JP2514836B2 - Piston pin - Google Patents

Description

TECHNICAL FIELD The present invention relates to a carbon fiber reinforced resin piston pin that maximizes a weight reduction effect and optimizes fiber orientation.

The biston pin connects the piston and the connecting rod in the internal combustion engine.

[Prior art and problems]

The piston pin is required to have high rigidity and high strength at the same time so as to be less deformed under load.
On the other hand, since the piston pin is used at high temperature, it must have excellent dimensional stability under repeated heat loads, and the outer peripheral surface of the pin slides,
It is also necessary to have excellent sliding properties.

Various proposals have hitherto been made in order to meet these requirements. For example, JP-A-59-80564 and JP-A-60-60
-78164 proposes the orientation angle of the reinforcing fiber in the fiber-reinforced metal piston pin, but since this material is a fiber-reinforced metal, it has a higher density than the carbon fiber-reinforced resin and further increases the weight reduction. In order to achieve high rigidity, high strength, dimensional stability under high temperature, made of carbon fiber reinforced resin,
It was necessary to obtain a piston pin with well-balanced sliding characteristics. Regarding the piston pin made of carbon fiber reinforced resin, JP-A-57-10747, JP-A-54-150709, JP-A-55-17952, etc. have already been proposed, but each of the above characteristics It has not been possible to clearly propose the configuration of the pipe including the fiber orientation angle, which should be provided to enhance the weight reduction effect.

[Object of the Invention]

It is known that if the piston pin of an internal combustion engine becomes lighter, the moment of inertia of the piston pin decreases, so that the weight of the entire internal combustion engine can be significantly reduced and the performance improves.
In addition to the performance improvement of the internal combustion engine, for example, in the case of a vehicle, when the internal combustion engine becomes lighter, the weight of the structure holding the same can be reduced, and as a result, the performance of the vehicle is improved. Therefore, weight reduction of the piston pin of an internal combustion engine is very important.

Against the background described above, the present invention provides the largest carbon weight reduction effect among various studies using the high specific strength and high specific rigidity of the carbon fiber reinforced resin and using the same for the piston pin. The purpose of the invention is to obtain the structure of a piston pin made of fiber reinforced resin, that is, to improve the characteristics required as a piston pin by optimizing the orientation of carbon fibers.

[Structure and Action of Invention]

 The present invention is as follows.

In a pipe composed of a pipe body and an outer surface layer, the pipe body is made of a carbon fiber reinforced resin and has an inner layer having a winding angle of ± 40 ° to ± 90 ° and an outer layer having a winding angle of ± 20 ° to ± 30 °. A piston pin, characterized in that the pipe outer surface layer is made of a material having a hardness higher than that of the carbon fiber reinforced resin.

In the present invention, the winding angle means an acute angle formed by a straight line parallel to the axis of the pipe on the outer peripheral surface of the pipe and the direction of the reinforcing fiber.

The present invention provides a piston pin having all the properties required for a piston pin, namely, high rigidity, high strength, dimensional stability under high temperature, and sliding properties. High rigidity,
The winding angle of the reinforcing fiber to achieve high strength is ± 20 ° ~
It is necessary to be ± 30 °, and in order to improve the sliding characteristics, it is necessary to coat the outer surface of the pipe made of carbon fiber reinforced resin with a hard material. The hard material mentioned here is hard metal, ceramics or the like. Further, for coating, a thin steel pipe may be externally inserted, and plating or thermal spraying is also possible. However, at this time, if the direction of the reinforcing fiber of the pipe made of carbon fiber reinforced resin is not properly selected, the carbon fiber reinforced resin will contract due to the heat cycle load applied to the piston pin at room temperature or 180 ° C, and the outer surface will be hard. This may cause peeling from the material or a gap between the piston pin and the pin receiver, resulting in trouble. In order to prevent this peeling or the like, in the present invention, the winding angle of the reinforcing fiber is ± 40 ° to ± 90 ° as the inner layer, and the winding angle is ±
By making the layer of 20 ° to ± 30 ° the outer layer, high rigidity,
It is possible to obtain a piston pin having high strength, dimensional stability under high temperature, and excellent sliding characteristics. Then, to further describe, the layer with a winding angle of ± 40 ° to ± 90 ° is provided inside, and the layer with a winding angle of ± 20 ° to ± 30 ° that gives high rigidity and high strength is provided outside. In the case of being provided in, the flattening of the pipe at the time of bending deformation is prevented, and high rigidity and high strength are given to the entire pipe. At this time, if the angle of the outer layer is less than ± 20 °, the strength is mainly insufficient, and if it exceeds ± 30 °, the rigidity is mainly insufficient, so that the winding angle of the outer layer needs to be ± 20 ° to ± 30 °. At the same time, if the winding angle of the inner layer is less than ± 40 °, the dimensional stability after thermal cycling is insufficient, and if the order of the inner and outer layers is reversed, many cracks will occur in the deformed product. Therefore, as in the present invention, it is necessary to form an inner layer having a winding angle of ± 40 ° to ± 90 ° and an outer layer having a winding angle of ± 20 ° to ± 30 °.

