JP2004270655A - Mesh-type spacing body, and exhaust manifold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mesh-type spacing body of excellent assembly efficiency and an exhaust manifold having the same at low cost. <P>SOLUTION: In a typical configuration of the mesh-type spacing body and the exhaust manifold having the same, a joined part 4c protruded on the outer side of an inner tube 4 can be avoided by providing a recessed part 6a at the position facing the joining part 4c with an upper half-split inner tube 4a and a lower half-split inner tube 4b of the inner tube joined with each other in the cylindrical mesh-spacing body 6 provided in a hollow part S between the inner tube 4 and the outer tube 5 in a meeting part A of the exhaust manifold 2 disposing the outer tube 5 with an upper half-split inner tube 5a and a lower half-split inner tube 5b joined with each other on the outer side of the inner tube 4 with the upper half-split inner tube 4a and the lower half-split inner tube 4b joined with each other. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention includes a mesh-shaped space holding member provided in a hollow portion of an assembly portion of an exhaust manifold for an automobile engine, mainly a thin-plate double-structured exhaust manifold, and for holding a space between an inner tube and an outer tube, and the same. It relates to an exhaust manifold.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an exhaust manifold having a thin plate double structure in which a hollow portion is provided between an inner pipe and an outer pipe as a heat insulating layer by air in order to insulate exhaust gas has been known as an exhaust manifold. In this exhaust manifold, an inner pipe and an outer pipe in which half pipes each having a shape for reducing back pressure are joined are used.
[0003]
However, in such an exhaust manifold where the inner pipe and the outer pipe are fitted with upper and lower thin plates, the overlapping part of the half pipes protrudes outward at the joint where the half pipes are joined, and the exhaust manifold gathering part The gap (hollow portion) between the inner tube and the outer tube is not uniform.
[0004]
Therefore, as shown in FIGS. 8 and 9, as a method for maintaining the interval between the inner tube 4 and the outer tube 5, a crescent-shaped half-mesh interval holding body 101 is sandwiched between hollow portions, and Maintaining the distance from the outer tube 5 is performed.
[0005]
[Problems to be solved by the invention]
However, the conventional mesh-shaped spacing member and the exhaust manifold including the same require a terminal treatment because the mesh-shaped spacing member is divided, so that the cost is higher than that of the cylindrical integral type. There was a problem of becoming. Further, when the mesh-shaped spacing member is assembled, the mesh-shaped spacing member becomes unstable, so that a set jig is required, and there has been a problem that the assembly efficiency is poor.
[0006]
In addition, when spot welding is performed to fix the half-mesh spacing member to the inner tube or the outer tube, the heat causes the mesh-shaped spacing member to be deformed so as to bloom (hereinafter referred to as a flower blooming phenomenon). . For this reason, the diameter dimension of the mesh-shaped spacing member becomes large, and when setting the inner tube and the outer tube, a large pressing force is required, and there is a problem that the assembling efficiency is poor.
[0007]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a mesh-shaped space holding member which can reduce costs and has a high assembling efficiency, and an exhaust manifold having the same.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a typical configuration of the mesh-shaped spacing member according to the present invention and an exhaust manifold including the same is such that a half pipe is joined to the outside of an inner pipe formed by joining a half pipe. In a cylindrical mesh spacing member provided in a hollow portion between the inner pipe and the outer pipe in a collection portion of the exhaust pipe in which the outer pipe is disposed, a joining portion in which half pipes of the inner pipe are joined A concave portion is provided at a position facing the inner tube so that a joint portion protruding outside the inner tube can be avoided.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
[First embodiment]
A first embodiment of a mesh-shaped spacing member and an exhaust manifold including the same according to the present invention will be described with reference to the drawings. 1 is a diagram showing an exhaust system using an exhaust manifold, FIG. 2 is a cross-sectional view of the exhaust manifold, FIG. 3 is an explanatory diagram of a method for manufacturing a mesh-shaped spacing member, and FIG. 4 is an explanatory diagram of assembling of the exhaust manifold. .
