fuel tank

Abstract

To provide a fuel tank that inhibits a deterioration in fuel by hindering contact between air and liquid fuel stored in a tank body.SOLUTION: A fuel tank having a tank body for storing liquid fuel includes a lid body in which a circular hole is formed and which is arranged in the state of floating on the fuel within the tank body, and a sphere that is fitted to the hole from below so as to close the hole.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a fuel tank having a tank body for storing liquid fuel. [Background technology]

[0002] A work machine such as a hydraulic excavator is equipped with an engine driven by liquid fuel and a fuel tank. The fuel is stored in the tank body of the fuel tank and supplied from the tank body to the engine. In recent years, biodiesel fuel has also been used as a renewable energy source. Biodiesel fuel tends to deteriorate more easily due to oxidation than light oil, which is a regular diesel fuel. As biodiesel fuel deteriorates, it may corrode the inside of the tank body or form small sludge clumps, which could cause engine piston rings to stick.

[0003] In contrast, the fuel degradation prediction device described in Patent Document 1 predicts the degree of oxidative degradation of fuel in order to determine the quality of stored fuel. The degradation prediction device includes a temperature sensor that detects the temperature of the fuel and a timer unit that measures the time required for the temperature sensor to detect the fuel temperature. The degree of oxidative degradation of the fuel is calculated based on the temperature detection result by the temperature sensor and the time measurement result by the timer unit, etc. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-148389 Summary of the Invention [Problem to be solved by the invention]

[0005] However, even if the degree of oxidation degradation of fuel can be predicted, when fuel is stored in the tank body for a long period of time, such as during marine transport of work machinery, there is a concern that the fuel may have deteriorated by the time the engine is started. Therefore, to ensure the smooth operation of work machinery, it is necessary to suppress fuel degradation inside the tank body.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and its object is to provide a fuel tank that prevents contact between the liquid fuel stored in the tank body and air, thereby suppressing fuel deterioration. [Means for solving the problem]

[0007] In order to achieve the above object, a representative aspect of the present invention is a fuel tank having a tank body for storing liquid fuel, wherein a circular hole is formed and the fuel is disposed in the tank body so as to float on the fuel. Plate and, While floating in the fuel, and a sphere that fits into the hole from below to close the hole. [Effects of the Invention]

[0008] According to the present invention, the liquid fuel stored in the tank body can be prevented from coming into contact with air, thereby suppressing deterioration of the fuel. Note that problems, configurations, and effects other than those described above will become clear from the description of the following embodiments. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a side view of a hydraulic excavator, which is a typical example of a work machine provided with a first embodiment of a fuel tank according to the present invention. [Figure 2] FIG. 2 is a plan view of the upper rotating body with the top cover removed. [Figure 3] FIG. 2 is a perspective view showing the fuel tank of the first embodiment. [Figure 4] FIG. 2 is a perspective view showing the flat plate and the sphere of the lid body. [Figure 5]FIG. 4 is a cross-sectional view showing the lid when fuel is stored in the tank body. [Figure 6] FIG. 4 is a cross-sectional view showing the lid when fuel is being supplied into the tank body. [Figure 7] FIG. 2 is a cross-sectional view of the fuel tank including a plan view of the lid as viewed from above. [Figure 8] 10 is a cross-sectional view showing the lid body and the tank body with the flat plate in contact with the stopper. FIG. [Figure 9] FIG. 6 is a cross-sectional view showing a fuel tank according to a second embodiment. [Figure 10] FIG. 10 is a cross-sectional view showing a lid provided on a fuel tank according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] (First embodiment) A first embodiment of a fuel tank according to the present invention will be described with reference to the drawings. The fuel tank of the first embodiment is provided in a work machine. FIG. 1 is a side view of a hydraulic excavator 1, which is a representative example of a work machine provided with the first embodiment of the fuel tank according to the present invention. Note that, unless otherwise specified, front, back, left, and right in this specification are based on the viewpoint of an operator who is on board and operating the hydraulic excavator 1.

