JPS6313044B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a connecting rod for an internal combustion engine.

In recent years, internal combustion engines have been operating at increasingly high speeds, and with this high speed operation, there has been a need to reduce the weight of reciprocating parts such as connecting rods in order to reduce vibration and noise. There is. Recently, for this purpose, lightweight materials such as aluminum alloys and magnesium alloys have been used in place of conventional steel to reduce weight. However, this type of lightweight material has lower strength than steel, and the strength decreases even more at high temperatures, so the wall thickness must be increased.
There was a drawback that it was not necessarily possible to reduce the weight by the difference in specific gravity.

In view of the above points, the present invention has been made with the aim of reducing the weight of such connecting rod materials by reinforcing them with reinforcing fibers. By skillfully arranging the connecting rod to effectively support the load caused by the explosive force and inertial force of the connecting rod, it was possible to further increase the strength of the connecting rod and make it even lighter.

Hereinafter, the structure of the present invention will be explained based on drawings showing one embodiment. FIGS. 1 and 2 show an example of a connecting rod obtained by the present invention, and in the figures, 1 is A portion of the stem 4 connecting the small end 2 and the large end 3 constitutes an inner wall portion of the stem 4,
and a stem column made of fiber-reinforced composite material;
5 is the outer flesh on both left and right sides of the stem 4 and the small end 2
The thin stem plates 6a, 6b, and 6c, which constitute the fiber-reinforced composite material, are the remaining members disposed in the remaining portions of the small end 2 and the large end 3. Further, 7 constitutes a remaining member of the cap 8 divided from the main body of the large end portion 3, 9 constitutes a part of the cap 8 disposed on the lower end surface of the remaining member 7,
The cap plate 10 made of fiber-reinforced composite material is a tightening bolt for attaching the cap 8 to the main body of the large end 3.

In the above, the stem column 1 made of fiber-reinforced composite material has a rod shape with a rectangular cross section as shown in FIG.
In order to fit into the piston pin hole 11 in the figure, it is formed into a semicircular concave portion 12 having the same radius of curvature as the radius R _S of the piston pin hole 11, and the other end is fitted into the crank pin hole 13 of the large end portion 3. To match, it is formed in a similar recess 14 having the same radius of curvature as the radius R _B of the crank pin hole 13 .

By the way, as mentioned above, this stem column 1
is arranged on the inner wall of the stem 4 extending from the small end 2 to the large end 3, and the explosive force of the engine mainly acts on this part. Therefore, in the present invention, the fibers reinforcing the stem column 1 are arranged so as to receive the compressive load due to the explosive force, that is, arranged in that direction, thereby effectively securing the strength against the compressive load. . Such reinforcing fibers include glass, carbon, silicon carbide, etc., and their base materials include light alloy materials such as Al or Mg, and plastic materials such as epoxy resin, but other materials may also be used. But that's fine. here,
Assuming that the compressive load due to explosive force is Wp and the allowable compressive stress of the column 1 material is σc, the dimensions a and b of column 1 shown in FIG. 3 are determined by the following equation.

Wp/ab < σc However, a=2R _S In addition to the above-mentioned fiber arrangement in one direction, in order to maintain transverse strain strength against compressive load, fibers are arranged in a direction perpendicular to or diagonally to the direction of the compressive load. Fibers may also be included.

As shown in FIG. 4, the stem plate 5 is in the form of a thin plate, and the center portion thereof is bent into a semicircle 15 to form the small end portion 2, thereby forming the whole into a substantially U-shape. . In this case, the inner radius of the central bent portion 15 is the same as the radius R _S of the piston pin hole 11. On the other hand, both ends 1 of the stem plate 5 extend toward the large end 3 while forming both outer surfaces of the stem 4.
6 and 16 are bent outward. The both end portions 16, 16 constitute a part of the large end portion 3, but in this embodiment, the both end portions 16, 16
As shown in FIG. It is held in a sandwiched state with another remaining member 6b constituting the section, increasing the joint strength against tension. That is, it is also possible to arrange the both ends 16, 16 on the upper surface of the shoulder of the large end 3. In this case, the both ends 16,
16 is temporarily held down by the head of the tightening bolt 10 of the cap 8, but when a tensile load is applied upward due to the reciprocating inertia force, both ends 16, 16 separate and fall upward. In this way, the remaining member 6
By arranging it below c, such detachment can be prevented and it can be firmly held. Therefore, these end portions 16, 16 may be arranged so as to be exposed on the joint surface with the cap 8 as shown by the two-dot chain line in FIG. 1, but in this case, the inner surface of the stem plate 5 It is desirable to prevent it from being exposed to the hole 13 side. In addition, other remaining members 6a,
6a constitutes the front and back corners of the stem column 1 in the lower half of the piston pin hole 11 and the front and back corners of the stem column 1 above the crank pin hole 13. However, the remaining members 6a, 6a on the side of the crank pin hole 13
is continuous with the remaining member 6b at the junction with the cap 8 at the large end 3. Furthermore, the remaining members 6b, 6c
may be made continuous with each other in order to strengthen the holding force of the two ends 16, 16.

