JP3914795B2 - Work machine and fuel supply device thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a work machine and a fuel supply apparatus thereof.
[0002]
[Prior art]
In general, a work machine is composed of a lower traveling body that controls the movement of the airframe, and an upper structure that is mounted on the lower traveling body and includes a driver's cab, an engine, etc., and is a fuel tank mounted on the upper structure. The fuel is supplied to the engine and driven.
[0003]
A hydraulic excavator as a typical example of this type of work machine will be described with reference to FIGS. 8 to 11. As shown in FIG. 8, the hydraulic excavator includes a lower traveling body 100, an upper swing body (upper structure) 200, and Is configured.
The upper swing body 200 includes a cab 220, a fuel tank 1, an engine 10, a power plant (not shown) for generating pressure oil, and the like on the swing frame 200a. It is attached to the traveling frame 100a of the body 100 so as to be able to turn. Further, a working arm mechanism 210 including a boom 211, an arm 212, a bucket 213, and cylinders 211a to 213a for swinging and driving the boom 211, the arm 212, and the bucket 213 is attached in front of the turning frame 200a, and pressure oil is supplied from the power plant. As a result, the cylinders 211a to 213a expand and contract, and the boom 211, the arm 212, and the bucket 213 swing.
[0004]
The lower traveling body 100 is configured as a crawler traveling body, and as shown in FIG. 11, left and right hydraulic motors 121 and 131 for traveling and a sprocket wheel that is connected to the hydraulic motors 121 and 131 and rotates forward or backward. 120, 130 and a crawler (not shown) wound around the sprocket wheels 120, 130.
[0005]
The hydraulic motors 121 and 131 are supplied with pressure oil from the power plant via the hydraulic pipes 122 and 132, and the operation and rotation direction of the hydraulic motors 121 and 131 are independently controlled. Then, the left and right hydraulic motors 121 and 131 rotate forward and backward simultaneously or alternately independently, so that the left and right crawlers wound around the sprocket wheels 120 and 130 independently rotate forward and backward. Backward, direction change is performed.
[0006]
The connecting portion 11 is provided with a swivel joint 111 communicating with the upper swing body 200 and the lower traveling body 100 at the center (the swing center of the upper swing body 200). The swivel joint 111 is provided on the upper swing body 200. In addition, hydraulic piping for supplying pressure oil from the power plant to the left and right hydraulic motors 121 and 131 of the lower traveling body 100 is provided.
[0007]
The swivel joint 111 is disposed so that its axis coincides with the rotation axis of the upper swing body 200, and is configured to include an inner cylinder 112 and an outer cylinder 113. The inner cylinder 112 is provided integrally with the upper swing body 200 and is freely inserted into the outer cylinder 113 so as to be freely rotatable. Pipes for supply and return oil are connected to the pressure oil control device of the power plant. ing. Further, the outer cylinder 113 is provided integrally with the lower traveling frame 100, and the hydraulic pipes 122, 132 are provided on the outer peripheral portion toward the rear of the lower traveling body (that is, the direction in which the sprocket wheels 120, 130 are provided). Is attached. The individual pipes are connected to pressure oil feed ports, drain ports, signal ports and the like of the left and right hydraulic motors 121 and 131, and the pressure oil pumped from the power plant is supplied to the supply pipe and inner cylinder 112. The pressure oil supplied to the feed port and the signal port via the drain port and discharged from the drain port is returned to the power plant via the reflux path.
[0008]
By the way, on the swivel frame 200a, together with the power plant, the fuel tank 1, and the cab 220, there are accessory devices for controlling and distributing power such as pressure oil generated in the power plant and performing various operations. It is installed all over. In addition to this, a sturdy bracket for attaching the work arm mechanism 210 at a predetermined position, a bonnet attached to the power plant, a control device, and turning actuators are arranged narrowly. Furthermore, in order to improve work performance, it is necessary to install a new device on the turning frame 200a, and the upper turning body 200 tends to increase in size.
[0009]
However, there is a limit to the outer dimensions of the upper swing body 200 due to the relationship between the size of the airframe and the operating capability of the machine. For this reason, recently, as disclosed in Japanese Patent No. 2566443, a hydraulic excavator has been proposed in which a part of the equipment on the turning frame 200a is moved to the lower traveling body 100 side.
