JP2015034511A - Pipe material junction structure for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve remarkably an anti-bending characteristic without accompanying any trouble in processing work at a structure in which one end part of a pipe material is brazed to a supporting member such as a flange plate and the like.SOLUTION: A fitting part 16 fitted into a fitting hole 15 of a flange plate 12 in an EGR upper pipe 11 is separated into a fixed part 16a fixed to the flange plate 12 with solder 18 and a non-fixed part 16b with a clearance 19 being opened outside an outer circumferential surface. An annular concave part 20 is formed at an end part near the non-fixed part 16b in the fixed part 16a, and the annular concave part 20 is an accumulation part for solder 18. When a bending force acts against the EGR upper pipe 11, a stress is at first concentrated at a joint part of the fixed part 16a in the non-fixed part 16b and then the EGR upper pipe 11 abuts against an opening edge 15a of the fitting hole 15, thereby the stress concentrated location is moved. The stress concentrated location can be dispersed, resulting in that an anti-bending characteristic can be remarkably improved.

Description

  The present invention relates to a structure for fixing a metal pipe material to a plate-like support member in an internal combustion engine.

  Many metal pipe materials are used in internal combustion engines. As a joint structure for this pipe material, one end of the pipe material is inserted into a mounting hole formed in a support member, and the pipe material is spread over the entire circumference. The support member may be brazed or welded.

  A problem when the pipe material is brazed or welded to the support member is that the bending force acting on the pipe material is concentrated on the joint portion to the support member. Conventionally, this has been dealt with by increasing the strength of the joint portion of the pipe member to the support member and its peripheral portion.

  As an example, Patent Document 1 discloses that when an intake manifold is joined to a flange or the like, several ribs (protrusions) projecting outward are protruded in the circumferential direction at a portion of the exposed portion of the intake manifold close to the flange. It is described that each rib is brought into contact with a surface such as a flange. Further, in Patent Document 2, as one structure of the intake manifold, one end portion of the pipe material is formed in a thick portion, and about half of the thick portion is inserted into a flange or the like, and the exposed portion of the thick portion is exposed. It is described that the part is brazed to a flange or the like.

JP 2000-310167 A JP 2001-020816 A

  When the pipe material is joined to a support member such as a flange, it is inevitable that stress concentrates around the joint itself. Patent Documents 1 and 2 attempt to reinforce the portion where the stress is concentrated, but in any case, the processing is very troublesome, and the application conditions such as the wall thickness are limited, so that it is versatile. There is a problem of lacking.

  Further, in the case of Patent Document 1, the formation of a rib may cause a crack, and a new problem is expected to occur. On the other hand, in the case of Patent Document 2, there is a possibility that stress concentrates on the boundary between the thick part and the thin part, and there is a possibility that the stress concentration part is merely shifted.

  The present invention has been made to improve such a current situation, and aims to provide a pipe material joining structure excellent in versatility and bending resistance.

  In the present invention, one end portion of the metal pipe material is formed as an insertion portion inserted into the mounting hole of the support member, and at least a portion of the pipe material excluding the insertion portion is exposed outside the surface of the support member. (In the present invention, the pipe material may protrude from the back side of the support member.).

  According to claim 1, in the basic configuration, the fitting portion of the pipe material is located on the back surface side of the support member with the boundary between one end and the other end of the fitting portion as the boundary. It is divided into a fixed part brazed to the inner surface of the hole and a non-fixed part which is located on the surface side of the support member and is in a free state, between the non-fixed part and the inner peripheral surface of the mounting hole Further, when the pipe member is subjected to a bending action, there is a gap that allows the non-fixed portion to elastically deform and then hit the opening edge of the mounting hole.

  The present invention can be developed in various ways. As an example, in the invention of claim 2, in claim 1, the solder melted at the time of brazing is prevented from flowing to the non-fixed portion side in either one or both of the pipe material and the mounting hole. A brazing stopper is provided. Further, in the invention of claim 3, as a preferred development example of claim 2, the brazing portion is an annular recess formed in the fitting portion of the pipe material.

