JP3368291B2 - Rolling processing method of tubular square screw body - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tubular square threaded body in which a square metal thread having a high accuracy and a high strength is required in the axial direction over substantially the entire length of a thin metal tube and is rolled for a sufficiently long time, and the tubular corner. It belongs to the field of adjuster structures that use a screw body as a screw shaft, and the technology of rolling square screws into thin-walled metal pipes.

[0002]

2. Description of the Related Art Conventionally, a square screw (including a trapezoidal screw; the same applies hereinafter) has been used as a so-called motion screw when a driven body is linearly moved or a moving amount is adjusted by a screw mechanism. It is known to be small and suitable, and is suitable as a screw shaft of a so-called adjuster structure.

From the viewpoints of reducing the weight of the screw shaft, saving the material, and facilitating the screw forming technique, it is desired to realize a tubular square screw body in which a square screw is rolled. However, at present, we do not know a tubular square screw body that requires a highly accurate and strong square screw in a thin metal tube in the axial direction and is rolled for a sufficiently long time. At present, the thread rolling technique is widely used as a method that is inexpensive and suitable for mass production, but it is mainly performed on solid steel rods.

As a method of rolling a screw on a hollow thin metal tube, only a cap of a bottle, a threaded portion of a light bulb, etc. are used.

[0005]

Conventionally, as a screw shaft of an adjuster structure that bears a large axial force, a square screw shaft obtained by threading a square screw into a solid steel rod is generally used. There is. Therefore, the weight is large in proportion to the outer diameter and the axial length of the screw shaft. If the screw shaft is made of a hollow tubular body, weight can be reduced and material can be saved. Further, it is more desirable that the square screw can be formed by the rolling method of the tubular body, but at present, as described above, the technique for rolling the round screw into the small caps is the best. No technique has emerged for providing a tubular square screw body having load-bearing performance and accuracy that can be used as the above-mentioned motion screw (screw shaft for adjuster) and sufficient effective length in the axial direction.

[0006] Because the current thread rolling process technology is either thread rolling with a flat die or thread rolling with a round die, the die has the entire length of the effective axial length of the screw to be manufactured. It has a structure in which a thread extending up to 10 mm is formed, and all the thread rolling is completed at a stroke while the material rod to be processed makes at least one rotation. If this technology is applied as it is to try to roll a square screw into a metal tube, the elongation of the material at the time of processing cannot be absorbed, and especially thin materials are easily stretched,
It is believed that it cannot consistently provide strong screws.

[0007] If a screw shape that is hard to be stretched out is used, or if a material having excellent extensibility is used, it may be possible to prevent the stretched out to a certain extent. The length is extremely limited, and the material (material) is relatively freely selected as the screw shaft of the adjuster structure for various applications, and the tubular square screw body that can withstand a large load over the necessary and sufficient effective length is provided. It means that it cannot be rolled with high precision.

Further, when a square screw is rolled on a tubular body, it is necessary to improve the working accuracy by devising the tubular body so as not to be crushed by a large working force at the time of rolling. It becomes an issue. Therefore, the object of the present invention is to
For example, the effective length is long so that it can be used as a screw shaft for adjuster structures such as multi-stage stockers for agriculture.
(EN) It is possible to provide a tubular square screw body which is highly accurate and has been rolled to withstand a large load (bending and axial force), and an adjuster structure using the tubular square screw body.

[0009] Another object of the present invention is to provide a method for rolling a rectangular tubular screw body, which is suitable for mass production, is low in cost, and has high accuracy.

[0010]

According to a first aspect of the present invention, there is provided a method for rolling a tubular square screw body, wherein a long thin metal tube which is a workpiece is supported at both ends by a rotary chuck. At least equal to a thin metal tube and bisected
The thin-walled metal tube is inserted into a core shaft, and one end of the thin-walled metal pipe is integrally clamped and supported by the rotary chuck with the core shaft, and the other end is a free end. The shaft should be integrally and concentrically rotated by the rotary chuck, and the outer peripheral surface of the core shaft should be provided with a square screw shape as a base of a square screw to be formed into a thin metal tube. A plurality of rolling rollers having a single mountain shape, which are arranged in an order suitable for stepwise forming from roughing to finishing, are brought into radial contact with the outer peripheral surface of the thin metal tube. , Each rolling roller is pressed against the thin-walled metal pipe in an arrangement following the square screw shape of the core shaft, and according to the rotation of the thin-walled metal pipe, the rolling roller is equal to the pitch of the square screw by the rotary chuck of the thin-walled metal pipe. Support
It is characterized in that the square screw is rolled on the thin-walled metal pipe by relatively moving in parallel to the free end from the fixed end. According to the invention described in claim 2, in the method for rolling a tubular rectangular screw body according to claim 1, an attempt is made to form the core shaft into a thin-walled metal tube that a rotary chuck that clamps and supports the thin-walled metal tube has. A core shaft having a square screw shape as a base of the square screw to be formed on the outer peripheral surface thereof, and a core shaft of the rotary chuck on the free end side are connected to each other so as to be relatively rotatable on the same center line, After rolling the square screw to the thin metal tube, release the rotary chuck that tightens and supports the thin metal tube,
Reversely, the thin metal tube is clamped and supported by the rotary chuck on the free end side, and the core shaft provided with the square screw shape that is the base of the square screw and the thin metal tube are rotated in opposite directions to separate them. Is characterized by.

[0011]

[0012]

[0013]

[0014]

Embodiments and Examples of the Invention With the rolling method of the present invention,
As shown in FIG. 1, the tubular square screw body 1 to be manufactured has an axial direction from the upper end of a thin metal pipe 10 having a total length L of 200 mm so as to be used as a vertical screw shaft of an adjuster structure. The square screw 2 is rolled in the effective length m = 150 mm. More specifically, this tubular square screw body 1 has a square screw 2 in the longitudinal direction of a thin metal tube 10 made of stainless steel having an outer diameter of 32 mm and a wall thickness of 1 mm.
It is a rolled product. A screw mechanism is configured by screwing a nut 9 having the same screw specifications into the square screw 2. The nut 9 is attached to the tip of the protective tube 19. Either one of the tubular square screw body 1 and the nut 9 is rotated and the other rotation is fixed (stops rotation).
Then, the screw movement causes relative movement in the axial direction of the screw shaft.

An example of the specifications of the square screw 2 of the tubular square screw body 1 is a substantially trapezoidal screw thread having a screw pitch of 5 mm and a screw thread height of 1.5 mm. Axial load capacity is
The limit load is 1350 kg in the practical strength test. Since the practical load when used for the adjuster structure is 350 kg, it means that the safety factor is nearly four times higher. The mode in which the tubular rectangular screw body 1 is used as the screw shaft of the adjuster structure is as shown in FIG.
In addition to the case of fixing and standing vertically, as shown in FIG. 2, the lower end of the tubular square screw body 1 is drawn and fixed to a small-diameter cap having a spherical body 4, and the spherical body 4 is fixed to the spherical concave portion of the ground plate 3. 5
It is also used in a structure that is freely fitted and supported. Alternatively, as shown in FIG. 3, a cap 6 having a large-diameter spherical body 4 is fitted and fixed to the lower end of the tubular square screw body 1 and is freely supported by the installation plate 3, or a spherical body without a ground plate is directly grounded. ,
Alternatively, as shown in FIG. 4, a spherical concave portion 7 may be formed at the lower end of the tubular rectangular screw body 1 and the spherical concave portion 7 may be fitted into the spherical projection 8 of the ground plate 3 to be used in a freely supporting structure. By the way, Fig. 4
The spherical concave portion 7 can be easily formed by forming the tubular square screw body 1 at the lower end thereof by a roll forming technique.

Next, manufactured by the rolling method according to the present invention.
An example of an adjuster structure using the tubular square screw body 1 is shown in FIG. Specifically, it is a multi-stage stocker for agriculture. Upper frame plate 1 horizontally fixed to the device frame 11
2 and a lower frame plate (not shown), four screw shafts 13 using the above-mentioned tubular square screw body 1 are vertically arranged in parallel at four corners and rotatably installed. There is.
Although only one stage is shown in FIG. 5 between the upper and lower frame plates, a moving plate 15 having nuts 14 (made of engineering plastic) screwed into the screw shafts 13 to form a screw mechanism is required in the vertical direction. It is installed by the number. On the other hand, a drive motor 16 is installed on the upper frame plate 12, and the drive motor 16 and the pulley 17 of each screw shaft 13 are commonly connected by a belt 18 (or a chain, a timing belt, or the like).

Therefore, when the drive motor 16 rotates the screw shafts 13 in the common direction at the same speed, the moving plate 15 is moved in parallel in the vertical direction by the screw movement with the nut 14, and the multi-stage stocker is moved. Exert function. Next, a method for rolling the rectangular tubular screw body according to the invention described in claim 1 will be described.

The essential points of the rolling method of the tubular square screw body 1 are:
First, as shown in FIG. 6, the thin-walled metal tube 10 that is a workpiece is inserted into the core shaft 20, and one end of the thin-walled metal tube 10 is connected to the core shaft 20 by a chuck 21 (air chuck). Tighten and fix together. The other end can be supported by the air chuck 22 on the opposite side as shown in FIG. 7, but it is a free end without being chucked during the rolling process. The air chuck 22 on the opposite side also has a second core shaft 20 ', but is relatively rotatably connected to the core shaft 20 via a needle bearing 23 to have a structure of substantially supporting both ends. ,
Therefore, the thin metal tube 10 and the core shafts 20 and 20 'are integrally rotated on the same center line.

Secondly, on the outer surface of the core shaft 20, both corners of the screw thread, which form the base of the square screw 2 having the above-mentioned size specifications to be formed in the thin metal tube 10, are R-shaped (see FIG. 11). (See)). Thirdly, in the thin metal tube 10, the square screw 2 is formed step by step from roughing to finishing. As a means, large from R-like processing to the upper finish suitable for performing a square thread 2 stages, with a single mountain shape (see FIG. 9) a plurality of rolling rollers 24A to 24D, FIG. As illustrated in FIG. 8, the thin-walled metal pipe 10 is installed in a stepwise and continuous arrangement in the radial direction with respect to the outer peripheral surface of the thin metal pipe 10. And
The rolling rollers 24A to 24D are pressed against the thin-walled metal pipe 10 so as to follow the screw shape 20a of the core shaft 20, and the rolling rollers 24A to 24A to
24D according to the pitch of the square screw 2 of the thin metal tube 10
Rolling is carried out by relatively moving from the fixed end side (FIG. 6 side) supported by the rotary chuck to the free end side (FIG. 7 side).
It

Incidentally, each of the above-mentioned rolling rollers 24A-2
FIG. 11 shows a procedure of stepwise forming the square screw 2 on the thin metal tube 10 by 4D from large R-shaped processing to top finishing processing.
Shown in A to D. In short, in FIG. 11A, the large R-shaped processing roller 24A pushes the tube wall of the thin-walled metal tube 10 into a shape in which the tube wall of the thin-walled metal tube 10 is bent in an R shape toward a straight thread groove in the thread shape 36 of the core shaft 20. In FIG. 11B, the bottom of the thread groove is further pushed to the left and right, and in FIG.
Holds the thread portion flat and flat, and further reduces the radius R of the bottom corner portion of the thread groove to make it square, and in FIG. 11D, the upper finishing roller 24D finishes almost trapezoidal. In this way, each rolling roller 24 </ b> A to 24 </ b> D sequentially completes the shape of the square screw 2 in the thin metal tube 10 by following the screw shape 36 of the core shaft 20. At this time, since the other end (the end on the side of FIG. 7) of the thin-walled metal pipe 10 is a free end, there is a degree of freedom to follow the above-mentioned pushing and bending of the pipe wall, and an inconvenient out-of-stretch phenomenon occurs. do not do.

Fourthly, as a step after rolling the square screw 2 on the thin metal tube 10, first, the clamping and fixing of the core shaft 20 and the thin metal tube 10 by the chuck 21 is released, The slave shaft 20 is supported only by one chuck 21 (Fig. 6), the thin-walled metal tube 10 is supported by the other chuck 22 (Fig. 7), and both are rotated in the opposite directions so that the screw movement is performed as shown in Fig. 10. Utilizing and separating (invention of Claim 2 ).

Each step of the rolling method of the tubular rectangular threaded body described above is specifically carried out mechanically by the mechanical device illustrated in FIGS. 12 and 13. An air chuck 21 on the right side in FIG. 12 (see FIG. 6 for details) for integrally fastening and fixing the thin metal tube 10 and the core shaft 20 is installed on a box-shaped frame 25 having a rotary shaft 27 on the right side. Left and right 2
It is rotatably supported by individual bearings 26, 26. This air chuck 21, as shown in FIG.
The core portion 20 fitted concentrically and the outer periphery of the end portions of the thin metal tube 10 are fixed by the chuck portion 21a so as to rotate integrally.

The air chuck 22 on the left side in FIG. 12 has a movable base of a linear bush 31 which is fixed at one end on the left side frame 29 and slides along two parallel linear shafts 30 protruding leftward. It is attached to the rotary shaft of the geared motor 34 attached to 33, and is arranged to face the right side air chuck 21 on the same center line. The air chuck 22 is provided with a short core shaft 20 'as is clear from FIG. A shaft hole 35 formed in the inner tip of the right core shaft 20 is fitted to the outer periphery of the needle bearing 23 attached to the inner end of the core shaft 20 'so that both shafts are in series on the same center line and It is a structure that can be freely rotated. However, before connecting the left and right core shafts 20 ′ and 20 , the thin metal tube 10 is fitted on the outer peripheral surface of the right long core shaft 20 . Next, the movable table 33 of the geared motor 34 is moved to the right in the figure, the core shafts 20 and 20 'are connected in series, and the movable table 33 is locked by a lock mechanism provided on the movable table 33, though not shown. The position of 33 is fixed and the rolling process is set. On the outer peripheral surface of the core shaft 20 ′, a square screw shape 36 that is a base of the square screw 2 (see FIG. 1) to be rolled into the thin metal tube 10 is formed.

Between the left and right frames 29 and 25, two pieces are arranged in parallel with the center line shared by the left and right air chucks 22 and 21 and symmetrically arranged on both sides of the center line. A plurality of feed screw shafts (ball screw shafts) 40, 40 are installed, and both ends thereof are bearings 41 and 4.
It is rotatably supported by 2. A driven gear 43 having the same number of teeth is attached to the right end of each feed screw shaft 40, and these are connected with a sun gear 44 fixedly attached to the rotary shaft 27 of the air chuck 21 on the right side by a common gear train. The feed screw shaft 40 is adapted to rotate in a common direction at the same rotation speed.

Another gear 45 is attached and fixed to the rotary shaft 27 of the right air chuck 21, and a driving pinion 47 of a geared motor 46 attached to the right side surface of the frame 25 is meshed with the gear 45. Therefore, the right air chuck 2 is driven by the right geared motor 46.
1 is rotated, and while maintaining a constant relationship with the rotation speed and rotation direction of the air chuck 21, each feed screw shaft 4
0 is rotated in the common direction at the same speed, which enables the rolling process of the square screw 2 by the rolling rollers 24A to 24D. The left and right geared motors 34 and 46 can perform synchronous operation in the same direction at the same speed, and can also rotate in opposite directions.

A roller moving table 51 is attached to each of the feed screw shafts 40.
The feed nut 50 (ball nut) is screwed in. The roller moving base 51 moves in the left-right direction in FIG. 12 by the screw movement of the feed screw shaft 40 and the feed nut 50. In other words, the moving speed of the roller moving table 51 and the rotation of the core shaft 20 supported by the air chuck 21 and the thin-walled metal tube 10 as the workpiece are the same as the rotation of the square screw 2 and the screw advance (pitch). It is possible to operate by setting the relationship.

On the roller moving table 51, as shown in FIG. 13, the core shaft 2 supported by the air chuck 21.
0 and the thin-walled steel pipe 10 are radially arranged in four directions at right angles, and the above-mentioned four rolling rollers are provided for progressively rolling the square screw 2 from large R-shaped processing to finish finishing. 24A to 24D are arranged. Each rolling roller 2
4A to 24D are individually rotatably supported by the leading end of an arm 52 provided so as to be movable only in the radial direction by a guide means provided on a roller moving base 51.

By the way, the rolling roller 24 for finish finishing
D is illustrated in FIG. Shaft 2 at the tip of the arm 52
4a, a roller 24c that rotates around a shaft 24b inclined by the lead angle θ of the square screw 2 is installed.
Although the other rolling rollers 24A to 24C have the same configuration, they are arranged so as to equally divide the screw groove and the screw pitch so that the rolling process can be performed stepwise.

Each of the arms 52 is provided with a roller moving table 51.
, The output shaft of the drive cylinder 53 installed in the same radial corner as the rolling rollers 24A to 24D is connected by the toggle link mechanism 54, and the output of the drive cylinder 53 is boosted to roll the square screw 2. The rolling rollers 24A to 24D are individually pressed against the thin-walled steel pipe 10 with a force required for processing. Each drive cylinder 53 is remotely controlled by a controller (not shown). In this embodiment, the rolling roller has four stages, but the number of stages is not limited to this, and the number of stages is set according to the screw diameter.

