JP2001108388A - Method for machining header of heat exchanger, and header for heat exchanger formed thereby - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a tube insertion part to be easily formed at a circumferen tial surface of a header even if a wall thickness of the circumferential surface of the header is made thick in order to increase a strength of the header. SOLUTION: Headers 2, 3 of Serpentine type heat exchanger 1 are formed by a first step in which a rod-like member 12 is formed by either a forging work or a casting work and an insertion segment 9 is formed at the circumferential surface of the rod-like member 12, and by a second step in which a hollow segment 13 communicated with the insertion segment 9 is drilled in the rod-like member 12 by a drilling work after the first step.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a serpentine heat exchanger used, for example, as an evaporator of a vehicle air conditioner, and more particularly to a method of processing a header and a structure of the header formed by the processing method.

[0002]

2. Description of the Related Art Serpentine-type heat exchangers used in evaporators of this kind are disclosed in
As shown in Japanese Patent Application Laid-Open No. 658-658 and Japanese Utility Model Application Laid-Open No. 62-45580, a meandering tube, a corrugated fin interposed between opposing surfaces of the meandering tube, and a pair of In general, the structure is such that the tube communicates with the inside of the header by inserting the end of the tube into an insertion portion formed on the peripheral surface of the header.

On the other hand, in recent years, refrigeration cycle
CO as refrigerant_TwoThe use of
In the serpentine evaporator shown in the conventional example,
CO _TwoIncreases the pressure in the cycle by using
As a result, the end of the tube tries to widen,
Push the insertion part where the end of the header tube is inserted.
Since it is spread, the header is likely to be damaged. this
Therefore, in order to improve the pressure resistance of the header,
When the thickness is, for example, 3 mm to 3.5 mm, and the refrigerant is CO_TwoTo
It must be thicker than the evaporator header that is not used
No.

[0004]

However, when the thickness of the peripheral surface of the header is larger than the width of the tube in the lateral direction (for example, 2 mm), a tubular header is formed in advance and the peripheral surface is pressed by a press. It becomes difficult to take the conventional process of forming the insertion portion of the tube by removing.

[0005] Further, when a refrigerant inflow port is provided on the leeward side of the header, the refrigerant may concentrate on the leeward side of the header due to inertia of the refrigerant. Since heat is exchanged between the high-temperature wind and the refrigerant, the required amount of the refrigerant increases. Therefore, it is necessary to control the distribution of the refrigerant so that the refrigerant flows more on the windward side of the heat exchanger.

Therefore, in the present invention, even if the peripheral surface of the header is thickened in order to increase the strength of the header, it is possible to form a tube insertion portion on the peripheral surface, so that the refrigerant flowing in the header is located on the upstream and downstream sides. It is an object of the present invention to provide a method of processing a header of a heat exchanger that enables control of a flow rate distribution between the side and the heat exchanger, and a heat exchanger having a header formed by the processing method.

[0007]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method of processing a header of a heat exchanger, wherein a plurality of flat portions and bent portions form a serpentine shape which is sequentially continuous, and a flow path through which a refrigerant flows. Used in a heat exchanger having a tube having a tube and fins interposed between the flat portions of the tube, and provided at both ends of the tube and into which the ends of the tube are inserted. In a method for processing a header of a heat exchanger in which a portion is formed on a peripheral surface, the processing of the header forms a rod-shaped member by forging or casting, and forms the insertion portion on a peripheral surface of the rod-shaped member. A first step, and after this first step,
A second step of forming a hollow portion communicating with the insertion portion in the axial direction from the end of the rod-shaped member by drilling (claim 1). And the first
In the step, the formation of the rod-shaped member and the formation of the insertion portion on the peripheral surface of the member may be performed simultaneously.

As described above, since the tube insertion portion is first formed by forging or casting, and then the hollow portion is formed by drilling, it is not affected by the thickness of the peripheral surface of the header. Even if the entire area of the peripheral surface of the header is set to a thickness of, for example, 3 mm or 3.5 mm to increase the strength of the header because CO ₂ is used, the insertion portion can be reliably formed.

