Heat exchanger and pipe cap

Abstract

Provided is a heat exchanger including a joining member that can join inflow / outflow piping to the heat exchanger with high positional accuracy of a joining position without increasing the number of components and reducing the degree of freedom in designing HVAC.　Provided is a heat exchanger including a pipe cap connected to a heat medium inflow / outflow pipe, the heat exchanger being characterized by including a pair of header tanks and characterized in that: the pipe cap is provided with a first opening into which the heat medium flows and a second opening from which the heat medium flows out; cylindrical rising parts having the same height are formed in the first opening and the second opening, the direction of the central axis of the rising parts being parallel to the extending direction of the header tanks; a flange part is formed at the tip of the rising parts; and a line obtained by vertically projecting the outer edge of the flange part in the extending direction does not extend beyond the outer edge of the pipe cap excluding the flange part.

Description

Heat exchanger and pipe cap

[0001] The present invention relates to a heat exchanger and a pipe cap.

[0002] For example, as a configuration of a heat exchanger used in a vehicle air conditioner or the like, the first header tank among a pair of header tanks (first header tank, second header tank) is composed of two hollow cylindrical bodies (first hollow cylindrical body, second hollow cylindrical body) arranged in parallel, and a first core part is provided between the first hollow cylindrical body and the second header tank, and a second core part is provided between the second header tank and the second hollow cylindrical body. Such a configuration is known.

[0003] An inflow pipe for introducing a heat medium (referring to all fluids for carrying heat such as refrigerant, cooling water, etc.) is connected to one end of the first hollow cylindrical body, and an outflow pipe for discharging the heat medium is connected to one end of the second hollow cylindrical body. And heat exchange is performed between the two core parts (first core part and second core part) and a fluid (for example, air) passing orthogonally.

[0004] In such a heat exchanger, two core parts are arranged in parallel between the first header tank and the second header tank, and the heat medium flows in a U-turn between the pair of header tanks, so that it becomes a small-sized and highly efficient heat exchanger (see Patent Document 1).

[0005] The hollow cylindrical body provided in the first header tank and the inflow and outflow pipes (hereinafter, these pipes are collectively referred to as "inflow / outflow pipes") are connected via a pipe cap attached to one end of the first header tank. Hereinafter, the joining of the first header tank and the inflow / outflow pipes will be described with reference to FIGS. 5 and 6.

[0006] First, the pipe cap 100 is fitted to the first header tank 12 and fixed by caulking, and then the inflow / outflow pipe 50 is fitted and fixed by caulking. Then, it is joined by integral brazing (black arrow shown in the figure) (see FIG. 5).

[0007] Alternatively, the pipe cap 100 is first fitted onto the first header tank 12 and secured by crimping, then the short pipe 110 is fitted onto it and secured by crimping, and then integrally brazed (indicated by the black arrow in the figure). Next, the short pipe 110, which is joined to the first header tank 12 and the pipe cap 100, and the inlet and outlet piping 50 are joined by partial brazing such as torch brazing (indicated by the white arrow in the figure) (see Figure 6).

[0008] Japanese Patent Publication No. 2014-001897

[0009] Incidentally, if the position of the tip of the inlet / outlet pipe 50 deviates from its predetermined position, it may not be able to be assembled to the components (for example, the expansion valve) or piping that make up the circuit connected to the heat exchanger 1, resulting in a defective product. For this reason, high precision is required in positioning the tip of the inlet / outlet pipe 50.

[0010] In the joining method shown in Figure 5, which does not use the short pipe 110, the joining distance D1 at the joint between the first header tank 12 and the inlet / outlet piping 50 is short. Therefore, a complex brazing jig is required to fix the position of the end of the inlet / outlet piping 50 when brazing it integrally. Consequently, investment in and maintenance of the brazing jig are required. Furthermore, since the work of assembling the complex brazing jig cannot be automated, there was a problem of increased costs. In addition, depending on the layout of the inlet / outlet piping 50, the loading efficiency when transporting the heat exchanger 1 after joining the inlet / outlet piping 50 deteriorated, resulting in higher transportation costs. Moreover, because the joining distance D1 is short, it is difficult to attach the sealing member for airtightness testing of the heat exchanger 1 before integrally brazing the inlet / outlet piping 50. This resulted in the problem that airtightness testing had to be performed after integrally brazing the first header tank 12 and the inlet / outlet piping 50.

