JP2014114622A - Fuel tank of construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel tank of a construction machine capable of removing only moisture therefrom with a simple configuration.SOLUTION: A fuel tank 13 is installed on an upper rotating body 4 of a construction machine which has: a lower travelling body 2; the upper rotating body 4 rotatably mounted on the lower travelling body 2; and a work device 5 connected to the upper rotating body 4 so that one end thereof can be elevated. The fuel tank has: drain water discharge circuits 23A and 23B on a bottom section thereof to discharge drain water accumulated in the fuel tank; and an opening/closing cock 24 and a water-level gauge 28 arranged in the drain water discharge circuit. The water-level gauge allows visual measurement to be made from an outside.

Description

  The present invention relates to a fuel tank provided in a construction machine, and more particularly to a fuel tank suitable for draining water that has been mixed into the fuel tank.

  An example of a conventional fuel tank for an internal combustion engine is described in Patent Document 1. In the fuel tank described in this publication, when water contained in the fuel stored in the fuel tank is drained during engine operation, the fuel supply is prevented from being interrupted by the backflow of air from the drain port. Therefore, it is described that a water level meter that measures the water level in the fuel is provided in the fuel tank, and when the water level detected by this water level meter is higher than the predetermined water level, the electromagnetic valve provided at the bottom of the fuel tank is opened to drain the water. Has been.

  Patent Document 2 describes an example of a draining device for a fuel tank of a working vehicle that has a simplified structure, is easy to assemble, and can be expected to reduce costs. In the drainage device described in this publication, a drainage passage incorporating a float having a specific gravity intermediate between the specific gravity of light oil and water is formed at the bottom of the tank. When the drain cock provided on the downstream side of the float is opened, the water accumulated in the fuel tank continues to be drained from the drainage groove, and when there is no water in the fuel tank, the fuel in the fuel tank enters the float section. The float is configured to flow in and close the drain passage.

Japanese Utility Model Publication No. 07-20371 JP 2003-342972 A

  In the fuel tank draining device described in Patent Document 1, a water level meter is provided and the electromagnetic valve is controlled on the basis of the output of the water level meter. Have. However, since the fuel tank described in Patent Document 1 is premised on use in automobiles and the like, it is not sufficiently considered for use in work vehicles such as construction machines. That is, the construction environment or the like often has rough working environments, and a heavy load is applied even to the fuel tank due to impacts during the work. For this reason, it is necessary to take a load countermeasure for electronic parts such as a solenoid valve attached to the fuel tank, which may increase the cost. In addition, reliability that can withstand a large load is also required.

  Since the draining device for a fuel tank described in Patent Document 2 has a simple configuration, it can be realized at low cost. However, when this drainage device is used for construction machinery, the vehicle body is tilted or vibrated on rough terrain, so the fuel tank also tilts or vibrates, and the drainage passage attached to the fuel tank also tilts. Or vibrate. If the drainage device operates in this tilted state or vibrated state, the float does not always move as expected, and there is a risk that fuel will be mixed into the drainage and flow out of the drainage passage and be discarded to the outside.

  The present invention has been made in view of the above-mentioned problems of the prior art, and its purpose is to allow only water in the fuel tank to be drained by having a simple and reliable configuration of the fuel tank provided in the construction machine. There is to do.

  A feature of the present invention that achieves the above object includes a lower traveling body, an upper revolving body that is turnably mounted on the lower traveling body, and a work device that is connected to the upper revolving body so that one end side of the upper revolving body can be moved up and down. In a fuel tank mounted on the upper swing body of a construction machine, a drain water discharge circuit for discharging drain water stored in the fuel tank at the bottom of the fuel tank, and valve means interposed in the drain water discharge circuit And a water level meter, and the water level meter is provided so that the water level can be detected visually when the building cover of the construction machine is opened.

  In this feature, the water level meter is a float means, and the float means is a material having a specific gravity intermediate between water and light oil, and is preferably made of a hydrophobic material, and the valve means is an open / close cock. Yes, the float means may be made of polyethylene resin. Further, long elbow means communicating with the inside of the fuel tank is provided at the bottom of the fuel tank, and the upper end of the long elbow means is preferably equal to or less than the upper limit of the vertical movement range of the float means. The lower limit of the moving range is preferably equal to or less than the elbow means connected to the bottom of the fuel tank.

