JPH0510985Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Purpose of the invention] (Industrial application field) The invention relates to a punching mold, and more specifically, the invention relates to a punching mold, and more specifically, the invention relates to a punching mold that punches a hole on both sides of the hole at the same time as drilling a hole to form a female thread. This invention relates to a punching die that can perform chamfering.

(Prior Art) Conventionally, after punching a plate-shaped workpiece using a turret punch press, it has been possible to form a female thread in the workpiece using a tapping unit provided in the turret punch press. be. In this case, a rolling tap may be used to avoid the generation of chips.

However, when a rolling tap is used, a bulging phenomenon occurs in which the material moves due to rolling and a bulge is created at both ends of the opening of the pilot hole. Cracks may occur or the nameplate may become unstable.

Therefore, in order to prevent the occurrence of the build-up phenomenon, after drilling a pilot hole in the workpiece, a double-sided chamfer is formed with a truncated conical chamfered part corresponding to the lower end surface of the punch and the upper end surface of the die. Chamfered portions were formed at both ends of the opening of the prepared hole by the clamping pressure of the mold.

(Problem to be solved by the invention) However, when chamfers are formed at both end openings of the pilot hole using the double-sided chamfered mold described above, the material moves to the inner peripheral surface of the pilot hole when the mold is compressed. Then, even if a female thread is formed with a rolling tap, the raised part remains, resulting in a poor finish on the female thread.

In other words, a raised portion is formed on the inner peripheral surface of the prepared hole,
There was a problem in that the prepared hole had a poor shape.

In addition, since two steps are required to form the chamfer after preparing the pilot hole, there is also the problem of poor productivity.

Therefore, the present invention provides a punching die that does not affect the shape of the prepared hole even if a chamfered portion is formed, and that can process the prepared hole and form the chamfered portion in one step.

[Structure of the invention] (Means for solving the problems) In view of the conventional problems as mentioned above, the present invention has the following features:
A punching mold comprising a punch and a die for punching a plate-shaped work is used, and the tip of the shaft part of the punch is engaged with and detached from the center hole of a cylindrical die chip provided to the die. A first part for machining a chamfer at one end of a prepared hole machined in a workpiece by providing a freely cylindrical prepared hole processing part protrudingly and working with the die chip and the prepared hole processing part.
A chamfered portion is formed on the root side of the pilot hole, and a second chamfered portion for machining the chamfer at the other end of the pilot hole is provided at the tip of the die tip. The chamfering part is provided with a structure in which the diameter of the prepared hole is restricted from being reduced when the prepared hole processed part is engaged with the prepared hole during chamfering by the first chamfered part.

(Embodiment) FIG. 1 is an overall view of an embodiment of the present invention, in which a punch press upper die 3 is provided on a guide member 1 so as to be movable up and down. A lower mold 7 is provided at a position corresponding to the upper mold 3 on the support base 5 below the guide member 1 .

A cylindrical punch guide 9 is provided on the guide member 1 so as to be movable up and down.

A flange 11 is formed at the upper end of the punch guide 9, and a lift spring 13 is provided between the flange 11 and the guide member 1. The lift spring 13 serves to bias the entire upper die 3 upward.

An indoor hole 21 is formed at the lower end (tip) of the punch guide 9 to guide a punch tip 19 provided at the lower end (tip) of the shaft portion 17 of the punch 15, which will be described later.

The shaft portion 17 of the punch 15 is connected to the punch guide 9.
It is provided in a cylindrical shape so as to be movable up and down, and a collar 23 is attached to the upper end. A stripper spring 29 having a spring constant larger than that of the lift spring 13 is connected between the collar 23 and the collar 11 formed on the punch guide 9 through seats 25 and 27 loosely fitted to the shaft portion 17. is provided.

A punch tip 19 is provided at the lower part of the shaft portion 17 and projects downward.

The lower end (tip) of the punch tip 19 has a work W
A cylindrical prepared hole processing portion 31 for drilling a prepared hole for tapping is provided to protrude downward. The pilot hole processing part 3
1 has a tapered first chamfered part 33 at the base.
is formed in a widening shape toward the upper end of the shaft portion 17.

The die 35 of the lower mold 7 is provided on the support stand 5, and a cylindrical die chip 39 is vertically provided on the upper surface of the disc-shaped portion 37 forming the base. The center hole 41 of the die chip 39 is formed so as to pass through the disc-shaped portion 37, into which the shaft-shaped prepared hole processing portion 31 enters. A tapered second chamfered portion 43 is formed on the outer periphery of the tip of the die tip 39 in a diverging shape toward the bottom of the die 35.

An ejector plate 45 is provided on the upper surface of the die 35.
However, the guide shaft 47 provided on the ejector plate 45
It is provided so as to be movable up and down with respect to the die 35. The upper surface of the die 35 and the ejector plate 4
Punch the ejector plate 45 between 5 and 1.
A spring 49 is provided that constantly biases the terminal 5 toward the terminal 5.

In the above configuration, as shown in FIGS. 1 and 5, the workpiece W is placed on the upper surface of the ejector plate 45.
When a downward force is applied to the collar 23 at the upper end of the punch 15, the entire upper die 3 moves downward against the lift spring 13, and the tip of the punch guide 9 hits the surface of the workpiece W. The workpiece W is held between the punch guide 9 and the ejector plate 45 (FIG. 2).

