WO2024058035A1 - Welding method for first cylindrical part and second cylindrical part, manufacturing method for water heater, manufacturing method for compressor, and welding device - Google Patents

Abstract

This welding method for a first cylindrical part and a second cylindrical part comprises a step for forming a molten pool, and a step for rotating at least one among the first cylindrical part and the second cylindrical part. In the step for forming the molten pool, a first cylindrical end of the first cylindrical part of a first member is welded to a second cylindrical end of the second cylindrical part which is included in a second member and fitted to the first cylindrical part, the end face of the second cylindrical end being aligned with the first cylindrical end, and a molten pool straddling the first cylindrical end and the second cylindrical end is formed across the entire circumference. In the step for rotating at least one among the first cylindrical part and the second cylindrical part, said at least one among the first cylindrical part and the second cylindrical part is rotated in the circumferential direction at least in the period from the formation of the molten pool to the solidification of the molten pool.

Description

Method of welding the first cylindrical part and the second cylindrical part, method of manufacturing a water heater, method of manufacturing a compressor, and welding device

The present disclosure relates to a method of welding a first cylindrical portion and a second cylindrical portion, a method of manufacturing a water heater, a method of manufacturing a compressor, and a welding device.

A method of welding cylindrical parts together, that is, a method of welding a first cylindrical part and a second cylindrical part, involves fitting the second cylindrical part of the other member into the first cylindrical part of one member, and There is a method that includes a step of melting both cylindrical ends and welding the cylindrical ends together with the end surfaces of the cylindrical end of the second cylindrical part and the second cylindrical part aligned.

In such a welding method, the two cylindrical ends whose end surfaces are aligned have an annular shape as a whole when viewed from the axial direction of the cylinder. Therefore, the cylindrical end is melted by operating a welding device in an annular manner along the cylindrical end. For example, when laser welding is employed, the cylindrical end is melted by scanning a laser beam along the ring of the cylindrical end. However, in such a welding method, it takes time to scan the laser beam. Therefore, it takes time to melt most of the end face area of the cylindrical end. Therefore, in order to shorten the time required for melting, a processing device that simultaneously melts the entire annular region has been developed.

For example, Patent Document 1 describes a laser oscillator that outputs a laser beam, a first lens that converts the laser beam outputted by the laser oscillator into a parallel beam of a constant diameter, and a parallel beam of a constant diameter that is converted by the first lens. A laser processing device is disclosed that includes a second lens that converts parallel light into annular parallel light. In the laser processing apparatus described in Patent Document 1, since the laser beam is circular parallel light, by irradiating the above-mentioned circular cylinder end with the laser beam, the entire circular region can be melted at the same time. can.

JP2005-28428A

However, even if the entire end face area of the cylindrical end is simultaneously melted using the laser processing apparatus described in Patent Document 1, after melting, the molten material, such as molten metal, may concentrate in a certain area due to convection. There is. In that case, there will be a shortage of molten metal in areas other than some areas. As a result, the welding strength decreases and sufficient strength cannot be obtained.

The present disclosure has been made to solve the above-mentioned problems, and includes a method for welding a first cylindrical portion and a second cylindrical portion in which reduction in welding strength is suppressed, a method for manufacturing a water heater, a method for manufacturing a compressor, and a welding method for a first cylindrical portion and a second cylindrical portion. The purpose is to provide equipment.

In order to achieve the above object, a method of welding a first cylindrical part and a second cylindrical part according to the present disclosure includes a first cylindrical end of a first cylindrical part provided in a first member, a first cylindrical end provided in a second member, and a second cylindrical part provided in a second member. The first cylindrical end and the second cylindrical end of the second cylindrical part fitted into the cylindrical part, whose end surfaces are aligned, are melted to create a molten pool spanning the first cylindrical end and the second cylindrical end all around the circumference. and a step of rotating at least one of the first cylindrical portion and the second cylindrical portion in the circumferential direction at least between the formation of the molten pool and the time of solidification.

According to the configuration of the present disclosure, at least one of the first cylindrical part and the second cylindrical part is rotated in the circumferential direction at least between the formation of the molten pool and the time of solidification, so that the molten material in the molten pool is centrifuged. Convection occurs in the circumferential direction due to force. This prevents the molten material from concentrating in some areas and reducing the amount of molten material in other areas. As a result, a decrease in welding strength is suppressed.

A perspective view of a portion of a hot water storage tank including a cylindrical part to be welded in a method for welding a cylindrical part according to Embodiment 1 of the present disclosure. A perspective view of a nipple provided with another cylindrical part to be welded in the cylindrical part welding method according to Embodiment 1 of the present disclosure A cross-sectional view of a welded part when cylindrical parts are welded by the cylindrical part welding method according to Embodiment 1 of the present disclosure. A cross-sectional view of a molten pool when a cylindrical part is welded without using the cylindrical part welding method according to Embodiment 1 of the present disclosure A cross-sectional view of the molten pool and the cylindrical part when the cylindrical ends of the cylindrical parts are welded together without using the cylindrical part welding method according to Embodiment 1, when the amount of melting at the cylindrical ends is small. A cross-sectional view of the molten pool and the cylindrical part when the cylindrical ends of the cylindrical parts are welded together without using the cylindrical part welding method according to Embodiment 1, when the amount of melting at the cylindrical ends is large. A cross-sectional view of the molten pool and the cylindrical portion when the cylindrical ends of a thick cylindrical portion are welded together without using the cylindrical portion welding method according to Embodiment 1, and the amount of melting at the cylindrical end is small. A cross-sectional view of the molten pool and the cylindrical portion when the cylindrical ends of a thick cylindrical portion are welded to each other without using the cylindrical portion welding method according to the first embodiment, and the amount of melting at the cylindrical end is large. Flowchart of a method for welding a cylindrical part according to Embodiment 1 of the present disclosure A cross-sectional view of a welding device for carrying out a cylindrical part welding method according to Embodiment 1 of the present disclosure A perspective view of a cylindrical part rotated in a rotation process included in a cylindrical part welding method according to Embodiment 1 of the present disclosure and another cylindrical part into which the cylindrical part is fitted. An enlarged top view of a cylindrical part that is rotated in the rotation step of the cylindrical part welding method according to Embodiment 1 of the present disclosure and another cylindrical part into which the cylindrical part is fitted. A perspective view of two cylindrical parts rotated in a rotation process included in a cylindrical part welding method according to Embodiment 2 of the present disclosure. An enlarged top view of a cylindrical part rotated in a rotation process included in a cylindrical part welding method according to Embodiment 2 of the present disclosure Flowchart of a method for welding a cylindrical part according to Embodiment 2 of the present disclosure A top view of a cylindrical part irradiated with laser light by a laser irradiator in a melting process included in a cylindrical part welding method according to Embodiment 2 of the present disclosure. A perspective view of two cylindrical parts rotated in a modification of the rotation process included in the cylindrical part welding method according to Embodiment 2 of the present disclosure. A sectional view of a welding device used in a method for welding a cylindrical part according to Embodiment 3 of the present disclosure A sectional view of a hot water storage tank including a cylindrical part welded by a cylindrical part welding method according to Embodiment 4 of the present disclosure Flowchart of a method for welding a cylindrical part according to Embodiment 5 of the present disclosure A sectional view of a cylindrical part to which a ring member is attached in a ring member attaching step included in a cylindrical part welding method according to Embodiment 5 of the present disclosure. A cross-sectional view of a cylindrical part in which a molten pool is formed in a welding process included in a cylindrical part welding method according to Embodiment 5 of the present disclosure. A modification of the annular member used in the method for welding a cylindrical portion according to Embodiment 5 of the present disclosure and a cross-sectional view of the cylindrical portion Another modification of the annular member used in the cylindrical part welding method according to Embodiment 5 of the present disclosure and a sectional view of the cylindrical part

Hereinafter, a method for welding a first cylindrical portion and a second cylindrical portion, a method for manufacturing a water heater, a method for manufacturing a compressor, and a welding device according to an embodiment of the present disclosure will be described in detail with reference to the drawings. In addition, in the figures, the same or equivalent parts are given the same reference numerals. In the orthogonal coordinate system XYZ shown in the figure, when the tube axes of the first cylindrical part and the second cylindrical part are oriented in the vertical direction, the vertical direction is the Z axis, and the horizontal plane is the XY plane. Hereinafter, this coordinate system will be cited and explained as appropriate.

(Embodiment 1)
The method of welding the first cylindrical part and the second cylindrical part according to the first embodiment is a method of welding the first cylindrical part surrounding a through hole formed by burring and the second cylindrical part forming a circular tube. It is. Hereinafter, we will use as an example a case where a first cylindrical part formed by burring at the water supply port of a hot water storage tank provided in a water heater and a second cylindrical part provided at the tip of the nipple and forming a circular pipe are welded. A method of welding the first cylindrical part and the second cylindrical part according to the first embodiment will be described. First, with reference to FIGS. 1 to 3, each of the first cylindrical part and the second cylindrical part and the welded part when the first cylindrical part and the second cylindrical part are combined and welded will be described.

Note that hereinafter, the first cylindrical part and the second cylindrical part will be simply referred to as cylindrical parts.

FIG. 1 is a perspective view of a portion of a hot water storage tank 10 including a cylindrical portion 1 to be welded in a method for welding cylindrical portions 1 and 2 according to the first embodiment. FIG. 2 is a perspective view of a nipple 20 that includes another cylindrical portion 2 to be welded in the same welding method. FIG. 3 is a cross-sectional view of the welded portion 5 when the cylindrical portion 1 and the cylindrical portion 2 are welded using the same welding method. Note that, for ease of understanding, FIG. 1 shows only a portion of the hot water storage tank near the water supply port. Moreover, FIG. 3 shows a cross section when the cylindrical parts 1 and 2 are cut along a plane along the cylindrical axis.

As shown in FIG. 1, the hot water tank 10 installed in the water heater has a through hole 12 in the wall portion 11 to supply water to the hot water tank 10. This forms a water supply port. The through hole 12 is surrounded by a cylindrical portion 1 formed by burring to connect a pipe. A nipple 20 is inserted into this cylindrical portion 1 to facilitate connecting the pipe.

On the other hand, the nipple 20 has a tube shape with a tapered tip, as shown in FIG. In detail, the nipple 20 has a cylindrical main body part 21 for inserting and connecting a pipe from an external device, and a cylindrical part 1 of the hot water storage tank 10 mentioned above to be connected, so that the nipple 20 is larger than the main body part 21. It has a cylindrical part 2 which is provided on the tip side, that is, on the +Z side, and has a smaller outer diameter and inner diameter than the main body part 21.