[0011] The hydraulic excavator 1 comprises a lower traveling body 2, an upper rotating body 3 supported by the lower traveling body 2, and a work implement 4 attached to the upper rotating body 3. The lower traveling body 2 and the upper rotating body 3 are an example of the main body of the hydraulic excavator 1. The lower traveling body 2 comprises a pair of left and right endless tracks 8. When the rotation of a traveling motor (not shown) is transmitted to the pair of left and right endless tracks 8 and the endless tracks 8 rotate, the hydraulic excavator 1 travels. However, the lower traveling body 2 may be wheeled instead of being equipped with the endless tracks 8.

[0012] The upper rotating body 3 is supported on the lower traveling body 2 in a state in which it can be rotated by a rotating motor (not shown). The upper rotating body 3 mainly comprises a rotating frame 5 which serves as a base, a cab 7 located on the front left side of the rotating frame 5, a counterweight 6 located at the rear of the rotating frame 5, and an engine room (building) 10. The working device 4 is a front working machine that performs work such as excavating earth and sand, and is attached to the front center of the rotating frame 5 so as to be able to rotate up and down.

[0013] The working device 4 includes a boom 4a supported on the upper rotating body 3 so that it can be raised and lowered, an arm 4b supported swingably at the tip of the boom 4a, a bucket 4c supported swingably at the tip of the arm 4b, and hydraulic cylinders 4d to 4f that drive the boom 4a, arm 4b, and bucket 4c. The counterweight 6 is a heavy object used to balance the weight of the working device 4, and is supported by the rotating frame 5 at the rear end of the upper rotating body 3.

[0014] The cab 7 has an internal space in which an operator who operates the hydraulic excavator 1 sits. Inside the cab 7, there are arranged a seat (not shown) on which the operator sits, and operation devices (steering wheel, pedals, levers, switches, etc.) that the operator seated in the seat operates. When the operator sitting in the cab 7 operates the operation devices, the lower traveling body 2 travels, the upper rotating body 3 rotates, and the work device 4 operates.

[0015] The engine room 10 is provided between the cab 7 of the upper rotating body 3 and the counterweight 6, and is supported by the rotating frame 5 behind the working implement 4 and the cab 7 and in front of the counterweight 6. The engine room 10 extends across the entire left-right area of ​​the rotating frame 5. Figure 2 is a plan view of the upper rotating body 3 with the top cover removed.

[0016] A heat exchanger 11, an engine 12, and a muffler 13 are housed in this order from left to right inside the engine room 10. The heat exchanger 11 supplies coolant to the engine 12, cools the coolant returned from the engine 12 by heat exchange with air, and supplies the cooled coolant back to the engine 12. The engine 12 burns fuel and air supplied into its cylinder to generate rotational driving force. The muffler 13 discharges exhaust gas produced when the engine 12 burns fuel to the outside of the hydraulic excavator 1.

[0017] To prevent heat and vibrations generated when the engine 12 is running from escaping from the engine room 10, a partition wall 14 extending in the left-right direction is provided in front of the engine room 10. The partition wall 14 separates the space above the upper rotating body 3 in the front-rear direction. An oil tank 15, a control valve (C / V) 16, and a fuel tank 20 are arranged in front of the partition wall 14.

[0018] The oil tank 15 and fuel tank 20 are supported by the revolving frame 5 forward of the bulkhead 14 and at the right end of the upper revolving body 3. The oil tank 15 stores hydraulic oil to be supplied to the hydraulic actuators. The control valve 16 is supported by the revolving frame 5 forward of the bulkhead 14 and at the center of the upper revolving body 3 in the left-right direction. The control valve 16 controls the amount and direction of hydraulic oil supplied from the oil tank 15 to the hydraulic actuators.

[0019] The hydraulic oil stored in the oil tank 15 is pumped toward the hydraulic actuator by a hydraulic pump (not shown) that is rotated by the driving force of the engine 12. The control valve 16 is disposed in the hydraulic oil flow path from the hydraulic pump to the hydraulic actuator, and switches the amount and direction of hydraulic oil supply according to the amount of operation of the operating device.

