JPH02113170A - Piston pin - Google Patents

Abstract

PURPOSE:To obtain a piston pin which is excellent in strength and rigidity and reduced in weight by forming a pipe main body by an inner layer and an outer layer respectively having specified winding angles, and forming an outer surface layer by material with hardness higher than that of carbon fiber reinforced resin. CONSTITUTION:Carbon fiber impregnated with epoxy resin is wound round a core bar with a winding angle of + or -40 deg.-+ or -90 deg. to form an inner layer, and an outer layer 2 with a winding angle of + or -20 deg.-+ or -30 deg. is formed on the outside of the inner layer. After that, the core bar and the inner and outer layers are heated, hardened and polished, and a hard chrome plating layer 3 is formed on the outer surface thereof. Accordingly, a piston pin can be excellent in strength, rigidity, dimensional stability and sliding characteristic and reduced in weight.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention provides a piston pin made of carbon fiber reinforced resin that maximizes the miniaturization effect and optimizes fiber orientation.

A piston pin connects a piston pin and a connecting rod in an internal combustion engine.

[Prior art and problems]

Piston pins are required to have high rigidity so that there is little deformation under load, and at the same time, high strength is also required. On the other hand, since piston pins are used at high temperatures, they must have excellent dimensional stability under repeated thermal loads, and since the outer circumferential surface of the bottle slides, they must have good sliding characteristics. It is also necessary to be excellent.

Various proposals have been made to meet these demands. For example, in JP-A-59-80564 and JP-A-60-711164, the orientation angle of reinforced IIN in a fiber-reinforced metal piston pin is proposed, but since this material is a fiber-reinforced metal, It has a higher density than carbon mH-reinforced resin, and in order to further reduce the weight, we use a piston pin made of carbon fiber-reinforced resin that has high rigidity, high strength, dimensional stability under high temperatures, and vE dynamic characteristics in a well-balanced manner. It was necessary to obtain it.

Piston pins made of carbon fiber reinforced resin have already been disclosed in Japanese Unexamined Patent Publication No. 57-10747 and Utility Model Application No. 54-150.
Although publications such as Publication No. 709 and Japanese Utility Model Application Publication No. 55-17952 have been proposed, no clear proposals have been made on the structure of the pipe, including the fiber orientation angle, which should have the above-mentioned characteristics and enhance the weight reduction effect. It wasn't.

C) Object of the Invention) It is known that if the piston pin of an internal combustion engine becomes lighter, its moment of inertia will be reduced, which will greatly reduce the weight of the entire internal combustion engine and improve its performance. In addition to this improvement in the performance of internal combustion engines, in the case of vehicles, for example, as the internal combustion engine becomes lighter, the structure that holds it becomes lighter.
This also makes it possible to increase the number of employees, which in turn leads to improved vehicle performance. Therefore, reducing the weight of piston pins for internal combustion engines is very important.

Against this background, while various studies have been made to utilize the high specific strength and high specific rigidity of carbon fiber reinforced resins for use in piston pins, the present invention is based on carbon fiber reinforced resin that can achieve the greatest weight reduction effect. The purpose of this invention is to obtain a structure of a piston pin made of a 1iui reinforced resin, that is, to improve the characteristics necessary for a piston pin by optimizing the orientation of carbon fibers.

[Structure and operation of the 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 carbon fiber reinforced resin and has an inner layer with a winding angle of ±40' to ±90' and a winding angle of ±20' to ±3.
1. A piston pin characterized in that the pipe outer surface layer is made of a material having a higher hardness than the carbon fiber reinforced resin.

In the present invention, the winding angle refers to an acute angle between a straight line on the outer circumferential surface of the pipe parallel to the axis of the pipe and the reinforcing fiber direction.

The present invention provides a piston pin that has all the characteristics necessary for a piston pin, that is, high rigidity, high strength, dimensional stability at high temperatures, and impulse characteristics. The winding angle of reinforced JIH is ±20' to achieve high rigidity and strength.
~±30', and in order to improve the impulse characteristics, it is necessary to cover the outer surface of the pipe made of carbon fiber reinforced resin with a hard material.

