JP2015101881A - Construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily install a duct which connects a urea water tank, a urea water pump, and an NOx cleaning device together, and to keep urea water at a proper temperature.SOLUTION: A fuel tank 12 is arranged, side by side in a right/left direction, outside a hydraulic oil tank 11 arranged in front of an oil pressure pump 10, and a urea water tank 13 which reserves urea water is provided above the fuel tank 12. The fuel tank 12 is provided with a urea water pump 17 which projects to above the oil pressure pump 10 and supplies the urea water in the urea water tank 13 to a urea water injection valve 25, and a post-treatment unit 19 is provided above an engine 8 adjacently to the urea water pump 17, and also provided with a urea selective reducing catalyst 28 which removes nitrogen oxide in an exhaust gas and the urea water injection valve 25. Then the urea water tank 13, urea water pump 17, and urea water injection valve 25 are connected together using a urea water duct 30.

Description

  The present invention relates to a construction machine such as a hydraulic excavator provided with a NOx purification device that purifies nitrogen oxides in exhaust gas, for example.

  Generally, a hydraulic excavator as a construction machine is a self-propelled lower traveling body, an upper revolving body mounted on the lower traveling body so as to be able to swivel around the center of a swiveling device, and an upper revolving body. It is comprised by the working apparatus provided so that movement was possible.

  The upper swing body includes a swing frame that forms a support structure, a counterweight that is provided on the rear side of the swing frame and that balances the weight of the working device, and that is located on the front side of the counterweight and is located behind the swing frame. Engine mounted horizontally in the left and right direction, a hydraulic pump provided in the engine, and provided on the turning frame at the turning center side on the front side of the hydraulic pump. The hydraulic oil tank, and a fuel tank provided in the revolving frame so as to be arranged on the outer side in the left and right directions with respect to the hydraulic oil tank.

  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 is, for example, a urea selective reduction catalyst that is provided in an exhaust pipe of an engine and removes nitrogen oxides in exhaust gas, and urea injection that injects a urea aqueous solution as a reducing agent upstream of the urea selective reduction catalyst. And a valve.

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

  Here, the urea water tank is disposed at a position away from the engine that is a heat source because the urea water tank may deteriorate when the temperature of the internal urea water rises. As the location of the urea water tank in this case, the inside of the equipment storage chamber (storage box) provided in the front side of the hydraulic oil tank and the fuel tank, that is, the right front portion of the swivel frame is known (for example, Patent Documents). 1).

JP 2013-2082 A

  In patent document 1 mentioned above, it is set as the structure which accommodates a urea water tank using the space in the apparatus accommodation chamber provided in the right front part of the turning frame. On the other hand, in recent hydraulic excavators, there is a hydraulic excavator called a small swivel type suitable for work in a narrow work site. In this small swivel excavator, the upper revolving body is almost within the width of the lower traveling body. The upper swing body is reduced in size so that it can be swung.

  Therefore, in the small swing type hydraulic excavator, the installation space on the swing frame is reduced, and therefore, the device storage chamber is used as a space for storing other devices such as a control valve device and a hydraulic hose. As a result, it is difficult to accommodate the urea water tank in the equipment housing chamber, and even if the urea water tank is housed in the equipment housing chamber, the urea water tank becomes small, so that sufficient urea water cannot be secured. There is a problem.

  In addition, when the urea water tank is disposed at the right front portion of the turning frame on the front side of the hydraulic oil tank and the fuel tank, the NOx purification device provided in the engine and the urea water tank are largely separated from each other. The pipe line to be made becomes long. As a result, labor is required for the operation of the pipe line, and the temperature of the urea water may rise while the urea water flows through the long pipe line.

  In particular, the temperature of the fuel tank rises due to the fuel heated by the engine, the temperature of the hydraulic oil tank rises due to the hydraulic oil heated by the action of decompression, etc. The temperature is rising by the hydraulic pump. Therefore, the connecting pipe line passes through the vicinity of the fuel tank and the hydraulic oil tank whose temperature has been increased, and is passed through the pump chamber and the engine chamber whose ambient temperature has been increased. As a result, even if the urea water tank is arranged away from the engine or the like, the temperature of the urea water rises while flowing through the pipeline, so that the urea water may be deteriorated. In addition, when the temperature of the urea water reaches 70 ° C. or higher, the life of the urea injection valve is extremely shortened, and in some cases, it may be damaged.

  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 install a pipeline for connecting a urea water tank, a urea water pump, and a NOx purification device with a simple operation. It is another object of the present invention to provide a construction machine capable of maintaining the temperature of urea water at an appropriate temperature and improving reliability.

  A construction machine according to the present invention is a self-propelled lower traveling body, an upper revolving body that is mounted on the lower traveling body so as to be able to swivel about the center of a swiveling device, and can be moved up and down on the upper revolving body. The upper revolving structure includes a revolving frame that forms a support structure, a counterweight that is provided on the rear side of the revolving frame and balances the weight of the working apparatus, and the counterweight An engine mounted on the front side in a horizontally placed state extending left and right behind the swivel frame, a hydraulic pump provided in the engine, and a swivel center side on the front side of the hydraulic pump And a fuel tank provided in the swivel frame so as to be arranged on the outside in the left and right directions with respect to the hydraulic oil tank.