The cylindrical part 2 can be fitted into the cylindrical part 1 of the hot water storage tank 10, and has an outer diameter that allows it to come into close contact with the inner wall of the cylindrical part 1 when fitted into the cylindrical part 1. The cylindrical part 2 is fitted concentrically with the cylindrical part 1 and joined to the cylindrical part 1, as shown in FIG.

In detail, the cylindrical part 2 is inserted into the internal space of the cylindrical part 1 and is concentric, and the cylindrical end 23 thereof is oriented in the same direction as the cylindrical end 13 of the cylindrical part 1, and the end surfaces are aligned with each other. state and is positioned. That is, the cylindrical portion 2 is positioned in the cylindrical portion 1 with the cylindrical ends 13 and 23 facing in the +Z direction and with the Z positions of the +Z end faces aligned. A welded portion 5 is provided at the cylindrical end 23 of the cylindrical portion 2 and the cylindrical end 13 of the cylindrical portion 1. Thereby, the cylindrical end 23 of the cylindrical portion 2 and the cylindrical end 13 of the cylindrical portion 1 are joined to each other.

The welded portion 5 is formed by once melting and solidifying the materials forming the cylindrical end 13 of the cylindrical portion 1 and the cylindrical end 23 of the cylindrical portion 2. Specifically, the cylindrical parts 1 and 2 are made of a metal material, specifically, a steel material such as ferritic stainless steel or martensitic stainless steel. The welded portion 5 is formed by once melting the metal material forming the cylindrical ends 13 and 23 and then solidifying it.

In forming this welded portion 5, the molten metal material may gather in one part, and as a result, sufficient welding strength may not be obtained. Therefore, in order to solve this problem, in the step of forming the welded portion 5, the method of welding the cylindrical portions 1 and 2 according to the first embodiment is performed. Next, the problem of welding strength will be explained with reference to FIGS. 4, 5A, 5B, 6A, and 6B.

FIG. 4 is a cross-sectional view of the molten pool 60 when the cylindrical parts 1 and 2 are welded without using the cylindrical part welding method according to the first embodiment. FIG. 5A shows melting when the amount of melting of the cylindrical ends 13 and 23 is small when the cylindrical ends 13 and 23 of the cylindrical parts 1 and 2 are welded together without using the welding method of the cylindrical parts according to the first embodiment. FIG. 6 is a sectional view of a pond 60 and cylindrical parts 1 and 2. FIG. 5B shows the molten pool 60 and the cylindrical parts 1, 2 when the cylindrical ends 13, 23 of the cylindrical parts 1, 2 are welded together without using the same welding method, when the molten amount of the cylindrical ends 13, 23 is large. FIG. In FIG. 4, for ease of understanding, only typical flows of molten metal are shown by arrows A1-A4. Furthermore, in FIGS. 5A and 5B, the shapes of the cylindrical portions 1 and 2 are simplified.

As described above, the welding part 5 joins the cylindrical end 13 of the cylindrical part 1 and the cylindrical end 23 of the cylindrical part 2. At this time, in order to ensure sufficient joint strength and watertightness, the cylindrical ends 13 and 23 need to be joined over the entire circumference. Therefore, although not shown in FIG. 3, the welded portion 5 is not only provided across the cylindrical ends 13 and 23, but is also formed along the circumferences of the cylindrical ends 13 and 23. As a result, the welded portion 5 is provided over the entire circumference of the cylindrical ends 13, 23. Thereby, the welded portion 5 has an annular shape when viewed from above, that is, when viewed from the +Z side.

In order to form the welded portion 5 having such a shape, it is conceivable to move the heating mechanism that melts the cylindrical ends 13 and 23 in the circumferential direction to gradually form the molten pool 60 in the circumferential direction. However, in this case, it takes time to form the welded portion 5. Furthermore, a moving mechanism is required to move the heating mechanism in the circumferential direction. Equipment tends to become complicated.

Therefore, in order to shorten the welding time or simplify the device configuration, it is desirable to simultaneously melt the entire circumferential direction of the cylindrical ends 13 and 23 using a laser irradiation device that can irradiate laser light in an annular shape. .

However, when using such a laser irradiation device, if the entire circumferential direction of the cylindrical ends 13, 23 is simply melted at the same time, as shown in FIG. The molten metal is concentrated in one part, and a pool 61 is generated in which more molten metal has accumulated than in the surrounding area. This is because, from experimental results, (1) the entire circumferential direction of the cylindrical ends 13, 23 was simultaneously melted to form a molten pool 60 containing a relatively large amount of molten metal that spread over the entire cylindrical ends 13, 23; (2) The area of the molten pool 60 is large, in other words, the molten pool 60 is long in the circumferential direction, and as a result, Marangoni convection occurs in the circumferential direction of the cylindrical ends 13 and 23, and molten metal This is thought to be due to the concentration of

To explain in more detail, as shown in FIG. 5A, if the end surfaces of the cylindrical ends 13 and 23 are only slightly melted, interfacial tension at the end surfaces of the cylindrical ends 13 and 23 acts on the molten metal, and the interface The tension makes it difficult for the molten metal to flow within the molten pool 60. As a result, the accumulation portion 61 described above does not occur. However, in this case, sufficient welding strength cannot be obtained because the amount of molten metal is small.

On the other hand, in order to obtain sufficient welding strength, if the end face portions of the cylindrical ends 13 and 23 are sufficiently melted as shown in FIG. It only works on the molten metal on the side, that is, on the -Z side in the molten pool 60. As a result, the molten metal on the +Z side within the molten pool 60 flows due to Marangoni convection. At this time, as shown by arrows A1-A4 in FIG. 4, the molten metal on the +Z side flows toward a lower temperature region. As a result, the above-described pooled portion 61 is generated. When such a pooling portion 61 occurs, the amount of molten metal decreases in areas other than the location where the pooling portion 61 exists, and as a result, the welding strength decreases.

Furthermore, this problem occurs not only in the cylindrical parts 1 and 2 with a small thickness, but also in the cylindrical parts 1 and 2 with a large thickness.

FIG. 6A shows that when the cylindrical ends 13 and 23 of the thick cylindrical parts 1 and 2 are welded together without using the cylindrical part welding method according to the first embodiment, the amount of melting at the cylindrical ends 13 and 23 is small. FIG. 4 is a cross-sectional view of the molten pool 60 and the cylindrical parts 1 and 2 at that time. FIG. 6B shows the molten pool 60 and the cylindrical portion when the cylindrical ends 13 and 23 of the thick cylindrical portions 1 and 2 are welded to each other without using the same welding method, and when the molten amount of the cylindrical ends 13 and 23 is large. 1 and 2 are cross-sectional views. Note that in FIGS. 6A and 6B, the shapes of the cylindrical portions 1 and 2 are simplified for easy understanding.

As shown in FIG. 6A, when the thickness of the cylindrical parts 1 and 2 is large, if only a part near the boundary between the cylindrical parts 1 and 2 in the thickness direction is melted, the surface of the cylindrical ends 13 and 23 and the molten metal are melted. Interfacial tension acts between them, making it difficult for the molten metal to flow within the molten pool 60. As a result, the accumulation portion 61 described above does not occur. However, since the amount of molten metal is small, sufficient welding strength cannot be obtained as in the case of FIG. 5A.

On the other hand, as shown in FIG. 6B, when the end face portions of the cylindrical ends 13 and 23 are sufficiently melted, as in the case of the thin cylindrical portions 1 and 2 in FIG. 5B, the inside of the molten pool 60 The molten metal on the +Z side flows due to Marangoni convection, and the above-mentioned pool 61 is generated. As a result, the amount of molten metal decreases in areas other than where the pool 61 is located, resulting in a decrease in welding strength.

In this way, irrespective of the thickness of the cylindrical parts 1 and 2, if the molten pool 60 is formed that sufficiently covers the end surface area of the cylindrical ends 13 and 23, the pooled part 61 shown in FIG. will decrease. In order to suppress the occurrence of this pooled portion 61, the method of welding the cylindrical portions 1 and 2 according to the first embodiment is performed.

Next, a method for welding the cylindrical parts 1 and 2 according to the first embodiment will be described with reference to FIGS. 7 to 10. Note that this welding method uses a dedicated welding device. In the following description, in addition to the method of welding the cylindrical parts 1 and 2 according to the first embodiment, the configuration of the welding apparatus will also be described.

FIG. 7 is a flowchart of a method for welding the cylindrical parts 1 and 2 according to the first embodiment.

As shown in FIG. 7, the welding method for cylindrical parts 1 and 2 includes a melting process (step S1) of melting the welded parts of cylindrical parts 1 and 2, and a cylindrical axis of one of cylindrical parts 1 and 2 during melting. and a rotation step (step S2) of rotating around the .

In the method of welding the cylindrical parts 1 and 2, first, as a premise of welding, a hot water storage tank 10 having the above-mentioned cylindrical part 1 and a nipple 20 having the above-mentioned cylindrical part 2 are prepared, and the nipple 20 is attached to the hot water storage tank 10. Assemble. Specifically, the cylindrical part 2 is fitted into the cylindrical part 1 from the end 14 of the cylindrical part 1 shown in FIG. 3 on the wall part 11 side of the hot water storage tank 10, with the cylindrical end 23 first. Further, the positions of the end surfaces of the cylindrical end 13 of the cylindrical portion 1 on the side opposite to the wall surface portion 11 and the cylindrical end 23 on the tip side of the cylindrical portion 2 are aligned. For example, the end faces of the cylindrical end 13 of the cylindrical part 1 and the cylindrical end 23 of the cylindrical part 2 are made perpendicular to the Z axis, and the Z positions of these end faces are aligned. Thereby, the cylindrical part 2 is fitted into the cylindrical part 1. As a result, the nipple 20 is assembled to the hot water storage tank 10.

Returning to FIG. 7, a melting process is next performed (step S1). In this welding process, in order to weld the end faces of the cylindrical end 13 of the cylindrical part 1 and the cylindrical end 23 of the cylindrical part 2, the end faces of the cylindrical ends 13 and 23 are melted using the welding device 4A.

Here, the configuration of the welding device 4A used in the melting process will be explained with reference to FIG. 8.
FIG. 8 is a sectional view of a welding device 4A for carrying out the method of welding the cylindrical parts 1 and 2 according to the first embodiment. Note that in FIG. 8, the internal structures of the laser irradiator 43 and the motor 44 are omitted for easy understanding. Furthermore, the shapes of the cylindrical parts 1 and 2 are simplified.

