Working machine

A working machine includes a machine body, an engine provided on the machine body, a radiator to cool a coolant supplied to the engine, a first fan provided on one directional surface side of the radiator, the first fan being rotatable in either one of a first direction to suck external air to an interior of the machine body and a second direction to generate an air flow for discharging air from the interior of the machine body to an exterior of the machine body, and a second fan provided on the other directional surface side of the radiator and configured to be rotated in the second direction.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priorities to Japanese Patent Application No. 2020-137189 filed on Aug. 15, 2020, Japanese Patent Application No. 2020-137190 filed on Aug. 15, 2020, and Japanese Patent Application No. 2020-137191 filed on Aug. 15, 2020. The entire contents of this application are hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a working machine such as a skid steer loader or a compact track loader.

Description of the Related Art

A working machine disclosed in Japanese Patent Publication No. 2009-92046 (referred to as Patent Document 1) is already known.

The working machine disclosed in Patent Document 1 is provided with a cooling fan for cooling a radiator and the like, and a switching mechanism for switching a rotational direction of the cooling fan between a normal direction and a reverse direction.

In addition, a working machine disclosed in Japanese Patent Publication No. 2001-182535 (referred to as Patent Document 2) is already known.

The working machine disclosed in Patent Document 2 has a cooling fan for cooling a radiator and the like, and a controller for controlling switching of a rotational direction of the cooling fan between a normal direction and a reverse direction.

BRIEF SUMMARY OF THE INVENTION

In the working machine disclosed in Patent Document 1, the radiator and the like can be cooled by rotating the cooling fan in the normal direction, and dusts on the radiator and the like can be blown away by rotating the cooling fan in the reverse direction. However, simply rotating the cooling fan in the reverse direction may not provide a sufficient air capacity to blow away the dusts. For example, the cooling fan has an insufficient air capacity at the central portion thereof and its vicinity. Thus, even when the cooling fan is rotated in the reverse direction, the unblown dusts are accumulated to deteriorate a cooling performance.

In addition, when the cooling fan is rotated in the reverse direction for a long period of time, a negative pressure (that is, a suction pressure) may be generated on a hood from which the wind blows out, and thus it may be impossible to blow off the dusts.

In the working machine disclosed in Patent Document 2, the radiator and the like can be cooled by rotating the cooling fan in the normal direction, and the dusts on the radiator and the like can be blown away by rotating the cooling fan in the reverse direction. However, the reverse rotation cannot be stopped even in a case some abnormality occurred while the cooling fan rotates in the reverse direction.

In view of the above-mentioned problems, the present invention intends to provide a working machine including a fan having a sufficient air capacity for blowing off the dusts.

In addition, the present invention intends to provide a working machine including a fan capable of blowing off the dusts reliably for a long time.

In addition, the present invention intends to provide a working machine including a fan allowed to stop its rotation as needed when the fan is rotated in the reverse direction.

A working machine according to one aspect of the present invention includes a machine body, an engine provided on the machine body, a radiator to cool a coolant supplied to the engine, a first fan provided on one directional surface side of the radiator, the first fan being rotatable in either one of a first direction to suck external air to an interior of the machine body and a second direction to generate an air flow for discharging air from the interior of the machine body to an exterior of the machine body, and a second fan provided on the other directional surface side of the radiator and configured to be rotated in the second direction.

The working machine further includes a controller to control drive of the first and second fans. The controller is configured or programmed to stop the second fan when the first fan rotates in the first direction, and to drive the second fan when the first fan rotates in the second direction.

The working machine further includes a condenser to condense a refrigerant for an air conditioner provided on the machine body. The condenser is provided between the radiator and the second fan.

The air capacity of the first fan rotating in the first direction is larger than that of the first fan rotating in the second direction.

The first fan and the second fan have respective rotary axes coaxial to each other.

The second fan is diametrically smaller than the first fan.

The first fan is a hydraulic fan driven by hydraulic pressure. The second fan is an electric fan driven by electricity.

The working machine further includes a fan cover to cover an upper side of the second fan opposite to the condenser. The second fan is provided on a lower side thereof with a blade, and on an upper side thereof with a motor for rotating the blade. An upper surface of the fan includes a flat surface and an uneven surface. The flat surface overlaps the motor in plan view.

A working machine according to one aspect of the present invention includes a machine body, an engine provided on the machine body, a radiator to cool a coolant supplied to the engine, a first fan provided on one directional surface side of the radiator, the first fan being rotatable in either one of a first direction to suck external air to an interior of the machine body and a second direction to generate an air flow for discharging air from the interior of the machine body to an exterior of the machine body, and a controller to control drive of the first fan. The controller is configured or programmed to control drive of the first fan rotating in the second direction in such a way that a process of actions including a speed-increasing action to increase a rotation speed of the first fan and a speed-reducing action to reduce the rotation speed of the first fan increased by the speed-increasing action is repeated in a predetermined period.

The controller is configured or programmed to increase the rotation speed of the first fan rotating in the second direction to a maximum rotation speed during the speed-increasing action, and to reduce the rotation speed of the first fan rotating in the second direction to a minimum rotation speed during the speed-reducing action.

The controller is configured or programmed to control drive of the first fan rotating in the second direction during the process of actions in such a way that a time for the rotation of the first fan at the maximum rotation speed is longer than a time for the rotation of the first fan at the minimum rotation speed.

The controller is configured or programmed to control drive of the first fan rotating in the second direction during the process of actions in such a way that a time for the rotation of the first fan at the minimum rotation speed is longer than a time for the rotation of the first fan at the maximum rotation speed.

The working machine further includes a second fan provided on the other directional surface side of the radiator and configured to be rotated in the second direction. The controller is configured or programed to drive the second fan continuously during the predetermined period of repeating the process of actions.

The controller is configured or programed to perform a first switching action to switch the rotation direction of the first fan from the first direction to the second direction before start of repeating the process of actions, and to perform a second switching action to switch the rotation direction of the first fan from the second direction to the first direction after end of repeating the process of actions.

The controller is configured or programed to perform the first switching action and the second switching action when the first fan rotates at the minimum rotation speed.

The controller is configured or programed to start drive of the second fan at a time shifted from that of performing the first switching action.

The controller is configured or programed to start drive of the second fan before performing the first switching action.

The controller is configured or programed to stop drive of the second fan at a time shifted from that of performing the second switching action.

The controller is configured or programed to stop drive of the second fan after performing the second switching action.

A working machine according to one aspect of the present invention includes a machine body, an engine provided on the machine body, a radiator to cool a coolant supplied to the engine, a fan provided on one directional surface side of the radiator, the first fan being rotatable in either one of a first direction to suck external air to an interior of the machine body and a second direction to generate an air flow for discharging air from the interior of the machine body to an exterior of the machine body, and a controller to control drive of the fan. The controller is configured or programmed to make the fan selectively perform either a basic action to finish the rotation of the fan in the second direction after a predetermined period elapses from start of the rotation of the fan in the second direction or a canceling action to interrupt the rotation of the fan in the second direction when an interruption condition is satisfied in the predetermined period.

The controller is configured or programed to make the fan perform the canceling action in such a way that the rotation direction of the fan is switched to the first direction after the rotation speed of the fan rotating in the second direction is gradually reduced.

The controller is configured or programed to make the fan perform the canceling action in such a way that the rotation of the fan is stopped after the rotation speed of the fan rotating in the second direction is gradually reduced.

The controller is configured or programed to make the fan perform the canceling action in such a way that the rotation of the fan is stopped after a predetermined period elapses since the reduced rotation speed of the fan rotating in the second direction becomes a minimum rotation speed.

The working machine further includes a working device attached to the machine body, a first sensor to detect a temperature of operation fluid for driving the working device, and a second sensor to detect a temperature of the coolant for cooling the engine. The controller is configured or programed to define a state where the temperature detected by the first sensor or the second sensor deviates from a predetermined temperature range as the satisfied interruption condition for determination to perform the canceling action.

The controller is configured or programmed to define stopping of the engine as the satisfied interruption condition for determination to perform the canceling action.

The working machine further includes a switch manually operable to be shifted between an ON state to allow the fan to rotate in the second direction and an OFF state to hinder the fan from rotating in the second direction. The controller is configured or programmed to define the setting of the switch in the OFF state as the satisfied interruption condition for determination to perform the canceling action.

The working machine further includes a detector to detect a fault of a component relevant to the drive of the fan. The controller is configured or programmed to define a state where a fault is detected by the detector as the satisfied interruption condition for determination to perform the canceling action.

The working machine further includes an exhaust gas purificator including a filter to trap particulate matters included in exhaust gas from the engine, and a filter regenerator to burn the particulate matters trapped by the filter. The controller is configured or programed to define a state where the filter regenerator performs a filter regeneration process to burn the particulate matters as the satisfied interruption condition for determination to perform the canceling action.

The working machine further includes a setting member to set a rotation speed of the engine, and a rotation speed sensor to detect the rotation speed of the engine. The controller is configured or programed to define a state where a differential value obtained by subtracting an actual rotation speed detected by the rotation speed sensor from an instructed rotation speed set by the setting member as the satisfied interruption condition for determination to perform the canceling action.

The working machine further includes a working device attached to the machine body, a first sensor to detect a temperature of operation fluid for driving the working device, a second sensor to detect a temperature of the coolant for cooling the engine, and a fault detector to detect a fault of the first sensor or the second sensor. The controller is configured or programed to define a state where a fault is detected by the fault detector as the satisfied interruption condition for determination to perform the canceling action.

The working machine further includes a cabin mounted on the machine body, and an air conditioner to feed a temperature-adjusted air into the cabin. The controller is configured or programed to define a state where the air conditioner is driven as the satisfied interruption condition for determination to perform the canceling action.

