JP2015021480A - Work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a work vehicle capable of easily securing mixing time required to mix exhaust gas and urea water in a urea water mixing pipe while being able to easily improve connection workability when connecting the urea water mixing pipe and an exhaust introduction pipe.SOLUTION: A work vehicle comprises: a traveling body 2 mounted with an engine 5; a first case 62 which removes particulate matters in exhaust gas of the engine 5; a second case 63 which removes nitrogen oxidized substances in the exhaust gas of the engine 5; a urea mixing pipe 73 which connects the first case 62 and the second case 63; and a urea water tank which supplies urea water to the urea mixing pipe 73. The work vehicle has a structure where the engine 5 is supported by the traveling body 2 in a manner that dampens vibration, the first case 62 and the urea mixing pipe 73 are fixed to an upper side of the engine 5 and an exhaust outlet pipe body 74 to be fixed to a side of the traveling body 2 is connected to an exhaust gas outlet side of the urea mixing pipe 73 through a flexible pipe 75.

Description

  The present invention relates to a work vehicle such as an agricultural machine (tractor, combine) or a construction machine (bulldozer, hydraulic excavator, loader) equipped with an engine, and more specifically, particulate matter (soot, contained in exhaust gas). The present invention relates to a work vehicle such as a tractor provided with an exhaust gas purifying device for removing particulate oxide or nitrogen oxides (NOx) contained in the exhaust gas.

  In a work vehicle such as a tractor or wheel loader, an opening / closing fulcrum shaft is arranged at the rear of the bonnet for covering the engine in order to improve the efficiency of maintenance work of the engine arranged at the front of the traveling machine body. The bonnet was rotated. Conventionally, a filter case having a diesel particulate filter and a catalyst case having a urea selective reduction catalyst are provided as exhaust gas purifiers (exhaust gas aftertreatment devices) in the exhaust path of a diesel engine. There has been known a technique for purifying exhaust gas discharged from a diesel engine by providing exhaust gas into a filter case and a catalyst case (see, for example, Patent Document 1 or 2).

JP 2009-74420 A US Patent Application Publication No. 2011/283687

  When the catalyst case is assembled with being separated from the engine as in Patent Document 2, an exhaust pipe for supplying exhaust gas from the engine to the catalyst case is formed by a support member that supports the catalyst case on the traveling machine body. In the structure, there is a problem that the support member needs to be formed in a special structure, and the manufacturing cost cannot be easily reduced. In addition, in the structure where the engine is supported by vibration isolation on the traveling aircraft body, when the exhaust pipe or the catalyst case is assembled on the traveling aircraft body side, it is necessary to provide vibration isolation support for the exhaust pipe or the catalyst case. There is also a problem that the mounting structure cannot be easily simplified.

  Therefore, the present invention seeks to provide a work vehicle that has been improved by examining these current conditions.

  In order to achieve the object, a work vehicle according to a first aspect of the present invention includes a traveling machine body on which an engine is mounted, a first case for removing particulate matter in exhaust gas from the engine, and exhaust gas from the engine. In a work vehicle comprising: a second case for removing nitrogen oxides; a urea mixing pipe connecting the second case to the first case; and a urea water tank for supplying urea water to the urea mixing pipe. And a structure for supporting the engine in an anti-vibration manner, wherein the first case and the urea mixing pipe are fixed to the upper position of the engine and the exhaust lead-out pipe fixed to the traveling machine body side, and the urea mixing The exhaust gas outlet side of the pipe is connected by a flexible pipe.

  According to a second aspect of the present invention, in the work vehicle according to the first aspect, the first case and the urea mixing pipe are disposed on the engine side, and the second case is disposed on the traveling machine body side. A flexible pipe is connected between the exhaust gas outlet of the urea mixing pipe and the exhaust gas inlet of the second case.

  According to a third aspect of the present invention, in the work vehicle according to the first aspect, a heat insulating cover body that covers the flexible pipe is provided, and the flexible pipe is disposed below a rear portion of a hood that covers the engine.

  According to a fourth aspect of the present invention, the work vehicle according to the first aspect includes a urea water tank for exhaust gas purification and a urea mixing pipe for supplying urea water from the urea water tank. The exhaust inlet side of the second case is connected to the exhaust outlet side via the urea mixing pipe, and the engine output shaft core and the exhaust gas moving direction of the first case are parallel to each other. A first case is supported, the exhaust gas outlet side of the first case is extended toward one end of the output shaft of the engine, and the urea mixing pipe is connected in parallel with the exhaust gas movement direction of the first case. The exhaust gas outlet side of the urea mixing pipe is extended toward the other end side of the output shaft of the engine.

