US20140215825A1 - Method and apparatus for manufacturing fin-integrated tube for use in heat exchanger - Google Patents
Method and apparatus for manufacturing fin-integrated tube for use in heat exchanger Download PDFInfo
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- US20140215825A1 US20140215825A1 US14/099,303 US201314099303A US2014215825A1 US 20140215825 A1 US20140215825 A1 US 20140215825A1 US 201314099303 A US201314099303 A US 201314099303A US 2014215825 A1 US2014215825 A1 US 2014215825A1
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- Prior art keywords
- tube
- rolling
- roller
- fin
- periphery
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D53/00—Making other particular articles
- B21D53/02—Making other particular articles heat exchangers or parts thereof, e.g. radiators, condensers fins, headers
- B21D53/06—Making other particular articles heat exchangers or parts thereof, e.g. radiators, condensers fins, headers of metal tubes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
- B21C37/06—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of tubes or metal hoses; Combined procedures for making tubes, e.g. for making multi-wall tubes
- B21C37/15—Making tubes of special shape; Making tube fittings
- B21C37/22—Making finned or ribbed tubes by fixing strip or like material to tubes
- B21C37/26—Making finned or ribbed tubes by fixing strip or like material to tubes helically-ribbed tubes
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/4935—Heat exchanger or boiler making
- Y10T29/49377—Tube with heat transfer means
- Y10T29/49378—Finned tube
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/53—Means to assemble or disassemble
- Y10T29/53113—Heat exchanger
- Y10T29/53122—Heat exchanger including deforming means
Definitions
- the present invention relates to a method and an apparatus for manufacturing a high temperature-resistant fin-integrated tube for use in a heat-exchanger mountable on a vehicle.
- FIG. 19 shows a common fin-integrated tube for use in a heat exchanger.
- This fin-integrated tube includes a tube 200 through which heat-exchanging medium flows and a plurality of hat-shaped rings 201 brazed to the tube 200 such that the tube 200 passes through a stack of the hat-shaped rings 201 as fins 202 .
- the exhaust heat recovery device As a heat exchanger mountable on a vehicle, the exhaust heat recovery device is receiving attention.
- the exhaust heat recovery device recovers exhaust heat emitted from an engine.
- the exhaust heat recovery device includes a fin-integrated tube which contains pure water and is mounted in the exhaust passage of the engine for recovering the exhaust heat. Since this fin-integrated tube is exposed to exhaust gas, it is made of heat-resistant and corrosion-resistant stainless steel and their fins are joined to the tube using a nickel-based brazing material, for example.
- the fins of such a fin-integrated tube may be deformed due to a linear expansion difference in the dissimilar metal joint by the brazing material in a case of a high-efficiency engine that emits high-temperature exhaust gas (900° C., for example). Further, if the number of the fins is increased to increase the heat exchange efficiency, manufacturing time and cost increase greatly because the fins have to be joined one by one to the tube.
- the inventors of the present invention studied a possibility of adoption of a fin-integrated tube which does not include any brazing material, and can be manufactured by the method described in the above patent document.
- the method of carving the tube surface to form fins as described in the above patent document which is suitable for the case where the tube is made of metal easy to carve such as aluminum, is difficult to use in the case where the tube is made of stainless steel.
- the wall thickness and the rigidity of the tube have to be sufficiently large, while on the other hand, the shapes of the fins formed by carving the outer or inner surface of the tube along its axis and the wall thickness after the carving of the tube are likely to be non-uniform. Hence, it is difficult to reduce individual difference in the radiation performance. As explained above, it has been difficult so far to achieve both reducing the manufacturing cost and increasing the heat exchange efficiency.
- An exemplary embodiment provides a method of manufacturing a fin-integrated tube for a heat exchanger, the fin-integrated tube including a cylindrical tube and a spiral fin integrally formed in a periphery of the tube, including the steps of:
- a rolling roller group including a plurality of rolling rollers each having a plurality of roller crests on a periphery thereof so as to surround the periphery of the tube with a predetermined lead angle, each of the roller crests being rounded at an end thereof into an R-shape to be an R-shaped end, widths of the R-shaped ends of the roller crests being gradually increased from one axial end to the other axial end for each of the rolling rollers, so that each of the rolling rollers serves as a gradual roller; and
- roller crests of the rolling rollers to press the periphery of the tube from the one axial end to the other axial end by axially moving and rotating the rolling roller group relative to the tube so as to deform a part of the periphery of the tube into a spirally projecting portion while shaping the spirally projecting portion into the spiral fin by gradually squeezing the part of the periphery of the tube using the R-shaped end portions of the roller crests of the rolling rollers.
- the exemplary embodiment provides also a manufacturing apparatus for manufacturing a fin-integrated tube for a heat exchanger, the fin-integrated tube including a cylindrical tube and a spiral fin integrally formed in a periphery of the tube, including:
- a tube holding part for holding a proximal end portion of the tube so as to be rotatable together with the tube
- a rolling roller head disposed coaxially with the tube so as to be axially movable relative to the tube;
- the rolling roller head having a rolling roller group including a plurality of rolling rollers each having a plurality of roller crests on a periphery thereof, said rolling roller group being configured to surround the periphery of the tube with a predetermined lead angle,
- each of the roller crests being rounded at an end thereof into an R-shape to be an R-shaped end, widths of the R-shaped ends of the roller crests being gradually increased from one axial end to the other axial end for each of the rolling rollers, so that each of the rolling rollers serves as a gradual roller,
- the rolling roller head is configured to be driven to axially move in a direction from a distal end to a proximal end of the tube and rotate relative to the tube so as to cause the roller crests of the rolling rollers to press the periphery of the tube in the direction from the distal end to the proximal end so as to deform a part of the periphery of the tube into a spirally projecting portion while shaping the spirally projecting portion into the spiral fin by gradually squeezing the part of the periphery of the tube using the R-shaped end portions of the roller crests of the rolling rollers.
- a high-performance and low-cost heat exchanger for vehicle use which includes fin-integrate tubes manufactured without use of brazing material.
- FIG. 1 is a general view of a manufacturing apparatus for manufacturing a fin-integrated tube according to a first embodiment of the invention
- FIG. 2 is a partially enlarged view of the fin-integrated tube manufactured by a method performed using the manufacturing apparatus according to the first embodiment of the invention
- FIG. 3 is a partially enlarged view of a form rolling part of the manufacturing apparatus according to the first embodiment of the invention.
- FIG. 4 is plan and side views of a form rolling roller head constituting the rolling part
- FIG. 5 is a partially enlarged view of an exhaust heat recovery device including the fin-integrated tubes manufactured by the method performed using the manufacturing apparatus according to the first embodiment of the invention
- FIG. 6 is a cross-sectional view of the exhaust heat recovery device
- FIG. 7 is a perspective view of the exhaust heat recovery device
- FIG. 8 is a schematic diagram for explaining a rolling process performed using the rolling roller head of the rolling part of the manufacturing apparatus according to the first embodiment of the invention.
- FIG. 9 is a diagram showing an example of the shapes of the roller crests of rolling rollers of the rolling roller head.
- FIGS. 10 and 11 are schematic diagrams for explaining a fin shaping process performed using the rolling rollers
- FIG. 12 is a schematic diagram for explaining variation of effect of the rolling rollers depending on variation of the angles of the roller crests of the rolling rollers;
- FIG. 13 is a schematic diagram for explaining variation of the effect of the rolling rollers depending on variation of the R-shaped end portions of the roller crests of the rolling rollers;
- FIG. 14 is a schematic diagram for explaining a tube extension at the time of the rolling process
- FIG. 15 is a cross-sectional view for explaining effects of a extension absorbing mechanism of the rolling roller head
- FIG. 16 is a side view showing an example of the shapes of the roller crests of rolling rollers of a manufacturing apparatus according to a second embodiment of the invention.
