JPS6049059B2 - processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a processing device for expanding the end of a pipe or the like.

Conventionally, as a processing method to stretch and mold a part of a pipe or container, there is a hydraulic bulge method in which hydraulic pressure is applied to the inside of the pipe or container, or an elastic material such as rubber is applied inside the pipe or container. The last forming method is known, but
These methods were unable to give very large deformations to the workpiece.

Recently, a opposed hydraulic molding method has been developed that utilizes the hydrostatic pressure effect to obtain a larger deformation rate than the conventional molding method, and molding machines based on this method have already been put into practical use. This forming method is different from the conventional method in that it inserts an elastic body such as a comb inside the workpiece and pressurizes and deforms the elastic body with a punch or the like to stretch the workpiece outward. Although it is similar to the last forming method, since hydrostatic pressure is applied from the outside of the workpiece and the elastic body is pressurized and deformed using a punch, etc., the hydrostatic effect is utilized, and therefore the process is larger than the conventional method. It has the advantage of being able to obtain a deformation rate. Conventionally, when expanding the end of a tube using this method, the mold shown in FIG. 1 was used to carry out the process as shown in FIGS. 2 and 3.

Figure 1 shows an example of a mold when applying the above-mentioned method to pipe expansion processing, where the mold body 1 shows an example of a pipe M to be processed; It has an opening 1a with an inner diameter equal to the outer diameter of the tube M, and a tube expansion cavity lb communicating with the opening 1a in its inner flap. The tube expansion cavity lb is closed by a surface plate 2 fixed to the lower surface of the mold body 1, communicates with a liquid supply passage 3 provided on the surface plate 2, and further communicates with a liquid supply passage 3 provided on the mold body 1. It communicates with the escape passage 4. Pipes equipped with flow rate regulating valves, throttle valves, etc. are connected to these liquid supply passages 3 and liquid relief passages 4, but these are not shown in FIG. Further, the liquid supply passage 3 and the liquid escape passage 4 may serve the same role. (Note that S is a seal or packing.) When expanding the tube M to be processed using a mold having the structure as described above, first, the tube M to be processed is placed in the mold body 1 as shown in FIG. Then, the rubber elastic body 5 is inserted into the tube M to be processed.

At this time, the tip of the tube to be processed M is in contact with the top surface of the surface plate 2, and the tip surface of the elastic body 5 is also in contact with the top surface of the surface plate 2.
On the other hand, since the outer diameter of the elastic body 5 is approximately equal to the inner diameter of the tube M to be processed, the outer peripheral surface of the elastic body 5 is also in contact with the inner surface of the tube M to be processed. Next, the punch 6 is lowered a little to deform the elastic body 5 a little, thereby bringing the outer circumferential surface of the tube to be processed M into close contact with the inner circumferential surface of the opening 1a of the mold. Next, when a valve (not shown) or the like is opened to introduce high-pressure liquid from the liquid supply passage 3 into the tube expansion cavity 1b, hydrostatic pressure is applied to the outside of the pipe M to be processed inside the cavity 1b due to the high-pressure liquid. become. In this state, while keeping the pressure inside the tube expansion cavity 1b constant),
When the punch 6 is pressed down and the elastic body 5 is deformed, the portion of the pipe M to be processed inside the cavity 1b for pipe expansion is expanded as shown in FIG. Continue pressing down with the punch 6 until it comes into close contact with the inner peripheral surface of the cavity 1b. In the above-mentioned known processing method, the pipe is expanded while applying hydrostatic pressure to the outside of the pipe to be processed, so the hydrostatic pressure effect acts on the pipe to be processed and the ductility limit of the pipe to be processed can be expanded. As a result, a larger machining rate can be obtained than with the conventionally known elastoforming method, but according to recent research, products expanded using this method have a shaft on the outer circumferential surface of the expanded portion, as shown in Figure 5. It was found that wavy wrinkles m tend to occur in the direction.
When we investigated the cause of such wrinkles m, we found the following. That is, these defects were due to the following two causes. The first cause occurs at the beginning of machining.4 Simply put, it occurs because the tip of the tube to be processed M is in contact with the surface plate 2 at the beginning of machining.

This will be explained in more detail below. At the beginning of machining, the punch 6 is pressed down as described above, so the outer surface of the elastic body 5 is in close contact with the inner surface of the tube M to be processed.

Next, the liquid is filled into the tube expansion cavity 1b and the punch 6
When the pressure of
The liquid in b is gradually discharged from the liquid escape passage 4,
A portion enters between the wall surface of the opening 1a and lubricates the outer circumferential surface of the tube M to be processed. As a result, the friction between the tube to be processed M and the opening 1a at the opening θ opening portion 1a is reduced, but the outer circumferential surface of the elastic body 5 and the inner circumferential surface of the tube to be processed M are in close contact with each other. Therefore, as the punch 6 presses down, the pipe M to be processed is subjected to a downward axial force. Therefore, the tube to be processed M tries to move downward 5, but since the tip of the tube to be processed M is in contact with the surface plate 2, the tube to be processed M is compressed.
As a result, wrinkles m as described above occur. The second cause occurs during the middle stage of processing, and will be explained with reference to FIG.

In the conventional elastofacing method in which liquid is not filled into the tube expansion cavity 1b, the lower end surface of the elastic body 5 is strongly pressed against the upper surface of the surface plate 2, and the lower end surface of the elastic body 5 is in contact with the upper surface of the surface plate 2. Since a strong frictional force is generated between the upper surface of the surface plate 2 and the lower end of the elastic body 5 is restrained by the surface plate 2, the diameter of the elastic body 5 is expanded and deformed compared to the central position of the elastic body 5. Although it is delayed, in the illustrated processing method in which high-pressure liquid is present in the tube expansion cavity 1b, as the reduction of the punch 6 progresses, the liquid flows between the lower end surface of the elastic body 5 and the upper surface of the surface plate 2. Since it enters and lubricates the lower end surface of the elastic body 5, the restraint of the lower end of the elastic body 5 is weakened, and as a result, the lower end of the elastic body 5 tends to spread outward.

