JP2021006349A - Method of manufacturing heat exchanger - Google Patents

Abstract

To provide a method of manufacturing a heat exchanger capable of preferably joining aluminum alloys of different kinds of materials.SOLUTION: A method of manufacturing a heat exchanger includes a permanent joining step of inserting only an agitation pin F2 of a rotary tool F into an outer peripheral surface 11f of an extruded porous pipe 2, and turning a butted portion J1 round about the outer peripheral surface 11f of the extruded porous pipe 2 with a predetermined depth along a set moving route L1 set on the extruded porous pipe 2 side than the butted portion J1 to friction-stir the butted portion J1, while an outer peripheral surface of the agitation pin F2 is slightly contacted with a stepped inclined surface 23b of a cover body 3 and a second aluminum alloy is flowed into a clearance. In the permanent joining step, after only the rotating agitation pin F2 is inserted into a start position SP1 set further on the extruded porous pipe 2 side than the set moving route L1, the agitation pin F2 is gradually pressed in the predetermined depth while moving a rotation center axis Z of the rotary tool F to a position where the same overlapped with the set moving route L1.SELECTED DRAWING: Figure 4

Description

The present invention relates to a method for manufacturing a heat exchanger.

For example, Patent Document 1 describes a method for manufacturing a heat exchanger in which an extruded perforated tube in which a plurality of holes are arranged side by side and a sealing body for sealing the openings of the extruded perforated tube are joined by frictional stirring. It is disclosed. FIG. 8 is a cross-sectional view showing a method of manufacturing a conventional heat exchanger.

In the conventional method for manufacturing a heat exchanger, an extruded perforated tube 101 made of an aluminum alloy having a plurality of fins 110 and a stepped portion 103 formed on the outer periphery of the lid 102 are butted to form a butt portion J10. , The butt portion J10 is subjected to friction stir welding using the rotary tool G. The step portion 103 is composed of a step bottom surface 103a and a step side surface 103b. The butt portion J10 is configured by abutting the end surface 101a of the extruded perforated pipe 101 and the step bottom surface 103a of the lid 102. The rotation tool G includes a shoulder portion G1 and a stirring pin G2 hanging from the shoulder portion G1. In the friction stir welding step, the rotation center axis Z of the rotated stirring pin G2 is superposed on the butt portion J10 and relatively moved.

Japanese Unexamined Patent Publication No. 2016-74016

Here, a relatively simple shape such as the extruded perforated pipe 101 is formed of a wrought material of a 1000 series aluminum alloy, and the lid 102 is formed of, for example, a cast material of a 4000 series aluminum alloy. There are cases. In this way, a heat exchanger may be manufactured by joining members of different grades of aluminum alloy. In such a case, the lid 102 generally has a higher hardness than the extruded perforated pipe 101. Therefore, when friction stir welding is performed as shown in FIG. 8, the stirring pin G2 becomes the extruded perforated pipe 101. The material resistance received from the lid 102 side is larger than the material resistance received from the side. Therefore, it becomes difficult to stir different grades in a well-balanced manner by the stirring pin G2 of the rotary tool G, and there is a problem that cavity defects occur in the plasticized region after joining and the joining strength decreases.

Further, as shown in FIG. 8, when the stirring pin G2 is inserted into the butt portion J10, the stirring pin G2 is pushed in in the vertical direction until it reaches a predetermined depth, so that the frictional heat at the start position of frictional stirring becomes excessive. .. As a result, at the starting position, the metal on the lid 102 side is likely to be mixed into the extruded perforated pipe 101 side, which causes a problem of contributing to poor joining.

On the other hand, when the stirring pin G2 is pulled out from the butt portion J10 and separated, the stirring pin G2 is pulled out in the vertical direction, so that the frictional heat at the end position of frictional stirring becomes excessive. As a result, at the end position, the metal on the lid 102 side is likely to be mixed into the extruded perforated pipe 101 side, which causes a problem of contributing to poor joining.

From this point of view, it is an object of the present invention to provide a method for manufacturing a heat exchanger capable of suitably joining aluminum alloys of different grades.

In order to solve the above problems, the present invention is composed of an extruded perforated pipe having fins inside and a lid for sealing the opening of the extruded perforated pipe, and the extruded perforated pipe and the lid are combined. A method for manufacturing a heat exchanger to be joined by frictional stirring, wherein the lid has a bottom portion and a peripheral wall portion rising from the peripheral edge of the bottom portion, and the outer peripheral edge of the peripheral wall portion has a step side surface and a step side surface. A peripheral wall stepped portion having a stepped inclined surface that inclines toward the bottom side toward the outside is formed, and the extruded perforated pipe is fitted with the peripheral wall portion without the fins formed at the end. The extruded porous pipe has a fitting portion to be fitted, the extruded perforated pipe is formed of a second aluminum alloy, the lid is formed of a first aluminum alloy, and the first aluminum alloy is made of the second aluminum alloy. The rotary tool used for frictional stirring is provided with a stirring pin, and the stirring pin is tapered toward the tip side to fit the fitting portion of the extruded porous pipe. By inserting the peripheral wall portion of the lid, the inner peripheral surface of the extruded perforated pipe and the stepped side surface of the lid are overlapped, and the end surface of the extruded perforated pipe and the stepped inclined surface of the lid are overlapped. The butting step of forming a gap having a V-shaped cross section in the butt portion and the stirring pin of the rotating tool are inserted into the outer peripheral surface of the extruded perforated pipe, and the outer peripheral surface of the stirring pin is inserted into the lid. A predetermined depth along the set movement route set on the extruded perforated pipe side from the butt portion while flowing the second aluminum alloy into the gap in a state of being slightly in contact with the stepped inclined surface of the above. Including the main joining step of rubbing and stirring the butt portion around the outer peripheral surface of the extruded perforated pipe, in the main joining step, only the rotating stirring pin is further described as being more than the set movement route. After inserting at the start position set on the extruded perforated pipe side, the stirring pin is gradually pushed in until the predetermined depth is reached while moving the rotation center axis of the rotation tool to a position overlapping the set movement route. It is characterized by.

