JP4586855B2 - Manufacturing method of piping members - Google Patents

Description

  The present invention relates to a method for manufacturing a cylindrical piping member that is a welded portion with one end welded to another member.

  In recent years, a hot water supply system has emerged that collects heat from the atmosphere with a heat pump, stores hot water boiled with the heat in a tank, and supplies hot water from the tank (see, for example, Patent Document 1). A number of pipes through which water and hot water pass are connected to the tank, such as pipes for hot water supply, pipes for water supply, and pipes connected to a heat pump. For this pipe connection, a pipe member called a pipe seat is welded to the tank.

As shown in FIG. 10, a cylindrical portion 31 b that is bent toward the inside of the tank and a hole that is surrounded by the cylindrical portion 31 b are formed in the tube seat weld plane portion 31 a of the tank. The thin-walled cylindrical portion 262 of the pipe member (tube seat) 260 is fitted into the hole so as to contact the inner peripheral surface of the cylindrical portion 31b, and the end of the cylindrical portion 31b of the tank and the thin-walled cylindrical portion 262 of the pipe member 260 are fitted. Are welded all around. On the other hand, the pipe member 260 is formed with a flange 263 at a portion opposite to the thin-walled cylindrical portion 262 at the front end. The flange portion 263 is connected to a flange portion 181 of another pipe 180 through which water or hot water passes by a quick fastener 190 (a pipe joint member utilizing spring characteristics). The tip cylindrical portion 182 that protrudes in the axial direction from the inner peripheral portion of the flange portion 181 of the pipe 180 enters the internal space of the pipe member 260 and is in close contact with the inner peripheral surface 261 a of the pipe member 260 via the seal member 170. Thus, water and hot water flowing from the tank to the pipe 180 (or from the pipe 180 to the tank) via the pipe member 260 are prevented from leaking to the outside.
JP 2007-285655 A

  The pipe member 260 described above is often made of ferritic stainless steel equivalent to SUS444 having excellent stress corrosion cracking resistance, and the thickness of the thin-walled cylindrical portion 262 must be thinner than other portions. The outer diameter must also be highly accurate. For this reason, conventionally, the piping member 260 is manufactured by subjecting a thick-walled cylindrical material to machining (cutting or the like).

  However, in manufacturing by machining, the manufacturing time of the piping member 260 is long and the manufacturing cost is high.

  An object of the present invention is to manufacture a piping member earlier at a lower cost.

A method for manufacturing a piping member according to a first aspect of the present invention is a method for manufacturing a cylindrical piping member that is a welded portion with one end welded to another member, and includes a first step and a second step. . In the first step, the plate-like material is formed into a shape including the first part and the second part by press molding. The first part is a thick cylindrical part. The second part is a thin part that becomes a welded part, is adjacent to the first part, and intersects the first part. The second step is a step performed after the first step, and the second part is formed into a cylindrical shape by press molding, and a step is generated at the boundary between the first part and the second part. The first step includes a first drawing process and a plurality of second drawing processes . In the first drawing step , the plate-shaped material is formed so that the second part has a disk shape that closes one end of the cylindrical first part. In the second drawing step , the thickness of the disk-shaped second part is reduced. The second step includes a drilling process and a third drawing process . In the drilling step, the central part of the disk-shaped second part is extracted. In the third squeezing step , the annular second portion that has undergone the previous drilling step from the vicinity of the boundary with the first portion is formed into a cylindrical shape, and a step is generated at the boundary between the first portion and the second portion.

  In the first invention, a cylindrical thick first part and a thin second part adjacent to intersect with the first part are formed from a plate-like material by press molding in the first step, and thereafter In the second step, the second part is also formed into a cylindrical shape, and a step is generated at the boundary between the first part and the second part.

  In the second step, since the difference between the thicknesses of the first part and the second part is already generated in the first step, the step in the second step can be easily generated.

  In addition, since the second part in the first step intersects the cylindrical first part, even when performing a press that moves the press mold along the axial direction of the cylindrical first part. It is easy to reduce the thickness of the second part.

  As described above, in the first invention, the shape before performing the second step (the shape formed in the first step) is easy to thin the second part, and the second part is formed in the second step. Since the piping member is manufactured by forming a cylindrical shape and creating a step at the boundary between the first part and the second part, the manufacturing of the piping member by press molding can be performed in a short time with a high yield. And since a piping member can be manufactured by press molding, the manufacturing time is shortened compared with the piping member by the conventional machining.

In the first invention, the first drawing step converts the plate-like material into a glass-like shape including a cylindrical first part and a disk-like second part that closes one end of the first part. The thickness of the second part is reduced by the subsequent second drawing step . For this reason, in the second drawing step , the mold can come into contact with both surfaces of the disk-shaped second part to apply a force in the thickness direction of the second part, and the second part is formed into a cylindrical shape from the beginning. Then, compared with the method of reducing the thickness, the second portion can be easily and quickly reduced in thickness.

