JP6071855B2 - Construction machinery - Google Patents

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 in exhaust gas.

  In general, a hydraulic excavator as a construction machine is provided with a self-propelled lower traveling body, an upper revolving body mounted on the lower traveling body so as to be capable of swiveling, and an upside-down movable structure at a front portion of the upper revolving body. And a working device.

  The upper revolving structure includes a revolving frame that forms a support structure with a center frame and a side frame, an engine that is mounted horizontally on the rear side of the revolving frame and extends left and right, and left and right directions. A hydraulic pump disposed on one side of the engine, and a fuel tank that is disposed on the front side of the engine and the hydraulic pump and that stores fuel supplied to the engine. It consists of

  A diesel engine is used as an engine of the hydraulic excavator. This diesel engine is said to emit a large amount of nitrogen oxides (hereinafter referred to as NOx). Therefore, there is a NOx purification device for purifying NOx as a post-treatment device for exhaust gas of a diesel engine. This NOx purification device includes, for example, a urea selective reduction catalyst provided in the middle of an exhaust pipe of an engine for removing nitrogen oxides contained in exhaust gas, and an upstream of the urea selective reduction catalyst in the exhaust gas flow direction. And a urea water injection valve that injects urea water as a reducing agent into the exhaust gas that is located on the side and flows through the exhaust pipe.

  The hydraulic excavator includes a urea water tank for storing urea water, a urea water pump for supplying the urea water stored in the urea water tank to the urea water injection valve of the NOx purification device, and the urea A water tank, a urea water pump, and a pipe line connecting the urea water injection valve are provided.

  Here, the urea water tank is configured to be arranged at various locations on the revolving frame such as the inside of the engine room, the vicinity of the hydraulic pump and the hydraulic oil tank, and the like (see, for example, Patent Document 1 and Patent Document 2). In addition, there is a configuration in which a step is formed in the fuel tank to form a space, a urea water tank is disposed in the space, and the urea water is held at an appropriate temperature (for example, Patent Document 3 and Patent Document 4). reference).

JP 2003-20936 A JP 2011-247232 A JP 2011-64132 A JP 2011-63988 A

  By the way, the urea water tank is desired to have a large capacity in order to reduce the number of times of supplying the urea water. However, since many devices are mounted on the hydraulic excavator, it is difficult to secure a space for installing a sufficiently large urea water tank in Patent Documents 1 to 4 described above. In particular, a hydraulic excavator called a small turning type suitable for work on a narrow work site is downsized so that the upper turning body can turn substantially within the vehicle width of the lower traveling body. Therefore, the small-swivel hydraulic excavator has a problem that a space on the swing frame is small and it is more difficult to install a urea water tank having a sufficient capacity. Moreover, for example, if a urea water tank is disposed in the vicinity of a heat source such as an engine, the temperature of the urea water may increase due to heat released from the engine, and the urea water may deteriorate.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a construction machine capable of installing a urea water tank having a sufficient capacity.

  A construction machine according to the present invention includes a self-propelled lower traveling body, an upper revolving body mounted on the lower traveling body so as to be capable of swiveling, and a working device provided on a front portion of the upper revolving body so as to be able to move up and down The upper revolving structure includes a revolving frame that forms a support structure with a center frame and a side frame, and an engine mounted in a horizontally installed state extending leftward and rightward on the rear side of the revolving frame. A hydraulic pump provided in the engine located on one side of the left and right directions, and a fuel provided in the swivel frame located in front of the engine and the hydraulic pump and supplied to the engine A fuel tank, a NOx purification device having a urea selective reduction catalyst and a urea water injection valve provided in the exhaust pipe of the engine for removing nitrogen oxides contained in the exhaust gas, and the urea water injection Comprising a urea water tank to store the urea water supplied toward the valve.

In order to solve the above-mentioned problem, the feature of the configuration adopted by the invention of claim 1 is that the fuel tank has a rectangular bottom plate and a rising height dimension from an inner edge in the left and right directions of the bottom plate. A long plate, a short plate that is opposed to the inner edge of the bottom plate and rises from the left and right outer edges, and is shorter than the height of the long plate, and the long plate, Two side surfaces facing in the front and rear directions are formed between the short plate and the middle of the long plate and the short plate are cut into an L shape so that a long side plate portion and a short side plate portion are formed. Covers the upper ends of the pair of front and rear L-shaped side plates, the long plate, the short plate, and the pair of L-shaped side plates, and is the same as the upper ends of the long plate and the long side plate portion. A high surface portion at a height position, a low surface portion at the same height position as an upper end of the short plate and the short side plate portion, and the high surface portion and the The urea water tank is formed on the vertical surface portion between the high surface portion and the low surface portion of the stepped upper plate. And a vertical tank portion extending upward and downward , and a horizontal tank portion extending laterally from the upper portion of the vertical tank portion toward the left and right sides toward the upper surface. By arranging the fuel tank on the revolving frame so that the short plate faces the outside of the upper revolving body, the vertical tank portion of the urea water tank is formed as the upper revolving body. It is to be arranged facing the outside .

According to the invention of claim 2, the fuel tank is configured such that the short plate is adjacent to the outside by disposing the left and right outer edges of the bottom plate on the side frame side of the swivel frame, The vertical tank portion of the urea water tank is configured to be adjacent to the outside by being disposed closer to the side frame than the vertical surface portion of the stepped upper plate.

  According to the invention of claim 3, the vertical surface portion of the stepped upper plate forming the fuel tank is formed to be inclined from the high surface portion toward the low surface portion, and the vertical tank portion of the urea water tank Is that the inner side surface facing the vertical surface portion and the outer surface facing the inner side surface are inclined by being parallel to the vertical surface portion.

  According to a fourth aspect of the present invention, the high surface portion of the stepped upper plate forming the fuel tank is provided with a fuel supply port for supplying fuel into the fuel tank, and the horizontal tank portion of the urea water tank. In other words, a notch for avoiding the fuel filler opening is formed.

  According to the invention of claim 5, in the urea water tank, a liquid level gauge that extends upward and downward in the vertical tank portion and measures the amount of the urea water in the urea water tank, and the liquid There is a configuration in which a urea water heating member is provided that extends laterally from the lower end of the surface meter and heats the urea water.

According to the first aspect of the present invention, the fuel tank includes a rectangular bottom plate, a long plate having a long rising height from the left and right inner edges of the bottom plate, and the inner end of the bottom plate. Opposite the edge, rising from the outer edge of the left and right direction, a short plate shorter than the length of the long plate, and facing the front and rear direction between the long plate and the short plate It has a pair of L-shaped side plates before and after forming two side surfaces, and a stepped upper plate composed of a high surface portion, a low surface portion, and a vertical surface portion. On the other hand, the urea water tank has a vertical tank portion extending upward and downward along the vertical surface portion between the high surface portion and the low surface portion, and left and right from the upper portion of the vertical tank portion toward the high surface portion. It is formed in an inverted L shape by a horizontal tank portion extending laterally inward in the direction . Therefore, the vertical tank portion can be arranged using a part of the space where the fuel tank is provided. As a result, the height of the urea water tank can be kept low while increasing the capacity by the amount of the vertical tank portion. Further, since the vertical tank portion is formed long in the upward and downward directions, the liquid level in the urea water tank can be maintained at a high position even when there is little remaining urea water. As a result, the liquid level in the urea water tank can be maintained at a high position even when the vehicle body is tilted when there is little remaining urea water.

