JPH0852515A - Die for bending machine - Google Patents

Abstract

PURPOSE:To reduce the wear of a die and to decrease scratch on a work in a bending machine by forming radius parts having a large diameter radius part on the shoulder part of die, providing clearance grooves in the bottom parts of die and further applying nitriding treatment to a lower die. CONSTITUTION:V-bending is applied to a work W by elevating the lower die 5 cooperating with an upper die 9 when the lower table 3 is elevated after placing the work W on the upside of the lower die 5. With the progress of this V-bending, bending is executed while the underside of the work W is slid on the curved surface of the radius part 15A or 15B which is formed on the lower die 5. Because the radius parts 15A, 15B have a large radius, the work is not scratched even when the work is slipped. Because clearance grooves 17A, 17B are formed on the V-bottoms of V-dies 11A, 11B and refuse by bending which is generated at the time of bending is dropped into these clearance grooves 17A, 17B, the work is prevented from being scratching with the refuse by bending. Since, nitriding treatment is applied to the lower die 5, the die is excellent in wear resistance and corrosion resistance and rust is prevented from being generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for a bending machine, and more particularly to a mold for a bending machine which is improved as a mold to improve the life of a lower mold.

[0002]

2. Description of the Related Art Conventionally, the shape of a lower mold for bending a work in cooperation with an upper mold provided in a bending machine has a simple V-shaped or U-shaped groove. Is common.

[0003]

By the way, in the above-mentioned conventional lower die, when the work placed on the lower die is bent into a V shape, the R portion of the shoulder portion of the die formed on the lower die is formed. Since the shape is small, there is a problem that wear is quick due to the load caused by slipping of the work, especially when the stainless material and the thick plate are bent, the mold shoulder of the lower mold is rapidly worn and the life is short. There is also a problem that the work is flawed.

From the results of many experiments conducted by the inventors,
As shown in FIG. 4, the wear progress state of each time is graphed from 100 times bending to 2000 times bending from the shape of the shoulder portion (shoulder R: 0.8 mm) before the test shown by the solid line, At the end of 2000 times bending, the shoulder wear was 0.
It was found to be 3 mm.

An object of the present invention is to provide a mold for a bending machine, which is intended to improve the life of the lower mold and the bending accuracy of the work without scratching the work.

[0006]

In order to achieve the above object, a mold of a bending machine of the invention according to claim 1 is provided with an upper mold for bending a work in cooperation with a lower mold. A bending machine is used to form a large-diameter R portion on the mold shoulder formed on the lower mold with which the work slides during bending, and at the bottom of the mold formed on the lower mold. It is characterized in that an escape groove for dropping the residue is provided and the surface of the lower die is subjected to a nitriding treatment.

A mold for a bending machine according to a second aspect of the present invention is the mold for a bending machine according to the first aspect, wherein the nitriding treatment is a lower mold having a quenching and tempering hardness of HRC 40 or more. , Nitriding is performed, and the nitriding treatment smoothes the hardness difference between the nitriding surface hardness and the mold internal hardness,
It is desirable that the mold material has toughness and that the processing temperature does not affect the internal hardness.

[0008]

By using the mold of the bending machine of the invention according to claim 1 as described above, the R portion of the mold shoulder formed on the lower mold with which the workpiece slides during bending is more Since it has a large diameter, it will prevent scratches on the work and
Since the relief groove is provided on the V bottom of the mold to drop the waste generated when the work is bent, it is possible to prevent the work from being damaged by the bending waste.

Further, in the die of the bending machine of the present invention according to claim 2, since the surface of the lower die is subjected to a nitriding treatment as a nitriding layer, the surface of the lower die is subjected to a lot of bending work. Even if the above is performed, the mold shoulder of the lower mold is not worn, and the bending accuracy is improved.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. It should be noted that although the press brake will be described as the bending machine, the present invention is not limited to this model, and since the press brake has a known structure, detailed illustration and description thereof will be omitted.

Referring to FIG. 1, the press brake 1 is
Although not shown, a lower table 3 that moves up and down by a hydraulic cylinder or the like is provided in the lower part of the machine body, and a lower die 5 is provided above the lower table 3.

An upper die 9 is provided at the lower end of an upper table 7 hanging from the upper part of the machine body. The upper die 9 and the lower die 5 cooperate to work W.
Is bent.

The lower die 5 is formed with two V dies 11A and 11B extending in the longitudinal direction and having different sizes, and these V dies 11A and 11B are processed according to the processing of the work W. It is selectable. The shoulders 13A and 13B on both sides of the V molds 11A and 11B have large diameter R portions 15A and 15B.
Is formed, and escape grooves 17A and 17B are formed extending in the longitudinal direction at the bottom of the V molds 11A and 11B.

