Work vehicle

Abstract

To decrease a temperature of exhaust of an engine when an outlet of a first exhaust pipe and an inlet of a second exhaust pipe are arranged close to each other, in a service vehicle.SOLUTION: A service vehicle comprises a first exhaust pipe through which exhaust of an engine is sent, and a second exhaust pipe 12 provided with an inlet 14 having a larger outer diameter than an outlet 13 of the first exhaust pipe. The outlet 13 of the first exhaust pipe and the inlet 14 of the second exhaust pipe 12 are arranged close to each other so that the outlet 13 of the first exhaust pipe is arranged inside the inlet 14 of the second exhaust pipe 12. The service vehicle comprises partition members 16, 17 that divide an area of the outlet 13 of the first exhaust pipe into a plurality of divided areas B1 and partitions the adjacent divided areas B1 at intervals when viewed from a direction where the exhaust emitted from the outlet 13 of the first exhaust pipe flows.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an exhaust configuration for an engine in a work vehicle. [Background technology]

[0002] For example, in a work vehicle such as a tractor used in an orchard, livestock barn, etc., a work vehicle equipped with an engine may have a muffler installed under the body due to restrictions on the height of the body, etc. In this case, in an environment such as an orchard or livestock barn, combustible materials such as fallen leaves may accumulate on the ground, so it is desirable to lower the temperature of the engine exhaust gas coming out of the muffler.

[0003] 2. Description of the Related Art In a tractor, which is an example of a work vehicle, there is a structure disclosed in Patent Document 1 that reduces the temperature of the exhaust gas from the engine. In Patent Document 1, a first exhaust pipe to which engine exhaust is delivered and a second exhaust pipe having an inlet with a larger outer diameter than the outlet of the first exhaust pipe are provided, and the outlet of the first exhaust pipe and the inlet of the second exhaust pipe are arranged close to each other so that the outlet of the first exhaust pipe is located inside the inlet of the second exhaust pipe.

[0004] When the engine exhaust leaves the outlet of the first exhaust pipe and enters the inside of the second exhaust pipe through the inlet of the second exhaust pipe, outside air is drawn into the engine exhaust flow due to the ejector effect, is introduced into the inside of the second exhaust pipe through the inlet of the second exhaust pipe, and mixes with the engine exhaust, causing the temperature of the engine exhaust to be lowered by the outside air. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-153304 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the above-described configuration, in order to introduce a large amount of outside air to lower the temperature of the engine exhaust, it is preferable to increase the flow velocity of the engine exhaust at the outlet of the first exhaust pipe, and it is preferable to increase the area (boundary surface) where the engine exhaust flow comes into contact with the outside air at the outlet of the first exhaust pipe.

[0007] In Patent Document 1, in order to increase the flow velocity of the engine exhaust at the outlet of the first exhaust pipe, the outlet of the first exhaust pipe is narrowed into a flat shape to increase the flow velocity of the engine exhaust. However, if the outlet of the first exhaust pipe is narrowed too much, the disadvantage of increasing the exhaust back pressure of the engine becomes significant.

[0008] In order to increase the area (boundary surface) where the engine exhaust flow comes into contact with the outside air, it is possible to enlarge the diameter of the outlet of the first exhaust pipe and the inlet of the second exhaust pipe, or to provide multiple configurations in which the outlet of the first exhaust pipe and the inlet of the second exhaust pipe are positioned close to each other; however, this is not preferable as it would result in a larger and more complicated structure.

[0009] The present invention aims to configure a work vehicle in which, when the outlet of a first exhaust pipe and the inlet of a second exhaust pipe are positioned close to each other, a large amount of outside air is drawn into the engine exhaust flow and mixed with the engine exhaust without unnecessarily narrowing the outlet of the first exhaust pipe, thereby lowering the temperature of the engine exhaust. [Means for solving the problem]

[0010] The work vehicle of the present invention is provided with a first exhaust pipe to which engine exhaust is delivered, and a second exhaust pipe provided with an inlet having an outer diameter larger than the outlet of the first exhaust pipe, the outlet of the first exhaust pipe and the inlet of the second exhaust pipe are disposed close to each other so that the outlet of the first exhaust pipe is disposed inside the inlet of the second exhaust pipe when viewed from the direction of exhaust flow from the outlet of the first exhaust pipe, and a partition member is provided which divides an area of ​​the outlet of the first exhaust pipe into a plurality of divided areas and separates adjacent divided areas at intervals when viewed from the direction of exhaust flow from the outlet of the first exhaust pipe. When viewed from a direction perpendicular to the direction of the exhaust flow exiting the outlet of the first exhaust pipe, the cross-sectional shape of the partition member is formed into a wedge shape that tapers toward the upstream side of the exhaust flow exiting the outlet of the first exhaust pipe.

[0011] According to the present invention, in a configuration in which the outlet of a first exhaust pipe and the inlet of a second exhaust pipe are arranged close to each other so that the outlet of the first exhaust pipe is located inside the inlet of the second exhaust pipe when viewed from the direction of the exhaust flow exiting the outlet of the first exhaust pipe, the area of ​​the outlet of the first exhaust pipe is divided into a plurality of divided areas by a partition member, and adjacent divided areas are separated at intervals by the partition member.

