JP6442745B2 - Tractor - Google Patents

Description

The present invention relates to a tractor , and more particularly to a tractor including an exhaust purification device.

  2. Description of the Related Art Conventionally, work vehicles such as agricultural tractors and civil work wheel loaders are known. A work vehicle equipped with a diesel engine is equipped with an exhaust purification device that removes particulate matter (soot, particulates), nitrogen oxides (NOx) and the like contained in the exhaust gas.

  Some exhaust purification apparatuses include, for example, a filter case having a diesel particulate filter and a catalyst case having a urea selective reduction catalyst. Various proposals have been made regarding the arrangement of the filter case and the catalyst case (see Patent Document 1).

Japanese Patent Laying-Open No. 2015-20714

  Here, in the work vehicle, the engine and the cabin are supported by the frame directly or in a vibration-proof manner. When the filter case and / or the catalyst case of the exhaust purification device are arranged to be fixed to the frame or the cabin separately from the engine, a phase difference occurs between the vibration of the engine and the vibration of the filter case and / or the catalyst case. It is necessary to connect with flexible piping. A flexible pipe generally has a large surface area as represented by a bellows pipe. However, if the exhaust gas is not introduced into the catalyst case in a high temperature state, the purification efficiency deteriorates, which contradicts the design using a pipe having a large heat radiation area such as a bellows pipe.

It is an object of the present invention to provide a tractor including an exhaust purification device that absorbs vibration phase difference and suppresses a decrease in exhaust temperature.

A fuselage frame, an engine supported by vibration in the fuselage frame, a control unit supported by vibration in the fuselage frame, and a first case fixed to the engine to remove particulate matter in the exhaust of the engine; A heat-insulating structure that is fixed to the body frame and that forms part of an exhaust pipe that connects the first case and the second case, and a second case that reduces nitrogen oxides in the exhaust of the first case A telescopic tube having a pedestal, and a mounting member fixed to a supporting member fixed to the airframe frame, wherein a pedestal that supports the lower surface of the second case is attached. A cylindrical portion communicating with an outlet of the second case is formed on the upper surface of the second case, and an exhaust pipe for discharging the exhaust from the second case to the outside is provided. The entrance Together provided being covered with a gap on the outer periphery of the serial tubular portion is covered with a cover member, the cover member is one that is configured fixedly connected to the assist bars of the steering unit is there.

An injection nozzle that injects a reducing agent is provided in an exhaust pipe that connects the expansion tube and the second case .

  According to the present invention, the phase difference between the vibrations of the first case and the second case is absorbed by using the expansion and contraction tube 24 having a heat insulating structure in a part of the exhaust pipe connecting the first case and the second case. At the same time, a decrease in exhaust temperature can be suppressed. Exhaust gas is introduced into the second case at a high temperature, and good purification efficiency is obtained.

  Further, since the exhaust pipe and the second case do not transmit vibration to each other by providing an exhaust pipe that is covered with a gap around the outer periphery of the exhaust outlet portion of the second case, the vibration of the frame and the vibration of the cabin Even if a phase difference occurs, vibrations of the exhaust pipe and the second case do not interfere with each other.

  In addition, by providing an injection nozzle that injects the reducing agent in the exhaust pipe connecting the expansion tube and the second case, the exhaust gas kept at the expansion tube is transported to the injection nozzle, so that the exhaust and the reducing agent are improved. Can be reacted.

It is a perspective view of the tractor of one embodiment. It is a front view of the tractor of one embodiment. It is a right view of the tractor of one Embodiment. It is a top view of the tractor of one embodiment. It is an expansion right view of the exhaust gas purification device peripheral part of the tractor of one embodiment. It is an enlarged top view of the exhaust gas purification device peripheral part of the tractor of one embodiment. It is a perspective view of an engine and an exhaust emission control device. It is a figure explaining the support structure of the 2nd case and the 3rd exhaust pipe. It is the fragmentary sectional view which expanded the communication part of the 2nd case and the 3rd exhaust pipe. It is sectional drawing which shows an example of the expansion-contraction pipe | tube which has a heat insulation structure. It is sectional drawing which shows another example of the expansion-contraction pipe | tube which has a heat insulation structure.

  The technical idea of the present invention can be applied to any work vehicle. Below, it demonstrates using the tractor which is a typical work vehicle.

