Patent Description:
A diesel or gas engine includes an engine body which is provided with a plurality of combustion chambers accommodating pistons, an exhaust gas pipe which guides an exhaust gas generated in the engine body to an external device such as a turbocharger, and a branch pipe. Each combustion chamber is connected to the exhaust gas pipe through the branch pipe. That is, the combined exhaust gas from each branch pipe flows through the exhaust gas pipe. The exhaust gas pipe has a tubular shape centered on the axis and the branch pipes are connected to intermediate positions in the axial direction.

Here, the temperature of the exhaust gas reaches about <NUM> while the engine is running. Due to the thermal stress of the exhaust gas, the exhaust gas pipe may be thermally deformed in the axial direction. In order to absorb such thermal deformation, for example, a technique described in <CIT> below is used. In <CIT> below, an elastic pipe that can be expanded and contracted in the axial direction is provided between a plurality of main exhaust pipes arranged in the axial direction. It is said that the influence of the thermal deformation can be avoided by expanding and contracting the elastic pipe according to the thermal deformation of the main exhaust pipe.

The main exhaust pipe and the elastic pipe described above are generally connected to each other by a flange as shown in <CIT> below. Specifically, the end portion of the main exhaust pipe is provided with a flange that spreads outward. The end portion of the elastic pipe is sandwiched between the flange and a ring-shaped member. The ring-shaped member and the flange are coupled by bolts and nuts. Further, such a connection portion is provided with a gasket to seal the leakage of the exhaust gas. The gasket is sandwiched between the ring-shaped member and the flange. <CIT> describes a flexible coupling device for use with a plurality of individual manifold sections that are sealably connected together and individually removable without disturbing the adjacent sections. <CIT> and <CIT> describe further exhaust manifold assemblies.

Here, it is necessary to replace the gasket periodically as the engine ages. At this time, the flange may be deformed due to thermal stress. Therefore, even if the bolt is tightened with a specified torque, there is a possibility that an appropriate surface pressure cannot be secured between the flange and the ring-shaped member. As a result, the sealing performance between the main exhaust pipe and the elastic pipe is degraded.

The present disclosure has been made to solve the above-described problems and an object thereof is to provide an exhaust gas pipe and an engine in which leakage of an exhaust gas is further reduced.

In order to solve the above-described problems, an exhaust gas pipe according to the present disclosure includes: a plurality of pipe bodies which are formed in a tubular shape centered on an axis and are arranged in a direction of the axis and through which an exhaust gas led from an engine body flows; a connection portion connecting a pair of the pipe bodies adjacent to each other in the direction of the axis; and a gasket which is provided between the pipe body and the connection portion, wherein a flange projecting toward an outer peripheral side is provided at an end portion of the pipe body in the direction of the axis, wherein the connection portion includes a main connection body which has a tubular shape centered on the axis and a pressing ring which is provided with a facing surface facing the flange while sandwiching the gasket in a gap between the flange and the facing surface, and wherein the exhaust gas pipe further includes: coupling members which are provided at intervals in a circumferential direction and coupling the flange and the pressing ring to each other; and a deformation prevention member that is provided in an outer peripheral region of the gap.

According to the present disclosure, it is possible to provide an exhaust gas pipe and an engine in which leakage of an exhaust gas is further reduced.

Hereinafter, an engine <NUM> and an exhaust gas pipe <NUM> according to a first embodiment of the present disclosure will be described with reference to <FIG>.

The engine <NUM> is, for example, a diesel engine or gas engine used as a power source for ships and power plants. The engine <NUM> includes an engine body <NUM>, an exhaust gas pipe <NUM>, and a branch pipe 2A. The engine body <NUM> is formed in a block shape and a plurality of (twelve as an example) combustion chambers <NUM> are formed therein. In this embodiment, six combustion chambers <NUM> are formed in two rows. Pistons (not shown) are accommodated in these combustion chambers <NUM>.

