JPH0814786A - Heat exchanger tube with inner surface groove - Google Patents

Abstract

PURPOSE:To provide a heat exchanger tube with an inner surface groove which is excellent in heating performance and easy to work and high in productivity, and what is more, which is capable of laying out fins uniformly in a tube expansion process which fixes the fins with the tubes. CONSTITUTION:In inner surface grooved heat exchanger tubes which has a spiral groove continuous with the inner surfaces of tubes and whose outside diameter is defined as D, the following properties of the tubes are set: The ratio S1/S2 between a cross section area of the groove S1 and a cross section area of a crest between the grooves S2 in a cross section area which intersects with a tube axis at a right angle ranges from 2.5 to 4.5. The ratio h/D between a groove depth h and an outside diameter of tube D ranges from 0.008 to 0.16. A crest angle alpha produced by an extension line of a slope on both sides of the crest ranges from 40 to 60 deg.. The average roughness Ra of the central line of the tube outer surface in the longitudinal direction is 0.8mu and below.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は空気調和機及び冷凍機等
の熱交換器の中で管内流体が相変化する熱交換器等に使
用され内面に螺旋状の溝が設けられた内面溝付伝熱管に
関し、特に伝熱管の外周面にフィンが取り付けられた空
気熱交換器に使用するのに好適の内面溝付伝熱管に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for heat exchangers such as air conditioners and refrigerators in which the fluid in the pipe changes phase, and is provided with an inner groove provided with a spiral groove on the inner surface. The present invention relates to a heat transfer tube, and more particularly to an inner grooved heat transfer tube suitable for use in an air heat exchanger having fins attached to the outer peripheral surface of the heat transfer tube.

【０００２】[0002]

【従来の技術】一般的に、空調機器等に使用される熱交
換器には、冷凍能力を向上させるために管内面に連続す
る螺旋状の溝が設けられた内面溝付伝熱管が使用されて
いる。内面溝付伝熱管の溝形状としては、三角形、台形
及び半円形等があるが、一般的には台形又は三角形状の
溝が採用されている。2. Description of the Related Art Generally, a heat exchanger used for an air conditioner or the like uses an inner grooved heat transfer tube provided with a continuous spiral groove on the inner surface of the tube in order to improve refrigerating capacity. ing. The groove shape of the inner surface grooved heat transfer tube includes a triangle, a trapezoid, a semicircle, and the like, but generally a trapezoidal or triangular groove is adopted.

【０００３】この内面溝付伝熱管は、被加工管に対し、
球を使用した転造加工（溝付加工）を施して所定の溝形
状を形成することにより製造されている（特開昭６０−
１８７４２５号）。図７は、この転造加工方法を示す模
式図である。先ず、被加工管１２を引抜きダイス１４ａ
に通して縮径し、次に球１３で管１２の外周面を転圧す
ることにより、管１２の外周面に螺旋状に凹凸を形成す
る。次いで、この管１２を仕上げダイス１４ｂに通して
管１２に空引きを施す。このような転造加工において
は、管１２の外周面に球１３を押圧してその外周面に螺
旋状の凹凸を形成するが、凹凸のピッチをＰ、凹凸の高
低差をｅ、管１２を転圧した球１３の外径をｄとする
と、凹凸の高低差ｅは下記数式１で表される。This internal grooved heat transfer tube is
It is manufactured by performing a rolling process (grooving process) using a sphere to form a predetermined groove shape (JP-A-60-
187425). FIG. 7 is a schematic diagram showing this rolling processing method. First, the pipe 12 to be processed is drawn out with a die 14a.
To reduce the diameter, and then roll the outer peripheral surface of the tube 12 with the ball 13 to form spiral irregularities on the outer peripheral surface of the tube 12. Next, the tube 12 is passed through a finishing die 14b to perform an empty drawing on the tube 12. In such a rolling process, the sphere 13 is pressed against the outer peripheral surface of the tube 12 to form a spiral unevenness on the outer peripheral surface. The pitch of the unevenness is P, the height difference of the unevenness is e, and the tube 12 is When the outer diameter of the rolled ball 13 is d, the height difference e of the unevenness is expressed by the following mathematical formula 1.

【０００４】[0004]

【数１】ｅ＝Ｐ²／（４ｄ） また、加工部における被加工管１２の相対速度をｖ、球
１３の個数をｓ、球１３が被加工管１２の周囲を公転す
る速度をｎとすると、ピッチＰは下記数式２で表され
る。[Equation 1] e = P ² / (4d) Further, let v be the relative velocity of the pipe 12 to be machined in the machining portion, s be the number of spheres 13 and n be the velocity at which the sphere 13 revolves around the pipe 12 to be machined. Then, the pitch P is expressed by Equation 2 below.

【０００５】[0005]

【数２】Ｐ＝ｖ・ｓ・ｎ 管１２をその材料移動方向の下流側にある仕上げダイス
１４ｂを通過させ、管１２の外周面を平坦化すると共
に、球１３が形成した凹凸の凸部を管１２内面に転移さ
せて管１２の内面に溝を形成する。## EQU00002 ## P = v.s.n The tube 12 is passed through a finishing die 14b located on the downstream side in the material movement direction to flatten the outer peripheral surface of the tube 12 and to form uneven projections formed by the balls 13. Is transferred to the inner surface of the tube 12 to form a groove on the inner surface of the tube 12.

【０００６】従来、内面溝付伝熱管の伝熱性能を向上さ
せることにより、熱交換器の高性能化を図ることが検討
されている。即ち、内面溝付伝熱管内に形成されている
溝の溝数、溝深さ、ねじれ角及び溝と溝との間の山部の
山頂角等の形状因子を適正化して、内面溝付伝熱管の伝
熱性能を向上させている。この場合に、内面溝付伝熱管
の伝熱性能を向上させるために、溝数を多くすること、
溝深さを深くすること、山頂角を小さくすること及びね
じれ角を大きくすることが有効である。[0006] Conventionally, it has been considered to improve the heat transfer performance of a heat transfer tube with an inner groove to improve the performance of the heat exchanger. That is, the shape factors such as the number of grooves formed in the inner surface grooved heat transfer tube, the groove depth, the helix angle, and the crest angle of the crest between the grooves are optimized, and the inner surface grooved heat transfer tube is adjusted. The heat transfer performance of the heat tube is improved. In this case, in order to improve the heat transfer performance of the inner surface grooved heat transfer tube, increase the number of grooves,
It is effective to increase the groove depth, decrease the peak angle and increase the helix angle.

【０００７】例えば、特開昭６０−１４２１９５号に
は、内面溝付伝熱管の管内径Ｄ_i と溝深さＨ_f との比Ｄ
_i ／Ｈ_f が０．０２〜０．０３、ねじれ角が７〜３０
°、溝の断面積Ｓと溝深さＨ_f との比Ｓ／Ｈ_f が０．２
〜０．３、山頂角が３０〜６０°の形状のものが開示さ
れている。また、特開昭５４−８５４６１号には内面溝
付伝熱管の溝深さが０．２〜０．５ｍｍ、溝ピッチが
０．３〜１．５ｍｍ、平均溝幅Ｗ₁ 及び平均山幅Ｗ₂ が
Ｗ₁ ≧Ｗ₂ の関係を満たすものが開示されている。For example, in Japanese Patent Laid-Open No. 60-142195, a ratio D of the inner diameter D _{i of a} heat transfer tube with an inner groove to the groove depth H _f is given.
_i / H _f is 0.02 to 0.03, and twist angle is 7 to 30
°, the ratio S / H _f the groove cross-sectional area S and groove depth H _f 0.2
.About.0.3 and a peak angle of 30 to 60.degree. Are disclosed. Further, in JP-A-54-85461, the groove depth of the heat transfer tube with inner groove is 0.2 to 0.5 mm, the groove pitch is 0.3 to 1.5 mm, the average groove width W ₁ and the average crest width W. ₂ satisfy the relationship of W ₁ ≧ W ₂ is disclosed.

