JP2012102928A - Heat exchanger, and vehicle air conditioner including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve joint strength between header pipes forming a header tank and flat tubes and strength of the header pipes themselves, and also to achieve downsizing, reduction in weight, cost reduction and improvement in the degree of freedom in design of a heat exchanger.SOLUTION: The radial cross-sectional shape of each header pipe 7 is formed into a non-circular shape. When viewed in the axial direction of each header pipe 7, a first included angle θ1 at a surface intersection point C1 where the outer surface (surface 7c, surface 7e) of each header pipe 7 intersects with the outer surface of each flat tube 3 is set to an obtuse angle of 120° or more, and also a second included angle θ2 is set to 80-104°, the second included angle being formed by a connection line L connecting the center point C2 in the drawing of each header pipe 7 and the surface intersection C1 and the tangent T of the flat tube 3 at the surface intersection C1.

Description

  The present invention relates to a heat exchanger having improved strength at a joint between a header tank and a flat tube, and a vehicle air conditioner including the heat exchanger.

  The general structure of heat exchangers such as condensers and evaporators for vehicle air conditioners, radiators for exchanging engine cooling water, and heater cores is a parallel arrangement of a pair of left and right header tanks between these two header tanks. In addition, a plurality of flat tubes are joined in parallel with each other while being spaced apart from each other and at right angles to the header tank, and radiating fins are provided between the flat tubes.

  The header tank is formed by a header pipe formed by bending a sheet metal material or rolling it into a cylindrical shape. In Patent Document 1 below, an example (see FIGS. 1 and 2) in which a header tank is formed by a square pipe header pipe formed by bending a sheet metal material, and a round pipe shape formed by rolling a sheet metal material. An example in which a header tank is formed by a header pipe (see FIG. 6) is disclosed. Patent Document 2 below discloses an example (see FIG. 2) in which a header tank is formed of a round pipe-like header pipe.

JP 2005-114199 A JP 2006-162116 A

  However, when the header tank is formed with a header pipe formed in the shape of a square pipe, each surface of the header tank becomes flat, so that each surface tends to expand outward as the internal pressure of the heat exchanger increases. In addition, the pressure resistance is reduced and the relative angle at the intersection of the outer surface of the header tank and the outer surface of the flat tube is a right angle, that is, close to an acute angle, so the stress concentration increases and the internal pressure of the heat exchanger increases. In this case, there is a concern that this portion may lead to destruction, and in order to prevent this, the thickness of the header tank (header pipe) and the flat tube must be increased, leading to an increase in weight and an increase in cost.

  On the other hand, when the header tank is formed of a header pipe formed in a round pipe shape, the rigidity of the header tank is increased, so there is no concern about the pressure resistance described above, and the outer surface of the header tank and the outer surface of the flat tube are eliminated. Since the relative angle at the intersection is an obtuse angle, the stress concentration at this portion can be reduced. However, on the other hand, since it becomes difficult to process a curved surface or weld it, there is a problem that the manufacturing cost of the header tank increases.

  Moreover, since the header tank is circular in plan view, for example, the width of the header tank cannot be reduced to make the heat exchanger compact, and the degree of design freedom is low. In such a case, if the header tank is formed by using an elliptical pipe-shaped header pipe instead of the round pipe and arranged so that the major axis of the elliptical cross section becomes the header tank width in plan view, the horizontal width of the header tank It is possible to reduce the size of the heat exchanger. However, in this case, as in the case of the square pipe-shaped header tank, the relative angle at the intersection of the outer surface of the header tank and the outer surface of the flat tube becomes close to an acute angle.

  The present invention has been made in view of such circumstances, and improves the joint strength between the header pipe and the flat tube and the strength of the header pipe itself, as well as downsizing, weight reduction, cost reduction, and design freedom. It is an object of the present invention to provide a heat exchanger capable of improving the efficiency and a vehicle air conditioner equipped with the heat exchanger.

