JP2806087B2 - Mold crack prevention device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for preventing cracks in a mold for forming a cold forging die or the like.

[0002]

2. Description of the Related Art A cold forging press is used to efficiently produce mass-produced mechanical parts with high braking. This press includes a lower die and an upper die each having a concave portion having a shape corresponding to the final shape of the product.The upper die is moved downward while the product material is installed in the lower die, and the both die are moved. By plastically deforming the product material by cooperation, a product having a predetermined shape is plastically processed.

In such a cold forging press, since both upper and lower dies are subjected to a large load during forging, a high-hardness abnormal material other than a product material having a predetermined shape and a predetermined material is used. When forging is performed, there is a possibility that the forging die itself may cause a mold crack. Conventionally, in order to prevent such a situation from occurring, a load detector having a strain gauge is provided on one of the upper and lower dies to detect internal strain of the die generated during forging. Then, the data from the load detector is constantly monitored, and when the maximum load applied to the forging die exceeds a predetermined value, the operation of the forging press is stopped to prevent the occurrence of die cracking of the forging press. I have to.

[0004]

However, in a system using such a strain gauge, if the mold itself does not have a predetermined internal strain, the situation cannot be detected.
It was only detected that a high hardness abnormal material that could induce a mold crack when a high load was applied to the forging die was machined. Therefore, even if an appropriate load is applied to the product material, if a material that causes cracking of the product product due to the load, for example, a product material of a different material is processed, the Could not be detected. The present invention has been made in view of the above prior art, and detects when a different material such as a product crack occurs is processed, and detects a defective product in a processing line. The purpose is to do.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a forging die in which a product material is installed.
Mounted so as to be opposed across the part of the forging die, the product material to be processed from this the forging die is generated on the forging machine to strain energy and the time of processing at the time of plastic deformation
A for detecting elastic waves generated due to strain energy
And E sensor, the whether or the forged products materials is occurring or product cracking has become a proper machining conditions
A determination unit that determines whether or not there is a risk of mold breakage based on a signal from the AE sensor; and an output unit that issues an output signal to an external device based on a determination result of the determination unit. It is a mold crack prevention device.

[0006]

In the present invention having the above structure, the number of elastic wave events detected by the AE sensor and the number of product cracks and
And the relationship with die cracks generated in the forging die is measured in advance and converted into data. Based on this data, this in the course of forging the material using a forging mold, when the number of events is a predetermined number or more is that the product cracks are generated in the product
Judging that there is a possibility that the forging die may cause mold cracking ,
Remove the product from the production line or
Stop the operation and display the status on the display, etc.
Or

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. FIG. 1 is a view showing a mold crack preventing device according to the present invention. FIG. 1 shows a lower mold 11 among forging dies attached to a bolster 10. An upper die (not shown) is provided above the lower die 11 so as to be vertically movable.
In a state where the product material W is installed in the concave portion 12 having the shape corresponding to the shape of the product in FIG. 1, the upper material is moved down, whereby the product material W is plastically worked by the cooperation of the two dies. In the case illustrated, a pinion shaft is manufactured by forging.

An AE (acoustic emission) sensor 13 is attached to the lower mold 11. This AE
The sensor 13 is a sensor for detecting an elastic wave caused by the strain energy generated inside the material W at the time of plastic deformation of the material W and the strain energy generated at the time of working the lower mold 11, actually, an ultrasonic wave. The larger the load applied to the forging die 11 and the material W, the larger the number of generated, that is, the number of events, and the amplitude of the elastic wave detected by the sensor 13 increases. The signal from the AE sensor 13 is sent to a parameter processing unit 17 via a preamplifier 14, a multi-stage filter 15, and a main amplifier 16, where the signal processing is performed. The signal processed here is subjected to signal analysis in the AE signal analyzer 18.

The signal A analyzed by the AE signal analyzer 18
FIG. 2 shows an experimental result of measuring the relationship between the number of E events and the situation of the forged product and the forging die. In this experiment, the number of events was counted by extracting an elastic wave in a specific frequency band (200 KHz band) using the multi-stage filter 15.

