Unequal-thickness tubular vapor chamber with bosses

Abstract

The utility model discloses an unequal thickness tubular vapor chamber with bosses, which comprises a cavity tube body formed by connecting two sides of a sheet body, the cavity tube body comprises an upper tube body and a lower tube body, the inner side of the upper tube body is provided with a plurality of first bosses, the plurality of first bosses are formed by rolling the upper tube body at one time, and the lower tube body is provided with a plurality of second bosses. A plurality of first bosses are arranged on the inner side of the upper pipe body, a plurality of second bosses corresponding to the first bosses are arranged on the inner side of the lower pipe body, the second bosses are formed by rolling the lower pipe body at a time, the two ends of the upper pipe body are obliquely bent inwards to form first bent parts, the two ends of the lower pipe body are bent inwards to form second bent parts, and the first bent parts and the second bent parts are connected in a sealed mode. According to the vapor chamber, the first boss and the second boss are arranged, so that the thicknesses of the pipe bodies are inconsistent, the first boss and the second boss are connected, the overall thickness is increased, the overall strength of the pipe bodies is improved, the part, not provided with the first boss and the second boss, of the pipe bodies can be made thin, and therefore the heat dissipation performance of the vapor chamber is greatly improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of uniform temperature plate preparation, especially to an unequal-thickness tubular uniform temperature plate with bosses. BACKGROUND

[0002] With the continuous increase of electronic chip heat flux density and the increase of power demand, the traditional air cooling technology has been unable to meet the heat dissipation demand of highly integrated electronic chips, and liquid cooling technology has gradually become the market mainstream. The current liquid cooling technology includes direct cooling and indirect cooling. Direct cooling is to fill the case with insulating liquid such as fluorinated liquid to directly contact and dissipate heat with electronic chips. This way is limited by insulating liquid, has high cost and is not easy to maintain, and is less used in the market. Indirect cooling is to provide a liquid flow channel in the liquid cooling plate, and the fluid is brought away by the contact of the liquid cooling plate and the electronic chip. Since the fluid is not in direct contact with the electronic chip, indirect cooling is more popular in existing liquid cooling technology. However, the process of opening a liquid flow channel in the liquid cooling plate is relatively complex, the cost is high, and the liquid cooling plate with a liquid flow channel is prone to deformation under pressure during installation and use due to low strength, which seriously affects the overall heat dissipation performance. In order to solve this problem, the prior art improves the thickness of the liquid cooling plate to improve the installation strength. However, the liquid cooling plate with excessive thickness cannot guarantee the heat dissipation efficiency, resulting in low heat dissipation efficiency, and the excessive size does not meet the market development demand. SUMMARY

[0003] The utility model discloses to the above-mentioned problem, provide a kind of unequal-thickness tubular uniform temperature plate with boss, the inner side of upper pipe body is provided with multiple first boss, the inner side of lower pipe body is provided with multiple second boss, so that the thickness of pipe body is inconsistent, first boss and second boss connect to improve overall thickness, improve the strength of pipe body as a whole, the part that is not provided with first boss and second boss can be thin, so that the heat dissipation performance of uniform temperature plate is greatly improved.

[0004] To achieve the above-mentioned utility model purposes, the technical scheme adopted by the utility model is as follows:

[0005] According to one aspect of the present application, an unequal-thickness tubular uniform temperature plate with bosses is provided, comprising a cavity pipe body formed by connecting one piece body through two sides, the cavity pipe body comprising an upper pipe body and a lower pipe body;

[0006] The inner side of the upper pipe body is provided with multiple first bosses, and the multiple first bosses are formed by rolling the upper pipe body once. The inner side of the lower pipe body is provided with multiple second bosses corresponding to the first bosses, and the multiple second bosses are formed by rolling the lower pipe body once. The first bosses are fixedly connected with the corresponding second bosses.

[0007] The two ends of the upper tube body are respectively inwardly inclined and curved to form first bending portions, and the two ends of the lower tube body are respectively inwardly curved to form second bending portions, and the first bending portions are sealingly connected with the second bending portions.

[0008] Preferably, the radial dimension of the first and second bosses gradually decreases from the bottom to the top, and the end surface of the top of the first and second bosses is horizontally arranged.

[0009] Preferably, the end surface of the top of the first boss is connected with the end surface of the top of the second boss.

