JP2021079425A - Heat exchanger manufacturing method - Google Patents

Abstract

To provide a heat exchanger manufacturing method that can suitably weld an aluminium alloy made of different kinds of materials to each other.SOLUTION: A heat exchanger manufacturing method includes a main welding step in which a stirring pin F2 of a rotary tool F is inserted into an outer peripheral surface 11f of an extrusion polygonal pipe 2, and a butted part J1 is subjected to friction-stir by circling the part around at a predetermined depth along a set movement route L1, while flowing a second aluminium alloy into a gap, in a state where a lower end face of a shoulder part F1 is contacted with the outer peripheral surface 11f of the extrusion polygonal pipe 2 while slightly contacting an outer peripheral surface of the stirring pin F2 with a step inclined surface 23b of a lid body 3. After the stirring pin F2 that rotates is inserted into a start position SP1 set in a direction in which the pin is separated from the butted part J1 more than the set movement route L1, the stirring pin F2 is gradually pushed into up to the predetermined depth while moving a rotation center axis Z of the rotary tool F to a position overlapping with the set movement route L1.SELECTED DRAWING: Figure 5

Description

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

A method of manufacturing a heat exchanger using friction stir welding is being carried out. For example, Patent Document 1 describes a method for manufacturing a heat exchanger in which an extruded perforated pipe in which a plurality of holes are arranged side by side and a sealing body for sealing the openings of the extruded perforated pipe are joined by friction stir welding. It is disclosed.

In the conventional method of manufacturing a heat exchanger, an end face of an extruded perforated tube made of an aluminum alloy and a stepped portion formed on the outer periphery of the lid are abutted to form a butt portion, and then a rotation tool is applied to the butt portion. It is used to perform frictional stirring joining.

Japanese Unexamined Patent Publication No. 2016-74016

Here, a case where a relatively simple shape such as an extruded perforated pipe is formed of a wrought material of a 1000 series aluminum alloy, and a lid is formed of, for example, a cast material of a 4000 series aluminum alloy. There is. In this way, a heat exchanger may be manufactured by joining members of different grades of aluminum alloy. In such a case, the lid is generally harder than the extruded perforated pipe. Therefore, when friction stir welding is performed, the stirring pin receives a material resistance from the extruded perforated pipe side. The material resistance received from the lid side increases. Therefore, it becomes difficult to stir different grades in a well-balanced manner by the stirring pin of the rotating tool, and there is a problem that cavity defects occur in the plasticized region after joining and the joining strength decreases.

Further, when the stirring pin is inserted into the butt portion, 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 side is likely to be mixed into the extruded perforated pipe side, which causes a problem of contributing to poor joining.

On the other hand, when the stirring pin is pulled out from the butt portion and separated, the stirring pin 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 side is likely to be mixed into the extruded perforated pipe 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 rotating tool used for friction stirring is provided with a shoulder portion and a stirring pin that hangs down from the center of the lower end surface of the shoulder portion, and the stirring pin has a tapered shape. 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 extruded portion is formed. A butt step of abutting the end surface of the perforated pipe and the stepped inclined surface of the lid to form a gap having a V-shaped cross section in the butt portion, and a stirring pin of the rotating tool are placed on the outer peripheral surface of the extruded perforated pipe. With the outer peripheral surface of the stirring pin slightly in contact with the stepped inclined surface of the lid, and the lower end surface of the shoulder portion in contact with the outer peripheral surface of the extruded perforated pipe, the first (Ii) While flowing the aluminum alloy, the butt portion is made to go around the outer peripheral surface of the extruded porous pipe at a predetermined depth along a set movement route set on the extruded porous pipe side of the butt portion. In the main joining step, which includes a main joining step of rubbing and stirring, the rotating tool is inserted after the rotating stirring pin is inserted at a start position set in a direction further away from the butt portion than the set movement route. The stirring pin is gradually pushed in until the predetermined depth is reached while moving the rotation center axis of the above to a position overlapping the set movement route.