[0011] In the joining method using the short pipe 110 as shown in Figure 6, the first header tank 12 of the heat exchanger 1 and the inlet / outlet piping 50 are joined via the short pipe 110, so a sufficient joining distance D2 at the joint can be secured, and complex jigs are not required for brazing. In addition, since the inlet / outlet piping 50, which can be partially brazed later, can be removed, the heat exchanger 1 can be transported, thus eliminating problems associated with transportation.

[0012] However, the presence of the short pipe 110 increases the bending distance D3 of the inlet and outlet piping 50 from the heat exchanger 1 (the vertical distance from the heat exchanger 1's side facing the inlet and outlet piping 50 to the furthest point of the inlet and outlet piping 50). This reduces the design flexibility of the HVAC, or makes it impossible to meet the specifications required for miniaturized HVACs. In addition, it leads to increased costs and increased material management burden due to the increased number of parts.

[0013] The present invention was made to solve the aforementioned conventional technical problems, and aims to provide a heat exchanger equipped with a joining member that allows for accurate joining of inlet and outlet piping and the heat exchanger without increasing the number of parts or reducing the design flexibility of the HVAC.

[0014] To solve these problems, the heat exchanger according to the present invention has the following configuration: A heat exchanger equipped with a pipe cap connected to inlet and outlet piping for a heat transfer medium, comprising a pair of header tanks, wherein the pipe cap has a first opening for the heat transfer medium to flow in and a second opening for the heat transfer medium to flow out, the first opening and the second opening have cylindrical rising portions of equal height formed parallel to the extending direction of the header tank and the direction of the central axis, a flange portion is formed at the tip of the rising portion, and the line obtained by vertically projecting the outer edge of the flange portion along the extending direction is less than or equal to the outer edge of the pipe cap excluding the flange portion.

[0015] According to the present invention, which has these features, it is possible to join the inlet and outlet piping and the heat exchanger with high precision in the joining position without increasing the number of parts or reducing the design flexibility of the HVAC.

[0016] This is a perspective view of a heat exchanger according to an embodiment of the present invention, viewed from the upper left rear. This is a perspective view of a pipe cap according to an embodiment of the present invention, viewed from the upper left rear. This is a perspective view of a pipe cap according to an embodiment of the present invention, viewed from the upper right front. This is a top view showing the pipe cap, inlet / outlet piping, and header tank connected according to an embodiment of the present invention. This is a diagram showing a conventional method of connecting a heat exchanger and piping (without a short pipe). This is a diagram showing a conventional method of connecting a heat exchanger and piping (with a short pipe).

[0017] Embodiments of the present invention will be described below with reference to the drawings. Each drawing is illustrative of an embodiment of the present invention and is not intended to limit the invention. In the following description, the same reference numerals in different figures indicate parts with the same function, and redundant explanations in each figure will be omitted as appropriate.

[0018] In drawings, the dimensional relationships of each element are for the purpose of facilitating understanding and are not intended to restrict actual dimensional ratios.

[0019] Furthermore, in this embodiment, directions are indicated based on the X direction (front-to-back direction), Y direction (left-to-right direction), and Z direction (vertical up-and-down direction), as shown by the solid arrows in each drawing. In the following description, the positive X direction is defined as the rear direction, the negative X direction as the front direction, the positive Y direction as the right direction, the negative Y direction as the left direction, the positive Z direction as the up direction, and the negative Z direction as the down direction. The X direction (front-to-back direction) is the direction in which the fluid (e.g., air) passes from the rear (positive X direction) to the front (negative X direction) (ventilation direction), and the Y direction (left-to-right direction) is the direction in which the multiple tubes 40 are stacked.

[0020] As shown in Figure 1, the heat exchanger 1 comprises a first header tank 12 located at the top of the heat exchanger 1, a second header tank 18 located at the bottom of the heat exchanger 1, and a heat exchange core 30 formed between the first header tank 12 and the second header tank 18.

