JP2015040522A - Construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain leakage of urea water stored in a urea water tank to an outside even when a vehicle body is oscillated.SOLUTION: A respiration pipe 21 is attached to a urea water tank 14 in order to circulate gas between an inside and an outside of the urea water tank 14, a partition plate 22 with a lower hole having a vent hole 22A and a partition plate 23 with an upper hole having a vent hole 23A are provided in a base end side cylindrical part 21A of the respiration pipe 21 at intervals in a longitudinal direction of the base end side cylindrical part 21A. The partition plate 22 with the lower hole and the partition plate 23 with the upper hole are arranged in such a manner that the vent hole 22A and the vent hole 23A are not overlapped with each other in the longitudinal direction of the respiration pipe 21. Accordingly, even when a part of the urea water tries to infiltrate the base end side cylindrical part 21A through a base end side opening end 21C of the respiration pipe 21, infiltration of the urea water can be cut off by the partition plate 22 with the lower hole and the partition plate 23 with the upper hole.

Description

  The present invention relates to a construction machine such as a hydraulic excavator equipped with a urea selective reduction catalyst and a urea water tank for removing nitrogen oxides contained in exhaust gas.

  In general, a hydraulic excavator, which is a typical example of a construction machine, has a vehicle body composed of a self-propelled lower traveling body and an upper revolving body that is turnably mounted on the lower traveling body. Further, a working device for performing excavation work or the like is provided so as to be able to move up and down.

  A diesel engine is used as an engine serving as a power source for the upper rotating body of the hydraulic excavator. This diesel engine is said to emit a large amount of nitrogen oxides (hereinafter referred to as NOx). For this reason, the exhaust gas purification device is mounted on the hydraulic excavator in order to purify NOx contained in the exhaust gas discharged from the diesel engine.

  The exhaust gas purification device includes, for example, a urea selective reduction catalyst that is provided in an exhaust pipe of an engine to remove nitrogen oxides in exhaust gas, a urea water tank that stores a urea aqueous solution (urea water) as a reducing agent, and the urea water A urea water injection valve that is connected to the tank via a pipe and injects urea water in the urea water tank to the upstream side of the urea selective reduction catalyst.

  Here, the urea water tank is provided with a respiratory tube for adjusting its internal pressure to a pressure substantially equal to the atmospheric pressure, and this respiratory tube is formed of a hollow cylindrical body (pipe body), and the proximal end side is the above-mentioned It opens to the inside of the urea water tank and the tip side opens to the outside of the urea water tank, allowing gas to flow between the inside and outside of the urea water tank (see, for example, Patent Document 1).

JP 2012-62691 A

  However, since the urea water tank constituting the exhaust gas purification device is usually mounted on the upper swing body of the hydraulic excavator, the urea body is vibrated when the hydraulic excavator travels or during excavation work using the working device. The liquid level of the urea water stored in the water tank begins to shake violently.

  For this reason, when the excavator is traveling or excavating, the vehicle body vibrates greatly, so that a part of the urea water enters the respiratory pipe provided in the urea water tank, and the urea water tank passes through the distal end of the respiratory pipe. There is a problem of leaking outside.

  The present invention has been made in view of the above-described problems of the prior art, and provides a construction machine capable of suppressing leakage of urea water stored in a urea water tank to the outside even when the vehicle body vibrates. It is an object.

  In order to solve the above-described problems, the present invention relates to a self-propelled vehicle body, an engine mounted on the vehicle body, and a urea selective reduction catalyst provided in an exhaust pipe of the engine to remove nitrogen oxides in exhaust gas. An exhaust gas purifying device, a urea water injection valve that is provided in the exhaust gas purifying device and injects urea water as a reducing agent upstream of the urea selective reduction catalyst, and is supplied to the urea water injection valve A urea water tank comprising a hollow container for storing urea water, and a base end side provided in the urea water tank that opens to the inside of the urea water tank and a tip side that opens to the outside of the urea water tank; It is applied to a construction machine provided with a breathing tube that allows gas to flow between the inside and the outside.

  A feature of the configuration adopted by the invention of claim 1 is that the urea water in the urea water tank is prevented from leaking outside through the distal end side of the respiratory tube due to vibration of the vehicle body inside the respiratory tube. For this reason, a barrier portion having a narrow passage as a part of the respiratory tract is provided.

  The invention of claim 2 is that a plurality of the barrier portions are provided at different positions in the length direction of the respiratory tract.

  According to a third aspect of the present invention, the barrier portion is constituted by a plurality of perforated partition plates attached to an inner peripheral surface on the proximal end side of the respiratory tract, in which a vent hole through which gas flows is formed. The two adjacent partition walls with holes among the partition walls with holes are arranged so that the vent holes do not overlap in the length direction of the respiratory tract.

  According to a fourth aspect of the present invention, the barrier portion includes a plurality of partition plates attached in a state where a passage through which gas flows is formed between the inner peripheral surface on the proximal end side of the respiratory tract and the inner peripheral surface. The two partition plates adjacent to each other among these partition plates are configured such that the passage between the inner peripheral surface of the respiratory tract does not overlap in the length direction of the respiratory tract. There is.

  According to a fifth aspect of the present invention, gas flows between the barrier portion and the inner peripheral surface of the respiratory tract by denting the outer peripheral surface of the proximal end side of the respiratory tract toward the inside of the respiratory tract. It comprises a plurality of recesses forming a passage, and two adjacent recesses among these recesses are such that the passage between the inner peripheral surface of the respiratory tract is the length of the respiratory tract The arrangement is such that they do not overlap in the direction.