As shown in FIG. 8, the welding device 4A includes a holding mechanism 41 that holds the cylindrical part 1 that is the welding target, a holding mechanism 42 that holds the cylindrical part 2 that is the other welding target, and the holding mechanism 41. It includes a laser irradiator 43 that melts and welds the held cylindrical part 1 and the cylindrical part 2 held by the holding mechanism 42.

The holding mechanism 41 has a large cylindrical part 411 that holds the cylindrical part 1 and a flange part 412 that fixes the large cylindrical part 411.

The large cylindrical portion 411 is a portion that supports the wall portion 11 of the hot water storage tank 10 at its own cylindrical end. The large cylindrical portion 411 has a cylindrical end 413 having an end face perpendicular to the cylindrical axis A, and by orienting the cylindrical axis A in the vertical direction, the end face of the cylindrical end 413 is made horizontal. Thereby, the large cylindrical portion 411 allows the wall portion 11 of the hot water storage tank 10 to be placed on the cylindrical end 413.

Although not shown, the end surface of the cylindrical end 413 is in the shape of a ring. As shown in FIG. 8, an annular magnet 414 having the same shape as the end surface is provided on the end surface of the cylindrical end 413. As shown in FIG. The cylindrical end 413 holds the wall portion 11 of the hot water storage tank 10 by the magnetic force of the magnet 414 when the wall portion 11 of the hot water storage tank 10 is placed thereon. On the other hand, a flange portion 412 is provided at a cylindrical end portion of the large cylindrical portion 411 opposite to the cylindrical end 413 .

Although not shown, the flange portion 412 has a circular ring shape with a horizontal circular ring surface. The flange portion 412 is arranged coaxially with the large cylindrical portion 411. Further, the flange portion 412 has an annular inner diameter smaller than the inner diameter of the large cylindrical portion 411, and as a result, protrudes toward the inner space of the large cylindrical portion 411. As shown in FIG. 8, a bearing portion 441 provided on the motor 44 is passed through the inner space of the large cylindrical portion 411. As shown in FIG. The bearing portion 441 is fitted into the annular flange portion 412. The bearing portion 441 is integrally formed with a case 442 of the motor 44. As a result, the flange portion 412 is fixed to the case 442 of the motor 44.

On the other hand, the flange portion 412 is formed integrally with the large cylindrical portion 411. The flange portion 412 is fixed to the case 442 of the motor 44 to maintain the large cylindrical portion 411 at a constant position. As a result, when the large cylindrical portion 411 holds the wall portion 11 of the hot water storage tank 10 by the magnetic force of the magnet 414, the flange portion 412 maintains the wall portion 11 of the hot water storage tank 10 at a constant position.

On the other hand, the holding mechanism 42 has a cylindrical part 421 that is inserted into the cylindrical part 2 and a flange part 422 that supports the cylindrical part 421.

The cylindrical part 421 has an outer diameter smaller than the inner diameter of the cylindrical part 2 to the extent that a minute gap is formed between the cylindrical part 421 and the cylindrical part 2, and can be fitted into the cylindrical part 2 when the cylindrical part 2 is covered. be. The cylindrical portion 421 is arranged with the cylindrical axis B facing the vertical direction. A flange portion 422 is provided at the lower end of the cylindrical portion 421 in order to support the cylindrical portion 2 when the cylindrical portion 2 is fitted over the cylindrical portion 2 .

The flange portion 422 protrudes from the cylindrical portion 421 to be larger than the thickness of the cylindrical portion 2. Thereby, the collar portion 422 prevents the cylindrical portion 2 from slipping downward when the cylindrical portion 2 is fitted over the cylindrical portion 421. Furthermore, an annular magnet 423 is provided above the collar portion 422 . This magnet 423 attracts the cylindrical portion 2 due to its magnetic force when the cylindrical portion 2 is fitted over the cylindrical portion 421 .

The holding mechanism 42 holds the cylindrical portion 2 with such a configuration. A laser irradiator 43 is arranged above the holding mechanisms 41 and 42 in order to weld the cylindrical parts 1 and 2 together when the cylindrical parts 1 and 2 are held.

Note that an output shaft 443 provided in the motor 44 is connected to the lower end of the cylindrical portion 421, so that the cylindrical portion 421 is supported by the output shaft 443. Its relationship with the output shaft 443 will be described in detail later.

Although not shown, the laser irradiator 43 includes a laser oscillator such as a CO2 laser, a YAG (Yttrium Aluminum Garnet) laser, a fiber laser, and a disk laser, and converts the laser beam output from the laser oscillator into parallel light with a constant diameter. , and a lens section that converts the light into annular parallel light. The outer diameter of the annular parallel light L is the same as or larger than the outer diameter of the cylindrical portion 1, as shown in FIG. The inner diameter of the annular parallel light L is the same as or smaller than the inner diameter of the cylindrical portion 2. Then, the laser irradiator 43 irradiates the annular parallel light L converted by the lens section toward the holding mechanisms 41 and 42, that is, toward the lower side, as shown in FIG. Thereby, when the cylindrical parts 1 and 2 are held by the holding mechanisms 41 and 42, the laser irradiator 43 emits a laser beam that is annular parallel light L, and the cylindrical ends of the cylindrical parts 1 and 2 are The end face portions 13 and 23 are melted. At this time, the laser irradiator 43 irradiates the laser beam, which is an annular parallel beam L, so that the entire end surface portions of the cylindrical ends 13 and 23 are melted at the same time.

Note that, as shown in FIG. 8, the laser irradiator 43 has an annular shape extending from the direction in which the cylindrical axes of the cylindrical parts 1 and 2 held by the holding mechanisms 41 and 42 extend to the end surfaces of the cylindrical ends 13 and 23. It is desirable to irradiate parallel light L. In other words, it is desirable that the laser irradiator 43 irradiates the annular parallel light L to the end surfaces of the cylindrical ends 13 and 23 from a direction perpendicular to the end surfaces. This is because the laser irradiator 43 can irradiate the entire end surface portions of the cylindrical ends 13 and 23 with parallel light L of uniform intensity.

Returning to FIG. 7, in the melting step of step S1, the end face portions of the cylindrical ends 13 and 23 of the cylindrical parts 1 and 2 are melted using such a welding device 4A. As described above, since the laser irradiator 43 irradiates the annular laser beam, the entire end surface portions of the cylindrical ends 13 and 23 are melted. As a result, a molten pool spanning the cylindrical ends 13 and 23 is formed over the entire circumference.

Next, when irradiation of the laser beam to the end face portions of the cylindrical ends 13 and 23 begins in the melting process, that is, when the end face portions of the cylindrical ends 13 and 23 begin to melt, a rotation process is performed in parallel with the melting of the end face portions. (Step S2).

In this rotation step, the cylindrical portion 2 is rotated in the circumferential direction while the cylindrical portion 1 remains as it is. That is, the cylindrical portion 2 is rotated around the cylindrical axis A shown in FIG. For the rotation of the cylindrical portion 2, the motor 44 provided in the welding device 4A described above is used.

As shown in FIG. 8, the motor 44 includes a case 442, a bearing portion 441 that is provided on the upper side of the case 442, and has a smaller outer diameter than the case 442, and is rotatably held by the bearing portion 441. It has an output shaft 443 that projects upward from the center of the upper end. As described above, the bearing part 441 is fixed to the holding mechanism 41 that holds the cylindrical part 1 by being fitted into the annular flange part 412 of the holding mechanism 41.

On the other hand, the upper end of the output shaft 443 is connected to the holding mechanism 42. Specifically, a mounting hole 424 coaxial with the cylinder axis B is formed in the lower part of the columnar part 421 of the holding mechanism 42 . The upper end of the output shaft 443 is connected to the holding mechanism 42 by being inserted into the attachment hole 424 thereof. Further, the output shaft 443 extends along the cylindrical axis B. Thereby, the output shaft 443 rotates the holding mechanism 42 by rotating itself. Since the holding mechanism 42 holds the cylindrical part 2, when the holding mechanism 42 rotates, the cylindrical part 2 also rotates with the rotation.

In the rotation process, the output shaft 443 of the motor 44 is rotated to rotate the cylindrical portion 2 around the column axis B. For example, the welding device 4A includes a controller 45 shown in FIG. 8 that controls the rotation of the motor 44, and the controller 45 controls the power supply to the motor 44 to rotate the output shaft 443 of the motor 44, thereby rotating the cylindrical portion 2.

In this case, the controller 45 preferably starts supplying power to the motor 44 and rotates the motor 44 when receiving a start signal indicating the start of laser light irradiation from the laser irradiator 43.

Further, the number of rotations of the output shaft 443 of the motor 44, in other words, the number of rotations of the cylindrical portion 2 during the rotation process, is preferably from several rotations/second to several tens of rotations/second, for example. Further, the rotation of the cylindrical portion 2 may be a constant speed rotation in order to facilitate control. Alternatively, rotation with acceleration or deceleration may be used to facilitate generation of convection, which will be described later. The state of the cylindrical parts 1 and 2 during this rotation process is shown in FIGS. 9 and 10.

FIG. 9 is a perspective view of the cylindrical part 2 rotated in the rotation process included in the method for welding the cylindrical parts 1 and 2 according to the first embodiment, and another cylindrical part 1 into which the cylindrical part 2 is fitted. FIG. 10 is an enlarged top view of the cylindrical part 2 rotated in the rotation process included in the welding method and another cylindrical part 1 into which the cylindrical part 2 is fitted. Note that in FIGS. 9 and 10, the shapes of the cylindrical portions 1 and 2 are simplified for easy understanding. Further, the locations where the molten pool 6 is formed are shaded.

As shown in FIG. 9, in the rotation process, the cylindrical part 1 is not rotated, and only the cylindrical part 2 is rotated clockwise in a top view about the cylindrical axis C, for example, as shown by arrow A5. .

The movement of the molten metal at this time will be explained by focusing on portions P10, P20, and P30, which are partial areas within the molten pool 6 shown in FIG. 10. The shapes of the portions P10, P20, and P30 shown in FIG. 10 are the shapes before the cylindrical portion 2 rotates, and the shapes are circular. When the cylindrical portion 2 rotates clockwise in a top view, these portions P10, P20, and P30 are pulled in the clockwise direction and extend in the circumferential direction, and are deformed into the elliptical shapes of the portions P11, P21, and P31. . As a result, convection, ie, forced convection, is generated within the molten pool 6 as indicated by arrows A10, A20, and A30. By generating a flow stronger than the Marangoni convection, pools 61 where a large amount of molten metal locally accumulates are less likely to occur in the molten pool 6. As a result, the amount of molten metal is reduced at locations other than the pooled portion 61, and the welding strength is prevented from decreasing.
In addition, in the rotation of the cylindrical part 2, it is desirable that the end surfaces of the cylindrical end 13 of the cylindrical part 1 and the cylindrical end 23 of the cylindrical part 2 are made horizontal. As a result, it is desirable to make the molten pool 6 horizontal. This is because such an arrangement reduces the influence of gravity on the molten pool 6.

