JP2008126843A - Cooling device for working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling device for a working machine capable of blowing off dust or the like deposited on a heat exchanger to enhance the cleaning work efficiency by effectively increasing the flow rate of a cleaning air flow. <P>SOLUTION: When cleaning first and second heat exchangers 14, 15, any one of first and second directional control valves 21, 25 is changed to the changing position (c) to reversely control a cooling fan 16 or a cooling fan 18, and the other directional control valve is changed to the stop position (a) to stop the rotation of the cooling fan. For example, when the directional control valve 25 is changed to the stop position (a), diversion of a pressurized oil from a hydraulic pump 12 to a hydraulic motor 19 side can be blocked. On the side of one directional control valve 21 changed to the changing position (c), the pressurized oil from the hydraulic pump 12 is fully fed to a corresponding hydraulic motor 17, and the cooling fan 16 is reversely rotated at a high speed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is mounted on, for example, a hydraulic excavator, a hydraulic crane, a wheel loader, a cargo handling machine, and the like, and is used for cooling a heat exchanger such as a radiator and an oil cooler that is preferably used for cooling by a cooling air from a cooling fan. Relates to the device.

  In general, a work machine such as a hydraulic excavator is equipped with a plurality of heat exchangers for cooling the prime mover and the hydraulic equipment by heat exchange, and these heat exchangers have cooling fans for generating cooling air. It is attached. A configuration in which these cooling fans are rotationally driven by a hydraulic motor is known (see, for example, Patent Documents 1, 2, and 3).

  In this type of prior art, for example, a building cover that defines a machine room is provided on a frame of a vehicle body, and a hydraulic power source is configured with a prime mover composed of a diesel engine and the like and a tank that is rotated by the prime mover. A second heat exchange comprising a first heat exchanger comprising a hydraulic pump for cooling, a radiator for cooling the cooling water of the prime mover, and an oil cooler for cooling hydraulic oil supplied and discharged from the hydraulic source to the hydraulic actuator. And first and second cooling fans for supplying cooling air to these heat exchangers.

  When these cooling fans are driven to rotate by a prime mover or a hydraulic motor, the outside air is sucked into the machine room in the building cover as cooling air, and the cooling air blows the prime mover, the hydraulic pump, each heat exchanger, etc. It can be cooled (air cooled by an air flow).

  In this type of prior art, the rotation direction of the cooling fan can be appropriately changed by using a hydraulic motor as a driving source of the cooling fan, and for example, a cleaning operation for the heat exchanger can be easily performed. There is an advantage.

  That is, the airflow (cooling air) sucked into the machine room by one-way rotation (forward rotation) of the cooling fan contains a large amount of dust such as dust and dust that is likely to be generated at the work site. And if these dusts adhere to the dust-proof net of a heat exchanger, the surface of an apparatus, etc., the heat exchange effect by cooling air will fall.

  For this reason, by rotating the cooling fan in the other direction (reverse rotation) with the hydraulic motor, for example, an air flow from the machine room to the outside can be periodically generated as a cleaning air flow, and the heat exchanger It is possible to remove dust and the like adhering to the outside by blowing off with a cleaning air flow.

JP 2000-274242 A JP 2002-192959 A JP 2006-63882 A

  By the way, in the above-described prior art, in many cases, one of the first and second cooling fans is driven to rotate by a prime mover and the other cooling fan is driven to rotate by a hydraulic motor.

  For this reason, for example, when performing the cleaning operation on the first and second heat exchangers, the cleaning operation can be performed on the cooling fan side using the hydraulic motor by performing a reverse rotation operation. On the side of the cooling fan that is rotated at, the cooling fan cannot be rotated in the reverse direction by the prime mover, and there is a problem that it is difficult to clean the heat exchanger.

  Therefore, the present inventors have examined rotating the first and second cooling fans using hydraulic motors. However, in this case, for example, when the cleaning operation is performed on the first and second heat exchangers, the first and second cooling fans are simply rotated in reverse by the respective hydraulic motors.

  Therefore, the cleaning air flow that can be generated by reversely rotating the first and second cooling fans by the respective hydraulic motors cannot be increased to a flow rate sufficient to blow off dust and the like. There is an unsolved problem that the flow rate of the flow becomes insufficient.

  That is, the flow rate of the pressure oil supplied and discharged from the single hydraulic source to the two hydraulic motors is divided into, for example, 1/2 the flow rate and supplied to each hydraulic motor in order to reversely rotate each hydraulic motor together. Is done. As a result, the number of rotations of each cooling fan (the number of rotations during reverse operation) is limited to a number of rotations proportional to the flow rate of each hydraulic motor.

  As a result, the flow rate (air volume) of the cleaning air flow due to the reverse rotation of the cooling fan is insufficient, and dust etc. remain attached to the heat exchanger, and the original heat exchange action is hindered by adhering or clogged dust etc. However, there is a problem that it tends to cause so-called overheating.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to effectively increase the flow rate of the cleaning air flow and to blow away dust and the like adhering to the heat exchanger, thereby improving the cleaning workability. An object of the present invention is to provide a work machine cooling apparatus that can improve the operating efficiency of a heat exchanger and a cooling fan.