  In the present invention, when a bending force acts on the exposed portion of the pipe material, the stress first concentrates on the boundary portion with the fixed portion of the non-fixed portion in the fitting portion, and the fitting portion is bent to open the attachment hole. When hitting the edge, stress is then concentrated on the part hitting the opening edge. And in the state where the pipe material hits the opening edge of the mounting hole, the bending force acting on the pipe material has already been greatly reduced by the deformation of the fitting portion, so the size is said to be concentrated while stress is concentrated Remarkably low.

  In other words, in the present invention, the stress concentration points are dispersed in two places. This prevents excessive stress from concentrating on a specific point even when a large bending force acts on the pipe material, resulting in high resistance. Exhibits bending properties. In other words, instead of dealing with reinforcement, the load is applied using the elastic deformation function of the pipe material. Therefore, it is not necessary to perform complicated processing on the pipe material and the mounting hole. Therefore, it is widely applicable to various pipe materials and is excellent in versatility.

  If the invention of claim 2 is adopted, the end of the brazing can be regulated by the brazing stopper portion, so that it is possible to prevent poor bonding and to stabilize the quality.

  In particular, when the annular recess is formed in the insertion portion as in the third embodiment as the brazing stopper portion, the melted wax is held in the annular recess by the surface tension because the annular recess becomes the reservoir portion of the wax. Although it is a simple process, there is an advantage that the solder can be accurately prevented from flowing to the non-fixed portion. Moreover, since the surface area of the insertion portion is increased by providing the annular recess, it is possible to contribute to an increase in bonding strength.

  Furthermore, when a bending force acts on the exposed portion of the pipe material, the bending force reaches the annular recess, so that the area of the portion where the stress is concentrated at the beginning of bending can be widened. Bending characteristics can be further improved.

(A) is a front view of an embodiment of the first embodiment. It is a side view. (A) is a plan view, (B) is a cross-sectional view taken along line BB of (A), (C) is a cross-sectional view taken along line CC of (B), and (D) is a partially enlarged view of (C). . It is principal part sectional drawing of other embodiment.

(1) Description of Structure Next, an embodiment of the present invention will be described with reference to the drawings. First, the structure will be described. The present embodiment is applied to a joint structure of pipe materials for EGR gas in a vehicle internal combustion engine. This will be described below.

  The internal combustion engine of the present embodiment includes an engine body having a cylinder block 1 and a cylinder head 2 fixed on the upper surface thereof. The engine body is horizontally oriented with a crankshaft (not shown) in a left-right longitudinal posture. It is mounted on the vehicle. The internal combustion engine of the present embodiment has three cylinders, and an exhaust manifold 3 is fixed to the front surface 2a of the cylinder head 2, and a cylindrical catalyst case 4 that is vertically long and longitudinal is welded to a downward collecting pipe in the exhaust manifold 3.

  The lower end portion of the catalyst case 4 is a narrowed lower taper portion 4a. A downward joint pipe 5 is welded to the lower taper section 4a, and the joint pipe 5 is formed of a metal plate support bracket 6 and a support stay ( It is fixed to the cylinder block 1 via a not shown). An exhaust pipe 7 is connected to the joint pipe 5 from below.

  An EGR cooler 9 containing an EGR main pipe 8 is connected to the lower taper portion 4a of the catalyst case 4 via an L-shaped pipe 9, and the upper end of the EGR main pipe 8 faces the direction of the cylinder head 2. In general, an EGR upper pipe 11 that is long in the front-rear direction and bent in an inverted L shape in a side view is connected. The EGR upper pipe 11 is connected to the front surface 2a of the cylinder head 2 via the flange plate 12 in two upper and lower sides. It is fixed with bolts 13. The EGR cooler 9 is connected to a cooling water injection pipe 14a and a discharge pipe 14b.