- FIG. 17 is a schematic diagram for explaining a tube forming process performed using the rolling rollers of the manufacturing apparatus according to the second embodiment of the invention.
- FIG. 18 is a schematic diagram for explaining a method of manufacturing a fin-integrated tube performed using a cored bar as a third embodiment of the invention.
- FIG. 19 is a perspective view of a conventional fin-integrated tube.
- FIG. 1 is a general view of a manufacturing apparatus according to a first embodiment of the invention, which manufactures a fin-integrated tube 2 shown in FIG. 2 .
- the fin-integrated tube 2 is used for various vehicle-mounted heat exchangers.
- the fin-integrated tube 2 is made from a cylindrical tube material 2 ′.
- the tube material 2 ′ is plastic-deformed by a rolling roller head 4 of a form rolling part 6 to form the fin-integrated tube 2 including a tube 21 and a fin 22 wound spirally on the outer periphery of the tube 21 at a predetermined pitch.
- FIG. 3 is a partially enlarged view of the form rolling part 6 which is a main part of the manufacturing apparatus.
- FIG. 4 is plan and side views of the rolling roller head 4 of the form rolling part 6 .
- FIG. 5 is a partially enlarged view of an exhaust heat recovery device including the fin-integrated tubes 2 .
- FIG. 6 is a cross-sectional view of the exhaust heat recovery device.
- FIG. 7 is a perspective view of the exhaust heat recovery device.
- the heat recovery device is for recovering exhaust heat emitted from an engine, and exchanging heat with engine cooling water.
- the exhaust heat recovery device is used for warming the engine to increase fuel economy.
- the exhaust heat recovery device includes a heating section (heat exchanging section) 1 housing a plurality of the fin-integrated tubes 2 , a heat guard 100 above which a tank is disposed, and a condensing section 101 having a LCC pipe P through which the engine cooling water (LLC) flows.
- LLC engine cooling water
- the heating section 1 is mounted inside a duct D provided midway of the exhaust passage of the engine.
- the condensing section 101 is disposed in the upper space of the tank.
- the heating section 1 and the condensing section 101 are loop-connected to each other through a steam passage 102 and a valve 103 to constitute a loop heat pipe (heat loop) enclosing working medium.
- the loop heat pipe operates to transfer heat by evaporation and condensation of the working medium.
- pure water is used as the working medium.
- the heating section 1 includes a plurality of the fin-integrated tubes 2 which are arranged in rows along the flow direction of the exhaust gas and in rows along the direction perpendicular to the flow direction of the exhaust gas within the duct D.
- Each of the fin-integrated tubes 2 includes the tube 21 extending in the direction perpendicular to the flow direction of the exhaust gas and the spiral fin 22 projecting radially outward from the periphery of the tube 21 .
- the bottom end of the tube 21 is closed, and the top end of the tube 21 penetrates through a core plate 3 forming the bottom plate of the tank and opens to the lower space in the tank.
- the inside of the tank is partitioned into the upper space and the lower space by a tank inner 4 .
- the tank inner 4 is formed with the steam passage 102 projecting upward.
- the lower space to which the fin-integrated tubes 2 open and the upper space in which the condensing section 101 is disposed are in communication through the steam passage 102 .
- the steam introduced from the steam passage 102 into the condensing section 101 exchanges heat with the engine cooling water by contacting with the LLC pipe, and becomes condensed water.
- the condensed water is refluxed back to the heating section 1 by opening or closing the valve 103 depending on the pressure inside the tank.
- a partition 105 having an oxygen introducing hole 104 is provided in the lateral direction of the steam passage 102 for removing oxygen generated by contact between high-temperature steam and metal, for example.
- a copper oxide containing case 106 containing granular copper oxide 107 is provided below the space partitioned by the partition 105 .
- the generated hydrogen is guided from the hydrogen introducing hole 104 to the copper oxide containing case 106 , and reduced to be removed.
- the fin 22 is integrally connected to the tube 21 at its proximal end portion, and exchanges heat with the exhaust gas contacting the fin surface at its thin distal end portion which is spirally joined to the tube 21 in layers at a predetermined fin pitch (Fp) in the axial direction of the tube 21 .
- the fin-integrated tube 2 is exposed to high-temperature exhaust gas in the duct D. Accordingly, the fin-integrated tube 2 is made of a heat-resistant and oxidation-resistant metal such as stainless steel.
- the tube material 2 ′ undergoes a specific rolling process in order to form the continuous spiral fin 22 integral with the periphery of the tube 21 .
- the tube material 2 ′ before the rolling process is approximately 10 mm in outer diameter, approximately 7 mm in inner diameter, and approximately 1.5 mm in wall thickness.
- the fin height (Fh) and the fin thickness (Ft) are determined so as to achieve a target heat exchange performance and a target exhaust flow performance (exhaust flow pressure loss).
- the wall thickness of a part of the peripheral portion of the tube material 2 ′, which is used as a fin forming portion, is set smaller than the thickness (t) of the tube 21 (or smaller than a half of the wall thickness of the tube material 2 ′), for example, approximately 0.7 mm, to provide a thin and high fin shape.
- the fin forming portion is plastic-deformed in the radial direction such that the fin height is between 1.8 mm and 2.6 mm to achieve the target performances.
- a common rolling process is for plastic-deforming a row material to the shape analogous to the shape of the outer surface of a rolling roller by pressing the rolling roller to the periphery of the row material. Accordingly, common rolling rollers are not suitable for shaping the thin-wall tube material 2 ′ to have a thin-wall fin by deforming the tube material 2 ′ to expand radially outward.
- a newly developed rolling roller head 4 specialized for use in fin forming is used in this embodiment.
- a manufacturing apparatus including the rolling roller head 4 and a method of manufacturing the fin-integrated tube using this manufacturing apparatus are explained in the following.
- the manufacturing apparatus for manufacturing the fin-integrated tube 2 has a processing bench 7 on which a tube holding part 3 for holding and fixing the tube material 2 ′ to be processed and the for rolling part 6 including a rolling roller head 4 of three-roller type and a rolling head holder 5 are mounted so as to be opposed to each other.
- the tube holding part 3 includes a holding chuck 31 for holding the proximal end portion (the left end portion in FIG. 3 ) of the material tube 2 ′.
- the holding chuck 31 is mounted to a rotating shaft 32 coupled to a driving part 72 .
- the tube material 2 ′ can be rotated by rotating the rotating shaft 32 .
- the form rolling part 6 is axially movable on the processing bench 7 by a conveying shaft 61 mounted on a supporting table 62 supporting the rolling head holder 5 to which the roller head 4 is mounted.
- the driving part 71 drives the conveying shaft 61 in synchronism with the rotating shaft 32 to move the rolling roller head 4 toward the end portion (the right end portion in FIG. 1 ) of the tube material 2 ′ disposed coaxially with the rolling roller head 4 at a predetermined speed.
- the rolling roller head 4 includes a flange portion 44 to which the roller group (the rollers 41 , 42 and 43 ) is mounted and a cylindrical proximal end portion 45 .
- the cylindrical proximal end portion 45 of the rolling roller head 4 is inserted and fixed to a movable sleeve 52 having a container-like shape.