Due to the working machine, the air capacity generated by the rotation of the second fan can compensate for an insufficient air capacity provided by the rotation of the first fan alone (for example, the insufficient air capacity of the first fan at the central portion thereof and its vicinity), so that a sufficient air capacity can be obtained for blowing dusts toward the outside of the machine body.

Due to the working machine, by repeating the increase and decrease of the number of rotations while the first fan is rotating in the second direction, a negative pressure (that is, a suction pressure) can be prevented from being generated in a portion from which the wind of the first fan blows out. Thus, the dusts can be blown away reliably for a long time.

Due to the working machine, while the fan for cooling is rotating in the reverse direction (that is, a second direction) opposite to the direction for cooling, the rotation in the reverse direction can be stopped as needed. In this manner, problems (such as overheating of the equipment) that may occur due to continuous rotation of the fan in the reverse direction can be eliminated.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A working machine according to a preferred embodiment of the present invention will be described below.

FIG.12shows a side view of the working machine according to the present invention. InFIG.12, a compact track loader is shown as an example of the working machine. However, the working machine according to the present invention is not limited to the compact track loader, but may be another typed loader, such as a skid steer loader, for example. In addition, the working machine may be one other than the loader.

As shown inFIG.12, the working machine1includes a machine body2, a cabin3, a working device4, and traveling devices5. In the embodiment of the present invention, a forward direction of a driver sitting on a driver seat8of the working machine1(a left side inFIG.12) is referred to as the front, a rearward direction of the driver (a right side inFIG.12) is referred to as the rear, a leftward direction of the driver (a front surface side ofFIG.12) is referred to as the left, and a rightward direction of the driver (a back surface side ofFIG.12) is referred to as the right. In addition, a horizontal direction, which is orthogonal to a fore-and-aft direction K1, is referred to as a machine-width direction K2.

The cabin3is mounted on the machine body2. The cabin3incorporates the driver seat8. The working machine1is provided with an air conditioner (not shown in the drawings) configured to supply temperature-conditioned air into the cabin3. An operation of the air conditioner is controlled by a controller60to be described later. The traveling devices5are provided respectively on the left and right sides of the machine body2. In the present embodiment, a crawler-type (including a semi-crawler type) traveling device is adopted as each of the traveling devices5. However, a wheel-type traveling device having front wheels and rear wheels may be adopted.

The working device4is attached to the machine body2. The working device4includes booms10, a working tool11, lift links12, control links13, boom cylinders14, and bucket cylinders15. The boom cylinders14and the bucket cylinders15are hydraulic cylinders, and are driven (telescoped) by operation fluid supplied from a hydraulic pump.

The booms10are vertically swingably arranged on right and left sides of the cabin3. The working tool11is a bucket, for example. The bucket11is vertically movably arranged on tip portions (that is, front end portions) of the booms10. The lift links12and the control links13support base portions (that is, rear portions) of the booms10so as to allow the booms10to swing up and down. The booms10are raised and lowered by telescoping the boom cylinders14. The bucket11is swung by telescoping the bucket cylinders15.

Front portions of the right and left booms10are connected to each other by a deformed connecting pipe. Base portions (that is, rear portions) of the booms10are connected to each other by a circular connecting pipe.

The lift links12, the control links13, and the boom cylinders14are arranged on right and left sides of the machine body2distributedly in correspondence to the right and left booms10.

The lift links12are extended vertically from rear portions of the base portions of the booms10. Upper portions (one end portions) of the lift links12are pivoted on the rear portions of the base portions of the booms10pivotally supported on the rear portions of the base portions of the booms10via respective pivot shafts (referred to as first pivot shafts)16turnably around lateral axes defined by the pivot shafts16. Lower portions (the other end portions) of the lift links12are pivotally supported on the rear portion of the machine body2via respective pivot shafts (referred to as second pivot shafts)17turnably around lateral axes defined by the pivot shafts17. The second pivot shafts17are provided below the first pivot shafts16.

Upper portions of the boom cylinders14are pivotally supported on respective pivot shafts (referred to as third pivot shafts)18turnably around lateral axes defined by the pivot shafts18. The third pivot shafts18are provided at the base portions of the booms10, especially, at front portions of the base portions. Lower portions of the boom cylinders14are pivotally supported on respective pivot shafts (referred to as fourth pivot shafts)19turnably around lateral axes defined by pivot shafts19. The fourth pivot shafts19are provided at a lower portion of the rear portion of the machine body2and below the third pivot shafts18.

The control links13are provided in front of the lift links12. One ends of the control links13are pivotally supported on respective pivot shafts (referred to as fifth pivot shafts)20turnably around lateral axes defined by the pivot shafts20. In the machine body2, the fifth pivot shafts20are disposed forward from the lift links12. The other ends of the control links13are pivotally supported on respective pivot shafts (referred to as sixth pivot shafts)21turnably around lateral axes defined by the pivot shafts21. In the working machine2, the sixth pivot shafts21are disposed forwardly upward from the second pivot shafts17.

By telescoping the boom cylinders14, the booms10are swung up and down around the first pivot shafts16with the base portions of the booms10supported by the lift links12and the control links13, thereby raising and lowering the tip portions of the booms10. The control links13are swung up and down around the fifth pivot shafts20by the vertical swinging of the booms10. The lift links12are swung back and forth around the second pivot shafts17by the vertical swinging of the control links13.

An alternative working tool instead of the bucket11can be attached to the front portions of the booms10. For example, an attachment (specifically, an auxiliary attachment), such as a hydraulic crusher, a hydraulic breaker, an angle broom, an earth auger, a pallet fork, a sweeper, a mower, or a snow blower, may serve as the alternative working tool.

A connecting member50is provided at the front portion of the left boom10. The connecting member50is a device configured to connect a hydraulic equipment attached to the auxiliary attachment to a first piping member such as a pipe provided on the left boom10. Specifically, the first piping member can be connected to one end of the connecting member50, and a second piping member connected to the hydraulic equipment of the auxiliary attachment can be connected to the other end. In this manner, an operation fluid flowing in the first piping member is passed through the second piping member and is supplied to the hydraulic equipment.

The bucket cylinders15are arranged close to the front portions of the booms10, respectively. The bucket11is swung by telescoping the bucket cylinders15.

As shown inFIG.1, a prime mover22is mounted in a rear inside portion of the machine body2. An engine (specifically, an internal combustion engine), such as a diesel engine or a gasoline engine, an electric motor, or the like may serve as the prime mover22. In the embodiment, the prime mover22is an engine, specifically, a diesel engine. In the following description, the prime mover22is referred to as the engine22. In addition, a space inside the machine body2in which the engine22is mounted (housed) is referred to as an engine room ER. The engine room ER is covered by the hood9from above.

An exhaust gas purification device23provided with a filter (Diesel Particulate Filter: DPF) that collects particulate matters contained in the exhaust gas from the engine22is arranged in the engine room ER. The working machine1is provided with a filter regenerator (not shown in the drawings) that burns particulate matters trapped and collected in the filter of the exhaust gas purification device23. The filter regenerator performs a filter regeneration (DPF regeneration) processing based on control by the controller60to be described below. The filter regeneration process is carried out by raising a temperature of the DPF to or above a predetermined temperature, thereby burning off accumulated PM to gasify it, and discharging the gas to the environment along with the exhaust gas. The DPF regeneration is carried out, for example, by post-injection of fuel. The post-injection is an operation to facilitate the temperature rising of the DPF by injecting fuel into the gas after the combustion.

As shown inFIG.1, a radiator24is arranged above the engine22. The radiator24cools a coolant supplied to the engine22. The radiator24is arranged, so that one side faces downward and the other side faces upward. The radiator24is arranged slantwise downwardly from the front to the rear.

A first fan25is arranged above the engine22and below the radiator24. The first fan25is arranged on one directional surface side (that is, a lower surface side) of the radiator24. In the present embodiment, the first fan25is a hydraulic fan configured to be driven by a hydraulic pressure. The first fan25is driven by a first motor28. The first motor28is a hydraulic motor configured to be operated by operation fluid. An output shaft of the first motor28(hereinafter referred to as “the first output shaft28a”) extends upward (that is, diagonally upward and backward). A first blade29is attached to an upper portion of the first output shaft28a. That is, in the first fan25, the first blade29is arranged on the upper side, and the first motor28for rotating the first blade29is arranged on the lower side.

The first blade29rotates about the first output shaft28awith the rotation of the first output shaft28a. A rotary center axis of the first output shaft28a(hereinafter referred to as “the first rotation shaft center axis CL1”) is inclined upwardly rearward. In this manner, a rotational plane generated by the rotation of the first blade29is inclined rearwardly downward, so that the rotational plane is substantially parallel to one directional side surface of the radiator24. As shown inFIGS.1and2, a first shroud32is arranged around the first blade29. The first shroud31is formed in a cylindrical shape and extends along the periphery of the first blade29.

The first fan25is rotatable in first and second directions opposite to each other. The rotational direction of the first fan25means the rotational direction of the first blade29around the first output shaft28a. As shown inFIG.3A, when the first fan25rotates in the first direction, the first fan25generates an airflow (hereinafter referred to as “the first airflow FL1”) that brings the outside air into the machine body2. As shown inFIG.3B, when the first fan25rotates in the second direction, the first fan25generates an airflow (hereinafter referred to as “the second airflow FL2”) that discharges the air inside the machine body2to the outside of the machine body2. That is, the rotation in the first direction generates the first airflow FL1, and the rotation in the second direction generates the second airflow FL2. The generation of the first airflow FL1allows the outside air (that is, the air outside the machine body2) to be introduced into the engine room ER. The generation of the second airflow FL2causes the air inside the engine room ER to be discharged to the outside of the machine body2.

