JP3008186B2 - Connecting rod and method for manufacturing connecting rod - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connecting rod for an internal combustion engine in which a large end of a connecting rod to be formed by forging is split and broken, and a method for manufacturing the connecting rod.

[0002]

2. Description of the Related Art A connecting rod consisting of a large end, a small end and a rod portion connecting them is formed by forging, and a groove is formed at a portion to be split at the large end in the middle of mechanical finishing. Japanese Patent Laid-Open No. Sho 5
8-37311, JP-A-61-21414, and JP-B-3-18053.

[0003]

The above-mentioned conventional grooving is a mechanical process, and a special tool such as a broach is used because a sharp shape is required. Further, there is a problem that the edge of the fractured surface is rough and easily chipped off. Groove processing for breaking and dividing the large end is more effective as the notch function is larger and deeper, but on the other hand, the fracture split surface is used for joining. There is a contradiction in that, when the notch is made deeper and deeper, contradiction arises such that the joining area becomes smaller, and there is a limit to making the notch larger and deeper.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the need for machining of a notch, improve the fracture splitting performance of the large end by making the notch deeper, and increase the joint area of the fracture splitting surface to increase the resistance to lateral displacement. An object of the present invention is to provide a connecting rod and a method for manufacturing the connecting rod.

[0005]

According to a first aspect of the present invention, there is provided a connecting rod comprising a large end, a small end, and a rod connecting the two ends. In the process of forming a notch on the end face and / or side face of the fracture splitting scheduled portion of the large end ,
The notch is forged from both sides to leave a forged defect as a notch, and the notch is split at the notch.

According to a second aspect of the present invention, there is provided a method for manufacturing a connecting rod according to the present invention, in which a connecting rod comprising a large end, a small end, and a rod connecting between the two ends is formed by forging. In the rough forging stage, V-shaped or U-shaped
A groove having a shape is formed, and in the deburring forging step, the groove is forged from both sides to leave a forging defect as a notch.

According to a third aspect of the present invention, in the process of forging a connecting rod consisting of a large end, a small end and a rod connecting between the large end and the small end, the large end is formed in a deburring forging stage. A V-shaped or U-shaped groove is formed on the end face and / or the side face of the portion to be fracture-divided, and then the groove is forged from both sides to leave a forging defect as a notch. is there.

In another manufacturing method, the notch shape of the end face is a sawtooth shape and a lightning shape ,
It is characterized in that the lateral displacement resistance of the joint surface is enhanced.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2, reference numeral 1 denotes a connecting rod according to the present invention, which comprises a large end 2, a small end 3, and a rod 4 connecting the ends, and is formed by forging.

In the connecting rod 1 according to the present invention, a forging defect is left as a notch 5 in advance at a portion of the large end 2 where the fracture is to be divided, and the notch 5 is divided at the notch 5.

The manufacturing method of the present invention for manufacturing the connecting rod 1 will be described with reference to FIGS. First Embodiment In a first embodiment, as shown in FIG. 3, a connecting rod 1 of the present invention is manufactured in which the forging defect is left as a notch 5 in the forging process of (a) to (f).

That is, FIG. 3A shows a round bar 10 which is a material, and FIG. 3B shows a state 11 in which meat is distributed by a reduce roll. 3 (c) to 3 (e) show a forming process in a generally used mechanical press for forging, and FIG. 3 (c) shows a state 11 in which the distribution of meat after the above-described reduce roll forging is performed. The crushed flat form 12 is used, and FIG.
Then, the crushed flat shape 12 is roughly forged into a shape close to the shape of the connecting rod 1. Further, in FIG. 3 (e), forging is performed to leave the burr 13 in the finished shape. And
Finally, the burr 13 generated in the roughing stage by another press
Is removed to obtain a product of the connecting rod 1 as shown in FIG.

Therefore, in the first embodiment of the present invention, in the rough forging step shown in FIG. 3D, at the same time, a forging defect, which will be described later, is formed on the end face and / or the side face of the portion of the large end 2 to be divided. A V-shaped or U-shaped groove 5a to be left as the notch 5 is formed. The notch on the end face is desirably formed in a sawtooth shape and a lightning bolt shape .

Further, in the deburring forging step in FIG. 3E, the large end 2 and the small end 3 of the connecting rod 1 are formed.
The groove 5a is forged from both sides by applying a forging force to the groove 5a, and the expanding V-shaped or U-shaped groove 5a is pressed to leave a forging defect as a notch 5. V type or U
Although the press-fitting of the groove 5a of the shape is intimately contacted by the forging force, it is not joined at all, and the forging ends with a wrinkle scratch state corresponding to a defect in a general forged product. Finally, as described above, the burr 13 generated in the roughing stage is removed by another press to obtain a product of the connecting rod 1 as shown in FIG.