[0010]
As shown in FIG. 1, an exhaust manifold 2 that combines two exhaust ports into one is attached to the engine 1. A catalyst (not shown) for purifying exhaust gas is provided in the exhaust system, and it is known that the efficiency of the catalyst is better as the temperature of the exhaust gas is higher. Therefore, it is necessary to guide the exhaust gas to the catalyst with a reduced temperature drop.
[0011]
As shown in FIG. 2, the exhaust manifold 2 includes an inner tube 4, an outer tube 5, and a mesh-shaped spacing member 6, and is formed by a hollow portion S that is an air layer between the inner tube 4 and the outer tube 5. The exhaust gas passing through the inner pipe 4 is insulated and discharged.
[0012]
The inner pipe 4 is assembled in a substantially cylindrical cross section by joining an upper half inner pipe 4a and a lower half inner pipe 4b at a joint 4c. The upper half inner tube 4a and the lower half inner tube 4b are formed in a substantially semicircular cross section by pressing a thin plate made of a heat-resistant material such as a stainless steel plate. The joint 4c is welded so as to protrude outward to reduce the back pressure of the exhaust gas discharged from the inside of the inner pipe 4.
[0013]
The outer tube 5 is assembled into a substantially cylindrical cross section by joining an upper half outer tube 5a and a lower half outer tube 5b at a joint 5c. The upper half-split outer tube 5a and the lower half-split outer tube 5b are formed by pressing a thin plate made of a heat-resistant material such as a stainless steel plate into a substantially semicircular cross section having a larger curvature than the inner tube 4.
[0014]
The mesh-shaped spacing member 6 is a mesh woven in a tubular shape, and is interposed between the inner tube 4 and the outer tube 5 between the inner tube 4 and the outer tube 5 of the collecting portion A of the exhaust manifold 2. The distance between the tubes 5 is kept constant. Since the mesh spacing member 6 is in contact with the inner tube 4 and the outer tube 5, heat conduction can be reduced as much as possible, and a thin linear stainless steel or the like is used so that the mesh spacing member 6 itself is not deformed by heat. It is formed of a heat-resistant mesh.
[0015]
A concave portion 6a is provided at a position facing the joint portion 4c of the mesh-shaped spacing member 6, and the mesh-shaped spacing member 6 is formed so as not to contact the joint portion 4c protruding outside the inner tube 4.
[0016]
Next, a method for manufacturing the mesh-shaped spacing member 6 will be described. As shown in FIG. 3, the mesh-shaped spacing member 6 is formed by a base mold 7 and a male mold 11.
[0017]
The base mold 7 includes a mold 8 having a through hole 8a and a core mold 9 having a core 10 that enters the through hole 8a. The through hole 8a is formed with a diameter approximately equal to the inner diameter of the outer tube 5, and the core 10 is formed with a diameter approximately equal to the outer diameter of the inner tube 4. The core 10 has two extruded portions 10a so as to be point-symmetrical on the outer peripheral surface, and the extruded portions 10a are configured to be able to enter and exit from the core 10.
[0018]
First, as shown in FIG. 3A, the core 10 is inserted into the through hole 8a with the extruded portion 10a retracted into the core 10, and the core 10 is covered between the through hole 8a and the core 10. The mesh 12 is inserted into a cylindrical shape. Next, the extruded portion 10a is made to protrude from the core 10 to form a recess 6a in the mesh 12.
[0019]
Then, as shown in FIG. 3 (b), the mesh 12 having the recess 6a is taken out of the base mold 7, inserted into a compression female mold (not shown), and compressed in the longitudinal direction with a male mold 11 to form a mesh. The spacing member 6 is formed.
