert compressed gas is injected into the synthetic resin in synchronization with the injection of the synthetic resin into the cavity space or before the injection-filled synthetic resin is cured. The method for manufacturing a vehicle roof rack according to claim 1, wherein the synthetic resin is expanded to form a space inside the synthetic resin. 7. The method of manufacturing a roof rack for a vehicle according to claim 1, wherein the surface of the central body member and the legs are coated after the legs are formed.