Work equipment

Abstract

A work machine (1) comprises: an electric motor (9); a work device that is driven using power from the electric motor (9); an operation device (5) that operates the work device; an operation lock device (5c) capable of switching between a permission position at which the operation of the work device by the operation device (5) is permitted and a prohibition position at which the operation is prohibited; a cooler (35, 37) having an electric cooling fan (35a, 37a); a temperature detection device (46, 47) that detects a cooled object temperature (T) that is the temperature of an object to be cooled by the cooler (35, 37); and a control device (7) that controls a fan rotation speed (FS) that is the rotation speed of the cooling fan (35a, 37a) in accordance with the cooled object temperature (T) detected by the temperature detection device (46, 47). The control device (7) changes the characteristics of the fan rotation speed (FS) with respect to the cooled object temperature (T), depending on whether the operation lock device (5c) is in the permission position or the prohibition position.

Description

[Technical Field]

[0001] The present invention relates to a work machine such as an excavation machine (backhoe). [Background technology]

[0002] For example, a work machine such as a rotary excavator (backhoe) disclosed in Patent Document 1 is equipped with a radiator having an electric radiator fan for cooling the cooling water that cools the electric motor, etc., and an oil cooler having an electric oil cooler fan for cooling the hydraulic oil. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-80709 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the technique of Patent Document 1 does not take into consideration a specific method for controlling the radiator fan and the oil cooler fan.

[0005] The present invention has been made to solve the problems of the prior art described above, and aims to reduce noise, reduce power consumption, and prevent overcooling in a work machine equipped with an electric fan. [Means for solving the problem]

[0006] A working machine according to one aspect of the present invention includes an electric motor, a working device driven by power of the electric motor, an operating device for operating the working device, and a control device for controlling the operating device. Deviceand a prohibition position that prohibits operation of the working device from the operating position; a cooler having an electric cooling fan; a temperature detection device that detects a cooling object temperature that is the temperature of the cooling object cooled by the cooler; and a control device that controls a fan rotation speed that is the rotation speed of the cooling fan in accordance with the cooling object temperature detected by the temperature detection device, and the control device changes the characteristics of the fan rotation speed relative to the cooling object temperature depending on whether the operation lock device is in the permission position or the prohibition position.

[0007] According to one aspect of the present invention The work equipment is an electric motor; a working device driven by power from the electric motor; an operating device for operating the working device; an operation locking device switchable between an enabling position that enables operation of the working device by the operating device and a disabling position that disables operation of the working device by the operating position; a cooler having an electric cooling fan; a temperature detecting device that detects a cooling object temperature that is the temperature of an object cooled by the cooler; and a control device that controls a fan rotation speed that is the rotation speed of the cooling fan in accordance with the cooling object temperature detected by the temperature detecting device. a storage device that stores a plurality of fan control maps that indicate the characteristics of the fan rotation speed with respect to the temperature of the object to be cooled; and, Equipped with the control device changes a characteristic of the fan rotation speed relative to the temperature of the object to be cooled depending on whether the operation locking device is in the permitted position or the prohibited position, The plurality of fan control maps include a first map and a second map that are different from each other, and the control device controls the rotational drive of the cooling fan based on the first map when the operation locking device is in the prohibition position, and controls the rotational drive of the cooling fan based on the second map when the operation locking device is in the permission position. do .

[0008] The first map may be configured to switch the fan rotation speed between 0 and a predetermined first fan rotation speed depending on the temperature of the object to be cooled.

[0009] The first map may be configured to switch the fan rotation speed to the first fan rotation speed when the value of the temperature to be cooled rises from a value less than a predetermined first rotation rise temperature to the first rotation rise temperature while the fan rotation speed is 0, and to switch the fan rotation speed to 0 when the value of the temperature to be cooled falls to a predetermined first rotation fall temperature lower than the first rotation rise temperature while the fan rotation speed is at the first fan rotation speed.

