[go: up one dir, main page]
More Web Proxy on the site http://driver.im/

JP2015123498A - Tube expansion plug - Google Patents

Tube expansion plug Download PDF

Info

Publication number
JP2015123498A
JP2015123498A JP2013272103A JP2013272103A JP2015123498A JP 2015123498 A JP2015123498 A JP 2015123498A JP 2013272103 A JP2013272103 A JP 2013272103A JP 2013272103 A JP2013272103 A JP 2013272103A JP 2015123498 A JP2015123498 A JP 2015123498A
Authority
JP
Japan
Prior art keywords
tube
heat transfer
expansion
transfer tube
diameter
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP2013272103A
Other languages
Japanese (ja)
Other versions
JP6238063B2 (en
Inventor
宗尚 高橋
Munehisa Takahashi
宗尚 高橋
敬治 天野
Takaharu Amano
敬治 天野
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
MA Aluminum Corp
Original Assignee
Mitsubishi Aluminum Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mitsubishi Aluminum Co Ltd filed Critical Mitsubishi Aluminum Co Ltd
Priority to JP2013272103A priority Critical patent/JP6238063B2/en
Publication of JP2015123498A publication Critical patent/JP2015123498A/en
Application granted granted Critical
Publication of JP6238063B2 publication Critical patent/JP6238063B2/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Landscapes

  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)

Abstract

PROBLEM TO BE SOLVED: To provide a tube expansion plug capable of suppressing at tube expansion the buckling of a heat-transfer tube and also collapse of internal fins.SOLUTION: A tube expansion plug 1 is inserted into a heat transfer tube the inner peripheral surface of which has a plurality of inner fins formed, in order that the heat transfer tube is inserted into an insertion hole which is formed in a plurality of radiation fins provided in parallel at a predetermined interval, and the heat transfer tube is expanded to be allowed to closely contact the radiation fins. The tube expansion plug has a shank and a head part 3 formed on a tip side of the shank. The head part is cross-sectionally nearly circular in such a manner that the tip part 3a of the cross section is becoming gradually larger in diameter toward the maximum diameter part 3c, and a smoothly connected preliminary expansion part 6A and a primary expansion part 6B are provided between the tip part and the maximum diameter part. The preliminary expansion part connects from the tip part smaller in diameter than the smallest inner diameter of the heat transfer tube to the preliminary expansion termination part larger in diameter than the smallest inner diameter with a curvature radius of 5 mm or more and 7.9 mm or less. The primary expansion part connects from the preliminary expansion termination part 3b to the maximum diameter part 3c with a curvature radius of 20.1 mm or more and 30 mm or less.

Description

本発明は、拡管プラグに関するものである。   The present invention relates to a tube expansion plug.

一般に空調機や冷凍機のフィンチューブ式の熱交換器には冷媒を流すための伝熱管が使用されている。この伝熱管として、管内に微細なフィン(内面フィン)を形成した伝熱管を使用することで、従来の平滑管と比較して管内伝熱特性が飛躍的に向上することが知られている。   In general, heat transfer tubes for flowing refrigerant are used in fin tube heat exchangers of air conditioners and refrigerators. As this heat transfer tube, it is known that by using a heat transfer tube in which fine fins (internal fins) are formed in the tube, the heat transfer characteristics in the tube are dramatically improved as compared with the conventional smooth tube.

このような伝熱管を使用して熱交換器を製造する際には、まず、伝熱管を挿通するための孔が予め形成された例えばアルミニウム合金製の多数の放熱フィンを、伝熱管の長さ方向に沿って所定のピッチで重なるように並べる。次に、伝熱管を前記各放熱フィンの孔内に挿通する。さらに、伝熱管内に拡管プラグを押込み伝熱管を拡管し、伝熱管の外径を放熱フィンの孔径より大きくする。これによって伝熱管の外周と放熱フィンの孔の内周面とを密着させる。   When manufacturing a heat exchanger using such a heat transfer tube, first, a number of heat radiation fins made of, for example, an aluminum alloy in which holes for inserting the heat transfer tube are formed in advance are used. Arrange so as to overlap at a predetermined pitch along the direction. Next, the heat transfer tubes are inserted into the holes of the respective radiation fins. Furthermore, a tube expansion plug is pushed into the heat transfer tube, the heat transfer tube is expanded, and the outer diameter of the heat transfer tube is made larger than the hole diameter of the radiation fin. As a result, the outer periphery of the heat transfer tube and the inner peripheral surface of the hole of the radiating fin are brought into close contact with each other.

拡管プラグを押し込み伝熱管を拡管する工程(拡管工程)で、伝熱管の内面フィンが倒れてしまうことがある。内面フィンに倒れが生じると伝熱管を所定の外径になるまで管を拡管できず伝熱管とプレートフィンとの間の密着性が低下する。これを防ぐために、伝熱管の材質や内面フィンの形状に合わせて、内面フィンの倒れが生じづらい拡管ロッドが様々に開発されている(例えば特許文献1、2)。   In the step of expanding the heat transfer tube by pushing the tube expansion plug (expansion step), the inner fins of the heat transfer tube may fall down. If the inner fins fall down, the heat transfer tubes cannot be expanded until the heat transfer tubes have a predetermined outer diameter, and the adhesion between the heat transfer tubes and the plate fins decreases. In order to prevent this, various tube expansion rods have been developed in which the inner fins do not easily fall down in accordance with the material of the heat transfer tube and the shape of the inner fins (for example, Patent Documents 1 and 2).

特開2011−208823号公報JP 2011-208823 A 特許第4913371号公報Japanese Patent No. 4913371

近年、エアコン性能の向上と消費電力の節約に伝熱管には更なる熱伝達性能の向上が要求されており、その中で、幅が細く内面フィン高さの高いハイスリムフィンを有する伝熱管が使用されている。しかしながら、ハイスリムフィン化するにつれて、拡管時に内面フィンが倒れやすくなるという問題があった。   In recent years, heat transfer tubes have been required to further improve heat transfer performance in order to improve air conditioner performance and save power consumption. Among them, heat transfer tubes with high slim fins with narrow width and high inner fin height are required. It is used. However, there is a problem that the inner fin tends to fall down when expanding the tube as the high slim fin is formed.

また、銅資源の枯渇などの背景から、伝熱管として軽量で安価なアルミニウム又はアルミニウム合金から形成する要求が高まっている。アルミニウム及びアルミニウム合金は、銅合金に比べて強度に劣るため、耐圧強度の面から伝熱管の底肉厚を銅合金を用いた場合に比べて厚くする必要がある。したがって、拡管時に拡管プラグ挿入方向に加わる荷重(拡管荷重)が増大し伝熱管の座屈が発生し易くなるという問題があった。   In addition, from the background of depletion of copper resources and the like, there is an increasing demand for forming heat transfer tubes from light and inexpensive aluminum or aluminum alloys. Since aluminum and aluminum alloy are inferior in strength to copper alloy, it is necessary to make the bottom wall thickness of the heat transfer tube thicker than that in the case of using copper alloy in terms of pressure strength. Therefore, there has been a problem that the load (expanded load) applied in the expanded plug insertion direction at the time of expanding the tube increases and the heat transfer tube is likely to buckle.

本発明は、以上のような従来の実情に鑑みなされたものであり、拡管時の伝熱管の座屈を抑制しつつ、及び内面フィンの倒れを抑制する拡管プラグの提供を目的とする。   The present invention has been made in view of the above-described conventional situation, and an object of the present invention is to provide a tube expansion plug that suppresses buckling of a heat transfer tube during tube expansion and suppresses collapse of an inner fin.

本発明者らの鋭意検討により、拡管時に生じる内面フィンの倒れ、並びに拡管時の拡管荷重は、伝熱管の内周面と当接する拡管プラグのヘッド部の曲率半径と相関があることがわかった。内面フィンの倒れの抑制にはヘッド部の曲率半径を大きくすることが有効であり、拡管荷重の低減には小さくすることが有効である。即ち、内面フィンの倒れ抑制と拡管荷重の低減は、互いに相反する曲率半径により効果を得るものである。   As a result of intensive studies by the present inventors, it has been found that the collapse of the inner fin that occurs during tube expansion and the tube expansion load during tube expansion correlate with the curvature radius of the head portion of the tube expansion plug that contacts the inner peripheral surface of the heat transfer tube. . Increasing the radius of curvature of the head portion is effective for suppressing the collapse of the inner fins, and decreasing the tube expansion load is effective. That is, the suppression of the falling of the inner fin and the reduction of the tube expansion load are effective due to the mutually opposite curvature radii.

本発明者らはさらに鋭意検討を進め、拡管荷重は、伝熱管に拡管プラグを挿入する時の拡管荷重(初期拡管荷重)が最も大きくなることを見出した。したがって、伝熱管の座屈は、拡管プラグを挿入する際に最もおこりやすい。本発明者らは、この初期拡管荷重を低減することで座屈を抑制できることに着目して、本発明を完成するに至った。
即ち、拡管プラグのヘッド部の先端側に曲率半径の比較的小さな予備拡管部を設け、初期拡管荷重を低減させた。さらに、予備拡管部より後端側には、曲率半径の比較的大きな主拡管部を設け、内面フィン倒れを低減させた。これによって、この拡管プラグは、拡管工程における内面フィン倒れの抑制と伝熱管の座屈の抑制を同時に実現できる。
The inventors of the present invention have further intensively studied and found that the tube expansion load is the largest when the tube expansion plug is inserted into the heat transfer tube (initial tube expansion load). Therefore, the heat transfer tube is most likely to buckle when the tube expansion plug is inserted. The inventors of the present invention have completed the present invention by paying attention to the fact that buckling can be suppressed by reducing the initial tube expansion load.
That is, a preliminary tube expansion portion having a relatively small radius of curvature is provided on the distal end side of the head portion of the tube expansion plug to reduce the initial tube expansion load. Further, a main pipe expanding section having a relatively large radius of curvature is provided on the rear end side from the preliminary pipe expanding section to reduce the inner fin collapse. Thereby, this pipe expansion plug can simultaneously realize the suppression of the internal fin collapse and the suppression of the heat transfer tube buckling in the pipe expansion process.

