JP3186261B2 - Rolling machine with groove for welding heat transfer tube and flat heat transfer tube for welding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grooved rolling device for welding heat transfer tubes used in a pre-welding process in the production of a welded heat transfer tube with inner grooves used for a heat exchanger of an air conditioner, and a device processed by the device. The present invention relates to a flattened heat transfer tube using a strip material.

[0002]

2. Description of the Related Art Compactness of home air conditioners has been promoted in order to make living space comfortable. Advances in compactness are achieved by reducing the overall size of the components.

A large part of an air conditioner has a heat exchange section,
Copper having good thermal conductivity is used for the heat transfer tube through which the heat medium passes, and a groove is formed in the inner surface, for example, in a spiral shape to greatly improve the efficiency.

[0004] In order to manufacture the heat transfer tube with an inner surface groove, a method of manufacturing a seamless copper tube by forming a groove from a billet material through extrusion → rolling → drawing is mainly used.

Recently, in order to make a heat transfer tube with an inner groove thinner,
As shown in FIG. 7, the raw material 1
A method of forming a welded heat transfer tube 13 by subjecting a grooved rolling process to 0 and forming it into a tubular shape by a tubular forming portion 22 and welding the butted portion with an electric resistance welding device 23 is started.

The high-frequency welding method is advantageous as a measure for reducing the size of the heat exchange part because the diameter of the copper tube can be reduced as compared with the seamless manufacturing method.

[0007] Car air conditioners are conventionally provided with heat exchange tubes,
As shown in FIG. 8A, a harmonica tube 25 formed by extrusion of aluminum or a flat tube 27 made of aluminum welded by high frequency as shown in FIG. The attached inner fin tubes 26 are alternately stacked via external fins 29 as shown in FIG.
Nine parts are used for ventilation.

[0008]

SUMMARY OF THE INVENTION Since a heat transfer tube formed by high-frequency welding has a welded portion compared to a seamless tube,
The reliability of this weld needs to be established.

In order to perform welding reliably, the conditions necessary for welding must be satisfied. For this purpose, it is necessary to eliminate conditions that are necessary for welding but may actually deviate from appropriate values.

The main welding conditions are (1) welding temperature ← heat input × speed × thickness × approach angle × resistance, (2) butting ← parallel butting ×
Pressure welding allowance ← board width x thickness x preform x slit shape,
(3) Atmosphere ← no oxidation ← Ar gas flow rate.

[0011] Heat input control is performed by using various fluctuation factors, and the above-mentioned (1) and (3) methods for managing the welding temperature and the welding atmosphere have been established.

[0012] The control method for the butting should be controlled in the steps of strip rolling, slitting, grooving and roll forming, but the method of detecting the fluctuation factors and controlling the processing should be adopted at present. Not. So far, it has relied on inspection and selection of the dimensions of the strip and the slit cross section, and recognizes practical accuracy tolerances (variations) for acceptable products.

The most important factors are the edge edge conditioning and the width of the board and the circular shaping of the edge. Usually, measures are taken to improve the accuracy of slit cutting and the accuracy of roll groove design for roll forming. For this reason, a method has been adopted in which, for example, after the grooved rolling of the strip material is performed off-line, a slit cutting process of the plate width is performed on another line. Although a groove processing method of a strip material for forming a circular shape of an edge portion has been proposed (for example, Japanese Patent Application Laid-Open No. 4-157017), the width and end face shape of the strip material vary and are still insufficient. is there.

[0014] Therefore, even if the strip material grooved by the current groove processing method is roll-formed and welded, welding becomes unstable, and variation over time such as reduction in welding strength cannot be eliminated.

At present, preparations are being made to use a substitute for the heat exchange medium, which is a fluorocarbon that destroys the ozone layer before it reaches the ozone layer.

Unfortunately, heat exchange characteristics of the alternative CFCs are reduced by about 20%. Therefore, measures must be taken to eliminate urgent CFCs.

Although it is necessary to increase the heat exchange area of the heat transfer tube by an amount corresponding to the decrease in the heat exchange characteristic, there is a problem in weight and size. There is.

The present invention has been made in view of such problems of the prior art.
Grooved rolling for welded heat transfer tubes that can improve the welding quality by improving the butting condition by tubular forming by performing grooved rolling without causing variations in the width and edge shape of the strip. An object of the present invention is to provide a flattened heat transfer tube using an apparatus and a strip processed by the apparatus.

