JP2545277B2 - Conrod closing forging device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a closed forging device for connecting rods, which is capable of performing composite forming of connecting rod materials in a short cycle time by a single-acting press device.

BACKGROUND OF THE INVENTION In an internal combustion engine, as a method of manufacturing a connecting rod that connects a piston and a crankshaft, forging using a pressing device is generally used.

Therefore, FIG. 1 shows a finished product of a general connecting rod. That is, the connecting rod 2 has small end portions 6 connected to the piston side at both end portions of a connecting rod portion 4 having a substantially H-shaped cross section,
It has a large end 8 connected to the crankshaft side. As described above, since the connecting rod 2 has a significant difference in shape between the connecting rod portion 4, the small end portion 6 and the large end portion 8, the forming requires a high forging technique and a large number of steps. .

By the way, in recent years, processing of connecting rods by closed forging has been performed. This is because the closed forging has an advantage that a plurality of forming processes in each stage can be collectively performed. As a conventional technique in which such a closed forging is applied to the processing of a connecting rod, there is a closed forging method disclosed in JP-A-59-133928. In this closed forging method, first, the upper and lower surfaces of the material are roughly formed by the upper and lower split dies, then the side surfaces of the material are roughly formed by the side split dies, and then the upper and lower split dies and the side split dies are formed. The punch is inserted while the material is kept closed by the mold to form the large end and the small end of the connecting rod material.

In this case, the forming of the connecting rod material is performed in a cycle in which a series of steps are integrated, but since the forming is sequentially performed three times, the time required for one cycle becomes long. Therefore, even if the billet is heated in the stage, there is a disadvantage that the temperature is lowered and the heating is required again before the next finishing process is performed. In addition, the upper and lower split dies, the side split dies, and the press device equipped with the double-acting mechanism for multiple axes for displacing the punches are indispensable, so the manufacturing equipment must be large-scaled. .

[Object of the Invention] The present invention has been made to overcome the above-mentioned inconvenience, and a preformed body of a connecting rod that is formed in advance so that the axial length and the volume distribution of each part are substantially equal to the product. Is prepared, a side shape is formed by a split die on this preformed body, and then a large end is formed by a punch while being closed by the split die. It is an object of the present invention to provide a closed forging device for a connecting rod that can perform accurate composite molding by shortening the time required for one cycle using the device.

[Means for Achieving the Object] In order to achieve the above object, the present invention provides a small bulge portion formed on one end side and a large bulge portion formed on the other end side.
A rod portion formed between the small bulge portion and the large bulge portion is formed to have a length substantially equal to a product length, and the large bulge portion, the small bulge portion, and the rod portion are respective constituent elements. A closed forging device for forming a material into a connecting rod shape by allowing a punch to enter from the outside under a state in which a preformed body formed by plastic working is clamped by a plurality of split dies, the volume distribution corresponding to A relatively displaceable upper die and a lower die, the upper die having an upper die and a punch displacing under the guiding action of a hole formed in the upper die, The lower die is a die case that comes into contact with the upper die,
A first to fourth split dies that are displaced toward each other toward the center under the guiding action of an inclined surface formed on the inner wall of the die case; Is provided with a ridge that presses the rod of the preform to form an H-shaped cross section, and a cylindrical bulge that pierces a small bulge of the preform. The first part is brought into contact with the die case.
~ By clamping the fourth split die, the rod portion of the preform is press-formed to have an H-shaped cross-section through the ridges, and the small expansion of the preform is performed through the cylindrical bulging portion. The present invention is characterized in that a through hole is formed in the projecting portion, and the large bulging portion of the preform is upset while the punch is displaced.

[Embodiment] Next, a preferred embodiment of the closed forging device for a connecting rod according to the present invention will be described in detail below with reference to the accompanying drawings.

In FIG. 2, reference numeral 10 indicates a closed forging device according to the present invention. That is, the closed forging device 10 is basically composed of an upper mold 12 that can be raised and lowered and a fixed lower mold 14.

First, the upper mold 12 is a ram 16 connected to a hydraulic cushion.
And an upper die 22 disposed at the tip of the ram 16, and an upper die punch 22 mounted via a holder 20 that is independent of the ram 16 and is integral with the upper die body 19, and Upper die punch 22
Is inserted into a hole 24 formed in the center of the upper die 18.
The shape of the tip of the upper die punch 22 is determined according to the shape of the large end of the connecting rod material to be forged, and in this case, the protrusion 22a is formed to correspond to the semicircular hole of the large end. It

Next, the lower mold 14 is attached to the lower mold base 26 and the lower mold base 26.
And a plurality of cushion means 30 for supporting a part of the lower die 28.