本発明の拡管プラグは、所定間隔に平行に並設する複数の放熱フィンに形成された挿通孔に、内周面に複数の内面フィンが形成された伝熱管を通し拡管することで前記放熱フィンに密着させるために、前記伝熱管に挿入する拡管プラグであって、軸部と、その先端側に形成されるヘッド部と、を有し、前記ヘッド部は、その横断面が先端部から最大径部まで徐々に直径を大きくする略円形状であり、先端部から最大径部の間に滑らかに接続される予備拡管部と主拡管部とを備え、前記予備拡管部は、前記伝熱管の最小管内径より小径の先端部から前記最小管内径より大径の予備拡管終了部までを5mm以上7.9mm以下の曲率半径で接続し、前記主拡管部は、前記予備拡管終了部から前記最大径部までを20.1mm以上30mm以下の曲率半径で接続し、前記予備拡管終了部の直径である予備拡管終了径が、以下の下記式で表されることを特徴とする。
={K×β×(α−α)/α}+β
ただし、Dは、予備拡管終了径であり、Kは0.45以上0.65以下の予備拡管係数であり、βは、拡管前の前記伝熱管の最小管内径であり、αは、拡管前の前記伝熱管の外径であり、αは、拡管後の前記伝熱管の外径である。
The tube expansion plug of the present invention is configured such that the heat radiation fin is expanded by passing through a heat transfer tube in which a plurality of inner surface fins are formed on an inner peripheral surface through insertion holes formed in a plurality of heat radiation fins arranged in parallel at a predetermined interval. An expansion plug to be inserted into the heat transfer tube, and has a shaft portion and a head portion formed on the tip side thereof, and the cross-section of the head portion is maximum from the tip portion. It has a substantially circular shape that gradually increases in diameter to the diameter portion, and includes a preliminary expanded portion and a main expanded portion that are smoothly connected between the distal end portion and the maximum diameter portion, and the preliminary expanded portion is formed of the heat transfer tube. A tip having a smaller diameter than the minimum pipe inner diameter is connected to a pre-expansion end portion having a diameter larger than the minimum pipe inner diameter with a radius of curvature of not less than 5 mm and not more than 7.9 mm. 20.1mm or more and 30mm or less Connected by a radius, the preliminary tube expansion terminates diameter is the diameter of the pre-expanded pipe termination unit, characterized by being represented by the following formula.
D 2 = {K × β × (α 2 −α 1 ) / α 1 } + β
However, D 2 is the pre-expanded tube ends diameter, K is a spare tube expansion coefficient of 0.45 to 0.65, beta is the minimum tube inner diameter of the heat transfer tube of the prior tube expansion, alpha 1 is an outer diameter of the heat transfer tube of the prior tube expansion, alpha 2 is the outer diameter of the heat transfer tube after the tube expansion.

また、本発明の拡管プラグは、前記伝熱管が、アルミニウム又はアルミニウム合金からなり、拡管前の前記伝熱管の底肉厚tに対する外径αの比(α/t)が、7以上16以下であり、拡管前の前記内面フィンのフィンピッチiに対するフィン幅jの比(j/i)が、0.1以上0.7以下であってもよい。 In the tube expansion plug of the present invention, the heat transfer tube is made of aluminum or an aluminum alloy, and the ratio (α 1 / t) of the outer diameter α 1 to the bottom wall thickness t of the heat transfer tube before tube expansion is 7 or more and 16 The ratio (j / i) of the fin width j to the fin pitch i of the inner surface fin before tube expansion may be 0.1 or more and 0.7 or less.

また、本発明の拡管プラグは、前記最大径部と当該最大径部より小径の後端部の間に後面拡管部を有し、前記後面拡管部は、前記最大径部から前記後端部までを10mm以下の曲率半径で接続していてもよい。   The tube expansion plug of the present invention has a rear surface tube expansion portion between the maximum diameter portion and a rear end portion having a smaller diameter than the maximum diameter portion, and the rear surface tube expansion portion extends from the maximum diameter portion to the rear end portion. May be connected with a radius of curvature of 10 mm or less.

本発明の拡管プラグは、ヘッド部の先端側に、曲率半径が比較的小さい予備拡管部が形成されている。これによって、拡管プラグを伝熱管に挿入する際の初期拡管荷重を低減し、伝熱管の座屈を抑制できる。また、予備拡管部の後方には、曲率半径が比較的大きい主拡管部が形成されている。これによって、主拡管部での拡管を行う際に、内面フィンが倒れることを抑制できる。
したがって、互いに相反する座屈の抑制と内面フィン倒れの軽減を同時に実現することができる。本発明の拡管プラグによれば、座屈が起こりにくく、内面フィンの倒れの少ない熱交換器の製造方法を提供できる。
In the tube expansion plug of the present invention, a preliminary tube expansion portion having a relatively small radius of curvature is formed on the tip side of the head portion. As a result, the initial tube expansion load when the tube expansion plug is inserted into the heat transfer tube can be reduced, and buckling of the heat transfer tube can be suppressed. Further, a main pipe expanding portion having a relatively large radius of curvature is formed behind the preliminary pipe expanding portion. Thereby, it is possible to prevent the inner fin from falling when the main expansion portion is expanded.
Therefore, it is possible to simultaneously achieve the suppression of buckling and the reduction of the inner fin collapse which are opposite to each other. According to the pipe expansion plug of the present invention, it is possible to provide a method for manufacturing a heat exchanger in which buckling is unlikely to occur and the inner fins are less likely to collapse.

本発明の実施形態に係る拡管プラグにより伝熱管を拡管して熱交換器を組み立てる手順を示す斜視図である。It is a perspective view which shows the procedure which expands a heat exchanger tube with the tube expansion plug which concerns on embodiment of this invention, and assembles a heat exchanger. 同拡管プラグにより伝熱管を拡管して伝熱管に加工する拡管動作を示す部分断面図であり、図2(a)は拡管プラグを伝熱管の開口部に挿入しようとする瞬間の状態を示し、図2(b)は拡管プラグを伝熱管の開口部から挿入し把持治具によるクランプを行う直前の状態を示す。FIG. 2A is a partial cross-sectional view showing a tube expansion operation of expanding the heat transfer tube into the heat transfer tube by the tube expansion plug, and FIG. 2A shows a state at the moment of trying to insert the tube expansion plug into the opening of the heat transfer tube; FIG. 2B shows a state immediately before the tube expansion plug is inserted from the opening of the heat transfer tube and clamped by the holding jig. 同拡管プラグにより拡管される伝熱素管の一例を示す横断面図であり、図3(a)は、断面全体を示し、図3(b)は内面フィンを拡大して示す。It is a cross-sectional view showing an example of a heat transfer element tube expanded by the tube expansion plug, FIG. 3 (a) shows the entire cross section, FIG. 3 (b) shows an enlarged inner fin. 螺旋溝が形成された伝熱管の一例を示す断面図を示す。Sectional drawing which shows an example of the heat exchanger tube in which the spiral groove was formed is shown. 本発明の一実施形態である拡管プラグを示す側面図であり、図5(a)は拡管プラグ全体を示し、図5(b)はヘッド部を拡大して示す。It is a side view which shows the pipe expansion plug which is one Embodiment of this invention, Fig.5 (a) shows the whole pipe expansion plug, FIG.5 (b) expands and shows a head part. 従来の拡管プラグのヘッド部の一例を示す側面図である。It is a side view which shows an example of the head part of the conventional pipe expansion plug. 従来の拡管プラグによる拡管工程において、ストロークと拡管荷重の関係を示すグラフである。It is a graph which shows the relationship between a stroke and a pipe expansion load in the pipe expansion process by the conventional pipe expansion plug. 従来の拡管プラグによる拡管工程において、ヘッド部の前面曲部の曲率半径と拡管荷重及びフィン高さ減少率の関係を示すグラフである。It is a graph which shows the relationship between the curvature radius of the front curved part of a head part, a pipe expansion load, and a fin height reduction rate in the pipe expansion process by the conventional pipe expansion plug.

以下、本発明の一実施形態について図面を参照しながら説明する。
なお、以下の説明で用いる図面は、特徴部分を強調する目的で、便宜上特徴となる部分を拡大して示している場合があり、各構成要素の寸法比率などが実際と同じであるとは限らない。また、同様の目的で、特徴とならない部分を省略して図示している場合がある。
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In the drawings used in the following description, for the purpose of emphasizing the feature portion, the feature portion may be shown in an enlarged manner for convenience, and the dimensional ratios of the respective constituent elements are not always the same as in practice. Absent. In addition, for the same purpose, portions that are not characteristic may be omitted from illustration.

<拡管工程>
図1に本発明の一実施形態である拡管プラグ1を用いた熱交換器の製造方法を示す。
この製造方法は、所定間隔に平行に並設する複数のフィン材15(放熱フィン)に形成された挿通孔15aに伝熱管11を通した状態で、伝熱管11に拡管プラグ1を挿入して拡管し伝熱管11の外周をフィン材15の挿通孔15aの内径部に密着させて熱交換器を製造する方法である。
<Tube expansion process>
FIG. 1 shows a method for manufacturing a heat exchanger using a tube expansion plug 1 according to an embodiment of the present invention.
In this manufacturing method, the expansion plug 1 is inserted into the heat transfer tube 11 in a state where the heat transfer tube 11 is inserted into the insertion holes 15a formed in the plurality of fin members 15 (radiation fins) arranged in parallel at a predetermined interval. In this method, the heat exchanger is manufactured by expanding the tube and bringing the outer periphery of the heat transfer tube 11 into close contact with the inner diameter portion of the insertion hole 15 a of the fin material 15.

以下にこの拡管工程の具体的な手順について説明する。
まず、アルミニウムあるいはアルミニウム合金製のフィン材15を複数重ねてフィン集合体16を構成する。各フィン材15において伝熱管11を挿通する予定位置には、挿通孔15aが形成されている。これらの挿通孔15aが一直線状に並ぶように各フィン材15を配置する。
また、伝熱管11をU字状に曲げてヘアピンパイプを構成しておく。これにより伝熱管11の開口部11aは、一側にそろえられ他側にU字部11bが形成される。このペアピンパイプ(伝熱管11)を必要本数フィン集合体16の挿通孔15aに挿通する。各伝熱管11の開口部11aはフィン集合体16の一側に揃えておく。
The specific procedure of this pipe expansion process is demonstrated below.
First, the fin assembly 16 is formed by stacking a plurality of aluminum or aluminum alloy fin materials 15. An insertion hole 15 a is formed at a position where the heat transfer tube 11 is inserted in each fin material 15. The fin members 15 are arranged so that the insertion holes 15a are aligned in a straight line.
Further, the heat transfer tube 11 is bent into a U shape to form a hairpin pipe. Thereby, the opening part 11a of the heat exchanger tube 11 is aligned on one side, and the U-shaped part 11b is formed on the other side. The pair pin pipe (heat transfer tube 11) is inserted into the insertion hole 15 a of the required number of fin assemblies 16. The opening 11a of each heat transfer tube 11 is arranged on one side of the fin assembly 16.

この状態において各伝熱管11の開口部11aから拡管プラグ1を強制的に押し込む。ヘッド部3が伝熱管11を拡管する拡管動作を部分断面図として図2(a)、(b)に示す。
図2(a)に示すように、開口部11aから拡管プラグ1のヘッド部3を強制的に押し込む。これによって、開口部11aから順にヘッド部の外周面に沿って伝熱管11の拡管が行われる。
図2(b)に示すように、ヘッド部3が開口部11aより内側に完全に入ったところで、開口部11a近傍の伝熱管11外周を把持治具でクランプする。ここまで(把持治具によるクランプを行うまで)の拡管工程は、伝熱管11の長手方向に対し圧縮力が加わる押込み式(縮み式)の拡管工程と呼ばれる。
In this state, the tube expansion plug 1 is forcibly pushed through the opening 11a of each heat transfer tube 11. 2 (a) and 2 (b) are partial cross-sectional views showing the tube expansion operation in which the head unit 3 expands the heat transfer tube 11. FIG.
As shown in FIG. 2A, the head portion 3 of the tube expansion plug 1 is forcibly pushed through the opening portion 11a. Thereby, the heat transfer tube 11 is expanded along the outer peripheral surface of the head portion in order from the opening 11a.
As shown in FIG. 2B, when the head portion 3 is completely inside the opening portion 11a, the outer periphery of the heat transfer tube 11 in the vicinity of the opening portion 11a is clamped with a gripping jig. The tube expansion process up to this point (until clamping by the holding jig) is called a push-type (contraction-type) tube expansion process in which a compressive force is applied to the longitudinal direction of the heat transfer tube 11.