[0010] Preferably, the liquid absorption core is fixedly arranged on the inner side wall of the upper tube body, the outer side wall of the first boss, and the outer side wall of the second boss.

[0011] Preferably, the outer side wall of the upper tube body is provided with a heat dissipation fin, and the heat dissipation fin is fixedly connected with the upper tube body.

[0012] Preferably, the heat dissipation fin comprises a first fold line type fin group and a second fold line type fin group, and the first fold line type fin group and the second fold line type fin group are alternately arranged along the transverse direction of the upper tube body.

[0013] The first fold line type fin group comprises a plurality of first fold line type fins arranged in sequence along the longitudinal direction of the upper tube body, and the plurality of first fold line type fins are connected in sequence.

[0014] The second fold line type fin group comprises a plurality of second fold line type fins arranged in sequence along the longitudinal direction of the upper tube body, and the plurality of second fold line type fins are connected in sequence.

[0015] The wave crest of the first fold line type fin is arranged in a staggered manner with the wave crest of the second fold line type fin.

[0016] Preferably, the heat dissipation fin comprises a third fold line type fin group, the third fold line type fin group comprises a plurality of third fold line type fins arranged in sequence along the longitudinal direction of the upper tube body, and the plurality of third fold line type fins are connected in sequence, and the wave crest of the third fold line type fin is arranged in a wave shape along the transverse direction of the upper tube body.

[0017] Preferably, the heat dissipation fin comprises a fourth fold line type fin group, the fourth fold line type fin group comprises a plurality of fourth fold line type fins arranged in sequence along the transverse direction of the upper tube body, and the plurality of fourth fold line type fins are connected in sequence, and the wave crest of the fourth fold line type fin is arranged in a straight line shape along the longitudinal direction of the upper tube body.

[0018] Preferably, a preparation process of a non-uniform thickness tube type uniform heat plate with bosses comprises the following steps:

[0019] S1, selecting a plane substrate, rolling along the longitudinal direction of the plane substrate to form a first group of bosses and a second group of bosses on one side of the plane substrate, the first group of bosses and the second group of bosses are arranged in axial symmetry, wherein the first group of bosses comprises at least one first boss column composed of a plurality of first bosses arranged along the longitudinal direction of the plane substrate, and the second group of bosses comprises at least one second boss column composed of a plurality of second bosses arranged along the longitudinal direction of the plane substrate;

[0020] S2, rolling the two sides of the plane substrate after rolling to form a connecting part with an arc, the connecting part is curved to the side with the boss, and then rolling the middle part of the plane substrate to make the two connecting parts of the plane substrate close to each other to form a U-shaped material, and continue to roll until the two connecting parts are in contact, and the two connecting parts are welded to form an O-shaped pipe body;

[0021] S3, rolling the two opposite sides of the O-shaped pipe body until the corresponding first boss and the second boss are in contact, and the O-shaped pipe body becomes an elliptical pipe body, and the elliptical pipe body is cut to form a pipe body segment, the pipe body segment is cleaned and leak tested;

[0022] S4, welding the contact part of the first boss and the second boss in the pipe body segment, and stamping one end of the pipe body segment to make the upper and lower sides of the end part in close contact, and welding the contact part to form a semi-sealed pipe body segment, and passing a liquid into the open end of the semi-sealed pipe body segment for water test detection, and after water test detection, vacuumizing the semi-sealed pipe body segment from the open end and injecting cooling liquid;

[0023] S5, stamping and welding the open end of the semi-sealed pipe body segment to seal both ends of the pipe body segment to form a uniform temperature plate.

[0024] Preferably, in the step S5, the following steps are further included:

[0025] Selecting a heat dissipation fin, and tightly attaching the heat dissipation fin to an outer side wall of the uniform temperature plate;

[0026] Welding at the contact part of the heat dissipation fin and the uniform temperature plate to fix the heat dissipation fin on the outer side wall of the uniform temperature plate.

