JP4486900B2 - Synthetic resin casing for vehicle and method for manufacturing the same - Google Patents

Description

  The present invention relates to an air cleaner casing for covering an element of an air cleaner connected to an engine of an automobile or a motorcycle.

  In general, air cleaner elements connected to automobile and motorcycle engines are structures with low mechanical strength, such as filter paper and filter nets, so the outer surface is made of a highly rigid casing made by injection molding synthetic resin. It covers and protects. On the other hand, the housing made of synthetic resin is damaged due to dust that is rolled up from the road surface during traveling due to static electricity generated by friction with air sucked into the engine or air that contacts the vehicle while traveling. was there.

  Since the dust attached in this way may be inhaled into the engine, in order to eliminate such inconvenience, a conductive resin such as ABS resin is used as a synthetic resin material, and the body frame is used. It is preferable that the charge is erased by contact.

  However, in recent years, in order to reduce the fuel consumption of vehicles, there is no social environment where only a change in material is required in order to further reduce weight and cost, so we considered saving fossil resources. Therefore, in consideration of the fact that the casing is molded by injection molding, the inventors try to impart conductivity by mixing carbon in a pellet-shaped synthetic resin material put into an injection molding machine. did.

  However, it has been found that in order to impart conductivity by adding carbon, an amount of carbon exceeding 50% by weight is required. In addition, it was expected that it would be quite difficult to mix commercially available fine carbon particles in a melted synthetic resin having a high viscosity. Furthermore, since a large amount of carbon particles is mixed in the synthetic resin as a base material, a decrease in the mechanical strength of the synthetic resin material itself remains as an anxious material.

Therefore, bamboo fiber, which is conventionally known as a lightweight reinforcing material for synthetic resins
, In view of the above, the semi-dried bamboo was pulverized with a mill, the powdered powder was removed and carbonized in a furnace to make mixing easy. When the bamboo material is crushed, about half of the bamboo is powdered and the rest is needle-shaped with a diameter of about 10 to 200 μm and a length of about 1 to 2 mm, and various thicknesses. It was observed to be dispersed in a scale-like shape having a size of 0.1 to 0.3 mm and a size of about 1 to 3 mm.

However, if half of the powder was pulverized, there was a risk of producing a huge amount of waste during production. In addition, even needle-shaped or thin pieces are expected to collapse into powder during the heating and carbonization process, and even when melted, there is considerable mixing with synthetic resins with relatively high viscosity. Difficulties were expected.
JP 7-285105 A Nikkan Kogyo Shimbun "Advanced Technology" column dated July 9, 2004

  One of the issues is to suppress the generation of static electricity due to friction between the surface of the housing and the air by mixing a large amount of conductive material that is inexpensive and can be incinerated into the plastic. There is. Further, by making the conductive material a carbonized bamboo material, it is possible to obtain a housing that minimizes a decrease in mechanical strength despite the large amount of carbides mixed using the elasticity of the bamboo material. .

  Two of the problems are that the material of the casing used by the injection molding method is homogeneously mixed with a synthetic resin as a base material and a large amount of bamboo materials ranging from 55 to 65% by weight with respect to the synthetic resin, and In the process of manufacturing pellets and molding the casing, the mixed bamboo material is appropriately carbonized using heat applied to melt the synthetic resin.

  The housing according to the present invention is obtained by carbonizing bamboo material and powdery material composed of relatively small powdery particles obtained by carbonizing bamboo material in a synthetic resin base material to be injection molded. In addition, it includes a needle-shaped material made of relatively large and slender particles, and the needle-shaped material is characterized in that a core portion that has not been carbonized remains in the center. Further, the manufacturing method according to the present invention is a material for manufacturing bamboo pellets by crushing bamboo as a raw material, mixing with a synthetic resin as a base material, and then heating to carbonize the bamboo material in a state where the synthetic resin is melted. The most important feature is that it includes a process and a molding process in which the pellets obtained in the previous process are melted and heated and injected into the inside of a heated molding die, and carbonization of the bamboo material proceeds. .

