JPS605382B2 - Cold forging forming equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus suitable for cold forging of small-diameter hollow cylindrical products mainly having a small diameter and a long hollow part.

Conventional forging equipment for cold forging small-diameter hollow cylindrical products such as pipes consists of a lower punch fixed on a base and a lower punch suspended from an elevating member facing the lower punch. an upper punch having approximately the same diameter as the lower punch;
A die having a forming hole disposed between the lower punch and the upper punch and capable of accommodating a solid cylindrical workpiece is known. The workpiece can be extruded in the forming hole using punches above and below both ends of the workpiece, thereby leaving both ends open and an unformed wall remaining in the middle, as shown in FIG. A hollow cylindrical molded product is obtained.

By the way, in the above-mentioned conventional apparatus, since the die is fixedly supported on the base, the upper and lower parts of the workpiece may Even if the area reduction rate is the same, the elongation rate of the workpiece is larger on the movable upper punch side with respect to the die and smaller on the fixed lower punch side with respect to the die.
As shown in the figure, the depth 1 of the hollow part formed by the upper punch is considerably longer than the depth 1' of the hollow part formed by the lower punch, and the depth 1' of the workpiece after forming is considerably longer than the depth 1' of the hollow part formed by the lower punch. The ratio of 1' is not fixed, and as a result, the position of the unformed wall becomes indeterminate, and in the subsequent process of punching out the wall using a punch, which is called piercing, the punching side of the workpiece is restricted to one side, making the work difficult. It was tedious and time consuming.

Therefore, in order to eliminate the drawbacks of such conventional forming methods, the upper side of the workpiece is thickened and the lower side thereof is thinned in advance, and the unformed wall portion formed on the workpiece after forming is positioned at the upper and lower center of the molded product. There was also a proposal to do this, but this did not result in a particular improvement because the thickness of the molded product would not be consistent and the subsequent grinding process would be time-consuming.

In view of the above, the present invention supports the die to be movable up and down so that the relative speed of the upper and lower punches to the die is approximately constant during extrusion molding using the upper and lower punches, thereby making it possible to extremely easily perform the extrusion molding. The purpose of the present invention is to provide a cold forging forming device with a simple configuration in which the wall portion can be positioned at the vertical center of the molded product, and its feature is that it is fixed on the base. a lower punch, an upper punch having approximately the same diameter as the lower punch and suspended from the elevating member so as to face the lower punch, and a solid cylindrical workpiece disposed between the lower punch and the upper punch. and a die having a forming hole capable of accommodating a steel plate, and when the elevating member is lowered, the workpiece is extruded in the forming hole above both ends thereof using a lower punch, so that both ends are open and the intermediate die is formed. In the cold forging forming apparatus capable of manufacturing a hollow cylindrical molded product in which a wall portion remains after being formed, the die includes a lower support spring and an upper support spring between the base and the elevating member. The spring force of the upper and lower support springs can substantially match the relative speeds of the upper and lower punches with respect to the die during extrusion molding of the workpiece. It is to be set to such a size.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. A guide post 2 is installed on one side of a base 1, and this guide post 2 has a guide hole 4 formed on one side of an elevating member 3 such as a press ram. The elevating member 3 is guided by the guide post 2 and can be moved up and down.

A columnar lower punch 5 is erected in the center of the base 1, and a die guide 6 is mounted on the base 1 surrounding the lower punch 5.
is fixed.

A die 8 is fitted in a guide hole 7 formed in the die guide 6 so as to be slidable up and down. A lower support spring 9 is interposed between the base 1 and the die 8, and the lower support spring 9 can support the die 8 in a floating manner. Inner wall of guide hole 7 and die 8
Steps 10 and 11 that can engage with each other are formed on the outer wall of the
The upward position of the die 8 is regulated by their engagement. In addition, a forming hole 12 capable of accommodating a solid cylindrical workpiece W is formed in the die 8, and the workpiece W inside this forming hole 12 is
It is supported by the lower punch 5. A punch holder 13 is suspended from the elevating member 3 directly above the die 8, and a columnar upper punch 14 facing the lower punch 5 is suspended from the punch holder 13.

An upper support spring 15 is inserted between the punch holder 13 and the die 8. The upper and lower support springs 15 and 9 have a spring force that allows the die 8 to be supported in a floating manner between the punch holder 13 and the base 1, and their spring force is The size is set such that the relative speeds of the upper and lower punches 14 and 5 with respect to the die 8 can be approximately matched during molding of the workpiece W being lowered by the elevating member 3.