[0010] The second map may be configured to set the fan rotation speed to a value greater than 0 when the value of the cooling object temperature rises from a value less than a predetermined second rotation rise temperature to the second rotation rise temperature while the fan rotation speed is 0, to set the fan rotation speed to a predetermined second fan rotation speed when the value of the cooling object temperature is equal to or greater than a first specified temperature that is set to a temperature higher than the second rotation rise temperature, to set the fan rotation speed higher as the cooling object temperature is higher within a range less than the second fan rotation speed when the value of the cooling object temperature is equal to or greater than the second rotation rise temperature and less than the first specified temperature, and to reduce the fan rotation speed to 0 when the value of the cooling object temperature falls to a predetermined second rotation drop temperature lower than the second rotation rise temperature while the fan rotation speed is not 0.

[0011] The second map may be configured to set the fan rotation speed to a constant value lower than the second fan rotation speed when the value of the cooling object temperature is equal to or higher than the second rotation start temperature and lower than a second specified temperature that is set to a value lower than the first specified temperature, and to set the fan rotation speed higher as the cooling object temperature is higher within a range lower than the second fan rotation speed when the value of the cooling object temperature is equal to or higher than the second specified temperature and lower than the first specified temperature.

[0012] The plurality of fan control maps include a third map, and when the operation lock device is in the permit position and the operation device is not operated for a predetermined time, the control device sets the rotation speed of the electric motor to an idle rotation speed and controls the cooling fan based on the third map, and the third map is configured to control the cooling fan when the value of the temperature to be cooled reaches a predetermined third rotation speed when the fan rotation speed is 0. rotate The fan rotation speed may be switched to a predetermined auto-idle rotation speed when the fan rotation speed rises from a value less than the start-up temperature to the third rotation start-up temperature, and may be configured to switch the fan rotation speed to 0 when the value of the temperature to be cooled drops to a predetermined third rotation drop temperature lower than the third rotation start-up temperature while the fan rotation speed is at the auto-idle rotation speed.

[0013] The third map may be common to the first map.

[0014] The object to be cooled by the cooler is a refrigerant for cooling a cooling target device mounted on the work machine, the work machine is equipped with an abnormally high temperature detection device that detects an abnormally high temperature of the cooling target device, and the control device may rotate the cooling fan at a third fan rotation speed that is higher than the second fan rotation speed when the abnormally high temperature detection device detects an abnormally high temperature and the temperature of the cooling target is equal to or higher than a third specified temperature that is set to a value higher than the second rotation start temperature.

[0015] The control device may return control of the cooling fan rotation speed to control based on the second map when the value of the temperature to be cooled drops to a fourth specified temperature that is lower than the third specified temperature while the cooling fan is rotating at the third fan rotation speed.

[0016] The second map may be configured to set the fan rotation speed to a fourth fan rotation speed that is higher than the second fan rotation speed when the value of the temperature to be cooled rises to a fourth rotation rise temperature that is higher than the first specified temperature while the fan rotation speed is at the second fan rotation speed, and to reduce the fan rotation speed to the second fan rotation speed when the value of the temperature to be cooled falls to a predetermined fourth rotation fall temperature that is lower than the fourth rotation rise temperature and higher than the first specified temperature while the fan rotation speed is at the fourth fan rotation speed.

[0017] The plurality of fan control maps may include a fourth map, and the fourth map is configured to set the fan rotation speed to a value greater than 0 when the value of the cooling object temperature rises from a value less than the second rotation rise temperature to the second rotation rise temperature while the fan rotation speed is 0, set the fan rotation speed to a predetermined fifth fan rotation speed lower than the second fan rotation speed when the value of the cooling object temperature is equal to or greater than the first specified temperature, set the fan rotation speed to a higher value within a range less than the fifth fan rotation speed as the cooling object temperature increases when the value of the cooling object temperature is equal to or greater than the second rotation rise temperature and less than the first specified temperature, and reduce the fan rotation speed to 0 when the value of the cooling object temperature falls to the second rotation drop temperature while the fan rotation speed is not 0, and the control device may control the cooling fan based on the second map when the rotation speed of the electric motor is set to a high value, and control the cooling fan based on the fourth map when the rotation speed of the electric motor is set to a low value.