把持治具によるクランプ工程以降も、ヘッド部3が伝熱管11のU字部11b近傍に到達するまでヘッド部3を強制的に押込む。このとき、把持治具により伝熱管11の開口部11aが固定(クランプ)されているため、伝熱管11には長手方向に対し引張力が加わる。このように、クランプ工程以降の拡管工程は伝熱管11に引張力が加わり吊下げ式(縮みレス式)の拡管工程と呼ばれる。   Even after the clamping process by the gripping jig, the head unit 3 is forcibly pushed in until the head unit 3 reaches the vicinity of the U-shaped part 11b of the heat transfer tube 11. At this time, since the opening 11a of the heat transfer tube 11 is fixed (clamped) by the holding jig, a tensile force is applied to the heat transfer tube 11 in the longitudinal direction. In this way, the tube expansion process after the clamping process is called a suspension type (contraction-less type) tube expansion process in which a tensile force is applied to the heat transfer tube 11.

押込み式、吊下げ式の拡管工程において、拡管プラグ1のヘッド部3が伝熱管11を押し広げて塑性変形させて伝熱管11を拡管できる。拡管された伝熱管11はフィン材15の挿通孔15aを押し広げるようにフィン材15に結合するので、伝熱管11をフィン材15に機械的に接合できる。   In the push-in and suspension-type tube expansion process, the head portion 3 of the tube expansion plug 1 can expand the heat transfer tube 11 by pushing the heat transfer tube 11 and plastically deforming it. Since the expanded heat transfer tube 11 is joined to the fin material 15 so as to push the insertion hole 15 a of the fin material 15, the heat transfer tube 11 can be mechanically joined to the fin material 15.

次に、把持治具によるクランプを解除しこの拡管プラグ1を引き抜く。この工程は引抜工程と呼ばれる。吊下げ式の拡管工程が終了した時点で、伝熱管11には拡管が行われている。したがって、引抜工程は伝熱管11の塑性変形を行わない。ただし、把持治具によるクランプを経ることによって、伝熱管11の開口部11aの近傍は縮径されている。したがって引抜工程では、開口部11aの拡管を再度行うことになる。
以上の工程を経て、拡管工程が完了する。図2(a)、(b)に示すように拡管プラグを挿入することで、伝熱管11の外径は、拡管前外径αから拡管後外径αに拡管される。
Next, the clamp by the holding jig is released, and the tube expansion plug 1 is pulled out. This process is called a drawing process. When the suspension-type tube expansion process is completed, the heat transfer tube 11 is expanded. Therefore, the drawing process does not plastically deform the heat transfer tube 11. However, the vicinity of the opening 11a of the heat transfer tube 11 is reduced in diameter by being clamped by a holding jig. Therefore, in the drawing process, the opening 11a is expanded again.
Through the above steps, the tube expansion step is completed. FIG. 2 (a), the by inserting a tube expanding plug (b), the outer diameter of the heat transfer tube 11 is expanded tube from the expanded tube before the outer diameter alpha 1 the tube expanding Kosoto径alpha 2.

<伝熱管>
図3(a)に、本実施形態の拡管プラグ1によって拡管される伝熱管11の拡管前の断面図を示す。また、図3(b)に、図3(a)に示す伝熱管11の内面フィン12の一部の拡大図を示す。
伝熱管11の内周面には、中心に向いて突出する内面フィン12が複数形成されている。内面フィン12は、伝熱管11の長さ方向全長に渡り延在するように、伝熱管11の内周面周方向に所定の間隔で複数隣接形成されている。内面フィン12は周方向に沿って例えば、30〜72個形成されている。
伝熱管11は、例えば銅合金、アルミニウム又はアルミニウム合金を押出加工することでこのような断面形状を得ることができる。
<Heat transfer tube>
FIG. 3A shows a cross-sectional view of the heat transfer tube 11 expanded by the tube expansion plug 1 of the present embodiment before expansion. FIG. 3B is an enlarged view of a part of the inner fin 12 of the heat transfer tube 11 shown in FIG.
A plurality of internal fins 12 projecting toward the center are formed on the inner peripheral surface of the heat transfer tube 11. A plurality of inner fins 12 are formed adjacent to each other at a predetermined interval in the circumferential direction of the inner peripheral surface of the heat transfer tube 11 so as to extend over the entire length of the heat transfer tube 11. For example, 30 to 72 inner fins 12 are formed along the circumferential direction.
The heat transfer tube 11 can obtain such a cross-sectional shape by extruding, for example, a copper alloy, aluminum, or an aluminum alloy.

内面フィン12は、伝熱管11の横断面において、伝熱管11の中心に向く頂部12aとこの頂部12aを挟むように延在する傾斜部12b、12bとを有する横断面視等脚台形状に形成されている。これらの内面フィン12は、伝熱管11の内周面の周方向に所定の間隔で複数形成されているので、隣接する内面フィン12、12の間にフィン溝14が形成されている。
内面フィン12の高さhは例えば0.05mm〜0.35mm程度とされる。また、内面フィン12のフィン幅jは、例えば0.05mm〜0.4mmとされる。なお、フィン幅jとは、内面フィン12の頂部の幅を意味し、図3(b)に示すように頂部12aが断面半円形状を有する場合においては、頂部の半円形状の直径となる。内面フィン12のフィンピッチi(即ちフィン溝14の幅)は、伝熱管11の内径と、形成される内面フィン12の個数によって決まり、例えば0.05mm〜0.7mmとされる。
The inner fin 12 is formed in an isosceles trapezoidal shape in a cross-sectional view having a top portion 12a facing the center of the heat transfer tube 11 and inclined portions 12b and 12b extending so as to sandwich the top portion 12a in the cross section of the heat transfer tube 11. Has been. Since a plurality of these inner surface fins 12 are formed at predetermined intervals in the circumferential direction of the inner peripheral surface of the heat transfer tube 11, a fin groove 14 is formed between the adjacent inner surface fins 12, 12.
The height h of the inner fin 12 is, for example, about 0.05 mm to 0.35 mm. Moreover, the fin width j of the inner surface fin 12 shall be 0.05 mm-0.4 mm, for example. The fin width j means the width of the top portion of the inner fin 12, and when the top portion 12a has a semicircular cross section as shown in FIG. . The fin pitch i of the inner fins 12 (that is, the width of the fin grooves 14) is determined by the inner diameter of the heat transfer tube 11 and the number of inner fins 12 formed, and is, for example, 0.05 mm to 0.7 mm.

伝熱管11の内面に内面フィン12を設けることで、伝熱管11の内面の表面積を大きくして熱伝達効率を高めることができる。さらに熱伝達効率を大きくするためには、フィン幅jが細く内面フィンが高い(即ち高さhが大きい)ハイスリムフィンが有効である。しかしながら、ハイスリムフィン化するにつれて、拡管プラグ1を挿入する際に内面フィン12が倒れやすくなる。内面フィン12の倒れが発生すると、伝熱管の伝熱特性が低下するのみならず、所定の拡管率を得ることができなくなり、伝熱管11とフィン材15の挿通孔15a(図1参照)が十分に密着せず、熱交換器としての性能が大きく低下する。後段において詳しく説明するヘッド部3を備えた拡管プラグ1を用いて拡管を行うことによって、内面フィンの倒れを抑制できる。   By providing the inner surface fins 12 on the inner surface of the heat transfer tube 11, the surface area of the inner surface of the heat transfer tube 11 can be increased to increase the heat transfer efficiency. In order to further increase the heat transfer efficiency, a high slim fin having a narrow fin width j and a high inner fin (that is, a large height h) is effective. However, as the high slim fin is formed, the inner fin 12 tends to fall when the tube expansion plug 1 is inserted. When the inner fin 12 falls, not only the heat transfer characteristics of the heat transfer tube are deteriorated, but also a predetermined tube expansion rate cannot be obtained, and the heat transfer tube 11 and the insertion hole 15a (see FIG. 1) of the fin material 15 are provided. It does not adhere sufficiently, and the performance as a heat exchanger is greatly reduced. By performing the pipe expansion using the pipe expansion plug 1 provided with the head portion 3 which will be described in detail later, it is possible to suppress the collapse of the inner fin.

伝熱管11の底肉厚t(フィン溝14に対応する部分の管の肉厚)は、0.3mm〜0.8mm程度とされる。伝熱管11の外径α(拡管前外径α)は、例えば5〜10mm程度とされる。この伝熱管11は、拡管プラグ1が挿入され3%〜8%の拡管率で拡管される。即ち、拡管後の外径α(拡管後外径α)は、5.15mm〜10.8mmとされる。 The bottom wall thickness t of the heat transfer tube 11 (the wall thickness of the tube corresponding to the fin groove 14) is about 0.3 mm to 0.8 mm. The outer diameter α 1 of the heat transfer tube 11 (outer diameter before expansion α 1 ) is, for example, about 5 to 10 mm. The heat transfer tube 11 is expanded at a tube expansion rate of 3% to 8% with the tube expansion plug 1 inserted. That is, the outer diameter α 2 after pipe expansion (outer diameter after pipe expansion α 2 ) is set to 5.15 mm to 10.8 mm.

伝熱管11は、銅合金、アルミニウム又はアルミニウム合金からなるものを用いることができる。
伝熱管11にアルミニウム合金を用いる場合は、そのアルミニウム合金に特に制限はなく、JISで規定される1050、1100、1200等の純アルミニウム系、あるいは、これらにMnを添加した3003に代表される3000系のアルミニウム合金等を適用できる。勿論、これら以外にJISに規定されている5000系〜7000系のアルミニウム合金のいずれかを用いて伝熱管11を構成しても良い。
The heat transfer tube 11 may be made of copper alloy, aluminum, or aluminum alloy.
When an aluminum alloy is used for the heat transfer tube 11, the aluminum alloy is not particularly limited, and is typically pure aluminum such as 1050, 1100, 1200, etc. defined by JIS, or 3000 represented by 3003 with Mn added thereto. A series aluminum alloy or the like can be applied. Of course, you may comprise the heat exchanger tube 11 using either the 5000 type | system | group -7000 type | system | group aluminum alloy prescribed | regulated to JIS other than these.

アルミニウム又はアルミニウム合金は、銅合金に比べて強度に劣る。したがって、耐圧強度の面から伝熱管11の底肉厚tを銅合金で形成した伝熱管の底肉厚と比較して厚くする必要がある。底肉厚tが厚いアルミニウム及びアルミニウム合金からなる伝熱管11を拡管しようとすると、拡管荷重が大きくなる。これにより、アルミニウム又はアルミニウム合金からなる伝熱管11は、拡管工程において座屈が発生しやすくなる。   Aluminum or an aluminum alloy is inferior in strength to a copper alloy. Therefore, it is necessary to make the bottom wall thickness t of the heat transfer tube 11 thicker than the bottom wall thickness of the heat transfer tube formed of a copper alloy in terms of pressure resistance. When the heat transfer tube 11 made of aluminum and aluminum alloy having a thick bottom wall thickness t is to be expanded, the tube expansion load increases. Thereby, the heat transfer tube 11 made of aluminum or an aluminum alloy is likely to be buckled in the tube expansion process.

