JP2016166685A - Exhaust heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a processing load when molding a core plate in an exhaust heat exchanger that can prevent a tube end from protruding from the core plate.SOLUTION: An exhaust heat exchanger for exchanging heat between exhaust gas discharged from an internal combustion engine 10 and a cooling medium includes: a plurality of tubes 110 in which the exhaust gas flows; a casing 130 for storing the tubes 110 and making the cooling medium flow outside the tubes 110; and core plates 140 disposed at ends of the tubes 110 in the casing 130 to prevent outflow of the cooling water from the casing 130. The core plate 140 includes through holes 140a into which the tubes 110 are inserted. Movement restriction portions 140b for restricting axial movement of the tubes 110 are provided at part of inner peripheral portions of the through holes 140a.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an exhaust heat exchanger that cools exhaust gas by exchanging heat between exhaust gas generated by combustion and a cooling medium.

  Conventionally, an exhaust heat exchanger that cools exhaust gas by exchanging heat between the exhaust gas of the internal combustion engine and a cooling medium is known. In such an exhaust heat exchanger, when both ends of the tube through which the exhaust flows are fixed to the core plate (header plate), the downstream end of the tube in the exhaust flow direction protrudes from the core plate. If this is the case, the condensed water generated by cooling the exhaust gas may stay around the core plate and the tube and cause corrosion. For this reason, the structure which prevents that a tube edge part protrudes from a core plate by providing the movement control part which controls the movement of a tube axial direction in a core plate is proposed (refer patent document 1).

JP2013-24109A

  However, in the exhaust heat exchanger described in Patent Document 1, a movement restricting portion is provided over the entire circumference of the through hole of the core plate, and the processing load when the core plate is press-molded becomes excessive. For this reason, it is necessary to enlarge a processing equipment, and it leads to a cost increase. In addition, it is desirable to use stainless steel for the core plate in contact with the exhaust of the internal combustion engine from the viewpoint of heat resistance and corrosion resistance. However, when stainless steel is used for the core plate, the processing load during molding becomes excessive. The problem becomes particularly prominent.

  Moreover, when joining a tube and a core plate by brazing, it is necessary to apply | coat a brazing material also to a movement control part. For this reason, when providing a movement control part over the perimeter of the through-hole of a core plate, the usage-amount of brazing material increases and it leads to a cost increase.

  In view of the above, an object of the present invention is to reduce a processing load during molding of a core plate in an exhaust heat exchanger capable of preventing the tube end portion from protruding from the core plate.

In order to achieve the above object, according to the first aspect of the present invention, there is provided an exhaust heat exchanger for exchanging heat between the exhaust discharged from the internal combustion engine (10) and the cooling medium,
A plurality of tubes (110) through which the exhaust gas circulates, a casing (130) in which the tubes (110) are housed and a cooling medium circulates outside the tubes (110), and the tubes (110) inside the casing (130) A core plate (140) disposed at the end to prevent cooling water from flowing out of the casing (130);
The core plate (140) is provided with a through hole (140a) into which the tube (110) is inserted, and a movement restricting portion (140b) for restricting the axial movement of the tube (110) is provided in the through hole (140a). It is characterized in that it is provided in a part of the inner peripheral part.

  According to this, since the movement control part (140b) is provided in a part of inner peripheral part of the through-hole (140a), the processing load at the time of press-molding the core plate (140) can be reduced. For this reason, it is not necessary to enlarge the processing equipment of the core plate (140), and it is possible to extend the life of the mold. This is particularly effective in a configuration in which stainless steel having a large processing load is used for the core plate (140).

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

It is a schematic diagram which shows EGR using the EGR cooler of 1st Embodiment. It is a top view which shows the inside of the EGR cooler of 1st Embodiment. It is a front view which shows the inside of the EGR cooler of 1st Embodiment. It is a perspective view which shows the tube of 1st Embodiment. It is a front view which shows the core plate of 1st Embodiment. It is VI-VI sectional drawing of FIG. It is VII-VII sectional drawing of FIG. It is a front view of the core plate of 2nd Embodiment. It is a perspective view which shows the overlap part of the tube of 2nd Embodiment, and the junction part of a core plate. It is XX sectional drawing of FIG. It is a front view of the core plate of 3rd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. In the present embodiment, an example in which the exhaust heat exchanger of the present invention is applied to an EGR cooler will be described. An EGR cooler is an exhaust heat exchanger that cools exhaust gas generated by combustion in an engine (internal combustion engine) to the engine using engine coolant (cooling medium).

