JP2017116208A - Mounting structure of heat transfer tube, heat exchanger, and mounting method of heat transfer tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mounting structure of a heat transfer tube capable of improving mounting strength of the heat transfer tube in comparison with the prior art, with a simple constitution.SOLUTION: A through hole 22 of a mounted object member 21 to which an end portion of a heat transfer tube 1 of a heat exchanger is inserted, is a taper hole portion 22a of which an inner diameter is expanded toward a tip side of the heat transfer tube 1 as a whole, or has the taper hole portion 22a and a non-taper hole portion 22b connected to a small diameter side of the taper hole portion 22a, and is constituted so that a width in an axial direction of the taper hole portion 22a is larger than that of the non-taper hole portion 22b. The end portion of the heat transfer tube 1 is provided with a taper pipe expansion portion 12 so that an outer peripheral face has an inclined face along an inner peripheral face of the taper hole portion 22a, and a brazing portion 4 is formed between the outer peripheral face of the taper pipe expansion portion 12 and the inner peripheral face of the taper hole portion 22a.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a technique for fixing and attaching a heat transfer tube as a component of a heat exchanger to a predetermined member.

There exists a structure of patent document 1 as an example of the attachment structure of the heat exchanger tube in a heat exchanger.
In the structure described in the same document, an end portion of the heat transfer tube is inserted into a through hole provided in a member to which the heat transfer tube is attached, and the end portion is subjected to a tube expansion process, thereby It is in pressure contact with the inner peripheral surface of the through hole. A part of the through hole is a tapered hole, whereby a recess for allowing the brazing material to enter is formed between the inner peripheral surface of the through hole and the outer peripheral surface of the heat transfer tube. . The brazing material brazes the heat transfer tube and the attachment target member.
According to such a configuration, since the expansion and brazing of the heat transfer tube are used together, it is possible to fix the heat transfer tube to the attachment target member with a relatively high strength.

  However, the prior art still has room for improvement as described below.

That is, in the heat exchanger, it is desirable to make the mounting strength of the heat transfer tube as high as possible and to have high reliability. For this purpose, it is desirable to increase as much as possible the area in which the outer peripheral surface of the heat transfer tube and the inner peripheral surface of the through hole are brazed so as to face each other or face each other. However, in the prior art, since most of the through holes are non-tapered holes (straight holes having the same diameter), for example, the thickness of the attachment target member is not so large, and the depth of the through holes When it is not possible to take a large value, the area of the inner peripheral surface of the through hole becomes small. As a result, the inner peripheral surface of the through-hole and the outer peripheral surface of the heat transfer tube cannot be opposed to each other or opposed to each other over a wide area, and the mounting strength of the heat transfer tube is reduced.
In addition, a part of the through hole is a tapered hole part, and this part is filled with brazing material, but the inner peripheral surface of the tapered hole part and the outer peripheral surface of the heat transfer tube are separated with a relatively large size. doing. For this reason, the brazing strength of the heat transfer tube in the tapered hole is slightly inferior.

JP-A-9-133491

  The present invention has been conceived under the circumstances as described above, and has a heat transfer tube mounting structure and heat exchange that can increase the heat transfer tube mounting strength over the prior art with a simple configuration. It is an object of the present invention to provide a heater and a method for attaching a heat transfer tube.

  In order to solve the above problems, the present invention takes the following technical means.

The heat transfer tube mounting structure provided by the first aspect of the present invention includes a heat transfer tube of a heat exchanger, and a heat transfer tube mounting target member having a through hole into which an end of the heat transfer tube is inserted. The heat transfer tube mounting structure is provided, wherein the entire through hole is a tapered hole portion whose inner diameter increases toward the tip end side of the heat transfer tube, or is connected to the tapered hole portion and the smaller diameter side thereof. A non-tapered hole portion, and the tapered hole portion is configured to have a larger axial length than the non-tapered hole portion. A taper tube expansion portion is formed so as to be an inclined surface along the inner peripheral surface of the taper hole portion, and between the outer peripheral surface of the taper tube expansion portion and the inner peripheral surface of the taper hole portion, A brazing part is formed.

