Spiral outer finned tube and machining tool and machining method thereof

Abstract

The invention relates to a spiral outer finned tube and a machining tool and method thereof. The machining tool comprises a cutting edge. A guide part is arranged on one side of the cutting edge, and a guide groove vertically extending upwards is formed between the guide part and the cutting edge; the bottom end of the guide part is higher than the bottom end of the blade, and a guide groove inlet is formed between the bottom end of the guide part and the bottom end of the blade. When the fins are planed, the guide grooves extending vertically and upwards force the fins to extend vertically and upwards, curling is avoided, and therefore the maximum height of the fins can be increased, and the higher fins can be manufactured. According to the machining method for the spiral three-dimensional outer finned tube, the spiral three-dimensional outer finned tube can be precisely machined, the fins are distributed in a spiral blade shape in the circumferential direction and distributed in a spiral shape in the axial direction, and the specific shape and size can be freely adjusted within a certain range.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical manufacturing, in particular to a spiral external fin tube and a machining tool and a machining method thereof. Background Art

[0002] The external finned tubes used in industry are mainly two-dimensional structures, such as sleeve finned tubes, wound finned tubes, and rolled finned tubes. With the rapid development of processing technology, three-dimensional external finned tubes, which belong to the third generation of heat transfer technology, have been widely used in the field of heat exchangers. Compared with one-dimensional and two-dimensional external finned tubes, three-dimensional external finned tubes have a rougher surface, a larger heat exchange area, enhanced heat transfer function, energy saving and consumption reduction, and belong to the green energy-saving product structure.

[0003] In the current three-dimensional external fin tube, the fins are usually evenly distributed on the outer wall of the copper tube body in a circular array. The spoiler surface of the fin is perpendicular to the direction of the fluid, which blocks the rear fins and makes the rear fins insufficiently contact with the fluid, affecting the further improvement of the heat exchange efficiency. In addition, the existing three-dimensional external fin planing process is prone to curling when processing higher fins due to the thin fins, which limits the maximum height of the fins. Summary of the invention

[0004] In view of the problems existing in the prior art, the purpose of the present invention is to provide a spiral external fin tube with a relatively high fin height. When the fluid passes through the outer surface of the fin tube, the fluid can be guided to spirally move forward and fully contact the fins, thereby increasing the fluid heat exchange stroke and improving the heat exchange efficiency; at the same time, a processing tool and a processing method are provided, which can process a spiral three-dimensional external fin tube, so that the processed high fins will not curl, thereby increasing the maximum height of the fins.

[0005] In order to achieve the above object, the present invention adopts the following technical solution: A machining tool comprises a cutting edge; A guide portion is provided on one side of the blade, and a guide groove extending vertically upward is formed between the guide portion and the blade; The bottom end of the guide portion is higher than the bottom end of the blade, and a guide groove entrance is formed between the bottom end of the guide portion and the bottom end of the blade.

[0006] Furthermore, the width of the upper portion of the guide groove is greater than the width of the entrance of the guide groove.

[0007] Furthermore, the guide groove includes a front side wall and a rear side wall which are parallel to each other, the top of the blade is inclined and the distance between the top of the blade and the front side wall of the guide groove gradually increases from bottom to top, and the rear side wall of the guide groove extends vertically upward along the top of the blade.

[0008] Furthermore, two blades are provided, and the two blades are respectively provided at two ends of the tool, and the two blades are provided with corresponding guide parts and guide grooves.

[0009] A method for processing a spiral external finned tube comprises the following steps: The tool and the copper tube are respectively mounted on a three-axis linkage lathe, and the tool blade forms a certain angle with the axial direction of the copper tube; The tool is fed in axial and radial directions of the copper tube, and the copper tube rotates in tandem. When the tool blade contacts the copper tube, fins are planed on the steel tube. As the processing progresses, the fins extend upward from the entrance of the guide groove into the guide groove. Under the constraint of the vertically extending guide groove, the fins are perpendicular to the copper tube. After completing one fin processing on the copper tube, the tool first retracts radially and then axially, while the copper tube rotates and resets; After the single fin processing is completed and reset, the copper tube rotates a step Δ c1 , and then repeat the above processing steps until a circle of fins is processed and reset; The next circle of fins is processed according to the above processing steps until all fins are processed to obtain a spiral external fin tube.

[0010] Furthermore, during the tool feeding process, the axial feed amount S of the tool z and the rotation amount of the cutting tool θ c Satisfies the following relationship, ; Among them, k is the deflection angle between the tool edge and the axial direction of the copper tube, and d is the base diameter of the copper tube.