  According to the synthetic resin casing for a vehicle according to the present invention, although the synthetic resin is injected and molded, a large amount of carbon mixed in the casing generates conductivity, and static electricity is generated. Generation | occurrence | production is suppressed, and adhesion of the dust which jumps in and out of a housing | casing is suppressed. Moreover, although a housing | casing exhibits black because of the mixed carbon, since carbon is chemically stable, there is no inferiority. In addition, the synthetic resin that forms the housing can be easily incinerated unlike flame retardant fibers such as glass fibers and carbon fibers.

  According to the method for manufacturing a casing made of a synthetic resin for a vehicle according to the present invention, a large amount of carbon can be uniformly distributed in a synthetic resin as a base material, and excellent conductivity can be obtained. In addition, needle-like materials containing bamboo fibers that have not been carbonized leave a high bending strength, so even if a large amount of carbon is mixed in the base material, the decrease in mechanical strength can be minimized. There are effects such as being able to.

  The purpose of adding electrical conductivity to a synthetic resin casing produced by injection molding by adding a large amount of carbide was achieved without sacrificing productivity and mechanical strength.

  FIG. 1 shows a synthetic resin air cleaner case 10 for a motorcycle, which is an embodiment of a synthetic resin casing for a vehicle according to the present invention, and an engine that does not show a casing represented by the air cleaner case 10. The connecting pipe 20 for connecting to is shown. FIG. 2 is a cross-sectional view illustrating the internal structure of the air cleaner case 10. Inside the air cleaner case 10, a support frame 23 that supports the air cleaner element 22 is detachably attached to the stopper cylinder 26 by bolts 24. The other end of the stopper cylinder 26 protrudes to the outer surface of the air cleaner case 10 and the upstream end of the connecting pipe 20 is fitted to the outer surface. Reference numeral 28 denotes a fastening band for fastening the connecting pipe 20 to the outer surface of the support frame 23. The above configuration is not much different from that conventionally used.

  FIG. 3 is a cross-sectional view corresponding to FIG. As is apparent from this figure, the air cleaner case 10 is composed of a main box 12 having an upper surface opened and a lid 14 for closing the upper surface opening. Reference numeral 18 denotes a vent hole through which the retaining cylinder 26 is inserted.

  FIG. 4 is a plan view showing the main part of FIG. Reference numeral 15 denotes a clip for holding the main box 12 and the lid 14 in an openable closed state. The clip 15 is made by bending a plate-like spring material. Reference numeral 16 denotes a bracket for bolting the main box 12 to a vehicle frame (not shown), and also has a function of grounding the conductive air cleaner case 10 to the vehicle frame. Reference numeral 17 denotes a suction pipe formed integrally with the lid body 14 for communicating the inside of the air cleaner case 10 to the atmosphere.

  In addition to the main box 12 and the lid 14 constituting the air cleaner case 10 as the casing, the support frame 23 made of synthetic resin and the members made of synthetic resin such as a stopper tube are 50% by weight relative to the base material polypropylene. More than carbon is mixed. For this reason, the air cleaner case 10 is conductive and has a black appearance due to carbon.

  As is clear from the cross-sectional view shown in FIG. 5, the carbon mixed in the base material is a powder composed of relatively small powder particles that are obtained by crushed bamboo and occupy approximately half of the total amount. Although the material 30 is included and this produces conductivity, the decrease in the strength of the synthetic resin due to the inclusion of this large amount of carbon is compensated by the thin and long needle-like material 32.

  When the needle-shaped material 32 is cross-sectioned, as shown in FIG. 6, it can be seen that it is composed of a carbonized skin portion 36 and a core portion 38 that is located in the center of the needle-shaped material 32 and remains bamboo fiber as it is. . The needle-like material 32 is a fibrous portion of bamboo material generated in the crushing stage, and a strong bending strength remains in the uncarbonized core portion 38. Therefore, the synthetic resin as a base material, in this example, polypropylene, is reinforced by bamboo fibers forming the core portion 38, and the decrease in mechanical strength due to the large amount of carbon mixed therein is compensated.