  According to the first aspect of the present invention, the traveling machine body on which the engine is mounted, the first case for removing the particulate matter in the exhaust gas of the engine, and the first for removing the nitrogen oxide substance in the exhaust gas of the engine. In a work vehicle including two cases, a urea mixing pipe connecting the second case to the first case, and a urea water tank for supplying urea water to the urea mixing pipe, the engine is supported on the traveling body in a vibration-proof manner. The exhaust gas outlet pipe body fixed to the traveling machine body side and the exhaust gas outlet side of the urea mixing pipe are fixed to the first case and the urea mixing pipe at the upper position of the engine. Since the flexible pipe is connected, vibrations of the engine can be absorbed by the flexible pipe, so that the first case and the urea mixture are disposed on the upper surface side of the engine. The pipe can be easily fixed, and errors in the assembly dimensions of the urea mixing pipe or the exhaust lead-out pipe body can be absorbed by the flexible pipe, so that the urea mixing pipe and the exhaust lead-out pipe body are connected. Workability can be easily improved. Further, the urea mixing pipe can be elongated on the outer peripheral side of the engine, and the mixing time of the exhaust gas and urea water required for the urea mixing pipe can be easily secured and the assembly workability of the urea mixing pipe can be secured. Etc. can be improved easily.

  According to the second aspect of the present invention, the first case and the urea mixing pipe are disposed on the engine side, and the second case is disposed on the traveling machine body side, and the exhaust gas of the urea mixing pipe is disposed. Since the flexible pipe is connected between the outlet and the exhaust gas inlet of the second case, the second case can be easily fixed to the traveling machine body, and the urea mixing pipe on the engine side and the traveling Errors in assembly dimensions with the second case (the exhaust lead-out pipe body) on the machine body side can be absorbed by the flexible pipe, and the connection workability between the urea mixing pipe and the second case can be easily achieved. It can be improved.

  According to invention of Claim 3, while providing the heat insulation cover body which covers the said flexible pipe, the said flexible pipe is arrange | positioned under the rear part of the bonnet which covers the said engine, In the said heat insulation cover body, the said It is possible to easily suppress the temperature of the exhaust gas in the flexible pipe from being lowered, and to improve the detachability of the heat insulating cover body or the flexible pipe.

  According to a fourth aspect of the present invention, a urea water tank for purifying exhaust gas and a urea mixing pipe for supplying urea water from the urea water tank are provided, and the urea mixing pipe is provided on the exhaust outlet side of the first case. The exhaust case side of the second case is connected via the first case, the first case is supported in a posture in which the output shaft core line of the engine and the exhaust gas movement direction of the first case are parallel, The exhaust gas outlet side of the first case is extended toward one end side of the engine output shaft, and the urea mixing pipe is supported in parallel with the exhaust gas movement direction of the first case, so that the engine output shaft Since the exhaust gas outlet side of the urea mixing tube is extended toward the other end of the urea, the urea mixing tube is heated by the heat generated on the engine or the first case side, and the urea mixing Crystal of urea water in the tube And the length of the urea mixing tube heating section heated by the heat generated by the engine can be made longer than the length necessary for mixing urea water as ammonia into the exhaust gas. The exhaust gas hatching function for removing nitrogen oxides in the exhaust gas in the second case can be improved.

It is a perspective view of the tractor which shows 1st Embodiment. It is the same top view. It is a top view of an engine part. It is a right view of the same part. It is a left view of the same part. It is a right view of the 2nd case attachment structure. It is a right view which shows the modification of a 2nd case attachment structure. It is a right view which shows the modification of a 2nd case attachment structure.

  Below, 1st Embodiment which actualized this invention is described based on drawing (FIGS. 1-6). First, a farm tractor 1 equipped with a diesel engine will be described with reference to FIGS. A farm tractor 1 as a work vehicle shown in FIGS. 1 and 2 is configured to perform a plowing work and the like for plowing a farm field by mounting a plow working machine (not shown). FIG. 1 is a perspective view of the tractor 1, and FIG. 2 is a plan view thereof. In the following description, the left side in the forward direction of the tractor 1 is simply referred to as the left side, and the right side in the forward direction is also simply referred to as the right side.

  As shown in FIGS. 1 and 2, a farm tractor 1 as a work vehicle supports a traveling machine body 2 with a pair of left and right front wheels 3 and a pair of left and right rear wheels 4, and a diesel engine at the front of the traveling machine body 2. 5 and driving the rear wheel 4 and the front wheel 3 with the diesel engine 5, the vehicle is configured to travel forward and backward. The upper surface side and the left and right side surfaces of the diesel engine 5 are covered with an openable / closable bonnet 6.

  In addition, on the upper surface of the traveling machine body 2, behind the hood 6, a driving cabin 7 is installed as a driving unit on which an operator gets on. Inside the cabin 7 is provided a front column 10 including a control seat 8 on which an operator sits, a control handle 9 as steering means, and the like. A fuel tank 12 that supplies fuel to the diesel engine 5 is provided below the boarding step 11 at the bottom of the cabin 7. In the front column 10, left and right brake pedals 13, a clutch pedal 14, a transmission pedal 15, a forward / reverse switching lever 16 and the like are disposed as steering devices.

