JP5280726B2 - HEAT EXCHANGER, MANUFACTURING METHOD THEREOF, AND OUTDOOR UNIT OF AIR CONDITIONER USING THE HEAT EXCHANGER - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the quality of a heat exchanger manufactured by reducing load generated when a billet is drawn out after completion of tube expansion without reducing holding force against load in a tube axis direction generated when a tube of a heat exchanger is expanded. <P>SOLUTION: In the method for manufacturing the heat exchanger, the billet 4 is pressed into the tube through a tube opening to form an expanded tube part 2a with a specified length, and a tapered part 2b having a small diameter at a position close to the tube port and a large diameter at a position far from the tube port is formed at the outer surface of the expanded tube part 2a. Thereafter, a holding part 6 holds the tapered part 2b, the billet 4 is pressed into the inner part from the tube port to expand the tube, and a fin 1 and the tube 2 are made to be integrated with each other. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a heat exchanger used for an outdoor unit or the like of an air conditioner, a manufacturing method thereof, and an outdoor unit of an air conditioner.

In a heat exchanger used for an air conditioner or the like, a plurality of fins having through holes are stacked, a hairpin tube or a straight pipe is inserted into the through holes, and a billet having a pipe diameter to be expanded is press-fitted into the pipe. Then, the pipe is expanded, and the fin and the pipe are brought into pressure contact to be integrated. At the time of press-fitting, the pipe opening on the side where the billet is inserted is fixed to prevent the pipe from receiving a compressive load in the pipe axis direction accompanying the expansion of the pipe and shortening the pipe length.
The tube mouth is fixed according to the following procedure. That is, when only a predetermined length of the tube opening portion is once expanded, a gripping body is disposed on the outer surface of the expanded portion, and the diameter is reduced, the outer surface of the tube is depressed into a substantially rectangular shape in an axial sectional view and plastically deformed. Here, when the convex part (grip part) at the tip of the gripping body bites into the depressed part, it is possible to withstand a large load in the tube axis direction during pipe expansion.
At this time, along with the plastic deformation on the tube outer surface side, the inner surface side is also plastically deformed so as to have substantially the same shape, and a bulge having a substantially rectangular shape in the axial cross-sectional view is formed in the tube axis direction (for example, Patent Document 1). reference).

Japanese Patent Laid-Open No. 2000-301271 (pages 4-6 and 2-5)

  However, in the conventional heat exchanger, since the protruding in a substantially rectangular shape in the axial cross-sectional view formed on the inner surface of the tube, when the billet is pulled out to the tube mouth side after the tube expansion, the billet is caught by the protruding and cannot be easily pulled out. . Therefore, when the internal frictional resistance of the pipe increases, an excessive load is applied to the pipe or billet, and the billet or pipe may be damaged. On the other hand, if the amount of depression on the outer surface of the pipe expansion part is shallow, the protrusion to the inner surface side can be reduced and the load for pulling out the billet can be reduced, but the gripping force during pipe expansion is reduced, so the gripping part slips during pipe expansion. There was a problem.

  The present invention has been made to solve the above-described problems, and at the time of pulling out the billet after the end of the pipe expansion without reducing the gripping force to resist the load in the direction of the pipe axis that occurs during the pipe expansion of the heat exchanger. An object is to reduce the generated load and improve the manufacturing quality of the heat exchanger.

The heat exchanger manufacturing method according to the present invention includes a gripping device that is divided into a plurality of parts in the circumferential direction, and has a tapered shape formed on the inner circumference that decreases in diameter toward the inner side from the end face side. Prepare the body, and insert the pipe into the through hole of the end plate and the through holes of the fins that are stacked at intervals, leaving a protrusion longer than the length from the end surface of the gripping body to the smallest diameter part of the tapered shape. The first step to pass through, and the gripping body is arranged so that the end surface comes into contact with the end plate, and a billet for expanding the tube is press-fitted from the tube port of the tube to form a tube expanding unit of a predetermined length in the tube port of the tube A second step, a third step of reducing the diameter of the gripping body, forming a tapered portion on the outer surface of the tube expansion portion on the outer surface of the tube expansion portion with a small diameter near the tube opening and a large diameter on the far side, and a billet tube The tube is expanded by press-fitting from the mouth to the end, and the end Comprising a fourth step of integrating the rate and fin and the tube, the.