According to such a configuration, the following effects can be obtained.
That is, the whole or most of the through hole of the attachment target member into which the end of the heat transfer tube is inserted is a tapered hole, and the outer peripheral surface of the end of the heat transfer tube is the inside of the tapered hole. Since it is expanded so that it becomes an inclined surface along the peripheral surface, it is possible to make the area where the outer peripheral surface of these heat transfer tubes and the inner peripheral surface of the through hole face each other or face each other is larger than that of the prior art. It is. In addition, since a brazed portion is formed between the outer peripheral surface of the taper expanded portion and the inner peripheral surface of the tapered hole portion, the brazed area between the heat transfer tube and the mounting target member may be increased. Is possible. Even when the taper expansion portion of the heat transfer tube is relatively strongly pressed against the inner peripheral surface of the taper hole portion, there is a minute gap between them, so that the heat-melted brazing material can be used as a capillary tube. Depending on the phenomenon, it is possible to enter the minute gap between them. For this reason, according to the present invention, it is possible to increase the mounting strength of the heat transfer tube and improve its reliability as compared with the prior art. According to the present invention, even if the thickness dimension of the attachment target member is not so large, the attachment strength of the heat transfer tube can be sufficiently ensured.
Furthermore, according to the present invention, the taper expansion portion of the heat transfer tube has a structure engaged with the inner peripheral surface of the taper hole portion of the through hole in the axial direction of the heat transfer tube. For this reason, when a pulling force toward the proximal end is generated in the heat transfer tube, the pulling force is received by the inner peripheral surface of the tapered hole portion that engages with the taper expanded portion, and the heat transfer tube moves in the pulling direction. Be blocked. Therefore, it is possible to further increase the mounting strength of the heat transfer tube.

  In the present invention, preferably, the through hole has the tapered hole portion and the non-tapered hole portion, and the tapered hole portion has a larger width in the axial length direction than the non-tapered hole portion. In addition, a non-tapered tube expanding portion is further formed at the end of the heat transfer tube so that the outer peripheral surface is expanded along the inner peripheral surface of the non-tapered hole portion.

According to such a configuration, the following effects can be obtained.
That is, since the inner peripheral surface of the non-tapered hole portion of the through hole is narrow and non-inclined, when the outer peripheral surface of the non-tapered expanded portion is pressed against the inner peripheral surface by pipe expansion, the pressure contact It is possible to increase the force partially and increase the caulking strength. For this reason, the heat transfer tube can be positioned and fixed more accurately with respect to the attachment target member than when the entire through-hole is a tapered hole.

  In this invention, Preferably, the brazing part is formed between the outer peripheral surface of the said non-taper pipe expansion part, and the inner peripheral surface of the said non-taper hole part.

  According to such a configuration, the brazing area between the heat transfer tube and the attachment target member can be further increased, and the attachment strength of the heat transfer tube can be further increased.

  The heat exchanger provided by the second aspect of the present invention includes a plurality of heat transfer tubes and a member to be attached to which ends of the plurality of heat transfer tubes are attached, and the inside of each of the plurality of heat transfer tubes. And a header for hot water inflow or outflow formed in a chamber communicating with the heat exchanger, wherein the heat exchanger has a structure for mounting the plurality of heat transfer tubes to the mounting target member. The heat transfer tube mounting structure provided by the first aspect of the present invention is used.

According to such a structure, the effect similar to having described the attachment structure of the heat exchanger tube provided by the 1st side surface of this invention is acquired, and the attachment strength of a heat exchanger tube and a header can be raised.

  In the present invention, preferably, the tapered hole portion and the tapered pipe expanding portion have a larger diameter as they approach the chamber, and an end portion on the large diameter side of the tapered pipe expanding portion is connected to a distal end portion of the heat transfer tube. In addition, the tip portion is configured not to protrude from the inside of the tapered hole portion into the chamber.

  According to such a configuration, when hot water flows in and out between the header chamber and the heat transfer tube, the tip of the heat transfer tube can be prevented from becoming a large resistance. That is, unlike the above-described configuration, when the tip of the heat transfer tube protrudes into the chamber, this protruding portion serves as resistance to hot water flow, but according to the configuration, such a problem is eliminated. . In addition, since the inner diameter of the heat transfer tube gradually increases as it approaches the chamber, this also provides a smooth flow of hot water between the heat transfer tube and the chamber. For this reason, it is possible to reduce the flow path resistance of hot water in the heat exchanger.

