JP2001009524A - Manufacture of cylinder element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylindrical element manufacturing method wherein an equipment cost and a set-up space can be reduced while manufacturing cost by a set-up exchange operation, etc., can also be reduced. SOLUTION: This cylindrical element manufacturing method is composed of a working process wherein a bend work is performed at one end part 91a and the other end part 91a of a metal plate 9a by using a press having an end part bending die, and one end part 91a and the other end 91a are bent so as to oppose each other at a given bending height for obtaining an intermediate product 9b, whose both ends are bend processed. The method is also composed of a roll molding working process wherein a bend work is performed to the processed intermediate product 9b by using a roll molding machine in a way that the both ends 91b, 91d are approaching each other, for obtaining a cylindrical element 9 having a slite extending along an axial direction P.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a tubular body used for manufacturing a metal pipe.

[0002]

2. Description of the Related Art Generally, when manufacturing a metal tube, for example, a metal plate 9a shown in FIG. 9 is manufactured as a circular cylindrical body 9 having a slit e extending along the axial direction P, and then a slit is formed. e, the opening end surfaces 92, 92 of the two end portions 91, 91 opposed to each other are held against each other to hold the slit e in a closed state, and the opening end surfaces 92, 92 are welded together in the axial direction P to be integrated. It is known to obtain a tube by conversion.

[0003] As a method of manufacturing the cylindrical body 9, for example, as shown in FIG. 8, a metal plate 9 a is subjected to a roll forming process to obtain a substantially circular cylindrical intermediate body 9.
The cylindrical body 9 was obtained by subjecting a1 (see FIG. 8) to a circular processing step using a shrink press 4D (see FIG. 12).

[0004] Here, the substantially circular cylindrical intermediate member 9a1 obtained in the above-mentioned roll forming step is provided with slits e from two opening end faces 92 opposing each other via a slit e.
There are side end portions 91a, 91a which are not formed in the shape of an arc along the circumferential direction and are flat regions S. The flat area S is about 5 mm to 10 mm when the outer diameter is about 120 mm, depending on the outer diameter of the tubular intermediate 9a1.

The flat region S is reduced in diameter by a semi-circular concave lower mold 4a and a semi-circular concave upper mold 4b of a shrink press 4D in a circular processing step which is subsequently performed, and is formed in a circumferential direction. It is corrected to a circular shape in the process of making the whole area circular.

[0006]

The shrink press 4D used in the circular processing step in the conventional method of manufacturing a cylindrical body requires a high processing pressure (about 40 tons or more), so that the equipment becomes large, It is disadvantageous in terms of equipment cost and installation space. In addition, the larger the size, the slower the operating speed, and the longer the time required for the compression cylinder processing step.

[0007] Further, the lower half semi-circular recessed die 4a and the upper semi-circular recessed die 4b to be mounted on the shrink press 4D are arranged so as to wrap the substantially circular cylindrical intermediate body 9a1 from the outer periphery thereof. It is large because it is a circular shape.

The semi-circular concave lower mold 4a and the semi-circular concave upper mold 4b require different mold sizes for a plurality of types of circular cylindrical bodies having different outer diameters. Each time a kind of circular cylindrical body is manufactured, a setup change operation for changing to a suitable mold size is required.

Here, in the case of the conventional method for manufacturing a circular cylindrical body, there is still room for improvement in terms of equipment cost, installation space, and manufacturing cost due to setup change work.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a method of manufacturing a tubular body that can reduce equipment costs and installation space, and can also reduce manufacturing costs due to setup change work and the like. I do.

[0011]

According to a method of manufacturing a cylindrical body of the present invention, one end and the other end of a metal plate are subjected to bending using a press provided with an end bending die. The other end is bent so as to face each other at a predetermined bending height to obtain an intermediate product having both ends bent, and a bending process is performed on the processed intermediate product using a roll forming machine,
And a roll forming step of obtaining a cylindrical body having slits extending along the axial direction by bending the circular shape so that both ends are close to each other.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method for manufacturing a cylindrical body according to the present invention comprises the steps of sequentially bending both ends of a metal plate having a developed length of a cylindrical body to be manufactured and a roll forming step. By applying, a cylindrical body having a slit extending along the axial direction is manufactured.

The metal plate is formed by using a press equipped with an end bending die in the end bending step, and setting one end and the other end (both ends of the developed length) to a predetermined bending height in parallel with the axial direction. An intermediate product that has been bent at both ends (a bent plate at both ends) by being bent so as to face each other at a (predetermined inclination angle)
Molded into

In the subsequent roll forming process, the intermediate product having both ends bent is carried (input) into the roll forming machine from one end or the other end where the intermediate product is bent, and the entire region along the circumferential direction is formed. .

[0015] Therefore, the intermediate product having both ends bent is:
A cylindrical body having a slit that is bent in a circular shape so that one end and the other end are close to each other, and the side end of the one end and the side end of the other end are open ends facing each other in the circumferential direction, and extend in the axial direction. Molded as

As described above, the method for manufacturing a cylindrical body according to the present invention is a large-sized facility having a high processing pressure used in the compression cylindrical processing step performed following the roll forming processing step in the conventional manufacturing method. There is no need for a shrink press and a split semi-circular concave lower mold and a semi-circular concave upper mold.

Furthermore, both ends are quickly bent using a shrink press and a press having an end bending die which is smaller in size and lower in processing pressure than the half-circle concave lower die and the semi-circular concave upper die. After obtaining the intermediate product, a cylindrical body is manufactured by performing a roll forming process.

Therefore, the method for manufacturing a cylindrical body according to the present invention is disadvantageous in terms of equipment cost and installation space as in the case of using a conventional shrink press having a high working pressure, and The operation speed can be prevented from being reduced.

The end bending mold comprises a concave mold and a convex mold. The concave mold and the convex mold have a cavity width corresponding to the developed length of the metal plate having the developed length of the cylindrical body to be manufactured. A configuration held so as to be adjustable and movable can be used.

The end bending die is composed of a concave type and a convex type.

The end bending die may be configured so that the cavity width corresponding to each of a plurality of metal plates having different development lengths of the cylindrical body can be adjusted and moved.

In this case, when manufacturing a plurality of types of cylindrical bodies having different outer diameters, the same concave and convex molds are formed by using a metal plate having a developed length of the cylindrical body to be manufactured. By adjusting and moving to the cavity width corresponding to the length, the work of changing the conventional half-circular concave lower mold and the semi-circular concave upper mold of the conventional shrink press into different mold sizes is performed at all. You don't have to.

Accordingly, the manufacturing cost can be reduced because the setup change operation is not required. Further, in the case of a mass production system installed and used in a production line, a cylindrical body can be produced at a speed about three times faster than in the case of the conventional production method, and the production efficiency can be greatly improved.

The convex shape is arranged in a state of being divided into two parts at a predetermined interval in the horizontal direction, and is fixed to one of the first divided convex shape and the first divided convex shape. It can be constituted by a second divided convex type which is movably held in a direction of moving and approaching and moving away.

One of the first fixedly arranged and held parts is divided into two parts at a predetermined interval in the horizontal direction.
It can be constituted by a divided concave mold and a second divided concave mold which is horizontally moved with respect to the first divided concave mold and held so as to be movable in a direction of approaching and moving away from the first divided concave mold.

The second divided convex type and the second divided concave type can be set so that they can be horizontally moved simultaneously in the same direction at the same interval by a synchronizer.

As a driving source for horizontally moving the second divided convex type and the second divided concave type, for example, a hydraulic cylinder, an electric motor or the like can be used.

As the press, a sensor for detecting the size of the metal plate (development length of the cylindrical body) when the metal plate is conveyed and loaded into the cavities of the first divided concave type and the second divided concave type,
Receiving the value (data) detected and transmitted by the sensor, comparing and calculating various command values stored in advance, and driving a drive source for horizontally moving the second divided convex type and the second divided concave type by a predetermined amount. Alternatively, it is possible to use a device provided with a control unit for simultaneously moving and positioning the second divided convex mold and the second divided concave mold to a position (suitable) corresponding to the size of the metal plate.

In this case, various sizes of cavities can be quickly adjusted to correspond to the metal plate sizes corresponding to the plurality of types of circular cylindrical bodies, and the process can be immediately started.

Therefore, there is no need to change the mold itself as in the conventional case, and the cost of equipment and the manufacturing cost due to the changeover work can be greatly reduced as compared with the conventional case.

[0031] Between the first split concave mold and the second split concave mold,
A transfer device for loading and unloading the metal plate and the processed intermediate product can be provided at a position where the processing of the metal plate by the concave and convex shapes is not hindered.

The end-bending mold has a configuration in which, for each of a plurality of metal plates having different development lengths of the tubular body, the metal plate is changed into a concave shape and a convex shape having a cavity width corresponding thereto. Can also be used.

In this case, although the end bending die needs to be set up and changed, the lower half of the semicircular concave portion and the upper half of the semicircular concave portion which are used by being attached to the conventional shrink press are used. Compared with the case where the mold is changed, the size is small, so that the change work can be completed quickly and easily, and the working time can be reduced and reduced.

In the bending process at both ends, when a flat metal plate is bent, a slight bending is performed from the position of the end surface (corresponding to the opening end surface forming a slit extending in the axial direction of the cylindrical body) at both ends. Bend to a slight bending height in width.

For this reason, for example, a thickness of about 1 mm to about 1.
For a 6 mm metal plate, the bending target width (hereinafter referred to as bending allowance) is 1 mm to 6 mm, and the metal plate only needs to be bent upward by 0.1 mm to 1.2 mm with respect to a flat lower surface, for example, and is processed. A low pressure press can be used.

The bending allowance is 1 mm to 6 mm, preferably 2 mm to 4 mm. The reason for this is that if the bending allowance is less than 1 mm, bending becomes difficult, and if the bending allowance exceeds 6 mm, both sides forming slits extending along the axial direction of the cylindrical body in the roll forming process are formed in the circumferential direction. There is a possibility that the processing of the arc shape toward becomes difficult and remains as a flat surface.

Accordingly, if the bending allowance is within the above range, it is easy to bend in the both ends bending step, and the bent both sides are easily formed into an arc shape in the roll forming step.

The bending height for bending upward is, for example, 0.4 mm to 1.0 m for a metal plate having a thickness of about 1.5 mm.
m, and preferably 0.5 mm. The reason for this is that when the bending height is less than 0.4 mm, the slits extending along the axial direction of the cylindrical body after the roll forming process are formed. Is closed, it becomes V-shaped, and a good welding state cannot be obtained.

When the bending height exceeds 1.0 mm, the open ends of both sides forming a slit extending along the axial direction of the cylindrical body having been subjected to the roll forming process are butted prior to welding to close the slit. In this case, an inverted V-shape is formed, and a good welding state cannot be obtained.

Accordingly, when the bending height is within the above range, when the cylindrical body after the roll forming process is welded, when the slits are closed by abutment of the circumferential open ends, a good match is obtained. A welding condition is obtained.

[0041]

(Example 1) As shown in FIGS. 1 and 7, a method for manufacturing a cylindrical body according to Example 1 includes a step of bending both ends of a stainless steel plate 9a and a step of bending the obtained both ends. A description will be given of a case where the rolled plate 9b is subjected to a roll forming process to manufacture the tubular body 9.

The stainless steel plate 9a has a thickness t of about 1.5 m.
m, the length L is about 300 mm, and the width W to be bent into a circle is equivalent to the developed length of the cylindrical body 9 having a predetermined outer diameter value (the state in which the slit e along the axial direction P is closed) to be manufactured. Is what you do.

The method for manufacturing a cylindrical body according to the first embodiment is performed in the order of a bending process at both ends and a roll forming process.

(Both-end Bending Step) In the both-end bending step, as shown in FIG. 2, a both-end bending press (hereinafter referred to as a press) 4 having an end face forming die 1 is used.

The end face forming die 1 is provided with a fixed holding member 50 and a horizontal moving member 51 on a movable table 4c capable of moving up and down the press 4.
Via a fixed holding member 52 and a horizontal moving member 53 to a symmetrically shaped first divided concave mold 2a and a second divided concave mold 2b mounted via the fixed holding member 52 and the horizontal moving member 53. Symmetrical first split convex 3 mounted
a and the second divided convex mold 3b.

The second divided concave mold 2b can be horizontally moved together with the horizontal moving member 51 in a direction approaching and moving away from the first divided concave mold 2a (see arrows X1 and X2) by the horizontal gap adjusting drive unit 2c.

The second divided convex 3b is horizontally movable together with the horizontal moving member 53 in a direction approaching and moving away from the first divided convex 3a (see arrows X1 and X2) by the horizontal gap adjusting drive 3c.

The second divided concave mold 2b and the second divided convex mold 3b
The sensor 2d detects the width W (development length of the cylindrical body 2) of the stainless steel plate 9a put into the first divided concave mold 2a and the second divided concave mold 2b, and receives a value (data) detected and transmitted by the sensor 2d. The horizontal interval adjustment drive unit 2c and the horizontal interval adjustment drive unit 3
c is driven by a predetermined amount, and is controlled by a control unit 2e which instructs a positioning movement in synchronization with the directions of the arrows X1 and X2.

Therefore, the cavity spacing W1 formed by the first divided concave mold 2a and the second divided concave mold 2b and the cavity spacing W2 formed by the first divided convex mold 3a and the second divided convex mold 3b are horizontal. Various controls are performed depending on the driving states of the interval adjustment drive unit 2c and the horizontal interval adjustment drive unit 3c. A hydraulic cylinder can be used for the horizontal interval adjustment drive unit 2c and the horizontal interval adjustment drive unit 3c.

The first split concave mold 2a has an inner bottom surface 20a and an inclined surface 21a inclined upward by about 10 ° from the inner bottom surface 20a (see FIG. 3). The second split concave mold 2b is
And an inclined surface 21 inclined about 10 ° upward from the inner bottom surface 20b
b.

The first split convex 3a has a bottom surface 30a and a bottom surface 3a.
An inclined surface 31a inclined upward by about 10 ° from 0a is provided. The second split convex 3b includes a bottom surface 30b and an inclined surface 31b inclined upward by about 10 ° from the bottom surface 30b.

The press 4 includes a base 4a, four guide columns 4b standing upright from the base 4a, a movable platform 4c horizontally held by the guide columns 4b and held up and down, and a base 4a.
And an upper horizontal mount 4d connected to the top of the guide post 4b. A hydraulic cylinder can be used as the lifting drive 4e.

Next, a description will be given of a case where both ends are bent using the end face forming die 1 and the press 4 configured as described above.

First, the end face molding die 1 is configured such that the first divided concave mold 2a and the second divided concave mold 2b are moved by the movable base 4c of the press 4 with respect to the first divided convex mold 3a and the second divided convex mold 3b at the upper fixed position.
Is held down by a predetermined amount.

The first divided concave mold 2a and the second divided concave mold 2
When the stainless steel plate 9a is conveyed and loaded into b, the width W (development length of the tubular body 2) of the stainless steel plate 9a is detected by the sensor 2d.

The sensor 2d detects the detected value (data)
Is transmitted to the control unit 2e, and the horizontal interval adjustment drive unit 2c and the horizontal interval adjustment drive unit 3c are driven by a predetermined amount based on the result of comparison and calculation by the control unit 2e. Then, the second divided concave mold 2b and the second divided convex mold 3b are automatically positioned and moved relative to the first divided concave mold 2a and the first divided convex mold 3a in the directions of the arrows X1 and X2, and the stainless steel plate 9a is moved. Set to the optimal value for processing.