For example, in the case of a diesel engine, the fuel supplied to the combustion chamber <NUM> is compressed by the forward and backward movement of the piston, and the fuel spontaneously ignites. The output shaft of the engine <NUM> is rotated by such operations continuously occurring in each combustion chamber <NUM> with different timings. Rotational energy of the output shaft is extracted from the end of the shaft and used for various purposes (for example, driving a propeller in the case of a ship and driving a generator in the case of a power plant).

In each combustion chamber <NUM>, exhaust (exhaust gas) is generated as the fuel is burned. This exhaust is led to an external supercharger by the exhaust gas pipe <NUM>. More specifically, one end of the branch pipe 2A through which an exhaust gas flows is connected to each combustion chamber <NUM>. The other end of the branch pipe 2A is connected to the exhaust gas pipe <NUM>. That is, a total of twelve branch pipes 2A are connected to the exhaust gas pipe <NUM>. The exhaust gas pipe <NUM> extends along the direction in which the combustion chambers <NUM> are arranged.

Next, the configuration of the exhaust gas pipe <NUM> will be described with reference to <FIG>. As shown in <FIG> or <FIG>, the exhaust gas pipe <NUM> includes a plurality of pipe bodies <NUM>, a flange <NUM>, a connection portion <NUM>, a gasket G (see <FIG>), a coupling member <NUM>, and a deformation prevention member <NUM>.

As shown in <FIG>, the plurality of pipe bodies <NUM> are arranged at intervals in a direction of the axis Ac of the exhaust gas pipe <NUM>. The pipe body <NUM> has a tubular shape centered on the axis Ac. As an example, the outer diameter dimension of the pipe body <NUM> is about <NUM>. Further, as shown in <FIG>, the flange <NUM> is provided at the end portion of the pipe body <NUM> in the direction of the axis Ac. The flange <NUM> has an annular shape by projecting from the pipe body <NUM> toward the outer peripheral side. The flange <NUM> is coupled to the pipe body <NUM> by welding.

As shown in <FIG>, the connection portion <NUM> connects the pair of pipe bodies <NUM> adjacent to each other. The connection portion <NUM> includes a main connection body <NUM> and a pressing ring <NUM>. The main connection body <NUM> can be expanded and contracted in the direction of the axis Ac. Specifically, as shown in <FIG>, the main connection body <NUM> includes a collar 21A, a parallel portion 21B, and an elastic portion 21C. The collar 21A is a portion sandwiched between the flange <NUM> and the pressing ring <NUM> which will be described later.

The collar 21A has an annular plate shape centered on the axis Ac. The parallel portion 21B has a tubular shape extending in the direction of the axis Ac from the inner peripheral edge of the collar 21A. The elastic portion 21C is connected to the edge of the parallel portion 21B on the side opposite to the collar 21A. The elastic portion 21C has a curved shape that expands in diameter toward the outer peripheral side in a cross-sectional view. When a force is applied to the elastic portion 21C from the direction of the axis Ac, the elastic portion 21C bends and the entire main connection body <NUM> expands and contracts.

The pressing ring <NUM> has an annular plate shape centered on the axis Ac. The inner peripheral edge (ring inner peripheral edge 22T) of the pressing ring <NUM> is located on the inner radial side of the inner peripheral edge of the flange <NUM> in the radial direction. Further, the ring inner peripheral edge 22T contacts the parallel portion 21B. The pressing ring <NUM> faces the surface of the flange <NUM> on one side in the direction of the axis Ac (flange facing surface <NUM>) with a gap S therebetween.