In this hydraulic excavator, as shown in FIGS. 9 and 10, the fuel tank 1 is provided on the lower traveling body 100 side, and the upper revolving body 200 side is provided via a pipe line 8 passing through the swivel joint 111 in the connecting portion 11. Fuel is supplied to the engine 10 provided in the vehicle. In this way, by transferring the fuel tank 1 that is most likely to be transferred to the lower traveling body 100 in terms of the connection relationship between devices and efficiency, the empty space on the lower traveling body 100 side is reduced without reducing work performance. The arrangement of the devices on the revolving frame 200a can be made more effective and allow some space.
[0010]
[Problems to be solved by the invention]
As a method of supplying fuel from the fuel tank 1 arranged on the lower traveling body 100 side to the engine 10 provided on the upper swing body 200 side as described above, a suction pump is installed in the upper swing body 200 and the fuel tank is installed. A method of sucking up the fuel in the fuel tank 1 and a method of pumping the fuel in the fuel tank 1 to the engine 10 by installing a pressure pump on the lower traveling body 100 side are conceivable.
[0011]
However, when sucking with a suction pump, a large pump with a strong suction force is required, and there are problems in terms of cost and securing installation space.
On the other hand, in the case where a pumping pump is installed on the lower traveling body 100 side and the pumping is performed, an electrical wiring is provided in the swivel joint 111 to connect the pumping pump and the control device provided on the upper swing body 200 side. There is a need. In such an electrical wiring, it is necessary to have a structure that allows turning, such as by providing a slip ring, but in the swivel joint 111, a hydraulic supply pipe or engine for supplying pressure oil to the hydraulic motors 121 and 131 is required. Since the fuel supply pipe 8 for supplying the fuel is disposed and the hydraulic oil and fuel pass therethrough, special consideration is required.
[0012]
Further, in this case, since the fuel tank 1 has a negative pressure after the fuel is supplied, an air supply pipe is separately provided in the swivel joint 111 or the outside air is sucked from the cap 1a. It is necessary to maintain the inside of the tank 1 at normal pressure. However, the space in the swivel joint 111 is narrow, and it is difficult to install many pipes. Further, in this type of work machine, there is a case where the work is performed by immersing the water up to the upper part of the lower traveling body 100, and the fuel tank 1 needs to have a sealed structure.
[0013]
The present invention has been devised in view of the above-described problems, and a fuel supply device capable of supplying fuel with a simple configuration from a fuel tank installed in a lower traveling body to an engine installed in an upper structure, and It is an object of the present invention to provide a work machine having such a fuel supply device.
[0014]
[Means for Solving the Problems]
A fuel supply device for a work machine according to the present invention is applied to a work machine having an upper structure and a lower traveling body, and an engine is provided in the upper structure, and for storing fuel in order to achieve the above object. The main tank is provided in the lower traveling body, and a sub tank for supplying fuel to the engine is provided in the upper structure, and the main tank and the sub tank are connected to each other through a second pipe. Further, the air pump and the main tank are connected in communication via the first pipe line, and air is supplied from the air pump to the main tank.
[0015]
Therefore, the air pumped from the air pump flows into the main tank through the first pipe, and is accumulated above the fuel level stored in the main tank. The liquid level of the fuel stored in the main tank is pressurized by the pressure of the air accumulated in the main tank and brought into a high pressure state, and is pumped to the sub tank via the second pipe. Then, Ru thus the fuel stored in the sub tank is pumped from the main tank is supplied to the engine.
[0016]
Further , a first valve for regulating the flow of the first pipe line and a second valve for opening and closing the second pipe line are provided, and the pipe line on the main tank side of the first pipe line is connected to the second pipe line. so as to connect to the conduit of the main tank side of the second valve.
Thus, by operating the air pump with the first valve opened and the second valve closed, the air pumped from the air pump is sent to the main tank via the first pipe line and the second pipe line. It flows in and accumulates inside the main tank. Further, in the state where the inside of the main tank is sufficiently pressurized by the air accumulated in this way, the first valve is closed and the second valve is opened, so that the fuel passes through the second pipeline. It is transferred to the sub tank (Claim 1 ).
