JPH08134954A - Fuel tank of construction machine - Google Patents

Abstract

PURPOSE: To make a tank main body large by utilizing a dead space in a machine house by supplying almost total amount of fuel filled in the tank main body to an engine, even if a vehicle is inclined in any direction. CONSTITUTION: Two fuel supply pipes 22a, 22b are connected to positions at substantially both ends in the longitudinal direction on a bottom surface of a main body 21 of a fuel tank 20, and they are merged into a fuel supply main pipe 24 by a pipe joint 23 at the intermediate position of a connection section to the tank main body 21 to supply fuel to an engine. If a vehicle is inclined to the right or left, the fuel tank 20 is also inclined in these directions. However, as the dimension in these directions is short, fuel can be supplied to the engine until almost all fuel in the tank main body 21 runs out. Also, when a vehicle is inclined forward or backward, the majority of the fuel in the tank main body 21 can be supplied to the engine because either of the fuel supply pipes is positioned below liquid level and the pipe joint 23 is at the intermediate position between both fuel supply pipes 22a, 22b and at the position lower than the bottom surface of the tank main body 21 by an interval d.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel tank, such as a hydraulic excavator, which is installed in a construction machine for working not only on a flat ground but also on a sloping ground and supplies fuel to an engine.

[0002]

2. Description of the Related Art A typical construction machine is a hydraulic excavator shown in FIG. In the figure, 1 is a lower traveling structure, 2 is an upper revolving structure installed on the lower traveling structure 1 so as to be swingable, and an operator cab 3 and a boom 4 are provided on the upper revolving structure 2.
A front working mechanism 4 including a, an arm 4b, and a bucket 4c as a front attachment is attached. Further, the upper swing body 2 is provided with a machine room 5 behind the operator's cab 3.

A hydraulic excavator uses a hydraulic actuator such as a hydraulic motor or a hydraulic cylinder as an actuator. A hydraulic pump is used to supply the hydraulic oil to this hydraulic actuator, and the hydraulic oil is supplied from the hydraulic oil tank to the hydraulic pump. Supplied to the actuator. An engine is provided to drive the hydraulic pump, and a fuel tank is also provided to supply fuel to the engine. These engines, hydraulic pumps,
Various devices such as a direction switching valve, a hydraulic oil tank, a fuel tank, etc. are mounted in the machine room 5.

Therefore, FIGS. 6 and 7 show an example of the arrangement of the above-mentioned devices in the machine room 5. In the figure,
Reference numeral 10 is an engine, 11 is a radiator, 12 is a hydraulic pump, 13 is a hydraulic oil tank, 14 is a directional control valve unit, and 15 is a fuel tank. For these various devices, for example, the radiator 11 is the engine 1
In order to efficiently circulate the cooling air through the engine 10, other devices cannot be placed in the passage of the cooling air. There are certain restrictions on the mutual positional relationship, etc. Also, considering repairability, inspection and other maintainability, it is necessary to provide a certain distance between each device.
In addition, the engine 10, the radiator 11, the hydraulic pump 12
In some cases, the shape of the directional control valve unit 14 and the like is fixed because of its structure. Therefore, it is quite difficult to rationally arrange these various types of equipment within the limited space of the machine room 5, and despite the limited space, a dead space is still created. .

[0005]

Among the devices installed in the machine room 5, the fuel tank 15 is a container filled with fuel, so that the shape is not always limited as long as a predetermined internal volume is secured. It is not something that will be done. Therefore, if the dead space in the machine room is used in consideration of the relationship between the space in the machine room and the arrangement of other devices, the fuel tank 1
5 can be enlarged. For example, in the case of the arrangement configuration shown in FIG. 7, it is possible to extend in the direction indicated by a virtual line in the figure, that is, the front-rear direction of the vehicle. That is, in order to increase the size of the fuel tank 15 in the direction in which it projects into the dead space, the fuel tank 15 usually has an elongated shape.

By the way, a work site where a construction machine such as a hydraulic shovel operates operates not only on a flat ground but also on a sloping ground. On the sloping ground, the fuel tank 15 also naturally tilts, and when the remaining amount of fuel is small,
When the fuel tank 15 is tilted in the vertical direction, a considerable amount of fuel cannot be delivered depending on the connection position of the fuel supply pipe from the fuel tank 15, and the internal volume of the fuel tank 15 is apparently small. Although it is large, there is a problem in that the amount of fuel that can actually be used may not always be commensurate with it. Above all, the operator who operates the hydraulic excavator, etc. checks the fuel gauge before starting work and starts the actual work, but when moving to a sloping ground with a considerable angle and working, a considerable amount of fuel still remains. Despite remaining in the tank 15, it becomes impossible to supply fuel to the engine at an early stage, and in a serious case, there is a possibility that the vehicle suddenly stops due to an unbalanced inclination state. . From the above, it is impossible to increase the internal volume of the fuel tank 15 simply by enlarging it in the dead space in the machine chamber.