In the first invention, the central part of the second part is first extracted, and then the annular second part is formed into a cylindrical shape. Therefore, after the disk-shaped second part is formed into a cylindrical shape, Compared to a method of cutting unnecessary portions, a thin cylindrical weld can be formed quickly and accurately.

The manufacturing method of the piping member according to the second invention is the manufacturing method of the first invention , further comprising a third step. The third step is a step performed after the third squeezing process of the second step, and a force for compressing in the axial direction is applied to the cylindrical second part so that the second part is the final part of the welded part. Mold into shape.

In the second invention , since the third step for applying the axial compressive force to the cylindrical second part is further added, the second part can be accurately finished to the final shape of the welded part.

According to the first invention, the piping member can be manufactured at a lower cost and faster than the piping member by conventional machining. Further, the thinning of the second part can be performed easily and quickly. Moreover, a thin-walled cylindrical weld can be formed quickly and accurately.

According to the second invention , the second part can be accurately finished to the final shape of the welded part.

<Configuration of hot water storage type water heater>
FIG. 1 is an external perspective view of a hot water storage type hot water heater using a piping member (pipe seat) according to the present embodiment, and FIG. 2 is a configuration diagram of the hot water storage type hot water heater. In FIG. 1, a hot water storage type water heater 1 includes a heat pump unit 2 and a hot water storage device 3, and a vapor compression refrigeration circuit is accommodated in the casing of the heat pump unit 2. The hot water storage tank 31 is accommodated.

  In FIG. 2, the heat pump unit 2 includes a muffler 21 a, a compressor 21, a refrigerant pipe 22 a in the water heat exchanger 22, an expansion valve 23 as a decompression unit, and an air heat exchanger 24 connected in a ring shape by a refrigerant pipe 25. The vapor compression refrigeration circuit 20 is provided.

  The refrigeration circuit 20 is provided with a liquid gas heat exchanger 26 for heat exchange between the high-pressure and high-temperature refrigerant coming out of the water heat exchanger 22 and the low-pressure and low-temperature refrigerant coming out of the air heat exchanger 24. Has been. Specifically, heat exchange is performed between the refrigerant passage connecting the water heat exchanger 22 and the expansion valve 23 and the refrigerant passage connecting the air heat exchanger 24 and the compressor 21.

  The hot water storage device 3 includes a water circulation circuit 30 in which a hot water storage tank 31, a water pipe 22 b in the water heat exchanger 22, and a water circulation pump 32 are annularly connected by a water circulation pipe 35. The control device 4 controls the operation of the heat pump unit 2 and the hot water storage device 3.

<Configuration of hot water storage device including hot water storage tank>
FIG. 3 is a circuit diagram of piping for connecting the hot water storage device 3 of the hot water storage type hot water supply device 1 and a load. In addition, the load described here refers to hot water supply and a bath. The hot water supply pipe 71 communicates the head of the hot water storage tank 31 with the hot water supply mixing valve 73. The hot water supply pipe 71 has hot water supply branch pipes 71 a and 71 b, the hot water supply branch pipe 71 a connects the hot water supply pipe 71 and the hot water beam mixing valve 74, and the hot water supply branch pipe 71 b includes the hot water supply pipe 71 and the relief valve 75. Have contacted.

  The water supply pipe 72 connects the water supply source and the hot water supply mixing valve 73. The water supply pipe 72 has water supply branch pipes 72a and 72b. The water supply branch pipe 72 a connects the water supply pipe 72 and the hot water mixing valve 74, and the water supply branch pipe 72 b connects the water supply pipe 72 and the bottom of the hot water storage tank 31. A pressure reducing check valve 76 is connected upstream of the water supply branch pipe 72a and the water supply branch pipe 72b. A water temperature sensor 41 is provided at a position away from the hot water storage tank 31 in the water supply branch pipe 72b. The water temperature sensor 41 is considered so as not to be affected by the temperature from the hot water storage tank 31.

  The hot water circulation pipe 77 communicates the head of the hot water storage tank 31 and the bottom of the hot water storage tank 31, and an additional heat exchanger 78 and a circulation pump 79 are connected on the way.

  The second hot water supply pipe 81 connects the hot water supply mixing valve 73 and the hot water supply port 82, and a hot water supply water amount sensor 42a is disposed on the way. The third hot water supply pipe 83 communicates the hot water mixing valve 74 and the bath water circulation pipe 91, and a composite water valve 84 is disposed on the way. The composite water valve 84 includes a hot water solenoid valve 84a, a drain valve 84b, and a hot water volume sensor 42b.

