JPH01242217A - Manufacture of resin manifold - Google Patents

Abstract

PURPOSE:To manufacture a manifold of various kinds of shapes with superior mechanical strength easily by combining a core having superior flexibility and shape retaining properties and a metal core. CONSTITUTION:A core 1 is heated with a flexible heater 5 and a low melting point alloy 6 sealed inside is melted to deform into a desired shape. After deforming, the low melting point alloy 6 is solidified by cooling and fixing into a desired shape. A core 7 for molding is formed by combining the core 1 of desired shape and a metal insert block 9. Said core 7 is inserted into a model mold 8 of a manifold, and then resin 10 is injected to coat the outer peripheral section of the core 7 for molding. Then, a molded product is released from the model mold 8, and a flexible heater 5 of the core 1 is heated to melt the low melting point alloy 6 and pulled out, and then the metal insert block 9 is pulled out. Pulling completed in several minutes and a desired manifold is manufactured.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a resin manifold (for example, a resin intake pipe for an automobile) that is composed of a plurality of bent pipe parts and a hollow expanding part connected to the bent pipe parts. ).

(Prior art) To explain the conventional technology using the example of an automobile intake pipe as a representative example, most automobile intake pipes are currently made by casting from metal materials such as aluminum alloys due to their complex hollow shapes. ing. However, the inner wall of the intake pipe made with the above method and material is rough (because of this, it has the disadvantages of large pressure loss, low intake efficiency, and heavy weight, compared to the inflow of air into the engine combustion chamber). have.

The technology related to the present invention includes low melting point alloys (for example, 1
A core of a desired shape is made from bismuth alloy (38°C), the core is inserted into a mold, the core is coated with resin, and the core is eluted to create a resin intake pipe. There is a manufacturing method. The inner wall surface of the intake pipe made by this method is smooth, which greatly contributes to improving engine performance.

(Problems to be Solved by the Invention) However, an intake pipe made using a core of a low melting point alloy requires heating (heat transfer) using hot air or a heater to elute the core. That is, since the elution of the core is rate-determined by the state change of thermal melting of the low melting point alloy, it takes time to elute and remove the core, and the production time per intake pipe becomes longer. Furthermore, if the heating temperature of the core is increased in order to shorten the elution time of the core, the product material will be subject to undesirable thermal effects, and the materials that can be used will be limited. In addition, in the case of an intake pipe with a complicated internal shape, it is difficult to completely remove the low melting point alloy that has adhered to the inner wall of the intake pipe during core elution, and the fixed low melting point alloy may remain on the inner wall of the intake pipe. If it is attached to the engine as it is, there is a high possibility that it will fall off due to vibration etc. and be taken into the engine, causing serious trouble.
At present, there are still many problems in putting it into practical use.

(Means for Solving the Problems) The present invention provides: (1) A core l having a plurality of bending properties and shape retention properties to form a bent pipe part, and a hollow expanding part connected to the core bending pipe part. Metal insert 9 to be formed
After connecting them, the plurality of cores 1 to form the bent pipe portion are deformed into a desired shape to form a molding core 7.
After inserting this into a mold 8 and coating it with resin 10 to obtain a molded product, the molded product is made into a plurality of molding cores that have both flexibility and shape retention. A plurality of bends characterized by pulling out the insert 1 and the metal insert 9, and, if necessary, using a resin component 11 to cover the opening of the hollow expanding part from which the metal insert 9 was pulled out by welding. Method for manufacturing a resin manifold consisting of a pipe portion and a hollow expanding portion connected to the bent pipe (2) A plurality of cores having flexibility and shape retention for forming a bent pipe portion After connecting the plurality of cores using the branch part 14, a metal insert 16 is formed to form a hollow expanding part that connects the plurality of cores to the bent pipe part.
The molding core 13 described in item (1) above, characterized in that the molding core 13 obtained by connecting the molding core 13 to Method for manufacturing a resin manifold in which the pipe portion is at least partially branched (3) The resin 10 is obtained by foam molding.
tl or the method for manufacturing a resin manifold described in section (2) (4
) Provides a method for manufacturing a resin manifold according to item (11, (21) or (3) above, wherein the manifold is an intake pipe.