[0012] According to the present invention, when the engine exhaust exits the outlet of the first exhaust pipe, the engine exhaust flow passes through the multiple division regions formed by the partition member and is divided into multiple flows corresponding to the division regions. Immediately after the partition member, the multiple engine exhaust flows become independent flows, and then the multiple engine exhaust flows are mixed with outside air and then merge. At the same time, the area of ​​the outlet of the first exhaust pipe is narrowed by the partition member, so that the flow speed of the multiple engine exhaust flows is increased.

[0013] According to the present invention, the outer periphery of the divided area becomes the boundary surface in each of the multiple engine exhaust flows, so that the sum of the boundary surfaces of the multiple engine exhaust flows becomes the boundary surface of the engine exhaust when a partition member is provided. In contrast to this, when no partition member is provided, the boundary surface of the engine exhaust is the outer periphery of the outlet of the first exhaust pipe. Therefore, the boundary surface of the engine exhaust when the partition member is provided is greater than the boundary surface of the engine exhaust when the partition member is not provided.

[0014] As described above, according to the present invention, by providing a partition member, it is possible to increase the boundary surface area of ​​the engine exhaust while appropriately increasing the flow speed of the engine exhaust, so that a large amount of outside air can be drawn into the engine exhaust flow, introduced into the inside of the second exhaust pipe from the inlet of the second exhaust pipe, and mixed into the engine exhaust, thereby lowering the temperature of the engine exhaust. According to the present invention, when the engine exhaust flow is divided into a plurality of divided regions by the partition member, the cross-sectional shape of the partition member is wedge-shaped, so that the engine exhaust flow is guided along the partition member, and a space where the engine exhaust does not flow is easily generated in the region downstream of the partition member, and the aforementioned space tends to expand toward the downstream side. As a result, outside air easily enters the space where the engine exhaust does not flow, and it is expected that the temperature of the engine exhaust can be efficiently lowered. In the present invention, it is preferable that a gap be provided between the outlet of the first exhaust pipe and the inlet of the second exhaust pipe when viewed from a direction perpendicular to the direction of the exhaust flow issuing from the outlet of the first exhaust pipe.

[0015] In the present invention, it is preferable that the partition member is attached to an outlet of the first exhaust pipe.

[0016] According to the present invention, the partition member is attached to the outlet of the first exhaust pipe, spanning from one part of the outer periphery of the outlet to another part of the outer periphery, so that the outlet of the first exhaust pipe is reinforced by the partition member.

[0017] In the present invention, it is preferable that the partition member is formed so that the areas of the plurality of divided regions are the same when viewed from a flow direction of the exhaust gas exiting the outlet of the first exhaust pipe.

[0018] According to the present invention, when the engine exhaust flow is divided into multiple flows by a partition member as described above, the areas of the multiple divided regions by the partition member are the same, and the boundary surfaces in each of the multiple engine exhaust flows are approximately the same, so that it is expected that outside air will be mixed approximately evenly into each of the multiple engine exhaust flows, and that the temperature of the engine exhaust will drop approximately evenly in each of the multiple engine exhaust flows. As a result, when the engine exhaust flow is split into multiple flows by the partition member and then rejoins the multiple flows, it is expected that the temperature of the engine exhaust will decrease approximately evenly.

[0019] In the present invention, it is preferable that the partition members are formed and arranged radially outward from the center of the outlet of the first exhaust pipe when viewed from the direction of the flow of exhaust gas leaving the outlet of the first exhaust pipe.

[0020] According to the present invention, the partition members are formed so as to be radially arranged, so that the partition members can be simply formed while being provided with sufficient strength.

[0021] In the present invention, it is preferable that the partition member is formed by opening a plurality of openings in a flat plate-shaped member.

[0022] According to the present invention, the partition member is formed in a flat plate shape with a plurality of openings, so that the partition member can be simply formed while having sufficient strength.

[0023] In the present invention, it is preferable that the partition member is formed symmetrically with respect to an imaginary line passing through the center of the outlet of the first exhaust pipe when viewed from the direction of the flow of exhaust gas exiting the outlet of the first exhaust pipe.

[0024] According to the present invention, since outside air is mixed into the engine exhaust gas along the axisymmetric partition members, it is expected that the temperature of the engine exhaust gas will be reduced approximately evenly.

[0025] The work vehicle of the present invention is provided with a first exhaust pipe to which engine exhaust is delivered, and a second exhaust pipe having an inlet having an outer diameter larger than that of the outlet of the first exhaust pipe, and when viewed from the direction of the flow of exhaust gas leaving the outlet of the first exhaust pipe, the outlet of the first exhaust pipe is disposed inside the inlet of the second exhaust pipe. and a gap is provided between the outlet of the first exhaust pipe and the inlet of the second exhaust pipe when viewed from a direction perpendicular to the direction of the flow of exhaust gas from the outlet of the first exhaust pipe. The outlet of the first exhaust pipe and the inlet of the second exhaust pipe are arranged close to each other so that the outlet of the first exhaust pipe and the inlet of the second exhaust pipe are arranged close to each other, and a cutout portion is formed on the outer periphery of the outlet of the first exhaust pipe, extending from the end of the outlet of the first exhaust pipe to the opposite side of the second exhaust pipe.

[0026] According to the present invention, in a configuration in which the outlet of the first exhaust pipe and the inlet of the second exhaust pipe are arranged close to each other so that the outlet of the first exhaust pipe is located inside the inlet of the second exhaust pipe when viewed from the direction of the exhaust flow exiting the outlet of the first exhaust pipe, a cutout portion is formed on the outer periphery of the outlet of the first exhaust pipe so as to extend from the end of the outlet of the first exhaust pipe to the opposite side of the second exhaust pipe.