[0021] The heat exchange core 30 has a plurality of tubes 40, fins (not shown) provided between adjacent tubes 40, and a pair of side plates 20 provided at both ends in the stacking arrangement direction of the plurality of tubes 40 (Y direction shown). In the heat exchanger 1, heat exchange takes place between a heat transfer medium flowing through the tubes 40 of the heat exchange core 30 in the Z direction shown and a fluid (for example, air) passing through the heat exchange core 30 in the X direction shown.

[0022] In the example shown in Figure 1, a group of tubes 40 arranged in the Y direction is arranged in two rows in the X direction (a direction perpendicular to the stacking direction of the tubes 40).

[0023] The first header tank 12 and the second header tank 18 are hollow cylindrical structural members that extend in the direction of stacking arrangement of the multiple tubes 40 (Y direction in the figure). The first header tank 12 is provided with a partition (not shown) that divides the internal hollow portion into two regions. The partition is a plate-shaped member provided inside the first header tank 12 along the longitudinal direction (Y direction in the figure).

[0024] The interior of the first header tank 12 is divided by a partition into two regions: a first region 14 corresponding to a group of tubes 40 located in the row on the negative side in the X direction shown in the figure, and a second region 16 corresponding to a group of tubes 40 located in the row on the positive side in the X direction shown in the figure.

[0025] Multiple communication holes are formed on the heat exchange core 30 side of the first region 14 and the second region 16, which are connected to multiple tubes 40.

[0026] Alternatively, instead of being divided by a partition, two hollow cylindrical bodies may be provided inside the hollow first header tank 12, extending along the longitudinal direction (Y direction in the figure) of the first header tank 12.

[0027] A pipe cap 60 is provided at one end of the first header tank 12 in the longitudinal direction (Y direction), and a cap 90 is provided at the other end. The pipe cap 60 is provided with a first opening 72 and a second opening 74 for the inflow and outflow of the heat transfer medium (see Figure 2). The cap 90 is a closed lid without any openings. An inflow pipe 52 is connected to the first opening 72, and an outflow pipe 54 is connected to the second opening 74. In the heat exchanger 1, the heat transfer medium flows from the inflow pipe 52 through the first opening 72 into the first header tank 12, undergoes heat exchange in the heat exchange core 30, and then flows out through the second opening 74 into the outflow pipe 54.

[0028] The second header tank 18 has basically the same structure as the first header tank 12, except that both ends in the longitudinal direction (Y direction) are closed with caps 90.

[0029] As shown in Figures 2 and 3, the pipe cap 60 has two openings (first opening 72, second opening 74) for connecting the inlet and outlet pipes 50 (inlet pipe 52 and outlet pipe 54), a slit hole 62 extending in the vertical direction (Z direction) into which a protruding portion 17 (see Figure 4) provided on the partition is fitted, a flange portion 64 that covers the outer circumferential surface of the end of the first header tank 12, and a plurality of locking claws 66 that protrude from the flange portion 64 in the longitudinal direction (positive Y direction) of the first header tank 12 for locking the first header tank 12.

[0030] The vertical length of the slit hole 62 is formed to be equal to the maximum vertical length of the protruding portion 17 of the partition. This allows the protruding portion 17 and the slit hole 62 to engage without any gaps.

[0031] Furthermore, if the heat exchanger 1 is an evaporator, it is preferable to make the diameter of the outlet pipe 54 and the second opening 74 larger than the diameter of the inlet pipe 52 and the first opening 72 in order to accommodate the volume change due to the phase change of the refrigerant.

[0032] As shown in Figure 4, the pipe cap 60 has a cylindrical first riser section 82 into which the inlet pipe 52 is inserted, with its central axis A1 parallel to the extending direction of the first header tank 12. Similarly, a cylindrical second riser section 84 into which the outlet pipe 54 is inserted is formed with its central axis A2 parallel to the extending direction of the first header tank 12. The first riser section 82 and the second riser section 84 are collectively referred to as the "riser section 80".

[0033] In conventional pipe caps 100, the height of the riser portion is low, causing heat to be lost to the heat exchanger 1, making it impossible to perform proper partial brazing. In contrast, in the embodiment of the present invention, the height of the cylindrical riser portion 80 into which the inlet and outlet pipes 50 are inserted is set to a height that allows for partial brazing.

