JP6742800B2 - Excavator - Google Patents

Description

The present invention relates to excavators.

Exhaust gas discharged from the engine of a hydraulic excavator may contain harmful substances such as nitrogen oxides (NOx). Therefore, conventionally, a hydraulic excavator is equipped with an exhaust gas treatment device which is connected to the engine through a connecting pipe in order to treat the exhaust gas from the engine.

This exhaust gas treatment device includes a diesel particulate filter (DPF) that collects particulate matter (PM) contained in exhaust gas, and a selective reducing agent (for example, urea) that reduces and removes nitrogen oxides (NOx). A selective reduction type catalyst (SCR) and the like, which is reduced and removed by using, is generally used.

A configuration is disclosed in which the exhaust gas treatment device as described above is supported by a support frame body having a fire wall other than the engine (for example, Patent Document 1).

JP, 2014-193664, A

When the exhaust gas treatment device is supported by a supporting frame body other than the engine as in Patent Document 1, it is necessary to provide a bellows portion that absorbs vibration in a connecting pipe that connects the exhaust gas treatment device and the engine.

However, since the bellows portion has a circular wave shape (continuous U shape), noise is generated when the exhaust gas passes through. As a noise countermeasure, sound absorbing material was installed on the outer circumference of the connecting pipe and the cover material around the engine. However, since there is a limited space between the exhaust gas treatment device and the engine, the layout of each member is limited in order to install the sound absorbing material.

In view of the above problems, one object of the present embodiment is to provide a shovel that does not install a sound absorbing material that can secure the degree of freedom of layout of members and effectively reduce noise generated in the bellows portion. ..

An excavator according to an embodiment of the present invention is
An engine installed as a power source,
A support frame body erected on a revolving frame that supports the engine,
An exhaust gas treatment device that is supported by the support frame and that treats exhaust gas from the engine,
Piping for flowing out the exhaust gas from the engine,
And a connecting pipe for connecting the pipe with the exhaust gas treatment device,
The connecting pipe is
At least a shrinkable bellows portion, and an inflow pipe for flowing exhaust gas into the bellows portion,
The inflow pipe is in direct contact with the exhaust gas, and has an entrance portion that enters the inside of the bellows portion,
The bellows portion has an arrangement direction different from the exhaust gas inflow direction from the engine,
The bellows portion and the entrance portion are located on the central axis of the pipe,
The pipe diameter of the inflow pipe is smaller than the pipe inner diameter of the bellows portion,
The engine-side end portion of the bellows portion and the entrance portion are connected at a connection portion,
The end portion of the bellows portion on the engine side, the connection portion, and the entry portion overlap each other when viewed in the radial direction.

According to the disclosed embodiment, it is possible to provide a shovel that does not install a sound absorbing material that can effectively reduce the noise generated in the bellows portion while ensuring the degree of freedom in the layout of the members.

It is a side view of a shovel. It is the top view which looked at the upper revolving superstructure of a shovel from above. It is sectional drawing which shows the engine compartment of a shovel schematically. It is a partial enlarged view explaining the relationship between an exhaust gas treatment device and an exhaust pipe. It is sectional drawing explaining the structure of an exhaust pipe. FIG. 3 is a partially enlarged view of FIG. 2. It is sectional drawing explaining another structure of a connection pipe.

FIG. 1 is a side view showing a hydraulic excavator according to an embodiment of the present invention.

The hydraulic excavator has a crawler-type lower traveling body 1 that is self-propelled, and an upper revolving body 3 that is mounted on the lower traveling body 1 via a revolving mechanism 2 so as to be revolvable.

A boom 4 is attached to the upper swing body 3. An arm 5 is attached to the tip of the boom 4, and a bucket 6 as an end attachment is attached to the tip of the arm 5. The boom 4, the arm 5 and the bucket 6 constitute a work attachment.

