JPH0225932Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field The present invention relates to a connecting rod made of fiber-reinforced plastic used in internal combustion engines, etc., and more specifically, to reinforce the plastic base and improve its wear resistance. This invention relates to a connecting rod made of fiber-reinforced plastic with improved rigidity.

BACKGROUND TECHNOLOGY AND PROBLEMS As shown in FIGS. 1A and 1B, a connecting rod (hereinafter simply referred to as a connecting rod) 1 of an internal combustion engine, etc., has a small end portion 1a that is connected to a connecting rod via a piston pin 2. connected to the piston 3,
It is connected to the crankshaft 4 at the large end 1b. The explosion pressure within the combustion chamber, including the top surface of the piston, is received from the piston 3 and transmitted to the crankshaft 4. Therefore, a large compressive stress due to the explosion pressure from the piston 3 is applied to the connecting rod 1, and at the same time, a tensile stress due to inertial force is also applied to the connecting rod 1. Therefore, the connecting rod 1 is generally manufactured by die forging carbon steel. However, if it is made of steel, it naturally has a high specific gravity, which increases the inertial force during operation, which causes problems such as increased engine vibration.

Furthermore, since the connecting rod 1 is in sliding contact with the crankshaft 4 and the piston pin 2, it is likely to wear out. For this reason, special gold bearings are generally used for this sliding part, but this poses a problem in that it requires a lot of assembly man-hours and becomes complicated.

In view of this situation, the use of stove rods made of fiber-reinforced plastics has recently attracted attention. This fiber-reinforced plastic cooking stove has strong, hard, and self-lubricating carbon fibers arranged within the plastic base.This makes it lightweight, strong enough, and has excellent lubricity. Good stoves began to be made. However, in this plastic conrod, the base is made of relatively soft plastic, especially on the sliding contact surface on the inner surface of the conrod 1, so this part is selected as shown in FIG. 2 due to the high speed sliding contact with the high surface pressure. be worn out or deformed. As a result of the carbon fibers 5 protruding, the surfaces of the piston pin 2 and crankshaft 4 of the other party may be damaged, or cracks 7 may occur from the plastic base 6 which is dented due to wear or deformation, or even if the wear or deformation is slight. There were problems such as cracks occurring from the plastic base 6 due to repeated stress, and because the base 6 was made of plastic, the overall rigidity of the cooking stove was insufficient.

Purpose of the invention The present invention was made to eliminate the above-mentioned problems.The purpose was to improve the wear resistance of the parts of the conrod that come in direct sliding contact with the crankshaft and piston pin, and to improve the wear resistance of the parts of the conrod that come into direct sliding contact with the crankshaft and piston pin. To provide a connecting rod made of fiber-reinforced plastic that is not subject to excessive wear or deformation, has high rigidity, and is strong in strength.

Summary of the invention In order to achieve the above-mentioned object, the present invention is a connecting rod in which a plastic base is reinforced with carbon fibers and further reinforced with short whisker fibers, and the connecting rods are connected to each other in the longitudinal direction. A layered carbon fiber body is formed into an almost connecting rod shape by laminating strips formed by assembling carbon fibers in a lattice shape, and this layered carbon fiber body having an almost connecting rod shape is impregnated. a plastic base that has been cured by drying, in which short whisker fibers that have been included in the plastic base prior to the impregnation are dispersed, and the strip of the layered carbon fiber body is The laminated carbon fibers are laminated and wound so that the pair of pin holes are formed between the pair of pin holes provided at both ends of the bearing rod, and thereby the layered carbon fiber body is almost connected. This invention relates to a connecting rod characterized in that it is configured in the shape of a connecting rod.

By configuring as described above, the wear resistance of the parts that come into direct sliding contact with the crankshaft and piston pin of the conrod is improved, and unlike in the past, only the plastic base does not wear excessively, making it lightweight and rigid. To provide a cooking rod made of fiber-reinforced plastic that is high in size, strong in strength, and easy to manufacture.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 3A to 8.

First, as shown in FIG. 3A, the carbon fiber 10 is
A strip of a predetermined width and a predetermined length is assembled in a lattice shape at a substantially constant angle (approximately 45 degrees) to the longitudinal direction of the strip to be formed and intersects with each other.
Make 1. This strip-shaped body 11 is processed to form a strip-shaped body 12 having a predetermined shape as shown in FIG. 3B. This strip-shaped body 12 is then wound around a molding core 13, as shown in FIG. This molding core 13 is provided with pins 14 and 15 corresponding to the respective sizes at positions corresponding to the piston pin and crankshaft. , 15, a layered carbon fiber body 16 made of the required number of layers of carbon fibers is formed. Next, as shown in FIG. 5, this layered carbon fiber body 16 is sandwiched between split outer molds 17, arranged into a predetermined shape, and fixed. Then, a preimide resin containing short fibers of silicon carbide whiskers is infiltrated into the layered carbon fiber body 16, preferably under pressure, and heated and hardened to form a connecting rod 18 in a nearly completed shape (FIG. 6). The pin holes and the like of the connecting rod 18 thus formed are then machined into a predetermined shape. The reason why the carbon fibers 10 are formed in a lattice shape by crossing each other is to minimize the directionality (anisotropy) of the mechanical properties of the carbon fibers 10. Although the connecting rod 18 in the above embodiment has an integral structure, by changing the shape of the outer mold 17, the molding core 13 can be molded into a split-shaped connecting rod as shown in FIG. 1B. In this case, one pin hole becomes a half hole.