[0020] The fuel tank 20 stores liquid fuel (for example, biodiesel fuel, diesel, or gasoline) to be supplied to the engine 12. The engine 12 is driven by the fuel supplied from the fuel tank 20. FIG. 3 is a perspective view showing the fuel tank 20 of the first embodiment. In FIG. 3, a portion of the fuel tank 20 is omitted to show the internal structure of the fuel tank 20.

[0021] The fuel tank 20 comprises a tank body 30 that stores liquid fuel 21, and a lid 40 housed inside the tank body 30. Air 22 is housed in the space above the fuel 21 inside the tank body 30. The fuel 21 is stored in a space below the lid 40 in the internal space of the tank body 30. The air 22 is housed in a space above the lid 40 in the internal space of the tank body 30.

[0022] The tank body 30 is a container that stores the fuel 21, and has a top plate 31, a bottom plate 32, and four wall plates 33 assembled in a box shape. The top plate 31 is located at the ceiling of the tank body 30, and the bottom plate 32 is located at the bottom of the tank body 30. The wall plates 33 are provided between the top plate 31 and the bottom plate 32 that face each other in the vertical direction, and are located at the side walls of the tank body 30. In the tank body 30 shown in FIG. 3, one of the four wall plates 33 is omitted, and only three wall plates 33 are shown.

[0023] A supply port 34 for fuel 21 is provided in the ceiling of tank body 30, and a delivery port 35 for fuel 21 is provided in the bottom of tank body 30. Supply port 34 is formed in top plate 31 and opens to a ceiling surface 36 inside tank body 30, which is the underside of top plate 31. A supply pipe 23 for supplying fuel 21 is attached to top plate 31 and connected to supply port 34. Delivery port 35 is formed in bottom plate 32 and opens to a bottom surface 37 inside tank body 30, which is the upper surface of bottom plate 32.

[0024] Fuel 21 is supplied into the tank body 30 from a supply port 34 located above the lid 40. Inside the tank body 30, the fuel 21 is stored between the lid 40 and a bottom surface 37. The fuel 21 is also discharged to the outside of the tank body 30 from a delivery port 35 located below the lid 40. The fuel 21 is delivered from the delivery port 35 toward the engine 12 and is supplied from the tank body 30 to the engine 12.

[0025] The lid 40 is made of polystyrene foam, a material with a lighter specific gravity than the fuel 21. When comparing masses per unit volume, the lid 40 is lighter than the fuel 21. Therefore, inside the tank body 30, the lid 40 floats on the surface of the fuel 21 due to buoyancy and is positioned between the fuel 21 and the air 22 inside the tank body 30. The lid 40 is a structure that covers the surface of the fuel 21 from above, and isolates the fuel 21 from the air 22 above it using a flat plate 50 and spherical bodies 60. FIG. 4 is a perspective view showing the flat plate 50 and spherical bodies 60 of the lid 40.

[0026] The flat plate 50, which is a plate body, is arranged along the surface of the fuel 21 inside the tank body 30. The surface of the fuel 21 is covered by the flat plate 50, which floats on the surface of the fuel 21 due to buoyancy. As shown in FIG. 3 , the flat plate 50 is arranged with a gap between it and the wall surface 38 of the wall panel 33, which is located inside the tank body 30. The flat plate 50 has a plurality of circular holes 51 spaced apart from one another, through which the fuel 21 can pass. The holes 51 have a circular shape in a cross section perpendicular to the thickness direction of the flat plate 50, and penetrate the flat plate 50 in the vertical direction. The fuel 21 passes through the holes 51 from the space above the flat plate 50 to the space below the flat plate 50.

[0027] Hole 51 is formed in a truncated cone shape with a diameter that gradually decreases toward the top. Therefore, the diameter of hole 51 gradually decreases from the lower surface of flat plate 50 toward the upper surface. Furthermore, the shape of the lower opening of hole 51 that opens on the lower surface of flat plate 50 and the shape of the upper opening of hole 51 that opens on the upper surface of flat plate 50 are both circular. The diameter of the lower opening of hole 51 is larger than the diameter of sphere 60, and the diameter of the upper opening of hole 51 is smaller than the diameter of sphere 60.