The boom 4 is attached to the revolving frame 31 so that the boom 4 can be lifted and lowered. The arm 5 is rotatably attached to the tip end side of the boom 4. The bucket 6 is rotatably attached to the tip side of the arm 5.

The boom cylinder 7 is arranged between the swing frame 31 and the boom 4. The boom cylinder 7 causes the boom 4 to move up and down with respect to the revolving frame 31. The arm cylinder 8 is arranged between the boom 4 and the arm 5. The arm cylinder 8 causes the arm 5 to rotate with respect to the boom 4. Further, the bucket cylinder 9 is arranged between the bucket 6 and the arm 5. The bucket cylinder 9 rotates the bucket 6 with respect to the arm 5.

The upper revolving structure 3 is installed on the lower traveling structure 1 via the revolving mechanism 2 so as to be freely rotatable. As shown in FIGS. 2 and 3 in addition to FIG. 1, the upper revolving structure 3 includes a revolving frame 31, a cab 10, a counterweight 32, an outer cover 33, an engine 11 as a power source, a heat exchange device 40, and a dustproof. The device 50, the exhaust gas treatment device 60, and the like are provided.

The cab 10 is provided on the turning frame 31, and a driver's seat (not shown) is provided inside the cab 10. The operator sits on the driver's seat in the cab 10 and operates the hydraulic excavator.

The counterweight 32 has a function of balancing the weight with the work attachment. The exterior cover 33 and the engine hood 34a cover the engine 11, the heat exchange device 40, the exhaust gas treatment device 60, and the like arranged in the engine compartment 34.

FIG. 2 is a plan view showing a schematic configuration of the upper swing body 3. As shown in FIG. 2, an engine compartment 34 (shown by a chain line) is formed at the rear of the upper swing body 3. The upper portion of the engine compartment 34 is covered with an engine hood 34a as shown in FIG. 1, but FIG. 2 shows a state in which the engine hood 34a is removed in order to illustrate the inside of the engine compartment 34.

As shown in FIG. 2, the engine 11 is installed in the engine compartment 34. An exhaust gas treatment device 60 described later is arranged near the engine 11. The engine 11 is provided with a cooling fan 35, and a heat exchange device 40 including a radiator unit is installed in front of the cooling fan 35 (on the side of arrow X1).

An air cleaner 70 (air filter) is arranged on the side of the heat exchange device 40 (on the front side of the shovel (on the side of the arrow Z2)). The air cleaner 70 is connected to the supercharger 72 via an intake pipe 71. The supercharger 72 is connected to the engine 11. The supercharger 72 forcibly increases the pressure of the air filtered by the air cleaner 70 and supplies the air to the engine 11. The supercharger 72 may be a turbocharger that uses the flow of exhaust gas, a supercharger that compresses intake air with the force of an engine, or the like.

An exhaust pipe 80 for discharging engine exhaust (hereinafter referred to as “exhaust gas”) from the engine 11 is connected to the supercharger 72. By passing the supercharger 72 while flowing from the engine 11 into the exhaust pipe 80, the energy of the exhaust gas can be used to increase the pressure of the air flowing into the engine 11 from the air cleaner 70. At the downstream end of the exhaust pipe 80, an exhaust gas treatment device 60 that complies with higher exhaust gas regulations is installed. In the present embodiment, as the exhaust gas treatment device 60, a urea selective reduction type NOx treatment device using an aqueous urea solution (liquid reducing agent) is used. The exhaust gas treatment device 60 will be described later.

The cab 10 is arranged on the left front part of the upper swing body 3. Here, in the present specification, the front portion of the upper swing body 3 is a portion on the side where the boom 4 is attached as viewed from the center of the upper swing body 3. Further, the front is a direction in which the boom 4 extends as viewed from the center of the upper swing body 3. Further, the left side is a part which becomes the left side when facing forward (the direction in which the boom 4 extends) in the upper swing body 3. Further, the right side is a part that becomes the right side when facing forward (the direction in which the boom 4 extends) in the upper swing body 3.