As an example, the rolling method of the tubular square screw body 1 by the above-described mechanical device of FIGS. 12 and 13 is carried out as follows. A thin metal tube 10 made of stainless steel having an outer diameter of 32 mm, a wall thickness of 1 mm and a length of 400 mm is used as a work piece. The thin metal tube 10 is fitted on the outer peripheral surface of the core shaft 20 on the right side in FIG. 12, and is integrally tightened and fixed by the air chuck 21 on the right side, and then the air chuck 22 is moved to the right side together with the moving table 33 on the left side. Move and both core axes 2
Set 0 and 20 'by fitting and connecting. Core axis 2
No. 0 has an outer diameter of 30 mm, and a square screw 2 (screw pitch 5 mm, thread height 1.5 mm) to be manufactured over its entire length.
Has a square screw shape 20a as a base.

The geared motor 46 is started to rotate the air chuck 21, the thin-walled metal pipe 10 supported by the air chuck 21, and the core shaft 20 counterclockwise at a speed of 90 rotations per minute. The roller moving table 51 is 5 mm per rotation of the thin metal tube 10.
It is moved to the left in FIG. The thin metal pipe 10 has square screws 2 with left and right ends having dimensions (about 50 mm each) necessary for chucking by the air chucks 22 and 21.
Is rolled.

When the rolling process progresses to a predetermined portion, each drive cylinder 53 operates and each rolling roller 24A to 24D.
Retracts away from the thin metal tube 10. At the same time, the air chuck 21 releases the support between the thin metal tube 10 and the core shaft 20. Immediately thereafter, the right geared motor 46 is reversely driven, and the roller moving base 51 is moved rightward to the original position. When the roller moving base 51 returns to the original position, the geared motor 46 is stopped.

The air chuck 21 is a thin metal tube 1
When 0 is released, the air chuck 22 on the left side in FIG.
The end portion of the thin-walled metal tube 10 is strongly supported so as to be fastened to the outer periphery of the core shaft 20 'therein, and the movable table 33 is unlocked, and the geared motor 34 at the left position in the figure is also released.
To rotate left. Then while the screw motion of the core shaft 20 and the tubular angles threaded body 1 of the reverse rotation driven right moving base 33 of the geared motor 34 is moved to the left in FIG. 12 along the linear shaft 30, core shaft 20 and the tubular square screw body 1 are sequentially removed. At the stage of complete separation as shown in FIG. 10, the geared motor 34 is stopped, the left air chuck 22 is released, and the product is discharged to the outside of the apparatus.
The movement of the moving base 33 stops when the tubular square screw body 1 comes out of the core shaft 20, so that the moving base 33 is manually moved to the left for the interval required for discharging the tubular square screw body 1.

As another method for extracting the rolled tubular square screw body 1 from the core shaft 20, the rolling rollers 24A to 24A are driven by the respective drive cylinders when the rolling process is completed.
24D is retracted away from the thin metal tube 10. After that, when the right geared motor 46 is reversely driven to move the roller moving base 51 to the original position, the geared motor 46 is stopped and the support of the thin metal tube 10 and the core shaft 20 by the air chuck 21 is released. It

Then, the movable table 33 is unlocked, the thin metal tube 10 is supported by the air chuck 22 on the left side together with the core shaft 20 ', and the left side of the geared motor 34 is rotated to the right to stop the rotation. Due to the screw movement with the core shaft 20, the moving base 34 of the geared motor moves to the left along the linear shaft 30, and the tubular square screw body 1 sequentially comes out of the core shaft 20.

The air chuck used in this embodiment is capable of supporting a small diameter, easy to support and release automatically, and excellent in operability. Air is supplied to the outer end of the rotary shaft 27 in a rotatable relationship with the rotary shaft 27.
The air valve of the connector 28 fixed to the frame 25 is used to facilitate opening and closing of the rotating air chuck 21. In addition, the connector 28 is connected to the moving table 3 on the left side.
The same operability is ensured by attaching to No. 3 and supplying the same air as described above. However, the chucking means is not limited to the air chucks 21 and 22, and it is also possible to adopt a hand chuck with cost priority.