[0028] The lid 40 has spheres 60 in the same number as the holes 51 in the flat plate 50. The spheres 60 are arranged in different holes 51. Due to buoyancy, the spheres 60 enter the holes 51 from below and are pressed against the inner circumferential surfaces of the holes 51 from below. Figure 5 is a cross-sectional view showing the lid 40 when fuel 21 is stored in the tank body 30.

[0029] The sphere 60 is a spherical valve body that floats on the fuel 21 together with the flat plate 50 and fits into the hole 51 from below to close the hole 51. The sphere 60 comes into close contact with the inner circumferential surface of the hole 51 due to buoyancy, closing the hole 51. The sphere 60 blocks the fuel 21 from the air 22 at the location of the hole 51 in the flat plate 50. When the fuel 21 is supplied into the tank body 30, the fuel 21 is supplied from the supply port 34 to the upper side of the flat plate 50 and the sphere 60. FIG. 6 is a cross-sectional view showing the lid 40 when the fuel 21 is being supplied into the tank body 30.

[0030] When fuel 21 is supplied to the upper side of lid 40, sphere 60 is pushed downward by fuel 21. Due to the force received from fuel 21 above, sphere 60 moves away from the inner circumferential surface of hole 51, opening hole 51. Fuel 21 pushes sphere 60 aside, passes through hole 51, and reaches the underside of lid 40. After fuel 21 passes through hole 51, sphere 60 rises due to buoyancy to a position where it blocks hole 51, and closes hole 51 again.

[0031] As fuel 21 is supplied into and discharged out of tank body 30, the position of the surface of fuel 21 changes vertically inside tank body 30. Flat plate 50 and spheres 60 move vertically in accordance with the change in the position of the surface of fuel 21. When flat plate 50 moves vertically, it is guided vertically by guide 70, which is a guide rail shown in FIG. 3. FIG. 7 is a cross-sectional view of fuel tank 20 including a plan view of lid 40 as viewed from above.

[0032] As shown in Figures 3 and 7, the guides 70 are provided inside the tank body 30 and extend in the vertical direction between the ceiling surface 36 and the bottom surface 37 of the tank body 30. The guides 70 are provided on each of the four wall surfaces 38 inside the tank body 30 and protrude from the wall surfaces 38 toward the inside of the tank body 30. The flat plate 50 has four engagement portions 52 that engage with the guides 70 so as to be movable in the vertical direction. The guides 70 are disposed in the recessed engagement portions 52, and the engagement portions 52 move in the vertical direction along the guides 70.

[0033] The guide 70 engages with the flat plate 50 inside the tank body 30 and guides the flat plate 50 as it moves in accordance with changes in the surface position of the fuel 21. The flat plate 50 is maintained in a state along the surface of the fuel 21 without tipping over due to the guidance of the guide 70. As the fuel 21 is discharged out of the tank body 30, the flat plate 50 moves downward and comes into contact with stoppers 71, which are pillars. The stoppers 71 are provided on the bottom surface 37 of the tank body 30 and protrude upward from the bottom surface 37. Four stoppers 71 are arranged at positions adjacent to the four corners of the rectangular flat plate 50. Figure 8 is a cross-sectional view showing the lid body 40 and the tank body 30 with the flat plate 50 in contact with the stoppers 71.

[0034] After flat plate 50 comes into contact with stopper 71, when the surface of fuel 21 descends to a position below flat plate 50, sphere 60 moves downward from the position blocking hole 51. This opens hole 51, allowing fuel 21 to pass through hole 51. Furthermore, as the amount of fuel 21 decreases, sphere 60 comes into contact with bottom surface 37 of tank main body 30. Stopper 71 stops the downward movement of flat plate 50 and stops flat plate 50 in a state where sphere 60 comes into contact with bottom surface 37 and sphere 60 opens hole 51.

