JP7211342B2 - Heat exchanger manufacturing method - Google Patents

Description

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

A method of manufacturing a heat exchanger using friction stir welding has been performed. For example, Patent Document 1 discloses a heat exchanger manufacturing method in which an extruded perforated tube having a plurality of holes arranged side by side and a sealing body that seals the opening of the extruded perforated tube are joined by friction stir. disclosed.

In the conventional method of manufacturing a heat exchanger, the end surface of an extruded perforated tube made of an aluminum alloy and the stepped portion formed on the outer periphery of the lid are butted to form a butt portion, and then a rotating tool is applied to the butt portion. Friction stir welding is performed using this method.

JP 2016-74016 A

Here, a relatively simple shape such as an extruded perforated tube is formed of a wrought material of a 1000 series aluminum alloy, and the lid is formed of a cast material of a 4000 series aluminum alloy, for example. There is In this way, there is a case where a heat exchanger is manufactured by joining aluminum alloy members of different grades. In such a case, the lid generally has a higher hardness than the extruded perforated pipe. The material resistance received from the lid side increases. Therefore, it becomes difficult to stir different types of materials with the stirring pin of the rotating tool in a well-balanced manner, and there is a problem that void defects occur in the plasticized region after bonding, resulting in a decrease in bonding strength.

In addition, when inserting the agitating pin G2 into the abutting portion, the agitating pin G2 is pushed vertically to a predetermined depth, so the frictional heat at the start position of the friction agitation becomes excessive. As a result, at the start position, the metal on the lid side is likely to mix into the extruded perforated tube side, which causes a problem of joint failure.

On the other hand, when the agitation pin is pulled out from the abutting portion and separated, the agitation pin is pulled out in the vertical direction, so the frictional heat at the end position of the friction agitation becomes excessive. As a result, at the end position, the metal on the lid side is likely to be mixed into the extruded perforated tube side, which causes a problem of joint failure.

From this point of view, an object of the present invention is to provide a method for manufacturing a heat exchanger that can suitably join aluminum alloys of different materials.

In order to solve the above problems, the present invention comprises an extruded perforated tube having fins inside and a lid for sealing an opening of the extruded perforated tube, wherein the extruded perforated tube and the lid are In a method for manufacturing a heat exchanger that is joined by friction stir, the lid has a bottom and a peripheral wall rising from the peripheral edge of the bottom, and the peripheral edge of the peripheral wall has a stepped side surface and a stepped side surface from the stepped side surface. and a stepped sloped surface that slopes toward the bottom side toward the outside, and the extruded perforated tube has no fins formed at the end and the peripheral wall portion is fitted. The extruded perforated tube is made of a second aluminum alloy, the lid is made of a first aluminum alloy, and the first aluminum alloy is higher than the second aluminum alloy. The rotary tool used for friction stir includes 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 perforated extruded tube, the inner peripheral surface of the perforated extruded tube and the stepped side surface of the lid are overlapped, and the extruded perforated tube abutting step of butting the end surface of the perforated tube and the step inclined surface of the lid body to form a gap having a V-shaped cross section at the abutting portion; The outer peripheral surface of the stirring pin is slightly in contact with the step inclined surface of the lid, and the lower end surface of the shoulder portion is in contact with the outer peripheral surface of the extruded perforated tube. While the di-aluminum alloy is made to flow, the abutment portion is moved around the outer peripheral surface of the extruded perforated pipe at a predetermined depth along a set moving route set closer to the extruded perforated pipe than the abutment portion. and a main welding step of friction stirring, wherein in the main welding step, the rotating tool is inserted into a starting position set in a direction further away from the butting portion than the set movement route, and then the rotating tool While moving the center axis of rotation to a position that overlaps with the set movement route, the stirring pin is gradually pushed in until the predetermined depth is reached.

In addition, the present invention comprises an extruded perforated tube having fins inside and a lid for sealing an opening of the extruded perforated tube, and the heat treatment for joining the extruded perforated tube and the lid by friction stirring. In the method for manufacturing an exchanger, the lid has a bottom and a peripheral wall rising from the peripheral edge of the bottom, and the peripheral wall has a stepped side surface on the peripheral edge of the peripheral wall, and the bottom portion increases outward from the stepped side. and a peripheral wall stepped portion having a stepped inclined surface that slopes toward the side, and the extruded perforated pipe has a fitting portion in which the peripheral wall portion is fitted without the fins formed at the end. wherein the extruded perforated tube is made of a second aluminum alloy, the lid is made of a first aluminum alloy, and the first aluminum alloy has a higher hardness than the second aluminum alloy. The rotary tool used for friction stir includes 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, and the extrusion By inserting the peripheral wall portion of the lid into the fitting portion of the perforated tube, the inner peripheral surface of the extruded perforated tube and the stepped side surface of the lid are overlapped, and the end surface of the extruded perforated tube and the A butting step of forming a V-shaped cross-sectional gap in the abutting portion by abutting the step inclined surface of the lid body, inserting a stirring pin of the rotating rotating tool into the outer peripheral surface of the extruded perforated tube, and inserting the stirring pin The second aluminum alloy is allowed to flow into the gap while the outer peripheral surface of is slightly in contact with the step inclined surface of the lid and the lower end surface of the shoulder portion is in contact with the outer peripheral surface of the extruded perforated pipe. Meanwhile, the main joining step of friction-stirring the butt portion by making a circle around the outer peripheral surface of the extruded perforated pipe at a predetermined depth along the set movement route set on the extruded perforated pipe side of the butt portion. and, in the main joining step, inserting the agitation pin from the start position set on the set movement route, and gradually pushing the agitation pin until it reaches a predetermined depth while moving in the advancing direction. characterized by