[0027] As described above, due to the adoption of the above technical scheme, the beneficial effects of the present application are:

[0028] The utility model discloses a temperature equalizing plate is formed by the cavity pipe body of one piece body through two sides connection, and then the both ends of cavity pipe body are sealed to form temperature equalizing plate, and the cavity pipe body includes upper pipe body and lower pipe body, and the inside of upper pipe body is provided with a plurality of first boss, and the inside of lower pipe body is provided with a plurality of second boss, to make the thickness of pipe body inconsistent, and the overall thickness is improved by the connection of first boss and second boss, and the overall strength of pipe body is improved, and the part without first boss and second boss can be thin, to greatly improve the heat dissipation performance of temperature equalizing plate. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is the three-dimensional structure schematic diagram of the utility model;

[0030] Figure 2 It is the internal structure section view of the utility model;

[0031] Figure 3 It is the rolling rolling equipment structure schematic diagram of the utility model;

[0032] Figure 4 It is the heat dissipation fin structure schematic diagram of embodiment 1 of the utility model;

[0033] Figures 5-8 It is the simulation nephogram of comparative example 1-3 and example 1 in the comparative experiment of the utility model.

[0034] Figure 9 It is the heat dissipation fin structure schematic diagram of embodiment 2 of the utility model;

[0035] Figure 10 It is the heat dissipation fin structure schematic diagram of embodiment 3 of the utility model;

[0036] Figures 11-15 It is the simulation nephogram of comparative example 1-3 and example 1 in the comparative experiment of the utility model.

[0037] In the drawings, 1, upper pipe body;2, lower pipe body;3, first boss;4, second boss;5, first bending part;6, second bending part;7, heat dissipation fin;8, first bending type fin;9, second bending type fin;10, third bending fin;11, fourth bending fin. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantage of the utility model more clear and obvious, the following preferred embodiments are referred to the drawings and are given, and the utility model is further explained in detail. However, it is explained that, the many details listed in the specification are only for making the reader have a thorough understanding of one or more aspects of the utility model, and even without these specific details, the aspects of the utility model can be realized.

[0039] Referring to Figures 1 to 15 The utility model provides a kind of unequal thick pipe type heat spreader with boss, technical solutions are as follows:

[0040] As Figures 1-2 As shown in a kind of unequal thick pipe type heat spreader with boss, including by a piece of body and the cavity tube body formed after being connected by two sides. The cavity tube body includes upper tube body and lower tube body. The inside of upper tube body is provided with a plurality of first bosses, and a plurality of first bosses are formed by once forming by rolling of upper tube body. The inside of lower tube body is provided with a plurality of second bosses corresponding to first boss, and a plurality of second bosses are formed by once forming by rolling of lower tube body. Corresponding first boss and second boss are fixedly connected. Wherein, the radial dimension of first boss and second boss gradually decreases from bottom to top, and the end surface of top of first boss and second boss is horizontally arranged. The end surface of top of first boss is connected with the end surface of top of second boss. By setting first boss and second boss, the mounting strength of upper tube body and lower tube body is increased, so that the heat spreader made is not prone to deformation when installing and using, avoid the influence of heat dissipation performance due to tube body deformation, and because first boss and second boss are set, so that tube body can be made very thin, the structure of unequal thickness is formed between boss and the rest of tube body, thinner tube body is more conducive to heat dissipation, while having certain strength, ensure the strength while ensuring heat dissipation effect.

[0041] It should be noted that first boss and second boss are all formed by rolling and rolling equipment, such as Figure 3As shown, the rolling mill device comprises an upper roller and a lower roller, and the upper roller is provided with a first boss rolling groove group for rolling the first bosses. The first boss rolling groove group comprises two rows of first boss rolling groove rows arranged transversely on the upper roller. Each rolling groove row comprises a plurality of first boss rolling grooves arranged circumferentially on the upper roller, and the first boss rolling grooves are used for rolling the first bosses. In order to improve the uniformity of the overall strength of the pipe body, the first bosses are arranged in a strip shape, and the axial direction of the first bosses forms an angle with the axial direction of the pipe body, and the angle is 15-45°. In the same row, the adjacent two first bosses can be arranged in different axial directions to improve the uniformity of the strength distribution of the pipe body. The upper roller is also provided with a second boss rolling groove group for rolling the second bosses. The second boss rolling groove group is arranged in a spaced manner with the first boss rolling groove group, and the spacing is that the center line of the spacing is taken as the axis of symmetry, and the second boss rolling groove group is arranged in an axisymmetric manner with the first rolling groove group. The second boss rolling groove group comprises two rows of second boss rolling groove rows arranged transversely on the upper roller, and each second boss rolling groove row comprises a plurality of second boss rolling grooves arranged circumferentially on the upper roller, and the second boss rolling grooves are used for rolling the second bosses. The second boss rolling grooves are arranged in a corresponding manner with the first boss rolling grooves, and the first boss rolling grooves and the second boss rolling grooves arranged in a corresponding manner are arranged in an axisymmetric manner, so that the first bosses and the second bosses arranged in a symmetric manner can be prepared. The lower roller is arranged below the upper roller, and the surface of the lower roller is a smooth curved surface. When the sheet body passes between the upper roller and the lower roller, the sheet body is extruded by the lower roller, so that the area of the sheet body extruded by the upper roller without the first boss groove and the second boss groove is extruded. When the area of the sheet body is extruded, the extruded area of the sheet body is thinned, and the area of the sheet body corresponding to the first boss groove and the second boss groove is not extruded and thus maintains the thickness, forming the first boss and the second boss. That is, the thick pipe body part strengthens the overall pipe body strength, and the extruded thin part can improve the heat dissipation performance. Moreover, the pipe body can be made thinner and lighter, facilitating installation, and at the same time, having better heat dissipation performance.