  The bath water circulation pipe 91 exits from the bathtub 92 and returns to the bathtub 92, and a bath water circulation pump 93 is connected on the way. It should be noted that heat is exchanged between the bath water circulation pipe 91 and the hot water circulation pipe 77 in the memory heat exchanger 78.

  On the side wall of the hot water storage tank 31, temperature sensors 44 a to 44 e are provided as remaining hot water amount detection means at regular intervals from the head to the bottom. By detecting the hot water temperature at each height position of the hot water storage tank 31 with the temperature sensors 44a to 44e, the temperature of the hot water and the remaining hot water amount are calculated. In addition, the hot water storage tank 31 is covered with a heat insulating material on the entire side wall, the head, and the bottom.

<Configuration of piping member welded and fixed to hot water storage tank>
As described above, the hot water storage tank 31 is connected with a number of pipes through which water and hot water pass, such as the hot water supply pipe 71, the water supply pipe 72, the hot water circulation pipe 77, and the water circulation pipe 35. In order to connect each of these pipes (hereinafter referred to as the pipe 180) and the hot water storage tank 31, a pipe member 60 called a pipe seat is used. As shown in FIG. 5, the piping member 60 mainly includes a cylindrical portion 61, a thin tip cylindrical portion 62 having a smaller outer diameter than the cylindrical portion 61, and a thin tip cylindrical portion 62 sandwiching the cylindrical portion 61. It consists of the collar part 63 arrange | positioned on the opposite side. The collar portion 63 is an annular portion that extends radially outward from one end of the cylindrical portion 61.

  As shown in FIGS. 4A, 4 </ b> B, and 5, the piping member 60 is inserted into a hole formed in the flat portion 31 a of the hot water storage tank 31 and welded to the hot water storage tank 31, for example. Specifically, a hole and a cylindrical portion 31 b (see FIG. 5) that is bent from the periphery of the hole toward the inside of the hot water storage tank 31 are formed in the flat surface portion 31 a of the hot water storage tank 31. The thin-walled cylindrical portion 62 of the pipe member 60 is inserted into the hole of the hot water storage tank 31. The end of the thin cylindrical portion 62 of the pipe member 60 and the tip of the cylindrical portion 31b of the hot water storage tank 31 are welded all around. Thereby, the piping member 60 is fixed to the hot water storage tank 31.

  For insertion and all-around welding, the thin-walled cylindrical portion 62 of the pipe member 60 needs to be manufactured with a particularly accurate outer dimension, and the outer peripheral surface and the cylindrical portion of the thin-walled cylindrical portion 62 of the pipe member 60 are used. A step 66 that presses against the flat portion 31 a around the hole of the hot water storage tank 31 needs to be formed at the boundary with the outer peripheral surface of 61.

  On the other hand, as shown in FIG. 5, the flange portion 63 of the piping member 60 contacts the flange portion 181 of the pipe 180 connected to the hot water storage tank 31 and is connected to the flange portion 63 by the quick fastener 190 so as not to be separated. The quick fastener 190 is a metal pipe joint member having the shape shown in FIGS. 6A and 6B, and both members to be connected by the gripping portions 191 and 192 positioned on the left and right of the long hole 190 a using the spring characteristics. Grip the cylindrical body. Specifically, the grip part 191 that grips the cylindrical part 61 of the pipe member 60 by fitting the collar part 63 of the pipe member 60 and the collar part 181 of the pipe 180 in contact with each other into the elongated hole 190 a of the quick fastener 190. And the grip 192 that grips the cylindrical body of the pipe 180 prevent the pipe member 60 and the pipe 180 from separating in the axial direction (see FIG. 5).

  Since the quick fastener 190 serves as a pipe joint, the flange 63 of the pipe member 60 needs to have a predetermined thickness L3 (length in the axial direction). Only a predetermined dimension needs to be secured in the radial dimension of the surface on which 191 is caught.

  In order to shorten the manufacturing time that has been required in the past by manufacturing the piping member by cutting from a thick material while satisfying the requirements required for the piping member 60 as described above, here, the piping The member 60 is manufactured by a plurality of press molding processes, and the shape of the piping member 60 is devised.

  The piping member 60 integrally formed from the plate-like material 50 (see FIGS. 7 and 8) by a plurality of press forming processes has a cross-sectional shape in which the flange portion 63 includes a step 67 (see FIG. 5). The thickness L3 of the flange 63 is larger than the thickness t1 of the plate material 50. Here, the thickness t1 = 1.5 mm and the thickness L3 = 2.8 mm. Further, the step 67 of the flange portion 63 includes a curved portion that bends to about 90 °, and a dimension r4 (see FIG. 5) that is a radius of curvature R of the surface of the curved portion is formed to be 0.5 mm or less. Yes.