[0035] The flat plate 50 comes into contact with the upper end of the stopper 71 and stops. The height of the stopper 71 is the vertical distance from the bottom surface 37 of the tank body 30 to the upper end of the stopper 71, and is less than the diameter of the sphere 60. The upper part of the sphere 60 is positioned inside the hole 51 with a gap formed between it and the inner circumferential surface of the hole 51. The flat plate 50 is placed on the stopper 71 and is supported by the stopper 71. The flat plate 50 is held in a position spaced above the bottom surface 37.

[0036] The upper portion of sphere 60 is positioned within hole 51, thereby preventing sphere 60 from rolling along bottom surface 37 and separating from hole 51. Furthermore, a gap through which fuel 21 can pass is formed between sphere 60 positioned within hole 51 and the inner circumferential surface of hole 51. Fuel 21 supplied into tank body 30 passes through hole 51 and accumulates below lid 40. When the surface of fuel 21 rises to the position of flat plate 50, flat plate 50 floats on the surface of fuel 21 and moves upward away from stopper 71.

[0037] According to the first embodiment, for example, the following advantageous effects are achieved.

[0038] The lid 40 reduces the contact area between the fuel 21 and the air 22 inside the tank body 30, thereby suppressing oxidation of the fuel 21. Furthermore, by preventing contact between the fuel 21 stored in the tank body 30 and the air 22, deterioration of the fuel 21 can be suppressed. As a result, even when the fuel 21 is stored for a long period of time, the speed of deterioration of the fuel 21 due to oxidation can be slowed. When the fuel 21 is supplied into the tank body 30, the fuel 21 pushes aside the spheres 60, allowing the fuel 21 to be smoothly supplied to the underside of the lid 40.

[0039] Because the flat plate 50 is guided by the guides 70, the flat plate 50 can be stably moved up and down according to the surface position of the fuel 21. Furthermore, even if the fuel tank 20 moves while the hydraulic excavator 1 is in operation, the flat plate 50 can be stabilized and prevented from tipping over.

[0040] Because the stopper 71 stops the downward movement of the flat plate 50, the hole 51 is prevented from being blocked by the sphere 60 when the surface of the fuel 21 descends to a position below the flat plate 50. As a result, the hole 51 can be maintained in an open state. The fuel 21 supplied into the tank body 30 passes smoothly through the hole 51 from the upper side to the lower side of the lid 40. When the surface of the fuel 21 rises beyond the position of the flat plate 50, the flat plate 50 floats on the surface of the fuel 21 and moves upward. By providing the stopper 71 on the bottom surface 37 of the tank body 30, the stopper 71 can be easily provided inside the tank body 30.

[0041] The material of the lid 40 is not limited to polystyrene foam, and may be any material that floats on the surface of the fuel 21. The flat plate 50 and the sphere 60 may be made of different materials. Only one hole 51 may be provided in the flat plate 50, or multiple holes 51 may be provided in the flat plate 50. The hole 51 does not have to be a truncated cone-shaped hole, and may be, for example, a cylindrical hole. If the hole 51 is a cylindrical hole, the sphere 60 fits tightly against the lower opening of the hole 51 to close the hole 51.

[0042] (Second embodiment) 9 is a cross-sectional view showing a fuel tank 20 according to the second embodiment. Note that in the second embodiment, descriptions of parts common to the first embodiment will be omitted, and the description will focus on parts different from the first embodiment.

[0043] In the fuel tank 20 according to the second embodiment, a stopper 71 is provided to protrude from the lower end of the guide 70. The stopper 71 is formed integrally with the guide 70 and protrudes from the guide 70 toward the inside of the tank body 30. The lower end of the guide 70 and the stopper 71 are placed on the bottom surface 37 of the tank body 30.

[0044] According to the second embodiment, for example, the following advantageous effects are achieved.

[0045] The guide 70 is provided inside the tank body 30, and at the same time, the stopper 71 is disposed in a position where it can come into contact with the flat plate 50. Therefore, the stopper 71 can be easily provided inside the tank body 30. Also, an increase in the number of parts of the fuel tank 20 can be suppressed.

