JP2012225460A - Cooling device of construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling device of a construction machine, which achieves reduction in energy loss incidental to driving of a cooling fan and can drives the cooling fan without using engine horsepower.SOLUTION: The cooling device includes a cooling fan 17 for blowing air to a heat exchanger, for example, an oil cooler 16 provided in a hydraulic shovel. The cooling device further includes: a branched oil passage 15b branched from a return oil passage 15a of a hydraulic actuator, for example, a boom cylinder 5; a pressure accumulation device 19 connected to the branched oil passage 15b; a hydraulic motor 18 disposed in a part of the branched oil passage 15b located downstream from the pressure accumulation device 19; and a valve 20, which is disposed in a part of the return oil passage 15a located between a tank 30 and a branch point 31 of the return oil passage 15a and the branch oil passage 15b and which opens and closes the return oil passage 15a in accordance with non-actuation or actuation of the boom cylinder 5, for example.

Description

  The present invention relates to a cooling device for a construction machine that is provided in a construction machine such as a hydraulic excavator and includes a cooling fan that cools a heat exchanger.

  There exists a thing shown by patent document 1 as this kind of prior art. This prior art is a cooling device provided in a construction machine or the like, and a hydraulic pump motor is provided in a return oil path from a hydraulic actuator in order to reduce engine horsepower consumed for driving a cooling fan that cools hydraulic oil. The cooling fan is driven by driving the hydraulic pump motor.

  That is, in this prior art, when the hydraulic actuator is operated, the hydraulic pump motor is driven by the return oil guided to the return oil passage from the hydraulic actuator, and thereby the pressure transducer mechanically connected to the hydraulic pump motor is provided. A variable displacement hydraulic pump to be formed is driven, a first hydraulic rotary machine (hydraulic motor) is driven by driving the variable displacement hydraulic pump, and a cooling fan is driven by the first hydraulic rotary machine. Further, when the hydraulic actuator is not operated, pressure oil from a hydraulic source driven by an engine or the like is supplied to the second hydraulic rotary machine (hydraulic motor), and the cooling fan is driven by the second hydraulic rotary machine. .

Japanese Patent No. 3897185

  The prior art described above requires a first hydraulic rotary machine and a second hydraulic rotary machine, that is, two hydraulic motors to drive the cooling fan, and pressure oil to the hydraulic motor that is the first hydraulic rotary machine is Since the return oil from the hydraulic actuator is supplied via the variable displacement hydraulic pump forming the pressure transducer, the configuration becomes very complicated, and the energy loss increases accordingly. Further, when the hydraulic actuator is not operated, the cooling fan is driven using the energy of the hydraulic source driven by the engine horsepower. For these reasons, there is a problem that it is difficult to expect improvement in the reduction efficiency of the engine horsepower in the conventional construction machine and the like.

  The present invention has been made from the above-described state of the art, and an object of the present invention is to reduce energy loss associated with driving of the cooling fan and to drive the cooling fan without using engine horsepower. An object of the present invention is to provide a cooling device for a construction machine.

  In order to achieve this object, the present invention provides an engine, a hydraulic pump driven by the engine, a hydraulic actuator operated by pressure oil discharged from the hydraulic pump, and a supply from the hydraulic pump to the hydraulic actuator. A directional control valve that controls the flow of the pressurized oil and an operating device that switches the directional control valve, and a cooling fan that is provided in a construction machine having a heat exchanger and blows air to the heat exchanger. The construction machine cooling apparatus includes a pressure accumulator provided in a return oil passage for guiding return oil from the hydraulic actuator, and a hydraulic motor provided downstream of the pressure accumulator and driving the cooling fan. The hydraulic motor is operated by the return oil when the hydraulic actuator is operated, and is operated when the hydraulic actuator is not operated. It is characterized by consisting of those capable of operation with the accumulator by pressure oil in the accumulator.

  In the present invention configured as described above, when the hydraulic actuator is operated, the return oil guided to the return oil passage of the hydraulic actuator is accumulated in the pressure accumulator, and the hydraulic motor is operated by the return oil, and is cooled by the hydraulic motor. The fan is driven to blow air to the heat exchanger, and the heat exchanger can be cooled. That is, the cooling motor can be driven by operating the hydraulic motor only by the return oil energy guided from the hydraulic motor through the return oil passage.

  Further, when the hydraulic actuator is not operated, the pressure oil stored in the pressure accumulating device is guided to the hydraulic motor, the hydraulic motor is operated, and the cooling fan can be driven.