  In order to solve the above-described problem, the configuration of the invention of claim 1 is characterized in that a urea water tank for storing urea water as a reducing agent is provided above the fuel tank, and the fuel tank is provided with the urea water tank. Is provided with a urea water pump for supplying the urea water stored in the urea water tank to the engine side so as to project over the hydraulic pump, and adjacent to the urea water pump on the upper side of the engine The position is provided with a NOx purification device comprising a urea selective reduction catalyst and a urea water injection valve for removing nitrogen oxides in exhaust gas discharged from the engine, and the urea water tank, the urea water pump, and the The NOx purification device is configured to be connected using a conduit through which urea water flows.

  According to the invention of claim 2, a partition plate having a heat insulating function is provided between the hydraulic pump and the urea water pump, and the partition plate prevents heat of the hydraulic pump from being transmitted to the urea water pump. It is in the configuration to do.

  According to a third aspect of the present invention, the upper rotating body includes a urea water tank cover that covers the urea water tank, a urea water pump cover that covers the urea water pump, and the NOx separately from an engine cover that covers the engine. The purifying device cover for covering the purifying device is provided.

  According to a fourth aspect of the invention, the urea water pump is arranged between the urea water tank and the urea water injection valve of the NOx purification device.

  According to the first aspect of the present invention, the fuel tank is arranged on the front side of the hydraulic pump so as to be aligned on the left and right sides with respect to the hydraulic oil tank, and the reducing agent is disposed above the fuel tank. A urea water tank for storing the urea water is provided. Therefore, even when the upper turning body is small and a space for installing the urea water tank cannot be secured, such as a small turning type construction machine, a sufficient capacity can be obtained by utilizing the space above the existing fuel tank. A urea water tank can be installed.

  On the other hand, the fuel tank is provided with a urea water pump for supplying the urea water stored in the urea water tank to the engine side so as to overhang the hydraulic pump, and adjacent to the urea water pump on the upper side of the engine. A NOx purifying device including a urea selective reduction catalyst and a urea water injection valve for removing nitrogen oxides in the exhaust gas discharged from the engine is provided at the position where the exhaust gas is discharged. On this basis, the urea water tank, the urea water pump, and the NOx purification device can be connected using a conduit through which the urea water flows.

  Therefore, since the urea water tank and the urea water pump can be arranged together in the vicinity of the NOx purification device, the pipe line used to connect them can be shortened. Thereby, since the urea water can be quickly supplied at a short distance from the urea water tank arranged close to the urea water injection valve of the NOx purification device, the temperature rise of the urea water being supplied can be suppressed.

  As a result, normal urea water can be supplied to the NOx purification device, and the reliability of the nitrogen oxide removal performance can be improved. Moreover, since the short pipe line can be easily routed, assembly work and maintenance work can be easily performed.

  According to the invention of claim 2, since the partition plate having a heat insulation function is provided between the hydraulic pump and the urea water pump, the partition plate prevents heat of the hydraulic pump from being transmitted to the urea water pump. can do. As a result, since the temperature rise of the urea water pump can be suppressed, the temperature rise of the urea water passing through the urea water pump can also be suppressed, and the life of the urea water can be extended.

  According to the invention of claim 3, the urea water tank cover can cover the urea water tank, the urea water pump cover can cover the urea water pump, and the purification device cover can cover the NOx purification device. In this manner, the urea water tank, the urea water pump, and the NOx purification device can be covered separately from the engine cover that covers the engine.

  According to the invention of claim 4, since the urea water pump is disposed between the urea water tank and the urea water injection valve of the NOx purification device, the urea water pump, the urea water tank, and the urea water injection valve are provided. They can be arranged in a substantially straight line. Therefore, the pipe line connecting the urea water pump, the urea water tank, and the urea water injection valve can be shortened. As a result, the urea water can be prevented from being deteriorated, and the assembly work and the maintenance work can be easily performed.

1 is a front view showing a hydraulic excavator according to a first 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 in FIG. 3 alone. 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, a urea water pump, and a part of urea water pipe line. It is an expanded sectional view showing the inside of an exhaust gas aftertreatment device. It is the perspective view which looked at the upper turning body provided with the partition plate by the 2nd Embodiment of this invention from the same position as FIG. It is an expansion perspective view which shows the partition plate in FIG. 8 alone. It is a front view which shows the hydraulic excavator which concerns on the 3rd Embodiment of this 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 the perspective view which looked at the upper turning body provided with the fuel tank and urea water tank by the 4th Embodiment of this invention from the same position as FIG. It is sectional drawing which expands and shows the fuel tank, urea water tank, etc. in FIG.

  Hereinafter, as a typical 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 the accompanying drawings.

  First, FIG. 1 to FIG. 7 show a first embodiment of the present invention. 1 and 2, 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.

  Here, 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. And a turning motor 3B that drives the upper turning body 4 to turn with a center O (shown in FIG. 3) as a turning center. A center joint 3 </ b> C for allowing pressure oil to flow between the lower traveling body 2 and the upper rotating body 4 is disposed at the center O of the swiveling 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 plurality of extended beams 6F that extend left and right from the bottom plate 6A and the respective vertical plates 6B and 6C and support the left and right side frames 6D and 6E at the front end portions thereof. .

  On the other hand, on the rear side of the turning frame 6, a plurality of, for example, four engine brackets 6G are provided 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 disposed at a position close to the turning center O 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.

  An engine 8 is provided on the rear side of the swivel frame 6 and is located on the front side of the counterweight 7, and 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. The mounting member 20A of the mounting base 20 constituting the mounting base for 10A and the post-processing unit 19 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 18 to be 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.

  Reference numeral 10 denotes a hydraulic pump attached to the 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 attaching the attachment member 20 </ b> A of the attachment base 20 to the engine 8.