<Overall configuration of tractor>
In the present embodiment, a cabin specification tractor will be described as an example, but a lops specification tractor may be used. In the present embodiment, a tractor with a wheel specification is described as an example, but a tractor with a half crawler specification or a full crawler specification may be used.

  1 is a perspective view of the tractor 1, FIG. 2 is a front view of the tractor 1, FIG. 3 is a right view of the tractor 1, and FIG. 4 is a top view of the tractor 1. In the figure, the front-rear direction, the left-right direction, and the vertical direction of the tractor 1 are shown.

  The tractor 1 includes a frame 11, an engine 12, a transmission 13, a front axle 14, a rear axle 15, and a cabin (an example of a control unit) 16. The tractor 1 also includes an exhaust purification device 2 that purifies the exhaust of the engine 12.

  The frame 11 forms a skeleton at the front portion of the tractor 1. The frame 11 constitutes the chassis of the tractor 1 together with the transmission 13 and the rear axle 15. The engine 12 and the cabin 16 described below are supported by the frame 11 in a vibration-proof manner through vibration-proof rubber or the like.

  The engine 12 is a diesel engine and converts thermal energy obtained by burning fuel into kinetic energy. That is, the engine 12 generates rotational power by burning fuel. The engine 12 is connected to an engine control device (not shown). When the operator operates the accelerator pedal, the engine control device changes the operating state of the engine 12 according to the operation. Further, the exhaust purification device 2 is connected to the engine 12.

  The transmission 13 transmits the rotational power of the engine 12 to the front axle 14 and the rear axle 15. The rotational power of the engine 12 is input to the transmission 13 via a coupling mechanism. The transmission 13 is provided with a continuously variable transmission (HST or HMT, not shown). When the operator operates the shift lever, the continuously variable transmission changes the operating state of the transmission 13 according to the operation.

  The front axle 14 transmits the rotational power of the engine 12 to the front tire 141. The rotational power of the engine 12 is input to the front axle 14 via the transmission 13. The front axle 14 is provided with a steering device (not shown). When the operator operates the handle 162, the steering device changes the steering angle of the front tire 141 according to the operation.

  The rear axle 15 transmits the rotational power of the engine 12 to the rear tire 151. The rotational power of the engine 12 is input to the rear axle 15 via the transmission 13. The rear axle 15 is provided with a PTO output device (not shown). When an operator operates a PTO switch (not shown), the PTO output device transmits rotational power to a working machine to be pulled according to the operation.

  The cabin 16 has a cockpit inside, and a driver's seat 161, a handle 162, an accelerator pedal (not shown), a shift lever (not shown), a PTO switch, and the like are arranged. The operator can operate the tractor 1 by operating the handle 162, the accelerator pedal, the shift lever and the like while sitting on the driver's seat 161. The left front support column 165 and the right front support column 166 of the cabin 16 are provided with an assist bar 163 for catching when getting on and off. Both end portions of the assist bar 163 are fixed to the columns 165 and 166 with bolts via brackets 164, respectively.

<Exhaust gas purification device>
5 is an enlarged right side view of the periphery of the exhaust purification device 2 of the tractor 1, FIG. 6 is an enlarged top view of the periphery of the exhaust purification device 2 of the tractor 1, FIG. 7 is a perspective view of the engine 12 and the exhaust purification device 2, and FIG. FIG. 9 is a diagram for explaining a support structure for the second case and the third exhaust pipe, and FIG. 9 is a partial sectional view in which a communication portion between the second case and the third exhaust pipe is enlarged. In FIGS. 5 and 6, the bonnet is indicated by a virtual line.

  The exhaust purification device 2 is a device that removes particulate matter (soot, particulates), nitrogen oxides (NOx), etc. contained in the exhaust of the engine 12 and exhausts the purified exhaust to the outside. The exhaust purification device 2 includes a first case 21 as a diesel particulate filter (DPF) that removes particulate matter in the exhaust of the engine 12, and a urea selective catalyst that reduces nitrogen oxides in the exhaust of the first case 21. And a second case 22 as a reduction (SCR) system. The first case 21 is provided with an oxidation catalyst and a soot filter. In the second case 22, an SCR catalyst and an oxidation catalyst for urea selective catalyst reduction are installed.