Further, the present invention is composed of an extruded perforated pipe having fins inside and a lid for sealing the opening of the extruded perforated pipe, and heat for joining the extruded perforated pipe and the lid by frictional stirring. A method of manufacturing a switch, the lid has a bottom portion and a peripheral wall portion rising from the peripheral edge of the bottom portion, and the outer peripheral edge of the peripheral wall portion has a step side surface and the bottom portion as it goes outward from the step side surface. A peripheral wall stepped portion having a stepped inclined surface inclined so as to be close to the side is formed, and the extruded perforated pipe has a fitting portion in which the fin is not formed at the end portion and the peripheral wall portion is fitted. The extruded perforated pipe is made of a second aluminum alloy, the lid is made of a first aluminum alloy, and the first aluminum alloy is a grade having a higher hardness than the second aluminum alloy. The rotary tool used for frictional stirring is provided with a stirring pin, and the stirring pin is tapered toward the tip side, and the peripheral wall of the lid body is fitted to the fitting portion of the extruded perforated pipe. By inserting the portion, the inner peripheral surface of the extruded perforated pipe and the stepped side surface of the lid are overlapped, and the end surface of the extruded perforated pipe and the stepped inclined surface of the lid are abutted into the butt portion. Only the butt step for forming a gap having a V-shaped cross section and the stirring pin of the rotating tool are inserted into the outer peripheral surface of the extruded perforated pipe, and the outer peripheral surface of the stirring pin is slightly on the stepped inclined surface of the lid. While flowing the second aluminum alloy into the gap in contact with the above, the extruded perforated pipe has a predetermined depth along a set movement route set on the extruded perforated pipe side of the butt portion. Including the main joining step of rubbing and stirring the butt portion around the outer peripheral surface, the stirring pin is inserted from the start position set on the set movement route in the main joining step, and the stirring pin is inserted in the traveling direction. The stirring pin is gradually pushed in until it reaches a predetermined height while being moved.

According to such a manufacturing method, the frictional heat between the lid and the extruded perforated pipe stirs and plastically fluidizes the second aluminum alloy mainly on the extruded perforated pipe side of the butt portion, and the lid and the extruded perforated pipe are formed at the butt portion. Can be joined. Further, since the outer peripheral surface of the stirring pin is kept in contact with the lid slightly, it is possible to minimize the mixing of the first aluminum alloy from the lid into the extruded perforated pipe. As a result, the second aluminum alloy on the extruded perforated pipe side is mainly frictionally agitated at the butt portion, so that a decrease in joint strength can be suppressed. Further, by gradually pushing the stirring pin until it reaches a predetermined depth while moving the rotating tool, it is possible to prevent the frictional heat from becoming excessive locally. This makes it possible to prevent the first aluminum alloy of the lid from being mixed into the extruded perforated pipe side on the set movement route.

Further, in the main joining step, the stirring pin is rotated at a predetermined rotation speed to perform frictional stirring, and when the stirring pin is inserted in the main joining step, the stirring is performed at a speed higher than the predetermined rotation speed. It is preferable to insert the pin in a rotated state and move it to the set movement route while gradually reducing the rotation speed.

According to such a manufacturing method, friction stir welding can be performed more preferably.

Further, the present invention is composed of an extruded perforated pipe having fins inside and a lid for sealing the opening of the extruded perforated pipe, and heat for joining the extruded perforated pipe and the lid by frictional stirring. A method of manufacturing a switch, the lid has a bottom portion and a peripheral wall portion rising from the peripheral edge of the bottom portion, and the outer peripheral edge of the peripheral wall portion has a step side surface and the bottom portion as it goes outward from the step side surface. A peripheral wall stepped portion having a stepped inclined surface inclined so as to be close to the side is formed, and the extruded perforated pipe has a fitting portion in which the fin is not formed at the end portion and the peripheral wall portion is fitted. The extruded perforated pipe is made of a second aluminum alloy, the lid is made of a first aluminum alloy, and the first aluminum alloy is a grade having a higher hardness than the second aluminum alloy. The rotary tool used for frictional stirring is provided with a stirring pin, and the stirring pin is tapered toward the tip side, and the peripheral wall of the lid body is fitted to the fitting portion of the extruded perforated pipe. By inserting the portion, the inner peripheral surface of the extruded perforated pipe and the stepped side surface of the lid are overlapped, and the end surface of the extruded perforated pipe and the stepped inclined surface of the lid are abutted into the butt portion. Only the butt step for forming a gap having a V-shaped cross section and the stirring pin of the rotating tool are inserted into the outer peripheral surface of the extruded perforated pipe, and the outer peripheral surface of the stirring pin is slightly on the stepped inclined surface of the lid. While flowing the second aluminum alloy into the gap in contact with the above, the extruded perforated pipe has a predetermined depth along a set movement route set on the extruded perforated pipe side of the butt portion. Including the main joining step of rubbing and stirring the butt portion around the outer peripheral surface, in the main joining step, the end position is set further on the extruded perforated pipe side than the set movement route, and the butt is set. After the friction stirring joint to the portion, the rotating tool is gradually pulled out while moving the rotating tool to the end position, and the rotating tool is separated from the extruded perforated pipe at the end position.