  As shown in FIG. 1, an EGR (exhaust gas recirculation device) is a device for reducing nitrogen oxides in exhaust gas provided in an engine 10 of a vehicle, and includes an exhaust gas recirculation pipe 11, an EGR valve 12, and an EGR cooler. 100. The exhaust gas recirculation pipe 11 is a pipe that recirculates a part of the exhaust gas discharged from the engine 10 to the intake side of the engine 10. The inlet of the exhaust gas recirculation pipe 11 is connected to the exhaust gas upstream side of the exhaust gas purification catalyst 13.

  The EGR valve 12 is disposed in the middle of the exhaust gas flow in the exhaust gas recirculation pipe 11 and adjusts the amount of exhaust gas (hereinafter also referred to as EGR gas) flowing through the exhaust gas recirculation pipe 11 according to the operating state of the engine 10. Is. The EGR cooler 100 is a heat exchanger that performs heat exchange between the EGR gas and the coolant of the engine 10 to cool the EGR gas, and is disposed between the exhaust side of the engine 10 and the EGR valve 12. Yes.

  Next, the structure of the EGR cooler 100 will be described with reference to FIGS. 2 and 3, the casing 130 and the like are shown in cross section in order to illustrate the tube 110.

  2 and 3, the EGR cooler 100 includes a tube 110, fins 120, a casing 130, a core plate 140, an inflow side tank unit 150, an outflow side tank unit 160, an inflow port 170, an outflow port 180, and the like. ing. Each member is made of, for example, a stainless material having excellent heat resistance and corrosion resistance, and the contact portions of the members are joined to each other by brazing.

  As shown in FIG. 4, the tube 110 is a tube member that forms an exhaust passage 111 through which EGR gas flows, and a cross section that intersects the flow direction of the EGR gas is formed in a rectangular flat shape. The tube 110 is formed, for example, by joining the U-shaped opening side end portions of two tube plates 110a and 110b press-molded into a U-shape having a shallow cross section. A plurality of tubes 110 are stacked such that the long side surfaces (hereinafter referred to as facing surfaces) of the flat cross section face each other.

  On the opposite surface of the tube 110, a convex portion 112 that protrudes outward is formed. The convex portion 112 is formed simultaneously with the press forming of the tube plates 110a and 110b.

  The fin 120 is a heat transfer member that promotes heat exchange between the EGR gas and the cooling water, and is disposed in the tube 110, that is, in the exhaust passage 111. The detailed configuration of the fin 120 will be described later.

  As shown in FIG. 2 and FIG. 3, the casing 130 accommodates therein a laminated body of the tubes 110 that are laminated and joined by the convex portions 112, and the cooling water flows around the laminated body of the tubes 110. This is a rectangular pipe-shaped container body that forms the cooling water passage 131. The cooling water passage 131 is a passage formed between the tube 110 and the tube 110 and between the tube 110 and the casing 130.

  The core plate 140 is a pair of plate members provided with a plurality of through holes. The plurality of tubes 110 are held by the pair of core plates 140 by through-joining both ends in the longitudinal direction of the plurality of stacked tubes 110 in the through holes of the pair of core plates 140. The outer peripheral portions of the pair of core plates 140 are joined to the inner peripheral surface of the casing 130. A pair of core plates 140 partitions a cooling water passage 131 in the casing 130 and internal spaces of tank units 150 and 160 described later.

  The inflow side tank unit 150 is a funnel-shaped member that distributes and supplies EGR gas to each tube 110, and the end of the funnel-shaped large opening area is one end side in the longitudinal direction of the casing 130 (FIG. 2, FIG. 2). 3 (left side of 3) (specifically, the opening side inner peripheral surface of the core plate 140). A joint portion 151 for connecting to an intermediate portion of the exhaust gas recirculation pipe 11 is joined to an end portion of the inflow side tank portion 150 on the side having a small funnel-shaped opening area.

