JP2011016506A - Construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a heat retaining property, water supply performance and maintainability in a tank for a liquid reducing agent without complicating a constitution.SOLUTION: This construction machine is provided with a heat exchanger unit 13 in front of an engine room 7, and mounted with the tank 11 for the liquid reducing agent storing the liquid reducing agent 11. The heat exchanger unit 7 is installed at support frames 15 and 15 having a space. The heat retaining property, the water supply performance and the maintainability of the tank 11 for the liquid reducing agent are improved by arranging the tank 11 for the liquid reducing agent in the space at the support frames 15 and 15.

Description

  The present invention relates to a construction machine, and more particularly, to a construction machine equipped with a liquid reducing agent tank storing a liquid reducing agent.

  In recent years, construction equipment such as hydraulic excavators equipped with diesel engines has been equipped with exhaust gas treatment equipment in the exhaust system of diesel engines to meet higher-level exhaust gas regulations. Is released into the atmosphere through the NOx reduction catalyst provided in

  Conventionally, as this kind of exhaust gas treatment apparatus, a urea selective reduction type NOx treatment apparatus using a urea aqueous solution (liquid reducing agent) is often adopted, and the urea aqueous solution is stored in a liquid reducing agent tank. The liquid reducing agent tank is connected to the exhaust pipe by a liquid reducing agent supply pipe, and the urea aqueous solution in the liquid reducing agent tank can be supplied to the downstream side of the exhaust pipe by the liquid reducing agent supply pump. (For example, refer to Patent Document 1).

JP 2003-20936 A

  The aqueous urea solution is easily frozen when the temperature is below the freezing point, and when it is frozen, the aqueous urea solution cannot be used as a liquid reducing agent. Therefore, various techniques for preventing freezing of the urea aqueous solution have been developed. For example, by installing a heater (heating means) in the liquid reducing agent tank and attaching a temperature sensor, and outputting a command signal from the computer to the heater (temperature control means) based on the detection signal from the temperature sensor, the liquid A technology for heating the inside of the reducing agent tank has been developed.

  However, when the heating means and the temperature control means are provided as described above, the structure becomes complicated and the equipment cost increases. In the cold season, it is necessary to constantly heat the liquid reducing agent tank in order to prevent the urea aqueous solution in the liquid reducing agent tank from freezing. As a result, the consumption of electric energy for heating increases. To do.

  Further, since the liquid reducing agent tank is installed in a narrow area of the upper swing body, when the aqueous solution of urea is supplied to the liquid reducing agent tank or when the maintenance work of the liquid reducing agent tank is performed. In addition, the worker is forced to take an unnatural working posture, and there is a problem that the water supply and maintenance of the liquid reducing agent tank are not good.

  Therefore, there is a technical problem to be solved in order to improve the heat retention, water supply and maintainability of the liquid reducing agent tank without complicating the configuration, and the present invention solves this problem. With the goal.

The present invention has been proposed to achieve the above object, and the invention according to claim 1 is a liquid reductant tank in which a heat exchanger unit is disposed in front of an engine and the liquid reductant is stored. The heat exchanger unit is attached to a support frame having a space, and the liquid reductant tank is kept warm by installing the liquid reductant tank in the space in the support frame. Provided is a construction machine characterized in that it can be configured.

  According to this configuration, the heat exchanger unit mounting support frame located in front of the engine is heated by heat radiation from the engine, so that the heat retention performance of the liquid reducing agent tank installed in the support frame is improved.

  In addition, when the liquid reducing agent is replenished to the reducing agent tank or when the liquid reducing agent tank is maintained, the liquid reducing agent can be easily replenished or maintained from the outside of the space of the support frame. Can be implemented.

  According to the first aspect of the present invention, since the liquid reducing agent tank installed in the support frame for mounting the heat exchanger unit is warmed by heat radiation from the engine, the heat retaining property is improved. Thus, it is possible to prevent the liquid reducing agent in the liquid reducing agent tank from freezing even when it is cold.

  In this case, since equipment such as a heater and temperature control means is not required separately, the configuration is simplified as compared with the conventional example, and the equipment cost is reduced. Furthermore, the present invention can eliminate waste of electrical energy.

  Further, when replenishing the liquid reducing agent tank or performing maintenance of the liquid reducing agent tank, the work can be easily and quickly performed from the outside of the space portion of the support frame. The water supply and maintenance of the liquid reducing agent tank can be improved.

The side view of the hydraulic excavator (construction machine) which shows one Example of this invention. The top view which shows the upper turning body of the hydraulic shovel which concerns on one Example. The perspective view explaining the installation location of the tank for liquid reducing agents which concerns on one Example.

  The present invention has a heat exchanger unit disposed in front of the engine in order to achieve the object of improving the heat retention, water supply and maintenance of the liquid reducing agent tank without complicating the structure, and In a construction machine equipped with a liquid reducing agent tank storing a liquid reducing agent, the heat exchanger unit is attached to a support frame having a space portion, and the liquid reducing agent tank is installed in the space portion in the support frame. This was realized by enhancing the heat retaining property of the liquid reducing agent tank.