Further, as shown in FIG. 2, a plate 19 is provided on both sides of the lower mold 5 in the longitudinal direction with a fastening member 21.
For example, the lower mold 5 is attached to the lower table 3 by the plate 19 by being locked by a fastening bolt,
Prevents displacement in the longitudinal direction. Reference numeral 23 is a screw for fixing the lower die 5 to the lower table 3.

With the above construction, the work W is placed on the upper surface of the lower die 5, and when the lower table 3 is raised, the lower die 5 rises and cooperates with the upper die 9 to bend the work W into a V-shape. Processing is applied.

As this V-bending process progresses, the work W
The back surface of is processed while sliding the curved surface of the R portion 15A or 15B formed on the lower mold 5. However, since the R portions 15A and 15B have a larger diameter than the R portion formed in the lower die which has been conventionally used, even if the work W slips, no flaw is formed.

Further, since the escape grooves 17A and 17B are formed on the V bottoms of the V molds 11A and 11B, the bending scraps generated during the bending process fall into the escape grooves 17A and 17B, so that the bending scraps are generated. A flaw on the work W can be prevented.

Further, the lower die 5 is subjected to a nitriding treatment. This nitriding process will be described in more detail.
First, regarding the material of the lower die 5, for example, SCM-415 to SCM-445 as chromium molybdenum steel,
Rapid steel is used.

The lower mold 5 made of the above-mentioned mold material is quenched and tempered to have a hardness of HRC 40 or more and then subjected to a nitriding treatment. The nitriding treatment is performed at a temperature slightly lower than the tempering temperature of the material, for example, several hundreds of degrees Celsius. Then, nitrogen is introduced into the mold surface to cure only the surface.

Therefore, unlike plating, there is no risk of peeling, and there is no adverse effect on the pressure resistance of the mold. Also,
It is possible to improve the wear resistance and corrosion resistance of the mold and prevent the generation of rust.

In order to support the above-mentioned features, the experimental results of the inventors are shown in FIG. That is, it is a graph in which the progress of wear of the R portion 15 formed on the shoulder portion (shoulder R: 0.8 mm) of the lower mold 5 is investigated. And R part 1
No wear of 5 was observed.

The present invention is not limited to the above-described embodiments, but can be implemented in other modes by making appropriate changes.

[0023]

As will be understood from the above description of the embodiments, according to the invention of claim 1, a large-diameter R portion is formed on the die shoulder portion on which the lower die is formed. ,
Since the relief groove is provided at the bottom of the die, the radius of the die shoulder portion with which the work slides during bending is large, so that the resistance to the work slipping can be reduced and the wear of the die can be reduced. Further, since the scraps of the work generated during the bending process are dropped into the escape groove provided on the bottom of the mold, the flaws on the work can be reduced.

According to the second aspect of the present invention, the lower mold is subjected to a nitriding treatment to harden the surface thereof, thereby improving wear resistance and corrosion resistance, and improving mold life and bending accuracy. In addition to the improvement, rust was prevented and no preservative was used, so the mold was easy to handle.

[Brief description of drawings]

FIG. 1 is a side view of a lower mold showing a main part of the present invention.

FIG. 2 is a front view of FIG.

FIG. 3 is a graph showing a worn state of a shoulder R portion of a lower mold according to the present invention.

FIG. 4 is a graph showing a worn state of a shoulder R portion of a lower mold in a conventional example.

[Explanation of symbols]

 1 Press brake (bending machine) 5 Lower mold 9 Upper mold 11A, 11B V mold (mold) 13A, 13B Both side shoulders 15A, 15B R part 17A, 17B Escape groove W Work

Claims (2)

[Claims] 1. A bending machine equipped with an upper die for bending a work in cooperation with a lower die, wherein the work has a large diameter on a shoulder portion formed on the lower die with which the work slides. The R part is formed, and an escape groove for dropping the scrap of the work is provided on the bottom of the die formed in the lower die, and the surface of the lower die is nitrided. Bending machine mold. 2. In the nitriding treatment, a lower mold having a quenching and tempering hardness of HRC 40 or more is subjected to nitriding treatment, and the nitriding treatment smoothes a difference in hardness between the nitriding surface hardness and the mold internal hardness. The mold for a bending machine according to claim 1, wherein the mold material has toughness and the internal temperature is not affected by the processing temperature.