  The outflow side tank section 160 is a funnel-shaped member that collects EGR gas flowing out from each tube 110, and the end of the funnel-shaped large opening area is the other end side in the longitudinal direction of the casing 130 (FIG. 2). 3 is bonded to the opening (specifically, the opening side inner peripheral surface of the core plate 140). A joint portion 161 for connecting to an intermediate portion of the exhaust gas recirculation pipe 11 is joined to the end portion of the outflow side tank portion 160 on the side having a small funnel-like opening area.

  The inflow port 170 is a pipe member that introduces cooling water into the cooling water passage 131, and the EGR gas of the casing 130 is communicated with the inside of the inflow port 170 and the inside of the casing 130 (cooling water passage 131). It is joined to the inflow side.

  Outflow port 180 is a pipe member that causes the cooling water flowing through cooling water passage 131 to flow out to the outside. Casing 130 is arranged so that the inside of outflow port 180 communicates with the inside of casing 130 (cooling water passage 131). It is joined to the outflow side of the EGR gas.

  Next, the detailed structure of the core plate 140 of this embodiment is demonstrated based on FIGS. As shown in FIG. 5, the core plate 140 is configured as a plate-like member, and a plurality of through holes 140a are formed on the plate surface. The through hole 140a of the core plate 140 has a shape corresponding to the flat cross section of the tube 110, and the longitudinal end portion of the tube 110 is inserted therein.

  A movement restricting portion 140b for restricting the movement of the tube 110 is provided on the inner peripheral portion of the through hole 140a. The movement restricting portion 140b is provided so as to protrude from the inner peripheral wall surface of the through hole 140a toward the center of the through hole 140a. The movement restricting portion 140b is provided in a part of the inner peripheral portion of the through hole 140a, and the inner peripheral portion of the through hole 140a is provided with a portion where the movement restricting portion 140b is provided and the movement restricting portion 140b. There are no sites.

  In the present embodiment, the pair of movement restricting portions 140b are provided so as to face each other in the vicinity of the center of the through hole 140a in the longitudinal direction. That is, in this embodiment, two movement restricting portions 140a are provided on the long side of the through hole 140a.

  6 and 7, the tube 110 is indicated by a broken line, and the tube 110 is inserted into the through hole 140a of the core plate 140 from the upper side to the lower side of the drawing.

  As shown in FIG. 6, the movement restricting portion 140b is provided on the inner peripheral wall surface of the through hole 140a of the core plate 140 so as to protrude toward the inside of the through hole 140a. The protruding length of the movement restricting portion 140b corresponds to the plate thickness of the tube 140a. Further, the movement restricting portion 140b is formed on the inner wall surface of the through hole 140a on the insertion direction side of the tube 110 (lower side in FIG. 6).

  In the portion of the through hole 140a where the movement restricting portion 140b is provided, the inner diameter of the through hole 140a is smaller than the thickness of the tube 110, and a step is formed on the inner peripheral wall surface of the through hole 140a. For this reason, when the tube 110 is inserted into the through hole 140a of the core plate 140, the movement of the tube 110 is regulated by the longitudinal end portion of the tube 110 coming into contact with the movement restricting portion 140b, and the longitudinal end portion of the tube 110 is the core. Protruding from the plate surface of the plate 140 can be prevented.

  As shown in FIG. 7, the movement restricting portion 140b is not provided in a portion other than the vicinity of the center in the longitudinal direction in the through hole 140a. For this reason, the level | step difference is not formed in the inner peripheral wall surface of the through-hole 140a.

  Prior to brazing, a brazing material is applied to the portion of the inner peripheral wall surface of the through hole 140a of the core plate 140 where the tube 110 abuts. That is, in the part where the movement restricting part 140b is provided in the through hole 140a shown in FIG. 6, the part where the side surface of the tube 110 contacts in the through hole 140a and the part where the tip of the tube 110 contacts in the movement restricting part 140b. The material is applied. In the part where the movement restricting portion 140b is not provided in the through hole 140a shown in FIG. 7, the brazing material is applied only to the part where the side surface of the tube 110 abuts in the through hole 140a.