[0027] According to the present invention, when the engine exhaust exits from the outlet of the first exhaust pipe, the engine exhaust also exits from the cutout, so that the outer periphery of the cutout also becomes a boundary surface. In this case, the cutout extends from the end of the outlet of the first exhaust pipe to the opposite side of the second exhaust pipe, so that the outer periphery of the cutout is long. In contrast, when no cutout is provided, the boundary surface of the engine exhaust is the outer periphery of the outlet of the first exhaust pipe. Therefore, the boundary surface of the exhaust of the engine with the cutout is greater than the boundary surface of the exhaust of the engine without the cutout.

[0028] As described above, according to the present invention, by providing a cutout portion, it is possible to increase the boundary surface area of ​​the engine exhaust, so that a large amount of outside air can be drawn into the engine exhaust flow, introduced into the inside of the second exhaust pipe from the inlet of the second exhaust pipe, and mixed into the engine exhaust, thereby lowering the temperature of the engine exhaust.

[0029] In the present invention, it is preferable that a plurality of the cutout portions are formed around the entire outer periphery of the outlet of the first exhaust pipe.

[0030] According to the present invention, the outer periphery of the cutout portion that serves as the boundary surface is increased, so that the boundary surface of the engine exhaust can be further increased when the cutout portion is provided. Since the multiple cutout portions are formed around the entire circumference of the outer periphery of the outlet of the first exhaust pipe, the boundary surface is increased approximately evenly around the entire circumference of the outer periphery of the outlet of the first exhaust pipe. This makes it possible to expect outside air to be mixed in approximately evenly from the entire circumference of the engine exhaust flow, and therefore to expect the temperature of the engine exhaust to drop approximately evenly.

[0031] In the present invention, it is preferable that the cutout portion is formed symmetrically with respect to a virtual line passing through a center of the outlet of the first exhaust pipe when viewed from the direction of the flow of exhaust gas exiting the outlet of the first exhaust pipe.

[0032] According to the present invention, it is expected that the temperature of the engine exhaust gas will be reduced approximately evenly by mixing the outside air with the engine exhaust gas along the line-symmetrical cutout portions.

[0033] The work vehicle of the present invention is provided with a first exhaust pipe to which engine exhaust is delivered, and a second exhaust pipe having an inlet with an outer diameter larger than the outlet of the first exhaust pipe, the outlet of the first exhaust pipe and the inlet of the second exhaust pipe are arranged close to each other so that, when viewed from the direction of exhaust flow exiting the outlet of the first exhaust pipe, the outlet of the first exhaust pipe is located inside the inlet of the second exhaust pipe, and a partition member is provided which divides the area of ​​the outlet of the first exhaust pipe into a plurality of divided areas and separates adjacent divided areas at intervals, and a cutout portion is formed on the outer periphery of the outlet of the first exhaust pipe, extending from the end of the outlet of the first exhaust pipe to the opposite side of the second exhaust pipe.

[0034] According to the present invention, in a configuration in which the outlet of the first exhaust pipe and the inlet of the second exhaust pipe are disposed close to each other so that the outlet of the first exhaust pipe is disposed inside the inlet of the second exhaust pipe when viewed from the direction of the exhaust flow from the outlet of the first exhaust pipe, the area of ​​the outlet of the first exhaust pipe is divided into a plurality of divided areas by a partition member, and adjacent divided areas are partitioned at intervals by the partition member. A notch is formed on the outer periphery of the outlet of the first exhaust pipe so as to extend from the end of the outlet of the first exhaust pipe to the opposite side of the second exhaust pipe.

[0035] According to the present invention, when the engine exhaust exits the outlet of the first exhaust pipe, the engine exhaust flow passes through the multiple divided regions formed by the partition member and is divided into multiple flows corresponding to the divided regions. Immediately after the partition member, the multiple engine exhaust flows become independent of each other, and then the multiple engine exhaust flows are mixed with outside air and then merge. At the same time, the area of ​​the outlet of the first exhaust pipe is narrowed by the partition member, so that the flow speed of the multiple engine exhaust flows is increased. When the engine exhaust exits the outlet of the first exhaust pipe, the engine exhaust also exits from the cutout portion.

[0036] According to the present invention, the outer periphery of the divided area becomes the boundary surface in each of the multiple engine exhaust flows, so that the sum of the boundary surfaces of the multiple engine exhaust flows becomes the boundary surface of the engine exhaust when a partition member is provided. When the engine exhaust exits from the outlet of the first exhaust pipe, the engine exhaust also exits from the cutout, so the outer periphery of the cutout also becomes a boundary surface. In this case, the cutout extends from the end of the outlet of the first exhaust pipe to the opposite side of the second exhaust pipe, so that the outer periphery of the cutout is long. According to the present invention, the boundary surface of the engine exhaust when the partition member is provided and the boundary surface of the engine exhaust when the cutout portion is provided are added together.

[0037] In contrast to this, when the partition member and the cutout portion are not provided, the boundary surface of the engine exhaust is the outer periphery of the outlet of the first exhaust pipe. Therefore, the boundary surface area of ​​the exhaust gas from the engine when the partition member and the cutout portion are provided is greater than the boundary surface area of ​​the exhaust gas from the engine when the partition member and the cutout portion are not provided.