For example, in the case of automobiles, the hollow extending section refers to the surge tank section of the intake pipe or the carburetor mounting section, and the bent pipe section refers to the hollow extending section that directs air or air-fuel mixture to the engine combustion chamber. It refers to a passage that leads.

The present invention provides a method for easily manufacturing a resin manifold, such as a resin intake pipe, by using a core and a metal insert that have both flexibility and shape retention.

The present invention can be widely applied to a method of manufacturing a manifold made of resin and having the configuration described in items (1) to 4) above.

DETAILED DESCRIPTION OF THE INVENTION In order to provide a convenient explanation of the present invention, an example of an automobile intake pipe will be described below.

However, the technical scope of the present invention is not limited to these examples.

For example, when the present invention is intended to manufacture a resin intake pipe for an automobile, the following steps are followed. Below, Section 1.2.3.4
, 5.6, the present invention will be explained.

In. A plurality of core materials (for example, metal flexible pipes) 2 having both bendability and shape retention properties, which are to form the bent pipe portion of the intake pipe, are non-adhesive to the resin 10 and are A core 1 is coated with a heat-resistant elastomer 3 that does not flow at the molding temperature of the resin so as to eliminate surface irregularities, and a metal insert is formed to form a hollow widening part having an opening connected to the bent pipe part. Connect child 9,
This is referred to as a molding core 7.

The above-mentioned bendability is caused by the bending and unbending force of the core 1 that occurs when the core 1 is pulled out from the molded product (intake pipe), and between the core surface and the coated resin 10.・It means that the core 1 can be deformed into a protrusion with a force that does not exceed the breaking strength of the base material of the molded product when the pull-out force caused by the vibration force of the core 1 is generated. In addition, shape retention refers to maintaining a desired shape in a mold and having at least enough rigidity not to be deformed by resin flow pressure during molding.

As the core material 2 (embodiment) having both flexibility and shape retention, a flexible tube or hose having flexibility is made of a low melting point alloy 6 (for example, a melting point of 124°C, a combination of bismuth and lead). There is one in which the low melting point alloy 6 is encapsulated with a crystalline alloy and heated to melt the low melting point alloy 6 to provide flexibility, and the low melting point alloy 6 is solidified by cooling to provide shape retention. The shape retention of the core 1 should be such that it has at least enough rigidity to not be deformed by the flow pressure of the resin 10 covering it, but if necessary, the amount of low melting point alloy 6 and the shape of the encapsulation (for example, a round bar shape) may be determined. , hollow pipe shape), the rigidity can be freely increased or decreased. However, the structure of the core material 2 and the material forming the structure are not particularly limited.

As the elastomer 3 covering the core material, natural rubber such as polyisoprene, synthetic rubber such as silicone rubber, fluoro rubber, urethane rubber, butadiene rubber, thermoplastic elastomer, etc. can be used. The material is not particularly limited as long as it has the functions of being heat resistant and non-adhesive to the resin 1O and disappearing at the molding temperature of the resin IO to be molded.

FIG. 1 shows an example of the core 1, in which 18 is a support for the flexible heater 5, 19 is a support for the metal flexible tube 2, and 20 is a power source.

) Next, the core l forming the bent pipe part of the molding core 7 is heated, the low melting point alloy 6 sealed inside is melted and deformed into a desired shape, and then cooled as it is, for example, released. A shape is produced by solidifying the cold) low melting point alloy 6. External heating (for example, hot air) may be used as a heating method for the core l that forms the bent pipe portion, but a bendable heater 5 is inserted inside the core to shorten the operation time for shape creation. However, direct heating from the inside is more effective.

Further, the shape of the core 1 may be formed either after or after the core 1 is connected to the metal insert 9.

c) The molding core 7 deformed into the desired shape is inserted 5 into the residual dust 8, and the outer periphery of the core is coated with resin lO. Methods for molding the resin (molded product) 10 onto the surface of the molding core 7 include injection molding or foam injection molding when using a thermoplastic resin, and cast molding when using a thermosetting resin. , transfer molding, compression molding, etc. At this time, the resin used may be any known resin, but it is selected in consideration of the performance as an intake pipe.