In addition, if both ends 16, 16 of the stem plate 5 are curved upward to have an upward angle θ, as shown by two-dot chain lines in FIGS. The holding force of 16, 16 is further increased.

As described above, this stem plate 5 constitutes the small end portion 2, the outer wall portion of the stem 4, and the large end portion 3, and the tensile load mainly due to the inertial force of the piston etc. acts on these parts. Now, the reinforcing fibers of the stem plate 5 are arranged in a direction that receives such a tensile load, thereby ensuring effective strength against the tensile load. The reinforcing fibers and matrix material in this case are the same as in the case of the stem column 1.
Here, assuming that the tensile load due to inertial force is W _I and the allowable tensile stress of the compound reinforced stem plate 5 is σt, the width and thicknesses B and T of the stem plate 5 in FIG. determined.

W _I /2B・T<σt Note that, as in the case of stem column 1, the reinforcing fibers are basically arranged in one direction so as to receive tensile load, but the strength against transverse strain is maintained. Where necessary, fibers in the right angle or diagonal direction may be additionally included.

As shown in the figure, the stem plate 5 and the stem column 1 are widened or widened at the large end 3 side, but the upper and lower sides may have the same width.

Next, as shown in FIG. 5, the cap plate 9 is in the shape of a thin plate, and has a concave shape in the center to fit the shape of the lower surface of the remaining member 7 of the cap 8.
Its both ends are made flat to serve as the seat surface 17 of the tightening bolt 10, and the reinforcing fibers are arranged in one direction in the direction of the bending stress of the cap 8 due to inertial force, thereby providing strength against inertial force loads. This provides rigidity and strengthens the tightening bolt 10 seating surface 17. In this case, the fibers and matrix are:
This is the same as in the case of stem column 1. However, this cap plate 9 may be omitted depending on the case.

During manufacturing, the stem column 1, stem plate 5, and cap plate 9 made of the fiber composite reinforced material are preformed into a predetermined shape, set in a mold for forming a connecting rod, and the remaining material is placed on top of the stem column 1, stem plate 5, and cap plate 9. A finished product can be obtained by pressurizing and injecting the matrix material constituting the members 6a, 6b, 6c, and 7, which also serves as the adhesive for the members 1, 5, and 9. In addition, in this embodiment, the remaining members 6, 7
are the upper and lower surfaces of the stem column 1 at the lower part of the piston pin hole 11, and the crank pin hole 1 at the big end 3.
3, both the left and right sides, the upper and lower surfaces of the stem column 1, and most of the area around the crank pin hole 13 in the connecting rod cap 8, and the remaining members 6 and 7 also contain short, randomly arranged reinforcing fibers. It is also possible to create a similar complex.

Note that the width of the small end 2 side of the stem plate 5 and stem column 1 in FIGS. 3 and 4 is the same as the other widths, but in the embodiment shown in FIG. It has a tapered shape that becomes narrower toward the tip, and the tip side that receives the inertial force of the piston is made thick enough to receive the inertial force, resulting in a lighter structure. Further, a metal for receiving the pin may be fitted into the piston pin hole 11.

The present invention is as described above, and thus, in the present invention, at least the connecting rod stem portion is formed by a fiber-reinforced stem column and a stem plate, and these fiber arrangements are respectively exploded. Since it is configured to effectively receive compressive loads due to force and tensile loads due to inertia, it has high strength against these loads, and is therefore lighter than conventional ones by making the stem part smaller in size. It was possible to do so. In particular, according to the present invention, since the end of the stem plate that receives a tensile load is placed and supported under pressure on the large end upper surface member, which is another member, the end of the stem plate that receives a tensile load is This has the effect of preventing the stem plate from coming off.

[Brief explanation of the drawing]

Fig. 1 is a front view of the connecting rod according to the invention, Fig. 2 is a side view of the connecting rod of the present invention, Fig. 3 is a perspective view of the stem column, Fig. 4 is a perspective view of the stem plate, and Fig. 5 is the cap. It is a perspective view of a plate. 1... Stem column, 2... Small end, 3... Large end,
4...Stem, 5...Stem plate, 16...Stem plate end, 6c...Remaining member (large end upper surface member).

Claims (1)

[Claims] 1 At the stem part connecting the large end and small end of the connecting rod,
It has an inner stem column and an outer stem plate made of at least a fiber-reinforced composite material, the stem column having fibers arranged so as to mainly support the compressive load during an explosion, and the stem plate mainly having tensile inertia. The fibers are arranged so as to support the force, and the end of the stem plate extending toward the large end of the connecting rod is placed below the large end upper surface member constituted by other members. A connecting rod for an internal combustion engine characterized by: