JPH09170615A - Screw shaft and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light and long square screw shaft or trapezoidal screw shaft and manufacturing method thereof. SOLUTION: A member 5-1 (thread member) having a square screw shape or trapezoidal screw shape is wound on the outer surface of a pipe 1 (screw shaft base material) for making the main body part of the square screw shaft or trapezoidal screw shaft and a screw shaft is formed by welding and fixing the screw shaft base material 1 and the thread member 5-1 by arc welding and laser beam welding. In order to produce this screw shaft, a thread member supply device for supplying the thread member, a thread member bending roll, a screw shaft base material supply device for giving a prescribed rotation and feed to the screw base material by the guide of a master screw shaft and for winding the thread member bent by the thread member bending roll to the outer surface of the screw shaft base material and a welding machine for welding and fixing the thread member wound to the screw shaft base material to the screw shaft base material are constituted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a square screw shaft or a trapezoidal screw shaft used in a machine and a manufacturing method thereof.

[0002]

2. Description of the Related Art A square screw shaft or a trapezoidal screw shaft made of ferrous or non-ferrous metal is integrally formed by cutting a bar material with a thread lathe. As another method, there is also a screw shaft made by rolling a bar material.

As a second method, there is an example in which a threaded member is welded to the outer surface of a steel rod or steel pipe in a part of a civil engineering machine to form a screw shaft-shaped component.

[0004]

However, according to the first method described above, although it is possible to make a highly accurate screw shaft for machining, when making a long screw shaft, a large-sized screw cutting equipment is required. Since it is necessary, there is a problem that the cost becomes high. Further, it is difficult to process the pipe material by the rolling method. Since both methods use a bar, there is a drawback that the material cost is higher than that of a pipe. Since the long screw shaft becomes heavy, it was inconvenient to carry and assemble manually. We have not established any technology that can inexpensively supply light and long square screw shafts for medium and light loads.

In the second method, there is an example in which a long screw shaft is formed by a welded structure and is used as a tool for a hole excavator on the ground, but since it is difficult to obtain the screw accuracy, the original screw shaft is combined with a female screw. There was a problem to use as.

[0006] With the aging society approaching, there is a demand for an elevator (home elevator) for an individual house, which has low initial investment, low maintenance cost, and is safe against a fall accident. Since most private houses are three-story or less houses, it is not necessary to use a wire rope hoisting type lifting device for high-rise buildings, and a screw shaft type lifting device with a simple structure seems to be sufficient. The advantages of the square screw shaft type lifting device are: (1) If the lead angle of the square screw is set to a friction angle (10 to 12 °) or less, the car of the lifting device does not drop, which is extremely safe. (2) Since it does not structurally include the factor of dropping, a safety device such as a catcher obligatory for the wire rope hoisting type lifting device is not necessary, and the cost is reduced. (3) Since the structure is simple, it is possible to maintain and manage the device performance without the need of a specialist engineer. Therefore, the maintenance cost is cheap. (4) Since it does not drop, insurance costs are low. And so on.

However, at present, the lifting device for a private house of the square screw shaft type is not manufactured and sold. The reason for this is that the manufacturing of the square screw shaft used in the lifting device for personal houses is extremely expensive, and the weight is heavy and the workability is poor. (1) The length of the square screw shaft used in the elevating device for a private house needs to be about 3 m for a two-story building and about 6 m for a three-story building. (2) The lead angle of the square screw shaft is 10 to prevent the car from falling.
It is desirable to set it to be less than or equal to °, and it is necessary to increase the screw lead and the screw diameter in order to keep the ascending / descending speed of the elevator for personal houses at a certain speed or higher while suppressing sound vibration. (In order to obtain a lifting speed of 12 meters per minute according to the "Home Elevator Design Guidelines" of the Japan Building Center, the nut that fits into the square screw shaft is 333 revolutions per minute, and the square screw shaft lead is 36 mm. When the screw lead angle is 10 ° or less, the square screw shaft diameter is 6 at the center of the screw thread.
8 mm. (3) Long and large-diameter square screw shaft (for example, the above-mentioned length 3
If the lead 36 mm and the screw thread central portion diameter 68 mm square screw shaft of m and 6 m are manufactured by cutting, the manufacturing cost becomes extremely high. (4) The long and thick square screw shaft becomes heavy and the workability is poor.
(The square screw shaft has a weight of 85 kg at 3 m and 170 kg at 6 m.) (5) Using a large-diameter square screw shaft results in excessive performance against the load of the car, which is useless in strength design, and is cost-effective. Is extremely bad. There are problems such as. For this reason, it is considered that the square screw shaft type lifting device for personal houses has not been put to practical use.

In order to popularize the lifting device for personal houses, a long, thick, light and cheap square screw shaft is required.
Such square screw shafts are not yet manufactured or sold.
Also, a long, light and cheap square screw shaft with a large screw lead is desired for a lifting device and a horizontal transfer device with a relatively light load (2 tons or less) used in transfer equipment such as factories and warehouses. There is no cheap square screw shaft suitable. In view of such conventional problems, the object of the present invention is to
An object of the present invention is to provide a screw shaft structure capable of inexpensively manufacturing a long thick and light square screw shaft or trapezoidal screw shaft for medium / light loads, and a manufacturing method thereof.

[0009]

[Means for Solving the Problems]

 [Detailed description of the invention]

[0010]

In order to achieve the above-mentioned object, the screw shaft structure of the present invention forms a metal tube (referred to as a screw shaft base material) and a square screw or a trapezoidal screw portion as the main body of the screw shaft. It is characterized in that it is composed of two members, namely, a metal member (referred to as a thread member). The thread member uses a metallic material made by drawing or extruding.

In the square screw shaft of the present invention, a thread member is wound around the outer surface of the screw shaft base material, and these two members are integrally welded and fixed by arc welding, laser beam welding or the like.

[0012]

The square screw shaft or the trapezoidal screw shaft structure according to the present invention uses a metal pipe material as the screw shaft base material and is formed by winding a metal thread member, so that the weight can be significantly reduced and the material cost is low. Become. Also, because the two members are assembled and made,
Compared with a normal square screw shaft made by cutting a thread from a bar material, equipment depreciation costs, tool costs, and labor costs are lower, and it can be manufactured at low cost.

Further, according to the present invention, a long screw shaft, which has been difficult to manufacture by the conventional technique, can be easily manufactured without using a large machine tool.

Since the constituent member of the screw shaft is divided into two parts, that is, the screw shaft base material and the screw thread member, the material, dimension and shape, heat treatment and fixing method of the member can be appropriately selected, so that the optimum structure is obtained. be able to. For example, an inexpensive and high-performance screw shaft can be produced by welding and fixing the two thread members by arc welding or laser beam welding, using alloy steel or stainless steel with high durability as the screw thread member and steel tube as the screw shaft base material.

Since the screw shaft of the present invention is composed of two members and has a structure capable of fillet welding, welding work is easy. In addition, since welding is performed between two members, heat transfer is better than welding between three members, which facilitates melting and ensures stable quality. In addition, visual inspection is easy.

[0016]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a reference view for explaining a square screw shaft used in a lifting device for a private house. In FIG. 1, reference numeral A is a square screw shaft, reference numeral B is a female screw, 20 is a drive motor, 21 is a pinion for rotating a gear on the outer circumference of the female screw, and reference numeral K is a basket of an elevating device. The length of the square screw shaft used for the lifting device for two floors needs to be about 3 m, and for the three floors it needs to be about 6 m. If the lead angle of the square screw shaft is set to 10 degrees, which is within the friction angle, the internal screw rotation is 333 revolutions per minute, and the speed of the lifting device is 12 m per minute so that the screw shaft diameter is 68 m.
m, screw lead size 36 mm. That is, the square screw shaft required for the lifting device for a private house is a long screw screw shaft having a large diameter and a large lead dimension. If square screw shafts of this size are made by conventional cutting, material costs and processing costs will be high, and it will be difficult to satisfy consumers.

FIG. 2 is a reference view showing an ordinary square screw A, which is made by cutting a rod or a pipe with a thread cutting machine. The manufacture of thick and long square screw shafts requires a large thread lathe. Further, in the case of cutting a square screw shaft having a large lead dimension, since it has to be processed at a low rotation speed due to the cutting speed, it takes a long processing time to increase the cost.

FIG. 3 is a reference view showing a screw shaft (Japanese Patent Application No. 6-142130) composed of three members. In FIG. 3, reference numeral 1 is a screw shaft base material of a metal tube, 2 is a thread material, 3 is a thread support material, and 4 is a welded portion for welding and fixing the three members.

FIG. 4 is a reference view showing a screw shaft (Japanese Patent Application No. 7-84444) composed of two members. In FIG.
Reference numeral 1 is a screw shaft base material of a metal tube, 5 is a thread member, 4 is 2
It is a welded portion for welding and fixing members.

5 to 10 are explanatory views for explaining the structure of the screw shaft of the present invention. FIG. 5: is explanatory drawing explaining the structure of a square rod one side welding assembly screw shaft. In FIG. 5, reference numeral 1 is a metal pipe (hereinafter referred to as a screw shaft base material) that serves as a main body of a square screw shaft, 5-1 is a metal having a quadrangular cross section (hereinafter referred to as a screw thread member), and 4 is a screw thread member. And a welded portion for welding and fixing the screw shaft base material. The square screw shaft has a thread member 5-1 spirally closely wound around the outer surface of the screw shaft base material 1,
It is made by welding one end of a root portion of a square thread portion formed by a thread member continuously or intermittently by arc welding. Welding both sides of the root increases the strength, but there is a problem that the weld and the internal thread interfere. If only one side is welded, the square screw surface on the upper side that receives the vertical load is flat so that it can make smooth contact with the female screw and the lower weld can support the vertical load. If this assembled type square screw shaft is used for medium-load and low-load applications, there is no fear of insufficient strength, and cost benefits can be enjoyed.

FIG. 6 is an explanatory view for explaining the structure of the rectangular rod one side welded assembly screw shaft. In FIG. 6, reference numeral 1 is a metal pipe which is a screw shaft base material, 5-2 is a metal member which is a screw thread member having a rectangular cross section, and 4 is a welded portion for welding and fixing the screw thread member and the screw shaft base material. The square screw shaft has a screw thread member (referred to as a screw thread member or a rectangular screw thread member) wound around the outer surface of the screw shaft base material 1 in a spiral shape with its long side in contact with the screw shaft base material. Is formed by continuously or intermittently welding and fixing one side of the root portion of the square screw portion formed by the method such as arc welding or laser welding. Since the screw thread member is rectangular, the deformation resistance against axial load is larger than that of the square screw thread member, and a sturdy square screw shaft can be formed.

FIG. 7 is an explanatory view for explaining the structure of the concave member assembling screw shaft. In FIG. 7, reference numerals A metal member (referred to as a thread member or a concave thread member) 4 is a welded portion for welding and fixing the thread member and the screw shaft base material. The square screw shaft has a concave thread member 5-3 in which a thread member is spirally wound around the outer surface of the screw shaft base material 1.
The concave portions are continuously or intermittently welded and fixed by arc welding or laser welding.
This square screw shaft can be used not only for lifting and lowering, but also for horizontal transportation, since there is no welded portion on the surface that the female screw contacts. FIG. 8 is an explanatory view for explaining the thread member of the concave assembly screw shaft. In FIG. 8, reference numeral 1 is a screw shaft base material, which is a metal pipe, 5-31 to 5-36 are thread members of various shapes, and 4 is a welded portion. Reference numeral 7 is a hole or slit for improving welding and welding of the two members.

FIG. 9 is an explanatory view for explaining the structure of the double-threaded rod assembly screw shaft. In FIG. 9, reference numeral 1 is a screw shaft base material, a metal pipe, 5-1 and 5-1 are thread members, and two metal square rods 4 and 4 are welded portions. Square screw shaft is the screw shaft base material 1
The two thread members 4, 4 are spirally wound on the outer surface of the coil with an appropriate gap for welding, and the roots of the two metal square bars facing each other are continuously or intermittently attached to the screw shaft base material 1. It is made by welding and fixing by arc welding or laser welding. This square screw shaft can be used not only for lifting and lowering, but also for horizontal transportation, since there is no welded portion on the surface that the female screw contacts.

FIG. 10 is an explanatory view for explaining the structure of the M-shaped thread member assembly screw shaft. In FIG. 10, reference numeral 1 is a screw shaft base material, and 5-4 is a threaded portion where two surfaces in contact with a female screw face each other. 4 is a welded part. In the square screw shaft, the M-shaped thread member 5-4 is spirally wound around the outer surface of the screw shaft base material 1 with a clearance C suitable for welding, and the clearance between the M-shaped thread members 5-4 is continuous. It is produced by welding or fixing the thread base material 1 by arc welding intermittently or intermittently. The clearance C can be made zero if the thread member shape and welding conditions are such that welding melt-in can be guaranteed. This square screw shaft can be used not only for lifting and lowering, but also for horizontal transportation, since there is no welded portion on the surface that the female screw contacts.

FIG. 11 is an explanatory view for explaining a method of manufacturing the assembled screw shaft. In FIG. 11, reference numeral 12 is a screw member feeding device (decoiler), and 13 is a screw member guide roll that feeds the screw member 5 to the bending rollers 41 to 44. Reference numeral 10 denotes a screw shaft base material feeding device, which uses the master screw shaft 17 fixed on the bed 15 as a guide.
The drive motor 20 mounted on the No. 8 rotates the sleeve 23 via a gear (not shown in the figure) in the carrier 18. The screw shaft base material 1 is fixed to the sleeve 23 by a stopper 19, and is given rotation and axial feed by the screw shaft base material feeding device 10. The screw shaft base material 15 includes bending rollers 41 to 44.
And the end portion is fixed to the screw shaft base material 1, and the screw shaft base material 1 is given rotation and axial feed by the screw shaft base material feeding device 10. The material 1 is tightly wound around the outer surface of the material 1. The wound thread member 5 is welded and fixed to the screw shaft base material 1 by the welding machines 55 and 56 to form an assembled screw shaft.

FIG. 12 is an explanatory view for explaining the structure of the bending roller. In FIG. 12, reference numeral 40 is a bending roller housing, and reference numerals 41, 42 and 43 are bending rolls, which bend the thread member 5 into a circle. Reference numeral 44 denotes a presser roll, which presses the screw thread member 5-3 together with the roll 42 and rotationally drives the 44-1 and 44-2 parts to rotate the screw thread member 5.
-3 is supplied to the screw shaft base material 1. The roll 43 is a roll required when setting the screw thread member 5-3 on the screw shaft base material 1, and after the screw thread member 5 is welded and fixed to the screw shaft base material 1 as shown by the arrow A, the screw thread is formed. It may be separated from the member 5-3. Reference numeral 50 is a gauge, and 51 is a positioning tool for the screw shaft base material 1. In order to wind the thread member in close contact with the screw shaft base material 1 without sagging, the axis of the roll 42 is perpendicular to the axis of the screw shaft base material 1 (direction of arrow A) in the horizontal direction (B1). It is necessary to incline by θ2 degrees in the arrow direction). These angles are determined by the specifications of the screw shaft to be manufactured (the outer diameter dimension of the base material and the width of the thread member).