  Reference numeral 11 denotes a hydraulic oil tank provided on the revolving frame 6 that is located on the revolving center O 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 elongated in the upward and downward directions.

  Next, the configuration of the fuel tank 12, the urea water tank 13 and the like which constitute a part of the features of the present invention will be described.

  Reference numeral 12 denotes a fuel tank provided in the revolving frame 6 so as to be arranged on the right side in the left and right directions 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. As shown in FIG. 6, the fuel tank 12 is formed as a box-shaped container by a front plate 12A, a rear plate 12B, a left side plate 12C, a right side plate 12D, an upper plate 12E, and a lower plate 12F.

  The fuel tank 12 has an upper portion formed in a step shape in order to mount a urea water tank 13 described later. That is, the upper surface plate 12E of the fuel tank 12 includes a high surface portion 12E1 located on the left side in the left and right directions and a falling portion located in the middle portion between the left and right directions and falling from the right edge of the high surface portion 12E1. 12E2 and a low surface portion 12E3 extending rightward from the lower end edge of the falling portion 12E2.

  An oil supply port 12G for supplying fuel is provided at the front side position of the high surface portion 12E1 so as to protrude upward. On the other hand, two screw seats 12H are provided in a position closer to the lower side of the falling portion 12E2 so as to be separated from each other in the front and rear directions, and fixing to be described later for fixing the urea water tank 13 to each screw seat 12H. A bolt 16 for attaching the tool 15 is screwed. Further, a pump bracket 12J is provided at an upper position of the rear plate 12B of the fuel tank 12. A urea water pump 17 described later is attached to the pump bracket 12J.

  A urea water tank 13 is provided on the upper surface plate 12E of the fuel tank 12. The urea water tank 13 stores urea water as a reducing agent supplied into the exhaust gas flowing through the connection pipe 24 on the upstream side of the urea selective reduction catalyst 28 of the aftertreatment unit 19 described later. The urea water tank 13 is arranged using the space above the fuel tank 12 and is formed in a shape that allows the urea water to be sucked out efficiently even when working in an inclined state.

  Specifically, the urea water tank 13 is formed as a box extending in the forward, backward, upward, and downward directions, that is, a flat box in the left and right directions so as to face the falling portion 12E2 of the upper surface plate 12E. The tank main body 13A and the bent tank portion 13B which is bent from the upper portion of the tank main body 13A to the left side and is disposed on the high surface portion 12E1 of the upper surface plate 12E are formed in an inverted L shape as a whole.

  Here, a stepped portion 13C for hooking a fixture 15 described later is provided at a position closer to the lower side of the tank body 13A. On the other hand, the left front side of the bent tank portion 13B is a cutout portion 13D for avoiding the fuel filler opening 12G. Further, on the upper side of the urea water tank 13, a water supply port 13 </ b> E for replenishing urea water is provided on the inclined surface on the front side. Further, on the upper side of the urea water tank 13, a lid body (not shown) connected to various sensors such as a fuel gauge and a thermometer, in addition to the urea water conduit 30 described later, is attached. 13F is provided.

  In this way, the urea water tank 13 formed in an inverted L shape can obtain a desired height dimension (depth dimension) by the tank body 13A, so that the liquid level can be maintained at a high position. . Therefore, for example, even when the urea water tank 13 is inclined during work on an inclined land, the suction port of the urea water conduit 30 can be arranged in the urea water.

  Reference numeral 14 denotes a heat insulating member provided in the urea water tank 13. The heat insulating member 14 prevents heat generated by the fuel tank 12 from being transmitted to the urea water tank 13, and is formed, for example, by molding a foamable resin material into a plate shape. Therefore, the heat insulating member 14 is provided across the position where the urea water tank 13 faces the fuel tank 12, that is, the left side surface of the tank body 13A and the lower surface of the bent tank portion 13B. Thereby, the heat insulation member 14 can prevent the heat from the fuel tank 12 from being transmitted to the urea water tank 13, and can suppress the temperature rise of the urea water in the urea water tank 13.

  As described above, the urea water tank 13 provided with the heat insulating member 14 is disposed along the upper surface plate 12 </ b> E of the fuel tank 12. In this state, a fixing tool 15 in which the plate body is bent in a C shape so as to be hooked on the stepped part 13C is arranged, and bolts 16 inserted into both ends of the fixing tool 15 are screwed to the screw seat 12H of the fuel tank 12. By doing so, the urea water tank 13 can be mounted on the fuel tank 12.

  Reference numeral 17 denotes a urea water pump provided in the fuel tank 12 so as to overhang the hydraulic pump 10. The urea water pump 17 supplies the urea water stored in the urea water tank 13 to the aftertreatment unit 19 provided in the engine 8. The urea water pump 17 is attached to the pump bracket 12J of the fuel tank 12, and an upstream supply pipe 30A of a urea water pipe 30 to be described later is connected to the suction port, and a discharge port (none of which is shown). Is connected to the downstream supply line 30B.

  Here, as shown in FIG. 3, the urea water pump 17 is connected between a urea water tank 13 and a later-described urea water injection valve 25 constituting the NOx purification device in detail with a later-described urea water conduit 30. The urea water tank 13 is disposed between the lid body 13F and the urea water injection valve 25. By arrange | positioning in this way, the urea water pump 17, the urea water tank 13, and the urea water injection valve 25 can be arrange | positioned substantially linearly. Thereby, the urea water pipe line 30 which connects the urea water pump 17, the urea water tank 13, and the urea water injection valve 25 can be shortened.