[0046] (Third embodiment) 10 is a cross-sectional view showing a lid 40 provided on a fuel tank 20 according to a third embodiment. In the third embodiment, descriptions of parts common to the first embodiment will be omitted, and the following description will focus on parts different from the first embodiment.

[0047] In the fuel tank 20 of the third embodiment, a hook portion 61 is connected to the sphere 60. The hook portion 61 is formed, for example, in a T-shape and protrudes upward from the sphere 60. The hook portion 61 also passes upward through the hole 51 and is disposed up to the upper side of the flat plate 50. The hook portion 61 hooks onto the upper surface of the flat plate 50 when the sphere 60 leaves the hole 51 open. The sphere 60 is engaged with the hole 51 by the hook portion 61 and is held in a position below the hole 51 where the hole 51 can be closed.

[0048] An upper piece portion 62 of the hook portion 61 is connected to the sphere 60 by a connecting portion 63 that extends through the hole 51, and is positioned above the flat plate 50. The hook portion 61 hooks onto the upper surface of the flat plate 50 by the upper piece portion 62 that abuts against the upper surface of the flat plate 50. The length of the upper piece portion 62 is longer than the diameter of the upper opening of the hole 51, and the width of the upper piece portion 62 is narrower than the diameter of the upper opening of the hole 51. In addition, the connecting portion 63 is narrower than the diameter of the upper opening of the hole 51. Therefore, the hole 51 is not blocked by the hook portion 61.

[0049] According to the third embodiment, for example, the following advantageous effects are achieved.

[0050] The catch 61 prevents the sphere 60 from moving away from the hole 51 due to the force received from the fuel 21 passing through the hole 51. Even if the flat plate 50 is stopped by the stopper 71 at a position above the sphere 60 as the surface of the fuel 21 descends, the sphere 60 can be held at the position of the hole 51 of the flat plate 50.

[0051] In the above-described embodiments, the present invention has been described as being applied to the fuel tank 20 of the hydraulic excavator 1, but the present invention can also be applied to fuel tanks of other types of work machines, including wheel loaders and dump trucks, and similar effects can be achieved. Furthermore, the present invention is not limited to fuel tanks of work machines, but can be applied to various types of fuel tanks.

[0052] The above-described embodiments are merely examples for explaining the present invention, and are not intended to limit the scope of the present invention to these embodiments. Those skilled in the art can implement the present invention in various other forms without departing from the spirit of the present invention. [Explanation of symbols]

[0053] 1. Hydraulic excavator 2 Undercarriage 3 Upper rotating body 4 Work equipment 12 Engine 20 Fuel Tank 21 Fuel 22 Air 30 Tank body 34 Supply port 35 outlet 36 Ceiling surface 37 bottom 38 Wall 40 Lid 50 flat plate 51 holes 52 Engagement portion 60 spheres 61 Hook 70 Guide (guide part) 71 Stopper

Claims

1. A fuel tank having a tank body for storing liquid fuel, a plate body having a circular hole formed therein and disposed in the tank body so as to float on the fuel; a sphere that fits into the hole from below and closes the hole while floating in the fuel.

2. 2. The fuel tank according to claim 1, a guide portion for guiding the plate member, which moves in accordance with changes in the surface position of the fuel, in the vertical direction within the tank body;

3. 3. The fuel tank according to claim 2, A fuel tank characterized in that it is provided with a stopper that stops the downward movement of the plate body when the sphere is in contact with the bottom surface of the tank body and the hole is opened by the sphere.

4. 4. The fuel tank according to claim 3, The fuel tank is characterized in that the stopper is provided on the bottom surface of the tank body and protrudes upward from the bottom surface.

5. 4. The fuel tank according to claim 3, The fuel tank is characterized in that the stopper is provided so as to protrude from a lower end of the guide portion.

6. 6. The fuel tank according to claim 1, The fuel tank is characterized in that the sphere has a hook portion that hooks onto the upper surface of the plate body when the hole is open.

Images