JP2016169795A - Construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a construction machine capable of improving cooling efficiency of working fluid.SOLUTION: A hydraulic shovel includes a controller 34 for controlling a motor 33 based on a detection result of an operation detector so that rotation speed of a fan 32 becomes non-operation time rotation speed N1 or N2 when a hydraulic actuator is not operated and the rotation speed of the fan 32 becomes operation time rotation speed N3 and N4 when the hydraulic actuator is operated. In a situation that a temperature of the working fluid is lower than a reference temperature Tth set in advance, when the non-operation time rotation speeds N1 and N2 and the operation time rotation speed N3 set under the condition that the temperature of the working fluid is equal are compared, the non-operation time rotation speeds N1 and N2 are higher than the operation time rotation speed N3.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a construction machine such as a hydraulic excavator.

  2. Description of the Related Art Conventionally, a construction machine is known that includes an engine, a hydraulic pump that is driven by the power of the engine, and a hydraulic actuator such as a hydraulic cylinder that is operated by supplying hydraulic oil from the hydraulic pump.

  The hydraulic oil generates heat mainly due to the operation of the hydraulic actuator. If the temperature of the hydraulic oil exceeds the allowable temperature, changes in the physical properties of the hydraulic oil (such as a decrease in viscosity) may adversely affect the construction machine.

  Therefore, the construction machine is provided with an oil cooler for cooling the hydraulic oil.

  For example, in the hydraulic excavator described in Patent Document 1, it is determined that the oil cooler provided on the downstream side of the unload circuit through which the hydraulic oil flows when the hydraulic actuator is not operated, and all the hydraulic actuators are in the inactive state. A controller that increases the discharge flow rate of the hydraulic pump in response to the temperature rise of the hydraulic oil.

  According to Patent Document 1, the cooling of the hydraulic oil in the non-operating state of the hydraulic actuator is promoted by increasing the discharge flow rate of the hydraulic pump (the flow rate of the hydraulic oil flowing through the oil cooler) according to the temperature rise of the hydraulic oil. be able to.

JP 2003-269401 A

  However, in the hydraulic excavator described in Patent Document 1, the flow rate of the hydraulic oil from the hydraulic pump is increased in order to promote the cooling of the hydraulic oil, that is, the load of the hydraulic pump is increased.

  Therefore, it is difficult for the hydraulic oil to receive heat generated with an increase in the load of the hydraulic pump and to effectively cool the hydraulic oil.

  An object of the present invention is to provide a construction machine capable of improving the cooling efficiency of hydraulic oil.

  In order to solve the above problems, the present invention is a construction machine, which is a hydraulic pump, a drive source that drives the hydraulic pump, a hydraulic actuator that operates by supplying hydraulic oil from the hydraulic pump, and the hydraulic pressure An oil cooler provided at a position where hydraulic oil derived from the hydraulic actuator when the actuator is operated, and hydraulic oil that flows around the hydraulic actuator when the hydraulic actuator is not operated, and the oil cooler are cooled. A fan for driving, a drive device for driving the fan, an operation detector for detecting whether or not the hydraulic actuator is operating, and a non-operation of the hydraulic actuator based on a detection result of the operation detector Sometimes the rotational speed of the fan is the rotational speed when not operating, and when the hydraulic actuator is operating, And a controller for controlling the drive device so that the rotation speed of the fan becomes the rotation speed during operation, and the temperature of the hydraulic oil is the same in a situation where the temperature of the hydraulic oil is lower than a preset reference temperature When the non-operating rotation speed and the operating rotation speed set under certain conditions are compared, the non-operating rotation speed is higher than the operating rotation speed.

  In the present invention, a fan for cooling the oil cooler and a drive device for driving the fan are provided, and the drive device is provided separately from a drive source for driving the hydraulic pump. Therefore, the cooling capacity for the hydraulic oil can be increased by increasing the rotational speed of the fan without increasing the flow rate of the hydraulic oil by the hydraulic pump. Therefore, the cooling efficiency can be improved while suppressing the thermal influence of the hydraulic pump on the hydraulic oil.