This rotation process continues until the molten metal solidifies. For example, the output shaft 443 of the motor 44 may be kept rotating from the start of rotation, and the motor 44 may be driven until the output shaft 443 stops rotating due to solidification of the molten metal. This is because there is no need to provide a mechanism for detecting solidification of molten metal, and the apparatus can be simplified. In this case, it is preferable that the time required for solidification of the molten metal is determined in advance through experiments, and that the controller 45 drives the motor 44 for a fixed time longer than that time.

When the molten metal solidifies, a weld 5 shown in FIG. 3 is formed. As a result, the cylindrical parts 1 and 2 are welded. This completes the welding method for the cylindrical parts 1 and 2.

Note that the hot water storage tank 10 and nipple 20 described in Embodiment 1 are examples of the first member and the second member in the present disclosure. Further, the cylindrical portion 1 of the hot water storage tank 10 and the cylindrical portion 2 of the nipple 20 are examples of the first cylindrical portion and the second cylindrical portion in the present disclosure. Further, the cylindrical end 13 of the cylindrical portion 1 and the cylindrical end 23 of the cylindrical portion 2 are examples of a first cylindrical end and a second cylindrical end in the present disclosure. The melting step is an example of a step of forming a molten pool spanning the first cylindrical end and the second cylindrical end over the entire circumference as referred to in the present disclosure. Further, the rotation step is an example of a step of rotating at least one of the first cylindrical portion and the second cylindrical portion in the circumferential direction in the present disclosure.

Furthermore, the through-hole 12 formed in the wall portion 11 of the hot water storage tank 10 is an example of a through-hole formed in a plate-shaped portion as referred to in the present disclosure. The cylindrical portion 1 formed by burring is an example of a burring portion in the present disclosure. The through hole 12 surrounded by the cylindrical portion 1 is an example of an inlet/outlet for hot water or water in a hot water tank as referred to in the present disclosure. The nipple 20 is an example of piping in the present disclosure. Further, the holding mechanisms 41 and 42 and the laser irradiator 43 provided in the welding device 4A are examples of a first holding mechanism, a second holding mechanism, and a heating mechanism in the present disclosure.

As described above, in the method for welding the cylindrical parts 1 and 2 according to the first embodiment, the cylindrical part 2 is rotated in the circumferential direction in parallel with the melting of the end face portions of the cylindrical ends 13 and 23 of the cylindrical parts 1 and 2. let As a result, centrifugal force acts on the molten metal due to the rotation of the cylindrical portion 2, and the molten metal convects in the circumferential direction. This prevents the molten metal from concentrating in some areas and causing a shortage of molten metal in other areas. As a result, the welding strength between the cylindrical parts 1 and 2 is prevented from decreasing. According to this welding method, the cylindrical parts 1 and 2 can be welded with sufficient welding strength.

Furthermore, in the method for welding the cylindrical parts 1 and 2 according to the first embodiment, the rotation of the cylindrical part 2 starts from the start of laser light irradiation and continues until the molten metal solidifies. Therefore, the molten metal generated by laser beam irradiation can be rapidly convected, and the molten metal can continue to be convected while the molten metal is present. As a result, it is possible to more effectively prevent the molten metal from concentrating in some areas and causing a shortage of molten metal in other areas.

(Modified example)
In the method of welding the cylindrical parts 1 and 2 according to the first embodiment, the cylindrical part 2 is rotated in the rotation step, but the method of welding the cylindrical parts 1 and 2 is not limited to this. In the method of welding the cylindrical parts 1 and 2, at least one of the cylindrical parts 1 and 2 may be rotated in the circumferential direction in the rotation step. Therefore, in the rotation step, the cylindrical portion 1 may be rotated instead of the rotation of the cylindrical portion 2 described in the first embodiment. This is because even with such a configuration, it is possible to cause convection of the molten metal and prevent the molten metal from concentrating in a certain area.

(Embodiment 2)
As described above, in the method of welding the cylindrical parts 1 and 2, at least one of the cylindrical parts 1 and 2 may be rotated in the circumferential direction in the rotation step. Therefore, in the method for welding the cylindrical parts 1 and 2 according to the second embodiment, both the cylindrical parts 1 and 2 are rotated in the rotation process. A method of welding cylindrical parts 1 and 2 according to the second embodiment will be described below with reference to FIGS. 11 to 14. In Embodiment 2, a description will be given focusing on configurations that are different from Embodiment 1.

FIG. 11 is a perspective view of two cylindrical parts 1 and 2 rotated in a rotation process included in the welding method for cylindrical parts 1 and 2 according to embodiment 2. FIG. 12 is an enlarged top view of cylindrical parts 1 and 2 rotated in a rotation process included in the welding method. FIG. 13 is a flowchart of the welding method for cylindrical parts 1 and 2 according to embodiment 2. FIG. 14 is a top view of cylindrical parts 1 and 2 irradiated with laser light by laser irradiator 43 in the melting process included in the welding method. Note that in FIGS. 11 and 12, as in FIGS. 9 and 10, the shapes of cylindrical parts 1 and 2 are simplified to make it easier to understand. Also, the area where molten pool 6 is formed is shaded. Meanwhile, in FIG. 14, the irradiation area IR is hatched to show the area irradiated with laser light.

As shown in FIG. 11, in the method of welding the cylindrical parts 1 and 2 according to the second embodiment, in the rotation process, the cylindrical parts 1 and 2 are welded around the cylindrical axis C, which is the central axis of the cylindrical parts 1 and 2. Rotate both.

Specifically, in the rotation step, the cylindrical portion 1 is rotated counterclockwise when viewed from above, as shown by arrow A6. Further, the cylindrical portion 2 is rotated clockwise when viewed from above, as shown by arrow A5. Then, the rotational speeds of the cylindrical parts 1 and 2 are set to different rotational speeds. For example, the rotational speed of the cylindrical portion 1 is made higher than the rotational speed of the cylindrical portion 2.

The movement of the molten metal at this time will be explained by focusing on portions P10, P20, and P30, which are partial areas within the molten pool 6 shown in FIG. 12. The shapes of the portions P10, P20, and P30 shown in FIG. 12 are the shapes before each of the cylindrical portions 1 and 2 are rotated, and the shapes are circular. These portions P10, P20, and P30 are pulled in the clockwise direction and the counterclockwise direction when viewed from above, as the cylindrical portions 1 and 2 rotate in the above-mentioned directions during the rotation process. As a result, the portions P10, P20, and P30 are deformed into the elliptical shapes of the portions P12, P22, and P32. Since the rotational speed of either of the cylindrical parts 1 and 2 is high, forced convection is generated in the molten pool 6 in the direction in which either of them rotates. For example, when the rotational speed of the cylindrical portion 1 is higher than the rotational speed of the cylindrical portion 2, forced convection occurs in the direction in which the cylindrical portion 1 rotates, as shown by arrows A11, A21, and A31. If the forced convection is stronger than the Marangoni convection, the accumulation 61 will be less likely to occur in the molten pool 6. As a result, similarly to the first embodiment, the method for welding the cylindrical parts 1 and 2 according to the second embodiment prevents the amount of molten metal from decreasing at locations other than the pool part 61, and increases the welding strength. suppresses the decline in

In the method for welding the cylindrical parts 1 and 2 according to the second embodiment, such a rotation process is started before the melting process is performed, as shown in FIG. 13 (step S21). This is to uniformly apply the laser light emitted by the laser irradiator 43 to the cylindrical ends 13 and 23 of the cylindrical parts 1 and 2 during the melting process.

To explain in detail, in the melting process, for example, the optical axis of the laser beam is tilted with respect to the cylindrical ends 13, 23 of the cylindrical parts 1, 2, so that the annular irradiation area of the laser beam has a width over the entire circumference. The shape of the ring may no longer be uniform. Specifically, as shown in FIG. 14, the annular irradiation area IR of the laser beam has a circular shape that is narrow in one part in the circumferential direction and wide in another part in the circumferential direction. be. When the laser beam is irradiated in such an irradiation area, melting progresses in parts of the cylindrical ends 13 and 23 of the cylindrical parts 1 and 2, and more molten metal is generated, and less molten metal is generated in other parts. It ends up. Moreover, the molten metal tends to become high in some parts of the cylinder ends 13 and 23 and low in other parts, making it easy for the pooled portion 61 to occur due to the above-mentioned Marangoni convection.

In order to solve this problem, in the method for welding the cylindrical parts 1 and 2 according to the second embodiment, as shown in FIG. 13, the rotation process is started before the melting process. Since the cylindrical parts 1 and 2 are rotated in the rotation process, the amount of laser light irradiated to each portion in the circumferential direction of the cylindrical ends 13 and 23 of the cylindrical parts 1 and 2 in the melting process is made uniform. As a result, the amount of melting at each portion in the circumferential direction of the cylindrical ends 13, 23 becomes uniform, making it difficult for the above-described pooled portion 61 to occur. Further, the temperature of each portion in the circumferential direction of the cylindrical ends 13 and 23 is also made uniform. As a result, the occurrence of pooled portions 61 due to Marangoni convection becomes less likely to occur. As a result, the method for welding the cylindrical parts 1 and 2 according to the second embodiment prevents the amount of molten metal from decreasing in a portion of the circumferential direction of the cylindrical ends 13 and 23, thereby preventing the welding strength from decreasing. suppress.

Note that the rotational speed of the cylindrical parts 1 and 2 is preferably such that the cylindrical parts 1 and 2 rotate one or more times during the melting process. This is because at such a speed, the amount of laser light irradiated onto each circumferential portion of the cylindrical ends 13 and 23 of the cylindrical portions 1 and 2 can be made uniform. Further, the cylindrical parts 1 and 2 may be rotated relative to the laser irradiator 43, specifically, relative to the optical axis of the laser beam. This is because such rotation makes the amount of laser light irradiation uniform.

This rotation process is ended after the melting process in order to force convection of the molten metal as much as possible during melting (step S22). For example, the rotation process may be continued until the molten metal solidifies after the melting process, and then terminated. Thereby, the rotation process suppresses the amount of molten metal from decreasing in a portion of the circumferential direction of the cylindrical ends 13, 23 as much as possible, thereby preventing a decrease in welding strength.