According to this manufacturing method, the second aluminum alloy mainly on the extruded perforated tube side of the butted portion is agitated and plastically fluidized by frictional heat between the lid and the perforated extruded tube, and the lid and the perforated extruded tube are agitated at the butted portion. can be spliced. In addition, since the outer peripheral surface of the stirring pin is only slightly in contact with the cover, it is possible to minimize the mixing of the first aluminum alloy from the cover into the extruded perforated tube. As a result, mainly the second aluminum alloy on the extruded perforated tube side is friction-stirred at the butted 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 to hold down the plastic flow material, it is possible to suppress the occurrence of burrs. Further, by gradually pushing the stirring pin until a predetermined depth is reached while moving the rotating tool to a position overlapping the set movement route, it is possible to prevent frictional heat from becoming excessive on the set movement route. Further, by gradually pushing the stirring pin until a predetermined depth is reached while moving the rotary tool along the set movement route, it is possible to prevent excessive frictional heat at one point on the set movement route. As a result, it is possible to prevent the first aluminum alloy of the lid from entering the extruded perforated tube side on the set movement route.

Further, in the present invention, in the main welding step, friction stir is performed by rotating the rotating tool at a predetermined rotation speed, and when inserting the stirring pin in the main welding step, the rotation speed is higher than the predetermined rotation speed. It is preferable to insert the agitating pin while rotating it at a high speed and move it to the set movement route while gradually decreasing the rotational speed.

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

In addition, the present invention comprises an extruded perforated tube having fins inside and a lid for sealing an opening of the extruded perforated tube, and the heat treatment for joining the extruded perforated tube and the lid by friction stirring. In the method for manufacturing an exchanger, the lid has a bottom and a peripheral wall rising from the peripheral edge of the bottom, and the peripheral wall has a stepped side surface on the peripheral edge of the peripheral wall, and the bottom portion increases outward from the stepped side. and a peripheral wall stepped portion having a stepped inclined surface that slopes toward the side, and the extruded perforated pipe has a fitting portion in which the peripheral wall portion is fitted without the fins formed at the end. wherein the extruded perforated tube is made of a second aluminum alloy, the lid is made of a first aluminum alloy, and the first aluminum alloy has a higher hardness than the second aluminum alloy. The rotary tool used for friction stir includes 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, and the extrusion By inserting the peripheral wall portion of the lid into the fitting portion of the perforated tube, the inner peripheral surface of the extruded perforated tube and the stepped side surface of the lid are overlapped, and the end surface of the extruded perforated tube and the A butting step of forming a V-shaped cross-sectional gap in the abutting portion by abutting the step inclined surface of the lid body, inserting a stirring pin of the rotating rotating tool into the outer peripheral surface of the extruded perforated tube, and inserting the stirring pin The second aluminum alloy is allowed to flow into the gap while the outer peripheral surface of is slightly in contact with the step inclined surface of the lid and the lower end surface of the shoulder portion is in contact with the outer peripheral surface of the extruded perforated pipe. Meanwhile, the main joining step of friction-stirring the butt portion by making a circle around the outer peripheral surface of the extruded perforated pipe at a predetermined depth along the set movement route set on the extruded perforated pipe side of the butt portion. and, in the main welding step, an end position is set in a direction further away from the butt part than the set movement route, and after friction stir welding to the butt part, the rotating tool is moved to the end position The stirring pin is gradually pulled out while being moved, and the rotary tool is separated from the extrusion perforated tube at the end position.

In addition, the present invention comprises an extruded perforated tube having fins inside and a lid for sealing an opening of the extruded perforated tube, and the heat treatment for joining the extruded perforated tube and the lid by friction stirring. In the method for manufacturing an exchanger, the lid has a bottom and a peripheral wall rising from the peripheral edge of the bottom, and the peripheral wall has a stepped side surface on the peripheral edge of the peripheral wall, and the bottom portion increases outward from the stepped side. and a peripheral wall stepped portion having a stepped inclined surface that slopes toward the side, and the extruded perforated pipe has a fitting portion in which the peripheral wall portion is fitted without the fins formed at the end. wherein the extruded perforated tube is made of a second aluminum alloy, the lid is made of a first aluminum alloy, and the first aluminum alloy has a higher hardness than the second aluminum alloy. The rotary tool used for friction stir includes 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, and the extrusion By inserting the peripheral wall portion of the lid into the fitting portion of the perforated tube, the inner peripheral surface of the extruded perforated tube and the stepped side surface of the lid are overlapped, and the end surface of the extruded perforated tube and the A butting step of forming a V-shaped cross-sectional gap in the abutting portion by abutting the step inclined surface of the lid body, inserting a stirring pin of the rotating rotating tool into the outer peripheral surface of the extruded perforated tube, and inserting the stirring pin The second aluminum alloy is allowed to flow into the gap while the outer peripheral surface of is slightly in contact with the step inclined surface of the lid and the lower end surface of the shoulder portion is in contact with the outer peripheral surface of the extruded perforated pipe. Meanwhile, the main joining step of friction-stirring the butt portion by making a circle around the outer peripheral surface of the extruded perforated pipe at a predetermined depth along the set movement route set on the extruded perforated pipe side of the butt portion. and, in the main welding step, an end position is set on the set moving route, and after friction stir welding to the butted portion, the agitation pin is gradually moved while moving the rotating tool to the end position. The rotary tool is separated from the extruded perforated tube at the end position by pulling it out.