In order to solve the above problems, the heat exchanger of the present invention and the vehicle air conditioner equipped with the heat exchanger employ the following means.
That is, the heat exchanger according to the present invention includes a pair of parallelly arranged header pipes forming a header tank, a parallel space with a space between the header pipes, and a right angle to the header pipes. In the heat exchanger mainly composed of a plurality of flat tubes joined to the flat tubes and radiating fins attached to the flat tubes, the header pipe has a non-circular sectional shape in the radial direction, and the header pipe is viewed in the axial direction. A first connecting angle at the surface intersection where the outer surface of the header pipe and the outer surface of the flat tube intersect, and a connecting line connecting the centroid of the header pipe and the surface intersection; The second sandwiching angle formed by the tangent line of the flat tube at the surface intersection is set to 80 ° or more and 104 ° or less.

  According to the inventors' experimental analysis, as described above, the first sandwich angle at the surface intersection where the outer surface of the header pipe and the outer surface of the flat tube intersect is obtuse, and the centroid of the header pipe When the second sandwich angle between the connecting line connecting the surface intersection and the tangent of the flat tube at the surface intersection is set to 104 ° or less, the joint strength between the header pipe and the flat tube should be higher than the target value. Can do. The smaller the second sandwiching angle is, the more the joint strength can be improved. However, when the angle is 80 ° or less, the header pipe and the flat tube interfere with each other. For this reason, by setting the second sandwiching angle to 80 ° or more and 104 ° or less, the header pipe and the flat tube can have the highest joint strength without using a round pipe as the header pipe, and the header Interference between the pipe and the flat tube can be prevented.

  Thus, a header tank can be formed without using a round pipe-shaped header pipe, and the manufacturing cost of the heat exchanger can be reduced. Moreover, since the cross-sectional shape of the header tank can be formed in a shape other than a circular shape, the design flexibility of the heat exchanger is greatly improved.

  The said structure WHEREIN: You may make it the dimension in the direction along the longitudinal direction of the said flat tube make the dimension in the radial direction cross section of the said header pipe shorter than the dimension of the direction orthogonal to the longitudinal direction of the said flat tube. In such a case, it is possible to reduce the width of the header pipe and reduce the size and weight of the heat exchanger. By doing so, the amount of the heat-dissipating liquid stored in the header tank is greatly reduced, and the effect of reducing the weight of the entire heat exchanger is high.

  Moreover, in the said structure, it is preferable to form the said header pipe by joining two pipe half bodies which radial cross-sectional shape makes a substantially U shape in the direction which mutually opposes. According to this configuration, since the header pipe (header tank) can be formed by molding the sheet metal material without using the pipe material, the cost of the heat exchanger can be reduced.

  Furthermore, in the above configuration, the header pipe is preferably a polygonal cross-section pipe. In this way, the rigidity of the header tank can be increased.

  In the above configuration, the header pipe which is a polygonal cross-section pipe may have an R-shaped cross section in which the surface having the surface intersection point is curved radially outward or inward in the radial cross section. Thereby, while improving the rigidity of a header pipe, the joint strength of a header pipe and a flat tube can be improved.

  In the above configuration, the pipe half may be an inner pipe half to which the flat tube is fixed and an outer pipe half joined to the outside of the inner pipe half. With this configuration, it is easy to form an opening (slit hole) for inserting a flat tube in the inner pipe half, and the joining operation of the inner pipe half and the flat tube can be facilitated.

  Further, in the above configuration, the outer pipe half has a pair of joining margins joined inside a pair of joining margins of the inner pipe half, and the joining margin of the outer pipe half includes the flattening. A notch is provided to avoid interference with the tube. Thereby, the header tank can be reduced in size particularly in the width direction, and the heat exchanger can be reduced in weight.

  And the vehicle air conditioner which concerns on this invention was equipped with the heat exchanger of said each structure, It is characterized by the above-mentioned. As a result, a heat exchanger that is fragile due to vehicle vibration, heat, wind and rain, etc. can be firmly formed, and it can contribute to weight reduction and cost reduction.

  As described above, according to the heat exchanger according to the present invention and the vehicle air conditioner including the heat exchanger, the joint strength between the header pipe and the flat tube constituting the heat exchanger and the strength of the header pipe itself are improved. It is possible to reduce the size, weight, and cost.