Note that the cylindrical parts 1 and 2 described in Embodiment 2 are examples of the first cylindrical part and the second cylindrical part in the present disclosure. Further, the counterclockwise direction in which the cylindrical portion 1 rotates when viewed from above is an example of one direction in the circumferential direction in the present disclosure. The clockwise direction in which the cylindrical portion 2 rotates when viewed from above is an example of the other direction of the circumferential direction in the present disclosure.

As described above, in the method of welding the cylindrical parts 1 and 2 according to the second embodiment, the cylindrical part 1 is rotated in the counterclockwise direction when viewed from above in the rotation process, and the cylindrical part 2 is rotated clockwise when viewed from the top. Rotate in the direction of. Therefore, forced convection of molten metal occurs at the cylindrical ends 13 and 23 of the cylindrical parts 1 and 2, respectively. As a result, the method for welding the cylindrical parts 1 and 2 according to the second embodiment prevents the molten metal from concentrating in some areas of the cylindrical ends 13 and 23 and causing a shortage of molten metal in other areas. prevent. Further, a decrease in welding strength between the cylindrical parts 1 and 2 can be suppressed.

In the rotation process, since the rotational speed of the cylindrical portion 1 and the rotational speed of the cylindrical portion 2 are different, the molten metal in the molten pool 6 is forced to convect toward the faster rotational speed as a whole. As a result, molten metal is less likely to be unevenly distributed in some regions of the cylindrical ends 13 and 23. In the method of welding the cylindrical parts 1 and 2 according to the second embodiment, a decrease in the welding strength of the cylindrical parts 1 and 2 can be suppressed.

Moreover, since the rotation process is performed before the melting process, the amount of laser light irradiated to each of the cylindrical ends 13 and 23 of the cylindrical parts 1 and 2 can be made uniform. As a result, in the rotation step, the melt amount and temperature at each circumferential portion of the cylindrical ends 13 and 23 can be made uniform, and uneven distribution of molten metal can be suppressed. As a result, the rotation process can suppress a decrease in welding strength between the cylindrical parts 1 and 2.

(Modified example)
In the method of welding the cylindrical parts 1 and 2 according to the second embodiment, the cylindrical parts 1 and 2 are rotated in opposite directions in the rotation process, but the method of welding the cylindrical parts 1 and 2 is not limited to this. In the method of welding the cylindrical parts 1 and 2, as explained in the first embodiment, at least one of the cylindrical parts 1 and 2 may be rotated in the circumferential direction in the rotation step. Therefore, as long as this is satisfied, the rotation direction is not limited. For example, in the rotation process, the cylindrical parts 1 and 2 may rotate in the same direction.

FIG. 15 is a perspective view of two cylindrical parts 1 and 2 that are rotated in a modification of the rotation process included in the method for welding cylindrical parts 1 and 2 according to the second embodiment.

In the rotation step, as shown in FIG. 15, both the cylindrical parts 1 and 2 may be rotated clockwise when viewed from above. In this case, it is preferable that the rotational speed of the cylindrical portion 1 is faster than the rotational speed of the cylindrical portion 2, as shown by arrows A5 and A7. Alternatively, although not shown, the rotational speed of the cylindrical portion 1 may be slower than the rotational speed of the cylindrical portion 2. In short, the rotational speeds of the cylindrical portions 1 and 2 may be different. With this configuration, the laser beam can be applied uniformly to each of the cylindrical ends 13 and 23 of the cylindrical parts 1 and 2 in the melting process, and the molten metal in the molten pool 6 can be forced to convect in the rotation process. This is because it is possible.

Note that, of course, both the cylindrical parts 1 and 2 may be rotated counterclockwise when viewed from above.

Furthermore, when both cylindrical parts 1 and 2 are rotated clockwise or counterclockwise when viewed from above, that is, when cylindrical parts 1 and 2 are rotated in the same direction, cylindrical parts 1 and 2 rotate at the same speed. You can. Even with such rotation, forced convection of the molten metal in the molten pool 6 can be achieved by accelerating and decelerating the rotation. Further, when acceleration and deceleration are not performed, forced convection of the molten metal is not possible, but the cylindrical ends 13 and 23 of the cylindrical parts 1 and 2 can be uniformly irradiated with laser light.

(Embodiment 3)
The welding device 4A used in the method of welding the cylindrical parts 1 and 2 according to the first embodiment includes holding mechanisms 41 and 42, and these holding mechanisms 41 and 42 hold the cylindrical part 1 of the hot water storage tank 10 by the magnetic force of the magnets 414 and 423. and holds the cylindrical portion 2 of the nipple 20. However, the holding mechanisms 41 and 42 are not limited to this. In the welding device 4A, the holding mechanism 41 should just hold the cylindrical part 1. In that case, the holding mechanism 42 holds the cylindrical part 2 fitted in the cylindrical part 1, and the cylindrical end 13 which the cylindrical part 1 has. It is sufficient that the end surfaces of the cylindrical end 23 of the cylindrical portion 2 are held in the same state.

Here, aligning the end surfaces of the cylindrical end 13 and the cylindrical end 23 means aligning the positions so that there is only a difference in level between these end surfaces to the extent that a molten pool is formed across these end surfaces during the melting process. Say something.

In the welding device 4B used in the method of welding the cylindrical parts 1 and 2 according to the third embodiment, the holding mechanisms 41 and 42 hold the cylindrical parts 1 and 2 by the urging force of a spring. Hereinafter, a method for welding cylindrical parts 1 and 2 according to the third embodiment will be described with reference to FIG. 16. In Embodiment 3, a description will be given focusing on a configuration different from Embodiments 1 and 2.

FIG. 16 is a sectional view of a welding device 4B used in the method of welding the cylindrical parts 1 and 2 according to the third embodiment.

As shown in FIG. 16, the large cylindrical portion 411 included in the holding mechanism 41 has a rib 415 that extends along the outer peripheral surface of the large cylindrical portion 411 to above the upper end surface of the large cylindrical portion 411. A spring 416 is provided at the upper end of the rib 415 to bias the holding portion 417 toward the cylindrical end 413 of the large cylindrical portion 411. In the holding mechanism 41, as described in the first embodiment, the wall portion 11 of the hot water storage tank 10 can be placed on the cylindrical end 413 of the large cylindrical portion 411. In the holding mechanism 41, when the wall portion 11 of the hot water storage tank 10 is placed on the cylindrical end 413 of the large cylindrical portion 411, the spring 416 presses the clamping portion 417 against the wall portion 11. As a result, the wall portion 11 is sandwiched between the holding portion 417 and the cylindrical end 413 of the large cylindrical portion 411. As a result, the holding mechanism 41 holds the wall portion 11 of the hot water storage tank 10.

On the other hand, the columnar portion 421 of the holding mechanism 42 is provided with a through hole 425 that penetrates the columnar portion 421 in the horizontal direction. Inside the through hole 425, a pressing member 426 is provided on one opening side, and a pressing member 427 is provided on the other opening side. A spring 428 is provided between the pressing members 426 and 427 to urge the pressing members 426 and 427 toward the respective openings. In the holding mechanism 42, as described in the first embodiment, the cylindrical portion 421 can be fitted into the cylindrical portion 2 of the nipple 20 when the cylindrical portion 2 is covered therewith. In the cylindrical portion 421, when the cylindrical portion 2 of the nipple 20 is fitted over the cylindrical portion 2, the spring 428 urges the pressing members 426 and 427 toward the inner wall surface of the cylindrical portion 2. As a result, the pressing members 426 and 427 are pressed against the inner wall surface of the cylindrical portion 2. As a result, the holding mechanism 42 holds the cylindrical portion 2 of the nipple 20.

As described above, in the welding device 4B used in the method of welding the cylindrical parts 1 and 2 according to the third embodiment, the holding mechanism 41 includes the spring 416 that presses the clamping part 417 against the wall part 11 of the hot water storage tank 10. Further, the holding mechanism 42 includes a spring 428 that presses pressing members 426 and 427 against the inner wall surface of the cylindrical portion 2 of the nipple 20. As a result, even if the wall portion 11 of the hot water storage tank 10 and the cylindrical portion 2 of the nipple 20 are made of a material that does not generate magnetism and does not stick to the magnets 414, 423, such as austenitic stainless steel or aluminum alloy, welding The device 4B can hold the wall portion 11 of the hot water storage tank 10 and the cylindrical portion 2 of the nipple 20.

(Embodiment 4)
In Embodiment 1-3, a cylindrical part 1 is provided at the water inlet of a hot water storage tank 10 provided in a water heater and formed by burring, and a cylindrical part 2 is provided at the tip of a nipple 20 and forms a circular pipe. The configuration of the welding method for the cylindrical parts 1 and 2 will be explained by taking as an example the case where the cylindrical parts 1 and 2 are welded. However, the method of welding the cylindrical parts 1 and 2 is not limited to this. The method for welding the cylindrical parts 1 and 2 may be to weld the cylindrical parts 1 and 2, and in addition to these, other cylindrical parts may be welded.

The method of welding the cylindrical parts 1 and 2 according to the fourth embodiment is a method of welding the cylindrical part 3 to the cylindrical parts 1 and 2. A method of welding the cylindrical portion 1-3 according to the fourth embodiment will be described below with reference to FIG. 17. In Embodiment 4, a description will be given focusing on configurations that are different from Embodiments 1-3.

FIG. 17 is a cross-sectional view of a hot water storage tank 30 including a cylindrical portion 1-3 welded by the method of welding the cylindrical portion 1-3 according to the fourth embodiment.

In the hot water storage tank 30 shown in FIG. 17, a cylindrical portion 2, which is a circular pipe and can be fitted into the cylindrical portion 1, is inserted into the cylindrical portion 1 provided at the water supply port. The end surface of the cylindrical end 23 of the cylindrical portion 2 is aligned with the end surface of the cylindrical end 13 of the cylindrical portion 1 in the direction of the cylinder axis C. Further, in the hot water storage tank 30 , a cylindrical portion 3 that is included in the joint 31 and that can be fitted into the cylindrical portion 2 is inserted into the cylindrical portion 2 . The end surface of the cylindrical end 33 of the cylindrical portion 3 is aligned with the end surface of the cylindrical end 23 of the cylindrical portion 2 or the end surface of the cylindrical end 13 of the cylindrical portion 1 in the direction of the cylinder axis C. The cylindrical parts 1-3 arranged in this manner are joined to each other by welds 5 formed at the cylindrical ends 13, 23, and 33.

