JP4851370B2 - Construction machinery - Google Patents

Description

  The present invention relates to a construction machine such as a hydraulic excavator in which an engine serving as a power source is mounted on an upper swing body, for example.

  Generally, a hydraulic excavator used for excavation work such as earth and sand is a self-propelled lower traveling body, an upper revolving body that is turnably mounted on the lower traveling body via a revolving device, and the upper revolving body It is comprised by the working device provided in the front side so that a heel-and-back movement was possible. Further, the lower traveling body is provided with a crawler type or wheel type traveling portion on both the left and right sides thereof. On the other hand, the upper swing body is equipped with an engine for driving a hydraulic pump at the rear of the swing frame, and on the front side of the swing frame is a cab, a fuel tank, a hydraulic motor, a hydraulic oil tank, a control valve, a swing motor, Many devices such as a center joint are provided.

  A diesel engine is generally used as an engine for a hydraulic excavator. This diesel engine is said to emit a large amount of nitrogen oxide (hereinafter referred to as NOx), and a large truck or bus using this diesel engine is equipped with a NOx purification device for purifying NOx. There is something. As this NOx purification device, a device is known in which urea water is mixed with exhaust gas, and the exhaust gas is subjected to a reduction reaction with a catalyst to be decomposed into water and nitrogen (for example, Patent Document 1, Patent Document 2, Patent). Reference 3).

JP 2004-257325 A JP 2003-20936 A JP 2005-334681 A

  Patent Document 1 and Patent Document 2 include a urea aqueous solution tank that stores a urea aqueous solution, an injection nozzle that is connected to the urea aqueous solution tank and injects urea water into an exhaust pipe of an engine, and urea water (ammonia). It is mainly constituted by a urea selective reduction catalyst that reduces NOx in the mixed exhaust gas to water and nitrogen.

  By the way, the invention of Patent Document 2 describes a configuration in which a urea aqueous solution tank, an injection nozzle, and a urea selective reduction catalyst are provided on an upper swing body of a hydraulic excavator. However, the upper swing body of the excavator is equipped with many devices such as cab, engine, hydraulic pump, heat exchanger, fuel tank, hydraulic oil tank, control valve, swing motor, center joint, etc. The upper swing body is formed in a small size so that the swing operation can be performed even in a narrow work site.

  Therefore, it is difficult to provide a space for arranging the urea aqueous solution tank, the injection nozzle, and the urea selective reduction catalyst in the upper swing body. In particular, the urea aqueous solution tank generates ammonia when the internal urea aqueous solution rises to 40 ° C. or higher. Therefore, the urea aqueous solution tank is not suitable for being arranged adjacent to a device having a high temperature such as an engine or a control valve. As a result, the installation location of the urea aqueous solution tank is limited, so that it is not possible to select a position where water supply work and maintenance work can be easily performed, and there is a problem that workability deteriorates.

  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 urea aqueous solution tank in an appropriate place, and perform a urea aqueous solution water supply operation, a urea aqueous solution tank maintenance operation, and the like. It is an object of the present invention to provide a construction machine that can be easily performed.

A construction machine according to the present invention comprises a self-propelled lower traveling body and an upper revolving body that is mounted on the lower traveling body via a swivel device so as to be capable of swiveling and is provided with an engine serving as a power source. The traveling body includes a track frame in which the turning device is attached in the center, and a traveling unit provided on both the left and right sides of the track frame, and an exhaust pipe of the engine includes nitrogen oxides in the exhaust gas. And a urea aqueous solution tank for storing a urea aqueous solution to be injected into the exhaust pipe, located upstream of the urea selective reduction catalyst .

In order to solve the above-mentioned problem, the feature of the configuration adopted by the invention of claim 1 is that the track frame includes a center frame located in the center and left and right sides provided on the left and right sides of the center frame. , The right track side frame, and the center frame includes a central frame portion located at the center, left and right front legs extending from the central frame portion toward the track side frames, and the central frame. Left and right rear legs extending from each part toward the respective track side frames, and the urea aqueous solution tank is located between two adjacent leg parts among the four legs constituting the center frame. It is that it was set as the structure provided in.

  The invention according to claim 2 is that the urea aqueous solution tank is formed as a separate container from the track frame and is integrally attached to the track frame.

  According to a third aspect of the present invention, the track frame is formed as a can manufacturing structure comprising an upper plate, a lower plate, and a side plate connecting between the upper plate and the lower plate. A closed space is defined in a part of the track frame, and the closed frame is used to integrally form the track frame.