  According to the present invention, the outer surface of the tube is formed into a tapered shape so that the diameter on the side near the tube opening is small and the diameter on the far side is large, and the tube is expanded after grasping this portion. The gripping body can be hooked on the step having the same depth as the conventional one provided on the outer surface of the tube, and the gripping force at the time of tube expansion is not reduced. Further, the step on the outer surface of the tube far from the tube port is reduced, and the protrusion of the inner surface of the tube corresponding to that portion is also reduced, so that the billet pull-out load after completion of the tube expansion can be reduced.

Embodiment 1 FIG.
FIGS. 1 to 6 show the configuration of a heat exchanger and its manufacturing apparatus and its manufacturing method in Embodiment 1 for carrying out the present invention.
FIG. 1 (a) shows a main equipment configuration of a heat exchanger and an apparatus for manufacturing the heat exchanger. The heat exchanger includes a fin 1 for radiating heat in the air, and a refrigerant passing through the inside. It is comprised from the pipe | tube 2 which conveys the heat | fever to the fin 1, and the side plate 3. As shown in FIG. On the other hand, the manufacturing apparatus forms the mandrel 5 for supporting the billet 4 press-fitted into the pipe for expansion of the pipe, the billet 4 for transmitting the driving force to the billet 4, and the pipe opening, and the vicinity of the pipe opening when expanding the pipe. A gripping body 6 to be gripped, a sleeve 7 for reducing and expanding the diameter of the gripping body by moving forward and backward while rotating around the tube axis, and a flare punch 8 for forming a flare portion at the tube opening.
FIG. 1 (b) shows an enlarged cross section of the gripping body 6 viewed from the axial direction. Since the gripping portion 6a is divided into a plurality of parts in the circumferential direction, the gripping portion can be reduced by narrowing the interval between them. It is possible to reduce the diameter of 6a as a whole.
Further, the gripping body 6 and the sleeve 7 have tubular tapered surfaces 6b and 7b having the same gradient. A male screw is provided on the outer surface of the taper surface 6b of the gripping body 6, and a female screw is provided on the inner surface of the taper surface 7b of the sleeve 7. Has been processed. Here, when the sleeve 7 is rotated and moved forward in the right direction in the drawing, both screws mesh with each other to reduce the diameter of the gripping portion 6a. The diameter of the part 6a can be increased.

Next, a method for expanding the tube and a method for forming a tube near the tube opening will be described.
First, as shown in FIG. 2, the end plate 3 and the plurality of fins 1 are overlapped and arranged at a predetermined interval, and the tube 2 is inserted into a through hole provided in advance in the fin 1 and the end plate 3. Here, the gripping body 6 that forms and grips the tube opening is disposed so as to abut on the end plate 3, and a predetermined length to be formed in the tube opening is ensured. Next, the mandrel 5 is moved forward in the right direction in the drawing, and the billet 4 provided at the tip thereof is press-fitted into the pipe from the pipe opening, thereby forming the expanded portion 2a having a predetermined length.
Next, as shown in FIG. 3, the diameter of the grip portion 6 a of the grip body 6 is reduced by moving the sleeve 7 forward while rotating. Since the grip portion 6a has a tapered shape with a small diameter on the side close to the tube opening and a large diameter on the far side, the same tapered shape 2b is formed on the outer surface of the tube. The gripping portion 6a is fitted into the tapered recess, and the tube 2 can be gripped against a strong load in the tube axis direction when the tube is expanded.
After gripping the tube as described above, the mandrel 5 is further advanced in the depth direction of the tube as shown in FIG. 4, and the billet 4 is press-fitted to the vicinity of the opposite end (not shown), and the fin 1 is present. The expanded pipe portion 2c is formed over the entire length. As a result, the tube 2, the fin 1 and the end plate 3 are integrated to form a heat exchanger. At this time, since the tube forming is performed in a state where the tapered portion 2b of the tube opening portion is held and the opposite end portion (not shown) of the tube is fixed, the tube length is reduced even if the billet 4 is press-fitted and expanded. There is no.
Next, as shown in FIG. 5, the flare punch 8 is press-fitted into the tube opening of the tube 2 to form the flare portion 2d. In order to join adjacent pipes 2 to form one refrigerant circuit, brazing is performed by using a U-shaped pipe joint, but this flare portion 2d is U-shaped. Shaped pipe joints for insertion and brazing.
Since the molding operation to be applied to the pipe 2 is completed with the above-described contents, finally, as shown in FIG. 6, the heat exchanger body and the manufacturing apparatus are separated. First, while rotating the sleeve 7, the sleeve 6 is moved backward in the left direction of the drawing to increase the diameter of the gripping portion 6a. Next, the flare punch 8, the mandrel 5, and the billet 4 are retracted and pulled out from the pipe opening.