  Further, the exhaust purification device 2 has a heat insulating structure connected to the first exhaust pipe 23 connected to the outlet 21b of the first case 21 and the outlet 23b of the first exhaust pipe 23 from the upstream side in the exhaust flow direction. A telescopic pipe 24, a second exhaust pipe 25 connecting the outlet 24 b of the telescopic pipe 24 and the inlet 22 a of the second case 22, and a third exhaust pipe 26 communicating with the outlet of the second case 22.

  Exhaust gas discharged from the engine 12 is discharged to the outside via the exhaust gas purification device 2. The exhaust purification device 2 reduces carbon monoxide, hydrocarbons, particulate matter, and nitrogen oxides in the exhaust.

  The 1st case 21 is comprised by the cylindrical shape extended in the front-back direction. An inlet 21a for taking in exhaust from the engine 12 is formed on the rear end side of the side surface of the first case 21, and an outlet 21b for exhausting air from the first case 21 is formed on the front end side of the side surface. The first case 21 is fixed to the upper surface of the engine 12 with bolts or the like. As a result, the first case 21 is directly supported by the engine 12 and vibrates together with the engine 12.

  The 2nd case 22 is comprised by the cylindrical shape extended in an up-down direction. An inlet 22a for taking in the exhaust from the second exhaust pipe 25 is formed on the lower end side of the left side surface of the second case 22, and an outlet for exhausting from the second case 22 is formed on the upper surface. The second case 22 is fixed to the frame 11 via a plurality of support members (see FIG. 8). As a result, the second case 22 is equivalent to being directly fixed to the frame 11 and vibrates together with the frame 11. The second case 22 may be fixed to the cabin 16 instead of the frame 11. In this case, the second case 22 vibrates together with the cabin 16.

  The first exhaust pipe 23 constitutes a part of an exhaust pipe connecting the first case 21 and the second case 22, an inlet 23 a connected to the outlet 21 b of the first case 21, and an inlet 24 a of the telescopic pipe 24. And an outlet 23b connected to the. By connecting the inlet 23 a of the first exhaust pipe 23 to the first case 21, the first exhaust pipe 23 is supported by the first case 21. Therefore, the first exhaust pipe 23 vibrates together with the first case 21. That is, it vibrates together with the engine 12.

  The telescopic tube 24 forms part of an exhaust pipe that connects the first case 21 and the second case 22, and includes an inlet 24 a connected to the outlet 23 b of the first exhaust pipe 23 and an inlet of the second exhaust pipe 25. And an outlet 24b connected to 25a. The expansion tube 24 is supported by the first exhaust pipe 23 by connecting the inlet 24 a of the expansion tube 24 to the first exhaust pipe 23. Therefore, the vicinity of the inlet 24 a of the telescopic tube 24 vibrates together with the first exhaust pipe 23. That is, it vibrates together with the engine 12.

  On the other hand, the extension tube 24 is supported by the second exhaust pipe 25 by connecting the outlet 24 b of the extension pipe 24 to the second exhaust pipe 25. Therefore, the vicinity of the outlet 24 b of the telescopic tube 24 vibrates together with the second exhaust pipe 25. Since the inlet 24 a and the outlet 24 b of the telescopic tube 24 are fixed to different members, a phase difference occurs between the vibrations of the two, but both vibrations are absorbed by the stretchability of the telescopic tube 24. As described above, in the structure in which the engine 12 is supported by vibration isolation, it is effective to use the telescopic tube 24 when the exhaust purification device 2 is provided.

  In addition, by using the telescopic tube 24, it is possible to absorb the phase difference of vibration in the exhaust system as described above. However, since the surface area is increased, the exhaust temperature is lowered. A decrease in exhaust temperature leads to deterioration in exhaust purification efficiency. Therefore, in this embodiment, the expansion of the expansion tube 24 is provided with a heat insulating structure to suppress a decrease in the exhaust temperature. As a result, the exhaust gas is introduced into the second case 22 in a high temperature state, and good purification efficiency is obtained. The heat insulation structure of the telescopic tube 24 will be described later.