Further, the present invention is composed of an extruded perforated pipe having fins inside and a lid for sealing the opening of the extruded perforated pipe, and heat for joining the extruded perforated pipe and the lid by frictional stirring. A method of manufacturing a switch, the lid has a bottom portion and a peripheral wall portion rising from the peripheral edge of the bottom portion, and the outer peripheral edge of the peripheral wall portion has a step side surface and the bottom portion as it goes outward from the step side surface. A peripheral wall stepped portion having a stepped inclined surface inclined so as to be close to the side is formed, and the extruded perforated pipe has a fitting portion in which the fin is not formed at the end portion and the peripheral wall portion is fitted. The extruded perforated pipe is made of a second aluminum alloy, the lid is made of a first aluminum alloy, and the first aluminum alloy is a grade having a higher hardness than the second aluminum alloy. The rotary tool used for frictional stirring is provided with a stirring pin, and the stirring pin is tapered toward the tip side, and the peripheral wall of the lid body is fitted to the fitting portion of the extruded perforated pipe. By inserting the portion, the inner peripheral surface of the extruded perforated pipe and the stepped side surface of the lid are overlapped, and the end surface of the extruded perforated pipe and the stepped inclined surface of the lid are abutted against the butt portion. Only the butt step for forming a gap having a V-shaped cross section and the stirring pin of the rotating tool are inserted into the outer peripheral surface of the extruded perforated pipe, and the outer peripheral surface of the stirring pin is slightly on the stepped inclined surface of the lid. While flowing the second aluminum alloy into the gap in contact with the above, the extruded perforated pipe has a predetermined depth along a set movement route set on the extruded perforated pipe side of the butt portion. Including the main joining step of rubbing and stirring the butt portion around the outer peripheral surface, in the main joining step, the end position is set on the set movement route, and after the friction stirring joining to the butt portion. The rotating tool is gradually pulled out while moving the rotating tool to the end position, and the rotating tool is separated from the extruded perforated pipe at the end position.

According to such a manufacturing method, the frictional heat between the lid and the extruded perforated pipe stirs and plastically fluidizes the second aluminum alloy mainly on the extruded perforated pipe side of the butt portion, and the lid and the extruded perforated pipe are formed at the butt portion. Can be joined. Further, since the outer peripheral surface of the stirring pin is kept in contact with the lid slightly, it is possible to minimize the mixing of the first aluminum alloy from the lid into the extruded perforated pipe. As a result, the second aluminum alloy on the extruded perforated pipe side is mainly frictionally agitated at the butt portion, so that a decrease in joint strength can be suppressed. Further, by gradually pulling out the stirring pin while moving the rotating tool, it is possible to prevent the frictional heat from becoming excessive locally. This makes it possible to prevent the first aluminum alloy of the lid from being mixed into the extruded perforated pipe side on the set movement route.

Further, in the main joining step, the stirring pin is rotated at a predetermined rotation speed to perform frictional stirring, and when the stirring pin is separated in the main joining step, the rotation speed is gradually increased from the predetermined rotation speed. It is preferable to move it to the end position while raising it.

According to such a manufacturing method, friction stir welding can be performed more preferably.

Further, in the butt step, it is preferable to form the extruded perforated pipe and the lid so that the outer peripheral surface of the extruded perforated pipe is on the outer side of the outer peripheral surface of the lid.

According to such a manufacturing method, it is possible to prevent a metal shortage at the joint.

Further, it is preferable to set the rotation direction and the traveling direction of the rotation tool so that the butt portion side is the advancing side.

According to such a manufacturing method, friction stir welding on the butt portion side is promoted, and more suitable joining can be performed.

Further, in the main joining step, it is preferable that the tip of the stirring pin penetrates the stepped side surface of the lid and circulates around the outer peripheral surface of the extruded perforated pipe to frictionally stir the butt portion.

According to such a manufacturing method, the lid body and the extruded perforated pipe can be more preferably joined.

Further, it is preferable that the first aluminum alloy is made of a cast material and the second aluminum alloy is made of a wrought material.

According to the method for manufacturing a heat exchanger according to the present invention, aluminum alloys of different grades can be suitably joined.

It is an exploded perspective view which shows the heat exchanger which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the butt process of the manufacturing method of the heat exchanger which concerns on 1st Embodiment. It is a schematic diagram which shows the start position of the main joining process of the manufacturing method of the heat exchanger which concerns on 1st Embodiment. It is sectional drawing which shows the main joining process of the manufacturing method of the heat exchanger which concerns on 1st Embodiment. It is a schematic diagram which shows the end position of this joining process of the manufacturing method of the heat exchanger which concerns on 1st Embodiment. It is a schematic diagram which shows the start position of this joining process of the manufacturing method of the heat exchanger which concerns on 2nd Embodiment of this invention. It is a schematic diagram which shows the end position of this joining process of the manufacturing method of the heat exchanger which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the manufacturing method of the conventional heat exchanger.

[First Embodiment]
Embodiments of the present invention will be described with reference to the drawings as appropriate. As shown in FIG. 1, the heat exchanger 1 according to the first embodiment is composed of an extruded perforated pipe 2 and lids 3 and 3 arranged at both ends of the extruded perforated pipe 2. The heat exchanger 1 is a device that cools a heating element that is arranged by circulating a fluid inside. The extruded perforated pipe 2 and the lids 3 and 3 are integrated by friction stir welding.

The extruded perforated pipe 2 is mainly composed of a main body 11 and a plurality of fins 12. In this embodiment, the extruded perforated pipe 2 is formed mainly containing a second aluminum alloy. The second aluminum alloy is formed of, for example, an aluminum alloy wrought material such as JIS A1050, A1100, A6063. The extruded perforated pipe 2 is an extruded shape member made of a second aluminum alloy.

The main body 11 has a tubular shape. The side portions 11a and 11b of the main body portion 11 are curved so as to be convex outward (outside in the width direction of the main body portion 11). The substrate portions 11c and 11d of the main body portion 11 are flat and face each other in parallel. That is, the cross section of the main body 11 has an oblong shape. The fins 12 are perpendicular to the substrate portions 11c and 11d. The fins 12 extend in the pushing direction of the main body 11, and are formed in parallel with each other. A hole 13 having a rectangular cross section through which a fluid flows is formed between the adjacent fins 12.

Fitting portions 14 to which fins 12 are not formed are formed in the openings at both ends of the extruded perforated pipe 2. The fitting portion 14 is a portion into which the peripheral wall portion 22 of the lid body 3, which will be described later, is inserted. The fitting portion 14 is formed by cutting both ends of the fin 12. The shape of the extruded perforated pipe 2 is not limited to the above-mentioned shape. For example, the cross section of the extruded perforated pipe 2 (cross section perpendicular to the extrusion direction) may be circular, elliptical, or square.

