JP2017057745A - Cover structure of exhaust pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress occurrence of an abnormal noise in a cover structure of an exhaust pipe, in which plural covers are arranged along the longitudinal direction of the exhaust pipe and are joined to the exhaust pipe in a manner of covering at least a part of the exhaust pipe along the circumferential direction.SOLUTION: Covers 15, 16 are comprised of pairs of cover halves 17, 18; 19, 20 which are formed semicircular in cross sectional shape. One 15 of the pair of covers 15, 16 adjoining in the longitudinal direction of the exhaust pipe 13 is configured to have: a cylindrical cover main part 22 which covers the whole circumference of the exhaust pipe 13 to form an annular gap with the outer periphery of the exhaust pipe 13 and is welded to the exhaust pipe 13 at plural places or one place along the longitudinal direction of the exhaust pipe 13; and a diameter-reduced cylinder part 23 which is provided consecutively to one axial end of the cover main part 22 to slidingly contact with the outer periphery of the exhaust pipe 13 and is slidably fitted in the other 16 of the pair of covers 15, 16.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an exhaust pipe cover structure in which a plurality of covers arranged along the longitudinal direction of the exhaust pipe are joined to the exhaust pipe so as to cover at least a part along the circumferential direction of the exhaust pipe. .

  For the purpose of protecting an exhaust pipe that guides exhaust gas from an internal combustion engine for vehicles or preventing thermal damage from the exhaust pipe, the exhaust pipe may be covered with a cover that is joined to the exhaust pipe by welding or the like. In this case, if the exhaust pipe is covered with a long cover along the exhaust pipe, the vibration of the exhaust pipe increases, and abnormal noise is transmitted to the user. In order to prevent this vibration, it is conceivable to increase the joint area such as welding, but there is a problem that thermal distortion occurs. In addition, both ends in the circumferential direction of a pair of half-split covers may be fastened with bolts to cover the entire circumference of the exhaust pipe, but the number of parts increases and the cover becomes larger in the radial direction of the exhaust pipe. End up.

  On the other hand, a plurality of covers covering a part of the outer periphery of the exhaust pipe are welded to the outer periphery of the exhaust pipe, and a protrusion provided on one end of the cover that is adjacent to each other in the longitudinal direction of the exhaust pipe, It is a patent that is fitted in a fitting hole provided in the other end of the other cover to suppress an increase in the number of parts and avoid an increase in the size of the cover in the radial direction of the exhaust pipe. It is known from document 1.

JP 2012-167469 A

  However, in the one disclosed in Patent Document 1, one end of the pair of covers adjacent to each other and the other end of the other cover are in contact with each other without contacting the exhaust pipe. There is a possibility that abnormal noise due to vibration will increase. Further, a folded portion for preventing intrusion of mud or the like into the fitting hole is formed on the other end portion of the other cover so as to protrude outward, and the cover is exhausted only at the folded portion. It will increase in size in the radial direction of the tube.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an exhaust pipe cover structure capable of suppressing the generation of abnormal noise due to vibration.

  In order to achieve the above object, according to the present invention, a plurality of covers arranged along the longitudinal direction of the exhaust pipe are joined to the exhaust pipe so as to cover at least a part along the circumferential direction of the exhaust pipe. In the exhaust pipe cover structure, the cover is composed of a pair of cover halves having a semicircular cross-sectional shape, and one of the pair of covers adjacent in the longitudinal direction of the exhaust pipe is an outer periphery of the exhaust pipe. A cylindrical cover main portion that covers the entire circumference of the exhaust pipe so as to form an annular gap between the cylindrical cover and is welded to the exhaust pipe at a plurality of places or at one place along the longitudinal direction of the exhaust pipe; The cover main portion is configured to have a reduced-diameter cylindrical portion that is continuously provided at one end portion in the axial direction, is in sliding contact with the outer periphery of the exhaust pipe, and is slidably fitted into the other of the pair of covers. This is the first feature.

  Further, the present invention, in addition to the configuration of the first feature, the outer diameter of one of the cover main portions of a pair of covers adjacent in the longitudinal direction of the exhaust pipe, and the maximum outer diameter of the other cover, A second feature is that they are set to the same value.

  Furthermore, in addition to the configuration of the first or the second feature, the present invention is configured such that the circumferential ends of the pair of cover halves constituting the cover are simultaneously welded to the outer periphery of the exhaust pipe. A third feature is that welded portions are formed at the same location in the longitudinal direction of the exhaust pipe.

  According to the first feature of the present invention, a cover formed of a pair of cover halves is welded to two circumferential positions of the exhaust pipe at a plurality of places or one place along the longitudinal direction of the exhaust pipe so that the entire circumference of the exhaust pipe is obtained. One axial end of a pair of covers adjacent in the longitudinal direction of the exhaust pipe is slidably fitted to the outer periphery of the exhaust pipe and is slidably fitted into the other adjacent cover. It absorbs thermal expansion without fail, suppresses the generation of noise due to vibration at the overlapping parts of adjacent covers, and reduces the stress on the welded part by reducing the load on the welded part by suppressing the spread in the radial direction. And durability can be improved.

