JPH0154128B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention reduces the diameter of the end of a circular tube by pressing a drawing tool against a rotating circular tube and moving it back and forth in the axial direction of the circular tube. This invention relates to a method of narrowing the opening of a circular tube to make it smaller.

In addition, in this specification, "method for narrowing the opening of a circular pipe"
This includes not only the method of squeezing a circular tube so that the diameter of the tube end becomes smaller, but also the method of squeezing a circular tube so that the diameter of the slightly inner part of the tube end becomes smaller without squeezing the tube end at all. Interpret it in a broad sense.

[Conventional technology]

Conventional methods for drawing the mouth of circular tubes can be roughly divided into methods that use a mold and methods that do not use a mold.

One of the former methods is shown in FIG. 5, which uses a mold 11 whose tip 11a corresponds to the drawing shape of the end of the target circular tube, and Insert the mold 11 into the pipe end of the circular pipe P,
In this method, the roller 12 is pressed against the end of the circular tube P while rotating the circular tube P in this state to squeeze the opening.

This neck drawing method has the advantage that the shape of the end of the circular tube follows the shape of the tip of the mold, so the overall shape of the drawn part can be easily made into the desired shape. On the other hand, since the pipe is drawn to follow the mold inserted into the circular pipe, there is a problem that the drawing shape is limited to the outer shape of the mold, and it is not possible to draw both ends of the pipe.

In addition, as another method of the former method,
Some of these are described in Publication No. 106664, and are summarized as follows. Note that the drawings and part numbers are those listed in the official gazette.

An annular outer molding member 92 for molding the outside of the can body member 30 and a cylindrical first molding member 1 for molding the inside of the can body member 30
60 and a second molded member 184.

The outer diameter of the first molded member 160 is smaller than the outer diameter of the second molded member 184, and when viewed from the axial direction, the first molded member 160 is smaller than the outer diameter of the second molded member 184.
4, the first molded member 160 and the second molded member 184 are rotatably supported by mutually eccentric shafts, and the first molded member 160 and the second molded member 184
can be separated from each other from the close contact state against the elastic force of the spring.

The reason why the outer diameter of the first molded member 160 is smaller than the outer diameter of the second molded member 184 is that the first molded member 160 is
This is so that it can be relatively removed.

The eccentric mechanism allows the first molding member 160 and the second molding member 184 to integrally move eccentrically in the radial direction of the outer molding member 92.

The outside of the can body member 30 is supported by the cylindrical sleeve member 114 so that the first molded member 160 is completely inserted into the can body member 30, and the end of the second molded member 184 is inserted into the can body member 30. Insert into the end of the tube. In this state, the first molded member 160 and the second molded member are
When the molding member 184 is moved eccentrically, each member 1
60, 184 is the rotating outer molding member 9
2, the first molded member 16
The outer molded member 92 enters between the close contact portions of the portions of the outer peripheries of the 0 and second molded members 184 that have a common generatrix, and the outer molded member 92 enters the first molded member 160.
and the second molded member 184 gradually separate from each other, so that the tube end of the can body member 30 is squeezed and at the same time can be flanged.

The first molding member 160 and the second molding member 184 are supported by eccentric shafts, and the outer diameter of the first molding member 160 is much smaller than the inner diameter of the can body member 30. After molding, the first molded member 160 can be removed from the inside of the can body member 30 by passing through the constricted portion of the can body member 30.

The method for closing the opening of a circular tube described in Japanese Patent Application Laid-Open No. 106664/1983 has the following problems because it has the above-described structure and operation.

Two different molds (a first molding member 160 and a second molding member 184) are inserted into the portions on both sides of the drawing area of the can body member 30, and the molds (outer molding) are inserted from the outside of the can body member 30. Since the opening is drawn by pressing the member 92) between the close contact parts of the two molds inserted into the can body member 30, the drawn shape is similar to that of the can body member 3.
It is determined by the outer peripheral surface shapes of the two molds inserted into the mold. Therefore, this mouth squeezing method is
This is a type of spatula drawing in which the drawing process follows the shape of the mold, and there is no degree of freedom in forming.

The annular mold (outer molding member 92) for molding the outside of the can body member 30 can only move relative to the can body member 30 in its radial direction, and cannot move in its axial direction. Since there is no pressure, the constricted portion is constricted by tensile deformation while being squeezed. For this reason, the narrower the narrower the narrower the narrower the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner as the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the narrowing becomes, the the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner the thinner as the thinner the thinner the thinner the thinner the thinner the thinner the thinner the constricted part becomes, the thinner the constricted part ends up being broken.

In addition, another reason why it is not possible to reduce the size to a large extent is that the two molds inserted into the can body member 30 are integrated via an eccentric shaft.
One of the molds may not be able to be relatively removed from the can body member 30 unless it passes through the constricted portion of the can body member 30.

An eccentric mechanism for eccentrically moving the mold to be inserted into the can body member 30 is required, and the structure of the apparatus for carrying out the process becomes complicated.

Furthermore, as another method of drawing the mouth of a circular pipe using a mold, there is a reference to "Rotational Plastic Processing", a work by Masujiro Hayama, published by Kindai Editorial Co., Ltd. on April 1, 1981. There is something described in Figure 12.35 on page 479, and Figure 6 shows this in an easy-to-understand manner.

This is the chuck 2 of the tube body 21 which is the workpiece.
2, insert the support mold 23 from the open end of the tube 21, press the roller 24 against the tube 21 while rotating the tube 21 in this state,
This is a processing method in which the tube body 21 is moved in both the axial direction and the radial direction to draw the opening.

However, as is clear from the figure, the end surface of the open end of the tube 21 is not regulated at all along the axial direction of the tube 21, so as the molding progresses, the end surface of the tube 21 changes. It moves in the axial direction.

Therefore, the deformations that occur at the end of the tube body 21 include deformations that contribute to the narrowing of the tube, such as reducing the radius of this portion, and deformations that do not contribute to narrowing, such as increasing the length of this portion. These two factors are included, and therefore the molding efficiency is poor. Furthermore, the tube body 21
Since the end face is not regulated at all along the axial direction, it is not possible to perform molding by rotating the tube body 21 at high speed or by increasing the pressing force applied to the tube body 21 by the rolls 24. , molding takes time, and molding efficiency is also poor in this respect.

On the other hand, in the method of drawing a circular pipe without using a mold, the pipe end is drawn into a so-called cantilever shape, so when pressing rollers to deform the pipe end, it is necessary to reduce the diameter of the pipe. The bending deformation becomes larger than the shear deformation that contributes to the deformation, reducing processing efficiency and causing buckling, or tensile stress caused by the bending deformation occurs at the edge of the circular tube, causing cracks in that part. This may occur, and there is a problem that the material cannot be narrowed to a large extent unless it is made of a highly ductile material such as copper or aluminum.

[Problem to be solved by the invention]

In view of the problems of the conventional circular tube opening method as described above, the present invention has been developed by inserting a deformation prevention mold into the end of the circular tube and at the same time By bringing the end surface into contact with the movement-preventing mold, the end of the circular tube is not deformed at all during forming, and furthermore, the end surface of the circular tube is prevented from moving in the axial direction. , the deformation that occurs at the end of the circular tube is limited to the deformation that contributes to the opening, and
The objective was to improve the efficiency of drawing by making it possible to draw a circular tube in a short time with a large drawing force.

[Means to solve the problem]

A first invention relates to a method for drawing a circular pipe in which a drawing tool is pressed against a rotating circular pipe to reduce the diameter of the end of the circular pipe, and a drawing part of the circular pipe and a product inside the pipe are provided. A deformation prevention mold for preventing drawing deformation is inserted only into the non-product part provided at the end of the circular tube, without inserting a mold into the section, and at the same time, the end of the circular tube is The end surface of the circular tube is brought into contact with the movement prevention mold to prevent it from moving along the pipe, and in this state, the circular tube is rotated and the drawing tool is pressed against the boundary between the product part and the non-product part of the circular pipe. The opening of the circular tube is characterized in that the boundary portion is squeezed by reciprocating in the axial direction of the circular tube, and then the minimum diameter portion of the squeezed portion of the circular tube is cut to remove the non-product portion. This is a narrowing method.