Further, in the first step, the bar-shaped member may be formed in a barrel shape whose center portion is thicker than both end portions. This is because the shape of the rod-shaped member can be freely formed by forging or casting, but by thus forming the rod-shaped member into a barrel shape, the hollow portion has a diameter from one end to the other end. Even when holes are evenly formed, the thickness of the vicinity of the central portion of the peripheral surface where the deformation force of the header is most likely to be concentrated becomes thicker, so that the strength of the header can be further increased.

Further, in the second step, the drilling of the hollow portion is performed by inserting a drill into the member in the axial direction (Claim 3).
As a drill used for drilling the hollow part of the process,
A tapered drill or a stepped drill may be used (claim 4). When drilling a hollow part by inserting these drills from one of the rod-shaped members,
The diameter of the hollow portion of the header increases from one side in the longitudinal direction to the other side. Further, when a hollow portion is formed by inserting these drills from both of the rod-shaped members, since the peripheral surface near the central portion has a shape protruding inward, the diameter near the central portion of the hollow portion is small. Therefore, the refrigerant also serves as a throttle for controlling the flow of the refrigerant to the leeward side.

The header of the heat exchanger formed through the first step and the second step has a serpentine shape in which a plurality of flat portions and bent portions are sequentially continuous, and has a tube having a flow path through which a refrigerant flows. And a fin interposed between the flat portion of the tube and the flat portion. The heat exchanger is provided at both ends of the tube, and an insertion portion into which the end of the tube is inserted has a peripheral portion. In the header of the heat exchanger formed on the surface, the header is formed in a bar shape by forging or casting, and the insertion portion is formed, and the header is connected to the insertion portion by drilling. The hollow portion is formed in the axial direction (claim 5).

[0012] The header may be such that the diameter of the hollow portion increases from one side in the axial direction to the other side. This allows the refrigerant on the refrigerant inflow side to communicate with the refrigerant inlet pipe on the side where the inner diameter of the hollow portion is large, so that more refrigerant can flow on the windward side of the heat exchanger, and the heat exchange capacity of the heat exchanger Can be improved.

The thickness of the header near the center in the axial direction may be larger than the thickness at both ends in the axial direction. By further increasing the thickness in the vicinity of the central part of the peripheral surface of the header, the pressure resistance is enhanced, and even if CO ₂ is used as the refrigerant, the header can be reliably prevented from being deformed and damaged. .

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

A serpentine type heat exchanger 1 shown in FIGS. 1 and 2 has an inflow header 2 which is disposed on one side and communicates with a refrigerant inflow pipe 3 extending to the windward side in the ventilation direction.
And an outflow side header 4 communicating with a refrigerant outflow pipe 5 disposed on the other side and extending to the leeward side in the ventilation direction, and communicating between the inflow side header 2 and the outflow side header 4 and bent. A flat tube 6 in which a portion 6a and a flat portion 6b are sequentially connected to form a serpentine shape;
It is basically composed of a corrugated fin 7 disposed between b and 6b, and is used exclusively as an evaporator. Then, the tube 6 is, as shown in FIG.
By inserting the end portion 8 into a plug-in portion 9 extending in the axial direction on the peripheral surfaces of the headers 2 and 4, it communicates with the inside of the headers 2 and 4.

The headers 2 and 4 are 3 mm to 3.5 mm.
for example, made of aluminum having a thickness of 2 mm, which is thicker than the width in the short direction of the tube 6 (for example, 2 mm), and only one of the openings in the axial direction is opened. A cap 10 having a hole 11 is mounted.

A method of forming the header 2 and the header 3 will be described. A first step of forming a rod-shaped member 12 having an insertion portion 9 on the peripheral surface shown in FIG. It comprises a second step of providing.

When the rod-shaped member 12 in the first step is formed by forging, for example, a mold 14a and a mold 14b shown in FIG. 4 are used. Among them, the mold frame 14a is formed with a recess 15 having a semicircular cross section and a vertical upright side surface, and a flat abutting portion 16 on the periphery of the recess 15.
Are formed. On the other hand, the formwork 14b is similar to the formwork 13 in that a recess 15 having a semicircular cross section and an abutting portion 16 on the periphery thereof are formed. The standing piece 17 projects vertically in the direction, and the standing piece 17 has substantially the same dimensions as the outer dimensions of the tube 6.