[0038] As described above, according to the present invention, by providing the partition member and the cutout portion, it is possible to increase the boundary surface area of ​​the engine exhaust while appropriately increasing the flow speed of the engine exhaust, so that a large amount of outside air can be drawn into the engine exhaust flow, introduced into the interior of the second exhaust pipe from the inlet of the second exhaust pipe, and mixed into the engine exhaust, thereby lowering the temperature of the engine exhaust.

[0039] In the present invention, the partition member is tube In the present invention, it is preferable that the exhaust pipe is attached across a portion of the cutout portion that is farther away from the opposite end of the second exhaust pipe than the opposite end of the second exhaust pipe and the outlet end of the first exhaust pipe, and that the cutout portion protrudes from the outlet end of the first exhaust pipe towards the second exhaust pipe.

[0040] According to the present invention, the partition member is formed to be long in the direction of the exhaust flow exiting the outlet of the first exhaust pipe. Therefore, when the engine exhaust flow is divided into multiple flows by the partition member as described above, the multiple engine exhaust flows tend to become independent of each other. This is advantageous in that the outer periphery of the divided region becomes the boundary surface in each of a plurality of flows of exhaust gas from the engine.

[0041] In the present invention, it is preferable that the partition member and the cutout portion are formed symmetrically with respect to a virtual line passing through a center of the outlet of the first exhaust pipe when viewed from the direction of the flow of exhaust gas exiting the outlet of the first exhaust pipe.

[0042] According to the present invention, since outside air mixes with the engine exhaust gas along the axisymmetric partition members and cutout portions, it is expected that the temperature of the engine exhaust gas will be reduced approximately evenly.

[0043] In the present invention, it is preferable that, when viewed from a direction perpendicular to the direction of the exhaust flow exiting the outlet of the first exhaust pipe, the cross-sectional shape of the partition member is formed into a wedge shape that tapers toward the upstream side of the exhaust flow exiting the outlet of the first exhaust pipe.

[0044] According to the present invention, when the engine exhaust flow is divided into a plurality of divided regions by the partition member, the cross-sectional shape of the partition member is wedge-shaped, so that the engine exhaust flow is guided along the partition member, and a space where the engine exhaust does not flow is easily generated in the region downstream of the partition member, and the aforementioned space tends to expand toward the downstream side. As a result, outside air easily enters the space where the engine exhaust does not flow, and it is expected that the temperature of the engine exhaust can be efficiently lowered. [Brief description of the drawings]

[0045] [Figure 1] FIG. [Diagram 2] 2 is a side view of the exhaust purification device, the first exhaust pipe, the second exhaust pipe, and the vicinity thereof. FIG. [Diagram 3] FIG. 2 is a cross-sectional plan view of the vicinity of the outlet of the first exhaust pipe, the inlet of the second exhaust pipe, and the partition member. [Figure 4] FIG. 4 is a side view of the vicinity of the outlet of the first exhaust pipe and the partition member. [Diagram 5]FIG. 4 is a bottom view of the vicinity of the outlet of the first exhaust pipe and the partition member. [Figure 6] FIG. 2 is a schematic diagram showing divided regions. [Figure 7] FIG. 13 is a perspective view of the vicinity of the outlet of a first exhaust pipe and a partition member in a third alternative embodiment of the invention. [Figure 8] FIG. 13 is a perspective view of the vicinity of the outlet of a first exhaust pipe and a partition member in a fourth modified embodiment of the invention. [Figure 9] FIG. 13 is a perspective view of the vicinity of the outlet and the cutout portion of a first exhaust pipe in a fifth alternative embodiment of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0046] 1 to 9 show a tractor, which is an example of a work vehicle, in which F indicates the forward direction, B indicates the rearward direction, U indicates the upward direction, and D indicates the downward direction.

[0047] (Overall configuration of the tractor) As shown in Fig. 1, an aircraft body 3 is supported by right and left front wheels 1 and right and left rear wheels 2. A diesel engine 4 is provided at the front of the aircraft body 3, and a driver's section 5 is provided at the rear of the aircraft body 3. A driver's seat 6 and a steering handle 7 for the front wheels 1 are provided at the driver's section 5. An arch-shaped rope frame 8 is provided between the engine 4 and the driver's section 5.

[0048] (Arrangement of the first and second exhaust pipes) 1 and 2, the exhaust gas of the engine 4 is supplied to an exhaust gas purification device (not shown) (DPF) to remove particulates from the exhaust gas of the engine 4. The exhaust gas of the engine 4 is then supplied from the exhaust gas purification device (DPF) to an exhaust gas purification device 9 (SCR) to remove nitrogen oxides from the exhaust gas of the engine 4.

[0049] The exhaust purification device 9 is disposed in the left-right direction between the engine 4 and the driver's section 5 (the steering wheel 7), and a round-pipe-shaped exhaust pipe 10 extends downward from the right side of the exhaust purification device 9. A round-pipe-shaped first exhaust pipe 11 is connected to the exhaust pipe 10 and extends downward, and a round-pipe-shaped second exhaust pipe 12 is supported below the first exhaust pipe 11 in the up-down direction.

[0050] With the above configuration, the exhaust from the engine 4 is supplied from the exhaust purification device (not shown) (DPF) to the exhaust purification device 9 (SCR), and then sent from the exhaust pipe 10 to the first exhaust pipe 11, from the outlet 13 at the bottom of the first exhaust pipe 11 to the inlet 14 at the top of the second exhaust pipe 12, and then discharged from the outlet 15 at the bottom of the second exhaust pipe 12.