The surface of the pressing ring <NUM> facing the other side in the direction of the axis Ac (the surface facing the flange <NUM>) is a facing surface <NUM>. That is, the gap S is surrounded by the flange facing surface <NUM> and the facing surface <NUM> from the direction of the axis Ac. The gasket G and the collar 21A are sandwiched in the gap S. Specifically, the gasket G is located on the other side in the direction of the axis Ac and the collar 21A is located on one side in the direction of the axis Ac in the gap S. The gasket G and the collar 21A are in close contact with each other. The gasket G has an annular plate shape centered on the axis Ac. For example, the gasket G is integrally made of SUS. Although not shown in detail, the gasket G is hollow and is configured to bend when pressed from both sides in the direction of the axis Ac.

An annular notch 22R which is recessed toward one side in the direction of the axis Ac and extends in the circumferential direction is formed in a region on the radial outside of a bolt (to be described later) of the facing surface <NUM> of the pressing ring <NUM>. The notch 22R is provided to hold the deformation prevention member <NUM> to be described later.

The coupling member <NUM> couples the flange <NUM> and the pressing ring <NUM> while sandwiching the gasket G and the collar 21Ain the gap S as described above. As shown in <FIG>, a plurality of (twelve as an example) the coupling members <NUM> are provided at intervals in the circumferential direction. The coupling member <NUM> includes a bolt and a nut. That is, a hole through which a bolt is inserted is formed in the flange <NUM> and the pressing ring <NUM>. The outer peripheral edge (collar edge 21t) of the collar 21A and the outer peripheral edge (gasket edge Gt) of the gasket G are located on the inner radial side of the bolt within the gap S. That is, an intermediate portion of the bolt is exposed in the gap S.

The deformation prevention member <NUM> is disposed in the gap S. The deformation prevention member <NUM> is provided to uniformly distribute the surface pressure in the radial direction between the flange <NUM> and the pressing ring <NUM>. As shown in <FIG>, the deformation prevention member <NUM> is inserted into the gap S from the outer peripheral side. Further, as shown in <FIG>, a plurality of (twelve as an example) the deformation prevention members <NUM> are provided at intervals in the circumferential direction. The circumferential position of the deformation prevention member <NUM> coincides with the circumferential position of the coupling member <NUM>. That is, one deformation prevention member <NUM> is provided on the outer peripheral side of one coupling member <NUM>. As shown in <FIG>, the deformation prevention member <NUM> includes a base portion <NUM> which is located on the outer peripheral side and a tapered portion <NUM> which extends from the base portion <NUM> toward the inner peripheral side.

The base portion <NUM> has a plate shape with an arcuate cross-sectional shape when viewed from the direction of the axis Ac. A through-hole h which extends in the circumferential direction is formed in the base portion <NUM>. A wire W is inserted through the through-hole h. As shown in <FIG>, the wire W is provided to hold the plurality of deformation prevention members <NUM> to prevent the detachment thereof. Again, as shown in <FIG>, the tapered portion <NUM> is provided integrally with the inner radial end surface of the base portion <NUM>, and the dimension in the direction of the axis Ac gradually decreases toward the inner radial side. That is, the tapered portion <NUM> has a triangular cross-sectional shape in a cross-sectional view including the axis Ac. The surfaces facing both sides of the tapered portion <NUM> in the direction of the axis Ac are tapered surfaces <NUM>. In a state in which the deformation prevention member <NUM> is inserted into the gap S, one tapered surface <NUM> comes into contact with the outer peripheral edge of the notch 22R and the other tapered surface <NUM> comes into contact with the outer peripheral edge of the flange facing surface <NUM>.

Next, the method of assembling the exhaust gas pipe <NUM> according to this embodiment and the behavior of the exhaust gas pipe <NUM> during the operation of the engine <NUM> will be described.

When assembling the exhaust gas pipe <NUM>, first, the plurality of pipe bodies <NUM> are connected by the connection portion <NUM>. Specifically, the gasket G and the collar 21A of the main connection body <NUM> are sandwiched between the flange <NUM> and the pressing ring <NUM>. In this state, the flange <NUM> and the pressing ring <NUM> are fastened by bolts and nuts as the coupling members <NUM>. The tightening torque of the bolt at this time is a predetermined specified value. In addition, when the bolt is tightened beyond this specified value, the flange <NUM> may be deformed to fall toward one side in the direction of the axis Ac with the joint (welded portion) with the pipe body <NUM> as a fulcrum. In other words, the specified value is appropriately determined within a range in which such deformation does not occur.