  Next, a method for manufacturing a housing represented by the air cleaner case 10 will be described. The housing 10 is manufactured by injection molding as in the conventional case. As a material used in this injection process, bamboo material of 55 to 65% by weight is mixed in polypropylene as a base material.

  The bamboo material is first crushed and crushed by a mill in the crushing process, and as shown in FIG. 7, the powdery material 30 in an amount exceeding 50%, the scale portion 34 exceeding 20%, and The needle-like material 32 is formed in the shape of a needle that forms the remainder.

  The crushed bamboo is mixed with a synthetic resin, in this example, polypropylene, in the above-described ratio before being formed into pellets, and heated to 220-230 ° C. by heating means attached to the extruder. In this heating process, the polypropylene melts and enters into the gaps between the crushed bamboo materials to fill the space. That is, bamboo fiber is embedded in polypropylene. Thus, the difficulty of mixing and stirring carbon into the melted synthetic resin is eliminated, and a large amount of bamboo as described above can be mixed.

  Bamboo material heated to a high temperature exceeding 200 ° C. in the extruder begins to carbonize and progresses, but before the carbonization is finished, it is extruded into a rope shape by an extruder, cut into a predetermined length, and formed into pellets. The material process ends.

  The pellets thus obtained are heated again by an injection molding machine in the next molding step. And it inject | pours into a shaping die heated in the state which the synthetic resin fuse | melted by high pressure, and the cavity formed in the inner surface of a shaping die is filled. Of the bamboo material mixed in the synthetic resin, the remaining part excluding the needle-like material 32 mainly composed of bamboo fiber becomes finer in the process of being pressurized and flowing in the extruder or the injection molding machine. This is the basis for the homogeneous distribution of carbon in the interior.

  In this manner, the powder material 30 of the bamboo material is entirely made up by appropriately setting the size of the bamboo material, especially the needle-shaped material 32, and the heating time including the molding of the pellet and the molding of the housing. The needle 32 is carbonized with the core 36 remaining. Thus, since the crushed bamboo material is carbonized by heating for forming the pellet and the casing, it is possible to omit special means for carbonization.

1 is a front view of an air cleaner case for a motorcycle showing one embodiment of the present invention. FIG. 3 shows the inside of FIG. 1 and is a cross-sectional view corresponding to the II-II cross section in FIG. 4. FIG. 3 is an exploded view showing a main part of FIG. 2. It is a top view which shows the principal part of FIG. It is an expanded sectional view which expands and shows the arrow III part in FIG. It is an expanded sectional view which expands and shows the cross section of the acicular material in FIG. It is a distribution map which shows the particle size of the crushed bamboo material.

Explanation of symbols

10 Air cleaner case (housing)
12 Main Box 14 Lid 15 Clip 16 Bracket 17 Suction Pipe 18 Vent Hole 20 Connection Pipe 22 Air Cleaner Element 23 Support Frame 24 Bolt 26 Fastening Tube 28 Fastening Band 30 Powdery Material 32 Needle Material 34 Scale Part 36 Skin Part 38 Core Part

Claims (3)

  In the base material of injection-molded synthetic resin, it consists of powdery material consisting of relatively small powdered particles obtained by carbonizing bamboo material, and relatively large elongated particles obtained by carbonizing bamboo material. A synthetic resin casing for a vehicle that includes a needle-like material, and the needle-like material has a core portion that has not yet been carbonized at the center.   Bamboo material is pulverized, mixed with the synthetic resin used as the base material, and then heated to carbonize the bamboo material with the synthetic resin melted. A method of manufacturing a synthetic resin casing for a vehicle, comprising: a molding step in which pressure is injected into a molded mold heated and melted to allow carbonization of bamboo material to proceed. The method for producing a synthetic resin casing for a vehicle according to claim 2, comprising bamboo material in an amount exceeding 50% by weight with respect to the synthetic resin.

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