JP4721458B2 - Heat shield plate mounting structure by welding - Google Patents

Description

  The present invention relates to a heat shield plate mounting structure by welding to a heat radiation component such as a catalytic converter.

Conventionally, as a structure for attaching a heat shield plate to a catalytic converter or exhaust conduit for exhaust gas purification treatment in an internal combustion engine or the like, a belt-like bracket is attached to the peripheral flange of the catalytic converter by caulking, and the belt-like bracket is shielded via a screw. A heat plate is attached (conventional example 1), the opening edge of the heat shield covering the outer periphery of the catalytic converter is aligned with the shape of the main body of the catalytic converter, and welding is performed along the opening edge. What is attached by doing so is known (conventional example 2) (for example, refer to Patent Document 1).
JP 2002-285835 A

  However, the mounting structure of the heat shield plate of the conventional example 1 requires two steps of mounting the bracket and the heat shield plate, so that there is a problem that the number of parts is large and the mounting work is complicated.

  Further, the heat shield plate mounting structure by welding in Conventional Example 2 has the following problems.

  That is, when arc welding is used to fix the catalytic converter body and the heat shield plate, the start and end of current flow tend to be relatively high, and the welding start and end portions of the heat shield plate are Due to the high temperature, there is a problem that the heat shield plate as a base material in the vicinity of the start end portion and the end end portion is easily melted and durability is lowered.

  Therefore, it is necessary to take measures such as increasing the thickness of the heat shield plate, which increases the weight and material cost.

  The problem to be solved by the present invention is that the heat shielding plate and the heat radiation component can be satisfactorily welded without causing an increase in weight and material cost, and heat shielding by welding that can realize high product quality and improved durability. It is to provide a plate mounting structure.

  In order to solve the above-described problem, the heat shield plate mounting structure according to claim 1 is a heat shield plate of a heat radiation component in an exhaust system of an internal combustion engine, and a middle portion of the mounting edge of the heat shield plate has a predetermined length. In this structure, the heat shield plate is fixed to the heat radiation component by welding, and a notch portion is formed in advance at a start end portion or a terminal end portion of the weld portion.

  In the heat shield plate mounting structure according to the present invention, as described above, a notch is formed in advance at the start end or end of the welded portion, so that the vicinity of the start end or end of the weld is formed. It is possible to prevent the heat shield plate from being melted, thereby eliminating the cracks generated from the melted portion.

  Therefore, it is possible to satisfactorily weld the heat shield plate and the heat radiation component without increasing the weight and material cost, thereby realizing high product quality and improved durability.

  Embodiments of the present invention will be described below with reference to the drawings.

  The mounting structure of the heat shield plate by welding according to this embodiment corresponds to the invention described in claims 1 to 3. In this embodiment, a case where a heat shield is attached to the outer periphery of the catalytic converter (heat radiation component) will be described as an example.

  First, a heat shield plate mounting structure by welding according to this embodiment will be described with reference to the drawings.

  FIG. 1 is an overall view showing a heat shield plate mounting structure by welding according to this embodiment, FIG. 2 is a detailed view of a portion A1 in FIG. 1, FIG. 3 is a longitudinal sectional view taken along the line BB in FIG. It is a vertical end view in CC line of 1.

  As shown in FIG. 1, the heat shield plate mounting structure by welding includes a catalytic converter (heat radiation component) 1 and a heat shield plate 2.

  More specifically, the catalytic converter 1 includes a catalyst carrier 11 in which a catalyst carrier S for purifying exhaust gas from an engine is accommodated, and connection flanges 12 and 12 provided at both ends of the catalyst carrier 11. Yes.

  At both ends of the catalyst carrier portion 11, tapered taper cylinder portions 11a and 11a are provided, and at the tips thereof, small-diameter pipes 11b and 11b are provided. It is connected.