According to the method for manufacturing a heat exchanger as described above, the pipe outer surface 2b is formed in a tapered shape so that the diameter on the near side from the pipe port is small and the diameter on the far side is large. In addition, the gripping portion 6a of the gripping body 6 can be hooked on the step having the same depth as the conventional one, and the gripping force during tube expansion shown in FIG. 4 is not reduced.
Further, in the last step shown in FIG. 6, when the mandrel 5 is retracted and the billet 4 is pulled out from the pipe, the step on the pipe outer surface far from the pipe opening is reduced, and the corresponding protrusion on the pipe inner face is also reduced. Therefore, the billet 4 is not hooked to the edge when being pulled out as in the prior art, and the pulling-out load can be reduced. As a result, even when the internal frictional resistance of the pipe increases, the pipe or billet is not damaged due to an excessive load, and the manufacturing quality of the heat exchanger can be improved.
Also, the end opposite to the end of the tube shown in FIGS. 1 to 6 is fixed when the tube 2 is expanded, but when the billet 4 is pulled out from the tube, the load received by this part should be reduced. Therefore, the dent of this part can be eliminated, and a heat exchanger excellent in appearance can be obtained.
Further, since the gripping portion 6a of the gripping body 6 has a tapered shape, the load when the diameter of the gripping portion 6a is reduced can be reduced, so that the load on the cylinder or the like for driving the sleeve 7 can be reduced. There is also.
On the other hand, since the heat exchanger manufactured by this method is not subjected to a strong tensile load at the time of billet pulling at the time of manufacture, the surroundings of the pipe opening may be thinned by receiving a strong overload like conventional products. It is advantageous in terms of mechanical strength and has excellent durability.

Embodiment 2. FIG.
FIG. 7 shows the main equipment configuration of the heat exchanger and the apparatus for manufacturing the heat exchanger in the second embodiment for carrying out the present invention. The difference from the first embodiment is that the gripper 6 The grip portion 6c has a plurality of tapered shapes. Along with this, a plurality of stages of tapered shapes 2e are formed on the outer surface of the pipe opening. Since the other device configurations and operations are the same as those in the first embodiment, details are omitted. Also, the manufacturing method is the same as that described in the first embodiment shown in FIGS.

  According to the method for manufacturing a heat exchanger as described above, it is possible to share the load in the tube axis direction generated at the time of pipe expansion on the outer surface of the tube port portion by a surface perpendicular to the plurality of tube shafts of the 2e portion. Therefore, since the load to be borne per stage is reduced as compared with the first embodiment, the gripping force in the tube axis direction is kept the same even though it is possible to reduce the depth of the stage. be able to.

