JP3012510B2 - Method and apparatus for dividing connecting rod cap in forged 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 method for manufacturing a connecting rod, and more particularly to a method for manufacturing a connecting rod manufactured by forging a steel material by performing broaching on an inner peripheral surface of a large end and dividing a connecting rod cap using the same jig. The present invention relates to a method and an apparatus for dividing a connecting rod cap in a forged connecting rod to be formed.

[0002]

2. Description of the Related Art Conventionally, forged connecting rods used in internal combustion engines, a method of individually manufacturing a connecting rod body and a cap of the connecting rod and a method of integrally manufacturing both the connecting rod body and the connecting rod cap from the beginning. There is. In this integrated manufacturing method, the connecting rod body and the connecting rod cap are divided by machining.

[0003]

In the above-mentioned conventional method for manufacturing a connecting rod, the method for manufacturing by cutting a connecting rod cap integrally forged with the large end of the connecting rod body requires a lot of cutting steps. In order to improve this method, a method has been proposed in which a connecting rod cap is integrally forged at the large end, and then a split collar is inserted into a bearing hole at the large end, and a wedge is driven between the split collars to split into two. . For example, there is one disclosed in JP-A-58-37311. However, the split collar (jig) used in this method has a tapered shape, and a wedge is pressed into the split collar to forcibly split the large end of the connecting rod body. For this reason, in order to set the division position of the large end to a predetermined fixed position, before inserting the division collar (jig) into the large end, broaching is performed at the division position where stress at the time of division is concentrated on the large end. It is carried out. Therefore, there is a problem that a broaching process is required before the dividing process using the jig. The present invention
Solving the problems of the conventional forged connecting rod described above, without the need for the broaching step before the dividing step by the jig, the connecting rod cap in the forged connecting rod that can be simultaneously and accurately divided following the broaching. It is an object of the present invention to provide a dividing method and an apparatus therefor.

[0004]

In order to achieve the above object, a method of dividing a connecting rod cap in a forged connecting rod according to the present invention is to split a connecting rod cap by inserting a jig into a large end of a connecting rod manufactured by forging. In the molding method, the jig to be inserted into the large end of the connecting rod is composed of a split mold and a broach part, and broach processing is performed in advance at the time of division at the broach part protruding from the lower end of the split mold, followed by The connecting rod cap is divided and molded from the front broach groove by a split mold that descends.

The method for dividing the connecting rod cap in the forged connecting rod of the present invention having the above-mentioned structure makes the manufacturing process simple because broaching is performed on the inner peripheral surface of the large end portion of the connecting rod and the division can be performed in the same jig in one step. In addition, division can be performed with high accuracy by broaching just before division.

Further, the connecting rod cap dividing device for a forged connecting rod according to the present invention comprises a jig for forming a connecting rod cap by dividing the large end of the connecting rod, a broach part having a broach blade at a lower end, and a taper at an upper part thereof. A split mold is continuously formed through the surface, and the jig is strongly pressed into the large end of the connecting rod so that the splitting is performed simultaneously with the broaching.

The connecting rod cap dividing device for a forged connecting rod according to the present invention having the above-mentioned structure is provided with a jig for forming a connecting rod cap which is divided from a large end of the connecting rod via a broach portion provided with a broach blade and a tapered surface. The jig is simple and the broaching and splitting can be performed simultaneously.

Further, the connecting rod cap dividing device for a forged connecting rod according to the present invention provides a jig for forming a connecting rod cap by dividing the large end of the connecting rod into a broaching section provided with a broach blade and having a smaller diameter than the broaching section main body. A tapered shaft portion that is thicker from the lower portion to the upper portion is connected, and a pair of split-type holding portions having a cavity whose inner peripheral surface is tapered at the upper end of the shaft portion are formed in a pair. The split-type flange along the outer circumference is locked under spring pressure, and the inner peripheral surface of the large end of the connecting rod is broached when the jig descends, and at the same time it is split by expanding the split die It is characterized by doing.

The connecting rod cap dividing device for a forged connecting rod according to the present invention having the above-described structure, comprises a groove formed in a broach portion, and further a jig is lowered to provide a dividing die provided on the outer periphery of a small-diameter tapered shaft portion of the broach portion. Since the stress is converted from the vertical direction to the connecting rod axis direction, the division of the large end can be accurately performed with a small load.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a forged connecting rod for dividing a connecting rod cap according to an embodiment of the present invention; First, the manufacture of the connecting rod by forging will be described. Using a steel material as a connecting rod material, cutting in advance according to the material diameter cutting length according to the size, shape, volume of the connecting rod to be manufactured, heating this to a temperature suitable for forging, and then forming a required connecting rod C Formed by forging into shape. If necessary, hot coining may be performed after forging.

Next, this is cooled and subjected to shot blasting, and the large and small ends C of the connecting rod are subjected to rough machining.
The connecting rod is manufactured by cutting or the like so that the thickness direction of L and CS becomes a predetermined dimension, and making the inner diameter of the bearing hole the designed dimension. If necessary, cold coining may be performed before machining the large and small ends in the thickness direction.

The large end portion CL of the connecting rod C thus formed is divided into a connecting rod body C1 and a connecting rod cap C2. In order to perform this division accurately and reliably, the broaching is performed simultaneously with the division.

Next, a method of simultaneously performing broaching and division on the large end of the connecting rod will be described. The connecting rod C formed by forging is set at a fixed position on the division table T. From above the large end of the connecting rod, the jig 1 in which the broach and the split mold are integrated is lowered so as to be inserted into the large end hole.

In the embodiment shown in FIG. 1, the jig 1 has a pair of broaches 2 formed at the lower end of a split mold 3.
The broach 2 has a diameter slightly smaller than the hole diameter at the large end,
The broach blade 21 is formed so as to face the outer peripheral side surface in the longitudinal direction, and the broach blade 21 can cut a predetermined V-shaped groove on the inner peripheral surface of the hole at the large end as shown in FIG. At the outer surface of the broach. The split mold 3 connected to the broach 2 has a tapered shape whose lower part gradually increases in diameter upward from the outer diameter of the broach part, and the tapered part 31 is smoothly inserted into the large end hole. The diameter of the upper large-diameter portion is determined such that the large end portion is surely divided into two, and this large-diameter portion is made elliptical as shown in FIG.

In the embodiment shown in FIG. 1, the jig 1 is lowered into the large end of the connecting rod and the broach part 2 is strongly inserted, so that a V-shaped groove is engraved on the inner peripheral surface of the large end. When the jig 1 is further lowered in this state, the broach portion completely passes through the inside of the large end, the lower tapered portion 31 of the split mold 3 is inserted, and is pressed against the inner peripheral surface of the large end according to the insertion of the tapered portion. Then, stress gradually concentrates on the groove on the inner peripheral surface of the large end portion, and the connecting rod cap and the connecting rod body are accurately divided from this groove. In this way, the jig is lowered and inserted to a predetermined position, the large end is divided, and then raised again to wait for the next operation.

The lowering operation of the jig 1 uses a pressing method such as hydraulic pressure and applies a load such that the large end of the connecting rod is divided, but this may be steep or slow. By converting the vertical load into the horizontal load at the taper of the jig in this way, the large end breaks (divides) with a small load.
Becomes possible.

FIG. 4 shows another embodiment of the jig, in which a split mold is slidably fitted on the upper part of the broach. In this embodiment, a shaft portion 22 having a diameter smaller than the diameter of the broaching portion 2 is connected to the upper portion of the true cylindrical broaching portion 2 in a stepped manner, and the lower portion of the shaft portion 22 has a small diameter and the upper portion has a large diameter. And the shaft 2
At the upper end of 2, a split type holding portion 23 is formed. A cavity 24 is formed in the lower part of the split type holding part 23,
The inner peripheral surface of the cavity has a tapered surface 2 with a small diameter at the bottom and a large diameter at the top.
In this cavity, divided dies 32 and 33, which are divided into a plurality of two or three parts and are opposed to each other, are inserted and supported.

A split mold 32 which is divided into a plurality to form a pair,
33 has locking flanges 32b, 33b integrally formed on the upper part thereof, and the main body portions of the split dies 32, 33 facing each other have the outer peripheral surface along the entire inner peripheral surface of the hole at the large end, and The surface side is tapered so as to follow the outer peripheral portion tapered shape of the shaft portion 22, is disposed so as to hold the outer peripheral portion of the shaft portion 22, and the outer end surfaces of the locking flanges 32b and 33b are also tapered. The outer end surfaces of the locking flanges 32b and 33b are slidable along the inner peripheral surface of the cavity 24. Also, this locking collar 32
A return spring 34 is interposed between b, 33b and the inner top surface of the split mold holder 23.

Therefore, in the embodiment constructed as described above, the jig 1 is lowered and the broach part 2 of the jig 1 is strongly inserted into the large end of the connecting rod, so that a V-shaped groove is engraved on the inner peripheral surface of the large end. You. This is the same as the embodiment shown in FIG. Next, when the jig 1 is further lowered, the broaching part is also lowered and completely passes through the inside of the large end, and then the lower part of the split mold 3 is inserted into the large end. Then, the split mold is stopped by friction with the inner peripheral surface of the large end portion or in a state of being inserted into the large end portion by the stopper, but when the jig further descends, the shaft portion 22 of the broaching part also descends. At this time,
The return spring 34 bends when the shaft portion 22 of the broaching part is lowered, and only the shaft portion 22 is lowered. Since the shaft portion 22 has a tapered shape, the lowering of the broach portion after the split mold 3 is stopped in the large end portion moves the split mold from the vertical direction to the horizontal direction. Stress is generated in the axial direction of the connecting rod from the inner peripheral surface side of the large end portion by the amount of drop, and the stress is concentrated on the groove formed by broaching, and the large end portion is divided from this groove.

After the large end is divided, when the jig 1 is lifted, the split mold rises together with the broach part, and the split mold is lowered along the shaft by the return spring. At this time, since the inner peripheral surface of the cavity 24 of the split mold holding portion 23 has a tapered surface, the split molds are expanded outward by pressing the split locking flanges 32b and 33b with the tapered surface. And return it.

[0021]

According to the method for dividing a connecting rod cap in a forged connecting rod according to claim 1 of the present invention,
Since broaching is performed on the inner peripheral surface of the large end of the connecting rod at the same time as division by the same jig can be performed in one step, manufacturing is simplified, and there is an advantage that division can be accurately performed by broaching immediately before division.

Further, according to the connecting rod cap dividing device for a forged connecting rod according to the second aspect of the present invention, the broach portion provided with the broach blade is connected to the split mold via the tapered surface to form a single unit. Since the jig is configured by using the jig, there is an advantage that the jig is simplified, broaching and division can be performed at the same time, and the manufacturing process can be simplified.

According to the connecting rod cap dividing device for a forged connecting rod according to the third aspect of the present invention, after the groove is formed in the broaching portion, the outer periphery of the small diameter tapered shaft portion of the broaching portion is further lowered by lowering the jig. Since the stress is converted from the vertical direction to the connecting rod axis direction by the split mold provided in the above, the splitting of the large end can be accurately performed with a small load.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view showing a first embodiment of a connecting rod dividing device for a forged connecting rod according to the present invention during broaching.

FIG. 2 is a vertical sectional front view at the time of the division.

FIG. 3 is a side view of the same.

FIG. 4 is a longitudinal sectional front view of another embodiment of the present invention.

[Explanation of symbols]

 C Connecting rod CL Large end CS Small end T Division 1 Jig 2 Broach 21 Broach blade 22 Shaft 23 Split type holder 24 Cavity 3 Split type 31 Tapered surface 32 Split type 32a Tapered surface 32b Locking flange 33 Split type 33a tapered surface 33b locking flange 34 return spring

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-205238 (JP, A) JP-A-6-238600 (JP, A) JP-A-5-70828 (JP, A) 46823 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B21K 1/06 F16C 7/02

Claims (3)

(57) [Claims] In a method of dividing and forming a connecting rod cap by inserting a jig into a large end of a connecting rod manufactured by forging, a jig to be inserted and dropped into a large end of the connecting rod is divided into a split mold and a broach part. It is characterized in that broaching is performed in advance at the time of splitting at a broaching portion protruding from the lower end of the split mold, and then the connecting rod cap is split and molded from the front broach groove by the split die which descends. How to divide connecting rod caps in forged connecting rods. 2. A jig for forming a connecting rod cap by dividing from a large end of a connecting rod, a broaching section having a broaching blade at a lower end, and a splitting mold continuously formed at an upper portion thereof through a tapered surface. A splitting device for a connecting rod cap in a forged connecting rod, wherein the jig is forcibly pressed into a large end portion of the connecting rod to perform broaching and division at the same time. 3. A jig for forming a connecting rod cap which is divided from a large end portion of a connecting rod is provided on a broaching portion provided with a broaching blade. And
A pair of split-type holding portions having a cavity whose inner peripheral surface is tapered at the upper end of the shaft portion is formed, and a split-type flange portion along the outer periphery of the shaft portion is locked in the cavity under spring pressure. A splitting device for a connecting rod cap in a forged connecting rod, wherein broaching is performed on the inner peripheral surface of the large end portion of the connecting rod when the jig is lowered, and splitting is performed by expanding a split die.