  In the present embodiment, the present invention is applied to the joint structure between the EGR upper pipe 11 and the flange plate 12, and the details thereof will be described with reference to FIGS. The EGR upper pipe 11 is made of a stainless steel round pipe material, and the tip (one end) of the EGR upper pipe 11 is fitted into the mounting hole 15 provided in the flange plate 12 as shown in FIGS. ing. Therefore, most of the EGR upper pipe 11 is an exposed portion that protrudes outside the surface 12 a of the flange plate 12.

  Accordingly, one end of the EGR upper pipe 11 has a fitting portion 16 inserted into the attachment hole 15, but the inner diameter D1 of the attachment hole 15 is slightly larger than the outer diameter D2 of the EGR upper pipe 11. ing. The insertion portion 16 is located on the back surface 12b side of the flange plate 12 with a boundary 17 positioned between one end and the other end thereof, and is fixed to the flange plate 12 with a brace 18. And a non-fixed portion 16 b that is located on the surface 12 a side of the flange plate 12 and that has a gap 19 between the inner peripheral surface of the mounting hole 15. Note that in FIG. 3D, the gap 19 is exaggerated and displayed with priority given to ease of understanding.

  When a downward load is applied to the EGR upper tube 11, the fitting portion 16 also bends downward. However, the size of the gap 19 and the non-fixed portion so that the EGR upper tube 11 contacts the opening edge 15 a of the mounting hole 15 within the range of elastic deformation. The width dimension in the axial direction of 16b is set. Note that the dimension of the gap 19 and the width dimension of the non-fixed portion 16b are proportional to each other. When the dimension of the gap 19 is small, the width dimension of the non-fixed portion 16b may be small.

  A portion adjacent to the boundary 17 in the fixed portion 16a is formed with an annular recess 20 having an arc-shaped cross section that opens radially outward as an example of the brazing portion described in the claims. The annular recess 20 is filled. The outer diameter D2 of the fitting portion 16 remains the material diameter of the EGR upper pipe 11, and therefore the thickness of the wax 18 is the same as the size of the gap 19 except for the annular recess 20. The annular recess 20 can be easily processed by pressing a roller from the outside (the annular recess 20 may be formed in a state before the EGR upper tube 10 is bent).

(2) Summary In the above configuration, as shown by the black arrow in FIG. 2, the catalyst case 4 is exposed to high-temperature exhaust gas, so that it greatly expands so as to extend downward as the engine starts. On the other hand, since the inflow temperature of the exhaust gas to the EGR cooler 9 is low and the EGR cooler 9 is cooled by the cooling water, the EGR cooler 9 does not expand as much as the catalyst case 4, and therefore, With the start of engine operation, the EGR upper pipe 11 is pulled downward through the EGR cooler 9 as shown by a white arrow in FIG. That is, a downward bending force with the joint to the flange plate 12 as a fulcrum acts on the EGR upper pipe 11 with the start of operation of the engine.

  In the present invention, if the maximum angle at which the EGR upper tube 11 rotates downward (bends downward) is θ1, the fixed portion of the fitting portion 16 is fixed within a certain range of angle θ1 after starting downward rotation. The stress concentrates on the connecting portion between the portion 16a and the non-fixed portion 16b, and the bending of the EGR upper pipe 11 is allowed mainly due to the deformation of the non-fixed portion 16b to the fixed portion 16a. θ2 is preferably set to about half of θ1.

  Next, during the downward rotation of the EGR upper pipe 11, the boundary between the non-fixed portion 16 b and the exposed portion of the EGR upper pipe 11 abuts on the opening edge 15 a of the attachment hole 15, and the EGR upper pipe 11 is attached to the attachment hole 15. It shifts to the bending with the opening edge 15a of the opening as a fulcrum. That is, the stress concentration location shifts from the connecting portion of the non-fixed portion 16b to the fixed portion 16a to the boundary portion between the non-fixed portion 16b and the exposed portion.