Furthermore, foam molding is particularly effective as a molding method for the resin (molded article) 10. Foam molding refers to a molding method in which only resin flow pressure and foaming pressure are applied to the core l during molding, and no force such as injection pressure during injection molding is applied, for example. Therefore, the compressive force of the resin on the core 1 is small, and the pulling force required to pull out the core 1 from the molded product can be reduced. However, the resin used and the molding method are not particularly limited. Furthermore, it goes without saying that the resin may contain reinforcing materials, fillers, foaming agents, colorants, stabilizers, lubricants, etc., depending on the intended use of the product.

2) After molding, the core l constituting the molding core 7 is heated externally by hot air or the like or internally heated by the heater 5 inserted into the core to form a low melting point alloy 6 sealed inside the core. The molded product 12 is pulled out by melting and bending, and then the metal insert 9 is pulled out from the opening of the hollow expanding portion.

e) In the molded product 12, if the opening of the hollow expanding part from which the metal insert 9 is pulled out is too large or unnecessary, if necessary, [by welding and sealing with the resin part 11, get. At this time, it is of course preferable that the material used for the resin part 11 be the same as that of the molded product. Further, this opening may be used to fix attached parts (for example, parts having an air 70 meter, pressure sensor, etc.) by bolting, adhesion, welding, or the like.

The welding method may be a known method such as spin welding or ultrasonic welding.

f) If the bent pipe that makes up the intake pipe is partially branched, it must be integrally molded or at least two
A plurality of cores l are connected by a branch part 14, which is formed by fitting, gluing, welding, etc., the parts that have been molded separately, and then connecting these a number of parts to a metal insert that forms a hollow expanding part. 16 to form a molding core 13. The branch part 14 only needs to have the function of connecting a plurality of cores 1 by inserting them, inserting them, etc., and the branch part 7
The structure and material are not limited. For example, resin, metal, ceramic, etc. can be used as the material.

(Examples and Comparative Examples) Comparative Example 1 A core of a low melting point alloy (melting point 124°C) was produced using model type 8 of an intake pipe, which is composed of a bent pipe part and a hollow widening part connected to the pipe part. After inserting it into the mold, the injection pressure was 500 passages/cm' and G F was 33%.
A reinforcing nylon 66 resin was injection molded to form a 4m-thick hole on the outer periphery of the core. Next, the molded product was taken out from the mold and placed in a gear oven at 150° C. to dissolve the core. Elution of the core took more than 30 minutes, and the molded article showed discoloration and was undesirably strongly affected by heat.

Example 1 A metal flexible tube (outer diameter φ19 g, inner diameter φ1611) was used as the core material 2, and heat-resistant Nistomer 3 (silicon rubber, wall thickness 4 mm) was coated on this to eliminate irregularities on the surface of the core material 2. did. Next, a flexible heater 5 (heater capacity t 60 W/m, outer diameter φ6) is inserted into the core material 2, and a low melting point alloy 6 (melting point 124°C) is melted between the core material 2 and the flexible heater 5. It was poured into core 1.

Next, the plurality of cores 1 are inserted into a metal insert 9 forming a hollow expanding part, the core 1 is heated by a flexible heater 5, the low melting point alloy 6 is melted, and after being deformed into a desired shape, it is cooled as it is. It was solidified to form a molding core 7. After inserting this into the intake pipe model fMs, the injection pressure was 500 k.
The outer periphery of the molding core 7 was coated with a thickness of 4 mm by injection molding with GF33% reinforced nylon 66 resin at a strength of was heated to melt the low melting point alloy 6 and then pulled out, and then the metal insert 9 was pulled out.The operation of pulling out the core 1 and the metal insert 9 was completed within a few minutes, and the core The pulling force of l was as low as about 30 hours.Finally, the opening of the hollow widening part from which the metal insert 9 was pulled out was covered by spin welding with the resin part 11, and the intake pipe model molded product was easily formed. was gotten.