  According to the first aspect of the present invention, the vehicle body vibrates when the construction machine is running or working, and the liquid level of the urea water stored in the urea water tank is vigorously shaken. Enter the respiratory tract through the proximal opening. However, since the barrier part is provided inside the respiratory tract, the barrier part can prevent the urea water that has entered the respiratory tract from flowing to the distal end side of the respiratory tract. As a result, the urea water can be prevented from leaking outside from the distal end side of the respiratory tract, and the urea water stored in the urea water tank can be prevented from decreasing at an early stage.

  According to the invention of claim 2, by providing a plurality of barrier portions at positions different from each other in the length direction of the respiratory tract, a plurality of urea water that has entered the respiratory tract flows to the distal end side of the respiratory tract. Can be blocked by the barrier portion.

  According to the invention of claim 3, even if a part of the urea water enters the respiratory tract through the opening on the proximal end side of the respiratory tract due to the vibration of the urea aqueous tank, the urea aqueous It collides with a plurality of perforated partition plates attached to the inner peripheral surface on the end side. As a result, the urea water can be prevented from flowing from the proximal end side to the distal end side of the respiratory tract, and the urea water can be prevented from leaking outside from the distal end side of the respiratory tract.

  On the other hand, since a vent hole is formed in the partition wall plate with holes, the pressure in the urea water tank can be adjusted by allowing gas to flow between the inside and outside of the urea water tank through the vent hole. Can do. In this case, the plurality of partition walls with holes are arranged so that the ventilation holes of the adjacent two partition walls with holes do not overlap in the length direction of the respiratory tract. It is possible to prevent the air from flowing to the distal end side of the respiratory tube through the vent hole.

  According to the invention of claim 4, the urea water that has entered the respiratory tract collides with the plurality of partition plates attached to the inner peripheral surface on the proximal end side of the respiratory tract, so that the urea water becomes the base of the respiratory tract. The flow from the end side to the tip side can be prevented, and urea water can be prevented from leaking outside from the tip side of the respiratory tract. On the other hand, since a passage is formed between each partition plate and the inner peripheral surface of the respiratory tract, the inside of the urea water tank communicates with the outside through this passage to adjust the pressure in the urea water tank. be able to. In this case, two adjacent partition plates among the plurality of partition plates are arranged so that the passage between the inner peripheral surface of the respiratory ducts does not overlap in the longitudinal direction of the respiratory ducts. It is possible to prevent the urea water that has entered the air from flowing to the distal end side of the respiratory tube through a passage formed between each partition plate and the respiratory tube.

  According to the fifth aspect of the present invention, the urea water that has entered the respiratory tract collides with a plurality of concave portions provided on the proximal end side of the respiratory tract, so that the urea aqueous solution is distal to the distal end side of the respiratory tract. It is possible to prevent the urea water from leaking out from the distal end side of the respiratory tube. On the other hand, since a passage is formed between each recess and the inner peripheral surface of the respiratory tract, the inside and outside of the urea water tank communicate with each other through this passage to adjust the pressure in the urea water tank. can do. In this case, the two adjacent recesses among the recesses are arranged so that the passages between the inner peripheral surfaces of the respiratory ducts do not overlap in the longitudinal direction of the respiratory ducts. It is possible to prevent the urea water that has entered the water from flowing to the distal end side of the respiratory tube through a passage formed between each recessed portion and the respiratory tube.

  Moreover, each recess can be easily formed by recessing the outer peripheral surface on the proximal end side of the respiratory tract toward the inside of the respiratory tract. Therefore, the configuration of the entire respiratory tract can be simplified as compared with a configuration in which a barrier portion made of a member different from the respiratory tract is attached to the inner peripheral side of the respiratory tract, which contributes to a reduction in manufacturing cost. it can.

It is a front view which shows the hydraulic shovel applied to the 1st Embodiment of this invention. It is a block diagram which shows the connection relationship of an exhaust pipe, an exhaust-gas purification apparatus, a urea water injection valve, a urea water tank, etc. with an engine. It is sectional drawing which shows a urea water tank, a respiratory tube, etc. It is an expanded sectional view showing a respiratory tract by a 1st embodiment, a partition board with each hole, etc. It is sectional drawing which looked at the respiratory duct and the partition board with a lower hole from the arrow VV direction in FIG. It is sectional drawing which looked at the respiratory tract and the partition plate with an upper hole from the arrow VI-VI direction in FIG. It is an expanded sectional view similar to FIG. 4 which shows the respiratory tract by the 2nd Embodiment, each partition board, etc. It is sectional drawing which looked at the respiratory tract and the lower side partition board from the arrow VIII-VIII direction in FIG. It is sectional drawing which looked at the respiratory tract and the upper partition board from the arrow IX-IX direction in FIG. It is an expanded sectional view similar to FIG. 4 which shows the respiratory tract by the 3rd Embodiment, each recessed hollow part, etc. It is sectional drawing which looked at the respiratory tract and the lower side recessed part from the arrow XI-XI direction in FIG. It is sectional drawing which looked at the respiratory tract and the upper side recessed part from the arrow XII-XII direction in FIG. It is sectional drawing which shows the state which forms each recessed part in a respiratory tract. It is an expanded sectional view similar to FIG. 4 which shows the respiratory tract by the 1st modification. It is an expanded sectional view similar to FIG. 4 which shows the respiratory tract by the 2nd modification.