  Further, a step 66 is formed at the boundary between the thick-walled (thickness t1) cylindrical portion 61 and the thin-walled (thickness t2) distal thin-walled cylindrical portion 62, and the outer diameter of the thin-walled cylindrical portion 62 and the flat surface portion 31a of the hot water storage tank 31 are formed. The piping member 60 is press-molded so that the inner diameter of each of the holes coincides, and the tip of the thin-walled cylindrical portion 62 and the tip of the cylindrical portion 31b of the hot water storage tank 31 are at the same height.

  In addition, each dimension shown in FIG. 5 is D1 = 20mm or 26mm, D2 = 22mm or 27mm, L1 = 6.5-10.0mm, L2 = 1.5-4.0mm, L3 = 2.6-3. 0 mm, L4 = 1.0 to 4.3 mm, t1 = 0.5 to 2.0 mm, t2 = 0.5 to 1.8 mm (where t2 <t1), r1> 1.0 mm, r2 <0.5 mm R3 <0.5 mm and r4 <0.5 mm. Here, D1 = 20 mm, D2 = 22 mm, L1 = 9.0 mm, L2 = 2.0 mm, L3 = 2.8 mm, L4 = 4.2 mm, t1 = 1.5 mm, t2 = 1.0 mm, r1> 1 A piping member 60 of 0.0 mm, r2 <0.5 mm, r3 <0.5 mm, r4 <0.5 mm is manufactured.

<Manufacturing method of piping member>
In the piping member 60, the lower part in FIG. 5 is a tip thin-walled cylindrical part 62 welded to the hot water storage tank 31, and the upper part in FIG. 5 is a flange part 63 that is a connection part to the pipe 181. It can be said that there is a step 66 between the cylindrical portion 61 and the piping member 60 having a step 67 between the flange 63 and the cylindrical portion 61. This piping member 60 is manufactured by 10 processes (S1-S10) including many press molding processes, as shown in FIGS. However, since one process is completed within several seconds and flows one after another, the total time required for manufacturing the piping member 60 is considerably shorter than that of a manufacturing method using conventional machining.

  Here, as shown in the left end portion of FIG. 7 and FIG. 8, a press forming process or the like is sequentially performed on the substantially circular plate-shaped material 50. The plate material 50 is a ferritic stainless steel having a chromium (Cr) content of 17 to 20%, a molybdenum (Mo) content of 1.7 to 2.5%, and a carbon (C) content of 0.03 or less. It is. By using a plate-like material 50 having a thickness of 2 mm or less, even a material having such a composition can be press-molded, and the plate-like material 50 is hardly damaged by the press-molding. Here, a plate-like material 50 having a plate thickness of 1.5 mm is used.

  Each step (S1 to S10) will be described in detail later. First, the entire manufacturing method will be described.

  The manufacturing method of the piping member 60 includes a plate-shaped material 50 formed by press forming a thin cylindrical first portion (51a... 51h) and a thin cylindrical portion 62 adjacent to the first thin cylindrical portion 62 adjacent thereto. It is said that it is a manufacturing method in which a shape including two parts (52a... 52h) is formed and a step (56h) is formed at the boundary between the first part (51h) and the second part (52h). be able to.

  Moreover, when the manufacturing method of the piping member 60 pays attention to the part used as the level | step difference 66, three processes, the process group before drilling (S1-S6), the drilling process S7, and the process group after drilling (S8-S10). It can be divided into steps. In the process group (S1 to S6) before drilling, the plate-shaped material 50 is formed into a cylindrical thick first part (51a... 51f) and a tip thin cylindrical part 62 adjacent thereto by press molding. It shape | molds in the shape containing 2nd thin part (52f). The first part (51a... 51f) and the second part (52a... 52f) are in a relationship between a cylindrical part and a disk part that closes one end of the cylindrical part, and are orthogonal to each other. . The thickness of the first part (51f) and the second part (52f) after the sixth drawing step S6 is t1 and t2 (t2 <t1), and the second part (52f) has a plurality of diaphragms. The plate thickness t2 is reduced through the process (press molding process). In the process group (S8 to S10) after drilling, the second part (52g), which is formed in a ring shape by cutting out the central part, is formed into a cylindrical shape by the first finishing drawing process S8, and the first part (51h) And a step (56h) is produced at the boundary between the second part (52h). Further, in the second finishing drawing step S <b> 9, an axial compression force is applied to the cylindrical second part (52 h), and the second part is formed into the final shape of the thin-walled cylindrical part 62 at the tip.

  In addition, the process group (S1-S6) before drilling is the 1st aperture_diaphragm | restriction which shape | molds the plate-shaped raw material 50 so that the 2nd part (52a) may become the disk shape which plugs up the end of the cylindrical 1st part (51a). This can be divided into two steps: a process S1 and a thinning process group (S2 to S6) for reducing the thickness of the second part (52a).

