JPS625693B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is capable of forging a nut material or hollow product having a through hole in the center by hitting a piercing pin against a blank, or forming a cup-shaped product by recessing the end face of the blank. A method for detecting the diameter of a piercing hole in a homer used for heading forming, in which the degree of wear of the piercing pin exceeds an allowable limit by using the pressurizing force generated when the blank bites into the piercing pin, and the method thereof. and an apparatus for directly carrying out the method.

Homer's piercing device presses a piercing pin against the blank in the final stage of the forging process to punch out a hole, but as shown in Figure 6, the conventional piercing pin has a head 1 attached to the tip of a shaft 2. The blank 4 is supported by the head 1 of a fixed piercing pin when punching a hole, and a hollow cylindrical shape is attached to the head 1 of a fixed piercing pin. Since the punch is punched out at once by pressing the core punch 5 for making the hole, the degree of wear and damage on the head is much greater than that of punches and dies used in other heading processes. Moreover, even slight wear on the piercing pin affects the diameter of the piercing hole, so when precision machining is required, it is necessary to constantly monitor the finished dimensions even while the machine is running.
In reality, there was no other way than to examine each punched product one by one and make a decision.

Therefore, in this invention, when the piercing pin wears below the minimum tolerance limit dimension, the blank with the hole punched bites into the piercing to apply pressure, thereby reducing the pressure that has dropped once the hole is completed. When the machine goes up again at a point, it is detected by a sensor to detect the degree of wear on the piercing pin during continuous operation of the machine, and when the limit is reached, it can be stopped immediately, completely eliminating the above-mentioned drawbacks of the conventional method. It is.

The drawings will be explained below.

1 and 2 are cross-sectional views of a piercing device that implements the method of the present invention, in which a piercing pin 10 has a piercing head 11 with a piercing hole diameter A as the maximum allowable dimension, and an outer diameter B as the minimum tolerance dimension with respect to the piercing hole diameter A. When the piercing head 11 plunges into the blank 13, the shoulder 14 at the tip of the circumferential body also plunges into the piercing hole 13a, following the head 11. The length C of the constricted portion 14a is made shorter than the conventional length C' and is integrally formed.

A piercing pin 10 like this is placed in a die case 1.
5 so that the rear end 10a is supported in contact with the support stand 16, and a hollow cylindrical core punch 18 for punching holes is provided protruding from the punch case 17 on the corresponding punch side, and a movable ram (not shown) During each reciprocating operation (omitted), the core punch 18 repeatedly moves forward and backward, and when moving forward, the tip of the core punch 18 fits externally into the piercing pin 10 in the die 19, and the blank 13 supplied therebetween is punched. It is something to do. A strain gauge 20 for detecting pressure such as a load cell is provided on the support base 16, and by bringing the rear end 10a of the piercing 10 into direct contact with the gauge surface, when pressure is applied to the piercing pin 10, the strain gauge 20 is This can be reflected directly on the strain gauge 20.

A stripper 21 is a hollow cylindrical body that is slidably fitted onto the piercing pin 10, and is used to extrude the punched blank 13 from the die 19. 22 is the knockout pin, and the machine frame 23
The stripper 21 is pushed forward through the push rod 25 and the intermediate pin 26 with each movement of the knockout lever 24 provided at the rear of the stripper. Reference numeral 27 denotes a knockout strain gauge provided on the knockout lever 24, and this strain gauge 27 detects changes in the pressure applied to the piercing pin 10 at the time of knockout. The strain gauge 27 may be provided on the arm portion 24a of the lever 24 that receives resistance during pushing, or may be provided on a part of the pushing mechanism such as a connecting portion with the push rod 25 or the intermediate pin 26.

