JPS585128B2 - Cutting device for forged products in rotary forging machines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cutting device for a forged product in a rotary forging machine, and more particularly to a cutting device used for cutting an end portion and a middle portion of a forging product.

Rotary forging (rolling) involves moving a pair of flat plate molds or two or three roll-shaped molds relative to each other. This is a method of processing the material passing through it by plastic deformation.

After the material is deformed into a desired shape by the action of the wedge-shaped convex portion, it is cut by a cutting device in the final step.

This cutting means, for example, cutting off unnecessary portions at both ends of the forged product, or cutting off the forged product in the middle of its longitudinal direction.

Cutting a forged product midway is done to improve productivity and to obtain forged products with symmetrical shapes at the same time. are forged at the same time and separated in the final process.

Also, in the case of rotary forging of bars, one long forged bar is separated in the final process to form multiple bars.

For such cutting, blades are provided on the faces of the opposing molds that protrude toward each other as they move relative to each other.

These blades gradually penetrate the forged product and cut the forged product in a scissoring manner.

In rotary forging, symmetrical forgings and symmetrical rotary forging dies are desired in order to obtain force balance and to give the forging as stable processing conditions as possible.

In the case of asymmetrical materials or forgings, an attempt is made to select a corresponding combination of angles in order to balance the forces.

The same problem arises for the first stage process as well.

This is because during cutting at the end of rotary forging, the final shape and dimensions are given to the forged product at the same time, which is usually called calibration, so in order to obtain a stable rotary forging process and to achieve accurate forging with small processing errors. This is because force balance is absolutely required to obtain the shape of the product.

However, there is a problem in that the quality of the cut surface at the end of the cutting process is difficult to obtain.

In other words, when the cutting distance of the cutting blade to the center plane of the forged product decreases due to wear and tear of the cutting blade, some material remains at the rotation axis of the forged product, and this remaining material is discarded as scrap. Since it is removed from the guiding action of the mold, it deforms into a hook-like shape due to its own weight.

This is a decisive drawback since it is not possible to form a punch hole for centering in the forged product, which means that additional pre-machining must be performed before centering.

Furthermore, when a forged product after rotary forging is subjected to forging without flashing as a post-processing, the protruding remaining portion of the material is left in a bent and crushed state on the surface of the forged product.

On the other hand, there is the disadvantage that small pieces of waste are not always separated reliably and often stick to the forging.

In that case, this crumb must be separated by additional processing or removed by additional processing with a rotary forging die.

However, this procedure has a detrimental effect on the guidance of the forging due to the instantaneous impact separation and has an unfavorable effect on safe waste removal.

In view of the above points, an object of the present invention is to ensure good quality of the cut surface in a forging cutting device for a rotary forging machine.
The aim is to avoid the formation of protrusions, especially in the center of the cutting point, to ensure an improved quality of the cutting surface and to make reliable cutting possible.

According to the present invention, the above-mentioned object is achieved by providing the cutting end edges of the pair of cutting blades that are closest to each other at positions separated by a distance between the molds and the mold intermediate imaginary plane passing through the rotation axis. achieved.

A feature of the present invention is that immediately before the end of the rotary forging process or the cutting process, the axial center of the forged product and the surface between the cutting end portions of the pair of cutting blades are prevented from overlapping.

In the present invention, the molds are not made to have exactly the same configuration in order to obtain symmetrical acting forces.

However, in order to reduce the associated drawbacks, the symmetry should be maintained as accurately as possible for as long as possible, and should only disappear at the end of the rotary forging process, when the forces acting on the forging are very small. Make it.

For this reason, the negative impact on forged products is extremely small.
Moreover, this is eliminated by guiding the forged product through the die.

With this configuration, one of the cutting blades always passes through the axis of the forging, resulting in problem-free cutting.

According to the configuration of the present invention, the cutting speed does not become zero even at the axis of the forged product, but rather, due to the overlap of the relative rotation and translational motion between the forged product and the die, the wedge slope of the cutting blade corresponds to the feed motion. In connection with this, the cutting conditions are significantly improved.

The present invention will be described below based on embodiments shown in the drawings.