According to a fourth aspect of the present invention, the track frame includes an upper plate, a lower plate disposed at a lower side of the upper plate, and a plurality of standing uprights so as to connect the upper plate and the lower plate. And a support cylinder provided in the upper and lower directions at the center of the upper plate and the lower plate, and the urea aqueous solution tank is located between the upper plate and the lower plate. The configuration is such that the support cylinder is surrounded and disposed at an outer position thereof.

  According to the first aspect of the present invention, for example, a large number of devices are mounted, and the size has been reduced so that the work can be performed in a narrow work site. Further, a urea aqueous solution tank for storing the urea aqueous solution can be provided by using the track frame of the lower traveling body.

  Thus, the urea aqueous solution stored in the urea aqueous solution tank can be injected into the exhaust pipe of the engine, and the nitrogen oxide (NOx) in the exhaust gas is reduced by the urea selective reduction catalyst provided in the exhaust pipe. Can be decomposed into water and nitrogen.

As a result, in the case of a construction machine composed of a lower traveling body and an upper rotating body, the urea aqueous solution tank is provided on the track frame of the lower traveling body, so that it is not heated by the equipment that becomes hot, and the water supply work and the maintenance work You can freely choose a place where it is easy to do. Moreover, since the track frame is in a low position, when replenishing the urea aqueous solution, it is not necessary to go up to a high place and can be easily replenished from the ground.
Furthermore, since the urea aqueous solution tank is provided in the space between the two adjacent leg portions of the center frame, the urea aqueous solution tank can be arranged using a place where there are no other devices or structures around. Further, the appearance of the urea can be improved by placing the urea aqueous solution tank between the legs.

  According to the invention of claim 2, since the urea aqueous solution tank is formed as a container separate from the track frame, only a small container for storing the urea aqueous solution can be formed using a material having corrosion resistance to urea. Can be manufactured inexpensively. Further, when coating a material having corrosion resistance, only a small range of coating can be used. Further, since the urea aqueous solution tank is configured to be attached to the track frame, when a problem occurs in the urea aqueous solution tank, only this urea aqueous solution tank can be easily replaced.

  According to the invention of claim 3, by defining the sealed space in a part of the track frame made of the can manufacturing structure to which the upper plate, the lower plate, the side plate and the like are fixed, the urea space is utilized using this sealed space. The aqueous solution tank can be formed integrally with the track frame. Therefore, the urea aqueous solution tank can be easily provided with a small number of parts.

According to invention of Claim 4 , a urea aqueous solution tank can be provided using the space between the upper board and lower board which form a track frame. Further, by providing the urea aqueous solution tank at the outer position surrounding the support cylinder, it is possible to easily reach from the periphery of the lower traveling body, and the urea aqueous solution can be easily replenished.

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

  First, FIGS. 1 to 12 show a first embodiment of the present invention. In FIG. 1, 1 is a hydraulic excavator as a construction machine used for excavation work such as earth and sand. 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 roughly constituted by the working device 5 provided on the front side.

  Here, the configuration of the crawler type lower traveling body 2 will be described. The lower traveling body 2 is generally constituted by a track frame 6, a driving wheel 15, an idle wheel 16, a crawler belt 17 and the like which will be described later. Further, a urea aqueous solution tank 32 described later is attached to the lower traveling body 2.

  Reference numeral 6 denotes a track frame constituting a main body portion of the lower traveling body 2. As shown in FIGS. 2 to 8, the track frame 6 is provided on a center frame 7 to be described later, a round cylinder 12 provided in the center of the center frame 7, and both left and right sides of the center frame 7. The left and right track side frames 13 and 14 are generally configured.

  Reference numeral 7 denotes a center frame located at the center of the track frame 6. As shown in FIG. 3, the center frame 7 includes a central frame portion 7A located at the center, a left front leg portion 7B and a right front leg portion 7C that are located on the front side of the central frame portion 7A and extend leftward and rightward. And a left rear leg portion 7D and a right rear leg portion 7E, which are located on the rear side of the central frame portion 7A and extend obliquely. The front end sides of the left front leg portion 7B and the left rear leg portion 7D are attached to the left track side frame 13, and the front end sides of the right front leg portion 7C and the right rear leg portion 7E are attached to the right track side frame 14.

  Further, as shown in FIG. 4, the center frame 7 has the legs 7B to 7E inclined downward so that the lower (bottom) portion does not come into contact with an obstacle such as a rock while traveling on the work site. The frame portion 7A is arranged at a high position. The center frame 7 is formed as a box-shaped can-making structure by an upper plate 8, a lower plate 9, side plates 10, a support cylinder 11 and the like which will be described later.