  Hereinafter, as a construction machine according to an embodiment of the present invention, a crawler type hydraulic excavator will be described as an example and described in detail with reference to the accompanying drawings.

  1 to 6 show a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a hydraulic excavator as a typical example of a construction machine. The hydraulic excavator 1 includes a crawler-type lower traveling body 2 that can be self-propelled and an upper revolving body 3 that is rotatably mounted on the lower traveling body 2. A working device 4 is provided on the front side of the upper swing body 3 so as to be able to move up and down. The working device 4 performs excavation work of earth and sand.

  The upper swing body 3 is a swing frame 5 serving as a base mounted on the lower traveling body 2 so as to be swingable, and a counterweight 6 provided on the rear end side of the swing frame 5 to balance the weight with the work device 4. A cab 7 provided on the left side of the front part of the swivel frame 5 on which an operator gets on, and a building cover provided on the front side of the counterweight 6 and accommodates an engine 9, a radiator 11, an exhaust gas purifying device 12, etc. 8 is roughly constituted. A tool box 8A is provided on the right side of the front portion of the building cover 8, and a urea water tank 14 described later is accommodated in the tool box 8A.

  Reference numeral 9 denotes an engine provided on the rear side of the turning frame 5. The engine 9 is constituted by a diesel engine and is mounted on the turning frame 5 with a crankshaft (not shown) extending horizontally in the left and right directions. Has been. The engine 9 drives a hydraulic pump (not shown), and the exhaust gas discharged from the engine 9 is discharged to the outside through the exhaust pipe 10.

  As shown in FIG. 2, the engine 9 is provided with a water jacket 9 </ b> A through which engine coolant circulates, and the water jacket 9 </ b> A is connected to the radiator 11. The engine coolant is circulated between the water jacket 9A and the radiator 11 by a water pump 9B provided in the engine 9, and the heat of the engine coolant is released to the atmosphere by the radiator 11. Further, the engine cooling water is also used as a heating fluid for warming urea water in a urea water tank 14 to be described later, and the engine cooling water as the heating fluid is passed through a heating pipe 18 to be described later. 14 is distributed within the network.

  Here, the engine 9 made of a diesel engine is highly efficient and excellent in durability, but harmful substances such as nitrogen oxides (NOx) are discharged together with the exhaust gas. For this reason, the exhaust pipe 10 provided in the engine 9 is provided with an exhaust gas purification device 12 described later.

  Reference numeral 12 denotes an exhaust gas purification device provided in the middle of the exhaust pipe 10, and the exhaust gas purification device 12 is disposed in the vicinity of the engine 9 via a support bracket or the like (not shown). The exhaust gas purification device 12 collects particulate matter (PM) in the exhaust gas exhausted from the engine 9 and burns and removes it, and also removes nitrogen oxide (NOx) contained in the exhaust gas with an aqueous urea solution ( It is decomposed into nitrogen and water using urea water) and purified.

  Here, as shown in FIG. 2, the exhaust gas purification device 12 is formed of a hollow cylindrical body extending in the axial direction, and has a cylindrical case 12A connected to the exhaust pipe 10 and a cylindrical case in the exhaust gas flow direction. Particles that are provided on the downstream side of 12A and are accommodated on the upstream side in the cylindrical case 12A, and are collected and burned and removed by the tail tube 12B serving as an exhaust port protruding upward. The particulate matter removal filter 12C, a urea selective reduction catalyst 12D accommodated downstream of the particulate matter removal filter 12C, and an oxidation catalyst 12E accommodated downstream of the urea selective reduction catalyst 12D are roughly configured. Has been.

  A urea water injection valve 13, which will be described later, is provided in a portion of the cylindrical case 12A upstream of the urea selective reduction catalyst 12D, and the urea water injection valve 13 is introduced into the urea selective reduction catalyst 12D. Urea water as a reducing agent is injected toward the exhaust gas. As a result, the urea selective reduction catalyst 12D accommodated in the cylindrical case 12A selectively causes the nitrogen oxides contained in the exhaust gas to undergo a reduction reaction with ammonia hydrolyzed from the urea water, and decomposes into nitrogen and water. This removes nitrogen oxides from the exhaust gas. Note that the oxidation catalyst 12E disposed downstream of the urea selective reduction catalyst 12D in the cylindrical case 12A oxidizes and decomposes excess ammonia without being able to react with, for example, nitrogen oxides.

  Reference numeral 13 denotes a urea water injection valve provided upstream of the urea selective reduction catalyst 12D in the cylindrical case 12A. The urea water injection valve 13 injects (sprays) urea water (urea aqueous solution) as a reducing agent stored in a urea water tank 14 described later toward the exhaust gas upstream of the urea selective reduction catalyst 12D. is there. Thereby, uniform ammonia mixed exhaust gas can be sent into the urea selective reduction catalyst 12D, and the reduction reaction by the urea selective reduction catalyst 12D can be performed efficiently.

  Reference numeral 14 denotes a urea water tank that stores urea water as a reducing agent, and the urea water tank 14 is accommodated in a tool box 8A disposed in the upper swing body 3 of the excavator 1, for example. As shown in FIG. 3, the urea water tank 14 has a bottom face 14A, a top face 14B facing the bottom face 14A in the upward and downward directions, and a peripheral wall face 14C connecting the bottom face 14A and the top face 14B. It consists of a box. A cylindrical opening 14D is provided on the upper surface 14B of the urea water tank 14, and this opening 14D is detachably closed by a lid 14E. The lid body 14E of the urea water tank 14 is provided with a urea water supply pipe 15, a urea water return pipe 16, a heating pipe 18, and a breathing pipe 21, which will be described later.