【０００８】図８は空気熱交換器の製造工程における内
面溝付伝熱管とアルミニウムフィンとの組立方法を示す
模式図である。この空気熱交換器の組立ては、先ず上述
したような内面溝付伝熱管１５をヘアピン状に曲げ、内
面溝付伝熱管１５の外径より若干大きい径で開孔部１６
ａを設けたアルミニウムフィン１６に挿入し、次に略球
状の先端部を有する拡管用工具１７を内面溝付伝熱管１
５の内側に通し、伝熱管１５を拡管して、フィン１６と
伝熱管１５とを固着させる。FIG. 8 is a schematic view showing an assembling method of the inner surface grooved heat transfer tube and the aluminum fin in the manufacturing process of the air heat exchanger. In assembling this air heat exchanger, first, the inner grooved heat transfer tube 15 as described above is bent into a hairpin shape, and the opening portion 16 is formed with a diameter slightly larger than the outer diameter of the inner grooved heat transfer tube 15.
Inserted into the aluminum fin 16 provided with a, then the pipe expanding tool 17 having a substantially spherical tip portion is provided with the inner surface grooved heat transfer tube 1
5, the heat transfer tube 15 is expanded to fix the fins 16 to the heat transfer tube 15.

【０００９】近年、空調機においては、スペースの有効
活用の観点から壁掛型の室外機の採用が増加し、熱交換
器を含めた機器の軽量化が要求されている。また、機器
の製造コストを下げるために、熱交換器の生産性を向上
させることが要求されている。In recent years, in air conditioners, the adoption of wall-mounted outdoor units has increased from the viewpoint of effective utilization of space, and there has been a demand for weight reduction of devices including heat exchangers. Further, in order to reduce the manufacturing cost of the equipment, it is required to improve the productivity of the heat exchanger.

【００１０】[0010]

【発明が解決しようとする課題】しかしながら、前述し
た従来の内面溝付伝熱管は、溝深さを深くし、溝数を可
及的に増加したものであり、内面溝付伝熱管の伝熱性能
を向上させようとすると、重量が増加してしまうという
問題点がある。また、従来の内面溝付伝熱管は山頂角を
小さくし、ねじれ角を大きくしているため、製造速度を
向上させようとすると、溝付加工時に管軸方向へのメタ
ルフローが大きくなると共に、管の半径方向へのメタル
フローが小さくなるため、溝の形成が困難になる。従っ
て、従来の内面溝付伝熱管の製造速度には限界がある。
更に、内面溝付伝熱管の溝深さを深くすると、管材の工
具に対する押圧力が大きくなり、潤滑油の膜切れが発生
する。その結果、潤滑不良で内面溝付伝熱管に焼付きが
発生し、山部にクラックが生じやすくなると共に、溝を
形成するためのプラグも破損しやすくなる。However, the above-mentioned conventional heat transfer tube with inner groove has a deep groove depth and the number of grooves is increased as much as possible. There is a problem that the weight is increased when the performance is improved. Further, the conventional grooved heat transfer tube with inner groove has a small crest angle and a large helix angle, so if it is attempted to improve the manufacturing speed, the metal flow in the tube axis direction becomes large during groove processing, Since the metal flow in the radial direction of the tube becomes small, it becomes difficult to form the groove. Therefore, there is a limit to the manufacturing speed of the conventional inner surface grooved heat transfer tube.
Furthermore, if the groove depth of the heat transfer tube with inner groove is increased, the pressing force of the pipe material against the tool increases, and the film of lubricating oil is broken. As a result, seizure occurs in the inner grooved heat transfer tube due to poor lubrication, cracks are likely to occur in the crests, and the plug for forming the groove is also easily damaged.

【００１１】このように、従来の内面溝付伝熱管は、伝
熱性能を向上させようとするほど製造が困難になるとい
う欠点がある。しかし、特開昭６２−１４２９９５号等
に開示された技術では、このような欠点に対する検討は
なされていない。As described above, the conventional heat transfer tube with the inner groove has a drawback that the manufacturing becomes difficult as the heat transfer performance is improved. However, the technique disclosed in Japanese Patent Laid-Open No. 62-142995 has not examined such a defect.

【００１２】例えば、特開昭６０−１４２１９５号に開
示された内面溝付伝熱管は、溝の断面積Ｓ₁ と山部断面
積Ｓ₂ との比Ｓ₁ ／Ｓ₂ は２〜４．５であるが、溝深さ
ｈと管外径Ｄとの比ｈ／Ｄが０．０１８より大きくなる
ため、伝熱管の加工時に前述したような溝形状の不良並
びに伝熱管と工具との焼付き及びプラグの欠けが生じや
すく、製造速度を大幅に低減する必要がある。また、溝
深さｈと管外径Ｄとの比ｈ／Ｄが０．０２１を超えてい
る特開昭５４−８５４６１号に開示された内面溝付伝熱
管にも同様の問題点がある。更に、このように溝深さｈ
と管外径Ｄとの比ｈ／Ｄが大きい場合は、転造加工時の
球の押圧よる凹凸が大きくなり、伝熱管外面の管軸方向
の中心線平均粗さＲａは１．２μｍ以上になる。この場
合に、内面溝付伝熱管の外周面の管軸方向の中心線平均
粗さＲａは、転造部の下流側にある仕上げダイスで抽伸
してもＲａは０．８μｍを超える。図９は、Ｒａが０．
８μｍを超えている伝熱管とフィンとの組立工程におけ
る問題点を示す模式図である。For example, in the heat transfer tube with internal groove disclosed in Japanese Patent Laid-Open No. 60-142195, the ratio S ₁ / S ₂ between the groove cross-sectional area S ₁ and the peak cross-sectional area S ₂ is ₂ to 4.5. However, since the ratio h / D between the groove depth h and the pipe outer diameter D is larger than 0.018, the groove shape is defective as described above during machining of the heat transfer tube and seizure between the heat transfer tube and the tool. Also, the plug is apt to be chipped, and it is necessary to greatly reduce the manufacturing speed. Further, the heat transfer tube with the inner groove having the ratio h / D of the groove depth h and the outer diameter D of the tube exceeding 0.021 has the same problem. Further, in this way, the groove depth h
When the ratio h / D between the pipe outer diameter D and the pipe outer diameter D is large, the unevenness due to the pressing of the balls during the rolling process becomes large, and the centerline average roughness Ra of the outer surface of the heat transfer pipe in the pipe axis direction becomes 1.2 μm or more. Become. In this case, the centerline average roughness Ra of the outer peripheral surface of the inner surface grooved heat transfer tube in the tube axis direction is such that Ra exceeds 0.8 μm even when drawn by a finishing die located downstream of the rolling portion. In FIG. 9, Ra is 0.
It is a schematic diagram which shows the problem in the assembly process of the heat transfer tube and fin which exceeds 8 micrometers.

【００１３】Ｒａが０．８μｍを超えていると、拡管に
伴い伝熱管１９がその軸方向に収縮する際にフィン１６
の一部が伝熱管１９に密着して移動し、フィン１６の間
隔が不揃いになる疎密部１８が発生する。このような疎
密部１８は、内面溝付伝熱管１９を高速で拡管した場合
に発生しやすいため、疎密部１８が発生した場合は拡管
の速度を落とす必要があり、熱交換器の生産性が大幅に
低下する。If Ra exceeds 0.8 μm, the fins 16 will contract when the heat transfer tube 19 contracts in the axial direction as the tube expands.
Part of the fins moves in close contact with the heat transfer tube 19 to generate the sparse and dense part 18 in which the intervals of the fins 16 are uneven. Such a dense portion 18 is likely to occur when the inner surface grooved heat transfer tube 19 is expanded at a high speed. Therefore, when the dense portion 18 occurs, it is necessary to reduce the expansion speed, and the productivity of the heat exchanger increases. Drastically reduced.

【００１４】一方、溝深さｈと管外径Ｄとの比ｈ／Ｄが
小さい場合には、内面溝付伝熱管の成型時の溝形状不良
及び拡管時のアルミニウムフィンの不揃いの発生は抑制
できるが、内面溝付伝熱管の伝熱性能が低下する。On the other hand, when the ratio h / D between the groove depth h and the pipe outer diameter D is small, the occurrence of defective groove shape at the time of molding the inner grooved heat transfer tube and unevenness of the aluminum fins at the time of expanding the tube is suppressed. However, the heat transfer performance of the heat transfer tube with inner groove is reduced.

【００１５】本発明はかかる問題点に鑑みてなされたも
のであって、伝熱性能が高いと共に、加工が容易であっ
て生産性が高く、更にフィンを接合して熱交換器を組立
てるための拡管時にフィンの相互間隔に不揃いが発生せ
ず、熱交換器の生産性を高めることができる内面溝付伝
熱管を提供することを目的とする。The present invention has been made in view of the above problems, and has high heat transfer performance, is easy to process and has high productivity, and is for assembling a heat exchanger by joining fins. It is an object of the present invention to provide a heat transfer tube with an inner groove, which does not cause unevenness in the mutual spacing of fins when expanding the tube and which can enhance the productivity of the heat exchanger.