[0051] (Configuration of the cutout portion formed at the outlet of the first exhaust pipe) As shown in FIGS. 4 and 5, four triangular cutouts 18 are formed at the outer periphery of the outlet 13 of the first exhaust pipe 11 at 90 degree intervals.

[0052] In the outer periphery of the outlet 13 of the first exhaust pipe 11, two triangular cutouts 19 smaller than the cutouts 18 are formed in each of four portions between adjacent cutouts 18, for a total of eight cutouts 19. In this way, a plurality of cutouts 19 are formed all around the outer periphery of the outlet 13 of the first exhaust pipe 11.

[0053] The cutouts 18, 19 are formed point-symmetrically with respect to the center D1 of the outlet 13 of the first exhaust pipe 11 when viewed from the flow direction A1 of the exhaust exiting the outlet 13 of the first exhaust pipe 11 (see FIG. 2).

[0054] As shown in Figures 5 and 6, if we imagine imaginary straight lines E1, E2, E3, and E4 passing through the center D1 of the outlet 13 of the first exhaust pipe 11 when viewed from the direction A1 of the exhaust flow exiting from the outlet 13 of the first exhaust pipe 11 (see Figure 2), the cutout portion 19 is formed symmetrically with respect to the imaginary straight lines E1, E2, E3, and E4.

[0055] The cutout portions 18, 19 are formed to extend upward (to the opposite side to the second exhaust pipe 12) from the ends 13a, 13b of the outlet 13 of the first exhaust pipe 11. At the ends 13a, 13b of the outlet 13 of the first exhaust pipe 11, the end 13a adjacent to the cutout portion 18 extends downward (towards the second exhaust pipe 12) further than the end 13b between the cutout portions 19.

[0056] (Configuration of partition member provided at outlet of first exhaust pipe) 3, 4 and 5, partition members 16, 17 are formed by bending a plate material into a triangular cross section, and partition members 16, 17 are combined and connected to each other so that they are perpendicular to each other. Partition members 16, 17 are inserted into cutout portion 18 of outlet 13 of first exhaust pipe 11 and attached to outlet 13 of first exhaust pipe 11.

[0057] When viewed from the direction A1 (see FIG. 2 ) of the exhaust flow exiting the outlet 13 of the first exhaust pipe 11, the intersection of the partition members 16, 17 is disposed at the center of the outlet 13 of the first exhaust pipe 11. When viewed from the direction A1 of the exhaust flow exiting the outlet 13 of the first exhaust pipe 11, the partition members 16, 17 are disposed radially outward from the center of the outlet 13 of the first exhaust pipe 11.

[0058] The partition members 16, 17 are formed by bending a plate material into a triangular cross-section, so that when viewed from a direction (see FIG. 4) perpendicular to the direction A1 (see FIG. 2) of the exhaust flow exiting the outlet 13 of the first exhaust pipe 11, the cross-sectional shape of the partition members 16, 17 is formed into a wedge shape that tapers toward the upstream side of the exhaust flow exiting the outlet 13 of the first exhaust pipe 11.

[0059] The partition members 16, 17 are formed point-symmetrically with respect to the center D1 of the outlet 13 of the first exhaust pipe 11 when viewed from the flow direction A1 of the exhaust exiting the outlet 13 of the first exhaust pipe 11 (see FIG. 2).

[0060] As shown in Figures 5 and 6, if we imagine imaginary straight lines E1, E2, E3, and E4 passing through the center D1 of the outlet 13 of the first exhaust pipe 11 when viewed from the direction A1 of the exhaust flow exiting from the outlet 13 of the first exhaust pipe 11 (see Figure 2), the partition members 16 and 17 are formed symmetrically with respect to the imaginary straight lines E1, E2, E3, and E4. Even in the configuration in which the partition members 16, 17 and the cutout portion 19 are combined, the configuration in which the partition members 16, 17 and the cutout portion 19 are combined is formed line-symmetrically with respect to the imaginary straight lines E1, E2, E3, and E4.

[0061] Outer ends 16a, 17a of the partition members 16, 17 protrude radially outward from the outer periphery of the outlet 13 of the first exhaust pipe 11. Upper ends 16b, 17b of the partition members 16, 17 are located above the upper end 19a of the cutout portion 19 (opposite the second exhaust pipe 12) (see FIG. 4), and lower ends 16c, 17c of the partition members 16, 17 protrude downward (towards the second exhaust pipe 12) from the ends 13a, 13b of the outlet 13 of the first exhaust pipe 11 (see FIG. 4).

[0062] As a result, the partition members 16, 17 are attached to the first exhaust pipe 11 across a portion of the first exhaust pipe 11 that is farther away from the opposite end 19a of the second exhaust pipe 12 than the opposite end 19a of the second exhaust pipe 12 at the cutout portion 19 and the end 13a of the outlet 13 of the first exhaust pipe 11, and protrude from the ends 13a, 13b of the outlet 13 of the first exhaust pipe 11 towards the second exhaust pipe 12.