Next, the deformation prevention member <NUM> is inserted into the gap S from the outer peripheral side in the above-described state. Specifically, first, the plurality of deformation prevention members <NUM> through which the wires W are inserted are respectively arranged on the outer peripheral side of the gap S. Further, a striking force is applied to the base portion <NUM> of the deformation prevention member <NUM> with a hammer or the like so that the base portion is press-fitted into the gap S. Accordingly, the tapered surface <NUM> of the deformation prevention member <NUM> is in close contact with the flange <NUM> and the pressing ring <NUM> and cannot be removed. Finally, the wire W is tightened. Accordingly, the assembly of the exhaust gas pipe <NUM> is completed.

Next, the behavior of the exhaust gas pipe <NUM> during the operation of the engine <NUM> will be described. During the operation of the engine <NUM>, an exhaust gas of about <NUM> is generated in the combustion chamber <NUM>. This exhaust gas is sent to the exhaust gas pipe <NUM> through the branch pipe 2A. Due to the heat of the exhaust gas, the exhaust gas pipe <NUM> is thermally deformed in the direction of the axis Ac. This thermal deformation is absorbed by the elastic portion 21C of the connection portion <NUM> bending in the direction of the axis Ac as described above. Accordingly, the relative position of the exhaust gas pipe <NUM> and the branch pipe 2A is maintained and the engine <NUM> can continue to operate stably.

Here, when the sealing performance of the gasket G deteriorates with use over time, it is necessary to remove the bolt and nut as the coupling member <NUM>, replace the gasket G, and fasten the bolt and nut again. At this time, the flange <NUM> itself may also be thermally deformed by the heat of the exhaust gas. Specifically, in some cases, the flange <NUM> is deformed to fall in the direction of the axis Ac with the joint of the flange <NUM> and the pipe body <NUM> as a fulcrum. That is, the dimension in the direction of the axis Ac in the outer peripheral region of the gap S may be smaller than the initial size. In this case, even if the bolt and nut are tightened with a specified torque, the tightening force is not sufficiently transmitted between the flange <NUM> and the pressing ring <NUM>, and there is a possibility that the surface pressure against the gasket G cannot be secured.

Here, in this embodiment, the deformation prevention member <NUM> is provided in the gap S as described above. Specifically, the deformation prevention member <NUM> is provided in the outer peripheral region of the gap S formed between the flange <NUM> and the pressing ring <NUM>. Since the deformation prevention member <NUM> is disposed in the gap S, the flange <NUM> and the pressing ring <NUM> are mechanically coupled in the outer peripheral region of the gap S. That is, when the flange <NUM> and the pressing ring <NUM> are tightened by the coupling member <NUM>, a tightening force is transmitted between the flange <NUM> and the pressing ring <NUM> through the deformation prevention member <NUM>. Thus, even when the flange <NUM> is deformed and inclined in the direction of the axis Ac, it is possible to secure the surface pressure against the gasket G between the flange <NUM> and the pressing ring <NUM> by correcting the deformation of the flange <NUM>.

Further, in this embodiment, the deformation prevention member <NUM> includes the tapered portion <NUM> of which the dimension in the direction of the axis Ac gradually decreases from the outer radial side to the inner radial side. According to the above-described configuration, the deformation prevention member <NUM> can be disposed in the gap S of various sizes by adjusting the insertion amount of the tapered portion <NUM> with respect to the gap S according to the dimension of the gap S between the flange <NUM> and the pressing ring <NUM> in the direction of the axis Ac. Particularly, the thermal deformation of the flange <NUM> often occurs non-uniformly in the circumferential direction. According to the above-described configuration, even if such non-uniform thermal deformation occurs, the surface pressure of the gasket G can be uniformly secured by changing the insertion amount of the tapered portion <NUM>.