[0017]
Furthermore, at this time, the upper structure may be pivotably attached to the lower traveling body via the connecting portion, and the connection portion between the first pipe line and the second pipe line may be disposed in the upper structure body. (Claim 2 ).
Moreover, in order to achieve the said objective, the working machine of this invention is an upper structure, a lower traveling body, the engine provided in the upper structure, and the statement in any one of Claims 1-3. A fuel supply device for the work machine is provided (claim 3 ).
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a fuel supply device for a working machine as an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing the overall configuration, and FIGS. 2 to 5 are all for explaining the operation thereof. Both the schematic diagram, FIG. 6 and FIG. 7 are flowcharts for explaining the operation. In addition, the same code | symbol is attached | subjected about the site | part similar to the prior art demonstrated using FIGS. 8-11, and the description is partially abbreviate | omitted.
[0019]
As shown in FIG. 1, the working machine according to the present embodiment has a lower traveling body 100 and a connecting portion 11 on the lower traveling body 100 in the same manner as the conventional excavator described with reference to FIGS. 9 and 10. The upper revolving body (upper structure) 200 is mounted so as to be able to swivel through the engine, and is driven by the engine 10 provided in the upper revolving body 200.
[0020]
The fuel supply device for supplying fuel to the engine 10 includes a main tank 1, a sub tank 2 connected to the main tank 1 through a second pipe 8, an air pump 3, and a control device 20. It is configured with.
The main tank 1 is configured as a main tank for storing fuel for the engine 10 and is provided in the lower traveling body 100. Further, the main tank 1 is configured to be airtight and liquidtight so that inflow of sewage and the like from the outside is prevented.
[0021]
The sub tank 2 is configured to store a fixed amount of fuel for driving the engine 10, provided in the upper swing body 200, and connected to the main tank 1 through the second pipe 8. The fuel stored in the main tank 1 is transferred into the sub tank 2 via the second pipe 8 and is stored in the sub tank 2 by a certain amount. Further, the sub tank 2 is connected to the engine 10 via a fuel supply pipe 2 a so that the fuel stored in the sub tank 2 is stably supplied to the engine 10.
[0022]
In addition, a float sensor 9 is provided in the sub-tank 2, detects the amount of fuel stored in the sub-tank 2 based on the position of the sensor tip 9 a floating on the fuel, and outputs a detection signal to the control device 20. It is supposed to be. Specifically, when the sensor tip 9a falls below the attachment position of the sensor main body 9b, a fuel shortage state is detected. Conversely, when the sensor tip 9a exceeds the attachment position of the sensor main body 9b by a predetermined height, the full state (sub tank 2 is filled with a predetermined amount or more of fuel).
[0023]
As shown in FIGS. 1 to 5, the second pipe 8 is provided with a second valve (open / close valve) 5. By opening the second valve 5, the main tank 1 moves to the sub tank 2. The inflow of fuel can be prohibited by injecting fuel and closing the second valve 5.
The air pump 3 is for pumping air into the main tank 1, and is provided in the upper swing body 200, and is branched and connected from the second pipe 8 on the upstream side (the main tank 1 side) of the second valve 5. The main tank 1 is connected to the main tank 1 through the first pipeline 7. The air is accumulated in the main tank 1 by pressurizing the air into the main tank 1 through the pipe lines 7 and 8, and the inside of the main tank 1 is pressurized.
[0024]
The connecting portion between the first pipe line 7 and the second pipe line 8 is provided on the upper swing body 200 side, and the second pipe line 8 on the upstream side of the connecting portion is arranged in the connecting part 11. It is installed. Thereby, also in this structure which provided the air pump 3 in the upper revolving body 200, the piping arrange | positioned in the connection part 11 can be made into one, and the structure in the connection part 11 can be simplified now. Yes.
[0025]
In addition, an opening / closing valve (first valve) 4 is also provided in the first pipe line 7 so as to prevent fuel from flowing into the air pump 3.
Further, a pressure sensor 6 is provided in the first pipeline 7 so as to detect the pressure in the first pipeline 7 and output a pressure signal to the control device 20. The pressure sensor 6 detects the air pressure in the first pipe 7 by the air pump 3 and indirectly detects the pressure state in the main tank 1.