Then, as shown in FIG.
After arranging a material A made of, for example, aluminum between 4a and 14b, as shown in FIG. 5B, the formwork 14a and the formwork 14b are pressed with strong force until the abutting portions 16, 16 contact each other. Move in the direction of the arrow. Thereafter, the molds 14a, 1
4b is moved in the direction opposite to the arrow direction. This allows
As shown in FIG. 5C, a rod-shaped member 12 having a plug-in portion 9 and a column having the same diameter from end to end is formed.

When the rod-shaped member 12 in the first step is formed by casting, for example, a mold 17 composed of an upper mold 17a and a lower mold 17b shown in FIG. 6A is used. The upper mold 17a and the lower mold 17b of the mold 17 are joined together to form a substantially cylindrical cavity 18 having the same diameter from one end to the other end. A protrusion 19 protrudes from the side, and the outer dimension of the protrusion 19 is the same size as the tube 6. Then, as shown in FIG. 6A, for example, melted aluminum or the like is poured into the cavity 18 of the mold 17 from the direction of the arrow, and is filled in the cavity 18 as shown in FIG. 6B.
Thereafter, the mold 17 is sufficiently cooled, and the mold 17 is divided into an upper mold 17a and a lower mold 17b as shown in FIG.
Thereby, the rod-shaped member 12 having the insertion portion 9 and having the same diameter column from end to end is formed.

The second step of forming the hollow portion 13 is performed by inserting a straight drill 19 having a uniform diameter from one side in the longitudinal direction of the rod-shaped member 12 as shown in FIG. The depth of the portion 9 has such a size as to communicate with the hollow portion 13 when the hollow portion 13 is formed. The second step of the header 3 is the same as the second step of the header 2, and the shape of the hollow portion is also the same, so that the description is omitted.

According to the above, since the insertion portion 9 is formed in advance in the first step by forging or casting, it is not affected by the thickness of the peripheral surfaces of the headers 2 and 3. Moreover, the thickness of the peripheral surfaces of the headers 2 and 3 can be freely changed by using the straight drills 19 having different diameters, and the headers 2 and 3 having the peripheral surfaces of 3 mm to 3.5 mm in thickness can be formed. Needless to say, the headers 2 and 3 have the same thickness as the header when a refrigerant other than CO ₂ is used.
It is also possible to form

Although the straight drill 19 is used in the second step of forming the hollow portion 13 in the header 2, the present invention is not limited to this. For example, FIG.
As shown in (a), a tapered drill 20 whose diameter dimension increases in a tapered shape as it advances toward the base side may be used.

When the tapered drill 20 is inserted from only one of the rod-shaped members 12, the hollow portion 13 of the header 2 has a diameter as it goes from the opening side end to the other side end as shown in FIG. 8B. Is formed to be small.
Thus, by disposing the refrigerant inflow pipe 3 on the opening side, a large amount of refrigerant can be supplied to the tube 6 on the windward side of the heat exchanger 1.
The heat exchanger 1 can be circulated, and the heat exchange capacity of the heat exchanger 1 can be improved.

On the other hand, when the taper drill 20 is inserted from both sides of the rod-shaped member 12, as shown in FIG. 8C, the hollow portion 13 of the header 2 is moved from the opening side end to the central portion as shown in FIG. Since the diameter is formed to be small, the narrowest portion located in the center of the hollow portion 13 serves as a throttle for the flow of the refrigerant, and by appropriately adjusting the inner diameter of the narrowest portion, It is possible to control the distribution of the refrigerant such that a large amount of the refrigerant flows on the windward side of the heat exchanger, or the refrigerant flows evenly on the windward side and the leeward side of the heat exchanger. Moreover, the adjustment of the diameter of the narrowest portion can be performed only by exchanging the tapered drills 20 having different diameters, so that it is very simple. Further, the thickness of the central portion of the peripheral surface of the header 2 is increased, so that the strength of the header 2 can be increased.

The hollow portion of the header 3 can be formed by a taper drill 20 as shown in FIGS.
It may be formed as shown in FIG.