  That is, according to the present invention, energy of the return oil guided to the return oil passage can be given to the hydraulic motor without requiring a pressure converter or the like, and the hydraulic motor can be driven. Therefore, generation of useless energy loss in the pressure transducer or the like can be suppressed, and energy loss accompanying driving of the cooling fan can be reduced. Further, the heat exchanger can be cooled by driving the cooling fan without using the engine horsepower regardless of whether the hydraulic actuator is activated or not.

  Further, the present invention is the above invention, wherein a branch oil passage branched from the return oil passage is provided, the pressure accumulator is connected to the branch oil passage, and the branch oil passage located downstream of the pressure accumulator is connected to the branch oil passage. The hydraulic motor is provided, and the return oil passage is disposed in a portion of the return oil passage located between a branch point between the return oil passage and the branch oil passage and the tank in accordance with the non-operation of the hydraulic actuator. An opening / closing means for opening and closing is provided.

  In the present invention configured as described above, when the hydraulic actuator is operated, the return oil path is closed by the opening / closing means, the return oil is guided from the return oil path to the branch oil path, and the return oil guided to the branch oil path Is stored in the pressure accumulator and the hydraulic motor is operated by the return oil. Further, when the hydraulic actuator is not operated, the return oil path is opened by the opening and closing means and the return oil path communicates with the tank, and the pressure oil stored in the pressure accumulator is guided to the hydraulic motor via the branch oil path, This hydraulic motor can be operated.

  Further, the present invention is the above invention, wherein the opening / closing means includes an on-off valve having a closed position for closing the return oil passage when the operation device is operated and an open position for opening the return oil passage when the operation device is neutral. It is characterized by that. In the present invention configured as described above, the on-off valve can be switched in association with the operation of the operating device that operates the hydraulic actuator.

  The present invention is characterized in that, in the above invention, the heat exchanger comprises an oil cooler provided in a portion of a return oil passage located between the on-off valve and the tank. In the present invention configured as above, the cooling fan can be driven by the operation of the hydraulic motor, and the air generated by the cooling fan can be applied to the oil cooler to cool the working oil.

  Further, the present invention is characterized in that, in the above invention, an end of the branch oil passage located downstream of the hydraulic motor is connected to a return oil passage located between the on-off valve and the oil cooler. It is said. According to the present invention configured as described above, the hydraulic oil whose temperature has increased in the hydraulic motor can be guided to the oil cooler, and the cooling function of the hydraulic oil can be enhanced.

  The present invention can drive the hydraulic motor by supplying energy of the return oil guided to the return oil path to the hydraulic motor without requiring a pressure converter or the like. Therefore, generation of useless energy loss in the pressure transducer or the like can be suppressed, and energy loss accompanying driving of the cooling fan can be reduced. Further, the heat exchanger can be cooled by driving the cooling fan without using the engine horsepower regardless of whether the hydraulic actuator is activated or not. That is, the present invention can reduce the energy loss associated with the driving of the cooling fan, and can drive the cooling fan without using the engine horsepower. It can be improved as compared.

It is a side view of a hydraulic excavator cited as an example of a construction machine provided with a cooling device according to the present invention. It is a hydraulic circuit diagram which shows the principal part structure of 1st Embodiment of the cooling device which concerns on this invention. It is a hydraulic circuit diagram which shows the principal part structure of 2nd Embodiment of this invention.

  Embodiments of a construction machine cooling apparatus according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a side view of a hydraulic excavator cited as an example of a construction machine provided with a cooling device according to the present invention.

  The hydraulic excavator shown in FIG. 1 includes a traveling body 1 and a revolving body 2 that is disposed on the traveling body 1 and that revolves by a revolving drive device 3. The hydraulic excavator includes a boom 4 attached to the swing body 2 so as to be rotatable in the vertical direction, a boom cylinder 5 for driving the boom 4, and an arm attached to the tip of the boom 4 so as to be rotatable in the vertical direction. 6, an arm cylinder 7 that drives the arm 6, a bucket 8 that is rotatably attached to the tip of the arm 6, and a bucket cylinder 9 that drives the bucket 8.

  The boom 4, the arm 6, the bucket 8, and the boom cylinder 5, the arm cylinder 7, and the bucket cylinder 9 constitute a working device for excavating soil and the like. Further, the boom cylinder 5, the arm cylinder 7, the bucket cylinder 9, a swing motor 3a (described later) included in the swing drive device 3, a travel motor (not shown) that travels the traveling body 1, and the like constitute a hydraulic actuator provided in the hydraulic excavator. Has been.

  FIG. 2 is a hydraulic circuit diagram showing the main configuration of the first embodiment of the cooling device according to the present invention.

