JPH06179032A - Closed die forging device - Google Patents

Abstract

PURPOSE:To form with forging a material being easy to be cracked with forging without generating a forging crack. CONSTITUTION:A roughly shaped material W having an outer shape of a slightly smaller outer shape than a forging article is set inside a die 11, a material flow which is generated by pressurizing with fixed lower punches 13, 14 and fixed upper punches 23, 25 to a thickness direction is pressed with moving lower punches 16, 17 and moving upper punches 26, 27 supported with cushions 21, 22, and the generation of a tensile stress on a surface of material is controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hermetic forging apparatus used for hermetic forging, and more particularly to a hermetic forging apparatus suitable for forging a material which is likely to cause forging cracks.

[0002]

2. Description of the Related Art Forging materials made of rapidly solidified aluminum powder, for example, are known to easily crack when forged. Conventionally, as a countermeasure against this forging crack, for example, in Japanese Unexamined Patent Publication No. 3-23027, as shown in FIG. 8, a rough shaped material 1 obtained by cutting a profile extruded material made of a rapidly solidified aluminum powder is used. And a frame material 2 obtained by cutting an extruded material of an aluminum material having good spreadability, and inserting the rough shaped material 1 into the hollow portion 2a of the frame material 2 and placing it in a semi-hermetic forging die. A technique has been proposed in which the burr is removed by trimming after the frame member 2 is set and forged to be discharged as a burr. According to this technique, since the material flow in the lateral direction (width or length direction) of the rough material 1 is suppressed by the frame material 2 during forging, the tensile stress that tends to occur on the surface is reduced, and forging cracks occur. Will be prevented.

[0003]

However, according to the technique described in the above publication, the frame material 2 is also forged together with the rough shape material 1 and becomes disposable, so do not prepare as many as forged products. However, there is a problem in that the manufacturing process requires extra man-hours and costs, and a large increase in manufacturing cost cannot be avoided.

The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to prevent the occurrence of forging cracks without using an extra material such as a frame material. To provide a closed forging device.

[0005]

In order to achieve the above object, the present invention provides a lower punch inside a die, and
Closed forging in which an upper punch is arranged in the upper mold so as to face the lower punch, and a rough material having an outer shape slightly smaller than the outer shape of a forged product set in the die is pressed by the lower and upper punches. In the apparatus, each of the lower punch and the upper punch is formed of a fixed punch forging a relatively thin portion and a movable punch forging a relatively thick portion, and the movable punch is It is characterized in that it is supported by a cushion that generates a biasing force in the forging direction.

[0006]

In the closed forging device configured as described above, since the gap between the inner surface of the die and the outer periphery of the rough material is small, the material flow in the lateral direction of the rough material is restricted immediately after the start of forging. Causes a material flow in the thickness direction, and at this time, the cushioning force is applied to the movable punch, so a compressive force is applied to the material flowing in the thickness direction from the movable punch, and this compressive force causes the surface of the material to move. The occurrence of tensile stress in the steel is suppressed, and forging cracks are less likely to occur.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A closed forging device according to the present invention will be described below with reference to the accompanying drawings.

1 and 2, reference numeral 11 denotes a die having a through hole 11a corresponding to the outer shape of a forged product, which is fixed on a bolster (not shown) via a spacer block (not shown). Also, the through hole of the die 11 is provided on the bolster.
Punch holder 12 having a recess 12a at a position corresponding to 11a
Are fixed, and three fixed lower punches 13, 14, 15 and two movable lower punches 16, 17 are arranged in the recess 12a. These punches are positioned so that the tip end faces the through hole 11a of the die 11, and especially the movable lower punch.
16 and 17 are slidable with respect to the die 11 and the fixed lower punches 13, 14, and 15. The forged product to be obtained in this example is a connecting rod which is one of automobile parts, and the three fixed lower punches 13, 14 and 15 are for large end hole forming, small end hole forming and column forming, respectively. On the other hand, the two lower movable punches 16 and 17 are used for forming the large end and forming the small end, respectively.

The two movable lower punches 16 and 17 have flange portions 16a and 17a on the outer periphery of their lower ends which are in sliding contact with the die 11, and the flange portions 16a and 17a are provided at the bottom of the recess 12a of the punch holder 12. It is fitted in 18. The height of the groove 18 is 16 for each brim.
It is set so as to be larger than the thickness of a and 17a by a predetermined distance δ, whereby two movable lower punches 16 and 17 are provided.
Can slide in the vertical direction within the range of the distance δ. Further, the two movable lower punches 16 and 17 are respectively supported by cushions (compression springs in this case) 21 and 22 housed in recessed holes 19 and 20 formed in the bottom surface of the recess 12a of the punch holder 12, and are normally provided with brims. Grooves 16a, 17a on the groove of the punch holder 12
It is lifted at the rising end that abuts the upper surface of 18. Among these lower punches, the fixed lower punch 13 for forming the large end hole and the fixed lower punch 14 for forming the small end hole are the longest, and the movable lower punch 16 for forming the large end portion and the small end portion, 17 is the shortest, and the respective lengths are set so that the lower fixed column punch 15 for forming a column has an intermediate length between the former two.