Further, in a second step of forming the hollow portion 13 in the header 2, a straight drill 19 and a taper drill 2 are formed.
Instead of 0, for example, as shown in FIG. 9A, a stepped stepped drill 21 having a plurality of portions having different diameters
May be used.

When the stepped drill 21 is inserted from only one of the rod-shaped members 12, the hollow portion 13 of the header 2 is sequentially connected to the large-diameter portion 13a from the opening end side as shown in FIG. This is constituted by the small diameter portion 13b. As a result, the refrigerant inflow pipe 3
Is arranged, a large amount of refrigerant can flow through the tube 6 on the windward side of the heat exchanger 1, and the heat exchange capacity of the heat exchanger 1 can be improved.

On the other hand, when the stepped drill 21 is inserted from both sides of the rod member 12, the hollow portion 13 of the header 2 has large diameter portions 13a on both sides of the opening as shown in FIG. 13a and a small-diameter portion 13b at the center. As a result, the small diameter portion 13b serves as a throttle for the flow of the refrigerant, and the small diameter portion 13b
The distribution of the refrigerant is controlled such that a large amount of the refrigerant flows on the windward side of the heat exchanger or the refrigerant flows evenly on the windward side and the leeward side of the heat exchanger by appropriately adjusting the inner diameter of the heat exchanger. Becomes possible. Moreover, the adjustment of the inner diameter of the small diameter portion 13b can be performed only by replacing the stepped drills 21 having different diameters, so that it is very simple. Further, the thickness of the central portion of the peripheral surface of the header 2 is increased, so that the strength of the header 2 can be increased.

The hollow portion of the header 3 can be formed with a step drill 21 as shown in FIGS.
It may be formed as shown in FIG.

Lastly, the shape of the rod-shaped member 12 has been described so far as a column having the same diameter from end to end. However, the shape is not necessarily limited to this, and the rod-shaped member 12 is formed by forging or casting. The degree of freedom of the shape that can be selected when forming 12 is high. Therefore, FIG.
As shown in (1), it is possible to form the rod-shaped member 12 into a substantially barrel-like shape whose center portion is the thickest. And
By using such a substantially barrel-shaped rod-shaped member 12, FIG.
By inserting a straight drill 19 shown in (a), a header 2 having a thick central portion can be formed.
Note that the header 3 can be formed in the same manner as the header 2, and the shape thereof is also the same, so that the description is omitted.

[0032]

As described above, according to the present invention,
First, a forging or casting process is used to form the insertion portion of the tube, and then a hole is formed by drilling a hollow portion.Thus, the formation of the insertion portion is not affected by the thickness of the peripheral surface of the header. Even if the peripheral surface of the header is made uniform in thickness, the insertion portion can be reliably formed because CO ₂ is used.

Further, according to the present invention, when the hollow portion of the tube is formed by drilling a hollow portion by inserting a taper drill or a stepped drill from one of the rod-shaped members, the hollow portion of the header is formed. Since the hollow portion can be formed to have a larger diameter as it advances from one side to the other side, by allowing the larger diameter portion of the hollow portion to communicate with the refrigerant inlet pipe for the header on the refrigerant inflow side, A large amount of refrigerant can flow on the windward side of the heat exchanger, and the performance of the heat exchanger can be improved.

Furthermore, according to the present invention, when a hollow portion is formed by inserting a taper drill or a stepped drill from both of the rod-shaped members when the hollow portion of the tube is pierced by a boring process, The thickness near the center of the peripheral surface becomes thicker, the pressure resistance of the header is improved, and the peripheral surface near the center has a shape protruding inward, so that the diameter near the center of the hollow becomes smaller. Since it acts as a throttle for the flow of the refrigerant to the leeward side, a large amount of refrigerant can flow on the leeward side of the heat exchanger only by changing the diameter near this central part, and the leeward side and the leeward side of the heat exchanger. It is possible to control the distribution of the refrigerant such that the refrigerant flows uniformly between the sides.

According to the present invention, the rod-shaped member is formed into a barrel shape by forging or casting, and thereafter, the hollow portion is formed to have a uniform diameter from one end to the other end. The step makes it possible to easily increase the thickness of the portion near the center of the peripheral surface of the header.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an overall configuration of a serpentine heat exchanger using a header according to the present invention.