  The hydraulic excavator provided with the first embodiment of the cooling device according to the present invention has an engine 10, a hydraulic pump 11 driven by the engine 10, and the hydraulic pump, as shown in FIG. 11 and hydraulic actuators such as the above-described boom cylinder 5 and the turning motor 3a, which are operated by pressure oil discharged from the motor 11. The hydraulic excavator also controls a boom direction control valve 13a for controlling the flow of pressure oil supplied from the hydraulic pump 11 to the boom cylinder 5, and controls the flow of pressure oil supplied from the hydraulic pump 11 to the swing motor 3a. A turning direction control valve 13b, a boom operation device 12a for switching the boom direction control valve 13a, and a turning operation device 12b for switching the turning direction control valve 13b are provided. Further, this hydraulic excavator is included in the return circuit 15, and a heat exchanger, for example, an oil cooler 16 is arranged in a return oil passage 15 a that returns the oil discharged from the boom cylinder 5 and the swing motor 3 a to the tank 30. .

  The cooling device according to the first embodiment provided in such a hydraulic excavator is provided with a cooling fan 17, a pressure accumulating device 19, and a pressure accumulating device 19 that generate air for cooling the oil cooler 16, and a cooling fan. And a hydraulic motor 18 for driving the motor 17. The hydraulic motor 18 is operated by return oil from the hydraulic actuator when the hydraulic actuator such as the boom cylinder 5 and the swing motor 3a is operated, and the pressure accumulating device 19 when the hydraulic actuator such as the boom cylinder 5 and the swing motor 3a is not operated. It can be operated with pressure oil accumulated in

  That is, as shown in FIG. 2, in the first embodiment, a branch oil passage 15b branched from the return oil passage 15a is provided, and a pressure accumulating device 19 is connected to the branch oil passage 15b. In the first embodiment, the hydraulic motor 18 is provided in the branch oil passage 15b located downstream of the pressure accumulator 19. Further, this first embodiment is provided in a portion of the branch oil passage 15b located upstream of the pressure accumulator 19, and allows the oil guided to the return oil passage 15a to flow toward the pressure accumulator 19 in the reverse direction. And a relief valve 22 that keeps the pressure in the branch oil passage 15b at a predetermined pressure.

  Further, in the first embodiment, the boom cylinder 5, the swing motor 3 a, etc. are provided in the return oil passage 15 a located between the branch point 31 of the return oil passage 15 a and the branch oil passage 15 b and the oil cooler 16. An opening / closing means for opening / closing the return oil passage 15a in accordance with the non-operation and operation of the hydraulic actuator is provided. The opening / closing means includes, for example, a closed position 20a for closing the return oil passage 15a by a pilot pressure generated by operation of an operation device such as a boom operation device 12a and a turning operation device 12b, a boom operation device 12a, and a turning operation device. When the operating device such as the operating device 12b is neutral, it is composed of a hydraulic pilot type on-off valve 20 having an open position 20b for opening the return oil passage 15a.

  In the first embodiment, the end 15b1 of the branch oil passage 15b downstream of the hydraulic motor 18 is connected to the return oil passage 15a located between the oil cooler 16 and the tank 30.

  In the first embodiment configured as described above, oil discharged from the bottom chamber 5a when the boom cylinder 5 contracts when a boom lowering single operation is performed by operating a hydraulic actuator, for example, a boom operating device, is used for the boom. The oil is guided to the return oil passage 15a through the direction control valve 13a. Further, the opening / closing valve 20 is switched to the closed position 20a in accordance with the operation of the boom operating device 12a, whereby the portion of the return oil passage 15a located upstream of the opening / closing valve 20 is closed. Accordingly, as described above, the oil discharged to the return oil passage 15 a is guided to the branch oil passage 15 b via the branch point 31 and stored in the pressure accumulator 19 via the check valve 21. Further, the oil guided to the branch oil passage 15 b is supplied to the hydraulic motor 18. As a result, the hydraulic motor 18 is operated, and the cooling fan 17 is driven by the hydraulic motor 18. The wind generated by the cooling fan 17 is given to the oil cooler 16 to cool the hydraulic oil.

  In addition, when the boom cylinder 5 that keeps the boom operation device 12a in the neutral position and stops the boom 4 together with the hydraulic actuator, for example, the turning operation device 12b, is not operated, the switching pressure of the on-off valve 20 decreases. The lever 20 is opened, and the oil discharged to the return oil passage 15a is returned to the tank 30 via the valve 20 and the oil cooler 16. At this time, the pressure oil stored in the pressure accumulator 19 is guided to the hydraulic motor 18 through the branch oil passage 15b, and the cooling fan 17 can be driven by operating the hydraulic motor 18.