On the other hand, the urea water tank is provided with a horizontal tank portion on the upper side of the vertical tank portion, so that the capacity can be expanded by the horizontal tank portion. Moreover, by providing the horizontal tank portion, the surface area of the urea water can be increased in a state where the urea water is filled. As a result, even when the urea water freezes and the volume increases, the upward swell can be suppressed small, so that the urea water tank can be prevented from being damaged. Moreover, by arranging the vertical tank portion of the urea water tank so as to face the outside of the upper swing body, the urea water tank efficiently releases the heat of the urea water returned from the engine side to the outside. And the urea water can be maintained within an appropriate temperature. As a result, the lifetime of the urea water can be extended, and the reliability of the NOx purification device can be improved.

  According to the second aspect of the present invention, the vertical tank portion of the urea water tank is made adjacent to the outside by adjoining the short plate of the fuel tank to the outside. Thereby, the urea water tank can efficiently release the heat of the urea water heated and returned from the engine side to the outside, and can maintain the urea water within an appropriate temperature. As a result, the lifetime of the urea water can be extended, and the reliability of the NOx purification device can be improved.

  According to the invention of claim 3, the vertical surface portion of the stepped upper plate of the fuel tank and the inner surface and the outer surface of the vertical tank portion of the urea water tank are arranged in parallel. Thereby, since the urea water tank is arranged without a gap along the stepped upper plate, the fuel tank and the urea water tank can be closely adhered without any gap, and the tank capacity of both can be expanded.

  According to the invention of claim 4, since the horizontal tank portion of the urea water tank is provided with the notch portion, even when this horizontal tank portion is provided on the high surface portion constituting the fuel tank, the refueling of the high surface portion is performed. You can avoid the mouth. Thereby, a capacity | capacitance can be increased by a horizontal tank part. Even if the urea water tank is arranged on the upper surface side of the fuel tank, the fuel can be supplied (supplemented) to the fuel tank without being obstructed by the urea water tank.

  According to the invention of claim 5, the liquid level gauge is configured to extend upward and downward in the vertical tank portion where the liquid level fluctuation of the urea water is small. Thereby, even when working on an inclined land, the measurement error of the amount of urea water can be reduced. Moreover, the urea water heating member extended in the horizontal direction is provided in the lower end edge of the liquid level gauge. Thereby, even when urea water freezes in a cold district, frozen urea water can be thawed.

1 is a front view showing a hydraulic excavator according to an embodiment of the present invention. It is a perspective view which expands and shows the hydraulic excavator which abbreviate | omitted the working device from the right rear side. It is a top view which expands and shows an upper revolving body in the state which omitted the exterior cover. It is a top view which shows the turning frame single-piece | unit in FIG. It is a perspective view which shows the upper turning body which abbreviate | omitted the counterweight and the exterior cover from the right rear side. It is a perspective view which expands and shows a fuel tank, a urea water tank, and a heat insulating material from the right front side. It is a disassembled perspective view which decomposes | disassembles and shows a fuel tank, a urea water tank, and a heat insulating material. It is a front view which shows a fuel tank, a urea water tank, a heat insulating material, and a urea water tank cover. It is a partially broken side view showing a fuel tank, a urea water tank, a heat insulating material, a liquid level gauge, a heater and the like. It is an expanded sectional view which shows the inside of a post-processing unit.

  Hereinafter, as a representative example of a construction machine according to an embodiment of the present invention, a small-swivel hydraulic excavator equipped with a cab will be described as an example and described in detail with reference to FIGS.

  In FIG. 1, reference numeral 1 denotes a crawler hydraulic excavator as a construction machine. The hydraulic excavator 1 includes a self-propelled crawler-type lower traveling body 2, an upper revolving body 4 that is mounted on the lower traveling body 2 via a revolving device 3 so as to be able to swivel, and the upper revolving body 4. It is configured by a working device 5 that is provided on the front side in the front and rear directions so as to be able to move up and down and that performs excavation work of earth and sand.

  The turning device 3 includes a turning wheel 3A (see FIG. 1) provided as a large-diameter bearing structure between the lower traveling body 2 and the upper turning body 4 (the turning frame 6), and the turning wheel 3A as a turning center. And a turning motor 3B (see FIG. 3) for driving the upper turning body 4 to turn. A center joint 3 </ b> C for circulating pressure oil between the lower traveling body 2 and the upper rotating body 4 is disposed at the center of the turning wheel 3 </ b> A.

  A revolving frame 6 forms a support structure for the upper revolving structure 4. As shown in FIG. 4, the swivel frame 6 is provided with a bottom plate 6A made of a thick steel plate or the like extending in the front and rear directions, and standing on the bottom plate 6A. A left vertical plate 6B and a right vertical plate 6C extending in the rear direction, and a left side frame 6D and a right side frame 6E arranged in the left and right directions of the vertical plates 6B and 6C with an interval and extending in the front and rear directions. And a protruding beam 6F that protrudes left and right from the bottom plate 6A and the respective vertical plates 6B and 6C, and supports the left and right side frames 6D and 6E at the front end portions thereof.

  Here, the bottom plate 6 </ b> A and the left and right vertical plates 6 </ b> B and 6 </ b> C constitute a center frame of the revolving frame 6. The bottom plate 6A and the vertical plates 6B and 6C constituting the center frame are arranged on the inner side in the left and right directions of the revolving frame 6, that is, at the center position. On the other hand, the left and right side frames 6 </ b> D and 6 </ b> E are disposed outside the revolving frame 6 in the left and right directions.

  A plurality of, for example, four engine brackets 6G are provided on the rear side of the revolving frame 6 between the left and right vertical plates 6B and 6C. These engine brackets 6G support the engine 8 via an anti-vibration mount 8D described later. Further, the working device 5 is attached to the front side of the left and right vertical plates 6B and 6C so as to be able to move up and down, and a counterweight 7 described later is attached to the rear part.

  Reference numeral 7 denotes a counterweight attached to the rear portion of the swing frame 6 (see FIG. 3). The counterweight 7 is in a weight balance with the work device 5, and is formed as a heavy object having an arc shape. The counterweight 7 is arranged so that the rear side of the upper turning body 4 is substantially within the vehicle width of the lower traveling body 2 even during the turning operation.

  Reference numeral 8 denotes an engine that is located on the front side of the counterweight 7 and is provided on the rear side of the revolving frame 6. The engine 8 is mounted in a horizontally placed state extending in the left and right directions. On the left side of the engine 8, a cooling fan 8 </ b> A (see FIG. 5) for supplying cooling air to a heat exchange device 9 described later is provided. On the other hand, the right side of the engine 8 is a pump mounting portion 8B in which a plurality of female screw holes (not shown) are provided on an annular end surface. The pump mounting portion 8B includes a mounting flange of a hydraulic pump 10 to be described later. A mounting base 22 constituting a mounting base for 10A and the post-processing unit 21 is bolted. Further, an exhaust port (not shown) for exhaust gas exhaust is provided in the upper part on the front side of the engine 8, and an inlet side of an exhaust pipe 20 described later is attached to this exhaust port in a communicating state. .

  The engine 8 has four mounting legs 8C at intervals in the front, rear, left, and right directions so as to correspond to the engine brackets 6G of the revolving frame 6, and the mounting legs 8C are vibration-proof mounts. It is attached to each engine bracket 6G via 8D in a vibration-proof state.

  Reference numeral 9 denotes a heat exchange device provided on the left rear side of the revolving frame 6 so as to face the cooling fan 8A of the engine 8. This heat exchanging device 9 cools various fluids whose temperature has risen with cooling air. The heat exchange device 9 includes a radiator 9B, an oil cooler, an intercooler, and the like (all not shown) in the support frame 9A.