  The heat shield plate 2 serves to block the heat radiated from the catalyst carrier 11 of the catalytic converter 1, and the catalyst carrier 11 of the catalytic converter 1, the tapered tapered cylinders 11a and 11a, and the small diameter pipe. A large-diameter cylindrical portion 21 that covers the outer periphery of 11b and 11b by forming a predetermined space O1, tapered taper cylindrical portions 22 and 22 connected to both ends of the large-diameter cylindrical portion 21, and tapered tapered cylindrical portions 22 and 22; It is comprised by the small diameter cylinder parts 23 and 23 connected to both ends.

  Then, as shown in FIG. 3, the heat shield plate 2 is divided into upper and lower parts, and by connecting the ear parts 24, 24 provided on both side edges of both divided bodies 2a, 2b by spot welding or the like. It is integrated into a cylindrical tube with a different diameter.

  Returning to FIG. 1, the heat shield plate 2 is attached to the catalytic converter 1 by the small diameter cylindrical portion 23 in one of the divided bodies 2 a and 2 b of the heat shield plate 2 (the upper divided body 2 a in this embodiment), This is carried out by welding a part of the middle portion of the front end edge portion (attachment edge portion of the heat shield plate) 23 to the outer peripheral surfaces of the small-diameter pipes 11b and 11b in the catalytic converter 1 over a predetermined length.

  More specifically, as shown in FIGS. 2 to 4, the welded portion 25 a where the welding E is performed at the distal end edges of the small diameter cylindrical portions 23, 23 is along the outer circumferential arc surface of the small diameter pipes 11 b, 11 b of the catalytic converter 1. By forming the recessed portions 25 and 25 that are recessed so as to come into contact with each other, a predetermined gap h is provided between the other circumferential portions and the outer peripheral surfaces of the small-diameter pipes 11b and 11b in the catalytic converter 1. The predetermined space O1 is formed.

  Moreover, the step part between the hollow part 25 used as the high temperature heat receiving part by the welding E in the said heat-shielding board 2, and the hollow part 25 used as the terminal part E2, and the other non hollow part (non-welded part) 26 Arc-shaped notches 27 and 27 are formed in advance in 25b and 25b.

  Next, the operation of this embodiment will be described.

  When attaching the heat shield plate 2 configured in this way to the catalytic converter 1, first, both ears with the split bodies 2 a and 2 b of the heat shield plate 2 divided into two parts in the upper and lower directions sandwiched from the upper and lower sides of the catalytic converter 1. The parts 24 and 24 are connected to each other by spot welding or the like so as to cover the outer periphery of the catalytic converter 1.

  Next, the welded portions 25a and 25a in the upper split pair 2a are welded E along the outer circumferential arc surfaces of the small-diameter pipes 11b and 11b of the catalytic converter 1, respectively, so that the catalytic converter 1 and the heat shield plate 2 are interposed. The heat shield plate 2 can be attached and fixed in a state where a predetermined gap is formed.

  In addition, when the vehicle is mounted, the catalytic converter 1 to which the heat shield plate 2 is attached is fastened to the connection pipe on the engine side (exhaust manifold assembly portion) (not shown) on one side of the connection flanges 12 and 12. On the other hand, a connecting pipe on the main muffler side (not shown) is fastened to the other side.

  Then, harmful components contained in the exhaust gas flowing in from the engine side of the catalytic converter 1 are purified into harmless components when passing through the catalyst carrier S and then discharged to the main muffler side.

  At this time, the purification performance of the catalyst carrier S is accelerated under a high temperature condition, and the heat shield plate 2 covers the catalytic converter 1 to prevent the temperature of the exhaust gas from being lowered, thereby purifying the catalyst carrier S. It plays the role of improving performance and the role of preventing heat damage due to heat dissipation of the catalytic converter 1, and functions as a heat shield.

  In addition, the above-described effects can be further improved by the heat insulating space O1 formed by the gap h between the heat shield plate 2 and the catalytic converter 1.

  Next, the effect of this embodiment will be described.