[0020]
Next, assembling of the exhaust manifold 2 will be described. First, as shown in FIGS. 4 (a) and 4 (b), the inner pipe 4 is formed by welding the upper half inner pipe 4a and the lower half inner pipe 4b at the joint 4c. Next, the mesh-shaped spacing member 6 is fitted to the inner pipe 4 of the collecting part A of the exhaust manifold 2. At this time, the joining portion 4c and the concave portion 6a are positioned so as to face each other, so that the mesh-shaped spacer 6 can be prevented from contacting the joining portion 4c. Then, the mesh-shaped spacing member 6 is fixed to the outer periphery of the inner pipe 4 by spot welding.
[0021]
Subsequently, as shown in FIGS. 4C and 2, the upper half outer tube 5 a and the lower half outer tube 5 b are brought into contact with the outer peripheral surface of the mesh-shaped spacing member 6, and the mesh-shaped spacing member 6 is formed. Is pressed and compressed, the upper half outer tube 5a and the lower half outer tube 5b are welded at the joint 5c to form the outer tube 5, and the assembly of the exhaust manifold 2 is completed.
[0022]
As described above, the mesh-shaped spacing member 6 has a cylindrical shape, and is provided with the concave portion 6a at a position facing the joint portion 4c where the upper half inner tube 4a and the lower half inner tube 4b of the inner tube 4 are joined. It was configured not to come into contact with the joint 4c protruding outside the tube 4.
[0023]
By providing the recess 6a in this manner, the outer tube 5 can be prevented from being pushed by the joint 4c via the mesh-shaped spacing member 6, and the distance between the inner tube 4 and the outer tube 5 can be kept constant. .
[0024]
In addition, since the mesh-shaped spacing member 6 is formed in a cylindrical shape, the terminal treatment is not required, the cost can be suppressed, and the mesh can be set in the inner pipe 4 without a setting jig. The work efficiency of assembly can be improved.
[0025]
Further, when the mesh-shaped spacing member 6 is fixed to the inner tube 4 by spot welding, a flower bloom phenomenon due to heat is unlikely to occur, and the mesh-shaped spacing member 6 is less deformed than the split type spacing member. Therefore, when setting the outer tube 5, a large pressing force is not required, and the working efficiency can be improved.
[0026]
[Second embodiment]
Next, a second embodiment of a mesh-shaped spacing member and an exhaust manifold provided with the same according to the present invention will be described with reference to the drawings. FIG. 5 is an explanatory diagram of the mesh-shaped spacing member according to the present embodiment. The same parts as those in the first embodiment will be denoted by the same reference numerals, and description thereof will be omitted.
[0027]
As shown in FIG. 5, a mesh-shaped spacing member 26 of the present embodiment is obtained by forming concave and convex portions in the recess 6a of the mesh-shaped spacing member 6 of the first embodiment.
[0028]
In the mesh-shaped spacing member 26, the concave portion 26a is formed longer than the concave portion 6a of the first embodiment, and the concave portion 26a is contracted in the circumferential direction to form irregularities in the radial direction. By extending the concave portion 26a in the circumferential direction, the diameter of the mesh-shaped spacing member 26 can be increased until the concave and convex portions of the concave portion 26a disappear. Therefore, the diameter of the mesh-shaped spacing member 26 can be changed by the length of the unevenness of the concave portion 26a, and can be expanded and contracted in accordance with the outer diameter of the inner pipe 4 of the collecting portion A of the exhaust manifold 2.
[0029]
Thereby, when the mesh-shaped spacing member 26 is set in the inner tube 4, the concave portion 26a can be expanded and contracted in the radial direction to absorb the dimensional tolerance of the outer diameter of the inner tube 4, thereby facilitating the assembly and improving the work efficiency. Can be better.
[0030]
[Third embodiment]
Next, a third embodiment of a mesh-shaped spacing member and an exhaust manifold provided with the same according to the present invention will be described with reference to the drawings. FIG. 6 is an explanatory diagram of the mesh before molding according to the present embodiment. The same parts as those in the first embodiment will be denoted by the same reference numerals, and description thereof will be omitted.