Such welding of the cylindrical portion 1-3 is realized by applying the method of welding the cylindrical portions 1 and 2 described in Embodiment 1-3. To explain the method of welding the cylindrical portion 1-3 in detail, first, the cylindrical portion 1-3 is assembled in the above-described arrangement. Then, the melting process described in Embodiment 1-3 is applied to the combined cylindrical portion 1-3 to melt the cylindrical ends 13, 23, and 33 of the cylindrical portion 1-3. Specifically, the cylindrical ends 13, 23, 33 are irradiated with a laser beam using the laser irradiator 43 to melt the end surface portions of the cylindrical ends 13, 23, 33. As a result, a molten pool 6 is formed at the cylindrical ends 13, 23, and 33.

Subsequently, at least one of the cylindrical parts 1-3 is rotated around the cylindrical axis C by applying the rotation process described in Embodiment 1-3. For example, as described in Embodiment 1, when irradiation of the laser beam to the end face portions of the cylindrical ends 13, 23, and 33 begins in the melting process, in parallel with the irradiation of the laser beam, the cylindrical portions 1, 3 , and rotate only the cylindrical portion 2 clockwise around the cylindrical axis C when viewed from above. The rotation of the cylindrical portion 2 is continued until the laser beam irradiation is finished and the molten metal in the molten pool 6 is solidified.

A welded portion 5 is formed in the cylindrical portion 1-3 by solidifying the molten metal. As a result, the cylindrical portion 1-3 is welded. When the cylindrical portions 1-3 are welded, only the cylindrical portion 2 cannot be rotated, and as a result, the rotation of the cylindrical portion 2 is stopped. This completes the welding method for the cylindrical portion 1-3.

As described above, in the welding method for the cylindrical portion 1-3 according to the fourth embodiment, after the cylindrical ends 13, 23, and 33 of the cylindrical portion 1-3 are melted to form the molten pool 6 in the melting step, the cylindrical portion 1-3 is welded. Until the molten metal in the pool 6 solidifies, at least one of the cylindrical parts 1-3 is rotated around the cylindrical axis C. Therefore, as in the first and second embodiments, molten metal is forced to convect in the direction of rotation of at least one of the cylindrical portions 1-3. As a result, in the method for welding the cylindrical portion 1-3 according to the fourth embodiment, molten metal is concentrated in some areas of the cylindrical ends 13, 23, and 33, and molten metal is insufficient in other areas. prevent that. Moreover, according to this welding direction, a decrease in the welding strength of the cylindrical parts 1 and 2 can be suppressed.

In addition, in the welding method of the cylindrical part 1-3 according to the fourth embodiment, it is illustrated that only the cylindrical part 2 is rotated while the cylindrical parts 1 and 3 are left as they are in the rotation process. The cylindrical parts 2 and 3 may be rotated, or each of the cylindrical parts 1-3 may be rotated. In short, in the method of welding the cylindrical parts 1-3 according to the fourth embodiment, it is sufficient to rotate at least one of the cylindrical parts 1-3 around the cylindrical axis C. In that case, the rotation direction may be either clockwise or counterclockwise when viewed from above.

(Modified example)
Furthermore, in the method of welding the cylindrical portion 1-3 according to the fourth embodiment, the cylindrical portion 1 provided at the water supply port of the hot water storage tank 30 is joined to the cylindrical portion 2, which is a circular pipe, and the cylindrical portion 3 provided in the joint 31. It is applied to the manufacturing method of water heaters that are assembled. However, the method of welding the cylindrical portion 1-3 according to the fourth embodiment is not limited to this. The welding method of the cylindrical part 1-3 according to the fourth embodiment is a method for welding a cylindrical part 1-3 of a compressor, in which a cylindrical part 2, which is piping, and a cylindrical part 3, which is provided in a joint 31, are assembled to a cylindrical part 1 provided in a housing provided in the compressor. may be applied to the manufacturing method. Naturally, the method of welding the cylindrical portion 1-3 according to Embodiment 1-3 may also be applied to the method of manufacturing a compressor. For example, the method for welding the cylindrical portion 1-3 according to Embodiment 1-3 is applied to a method for manufacturing a compressor in which a cylindrical portion 2, which is a pipe, is assembled to a cylindrical portion 1 provided in a housing of the compressor. Good too.

(Embodiment 5)
In the method for welding the cylindrical parts 1 and 2 according to Embodiment 1-3, the end face portions of the cylindrical end 13 of the cylindrical part 1 and the cylindrical end 23 of the cylindrical part 2 are directly melted to weld the cylindrical parts 1 and 2. do. Further, in the method of welding the cylindrical portion 1-3 according to the fourth embodiment, the end surface portions of the cylindrical ends 13 and 23 and the end surface portion of the cylindrical end 33 of the cylindrical portion 3 are directly melted to form the cylindrical portion 1-3. to weld. However, the method of welding the cylindrical parts 1 and 2 and the method of welding the cylindrical part 1-3 are not limited to these. The cylindrical parts 1 and 2 may be welded by melting an annular member that is brought into contact with the end surface portions of the cylindrical ends 13 and 23, and by melting the cylindrical ends 13 and 23 with the heat of melting the annular member. . Alternatively, the method for welding the cylindrical portion 1-3 is to melt a circular member that is in contact with the end surface portion of the cylindrical ends 13, 23, 33, and use the heat of melting of the circular member to attach the cylindrical ends 13, 23, 33 may be melted.

The method for welding the cylindrical parts 1 and 2 according to the fifth embodiment is to weld the cylindrical ends 13, 23 by melting the annular member that is brought into contact with the end face portions of the cylindrical ends 13, 23 of the cylindrical parts 1, 2. This is a method of welding the cylindrical parts 1 and 2 by melting the end face portions of the cylindrical parts 1 and 2. A method of welding cylindrical parts 1 and 2 according to the fifth embodiment will be described below with reference to FIGS. 18 to 20. In Embodiment 5, a description will be given focusing on configurations that are different from Embodiments 1-4.

FIG. 18 is a flowchart of a method for welding the cylindrical parts 1 and 2 according to the fifth embodiment. FIG. 19 is a cross-sectional view of the cylindrical parts 1 and 2 to which the annular member 7 is attached in the annular member attachment process included in the welding method for the cylindrical parts 1 and 2. FIG. 20 is a sectional view of the cylindrical parts 1 and 2 in which the molten pool 6 is formed in the welding process included in the welding method for the cylindrical parts 1 and 2.

As shown in FIG. 18, in the method for welding the cylindrical parts 1 and 2 according to the fifth embodiment, first, an attachment step is performed to attach the annular member 7 (step S50).

Specifically, an annular member 7 having the same outer diameter and inner diameter as the annular end face portion formed by combining the cylindrical end 13 of the cylindrical portion 1 and the cylindrical end 23 of the cylindrical portion 2 is prepared. This is because the annular member 7 having such a shape can cover the above-mentioned annular end surface portion. Furthermore, a member made of the same metal material as the metal material forming the cylindrical parts 1 and 2 is prepared as the annular member 7. This is because if such a material is used, the material melted in the melting process can be used as a welding material for welding the cylindrical parts 1 and 2.

Subsequently, as shown in FIG. 19, the prepared annular member 7 is placed over the end surfaces of the cylindrical ends 13 and 23. At this time, the central axis AL of the annular member 7 and the cylindrical axes C of the cylindrical ends 13 and 23 are aligned, and the annular surface of the annular member 7 is brought into contact with the end surface portions of the cylindrical ends 13 and 23. It is preferable to cover the end surfaces of the cylindrical ends 13 and 23 with the annular member 7. Thereby, the annular member 7 is attached to the cylindrical parts 1 and 2.

In this state, a melting process is performed to melt the annular member 7 and the welded parts of the cylindrical parts 1 and 2 shown in FIG. 18 (step S51).

Specifically, in step S50, the annular member 7 placed over the end surface portions of the cylindrical ends 13 and 23 is melted. In this melting step, for example, the welding device 4A including the laser irradiator 43 described in Embodiment 1 is used. Then, the annular member 7 is heated by the welding device 4A, and the end surface portions of the cylindrical ends 13 and 23 are melted by the heat of the molten metal formed by the heating. Thereby, as shown in FIG. 20, a molten pool 6 is formed spanning the cylindrical ends 13 and 23. The molten pool 6 is formed over the entire circumference of the cylindrical ends 13 and 23.

Note that in the melting step, as shown in FIG. 20, the annular member 7 may be completely melted, or only a portion of the annular member 7 may be melted. Furthermore, the molten pool 6 may include a portion of the annular member 7 that remains unmelted.

Returning to FIG. 18, when the annular member 7 and the end face portions of the cylindrical ends 13 and 23 begin to melt, a rotation process is performed in parallel with the melting process (step S52).

In this rotation step, at least one of the annular member 7 and the cylindrical parts 1 and 2 is rotated in the circumferential direction. For example, when using the welding apparatus 4A described in Embodiment 1, when laser irradiation from the laser irradiator 43 starts, the output shaft 443 of the motor 44 of the holding mechanism 42 is By rotating , the cylindrical portion 2 is rotated around the cylindrical axis C. That is, the cylindrical portion 2 is rotated in the circumferential direction.

This rotation of the cylindrical portion 2 continues until the laser irradiation from the laser irradiator 43 ends and the molten metal forming the molten pool 6 solidifies. For example, the rotation of the cylindrical portion 2 is continued for a while after the laser irradiation by the laser irradiator 43 by rotating the output shaft 443 of the motor 44 of the holding mechanism 42 . The rotation of the cylindrical portion 2 is continued until the molten metal solidifies, the annular member 7 and the cylindrical portions 1 and 2 are welded together, and the output shaft 443 of the motor 44 becomes unable to rotate.

When the molten metal forming the molten pool 6 solidifies, welds are formed at the cylindrical ends 13 and 23, although not shown in FIG. As a result, the cylindrical parts 1 and 2 are welded. Alternatively, the cylindrical portions 1 and 2 and the annular member 7 remaining without being melted are welded. This completes the welding method for the cylindrical parts 1 and 2.

The welded portion formed by the method of welding the cylindrical parts 1 and 2 is also formed between the cylindrical parts 1 and 2. Alternatively, welds are also formed between the annular member 7 and the cylindrical part 1, between the annular member 7 and the cylindrical part 2, and between the cylindrical parts 1 and 2. Therefore, even if a gap occurs between the cylindrical parts 1 and 2 due to variations in assembly and manufacturing, the welding part will fit into the gap, so the cylindrical parts 1 and 2 can be welded with high strength. Alternatively, even if a step occurs between the cylindrical end 13 of the cylindrical portion 1 and the cylindrical end 23 of the cylindrical portion 2, the welded portion covers the step and closes the gap with the annular member 7 caused by the step. As a result, the annular member 7 and the cylindrical parts 1 and 2 can be welded with high strength.