For this reason, the stainless steel plate 9a corresponding to each of the plurality of types of circular cylindrical bodies can be quickly adjusted in accordance with the cavities of various sizes, and the process can be immediately shifted to the processing step.

The stainless steel plate 9a has a bent end 91
It is formed as a bent plate 9b (see FIG. 1) having both ends b and 91b.

Thereafter, the back surface of the bent plate 9b at both ends is held in a suction state by a depressurized gripping / conveying member (not shown), and is conveyed to the outside of the press 4.

The press 4 operates to hold the end face forming die 1 in an open state in preparation for the next both-end bending process.

Accordingly, in the step of bending both ends in the method of manufacturing the cylindrical body of the first embodiment, there is no need to change the mold itself as in the conventional case. For this reason, as compared with the above-mentioned conventional case, the equipment cost and the manufacturing cost due to the changeover work can be greatly reduced.

(Roll Forming Step) In the roll forming step, a roll forming machine 6 shown in FIG. 4 is used. The roll forming machine 6 includes a main shaft roller 7 held horizontally at a fixed position, two bending rollers 8a and 8b held parallel to the main shaft roller 7 and held at a predetermined interval, and a lifting drive unit 8c. And the lifting platform 8. The elevator 8 can be moved up and down together with the rollers 8a and 8b by the elevating drive unit 8c in a direction approaching and moving away from the main shaft roller 7 (see arrows Y1 and Y2).
It is possible to control the interval h1 with respect to a and 8b.

In the roll forming process following the both-end bending process, the bending rollers 8a and 8b are used to form the bent-end plate 9b together with the main shaft roller 7 into a cylinder having an outer diameter (curvature radius) for roll forming purposes. The elevating position ((the interval position h1 between the rotation center O1 of the main shaft roller 7 and the rotation centers O2 of the bending rollers 8a and 8b) is set in advance together with the elevating table 8 so that the shape body 9 can be processed.

The bent plate 9b at both ends is provided between the main shaft roller 7 which is driven to rotate clockwise and the bending rollers 8a and 8b.
One bent end 91b is inserted in the direction of arrow Z in FIG. At this time, the bending rollers 8a and 8b
Bending plate 9b at both ends
And rotates counterclockwise through.

The bent plate 9b at both ends is processed into a desired curvature at an arc-shaped portion sandwiched between the main shaft roller 7 and the bending rollers 8a and 8b while rotating clockwise.
The bent plate 9b at both ends is processed in the entire circumferential direction into a circular shape while rotating one turn clockwise around the main shaft roller 7 or several turns as necessary, and is formed along the axial direction P. It is formed as a cylindrical body 9 having an elongated slit e.

The cylindrical body 9 stops the rotation of the main shaft roller 7 and lowers the lift 8 together with the bending rollers 8a and 8b in a direction away from the main shaft roller 7, and then moves along the main shaft roller 7 in parallel (see the drawing). In the direction perpendicular to

The cylindrical body 9 (see FIG. 1) manufactured by the pipe manufacturing method of the embodiment 1 has both open end faces (tip end faces) 92, 92 of the peripheral wall portion 90 extending in a circular shape in the circumferential direction having a length of about 5 m.
The shapes are opposed to each other via a slit e having an m width W11.

The cylindrical body 9 is conveyed to the next step and held in a state where the two open end faces 92 are in contact with each other as in the conventional case, and the two open end faces 92 are welded to form a tube. It becomes a product and is used as a container for a catalytic converter.

Therefore, according to the method for manufacturing a cylindrical body of the first embodiment, there is no need to change the mold itself as in the prior art. For this reason, as compared with the conventional case, the equipment cost and the manufacturing cost due to the changeover work can be significantly reduced.

Further, if the method for manufacturing a cylindrical body of Example 1 is used in a mass production type manufacturing line, the cylindrical body can be manufactured at a speed about two to three times faster than in the case of the conventional manufacturing method. And the production efficiency can be greatly improved.