[0026]
The control device 20 is for controlling the operation of the air pump 3 and the opening / closing of the first valve 4 and the second valve 5. By combining the operation / stop of the air pump 3 and the opening / closing operation of the valves 4, 5, The amount of fuel transferred from the main tank 1 to the sub tank 2 can be adjusted by controlling the inflow direction and the inflow amount of fuel.
Specifically, when the sensor tip 9a of the flow sensor 9 falls below the attachment position of the sensor body 9b and detects that the sub tank 2 is in a fuel-deficient state, the first pipe line 7 is based on the pressure signal of the pressure sensor 6. When the fuel in the first pipe line 7 is pressurized to a predetermined pressure or higher, the second valve 5 is opened to transfer the fuel from the main tank 1 to the sub tank 2. To do.
[0027]
Conversely, when it is detected that the hydraulic pressure in the first pipe line 7 is smaller than the predetermined pressure or that the first pipe line 7 is not filled with fuel, the second valve 5 is closed and the air pump 3 is closed. Is activated. Thereafter, the first valve 4 is opened, air is pumped into the main tank 1 through the pipe lines 7 and 8, and the inside of the main tank 1 is pressurized. When it is detected from the pressure sensor 6 based on the pressure signal that the pressure in the main tank 1 is increased to a predetermined pressure or higher, the first valve 4 is closed and the air pump 3 is stopped. Stop pressurizing. Then, the second valve 5 is opened, and fuel is discharged into the sub tank 2.
[0028]
When the full state is detected by the float sensor 9, the second valve 5 is closed, and the transfer of fuel from the main tank 1 to the sub tank 2 is stopped.
Since the fuel supply device for a working machine according to an embodiment of the present invention is configured as described above, the control is performed according to the flow shown in FIGS. 6 and 7, for example, from the main tank 1 to the sub tank. The fuel is transferred to 2.
[0029]
First, when a fuel shortage state is detected by the flow sensor 9 in step S1, it is determined in step S2 whether or not the hydraulic pressure in the first conduit 7 is equal to or higher than a predetermined pressure based on the pressure signal of the pressure sensor 6. Is done. Here, when the hydraulic pressure is equal to or higher than the predetermined pressure, it is determined that the inside of the main tank 1 is in a high pressure state and the fuel can be transferred to the sub tank 2, and the process proceeds to step S4. If the hydraulic pressure is lower than the predetermined pressure or the first pipe 7 is not filled with fuel, it is determined that the fuel cannot be transferred, and the process proceeds to step S3. Then, the inside of the main tank 1 is pressurized by an in-tank pressurization routine as shown in FIG.
[0030]
That is, when the process proceeds to step S3, first, the second valve 5 is closed in step S31, and the inflow of air from the air pump 3 to the sub tank 2 is prohibited. In step S32, the air pump 3 is operated, and in step S33, the first valve 4 is opened. As a result, as shown in FIG. 2, the fuel remaining in the pipe lines 7 and 8 is returned to the main tank 1 by the air pressure, and air flows into the main tank 1 through the pipe lines 7 and 8. And accumulated above the fuel stored in the main tank 1. Then, the fuel in the main tank 1 is pressurized by the accumulated air that has become a high pressure state.
[0031]
In step S34, when the pressure sensor 6 detects that the air pressure in the first pipe line 7 is equal to or higher than the predetermined pressure, it is determined that the fuel can be transferred. In step S35, the first valve 4 is closed. In step S36, the operation of the air pump 3 is stopped (see FIG. 3). Thereby, the inside of the main tank 1 is kept in a sufficiently pressurized state.
[0032]
If it is determined in step S2 or step S34 that the fuel can be transferred, it is determined that the fuel can be transferred, and the second valve 5 is opened in step S4. As a result, the end of the second pipe line 8 on the sub tank 2 side is opened, and the fuel is pushed up to the sub tank 2 side through the second pipe line 8 by the pressure of the air in the main tank 1, and the fuel flows into the sub tank 2. Inflow (see FIG. 4).
[0033]
Then, when the fuel level in the sub tank 2 rises due to the inflowed fuel and the full state is detected by the float sensor 9 in step S5, the second valve 5 is closed in step S6, and the fuel is transferred to the sub tank 2. Is stopped (see FIG. 5).