  Further, according to the second feature of the present invention, since the outer diameter of one cover main part of the pair of covers adjacent in the longitudinal direction of the exhaust pipe is the same as the maximum outer diameter of the other cover, It is possible to suppress the spread in the area and to reduce the size of the cover in the radial direction.

  Furthermore, according to the third feature of the present invention, since the welded portions formed at the circumferential ends of the pair of cover halves are welded simultaneously to the outer periphery of the exhaust pipe, the accuracy of the welded portion is high. Positioning can be performed in one step, and manufacturing becomes easy.

It is a side view which shows a part of exhaust system of an internal combustion engine. FIG. 2 is an enlarged view taken along arrow 2 in FIG. 1. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. It is a perspective view which shows the cover and exhaust pipe which were decomposed | disassembled. FIG. 5 is a sectional view taken along line 5-5 of FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 5. First, in FIG. 1, an exhaust system 11 of a vehicle internal combustion engine includes a flange 12 connected to a cylinder head of the internal combustion engine. Includes an exhaust pipe 13 provided at the upstream end portion and an exhaust muffler 14 connected to the downstream end portion of the exhaust pipe 13.

  At least a part of the exhaust pipe 13 along the circumferential direction is covered with a plurality of covers that are arranged along the longitudinal direction of the exhaust pipe 13 and joined to the exhaust pipe 13. Then, the 1st and 2nd covers 15 and 16 which adjoin along the longitudinal direction of the exhaust pipe 13 are joined to the outer periphery of the said exhaust pipe 13 so that the perimeter of the intermediate part of the said exhaust pipe 13 may be covered.

  2 to 4, the first cover 15 is composed of a pair of cover halves 17 and 18 having a semicircular cross-sectional shape. The first cover 15 is connected to the outer periphery of the exhaust pipe 13. A cylindrical cover that covers the entire circumference of the exhaust pipe 13 so as to form an annular gap 21 therebetween and is welded to the outer circumference of the exhaust pipe 13 at one or a plurality of locations along the longitudinal direction of the exhaust pipe 13. The main portion 22 is connected to one end portion in the axial direction of the cover main portion 22 (in this embodiment, the downstream end portion along the exhaust flow direction 24 in the exhaust pipe 13) and is in sliding contact with the outer periphery of the exhaust pipe 13. In addition, the exhaust pipe 13 is configured to have a reduced diameter cylindrical portion 23 slidably fitted in the second cover 16 adjacent in the longitudinal direction of the exhaust pipe 13.

  Referring also to FIG. 5, the exhaust ends of the pair of cover halves 17, 18 constituting the first cover 15 are welded to the outer periphery of the exhaust pipe 13 at the same time. The welded portions 25 and 26 are formed at the same place in the longitudinal direction of the pipe 13, respectively. In this embodiment, near the upstream end of the first cover 15 along the exhaust flow direction 24. The welded parts that are recessed inward along the radial direction of the exhaust pipe 13 so as to be arranged at the same location in the longitudinal direction of the exhaust pipe 13 at both ends in the circumferential direction of the cover halves 17 and 18 25 and 26 are formed. The welded portions 25 and 26 are welded to the outer periphery of the exhaust pipe 13 so that the first cover 15 is joined to the exhaust pipe 13 and the pair of cover halves 17 and 18 are formed. The first cover 15 is configured by being joined to each other.

  On the other hand, the second cover 16 includes a pair of cover halves 19 and 20 having a semicircular cross-sectional shape, covers the entire circumference of the exhaust pipe 13 and extends in the longitudinal direction of the exhaust pipe 13. A second cover that is configured in a cylindrical shape so as to be welded to the outer periphery of the exhaust pipe 13 at a plurality of locations, for example, at three locations, and has the same outer diameter over the maximum outer diameter of the second cover 16, that is, the entire axial length. The outer diameter D2 of 16 is set to be the same as the outer diameter D1 of the cover main portion 22 in the first cover 15.

  A pair of the cover halves 19 and 20 constituting the second cover 16 is disposed at one end in the circumferential direction of the second cover 16 in the longitudinal direction of the exhaust pipe 13 so as to be disposed at an intermediate portion in the axial direction of the second cover 16. A welded portion 27 that is disposed at the same location and is recessed inward in the radial direction of the exhaust pipe 13 is formed, and the exhaust circulation is provided at the other circumferential end of the pair of cover halves 19 and 20. The second cover 16 is disposed near the upstream end and the downstream end of the second cover 16 along the direction 24 and is disposed at the same position in the longitudinal direction of the exhaust pipe 13 and on the inner side along the radial direction of the exhaust pipe 13. Recessed welded portions 28 and 29 are formed. The welded portions 27 to 29 are welded to the outer periphery of the exhaust pipe 13 so that the second cover 16 is joined to the exhaust pipe 13 and the pair of cover halves 19 and 20 are formed. The second cover 16 is constituted by being joined to each other.