  Reference numeral 15 denotes a urea water supply pipe for connecting the urea water tank 14 and the urea water injection valve 13. One end side of the urea water supply pipe 15 opens near the bottom surface 14A of the urea water tank 14 while being attached to the lid 14E of the urea water tank 14, and the other end side of the urea water supply pipe 15 is the urea water injection valve. 13 is connected. A urea water supply device 17 to be described later is connected to a midway portion of the urea water supply pipe 15.

  Reference numeral 16 denotes a urea water return pipe for connecting the urea water tank 14 and a urea water supply device 17 described later. One end side of the urea water return pipe 16 is connected to the urea water supply device 17, and the other end side of the urea water return pipe 16 is attached to the lid body 14 </ b> E of the urea water tank 14 and the upper surface 14 </ b> B of the urea water tank 14. Open in the vicinity.

  A urea water supply device 17 is provided in the middle of the urea water supply pipe 15, and the urea water supply device 17 includes a pump, a switching valve, a controller, and the like, and an operation state of the engine 9 (for example, exhaust gas discharge amount). Etc.), the desired urea water is supplied to the urea water injection valve 13. The urea water supply device 17 is connected to an intermediate portion of the urea water supply pipe 15 and to the other end of the urea water return pipe 16.

  The urea water supply device 17 sucks urea water in the urea water tank 14 through the urea water supply pipe 15, and supplies an appropriate amount of urea water according to the operation state of the engine 9 to the urea water injection valve 13, thereby urea water. Urea water is sprayed into the exhaust pipe 10 from the injection valve 13. On the other hand, the urea water surplus in the urea water supply device 17 returns to the urea water tank 14 through the urea water return pipe 16.

  Reference numeral 18 denotes a heating pipe for warming the urea water stored in the urea water tank 14, and the heating pipe 18 circulates engine cooling water as a warming fluid for warming the urea water. A part of the heating pipe 18 is disposed in the urea water tank 14 while being attached to the lid body 14E of the urea water tank 14, and the engine cooling is performed in the heating pipe 18 disposed in the urea water tank 14. By circulating the water, the urea water stored in the urea water tank 14 can be appropriately heated.

  Next, the respiratory tube 21 according to the first embodiment provided in the urea water tank 14 will be described with reference to FIGS. 4 to 6.

  Reference numeral 21 denotes a breathing pipe provided in the urea water tank 14. The breathing pipe 21 is attached to the lid body 14 </ b> E of the urea water tank 14, and gas flows between the inside and outside of the urea water tank 14. The internal pressure of the urea water tank 14 is adjusted to about atmospheric pressure. The respiratory tube 21 is formed of a cylindrical body (pipe body) bent in an L shape as a whole, and includes a proximal-side cylindrical portion 21A that extends upward and downward from the inside of the urea water tank 14 to the outside, and a proximal end. It is constituted by a distal end side cylindrical portion 21B which is bent from the upper end side of the side cylindrical portion 21A and extends outside the urea water tank 14 in the horizontal direction.

  The end portion of the proximal end side cylindrical portion 21A of the breathing tube 21 becomes a proximal end side opening end 21C that opens into the urea water tank 14, and the proximal end opening end 21C avoids intrusion of urea water. The urea water tank 14 is disposed in the vicinity of the upper surface 14B of the urea water tank 14 above the liquid level L of the urea water. In addition, inside the base end side cylindrical portion 21A, partition walls 22 and 23 with holes, which will be described later, are provided above the base end side opening end 21C. On the other hand, the end portion of the distal end side cylindrical portion 21 </ b> B of the respiratory tube 21 is a distal end side opening end 21 </ b> D that opens to the outside of the urea water tank 14.

  The breathing pipe 21 circulates gas between the inside and outside of the urea water tank 14 according to fluctuations in the liquid level L of the urea water stored in the urea water tank 14 and changes in the outside air temperature (breathing). ) To adjust the pressure in the urea water tank 14 to about atmospheric pressure. The respiratory tube 21 may be attached to a location other than the lid body 14E of the urea water tank 14, for example, the upper surface 14B.

  Reference numeral 22 denotes a partition plate with a lower hole as a barrier portion provided inside the proximal end cylindrical portion 21A constituting the respiratory tube 21, and the partition plate 22 with the lower hole is formed from a proximal end opening end 21C. Is also arranged on the upper side. As shown in FIGS. 4 and 5, the partition plate 22 with the lower hole is formed in a disc shape having an outer diameter that is equal to the inner diameter of the inner peripheral surface 21 </ b> A <b> 1 of the base end side cylindrical portion 21 </ b> A. One vent hole 22A penetrating in the thickness direction is formed at a position spaced apart (eccentric) in the radial direction from the center of the partition plate 22 with the lower hole.

  The partition plate 22 with the lower hole is fixed to the inner peripheral surface 21A1 of the base end side cylindrical portion 21A by using means such as press-fitting, adhesion, and welding so as to close it. Accordingly, when the hydraulic excavator 1 is operated, the level L of the urea water stored in the urea water tank 14 sways, and a part of the urea water passes through the proximal end opening end 21 </ b> C of the respiratory tube 21 in the proximal end cylindrical portion 21 </ b> A. Even when trying to enter, the partition plate 22 with the lower hole can prevent the urea water from entering. On the other hand, the vent hole 22 </ b> A of the partition plate 22 with the lower hole adjusts the pressure in the urea water tank 14 by allowing gas to flow between the inside and the outside of the urea water tank 14.