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 stepped side surface and the bottom portion as it goes outward from the stepped 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 shoulder portion and a stirring pin that hangs down from the center of the lower end surface of the shoulder portion. The stirring pin has a tapered shape and is extruded. By inserting the peripheral wall portion of the lid body into the fitting portion of the perforated pipe, the inner peripheral surface of the extruded perforated pipe and the stepped side surface of the lid body are overlapped, and the end surface of the extruded perforated pipe and the said A butt step of abutting the stepped inclined surface of the lid to form a gap having a V-shaped cross section in the butt portion, and a stirring pin of the rotating tool are inserted into the outer peripheral surface of the extruded perforated pipe, and the stirring pin is inserted. The second aluminum alloy is allowed to flow into the gap in a state where the lower end surface of the shoulder portion is in contact with the outer peripheral surface of the extruded perforated pipe while the outer peripheral surface of the lid is slightly in contact with the stepped inclined surface of the lid. However, this joining step of frictionally stirring the butt portion by making a circumference around the outer peripheral surface of the extruded porous pipe at a predetermined depth along a set movement route set on the extruded porous pipe side of the butt portion. In the main joining step, the stirring pin is inserted from the start position set on the set movement route, and the stirring pin is gradually pushed in until it reaches a predetermined depth while moving in the traveling direction. It is characterized by.

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, the generation of burrs can be suppressed by bringing the lower end surface of the shoulder portion into contact with the outer peripheral surface of the extruded perforated tube to hold down the plastic fluid material. Further, by gradually pushing the stirring pin until it reaches a predetermined depth while moving the rotation tool to a position overlapping the set movement route, it is possible to prevent the frictional heat from becoming excessive on the set movement route. Further, by gradually pushing the stirring pin until it reaches a predetermined depth while moving the rotation tool on the set movement route, it is possible to prevent the frictional heat from becoming excessive at one point on the set movement route. 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 present joining step, the rotation tool is rotated at a predetermined rotation speed to perform frictional stirring, and when the stirring pin is inserted in the main joining step, the rotation speed is higher than the predetermined rotation speed. It is preferable to insert the stirring pin in a state of being rotated at a speed and move the stirring pin 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 stepped side surface and the bottom portion as it goes outward from the stepped 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 shoulder portion and a stirring pin that hangs down from the center of the lower end surface of the shoulder portion. The stirring pin has a tapered shape and is extruded. By inserting the peripheral wall portion of the lid body into the fitting portion of the perforated pipe, the inner peripheral surface of the extruded perforated pipe and the stepped side surface of the lid body are overlapped, and the end surface of the extruded perforated pipe and the said A butt step of abutting the stepped inclined surface of the lid to form a gap having a V-shaped cross section in the butt portion, and a stirring pin of the rotating tool are inserted into the outer peripheral surface of the extruded perforated pipe, and the stirring pin is inserted. The second aluminum alloy is allowed to flow into the gap in a state where the lower end surface of the shoulder portion is in contact with the outer peripheral surface of the extruded perforated pipe while the outer peripheral surface of the lid is slightly in contact with the stepped inclined surface of the lid. However, this joining step of frictionally stirring the butt portion by making a circumference around the outer peripheral surface of the extruded porous pipe at a predetermined depth along a set movement route set on the extruded porous pipe side of the butt portion. In the main joining step, the end position is set in a direction further away from the butt portion than the set movement route, and after frictional stirring joining to the butt portion, the rotation tool is moved to the end position. The stirring pin is gradually pulled out while being moved, and the rotating tool is separated from the extruded perforated tube 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 stepped side surface and the bottom portion as it goes outward from the stepped 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 shoulder portion and a stirring pin that hangs down from the center of the lower end surface of the shoulder portion. The stirring pin has a tapered shape and is extruded. By inserting the peripheral wall portion of the lid body into the fitting portion of the perforated pipe, the inner peripheral surface of the extruded perforated pipe and the stepped side surface of the lid body are overlapped, and the end surface of the extruded perforated pipe and the said A butt step of abutting the stepped inclined surface of the lid to form a gap having a V-shaped cross section in the butt portion, and a stirring pin of the rotating tool are inserted into the outer peripheral surface of the extruded perforated pipe, and the stirring pin is inserted. The second aluminum alloy is allowed to flow into the gap in a state where the lower end surface of the shoulder portion is in contact with the outer peripheral surface of the extruded perforated pipe while the outer peripheral surface of the lid is slightly in contact with the stepped inclined surface of the lid. However, this joining step of frictionally stirring the butt portion by making a circumference around the outer peripheral surface of the extruded porous pipe at a predetermined depth along a set movement route set on the extruded porous pipe side of the butt portion. In the main joining step, the end position is set on the set movement route, and after friction stirring joining to the butt portion, the stirring pin is gradually moved while moving the rotation tool to the end position. It is characterized in that the rotating tool is separated from the extruded perforated pipe at the end position by pulling out.