  Furthermore, in the present invention, a controller is provided that controls the drive device so that the rotational speed when the fan is not operating is higher than the rotational speed when the fan is operating in a situation where the temperature of the hydraulic oil is lower than the reference temperature. Therefore, energy saving can be achieved by distributing (smoothing) the load of the construction machine between the non-operating time and the operating time so as to alleviate the load concentration during the operating time.

  In the present invention, the “reference temperature” means the temperature of the hydraulic oil that needs to be rapidly cooled in order not to affect the construction machine.

  Here, the temperature of the hydraulic oil rises due to heat generated when the hydraulic actuator is operated. As described above, if the control is performed to keep the rotational speed of the fan low during the operation of the hydraulic actuator, the hydraulic oil may be heated to a reference temperature or higher and affect the construction machine.

  Therefore, the construction machine further includes a temperature detector that detects the temperature of the hydraulic oil, and the controller is configured such that the temperature of the hydraulic oil is equal to or higher than the reference temperature based on a detection result of the temperature detector. It is preferable that the driving device is controlled so that the operating rotational speed at is higher than the operating rotational speed in a situation where the temperature of the hydraulic oil is lower than the reference temperature.

  According to this aspect, even when the hydraulic actuator is in operation, when the temperature of the hydraulic oil becomes equal to or higher than the reference temperature, the rotational speed of the fan can be increased to rapidly cool the hydraulic oil.

  Therefore, in a situation where the temperature of the hydraulic oil is equal to or higher than the reference temperature, it is possible to cool the hydraulic oil early and reduce the influence of the hydraulic oil on the construction machine.

  Here, in each of the situation where the temperature of the hydraulic oil is lower than the reference temperature and the situation where the temperature is equal to or higher than the reference temperature, it is possible to set the rotation speed during operation to a constant value regardless of the temperature of the hydraulic oil. . However, in this case, the operating speed may be excessive when the temperature of the hydraulic oil is relatively low, while the operating speed may be insufficient when the temperature of the hydraulic oil is relatively high. is there.

  Therefore, in the construction machine, the controller controls the hydraulic oil based on the detection result of the temperature detector in each of a situation where the temperature of the hydraulic oil is lower than the reference temperature and a situation where the temperature is equal to or higher than the reference temperature. It is preferable to control the driving device such that the higher the temperature is, the higher the operating rotational speed is.

  According to this aspect, by setting the rotation speed during operation according to the temperature of the hydraulic oil, it is possible to reduce the excess or deficiency of the rotation speed during operation and operate efficiently while obtaining a greater energy saving effect. The oil can be cooled.

  Here, since the load of the hydraulic pump is low when the hydraulic actuator is not operated, the rotational speed of the drive source is adjusted to be lower than that when the hydraulic actuator is operated. In this situation, since the discharge flow rate from the hydraulic pump is limited to a low flow rate, the flow rate of the working oil passing through the oil cooler is reduced, and the cooling efficiency of the working oil is also lowered.

  Therefore, the construction machine further includes a rotation speed detector that detects the rotation speed of the drive source, and the controller sets the rotation speed of the drive source in advance based on a detection result by the rotation speed detector. The drive device is configured such that the non-operating rotational speed set when lower than the threshold is higher than the non-operating rotational speed set when the rotational speed of the drive source is equal to or greater than the threshold. Is preferably controlled.

  In addition, the construction machine further includes a rotation speed detector that detects a rotation speed of the drive source, and the controller decreases the rotation speed of the drive source based on a detection result by the rotation speed detector. It is preferable to control the driving device so that the rotational speed during operation is high.

  According to these aspects, since the rotational speed of the fan can be set high when the rotational speed of the drive source is relatively low, it is possible to suppress a decrease in the cooling efficiency of the hydraulic oil when the hydraulic actuator is not operated. be able to.