  According to the present invention, since the amount of drain water accumulated in the fuel tank of the construction machine can be visually checked, it is only necessary to drain the drain water when the amount of drain water is within a predetermined range, and the fuel is discharged together with the drain water. Can be prevented. In addition, it is possible to provide a drain water circuit with a simple structure and high reliability by simply projecting the elbow for fuel suction into the fuel tank.

1 is a side view of an embodiment of a construction machine according to the present invention. It is a top view of the construction machine shown in FIG. FIG. 3 is a front view of the fuel tank shown in FIG. 2. FIG. 3 is a partial view of a fuel tank provided in the construction machine shown in FIG. 2 and a perspective view. It is a fragmentary sectional view of the fuel tank shown in FIG.

  Hereinafter, an embodiment of a construction machine according to the present invention will be described with reference to the drawings. In the following description, a hydraulic excavator is exemplified as a construction machine. However, the construction machine is not limited to a hydraulic excavator, and the present invention is widely applied to other construction machines such as a hydraulic crane, a wheel loader, and a tractor. it can.

  FIG. 1 is a side view of a crawler hydraulic excavator 1 as a construction machine, and FIG. 2 is a top sectional view thereof. The excavator 1 is a self-propelled lower traveling body 2, an upper revolving body 4 that is turnably mounted on the lower traveling body 2 via a swivel device 3, and can be raised and lowered in front of the upper revolving body 4. And a working device 5 for performing excavation work of earth and sand. The turning device 3 turns the upper turning body 4 with respect to the lower traveling body 2 by rotationally driving a turning motor 3A (see FIG. 2).

  The working device 5 includes a boom 5A having one end thereof rotatably attached to a revolving frame 6 serving as a base of the upper revolving body 4, an arm 5B attached to the tip of the boom 5A so as to be able to move up and down, and an arm 5B. The bucket 5C is rotatably attached to the front end portion. The boom 5A is driven by a boom cylinder 5D, the arm 5B is driven by an arm cylinder 5E, and the bucket 5C is driven by a bucket cylinder 5F.

  A revolving frame 6 is disposed below the upper revolving structure 4, and the revolving frame 6 has a floor surface covered with a bottom plate made of a steel plate or the like as shown in FIG. On the bottom plate, left and right vertical plates extending in the front-rear direction, a plurality of side frames arranged at intervals on the left and right of the vertical plate, a plurality of projecting beams extending substantially perpendicular to the side frames, and the like are provided.

  A cab 7 on which an operator rides is mounted on the left front side of the revolving frame 6. Although not shown in the figure, a driver's seat on which an operator is seated, an operation lever for traveling, an operation lever for work, and the like are arranged inside the cab 7. A counterweight 8 is attached to the rear end of the revolving frame 6. The counterweight 8 balances the weight with the work device 5 and protrudes so that the rear surface side is curved.

  An engine 9 as a prime mover is mounted in a machine room 16 formed on the rear side of the revolving frame 6. The engine 9 is disposed on the front side of the counterweight 8 and is mounted on the turning frame 6 in a horizontally placed state extending in the left-right direction. A cooling fan 9 </ b> A for supplying cooling air to the heat exchanger 11 is provided on the output shaft of the engine 9 via a speed reduction unit. The heat exchanger 11 includes, for example, a radiator that cools the cooling water of the engine 9, an oil cooler that cools the hydraulic oil, an intercooler that cools the air sucked by the engine 9, and the like.

  A plurality of hydraulic pumps 15 are disposed on the right side of the engine 9. The hydraulic oil that circulates in the hydraulic pump 15 is stored in a hydraulic oil tank 12 that is located on the front side of the engine 9 and provided on the right side of the revolving frame 6. The hydraulic oil is used to drive the lower traveling body 2, the working device 5, and the like. A fuel tank 13 is disposed on the front side of the hydraulic oil tank 12.