[0042] The two ends of the upper pipe body are inwardly inclined and bent to form first bending parts, and the two ends of the lower pipe body are respectively inwardly bent to form second bending parts, and the first bending parts and the second bending parts are sealingly connected. The first bending parts and the second bending parts can be simultaneously pressed on the upper and lower sides of one end by a stamping device, so that the upper and lower sides of the end part are tightly attached, and then the tightly attached parts of the upper and lower sides are welded. The other end is similarly stamped and welded, so as to seal the two ends to form a uniform temperature plate. In the uniform temperature plate, the plurality of first bosses and second bosses are connected to improve the overall strength of the uniform temperature plate, so that the uniform temperature plate will not easily deform during installation and use to affect the heat dissipation effect, thereby ensuring the heat dissipation efficiency.

[0043] Further, the inner side wall of the upper tube body, the outer side wall of the first boss and the outer side wall of the second boss are further provided with a liquid absorbing core. Based on the capillary effect and the principle of liquid dynamics, when the liquid contacts the surface of the liquid absorbing core, due to the micro-pore structure inside the liquid absorbing core, the liquid is rapidly absorbed and diffused along the internal fiber network, forming a "wicking" phenomenon. This effect enables the liquid to return to the evaporation end under the action of gravity, thereby facilitating heat transfer and circulation. The liquid absorbing core includes a metal mesh type or a metal sintering type. The metal mesh type is to attach a certain mesh number of metal wire mesh to the inner side wall of the upper tube body and the outer side wall of the dotting groove. The metal sintering type includes powder sintering and fiber sintering. By providing the liquid absorbing core, the heat transfer rate and the cooling liquid circulation are improved, and the heat dissipation efficiency is further improved.

[0044] As shown in Figure 4 The outer side wall of the upper tube body is provided with a heat dissipation fin, and the heat dissipation fin is fixedly connected with the upper tube body. The heat dissipation fin includes a first fold line type fin group and a second fold line type fin group, the first fold line type fin group and the second fold line type fin group are alternately arranged along the transverse direction of the upper tube body, the first fold line type fin group includes a plurality of first fold line type fins arranged in sequence along the longitudinal direction of the upper tube body, and the plurality of first fold line type fins are connected in sequence, the second fold line type fin group includes a plurality of second fold line type fins arranged in sequence along the longitudinal direction of the upper tube body, and the plurality of second fold line type fins are connected in sequence, and the peak width of the first fold line type fin is arranged in a staggered manner with the peak of the second fold line type fin. The heat dissipation fin is in contact with the upper tube body, and the heat transfer of the upper tube body can be dissipated, thereby improving the heat dissipation effect. The peak width of the first fold line type fin of the heat dissipation fin is arranged in a staggered manner with the peak of the second fold line type fin, so that the first fold line type fin and the second fold line type fin form a staggered gap, air can flow through the staggered gap, and the heat dissipation effect of the heat dissipation fin is improved.