伝熱管11としてアルミニウム又はアルミニウム合金を用いる場合において、拡管前の伝熱管11の底肉厚tに対する伝熱管11の外径αの比(α/t)が、7以上16以下であることが好ましい。
α/tが、7に満たない場合は、アルミニウム又はアルミニウム合金からなる伝熱管11の拡管時の拡管荷重が大きくなる。これにより、伝熱管11に座屈が生じやすくなる。また、拡管荷重が大きくなるために、拡管時に内面フィン12に加わる力が大きくなり、内面フィン12の倒れが生じやすくなる。α/tが、11を超える場合は、アルミニウム又はアルミニウム合金からなる伝熱管11の耐圧強度が下がり好ましくない。
When aluminum or an aluminum alloy is used as the heat transfer tube 11, the ratio (α 1 / t) of the outer diameter α 1 of the heat transfer tube 11 to the bottom wall thickness t of the heat transfer tube 11 before the expansion is 7 or more and 16 or less. Is preferred.
When α 1 / t is less than 7, the tube expansion load when the heat transfer tube 11 made of aluminum or an aluminum alloy is expanded becomes large. Thereby, the heat transfer tube 11 is likely to buckle. In addition, since the tube expansion load is increased, the force applied to the inner surface fins 12 during tube expansion is increased, and the inner surface fins 12 are liable to fall. When α 1 / t exceeds 11, the pressure resistance of the heat transfer tube 11 made of aluminum or an aluminum alloy is lowered, which is not preferable.

また、伝熱管11の内面フィン12について、フィンピッチiに対しフィン幅jを大きくすると、拡管時の拡管荷重が大きくなり伝熱管11に座屈が生じやすくなる。また、フィンピッチiに対しフィン幅jを小さくすると、内面フィン12が細長く立設された形状となるため内面フィン12の倒れが生じやすくなる。したがって、アルミニウム又はアルミニウム合金からなる伝熱管11を用いた場合においては、伝熱管11の拡管前の内面フィン12のフィンピッチiに対するフィン幅jの比(j/i)が、0.1以上0.7以下であることが好ましい。   Further, regarding the inner fin 12 of the heat transfer tube 11, if the fin width j is increased with respect to the fin pitch i, the tube expansion load at the time of tube expansion increases and the heat transfer tube 11 is likely to buckle. Further, when the fin width j is reduced with respect to the fin pitch i, the inner fin 12 is erected in an elongated shape, so that the inner fin 12 is likely to fall down. Therefore, when the heat transfer tube 11 made of aluminum or an aluminum alloy is used, the ratio (j / i) of the fin width j to the fin pitch i of the inner surface fin 12 before the expansion of the heat transfer tube 11 is 0.1 or more and 0. .7 or less is preferable.

<伝熱管の別の例>
本実施形態の拡管プラグ1は、上述した伝熱管11の他に、内面フィン22が螺旋状に形成された螺旋溝付伝熱管20(伝熱管20)を用いてもよい。
図4に本発明に適用できる螺旋溝付伝熱管20の縦断面構造を示す。この伝熱管20は、銅合金、アルミニウム又はアルミニウム合金からなるものを用いることができる。また、この伝熱管20は、上述した伝熱管11と同様に、内周に突条型の内面フィン22が形成され、隣接する内面フィン間にフィン溝23が形成されている。また、伝熱管11と、同等範囲の拡管前後の外径、並びに拡管前の底肉厚、フィン幅、フィンピッチを満たす。
<Another example of heat transfer tube>
In addition to the heat transfer tube 11 described above, the tube expansion plug 1 of the present embodiment may use a heat transfer tube 20 with a spiral groove (inner heat transfer tube 20) in which inner fins 22 are formed in a spiral shape.
FIG. 4 shows a longitudinal sectional structure of a heat transfer tube 20 with a spiral groove applicable to the present invention. The heat transfer tube 20 may be made of copper alloy, aluminum, or aluminum alloy. Further, in the heat transfer tube 20, similarly to the heat transfer tube 11 described above, a protruding inner fin 22 is formed on the inner periphery, and a fin groove 23 is formed between adjacent inner fins. Moreover, the outer diameter before and after the expansion of the heat transfer tube 11 and the equivalent range, the bottom thickness before the expansion, the fin width, and the fin pitch are satisfied.

この例の伝熱管20において、上述した伝熱管11と異なる点は、内面フィン22が伝熱管20の内周面に沿ってその長さ方向に螺旋を描くように形成されている点である。
伝熱管20の内面に形成されている複数の内面フィン22は全ての内面フィン22が同じピッチで螺旋状に形成されていて、内面フィン22の間に形成されているフィン溝23についても伝熱管20の内部において所定のピッチで螺旋を描くように、即ち螺旋溝状に形成されている。
The heat transfer tube 20 of this example is different from the heat transfer tube 11 described above in that the inner fin 22 is formed so as to draw a spiral along the inner peripheral surface of the heat transfer tube 20 in its length direction.
The plurality of inner surface fins 22 formed on the inner surface of the heat transfer tube 20 are all formed in a spiral shape at the same pitch, and the fin groove 23 formed between the inner surface fins 22 is also the heat transfer tube. 20 is formed in a spiral groove shape so as to draw a spiral at a predetermined pitch.

内面フィン22を伝熱管20の長さ方向に対し螺旋状に形成することで、伝熱管20に冷媒が流れる際、冷媒との熱交換効率を良好にすることができる。
本実施形態の拡管プラグ1は、長手方向に対し螺旋状に形成された内面フィン22を備えた伝熱管20であっても、座屈及び内面フィン22の倒れを抑制しつつ拡管できる。
By forming the inner fin 22 in a spiral shape with respect to the length direction of the heat transfer tube 20, when the refrigerant flows through the heat transfer tube 20, the heat exchange efficiency with the refrigerant can be improved.
Even if it is the heat exchanger tube 20 provided with the inner surface fin 22 formed helically with respect to the longitudinal direction, the tube expansion plug 1 of the present embodiment can be expanded while suppressing buckling and the collapse of the inner surface fin 22.

<従来工法の拡管荷重と内面フィンの倒れについて>
従来の拡管プラグを用い上段に説明した拡管工程を行った場合の、拡管荷重と内面フィンの倒れについて説明する。
<Tube expansion load of conventional method and internal fin collapse>
The tube expansion load and the collapse of the inner fin when the tube expansion process described above is performed using a conventional tube expansion plug will be described.

図6に、一例として従来用いられている拡管プラグ101のヘッド部103を示す。なお、この拡管プラグ101の横断面形状は円形である。
拡管プラグ101は支持棒102の先端にヘッド部103が固定されている。ヘッド部103は、樽型に膨出して形成されており、側面から見た中央部には最大径部103cが形成されている。先端部103aから最大径部103cまでは、徐々に径が大きくなり、最大径部103cから後端部103dまでは、徐々に径が小さくなっている。
先端部103aから最大径部103cまでは、1つの曲面である前面曲部106により接続されている。この前面曲部106の曲率半径rで形成されている。
最大径部103cから後端部103dまでは、1つの曲面である後面曲部107により接続されている。
FIG. 6 shows a head portion 103 of a tube expansion plug 101 conventionally used as an example. The tube expansion plug 101 has a circular cross-sectional shape.
The tube expansion plug 101 has a head portion 103 fixed to the tip of a support rod 102. The head portion 103 is formed to bulge into a barrel shape, and a maximum diameter portion 103c is formed at a central portion viewed from the side. The diameter gradually increases from the front end portion 103a to the maximum diameter portion 103c, and the diameter gradually decreases from the maximum diameter portion 103c to the rear end portion 103d.
The front end portion 103a to the maximum diameter portion 103c are connected by a front curved portion 106 that is one curved surface. The front curved portion 106 is formed with a radius of curvature r.
The maximum diameter portion 103c to the rear end portion 103d are connected by a rear curved portion 107 that is one curved surface.

図7に、従来の拡管プラグ101を用いた拡管工程におけるストローク(押込み量)と拡管荷重(拡管プラグに加わる挿入方向の荷重)の相関関係の一例を示す。なお、図7のグラフでは、引き抜き工程を省略している。
図7に示すように、拡管工程の拡管荷重は、拡管プラグ挿入直後にピークを迎える。これは、拡管プラグのヘッド部を伝熱管の開口部に挿入する際に最も大きな拡管荷重(初期拡管荷重)が生じることを意味する。初期拡管荷重は、一例として図2(a)に示す状態で発生する。初期拡管荷重は、押込み式の拡管工程(即ち把持治具によるクランプを行う前の工程)中に生じる。押込み式の拡管工程においては伝熱管に圧縮力が加わるため、この初期拡管荷重が発生する際に伝熱管の座屈が最も起こりやすくなる。したがって、伝熱管の座屈の発生を防ぐためには、初期拡管荷重を低減することが重要となる。
FIG. 7 shows an example of the correlation between the stroke (pushing amount) and the tube expansion load (load in the insertion direction applied to the tube expansion plug) in the tube expansion process using the conventional tube expansion plug 101. In the graph of FIG. 7, the drawing process is omitted.
As shown in FIG. 7, the tube expansion load in the tube expansion process reaches its peak immediately after the tube expansion plug is inserted. This means that the largest tube expansion load (initial tube expansion load) is generated when the head portion of the tube expansion plug is inserted into the opening of the heat transfer tube. The initial tube expansion load is generated in the state shown in FIG. The initial pipe expansion load is generated during the push-type pipe expansion process (that is, the process before clamping with the gripping jig). In the push-in type tube expansion process, a compressive force is applied to the heat transfer tube. Therefore, when the initial tube expansion load is generated, the heat transfer tube is most likely to buckle. Therefore, in order to prevent the occurrence of buckling of the heat transfer tube, it is important to reduce the initial tube expansion load.

初期拡管荷重は、前面曲部106の曲率半径rと相関関係を有する。従来の拡管プラグ101において、前面曲部106の曲率半径rを小さくすると、拡管荷重を低減できる。これに伴い初期拡管荷重も低減され拡管時の伝熱管11の座屈を抑制できる。これは、前面曲部106の曲率半径rを小さくすると、伝熱管の内周面とヘッド部103との挿入方向の接触部が短くなるため、拡管荷重が低減されると考えられる。   The initial tube expansion load has a correlation with the curvature radius r of the front curved portion 106. In the conventional pipe expansion plug 101, when the curvature radius r of the front curved portion 106 is reduced, the pipe expansion load can be reduced. Along with this, the initial tube expansion load is also reduced, and buckling of the heat transfer tube 11 during tube expansion can be suppressed. It is considered that when the radius of curvature r of the front curved portion 106 is reduced, the contact portion in the insertion direction between the inner peripheral surface of the heat transfer tube and the head portion 103 is shortened, so that the pipe expansion load is reduced.

また、内面フィンの倒れも前面曲部106の曲率半径rと相関関係を有する。拡管プラグ101において、前面曲部106の曲率半径rを小さくすると、内面フィン12の倒れが増加する。これは、伝熱管11の内周面と拡管プラグ101のヘッド部103との接触面積が小さくなることで、内面フィン12に加わる面圧が増加するためであると考えられる。   In addition, the fall of the inner fin has a correlation with the curvature radius r of the front curved portion 106. In the pipe expansion plug 101, when the curvature radius r of the front curved portion 106 is reduced, the fall of the inner fin 12 increases. This is considered to be because the contact pressure between the inner peripheral surface of the heat transfer tube 11 and the head portion 103 of the tube expansion plug 101 decreases, so that the surface pressure applied to the inner surface fins 12 increases.