The second invention is a method for drawing a circular pipe in which the diameter of the end of the circular pipe is reduced by pressing a drawing tool against the rotating circular pipe. Instead of inserting a mold, a deformation prevention mold is inserted only into the end of the circular tube to prevent drawing deformation, and the end of the circular tube is inserted so that the end of the circular tube does not move along the axial direction. The tube end surface of the tube is brought into contact with the movement prevention mold, and in this state, the circular tube is rotated, and the drawing tool is pressed against the tube end of the circular tube while reciprocating in the axial direction of the circular tube, thereby reciprocating the tube end. This is a method of squeezing the mouth of a circular tube.

[Action of the invention]

A deformation prevention mold is inserted into the end of the circular tube to prevent deformation of this part, and the pipe end surface of the narrowed part of the circular tube is in contact with the movement prevention mold, so that forming is not possible. Even as the tube advances, the end of the circular tube does not deform at all, and the tube end surface cannot move in the axial direction of the circular tube.While this movement-preventing mold receives a large force from the end surface of the circular tube, Mouth tightening work is performed.

In this way, the movement-preventing mold receives a large force from the end face of the circular tube, and the movement-preventing mold prevents the end of the circular tube from deforming. Since the tube end of the circular tube is not deformed at all and the end surface thereof does not escape in the axial direction, the deformation that occurs at the tube end of the circular tube is a deformation that contributes only to the opening.

Moreover, the structure is such that the end face of the circular tube does not escape in the axial direction as the drawing progresses, so there is no problem even if the rotating speed of the circular tube is increased and the pressing force of the drawing tool against the circular tube is increased. The opening of the circular tube can be narrowed to a large extent and in a short time.

〔Example〕

First, the first invention will be explained. In Figs. 1 and 2, no mold is inserted into the product part _P2 , which is inside the non-product part _P1 provided at the end of the circular pipe P, and only into the non-product part _P1 . A cylindrical deformation prevention mold 1 for preventing drawing deformation is inserted, and in this state, the product part P ₂ of the circular tube P is gripped by the chuck 2 and the circular tube P is driven to rotate. The deformation prevention mold 1 is held by another chuck 3, and the end surface of the end of the circular tube P is in contact with the tip surface of this chuck 3. Therefore, in this embodiment, the chuck 3 holding the deformation prevention mold 1 functions as a movement prevention mold to prevent the end face of the circular tube P from moving in the axial direction during molding. Also plays a role.

When the circular tube P is driven to rotate, the deformation prevention mold 1 inserted into the end of the circular tube P rotates as a unit.

In this state, the roller 4, which freely rotates around the rotation axis C, is pressed against the boundary part B between the product part _P2 and the non-product part _P1 of the circular pipe P, and is reciprocated in the axial direction of the circular pipe P. Move forward gradually.

That is, the rollers 4 are moved forward by a predetermined amount in the radial direction of the circular tube P, then moved in the axial direction of the circular tube P, and when the moving end is reached, the rollers 4 are moved further in the radial direction of the circular tube P by a predetermined amount. Move the roller 4 forward, then move the roller 4 in the opposite direction to the above, and repeat this operation to remove the circular tube P.
The boundary part B between the product part _P2 and the non-product part _P1 is narrowed down.

In this way, when the roller 4 is moved back and forth in the axial direction while pressing against the circular pipe P, the boundary portion B of the circular pipe P is deformed by both the compressive force and the shear force, and as shown in FIG. The results are narrowed down sequentially as shown in C to C. After the drawing process is completed, the deformation prevention die 1 inserted into the end of the circular tube P is removed. Note that the amount of movement of the roller 4 in the axial direction of the circular tube P needs to be gradually reduced as the aperture progresses.