  In order to solve the above-described problems, a work machine cooling device according to a first aspect of the present invention includes a first heat exchanger that cools cooling water of a prime mover of a work machine, and a second heat oil that cools hydraulic fluid of a hydraulic device. A heat exchanger, first and second cooling fans that blow cooling air to the first and second heat exchangers, and pressure oil is supplied and discharged from a hydraulic pressure source, thereby the first and first cooling fans. First and second hydraulic motors for rotating the two cooling fans, and the first and second hydraulic motors provided in parallel with each other between the first and second hydraulic motors and the hydraulic source. First and second directional control valves for switching the supply and discharge directions of the pressure oil to and from the motor, and the first and second directional control valves are configured to stop the first and second cooling fans. A stop position for stopping the supply and discharge of the pressure oil, and supplying and discharging the pressure oil in one direction in order to rotate the first and second cooling fans forward The first switching position and the second switching position for supplying and discharging the pressure oil in the other direction in order to reverse the first and second cooling fans. When cleaning the second heat exchanger, one of the first and second directional control valves is switched to the second switching position to reversely control the cooling fan, and the other direction The control valve is configured to stop the rotation of the cooling fan by switching to the stop position.

  The invention of claim 2 is provided with operation means for cleaning the heat exchanger, and when the operation means is set to the cleaning mode, the one direction control valve is controlled to be switched to the second switching position. The other direction control valve is controlled to be switched to the stop position.

  According to a third aspect of the present invention, the hydraulic source is configured using a variable displacement hydraulic pump that is rotationally driven by the prime mover, and when the operating means is in a cleaning mode, the discharge capacity of the hydraulic pump is set. Is switched from the small capacity side to the large capacity side.

  As described above, according to the first aspect of the invention, when the first and second heat exchangers are cleaned, one of the first and second directional control valves is changed to the first directional control valve. Since the cooling fan is reversely controlled by switching to the switching position 2 and the other direction control valve is configured to stop the rotation of the cooling fan by switching to the stop position, one direction switched to the second switching position. On the control valve side, all the pressure oil can be supplied without diverting the pressure oil from the hydraulic source to the corresponding hydraulic motor, and the rotation speed of the hydraulic motor is proportional to the flow rate of the pressure oil. In addition to being able to increase, the number of rotations of the cooling fan to be reversely controlled can be increased efficiently, and the flow rate of the cleaning airflow can be increased.

  Therefore, when the first and second heat exchangers are cleaned, one cooling fan is reversely controlled and the other cooling fan is temporarily stopped to effectively increase the flow rate of the cleaning air flow. The dust and the like attached to the heat exchanger can be blown away to improve the cleaning workability. Thereby, the operating efficiency of a heat exchanger or a cooling fan can be improved, and the original heat exchange action can be maintained over a long period of time.

  According to the second aspect of the present invention, when the operation means is set to the cleaning mode, the one direction control valve and the other direction control valve are controlled to be switched between the second switching position and the stop position. Therefore, according to the selection operation of the cleaning mode by the operation means, the first and second cooling fans can be selectively reversely controlled, and the heat exchanger cleaning operation is performed at a large flow rate over a necessary time. Can do.

  Further, in the invention described in claim 3, when the hydraulic source is configured by using a variable displacement hydraulic pump that is rotationally driven by the prime mover, and the operation means is in the cleaning mode, the discharge capacity of the hydraulic pump is reduced to a small capacity. Since it is configured to switch from the side to the large capacity side, it is possible to prevent the flow rate of the pressure oil supplied to and discharged from the hydraulic source to the first and second hydraulic motors from being suddenly changed. Thus, forward, reverse, and stop control of the hydraulic motor can be performed smoothly.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a work machine cooling apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings, taking as an example a case of applying to a hydraulic excavator.

  Here, FIG. 1 to FIG. 6 show a first embodiment of the present invention. In the figure, reference numeral 1 denotes a hydraulic excavator as a work machine. The hydraulic excavator 1 includes a self-propelled crawler-type lower traveling body 2 and an upper revolving body 3 that is turnably mounted on the lower traveling body 2. The vehicle body is constituted by the above, and a work device 4 for excavation work is provided on the front side of the upper swing body 3.

  The cooling device for the hydraulic excavator 1 includes first and second heat exchangers 14 and 15 to be described later, first and second cooling fans 16 and 18, first and second hydraulic motors 17 and 19, The first and second directional control valves 21 and 25, the control unit 28, and the first and second switches 29 and 30 are configured.

  5 is a revolving frame as a vehicle body frame that forms the base of the upper revolving structure 3, and the working device 4 is attached to the front side of the revolving frame 5 so as to be able to move up and down, and on the rear end side of the revolving frame 5, A counterweight 6 that balances the weight with the work device 4 is attached.

  Further, a cab 7 that defines a cab is provided on the revolving frame 5 at a position on the left side of the front of the upper revolving structure 3. Inside the cab 7, a driver seat on which an operator is seated, an operation lever (None of them are shown) and switches 29 and 30 described later are provided.

  8 is a hydraulic oil tank provided on the revolving frame 5, and the hydraulic oil tank 8 is arranged at the left side position behind the cab 7 as shown in FIG. 2, for traveling, turning, working, etc. The hydraulic oil to be supplied to various hydraulic actuators is stored. A fuel tank 9 is provided at a position on the right side of the revolving frame 5, and the fuel tank 9 stores fuel supplied to an engine 11 described later.

  A building cover 10 is located on the front side of the counterweight 6 and is provided on the revolving frame 5. The building cover 10 includes an engine 11, a hydraulic pump 12, and a heat exchanger 14, which will be described later, as shown in FIGS. 15, 15, cooling fans 16, 18, and the like are configured from the outside. Further, for example, dustproof nets 10A and 10B are detachably attached to the side surface portion of the building cover 10 on the right side surface portion.