According to this experiment, when the number of events exceeds 200, it is detected that a product crack has occurred inside the forged product, and when the number of events exceeds 240, the inside of the forging die has been detected. It was detected that a mold crack had occurred. It was found that the optimal product was obtained when the number of events was in the range of about 120 to 140. Therefore, for example, if the threshold of the number of events is set to 200 in accordance with the size and type of the product to be processed, if the number of events obtained by the AE sensor 13 exceeds this threshold, the product is defective. And remove it from the production line. The number of events is 24
If it exceeds 0, the forging die may crack.For example, to prevent the occurrence of cracking when the number of events exceeds 220, stop the forging line and display the situation. It is displayed on a unit or the like, and an alarm buzzer or an alarm lamp is activated.

Next, a forging operation by a forging press having the mold crack preventing device of the present invention will be described with reference to a flowchart shown in FIG. First, the product material W preformed into a predetermined shape is installed on the lower mold 11 by a transfer device (not shown), and in this state, the forging press is activated to move the upper mold downward toward the lower mold 11. Let it. At the same time, the detection of the elastic wave by the AE sensor 13 is started in step S1 in FIG. 3, and the AE signal analyzer 18 counts the number of events of the elastic wave. For example, when the number of events reaches a product crack threshold of 200 in the process of forging, it is determined in step S2 that the product material is a different material, that is, a defective product. In step S3, the process proceeds to step S4.
In addition to displaying on the display unit that the product processed in step 2 is defective, the defective product is excluded from the processing line in step S5. As a case where it is determined to be defective, when the hardness of the material is defective, or when the hardness is appropriate, a dissimilar material or the like whose size etc. is not the predetermined size is used. Is the case.

On the other hand, in step S3, it is determined whether or not the number of events is equal to or greater than a threshold value for preventing a mold crack. This threshold is set to, for example, 220, and when it reaches this value, step S6 is performed to prevent mold cracking.
And the status is displayed on the display unit in step S7, and an output signal is supplied to an alarm buzzer or an alarm lamp. Since the product crack threshold and the mold crack prevention threshold differ depending on the size and material of the product material to be processed, the data is collected in advance by experiments, and the respective thresholds are set according to the product. As described above, according to the present invention, the operation of the forging press can be stopped in order to prevent the mold crack by predicting the danger in advance before the mold crack occurs. As compared with the case where the processing line is stopped, the operation rate of the manufacturing equipment is greatly improved, and the production efficiency is improved. In addition, the present invention not only can prevent the occurrence of mold cracking in advance,
When a material of a different material that does not have a predetermined size or a material of poor hardness that does not have a predetermined hardness is processed, it can be detected while processing the material. At the stage, the defective products can be eliminated from the line, and unnecessary processing of transferring unnecessary materials to the subsequent processing device and processing there is prevented,
The product quality assurance ability has been greatly improved. Further, in the illustrated embodiment, the present invention is applied to forging of a pinion shaft as an automobile part. However, the present invention is applicable to any product as long as it is a forging using a die. can do.

[0013]

As evident from the foregoing description, according to the present invention, if the proper material is not used for forging, advance Runode, the mold cracking can detect it automatically
To greatly improve production efficiency and forging
Defective products can be removed from the production line
As a result, the quality assurance ability of the product improved.

[Brief description of the drawings]

FIG. 1 is a schematic view showing the entire structure of a mold breaking prevention device of the present invention;

FIG. 2 is a graph showing the relationship between the number of AE events and product cracks and mold cracks;

FIG. 3 is a flowchart showing an operation state of the mold breaking prevention device.

[Explanation of symbols]

11 ... forging die, 13 ... AE ... sensor, 18 ... AE signal analysis unit (determination means, output means), W ... material.

Claims (1)

(57) [Claims] 1. A recess of a forging die in which a product material is installed.
And across the portion of the forging die is mounted so as to be opposed, the product material to be processed from this the forging die is generated on the forging machine to strain energy and the time of processing at the time of plastic deformation
A for detecting elastic waves generated due to strain energy
E sensor and whether or not the product material is in an appropriate processing state or whether a product crack has occurred and the forging die has a mold crack
A mold breaking preventing device comprising: a discriminating means for discriminating whether or not there is a fear of being based on a signal from the AE sensor; and an output means for outputting an output signal to an external device based on a discrimination result of the discriminating means. .