  Reference numeral 8 denotes an upper plate that forms an upper portion of the center frame 7, and the upper plate 8 is formed in a substantially X shape using a steel plate or the like. That is, the upper plate 8 includes a center plate 8A which is flat at the center, a left front plate 8B which extends from the left front side of the center plate 8A to the left front side and becomes the upper surface of the left front leg 7B, and the center plate 8A. A right front plate 8C extending from the right front side to the right diagonal front side and serving as the upper surface of the right front leg portion 7C, and a left rear plate 8D extending from the left rear side of the central plate 8A to the left diagonal rear side and serving as the upper surface of the left rear leg portion 7D The right rear plate 8E, which extends from the right rear side of the central plate 8A to the right diagonal rear side and serves as the upper surface of the right rear leg 7E.

  Reference numeral 9 denotes a lower plate of the center frame 7 disposed facing the lower side of the upper plate 8. The lower plate 9 is formed using a steel plate or the like in substantially the same manner as the upper plate 8. That is, the lower plate 9 includes a center plate 9A, a left front plate 9B serving as a lower surface of the left front leg portion 7B, a right front plate 9C serving as a lower surface of the right front leg portion 7C, and a left rear plate serving as a lower surface of the left rear leg portion 7D. 9D and the right rear plate 9E which becomes the lower surface of the right rear leg 7E are formed in a substantially X shape.

  Here, the lower plate 9 forms an upper and lower space for attaching a urea aqueous solution tank 32 to be described later by providing a desired interval between the lower plate 9 and the upper plate 8. In addition, as shown in FIG. 7, the lower plate 9 is formed with four bolt insertion holes 9F and a drain plaque insertion hole 9G located on the front side of the central plate 9A to which the urea aqueous solution tank 32 is attached.

  Reference numeral 10 denotes a plurality of side plates provided by connecting the upper plate 8 and the lower plate 9, and each of the side plates 10 includes, for example, a left and right front side plate 10A, intermediate side plates 10B and 10C, and a rear side. It is comprised from faceplate 10D etc. Each side plate 10 forms a side portion of each leg portion 7B to 7E of the center frame 7. The side plates 10A, 10B, 10C, and 10D have upper and lower end portions fixed to the upper plate 8 and the lower plate 9 by welding means, and the end portion on the turning center side is a support cylinder described later. It is fixed to the body 11 using welding means, thereby forming a can-making structure having a box structure.

  Reference numeral 11 denotes a support cylinder provided in the upper and lower directions at a central position between the upper plate 8 and the lower plate 9. As shown in FIGS. 5 and 6, the support cylinder 11 is formed as a cylinder having substantially the same diameter as a circular cylinder 12 described later. The support cylinder 11 is formed to have a smaller diameter than the central plate 8A of the upper plate 8 and the central plate 9A of the lower plate 9. As a result, the front, rear, left, and right sides, which are the outer positions of the support cylinder 11, are positioned between the four legs 7 </ b> B to 7 </ b> E that constitute the center frame 7, and are horizontal for mounting the urea aqueous solution tank 32. A space in the direction is formed in a trapezoidal shape.

  Reference numeral 12 denotes a circular cylinder (center circle) provided on the center frame 7, and the circular cylinder 12 is for attaching the turning device 3. Further, the round cylinder 12 is disposed coaxially with the support cylinder 11 at the center position of the center frame portion 7A, and is integrally fixed to the upper surface of the center frame portion 7A using welding means or the like.

  Reference numeral 13 denotes a left track side frame fixed to the left side of the center frame 7, and reference numeral 14 denotes a right track side frame fixed to the right side of the center frame 7. The track side frames 13 and 14 are formed to extend in the front and rear directions.

  Reference numeral 15 denotes a driving wheel provided at one end of the front and rear sides of the track side frames 13 and 14, 16 denotes an idler wheel provided at the other front and rear ends of the track side frames 13 and 14, and 17 denotes driving. The crawler belts wound around the wheel 15 and the idler wheel 16 (both shown only on the right side in FIG. 1) are shown. The drive wheel 15, idle wheel 16 and crawler belt 17 constitute a left and right traveling unit that causes the lower traveling body 2 to travel.

  Next, the configuration of the upper swing body 4 will be described. The upper swing body 4 includes a swing frame 18 to which the swing device 3 is attached, a cab 19 provided on the left front side of the swing frame 18 on which an operator rides, and a power source mounted on the rear side of the swing frame 18. An engine 20 formed, a hydraulic pump 21 driven by the engine 20, a hydraulic oil tank 22, a fuel tank 23, a control valve 24 provided on the front side of the engine 20, and a turning center of the turning frame 18. In addition to a center joint 25 (shown in FIG. 9), a counterweight 26 attached to the rear end of the revolving frame 18, a building cover 27 covering the engine 20 and the like, a urea selective reduction catalyst 29 described later. The urea aqueous solution injection device 30 and the piping 31 are generally configured.