  23 indicates a partition plate with an upper hole as a barrier portion provided at a position different from the partition plate 22 with a lower hole in the length direction of the respiratory tube 21, and the partition plate with the upper hole has a lower hole. It is located above the partition plate 22 and is provided inside the proximal end side cylindrical portion 21A. The partition plate 23 with the upper hole is formed in a disk shape having an outer diameter that is equal to the inner diameter of the inner peripheral surface 21A1 of the base end side cylindrical portion 21A, like the partition plate 22 with the lower hole. One vent hole 23A penetrating in the thickness direction is formed at a position spaced apart (eccentric) in the radial direction from the center of the partition plate 23 with the upper hole.

  The partition plate 23 with the upper hole is fixed to the inner peripheral surface 21A1 of the base end side cylindrical portion 21A by using means such as press-fitting, adhesion, and welding, like the partition plate 22 with the lower hole. ing. In this case, as shown in FIG. 5 and FIG. 6, the vent hole 22A of the partition plate 22 with the lower hole and the vent hole 23A of the partition plate 23 with the upper hole are mutually located with respect to the center of the base end side cylindrical portion 21A. It is arranged at a position shifted by 180 degrees. As described above, the two adjacent partition plates 22 with the lower hole and the partition plate 23 with the upper hole are arranged so that the vent hole 22A and the vent hole 23A do not overlap in the length direction of the respiratory tube 21. ing.

  Note that the partition plate 22 with the lower hole and the partition plate 23 with the upper hole are within the range in which the vent hole 22A and the vent hole 23A do not overlap in the longitudinal direction of the respiratory tube 21. It is good also as a structure arrange | positioned in the position which shifted | deviated with the moderate angle (for example, 90 degree | times) with respect to the center.

  Therefore, even when the level L of the urea water stored in the urea water tank 14 sways and a part of the urea water passes through the vent hole 22A of the partition plate 22 with the lower hole, the partition plate 22 with the lower hole is provided. The vent hole 22A and the vent hole 23A of the upper-side partition wall plate 23 are displaced from each other by 180 degrees with respect to the center of the base end side cylindrical portion 21A, and thus pass through the vent hole 22A of the lower-side partition wall plate 22 The urea water thus made can be blocked by the partition plate 23 with the upper hole.

  On the other hand, the vent hole 23A of the partition plate 23 with the upper hole, like the vent hole 22A of the partition plate 22 with the lower hole, allows the urea water to flow through between the inside and the outside of the urea water tank 14. The pressure in the tank 14 is adjusted.

  The hydraulic excavator 1 according to the first embodiment has the above-described configuration. Next, the operation thereof will be described.

  First, the operator gets on the cab 7 and operates the engine 9. The operator can drive the hydraulic excavator 1 by operating a travel operation lever (not shown) disposed in the cab 7 and operate a work operation lever (not shown). By doing so, excavation work of earth and sand can be performed using the work device 4.

  When the engine 9 is in operation, the exhaust gas flowing from the exhaust pipe 10 into the cylindrical case 12A of the exhaust gas purification device 12 contains particulate matter (PM) and nitrogen oxides (NOx) that are harmful substances. ing. On the other hand, the particulate matter removing filter 12C arranged in the cylindrical case 12A collects particulate matter (PM) contained in the exhaust gas, and burns and removes it.

  On the other hand, urea water is injected (sprayed) from the urea water injection valve 13 to the exhaust gas that has passed through the particulate matter removal filter 12C. The exhaust gas into which the urea water is injected becomes an ammonia mixed exhaust in which ammonia hydrolyzed from urea water or urea water is mixed, and is introduced into the urea selective reduction catalyst 12D. The urea selective reduction catalyst 12D selectively reduces the nitrogen oxide contained in the exhaust gas by ammonia hydrolyzed from the urea water, and decomposes and purifies it into nitrogen and water. The exhaust gas in which nitrogen oxides are decomposed (purified) by the urea selective reduction catalyst 12D is exhausted into the atmosphere through the tail pipe 12B after excess ammonia is oxidized and decomposed by the oxidation catalyst 12E. As a result, the exhaust gas purification device 12 can reduce the amount of particulate matter and nitrogen oxides contained in the exhaust gas.

  Here, when the hydraulic excavator 1 is operated, the liquid level L of the urea water stored in the urea water tank 14 sways violently. As a result, part of the urea water enters the respiratory tube 21 through the proximal end side opening end 21C of the respiratory tube 21 (base end side cylindrical portion 21A), and enters the outside of the urea water tank 14 through the distal end side opening end 21D. There is a risk of leakage.

  On the other hand, in the first embodiment, a partition plate 22 with a lower hole having a vent hole 22A and a partition plate 23 with an upper hole having a vent hole 23A are provided in the proximal end side cylindrical portion 21A of the respiratory tube 21. Are provided at intervals in the length direction of the base end side cylindrical portion 21A. In addition, the partition plate 22 with the lower hole and the partition plate 23 with the upper hole are arranged so that the vent hole 22A and the vent hole 23A do not overlap in the length direction of the respiratory tube 21.