Here, in order to compare the effect with the first embodiment, an example in which the gripping force is measured when the number of steps of the tapered shape of the gripping portion 6c and the pitch are changed is shown below. When a 0.47 mm thick aluminum tube is used and the outer diameter of the tube is reduced from φ7.4 mm to φ7.0 mm (reduction amount Δd = 0.4 mm), the taper pitch P is changed. The gripping force at that time was measured (refer to FIG. 8 (a) for the definition of the dimensions of Δd and P). The results are plotted as shown in FIG. 8 (b), with Δd / P (dimensionless amount representing edge sharpness) on the horizontal axis and gripping force (N) on the vertical axis. It can be seen that there is an optimum shape with a maximum gripping force around 0.1 ≦ Δd / P ≦ 0.3.
This can be explained as follows. That is, if Δd / P is increased and the edge is sharpened, many steps can be provided. However, since the V-groove of the gripping portion 6c is steep, the outer surface of the tube is less likely to follow the V-groove deeply. The catching of the V-grooves of the grip portion and the outer surface of the pipe per step becomes shallow. Conversely, if Δd / P is reduced to make the edge dull, the V-groove of the gripping part becomes a gentle shape, so that the outer surface of the tube is formed relatively accurately following the shape of the gripping part, and V per step Although the catch of the groove can be deepened, the number of steps cannot be increased. The gripping force is determined by the number of catches per step and the number of steps, and as described above, there is a trade-off relationship between the pitch P and there is an optimum value of P (Δd / P) at which the gripping force becomes maximum, That is the range indicated by the above inequality.
The value of P is constrained by the length of the tube opening, and Δd is constrained by the thickness of the tube, but by selecting Δd / P that maximizes the gripping force as described above, In comparison, the gripping force can be increased. In addition, the measurement of the gripping force was performed in a state where Δd is constant, but the gripping force is naturally reduced when Δd is decreased. However, by selecting Δd / P in the vicinity of the aforementioned maximum value, it is possible to maintain a gripping force equivalent to that having the one-step tapered shape shown in the first embodiment even if Δd is reduced. I know that there is.

In addition, since the tapered shape is formed in the tube opening portion so that the diameter on the side close to the tube opening is small and the diameter on the distant side is large, the load at the time of drawing the billet is reduced as in the first embodiment. However, since the bulge formed on the inner surface of the pipe is smaller than that of the first embodiment, the excess weight can be further reduced.
On the other hand, the heat exchanger manufactured by this method is characterized by excellent mechanical strength and durability, similar to that obtained by the method of the first embodiment.

Embodiment 3 FIG.
FIG. 9 shows the main equipment configuration of the heat exchanger and the apparatus for manufacturing the heat exchanger according to the third embodiment for carrying out the present invention. The difference from the first embodiment is that the gripper 6 The cross section of the grip portion 6d is elliptical as shown in FIG. Since the other device configurations and operations are the same as those in the first embodiment, details are omitted. The manufacturing method is also the same as that described in Embodiment 1 shown in FIGS.
By forming the tube 2 using the gripping portion 6d, a tapered shape 2f having an elliptical cross section is obtained at the tube opening.
Further, in FIG. 9 (a), the gripping portion of the gripping body has a one-step tapered shape, but a manufacturing apparatus for carrying out the present invention is also applicable to the one having a plurality of steps presented in the second embodiment. Can be configured.

According to the manufacturing method of the heat exchanger as described above, since the diameter on the side close to the tube opening is small and the diameter of the tube back is large, it is formed into a single-stage taper shape or a multi-stage taper shape. The same effect as described in the first or second embodiment is obtained.
In order to ensure the safety of the user in the air conditioner, the pressure resistance of the outdoor unit is designed to be lower than that of the indoor unit. In the outdoor unit, the heat exchanger may be designed to have a pressure resistance lower than that of the compressor. It has been established. According to the method for manufacturing a heat exchanger according to the present invention, it is possible to arbitrarily design the pressure strength of this portion by changing the ellipticity of the ellipse by making the cross-sectional shape of the tube forming portion 2f elliptical. Therefore, there is an advantage that the degree of design freedom increases.