It is an external appearance perspective view which shows the capacitor | condenser which is an example of the heat exchanger which can apply this invention. It is a perspective view which shows the structural example of the header tank of the capacitor | condenser shown in FIG. It is a horizontal longitudinal cross-sectional view in the junction part of a header pipe and a flat tube which shows 1st Embodiment of this invention. It is a figure which shows the relationship between the pinching angle which the connecting line which connects the centroid point of a header pipe and a surface intersection, and the tangent of the flat tube in a surface intersection, and a breaking pressure by a graph. It is a horizontal longitudinal cross-sectional view in the junction part of a header pipe and a flat tube which shows 2nd Embodiment of this invention. It is a horizontal longitudinal cross-sectional view in the junction part of a header pipe and a flat tube which shows 3rd Embodiment of this invention. It is a perspective sectional view in the joined part of a header pipe and a flat tube which shows a 4th embodiment of the present invention. It is a horizontal longitudinal cross-sectional view in the junction part of a header pipe and a flat tube which shows 4th Embodiment of this invention.

  Hereinafter, a plurality of embodiments of a heat exchanger according to the present invention will be described with reference to FIGS. In the following description, an example in which the present invention is applied to a capacitor of a vehicle air conditioner will be described as an example of a heat exchanger.

[First Embodiment]
FIG. 1 is an external perspective view showing a capacitor according to a first embodiment of the present invention. The capacitor 1 has a general layout, and connects a pair of left and right header tanks 2L and 2R extending in the vertical direction, and the header tanks 2L and 2R, and keeps a vertical distance from each other in parallel. In addition, a plurality of flat tubes 3 joined at right angles to the header tanks 2L and 2R and corrugated radiating fins 4 attached to the flat tubes 3 are mainly configured. These members are made of, for example, an aluminum-based material with good thermal conductivity.

  As shown in FIG. 2, the header tanks 2L and 2R are pressure tanks configured by hermetically closing the upper and lower openings of the header pipe 7 with end plates 8, and the header tanks 2L and 2R are opposed to each other. A large number of slit holes 9 into which the flat tube 3 is inserted are formed in the surface (inner surface). The ends of the flat tubes 3 are inserted into these slit holes 9 and fixed by a joining means such as brazing, and the airtightness between the slit holes 9 and the flat tubes 3 is maintained, and at the same time, the capacitor 1 Strength is secured. The internal space of the header tanks 2L, 2R is partitioned into several upper and lower rooms by a plurality of partition plates (not shown).

  For example, the header tank 2L is provided with an inflow port 11 at the lower part and an outflow port 12 at the upper part. A high pressure hose connected to the compressor (not shown) side is connected to the inflow port 11, and a low pressure hose connected to the compressor (not shown) side is connected to the outflow port 12. The header tank 2R is integrally provided with a receiver 13 incorporating a dryer and a strainer. However, the receiver 13 may be provided separately from the capacitor 1.

  The refrigerant is compressed by the compressor and then condensed by the condenser, becomes a liquid phase, flows into the lower chamber of the header tank 2L from the inflow port 11, passes through the flat tube 3, and moves from the lower chamber to the middle chamber of the header tank 2R. , And again flows into the middle chamber of the header tank 2L through the flat tube 3, and thus moves back and forth between the two header tanks 2L and 2R and finally flows out from the outflow port 12.

  The refrigerant is vaporized inside an evaporator (not shown) to form a gas phase, thereby removing the heat of vaporization to cool the evaporator, and the air blown by a blower fan (not shown) is cooled by passing through the evaporator to be cooled inside the vehicle. Sent to. Since the refrigerant flows into the capacitor 1 in a state compressed to 10 atm or more by the compressor, the capacitor 1 is required to have high airtightness and pressure resistance.