  Further, according to the aspect of switching the non-operating rotation speed between when the driving source rotation speed is higher than the threshold value and when it is lower than the threshold value, compared with the case where the fan rotation speed is set according to the rotation speed of the driving source. Thus, simplification of processing by the controller can be achieved.

  On the other hand, according to the aspect of setting the non-operating rotational speed higher as the rotational speed of the driving source is lower, the cooling efficiency of the hydraulic oil due to the decrease in the discharge flow rate of the hydraulic pump is reduced by the increase in the rotational speed of the fan. Can be efficiently compensated by the increase of.

  According to the present invention, the cooling efficiency of hydraulic oil can be improved.

1 is a side view showing an overall configuration of a hydraulic excavator according to a first embodiment of the present invention. It is a circuit diagram which shows the hydraulic circuit provided in the hydraulic shovel of FIG. It is a block diagram of the control apparatus for controlling the hydraulic circuit of FIG. It is a flowchart which shows the process performed by the controller of FIG. It is a graph which shows the rotation speed at the time of non-operation set by the controller of FIG. It is a graph which shows the rotation speed at the time of the operation | movement set by the controller of FIG. FIG. 6 is a view corresponding to FIG. 5 of a hydraulic excavator according to a second embodiment. FIG. 7 is a view corresponding to FIG. 6 of a hydraulic excavator according to a second embodiment.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. The following embodiments are examples embodying the present invention, and are not of a nature that limits the technical scope of the present invention.

<First Embodiment (FIGS. 1 to 6)>
Referring to FIG. 1, a hydraulic excavator 1 that is an example of a construction machine according to an embodiment of the present invention is provided on a lower traveling body 2 having a pair of left and right crawlers 2 a and on the lower traveling body 2 so as to be able to turn. An upper swing body 3 and an attachment 4 attached to the upper swing body 3 are provided.

  The attachment 4 includes a boom 5 having a base end portion that is attached to the upper swing body 3 so as to be movable up and down, an arm 6 having a base end portion that is rotatably attached to a distal end portion of the boom 5, and And a bucket 7 rotatably attached to the tip.

  The attachment 4 also includes a boom cylinder 8 that drives the boom 5 up and down relative to the upper swing body 3, an arm cylinder 9 that rotates the arm 6 relative to the boom 5, and a bucket 7 that rotates relative to the arm 6. The bucket cylinder 10 is provided.

  Hereinafter, a hydraulic circuit provided in the excavator 1 of FIG. 1 will be described with reference to FIG. The hydraulic circuit operates a boom cylinder 8, a bucket cylinder 10, and a left traveling motor 15 that drives the left crawler 2a of the lower traveling body 2 (hereinafter sometimes collectively referred to as hydraulic actuators 8, 10, and 15). Is for. The hydraulic actuator is not limited to these.

  Specifically, the hydraulic circuit includes a hydraulic pump 11 that discharges hydraulic oil, control valves 12 to 14 that control supply and discharge of hydraulic oil to and from the hydraulic actuators 8, 10, and 15, and an oil cooler that cools the hydraulic oil. 16 and an unloading valve 26.

  The pump line 17 connected to the hydraulic pump 11 is connected to the tank connection line 18 through a center bypass passage that opens only at the neutral position of the control valves 12 to 14, and the tank connection line 18 is a tank that leads to the hydraulic oil tank T. Connected to line 19.

  Input lines 20 to 22 connected in parallel to lines branched from the pump line 17 are connected to the input ports of the control valves 12 to 14, respectively. On the other hand, output lines 23 to 25 are connected to the output ports of the control valves 12 to 14, respectively, and these output lines 23 to 25 are connected to the tank line 19.

  Further, the control valves 12 to 14 are between a neutral position where supply / discharge of hydraulic oil to / from the hydraulic actuators 8, 10, 15 is stopped and two work positions permitting supply / discharge of the hydraulic actuators 8, 10, 15. This is a switchable pilot type directional control valve.