  In the present invention, preferably, it includes a case in which the plurality of heat transfer tubes are housed and a fluid for heating the plurality of heat transfer tubes is supplied to the inside. The attachment target member, and the header is configured by joining an internal hollow and front opening header forming member having an opening as a water inlet or a hot water outlet to the side wall of the case.

  According to such a configuration, it is possible to realize a header with high heat transfer tube mounting strength with a simple configuration, and to reduce the manufacturing cost of the heat exchanger.

  The heat transfer tube mounting method provided by the third aspect of the present invention is for mounting the heat transfer tube of the heat exchanger to the heat transfer tube mounting target member having a through hole into which an end of the heat transfer tube is inserted. The heat transfer tube mounting method according to claim 1, wherein the through-hole has a tapered hole portion as a whole, or a tapered hole portion and a non-tapered hole portion connected to the small diameter side thereof, and the non-tapered hole portion. The tapered hole portion is configured to have a larger axial length, and the outer peripheral surface is the inner peripheral surface of the tapered hole portion by inserting the end portion of the heat transfer tube into the through hole and expanding the tube. And a tube expansion step for forming a tapered tube expansion portion that is expanded so as to be an inclined surface along the tube, and after this tube expansion step, heating is performed between the outer peripheral surface of the taper expansion portion and the inner peripheral surface of the taper hole portion. A brazing process in which the molten brazing material enters by It is characterized by having a.

  According to such a structure, the attachment structure of the heat exchanger tube provided by the 1st side surface of this invention can be obtained appropriately.

  Other features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention with reference to the accompanying drawings.

(A) is a plane sectional view showing an example of the heat exchanger concerning the present invention, and (b) is a front sectional view of (a). (A) is the expanded sectional view of the IIa part of FIG.1 (b), (b) is the IIb-IIb plane expanded sectional view of (a). It is sectional drawing which expanded the principal part of FIG.1 (b) further. (A)-(d) is principal part sectional drawing which shows an example of the manufacturing method for obtaining the structure shown in FIG. It is principal part sectional drawing which shows the other example of this invention. (A), (b) is principal part sectional drawing which shows the other example of this invention.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

A heat exchanger HE shown in FIG. 1 is a hot water heating heat exchanger used as a component of a hot water supply device, and includes a plurality of heat transfer tubes 1 through which hot water flows, and the plurality of heat transfer tubes 1 inside. A case 2 to be accommodated, and a pair of headers 3 (3A, 3B) for water entry and hot water provided on the side surface of the case 2 are provided.
In this heat exchanger HE, combustion gas generated by a burner (not shown) such as a gas burner flows into the case 2 from the air supply port 28 of the case 2 and proceeds toward the exhaust port 29, and this process The combustion gas acts on each heat transfer tube 1 in FIG. On the other hand, the hot water supplied to the incoming header 3A flows through the plurality of heat transfer tubes 1 and is heated by the combustion gas. The heated hot water reaches the header 3B for hot water, and hot water is discharged from the header 3B toward a predetermined location.

  The case 2 includes a rectangular cylindrical case main body 20 having both ends in the left-right width direction opened, and a pair of plate-shaped side walls 21 and 21A that close the openings at both ends in the width direction of the case main body 20. ing. Each heat transfer tube 1 includes a helical tube portion 10 formed in a substantially rectangular shape or an oval shape in plan view, and a straight tubular extending tube portion connected to the lower portion and the upper portion thereof and extending substantially horizontally. 11a, 11b. The plurality of spiral tubular body portions 10 have different sizes and are arranged substantially concentrically.

The end portions of the heat transfer tubes 1 (end portions of the extended tube portions 11a and 11b) are attached to the side wall portion 21 of the case 2, and the structure of this portion is the heat transfer tube mounting structure according to the present invention. It corresponds to an example. The side wall 21 corresponds to an example of a heat transfer tube attachment target member in the present invention.
The header 3 is formed by welding a header forming member 30 to the side wall 21. As shown well in FIG. 2A, the header forming member 30 has an inner cavity shape having a front side opening 31 and having an opening 32 as a water inlet or outlet on the rear side. It is. The header forming member 30 is joined to the side wall portion 21 so that the front-side opening 31 is closed by the side wall portion 21, so that the header forming member 30 has an inside of each heat transfer tube 1 inside. A chamber 33 communicated with is formed.