【００１６】[0016]

【課題を解決するための手段】本発明に係る内面溝付伝
熱管は、管内面に連続する螺旋状の溝を有する管外径Ｄ
の内面溝付伝熱管において、管軸に直交する断面におけ
る溝の断面積Ｓ₁ と前記溝の間の山部の断面積Ｓ₂ との
比Ｓ₁ ／Ｓ₂ が２．５≦Ｓ₁ ／Ｓ₂ ≦４．５、前記溝の
深さｈと前記管外径Ｄとの比ｈ／Ｄが０．００８≦ｈ／
Ｄ≦０．０１６、前記山部の両斜面のなす山頂角αが４
０°≦α≦６０°の範囲にあり、管外面の管軸方向の中
心線平均粗さＲａがＲａ≦０．８μｍであることを特徴
とする。A heat transfer tube with an inner groove according to the present invention has a tube outer diameter D having a spiral groove continuous with the inner surface of the tube.
In the inner grooved heat transfer tube of _{No. 1} , the ratio S ₁ / S ₂ of the cross-sectional area S ₁ of the groove in the cross section orthogonal to the tube axis and the cross-sectional area S ₂ of the mountain portion between the grooves is 2.5 ≦ S ₁ / S ₂ ≦ 4.5, the ratio h / D between the groove depth h and the pipe outer diameter D is 0.008 ≦ h /
D ≦ 0.016, the summit angle α formed by both slopes of the mountain portion is 4
It is characterized in that it is in the range of 0 ° ≦ α ≦ 60 °, and the center line average roughness Ra of the outer surface of the tube in the tube axis direction is Ra ≦ 0.8 μm.

【００１７】[0017]

【作用】本願発明者等は、伝熱性能が高いと共に、加工
が容易であって生産性が高く、更に拡管時のフィンの不
揃いが発生しない内面溝付伝熱管を得るべく種々実験研
究を行った。その結果、内面溝付伝熱管の溝の断面積Ｓ
₁ と山部の断面積Ｓ₂ との比Ｓ₁ ／Ｓ₂ 、溝深さｈと管
外径Ｄとの比ｈ／Ｄ及び前記山部の山頂角αを所定の範
囲に規制することにより、従来と同程度の伝熱性能を維
持しつつ、伝熱管の軽量化が可能であり、更に生産性が
向上するとの知見を得た。また、管外面の管軸方向の中
心線平均粗さＲａを特定の値以下に規制することによ
り、拡管時のフィンの不揃いを防止でき、拡管速度を向
上させることができて、フィン接合時の生産性が向上す
るとの知見も得た。The present inventors have conducted various experiments and researches in order to obtain a heat transfer tube with an inner groove, which has high heat transfer performance, is easy to process and has high productivity, and does not cause uneven fins during pipe expansion. It was As a result, the cross-sectional area S of the groove of the inner surface grooved heat transfer tube
By restricting ₁ and a ratio S ₁ / S ₂ of the cross-sectional area S ₂ of the crest, the crest angle α of the ratio h / D and the crests of the groove depth h and the tube outer diameter D in a predetermined range , It was found that the heat transfer tube can be made lighter while maintaining the same heat transfer performance as the conventional one, and that the productivity is further improved. Further, by restricting the centerline average roughness Ra of the outer surface of the pipe in the pipe axis direction to a specific value or less, it is possible to prevent the fins from being uneven when expanding the pipe, improve the pipe expanding speed, and improve the pipe expanding speed. We also obtained the knowledge that productivity will improve.

【００１８】以下、溝の断面積Ｓ₁ と山部の断面積Ｓ₂
との比Ｓ₁ ／Ｓ₂ 、溝深さｈと管外径Ｄとの比ｈ／Ｄ及
び前記山部の山頂角αについて説明する。図１は内面溝
付伝熱管の溝形成工程を示す一部破断断面図である。図
１に示すように、内面溝付伝熱管の製造工程において
は、転造加工により管外面にピッチがＰｔ、凹凸の最大
高低差がＰｅの凸部１及び凹部２を形成し、その後仕上
げダイスに通すことにより、管外面４を平坦化すると共
に、管内面に凹凸を転写して、管内面に螺旋状に延びる
溝３を形成する。Below, the cross-sectional area S _{1 of the} groove and the cross-sectional area S _{2 of the} mountain portion
The ratio S ₁ / S _{2 of} the groove depth h and the ratio h / D of the groove depth h to the pipe outer diameter D and the crest angle α of the crest portion will be described. FIG. 1 is a partially cutaway cross-sectional view showing a groove forming step of an inner surface grooved heat transfer tube. As shown in FIG. 1, in a manufacturing process of a heat transfer tube with an inner groove, a convex portion 1 and a concave portion 2 having a pitch Pt and a maximum unevenness difference Pe of Pe are formed on the outer surface of the pipe by a rolling process, followed by finishing die. The outer surface 4 of the tube is flattened by passing through the inner surface of the tube, and the unevenness is transferred to the inner surface of the tube to form the groove 3 spirally extending on the inner surface of the tube.

【００１９】図２は、図１のＡ−Ａ線における断面の管
内面の溝３を示す模式図である。管１１の内面には例え
ば略三角形状の山部１０とこの山部１０に挟まれた溝３
とが設けられている。溝の断面積Ｓ₁ とは、図２に斜線
で示すように、隣接する山部１０の相互に対向する斜面
８ａ，８ｂと、これらの山部１０の頂点５を結ぶ線と、
溝底面６とにより囲まれた部分の面積をいう。また、山
部１０の断面積Ｓ₂ とは、斜面８ａ，８ｂと溝底面６の
延長線７とに囲まれた部分の面積をいう。更に、溝深さ
ｈとは、隣接する山部１０の頂点５を結ぶ線分から溝底
面６までの深さをいい、これは実質的に山部１０の高さ
と同一である。更にまた、山頂角αは、山部１０の両斜
面８ａ，８ｂの直線部分のなす角度をいう。更にまた、
管外径Ｄは、図１に示すように、仕上げダイスを通って
外周面が平坦化した伝熱管の外径をいう。なお、平面視
で管の中心軸と溝３とのなす角度をねじれ角θという。FIG. 2 is a schematic view showing the groove 3 on the inner surface of the pipe of the cross section taken along the line AA in FIG. The inner surface of the pipe 11 has, for example, a substantially triangular mountain portion 10 and a groove 3 sandwiched between the mountain portions 10.
Are provided. The cross-sectional area S _{1 of the} groove means, as shown by the diagonal lines in FIG. 2, the slopes 8 a and 8 b facing each other of the adjacent mountain portions 10 and a line connecting the vertices 5 of these mountain portions 10.
The area surrounded by the groove bottom surface 6 is referred to. Further, the cross-sectional area S ₂ of the mountain portion 10 refers to the area of a portion surrounded by the slopes 8a and 8b and the extension line 7 of the groove bottom surface 6. Further, the groove depth h means the depth from the line segment connecting the apexes 5 of the adjacent mountain portions 10 to the groove bottom surface 6, which is substantially the same as the height of the mountain portions 10. Furthermore, the peak angle α is an angle formed by the straight line portions of both slopes 8a and 8b of the mountain portion 10. Furthermore,
The tube outer diameter D is the outer diameter of the heat transfer tube whose outer peripheral surface is flattened through a finishing die as shown in FIG. The angle formed by the central axis of the tube and the groove 3 in plan view is called the twist angle θ.

【００２０】次に、本発明に係る内面溝付伝熱管の各数
値限定理由について説明する。Next, the reasons for limiting the numerical values of the heat transfer tube with the inner groove according to the present invention will be described.