[0019]

In order to achieve the above-mentioned object, the present invention provides a welding heat transfer pipe strip material grooved rolling apparatus, wherein a plurality of grooved ridges are provided at a predetermined pitch. And a groove forming roll composed of side edge rolling portions provided on both sides thereof, and a groove-rolling process performed on the material by a support roll disposed opposite to the groove forming roll. When the groove is formed, the ridge of the groove forming roll is pushed into the raw material when the groove is formed, and is pushed out to both sides of the ridge when the groove is formed. At least one buffer area for absorbing the variation is provided, and one or both of the grooved roll and the support roll is provided with a restraining portion for restraining the width of the strip in the width direction.

It is also preferable to provide a buffer region for the strip member between the side edge rolling section and the grooved ridge adjacent thereto.

In the case of producing a flat heat transfer tube strip for welding, the groove at a predetermined pitch position among the grooves of the roll is formed shallow and flat.

The flattened heat transfer tube is formed by inserting a corrugated inner fin into a flat tube with a groove on the inner surface of the weld made using a strip having a brazed portion of a corrugated inner fin made by a rolling device with a grooved groove. .

[0023]

When the strip is pressed by the groove forming roll, the grooved ridge enters the strip surface and is grooved. At this time, the strip member pressed and extruded from the groove portion flows to a portion that does not press the strip material, increases the thickness of that portion, fills a gap formed between the grooved ridges, and has a predetermined height. Form ridges.

At this time, if the thickness t ₀ of the raw material is larger than the reference value, the material that cannot be inserted between the grooved ridges flows in the width direction of the material and the width of the material becomes smaller. The width of the strip is prevented by the restraining portion from spreading, and the width of the strip is absorbed by the buffer area.

For this reason, the width of the strip is constant, and the force acting on the end of the strip does not change so much. Therefore, the width of the strip is uniform and the grooved strip has an even end face. Wood is obtained.

When a low ridge is provided at the center of the buffer area of the grooved roll, the low ridge prevents the swelling of the ridge at the center of the buffer area, and the ridge from both sides is removed. By flowing into the buffer area, it is possible to prevent an excessive force from being applied to the end of the strip.

When a buffer area is provided between the side edge rolling portion and the grooved ridge, the strip member flowing from the side edge rolling portion or the groove forming portion can be absorbed. Therefore, the fluctuation of the force generated in the restraint portion is further reduced.

Since the processed surface of the groove material of the groove forming roll is symmetrical, the processed material has a symmetrical shape with its center line as a symmetric axis. Since twisting does not occur during tubular forming,
The abutting state of the abutting portion by the tubular forming becomes uniform, and uniform welding can be performed.

Since the groove at a predetermined pitch position among the groove portions of the roll is shallow and the bottom portion is flat, the ridge of the strip material processed in this shallow groove portion is lower than the other ridges and the top surface. Is formed flat and becomes a brazing portion of the corrugated inner fin.

Therefore, if a flat tube with a groove on the inner surface of the weld is made using this strip and the corrugated inner fin is inserted therein,
Since the inner fin abuts on the brazed portion with a shallow groove, by brazing the abutted portion, an inner fin-shaped welded flat heat transfer tube can be obtained.

[0031]

An embodiment of the present invention will be described with reference to the drawings.

Example 1 In FIGS. 1 and 2, reference numerals 1 and 8 denote a groove forming roll and a supporting roll in a strip rolling machine, 10 denotes an original strip,
Reference numeral 11 denotes a grooved and rolled strip.

In FIG. 1A, the groove forming roll 1 is composed of a groove forming portion 1A and side edge rolling portions 1B provided at both ends of the groove forming portion 1A. The groove forming portion 1A is used for forming a groove in the raw material 10. A number of grooved ridges 2 having a substantially trapezoidal cross section with a pitch p, a height h ₂ , and an angle θ, and a central portion of the groove forming portion 1A, which contact with the surface of the original material during grooved rolling. Low ridge 3 to touch
It has.

Further, in FIG. 1 (b), the side edge rolling portion 1B
Is made up of an end rolled portion 5 having a small diameter portion 7 and a slope portion 6 connected to the base of the grooved ridge 2 'at the end of the groove forming portion 1A. The width w ₂ of the small diameter portion 7 is equal to the width of the groove 4 in the groove forming portion 1A.
It is constituted than the width w ₁ to large.