  The traveling machine body 2 also includes a mission case 17 for shifting the output from the diesel engine 5 and transmitting it to the rear wheels 4 (front wheels 3). The rear of the mission case 17 is connected to a tiller mechanism (not shown) and the like via a traction mechanism 21 such as a left and right lower link 18, a top link 19, and a left and right lift arm 20, and the like. The plowing machine and the like are driven by a PTO shaft (not shown) provided on the rear side surface of 17. Furthermore, the traveling machine body 2 of the tractor 1 includes a diesel engine 5, a transmission case 17, a clutch case 22 that connects them, a front chassis 23 that extends forward from the diesel engine 5, and the like. In addition, a pair of left and right boarding steps 24 for the operator to get on and off are arranged on the left and right outer portions of the cabin 7.

  Next, the diesel engine 5 will be described with reference to FIGS. As shown in FIGS. 3 to 5, an intake manifold 33 is disposed on one side surface of the cylinder head 32 of the diesel engine 5. The cylinder head 32 is mounted on a cylinder block 35 in which an engine output shaft (crank shaft) and a piston (not shown) are incorporated. An exhaust manifold 36 is disposed on the other side of the cylinder head 32, and the front end and the rear end of the engine output shaft are projected from the front and rear surfaces of the cylinder block 35.

  As shown in FIGS. 3 to 5, a flywheel housing 38 is fixed to the rear surface of the cylinder block 35. A flywheel (not shown) is provided in the flywheel housing 38. The front side of the clutch case 22 is connected to the rear side of the flywheel housing 38. The power of the diesel engine 5 is extracted from the rear end side of the engine output shaft on which the flywheel is pivoted toward the transmission case 17. Further, an oil pan 39 is disposed on the lower surface of the cylinder block 35, a cooling fan 40 is disposed on the front surface side of the cylinder block 35, and a radiator 41 is installed facing the cooling fan 40. An oil cooler 42, an air cleaner 43, a battery 44, and the like are disposed on the front chassis 23 in front of the radiator 41.

  As shown in FIGS. 3 to 5, an exhaust gas recirculation device (EGR) 45 that takes in exhaust gas for recirculation is disposed in the intake manifold 33. An air cleaner 43 shown in FIG. 4 is connected to the intake manifold 33. The external air that has been dedusted and purified by the air cleaner 43 is sent to the intake manifold 33 and supplied to each cylinder of the diesel engine 5.

  With the above configuration, a part of the exhaust gas discharged from the diesel engine 5 to the exhaust manifold 36 is recirculated from the intake manifold 33 to each cylinder of the diesel engine 5 via the exhaust gas recirculation device 45. The combustion temperature of the diesel engine 5 is lowered, the amount of nitrogen oxide (NOx) discharged from the diesel engine 5 is reduced, and the fuel efficiency of the diesel engine 5 is improved.

  A cooling water pump 46 that circulates cooling water in the cylinder block 35 and the radiator 41 is provided. A cooling water pump 46 is arranged on the cooling fan 40 installation side on the front side of the diesel engine 5. The cooling water pump 46 and the cooling fan 40 are connected to the engine output shaft of the diesel engine 5 via a V belt or the like, and the cooling water pump 46 and the cooling fan 40 are driven. While the cooling water is fed from the cooling water pump 46 into the cylinder block 35 via the EGR cooler 47 of the exhaust gas recirculation device 45, the diesel engine 5 is cooled by the cooling fan 40 wind. .

  As shown in FIG. 4, each of the injectors 51 for four cylinders of the diesel engine 5 is provided with a fuel pump 52 and a common rail 53 that connect the fuel tank 12 shown in FIG. A common rail 53 and a fuel filter 54 are arranged on the intake manifold 33 installation side of the cylinder head 32, and a fuel pump 52 is arranged in the cylinder block 35 below the intake manifold 33. Each injector 51 has an electromagnetic switching control type fuel injection valve (not shown).

  While the fuel in the fuel tank 12 is sucked into the fuel pump 52 via the fuel filter 54, the common rail 53 is connected to the discharge side of the fuel pump 52, and the cylindrical common rail 53 is connected to each injector 51 of the diesel engine 5. It is connected. The surplus of the fuel pumped from the fuel pump 52 to the common rail 53 is returned to the fuel tank 12, high-pressure fuel is temporarily stored in the common rail 53, and the high-pressure fuel in the common rail 53 is used for each diesel engine 5. Supplied inside the cylinder.

  With the above configuration, the fuel in the fuel tank 12 is pumped to the common rail 53 by the fuel pump 52, the high-pressure fuel is stored in the common rail 53, and the fuel injection valves of the injectors 51 are controlled to open and close. High-pressure fuel in the common rail 53 is injected into each cylinder of the diesel engine 5. That is, by electronically controlling the fuel injection valve of each injector 51, the fuel injection pressure, injection timing, and injection period (injection amount) can be controlled with high accuracy. Therefore, nitrogen oxides (NOx) discharged from the diesel engine 5 can be reduced.

