JP5674555B2 - Split die forging - Google Patents

Description

  The present invention relates to a split forging member that can be assembled in a state in which a first member and a second member are abutted together 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.

  According to this connecting rod, 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 engaging the positioning concave portion of the cap with the positioning convex portion of the large end portion. (For example, refer to Patent Document 1).

JP 59-99108 A

However, in order to accurately position the cap with respect to the large end, it is necessary to form the positioning convex portion of the large end and the positioning concave portion of the cap with high accuracy.
For this reason, it takes time and effort to form (form) the large end (first member) and cap (second member) of the connecting rod main body, which has hindered cost reduction.

  The present invention provides 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) the first member and the second member. This is the issue.

In the invention according to claim 1, the first member and the second member have a matching portion that can abut each other, and a positioning recess is provided in at least one of the matching portions of the first member and the second member, The positioning recess has a bottom and an opening, the bottom is formed small with respect to the opening, and the first member and the second member are forged to abut each other at the mating portions. The first member and the second member are temporarily fixed by a temporary fixing portion, and the positioning concave portion is formed in a substantially conical shape or a substantially pyramid shape, and at the same time, a portion of the mating portion that faces the positioning concave portion but substantially conical shape, is formed in the positioning projection in accordance with the positioning recess formed in a substantially pyramidal shape, the said first member and said second member is temporarily fixed by the temporary fixing portions, the first portion And the latching | locking part which can latch the fastening member which can fasten the said 2nd member is processed, The said fastening member was latched by the said latching | locking part, and the said 1st member and the said 2nd member were fastened In the state where the temporary fixing portion is removed and the fastening of the first member and the second member by the fastening member is released, the first member and the second member are positioned by the positioning concave portion and the positioning convex portion. It is possible to do this.

  According to a second aspect of the present invention, the temporary fixing portion includes a first temporary fixing portion provided integrally with the first member, and a second temporary fixing portion provided integrally with the second member. At least one of the stop portion and the second temporary stop portion is provided with a temporary stop groove extending in a direction perpendicular to the pressing direction by forging, and the first member and the second member are forged. When the first temporary fixing portion and the second temporary fixing portion are forged, a portion of the first temporary fixing portion and the second temporary fixing portion that faces the temporary fixing groove is the temporary fixing groove. The first temporary fixing part and the second temporary fixing part are temporarily fixed by molding according to the above.

  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. A fitting hole that can be fitted to the crank pin is formed in the large end portion and the cap by removing the temporary fixing portion, and the large end portion and the cap are formed by the fastening member. By being fastened, the crank pin can be rotatably connected.

In the invention according to claim 1, by forging the first member and the second member, 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. I made it.
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.

Furthermore, after processing the locking portion in a state where the first member and the second member are temporarily fixed, the temporary fixing portion is locked in a state where the locking member is locked to the locking portion and the first member and the second member are fastened. It was made to remove.
Therefore, the first member and the second member can be divided into two members by removing the fastening member from the locking portion and releasing the fastening of the first member and the second member.
Here, by forging the first member and the second member, the positioning concave portion is formed in a substantially conical shape or a substantially pyramid shape, and a portion facing the positioning concave portion is formed into a positioning convex portion according to the positioning concave portion. . Therefore, there is no possibility that the positioning convex part is caught in the positioning concave part.
That is, the positioning convex portion is formed so as to be separable by forging according to the positioning concave portion.

Furthermore , the positioning convex part is accurately shape | molded with respect to the positioning recessed part by shape | molding the positioning convex part according to a positioning recessed part in the state which temporarily fixed the 1st member and the 2nd member.
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.

Further, when forging the first member and the second member, the positioning convex portion can be formed according to the positioning concave portion.
Thereby, since the effort which processes a positioning recessed part and a positioning convex part separately can be saved, a 1st member and a 2nd member can be shape | molded (formation) easily.

In the invention which concerns on Claim 2, the temporary fix part was comprised by the 1st temporary fix part and the 2nd temporary fix part. Furthermore, the temporary fixing groove extended in the direction orthogonal to the pressing direction by forging was provided in at least one of the first temporary fixing part and the second temporary fixing part.
Therefore, when the first member and the second member are forged, the first temporary fixing portion and the second temporary fixing portion are forged, and a portion 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, by forging the first temporary fixing portion and the second temporary fixing portion, the width dimension of the temporary fixing groove is narrowed, and the portion formed according to the temporary fixing groove can be bitten by the temporary fixing groove. it can.
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 can be easily integrated. Can be

By the way, 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. Further, by removing the temporary fixing portion capable of temporarily fixing the connecting rod body and the cap, a fitting hole is formed in the large end portion 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, when forging the connecting rod main body and the cap, the positioning concave portion and the positioning convex portion can be accurately formed in the connecting rod main body and the cap by temporarily fixing 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.

Moreover, when forging a connecting rod main body and a cap, a positioning convex part can be shape | molded according to a positioning concave part in a connecting rod main body or a cap.
Thereby, since the trouble of individually processing the positioning concave portion and the positioning convex portion can be saved, the connecting rod body and the cap can be easily formed (formed).