[0063] (Relationship between the partition member, the notch portion, and the outlet of the first exhaust pipe) 5 and 6, when viewed from the flow direction A1 (see FIG. 2) of the exhaust gas exiting the outlet 13 of the first exhaust pipe 11, the area of ​​the outlet 13 of the first exhaust pipe 11 is divided into four divided areas B1 by partition members 16, 17. The four divided areas B1 also include the area of ​​the cutout portion 19, and adjacent divided areas B1 are separated by the partition members 16, 17 with a gap C1, which is the width of the partition members 16, 17, between them. As a result, when viewed from the flow direction A1 (see FIG. 2) of the exhaust gas exiting the outlet 13 of the first exhaust pipe 11, the areas of the four divided regions B1 are the same.

[0064] When the exhaust gas from the engine 4 is sent to the first exhaust pipe 11, the exhaust gas from the engine 4 passes through the divided area B1 defined by the partition members 16, 17 at the outlet 13 of the first exhaust pipe 11 and is divided into four streams corresponding to the divided area B1. Immediately after the partition members 16, 17, the four streams of the exhaust gas from the engine 4 become independent streams, and then the four streams of the exhaust gas from the engine 4 are mixed with outside air and then merge together.

[0065] At the same time, because the cross-sectional shape of the partition members 16, 17 is formed into a wedge shape that tapers toward the upstream side of the exhaust flow issuing from the outlet 13 of the first exhaust pipe 11, the area of ​​the outlet 13 of the first exhaust pipe 11 is narrowed by the partition members 16, 17 and the flow of the exhaust of the engine 4 is obstructed by the partition members 16, 17, thereby increasing the flow speed of the four streams of the exhaust of the engine 4. A negative pressure space where the exhaust of the engine 4 does not flow is likely to be generated in the area downstream of the partition members 16, 17, and the negative pressure space described above tends to expand toward the downstream side.

[0066] In the flow corresponding to the divided region B1 of the exhaust of the engine 4, the boundary surface, which is the portion where the exhaust flow of the engine 4 comes into contact with the outside air, is the sum of a portion L1 corresponding to the lower end 16c of the partition member 16, a portion L2 corresponding to the lower end 17c of the partition member 17, two portions L3 corresponding to the outer periphery of the two cutout portions 19, and three portions L4 corresponding to the ends 13a, 13b of the outlet 13 of the first exhaust pipe 11. As a result, when the partition members 16 and 17 and the cutout portion 19 are provided, the boundary surface becomes the sum of the boundary surfaces of the four flows corresponding to the divided region B1 of the exhaust gas of the engine 4.

[0067] (Relationship between the first and second exhaust pipes) 3, the second exhaust pipe 12 is formed to have a larger diameter than the first exhaust pipe 11, and the inlet 14 of the second exhaust pipe 12 is formed to have a larger outer diameter than the outlet 13 of the first exhaust pipe 11. The outlet 15 of the second exhaust pipe 12 is formed to face laterally outward to the right from the fuselage 3.

[0068] As shown in FIG. 2, in a side view (a direction perpendicular to the direction A1 of the exhaust flow issuing from the outlet 13 of the first exhaust pipe 11), the outlet 13 of the first exhaust pipe 11 (the lower ends 16c, 17c of the partition members 16, 17) and the inlet 14 of the second exhaust pipe 12 are arranged close to each other so that a small gap C2 is between them.

[0069] As shown in FIG. 3, when viewed from the direction A1 (see FIG. 2) of the exhaust flow exiting from the outlet 13 of the first exhaust pipe 11, the outlet 13 of the first exhaust pipe 11 and the partition members 16, 17 are disposed inside the inlet 14 of the second exhaust pipe 12.

[0070] The outer periphery of the outlet 13 of the first exhaust pipe 11 and the outer periphery of the inlet 14 of the second exhaust pipe 12 are disposed with a distance C3 between them. The outer ends 16a, 17a of the partition members 16, 17 and the outer periphery of the inlet 14 of the second exhaust pipe 12 are disposed with a distance C4 narrower than the distance C3 between them.

[0071] With the above configuration, the exhaust from the engine 4 exits from the outlet 13 of the first exhaust pipe 11, is sent to the inlet 14 of the second exhaust pipe 12, enters the inside of the second exhaust pipe 12, and is discharged from the outlet 15 at the bottom of the second exhaust pipe 12.

[0072] As described above (Relationship between the partition member, the cutout portion, and the outlet of the first exhaust pipe), by providing the partition members 16, 17 and the cutout portion 19, the flow velocity of the exhaust gas from the engine 4 is appropriately increased. A negative pressure space where the exhaust gas from the engine 4 does not flow tends to be generated in the area downstream of the partition members 16, 17, and outside air tends to be mixed into this negative pressure space. The boundary surface when the partition members 16 and 17 and the cutout portion 19 are provided becomes the sum of the boundary surfaces of the four flows corresponding to the divided region B1 of the exhaust gas of the engine 4.

[0073] As a result, a large amount of outside air is drawn into the exhaust flow of engine 4, and is introduced into the interior of second exhaust pipe 12 from between the outer periphery of the outlet 13 of first exhaust pipe 11 and the outer periphery of the inlet 14 of second exhaust pipe 12, where it mixes with the exhaust of engine 4, lowering the temperature of the exhaust of engine 4.

[0074] (First Alternative Embodiment of the Invention) In the configurations shown in FIGS. 2 to 5, the cutout portion 19 may be eliminated. The outlet 13 of the first exhaust pipe 11 may be positioned slightly inside the inlet 14 of the second exhaust pipe 12 along the direction A1 (see Figure 2) of the exhaust flow exiting the outlet 13 of the first exhaust pipe 11 so that the outlet 13 of the first exhaust pipe 11 and the inlet 14 of the second exhaust pipe 12 overlap in a side view. The partition members 16,17 may be provided at the inlet 14 of the second exhaust pipe 12, and the outlet 13 of the first exhaust pipe 11 may be disposed adjacent to the partition members 16,17.