FIG. 13 is an explanatory view for explaining the structure of the screw shaft manufacturing apparatus. In FIG. 13, reference numeral 15 is a bed of a screw shaft manufacturing apparatus, on which a master screw shaft 17 is fixedly supported at both ends by a stand 16. Reference numeral 18 denotes a carrier, and the screw shaft base material 1 is fixed to a sleeve 23, which is a component of the carrier, by a holder 19, and a motor 20 causes a sleeve 23 to engage a master screw shaft 17 with a female screw 29 fitted to the sleeve 23 via a gear. Since the screw shaft base material 1 is rotated, rotation and feed are simultaneously applied. Reference numeral 39 is a tool base on which a bending roller housing 40, a roll 41,
42, 43, 44 are listed. The screw shaft base material 1 is arranged above the bending roller. Reference numeral 5 denotes a material wound around the screw shaft base material, that is, a thread member. Code 5
Reference numeral 0 is a gauge for preventing the variation of the screw leads of the assembled screw shaft, and the thread member 5 is the bending rollers 41 to 4
The size is regulated by this gauge when it is molded in 4 and wound around the screw shaft base material. This gauge also has the function of ironing square screw shapes. Reference numeral 55 denotes a welding torch of a welding machine, which fixes the thread member 5 to the screw shaft base material 1 by welding in a process after the wound thread member 5 is dimensionally regulated by the gauge 50. As the welding machine, an arc welding machine, a laser beam welding machine, or the like is used. Reference numerals 52 and 53 are stands that support the screw shaft.

FIG. 14 is an explanatory view for explaining the structure of a carrier whose feed pitch can be changed. Reference numeral 18 in FIG.
Is a carrier housing that slides on the bed 15 2
Reference numeral 0 is a drive motor, and 21 is a gear (pinion) fixed to the motor shaft. The pinion is a gear 2 that connects a sleeve 23 that fixes the screw shaft base material 1 to the center portion.
Rotate 2. The gear 22 has a key (26) on a shaft 25 whose central axis can move at an equal distance from the rotation center of the gear 22.
The gear 24 fixed by is rotated. Shaft 25
Next to the gear 24 is the gear 27 (27-1 or 27-
2) is also fixed with a key and makes the same rotation.
The gear 27 (27-1 or 27-2) rotates the gear 28 that connects the female screw 29 fitted in the master screw shaft 17 at the center portion. As a result, the sleeve 23
Since the female screw 29 rotates, the carrier is fed along the master screw shaft with the slide 33 guided by the slideways 34 and 35 above the bed 15. Therefore, the screw shaft base material 1 fixed to the sleeve is simultaneously supplied with rotation and feed. In order to feed the screw shaft base material 1 by increasing or decreasing the feed pitch of the master screw shaft 17, the number of teeth of the gear 27 may be changed and the shaft 25 may be rotationally slid and fixed at the position where the gears mesh with each other. The gear 27-1 shows an example of pitch expansion and the gear 27-2 shows an example of pitch reduction. Gear 27 is gear 24
When the number of teeth is the same as that of the master screw shaft, the feed pitch can be obtained. For example, the number of teeth of the gears 22 and 28 is 112, the number of teeth of the gear 24 is 56, and the feed pitch of the master screw is 28 m.
m, the number of teeth of the gear 27 is 72, 64, 56, 4
When changed to 8, 40, the feed pitch of the screw shaft base material becomes 36, 32, 28, 24, 20 mm, respectively.