  As shown in FIG. 3 to FIG. 6, as an exhaust gas purification device 61 for purifying exhaust gas discharged from each cylinder of the diesel engine 5, a diesel party that removes particulate matter in the exhaust gas of the diesel engine 5 is used. A first case 62 as a curate filter (DPF) and a second case 63 as a urea selective catalytic reduction (SCR) system for removing nitrogen oxides in exhaust gas of the diesel engine 1 are provided. As shown in FIG. 3, an oxidation catalyst 64 and a soot filter 65 are provided in the first case 62. The second case 63 includes an SCR catalyst 66 and an oxidation catalyst 67 for reducing urea selective catalyst.

  Exhaust gas discharged from each cylinder of the diesel engine 5 to the exhaust manifold 36 is discharged to the outside via the exhaust gas purification device 61 and the like. The exhaust gas purification device 61 is configured to reduce carbon monoxide (CO), hydrocarbons (HC), particulate matter (PM), and nitrogen oxides (NOx) in the exhaust gas of the diesel engine 5. doing.

  The first case 62 is configured in a horizontally long long cylindrical shape extending long in a direction parallel to the output shaft (crankshaft) of the diesel engine 5 in plan view. A DPF inlet pipe 68 for taking in exhaust gas is provided on one end of the first case 62 in the cylindrical shape. Of the front and rear surfaces of the diesel engine 5, the one end side and the other end side of the first case 62 in the exhaust gas movement direction can be attached to and detached from the front and rear surfaces of the cylinder head 32 via the front support leg body 69 and the rear support leg body 70. I support it. That is, the first case 62 is attached to the upper surface side of the diesel engine 5 through the front support leg 69 and the rear support leg 70. The first case 62 is supported in parallel with the exhaust manifold 36 with the longitudinal direction of the cylindrical first case 62 facing the longitudinal direction of the diesel engine 5.

  A supercharger 71 for forcibly sending air to the diesel engine 5 is disposed at the exhaust gas outlet of the exhaust manifold 36. The DPF inlet pipe 68 is communicated with the exhaust manifold 36 via the supercharger 71, and the exhaust gas of the diesel engine 5 is introduced into the first case 62 from the DPF inlet pipe 68. On the other hand, a DPF outlet pipe 72 for exhaust gas exhaust is provided on the other end side of the cylindrical shape of the first case 62. The DPF outlet pipe 72 of the first case 62 is connected to the inlet side of the urea mixing pipe 73, and the exhaust gas of the first case 28 is introduced into the urea mixing pipe 73.

  On the other hand, the 2nd case 63 is comprised in the horizontally long elongate cylindrical shape extended long in the left-right direction. An SCR inlet pipe 74 for taking in exhaust gas is provided at the left end of the cylindrical shape of the second case 63. An SCR inlet pipe 74 is connected to the outlet side of the urea mixing pipe 73 through a bellows-like connecting pipe 75 that can be bent and stretched. Furthermore, the end of the urea mixing pipe 73 to which the bellows-like connecting pipe 75 is connected is detachably fixed to the side surface of the cylinder block 35 with a pipe bracket 76.

  Further, the DPF inlet pipe 68 is located on the rear side of the diesel engine 5, the exhaust gas flows from the rear part to the front part of the first case 62, and the urea mixing pipe provided in parallel with the first case 62 at the upper part of the diesel engine 5. The exhaust gas moves to 73. That is, the urea mixing pipe 73 extending in the front-rear direction is fixed to the upper surface side of the diesel engine 5 via the first case 62 and the pipe bracket 76, and the first case 62 side of the upper surface of the diesel engine 5 is fixed. On the other hand, the urea mixing pipe 73 is arranged in parallel with the first case 62, and the first case 62 and the urea mixing pipe 73 can be integrally fixed to the diesel engine 5 supported by vibration isolation. The mechanical vibration on the urea mixing pipe 73 side is blocked by the bellows-like connecting pipe 75 and is not transmitted to the SCR inlet pipe 74 side.

  Further, as shown in FIG. 6, the lower end side of the tail pipe 81 is connected to the cylindrical right end portion of the second case 63. The tail pipe 81 is erected substantially vertically along the cabin frame 82 at the right corner of the operation cabin 7. The tail pipe 81 and the pipe cover 84 are fixed to the cabin frame 82 via the pipe mounting bracket 83. On the other hand, the base end side of the left and right step frame 86 as a traveling machine body frame is bolted to the left and right side surfaces of the clutch case 22 via the board bracket 85, and the left and right step frames are directed toward the left and right outer sides of the clutch case 22. The front end side of 86 is horizontally extended, and the operation cabin 7 is attached to the upper surface side of the middle part of the left and right step frames 86 via the cabin fixing shaft body 87, and the getting-on / off step 24 and the like are attached to the front end parts of the left and right step frames 86. .