  Specifically, the control valves 12 to 14 are held in a neutral position in a state where pilot pressure is not supplied to the pilot ports. In this state, the input lines 20 to 22 and the output lines 23 to 25 are closed and the center bypass passage is opened. Thereby, the hydraulic oil from the hydraulic pump 11 is guided to the hydraulic oil tank T through the pump line 17, the center bypass passage, the tank connection line 18, and the tank line 19.

  For example, when the control valve 12 is switched to the working position, the pump line 17 and the tank connection line 18 are blocked. In this state, the hydraulic oil from the hydraulic pump 11 is led to the boom cylinder 8 through the input line 20, and the hydraulic oil led out from the boom cylinder 8 is led to the tank line 19 through the output line 23. In this state, when the control valve 13 is held at the neutral position, the input line 21 and the output line 24 are shut off. When the control valve 13 is switched to the working position, the input line 21 and the output line 24 are passed through. Supply / discharge of hydraulic oil to / from the bucket cylinder 10 is executed. The same applies to the control valve 14.

  The unload valve 26 is provided on the upstream side (hydraulic pump 11 side) with respect to the branch point of the line connected to the input lines 20 to 22 in the pump line 17. The unload valve 26 is an electromagnetic valve that can be switched between a permissible position P2 that allows the flow of hydraulic oil through the pump line 17 and an unload position P1 that connects the pump line 17 to the unload line 35. Specifically, the unload valve 26 is held at the unload position P1 when no electrical command is input to the solenoid, while the unload valve 26 is switched to the allowable position P2 when the electrical command is input to the solenoid. Change. The unload line 35 is connected to the tank line 19.

  The oil cooler 16 is provided on the downstream side of the joining point of the output lines 23 to 25 in the tank line 19, the joining point of the tank connection line 18, and the joining point of the unload line 35. In other words, the oil cooler 16 includes the hydraulic oil derived from the hydraulic actuators 8, 10, 15 when the hydraulic actuators 8, 10, 15 are operated, and the hydraulic actuators 8, 10, 15 when the hydraulic actuators 8, 10, 15 are not operated. 10 and 15 is provided at a position where hydraulic fluid flowing around it is guided.

  Hereinafter, with reference to FIG. 2 and FIG. 3, a control device provided in the excavator 1 for controlling the hydraulic circuit shown in FIG. 2 will be described.

  The control device includes an engine (drive source) 27 that drives the hydraulic pump 11, a rotation speed detector 28 that detects the rotation speed of the engine 27, a temperature detector 29 that detects the temperature of the hydraulic oil, and control valves 12 to. 14, an operation means 30 for operating 14, a pressure detector 31 (operation detector) for detecting a pilot pressure output from the operation means 30, a fan 32 for cooling the oil cooler 16, and driving the fan A motor (drive device) 33 and a controller 34 for controlling the motor 33 and the unload valve 26 are provided. In FIG. 3, a state where two elements are electrically connected is indicated by a single solid line, and a state where two elements are mechanically connected is indicated by two solid lines. The flow of hydraulic oil is indicated by a broken line.

  The operation means 30 includes an operation lever (not shown) and a remote control valve (not shown) capable of outputting a pilot pressure corresponding to the operation amount of the operation lever using hydraulic oil discharged from a pilot pump (not shown). ing. The hydraulic excavator 1 includes the same number of operation means 30 (three in the first embodiment) as the control valves 12 to 14, but only one operation means 30 is shown in FIG.

  The pressure detector 31 detects whether or not the hydraulic actuators 8, 10 and 15 are operating by detecting the presence or absence of the pilot pressure output from the operation means 30. The hydraulic excavator 1 includes the same number (three in the first embodiment) of pressure detectors 31 as the operation means 30, but only one pressure detector 31 is shown in FIG. 3 for convenience.

  The controller 34 outputs an electrical command to the solenoid of the unload valve 26 when at least one operation of the hydraulic actuators 8, 10, 15 is detected by the pressure detector 31. As a result, the unload valve 26 switches from the unload position P1 to the allowable position P2.