  The engine 9, the heat exchanger 11, the hydraulic pump 15, etc. are covered with a building cover 14. The building cover 14 is located on the left side of the upper swing body 4 and covers the side of the heat exchanger 11, and the right side cover is positioned on the right side of the upper swing body 4 and covers the side of the hydraulic pump 15. And an upper surface cover that covers the upper side of the engine 9 and the like.

  Next, an embodiment of the fuel tank 13 according to the present invention disposed on the right side of the turning motor 3A will be described with reference to FIGS. FIG. 3 is a front view of the fuel tank 13. FIG. 4 is a partial perspective view of the fuel tank 13 as seen from below. FIG. 5 is a partial cross-sectional view of the fuel tank 13. 4 and 5 show only the lower part of the fuel tank 13.

  The fuel tank 13 has a rectangular parallelepiped tank body 13A for storing fuel (diesel fuel). An injection cylinder 39 is provided on the ceiling surface of the tank body 13A so as to protrude upward. The end of the injection cylinder 39 is a fuel filler port for fueling, and the lid 40 closes the fuel filler port. A key cylinder (not shown) that locks the lid 40 with respect to the injection tube 39 is attached to the lid 40.

  The fuel tank body 13A is made of sheet metal, and the front surface and the like are formed with irregularities for reinforcement. A return pipe 21 having a return port for returning the fuel discharged from the engine 9 to the fuel tank main body 13A is provided on one side surface of the tank main body 13A. The bottom surface 30 of the tank body 13A protrudes downward in a substantially truncated cone shape to form a convex bottom surface 30A, and a recess 30B (see FIG. 5) is formed at the center of the bottom in the fuel tank body 13A. doing. An elbow 32 is connected to the bottom surface 30A of the convex portion through a connection fitting 31, and is used for drain water to be described later in detail. A long elbow 22A, one end of which protrudes into the fuel tank body 13A, is also attached to the convex bottom surface 30A, and is used for fuel supply to the engine 9 described later in detail.

  One end of the hose 23 </ b> A is attached to the elbow 32, and the other end of the hose 23 </ b> A is attached to the base portion 25 </ b> A of the water level gauge 25. The upper part of the water level gauge 25 is fixed to the side surface 35 of the tank main body 13A with bolts 34. A cock 24 is also attached to the base 25A of the water level gauge 25 so that the drain water discharge circuit 23B can be opened and closed. On the other hand, a fuel suction circuit 22 is connected to the long elbow 22A via a connection fitting 33, so that fuel can be supplied to the engine. The drain discharge circuit 23B is a resin hose, and a resin hose is also used for the fuel suction circuit 22.

  The operation of the fuel tank 13 configured as described above will be described with reference to FIG. The water that has entered the tank main body 13A from the injection cylinder (fuel filler port) 39 or the like precipitates downward in the tank main body 13A due to the specific gravity difference between the diesel fuel that is the fuel and the water. In particular, since the recess 30B is formed at the center of the tank body 13A, drain water is collected around the recess 30B.

  Since the hydraulic excavator 1 is used not only on a flat ground but also on an inclined ground, the liquid level in the tank body 13A may tilt. Further, it may be undulated by vibrations generated by driving the excavator 1. However, the recess 30 </ b> B formed in the central portion of the tank body 13 </ b> A inhibits the mixing of the drain water 26 and the fuel 27.

  By the way, in the present invention, the tip of the long elbow 22A connected to the fuel suction circuit 22 is set to a position higher than the reference position by a predetermined amount H with respect to the position of the elbow 32. That is, if the fuel stored in the fuel tank is not higher than the height H, the fuel 27 is not supplied to the engine 9. In other words, if the drain water is not accumulated up to the height H, the drain water does not flow out to the engine 9 side. Therefore, it is only necessary to perform daily inspection with the position of the height H as the maximum allowable water level 29A of the drain water.

  On the other hand, when the drain water level is the minimum water level 29B at the position of the elbow 32, there is no drain water in the fuel tank main body 13A, and it is only included in the drain discharge circuit 23A. When the drain water height is equal to or lower than the minimum water level 29B, if the cock 24 is forcibly opened to drain the drain water, there is a high risk that not only the drain water but also the fuel will be discharged. Therefore, when the drain water level is below the minimum water level 29B, the drain is not discharged during daily inspection.