The support roll 8 has flanges 9 at both ends for preventing the strip material from extending in the width direction generated at the time of groove processing.
The height of the flange 9 is set at the end rolling portion 5 of the groove forming roll 1.
When the flange 9 abuts, the distance between the grooved ridge 2 ′ of the groove forming portion 1 A and the surface of the support roll 8 becomes a predetermined thickness tmin of the groove 12 of the grooved member 11. It has become.

In FIG. 1C, the width of the small diameter portion 7 'connected to the base of the grooved ridge 2' in the side edge rolling portion 1B is equal to the width w of the groove 4 in the groove forming portion 1A. Instead of making it the same as ₁ , the diameter is configured to be smaller than the diameter of the groove 4.

The groove forming roll 1 and the supporting roll are disposed so that the flange of the supporting roll 8 is in contact with the end pressing portion 5 of the groove forming roll 1 configured as described above, and the two rolls are rotated to interpose the roll. Through the raw material 10 and grooved.

When the raw material 10 enters between the rolls 1 and 8, the grooved ridge 2 in the groove forming portion 1A of the roll 1 presses the surface of the raw material to the thickness tmin to form the groove 12. I do.

The strip member pushed out from the pressing groove 12 by the ridge 2 increases the thickness of the adjacent portion to fill the groove 4 of the roll 1 to form a ridge 13 having a thickness of tmax. The thickness t ₀ of the groove 4 is larger than the reference value.
Article members that could not enter into the enters the gap portion g ₁ which moves in the width direction of the strip material is formed on both sides of the lower protrusion 3 provided in the center portion of the roll 1.

That is, the gap g ₁ functions as a buffer region C ₁ for relaxing the elongation of the strip 11 in the width direction.

At the same time as the groove processing, both ends of the strip 11 are rolled by the end rolling portion 1B. However, the widthwise extension of the strip 11 due to the rolling is prevented by the flange 9 of the support roll 8, so that Article member extruded by same reference value or more volume as above when pressed by rolling enters the air gap g ₂ which is formed on the small diameter portion 7.

[0042] That is, it functions as a buffer zone C ₂ to relax the extension of the width direction of the air gap g ₂ also strip member 11.

According to this embodiment, since the widthwise elongation of the strip produced during the grooved rolling is restricted by the support rolls and can be absorbed in the buffer areas C ₁ and C ₂ , the grooved rolling is performed. Even if there is some variation in the thickness, width, and the like of the raw material, the width and the end shape of the end of the strip 11 do not vary.

Example The average pitch P of the grooved ridges 2 of the groove forming roll 1 is 0.
55 mm, height h ₂ (= tmax−tmin) 0.16
mm, the inclination θ is about 10 ° and the thickness is 0.3m
m, an off-line grooving process is performed on a raw material made of phosphorus deoxidized copper having a sheet width of 20.8 mm, and an average groove pitch of 0.55
mm, thickness tmax is 0.38, tmin is 0.22,
A strip having a groove angle of 10 ° was obtained.

This grooved strip was formed over the entire periphery by a roll form, rounded to a finish diameter of 6.35 mm, and the butted portion was high-frequency welded with an electric resistance sewing machine.

In the grooving rolling, the width of the strip can be regulated accurately and accurately, and the grooving can be carried out.
° (conventional + 20 °, −0 °), step variation ± 0.25
mm (conventionally ± 0.1 mm).

For this reason, the welding strength is greatly improved, the quality maintenance for a long time is also improved to 1/50 km (conventional 1/10 km), the reliability of welding quality is greatly improved and stabilized, and the yield is also improved. It increased from 80% to 95%.

Thus, adjustments due to material fluctuations were reduced, and the operation rate was improved from 70% of the prior art to 95%.

Since the abutment angle and the unevenness of the steps are small, the life of the consumables is increased, for example, the life of the seam guide is extended from 100 hours to 400 hours, and the life of the squeeze roll is extended from 400 hours to 800 hours. Has greatly improved.

In the above embodiment, the buffer area C ₁ shown in FIG.
Is provided at the center, and the buffer areas C ₂ and C ₃ shown in FIGS. 1B and 1C are provided at the side ends, but any of the center or side ends C ₁ , C ₂ and C ₃ is provided. It is good.

