JPH05155374A - Light vehicle frame made of natural fibers reinforced composite tube - Google Patents

Abstract

PURPOSE:To enable a light vehicle frame made of natural fiber reinforced composite tubes to be lightened, and also enable shock resistance to be enhanced. CONSTITUTION:Composite material composed of matrix such as thermalhardening plastics and the like, and of material in a paper series made from natural, fibers, is molded hardened into a pipe shape. In this case, the composite material is wound around a core member so as to be molded and hardened into a pipe shape. And a frame is then built up with the aforesaid pipes 3 joined with joints made of metal, reinforced plastics and the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frame for a light vehicle, such as a bicycle frame, made of a natural fiber reinforced composite pipe.

[0002]

2. Description of the Related Art Pipes made of fiber-reinforced composite material mainly composed of chemical fibers such as carbon fibers are widely used as frames for light vehicles instead of pipes made of metal (for example, iron or aluminum). A metal frame for a light vehicle is made by a method such as welding or brazing a metal pipe and a joint or joining with an adhesive.

A frame made of a carbon fiber pipe for a light vehicle is made of a composite material in which carbon fiber and a synthetic resin are composited into a pipe shape to produce a carbon fiber reinforced composite pipe, which is made of metal and reinforced plastic. It is created by joining the joint and the joint with an adhesive.

[0004]

The conventional frame for a light vehicle using the metal pipe is heavy and difficult to operate when it is powered by human power, and is inferior in acceleration performance and climbing ability. There are problems such as. Further, even when a light power source such as a battery is provided, there is a problem that power is consumed in a short time.

A frame for a light vehicle made of a fiber-reinforced composite material mainly composed of a chemical fiber such as carbon fiber has no chemical reaction at the bonding interface between the chemical fiber and the synthetic resin, and is bonded by a physical anchor effect. Is being done,
There is no clear theory regarding chemical bonding. Also, since the elongation of the chemical fiber itself is very small, delamination occurs at the adhesive interface between the carbon fiber and the synthetic resin during impact,
There are problems such as brittleness of impact resistance and brittle fracture of synthetic resin,
It lacks safety with respect to shock resistance during driving.

Further, since carbon fiber is a hard material,
Vibration from the road surface is directly transmitted to the human body, which is a problem in terms of ride comfort. The present invention has been made in view of the above problems, and an object of the present invention is to provide a lightweight vehicle frame made of a natural fiber reinforced composite pipe, which is lightweight and can improve impact resistance.

[0007]

In order to achieve the above-mentioned object, a frame for a light vehicle made of a natural fiber reinforced composite pipe of the present invention has a matrix of thermosetting plastics as described in claim 1. It is characterized in that a composite material with a paper thread made of natural fiber is cured and molded into a pipe shape.

The frame for a light vehicle made of natural fiber reinforced composite pipe according to the present invention has a paper thread as described in claim 2,
A mixture obtained by mixing natural fibers and chemical fibers is used. In the frame for a light vehicle made of natural fiber reinforced composite pipe of the present invention, as described in claim 3, the thermosetting synthetic resin is a two-part room temperature curing synthetic resin.

[0009]

The frame for a light vehicle made of natural fiber reinforced composite pipe of the present invention, as described above, is formed by hardening and molding a composite material of a matrix such as thermosetting plastics and a paper base made of natural fiber into a pipe shape. is doing. At that time, the composite material is wound around a core material and cured and molded into a pipe shape. Then, this pipe is joined to a joint made of metal or reinforced plastic to form a frame.

When manufacturing the above-mentioned natural fiber reinforced composite pipe, a paper thread made of natural fibers (or a mixture of natural fibers and chemical fibers) is set in a filament winding device, and thermosetting synthetic resin is set in the device. Impregnated,
Next, the composite material is given an appropriate tension, then the composite material is wrapped around a metal core material, and then the composite material and the core material are heated to the curing temperature of the thermosetting synthetic resin to obtain the thermosetting rigid resin. Is cured, then the core is decoreed, and the molded product is taken out.

As the thermosetting synthetic resin, a two-part room temperature curing synthetic resin may be used. In that case, in order to shorten the curing time, the room temperature curing synthetic resin is heated to an appropriate curing temperature and similarly molded. It should be noted that most of the room temperature curable synthetic resins have no problem even when heated, and when heated, the molding time tends to be shortened in proportion to the temperature.

