KR20130012842A - Bicycle frame haing the carbon fiber and the packed layer - Google Patents

Abstract

PURPOSE: A bicycle frame using a carbon fiber and filler and a method for manufacturing the same are provided to fill an empty space inside a carbon fiber composite material with the filler, thereby enhancing bending stiffness and impact resistance. CONSTITUTION: A bicycle frame using a carbon fiber and filler is as follows. A carbon fiber composite material is laminated inside bicycle molds in both sides(S100). The filler is charged on the laminated carbon fiber composite material(S200). The bicycle molds in both sides are coupled so that the carbon fiber and filler are primarily molded by increasing temperature(S300). The temperature is slowly increased so that the carbon fiber and filler are secondarily molded at temperature higher than the first molding temperature(S400). The bicycle molds are naturally cooled, and a molded article is separated from the mold so that a product is completed(S500). [Reference numerals] (AA) Start; (BB) End; (S100) Laminating a prepreg of carbon fiber composite material in a manufactured bicycle mold; (S200) Charging a filler; (S300) Coupling the mold and primarily molding; (S400) Secondarily molding; (S500) Naturally cooling and removing a product

Description

Bicycle frame using carbon fiber and filler and its manufacturing method {BICYCLE FRAME HAING THE CARBON FIBER AND THE PACKED LAYER}

The present invention relates to a bicycle frame using carbon fiber and filler and a method for manufacturing the same. More specifically, the structure and the material of the frame forming the basic skeleton of the bicycle in a bicycle for athletes as well as general bicycles used as a driving means, The present invention relates to a bicycle frame using carbon fiber and filler and a method of manufacturing the same.

Currently, bicycles are produced using carbon fiber composite materials. That is, a carbon fiber composite material is used as a material of a bicycle frame in the form of a pipe forming a bicycle body.

Carbon fiber is lighter than metal and has excellent elasticity and strength because the weight of oxygen, hydrogen, nitrogen, and other molecules are lost in the process of manufacturing carbon fiber. However, carbon fiber is not used alone, but is used as a composite material used with a substrate such as resin. Currently, carbon fiber composite material is used by combining carbon fiber, which is used as a bicycle frame, and carbon fiber, a material having excellent elasticity and strength, with an epoxy resin, which is a thermosetting resin.

Carbon fiber composite material has a strong rigidity compared to the weight of the bicycle has been applied to a variety of applications, such as mountain and road. Most bicycle companies have been manufacturing carbon fiber composite material in the form of a tube, that is, a hollow form as shown in FIG. 1, but recently, in order to reinforce the rigidity of the bicycle frame due to the increase of bicycles in rough terrain such as mountainous terrain, As shown in FIG. 2, a web (called a 'web' or a reinforcing bar) is inserted in the middle of a tubular carbon fiber composite material to reinforce bending stiffness.

However, there is a disadvantage that the strength of the carbon fiber composite material (hereinafter, referred to as the 'carbon fiber composite material') in which epoxy resin is bonded is weak compared to elasticity and tensile strength. Therefore, when manufacturing a bicycle frame using a carbon fiber composite material, it is possible to manufacture a bicycle lighter than metal, but the impact strength is weakened, fatigue resistance is weak. In the case of a bicycle that receives a lot of load while driving, such as MTB (mountain bike), there is a possibility that the bicycle frame is damaged by the impact while the bicycle is running, and if the bicycle frame is damaged, it may lead to a big accident.

A process of manufacturing a bicycle frame using a composite material of carbon fiber bonded to a conventional epoxy resin is as follows.

3 is a view showing a conventional method of forming a carbon fiber composite bicycle frame using a pressure bag (silicon tube).

In general, in order to manufacture a carbon fiber composite bicycle frame, after laminating (ie laminating) the carbon fiber composite prepreg to a prefabricated frame (molding mold), a pressure suitable for the shape of the bicycle frame mold Molding is carried out with a bag (silicon tube). That is, according to the shape of the bicycle frame mold, by putting different pressure bag (silicon tube) to expand the air in the pressure bag (silicon tube) to increase the adhesion between the bicycle mold mold and the carbon fiber composite material prepreg. When the pressure bag (silicon tube) is expanded, the laminated carbon fiber composite prepreg is molded along the mold shape.