  A hydraulic pump 10 is located on the right side of the engine 8 and is attached to a pump attachment portion 8B of the engine 8. The hydraulic pump 10 is driven by the engine 8 to discharge hydraulic oil supplied from a hydraulic oil tank 11 described later to a control valve device (not shown) as pressure oil. The hydraulic pump 10 is provided with a mounting flange 10A by expanding the end portion on the engine 8 side in a circular shape. A plurality of bolt insertion holes (not shown) are provided on the outer peripheral side of the mounting flange 10A.

  The hydraulic pump 10 has the mounting flange 10A facing the pump mounting portion 8B of the engine 8, and a bolt (not shown) is inserted into each bolt insertion hole, and each bolt is inserted into each female screw hole of the pump mounting portion 8B. Is attached to the pump mounting portion 8B. On the other hand, among the bolts for attaching the hydraulic pump 10 to the engine 8, a plurality of bolts positioned on the upper side are also used when the attachment base 22 is attached to the engine 8.

  A hydraulic oil tank 11 is provided on the revolving frame 6 so as to be located on the revolving center side (working device side) on the front side of the hydraulic pump 10. The hydraulic oil tank 11 stores hydraulic oil for driving the actuators provided in the lower traveling body 2, the turning device 3, and the work device 5. For this purpose, the hydraulic oil tank 11 is formed as a rectangular parallelepiped container that is long in the upward and downward directions, and is disposed inside the left and right directions on the left side of the fuel tank 12 described later.

  Next, the fuel tank 12 used in the present embodiment will be described.

  A fuel tank 12 is provided on the revolving frame 6 so as to be located in front of the engine 8 and the hydraulic pump 10. Specifically, the fuel tank 12 is provided on the revolving frame 6 so as to be arranged on the left and right sides (right side) on the right side frame 6E side with respect to the hydraulic oil tank 11. The fuel tank 12 stores fuel supplied to the engine 8. Here, the right side position of the hydraulic oil tank 11 in which the fuel tank 12 is disposed is located outside in the left and right directions and exposed to the outside. Thereby, the fuel tank 12 can discharge | release the heat | fever of the fuel returned in a warm state efficiently by touching external air. The fuel tank 12 includes a bottom plate 13, a long plate 14, a short plate 15, a front L-shaped side plate 16, a rear L-shaped side plate 17, and a stepped upper plate 18, as shown in FIGS. It is configured in a box shape.

  Reference numeral 13 denotes a bottom plate constituting the bottom of the fuel tank 12, and the bottom plate 13 is disposed on the bottom plate 6 </ b> A constituting the center frame of the revolving frame 6, and on each vertical plate 6 </ b> B side (in the left and right directions) A left edge 13A as an edge, a right edge 13B as another edge disposed opposite to the left edge 13A on the right side frame 6E side (on the left and right sides), a left edge 13A and a right edge A front end edge 13C and a rear end edge 13D that connect to 13B are formed in a rectangular shape that is long in the front and rear directions (see FIG. 7).

  Reference numeral 14 denotes a long plate that rises from the left end edge 13A of the bottom plate 13, and the long plate 14 constitutes the left side surface of the fuel tank 12 by extending forward, rearward, upward, and downward. The hydraulic oil tank 11 faces the right side. The long plate 14 has a lower end edge 14A side fixed to the left end edge 13A of the bottom plate 13 by welding or the like, and extends upward from the left end edge 13A. Here, the height dimension H1 of the long plate 14 indicates the height dimension from the bottom plate 13 to the upper end edge 14B of the long plate 14, and this height dimension H1 is the height dimension H2 of the short plate 15 described later. (H1> H2).

  Reference numeral 15 denotes a short plate rising from the right end edge 13B of the bottom plate 13. The short plate 15 constitutes the right side surface of the fuel tank 12 facing the long plate 14 in the left and right directions. That is, the short plate 15 is arranged at a position adjacent to the outside (outside air) by being arranged on the right side frame 6E side. Thereby, since the short board 15 can touch external air, it can discharge | release the heat | fever of the fuel returned in a warmed state efficiently.

  The short plate 15 has its lower end edge 15A side fixed to the right end edge 13B of the bottom plate 13 by welding or the like, and extends upward from the right end edge 13B. Here, the height dimension H2 of the short plate 15 indicates the height dimension from the bottom plate 13 to the upper edge 15B of the short plate 15, and is set lower than the height dimension H1 of the long plate 14 by a dimension ΔH. . A space for installing a vertical tank portion 35 of the urea water tank 34 to be described later is secured by the height difference of the dimension ΔH.

  Further, the short plate 15 forms a part of the right side surface of the upper swing body 4. In this case, the right side surface of the upper swing body 4 has a higher strength than the flat surface, and has an excellent arc surface in terms of design, specifically, the middle portion in the upper and lower directions protrudes outward in the left and right directions. It is formed as a convex arc surface. Accordingly, the short plate 15 is also formed as a convex arc surface.

  Reference numeral 16 denotes a front L-shaped side plate that rises from the front end edge 13 </ b> C of the bottom plate 13. The front L-shaped side plate 16 connects (covers) the front end edge of the long plate 14 and the front end edge of the short plate 15 and constitutes the front surface of the fuel tank 12. The front L-shaped side plate 16 is notched in an L shape in the middle between the long plate 14 and the short plate 15. Accordingly, the front L-shaped side plate 16 has a long side plate portion 16A located on the long plate 14 side (left and right inside) and a short plate located on the short plate 15 side (left and right outside). The side plate portion 16B is integrally formed, and is formed in a substantially L shape as a whole.

  The long side plate portion 16A is formed such that the height dimension from the lower end edge (the front end edge 13C of the bottom plate 13) to the upper end edge 16A1 is the same as the height dimension H1 of the long plate. The left end edge 16A2 of the long side plate portion 16A is fixed to the front end edge of the long plate 14 by welding or the like. On the other hand, a falling edge 16A3 is formed on the long side plate portion 16A so as to fall from the right end of the upper end edge 16A1 toward the short side plate portion 16B. The falling edge 16A3 is inclined outward (right side) from the upper side to the lower side.

  The short side plate portion 16B is formed such that the height dimension from the lower end edge (the front end edge 13C of the bottom plate 13) to the upper end edge 16B1 is the same as the height dimension H2 of the short plate 15. The upper end edge 16B1 of the short side plate portion 16B extends from the lower end edge of the falling end edge 16A3 of the long side plate portion 16A toward the upper end edge 15B of the short plate 15. Further, the right end edge 16B2 of the short side plate portion 16B is formed in a convex arc shape protruding outward along the convex arc-shaped short plate 15, and is fixed to the front end edge of the short plate 15 by welding or the like. .

  As a result, the front L-shaped side plate 16 is stepped at the upper end side portion by the upper end edge 16A1 of the long side plate portion 16A, the falling end edge 16A3 of the long side plate portion 16A, and the upper end edge 16B1 of the short side plate portion 16B. It is formed in a shape.

  Reference numeral 17 denotes a rear L-shaped side plate that rises from the rear end edge 13D of the bottom plate 13. The rear L-shaped side plate 17 faces the front L-shaped side plate 16 in the front and rear directions. The rear L-shaped side plate 17 connects (covers) the rear end edge of the long plate 14 and the rear end edge of the short plate 15, and constitutes the rear surface of the fuel tank 12. As with the front L-shaped side plate 16, the rear L-shaped side plate 17 has an intermediate L-shaped notch between the long plate 14 and the short plate 15, and the long side plate portion 17 </ b> A and the short side plate portion 17 </ b> B are integrated. It is formed and is formed in a substantially L shape as a whole.