A fuel tank 73 for storing diesel engine fuel such as light oil is arranged on the right front side of the engine compartment 34. The diesel engine fuel stored in the fuel tank 73 is supplied to the engine 11 via a fuel supply pipe (not shown). A hydraulic oil tank 74 for storing hydraulic oil used in the hydraulic system is arranged in front of the fuel tank 73.

A urea water tank (treatment agent tank) 75 for storing a treatment agent (urea aqueous solution (liquid reducing agent)) used by the exhaust gas treatment device 60 is arranged in front of the hydraulic oil tank 74. The treatment agent stored in the urea water tank 75 is supplied to the exhaust gas treatment device 60 through a treatment agent supply pipe (not shown). The urea aqueous solution (liquid reducing agent) is an example of the treating agent, and other treating agents may be used as the liquid reducing agent, or other treating method may be used.

Next, the configuration inside the engine compartment 34 will be described.
FIG. 3 is a schematic configuration diagram showing an internal configuration of the engine room 34. FIG. 3 is a view of the upper swing body 3 of FIG. 2 as viewed from the rear side (arrow Z1 side).

The engine 11, the heat exchange device 40, the dustproof device 50, the exhaust gas treatment device 60, and the like are arranged in the engine compartment 34.

The engine 11 is supported above the engine mounting seat 31a arranged on the revolving frame 31 via a mount 31b. The mount 31b is an anti-vibration mount and prevents the vibration generated in the engine 11 from being transmitted to the revolving frame 31.

A cooling fan 35 is arranged on the X1 side (left side in the figure) of the engine 11. A heat exchange device 40 is arranged on the X1 side of the cooling fan 35. Further, a dustproof device 50 is arranged on the X1 side of the heat exchange device 40. The dustproof device 50 includes a pair of brackets 51 and a dustproof net 52.

The cooling fan 35 is rotationally driven by the engine 11. When the cooling fan 35 is rotationally driven, the outside air is taken into the engine compartment 34 as the cooling wind W from the intake port provided in the maintenance door 33A. The heat exchange device 40 performs heat exchange processing (cooling processing) with the cooling air W taken into the engine compartment 34.

The cooling air W flows in the right direction in the figure as indicated by the arrow in FIG. Therefore, in the figure, the X1 side is the cooling air upstream side, and the X2 side is the cooling air downstream side. Further, in the present embodiment, the Y1 direction in the drawing is the upward direction and the Y2 direction in the drawing is the downward direction.

The heat exchange device 40 is configured such that each heat exchanger such as a radiator unit 40A, a fuel cooler 40B, a condenser 40C, an oil cooler 40D, and an intercooler 40E is integrally unitized.

The radiator unit 40A cools the cooling water flowing in the engine 11. The fuel cooler 40B cools the excess fuel returning to the fuel tank (not shown). The condenser 40C is for generating cold air in the air conditioner mounted on the cab 10. The oil cooler 40D cools the hydraulic oil of hydraulic equipment such as various cylinders 7, 8 and 9. The intercooler 40E cools the supercharged air supplied to the engine 11. Various refrigerants such as cooling water and hydraulic oil flowing into each of the heat exchangers 40A to 40E are cooled by the cooling air W.

A hydraulic pump 14 is integrally attached to the X2 side of the engine 11. The hydraulic pump 14 is a hydraulic source such as a boom cylinder 7, an arm cylinder 8 and a bucket cylinder 9 that drive the work attachment. The hydraulic pump 14 is also driven by the engine 11.

The exhaust gas discharged from the engine 11 is purified by the exhaust gas processing device 60. Exhaust gas discharged from the engine 11 may contain harmful substances such as nitrogen oxides (NOx), and in order to purify them, the engine 11 includes an exhaust gas treatment device 60 as an exhaust pipe as a connecting pipe. It is connected via 80.