図8に、初期拡管荷重及び内面フィンのフィン高さ減少率と前面曲部106の曲率半径rの関係のグラフを示す。なおフィン高さ減少率とは、拡管前後の内面フィン12の高さの減少率を示すものである。内面フィン12に倒れが生じるとフィン高さが減少し、このフィン高さ減少率が大きくなる。   FIG. 8 is a graph showing the relationship between the initial tube expansion load, the fin height reduction rate of the inner fins, and the curvature radius r of the front curved portion 106. The fin height reduction rate indicates the reduction rate of the height of the inner fin 12 before and after the pipe expansion. When the inner fin 12 falls, the fin height decreases, and the fin height reduction rate increases.

図8に示すように、前面曲部106の曲率半径rを大きくするに従い、拡管荷重は小さくなる。即ち、座屈が抑制される。逆にフィン高さ減少率は大きくなり、内面フィンの倒れが顕著となる。   As shown in FIG. 8, the tube expansion load decreases as the radius of curvature r of the front curved portion 106 increases. That is, buckling is suppressed. On the contrary, the fin height reduction rate becomes large, and the fall of the inner fin becomes remarkable.

図8に示すように、内面フィン12の倒れ抑制には前面曲部106の曲率半径rを大きくすることが有効である。また、拡管荷重の低減には前面曲部106の曲率半径rを小さくすることが有効である。内面フィン12の倒れと拡管荷重の低減は、ともに前面曲部106の曲率半径rと相関関係があり、互いに相反する条件が求められる。本発明の拡管プラグ1は、この相反する条件を満たし、内面フィン12の倒れ抑制と拡管荷重の低減を同時に実現するものである。   As shown in FIG. 8, it is effective to increase the radius of curvature r of the front curved portion 106 in order to prevent the inner fin 12 from collapsing. In order to reduce the tube expansion load, it is effective to reduce the radius of curvature r of the front curved portion 106. Both the fall of the inner fin 12 and the reduction of the tube expansion load have a correlation with the curvature radius r of the front curved portion 106, and mutually contradicting conditions are required. The pipe expansion plug 1 of the present invention satisfies the contradicting conditions, and realizes the suppression of the collapse of the inner fin 12 and the reduction of the pipe expansion load at the same time.

<拡管プラグ>
図5(a)は本発明に係る一実施形態の拡管プラグ1を示すものである。また、図5(b)は、この拡管プラグ1のヘッド部3を拡大したものである。
図5(a)に示すように、拡管プラグ1は、軸部2とその先端側に一体形成されたヘッド部3とからなる。軸部2の後端側にはねじ軸2aが形成されている。拡管プラグ1は、ねじ軸2aの部分に対し、嵌合自在なねじ穴を有する図示略の延長ロッドをねじ接合して拡管プラグ1の長さを調整できる。これにより、拡管プラグ1の長さを調整し、伝熱管11の全長に渡り、拡管できるように調整できる。
<Tube expansion plug>
FIG. 5A shows a tube expansion plug 1 according to an embodiment of the present invention. FIG. 5B is an enlarged view of the head portion 3 of the tube expansion plug 1.
As shown in FIG. 5A, the tube expansion plug 1 includes a shaft portion 2 and a head portion 3 that is integrally formed on the distal end side thereof. A screw shaft 2 a is formed on the rear end side of the shaft portion 2. The pipe expansion plug 1 can adjust the length of the pipe expansion plug 1 by screwing an unillustrated extension rod having a screw hole that can be fitted to the screw shaft 2a. Thereby, it is possible to adjust the length of the tube expansion plug 1 so that the tube can be expanded over the entire length of the heat transfer tube 11.

図5(b)に拡大図として示すように、ヘッド部3は、樽型をなして軸部2より径が大きくなるように膨出形成されている。ヘッド部3は、平坦面をなす先端部3aと、軸部2と接続される後端部3dとの間に最大径部3cが形成されている。また、ヘッド部3の横断面は、略円形に形成されている。横断面の直径は、先端部3aから最大径部3cにかけて徐々に大きくなっていき、最大径部3cから後端部3dにかけて徐々に小さくなっていく。先端部3aは直径Dに形成され、最大径部3cは直径Dに形成されている。
なお、横断面が「略円形」とは、円形である伝熱管11の内周に沿った形状であることを意味している。例えば、横断面円形のヘッド部3の表面に溝を形成して、横断面に凹凸が形成されていてもよい。
As shown in an enlarged view in FIG. 5B, the head portion 3 is formed in a barrel shape so as to bulge so as to have a diameter larger than that of the shaft portion 2. The head portion 3 is formed with a maximum diameter portion 3c between a tip portion 3a forming a flat surface and a rear end portion 3d connected to the shaft portion 2. Moreover, the cross section of the head part 3 is formed in a substantially circular shape. The diameter of the cross section gradually increases from the front end portion 3a to the maximum diameter portion 3c, and gradually decreases from the maximum diameter portion 3c to the rear end portion 3d. Distal end portion 3a is formed with a diameter D 1, the maximum diameter portion 3c is formed with a diameter D 3.
The “substantially circular” cross section means a shape along the inner periphery of the heat transfer tube 11 having a circular shape. For example, the groove | channel may be formed in the surface of the head part 3 with a circular cross section, and the unevenness | corrugation may be formed in the cross section.

ヘッド部3は、先端部3aから最大径部3cまでを前面拡管部6とされる。また、ヘッド部3は、最大径部3cから後端部3dまでを後面拡管部7とされる。即ち、ヘッド部3は、最大径部3cを境に先端側が前面拡管部6、後端側が後面拡管部7とされる。
先端部3aの直径Dは、拡管対象である伝熱管11の最小内径βより小さい径に形成されており伝熱管11の内径にスムーズに挿入できる。
The head portion 3 has a front surface expanded portion 6 from the tip portion 3a to the maximum diameter portion 3c. Further, the head portion 3 has a rear-surface expanded portion 7 from the maximum diameter portion 3c to the rear end portion 3d. That is, the head portion 3 has a front-side expanded portion 6 on the front end side and a rear-surface expanded portion 7 on the rear end side with the maximum diameter portion 3c as a boundary.
The diameter D 1 of the distal end portion 3a can be smoothly inserted into the inner diameter of the heat transfer tube 11 is formed to the minimum inner diameter β is smaller than the diameter of the heat transfer tube 11 is expanded tube target.

前面拡管部6は、拡管プラグ1を伝熱管に挿入する際に、伝熱管11を径方向外側に押し広げて拡管する役割を果たす。前面拡管部6は、それぞれ異なる曲率半径を有する予備拡管部6Aと主拡管部6Bに、予備拡管終了部3bを境として分けられる。
予備拡管部6Aは、曲率半径Rを有する一様な曲面である。また、主拡管部6Bは、曲率半径Rを有する一様な曲面である。
予備拡管部6Aの曲面と主拡管部6Bの曲面は、予備拡管終了部3bにおいて、滑らかに接続されている。即ち、予備拡管部6Aと主拡管部6Bは、縦断面をとった時に互いの接線の傾きが一致した点でエッヂを生じることなく接続されている。
The front surface expanded portion 6 plays a role of expanding and expanding the heat transfer tube 11 radially outward when the tube expansion plug 1 is inserted into the heat transfer tube. The front pipe expansion part 6 is divided into a preliminary pipe expansion part 6A and a main pipe expansion part 6B having different radii of curvature, with the preliminary pipe expansion end part 3b as a boundary.
Preliminary expanded portion 6A is a uniform curved surface having a radius of curvature R 1. The main expanded portion 6B is a uniform curved surface having a radius of curvature R 2.
The curved surface of the preliminary pipe expansion portion 6A and the curved surface of the main pipe expansion portion 6B are smoothly connected at the preliminary pipe expansion end portion 3b. In other words, the pre-expanded pipe 6A and the main pipe 6B are connected without causing an edge at the point where the inclinations of the tangent lines coincide with each other when the longitudinal section is taken.

予備拡管部6Aの曲率半径Rは、5mm以上7.9mm以下であることが好ましい。予備拡管部6Aは、伝熱管11の開口部11aに当接し、初期拡管荷重を受けながら伝熱管を最初に拡管する部分である(図2(a)参照)。したがって、この予備拡管部6Aの曲率半径Rを小さくすることで、伝熱管11の開口部11aに挿入した直後の拡管荷重(初期拡管荷重)を低減できる。予備拡管部6Aの曲率半径Rを7.9mm以下とすることで、初期拡管荷重を低減し、伝熱管11の座屈を抑制できる。また、予備拡管部6Aの曲率半径Rを5mm以上とすることで、内面フィン12の倒れを抑制できる。 The radius of curvature R 1 of the pre-expanded portion 6A is preferably 5mm or more 7.9mm or less. The pre-expanded tube portion 6A is a portion that abuts the opening 11a of the heat transfer tube 11 and first expands the heat transfer tube while receiving an initial tube expansion load (see FIG. 2A). Therefore, by reducing the radius of curvature R 1 of the pre-expanded pipe portion 6A, thereby reducing the pipe expansion load immediately after insertion into the opening 11a of the heat transfer tube 11 (initial tube expansion load). The radius of curvature R 1 of the pre-expanded portion 6A is set to be lower than or equal 7.9 mm, to reduce the initial tube expansion force can be suppressed buckling of the heat transfer tube 11. Further, the curvature radius R 1 of the pre-expanded pipe portion 6A With more than 5 mm, can be suppressed falling of the inner surface the fins 12.

主拡管部6Bの曲率半径Rは、20.1mm以上30mm以下であることが好ましい。主拡管部6Bは、伝熱管11の拡管工程において、予備拡管部6Aに沿って予備拡管された伝熱管11をさらに径方向外側に押し広げる役割を果たす(図2(b)参照)。したがって、主拡管部6Bは、予備拡管部6Aに対して内面フィン12に大きな負荷を加える。即ち、主拡管部6Bは、内面フィン12の倒れに対し支配的に作用する。主拡管部6Bの曲率半径Rを大きくすることで、内面フィン12の倒れを抑制できる。
主拡管部6Bの曲率半径Rが、20.1mm未満の場合は、内面フィン12の倒れが顕著となり好ましくない。また、30mmを超える場合は、拡管荷重が大きくなり、それに伴い、初期拡管荷重も大きくなる。したがって、伝熱管11の座屈発生の懸念が高まる。
The radius of curvature R 2 of the main expanded portion 6B is preferably 30mm or less than 20.1 mm. In the tube expansion process of the heat transfer tube 11, the main tube expansion portion 6B plays a role of further expanding the heat transfer tube 11 preliminarily expanded along the preliminary tube expansion portion 6A outward in the radial direction (see FIG. 2B). Accordingly, the main pipe expansion portion 6B applies a large load to the inner surface fin 12 with respect to the preliminary pipe expansion portion 6A. That is, the main pipe expanding portion 6B acts predominantly against the falling of the inner fin 12. By increasing the curvature radius R 2 of the main expanded portion 6B, it can be suppressed falling of the inner surface the fins 12.
The radius of curvature R 2 of the main expanded portion 6B is, in the case of less than 20.1 mm, the inclination of the inner surface the fins 12 is undesirably remarkable. Moreover, when it exceeds 30 mm, a pipe expansion load becomes large, and an initial stage pipe expansion load also becomes large in connection with it. Therefore, the concern about the occurrence of buckling of the heat transfer tube 11 is increased.