Here, the 'carbon fiber composite prepreg' refers to a product in which carbon fiber is impregnated with resin (ex. Epoxy resin) evenly between carbon fibers in a certain content. It means a thin film with fluidity. Each of the two molds of the bicycle is laminated in one or more layers, and a pressure bag (silicon tube) is placed between both mold molds, and both mold molds are closed. Then, air is injected into the pressure bag and carbon The fiber composite prepreg is molded.

If the advantages of the conventional molding method, the resin (ex, epoxy) in the carbon fiber is impregnated in advance, so that the fiber arrangement is not scattered, and impregnated the product is impregnated once again, so that the adhesion between the products can be increased, but the bicycle Since pressure bag has to be manufactured separately according to the frame shape, there is a disadvantage in that it increases production cost and complexity of the production process.

The present invention is to solve the above problems, it is an object of the present invention to provide a bicycle frame and a method of manufacturing the same that can increase the fatigue strength, increase the flexural strength, which is a disadvantage of the carbon fiber.

In order to achieve the above object, the manufacturing method of the bicycle frame of the present invention

i) laminating the carbon fiber composite material inside both bicycle mold molds,

ii) filling the filler onto the laminated carbon fiber composite material,

iii) fastening the upper and lower bicycle mold molds on both sides, and slowly warming up the first mold,

iv) maintaining the temperature slowly to a temperature higher than the temperature of the primary molding to secondary molding, and

v) after the natural cooling, the step of deserting the bicycle mold mold to complete the product.

According to a preferred embodiment, the carbon fiber composite material is in a prepreg state in which carbon fibers are impregnated with an epoxy resin.

According to a preferred embodiment, the filler is 5 to 15% by weight of aramid chopped fibers (50% by weight), 50% by weight of the noble block epoxy resin, 25 to 40% by weight of bisphenol A epoxy resin, 1 to 3% by weight of blowing agent 5-15 weight part of hardening | curing agents are added to 100 weight part of main parts containing a.

According to a preferred embodiment, the primary molding conditions are a temperature of 70 to 90 degrees, 30 minutes to 2 hours, the secondary molding conditions are a temperature of 110 to 140 degrees, 1 hour to 3 hours.

The bicycle frame according to the preferred embodiment of the present invention is characterized in that the carbon fiber is impregnated with an epoxy resin impregnated with aramid fibers inside the carbon fiber composite material impregnated with the epoxy resin.

According to a preferred embodiment, the bicycle frame,

 An inner cylinder formed of a carbon fiber composite material impregnated with carbon fibers impregnated with an epoxy resin, a filler formed of an epoxy resin formed on the inner cylinder and including a small cut aramid fiber, the filler being formed on the filler, wherein the carbon fibers are epoxy It includes an outer cylinder formed of a carbon fiber composite material impregnated with the resin.

As described above, the bicycle frame of the present invention is filled with a filler in the empty space inside the carbon fiber composite material, and, if the bicycle frame is empty when the impact is applied to the bicycle frame (about 0.3 weight) If present, the bending stiffness and impact strength can be increased. Therefore, even if the bicycle frame (carbon fiber composite material) is a little damaged by the filler filled in the bicycle frame has a better effect on preventing accidents.

That is, the bicycle frame of the present invention can manufacture a bicycle frame improved by preventing the damage, fatigue resistance, flexural strength, flexural elasticity due to the instantaneous impact due to the use of the filler compared to manufacturing the bicycle frame using only carbon fiber. There is an advantage.

1 is a cross-sectional view of an example of a bicycle frame using a conventional carbon fiber composite material.
2 is a cross-sectional view of another example of a bicycle frame using a conventional carbon fiber composite material.
3 is a cross-sectional view showing a method of forming a carbon fiber composite bicycle frame in a conventional manner.
4 is a cross-sectional view of a bicycle frame filled with a filler in accordance with a preferred embodiment of the present invention.
5 is a cross-sectional view showing a method of forming a bicycle frame filled with a filler in accordance with a preferred embodiment of the present invention.
Figure 6 is a flow chart illustrating a method of forming a bicycle frame filled with a filler in accordance with a preferred embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, it will be described in more detail the bicycle frame and its manufacturing method of the present invention.

5 is a cross-sectional view showing a method of forming a bicycle frame filled with a filler in accordance with a preferred embodiment of the present invention.

Referring to FIG. 5, the bicycle frame is a cylindrical frame in which carbon fibers are impregnated with an epoxy resin impregnated with aramid fibers and filled with a filler inside the carbon fiber composite material impregnated with an epoxy resin. As described above, the carbon fiber composite material is a form in which carbon fiber is impregnated with an epoxy resin and has a fluidity of prepreg. The prepreg is wound on a roll, and since there is a resin, it does not fall off when it is wound on the roll. When prepreg is laminated, the release paper is removed and laminated (laminated).

