JP2010007487A - Fuel circuit of fully slewing work vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel circuit of a fully slewing work vehicle capable of reducing the number of the ports of a swivel joint and suppressing the rise of the temperature of the fuel supplied to an engine. <P>SOLUTION: This fuel circuit is provided at a wheel shovel having a traveling body 1, a slewing body 2 disposed at the traveling body 1, and a swivel joint 7 interposed between the traveling body 1 and the slewing body 2. The fuel circuit includes the engine 4 disposed in the engine compartment 2b of the slewing body 2, a feed pump 5 disposed at the traveling body 1 for discharging fuel supplied to the engine 4, a fuel tank 6 disposed at the traveling body 1 for storing the fuel sucked into the feed pump 5, a supply pipe 8 which is connected to the feed pump 5 which extends to the slewing body 2 through the swivel joint 7, and supplies the fuel to the engine 4, and a return pipe 9 for returning the unburned fuel not burnt in the engine 4. The return pipe 9 is connected to a portion of the supply pipe 8 which is positioned at the downstream side of the swivel joint 7. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel circuit for an all-swivel work vehicle that is provided in a fully-turning work vehicle such as a wheel excavator and that has a feed pump that supplies fuel to an engine that is placed on the turning body.

There exists a thing shown by patent document 1 as this type of prior art. This prior art is, for example, a fuel circuit provided in a wheel excavator, and the wheel excavator includes a traveling body, a revolving body disposed on the traveling body, and a swivel joint interposed between the traveling body and the revolving body. It has. The fuel circuit includes an engine disposed in the revolving body, a feed pump disposed in the traveling body and discharging fuel supplied to the engine, and a fuel tank disposed in the traveling body and storing fuel sucked into the feed pump. Yes. In addition, a supply line connected to the feed pump and extending through the swivel joint to the swivel body to supply fuel to the engine, and a return line for returning unburned fuel not burned by the engine to the fuel tank through the swivel joint I have.
Japanese Patent Publication No. 7-99127

  In the above-described prior art, in order to return the unburned fuel to the fuel tank, the return pipe is configured to pass through the swivel joint interposed between the traveling body and the swivel body. There is a problem that the number is increased, and the structure of the swivel joint is complicated, resulting in an increase in manufacturing cost.

  In addition to the fuel supplied to the engine flowing through the swivel joint, the high-temperature unburned fuel returned from the engine and the driving oil for driving the driving motor and the brake having relatively high temperatures flow. For this reason, in the prior art, the fuel supplied to the engine at the swivel joint is heated by the high-temperature unburned fuel and the hydraulic oil having a relatively high temperature, and the temperature is likely to rise. As described above, there is a concern that the fuel efficiency of the engine is lowered when the fuel whose temperature is increased by heating is supplied to the engine.

  The present invention has been made from the above-described prior art, and an object of the present invention is to make a swivel joint that can reduce the number of ports of a swivel joint and suppress an increase in the temperature of fuel supplied to the engine. It is to provide a fuel circuit for a work vehicle.

  In order to achieve the above object, a fuel circuit for an all-swivel work vehicle according to the present invention includes a traveling body, a revolving body disposed on the traveling body, and the traveling body and the revolving body. An engine disposed in the revolving structure, a feed pump disposed in the traveling body and discharging fuel supplied to the engine, and the traveling body. A fuel tank that stores fuel sucked into the feed pump, a supply line that is connected to the feed pump and extends through the swivel joint to supply the fuel to the engine, and the engine In a fuel circuit of a fully swivel work vehicle having a return line for returning unburned unburned fuel, the return line is connected to the swivel joint. It is a configuration that is connected to the supply pipe portion located in the flow.

  In the present invention configured as described above, since the return line is connected to the supply line portion located downstream of the swivel joint, it is not necessary to provide a return line that passes through the swivel joint. The number can be reduced. Further, since it is not affected by the high-temperature unburned fuel returned from the engine or the relatively high-temperature hydraulic oil flowing through the swivel joint, the temperature rise of the fuel supplied to the engine can be suppressed.

  The fuel circuit of the all-turn work vehicle according to the present invention is characterized in that, in the above-described invention, the fuel circuit includes a heat exchanger that cools the unburned fuel that is returned from the return pipe and has a high temperature.