[0031]
The mesh-shaped spacing member according to the present embodiment is formed by forming a concave portion in a low-density mesh, inserting the recessed portion into a compression female mold (not shown), and compressing with a male mold 11 to increase the density. In the step of forming the holding body, the mesh 37 is formed using a mesh 37 in which the mesh density of the portion 37a serving as the concave portion 6a of the mesh 37 before forming is smaller than that of the other portions 37b instead of the mesh 12 of the first embodiment. It was done.
[0032]
As shown in FIG. 6, the mesh-shaped spacing member is formed by a manufacturing process similar to that of the first embodiment, using a mesh 37 instead of the mesh 12 of the first embodiment. The mesh 37 is obtained by coarsely knitting the mesh only in the portion 37a to be the concave portion 6a and making the mesh density smaller than that of the other portion 37b.
[0033]
As described above, when the concave portion 6a of the mesh-shaped spacing member 6 is formed, the mesh density of the portion 37a serving as the concave portion 6a is made smaller than that of the other portion 37b in advance, so that the extruded portion 10a projecting from the core 10 Can be reduced, and the concave portion 36a can be easily formed.
[0034]
[Fourth embodiment]
Next, a fourth embodiment of a mesh-shaped spacing member and an exhaust manifold including the same according to the present invention will be described with reference to the drawings. FIG. 7 is an explanatory diagram of the method for manufacturing the mesh-shaped spacing member according to the present embodiment. The same parts as those in the first embodiment will be denoted by the same reference numerals, and description thereof will be omitted.
[0035]
As shown in FIG. 7, the mesh-shaped spacing member 36 according to the present embodiment is formed by using a male mold 38 instead of the male mold 11 of the first embodiment. The male mold 38 is provided with a relief portion 38a in the axial direction of the mesh 12 at a portion of the mesh-shaped spacing member 36 that contacts the concave portion 36a.
[0036]
The mesh 12 having the concave portion formed therein is inserted into a compression female mold (not shown) in the same manner as in the first embodiment, and is compressed in the longitudinal direction with a male mold 38 to form a mesh-shaped spacing member 36. The mesh-shaped spacing member 36 thus formed is formed such that the axial end of the concave portion 36a protrudes from another portion to the shape of the relief portion 38a because the concave portion 36a is not compressed by the relief portion 38a. You.
[0037]
In the present embodiment, the escape portion 38a is provided in the male mold 38, but the escape portion may be provided in the female mold (not shown).
[0038]
As described above, the mesh-shaped spacing member 36 was formed by the male mold 38 having the escape portion 38a in the axial direction of the mesh 12 at a portion in contact with the concave portion 36a of the mesh-shaped spacing member 36. This prevents the concave portion of the mesh-shaped spacing member from being deformed by the compression by the male type, thereby making it possible to reliably prevent the mesh-shaped spacing member from coming into contact with the joint 4c.
[0039]
【The invention's effect】
As described above, the mesh-shaped spacing member has a cylindrical shape, and a concave portion is provided at a position facing the joint portion where the half pipes of the inner tube are joined, so that the meshed spacer does not contact the joint portion protruding outside the inner tube. Configured. Providing the concave portion in this way prevents the outer tube from being pushed by the joint portion via the mesh-shaped spacing member, and can keep the distance between the inner tube and the outer tube constant.
[0040]
In addition, since the mesh-shaped spacing member has a cylindrical shape, there is no need for terminal treatment, cost can be reduced, and it can be set on the inner pipe without a setting jig, and the work of assembling the exhaust manifold Efficiency can be improved.
[0041]
Further, when the mesh-shaped spacer is fixed to the inner tube by spot welding, flower bloom due to heat is less likely to occur, and the mesh-shaped spacer is less deformed than the split type spacer. Therefore, when setting the outer tube, a large pressing force is not required, and the working efficiency can be improved.