  Further, as shown in FIG. 6, the step frame 86 supports the second case 63, a column member 120 is welded and fixed to the lower surface side of the step frame 86, and a pair of left and right cases are mounted on the front side of the column member 120. The support plate 121 is fixed by welding, the case support plate 121 is integrally fixed to the step frame 86, and a pair of left and right case support plates 121 are projected from the support member 120 toward the front. A case support bracket 122 is integrally welded and fixed to the back side of the second case 63 out of the outer peripheral surface of the second case 63 for purifying exhaust gas, and the case support bracket 122 is moved rearward from the second case 63. Make it project. The case support bracket 122 is fitted between the pair of left and right case support plate bodies 121, and the upper bolt 126a and the lower bolt 126b are screwed to the left and right side surfaces of the pair of left and right case support plate bodies 121 and the case support bracket 122 from the left and right directions. The case support bracket 122 is fastened to the case support plate 121, and the second case 63 is detachably fixed to the step frame 86.

  Further, the upper bolt 126a is removably engaged with the engagement opening 121a having a forward opening shape of the case support plate 121, and the lower bolt 126b is passed through the position adjusting long hole 121b of the case support plate 121. That is, when the second case 63 is assembled, first, the upper bolt 126a is temporarily fixed to the case support bracket 122, the second case 63 is brought close to the mounting position of the case support plate 121, and the case support plate 121 is attached. The upper bolt 126a is engaged with the engagement notch 121a, and the second case 63 is temporarily fixedly supported by the case support plate 121. Thereafter, the lower bolt 126b is passed through the position adjusting long hole 121b of the case support plate 121, the lower bolt 126b is fastened to the case support bracket 122, and the upper bolt 126a is also fastened to the case support bracket 122. 126b, the case support bracket 122 is detachably fixed to the case support plate 121, and the second case 63 is mounted on the front side of the driving cabin 7 (driving unit) via the step frame 86. Yes. Accordingly, the first case 28 is arranged on the upper surface side of the diesel engine 1 in a horizontally long horizontal posture facing in the front-rear direction, while the second case 63 in a horizontally long posture facing in the left-right direction on the right side of the rear portion of the diesel engine 1. Is placed.

  Further, as shown in FIGS. 4 and 5, a urea water tank 91 is mounted on the traveling machine body 2 (front chassis 23) at the front of the bonnet 6. An oil injection port 92 for the fuel tank 12 is provided in the lower front portion on the left side of the cabin 7, and a water injection port 93 for the urea water tank 91 is provided on the left side of the front portion of the bonnet 6. An oil injection port 92 and a water injection port 93 are arranged on the left side of the traveling machine body 2 where the frequency of getting on and off by the operator is high, and a urea water tank 91 is arranged between the left and right front chassis 23 via a tank support frame 90. On the upper surface side of the front chassis 23, the oil cooler 42, the air cleaner 43, and the battery 44 are respectively disposed above the urea water tank 91 (in the engine room 89 formed by the bonnet 6).

  In addition, a radiator 41 is disposed between the cooling fan 40 and the oil cooler 42 on the front surface side of the diesel engine 5 in the upper surface side of the front chassis 23, and the diesel engine in the engine room 89 formed by the bonnet 6. 5. A urea mixing pipe 73 is extended and supported in the front-rear direction on the upper surface side (the right side of the second case where the exhaust gas moves from the rear to the front).

  Further, a urea water injection pump 94 that pumps the urea aqueous solution in the urea water tank 91, an electric motor 95 that drives the urea water injection pump 94, and urea that is connected to the urea water injection pump 94 via a urea water injection pipe 96. A water injection nozzle 97 is provided. A urea water injection pump 94 and an electric motor 95 are provided on the rear surface side of the urea water tank 91, the middle of the urea water injection pipe 96 is covered with a heat insulating pipe cover body 96 a, the right side surface of the shroud 47, and the radiator 41. A pipe cover body 96 a is fixedly supported on the right side of the radiator 41 via a pipe stopper 48, and a urea water injection pipe 96 is piped from the right side surface of the radiator 41 toward the urea mixing pipe 73. The shroud 47 is disposed on the rear surface side of the radiator 41, covers the outside of the cooling fan 40 with the shroud 47, and moves the cooling fan 40 wind from the radiator 41 toward the outer periphery of the diesel engine 5.

  Further, a urea water injection nozzle 97 is attached to the front end portion of the urea mixing pipe 73 connected to the front surface side of the first case 62 via the injection base 98. One end side of the urea water injection pipe 96 is connected to the urea water injection pump 94, the other end side of the urea water injection pipe 96 is connected to the urea water injection nozzle 97, and the urea water injection nozzle 97 is connected to the inside of the urea mixing pipe 73. The urea aqueous solution in the urea water tank 91 is sprayed. The urea water supplied into the urea mixing pipe 73 is configured to be mixed as ammonia in the exhaust gas from the first case 62 to the second case 63.