  According to the present embodiment described above, by providing the movement restricting portion 140b in the through hole 140a of the core plate 140, it is possible to prevent the longitudinal tip of the tube 110 from protruding from the core plate 140. Moreover, in this embodiment, since the movement control part 140b is provided only in a part of inner peripheral part of the through-hole 140a, the processing load at the time of press-molding the core plate 140 can be reduced. For this reason, it is not necessary to enlarge the processing equipment of the core plate 140, and it is possible to extend the life of the mold. This is particularly effective in a configuration in which the core plate 140 is made of stainless steel having a processing load larger than that of aluminum as in the present embodiment.

  Further, according to the present embodiment, since the movement restricting portion 140b is provided in a part of the inner peripheral portion of the through hole 140a, the brazing material applied to the portion of the movement restricting portion 140b where the tip of the tube 110 abuts is provided. The amount used can be reduced. For this reason, it is possible to reduce the cost of the brazing filler metal and further to shorten the cycle time of the brazing filler metal coating process.

  Further, according to the present embodiment, by providing the movement restricting portion 140b on the long side of the through hole 140a of the core plate 140, the processing accuracy of the movement restricting portion 140b can be improved.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. The second embodiment is different in the configuration of the core plate 140 from the first embodiment.

  As shown in FIG. 8, in the core plate 140 of the second embodiment, a pair of movement restricting portions 140b are provided at both ends of the through hole 140a in the longitudinal direction. That is, in the second embodiment, two movement restricting portions 140a are provided on the short side of the through hole 140a. In the configuration shown in FIG. 8 as well, the cross section of the portion of the through hole 140a where the movement restricting portion 140b is provided and the portion where the movement restricting portion 140b is not provided are shown in FIGS. 6 and 7 in the first embodiment. The configuration is the same as that described above.

  Further, as described with reference to FIG. 4 in the first embodiment, the tube 110 is formed by joining two tube plates 110a and 110b by brazing. The joint portion between the two tube plates 110 a and 110 b is provided on the short side in the longitudinal direction in the flat cross section of the tube 110. For this reason, as shown in FIG. 9, the joint part of tube plate 110a, 110b and the movement control part 140b become a corresponding positional relationship.

  As shown in FIG. 9, since the two plate members overlap each other at the joined portion of the tube plates 110a and 110b, there is a triangular cross-section gap indicated by A (hereinafter referred to as “Δ portion”) surrounded by a broken line. To do. Since the tube 110 partitions the EGR gas passing through the inside and the cooling water passing through the outside, it is necessary to securely seal the Δ portion formed at the joint between the tube plates 110a and 110b.

  As described above, in the second embodiment, the joint portion of the tube plates 110a and 110b and the movement restricting portion 140b have a corresponding positional relationship. For this reason, as shown in FIG. 10, the brazing material 200 is easily held at the Δ portion formed at the joint portion of the tube plates 110a and 110b, and the brazing property of the Δ portion can be improved.

  According to the second embodiment described above, as in the first embodiment, the movement restricting portion 140b for preventing the tip portion of the tube 110 from protruding from the core plate 140 is provided in a part of the through hole 140a. The same effect as the first embodiment can be obtained.

  Further, according to the second embodiment, since the movement restricting portion 140b is provided on the short side in the longitudinal direction of the through hole 140a, both longitudinal ends of the flat cross section of the tube 110 are in contact with the movement restricting portion 140b. You will be in touch. For this reason, when the tube 110 is inserted into the through hole 140a, the tube 110 is not easily inclined, and the tube 110 can be easily positioned.

  In addition, according to the second embodiment, since the joint portion of the tube plates 110a and 110b and the movement restricting portion 140b have a corresponding positional relationship, the brazing material is easily held at the joint portion of the tube plates 110a and 110b. Thus, the tube plates 110a and 110b can be securely brazed. Thereby, the effect of reducing the leakage failure of the tube 110 can be obtained.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. In the third embodiment, the configuration of the core plate 140 is different from that in the first embodiment.