The filler is composed of 5-15 wt% of aramid chopped fiber, 50-wt% of a noblel-based epoxy resin, 25-40 wt-% of bisphenol A epoxy resin, and 1-3 wt% of foaming agent. 5-15 weight part of hardening | curing agents are added to a part and it consists of.

As such, when manufacturing the bicycle frame by inserting a filler therein, due to the adhesion between the filler and the carbon fiber composite material, it is possible to increase the flexural strength and flexural elasticity of the bicycle frame. In other words, when the carbon fiber composite prepreg is cured, the contact strength between the carbon fiber composite prepreg and the filler may be increased, and an epoxy filler containing aramid chopped fiber may be used. If there is an advantage to increase the strength itself.

Hereinafter, a method of manufacturing the bicycle frame of the present invention will be described in detail.

6 is a flowchart illustrating a method of forming a bicycle frame filled with a filler in accordance with a preferred embodiment of the present invention.

First, after manufacturing the bicycle mold mold, the carbon fiber composite material is laminated in both bicycle mold mold (S100). The method of laminating the carbon fiber prepreg on the bicycle mold mold is the same as in the case of not using the filler, that is, the conventional method of FIG. However, instead of the pressure bag (silicon tube) used to closely adhere the laminated carbon fiber composite material in the conventional method (see FIG. 3), the pressure bag may be manufactured using a composite filler having expandability according to molding conditions. The bicycle frame can be molded and manufactured without the need.

That is, the filler is then filled on the laminated carbon fiber composite material (S200). Filling the interior therein, when manufacturing a carbon fiber composite bicycle frame, there is no need to produce a pressure bag (silicon tube) that depends on the frame shape. That is, when the prepreg is laminated in the bicycle frame mold mold and then the filler is molded, the prepreg is pushed against the mold mold surface by molding the prepreg due to the expansion property of the filler.

The filler is 100 parts by weight of 5-15% by weight of aramid chopped fiber, 50% by weight of a noblock-type epoxy resin, 25-40% by weight of bisphenol A epoxy resin, and 1-3% by weight of a blowing agent. 5-15 weight part of hardening | curing agents are added to and it consists of.

Filler has the property of expanding the volume according to the molding cycle to fill the appropriate amount of the filler. Too little filler can create voids, and too much filler can increase the density of the filler and increase the overall weight of the bike frame. Since the filler changes depending on the molding conditions and the mold, the amount of filler may be adjusted for each frame.

Next, after fastening both upper and lower bicycle mold molds, the first step is to slowly warm up (S300). Primary molding conditions are a temperature of 70-90 degrees and 30 minutes-2 hours. Preferably, the temperature is slowly raised to about 80 degrees at room temperature for 30 minutes, followed by heating for about 30 minutes while maintaining 80 degrees. The reason for the primary molding heating at about 80 degrees lower than the secondary molding temperature is that the epoxy resin in the filler expands to a certain degree to fill the empty space therein so that no bubbles or spaces are formed in the filler, thereby improving the completeness of the product. To increase.

 Next, by heating the mold, it is a step of secondary molding (S400). Secondary molding conditions are heated to a temperature higher than the first to about 110 ~ 140 degrees, about 1 to 3 hours. Preferably, the temperature is slowly raised to 125 degrees for 30 minutes, and then maintained at a temperature of 125 degrees for about 60 minutes.

Next, after the mold mold is naturally cooled, it is deserted in the bicycle mold mold to complete the product (S500).

[ Example ]

Example  One

The carbon fiber composite material was laminated on the bicycle mold mold prepared in advance. The carbon fiber composite material prepreg (USN 150) had a thickness of about 0.15 mm, and ten prepregs were laminated on the upper and lower bicycle mold dies.

As a filler, 600g of noblock epoxy, 280g of bisphenol A epoxy, 20g of blowing agent, and 100g of aramid chopped fiber were added to make a filler by adding 70g of a hardener, and then it was put on the prepreg. In this case, the filler is in a state like fluidized mass (ex. Clay). In anticipation of foaming, the filler was made to fill approximately 90% of the semi-cylindrical bicycle mold mold.