  In addition, as shown in FIGS. 3 and 6, a heat insulating cover body 99 (or a heat-resistant heat insulating material such as glass fiber) covering the bellows-like connecting pipe 75 is provided, and a heat insulating cover is provided on the outer peripheral side of the bellows-like connecting pipe 75. The body 99 is wound, and the heat insulating cover body 99 prevents the exhaust gas temperature in the bellows-like connecting pipe 75 from decreasing, and the crystallization of urea in the exhaust gas in the bellows-like connecting pipe 75 is suppressed. Yes. The urea mixing pipe 73 has an elbow pipe part that changes the movement direction of the exhaust gas by about 90 degrees and a long cylindrical straight pipe part that is connected to the SCR inlet pipe 74. An injection pedestal 98 is fixed by welding to an elbow pipe part near the elbow pipe part and the straight pipe part, and a urea aqueous solution is supplied from the urea water injection nozzle 97 toward the inner hole of the straight pipe part from the elbow pipe part side. It sprays and ammonia is produced | generated by hydrolysis of the urea aqueous solution, and the ammonia is mixed in the exhaust gas in the straight pipe part.

  With the above configuration, the oxidation catalyst 64 and the soot filter 65 in the first case 62 reduce carbon monoxide (CO) and hydrocarbons (HC) in the exhaust gas of the diesel engine 5. Next, urea water from the urea water injection nozzle 97 is mixed into the exhaust gas from the diesel engine 5 inside the urea mixing pipe 73. The SCR catalyst 66 and the oxidation catalyst 67 in the second case 63 reduce nitrogen oxides (NOx) in the exhaust gas in which urea water is mixed as ammonia. That is, exhaust gas with reduced carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) is discharged from the tail pipe 81 to the outside of the machine.

  As shown in FIGS. 1 to 6, a traveling machine body 2 on which a diesel engine 5 is mounted, a first case 62 for removing particulate matter in exhaust gas of the engine 5, and nitrogen oxides in exhaust gas of the diesel engine 5. In the work vehicle including the second case 63 for removing the vehicle, the step frame 86 on the lower surface side of the driving cabin 7 on one side of the traveling vehicle body 2 among the lower surface side of the driving cabin 7 as the driving portion installed in the traveling vehicle body 2. A case support plate 121 as a case support and a case support bracket 122 are arranged, and a second case 63 is attached to the lower surface side of the operation cabin 7 in a horizontally long posture via the case support plate 121 and the case support bracket 122. Yes. Therefore, the case support plate 121 can be installed on the highly rigid step frame 86, and the manufacturing cost can be easily reduced by simplifying the size of the case support plate 121 and the case support bracket 122, and the second case 63 can be supported. The rigidity and the like can be easily improved, and the assembly workability of the second case 63 can be easily improved.

  As shown in FIGS. 3 to 6, a second case 63 having a horizontally long posture is attached along the front end side of the boarding step 11 on the lower surface side of the operation cabin 7 via the case support plate 121 and the case support bracket 122. Yes. Therefore, the second case 63 can be compactly installed while ensuring the front view of the operator of the driving cabin 7. Further, the second case 63 support structure can be easily simplified as compared with a conventional structure that also supports the second case 63 using the exhaust pipe.

  As shown in FIGS. 3 to 5, a urea water tank 91 for purifying exhaust gas and a urea mixing pipe 73 for supplying urea water from the urea water tank 91 are provided, and the urea mixing pipe 73 is provided at the exhaust outlet of the first case 62. The exhaust gas inlet of the second case 63 is connected to the upper surface of the diesel engine 5 so that the first case 62 is supported, and the urea mixing pipe is parallel to the exhaust gas movement direction of the first case 62. 73 is extended. Accordingly, the long urea mixing pipe 73 necessary for mixing urea water can be compactly arranged on the upper surface of the diesel engine 5, and the urea mixing pipe 73 is heated by the heat generated on the diesel engine 5 side. Even in this operation, the temperature of the exhaust gas or urea aqueous solution in the urea mixing pipe 73 can be easily maintained, and the crystallization of urea water in the urea mixing pipe 73 can be reduced.

  As shown in FIGS. 3 to 5, the front chassis 23 as the left and right engine frames is extended forward from the diesel engine 5, and the radiator 41 or the front wheel 3 is disposed on the left and right front chassis 23. A urea water tank 91 is attached between the left and right front chassis 23. Therefore, the urea water tank 91 can be easily assembled using the space between the left and right front chassis 23, and the urea water tank 91 can be made compact inside the hood 6 (engine room 89) for covering the diesel engine 5. Can be placed.

