US20160238329A1

US20160238329A1 - Heat exchanger

Info

Publication number: US20160238329A1
Application number: US15/022,754
Authority: US
Inventors: Masashi UTSUNOMIYA; Osamu Hakamata
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2013-09-20
Filing date: 2014-09-17
Publication date: 2016-08-18
Also published as: JP2015059732A; WO2015040857A1

Abstract

In a heat exchanger for a vehicle, a cover member covers an upstream side end that is a part of an outer peripheral surface of a tube in which a heat medium flows, on the upstream side of the air flow. Further, the cover member is fixed to the upstream side end of the tube. For example, a width of the cover member is equal to or less than that of the tube in a direction perpendicular to the air flow direction and a flow direction of the heat medium. Thus, the heat exchanger can prevent the misalignment of the cover member with respect to the tube, thereby protecting the tube by the cover member at the front side of the vehicle. Therefore, the tube can be protected from chipping.

Description

CROSS REFERENCE TO RELATED APPLICATION

The application is based on a Japanese Patent Application No. 2013-195507 filed on Sep. 20, 2013, the contents of which are incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present disclosure relates to a heat exchanger with tubes for heat exchange.

BACKGROUND ART

Conventionally, there are known heat exchangers with tubes for heat exchange. For example, a heat exchanger disclosed in Patent Document 1 includes a plurality of tubes and fins that promote heat exchange. In the heat exchanger, liquid adhesive is charged into gaps between the tube and the fin. That is, the fins are fixed to the tubes with the adhesive.

PRIOR ART LIST

Patent Document

[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2009-36428

SUMMARY OF INVENTION

The inventors of the present application have found through their studies that in a heat exchanger with tubes for heat exchanger, like the heat exchanger described in Patent Document 1, fine solids are caught in and mixed into air flowing around the tubes of the heat exchanger to fly toward the tubes, and then hit the tubes in some cases. For example, when the heat exchanger is mounted within an engine room of a vehicle, solids, such as small stones, thrown up by traveling of the vehicle collide with the tubes of the heat exchanger, disadvantageously causing damage to the tube.
To solve the disadvantage described above, the inventors have proposed that a protective member designed to protect the tube is provided on the upstream side of air flow, exclusively to which solids fly to come, with respect to the tube. However, the protective member needs to protect the tube while not interfering with the air flow flowing into the surroundings of the tube as much as possible. Thus, it is necessary to position the protective member without misaligning it with respect to the tube.
In view of the above matter, it is an object of the present disclosure to provide a heat exchanger that can protect tubes at the front side of a vehicle by a protective member while preventing the protective member from becoming misaligned with respect to the tube.
Further, it is another object of the present disclosure to provide a heat exchanger that can protect tubes from solids flying toward the tubes by a protective member while preventing the protective member from becoming misaligned with respect to the tube.
A heat exchanger according to a first aspect of the present disclosure includes: a tube that allows a heat medium flowing therein to exchange heat with air flowing around the tube, and has an upstream side end on an upstream side of an air flow; and a protective member covering the upstream side end and being fixed to the upstream side end of the tube. The protective member is configured to protect the tube from a solid flying to the tube.
The protective member for protecting each tube from solids that are flying toward the tube is fixed to the upstream side end of the tube while covering the upstream side end, so that the protective member can be prevented from becoming misaligned with respect to the tube. Further, the protective member can protect the tube from solids that are flying toward the tube in a vehicle or the like, on the side of the tube exclusively to which solids fly to come, that is, on the upstream side of air flow on which the side end of the tube on the upstream side is positioned.
A heat exchanger for a vehicle according to a second aspect of the present disclosure includes: a core portion including a plurality of tubes, each of the tubes allowing a heat medium to flow through therein, and fins disposed on both sides of each of the tubes, the core portion being configured to exchange heat between the heat medium and air; a tank portion connected to an end in a longitudinal direction of the tube; and a protective member fixed to an upstream end of at least a part of the plurality of tubes on an upstream side of an air flow. The protective member is disposed at a front side of the vehicle with respect to the tube.
For example, the protective member may be formed by solidifying a fluid material having fluidity. Further, the tubes may be arranged, for example, to have their longitudinal directions in parallel to the vehicle width direction. The protective member may be fixed to the end of the tube on the upstream side of the air flow, in a lower part of the core portion.
For example, the protective member may be fixed to a part of the tube in the longitudinal direction. The fin may protrude toward the upstream side of the air flow with respect to the tube.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an entire structural diagram of a heat exchanger according to a first embodiment.