The lids 3 and 3 are members that seal the openings at both ends of the extruded perforated pipe 2. The lids 3 and 3 have the same shape. The lid 3 has a bottom portion 21 and a peripheral wall portion 22. The bottom portion 21 is a plate-shaped member having an oval shape. The outer shape of the bottom portion 21 is substantially the same as the outer shape of the main body portion 11 of the extruded perforated pipe 2 so as to seal the opening of the extruded perforated pipe 2. The peripheral wall portion 22 is a portion that rises vertically from the peripheral edge portion of the bottom portion 21. The peripheral wall portion 22 is formed in an oval frame shape along the shape of the bottom portion 21. A concave header flow path 24 is formed by the bottom portion 21 and the peripheral wall portion 22.

The material of the lid 3 is not particularly limited as long as it is a metal capable of friction stir welding, but in the present embodiment, it is formed mainly containing a first aluminum alloy. The first aluminum alloy is a material having a higher hardness than the second aluminum alloy. As the first aluminum alloy, for example, an aluminum alloy cast material such as JISH5302 ADC12 (Al—Si—Cu system) is used.

As shown in FIG. 2, a peripheral wall step portion 23 composed of a step side surface 23a and a step inclined surface 23b rising from the step side surface 23a is formed on the outer peripheral edge of the peripheral wall portion 22. The peripheral wall step portion 23 is formed over the entire peripheral direction. The step side surface 23a is parallel to the extrusion direction. The step inclined surface 23b is inclined so as to approach the bottom portion 21 from the step side surface 23a toward the outside (outside in the width direction of the main body portion 11). In other words, the step inclined surface 23b is inclined so as to be separated from the main body portion 11 toward the outside. The inclination angle β of the step inclined surface 23b is a constant inclination angle.

The outer peripheral surface 11f of the extruded perforated pipe 2 and the outer peripheral surface 22b of the peripheral wall portion 22 may be flush with each other, but in the present embodiment, the extruded perforated pipe 2 and the lid 3 are subjected to the butt step described later, and then the peripheral wall portion is formed. The outer peripheral surface 11f of the extruded perforated pipe 2 is set to be on the outer side of the outer peripheral surface 22b of 22. In other words, the height (thickness) dimension of the end surface 11e of the extruded perforated pipe 2 is set to be larger than the height dimension of the stepped inclined surface 23b.

Next, a method of manufacturing the heat exchanger according to the present embodiment will be described. In the heat exchanger manufacturing method according to the present embodiment, a preparation step, a butt step, and a main joining step are performed.

The preparation step is a step of preparing the extruded perforated pipe 2 and the lid 3. The extruded perforated pipe 2 and the lid 3 are not particularly limited in terms of manufacturing method, but the extruded perforated pipe 2 is molded by, for example, extrusion molding. The lid 3 is molded by die casting, for example.

The butt step is a step of butt-butting the lid 3 against the extruded perforated pipe 2 as shown in FIG. In the butt step, the fitting portion 14 of the extruded perforated pipe 2 is fitted to the peripheral wall portion 22 of the lid body 3. As a result, the stepped inclined surface 23b of the lid 3 and the end surface 11e of the extruded perforated tube 2 are abutted to form the butt portion J1, and the stepped side surface 23a of the lid 3 and the inner peripheral surface 11g of the extruded perforated tube 2 are formed. And are overlapped to form a butt portion J2. The end face 22a of the peripheral wall portion 22 and the end face 12a of the fin 12 are in contact with each other or face each other with a slight gap. The butt portions J1 and J2 are formed over the circumferential direction. A gap having a V-shaped cross section is formed in the butt portion J1.

As shown in FIGS. 3 and 4, this joining step is a step of friction stir welding the butt portion J1 using the rotary tool F. First, the "set movement route L1" (dashed line) is set at a position away from the lid 3 with respect to the butt portion J1. The set movement route L1 is a movement route of the rotation tool F necessary for joining the butt portion J1 in the main joining step described later. The set movement route L1 will be described in detail later.

As shown in FIG. 4, the rotation tool F is composed of a connecting portion F1 and a stirring pin F2. The rotary tool F is made of, for example, tool steel. The connecting portion F1 is a portion connected to the rotating shaft of the friction stir device (not shown). The connecting portion F1 has a columnar shape, and a screw hole (not shown) for fastening a bolt is formed.

The stirring pin F2 hangs down from the connecting portion F1 and is coaxial with the connecting portion F1. The stirring pin F2 is tapered as it is separated from the connecting portion F1. The inclination angle α of the stirring pin F2 with respect to the rotation center axis Z is the same as the inclination angle β (FIG. 2) of the step inclined surface 23b with respect to the vertical plane. The tip of the stirring pin F2 is provided with a flat flat surface F3.

A spiral groove is engraved on the outer peripheral surface of the stirring pin F2. In the present embodiment, in order to rotate the rotation tool F clockwise, the spiral groove is formed counterclockwise from the base end to the tip end. In other words, the spiral groove is formed counterclockwise when viewed from above when the spiral groove is traced from the base end to the tip end.

When the rotation tool F is rotated counterclockwise, it is preferable to form the spiral groove clockwise from the base end to the tip end. In other words, the spiral groove in this case is formed clockwise when viewed from above when the spiral groove is traced from the base end to the tip end. By setting the spiral groove in this way, the metal plastically fluidized during frictional stirring is guided to the tip side of the stirring pin F2 by the spiral groove. As a result, the amount of metal that overflows to the outside of the metal member to be joined (extruded perforated pipe 2 and lid 3) can be reduced. The rotation tool F may be attached to, for example, a robot arm having a rotation driving means such as a spindle unit at its tip.