  Reference numeral 18 denotes an exhaust pipe (see FIG. 3) provided between the engine 8 and a first exhaust gas aftertreatment device 21 described later. The exhaust pipe 18 has one end on the inlet side connected to the exhaust port of the engine 8, and the other end on the outlet side connected to the air supply port 22 </ b> A of the cylindrical case 22 constituting the first exhaust gas aftertreatment device 21. It is connected.

  Next, in order to process the exhaust gas discharged from the engine 8, the configuration of the post-processing unit 19 provided connected to the exhaust side of the engine 8 will be described.

  Reference numeral 19 denotes a post-processing unit which is located on the right side of the engine 8 and provided on the upper side of the hydraulic pump 10. The aftertreatment unit 19 oxidizes and removes carbon monoxide (CO), hydrocarbons (HC), etc. contained in the exhaust gas discharged from the engine 8 and removes nitrogen oxides (NOx) contained in the exhaust gas. It purifies and further reduces the noise of the exhaust gas. The aftertreatment unit 19 includes a mounting base 20, a first exhaust gas aftertreatment device 21, a connecting pipe 24, a urea water injection valve 25, and a second exhaust gas aftertreatment device 26 which will be described later.

  As shown in FIGS. 5 and 7, the aftertreatment unit 19 has the first exhaust gas aftertreatment device 21, the connecting pipe 24, and the second exhaust gas aftertreatment device 26 assembled to the mounting base 20. The mounting base 20 is mounted on the engine 8 together with the hydraulic pump 10. Thus, the post-processing unit 19 is disposed at a position adjacent to the urea water pump 17 on the upper side of the engine 8. That is, the urea water tank 13, the urea water pump 17, and the post-processing unit 19 are arranged close to each other in the area on the right rear side of the upper swing body 4.

  Reference numeral 20 denotes a mounting base that forms a mounting base for the post-processing unit 19. The mounting base 20 is positioned on the upper side of the hydraulic pump 10 and is mounted on the pump mounting portion 8B of the engine 8. The mounting base 20 is for fixedly mounting the first exhaust gas aftertreatment device 21 and the second exhaust gas aftertreatment device 26 on the engine 8 side. The mounting base 20 includes a mounting member 20A facing the pump mounting portion 8B of the engine 8 across the mounting flange 10A of the hydraulic pump 10, and a base member 20B provided on the mounting member 20A. . The base member 20B is formed, for example, by bending a rectangular plate into an L shape.

  For example, when mounting the hydraulic pump 10 to the engine 8, the mounting base 20 applies the mounting member 20 </ b> A to the mounting flange 10 </ b> A of the hydraulic pump 10, and the bolts inserted into the mounting member 20 </ b> A in this state are pump mounting portions 8 </ b> B of the engine 8. Can be attached to the pump attachment portion 8B together with the attachment flange 10A (in a co-tightened state).

  Reference numeral 21 denotes a first exhaust gas aftertreatment device that constitutes a part of the aftertreatment unit 19. The first exhaust gas aftertreatment device 21 is provided on the outlet side of the exhaust pipe 18. The first exhaust gas aftertreatment device 21 includes a cylindrical case 22 extending in the front and rear directions of the upper swing body 4 and an oxidation catalyst 23 disposed in the cylindrical case 22. .

  The cylindrical case 22 is formed as a cylindrical sealed container, and an air supply port 22A formed of a tubular body is provided on the upstream side (front side portion) so as to protrude in the radial direction. The air supply port 22A is provided with a large number of through holes (not shown) located in the cylindrical case 22, and exhaust gas is reduced (silenced) by passing exhaust gas through the through holes. ) On the other hand, the outlet side of the exhaust pipe 18 is connected to the protruding end side of the air supply port 22A. Further, an exhaust port 22 </ b> B is provided on the downstream side (rear side portion) of the cylindrical case 22 so as to open in the radial direction.

  The oxidation catalyst 23 constitutes one of the processing members that purify the exhaust gas. The oxidation catalyst 23 is made of, for example, a ceramic cell-like cylinder, and has a large number of through holes formed in the axial direction thereof, and the inner surface is coated with a noble metal or the like. The oxidation catalyst 23 oxidizes and removes carbon monoxide (CO), hydrocarbons (HC), etc. contained in the exhaust gas by circulating the exhaust gas through each through hole at a predetermined temperature. It is.

  In the first exhaust gas aftertreatment device 21, the cylindrical case 22 is placed on the base member 20 </ b> B of the mounting base 20, and in this state, the base member 20 </ b> B is used by using a fastening band, a bolt, or the like (none is shown). It is fixed to.

  Reference numeral 24 denotes a connecting pipe connected to the exhaust port 22 </ b> B of the cylindrical case 22. The connecting pipe 24 is disposed on the outer periphery of the first exhaust gas aftertreatment device 21 so as to extend substantially in parallel with the first exhaust gas aftertreatment device 21. The connecting pipe 24 includes a cylindrical tube portion 24A, an upstream lid plate 24B that closes an inlet (rear) edge on the upstream side of the tube portion 24A, and an outlet on the downstream side of the tube portion 24A. The downstream lid plate 24 </ b> C closes the edge of the side (front side).

  The connection pipe 24 has an inlet side connected to an exhaust port 22B of the cylindrical case 22 and an outlet side connected to an air supply port 27A of a cylindrical case 27 constituting a second exhaust gas aftertreatment device 26 described later. Thereby, the connection pipe 24 can guide the exhaust gas discharged from the first exhaust gas aftertreatment device 21 to the second exhaust gas aftertreatment device 26.

