JPH04276114A - Installation structure of catalytic converter - Google Patents

Abstract

PURPOSE:To facilitate assembly of a catalytic converter and effectively absorb oscillation of an engine by providing an elastic seal between a flange on the upstream side of a case and a flange on the engine side, and by providing an installation tool on the upstream side to join the flange on the upstream side of the case and the flange on the engine side. CONSTITUTION:At the time of installing a catalytic converter 6 in the middle of an exhaust pipe, an upstream part 14a of a catalyzer case 14 is held against a downstream part 2-2a of a second exhaust pipe 2-2 on the upstream part of the catalytic converter 6. Additionally, an elastic seal body 36 is fitted in the downstream part 2-2a of the second exhaust pipe 2-2. At this time, a seal spherical surface part 34 of the elastic seal body 36 is made contact with a flange spherical surface part 22 of a flange 18 on the upstream side of the catalyzer case 14, and the elastic seal body 36 is fitted in the downstream part 2-2a of the second exhaust pipe 2-2. An upstream side installation bolt 44 is inserted through an engine side bolt hole 4 from the engine side.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] This invention relates to a mounting structure for a catalytic converter, and in particular improves the ease of assembling it to an exhaust pipe, protects the catalytic converter from engine vibrations, etc., and prevents deterioration of the catalytic converter. The present invention relates to a mounting structure for a catalytic converter that can be easily confirmed.

0002

[Prior Art] In a vehicle engine, a catalytic converter is installed in the middle of the exhaust pipe in order to convert harmful exhaust from the engine into harmless exhaust by the action of a catalytic substance under predetermined gas composition and temperature conditions. ing. As shown in FIG. 5, the catalytic converter 102 includes a catalyst body 104 configured by holding a catalyst that reacts with exhaust gas on a carrier;
and a catalyst case 106 that holds the catalyst.

[0003] A case upstream flange 108 is fitted and fixed to the upstream portion 106a of the catalyst case 106. In the downstream part 110a of the engine side exhaust pipe 110,
An engine side flange 112 is fitted and fixed. The case upstream flange 108 and the engine side flange 112 are fastened together via an upstream gasket 114 with upstream mounting bolts 118 and upstream nuts 120, which are upstream fittings 116.

[0004] Also, the downstream part 106b of the catalyst case 106
A case downstream flange 122 is fitted and fixed to the case. In the upstream part 124a of the muffler side exhaust pipe 124,
A muffler side flange 126 is fitted and fixed. This case downstream flange 122 and muffler side flange 12
6 refers to the downstream mounting bolt 132 and downstream nut 1 that are the downstream mounting tool 130 via the downstream gasket 128.
It is concluded by 34.

Another mounting structure for a catalytic converter is shown in FIG. In FIG. 6, a downstream portion 208a of a connecting exhaust pipe 208 is inserted and welded to an upstream portion 206a of a catalyst case 206 in which a catalyst body 204 of a catalytic converter 202 is held. This communication exhaust pipe 208 is provided to secure a space for tightening an upstream mounting bolt 224, which will be described later, from the catalyst case 206 side. Upstream section 20 of this connecting exhaust pipe 208
A case upstream side flange 212 on which a flange spherical portion 210 is formed is fitted and welded to 8b. An engine-side flange 216 is fitted and welded to the downstream portion 214a of the engine-side exhaust pipe 214. An elastic seal body 220 in which a seal spherical portion 218 that matches the flange spherical portion 210 is formed is interposed at the downstream portion 214a of the engine side exhaust pipe 214 between the case upstream side flange 212 and the engine side flange 216. .

An upstream mounting bolt 224 of an upstream fitting 222 passes through the case upstream flange 212 and the engine side flange 216 from the catalyst case 206 side, and the case upstream flange 212 and the upstream mounting bolt 22
A spring 228 is interposed between the four heads 226. Further, the upstream mounting bolt 224 is provided with a retaining collar 230 that contacts the surface of the engine side flange 216 on the catalyst case 206 side. Engine side flange 216
An upstream nut 234 is screwed onto a threaded portion 232 of the upstream mounting bolt 224 that protrudes toward the engine from the upstream side. Furthermore, an upstream portion 236a of a muffler side exhaust pipe 236 is inserted into and welded to the downstream portion 206b of the catalyst case 206.