- the movable sleeve 52 is axially and slidably supported in a slide hole 51 formed so as to open to one end (the left side end in FIG. 3 ) of the head holder 5 .
- the rolling head holder 5 includes an axially elongated hole 55 penetrating through the lateral wall of the slide hole 51 .
- the movable sleeve 52 includes locking pins 54 formed in the periphery thereof so as to project from the elongated hole 55 to restrict the movable sleeve 52 from moving in the rotating direction.
- a coil-shaped compression spring 56 is disposed as a biasing member to bias the movable sleeve 52 toward the rolling roller head 4 .
- the movable sleeve 52 and the spring 56 constitute an extension absorbing mechanism for absorbing extension of the tube material 2 ′ being form-rolled.
- the movable sleeve 52 can move to a distance adaptable to extension of the tube material 2 ′.
- the spring 56 is disposed in the rear of the movable sleeve 52 (opposite the rolling roller head 4 ) and always biased forward (toward the tube forming direction) at an appropriate load.
- the biasing force applied to the movable sleeve 52 can be determined through pretest to such a value that generates a pressing force enabling the roller crests of the rolling rollers 41 , 42 and 43 to bite the periphery of the tube material 2 ′ at the beginning of a forming process and to retract to absorb extension of the tube material 2 ′.
- An adjustment screw 57 is mounted to the opening formed in the other end (the right side end in FIG. 3 ) of the rolling head holder 5 . By screwing in the adjustment screw 57 in the axial direction, the compression amount of the spring 56 to which the adjustment screw 57 abuts can be adjusted.
- the rolling roller head 4 includes, as a rolling roller group surrounding the periphery of the tube material 2 ′ in three directions, the three rolling rollers 41 , 42 and 43 disposed in a concentric pattern at even intervals.
- Each of the rolling rollers 41 , 42 and 43 includes a plurality of the roller crests 44 at its periphery to form a desired fin shape.
- the rolling rollers 41 , 42 and 43 are rotatably supported by the rolling roller head 4 such that they are inclined by a predetermined lead angle (three degrees in this embodiment) to the center axis of the tube material 2 ′.
- the roller crests 44 are formed of concavo-convex portions arranged in the axial direction at even pitch.
- the three rolling rollers 41 , 42 and 43 are displaced by a predetermined pitch from one another in the axial direction. Accordingly, by sending the rolling roller head 4 in synchronism with rotation of the tube material 2 ′ (one pitch per one rotation), the tube material 2 ′ is pushed in between the rolling rollers 41 , 42 and 43 , and the rolling rollers 41 , 42 and 43 move relative to the tube material 2 ′ in the axial direction while being driven to rotate. As a result, the roller crests 44 of the rolling rollers 41 , 42 and 43 move past the periphery of the tube material 2 ′ in succession while pressing the periphery to form the fin 22 projecting spirally.
- this embodiment uses the three rolling rollers 41 , 42 and 43 as a gradual roller whose roller crests 44 change in shape stepwise along the axial direction. More specifically, as shown in FIG. 9 , the end portions of the roller crests 44 of each of the rolling rollers 41 , 42 and 43 are rounded so as to be R-shaped portions having a circular arch shape (referred to as the “R-shaped end portions” hereinafter), the sizes (widths) of the R-shaped end portions becoming gradually larger from one axial end to the other axial end.
- the roller crest 44 at the one axial end has a roughly triangular-cross section as a whole and is formed to a shape of sufficiently small “R” at its end, so that it can bite the tube material 2 ′ easily.
- the arc diameters of the R-shaped end portions are gradually increased along the axial direction, and accordingly, the roller crests 44 near the other axial end (near the rolling head holder 5 ) have an inverted U-shaped cross-section as a whole.
- the tube material 2 ′ is not deformed easily because the rolling roller head 4 applies load in three directions.
- the three rolling rollers 41 , 42 and 43 serve as a gradual roller, the processing load can be reduced.
- the roller crests 44 of the rolling roller group constituted of the three rolling rollers 41 , 42 and 43 are shaped such that the R-shaped end portions become gradually larger in the time order of abutment on the tube material 2 ′. Some of the adjacent R-shaped end portions may be the same in shape, if the arc diameters (R) of the R-shaped end portions of the roller crests 44 increase stepwise in the axial direction as a whole.
- the R-shaped end portions of the roller crests 44 of the rolling rollers 41 , 42 and 43 are different from one another in shape except those at their both ends.
- the arc diameter R at the 2nd row is a mm for the rolling roller 41 , a+0.02 mm for the rolling roller 42 , and a+0.04 mm for the rolling roller 43 .
- the arc diameter R is increased with the increase of the row number for all of the rolling rollers 41 , 42 and 43 .
- the arc diameter R at the 11th row is 6a-0.05 mm for the rolling roller 41 , 6a-0.03 mm for the rolling roller 42 , and 6a-0.01 mm for the rolling roller 43 .
- FIGS. 10 and 11 are schematic diagrams for explaining the fin shaping process using the rolling rollers 41 , 42 and 43 as a gradually R-changing roller.
- the fin forming portion of thickness of t of the periphery of the tube material 2 ′ is pushed into the shape analogous to the roller crests 44 at a small load.
- the R-shaped end portions of the roller crests 44 pushing into the periphery of the tube material 2 ′ are gradually increased in size, as a result of which the tube material 2 ′ is squeezed between the lateral sides of the roller crests 44 to be plastic-deformed so as to extend upward.
- the fin shaping process can be smoothly performed by squeezing up the fin forming portion so as to change from a roughly trapezoidal shape to a desired fin shape using the roller crests.
- the root portions between adjacent roller crests are shaped such that they become gradually deeper in the direction from the end at which the R-shaped end portion is minimum to the end at which the R-shaped end portion is maximum.
- the fin height is gradually increased. Accordingly, the depth of the root portion at the end at which the R-shaped end portion is minimum can be made sufficiently small to prevent the rolling rollers 41 , 42 and 43 from being broken, because it is only required to hold the fin 22 at this end.
- the root portions are shaped such that their depths gradually increase with the progress of the fin shaping process so as to provide necessary spaces for holding the fin being formed to project radially outward.
- the roller angle (the angle theta formed by the lateral sides of adjacent roller crests 44 ) is V-shaped when their R-shaped end portions are small, and becomes gradually narrower as the R-shaped end portions become larger. Accordingly, the pushing force is dispersed to the lateral sides to facilitate the fin shaping.
- the roller crests 44 are rounded at their ends, and the widths of their ends are gradually increased (as roller crests of a totally gradually R-changing roller).
- extension toward the chuck 31 occurs in the tube material 2 ′ when the leading roller crest 44 (the first crest in FIG. 14 ) of each of the rolling rollers 41 , 42 and 43 bites the periphery of the tube material 2 ′. Since this extension is accumulated for each of the roller crests biting the periphery of the tube material 2 ′, the tube material 2 ′ is likely to be axially compressed and deformed.
- the rolling head holder 5 shown in FIG. 15 is configured such that the proximal end portion 45 of the rolling roller head 4 is resiliently supported by the movable sleeve 52 and the spring 56 so as to be movable relative to the rolling head holder 5 . Accordingly, the rolling head holder 5 shown in FIG. 15 can release the tube extension stress occurring between the tube material 2 ′ rotating pivoted at one end thereof and the rolling roller head 4 advancing forward at a constant speed by receiving the tube extension stress in the movable sleeve 52 and retracting the spring 56 while compressing it. Hence, according to the rolling head holder 5 shown in FIG. 15 , it is possible to prevent the tube material 2 ′ from being deformed by absorbing the extension of the tube material 2 ′.