Additionally, in this embodiment, the notch 22R which is recessed in the direction of the axis Ac and extends in the circumferential direction is formed in the outer radial region of the facing surface <NUM>. According to the above-described configuration, since the notch 22R is formed in the pressing ring <NUM>, it is possible to more smoothly insert the deformation prevention member <NUM>. Further, since the insertion amount of the deformation prevention member <NUM> can be increased compared to the case in which the notch 22R is not formed, it is also possible to reduce the possibility of the detachment of the deformation prevention member <NUM>.

Furthermore, in this embodiment, the plurality of deformation prevention members <NUM> are provided at intervals in the circumferential direction. The wires W are inserted through the plurality of deformation prevention members <NUM>. According to the above-described configuration, since the plurality of deformation prevention members <NUM> are provided at intervals in the circumferential direction, the distribution of the surface pressure of the gasket G in the circumferential direction can be made uniform. Further, since the plurality of deformation prevention members <NUM> are connected by the wire W, it is possible to suppress the detachment of the deformation prevention member <NUM>. In addition, since the deformation prevention members <NUM> are also thermally connected to each other through the wire W, the distribution of the amount of heat input from the exhaust gas in the circumferential direction is smoothed. Accordingly, the amount of thermal expansion occurring in the pipe body <NUM> can be made uniform in the circumferential direction.

Further, in this embodiment, the deformation prevention member <NUM> is provided at a position that coincides with each coupling member <NUM> in the circumferential direction. According to the above-described configuration, since the deformation prevention member <NUM> is provided at a position in which the tightening force of the coupling member <NUM> is concentrated, the deformation prevention member <NUM> can disperse the tightening force in the circumferential direction and the radial direction. Accordingly, it is possible to further reduce the possibility of the deformation of the flange <NUM>.

The first embodiment of the present disclosure has been described above. Additionally, various changes and modifications can be made to each of the above configurations without departing from the gist of the present disclosure.

For example, it is possible to adopt the configuration shown in <FIG> as a modified example. In the example shown in the same drawing, the outer peripheral edge (gasket edge Gt') of the gasket G extends to the same position as the outer peripheral edge of the flange <NUM> in the radial direction. Further, the outer peripheral edge (collar edge 21t') of the collar 21A also extends to the same position as the outer peripheral edge of the flange <NUM> in the radial direction. That is, the gasket G and the collar 21A cover the entire surface of the flange facing surface <NUM>. Accordingly, the portion of the gasket G on the outer peripheral side of the coupling member <NUM> and the portion of the collar 21A on the outer peripheral side of the coupling member <NUM> constitute a deformation prevention member 40b.

According to the above-described configuration, the gasket G covers the entire surface of the flange <NUM>. Further, the outer radial portion (outer peripheral portion) of the gasket G functions as the deformation prevention member <NUM>. Accordingly, it is possible to secure the surface pressure against the gasket G as in the first embodiment. Further, according to the above-described configuration, since part of the gasket G and the collar 21A constitutes the deformation prevention member 40b, the number of parts is reduced and the cost required for manufacturing and maintaining the exhaust gas pipe <NUM> can be reduced.

Further, as a further modified example, it is also possible to adopt the configuration shown in <FIG>. In the example of the same drawing, the gasket edge Gt is located on the inner peripheral edge of the coupling member <NUM>. The collar edge 21t' is also located on the inner peripheral edge of the coupling member <NUM>. Even with such a configuration, it is possible to obtain the same effects as those of the modified example according to <FIG>. Additionally, in the example of <FIG>, the collar edge 21t' is folded back in the radial direction. In addition, since it is not necessary to form a hole through which a bolt as the coupling member <NUM> is inserted in the gasket G, it is possible to further reduce the possibility of leakage of the exhaust gas through the hole.