  That is, the rear L-shaped side plate 17 is stepped by the upper end edge 17A1 of the long side plate portion 17A, the falling end edge 17A2 of the long side plate portion 17A, and the upper end edge 17B1 of the short side plate portion 17B. The same shape as the front L-shaped side plate 16 is formed. The rear L-shaped side plate 17 is fixed to the rear end edge of the long plate 14 and the rear end edge of the short plate 15 by welding or the like. A pump bracket 17C is provided at the upper position of the long side plate portion 17A (see FIGS. 5 and 9). A urea water pump 19 described later is attached to the pump bracket 17C.

  Reference numeral 18 denotes a stepped upper plate that covers the upper end edges of the long plate 14, the short plate 15, the front L-shaped side plate 16, and the rear L-shaped side plate 17. The stepped upper plate 18 constitutes the upper surface of the fuel tank 12 and is a place for installing a urea water tank 34 to be described later. The stepped upper plate 18 includes a high surface portion 18A located on the upper step, a low surface portion 18B located on the lower step, and a vertical surface portion 18C located on the middle portion in the left and right directions.

  The high surface portion 18 </ b> A is located on the left side (the inner side in the left and right directions) of the stepped upper plate 18 and is formed as a flat plate elongated in the front and rear directions. The high surface portion 18A is provided at the same height as the upper end edge 14B of the long plate 14 and the upper end edges 16A1 and 17A1 of the front and rear long side plate portions 16A and 17A. It constitutes a certain upper surface. The high surface portion 18A is fixed to the upper end edges 16A1, 17A1 of the front and rear long side plate portions 16A, 17A by welding or the like. An oil supply port 18D for supplying fuel is provided at the front side position of the high surface portion 18A so as to protrude upward.

  The low surface portion 18B is located on the right side (left and right outside) of the stepped upper plate 18 and is formed as a flat plate that is long in the front and rear directions. The low surface portion 18B is provided at the same height as the upper end edge 15B of the short plate 15 and the upper end edges 16B1, 17B1 of the short side plate portions 16B, 17B, and constitutes a lower step surface at a low position of the stepped upper plate 18. ing. The low surface portion 18B extends in the front and rear directions so as to be parallel to the high surface portion 18A at a position lower than the high surface portion 18A, and is fixed to the upper end edges 16B1 and 17B1 of the front and rear short side plate portions 16B and 17B by welding or the like. Has been.

  The vertical surface portion 18C connects the high surface portion 18A and the low surface portion 18B, and the vertical surface portion 18C extends from the right end edge 18A1 of the high surface portion 18A toward the left end edge 18B1 of the low surface portion 18B. Yes. Here, as shown in FIGS. 7 and 8, the vertical surface portion 18C is formed at the same angle as the inclination angles of the falling end edges 16A3 and 17A2 of the front and rear long side plate portions 16A and 17A. That is, the vertical surface portion 18C is inclined rightward (leftward and rightward outward) from the right end edge 18A1 of the high surface portion 18A toward the left end edge 18B1 of the low surface portion 18B. In this case, the inclination angle of the vertical surface portion 18C is set to be substantially parallel to the inner side surface 35B and the outer side surface 35C of the vertical tank portion 35 constituting the urea water tank 34 described later.

  Further, the high surface portion 18A and the low surface portion 18B are provided with a total of four screw seats 18E each having a female screw hole 18E1 into which a bolt 38 for attaching a urea water tank 34 to be described later is screwed. Specifically, the two screw seats 18E provided on the high surface portion 18A are disposed on the rear side of the fuel filler port 18D and on the rear end edge side of the high surface portion 18A. On the other hand, the two screw seats 18E provided on the low surface portion 18B are disposed on the front end edge side and the rear end edge side of the low surface portion 18B.

  Reference numeral 19 denotes a urea water pump provided in the fuel tank 12 so as to overhang the hydraulic pump 10. As shown in FIG. 5, the urea water pump 19 is disposed between a urea water tank 34, which will be described later, and a urea water injection valve 27, which will be described later, constituting the NOx purification device. The urea water pump 19 supplies urea water stored in a urea water tank 34 described later to the post-processing unit 21 side provided in the engine 8. The urea water pump 19 is attached to a pump bracket 17 </ b> C provided on the rear L-shaped side plate 17 of the fuel tank 12.

  Reference numeral 20 denotes an exhaust pipe (see FIG. 3) provided in connection with the engine 8. The exhaust pipe 20 discharges exhaust gas discharged from the engine 8 to the outside, and the downstream side is connected to a tail pipe 41G described later. A post-processing unit 21 to be described later is provided in the middle of the exhaust pipe 20.

  Next, in order to process the exhaust gas discharged from the engine 8, the configuration of the post-processing unit 21 provided connected to the exhaust side of the engine 8 will be described.

  Reference numeral 21 denotes an aftertreatment unit provided in the middle of the exhaust pipe 20, and this aftertreatment unit 21 oxidizes carbon monoxide (CO), hydrocarbon (HC), etc. contained in the exhaust gas discharged from the engine 8. Thus, nitrogen oxide (NOx) contained in the exhaust gas is purified, and noise of the exhaust gas is further reduced. The aftertreatment unit 21 is located on the right side of the engine 8 and is provided above the hydraulic pump 10. The aftertreatment unit 21, which will be described later, a first exhaust gas aftertreatment device 23, a connecting pipe 26, a urea water injection valve 27, 2 exhaust gas after-treatment devices 28.

  As shown in FIG. 5, the aftertreatment unit 21 has the attachment base 22 in a state where the first exhaust gas aftertreatment device 23, the connecting pipe 26, and the second exhaust gas aftertreatment device 28 are assembled. 22 is attached to the engine 8 together with the hydraulic pump 10.

  Reference numeral 22 denotes a mounting base that forms a mounting base for the post-processing unit 21. The attachment base 22 is located on the upper side of the hydraulic pump 10 and is attached to the pump attachment portion 8 </ b> B of the engine 8. The attachment base 22 is for fixedly attaching a first exhaust gas aftertreatment device 23 and a second exhaust gas aftertreatment device 28 described later to the engine 8 side. The attachment base 22 can be attached to the pump attachment portion 8B together with the attachment flange 10A of the hydraulic pump 10 (when fastened) when the hydraulic pump 10 is attached to the engine 8, for example.

  Reference numeral 23 denotes a first exhaust gas aftertreatment device that constitutes a part of the aftertreatment unit 21. The first exhaust gas aftertreatment device 23 is provided in the middle of the exhaust pipe 20 connected to the engine 8. The first exhaust gas aftertreatment device 23 includes a cylindrical case 24 extending in the front and rear directions of the upper swing body 4, and an oxidation catalyst 25 (see FIG. 10) disposed in the cylindrical case 24. It is comprised by.

  The cylindrical case 24 is formed as a cylindrical sealed container, and is fixed to the mounting base 22 using a fastening band, a bolt, or the like (all not shown). On the upstream side (front side portion) of the cylindrical case 24, an air supply port 24A (see FIG. 10) made of a tubular body is provided so as to protrude in the radial direction. The air supply port 24A is provided with a large number of through holes (not shown) located in the cylindrical case 24, and exhaust gas passes through each of the through holes to reduce exhaust noise (silence). ) On the other hand, the exhaust pipe 20 is connected to the protruding end side of the air supply port 24A. Further, an exhaust port 24B (see FIG. 10) is provided on the downstream side (rear side portion) of the cylindrical case 24 so as to open in the radial direction.

  The oxidation catalyst 25 disposed in the cylindrical case 24 constitutes one of the processing members that purify the exhaust gas. The oxidation catalyst 25 is made of, for example, a ceramic cell-like cylinder, and a large number of through holes are formed in the axial direction, and the inner surface is coated with a noble metal or the like. The oxidation catalyst 25 oxidizes and removes carbon monoxide (CO), hydrocarbon (HC), etc. contained in the exhaust gas by circulating the exhaust gas through each through hole at a predetermined temperature. It is.