予備拡管部6Aと主拡管部6Bの境界となる予備拡管終了部3bの径D(予備拡管終了径D)は、伝熱管11の最小内径βより大きく形成されている。したがって、伝熱管11の最小内径部(即ち、内面フィン12の頂部)が予備拡管部6Aに当接することなく、主拡管部6Bに当接することはない。
また、予備拡管終了径Dは、予備拡管係数Kを0.45以上0.65以下として、以下式を満たす。
={K×β×(α−α)/α}+β
なお、βは、拡管前の伝熱管11の最小管内径であり、α1は、拡管前の伝熱管11の外径であり、α2は、拡管後の伝熱管11の外径である。
The diameter D 2 (preliminary pipe expansion end diameter D 2 ) of the preliminary pipe expansion end portion 3 b that becomes the boundary between the preliminary pipe expansion portion 6 A and the main pipe expansion portion 6 B is formed larger than the minimum inner diameter β of the heat transfer tube 11. Therefore, the minimum inner diameter portion of the heat transfer tube 11 (that is, the top portion of the inner fin 12) does not contact the preliminary tube expansion portion 6A and does not contact the main tube expansion portion 6B.
Also, pre-expanded tube ends diameter D 2 is the pre-expanded tube coefficient K as 0.45 to 0.65, satisfying the following equation.
D 2 = {K × β × (α 2 −α 1 ) / α 1 } + β
Β is the minimum tube inner diameter of the heat transfer tube 11 before the tube expansion, α1 is the outer diameter of the heat transfer tube 11 before the tube expansion, and α2 is the outer diameter of the heat transfer tube 11 after the tube expansion.

予備拡管係数Kを大きくすると予備拡管終了径Dが大きくなる。これに伴い、前面拡管部6において、予備拡管部6Aが相対的に大きくなり、主拡管部6Bが相対的に小さくなる。予備拡管部6Aは曲率半径Rを小さく形成されているため、予備拡管部6Aが相対的に大きくなることで、内面フィン12の倒れが顕著となる虞がある。
反対に、予備拡管係数Kを小さくすると予備拡管終了径D2が小さくなる。これに伴い、前面拡管部6において、予備拡管部6Aが相対的に小さくなり、主拡管部6Bが相対的に大きくなる。主拡管部6Bは曲率半径Rを大きく形成されているため、主拡管部6Bが相対的に大きくなることで、拡管時の初期拡管荷重が大きくなり伝熱管11が座屈する虞がある。
予備拡管係数Kを0.45以上、0.65以下とすることで、内面フィン12の倒れ及び伝熱管11の座屈を同時に抑制できる。
Preliminary expanded tube ends diameter D 2 is increased by increasing the pre-expanded tube coefficient K. Along with this, in the front expanded portion 6, the preliminary expanded portion 6A becomes relatively large, and the main expanded portion 6B becomes relatively small. A preliminary expanded portion 6A is formed smaller radius of curvature R 1, that the pre-expanded pipe portion 6A becomes relatively large, there is a possibility that the inclination of the inner surface fin 12 becomes remarkable.
On the contrary, when the preliminary expansion coefficient K is decreased, the preliminary expansion end diameter D2 is decreased. Accordingly, in the front expanded portion 6, the preliminary expanded portion 6A becomes relatively small, and the main expanded portion 6B becomes relatively large. The main expanded portion 6B because it is larger radius of curvature R 2, that the main expanded pipe portion 6B is relatively large, the initial tube expansion load increases heat transfer tube 11 of the tube expansion there is a possibility that buckling.
By setting the preliminary tube expansion coefficient K to 0.45 or more and 0.65 or less, the collapse of the inner fin 12 and the buckling of the heat transfer tube 11 can be suppressed at the same time.

ヘッド部3の最大径部3cより後方には、後面拡管部7が形成されている。後面拡管部7、曲率半径Rを有する一様な曲面である。
後面拡管部7は、拡管プラグ1を伝熱管11から引き抜く際に(引抜工程において)、弾性変形分だけ縮径した伝熱管11を再度径方向外側に押し広げて引抜をスムーズにさせる役割を果たす。加えて、把持治具によるクランプによって、縮径した伝熱管11の開口部11aの近傍を再度拡管する役割を果たす。
A rear pipe expanding portion 7 is formed behind the maximum diameter portion 3 c of the head portion 3. Rear expanded portion 7, a uniform curved surface having a radius of curvature R 3.
When the tube expansion plug 1 is pulled out from the heat transfer tube 11 (in the drawing step), the rear surface tube expansion portion 7 plays a role of smoothing the drawing by expanding the heat transfer tube 11 whose diameter is reduced by the elastic deformation again radially outward. . In addition, it plays a role of expanding the vicinity of the opening 11a of the heat transfer tube 11 having a reduced diameter again by clamping with a gripping jig.

この再度拡管される伝熱管の開口部11aは、拡管と縮径を経ているため、加工硬化が起こっている。したがって、後面拡管部7の曲率半径Rを適切に設定しない場合は、引抜工程において、伝熱管11に過度に引張応力が加わり、伝熱管11の破断が起こる。また、この引抜工程において、過度の引張応力が加わると、伝熱管11自身が伸長しその際に径方向に引けが生じる。即ち、拡管した伝熱管11が縮径されてしまう。
このような現象を防ぐために、後面拡管部7の曲率半径Rは、10mm以下とすることが好ましい。10mm以下とすることで、伝熱管11に過度な引張応力が加わることを抑制できる。
Since the opening 11a of the heat transfer tube to be expanded again has undergone expansion and contraction, work hardening has occurred. Therefore, if you do not set the radius of curvature R 3 of the rear expanded portion 7 properly, in drawing process, joined by excessive tensile stress in the heat transfer tube 11, the breaking of the heat transfer tube 11 takes place. Moreover, in this drawing process, when an excessive tensile stress is applied, the heat transfer tube 11 itself is stretched, and at that time, shrinkage occurs in the radial direction. That is, the expanded heat transfer tube 11 is reduced in diameter.
To prevent this phenomenon, the radius of curvature R 3 of the rear expanded portion 7 is preferably set to 10mm or less. By setting it as 10 mm or less, it can suppress that an excessive tensile stress is added to the heat exchanger tube 11.

図5(a)に示す拡管プラグ1において、軸部2は、強度の高い鋼材、例えば、JIS規定SCM435で示されるクロムモリブデン鋼からなる。また、ヘッド部3は超硬合金から一体形成されている。ヘッド部3は軸部2に対しカシメ加工により結合されているか、銀ろう等を用いたろう付け手段により結合されている。   In the pipe expansion plug 1 shown in FIG. 5A, the shaft portion 2 is made of a steel material having high strength, for example, chromium molybdenum steel shown by JIS regulation SCM435. Moreover, the head part 3 is integrally formed from the cemented carbide. The head portion 3 is coupled to the shaft portion 2 by caulking, or is coupled by brazing means using silver brazing or the like.

ヘッド部を構成する超硬合金としては、周期律表IVa、Va、VIa族元素の炭化物をFe、Co、Niなどの鉄系金属で焼結した超硬合金を用いることができる。一例として、WC−Co系合金、WC−TiC−Co系合金、WC−Ta−Co系合金、WC−TiC−Ta−Co系合金、WC−Ni系合金、WC−Ni−Cr系合金などを適宜用いることができる。
一例としてWC粒子にCoを5〜17質量%添加した超硬合金においてHRC85〜95の範囲を得ることができるので、本実施形態の拡管プラグ1の構成材料に適用することができる。上述の超硬合金としてJISV10、V20、V30、V40、V50、V60などで規定されている種類の超硬合金を利用することができる。
As the cemented carbide constituting the head portion, a cemented carbide obtained by sintering carbides of Group IVa, Va, and VIa group elements with an iron-based metal such as Fe, Co, or Ni can be used. For example, WC-Co alloy, WC-TiC-Co alloy, WC-Ta-Co alloy, WC-TiC-Ta-Co alloy, WC-Ni alloy, WC-Ni-Cr alloy, etc. It can be used as appropriate.
As an example, a range of HRC 85 to 95 can be obtained in a cemented carbide obtained by adding 5 to 17% by mass of Co to WC particles, and thus can be applied to the constituent material of the tube expansion plug 1 of the present embodiment. As the above-mentioned cemented carbide, a cemented carbide of the kind specified by JISV10, V20, V30, V40, V50, V60, etc. can be used.

また、図5(a)に示すように、拡管プラグ1は、ヘッド部3の外周面全面にダイヤモンドライクカーボン皮膜5が形成されていても良い。ダイヤモンドライクカーボン皮膜5を形成する場合には、その膜厚は、0.5μm以上3.0μm以下の範囲であることが好ましい。ダイヤモンドライクカーボン皮膜5の膜厚が0.5μm未満であると、アルミニウムの凝集抑制効果が低下し、拡管時に拡管プラグ1に対するアルミニウムの凝着が生じ易くなる。また、ダイヤモンドライクカーボン皮膜5の膜厚が3.0μmを超えるようであると、ダイヤモンドライクカーボン皮膜5の膜剥がれを生じ易くなる。
ダイヤモンドライクカーボン皮膜5の硬さについては、20GPa以上70GPa以下であることが好ましい。ダイヤモンドライクカーボン皮膜5の硬さが20GPa未満では耐摩耗性が低下して拡管プラグ1の寿命が短くなり、70GPaを超える硬さでは成膜自体が困難となる。
Further, as shown in FIG. 5A, the tube expansion plug 1 may have a diamond-like carbon film 5 formed on the entire outer peripheral surface of the head portion 3. When the diamond-like carbon film 5 is formed, the film thickness is preferably in the range of 0.5 μm to 3.0 μm. When the film thickness of the diamond-like carbon film 5 is less than 0.5 μm, the effect of suppressing the aggregation of aluminum is lowered, and the adhesion of aluminum to the tube expansion plug 1 is likely to occur during tube expansion. Further, when the film thickness of the diamond-like carbon film 5 exceeds 3.0 μm, the diamond-like carbon film 5 is likely to be peeled off.
The hardness of the diamond-like carbon film 5 is preferably 20 GPa or more and 70 GPa or less. When the hardness of the diamond-like carbon film 5 is less than 20 GPa, the wear resistance is reduced and the life of the tube expansion plug 1 is shortened, and when the hardness is more than 70 GPa, the film formation itself is difficult.

また、ダイヤモンドライクカーボン皮膜5の臨界剥離荷重は、5N以上であることが好ましい。ダイヤモンドライクカーボン皮膜5の臨界剥離荷重が5N未満では、皮膜の剥離が起こり易くなり、拡管プラグ1の寿命が短くなる。また、ダイヤモンドライクカーボン皮膜5の臨界膜厚荷重が30N以上であれば、より長い距離の拡管を施してもアルミニウムの凝着を生じ難い。   Further, the critical peel load of the diamond-like carbon film 5 is preferably 5N or more. When the critical peel load of the diamond-like carbon film 5 is less than 5N, the film is easily peeled and the life of the tube expansion plug 1 is shortened. Further, when the critical film thickness load of the diamond-like carbon film 5 is 30 N or more, it is difficult for aluminum to adhere even if the tube is expanded for a longer distance.