If the punch 15 is pressed again, the results shown in FIGS.
As shown in the figure, the punch 15 has a spring 49,
The stripper is moved downward in the punch guide 9 (Fig. 3) against the stripper spring 29 (Fig. 1), and the prepared hole processing portion 31 of the punch tip 19 and the die chip 3 are moved downwardly.
In cooperation with the center hole 41 of No. 9, the workpiece W is punched out to form a pilot hole Wa. At the same time, the first chamfered portion 33 of the punch tip 19 and the second chamfered portion 43 of the die tip 39 pinch both ends of the opening of the prepared hole Wa to form a chamfered portion Wb (FIG. 6). .

At this time, the escape of the material at the chamfered portion Wb is suppressed by the prepared hole processing section 31, so that the material does not bulge on the inner circumferential surface of the prepared hole Wa.

In FIGS. 3 and 6, the punching waste Wc of the workpiece W is located inside the center hole 41 of the die chip 39 and at the tip of the prepared hole machining part 31.

Thereafter, when the pressure on the collar 23 is released, the spring 49 pushes up the ejector plate 45 and the lift spring 1
3. The punch guide 9 and the bunch 15 are returned upward by the stripper spring 29 (FIG. 1), and the entire upper mold 3 returns to the state shown in FIG. 1.

According to the mold of the above embodiment, the prepared hole processing portion 31
In addition to drilling a pilot hole for the tap, a chamfer is formed at both ends of the opening of the pilot hole by the first and second chamfered parts, so that the relief of the chamfered part is removed by drilling the pilot hole. This prevents the inner circumferential surface of the pilot hole from bulging, and the shape of the pilot hole becomes more accurate. Therefore, a highly accurate internal thread can be obtained in processing using a rolling tap.

In addition, since machining of the prepared hole and formation of the chamfered portion can be performed in the same process, productivity is improved.

Note that the present invention is not limited to the above-described embodiments, but can be implemented in other forms by making appropriate design changes.

[Effects of the invention] As can be understood from the above description of the embodiments, in short, the present invention provides a punching die comprising a punch 15 and a die 35 for punching a plate-shaped workpiece W. A cylindrical prepared hole processing part 31 that can be freely engaged and detached from the center hole 41 of a cylindrical die chip 39 provided in the die 35 is provided at the tip of the shaft part 17 provided in the punch 15 so as to protrude. A first chamfering section 33 for machining a chamfer Wb on one end of the prepared hole Wa machined in the workpiece W by the cooperation of the prepared hole processing section 31 and the prepared hole processing section 31 is installed. A second chamfered portion 43 is provided at the tip of the die tip 39 for forming a chamfered portion Wb on the other end of the prepared hole Wa, and is provided on the root side of the die tip 39.
When chamfering is performed by the chamfering portion 33, the pilot hole processing portion 31 is in a state engaged with the pilot hole Wa, and the diameter of the pilot hole Wa is restricted from being reduced.

As is clear from the above configuration, in the present invention, the shaft portion 17 of the punch 15 has a cylindrical prepared hole processing portion 31 that can be freely engaged and detached from the center hole 41 of the cylindrical die tip 39 provided in the die 35. It is installed protrudingly. and the root side of the prepared hole processing portion 31;
A die tip 3 is attached to the tip of the die tip 39.
First and second chamfered parts 33 and 43 for chamfering are provided at both ends of the prepared hole Wa punched by the prepared hole processing part 9 and prepared hole processing part 31, respectively.

Furthermore, during the chamfering process by the first chamfering part 33, the diameter of the prepared hole Wa is restricted from being reduced while the prepared hole part 31 is engaged with the prepared hole Wa.

Therefore, according to the present invention, when the prepared hole Wa is formed in the plate-shaped workpiece W, chamfering is performed on both ends of the prepared hole Wa at the same time. When chamfering is performed as described above, since the cylindrical prepared hole machining section 31 of the punch 15 is engaged in the prepared hole Wa, the first and second Even if the diameter of the prepared hole Wa tends to decrease when the chamfered portions 33 and 43 are used to deform it under pressure, the diameter of the prepared hole Wa is regulated by the prepared hole processed portion 31, so that the diameter of the prepared hole Wa is reduced. There is no problem in that the accuracy of the diameter of the prepared hole Wa can be maintained.

[Brief explanation of drawings]

Fig. 1 is an overall view of the embodiment of the present invention, Figs. 2 to 4 are explanatory diagrams of the operation of a part of Fig. 1, Fig. 5 is an enlarged view of the arrowed part in Fig. 1, and Fig. 6 is an It is an enlarged view of the arrow part of FIG. 3. 15...Punch, 31...Prepared hole processing section, 33...
...First chamfered part, 35...Die, 41...
Center hole, 43...second chamfered part, W...workpiece, Wa...prepared hole, Wb...chamfered part.

Claims (1)

[Scope of utility model registration request] Punch 1 for punching a plate-shaped workpiece W
5 and a die 35, a cylindrical column is provided at the tip of the shaft portion 17 of the punch 15, which can be freely engaged with and detached from the center hole 41 of a cylindrical die tip 39 of the die 35. A pilot hole machining section 31 having a shape protruding is provided, and a chamfer Wb is machined at one end of the pilot hole Wa machined in the workpiece W by the cooperation of the die chip 39 and the pilot hole machining section 31. A chamfered part 33 of No. 1 is formed and provided on the root side of the prepared hole processed part 31, and
A second chamfered part 43 for machining a chamfered part Wb on the other end of Wa is provided at the tip of the die chip 39, and the first chamfered part 3
At the time of chamfering according to step 3, the prepared hole processing portion 31 is in a state engaged with the prepared hole Wa, and the prepared hole
A punching die characterized by having a configuration that restricts the reduction of the diameter of Wa.