[0011] Furthermore, after one fin circle is processed, the copper tube is rotated by a step distance Δ before the next fin circle is processed. c2 , and the tool is withdrawn axially by a circle spacing Δ z , and then start processing the next circle of fins.

[0012] Further, the tool and the copper tube are respectively mounted on the three-axis linkage lathe, including: The tool is clamped together by the inclined pad and the inclined pressure block on the lathe, wherein the inclined surface angles of the inclined pad and the inclined pressure block are equal to the tool deflection angle k; the copper tube body is clamped by the chuck jaws of the lathe, and the end face of the steel tube is pressed tightly by the top of the lathe.

[0013] A spiral external fin tube comprises a copper tube and a plurality of fin groups; A plurality of fin groups are respectively arranged on the outer wall of the copper tube, and the plurality of fin groups are parallel to each other; Each fin group is spirally arranged along the axial direction of the copper tube, and each fin group includes a plurality of fins arranged at intervals; Each fin is perpendicular to the outer wall of the copper tube.

[0014] Furthermore, the spoiler surface of each fin has a deviation angle k with the axial direction of the copper tube.

[0015] In general, the present invention has the following advantages: 1. The spiral three-dimensional external finned tube provided by the present invention has fins distributed in a spiral shape. When the fluid passes through the outer surface of the finned tube, the fluid can be guided to move forward in a spiral shape and fully contact the fins, thereby improving the heat exchange efficiency.

[0016] 2. The spiral three-dimensional external fin tube processing tool provided by the present invention has a vertically extending guide groove at the front end of the blade. When planing the fins, the fins are forced to extend vertically upward to avoid curling, thereby increasing the maximum height of the fins and preparing taller fins.

[0017] 3. The spiral three-dimensional external finned tube processing method provided by the present invention can accurately process a spiral three-dimensional external finned tube, the fins are distributed in the shape of spiral blades along the circumference and in a spiral shape along the axial direction, and the specific shape and size can be freely adjusted within a certain range. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is an isometric view of the spiral three-dimensional external fin tube of the present invention.

[0019] Figure 2 (a) is a front view of a spiral three-dimensional external fin tube.

[0020] Figure 2 (b) is a left view of the spiral three-dimensional external fin tube.

[0021] Figure 3 Schematic diagram of fluid flow on the surface of spiral three-dimensional external finned tube.

[0022] Figure 4 These are the main parameters of the fin morphology of the spiral three-dimensional external finned tube.

[0023] Figure 5 (a) is an axonometric view of the fin machining tool.

[0024] Figure 5(b) is a right view of the fin processing tool.

[0025] FIG5(c) is an enlarged schematic diagram of point A in FIG5(a).

[0026] Figure 6 (a) is a schematic diagram of the spiral fin processing principle-initial state.

[0027] Figure 6 (b) is a schematic diagram of the initial state of the spiral fin processing principle from another perspective.

[0028] Figure 7 (a) shows the spiral fin processing principle - processing one fin.

[0029] FIG7( b ) is an enlarged schematic diagram of point B in FIG7( a ).

[0030] Figure 8 It is the processing principle of spiral fins - tool retraction and reset.

[0031] Fig. 9 It is the processing principle of spiral fins - completing one circle of fin processing.

[0032] Figure 10 (a) shows the processing principle of spiral fins - processing the next circle of fins.

[0033] FIG10( b ) is an enlarged schematic diagram of point C in FIG10( a ).

[0034] Figure 11 (a) is a schematic diagram of the structure processed using a CNC lathe.

[0035] Figure 11(b) is a front view of the part processed using a CNC lathe.

[0036] Figure 11(c) is a top view of the processing using a CNC lathe.

[0037] In the figure: 1- turret, 2- inclined pad, 3- inclined pressure block, 4- tool, 41- blade, 42- guide part, 43- guide groove, 5- tip, 6- copper tube, 7- chuck jaw, 8- bolt, 9- fin, 91- spoiler surface. DETAILED DESCRIPTION

[0038] The present invention will be described in further detail below.

[0039] like Figure 1 The isometric view of the spiral three-dimensional external fin tube is shown in FIG2 (a) and FIG2 (b), which are the front view and the left view of the spiral three-dimensional external fin tube, respectively. The spoiler surface 91 of the fin 9 is at a certain angle to the axial direction of the copper tube 6. Each circle of fins 9 is distributed in a circular array along the axial direction of the fin tube, that is, it is distributed in the shape of spiral blades in the circumferential direction. There is a fixed angle difference between two adjacent circles of fins 9 to ensure that the spoiler surface 91 of the fin 9 is aligned, so that the spoiler surface 91 of the fin 9 is arranged in the axial direction to form a spiral shape as a whole.