拡管プラグ1とともに拡管時に用いる潤滑油は、特に図示はしていないが、引火点100℃以下、動粘度1.0mm/S(at40℃)以上の潤滑油を用いることが好ましい。
この条件に用いることができる潤滑油として例示するならば、ダフニーパンチオイルAF−2A(出光興産製:動粘度1.37mm/S)を挙げることができる。
Although the lubricating oil used at the time of pipe expansion together with the pipe expansion plug 1 is not particularly illustrated, it is preferable to use a lubricating oil having a flash point of 100 ° C. or lower and a kinematic viscosity of 1.0 mm 2 / S (at 40 ° C.) or higher.
If it illustrates as a lubricating oil which can be used for this condition, Daphne punch oil AF-2A (Idemitsu Kosan make: kinematic viscosity 1.37mm < 2 > / S) can be mentioned.

以下、実施例を示しつつ本発明を更に詳細に説明するが、本発明はこれらの実施例に限定されるものではない。   EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated further in detail, this invention is not limited to these Examples.

(試験1)
拡管プラグの前面拡管部と、初期拡管荷重及び内面フィンの倒れについて試験1として調査した。
図5(a)、(b)に示す拡管プラグを数種類用意した。なお、拡管プラグのヘッド部は、VM40相当の超硬合金(HRA90)からなり、軸部は、JIS規定SCM435からなる。これらの拡管プラグの後面拡管部は、曲率半径7.5mmである。
(Test 1)
Test 1 was conducted on the front pipe expansion portion of the pipe expansion plug, the initial pipe expansion load, and the inner fin collapse.
Several types of tube expansion plugs shown in FIGS. 5A and 5B were prepared. The head portion of the tube expansion plug is made of cemented carbide (HRA90) equivalent to VM40, and the shaft portion is made of JIS standard SCM435. The rear surface expanded portion of these expanded plugs has a curvature radius of 7.5 mm.

これらの拡管プラグによって拡管される伝熱管として、図3(a)、(b)に示すような内面フィンが長手方向に対し直線状に形成された伝熱管を数種類用意した。また、この伝熱管はJIS3003合金からなる。
用意した拡管プラグを用いて、伝熱管の拡管工程を行った。拡管の際、伝熱管を潤滑油(ダフニーパンチオイルAF−2A:出光興産製:動粘度1.37mm/S)に浸漬後、直ちに拡管した。拡管時の拡管プラグの挿入速度は、500mm/minとした。
拡管プラグ、及び伝熱管の組み合わせをNo.1〜No.30として表1にまとめる。なお、表1において、外径拡管率とは、αを拡管前の伝熱管の外径、αを拡管後の伝熱管の外径とし、以下の式で百分率として表される。
100×(α−α)/α
このような拡管工程の結果として生じた、初期拡管荷重、安定拡管荷重、内面フィンの減少率を表2に示す。なお、安定拡管荷重とは、図7に示すように、拡管荷重が安定した領域の荷重を意味する。
As heat transfer tubes expanded by these tube expansion plugs, several types of heat transfer tubes having inner fins formed linearly in the longitudinal direction as shown in FIGS. The heat transfer tube is made of JIS3003 alloy.
Using the prepared tube expansion plug, the tube expansion process of the heat transfer tube was performed. During the expansion, the heat transfer tube was immersed in a lubricating oil (Daphney punch oil AF-2A: manufactured by Idemitsu Kosan Co., Ltd .: kinematic viscosity 1.37 mm 2 / S) and immediately expanded. The insertion speed of the expansion plug during expansion was 500 mm / min.
The combination of expansion pipe and heat transfer tube is No. 1-No. 30 is summarized in Table 1. In Table 1, the outer diameter tube expansion rate is expressed as a percentage in the following equation, with α 1 being the outer diameter of the heat transfer tube before tube expansion and α 2 being the outer diameter of the heat transfer tube after tube expansion.
100 × (α 2 −α 1 ) / α 1
Table 2 shows the initial tube expansion load, the stable tube expansion load, and the reduction rate of the inner fins, which are generated as a result of the tube expansion process. As shown in FIG. 7, the stable tube expansion load means a load in a region where the tube expansion load is stable.

Figure 2015123498
Figure 2015123498

Figure 2015123498
Figure 2015123498

初期拡管荷重が500N以上になると座屈が生じやすくなる。また、安定拡管荷重は450N以上になると、座屈が生じやすくなる。
内面フィンの減少率は、15%以上となると、内面フィンが倒れて熱交換効が下がり好ましくなる。また、内面フィンの倒れによって、外径が十分に拡管されないことがある。
If the initial tube expansion load is 500 N or more, buckling tends to occur. Further, when the stable tube expansion load is 450 N or more, buckling tends to occur.
When the reduction rate of the inner fins is 15% or more, the inner fins fall and the heat exchange effect decreases, which is preferable. In addition, the outer diameter may not be expanded sufficiently due to the fall of the inner fin.

表1、表2に示すように、様々な組み合わせの拡管プラグと伝熱管を用いた拡管工程のうち、No.1〜No.24の拡管工程においては、拡管荷重、及び内面フィンの高さ減少率を抑えることができていることがわかる。これに対して、No.25〜No.30の拡管工程においては、拡管荷重が高いか、又は内面フィンの減少率が大きくなっている。特に、No.26、28、29の拡管工程においては、拡管初期において座屈が生じた。
表1、表2に示す結果から、予備拡管部の曲率半径、主拡管部の曲率半径、予備拡管終了部の直径を適切に設定することで、拡管荷重を抑制しつつ、内面フィンの倒れを抑制可能であることを確認した。
また、伝熱管の底肉厚tに対する外径αの比(α/t)が、7以上16以下であり、内面フィンのフィンピッチiに対するフィン幅jの比(j/i)が、0.1以上0.7以下である場合に、より好ましい拡管工程を行うことができることが確認された。
As shown in Table 1 and Table 2, among the tube expansion steps using various combinations of tube expansion plugs and heat transfer tubes, No. 1 was used. 1-No. It can be seen that in the tube expansion process of 24, the tube expansion load and the height reduction rate of the inner surface fins can be suppressed. In contrast, no. 25-No. In 30 pipe expansion processes, the pipe expansion load is high or the reduction rate of the inner fins is large. In particular, no. In the tube expansion process of Nos. 26, 28, and 29, buckling occurred at the initial stage of tube expansion.
From the results shown in Tables 1 and 2, by appropriately setting the radius of curvature of the pre-expanded portion, the radius of curvature of the main expanded portion, and the diameter of the end portion of the pre-expanded tube, the inner fin collapses while suppressing the expansion load. It was confirmed that suppression was possible.
Further, the ratio (α 1 / t) of the outer diameter α 1 to the bottom wall thickness t of the heat transfer tube is 7 or more and 16 or less, and the ratio (j / i) of the fin width j to the fin pitch i of the inner surface fin is It was confirmed that a more preferable tube expansion process can be performed when the ratio is 0.1 or more and 0.7 or less.

(試験2)
次に、拡管プラグの後面拡管部と、初期拡管荷重及び内面フィンの倒れについて試験2として調査した。
図5(a)、(b)に示す拡管プラグであって、後面拡管部の曲率半径が異なる拡管プラグを数種類用意した。これらの拡管プラグは、予備拡管部の曲率半径が7mm、主拡管部の曲率半径が22mm、予備拡管終了径が5.57mm、最大径部の直径が5.86mmである。ヘッド部及び軸部の材質は、上述の試験1と同等である。
これらの拡管プラグによって拡管される伝熱管として、図3(a)、(b)に示すような内面フィンが長手方向に対し直線状に形成されJIS3003合金からなる伝熱管を用意した。これらの伝熱管の拡管前の最小内径は、5.4mm、外径は、7.0mm、底肉厚は、0.5mm、外径/底肉厚は、14.0、フィン幅は、0.15mm、フィンピッチは、0.38mm、フィンピッチ/フィン幅は、0.4、内面フィンの数は、50個である。
用意した拡管プラグを用いて、伝熱管の拡管工程を行った結果をNo.31〜No.34として表1にまとめる。なお、拡管後の伝熱管の外径は、7.4mmとなっていた。
拡管工程は、押込み式の拡管工程後に把持治具により伝熱管の開口部をクランプし、次いで吊下げ式の拡管工程、引抜工程を順次行った。クランプにより、伝熱管の開口部は、外径7.0mmに縮径されており、引抜工程において後面拡管部により再度拡管されている。
(Test 2)
Next, the rear surface expanded portion of the expanded tube plug, the initial expanded tube load, and the collapse of the inner fin were investigated as Test 2.
Several types of tube expansion plugs shown in FIGS. 5A and 5B, each having a different radius of curvature of the rear surface tube expansion portion, were prepared. These expanded pipes have a radius of curvature of the preliminary expanded portion of 7 mm, a radius of curvature of the main expanded portion of 22 mm, an end diameter of the expanded preliminary tube of 5.57 mm, and a diameter of the maximum diameter portion of 5.86 mm. The material of the head part and the shaft part is the same as in Test 1 described above.
As heat transfer tubes expanded by these tube expansion plugs, heat transfer tubes made of JIS3003 alloy having inner fins formed linearly in the longitudinal direction as shown in FIGS. 3A and 3B were prepared. These tubes have a minimum inner diameter of 5.4 mm, an outer diameter of 7.0 mm, a bottom wall thickness of 0.5 mm, an outer diameter / bottom wall thickness of 14.0, and a fin width of 0 mm. .15 mm, fin pitch is 0.38 mm, fin pitch / fin width is 0.4, and the number of internal fins is 50.
The result of the expansion process of the heat transfer tube using the prepared expansion plug is No. 31-No. 34 is summarized in Table 1. In addition, the outer diameter of the heat transfer tube after the tube expansion was 7.4 mm.
In the tube expansion process, the opening portion of the heat transfer tube was clamped by a holding jig after the push-in tube expansion step, and then the hanging tube expansion step and the drawing step were sequentially performed. The opening of the heat transfer tube is reduced to an outer diameter of 7.0 mm by the clamp, and is expanded again by the rear surface expanded portion in the drawing process.

Figure 2015123498
Figure 2015123498

表3に示すように、複数の拡管プラグを用いた拡管工程のうち、No.31においては、引抜工程時に、伝熱管の開口部付近で非常に大きな引抜力が生じ、伝熱管に破断が生じた。
また、No.32においては、引抜時の抵抗で伝熱管が長手方向に延ばされ、それに伴い引けが生じた(伝熱管の外径が小さくなった)。これにより、伝熱管が全長に亘り外径7.35mmとなっていた。これに対して、No.33、No.34の拡管工程においては、正常に引抜工程が行われた。
試験2の結果から、後面拡管部の曲率半径を10mm以上とすることで、引抜時に伝熱管に過度な引張応力が加わることがないことが確認された。
As shown in Table 3, among tube expansion processes using a plurality of tube expansion plugs, In No. 31, during the drawing process, a very large drawing force was generated near the opening of the heat transfer tube, and the heat transfer tube was broken.
No. In No. 32, the heat transfer tube was extended in the longitudinal direction due to the resistance at the time of drawing, and the shrinkage occurred accordingly (the outer diameter of the heat transfer tube was reduced). As a result, the heat transfer tube had an outer diameter of 7.35 mm over the entire length. In contrast, no. 33, no. In the tube expansion process 34, the drawing process was normally performed.
From the result of Test 2, it was confirmed that an excessive tensile stress was not applied to the heat transfer tube during drawing by setting the curvature radius of the rear surface expanded portion to 10 mm or more.