  Reference numeral 25 denotes a urea water injection valve provided in the connecting pipe 24. The urea water injection valve 25 constitutes a part of the NOx purification device. The urea water injection valve 25 is attached to the upstream cover plate 24B of the connection pipe 24, connected to the urea water pump 17 via a downstream supply pipe 30B of the urea water pipe 30 described later, and via the return pipe 30C. The urea water tank 13 is connected. The urea water injection valve 25 injects the urea aqueous solution toward the exhaust gas flowing through the cylindrical portion 24 </ b> A of the connection pipe 24.

  Reference numeral 26 denotes a second exhaust gas aftertreatment device that constitutes a part of the aftertreatment unit 19. The second exhaust gas aftertreatment device 26 is provided on the outlet side of the connection pipe 24 and is disposed, for example, at a position overlapping the upper side of the first exhaust gas aftertreatment device 21. The second exhaust gas aftertreatment device 26 includes a cylindrical tubular case 27 and a urea selective reduction catalyst disposed in the cylindrical case 27 in substantially the same manner as the first exhaust gas aftertreatment device 21 described above. 28 and an oxidation catalyst 29 disposed on the downstream side of the urea selective reduction catalyst 28.

  Here, the second exhaust gas aftertreatment device 26 (cylindrical case 27, urea selective reduction catalyst 28, oxidation catalyst 29) and the urea water injection valve 25 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 27 is formed as a sealed container by closing both ends of the cylindrical body. An air supply port 27 </ b> A is provided in the front side portion, which is the upstream side of the cylindrical case 27, so as to be opened in the radial direction. On the other hand, an exhaust port 27B is provided at the rear side portion, which is the downstream side of the cylindrical case 27, and protrudes upward in the radial direction. The protruding end side of the exhaust port 27B is a tail tube 33D of the exterior cover 33 described later. It is connected to the. A large number of through holes are provided in the lower portion of the exhaust port 27B, and exhaust gas passes through each of the through holes, whereby exhaust sound is reduced (silenced).

  The urea selective reduction catalyst 28 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 28 normally causes nitrogen oxide (NOx) contained in the exhaust gas discharged from the engine 8 to selectively reduce and decompose into nitrogen and water by ammonia generated from the urea aqueous solution. Is.

  On the other hand, the oxidation catalyst 29 is formed of a ceramic cell-like cylindrical body in substantially the same manner as the oxidation catalyst 23 described above. A large number of through holes are formed in the axial direction, and the inner surface is coated with a noble metal. As a result, the oxidation catalyst 29 oxidizes residual ammonia remaining after the nitrogen oxides are reduced by the urea selective reduction catalyst 28 and separates it into nitrogen and water.

  In the second exhaust gas aftertreatment device 26, in the same manner as the first exhaust gas aftertreatment device 21, the cylindrical case 27 is fastened to the base member 20B of the mounting base 20 with a fastening band, a bolt or the like (all not shown). It is fixed using.

  Reference numeral 30 denotes a urea water pipe as a pipe provided by connecting the urea water tank 13, the urea water pump 17, and the urea water injection valve 25 constituting the NOx purification device. The urea water conduit 30 allows urea water to flow from the urea water tank 13 toward the urea water injection valve 25. Since the urea water pressurized by the urea water pump 17 circulates in the urea water conduit 30, for example, a flexible pressure-resistant hose is used.

  The urea water pipe line 30 includes an upstream supply pipe line 30 </ b> A connecting the urea water tank 13 (lid body 13 </ b> F) and the urea water pump 17, and a downstream supply pipe connecting the urea water pump 17 and the urea water injection valve 25. It is comprised by the path 30B and the return pipe line 30C which connects the urea water injection valve 25 and the urea water tank 13 (lid body 13F). As a result, the urea water conduit 30 circulates the urea water between the urea water tank 13 and the urea water injection valve 25.

  Here, the urea water tank 13, the urea water pump 17, and the urea water injection valve 25 constituting the NOx purification device are arranged together in the vicinity. In addition, the urea water pump 17, the urea water tank 13, and the urea water injection valve 25 are arranged in a substantially straight line. Therefore, the length of the urea water conduit 30 can be minimized. As a result, the urea water can be quickly supplied from the urea water tank 13 to the urea water injection valve 25 at a short distance, so that the temperature rise of the urea water during supply can be suppressed.

  Furthermore, 31 is a heat insulation pipe provided so as to cover a part of the urea water pipe line 30, for example, about half of the downstream supply pipe line 30B and the return pipe line 30C on the urea water injection valve 25 side. The heat insulating tube 31 is formed, for example, by molding a foamable resin material into a tubular shape. The heat insulating pipe body 31 insulates the urea water flowing through the urea water pipe line 30 so as not to increase in temperature due to heat generated by the engine 8, the hydraulic pump 10, the post-processing unit 19, and the like.

  Reference numeral 32 denotes a cab (see FIGS. 4 and 5) mounted on the left front side of the revolving frame 6. The cab 32 is carried by an operator, and includes a driver's seat on which the operator is seated, traveling Operating levers, working operating levers, etc. (both not shown) are provided.