  On the other hand, the controller 34 stops the output of the electrical command to the solenoid of the unload valve 26 when the pressure detector 31 detects the non-operation of the hydraulic actuators 8, 10, 15. As a result, the unload valve 26 is held (biased) at the unload position P1.

  Further, the controller 34 adjusts the cooling performance of the hydraulic oil by controlling the motor 33 based on the detection results of the rotation speed detector 28, the temperature detector 29, and the pressure detector 31.

  Hereinafter, the control process of the motor 33 executed by the controller 34 will be described with reference to FIGS.

  When the processing by the controller 34 is started, whether or not at least one operation of the operation means 30 is performed based on the detection result by the pressure detector 31, that is, at least one of the hydraulic actuators 8, 10, and 15 is activated. It is determined whether or not there is (step S1).

  Here, if it is determined that all of the hydraulic actuators 8, 10, 15 are inactive (NO in step S 1), the rotational speed of the engine 27 is preset based on the detection result by the rotational speed detector 28. It is determined whether it is smaller than the threshold value Nth (step S2).

  If it is determined that the rotational speed of the engine 27 is lower than the threshold value Nth (in the case of YES at step S2), as shown in FIGS. 4 and 5, the rotational speed of the fan 32 becomes the non-operating rotational speed N1. The motor 33 is controlled (step S3). On the other hand, if it is determined that the rotational speed of the engine 27 is equal to or higher than the threshold value Nth (NO in step S2), the rotational speed of the fan 32 becomes a non-operating rotational speed N2 lower than the non-operating rotational speed N1. The motor 33 is controlled (step S4). The non-operating rotation speeds N1 and N2 are constant rotation speeds regardless of the rotation speed of the engine 27.

  Here, when the rotational speed of the engine 27 is relatively low (lower than the threshold value Nth), the discharge flow rate of the hydraulic pump 11 driven by the engine 27, that is, the flow rate of the hydraulic oil flowing through the oil cooler 16 is high. Since the amount is small, the cooling capacity of the hydraulic oil is reduced. In step S3, in such a case, the rotational speed of the fan 32 is set to a relatively high non-operating rotational speed N1, thereby preventing the hydraulic oil cooling capacity from being lowered.

  On the contrary, when the rotational speed of the engine 27 is relatively high (the threshold value Nth or more), the discharge flow rate of the hydraulic pump 11 driven by the engine 27, that is, the flow rate of the hydraulic oil flowing through the oil cooler 16 is high. Since there are many, the cooling capacity of hydraulic fluid becomes comparatively high. In step S4, in such a case, the fan 32 is prevented from rotating excessively by maintaining the rotational speed of the fan 32 at a relatively low non-operating rotational speed N2.

  For example, when a configuration (for example, mode selection means) that can switch the engine 27 between an idle engine speed and a higher engine speed is provided, between the two engine speeds. By setting the threshold value Nth, the rotational speed of the fan 32 can be switched according to the rotational speed.

  When step S3 or step S4 described above is executed, the process returns.

  On the other hand, if it is determined in step S1 that at least one of the operating means 30 is operated, that is, at least one of the hydraulic actuators 8, 10, 15 is operating, based on the detection result by the temperature detector 29. It is determined whether or not the temperature of the hydraulic oil is lower than a preset reference temperature Tth (step S5).

  Here, the reference temperature Tth is a temperature of hydraulic oil that is set in advance as a temperature that needs to be rapidly cooled so as not to affect the excavator 1.

  If it is determined in step S5 that the temperature of the hydraulic oil is lower than the reference temperature Tth, the motor 33 is controlled so that the rotational speed of the fan 32 becomes the operating rotational speed N3 as shown in FIG. Step S6). The operating speed N3 is a constant speed regardless of the temperature of the hydraulic oil.