The hard materials mentioned here include hard metals, ceramics, and the like. Further, for covering, a thin A4 pipe may be inserted, or plating or thermal spraying may be used. However, if the reinforcing direction of the pipe made of carbon fiber-reinforced resin is not selected appropriately, the carbon fiber-reinforced resin will shrink under the thermal cycle load applied to the piston pin at room temperature to 180°C, causing the outer surface to deteriorate. This may cause problems such as separation from the hard material or a gap between the piston pin and the bottle holder. In order to prevent this peeling etc., in the present invention,
By using the reinforcing fiber layer with a winding angle of ±40" to ±90' as the inner layer and the layer with a winding angle of ±20 to ±30" as the outer layer, high rigidity, high strength, and dimensional stability under high temperatures are achieved. This makes it possible to obtain a piston pin with excellent impulse characteristics.Moreover, if this winding angle is ±
A layer of 40゛~±90' is provided inside, and high rigidity,
If a layer with a winding angle of ±20° to ±30°, which provides high strength, is provided on the outside, it will prevent the pipe from becoming flattened during bending deformation, and the entire pipe will have high rigidity and strength. It will be given to you. At this time, the angle of the outer layer is ±
If it is less than 20°, the strength will mainly be insufficient, and if it exceeds ±30°, the rigidity will mainly be insufficient, so the winding angle of the outer layer should be ±
It needs to be between 20' and ±30'.

At the same time, if the winding angle of the inner layer is less than ±40°, the dimensional stability after thermal cycling will be insufficient, and if the composition of the inner and outer layers is reversed, many cracks will occur in the deformed product. occurs, so as in the present invention, the winding angle hC
Inner layer from ±40° to ±90' and winding angle from ±20" to ±3
It is necessary to construct it from the outer layer of 0°.

In the present invention, the reinforcing m-fiber is carbon tIN, which is limited to this material in view of its high specific elasticity and high specific strength. It goes without saying that higher rigidity can be obtained by using high modulus carbon fibers, and it is even more effective to use carbon fibers with different elastic modulus and strength, if necessary.

The fiber-reinforced 71-lix resins include epoxy resins, phenolic resins, bismaleimide resins, and the like.

The carbon IIN reinforced resin pipe of the present invention can be easily obtained by a normal 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 explained with reference to the drawings.

As shown in Fig. 1, the winding angle is set between ±40” and ±90° in order to obtain dimensional stability between the straight line on the outer peripheral surface of the pipe parallel to the axis of the pipe and the direction of the reinforcing fibers after cycle loading. As shown in Fig. 2, the outer layer has a winding angle of ±20° to ±301° to increase strength and rigidity, and its outer surface is This piston pin is characterized in that it is made of a material that has higher hardness than carbon fiber reinforced resin, mainly to improve impulse characteristics.

[Examples and comparative examples]

Example 1 A piston pin was manufactured by the filament winding method as described below. That is, a core metal with a diameter of 7.5 mm was made of $11ffl of carbon pre-impregnated with epoxy resin (Besphite oHT A-7-6000 manufactured by Toho Rayon Co., Ltd.).
) was rolled around. The winding angle at this time is as shown in FIG. The sign of the winding angle θ is positive in the counterclockwise direction. The wire was wound so that the winding angle θ was ±70° and the outer diameter was φ14III.
The winding angle θ should be ±20°, and the outer diameter should be φ2.
It was wound until it became 1 mm. After heating and curing, the mold was demolded, and then polished to form a hard chrome plating layer on the outer surface of the pipe.
I changed it to @. Then, this was cut into a length of 70 mm to form the piston pin shown in Fig. 2 (q). 3 shows a layer composed of reinforcing fibers with a winding angle θ of ±20°, and 3 shows a hard chrome plating layer forming the outer surface layer of the carbon fiber reinforced resin pipe.

Example 2 Using the same method as in Example 1, a carbon wire N (Besphite O manufactured by Toho Rayon Co., Ltd. - ITA7-6000) impregnated with epoxy resin was prepared so that the winding angle θ was ±10°. After winding until it becomes φ14mm, the winding angle θ
so that the angle is ±20°, and the outer diameter is φ2111IW.
Carbon ieiM pre-impregnated with epoxy resin until
(Bess 7 foot made by Toho Rayon Co., Ltd. @HMS-40-60
00> Wind it up.