That is, in the rough forging step shown in FIG. 3D, as shown in FIG. 4, a V-shaped or U-shaped groove is formed on the end face and / or the side face of the portion of the large end 2 where the fracture is to be divided. In the deburring and forging step shown in FIG. 3E, the V-shaped or U-shaped groove 5a which has been expanded becomes a wrinkle-shaped forging defect and becomes a notch 5a. It remains as. Moreover, since the notch 5 forges the V-shaped or U-shaped groove 5a that has been expanded, deep wrinkles can be obtained as shown in FIG.

The forged product of the connecting rod 1 which has been subjected to the deburring and forging step in FIG. 3 (e) is thereafter machined through heat treatment, shot blasting and the like, if necessary, and during or after the machining. Breaking and splitting are performed at the portions to be broken and split by the notch 5.

In the above-mentioned fracture splitting, the notch 5 formed by the wrinkle scar formed at the time of forging is deeper and sharper than the groove formed by the conventional machining, so that the fracture dividing work can be easily obtained, and at the time of joining use. Since the notch 5 is also included in the fracture split surface, the joining area is large, and a strong resistance to lateral displacement is obtained. The resistance to the lateral displacement can be obtained even more strongly by forming the shape of the notch 5 on the end face into a sawtooth shape and a lightning bolt shape .

[Second Embodiment] The second embodiment is the same as the technical idea of the first embodiment, except that the formation of the V-shaped or U-shaped groove 5a and the process of forging and forging the groove 5a are changed. .

That is, as shown in FIG.
The forging process of (e) is the same as in the first embodiment. First
In the embodiment, the V-shaped or U-shaped groove 5 is used in the rough forging step (d).
In the second embodiment, as shown in (f) of FIG. 7, in the deburring forging step, a portion of the large end portion 2 where the fracture is to be split is formed. End face and / or
Alternatively, a V-shaped or U-shaped groove 5a is formed on the side surface, and as shown in FIG. The groove 5a is forged and the expanded V-shaped or U-shaped groove 5a is pressed to leave a forging defect as a notch 5. Also in this case, it is desirable that the notch on the end face is formed in a sawtooth shape and a lightning bolt shape .

In this second embodiment, as in the first embodiment, the V-shaped or U-shaped groove 5a is tightly pressed by the forging force P, but is not joined by any means. Forging is finished in the state of wrinkles corresponding to the defect in the above, and the notch 5 due to the wrinkles formed at the time of forging is deeper and sharper than a groove formed by conventional machining,
The fracture splitting operation can be easily performed, and the notch 5 is also included in the fracture division surface when the joint is used, so that the joining area is large and the resistance to the lateral displacement is strongly obtained. The resistance to the lateral displacement is determined by changing the shape of the notch 5 on the end face into a sawtooth shape and a rice.
By forming it in a wife shape , it can be obtained even more strongly.

[0021]

As described above, according to the present invention, a V-shaped or U-shaped groove is formed at a portion where a large end is to be fractured and split at the forging stage, and the V-shaped or U-shaped groove is forged by forging and pressed to reduce forging defects. Since the notch is left as a notch, the notch is deep and sharp, the break division property is improved, the break operation is facilitated, and the break section can be divided without being chipped off. In addition, when joining is used, notches that have been forged due to crimping are included in the fracture split surface, so the joint area is large, resistance to lateral displacement is obtained strongly, and the strength of the large end is improved. Has the advantage that it can be provided.

[Brief description of the drawings]

FIG. 1 is a front view of a connecting rod according to the present invention.

FIG. 2 is a side view of FIG. 1;

FIG. 3 is a diagram showing a first embodiment of the manufacturing method according to the present invention.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is a sectional view taken along line BB of FIG. 3;

6 is a sectional view taken along line CC of FIG. 3;

FIG. 7 is a diagram showing a second embodiment of the manufacturing method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Connecting rod 2 Large end 3 Small end 4 Rod 5 Notch 5a V-shaped or U-shaped groove

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16C 7/02 B21K 3/00 B26F 3/00

Claims (4)

(57) [Claims] In the process of forging a connecting rod composed of a large end, a small end and a rod part connecting between the large end and a small end, an end face and / or a side of a part of the large end to be split.
Form a notch on the surface and forge this notch from both sides
A connecting rod, wherein a forging defect is left as a notch, and the notch is split at the notch. 2. In the process of forging a connecting rod consisting of a large end, a small end and a rod part connecting between the large end, a V end on the end face and / or the side face of the part to be fracture-divided at the large end in the rough forging stage. 2. The method according to claim 1, wherein a groove having a U-shape or a U-shape is formed, and the groove is forged from both sides in a finish forging step so that a forging defect is left as a notch. 3. A process for forging a connecting rod consisting of a large end, a small end and a rod part connecting the small end with a V end on the end face and / or the side face of the part to be fracture-divided at the large end in the deburring forging step. 2. The method according to claim 1, wherein a groove having a U-shape or a U-shape is formed, and then the groove is forged from both sides to leave a forging defect as a notch. 4. The end face has a notch shape having a sawtooth shape and a lightning bolt.
4. The method for manufacturing a connecting rod according to claim 2, wherein the connecting rod has a shape so as to enhance the lateral displacement resistance of the joint surface.