  Here, the operating rotation speed N3 is higher than the non-operating rotation speeds N1 and N2 of the fan 32 set when all the hydraulic actuators 8, 10, and 15 are not operated under the condition that the temperature of the hydraulic oil is the same. The rotation speed is low. In other words, in a situation where the temperature of the hydraulic oil is lower than the reference temperature Tth, when comparing the non-operating rotational speeds N1 and N2 and the operating rotational speed N3 set under the condition that the hydraulic oil temperature is the same. The non-operating speed N1, N2 is higher than the operating speed N3. FIG. 6 shows only the low non-operating speed N2 among the non-operating speeds N1 and N2 in order to show the magnitude relationship between the operating speed N3 and the non-operating speeds N1 and N2. It is indicated by a two-dot chain line.

  As a result, the hydraulic excavator 1 (motor 33) is loaded when the hydraulic actuators 8, 10 and 15 are operated in a situation where the hydraulic oil does not need to be rapidly cooled (a situation where the hydraulic oil temperature is lower than the reference temperature Tth). Can be reduced.

  On the other hand, when it is determined in step S5 that the temperature of the hydraulic oil is equal to or higher than the reference temperature Tth, the motor 33 is controlled so that the rotational speed of the fan 32 is higher than the operating rotational speed N3. (Step S7). The operating rotational speed N4 is a constant rotational speed regardless of the temperature of the hydraulic oil.

  Thereby, in a situation where the hydraulic oil needs to be rapidly cooled (a situation where the temperature of the hydraulic oil is equal to or higher than the reference temperature Tth), the cooling of the hydraulic oil can be promoted by increasing the rotational speed of the fan 32.

  In FIG. 6, the operating rotational speed N4 is shown as a rotational speed lower than the non-operating rotational speed N2, but the operating rotational speed N4 is set to the non-operating rotational speed in order to cool the hydraulic oil rapidly. The number of rotations can be set equal to or higher than N1 and N2.

  As described above, the fan 32 for cooling the oil cooler 16 and the motor 33 for driving the oil cooler 16 are provided, and the motor 33 is provided separately from the engine 27 for driving the hydraulic pump 11. Therefore, the cooling capacity for the hydraulic oil can be increased by increasing the rotational speed of the fan 32 without increasing the flow rate of the hydraulic oil by the hydraulic pump 11. Therefore, the cooling efficiency can be improved while suppressing the thermal influence of the hydraulic pump 11 on the hydraulic oil.

  Further, in the present invention, the controller that controls the drive device so that the non-operating rotation speeds N1 and N2 of the fan 32 are higher than the fan operating rotation speed N3 in a situation where the temperature of the hydraulic oil is lower than the reference temperature Tth. 34 is provided. Therefore, energy saving can be achieved by distributing (smoothing) the load of the construction machine between the non-operating time and the operating time so as to alleviate the load concentration during the operating time.

  Moreover, according to 1st Embodiment, there can exist the following effects.

  Even when the hydraulic actuators 8, 10, 15 are in operation, when the temperature of the hydraulic oil becomes equal to or higher than the reference temperature Tth, the rotational speed of the fan 32 can be increased to rapidly cool the hydraulic oil.

  Therefore, in addition to the above-described effects, in a situation where the temperature of the hydraulic oil is equal to or higher than the reference temperature Tth, the influence of the hydraulic oil on the excavator 1 can be reduced by cooling the hydraulic oil at an early stage.

  When the rotational speed of the engine 27 is relatively low, the rotational speed of the fan 32 can be set high (set to the non-operating rotational speed N1). For this reason, even when the hydraulic actuators 8, 10, 15 are not operated, the rotational speed of the engine 27 is reduced and the discharge flow rate of the hydraulic pump 11 is reduced.

  Further, in order to switch the non-operating rotational speeds N1 and N2 between when the rotational speed of the engine 27 is higher and lower than the threshold value Nth, according to the rotational speed of the engine 27 as in the second embodiment described later. Compared with the case where the rotational speed of the fan 32 is set, the processing by the controller 34 can be simplified.