Embodiment 4 FIG.
FIG. 10 shows the main equipment configuration of the heat exchanger and the apparatus for manufacturing the heat exchanger according to the fourth embodiment for carrying out the present invention. The difference from the first embodiment is that the gripper 6 A portion 6e that matches the outer surface shape of the predetermined flare portion 2d is provided on the inner surface. Since the other device configurations and operations are the same as those in the first embodiment, details are omitted. The manufacturing method is also the same as that described in Embodiment 1 shown in FIGS.
10 shows a one-stage taper shape in which the gripping portion of the gripping body is 6a, a manufacturing apparatus for carrying out the present invention similarly in 6c having a plurality of stages presented in the second embodiment. Can be configured.

According to the heat exchanger manufacturing method as described above, the heat exchanger is formed into a one-step tapered shape (2b) having a small diameter on the side close to the tube opening and a large diameter on the far side, or a plurality of steps (2e). Therefore, the same effect as described in the first or second embodiment is obtained.
Further, in the conventional method, when the flare portion 2d is formed, if the tube 2 is thick, there is a problem that the molding accuracy of the flare portion is deteriorated and the airtightness at the connection portion is deteriorated. According to the heat exchanger manufacturing method as described above, the flare portion 2d is formed by being sandwiched between the flare punch 8 and the gripping member inner surface 6e, and therefore the flare portion 2d can be accurately formed even if the tube 2 is thick. As a result, it is possible to reliably braze the connecting portion, and thus there is an effect that the airtightness of this portion can be kept good.

Embodiment 5 FIG.
The outdoor unit of the air conditioner using the heat exchanger according to the present invention described above will be described with reference to FIG. The outdoor unit includes a heat exchanger 10, a fan 11, a compressor 12, an electrical component box 13, a bottom plate 14, a housing 15, and a top plate 16. On the bottom plate 14 of the outdoor unit, a heat exchanger 10 curved in an L shape from the left side surface to the rear rear surface is installed, and a fan 11 and a compressor 12 are disposed on the front side of the heat exchanger 10. In the upper part, an electrical component box 13 that supplies power to each device and controls them is arranged. In addition, the heat exchanger 10 manufactured by the method described in the first to fourth embodiments is used.
Here, the operation of the outdoor unit of the air conditioner will be described in the case of cooling operation. The refrigerant gas warmed by the indoor unit returns to the outdoor unit and is compressed by the compressor 12 to become a high temperature. The refrigerant gas is sent to the heat exchanger 10, but is cooled by the outside air blown by the fan 11, and the refrigerant is liquefied and sent again to the indoor unit. By the operation described above, the refrigerant heated in the indoor unit can be cooled in the outdoor unit, and the cooling target room can be cooled.

Generally, in the outdoor unit of an air conditioner, the area around the heat exchanger tube mouth is subjected to plastic processing such as pipe expansion and gripping molding, and is also affected by heat due to brazing. It is one of the weak parts. About the outdoor unit of the air conditioner which concerns on this invention, since the heat exchanger by the invention shown in Embodiment 1 thru | or 4 is used, it does not receive the strong tensile load at the time of billet extraction at the time of manufacture. Therefore, it is advantageous in terms of mechanical strength and excellent in durability without being thinned around the pipe opening due to strong pulling excess as in the conventional product.
Therefore, even when viewed as an outdoor unit of an air conditioner, it can be said that the device according to the present invention is excellent in durability.