Next, the exhaust gas treatment device 60 and the exhaust pipe 80 will be described with reference to FIGS. 3 and 4. FIG. 4 is a partially enlarged view of the exhaust gas treatment device 60 and the exhaust pipe 80 viewed from the rear side of FIG. Note that the engine 11 is omitted for the sake of explanation.

In the exhaust gas treatment device 60, a first processing unit 61 in which an oxidation catalyst for burning fine particles in exhaust gas is arranged, and a nitrogen oxide (NOx) in the exhaust gas from which fine particles are removed is a reducing agent (for example, urea). And a selective reduction type catalyst 62 (SCR) as a second processing unit for reducing and removing by using. As the first processing unit 61, a diesel particulate filter (DPF) that collects particulate matter (PM) contained in the exhaust gas may be used. The first processing section 61 and the selective reduction catalyst 62 are connected by a connecting section 63.

The first processing unit 61 includes a pre-stage oxidation catalyst on the upstream side thereof, and the selective reduction catalyst 62 includes a post-stage oxidation catalyst on the downstream side thereof. The first processing unit 61 can also be an oxidation catalyst supporting filter (CSF).

The exhaust pipe 80 connects the first processing unit 61 that constitutes the exhaust gas processing device 60 and the supercharger 72 (on the engine 11 side).

The exhaust gas treatment device 60 configured as described above is supported by the support frame 36 having the support 37, the fire wall 42, and the like, and is arranged above the hydraulic pump 14 and at a position separated from the engine 11. The support frame body 36 is erected on the swivel frame 31.

The heat exchange device 40 and the dustproof device 50 equipped with the dustproof net 52 are fixed on the upstream side of the cooling fan 35 with respect to the flow direction of the cooling air W in the engine compartment 34, as shown in FIG.

A fixed base 38 is formed at the position where the heat exchange device 40 and the dustproof device 50 are arranged on the swivel frame 31. The fixed base 38 is formed so as to project from the floor surface of the revolving frame 31. The heat exchange device 40 is fixed on the fixed base 38. When the heat exchange device 40 is fixed to the engine compartment 34, the upper portion of the dustproof device 50 is covered with the engine hood 34a. The engine hood 34a is configured to be openable/closable with respect to the exterior cover 33.

The dustproof device 50 is arranged upstream of the heat exchange device 40 with respect to the flow direction of the cooling air W. Since the dustproof device 50 performs the dustproof treatment on each of the heat exchangers 40A to 40E constituting the heat exchange device 40, it is possible to prevent clogging from occurring in all the heat exchangers 40A to 40E.

Next, the exhaust pipe 80 that connects the supercharger 72 and the exhaust gas treatment device 60 will be described in more detail with reference to FIGS. 4 and 5. FIG. 5 is a vertical cross-sectional view of the exhaust pipe 80 shown in FIG.

The exhaust pipe 80 of the present embodiment has a split structure including an inflow pipe 81, a bellows pipe 82 as a bellows portion, and an outflow pipe 83.

The bellows pipe 82 is provided in the exhaust pipe 80 of the present embodiment, for example, because of the following points. As shown in FIG. 3, when the exhaust gas treatment device 60 is supported by the support frame body 36 other than the engine, the exhaust gas treatment device 60 is greatly affected by vibration from the support frame body 36. On the other hand, the exhaust pipe 80 connecting the exhaust gas treatment device 60 and the supercharger 72 is greatly affected by the vibration from the engine 11. Therefore, the vibration difference between the engine 11 and the support frame 36 acts on the exhaust pipe 80. This vibration difference can be absorbed by the bellows pipe 82 provided in the exhaust pipe 80.

The inflow pipe 81 is joined to the end of the bellows pipe 82 of the present embodiment on the engine 11 side by welding. The outflow pipe 83 is joined by welding to the exhaust gas treatment device 60 side of the bellows pipe 82. Therefore, the exhaust pipe 80 can discharge the exhaust gas discharged from the engine 11 to the first processing unit 61 of the exhaust gas processing device 60. The bellows pipe 82 is supported by the inflow pipe 81. Further, the bellows pipe 82 may be supported by the outflow pipe 83.