[0012]

EXAMPLE A frame for a light vehicle made of natural fiber reinforced composite pipe according to the present invention will be described with reference to an example shown in FIGS. First, regarding the paper yarn made from natural fibers, (1) Raw material fiber The main raw material of the paper yarn used as the reinforcing material of the frame in the present invention is pulped vegetable fiber. The plant fiber is selected from wood bast fiber, hemp bast fiber and leaf fiber. In addition to this, a small amount of wood pulp, or synthetic fibers or synthetic pulp known for papermaking are mixed and used.

The wood bast fibers include fibers such as Kozo, Mitsumata, Ganbu and Mulberry. The bark peeled off from these raw trees is steamed with a chemical solution such as alkali to produce pulped fibers. Hemp bast fibers include flax, ramie, hemp, jute, kenaf and the like. Fiber bundles are separated from these stems by a method such as fermentation and steamed with a chemical such as an alkali to produce pulped fibers.

Leaf fibers are produced by removing mesophyll from leaves of Manila hemp and sisal hemp, and steaming the remaining fibers such as veins with a chemical solution such as alkali to produce pulped fibers. The pulp technology from these bast fibers and leaf fibers is described in detail in "Craft Pulp / Non-Wood Pulp", March 1972: Published by The Japan Paper Pulp Technology Association: edited by The Japan Paper Pulp Technology Association.

Known synthetic fibers for papermaking include organic fibers such as rayon, vinylon, polyester, nylon, acrylic and aramid, and inorganic fibers such as glass fiber and carbon fiber. Of these, organic fibers have a fineness of 0.
It has a denier of 1 to 5 and a length of 3 to 13 mm, is well compatible with water, and has a finishing agent attached that allows it to be dispersed in water. The inorganic fiber has a fiber diameter of 3 to 13 μm and a length of 3 to
It is preferably 13 mm.

Synthetic pulp is a fine fibril-like substance obtained by solidifying a polymer from a molten state or a molten state while applying a strong force, and polyolefin pulp and aramid pulp are commercially available. Pulping Example (a) As a bast fiber, an air-dried white leather mitsumata is soaked in water overnight, then placed in a flat kettle, heated with 15% caustic soda and 15 times water, and boiled for 1.5 hours. Deliquoring this
After washing with water and dispersing with a beater, it was bleached with sodium hypochlorite, washed with water, passed through a dust remover and dehydrated to obtain a wet pulp sheet.

Pulping Example (b) As leaf fibers, Manila hemp was placed in a globe-shaped digester with 15% caustic soda and water, and steam-heated under a pressure of 5.5 kg / cm ² for 6 hours to produce pulp. Turn into. This was dewatered, washed with water, bleached with sodium hypochlorite, washed with water, passed through a dust remover and dehydrated to obtain a wet pulp sheet. (2) Papermaking The pulped plant fiber obtained as described above is dispersed in water and beaten to a desired beating degree using a beater or refiner.

If desired, heterogeneous pulped plant fibers are mixed, or synthetic pulp or synthetic fibers are mixed. Alternatively, an additive chemical such as a wet cooperation improving agent is mixed. These are mixed appropriately in a pulper, beater, and compounding pocher. Then, the slurry thus blended is sent to a paper machine, and the paper is dried and wound into a roll in a dry basis weight of 10 to 100 g / m ² . The paper machine is
Various types such as short-mesh, inclined wire type, and circular net can be used. Among them, in the cylinder paper machine, the fibers are oriented in the longitudinal direction, and therefore, there is an advantage that the strength becomes high after slitting into a slender paper thread. Further, the paper creped with a doctor blade during papermaking becomes bulky, and the resin impregnation property is improved. (3) Slit Put the rolled paper on a micro slitter,
Slit into a tape shape with a desired width, make a paper thread, and wind it around a bobbin. A shear cut type slitter is most suitable as a micro slitter.

The thickness and width of the base paper slit into the paper thread are set within a possible range according to the quality design of the composite material. Thickness is within the above range and width is 0.3 to 20 mm
Is preferable as the thread material. From (4) (twisting) In the filament winding process of manufacturing a tubular composite material, in order to perform resin impregnation of the paper thread and stable running and winding after impregnation, the paper thread (twist)
Is preferably added. The thread can be produced without problems by using a normal thread threading machine and setting the speed slightly lower. The appropriate twist depends on the thickness and thickness of the paper thread, but by setting it to be equal to or lower than that of ordinary clothing threads, good results were obtained for resin impregnation, running and workability.