  Since the stress concentration points are dispersed in two places in this way, the concentrated stress can be remarkably reduced, so that the breaking strength against bending can be significantly improved. In addition, the EGR upper pipe 11 is bent and deformed as a whole, and is not bent only at the stress concentration portion. When the annular recess 20 is formed in the insertion portion 16 as in the embodiment, the surface area of the insertion portion 16 is increased, so that the bonding strength can be improved, and the bending portion 16 is easily bent so that the bending strength can be further improved. is there.

  In the brazing process, for example, a paste-like brazing material is applied to the inner peripheral surface of the attachment hole 15 and then the insertion portion 16 of the EGR upper pipe 11 is inserted into the attachment hole 15. The brazing material is filled in the gap between the fixing portion 16a and the mounting hole 15, and then the whole is heated to melt the brazing material and then solidify. As a result, the phenomenon of accumulating in the annular recess 20 is reddened, so that it is possible to prevent the wax from flowing toward the non-fixed portion 16b and to regulate the position of the wax 18.

  In the brazing step, instead of previously applying a brazing material to the inner surface of the mounting hole 15 or the outer peripheral surface of the fixing portion 16a, the melted brazing is put in the gap between the fixing portion 16a and the mounting hole 15. It may be infiltrated.

(3). Other Embodiments / Others FIG. 4 shows another example of the brazing stopper that regulates the end of the brazing. Among these, in 2nd Embodiment shown to (A), the outward cyclic | annular protrusion 21 is formed in the boundary part of the fixing | fixed part 16a and the non-fixed part 16b among the insertion parts 16 in the EGR upper pipe 11. FIG.

  On the other hand, in the third embodiment shown in (B), an inward annular protrusion 22 is formed on the inner peripheral edge of the mounting hole 15. Instead of the annular protrusion 22, an inward annular groove may be formed on the inner peripheral surface of the attachment hole 15.

  The present invention can be embodied in various ways other than the above-described embodiment. For example, the application target is not limited to the EGR pipe, and can be applied to joining various pipe materials such as an oil feeding pipe, an intake air feeding pipe, a fuel pipe, a blow-by gas pipe, and a member supporting pipe material. It is also possible to form a plurality of annular recesses or annular projections in the non-fixed part or the exposed part or both of the pipe material, and to make the non-fixed part or the exposed part or both have a bellows structure. The support member to which the pipe material is joined need not be a plate material such as a flange plate, and may be in any form as long as brazing is possible.

  The present invention can be embodied in the joining of EGR pipes. Therefore, it can be used industrially.

2 Cylinder head 3 Exhaust manifold 4 Catalyst case 9 EGR cooler 10 EGR upper pipe as an example of pipe material 11 Flange plate as an example of support member 15 Mounting hole 16 Insertion part 16a Fixing part 16b Non-fixing part 17 Boundary 18 Low 19 Gap

Claims (3)

One end portion of the metal pipe material is formed as an insertion portion inserted into the mounting hole of the support member, and at least a portion of the pipe material excluding the insertion portion is exposed outside the surface of the support member. There,
The fitting portion of the pipe material is located on the back surface side of the support member at the boundary between one end and the other end of the fitting portion, and is fixed to the inner surface of the attachment hole, When the pipe material is subjected to a bending action between the non-fixed part and the inner peripheral surface of the mounting hole, which is located on the surface side of the support member and is in a free state. There is a gap that allows the non-fixed part to elastically deform and then hit the opening edge of the mounting hole.
Pipe material joint structure for internal combustion engines. In either one or both of the pipe material and the mounting hole, a brazing stopper is provided that prevents the molten solder during brazing from flowing to the non-fixed portion.
The pipe material joint structure for an internal combustion engine according to claim 1. The brazing part is an annular recess formed in the fitting part of the pipe material,
The pipe material joint structure for an internal combustion engine according to claim 2.

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