First, a hole 32 extending in the vertical direction is formed in the center of the lower die base 26, and a knockout pin 34 is formed in the hole 32.
Is inserted. The knockout pin 34 can be displaced in the vertical direction by a drive source (not shown). The lower die
28 is four division dies 38a to 38d and these division dies 38
It comprises a die case 40 inside which a to 38d are displaced and which displaces them in a direction approaching each other, and the back surface of the die case 40 is restricted by a housing 42. The cushion means 30 is composed of a coil spring 43 and a rod 44 that abuts against the bottom surface of the die case 40 and supports the coil spring 43 under the resilient action of the coil spring 43.

Next, FIG. 3 shows a detailed structure of the split dies 38a to 38d and the die case 40. That is, inclined surfaces 46a to 46d each having a diameter increasing downward are formed on the rear rear surface of each of the split dies 38a to 38d. Inside the die case 40 that slides along the inclined surfaces 46a to 46d, inclined surfaces 48a to 48d that similarly expand in the downward direction are formed corresponding to the split dies 38a to 38d, respectively. Then, guide portions 49a to 49d are formed on each of the split dies 38a to 38d so as to project to both sides thereof along the inclined surfaces 46a to 46d,
Correspondingly, guide grooves 50a to 50d, into which the guide portions 49a to 49d are slidably fitted, are defined on both sides of the inclined surfaces 48a to 48d of the die case 40, respectively.

As can be seen from FIG. 2, the upper die 18 of the tip of the ram 16 that descends integrally with the upper die body 19 as the upper die 12 descends.
When the die case 40 is pressed downward, the die case 40
The rear side of the split die 38a is regulated by the housing 42.
To 38d while being guided by the guide portions 49a to 49d formed, the inclined surfaces 48a to 48d inside the die case 40 and the inclined surfaces 16a to 46d at the rear rear of the split dies 38a to 38d are slidably brought into contact with each other. The split dies 38a to 38d are configured to be displaced toward each other in the horizontal direction.

On the other hand, the facing surfaces of the split dies 38a to 38d are formed so as to correspond to the shape of the connecting rod material. In this case, the split dies 38b, 3 that form the front and rear surfaces of the connecting rod material.
8d is provided with a ridge 52 for machining the rod portion of the connecting rod material in an H-shaped cross-section, and a cylindrical bulging portion 54 for punching out the hole at the small end of the connecting rod material. In addition,
The split dies 38a and 38c are for molding the side surface of the connecting rod material, and particularly have a shape corresponding to the curved surface from the large end portion of the connecting rod material to the connecting rod portion.

The closed forging device according to the present embodiment is basically configured as described above. Next, a closed forging method for a connecting rod material using this closed forging device will be described below.

FIG. 4 is a diagram showing changes in the shape of the molded product in the closed forging method.

In the figure, reference numeral 60 indicates a round bar-shaped billet as a material, and reference numeral 62 indicates a preformed body of connecting rod. The preform 62 has a shape having a relatively small small bulge portion 64 formed on one end side and a large bulge portion 66 on the other end side, and the small bulge portion 64 and the large bulge portion 66 are provided. Between the rods
68 is formed.

On the other hand, reference numeral 70 is a connecting rod material before finishing, which is obtained as a result of molding the preform 62 by closed forging. The connecting rod material 70 includes a small end portion 72, a large end portion 74, and a connecting rod portion 76.

Here, in the preformed body 62, the volume distribution of its constituent parts is distributed in advance to be substantially equal to the volume distribution of each constituent part of the connecting rod material 70. That is, the preform
62 is a billet in advance so that the volumes of the small bulging portion 64, the large bulging portion 66, and the rod portion 68 are equal to the small end portion 72, the large end portion 74, and the connecting rod portion 76 of the connecting rod material 70 after molding. Roughly molded from 60. Further, in this case, the length of the rod portion 68 is set equal to the length of the connecting rod portion 76 of the connecting rod material 70. In order to roughly form such a preform 62 from the billet 60, any plastic working method such as cross roll, swaging, electric upsetter, and extrusion may be used.

Therefore, the preformed body 62 is formed into the connecting rod material 70 before finishing by closing forging. As shown in FIG. 5a, the preform 62 is installed at a predetermined position between the split dies 38a to 38d.

Next, the preform 62 is subjected to drawing from a direction orthogonal to its axial direction. That is, the upper die 12 is displaced downward and the upper surface of the die case 40 that surrounds the split dies 38a to 38d is pressed via the upper die 18 provided on the ram 16, and the elastic force of the coil spring 43 is applied to this. Displace downward against. The die case 40 receives the pressing action of the upper die 18 and descends along the inclined surfaces 46a to 46d of the split dies 38a to 38d. At this time, since the rear surface of the die case 40 is regulated by the housing 42, only vertical displacement is allowed, so that the die case 40 moves downward relative to the split dies 38a to 38d as the die case 40 descends. Will have the effect of displacing the two close to each other.