In the present invention, the reinforcing fiber is a carbon fiber, which is limited to this in view of high specific elasticity and high specific strength. Needless to say, higher rigidity can be obtained by using carbon fibers of high elasticity, and it is more effective to use carbon fibers having different elastic moduli and strengths as necessary.

The fiber-reinforced matrix resin is an epoxy resin, a phenol resin, a bismaleimide resin, or the like.

The carbon fiber reinforced resin pipe of the present invention can be easily obtained by a usual FRP molding method such as a filament winding method or a rolling method in which a prepreg sheet is wound around a mandrel.

 The present invention will be described with reference to the drawings.

As shown in FIG. 1, an acute angle θ formed by a straight line parallel to the axis of the pipe on the outer peripheral surface of the pipe and the direction of the reinforcing fiber.
2 is an inner layer having a winding angle of ± 40 ° to ± 90 ° in order to obtain dimensional stability after thermal cycle loading, as shown in FIG. As shown in Fig.2, it is mainly composed of an outer layer with a winding angle of ± 20 ° to ± 30 ° in order to enhance strength and rigidity, and its outer surface is mainly for improving sliding characteristics as shown in Fig. 2. The piston pin is made of a material having a hardness higher than that of the carbon fiber reinforced resin.

[Examples and Comparative Examples]

Example 1 A piston pin was manufactured by the filament finding method as follows. That is, for a core metal with a diameter of 7.5 mm,
A carbon fiber (Bethfight HTA-7-6000 manufactured by Toho Rayon Co., Ltd.) impregnated with an epoxy resin in advance was wound. The winding angle at this time is as shown in FIG. The positive and negative signs of the winding angle θ are positive in the counterclockwise direction. After winding until the winding angle θ becomes ± 70 ° and the outer diameter becomes φ14 mm, then wind until the winding angle θ becomes ± 20 ° and the outer diameter becomes φ21 mm. did. This was heat-cured, demolded, and then polished to form the outer surface of the pipe with a hard chrome plating layer, and then the outer diameter of the pipe was set to φ20 mm. Then, this was cut into a length of 70 mm to obtain a piston pin shown in FIG. In FIG. 2, 1 is a layer having a reinforcing fiber winding angle θ of ± 70 °, 2 is a layer having a reinforcing fiber winding angle θ of ± 20 °, and 3 is a carbon fiber reinforced resin. The hard chrome plating layer which comprises the outer surface layer of a pipe made from is shown.

Example 2 In the same manner as in Example 1, carbon fibers (Vesfight HTA-7-6000 manufactured by Toho Rayon Co., Ltd.) pre-impregnated with an epoxy resin so that the winding angle θ is ± 70 ° have an outer diameter of φ1.
After winding up to 4 mm, carbon fiber pre-impregnated with epoxy resin (Vesfight HMS-40-made by Toho Rayon Co., Ltd.) until the winding angle θ becomes ± 20 ° and the outer diameter becomes φ21 mm. 6000) was wound. Subsequent operations were the same as in Example 1 to obtain a piston pin.

Comparative Example 1 A pipe was formed in the same manner as in Example 1 so that the winding angle θ of the reinforcing fiber was ± 20 ° over the entire wall thickness, and the subsequent operation was the same as in Example 1 to obtain a piston pin. .