The inflow pipe 81 is connected to the supercharger 72 that discharges the exhaust gas from the engine 11. A flange portion 810 is provided at the end of the inflow pipe 81 on the engine 11 side. A flange portion 720 is provided at an end portion of the supercharger 72 on the inflow pipe 81 side. The inflow pipe 81 and the supercharger 72 are connected by bolting flange portions 810 and 720.

The outflow pipe 83 is connected to the exhaust gas treatment device 60 (first treatment unit 61). A flange portion 830 is provided at the end portion of the outflow pipe 83 on the exhaust gas treatment device 60 side. A flange portion 610 is provided at the end portion of the exhaust gas treatment device 60 on the outflow pipe 83 side. The outflow pipe 83 and the exhaust gas treatment device 60 are connected to each other by bolting flange portions 830 and 610.

The inflow pipe 81 has a taper portion 811 whose diameter decreases toward the exhaust gas treatment device 60 side. The inflow pipe 81 of the present embodiment is configured such that the tapered portion 811 enters the inside of the bellows pipe 82. The taper portion 811 of the present embodiment is an example of an entrance portion that enters the inside of the bellows pipe 82. Therefore, the pipe diameter D1 of the end portion of the inflow pipe 81 on the tapered portion 811 side is smaller than the pipe inner diameter D2 of the bellows pipe 82. The outflow pipe 83 does not enter the bellows pipe 82. The diameters of the inflow pipe 81 other than the tapered portion 811 are the same as the diameters of the bellows pipe 82 and the outflow pipe 83.

The bellows pipe 82 has a flexible portion 820, and the flexible portion 820 absorbs vibration of the engine 11 and the exhaust gas treatment device 60. The flexible portion 820 is formed by a plurality of continuous U-shapes provided so as to project outward.

The exhaust gas flowing into the inflow pipe 81 has a large flow rate and a high flow rate due to the immediately preceding supercharger 72. In the inflow pipe 81 of the present embodiment, the tapered portion 811 is configured to enter the bellows pipe 82, so that exhaust gas having a fast flow is guided in the arrow direction in which it does not hit the inner wall of the flexible portion 820 of the bellows pipe 82. .. Therefore, the noise generated when the exhaust gas enters the U-shaped portion of the flexible portion 820 of the bellows pipe 82 can be reduced.

The length L of penetration of the tapered portion 811 into the bellows pipe 82 is preferably 0.1 to 0.8 times the length H of the bellows pipe 82 in the axial direction. The approach length L is appropriately changed depending on the flow rate of exhaust gas. Further, the axial length H of the bellows pipe 82 is preferably 1 to 5 times the pipe inner diameter D3 of the end of the inflow pipe 81 on the side of the tapered portion 811.

By setting the axial length H of the bellows tube 82 and the entry length L into the bellows tube 82 in the above-described relationship, the axial misalignment between the inflow pipe 81 and the outflow pipe 83 can be minimized. Further, the supporting force and durability of the bellows tube 82 can be maintained.

Next, the installation angle of the bellows tube 82 will be described with reference to FIGS. 2 and 6. FIG. 6 is a partially enlarged view of FIG. 2, and the bellows pipe 82 is made transparent for the sake of explanation.

As shown in FIGS. 2 and 6, the bellows pipe 82 of the present embodiment can be arranged at an angle (tilt) on the rear side (arrow Z1 direction) with respect to the exhaust gas inflow direction J from the engine 11. In the illustrated example, the entire exhaust pipe 80 is arranged at an angle (tilt) with respect to the exhaust gas inflow direction J from the engine 11.