According to this manufacturing method, the second aluminum alloy mainly on the extruded perforated tube side of the butted portion is agitated and plastically fluidized by frictional heat between the lid and the perforated extruded tube, and the lid and the perforated extruded tube are agitated at the butted portion. can be spliced. In addition, since the outer peripheral surface of the stirring pin is only slightly in contact with the cover, it is possible to minimize the mixing of the first aluminum alloy from the cover into the extruded perforated tube. As a result, mainly the second aluminum alloy on the extruded perforated tube side is friction-stirred at the butted 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 to hold down the plastic flow material, it is possible to suppress the occurrence of burrs. Further, by gradually withdrawing the stirring pin while moving the rotary tool toward the end position, it is possible to prevent excessive frictional heat on the set movement route. Further, by gradually withdrawing the stirring pin until a predetermined depth is reached while moving the rotary tool along the set movement route, it is possible to prevent excessive frictional heat at one point on the set movement route. As a result, it is possible to prevent the first aluminum alloy of the lid from entering the extruded perforated tube side on the set movement route.

Further, in the main welding step, the agitating pin is rotated at a predetermined rotational speed to perform friction stir welding of the butted portion. It is preferable to move to the end position while increasing the rotational speed.

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

Moreover, in the butting step, the extruded perforated pipe and the lid are preferably formed so that the outer peripheral surface of the extruded perforated pipe is positioned outside the outer peripheral surface of the lid.

According to this manufacturing method, it is possible to prevent shortage of metal in the joint.

Further, it is preferable to set the rotating direction and advancing direction of the rotating tool such that the butting portion side is the advancing side.

According to this manufacturing method, the friction stir at the butt portion side is promoted, and more suitable joining can be achieved.

Further, in the main joining step, it is preferable that the tip of the stirring pin is passed through the stepped side surface of the lid body and then made to circle around the outer peripheral surface of the extruded perforated tube to friction stir the butted portion.

According to this manufacturing method, the lid and the extruded perforated pipe can be more suitably joined.

Moreover, 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 heat exchanger manufacturing method of the present invention, aluminum alloys of different types can be suitably joined.

1 is a side view of a rotary tool according to an embodiment of the invention; FIG. It is an exploded perspective view showing a heat exchanger concerning a first embodiment of the present invention. It is sectional drawing which shows the butt|matching process of the manufacturing method of the heat exchanger which concerns on 1st embodiment. FIG. 4 is a schematic diagram showing the starting position of the main joining step in the method for manufacturing the heat exchanger according to the first embodiment; FIG. 4 is a cross-sectional view showing the main joining step of the method for manufacturing the heat exchanger according to the first embodiment; FIG. 4 is a schematic diagram showing the end position of the main joining step in the method for manufacturing the heat exchanger according to the first embodiment; FIG. 5 is a schematic diagram showing the starting position of the main joining step in the method for manufacturing a heat exchanger according to the second embodiment of the present invention; FIG. 5 is a schematic diagram showing the end position of the main joining step in the method for manufacturing a heat exchanger according to the second embodiment of the present invention;

Embodiments of the present invention will be described with reference to the drawings as appropriate. First, the rotary tool used in the joining method according to this embodiment will be described. A rotating tool is a tool used for friction stir welding. As shown in FIG. 1, the rotary tool F is made of tool steel, for example, and comprises 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 cylindrical 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 to the outside.

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 agitating pin F2 tapers away from the shoulder F1. A spiral groove is engraved on the outer peripheral surface of the stirring pin F2. In this embodiment, in order to rotate the rotating tool F to the right, the spiral groove is engraved counterclockwise from the proximal end to the distal end.

When the rotating tool F is rotated counterclockwise, the spiral groove is engraved clockwise from the base end toward the tip end. In this way, the metal that has been 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, it is possible to reduce the amount of metal that overflows from the metal members to be joined (the perforated extruded pipe 2 and the lid 3).

[First embodiment]
Embodiments of the present invention will be described with reference to the drawings as appropriate. A heat exchanger 1 according to the first embodiment, as shown in FIG. The heat exchanger 1 is a device that circulates a fluid inside to cool a heat generating element arranged therein. The extruded perforated pipe 2 and the lid bodies 3, 3 are integrated by friction stir welding.