FIG. 15 is an explanatory view for explaining the internal structure of the carrier. In FIG. 15, reference numerals 18-1 and 18-2
Is a carrier housing, sleeve 23, shaft 25,
A female screw 29 is contained via a bearing 30. The carrier housing 18-1 mounts the drive motor 20, and the carrier housing 18-2 has an opening lid 31 for replacing the gear 27. 32 is a shaft 25
Is a cover with a positioning pin 36 for fixing the to the housing. Reference numeral 21 is a pinion, 22 is a sleeve 23
Gears that are fastened with, 23 is a sleeve for screw shaft rotation,
24 is an intermediate gear, 25 is a shaft, 26 is a key,
Reference numeral 27 is a gear for changing the feed pitch, and 28 is a gear fastened to a female screw. Reference numeral 1 is a screw shaft base material, 19, 19-
Reference numeral 1 is a fixture for fixing the screw shaft base material 1 to the sleeve 23. Reference numeral 33 is a slide of the carrier housing.

[0034]

As is apparent from the above description, according to the screw shaft structure and the screw shaft manufacturing method of the present invention, the screw shaft is light and has a long angle for assembling the screw shaft base material 1 and the thread member 5. Screws or trapezoidal screw shafts can be made very inexpensively. For example, when a 3 m long square screw shaft (part in FIG. 1A) used in a melting and elevating device for a two-story private house is compared with the machined square screw shaft and the assembled screw shaft of the present invention, the assembled square screw shaft shows the weight of the product. It is about one-third, and the price is about one-tenth, which is a great effect. INDUSTRIAL APPLICABILITY The screw shaft of the present invention does not have to machine a thread from a bar material, can produce a screw shaft in a short time without producing chips, and can reduce material costs and processing costs. It can be manufactured at lower cost than In addition, it is possible to easily manufacture long rectangular screw shafts and trapezoidal screw shafts that are difficult to manufacture due to the size restrictions of equipment in machining. Further, since the screw shaft has a divided structure, it is possible to optimally select the material, size, shape, heat treatment and fixing method according to the characteristics required for the screw, and it is possible to design efficiently structurally. As a result, it becomes possible to manufacture at low cost and in a short period of time. INDUSTRIAL APPLICABILITY The screw shaft of the present invention is most suitable for the field of long screw shafts that are used with medium and light loads, and is used for elevating devices for personal houses, stair elevating devices, vertical or horizontal conveying devices used in factories and warehouses, etc. It can be widely used and its economic effect is great. By manufacturing the square screw shaft of the present invention, it is possible to develop, produce and sell a safe and inexpensive screw-type lifting device for a personal house, which can greatly contribute to the welfare and welfare of an aging society.

[Brief description of the drawings]

FIG. 1 is a reference diagram illustrating a square screw shaft used in a lifting device for a private house.

FIG. 2 is a reference diagram showing a normal square screw shape.

FIG. 3 is a screw shaft composed of three members (Japanese Patent Application No. 6-142).
Fig. 130)

FIG. 4 is a screw shaft composed of two members (Japanese Patent Application No. 7-844).
44) Reference drawing

FIG. 5 is an explanatory view for explaining the structure of a square rod one side welded assembly screw shaft.

FIG. 6 is an explanatory view for explaining the structure of a rectangular rod one side welded assembly screw shaft.

FIG. 7 is an explanatory view for explaining the structure of the concave member assembling screw shaft.

FIG. 8 is an explanatory view for explaining a thread member of the concave member assembly screw shaft.

FIG. 9 is an explanatory diagram illustrating the structure of a double-screw rod assembly screw shaft.

FIG. 10 is an explanatory view for explaining the structure of the M-shaped thread member assembly screw shaft.

FIG. 11 is a bird's-eye view illustrating a method of manufacturing the assembled screw shaft.

FIG. 12 is an explanatory diagram illustrating a structure of a bending roller.

FIG. 13 is an explanatory diagram illustrating a structure of a screw shaft manufacturing apparatus.

FIG. 14 is an explanatory diagram illustrating the structure of a carrier whose feed pitch can be changed.

FIG. 15 is an explanatory diagram illustrating the internal structure of the carrier.