As shown in FIG. 3, in the main joining step, the intrusion section from the start position SP1 to the intermediate point S1, the main section from the intermediate point S1 on the set movement route L1 to the intermediate point S2, and the intermediate point S2 Three sections of the detachment section from to the end position EP1 are continuously rubbed and joined. The intermediate points S1 and S2 are set on the set movement route L1. The start position SP1 is set in the main body 11 of the extruded perforated pipe 2 at a position separated from the lid 3 with respect to the set movement route L1. In the present embodiment, the start position SP1 is set at a position where the angle formed by the line segment connecting the start position SP1 and the intermediate point S1 and the set movement route L1 is blunt.

In the closet section of this joining step, friction stir welding is performed from the start position SP1 to the intermediate point S1. In the closet section, the stirring pin F2 rotated clockwise is inserted into the start position SP1 while the rotation center axis Z is perpendicular to the outer peripheral surface 11f of the main body 11, and is relatively moved to the intermediate point S1. At this time, the stirring pin F2 is gradually pushed in so as to reach a preset "predetermined depth" by at least reaching the intermediate point S1. That is, the rotation tool F is gradually lowered while being moved to the set movement route L1 without staying in one place. When the rotation tool F reaches the intermediate point S1, the section shifts to this section as it is.

In this section, as shown in FIG. 4, the rotation tool F is made to go around along the set movement route L1. In this section, when the intermediate point S1 is reached, the outer peripheral surface of the stirring pin F2 and the step inclined surface 23b are set to be parallel. Further, when the intermediate point S1 is reached, the outer peripheral surface of the stirring pin F2 and the stepped inclined surface 23b are set to slightly contact each other. The rotation center axis Z of the rotation tool F and the outer peripheral surface 11f of the main body 11 are set to be vertical, and the rotation tool F is relatively moved along the butt portion J1 while maintaining these.

The contact allowance (offset amount) N between the outer peripheral surface of the stirring pin F2 and the stepped inclined surface 23b is set, for example, between 0 <N ≦ 1.0 mm, preferably 0 <N ≦ 0.85 mm. However, it is more preferably set between 0 <N ≦ 0.65 mm.

As shown in FIG. 4, the set movement route L1 shows a locus through which the center of the flat surface F3 passes. That is, the set movement route L1 is set so that the step inclined surface 23b and the outer peripheral surface of the stirring pin F2 are made parallel to each other and slightly contact each other in the circumferential direction of the butt portion J1. In this section, when the rotation tool F is viewed from above, the rotation tool F is moved so that the center of the flat surface F3 overlaps with the set movement route L1. The "predetermined depth" of the stirring pin F2 may be appropriately set, but in the present embodiment, the flat surface F3 of the rotating tool F is inserted to a position where it penetrates the step side surface 23a. As a result, the butt portion J2 can also be reliably joined.

If the outer peripheral surface of the stirring pin F2 is set so as not to come into contact with the stepped inclined surface 23b, the joint strength of the butt portion J1 is lowered. On the other hand, if the contact allowance N of the stepped inclined surface 23b of the stirring pin F2 exceeds 1.0 mm, a large amount of the first aluminum alloy of the lid 3 may be mixed into the extruded perforated pipe 2 side, resulting in poor joining.

As shown in FIG. 5, when the stirring pin F2 reaches the intermediate point S2 by rotating the rotating tool F around the rotation tool F, the rotation tool F shifts to the leaving section as it is. In the detachment section, the stirring pin F2 is gradually pulled out (raised) from the intermediate point S2 toward the end position EP1, and the stirring pin F2 is detached from the extruded porous tube 2 at the end position EP1. That is, the rotation tool F is gradually pulled out while being moved to the end position EP1 without staying in one place. The end position EP1 is set at a position where the angle formed by the line segment connecting the end position EP1 and the intermediate point S2 and the set movement route L1 is an obtuse angle. A plasticized region W1 is formed in the movement locus of the rotation tool F. When the friction stir welding between the extruded porous pipe 2 and the lid 3 on one end side is completed as described above, the friction stir welding between the extruded porous pipe 2 and the lid 3 on the other end side is performed in the same manner.

According to the method for manufacturing a heat exchanger in the present embodiment described above, the frictional heat between the extruded perforated pipe 2 and the stirring pin F2 stirs the second aluminum alloy mainly on the extruded perforated pipe 2 side of the butt portion J1 to make it plastic. It is fluidized, and the end surface 11e of the extruded perforated pipe 2 and the stepped inclined surface 23b of the lid 3 can be joined at the butt portion J1.

Further, since the outer peripheral surface of the stirring pin F2 is kept slightly in contact with the stepped inclined surface 23b, it is possible to minimize the mixing of the first aluminum alloy from the lid 3 into the extruded perforated pipe 2. As a result, in the butt portion J1, the second aluminum alloy on the extruded perforated pipe 2 side is mainly frictionally agitated, so that a decrease in joint strength can be suppressed. That is, in this joining step, the imbalance of the material resistance received by the stirring pin F2 on one side and the other side with respect to the rotation center axis Z of the stirring pin F2 can be minimized. Further, since the outer peripheral surface of the stirring pin F2 and the stepped inclined surface 23b of the lid 3 are set in parallel, the plastic fluid material is frictionally agitated in a well-balanced manner, and a decrease in joint strength can be suppressed.

Further, in the closet section of the main joining step, the set movement route is gradually pushed in until the stirring pin F2 reaches a predetermined depth while moving the rotation tool F from the start position SP1 to a position overlapping the set movement route L1. It is possible to prevent the rotation tool F from stopping on L1 and causing the frictional heat to become excessive.
Similarly, in the detachment section of the main joining step, the stirring pin F2 is gradually pulled out from a predetermined depth while moving the rotation tool F from the set movement route L1 to the end position EP1 to detach the stirring pin F2 on the set movement route L1. It is possible to prevent the rotation tool F from stopping and excessive frictional heat.

As a result, it is possible to prevent the frictional heat from becoming excessive on the set movement route L1 and excessive mixing of the first aluminum alloy from the lid 3 into the extruded perforated pipe 2 resulting in poor joining.