The air capacity of the first fan25rotated in the first direction is larger than the air capacity of the first fan25rotated in the second direction. This difference in air capacity can be achieved, for example, by making the shapes of the blades viewed from the front side (that is, a radiator24side) different from the shapes of the blades viewed from the back side (that is, an opposite side to the radiator24). In addition, it may be achieved by a method of making the rotation speed in the first direction different from the rotation speed in the second direction.

As shown inFIGS.1and2, a second fan26is arranged on the other directional surface side (that is, an upper surface side) of the radiator24. In the present embodiment, the second fan26is an electric fan configured to be driven by electric power. The power to drive the second fan26is supplied from a battery or the like mounted on the machine body2. The second fan26is driven by the second motor30. The second motor30is an electric motor configured to be operated by electric power. The output shaft of the second motor30(hereinafter referred to as “the second output shaft30a”) extends downward (specifically, diagonally forwardly downward). A second blade31is attached to a lower portion of the second output shaft30a. That is, in the second fan26, the second blade31is arranged on the lower side, and the second motor30for rotating the second blade31is arranged on the upper side.

The second blade31rotates around the second output shaft30awith the rotation of the second output shaft30a. The rotary center axis of the second output shaft30a(hereinafter referred to as the “second rotation shaft center axis CL2”) is inclined upwardly rearward. In this manner, a rotational plane generated by the rotation of the second blade31is inclined rearwardly downward, so that the rotational plane is substantially parallel to one directional side surface of the radiator24.

As shown inFIGS.1and2, a second shroud38is arranged around the second blade31. The second shroud38is formed in a cylindrical shape and extends along the periphery of the second blade31. As shown inFIGS.1and4, a protective cover33is provided at an upper portion of the second shroud38. The protective cover33has a grid shape and covers the upper surface of the second blade31. The second motor30is attached to the center of the protective cover33. The second motor30protrudes upward from the protective cover33.

As shown inFIG.3, the first rotation shaft center axis CL1of the first output shaft28aand the second rotation shaft center CL2of the second output shaft30amay be coaxial to each other. However, in this embodiment as shown inFIG.1, the first rotation shaft center CL1and the second rotation shaft center CL2are offset in the fore-and-aft direction. Specifically, in the embodiment shown inFIG.1, the first rotation shaft center CL1is disposed forward from the second rotation shaft center CL2. However, even when arranged in this manner, it is preferable to match the first rotation shaft center CL1with the second rotation shaft center CL2in the machine-width direction K2, as shown inFIG.2.

As shown inFIG.3, the rotational plane generated by the rotation of the first blade29of the first fan25and the rotational plane generated by the rotation of the second blade31of the second fan26are parallel to each other. A diameter of the second fan26(that is, a diameter of the second blade31) is smaller than a diameter of the first fan25(that is, a diameter of the first blade29).

The second fan26rotates in the above-described second direction. That is, the second fan26rotates in the direction to generate the second airflow FL2(that is, the airflow for discharging the air inside the machine body2to the outside of the machine body2). The rotational direction of the second fan26means the rotational direction the second blade31around the second output shaft30a. In the present embodiment, the second fan26is configured to rotate only in the second direction. In other words, the second fan26is capable of generating the second airflow FL2, but incapable of generating the first airflow FL1.

However, the second fan26needs to be rotatable in at least the second direction. Therefore, the second fan26may be rotatable in the first and second directions. In this case, the second fan26is configured to have a air capacity when rotating in the second direction which is larger than that when rotating in the first direction.

As shown inFIGS.1,2, and3, a condenser27is disposed above the radiator24. The condenser27is disposed between the radiator24and the second fan26. Specifically, the condenser27is disposed above the radiator24and below the second fan26. The condenser27condenses refrigerant of the air conditioner configured to supply temperature-controlled air to the inside of the cabin3mounted on the machine body2.

As shown inFIGS.1and2, the first fan25is arranged inside the duct34. The radiator24, the condenser27, and the second fan26are arranged above the duct34. The engine22is arranged below the duct34. The duct34defines an air flow passage and has an upper opening35and at least one side opening36. The upper opening35faces one directional surface side (that is, the lower surface side) of the radiator24. A first shroud32surrounding the first blade29is fitted in the upper opening35. The at least one side opening36includes a left side opening36L and a right side opening36R. The left side opening36L is joined to a left opening7L formed in a left side wall2L of the machine body2. The right side opening36R is joined to a right opening7R formed in a right side wall2R of the machine body2. A grid plate39L is provided to cover the left opening7L. The right opening7R is provided to cover a grid plate39R.

When the first airflow FL1is generated by the first fan25rotating in the first direction, the outside air is taken into the inside of the machine body2through a ventilation hole40a(seeFIG.6) provided in a later-discussed fan cover40, passes through the condenser27and the radiator24, and then enters the duct34from the upper opening35and is discharged from the side openings36to the outside of the machine body2. Therefore, the condenser27and the radiator24are cooled by the outside air. The engine room ER is provided with a front opening37(seeFIG.1) formed above the duct34and in front of the radiator24, and the air warmed in the engine room ER is introduced into the duct34through the front opening37, and is discharged from the side openings36to the outside of the machine body2. In this manner, the temperature in the engine room ER is lowered.

As shown inFIGS.1,2, and5, the fan cover40is provided above the second fan26to cover the upper side of the second fan26(opposite to the condenser27). The fan cover40is attached to the hood9provided at an upper rear portion of the machine body2. The fan cover40is attached to cover a ventilation opening9a(seeFIGS.1and4) formed in the hood9.

As shown inFIG.1, the fan cover40protrudes upward from the upper surface of the hood9. The upper surface of the fan cover40is inclined downwardly rearward. As shown inFIG.5, in plan view, the fan cover40covers the entire second fan26and the substantially entire condenser27. Thus, by removing the fan cover40, the second fan26and the condenser27can be accessed from above for maintenance and the like.

As shown inFIG.6, the fan cover40has ventilation holes40aallowing an air flow therethrough. The ventilation holes40aare joined to the ventilation opening9aformed in the hood9. In the present embodiment, the fan cover40is formed of perforated metal, and perforations in the perforated metal serve as the ventilation holes40a. InFIG.6, the fan cover40is illustrated as being formed in only a portion of the upper surface thereof with ventilation holes40a, but it is preferable that the ventilation holes40aare provided in the entire upper surface of the fan cover40. In the drawings other thanFIG.6, the ventilation holes40aare not shown.

As shown inFIGS.5,6, and7, the fan cover40has a first portion41and second portions42. The fan cover40has an outline formed in a convex shape when viewed from the front, with the first portion41defining an upper portion of the convex shape and the second portion42defining a lower portion of the convex shape. In other words, the first portion41is formed at a position higher than the second portion42. The first portion41is disposed in the vicinity of the center of the fan cover40in the machine-width direction K2. The second portion42includes left and right portions disposed on left and right sides of the first portion41in the machine-width direction K2. The first portion41and the second portion42may be formed integrally in an inseparable state, or the first portion41may be detachable from the second portions42.

The first portion41includes a first upper plate41a, a first front plate41b, a first rear plate41c, a first left plate41d, and a first right plate41e. The first upper plate41ais rectangular in plan view. The first front plate41bextends in the machine-width direction K2along a front edge of the first top plate41a. The first rear plate41cextends in the machine-width direction K2along a rear edge of the first upper plate41a. The first left plate41dextends in the fore-and-aft direction K1along a left edge of the first upper plate41a. The first right plate41eextends in the fore-and-aft direction K1along a right edge of the first upper plate41a. The first front plate41b, the first rear plate41c, the first left plate41d, and the first right plate41ehave their upper edges arranged along an upper surface of the first upper plate41aand their lower edges positioned below the first upper plate41a.

A first upper surface41f, which is an upper surface of the first upper plate41a, includes a first flat surface41gand first uneven surfaces41h. The first flat surface41ghaving a predetermined width is formed at the center of the first upper surface41fin the machine-width direction K2. The first uneven surfaces41hare formed on the left and right sides of the first flat surface41g, respectively. The first uneven surface41hhas first concave portions41iconcaved downward. The first concave portions41idefine grooves extending in the fore-and-aft direction K1. The first front plate41band the first rear plate41chave first openings41jat positions corresponding to the first concave portions41i. In this manner, rainwater and dusts accumulated in the first concave portions41ican be discharged through the first opening41j.

As shown inFIG.5, in plan view, the first upper surface41fcovers the entire second fan26(including the second motor30and the second blade31). In addition, the first flat surface41gis disposed to overlap the second motor30of the second fan26in plan view. In other words, the first upper surface41fis arranged to entirely cover the second fan26from above, and the first flat surface41gis arranged to cover the second motor30from above.

The second portion42includes second upper plates42a, a second front plate42b, a second rear plate42c, a second left plate42d, and a second right plate42e. The second upper plates42aare disposed lower than the first upper plate41a. The second upper plates42ainclude a second upper plate42aL extended leftward from the first upper plate41aand a second upper plate42aR extended rightward from the first upper plate41ain the machine-width direction K2. That is, the second upper plate42aL and the second upper plate42aR are spaced from each other in the machine-width direction K2. Each of the second upper plate42aL and the second upper plate42aR is rectangular in plan view.

The second front plate42bextends in the machine-width direction K2so as to connect a front edge of the second upper plate42aL and a front edge of the second upper plate42aR to each other. The second rear plate42cextends in the machine-width direction K2so as to connect a rear edge of the second upper plate42aL and a rear edge of the second upper plate42aR to each other. The second left plate42dextends in the fore-and-aft direction K1along a left edge of the second upper plate42a. The second right plate42eextends in the fore-and-aft direction K1along a right edge of the second upper plate42a. The second front plate42b, the second rear plate42c, the second left plate42d, and the second left plate42dinclude respective upper edges extended along an upper surface of the second upper plate42aand include respective lower edges disposed below the second upper plates42a.