Next, the tubular square screw body 1 manufactured as described above is cut at its center and divided into two halves. The effective screw length shown in FIG. 1 is 150 mm and 50 mm at one end.
A feed screw shaft for an adjuster having a non-threaded portion can be obtained. In the above embodiment, the outer diameter is 32 m.
Although the work piece (thin metal tube) having a length of m and a length of 400 mm has been described, the length of the feed screw shaft 40, the air chuck 2
By changing the diameters 1 and 22 that can be supported and the core shaft 20, it is possible to easily obtain tubular tubular bodies 1 having different effective screw diameters and effective screw lengths.

Further, by cutting the threaded portion generated at one end, a tubular square screw body 1 having a long effective length and having a screw formed over its entire length can be obtained.

[0039]

INDUSTRIAL APPLICABILITY The tubular rectangular screw body manufactured by the rolling method according to the present invention is sufficiently used as a screw shaft for an adjuster structure as a load moving device accompanied by vertical movement of a multi-stage stocker for agriculture. It has a possible effective length, high accuracy, and load-bearing capacity to withstand a considerable load. Therefore, the use of this tubular square screw proof contributes to the weight reduction and material saving of the adjuster structure. In addition, this method of rolling a tubular square screw body is suitable for mass production, and the square screw can be rolled into a thin metal tube at low cost.

[Brief description of drawings]

FIG. 1 is an elevational view showing an example of use of a tubular square screw body.

FIG. 2 is an elevational view showing a different usage example of the tubular square screw body.

FIG. 3 is an elevational view showing a different usage example of the tubular square screw body.

FIG. 4 is an elevational view showing a different usage example of the tubular rectangular screw body.

FIG. 5 is a perspective view showing an example of an adjuster structure.

FIG. 6 is a detailed structural view of a portion A in FIG.

FIG. 7 is a detailed structural view of a B part in FIG.

FIG. 8 is a detailed structural view of a portion C in FIG.

FIG. 9 is a detailed structural view of a rolling roller.

FIG. 10 is an explanatory view showing a separated state of the core shaft and the tubular square screw body.

11A to 11D are process drawings showing the progress of the rolling process of the rectangular screw body.

FIG. 12 is a plan view of a main part of a mechanical device that performs a rolling process for a tubular rectangular screw body.

FIG. 13 is a view on arrow D-D of FIG. 12;

[Explanation of symbols]

10 Thin-walled metal tube Double-headed screw 1 Tubular square screw body 9 nuts 13 screw shaft 14 nuts 16 Drive motor 20 Core axis 20 'core shaft 21 Air chuck 22 Air chuck 20a Base square screw shape 24A Rolling roller 24D Rolling roller

Claims (2)

(57) [Claims] 1. A long thin metal tube which is the workpiece, is supported at both ends to the rotary chuck, inserting into at least the thin metal tube and the core shaft which can be divided in equal lengths, One end of the thin-walled metal pipe is clamped and supported integrally with the core shaft by the rotary chuck, and the other end is a free end, and the thin-walled metal pipe and the core shaft are integrally concentric by the rotary chuck. Rotate, the outer peripheral surface of the core shaft is provided with a square screw shape that is the base of the square screw to be formed into a thin-walled metal pipe, and the square screw is formed in stages from roughing to finishing Arranged in an order suitable to do, a plurality of rolling rollers having a single mountain shape, radially contact the outer peripheral surface of the thin metal tube, each rolling roller of the core shaft Pressed against a thin metal tube with an arrangement that follows the shape of a square screw Rolling a square thread in parallel to move relative to the free end direction from a fixed end which is supported by the rotary chuck equally thin metal tube the rolling roller to the pitch of the square thread in accordance with rotation of the thin metal tube into the thin-walled metal tube A method for rolling a tubular square screw body, the method comprising forming. 2. A core shaft having, on its outer peripheral surface, a square screw shape serving as a base for a square screw to be formed into a thin metal pipe, which is included in a rotary chuck that fastens and supports a thin metal pipe, The core shaft of the rotary chuck on the free end side is connected to the core shaft so that relative rotation is possible on the same center line, and after the square screw is rolled on the thin metal pipe, the thin metal pipe is clamped and supported. The rotating chuck on the free end side to tighten and support the thin-walled metal tube, and rotate the core shaft and the thin-walled metal tube in the opposite direction, which has the square screw shape as the base of the square screw. The method for rolling a tubular square screw thread according to claim 1, characterized in that the two are separated.