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 tube. 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 bringing the lower end surface of the shoulder portion into contact with the outer peripheral surface of the extruded perforated pipe and pressing the plastic fluid material, the generation of burrs can be suppressed. Further, by gradually pulling out the stirring pin while moving the rotation tool toward the end position, it is possible to prevent the frictional heat from becoming excessive on the set movement route. Further, by gradually pulling out the stirring pin until it reaches a predetermined depth while moving the rotation tool on the set movement route, it is possible to prevent the frictional heat from becoming excessive at one point on the set movement route. 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 friction stir welding of the butt portion, and when the stirring pin is pulled out in the main joining step, the stirring pin is gradually pulled out from the predetermined rotation speed. It is preferable to move to the end position while increasing the rotation speed.

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 a side view which shows the rotation tool which concerns on embodiment of this invention. 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.

Embodiments of the present invention will be described with reference to the drawings as appropriate. First, the rotation tool used in the joining method according to the present embodiment will be described. The rotary tool is a tool used for friction stir welding. As shown in FIG. 1, the rotary tool F is made of, for example, tool steel, and is composed of a shoulder portion F1 and a stirring pin F2. The shoulder portion F1 is a portion that holds down the plastically fluidized metal. The shoulder portion F1 has a columnar shape. The lower end surface of the shoulder portion F1 may be flat or may be concave in order to prevent the fluidized metal from flowing out.

The stirring pin F2 hangs down from the center of the lower end surface of the shoulder portion F1 and is coaxial with the shoulder portion F1. The stirring pin F2 has a tapered shape. The stirring pin F2 is tapered as it is separated from the shoulder portion F1. 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, a spiral groove is carved counterclockwise from the base end to the tip end.

When rotating the rotation tool F counterclockwise, the spiral groove is carved clockwise from the base end to the tip end. In this way, the metal plastically fluidized by friction stir welding is guided by the spiral groove and moves to the tip side of the stirring pin F2. As a result, the amount of metal overflowing from the metal member to be joined (extruded perforated pipe 2, lid 3) can be reduced.

[First Embodiment]
Embodiments of the present invention will be described with reference to the drawings as appropriate. As shown in FIG. 2, 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 circulates a fluid inside to cool an arranged heating element. 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 the present 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 extrusion direction of the main body 11, and are formed in parallel with each other. A plurality of holes 13 having a rectangular cross section through which fluid flows are formed between the adjacent fins 12.

Fitting portions 14 on 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 tube 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 casting material such as JISH5302 ADC12 (Al—Si—Cu system) is used. In the present specification, the hardness refers to Brinell hardness, which can be measured by a method according to JIS Z 2243.

As shown in FIG. 3, 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 inclination angle β (see FIG. 3) of the step inclined surface 23b with respect to the vertical plane is the same as the inclination angle α (see FIG. 1) of the stirring pin F2 with respect to the rotation center axis Z.

The outer peripheral surface 11f of the extruded perforated tube 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 lid 3 is subjected to the butt step described later, and then the outer peripheral surface 22b of the peripheral wall portion 22 is performed. The outer peripheral surface 11f of the extruded porous tube 2 is set to be on the outer side. 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 method for manufacturing a heat exchanger 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. 4 and 5, 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, in the main joining step, the closet 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. The three sections of the detachment section from to the end position EP1 are continuously friction-stir welded. The intermediate points S1 and S2 are set on the set movement route L1. The start position SP1 is set at a position in the main body 11 of the extruded perforated pipe 2 so as to be separated from the butt portion J1 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 an obtuse angle.

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 intrusion section, the rotation tool F (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, instead of keeping the rotation tool F in one place, the rotation tool F is gradually lowered while being moved to the set movement route L1. When the rotation tool F reaches the intermediate point S1, the section shifts to this section as it is. Here, the "predetermined depth" means the depth at which the stirring pin F2 is inserted in this section from the intermediate point S1 to the intermediate point S2 on the set movement route L1.