【００２１】溝の断面積Ｓ₁ と山部の断面積Ｓ₂との比
Ｓ₁ ／Ｓ₂ 管軸に直交する断面において、溝の断面積Ｓ₁ と前記溝
の間の山部の断面積Ｓ₂ との比Ｓ₁ ／Ｓ₂ が２．５未満
であると、山部の断面積が溝に比して大きいため、内面
溝付伝熱管の重量が増加すると共に、溝の断面積が小さ
いため、溝に冷媒が滞留しやすくなり、その結果、冷媒
の液膜が厚くなって熱抵抗が増加し、内面溝付伝熱管の
伝熱性能が低下する。一方、溝と山部との断面積の比Ｓ
₁ ／Ｓ₂が４．５を超える場合は、溝付加工時に管軸方
向へのメタルフローが大きくなると共に、管の半径方向
へのメタルフローが小さくなり、十分な深さの溝が得ら
れない。また、各山部にかかる加工負荷が大きくなるた
め、溝付加工時に山部に亀裂が発生しやすくなる。製造
速度を大幅に低減することにより亀裂を回避することは
できるが、そうすると生産性が著しく低下する。従っ
て、溝と山部との断面積の比Ｓ₁ ／Ｓ₂ は２．５〜４．
５とすることが必要である。なお、断面積の比Ｓ₁ ／Ｓ
₂ は、３．０〜４．０であることがより一層好ましい。 The ratio of the sectional area S _{1 of the} groove to the sectional area S ₂ of the crest
If the ratio S ₁ / S ₂ between the cross-sectional area S ₁ of the groove and the cross-sectional area S ₂ of the crests between the grooves is less than 2.5 in the cross section orthogonal to the S ₁ / S ₂ tube axis, Since the cross-sectional area of the portion is larger than that of the groove, the weight of the heat transfer tube with internal groove increases, and the cross-sectional area of the groove is small, so that the refrigerant easily stays in the groove, and as a result, the liquid film of the refrigerant is formed. As the thickness increases, the thermal resistance increases, and the heat transfer performance of the internal grooved heat transfer tube decreases. On the other hand, the ratio S of the cross-sectional area between the groove and the peak
_{When 1} / S ₂ exceeds 4.5, the metal flow in the axial direction of the pipe increases during groove processing, and the metal flow in the radial direction of the pipe also decreases, resulting in a groove of sufficient depth. Absent. Further, since the machining load applied to each crest portion becomes large, cracks are likely to occur in the crest portion during groove forming. Although cracks can be avoided by significantly reducing the production rate, doing so significantly reduces productivity. Therefore, the cross-sectional area ratio S ₁ / S ₂ between the groove and the crest is _2.5 to 4.
It is necessary to set it to 5. The cross-sectional area ratio S ₁ / S
It is even more preferable that ₂ is 3.0 to 4.0.

【００２２】溝深さｈと管外径Ｄとの比ｈ／Ｄ 内面溝付伝熱管の溝深さｈと管外径Ｄとの比ｈ／Ｄが
０．００８未満の場合は、伝熱面積が十分ではなく、山
部による冷媒の攪乱効果が減少し、内面溝付伝熱管の伝
熱性能が減少する。一方、溝深さと管外径との比ｈ／Ｄ
が０．０１６を超えると、溝付加工時の管軸方向へのメ
タルフローが大きくなると共に、管の半径方向へのメタ
ルフローが小さくなり、深い溝を形成することが困難に
なる。また、この場合は、内面溝付伝熱管の各山部にか
かる加工負荷が大きくなるため、内面溝付伝熱管への溝
付加工時に山部に亀裂が発生しやすくなり、亀裂を回避
するためには製造速度を大幅に低減させる必要がある。
更に、内面溝付伝熱管の重量が増加するという問題点も
発生する。従って、溝深さｈと管外径Ｄとの比ｈ／Ｄは
０．００８〜０．０１６とすることが必要である。な
お、溝深さと管外径との比ｈ／Ｄは０．０１０〜０．０
１４であることがより一層好ましい。 Ratio of groove depth h to outer diameter D of pipe h / D Heat transfer when the ratio of groove depth h of inner surface grooved heat transfer tube to outer diameter D of h / D is less than 0.008 The area is not sufficient, the disturbing effect of the refrigerant due to the mountain portion is reduced, and the heat transfer performance of the inner grooved heat transfer tube is reduced. On the other hand, the ratio of groove depth to pipe outer diameter h / D
Is more than 0.016, the metal flow in the axial direction of the pipe at the time of grooving becomes large and the metal flow in the radial direction of the pipe becomes small, making it difficult to form a deep groove. Further, in this case, since the machining load applied to each crest portion of the inner surface grooved heat transfer tube becomes large, cracks are likely to occur at the crest portion during groove processing on the inner surface grooved heat transfer tube, and the cracks are avoided. Manufacturing speed must be significantly reduced.
Further, there is a problem that the weight of the inner surface grooved heat transfer tube increases. Therefore, it is necessary to set the ratio h / D between the groove depth h and the pipe outer diameter D to 0.008 to 0.016. The ratio h / D between the groove depth and the pipe outer diameter is 0.010 to 0.0
Even more preferably, it is 14.

【００２３】山頂角α 山頂角αが４０°未満の場合は、内面溝付伝熱管の溝付
加工時の管軸方向へのメタルフローが大きくなると共
に、管の半径方向へのメタルフローが小さくなり、内面
溝付伝熱管に十分な深さの溝が得られない。また、内面
溝付伝熱管の各山部にかかる加工負荷が大きくなるた
め、溝付加工時に山部に亀裂が発生しやすくなり、内面
溝付伝熱管の製造速度が大幅に低下する。一方、山頂角
αが６０°を超える場合は、内面溝付伝熱管の溝付加工
時の管の半径方向へのメタルフローが大きくなり、加工
性は良好になるものの、内面溝付伝熱管の重量が増加す
ると共に、溝部の断面積が減少することにより溝部の冷
媒の厚膜化が生じ、伝熱性能が低下する。従って、山頂
角αは４０〜６０°とすることが必要である。なお、山
頂角αは、４５〜５５°とすることがより一層好まし
い。Crest angle α If the crest angle α is less than 40 °, the metal flow in the axial direction of the heat transfer tube with the inner surface groove becomes large and the metal flow in the radial direction of the tube becomes small. As a result, a groove with a sufficient depth cannot be obtained in the heat transfer tube with internal groove. Further, since the machining load applied to each crest portion of the inner grooved heat transfer tube becomes large, cracks are likely to occur in the crest portion during the grooved processing, and the manufacturing rate of the inner grooved heat transfer tube is significantly reduced. On the other hand, when the crest angle α exceeds 60 °, the metal flow in the radial direction of the grooved inner surface heat transfer tube becomes large and the workability is improved, but the inner surface grooved heat transfer tube As the weight increases and the cross-sectional area of the groove decreases, the refrigerant in the groove becomes thicker and the heat transfer performance deteriorates. Therefore, it is necessary to set the peak angle α to 40 to 60 °. The peak angle α is more preferably 45 to 55 °.

【００２４】管外面の管軸中心線平均粗さＲａ 内面溝付伝熱管を拡管して例えば、複数のフィンと密着
させて熱交換器を組立てる場合に、内面溝付伝熱管は塑
性変形して管軸方向に収縮し、内面溝付伝熱管の外面と
フィンとの間で滑りが発生する。この場合に、内面溝付
伝熱管外面の管軸方向においてＪＩＳ Ｂ０６０１に規
定される中心線平均粗さＲａが０．８μｍを超えると、
内面溝付伝熱管外面とフィンとの接触部の一部が密着
し、管外面とフィンとの間の滑りやすさにばらつきが生
じる。そして、内面溝付伝熱管外面に密着したフィン
は、内面溝付伝熱管の管軸方向への収縮に連動し、フィ
ンの相互間隔に疎密の不揃いが発生する。内面溝付伝熱
管外面の管軸方向の中心線平均粗さＲａが０．８μｍ以
下とすることにより、内面溝付伝熱管とフィンとの部分
的密着を回避でき、フィンの相互間隔の疎密の発生を回
避できる。従って、内面溝付伝熱管を拡管する際に、拡
管の速度を低減する必要がなくなり、熱交換器の生産性
が向上する。なお、外面の管軸方向の中心線平均粗さＲ
ａは、０．５μｍ以下とすることがより一層好ましい。 The tube axis center line average roughness Ra of the outer surface of the tube When the heat transfer tube with inner groove is expanded and, for example, a heat exchanger is assembled by closely contacting a plurality of fins, the heat transfer tube with inner groove is plastically deformed. It contracts in the tube axis direction, and slip occurs between the fin and the outer surface of the heat transfer tube with inner groove. In this case, when the center line average roughness Ra defined in JIS B0601 exceeds 0.8 μm in the tube axis direction of the inner grooved heat transfer tube outer surface,
A part of the contact portion between the outer surface of the heat transfer tube with inner groove and the fin is in close contact with each other, and the slipperiness between the outer surface of the tube and the fin varies. The fins that are in close contact with the outer surface of the inner grooved heat transfer tube are interlocked with the contraction of the inner grooved heat transfer tube in the axial direction of the tube, and unevenness in the spacing between the fins occurs. By setting the center line average roughness Ra of the outer surface of the inner grooved heat transfer tube in the tube axis direction to 0.8 μm or less, it is possible to avoid partial close contact between the inner grooved heat transfer tube and the fins, and to improve the spacing between the fins. Occurrence can be avoided. Therefore, when expanding the inner surface grooved heat transfer tube, it is not necessary to reduce the tube expansion speed, and the productivity of the heat exchanger is improved. The center line average roughness R of the outer surface in the pipe axis direction
It is even more preferable that a is 0.5 μm or less.