  As shown in FIG. 11, in the core plate 140 of the third embodiment, a pair of movement restricting portions 140b are provided at different positions in the longitudinal direction of the through hole 140a. In the third embodiment, a pair of opposing movement restriction portions 140b are provided at two locations on the long side of the through hole 140a, and four movement restriction portions 140a are provided on the long side of the through hole 140a. Yes. In the configuration shown in FIG. 11 as well, the cross section of the portion of the through hole 140a where the movement restricting portion 140b is provided and the portion where the movement restricting portion 140b is not provided are shown in FIGS. 6 and 7 in the first embodiment. The configuration is the same as that described above.

  According to the third embodiment described above, as in the first embodiment, the movement restricting portion 140b for preventing the distal end portion of the tube 110 from protruding from the core plate 140 is provided in a part of the through hole 140a. Therefore, the processing load when the core plate 140 is press-molded can be reduced. The same effect as in the first embodiment can be obtained.

  Further, according to the third embodiment, the movement restricting portions 140b are provided at a plurality of locations on the long side of the through hole 140a. For this reason, when the tube 110 is inserted into the through hole 140a, the tube 110 is not easily inclined, and the tube 110 can be easily positioned.

  Further, according to the third embodiment, by providing the movement restricting portion 140b on the long side of the through hole 140a of the core plate 140, the processing accuracy of the movement restricting portion 140b can be improved.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be variously modified as follows without departing from the spirit of the present invention. Further, the means disclosed in each of the above embodiments may be appropriately combined within a practicable range.

  (1) In each of the above embodiments, the movement restricting portion 140b is provided at two locations (first and second embodiments) or four locations (third embodiment) on the inner peripheral wall surface of the through hole 140a of the core plate 140. If at least one movement restricting portion 140b is provided on the inner peripheral wall surface of the through-hole 140a described in the example, the core plate 140 is prevented from protruding from the core plate 140 while preventing the tip portion of the tube 110 from protruding. The processing load at the time of press molding can be reduced.

  (2) In each of the above embodiments, the example in which stainless steel is used as the core plate 140 has been described. However, the present invention is not limited to this, and other materials such as aluminum may be used as the core plate 140.

10 Engine (Internal combustion engine)
110 Tube 120 Fin 130 Casing 140 Core plate 140a Through hole 140b Movement restricting portion

Claims (5)

An exhaust heat exchanger for exchanging heat between exhaust gas discharged from an internal combustion engine (10) and a cooling medium,
A plurality of tubes (110) through which the exhaust flows;
A casing (130) in which the tube (110) is housed and a cooling medium is circulated outside the tube (110);
A core plate (140) disposed at an end of the tube (110) inside the casing (130) and preventing the cooling water from flowing out of the casing (130);
The core blade (140) is provided with a through hole (140a) into which the tube (110) is inserted,
An exhaust heat exchanger characterized in that a movement restricting portion (140b) for restricting movement of the tube (110) in the axial direction is provided in a part of an inner peripheral portion of the through hole (140a). The tube (110) has a flat cross section, and the through hole (140a) has a shape corresponding to the flat cross section of the tube (110),
The exhaust heat exchanger according to claim 1, wherein the movement restricting portion (140b) is provided on a long side of the through hole (140a). The tube (110) has a flat cross section, and the through hole (140a) has a shape corresponding to the flat cross section of the tube (110),
The exhaust heat exchanger according to claim 1, wherein the movement restricting portion (140b) is provided on a short side of the through hole (140a).   The exhaust heat exchanger according to any one of claims 1 to 3, wherein the core plate (140) is made of stainless steel. The tube (110) is provided with a joint portion in which end portions of a plurality of plate members (110a, 110b) are overlapped,
The insertion portion of the tube (110) is located at a position corresponding to the movement restricting portion (140b) when the tube (110) is inserted into the through hole (140a). An exhaust heat exchanger according to any one of the above.

Images