A second upper surface42f, which is an upper surface of the second upper plate42a, includes a second flat surface42gand second uneven surfaces42h. The second flat surface42ghaving a predetermined width is formed as a left portion of the second upper surface42fof the second upper plate42aL. The second uneven surfaces42hare formed as a right portion of the second upper surface42fof the second upper plate42aL and as the entire second upper surface42fof the second upper plate42aR. Each of the second uneven surfaces42hincludes second concave portions42iconcaved downward. The second concave portions42idefine grooves extending in the fore-and-aft direction K1. The second rear plate42chas second openings42jat positions corresponding to the respective second concave portions42i. In this manner, rainwater and dusts accumulated in the second concave portions42ican be discharged from the second openings42j.

Since the fan cover40has the first concave portions41iand the second concave portions42i, the surface area of the fan cover40is increased so as to improve the heat radiation efficiency. Therefore, the heat in the engine room ER can be efficiently released to the outside. In addition, the strength of the fan cover40can be enhanced by the first concave portions41iand the second concave portions42iprovided in the fan cover40. Accordingly, even when an external force is applied to the fan cover40, the fan cover40is suppressed from being deformed. Moreover, when dusts accumulate on the upper surface of the fan cover40, the dusts tend to accumulate in the lowered first and second concave portions41iand42i, so that the dusts hardly accumulate in higher portions other than the first and second portions41iand42i. Accordingly, the accumulation of dusts over the entire upper surface of the fan cover40is suppressed.

As shown inFIG.2, in the fan cover40, the first space S1formed below the first upper surface41fof the first portion41expands upward compared to the second space S2formed below the second upper surface42fof the second portion42. Accordingly, below the fan cover40, the first space S1serves as a sufficiently wide space that can incorporate the second fan26. In other words, the second fan26can be arranged in the wide first space S1formed below the first upper surface41f.

While the first upper surface41fincluding the first flat surface41gand the first uneven surfaces41his disposed above the second fan26, the first flat surface41gincluding no concave such as the first concave portions41iis disposed above the second motor30, thereby being prevented from interfering with the second motor30.

If the first upper surface41fincluded only the first uneven surface41hwithout the first flat surface41g, the first concave portions41iwould be disposed above the second motor30. In this case, in order to prevent interference between the second motor30and the first concave portions41i, the first upper surface41fneeds to be raised by the depths (that is, heights) of the first concave portions41i; however, if the first upper surface41fwere raised, the first upper surface41fwould hinder the rearward view of an operator sitting on the driver seat8in the cabin3, thereby causing inconvenience. Therefore, in the present embodiment, the first upper surface41fhas the first flat surface41gsuch as to eliminate interference between the second motor30and the first concave portions41i. Accordingly, there is no need to raise the first upper surface41fby the depths of the first concave portions41i, and the height of the first upper surface41fcan be lowered. As the result, the above-mentioned inconvenience of deteriorating the rearward view of the operator does not occur.

As shown inFIG.8, the working machine1is provided with a controller60. The controller60is configured or programmed to perform various controls relating to the working machine1, includes a semiconductor such as a CPU and a MPU, an electric or electronic circuit, or the like, and includes a storage storing various control programs. The controller60includes a main electronic control unit (hereinafter referred to as the “main ECU”) that performs controls relating to traveling and controls relating to work. In addition, an electronic control unit for the engine (referred to as an engine ECU)59is electrically connected to the controller60via a Controller Area Network (referred to as the CAN).

The controller60is configured or programmed to receive signals (that is, detection signals and the like) from a first sensor61, a second sensor62, a rotation speed sensor63, a changeover switch64, a disconnection detector65, and an accelerator66. In addition, the controller60is configured or programmed to transmit control signals to the first fan25and the second fan26.

The first sensor61is an operation fluid temperature sensor configured to detect a temperature of the operation fluid for operating the working device4. The second sensor62is a coolant temperature sensor configured to detect a temperature of the coolant for cooling the engine22. The first sensor61and the second sensor62include respective fault detectors that detect faults in the respective sensors. Each of the fault detectors, when detecting a fault of the corresponding first or second sensor61or62, transmits a detection signal to the controller60.

The rotation speed sensor63is a sensor configured to detect a rotation speed (specifically, an actual rotation speed) of the engine22. The rotation speed (the actual rotation speed) of the engine22detected by the rotation speed sensor63is input (or transmitted) to the controller60.

The changeover switch64is a switch shiftable between an ON-state to permit rotation of the first fan25in the second direction and an OFF-state to forbid the rotation. A switching signal (that is, ON-signal or OFF-signal) of the changeover switch64is input (that is, transmitted) to the controller60. The changeover switch64is manually operable to be switched between the ON-state and the OFF-state, and when it is switched ON, the rotational direction of the first fan25is switched from the first direction to the second direction, and when it is switched OFF, the rotational direction of the first fan25returns to the first direction. The controller60, when receiving the signal from the changeover switch64, performs the switching of rotational direction by switching a later-discussed directional switching valve73.

The disconnection detector65detects disconnection of harnesses that transmit the control signals for controlling driving of the first fan25and the second fan26. When the disconnection detector65detects disconnection of the harness, a detection signal is input (or transmitted) to the controller60.

The accelerator66is provided in the vicinity of the driver seat8. The accelerator66is a setting member for setting a rotation speed of the engine22(that is, an instructed rotation speed). The accelerator66is, for example, an acceleration lever, an accelerator pedal, a acceleration volume, an acceleration slider, or the like. The instructed rotation speed (referred to as a target speed) of the engine22set by the accelerator66is input (or transmitted) to the controller60.

The first fan25is fluidly connected to a control valve70for controlling rotation of the first fan25. The control valve70is controlled by a control signal from the controller60. The control valve70is fluidly connected via a hydraulic circuit to the first motor28for driving the first fan25, and controls a flow of the operation fluid supplied to the first motor28. In the present embodiment, as shown inFIG.8, the control valve70includes an unloading valve71, a proportional valve72, and the directional switching valve73. However, the control valve70need not include the unloading valve71. The control valve70includes a second fault detector for detecting fault of the control valve70.

The unloading valve71is a valve for rotating or stopping the first fan25. When the unloading valve71is closed, operation fluid is supplied to the first motor28for driving the first fan25. When the unloading valve71is opened, the supply of operation fluid to the first motor28is stopped. Accordingly, the first fan25rotates when the unloading valve71is closed, and the first fan25stops when the unloading valve71is opened.

The proportional valve72is a relief valve for changing (that is, increasing or decreasing) a rotation speed of the first fan25when the unloading valve71is closed. The proportional valve72changes an opening degree corresponding to a supplied current value, and the amount of operation fluid supplied to the first motor28increases or decreases according to variation of the opening degree, thereby increasing or decreasing a rotation speed of the first fan25. Specifically, as the current value increases, the opening degree increases, the amount of operation fluid supplied to the first motor28decreases, and the rotation speed of the first fan25decreases. As the current value decreases, the opening degree decreases, the amount of operation fluid supplied to the first motor28increases, and the rotation speed of the first fan25increases. When the proportional valve72is fully open, the rotation speed of the first fan25becomes the minimum speed. When the proportional valve72is fully closed, the rotation speed of the first fan25becomes the maximum speed.

The directional switching valve73is a bidirectional switching valve and configured to switch a flow direction of the operation fluid supplied to the first motor28between one and the other opposite directions. When the operation fluid flows in one direction, the first motor28rotates in one direction, and the first fan25rotates in the first direction. When the operation fluid flows in the other direction, the first motor28rotates in the other direction, and the first fan25rotates in the second direction.

As shown inFIG.8, the second fan26has a rotation controller75configured or programmed to control a rotation of the second fan26. The rotation controller75includes an electric circuit including an inverter and the like. The rotation controller75controls a timing of driving or stopping the second fan26by receiving a control signal from the controller60. The controller60controls the driving of the first fan25and the second fan26.

FIG.9illustrates an example of action patterns of the first fan25, the second fan26, and the directional switching valve73controlled by the controller60, and the horizontal axis represents an axis of time.

As shown inFIG.9, the controller60stops the second fan26while the first fan25rotates in the first direction (that is, in a period Ta) and drives the second fan26while the first fan25is rotating in the second direction (that is, in a period Tβ). The second fan26is driven to rotate in the second direction.

The rotational direction of the first fan25is changed by switching of the directional switching valve73by the controller60. The controller60controls the rotation controller75for controlling driving and stopping of the second fan26.

When the drive of the second fan26is stopped, the rotation of the second motor for driving the second fan26is stopped. At this time, the blades of the second fan26may be completely stationary, or they may rotate following the rotation of the first fan25in the same rotational direction as the first fan25by the airflow generated by the first fan25rotating in the first direction.

As shown inFIG.9, while the first fan25is rotating in the first direction (that is, for the period Ta), the first airflow FL1that introduces the outside air into the inside of the machine body2is generated to cool the radiator24and the condenser27. While the first fan25is rotating in the second direction (that is, for the period Tβ), the second air flow FL2is generated to discharge the air inside the machine body2to the outside of the machine body2. The second airflow FL2can blow away dusts adhering to the radiator24and dusts deposited on the hood9.

However, the first fan25alone rotating in the second direction may not provide sufficient airflow for blowing away the dusts. Especially, ducts existing at a position corresponding to the central portion of the first fan25may be insufficiently blown away because the air capacity of the central portion of the first fan25and its vicinity (that is, a portion close to the rotation shaft) is smaller than the air capacity of the peripheral portion of the first fan25(that is, a portion separating away from the rotation shaft).