As described above, in the method of welding the cylindrical parts 1 and 2 according to the fifth embodiment, the annular member 7 is brought into contact with the end face parts of the cylindrical ends 13 and 23 of the cylindrical parts 1 and 2, and the end face parts By covering the annular member 7 with the annular member 7 and then melting the annular member 7, the cylindrical ends 13 and 23 are melted by the heat of melting the annular member 7. As a result, a sufficient amount of molten metal is supplied. Thereby, even if there is a gap between the cylindrical parts 1 and 2, welding can be performed with high strength.

(Modified example)
Although the annular member 7 described in the fifth embodiment has the shape of a thin annular plate, the shape of the annular member 7 is not limited to this.

FIG. 21 is a cross-sectional view of a modification of the annular member 7 and the cylindrical parts 1 and 2 used in the cylindrical part welding method according to the fifth embodiment. FIG. 22 is a sectional view of another modification of the annular member 7 and the cylindrical parts 1 and 2.

As shown in FIG. 21, the annular member 7 may have an outer peripheral wall portion 71 that protrudes downward along the outer periphery. The outer peripheral wall portion 71 may cover the outer peripheral wall of the cylindrical portion 1 and be locked to the cylindrical portion 1 when the annular member 7 is placed over the cylindrical ends 13 and 23 of the cylindrical portions 1 and 2. . In short, it is preferable that the cylindrical portion 1 be fitted into the outer peripheral wall portion 71 .

Furthermore, as shown in FIG. 22, the annular member 7 may have an inner circumferential wall portion 72 that protrudes downward along the outer circumference. The inner peripheral wall portion 72 may fit into the internal space of the cylindrical portion 2 when the annular member 7 is placed over the cylindrical ends 13 and 23 of the cylindrical portions 1 and 2.

In this way, the annular member 7 is not limited to the shape of an annular thin plate. The annular member 7 may have an annular shape that covers at least the boundary between the cylindrical ends 13 and 23.

The welding method for the cylindrical portion 1-3, the method for manufacturing a water heater, the method for manufacturing a compressor, and the welding devices 4A and 4B according to Embodiment 1-5 of the present disclosure have been described above. The welding method, the water heater manufacturing method, the compressor manufacturing method, and the welding devices 4A and 4B are not limited to these.

For example, in the first embodiment, the rotation process is performed after the irradiation of the laser beam onto the cylindrical ends 13 and 23 of the cylindrical parts 1 and 2 is started. Furthermore, in the second embodiment, a rotation process is performed before the start of irradiation with the laser beam. However, the welding method for the cylindrical portion 1-3 is not limited to these. In the method for welding the cylindrical portions 1-3, the rotation step may be a step of rotating at least one of the cylindrical portions 1-3 in the circumferential direction at least after the molten pool 6 is formed until it solidifies. .

Here, the cylindrical portion 1-3 refers to a hollow circular cylinder. In this specification, the cylindrical portion 1-3 may include a circular cylinder whose length in the direction of the cylinder axis C is smaller than the outer diameter, in other words, a ring. Further, the cylindrical portion 1-3 may include a conical cylinder whose thickness becomes thinner toward the distal end or the proximal end.

As mentioned above, the rotation step may be a step of rotating at least one of the cylindrical portions 1-3 in the circumferential direction at least between the formation of the molten pool 6 and the solidification thereof. The timing is arbitrary as long as this condition is satisfied. For example, the rotation process may be performed at the same time as the irradiation of laser light onto the cylindrical ends 13, 23, and 33 of the cylindrical portion 1-3 starts.

In addition, when performing the rotation process after the start of irradiation of the laser beam to the cylindrical ends 13, 23, and 33 of the cylindrical part 1-3, the rotation process is started after the start of the irradiation of the laser beam and before the molten metal is generated. It's good to do that. If the rotation step is started at such a timing, the rotation can be reliably performed during the necessary period, and the rotation time can be shortened.

Furthermore, in Embodiment 1-5, the rotation step is performed until the molten metal solidifies. However, the welding method for the cylindrical portion 1-3 is not limited to these. In the method for welding the cylindrical portions 1-3, as described above, the rotation step includes rotating at least one of the cylindrical portions 1-3 in the circumferential direction at least after the molten pool 6 is formed until it solidifies. Any process is fine. Therefore, the rotation step may be completed before the molten metal solidifies. For example, when at least one of the cylindrical parts 1-3 is rotated in the circumferential direction in the rotation process, the rotation is performed by a servo motor, and the servo motor is controlled to stop the molten metal at a predetermined stop before solidifying the molten metal. Rotation may be stopped at the position. With this configuration, when at least one of the cylindrical parts 1-3 to be rotated has a structure, for example, a screw hole, in the circumferential direction, welding can be performed with the structure in a fixed position.

In Embodiment 1-5, the rotation process ends when the molten metal becomes unrotatable due to solidification, but in this case, since the stop position cannot be controlled, the rotationally symmetrical cylindrical part 1-3 It is desirable to apply.

Furthermore, in Embodiment 1-5, melting of the cylindrical ends 13, 23, and 33 of the cylindrical portion 1-3 in the melting process is achieved by irradiation with laser light. However, the welding method for the cylindrical portion 1-3 is not limited to these. The welding method for the cylindrical portion 1-3 is a step of melting the cylindrical ends 13, 23, 33 of the cylindrical portion 1-3 to form a molten pool 6 extending over the cylindrical ends 13, 23, 33 over the entire circumference. good. Therefore, any method may be used to melt the cylindrical ends 13, 23, and 33 as long as this condition is satisfied. For example, the cylindrical ends 13, 23, 33 may be melted by an electron beam.

Furthermore, in the first and second embodiments, the cylindrical parts 1 and 2 are made of a steel material. However, the cylindrical parts 1 and 2 are not limited to this. The cylindrical parts 1 and 2 may be of any type as long as the cylindrical end 13 of the cylindrical part 1 and the cylindrical end 23 of the cylindrical part 2 fitted into the cylindrical part 1, whose end surfaces are aligned with the cylindrical end 13, can be melted. . Therefore, as long as this condition is satisfied, the material of the cylindrical parts 1 and 2 is arbitrary. For example, the cylindrical parts 1 and 2 may be made of pure aluminum or an aluminum alloy. Further, the cylindrical portion 3 described in the fourth embodiment may be made of any material as long as it satisfies the same conditions as the cylindrical portions 1 and 2, and the cylindrical portion 3 may be made of steel, pure aluminum, or an aluminum alloy. .

In Embodiment 1-5, the cylindrical axis C of the cylindrical portion 1-3 is oriented in the vertical direction, and the end surfaces of the cylindrical ends 13, 23, and 33 are oriented in the horizontal direction. The orientations of the end faces of the cylindrical portion 1-3 and the cylindrical ends 13, 23, and 33 are not limited to this. The orientation of the end faces of the cylindrical portion 1-3 and the cylindrical ends 13, 23, and 33 is arbitrary as long as the mutual positional relationship is maintained. The Marangoni convection that generates the pooled portion 61 may also flow in a direction against gravity if there is a temperature distribution in the molten metal within the molten pool 6. Therefore, the method of welding the cylindrical portion 1-3 is also applicable to a configuration in which the end surfaces of the cylindrical ends 13, 23, and 33 are oriented in a direction other than the horizontal direction. For example, the welding method for the cylindrical portion 1-3 can also be applied to a configuration in which the end surfaces of the cylindrical ends 13, 23, and 33 are oriented vertically, and the cylindrical axis C of the cylindrical portion 1-3 is oriented horizontally.

In Embodiments 1-3 and 5, the method of welding the cylindrical parts 1 and 2 is applied to the assembly of the hot water storage tank 10 and nipple 20 of the water heater. In a modification of the fourth embodiment, the welding method for the cylindrical portion 1-3 is applied to the assembly of the compressor housing and piping, or the assembly of the housing, piping, and joint 31. As described above, the method of welding the cylindrical portion 1-3 is applicable to general welding of the cylindrical portion 1-3 in which the end surfaces of the cylindrical ends 13, 23, and 33 are aligned and the end surfaces are joined.

In Embodiment 1-5, the cylindrical portion 1 to be welded surrounds the water supply port of the hot water storage tank 10, but the cylindrical portion 1 is not limited to this, and the cylindrical portion 1 may be provided in the hot water storage tank 10. If so, it may be installed at the entrance/exit of hot water or water. For example, the cylindrical portion 1 may be provided at a drain port, a hot water supply port, or a hot water return port of a hot water storage tank.

As described above, the method for welding the cylindrical portion 1-3, the method for manufacturing a water heater, the method for manufacturing a compressor, and the welding devices 4A and 4B are not limited to the above embodiments, and various modifications and substitutions may be made. be able to. Various aspects of the present disclosure are described below as supplementary notes.