A mounting structure for such a catalytic converter is disclosed in, for example, Japanese Patent Laid-Open No. 56-56923. The design described in this publication utilizes a seamless, single-plate element to prevent bypass leakage and accommodate large increases in backpressure.

[0008]

[Problem to be solved by the invention] However, conventionally, FIG.
In the catalytic converter mounting structure shown in Figure 1, the case upstream flange at the upstream side of the catalyst case is connected in contact with the engine side flange at the downstream side of the engine side exhaust pipe that is directly connected to the engine. There was a drawback that vibrations from the side were largely transmitted to the catalytic converter side via the engine side flange and the case upstream side flange, resulting in damage to the catalyst body. In order to solve this problem, it is conceivable to interpose a flexible exhaust pipe in the middle of the engine side exhaust pipe to absorb vibrations, but this has disadvantages in terms of layout and cost.

In addition, in the catalytic converter mounting structure shown in FIG. 6, the upstream part of the catalyst case is welded to the connecting exhaust pipe, and the downstream part of the catalyst case is welded to the muffler side exhaust pipe, and the flange connection is performed. Therefore, there was an inconvenience in that it was not possible to remove the muffler side exhaust pipe and check the deterioration state of the catalyst body after installation. Additionally, if you only want to replace the catalyst body inside the catalyst case, you will also have to replace parts that do not need to be replaced, such as the connecting exhaust pipe, muffler side exhaust pipe, and upstream side flange, resulting in wasted parts. There was this inconvenience.

0010

[Means for Solving the Problems] Therefore, in order to eliminate the above-mentioned disadvantages, the present invention provides a mounting structure for a catalytic converter installed between an engine-side exhaust pipe and a muffler-side exhaust pipe. A downstream side flange of the case is provided at the downstream side of the case, and a muffler side flange is provided at the upstream side of the muffler side exhaust pipe to be joined to the case downstream side flange, and a downstream side flange is provided where the case downstream side flange and this muffler side flange are fastened. A downstream fitting consisting of a mounting bolt and a downstream nut is provided, and a case upstream flange in which a flange spherical part is formed is provided at the upstream part of the catalyst case, and a case upstream side flange is provided at the downstream part of the engine side exhaust pipe. An engine-side flange facing the flange is provided, and an elastic seal body having a seal spherical surface in contact with the flange spherical surface is provided between the case upstream-side flange and the engine-side flange, and the case upstream-side flange and the engine Provide an upstream mounting fixture consisting of an upstream mounting bolt and an upstream nut that fasten to the side flange,
A spring is interposed between the head of the upstream mounting bolt and the engine side flange, and the upstream nut is screwed into the upstream threaded portion of the upstream mounting bolt that passes through the case upstream flange. It is characterized by being provided together.

[0011]

[Operation] According to the configuration of the present invention, when installing the catalytic converter in the exhaust pipe, on the upstream side of the catalyst case,
The engine side flange provided at the downstream part of the engine side exhaust pipe is arranged to face the case upstream side flange provided at the upstream part of the catalyst case, and the engine side exhaust pipe is arranged between the case upstream side flange and the engine side flange. An elastic seal body is fitted into the pipe, and the flange spherical part of the case upstream flange is placed in contact with the seal spherical part of the elastic seal body, and a spring is installed between the engine side flange and the head of the upstream mounting bolt. is interposed, and an upstream nut is screwed onto the upstream threaded portion of the upstream mounting bolt that penetrates from the case upstream flange to the catalyst case side, thereby fastening the case upstream flange and the engine side flange. Therefore, since the upstream mounting bolt can be tightened from the engine side, the upstream mounting bolt does not interfere with the catalyst case, and ease of assembly can be improved.

On the other hand, on the downstream side of the catalyst case, the case downstream flange and the muffler side flange are opposed to each other,
Then, the downstream side flange of the case and the muffler side flange are fastened together using a downstream side fixture.