In addition to the above-mentioned silicon carbide, silicon nitride may be used as the whisker, and the elastic modulus of these materials is approximately 50000 Kg/mm ² .
The maximum tensile strength is about 1400Kg/ ^mm2 . In addition to the polyimide resins mentioned above, polyamide resins and epoxy resins are also suitable as base plastics, which not only greatly contribute to weight reduction but also have a certain degree of heat resistance strength. Carbon fiber has an elastic modulus of approximately 25000Kg/mm ² and a tensile strength of
It is about 210-300Kg/ ^mm2 . The volume filling rate of the reinforcing fibers is preferably approximately 20 to 60% carbon fiber and 5 to 20% whisker. In this example, carbon fiber is approximately 30% and silicon carbide whisker is approximately 15%. % filled.

FIG. 7 schematically shows the surface of the connecting rod 18 made of fiber-reinforced plastic made in this way, as viewed through a microscope. According to this, the plastic base 19 is a grid-like carbon fiber 1
0 and silicon carbide whiskers 2 distributed between these lattices.
It can be seen that the material is doubly reinforced by the 0 short fibers.

The cooking stove according to the present invention consists of a layered carbon fiber body formed in the shape of a cooking stove by laminating strips of carbon fibers arranged in a lattice so as to intersect with each other in the longitudinal direction, and a layered carbon fiber body formed almost in the shape of a cooking stove. It consists of a plastic base made by impregnating and hardening a layered carbon fiber body in the form of a woven rod, and whiskers dispersed in the plastic base.

Therefore, the plastic base on the sliding surface of the cooking stove is reinforced by the strong and hard carbon fibers in the form of a lattice, and the even stronger and harder short whisker fibers distributed between the lattices. The contact surface has become stronger and more rigid, so even if it is subjected to high speed friction force with high contact pressure,
It can sufficiently withstand compressive stress and deformation caused by this surface pressure, wear caused by frictional force, and the like. As a result, only the plastic base is prevented from being excessively worn or deformed and dented, and cracks do not occur from the dents. Furthermore, even if the compressive stress is repeated, no cracks will occur.

In addition, the compressive stress and tensile stress in the longitudinal direction of the connecting rod are similarly shared by the strong and hard carbon fibers and the even stronger and harder whiskers distributed between the lattices. Since the carbon fibers are arranged in a lattice pattern so as to intersect with each other in the longitudinal direction, the directionality of the mechanical properties of the carbon fibers can be reduced as much as possible, making the connecting rods even stronger than conventional ones. It becomes physically strong and highly rigid.

In addition, lubrication on the sliding surfaces of the connecting rod is mainly carried out by the self-lubricating carbon fibers that are in contact with each other through a lubricant, but the relatively soft plastic base is appropriately dented. This recess will always hold the lubricant,
Lubricity will also be improved.

Furthermore, the layered carbon fiber strip is laminated and wound so that the pair of pin holes are formed between the pair of pin holes provided at both ends of the connecting rod, As a result, the layered carbon fiber body is constructed approximately in the shape of a connecting rod. Therefore, the layered carbon fiber body in the shape of a connecting rod is simply impregnated with a plastic base in which short whisker fibers are dispersed and then cured. Since these are present in a laminated state along the inner circumferential surface of the pin hole, the strength and rigidity of the sliding surface are further increased, and the lubricity is further improved.

[Brief explanation of the drawing]

Figures 1A and 1B are diagrams showing the relationship between the piston, connecting rod, and crankshaft. Figure 1A is a vertical cross-sectional view taken along a plane parallel to the piston pin, and Figure 1B is a vertical cross-section taken along a right-angled plane. FIG. 2 is an enlarged cutaway perspective view of the defective sliding surface in the conventional example, and FIGS. 3A to 8 show an embodiment of the connecting rod according to the present invention. 3B and 3B are perspective views of carbon fiber strips arranged in a lattice pattern, FIG. 4 is a perspective view showing the process of winding the carbon fiber strips around a core, and FIG. Fig. 6 is a perspective view of the molded conrod surface, Fig. 7 is a schematic diagram of the conrod surface seen under a microscope, and Fig. 8 is a diagram of the sliding surface of the conrod. FIG. 2 is an enlarged perspective cutaway view similar to FIG. 2; In addition, in the symbols used in the drawings, 1...connecting rod, 10...carbon fiber, 11,
12... Band-shaped body, 16... Layered carbon fiber body, 18
...Conrod, 19...Plastic base,
20...Whisker.

Claims (1)

[Claim for Utility Model Registration] A connecting rod in which a plastic base is reinforced with carbon fibers and further reinforced with short whisker fibers, and the carbon fibers are lattice so as to intersect with each other in the longitudinal direction. A layered carbon fiber body formed into an almost connecting rod shape by laminating strips formed in a shape, and a plastic base impregnated into the layered carbon fiber body having an almost connecting rod shape and hardened. and the plastic base is dispersed with short whisker fibers that were included in the plastic base prior to the impregnation, and the strip of the layered carbon fiber body is arranged at each end of the connecting rod. The layered carbon fiber body is laminated and wound so that the pair of pin holes are formed between the pair of provided pin holes, and thereby the layered carbon fiber body is formed into a substantially connecting rod shape. A connecting rod characterized by: