JP2013006214A - Method for manufacturing divided type forged member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a divided type forged member which can accurately position a second member relative to a first member and also readily form a divided type connecting rod.SOLUTION: The method for manufacturing a divided type forged member includes: a first forging step of forming a positioning recess 39 in one of a body material 51 and a cap material 52; a second forging step of forging two members of a connecting rod body 21 and a cap 25 into a state where the connecting rod body 21 and the cap 25a are temporarily fixed at a temporary fixation part 53, and also forming a positioning projection 34 so as to correspond to the positioning recess; a machining step of machining the two members 21, 25 to form a locking part 29 therein; a fastening step of fastening the two members to each other with a bolt 27; a removing step of removing the temporary fixation part while fastening the two members; and a separating step of releasing the two members fastened by the bolt.

Description

  The present invention relates to a method of manufacturing a split forged member that can be fastened in a state in which a first member and a second member are abutted by fastening a first member and a second member with a fastening member.

A connecting rod (hereinafter referred to as “connecting rod”) is used as a member for connecting a piston to a crankshaft of an internal combustion engine (engine). The connecting rod includes two members, a connecting rod main body and a cap, for connection to a crankpin of the crankshaft.
Since the cap is assembled to the large end portion of the connecting rod main body with the fastening member, the large end portion and the cap are rotatably connected to the crank pin.

In this connecting rod, the connecting rod body and the cap material were forged with the material of the connecting rod body and the cap material being abutted, so that the abutting portions of the connecting rod body and the cap (hereinafter referred to as “mating portions”) were formed in an uneven shape. There is a split type connecting rod.
The mating portions are engaged with each other by forming the mating portions of the connecting rod main body and the cap in an uneven shape.

The connecting rod body and the cap are integrated by engaging the mating portion of the connecting rod body and the cap.
The connecting rod body and the cap are processed in an integrated state, and after the processing, an impact force is applied to the connecting rod body and the cap to separate the respective mating portions (for example, see Patent Document 1).

According to the split type connecting rod of Patent Document 1, an uneven portion (hereinafter referred to as “positioning uneven portion”) is formed in the mating portion of the large end portion, and an uneven portion (hereinafter referred to as “positioning uneven portion”) in the mating portion of the cap. ") Is formed.
When the large end portion and the cap are assembled with the fastening member, the cap can be accurately positioned with respect to the large end portion by fitting the positioning uneven portion of the cap to the positioning uneven portion of the large end portion (for example, Patent Documents). 1).

Japanese Patent No. 3811200

Here, the split-type connecting rod of Patent Document 1 meshes the positioning unevenness portion of the large end and the positioning unevenness portion of the cap to integrate the large end portion and the cap, and processes the integrated connecting rod body and cap. .
In order to integrate the large end portion and the cap, it is necessary to form the positioning concavo-convex portion of the large end portion and the positioning concavo-convex portion of the cap into an acute angle and firmly mesh with each other.

However, when the positioning irregularities of the large end and the cap are formed with acute angles, the positioning irregularities may be deformed when the connecting rod body and the cap are subjected to an impact force to separate the mating parts. .
For this reason, when separating the connecting rod main body (first member) and the cap (second member), it is necessary to apply an impact force so as not to deform the positioning concavo-convex portion, and it takes time to form (form) the connecting rod.

  The present invention provides a method for manufacturing a split forging member that can accurately position a second member (cap) with respect to a first member (connecting rod body) and that can easily form (form) a split connecting rod. Is an issue.

  In the invention according to claim 1, by forging the first material of the first member and the second material of the second member, a mating portion that can be brought into contact with each other is formed on the first material and the second material. A primary forging step of forming a positioning recess in at least one of the mating portions of the first material and the second material, and forging in a state in which the first material and the second material are butted at the mating portions, respectively. The first member and the second member are molded, and the first member and the second member are temporarily fixed by a temporary fixing portion, and a portion of the mating portion that faces the positioning concave portion is determined according to the positioning concave portion. A secondary forging step of forming the positioning convex portion by molding, and fastening the first member and the second member to the first member and the second member temporarily fixed by the temporary fixing portion. A processing step of processing a locking portion that can be locked by a possible fastening member, a fastening step of locking the fastening member to the locking portion and fastening the first member and the second member; A removing step of removing the temporary fixing portion in a state in which the one member and the second member are fastened by the fastening member, and the fastening of the first member and the second member by the fastening member is released to release the first member And a separation step of separating the second member into two members.

  According to a second aspect of the present invention, in the primary forging step, the first temporary fixing portion is integrally formed with the first material, and the second temporary fixing portion is integrally formed with the second material. And at least one of the second temporary fixing portions is formed with a temporary fixing groove extending in a direction perpendicular to the pressing direction by forging, and in the secondary forging step, the first member and the second member And forging the first temporary fixing part and the second temporary fixing part, the part facing the temporary fixing groove of the first temporary fixing part and the second temporary fixing part is The first temporary fixing portion and the second temporary fixing portion are temporarily fixed by molding according to the temporary fixing groove.

  According to a third aspect of the present invention, the first member is a connecting rod body having a large end portion that can be fitted to a crankpin, and the second member can be fastened to the large end portion of the connecting rod body by the fastening member. In the removing step, the temporary fixing portion is removed to form a fitting hole into which the crank pin can be fitted in the large end portion and the cap.

  According to a fourth aspect of the present invention, a pair of the positioning recesses are formed in at least one of the mating portions of the first material and the second material and in a portion corresponding to the periphery of the fastening member.

In the invention according to claim 1, in the secondary forging step, the first member and the second member are temporarily fixed by the temporary fixing portion, and the positioning convex portion is formed according to the positioning concave portion.
Thus, by positioning the positioning convex portion according to the positioning concave portion with the first member and the second member temporarily fixed, the positioning convex portion can be accurately molded with respect to the positioning concave portion.

Further, in the processing step, the locking portion is processed in the temporarily fixed first member and second member, and in the fastening step, the fastening member is locked in the locking portion and the first member and the second member are fastened. I made it.
In addition, in the removing step, the temporary fixing portion is removed in a state where the first member and the second member are fastened, and in the separating step, the fastening of the first member and the second member is released to release the first member and the second member. Was separated into two parts.

Here, the positioning convex portion is accurately formed with respect to the positioning concave portion.
Accordingly, when the second member is assembled to the first member divided into two members, the first member and the second member can be accurately positioned by aligning the positioning convex portion with the positioning concave portion.

According to the first aspect of the present invention, the positioning concave portion, the positioning convex portion, and the temporary fixing portion are provided independently of each other, and the temporary fixing portion is removed in the removing step.
By removing the temporary fixing portion in the removing step, the first member and the second member can be separated into two members simply by releasing the fastening by the fastening member in the separating step.
Therefore, unlike the prior art, it is not necessary to separate the first member and the second member by applying an impact force to the first member and the second member.
Thereby, the first member and the second member can be easily separated into two members, and the first member and the second member can be easily formed (formed).

In the invention which concerns on Claim 2, the temporary fix groove | channel was formed in at least one of the 1st temporary fix part and the 2nd temporary fix part in the primary forge process.
Therefore, in the secondary forging step, a part facing the temporary fixing groove can be formed according to the temporary fixing groove.
Here, the temporary fixing groove is extended in the direction orthogonal to the pressing direction by forging.

Therefore, in the secondary forging process, the first temporary fixing portion and the second temporary fixing portion are forged, whereby the width dimension of the temporary fixing groove is narrowed, and the portion formed according to the temporary fixing groove is temporarily fixed groove. It can be bitten with.
Thereby, by forging the first member and the second member, the first temporary fixing portion and the second temporary fixing portion can be easily temporarily fixed, and the first member and the second member are easily integrated. be able to.

By the way, in the primary forging step, the temporary fixing groove formed in at least one of the first temporary fixing part and the second temporary fixing part has a simple shape.
Thereby, it becomes possible to shape | mold easily the temporary fix part which has a temporary fix groove, and can shape | mold (form) a 1st member and a 2nd member much more easily.

In the invention according to claim 3, the first member is a connecting rod body, and the second member is a cap. Furthermore, in the removing step, the fitting end is formed in the large end portion and the cap by removing the temporary fixing portion capable of temporarily fixing the connecting rod body and the cap.
Therefore, the large end portion and the cap can be rotatably connected to the crank pin by fastening the large end portion and the cap with the fastening member and fitting the fitting hole into the crank pin.
Here, in the secondary forging step, when the connecting rod main body and the cap are forged, the positioning concave portion and the positioning convex portion are accurately formed on the connecting rod main body and the cap.
Thereby, a cap can be accurately positioned with respect to the large end part of a connecting rod main body.

According to the third aspect of the present invention, the positioning concave portion, the positioning convex portion, and the temporary fixing portion are provided individually (independently), and the temporary fixing portion is removed in the removing step.
By removing the temporary fixing portion in the removing step, the connecting rod body and the cap can be separated into two members simply by releasing the fastening by the fastening member in the separating step.
Therefore, unlike the prior art, it is not necessary to apply an impact force to the connecting rod body and the cap to separate the connecting rod body and the cap.
Thereby, the connecting rod body and the cap can be easily separated into two members, and the connecting rod body and the cap can be easily formed (formed).

  In the invention according to claim 4, a pair of positioning recesses are formed in a portion corresponding to the periphery of the fastening member. Therefore, a pair of positioning protrusions can be provided at a portion corresponding to the periphery of the fastening member by forming the positioning protrusions according to the positioning recesses.

Thereby, when assembling the first member and the second member, the pair of positioning concave portions can be engaged with the pair of positioning convex portions around the fastening member.
Accordingly, when the fastening member is tightened, the first member and the second member can be prevented from slightly shifting (rotating) in the rotational direction of the fastening member, so that the first member and the second member can be accurately placed at the normal positions. Can be assembled.

It is sectional drawing which shows the engine provided with the split die forge member (split die connecting rod) of Example 1 which concerns on this invention. It is a front view shown in the state which decomposed | disassembled the split type connecting rod of FIG. (A) is a 3a arrow view of FIG. 2, (b) is a 3b arrow view of FIG. It is sectional drawing which shows the state which assemble | attaches the split type connecting rod of FIG. 2 to a crankpin. FIG. 5 is an enlarged view of part 5 of FIG. 4. (A) is a perspective view which shows the positioning convex part of Example 1, (b) is a perspective view which shows the positioning recessed part of Example 1. FIG. 3 is a flowchart showing a method for manufacturing the split die forged member of Example 1. It is a figure explaining the example which shape | molds a main body raw material and a cap raw material in the primary forge process of Example 1. FIG. (A) is a front view which shows the cap raw material shape | molded in the primary forge process, (b) is a side view which shows the cap raw material shape | molded in the primary forge process. (A) is a perspective view which shows the state which has arrange | positioned the main body raw material and the cap raw material in the metal mold | die in the secondary forge process of Example 1, (b) shape | molds a connecting rod main body and a cap in the secondary forge process of Example 1. FIG. It is a top view explaining an example. 3 is an exploded perspective view showing a connecting rod body and a cap formed in a secondary forging step of Example 1. FIG. (A) is the sectional view on the 12a-12a line of FIG.10 (b), (b) is the sectional view on the 12b-12b line of FIG.10 (b). (A) is sectional drawing explaining the example which processes a latching | locking part to a large end part and a cap in the manufacturing process of Example 1, (b) is an example which fastens a large end part and a cap in the fastening process of Example 1. FIG. It is sectional drawing explaining the example which removes a temporary fix | stop part in the removal process of Example 1. FIG. It is sectional drawing explaining the example which isolate | separates a connecting rod main body and a cap in the isolation | separation process of Example 1. FIG. (A) is sectional drawing explaining the example which assembles | attaches a connecting rod main body and a cap to a crankpin in the assembly | attachment process of Example 1, (b) is the 16b part enlarged view of Fig.16 (a). It is sectional drawing explaining the example which guides a positioning recessed part with a positioning convex part in the assembly | attachment process of Example 1. FIG. It is sectional drawing which shows the state which assembled | attached the connecting rod main body and the cap to the crankpin in the assembly | attachment process of Example 1. FIG. It is a perspective view which shows the modification of the positioning convex part of Example 1, and a positioning recessed part. It is a front view shown in the state which decomposed | disassembled the split die forge member (split die connecting rod) of Example 2 which concerns on this invention. (A) is a 21a arrow view of FIG. 20, (b) is a 21b arrow view of FIG. It is a figure explaining the example which shape | molds a main body raw material and a cap raw material in the primary forge process of Example 2. FIG. (A) is a perspective view which shows the state which has arrange | positioned the main body raw material and the cap raw material in the metal mold | die in the secondary forge process of Example 2, (b) shape | molds a connecting rod main body and a cap in the secondary forge process of Example 2. FIG. It is a top view explaining an example. 6 is an exploded perspective view showing a connecting rod body and a cap formed in a secondary forging process of Example 2. FIG. (A) is sectional drawing explaining the example which attaches a connecting rod main body and a cap to a crankpin in the assembly process of Example 2, (b) is the state which contacted the connecting rod main body and the cap in the assembly process of Example 2. It is sectional drawing explaining the example which tightens a volt | bolt. (A) is the 26a enlarged view of FIG.25 (b), (b) is the 26b-26b sectional view taken on the line of FIG.25 (b).

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

A method for manufacturing the split die forged member according to the first embodiment will be described.
In the first embodiment, a split type connecting rod (hereinafter referred to as “split type connecting rod”) is illustrated as the split type forged member 20, but the split type forged member 20 is not limited to the split type connecting rod. For example, the split die forging member 20 according to the present invention can be applied to other split die forging members such as a split transmission case.

  As shown in FIG. 1, the engine 10 includes a piston 13 slidably provided in a cylinder portion 12 of an engine block 11, a crankshaft 16 provided in a crank chamber 15 of the engine block 11, A split-type connecting rod (split-type forged member) 20 capable of connecting the piston 13, a cylinder head 17 provided at the end 12 a of the cylinder portion 12, and an intake valve 18 and an exhaust valve 19 provided at the cylinder head 17. I have.

  As shown in FIG. 2, the split connecting rod 20 is fastened to a connecting rod body (first member) 21 capable of connecting the piston pin 14 and the crank pin 16 a (see also FIG. 1) and a large end 22 of the connecting rod body 21. A possible cap (second member) 25 and a pair of bolts (fastening members) 27 capable of fastening the cap 25 to the large end portion 22 are provided.

The connecting rod body 21 is an aluminum alloy forged member formed by forging.
The connecting rod body 21 includes a large end portion 22 that can be connected to a crank pin 16a (see also FIG. 1) of the crankshaft 16, a rod portion 23 connected to the large end portion 22, and an end portion 23a of the rod portion 23. And a small end portion 24 that can be connected to the piston pin 14.

The piston pin 14 is fitted in the mounting hole of the piston 13 and is fitted in the fitting hole 24 a of the small end portion 24.
As a result, the small end 24 is connected to the piston 13 via the piston pin 14.

As shown in FIGS. 3 and 4, the large end portion 22 includes a pair of screw holes (fastening holes) 31 formed at both end portions 22 a and a semicircular arc-shaped concave recess formed between the pair of screw holes 31. 32, a pair of mating portions 33 formed on both sides of the curved concave portion 32, and a positioning convex portion 34 formed on the pair of mating portions 33.
The positioning convex portion 34 is formed in a substantially conical shape (see also FIG. 6A).
Hereinafter, the mating portion 33 of the large end portion 22 is referred to as a “large end mating portion”.

The cap 25 is a forged member made of aluminum alloy formed by forging similarly to the connecting rod body 21, and is detachably fastened to the large end portion 22 via a pair of bolts 27.
The cap 25 includes a pair of through-holes 36 formed at both ends 25 a, a semicircular arc-shaped concave recess 37 formed between the pair of through-holes 36, and a pair of both-side portions of the curved recess 37. It has a mating portion 38 and a positioning recess 39 formed in the pair of mating portions 38.

A locking portion 29 is formed by the screw hole 31 of the large end portion 22 and the through hole 36 of the cap 25.
The positioning concave portion 39 is formed in a substantially conical shape (see also FIG. 6B) so as to correspond to the positioning convex portion 34.
Hereinafter, the matching portion 38 of the cap 25 is referred to as a “cap matching portion”.

The pair of cap alignment portions 38 are formed so as to be able to abut each of the pair of large end alignment portions 33.
Further, the pair of positioning projections 34 are formed so as to be engageable with the pair of positioning recesses 39 in a state where the pair of cap alignment portions are abutted against the pair of large end alignment portions.
In addition, the through hole 36 is formed so as to be coaxial with the screw hole 31 in a state where the pair of positioning convex portions 34 are engaged with the pair of positioning concave portions 39.

Further, the curved concave portion 37 of the cap 25 is formed so as to face the curved concave portion 32 of the large end portion 22 in a state where the pair of positioning convex portions 34 are engaged with the pair of positioning concave portions 39.
The curved concave portion 37 of the cap 25 and the curved concave portion 32 of the large end portion 22 face each other, whereby a fitting hole 26 (see FIG. 1) that can be fitted to the crankpin 16a is formed by the curved concave portions 32, 37. .

The bolt 27 is a fastening member in which a screw portion 27a is formed on the tip end side.
The cap 25 is detachably fastened to the large end portion 22 by inserting the bolt 27 into the through hole 36 and screwing the screw portion 27a protruding from the through hole 36 into the screw hole.
In this state, the pair of cap alignment portions 38 is held in a state of being abutted against the pair of large end alignment portions 33.

Further, the pair of positioning convex portions 34 is held in a state of being engaged with the pair of positioning concave portions 39.
By assembling the cap 25 to the large end portion 22, the large end portion 22 and the cap 25 are rotatably connected to the crank pin 16a.

As shown in FIGS. 5 and 6, the bolt 27 is formed with an outer diameter D1, and the through hole 36 is formed with a hole diameter D2.
The hole diameter D <b> 2 of the through hole 36 is larger than the outer diameter D <b> 1 of the bolt 27, and a gap 44 is formed between the through hole 36 and the bolt 27.
This gap 44 has a gap dimension (D2-D1) between the hole diameter D2 and the outer diameter D1.

The positioning convex part 34 is a convex part protruding in a substantially conical shape, the bottom part 34a is formed in the width dimension W1, and the top part 34b is located at the center of the bottom part 34a.
That is, the top 34b is located at a position that is 1/2 the width dimension W1 of the bottom 34a.
The positioning concave portion 39 is a concave portion recessed in a substantially conical shape so as to correspond to the positioning convex portion 34, the opening 39a is formed in the width dimension W2, and the bottom 39b is located at the center of the opening 39a.
That is, the bottom 39b is located at a position that is 1/2 of the width dimension W2 of the opening 39a.

The width dimension W2 is slightly larger than the width dimension W1.
By forming the width dimension W2 slightly larger than the width dimension W1, the positioning projection 34 is engaged with the positioning recess 39 with high accuracy.

Here, it is conceivable that the gap 44 is formed between the through hole 36 and the bolt 27, so that the large end portion 22 and the cap 25 are displaced.
That is, in the state where the bolt 27 is passed through the through hole 36 and the screw portion 27a is screwed to the screw hole 31, the large end portion 22 and the cap 25 may be displaced by a gap dimension (D2-D1). It is done.

Therefore, the width dimension W1 of the positioning convex portion 34 is made larger than the gap dimension (D2-D1), and the width dimension W2 of the positioning concave portion 39 is made larger than the gap dimension (D2-D1). That is,
(D2-D1) <W1
(D2-D1) <W2
The relationship was established.

By the way, as for the positioning convex part 34, the top part 34b is located in the half position (center of the bottom part 34a) of the width dimension W1 of the bottom part 34a. The positioning recess 39 has a bottom 39b located at a position half the width dimension W2 of the opening 39a (the center of the opening 39a).
Therefore, the width dimension W1 of the positioning convex part 34, the width dimension W2 of the positioning concave part 39, and the gap dimension (D2-D1) are:
Preferably,
2 × (D2-D1) <W1
2 × (D2-D1) <W2
The relationship was established.

Therefore, even when the gap between the large end portion 22 and the cap 25 is displaced by the gap dimension (D2-D1), the positioning recess 39 can be disposed within the width dimension W1 of the positioning protrusion 34 (see FIG. 5).
By positioning the positioning recess 39 within the width dimension W1, the positioning recess 39 can be automatically brought into contact with the positioning protrusion 34 when the bolt 27 penetrating the through hole 36 is screwed to the screw hole 31.
Therefore, the positioning concave portion 39 can guide the positioning concave portion 39 to the engagement position without visually confirming the positioning convex portion 34 and the positioning concave portion 39.
Thereby, the large end part 22 and the cap 25 can be assembled | attached easily and accurately.

Further, the width dimension W1 of the positioning protrusion 34 is smaller than the outer diameter D1 of the bolt 27, and the width dimension W2 of the positioning recess 39 is smaller than the outer diameter D1 of the bolt 27.
That is,
W1 <D1
W2 <D1
The relationship is established.
Thus, by establishing the relationship of W1 <D1 and W2 <D1, the area required for fastening of the large end 22 and the cap 25 is reduced, and the split connecting rod 20 (see FIG. 4) is made compact. Can do.

Next, an example in which the split die connecting rod 20 shown in FIG. 1 is manufactured by the method for manufacturing a split die forging member according to Embodiment 1 and the manufactured split connecting rod 20 is assembled to the engine 10 (see FIG. 1) is shown in FIGS. 18 will be described.
First, the process of manufacturing the split die connecting rod 20 by the manufacturing method of the split die forging member will be described with reference to FIGS.
As shown in FIGS. 7 and 8, in the primary forging step, the main body material (first material) 51 and the cap material (second material) 52 are formed by forging.
The body material 51 is a material from which the connecting rod body 21 (see FIG. 2) is molded. The cap material 52 is a material on which the cap 25 (see FIG. 2) is molded.

In the main body material 51, a pair of mating portions 33 that can abut against the cap material 52 are formed flat, and a first temporary fixing portion 54 is integrally formed between the pair of mating portions 33.
The first temporary fixing portion 54 has a flat temporary fixing surface 54a.

As shown in FIGS. 8 and 9, the cap material 52 has a pair of mating portions 38 that can be abutted against the main body material 51 formed flat, and a positioning recess 57 is formed in each of the pair of mating portions 38. Yes.
The positioning recess 57 is formed in a long hole shape when viewed from the front, and the bottom 57b is formed smaller than the opening 57a.
Specifically, the positioning recess 57 is formed in a long hole shape in front view so as to extend in a direction orthogonal to the direction pressed during forging.

Further, the cap material 52 has a second temporary fixing portion 55 formed integrally between the pair of mating portions 38.
The second temporary fixing portion 55 has a temporary fixing surface 55a that can be brought into contact with the temporary fixing surface 54a of the first temporary fixing portion 54, and a temporary fixing groove 61 formed in the temporary fixing surface 55a.
The temporary fixing groove 61 extends in a direction orthogonal to the pressing direction (arrow direction) when forging the cap 25 (see FIG. 2) from the cap material 52.

As shown in FIG. 7 and FIG. 10A, the main body material 51 and the cap material 52 are arranged in the mold 65 in the secondary forging process.
In this state, the pair of mating portions 38 (see FIG. 8) of the cap material 52 are abutted against the pair of mating portions 33 (see FIG. 8) of the main body material 51.
Furthermore, the temporary fixing surface 55a (see FIG. 8) of the second temporary fixing portion 55 is abutted against the temporary fixing surface 54a (see FIG. 8) of the first temporary fixing portion 54.

The mold 65 is operated to apply a pressing force in the direction of the arrow to the main body material 51 and the cap material 52, and the first temporary fixing part 54 and the second temporary fixing part 55.
The raw materials 51 and 52 and the temporary fixing portions 54 and 55 are forged by applying a pressing force to the raw materials 51 and 52 and the temporary fixing portions 54 and 55.

As shown in FIG. 10B, the connecting rod body 21 and the cap 25 are formed by forging the body material 51 and the cap material 52 (see FIG. 10A) with a mold 65.
At this time, a portion 33 a facing the positioning recess 57 in the mating portion 33 of the main body material 51 is molded (transferred) according to the positioning recess 57.
A portion 33 a that faces the positioning recess 57 in the mating portion 33 of the main body material 51 is hereinafter referred to as a “positioning transfer portion”.
The positioning transfer portion 33a (see FIG. 8) is formed on the positioning convex portion 34 by forming the positioning transfer portion 33a according to the positioning concave portion 57.

The main body material 51 and the cap material 52 are forged with the mold 65, and the first temporary fixing portion 54 and the second temporary fixing portion 55 (see FIG. 10A) are forged.
By forging the first temporary fixing portion 54 and the second temporary fixing portion 55, a portion 54b (see FIG. 8) facing the temporary fixing groove 61 of the temporary fixing surface 54a of the first temporary fixing portion 54 is temporarily fixed. Molding (transfer) according to 61.
The portion 54b facing the temporary fixing groove 61 in the temporary fixing surface 54a of the first temporary fixing portion 54 is hereinafter referred to as a “temporary fixing transfer portion”.

By forming the temporary fixing transfer portion 54b according to the temporary fixing groove 61, the formed temporary fixing convex portion 54c is engaged with the temporary fixing groove 61, and the first temporary fixing portion 54 and the second temporary fixing portion 55 are formed. Temporarily fix.
A temporarily fixed portion 53 is formed by the first temporarily fixed portion 54 and the second temporarily fixed portion 55 that are temporarily fixed.
Therefore, the main body material 51 and the cap material 52 are temporarily fixed together by the temporary fixing portion 53.

Here, the positioning concave portion 39 and the positioning convex portion 34 are formed in a substantially conical shape (see FIG. 6).
Therefore, when the positioning convex portion 34 is formed by forging according to the positioning concave portion 39, there is no possibility that the positioning convex portion 34 is bitten by the positioning concave portion 39.
That is, the positioning projection 34 is formed so as to be separable by forging according to the positioning recess 39.

As shown in FIGS. 11 and 12A, in the secondary forging step, the temporary fixing transfer portion 54b (see FIG. 8) can be formed according to the temporary fixing groove 61.
Here, the temporary fixing groove 61 extends in a direction orthogonal to the pressing direction by forging.

Therefore, in the secondary forging process, the first temporary fixing portion 54 and the second temporary fixing portion 55 are forged, so that the width dimension W3 of the temporary fixing groove 61 is narrowed and formed according to the temporary fixing groove 61. The temporary fixing convex portion 54 c can be engaged with the temporary fixing groove 61.
In particular, since the first temporary fixing portion 54 and the second temporary fixing portion 55 have a larger crushed amount by forging than the connecting rod main body 21 and the cap 25, the meat of the first temporary fixing portion 54 and the second temporary fixing portion 55 is large. The thickness dimension T is reduced.

Therefore, since the width dimension W <b> 3 of the temporary fixing groove 61 can be sufficiently narrowed, the formed temporary fixing convex portion 54 c can be firmly engaged with the temporary fixing groove 61.
Thus, by forging the connecting rod main body 21 and the cap 25, the first temporary fixing portion 54 and the second temporary fixing portion 55 can be easily temporarily fixed, and the connecting rod main body 21 and the cap 25 can be easily integrated. .

As shown in FIGS. 11 and 12B, when the connecting rod body 21 and the cap 25 are temporarily fixed by the temporary fixing portion 53 in the secondary forging step, the positioning concave portion 57 (see FIG. 8) is changed to the positioning concave portion 39. The positioning convex portion 34 is molded according to the positioning concave portion 39.
Thus, the positioning convex portion 34 can be accurately molded with respect to the positioning concave portion 39 by molding the positioning convex portion 34 according to the positioning concave portion 39 in a state where the connecting rod body 21 and the cap 25 are temporarily fixed.

Further, when the connecting rod body 21 and the cap 25 are forged, the positioning convex portion 34 can be formed according to the positioning concave portion 39.
Thereby, since the trouble which processes the positioning recessed part 39 and the positioning convex part 34 separately can be saved, the connecting rod main body 21 and the cap 25 can be shape | molded (formation) easily.

Here, as shown in FIGS. 8 and 9, the positioning recess 57 is formed in a long hole shape in plan view so as to extend in a direction orthogonal to the direction pressed during forging in the secondary forging process. The bottom 57b is formed (formed) smaller than the opening 57a.
In the secondary forging step, the mating portion 33 and the mating portion 38 are pressed in the direction of the arrow during forging, and are also pressed in the direction orthogonal to the arrow direction.
Therefore, as shown in FIG. 11, in the secondary forging process, the positioning concave portion 57 (see FIG. 8) is formed in the positioning concave portion 39, and the positioning convex portion 34 is formed in accordance with the positioning concave portion 39, whereby the positioning concave portion 39. And the positioning convex part 34 is shape | molded by substantially cone shape.

By the way, as shown in FIGS. 8 and 9, in the primary forging step, the temporary fixing groove 61 formed in the temporary fixing surface 55a of the second temporary fixing portion 55 has a simple linear shape.
Accordingly, the second temporary fixing portion 55 having the temporary fixing groove 61 can be easily formed, and the connecting rod body 21 and the cap 25 can be formed (formed) more easily.

  In the secondary forging step, the connecting rod body 21 and the cap 25 are forged from the body material 51 and the cap material 52, and then the connecting rod body 21 and the cap 25 integrated by the temporary fixing portion 53 are taken out from the mold.

As shown in FIGS. 7 and 13A, in the processing step, the locking portion 29 is processed into the connecting rod body 21 (large end portion 22) and the cap 25 that are temporarily fixed by the temporary fixing portion 53.
The locking portion 29 has a pair of through holes 36 processed in both end portions 25 a of the cap 25 and a pair of screw holes 31 processed in both end portions 22 a of the large end portion 22.
The through hole 36 is opened in the mating portion 38. The screw hole 31 is opened to the mating portion 33 and is formed coaxially with the through hole 36.

As shown in FIGS. 7 and 13B, in the fastening process, the bolt 27 is inserted into the through hole 36 of the cap 25 as shown by the arrow A, and the screw portion 27 a protruding from the through hole 36 is screwed to the screw hole 31. .
In this state, the head portion 27b of the bolt 27 comes into contact with the seat portion 25b of the cap 25, and the bolt 27 is locked to the through hole 36 and the screw portion 27a (that is, the locking portion 29).
Thus, the screw portion 27 a of the bolt 27 is screwed to the screw hole 31, and the head portion 27 b of the bolt 27 abuts against the seat portion 25 b of the cap 25, so that the large end portion 22 and the cap 25 are paired with the pair of bolts 27. It is concluded with.

As shown in FIGS. 7 and 14, in the removing step, the temporary fixing portion 53 (see FIG. 13B) is removed in a state where the large end portion 22 and the cap 25 are fastened with a pair of bolts 27.
By removing the temporary fixing portion 53, the fitting hole 26 into which the crank pin 16 a (see FIG. 1) can be fitted is formed in the large end portion 22 and the cap 25.
At the same time, a fitting hole 24 a into which the piston pin 14 (see FIG. 1) can be fitted is formed in the small end portion 24.

As shown in FIGS. 7 and 15 (a), in the separation step, the screw portion 27a of the bolt 27 is removed from the screw hole 31 and removed from the large end portion 22 and the cap 25 as indicated by an arrow B.
By removing the pair of bolts 27 from the large end 22 and the cap 25, the fastening of the large end 22 and the cap 25 by the bolt 27 is released.

  As shown in FIG. 15 (b), the large end 22 (connecting rod main body 21) and the cap 25 are released by releasing the fastening of the large end 22 and the cap 25 with a pair of bolts 27 (see FIG. 15 (a)). Is separated into two parts.

Here, in the secondary forging step, the positioning concave portion 39 and the positioning convex portion 34, and the temporary fixing portion 53 (see FIG. 13B) are provided independently and individually. And the temporary fix | stop part 53 was removed in the removal process.
By removing the temporary fixing portion 53 in the removing step, the large end portion 22 (the connecting rod main body 21) and the cap 25 can be separated into two members simply by releasing the fastening by the bolt 27 in the separating step.

Therefore, unlike the prior art, it is not necessary to apply an impact force to the large end portion (connecting rod body) and the cap to separate the connecting rod body and the cap.
This makes it possible to easily separate the large end 22 (connecting rod main body 21) and the cap 25 into two members, and to easily mold (form) the large end 22 (connecting rod main body 21) and the cap 25. Can do.

Next, an assembly process for assembling the split type connecting rod 20 manufactured by the method for manufacturing the split type forged member according to the present invention to the engine 10 (see FIG. 1) will be described with reference to FIGS.
As shown in FIG. 16 (a), the large end 22 (curved recess 32) of the connecting rod body 21 is opposed to a substantially half portion of the crank pin 16a on the piston 13 (see FIG. 1) side.
Further, the cap 25 (curved concave portion 37) is opposed to a substantially half portion of the crankpin 16a opposite to the piston 13 (see FIG. 1).

In this state, the pair of mating portions 38 of the cap 25 faces the pair of mating portions 33 of the large end portion 22.
With the pair of mating portions 38 facing the pair of mating portions 33, the bolts 27 are respectively inserted into the pair of through holes 36 formed in the cap 25 as indicated by arrows C.
By inserting the bolt 27 into the through hole 36, the screw portion 27 a protrudes from the through hole 36, and the screw portion 27 a protruding from the through hole 36 is screwed to the screw hole 31.

As shown in FIG. 16 (b), the hole diameter D 2 of the through hole 36 is larger than the outer diameter D 1 of the bolt 27. Therefore, in a state in which the threaded portion 27a of the bolt 27 is screw-coupled to the screw hole 31, the cap 25 is displaced downward (lowered) by its own weight by the gap dimension (D2-D1) from the normal mounting position.
Here, the relationship among the width dimension W1 of the positioning convex part 34, the width dimension W2 of the positioning concave part 39, and the gap dimension (D2-D1) is preferably
2 × (D2-D1) <W1
2 × (D2-D1) <W2
Is set to
Therefore, the opening 39 a of the positioning recess 39 faces the top 34 b of the positioning protrusion 34.

As shown in FIG. 17A, the screw portion 27 a of the bolt 27 is continuously screwed into the screw hole 31. Therefore, the cap 25 moves toward the mating portion 33 of the large end portion 22 as indicated by an arrow D.
As the cap 25 moves toward the mating portion 33 of the large end portion 22, the inclined surface 39 c of the positioning concave portion 39 contacts the top portion 34 b of the positioning convex portion 34.

As shown in FIG. 17B, the screw portion 27 a of the bolt 27 is continuously screwed to the screw hole 31. Therefore, the inclined surface 39 c of the positioning concave portion 39 is guided to the top portion 34 b of the positioning convex portion 34.
The positioning concave portion 39 engages with the positioning convex portion 34 by the inclined surface 39c being guided by the top portion 34b.

As shown in FIG. 18, the large end portion 22 and the cap 25 are fastened by the pair of bolts 27 by tightening the bolts 27 until the positioning concave portions 39 engage with the positioning convex portions 34.
In this state, the large end 22 and the cap 25 are assembled to the crankpin 16a.

Here, the positioning convex portion 34 is temporarily fixed to the connecting rod main body 21 and the cap 25 by the temporary fixing portion 53 (see FIG. 13B) and is formed according to the positioning concave portion 39 in the secondary forging step.
Therefore, the positioning convex part 34 can be accurately molded with respect to the positioning concave part 39.
As a result, the positioning concave portion 39 engages with the positioning convex portion 34, whereby the large end portion 22 and the cap 25 can be assembled to the crank pin 16a with high accuracy.

Further, the relationship among the width dimension W1 of the positioning protrusion 34, the width dimension W2 of the positioning recess 39 and the gap dimension (D2-D1) shown in FIG.
2 × (D2-D1) <W1
2 × (D2-D1) <W2
Set to.

Therefore, when the bolt 27 penetrating the through hole 36 is screwed to the screw hole 31, the positioning concave portion 39 can be automatically brought into contact with the positioning convex portion 34.
Accordingly, the positioning concave portion 39 can guide the positioning concave portion 39 to the engaging position without visually confirming the positioning convex portion 34 and the positioning concave portion 39.

  Thus, the pair of bolts 27 is formed by accurately forming the positioning convex portion 34 with respect to the positioning concave portion 39 and satisfying 2 × (D2-D1) <W1, 2 × (D2-D1) <W2. The connecting rod main body 21 and the cap 25 can be easily and accurately assembled to the crank pin 16a simply by tightening.

(Modification)
Next, a modification of the positioning convex portion 34 and the positioning concave portion 39 of the first embodiment will be described with reference to FIG.
A positioning convex portion 72 shown in FIG. 19 is obtained by changing the substantially conical positioning convex portion 34 (see FIG. 6A) described in the first embodiment into a substantially quadrangular pyramid shape.
The positioning convex portion 72 is formed in a substantially square shape with a bottom portion 72a having a width dimension W4 and a shortest width dimension (width dimension) W5.

A positioning recess 74 shown in FIG. 19 is obtained by changing the substantially conical positioning recess 39 (see FIG. 6B) described in the first embodiment into a substantially quadrangular pyramid shape.
The positioning recess 74 is formed in a substantially square shape with an opening 74a having a width dimension W6 and a shortest width dimension (width dimension) W7.

The width dimension W6 is formed slightly larger than the width dimension W4, and the shortest width dimension W7 is formed slightly larger than the shortest width dimension W5.
Therefore, the positioning convex part 72 can be suitably engaged with the positioning concave part 74 (accurately).

Furthermore, the shortest width dimension W5 of the positioning convex part 72 is made larger than the gap dimension (D2-D1) (see FIG. 5), and the shortest width dimension W7 of the positioning concave part 74 is made larger than the gap dimension (D2-D1). That is,
(D2-D1) <W5
(D2-D1) <W7
The relationship was established.
D1 is the outer diameter of the bolt 27, D2 is the hole diameter of the through hole 36, and the gap dimension (D2-D1) is the gap between the through hole 36 and the bolt 27.

By the way, as for the positioning convex part 72, the top part 72b is located in the position (center of the bottom part 72a) of 1/2 of the shortest width dimension W5 of the bottom part 72a. In addition, the positioning recess 74 has a bottom 74b located at a position half the width of the opening 74a (center of the opening 74a).
Therefore, the shortest width dimension W5 of the positioning convex part 72, the shortest width dimension W7 of the positioning concave part 74, and the gap dimension (D2-D1) are:
Preferably,
2 × (D2-D1) <W5
2 × (D2-D1) <W7
The relationship is established.

Therefore, the positioning recess 74 can be disposed within the shortest width dimension W5 of the positioning protrusion 72 even when the large end 22 and the cap 25 are displaced by a gap dimension (D2-D1).
Thereby, when the bolt 27 penetrated through the through hole 36 is screwed to the screw hole 31, the positioning concave portion 74 can be brought into contact with the positioning convex portion 72 (top portion 72b).
Therefore, when the bolt 27 is screwed to the screw hole 31, the positioning concave portion 74 can guide the positioning concave portion 74 to the engagement position, so that the large end portion 22 and the cap 25 can be assembled easily and accurately.

Here, the positioning concave portion 74 and the positioning convex portion 72 are formed in a substantially quadrangular pyramid shape.
Therefore, when the positioning convex portion 72 is formed by forging according to the positioning concave portion 74, there is no possibility that the positioning convex portion 72 is caught in the positioning concave portion 74.
That is, the positioning projection 72 is formed so as to be separable by forging according to the positioning recess 74.

Next, Example 2 will be described with reference to FIGS.
In addition, in the manufacturing method of the split die forging member of Example 2, the same code | symbol is attached | subjected about the same / similar member as Example 1, and description is abbreviate | omitted.

A method for manufacturing the split die forged member according to the second embodiment will be described.
In the second embodiment, as in the first embodiment, a split die connecting rod is exemplified as the split die forging member 80. However, the split die forging member 80 is not limited to the split die connecting rod. For example, the split die forging member 80 according to the present invention can be applied to other split die forging members such as a split transmission case.

  In Example 2, in order to facilitate understanding of the configuration of the split connecting rod 80, for convenience, one of the pair of mating portions 33 is denoted as 33A, and the other mating portion is denoted as 33B. One of the pair of matching portions 38 is indicated as 38A, and the other matching portion is indicated as 38B. Furthermore, one bolt of the pair of bolts 27 is shown as 27A, and the other bolt is shown as 27B.

  As shown in FIG. 20, the split-type connecting rod 80 includes a connecting rod body (first member) 81 capable of connecting the piston pin 14 and the crank pin 16a, and a cap (second member) that can be fastened to the large end portion 82 of the connecting rod body 81. Member) 85 and a pair of bolts (fastening members) 27A and 27B capable of fastening the cap 85 to the large end portion 82.

The connecting rod body 81 is provided with a large end portion 82 instead of the large end portion 22 of the first embodiment, and the other configuration is the same as that of the connecting rod body 21 of the first embodiment.
As shown in FIG. 21 (a), the large end portion 82 has a pair of mating portions 33A and 33B composed of one mating portion 33A and the other mating portion 33B, like the large end portion 22 of the first embodiment. .
The large end portion 82 has a pair of positioning convex portions 34 on one mating portion 33A and a pair of positioning convex portions 34 on the other mating portion 33B. Other configurations are the same as those in the first embodiment. Similar to the large end 22.

The pair of mating portions 33A and 33B are each formed in a substantially rectangular shape.
A pair of positioning projections 34 are provided close to each other on the diagonal line of one mating portion 33 </ b> A, and one screw hole 31 is formed between the pair of positioning projections 34.
That is, the pair of positioning projections 34 is provided around one screw hole 31.
Further, the pair of positioning convex portions 34 are provided close to each other on the diagonal line of the other mating portion 33 </ b> B, and a screw hole 31 is formed between the pair of positioning convex portions 34.
That is, the pair of positioning protrusions 34 are provided around the other screw hole 31.

As shown in FIG. 21B, the cap 85 has a pair of mating portions 38A and 38B including one mating portion 38A and the other mating portion 38B, like the cap 25 of the first embodiment.
The cap 85 has a pair of positioning recesses 39 provided on one mating portion 38A and a pair of positioning recesses 39 provided on the other mating portion 38B. The other configuration is the cap 25 of the first embodiment. It is the same.

The pair of mating portions 38A and 38B are each formed in a substantially rectangular shape, like the pair of mating portions 33A and 33B.
A pair of positioning recesses 39 are provided close to each other on the diagonal line of one mating portion 38 </ b> A, and a through hole 36 is formed between the pair of positioning recesses 39.
In other words, the pair of positioning recesses 39 are provided around one through hole 36.
In addition, a pair of positioning recesses 39 are provided close to each other on the diagonal line of the other mating portion 38 </ b> B, and a through hole 36 is formed between the pair of positioning recesses 39.
That is, the pair of positioning recesses 39 are provided around the other through hole 36.

Next, an example in which the split die connecting rod 80 shown in FIG. 20 is manufactured by the method for manufacturing a split die forging member according to Example 2 and the manufactured split die connecting rod 80 is assembled to the engine 10 (see FIG. 1) is shown in FIGS. 26 will be described.
First, the process of manufacturing the split die connecting rod 80 by the split die forging member manufacturing method will be described with reference to FIGS.

As shown in FIG. 22, in the primary forging step, a main body material (first material) 87 and a cap material (second material) 88 are formed by forging.
The body material 87 is a material from which the connecting rod body 81 (see FIG. 20) is molded. The cap material 88 is a material on which the cap 85 (see FIG. 20) is molded.

The cap material 88 has a pair of positioning recesses 57 formed on one mating portion 38A and a pair of positioning recesses 57 formed on the other mating portion 38B. The other configuration is the same as that of the cap material 52 of the first embodiment. It is the same.
That is, four positioning recesses 57 are formed in the pair of mating portions 38A and 38B.

A pair of positioning recesses 57 formed in one mating portion 38A is provided at a portion corresponding to the periphery of one bolt 27A (see FIG. 25A).
Further, the pair of positioning recesses 57 formed in the other mating portion 38B is provided at a portion corresponding to the periphery of the other bolt 27B (see FIG. 25A).

The main body material 87 has a portion 33a that faces the pair of positioning recesses 57 in one mating portion 33A, and a portion 33a that faces the pair of positioning recesses 57 in the other mating portion 33B. This is the same as the main body material 51 of the first embodiment.
Hereinafter, the portion 33a facing the positioning recess 57 is referred to as a “positioning transfer portion”.
Therefore, four positioning transfer portions 33a are formed in the pair of mating portions 33A and 33B.

As shown in FIG. 23A, the main body material 87 and the cap material 88 are placed in the mold 65 in the secondary forging process.
In this state, the mold 65 is operated to apply a pressing force in the direction of the arrow to the main body material 87 and the cap material 88, and the first temporary fixing portion 54 and the second temporary fixing portion 55, so that the materials 87, 88 and temporary Stop parts 54 and 55 are forged.

As shown in FIGS. 22 and 23B, the connecting rod main body 81 and the cap 85 are formed by forging the main body material 87 and the cap material 88 (see FIG. 23A) with a mold 65.
At this time, of the pair of mating portions 33A and 33B of the main body material 87, the four positioning transfer portions 33a are respectively molded (transferred) according to the four positioning recesses 57.
As a result, the pair of positioning transfer portions 33 a provided on one mating portion 33 </ b> A is formed into a pair of positioning convex portions 34. Similarly, a pair of positioning transfer portions 33a provided on the other mating portion 33B is formed into a pair of positioning convex portions 34.

  Further, by forging the main body material 87 and the cap material 88 (see FIG. 23A) with the mold 65, the main body material 87 and the cap material 88 are temporarily integrated with the temporary fixing portion 53 as in the first embodiment. Stopped.

As shown in FIG. 24, when the connecting rod body 81 and the cap 85 are temporarily fixed by the temporary fixing portion 53 in the secondary forging step, a pair of positioning recesses 57 provided in one mating portion 38A (see FIG. 22). Is formed into a pair of positioning concave portions 39, and a pair of positioning convex portions 34 is formed in one mating portion 33A.
Similarly, as shown in FIG. 21, a pair of positioning concave portions 57 (see FIG. 22) provided in the other mating portion 38B are formed into a pair of positioning concave portions 39, and a pair of positioning convex portions are formed in the other mating portion 33B. 34 was molded.

  Subsequent processes of the secondary forging process, that is, a processing process, a fastening process, a removing process, and a separating process are the same as those in the first embodiment, and thus description of each process is omitted.

Next, an assembling process for assembling the split type connecting rod 80 manufactured by the method for manufacturing the split type forged member according to the present invention to the engine 10 (see FIG. 1) will be described with reference to FIGS.
As shown in FIG. 25A, the large end portion 82 (curved concave portion 32) and the cap 85 (curved concave portion 37) of the connecting rod main body 81 are opposed to the crank pin 16a.
In this state, the pair of mating portions 38A and 38B of the cap 85 face the pair of mating portions 33A and 33B of the large end portion 82, respectively.

In this state, the pair of bolts 27A and 27B are respectively inserted into the pair of through holes 36 formed in the cap 85 as indicated by arrows E.
By inserting each bolt 27 </ b> A, 27 </ b> B into the through hole 36, the screw portion 27 a protrudes from the through hole 36, and the screw portion 27 a protruding from the through hole 36 is screwed to the screw hole 31.

As shown in FIG. 25 (b), by tightening the pair of bolts 27A and 27B as indicated by the arrow F, the pair of positioning recesses 39 provided in one of the mating portions 38A is provided in the one mating portion 33A. Engage with the pair of positioning protrusions 34.
Similarly, a pair of positioning concave portions 39 provided in the other mating portion 38B engages with a pair of positioning convex portions 34 provided in the other mating portion 33B.

As shown in FIG. 26 (a), a pair of positioning recesses 39 is provided in one mating portion 38A in a state of being close to a diagonal line (see also FIG. 21 (b)). In addition, a pair of positioning projections 34 are provided on one mating portion 33A so as to be close to a diagonal line (see also FIG. 21A).
Further, the pair of positioning concave portions 39 and the pair of positioning convex portions 34 are provided around one bolt 27A.

Therefore, as shown in FIGS. 26A and 26B, the pair of positioning recesses 39 engages with the pair of positioning protrusions 34 around (in the vicinity of) one bolt 27A. Thereby, when one bolt 27A is tightened in the direction of arrow F, it is possible to better prevent the one mating portion 38A from slightly shifting (rotating) in the rotation direction of the bolt 27A.
Therefore, the one mating portion 38A can be positioned at the regular mounting position with respect to the one mating portion 33A.

Similarly, as shown in FIGS. 21 and 25 (b), a pair of positioning recesses 39 are provided in the other mating portion 38B in a state of being close to a diagonal line. Further, a pair of positioning convex portions 34 are provided on the other mating portion 33B in a state of being close to a diagonal line.
Further, the pair of positioning concave portions 39 and the pair of positioning convex portions 34 are provided around the other bolt 27B.

Therefore, as shown in FIG. 25B, the pair of positioning recesses 39 engage with the pair of positioning protrusions 34 around (near) the other bolt 27B. Thereby, when the other bolt 27B is tightened in the direction of arrow F, it is possible to better prevent the other mating portion 38B from slightly shifting (rotating) in the rotation direction of the bolt 27B.
Therefore, since the other mating portion 38B can be positioned at the regular attachment position with respect to the other mating portion 33B, the cap 85 can be assembled to the regular position with respect to the large end portion 82 with higher accuracy.

In addition, the manufacturing method of the split die forging member according to the present invention is not limited to the above-described embodiment, and can be appropriately changed and improved.
For example, in the first embodiment and the second embodiment, the split die connecting rod 20 is exemplified as the split die forging member, but the split die forging member is not limited to this.
For example, the split die forging member according to the present invention can be applied to other split die forging members such as a split type transmission case.

  In the first embodiment and the second embodiment, the example in which the screw holes 31 are provided in the large end portions 22 and 82 and the through holes 36 are provided in the caps 25 and 85 has been described. It is also possible to provide the through holes 36 in the end portions 22 and 82 and provide the screw holes 31 in the caps 25 and 85.

Further, in the first embodiment and the second embodiment, the example in which the positioning concave portion 39 is provided in the caps 25 and 85 and the positioning convex portion 34 is provided in the connecting rod main bodies 21 and 81 has been described. It is also possible to provide the positioning protrusions 34 at 25 and 85 and the positioning recess 39 at the connecting rod bodies 21 and 81.
Alternatively, the positioning recesses 39 can be provided on the caps 25 and 85 and the connecting rod bodies 21 and 81, and the positioning protrusions 34 can be provided on the caps 25 and 85 and the connecting rod bodies 21 and 81.
Furthermore, it is also possible to provide the positioning recess 39 in the caps 25 and 85 and the connecting rod bodies 21 and 81 and to provide the positioning protrusion 34 in the caps 25 and 85 and the connecting rod bodies 21 and 81.

Moreover, in the said Example 1 and the said Example 2, the positioning recessed part 39 and the positioning convex part 34 are formed in a substantially cone shape by changing the shape of the positioning recessed part 57 shape | molded in the primary forging process in a secondary forging process. Although an example has been described, it is not limited to this.
For example, the secondary forging step can be performed without changing the shape of the positioning recess formed in the primary forging step.

In the first and second embodiments, the positioning convex portion 34 and the positioning concave portion 39 are formed in a substantially conical shape, and the positioning convex portion 72 and the positioning concave portion 74 are formed in a substantially quadrangular pyramid shape. The shape of the part and the positioning recess is not limited to this.
For example, the positioning convex portion and the positioning concave portion can be formed in other shapes such as a polygonal pyramid shape and a cylindrical shape.

In the second embodiment, an example in which a pair of positioning convex portions 34 is provided on the diagonal line of the pair of mating portions 33A and 33B and a pair of positioning concave portions 39 is provided on the diagonal line of the pair of mating portions 38A and 38B will be described. However, the present invention is not limited to this.
For example, a pair of positioning convex portions 34 can be provided on one side of the pair of mating portions 33A and 33B, and a pair of positioning concave portions 39 can be provided on the one side of the pair of mating portions 38A and 38B.

  Furthermore, the engine 10, the crankpin 16a, the split type connecting rods (split type forging members) 20, 80, the connecting rod main bodies (first members) 21, 81, the large end portion 22, 82, caps (second members) 25 and 85, locking portions 29, mating portions 33 and 38, positioning convex portions 34 and 72, positioning concave portions 39 and 74, main body materials (first materials) 51 and 87, cap materials ( The shape and configuration of the second material) 52, 88, the temporary fixing portion 53, the first temporary fixing portion 54, the second temporary fixing portion 55, the temporary fixing groove 61, and the like are not limited to those illustrated, and can be appropriately changed. It is.

  INDUSTRIAL APPLICABILITY The present invention is suitable for application to a method for manufacturing a split forged member that can be assembled in a state in which the first member and the second member are abutted by fastening the first member and the second member with a fastening member. It is.

  DESCRIPTION OF SYMBOLS 10 ... Engine, 16a ... Crankpin, 20, 80 ... Split type connecting rod (split type forging member) 21, 81 ... Connecting rod main body (first member), 22, 82 ... Large end, 25, 85 ... Cap (No. 2), 26 ... fitting hole, 27 ... bolt (fastening member), 27A ... one bolt, 27B ... the other bolt, 29 ... locking part, 33, 38 ... mating part, 33A, 38A ... one mating , 33B, 38B ... the other mating part, 33a ... part facing the positioning recess (positioning transfer part), 34, 72 ... positioning convex part, 39, 74 ... positioning recess, 51, 87 ... main body material (first material) ), 52, 88: Cap material (second material), 53: Temporary fixing portion, 54: First temporary fixing portion, 54b: A portion facing the temporary fixing groove (temporary fixing transfer portion), 54c: Temporary fixing convex portion 55 ... second temporary fixing part 61 ... temporary fixing groove.

Claims (4)

By forging the first material of the first member and the second material of the second member, the first material and the second material are formed with a mating portion that can be brought into contact with each other, and the first material and the second material A primary forging step of forming a positioning recess in at least one of the mating portions of the two materials;
The first member and the second member are formed by forging in a state where the first material and the second material are abutted at each mating portion, and the first member and the second member are temporarily fixed by the temporary fixing portion. A secondary forging step of forming a positioning convex portion by forming a portion facing the positioning concave portion of the mating portion according to the positioning concave portion;
A processing step of processing a locking portion capable of locking a fastening member capable of fastening the first member and the second member to the first member and the second member temporarily fixed by the temporary fixing portion;
A fastening step of fastening the first member and the second member by locking the fastening member to the locking portion;
A removing step of removing the temporary fixing portion in a state in which the first member and the second member are fastened by the fastening member;
A separation step of releasing the fastening of the first member and the second member by the fastening member and separating the first member and the second member into two members;
A method for producing a split die forging member, comprising: In the primary forging step,
The first temporary fixing portion is integrally formed with the first material, and the second temporary fixing portion is integrally formed with the second material,
At least one of the first temporary fixing part and the second temporary fixing part is formed with a temporary fixing groove extending in a direction perpendicular to the pressing direction by forging,
In the secondary forging step,
While forging the first member and the second member, forging the first temporary fixing portion and the second temporary fixing portion,
Of the first temporary fixing portion and the second temporary fixing portion, the first temporary fixing portion and the second temporary fixing portion are formed by forming a portion facing the temporary fixing groove according to the temporary fixing groove. The method for manufacturing a split die forged member according to claim 1, wherein the method is temporarily fixed. The first member is
It is a connecting rod body having a large end that can be fitted to a crankpin,
The second member is
A cap that can be fastened to the large end of the connecting rod body with the fastening member;
In the removing step,
The split die forging according to claim 1, wherein a fitting hole into which the crank pin can be fitted is formed in the large end portion and the cap by removing the temporary fixing portion. Manufacturing method of member.   2. The split die forging according to claim 1, wherein a pair of the positioning recesses are formed in at least one of the mating portions of the first material and the second material and a portion corresponding to the periphery of the fastening member. Manufacturing method of member.

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