- FIG. 16 is a side view showing an example of the shape of the roller crests of a modification of the rolling roller head 4 included in a manufacturing apparatus according to a second embodiment of the invention.
- FIG. 17 is a schematic diagram for explaining a tube forming process performed using the modification of the rolling roller head 4 .
- each of the rolling rollers 41 , 42 and 43 is constituted of a first rolling roller 4 a and a second rolling roller 4 b to enable performing a two-stage rolling.
- the first rolling roller 4 a which is a main part of the rolling roller head 4 , is a gradually R-changing roller whose R-shaped end portions of the roller crests 44 become larger gradually as is the case of the first embodiment.
- the R-shaped end portions are smaller at the forward end of the tube material 2 ′ and larger at the rearward end of the tube material 2 ′ so that the fin forming portion is squeezed radially outward (upward in FIG. 17 ) gradually (Ft1).
- the heights (outer diameters D1) of the roller crests 44 are the same, while the depths of the root portions between adjacent roller crests 44 become gradually larger so that the fin forming portion which becomes gradually higher with the progress of the fin shaping process can be held in the root portions securely.
- the second rolling roller 4 b disposed following the first rolling roller 4 a is a projecting roller configured such that the heights (outer diameters D2) of the roller crests 44 are higher than those of the first rolling roller 4 a , and become gradually larger toward the rear end thereof.
- the fin height can be more increased. Since the tube material 2 ′ has been made thin by the first rolling roller 4 a , the plastic deformation by the second rolling roller 4 b can be facilitated.
- FIG. 18 is a schematic diagram for explaining a method of manufacturing a fin-integrated tube performed using a cored bar as a third embodiment of the invention.
- FIG. 18 there is slight plastic deformation in the inner wall of the formed tube 21 in the direction in which it was pushed by the rolling rollers 41 , 42 and 43 .
- Such plastic deformation can be reduced by performing the forming process using a cored bar 8 mounted to the inner wall of the tube 21 .
- Using the cored bar 8 facilitates the roller crests 44 to bite the tube 21 , and minimizes escape of the tube 21 caused by resilient deformation of the tube 21 at the time of pushing the roller crests 44 into the tube 21 , to thereby maximize the height of the fin 22 . Further, using the cored bar 8 reinforces the thin tube 21 and makes it resistant to bending.
- the fin-integrated tube 2 of the invention underwent a heat endurance test in a state of being mounted to the exhaust heat recovery device shown in FIGS. 6 and 7 . More specifically, the exhaust heat recovery device was fabricated by disposing a plurality of the fin-integrated tubes 2 inside the duct D to constitute the heating section 1 , and the temperature of the gas flowing into the duct D was changed repeatedly (2,000 cycles) within the range from 100 to 900° C. For comparison, the same test was performed for the conventional fin-integrated tube shown in FIG. 19 .
- the fin 22 of the fin-integrated tube 2 of the invention did not change in shape before and after the test. Further, the heat exchange performance and the pressure loss were found to be within a predetermined standard. On the other hand, in the case of the conventional fin-integrated tube, the fin deformation gradually increased with the increase of the cycles due to difference in linear expansion coefficient in the dissimilar metal joint thereof. After 2,000 cycles of the change of the gas temperature, the heat exchange performance dropped by 25%, and the pressure loss dropped by 50%. From this test, it was confirmed that the fin-integrated tube 2 of the present invention exhibits high durability under high temperature environment.
- the manufacturing method of the present invention enables manufacturing fin-integrated tubes integrally provided with a spiral fin with a high degree of formability by using the three-roller type rolling roller head including gradual rollers. According to the manufacturing method of the present invention, since the tube material 2 ′ is plastic-deformed, the material is not wasted unlike in conventional machining or cutting work, and it is easy to adjust the heat transfer area (heat exchange performance) of the fin by adjusting the fin pitch depending on the lead angle of the rolling roller.
- stainless steel is used as the material of the fin-integrated tube 2 .
- a metal material having good heat conductivity such as aluminum or copper, or an alloy of them may be used depending on the usage environment.
- the material of the rolling rollers 41 , 42 and 43 can be determined depending on the material of the tube material 2 ′. For example, when the tube material 2 ′ is made of a hard material, the rolling rollers 41 , 42 and 43 may be made of a stronger material such as an ultrahard alloy.
- the fin-integrated tube manufactured by the manufacturing method or apparatus of the present invention can be used for various heat exchangers other than exhaust heat recover devices, such as those used in a cooling system, a driving system or an air-conditioning system of a vehicle.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
- Shaping Metal By Deep-Drawing, Or The Like (AREA)
- Exhaust Silencers (AREA)
Abstract
The method of manufacturing a fin-integrated tube for a heat exchanger includes step of disposing a rolling roller group including rolling rollers so as to surround the periphery of a tube, each of the roller crests of the rolling rollers being rounded at an end thereof into an R-shape, widths of the R-shaped ends being gradually increased from one axial end to the other axial end for each of the rolling rollers, and step of causing the roller crests to press the periphery of the tube from the one axial end to the other axial end by axially moving and rotating the rolling roller group relative to the tube so as to deform a part of the periphery of the tube into a spirally projecting portion while shaping it into a spiral fin by gradually squeezing the part of the periphery of the tube using the R-shaped end portions.
Description
- This application claims priority to Japanese Patent Application No. 2013-18326 filed on Feb. 1, 2013, the entire contents of which are hereby incorporated by reference.
- 1. Field of the Invention
- The present invention relates to a method and an apparatus for manufacturing a high temperature-resistant fin-integrated tube for use in a heat-exchanger mountable on a vehicle.
- 2. Description of Related Art
- There are known various heat exchangers which can be used in a cooling system, a driving system and an air-conditioning system of a vehicle.
FIG. 19 shows a common fin-integrated tube for use in a heat exchanger. This fin-integrated tube includes atube 200 through which heat-exchanging medium flows and a plurality of hat-shaped rings 201 brazed to thetube 200 such that thetube 200 passes through a stack of the hat-shaped rings 201 asfins 202. - It is known to form a plurality of fins integrally with a tube serving as a radiator to provide a compact and highly-efficient heat exchanger. For example, refer to Japanese Patent Application Laid-open No. 2001-332666. This patent document describes carving the outer or inner wall of a tube to form a plurality of fins which are integrally connected to the tube at their thick proximal end portions. The plurality of the fins are formed using a carving knife such that they become thinner from their proximal end portions to their distal end portions to increase their surface area to thereby increase the heat dissipation effect.
- As a heat exchanger mountable on a vehicle, the exhaust heat recovery device is receiving attention. The exhaust heat recovery device recovers exhaust heat emitted from an engine. The exhaust heat recovery device includes a fin-integrated tube which contains pure water and is mounted in the exhaust passage of the engine for recovering the exhaust heat. Since this fin-integrated tube is exposed to exhaust gas, it is made of heat-resistant and corrosion-resistant stainless steel and their fins are joined to the tube using a nickel-based brazing material, for example.
- However, it turned out that the fins of such a fin-integrated tube may be deformed due to a linear expansion difference in the dissimilar metal joint by the brazing material in a case of a high-efficiency engine that emits high-temperature exhaust gas (900° C., for example). Further, if the number of the fins is increased to increase the heat exchange efficiency, manufacturing time and cost increase greatly because the fins have to be joined one by one to the tube.