  Here, the engine 20 is configured as a diesel engine. As shown in FIG. 9, the engine 20 includes an engine main body 20A and an exhaust pipe 20B that discharges exhaust gas from the engine main body 20A. Moreover, although the diesel engine 20 is highly efficient and excellent in durability, harmful substances such as nitrogen oxides (NOx) are discharged as exhaust gas.

  Therefore, the hydraulic excavator 1 according to the first embodiment includes a NOx purification device that mixes urea water with exhaust gas, causes the exhaust gas to undergo a reduction reaction with a urea selective reduction catalyst (urea SCR), and decomposes it into water and nitrogen. I have. This NOx purification device is composed of a catalyst case 28, a urea selective reduction catalyst 29, a urea aqueous solution injection device 30, and a urea aqueous solution tank 32 provided on the lower traveling body 2, which will be described later. It has been known.

  Reference numeral 28 denotes a catalyst case provided in the engine 20 of the upper swing body 4. The catalyst case 28 is provided in the middle of the exhaust pipe 20 </ b> B of the engine 20. The catalyst case 28 contains a urea selective reduction catalyst 29 described later, an oxidation catalyst (not shown) for reducing ammonia, and the like.

  Reference numeral 29 denotes a urea selective reduction catalyst of a NOx purification device provided in the engine 20 of the upper swing body 4. The urea selective reduction catalyst 29 is located in the downstream side of the urea aqueous solution injection device 30 described later and is accommodated in the catalyst case 28. The urea selective reduction catalyst 29 is a catalyst that causes nitrogen oxide (NOx) in the exhaust gas to undergo a reduction reaction with ammonia generated from the urea water and decomposes it into water and nitrogen.

  A urea aqueous solution injection device 30 is located upstream of the urea selective reduction catalyst 29 and attached to the exhaust pipe 20 </ b> B of the engine 20. This urea aqueous solution injection device 30 injects the urea aqueous solution stored in the urea aqueous solution tank 32 toward the exhaust gas flowing through the exhaust pipe 20B. The urea aqueous solution injection device 30 adjusts the injection amount of the urea aqueous solution in accordance with conditions such as the flow rate, temperature, and components of the exhaust gas, and is connected to a controller (not shown).

  31 is a pipe provided by connecting the urea aqueous solution injection device 30 and a urea aqueous solution tank 32 described later. The pipe 31 has, for example, two pipe lines composed of an outflow pipe and an inflow pipe, and one end thereof is connected to the outlet 34 and the inlet 35 of the urea aqueous solution tank 32 on the lower traveling body 2 side. On the other hand, the other side extends through the upper swing body 4 via the center joint 25 and is connected to the urea aqueous solution injection device 30.

  A urea aqueous solution tank 32 is attached to the track frame 6 of the lower traveling body 2. The urea aqueous solution tank 32 stores a urea aqueous solution that generates ammonia when heated. As a specific example, the urea aqueous solution tank 32 is designed to store, for example, about 10 liters of an aqueous solution of 32.5% urea. These values vary depending on the engine 20 displacement, characteristics, and the like. The urea aqueous solution tank 32 is formed as a sealed container for storing the urea aqueous solution, and is formed of a metal material having excellent corrosion resistance, such as SUS304 or SUS316.

  Here, the urea aqueous solution tank 32 may be formed in a box shape using a general steel material and coated with a resin material having corrosion resistance, such as polyethylene, polypropylene, or fluororesin, on the inner surface or the like. Alternatively, the resin-made urea aqueous solution tank 32 may be formed using a resin material such as polyethylene, polypropylene, or a fluororesin.

  The urea aqueous solution tank 32 is disposed on the front side, which is the outer position of the support cylinder 11 of the track frame 6, and between the four left leg portions 7B to 7E, the adjacent left front leg portion 7B and right front leg portion 7C. In other words, they are arranged so as to fit in a trapezoidal space on the lower plate 9 sandwiched between the left and right front side plates 10A.

  As shown in FIGS. 10 to 12, the external shape of the urea aqueous solution tank 32 is as follows: a wide rectangular front surface 32A, a narrow rectangular rear surface 32B, and left and right side surfaces 32C extending obliquely. 32D and the trapezoidal upper surface 32E and lower surface 32F are formed as an irregular shaped rectangular container. Further, as shown in FIG. 12, four screw seats 32 </ b> G are provided on the lower surface 32 </ b> F of the urea aqueous solution tank 32 so as to correspond to the bolt insertion holes 9 </ b> G of the lower plate 9 of the track frame 6.

