JPH08216259A - Manufacture of hollow resin molding - Google Patents

Abstract

PURPOSE: To prevent the protrusion of flash into a hollow part and to improve the connecting strength without increasing the connecting part by filling pressurized fluid in a bag internally mounted in the hollow part and having flexibility, and pressing the flash grown into the hollow part from the inside. CONSTITUTION: The sides of the ends split in fingers state of upper and lower works 11b and 11a collided with one another in a hollow state in such a manner that a bag 13 made of rubber is exhausted of nitrogen gas and contracted are inserted into the innermost part of air passages 12a to 12d. Nitrogen gas is filled in the bag 13, and regulated to a predetermined pressure. Flashes 19 generated at the connecting part tend to protrude out of flash sumps 20, 21. At this time, the bag 13 expanded by the gas is brought into pressure contact with the exterior of the one sump 20 to be the inside of a resin intake manifold 11 to close the gap of the upper end of a riser wall Jig, and hence the protrusion of the flash 19 from the sump 20 is suppressed by the brought bag 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a hollow resin molded product in which parts that have been separately molded are joined together by a vibration welding method.

[0002]

2. Description of the Related Art As one of the methods for manufacturing a hollow resin molded product, a pair of split-molded parts are vibrated with their joint surfaces pressed against each other, and the joint surfaces are welded by the friction heat generated. There is a method of integrally forming a hollow shape.

When parts are joined by this vibration welding method, a vibration welding portion that frictionally engages with each other melts to generate burrs, but in the case of forming a hollow shape, a tool is used for the burrs generated outside. However, burrs generated inside are often difficult to remove, and often remain inside. And, the burr generated inside the hollow molded product may fall off from the inner wall surface later if it protrudes into the hollow part, and various deficiencies may occur due to the burr falling off during use as a finished product. Therefore, it is necessary to reliably prevent the burr from protruding inward.

FIG. 9 and FIG. 10 show the actual construction of Sho 63-9006.
3 shows a structure of a joint portion of a conventional hollow resin-made surge tank formed by joining by a vibration welding method, which is described in Japanese Patent Publication No. The central piece 2 has a joining surface 1a and a joining surface 2a that are formed at the respective ends so that the main central piece 2 is on the lower side.
Are arranged so as to face each other. On the outside of the end of the main central piece 2 (on the left side in FIG. 10), there is a space t between the decorative wall 3 and the end where the joint surface 2a is formed, and from the joint surface 2a. It is continuously formed in the horizontal direction in a state of being raised to the upper side, and inside the end of the same main center piece 2 (right side in FIG. 10), the sub-wall 4 has a space s between the end and the end. At the same time, it is higher than the decorative wall 3 and is continuously formed in the horizontal direction, and a space t between the end portion of the main central piece 2 and the decorative wall 3 and a space s between the sub wall 4 are respectively formed. It is a space for burr pool.

[0005]

As described above, in the structure of the joint portion of the conventional hollow resin molded product by the vibration welding method, since the sub-wall 4 and the space s are formed inside the hollow portion, Therefore, there is a problem that the volume of the hollow portion is reduced.

[0006] The strength of the hollow resin molded product joined by the vibration welding method is determined by the strength of the joint having the smallest strength, and the strength of the joint is determined by the width of the welded surface. For example, FIG. 12 shows the width (joint surface width) of the vibration welding rib 5a of the hollow resin molded product 5 molded from the resin material of nylon 66 (trademark) -30% glass fiber shown in FIG. As shown in this diagram, when the width w of the vibration welding rib 5a is increased from 3 mm to 5 mm, the internal pressure fracture strength becomes 15 kgf / cm ² (1.5 × 10 ^6). N / m ² ) to 25 kg
f / cm ² (2.5 × 10 ⁶ N / m ² ), and it can be seen that the internal pressure fracture strength increases in proportion to the increase in the width w of the vibration welding rib 5.

Therefore, in order to increase the strength of the vibration welding portion, it is necessary to widen the width of the joint surface, that is, the width w of the vibration welding rib 5a. However, if the width of the joint surface is widened, the amount of burrs also increases. Therefore, it is necessary to design the space for accommodating the generated burr, that is, the burr pool 6 to be large, and as a result, the amount of protrusion of the joint portion to the outside becomes large and the hollow resin molded product 5 becomes large. There was a problem.

The present invention has been made in view of the above circumstances, and provides a method for producing a hollow resin molded product capable of preventing the protrusion of burrs into the inside of the hollow portion and improving the joint strength without enlarging the joint portion. The purpose is to do.