Next, when the engine is running, the vibrations transmitted from the engine side to the engine side exhaust pipe are absorbed by the elastic seal, and the catalyst case is elastically supported by the elastic seal and the spring. , damage to the catalyst body can be prevented and the function of the catalytic converter can be maintained well.

Furthermore, if you want to check the deterioration state of the catalyst body inside the catalyst case, you can remove the downstream side fitting and remove the muffler side exhaust pipe, and check the catalyst body inside the catalyst case from the downstream side of the catalyst case. The state of deterioration can be easily confirmed.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described in detail and specifically below with reference to the drawings. 1 to 4 show embodiments of this invention. In FIG. 2, 2 is an exhaust pipe whose one end is connected to an engine (not shown), 4 is a front catalytic converter, 6 is a rear catalytic converter, and 8 is a muffler. The exhaust pipe 2 is the first exhaust pipe between the engine and the front catalytic converter 4.
It consists of an exhaust pipe 2-1, a second exhaust pipe 2-2 between the front catalytic converter 4 and the rear catalytic converter 6, and a third exhaust pipe 2-3 between the rear catalytic converter 6 and the muffler 8. An engine mounting flange 10 attached to the engine is fixed to the first exhaust pipe 2-1.

The rear catalytic converter (hereinafter simply referred to as "catalytic converter") 6, as shown in FIG.
It consists of a catalyst case 14 that holds this catalyst body 12.

The upstream side of the catalytic converter 6 is connected to the second exhaust pipe 2-2 by an upstream flange joint 16. That is, the upstream fixing part 20 of the case upstream flange 18 is fitted and welded to the upstream part 14a of the catalyst case 14. This upstream fixing part 20 has a catalyst case 1
An upstream side flange spherical surface part 22 extending obliquely from the upstream surface 14c of the upstream part 14a of No. 4 is connected to the upstream side. This upstream flange spherical portion 22 has a catalyst case 14
An upstream side flange portion 24 is continuously provided which is substantially orthogonal to the axial direction of the upstream portion 14a.

Further, in the downstream part 2-2a of the second exhaust pipe 2-2, which is the engine-side exhaust pipe, there is an engine-side fixing part of the engine-side flange 26 at a distance L from the downstream surface 2-2c to the upstream side. 28 is fitted and welded. This engine side fixed part 28 includes a downstream part 2-2a of the second exhaust pipe 2-2.
An engine-side curved portion 30 that protrudes and curves toward the downstream surface 2-2c of the engine is connected to the engine-side curved portion 30. An engine side flange portion 32 is connected to the engine side curved portion 30 and is substantially perpendicular to the axial direction of the downstream portion 2-2a of the second exhaust pipe 2-2 and faces the upstream side flange portion 24. has been done.

The downstream portion 2-2a of the second exhaust pipe 2-2 has a width extending from the downstream surface 2-2c to the engine-side curved portion 30 and a predetermined thickness, and has the case upstream flange 18. A seal spherical part 34 that matches the flange spherical part 22 of
An annular elastic seal body 36 having a shape formed therein is fitted.

The upstream surface 14c of the upstream portion 14a of the catalyst case 14 and the downstream surface 2-2c of the downstream portion 2-2a of the second region pipe 2-2 are spaced apart from each other by a predetermined distance.

The upstream side flange 24 and the engine side flange 32 are provided with an upstream side bolt hole 38 and an engine side bolt hole in the same position in the axial direction of the downstream section 2-2a of the second exhaust pipe 2-2. A bolt hole 40 is formed.

The upstream side bolt hole 38 and the engine side bolt hole 40 are provided with an upstream side fitting 42 located approximately parallel to the axial direction of the downstream portion 2-2a of the second exhaust pipe 2-2. Mounting bolts 44 are inserted. This upstream mounting bolt 4
4 includes an upstream head 46 disposed closer to the engine than the engine side flange 32, an upstream shaft 48 connected to the upstream head 46, and an engine side flange of the upstream flange 24. A bolt retaining collar 50 protrudes from the tip side of the upstream shaft portion 48 so as to be in contact with the surface on the side of the portion 32 , and the upstream collar portion 24
and an upstream threaded portion 52 protruding toward the catalyst case 14 side.