  Further, the configuration of the urea aqueous solution tank 32 will be described in detail. 33 is a water supply port provided on the upper surface 32E of the urea aqueous solution tank 32 (see FIG. 10), and the water supply port 33 is a spout for replenishing the urea aqueous solution. Is configured. Reference numeral 34 denotes an outlet 34 and 35 provided on the rear surface 32B of the urea aqueous solution tank 32, and reference numeral 35 denotes an inlet 35 provided on the rear surface 32B (see FIG. 11). The outflow port 34 and the inflow port 35 are connected to the pipe 31 so that an aqueous urea solution is supplied from the outflow port 34, and the aqueous urea solution is returned to the inflow port 35. Reference numeral 36 denotes a drain plug 36 provided on the lower surface 32F.

  On the other hand, 37 is a temperature sensor provided on the upper surface 32E of the urea aqueous solution tank 32, and the temperature sensor 37 measures the temperature of the urea aqueous solution in the urea aqueous solution tank 32. Reference numeral 38 denotes a level sensor provided on the rear surface 32B of the urea aqueous solution tank 32. The level sensor 38 measures the remaining amount (liquid level) of the urea aqueous solution. Similarly, 39 is a urea identification sensor (quality sensor) provided on the rear surface 32B. The urea identification sensor 39 determines whether or not a correct urea aqueous solution is supplied. Furthermore, 40 is also a heater provided on the rear surface 32B, and the heater 40 warms the urea aqueous solution so as not to freeze. Reference numeral 41 denotes a breathing plug (breather) provided on the upper surface 32E.

  The urea aqueous solution tank 32 is placed on the front side of the center plate 9A of the lower plate 9 constituting the track frame 6. In this state, a bolt (not shown) is inserted into the bolt insertion hole 9F and screwed into the screw seat 32G. By wearing, it can be detachably attached to the front position of the track frame 6. When the urea aqueous solution tank 32 is attached to the track frame 6, the outlet 34 and the inlet 35 are connected to the urea aqueous solution injection device 30 using the pipe 31 or the like. Further, the temperature sensor 37, the level sensor 38, the urea identification sensor 39, and the heater 40 are connected to a controller that controls them.

  Thus, the urea aqueous solution tank 32 can be attached to the lower traveling body 2 using the track frame 6. Thereby, the urea aqueous solution tank 32 can supply the stored urea aqueous solution to the urea aqueous solution injection device 30 through the pipe 31. In addition, when replenishing the urea aqueous solution, by going to the vicinity of the urea aqueous solution tank 32 and opening the water supply port 33, without getting on a high place with a water supply tank (not shown), The urea aqueous solution can be easily replenished from the ground.

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

  First, the operator gets on the cab 19 of the upper swing body 4, starts the engine 20, and drives the hydraulic pump 21. Thereby, the pressure oil from the hydraulic pump 21 is supplied to various actuators via the control valve 24. When an operator who has boarded the cab 19 operates an operation lever (not shown) for traveling, the crawler belt 17 can be driven around by the drive wheels 15, and the hydraulic excavator 1 is moved forward or backward by the lower traveling body 2. Can be made. On the other hand, by operating an operation lever (not shown) for work, the work device 5 can be moved up and down to perform soil excavation work or the like.

  Further, during operation of the engine 20, nitrogen oxides (NOx), which are harmful substances, are discharged from the exhaust pipe 20B. At this time, the urea aqueous solution in the urea aqueous solution tank 32 is supplied to the urea aqueous solution injection device 30 via the pipe 31 and is injected into the exhaust gas from the injection device 30 to generate ammonia. Thereby, in the urea selective reduction catalyst 29, the amount of nitrogen oxides discharged can be reduced by reducing the nitrogen oxides to water and nitrogen and exhausting them outside through the oxidation catalyst.

  As described above, the upper swing body 4 of the hydraulic excavator 1 includes the cab 19, the engine 20, the hydraulic pump 21, the hydraulic oil tank 22, the fuel tank 23, the control valve 24, the center joint 25, and the piping, wiring connected thereto, In addition to being equipped with auxiliary equipment, it is compact in size so that it can work in a narrow work site.

  However, according to the first embodiment, the urea aqueous solution tank 32 for storing the urea aqueous solution can be provided by using the track frame 6 of the lower traveling body 2. Thus, the urea aqueous solution stored in the urea aqueous solution tank 32 can be injected into the exhaust pipe 20B of the engine 20 from the urea aqueous solution injection device 30, and the exhaust gas is exhausted by the urea selective reduction catalyst 29 provided in the exhaust pipe 20B. Nitrogen oxide (NOx) in the gas can be decomposed into water and nitrogen by a reduction reaction.