The extruded perforated tube 2 is mainly composed of a body portion 11 and a plurality of fins 12 . The extruded perforated tube 2 is formed mainly containing a second aluminum alloy in this embodiment. The second aluminum alloy is made of, for example, an aluminum alloy wrought material such as JIS A1050, A1100, A6063. The extruded perforated tube 2 is an extruded profile made of a second aluminum alloy.

The body portion 11 has a tubular shape. The side portions 11a and 11b of the main body portion 11 are curved so as to protrude outward (outward in the width direction of the main body portion 11). The substrate portions 11c and 11d of the body portion 11 are flat and face each other in parallel. That is, the cross section of the main body portion 11 has an oval shape. The fins 12 are perpendicular to the substrate portions 11c and 11d. The fins 12 extend in the direction in which the main body 11 is pushed out and are formed parallel to each other. Between adjacent fins 12, a plurality of holes 13 having a rectangular cross section through which fluid flows are formed.

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

The lids 3 , 3 are members for sealing openings at both ends of the extruded perforated tube 2 . The lids 3, 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-like member having an oblong 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 portion of the bottom portion 21 . The peripheral wall portion 22 is formed in an elongated frame shape along the shape of the bottom portion 21 . A concave header channel 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 that can be friction-stirred, but in the present embodiment, it mainly contains a first aluminum alloy. The first aluminum alloy is a harder material 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. In this specification, hardness refers to Brinell hardness, which can be measured by a method according to JIS Z 2243.

As shown in FIG. 3, the peripheral wall portion 22 has a peripheral wall stepped portion 23 formed at the outer peripheral edge thereof, the peripheral wall stepped portion 23 including a stepped side surface 23a and a stepped inclined surface 23b rising from the stepped side surface 23a. The peripheral wall stepped portion 23 is formed over the entire circumferential direction. The stepped side surface 23a is parallel to the extrusion direction. The stepped inclined surface 23b is inclined so as to approach the bottom portion 21 from the stepped side surface 23a toward the outside (outer side in the width direction of the main body portion 11). In other words, the step sloped surface 23b slopes away from the 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 of the step inclined surface 23b with respect to the vertical plane (see FIG. 3) is the same as the inclination angle α of the stirring pin F2 with respect to the rotation center axis Z (see FIG. 1).

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. It is set so that the outer peripheral surface 11f of the extruded perforated tube 2 is on the outside. In other words, the height (thickness) dimension of the end surface 11e of the extruded perforated tube 2 is set to be larger than the height dimension of the step inclined surface 23b.

Next, a method for manufacturing the heat exchanger according to this embodiment will be described. In the method for manufacturing a heat exchanger according to this embodiment, a preparatory step, a butting step, and a final joining step are performed.

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

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

4 and 5, the main welding step is a step of friction stir welding the butted portion J1 using a rotary tool F. FIG. First, a “set movement route L1” (one-dot chain line) is set at a position away from the cover 3 with respect to the abutting portion J1. The set movement route L1 is a movement route of the rotary tool F necessary for joining the butt portion J1 in the main joining process described later. The set travel route L1 will be described later in detail.

As shown in FIG. 4, in the main joining step, there are a push-in section from the starting position SP1 to the intermediate point S1, a main section from the intermediate point S1 on the set movement route L1 to the intermediate point S2, and an intermediate point S2. 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 in the main body portion 11 of the perforated extruded tube 2 at a position away from the abutting portion J1 with respect to the set movement route L1. In this 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 pushing section of the main joining step, friction stir is performed from the start position SP1 to the intermediate point S1. In the push-in section, the rotation center axis Z is perpendicular to the outer peripheral surface 11f of the main body 11, and the rotating tool F (stirring pin F2) rotated to the right is inserted into the starting position SP1 and 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" at least until reaching the intermediate point S1. In other words, the rotating tool F is gradually lowered while being moved along the set movement route L1 without remaining in one place. When the rotating tool F reaches the intermediate point S1, the process proceeds directly to the main section. Here, the "predetermined depth" refers to the depth to 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 rotating 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 made 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, due to contact between at least 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 perforated extruded tube 2 side. Further, the insertion depth is set so that the flat surface F3 of the stirring pin F2 penetrates the stepped 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. In addition, it is preferable that the lower end surface of the shoulder portion F<b>1 does not contact the outer peripheral surface 22 b of the peripheral wall portion 22 . The rotation center axis Z of the rotating tool F and the outer peripheral surface 11f of the body portion 11 are set to be perpendicular to each other, and the rotating tool F is relatively moved along the abutting portion J1 while maintaining these.

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

The set movement route L1, as shown in FIG. 5, indicates 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 agitation pin F2 are parallel to each other in the circumferential direction of the butted portion J1 and are slightly in contact with each other. In this section, the rotating tool F is moved so that the center of the flat surface F3 overlaps the set moving route L1 when the rotating tool F is viewed from above. The "predetermined depth" of the stirring pin F2 may be appropriately set, but in this embodiment, the flat surface F3 of the rotary tool F is inserted to a position where it penetrates the stepped side surface 23a. As a result, the butted portion J2 can also be reliably joined.