  As clearly shown in FIG. 3, the side wall portion 21 is provided with a through hole 22 into which the end of the heat transfer tube 1 is inserted, and the inner diameter of the through hole 22 becomes closer to the chamber 33. It has a taper hole 22a that expands, and a non-taper hole 22b that is connected to the smaller diameter side of the taper hole 22a and has an inner diameter that is substantially constant. In the axial length direction of the through hole 22, the width La of the tapered hole portion 22 a is larger than the width Lb of the non-tapered hole portion 22 b (see also FIG. 4A).

  A tapered pipe expanding portion 12 and a non-tapered pipe expanding portion 13 are connected to the end of the heat transfer tube 1. The taper expanded portion 12 is a portion expanded so that the outer peripheral surface becomes an inclined surface along the inner peripheral surface of the tapered hole portion 22a. A region of a minute gap between the outer peripheral surface of the taper expanded portion 12 and the inner peripheral surface of the tapered hole portion 22a is formed by a brazing portion 4 in which a brazing material enters and joins the outer peripheral surface and the inner peripheral surface. Has been. The distal end portion 12a (the distal end portion of the heat transfer tube 1) on the large diameter side of the taper expanded tube portion 12 is located in the through hole 22 so as not to protrude toward the chamber 33 side. Preferably, the tip end portion 12a is substantially flush with the outer side surface 21a (side surface facing the chamber 33) of the side wall portion 21.

The non-taper tube expansion portion 13 is a portion that is expanded so that the outer peripheral surface is along the inner peripheral surface of the non-taper hole portion 22b. Preferably, a region of a minute gap between the outer peripheral surface of the non-taper expanded tube portion 13 and the inner peripheral surface of the non-taper hole portion 22b is a brazed portion 4A that joins the outer peripheral surface and the inner peripheral surface. ing.
Such a heat transfer tube mounting structure is similarly employed not only in the incoming water header 3A shown in FIG. 2, but also in the hot water header 3B shown in FIG.

  The above heat transfer tube mounting structure can be obtained through a series of steps as shown in FIG. That is, as shown in FIG. 5A, a through hole 22 in which the non-tapered hole 22b is connected to the tapered hole 22a described above is formed in the side wall 21 in advance. The end of the heat transfer tube 1 is inserted into Next, as shown in FIGS. 2B and 2C, a punch 9 having a pressing surface corresponding to the tapered hole portion 22a and the non-tapered hole portion 22b is inserted into the end portion of the heat transfer tube 1 to expand the pipe, The outer peripheral surface of the end portion of the heat tube 1 is set along each part of the inner peripheral surface of the through hole 22. After the tube expansion, the heat transfer tube 1 is brazed to the side wall portion 21 as shown in FIG. For this brazing, for example, a paste-like brazing material is used for the portion A1 where the outer surface 21a of the side wall 21 and the tip 12a of the heat transfer tube 1 are adjacent, and the inner surface 21b of the side wall 21 and the outer peripheral surface of the heat transfer tube 1. In a state where it is applied to the portion A2 where the crossing and the brazing material, the brazing material is heated and melted using a heating furnace. The heated and melted brazing material enters into the minute gap formed between the inner peripheral surface of the through hole 22 and the outer peripheral surface of the heat transfer tube 1 by a capillary phenomenon. As a result, the above-described brazing portions 4 and 4A can be formed.

  Next, the operation of the heat exchanger HE described above will be described.

  First, since most of the through holes 22 in the side wall portion 21 are tapered holes 22a, the substantial width dimension Lc (see FIG. 3) can be increased. On the other hand, since the inclined outer peripheral surface of the taper expanded portion 12 of the heat transfer tube 1 faces the inner peripheral surface of the tapered hole portion 22a in a parallel state, the inner peripheral surface and the outer peripheral surface It is possible to increase the facing area. In addition, since the region of the minute gap between the inner peripheral surface and the outer peripheral surface is the brazing portion 4, the brazing area between the heat transfer tube 1 and the side wall portion 21 can be increased. is there. Therefore, even when the thickness t of the side wall portion 21 is not so large, the attachment strength of the heat transfer tube 1 to the side wall portion 21 can be increased.