Next, a second embodiment of the present disclosure will be described with reference to <FIG>. In addition, the same configurations as those of the first embodiment and the modified example thereof are denoted by the same reference numerals and detailed description is omitted.

In this embodiment, a pipe P is provided around a bolt as the coupling member <NUM> to cover the bolt from the outer peripheral side. That is, the diameter of the insertion hole of the bolt formed in the flange <NUM> and the pressing ring <NUM> is larger than that of the first embodiment. Further, the pipe P extends in the direction of the axis Ac by the sum of the thicknesses of the flange <NUM>, the gasket G, the collar 21A, and the pressing ring <NUM>. Additionally, this sum is a value determined in advance at the time of design and is a value when the above-described thermal deformation does not occur in the flange <NUM>. The pipe P constitutes a deformation prevention member 40c.

According to the above-described configuration, when the bolt is tightened, the tightening amount of the bolt is limited by the pipe P as a deformation prevention member 40c. Specifically, the pipe P extends by the sum of the thicknesses of the flange <NUM>, the gasket G, the collar 21A, and the pressing ring <NUM>. The rigidity of the pipe P in the direction of the axis Ac prevents the bolt from being tightened beyond the total thickness. Thus, excessive bolt tightening is avoided, and deformation of the flange <NUM> can be prevented. As a result, it is possible to secure the surface pressure against the gasket G.

As described above, each embodiment of the present disclosure has been described. Additionally, various changes and modifications can be made to each of the above configurations without departing from the gist of the present disclosure. For example, in the above-described embodiments, the configuration of the exhaust gas pipe <NUM> has been described with the marine engine <NUM> taken as an example. However, the application of the exhaust gas pipe <NUM> is not limited to marine engine, and the exhaust gas pipe <NUM> can also be applied to other engines such as transportation machinery and power generation equipment.

Further, in the above-described embodiments, an example in which twelve bolts and nuts as the coupling members <NUM> are arranged in the circumferential direction has been described. However, the number of bolts and nuts is not limited to twelve, and can be changed as appropriate according to design and specifications.

Further, in the above-described embodiments, the example in which the gasket G is made of SUS has been described. However, the material of the gasket G is not limited to SUS, and the gasket G can be also made of heat-resistant resin or ceramics.

Further, the deformation prevention members <NUM>, 40b, and 40c described in each of the above-described embodiments and their modified examples can be applied in combination thereof.

The exhaust gas pipe <NUM> and the engine <NUM> described in each embodiment is understood, for example, as below.

According to the above-described configuration, the deformation prevention member <NUM> is provided in the outer peripheral region of the gap S formed between the flange <NUM> and the pressing ring <NUM>. Accordingly, for example, even when the flange <NUM> is deformed and inclined in the direction of the axis Ac, it is possible to secure the surface pressure against the gasket G between the flange <NUM> and the pressing ring <NUM> by sandwiching the deformation prevention member <NUM>.

(<NUM>) In the exhaust gas pipe <NUM> according to a second aspect, the deformation prevention member <NUM> may include the tapered portion <NUM> of which a length along the axis Ac gradually decreases from the outer radial side to the inner radial side.

According to the above-described configuration, the deformation prevention member <NUM> can be disposed in the gap S of various sizes by adjusting the insertion amount of the tapered portion <NUM> with respect to the gap S according to the length of the gap S between the flange <NUM> and the pressing ring <NUM> along the axis Ac.

(<NUM>) In the exhaust gas pipe <NUM> according to a third aspect, the notch 22R which is recessed in the direction of the axis Ac and extends in the circumferential direction may be formed on the outer radial region of the facing surface <NUM>.

According to the above-described configuration, since the notch 22R is formed in the pressing ring <NUM>, it is possible to more smoothly insert the deformation prevention member <NUM>.