Further, in the above embodiment, the shape of the grooved ridge of the groove forming roll is trapezoidal and the trapezoidal groove is machined. However, the groove shape itself can be freely determined by each manufacturer. ,
The following conditions should be satisfied.

A. Be symmetrical, b. There is at least one continuous buffer area in the width direction of the groove forming roll in the length direction of the material, c. At both ends of the groove forming roll or the supporting roll, there are flange portions that prevent the width of the strip from spreading, d. The thickness te of the end of the strip is (tmax + tmin) /
2 ≧ te> tmin.

Embodiment 2 Referring to FIGS. 3 and 4, reference numeral 1 'denotes a groove forming roll of the inner fin-shaped welded flat tube member, and reference numeral 4' denotes a shallow and flat groove 4 at a predetermined pitch position in the groove 4 of the roll 1 '. Groove formed in.

Reference numeral 10 'denotes an aluminum strip, 11' an aluminum strip processed by a roll 1 ', and 16 a brazing projection formed by a groove 4' of the roll 1 '.

The other construction is the same as that of the first embodiment shown in FIGS. 1 and 2 except that the width of the roll 1 is slightly different from that of the first embodiment. Is omitted.

Thus, similarly to the first embodiment, the raw material 10 ′
Is grooved and rolled by a groove forming roll 1 'to produce a strip material 11'. This strip material 11 ′ is formed into a flat tube at the entire outer periphery, and the butted portion is welded by an electric resistance welding device to produce a flat tube with an inner surface groove.

Referring to FIGS. 5 and 6, the flat tube 15 with the inner groove is cut into a predetermined length (about 150 to 300 mm) so as to be adapted to the length of the car cooler. The brazing agent 18 is applied, and the wavy fins 17 of substantially the same length on which the brazing agent 18 has been applied have both protruding surface portions having the brazing ridge 1.
6 and is inserted into the flat tube 15.

Then, the flat tube 16 into which the wavy fins 17 have been inserted is heated in a furnace, and both protruding portions of the wavy fins 17 are brazed to the brazing ridges 16 on the inner surface of the flat tube, as shown in FIG.
A flat heat transfer tube with an inner fin type inner surface groove as shown in (a) is manufactured.

Example The average pitch P of the grooved ridges 2 of the groove forming roll 1 is 0.
55 mm, height h ₂ (= t _max −t _min ) 0.16 mm,
Using a material having a slope θ of about 10 °, a three-layer clad aluminum raw material having a thickness of 0.3 mm and a width of 42.2 mm is subjected to grooving rolling off-line, and a groove pitch average of 0.5.
A strip having a thickness of 5 mm, a thickness t _max of 0.38, a t _min of 0.22 and a groove angle of 10 ° was obtained.

The grooved strip was formed over the entire outer periphery by a roll form, and the butted portion was subjected to high frequency welding by an electric resistance welding device so as to make the shape of the post-deflection and the finished major diameter 20 × 2 mm in rectangle.

In the grooving rolling process, the width of the strip material can be fixed and accurately regulated for grooving, so that the butt by the entire outer periphery forming has little variation, and the butt angle ± 2 ° (conventional + 20 °, conventional + 20 °, −0 °), step variation ± 0.025
mm (conventionally ± 0.1 mm).

For this reason, the welding strength is greatly improved, the quality maintenance for a long time is improved to 1/50 km (1/10 km in the past), the reliability of welding quality is greatly improved and stabilized, and the yield is also improved. It increased from 83% to 98%.

Thus, adjustments due to material fluctuations were small, and the operating rate was improved from 72% to 97%.

Since the abutment angle and the unevenness of the steps are small, the life of the seam guide is increased from 350 hours on average to 920 hours on average, and the life of the squeeze roll is increased from 800 hours on average to 3000 hours on average. The life of the product has been greatly improved.

[0065] The buffer area C ₁ of FIG. 4 in the above embodiment (i) in the center, FIG. 4 (b), is provided on a side end portion of the buffer area C _2, C ₃ of (c), the central portion Or buffer areas C ₁ , C ₂ , C
Any of the _three configurations may be provided.

In the above-described embodiment, the shape of the grooved ridge of the groove forming roll is trapezoidal, and the groove is formed in a trapezoidal shape. What is necessary is just to satisfy the conditions as follows.