【００２５】[0025]

【実施例】以下、本発明の実施例について、その比較例
と比較して説明する。先ず、溝の断面積Ｓ₁ と山部の断
面積Ｓ₂ との比Ｓ₁ ／Ｓ₂ が相互に異なる内面溝付伝熱
管を製造し、外径が７ｍｍの供試管及び外径が９．５２
ｍｍの供試管を得た。材質はいずれもリン脱酸銅（ＪＩ
ＳＨ３３００，Ｃ１２２０）である。外径が７ｍｍの供
試管は、長さが３ｍ、底肉厚（溝部における肉厚）が
０．２５ｍｍである。また、外径が９．５２ｍｍの供試
管は、長さが４ｍ、底肉厚が０．２８ｍｍである。これ
らの伝熱管の溝深さｈと管外径Ｄとの比ｈ／Ｄは０．０
１２６、山頂角αは５０°、溝のねじれ角θは１５°で
ある。EXAMPLES Examples of the present invention will be described below in comparison with comparative examples. First, a heat transfer tube with an inner groove having different ratios S ₁ / S ₂ between the cross-sectional area S _{1 of the} groove and the cross-sectional area S ₂ of the crest portion was manufactured, and the test tube having the outer diameter of 7 mm and the outer diameter of 9. 52
mm test tubes were obtained. All materials are phosphorus deoxidized copper (JI
SH3300, C1220). The test tube having an outer diameter of 7 mm has a length of 3 m and a bottom wall thickness (wall thickness in the groove portion) of 0.25 mm. The test tube with an outer diameter of 9.52 mm has a length of 4 m and a bottom wall thickness of 0.28 mm. The ratio h / D between the groove depth h of these heat transfer tubes and the tube outer diameter D is 0.0
126, the crest angle α is 50 °, and the groove twist angle θ is 15 °.

【００２６】また、基準伝熱管として、外径が９．５２
ｍｍ、溝深さが０．１５ｍｍ、山頂角が９０°、管軸に
直交する断面における溝数が６５／周、ねじれ角が２５
°、底肉厚が０．２８ｍｍであり、溝形状が三角形状の
従来の伝熱管を用意した。The outer diameter of the standard heat transfer tube is 9.52.
mm, groove depth 0.15 mm, crest angle 90 °, number of grooves in cross section orthogonal to tube axis 65 / circle, twist angle 25
A conventional heat transfer tube having a triangular shape and a groove thickness of 0.28 mm was prepared.

【００２７】図３はこれらの伝熱管の伝熱性能を試験し
た試験装置を示す模式図である。供試管１９は二重管熱
交換器２０のハウジング内に挿入して配置するようにな
っている。この二重管熱交換器２０はその長手方向の一
方の側から水が供給され、この水がハウジングと供試管
１９との間を通り、他方の側から排出されるようになっ
ている。この二重管熱交換器２０の水入口側及び水出口
側には夫々温度計２１が設けられており、二重管熱交換
器２０に供給される水の温度及び二重管熱交換器２０か
ら排出される水の温度を測定できるようになっている。FIG. 3 is a schematic view showing a test device for testing the heat transfer performance of these heat transfer tubes. The test tube 19 is inserted and arranged in the housing of the double-tube heat exchanger 20. Water is supplied to the double-tube heat exchanger 20 from one side in the longitudinal direction, the water passes between the housing and the test tube 19, and is discharged from the other side. Thermometers 21 are provided on the water inlet side and the water outlet side of the double-tube heat exchanger 20, respectively. The temperature of the water supplied to the double-tube heat exchanger 20 and the double-tube heat exchanger 20. It is possible to measure the temperature of the water discharged from the.

【００２８】供試管１９の一方の端部は配管２２及び開
閉弁２８ｂ，２８ｃを介して熱交換器（蒸発器又は凝縮
器）２５の一端側に連結されている。また、開閉弁２８
ｂの供試管１９側と開閉弁２８ｃの熱交換器２５側との
間には開閉弁２８ａ，配管２７ａ，２７ｂ及び開閉弁２
８ｄからなる配管路が設けられており、更に開閉弁２８
ｂと開閉弁２８ｃとの連結部と、配管２７ａ，２７ｂの
連結部との間には、圧縮機２８及び配管２７ｃからなる
配管路が設けられている。One end of the test tube 19 is connected to one end of a heat exchanger (evaporator or condenser) 25 via a pipe 22 and opening / closing valves 28b and 28c. Also, the on-off valve 28
b between the sample tube 19 side of b and the heat exchanger 25 side of the on-off valve 28c, the on-off valve 28a, the pipes 27a and 27b, and the on-off valve 2
A pipe line consisting of 8d is provided, and the on-off valve 28
Between the connecting portion between b and the on-off valve 28c and the connecting portion between the pipes 27a and 27b, a pipe passage including the compressor 28 and the pipe 27c is provided.

【００２９】熱交換器２５の他端側はオーバル流量計２
６の一端側に連結されており、このオーバル流量計２６
の他端側と供試管１９との間には開閉弁２８ｆが設けら
れた配管２２ｂ及び開閉弁２８ｅが設けられた配管２２
ａが並列に連結されている。The other end of the heat exchanger 25 has an oval flowmeter 2
6 is connected to one end side of the oval flow meter 26
A pipe 22b provided with an on-off valve 28f and a pipe 22 provided with an on-off valve 28e between the other end of the pipe and the test pipe 19.
a is connected in parallel.

【００３０】供試管１９の両側にはいずれも温度計２１
及び圧力計２３が設けられており、供試管１９に入る凝
固媒体又は蒸発媒体及び供試管１９から出た凝固媒体又
は蒸発媒体の温度及び動歪圧力Ｐを測定できるようにな
っている。また、動歪差圧計２４により、２つの圧力計
２３の差圧を検出できるようになっている。A thermometer 21 is provided on each side of the test tube 19.
Also, a pressure gauge 23 is provided so that the temperature and dynamic strain pressure P of the solidification medium or the evaporation medium entering the sample tube 19 and the solidification medium or the evaporation medium discharged from the sample tube 19 can be measured. Further, the dynamic strain differential pressure gauge 24 can detect the differential pressure between the two pressure gauges 23.

【００３１】このように構成された試験装置を使用し、
供試管１９と試験部２０のハウジングとの間に水を冷媒
に対して向流となる方向に流して、供試管の伝熱性能を
調べた。試験条件を下記表１に示す。但し、蒸発試験に
おいては、冷媒が完全に蒸発した後、供試管の出口にお
いて所定の過熱度となるように水温を調整した。また、
凝縮試験においても、冷媒が完全に凝縮した後、供試管
１９の出口において所定の過冷却度となるように水温を
調整した。そして、蒸発及び凝縮試験のいずれにおいて
も、安定の確認後、冷媒の温度、流量及び圧力並びに水
の温度及び流量を測定し、伝熱性能を算出した。Using the test apparatus configured as described above,
Water was passed between the test tube 19 and the housing of the test section 20 in a direction countercurrent to the refrigerant, and the heat transfer performance of the test tube was examined. The test conditions are shown in Table 1 below. However, in the evaporation test, the water temperature was adjusted so that a predetermined superheat degree was obtained at the outlet of the test tube after the refrigerant was completely evaporated. Also,
Also in the condensation test, the water temperature was adjusted so that a predetermined degree of supercooling was obtained at the outlet of the test tube 19 after the refrigerant was completely condensed. Then, in both the evaporation and condensation tests, after confirming the stability, the temperature, flow rate and pressure of the refrigerant and the temperature and flow rate of water were measured to calculate the heat transfer performance.