Further, in the production line, a plurality of welding machines (welding devices) are separately installed on the downstream side using the method for producing a cylindrical body of Embodiment 1 to form a plurality of welding lines. One system for manufacturing a body can be shared by a plurality of welding lines, and a cylindrical body having a different size can be supplied to each welding line, thereby improving production efficiency.

(Embodiment 2) The method of manufacturing the cylindrical body of the embodiment 2 is based on the method of adjusting the cavities W1 and W2 mounted on the press 4 in the bending process at both ends used in the embodiment 1. Instead of using the second divided convex mold 3b and the first divided concave mold 2a and the first divided convex mold 3a, they are held at the fixed position in the same manner as the first divided convex mold 3a, and are held by the fixed holding member 51a by the fixed position method shown in FIG. The second embodiment is the same as the first embodiment except that the second divided concave mold 2c and the second divided convex mold 3c held by the fixed holding member 53a are used.

For this reason, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the case of the method for manufacturing a cylindrical body according to the second embodiment,
For each of the plurality of metal plates 9a having different development lengths of the tubular body 9 in the both-end bending process, the first divided concave mold 2a, the second divided concave mold 2c, and the second divided concave mold 2 having cavities W1 and W2 corresponding to them are provided. The one-part convex mold 3a and the second part concave mold 2c require setup change, respectively, but are divided into two semi-circular concave lower molds and a semi-circular concave upper part which are used by being attached to the conventional shrink press. Compared with the case where the mold is changed, the size is small, so that the change work can be completed quickly and easily, and the working time can be reduced and reduced.

Example 3 The method of manufacturing the cylindrical body of Example 3 is based on the method of adjusting the cavities W1 and W2 mounted on the press 4 in the both-end bending process used in Example 1 and adjusting the second divided concave mold 2b. Instead of using the second divided convex mold 3b, one concave mold 2 and one convex mold 3 are held at fixed positions by fixed holding members 50, 51a, 52, and 53a, respectively, to obtain a fixed position method shown in FIG. Except for this, the operation is the same as that of the first embodiment.

Therefore, the same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

In the case of the method for manufacturing a cylindrical body according to the third embodiment,
In the bending process at both ends, for each of the plurality of metal plates 9a having different development lengths of the cylindrical body 9, the corresponding cavity width is changed to the concave mold 2 and the convex mold 3 having the cavities W1 and W2, respectively. Although it is necessary, compared to the case where the semi-circular concave lower mold and the semi-circular concave upper mold that are used by being attached to the conventional shrink press are set up,
Because of the small size, the setup change work can be completed quickly and easily, and the work time can be shortened and reduced.

Further, as compared with the case of the second embodiment, only the setup of the upper and lower concave molds 2 and the convex molds 3 is performed.
Handling operation is simplified.

[0079]

According to the method for producing a cylindrical body of the present invention, a shrink press having a high working pressure and a halving press used in a compression cylindrical working step performed after a roll forming working step in a conventional manufacturing method. No need for the lower semi-circular concave mold and the upper semi-circular concave mold, and perform a both-end bending process using a press having an end bending die smaller than those and having a lower processing pressure. After obtaining a processed intermediate product, a cylindrical body is manufactured by performing a roll forming process.

Therefore, the method for manufacturing a cylindrical body according to the present invention avoids the disadvantage that the equipment becomes large in size as in the case of using a conventional shrink press having a high working pressure, and is disadvantageous in terms of equipment cost and installation space. it can.

The method for manufacturing a cylindrical body according to the present invention comprises a concave and a convex as end bending dies used in the both ends bending step, and the concave and convex dies are formed of a cylindrical body to be manufactured. It is possible to use a configuration in which the metal plate having the developed length is held so as to be adjustable and movable to the cavity width corresponding to the developed length.