[0018] The fourth map may be configured to set the fan rotation speed to a sixth fan rotation speed that is higher than the fifth fan rotation speed when the value of the temperature to be cooled rises to a fourth rotation rise temperature that is higher than the first specified temperature while the fan rotation speed is at the fifth fan rotation speed, and to reduce the fan rotation speed to the fifth fan rotation speed when the value of the temperature to be cooled falls to a predetermined fourth rotation fall temperature that is lower than the fourth rotation rise temperature and higher than the first specified temperature while the fan rotation speed is at the sixth fan rotation speed.

[0019] The cooler may be a radiator for cooling cooling water that cools equipment including the electric motor, the cooling fan may be a radiator fan provided in the radiator, and the temperature detection device may detect the temperature of the cooling water as the temperature of the object to be cooled.

[0020] The cooler may be a radiator for cooling cooling water that cools equipment including the electric motor, the cooling fan may be a radiator fan provided in the radiator, and the temperature detection device may detect the temperature of the cooling water as the temperature of the object to be cooled.

[0021] The work machine may include a hydraulic pump driven by the electric motor and a hydraulic actuator driven by the hydraulic pressure of the hydraulic oil discharged by the hydraulic pump, the cooler may be an oil cooler for cooling the hydraulic oil, the cooling fan may be an oil cooler fan provided in the oil cooler, and the temperature detection device may detect the temperature of the hydraulic oil as the temperature to be cooled.

[0022] The work machine may include a hydraulic pump driven by the electric motor and a hydraulic actuator driven by the hydraulic pressure of the hydraulic oil discharged by the hydraulic pump, the cooler may be an oil cooler for cooling the hydraulic oil, the cooling fan may be an oil cooler fan provided in the oil cooler, and the temperature detection device may detect the temperature of the hydraulic oil as the temperature to be cooled.

[0023] The work machine may include a hydraulic pump driven by the electric motor and a hydraulic actuator driven by the hydraulic pressure of hydraulic oil discharged from the hydraulic pump, the cooler may include a radiator for cooling cooling water that cools devices including the electric motor, and an oil cooler for cooling the hydraulic oil, and the cooling fans may include a radiator fan provided in the radiator and an oil cooler fan provided in the oil cooler, the temperature detection device detects the temperature of the cooling water and the temperature of the hydraulic oil as the temperature to be cooled, the memory device stores a plurality of fan control maps for the radiator fan indicating a characteristic of the rotation speed of the radiator fan relative to the temperature of the cooling water, and a plurality of fan control maps for the oil cooler fan indicating a characteristic of the rotation speed of the oil cooler fan relative to the temperature of the hydraulic oil, and the control device may control the rotation speed of the radiator fan based on the plurality of fan control maps for the radiator fan, and control the rotation speed of the oil cooler fan based on the plurality of fan control maps for the oil cooler fan. [Effects of the Invention]

[0024] With the above configuration, the rotation of the cooling fan can be controlled in accordance with the switching position of the operation lock device, thereby realizing reduction in noise, reduction in power consumption, and prevention of overcooling. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. [Figure 2] FIG. [Figure 3] FIG. 4 is a diagram showing a first map group. [Figure 4A] 10 is a flowchart for controlling a cooling fan based on a first map group. [Figure 4B] 10 is a flowchart for controlling a cooling fan based on a first map group. [Figure 5] FIG. 10 is a diagram showing a second map group. [Figure 6A]10 is a flowchart for controlling a cooling fan based on a second map group. [Figure 6B] 10 is a flowchart for controlling a cooling fan based on a second map group. [Figure 6C] 10 is a flowchart for controlling a cooling fan based on a second map group. [Figure 7] FIG. 2 is an overall side view of the work machine. [Figure 8] FIG. 2 is a perspective view showing the right rear portion of the work machine excluding the travel device and the work device. [Figure 9] FIG. 2 is a perspective view showing the structure inside the hood of the work machine. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0027] First, the overall configuration of the work machine 1 of this embodiment will be described with reference to Figures 7 to 9 etc. In this embodiment, the work machine 1 is a swivel-type excavation machine called a backhoe. The work machine 1 comprises a machine body (swivel base) 2, a traveling device 10, a work device 20, etc.