The deformation prevention die 1 is inserted into the end of the circular tube P, and the end surface of the circular tube P is in contact with the chuck 3, so that the end cannot be moved in the axial direction. Since the opening is drawn, the end of the circular tube P is not deformed at all before and after forming, and at the same time, the end surface of the circular tube P is not moved at all along its axial direction.

Here, since the end surface of the circular tube P is in contact with the chuck 3, the structure is such that the end of the circular tube P does not escape in the axial direction even if the forming progresses.
The only deformation that occurs at the end of the circular pipe P is the deformation that reduces the radius of this part and contributes to the opening.
Therefore, the aperture efficiency becomes high.

Moreover, since the chuck 3 prevents the pipe end of the circular pipe P from escaping in the axial direction, even if both the rotational speed of the circular pipe P and the pressing force by the rollers 4 are increased, there is no problem. Since the end of the circular tube P can be squeezed without any effort, the end of the circular tube P can be held with great force and the mouth can be squeezed in a short time, and the squeezing efficiency is high in this respect as well.

In addition, a deformation prevention mold 1 is inserted into the end of the circular tube P to prevent the deformation due to the restriction, and the roller 4 is pressed against the circular tube P while reciprocating in its axial direction. There is no or almost no bending deformation in the part, and the tube is narrowed by only two types of deformation: compressive deformation, which contributes to reducing the diameter of the circular pipe P, and shear deformation. Therefore, cracks and buckling do not occur in the minimum diameter portion A of the squeezed portion, and even if the pressing force of the roller 4 is reduced, the squeezed portion can be squeezed large and in a short time.

In addition, the deformation prevention mold 1 inserted into the pipe end of the circular pipe P has a function only to prevent drawing deformation when drawing the inside of the pipe end, and the deformation prevention mold 1 is inserted into the pipe end of the pipe P. Since no mold (forming die) is inserted, the drawing shape can be freely selected, and the degree of freedom in drawing forming is extremely high.

Furthermore, while pressing the roller 4 against the circular tube P,
Since drawing is performed by reciprocating the axial direction of the
The material of the drawn part is deformed by both compressive force and shear force, and as in the case where drawing is performed by moving the roller 4 only in the radial direction of the circular pipe P, the material of the drawn part deforms. Although it is slightly distorted by tensile force, it will not become extremely thin. On the other hand, due to the compressive deformation caused by reciprocating the roller 4 in the axial direction of the circular tube P, the material in the constricted part becomes thicker than in other parts, as shown in FIGS. 2A to 2C. The larger the stroke of the reciprocating movement of the roller 4, the thicker the material in the squeezed part).
For this reason, it is possible to narrow down the field to a large extent.

When the circular tube P is drawn by the method described above, the end of the circular tube P is squeezed as shown in Figure 3A, and the circular tube P is cut at the minimum diameter portion A of the drawn portion. When the non-product portion P ₁ is removed, the end of the product portion P ₂ of the circular tube P is squeezed into the desired shape, as shown in the same figure.

Furthermore, in the method of drawing the mouth of a circular pipe according to the first invention, no mold is inserted into the product part _P2 inside the non-product part _P1 provided at the end of the circular pipe P, and the non-product part is _P1
Since the drawing process is performed by inserting the deformation prevention die 1 into the pipe, a non-product part P ₁ is provided at both ends of the circular tube P as shown in FIG. 4, and the non-product part P ₁ and the product part P ₂
Both ends of the circular pipe P can be squeezed by squeezing each boundary portion B with the above-described method, and then cutting at each boundary portion B to remove the non-product portion _P1 .

Further, the second invention is a method for drawing the end of a circular pipe in the case of a completed product or part in the state shown in FIG. 3A or FIG. This is for cases where small diameter portions are not cut. The second aspect of the invention is also a method of squeezing the slightly inner part of the mold inserted into the end of the tube, so both ends of the circular tube can be squeezed.

In the above embodiment, a driven rotating roller was used as the drawing tool, but the drawing tool may be a driven rotating roller or a non-rotating tool having a curved tip.