  In the first embodiment configured as described above, the energy of the return oil is supplied to the hydraulic motor 18 via the return oil passage 15a and the branch oil passage 15b without requiring a pressure converter or the like, and the hydraulic motor 18 is driven. Therefore, a simple configuration can be obtained, and generation of useless energy loss in the pressure transducer or the like can be suppressed. Further, according to the first embodiment, the oil cooler 16 can be cooled by driving the cooling fan 17 without using the engine horsepower regardless of whether the hydraulic actuator, for example, the boom cylinder 5 is operated or not. Thereby, the reduction efficiency of the engine horsepower in the said hydraulic excavator can be improved.

  FIG. 3 is a hydraulic circuit diagram showing a main configuration of the second embodiment of the present invention.

  In the cooling device according to the second embodiment shown in FIG. 3, an end portion 15 b 1 located downstream of the hydraulic motor 18 of the branch oil passage 15 b provided with the hydraulic motor 18 is disposed between the on-off valve 20 and the oil cooler 16. It is configured to be connected to the portion of the return oil passage 15a located. Other configurations are the same as those of the first embodiment, for example.

  According to the cooling device according to the second embodiment configured as described above, the same operation effect as that of the first embodiment can be obtained, and the hydraulic oil whose temperature has increased in the hydraulic motor 18 can be guided to the oil cooler 16, The cooling function of the hydraulic oil can be enhanced.

  In each of the above embodiments, the oil cooler 16 is provided as a heat exchanger that is cooled by the wind generated by the cooling fan 17. However, the radiator or the intercooler may be cooled by the cooling fan 17. Good.

  In each of the above embodiments, the hydraulic pilot type on / off valve 20 is provided as an opening / closing means for opening and closing the return oil passage 15a. Instead of the hydraulic pilot type on / off valve 20, the controller outputs the hydraulic oil. A solenoid valve that opens and closes the return oil passage 15a according to the signal may be provided.

DESCRIPTION OF SYMBOLS 1 Traveling body 2 Revolving body 3 Turning drive device 3a Swing motor 4 Boom 5 Boom cylinder 5a Bottom chamber 6 Arm 7 Arm cylinder 8 Bucket 9 Bucket cylinder 10 Engine 11 Hydraulic pump 12a Boom operating device 12b Swing operating device 13a Boom direction Control valve 13b Direction control valve for turning 15 Return circuit 15a Return oil passage 15b Branch oil passage 15b1 End 16 Oil cooler (heat exchanger)
17 Cooling fan 18 Hydraulic motor 19 Pressure accumulator 20 Open / close valve (open / close means)
20a Closed position 20b Open position 21 Check valve 22 Relief valve 30 Tank 31 Branch point

Claims (5)

An engine, a hydraulic pump driven by the engine, a hydraulic actuator operated by pressure oil discharged from the hydraulic pump, and a direction control valve for controlling a flow of pressure oil supplied from the hydraulic pump to the hydraulic actuator And an operating device for switching the direction control valve, and provided in a construction machine having a heat exchanger,
In the cooling device for a construction machine provided with a cooling fan for blowing air to the heat exchanger,
A pressure accumulator provided in a return oil passage for guiding return oil from the hydraulic actuator;
A hydraulic motor that is provided downstream of the pressure accumulator and drives the cooling fan;
The construction of the construction machine according to claim 1, wherein the hydraulic motor is operated by the return oil when the hydraulic actuator is operated, and can be operated by the pressure oil accumulated in the pressure accumulator when the hydraulic actuator is not operated. Cooling system. The construction machine cooling device according to claim 1,
A branch oil passage branched from the return oil passage is provided,
Connect the pressure accumulator to this branch oil passage,
The hydraulic motor is provided in the branch oil passage located downstream of the pressure accumulator,
Opening / closing means for opening and closing the return oil path when the hydraulic actuator is not operated or activated is provided at a portion of the return oil path located between a branch point between the return oil path and the branch oil path and the tank. A construction machine cooling device characterized by the above. The construction machine cooling device according to claim 2,
The open / close means comprises an open / close valve having a closed position for closing the return oil passage when the operation device is operated and an open position for opening the return oil passage when the operation device is neutral. Cooling system. The construction machine cooling device according to claim 3,
The construction machine cooling device according to claim 1, wherein the heat exchanger comprises an oil cooler provided in a return oil passage located between the on-off valve and the tank. The construction machine cooling device according to claim 4,
A cooling device for a construction machine, wherein an end portion of the branch oil passage located downstream of the hydraulic motor is connected to a portion of a return oil passage located between the on-off valve and the oil cooler.

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