  In addition, the process group (S1 to S6) before drilling focuses on the forming of the collar part 63, and includes the first drawing process S1 before the collar part molding and the subsequent collar part molding process group (S2). It can be divided into two steps. In the first drawing step S1, the plate-like material 50 is formed into an initial shape including a cylindrical first portion (51a) by press molding. And in the collar part forming process group after the second drawing process S2, the end part of the first part (51a) of the forming intermediate material having the initial shape is curved and extended radially outward, and the first part. (51a) is a first part (51b...) And a third part (53b...), And is formed into the shape of the cylindrical part 61 and the collar part 63.

  Moreover, the process group (S1-S6) before drilling pays attention to the part which becomes the level | step difference 67, the preparation process group (S1-S3) before detailed shape shaping | molding of the collar part 63, and the detailed shape shaping | molding of the collar part 63. It can be divided into two steps, the process group (S4 to S6). In the preparation process group (S1 to S3) before forming the detailed shape of the flange part 63, the plate-shaped material 50 is subjected to a plurality of drawing processes (press forming process), and the first part (51c) and the flange part that become the cylindrical part 61 Molded into a molding intermediate material including the third part (53 c) to be 63. In the detailed shape forming step group (S4 to S6) of the flange portion 63, a step (57e) is formed in the third portion (53d... 53f) of the forming intermediate material by a plurality of drawing steps. The step (57e) is a step having steps both in the axial direction and in the radial direction.

  Further, when paying attention to the portion that becomes the step 67, the drilling step S7 and the process group after drilling (S8 to S10) are the finishing process group of the step 67 (S7 to S9) and the outer diameter removing process S10 that completes the step 67. Can be divided into two steps. In the finishing step group (S7 to S9) of the step 67, the third part (53f) of the molded intermediate material on which the step (57e) is formed is finished into a shape including the final step shape by a plurality of steps. In the outer diameter removing step S10, the radially outer portion (55j) of the third part (53i) of the molded intermediate material having the shape including the final step shape is cut to form the third part (53j) of the molded intermediate material. And As a result, the third portion (53j) is completed as the flange portion 63 having a predetermined outer dimension.

  Then, each process (S1-S10) is explained in full detail next.

[S1: First drawing step]
As shown in FIGS. 7 and 8, first, a first drawing step S <b> 1 that is the first press forming step is performed on a circular plate-shaped material 50 whose periphery is cut except for a part. Here, the plate-like material 50 is sandwiched between upper and lower molds so as to have a glass-like shape composed of a cylindrical first part (51a) and a disk-like second part (52a). Is press-molded. Thereby, the plate-shaped raw material 50 is shape | molded by the initial shape whose cross section as shown in FIG. 8 is concave (glass shape).

[S2: Second drawing step]
Next, by a plurality of press molding steps (steps S2 to S6), the first portion (51a) is curved in the vicinity of the end opposite to the second portion (52a) and extended radially outward. The thickness of the second part (52a) is reduced.

  First, in the second squeezing step S2, the first part (51a) is bent so that the upper part of the first part (51a) faces obliquely upward, and the first part (51a) is changed to the first part (51b) and the first part (51b). 3 parts (53b). Further, a compressive force is applied from the mold in the thickness direction (vertical direction) to the second portion (52a), and the second portion (52a) is slightly thinner than the second portion (52b). And

[S3: Third drawing step]
In the third squeezing step S3, the third part (53b) is press-molded so as to be closer to the horizontal direction, and the second part (52b) is a second part (52c) slightly thinner than that. .

[S4: Fourth drawing step]
In the fourth squeezing step S4, approximately half of the distal end side of the third part (53c) is bent to the opposite side so far so that the third part (53c) faces upward in the middle. A step is generated in the third part (53c) that has undergone the press molding.

  Also in the fourth drawing step S4, the second part (52c) is a second part (52d) having a slightly smaller plate thickness.

[S5: Fifth drawing step]
In the fifth squeezing step S5, press molding is further performed to bend the tip outward so that the tip approaches the horizontal direction of the tip half of the third half (53d) facing upward. . Accordingly, a step (57e) having a step in the axial direction (vertical direction) and the radial direction (horizontal direction) is generated in the third part (53e) that has undergone the fifth drawing step S5.

  Also in the fifth drawing step S5, the second part (52d) is a second part (52e) having a slightly smaller plate thickness.

[S6: Sixth drawing step]
In the sixth drawing step S6, the third part (53e) is press-molded so that the angle of the curved part of the step (57e) becomes smaller. Thereby, the third part (53e) becomes the third part (53f) closer to the final shape.

  Also in the sixth drawing step S6, the second part (52e) is a second part (52f) having a slightly smaller plate thickness. The thickness of the second part (52f) of the intermediate formed material that has undergone the sixth drawing step S6 is t2. On the other hand, the thickness of the first part (51f) of the intermediate molding material is t1.