In addition, after the 2nd valve 5 is closed and fuel transfer is stopped, the inside of the 2nd pipe line 8 is hold | maintained at the state filled with the pressurized fuel.
[0034]
Therefore, according to the fuel supply device for a working machine of the present embodiment, a required amount of fuel is transferred from the main tank 1 provided on the lower traveling body 100 side to the sub tank 2 provided on the upper swing body 200 side. Since the fuel stored in the engine 2 is supplied to the engine 10, the fuel supply to the engine 10 can be stably performed.
[0035]
Further, since the fuel is transferred from the main tank 1 to the sub tank 2 by a pressure feeding system, a large amount of power is not required for driving the pump, and the apparatus can be miniaturized. That is, air is supplied into the main tank 1 by the air pump 3, and the fuel level in the main tank 1 is pressurized by the pressure of the air accumulated in the main tank 1 and brought into a high pressure state, and pushed up to the sub tank 2 side. Since it is transported, medium and small pumps with relatively small pumping power can be used, and the cost can be reduced while simplifying the device configuration.
[0036]
Moreover, since the inside of the main tank 1 does not become a negative pressure, an intake structure such as taking in outside air through the cap 1a is unnecessary, and the main tank 1 can be formed into an airtight and liquid tight structure. Thereby, even when the operation of immersing the water up to the upper part of the lower traveling body 100 is performed, there is no possibility that the inside of the main tank 1 is contaminated.
Since the main tank 1 has an airtight structure as described above, the main tank 1 is kept in a high pressure state even after the fuel is transferred to the sub tank 2, and the fuel filled in the pipes 7 and 8 is stored in the main tank 1. It is never returned to 1. For this reason, the pipes 7 and 8 are always filled with fuel except when the air pump 3 pressurizes the main tank 1, and rusting in the pipes 7 and 8 is prevented and durability is improved. Can be improved.
[0037]
Further, the second pipe 8 and the first pipe 7 are connected on the upstream side of the second valve 5, and the second pipe 8 on the upstream side of the connection portion between the first pipe 7 and the second pipe 8. Can be used as both a fuel transfer path and an air supply path, so that the piping structure can be simplified and one fuel transfer pipe disposed in the swivel joint 111 (that is, the fuel transfer path and the air supply path). Only the second pipe line 8 on the upstream side of the connecting portion that is also used as the above-described connecting portion, and the configuration inside the swivel joint 111 can be simplified.
[0038]
Moreover, the air pump 3 can be provided in the upper turning body 200 side by providing the connection part of the 1st pipe line 7 and the 2nd pipe line 8 in the upper turning body 200 side. Thereby, it is not necessary to provide the electrical wiring for connecting the air pump 3 and the control apparatus 20 in the connection part 11, and the structure of the swivel joint 111 can further be simplified.
In addition, this invention is not limited to the above-mentioned embodiment, It can implement in various deformation | transformation in the range which does not deviate from the meaning of this invention.
[0039]
For example, the first pipeline 7 is directly connected to the main tank 1 without being connected to the second pipeline 8, and the fuel transfer channel (second pipeline 8) and the air supply channel (first pipeline 7) are separated. You may comprise. In this case, the air pumped from the air pump 3 is directly accumulated in the main tank 1 without passing through the fuel, and the fuel level is pressurized.
The first valve 4 is configured as a check valve that restricts the flow of fuel from the main tank 1 side to the air pump 3 side and allows only the air flow from the air pump 3 side to the main tank 1 side. Also good.
[0040]
【The invention's effect】
As described above in detail, according to the present invention, the required amount of fuel is transferred from the main tank provided in the lower traveling body to the sub tank provided in the upper swing body, and the fuel stored in the sub tank is transferred to the engine. Since it supplies, the fuel supply to an engine can be performed stably.
[0041]
In addition, air is supplied into the main tank by an air pump, and the fuel level in the main tank is pressurized by the pressure of the air accumulated in the main tank and brought into a high pressure state, and is pushed up and transferred to the sub tank side. Therefore, a medium / small pump having a relatively small pumping force can be used, and the cost can be reduced while simplifying the device configuration.