Further, in the main joining step, the positions of the start position SP1 and the end position EP1 may be appropriately set, but the angle formed by the start position SP1 and the set movement route L1 and the angle formed by the end position EP1 and the set movement route L1 are different. By setting the angle to be obtuse, it is possible to smoothly shift to the main section or the departure section at the intermediate points S1 and S2 without reducing the moving speed of the rotation tool F. As a result, it is possible to prevent the frictional heat from becoming excessive due to the rotation tool F stopping or the moving speed decreasing on the set movement route L1. The rotation tool F may be moved from the start position SP1 to the set movement route L1 so that the locus of the rotation tool F draws an arc when viewed from above. Similarly, the rotation tool F may be moved from the set movement route L1 to the end position EP1 so that the locus of the rotation tool F draws an arc when viewed from above.

Further, in the main joining step of the present embodiment, the rotation direction and the traveling direction of the rotation tool F may be appropriately set, but the lid 3 side (of the plasticized region W1 formed in the movement locus of the rotation tool F) ( The rotation direction and the traveling direction of the rotation tool F were set so that the butt portion J1 side) was on the shear side and the extruded perforated pipe 2 side was on the flow side. By setting the lid 3 side to be the shear side, the stirring action by the stirring pin F2 around the butt portion J1 is enhanced, the temperature rise in the butt portion J1 can be expected, and the extruded perforated pipe 2 and the lid in the butt portion J1. The body 3 can be joined more reliably.

The shear side (Advancing side) means the side where the relative speed of the outer circumference of the rotating tool with respect to the jointed portion is the value obtained by adding the magnitude of the moving speed to the magnitude of the tangential velocity on the outer circumference of the rotating tool. .. On the other hand, the flow side (Retreating side) refers to the side where the relative speed of the rotating tool with respect to the jointed portion becomes low due to the rotation of the rotating tool in the direction opposite to the moving direction of the rotating tool.

Further, the first aluminum alloy of the lid 3 is a material having a higher hardness than the second aluminum alloy of the extruded porous tube 2. Thereby, the durability of the heat exchanger 1 can be enhanced. Further, it is preferable that the first aluminum alloy of the lid 3 is an aluminum alloy casting material and the second aluminum alloy of the extruded perforated pipe 2 is an aluminum alloy wrought material. By using, for example, an Al—Si—Cu based aluminum alloy casting material such as JIS H5302 ADC12 as the first aluminum alloy, the castability, strength, machinability, etc. of the lid 3 can be improved. Further, by using, for example, JIS A1000 series or A6000 series as the second aluminum alloy, the processability and thermal conductivity of the extruded porous tube 2 can be improved.

Further, in this joining step, since the entire circumference of the butt portion J1 can be subjected to friction stir welding, the airtightness and watertightness of the heat exchanger can be improved. Further, at the end portion of the main joining step, the rotation tool F is made to move toward the end position EP1 after completely passing through the intermediate point S1. That is, the airtightness and watertightness can be further improved by overlapping the ends of the plasticized region W1 formed by this joining step with each other.

Further, in this joining step, since friction stir welding is performed with the base end side of the stirring pin F2 of the rotary tool F exposed, the load acting on the friction stir welding device can be reduced. Further, in the present embodiment, after the butt step is performed, the outer peripheral surface 11f of the extruded perforated pipe 2 is set to be outside the outer peripheral surface 22b of the peripheral wall portion 22. As a result, it is possible to further prevent the metal shortage of the butt portion J1 when performing friction stir welding.

Further, by providing the lid body 3 with the header flow path 24, the fluid flowing in or out of the hole 13 can be collected.

In this joining step, the rotation speed of the rotation tool F may be constant, but may be variable. In the closet section of the main joining step, if the rotation speed of the rotation tool F at the start position SP1 is V1 and the rotation speed of the rotation tool F in this section is V2, V1> V2 may be satisfied. The rotation speed V2 is a preset constant rotation speed in the set movement route L1. That is, at the start position SP1, the rotation speed may be set high, and the rotation speed may be gradually reduced in the closet section to shift to the main section.

Further, in the detachment section of the first main joining step, if the rotation speed of the rotation tool F in this section is V2 and the rotation speed of the rotation tool F at the end position EP1 is V3, V3> V2 may be satisfied. That is, after shifting to the detachment section, the rotation tool F may be detached from the extruded perforated pipe 2 while gradually increasing the rotation speed toward the end position EP1. When the rotary tool F is pushed into the extruded perforated pipe 2 or separated from the extruded perforated pipe 2, by setting as described above, it is possible to compensate for the small pressing pressure in the indentation section or the detachment section at the rotation speed. Therefore, friction stir welding can be preferably performed.

[Second Embodiment]
Next, a method for manufacturing the heat exchanger according to the second embodiment of the present invention will be described. In the second embodiment, as shown in FIGS. 6 and 7, the first embodiment is set in that the positions of the start position SP1, the intermediate points S1 and S2, and the end position EP1 in the main joining process are all set on the set movement route L1. Different from the form. In the second embodiment, the parts different from the first embodiment will be mainly described.

In the manufacture of the heat exchanger according to the second embodiment, the preparation step, the butt step, and the main joining step are performed. The preparation step and the butt step are the same as those in the first embodiment.

In this joining step, as shown in FIG. 6, the start position SP1 is set on the set movement route L1. In this joining process, the intrusion section from the start position SP1 to the intermediate point S1, the main section from the intermediate point S1 on the set movement route L1 to the intermediate point S2, and the departure from the intermediate point S2 to the end position EP1. Friction stir welding is performed continuously for three sections.

In the closet section, as shown in FIG. 6, friction stir welding is performed from the start position SP1 on the set movement route to the intermediate point S1. In the intrusion section, the stirring pin F2 rotated clockwise is inserted into the start position SP1 while the rotation center axis Z is perpendicular to the outer peripheral surface 11f of the extruded perforated tube 2, and is relatively moved to the intermediate point S1. At this time, the stirring pin F2 is gradually pushed in so as to reach a preset "predetermined depth" by at least reaching the intermediate point S1.