For this reason, the controller60drives the second fan26to rotate in the second direction while the first fan25is rotating in the second direction (that is, for the period Tβ), as shown inFIG.9. In this manner, the second fan26also generates the second airflow FL2that discharges the air inside the machine body2to the outside of the machine body2. The air capacity generated by the rotation of the second fan26can compensate for the insufficient air capacity generated by the rotation of the first fan25alone. That is, the rotation of the second fan26increases the air capacity of the second air flow FL2for discharging the air inside the machine body2to the outside of the machine body2. Accordingly, dusts that cannot be blown away by the rotation of the first fan25alone can be blown away.

In addition, when the center axis of the rotation shaft of the first fan25and the center axis of the rotation shaft of the second fan26are arranged coaxially to each other, and the second fan26is diametrically smaller than the first fan25, the outer peripheral portion of the second fan26and its vicinity is positioned to correspond to the vicinity of the central portion of the first fan25. Accordingly, the larger air capacity portion of the second fan26(that is, the outer peripheral portion of the second fan26and its vicinity) is disposed in correspondence to the less air capacity portion of the first fan25(that is, the central portion of the first fan25and its vicinity). Therefore, the dusts that cannot be blown away by the rotation of the first fan25alone can be blown away more reliably.

As described above, the air capacity of the first fan25when rotated in the first direction is larger than the air capacity thereof when rotated in the second direction. In this manner, when the first fan25is rotated in the first direction, the air capacity of the first fan25alone can provide sufficient cooling effect. On the other hand, when the first fan25is rotated in the second direction, the second fan26also rotates in the second direction, so that their air capacity for blowing away dusts is not insufficient. That is, both the cooling effect of the radiator24and the like and the effect of blowing away the dust can be surely obtained.

FIG.10illustrates another example of an action pattern of the first fan25, the second fan26, and the directional switching valve73controlled by the controller60, and the horizontal axis represents an axis of time.

First, an operation control of the first fan25by the controller60will be described.

As shown inFIG.10, the controller60drives the first fan25to repeat a process of actions P1, which includes a speed-increasing action a to increase a second direction rotation speed and a speed-reducing action b to reduce the second direction rotation speed having been increased by the speed-increasing action a, within the predetermined period T1. The repeating the process of actions P1within the predetermined period T1means that the process of actions P1is performed multiple times within the predetermined period T1. In the example shown inFIG.10, the process of actions P1is performed three times within the predetermined period T1, but the number of times of the process of actions P1may be two, four, or more.

The speed-increasing action a and the speed-reducing action b are performed by increasing or decreasing a current value to be supplied to the proportional valve72. The speed-increasing action a is performed by decreasing the current value to be supplied to the proportional valve72to increase an opening degree of the proportional valve72. The speed-reducing action b is performed by increasing the current value to be supplied to the proportional valve72to decrease the opening degree of the proportional valve72. That is, the change in the current value supplied to the proportional valve72is opposite to the change in the rotation speed of the first fan25.

When the current value supplied to the proportional valve72is at its maximum, the first fan25is at its minimum rotation speed. This minimum speed is a low speed close to zero, but may be zero. When the current value supplied to the proportional valve72is at its minimum, the first fan25is at its maximum rotation speed. InFIG.10, a part indicated by a sign c is a part where the rotation speed of the first fan25is at the maximum. A part indicated by a sign d is a part where the rotation speed of the first fan25is the minimum.

As shown in the left part ofFIG.10, the controller60performs a first switching action to switch the rotational direction of the first fan25from the first direction to the second direction before starting the repetition of the process of actions P1. Specifically, the controller60first rotates the first fan25in the first direction at the minimum speed. Then, the controller60performs the first switching action to switch the rotational direction of the first fan25from the first direction to the second direction. The first switching action is performed by switching the directional switching valve73from the OFF state to the ON state. The first switching action is performed when the rotation speed of the first fan25is the minimum speed.

After the first switching action is performed, that is, after the first fan25starts rotating in the second direction at the minimum speed, the first speed-increasing action a of the above process of actions P1is performed, and the process of actions P1including the speed-increasing action a is repeated within the predetermined period T1. The first fan25continues to rotate in the second direction for a predetermined period of time T1after its rotational direction is switched from the first direction to the second direction by the first switching action.

As shown in the right part ofFIG.10, the controller60performs a second switching action to switch the rotational direction of the first fan25from the second direction to the first direction after the repetition of the process of actions P1is ended. The second switching action is performed by switching the directional switching valve73from the ON state to the OFF state. The second switching action is performed when the rotation speed of the first fan25is at the minimum speed after the last speed-reducing action b of the above process of actions P1is performed.

As described above, the first fan25can reliably blow away dusts for a long time by repeating the process of actions P1including the speed-increasing action a and the speed-reducing action b within the predetermined period T1. When the rotation of the first fan25in the second direction is continued for a long period of time at a constant high rotation speed, a negative pressure (that is, a suction pressure) may be generated on the hood from which the wind blows out, thereby making it impossible to blow away the dust. However, as described above, by repeatedly increasing or decreasing the rotation speed during the rotation of the first fan25in the second direction, the negative pressure (that is, the suction pressure) is prevented from being generated on the hood from which the wind blows out. Accordingly, dusts can be blown away reliably for a long time.

As shown inFIG.10, the controller60increases the rotation speed in the second direction to the maximum speed by performing the speed-increasing action a, and decreases the rotation speed in the second direction to the minimum speed by performing the speed-reducing action b. Due to the repetition of actions, the above-mentioned generation of the negative pressure can be further surely prevented, and due to the air capacity increased by the increase in the rotation speed from the minimum rotation speed to the maximum rotation speed, the dusts can be blown away reliably by the power of the air capacity that increases greatly with the increase in the rotation speed.

In the process of actions P1, the controller60controls the drive of the first fan25, so that a time Tc of rotation at the maximum rotation speed is longer than a time Td of rotation at the minimum rotation speed (Tc>Td). In this manner, it is possible to obtain a longer time in which the air capacity of the second airflow FL2blowing away the dusts is large, and accordingly the dust can be blown away more reliably.

Alternatively, in the process of actions P1, the controller60may control the drive of the first fan25, so that the time Td of rotation at the minimum rotation speed is longer than the time Tc of rotation at the maximum rotation speed (Td>Tc). In this case, dusts can be effectively blown away by increasing the air capacity of the first fan25with increase of the rotation speed of the first fan25from the minimum to the maximum.

In the process of actions P1, the controller60may control the drive of the first fan25, so that the time Tc for rotation at the maximum speed becomes the same as the time Td for rotation at the minimum speed (Tc=Td).

Next, control of the action of the second fan26by the controller60will be described.

As shown inFIG.10, the controller60causes the driving of the second fan26to start at the same time as the first switching action for switching the rotational direction of the first fan25from the first direction to the second direction. Then, the controller60continues to drive the second fan26during a period (that is, the predetermined period T1) in which the above process of actions P1is repeated. Accordingly, the predetermined period T1may also be referred to as a period during which the second fan26is continuously driven. During the predetermined period T1, the second fan26is continuously driven to rotate in the second direction. Moreover, the controller60stops the driving of the second fan26at the same time as the second switching action for switching the rotational direction of the first fan25from the second direction to the first direction.

In this manner, during the predetermined period T1, even when the air capacity of the first fan25rotating in the second direction is insufficient, this air capacity insufficiency can be compensated by the air capacity of the second fan26due to the continuous driving the second fan26during the predetermined period T1in which the process of actions P1is repeated. For example, when the first fan25is rotated in the second direction at the minimum speed, the air capacity of the first fan25insufficient to blow away dusts can be compensated for by the air capacity of the second fan26rotating in the second direction. Accordingly, during the predetermined period T1for which the process of actions P1is repeated, the air capacity sufficient for blowing away dusts can be continuously obtained.

In the present example shown inFIG.10, the driving of the second fan26is started simultaneously with the first switching action. Alternatively, the driving of the second fan26may be started at a different time from the time for the first switching action. Specifically, the driving of the second fan26may be started before the first switching action. In this case, the second airflow FL2can be generated by the second fan26prior to the first fan25, so that dusts can be blown away quickly. Alternatively, the driving of the second fan26may be started after the first switching action.

In the present example, the driving of the second fan26is stopped simultaneously with the second switching action. Alternatively, the driving of the second fan26may be stopped at a different time from the time for the second switching action. Specifically, the driving of the second fan26may be stopped after the second switching action. In this case, the second fan26is still driven continuously for a while (that is, a predetermined time) after the second switching action, and then is stopped. Therefore, even if dusts blown away and flown in the air fall down, the ducts are blown away, thereby being kept from being deposited on the hood9again. Alternatively, the driving of the second fan26may be stopped before the second switching action.

In the example shown inFIG.10, the rotation speed of the second fan26rotating in the second direction is constant during the predetermined period T1. Alternatively, the rotation speed of the second fan26rotating in the second direction may be increased or decreased. When increasing or decreasing the rotation speed of the second fan26rotating in the second direction, it is preferable to set the second fan26to be rotated at a high rotation speed when the first fan25is rotated at a low rotation speed, and to set the second fan26to be rotated at a low rotation speed when the first fan25is rotated at a high rotation speed. Therefore, the magnitude of the second airflow FL2is kept constant during the predetermined period T1.

FIG.11illustrates another example of an action pattern of the first fan25, the second fan26, and the directional switching valve73controlled by the controller60, and the horizontal axis represents an axis of time.