  A preferred embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a hydraulic excavator as an example of a construction machine. As shown in the figure, an upper swing body 2 is mounted on the lower traveling body 1 so as to be capable of swinging, and a cab 3 is provided on one front side of the upper swing body 2. In addition, the boom 4 is pivotally attached to the front center portion of the upper swing body 2 so that the boom 4 can be raised and lowered, and an arm 5 is connected to the distal end portion of the boom 4 so as to be rotatable up and down. A bucket 6 is attached so as to be rotatable up and down.

As shown in FIG. 2, an engine room 7 is provided at the rear of the upper swing body 2, and a diesel engine 8 is installed in the engine room 7. An exhaust pipe 9 is connected to the diesel engine 8, and an exhaust gas treatment device 10 is installed on the downstream side of the exhaust pipe 9 in order to comply with higher-order exhaust gas regulations. As the exhaust gas treatment apparatus 10 according to the present embodiment, a urea selective reduction type NOx treatment apparatus using a urea aqueous solution (liquid reducing agent) is adopted.

  A cooling fan 12 is disposed in front of the diesel engine 8 (front side in FIG. 2), and a heat exchanger unit 13 is installed in front of the cooling fan 12.

  As shown in FIG. 3, a heat exchanger 14 such as a radiator and an oil cooler is built in the heat exchanger unit 13. The heat exchanger unit 13 is attached to support frames 15 and 15 having horizontal portions that are separated from each other in the vertical direction, and the support frames 15 and 15 are fixed on a revolving frame 16.

  A space is formed inside the support frames 15, 15, and a metal liquid reducing agent tank 11 is installed in the space. Further, a water supply port (not shown) is provided on the upper surface or upper side of the liquid reducing agent tank 11.

  Further, the aqueous urea solution used in the exhaust gas treatment device 10 is stored in the liquid reducing agent tank 11. The liquid reducing agent tank 11 is connected to the exhaust gas treatment device 10 via a liquid reducing agent supply pipe (not shown).

  As described above, according to the present invention, the heat exchanger unit 13 disposed in front of the diesel engine 8 is attached to the support frames 15, 15, and the liquid reducing agent tank 11 is installed in the space in the support frames 15, 15. Therefore, the heat retaining property of the liquid reducing agent tank 11 is improved.

  That is, during operation of the diesel engine 8, the temperature in the engine room 7 is always maintained at a predetermined temperature or higher due to the heat released from the diesel engine 8, so that the inside of the support frames 15 and 15 for mounting the heat exchanger unit. The space is also heated to a predetermined temperature. As a result, the liquid reducing agent tank 11 installed in the space in the support frames 15 and 15 is always kept warm above a predetermined temperature.

  Thus, for example, even in the cold season when the temperature is below freezing, the temperature of the liquid reducing agent tank 11 can be kept above a predetermined value, so that the urea aqueous solution in the liquid reducing agent tank 11 can be frozen in a low temperature environment. Can be prevented.

  In this case, the liquid reducing agent tank 11 is installed in the space in the support frames 15 and 15 for attaching the existing heat exchanger unit to improve the heat retention, so that a heating means such as a heater, a temperature control means, etc. No additional equipment is required. Accordingly, the structure is simplified as compared with the conventional example, and the equipment cost is hardly required. In addition, the waste of electric energy for heating the liquid reducing agent tank 11 is eliminated.

  Further, when the aqueous urea solution is replenished to the liquid reducing agent tank 11 or when the maintenance and inspection of the liquid reducing agent tank 11 is performed, an operator can easily perform from outside the space portion of the support frames 15 and 15. Can work on. Accordingly, the urea aqueous solution replenishment operation and the maintenance / inspection operation of the liquid reducing agent tank 11 can be executed quickly, and the water supply and maintenance performance of the liquid reducing agent tank 11 are improved.

  Furthermore, since the liquid reducing agent tank 11 is installed in the support frames 15 for mounting the heat exchanger unit, the degree of freedom in layout is improved.

  It should be noted that the present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.

  The present invention can be applied to any construction machine equipped with a liquid reducing agent tank in which a liquid reducing agent other than an aqueous urea solution is stored in the liquid reducing agent tank.

2 Upper swing body 7 Engine room 8 Diesel engine 9 Exhaust pipe 10 Exhaust gas treatment device 11 Liquid reductant tank 13 Heat exchanger unit 15 Support frame (for mounting heat exchanger unit)

Claims (1)

In a construction machine in which a heat exchanger unit is disposed in front of an engine and a liquid reducing agent tank storing a liquid reducing agent is mounted, the heat exchanger unit is attached to a support frame having a space, and the support frame A construction machine characterized in that the liquid reducing agent tank can be kept warm by installing the liquid reducing agent tank in an inner space.

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