【００３２】[0032]

【表１】 [Table 1]

【００３３】但し、表１において蒸発温度は蒸発器出口
における圧力に相当する飽和温度である。また、凝縮温
度は凝縮器入口における圧力に相当する飽和温度であ
る。更に、熱負荷とは、伝熱量（kcal/h）／供試管外表
面積（m²）として表される。更にまた、製造速度は転造
加工部の回転数２００００r.p.m で転造加工を施し、所
定の溝形状が得られる上限の速度である。However, in Table 1, the evaporation temperature is a saturation temperature corresponding to the pressure at the evaporator outlet. The condensation temperature is the saturation temperature corresponding to the pressure at the condenser inlet. Further, the heat load is expressed as heat transfer amount (kcal / h) / external surface area of test tube (m ² ). Furthermore, the manufacturing speed is an upper limit speed at which a predetermined groove shape can be obtained by performing the rolling process at the number of revolutions of the rolling process section of 20000 rpm.

【００３４】次に、この伝熱性能試験の結果について説
明する。図４は、横軸に内面溝付伝熱管の溝の断面積Ｓ
₁ と山部の断面積Ｓ₂ との比Ｓ₁ ／Ｓ₂ をとり、縦軸に
基準伝熱管に対する伝熱性能比（蒸発性能比、凝縮性能
比）、製造速度比及び重量比をとって、Ｓ₁ ／Ｓ₂ とこ
れら特性との関係を示すグラフ図である。Next, the results of this heat transfer performance test will be described. FIG. 4 shows the cross-sectional area S of the groove of the heat transfer tube with the inner groove on the horizontal axis.
Takes a ₁ and a ratio S ₁ / S ₂ of the cross-sectional area S ₂ of the crest, the heat transfer performance ratio with respect to the reference heat transfer tube in the longitudinal axis (evaporation performance ratio, the condensation performance ratio), taking manufacturing speed ratio and weight ratio , S ₁ / S ₂ and graphs showing the relationship between these characteristics.

【００３５】図４から明らかなように、Ｓ₁ ／Ｓ₂ が
２．５未満であると、溝の面積が小さく、溝間における
冷媒の液膜の厚さが厚くなるため、伝熱抵抗が増加し、
伝熱性能が低下した。また、Ｓ₁ ／Ｓ₂ が４．５を超え
ると、溝間隔が広すぎるため、伝熱面積が減少し、伝熱
性能が低下した。更に、内面溝付伝熱管の製造時に管軸
に直交する方向に比較して管軸方向へのメタルフローが
大きくなるため、所定の形状の溝を形成しにくくなると
共に、山部の強度が低下して溝付加工時に山部に亀裂が
生じた。その結果、不良品が発生しやすくなり、製造速
度が低下した。As is clear from FIG. 4, when S ₁ / S ₂ is less than 2.5, the area of the groove is small, and the thickness of the liquid film of the refrigerant between the grooves is large. Increased,
The heat transfer performance has deteriorated. On the other hand, when S ₁ / S ₂ exceeds 4.5, the groove interval is too wide, so that the heat transfer area is reduced and the heat transfer performance is deteriorated. Furthermore, when manufacturing the heat transfer tube with inner groove, the metal flow in the tube axis direction becomes larger than that in the direction orthogonal to the tube axis, which makes it difficult to form grooves of a predetermined shape and reduces the strength of the crests. As a result, cracks occurred in the ridges during the grooving process. As a result, defective products were more likely to occur, and the manufacturing speed decreased.

【００３６】従って、Ｓ₁ ／Ｓ₂ が２．５〜４．５であ
れば冷媒を適度な厚さに維持することができ、溝の面積
もそれほど減少しないため、伝熱性能の低下が生じな
い。また、転造加工時において、管軸方向へのメタルフ
ローがそれほど大きくならず、良好な溝形状を得ること
ができる。なお、Ｓ₁ ／Ｓ₂ が３．０〜４．０であれ
ば、更に一層伝熱性能の低下を防止でき、製造速度も良
好であると共に重量も小さい。Therefore, when S ₁ / S ₂ is 2.5 to 4.5, the refrigerant can be maintained at an appropriate thickness and the groove area does not decrease so much, so that the heat transfer performance is deteriorated. Absent. Further, during the rolling process, the metal flow in the pipe axis direction does not become so large, and a good groove shape can be obtained. If S ₁ / S ₂ is 3.0 to 4.0, the heat transfer performance can be prevented from being further reduced, the production rate is good, and the weight is small.

【００３７】図５は、横軸に内面溝付伝熱管の溝深さｈ
と管外径Ｄとの比ｈ／Ｄをとり、縦軸に基準伝熱管との
伝熱性能比（蒸発性能比、凝縮性能比）、製造速度比及
び重量比をとって、ｈ／Ｄとこれらの特性との関係を示
すグラフ図である。なお、各供試管の溝の断面積と山部
の断面積との比Ｓ₁ ／Ｓ₂ は３〜４、山頂角αは５０
°、溝のねじれ角θは１５°とした。また、基準伝熱管
は、前述の基準伝熱管と同一のものである。FIG. 5 shows the groove depth h of the heat transfer tube with inner groove on the horizontal axis.
And the outer diameter D of the pipe, the ratio h / D is taken, and the vertical axis shows the heat transfer performance ratio (evaporation performance ratio, condensation performance ratio) with the reference heat transfer tube, the production speed ratio and the weight ratio, and the result is h / D. It is a graph which shows the relationship with these characteristics. The ratio S ₁ / S ₂ of the cross-sectional area of the groove and the cross-sectional area of the crest of each test tube is 3 to 4, and the crest angle α is 50.
The groove twist angle θ was 15 °. The reference heat transfer tube is the same as the reference heat transfer tube described above.

【００３８】図５から明らかなように、内面溝付伝熱管
のｈ／Ｄが０．００８未満では溝の断面積が減少し、伝
熱性能が低下した。また、ｈ／Ｄが大きいほど伝熱性能
は向上するが、内面溝付伝熱管の転造加工時の転造部の
押圧力を大きくする必要がある。ｈ／Ｄが０．０１６を
超えると、潤滑油切れによる山部の亀裂を回避するため
に、製造速度を低減する必要があり、生産性が著しく低
下すると共に、内面溝付伝熱管の重量も増加した。As is apparent from FIG. 5, when h / D of the heat transfer tube with inner groove was less than 0.008, the cross-sectional area of the groove was reduced and the heat transfer performance was deteriorated. Further, the larger h / D is, the more the heat transfer performance is improved, but it is necessary to increase the pressing force of the rolling portion during the rolling process of the inner surface grooved heat transfer tube. If h / D exceeds 0.016, it is necessary to reduce the production speed in order to avoid cracks in the ridges due to running out of lubricating oil, which significantly reduces productivity and also the weight of the heat transfer tube with inner groove. Increased.

【００３９】従って、内面溝付伝熱管の溝深さｈと管外
径Ｄとの比ｈ／Ｄが０．００８〜０．０１６であれば、
製造速度及び伝熱性能の低下は殆ど生じない。ｈ／Ｄが
０．０１０〜０．０１４であれば、製造速度及び伝熱性
能が良好であると共に、重量もそれ程増加しない。Therefore, if the ratio h / D of the groove depth h of the inner surface grooved heat transfer tube to the tube outer diameter D is 0.008 to 0.016,
The production speed and the heat transfer performance are hardly deteriorated. When h / D is 0.010 to 0.014, the production rate and heat transfer performance are good, and the weight does not increase so much.

【００４０】図６は、横軸に内面溝付伝熱管の山部の山
頂角αをとり、縦軸に基準伝熱管との伝熱性能比（蒸発
性能比、凝縮性能比）、製造速度比及び重量比をとっ
て、山頂角αとこれらの特性との関係を示すグラフ図で
ある。なお、各供試管の溝深さｈと管外径Ｄとの比ｈ／
Ｄは０．０１２６、溝の断面積と山部の断面積との比Ｓ
₁ ／Ｓ₂ は３〜４、溝のねじれ角θは１５°とした。ま
た、基準伝熱管は、前述した基準伝熱管と同一のもので
ある。In FIG. 6, the horizontal axis shows the crest angle α of the crest portion of the heat transfer tube with internal groove, and the vertical axis shows the heat transfer performance ratio (evaporation performance ratio, condensation performance ratio) with the reference heat transfer tube, and the production speed ratio. FIG. 4 is a graph showing the relationship between the peak angle α and these characteristics by taking the weight ratios and. The ratio of the groove depth h of each test tube to the tube outer diameter D h /
D is 0.0126, the ratio S of the sectional area of the groove to the sectional area of the mountain portion.
₁ / S ₂ was 3 to 4, and the twist angle θ of the groove was 15 °. The reference heat transfer tube is the same as the reference heat transfer tube described above.