- The inventors of the present invention studied a possibility of adoption of a fin-integrated tube which does not include any brazing material, and can be manufactured by the method described in the above patent document. However, the method of carving the tube surface to form fins as described in the above patent document, which is suitable for the case where the tube is made of metal easy to carve such as aluminum, is difficult to use in the case where the tube is made of stainless steel. Further, the wall thickness and the rigidity of the tube have to be sufficiently large, while on the other hand, the shapes of the fins formed by carving the outer or inner surface of the tube along its axis and the wall thickness after the carving of the tube are likely to be non-uniform. Hence, it is difficult to reduce individual difference in the radiation performance. As explained above, it has been difficult so far to achieve both reducing the manufacturing cost and increasing the heat exchange efficiency.
- An exemplary embodiment provides a method of manufacturing a fin-integrated tube for a heat exchanger, the fin-integrated tube including a cylindrical tube and a spiral fin integrally formed in a periphery of the tube, including the steps of:
- disposing a rolling roller group including a plurality of rolling rollers each having a plurality of roller crests on a periphery thereof so as to surround the periphery of the tube with a predetermined lead angle, each of the roller crests being rounded at an end thereof into an R-shape to be an R-shaped end, widths of the R-shaped ends of the roller crests being gradually increased from one axial end to the other axial end for each of the rolling rollers, so that each of the rolling rollers serves as a gradual roller; and
- causing the roller crests of the rolling rollers to press the periphery of the tube from the one axial end to the other axial end by axially moving and rotating the rolling roller group relative to the tube so as to deform a part of the periphery of the tube into a spirally projecting portion while shaping the spirally projecting portion into the spiral fin by gradually squeezing the part of the periphery of the tube using the R-shaped end portions of the roller crests of the rolling rollers.
- The exemplary embodiment provides also a manufacturing apparatus for manufacturing a fin-integrated tube for a heat exchanger, the fin-integrated tube including a cylindrical tube and a spiral fin integrally formed in a periphery of the tube, including:
- a tube holding part for holding a proximal end portion of the tube so as to be rotatable together with the tube; and
- a rolling roller head disposed coaxially with the tube so as to be axially movable relative to the tube;
- the rolling roller head having a rolling roller group including a plurality of rolling rollers each having a plurality of roller crests on a periphery thereof, said rolling roller group being configured to surround the periphery of the tube with a predetermined lead angle,
- each of the roller crests being rounded at an end thereof into an R-shape to be an R-shaped end, widths of the R-shaped ends of the roller crests being gradually increased from one axial end to the other axial end for each of the rolling rollers, so that each of the rolling rollers serves as a gradual roller,
- wherein
- the rolling roller head is configured to be driven to axially move in a direction from a distal end to a proximal end of the tube and rotate relative to the tube so as to cause the roller crests of the rolling rollers to press the periphery of the tube in the direction from the distal end to the proximal end so as to deform a part of the periphery of the tube into a spirally projecting portion while shaping the spirally projecting portion into the spiral fin by gradually squeezing the part of the periphery of the tube using the R-shaped end portions of the roller crests of the rolling rollers.
- According to the exemplary embodiment, there is provided a high-performance and low-cost heat exchanger for vehicle use, which includes fin-integrate tubes manufactured without use of brazing material.
- Other advantages and features of the invention will become apparent from the following description including the drawings and claims.
- In the accompanying drawings:
-
FIG. 1 is a general view of a manufacturing apparatus for manufacturing a fin-integrated tube according to a first embodiment of the invention; -
FIG. 2 is a partially enlarged view of the fin-integrated tube manufactured by a method performed using the manufacturing apparatus according to the first embodiment of the invention; -
FIG. 3 is a partially enlarged view of a form rolling part of the manufacturing apparatus according to the first embodiment of the invention; -
FIG. 4 is plan and side views of a form rolling roller head constituting the rolling part; -
FIG. 5 is a partially enlarged view of an exhaust heat recovery device including the fin-integrated tubes manufactured by the method performed using the manufacturing apparatus according to the first embodiment of the invention; -
FIG. 6 is a cross-sectional view of the exhaust heat recovery device; -
FIG. 7 is a perspective view of the exhaust heat recovery device; -
FIG. 8 is a schematic diagram for explaining a rolling process performed using the rolling roller head of the rolling part of the manufacturing apparatus according to the first embodiment of the invention; -
FIG. 9 is a diagram showing an example of the shapes of the roller crests of rolling rollers of the rolling roller head; -
FIGS. 10 and 11 are schematic diagrams for explaining a fin shaping process performed using the rolling rollers; -
FIG. 12 is a schematic diagram for explaining variation of effect of the rolling rollers depending on variation of the angles of the roller crests of the rolling rollers; -
FIG. 13 is a schematic diagram for explaining variation of the effect of the rolling rollers depending on variation of the R-shaped end portions of the roller crests of the rolling rollers; -
FIG. 14 is a schematic diagram for explaining a tube extension at the time of the rolling process; -
FIG. 15 is a cross-sectional view for explaining effects of a extension absorbing mechanism of the rolling roller head; -
FIG. 16 is a side view showing an example of the shapes of the roller crests of rolling rollers of a manufacturing apparatus according to a second embodiment of the invention; -
FIG. 17 is a schematic diagram for explaining a tube forming process performed using the rolling rollers of the manufacturing apparatus according to the second embodiment of the invention; -
FIG. 18 is a schematic diagram for explaining a method of manufacturing a fin-integrated tube performed using a cored bar as a third embodiment of the invention; and -
FIG. 19 is a perspective view of a conventional fin-integrated tube. -
FIG. 1 is a general view of a manufacturing apparatus according to a first embodiment of the invention, which manufactures a fin-integratedtube 2 shown inFIG. 2 . The fin-integratedtube 2 is used for various vehicle-mounted heat exchangers. The fin-integratedtube 2 is made from acylindrical tube material 2′. Thetube material 2′ is plastic-deformed by arolling roller head 4 of aform rolling part 6 to form the fin-integratedtube 2 including atube 21 and a fin 22 wound spirally on the outer periphery of thetube 21 at a predetermined pitch.FIG. 3 is a partially enlarged view of theform rolling part 6 which is a main part of the manufacturing apparatus.FIG. 4 is plan and side views of therolling roller head 4 of theform rolling part 6. -
FIG. 5 is a partially enlarged view of an exhaust heat recovery device including the fin-integratedtubes 2.FIG. 6 is a cross-sectional view of the exhaust heat recovery device.FIG. 7 is a perspective view of the exhaust heat recovery device. The heat recovery device is for recovering exhaust heat emitted from an engine, and exchanging heat with engine cooling water. The exhaust heat recovery device is used for warming the engine to increase fuel economy. As shown inFIGS. 6 and 7 , the exhaust heat recovery device includes a heating section (heat exchanging section) 1 housing a plurality of the fin-integratedtubes 2, aheat guard 100 above which a tank is disposed, and acondensing section 101 having a LCC pipe P through which the engine cooling water (LLC) flows. Theheating section 1 is mounted inside a duct D provided midway of the exhaust passage of the engine. The condensingsection 101 is disposed in the upper space of the tank. Theheating section 1 and thecondensing section 101 are loop-connected to each other through asteam passage 102 and avalve 103 to constitute a loop heat pipe (heat loop) enclosing working medium. The loop heat pipe operates to transfer heat by evaporation and condensation of the working medium. In this embodiment, pure water is used as the working medium. - The