[0045] The utility model discloses still disclose a kind of preparation process of unequal thick tube type uniform temperature plate with boss, which comprises the following steps:

[0046] S1, selecting a planar substrate, rolling along the longitudinal direction of the planar substrate to form a first boss group and a second boss group on one side of the planar substrate, the first boss group and the second boss group are arranged in axial symmetry, wherein the first boss group includes at least one column of first boss columns composed of a plurality of first bosses arranged at intervals along the longitudinal direction of the planar substrate, and the second boss group includes at least one column of second boss columns composed of a plurality of second bosses arranged at intervals along the longitudinal direction of the planar substrate;

[0047] S2, the two sides of the flat base material after rolling are rolled to have connecting parts with curvature, the connecting parts are bent to the side with the boss, the middle part of the flat base material is rolled again, the connecting parts on the two sides of the flat base material are close to each other, a U-shaped material is formed, the rolling is continued until the connecting parts on the two sides are in contact, the connecting parts on the two sides are welded to form an O-shaped pipe body;

[0048] S3, the two opposite sides of the O-shaped pipe body are rolled until the corresponding first boss and the second boss are in contact, the O-shaped pipe body becomes an elliptical pipe body, the elliptical pipe body is cut to form a pipe body segment, the pipe body segment is cleaned and leak detection is performed;

[0049] S4, the contact part of the first boss and the second boss in the pipe body segment is welded, one end of the pipe body segment is stamped to make the upper and lower sides of the end part in close contact, and the contact part is welded to form a semi-sealed pipe body segment, a liquid is introduced into the open end of the semi-sealed pipe body segment for water test detection, and after the water test detection, the semi-sealed pipe body segment is vacuumized from the open end and the cooling liquid is injected;

[0050] S5, the open end of the semi-sealed pipe body segment is stamped and welded to seal both ends of the pipe body segment, forming a uniform temperature plate. Select the heat dissipation fins, tightly attach the heat dissipation fins to one of the outer side walls of the uniform temperature plate, and weld the contact part of the heat dissipation fins and the uniform temperature plate to fix the heat dissipation fins on the outer side wall of the uniform temperature plate.

[0051] By using the above preparation process, the process is simple, the boss only needs to be formed by rolling once, different columnar supports are not needed, the preparation efficiency of the uniform temperature plate is improved, the process cost output is reduced, and the uniform temperature plate with better heat dissipation performance can be prepared by using the process.

[0052] The utility model carries out comparison experiment:

[0053] Under the same external size (120mm*26mm T=2mm), compared with the aluminum plate, the O-shaped pipe without internal support and the harmonica pipe with internal columnar support, the same heat source is used, the heat source condition is: size (10mm*10mm) heat flow (50w), without cooling condition, two-second instantaneous performance, and the following table 1 is obtained:

[0054] Table 1

[0055]

[0056] In table 1, comparative example 1 is an aluminum plate, comparative example 2 is an O-shaped pipe, comparative example 3 is a harmonica pipe, and example 1 is the uniform temperature plate of the utility model. As can be seen from table 1, the heat source temperature of the uniform temperature plate of the application decreases obviously, the heat dissipation effect is remarkable, the weight is smaller, and the heat dissipation performance is better. The simulation cloud picture is as shown in Figures 5-8 .

[0057] Example 2

[0058] As Figure 9 shown, the utility model provides a kind of unequal thick pipe type heat sink with boss, and different from embodiment 1, in this embodiment, heat dissipation fin includes third fold line type fin group, third fold line type fin group includes multiple third fold line type fins sequentially arranged along the longitudinal direction of upper pipe body, multiple third fold line type fins are sequentially connected as a whole, and the wave crest of third fold line type fin is arranged in wave shape along the transverse direction of upper pipe body.Wave-shaped heat dissipation fin improves the space of air circulation, so that air can take away more heat of heat dissipation fin, to improve the heat dissipation effect.

[0059] Example 3

[0060] As Figure 10 shown, the utility model provides a kind of unequal thick pipe type heat sink with boss, and different from embodiment 1, in this embodiment, heat dissipation fin includes fourth fold line type fin group, fourth fold line type fin group includes multiple fourth fold line type fins sequentially arranged along the transverse direction of cavity pipe body, multiple fourth fold line type fins are sequentially connected as a whole, and the wave crest of fourth fold line type fin is arranged in straight line shape along the longitudinal direction of cavity pipe body.Straight line shape heat dissipation fin improves heat dissipation efficiency, but simple to make, facilitate production, improve production efficiency.