Further, in the indentation section, while moving the rotation tool F, when the intermediate point S1 is reached, the outer peripheral surface of the stirring pin F2 and the step inclined surface 23b are set to be parallel to each other, and the stirring pin F2 is set. The outer peripheral surface and the stepped inclined surface 23b are set so as to be in slight contact with each other. Then, while maintaining that state, the process shifts to friction stir welding in this section. The contact allowance (offset amount) N between the outer peripheral surface of the stirring pin F2 and the stepped inclined surface 23b and the setting of the set movement route L1 are the same as those in the first embodiment.

As shown in FIG. 7, when the stirring pin F2 reaches the intermediate point S2 by rotating the rotating tool F around the rotation tool F, the rotation tool F shifts to the leaving section as it is. In the departure section, as shown in FIG. 7, the stirring pin F2 is gradually pulled out (moved upward) from the intermediate point S2 to the end position EP1 to end the set on the set movement route L1. At position EP1, the stirring pin F2 is separated from the extruded perforated tube 2.

The method for manufacturing the heat exchanger according to the second embodiment described above can also achieve substantially the same effect as that of the first embodiment. As in the second embodiment, the start position SP1 and the end position EP1 in the main joining step may be set on the set movement route L1.

1 Heat exchanger 2 Extruded perforated pipe 3 Lid F Rotating tool F2 Stirring pin F3 Flat surface J1 Butt SP1 Start position EP1 End position W1 Plasticization area

Claims (12)