Next, after fastening both upper and lower bicycle mold molds, the temperature was slowly increased to about 80 degrees for 30 minutes at room temperature, and then firstly heated for about 30 minutes while maintaining 80 degrees. Thereafter, the temperature was slowly raised again to the temperature of 125 degrees for 30 minutes, and then maintained at the temperature of 125 degrees for about 60 minutes. After the molding was finished, the mold mold was naturally cooled and then deserted from the bicycle mold mold. Thus, a pipe filled with a filler in a 1.5 mm thick carbon fiber composite pipe was completed.

Example  2

Pipes were manufactured in the same manner as in Example 1, except that eight prepregs were stacked on upper and lower bicycle mold molds. Thus, a pipe filled with a filler in a 1.2 mm thick carbon fiber composite pipe was completed.

Example  3

Pipes were prepared in the same manner as in Example 1, but first, six sheets of prepregs were stacked on upper and lower bicycle mold molds, and the fillers were filled thereon, and then four sheets of prepregs were laminated on the fillers. Thus, a pipe filled with filler was completed in a carbon fiber composite pipe having a sandwich structure of 9 mm thickness and 6 mm thickness.

Comparative example

As before, the prepregs were laminated on the upper and lower bicycle mold molds, the Pressure Bag was inserted, and both molds were fastened. Then, air was added to the pressure bag. This completed a hollow 1.5mm carbon fiber composite pipe.

As a result of comparing the pipes prepared by Examples 1 to 3 with the pipes produced by Comparative Examples, the flexural strength was much higher in Examples 1 to 3 than in Comparative Examples, and Examples 1 and 3 were compared. 3 was the best flexural strength. Flexural strength did not have a big difference in Examples 1 and 3, but in Example 3, since the outer and inner surfaces of the carbon fiber composite material must be manufactured, there was a problem that production efficiency was not good because the production process was difficult.

As a result, the bicycle frame is made by using a composite filler containing small aramid chopped fibers, which absorbs shock while reducing the amount of carbon fibers when compared to a frame that does not use a filler when manufacturing a bicycle frame using a carbon fiber composite material. Life expectancy and safety can be secured.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention may be embodied otherwise without departing from the spirit and scope of the invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the scope of the present invention, but are intended to be illustrative, and the scope of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of the claims should be construed as being included in the scope of the present invention.

Claims (7)

Method for manufacturing a bicycle frame.
i) laminating the carbon fiber composite material inside both bicycle mold molds,
ii) filling the filler onto the laminated carbon fiber composite material,
iii) fastening the upper and lower bicycle mold molds on both sides, and slowly warming up the first mold,
iv) maintaining the temperature slowly to a temperature higher than the temperature of the primary molding to secondary molding, and
v) after the natural cooling, the step of deserting the bicycle mold mold to complete the product comprising the step of manufacturing a bicycle frame. The method of claim 1,
The carbon fiber composite material is a method of manufacturing a bicycle frame, characterized in that the carbon fiber is in a prepreg impregnated with an epoxy resin. The method of claim 1,
The filler is composed of 5-15 wt% of aramid chopped fiber, 50-wt% of a noblel-based epoxy resin, 25-40 wt-% of bisphenol A epoxy resin, and 1-3 wt% of foaming agent. 5-15 weight part of hardening | curing agents were added to the part, The manufacturing method of the bicycle frame characterized by the above-mentioned. The method of claim 1,
The primary molding conditions are a temperature of 70 ~ 90 degrees, 30 minutes ~ 2 hours,
The secondary molding conditions are a temperature 110 ~ 140 degrees, 1 hour to 3 hours, characterized in that the manufacturing method of the bicycle frame. In the bicycle frame,
A bicycle frame, wherein a carbon fiber is impregnated with an epoxy resin, and an epoxy resin impregnated with aramid fibers is filled therein with a filler. 6. The method of claim 5,
The filler is composed of 5-15 wt% of aramid chopped fiber, 50-wt% of a noblel-based epoxy resin, 25-40 wt-% of bisphenol A epoxy resin, and 1-3 wt% of foaming agent. 5-15 weight part of hardening | curing agents were added to the part, The bicycle frame characterized by the above-mentioned. 6. The method of claim 5,
The bicycle frame
An inner cylinder, hollowed out and formed of a carbon fiber composite material in which carbon fibers are impregnated with an epoxy resin,
Filler formed on the inner cylinder, formed of an epoxy resin comprising a small cut aramid fibers,
A bicycle frame formed on the filler, the carbon frame comprising an outer cylinder formed of a carbon fiber composite material impregnated with an epoxy resin.

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