  In the present invention configured as described above, the temperature of the high-temperature unburned fuel led to the return line is lowered by the heat exchanger, and the unburned fuel whose temperature has been lowered joins the fuel discharged from the feed pump. To do. Therefore, the temperature of the merged fuel supplied to the engine can be lowered.

  Moreover, the fuel circuit of the all-swivel work vehicle according to the present invention is characterized in that, in the above invention, the heat exchanger is disposed in the return pipe.

  In the fuel circuit of the all-swivel work vehicle according to the present invention, in the above invention, the heat exchanger is disposed in the supply line portion located downstream of the connection point between the supply line and the return line. It is characterized by the arrangement.

  In the present invention configured as described above, the temperature of the high-temperature unburned fuel guided to the return pipe can be lowered, and the temperature of the fuel discharged from the feed pump can be lowered by the heat exchanger. Therefore, the temperature of the merged fuel supplied to the engine can be more reliably lowered.

  Further, in the fuel circuit of the all-turn work vehicle according to the present invention, in the above invention, one end is connected to the return line, and the other end is connected to the supply line portion located downstream of the heat exchanger. And a relief valve that opens and closes according to the viscous resistance of the unburned fuel led to the return line is disposed in the branch line.

  The present invention configured as described above is a viscous resistance of unburned fuel when the temperature of the unburned fuel returned from the engine to the return line is relatively low, such as when the engine is started in a low-temperature working environment. The relief valve is opened by the increase of, and the unburned fuel returned to the return line is guided from the branch line to the supply line through the relief valve. That is, the unburned fuel returned to the return line is led to the supply line without passing through the heat exchanger, and merges with the fuel discharged from the feed pump. Further, when the temperature of the unburned fuel returned from the engine to the return line becomes high, the viscosity resistance of the unburned fuel is reduced, so that the relief valve is held closed, and the unburned fuel is separated from the branch line. Without being led to the heat exchanger, it is led to the supply pipe line portion located upstream of the heat exchanger and merges with the fuel discharged from the feed pump, and the joined fuel is cooled in the heat exchanger. Therefore, at the time of start-up in a low-temperature working environment, the unburned fuel guided to the return line having a relatively low temperature can be warmed without passing through the heat exchanger, thereby smoothly starting the engine. be able to.

  Since the present invention connects the return line to the supply line part located downstream of the swivel joint interposed between the traveling body and the swivel body, the number of ports of the swivel joint can be reduced, The structure of the swivel joint can be simplified, and the production cost can be made lower than before. In addition, since it is not affected by the high-temperature unburned fuel returned from the engine or the relatively high-temperature hydraulic fluid flowing through the swivel joint, it is possible to suppress the temperature rise of the fuel supplied to the engine. In comparison, the combustion efficiency of the engine can be improved.

  In addition, if a heat exchanger is provided to cool the unburned fuel that has been returned from the return pipe and the temperature has risen, the temperature of the combined fuel supplied to the engine can be lowered, and the combustion efficiency of the engine can be reduced. It can be further increased.

  The best mode for carrying out the fuel circuit of the all-turn work vehicle according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a side view showing a wheel excavator cited as an example of an all-swivel work vehicle provided with each embodiment of the fuel circuit according to the present invention.

  As shown in FIG. 1, a wheel excavator provided with each embodiment of the fuel circuit according to the present invention is disposed on a traveling body 1 having a wheel 1a, and a driver's cab 2a and an engine compartment 2b. And a revolving unit 2 having a counterweight 2c, and a front work machine 3 attached to the revolving unit 2 so as to be rotatable in the vertical direction. The front work machine 3 includes a boom 3a attached to the swing body 2 so as to be rotatable in the vertical direction, an arm 3b attached to the tip of the boom 3a, and a bucket 3c attached to the tip of the arm 3b. Yes. A swivel joint is disposed between the traveling body 1 and the swivel body 2 to allow insertion of piping or the like extending between the traveling body 1 and the revolving body 2.