[0028] The machine body 2 is mounted on the upper part of the traveling device 10 via a vertical pivot shaft (not shown). As shown in Fig. 7, the machine body 2 is mounted so as to be rotatable in the horizontal direction relative to the traveling device 10 around the vertical axis X of the pivot shaft.

[0029] In the following description of the work machine 1, the front-to-rear direction refers to the front-to-rear direction of the machine body 2, regardless of the relative rotational position of the traveling device 10 with respect to the machine body 2. In Figures 7 to 9, arrow F extends forward as seen from the machine body 2. This direction coincides with the horizontal line of sight of an operator seated in the driver's seat 4 shown in Figure 7 when facing forward. For the machine body 20, the rear is the horizontal direction directly opposite to that of arrow F.

[0030] In the following description of the work machine 1, the left and right direction refers to the left and right direction of the machine body 2 (the width direction of the machine body 2) regardless of the relative rotation position of the traveling device 10 with respect to the machine body 2. In Figures 8 and 9, arrow L extends to the left of the machine body 2.

[0031] When arrow L is illustrated together with arrow F as in Figures 8 and 9, arrow L extends from the starting point of arrow F in a leftward direction as viewed from arrow F. The direction of arrow L corresponds to the horizontal leftward direction as viewed from the operator sitting in the driver's seat 4. For the aircraft 2, the rightward direction is the horizontal direction directly opposite to that of arrow L.

[0032] Hereinafter, when the position or direction of each component or part of the work machine 1 is described, it will be assumed that the position or direction is relative to the machine body 2 as described above.

[0033] On top of the machine body 2 of the work machine 1, there are provided a driver's seat 4 where an operator (worker) sits, and a protective structure 6 that protects the driver's seat 4 from the front, back, left, right, and above. In this embodiment, the protective structure 6 is a cabin. In another embodiment, the protective structure 6 may be a canopy.

[0034] Each side of the protective structure 6 is provided with a transparent portion (so-called window) that allows the surroundings to be seen from the driver's seat 4. The protective structure 6 separates the interior space in which the driver's seat 4 is located from the outside.

[0035] An operating device 5 for operating the work machine 1 is provided around the driver's seat 4 inside the protective structure 6. The operator can operate the operating device 5 while seated in the driver's seat 4.

[0036] The traveling device 10 will be described assuming that the front-to-rear directions of the traveling device 10 and the machine body 2 are the same. The traveling device 10 has a traveling frame (track frame) 11 and a pair of left and right traveling mechanisms 12. The machine body 2 is supported on top of the traveling frames 11. The traveling mechanism 12 shown in the figure is a crawler-type traveling mechanism, but it may also be a tire (wheel)-type traveling mechanism, for example.

[0037] The travel mechanisms 12 are provided on the left and right sides of the travel frame 11. Each travel mechanism 12 has an idler 13, a drive wheel (drive sprocket) 14, a plurality of rollers 15, an endless crawler belt 16, and travel motors ML and MR.

[0038] The idler 13 is disposed at the front of the traveling frame 11. The drive wheel (drive sprocket) 14 is disposed at the rear of the traveling frame 11. A plurality of rollers 15 are provided between the idler 13 and the drive wheel 14. The crawler belt 16 is wound around the idler 13, the drive wheel 14, and the roller 15.

[0039] The left traveling motor ML is included in the traveling mechanism 12 provided on the left side of the traveling frame 11. The right traveling motor MR is included in the traveling mechanism 12 provided on the right side of the traveling frame 11. The traveling motors ML and MR are hydraulic motors.

[0040] In the left and right traveling mechanisms 12, the traveling motors ML and MR are respectively provided coaxially with the drive wheels 14, and their output shafts are directly connected to the rotational axes of the drive wheels 14. Note that a transmission mechanism such as a reduction gear train may be interposed between the traveling motors ML and MR and the drive wheels 14, and they do not necessarily have to be arranged coaxially with the drive wheels 14.