Comparative Example 2 In the same manner as in Comparative Example 1, the winding angle θ of the reinforcing fiber was 0.
°, ± 10 °, ± 30 °, ± 40 °, ± 50 °, ± 70 °, ± 90 °
Then, a pipe was obtained, and the subsequent operation was carried out in the same manner as in Example 1 to obtain a piston pin.

Measurement and Evaluation of Properties The piston pins obtained as described above were evaluated for bending properties closely related to the winding angle of the reinforcing fiber and dimensional stability after thermal cycling. First, the strength and rigidity of the piston pin were evaluated by conducting a bending test by the method as shown in FIG. The measurement results are shown in FIGS. 4 and 5. The strength is large when the wrapping angle θ of the reinforcing fiber with a large bending fracture load is ± 20 ° to ± 50 °, and the rigidity is ± 10 ° with a large load that causes bending bending (1 mm) per unit length.
High when it is ~ ± 30 °. Therefore, it is understood that it is necessary to orient the reinforcing fibers in the range of ± 20 ° to ± 30 ° in order to enhance the strength and rigidity. On the other hand, the same piston pin was placed under high temperature (180 ° C.), and the change with time of the outer diameter of the pipe was examined. The dimension measurement was carried out at room temperature. The measurement results are shown in FIG. The dimensional change of the pipe is small when the winding angle θ is ± 50 °, ± 70 °, ± 90 °. But these are
It is not suitable for piston pins because of its low strength and rigidity described above. That is, from the results of FIGS. 4 to 6, Example 1
In the carbon fiber reinforced resin pipe like the piston pin of the present invention shown in Example 2, the winding angle θ of the reinforcing fiber is ± 40 ° to ± 90 ° and the winding angle of the reinforcing fiber is ± 20. And an outer layer that is between ± 30 °, and
It has been proved that the outer surface of the pipe made of a material having a hardness higher than that of the fiber reinforced resin is most suitable for the piston pin.

〔The invention's effect〕

The relationship between each piston pin and each characteristic described above is
These are summarized in the table. In the table, ◯ indicates that the characteristics are excellent, and x indicates that the characteristics are inferior.
The piston pin according to the invention excels in all properties.

[Brief description of drawings]

FIG. 1 shows the winding angle θ of the reinforcing fiber in the present invention. FIG. 2 shows an example of the piston pin of the present invention. In the figure, 1 is a layer having a carbon fiber winding angle of ± 70 °, 2 is a layer having a carbon fiber winding angle of ± 20 °, and 3 is an outer surface of a carbon fiber reinforced resin pipe The hard chrome plating layer which comprises a layer is shown. FIG. 3 shows a schematic view of a bending test device for evaluating strength and rigidity of a piston pin. In the figure, 4 indicates a test piece. FIG. 4 shows the breaking load for each piston pin as a result of the bending test performed by the method shown in FIG.
In the figure, ± 20 ° / ± 70 ° (1) indicates that obtained in Example 1, and ± 20 ° / ± 70 ° (2) indicates that obtained in Example 2. Fig. 5 shows the unit bending deflection length (1mm) for each piston pin as a result of the bending test conducted by the method shown in Fig. 3.
It shows the load for. Similar to FIG. 4, in the figure, ± 20 ° / ± 70 ° (1) was obtained in Example 1, and ± 20 ° / ± 70 ° (2) was obtained in Example 2. Is shown. FIG. 6 shows the relationship between the holding time of each piston pin at high temperature (180 ° C.) and the change in outer diameter of the pin. Similar to FIGS. 4 and 5, in the figures, ± 20 ° / ± 70 ° (1) is the one obtained in Example 1, and ± 20 ° / ± 70 ° (2) is the same. The one obtained in Example 2 is shown.

Claims (1)

(57) [Claims] 1. A pipe comprising a pipe body and an outer surface layer, wherein the pipe body is made of carbon fiber reinforced resin and has an inner layer having a winding angle of ± 40 ° to ± 90 ° and a winding angle of ± 20 °.
A piston pin comprising an outer layer of ± 30 ° and an outer surface layer of the pipe made of a material having a hardness higher than that of the carbon fiber reinforced resin.