  The second exhaust pipe 25 forms a part of the exhaust pipe connecting the first case 21 and the second case 22, and includes an inlet 25 a connected to the outlet 24 b of the telescopic pipe 24 and an inlet 22 a of the second case 22. And an outlet 25b connected to the. By connecting the outlet 25 b of the second exhaust pipe 25 to the second case 22, the second exhaust pipe 25 is supported by the second case 22. Therefore, the second exhaust pipe 25 vibrates together with the second case 22. That is, it vibrates together with the frame 11 or the cabin 16.

  A urea water injection nozzle 28 is disposed in the middle of the second exhaust pipe 25. The urea water injection nozzle 28 is connected to a pump and a urea water tank (not shown), and is configured to inject urea water into the second exhaust pipe 25. The injected urea water is mixed with the exhaust gas in the second exhaust pipe 25. Therefore, the second exhaust pipe 25 has a role as a mixer. The downstream side of the second exhaust pipe 25 from the urea water injection nozzle 28 is preferably a double pipe from the viewpoint of maintaining the exhaust gas and urea water at a temperature at which they can react.

  Thus, by providing the injection nozzle 28 on the downstream side of the expansion / contraction tube 24, the exhaust gas kept at the expansion / contraction tube 24 is transported to the injection nozzle 28, so that the exhaust gas and urea water can react well.

  As shown in FIG. 7, the third exhaust pipe 26 is an exhaust pipe that exhausts the exhaust from the second case 22 to the outside, and is opened to the atmosphere with an inlet 26 a that communicates with the outlet of the second case 22. And an outlet 26b. A bracket 221 for supporting the second case 22 is fixed to the upper surface of the second case 22, and a cylindrical portion 221 a communicating with the outlet of the second case 22 is formed on the bracket 221. And the inlet 26a of the 3rd exhaust pipe 26 is covered with the space | gap in the outer periphery of the cylinder part 221a (refer FIG. 9). Therefore, the third exhaust pipe 26 and the second case 22 do not transmit vibrations to each other.

  As shown in FIG. 8, an L-shaped bracket 221 is fixed to the upper surface of the second case 22, and a bracket 27 is fixed to the lower surface. The bracket 221 and the bracket 27 are connected by a channel steel 29. The grooved steel 29 can suppress left and right shaking of the second case 22. The bracket 27 includes a pedestal 271 that supports the lower surface of the second case 22, a rectangular steel pipe 272 that extends leftward from the pedestal 271, and a U-shaped attachment portion 273 that extends rearward from the steel pipe 272. .

  Both end portions of the attachment portion 273 are fixed to the two support members 111 fixed to the frame 11, respectively. Therefore, the second case 22 is fixed to the frame 11. With such a configuration, the second case 22 vibrates together with the frame 11. A battery frame 30 extending downward is fixed to the right surface of the mounting portion 273, and a battery base 31 on which the battery is placed is fixed to the battery frame 30.

  The third exhaust pipe 26 is covered with a cover member 261. The third exhaust pipe 26 is fixed to the cover member 261, and the cover member 261 is connected to the assist bar 163 of the cabin 16 through two upper and lower brackets 262. Therefore, the third exhaust pipe 26 is fixed to the cabin 16. With such a configuration, the third exhaust pipe 26 vibrates together with the cabin 16.

  As described above, since the third exhaust pipe 26 and the second case 22 do not transmit vibrations to each other, even if there is a phase difference between the vibration of the frame 11 and the vibration of the cabin 16, the third exhaust pipe 26 and the second case 22. The vibration of the case 22 does not interfere.

<Expandable tube with heat insulation structure>
The telescopic tube 24 having a heat insulating structure can be combined with various telescopic tubes and various heat insulating structures. FIG. 10 is a cross-sectional view showing an example of the telescopic tube 24 having a heat insulating structure. In FIG. 10, the telescopic tube 24 having a heat insulating structure is a bellows tube around which a heat insulating material is wound. The telescopic tube 24 having this heat insulating structure includes a bellows tube 241, a heat insulating material 242, a cylindrical member 243, a first lid member 244, and a second lid member 245.

  The bellows tube 241 has a straight tube joined to both ends of a metal cylinder provided with pleats, and a general-purpose product can be used. The heat insulating material 242 is made of glass wool or urethane foam, and covers at least the bellows portion of the bellows tube 241. The heat insulating material 242 can suppress a decrease in exhaust temperature at the bellows tube 241 portion.