Split dies 38a through 38d, as shown in FIGS.
Are displaced towards each other, which results in
The preform 62 is squeezed in a direction orthogonal to its axial direction. Then, when the upper die 18 is further lowered, the die case 40 comes into contact with the upper surface of the lower die base 26, the displacement of the split dies 38a to 38d is stopped, and the die is clamped.
Through the molding process described above, the preform 62 is molded by the split dies 38a to 38d to the small bulge portion 64 and the rod portion 68. In particular, the ridges 52 (shown by meshes in FIG. 5) formed on the split dies 38b and 38d form the rod portion 68 into an H-shaped cross section. The small bulging portion 64 has a hole punched out by the columnar bulging portion 54. As a result, the small bulge portion 64 and the rod portion 68 of the preformed body 62 are formed into the shapes of the small end portion 72 and the connecting rod portion 76 of the connecting rod material 70.

Next, following the above-mentioned molding, the up-molding to the large bulging portion 66 of the preformed body 62 is added. That is, the upper mold
When 12 is further lowered, the upper die 18 is connected to the hydraulic cushion (not shown) through the ram 16, so that the upper die 18
Even when 12 itself descends, the upper die 18 is in contact with the die case 40 and the split dies 38a to 38d and maintains the current position. On the other hand, the upper die punch 22 is fitted between the dividing dies 38a to 38d as the upper die 12 itself descends, and the large bulging portion of the preformed body 62.
Start upsetting for 66 (see Figure 5b). In this way, the large bulge portion 66 of the preform 62 is formed into a predetermined shape.

The connecting rod material 70 obtained as described above is the upper die
After 12 is lifted to open the split molds 38a to 38d, they are taken out by the knockout pin 34. Then, the connecting rod material 70 is sent to another process, where precise machining is performed to complete the connecting rod.

In this case, each component of the preformed body 62, that is, the small bulge portion 64, the rod portion 68, the large bulge portion 66, the volume distribution is made in advance corresponding to the shape after molding, and Since the length of the rod portion 68 is also set to be the same as the length after forming, it is possible to form the small bulge portion 64 and the rod portion 68 into a substantially finished shape of connecting rod.

[Effects of the Invention] As described above, according to the present invention, the preformed body in which the volume distribution of each constituent portion is preliminarily distributed corresponding to the shape after molding is squeezed by the split mold, and the punch is divided by the split mold. It is fitted into and upset molding is added. Therefore, a shape close to a finished shape can be formed, and the above steps correspond to one stroke of the single-acting press machine, so that the cycle of steps can be shortened. Therefore, for example, when the connecting rod material thus obtained is sent to the finishing step, it is not necessary to heat it again for sizing, and the effect of improving the efficiency of the step can be obtained.

Although the present invention has been described above with reference to the preferred embodiments, the present invention is not limited to these embodiments, and various improvements and design changes can be made without departing from the scope of the present invention. Of course.

[Brief description of drawings]

FIG. 1 is a perspective view showing the shape of a general connecting rod, FIG. 2 is a partially omitted sectional view showing the construction of a closed forging device according to the present invention, and FIG. 3 is used for the closed forging device in FIG. FIG. 4 is a perspective view showing a configuration of a split die and a die case, and FIG. 4 is a perspective view showing a shape of a processed product in each step in the closed forging method using the closed forging device shown in FIG. 3A to 3C are views for explaining a series of steps by the closed forging device in FIG. 2 …… Conrod, 10 …… Closed forging device 12 …… Upper mold, 14 …… Lower mold 16 …… Lamb, 18 …… Upper die 20 …… Holder, 22 …… Upper punch 28 …… Lower die , 30 …… Cushion means 38a to 38d …… Split die, 40 …… Die case 60 …… Billet, 62 …… Preform

Claims (1)

(57) [Claims] 1. A small bulge portion formed on one end side, a large bulge portion formed on the other end side, and a length substantially equal to the product length between the small bulge portion and the large bulge portion. And a large bulge portion, a small bulge portion, and a rod portion are subjected to volume distribution corresponding to respective constituent elements, and a plurality of preformed bodies formed by plastic working are formed. A closed forging device that inserts a punch from the outside under a state of being clamped by a split die to form the material into a connecting rod shape, and includes a relatively displaceable upper die and a lower die, wherein the upper die is An upper die and a punch that is displaced under the guide action of a hole formed in the upper die, the lower die includes a die case that contacts the upper die, and The 1st to 4th parts are displaced toward each other toward the center under the guiding action of the inclined surface formed on the wall surface. A die for pressing the rod portion of the preform to form an H-shaped cross section on the inner wall surfaces of the first to fourth divided dies; and a small bulge portion of the preform. Is provided with a cylindrical bulging portion, the first die under the abutting action of the upper die and the die case.
When the fourth split die is clamped, the rod portion of the preform is press-formed to have an H-shaped cross section through the protrusion, and the preform is slightly bulged through the cylindrical bulge portion. A closed forging device for a connecting rod, wherein a through hole is formed in the portion, and further, the large bulging portion of the preform is upmolded under the action of displacement of the punch.