[Explanation of symbols]

A Normal square screw B Female screw C Gap (clearance) K Elevator cage (cage) 1 Screw shaft base material 2 Screw thread material 3 Screw thread support material 4 Welded part 5, 5-1, 5-2, 5-3 5-4, 5-11, 5-
12, 5-31 to 5-3 6 screw thread member 7 hole or slit of screw thread member 10 screw shaft base material feeding device (assembly screw shaft manufacturing device) 12 screw member feeding device (decoiler) 13 screw member Guide roll 15 Bed 16 Stand 17 Master screw shaft (parent screw shaft) 18, 18-1, 18-2 Carrier, carrier housing 19, 19-1 Stopper 20 Drive motor 21 Gear (pinion) 22, 24, 27, 27 -1, 27-2, 28 Gear 23 Sleeve 25 Shaft 26 Key 29 Female thread 30 Bush (bearing) 31 Removal window 32 Lid 33 Slide 34, 35 Slideway 36 Positioning pin 39 Tool rest 40 Housing 41, 42, 43 Roller 42- 1, 44-1 Roller drive shaft 44 Presser roller 50 Gauge 51st Determining tool 52, 53 stand 55 welding torch (welding machine) 56 welder

Continued on the front page (72) Inventor Masao Okubo 3-9-20 Teraonaka, Ayase City, Kanagawa Prefecture (72) Inventor Kazuko Okubo 3-9-20, Teraonaka, Ayase City, Kanagawa Prefecture (72) Inventor Shin Okubo Ayase, Kanagawa Prefecture (9) Inventor Gen Okubo 3-9-20 Teraonaka, Ayase City, Kanagawa Prefecture

Claims (6)

[Claims] 1. The outer diameter of the body of the square screw shaft is 30 mm.
To 120 mm metal pipe (referred to as a thread base material), a square-shaped metal member (referred to as a thread member) having a square section is spirally wound on the outer surface of the metal thread (referred to as a thread base material), and a square screw formed by the thread member is formed. An assembled square screw shaft, characterized in that one side of the root of the part is welded and fixed to the thread base material by arc welding. 2. The outer diameter of the body of the square screw shaft is 30 mm.
To 120 mm metal pipe (called thread base material) has a rectangular cross section forming a square threaded portion on the outer surface, and the quotient of long side divided by short side is 1.25 to 2.50. A thread member (called a thread member or rectangular thread member) is spirally wound so that the long side is in contact with the screw shaft base material, and one side of the root of the square thread portion formed by the thread member is arc welded. An assembled type square screw shaft characterized by being welded and fixed to the thread base material by. 3. A square screw portion is formed on the outer surface of a metal pipe (referred to as a screw shaft base material) which is a main body portion of the square screw shaft. Shaped screw thread member) is wound in a spiral shape, and the concave portion of the recessed screw thread member is welded and fixed to the thread base material by arc welding. 4. Two metal square bars (called screw thread members) forming a square screw section are formed on an outer surface of a metal pipe (called a screw shaft base material) which is a main body section of the square screw shaft. An assembled type square screw shaft, which is wound in a spiral shape, and the gap between two screw thread members is welded and fixed to a screw shaft base material by arc welding. 5. A metal pipe (referred to as a screw shaft base material) serving as a main body portion of the square screw shaft has two surfaces facing the female screw of the square screw shaft, which face each other inside the thread member. Metal variant Is a spiral screw-shaped winding with a slight gap between the screw thread members, and the gap portion between the screw thread members is welded and fixed to the screw thread base material by arc welding. 6. A thread member supplying device for supplying the thread member according to the above-mentioned claim, and a thread member bending roll for manufacturing the assembled type square screw shaft of claims 1, 2, 3, 4, and 5. A screw shaft base material feeding device that applies predetermined rotation and feed to the screw shaft base material by guiding the master screw shaft and winds the thread member bent by the thread member bending roll around the outer surface of the screw shaft base material. A method for manufacturing an assembled type screw shaft, comprising a welding machine for welding and fixing a thread member wound around a screw shaft base material to the screw shaft base material.