  The reduced diameter cylindrical portion 23 of the first cover 15 is a first sliding cover cylindrical portion 23a that is in sliding contact with the outer periphery of the exhaust pipe 13, and a first cover 16 having the same outer diameter D2 over the entire length. A cylindrical fitting cylindrical portion 23b slidably fitted to an end portion on the cover 15 side, a first tapered portion 23c connecting the sliding contact cylindrical portion 23a and the fitting cylindrical portion 23b, and the fitting It consists of a combined cylindrical portion 23b and a second tapered portion 23d connecting the cover main portion 22.

  Next, the operation of this embodiment will be described. The first and second covers 15 and 16 are composed of a pair of cover halves 17, 18: 19 and 20 having a semicircular cross-sectional shape, and an exhaust pipe. The first cover 15 of the first and second covers 15 and 16 adjacent to each other in the longitudinal direction of the exhaust pipe 13 forms an annular gap 21 between the first cover 15 and the outer periphery of the exhaust pipe 13. A cylindrical cover main part 22 that covers the entire circumference and is welded to the exhaust pipe 13 at one location along the longitudinal direction of the exhaust pipe 13, and is connected to one end of the cover main part 22 in the axial direction. The first and second covers 15 and 16 have a reduced diameter cylindrical portion 23 that is slidably contacted with the outer periphery of the exhaust pipe 13 and slidably fitted into the second cover 16. Adsorbs heat elongation reliably and is adjacent to each other In addition to suppressing the generation of abnormal noise due to vibration at the overlapping portion of the first and second covers 15 and 16, the stress applied to the welded portion is reduced by reducing the load on the welded portion by suppressing the radial spread. Can increase the sex.

  Of the first and second covers 15 and 16 adjacent in the longitudinal direction of the exhaust pipe 13, the outer diameter D1 of the cover main portion 22 of the first cover 15 and the maximum outer diameter of the second cover 16. Since D2 is the same, the spread in the radial direction can be suppressed, and the first and second covers 15 and 16 can be downsized in the radial direction.

  Further, the exhaust pipe 13 and the cover halves 17, 18; 19, 20 constituting the first and second covers 15, 16 are welded simultaneously to the outer periphery of the exhaust pipe 13 at the circumferential ends thereof. Since the welded parts 25, 26; 27, 28, 29 arranged at the same place in the longitudinal direction of the pipe 13 are formed, it is possible to perform the positioning of the welded part with high accuracy in one step, and the manufacture is easy. Become.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. Is possible.

13 ... Exhaust pipes 15, 16 ... Covers 17, 18, 19, 20 ... Cover half 21 ... Ring gap 22 ... Cover main part 23 ... Reduced diameter cylindrical parts 25, 26 , 27, 28, 29 ... welded part D1 ... outer diameter D2 of cover main part ... maximum outer diameter of the other cover

Claims (3)

  A plurality of covers (15, 16) arranged along the longitudinal direction of the exhaust pipe (13) cover the exhaust pipe (13) so as to cover at least a part along the circumferential direction of the exhaust pipe (13). In the exhaust pipe cover structure to be joined, the cover (15, 16) includes a pair of cover halves (17, 18; 19, 20) having a semicircular cross-sectional shape, and the exhaust pipe (13 ) In the longitudinal direction of the exhaust pipe (13) so that one of the covers (15, 16) (15) forms an annular gap (21) with the outer periphery of the exhaust pipe (13). ) And a cylindrical cover main part (22) welded to the exhaust pipe (13) at a plurality of places or one place along the longitudinal direction of the exhaust pipe (13), and the cover main part ( 22) connected to one axial end of the exhaust pipe (13) An exhaust having a reduced diameter cylindrical portion (23) that is slidably contacted with the outer periphery and is slidably fitted into the other (16) of the pair of covers (15, 16). Tube cover structure.   The outer diameter (D1) of the cover main portion (22) of one (15) of the pair of covers (15, 16) adjacent in the longitudinal direction of the exhaust pipe (13) and the maximum of the other cover (16) The exhaust pipe cover structure according to claim 1, wherein the outer diameter (D2) is set to be the same.   The exhaust pipe is welded to the outer periphery of the exhaust pipe (13) at the circumferential ends of the pair of cover halves (17, 18; 19, 20) constituting the cover (15, 16). 3. The exhaust pipe cover structure according to claim 1, wherein welded portions (25, 26, 27, 28, 29) arranged at the same location in the longitudinal direction of the pipe (13) are formed. .

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