[0042]
Moreover, since the inside of the main tank does not become negative pressure, an intake structure such as taking in outside air into the main tank is unnecessary, and the main tank can be made into an airtight and liquid tight structure. Accordingly, even when subjected to working such as immersed in water to the top of the lower traveling body, a fear is not a name that the main tank is contaminated.
In addition, the main tank side pipe line of the first pipe line and the main tank side pipe line of the second pipe line are connected, and the first valve and the second pipe are respectively provided with the first valve and the second valve. By controlling the opening and closing of each valve, the second pipe upstream of the connection between the first pipe and the second pipe can be used as the fuel transfer path and the air supply path, simplifying the piping structure Can be In this case, when the second valve is closed after the fuel is transferred from the main tank to the sub tank, the main tank is maintained in a high pressure state, and the fuel filled in the first and second pipes is It will not be returned to the main tank. For this reason, the inside of the first and second pipes is always filled with fuel except when the inside of the main tank is pressurized by an air pump, and the occurrence of rust in the pipes is prevented and durability is improved. (Claims 1 and 3 ).
[0043]
At this time, the upper structure is pivotally attached to the lower traveling body by the connecting portion, and the connection portion between the first pipe line and the second pipe line is disposed on the upper turning body side with respect to the connecting portion. Thus, the air pump can be provided on the upper swing body. Thereby, it is not necessary to provide the electric wiring for air pump operation in a connection part, and the structure in a connection part can be simplified. In addition, the fuel transfer pipe disposed in the connecting portion can be only the second pipe upstream of the connecting portion, which is also used as the fuel transfer passage and the air supply passage. Can be further simplified (claims 2 , 3 ).
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an overall configuration of a fuel supply device for a working machine according to an embodiment of the present invention.
FIG. 2 is a schematic diagram for explaining the operation of a fuel supply device for a working machine according to an embodiment of the present invention.
FIG. 3 is a schematic diagram for explaining the operation of the fuel supply device for the working machine according to the embodiment of the present invention.
FIG. 4 is a schematic diagram for explaining the operation of a fuel supply device for a working machine according to an embodiment of the present invention.
FIG. 5 is a schematic diagram for explaining the operation of the fuel supply device for the working machine according to the embodiment of the present invention.
FIG. 6 is a flowchart for explaining the operation of the fuel supply device for the working machine according to the embodiment of the present invention.
FIG. 7 is a flowchart for explaining the operation of the fuel supply device for the working machine according to the embodiment of the present invention.
FIG. 8 is a diagram showing an overall configuration of a conventional work machine.
FIG. 9 is a diagram showing an overall configuration of a conventional work machine.
FIG. 10 is a diagram illustrating an overall configuration of a conventional fuel supply device for a work machine.
FIG. 11 is a schematic diagram showing a structure of a lower traveling body of a conventional work machine.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Main tank 2 Sub tank 3 Air pump 4 1st valve 5 2nd valve 7 1st pipe line 8 2nd pipe line 10 Engine 11 Connection part 20 Control apparatus (control means)
100 Lower traveling body 200 Upper structure (upper turning body)

Claims (3)

In a working machine that includes an upper structure and a lower traveling body, and the engine is provided in the upper structure, a fuel supply device that supplies fuel to the engine,
A main tank provided in the lower traveling body for storing fuel;
A sub tank provided in the upper structure and supplying fuel to the engine;
An air pump,
A first pipe connecting the air pump and the main tank in communication;
A second pipe for connecting the main tank and the sub tank in communication, and capable of supplying fuel in the main tank to the sub tank ;
A first valve that regulates the flow of the first pipe;
A second valve for opening and closing the second pipe line;
A fuel supply for a work machine, wherein the main tank side pipe line of the first pipe line is connected to the main tank side pipe line rather than the second valve of the second pipe line apparatus. The upper structure is pivotably attached to the lower traveling body via a connecting portion,
Connection between the first conduit and the second conduit is characterized in that it is arranged on the superstructure, the working machine of the fuel supply apparatus according to claim 1. A superstructure;
A lower traveling body,
An engine provided in the upper structure;
Characterized in that a fuel supply device for a working machine according to claim 1 or 2, wherein the work machine.

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