Therefore, according to the present invention, most of the fuel in the fuel tank can be reliably supplied to the engine even in a tilted state, and the internal volume of the elongated fuel tank can be substantially increased. It is an object.

[0008]

In order to achieve the above-mentioned object, the present invention is a fuel tank installed on an upper swing structure for supplying fuel to an engine of a construction machine. A characteristic is that the tank main body for storing is formed in an elongated shape, a fuel supply pipe is connected near both ends in the longitudinal direction, and these two pipe connection parts are joined at a substantially central portion of the lower part of the tank main body. To do.

[0009]

When working on a sloping ground, the tank main body of the fuel tank inclines. If this inclination direction is the lateral direction of the tank main body, no matter where the fuel supply pipe is connected, Most fuel can be supplied from the tank body. However, in the case where the longitudinal direction of the inclination direction of the tank main body is up and down, the fuel is biased downward, so that a considerable amount of fuel cannot be supplied depending on the connection position of the fuel supply pipe. However, since the fuel supply pipes are connected near both ends in the longitudinal direction of the tank body, at least one of the fuel supply pipes is positioned below the liquid level even if the fuel supply pipes are inclined vertically in the longitudinal direction. So
Fuel can be supplied.

The two fuel supply pipes join together on the way, but depending on the joining position and the inclination direction, even if the fuel supply pipes are connected near both ends in the longitudinal direction, the joining position is below the liquid surface. Then, the fuel cannot be supplied any more. Therefore, the two fuel supply pipes are made to join at the lower center of the tank main body at the substantially central portion. As a result, the merging portion is almost never above the liquid surface at an inclination angle in a normal working state, even when the vehicle is extremely inclined to such an extent that the stability of the vehicle is impaired. As a result, by using the elongated rectangular fuel tank, the fuel in the fuel tank can be fully used regardless of the direction in which the vehicle is inclined.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 and 2 show the schematic structure of the fuel tank. The fuel tank 20 has a tank main body 21, and the tank main body 21 is filled with fuel. Whether the outer shape of the tank body 21 is a cylinder or a cube, in order to utilize the dead space shown in FIG. 7, the tank body 21 is extended in a direction indicated by an imaginary line,
The inner volume of the tank main body 21 is increased by making the vehicle body longer in the front-rear direction of the traveling direction than that of the conventional art.

Two fuel supply pipes 22a and 22b are connected to the tank main body 21, and these two fuel supply pipes 22a and 22b are located on the lower surface of the tank main body 21 at substantially both ends in the longitudinal direction thereof. Is connected to the position. And these two fuel supply pipes 22a and 22b
Are joined by a pipe joint 23 and supplied to the engine as a fuel supply main pipe 24. here,
The merging point of the fuel supply pipes 22a and 22b by the pipe joint 23 is provided at a lower position of the tank main body 21 at a substantially intermediate position of a connecting portion of the fuel supply pipes 22a and 22b to the tank main body 21. In the figure, 25
Is a vehicle body frame in which the tank body 21 is installed.

The present embodiment is constructed as described above, and the tank main body 21 of the fuel tank 20 is the same as that of the prior art without changing other devices arranged in the machine room and their arrangement. The size of the tank body 21 is larger than that of the one shown by the phantom line in FIG.
The amount of fuel that can be filled inside is increased accordingly. Therefore, the number of times of refueling can be reduced by the increased amount of this fuel.

By the way, construction machines such as hydraulic excavators sometimes work not only on flat ground but also on sloping ground, and they may tilt in the front-rear and left-right directions of the vehicle. Accordingly, the liquid level inside the tank body 21 of the fuel tank 20 fluctuates back and forth and left and right. A fuel gauge is provided in the operator's cab, and this fuel gauge detects the liquid level in the tank body 21 and displays the remaining fuel amount. However, the remaining fuel amount displayed by this fuel gauge is merely the amount of fuel remaining in the tank body 21, that is, the amount that can be supplied to the engine in a state where the fuel level is substantially horizontal. When the vehicle tilts and the liquid level in the tank body 21 fluctuates, it is possible that some of the fuel cannot be supplied depending on the connection position of the fuel supply pipe.

Normally, the operator checks the amount of fuel remaining with a fuel gauge before starting work, but when there is almost no remaining amount of fuel, refueling is performed, so this is not a problem, but in relation to the work,
When the fuel required for the work remains, the work may be started as it is. However, if the work site is a sloping ground, the tank body 21 will be tilted, and the lower surface of the tank body 21 will be partially exposed. If the fuel supply pipe is connected only to the exposed portion of the lower surface of the tank body 21, the fuel supply to the engine is stopped after the fuel in the fuel supply pipe is used up. Will be done.