[0020]

[Table 1]

Example of Paper Yarn (a) A mitsumata or wet pulp sheet was dispersed in water, and a slurry was prepared by adding 1% of the absolute dry weight of the wet strength improver. A small amount of a sticky agent was used for paper making with a cylinder paper machine. The properties of the obtained mitsumatari paper were as shown in Example 1 of Table 1. This paper is slit into a width of 2 mm and 400 T / m
Mitsumata paper thread was made by adding Noyori.

Paper yarn example (b) Paper was made in the same manner as in Example 1 of Table 1 but using Manila hemp wet pulp sheet instead of the wet pulp sheet. The characteristics of the obtained Manila paper are as shown in Example 2 of Table 1. Further, it was slit and processed in the same manner as in Example 1 of Table 1 to obtain a manila paper thread.

Example of paper yarn (c) PAN-based carbon fiber having a diameter of 7 μm and a length of 6 mm was mixed with the Manila hemp wet pulp sheet used in Example 2 of Table 1 so as to have a dry weight ratio of 9: 1 and a wet strength. A paper was made in the same manner as in Example 1 of Table 1 by adding an improver. The characteristics of the obtained carbon fiber-mixed paper are shown in Example 3 of Table 1.

Further, in the same manner as in Example 1 in Table 1, slitting and processing were performed to obtain a mixed paper yarn. Since carbon fiber has remarkably high rigidity and adhesiveness is not so high, the results show that the raw yarn properties are not sufficiently reflected in the paper properties and paper yarn strength. However, the penetration of the resin is good, and the effect of the fiber characteristics is recognized as a reinforcing material of the composite material. The paper yarn produced by the above method is set in the raw material feeding part of the filament winding device, and the paper yarn is appropriately tensioned within the tensile strength limit of the paper yarn according to the purpose, and then the resin is placed in the device. After passing through the layer, the thermosetting synthetic resin was impregnated while setting the jig so that the volume content was appropriate, and then the composite material was set on the rotating part of the device, and the metal φ18 mm shown in FIG. The fiber is automatically wound around the core material 1 under conditions such as a fiber laminating angle of 45 °, a laminating number of 15 layers, and a core material rotational speed of 15 m / min, which are input in advance to a computer. This state is shown in FIG. FIG. 2A shows the winding start of the composite material 2, FIG. 2B shows the intermediate folding back, and FIG. 2C shows the winding end of the composite material 2.

Next, the wound composite material 2 and the core material 1 are heated in a rotary heating furnace at a temperature of 80 ° C. for 2 hours to cure the composite material 2 and allow it to cool naturally.
Next, the core material 1 is decoreed, and the molded product (frame for light vehicle vehicle made of natural fiber reinforced composite pipe) is taken out. 3 in FIG. 3 is a frame when applied to a bicycle. As described above, the thermosetting synthetic resin is impregnated with the natural fiber in the filament winding device and wound around the metal core material 1.
Since the thermosetting synthetic resin sufficiently penetrates into the natural fiber by the time the winding of the composite material 2 is completed, the bond between the fiber and the resin becomes strong. Further, the composite material is heated in a heating furnace to the curing temperature of the thermosetting synthetic resin, but in the initial stage of heating, the thermosetting synthetic resin becomes fluid, so that the resin further penetrates into the fiber, The hydroxyl groups of the natural fiber and the hydrogen groups of the thermosetting synthetic resin react positively, the chemical bond becomes stronger, and the bending strength of the composite pipe becomes stronger.

FIG. 4 shows the results of measuring the bending rigidity of the composite pipe. The flexural modulus obtained from the bending test of the composite pipe is as follows. One end of the composite pipe is fixed, two strain gauges are attached 180 degrees symmetrically to the part about 5 mm from the fixed end, and the load is applied to the part 200 mm from the fixed end. It can be calculated from the amount of strain when applied. At this time, at a lamination angle of 45 degrees, the bending elastic modulus of the composite pipe when the volume content rate is 60% (converted value) is about 11,600 MPa. These pipes are assembled by an aluminum joint or the like and joined with an adhesive to form a frame structure.

[0027]

As described above, the light vehicle frame made of natural fiber reinforced composite pipe of the present invention has a matrix such as plastics and natural fibers (or a mixture of natural fibers and chemical fibers).
By using a filament winding device, for example, a composite material with a paper thread created by and is wound around a core material, the composite material is cured and molded into a pipe shape, and the joint material made of metal or reinforced plastic is used. And a joint with an adhesive to form a frame using a natural fiber reinforced composite pipe. The natural fiber reinforced composite pipe, which is the main body of this frame, is used when it is used in a light vehicle frame, such as a bicycle or wheelchair frame, because the matrix such as plastics penetrates into the natural fiber enough to prevent delamination. , It acts to soften the impact at the time of a collision and to minimize the harm to the human body.