A. The groove shape is left-right symmetrical, except that the fin brazing portion is not symmetrical.

B. At least one in the middle direction of the groove forming roll
There must be a continuous buffer area along the length of the material.

C. There must be flanges at both ends of the groove forming roll or the support roll to prevent the strip from spreading in the middle direction.

[0070]

Since the present invention is configured as described above, the following effects can be obtained.

(1) The width of the strip member, which spreads in the width direction, is absorbed in the buffer area, and both end faces can be restrained without difficulty, so that the grooved strip material having a uniform width and an even end face shape. Can be continuously processed.

(2) Since the grooved member does not twist when it is formed into a tube, the ends can be abutted uniformly, so that uniform welding can be performed.

(3) For this reason, the reliability and the yield of the welding heat transfer tube are improved, and the operation rate of the manufacturing apparatus for the welding heat transfer tube is improved.

(4) Since there is no variation in the welded portion,
The life of consumables such as seam guides and squeeze rolls is greatly improved.

(5) By adopting a flat heat transfer tube in which corrugated fins are inserted in a flat tube with an inner surface groove, an effect of improving heat exchange characteristics by 20% or more can be obtained as compared with a conventional flat heat transfer tube having no groove on the inner surface. Was done.

[Brief description of the drawings]

FIGS. 1A, 1B, and 1C are cross-sectional views showing a groove forming state and a side edge rolling state according to the first embodiment.

FIGS. 2A and 2B are cross-sectional views showing a raw material and a groove-rolled material according to Example 1. FIG.

FIGS. 3A, 3B, and 3C are cross-sectional views illustrating a groove forming state and a side edge rolling state according to the second embodiment.

FIGS. 4A and 4B are cross-sectional views showing a raw material and a groove-rolled material according to Example 2. FIG.

FIGS. 5A and 5B are a cross-sectional view of a main part of a flat heat transfer tube according to a second embodiment and an enlarged view of a main part of an inner fin.

FIG. 6 is an explanatory view of inserting an inner fin according to the second embodiment.

FIG. 7 is a schematic view showing a method of manufacturing a welded heat transfer tube with an inner groove.

FIGS. 8A, 8B, and 8C are cross-sectional views showing conventional heat transfer tubes for a car cooler, respectively.

[Explanation of symbols]

 1, 1 '... groove forming roll 1A ... groove forming section 2B ... side edge rolling section 2, 2' ... grooved ridges 3 ... ridges 4 ... groove section 5 ... end rolling section 6 ... slope section 7 ... small diameter section 8 ... Support Roll 9 ... Flange 10,10 '... Raw Material 11 ... Roll Material 12 ... Groove 13 ... Welded Heat Transfer Tube 14 ... Inner Fin Type Flat Heat Transfer Tube with Inner Groove 15 ... Inner Groove Flat Tube 16 with Brazing Projections 17, 28, 29 Corrugated fins 18 Brazing material 21 Groove-rolled portion 22 Tubular forming portion 23 ERW device 25 Harmonica tube 26 Inner fin tube 27 Flat tube

Claims (5)

(57) [Claims] 1. A groove forming roll comprising a groove forming portion provided with a large number of grooved ridges at a predetermined pitch and side edge rolling portions provided on both sides thereof, and arranged opposite to the groove forming roll. A grooved roll is formed on a strip by a support roll. The groove-formed roll has a symmetrically processed surface of the strip, and a grooved portion is provided with a buffer region having a void at least at one position. And a support member provided on one or both of the support rolls for restraining the width of the strip in the width direction. 2. The grooved rolling device for a welded heat transfer tube according to claim 1, wherein a low ridge is provided at the center of the buffer region of the grooved roll to contact the surface of the raw material. . 3. The strip for a welded heat transfer tube according to claim 1, wherein a buffer zone having a gap is provided between the side edge rolling section and the grooved ridge adjacent thereto. Rolling machine with material groove. 4. A groove portion at a predetermined pitch position of a groove portion of a roll is formed to be shallower and flatter than other groove portions, and a braided portion of a corrugated inner fin is formed on a strip material. 4. The rolling device with grooved material for a welded heat transfer tube according to any one of claims 1 to 3. A corrugated inner fin is inserted into a flat tube with a groove on the inner surface of the weld using a rod material rolled by the grooved rolling device for a heat transfer tube for a heat transfer tube according to claim 4. Welded flat heat transfer tube.