<Second Embodiment (FIGS. 7 and 8)>
The controller 34 in the first embodiment has a constant non-operating rotational speed N1 regardless of the rotational speed of the engine 27 in a situation where the rotational speed of the engine 27 is less than the threshold Nth when the hydraulic actuators 8, 10, and 15 are not operating. Is set, and a constant non-operating speed N2 is set regardless of the speed of the engine 27 when the speed of the engine 27 is equal to or greater than the threshold value Tth.

  On the other hand, as shown in FIG. 7, the controller 34 in the second embodiment omits the threshold value of the rotational speed of the engine 27, and the lower the rotational speed of the engine 27, the higher the rotational speed when the fan 32 is not operating. The motor 33 is controlled. Specifically, the controller 34 sets the non-operating rotational speed along a straight line characteristic as shown by a solid line in FIG. 7, or the non-operating rotational speed along a curved line characteristic as shown by a two-dot chain line. Can be set.

  In this case, in the flowchart shown in FIG. 4, after it is determined as YES in step S <b> 1, the non-operating rotation speed of the fan 32 corresponding to the rotation speed of the engine 27 is set based on the detection result by the rotation speed detector 28. The motor 33 may be controlled based on the non-operating rotation speed.

  In this way, it is possible to efficiently compensate for the decrease in the cooling efficiency of the hydraulic oil due to the decrease in the discharge amount of the hydraulic pump 11 by the increase in the cooling efficiency due to the increase in the rotation speed of the fan 32.

  Further, the controller 34 in the first embodiment, when the hydraulic actuators 8, 10, 15 are operated, in a situation where the temperature of the hydraulic oil is lower than the reference temperature Tth, the constant rotational speed N <b> 3 during operation regardless of the temperature of the hydraulic oil. It is set, and a constant operating rotational speed N4 is set regardless of the temperature of the hydraulic oil when the hydraulic oil temperature is equal to or higher than the reference temperature Tth.

  On the other hand, as shown in FIG. 8, the controller 34 in the second embodiment is based on the detection result by the temperature detector in each of the situation where the temperature of the hydraulic oil is lower than the reference temperature Tth and the situation where the temperature is higher than the reference temperature Tth. The motor 33 is controlled such that the higher the operating oil temperature is, the higher the operating speeds N3 and N4 of the fan 32 are.

  In this case, the operating speed N3 can be set in step S6 in the flowchart shown in FIG. 4, and the operating speed N4 can be set in step S7.

  Also in the second embodiment, the operating rotation speed N4 of the fan 32 set in a situation where the temperature of the hydraulic oil is equal to or higher than the reference temperature Tth is a fan set in a situation where the temperature of the hydraulic oil is lower than the reference temperature Tth. It is higher than the operating speed N3 of 32.

  Further, the operating rotation speed N3 is set when the hydraulic actuators 8, 10, and 15 are not operated under the condition that the temperature of the hydraulic oil is the same, and when the fan 32 indicated by a two-dot chain line in FIG. The rotational speed is lower than the rotational speed.

  It should be noted that the operating rotational speed N4 may be set equal to or higher than the non-operating rotational speed, as in the first embodiment.

  In addition, this invention is not limited to the said embodiment, For example, the following aspects can also be employ | adopted.

  In the above embodiment, the engine 27 is cited as an example of a drive source for driving the hydraulic pump 11, but the drive source is not limited to the engine 27 as long as it drives the drive shaft of the hydraulic pump 11 to rotate. For example, an electric motor can be employed as the drive source.

  In the above embodiment, the example in which the three hydraulic actuators 8, 10, and 15 are provided has been described. However, it is sufficient that at least one hydraulic actuator is provided. In this case, if the controller determines that all the hydraulic actuators are inactive, the rotational speed of the fan 32 becomes the rotational speed and the rotational speed when not operating, and at least one of all the hydraulic actuators is operating. If determined, the motor 32 may be controlled so that the rotational speed of the fan 32 becomes the rotational speed during operation.