[0041] The rotation of the drive wheels 14 driven by the respective travel motors ML and MR drives the crawler belts 16, which in turn drives the idlers 13 and rollers 15. The drive of the left and right crawler belts 16 causes the travel device 10 to travel.

[0042] The output rotation speed and output rotation direction of the left and right travel motors ML and MR can be driven and controlled independently of each other. By making the output rotation speed and output rotation direction the same for the left and right travel motors ML and MR, the travel device 10, i.e., the work machine 1, moves straight forward or backward. By making the rotation speeds of the left and right travel motors ML and MR different or by making the rotation directions different, the work machine 1 turns.

[0043] A dozer 18 is attached to the front of the traveling frame 11 and extends forward of the traveling device 10. The dozer 18 swings up and down by the extension and contraction of a dozer cylinder C5. The dozer cylinder C5 is attached to the traveling frame 11. The dozer cylinder C5 is a hydraulic cylinder.

[0044] The machine body 2 is supported on a traveling frame 11 via a slewing bearing 3 so as to be rotatable about an axis X. A slewing motor MT is provided inside the machine body 2. The slewing motor MT is a hydraulic motor, which is a type of hydraulic actuator. The machine body 2 swivels about the axis X by the power of the slewing motor MT.

[0045] A swing bracket 24 is provided at the front of the machine body 2 so as to be rotatable left and right relative to the machine body 2 around a vertical axis (an axis in the up-down direction). The working device 20 is supported at the front of the machine body 2 via the swing bracket 24. Hereinafter, the working device 20 will be described assuming that the front-to-rear direction of the working device 20 coincides with the front-to-rear direction of the machine body 2.

[0046] The work device 20 has a boom 21, an arm 22, and a bucket (hydraulic attachment) 23. The base end of the boom 21 is pivotally mounted to a swing bracket 24 so as to be rotatable about a horizontal axis. This allows the boom 21 to swing up and down and back and forth relative to the machine body 2. The horizontal axis is an axis having a horizontal axis that runs along the left-right direction of the machine body 2.

[0047] The arm 22 is pivotally mounted on the tip of the boom 21 so as to be rotatable about a horizontal axis. This allows the arm 22 to swing back and forth or up and down. The bucket 23 is provided on the tip of the arm 22 so as to be capable of scooping and dumping operations.

[0048] The scooping operation and dumping operation are relative rotations of the bucket 23 with respect to the arm 22, with the scooping operation being rotation toward the boom 21 and arm 22 and the dumping operation being rotation away from the boom 21 and arm 22.

[0049] The work device 20 has a boom cylinder C2, an arm cylinder C3, and a bucket cylinder C4 as hydraulic actuators (hydraulic cylinders) for operating the boom 21, the arm 22, and the bucket 23. In addition, the machine body 2 is provided with a swing cylinder C1, which is a hydraulic actuator (hydraulic cylinder) for rotating the swing bracket 24.

[0050] The swing bracket 24 swings left and right relative to the machine body 2 as the swing cylinder C1 expands and contracts. The boom 21 swings up and down or front and back relative to the swing bracket 24 as the boom cylinder C2 expands and contracts. The arm 22 swings up and down or front and back relative to the boom 21 as the arm cylinder C3 expands and contracts. The bucket 23 performs scooping and dumping operations as the bucket cylinder (work tool cylinder) C4 expands and contracts.

[0051] Instead of or in addition to the bucket 23, another working tool (hydraulic attachment) that can be driven by a hydraulic actuator can be attached to the tip of the arm 22. Examples of other working tools include a hydraulic breaker, a hydraulic crusher, an angle broom, an earth auger, a pallet fork, a sweeper, a mower, and a snow blower.

[0052] The work machine 1 performs work such as excavation by driving the travel device 10 with travel motors ML and MR, driving the work device 20 and dozer 18 with hydraulic cylinders C1 to C5, and swinging the machine body 2 with a swing motor MT.