  A connection pipe 26 is connected to the exhaust port of the cylindrical case 24. The connecting pipe 26 is disposed on the outer periphery of the first exhaust gas aftertreatment device 23 so as to extend substantially in parallel with the first exhaust gas aftertreatment device 23. The connection pipe 26 is connected to the exhaust port 24B of the cylindrical case 24 forming the first exhaust gas aftertreatment device 23 on the inlet side, and is connected to the exhaust port 24B of the cylindrical case 29 forming the second exhaust gas aftertreatment device 28 described later on the outlet side. It is connected to the air supply port 29A. Thereby, the connecting pipe 26 can guide the exhaust gas discharged from the first exhaust gas aftertreatment device 23 to the second exhaust gas aftertreatment device 28.

  Reference numeral 27 denotes a urea water injection valve provided in the connection pipe 26. The urea water injection valve 27 constitutes a part of the NOx purification device together with a second exhaust gas aftertreatment device 28 described later. The urea water injection valve 27 is attached to the upstream side of the connection pipe 26, is connected to the urea water pump 19 through a downstream supply pipe 32B of the urea water pipe 32 described later, and urea water through the return pipe 32C. It is connected to the tank 34. The urea water injection valve 27 is for injecting a urea aqueous solution toward the exhaust gas flowing through the connection pipe 26.

  Reference numeral 28 denotes a second exhaust gas aftertreatment device that constitutes a part of the aftertreatment unit 21. The second exhaust gas aftertreatment device 28 is provided on the outlet side of the connecting pipe 26 and is disposed, for example, at a position overlapping the upper side of the first exhaust gas aftertreatment device 23. The second exhaust gas aftertreatment device 28 is substantially the same as the first exhaust gas aftertreatment device 23 described above, and has a cylindrical tubular case 29 and a urea selective reduction catalyst disposed in the tubular case 29. 30 and an oxidation catalyst 31 disposed on the downstream side of the urea selective reduction catalyst 30.

  Here, the second exhaust gas aftertreatment device 28 (cylindrical case 29, urea selective reduction catalyst 30, oxidation catalyst 31) and the urea water injection valve 27 described above are nitrogen in exhaust gas discharged from the engine 8. A NOx purification device for removing oxide (NOx) is configured.

  The cylindrical case 29 is formed as a sealed container by closing both ends of the cylindrical body, and is fixed to the mounting base 22 using a fastening band, a bolt, or the like (all not shown). An air supply port 29 </ b> A is provided in the front portion, which is the upstream side of the cylindrical case 29, so as to open in the radial direction, and the outlet side of the connection pipe 26 is connected to the air supply port 29 </ b> A. On the other hand, an exhaust port 29 </ b> B is provided at a rear portion on the downstream side of the cylindrical case 29 so as to protrude upward in the radial direction. The exhaust port 29B constitutes the downstream side of the exhaust pipe 20, and the protruding end side of the exhaust port 29B is connected to a tail pipe 41G described later. A large number of through holes are provided in the lower portion of the exhaust port 29B, and exhaust gas passes through each of the through holes, whereby exhaust sound is reduced (silenced).

  The urea selective reduction catalyst 30 is made of, for example, a ceramic tubular body made of ceramics. A large number of through holes are formed in the axial direction, and the inner surface is coated with a noble metal. The urea selective reduction catalyst 30 normally causes nitrogen oxide (NOx) contained in the exhaust gas discharged from the engine 8 to selectively undergo a reduction reaction with ammonia generated from the urea aqueous solution, and decomposes into nitrogen and water. Is.

  On the other hand, the oxidation catalyst 31 arranged in the cylindrical case 29 is substantially in the same manner as the oxidation catalyst 25 arranged in the cylindrical case 24 of the first exhaust gas aftertreatment device 23 described above. It consists of a cylinder and has many through-holes formed in the axial direction, and the inner surface is coated with a noble metal. As a result, the oxidation catalyst 31 oxidizes residual ammonia remaining after the nitrogen oxides are reduced by the urea selective reduction catalyst 30 and separates them into nitrogen and water.

  A urea water pipe 32 is provided by connecting a urea water tank 34, a urea water pump 19, and a urea water injection valve 27 constituting the NOx purification device, which will be described later. The urea water conduit 32 allows urea water to flow from a urea water tank 34 described later toward the urea water injection valve 27. Since the urea water pressurized by the urea water pump 19 circulates in the urea water pipe line 32, for example, a pressure-resistant hose having flexibility is used.

  The urea water pipe 32 is an upstream supply pipe 32A that connects a urea water tank 34 (lid body 36L), which will be described later, and the urea water pump 19, and a downstream side that connects the urea water pump 19 and the urea water injection valve 27. The supply line 32 </ b> B and the return line 32 </ b> C connecting the urea water injection valve 27 and the urea water tank 34 (lid body 36 </ b> L) are configured. The upstream supply pipe 32A extends upward and downward in the vertical tank portion 35 at the lower part of the lid body 36L, and the lower end side is a suction port 32A1. Thereby, the suction port 32A1 can suck out urea water even when the remaining amount of urea water in the urea water tank 34 becomes small. The urea water pipe 32 circulates the urea water between the urea water tank 34 and the urea water injection valve 27.

  Reference numeral 33 denotes a heat insulating pipe provided so as to cover a part of the urea water pipe 32, for example, about half of the downstream side supply pipe 32B and the return pipe 32C on the urea water injection valve 27 side. The heat insulating tube 33 is formed, for example, by forming a foamable resin material into a tubular shape. The heat insulation pipe body 33 insulates the urea water flowing through the urea water pipe line 32 so as not to increase in temperature due to heat generated by the engine 8, the hydraulic pump 10, the post-processing unit 21, and the like.

  Next, the urea water tank 34 used in this embodiment will be described.

  A urea water tank 34 is provided above the stepped upper plate 18 of the fuel tank 12. The urea water tank 34 serves as a reducing agent to be supplied into the exhaust gas flowing through the connection pipe 26 on the upstream side of the urea selective reduction catalyst 30 disposed in the cylindrical case 29 of the second exhaust gas aftertreatment device 28. Of urea water. The urea water tank 34 is formed as an inverted L-shaped container by a vertical tank portion 35 and a horizontal tank portion 36.

  Reference numeral 35 denotes a vertical tank portion disposed on the lower surface portion 18 </ b> B of the stepped upper plate 18 constituting the fuel tank 12. The vertical tank portion 35 extends upward and downward along the vertical surface portion 18C between the high surface portion 18A and the low surface portion 18B of the stepped upper plate 18 constituting the fuel tank 12. The vertical tank portion 35 is disposed on the right side frame 6E side (the left and right outer sides) with respect to the vertical surface portion 18C of the stepped upper plate 18 so as to be externally provided via the urea water tank cover 44D. Adjacent to. Thereby, since the vertical tank part 35 is arrange | positioned in the position close | similar to external air, it can discharge | release the heat | fever of the urea water whose temperature rose and can maintain a suitable temperature state. The vertical tank portion 35 includes a deep bottom surface 35A, an inner side surface 35B, an outer side surface 35C, a front surface 35D, and a rear surface 35E.

  For example, the deep bottom surface 35A of the vertical tank portion 35 is formed so that the width dimension (left and right dimension) is substantially the same as the width dimension of the low surface portion 18B, and the length dimension in the front and rear directions is the same as that of the low surface portion 18B. The length is slightly shorter than the length between the screw seats 18E provided on both front and rear ends.