  As a result, even in the hydraulic excavator 1 in which it is difficult to mount the urea aqueous solution tank 32 on the upper swing body 4, a device for purifying nitrogen oxides composed of the urea selective reduction catalyst 29, the urea aqueous solution tank 32, and the like is provided. Can do. Thereby, the discharge | emission amount of a nitrogen oxide can be reduced.

  Further, the urea aqueous solution tank 32 is provided between the two left front leg portions 7B and the right front leg portion 7C adjacent to the center frame 7 in the track frame 6 of the lower traveling body 2, so It can be arranged at a lower position compared to the case of mounting. Therefore, when the urea aqueous solution tank 32 is replenished with the urea aqueous solution, it can be easily replenished from the ground without getting on the crawler belt 17 or the building cover 27, and workability can be improved.

  Moreover, the urea aqueous solution tank 32 has two legs surrounded by the upper plate 8, the lower plate 9, and the left and right front side plates 10A on the front side of the support cylinder 11 with respect to the center frame 7 constituting the track frame 6. It arrange | positions in the space between the parts 7B and 7C. Thereby, the operator can approach the urea aqueous solution tank 32 through the left and right crawler belts 17, and can perform the replenishment work more easily. Further, the urea aqueous solution tank 32 can be provided by using a place where there is no other equipment or structure around and is a dead space. Further, the appearance can be improved.

  On the other hand, the urea aqueous solution tank 32 is formed as a separate container from the track frame 6. As a result, when the urea aqueous solution tank 32 is manufactured, only a small container needs to be formed using a material having corrosion resistance to urea, and can be manufactured at low cost. In addition, when a material having corrosion resistance is coated, only a small range can be used. Furthermore, since the urea aqueous solution tank 32 is configured to be attached to the track frame 6, when a problem occurs in the urea aqueous solution tank 32, only this urea aqueous solution tank 32 can be easily replaced.

  Next, FIGS. 13 to 15 show a second embodiment of the present invention. The feature of the present embodiment is that the track frame is formed as a can manufacturing structure composed of an upper plate, a lower plate, and a side plate connecting between the upper plate and the lower plate, and the urea aqueous solution tank is formed from the can manufacturing structure. The present invention has a configuration in which a sealed space is defined in a part of the track frame, and is formed integrally with the track frame using the sealed space. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In FIG. 13, reference numeral 51 denotes a track frame according to the second embodiment, and 52 denotes a center frame located at the center of the track frame 51. The center frame 52 includes a central frame portion 52A, a left front leg portion 52B, a right front leg portion 52C, a left rear leg portion 52D, and a right rear leg portion 52E in substantially the same manner as the center frame 7 according to the first embodiment described above. It is configured. Further, the center frame 52 is formed as a box-shaped can manufacturing structure by an upper plate 53, a lower plate 54, side plates 55, a support cylinder 56 and the like which will be described later. However, the center frame 52 according to the second embodiment is different from the center frame 7 according to the first embodiment in that a urea aqueous solution tank 57 described later is integrally formed.

  53 is an upper plate forming an upper portion of the center frame 52, and the upper plate 53 is made of a steel plate or the like, and is substantially X by a center plate 53A, a left front plate 53B, a right front plate 53C, a left rear plate 53D, and a right rear plate 53E. It is formed in a letter shape.

  Reference numeral 54 denotes a lower plate of the center frame 52 disposed facing the lower side of the upper plate 53. The lower plate 54 is formed in a substantially X shape by a central plate 54A, a left front plate 54B, a right front plate 54C, a left rear plate 54D, and a right rear plate 54E using a steel plate or the like in substantially the same manner as the upper plate 53. .

  Here, the upper plate 53 and the lower plate 54 form an upper surface and a lower surface of a urea aqueous solution tank 57 described later. Therefore, the upper plate 53 and the lower plate 54 form a space in the upper and lower directions for securing the internal volume of the urea aqueous solution tank 57 by providing a desired interval.

  Reference numeral 55 denotes a plurality of side plates provided between the upper plate 53 and the lower plate 54. As shown in FIG. 14, each of the side plates 55 includes, for example, left and right front side plates 55A, intermediate side plates 55B, 55C, rear side plate 55D, and the like. Further, each side plate 55A, 55B, 55C, 55D has its upper and lower ends fixed to the upper plate 53 and the lower plate 54 by welding means, and the end on the turning center side is described later. The cylindrical body 56 is fixed by welding means, whereby the center frame 52 is formed as a can-making structure having a box structure. Of the side plates 55A, 55B, 55C and 55D, the intermediate side plate 55B and the intermediate side plate 55C located on the right side form the front and rear surfaces of the urea aqueous solution tank 57.