【００４１】図６から明らかなように、内面溝付伝熱管
の山頂角αが４０°未満では山部の強度が低下し、転造
加工時に山部に亀裂が生じやすく、その結果、製造速度
も低下した。また、山頂角αが６０°を超えると、溝の
間隔が小さくなり、冷媒の液膜の厚さが増加して伝熱性
能が低下すると共に、内面溝付伝熱管の重量が増加し
た。As is apparent from FIG. 6, when the crest angle α of the inner grooved heat transfer tube is less than 40 °, the strength of the crest portion is lowered and cracks are likely to occur in the crest portion during the rolling process. Also fell. Further, when the crest angle α exceeds 60 °, the gap between the grooves becomes small, the thickness of the liquid film of the refrigerant increases, the heat transfer performance deteriorates, and the weight of the inner surface grooved heat transfer tube increases.

【００４２】従って、内面溝付伝熱管の山頂角αが４０
〜６０°であれば、冷媒の厚膜化が生じないため、伝熱
性能は低下しない。また、山部の強度が低下せず、溝付
加工時に山部に亀裂が生じにくいため、製造速度も低下
しないと共に、重量もそれ程増加しない。なお、山頂角
αが４５〜５５°であれば、製造速度及び伝熱性能がい
ずれも良好であり、内面溝付伝熱管の重量も増加しな
い。Therefore, the peak angle α of the heat transfer tube with the inner groove is 40.
If it is -60 °, the heat transfer performance does not decrease because the thickening of the refrigerant does not occur. In addition, the strength of the crests does not decrease, and cracks are less likely to occur in the crests during grooving, so the manufacturing speed does not decrease and the weight does not increase so much. When the peak angle α is 45 to 55 °, both the production speed and the heat transfer performance are good, and the weight of the heat transfer tube with the inner groove does not increase.

【００４３】なお、本実施例においては、ねじれ角θが
１５°の場合について説明したが、本発明においては、
ねじれ角θは特に限定するものではない。しかし、伝熱
性能、圧力損失及び加工性を考慮すると、ねじれ角θは
８〜１８°であることが好ましく、１３〜１７°であれ
ばより一層好ましい。In this embodiment, the case where the twist angle θ is 15 ° has been described, but in the present invention,
The twist angle θ is not particularly limited. However, in consideration of heat transfer performance, pressure loss and workability, the twist angle θ is preferably 8 to 18 °, and more preferably 13 to 17 °.

【００４４】次に、内面溝付伝熱管の外面の管軸方向の
中心線平均粗さＲａの影響について調べた結果について
説明する。供試管に対し転造加工を施した。この場合
に、内面溝付伝熱管の外周面の粗さを変化させるため
に、転造部の径を変化させて転造加工後の管外径を変化
させた。これにより、仕上げダイスによる外径落とし率
が０〜約１５％の範囲内で変化し、管軸方向の中心線平
均粗さが夫々０．４μｍ及び０．７μｍの実施例１，２
の内面溝付伝熱管及び中心線平均粗さが０．９μｍ、
１．２μｍ及び１．５μｍの比較例３，４，５の内面溝
付伝熱管を得た。なお、内面溝付伝熱管の管外面の中心
線平均粗さは、ＪＩＳ Ｂ０６０１に準拠して、カット
オフ値が２．５ｍｍ、測定長さが１０ｍｍの条件で測定
した。また、内面溝付伝熱管内の溝形状は、溝深さが
０．１５ｍｍ、ねじれ角が１５°、溝数が６５個／周、
山頂角が５０°とした。Next, the results of examining the influence of the centerline average roughness Ra in the tube axis direction of the outer surface of the inner surface grooved heat transfer tube will be described. The test tube was rolled. In this case, in order to change the roughness of the outer peripheral surface of the inner surface grooved heat transfer tube, the diameter of the rolling portion was changed to change the outer diameter of the tube after the rolling process. Thereby, the outer diameter reduction rate by the finishing die changes within the range of 0 to about 15%, and the center line average roughness in the tube axis direction is 0.4 μm and 0.7 μm, respectively.
Inner groove heat transfer tube and center line average roughness 0.9 μm,
The heat transfer tubes with inner grooves of Comparative Examples 3, 4 and 5 having 1.2 μm and 1.5 μm were obtained. The centerline average roughness of the outer surface of the heat transfer tube with inner groove was measured under the conditions of a cutoff value of 2.5 mm and a measurement length of 10 mm in accordance with JIS B0601. In addition, the groove shape in the heat transfer tube with inner groove has a groove depth of 0.15 mm, a helix angle of 15 °, and the number of grooves is 65 / perimeter,
The summit angle was 50 °.

【００４５】次に、実施例１，２及び比較例３，４，５
の内面溝付伝熱管を多数平行に配置したアルミニウムフ
ィンの開口部へ挿入し、内面溝付伝熱管を拡管速度が１
０ｍ／分、外径基準の拡管率が１０４，１０５，１０６
％で拡管した。この場合に、アルミニウムフィンの相互
間隔に疎密が発生するか否かを調べた。その結果を、下
記表２に示す。Next, Examples 1, 2 and Comparative Examples 3, 4, 5
Insert a large number of inner grooved heat transfer tubes into the openings of aluminum fins that are arranged in parallel, and expand the inner grooved heat transfer tubes at a pipe expansion speed of 1
0m / min, the expansion ratio of outer diameter is 104, 105, 106
Expanded by%. In this case, it was investigated whether or not the spacing between the aluminum fins was uneven. The results are shown in Table 2 below.

【００４６】[0046]

【表２】 [Table 2]

【００４７】なお、表２においてアルミニウムフィンに
疎密発生欄の評価基準は、内面溝付伝熱管の拡管時にア
ルミニウムフィンの相互間隔に疎密が発生した場合を
×、発生しない場合を○、疎密が発生したものの頻度が
少ない場合を△とした。In Table 2, the evaluation criteria in the column where the aluminum fins are sparse and dense are evaluated as follows: when the inner fins are spaced apart from each other during the expansion of the heat transfer tube with internal grooves, x indicates the sparse and dense intervals, and when not, the ◯ indicates sparse and dense occurrence. However, when the frequency was low, it was evaluated as Δ.

【００４８】表２から明らかなように、内面溝付伝熱管
外面の中心線平均粗さが０．８μｍを超える比較例３〜
５においては、拡管率が１０５％でアルミニウムフィン
の相互間隔に疎密が発生した。内面溝付伝熱管外面の中
心線平均粗さが０．８μｍ以下である実施例１，２にお
いては、伝熱管の拡管時に拡管率が１０５％であっても
アルミニウムフィンの相互間隔に疎密は発生しなかっ
た。また、実施例１，２においては、内面溝付伝熱管外
面の中心線平均粗さが０．５μｍ以下であれば、拡管率
が１０６％であってもアルミニウムフィンの相互間隔に
疎密は発生せず、良好に拡管することができた。As is clear from Table 2, Comparative Example 3 in which the center line average roughness of the outer surface of the heat transfer tube with inner groove exceeds 0.8 μm
In No. 5, the expansion ratio was 105%, and sparseness and denseness occurred in the mutual intervals of the aluminum fins. In Examples 1 and 2 in which the center line average roughness of the outer surface of the heat transfer tube with the inner groove is 0.8 μm or less, sparseness and denseness occur in the mutual spacing of the aluminum fins even when the expansion rate is 105% when expanding the heat transfer tube. I didn't. Further, in Examples 1 and 2, if the center line average roughness of the outer surface of the heat transfer tube with inner groove was 0.5 μm or less, the spacing between the aluminum fins did not become uneven even if the expansion ratio was 106%. The tube was successfully expanded.