  Here, the dustproof nets 10A and 10B constitute a vent for circulating cooling air in the building cover 10, and are arranged in parallel in the front and rear directions of the building cover 10 as shown in FIGS. Has been. The dust-proof nets 10A and 10B prevent dust such as dust generated at the work site from entering the building cover 10, and the dust-proof net 10A covers a heat exchanger 14 described later from the outside. ing. The dust-proof net 10B covers the heat exchanger 15 and the like described later from the outside.

  11 is an engine as a prime mover located on the front side of the counterweight 6 and provided on the rear side of the swivel frame 5. The engine 11 is arranged on the left side on the rear side of the swivel frame 5 as shown in FIGS. It is arranged horizontally so as to extend in the right direction. A hydraulic pump 12 and a pilot pump 13 are provided on the left side of the engine 11, and these hydraulic pump 12 and pilot pump 13 are rotationally driven by the engine 11.

  Here, the hydraulic pump 12 is composed of a variable displacement hydraulic pump having a displacement variable portion 12A as shown in FIG. 5 and constitutes a main hydraulic source together with the hydraulic oil tank 8. The hydraulic pump 12 sucks the hydraulic oil in the hydraulic oil tank 8 and discharges the high-pressure oil, and the discharge amount at this time is variably controlled according to the tilt angle of the capacity variable portion 12A. Is. The pilot pump 13 constitutes an auxiliary hydraulic pressure source together with the hydraulic oil tank 8, sucks the hydraulic oil in the hydraulic oil tank 8, and discharges a pilot pressure described later as relatively low pressure oil.

  Reference numeral 14 denotes a first heat exchanger disposed at a position on the right side of the engine 11, and the first heat exchanger 14 includes a radiator 14A, an intercooler 14B, and the like as shown in FIGS. The radiator 14A cools the cooling water of the engine 11 by a heat exchange action as will be described later. The intercooler 14B cools the heat of air (supercharged air) sucked by a turbocharger (not shown) by heat exchange with cooling air.

  Reference numeral 15 denotes a second heat exchanger disposed in the building cover 10 on the front side of the first heat exchanger 14, and the second heat exchanger 15 includes an oil cooler 15A, an air conditioner condenser. 15B, a fuel cooler 15C, and the like. The oil cooler 15A cools the heat of the hydraulic oil (returned oil) returning from the hydraulic equipment such as various hydraulic actuators mounted on the hydraulic excavator 1 toward the hydraulic oil tank 8 by heat exchange with the cooling air. The oil temperature in the hydraulic oil tank 8 is kept at a relatively low temperature.

  The air conditioner condenser 15B cools the refrigerant of an air conditioner (not shown) that harmonizes the air in the cab 7. On the other hand, the fuel cooler 15C cools the fuel stored in the fuel tank 9 for the purpose of reducing harmful components in the exhaust gas, for example.

  Reference numeral 16 denotes a first cooling fan provided in the building cover 10 so as to face the first heat exchanger 14, and the first cooling fan 16 is driven to rotate by a first hydraulic motor 17. Then, outside air is sucked into the building cover 10 from the dust-proof net 10A side, and the outside heat is used as cooling air in the direction of arrow A shown in FIG. 4 to form the first heat exchanger 14 (radiator 14A, intercooler 14B), engine 11, etc. Distributed (supplied).

  In addition, when dust such as sand and dust generated at the work site adheres to the surroundings of the vent hole of the dust-proof net 10A and the dust-proof net 10A is clogged, the first cooling fan 16 will be described later. In this case, the cleaning airflow is generated in the direction opposite to the direction indicated by the arrow A in FIG. 4 (the direction indicated by the arrow A1).

  Reference numeral 18 denotes a second cooling fan provided in the building cover 10 so as to face the second heat exchanger 15. The second cooling fan 18 is driven to rotate by a second hydraulic motor 19. Then, outside air is sucked into the building cover 10 from the dust-proof net 10B side, and this outside air is circulated in the direction of arrow B in FIG. 4 as cooling air. The second heat exchanger 15 (oil cooler 15A, condenser 15B, fuel cooler 15C) is cooled by heat exchange with cooling air in the direction indicated by arrow B by the cooling fan 18.

  Further, the second cooling fan 18 is also reversely rotated (reversed) as necessary, as will be described later, and generates a cleaning air flow in the direction opposite to the direction indicated by the arrow B in FIG. 4 (the direction indicated by the arrow B1). The dust or the like attached to the dust-proof net 10B is blown off by the cleaning air flow to prevent the dust-proof net 10B from being clogged.

  Reference numerals 20A and 20B denote first main lines for supplying and discharging pressure oil to and from the first hydraulic motor 17, and the main lines 20A and 20B include a variable displacement hydraulic pump 12 and a hydraulic oil tank 8 as shown in FIG. Are connected to the first hydraulic motor 17, and pressure oil from the hydraulic pump 12 is supplied to and discharged from the first hydraulic motor 17.

  Reference numeral 21 denotes a first directional control valve provided in the middle of the main pipelines 20A and 20B. The first directional control valve 21 is composed of, for example, a directional control valve at a 4-port 3-position, Are provided with hydraulic pilot portions 21A, 21B. The hydraulic pilot portions 21A and 21B of the direction control valve 21 are selectively connected to the pilot pump 13 and the hydraulic oil tank 8 via the pilot pipelines 22A and 22B.