  In the mounting structure of the heat shield plate by welding of this embodiment, as described above, the recessed portion 25 serving as the start end portion E1 and the end end portion E2 of the two welded portions 25a, 25a and the other non-recessed portion (non-welded portion) 26. The cutout portions 27 and 27 are formed in advance in the step portions 25b and 25b between the heat shield plate 2 and the heat shield plate 2 in the vicinity of the start end E1 and the end end E2 can be prevented from fusing. Thus, there is no risk of cracks occurring from the melted part.

  Therefore, the heat shield plate 2 and the catalytic converter 1 can be well welded without causing an increase in weight and material cost, and high product quality and durability can be improved.

  Conventionally, since the welding work is difficult in the vicinity of the connection flange 12, there is a limit in bringing the end edge portion of the heat shield plate 2 close to the connection flange 12.

  That is, there is a problem that the heat shield range of the catalytic converter 1 by the heat shield plate 2 is narrowed by the amount of the weld bead (weld E) protruding from the end edge.

  On the other hand, in this embodiment, as described above, the welded portion 25a where the welding E is performed at the front end edges of the small-diameter cylindrical portions 23, 23 is along the outer circumferential arc surface of the small-diameter pipes 11b, 11b of the catalytic converter 1. In this way, when the depression 25 is formed, the line L1 of the welded portion 25a is a non-welded portion in a plan view when the depression 25 is formed. Therefore, the non-recessed portion 26 that is a non-welded portion can be attached in a state of being close to the connection flange 12.

  Therefore, the effect that the heat shield range of the catalytic converter 1 by the heat shield plate 2 can be increased can be obtained.

  Although the present embodiment has been described above, the present invention is not limited to the above-described embodiment, and design changes and the like within a scope not departing from the gist of the present invention are included in the present invention.

  For example, in the embodiment, the catalytic converter is described as an example of the heat radiating component. However, the present invention can be applied to other heat radiating components such as an exhaust manifold.

  The size, shape, etc. of the notch can be set as appropriate.

  Moreover, although the example which formed the notch part beforehand in the both ends of the welding end part and the terminal part was shown in the Example, a notch part may be formed only in either one of a starting end part or a terminal part.

  Further, in the embodiment, the recess 25a is recessed so that the welded portion 25a where the welding E is performed at the front end edge of the small diameter cylindrical portion 23, 23 is in contact with the outer peripheral arc surface of the small diameter pipe 11b, 11b of the catalytic converter 1. Although the portions 25 are formed, they may be directly overlapped.

It is a general view which shows the attachment structure of the heat shield by the welding of this Example. FIG. 2 is a detailed view of part A1 in FIG. It is a longitudinal cross-sectional view in the BB line of FIG. It is a vertical end view in the CC line of FIG.

Explanation of symbols

1 Catalytic converter (thermal radiation component)
DESCRIPTION OF SYMBOLS 11 Catalyst support part 11a Tapered taper part 11b Small diameter pipe part 12 Connection flange 2 Heat shield plate 2a Upper part 2b Lower part 21 Large diameter cylinder part 22 Tapered taper part 23 Small diameter cylinder part 24 Ear part 25 Depression part 25a Welding part 25b Stepped portion 26 Non-recessed portion (non-welded portion)
27 Notch E Welding
E1 start end E2 end h clearance O1 heat insulation space S catalyst carrier X1 welding

Claims (3)

A heat shield plate mounting structure for fixing a heat shield plate of a heat radiation component in an exhaust system of an internal combustion engine to a heat radiation component by welding a middle portion of an attachment edge of the heat shield plate over a predetermined length,
A heat shield plate mounting structure by welding, wherein a notch portion is formed in advance at a starting end portion or a terminal end portion of the welding portion. In the heat shield plate mounting structure by welding according to claim 1,
A heat insulating space is formed between the heat shield and the heat radiation component,
2. A heat shield plate mounting structure by welding, wherein a recessed portion is formed in a welded portion of the heat shield plate so as to be recessed toward the heat radiation component.   The heat shield plate mounting structure according to claim 2, wherein the notch is formed in a step portion between the recessed portion and the non-recessed portion.

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