As shown inFIG.11, the controller60is configured to cause the first fan25to perform a basic action (see solid lines) that starts the rotation in the second direction and ends it after passage of a predetermined time T2, and a canceling action (see dashed lines) that stops or interrupts the rotation of the first fan25in the second direction when an interruption condition is satisfied within the predetermined time T2.

First, control of the actions of the first fan25by the controller60will be described.

The basic action of the first fan25commanded by the controller60includes at least the action of starting the rotation in the second direction and the action of terminating the rotation after the elapse of a predetermined time from the starting. In addition to the action shown in the solid lines inFIG.11, the basic action may include the action performed during the predetermined period T1shown inFIG.10(that is, repetition of the process of actions P1including the speed-increasing action a and the speed-reducing action b within the predetermined period T1), or may include any other action.

The following explanation is based on the case where the basic action is the action represented by the solid lines inFIG.11. In this basic action, first, the first fan25is driven to rotate in the first direction at the minimum rotation speed. Next, the rotational direction of the first fan25is changed from the first direction to the second direction by switching the directional switching valve73when the first fan25is rotating at the minimum speed. Then, the speed-increasing action a is performed to increase a rotation speed of the first fan25in the second direction to the maximum rotation speed. And then, after continuing the rotation in the second direction at this maximum rotation speed, the speed-reducing action b is performed to decrease the rotation speed in the second direction. After the rotation speed of the first fan25in the second direction becomes the minimum speed, the rotational direction of the first fan25is changed from the second direction to the first direction by switching the directional switching valve73, and the rotation in the second direction is terminated.

In this basic action, a time from a timing t-1when the rotational direction of the first fan25is changed from the first direction to the second direction to a timing t-2when the rotational direction of the first fan25is changed from the second direction to the first direction is defined as a predetermined time T2.

The controller60causes the canceling action to be executed to cancel the rotation of the first fan25in the second direction when the interruption condition is satisfied within the predetermined time T2. The canceling action is executed by transmitting a cancellation signal from the controller60to the control valve70to control the first fan25. InFIG.11, a cancellation signal is transmitted from the controller60at a timing t-3. The interruption condition will be described later.

The canceling action may be an operation to switch the rotational direction to the first direction after gradually decreasing the rotation speed of the first fan25in the second direction (hereinafter referred to as the “first canceling action”), or an operation to decrease the rotation speed of the first fan25in the second direction to the minimum rotation speed and then stop the rotation after a predetermined time has elapsed after (hereinafter referred to as the “second canceling action”). That is, there are two cases of “stopping the rotation of the first fan25in the second direction” to be executed by the canceling action: “a case where the rotational direction of the first fan25is switched from the second direction to the first direction” by the first canceling action and “a case where the rotation of the first fan25is stopped (the rotation speed becomes 0)” by the second canceling action.

Referring toFIG.11, the first canceling action and the second canceling action will be described.

First, the case where the controller60causes the first fan25to perform the first canceling action will be described. In this case, when the controller60sends a cancellation signal to the control valve70at the timing t-3, a rotation speed of the first fan25in the second direction gradually decreases (see a part of an arrowed line e inFIG.11). In detail, when the controller60sends the cancellation signal to the control valve70at the timing t-3, the current value to be supplied to the proportional valve72gradually increases and the opening degree of the proportional valve72gradually increases. In this manner, an amount of operation fluid to be supplied to the hydraulic motor for driving the first fan25gradually decreases, and thus a rotation speed of the first fan25in the second direction gradually decreases. After the rotation speed of the first fan25in the second direction becomes the minimum rotation speed, the directional switching valve73is switched from the ON state to the OFF state (see a part of an arrowed line g), and the rotational direction of the first fan25is changed from the second direction to the first direction. After that, the controller60continues the rotation of the first fan25in the first direction and increases the rotation speed of the first fan25in the first direction as needed (see a part of an arrowed line f1).

Next, a case where the controller60causes the first fan25to perform the second canceling action will be explained. In this case, when the controller60sends a cancellation signal to the control valve70at the timing T-3, the rotation speed of the first fan25in the second direction gradually decreases by the same action as that in the case of the first canceling action mentioned above (see the part of the arrowed line e inFIG.11). The rotation speed of the first fan25in the second direction becomes the minimum rotation speed, and then the rotation of the first fan25in the second direction is stopped after a predetermined time T3has elapsed (see a part of an arrowed line f2inFIG.11). In this case, the directional switching valve73is not switched from the ON state to the OFF state (the part of the arrowed line g), and the first fan25stops rotating by decreasing the rotation speed in the second direction. The rotation of the first fan25in the second direction can be stopped by opening the unloading valve71. When opening the unloading valve71, the supply of operation fluid to the hydraulic motor for driving the first fan25is stopped, thereby stopping the rotation of the first fan25in the second direction.

Next, control of the action of the second fan26by the controller60will be described.

As shown inFIG.11, the controller60starts to drive the second fan26when the first fan25starts to rotate in the second direction. In addition, the controller60stops the driving of the second fan26when the first fan25terminates the rotation in the second direction. The second fan26continuously rotates in the second direction for the predetermined time T2since the first fan25starts to rotate in the second direction until the first fan25terminates the rotation.

While the controller60controls the first fan25to execute the basic action, a driving pattern of the second fan26is a pattern shown by the solid lines inFIG.11. In this case, after the rotation speed of the first fan25in the second direction becomes the minimum rotation speed, the second fan26stops driving at the same time as or after the switching of the directional switching valve73.

When the controller60controls the first fan25to execute the canceling action, the driving pattern of the second fan26is a pattern shown by the virtual lines inFIG.11. When the first canceling action is executed, the second fan26stops driving after the rotation speed of the first fan25in the second direction gradually decreases and becomes the minimum rotation speed.

An example of the interruption condition for execution of the above-described canceling action will be described below.

A first example of the interruption condition is that a temperature detected by the first sensor61or the second sensor62is out of a predetermined temperature range. The condition of “being out of a predetermined temperature range” means that the temperature exceeds the upper limit temperature in a predetermined temperature range or falls below the lower limit temperature in the predetermined temperature range. When the temperature detected by the first sensor61or the second sensor62is out of the predetermined temperature range, the controller60determines that the interruption condition has been satisfied and causes the first fan25to perform the canceling action. When the temperature detected by the first sensor61or the second sensor62is out of the predetermined temperature range, the controller60causes the first fan25to execute either the first canceling action or the second canceling action. Some cases can be predetermined as the interruption condition for determination of whether the first canceling action or the second canceling action should be executed. The cases predetermined as the interruption condition include a case where the temperature detected by the first sensor61exceeds the upper limit temperature of the predetermined temperature range, a case where the temperature detected by the first sensor61falls below the lower limit temperature of the predetermined temperature range, a case where the temperature detected by the second sensor62exceeds the upper limit temperature of the predetermined temperature range, and a case where the temperature detected by the second sensor62exceeds the upper limit temperature of the predetermined temperature range.

For example, when the temperature detected by the first sensor61or the second sensor62exceeds the upper limit temperature of the predetermined temperature range, the first canceling action changes the rotational direction of the first fan25from the second direction to the first direction, and thus the first fan25generates the first airflow FL1for introducing the outside air into the machine body2. As the result, the temperature of the operation fluid that activates the working device4or the temperature of the coolant that cools the engine22can be lowered, thereby preventing various devices in the working machine1from being overheated or suffering another problem.

For example, when the temperature detected by the first sensor61falls below the lower limit of the predetermined temperature range, the rotation of the first fan25can be stopped by the second canceling action to prevent an abnormal pressure rising and the like from occurring in the hydraulic circuit, and to prevent a surge pressure occurring in the hydraulic circuit from exceeding a specified pressure.

A second example of an interruption condition is that the engine22stops. In this case, the controller60determines that the interruption condition is satisfied when the engine22stops and controls the first fan25to perform the canceling action. When the engine22stops due to engine stalling or the like, the rotation of the first fan25is stopped by the second canceling action. In this case, the controller60decreases the rotation speed of the first fan25to the minimum speed and then stops the rotation of the first fan25.

A third example of an interruption condition is that the switch64is switched to the OFF state. In this case, the controller60determines that the interruption condition is satisfied when the switch64is switched to the OFF state and controls the first fan25to perform the canceling action. In this manner, the rotation of the first fan25in the second direction can be interrupted by switching the switch64to the OFF state when some abnormality occurs in the working machine1or the like.

The canceling action according to this third example is performed, for example, when a person approaches the vicinity of the working machine1while the first fan25is rotated in the second direction. When the first fan25is rotated in the second direction, dusts on the hood9may be blown away and scattered toward the approaching person, but by switching the switch64to the OFF state and canceling the rotation of the first fan25in the second direction, the dusts can be prevented from being scattered toward the person.

The canceling action according to the third example can also be performed when the working machine1performs a heavy work requiring high horsepower by the working device4. By switching the switch64to the OFF state and stopping the rotation of the first fan25when the working machine1performs the heavy work, it becomes easier to perform the heavy work with the working device4.

A fourth example of an interruption condition is that a fault of a component related to the driving of the first fan25or the second fan26is detected by a detector. The detector is, for example, the disconnection detector65that detects a disconnection of a harness or a second fault detector that detects a fault of a control valve70, but not limited thereto. One example as the fourth example is that a disconnection is detected by the disconnection detector65. In this case, the controller60determines that the interruption condition is satisfied when the disconnection is detected by the disconnection detector, and controls the first fan25to execute the canceling action. This canceling action stops the rotation of the first fan25, thereby preventing abnormal rotation of the first fan25caused by the disconnection. Another example of the fourth example is that the second fault detector detects a fault of the control valve70(such as a fault of a solenoid) that controls the rotation of the first fan25. In this case, the controller60determines that the interruption condition is satisfied when the second fault detector detects the fault of the control valve70and controls the first fan25to perform the canceling action. This canceling action stops the rotation of the first fan25, thereby preventing abnormal rotation of the first fan25caused by the fault of the control valve70.