  Here, the directional control valve 21 switches to either the stop position (a), the first switching position (b), or the second switching position (c) according to the pilot pressure supplied to the hydraulic pilot portions 21A and 21B. In the stop position (a), the supply and discharge of the pressure oil is stopped and the rotation of the hydraulic motor 17 is stopped.

  When the directional control valve 21 is switched from the stop position (a) to the first switching position (b), the hydraulic oil is supplied and discharged in one direction from the hydraulic pump 12 toward the hydraulic motor 17. Is rotated in the forward direction (forward rotation). On the other hand, when the direction control valve 21 is switched from the first switching position (b) to the second switching position (c), the pressure oil is supplied and discharged from the hydraulic pump 12 toward the hydraulic motor 17 in the other direction, As a result, the hydraulic motor 17 is rotated (reversely rotated) in the reverse direction.

  23A and 23B are electromagnetic valves as switching valves provided in the middle of the pilot pipelines 22A and 22B. The electromagnetic valves 23A and 23B are excited or demagnetized according to a control signal from a control unit 28 described later. Then, the solenoid valves 23A and 23B are demagnetized at all times as shown in FIG. 5, thereby reducing the pilot pressure to be supplied to the hydraulic pilot portions 21A and 21B to the tank pressure. At the switching position (b).

  Further, in the state where one of the electromagnetic valves 23A and 23B is excited and the other electromagnetic valve 23B is demagnetized, the pilot pressure rises on the one hydraulic pilot portion 21A side, whereby the direction control valve 21 Is switched from the first switching position (b) to the second switching position (c). When one solenoid valve 23A is demagnetized and the other solenoid valve 23B is excited, the pilot pressure rises on the other hydraulic pilot portion 21B side, so that the direction control valve 21 is in the first switching position ( It is possible to switch from b) to the stop position (a).

  Reference numerals 24A and 24B denote second main pipes for supplying and discharging pressure oil to and from the second hydraulic motor 19, and the second main pipes 24A and 24B operate with the variable displacement hydraulic pump 12 as shown in FIG. The oil tank 8 is connected in parallel with the first main pipelines 20A and 20B. The main pipelines 24A and 24B connect the variable displacement hydraulic pump 12 and the hydraulic oil tank 8 to the second hydraulic motor 19, and supply and discharge pressure oil from the hydraulic pump 12 to the second hydraulic motor 19. To do.

  Reference numeral 25 denotes a second directional control valve provided in the middle of the main pipelines 24A and 24B. The second directional control valve 25 is constituted by, for example, a directional control valve at a 4-port 3-position, Are provided with hydraulic pilot portions 25A and 25B. The hydraulic pilot portions 25A and 25B of the directional control valve 25 are selectively connected to the pilot pump 13 and the hydraulic oil tank 8 via pilot pipelines 26A and 26B.

  Here, the second directional control valve 25 is arranged in parallel via the directional control valve 21 on the main pipelines 20A, 20B side and the main pipelines 24A, 24B. The direction control valve 25 is controlled to switch to either the stop position (a), the first switching position (b), or the second switching position (c) according to the pilot pressure supplied to the hydraulic pilot units 25A and 25B. At the stop position (a), the supply and discharge of the pressure oil is stopped and the rotation of the hydraulic motor 19 is stopped.

  When the direction control valve 25 is switched from the stop position (a) to the first switching position (b), the pressure oil is supplied and discharged from the hydraulic pump 12 toward the hydraulic motor 19 in one direction. Is rotated in the forward direction (forward rotation). On the other hand, when the direction control valve 25 is switched from the first switching position (b) to the second switching position (c), the pressure oil is supplied and discharged from the hydraulic pump 12 toward the hydraulic motor 19 in the other direction, As a result, the hydraulic motor 19 is rotated (reversely rotated) in the reverse direction.

  27A and 27B are electromagnetic valves as switching valves provided in the middle of the pilot pipelines 26A and 26B. The electromagnetic valves 27A and 27B are excited or demagnetized according to a control signal from the control unit 28 described later. The electromagnetic valves 27A and 27B are demagnetized at all times as shown in FIG. 5, thereby reducing the pilot pressure to be supplied to the hydraulic pilot portions 25A and 25B to the tank pressure. At the switching position (b).

  Further, when one of the electromagnetic valves 27A and 27B is excited and the other electromagnetic valve 27B is demagnetized, the pilot pressure increases on the one hydraulic pilot portion 25A side, whereby the direction control valve 25 Is switched from the first switching position (b) to the second switching position (c). When one solenoid valve 27A is demagnetized and the other solenoid valve 27B is excited, the pilot pressure rises on the other hydraulic pilot portion 25B side, so that the direction control valve 25 is in the first switching position ( It is possible to switch from b) to the stop position (a).

  Reference numeral 28 denotes a control unit constituted by a microcomputer or the like. The control unit 28 has an input side connected to switches 29 and 30 as operation means, and an output side connected to electromagnetic valves 23A and 23B, electromagnetic valves 27A and 27B, and the like. It is connected. The control unit 28 has a storage unit 28A composed of a ROM, a RAM, and the like. The storage unit 28A stores a rotation control program for the cooling fans 16 and 18 shown in FIG.