Example 2 After inserting the same molding core 7 as Example 1 into the mold 8, Q)
' 33% reinforced nylon 66t# resin was coated on the outer periphery of the molding core 7 to a thickness of 4 mm by low foaming injection molding (cell ratio 5 to 10%) using short shot removal. Next, the molded product was removed from the mold, and the core 1 was removed in the same manner as in Example 1.
and the metal insert 9 was pulled out. Core 1 and metal insert 9
is 10 to 3 compared to the general injection molded product shown in Example 1.
It came off extremely easily with 0% less force.

Example 3 A model type 15 of an intake pipe is constructed of a plurality of bent pipe parts and a hollow widening part connected to the pipe parts, and the bent pipe parts are at least partially branched. A molding core 13 having the above-mentioned molding core 13 was inserted, and the outer periphery of the molding core 13 was coated with a wall thickness of 4 mm by injection molding with 33% GF reinforced nylon 66 resin at an injection pressure of 500 #/cwt2. The molding core 13 is made by dividing the same core 1 as in Example 1 into two parts in advance using 33% GF reinforced nylon 66 resin and connecting them with a branch part 14 having a snap-fitting structure formed by injection molding. A plurality of these are connected to a metal insert 16. After molding, the molded product 17 was also removed from the mold 15, and the core 1 and metal insert 16 were pulled out in the same manner as in Example 1. By using the branch part 14, a molded product with a small number of bent pipe parts (both partially branched) was easily obtained.

(Effect of the invention) The present invention exhibits the following unique effects.

(1) By using a core with multiple flexibility and shape retention properties, metal inserts, and branch parts, manifold pipes of various shapes with excellent mechanical strength, such as intake pipes, can be easily manufactured. can be manufactured.

(a) The core 1 and the metallic insert can be used repeatedly, and do not require the manufacturing process and operations such as elution and removal that are found in cores made of low-melting point alloys, and therefore do not require any major additions. No equipment is required.

(31 Molded products made by foam injection molding have less compressive force on the molding core than molded products made by injection molding, so it is easier to pull out the core 1 and the metal insert. do.

(4) If the current metal intake pipe is made of resin according to the present invention, it will be possible to reduce the weight of the intake pipe, and
Figures 3, 4, and 5.6 show examples of the invention. FIG. 1 shows a schematic diagram of a core 1 having both flexibility and shape retention properties used in this example, and FIG. 2 shows a molding core 7 and a metal core used in Example 1. A schematic diagram of mold 8 is shown, FIG. 3 is a schematic diagram of a model molded product of the resin intake pipe obtained in Example 1.2, and FIG. 4 is a schematic diagram of the molding core 1 used in Example 2.
3 and a mold 15, FIG. 5 shows a schematic diagram of a model molded product of a resin intake pipe obtained in Example 3, and FIG. 6 shows a branch part 14 having a snap fit structure. A schematic diagram is shown.

1: Core 2: Core material (e.g. metal flexible tube) 3: Heat-resistant elastomer (e.g. silicone rubber) 4: Support part within the whole mold 5: Flexible heater 6: Low melting point alloy 7: Molding core ( Examples 1, 2) 8: Gold (Examples 1, 2) 9: Metal insert (Examples 1, 2) lO: Resin (Examples 1, 2.3) 11: Resin parts (Example 1) , 2) 12: Molded product (Example 3) 13: Molding core (Example 3) 14 Bifurcated part (Example 3) 15: Mold (Example 3) 16: Metal insert (Example 3) 3) 17: Molded product (Example 3) Patent applicant Asahi Kasei Industries, Ltd. Figure 1 Figure 2 Figure 3 Figure 1 Figure 4 Figure 5

Claims (1)

[Claims] After connecting a plurality of cores 1 having both bendability and shape retention properties to form a bent pipe part and a metal insert 9 to form a hollow expanding part connected to the bent pipe part, A plurality of cores 1 to form a bent pipe part
is deformed into a desired shape and inserted into a mold 8 as a molding core 7 and coated with resin 10 to obtain a molded product, and then the molding core is constructed from the molded product. It has a plurality of bent pipe parts and a hollow expanding part connected to the bent pipes, which is characterized by pulling out the core 1 and the metal insert 9, which have both flexibility and shape retention. Manufacturing method for resin manifold consisting of