If the outer peripheral surface of the stirring pin F2 and the step inclined surface 23b are set so as not to come into contact with each other, the bonding strength of the butted portion J1 is reduced. On the other hand, if the contact margin N of the step 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 perforated extruded tube 2 side, resulting in poor bonding.

As shown in FIG. 6, when the rotary tool F is made to make one turn and the stirring pin F2 reaches the intermediate point S2, the process proceeds to the detachment section. In the detachment section, the stirring pin F2 is gradually pulled out (raised) from the intermediate point S2 to the end position EP1, and the agitation pin F2 is detached from the extruded perforated tube 2 at the end position EP1. In other words, the rotating tool F is gradually pulled out while being moved to the end position EP1 without remaining in one place. The end position EP1 is set in the body portion 11 of the perforated extruded tube 2 at a position separated from the abutting portion J1 with respect to the set movement route L1. In this 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 be an obtuse angle. A plasticized region W1 is formed in the movement locus of the rotating tool F. As shown in FIG. After the friction stir welding of the extruded perforated pipe 2 and the cover 3 on the one end side is completed as described above, friction stir welding of the extruded perforated pipe 2 and the cover 3 on the other end is performed in the same manner.

According to the heat exchanger manufacturing method of the present embodiment described above, the frictional heat between the perforated extruded pipe 2 and the stirring pin F2 stirs mainly the second aluminum alloy on the side of the perforated extruded pipe 2 of the butted portion J1, resulting in plasticity. Fluidized, the end surface 11e of the extruded perforated tube 2 and the step inclined surface 23b of the lid 3 can be joined at the abutting portion J1.

In addition, since the outer peripheral surface of the stirring pin F2 is only slightly in contact with the step inclined surface 23b, mixing of the first aluminum alloy from the lid 3 into the extruded perforated tube 2 can be minimized. As a result, mainly the second aluminum alloy on the extruded perforated pipe 2 side is friction-stirred at the butted portion J1, so that a decrease in joint strength can be suppressed. That is, in the main joining step, the imbalance in 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. In addition, since the outer peripheral surface of the stirring pin F2 and the step inclined surface 23b of the lid 3 are set parallel, the plastic flow material is friction-stirred in a well-balanced manner, and a decrease in bonding 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 tube 2 to hold down the plastic flow material, it is possible to suppress the occurrence of burrs.

In addition, in the pushing section of the main joining step, the rotating tool F is moved from the starting position SP1 to a position overlapping the set movement route L1, and the stirring pin F2 is gradually pushed in until the set movement route L1 reaches a predetermined depth. It is possible to prevent the movement of the rotary tool F from stopping on L1 and the frictional heat from becoming excessive.
Similarly, in the detachment section of the main welding process, while moving the rotating tool F from the set movement route L1 to the end position EP1, the agitation pin F2 is gradually pulled out from a predetermined depth to be detached, thereby moving the set movement route L1. It is possible to prevent the movement of the rotary tool F from stopping at , and the frictional heat from becoming excessive.

As a result, it is possible to prevent the frictional heat from becoming excessively large on the set movement route L1 and the first aluminum alloy from being excessively mixed into the extruded perforated tube 2 from the lid 3, resulting in poor bonding.

In addition, 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 between the start position SP1 and the set movement route L1 and the angle formed between the end position EP1 and the set movement route L1 are By setting the obtuse angle, the movement speed of the rotating tool F does not decrease at the intermediate points S1 and S2, and the transition to the main section or the detachment section can be performed smoothly. As a result, it is possible to prevent frictional heat from becoming excessive due to the rotation tool F stopping or moving at a reduced speed on the set movement route L1. Note that the rotary tool F may be moved from the start position SP1 to the set movement route L1 so that the trajectory of the rotary tool F draws a curve when viewed from above. Similarly, the rotary tool F may be moved from the set movement route L1 to the end position EP1 so that the trajectory of the rotary tool F draws a curve when viewed from above. A curve may be, for example, an arc-shaped locus.

In addition, in the main joining process of the present embodiment, the rotation direction and the traveling direction of the rotary tool F may be appropriately set. The direction of rotation and the direction of movement of the rotating tool F were set so that the butted portion J1 side) was on the shear side and the extruded perforated tube 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 at the butt portion J1 can be expected, and the lid 3 and the extruded pores are expected to rise at the butt portion J1. The tube 2 can be joined more reliably.

The shear side (Advancing side) means the side where the relative velocity of the outer circumference of the rotating tool with respect to the part to be welded is the sum of the tangential velocity at the outer circumference of the rotating tool and the moving velocity. . 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 parts to be welded becomes low due to the rotation of the rotating tool in the direction opposite to the moving direction of the rotating tool.