[0009]

As a means for solving the above problems, the present invention oscillates a pair of split-molded parts in a state where their joint surfaces are in pressure contact with each other and welds them by friction heat generated. In the method for producing a hollow resin molded product that is formed into a hollow shape by providing a burr pool adjacent to the joint surface for accommodating the generated burr, and at the time of welding, a portion inside the hollow part can be formed. By preliminarily incorporating a flexible bag body and filling the bag body with a pressurized fluid to expand the bag body, a burr generated in the burr pool and growing toward the inside of the hollow portion is pressed from the inside. Then, it is characterized in that the protrusion to the inward side is restricted.

Further, in the method for producing a hollow resin molded product, a pair of split-molded parts are vibrated in a state where their joint surfaces are in pressure contact with each other, and are welded by friction heat generated to form a hollow resin molded product. A bag body is provided adjacent to the surface for accommodating the generated burrs, and is flexible and has a burr removing means at a predetermined portion at a portion inside the hollow portion at the time of welding. Is pre-installed, the bag body is filled with a pressurized fluid to be inflated, and burrs which are generated in the burr pool and grow toward the inside of the hollow portion by the burr removing means of the inflated bag body. It is characterized by removing.

[0011]

According to the method for producing a hollow resin molded product of the present invention as set forth in claim 1, the flexible bag provided inside the hollow portion is filled with the pressurized fluid and inflated to form a joint surface. Burrs that are generated in adjacent burr pools and grow toward the inside of the hollow portion are pressed from the inside to restrict the protrusion of the inside of the hollow portion.

Further, according to the method for producing a hollow resin molded product of the second aspect of the present invention, since the burr removing means is provided at a predetermined portion of the flexible bag body provided inside the hollow portion, By filling the bag with a pressurized fluid and expanding the bag, burrs generated in the burr pool provided adjacent to the joint surface and growing toward the inside of the hollow portion are removed by the removing means.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the method for manufacturing a hollow resin molded product of the present invention is applied to a method for manufacturing a resin intake manifold will be described below with reference to FIGS.

FIGS. 1 to 5 show a first embodiment. This intake manifold 11 is provided with four cylindrical air passages 12a, 12b, 12c and 12d, and nylon 66 is made of glass fiber 30 %, The material is kneaded in advance and is preformed in a state of being divided into a lower work 11a and an upper work 11b.

On the other hand, when the upper and lower works 11b, 11a are abutted against each other and vibrated and welded, a bag body 13 to be internally provided.
Is made of rubber having elasticity such as natural rubber, isoprene rubber, butadiene rubber, styrene butadiene rubber or nitrile rubber, and is formed into a glove shape with four fingers.
Up to 5 kgf / cm ² (9.8 × 10 ⁴ N / m ^{2 up to} 4.9 × 10 ⁵
When a pressurized gas of N / m ² ) is injected, the gas expands and comes into pressure contact with the inner side surfaces of the joining portions of the upper and lower works 11b and 11a.

Further, a vibration welding jig 14 for performing vibration welding
Is provided with an upper mold 14b for fitting and holding the divided upper work 11b and a lower mold 14a for fitting and holding the lower work 11a. Both works 11a, 11b to be joined are provided in the vicinity of the lower mold 14a. A cylinder 15 filled with nitrogen gas to be injected and expanded into the bag body 13 installed inside is installed. The cylinder 15 is filled with a pressure-resistant hose 18 provided with a pressure reducing valve 16 and a shutoff valve 17. Connected to the entrance.

The upper work 11b and the lower work 11a, which are divided into upper and lower parts, are provided on the respective outer peripheral portions and four air passages 12a, 12b, 12c, which are divided into fingers.
The joint flange 11 is formed on each of the boundary portions 12d.
c and 11d are formed so as to face each other in the vertical direction. Further, a welding rib 11e having a rectangular cross section is provided on the lower surface of the joining flange 11d of the upper work 11b so as to extend in the longitudinal direction approximately at the center in the width direction of the lower surface with a rib width w ₁ (see FIG. 2) wider than the outer wall 11f of the work. There is. Further, by forming the rising walls 11g, 11g on both sides in the width direction on the upper surface of the joining flange 11c of the lower work 11a, the upper work 1
Burr pools 20 and 21 for accommodating burrs 19 generated during the welding process are formed between the side surfaces of the vibration welding rib 11e of 1b (see FIG. 2). The lower surface of the vibration welding rib 11e of the upper work 11b becomes the joining surface 11h, and the joining surface 11h is rubbed against the upper surface of the joining flange 11c of the lower work 11a, and the frictional heat generated causes the joining surface and its surroundings to melt at a melting temperature. It is designed to be heated up to welding.