  Reference numeral 33 denotes an exterior cover provided on the revolving frame 6 from the rear side to the side of the cab 32. The exterior cover 33 covers the engine 8, the heat exchange device 9, the hydraulic pump 10, the urea water tank 13, the urea water pump 17, the post-processing unit 19 and the like mounted on the revolving frame 6. Specifically, as shown in FIG. 2, the exterior cover 33 includes a right front cover 33 </ b> A provided at the right front portion so as to cover the front side from the upper side of the fuel tank 12, the engine 8, the heat exchange device 9, the hydraulic pump 10, and the like. The engine cover 33B is provided between the cab 32 and the counterweight 7 so as to cover it, and a left side cover 33C that falls from the left side of the engine cover 33B.

  The engine cover 33 </ b> B is provided with a tail pipe 33 </ b> D protruding above the post-processing unit 19. The tail tube 33D discharges exhaust gas to the outside, and is connected to an exhaust port 27B of a cylindrical case 27 constituting the second exhaust gas aftertreatment device 26.

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

  An operator who has boarded the cab 32 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, exhaust gas discharged from the engine 8 is discharged into the atmosphere through the exhaust pipe 18, the first exhaust gas aftertreatment device 21, the connection pipe 24, and the second exhaust gas aftertreatment device 26. The At this time, the oxidation catalyst 23 provided in the first exhaust gas aftertreatment device 21 oxidizes and removes carbon monoxide (CO), hydrocarbon (HC), etc. contained in the exhaust gas.

  On the other hand, the connecting pipe 24 injects urea water from the urea water injection valve 25 toward the exhaust gas, and the second exhaust gas aftertreatment device 26 decomposes nitrogen oxides into nitrogen and water by the urea selective reduction catalyst 28. To do. Further, the oxidation catalyst 29 oxidizes residual ammonia and separates it into nitrogen and water, so that the purified exhaust gas is discharged into the atmosphere.

  Here, when the urea water is supplied from the urea water tank 13 to the urea water injection valve 25, the temperature may increase due to heat generated by the engine 8, the hydraulic pump 10, the post-processing unit 19, and the like. This urea water is said to begin to deteriorate when it exceeds about 50 ° C.

  However, according to the first embodiment, the fuel tank 12 is arranged so as to be arranged on the right side which is the left side and the right side of the hydraulic oil tank 11 arranged on the front side of the hydraulic pump 10. A urea water tank 13 for storing urea water as a reducing agent is provided on the upper side of the fuel tank 12.

  On the other hand, the fuel tank 12 is provided with a urea water pump 17 for supplying the urea water stored in the urea water tank 13 to the urea water injection valve 25 on the engine 8 side so as to overhang the hydraulic pump 10. A post-processing unit 19 is provided at a position adjacent to the urea water pump 17 on the upper side of the engine 8, and the post-processing unit 19 is used to remove nitrogen oxides in the exhaust gas discharged from the engine 8. The urea selective reduction catalyst 28 and the urea water injection valve 25 are provided. On this basis, the urea water tank 13, the urea water pump 17, and the urea water injection valve 25 constituting the NOx purification device are connected using a urea water pipe 30 through which the urea water flows.

  Therefore, even when the upper revolving body 4 is small and a space for installing the urea water tank 13 cannot be secured as in the small swivel hydraulic excavator 1, the space above the existing fuel tank 12 is used. A urea water tank 13 having a capacity sufficient for long-time operation can be installed.

  Moreover, since the urea water tank 13 and the urea water pump 17 can be arranged together in the vicinity of the post-processing unit 19 (NOx purification device), the length of the urea water conduit 30 used to connect them is shortened. be able to. Thereby, urea water can be quickly supplied at a short distance from the urea water tank 13 disposed close to the urea water injection valve 25 of the NOx purification device.

  As a result, since the temperature rise of the urea water supplied toward the urea water injection valve 25 can be suppressed, normal urea water maintained at an appropriate temperature that does not deteriorate can be supplied to the NOx purification device. . As a result, the lifetime of the urea water can be extended, and the nitrogen oxide removal performance can be enhanced to improve the reliability. On the other hand, the short urea water pipe 30 is easy to handle and can be easily routed, so that assembly work and maintenance work can be easily performed.

  On the other hand, since the urea water pump 17 is arranged between the urea water tank 13 and the urea water injection valve 25, the urea water pump 17, the urea water tank 13 and the urea water injection valve 25 are arranged substantially in a straight line. can do. Therefore, the length dimension of the urea water pipe line 30 connecting the urea water pump 17, the urea water tank 13, and the urea water injection valve 25 can be substantially minimized. As a result, the urea water can be prevented from being deteriorated, and the assembly work and the maintenance work can be easily performed.

  Further, since a heat insulating member 14 having a heat insulating function is provided between the fuel tank 12 and the urea water tank 13, the heat from the fuel tank 12 is prevented from being transmitted to the urea water tank 13 by the heat insulating member 14. It is possible to suppress the temperature rise of the urea water in the urea water tank 13.

  Next, FIG. 8 and FIG. 9 show a second embodiment of the present invention. A feature of the present embodiment is that a partition plate having a heat insulating function is provided between the hydraulic pump and the urea water pump, and the partition plate prevents the heat of the hydraulic pump from being transmitted to the urea water pump. There is. 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. 8, reference numeral 41 denotes a partition plate provided between the hydraulic pump 10 and the urea water pump 17. The partition plate 41 is attached to the upper portion of the frame member 42 disposed on the revolving frame 6 so as to surround the engine 8 and the post-processing unit 19 for attaching the exterior cover 33 by means such as bolting or welding. It has been. The partition plate 41 is formed as a trapezoidal plate body having an inclined edge on the counterweight 7 side (rear side) in order to avoid the counterweight 7 on the rear side.