A method for manufacturing a heat exchanger, which is composed of an extruded perforated pipe having fins inside and a lid for sealing an opening of the extruded perforated pipe, and joins the extruded perforated pipe and the lid by friction stir welding. There,
The lid has a bottom portion and a peripheral wall portion that rises from the peripheral edge of the bottom portion, and a stepped side surface and a stepped portion that inclines toward the bottom side toward the outside from the stepped side surface on the outer peripheral edge of the peripheral wall portion. Forming a peripheral wall stepped portion having an inclined surface,
The extruded perforated pipe has a fitting portion in which the fin is not formed at the end portion and the peripheral wall portion is fitted.
The extruded perforated pipe is formed of a second aluminum alloy, the lid is made of a first aluminum alloy, and the first aluminum alloy is a grade having a higher hardness than the second aluminum alloy.
The rotary tool used for friction stirring is equipped with a stirring pin, and the stirring pin is tapered toward the tip side.
By inserting the peripheral wall portion of the lid into the fitting portion of the extruded perforated pipe, the inner peripheral surface of the extruded perforated pipe and the stepped side surface of the lid are overlapped, and the end surface of the extruded perforated pipe is overlapped. And the butt step of abutting the stepped inclined surface of the lid body to form a gap having a V-shaped cross section in the butt portion.
Only the stirring pin of the rotating tool that rotates is inserted into the outer peripheral surface of the extruded perforated pipe, and the outer peripheral surface of the stirring pin is slightly brought into contact with the stepped inclined surface of the lid, and the second is inserted into the gap. While flowing the aluminum alloy, the butt portion is rubbed around the outer peripheral surface of the extruded perforated pipe at a predetermined depth along a set movement route set on the extruded perforated pipe side of the butt portion. Including the main joining step of stirring,
In the main joining step, after inserting only the rotating stirring pin at the start position set on the extruded perforated pipe side of the set movement route, the rotation center axis of the rotation tool overlaps with the set movement route. A method for manufacturing a heat exchanger, which comprises gradually pushing in the stirring pin until the predetermined depth is reached while moving the stirring pin to a position. In the main joining step, the stirring pin is rotated at a predetermined rotation speed to perform frictional stirring.
When the stirring pin is inserted in the main joining step, the stirring pin is inserted in a state of being rotated at a speed higher than the predetermined rotation speed, and is moved to the set movement route while gradually reducing the rotation speed. The method for manufacturing a heat exchanger according to claim 1, wherein the heat exchanger is manufactured. A method for manufacturing a heat exchanger, which is composed of an extruded perforated pipe having fins inside and a lid for sealing an opening of the extruded perforated pipe, and joins the extruded perforated pipe and the lid by friction stir welding. There,
The lid has a bottom portion and a peripheral wall portion that rises from the peripheral edge of the bottom portion, and a stepped side surface and a stepped portion that inclines toward the bottom side toward the outside from the stepped side surface on the outer peripheral edge of the peripheral wall portion. Forming a peripheral wall stepped portion having an inclined surface,
The extruded perforated pipe has a fitting portion in which the fin is not formed at the end portion and the peripheral wall portion is fitted.
The extruded perforated pipe is formed of a second aluminum alloy, the lid is made of a first aluminum alloy, and the first aluminum alloy is a grade having a higher hardness than the second aluminum alloy.
The rotary tool used for friction stirring is equipped with a stirring pin, and the stirring pin is tapered toward the tip side.
By inserting the peripheral wall portion of the lid into the fitting portion of the extruded perforated pipe, the inner peripheral surface of the extruded perforated pipe and the stepped side surface of the lid are overlapped, and the end surface of the extruded perforated pipe is overlapped. And the butt step of abutting the stepped inclined surface of the lid body to form a gap having a V-shaped cross section in the butt portion.
Only the stirring pin of the rotating tool that rotates is inserted into the outer peripheral surface of the extruded perforated pipe, and the outer peripheral surface of the stirring pin is slightly brought into contact with the stepped inclined surface of the lid, and the second is inserted into the gap. While flowing the aluminum alloy, the butt portion is rubbed around the outer peripheral surface of the extruded perforated pipe at a predetermined depth along a set movement route set on the extruded perforated pipe side of the butt portion. Including the main joining step of stirring,
In the main joining step, the stirring pin is inserted from a start position set on the set movement route, and the stirring pin is gradually pushed in until it reaches a predetermined height while moving in the traveling direction. How to make a switch. In the main joining step, the stirring pin is rotated at a predetermined rotation speed to perform frictional stirring.
When the stirring pin is inserted in the main joining step, the stirring pin is inserted in a state of being rotated at a speed higher than the predetermined rotation speed, and is moved to the set movement route while gradually reducing the rotation speed. The method for manufacturing a heat exchanger according to claim 3, wherein the heat exchanger is manufactured. A method for manufacturing a heat exchanger, which is composed of an extruded perforated pipe having fins inside and a lid for sealing an opening of the extruded perforated pipe, and joins the extruded perforated pipe and the lid by friction stir welding. There,
The lid has a bottom portion and a peripheral wall portion that rises from the peripheral edge of the bottom portion, and a stepped side surface and a stepped portion that inclines toward the bottom side toward the outside from the stepped side surface on the outer peripheral edge of the peripheral wall portion. Forming a peripheral wall stepped portion having an inclined surface,
The extruded perforated tube has a fitting portion in which the fin is not formed at the end portion and the peripheral wall portion is fitted.
The extruded perforated pipe is formed of a second aluminum alloy, the lid is made of a first aluminum alloy, and the first aluminum alloy is a grade having a higher hardness than the second aluminum alloy.
The rotary tool used for friction stirring is equipped with a stirring pin, and the stirring pin is tapered toward the tip side.
By inserting the peripheral wall portion of the lid into the fitting portion of the extruded perforated pipe, the inner peripheral surface of the extruded perforated pipe and the stepped side surface of the lid are overlapped, and the end surface of the extruded perforated pipe is overlapped. And the butt step of abutting the stepped inclined surface of the lid body to form a gap having a V-shaped cross section in the butt portion.
Only the stirring pin of the rotating tool that rotates is inserted into the outer peripheral surface of the extruded perforated pipe, and the outer peripheral surface of the stirring pin is slightly brought into contact with the stepped inclined surface of the lid, and the second is inserted into the gap. While flowing the aluminum alloy, the butt portion is rubbed around the outer peripheral surface of the extruded perforated pipe at a predetermined depth along a set movement route set on the extruded perforated pipe side of the butt portion. Including the main joining step of stirring,
In the main joining step, the end position is set further on the extruded perforated pipe side than the set movement route, and after friction stir welding with respect to the butt portion, the stirring pin is moved while moving the rotating tool to the end position. A method for manufacturing a heat exchanger, which comprises gradually pulling out the rotary tool from the extruded perforated tube at the end position. In the main joining step, the stirring pin is rotated at a predetermined rotation speed to perform frictional stirring.
The method for manufacturing a heat exchanger according to claim 5, wherein when the stirring pin is detached in the main joining step, the stirring pin is moved to the end position while gradually increasing the rotation speed from the predetermined rotation speed. A method for manufacturing a heat exchanger, which is composed of an extruded perforated pipe having fins inside and a lid for sealing an opening of the extruded perforated pipe, and joins the extruded perforated pipe and the lid by friction stir welding. There,
The lid has a bottom portion and a peripheral wall portion that rises from the peripheral edge of the bottom portion, and a stepped side surface and a stepped portion that inclines toward the bottom side toward the outside from the stepped side surface on the outer peripheral edge of the peripheral wall portion. Forming a peripheral wall stepped portion having an inclined surface,
The extruded perforated pipe has a fitting portion in which the fin is not formed at the end portion and the peripheral wall portion is fitted.
The extruded perforated pipe is formed of a second aluminum alloy, the lid is made of a first aluminum alloy, and the first aluminum alloy is a grade having a higher hardness than the second aluminum alloy.
The rotary tool used for friction stirring is equipped with a stirring pin, and the stirring pin is tapered toward the tip side.
By inserting the peripheral wall portion of the lid into the fitting portion of the extruded perforated pipe, the inner peripheral surface of the extruded perforated pipe and the stepped side surface of the lid are overlapped, and the end surface of the extruded perforated pipe is overlapped. And the butt step of abutting the stepped inclined surface of the lid body to form a gap having a V-shaped cross section in the butt portion.
Only the stirring pin of the rotating tool that rotates is inserted into the outer peripheral surface of the extruded perforated pipe, and the outer peripheral surface of the stirring pin is slightly brought into contact with the stepped inclined surface of the lid, and the second is inserted into the gap. While flowing the aluminum alloy, the butt portion is rubbed around the outer peripheral surface of the extruded perforated pipe at a predetermined depth along a set movement route set on the extruded perforated pipe side of the butt portion. Including the main joining step of stirring,
In the main joining step, an end position is set on the set movement route, and after friction stir welding with respect to the butt portion, the stirring pin is gradually pulled out while moving the rotation tool to the end position to reach the end position. A method for manufacturing a heat exchanger, which comprises separating the rotary tool from the extruded perforated pipe. In the main joining step, the stirring pin is rotated at a predetermined rotation speed to perform frictional stirring.
The method for manufacturing a heat exchanger according to claim 7, wherein when the stirring pin is detached in the main joining step, the stirring pin is moved to the end position while gradually increasing the rotation speed from the predetermined rotation speed. The butt step is characterized in that the extruded perforated pipe and the lid are formed so that the outer peripheral surface of the extruded perforated pipe is on the outer side of the outer peripheral surface of the lid. The method for manufacturing a heat exchanger according to any one of claims 8. The method for manufacturing a heat exchanger according to any one of claims 1 to 9, wherein the rotation direction and the traveling direction of the rotation tool are set so that the butt portion side is the advancing side. The present claim is characterized in that, in a state where the tip of the stirring pin penetrates the stepped side surface of the lid, the butt portion is frictionally agitated by circling around the outer peripheral surface of the extruded perforated pipe. The method for manufacturing a heat exchanger according to any one of claims 1 to 10. The method for manufacturing a heat exchanger according to any one of claims 1 to 11, wherein the first aluminum alloy is made of a cast material, and the second aluminum alloy is made of a wrought material.

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