FIG. 2 is a cross-sectional view taken along the line II-II in FIG. 1.

FIG. 3 is a diagram for explaining a step of fixing a cover member to a side end of each tube on the upstream side in a manufacturing procedure for the heat exchanger shown in FIG. 1.

FIG. 4 is an enlarged perspective view of an IV part shown in FIG. 3.

FIG. 5 is a diagram illustrating the features of a heat exchanger according to a second embodiment, which corresponds to the section taken along the line II-II of FIG. 1.

FIG. 6 is a diagram showing a first modified example of the section of a tube, which corresponds to FIG. 2.

FIG. 7 is a diagram showing a second modified example of the section of a tube, which corresponds to FIG. 2.

FIG. 8 is a diagram showing a first modified example of the positions of formation of the cover members in the heat exchanger, which corresponds to FIG. 1.

FIG. 9 is a diagram showing a second modified example of the position of formation of the cover member in the heat exchanger, which corresponds to FIG. 1.

DESCRIPTION OF EMBODIMENTS

In the following, preferred embodiments of the present disclosure will be described with reference to the accompanying drawings. The mutually same or equivalent parts in the respective embodiments below are indicated by the same reference characters throughout the figures.

First Embodiment

FIG. 1 shows an entire structural diagram of a heat exchanger 10 in a first embodiment of the present disclosure. FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1. The heat exchanger 10 shown in FIG. 1 is mounted outside a vehicle compartment in a vehicle, specifically, in an engine room. The heat exchanger 10 exchanges heat between the outside air and an engine coolant that cools the engine, thereby dissipating heat of the engine coolant into the outside air. That is, the heat exchanger 10 is a heat exchanger for a vehicle, and the engine coolant is used as a heat medium. The coolant is allowed to circulate through the heat exchanger 10, for example, by an electric water pump (not shown).
In FIG. 1, an arrow DR1 represents the vertical direction of the vehicle with the heat exchanger 10, that is, a vehicle up-and-down direction DR1, with the upper side of FIG. 1 corresponding to the upper side of the vehicle. In this embodiment, the vehicle up-and-down direction DR1 corresponds to the arrangement direction of tubes. An arrow DR2 represents the lateral direction of the vehicle, that is, a vehicle width direction DR2. In this embodiment, the vehicle width direction DR2 corresponds to the tube longitudinal direction in which each tube 12 extends. Further, an arrow DR3 shown in FIG. 2 represents the longitudinal direction of the vehicle, that is, a vehicle front-and-rear direction DR3 with the left side of FIG. 2 corresponding to the front side of the vehicle. The vehicle up-and-down direction DR1, the vehicle width direction DR2, and the vehicle front-and-rear direction DR3 are perpendicular to one another.
As shown in FIGS. 1 and 2, the heat exchanger 10 includes a core portion 16 including a plurality of tubes 12 and fins 14, and a pair of first and second header tanks 18 and 20 that are assembled to both ends of the core portion 16.
Each of the plurality of tubes 12 has an outer peripheral surface 121 forming the outer peripheral surface of the tube 12, and allows air, or the outside air to flow around the outer peripheral surface 121. In the tube 12, the engine coolant as a fluid for heat exchange that exchanges heat with the outside air flows through the tube 12. The tube 12 is a pipe that is made of an aluminum alloy and extends linearly in the vehicle width direction DR2. The engine coolant flows through the tubes 12 in the vehicle width direction DR2, while the outside air flows from the front side to the rear side of the vehicle along the vehicle front-and-rear direction DR3.
As shown in FIG. 2, the section of the tube 12 perpendicular to the flow direction of the engine coolant, or the vehicle width direction DR2 has a flat shape that extends in the vehicle front-and-rear direction DR3 as the air flowing direction. As shown in FIG. 1, the plurality of tubes 12 are stacked in the vehicle up-and-down direction DR1 perpendicular to the air flow direction, and arranged in parallel with each other.
Each fin 14 includes a thin film made of an aluminum alloy, and molded in the form of wave as viewed from the vehicle front-and-rear direction DR3. The fin 14 is bonded to the flat surfaces of the tube 12 on both sides, for example, by brazing and the like. Such fins 14 serve to promote heat exchange between the engine coolant circulating through the tubes 12 and the air as the external fluid by increasing a heat transfer area with the air. Referring to FIG. 2, the width of the fin 14 in the vehicle front-and-rear direction DR3 is set equal to or slightly larger than that of the tube 12.
The first header tank 18 shown in FIG. 1 is connected to one end of each of all tubes 12, and has a shape that extends in the lamination direction of the tubes 12, that is, in the vehicle up-and-down direction DR1. The first header tank 18 has an internal space formed therein, which communicates with all tubes 12. The first header tank 18 includes an inlet 181 into which the engine coolant flows.
The second header tank 20 is symmetrically structured with respect to the first header tank 18 with the core portion 16 sandwiched between the header tanks. Specifically, the second header tank 20 is connected to the other end of each of all tubes 12, and has a shape that extends in the vehicle up-and-down direction DR1. The second header tank 20 has an internal space formed therein, which communicates with all tubes 12. The second header tank 20 includes an outlet 201 from which the engine coolant flows.