以上に、本発明の様々な実施形態を説明したが、各実施形態における各構成及びそれらの組み合わせ等は一例であり、本発明の趣旨から逸脱しない範囲内で、構成の付加、省略、置換、及びその他の変更が可能である。また、本発明は実施形態によって限定されることはない。   Although various embodiments of the present invention have been described above, each configuration in each embodiment and combinations thereof are examples, and addition, omission, replacement, and configuration of configurations are within the scope not departing from the spirit of the present invention. And other changes are possible. Further, the present invention is not limited by the embodiment.

1…拡管プラグ、2…軸部、3…ヘッド部、3a…先端部、3b…予備拡管終了部、3c…最大径部、3d…後端部、5…ダイヤモンドライクカーボン皮膜、6…前面拡管部、6A…予備拡管部、6B…主拡管部、7…後面拡管部、11、20…伝熱管、11a…開口部、12、22…内面フィン、14、23…フィン溝、15…フィン材(放熱フィン)、15a…挿通孔、D…先端部の直径、D…予備拡管終了径、D…最大径部の直径、K…予備拡管係数、R…予備拡管部の曲率半径、R…主拡管部の曲率半径、R…後面拡管部の曲率半径、h…フィンの高さ、i…フィンピッチ、j…フィン幅、t…底肉厚、α…拡管前外径、α…拡管後外径、β…最小内径 DESCRIPTION OF SYMBOLS 1 ... Tube expansion plug, 2 ... Shaft part, 3 ... Head part, 3a ... Tip part, 3b ... Pre-expansion end part, 3c ... Maximum diameter part, 3d ... Rear end part, 5 ... Diamond-like carbon film, 6 ... Front pipe expansion 6A ... Preliminary tube expansion portion, 6B ... Main tube expansion portion, 7 ... Rear surface tube expansion portion, 11, 20 ... Heat transfer tube, 11a ... Opening portion, 12, 22 ... Inner surface fins, 14, 23 ... Fin groove, 15 ... Fin material (Radiating fin), 15a: insertion hole, D 1 ... diameter of the tip, D 2 ... diameter of the preliminary expansion end, D 3 ... diameter of the maximum diameter, K ... preliminary expansion coefficient, R 1 ... radius of curvature of the preliminary expansion , R 2 ... curvature radius of the main pipe expansion part, R 3 ... curvature radius of the rear pipe expansion part, h ... fin height, i ... fin pitch, j ... fin width, t ... bottom wall thickness, α 1 ... outside before pipe expansion Diameter, α 2 ... Outer diameter after tube expansion, β ... Minimum inner diameter

Claims (3)

所定間隔に平行に並設する複数の放熱フィンに形成された挿通孔に、内周面に複数の内面フィンが形成された伝熱管を通し拡管することで前記放熱フィンに密着させるために、前記伝熱管に挿入する拡管プラグであって、
軸部と、その先端側に形成されるヘッド部と、を有し、
前記ヘッド部は、その横断面が先端部から最大径部まで徐々に直径を大きくする略円形状であり、先端部から最大径部の間に、滑らかに接続される予備拡管部と主拡管部とを備え、
前記予備拡管部は、前記伝熱管の最小管内径より小径の先端部から前記最小管内径より大径の予備拡管終了部までを5mm以上7.9mm以下の曲率半径で接続し、
前記主拡管部は、前記予備拡管終了部から前記最大径部までを20.1mm以上30mm以下の曲率半径で接続し、
前記予備拡管終了部の直径である予備拡管終了径が、以下の下記式で表されることを特徴とする拡管プラグ。
={K×β×(α−α)/α}+β
ただし、Dは、予備拡管終了径であり、
Kは0.45以上0.65以下の予備拡管係数であり、
βは、拡管前の前記伝熱管の最小管内径であり、
αは、拡管前の前記伝熱管の外径であり、
αは、拡管後の前記伝熱管の外径である。
In order to closely adhere to the heat radiating fins by expanding the heat transfer tube having a plurality of inner surface fins formed on the inner peripheral surface through the insertion holes formed in the plurality of heat radiating fins arranged in parallel in a predetermined interval, A tube expansion plug to be inserted into the heat transfer tube,
A shaft portion, and a head portion formed on the tip side thereof,
The head portion has a substantially circular shape whose cross section gradually increases in diameter from the tip portion to the maximum diameter portion, and a preliminary tube expansion portion and a main tube expansion portion that are smoothly connected between the tip portion and the maximum diameter portion. And
The pre-expanded portion connects a tip portion having a diameter smaller than the minimum tube inner diameter of the heat transfer tube to a pre-expansion end portion having a diameter larger than the minimum tube inner diameter with a radius of curvature of 5 mm or more and 7.9 mm or less,
The main expanded portion connects the preliminary expanded end portion to the maximum diameter portion with a radius of curvature of 20.1 mm to 30 mm,
A tube expansion plug, wherein the tube expansion end diameter, which is the diameter of the tube expansion end portion, is expressed by the following equation.
D 2 = {K × β × (α 2 −α 1 ) / α 1 } + β
However, D 2 is a pre-expanded tube end diameter,
K is a preliminary expansion coefficient of 0.45 or more and 0.65 or less,
β is the minimum tube inner diameter of the heat transfer tube before expansion,
α 1 is the outer diameter of the heat transfer tube before expansion,
α 2 is the outer diameter of the heat transfer tube after tube expansion.
前記伝熱管が、アルミニウム又はアルミニウム合金からなり、
拡管前の前記伝熱管の底肉厚tに対する外径αの比(α/t)が、7以上16以下であり、
拡管前の前記内面フィンのフィンピッチiに対するフィン幅jの比(j/i)が、0.1以上0.7以下であることを特徴とする請求項1に記載の拡管プラグ。
The heat transfer tube is made of aluminum or an aluminum alloy,
The ratio (α 1 / t) of the outer diameter α 1 to the bottom wall thickness t of the heat transfer tube before expansion is 7 or more and 16 or less,
2. The tube expansion plug according to claim 1, wherein a ratio (j / i) of a fin width j to a fin pitch i of the inner surface fin before tube expansion is 0.1 or more and 0.7 or less.
前記最大径部と当該最大径部より小径の後端部の間に後面拡管部を有し、
前記後面拡管部は、前記最大径部から前記後端部までを10mm以下の曲率半径で接続することを特徴とする請求項1又は2に記載の拡管プラグ。
Between the maximum diameter portion and the rear end portion having a smaller diameter than the maximum diameter portion, there is a rear surface expanded portion,
The tube expansion plug according to claim 1 or 2, wherein the rear surface tube expansion portion connects the maximum diameter portion to the rear end portion with a curvature radius of 10 mm or less.
JP2013272103A 2013-12-27 2013-12-27 Expansion plug Expired - Fee Related JP6238063B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2013272103A JP6238063B2 (en) 2013-12-27 2013-12-27 Expansion plug

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2013272103A JP6238063B2 (en) 2013-12-27 2013-12-27 Expansion plug

Publications (2)

Publication Number Publication Date
JP2015123498A true JP2015123498A (en) 2015-07-06
JP6238063B2 JP6238063B2 (en) 2017-11-29

Family

ID=53534625

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2013272103A Expired - Fee Related JP6238063B2 (en) 2013-12-27 2013-12-27 Expansion plug

Country Status (1)

Country Link
JP (1) JP6238063B2 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024058263A1 (en) * 2022-09-16 2024-03-21 ダイキン工業株式会社 Method for manufacturing heat exchanger
JP7492181B2 (en) 2022-09-16 2024-05-29 ダイキン工業株式会社 Heat exchanger manufacturing method

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11898422B2 (en) 2020-11-03 2024-02-13 Saudi Arabian Oil Company Diamond coating on the cone for expandable tubulars

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH085278A (en) * 1994-06-20 1996-01-12 Mitsubishi Shindoh Co Ltd Heat transfer tube with inner surface grooves
JP2005288502A (en) * 2004-03-31 2005-10-20 Kobelco & Materials Copper Tube Inc Tube expanding tool and method for expanding tube using the same
JP2011208823A (en) * 2010-03-29 2011-10-20 Furukawa Electric Co Ltd:The Method of manufacturing heat exchanger
JP4913371B2 (en) * 2004-10-04 2012-04-11 古河電気工業株式会社 Manufacturing method of heat exchanger
US20130298632A1 (en) * 2011-01-24 2013-11-14 Eric Konkle Expansion bullet for heat exchanger tube

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH085278A (en) * 1994-06-20 1996-01-12 Mitsubishi Shindoh Co Ltd Heat transfer tube with inner surface grooves
JP2005288502A (en) * 2004-03-31 2005-10-20 Kobelco & Materials Copper Tube Inc Tube expanding tool and method for expanding tube using the same
JP4913371B2 (en) * 2004-10-04 2012-04-11 古河電気工業株式会社 Manufacturing method of heat exchanger
JP2011208823A (en) * 2010-03-29 2011-10-20 Furukawa Electric Co Ltd:The Method of manufacturing heat exchanger
US20130298632A1 (en) * 2011-01-24 2013-11-14 Eric Konkle Expansion bullet for heat exchanger tube

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024058263A1 (en) * 2022-09-16 2024-03-21 ダイキン工業株式会社 Method for manufacturing heat exchanger
JP7492181B2 (en) 2022-09-16 2024-05-29 ダイキン工業株式会社 Heat exchanger manufacturing method

Also Published As

Publication number Publication date
JP6238063B2 (en) 2017-11-29

Similar Documents

Publication Publication Date Title
US2929408A (en) Fin construction
JP5649715B2 (en) Heat exchanger, refrigerator equipped with this heat exchanger, and air conditioner
JP2005288502A (en) Tube expanding tool and method for expanding tube using the same
JP6238063B2 (en) Expansion plug
JP2007271123A (en) Inner face-grooved heat transfer tube
EP2738506A2 (en) Heat exchanger and method of manufacturing the same
US20160361749A1 (en) Heat exchanger manufacturing method and diameter enlargement tool
JP2015150566A (en) Tube expansion plug
CN102822616B (en) The manufacture method of heat exchanger
JP2010214404A (en) Method for manufacturing heat exchanger, and air-conditioner using the heat exchanger
US1787942A (en) Manufacture of heat-exchange apparatus
JP6521424B2 (en) Expansion pipe and design method for expansion pipe
JP6288581B2 (en) Method of expanding aluminum or aluminum alloy heat transfer tubes
WO2014010387A1 (en) Tube expansion plug
JP2013142454A (en) Pipe joint, heat exchanger, and method of manufacturing heat exchanger
US20200088470A1 (en) Heat exchanger, heat exchanger manufacturing method, and air-conditioner including heat exchanger
JP6958238B2 (en) How to manufacture heat exchangers and heat exchangers
JP2014105951A (en) Heat exchanger
JP2013092335A (en) Aluminum capillary tube for heat exchanger, and heat exchanger using the same
JP6312314B2 (en) Heat transfer element tube and method of manufacturing heat transfer element tube
CN217303714U (en) System for installing an expandable tubular in a heat exchanger, expandable tubular and expansion bullet
WO2017080269A1 (en) Heat exchanger and heat exchange tube
JP6294709B2 (en) Heat transfer tube with inner groove for evaporator
WO2018097044A1 (en) Heat exchanger and method for manufacturing heat exchanger
WO2010016198A1 (en) Grooved tube for heat exchanger

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20161124

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20170921

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20171003

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20171018

R150 Certificate of patent or registration of utility model

Ref document number: 6238063

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

LAPS Cancellation because of no payment of annual fees