  FIG. 2 is a circuit diagram showing a first embodiment of a fuel circuit according to the present invention. As shown in FIG. 2, the fuel circuit according to the first embodiment discharges the fuel supplied to the engine 4 and the engine 4 disposed in the engine body 2 b of the revolving structure 2 and the traveling body 2. And a fuel tank 6 that stores fuel that is disposed in the traveling body 2 and is sucked into the feed pump 5. Further, a supply pipe 8 connected to the feed pump 5 and extending through the swivel joint 7 to the swivel body 2 for supplying fuel to the engine 4 and a return pipe for returning unburned fuel not burned by the engine 4 Road 9 is provided. The return line 9 is connected to the supply line 8 located downstream of the swivel joint 7.

  A filter 10 for removing dust and the like in the fuel is disposed in the supply line 8, and a fuel in the direction of the engine 4 from the supply line 8 side through the return line 9 side is provided in the return line 9. A check valve 11 is arranged to prevent the backflow. The feed pump 5 is driven by a motor 13. Further, the fuel circuit according to the first embodiment includes a heat exchanger 12 that cools the unburned fuel that has been returned from the return pipe 9 and whose temperature has increased. This heat exchanger 12 is disposed in the return line 9, for example.

  In the first embodiment configured as described above, when the motor 13 is driven, the feed pump 5 is operated, and the fuel discharged from the feed pump 5 is guided to the supply conduit 8 inserted through the swivel joint 7. , Supplied to the fuel injection portion of the engine 4. As a result, the engine 4 is driven, and a hydraulic pump (not shown) is operated by driving the engine 4. The traveling of the traveling body 1, the turning of the revolving body 2, or the driving of the front work machine 3 is performed by the pressure oil discharged from the hydraulic pump. Excavation work such as earth and sand is performed by driving the front working machine 3.

  Unburned fuel that has not been burned by the engine 4 is guided to the supply line 8 by the return line 9, merges with the fuel discharged from the feed pump 5, and is used again as fuel for the engine 4.

  In addition, the temperature of the high-temperature unburned fuel led to the return line 9 is lowered by the heat exchanger 12 arranged in the return line 9, and the unburned fuel thus lowered in temperature is fed from the feed pump 5. Merges with discharged fuel. Therefore, the temperature of the merged fuel supplied to the engine 4 can be lowered.

  According to the first embodiment configured as described above, since the return pipe 9 is connected to the supply pipe 8 located downstream of the swivel joint 7, the number of ports of the swivel joint 7 can be reduced. As a result, the structure of the swivel joint 7 can be simplified, and the production cost can be reduced. Further, since it is not affected by the high-temperature unburned fuel returned from the engine 4 or the relatively high-temperature hydraulic fluid flowing through the swivel joint 7, the temperature rise of the fuel supplied to the engine 4 can be suppressed. As a result, the combustion efficiency of the engine 4 can be improved.

  Further, the temperature of the high-temperature unburned fuel led to the return line 9 is lowered by the heat exchanger 12 arranged in the return line 9, and the unburned fuel whose temperature has been lowered is discharged from the feed pump 5. To join the fuel. Therefore, the temperature of the merged fuel supplied to the engine 4 can be lowered, and the combustion efficiency of the engine 4 can be further increased.

  FIG. 3 is a circuit diagram showing a second embodiment of the fuel circuit according to the present invention. In the second embodiment shown in FIG. 3, the heat exchanger 12 that cools the unburned fuel that has been returned from the engine 4 and has a high temperature is disposed downstream of the connection point between the supply line 8 and the return line 9. Thus, it is arranged in the supply pipe 8 portion located upstream of the filter 10. Other configurations are the same as those of the first embodiment described above.

  In the second embodiment configured as described above, since the return pipe 9 is connected to the supply pipe 8 located downstream of the swivel joint 7, the port of the swivel joint 7 is the same as in the first embodiment described above. The number can be reduced, and thereby the structure of the swivel joint 7 can be simplified, and the manufacturing cost can be reduced. Further, since it is not affected by the high-temperature unburned fuel returned from the engine 4 or the relatively high-temperature hydraulic fluid flowing through the swivel joint 7, the temperature rise of the fuel supplied to the engine 4 can be suppressed. As a result, the combustion efficiency of the engine 4 can be improved. Furthermore, the temperature of the unburned fuel returned from the engine 4 can be lowered by the heat exchanger 12, whereby the temperature of the combined fuel supplied to the engine 4 can be lowered, and the combustion efficiency of the engine 4 is increased. be able to.