When the vehicle leans to the left and right, the fuel tank 20
Although the tank main body 21 has a short dimension in the left-right direction of this vehicle, even if the tank main body 21 is slightly inclined in this direction, the fuel supply pipes 22a and 22b are filled with fuel until the fuel in the tank main body 21 is almost exhausted. It is kept in a state of being located below the liquid surface. Therefore, almost all of the fuel in the tank body 21 can be supplied to the engine.

When going up and down a slope,
When the vehicle leans back and forth, the tank body 21 of the fuel tank 20 leans as shown in FIG. 3 or 4. Due to the lengthening of the tank body 21 in order to make it larger, if the tank body 21 is tilted to a certain extent, the liquid level will be biased downward and the lower surface of the tank body 21 will be even if a considerable amount of fuel remains. Part is exposed. However, since the two fuel supply pipes 22a and 22b are connected to positions near both ends in the longitudinal direction of the tank main body 21, even if the fuel cannot be supplied on one fuel supply pipe side, the other The fuel supply pipe can be held at a position below the liquid level, and the fuel can be delivered through the fuel supply pipe below the liquid level.

Here, the two fuel supply pipes 22a, 22
When b is connected to the engine separately, the number of pipes increases and the structure for connecting to the engine becomes complicated. Therefore, the fuel supply pipes 22a, 22a
b is joined by using the pipe joint 23 on the way. Therefore, if the vehicle is tilted until the pipe joint 23 is positioned above the horizontal plane including the liquid surface of the fuel in the tank body 21, the fuel cannot be supplied again. However, the pipe joint 23 is located at a substantially intermediate position between the fuel supply pipes 22a and 22b, and is located below the lower surface of the tank body 21 by the distance d. Therefore, even if the vehicle is considerably inclined, the pipe joint 23 is not located above the liquid level in the tank body 21. Generally, in hydraulic excavators and other construction machines, the maximum tilt angle at which work can be performed safely on sloping ground is fixed, and there is also a restriction on the tilt angle due to the structure of the oil pan for supplying engine lubricating oil. Therefore, the maximum inclination angle of the vehicle is determined. For example, in a large hydraulic excavator, the maximum tilt angle is 30
°, and in the case of a medium-sized hydraulic excavator, 35 °
It has become a degree. Therefore, the fuel supply pipes 22a, 22
The distance d may be set so that the angle θ (see FIG. 1) of the surface connecting b and the pipe joint 23 with respect to the horizontal plane has at least this maximum inclination angle or more.

As described above, even if the tank body 21 of the fuel tank 20 is inclined so that the longitudinal direction of the tank body 21 is vertical, the tank cannot be actually supplied to the engine as indicated by the diagonal lines in FIGS. 3 and 4. The amount of fuel remaining in the main body 21 is extremely small as compared with the case where the fuel supply pipe is connected to the central portion in the longitudinal direction of the tank main body 21, as shown by the phantom line in FIG. The internal volume of the main body 21 can be substantially increased, and although the fuel remains in the tank main body 21, this residual fuel cannot be supplied to the engine, and the vehicle is unstable in a sloped state. It is possible to reliably prevent the occurrence of a situation such as sudden stop.

In the above-described embodiment, the fuel tank elongated in the front-rear direction of the vehicle is used based on the layout of each device in the machine room shown in FIG. The arrangement of the devices is not always this way. For example, if there is a space for projecting the fuel tank in the left-right direction, the tank main body can be formed in a shape elongated in this direction.

[0021]

Since the present invention is constructed as described above, it is possible to supply almost the entire amount of fuel filled in the tank body to the engine, no matter which direction the vehicle is inclined. Therefore, by effectively utilizing the dead space in the machine room, the tank main body is extended so as to project into the dead space, and the fuel tank can be increased in size regardless of the arrangement of other devices. Play.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of a fuel tank showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an operation explanatory view showing a state where the fuel tank is inclined in one direction.

FIG. 4 is an operation explanatory view showing a state where the fuel tank is inclined in another direction.

FIG. 5 is an external view of a hydraulic excavator as an example of a construction machine.

FIG. 6 is a perspective view of essential parts showing a state in which a machine room cover of the construction machine is removed.

FIG. 7 is an arrangement configuration diagram of a machine room of the hydraulic excavator.

[Explanation of symbols]

 20 Fuel Tank 21 Tank Main Body 22a, 22b Fuel Supply Pipe 23 Pipe Joint 24 Fuel Supply Main

Claims (1)

[Claims] 1. A fuel tank installed on an upper structure for supplying fuel to an engine of a construction machine,
The tank main body for storing the fuel is formed in an elongated shape, the fuel supply pipes are connected near both ends in the longitudinal direction, and these two pipe connecting portions are joined at a substantially central portion of the lower portion of the tank main body. Fuel tank for construction machinery.