  Here, the first switch 29 switches the first directional control valve 21 and is selected by, for example, an operator's manual operation at three positions of “forward operation”, “reverse operation”, or “stop operation”. Can be switched. When the first switch 29 is set to “forward operation”, both the electromagnetic valves 23A and 23B remain demagnetized by a signal from the control unit 28, and the first directional control valve 21 is shown in FIG. 1 is placed at the switching position (b).

  When the first switch 29 is set to “reverse operation”, the electromagnetic valve 23A is excited by a signal from the control unit 28, and the electromagnetic valve 23B is held in a demagnetized state, whereby the first directional control valve 21 is operated. Is switched from the first switching position (b) shown in FIG. 5 to the second switching position (c). On the other hand, when the first switch 29 is set to “stop operation”, the electromagnetic valve 23A is demagnetized by the signal from the control unit 28, and the electromagnetic valve 23B is excited, so that the first directional control valve 21 is in FIG. The first switching position (b) shown in FIG. 2 is switched to the stop position (a).

  The second switch 30 switches the second directional control valve 25, and is selectively switched at three positions of "forward rotation operation", "reverse rotation operation" or "stop operation" by the operator's manual operation. It is done. Then, the second directional control valve 25 is operated in the same manner as the first directional control valve 21 in accordance with the operation of the switch 30. The first switching position (b), the second switching position (c), or the stop position (a). Is switched to.

  5 indicates a relief valve. The relief valve 31 sets, for example, the highest pressure in the main pipelines 20A and 20B and the main pipelines 24A and 24B. 19, prevents the directional control valves 21 and 25 from acting.

  The cooling device for the hydraulic excavator 1 according to the present embodiment has the above-described configuration. Next, rotation control processing of the cooling fans 16 and 18 by the control unit 28 will be described with reference to FIG.

  First, when the processing operation starts with the start of the engine 11 or the like, the operation of both the switches 29 and 30 is read in Step 1, and in Step 2, whether or not both the switches 29 and 30 are “normally operated”. Determine whether. When it is determined as “YES” in step 2, the process proceeds to step 3 to perform control for reducing the flow rate of the pressure oil to the minimum flow rate.

  That is, in the control of Step 3, the displacement variable portion 12A of the hydraulic pump 12 shown in FIG. This reduces the flow rate of the pressure oil supplied to and discharged from the hydraulic motors 17 and 19 to the minimum flow rate, and suppresses the occurrence of surge pressure or the like when the direction control valves 21 and 25 are switched.

  In the next step 4, since both the switches 29 and 30 are “normally operated”, the directional control valves 21 and 25 are both switched to the first switching position (b) accordingly. As a result, the hydraulic oil from the hydraulic pump 12 is supplied to and discharged from the hydraulic motors 17 and 19 in one direction (forward direction), and both the first and second cooling fans 16 and 18 are rotated forward.

  Next, in step 5, with the directional control valves 21 and 25 both switched to the first switching position (b), the routine proceeds to a conventionally known cooling process (control process for cooling). The flow rate of the pressure oil supplied to and discharged from the hydraulic motors 17 and 19 is increased as usual. That is, in this case, the capacity variable portion 12A of the hydraulic pump 12 is driven to tilt toward the large capacity side, and the rotation speed of the engine 11 is increased to the normal engine rotation speed, thereby supplying the hydraulic motors 17 and 19 with the rotation. The flow rate of the discharged pressure oil is increased to the required flow rate.

  As a result, in the building cover 10 of the upper swing body 3 shown in FIG. 4, cooling air is generated in the direction indicated by the arrow A from the dustproof net 10 </ b> A along with the forward rotation of the first cooling fan 16. The first heat exchanger 14 (radiator 14A, intercooler 14B) can be cooled by heat exchange with the cooling air, and the engine 11 and the like can also be cooled from the outside.

  At this time, since the second cooling fan 18 also rotates in the forward direction (forward rotation), cooling air can be generated in the building cover 10 from the dust-proof net 10B side in the direction indicated by the arrow B. Thus, the second heat exchanger 15 (oil cooler 15A, condenser 15B, fuel cooler 15C) can be cooled by heat exchange, and the engine 11 and the like can be cooled from the outside. Then, in step 6, the process returns to the main control process (not shown).

  Next, when it is determined as “NO” in Step 2, since both the switches 29 and 30 are not “forwardly operated”, the process proceeds to the next Step 7 and one of the switches 29 and 30 is turned on. It is determined whether or not “reverse operation” has been performed. If “YES” is determined in the step 7, the process proceeds to the next step 8 to determine whether or not the other switch is “stopped”.

  When it is determined as “YES” in step 8, one of the switches 29 and 30 is “reverse operation” and the other is “stop operation”. It can be determined that the cleaning mode is set.

  Therefore, in this case, for example, only the hydraulic motor 17 (or the hydraulic motor 19) shown in FIG. 5 is reversely rotated and the hydraulic motor 19 (or the hydraulic motor 17) is stopped, so that the pressure oil from the hydraulic pump 12 is discharged. It is possible to concentrate and supply all the hydraulic oil to one hydraulic motor without diverting it to the hydraulic motors 17 and 19, to reliably increase the reverse rotation speed (rotation speed), and to perform so-called cleaning work efficiently. Can do.

  That is, when “YES” is determined in Step 8, the process proceeds to Step 9 to perform control for reducing the flow rate of the pressure oil to the minimum flow rate as in the process of Step 3 described above. In the next step 10, one directional control valve (for example, the directional control valve 21) is switched to the second switching position (c), and the hydraulic motor 17 is slowly reversed. In step 11, the other directional control valve (for example, directional control valve 25) is switched to the stop position (a) to stop the hydraulic motor 19.