heating section 1 includes a plurality of the fin-integratedtubes 2 which are arranged in rows along the flow direction of the exhaust gas and in rows along the direction perpendicular to the flow direction of the exhaust gas within the duct D. Each of the fin-integratedtubes 2 includes thetube 21 extending in the direction perpendicular to the flow direction of the exhaust gas and thespiral fin 22 projecting radially outward from the periphery of thetube 21. The bottom end of thetube 21 is closed, and the top end of thetube 21 penetrates through acore plate 3 forming the bottom plate of the tank and opens to the lower space in the tank. The inside of the tank is partitioned into the upper space and the lower space by atank inner 4. Thetank inner 4 is formed with thesteam passage 102 projecting upward. The lower space to which the fin-integratedtubes 2 open and the upper space in which thecondensing section 101 is disposed are in communication through thesteam passage 102. - The steam introduced from the
steam passage 102 into thecondensing section 101 exchanges heat with the engine cooling water by contacting with the LLC pipe, and becomes condensed water. The condensed water is refluxed back to theheating section 1 by opening or closing thevalve 103 depending on the pressure inside the tank. Apartition 105 having anoxygen introducing hole 104 is provided in the lateral direction of thesteam passage 102 for removing oxygen generated by contact between high-temperature steam and metal, for example. A copperoxide containing case 106 containinggranular copper oxide 107 is provided below the space partitioned by thepartition 105. The generated hydrogen is guided from thehydrogen introducing hole 104 to the copperoxide containing case 106, and reduced to be removed. - As shown in
FIG. 5 , thefin 22 is integrally connected to thetube 21 at its proximal end portion, and exchanges heat with the exhaust gas contacting the fin surface at its thin distal end portion which is spirally joined to thetube 21 in layers at a predetermined fin pitch (Fp) in the axial direction of thetube 21. The fin-integratedtube 2 is exposed to high-temperature exhaust gas in the duct D. Accordingly, the fin-integratedtube 2 is made of a heat-resistant and oxidation-resistant metal such as stainless steel. As described in the foregoing, conventional fin-integrated tubes manufactured by brazing have a concern that their fins may be deformed in a usage environment where the temperature of exhaust gas is high (100 to 900° C., for example) causing the heat exchange efficiency to be lowered. - Hence, in this embodiment, the
tube material 2′ undergoes a specific rolling process in order to form thecontinuous spiral fin 22 integral with the periphery of thetube 21. Thetube material 2′ before the rolling process is approximately 10 mm in outer diameter, approximately 7 mm in inner diameter, and approximately 1.5 mm in wall thickness. The fin height (Fh) and the fin thickness (Ft) are determined so as to achieve a target heat exchange performance and a target exhaust flow performance (exhaust flow pressure loss). The wall thickness of a part of the peripheral portion of thetube material 2′, which is used as a fin forming portion, is set smaller than the thickness (t) of the tube 21 (or smaller than a half of the wall thickness of thetube material 2′), for example, approximately 0.7 mm, to provide a thin and high fin shape. For example, when the fin pitch is 1.5 mm, the fin forming portion is plastic-deformed in the radial direction such that the fin height is between 1.8 mm and 2.6 mm to achieve the target performances. - Generally, a common rolling process is for plastic-deforming a row material to the shape analogous to the shape of the outer surface of a rolling roller by pressing the rolling roller to the periphery of the row material. Accordingly, common rolling rollers are not suitable for shaping the thin-
wall tube material 2′ to have a thin-wall fin by deforming thetube material 2′ to expand radially outward. Hence, a newly developed rollingroller head 4 specialized for use in fin forming is used in this embodiment. A manufacturing apparatus including the rollingroller head 4, and a method of manufacturing the fin-integrated tube using this manufacturing apparatus are explained in the following. - As shown in
FIG. 1 , the manufacturing apparatus for manufacturing the fin-integratedtube 2 has aprocessing bench 7 on which atube holding part 3 for holding and fixing thetube material 2′ to be processed and the for rollingpart 6 including a rollingroller head 4 of three-roller type and a rollinghead holder 5 are mounted so as to be opposed to each other. Thetube holding part 3 includes a holdingchuck 31 for holding the proximal end portion (the left end portion inFIG. 3 ) of thematerial tube 2′. The holdingchuck 31 is mounted to arotating shaft 32 coupled to a driving part 72. Thetube material 2′ can be rotated by rotating therotating shaft 32. Theform rolling part 6 is axially movable on theprocessing bench 7 by a conveyingshaft 61 mounted on a supporting table 62 supporting the rollinghead holder 5 to which theroller head 4 is mounted. The drivingpart 71 drives the conveyingshaft 61 in synchronism with the rotatingshaft 32 to move the rollingroller head 4 toward the end portion (the right end portion inFIG. 1 ) of thetube material 2′ disposed coaxially with the rollingroller head 4 at a predetermined speed. - As shown in
FIG. 3 , the rollingroller head 4 includes aflange portion 44 to which the roller group (therollers proximal end portion 45. The cylindricalproximal end portion 45 of the rollingroller head 4 is inserted and fixed to amovable sleeve 52 having a container-like shape. Themovable sleeve 52 is axially and slidably supported in aslide hole 51 formed so as to open to one end (the left side end inFIG. 3 ) of thehead holder 5. The rollinghead holder 5 includes an axiallyelongated hole 55 penetrating through the lateral wall of theslide hole 51. Themovable sleeve 52 includes locking pins 54 formed in the periphery thereof so as to project from theelongated hole 55 to restrict themovable sleeve 52 from moving in the rotating direction. Between the bottom of themovable sleeve 52 and the other end (the right side end inFIG. 3 ) of the rollinghead holder 5, a coil-shapedcompression spring 56 is disposed as a biasing member to bias themovable sleeve 52 toward the rollingroller head 4. - The
movable sleeve 52 and thespring 56 constitute an extension absorbing mechanism for absorbing extension of thetube material 2′ being form-rolled. Themovable sleeve 52 can move to a distance adaptable to extension of thetube material 2′. Thespring 56 is disposed in the rear of the movable sleeve 52 (opposite the rolling roller head 4) and always biased forward (toward the tube forming direction) at an appropriate load. The biasing force applied to themovable sleeve 52 can be determined through pretest to such a value that generates a pressing force enabling the roller crests of the rollingrollers tube material 2′ at the beginning of a forming process and to retract to absorb extension of thetube material 2′. Anadjustment screw 57 is mounted to the opening formed in the other end (the right side end inFIG. 3 ) of the rollinghead holder 5. By screwing in theadjustment screw 57 in the axial direction, the compression amount of thespring 56 to which theadjustment screw 57 abuts can be adjusted. - As shown in
FIG. 4 , the rollingroller head 4 includes, as a rolling roller group surrounding the periphery of thetube material 2′ in three directions, the three rollingrollers rollers rollers roller head 4 such that they are inclined by a predetermined lead angle (three degrees in this embodiment) to the center axis of thetube material 2′. - As shown in
FIG. 8 , the roller crests 44 are formed of concavo-convex portions arranged in the axial direction at even pitch. The three rollingrollers roller head 4 in synchronism with rotation of thetube material 2′ (one pitch per one rotation), thetube material 2′ is pushed in between the rollingrollers rollers tube material 2′ in the axial direction while being driven to rotate. As a result, the roller crests 44 of the rollingrollers tube material 2′ in succession while pressing the periphery to form thefin 22 projecting spirally. - It is not easy to form such a fin shape which is thin and has a large heat transfer area. Hence, this embodiment uses the three rolling
rollers FIG. 9 , the end portions of the roller crests 44 of each of the rollingrollers roller crest 44 at the one axial end has a roughly triangular-cross section as a whole and is formed to a shape of sufficiently small “R” at its end, so that it can bite thetube material 2′ easily. The arc diameters of the R-shaped end portions are gradually increased along the axial direction, and accordingly, the roller crests 44 near the other axial end (near the rolling head holder 5) have an inverted U-shaped cross-section as a whole. - The
tube material 2′ is not deformed easily because the rollingroller head 4 applies load in three directions. In addition, since the three rollingrollers rollers tube material 2′. Some of the adjacent R-shaped end portions may be the same in shape, if the arc diameters (R) of the R-shaped end portions of the roller crests 44 increase stepwise in the axial direction as a whole. - Preferably, the R-shaped end portions of the roller crests 44 of the rolling
rollers FIG. 9 shows an example of this case, where each of the rollingrollers rollers rollers roller 41, a+0.02 mm for the rollingroller 42, and a+0.04 mm for the rollingroller 43. For the 3rd to 10th rows, the arc diameter R is increased with the increase of the row number for all of the rollingrollers roller roller roller 43. It is possible to disperse the processing load to thereby form the fin shape with high precision by differentiating the roller crests 44 in shape, and to reduce variation of the formed fin shape by equating the shapes of the roller crests 44 of the rollingrollers -