A fifth example of the interruption condition is that the filter regenerator that regenerates the filter of the exhaust gas purification device23is performing a filter regeneration process that burns particulate matters. In this case, the controller60determines that the interruption condition is satisfied when the filter regeneration processing unit is performing the filter regeneration process to burn particulate matters, and controls the first fan25to perform the canceling action. This canceling action can prevent the high-temperature air from being discharged to the outside of the machine body2by changing the rotational direction of the first fan25from the second direction to the first direction. In addition, since the first fan25generates the first airflow FL1that introduces the outside air into the inside of the machine body2, the temperature inside the machine body2can be lowered.

A sixth example of the interruption condition is that a difference value (that is, a dropping rotation speed) obtained by subtracting an actual rotation speed, which is a rotation speed detected by the rotation speed sensor63, from a target rotation speed, which is a rotation speed set by the accelerator (that is, a setting member)66, exceeds a predetermined threshold. In this case, the controller60determines that the interruption condition is satisfied when the dropping rotation speed becomes equal to or higher than the threshold value (that is, when a large engine dropping occurs) and controls the first fan25to perform the canceling action. This canceling action stops the rotation of the first fan25, thereby preventing the engine stalling.

A seventh example of the interruption condition is that either one of the respective fault detectors provided in the first sensor61and the second sensor62detects a fault of the first sensor61or the second sensor62. In this case, the controller60determines that the interruption condition is satisfied when the fault detector detects a fault of the corresponding sensor and controls the first fan25to perform the canceling action. By changing the rotational direction of the first fan25from the second direction to the first direction or by interrupting the rotation of the first fan25, it is possible to prevent the fault of the first sensor61or the second sensor62from excessively increasing a temperature of the operation fluid or coolant or from causing the abnormal pressure rising in the hydraulic circuit.

An eighth example of the interruption condition is that the air conditioner is driven. In this case, the controller60determines that the interruption condition is satisfied when the air conditioner is driven, and controls the first fan25to perform the canceling action. By stopping the rotation of the first fan25by the canceling action, it becomes easier to perform a work when the working machine1performs a heavy work, for example.

The above-described interruption conditions are examples, and the interruption conditions are not limited to the above-described conditions. For example, it may be configured to execute the canceling action under a condition, as the interruption condition, where the temperature detected by an outside temperature sensor is out of the predetermined temperature range. The above-mentioned combination of each interruption condition and the canceling action associated with the satisfying of the interruption condition is also an example, and other combinations (for example, for some of the above-mentioned interruption conditions, the second canceling action is executed instead of the first canceling action, the first canceling action is executed instead of the second canceling action, or the like) may be adopted as necessary.

The control method described above based onFIGS.10and11is suitably used when the first fan25is a fan arranged on one directional surface side (that is, the lower surface side) of the radiator24and the second fan26is a fan arranged on the other directional surface side (that is, the upper surface side) of the radiator24(seeFIGS.1and3), but the first fan25may be a fan arranged on the above-mentioned other directional surface side (that is, the upper surface side) of the radiator24, and the second fan26may be a fan arranged on the above-mentioned one directional surface side (that is, the lower surface side) of the radiator24.

For example, in the control method described based onFIG.10, the controller60can cause one or both of (at least one of) the fan arranged on one directional surface side (that is, the lower surface side) of the radiator24and the fan arranged on the other directional surface side (that is, the upper surface side) of the radiator24to perform the above process of actions P1. During the predetermined period T1in which the process of actions P1is repeated for either one of the fans, it is also possible to continuously control the driving (that is, the rotation in the second direction) of the other fan.

The control method described based onFIG.10andFIG.11is suitably used in a case where the first fan25is a hydraulic fan and the second fan26is an electric fan, but the first fan25may be an electric fan and the second fan26may be a hydraulic fan. In addition, both the first fan25and the second fan26may be hydraulic or electric fans.

In the above embodiment, one directional surface side of the radiator24is referred to as the lower surface side and the other directional surface side of the radiator24is referred to as the upper surface side, but it may be read that one directional surface side of the radiator24is the upper surface side and the other directional surface side of the radiator24is the lower surface side.

The working machine1includes the machine body2, the engine22provided on the machine body2, the radiator24to cool a coolant supplied to the engine22, the first fan25provided on one directional surface side of the radiator24, the first fan25being rotatable in either one of the first direction to suck external air to an interior of the machine body2and the second direction to generate an air flow for discharging air from the interior of the machine body2to an exterior of the machine body2, and the second fan26provided on the other directional surface side of the radiator24and configured to be rotated in the second direction.

According to this configuration, the air capacity of the second fan26rotating in the second direction can compensate for the insufficient air capacity of only the first fan25rotating in the second direction (for example, the air capacity that is insufficient in the vicinity of the center (near the rotation shaft) of the first fan25), so that the air capacity sufficient for blowing dusts toward the outside of the machine body2can be obtained.

The working machine1includes the controller60to control drive of the first fan25and the second fan26. The controller60is configured or programmed to stop the second fan26when the first fan25rotates in the first direction, and to drive the second fan26when the first fan25rotates in the second direction.

According to this configuration, when the drive of the second fan26is stopped while the first fan25is rotating in the first direction, the second fan26does not obstruct the airflow generated by the rotation of the first fan25in the first direction. In addition, when the second fan26is driven while the first fan25is rotating in the second direction, the second fan26can compensate for the insufficient air capacity of only the first fan25rotating in the second direction.

The working machine1includes the condenser27to condense a refrigerant for the air conditioner provided on the machine body2. The condenser27is provided between the radiator24and the second fan26.

According to this configuration, the radiator24and the condenser27can be cooled by the airflow generated by the rotation of the first fan25in the first direction. In addition, the airflow generated by the rotation of the first fan25and the second fan26in the second direction can blow away dusts adhering to the radiator24and the condenser27.

The air capacity of the first fan25rotating in the first direction is larger than that of the first fan25rotating in the second direction.

According to this configuration, when the first fan25is rotated in the first direction, the air capacity of the first fan25alone can sufficiently provide a cooling effect. When the first fan25is rotated in the second direction, the second fan26also rotates in the second direction, so that the air capacity for blowing away dusts does not become insufficient. Accordingly, both the cooling effect of the radiator24and the like and the effect of blowing away the dusts can be obtained reliably.

The first fan25and the second fan26have respective rotary axes coaxial to each other.

According to this configuration, when the first fan25and the second fan26are rotated in the second direction, the airflow generated by the rotation of the first fan25and the airflow generated by the rotation of the second fan26are joined together, so that sufficient airflow can be obtained to blow away the dusts.

The second fan26is diametrically smaller than the first fan25.

According to this configuration, a larger air capacity portion of the second fan26(i.e., the outer peripheral portion of the second fan26and its vicinity) can be disposed in correspondence to a smaller air capacity of the first fan25(i.e., the central portion of the first fan25and its vicinity), so that dusts that cannot be blown away only by rotation of the first fan25can be surely blown away due to the rotation of the second fan.

The first fan25is a hydraulic fan driven by hydraulic pressure. The second fan26is an electric fan driven by electricity.

According to this configuration, the first fan25, which is driven for cooling over a long period of time, employs a hydraulic fan, and the second fan26, which is driven only when blowing away dusts, employs an electric fan. In this manner, the capacity of a battery mounted on the working machine1can be reduced.

The working machine1includes the fan cover40to cover an upper side of the second fan26opposite to the condenser27. The second fan26is provided on a lower side thereof with the blade (the second blade31), and on an upper side thereof with the motor (the second motor30) for rotating the blade. An upper surface of the fan cover40includes the flat surface (the first flat surface41g) and the uneven surface (the first uneven surface41h). The flat surface (the first flat surface41g) overlaps the motor (the second motor30) in plan view.

According to this configuration, the fan cover40has an uneven surface (the first uneven surface41h), which increases the surface area of the fan cover40to improve the heat radiation effect, improves the strength of the fan cover40, and also prevents dusts from depositing over the entire upper surface of the fan cover40. In addition, since the flat surface (the first flat surface41g) is arranged at a position where the flat surface overlaps the motor (the second motor30) in plan view, interference between the second motor30and the fan cover40can be prevented, and the height of the upper surface of the fan cover40can be lowered compared to the case where the first uneven surface41his arranged above the second motor30. Accordingly, a rear view of the operator can be prevented from being blocked by the fan cover40.

The working machine1includes the machine body2, the engine22provided on the machine body2, the radiator24to cool a coolant supplied to the engine22, the first fan25provided on one directional surface side of the radiator24, the first fan25being rotatable in either one of the first direction to suck external air to an interior of the machine body2and the second direction to generate an air flow for discharging air from the interior of the machine body2to an exterior of the machine body2, and the controller60to control drive of the first fan25. The controller60is configured or programmed to control drive of the first fan25rotating in the second direction in such a way that a process of actions including the speed-increasing action to increase a rotation speed of the first fan25and the speed-reducing action to reduce the rotation speed of the first fan25increased by the speed-increasing action is repeated in a predetermined period.

According to this configuration, by repeating the increase and decrease of the rotation speed when the first fan25is rotating in the second direction, a negative pressure (the suction pressure) is prevented from being generated in a part (on the hood) from which the wind blows out by rotation of the first fan25in the second direction. Accordingly, dusts can be blown away reliably for a long time.

The controller60is configured or programmed to increase the rotation speed of the first fan25rotating in the second direction to the maximum rotation speed during the speed-increasing action, and to reduce the rotation speed of the first fan25rotating in the second direction to the minimum rotation speed during the speed-reducing action.