(<NUM>) In the exhaust gas pipe <NUM> according to a fourth aspect, the plurality of deformation prevention members <NUM> may be provided at intervals in the circumferential direction and the exhaust gas pipe may further include the wire W connecting the plurality of deformation prevention members <NUM>.

According to the above-described configuration, since the plurality of deformation prevention members <NUM> are provided at intervals in the circumferential direction, the distribution of the surface pressure in the circumferential direction can be made uniform. Further, since the plurality of deformation prevention members <NUM> are connected by the wire W, it is possible to suppress the detachment of the deformation prevention member <NUM>. Further, since the deformation prevention members <NUM> are also thermally connected to each other through the wire W, the distribution of the amount of heat input from the exhaust gas in the circumferential direction is smoothed. Accordingly, the amount of thermal expansion occurring in the pipe body <NUM> can be made uniform in the circumferential direction.

(<NUM>) In the exhaust gas pipe <NUM> according to a fifth aspect, the deformation prevention member <NUM> may be provided at a position that coincides with each coupling member <NUM> in the circumferential direction.

According to the above-described configuration, since the deformation prevention member <NUM> is provided at a position in which the tightening force of the coupling member <NUM> is concentrated, the deformation prevention member <NUM> can disperse the tightening force. Accordingly, it is possible to further reduce the possibility of the deformation of the flange <NUM>.

(<NUM>) In the exhaust gas pipe <NUM> according to a sixth aspect, the gasket G may be formed in an annular shape that covers the entire surface of the flange <NUM> and an annular portion on the outer radial side of the gasket G may constitute the deformation prevention member 40b.

According to the above-described configuration, the gasket G covers the entire surface of the flange <NUM>. Further, the outer radial portion of the gasket G functions as the deformation prevention member 40b. Accordingly, the number of parts is reduced and the cost required for manufacturing and maintaining the exhaust gas pipe <NUM> can be reduced.

According to the above-described configuration, when the bolt is tightened, the tightening amount of the bolt is limited by the pipe P. Accordingly, excessive bolt tightening is avoided, and deformation of the flange <NUM> can be prevented.

(<NUM>) The engine <NUM> according to a ninth aspect includes: the exhaust gas pipe <NUM> and the engine body <NUM> which is provided with the combustion chamber <NUM> from which the exhaust gas is sent to the exhaust gas pipe <NUM>.

According to the above-described configuration, it is possible to provide the engine <NUM> provided with the exhaust gas pipe <NUM> in which leakage of an exhaust gas is further reduced.

Claim 1:
An exhaust gas pipe (<NUM>) comprising:
a plurality of pipe bodies (<NUM>) which are formed in a tubular shape centered on an axis (Ac) and are arranged in a direction of the axis (Ac) and through which an exhaust gas led from an engine body (<NUM>) flows;
a connection portion (<NUM>) connecting a pair of the pipe bodies (<NUM>) adjacent to each other in the direction of the axis (Ac); and
a gasket (G) which is provided between the pipe body and the connection portion (<NUM>),
wherein a flange (<NUM>) projecting toward an outer peripheral side is provided at an end portion of the pipe body in the direction of the axis (Ac),
wherein the connection portion (<NUM>) includes a main connection body (<NUM>) which has a tubular shape centered on the axis (Ac) and a pressing ring (<NUM>) which is provided with a facing surface (<NUM>) facing the flange (<NUM>) while sandwiching the gasket (G) in a gap (S) between the flange (<NUM>) and the facing surface (<NUM>), and
wherein the exhaust gas pipe (<NUM>) further comprises:
coupling members (<NUM>) which are provided at intervals in a circumferential direction and coupling the flange (<NUM>) and the pressing ring (<NUM>) to each other; and
a deformation prevention member (<NUM>) that is provided in an outer peripheral region of the gap (S),
characterized in that
the deformation prevention member (<NUM>) includes a tapered portion (<NUM>) of which an axial dimension gradually decreases from an outer radial side to an inner radial side.