Moreover, the first aluminum alloy of the lid 3 is a material with higher hardness than the second aluminum alloy of the extruded perforated tube 2 . Thereby, the durability of the heat exchanger 1 can be improved. Moreover, it is preferable that the first aluminum alloy of the lid body 3 is a cast aluminum alloy material, and the second aluminum alloy of the extruded perforated tube 2 is a wrought aluminum alloy material. By using, for example, an Al--Si--Cu-based aluminum alloy cast material such as JISH5302 ADC12 as the first aluminum alloy, the castability, strength, machinability, etc. of the lid 3 can be enhanced. Further, by using, for example, JIS A1000 series or A6000 series as the second aluminum alloy, the workability and thermal conductivity of the extruded perforated pipe 2 can be enhanced.

In addition, in the main joining step, the entire circumference of the butted portion J1 can be friction stir welded, so that the airtightness and watertightness of the heat exchanger can be improved. Also, at the end portion of the main joining process, the rotating tool F is made to head toward the end position EP1 after completely passing the intermediate point S1. That is, by overlapping the ends of the plasticized regions W1 formed by the main joining step, airtightness and watertightness can be further enhanced.

Further, in this embodiment, the outer peripheral surface 11f of the perforated extruded pipe 2 is set to be outside the outer peripheral surface 22b of the peripheral wall portion 22 after the butting step is performed. As a result, the second aluminum alloy of the perforated extruded tube 2 to be friction-stirred can be caused to flow into the clearance of the butt portion J1, and metal shortage at the butt portion J1 can be prevented.

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

In addition, in the main joining step, the rotating speed of the rotating tool F may be constant, but may be varied. In the pressing section of the main joining step, if the rotational speed of the rotating tool F at the start position SP1 is V1 and the rotational speed of the rotating tool F in this section is V2, V1>V2 may be satisfied. The rotation speed V2 is a preset constant rotation speed on the set movement route L1. In other words, at the start position SP1, the rotation speed may be set high, and the rotation speed may be gradually reduced in the push-in interval to shift to the main interval.

Further, in the detachment section of the first main welding step, V3>V2 may be satisfied, where V2 is the rotational speed of the rotating tool F in this section and V3 is the rotational speed of the rotating tool F when detached at the end position EP1. That is, after shifting to the detachment section, the rotary tool F may be detached from the extruded perforated tube 2 while gradually increasing the rotational speed toward the end position EP1. When the rotating tool F is pushed into the extruded perforated tube 2 or removed from the extruded perforated tube 2, by setting as described above, the small pressing force in the pushing section or the removing section can be compensated for by the rotation speed. Therefore, friction stirring can be preferably performed.

[Second embodiment]
Next, a method for manufacturing a heat exchanger according to the second embodiment of the invention will be described. In the second embodiment, as shown in FIGS. 7 and 8, the positions of the start position SP1, intermediate points S1 and S2, and 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 description will focus on the parts that are different from the first embodiment.

In manufacturing the heat exchanger according to the second embodiment, a preparation step, a butting step, and a final joining step are performed. The preparation process and matching process are the same as in the first embodiment.

In the main joining step, as shown in FIG. 7, the starting position SP1 is set on the set movement route L1. In the main joining process, there is a push-in section from the starting position SP1 to the intermediate point S1, a main section from the intermediate point S1 to the intermediate point S2 around the set movement route L1, and a separation from the intermediate point S2 to the end position EP1. Friction stir the three sections of the section in succession.

In the push-in section, as shown in FIG. 7, friction stir is performed from the start position SP1 to the intermediate point S1. In the push-in section, while the central axis of rotation Z is perpendicular to the outer peripheral surface 11f of the extruded perforated tube 2, the stirring pin F2 rotated to the right is inserted into the starting position SP1 and 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" at least until reaching the intermediate point S1.

In the push-in section, while moving the rotary tool F, when reaching the intermediate point S1, the outer peripheral surface of the stirring pin F2 and the step inclined surface 23b are set to be parallel to each other. The outer peripheral surface and the step inclined surface 23b are set so as to be slightly in contact with each other. Also, the lower end surface of the shoulder portion F1 and the outer peripheral surface 11f of the extruded perforated tube 2 are set to contact each other. Then, while maintaining this state, the process shifts to friction stir welding in this section. The setting of the contact margin (offset amount) N between the outer peripheral surface of the stirring pin F2 and the step inclined surface 23b and the set movement route L1 are the same as in the first embodiment.

As shown in FIG. 8, when the rotary tool F is made to make one turn and the stirring pin F2 reaches the intermediate point S2, the process proceeds to the detachment section. In the separation section, as shown in FIG. 8, the agitation pin F2 is gradually pulled out (moved upward) from the intermediate point S2 to the end position EP1, and the end set on the set movement route L1 is reached. The stirring pin F2 is removed from the extruded perforated tube 2 at the position EP1.

The heat exchanger manufacturing method according to the second embodiment described above can also achieve substantially the same effects as those of the first embodiment. Furthermore, in the pushing section of the main joining process according to the second embodiment, by gradually pushing the stirring pin F2 until a predetermined depth is reached while moving the rotating tool F on the set movement route L1, It is possible to prevent the rotary tool F from stopping at one point and causing excessive frictional heat. Further, in the detachment section of the main joining process according to the second embodiment, by gradually detaching the stirring pin F2 while moving the rotating tool F on the set movement route, the rotating tool F is moved at one point on the set movement route L1. can stop and prevent frictional heat from 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.