The heat exchanger 10 is configured in the way described above, whereby the engine coolant flowing from the inlet 181 into the first header tank 18 is distributed by the first header tank 18 to the respective tubes 12. The distributed engine coolants flow through the respective tubes 12 from the side of the first header tank 18 to the side of the second header tank 20 and are collected together at the second header tank 20. The collected coolant flows out of the outlet 201 toward the outside of the heat exchanger 10.
As shown in FIGS. 1 and 2, the heat exchanger 10 includes a plurality of cover members 22. The cover member 22 is a protective member that serves to protect the tube 12 from solids, such as small stones, thrown up by traveling of the vehicle. In detail, the cover member 22 is the protective member that has such a thickness that can protect the tubes 12 from the solids. Since the solids tend to fly from the upstream side of the air flow, or the front side of the vehicle to reach the heat exchanger 10, each cover member 22 is formed to cover a part 121 a on the upstream side of the air flow, that is, the upstream side end 121 a of the outer peripheral surface 121 of the corresponding tube 12. In short, the cover members 22 are positioned at the front side of the vehicle with respect to the tubes 12. Each cover member 22 is fixed to the upstream side end 121 a of the corresponding tube 12, for example, by bonding and the like.
In the lamination direction of the tubes 12, that is, in the vehicle up-and-down direction DR1, the width of the cover member 22 is set equal to or slightly smaller than the minor axis as the width of the flat-shaped tube 12 such that the cover member does not interfere with introduction of the outside air into between the adjacent tubes 12 as much as possible. As illustrated in FIG. 2, a tip end 22 a of the cover member 22 on the upstream side of the air flow is rounded.
The cover member 22 includes resin, or polymer material, such as acrylic resin, silicon resin, a resin containing a volatile solvent, a thermosetting resin, and an UV curing resin. For example, the cover members 22 are formed as illustrated in FIGS. 3 and 4. FIG. 3 is a diagram for explaining a step of fixing the cover members 22 to the upstream side ends 121 a of the tubes 12 (see FIG. 2) when viewing the heat exchanger 10 from the same direction as that in FIG. 1. FIG. 4 is an enlarged perspective view of an IV part shown in FIG. 3.
First, to form the cover members 22, in a first step, a resin material 221 for the cover member 22 is prepared. The resin material includes, for example, a liquid resin having a high viscosity, is prepared. The resin material 221 is a material serving as, for example, an adhesive. In the following second step, as shown in FIGS. 3 and 4, the resin material 221 for the cover member 22, that is, the fluid material 221 having fluidity is applied onto the upstream side end 121 a of each tube 12 of the core portion 16 across the entire length of the tube 12 (see FIG. 2). At this time, for example, a dispenser nozzle 26 is used. The dispenser nozzle 26 is fed in the longitudinal direction of the tube 12 as indicated by the arrow ARs of FIG. 4, while pouring the resin material 221 from the dispenser nozzle 26. The amount of outflow of the resin material 221 from the dispenser nozzle 26 and the feeding rate of the dispenser nozzle 26 are adjusted such that the cover member 22 formed over the upstream side end 121 a has an appropriate thickness that is previously determined experimentally to protect the tube 12 from chipping. In this embodiment, the cover members 22 are formed for all the tubes 12.
In a next third step, the resin materials 221 applied over the upstream side ends 121 a of the tubes 12 are solidified. Thus, the cover members 22 are completed. In the third step, to promote the solidification of the resin material 221, the resin materials 221 are heated as needed.
As mentioned above, in this embodiment, each of the cover members 22 is fixed to the upstream side end 121 a, which is a part of the outer peripheral surface 121 of the tube 12 on the upstream side of the air flow, while covering the upstream side ends 121 a. Thus, the cover members 22 are less likely to be misaligned with the tubes 12, and can protect the tubes 12 from solids on the upstream side of the air flow, exclusively to which solids fly to come, that is, at the vehicle front side. In short, the tubes 12 can be protected from chipping.
In this embodiment, as shown in FIG. 2, the tip end 22 a of the cover member 22 is formed to be rounded at the section of the cover member 22 as viewed from the flow direction of the engine coolant, which can easily introduce the outside air into a gap between the tubes 12, that is, a gap where the fin 14 is installed.
Further, in this embodiment, the width of the cover member 22 in the lamination direction of the tubes 12 is set equal to or less than the width of the tube 12, making it difficult to interfere with the introduction of the outside air into the gap between the tubes 12 without narrowing the gap between the tubes 12 as viewed from the front side of the vehicle.
In this embodiment, the cover members 22 are formed by applying and solidifying the fluid resin material 221 onto the upstream side ends 121 a of the tubes 12, so that the cover members 22 can be configured as separate members from the tubes 12. Thus, if the cover member 22 is damaged, for example, has any crack or the like, the damage is less likely to be transferred to the tubes 12, which is a merit of this embodiment. The structures of the tube 12 and fin 14 do not need to be modified, compared to a structure without having the cover member 22.