According to this configuration, generation of the negative pressure described above can be prevented more reliably, and the dusts can be blown away reliably by the power of the air capacity that increases greatly in accordance with the increase of the rotation speed from the minimum rotation speed to the maximum rotation speed.

The controller60is configured or programmed to control drive of the first fan25rotating in the second direction during the process of actions P1in such a way that the time Tc for the rotation of the first fan25at the maximum rotation speed is longer than the time Td for the rotation of the first fan25at the minimum rotation speed (Tc>Td).

According to this configuration, the time Tc during which the first fan25rotates at the maximum rotation speed in the second direction becomes longer, so that a longer time can be obtained during which the air capacity of the airflow in the direction of blowing away the dusts is large, and the dusts can be blown away more reliably.

The working machine1includes the second fan26provided on the other directional surface side of the radiator24and configured to be rotated in the second direction. The controller60is configured or programed to drive the second fan26continuously during the predetermined period T1of repeating the process of actions P1.

According to this configuration, the second fan26is continuously driven during the predetermined period T1in which the process of actions P1is repeated, thereby ensuring enough airflow for blowing dusts continuously during the predetermined period T1(even when the first fan25is rotating at the minimum speed).

The controller60is configured or programed to perform the first switching action to switch the rotation direction of the first fan25from the first direction to the second direction before start of repeating the process of actions P1, and to perform the second switching action to switch the rotation direction of the first fan25from the second direction to the first direction after end of repeating the process of actions P1.

According to this configuration, since the first fan25can be rotated in the first direction before and after the repetition of the process of actions P1, the cooling effect of the radiator24and the like can be surely obtained.

The controller60is configured or programed to perform the first switching action and the second switching action when the first fan25rotates at the minimum rotation speed.

According to this configuration, the switching of the rotational direction of the first fan25from the first direction to the second direction and the switching from the second direction to the first direction can be smoothly performed.

The controller60is configured or programed to start drive of the second fan26at the same time as the first switching action.

According to this configuration, since the second fan26starts rotating in the second direction at the same time as the first fan25is switched to the second direction, an air capacity sufficient for blowing dusts can be obtained quickly.

The controller60is configured or programed to stop drive of the second fan26at the same time as the second switching action.

According to this configuration, since the second fan26stops rotating in the second direction at the same time as the first fan25is switched to the first direction, the effect of the airflow (the cooling effect) produced by the rotation of the first fan25in the first direction can be prevented from being reduced by the airflow generated by the rotation of the second fan26.

The controller60is configured or programed to stop drive of the second fan26after performing the second switching action.

According to this configuration, instead of stopping the second fan26at the same time as the second switching action, the second fan26is driven for a while after the second switching action and then stopped, thereby preventing the blown dusts from falling and being deposited on the hood or the like again.

The working machine1includes the machine body2, the engine22provided on the machine body2, the radiator24to cool a coolant supplied to the engine22, the fan (the first fan)25provided on one directional surface side of the radiator24, the first fan25being rotatable in either one of the first direction to suck external air to an interior of the machine body2and the second direction to generate an air flow for discharging air from the interior of the machine body2to an exterior of the machine body2, and the controller60to control drive of the fan25. The controller60is configured or programmed to make the fan25selectively perform either the basic action to finish the rotation of the fan in the second direction after the predetermined period T2elapses from start of the rotation of the fan25in the second direction or the canceling action to interrupt the rotation of the fan25in the second direction when the interruption condition is satisfied in the predetermined period T2.

According to this configuration, while the fan25for cooling the radiator24or the like is being rotated in the reverse direction (the second direction) from the direction in the cooling, the rotation in the reverse direction can be interrupted as needed. In detail, when the interruption condition, under which the rotation in the reverse direction should be stopped, is satisfied during the execution of the basic action in which the fan25is rotating in the reverse direction, the rotation in the reverse direction can be stopped. This can avoid problems (such as overheating of the equipment) that may occur due to continuation of rotation of the fan25in the reverse direction.

The controller60is configured or programed to make the fan25perform the canceling action in such a way that the rotation direction of the fan25is switched to the first direction after the rotation speed of the fan25rotating in the second direction is gradually reduced.

According to this configuration, by gradually reducing the rotation speed of the rotation in the second direction, noise and increase in the surge pressure generated in the hydraulic circuit for supplying the operation fluid to the first fan25can be prevented. In addition, a cooling effect can be obtained by the rotation of the fan25in the first direction after the canceling action.

The controller60is configured or programed to make the fan25perform the canceling action in such a way that the rotation of the fan25is stopped after the rotation speed of the fan25rotating in the second direction is gradually reduced.

According to this configuration, by gradually reducing the rotation speed of the rotation in the second direction, noise and increase in the surge pressure generated in the hydraulic circuit for supplying the operation fluid to the first fan25can be prevented. In addition, by stopping the fan25after the canceling action, abnormal rotation of the fan25and the like can be prevented.

The controller60is configured or programed to make the fan25perform the canceling action in such a way that the rotation of the fan25is stopped after the predetermined period T3elapses since the reduced rotation speed of the fan25rotating in the second direction becomes the minimum rotation speed.

According to this configuration, the fan25can be safely stopped when, for example, engine stoppage as an interruption condition occurs.

The working machine1further includes the working device4attached to the machine body2, the first sensor61to detect a temperature of operation fluid for driving the working device4, and the second sensor62to detect a temperature of the coolant for cooling the engine22. The controller60is configured or programed to define a state where the temperature detected by the first sensor61or the second sensor62deviates from a predetermined temperature range as the satisfied interruption condition for determination to perform the canceling action.

According to this configuration, overheating and the like of equipment mounted on the working machine1can be prevented. In addition, the configuration can prevent abnormal pressure rising and the like occurring in the hydraulic circuit, and can prevent a surge pressure occurring in the hydraulic circuit from exceeding a specified pressure or the like.

The controller60is configured or programmed to define stopping of the engine22as the satisfied interruption condition for determination to perform the canceling action.

According to this configuration, when the engine22is stopped, the rotation of the fan25can be stopped by the canceling action.

The working machine1includes the switch64manually operable to be shifted between the ON state to allow the fan25to rotate in the second direction and the OFF state to hinder the fan25from rotating in the second direction. The controller60is configured or programmed to define the setting of the switch64in the OFF state as the satisfied interruption condition for determination to perform the canceling action.

According to this configuration, when a person approaches the vicinity of the working machine1while the fan25is being rotated in the second direction, the switch64is switched to the OFF state and the canceling action is executed, thereby preventing dusts from being scattered toward the person. In addition, in a case where the working machine1performs heavy work with the work device4, the switching of the changeover switch64to the OFF state and executing of the canceling operation make it easier to perform heavy work with the work device4.

The working machine1includes the detector (the disconnection detector65, the second fault detector, and the like) to detect a fault of a component relevant to the drive of the fan25. The controller60is configured or programmed to define a state where a fault is detected by the detector as the satisfied interruption condition for determination to perform the canceling action.

According to this configuration, abnormal rotation of the fan25caused by a fault of the component can be prevented by executing the canceling action and stopping the rotation of the fan25when the fault of the component related to the driving of the fan25is detected by the detector.

The working machine1includes the exhaust gas purificator23including the filter to trap particulate matters included in exhaust gas from the engine22, and the filter regenerator to burn the particulate matters trapped by the filter. The controller60is configured or programed to define a state where the filter regenerator performs the filter regeneration process to burn the particulate matters as the satisfied interruption condition for determination to perform the canceling action.

According to this configuration, the execution of the canceling action can prevent high-temperature air from being discharged to the outside of the machine body2by changing the rotational direction of the fan25from the second direction to the first direction. In addition, the temperature inside the machine body2can be lowered because an airflow that introduces the outside air is generated inside the machine body2.

The working machine1includes the setting member (the accelerator66) to set a rotation speed of the engine22, and the rotation speed sensor63to detect the rotation speed of the engine22. The controller60is configured or programed to define a state where a differential value obtained by subtracting an actual rotation speed detected by the rotation speed sensor63from an instructed rotation speed set by the setting member (the accelerator66) as the satisfied interruption condition for determination to perform the canceling action.

According to this configuration, when executing the canceling action, the engine stalling can be prevented by stopping the rotation of the fan25.

The working machine includes the working device4attached to the machine body2, the first sensor61to detect a temperature of operation fluid for driving the working device4, the second sensor62to detect a temperature of the coolant for cooling the engine22, and the fault detector to detect a fault of the first sensor61or the second sensor62. The controller60is configured or programed to define a state where a fault is detected by the fault detector as the satisfied interruption condition for determination to perform the canceling action.

According to this configuration, by executing the canceling action, the rotational direction of the fan25is changed from the second direction to the first direction, or the rotation of the fan25is stopped, so that temperature of the operation fluid or coolant can be prevented from rising excessively due to a fault of the first sensor61or the second sensor62, and an abnormal pressure rising can be prevented from occurring in the hydraulic circuit due to a fault of the first sensor61or the second sensor62.

The working machine1includes the cabin3mounted on the machine body2, and the air conditioner to feed a temperature-adjusted air into the cabin3. The controller60is configured or programed to define a state where the air conditioner is driven as the satisfied interruption condition for determination to perform the canceling action.

According to this configuration, by stopping the rotation of the fan25by executing the canceling action, it becomes easier to perform work when the working machine1performs a heavy work, for example.

In the above description, the embodiment of the present invention has been explained. However, all the features of the embodiment disclosed in this application should be considered just as examples, and the embodiment does not restrict the present invention accordingly. A scope of the present invention is shown not in the above-described embodiment but in claims, and is intended to include all modifications within and equivalent to a scope of the claims.