[0034] The height at which partial brazing can be performed is a predetermined range of heights based on factors such as joint strength, erosion and deformation of the heat exchanger 1 due to heating during brazing, and the reduction in height. The brazing condition can be confirmed and evaluated by, for example, inspection using X-rays or ultrasound, airtightness testing, or visual inspection.

[0035] By setting the height of the riser portion 80 of the pipe cap 60 to a height that allows for partial brazing, it becomes possible to join one end of the first header tank 12 to the inlet / outlet piping 50 as follows.

[0036] First, the pipe cap 60 is fitted onto one end of the first header tank 12, fixed by crimping, and joined by integral brazing. Next, the pipe cap 60 joined to the first header tank 12 and the inlet / outlet piping 50 are joined by partial brazing such as torch brazing.

[0037] By using the pipe cap 60 according to the present invention, partial brazing is possible. Unlike when using the conventional pipe cap 100 shown in Figure 5, the heat exchanger 1 with the pipe cap 60 attached can be transported to the first header tank 12, and then the inlet and outlet piping 50 and the heat exchanger 1 can be joined by partial brazing. This makes it possible to transport the heat exchanger 1 efficiently. Furthermore, there is no need to add parts such as the short pipe 110 shown in Figure 6 for efficient transport.

[0038] Furthermore, the height of the riser portion 80 of the pipe cap 60 according to the present invention is higher than that of the riser portion of the conventional pipe cap 100 because it allows for partial brazing. Therefore, compared to using the conventional pipe cap 100, the fixing of the inlet / outlet piping 50 and the heat exchanger 1 is more stable, making it possible to join them without using complex jigs. Also, because the riser portion is higher than that of the conventional pipe cap 100, it becomes possible to attach a sealing member for airtightness testing.

[0039] Furthermore, the rising portion 80 of the pipe cap 60 according to the present invention is a modified version of the shape of the conventional pipe cap 100, with a height that allows for partial brazing. As a result, the height of the rising portion 80 can be kept lower than the height of the joint (joint distance D2) when a conventional short pipe 110 is attached. Therefore, it is possible to improve the design flexibility of the HVAC compared to when using a conventional short pipe 110.

[0040] Furthermore, while the height of the riser portion 80 may preferably be 4 mm to 8 mm, and especially 5 mm to 7 mm, it varies depending on various factors such as the size and thickness of the pipe cap, the diameter and weight of the inflow piping, the type of brazing material, the brazing temperature, and the size of the heat exchanger. Therefore, it is impossible or impractical to uniquely determine a statistically significant value.

[0041] Next, the relationship between the height H1 of the cylindrical first upright portion 82 and the height H2 of the second upright portion 84 will be described. When the diameters of the first upright portion 82 and the second upright portion 84 are the same, the height at which partial brazing can be performed is the same for both, and as a result, they have the same height. On the other hand, for example, in the case of an evaporator where the diameters of the inflow pipe 52 and the outflow pipe 54 are different, the height H2 of the second upright portion 84 with the larger diameter is set to a height at which partial brazing can be performed, but the height H1 of the cylindrical first upright portion 82 with the smaller diameter may be made higher than the height H2 of the second upright portion 84. This is because the inflow pipe 52 has a smaller diameter and thus can have a smaller bending distance D3 than the outflow pipe 54. Therefore, due to this difference, the inflow pipe 52 has a margin in the bending distance D3 from the heat exchanger 1.

[0042] Also, when forming the pipe cap 60 by drawing, it is preferable to make the portion with the larger diameter higher in terms of reducing the working load.

[0043] However, when performing an airtight inspection to check for poor brazing of the heat exchanger 1, it is preferable that the heights H1 of the cylindrical first upright portion 82 and the height H2 of the second upright portion 84 are the same. This is because the workability of connecting a device for injecting nitrogen gas or helium gas to the pipe cap 60 during the airtight inspection is improved. Therefore, when prioritizing the airtight inspection, it is preferable to process the height H1 of the first upright portion 82 to be equal to the height H2 of the second upright portion 84.

[0044] Flanges 68 are formed at the tips of the two upright portions 80 of the pipe cap 60. By using the flanges 68, it becomes possible to easily arrange the stationary brazing material, so that brazing can be performed reliably. Also, by forming the flanges 68, they can be engaged with the jig for the airtight inspection, and it becomes possible to easily fix the jig for the airtight inspection.