To secure the space in the engine compartment 34, a layout in which the exhaust gas treatment device 60 is arranged on the rear side (arrow Z1 side) as shown in FIG. 2 is effective. However, when the engine 11 (supercharger 72) and the exhaust gas treatment device 60 are laid out as shown in FIG. 2, the exhaust pipe must be arranged at an angle with respect to the exhaust gas inflow direction J. However, when the exhaust pipe having the conventional bellows pipe is used, the exhaust gas flowing into the exhaust pipe directly hits the bellows pipe, which causes a problem of noise. Therefore, in order to use a straight pipe extending in the same direction as the exhaust gas inflow direction J, the exhaust port of the supercharger 72 (including the engine 11) and the inflow port of the exhaust gas treatment device 60 are coaxially arranged. Was. Therefore, the layout of the supercharger 72 (engine 11) and the exhaust gas treatment device 60 is limited, and space loss occurs in the engine compartment 34.

However, the exhaust pipe 80 of the present embodiment is configured such that the tapered portion 811 of the inflow pipe 81 enters the bellows pipe 82 as described above.

Therefore, even if the bellows pipe 82 is arranged at an angle with respect to the exhaust gas inflow direction J, the exhaust gas having a fast flow hits the tapered portion 811 of the inflow pipe 81 and does not hit the inner wall of the flexible portion 820 of the bellows pipe 82. Since it is guided in the direction of the arrow, noise can be reduced.

From the above point, the exhaust pipe 80 of the present embodiment can reduce the generation of noise due to the bellows pipe 82 while ensuring the freedom of layout of the supercharger 72 and the exhaust gas treatment device 60.

Further, since the exhaust pipe 80 of the present embodiment has a structure that has a sound deadening structure inside the exhaust pipe, it is economical because it is not necessary to install conventionally used members such as a sound absorbing material and a sound deadening cover. Further, since the sound absorbing material has a low durability because it is installed in a high-heated place and easily contains water, and maintenance work such as replacement is required. However, in the present embodiment, such maintenance work is unnecessary.

Next, another embodiment will be described with reference to FIG. Another embodiment has substantially the same technical idea as the embodiments shown in FIGS. 1 to 6, and common points will be omitted and the different points will be mainly described.

The exhaust pipe 90 of the present embodiment has a split structure including an inflow pipe 91, a bellows pipe 92 as a bellows portion, and an outflow pipe 93.

An inflow pipe 91 is welded to an end of the bellows pipe 92 on the engine 11 side via a ring-shaped positioning member 94. An outflow pipe 93 is welded and joined to the exhaust gas treatment device 60 side of the bellows pipe 92 via a positioning member 95. Therefore, the exhaust pipe 90 can discharge the exhaust gas discharged from the engine 11 to the first processing unit 61 of the exhaust gas processing device 60.

The inflow pipe 91 and the supercharger 72 are connected by bolting flange portions 910 and 720. The outflow pipe 93 and the exhaust gas treatment device 60 are connected by bolting the flange portions 930 and 610.

The inflow pipe 91 is configured to have an entrance portion 911 that enters the inside of the bellows pipe 92. The penetration length L2 of the entrance portion 911 into the bellows tube 92 is preferably 0.1 to 0.8 times the axial length H2 of the bellows tube 92. The entry length L2 is appropriately changed depending on the flow rate of exhaust gas and the like. Further, the axial length H2 of the bellows tube 92 is preferably 1 to 5 times the tube inner diameter D4 of the inflow tube 91. The outflow pipe 93 does not enter the bellows pipe 92.

The exhaust pipe 90 of the present embodiment has a configuration in which the inflow pipe 91 does not have the tapered portion shown in FIG. If the inflow pipe is provided with a tapered portion, the exhaust pressure in the inflow pipe increases. When the allowable exhaust pressure in the inflow pipe is set low, it is desirable to implement the exhaust pipe 90 without the tapered portion to ensure the exhaust gas treatment performance of the exhaust gas treatment device 60 and the performance of the engine 11. ..