(Additional note 1)
A first cylindrical end of a first cylindrical part included in a first member and a second cylindrical part included in a second member and fitted in the first cylindrical part whose end surfaces are aligned with the first cylindrical end. melting two cylindrical ends to form a molten pool spanning the entire circumference of the first cylindrical end and the second cylindrical end;
a step of rotating at least one of the first cylindrical portion and the second cylindrical portion in the circumferential direction at least between the formation of the molten pool and the solidification thereof;
Equipped with
A method of welding the first cylindrical part and the second cylindrical part.
(Additional note 2)
A first cylindrical end of a first cylindrical part included in a first member and a second cylindrical part included in a second member and fitted in the first cylindrical part whose end surfaces are aligned with the first cylindrical end. a step of bringing an annular member into contact with the two cylindrical ends and covering the first cylindrical end and the second cylindrical end with the annular member;
By melting the annular member and melting the first cylindrical end and the second cylindrical end with the heat of melting the annular member, the first cylindrical end and the second cylindrical end are straddled. a step of forming a molten pool around the entire circumference;
a step of rotating at least one of the first cylindrical portion, the second cylindrical portion, and the annular member in the circumferential direction at least between the formation of the molten pool and the solidification thereof;
Equipped with
A method of welding the first cylindrical part and the second cylindrical part.
(Appendix 3)
In the step of forming the molten pool, a laser beam is annularly irradiated onto an annular surface formed by an end surface of the first cylindrical end and an end surface of the second cylindrical end. melting the second cylindrical end;
The method of welding the first cylindrical part and the second cylindrical part according to supplementary note 1 or 2.
(Additional note 4)
The laser beam is an annular parallel beam,
In the step of forming the molten pool, the laser beam is irradiated onto the annular surface from a direction in which a cylindrical axis of the first cylindrical part or the second cylindrical part extends.
The method of welding the first cylindrical part and the second cylindrical part according to appendix 3.
(Appendix 5)
The step of rotating at least one of the first cylindrical part and the second cylindrical part in the circumferential direction is performed at least after the start of irradiation with the laser beam.
The method of welding the first cylindrical part and the second cylindrical part according to appendix 3 or 4.
(Appendix 6)
The step of rotating at least one of the first cylindrical part and the second cylindrical part in the circumferential direction is performed before the start of irradiation with the laser beam.
The method of welding the first cylindrical part and the second cylindrical part according to appendix 3 or 4.
(Appendix 7)
In the step of rotating at least one of the first cylindrical part and the second cylindrical part in the circumferential direction, the first cylindrical part is rotated in one direction in the circumferential direction, and the second cylindrical part is rotated in the circumferential direction. rotate in the other direction,
The method for welding the first cylindrical part and the second cylindrical part according to any one of Supplementary Notes 1 to 6.
(Appendix 8)
In the step of rotating at least one of the first cylindrical part and the second cylindrical part in the circumferential direction, the first cylindrical part is rotated in one direction in the circumferential direction, and the second cylindrical part is rotated in the first cylindrical part. rotating in the one direction in the circumferential direction at a speed different from that of the cylindrical part;
The method for welding the first cylindrical part and the second cylindrical part according to any one of Supplementary Notes 1 to 6.
(Appendix 9)
At least one of the first cylindrical part and the second cylindrical part is a burring part surrounding a through hole formed in the plate-shaped part.
The method for welding the first cylindrical part and the second cylindrical part according to any one of Supplementary Notes 1 to 8.
(Appendix 10)
At least one of the first cylindrical part and the second cylindrical part is a circular tube,
The method for welding the first cylindrical part and the second cylindrical part according to any one of Supplementary Notes 1 to 8.
(Appendix 11)
Welding the first cylindrical part provided at the hot water or water entrance/exit of the hot water tank to the second cylindrical part of the piping using the welding method described in any one of Supplementary Notes 1 to 10.
How to manufacture a water heater.
(Appendix 12)
Welding the first cylindrical portion provided in the housing of the compressor to the second cylindrical portion of the piping using the welding method described in any one of Supplementary Notes 1 to 10.
Compressor manufacturing method.
(Appendix 13)
a first holding mechanism that holds a first cylindrical portion included in the first member;
A state in which the second cylindrical part provided in the second member and fitted into the first cylindrical part is aligned with the end surfaces of the first cylindrical end of the first cylindrical part and the second cylindrical end of the second cylindrical part. a second holding mechanism that holds the
melting the first cylindrical end of the first cylindrical part held by the first holding mechanism and the second cylindrical end of the second cylindrical part held by the second holding mechanism; a heating mechanism that forms a molten pool over the entire circumference spanning one cylindrical end and the second cylindrical end;
Equipped with
At least one of the first holding mechanism and the second holding mechanism is configured to hold the first cylindrical portion and the second cylindrical portion at least between the formation of the molten pool by the heating mechanism and the solidification of the molten pool. rotating at least one of the parts in the circumferential direction;
Welding equipment.
(Appendix 14)
The heating mechanism is a laser irradiator that irradiates laser light in an annular manner onto an annular surface formed by an end surface of the first cylindrical end and an end surface of the second cylindrical end.
The welding device according to appendix 13.
(Appendix 15)
The laser irradiator is arranged in a direction in which a cylindrical axis of the first cylindrical part or the second cylindrical part extends, and irradiates the annular surface with the laser light, which is annular parallel light.
The welding device according to appendix 14.
(Appendix 16)
At least one of the first holding mechanism and the second holding mechanism rotates at least one of the first cylindrical part and the second cylindrical part relative to the heating mechanism.
The welding device according to any one of appendices 13 to 15.

The present disclosure is capable of various embodiments and modifications without departing from the broad spirit and scope of the present disclosure. Further, the embodiments described above are for explaining the present disclosure, and do not limit the scope of the present disclosure. That is, the scope of the present disclosure is indicated by the claims rather than the embodiments. Various modifications made within the scope of the claims and the meaning of the disclosure equivalent thereto are considered to be within the scope of the present disclosure.

This application is based on Japanese Patent Application No. 2022-146737 filed on September 15, 2022. The entire specification, claims, and drawings of Japanese Patent Application No. 2022-146737 are incorporated herein by reference.

1-3 Cylindrical part, 4A, 4B welding device, 5 Welding part, 6 Molten pool, 7 Annular member, 10 Hot water storage tank, 11 Wall part, 12 Through hole, 13 Cylindrical end, 14 End part, 20 Nipple, 21 Main body Part, 23 Cylindrical end, 30 Hot water storage tank, 31 Joint, 33 Cylindrical end, 41 Holding mechanism, 42 Holding mechanism, 43 Laser irradiator, 44 Motor, 45 Controller, 60 Molten pool, 61 Reservoir, 71 Outer peripheral wall, 72 Inner peripheral wall, 411 Large cylinder, 412 Flange, 413 Cylindrical end, 414 Magnet, 415 Rib, 416 Spring, 417 Clamping part, 421 Cylindrical part, 422 Flange, 423 Magnet, 424 Attachment hole, 425 Through hole, 426 , 427 Pressing member, 428 Spring, 441 Bearing part, 442 Case, 443 Output shaft, A Cylindrical shaft, A1-A6, A10, A11, A20, A21, A30, A31 Arrow, AL Center axis, B Cylindrical axis, C Cylindrical Axis, IR irradiation area, L parallel light, P10, P11, P12, P20, P21, P22, P30, P31, P32 part.

Claims (16)

1. A first cylindrical end of a first cylindrical part included in a first member and a second cylindrical part included in a second member and fitted in the first cylindrical part whose end surfaces are aligned with the first cylindrical end. melting two cylindrical ends to form a molten pool spanning the entire circumference of the first cylindrical end and the second cylindrical end;
   a step of rotating at least one of the first cylindrical portion and the second cylindrical portion in the circumferential direction at least between the formation of the molten pool and the solidification thereof;
   Equipped with
   A method of welding the first cylindrical part and the second cylindrical part.
2. A first cylindrical end of a first cylindrical part included in a first member and a second cylindrical part included in a second member and fitted in the first cylindrical part whose end surfaces are aligned with the first cylindrical end. a step of bringing an annular member into contact with the two cylindrical ends and covering the first cylindrical end and the second cylindrical end with the annular member;
   By melting the annular member and melting the first cylindrical end and the second cylindrical end with the heat of melting the annular member, the first cylindrical end and the second cylindrical end are straddled. a step of forming a molten pool around the entire circumference;
   a step of rotating at least one of the first cylindrical portion, the second cylindrical portion, and the annular member in the circumferential direction at least between the formation of the molten pool and the solidification thereof;
   Equipped with
   A method of welding the first cylindrical part and the second cylindrical part.
3. In the step of forming the molten pool, a laser beam is annularly irradiated onto an annular surface formed by an end surface of the first cylindrical end and an end surface of the second cylindrical end. melting the second cylindrical end;
   The method of welding the first cylindrical part and the second cylindrical part according to claim 1 or 2.
4. The laser beam is an annular parallel beam,
   In the step of forming the molten pool, the laser beam is irradiated onto the annular surface from a direction in which a cylindrical axis of the first cylindrical part or the second cylindrical part extends.
   The method of welding the first cylindrical part and the second cylindrical part according to claim 3.
5. The step of rotating at least one of the first cylindrical part and the second cylindrical part in the circumferential direction is performed at least after the start of irradiation with the laser beam.
   The method of welding the first cylindrical part and the second cylindrical part according to claim 3 or 4.
6. The step of rotating at least one of the first cylindrical part and the second cylindrical part in the circumferential direction is performed before the start of irradiation with the laser beam.
   The method of welding the first cylindrical part and the second cylindrical part according to claim 3 or 4.
7. In the step of rotating at least one of the first cylindrical part and the second cylindrical part in the circumferential direction, the first cylindrical part is rotated in one direction in the circumferential direction, and the second cylindrical part is rotated in the circumferential direction. rotate in the other direction,
   The method of welding the first cylindrical part and the second cylindrical part according to any one of claims 1 to 6.
8. In the step of rotating at least one of the first cylindrical part and the second cylindrical part in the circumferential direction, the first cylindrical part is rotated in one direction in the circumferential direction, and the second cylindrical part is rotated in the first cylindrical part. rotating in the one direction in the circumferential direction at a speed different from that of the cylindrical part;
   The method of welding the first cylindrical part and the second cylindrical part according to any one of claims 1 to 6.
9. At least one of the first cylindrical part and the second cylindrical part is a burring part surrounding a through hole formed in the plate-shaped part.
   The method of welding the first cylindrical part and the second cylindrical part according to any one of claims 1 to 8.
10. At least one of the first cylindrical part and the second cylindrical part is a circular tube,
    The method of welding the first cylindrical part and the second cylindrical part according to any one of claims 1 to 8.
11. Using the welding method according to any one of claims 1 to 10, welding the first cylindrical part provided at the hot water or water entrance/exit of the hot water tank to the second cylindrical part included in the piping.
    How to manufacture a water heater.
12. Welding the first cylindrical portion provided in the housing of the compressor to the second cylindrical portion of the piping using the welding method according to any one of claims 1 to 10.
    Compressor manufacturing method.
13. a first holding mechanism that holds a first cylindrical portion included in the first member;
    A state in which the second cylindrical part provided in the second member and fitted into the first cylindrical part is aligned with the end surfaces of the first cylindrical end of the first cylindrical part and the second cylindrical end of the second cylindrical part. a second holding mechanism that holds the
    melting the first cylindrical end of the first cylindrical part held by the first holding mechanism and the second cylindrical end of the second cylindrical part held by the second holding mechanism; a heating mechanism that forms a molten pool over the entire circumference spanning one cylindrical end and the second cylindrical end;
    Equipped with
    At least one of the first holding mechanism and the second holding mechanism is configured to hold the first cylindrical portion and the second cylindrical portion at least between the formation of the molten pool by the heating mechanism and the solidification of the molten pool. rotating at least one of the parts in the circumferential direction;
    Welding equipment.
14. The heating mechanism is a laser irradiator that irradiates laser light in an annular manner onto an annular surface formed by an end surface of the first cylindrical end and an end surface of the second cylindrical end.
    The welding device according to claim 13.
15. The laser irradiator is arranged in a direction in which a cylindrical axis of the first cylindrical part or the second cylindrical part extends, and irradiates the annular surface with the laser light, which is annular parallel light.
    The welding device according to claim 14.
16. At least one of the first holding mechanism and the second holding mechanism rotates at least one of the first cylindrical part and the second cylindrical part relative to the heating mechanism.
    The welding device according to any one of claims 13 to 15.

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