[0053] That is, the work machine 1 is equipped with travel motors ML, MR, swing motor MT, and hydraulic cylinders C1 to C5 as hydraulic actuators for hydraulically operating each part. Hereinafter, unless otherwise specified, all of these hydraulic actuators will be referred to simply as "hydraulic actuators."

[0054] In order to operate these hydraulic actuators, the work machine 1 is provided with a hydraulic system (hydraulic circuit K) as shown in Figure 2, which will be described in detail later.

[0055] As shown in Figure 7, inside the hood 2a formed in the rear part of the protective structure (cabin) 6 of the aircraft body 2, as shown in Figure 9, a battery unit 30 consisting of a combination of multiple battery packs 31, 32 is supported by a support frame 90 with the battery packs 31, 32 arranged side by side on the left and right of the aircraft body 2, and is installed on a base 2c that forms the bottom plate of the aircraft body (swivel base) 2.

[0056] As can be seen in Figure 8, the hood 2a of the aircraft body 2 bulges out to the right beyond the right end of the protective structure 6. Utilizing the space within the right bulging portion of this hood 2a, a motor-pump assembly 91, which combines an electric motor 9 as a prime mover with hydraulic pumps P1 and P2, is installed on the base 2c to the right of the battery unit 30, as shown in Figure 9.

[0057] Similarly, in the space above the motor-pump assembly 91 within the right-side expansion section of the bonnet 2a, as shown in FIG. 8, a radiator 35 and an oil cooler 37 are provided side-by-side in the front and rear direction on the right side of the battery unit 30 (in this embodiment, the radiator 35 is positioned in front of the oil cooler 37).

[0058] Thus, the radiator fan 35a of the radiator 35 and the oil cooler fan 37a of the oil cooler 37 are arranged side by side in the front and rear direction, and both face the right side surface of the bonnet 2a.

[0059] An air outlet (not shown) is provided on the right cover 2b of the hood 2a, and the hot exhaust air from the radiator fan 35a and the oil cooler fan 37a is discharged outside the aircraft body 2 through the air passage and air outlet defined by the shroud 96.

[0060] This right cover 2b can be opened and closed as shown in FIG. 8, and by opening the right cover 2b, the radiator fan 35a, oil cooler fan 37a, etc. can be accessed for maintenance or the like.

[0061] 1 is disposed inside the hood 2a on the left side of the battery unit 30. Fan motor 35b that drives radiator fan 35a, fan motor 37b that drives oil cooler fan 37a, etc. receive power from this low-voltage battery 33. The low-voltage battery 33 can be charged with power supplied by battery packs 31 and 32 of the battery unit 30.

[0062] At the top of the support frame 90, converters 97 including an inverter 38 and a converter 40, which will be described later, are provided to supply power from the battery packs 31, 32 to the electric motor 9 and also to the low-voltage battery 33.

[0063] In this embodiment, hereafter, electrical equipment such as the electric motor 9 that operates by receiving high-voltage power from the battery packs 31 and 32 may be referred to as high-voltage equipment, and electrical equipment (electrical components) that operates by receiving low-voltage power from the low-voltage battery 33 may be referred to as low-voltage equipment.

[0064] Next, we will explain each component of the electrical system of the work machine 1 shown in Figure 1. Figure 1 is a block diagram showing the electrical system of the work machine 1. The work machine 1 is equipped with a control device 7, which has a CPU 7a and a storage unit 7b.

[0065] The CPU 7a controls the operation of each part of the work machine 1 shown in Fig. 1. The storage unit 7b is composed of a volatile memory, a non-volatile memory, etc. Information, data, programs, etc. used by the CPU 7a to control the operation of each part are stored in the storage unit 7b in a readable and writable manner.

[0066] The work machine 1 is provided with a memory device for storing such data, programs, etc. as a memory unit 7b incorporated into the control device 7, but such a memory device may also be provided separately from the control device 7, for example in the form of an external memory.