On the other hand, an upper die (not shown) arranged above the die 11 and vertically moving integrally with a press ram (not shown) is also provided with upper punches in the same manner as the above lower punches. There is. These upper punches are three fixed upper punches 23, 2
4 and 25 and two movable upper punches 26 and 27, which are fixed lower punches 13, 14 and 15 and movable lower punches 16 and 17, respectively.
It is arranged corresponding to.

Thus, the rough shape material used in the present embodiment is obtained by cutting a profile extruded material of a material using rapidly solidified aluminum powder, and as shown in FIGS.
The rough material W is formed to have an outer shape slightly smaller than the outer shape of the connecting rod P which is a forged product, and the large end portion Pa of the connecting rod P is formed.
Further, it is formed to have a thickness smaller than that of the small end portion Pb and larger than that of the column Pc.

The operation of the hermetic forging device configured as described above will be described below with reference to FIGS.

At the time of forging, first, the upper die (not shown) is lifted up to insert the coarse shaped material W into the through hole 11a of the die 11 and, as shown in FIG. The rough material W is placed on top. Next, the upper die is moved downward together with a press ram (not shown). Then, the fixed upper punches 23, 24 first come into contact with the upper surface of the rough material W, and the lower and upper fixed punches 13, 14 are made.
The rough material W is compressed between 23 and 24, and the rough material W causes material flow in the lateral direction. However, since the gap between the inner surface of the through hole 11a of the die 11 and the outer periphery of the rough material W is small,
Immediately after the start of forging, the die 11 restricts the lateral material flow by the die 11. As a result, as shown in FIG. 6, the rough-shaped material W has the movable lower punches 16, 17 and the movable upper punches 26,
Material flow occurs in the area facing 27, that is, in the thickness direction, and contacts the end faces of these movable punches. At this time, the lower and upper movable punches 16, 17 and 26, 27, respectively,
A predetermined biasing force (cushion pressure) is applied from the cushions 21 and 22, whereby a compressive force is applied from the movable punch to the material flowing in the thickness direction.

Thereafter, in response to the lowering of the upper die, the lower and upper movable punches 16, 17 and 26, 27 are respectively cushioned.
Although it retreats against the urging force of 21, 22, during this time, a compressive force is continuously applied to the material from these punches, and as a result, the compressive force suppresses the occurrence of tensile stress on the material surface, and forging The occurrence of cracks is prevented. And
Eventually, each of the lower and upper movable punches 16, 17 and 26, 27 reaches the retracted end, the material is filled up in the facing area of these movable punches as shown in FIG. 7, and the forging is completed. Material flow also occurs in the opposing regions of the column forming fixed punches 15 and 25, but since the step between these and the large end and small end hole forming fixed punches 13, 14 and 23, 24 is not so large, this The tensile stress generated on the surface of the material flowing in the region is not so large, so that forging crack does not occur in this region.

In the above embodiment, the compression springs are used as the cushions 21 and 22, but the type of the cushion is arbitrary, and for example, a cylinder device can be used. Further, in the above embodiment, the material made of the rapidly solidified aluminum powder was targeted, but the kind of the targeted material is arbitrary, and it goes without saying that a material other than aluminum can be targeted. Further, as the rough shaped material W, other materials such as an upsetter material may be used instead of the deformed extruded material in the above embodiment. Further, it goes without saying that the product target may be another component instead of the connecting rod in the above embodiment.

[0016]

As described above in detail, according to the closed forging device according to the present invention, the cushion pressure is applied to the material during the forging process, so that the excess material such as the frame material can be removed. It is possible to prevent the occurrence of forging cracks without using it, and there is an effect that the manufacturing cost can be reduced.
Further, since the closed forging is performed, it is not necessary to remove the burrs afterward, which greatly contributes to the improvement of productivity.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the structure of a closed forging device according to the present invention.

FIG. 2 is a plan view taken along the line AA of FIG.

FIG. 3 is a plan view showing the shape of a rough material used in the closed forging device.

FIG. 4 is a front view showing the shape of a crude material used in the main closed forging.

FIG. 5 is a cross-sectional view showing a usage mode of the present closed forging device.

FIG. 6 is a cross-sectional view showing a mode of use of the present closed forging device.

FIG. 7 is a front view showing the shape of a crude material used in the main closed forging.

FIG. 8 is a perspective view illustrating a conventional forging method.

[Explanation of symbols]

 11 die 12 punch holder 13 fixed lower punch 14 fixed lower punch 15 fixed lower punch 16 movable lower punch 17 movable lower punch 21 cushion 22 cushion 23 fixed upper punch 24 fixed upper punch 25 fixed upper punch 26 movable upper punch 27 movable upper punch W coarse Profile P Forged product

Claims (1)

[Claims] 1. A lower punch is disposed inside a die, and an upper punch is disposed in an upper mold so as to face the lower punch.
In a closed forging device that presses a rough shape material having an outer shape slightly smaller than the outer shape of a forged product set in the die by the lower and upper punches, each of the lower punch and the upper punch is relatively thin-walled. Is formed from a fixed punch that forges-forms a portion that becomes and a movable punch that forges-forms a relatively thick portion, and the movable punch,
A closed forging device characterized by being supported by a cushion that generates a biasing force in the forging direction.