The subsequent operation is the same as in Example 1, and the piston pin is
It was.

Comparative Example 1 was molded and the erosion operation was carried out in the same manner as in Example 1 to obtain a piston pin.

Comparative Example 2 Using the same method as Comparative Example 1, the winding angle θ of the reinforcing fibers was changed to Oo,
±10°, ±30', ±40°, ±50°±70°, ±
A pipe with a 90° angle is formed, and the subsequent operations are as in Example 1.
A piston pin was obtained in the same manner.

Measurement and Evaluation of Properties The piston pin obtained as described above was evaluated for its bending properties, which are closely related to the winding angle of the reinforcing fibers, and its dimensional stability after thermal cycling. First, by the method shown in Figure 3,
By conducting a bending test, the strength of the piston pin,
Rigidity was evaluated. The measurement results are shown in FIGS. 4 and 5. The strength is high when the winding angle θ of the reinforcing fibers, which has a large bending breaking load, is ±20° to ±50°, and the rigidity is large when the winding angle θ of the reinforcing fiber is ±20° to ±50°, which has a large bending failure load. It is high when

Therefore, in order to increase strength and rigidity, ±20' to ±3
It can be seen that it is necessary to orient the reinforcing fibers in the range of
The change in the outer diameter of the pipe over time was investigated. In addition, the size measurement shows that the fruit is grown at room temperature. The piston pin according to the invention is excellent in all properties.

Table 1 Changes are small. However, these have low strength and rigidity as mentioned above, and are not suitable for piston pins.

That is, from the results shown in FIGS. 4 to 6, in carbon fiber reinforced resin pipes like the piston pins of the present invention shown in Examples 1 and 2, the winding angle θ of the reinforced IIM is ± The pipe is composed of an inner layer with a winding angle θ of 40" to ±90" and a layer with a reinforcing fiber winding angle θ of ±20" to ±6306, and the outer surface of the pipe is made of a material with higher hardness than the fiber-reinforced resin. It has been demonstrated that the configuration is most suitable for piston pins.

〔Effect of the invention〕

The relationship between each lfj piston pin and each characteristic explained above is as follows:
They are summarized in Table 1. In the table, the O mark indicates that the property is excellent, and the X mark indicates that the property is poor.

[Brief explanation of the drawing]

FIG. 1 shows the winding angle θ of the reinforcing fiber according to the present invention. FIG. 2 shows an example of the piston pin of the present invention. In the figure, 1 is a layer in which the carbon fiber winding angle is ±70°, and 2 is a layer in which the carbon fiber winding angle is ±20°.
The layer 3 shown in FIG. 1 is a hard chrome plating layer that constitutes the outer surface layer of the carbon fiber-reinforced resin pipe. Figure 3 is a bending test to evaluate the strength and rigidity of the piston pin! This is a schematic diagram of the installation. 4 in the figure indicates the specimen. FIG. 4 shows the breaking load for each piston pin as a result of a bending test conducted using the method shown in FIG. 3. In the figure, ±20°/±70° (1) indicates that obtained in Example 1, and ±20°/±70° (2) indicates that obtained in Example 2. Figure 5 shows the unit bending deflection length (1 mm) of each piston pin as a result of the bending test performed using the method shown in Figure 3.
) shows the load against. Similarly to Figure 4, in the figure, the values of ±20°/±10° (1) are those obtained in Example 1, and the values of ±20°/±70° (2) are those obtained in Example 2. It shows what was done. FIG. 6 shows the relationship between the holding time of each piston pin at high temperature (180° C.) and the change in the outer diameter of the bottle. Figures 4 and 5
Similarly to the figure, in the figure, ±20°C/±70°C (1) was obtained in Example 1, and ±20°C/±10°C (2) was obtained in Example 2. showing something. Figure 6 E3 soft (8)

Claims (1)

[Claims] In a pipe composed of a pipe body and an outer surface layer, the pipe body is made of carbon fiber reinforced resin and has an inner layer with a winding angle of ±40° to ±90° and a winding angle of ±20° to ±3.
1. A piston pin characterized in that the pipe outer surface layer is made of a material having a higher hardness than the carbon fiber reinforced resin.