  As shown in FIGS. 1 to 4 and 6, the traveling machine body 2 on which the diesel engine 5 is mounted, the first case 62 for removing particulate matter in the exhaust gas of the diesel engine 5, and the exhaust gas of the diesel engine 5 In a work vehicle comprising a second case 63 for removing nitrogen oxides, a urea mixing pipe 73 connecting the second case 63 to the first case 62, and a urea water tank 91 for supplying urea water to the urea mixing pipe 73 The diesel engine 5 is vibration-proofed and supported on the traveling machine body 2, and the first case 62 and the urea mixing pipe 73 are fixed to the upper position of the diesel engine 5 and the exhaust lead-out pipe is fixed to the traveling machine body 2 side. The SCR inlet pipe 74 as a body and the exhaust gas outlet side of the urea mixing pipe 73 are connected by a bellows-like connecting pipe 75 as a flexible pipe. Since the vibration of the engine 5 can be absorbed by the flexible pipe 75, the first case 62 and the urea mixing pipe 73 can be easily fixed to the upper surface side of the diesel engine 5, and the urea mixing pipe 73 or the SCR inlet pipe Since errors in assembly dimensions such as 74 can be absorbed by the bellows-like connecting pipe 75, the connection workability of the urea mixing pipe 73 and the SCR inlet pipe 74 can be easily improved. Further, the urea mixing pipe 73 can be extended to the outer periphery side of the diesel engine 5 so that the mixing time of the exhaust gas and urea water necessary for the urea mixing pipe 73 can be easily secured and the urea mixing pipe 73 is assembled. Workability can be easily improved.

  As shown in FIGS. 3, 4, and 6, the first case 62 and the urea mixing pipe 73 are disposed on the diesel engine 5 side, and the second case 63 is disposed on the traveling machine body 2 side. Since the bellows-like connecting pipe 75 is connected between the exhaust gas outlet and the exhaust gas inlet of the second case 63, the second case 63 can be easily fixed to the traveling machine body 2 side, and urea on the diesel engine 5 side can be secured. The assembly size error between the mixing pipe 73 and the second case 63 (SCR inlet pipe 74) on the traveling machine body 2 side can be absorbed by the bellows-like connecting pipe 75, and the urea mixing pipe 73 and the second case 63 are absorbed. It is possible to easily improve the connection workability.

  As shown in FIGS. 3, 4, and 6, a heat insulating cover body 99 that covers the bellows-like connecting pipe 75 is provided, and the bellows-like connecting pipe 75 is arranged below the rear part of the bonnet 6 that covers the diesel engine 5. In addition, it is possible to easily suppress the temperature of the exhaust gas in the bellows-like connecting pipe 75 from being lowered by the heat insulating cover body 99, and to improve the attaching / detaching workability of the heat insulating cover body 99 or the bellows-like connecting pipe 75.

  As shown in FIGS. 3 to 6, a urea water tank 91 for purifying exhaust gas and a urea mixing pipe 73 for supplying urea water from the urea water tank 91 are provided, and urea mixing 73 is provided on the exhaust outlet side of the first case 62. The first case 62 is supported in a posture in which the output shaft core line of the diesel engine 5 and the exhaust gas movement direction of the first case 62 are parallel to each other. The exhaust gas outlet side of the first case 62 is extended toward one end side of the output shaft of the engine 5 (the front part of the diesel engine 5 in which the cooling fan 40 is disposed) and parallel to the exhaust gas movement direction of the first case 62. The urea mixing pipe 73 is supported by the exhaust pipe 73, and the urea mixing pipe 73 is exhausted toward the other end of the output shaft of the diesel engine 5 (the rear part of the diesel engine 5 in which the flywheel housing 38 is disposed). Since the exhaust outlet side is extended, the urea mixing pipe 73 is heated by the heat generated on the diesel engine 5 or the first case 62 side, and the crystallization of urea water in the urea mixing pipe 73 can be reduced. At the same time, the heating part of the urea mixing pipe 73 (elbow pipe part and straight pipe part) heated by the heat generated by the diesel engine 5 to a length necessary for mixing the urea water as ammonia into the exhaust gas or longer. ) Can be formed long, and the exhaust gas hatching function for removing nitrogen oxides in the exhaust gas in the second case 63 can be improved.

  Next, a modification of the mounting structure of the second case 63 will be described with reference to FIG. As shown in FIG. 7, the second frame 63 is supported by the step frame 86, a column member 120 is welded and fixed to the front side of the step frame 86, and a pair of left and right case support plates is mounted on the front side of the column member 120. The body 121 is fixed by welding, the case support plate 121 is integrally fixed to the step frame 86, and a pair of left and right case support plates 121 are projected from the support member 120 toward the front. A case support bracket 122 is integrally welded and fixed to the lower surface side of the second case 63 in the outer peripheral surface of the second case 63 for purifying exhaust gas, and the case support bracket 122 is directed downward from the second case 63. Make it project. The case support bracket 122 is fitted between the pair of left and right case support plate bodies 121, and the upper bolt 126a and the lower bolt 126b are screwed to the left and right side surfaces of the pair of left and right case support plate bodies 121 and the case support bracket 122 from the left and right directions. The case support bracket 122 is fastened to the case support plate 121, and the second case 63 is detachably fixed to the step frame 86.