[0061] Comparative experiment is made in this embodiment:

[0062] Under the same external size (120mm×26mm T=2mm), compared with the combination of aluminum plate and heat dissipation fin, the combination of O-shaped pipe without internal support and heat dissipation fin and the combination of harmonica pipe with internal columnar support and heat dissipation fin, the same heat source is used, and the heat source condition is: size (10mm×10mm) heat flow (50w), without cooling condition, two-second instantaneous performance, to obtain the following table 2:

[0063] Table 2

[0064]

[0065] In table 2, comparative example 1 is the combination of aluminum plate and heat dissipation fin, comparative example 2 is the combination of O-shaped pipe and heat dissipation fin, comparative example 3 is the combination of harmonica pipe and heat dissipation fin, and example 1 is the combination of heat sink and heat dissipation fin of the utility model.It can be seen from table 2 that the combination of heat sink and heat dissipation fin of the application is obvious in heat source temperature drop, and the weight is smaller, and the heat dissipation performance is better than comparative examples 1-3.The simulation nephogram is as Figures 11-15 shown.

[0066] The above merely is preferred implementation manner of the present application, it should be pointed out, for ordinary skilled person in the technical field, on the premise of not departing from the principle of the present application, can also make several improvements and refinements, these improvements and refinements also should be regarded as the protection scope of the present application.

Claims

1. A non-uniform thickness tube type vapor chamber having a boss, characterized by, The cavity tube is formed by connecting two sides of a sheet body, and comprises an upper tube and a lower tube; A plurality of first bosses are arranged on the inner side of the upper tube, and a plurality of second bosses corresponding to the first bosses are arranged on the inner side of the lower tube, and the first bosses are fixedly connected with the corresponding second bosses; The two ends of the upper tube are respectively inwardly inclined and curved to form first bending portions, and the two ends of the lower tube are respectively inwardly curved to form second bending portions, and the first bending portions are sealingly connected with the second bending portions.

2. The unequal thickness tube type vapor chamber with a boss according to claim 1, characterized in that: The radial dimension of the first boss and the second boss gradually decreases from the bottom to the top, and the end face of the top of the first boss and the top of the second boss is horizontally arranged.

3. The unequal thickness tube type vapor chamber with a boss according to claim 2, characterized in that: The end face of the top of the first boss is connected with the end face of the top of the second boss.

4. The unequal thickness tube type vapor chamber with a boss according to claim 1, characterized in that: An absorbent core is further arranged on the inner side wall of the upper tube and the outer side wall of the first boss and the second boss.

5. The unequal thickness tube type vapor chamber with a boss according to claim 1, characterized in that: A heat dissipation fin is arranged on the outer side wall of the upper tube, and the heat dissipation fin is fixedly connected with the upper tube.

6. The unequal thickness tube type vapor chamber with a boss according to claim 5, characterized in that: The heat dissipation fin comprises a first fold line type fin group and a second fold line type fin group, and the first fold line type fin group and the second fold line type fin group are alternately arranged along the transverse direction of the upper tube; The first fold line type fin group comprises a plurality of first fold line type fins arranged in sequence along the longitudinal direction of the upper tube, and the plurality of first fold line type fins are sequentially connected as a whole. The second fold line type fin group comprises a plurality of second fold line type fins arranged in sequence along the longitudinal direction of the upper tube, and the plurality of second fold line type fins are sequentially connected as a whole. The wave crest of the first fold line type fin is arranged in a staggered manner with the wave crest of the second fold line type fin.

7. The unequal thickness tube type vapor chamber with a boss according to claim 5, characterized in that: The heat dissipation fin comprises a third fold line type fin group, the third fold line type fin group comprises a plurality of third fold line type fins arranged in sequence along the longitudinal direction of the upper tube, and the plurality of third fold line type fins are sequentially connected as a whole, and the wave crest of the third fold line type fin is arranged in a wave shape along the transverse direction of the upper tube.

8. The unequal thickness tube type vapor chamber with a boss according to claim 5, characterized in that: The heat dissipation fin comprises a fourth fold line type fin group, the fourth fold line type fin group comprises a plurality of fourth fold line type fins arranged in sequence along the transverse direction of the upper tube, and the plurality of fourth fold line type fins are sequentially connected as a whole, and the wave crest of the fourth fold line type fin is arranged in a straight line along the longitudinal direction of the upper tube.

Images