FIG. 5 shows the principle of a rotary forging machine using a flat plate die.

A material 1 to be rotary forged undergoes rolling between a pair of parallel flat plate molds 2 and 3 that are moved in opposite directions as shown by the arrows.

At this time, the wedge-shaped protrusions 2a and 3 provided on the opposing surface of the mold 2.3
The material 1 is plastically worked under the action of a.

The ends of the wedge-shaped convex portions 2a and 3a serve as calibration portions for adjusting the final dimensions and shape of the forged product without performing substantial plastic deformation.

In this way, the forging passing through the calibration section is cut by the cutting blades 4, 5 at the end of the process.

The above-described rotary forging process is a known one, and after the forged product 1 has been given its final size and shape as shown in FIG. 1, the excess portions 10 at both ends are separated by a cutting blade 4.5.

Further, in some cases, the forged product 1 is divided at a predetermined position in the longitudinal direction by a cutting blade (not shown).

In conventional cutting devices, the cutting blades 4, 5 are symmetrically formed.

This is to balance the forces acting during the rotary forging process and perform accurate rotary forging in a stable state.Therefore, not only the wedge-shaped protrusions 2a and 3a but also the cutting blades 4 and 5 of the forged product. are equidistant at each moment with respect to the mold intermediate virtual plane passing through the rotation axis.

According to the invention, the cutting blades 4, 5 do not have a symmetrical arrangement and shape, but an asymmetrical arrangement and shape.

An example of this is shown in Fig. 2, of the cutting blades 4.5 that act at the end of the rotary forging process, the cutting end edge of one of the cutting blades 4 is a plane passing through the rotational axis of the forged product, that is, the rotational forging process. It protrudes beyond the forging mold intermediate imaginary surface (downward in the figure), and correspondingly, the cutting end edge portion of the other cutting blade 5 ends without reaching the mold intermediate imaginary surface.

Therefore, during rotational forging using the wedge-shaped convex portions 2a and 3a, stable forging work is performed under a symmetrical state, and when carburation is performed in the final process and accurate forging dimensions and shape are obtained, the asymmetrical cutting blade A cut by 4,5 is made.

By providing the asymmetrical cutting blades 4, 5, the cutting speed does not reach zero even in the forging axis as in the known case, and the forging 1 remains relative to the cutting blade 45 in all cross sections. Since the cutting speed is high, the above-mentioned problems are solved and a high-quality cut surface can be obtained.

FIGS. 3 and 4 show other examples to which the principles of the invention are applied.

In this example, the cutting blades 8 and 9 belonging to the dies 6 and 7 are the same and symmetrical, but due to the difference in thickness of the dies 6 and 7, the cutting blades 8 and 9 are different from each other in the forged product 1. The cutting section of the machine is eccentrically guided and cut.

That is, in this example as well, the cutting end edge portions of the pair of cutting blades are located at a position offset from the die intermediate imaginary plane passing through the axis of the forged product.

FIG. 6 shows the principle of known cylindrical rotary forging.

In this case, the material 1 is rotary forged between a pair of roll-shaped molds 2 and 3, but the principles of the present invention can also be applied to this type of rotary forging machine.

As described above, according to the present invention, a high-quality cut surface without protrusions can be formed in a rotary forged product.

[Brief explanation of the drawing]

Fig. 1 is a front view of a cutting device according to the present invention having an asymmetrical cutting blade, Fig. 2 is a sectional view taken along the line FIG. 4 is a cross-sectional view taken along the line ■-■ in FIG. 3, FIG. 5 is a principle diagram of a rotary forging machine, and FIG. 6 is a ground-type rotary forging machine. FIG. 1...Material (forged product), 2, 3, 6, 7...
... Mold, 4, 5, 8, 9... Cutting blade.

Claims (1)

[Claims] 1. In a cutting device for a forged product in a rotary forging machine, in which a material cutting blade is provided in the calibration area of a rotary forging convex portion provided on an opposing die, the closest cutting end edge of a pair of cutting blades is used. A cutting device characterized in that the cutting device is provided at a distance between the dies and the imaginary plane between the dies passing through the rotational axis of a forged product subjected to rotational forging between the dies.