In this case, when a plurality of types of cylindrical bodies having different outer diameters are manufactured, the same concave and convex shapes are formed by using the developed length of a metal plate having the developed length of the cylindrical body to be manufactured. By adjusting and moving to the cavity width corresponding to the above, there is no need to perform any work to change the half-circular concave lower mold and the semi-circular concave upper mold of the conventional shrink press into different mold sizes. Only

Further, the bending process of both ends required for manufacturing a plurality of types of cylindrical bodies having different outer diameters can be performed by one end bending die, and the cylindrical body of the type to be manufactured can be processed. A quick switching operation can be performed in response thereto, and the process can quickly shift to bending at both ends.

Therefore, the production cost and the equipment cost can be greatly reduced by eliminating the need for the conventional setup change operation. Furthermore, in the case of a mass production system installed and used in a production line, a cylindrical body can be produced at a speed about three times faster than in the case of the conventional production method, and the production efficiency can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a process of manufacturing a cylindrical body from a stainless steel plate through a bent plate at both ends by a method for manufacturing a cylindrical body according to a first embodiment.

FIG. 2 is a front view showing a both-end bending apparatus used in a both-end bending step in the method for manufacturing a tubular body according to the first embodiment.

FIG. 3 is an enlarged cross-sectional view showing a cross-section of an end face forming die attached to the both-end bending apparatus in FIG. 2;

FIG. 4 is a side view showing a state in which a cylindrical body is manufactured from a bent plate at both ends using a roll forming machine in a roll forming process in the method for manufacturing a cylindrical body according to the first embodiment.

FIG. 5 is a front view showing a both-end bending apparatus used in a both-end bending step in the method for manufacturing a cylindrical body according to the second embodiment.

FIG. 6 is a front view showing a both-end bending apparatus used in a both-end bending step in the method for manufacturing a cylindrical body according to the third embodiment.

FIG. 7 is a process chart showing steps in a method for manufacturing a cylindrical body of Examples 1 to 3.

FIG. 8 is a process chart showing steps in a conventional method of manufacturing a cylindrical body.

FIG. 9 is a perspective view showing a process of manufacturing a cylindrical body from a metal plate via a cylindrical intermediate body by a conventional method of manufacturing a cylindrical body.

FIG. 10 is a front view showing a cylindrical intermediate formed from a metal plate using a roll forming machine in a roll forming process in a conventional method for manufacturing a cylindrical body.

FIG. 11 is an enlarged front view showing both end portions of the tubular intermediate body in FIG. 10;

FIG. 12 is a side view showing a shrink press used in a circular processing step in a conventional method of manufacturing a cylindrical body, a semi-circular concave lower die, a semi-circular concave upper die, and a cylindrical body.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... End face molding die 2a ... 1st division concave mold 2b ... 2nd division concave mold 2c ...
Horizontal interval adjustment drive unit 2d Sensor 2e Control unit 3a First divided convex type 3b Second divided convex type 3c
Horizontal interval adjustment drive unit 4 ... Press 4a ... Base 4b ... Guide column 4c ... Movable table 4d ... Top horizontal mounting table 4e ... Elevation drive unit 6 ... Roll forming machine 7 ... Spindle roller 8 ... Elevation table 8a, 8b ... Roller 9 ... Cylindrical body 9a ... Stainless steel plate 9b ... Bend plate at both ends

Claims (2)

[Claims] 1. A metal plate is bent at one end and the other end using a press having an end bending die so that the one end and the other end face each other at a predetermined bending height. Bending both ends to obtain an intermediate product having both ends bent, and bending the processed intermediate product using a roll forming machine, bending the processed intermediate product into a circular shape so that both ends are close to each other, and axially And a roll forming process for obtaining a cylindrical body having a slit extending along the length of the cylindrical body. 2. The end bending die comprises a concave shape and a convex shape, and the concave shape and the convex shape correspond to the development length of a metal plate having the development length of a cylindrical body to be manufactured. The method for manufacturing a tubular body according to claim 1, wherein the tubular body is held so as to be adjustable in width.