  As shown in FIG. 9, the partition plate 41 includes a plate portion 41A formed by bending the periphery of a trapezoidal steel plate downward, and a heat insulating portion 41B having a heat insulating function provided on the lower surface side of the plate portion 41A. It is comprised by. Further, the partition plate 41 is formed with a notch 41 </ b> C that is positioned closer to the rear side and allows the urea water conduit 30 to pass therethrough. Furthermore, the heat insulating portion 41B is formed by, for example, molding a foamable resin material into a plate shape.

  Thus, also in the second embodiment configured as described above, it is possible to obtain substantially the same operational effects as those of the first embodiment described above. In particular, in the second embodiment, since a partition plate 41 having a heat insulating function is provided between the hydraulic pump 10 and the urea water pump 17, the heat of the hydraulic pump 10 is urea water by the partition plate 41. Transmission to the pump 17 can be prevented. As a result, the temperature rise of the urea water pump 17 can be suppressed, the temperature rise of the urea water passing through the urea water pump 17 can be suppressed, and the life of the urea water can be extended.

  Next, FIG. 10 and FIG. 11 show a third embodiment of the present invention. The feature of the present embodiment is that the upper revolving structure includes a urea water tank cover that covers the urea water tank, a urea water pump cover that covers the urea water pump, and a purification that covers the NOx purification device separately from the engine cover that covers the engine. The apparatus cover is configured to be provided respectively. 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.

  10 and 11, reference numeral 51 denotes an exterior cover according to the third embodiment. The exterior cover 51 is provided on the revolving frame 6 from the rear side to the side of the cab 32 in substantially the same manner as the exterior cover 33 according to the first embodiment described above. However, the exterior cover 51 according to the third embodiment is provided with a urea water tank cover 51D, a urea water pump cover 51E, and a processing device cover 51F separately from the engine cover that covers the engine 8 and the like. This is different from the exterior cover 33 according to the first embodiment.

  That is, the exterior cover 51 is provided between the cab 32 and the counterweight 7 so as to cover the right front cover 51A 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. Engine cover 51B, left side cover 51C falling from the left side of engine cover 51B, urea water tank cover 51D, urea water pump cover 51E, and processing device as a purification device cover provided separately from these The cover 51F is included.

  The urea water tank cover 51 </ b> D covers the urea water tank 13 mounted on the upper side of the fuel tank 12. The urea water pump cover 51E is positioned behind the urea water tank cover 51D and covers the urea water pump 17. Further, the processing device cover 51F extends forward and rearward on the left side of the urea water tank cover 51D and the urea water pump cover 51E, and covers the second exhaust gas post-processing device 26 constituting the NOx purification device. The processing apparatus cover 51F is provided with a tail pipe 51G that protrudes upward from the rear side. The tail tube 51G is connected to the exhaust port 27B of the cylindrical case 27.

  Thus, also in the third embodiment configured as described above, it is possible to obtain substantially the same operational effects as those of the first embodiment described above. In particular, in the third embodiment, since the urea water tank cover 51D, the urea water pump cover 51E, and the processing device cover 51F are provided separately from the engine cover 51B that covers the engine 8, the urea water tank 13, the urea The water pump 17 and the second exhaust gas aftertreatment device 26 can be covered independently. As a result, individual maintenance operations can be easily performed, and even when damaged, they can be easily replaced.

  Next, FIG. 12 and FIG. 13 show a fourth embodiment of the present invention. The feature of this embodiment is that the upper surface plate of the fuel tank is formed flat and the urea water tank is mounted on the upper surface plate. 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.

  12 and 13, reference numeral 61 denotes a fuel tank according to the fourth embodiment. The fuel tank 61 includes a front plate 61A, a rear plate 61B, a left side plate 61C, a right side plate 61D, an upper surface plate 61E, and a lower surface plate 61F, and substantially the same as the fuel tank 12 according to the first embodiment. An oil supply port 61G is provided on the front side. However, the fuel tank 61 according to the fourth embodiment is different from the fuel tank 12 according to the first embodiment in that the upper surface plate 61E is formed flat.

  Reference numeral 62 denotes a mounting base provided as a part of the fuel tank 61 on the upper surface plate 61E of the fuel tank 61. For example, a urea water tank 63 and a urea water pump 17 which will be described later are attached to the mounting base 62. The mounting base 62 includes a plate portion 62A formed by bending the periphery of a rectangular steel plate downward, a heat insulating portion 62B having a heat insulating function provided on the lower surface side of the plate portion 62A, and a rear end portion of the plate portion 62A. And a rising plate 62C provided to rise. The plate 62A of the mounting base 62 is attached to the upper surface plate 61E of the fuel tank 61 using fastening means such as bolts or welding means. Moreover, the heat insulation part 62B is formed, for example, by molding a foamable resin material into a plate shape. Thereby, the heat insulation part 62B can prevent the heat from the fuel tank 61 from being transmitted to the urea water tank 63, and can suppress the temperature rise of the urea water in the urea water tank 63.

  The rising plate 62C is provided with a pump bracket 62D located on the rear surface side. The urea water pump 17 is attached to the pump bracket 62D. Furthermore, the rising plate 62C is provided with two fixing belts 64, which will be described later, between the front portion of the plate portion 62A and the upper portion of the rising plate 62C.