[0040] like Figure 3 The figure shows the flow of fluid on the surface of the spiral three-dimensional external fin tube. When the fluid flows axially on the outer surface, because the spoiler surface 91 of the fin 9 is arranged in a spiral shape, the fluid flows in a spiral along the spoiler surface 91, so that the fluid can fully contact the surface of the fin 9, and the heat exchange stroke of the fluid is increased, thereby improving the heat exchange efficiency.

[0041] like Figure 4 The main factors affecting the morphology of the spiral three-dimensional external fin tube fin 9 are shown below: (1) Fin helix angle β (2) Fin height h (3) Number of fins per circle n (4) Distance between two adjacent circles Δ z (5) Base pipe diameter d As shown in Figures 5(a), 5(b) and 5(c), a processing tool 4 for processing a spiral three-dimensional external finned tube includes a blade 41; a guide portion 42 is provided in front of the blade 41, and a guide groove 43 extending vertically upward is formed between the guide portion 42 and the blade 41; the bottom end of the guide portion 42 is higher than the bottom end of the blade 41, and an entrance to the guide groove 43 is formed between the bottom end of the guide portion 42 and the bottom end of the blade 41.

[0042] When the blade 41 of the tool 4 planes out the fin 9 on the copper tube 6, the fin 9 enters the guide groove 43 from the entrance thereof and is constrained by the guide groove 43 to remain in a vertical state without bending, thereby being able to prepare a higher fin 9.

[0043] The width of the upper portion of the guide groove 43 is greater than the width of the entrance of the guide groove 43. The narrower entrance width of the guide groove 43 is conducive to keeping the planed fins 9 at a vertical angle to the copper tube 6, and the wider upper width of the guide groove 43 is conducive to fully extending the fins 9 upward to form higher fins 9.

[0044] Specifically, the guide groove 43 includes a front side wall and a rear side wall parallel to each other. The top of the blade 41 is tilted backward and upward, and the distance between it and the front side wall of the guide groove 43 gradually increases from bottom to top. The rear side wall of the guide groove 43 extends vertically upward along the top of the blade 41.

[0045] The main factors affecting the shape of the fin 9 machining tool 4 include: (1) Knife thickness (2) Rake angle γ (3) Back angle α (4) Blade spacing Δ t (5) Groove height h s (6) Groove width h w (7) Guide width b w In this embodiment, two blades 41 are provided. The two blades 41 are respectively provided at two ends of the tool 4. The two blades 41 are both provided with corresponding guide portions 42 and guide grooves 43. The two blades 41 can be switched for use to increase the service life.

[0046] Figures 6 (a) and 6 (b) show the initial state before the fin 9 is processed by the fin processing tool 4. The tool 4 is placed at a certain angle (angle k) to the axis of the copper tube 6 to be processed, and the tool 4 is close to the copper tube 6 but not in contact. The specific processing steps are as follows: (1) As shown in Figures 7(a) and 7(b), three-axis linkage is required during processing. The tool 4 is fed in an axial and radial direction of the copper tube 6 (in the direction shown in the figure), and the copper tube 6 is rotated in a coordinated manner (in the direction shown in the figure). Because the blade 41 of the tool 4 is at a certain angle to the axial direction of the copper tube 6 ( ), when the tool 4 contacts the copper tube 6, a planing motion is formed to plan the fin 9. To ensure that the blade 41 is perpendicular to the actual cutting direction and the fin 9 is roughly perpendicular to the surface of the copper tube 6, the axial feed amount S during the feeding process is z and the rotation amount of the cutting tool θ c The following relationship should be satisfied: ; Wherein, k is the deflection angle between the blade 41 of the tool 4 and the axial direction of the copper tube 6 , and d is the base tube diameter of the copper tube 6 .

[0047] After the fin 9 is planed, the fin 9 enters the guide groove 43 and is constrained by the guide groove 43 to avoid bending. After feeding to the end point, the processing of one fin 9 is completed.

[0048] (2) If Figure 8 As shown, after completing the processing of one fin 9, the tool 4 is first retracted in the radial direction and then in the axial direction, and at the same time, the rotation angle of the copper tube 6 is also reset.

[0049] (3) If Fig. 9 As shown, after the single fin 9 is processed and reset, the copper tube 6 rotates a step Δ c1 , and then repeat step (1) until a circle of fins 9 is processed and reset.