When the blank, which has been forged in the forging section and has not yet been punched, is press-fitted into the die 19 by the core punch 18 just before the piercing pin 10, the piercing head 1 with the center of the blank 13 fixed.
1, the piercing force of the core punch 18 causes the piercing to be performed at once, and at the forward upper limit position of the punch 18, the punched blank 13 touches the head 11 of the piercing pin 10, as shown in FIGS. 1 and 2. It pierces through and is fitted into the circumferential trunk portion 12. At this time, if the wear of the piercing head 11 is small, the outer diameter A is at least larger than the minimum tolerance dimension B, so a gap is created between the hole diameter and the circumferential body 12, so that no pressing force is applied. As the wear of the head 11 progresses and its outer diameter A approaches B, the hole diameter gradually becomes smaller.
Blank 13 was finally punched when it became AB.
At the same time as the hole punching is completed, the tip shoulder portion 14 of the circumferential body portion 12 is
It bites into the shoulder part 14 in a strong manner, and pressurizing force is applied to the shoulder part 14 from the entire circumference. Therefore, at the forward upper limit position (bottom dead center) of the punch 18, the pressing force that has once decreased increases again. This increase in pressure is directly reflected on the strain gauge 20 that supports the piercing pin 10, so if it is detected and wear has reached its limit, the machine can be stopped immediately and a new piercing pin replaced. exchange with. After the hole is removed, the knockout lever 24 is operated to release the knockout pin 2.
2 is pushed, and as a result, the blank 13 that was previously pushed into the back is pushed out from inside the die 19 by the stripper 21, but even during this extrusion, until now, the knockout pin has been pressed with a pushing force below a certain value. The blank that was being pushed is bitten by the piercing pin and the pressing force increases, causing a sudden increase in extrusion resistance, which is reflected on the knockout strain gauge 27, so the degree of wear on the piercing pin head increases. can be read moment by moment.

FIG. 5 shows a method of pressing a solid punch 18' against the piercing pin 10 to form a recessed hole 13b in the end face of the blank 13'. At the same time, when the shoulder portion 14 fits into the recessed hole 13b and the head wears beyond the limit, it strongly bites into the shoulder portion and applies pressure, and the change is reflected on the strain gauge. be. Further, there are cases where the piercing pin is attached to the punch side and acts in a movable manner, but in this case as well, changes in the pressing force can be reflected on the strain gauge in the same manner as described above. However, in this case, it is necessary to provide a strain gauge on the punch support, or on the punch support and the punch-side knockout mechanism.

As explained above, in this invention, depending on the degree of wear on the piercing pin that performs hole punching, the punched blank bites in a pressurized manner at the same time as the hole punching is completed, and pressurizing force is applied to the piercing pin. When the downward pressure increases again, the strain gauge detects that the piercing head is worn beyond the limit.The degree of wear is measured by the pressure of the blank itself immediately after drilling, so the strain gauge detects the wear. Detection is accurate and it is possible to immediately send a signal to the stop mechanism to stop the machine. Furthermore, the degree of wear on the piercing pin can be accurately recognized at any time even during operation, which prevents the occurrence of many defective products and ensures accuracy. The overall configuration of the device is almost the same as the conventional device, with only a slight change in the shape of the piercing pin. Since there is no need to specially install equipment, it is easy to implement and can be implemented at low cost.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a longitudinal side view of the piercing device, Fig. 2 is an enlarged side view of the head of the piercing pin, and Fig. 3 is a partially longitudinal side view of the knockout mechanism. 4 is an enlarged sectional view of the piercing device immediately after the hole has been punched, FIG. It is a partial side view of a piercing pin. 10... Piercing pin, 11... Head, 12
... Circumference of the trunk, 13 ... Blank, 14 ... Shoulder part,
16... Support stand, 20, 27... Strain gauge, 24
...Knock out lever.

Claims (1)

[Claims] 1. In a piercing method in which a piercing pin is relatively inserted into a blank supported in a fixed position to form a hole through or in a concave manner, the head of the piercing pin penetrates into the blank. At this time, the shoulder at the tip of the circumferential body following the head was also placed so that it would fit into the hole immediately after the piercing, and the shoulder would fit into the inner surface of the hole under pressure depending on the degree of abrasion and diameter reduction of the head. A method for detecting the diameter of a piercing hole in a homer, which is characterized in that the change in pressure is sometimes detected with a strain gauge provided on a piercing pin support. 2. In a piercing device configured to relatively plunge a piercing pin into a blank supported in a fixed position to perform piercing or recessed hole drilling, the piercing pin is set so that the diameter of the piercing hole is the maximum allowable dimension. It consists of a piercing head with a diameter of 100 mm, and a circumferential body whose outer periphery has the minimum tolerance dimension for the piercing hole diameter. Piercing hole diameter detection in a homer, characterized in that the shaft is integrally formed with a narrow constricted part in the middle so as to penetrate, and a strain gauge is provided so that the rear end of the pin directly contacts the support of the piercing pin. Device. 3. Changes in the pressing force applied to the piercing pin are detected by a strain gauge provided in the pushing mechanism when the stripper for extruding the product fitted to the piercing pin is pushed by the knockout lever. A method for detecting the diameter of a piercing hole in a homer according to claim 1.