In this section, as shown in FIG. 5, 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 stepped inclined surface 23b are parallel to each other, and the outer peripheral surface of the stirring pin F2 and the stepped inclined surface 23b are slightly in contact with each other. Set. At this time, at least by the contact between the outer peripheral surface of the stirring pin F2 and the lid 3, the first aluminum alloy on the lid 3 side is slightly scraped off, and the first aluminum alloy is mixed into the extruded perforated pipe 2. Further, the insertion depth is set so that the flat surface F3 of the stirring pin F2 penetrates the step side surface 23a while the lower end surface of the shoulder portion F1 and the outer peripheral surface 11f of the extruded perforated tube 2 are in contact with each other. It is preferable that the lower end surface of the shoulder portion F1 does not come into contact with the outer peripheral surface 22b of the peripheral wall portion 22. 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 while maintaining these, the rotation tool F is relatively moved along the butt portion J1.

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. 5, the set movement route L1 shows a trajectory 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 and the stepped inclined surface 23b are set so as not to come into contact with each other, 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. 6, 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 detachment 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 perforated pipe 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 in the main body 11 of the extruded perforated pipe 2 so as to be separated from the butt portion J1 with respect to the set movement route L1. In the present embodiment, the angle formed by the line segment connecting the end position EP1 and the intermediate point S2 and the set movement route L1 is set to 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 perforated pipe 2 and the lid 3 on one end side is completed as described above, the friction stir welding between the extruded perforated pipe 2 and the lid 3 on the other end side is performed in the same manner.

According to the method for manufacturing the heat exchanger in the present embodiment described above, the second aluminum alloy mainly on the extruded perforated pipe 2 side of the butt portion J1 is agitated by the frictional heat between the extruded perforated pipe 2 and the stirring pin F2 to be 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, by bringing the lower end surface of the shoulder portion F1 into contact with the outer peripheral surface 11f of the extruded perforated pipe 2 to hold down the plastic fluid material, the generation of burrs can be suppressed.

Further, in the indentation section of the main joining process, 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 the position overlapping with 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 a curve 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 a curve when viewed from above. The curve may be, for example, an arcuate locus.

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, and the temperature rise in the butt portion J1 can be expected. The pipe 2 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 in which 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 perforated pipe 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 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 perforated pipe 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 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, the second aluminum alloy of the extruded perforated pipe 2 that is frictionally agitated can flow into the gap of the butt portion J1 and the metal shortage of the butt portion J1 can be prevented.

Further, by providing the lid 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 indentation 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. 7 and 8, 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. 7, 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. 7, friction stir welding is performed from the start position SP1 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 pipe 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 closet section, the stirring pin F2 is set so that the outer peripheral surface of the stirring pin F2 and the stepped inclined surface 23b are parallel to each other when the intermediate point S1 is reached while moving the rotation tool F. The outer peripheral surface and the stepped inclined surface 23b are set so as to be in slight contact with each other. Further, the lower end surface of the shoulder portion F1 and the outer peripheral surface 11f of the extruded perforated pipe 2 are set to be in 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. 8, 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 detachment section as it is. In the departure section, as shown in FIG. 8, 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. Further, in the push-in section of the main joining step according to the second embodiment, the stirring pin F2 is gradually pushed in until the depth reaches a predetermined depth while moving the rotation tool F on the set movement route, so that the rotation tool F is moved on the set movement route L1. It is possible to prevent the rotation tool F from stopping at one point and excessive frictional heat. Further, in the detachment section of the main joining step according to the second embodiment, the rotation tool F is moved on the set movement route and the stirring pin F2 is gradually detached, so that the rotation tool F is at one point on the set movement route L1. Can be prevented from stopping and the frictional heat becoming excessive. 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 F1 Shoulder part F2 Stirring pin F3 Flat surface J1 Butt part SP1 Start position EP1 End position W1 Plasticization area

Claims (12)