REFERENCE SIGNS LIST 1 heat exchanger 2 extruded perforated tube 3 lid F rotating tool F1 shoulder F2 stirring pin F3 flat surface J1 butt part SP1 start position EP1 end position W1 plasticizing region

Claims (12)

A method for manufacturing a heat exchanger comprising an extruded perforated tube having fins inside and a lid sealing an opening of the extruded perforated tube, wherein the extruded perforated tube and the lid are joined by friction stir. There is
The lid has a bottom and a peripheral wall rising from the peripheral edge of the bottom, and has a stepped side surface on the peripheral edge of the peripheral wall, and a stepped side surface that slopes toward the bottom side toward the outside from the stepped side surface. 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 and the peripheral wall portion is fitted,
The extruded perforated tube is made of a second aluminum alloy, the lid is made of a first aluminum alloy, and the first aluminum alloy is a material having higher hardness than the second aluminum alloy,
A rotary tool used for friction stir includes 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 perforated extruded tube, the inner peripheral surface of the perforated extruded tube and the stepped side surface of the lid are overlapped, and the end surface of the perforated extruded tube is formed. and a butting step of butting the step inclined surface of the lid body to form a gap having a V-shaped cross section in the butting portion;
The stirring pin of the rotating rotary tool is inserted into the outer peripheral surface of the extruded perforated tube, and while the outer peripheral surface of the stirring pin is slightly in contact with the step inclined surface of the lid, the lower end surface of the shoulder portion is While being in contact with the outer peripheral surface of the extruded perforated tube, the second aluminum alloy is allowed to flow into the gap, and is moved to a predetermined depth along a set movement route set on the extruded perforated tube side of the abutting portion. and a main joining step of friction-stirring the butt portion by making a circle around the outer peripheral surface of the extruded perforated pipe,
In the main joining step, after inserting the rotating stirring pin into a starting position set in a direction further away from the butting portion than the set movement route, the rotation center axis of the rotating tool overlaps the set movement route. A method of manufacturing a heat exchanger, wherein the agitating pin is gradually pushed in until the predetermined depth is reached while moving to a position where the agitation pin reaches the predetermined depth. In the main welding step, friction stir is performed by rotating the rotating tool at a predetermined rotational speed,
When inserting the agitation pin in the main joining step, insert the agitation pin while rotating it at a speed higher than the predetermined rotational speed, and move it to the set movement route while gradually decreasing the rotational speed. The method for manufacturing a heat exchanger according to claim 1, characterized by: A method for manufacturing a heat exchanger comprising an extruded perforated tube having fins inside and a lid sealing an opening of the extruded perforated tube, wherein the extruded perforated tube and the lid are joined by friction stir. There is
The lid has a bottom and a peripheral wall rising from the peripheral edge of the bottom, and has a stepped side surface on the peripheral edge of the peripheral wall, and a stepped side surface that slopes toward the bottom side toward the outside from the stepped side surface. 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 and the peripheral wall portion is fitted,
The extruded perforated tube is made of a second aluminum alloy, the lid is made of a first aluminum alloy, and the first aluminum alloy is a material having higher hardness than the second aluminum alloy,
A rotating tool used for friction stir includes a shoulder portion, and a stirring pin hanging down from the center of the lower end surface of the shoulder portion,
The stirring pin has a tapered shape,
By inserting the peripheral wall portion of the lid into the fitting portion of the perforated extruded tube, the inner peripheral surface of the perforated extruded tube and the stepped side surface of the lid are overlapped, and the end surface of the perforated extruded tube is formed. and a butting step of butting the step inclined surface of the lid body to form a gap having a V-shaped cross section at the butting portion;
The stirring pin of the rotating rotary tool is inserted into the outer peripheral surface of the extruded perforated tube, and while the outer peripheral surface of the stirring pin is slightly in contact with the step inclined surface of the lid, the lower end surface of the shoulder portion is While being in contact with the outer peripheral surface of the extruded perforated tube, the second aluminum alloy is allowed to flow into the gap, and is moved to a predetermined depth along a set movement route set on the extruded perforated tube side of the abutting portion. and a main joining step of friction-stirring the butt portion by making a circle around the outer peripheral surface of the extruded perforated pipe,
In the main joining step, the agitation pin is inserted from a start position set on the set movement route, and the agitation pin is gradually pushed in until a predetermined depth is reached while moving in the traveling direction. A method for manufacturing an exchanger. In the main welding step, friction stir is performed by rotating the rotating tool at a predetermined rotational speed,
When inserting the agitation pin in the main joining step, insert the agitation pin while rotating it at a speed higher than the predetermined rotational speed, and move it to the set movement route while gradually decreasing the rotational speed. The method for manufacturing a heat exchanger according to claim 3, characterized by: A method for manufacturing a heat exchanger comprising an extruded perforated tube having fins inside and a lid sealing an opening of the extruded perforated tube, wherein the extruded perforated tube and the lid are joined by friction stir. There is
The lid has a bottom and a peripheral wall rising from the peripheral edge of the bottom, and has a stepped side surface on the peripheral edge of the peripheral wall, and a stepped side surface that slopes toward the bottom side toward the outside from the stepped side surface. 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 and the peripheral wall portion is fitted,