It is sectional drawing which shows the engine provided with the split die forge member (split die connecting rod) 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 which concerns on this invention, (b) is a perspective view which shows the positioning recessed part which concerns on this invention. It is a flowchart which shows the process of manufacturing the split type connecting rod which concerns on this invention, and the process of assembling a connecting rod to an engine. 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 which concerns on this invention. (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 which concerns on this invention, (b) shape | molds a connecting rod main body and a cap by the secondary forge process which concerns on this invention. It is a top view explaining an example. It is a disassembled perspective view which shows the connecting rod main body and cap which were shape | molded in the secondary forge process which concerns on this invention. (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 which concerns on this invention, (b) is an example which fastens a large end part and a cap in the fastening process which concerns on this invention FIG. It is sectional drawing explaining the example which removes a temporary fix | stop part in the removal process which concerns on this invention. It is sectional drawing explaining the example which isolate | separates a connecting rod main body and a cap in the isolation | separation process which concerns on this invention. (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 based on this invention, (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 which concerns on this invention. It is sectional drawing which shows the state which attached the connecting rod main body and the cap to the crankpin in the assembly | attachment process which concerns on this invention. It is a perspective view which shows the modification of the positioning convex part and positioning concave part which concern on this invention.

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

The divided die forging member 20 according to the embodiment will be described.
In the 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-type connecting rod 20 shown in FIG. 1 is manufactured and the manufactured split-type connecting rod 20 is assembled to the engine 10 will be described with reference to FIGS.
First, the process for manufacturing the split connecting rod 20 by forging 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 primary forging step ( 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 assembling process for assembling the split connecting rod 20 to the engine 10 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 modified example of the positioning convex portion 34 and the positioning concave portion 39 of the 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 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 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.

The split forging member according to the present invention is not limited to the above-described embodiments, and can be appropriately changed and improved.
For example, in the above 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.

  Moreover, in the said Example, although the screw hole 31 was provided in the large end part 22, and the example which provided the through-hole 36 in the cap 25 was demonstrated, not only this but the through-hole 36 was provided in the large end part 22, It is also possible to provide a screw hole 31 in the cap 25.

  Further, in the above-described embodiment, the example in which the positioning concave portion 39 is provided in the cap 25 and the positioning convex portion 34 is provided in the connecting rod main body 21 has been described. However, the present invention is not limited thereto. It is also possible to provide a positioning recess 39 in the main body 21.

Moreover, in the said Example, although the shape of the positioning recessed part 57 shape | molded in the primary forging process was changed in the secondary forging process, the example which forms the positioning recessed part 39 and the positioning convex part 34 in substantially cone shape was demonstrated. However, the present invention 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.

Further, in the above embodiment, the example in which 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 has been described, but the shape of the positioning convex portion and the positioning concave portion is described. 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.

  Further, the engine 10, the crankpin 16a, the split type connecting rod (split type forged member) 20, the connecting rod main body (first member) 21, the large end portion 22, the cap (second member) 25, the locking shown in the above embodiment. Shapes and configurations of the portion 29, the mating portions 33 and 38, the positioning convex portions 34 and 72, the positioning concave portions 39 and 74, the temporary fixing portion 53, the first temporary fixing portion 54, the second temporary fixing portion 55, and the temporary fixing groove 61 Is not limited to those illustrated, and can be changed as appropriate.

  The present invention is suitable for application to a split-type forged member that can be assembled in a state in which the first member and the second member are abutted together by fastening the first member and the second member with the fastening member.

DESCRIPTION OF SYMBOLS 10 ... Engine, 16a ... Crank pin, 20 ... Split type connecting rod (split type forging member), 21 ... Connecting rod main body (first member), 22 ... Large end, 25 ... Cap (second member), 26 ... Fitting Holes, 27 ... bolts (fastening members), 29 ... locking parts, 33, 38 ... mating parts, 33a ... parts facing the positioning concave parts (positioning transfer parts), 34, 72 ... positioning convex parts, 39, 57, 74 ... Positioning concave part, 53 ... Temporary fixing part, 54 ... First temporary fixing part, 54b ... Part facing the temporary fixing groove (temporary fixing transfer part), 54c ... Temporary fixing convex part, 55 ... Second temporary fixing part, 57a ... opening, 57b ... bottom, 61 ... temporary fixing groove.

Claims (3)

The first member and the second member have a mating portion that can be butted against each other, and a positioning recess is provided in at least one of the mating portions of the first member and the second member,
The positioning recess has a bottom and an opening, and the bottom is formed smaller than the opening;
The first member and the second member are forged into a state in which the first member and the second member are abutted at each mating portion, whereby the first member and the second member are temporarily fixed by the temporary fixing portion, and the positioning recess is Formed in a substantially conical shape, a substantially pyramidal shape,
At the same time, a portion of the mating portion that faces the positioning recess is formed into a positioning convex portion according to the positioning recess formed in a substantially conical shape or a substantially pyramid shape ,
The first member and the second member temporarily fixed by the temporary fixing portion are processed with a locking portion capable of locking a fastening member capable of fastening the first member and the second member,
The temporary fixing portion is removed in a state where the fastening member is locked to the locking portion and the first member and the second member are fastened.
The division characterized in that the first member and the second member can be positioned by the positioning concave portion and the positioning convex portion in a state where the fastening of the first member and the second member by the fastening member is released. Die forging member. The temporary fixing portion includes a first temporary fixing portion provided integrally with the first member, and a second temporary fixing portion provided integrally with the second member,
At least one of the first temporary fixing part and the second temporary fixing part is provided with a temporary fixing groove extending in a direction orthogonal to the pressing direction by forging,
While the first member and the second member are forged, the first temporary fixing part and the second temporary fixing part are forged,
Of the first temporary fixing portion and the second temporary fixing portion, a portion facing the temporary fixing groove is formed according to the temporary fixing groove, whereby the first temporary fixing portion and the second temporary fixing portion. The divided die forging member according to claim 1, wherein 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;
By removing the temporary fixing portion, a fitting hole that can be fitted to the crank pin is formed in the large end portion and the cap,
3. The split die forging member according to claim 1, wherein the large end portion and the cap are rotatably coupled to the crank pin by being fastened by the fastening member. .

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