A spring 5 is provided between the upstream head 46 and the engine side flange 32 and is compressed between the upstream head 46 and the engine side flange 32 and fitted into the upstream shaft 48.
6 is provided. Further, an upstream nut 58 is screwed onto the upstream sticky portion 52 from the catalyst case 14 side.

On the other hand, the downstream side of the catalytic converter 6 is connected to a third exhaust pipe, which is a muffler side exhaust pipe, by a downstream flange joint 60.
It is connected to the exhaust pipe 2-3. That is, a case downstream side flange 62 having a predetermined thickness and extending substantially orthogonal to the axial direction of the downstream portion 46b is protruded and fixed to the downstream portion 14b of the catalyst case 14. Further, the upstream portion 2-3a of the third exhaust pipe 2-3 has a muffler side flange having a predetermined thickness that is substantially perpendicular to the axial direction of the upstream portion 2-3a and facing the downstream side flange 62. 64 is fitted and fixed. This case downstream flange 62 and muffler side flange 64
A downstream gasket 66 is interposed between the two.

A downstream bolt hole 68 and a muffler bolt hole 70, which are oriented in the axial direction of the downstream portion 14b of the catalyst case 14, are formed in the case downstream side flange 62 and the muffler side flange 64.

A downstream bolt 74 of a downstream fitting 72 is inserted into the downstream bolt hole 68 and the muffler bolt hole 70. The downstream bolt 74 includes a downstream head 76 that contacts the surface of the downstream flange 62 on the catalyst case 14 side, and a downstream shaft portion 78 that is connected to the downstream head 76.
It consists of a downstream threaded portion 80 of the muffler side flange 64 that protrudes toward the muffler 8 side. A downstream nut 82 is screwed onto the downstream threaded portion 80 .

Next, the operation of this embodiment will be explained. When installing the catalytic converter 6 in the middle of the exhaust pipe 2, on the upstream side of the catalytic converter 6, the upstream part 14a of the catalyst case 14 is opposed to the downstream part 2-2a of the second exhaust pipe 2-2, and An elastic seal body 36 is fitted to the downstream portion 2-2a of the second exhaust pipe 2-2. At this time, the seal spherical part 34 of the elastic seal 36 is brought into contact with the flange spherical part 22 of the case upstream flange 18, and the elastic seal 36 is fitted into the downstream part 2-2a of the second exhaust pipe 2-2.

Then, a spring 56 is fitted to the upstream shaft portion 48 of the upstream mounting bolt 44, and the upstream mounting bolt 4
4 into the engine side bolt hole 40 from the engine side,
Then, the retaining collar 50 is brought into contact with the surface of the upstream collar 24 on the engine side collar 32 side, the upstream threaded section 52 is inserted into the upstream bolt hole 38, and the upstream threaded section 52 is fitted with an upstream nut. 58, and then tighten the upstream mounting bolt 44.
from the engine side and tighten the upstream part 14 of the catalyst case 14.
a and the downstream portion 2-2a of the second exhaust pipe 2-2.

On the other hand, on the downstream side of the catalytic converter 6, a case downstream flange 62 and a muffler side flange 64 are connected.
A downstream gasket 66 is interposed between the downstream mounting bolt 74 and the downstream mounting bolt 74 is inserted from the catalyst case 14 side into the downstream bolt hole 68 and the muffler bolt hole 70.
Attach the downstream nut 8 from the muffler 8 side to the downstream threaded portion 80 of 4.
Screw on 2.

When the engine is in operation, vibrations from the engine are transmitted to the second exhaust pipe 2-2, but since these vibrations are absorbed by the elastic seal 36, the catalyst body 12 In addition to being able to prevent damage, the elastic seal body 36 and the catalytic converter 6 are elastically supported by the second exhaust pipe 2-2 due to the presence of the spring 56, and the catalytic converter 6 can be protected.

Furthermore, if you wish to check the deterioration state of the catalyst body 12, remove the downstream fitting 72 and connect the third exhaust pipe 2-
3, the deterioration state of the catalyst case 14 can be easily checked, which is convenient.