  In addition, the upper bolt 126a is removably engaged with the engagement notch 121a having an upward opening shape in the case support plate 121, and the lower bolt 126b is passed through the position adjusting long hole 121b of the case support plate 121. That is, when assembling the second case 63, as in the first embodiment, the case support bracket 122 is detachably fixed to the case support plate 121 via the bolts 126a and 126b, and the step frame 86 is used. The second case 63 is mounted on the front side of the driving cabin 7 (driving unit). Therefore, the second case 63 can be supported at a higher position than in the first embodiment.

  Next, a modification of the mounting structure of the second case 63 will be described with reference to FIG. As shown in FIG. 8, the second case 63 is supported by the step frame 86, a support member 120 is welded and fixed to the front side of the step frame 86, and a pair of left and right case support plates is provided on the rear surface side of the support member 120. The body 121 is fixed by welding, the case support plate 121 is integrally fixed to the step frame 86, and a pair of left and right case support plates 121 are projected from the support member 120 toward the rear. A case support bracket 122 is integrally welded and fixed to the front surface side of the second case 63 out of the outer peripheral surface of the second case 63 for purifying exhaust gas, and the case support bracket 122 is moved forward from the second case 63. Make it project. The case support bracket 122 is fitted between the pair of left and right case support plate bodies 121, and the upper bolt 126a and the lower bolt 126b are screwed to the left and right side surfaces of the pair of left and right case support plate bodies 121 and the case support bracket 122 from the left and right directions. The case support bracket 122 is fastened to the case support plate 121, and the second case 63 is detachably fixed to the step frame 86.

  Further, the upper bolt 126 a is removably locked to the engagement notch 121 a having a rearward opening shape of the case support plate 121, and the lower bolt 126 b is passed through the position adjusting long hole 121 b of the case support plate 121. That is, when assembling the second case 63, the case support bracket 122 is detachably fixed to the case support plate 121 via the bolts 126a and 126b, and the lower surface side of the step frame 86, as in the first embodiment. The second case 63 is attached to the. Therefore, the second case 63 can be supported between the right side surface of the clutch case 22 and the inner surface side of the right getting on / off step 24. In the third embodiment, the second case 63 is supported in a horizontally long posture so that the exhaust gas movement direction of the second case 63 is left and right, but the exhaust gas movement direction of the second case 63 is It is also possible to support the second case 63 in a posture that is horizontally long in the front-rear direction so that the second case 63 and the tail pipe 81 extend rearward on the lower surface side of the boarding step 11.

  As shown in FIG. 8, the lower side of the driving cabin 7 is below the boarding step 11 and between the one side surface of the traveling machine body 2 and the boarding / exiting step 24 via the case support plate 121 and the case support bracket 122. Two cases 63 are attached. Accordingly, the outside of the second case 63 can be protected at the getting-on / off step 24, and the space between the side surface of the traveling machine body 2 and the getting-on / off step 24 can be utilized in a compact manner.

2 traveling machine body 5 diesel engine 6 bonnet 62 first case 63 second case 73 urea mixing pipe 74 SCR inlet pipe (exhaust outlet pipe body)
75 Bellows-shaped connecting pipe (flexible pipe)
91 Urea water tank 99 Insulation cover body

Claims (4)

A traveling machine body on which the engine is mounted, a first case for removing particulate matter in the exhaust gas of the engine, a second case for removing nitrogen oxides in the exhaust gas of the engine, and a first case in the first case. In a work vehicle comprising a urea mixing pipe connecting two cases and a urea water tank for supplying urea water to the urea mixing pipe,
An anti-vibration support structure for the engine on the traveling machine body, and an exhaust lead-out pipe body that fixes the first case and the urea mixing pipe to the upper position of the engine and is fixed to the traveling machine body side, A work vehicle characterized in that a flexible pipe is connected to an exhaust gas outlet side of the urea mixing pipe.   The first case and the urea mixing pipe are disposed on the engine side, the second case is disposed on the traveling machine body side, and an exhaust gas outlet of the urea mixing pipe and an exhaust gas inlet of the second case are disposed. The work vehicle according to claim 1, wherein a flexible pipe is connected therebetween.   The work vehicle according to claim 1, wherein a heat insulating cover body that covers the flexible pipe is provided, and the flexible pipe is disposed below a rear portion of a hood that covers the engine. A urea water tank for purifying exhaust gas; and a urea mixing pipe for supplying urea water from the urea water tank; The first case is supported in a posture in which the output shaft core line of the engine and the exhaust gas movement direction of the first case are parallel, and toward the one end side of the output shaft of the engine The exhaust gas outlet side of the first case is extended, the urea mixing pipe is supported in parallel with the exhaust gas movement direction of the first case, and the urea mixing pipe is directed toward the other end side of the output shaft of the engine. The work vehicle according to claim 1, wherein an exhaust gas outlet side of the vehicle is extended.

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