  Thereby, even when a part of the urea water tries to enter the base end side cylindrical portion 21A through the base end side opening end 21C of the respiratory tube 21, the infiltration of urea water is blocked by the partition plate 22 with the lower hole. be able to. Further, even when part of the urea water passes through the vent hole 22A of the partition plate 22 with the lower hole, the urea water is separated by the partition plate 23 with the upper hole disposed above the partition plate 22 with the lower hole. Can be blocked. As a result, the urea water can be prevented from leaking to the outside from the distal end side opening end 21D of the respiratory tube 21, and the urea water stored in the urea water tank 14 can be prevented from being reduced at an early stage.

  Next, FIGS. 7 to 9 show a second embodiment of the present invention. The feature of the second embodiment resides in that a plurality of partition plates that form a passage through which gas flows between the inner peripheral surface of the respiratory duct and the barrier section provided inside the respiratory duct are used. . In the present embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  In FIG. 7, reference numeral 31 denotes a respiratory tube attached to the lid 14E of the urea water tank 14, and the respiratory tube 31 is used in this embodiment instead of the respiratory tube 21 according to the first embodiment. It is. Although the respiratory tube 31 is configured in substantially the same manner as the respiratory tube 21 according to the first embodiment, the configuration of each of the partition plates 32 and 34 described later provided in the respiratory tube 31 is the same as that of the first embodiment. It is different from each of the partition plates 22 and 23 with holes.

  Here, the respiratory tube 31 is formed of a cylindrical body (pipe body) bent in an L shape as a whole, almost the same as the respiratory tube 21 according to the first embodiment, and extends from the inside of the urea water tank 14 to the outside. A proximal end cylindrical portion 31A extending upward and downward, and a distal end side cylindrical portion 31B bent from the upper end side of the proximal end cylindrical portion 31A and extending outside the urea water tank 14 in the horizontal direction. Yes. The end portion of the base end side cylindrical portion 31 </ b> A becomes a base end side opening end 31 </ b> C that opens to the inside of the urea water tank 14, and the end portion of the front end side cylindrical portion 31 </ b> B opens to the outside of the urea water tank 14. It is the end 31D.

  Reference numeral 32 denotes a lower partition plate as a barrier portion provided in the proximal end cylindrical portion 31A constituting the respiratory tube 31, and the lower partition plate 32 is disposed above the proximal end opening end 31C. Has been. As shown in FIGS. 7 and 8, the lower partition plate 32 is formed in a semicircular flat plate shape having an outer diameter that is equal to the inner diameter of the inner peripheral surface 31A1 of the proximal end cylindrical portion 31A. The lower partition plate 32 is fixed to the inner peripheral surface 31A1 of the base end side cylindrical portion 31A using means such as adhesion and welding. As a result, a lower passage 33 is formed between the lower partition plate 32 and the inner peripheral surface 31A1 of the base end side cylindrical portion 31A. The lower passage 33 is a semicircular gap having the same shape as the lower partition plate 32. Yes.

  Accordingly, even when a part of the urea water stored in the urea water tank 14 tries to enter the proximal end side cylindrical portion 31A through the proximal end side open end 31C of the respiratory tube 31, the lower partition plate 32 causes the urea to flow. It has a configuration that can block the ingress of water. On the other hand, the lower passage 33 formed between the lower partition plate 32 and the base end side cylindrical portion 31 </ b> A allows gas to flow between the inside and outside of the urea water tank 14, and the inside of the urea water tank 14. Adjust pressure.

  Reference numeral 34 denotes an upper partition plate as a barrier portion provided at a position different from the lower partition plate 32 in the longitudinal direction of the respiratory tube 31, and the upper partition plate 34 is positioned above the lower partition plate 32. The base end side cylindrical portion 31A is provided. The upper partition plate 34 is formed in a semicircular flat plate shape having the same shape as the lower partition plate 32, and is fixed to the inner peripheral surface 31A1 of the base end side cylindrical portion 31A using means such as adhesion and welding. . As a result, an upper passage 35 is formed between the upper partition plate 34 and the inner peripheral surface 31A1 of the base end side cylindrical portion 31A. The upper passage 35 is a semicircular gap having the same shape as the upper partition plate 34. On the other hand, the upper passage 35 formed between the upper partition plate 34 and the base end side cylindrical portion 31A allows gas to flow between the inside and the outside of the urea water tank 14 so that the pressure in the urea water tank 14 is increased. adjust.

  In this case, as shown in FIGS. 8 and 9, the lower partition plate 32 and the upper partition plate 34 are arranged at positions shifted from each other by 180 degrees with respect to the center of the base end side cylindrical portion 31A. That is, the two lower partition plates 32 and the upper partition plate 34 adjacent to each other include a lower passage 33 and an upper passage 35 formed between the inner peripheral surface 31A1 of the base end side cylindrical portion 31A. They are arranged so as not to overlap in the length direction of 31.

  The hydraulic excavator 1 according to the second embodiment is provided with the lower partition plate 32 and the upper partition plate 34 as described above in the respiratory tube 31, and a part of the urea water stored in the urea water tank 14. However, even when trying to enter the base end side cylindrical portion 31A through the base end side open end 31C of the respiratory tube 31, the lower partition plate 32 can block the ingress of urea water. Even when a part of the urea water passes through the lower passage 33 formed between the lower partition plate 32 and the base end side cylindrical portion 31 </ b> A, the urea water is placed on the upper side of the lower partition plate 32. It can be blocked by the upper partition plate 34 arranged. As a result, it is possible to suppress the urea water from leaking outside from the distal end side opening end 31D of the respiratory tube 31.