Further, the paper thread made of natural fiber (or a mixture of natural fiber and chemical fiber) has a high thread density,
Since the strength of entangled fibers is also strong, the strength of the paper thread alone is also strong, and even if the rupture mode during the strength test such as the tensile test of the composite pipe is broken, it does not lead to rupture, etc. Quite different. In addition, paper yarn made from natural fibers (or a mixture of natural fibers and chemical fibers) has a high elasticity due to the fact that the yarn density increases and elongation occurs when twisted properly. Therefore, the strength of the yarn itself can be increased. In filament winding technology, the fibers are continuous from the beginning to the end. Compared to the case where a commonly used sheet-shaped fiber (prepreg) is wound around a core material and formed, the paper thread has a higher density than the sheet. Higher weight, more fiber can be put into the product, which results in lighter weight and higher pipe rigidity. From the above, these light vehicle frames made of natural fiber reinforced composite pipes are lighter in weight, have better impact resistance and are more comfortable to ride than frames made of metal and carbon fiber reinforced plastic pipes.

In particular, bast fibers such as Mitsumata and leaf fibers are used as the natural fibers, and thermosetting synthetic resin is used as the synthetic resin to impregnate each other in the resin layer in the filament winding device, and then the composite material is used. It is wound around the metal core attached to the rotating part of the, and the wound composite material and core are heated to the curing temperature of the thermosetting resin in a heating furnace to cure, and then the core is decoreed. Then, when the molded product is taken out, the following effects are achieved in addition to the above effects.
That is, in the first stage of heating, the thermosetting synthetic resin is fluid, and the hydroxyl groups of the natural fiber and the hydrogen groups of the thermosetting synthetic resin react positively to strengthen the chemical bond. It was Therefore, the impact resistance of the natural fiber reinforced composite pipe is improved, and the flexibility is increased.

Further, even when the fiber is broken, since the adhesion between the fiber and the resin is high, there is an effect that it does not show a brittle breakage form and the risk of causing harm to a human body is small.

[Brief description of drawings]

FIG. 1 is a perspective view showing a core material used for manufacturing a light vehicle frame made of a natural fiber reinforced composite pipe of the present invention.

FIG. 2 is an explanatory view showing a winding state of a composite material around a core material in a filament winding device.

FIG. 3 is a side view showing an embodiment of a light vehicle frame made of natural fiber reinforced composite pipe of the present invention.

FIG. 4 is an explanatory diagram showing a measurement result of bending rigidity of a composite pipe.

[Explanation of symbols]

1 core material 2 composite material 3 natural fiber reinforced composite pipe made of light vehicle frame pipe

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hirotaka Ogawa, Hiroshi Ogawa, 501 Shiogamaguchi, Tenpaku-ku, Nagoya, Aichi Prefecture Meijo University, Faculty of Science and Engineering, Department of Transportation Machinery (72) Inventor Akio Suzumura 2-12, Ookayama, Meguro-ku, Tokyo No. 1 Tokyo Institute of Technology, Faculty of Engineering, Department of Industrial Machinery Engineering (72) Inventor, Kotaro Endo, 422 Maeno, Mino City, Gifu Prefecture Daifuku Paper Co., Ltd. (72) Masamichi Saiu, 422, Maeno City, Mino City, Gifu Daifuku Paper Co., Ltd. (72) Inventor Kenji Sakaida 3-25-23 Takanawa, Minato-ku, Tokyo Keikyu Second Building Asahi Engineering Co., Ltd.

Claims (3)

[Claims] 1. A frame for a light vehicle made of a natural fiber reinforced composite pipe, characterized in that a composite material of a matrix such as thermosetting plastics and a paper thread made of natural fiber is cured and molded into a pipe shape. .. 2. The frame for a light vehicle made of natural fiber reinforced composite pipe according to claim 1, wherein a mixture obtained by mixing natural fiber and chemical fiber is used for the paper thread. 3. The frame for a light vehicle made of a natural fiber reinforced composite pipe according to claim 1, wherein a two-part room temperature curing synthetic resin is used as the thermosetting synthetic resin.