It is sectional drawing which shows the heat exchanger by Embodiment 1 of this invention, and its manufacturing apparatus. It is sectional drawing which shows the condition of the edge part pipe expansion in the manufacturing method by Embodiment 1 of this invention. It is sectional drawing which shows the condition of the taper part shaping | molding in the manufacturing method by Embodiment 1 of this invention. It is sectional drawing which shows the condition of the full length pipe expansion in the manufacturing method by Embodiment 1 of this invention. It is sectional drawing which shows the condition of the flare part shaping | molding in the manufacturing method by Embodiment 1 of this invention. It is sectional drawing which shows the condition of isolation | separation of the heat exchanger and manufacturing apparatus in the manufacturing method by Embodiment 1 of this invention. It is sectional drawing which shows the heat exchanger by Embodiment 2 of this invention, and its manufacturing apparatus. It is a figure which shows the measurement result of the gripping force at the time of changing the shape of the holding part 2 by Embodiment 2 of this invention. It is sectional drawing which shows the heat exchanger by Embodiment 3 of this invention, and its manufacturing apparatus. It is sectional drawing which shows the heat exchanger by Embodiment 4 of this invention, and its manufacturing apparatus. It is a perspective view which shows the outdoor unit of the air conditioner by Embodiment 5 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fin 2 Pipe 2a Expanding part 2b Tapered part 2d Flare part 4 Billet 6 Grasping body 8 Flare punch 10 Heat exchanger 11 Fan 12 Compressor 13 Electrical component box 14 Bottom plate 15 Case 16 Top plate

Claims (8)

Prepare a gripping body that is divided into a plurality of parts in the circumferential direction and has an inner circumference with a tapered shape with an inner diameter that decreases from the end face side toward the inner side. multiple superimposed through holes of the fins spaced, leaving a longer protruding than the length up to the minimum diameter portion of the tapered from the end surface of the gripping member, a first step to communicating insert the tube,
The gripping body is disposed so that the end surface is in contact with the end plate, and a billet for expanding the tube is press-fitted from the tube port of the tube, thereby forming a expanded portion of a predetermined length in the tube port portion of the tube . Process ,
A third step of reducing the diameter of the gripping body, and forming the tapered portion on the outer surface of the expanded portion with a small diameter on the side close to the tube opening and a large diameter on the far side ;
And a fourth step of performing the tube expanding, to integrate the said end plate and said fins tube by press-fitting the billet at the back than the tube mouth,
A method of manufacturing a heat exchanger comprising: The method for manufacturing a heat exchanger according to claim 1, wherein the gripping body has a plurality of stages of the tapered shape in a tube axis direction. The method of manufacturing a heat exchanger according to claim 1 or 2, wherein the grip body has an elliptical cross-sectional shape. The gripping body has an inner surface having a shape that matches the outer surface shape of the flare portion provided in the tube opening, and the tube opening is sandwiched between the flare punch that is press-fitted into the tube from the tube opening and the gripping body. A fifth step of forming the flare portion in the pipe opening portion by:
The manufacturing method of the heat exchanger of any one of Claims 1 thru | or 3 provided with these . A plurality of fins that have through holes and are stacked at intervals ;
An end plate disposed at an end of the fin having a through hole and a plurality of which are overlapped with each other at the interval;
A tube integrated with the end plate and the plurality of fins by being inserted through the through hole of the end plate and the through holes of the plurality of fins leaving a protrusion, and being expanded;
A heat exchanger comprising:
The tube has a taper-shaped formed portion having a small diameter on the side close to the tube opening and a large diameter on the far side, and the maximum diameter portion of the taper-shaped formed portion is inherent in the protrusion of the tube, and the protrusion The heat exchanger has a length that is longer than the length from the end plate to the minimum diameter portion of the tapered molded portion .   The heat exchanger according to claim 5, wherein the tube includes a plurality of tapered forming portions in the tube axis direction.   The heat exchanger according to claim 5 or 6, wherein the tapered molded part has an elliptical cross-sectional shape. The heat exchanger according to any one of claims 5 to 7,
A compressor that compresses the refrigerant and discharges the refrigerant to the heat exchanger;
A fan for cooling the heat exchanger;
An electrical component box that supplies power to the compressor and fan and controls them;
A housing for housing the heat exchanger, compressor, fan and electrical box, a bottom plate, a top plate,
An air conditioner outdoor unit comprising:

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