Second Embodiment

Next, a second embodiment of the present disclosure will be described. In this embodiment, a different point from the above-mentioned first embodiment will be mainly described, and the description of the same or equivalent parts as those of the first embodiments will be omitted or simplified below.
FIG. 5 illustrates a diagram of the features of a heat exchanger 10 of this embodiment, which corresponds to the section taken along the line II-II of FIG. 1 described above. That is, FIG. 5 is a diagram of this embodiment corresponding to FIG. 2 of the first embodiment. The heat exchanger 10 of this embodiment has the same outer appearance as that of the first embodiment as viewed from the vehicle front side, and thus can be illustrated as shown in FIG. 1.
As can be seen from the comparison between FIGS. 5 and 2, in this embodiment, the shape of the fin 14, specifically, the dimension of the fin 14 with respect to the tube 12 in the vehicle front-and-rear direction DR3 differs from that of the fin 14 in the first embodiment.
As shown in FIG. 5, in the vehicle front-and-rear direction DR3, that is, in the air flow direction, the width dimension of the fin 14 is set larger than the width dimension of the flat-shaped tube 12, that is, the dimension of the major axis of the tube 12. The position of the end of the fin 14 on the downstream side of the air flow in the air flow direction is the same or substantially the same as that of the end of the tube 12.
On the other hand, the end of the fin 14 on the upstream side of the air flow is positioned to protrude toward the upstream side of the air flow, compared to the position of the end of the tube 12 on the upstream side of the air flow. The protruding amount Dwf of the fin 14 from the tube 12 toward the upstream side of the air flow is larger than a thickness Tcv of the cover member 22 in the air flow direction. In short, the fin 14 protrudes more toward the upstream side of the air flow than the cover member 22 fixed to the upstream side end 121 a of the tube 12 adjacent to the fin 14.
As mentioned above, in this embodiment, the fin 14 protrudes more toward the upstream side of the air flow, compared to the cover member 22 fixed to the upstream side end 121 a of the tube 12 adjacent to the fin 14. Thus, in a step of applying the liquid resin material 221 (see FIG. 4) for the cover member 22 onto the upstream side end 121 a of the tube 12, the fin 14 can easily hold the applied resin material 221 on the upstream side end 121 a of the tube 12, which is another merit of this embodiment.