  The inner side surface 35B is formed to rise upward from the left end edge of the deep bottom surface 35A. The inner surface 35B faces the vertical surface portion 18C of the stepped upper plate 18 and is inclined so as to follow the vertical surface portion 18C. On the other hand, the outer surface 35C faces the inner surface 35B by rising upward from the right edge of the deep bottom surface 35A. The outer side surface 35C is inclined so as to be parallel to the inner side surface 35B with an interval in the left and right directions. The outer surface 35C extends upward and downward along an outer panel 44D1 of a urea water tank cover 44D described later.

  Here, as shown in FIG. 8, the outer panel 44D1 of the urea water tank cover 44D is curved and formed in a convex arc shape so as to be continuous with the upper side of the short plate 15 located outside the fuel tank 12. . For this reason, the outer surface 35C of the vertical tank portion 35 is inclined leftward (center frame side) from the lower side toward the upper side along the outer panel 44D1.

  In accordance with this, the inner surface 35B of the vertical tank portion 35 is inclined so as to be parallel to the outer surface 35C. Accordingly, the vertical tank portion 35 of the urea water tank 34 is inclined with the outer surface 35C aligned with the outer panel 44D1. On this, the inner surface 35B and the vertical surface portion 18C of the stepped upper plate 18 constituting the fuel tank 12 are inclined so as to be parallel to the outer surface 35C. Thereby, when the urea water tank 34 is assembled to the fuel tank 12, the inner side surface 35B of the urea water tank 34 and the vertical surface portion 18C of the fuel tank 12 can be brought into close contact with each other without any gap. Therefore, the capacity of the urea water tank 34 and the fuel tank 12 can be efficiently expanded.

  In addition, by arranging the inner side surface 35B and the outer side surface 35C of the vertical tank portion 35 in parallel, the liquid level fluctuation for each unit flow rate when urea water decreases in the vertical tank portion 35 is made constant. Therefore, the remaining amount of urea water can be easily controlled.

  A front surface 35D rising from the front end edge of the deep bottom surface 35A extends to the high surface portion 18A of the fuel tank 12, and connects the front end edge of the inner side surface 35B and the front end edge of the outer side surface 35C. On the other hand, a rear surface 35E that faces the front surface 35D and rises from the rear end edge of the deep bottom surface 35A extends to the high surface portion 18A of the fuel tank 12, and extends between the rear end edge of the inner side surface 35B and the rear end edge of the outer side surface 35C. It is connected. The front surface 35D and the rear surface 35E are formed to face each other in parallel.

  Reference numeral 36 denotes a horizontal tank portion disposed on the high surface portion 18 </ b> A of the stepped upper plate 18 constituting the fuel tank 12. The horizontal tank portion 36 extends laterally (leftward) from the upper portion of the vertical tank portion 35 toward the high surface portion 18A. Thus, the urea water tank 34 is formed in an inverted L shape as a whole by the vertical tank portion 35 and the horizontal tank portion 36. The horizontal tank portion 36 includes a shallow bottom surface 36A, a front inner surface 36B, a rear inner surface 36C, an outer surface 36D, a right front surface 36E, a left front surface 36F, a rear surface 36G, and an upper surface 36H.

  A shallow bottom surface 36A extending to the left from the upper edge of the inner side surface 35B of the vertical tank portion 35 is disposed behind the fuel filler port 18D so as to avoid the fuel filler port 18D. The shallow bottom surface 36A is formed so that its width dimension (left and right dimension) is substantially the same as the width dimension of the high surface portion 18A of the fuel tank 12, and the front and rear length dimensions are both the front and rear ends of the high surface portion 18A. The length is slightly shorter than the length between the screw seats 18E provided on the side.

  The horizontal tank portion 36 is provided with a front inner side surface 36B positioned above the inner side surface 35B of the vertical tank portion 35, and a rear inner side surface 36C that rises upward from the left edge of the shallow bottom surface 36A. ing.

  The outer surface 36D of the horizontal tank portion 36 is connected to the upper portion of the outer surface 35C of the vertical tank portion 35. That is, the outer surface 36D is inclined at the same angle as the outer surface 35C. Thereby, the outer side surface 36D forms the same plane integrally formed with the outer side surface 35C.

  A right front surface 36E of the horizontal tank portion 36 is connected to an upper portion of the front surface 35D of the vertical tank portion 35 and is inclined rearward toward the upper side. The right front surface 36E is provided with a water supply port 36J for supplying urea water to the urea water tank 34. On the other hand, the left front surface 36F that rises upward from the front edge of the shallow bottom surface 36A faces the rear side of the fuel filler opening 18D. Here, on the left front side of the horizontal tank portion 36, a portion surrounded by the front inner side surface 36B and the left front surface 36F is a cutout portion 36K for avoiding the fuel filler opening 18D.

  The rear surface 36G of the horizontal tank portion 36 is formed to rise from the rear end edge of the shallow bottom surface 36A. The upper surface 36H covers the upper portions of the front inner side surface 36B, the rear inner side surface 36C, the outer side surface 36D, the right front surface 36E, the left front surface 36F, and the rear surface 36G. In addition to the upstream supply line 32A and the return line 32C of the urea water line 32, the upper part 36H is connected to a sensor part 39A and a heater 41 of a liquid level gauge 39, which will be described later, at a position above the vertical tank part 35. A lid body 36L to which the lead wire 40 and the like are attached is provided.

  Reference numeral 37 denotes four mounting portions provided in the urea water tank 34. The attachment portion 37 is formed of an L-shaped plate material, and has a through hole 37A in the upward and downward directions. The through-hole 37A is for inserting a bolt 38 for attaching the urea water tank 34 to the fuel tank 12. The attachment portion 37 is disposed on the front surface 35D and the rear surface 35E of the vertical tank portion 35 and on the left front surface 36F and the rear surface 36G of the horizontal tank portion 36 so as to correspond to the screw seats 18E provided in the fuel tank 12. Yes. The urea water tank 34 is attached to the stepped upper plate 18 of the fuel tank 12 by placing the mounting portion 37 on the screw seat 18E and screwing the bolt 38 into the female screw hole 18E1 of the screw seat 18E. .

  Reference numeral 39 denotes a liquid level gauge provided on the lower side of the lid body 36L. The liquid level gauge 39 is connected to a lead wire 40 attached to the lid body 36L, and the amount of urea water in the urea water tank 34 is shown. Is to measure. The liquid level gauge 39 includes a sensor unit 39A and a float 39B. The sensor unit 39A extends in the vertical tank unit 35 upward and downward. The float 39B floats on the liquid level of the urea water and can move upward and downward along the sensor unit 39A in accordance with the fluctuation of the liquid level. Thereby, the sensor unit 39A detects the remaining amount of the urea water in the urea water tank 34 by detecting the position of the float 39B. Further, an upstream supply line 32A of the urea water line 32 is provided below the lid 36L so as to extend upward and downward along the liquid level gauge 39.

  In this case, since the vertical tank portion 35 is formed long in the upward and downward directions, the liquid level in the urea water tank 34 (vertical tank portion 35) is high even when there is little remaining urea water. Can be maintained in position. Thereby, even when working on an inclined land, the suction port 32A1 of the upstream supply pipe 32A can be positioned in the urea water solution, so that the urea water in the urea water tank 34 can be sucked out. As a result, the urea water in the urea water tank 34 can be supplied efficiently.

  Further, the inner surface 35B and the outer surface 35C, and the front surface 35D and the rear surface 35E of the vertical tank portion 35 that face each other are formed in parallel with each other. Thereby, the liquid level fluctuation | variation for every unit flow volume when urea water reduces in the vertical tank part 35 can be made constant, and residual amount control of urea water can be performed easily.