  Reference numeral 56 denotes a support cylinder provided at a central position between the upper plate 53 and the lower plate 54. The support cylinder 56 is formed as a cylindrical body that is coaxially disposed with substantially the same diameter as the round cylinder 12. The support cylinder 56 forms the left side surface of the urea aqueous solution tank 57 as shown in FIG.

  Reference numeral 57 denotes a urea aqueous solution tank integrally formed with the track frame 51 according to the second embodiment. The urea aqueous solution tank 57 is disposed at the right outer position of the support cylinder 56 between the two right front leg portions 52C and the right rear leg portion 52E adjacent to the center frame 52. Further, the urea aqueous solution tank 57 is integrally formed with the track frame 52 by using a sealed space by defining a sealed space in a part of the center frame 52 formed of a can-making structure.

  That is, as shown in FIGS. 14 and 15, the urea aqueous solution tank 57 includes an upper plate 53 that forms an upper surface, a lower plate 54 that forms a lower surface, an intermediate side plate 55B that forms a front surface, and an intermediate side plate 55C that forms a rear surface. The support cylinder 56 forming the left side and the right side plate 58 closing the right outside form a sealed space for storing the urea aqueous solution. The urea aqueous solution tank 57 is provided with a water supply port 59, an outlet 60, an inlet 61, a drain plug 62, a temperature sensor 63, a level sensor 64, a respiratory plug 65, and the like.

  Furthermore, since the urea aqueous solution tank 57 is formed of a general steel material, the inner surface or the like is coated with a resin material having corrosion resistance, such as polyethylene, polypropylene, or fluororesin. In this case, since the urea aqueous solution tank 57 is small, the range for applying the resin coating can be reduced.

  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, the urea aqueous solution tank 57 defines a sealed space in a part of the center frame 52 made of a can-making structure, and the urea aqueous solution tank 57 is placed in the center frame using this sealed space. 52 can be integrally formed. Therefore, the urea aqueous solution tank 57 can be easily provided on the center frame 52 with a small number of parts only by newly providing one right side plate 58.

  In the first embodiment, the urea aqueous solution tank 32 has been described as an example in which the urea aqueous solution tank 32 is attached to the front portion of the center frame 7 on the front side of the support cylinder 11. However, the present invention is not limited to this, and the urea aqueous solution tank 32 may be attached to other positions such as the rear side, the left side, and the right side as long as it is an outer position surrounding the support cylinder 11, for example.

  In the first embodiment, only one urea aqueous solution tank 32 is attached between the adjacent left front leg 7B and right front leg 7C of the center frame 7 on the front side of the support cylinder 11. The case has been described as an example. However, the present invention is not limited to this. For example, as in the first modification shown in FIG. 16, the left rear leg 7D is provided between the two left front legs 7B and the right front leg 7C constituting the center frame 7. The urea aqueous solution tanks 32 and 32 'may be provided between the right rear leg portion 7E and the right rear leg portion 7E. Further, three or more urea aqueous solution tanks may be provided.

  On the other hand, in the second embodiment, the case where the urea aqueous solution tank 57 is formed integrally with the right outer side of the center frame 52 on the right side of the support cylinder 56 has been described as an example. However, the present invention is not limited to this, and the urea aqueous solution tank 57 may be integrally formed at other positions such as the front side, the rear side, and the left side as long as it is an outer position surrounding the support cylinder 11, for example.

  In the second embodiment, only one urea aqueous solution tank 57 is formed between the adjacent right front leg portion 52C and right rear leg portion 52E of the center frame 52 on the right side of the support cylinder 56. The case described above is described as an example. However, the present invention is not limited to this. For example, as in the second modification shown in FIG. 17, the urea aqueous solution tank 57 between the right front leg portion 52C and the right rear leg portion 52E on the right side of the support cylinder 56 is provided. In addition, the urea aqueous solution tank 71 may be provided between the left rear leg portion 52D and the right rear leg portion 52E on the rear side of the support cylindrical body 56. In this case, the urea aqueous solution tank 71 may be integrally formed by attaching a rear side plate 72 that closes the rear outer side to the rear side of the support cylinder 56. Further, three or more urea aqueous solution tanks may be provided.

  Moreover, in 1st Embodiment, it demonstrated as what provided the circular cylinder 12 on both sides of the upper board 8 on the upper side of the support cylinder 11. As shown in FIG. However, the present invention is not limited to this. For example, the support cylinder and the round cylinder may be formed by one cylinder and provided so as to penetrate the upper plate. This configuration can be similarly applied to the second embodiment.