  FIG. 3 is a horizontal and vertical cross-sectional view at the joint between the header pipe 7 and the flat tube 3. As shown here, the header pipe 7 includes an inner pipe half 7A having a substantially U-shaped (or substantially C-shaped) radial cross-sectional shape, and a substantially U-shaped (joint to the outside of the inner pipe half 7A). A substantially pipe-shaped outer pipe half 7B is joined to each other in a direction facing each other by a joining means such as brazing. The slit hole 9 into which the flat tube 3 is inserted is formed in the inner pipe half body 7A, and a pair of joint margins 16 of the outer pipe half body 7B are provided inside the pair of joint margins 15 of the inner pipe half body 7A. It is a structure to be joined.

  The header pipe 7 has a non-circular cross-sectional shape in the radial direction, and is formed in a polygonal cross-section pipe shape having, for example, six surfaces 7a, 7b, 7c, 7d, 7e, and 7f. The vertical and horizontal dimensions are set such that the Y dimension in the direction along the longitudinal direction of the flat tube 3 is shorter than the X dimension in the direction orthogonal to the longitudinal direction of the flat tube 3. Of course, the width dimension of the flat tube 3 is smaller than the X dimension. The front surface 7b and the rear surface 7f of the header pipe 7 are parallel to each other, and the outer surface 7a and the inner surface 7d are gently swelled outward. It is curved. The 7c surface and the 7e surface are flat surfaces.

  In the present invention, when the header pipe 7 is viewed in the axial direction, the sandwiching angle θ1 (first sandwiching angle) at the surface intersection C1 where the outer surface (7c surface, 7e surface) of the header pipe 7 and the outer surface of the flat tube 3 intersect. ) Is an obtuse angle of 120 ° or more. Further, a connecting line L connecting the centroid point C2 of the header pipe 7, that is, a point where a vertical line passing through a half position of the X dimension and a horizontal line passing through a half position of the Y dimension intersect the surface intersection C1. Assuming that the connecting pipe L and the tangent line T2 of the flat tube 3 at the surface intersection C1 are set at 80 ° to 104 ° so that the nip angle θ2 (second nip angle) is 80 ° to 104 °. 7 and the position of the surface intersection C1 are set. In the present embodiment, the surface intersection C1 is located on the 7c surface and the 7e surface of the header pipe 7, and the sandwiching angle θ2 is 90 °.

  In this way, the sandwiching angle θ1 at the surface intersection C1 where the outer surface (7c surface, 7e surface) of the header pipe 7 and the outer surface of the flat tube 3 intersect is made an obtuse angle of 120 ° or more, and the centroid of the header pipe 7 When the sandwiching angle θ2 formed by the connecting line L connecting the point C2 and the surface intersection C1 and the tangent line T of the flat tube 3 at the surface intersection C1 is set to 104 ° or less, the joint strength between the header pipe 7 and the flat tube 3 Can be increased.

  FIG. 4 is a graph showing the relationship between the breaking pressure and the sandwiching angle θ2 formed by the connecting line L connecting the centroid C2 of the header pipe 7 and the surface intersection C1 and the tangent T of the flat tube 3 at the surface intersection C1. FIG. As shown in this graph, the present inventors have changed the target value of the breaking pressure at the surface intersection C1 to 1.00 and the sandwiching angle θ2 in the range of 80 ° to 110 ° in the capacitor 1 having the above shape. In addition, we analyzed the pressure at which the sign of destruction actually occurs at each angle. As a result, it was clarified that the target value of 1.00 was achieved when the sandwiching angle θ2 was 104 °, and that thereafter, as the sandwiching angle θ2 narrowed, the bonding strength increased and the fracture pressure increased.

  As described above, as the sandwiching angle θ2 decreases from 104 °, the joint strength between the header pipe 7 and the flat tube 3 can be improved. However, when the sandwiching angle θ2 is 80 ° or less, the outer side constituting the header pipe 7 is increased. Interference between the pipe half 7B and the flat tube 3 occurs. Therefore, by setting the sandwiching angle θ2 to 80 ° or more and 104 ° or less, the joint strength between the header pipe 7 and the flat tube 3 is set to the highest range without using a round pipe as the header pipe 7. Interference between the header pipe 7 and the flat tube 3 can be prevented.