Other Embodiments

(1) In each of the above-mentioned embodiments, the cover member 22 is made of resin. However, material for the cover member 22 is not limited, but may be, for example, other polymer materials, such as rubber. For example, when the cover member 22 is made of soft material, such as rubber or soft resin, that is, when the cover member 22 has a lower hardness than that of the tube 12, the impact caused when solids collide with the cover member 22 is less likely to be transferred to the tubes 12, compared to when the cover member is not made so, which is another merit of the embodiment.
The cover member 22 may include metal having a lower melting point, such as a solder. If the cover member 22 includes such metal, the cover member 22 is formed by solidifying the melted metal as the material for the cover member 22 at the upstream side end 121 a of the corresponding tube 12.
(2) In each of the above-mentioned embodiments, the upstream side end 121 a of the tube 12 has a shape that expands toward the upstream side of the air flow at the section of the tube 12 perpendicular to the flow direction of the engine coolant, but may have other shapes. For example, the tube 12 may have the sectional shape shown in FIG. 6 or 7.
FIG. 6 is a diagram corresponding to FIG. 2, that is, the sectional view taken along the line II-II of FIG. 1, while showing a first modified example of the section of the tube 12. In the first modified example, as shown in FIG. 6, the upstream side end 121 a of the tube 12 has a planar shape perpendicular to the air flow direction. In other words, the upstream side end 121 a of the tube 12 has the planar shape facing the upstream side of the air flow.
FIG. 7 is a diagram corresponding to FIG. 2, that is, the sectional view taken along the line II-II of FIG. 1, while showing a second modified example of the section of the tube 12. In the second modified example, as shown in FIG. 7, the upstream side end 121 a of the tube 12 has the shape recessed toward the inside of the tube 12 in the air flow direction. In other words, the upstream side end 121 a of the tube 12 has the concave shape recessed toward the inside of the tube 12 on the section of the tube 12 as viewed from the flow direction of the engine coolant.
The tube 12 has the sectional shape shown in FIG. 6 or 7, thereby easily holding the resin material 221 on the upstream side end 121 a in the step of applying the liquid resin material 221 (see FIG. 4) of the cover member 22 onto the upstream side end 121 a of the tube 12, which is another merit of the embodiment.
(3) In each of the above-mentioned embodiments, as shown in FIG. 1, the cover member 22 is provided across the entire length of each of all the tubes 12 of the core portion 16. However, for example, as shown in FIGS. 8 and 9, the cover members 22 may be provided for some parts of tubes 12 in the core portion 16.
FIG. 8 is a diagram showing a first modified example of the positions of formation of the cover members 22 in the heat exchanger 10, which corresponds to FIG. 1. Referring to FIG. 8, the cover members 22 are provided across the entire lengths of the tubes 12. However, unlike FIG. 1, the cover members 22 are not provided for all the tubes 12 in FIG. 8, but only for some of the tubes 12 located under the vehicle.
FIG. 9 is a diagram showing a second modified example of the positions of formation of the cover members 22 in the heat exchanger 10, which corresponds to FIG. 1. Referring to FIG. 9, unlike FIG. 1, the cover members 22 are provided across parts of the entire lengths of some of the plurality of tubes 12 included in the core portion 16. As illustrated in FIGS. 8 and 9, the cover members 22 may be provided in necessary positions of the heat exchanger 10.
(4) In each of the above-mentioned embodiments, the flow of the engine coolant in the heat exchanger 10 is a cross flow where the engine coolant flows in the vehicle width direction DR2. However, the engine coolant flow is not limited thereto, but may be, for example, a down flow where the engine coolant flows from the upward side to the downward side in the vehicle up-and-down direction DR1.
(5) In the above-mentioned second embodiment, the fins 14 protrude more toward the upstream side of the air flow than the cover members 22 fixed to the upstream side ends 121 a of the respective tubes 12. However, the fins 14 may protrude more toward the upstream side of the air flow than only the respective tubes 12, but may not protrude more than the cover members 22. Even with such an arrangement, in the step of applying the liquid resin material 221 (see FIG. 4) onto the upstream side end 121 a of each of the tubes 12, the applied resin material 221 can be easily held on the upstream side ends 121 a of the tubes 12 by the fins 14, which is a merit that this embodiment can obtain to some degree.
The present disclosure is not limited to the embodiments described above, and various modifications and changes can be made to the present disclosure. It is obvious that elements included in each of the above-mentioned embodiments are not necessarily essential unless otherwise specified, and except when clearly considered to be essential in principle. When referring to a specific number about a component of the above-mentioned embodiments, such as the number of components, a numerical value, an amount, or a range, the above-mentioned respective embodiments are not limited to the specific number, unless otherwise specified, except when limited to the specific number in principle, and the like. Further, when referring to the material, shape, positional relationship, or the like of the components, etc., the above-mentioned respective embodiments are not limited to such a material, shape, positional relationship, or the like, unless otherwise specified, and except when clearly limited to the specific material, shape, positional relationship, or the like in principle.