In addition, the through hole 22 has a small but non-tapered hole 22b, and the inner peripheral surface of the non-tapered hole 22b is along the outer peripheral surface of the non-tapered expanded portion 13 of the heat transfer tube 1. Since it is a structure, in this part, it is possible to make the crimping state of the heat exchanger tube 1 with respect to the side wall part 21 strong. In addition, as described above, brazing by the brazing unit 4A is also performed in such a caulking portion. Therefore, the attachment strength of the heat transfer tube 1 to the side wall portion 21 can be further increased.
The taper expanding portion 12 of the heat transfer tube 1 is engaged with the inner peripheral surface of the taper hole portion 22a in the axial length direction and prevents the heat transfer tube 1 from moving to the base end side (left side in FIG. 3). The function to perform is also demonstrated. Thereby, the attachment strength of the heat transfer tube 1 is further improved.

As shown in FIG. 2, in the incoming header 3A, hot water flows into the heat transfer tubes 1 from the chamber 33, but the tip 12a of each heat transfer tube 1 does not protrude toward the chamber 33. It is possible to reduce the resistance to. Unlike the present embodiment, when the tip 12a of each heat transfer tube 1 protrudes toward the chamber 33, this protruding portion hinders hot water flow. On the other hand, according to this embodiment, there is no such inconvenience. Further, in the present embodiment, each heat transfer tube 1 has a so-called widening shape due to the presence of the tapered tube expansion portion 12, so that the hot water flows from the chamber 33 into the heat transfer tube 1 more smoothly. Even in the header 3B for hot water, the same action as described for the header 3A for incoming water can be obtained. From such a thing, the advantage which can make the flow path resistance in the hot-water flow path of the heat exchanger HE small can be acquired.

  5 and 6 show another example of the present invention. In these drawings, elements that are the same as or similar to those in the above embodiment are denoted by the same reference numerals as those in the above embodiment, and redundant description is omitted.

  In the embodiment shown in FIG. 5, an additional tube expansion portion 14 is formed at a position closer to the base end side than the non-taper tube expansion portion 13 in the heat transfer tube 1. The additional pipe expanding portion 14 is locked to the inner side surface 21 b of the side wall portion 21. According to such a configuration, the side wall portion 21 is sandwiched between the additional tube expansion portion 14 and the taper tube expansion portion 12, and the positioning and fixing of the heat transfer tube 1 in the axial length direction with respect to the side wall portion 21 is further strengthened. Can be aimed at.

  In the embodiment shown in FIG. 6 (a), a convex portion 21c is formed on the side wall portion 21, and the header 3 is formed by the header forming member 30 being fitted on the convex portion 21c. ing. According to such a configuration, it is preferable for positioning the header forming member 30 with respect to the side wall 21 and welding the side wall 21 and the header forming member 30 easily and accurately.

In the embodiment shown in FIG. 6B, the end of the heat transfer tube 1 is attached to the auxiliary member 26 that is separate from the side wall 21. The side wall part 21 has a convex part 25 pushed out of the case 2, and the auxiliary member 26 is joined to the side wall part 21 so as to close the opening inside the convex part 25. . Thus, the header 3C having the chamber 33 is configured.
As understood from the present embodiment, in the present invention, when the header of the heat exchanger is formed, it is possible to adopt a structure in which the heat transfer tube is attached to a member different from the side wall portion of the case.

  The present invention is not limited to the contents of the above-described embodiment. The mounting structure of the heat transfer tube according to the present invention and the specific configuration of each part of the heat exchanger can be variously modified within the intended scope of the present invention. The specific configuration of each step in the heat transfer tube mounting method of the present invention can be variously changed.