  Next, in step 12 in this state, control for increasing the flow rate of the pressure oil is performed for a predetermined time (for example, about 10 to 60 seconds). In this case, the displacement variable portion 12A of the hydraulic pump 12 is tilted to the large displacement side, and the rotational speed of the engine 11 is increased to a high idle rotational speed (for example, about 1900 rpm).

  As a result, the flow rate of the pressure oil supplied to and discharged from the hydraulic motor 17 that has started reverse rotation is increased, and the reverse rotation speed of the cooling fan 16 is increased to the rotational speed necessary for the cleaning operation described later. When the predetermined time has elapsed, the process proceeds to step 6 and returns.

  On the other hand, when “NO” is determined in Step 7, for example, since both the switches 29 and 30 are “reversely operated”, the process from Step 3 to Step 5 is also performed in this case. In this case, the directional control valves 21 and 25 are respectively switched to the second switching position (c) in accordance with the “reverse operation” of the switches 29 and 30.

  As a result, the hydraulic oil from the hydraulic pump 12 is supplied to and discharged from the hydraulic motors 17 and 19 in the other direction (reverse direction), and the first and second cooling fans 16 and 18 are rotated in reverse. At this time, the first cooling fan 16 generates cooling air in the direction opposite to the direction indicated by the arrow A in FIG. 4 (the direction indicated by the arrow A1). The cooling air is generated in the direction opposite to the direction indicated by B (the direction indicated by arrow B1).

  If “NO” is determined in Step 8, for example, the two switches 29 and 30 are both “stopped”, and in this case as well, the processing from Step 3 to Step 5 is executed. In this case, the directional control valves 21 and 25 are switched to the stop position (a) in accordance with the “stop operation” of the switches 29 and 30 to stop the rotation of the hydraulic motors 17 and 19 and the cooling fans 16 and 18 are switched. Control to stop the rotation.

  Thus, according to the present embodiment, when the first and second heat exchangers 14 and 15 are cleaned, either one of the first and second directional control valves 21 and 25 ( For example, the direction control valve 21) is switched to the second switching position (c) to reversely control the cooling fan 16, and the other direction control valve (for example, the direction control valve 25) is switched to the stop position (a) for cooling. The rotation of the fan 18 is stopped.

  Thereby, the direction control valve 25 switched to the stop position (a) can block the pressure oil from the hydraulic pump 12 from being diverted to the hydraulic motor 19 side, and one direction control switched to the switch position (c). On the valve 21 side, all the hydraulic oil from the hydraulic pump 12 can be supplied to the corresponding hydraulic motor 17.

  As a result, the rotational speed of the hydraulic motor 17 that rotates in the reverse direction can be effectively increased in proportion to the flow rate of the pressure oil, and the rotational speed of the cooling fan 16 that is reversely controlled in accordance with the cleaning operation can be efficiently increased. The flow rate of the cleaning air flow in the direction of arrow A1 in FIG. 4 can be increased. For example, dust or the like adhering to the dustproof net 10A can be removed by the cleaning air flow in the direction of arrow A1. Can be removed by blowing away.

  When the direction control valve 25 is switched to the switching position (c) to control the cooling fan 18 in the reverse direction and the direction control valve 21 is switched to the stop position (a) to stop the rotation of the cooling fan 16, the direction is reversed. The rotational speed of the hydraulic motor 19 that rotates in an effective manner can be effectively increased in proportion to the flow rate of the pressure oil, and the number of rotations of the cooling fan 18 that is reversely controlled in accordance with the cleaning operation can be increased efficiently. 4 can increase the flow rate of the cleaning air flow in the direction of arrow B1 in FIG. 4, for example, dust and the like adhering to the dustproof net 10B is blown away by the cleaning air flow in the direction of arrow B1 and removed. be able to.

  Therefore, according to the present embodiment, when the first and second heat exchangers 14 and 15 are cleaned, one of the two cooling fans 16 and 18 is reversely controlled, and the other cooling fan is By temporarily stopping, the flow rate of the cleaning air flow can be effectively increased, and the dust adhering to the outer surfaces of the dust-proof nets 10A and 10B and the heat exchangers 14 and 15 is blown away to facilitate the cleaning work. It can be carried out.

  Thereby, the cleaning time of the heat exchangers 14 and 15 can be shortened, and the cleaning workability can be improved. Further, by maintaining the heat exchangers 14 and 15 in a clean cleaning state, the operation efficiency of the heat exchangers 14 and 15 and the cooling fans 16 and 18 can be increased, and the original heat exchange action can be maintained over a long period of time. be able to.

  Next, FIG. 7 and FIG. 8 show a second embodiment of the present invention. In this embodiment, the same reference numerals are given to the same components as those in the first embodiment described above, and the description thereof will be given. Shall be omitted.

  However, the feature of the present embodiment is that the cleaning mode setting operation is realized by using a single switch 41, and the cleaning operation for the first and second heat exchangers 14 and 15 is predetermined by the control unit 42. It is in the structure which performs continuously in the order.

  Here, the control unit 42 is configured in substantially the same manner as the control unit 28 described in the first embodiment, and a storage control program for the cooling fans 16 and 18 shown in FIG. Stored. And, on the output side of the control unit 42, solenoid valves 23A and 23B, solenoid valves 27A and 27B, and the like are connected. However, this embodiment is different from the first embodiment in that a single switch 41 is connected to the input side of the control unit 42 as an operation means.