A method for manufacturing a heat exchanger, which comprises 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 frictional stirring. 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 stir is provided with a shoulder portion and a stirring pin that hangs down from the center of the lower end surface of the shoulder portion, and the stirring pin has a tapered shape.
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.
The stirring pin of the rotating tool is inserted into the outer peripheral surface of the extruded perforated pipe, and the lower end surface of the shoulder portion is touched while the outer peripheral surface of the stirring pin is slightly brought into contact with the stepped inclined surface of the lid. In a state of being in contact with the outer peripheral surface of the extruded perforated pipe, while flowing the second aluminum alloy into the gap, a predetermined depth is taken along the set movement route set on the extruded perforated pipe side from the butt portion. Including the main joining step of circling around the outer peripheral surface of the extruded perforated pipe and rubbing and stirring the butt portion.
In the main joining step, after the rotating stirring pin is inserted at a start position set in a direction further away from the butt portion than 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 the desired position. In the main joining step, the rotary tool is rotated at a predetermined rotation speed to perform friction stir welding.
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 the stirring pin is moved to the set movement route while gradually reducing the rotation speed. The method for manufacturing a heat exchanger according to claim 1. A method for manufacturing a heat exchanger, which comprises an extruded perforated pipe having fins inside and a lid that seals an opening of the extruded perforated pipe, and joins the extruded perforated pipe and the lid by frictional stirring. 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 stir welding has a shoulder portion and a stirring pin that hangs down from the center of the lower end surface of the shoulder portion.
The stirring pin has a tapered shape and is tapered.
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.
The stirring pin of the rotating tool is inserted into the outer peripheral surface of the extruded perforated pipe, and the lower end surface of the shoulder portion is touched while the outer peripheral surface of the stirring pin is slightly brought into contact with the stepped inclined surface of the lid. In a state of being in contact with the outer peripheral surface of the extruded perforated pipe, while flowing the second aluminum alloy into the gap, a predetermined depth is taken along the set movement route set on the extruded perforated pipe side from the butt portion. Including the main joining step of circling around the outer peripheral surface of the extruded perforated pipe and rubbing and stirring the butt portion.
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 depth while moving in the traveling direction. How to make a switch. In the main joining step, the rotary tool is rotated at a predetermined rotation speed to perform friction stir welding.
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 the stirring pin 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 comprises an extruded perforated pipe having fins inside and a lid that seals an opening of the extruded perforated pipe, and joins the extruded perforated pipe and the lid by frictional stirring. 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 stir welding has a shoulder portion and a stirring pin that hangs down from the center of the lower end surface of the shoulder portion.
The stirring pin has a tapered shape and is tapered.
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.
The stirring pin of the rotating tool is inserted into the outer peripheral surface of the extruded perforated pipe, and the lower end surface of the shoulder portion is touched while the outer peripheral surface of the stirring pin is slightly brought into contact with the stepped inclined surface of the lid. In a state of being in contact with the outer peripheral surface of the extruded perforated pipe, while flowing the second aluminum alloy into the gap, a predetermined depth is taken along the set movement route set on the extruded perforated pipe side from the butt portion. Including the main joining step of circling around the outer peripheral surface of the extruded perforated pipe and rubbing and stirring the butt portion.
In the main joining step, the end position is set in a direction further away from the butt portion than the set movement route, and after friction stir welding with respect to the butt portion, the rotation tool is moved to the end position and the stirring is performed. A method for manufacturing a heat exchanger, which comprises gradually pulling out a pin to separate 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 pulled out 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 comprises an extruded perforated pipe having fins inside and a lid that seals an opening of the extruded perforated pipe, and joins the extruded perforated pipe and the lid by frictional stirring. 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 stir welding has a shoulder portion and a stirring pin that hangs from the center of the lower end surface of the shoulder portion.
The stirring pin has a tapered shape and is tapered.
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.
The stirring pin of the rotating tool is inserted into the outer peripheral surface of the extruded perforated pipe, and the lower end surface of the shoulder portion is touched while the outer peripheral surface of the stirring pin is slightly brought into contact with the stepped inclined surface of the lid. In a state of being in contact with the outer peripheral surface of the extruded perforated pipe, while flowing the second aluminum alloy into the gap, a predetermined depth is taken along the set movement route set on the extruded perforated pipe side from the butt portion. Including the main joining step of circling around the outer peripheral surface of the extruded perforated pipe and rubbing and stirring the butt portion.
In the main joining step, an end position is set on the set movement route, and after frictional stirring joining 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 rotating tool from the extruded perforated tube. In the main joining step, the stirring pin is rotated at a predetermined rotation speed to perform friction stir welding of the butt portion.
The method for manufacturing a heat exchanger according to claim 7, wherein when the stirring pin is pulled out 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 claim 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.

Images