  Next, FIGS. 10 to 13 show a third embodiment of the present invention. The feature of the third embodiment resides in that a plurality of recessed portions in which the outer peripheral surface of the respiratory tube is recessed toward the inside are used as the barrier portion provided inside the respiratory tube. In the present embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  In FIG. 10, reference numeral 41 denotes a respiratory tube attached to the lid body 14E of the urea water tank 14, and the respiratory tube 41 is used in this embodiment instead of the respiratory tube 21 according to the first embodiment. Thus, the configuration in which the outer peripheral surface of the respiratory tube 41 is recessed to form the respective recessed portions 42 and 44 described later is different from the respiratory tube 21 according to the first embodiment.

  Here, the respiratory tube 41 is formed of a cylindrical body (pipe body) bent in an L shape as a whole, and includes a proximal end side cylindrical portion 41A that extends upward and downward from the inside of the urea water tank 14 to the outside. The distal end side cylindrical portion 41B is bent from the upper end side of the proximal end side cylindrical portion 41A and extends outside the urea water tank 14 in the horizontal direction. The end portion of the base end side cylindrical portion 41 </ b> A becomes a base end side open end 41 </ b> C that opens to the inside of the urea water tank 14, and the end portion of the front end side cylindrical portion 41 </ b> B opens to the outside of the urea water tank 14. It is an end 41D. A lower concave portion 42 and an upper concave portion 44 which will be described later are provided inside the base end side cylindrical portion 41A.

  Reference numeral 42 denotes a lower concave portion as a barrier portion provided in the proximal end cylindrical portion 41A constituting the respiratory tube 41, and the lower concave portion 42 is located above the proximal end opening end 41C. Is arranged. The lower concave portion 42 is depressed toward the inside of the base end side cylindrical portion 41A by pressing the outer peripheral surface 41A1 of the base end side cylindrical portion 41A in the radial direction using, for example, a wedge-shaped member 46 shown in FIG. It is formed by.

  Accordingly, the lower recessed portion 42 has a wedge-shaped cross-sectional shape and protrudes from the outer peripheral surface 41A1 of the proximal end side cylindrical portion 41A, and the upper surface 42A of the lower recessed portion 42 is formed inside the proximal end side cylindrical portion 41A. It is an inclined surface inclined obliquely downward toward (center). Further, a lower passage through which gas flows between the inside and the outside of the urea water tank 14 between the protruding end portion 42B of the lower recessed portion 42 and the inner peripheral surface 41A2 of the proximal end side cylindrical portion 41A. 43 is formed.

  Reference numeral 44 denotes an upper concave portion as a barrier portion provided at a position different from the lower concave portion 42 in the length direction of the respiratory tube 41, and the upper concave portion 44 is more than the lower concave portion 42. Is also located on the upper side and is provided in the base end side cylindrical portion 41A. Similarly to the lower concave portion 42, the upper concave portion 44 is also formed by recessing the outer peripheral surface 41A1 of the proximal end side cylindrical portion 41A inward using a wedge-shaped member 46 (see FIG. 13). ).

  Accordingly, the upper concave portion 44 has a wedge-shaped cross-sectional shape and protrudes from the outer peripheral surface 41A1 of the base end side cylindrical portion 41A to the inside, and the upper surface 44A of the upper concave portion 44 is formed inside the base end side cylindrical portion 41A (center ) Toward the surface). Further, an upper passage 45 that allows gas to flow between the inside and the outside of the urea water tank 14 is provided between the protruding end portion 44B of the upper recessed portion 44 and the inner peripheral surface 41A2 of the proximal end side cylindrical portion 41A. Is formed.

  In this case, as shown in FIGS. 11 and 12, the lower concave portion 42 and the upper concave portion 44 are arranged at positions shifted from each other by 180 degrees with respect to the center of the base end side cylindrical portion 41A. . That is, two adjacent lower concave portions 42 and upper concave portions 44 are formed by a lower passage 43 and an upper passage 45 formed between the inner peripheral surface 41A2 of the base end side cylindrical portion 41A. It arrange | positions in the state which does not overlap in the length direction of the respiratory tract 41.

  The hydraulic excavator 1 according to the third embodiment is provided with the lower concave portion 42 and the upper concave portion 44 as described above in the respiratory tube 41, and the urea water stored in the urea water tank 14 is provided. Even when a part of the breathing tube 41 tries to enter the proximal cylindrical portion 41A through the proximal opening end 41C of the respiratory tube 41, the intrusion of urea water can be blocked by the lower recessed portion 42. Even when a part of the urea water passes through the lower passage 43 formed between the lower concave portion 42 and the base end side cylindrical portion 41 </ b> A, the urea water is passed through the lower concave portion 42. It can interrupt | block by the upper side recessed part 44 arrange | positioned above. As a result, it is possible to suppress the urea water from leaking outside from the distal end side open end 41D of the respiratory tube 41.

  On the other hand, when the urea water tank 14 vibrates greatly, a part of the urea water passes through the lower passage 43 formed between the lower concave portion 42 and the base end side cylindrical portion 41A, or There may be a case where an upper passage 45 formed between the upper concave portion 44 and the base end side cylindrical portion 41A is passed.

  On the other hand, in the third embodiment, the upper surface 42A of the lower concave portion 42 and the upper surface 44A of the upper concave portion 44 are inclined obliquely downward toward the inside of the base end side cylindrical portion 41A, respectively. It is an inclined surface. For this reason, even if a part of the urea water passes through the lower passage 43 and the upper passage 45 due to the great vibration of the urea water tank 14, the lower passage 43 is reduced after the vibration of the urea water tank 14 has subsided. The urea water that has passed through the upper passage 45 can be returned into the urea water tank 14 along the upper surface 44A of the upper concave portion 44 and the upper surface 42A of the lower concave portion 42.