FIGS. 10 and 11 are schematic diagrams for explaining the fin shaping process using the rollingrollers tube material 2′ is pushed into the shape analogous to the roller crests 44 at a small load. Thereafter, the R-shaped end portions of the roller crests 44 pushing into the periphery of thetube material 2′ are gradually increased in size, as a result of which thetube material 2′ is squeezed between the lateral sides of the roller crests 44 to be plastic-deformed so as to extend upward. Accordingly, since the pushing force is dispersed to the lateral sides, the fin shaping process can be smoothly performed by squeezing up the fin forming portion so as to change from a roughly trapezoidal shape to a desired fin shape using the roller crests. - As shown in
FIG. 10 , the root portions between adjacent roller crests are shaped such that they become gradually deeper in the direction from the end at which the R-shaped end portion is minimum to the end at which the R-shaped end portion is maximum. As shown inFIG. 11 , the fin height is gradually increased. Accordingly, the depth of the root portion at the end at which the R-shaped end portion is minimum can be made sufficiently small to prevent the rollingrollers fin 22 at this end. The root portions are shaped such that their depths gradually increase with the progress of the fin shaping process so as to provide necessary spaces for holding the fin being formed to project radially outward. - Next, the advantages of using the roller crests of the rolling
rollers FIGS. 12 and 13 . As shown inFIG. 12 , the roller angle (the angle theta formed by the lateral sides of adjacent roller crests 44) is V-shaped when their R-shaped end portions are small, and becomes gradually narrower as the R-shaped end portions become larger. Accordingly, the pushing force is dispersed to the lateral sides to facilitate the fin shaping. As shown inFIG. 13 , the roller crests 44 are rounded at their ends, and the widths of their ends are gradually increased (as roller crests of a totally gradually R-changing roller). Accordingly, it is possible to prevent a shearing stress from concentrating in their ends and to disperse the shearing stress to the lateral sides. Further, since the arc diameters (R) are gradually increased, most of the portion being shaped by the following roller is limited in the area facing a 45-degree lateral sector of the circumference of the leading roller. This makes it possible to extend the fin forming portion upward by a large amount, because the forming load can be sufficiently dispersed to the lateral sides while squeezing the thick wall portion at the fin proximal end portion. - Next, effects of the extension absorbing mechanism provided in the rolling
head holder 5 are explained with reference toFIGS. 14 and 15 . In this embodiment, as shown inFIG. 14 , extension toward thechuck 31 occurs in thetube material 2′ when the leading roller crest 44 (the first crest inFIG. 14 ) of each of the rollingrollers tube material 2′. Since this extension is accumulated for each of the roller crests biting the periphery of thetube material 2′, thetube material 2′ is likely to be axially compressed and deformed. On the other hand, the rollinghead holder 5 shown inFIG. 15 is configured such that theproximal end portion 45 of the rollingroller head 4 is resiliently supported by themovable sleeve 52 and thespring 56 so as to be movable relative to the rollinghead holder 5. Accordingly, the rollinghead holder 5 shown inFIG. 15 can release the tube extension stress occurring between thetube material 2′ rotating pivoted at one end thereof and the rollingroller head 4 advancing forward at a constant speed by receiving the tube extension stress in themovable sleeve 52 and retracting thespring 56 while compressing it. Hence, according to the rollinghead holder 5 shown inFIG. 15 , it is possible to prevent thetube material 2′ from being deformed by absorbing the extension of thetube material 2′. -
FIG. 16 is a side view showing an example of the shape of the roller crests of a modification of the rollingroller head 4 included in a manufacturing apparatus according to a second embodiment of the invention.FIG. 17 is a schematic diagram for explaining a tube forming process performed using the modification of the rollingroller head 4. In the second embodiment, as shown inFIG. 16 , each of the rollingrollers first rolling roller 4 a and asecond rolling roller 4 b to enable performing a two-stage rolling. Thefirst rolling roller 4 a, which is a main part of the rollingroller head 4, is a gradually R-changing roller whose R-shaped end portions of the roller crests 44 become larger gradually as is the case of the first embodiment. That is, as shown inFIG. 17 , the R-shaped end portions are smaller at the forward end of thetube material 2′ and larger at the rearward end of thetube material 2′ so that the fin forming portion is squeezed radially outward (upward inFIG. 17 ) gradually (Ft1). In thefirst rolling roller 4 a, the heights (outer diameters D1) of the roller crests 44 are the same, while the depths of the root portions between adjacent roller crests 44 become gradually larger so that the fin forming portion which becomes gradually higher with the progress of the fin shaping process can be held in the root portions securely. - In
FIG. 16 , thesecond rolling roller 4 b disposed following thefirst rolling roller 4 a is a projecting roller configured such that the heights (outer diameters D2) of the roller crests 44 are higher than those of thefirst rolling roller 4 a, and become gradually larger toward the rear end thereof. As shown inFIG. 17 , since thetube material 2′ is gradually pushed radially inward (Fh2: downward inFIG. 17 ), the fin height can be more increased. Since thetube material 2′ has been made thin by thefirst rolling roller 4 a, the plastic deformation by thesecond rolling roller 4 b can be facilitated. - Next, a third embodiment of the invention is described with reference to
FIG. 18 .FIG. 18 is a schematic diagram for explaining a method of manufacturing a fin-integrated tube performed using a cored bar as a third embodiment of the invention. As shown inFIG. 18 , there is slight plastic deformation in the inner wall of the formedtube 21 in the direction in which it was pushed by the rollingrollers bar 8 mounted to the inner wall of thetube 21. Using the coredbar 8 facilitates the roller crests 44 to bite thetube 21, and minimizes escape of thetube 21 caused by resilient deformation of thetube 21 at the time of pushing the roller crests 44 into thetube 21, to thereby maximize the height of thefin 22. Further, using the coredbar 8 reinforces thethin tube 21 and makes it resistant to bending. - The fin-integrated
tube 2 of the invention underwent a heat endurance test in a state of being mounted to the exhaust heat recovery device shown inFIGS. 6 and 7 . More specifically, the exhaust heat recovery device was fabricated by disposing a plurality of the fin-integratedtubes 2 inside the duct D to constitute theheating section 1, and the temperature of the gas flowing into the duct D was changed repeatedly (2,000 cycles) within the range from 100 to 900° C. For comparison, the same test was performed for the conventional fin-integrated tube shown inFIG. 19 . - It was found that the
fin 22 of the fin-integratedtube 2 of the invention did not change in shape before and after the test. Further, the heat exchange performance and the pressure loss were found to be within a predetermined standard. On the other hand, in the case of the conventional fin-integrated tube, the fin deformation gradually increased with the increase of the cycles due to difference in linear expansion coefficient in the dissimilar metal joint thereof. After 2,000 cycles of the change of the gas temperature, the heat exchange performance dropped by 25%, and the pressure loss dropped by 50%. From this test, it was confirmed that the fin-integratedtube 2 of the present invention exhibits high durability under high temperature environment. - The manufacturing method of the present invention enables manufacturing fin-integrated tubes integrally provided with a spiral fin with a high degree of formability by using the three-roller type rolling roller head including gradual rollers. According to the manufacturing method of the present invention, since the
tube material 2′ is plastic-deformed, the material is not wasted unlike in conventional machining or cutting work, and it is easy to adjust the heat transfer area (heat exchange performance) of the fin by adjusting the fin pitch depending on the lead angle of the rolling roller. - In the above embodiments, stainless steel is used as the material of the fin-integrated
tube 2. However, a metal material having good heat conductivity such as aluminum or copper, or an alloy of them may be used depending on the usage environment. The material of the rollingrollers tube material 2′. For example, when thetube material 2′ is made of a hard material, the rollingrollers - The fin-integrated tube manufactured by the manufacturing method or apparatus of the present invention can be used for various heat exchangers other than exhaust heat recover devices, such as those used in a cooling system, a driving system or an air-conditioning system of a vehicle.