  Reference numeral 41 denotes a heater as a urea water heating member extending in the lateral direction (rearward) from the lower end edge of the liquid level gauge 39. The heater 41 heats the urea water in the urea water tank 34 so that it does not freeze.

  Reference numeral 42 denotes a heat insulating material provided in the urea water tank 34. The heat insulating material 42 prevents heat generated by the fuel tank 12 from being transmitted to the urea water tank 34. For example, the heat insulating material 42 is formed by molding a foamable resin material into a plate shape bent in a crank shape. Yes. The heat insulating material 42 is provided between the urea water tank 34 and the fuel tank 12.

  Reference numeral 43 denotes a cab (see FIGS. 3 and 5) mounted on the left front side of the revolving frame 6. The cab 43 is carried by an operator, in which a driver's seat on which the operator is seated, traveling Operating levers, working operating levers, etc. (both not shown) are provided.

  Reference numeral 44 denotes an exterior cover provided on the revolving frame 6 from the rear side to the side of the cab 43. The exterior cover 44 covers the engine 8, the heat exchange device 9, the hydraulic pump 10, the urea water pump 19, the post-treatment unit 21, the urea water tank 34 and the like mounted on the revolving frame 6. The exterior cover 44 is provided between the cab 43 and the counterweight 7 so as to cover the right front cover 44A provided at the right front portion so as to cover the front side of the fuel tank 12 and the engine 8, the heat exchange device 9, and the like. An engine cover 44B, a left side cover 44C falling from the left side of the engine cover 44B, a urea water tank cover 44D, a urea water pump cover 44E, and a processing device cover 44F as a purification device cover provided separately from these. It is comprised including.

  The urea water tank cover 44 </ b> D covers the urea water tank 34 mounted on the upper side of the fuel tank 12. The urea water tank cover 44D includes an outer panel 44D1 extending upward from the left end edge of the lower surface portion 18B of the fuel tank 12, an upper panel 44D2 extending leftward from the upper end edge of the outer panel 44D1, and the upper panel 44D2. And an inner panel 44D3 that falls from the left end edge toward the left end edge of the high surface portion 18A of the fuel tank 12. The outer panel 44 </ b> D <b> 1 has a curved surface that protrudes rightward (leftward and rightward outward) following the convex arc shape of the short plate 15 of the fuel tank 12. The outer panel 44D1 faces the outer surface 35C and the outer surface 36D of the urea water tank 34.

  The urea water pump cover 44E is positioned behind the urea water tank cover 44D and covers the urea water pump 19. Furthermore, the processing device cover 44F extends forward and rearward on the left side of the urea water tank cover 44D and the urea water pump cover 44E, and covers the second exhaust gas aftertreatment device 28 constituting the NOx purification device. The processing apparatus cover 44F is provided with a tail pipe 44G that protrudes upward from the rear side. The tail tube 44G is connected to the exhaust port 29B of the cylindrical case 29.

  Next, the operation (operation) of the hydraulic excavator 1 to which this embodiment is applied will be described.

  An operator boarding the cab 43 starts the engine 8 and drives the hydraulic pump 10. Thereby, the pressure oil from the hydraulic pump 10 is supplied to various actuators via the control valve device. Thereby, when the operator operates the operation lever for traveling, the lower traveling body 2 can be moved forward or backward. On the other hand, by operating the operation lever for work, the turning device 3 and the work device 5 can be operated to perform excavation work of earth and sand.

  During operation of the engine 8, the exhaust gas discharged from the engine 8 is discharged into the atmosphere through the exhaust pipe 20, the first exhaust gas aftertreatment device 23, the connection pipe 26, and the second exhaust gas aftertreatment device 28. The At this time, the oxidation catalyst 25 provided in the first exhaust gas aftertreatment device 23 oxidizes and removes carbon monoxide (CO), hydrocarbon (HC), etc. contained in the exhaust gas.

  On the other hand, the connecting pipe 26 injects urea water from the urea water injection valve 27 toward the exhaust gas, and the second exhaust gas aftertreatment device 28 decomposes nitrogen oxides into nitrogen and water by the urea selective reduction catalyst 30. To do. Further, the oxidation catalyst 31 oxidizes residual ammonia and separates it into nitrogen and water, whereby the purified exhaust gas is discharged into the atmosphere.

  In this case, the urea water tank that stores the urea water is desired to have a large capacity in order to reduce the number of times of supplying the urea water. However, it is difficult to arrange a urea water tank having a sufficient capacity on a swivel frame where various devices are complicated.

  Therefore, in the present embodiment, the upper surface side of the fuel tank 12 is formed as the stepped upper plate 18 by the high surface portion 18A, the low surface portion 18B, and the vertical surface portion 18C. The urea water tank 34 includes a vertical tank portion 35 extending upward and downward along the vertical surface portion 18C between the high surface portion 18A and the low surface portion 18B, and an upper surface portion 18A from the top of the vertical tank portion 35. It is formed in an inverted L shape by a horizontal tank portion 36 extending laterally upward. Thus, a urea water tank 34 having a sufficient capacity is disposed on the upper surface side of the fuel tank 12.

  Further, the upper surface of the fuel tank 12 is a stepped upper plate 18 and the vertical tank portion 35 is formed in the urea water tank 34, so that, for example, a urea water tank is disposed above the rectangular fuel tank. Thus, the height dimension of the vehicle body (upper swing body 4) of the excavator 1 can be kept low. As a result, the visibility of the operator can be ensured satisfactorily.

  Further, the vertical tank portion 35 can maintain the liquid level in the urea water tank 34 (vertical tank portion 35) at a high position even when there is little remaining urea water. Thereby, even when working on an inclined land, the suction port 32A1 of the upstream supply pipe 32A can be positioned in the urea water solution, so that the urea water in the urea water tank 34 can be sucked out. As a result, the supply failure of urea water can be reduced, and the urea water in the urea water tank 34 can be supplied efficiently.

  Further, the temperature of the urea water may rise due to heat generated by the engine 8, the hydraulic pump 10, the post-processing unit 21, and the like. This urea water is said to begin to deteriorate when it exceeds about 50 ° C.

  Therefore, according to the present embodiment, the fuel tank 12 is arranged so that the short plate 15 is disposed adjacent to the outside of the revolving frame 6 on the right side frame 6E side, so that the vertical tank portion 35 of the urea water tank 34 is disposed. Can be adjacent to the outside via the urea water tank cover 44D. Thereby, since the heat in the urea water tank 34 can be released to the outside, an increase in the temperature of the urea water can be suppressed. As a result, normal urea water maintained at an appropriate temperature that does not deteriorate can be supplied to the NOx purification device, and the life of the urea water can be extended.

  Further, the inner side surface 35B and the outer side surface 35C of the vertical tank portion 35 of the urea water tank 34 and the vertical surface portion 18C of the stepped upper plate 18 of the fuel tank 12 are arranged in parallel. Thereby, since the urea water tank 34 is arrange | positioned without gap with respect to the fuel tank 12, the capacity | capacitance of the urea water tank 34 and the fuel tank 12 can be expanded without waste.

  In addition, by arranging the inner side surface 35B and the outer side surface 35C of the vertical tank portion 35 in parallel, the liquid level fluctuation for each unit flow rate when urea water decreases in the vertical tank portion 35 is made constant. Therefore, the remaining amount of urea water can be easily controlled.