On the other hand, as the processing progresses, the lower end of the tube to be processed M rises, so the lower end of the elastic body 5 is exposed from the tube to be processed M.
Since the restraining force on the lower end is reduced as described above, the end of the elastic body 5 protrudes further outward than the outer circumference of the tube M to be processed, as shown in FIG. The lower end of the tube M is pushed upward more and more, and further axial compressive force is applied to the tube M. As explained above, the conventional opposed hydraulic pressure forming method shown in FIGS. 1 to 4 has the drawback that wrinkles tend to occur at the expanded portion of the pipe to be processed.

Therefore, in order to eliminate these drawbacks, the lower end of the tube to be processed must be held so that it does not touch the surface plate during machining, and the diameter of the tip of the elastic body must be larger than the inner diameter of the tube to be processed. Nuko is necessary. In this invention, the lower end of the pipe to be processed is above the surface plate. In addition, a device is provided to position the lower end of the tube to be processed so that it is held at the same position, and the tip of the elastic body is covered so that the diameter of the tip of the elastic body is not larger than the inner diameter of the tube to be processed during processing. By forming the tube to be thinner than the processing tube, a processing device that does not have the above-mentioned drawbacks is provided.

An embodiment of the present invention will be described below with reference to FIG.

The apparatus shown in FIG. 6 is provided with a device 8 for positioning the lower end of the tube M to be processed above the surface plate 2, and an elastic body 5 whose tip 5a is shaped like a truncated cone. It is characterized by the fact that it is used.

The diameter of the tip 5a of the elastic body 5 is determined so as not to become larger than the inner diameter of the tube M to be processed throughout the entire processing process. The device 8 also includes a pin 8a that protrudes from the inner peripheral surface of the mold body 1 into the tube expansion cavity 1a, and a spring 8b that biases the pin 8a in the axial direction. The spring 8b is accommodated in a horizontal hole 1c provided in the mold body 1, and the pin 8a is retractable into the hole 1c.

A seal 8c is provided at the outlet of the hole 1c to prevent the liquid in the tube expansion cavity 1b from entering the hole 1c. The pipe to be processed M is processed by the processing device as described above.
When performing the tube expansion process, when the tube to be processed M is inserted into the mold, the tip of the tube to be processed M hits the pin 8a protruding into the tube expansion cavity 1b and does not contact the top surface of the surface plate 2. State supported.

Next, when the elastic body 5 is inserted into the tube to be processed M and the punch 6 is pressed down a small amount, the outer peripheral surface of the tube to be processed M is inserted into the opening 1a of the mold.
Closely adheres to the inner circumferential surface of the In the above state, the lower end of the tube N to be processed is not in contact with the surface plate 2, so even if an axial force is applied from the elastic body 5, no axial reddening force is applied to the tube M to be processed. next,
When the tube expansion cavity 1b is filled with liquid and the punch is lowered while applying hydrostatic pressure from the outside of the tube to be processed M, a large axial force is applied to the tube to be processed M and the elastic body 5 is compressed. The tube M is deformed and expanded, and the lower end of the tube M to be processed is pulled upward. Further, as a result, the spring 8b is compressed via the pin 8a, and since the pin 8a and the lower end of the tube to be processed M do not collide with the surface plate 2, no axial compressive force is applied to the tube to be processed. On the other hand, the diameter of the tip 5a of the elastic body 5 does not become larger than the inner diameter of the tube M to be processed even when the elastic body 5 is greatly compressed. is not pushed up. As described above, according to the apparatus of the present invention, the drawbacks of the conventional opposed hydraulic forming method can be eliminated, and workpieces such as pipes can be processed at a high processing rate and defects such as wrinkles can be avoided. It can be processed into pieces.

Incidentally, FIG. 7 shows a modified embodiment of the device 8 for positioning the lower end of the pipe to be processed.

In the embodiment shown in FIG. 7, the hole 1c accommodating the spring 8b and the tube expansion cavity 1b are connected as a passage 1d, and the hole 11
The high-pressure liquid in the tube expansion cavity 1b is introduced into the tube C. Therefore, the force that causes the pin 8a to protrude into the tube expansion cavity 1b is strengthened. As the device 8 for positioning the lower end of the tube M to be processed, it goes without saying that not only the device shown in the illustrated embodiment but also a device using a shilling can be used.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing an example of a θ-shaped mold used in a conventionally known opposed hydraulic molding method, FIG. 2 is a diagram showing the state before the start of processing in the conventional method, and FIG. 3 is a conventional FIG. 4 is a diagram illustrating the situation when the method is ideally carried out, and FIG. 4 is a diagram illustrating the drawbacks that occur in the conventional method.

Claims (1)

[Claims] 1. A mold body having a small-diameter opening that is approximately equal to the outside diameter of a workpiece such as a pipe, and a large-diameter tube expansion cavity that communicates with the opening, and a mold body that is fixed to the lower end of the mold body and has a Deforming the elastic body in the workpiece with a punch while applying hydrostatic pressure from the outside of the workpiece inside the pipe expansion cavity using a mold consisting of a surface plate that closes the pipe expansion cavity. In a processing device for stretch-forming the workpiece, the tip of the elastic body is formed so as not to be larger than the inner diameter of the lower end of the workpiece, and the lower end of the workpiece is 1. A processing device for expanding a pipe, etc., characterized in that a device for positioning the surface plate is positioned above the surface plate.