Next, a case will be described in which the divided upper work 11b and the lower work 11a are integrally joined using the vibration welding jig 14 to form the resin intake manifold 11.

The upper work 11b and the lower work 11a, which have been separately molded in advance, are preheated to 50 to 150 ° C., respectively, and then mounted on the upper mold 14b and the lower mold 14a of the vibration welding jig 14. That is, a cavity is engraved in the upper mold 14b and the lower mold 14a so as to match the shapes of the works 11b and 11a, and after fitting into the cavities, the upper mold 14b and the lower mold 14a are fitted together. When they are aligned, the vibration welding ribs 11e of the upper work 11b are set so as to abut on the upper surfaces of the corresponding joining flanges 11c of the lower work.

Then, the upper work 11b and the lower work 11 are set in the upper mold 14b and the lower mold 14a and abutted against each other in a hollow shape.
With the rubber bag 13 being degassed and contracted inside a, the tip side that is split like a finger is located at the back of the air passage 12.
The tips of the pressure-resistant hose 18 of the cylinder 15 are connected to the inlets a, 12b, 12c, and 12d, respectively.

Next, the lower mold 14a of the vibration welding jig 14 is fixed, and the upper mold 14b is directed downward to approximately 20 to 40 kgf / cm.
² (2.0 to 3.9 × 10 ⁶ N / m ² ) is applied to bring the joining surface 11h of the upper work 11b into pressure contact with the upper surface of the joining flange 11c of the lower work 11a. In addition, nitrogen gas is injected into the bag 13 from the cylinder 15 so that the inside of the bag 13 has a predetermined pressure [about 1 to
5 kgf / cm ² (9.8 × 10 ⁴ N / m ^{2 to} 4.9 × 10 ⁵ N
/ M ² )] (state in Figure 2). Then, in this state, the upper mold 14b is horizontally vibrated at 200 to 300 Hz to perform vibration welding.

When the upper mold 14b vibrates, the joining surface 11h of the vibration welding rib 11e and the upper surface of the joining flange 11c rub against each other under pressure, and the friction heat generated causes the joining surface 11h and the joining flange 11c to rub. The temperature of the upper surface of. Then, when the temperature rises and the resin softens, burrs 19 are generated at the joint portion, and the generated burrs 19 are burr pool 2
At the same time, they are accumulated in 0, 21 and grow and attempt to protrude to the outside of the burr pools 20, 21 from a gap which is continuous to the lower surface of the joint flange 11d and the upper ends of the rising walls 11g, 11g in the horizontal direction.

At this time, the resin intake manifold 1
The bag body 13 inflated by nitrogen gas is pressed against the outside of the one burr pool 20 on the inner side of 1 to close the gap at the upper end of the rising wall 11g. By 13, the protrusion of the burr 19 from the burr pool 20 is pressed. As a result, the increased burrs 19 are pressed into the burr pool 20 at a high density, and are prevented from protruding toward the inside of the resin intake manifold 11.

The other burr pool 21 outside the resin intake manifold 11 is filled with a small amount of burr 19 since it has a low density because it does not close the gap, and the bottom face of the joint flange 11d and the rising wall are filled. Although it overflows to the outside of the burr pool 21 through the gap that opens between 11g and
Since it faces the outside, after the welding process is completed, the burr pool 2
It is possible to easily remove the burr 19 protruding from 1.

After the welding is completed, the nitrogen gas is removed and the bag 13 is extracted to remove the resin intake manifold 11.
Is completed. Further, the bag body 13 taken out is the next work 11
It is reused when setting a and 11b on the vibration welding jig 14.

As described above, according to the manufacturing method of this embodiment, the two divided workpieces 11a and 11b are welded together to form a hollow resin intake manifold 11.
Since the inside of the bag body 13 is expanded at a predetermined internal pressure during the production of the burrs, the burr 19 generated at the welded portion is prevented from protruding toward the inner side, so that the vibration welding rib 11e can be formed without enlarging the burr pool 20. Of the resin intake manifold 1
It is possible to prevent the turbulence of the air flow due to the protrusion inside 1 and improve the performance of the resin intake manifold 11. In addition, it is possible to prevent the occurrence of troubles such as peeling off of the internal protrusions after the resin intake manifold 11 is attached to the vehicle.