The through-hole into which the end portion of the heat transfer tube is inserted may be configured such that the entire through-hole is a tapered tube-expanded portion, instead of the configuration in which both the tapered tube-expanded portion and the non-taper tube-expanded portion are formed.
The member to which the heat transfer tube is attached in the present invention is not limited to the side wall portion of the case of the heat exchanger or the auxiliary member 26 shown in FIG. 6B, but other than this, for example, separate from the side wall portion of the case. Any one of the constituent members of the header for incoming water or hot water constituted by the plurality of members may be an attachment target member of the heat transfer tube. The heat transfer tube is not limited to a type having a spiral tube body portion, and may be another type of heat transfer tube having a shape such as a straight tube or a meandering shape.

HE heat exchanger 1 heat transfer tube 12 taper expanded tube portion 12a tip portion 13 non-taper expanded tube portion 2 case 21 side wall (member to which heat transfer tube is attached)
22 Through-hole 22a Tapered hole 22b Non-tapered hole 3 Header 30 Header forming member 31 Front side opening (opening of header forming member)
33 Chamber 4, 4A brazing part

Claims (7)

A heat exchanger tube,
The heat transfer tube attachment target member having a through-hole into which the end of the heat transfer tube is inserted;
A heat transfer tube mounting structure comprising:
The through-hole has a tapered hole part whose entire inner diameter increases toward the distal end side of the heat transfer tube, or has a non-tapered hole part connected to the small-diameter side thereof. The tapered hole portion is configured to have a greater width in the axial length direction than the hole portion,
At the end of the heat transfer tube, a tapered tube expansion portion is formed that is expanded so that the outer peripheral surface becomes an inclined surface along the inner peripheral surface of the tapered hole portion,
A heat transfer tube mounting structure, wherein a brazed portion is formed between the outer peripheral surface of the taper tube expansion portion and the inner peripheral surface of the taper hole portion. The heat transfer tube mounting structure according to claim 1,
The through hole has the tapered hole portion and the non-tapered hole portion, and the tapered hole portion is configured to have a larger width in the axial length direction than the non-tapered hole portion,
A heat transfer tube mounting structure in which an end portion of the heat transfer tube is further formed with a non-taper tube expansion portion whose outer peripheral surface is expanded so as to be along the inner peripheral surface of the non-taper hole portion. The heat transfer tube mounting structure according to claim 2,
A heat transfer tube mounting structure in which a brazed portion is formed between the outer peripheral surface of the non-tapered tube expanding portion and the inner peripheral surface of the non-tapered hole portion. A plurality of heat transfer tubes;
A header for inflow or outflow of hot water having a member to be attached to which ends of the plurality of heat transfer tubes are attached, and a chamber communicating with the inside of each of the plurality of heat transfer tubes;
A heat exchanger comprising:
A heat exchanger, wherein the heat transfer tube mounting structure according to any one of claims 1 to 3 is used as a mounting structure of the plurality of heat transfer tubes to the mounting target member. The heat exchanger according to claim 4,
The tapered hole portion and the tapered pipe expanding portion become larger in diameter as they approach the chamber, and an end portion on the large diameter side of the tapered expanding portion is a tip portion of the heat transfer tube, and the tip portion is The heat exchanger is configured not to protrude into the chamber from the tapered hole portion. The heat exchanger according to claim 4 or 5,
A case in which the plurality of heat transfer tubes are housed inside and a fluid for heating the plurality of heat transfer tubes is supplied to the inside;
The side wall portion of the case is the attachment target member,
The header is a heat exchanger configured by joining an inner hollow and front opening header forming member having an opening as a water inlet or a hot water outlet to a side wall of the case. A heat transfer tube mounting method for mounting a heat transfer tube of a heat exchanger to a heat transfer tube mounting target member having a through hole into which an end of the heat transfer tube is inserted,
The through hole has a tapered hole part as a whole, or has a tapered hole part and a non-tapered hole part connected to the smaller diameter side, and the tapered hole part is more axial than the non-tapered hole part. A configuration with a large width in the long direction,
Expanding the tube by inserting the end of the heat transfer tube into the through-hole and expanding the tube so that the outer peripheral surface becomes an inclined surface along the inner peripheral surface of the tapered hole; and ,
After this pipe expanding step, a brazing step for allowing a brazing material melted by heating to enter between the outer peripheral surface of the tapered pipe expanding portion and the inner peripheral surface of the tapered hole portion;
A heat transfer tube mounting method, characterized by comprising:

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