  By configuring the capacitor 1 as described above, the header tanks 2L and 2R can be formed without using a round pipe-shaped header pipe, and thus the manufacturing cost of the capacitor 1 can be reduced. In addition, since the cross-sectional shape of the header tanks 2L and 2R can be formed in a shape other than a circular shape, the design freedom of the capacitor 1 can be improved. In particular, in this embodiment, since the header pipe 7 is formed in a polygonal cross-section pipe shape, the rigidity of the header tanks 2L and 2R can be significantly increased.

  Moreover, since the Y dimension in the radial cross section of the header pipe 7 is set shorter than the X dimension, the horizontal width of the header pipe 7 is narrowed to reduce the size and weight of the capacitor 1 and install it in the vehicle air conditioner. Can be made easier. By doing so, the amount of refrigerant stored in the header tanks 2L, 2R can be greatly reduced, and the weight reduction effect of the capacitor 1 as a whole is high.

  The header pipe 7 is formed by joining an inner pipe half 7A having a substantially U-shaped radial cross section and an outer pipe half 7B having a substantially U shape joined to the outside of the inner pipe half 7A. Therefore, the header pipe 7 (header tanks 2L and 2R) can be formed by molding a sheet metal material without using a pipe material. For this reason, the manufacturing cost of the capacitor 1 can be reduced.

  Moreover, by forming the header pipe 7 by joining the inner pipe half 7A and the outer pipe half 7B, the slit hole 9 for inserting the flat tube 3 can be easily formed in the inner pipe half 7A. it can. That is, if the processing order is such that the slit hole 9 is processed and formed in the flat plate material before being bent and then bent to complete the inner pipe half body 7A, the slit hole 9 can be easily formed. Further, since the flat tube 3 can be joined to the slit hole 9 of the inner pipe half 7A before joining the inner pipe half 7A and the outer pipe half 7B, joining of the flat tube 3 by brazing or the like is possible. Work can be facilitated.

[Second Embodiment]
FIG. 5 is a horizontal and vertical cross-sectional view of the joint portion between the header pipe 7 and the flat tube 3 showing the second embodiment of the present invention. The capacitor 21 shown in FIG. 5 has the same configuration as that of the capacitor 1 shown in the first embodiment except that the header pipe 7 has a slightly different cross-sectional shape. To do.

  In this capacitor 21, a surface having a surface intersection C1 intersecting with the outer surface of the flat tube 3 in the header pipe 7 which is a polygonal cross-section pipe, that is, the 7c surface and the 7e surface are curved so as to bulge radially outward. It has a cross section. Thus, by making the 7c surface and the 7e surface having the surface intersection C1 into an R-shaped cross section that bulges outward, the rigidity of the header pipe 7 can be increased and the bonding strength between the header pipe 7 and the flat tube 3 can be increased. it can.

[Third Embodiment]
FIG. 6 is a horizontal and vertical cross-sectional view of the joint portion between the header pipe 7 and the flat tube 3 showing the third embodiment of the present invention. The capacitor 31 shown in FIG. 6 has the same configuration as the capacitor 1 shown in the first embodiment except that the header pipe 7 has a slightly different cross-sectional shape. To do.

  In this capacitor 31, a surface having a surface intersection C1 intersecting the outer surface of the flat tube 3 in the header pipe 7 which is a polygonal cross-section pipe, that is, the 7c surface and the 7e surface are curved so as to be recessed inward in the radial direction. It has a cross section. By doing in this way, like the case of 3rd Embodiment, while improving the rigidity of the header pipe 7, the joining strength of the header pipe 7 and the flat tube 3 can be raised.

  In particular, in this capacitor 31, compared to the capacitors 1 and 21 of the first and second embodiments, the surface where the outer surface (7c surface, 7e surface) of the header pipe 7 and the outer surface of the flat tube 3 intersect. The pinching angle θ1 at the intersection C1 can be increased, and the pinching formed by the connecting line L connecting the centroid C2 of the header pipe 7 and the surface intersection C1 and the tangent T of the flat tube 3 at the surface intersection C1. Since the angle θ2 can be reduced, the joint strength between the header pipe 7 and the flat tube 3 can be increased.