  Furthermore, in each embodiment, the hydraulic excavator 1 provided with the crawler type lower traveling body 2 having the driving wheels 15, the idle wheels 16, and the crawler belts 17 as traveling portions has been described as an example of the construction machine. However, the present invention is not limited to this. For example, the present invention may be applied to a hydraulic excavator provided with a wheel-type lower traveling body having a traveling portion such as a tire. Besides, it can be widely applied to other construction machines such as hydraulic cranes.

1 is a front view showing a hydraulic excavator according to a first embodiment of the present invention. It is a front view which expands and shows the track frame and urea aqueous solution tank in FIG. It is a top view which expands and shows a track frame and a urea aqueous solution tank. It is a right view which expands and shows a track frame and a urea aqueous solution tank. It is sectional drawing which looked at the track frame from the arrow VV direction in FIG. It is sectional drawing which looked at the track frame and the urea aqueous solution tank from the arrow VI-VI direction in FIG. It is a bottom view which expands and shows a track frame. It is a perspective view which expands and shows a track frame and a urea aqueous solution tank. It is a block diagram which shows the whole structure of the apparatus for purifying nitrogen oxide with an engine. It is an expansion perspective view which shows the urea aqueous solution tank from the diagonal front side by itself. FIG. 4 is an enlarged perspective view showing a urea aqueous solution tank alone from an oblique rear side. It is an enlarged bottom view showing a urea aqueous solution tank alone. It is a perspective view which shows the track frame and urea aqueous solution tank by the 2nd Embodiment of this invention. FIG. 14 is a partially broken plan view showing the track frame and urea aqueous solution tank of FIG. 13. It is sectional drawing of the principal part expansion which looked at the track frame and the urea aqueous solution tank from the arrow XV-XV direction in FIG. It is a top view which shows two urea aqueous solution tanks with a track frame by the 1st modification of this invention. It is a top view which shows the track frame by the 2nd modification of this invention, and two urea aqueous solution tanks.

Explanation of symbols

1 Excavator (construction machine)
2 Lower traveling body 3 Turning device 4 Upper turning body 6,51 Track frame 7,52 Center frame 7A, 52A Center frame portion 7B, 52B Left front leg portion 7C, 52C Right front leg portion 7D, 52D Left rear leg portion 7E, 52E Right Rear legs 8, 53 Upper plate 9, 54 Lower plate 10, 55 Side plate 11, 56 Support cylinder 12 Round barrel 13, 14 Track side frame 15 Driving wheel (traveling portion)
16 idler wheel (traveling part)
17 crawler belt (running part)
18 slewing frame 19 cab 20 engine 20A engine body 20B exhaust pipe 29 urea selective reduction catalyst 30 urea aqueous solution injection device 32, 57, 71 urea aqueous solution tank

Claims (4)

A self-propelled lower traveling body, and an upper revolving body that is mounted on the lower traveling body through a turning device so as to be capable of turning, and is provided with an engine that serves as a power source. It is composed of a track frame to which a turning device is attached, and traveling parts provided on both the left and right sides of the track frame ,
The exhaust pipe of the engine is provided with a urea selective reduction catalyst for selectively reducing nitrogen oxides in the exhaust gas,
In the construction machine has a structure that having a urea aqueous solution tank for storing the urea aqueous solution for injecting the exhaust pipe located upstream of the pre-Symbol urea selective reduction catalyst,
The track frame is composed of a center frame located in the center, and left and right track side frames provided on both the left and right sides of the center frame,
The center frame includes a central frame portion located at the center, left and right front legs extending from the central frame portion toward the track side frames, and from the central frame portion toward the track side frames. With extended left and right rear legs,
The construction machine characterized in that the urea aqueous solution tank is provided between two adjacent leg portions of the four leg portions constituting the center frame .   The construction machine according to claim 1, wherein the urea aqueous solution tank is formed as a separate container from the track frame and is integrally attached to the track frame. The track frame is formed as a can-making structure composed of an upper plate, a lower plate, and a side plate connecting between the upper plate and the lower plate,
The construction according to claim 1, wherein the urea aqueous solution tank defines a sealed space in a part of the track frame made of a can-making structure, and is configured to be integrally formed with the track frame using the sealed space. machine. The track frame includes an upper plate, a lower plate disposed at a lower side of the upper plate, a plurality of side plates erected so as to connect the upper plate and the lower plate, and the upper plate It is composed of a support cylinder provided in the upper and lower direction at the center position of the plate and the lower plate,
The aqueous urea solution tank, the construction machine according to claim 1, 2 or 3 comprising a structure arranged in its outer position surrounding the support tube body positioned between the upper and lower plates .

Images