  The amount of fuel in the fuel tank body 13A can be constantly monitored from within the cab 7 by monitoring the output of the float 36 built in the fuel tank body 13A. However, since the amount of the drain water is not so large that the drain water amount must be constantly monitored, the drain water is visually monitored before the construction machine is started or after the work is completed. For convenience of this visual monitoring, a float type water level gauge 25 is interposed in the drain water discharge circuits 23A and 23B, and is fixed to the side surface 35 of the fuel tank body 13A. The float member 28 is made of a material having an intermediate specific gravity between diesel fuel, which is a fuel, and water, and is hydrophobic. For example, a float member made of polyethylene is used.

  In this embodiment, the water level gauge 25 is arranged on the side surface of the fuel tank main body 13A. However, if the visual observation surface is provided on the front side, the drain water amount can be easily monitored when the building cover is opened. Thereby, daily inspection work can be facilitated. As described above, since the minimum water level 29B and the allowable maximum water level 29A must be measured with a water level meter, the float member 28 can move up and down to the minimum water level 29B or less, and similarly can move up and down above the maximum water level 29A. .

  According to this embodiment, the amount of drain water in the fuel tank can be easily grasped only by visually observing the float type water level gauge, there is no fear of discharging the fuel together with the drain water, and the drain is provided on the fuel supply side. It is also possible to prevent water from entering.

  In the above embodiment, a float type water level gauge is used as the water level gauge. However, the liquid level is clearly indicated by applying a paint that changes color when wet with water on the back of the water level gauge or by a difference in refractive index. Even if is used, the same effect can be obtained.

DESCRIPTION OF SYMBOLS 1 ... Hydraulic excavator (construction machine), 2 ... Lower traveling body, 3 ... Turning device, 3A ... Turning motor, 4 ... Upper turning body, 5 ... Working device, 5A ... Boom, 5B ... Arm, 5C ... Bucket, 5D ... Boom cylinder, 5E ... arm cylinder, 5F ... bucket cylinder, 6 ... swivel frame, 7 ... cab, 8 ... counterweight, 9 ... engine, 11 ... heat exchange device, 12 ... hydraulic oil tank, 13 ... fuel tank, 13A ... (Fuel) Tank body, 14 ... Building cover, 15 ... Hydraulic pump, 16 ... Machine room, 22 ... Fuel suction circuit, 22A ... Long elbow, 23A ... Hose (drain water discharge circuit), 23B ... Drain water discharge circuit, 24 Open / close cock, 25 ... Water level gauge, 25A ... Base, 26 ... Moisture, 27 ... Fuel, 28 ... Float member (float means), 29A ... Maximum allowable water level, 29B ... Minimum 30 ... bottom surface, 30A ... convex bottom surface, 30B ... concave, 31 ... connection fitting, 32 ... elbow, 33 ... connection fitting, 34 ... mounting bolt, 35 ... side surface, 37 ... front surface, 39 ... injection cylinder, 40 ... lid.

Claims (5)

Mounted on the upper swing body of a construction machine comprising a lower traveling body, an upper swing body that is swingably mounted on the lower travel body, and a work device that is connected to the upper swing body so that one end side of the upper swing body is movable up and down. In the fuel tank,
A drain water discharge circuit for discharging drain water stored in the fuel tank and a valve means and a water level meter interposed in the drain water discharge circuit are provided at the bottom of the fuel tank. A fuel tank for a construction machine, characterized in that the water level can be detected visually when the building cover is opened.   2. The fuel for a construction machine according to claim 1, wherein the water level gauge is a float means, and the float means is a material having a specific gravity intermediate between water and light oil and is made of a hydrophobic material. tank.   3. The fuel tank for a construction machine according to claim 1, wherein the valve means is an open / close cock, and the float means is made of polyethylene resin.   The long elbow means communicating with the inside of the fuel tank is provided at the bottom of the fuel tank, and the upper end of the long elbow means is below the upper limit of the vertical movement range of the float means. The fuel tank for a construction machine according to any one of the above.   5. The fuel tank for a construction machine according to claim 4, wherein the lower limit of the vertical movement range of the float means is equal to or less than the elbow means connected to the bottom of the fuel tank.

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