As a result, since the upstream mounting bolts 44 can be tightened from the engine side, the catalyst case 14 does not get in the way as in the conventional case, improving the ease of assembling the catalytic converter 6, and improving engine operation. In some cases, vibrations from the engine side are effectively absorbed by the elastic sealing body 36, and the deterioration state of the catalyst body 12 can be easily checked simply by removing the third exhaust pipe 2-3.

[0033] Furthermore, the conventional elastic exhaust pipe that absorbs the vibrations that are transmitted to the catalyst body 12 is not required,
Since there is no need for a connecting exhaust pipe that forms a space for tightening the upstream mounting bolt 44, the number of parts and welding points can be reduced, and it is advantageous in terms of layout and cost. Can be done.

[0034]

[Effects of the Invention] As is clear from the above detailed description, according to the present invention, a case downstream flange is provided at the downstream part of the catalyst case, and a case downstream flange is connected to the upstream part of the muffler side exhaust pipe. A muffler side flange is provided, and a downstream side fitting consisting of a downstream side mounting bolt and a downstream side nut is provided for fastening the case downstream side flange and the muffler side flange. At the same time, an engine-side flange is provided at the downstream part of the engine-side exhaust pipe, facing the case upstream flange, and a seal spherical part that contacts the flange spherical part is formed between the case upstream flange and the engine-side flange. An upstream fitting consisting of an upstream mounting bolt and an upstream nut is provided to connect the upstream side flange of the case and the engine side flange. The installation of the catalytic converter is facilitated by inserting a spring and screwing an upstream nut into the upstream threaded portion of the upstream mounting bolt that passes through the upstream flange of the case. In addition to improving adhesion properties, the catalyst body can be protected by effectively absorbing vibrations from the engine side, and the deterioration state of the catalyst body can be easily checked.

Further, according to the configuration of the present invention, there is no need for a flexible exhaust pipe for absorbing engine vibrations or a connecting exhaust pipe for forming a space for tightening mounting bolts, and furthermore, The number of welded parts is also reduced, manufacturing is easy, and it can be advantageous in terms of layout and cost.

Furthermore, when replacing the catalyst body, it is not necessary to replace other parts all at once, and only the catalyst body can be replaced, thereby making it possible to prevent unnecessary use of parts.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a catalytic converter mounting structure.

FIG. 2 is a perspective view of an exhaust pipe with a catalytic converter attached.

FIG. 3 is a sectional view of the catalyst case.

FIG. 4 is a sectional view of the catalyst case.

FIG. 5 is a sectional view of a conventional catalytic converter mounting structure.

FIG. 6 is a sectional view of another conventional catalytic converter mounting structure.

[Explanation of symbols]

2 Exhaust pipe 4 Front catalytic converter 6 Rear catalytic converter 8 Muffler 12 Catalyst body 14 Catalyst case 16 Upstream flange joint 18 Case upstream flange 26 Engine side flange 30 Flange spherical part 34 Seal spherical part 36 Elastic seal body 42 Upstream side fitting 56 Spring 60 Downstream flange joint 62 Case downstream flange 64 Muffler side flange 72 Downstream side fitting

Claims (1)

[Claims] Claim 1: In a mounting structure for a catalytic converter installed between an engine-side exhaust pipe and a muffler-side exhaust pipe, a casing downstream flange is provided at a downstream part of the catalyst case, and a case downstream flange is provided at an upstream part of the muffler-side exhaust pipe. A muffler side flange is provided to be joined to the case downstream side flange, a downstream side fitting consisting of a downstream side mounting bolt and a downstream side nut is provided for fastening the case downstream side flange and this muffler side flange, and the flange spherical portion is provided. A formed case upstream flange is provided at the upstream part of the catalyst case, and an engine side flange facing the case upstream flange is provided at the downstream part of the engine side exhaust pipe, and the case upstream flange and the engine side An elastic seal body is provided between the flanges and has a seal spherical part that contacts the flange spherical part, and an upstream mounting bolt and an upstream nut connect the case upstream flange and the engine flange. A spring is interposed between the head of the upstream mounting bolt and the engine side flange, and the upstream threaded portion of the upstream mounting bolt penetrates through the case upstream flange. A catalytic converter mounting structure characterized by screwing together side nuts.