[0067] The operating device 5 has operating members such as a work operating lever 5a, a travel operating lever 5b, an unload lever 5c, an accelerator dial 5d, and a mode selection switch (SW) 5e. The operating device 5 also has a potentiometer, a switch, a sensor, or the like (not shown) for detecting whether or not each of the operating members 5a to 5e is operated, the operating position, or the amount of operation.

[0068] The working operation lever 5a is a member that controls the operation of the working device 20. The traveling operation lever 5b is a member that controls the operation of the traveling device 10. For convenience, the working operation lever 5a and the traveling operation lever 5b are each shown as a single block in FIG. 1, but in reality, multiple levers corresponding to the working operation lever 5a may be provided, or multiple levers corresponding to the traveling operation lever 5b may be provided. Note that these operation members may also be configured as dials, switches, or the like other than levers.

[0069] The unload lever 5c is a member that can be switched between a loaded position (first position, permitted position) that permits operation of the hydraulic actuator, and an unloaded position (second position, prohibited position) that does not permit (prohibit) operation of the working implement 20. The unload lever 5c is installed, for example, to the side of the driver's seat 4 (FIG. 1) so that it can swing up and down, with the lower limit position of the vertical swing range being the loaded position and the upper limit position being the unloaded position.

[0070] By swinging the unload lever 5c downward to the load position (first position, lowered position), the passage for the operator to get on and off the cab 4R is closed. By swinging the unload lever 5c upward to the unload position (second position, raised position), the passage is opened.

[0071] The accelerator dial 5d is rotated to set a target rotation speed of the electric motor 9. The target rotation speed of the electric motor 9 can be changed by changing the operating position of the accelerator dial 5d, i.e., the rotation angle. The control device 7 calculates a command value for the rotation speed of the electric motor 9 according to the operating position (operation amount) of the accelerator dial 5d, and commands the electric motor 9 to rotate at the rotation speed of the command value.

[0072] The mode selection SW5e is a switch that is operated to select either a normal mode (first mode) for controlling the drive of the electric motor 9 or an ECO mode (ecology mode, second mode) that reduces power consumption more than the normal mode.

[0073] When the normal mode is selected by the mode selection SW5e, a high idle rotation speed MS1 (see FIG. 5), which is a motor rotation speed for high speed rotation, is set as the motor rotation speed MS of the electric motor 9. Note that the value of the high idle rotation speed MS1 can be, for example, 2200 rpm.

[0074] On the other hand, when the ECO mode is selected by the mode selection SW5e, a low idle rotation speed MS2 (see FIG. 5), which is a motor rotation speed for low speed rotation, is set as the motor rotation speed MS of the electric motor 9. Note that the value of the low idle rotation speed MS2 can be, for example, 1000 rpm.

[0075] Furthermore, when performing auto-idling control as described below, the electric motor 9 is driven at an idle rotation speed MS3 (see FIG. 5) that is lower than the low idle rotation speed MS2. The value of the idle rotation speed MS3 may be set to, for example, 250 rpm.

[0076] A starter SW (switch) 8 is provided inside the protective structure 6 and can be operated by an operator seated in the driver's seat 4. The starter SW 8 is operated to start and stop the work machine 1.

[0077] By turning on the starter SW8, the control device 7 starts the electric motor 9, which is the prime mover, and starts each part of the work machine 1. By turning off the starter SW8, the control device 7 stops the electric motor 9 and stops each part of the work machine 1.

[0078] The electric motor 9, which is the prime mover of the work machine 1, is configured by, for example, a permanent magnet embedded three-phase AC synchronous motor. The inverter 38 is a motor drive device that drives the electric motor 9. The inverter 38 is connected to the electric motor 9 and a junction box 39.

[0079] In addition to the inverter 38, the junction box 39 is connected to the battery unit 30, the DC-DC converter 40, and the charging port 41. The junction box 39 outputs the power output from the battery unit 30 to the inverter 38 and the DC-DC converter 40.

[0080] The inverter 38 converts DC power input from the battery unit 30 via the junction box 39 into three-phase AC power and supplies the three-phase AC power to the electric motor 9. This drives the electric motor 9. The inverter 38 can also arbitrarily adjust the current and voltage of the power supplied to the electric motor 9. The control device 7 controls the operation of the inverter 38 to drive or stop the electric motor 9.

