JPH069725B2 - Molding method for stove - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for forming a connecting rod made of a difficult-to-form material such as an Al powder material or a Ti alloy, and more particularly to forming from a preform product.

(Prior art) Conventionally, connecting rods have been conventionally hot-rolled or hot-pressed or hammered into a preformed product that has been appropriately volume-distributed according to the shape of the product by hot cross-roll forming. Upsetting die-casting was performed by simply crushing with the upper die while producing a lot of burrs (or flashes).

(Problems to be solved by the invention) Recently, in order to reduce the weight and improve fuel efficiency and performance, A
l High-strength materials such as powder-based composite materials and Ti alloys, or high-grade materials that are difficult to mold are substituted, but these materials have poor ductility and the temperature range in which molding is possible is extremely narrow. There is a limit when applied as it is.

For example, if the number of processes is large, there is a problem that elongation of work decreases due to temperature decrease during that time, and tensile stress acts on the outer circumference of the work at the time of upsetting. It becomes a defect. In addition, since a large burr is required to form a shape in every corner without any deficiency, the yield is poor and expensive materials are wasted.

Therefore, it is desired to perform burr-free closed forging, and for that purpose, a preform product appropriately distributed in volume corresponding to the large end and the small end of the connecting rod product is required. Further, it is advantageous for burr-free closed forging that the large end and the small end of the briform product have a short length and a large thickness, that is, a spherical shape is more convenient.

However, in the preforming by the forward extrusion from the large-diameter billet, there are problems that the drawing ratio is large and it is easily cracked, and that it is particularly difficult to bulge the small end portion.

Also, when the large end is molded integrally, it must be separated later, so it is common to make the connecting rod body and the cap that corresponds to the large end half separately, and the product shape of the large end is bifurcated. However, if you simply crush it, the material at the center of the large end will be sheared by the mold, burrs will be removed, and the preform product will not fit in the mold easily. There are also problems such as difficulty in making reformed products.

(Means for Solving the Problems) In order to address the above problems, the present invention is directed to a large and small end portion of a rod material corresponding to a connecting rod connecting the large end portion and the small end portion of a connecting rod with electric upsetters. The preform product (1) having the spherical parts (2) and (3) is formed, and the preform product (1)
Is charged into the upper and lower molds (11) and (21) to close the mold, and then the side punch (51) is pressed into the larger spherical portion (2) to form a bifurcated shape, and then the Upper and lower punches (31) having the product shape while being constrained in a bifurcated shape by the side punches (51),
At (41), the preform product (1) is double-pressed to be crushed and molded.

(Function) Since the spherical parts (2) and (3) at both ends of the small diameter rod material corresponding to the connecting rod connecting part are molded by the electric upsetter, the drawing process is unnecessary and cracks do not occur even with difficult-to-mold materials. ,
Optimal volume distribution is possible. Moreover, since an electric upsetter is used, there is no need to heat the entire preform, and no complicated steps are required.
Preform product (1) is molded into molds (11) and (21) by molding (2) and (3).
It can fit in well.

Also, before punching the preform product (1), the side punch (51)
Is retracted, the material can be charged without interfering with it, and the material is not sheared.

When the preform product (1) is closed in the molds (11) and (21), the side punch (51) first enters and pressurizes, and then the upper and lower punches (31) and (41) apply double-acting pressure. Since the product (6) is molded by the above method, the connecting rod product (6) is free from burrs and can be subjected to burr-free closed forging.

Furthermore, since the upper and lower punches (31), (41) are double-action moldings in which both are moved and pressed, how to fill the material on the upper and lower sides of the product,
That is, since the filling degree is uniform and no undue force is required, the accuracy is good, the load is low, and the load on the mold is small.

(Examples) Examples will be described below with reference to the accompanying drawings.

Figures 1 and 2 show before pre-molding, (1) is a preform product, (11) is an upper die, (21) is a lower die, (31) is an upper punch, and (41) is a lower die. The punch (51) is a side punch, and the preform product (1) is preformed in the previous step from a round bar material made of, for example, an Al powder type composite material.

That is, spherical parts of different sizes are attached to both ends of a rod material of a small diameter corresponding to the connecting rod connecting portion by electric upsetters (not shown).
(2) and (3) are formed, and the large and small spherical portions (2) and (3) have an optimal volume distribution corresponding to the connecting rod large end portion and the connecting rod small end portion, respectively.

On the other hand, the upper mold (11) and the lower mold (21) have large mold ends (12), (22) and small mold end (1) according to the shape of the connecting rod to be molded.
3), (23) and die connecting rods (14), (24) are continuously formed in the vertical direction, and double-action press devices (not shown) are formed in the through holes (15), (25). The upper punch (31) and the lower punch (41), which are operated by, are vertically slidably assembled. Also, the large end (1
Guide holes (16) and (26) are continuously formed at the ends of the mold connecting rods (14) and (24) facing the mold connecting holes (14) and (23). The side punch (51) is assembled so that it can slide back and forth. The tip of the side punch (51) is provided with a semi-circular protrusion (52) for forming the connecting rod large end into a bifurcated shape.

Then, the preform product (1) is formed by the electric upsetter as described above, and then the whole preform is heated to form the preform product (1) between the upper mold (11) and the lower mold (21). ) Is set and the mold is closed, first, as shown in FIG. 3, the side punch (51) is moved forward with respect to the large ends (13) and (23) of the mold. When the semi-circular protrusion (52) of the side punch (51) is pressed in, the larger spherical portion (2) begins to form a bifurcated shape as shown.

Then, as shown in FIG. 4, the side punches (51) are advanced and held with respect to the large end portions (13) and (23) of the die, and as shown in FIG.
1) and (41) are double-moved, and the preform product (1) is double-action pressed from above and below to be crushed and molded, and the forging finish molding is completed.

Thus, the conrod product (6) is obtained by hermetically forging from the preform product (1), and this product (6) has a shaft hole formed in its small end in the next step.

(Effects of the Invention) As described above, according to the present invention, forging finish molding is performed from a preform product in which large and small spherical parts are formed at both ends of a small diameter rod material by an electric upsetter, and a side punch is pressure-applied. Since the connecting rod product is obtained by double-acting pressing with the upper and lower punches, it is possible to prevent cracking defects of the connecting rod made of difficult-to-form material and to rationally and accurately perform the flash-free closed forging, and to make the material filling uniform. To increase strength,
It also contributes to the improvement of mold life.

[Brief description of drawings]

1 and 2 are a vertical cross-sectional view and a plan view of the die, FIG. 3 is a plan view showing a pressure punch of a side punch, and FIG. 4 is a vertical cross-sectional view showing a double-action press of upper and lower punches. Is. In the drawings, (1) is a preform product, (2) and (3) are spherical parts,
(6) is a product, (11) and (21) are molds, (31) is an upper punch, (41) is a lower punch, (51) is a side punch, and (52) is a semi-circular protrusion.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-56-128636 (JP, A) JP-A-56-128637 (JP, A)

Claims (1)

[Claims] 1. A preform product having large and small spherical parts at both ends is formed by an electric upsetter from a bar material corresponding to a connecting rod part connecting a large end part and a small end part of a connecting rod. Is closed into the upper and lower molds, the side punch is pressed into the larger spherical portion to form a bifurcated shape, and then the product shape is obtained while the bifurcated shape is constrained by the side punch. A method for forming a connecting rod, characterized in that the preform product is double-action pressed and crushed and formed by upper and lower punches.