  In other words, the switch 41 in this case is selectively switched between two positions of “normal operation” and “cleaning operation” by the manual operation of the operator. When the switch 41 is switched to the “cleaning operation”, the cleaning fan 16 and 18 are selectively reversely controlled as will be described later, and the cleaning operation for the first and second heat exchangers 14 and 15 is performed. Are executed in a predetermined order.

  Further, when the switch 41 is switched from the “cleaning operation” to the “normal operation”, the forward rotation control is performed so that both the cooling fans 16 and 18 rotate in the forward direction as will be described later, and the first and second heat exchangers are controlled. The operation of supplying cooling air to 14, 15 is performed as a normal cooling process.

  The cooling device for the hydraulic excavator 1 according to the present embodiment has the above-described configuration. Next, the rotation control processing of the cooling fans 16 and 18 by the control unit 42 will be described with reference to FIG.

  First, when the processing operation starts with the start of the engine 11 or the like, the operation of the switch 41 is read in step 21, and in step 22, it is determined whether or not the switch 41 is “cleaning operation”. When it is determined as “NO” in step 22, the switch 41 is switched to the “normal operation” side.

  In this case, therefore, the process goes to step 23 to control the cooling fans 16 and 18 to rotate forward. That is, the same control as in steps 3 and 4 in FIG. 6 described above is performed, and the directional control valves 21 and 25 are both switched to the first switching position (b), so that the pressure oil from the hydraulic pump 12 is reduced. Both the first and second cooling fans 16 and 18 are slowly rotated forward while supplying and discharging the hydraulic motors 17 and 19 in the direction (forward direction).

  Then, in the next step 24, the process proceeds to a conventionally known normal cooling process, and the flow rate of the pressure oil supplied to and discharged from the hydraulic motors 17 and 19 is increased as usual. As a result, the flow rate of the pressure oil supplied to and discharged from the hydraulic motors 17 and 19 is increased to a necessary flow rate, and the first heat exchanger 14 (radiator 14A, The intercooler 14B) and the second heat exchanger 15 (oil cooler 15A, condenser 15B, fuel cooler 15C) are cooled. Thereafter, in step 25, the process returns to the main control process (not shown).

  Next, when it is determined “YES” in step 22, the switch 41 is switched to “cleaning operation” and is set to the cleaning mode. Therefore, in this case, the process proceeds to the next step 26 to perform control for reducing the flow rate of the pressure oil to the minimum flow rate. That is, similarly to step 9 in FIG. 6, the displacement variable portion 12A of the hydraulic pump 12 is tilted and driven to a minimum capacity, and the rotational speed of the engine 11 is lowered to a so-called low idle rotational speed, thereby The flow rate of the pressure oil supplied to and discharged from the motors 17 and 19 is reduced to the minimum flow rate.

  Then, in the next step 27, for example, by switching one directional control valve 21 shown in FIG. 7 to the switching position (c), the hydraulic motor 17 is slowly reversely rotated to perform the reverse rotation control of the cooling fan 16. In step 28, the other direction control valve 25 is switched to the stop position (a) to stop the hydraulic motor 19 and to control the cooling fan 18 to stop.

  Next, in this state, in step 29, control for increasing the flow rate of the pressure oil is performed for a predetermined time (for example, about 10 to 60 seconds). That is, in this case, the displacement variable portion 12A of the hydraulic pump 12 is driven to tilt toward the large displacement side, and the rotational speed of the engine 11 is increased to a high idle rotational speed. As a result, the flow rate of the pressure oil supplied to and discharged from the hydraulic motor 17 that has started reverse rotation is increased, and the reverse rotation speed of the cooling fan 16 is increased to the rotational speed necessary for the cleaning operation.

  Then, when the predetermined time has elapsed, the process proceeds to the next step 30 to perform control for reducing the flow rate of the pressure oil to the minimum flow rate as in the process of step 26 described above. Next, at step 31, the directional control valve 25 is switched to the switching position (c), so that the hydraulic motor 19 is slowly reversely rotated and the cooling fan 18 is reversely controlled.

  In step 32, the hydraulic motor 17 is stopped by switching the direction control valve 21 to the stop position (a), and the cooling fan 16 is controlled to stop. Then, in the next step 33 in this state, the control for increasing the flow rate of the pressure oil is performed for a predetermined time as in the above-described step 29.

  As a result, the flow rate of the pressure oil supplied to and discharged from the hydraulic motor 19 that has started reverse rotation is increased, and the reverse rotation speed of the cooling fan 18 is increased to the rotational speed necessary for the cleaning operation. Then, when the predetermined time has elapsed, the cleaning operation for the heat exchangers 14 and 15 is completed or completed. Therefore, the process proceeds to the next step 34, and the flow rate of the pressure oil is changed in the same manner as the process of step 26 described above. Control to reduce to the minimum flow rate.

  Then, in the next step 35, both the direction control valves 21 and 25 are switched to the switching position (b) in order to return to the normal control in which the cooling fans 16 and 18 are both normally rotated. While supplying and discharging the pressure oil to and from the hydraulic motors 17 and 19, both the first and second cooling fans 16 and 18 are rotated forward. After that, the process returns to the above-described step 24, shifts to a conventionally known cooling process, and increases the flow rate of the pressure oil supplied to and discharged from the hydraulic motors 17 and 19 as usual. Thereafter, the process returns at step 25.