Next, the operation of one embodiment of the present invention will be described. Now, the lifting member 3 is raised and the upper punch 14 is raised together with the punch holder 13.

In this state, the die 8 is supported in a floating manner where the elastic forces of the upper and lower support springs 15 and 9 are balanced. Next, a solid cylindrical workpiece W is inserted into the forming hole 12 of the die 8 and supported on the lower punch 5. If the elevating member 3 is lowered here, the upper punch 14 is lowered, and the lower end of the upper punch 3 is supported against the upper surface of the workpiece W as shown in FIG. When the upper punch 14 is further lowered due to the continued lowering of the lifting section 3, the workpiece W is moved to the upper and lower punches 14, 5.
When the upper punch 14 is lowered to the lowest position as shown in FIG. 2, the solid cylindrical workpiece W can be formed into a hollow cylindrical body having a cross-sectional shape. By the way, when forming this workpiece W, the spring forces of the upper and lower support springs 15 and 9 are set so that the relative speeds of the upper and lower punches 14 and 5 with respect to the die 8 are approximately the same.
can be stretched approximately equally vertically, and as a result, the third
As shown in the figure, the molded workpiece W has a molded wall portion formed in the upper and lower center portions thereof, so that the above-mentioned 1 and 1' can be made substantially equal. Note that the position of the unformed wall portion of the workpiece W can be changed by adjusting the relative strength of the spring forces of the upper and lower support springs 15 and 9.

As described above, according to the present invention, there is a lower punch fixed on a base, an upper punch that is suspended in the elevator section opposite to the lower punch and has approximately the same diameter as the lower punch, and The die is disposed between a lower punch and an upper punch and has a forming hole capable of accommodating a solid cylindrical workpiece. In a cold forging forming apparatus capable of manufacturing a hollow cylindrical molded product with both ends open and an unformed wall remaining in the middle part by extrusion molding using punches above and below both ends, the die is , is supported in a floating manner and movable up and down between the base and the lifting part via a lower support spring and an upper support spring, respectively, and the spring force of the upper and lower support springs is applied to the extrusion of the workpiece. The sizes are set so that the relative speeds of the upper and lower punches to the die can be approximately matched during molding, so that when the upper punch descends during molding, the upper and lower support springs perform compression molding according to the amount of descent. By balancing their elastic forces with each other, the relative speeds of the upper and lower punches relative to the die can be approximately matched, and this allows the workpiece to be moved above and below the center of the die. As a result, the formed workpiece can be formed with a wall section in the center in the vertical direction, and then in the piercing process for punching out the wall section, the workpiece is stretched at both ends. Directional punching can be performed from either side, and the wall thickness of the molded product remains constant, so the machining allowance for the subsequent finishing process is reduced, and the overall accuracy is high. This makes it possible to obtain molded products suitable for mass production.

[Brief explanation of drawings]

1 and 2 are sectional side views of the apparatus of the present invention, with FIG. 1 showing the state immediately before forming the workpiece, and FIG. 2 showing the state after forming the workpiece. FIG. 3 is a longitudinal sectional view of a workpiece formed by the apparatus of the present invention, and FIG. 4 is a longitudinal sectional view of a workpiece formed by the conventional apparatus. 1... Base, 3... Lifting member, 5
...Lower punch, 8...Die, 9...
...Lower support spring, 12...Molding hole, 14
...Top punch, 15...Top support spring. Figure 1 Figure 2 Figure 3 Longevity diagram

Claims (1)

[Claims] 1. A lower punch 5 fixed on the base 1, an upper punch 14 having approximately the same diameter as the lower punch 5 and suspended from the elevating member 3 facing the lower punch 5, and the lower punch 5.
and a die 8 having a forming hole 12 disposed between the upper punch 14 and capable of fitting and accommodating a solid cylindrical workpiece W, and when the elevating member 3 is lowered, the workpiece is Above both ends of W, lower punch 1
4 and 5 to produce a hollow cylindrical molded product with both ends open and an unformed wall remaining in the middle, the die 8 includes:
The base 1 and the elevating member 3 are supported in a floating manner and movably up and down via a lower support spring 9 and an upper support spring 15, respectively, and the spring force of the upper and lower support springs 15, 9 is as follows: A cold forging forming apparatus characterized in that the size is set such that the relative speeds of the upper and lower punches 14 and 5 with respect to the die 8 can be substantially matched during the extrusion molding of the workpiece W.