  Further, the horizontal tank portion 36 of the urea water tank 34 is formed with a cutout portion 36K for avoiding the fuel filler port 18D provided in the high surface portion 18A of the fuel tank 12. Thereby, since the horizontal tank part 36 can be arrange | positioned on the high surface part 18A of the fuel tank 12, the capacity | capacitance of a urea water tank can be increased. Further, the fuel can be supplied (supplied) to the fuel tank 12 without being obstructed by the urea water tank 34.

  Further, the liquid level gauge 39 is configured to extend upward and downward in the vertical tank portion 35 where the liquid level fluctuation of the urea water is small. Thereby, even when the vehicle body is tilted, the measurement error of the amount of urea water can be reduced.

  The urea water is solidified at -11 ° C., and the volume of the solidified urea water may expand and damage the urea water tank. However, since the urea water tank 34 is provided with the horizontal tank portion 36 on the upper side of the vertical tank portion 35, the capacity can be expanded by the horizontal tank portion 36. Moreover, by providing the horizontal tank portion 36, the surface area of the urea water can be increased while the urea water is filled. As a result, even when the urea water freezes and the volume increases, the upward swell can be suppressed small, so that the urea water tank 34 can be prevented from being damaged. Further, a heater 41 extending in the lateral direction is provided at the lower end edge of the liquid level gauge 39. Thereby, coagulation of urea water due to a temperature drop can be prevented even when working in a cold region.

  In the above-described embodiment, the urea water tank 34 is disposed on the right side frame 6E side (the left and right outer sides) by making the short plate 15 of the fuel tank 12 adjacent to the outside. However, the present invention is not limited to this. For example, a short tank of the fuel tank is disposed on the bottom plate 6A and the vertical plates 6B and 6C (inside left and right) forming the center frame, and the urea water tank is disposed. It is good also as a structure which arrange | positions inside the left and right direction, or arrange | positions the short board of a fuel tank in the front side or the back side, and arrange | positions the urea water tank in the front side or the back side.

  Further, in the embodiment, the case where the fuel tank 12 is arranged so as to be arranged on the right side of the hydraulic oil tank 11 has been described as an example. However, the present invention is not limited to this. For example, the fuel tank may be arranged on the front side of the hydraulic oil tank.

  In the embodiment, the case where only the oxidation catalyst 25 is provided in the cylindrical case 24 of the first exhaust gas aftertreatment device 23 has been described as an example. However, the present invention is not limited to this. For example, in the cylindrical case of the first exhaust gas aftertreatment device, a particulate matter removing filter (abbreviated as DPF for short) located on the downstream side of the oxidation catalyst. It is good also as a structure which provides.

  In the embodiment, the small turning excavator 1 in which the upper turning body 4 can turn substantially within the vehicle width of the lower traveling body 2 is illustrated. However, the present invention is not limited to this, and may be applied to a hydraulic excavator including an upper swing body that is elongated in the front and rear directions.

  Further, in the embodiment, the hydraulic excavator 1 including the crawler type lower traveling body 2 is described as an example of the construction machine. However, the present invention is not limited to this, and may be applied to, for example, a hydraulic excavator provided with a wheel-type lower traveling body. Besides, it can be widely applied to other construction machines such as hydraulic cranes.

1 Excavator (construction machine)
2 Lower traveling body 4 Upper revolving body 5 Working device 6 Revolving frame 6A Bottom plate (center frame)
6B Left vertical plate (center frame)
6C Right vertical plate (center frame)
6D Left side frame 6E Right side frame 8 Engine 10 Hydraulic pump 12 Fuel tank 13 Bottom plate 13A Left edge (one edge)
13B Right edge (other edge)
14 Long plate 15 Short plate 15B Upper edge 16 Front L-shaped side plate (L-shaped side plate)
16A Long side plate portion 16B Short side plate portion 16B1 Upper end edge 17 Rear L-shaped side plate (L-shaped side plate)
17A Long side plate portion 17B Short side plate portion 17B1 Top edge 18 Stepped upper plate 18A High surface portion 18B Low surface portion 18C Vertical surface portion 18D Oil supply port 20 Exhaust pipe 27 Urea water injection valve (NOx purification device)
28 Second exhaust gas aftertreatment device (NOx purification device)
34 Urea water tank 35 Vertical tank portion 35B Inner side surface 35C Outer side surface 36 Horizontal tank portion 36K Notch portion 39 Level gauge 41 Heater (urea water heating member)

Claims (5)

A self-propelled lower traveling body, an upper revolving body mounted on the lower traveling body so as to be able to swivel, and a work device provided on the front of the upper revolving body so as to be able to move up and down,
The upper revolving structure includes a revolving frame that forms a support structure with a center frame and a side frame, an engine mounted in a laterally extending state on the rear side of the revolving frame in the left and right directions, and left and right A hydraulic pump provided in the engine located on one side of the direction, a fuel tank provided in the swivel frame located in front of the engine and the hydraulic pump and storing fuel supplied to the engine; A NOx purification device having a urea selective reduction catalyst and a urea water injection valve provided in the exhaust pipe of the engine for removing nitrogen oxides contained in the exhaust gas, and supplying the NOx purification device to the urea water injection valve In a construction machine comprising a urea water tank for storing urea water,
The fuel tank is
A rectangular bottom plate;
A long plate having a long rising height from the inner edge of the left and right sides of the bottom plate,
A short plate that is opposed to the inner edge of the bottom plate and rises from the outer edge in the left and right directions and is shorter than the height of the long plate,
Between the long plate and the short plate, two side surfaces facing in the front and rear directions are formed, and an intermediate portion between the long plate and the short plate is cut into an L shape, and a long side plate portion A pair of L-shaped side plates before and after the short side plate portion is integrally formed;
The long plate, the short plate, and the pair of L-shaped side plates that cover the upper ends of the long plate and the high surface portion at the same height as the upper ends of the long side plate portions, the short plate, and the short side plate Constructed in a box shape with a stepped upper plate consisting of a low surface portion at the same height as the upper end of the portion, and a vertical surface portion connecting between the high surface portion and the low surface portion,
The urea water tank includes a vertical tank portion extending upward and downward along the vertical surface portion between a high surface portion and a low surface portion of the stepped upper plate, and an upper portion of the vertical tank portion. It is formed as an inverted L-shaped container by a horizontal tank part extending laterally inward in the left and right directions toward the high surface part ,
By arranging the fuel tank on the revolving frame so that the short plate faces the outside of the upper revolving body, the vertical tank portion of the urea water tank is arranged to face the outside of the upper revolving body. Construction machine characterized by being made . The fuel tank has a configuration in which the short plate is adjacent to the outside by disposing the left and right outer edges of the bottom plate on the side frame side of the revolving frame,
The construction machine according to claim 1, wherein the vertical tank portion of the urea water tank is configured to be adjacent to the outside by being disposed closer to the side frame than the vertical surface portion of the stepped upper plate. A vertical surface portion of the stepped upper plate forming the fuel tank is formed to be inclined from the high surface portion toward the low surface portion,
The vertical tank portion of the urea water tank is configured to be inclined by making an inner surface facing the vertical surface portion and an outer surface facing the inner surface parallel to the vertical surface portion. The construction machine described. The high surface portion of the stepped upper plate forming the fuel tank is provided with a fuel filler port for supplying fuel into the fuel tank,
The construction machine according to claim 1, 2, or 3, wherein the horizontal tank portion of the urea water tank is formed with a cutout portion for avoiding the fuel filler opening.   In the urea water tank, a liquid level gauge that extends upward and downward in the vertical tank section and measures the amount of the urea water in the urea water tank, and a lateral direction from the lower end of the liquid level gauge. The construction machine according to claim 1, 2, 3, or 4, wherein the construction machine includes a urea water heating member that extends and heats the urea water.

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