  The cylinder member 243 is a metal cylinder that covers the heat insulating material 242. The first lid member 244 is a donut-shaped metal plate, and an outer edge portion 244 a is joined to the inner peripheral surface of one end of the cylindrical member 243, and the inner edge portion 244 b is joined to the outer peripheral surface of the bellows tube 241. For the joining here, for example, welding can be used.

  The second lid member 245 is the same donut-shaped metal plate as the first lid member 244, the outer edge portion 245 a is positioned near the other end of the cylindrical member 243, and the inner edge portion 244 b is joined to the outer periphery of the bellows tube 241. Yes. Since the 2nd cover material 245 is not joined to the cylinder material 243, it can move freely according to expansion and contraction of the bellows portion. In addition, the outer edge portion 245 a of the second lid member 245 may be bent so as to overlap the outer periphery of the cylindrical member 243. According to this, the intrusion of dust into the cylinder member 243 can be suppressed. Note that the second lid member 245 may be omitted as long as dust can be allowed to enter.

  According to the bellows tube 241 around which the heat insulating material 242 is wound, the bellows tube 241 can absorb the phase difference between the vibrations on the inlet 24a side and the outlet 24b side, and the heat insulating material 242 suppresses a decrease in the exhaust temperature. be able to. In addition to the heat insulating material 242 and the bellows tube 241, by using the cylindrical material 243, the first lid material 244, and the second lid material 245, it can be configured as a general-purpose product and can be manufactured at low cost. it can.

  FIG. 11 is a cross-sectional view showing another example of the telescopic tube 24 having a heat insulating structure. In FIG. 11, the expansion tube 24 having a heat insulating structure is a double structure expansion tube. The telescopic tube 24 having this heat insulating structure includes an interlock tube 24A and a bellows tube 24B.

  The interlock pipe 24A is obtained by winding a strip steel in a spiral shape and joining straight pipes to both ends of an interlock material formed by meshing adjacent portions. The bellows tube 24B is a metal cylinder provided with pleats. The bellows tube 24B covers the outer peripheral surface of the interlock tube 24A, and the portions protruding to the inner surface side of the bellows portion are respectively joined to the steel strip. Thereby, a heat insulation effect is acquired in the air layer which the bellows tube 24B encloses, having elasticity. The outer periphery of the bellows tube 24A may be reinforced with a metal mesh.

  According to such a double-structured telescopic pipe, the interlock pipe 24A can absorb the phase difference between the vibrations on the inlet 24a side and the outlet 24b side, and the air temperature contained in the bellows pipe 24B reduces the exhaust temperature. Can be suppressed.

  As described above, according to the present embodiment, when the exhaust purification device 2 is provided in a structure in which the engine 12 is supported for vibration isolation, the vibration phase difference in the exhaust purification device 2 is obtained by using the telescopic tube 24 having a heat insulating structure. Can be absorbed and a decrease in the exhaust temperature can be suppressed.

1 Tractor (work vehicle)
11 Frame 12 Engine 16 Cabin (control part)
21 First Case 22 Second Case 24 Telescopic Tube 28 Injection Nozzle 241 Bellows Tube 242 Heat Insulating Material 243 Tube Material 244 First Lid Material 245 Second Lid Material

Claims (2)

The fuselage frame,
An anti-vibration supported engine on the body frame;
A steering unit that is supported in a vibration-proof manner on the body frame;
A first case fixed to the engine to remove particulate matter in the exhaust of the engine;
A second case fixed to the body frame for reducing nitrogen oxides in the exhaust of the first case;
A tractor comprising: a telescopic pipe having a heat insulating structure that constitutes a part of an exhaust pipe connecting the first case and the second case;
The mounting member fixed to the support member fixed to the body frame is configured by attaching a pedestal that supports the lower surface of the second case,
On the upper surface of the second case, a cylindrical portion communicating with the outlet of the second case is formed, and an exhaust pipe for discharging the exhaust from the second case to the outside is provided.
The exhaust pipe is provided with an inlet covering the outer periphery of the cylindrical portion with a gap, and is covered with a cover member,
The cover member is configured to be connected and fixed to the assist bar of the control unit.
A tractor characterized by that. The tractor according to claim 1, wherein an injection nozzle for injecting a reducing agent is provided in an exhaust pipe connecting the telescopic pipe and the second case.

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