【００４９】[0049]

【発明の効果】以上説明したように、本発明によれば、
管内面に連続する螺旋状の溝を有する管外径Ｄの内面溝
付伝熱管において、管軸に直交する断面における溝の断
面積Ｓ₁ と前記溝の間の山部の断面積Ｓ₂ との比Ｓ₁ ／
Ｓ₂ を２．５〜４．５、溝深さｈと管外径Ｄとの比ｈ／
Ｄを０．００８〜０．０１６、前記山部の両斜面のなす
山頂角αを４０〜６０°、管外面の管軸方向の中心線平
均粗さＲａを０．８μｍ以下に設定したから、伝熱性能
が高く、軽量であると共に生産性が高く、更に熱交換器
の組立時にも生産性が高い内面溝付伝熱管を得ることが
できる。As described above, according to the present invention,
In a heat transfer tube with an inner groove having an outer diameter D having a spiral groove continuous to the inner surface of the tube, a cross-sectional area S ₁ of the groove in a cross section orthogonal to the tube axis and a cross-sectional area S ₂ of a mountain portion between the grooves. Ratio of S ₁ /
S ₂ is 2.5 to 4.5, the ratio of groove depth h to pipe outer diameter D is h /
Since D is set to 0.008 to 0.016, the crest angle α formed by both slopes of the mountain portion is set to 40 to 60 °, and the center line average roughness Ra in the pipe axis direction of the pipe outer surface is set to 0.8 μm or less, It is possible to obtain a heat transfer tube with an inner groove, which has high heat transfer performance, is lightweight, has high productivity, and has high productivity even when assembling a heat exchanger.

【図面の簡単な説明】[Brief description of drawings]

【図１】本発明の内面溝付伝熱管の形状、溝の形成過程
及び溝方向を説明する管の一部破断平面図である。FIG. 1 is a partially cutaway plan view of a tube for explaining the shape of a heat transfer tube with an inner groove, the groove forming process, and the groove direction of the present invention.

【図２】本発明の溝形状を説明するための管軸に直角方
向の断面図である。FIG. 2 is a cross-sectional view in a direction perpendicular to the tube axis for explaining the groove shape of the present invention.

【図３】実施例で使用した試験装置の概要を示す模式図
である。FIG. 3 is a schematic diagram showing an outline of a test apparatus used in Examples.

【図４】Ｓ₁ ／Ｓ₂ と伝熱性能比（蒸発性能比、凝縮性
能比）、製造速度比及び重量比との関係を示すグラフ図
である。FIG. 4 is a graph showing a relationship between S ₁ / S ₂ and a heat transfer performance ratio (evaporation performance ratio, condensation performance ratio), a production speed ratio, and a weight ratio.

【図５】ｈ／Ｄと伝熱性能比（蒸発性能比、凝縮性能
比）、製造速度比及び重量比との関係を示すグラフ図で
ある。FIG. 5 is a graph showing a relationship between h / D and a heat transfer performance ratio (evaporation performance ratio, condensation performance ratio), a production speed ratio, and a weight ratio.

【図６】山頂角αと伝熱性能比（蒸発性能比、凝縮性能
比）、製造速度比及び重量比との関係を示すグラフ図で
ある。FIG. 6 is a graph showing a relationship between a peak angle α and a heat transfer performance ratio (evaporation performance ratio, condensation performance ratio), a production speed ratio, and a weight ratio.

【図７】内面溝付伝熱管の転造加工方法を示す模式図で
ある。FIG. 7 is a schematic view showing a rolling method of the heat transfer tube with the inner groove.

【図８】内面溝付伝熱管とフィンとの組立方法を示す模
式図である。FIG. 8 is a schematic diagram showing a method of assembling the heat transfer tube with internal grooves and the fins.

【図９】同じくその方法におけるフィンの相互間隔の疎
密の発生を示す模式図である。FIG. 9 is a schematic diagram showing occurrence of sparseness and denseness of mutual spacing of fins in the same method.

【符号の説明】[Explanation of symbols]

Ｓ₁ ；溝の断面積 Ｓ₂ ；山部の断面積 ｈ；溝深さ Ｄ；管外径 Ｒａ；中心線平均粗さ θ；ねじれ角 １；凸部 ２；凹部 ３；溝 ４；管外面 ５；頂点 ６；溝底面 ７；延長線 ８ａ，８ｂ；斜面 １０；山部 １２；被加工管 １３；球 １４ａ；引抜きダイス １４ｂ；仕上げダイス １５，１９；内面溝付伝熱管 １６；アルミニウムフィン １６ａ；開孔部 １７；拡管用工具 １８；疎密部S ₁ ; cross-sectional area of groove S ₂ ; cross-sectional area of crest h; groove depth D; pipe outer diameter Ra; center line average roughness θ; helix angle 1; convex portion 2; concave portion 3; groove 4; pipe outer surface 5; Vertex 6; Groove bottom surface 7; Extension lines 8a, 8b; Slope surface 10; Crest portion 12; Pipe to be processed 13; Sphere 14a; Drawing die 14b; Finishing die 15, 19; Heat transfer tube with inner surface groove 16; Aluminum fin 16a Opening part 17; Expansion tool 18; Dense part

───────────────────────────────────────────────────── フロントページの続き (72)発明者 石川 守 神奈川県秦野市平沢65番地 株式会社神戸 製鋼所秦野工場内 (72)発明者 内田 哲夫 神奈川県秦野市平沢65番地 株式会社神戸 製鋼所秦野工場内 (72)発明者 肥後 富夫 神奈川県秦野市平沢65番地 株式会社神戸 製鋼所秦野工場内 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Mamoru Ishikawa 65 Hirazawa, Hadano City, Kanagawa Prefecture Kobe Steel Works, Ltd., Hadano Plant (72) Tetsuo Uchida 65 Hirazawa, Hadano City, Kanagawa Prefecture Kobe Steel Works, Ltd. Hadano Plant, Ltd. (72) Inventor Tomio Higo 65 Hirazawa, Hadano City, Kanagawa Prefecture Kobe Steel Works, Ltd., Hadano Plant

Claims (5)

【特許請求の範囲】[Claims] 【請求項１】 管内面に連続する螺旋状の溝を有する管
外径Ｄの内面溝付伝熱管において、管軸に直交する断面
における溝の断面積Ｓ₁ と前記溝の間の山部の断面積Ｓ
₂ との比Ｓ₁ ／Ｓ₂ が２．５≦Ｓ₁ ／Ｓ₂ ≦４．５、前
記溝の深さｈと前記管外径Ｄとの比ｈ／Ｄが０．００８
≦ｈ／Ｄ≦０．０１６、前記山部の両斜面のなす山頂角
αが４０°≦α≦６０°の範囲にあり、管外面の管軸方
向の中心線平均粗さＲａがＲａ≦０．８μｍであること
を特徴とする内面溝付伝熱管。1. A heat transfer tube with an inner surface groove having a pipe outer diameter D having a continuous spiral groove on the inner surface of the tube, wherein a cross sectional area S ₁ of the groove in a cross section orthogonal to the pipe axis and a mountain portion between the grooves. Cross-sectional area S
₂ ratio of S ₁ / S ₂ is _{2.5 ≦ S 1 / S 2 ≦} 4.5, the ratio h / D of the tube outside diameter D and the depth h of the groove 0.008
≦ h / D ≦ 0.016, the crest angle α formed by both slopes of the mountain portion is in the range of 40 ° ≦ α ≦ 60 °, and the centerline average roughness Ra of the pipe outer surface in the pipe axis direction is Ra ≦ 0. An inner grooved heat transfer tube characterized by having a diameter of 0.8 μm. 【請求項２】 前記比Ｓ₁ ／Ｓ₂ が３．０≦Ｓ₁ ／Ｓ₂
≦４．０であることを特徴とする請求項１に記載の内面
溝付伝熱管。2. The ratio S ₁ / S ₂ is 3.0 ≦ S ₁ / S ₂
The heat transfer tube with an inner groove according to claim 1, wherein ≦ 4.0. 【請求項３】 前記比ｈ／Ｄが０．０１０≦ｈ／Ｄ≦
０．０１４であることを特徴とする請求項１又は２に記
載の内面溝付伝熱管。3. The ratio h / D is 0.010 ≦ h / D ≦.
It is 0.014, The heat transfer tube with an inner surface groove | channel of Claim 1 or 2 characterized by the above-mentioned. 【請求項４】 前記山頂角αが４５°≦α≦５５°であ
ることを特徴とする請求項１乃至３のいずれか１項に記
載の内面溝付伝熱管。4. The heat transfer tube with internal groove according to claim 1, wherein the peak angle α is 45 ° ≦ α ≦ 55 °. 【請求項５】 前記中心線平均粗さＲａがＲａ≦０．５
μｍであることを特徴とする請求項１乃至４のいずれか
１項に記載の内面溝付伝熱管。5. The center line average roughness Ra is Ra ≦ 0.5.
The heat transfer tube with an inner groove according to claim 1, wherein the heat transfer tube has an inner groove.