FIG. 2 is a partial cross-sectional view illustrating a configuration of a header according to the first embodiment.

FIG. 3 is a perspective view showing a configuration of a rod-shaped member formed in a first step.

FIG. 4 is a perspective view showing a mold used when a bar-shaped member is formed by forging.

FIGS. 5A, 5B, and 5C are explanatory views showing an example of a process in a case where a rod-shaped member is formed by forging.

FIGS. 6A, 6B, and 6C are explanatory views showing an example of steps in the case of forming a rod-shaped member by casting.

FIG. 7A is an explanatory view showing a step of forming a hollow portion in a rod-shaped member using a straight drill, and FIG.
(B) is sectional drawing which shows the shape of the hollow part shape | molded by the straight drill.

FIG. 8A is an explanatory view showing a step of forming a hollow portion in a rod-shaped member using a taper drill, and FIG.
FIG. 8 (c) is a cross-sectional view showing the shape of a hollow portion formed by inserting a taper drill from one of the rod-shaped members.
FIG. 4 is a sectional view showing a shape of a hollow portion formed by inserting a taper drill from both sides of a rod-shaped member.

FIG. 9A is an explanatory view showing a step of forming a hollow portion in a rod-shaped member by using a stepped drill, and FIG.
FIG. 9C is a cross-sectional view showing the shape of a hollow portion formed by inserting a stepped drill from one of the rod-shaped members, and FIG.
FIG. 4 is a cross-sectional view showing a shape of a hollow portion formed by inserting a stepped drill from both sides of a rod-shaped member.

FIG. 10 (a) is a perspective view showing a rod-shaped member formed so that its central portion is the thickest, and FIG.
FIG. 0 (b) is a cross-sectional view showing a state where a hollow portion is formed in the rod-like member by the straight drill.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat exchanger 2 Inflow side header 4 Outflow side header 6 Tube 6a Bent part 6b Flat part 7 Fin 9 Insertion part 12 Bar-shaped member 13 Hollow part 14a Formwork 14b Formwork 17 Mold 19 Straight drill 20 Taper drill 21 Step drill

Claims (7)

[Claims] A tube having a serpentine shape in which a plurality of flat portions and bent portions are sequentially continuous, and having a flow path through which a refrigerant flows, and a fin interposed between the flat portion and the flat portion of the tube. A method for processing a header of a heat exchanger, wherein the header is provided at both ends of the tube, and an insertion portion into which the end of the tube is inserted is formed on a peripheral surface. Is a first step of forming a rod-shaped member by forging or casting and forming the insertion portion on the peripheral surface of the rod-shaped member. After the first step, the end of the rod-shaped member is formed by drilling And a second step of piercing a hollow portion communicating with the insertion portion in the axial direction from the portion. 2. The processing of the header of the heat exchanger according to claim 1, wherein, in the first step, the rod-shaped member is formed in a barrel shape in which a central portion is thicker than both end portions. Method. 3. The method for processing a header of a heat exchanger according to claim 1, wherein, in the second step, drilling of the hollow portion is performed by inserting a drill into the member in an axial direction. 4. The method for processing a header of a heat exchanger according to claim 1, wherein a taper drill or a stepped drill is used as a drill used for drilling a hollow portion in the second step. 5. A tube in which a plurality of flat portions and bent portions form a continuous serpentine shape and have a flow path through which a refrigerant flows, and a fin interposed between the flat portion and the flat portion of the tube. Used in a heat exchanger having: a heat exchanger header provided at both ends of the tube, and an insertion portion into which the end of the tube is inserted is formed on a peripheral surface, wherein the header is forged. The heat exchange is characterized in that the whole shape is formed in a rod shape by machining or casting, and the insertion portion is formed, and a hollow portion communicating with the insertion portion is formed in the axial direction by drilling. Container header. 6. The header of the heat exchanger according to claim 6, wherein the diameter of the hollow portion increases from one side in the axial direction to the other side. 7. The header of the heat exchanger according to claim 6, wherein the thickness of the header near the center in the axial direction of the peripheral surface is larger than the thickness at both ends in the axial direction.