[0045] The width W1 of the flange 68 is such that the line obtained by vertically projecting the outer edge of the flange along the extending direction of the central axis A1 (that is, the contour line of the flange when viewed from the negative Y direction to the positive Y direction in the drawing) does not exceed the outer edge G1 of the pipe cap 60 excluding the flange 68.

[0046] By restricting the width W1 of the flange 68, when transporting the heat exchanger 1 after attaching the pipe cap 60, it is possible to prevent the flange 68 from colliding with and damaging other members, or the flange 68 from interfering with other members and hindering transportation. Also, by setting the width W1 of the flange 68 to a predetermined length or less, it is possible to prevent the overflow outside the deposited brazing material.

[0047] Further, when viewing the pipe cap 60 from the negative Y-direction side in the drawing, that is, when vertically projecting the flange 68 along the extending direction of the central axis A1, it is preferable that the length of the slit hole 62 (the protruding portion 17 of the partition portion) of the pipe cap 60 is not hidden by the flange 68. By setting the width W1 of the flange 68 to the length where the slit hole 62 is not hidden, it becomes possible to visually confirm whether the brazing of the slit hole 62 and the partition portion in the first header tank 12 is surely performed. The minimum value of the width W1 of the flange 68 is the length where the deposited brazing material can be arranged, but like the height of the upright portion 80 described above, it depends on factors such as the type of brazing material and the size of the pipe cap 60, so it is impossible and impractical to represent it numerically.

[0048] As described above, the embodiments of the present invention have been described in detail with reference to the drawings, but the specific configuration is not limited to the above-described embodiments, and even if there are design changes and the like within the scope not departing from the gist of the present invention, they are included in the present invention.

[0049] The heat exchanger only needs to be used for the transfer and recovery of thermal energy, and is not limited to vehicles. For example, it is used in various scenarios such as air conditioners, boilers, refrigerators, and medical devices. Also, the refrigerant flowing through the heat exchanger may be a refrigerant that undergoes a phase change, or may be, for example, water that does not involve a phase change.

[0050] 1: Heat exchanger, 12: First header tank, 14: First region, 16: Second region, 17: Protrusion, 18: Second header tank, 20: Side plate, 30: Heat exchange core, 40: Tube, 50: Inlet / outlet piping, 52: Inlet piping, 54: Outlet piping, 60, 100: Pipe cap, 62: Slit hole, 64: Flange, 66: Locking claw, 68: Flange, 72: First opening, 74: Second opening, 80: Riser, 82: First riser, 84: Second riser, 90: Cap, 110: Short pipe, A1, A2: Central axis, D1, D2: Joint distance, D3: Bending distance, G1: Outer edge, H1, H2: Height, W1: Width

Claims

1. A heat exchanger comprising a pipe cap connected to inlet and outlet piping for a heat transfer medium, comprising a pair of header tanks, wherein the pipe cap has a first opening for the heat transfer medium to flow in and a second opening for the heat transfer medium to flow out, the first and second openings have cylindrical rising portions of equal height formed thereon, parallel to the extending direction of the header tank and the direction of its central axis, a flange portion formed at the tip of the rising portion, and the line obtained by vertically projecting the outer edge of the flange portion along the extending direction is less than or equal to the outer edge of the pipe cap excluding the flange portion.

2. The heat exchanger according to claim 1, characterized in that the height of the rising portion is such that partial brazing can be performed.

3. The heat exchanger according to claim 1 or 2, characterized in that the diameters of the first opening and the second opening are different.

4. A pipe cap for connecting a heat exchanger and a heat transfer medium inlet / outlet pipe, wherein the heat exchanger comprises a pair of header tanks, the pipe cap comprises a first opening for the heat transfer medium to flow in and a second opening for the heat transfer medium to flow out, the first and second openings are formed with cylindrical rising portions of equal height parallel to the extending direction of the header tank and the direction of the central axis, a flange portion is formed at the tip of the rising portion, and the line obtained by vertically projecting the outer edge of the flange portion along the extending direction is less than or equal to the outer edge of the pipe cap excluding the flange portion.

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