  In the second embodiment, since the heat exchanger 12 is provided in the supply pipe 8, the temperature of the fuel discharged from the feed pump 5 can also be lowered by the heat exchanger 12. Therefore, the temperature of the joined fuel supplied to the engine 4 can be more reliably lowered, which contributes to increasing the combustion efficiency of the engine 4.

  FIG. 4 is a circuit diagram showing a third embodiment of the fuel circuit according to the present invention. In the third embodiment shown in FIG. 4, one end is connected to the return line 9, and the other end is connected to the supply line 8 located downstream of the heat exchanger 12 and upstream of the filter 10. A branch pipe 14 is provided, and a relief valve 15 that opens and closes according to the viscous resistance of unburned fuel guided to the return pipe 9 is arranged in the branch pipe 14. Other configurations are the same as those of the second embodiment described above.

  The third embodiment configured as described above is not used when the temperature of unburned fuel returned from the engine 4 to the return line 9 is relatively low, such as when the engine 4 is started in a low-temperature working environment. When the viscous resistance of the fuel increases, the relief valve 15 is opened, and the unburned fuel returned to the return line 9 is guided from the branch line 14 to the supply line 8 via the relief valve 15. That is, the unburned fuel returned to the return line 9 is guided to the supply line 8 without passing through the heat exchanger 12 and merges with the fuel discharged from the feed pump 5. Further, when the temperature of the unburned fuel returned from the engine 4 to the return line 9 is increased, the viscous resistance of the unburned fuel is reduced, so that the relief valve 15 is held closed, and the unburned fuel is Without being led to the branch pipe 14, it is led to the supply pipe 8 portion located upstream of the heat exchanger 12 and merges with the fuel discharged from the feed pump 5, and the merged fuel is passed through the heat exchanger 12. To be cooled. Therefore, in addition to the same effects as the second embodiment described above, unburned fuel guided to the return line 9 having a relatively low temperature is passed through the heat exchanger 12 during start-up in a low-temperature working environment. Thus, the engine 4 can be started smoothly.

It is a side view which shows the wheel shovel mentioned as an example of the all-swivel work vehicle with which each embodiment of the fuel circuit which concerns on this invention is provided. 1 is a circuit diagram showing a first embodiment of a fuel circuit according to the present invention. It is a circuit diagram which shows 2nd Embodiment of the fuel circuit which concerns on this invention. It is a circuit diagram which shows 3rd Embodiment of the fuel circuit which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Traveling body 2 Revolving body 2b Engine room 3 Front work machine 4 Engine 5 Feed pump 6 Fuel tank 7 Swivel joint 8 Supply line 9 Return line 10 Filter 11 Check valve 12 Heat exchanger 13 Motor 14 Branch line 15 Relief valve

Claims (5)

Provided in an all-turn work vehicle having a traveling body, a revolving body disposed on the traveling body, and a swivel joint interposed between the traveling body and the revolving body,
An engine disposed in the revolving body, a feed pump disposed in the traveling body and discharging fuel supplied to the engine, a fuel tank disposed in the traveling body and storing fuel sucked into the feed pump; A supply line connected to the feed pump and extending through the swivel joint to the swivel body for supplying fuel to the engine, and a return line for returning unburned fuel not burned by the engine. In the fuel circuit of a fully swivel work vehicle,
A fuel circuit for a full-swivel work vehicle, wherein the return line is connected to the supply line portion located downstream of the swivel joint. In the fuel circuit of the all-swivel work vehicle according to claim 1,
A fuel circuit for an all-swivel work vehicle, comprising a heat exchanger for cooling unburned fuel returned from the return pipe and having a high temperature. In the fuel circuit of the all-swivel work vehicle according to claim 2,
A fuel circuit for an all-swivel work vehicle, wherein the heat exchanger is disposed in the return pipe. In the fuel circuit of the all-swivel work vehicle according to claim 2,
A fuel circuit for an all-swivel work vehicle, characterized in that the heat exchanger is disposed in the supply line portion located downstream of a connection point between the supply line and the return line. In the fuel circuit of the all-swivel work vehicle according to claim 4,
One branch is connected to the return pipe, and the other end is connected to the supply pipe portion located downstream of the heat exchanger. The branch pipe is led to the return pipe in the branch pipe. A fuel circuit for a full-swivel work vehicle, wherein a relief valve that opens and closes according to the viscous resistance of unburned fuel is disposed.

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