[S7: Drilling step]
In the drilling step S7 performed after the sixth squeezing step S6, the central portion of the second part (52f) which is the bottom of the glass-like intermediate molding material is cut off. Specifically, a round hole having a diameter slightly smaller than the inner diameter of the first part (51f) is formed in the second part (52f). Thereby, the second part (52f) becomes an annular second part (52g) in which a circular central part (54g) is cut out.

  Further, the third part (53f) becomes the third part (53g) closer to the final shape.

[S8: First finishing drawing step]
In the first finish drawing step S8, press molding is performed so that the annular second portion (52g) faces downward. Thereby, the tip of the annular second part (52g) extends in the vertical direction from the vicinity of the boundary with the first part (51g). Thereby, the annular second part (52g) becomes the cylindrical second part (52h). Accordingly, a step (56h) is generated at the boundary between the second part (52h) and the first part (51h).

  Further, the third part (53g) becomes the third part (53h) closer to the final shape.

[S9: Second finishing drawing step]
In the second finishing drawing step S9, the outer diameter of the thin-walled cylindrical portion 62 and the inner diameter of the hole of the flat portion 31a of the hot water storage tank 31 are matched, and the distal end of the thin-walled cylindrical portion 62 and the cylindrical portion of the hot water storage tank 31 are matched. This is a process performed for the purpose of bringing the tip of 31b to the same height position.

  In the second finishing drawing step S9, a force compressing in the axial direction is applied to the cylindrical second part (52h), and the second part (52h) is the same as the final shape of the thin-walled cylindrical part 62 at the tip. It shape | molds in the shape 2nd part (52i).

  Further, the third part (53h) becomes the third part (53i) having the same shape as the final shape except for the outer diameter. In the third part (53i), the curved part is bent at about 90 °, and the dimension r4 (see FIG. 5), which is the curvature radius R of the surface of the curved part, is 0.5 mm or less.

[S10: Outer diameter removing step]
In the outer diameter removing step S <b> 10, the radially outer portion (55 j) of the third portion (53 i) of the molded intermediate material is cut, and the third portion (53 i) is a third portion ( 53j). The cutting in this step S10 is performed on the outer side in the radial direction from the step (57j) which is the final step shape of the step 67 of the flange portion 63.

<Characteristics of manufacturing method of piping member>
(1)
Normally, when a member consisting of a cylindrical part and a collar part is manufactured using press molding, the material is press-molded so as to have a final shape including the collar part or a shape close to the final shape. In the case of a simple manufacturing method, if the material is hard or thick, it is difficult to perform press molding well. Even if the equipment for press molding is enlarged, the rate of damage to the material subjected to press molding increases. For this reason, conventionally, as shown in FIG. 10, a machine that cuts a thick cylindrical material having a thickness of 3.5 mm to reduce the thickness of the thin cylindrical portion 260e to 1.0 mm or less. Although the piping member 260 is manufactured by a manufacturing method by processing, the manufacturing (processing) takes a long time and cost.

  On the other hand, in the manufacturing method of the piping member 60 described above, first, the first drawing step S1 is press-molded so as to have an initial shape including the cylindrical first portion (51a), and then the flange portion forming step group. In (S2), press molding is performed to curve the vicinity of the end of the cylindrical first part (51a), and the first part (51a) is the first part corresponding to the cylindrical part 61 and the flange part 63 ( 51a ... 51j) and the third part (53b ... 53j). For this reason, although a plurality of press forming steps are required, damage to the plate-like material 50 and the intermediate formed material due to press forming is suppressed in both the first drawing step S1 and the buttocks forming step group (S2). Thus, the production of the piping member 60 with a good yield can be realized. Moreover, since the manufacturing of the piping member 60 by press molding is realizable by taking such a manufacturing method, the manufacturing time is shortened compared with the manufacturing method of the piping member by the conventional machining.

  As described above, the piping member 60 can be manufactured more quickly and cheaply by the above-described manufacturing method.

(2)
Further, in the above-described manufacturing method, the cylindrical first part (51a) is changed into the first part (51b ... 51j) and the third part (53b ... 53j) by a number of press molding steps (S2 to S2). Thus, since the cylindrical portion 61 and the flange portion 63 are molded, even if the flange portion 63 includes a complicated step shape, the flange portion 63 can be accurately molded while avoiding damage.

(3)
In the manufacturing method of the piping member 60 described above, in the first squeezing step S1, the plate-like material 50 is press-molded so as to have a concave cross section, that is, a glass-like initial shape, and then a flange forming step group ( The piping member 60 is manufactured by extending the third portion (53b) radially outward in S2) and cutting the central portion (54g) of the second portion (52f) in the drilling step S7. Thus, since the initial shape formed in the first drawing step S1 is a glass shape including the disk-like second part (52a), press forming from the plate-like material 50 in the first drawing step S1 is impossible. This is performed well, and the plate-like material 50 is hardly damaged, resulting in a high yield rate.