  In addition, the lower concave portion 42 and the upper concave portion 44 are easily formed by recessing the outer peripheral surface 41A1 of the proximal end side cylindrical portion 41A constituting the respiratory tube 41 toward the inside of the proximal end side cylindrical portion 41A. Can be formed. Therefore, compared with the structure which attaches the barrier part which consists of a member different from the respiratory tube 41 to the inner peripheral side of the respiratory tube 41, the structure of the whole respiratory tube 41 can be simplified and it contributes also to reduction of manufacturing cost. can do.

  In the first embodiment described above, two perforated partition plates, that is, a partition plate 22 with a lower hole and a partition plate 23 with an upper hole are provided in the proximal cylindrical portion 21A of the respiratory tube 21. The case is shown as an example. However, the present invention is not limited to this. For example, as in the first modification shown in FIG. 14, three partition wall plates 47 with holes may be provided in the base end side cylindrical portion 21 </ b> A. Further, as in the second modification shown in FIG. 15, four partition wall plates 47 with holes may be provided in the base end side cylindrical portion 21 </ b> A, and further, five or more partition wall plates with holes may be provided. It is good. The same applies to the partition plates 32 and 34 according to the second embodiment and the recessed portions 42 and 44 according to the third embodiment.

  Further, in each of the above-described embodiments, the exhaust gas purification device 12 is configured by the particulate matter removal filter 12C, the urea selective reduction catalyst 12D, and the oxidation catalyst 12E housed in the single cylindrical case 12A. Illustrated. However, the present invention is not limited to this. For example, the present invention may be configured as a NOx purification device including the urea selective reduction catalyst 12D and the oxidation catalyst 12E.

  Further, instead of housing the particulate matter removal filter 12C, the urea selective reduction catalyst 12D, and the oxidation catalyst 12E in a single tubular case 12A, for example, a tubular case containing the particulate matter removal filter 12C, and urea The exhaust gas purification device may be configured by connecting the selective reduction catalyst 12D and the cylindrical case containing the oxidation catalyst 12E.

  Further, in each of the above-described embodiments, the crawler hydraulic excavator 1 is described as an example of the construction machine. However, the present invention is not limited to this, and may be applied to a wheel-type hydraulic excavator. Besides, it can be widely applied to other construction machines such as wheel loaders and hydraulic cranes.

2 Lower traveling body (car body)
3 Upper swing body (car body)
9 Engine 10 Exhaust pipe 12 Exhaust gas purification device 12D Urea selective reduction catalyst 14 Urea water tank 21, 31, 41 Breathing pipe 21C, 31C, 41C Base end side open end 21D, 31D, 41D Front end side open end 22 With lower hole Bulkhead plate (barrier part)
22A, 23A Ventilation hole 23 Bulkhead plate with upper hole (barrier part)
31A1, 41A2 Inner peripheral surface 32 Lower partition plate (barrier part)
33, 43 Lower passage 34 Upper partition plate (barrier part)
35, 45 Upper passage 41A1 Outer peripheral surface 42 Lower recessed portion 44 Upper recessed portion 47 Partition plate with holes

Claims (5)

A self-propelled vehicle body, an engine mounted on the vehicle body, an exhaust gas purification device provided with a urea selective reduction catalyst provided in an exhaust pipe of the engine for removing nitrogen oxides in the exhaust gas, and the exhaust gas A urea water tank comprising a urea water injection valve that is provided in the purification device and injects urea water as a reducing agent to the upstream side of the urea selective reduction catalyst, and a hollow container that stores the urea water supplied to the urea water injection valve And a base end side provided in the urea water tank opens to the inside of the urea water tank and a tip end side opens to the outside of the urea water tank, and gas flows between the inside and outside of the urea water tank. In a construction machine comprising a breathing tube that allows
In order to prevent urea water in the urea water tank from leaking to the outside through the distal end side of the respiratory tube due to vibration of the vehicle body, a barrier having a part of the respiratory tube as a narrow passage is provided inside the respiratory tube. Construction machine characterized in that it is configured to provide a part.   The construction machine according to claim 1, wherein a plurality of the barrier portions are provided at different positions in the length direction of the respiratory tract.   The barrier portion includes a plurality of perforated partition plates attached to an inner peripheral surface on the proximal end side of the breathing tube, through which a gas circulation hole is formed, and adjacent to each of the perforated partition plates. The construction machine according to claim 1 or 2, wherein the two partition walls with holes are arranged so that the vent holes do not overlap in the length direction of the respiratory tract.   The barrier portion is constituted by a plurality of partition plates that are attached in a state in which a passage through which gas flows is formed between the inner peripheral surface on the proximal end side of the respiratory tract and the inner peripheral surface. The adjacent two partition plates are arranged so that the passage between the inner peripheral surface of the respiratory tract is not overlapped in the length direction of the respiratory tract. Construction machinery.   The barrier portion includes a plurality of recesses forming a passage through which a gas flows between the inner peripheral surface of the respiratory tube by denting the outer peripheral surface of the proximal end side of the respiratory tube toward the inside of the respiratory tube. Consists of recesses, and two adjacent recesses among these recesses are such that the passage between the inner periphery of the respiratory tract does not overlap in the length direction of the respiratory tract The construction machine according to claim 1 or 2, wherein the construction machine is arranged.

Images