- The above explained preferred embodiments are exemplary of the invention of the present application which is described solely by the claims appended below. It should be understood that modifications of the preferred embodiments may be made as would occur to one of skill in the art.
Claims (6)
1. A method of manufacturing a fin-integrated tube for a heat exchanger, the fin-integrated tube including a cylindrical tube and a spiral fin integrally formed in a periphery of the tube, comprising the steps of:
disposing a rolling roller group including a plurality of rolling rollers each having a plurality of roller crests on a periphery thereof so as to surround the periphery of the tube with a predetermined lead angle, each of the roller crests being rounded at an end thereof into an R-shape to be an R-shaped end, widths of the R-shaped ends of the roller crests being gradually increased from one axial end to the other axial end for each of the rolling rollers, so that each of the rolling rollers serves as a gradual roller; and
causing the roller crests of the rolling rollers to press the periphery of the tube from the one axial end to the other axial end by axially moving and rotating the rolling roller group relative to the tube so as to deform a part of the periphery of the tube into a spirally projecting portion while shaping the spirally projecting portion into the spiral fin by gradually squeezing the part of the periphery of the tube using the R-shaped end portions of the roller crests of the rolling rollers.
2. The method of manufacturing a fin-integrated tube for a heat exchanger according to claim 1 , wherein the fin-integrated tube is made of stainless steel.
3. A manufacturing apparatus for manufacturing a fin-integrated tube for a heat exchanger, the fin-integrated tube including a cylindrical tube and a spiral fin integrally formed in a periphery of the tube, comprising:
a tube holding part for holding a proximal end portion of the tube so as to be rotatable together with the tube; and
a rolling roller head disposed coaxially with the tube so as to be axially movable relative to the tube;
the rolling roller head having a rolling roller group including a plurality of rolling rollers each having a plurality of roller crests on a periphery thereof, said rolling roller group being configured to surround the periphery of the tube with a predetermined lead angle,
each of the roller crests being rounded at an end thereof into an R-shape to be an R-shaped end, widths of the R-shaped ends of the roller crests being gradually increased from one axial end to the other axial end for each of the rolling rollers, so that each of the rolling rollers serves as a gradual roller,
wherein
the rolling roller head is configured to be driven to axially move in a direction from a distal end to a proximal end of the tube and rotate relative to the tube so as to cause the roller crests of the rolling rollers to press the periphery of the tube in the direction from the distal end to the proximal end so as to deform a part of the periphery of the tube into a spirally projecting portion while shaping the spirally projecting portion into the spiral fin by gradually squeezing the part of the periphery of the tube using the R-shaped end portions of the roller crests of the rolling rollers.
4. The manufacturing apparatus for manufacturing a fin-integrated tube for a heat exchanger according to claim 3 , wherein heights of the roller crests of each of the rolling rollers increase stepwise in a direction from one axial end to the other axial end thereof.
5. The manufacturing apparatus for manufacturing a fin-integrated tube for a heat exchanger according to claim 3 , further comprising:
a rolling head holder holding the rolling roller head such that the rolling roller head is opposed to the tube holding part on a processing bench, the rolling head holder being formed with a slide hole which opens to an end thereof facing the tube holding part;
a movable sleeve slidably held inside the slide hole and supporting a periphery of a proximal end portion of the rolling roller head; and
a biasing means for biasing the movable sleeve in a direction in which the rolling roller head advances;
the slide hole, the movable sleeve and the biasing means serving as an extension absorbing mechanism for absorbing extension of the tube being form-processed by the manufacturing apparatus.
6. The manufacturing apparatus for manufacturing a fin-integrated tube for a heat exchanger according to claim 3 , wherein the fin-integrated tube is made of stainless steel.
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DE2803274A1 (en) * | 1978-01-26 | 1979-08-02 | Wieland Werke Ag | FIBER TUBE AND THE METHOD AND DEVICE FOR THE PRODUCTION THEREOF |
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JPS6188917A (en) * | 1984-10-09 | 1986-05-07 | Kobe Steel Ltd | Equipment for producing heat transfer tube |
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JPH0994623A (en) * | 1995-09-29 | 1997-04-08 | Sumitomo Metal Ind Ltd | Manufacture of metallic tube with spiral fin |
JPH11277171A (en) * | 1998-03-27 | 1999-10-12 | Nachi Fujikoshi Corp | Method and device for form rolling of gear-shaped object |
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JP4978888B2 (en) * | 2007-05-11 | 2012-07-18 | 日本精工株式会社 | Screw shaft of ball screw mechanism |
-
2013
- 2013-02-01 JP JP2013018326A patent/JP5929773B2/en active Active
- 2013-12-06 US US14/099,303 patent/US20140215825A1/en not_active Abandoned
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US4179911A (en) * | 1977-08-09 | 1979-12-25 | Wieland-Werke Aktiengesellschaft | Y and T-finned tubes and methods and apparatus for their making |
US5365763A (en) * | 1992-05-06 | 1994-11-22 | Escofier Technologie Sa | Device for shaping of helical fins on the outer wall of a tube |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11209225B2 (en) * | 2016-09-29 | 2021-12-28 | Jfe Steel Corporation | Heat exchanger, radiant tube type heating device, and method of manufacturing heat exchanger |
CN114309169A (en) * | 2022-01-06 | 2022-04-12 | 泰州市长征冷机管件有限公司 | Bending processing device for connecting pipe of refrigerator compressor |
CN114515800A (en) * | 2022-01-25 | 2022-05-20 | 曾兰花 | Deformation-preventing fin heating pipe auxiliary production equipment |
CN115815450A (en) * | 2022-12-07 | 2023-03-21 | 无锡化工装备股份有限公司 | Nano-fluid self-lubricating outer surface forming equipment and method for three-dimensional finned circular tube |
Also Published As
Publication number | Publication date |
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JP2014149124A (en) | 2014-08-21 |
JP5929773B2 (en) | 2016-06-08 |
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