〔Effect of the invention〕

The present invention provides a deformation prevention mold for preventing drawing deformation only in a non-product part provided at the end of a circular pipe, without inserting a mold into the part to be drawn and the product part inside the pipe. is inserted, and the end of the circular tube is brought into contact with a movement prevention mold to prevent the end of the circular tube from moving along the axial direction, and the mouth of the circular tube is squeezed. Even when forming progresses, the end of the circular tube does not deform at all, and at the same time, the end surface of the tube does not move in the axial direction of the circular tube, and this movement-preventing mold prevents the end surface of the circular tube from moving in the axial direction. Mouth drawing and forming is performed while receiving a large force from.

In this way, the movement-preventing mold receives a large force from the end surface of the circular tube, and this movement-preventing mold prevents the end of the circular tube from deforming along its axial direction. Since the structure is such that the end surface of the circular tube does not escape in the axial direction as the narrowing progresses, the deformation that occurs at the end of the circular tube only contributes to the narrowing that reduces the radius of this part. It is a deformation.

Moreover, the structure is such that the end face of the circular tube does not escape in the axial direction as the drawing progresses, so there is no problem even if the rotating speed of the circular tube is increased and the pressing force of the drawing tool against the circular tube is increased. This point, combined with the fact that the deformation that occurs at the end of the circular tube described above is a deformation that contributes only to the opening, makes it possible to increase the opening of the circular tube and to make it possible to This can be done in a short time.

[Brief explanation of drawings]

1 to 4 are diagrams for explaining the present invention, and FIG. 1 is a cross-sectional view of a state in which a deformation prevention mold 1 is inserted into the end of a circular pipe P held by a chuck 2. Figures 2A to 2C are cross-sectional views showing the process in which the boundary part B between the non-product part _P1 and the product part _P2 of the circular tube P is squeezed by the rollers 4, and Figure 3A shows the process in which the boundary part B is squeezed by the roller 4. A cross-sectional view of a circular pipe P that has been squeezed;
Figure 4 A shows a circular pipe P whose boundary parts B at both ends are constricted.
This is a cross-sectional view of a circular pipe P which is cut at each boundary portion B and both pipe ends are narrowed. Figure 5 shows
FIG. 6 is a cross-sectional view for explaining a conventional mouth drawing method using a mold, and FIG. 6 shows a support mold (forming mold).
FIG. 3 is a cross-sectional view for explaining yet another conventional mouth tightening method using the method. [Explanation of symbols of main parts], A: Minimum diameter part of the squeezed part, B: Boundary part between product part and non-product part of circular pipe, C: Rotation axis of roller, P: circular pipe, P ₁ : circle Non-product part of the pipe, P ₂ : Product part of the circular pipe, 1: Deformation prevention mold, 3: Chuck (movement prevention mold), 4: Roller (drawing tool).

Claims (1)

[Scope of Claims] 1. In a circular pipe neck drawing method in which a drawing tool is pressed against a rotating circular pipe to reduce the diameter of the end of the circular pipe, No mold is inserted into the product part, but a deformation prevention mold for preventing drawing deformation is inserted only into the non-product part provided at the end of the circular tube, and the end of the circular tube is axially The end surface of the circular tube is brought into contact with the movement prevention mold so that it does not move along the curve, and in this state, the circular tube is rotated and a drawing tool is applied to the boundary between the product part and the non-product part of the circular tube. A circular tube characterized in that the boundary portion is squeezed by reciprocating in the axial direction of the circular tube while being pressed, and then the minimum diameter portion of the squeezed portion of the circular tube is cut to remove the non-product portion. Mouth squeezing method. 2. In the method of drawing a circular tube by pressing a drawing tool against a rotating circular tube to reduce the diameter of the end of the tube, do not insert the mold into any part of the circular tube other than the end. Insert a deformation prevention mold to prevent narrowing deformation only at the end of the circular tube, and also prevent movement of the end surface of the circular tube so that the end of the circular tube does not move along the axial direction. The pipe is brought into contact with a mold, the pipe is rotated in this state, and the pipe end is squeezed by moving the drawing tool back and forth in the axial direction of the pipe while pressing the pipe end of the pipe. How to draw the mouth of a circular tube.