In the exhaust pipe 90 of the present embodiment, the pipe diameter D5 of the bellows pipe 92 is made larger than the pipe diameter D6 of the inflow pipe 91 and the pipe diameter D7 of the outflow pipe 93. The pipe diameter D6 of the inflow pipe 91 and the pipe diameter D7 of the outflow pipe 93 may be the same.

The exhaust gas that has flowed into the inflow pipe 91 from the engine 11 is directly discharged into the bellows pipe 92 by the entry portion 911. Since the bellows pipe 92 has a pipe diameter D5 which is larger than the pipe diameter D6 of the inflow pipe 91, the exhaust gas flowing from the inflow portion 911 of the inflow pipe 91 is guided in the arrow direction where it does not hit the inner wall of the flexible portion 920. To be done. Therefore, noise generated when exhaust gas hits the flexible portion 920 of the bellows pipe 92 can be effectively reduced.

Although the preferred embodiments of the present invention have been described above in detail, the present invention is not limited to the above-described specific embodiments, and various modifications are possible within the scope of the gist of the present invention described in the claims. Modifications and changes are possible.

1... Lower traveling body 2... Revolving mechanism 3... Upper revolving structure 31... Revolving frame 32... Counterweight 33... Exterior cover 33A... Maintenance door 34... Engine room 34a... Engine hood 35... Cooling fan 36... Support frame 37... Support 38... Fixing base 4... Boom 5... Arm 7... Boom cylinder 8.... -Arm cylinder 9... Bucket cylinder 11... Engine 40... Heat exchange device 50... Dustproof device 60... Exhaust gas treatment device 61... First treatment unit 62... Selective reduction catalyst 80... Exhaust pipe (connection pipe) 81... Inflow pipe 811... Tapered portion 82... Bellows pipe (bellows portion) 820... Flexible portion 83... Outflow pipe H... Axial length of bellows tube J・・・Exhaust gas entry direction L・・・Entry length W・・・Cooling air

Claims (6)

An engine installed as a power source,
A support frame body erected on a revolving frame that supports the engine,
An exhaust gas treatment device that is supported by the support frame and that treats exhaust gas from the engine,
Piping for flowing out the exhaust gas from the engine,
And a connecting pipe for connecting the pipe with the exhaust gas treatment device,
The connecting pipe is
At least a shrinkable bellows portion, and an inflow pipe for flowing exhaust gas into the bellows portion,
The inflow pipe is in direct contact with the exhaust gas, and has an entrance portion that enters the inside of the bellows portion,
The bellows portion has an arrangement direction different from the exhaust gas inflow direction from the engine,
The bellows portion and the entrance portion are located on the central axis of the pipe,
The pipe diameter of the inflow pipe is smaller than the pipe inner diameter of the bellows portion,
The engine-side end portion of the bellows portion and the entry portion are connected at a connection portion,
The shovel, wherein the engine-side end portion of the bellows portion, the connection portion, and the entrance portion overlap each other when viewed in the radial direction. The outlet side end portion of the entrance portion is located closer to the engine than the center of the bellows portion,
The shovel according to claim 1, wherein The excavator according to claim 1 or 2, wherein the entrance portion has a shape in which the pipe diameter decreases toward the exit side. The length of penetration of the inflow pipe into the bellows portion is 0.1 to 0.8 times the axial length of the bellows portion,
The shovel according to claim 1, wherein an axial length of the bellows portion is 1 to 5 times the inner diameter of the inlet portion of the inflow pipe. The excavator according to claim 3, wherein the shape is configured integrally with the inflow pipe. The connecting pipe is
Further having an outflow pipe for outflowing the exhaust gas from the bellows portion,
The inflow pipe is joined by welding to the engine side of the bellows part, and the outflow pipe is joined by welding to the exhaust gas treatment device side of the bellows part. The excavator according to any one of claims.

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