The extruded perforated tube is made of a second aluminum alloy, the lid is made of a first aluminum alloy, and the first aluminum alloy is a material having higher hardness than the second aluminum alloy,
A rotating tool used for friction stir includes a shoulder portion, and a stirring pin hanging down from the center of the lower end surface of the shoulder portion,
The stirring pin has a tapered shape,
By inserting the peripheral wall portion of the lid into the fitting portion of the perforated extruded tube, the inner peripheral surface of the perforated extruded tube and the stepped side surface of the lid are overlapped, and the end surface of the perforated extruded tube is formed. and a butting step of butting the step inclined surface of the lid body to form a gap having a V-shaped cross section at the butting portion;
The stirring pin of the rotating rotary tool is inserted into the outer peripheral surface of the extruded perforated tube, and while the outer peripheral surface of the stirring pin is slightly in contact with the step inclined surface of the lid, the lower end surface of the shoulder portion is While being in contact with the outer peripheral surface of the extruded perforated tube, the second aluminum alloy is allowed to flow into the gap, and is moved to a predetermined depth along a set movement route set on the extruded perforated tube side of the abutting portion. and a main joining step of friction-stirring the butt portion by making a circle around the outer peripheral surface of the extruded perforated pipe,
In the main welding step, an end position is set in a direction further away from the butt portion than the set moving route, and after friction stir welding to the butt portion, the rotating tool is moved to the end position while stirring. A method of manufacturing a heat exchanger, wherein the pin is gradually pulled out to separate the rotary tool from the extruded perforated tube at the end position. In the main joining step, friction stir is performed by rotating the stir pin at a predetermined rotational speed,
6. The method of manufacturing a heat exchanger according to claim 5, wherein when the stirring pin is pulled out in the main joining step, it is moved to the end position while gradually increasing the rotation speed from the predetermined rotation speed. A method for manufacturing a heat exchanger comprising an extruded perforated tube having fins inside and a lid sealing an opening of the extruded perforated tube, wherein the extruded perforated tube and the lid are joined by friction stir. There is
The lid has a bottom and a peripheral wall rising from the peripheral edge of the bottom, and has a stepped side surface on the peripheral edge of the peripheral wall, and a stepped side surface that slopes toward the bottom side toward the outside from the stepped side surface. 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 and the peripheral wall portion is fitted,
The extruded perforated tube is made of a second aluminum alloy, the lid is made of a first aluminum alloy, and the first aluminum alloy is a material having higher hardness than the second aluminum alloy,
A rotating tool used for friction stir includes a shoulder portion, and a stirring pin hanging down from the center of the lower end surface of the shoulder portion,
The stirring pin has a tapered shape,
By inserting the peripheral wall portion of the lid into the fitting portion of the perforated extruded tube, the inner peripheral surface of the perforated extruded tube and the stepped side surface of the lid are overlapped, and the end surface of the perforated extruded tube is formed. and a butting step of butting the step inclined surface of the lid body to form a gap having a V-shaped cross section in the butting portion;
The stirring pin of the rotating rotary tool is inserted into the outer peripheral surface of the extruded perforated tube, and while the outer peripheral surface of the stirring pin is slightly in contact with the step inclined surface of the lid, the lower end surface of the shoulder portion is While being in contact with the outer peripheral surface of the extruded perforated tube, the second aluminum alloy is allowed to flow into the gap, and is moved to a predetermined depth along a set movement route set on the extruded perforated tube side of the abutting portion. and a main joining step of friction-stirring the butt portion by making a circle around the outer peripheral surface of the extruded perforated pipe,
In the main welding step, an end position is set on the set moving route, and after the friction stir welding of the butted portion, the rotating tool is moved to the end position and the stirring pin is gradually pulled out to the end position. 3. A method for manufacturing a heat exchanger, wherein the rotating tool is separated from the extruded perforated tube in . In the main welding step, the agitation pins are rotated at a predetermined rotational speed to perform friction stir welding of the butt portions,
8. The method of manufacturing a heat exchanger according to claim 7, wherein when the stirring pin is pulled out in the main joining step, it is moved to the end position while gradually increasing the rotation speed from the predetermined rotation speed. 1. The extruded perforated pipe and the lid are formed in the butting step so that the outer peripheral surface of the extruded perforated pipe is positioned outside the outer peripheral surface of the lid. A method for manufacturing a heat exchanger according to claim 8 . 10. The method of manufacturing a heat exchanger according to any one of claims 1 to 9, wherein the rotating direction and advancing direction of the rotating tool are set so that the butting portion side is the advancing side. In the main joining step, the tip of the stirring pin penetrates the stepped side surface of the lid body and is made to go around the outer peripheral surface of the extruded perforated tube to friction stir the butted portion. A method for manufacturing a heat exchanger according to any one of claims 1 to 10. 12. The method of manufacturing a heat exchanger according to claim 1, wherein said first aluminum alloy is made of cast material, and said second aluminum alloy is made of wrought material.

Images