Claims

1. A heat exchanger comprising:

a tube that allows a heat medium flowing therein to exchange heat with air flowing around the tube, the tube having an upstream side end on an upstream side of an air flow; and

a protective member covering the upstream side end and being fixed to the upstream side end to partially cover the tube, the protective member being configured to protect the tube from a solid flying to the tube, wherein

the protective member is made of a polymer material.

2. The heat exchanger according to claim 1, wherein

the protective member has a tip end located on the upstream side of the air flow, and

the tip end of the protective member is formed to be rounded in a section of the protective member perpendicular to a flow direction of the heat medium.

3. The heat exchanger according to claim 1, wherein

a width of the protective member is equal to or less than that of the tube, in a direction perpendicular to an air flow direction and a flow direction of the heat medium.

4. The heat exchanger according to claim 1, wherein

the upstream side end of the tube has a planar shape or a concave shape recessed toward an inside of the tube.

5. The heat exchanger according to claim 1, wherein

fins are provided on both sides of the tube in a direction perpendicular to an air flow direction, to promote heat exchange between the heat medium and the air, and

the fins protrude more toward the upstream side of the air flow than the tube or the protective member.

6. The heat exchanger according to claim 1, wherein

the protective member is made of a material obtained by solidifying a fluid material applied to the upstream side end, the fluid material having fluidity.

7. The heat exchanger according to claim 1, further comprising a plurality of the tubes, wherein

the protective member is fixed at the upstream side ends of a part of the plurality of the tubes.

8. (canceled)

9. (canceled)

10. The heat exchanger according to claim 1, wherein

the protective member is made of one material selected from an acrylic resin, a silicon resin, a resin containing a volatile solvent, a thermosetting resin, and an UV curing resin.

11. (canceled)

12. The heat exchanger according to claim 1, the heat exchanger being disposed outside a vehicle compartment in a vehicle, wherein

the protective member is disposed at a front side of the vehicle with respect to the tube.

13. A heat exchanger for a vehicle, comprising:

a core portion including a plurality of tubes, each of the tubes allowing a heat medium to flow through therein, and fins disposed on both sides of each of the tubes, the core portion being configured to exchange heat between the heat medium and air;

a tank portion connected to an end in a longitudinal direction of the tube; and

a protective member fixed to an upstream end of at least a part of the plurality of tubes on an upstream side of an air flow, wherein

the protective member is disposed at a front side of the vehicle with respect to the tube, and

the protective member is made of a polymer material.

14. The heat exchanger according to claim 13, wherein

the protective member is made of a material obtained by solidifying a fluid material having fluidity.

15. The heat exchanger according to claim 13, wherein

the tube is disposed to have a longitudinal direction set in a width direction of the vehicle.

16. The heat exchanger according to claim 13, wherein

the protective member is fixed to the upstream end of the tube on the upstream side of the air flow, in a lower part of the core portion.

17. The heat exchanger according to claim 13, wherein

the protective member is fixed to a part of the tube in a longitudinal direction of the tube.

18. The heat exchanger according to claim 13, wherein

the fin protrudes more toward the upstream side of the air flow than the tube.

19. The heat exchanger according to claim 18, wherein

the protective member fixed to the end of the tube on the upstream side protrudes more toward the upstream side of the air flow than the fin.

20. The heat exchanger according to claim 1, wherein

the protective member has an upstream end protruding more toward the upstream side of the air flow than the fins.

21. The heat exchanger according to claim 1, wherein

the protective member has an upstream end having a cross-sectional area expanding toward upstream in the air flow.

22. The heat exchanger according to claim 1, wherein the protective member has a hardness smaller than that of the tube.