  In the above-described embodiment, whether or not the hydraulic actuators 8, 10, and 15 are operating is detected by detecting the presence or absence of pilot pressure from the operation means 30. It is also possible to detect whether or not the hydraulic actuator is operating by detecting whether or not the hydraulic actuators 8, 10, and 15 are operating.

  The controller 34 increases the non-operating speed of the fan 32 as the rotational speed of the engine 27 is lower as in the second embodiment, and the fan 32 operates regardless of the temperature of the hydraulic oil as in the first embodiment. The motor 33 may be controlled so that the rotational speed during operation is constant. On the other hand, the controller 34 is configured such that the non-operating rotational speed of the fan 32 is constant regardless of the rotational speed of the engine 27 as in the first embodiment, and the higher the temperature of the hydraulic oil as in the second embodiment, It is also possible to control the motor 33 so that the rotational speed at the time of operation of 32 becomes high.

  The construction machine is not limited to a hydraulic excavator, and may be a crane and a dismantling machine.

N1, N2 Non-operating speed N3, N4 Operating speed Nth Engine speed threshold Tth Reference temperature 1 Hydraulic excavator (an example of construction machinery)
8 Boom cylinder (an example of a hydraulic actuator)
10 Bucket cylinder (an example of a hydraulic actuator)
11 Hydraulic pump 15 Left travel motor (an example of hydraulic actuator)
16 Oil cooler 27 Engine (example of drive source)
28 Rotational speed detector 29 Temperature detector 31 Pressure detector (an example of an operation detector)
32 fan 33 motor (example of drive unit)
34 Controller

Claims (5)

A construction machine,
A hydraulic pump;
A drive source for driving the hydraulic pump;
A hydraulic actuator that operates by supplying hydraulic oil from the hydraulic pump;
An oil cooler provided at a position where hydraulic oil derived from the hydraulic actuator when the hydraulic actuator is operated, and hydraulic oil that flows around the hydraulic actuator when the hydraulic actuator is not operated are guided;
A fan for cooling the oil cooler;
A driving device for driving the fan;
An operation detector for detecting whether the hydraulic actuator is operating;
Based on the detection result of the operation detector, when the hydraulic actuator is not operated, the rotational speed of the fan is the non-operating rotational speed, and when the hydraulic actuator is operated, the rotational speed of the fan is the operating rotational speed. And a controller for controlling the driving device.
In a situation where the temperature of the hydraulic oil is lower than a preset reference temperature, when comparing the non-operating rotation speed and the operating rotation speed set under the condition that the temperature of the hydraulic oil is the same, The construction machine, wherein the non-operating speed is higher than the operating speed. The construction machine further includes a temperature detector that detects a temperature of the hydraulic oil,
The controller, based on the detection result of the temperature detector, the operating rotational speed in a situation where the temperature of the hydraulic oil is equal to or higher than the reference temperature, in a situation where the temperature of the hydraulic oil is less than the reference temperature The construction machine according to claim 1, wherein the drive device is controlled to be higher than the rotation speed during operation.   In each of the situation where the temperature of the hydraulic oil is lower than the reference temperature and the situation where the temperature of the hydraulic oil is equal to or higher than the reference temperature, the controller increases the temperature of the hydraulic oil based on the detection result of the temperature detector. The construction machine according to claim 2, wherein the driving device is controlled so as to increase a rotational speed. The construction machine further includes a rotation speed detector that detects the rotation speed of the drive source,
The controller is configured such that the non-operating rotational speed set when the rotational speed of the drive source is lower than a preset threshold based on a detection result by the rotational speed detector is the rotational speed of the drive source. The construction machine according to any one of claims 1 to 3, wherein the driving device is controlled to be higher than the non-operating rotation speed set when is equal to or greater than the threshold value. The construction machine further includes a rotation speed detector that detects the rotation speed of the drive source,
4. The controller according to claim 1, wherein the controller controls the drive device so that the non-operating rotation speed increases as the rotation speed of the drive source decreases based on a detection result of the rotation speed detector. The construction machine according to item 1.

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