(4)
In the above-described piping member 60, the thickness (L3) of the flange 63 larger than the thickness (t1) of the plate-like material 50 is secured by adopting the flange 63 having a cross-sectional shape including a step. . For this reason, the collar part 63 of desired thickness (L3) can be obtained by press-molding the plate-shaped raw material 50. FIG.

  If the cross-sectional shape of the collar portion 263 is a simple rectangle as in the prior art (see FIG. 10), the plate thickness of the plate-shaped material must be equal to ensure the thickness, It becomes impossible, or even if possible, it is unavoidable to increase the cost of the press equipment and lengthen the press time. However, if it is the piping member 60 containing the above-mentioned level | step difference 67, the comparatively thin plate-shaped raw material 50 can be press-molded, and the collar part 63 of desired thickness (L3) can be obtained.

  Thus, if it is the piping member 60, the cylindrical part 61 and the collar part 63 of desired thickness (L3) can be integrally molded by press molding. For this reason, the manufacturing time is shortened compared with the piping member by the conventional machining.

(5)
In the manufacturing method of the piping member 60 described above, the third part (53b, 53c) is generated in the preparation process group (S1 to S3) before forming the detailed shape of the flange part 63, and the detailed shape forming process group of the flange part 63 is produced. In (S4 to S6), a step is formed in the third part (53c), and the third step (53d... 53f) having the step is formed by the drilling step S7 and the group of steps after drilling (S8 to S10). Finished in shape including shape. As a result, the thickness (t1) of the plate-like material 50 is suppressed to 2 mm or less (here, 1.5 mm), and the desired thickness (L3) of the collar portion 63 is ensured while reducing the cost of the press molding equipment. Have been able to.

(6)
In the manufacturing method of the piping member 60 described above, many press moldings are performed so that the curvature radius r4 of the surface of the curved portion that bends to about 90 ° is 0.5 mm or less. For this reason, it becomes possible to secure a large length along the radial direction of the surface 63a of the portion of the flange portion 63 that extends from the upper end of the cylindrical portion 61 by the length L2 outward in the radial direction. Here, the length along the radial direction of the surface 63 a is secured to 1 mm or more which is the thickness of the quick fastener 190. Therefore, if the quick fastener 190 is hung on the collar part 63 in order to connect with the piping 180, the quick fastener 190 will not come off arbitrarily after that.

(7)
In the manufacturing method of the piping member 60 described above, the outer peripheral edge of the flange 63 is cut because the radially outer portion (55j), which is the portion in the vicinity of the outer peripheral edge of the third portion (53j), is cut in the outer diameter removing step S10. The accuracy of the shape is high.

(8)
In the manufacturing method of the piping member 60 described above, in the outer diameter removing step S10, cutting is performed on the radially outer side than the step (57j) in view of the fact that the cutting thickness increases when cutting at the step (57j). . Thereby, it is only necessary to cut in the outer diameter removing step S10 by the thickness (t1) of the plate-like material 50, and an increase in the size of the cutting device and an increase in equipment costs are suppressed.

(9)
In the manufacturing method of the piping member 60 described above, the first thin-walled cylindrical portion 262 (see FIG. 10) to be a welded portion is not formed by machining as in the prior art, but the first portion (51h) in the first finishing drawing step S8. ) And the second part (52h), the piping member 60 is manufactured by press molding so that a step (56h) is generated. For this reason, compared with the piping member by the conventional machining, the piping member 60 can be manufactured earlier at a lower cost.

(10)
In the manufacturing method of the piping member 60 described above, the cylindrical thick first portion (51f) and the thin second portion (52f) adjacent to intersect with the first portion (51f) are drilled. Formed from the plate-shaped material 50 by press molding of the previous process group (S1 to S6), and in the subsequent drilling process S7 and the process group after drilling (S8 to S10), the second part (52g) is molded into a cylindrical shape. In addition, a step (56h) is generated at the boundary between the first part (51h) and the second part (52h).

  And in the process group (S1 to S6) before drilling, since the thickness (t1) of the first part (51f) and the thickness (t2) of the second part (52f) are already generated, A step (56h) can be easily generated in the process group (S8 to S10).

  Moreover, since the 2nd part (52a ... 52e) in the process group (S1-S6) before drilling is orthogonal to the cylindrical 1st part (51a ... 51e), it is cylindrical. In the case where press molding is performed to move the mold along the axial direction of the first part (51a... 51e), it is easy to reduce the thickness of the second part (52a... 52e). Yes.