[0075] The partition members 16, 17 may be formed point-symmetrically with respect to the center D1 of the outlet 13 of the first exhaust pipe 11 when viewed from the direction A1 of the exhaust flow exiting the outlet 13 of the first exhaust pipe 11 (see FIG. 2), and the partition members 16, 17 may be configured to be combined and connected to each other at an angle other than 90 degrees so that the areas of the four divided regions B1 are not the same.

[0076] (Second Alternative Embodiment of the Invention) The cross-sectional shape of the partition members 16, 17 may be formed into a wedge shape that is half an elongated ellipse, instead of a triangular wedge shape. According to this configuration, the outer surfaces of the partition members 16, 17 are arc-shaped rather than linear in cross section, so that the flow of exhaust gas from the engine 4 along the outer surfaces of the partition members 16, 17 is expected to be smooth.

[0077] (Third Alternative Embodiment of the Invention) As shown in FIG. 7, the partition member 20 may be formed by constructing the partition member 20 from a flat plate-like member, and multiple arm portions 20a may be formed so as to extend radially outward from the center of the outlet 13 of the first exhaust pipe 11 from the center of the partition member 20.

[0078] In the configuration shown in Figure 7, the arm portion 20a of the partition member 20 is arranged point-symmetrically with respect to the center D1 of the outlet 13 of the first exhaust pipe 11 when viewed from the direction A1 (see Figure 2) of the exhaust flow exiting from the outlet 13 of the first exhaust pipe 11.

[0079] When imaginary straight lines E1 and E2 are assumed to pass through the center D1 of the outlet 13 of the first exhaust pipe 11 when viewed from the flow direction A1 (see FIG. 2) of the exhaust gas exiting the outlet 13 of the first exhaust pipe 11, the partition member 20 is formed to be line-symmetrical with respect to the imaginary straight lines E1 and E2. The imaginary straight line E1 can be assumed to pass through an arm portion 20a other than the arm portion 20a of the partition member 20 shown in FIG 7. The imaginary straight line E2 can be assumed to pass between the arm portions 20a other than the arm portions 20a of the partition member 20 shown in FIG 7.

[0080] One divided region B1 is formed by two adjacent arm portions 20a of the partition member 20 and the outer periphery of the outlet 13 of the first exhaust pipe 11. By setting the angle between the adjacent arm portions 20a of the partition member 20 to the same angle, the areas of the multiple divided regions B1 become the same.

[0081] In this case, the number of arm portions 20a of the partition member 20 may be three, four, five, or any other number. The angles between adjacent arm portions 20a of the partition member 20 may be set to be different from each other so that the areas of the multiple divided regions B1 are not the same. In addition to the partition member 20, a notch 19 shown in Figures 4 and 5 may be formed in the outlet 13 of the first exhaust pipe 11.

[0082] (Fourth Alternative Embodiment of the Invention) As shown in FIG. 8, the partition member 20 may be formed by forming a flat plate-like member with a plurality of circular openings 20b having the same inner diameter. One divided region B1 is formed by one opening 20b of the partition member 20. Since the openings 20b of the partition member 20 have the same inner diameter, the areas of the multiple divided regions B1 are the same.

[0083] In the configuration shown in Figure 8, the opening 20b of the partition member 20 is arranged point-symmetrically with respect to the center D1 of the outlet 13 of the first exhaust pipe 11 when viewed from the direction A1 (see Figure 2) of the flow of exhaust gas leaving the outlet 13 of the first exhaust pipe 11.

[0084] When imaginary straight lines E1 and E2 are assumed to pass through the center D1 of the outlet 13 of the first exhaust pipe 11 when viewed from the flow direction A1 (see FIG. 2) of the exhaust gas leaving the outlet 13 of the first exhaust pipe 11, the partition member 20 is formed to be line-symmetrical with respect to the imaginary straight lines E1 and E2. The imaginary straight line E1 can be assumed to pass through an inner opening 20b other than the inner opening 20b of the partition member 20 shown in FIG 8. The imaginary straight line E2 can be assumed to pass through an outer opening 20b other than the outer opening 20b of the partition member 20 shown in FIG 8. In this case, the openings 20b of the partition member 20 may be configured to have different inner diameters, so that the areas of the divided regions B1 are not the same as one another.

[0085] (Fifth Alternative Embodiment of the Invention) As shown in FIG. 9, the partition members 16, 17, and 20 may be eliminated, and a plurality of cutout portions 19 may be formed around the entire outer periphery of the outlet 13 of the first exhaust pipe 11. The plurality of cutouts 19 may not all be formed to the same size, but may be configured to include a mixture of cutouts 19 of different sizes, such as large cutouts 19 and small cutouts 19.

[0086] In the configuration shown in Figure 9, the cutout portion 19 is formed point-symmetrically with respect to the center D1 (see Figures 7 and 8) of the outlet 13 of the first exhaust pipe 11 when viewed from the direction A1 (see Figure 2) of the exhaust flow exiting the outlet 13 of the first exhaust pipe 11.