[0050] (4) As shown in Figure 10 (a) and Figure 10 (b), in order to make the fins 9 spirally distributed along the axial direction, the initial position of the next circle of fins 9 should have an angle difference with the previous circle of fins 9. Therefore, before starting the next circle of fins 9, the copper tube 6 rotates a step distance Δ c2 At the same time, tool 4 is first withdrawn axially by a circle spacing Δ z , and then repeat step (1) until all fins 9 are processed.

[0051] Figures 11(a), 11(b) and 11(c) show the specific structural principle diagrams of the implementation using a three-axis linkage CNC lathe (X, Z, C three-axis linkage). (Except for the turret 1 and the chuck jaw 7, the rest of the CNC lathe parts are not drawn. Any CNC lathe capable of X, Z, C three-axis linkage can implement this example) The inclined pressing block 3 is fastened to the lathe by bolts 8, and the tool 4 is clamped together by the inclined pad block 2 and the inclined pressing block 3 on the lathe turret 1, wherein the inclined angles of the inclined pad block 2 and the inclined pressing block 3 are equal to the deflection angle k of the tool 4; the copper tube 6 is clamped by the chuck jaws 7 of the lathe, and the end face of the steel tube is pressed by the center 5 of the lathe. The above processing steps are realized by the three-axis linkage of the CNC lathe.

[0052] A spiral external fin tube is prepared by the above processing method, comprising a copper tube 6, the outer wall of the copper tube 6 has a plurality of fin groups, and the plurality of fin groups are parallel to each other; Each fin group is spirally arranged along the axial direction of the copper tube 6, and each fin group includes a plurality of fins 9 arranged at intervals; Each fin 9 is perpendicular to the outer wall of the copper tube 6 , and a spoiler surface 91 of each fin 9 has an angle k with the axial direction of the copper tube 6 .

[0053] (1) Example 1: Example 1 is carried out using the above structure, and the parameters of the tool 4 are as follows: Parameter name symbol Numeric unit Thickness t 2 mm Front Angle γ 5 °(degree) Rear Angle α 20 °(degree) Blade spacing <![CDATA[Δ t ]]> 0.6 mm Groove height <![CDATA[h s ]]> 8 mm Slot width <![CDATA[h w ]]> 1.4 mm Guide width <![CDATA[b w ]]> 1.1 mm The processing parameters are as follows: Parameter name symbol Numeric unit Base pipe diameter d 20 mm Declination k 40 °(degree) Axial feed amount <![CDATA[S z ]]> 6 mm Radial feed <![CDATA[S x ]]> 0.4 mm Rotary feed <![CDATA[θ c ]]> 28.861 °(degree) Rotation step 1 <![CDATA[Δ c1 ]]> 22.5 °(degree) Rotation step 2 <![CDATA[Δ c2 ]]> 13.663 °(degree) Circle spacing <![CDATA[Δ z ]]> 2 mm The fin 9 size parameters obtained after processing according to the above steps are as follows: Parameter name symbol Numeric unit Helix Angle β 50 °(degree) Wing height h 6 mm number of wings n 16 indivual Circle spacing <![CDATA[Δ z ]]> 2 mm Base pipe diameter d 20 mm (2) Example 2: Example 2 is carried out using the above structure, and the parameters of the tool 4 are as follows: Parameter name symbol Numeric unit Thickness t 2 mm Front Angle γ 10 °(degree) Rear Angle α 20 °(degree) Blade spacing <![CDATA[Δ t ]]> 0.6 mm Groove height <![CDATA[h s ]]> 8 mm Slot width <![CDATA[h w ]]> 1.5 mm Guide width <![CDATA[b w ]]> 1.0 mm The processing parameters are as follows: Parameter name symbol Numeric unit Base pipe diameter d 20 mm Declination k 30 °(degree) Axial feed amount <![CDATA[S z ]]> 5 mm Radial feed <![CDATA[S x ]]> 0.4 mm Rotary feed <![CDATA[θ c ]]> 16.548 °(degree) Rotation step 1 <![CDATA[Δ c1 ]]> 22.5 °(degree) Rotation step 2 <![CDATA[Δ c2 ]]> 19.858 °(degree) Circle spacing <![CDATA[Δ z ]]> 2 mm The fin 9 size parameters obtained after processing according to the above steps are as follows: Parameter name symbol Numeric unit Helix Angle β 60 °(degree) Wing height h 5 mm number of wings n 16 indivual Circle spacing <![CDATA[Δ z ]]> 2 mm Base pipe diameter d 20 mm (3) Example 3: Example 3 is carried out using the above structure, and the parameters of the tool 4 are as follows: Parameter name symbol Numeric unit Thickness t 2 mm Front Angle γ 15 °(degree) Rear Angle α 20 °(degree) Blade spacing <![CDATA[Δ t ]]> 0.6 mm Groove height <![CDATA[h s ]]> 8 mm Slot width <![CDATA[h w ]]> 1.5 mm Guide width <![CDATA[b w ]]> 1.0 mm The processing parameters are as follows: Parameter name symbol Numeric unit Base pipe diameter d 20 mm Declination k 20 °(degree) Axial feed amount <![CDATA[S z ]]> 4 mm Radial feed <![CDATA[S x ]]> 0.4 mm Rotary feed <![CDATA[θ c ]]> 8.346 °(degree) Rotation step 1 <![CDATA[Δ c1 ]]> 22.5 °(degree) Rotation step 2 <![CDATA[Δ c2 ]]> 23.625 °(degree) Circle spacing <![CDATA[Δ z ]]> 1.5 mm The fin 9 size parameters obtained after processing according to the above steps are as follows: Parameter name symbol Numeric unit Helix Angle β 70 °(degree) Wing height h 4 mm number of wings n 16 indivual Circle spacing <![CDATA[Δ z ]]> 1.5 mm Base pipe diameter d 20 mm The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A machining tool, characterized in that: Including blades; A guide portion is provided on one side of the blade, and a guide groove extending vertically upward is formed between the guide portion and the blade; The bottom end of the guide portion is higher than the bottom end of the blade, and a guide groove entrance is formed between the bottom end of the guide portion and the bottom end of the blade.