[Fourth Embodiment]
FIG. 7 is a perspective cross-sectional view of a joint portion between the header pipe 7 and the flat tube 3 showing a fourth embodiment of the present invention, and FIG. 8 is a horizontal and vertical cross-sectional view of the joint portion. The capacitor 41 shown in FIG. 7 and FIG. 8 is the same as the capacitor 41 except that a cutout portion 42 that avoids interference with the flat tube 3 is provided at the joining margin 16 of the outer pipe half 7B that forms the header pipe 7. Since it is the same composition as capacitor 1 shown in one embodiment, the same numerals are given to each part and explanation is omitted.

  As described above, the notch 42 for avoiding interference with the flat tube 3 is provided in the joining margin 16 of the outer pipe half 7B, so that the outer pipe half can be reduced even if the X dimension and the Y dimension of the header pipe 7 are reduced. It can prevent that the front-end | tip part of the flat tube 3 interferes with the joining margin 16 of the body 7B. Thereby, the X dimension and Y dimension of the header tanks 2L and 2R can be made compact, and the capacitor 41 can be reduced in weight.

  And by using the capacitors 1-41 configured as described above for the vehicle air conditioner, it is possible to form a durable capacitor that is easily broken by vehicle vibration, heat, wind and rain, etc., and contribute to weight reduction and cost reduction. Can do. Needless to say, the technical scope of the present invention is not limited to the aspects of the above-described embodiments, and for example, the aspects of the embodiments may be combined. Further, the present invention can be applied not only to the condenser but also to various heat exchangers such as an evaporator, a radiator, an oil cooler, an intercooler, and a heater core.

1, 21, 31, 41 Condenser (Heat exchanger)
2L, 2R Header tank 3 Flat tube 4 Radiation fin 7 Header pipe 7A Inner pipe half 7B Outer pipe half 15 Inner pipe half joining margin 16 Outer pipe half joining margin 42 Notch C1 Surface intersection C2 Header pipe intersection Center of centroid L Connection line T Tangent line X Dimension in the direction perpendicular to the flat tube longitudinal direction of the header pipe Y Dimension in the direction along the flat tube longitudinal direction of the header pipe θ1 Pinch angle (first pinch angle)
θ2 sandwich angle (second sandwich angle)

Claims (8)

A pair of header pipes arranged in parallel to form a header tank, a plurality of flat tubes joined in parallel to each other at a right angle to the header pipe, and spaced apart from each other; In a heat exchanger configured mainly with radiating fins attached to a flat tube,
The header pipe has a non-circular cross-sectional shape in the radial direction, and the first sandwich angle at the surface intersection where the outer surface of the header pipe and the outer surface of the flat tube intersect is an obtuse angle when the header pipe is viewed in the axial direction. In addition, the second sandwiching angle formed by the connecting line connecting the centroid of the header pipe and the surface intersection and the tangent to the flat tube at the surface intersection is set to 80 ° to 104 °. Heat exchanger.   The dimension in the radial cross section of the header pipe is such that a dimension in a direction along the longitudinal direction of the flat tube is shorter than a dimension in a direction perpendicular to the longitudinal direction of the flat tube. Heat exchanger.   The heat exchanger according to claim 1 or 2, wherein the header pipe is formed by joining two pipe halves having a substantially U-shaped radial cross-section so as to face each other. .   The heat exchanger according to claim 3, wherein the header pipe is a polygonal cross-section pipe.   5. The heat according to claim 4, wherein the header pipe which is a polygonal cross-section pipe has an R-shaped cross section in which a surface having the surface intersection is curved radially outward or inward in a radial cross section thereof. Exchanger.   6. The pipe half according to claim 3, wherein the pipe half is an inner pipe half to which the flat tube is fixed and an outer pipe half joined to the outside of the inner pipe half. The described heat exchanger.   The outer pipe half is joined to the inside of the pair of joints of the inner pipe half, and the joint of the outer pipe half avoids interference with the flat tube. The heat exchanger according to claim 6, wherein a notch is provided.   The vehicle air conditioner provided with the heat exchanger in any one of Claim 1 to 7.

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