  63 shows a urea water tank according to the fourth embodiment provided on the plate portion 62A of the mounting base 62. The urea water tank 63 stores urea water as a reducing agent supplied to the post-processing unit 19. The urea water tank 63 is formed as a rectangular parallelepiped container by a front surface 63A, a rear surface 63B, a left surface 63C, a right surface 63D, an upper surface 63E, and a lower surface 63F. The urea water tank 63 is provided with a water supply port (not shown) for replenishing urea water, for example, located on the left surface 63C. On the other hand, the upper surface 63E of the urea water tank 13 is provided with a lid 63G to which the urea water conduit 30, lead wires and the like are attached. In addition to the left surface 63C, the water supply port may be provided on the front surface 63A, the right surface 63D, and the upper surface 63E.

  The urea water tank 63 configured in this manner is placed on the plate portion 62A of the mounting base 62 and is fixed between the front portion of the plate portion 62A and the upper portion of the rising plate 62C. A belt 64 is provided. The urea water tank 63 can be fixedly attached to the mounting base 62 by tightening the two fixing belts 64.

  Thus, also in the fourth embodiment configured as described above, it is possible to obtain substantially the same operational effects as those of the first embodiment described above. Particularly, in the fourth embodiment, the upper surface plate 61E of the fuel tank 61 is a flat surface, and the urea water tank 63 is provided on the flat upper surface plate 61E. Thereby, the urea water tank 63 can be easily provided also on the fuel tank 61 having a general shape. Further, since a heat insulating part 62B having a heat insulating function is provided between the fuel tank 61 and the urea water tank 63, heat from the fuel tank 61 is prevented from being transmitted to the urea water tank 63 by the heat insulating part 62B. In addition, the temperature rise of the urea water in the urea water tank 63 can be suppressed.

  In the first embodiment, the case where only the oxidation catalyst 23 is provided in the cylindrical case 22 of the first exhaust gas aftertreatment device 21 has been described as an example. However, the present invention is not limited to this. For example, the particulate matter removal filter (Diesel Particulate Filter, which is located downstream of the oxidation catalyst 23 in the cylindrical case 22 of the first exhaust gas aftertreatment device 21). It is good also as a structure which provides (it is also called DPF for short). This configuration can be similarly applied to other embodiments.

  In each embodiment, the small swing type hydraulic excavator 1 including the circular upper swing body 4 in which the counterweight 7 is disposed at a position close to the swing center O is illustrated. However, the present invention is not limited to this, and the present invention may be applied to a hydraulic excavator including an upper swing body that is elongated in the front and rear directions by largely separating the counterweight from the swing center.

  Furthermore, in each embodiment, the hydraulic excavator 1 provided with the crawler type lower traveling body 2 was 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)
DESCRIPTION OF SYMBOLS 2 Lower traveling body 3 Turning apparatus 4 Upper turning body 5 Working apparatus 6 Turning frame 7 Counterweight 8 Engine 10 Hydraulic pump 11 Hydraulic oil tank 12, 61 Fuel tank 12A, 61A Front plate 12B, 61B Rear plate 12C, 61C Left side plate 12D , 61D Right side plate 12E, 61E Top plate 12F, 61F Bottom plate 13, 63 Urea water tank 14 Thermal insulation member 17 Urea water pump 19 Post-processing unit 24 Connection pipe 25 Urea water injection valve (NOx purification device)
26 Second exhaust gas aftertreatment device (NOx purification device)
28 Urea selective reduction catalyst 30 Urea water pipe (pipe)
33, 51 Exterior cover 41 Partition plate 41B Heat insulation part 51B Engine cover 51D Urea water tank cover 51E Urea water pump cover 51F Treatment device cover (purification device cover)
62 Mounting base O Turning center

Claims (4)

A self-propelled lower traveling body, an upper revolving body mounted on the lower traveling body so as to be able to swivel about the center of the swiveling device, and a working device provided on the upper revolving body so as to be able to be lifted and lowered Become
The upper swing body includes a swing frame that forms a support structure, a counterweight that is provided on the rear side of the swing frame and that balances the weight of the working device, and is positioned on the front side of the counterweight, An engine mounted in a horizontal state extending in the left and right directions on the rear side, a hydraulic pump provided on the engine, and provided on the turning frame at the turning center side on the front side of the hydraulic pump A construction machine comprising: a hydraulic oil tank provided; and a fuel tank provided in the swivel frame so as to be arranged on the outside in the left and right directions with respect to the hydraulic oil tank,
On the upper side of the fuel tank, a urea water tank for storing urea water as a reducing agent is provided,
The fuel tank is provided with a urea water pump for supplying urea water stored in the urea water tank to the engine side so as to overhang the hydraulic pump,
A NOx purification device comprising a urea selective reduction catalyst and a urea water injection valve for removing nitrogen oxides in the exhaust gas discharged from the engine is provided at a position adjacent to the urea water pump on the upper side of the engine. ,
The construction machine characterized in that the urea water tank, the urea water pump, and the NOx purification device are connected using a conduit through which urea water flows.   The structure according to claim 1, wherein a partition plate having a heat insulating function is provided between the hydraulic pump and the urea water pump, and the partition plate prevents heat from the hydraulic pump from being transmitted to the urea water pump. The construction machine described.   Separately from the engine cover that covers the engine, the upper rotating body includes a urea water tank cover that covers the urea water tank, a urea water pump cover that covers the urea water pump, and a purification device cover that covers the NOx purification device. The construction machine according to claim 1 or 2, which is configured to be provided respectively.   The construction machine according to claim 1, 2 or 3, wherein the urea water pump is arranged between the urea water tank and a urea water injection valve of the NOx purification device.

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