2. A machining tool according to claim 1, characterized in that: The width of the upper portion of the guide groove is greater than the width of the entrance of the guide groove.

3. A machining tool according to claim 1, characterized in that: The guide groove comprises a front side wall and a rear side wall which are parallel to each other. The top of the blade is inclined and the distance between the top of the blade and the front side wall of the guide groove gradually increases from bottom to top. The rear side wall of the guide groove vertically extends upward along the top of the blade.

4. A machining tool according to claim 1, characterized in that: There are two blades, which are respectively arranged at two ends of the tool, and both blades are provided with corresponding guide parts and guide grooves.

5. A method for processing a spiral external finned tube, characterized in that: Using the machining tool described in any one of claims 1 to 4, The following steps are included: The tool and the copper tube are respectively mounted on a three-axis linkage lathe, and the tool blade forms a certain angle with the axial direction of the copper tube; The tool is fed in axial and radial directions of the copper tube, and the copper tube rotates in tandem. When the tool blade contacts the copper tube, fins are planed on the steel tube. As the processing progresses, the fins extend upward from the entrance of the guide groove into the guide groove. Under the constraint of the vertically extending guide groove, the fins are perpendicular to the copper tube. After completing one fin processing on the copper tube, the tool first retracts radially and then axially, while the copper tube rotates and resets; After the single fin processing is completed and reset, the copper tube rotates a step Δ c1 , and then repeat the above processing steps until a circle of fins is processed and reset; The next circle of fins is processed according to the above processing steps until all fins are processed to obtain a spiral external fin tube.

6. A processing method according to claim 5, characterized in that: During the tool feeding process, the axial feed amount S of the tool z and the rotation amount of the cutting tool θ c Satisfies the following relationship, ； Among them, k is the deflection angle between the tool edge and the axial direction of the copper tube, and d is the base diameter of the copper tube.

7. A processing method according to claim 5, characterized in that: After completing one circle of fin processing, before starting the next circle of fin processing, the copper tube rotates a step distance Δ c2 , and the tool is withdrawn axially by a circle spacing Δ z , and then start processing the next circle of fins.

8. A processing method according to claim 5, characterized in that: Installing the tool and copper tube on the three-axis linkage lathe includes: The tool is clamped together by the inclined pad and the inclined pressure block on the lathe, wherein the inclined surface angles of the inclined pad and the inclined pressure block are equal to the tool deflection angle k; the copper tube body is clamped by the chuck jaws of the lathe, and the end face of the steel tube is pressed tightly by the top of the lathe.

9. A spiral external fin tube, characterized in that: Prepared by the processing method described in any one of claims 5 to 8, comprising a copper tube and a plurality of fin groups; A plurality of fin groups are respectively arranged on the outer wall of the copper tube, and the plurality of fin groups are parallel to each other; Each fin group is spirally arranged along the axial direction of the copper tube, and each fin group includes a plurality of fins arranged at intervals; Each fin is perpendicular to the outer wall of the copper tube.

10. The spiral external fin tube according to claim 9, characterized in that: The spoiler surface of each fin has a deviation angle k with the axial direction of the copper tube.

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