[0087] Assuming that there are imaginary straight lines E1, E2 passing through the center D1 of the outlet 13 of the first exhaust pipe 11 when viewed from the direction A1 of the exhaust flow exiting from the outlet 13 of the first exhaust pipe 11 (see Figure 2), the cutout portion 19 is formed symmetrically with respect to the imaginary straight lines E1, E2. The imaginary straight line E1 can be assumed to pass through an end portion on the second exhaust pipe 12 side of a cutout portion 19 different from the cutout portion 19 shown in Fig. 9. The imaginary straight line E2 can be assumed to pass through the center portion of a cutout portion 19 different from the cutout portion 19 shown in Fig. 9. The cutout portions 19 may be formed in various shapes, such as U-shape, rectangle, semicircle, etc., instead of triangular shapes, and cutout portions 19 of different shapes may be mixed. [Industrial Applicability]

[0088] The present invention can be applied not only to tractors, but also to agricultural work vehicles such as combine harvesters and riding rice transplanters, construction work vehicles such as backhoes and wheel loaders, and work vehicles for transporting materials, etc. [Explanation of symbols]

[0089] 4 Engine 11 First exhaust pipe 12 Second exhaust pipe 13 Exit 13a End 13b End 14 Entrance 16 Partition material 17 Partition material 19 Cutout 19a End 20 Partitioning material 20b opening A1 direction B1 split area C1 interval C2 Interval D1 center E1~E4 Virtual line

Claims

1. A first exhaust pipe to which engine exhaust is delivered; a second exhaust pipe having an inlet having an outer diameter larger than an outlet of the first exhaust pipe, an outlet of the first exhaust pipe and an inlet of the second exhaust pipe are disposed close to each other such that the outlet of the first exhaust pipe is disposed inside the inlet of the second exhaust pipe when viewed from a direction of exhaust flow exiting the outlet of the first exhaust pipe, a partition member is provided that divides an area of ​​the outlet of the first exhaust pipe into a plurality of divided areas as viewed from a flow direction of exhaust gas exiting the outlet of the first exhaust pipe and separates adjacent divided areas at intervals; A work vehicle in which, when viewed from a direction perpendicular to the direction of the exhaust flow exiting the outlet of the first exhaust pipe, the cross-sectional shape of the partition member is formed into a wedge shape that tapers toward the upstream side of the exhaust flow exiting the outlet of the first exhaust pipe.

2. 2. The work vehicle according to claim 1, wherein when viewed from a direction perpendicular to the direction of the exhaust flow exiting the outlet of the first exhaust pipe, a gap is provided between the outlet of the first exhaust pipe and the inlet of the second exhaust pipe.

3. 3. The work vehicle according to claim 1, wherein the partition member is attached to an outlet of the first exhaust pipe.

4. A work vehicle as described in any one of claims 1 to 3, wherein the partition member is formed so that the areas of the multiple divided regions are the same as each other when viewed from the direction of the exhaust flow exiting the outlet of the first exhaust pipe.

5. A work vehicle as described in any one of claims 1 to 4, wherein the partition members are formed so as to be radially disposed outward from the center of the outlet of the first exhaust pipe when viewed from the direction of the flow of exhaust gas leaving the outlet of the first exhaust pipe.

6. 5. The work vehicle according to claim 1, wherein the partition member is formed by opening a plurality of openings in a flat plate-like member.

7. A work vehicle according to any one of claims 1 to 6, wherein the partition member is formed symmetrically with respect to a virtual line passing through a center of the outlet of the first exhaust pipe when viewed from the direction of the flow of exhaust gas leaving the outlet of the first exhaust pipe.

8. A first exhaust pipe to which engine exhaust is delivered; a second exhaust pipe having an inlet having an outer diameter larger than an outlet of the first exhaust pipe, an outlet of the first exhaust pipe and an inlet of the second exhaust pipe are disposed close to each other such that the outlet of the first exhaust pipe is disposed inside the inlet of the second exhaust pipe when viewed from a direction of exhaust flow exiting the outlet of the first exhaust pipe, a partition member is provided that divides an area of ​​the outlet of the first exhaust pipe into a plurality of divided areas as viewed from a flow direction of exhaust gas exiting the outlet of the first exhaust pipe and separates adjacent divided areas at intervals; A work vehicle, wherein a notch is formed on an outer periphery of the outlet of the first exhaust pipe, the notch extending from an end of the outlet of the first exhaust pipe to an opposite side of the second exhaust pipe.

9. The partition member is the exhaust pipe is attached across a portion of the first exhaust pipe that is farther away from the second exhaust pipe than the end of the cutout portion on the opposite side of the second exhaust pipe and an outlet end of the first exhaust pipe; and 9. The work vehicle according to claim 8, wherein the first exhaust pipe protrudes from an end portion of an outlet of the first exhaust pipe toward the second exhaust pipe.

10. 10. A work vehicle as described in claim 8 or 9, wherein the partition member and the cutout portion are formed symmetrically with respect to a virtual line passing through a center of the outlet of the first exhaust pipe when viewed from the direction of the flow of exhaust gas exiting the outlet of the first exhaust pipe.

11. A work vehicle as described in any one of claims 8 to 10, wherein when viewed from a direction perpendicular to the direction of the exhaust flow exiting the outlet of the first exhaust pipe, the cross-sectional shape of the partition member is formed into a wedge shape that tapers toward the upstream side of the exhaust flow exiting the outlet of the first exhaust pipe.

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