  Thus, here, the shape (glass shape) of the intermediate molding material in the process group (S1 to S6) before drilling is easy to thin the second part (52a ... 52e), and By forming the second part (52g) into a cylindrical shape in the process group (S8 to S10) after drilling, a step (56h) is generated at the boundary between the first part (51h) and the second part (52h). Manufactures piping members. For this reason, manufacture of the piping member 60 by press molding can be performed in a short time with a good yield. And since the piping member 60 can be manufactured by press molding, the manufacturing time is shortened compared with the piping member by the conventional machining.

(11)
In the manufacturing method of the piping member 60 described above, the plate-shaped material 50 is covered with the cylindrical first part (51a) and the disk-shaped second part that closes one end of the first part (51a) by the first drawing step S1. (52a) is formed into a glass-like shape, and the thickness of the second part (52a) is reduced by the subsequent thinning process group (S2 to S6). For this reason, in the thinning process group (S2 to S6), the mold comes into contact with the upper and lower surfaces of the disk-shaped second part (52a... 52e), and the plate thickness of the second part (52a... 52e). A force can be applied in the direction. For this reason, compared with the method of forming the second part into a cylindrical shape from the beginning and then reducing the thickness, the second part (52a... 52e) can be easily and quickly made thinner.

(12)
In the manufacturing method of the piping member 60 described above, the center part of the second part (52f) is extracted in the drilling step S7, and then the annular second part (52g) is formed into a cylindrical shape. Compared with the method of cutting the unnecessary portion after forming the second portion into a cylindrical shape, the thin-walled cylindrical tip 62 can be formed quickly and accurately.

  In addition, after the first finishing drawing step S8 for forming the annular second part (52g) into a cylindrical shape, the second finishing is performed by applying an axial compressive force to the cylindrical second part (52h). Since the drawing step S9 is performed, the second part (52h) can be accurately finished to the final shape of the thin-walled cylindrical part 62 at the tip.

The external appearance perspective view of the hot water storage type water heater which concerns on this embodiment. The schematic block diagram of a hot water storage type water heater. The circuit diagram of the piping which connects the hot water storage apparatus of a hot water storage type water heater, a hot water supply port, and a bathtub. The top view of a hot water storage tank. 4A is a cross-sectional view taken along the arrow IV-IV in FIG. 4A. The longitudinal cross-sectional view of a piping member. The front view of a quick fastener. FIG. 6B is a cross-sectional view taken along the line VI-VI in FIG. 6A. The top view of the plate-shaped raw material before and after a 1st drawing process. Sectional drawing of the plate-shaped raw material before and after the 1st-4th drawing process (equivalent to the IIIV-IIIV arrow sectional drawing of FIG. 7). Sectional drawing of the plate-shaped raw material before and after a 5th, 6th drawing process, a drilling process, the 1st, 2nd drawing process, and an outer diameter extraction process. The longitudinal cross-sectional view of the conventional piping member.

31 Hot water storage tank (other parts)
50 Plate-like material 51a ... 51j 1st part 52a ... 52j 2nd part 56h Level difference 60 Piping member 61 Cylindrical part 62 Tip thin cylindrical part (welded part)
S1 first drawing process (first step; first press molding process)
S2 Second drawing process (first step; second press molding process)
S3 Third drawing step (first step; second press molding step)
S4 Fourth drawing process (first step; second press molding process)
S5 Fifth drawing process (first step; second press molding process)
S6 Sixth drawing step (first step; second press molding step)
S7 Drilling process (second step)
S8 First finish drawing process (second step; third press molding process)
S9 Second finishing drawing process (third step)

Claims (2)

A method of manufacturing a cylindrical piping member (60), which is a welded portion (62) whose one end is welded to another member (31),
The plate-like material (50) is drawn to form a cylindrical thick first part (51f) and a thin second part adjacent to the first part and intersecting the first part to become the welded part. A first step (S1 to S6), which is formed into a shape including (52f),
After the first step, the second part is formed into a cylindrical shape by press molding, and a step (56h) is generated at the boundary between the first part and the second part, a second step (S8);
Equipped with a,
The first step includes
A first squeezing step (S1) for forming the plate-like material so that the second part has a disk shape that closes one end of the cylindrical first part;
It said reducing the thickness of the second part of the disk-shaped, seen including a plurality of second drawing step (S2 to S6),
The second step includes
A drilling step (S7) for extracting a central portion (54g) of the disc-shaped second portion (52f);
The annular second part (52g) that has undergone the previous drilling process from the vicinity of the boundary with the first part is formed into a cylindrical shape, and the step ( 56h), the third squeezing step (S8),
The manufacturing method of the piping member containing this . After the third squeezing step of the second step, an axial compression force is applied to the cylindrical second part (52h), and the second part is formed into the final shape of the welded part. 3rd step (S9)
The method for manufacturing a piping member according to claim 1 , further comprising:

Images