FIG. 6 shows a second embodiment of the manufacturing method of the present invention. In the first embodiment, nitrogen gas is injected into the rubber bag body 13 to keep it at a predetermined internal pressure. Thus, the burr 19 generated by the vibration welding is pressed into the burr pool 20 to prevent the burr 19 from projecting inward, whereas in this embodiment, the nitrogen gas is injected into the bag 13. And discharge are alternately repeated. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, by repeatedly inflating and contracting the bag body 13, the burr 19 is pressed into the burr pool 20 when the bag body 13 is inflated, and one point on the bag body 13 is The protruding portion of the burr 19 is removed by utilizing the fact that the bag body 13 moves in the expansion direction as the bag body 13 expands and returns to the original position when the bag body 13 contracts.

That is, when the burr 19 projects from the burr pool 20 to the inside, the burr 19 and the burr 19 projecting.
The contact point with the tip of the bag moves downward as the bag body 13 expands and returns upward as the bag body 13 contracts to move the distance S ₁
By making only the stroke, the protruding portion of the burr 19 is repeatedly bent and cut, and is removed to prevent the protruding portion to the inside. The cut burr 19
Is removed from the inside of the resin intake manifold 11 when the bag body 13 is pulled out after the welding is completed.

Therefore, according to the manufacturing method of this embodiment, substantially the same operation and effect as in the case of the first embodiment can be obtained, and the protruding burr can be broken off, so that the burr pool 20 can be made smaller. There is an advantage that you can.

FIG. 7 shows a third embodiment of the manufacturing method of the present invention. In the second embodiment, the bag body 13 is used.
By repeatedly inflating and contracting the burr 19, the projecting portion of the burr 19 is broken off to prevent the burr 19 from projecting to the inner side.
It is the same in that the nitrogen gas is alternately injected into and discharged from the bag body 23, and the bag body 23 is repeatedly inflated and deflated to make a stroke of a distance S _1. However, at a predetermined portion of the bag body 23, that is, at the time of inflation. The inner portion of the joint portion is thickly reinforced in the shape of a convex lens in cross section, and a powdery abrasive such as gold sand is fixed to the outer surface side of the reinforced portion to form an arcuate file surface 23a as deburring means. It is a thing. The same components as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, by repeatedly expanding and contracting the bag body 23, when the bag body 23 is expanded, the burr 19 is pushed into the burr pool 20 by the arcuate file surface 23a. At the same time, a point on the bag body 13 is separated by the distance S _{1 as the} bag body 23 expands and contracts.
When only the stroke is made, the arcuate file surface 23a slides on the burr 19 protruding from the burr pool 20 while being pressed, so that the protruding part of the burr 19 is scraped and removed. To prevent the protrusion.
The burr 19 that has been scraped off is the bag body 23 after the welding is completed.
Is removed from the inside of the resin intake manifold 11.

Therefore, according to the manufacturing method of this embodiment, substantially the same operation and effect as in the case of the second embodiment can be obtained.

Further, FIG. 8 shows a fourth manufacturing method of the present invention.
In the first embodiment, nitrogen gas is injected into the rubber bag body 13 and kept at a predetermined internal pressure so that the burr 19 generated by vibration welding is stored in the burr pool 20. While the protrusion of the burr 19 to the inner side is prevented by pressing it down, in this embodiment, an electric wire such as a nichrome wire is attached to a predetermined portion of the bag body 33, that is, a portion which is inside the joint portion when inflated. A heater is provided as a burr removing means. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, heat resistant rubber such as silicone rubber, acrylic rubber, fluorine rubber, ethylene / propylene rubber is used as the material of the bag body 33. Then, a predetermined portion of the bag body 33, that is, a portion inside the joint portion when inflated is thickened to have a convex lens shape in cross section to form a reinforcing portion 33a, and the outer surface side of the reinforcing portion 33a is heat-treated by heat treatment. The heat-resistant layer 34 is formed by forming the layer 34.
A nichrome wire 35 is provided at the center of the outer surface of the.

Then, nitrogen gas is injected into the bag body 33 to inflate it to a predetermined internal pressure, and vibration welding is performed while the bag body 33 is pressed against the inside of the joint portion and the nichrome wire 3 is used.
5 is energized to generate heat.

Therefore, when the burr 19 generated in the burr pool 20 is to be projected from the burr pool 20,
While being pressed into the burr pool 20 by being pressed by the outer surface of the reinforcing portion 33a of the bag body 33 having an arcuate cross-section, it is heated by the high-temperature nichrome wire 35 and melted to form a high-density burr 19 in the burr pool 20. Accumulated.