  Thus, even in the present embodiment configured as described above, it is possible to obtain substantially the same operational effects as those of the first embodiment described above, and by selectively rotating the cooling fans 16 and 18 in reverse, The cleaning work for the first and second heat exchangers 14 and 15 can be performed efficiently.

  In particular, in the present embodiment, the switch 41 is selectively switched between two positions of “normal operation” and “cleaning operation” by the manual operation of the operator. Therefore, when “normal operation” is selected, The heat exchangers 14 and 15 can be cooled by cooling air from the cooling fans 16 and 18.

  When the “cleaning operation” is selected by the switch 41, the processing from step 26 to step 33 in FIG. 8 can be continuously performed, and the reverse rotation control of the cooling fans 16 and 18 is selectively performed in a predetermined order. The cleaning work for the first and second heat exchangers 14 and 15 can be performed efficiently while performing the above.

  In the second embodiment, since the cleaning operation is performed on the first heat exchanger 14 side, the reverse rotation control of the cooling fan 16 is performed first, and then the cleaning operation is performed on the second heat exchanger 15 side. For this reason, the case where the reverse rotation control of the cooling fan 18 is performed has been described as an example. However, the present invention is not limited to this. For example, the reverse rotation control of the cooling fan 18 (cleaning operation on the heat exchanger 15 side) is performed first, and then the reverse rotation control of the cooling fan 16 (cleaning of the heat exchanger 14 side). It is good also as a structure which performs work.

  In each of the above-described embodiments, the hydraulic excavator 1 is described as an example of the work machine to be cooled. However, the present invention is not limited to this, and can be widely applied to various work machines including a plurality of heat exchangers such as a hydraulic crane, a wheel loader, a bulldozer, and a cargo handling machine.

  Moreover, in each said embodiment, the cooling device of the working machine provided with the 1st, 2nd heat exchangers 14 and 15 and the 1st, 2nd cooling fans 16 and 18 attached to this is provided. Explained with an example. However, the present invention is not limited to the case where two cooling fans are used. For example, the present invention is also applicable to a case where three or more cooling fans are driven and controlled using respective directional control valves connected in parallel by respective hydraulic motors. Applicable.

1 is a front view showing a hydraulic excavator to which a cooling device according to a first embodiment of the present invention is applied. It is the top view which looked at the excavator of FIG. 1 from upper direction. It is a front view of the hydraulic excavator which shows a heat exchanger etc. in the state which removed the dustproof net in FIG. It is a top view which removes a part of building cover and shows an internal engine, a hydraulic pump, a 1st, 2nd heat exchanger, etc. FIG. FIG. 3 is a hydraulic circuit diagram of a cooling device that drives and controls first and second cooling fans and the like. 6 is a flowchart showing rotation control processing and the like of each cooling fan by the control unit in FIG. It is a hydraulic-circuit figure of the cooling device by 2nd Embodiment. It is a flowchart which shows the rotation control processing of each cooling fan by the control unit in FIG.

Explanation of symbols

1 Excavator (work machine)
DESCRIPTION OF SYMBOLS 2 Lower traveling body 3 Upper revolving body 5 Turning frame 8 Hydraulic oil tank 9 Fuel tank 10 Building cover 10A, 10B Dust-proof net 11 Engine (motor)
12 Hydraulic pump (hydraulic equipment)
12A Capacity variable section 14 First heat exchanger 14A Radiator 14B Intercooler 15 Second heat exchanger 15A Oil cooler 15B Condenser 15C Fuel cooler 16 First cooling fan 17 First hydraulic motor 18 Second cooling fan 19 First 2 hydraulic motor 21 1st direction control valve 23A, 23B, 27A, 27B Solenoid valve (switching valve)
25 Second direction control valve 28, 42 Control unit 29, 30, 41 Switch (operation means)

Claims (3)

A first heat exchanger that cools the cooling water of the prime mover of the work machine, a second heat exchanger that cools hydraulic fluid of the hydraulic equipment, and cooling air to the first and second heat exchangers First and second cooling fans for blowing air, first and second hydraulic motors for rotating and driving the first and second cooling fans by supplying and discharging pressure oil from a hydraulic source, and the first , First and second directional control valves provided in parallel with each other between the second hydraulic motor and the hydraulic source for switching the pressure oil supply / discharge direction with respect to the first and second hydraulic motors. Prepared,
The first and second directional control valves rotate the first and second cooling fans in a forward direction and a stop position where supply and discharge of the pressure oil are stopped to stop the first and second cooling fans. Therefore, one of the first switching position for supplying and discharging the pressure oil in one direction and the second switching position for supplying and discharging the pressure oil in the other direction to reverse the first and second cooling fans. It is configured to be switched to
When cleaning the first and second heat exchangers, one of the first and second directional control valves is switched to the second switching position to reversely control the cooling fan. The other directional control valve switches to the stop position to stop the rotation of the cooling fan.   An operation means for cleaning the heat exchanger is provided, and when the operation means is set to the cleaning mode, the one direction control valve is controlled to be switched to the second switching position, and the other direction control valve is stopped. The work machine cooling device according to claim 1, wherein the work machine is controlled to be switched to a position.   The hydraulic power source is configured using a variable displacement hydraulic pump that is rotationally driven by the prime mover, and when the operation means is in a cleaning mode, the discharge capacity of the hydraulic pump is switched from a small capacity side to a large capacity side. The cooling device for a work machine according to claim 2, which is configured.

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