[0042]
Further, the concave portion has an unevenness in the radial direction, and is configured to expand and contract in accordance with the outer diameter of the collecting portion of the inner tube. Accordingly, when the mesh-shaped spacing member is set in the inner tube, the concave portion can be expanded and contracted to absorb the dimensional tolerance of the outer diameter of the inner tube, and the assembling can be facilitated to improve the working efficiency.
[0043]
In the process of inserting a low-density mesh into a compression female mold and compressing it with a male mold to increase the density to form a mesh-shaped spacing member, the mesh density of a portion that becomes a concave portion of the mesh before molding. Was molded using a material smaller than the other parts. Thereby, the concave portion can be formed with a small pressing force, and the concave portion can be easily formed.
[0044]
The male type or the female type has an escape portion in the axial direction, and the axial end of the concave portion of the mesh-shaped spacing member is formed in the shape of the escape portion. This prevents the concave portion of the mesh-shaped spacing member from being deformed by the compression by the male mold, and reliably prevents the mesh-shaped spacing member from contacting the joint of the inner tube.
[Brief description of the drawings]
FIG. 1 is a diagram showing an exhaust system using an exhaust manifold.
FIG. 2 is a cross-sectional view of an exhaust manifold.
FIG. 3 is an explanatory view of a method for manufacturing a mesh-shaped spacing member.
FIG. 4 is an explanatory view of assembling an exhaust manifold.
FIG. 5 is an explanatory diagram of a mesh spacing member according to a second embodiment.
FIG. 6 is an explanatory diagram of a mesh before forming according to a third embodiment.
FIG. 7 is an explanatory diagram of a method for manufacturing a mesh-shaped spacing member according to a fourth embodiment.
FIG. 8 is a longitudinal sectional view of a conventional exhaust manifold.
FIG. 9 is an explanatory view of assembling a conventional exhaust manifold.
[Explanation of symbols]
A: Collecting part S: Hollow part 1 ... Engine 2 ... Exhaust manifold 4 ... Inner tube 4a ... Upper half inner tube 4b ... Lower half inner tube 4c ... Joint 5 ... Outer tube 5a ... Upper half inner tube 5b ... Lower half inner tube 5c Joining part 6 Mesh spacing member 6a Depressed part 7 Base mold 8 Mold 8a ... Through hole 9 Core mold 10 Core 10a Extruded part 11 Male mold 12 Mesh 26 Mesh-shaped space holding member 26a ... concave portion 36 ... mesh-shaped space holding member 36a ... concave portion 37 ... mesh 37a ... portion 37b ... other portion 38 ... male type 38a ... escape portion

Claims (5)

A cylindrical shape provided in a hollow portion between the inner pipe and the outer pipe in a collection part of the exhaust pipe in which an outer pipe formed by joining the half pipes is disposed outside the inner pipe formed by joining the half pipes. A mesh spacing member of
A mesh-shaped spacing member characterized in that a concave portion is provided at a position facing a joint portion where the half tubes of the inner tube are joined, so that a joint portion protruding outside the inner tube can be avoided. . 2. The mesh-shaped spacer according to claim 1, wherein the concave portion has irregularities in a radial direction, and expands and contracts in accordance with an outer diameter of the collecting portion of the inner tube. 3. In the step of inserting the low-density mesh into the compression female mold and compressing it with a male mold to increase the density to form the mesh-shaped spacing member, the mesh density of the portion of the mesh before molding that becomes the concave portion The mesh-shaped spacing member according to claim 1 or 2, wherein the mesh-shaped spacer is formed using a member having a smaller size than other portions. In the step of inserting a low-density mesh into a compression female mold and compressing with a male mold to increase the density to form a mesh-shaped spacing member, the male or female mold has a relief in the axial direction. The mesh-shaped spacing member according to any one of claims 1 to 3, wherein an axial end portion of the concave portion is formed in a shape of the relief portion. An exhaust manifold, wherein the mesh-shaped spacing member according to any one of claims 1 to 4 is provided between an inner pipe and an outer pipe of the collecting section of the exhaust pipe.

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