Therefore, according to the manufacturing method of this embodiment, substantially the same operation and effect as in the case of the first embodiment can be obtained, and the generated burrs 19 can be accumulated in the burr pool 20 at a high density. The burr pool 20 can be made smaller. In addition, if the burr 19 is burr pool 2
Even if it protrudes from 0 to the inside, the protruding portion of the burr 19 is heated and melted, firmly adheres to the inner surface of the resin intake manifold 11 and solidifies, and the surface is formed smoothly, so that it is mounted on the vehicle. There is no risk of peeling and falling off later, and there is no cause of disturbing the air flow.

In this embodiment, the nichrome wire 35 is used as a means for melting the burr 19 protruding inward of the hollow portion.
However, it is also possible to dissolve and remove the burr 19 with a solution in which only the burr 19 dissolves.

In each of the above embodiments, the case where high-pressure nitrogen gas is used as the pressurized fluid has been described, but other gases such as compressed air and liquids such as water and oil are used in almost the same manner. Can be carried out.

[0041]

According to the first aspect of the present invention, the flexible bag provided inside the hollow portion is provided adjacent to the joint surface by filling and expanding the pressurized fluid. By pressing the burr generated in the burr pool and growing toward the inside of the hollow portion from the inside, the protrusion to the inside of the hollow portion is surely regulated.

According to the second aspect of the present invention, since the burr removing means is provided at a predetermined portion of the flexible bag body provided inside the hollow portion, the pressurized fluid is supplied to the bag body. By filling and expanding, the burr removing means acts on the burr to remove it, and prevents the burr from projecting inward of the hollow portion.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view taken along line I-I of FIG. 3 showing a state in which a rubber bag body in the first embodiment of the present invention prevents a burr from protruding toward the inside.

FIG. 2 is an explanatory view showing a state in which a rubber bag is also set inside a work.

FIG. 3 is a sectional view taken along line III-III in FIG. 4 showing the resin intake manifold that has completed welding.

FIG. 4 is a sectional view taken along line IV-IV of FIG.

FIG. 5 is a side view of a vibration welding jig used in the manufacturing method of this embodiment.

FIG. 6 is a view corresponding to FIG. 1 showing a state in which burrs are broken off by a rubber bag according to a second embodiment of the present invention.

FIG. 7 is a view corresponding to FIG. 1 showing a state in which burrs are scraped off by a rubber bag body according to a third embodiment of the present invention.

FIG. 8 is a view corresponding to FIG. 1 showing a state in which burrs are melted by a heating means in a fourth embodiment of the present invention.

FIG. 9 is an explanatory view showing a structure of a joint portion in a conventional manufacturing method by vibration welding.

FIG. 10 is likewise an explanatory view showing a state of a joint portion when vibration welding is completed.

FIG. 11 is a sectional side view showing a general structure of a joint portion in a conventional manufacturing method by vibration welding.

FIG. 12 is a diagram showing the relationship between the width of a vibration welding rib that serves as a joint and the internal pressure fracture strength.

[Explanation of symbols]

 11 Resin Intake Manifold 11a Lower Work 11b Upper Work 11c Joining Flange 11e Vibration Welding Rib 12a Air Passage 13 Rubber Bag 14 Vibration Welding Jig 14a Lower Die 14b Upper Die 15 Cylinder 19 Burr 20 Burr 23 Bag 23a File Face 33 bag 33a reinforcing part 34 heat-resistant layer 35 nichrome wire

Claims (2)

[Claims] 1. A method for producing a hollow resin molded product, wherein a pair of split-molded parts are vibrated in a state where their joint surfaces are in pressure contact with each other and welded by friction heat generated to form a hollow resin molded article. A burr pool for accommodating the generated burr is provided adjacent to the surface, and a flexible bag body is preliminarily provided inside the hollow portion when welding and the pressurized fluid is applied to the bag body. By filling and expanding
A method for producing a hollow resin molded product, characterized in that a burr that is generated in the burr pool and grows toward the inside of the hollow portion is pressed from the inside to restrict the protrusion toward the inside. 2. A method for producing a hollow resin molded product, wherein a pair of split-molded parts are vibrated in a state where their joint surfaces are in pressure contact with each other and are welded by friction heat generated to form a hollow resin molded article. A bag body is provided adjacent to the surface for accommodating the generated burrs, and is flexible and has a burr removing means at a predetermined portion at a portion inside the hollow portion at the time of welding. Is pre-installed, the bag body is filled with a pressurized fluid to be inflated, and burrs which are generated in the burr pool and grow toward the inside of the hollow portion by the burr removing means of the inflated bag body. A method for producing a hollow resin molded product, which comprises removing the hollow resin molded product.