[0081] The motor rotation speed detection device 42 is composed of a sensor, an encoder, a pulse generator, or the like that detects the rotation speed (actual rotation speed) of the electric motor 9. The control device 7 controls the driving of the electric motor 9 by the inverter 38 based on the rotation speed (actual rotation speed) of the electric motor 9 detected by the motor rotation speed detection device 42.

[0082] The control device 7 controls the driving of the electric motor 9 by the inverter 38 so that the actual rotation speed of the electric motor 9 detected by the motor rotation speed detection device 42 matches the target rotation speed (the set value by the accelerator dial 5d or the predetermined rotation speeds R1 to R3 described below).

[0083] The DC-DC converter 40 is a voltage conversion device that converts the voltage of the direct current input from the battery unit 30 via the junction box 39 into a different voltage. In this embodiment, the DC-DC converter 40 is a step-down converter that converts the high voltage of the battery unit 30 into a predetermined low voltage that is suitable for the above-mentioned low-voltage devices (electrical components) provided in the work machine 1.

[0084] The DC-DC converter 40 converts the voltage and then supplies the power to the low-voltage battery 33. In addition to the components shown in FIG. 1 , the work machine 1 is also equipped with the aforementioned low-voltage devices (electrical components) such as lighting and heaters, and these low-voltage devices (electrical components) operate using power from the low-voltage battery 33.

[0085] Charging port 41 has a connector (not shown) into which a charging cable (not shown) is fitted, and a connection detection device 41a. Charging port 41 is connected to an external power source (commercial power source, etc.) via the charging cable. Connection detection device 41a is made up of a sensor and the like that detects that the charging cable is fitted into charging port 41 and the external power source is connected.

[0086] Junction box 39 outputs power input from an external power source via a charging cable to charging port 41 to battery unit 30. Battery unit 30 is charged with power input from charging port 41 via junction box 39.

[0087] The battery unit 30 has a plurality of battery packs 31 and 32. Each of the battery packs 31 and 32 is a secondary battery (storage battery) such as a lithium ion battery, which is made up of at least one battery.

[0088] When each battery pack 31, 32 is configured with a plurality of batteries, the plurality of batteries are electrically connected in series and / or in parallel. Furthermore, the battery constituting each battery pack 31, 32 has a plurality of cells therein, and the plurality of cells are electrically connected in series and / or in parallel.

[0089] Each of the battery packs 31, 32 has an electrical capacity sufficient to operate each part of the work machine 1 for a predetermined period of time. The battery packs 31, 32 are connected in parallel to each other.

[0090] In this embodiment, the battery unit 30 is provided with two battery packs 31 and 32, but the number of battery packs included in the battery unit 30 is not limited to two, and may be one, or three or more.

[0091] Connection switching units 31a, 32a are provided in the battery packs 31, 32. The connection switching units 31a, 32a are each configured with, for example, a relay or a switch, and are capable of switching between a connected state and a disconnected state.

[0092] The control device 7 switches one of the connection switching units 31a, 32a to a connected state and the other connection switching unit to a disconnected state, thereby outputting power from one of the battery packs 31, 32 to the junction box 39 and stopping the output of power from the other battery pack. In other words, the control device 7 controls the output and stop of power from each of the battery packs 31, 32.

[0093] The control device 7 also switches the internal connection state of the junction box 39 to connect or disconnect the inverter 38, DC-DC converter 40, or charging port 41 to each of the battery packs 31, 32. The junction box 39 and connection switching units 31a, 32a are connection switching devices that switch the connection and disconnection of the inverter 38, DC-DC converter 40, and charging port 41 to each of the battery packs 31, 32.

[0094] 1, the BMUs 31b and 32b are provided in the corresponding battery packs 31 and 32, but the BMUs 31b and 32b may be built into the corresponding battery packs 31 and 32 or may be installed outside the corresponding battery packs 31 and 32.

[0095] The BMU 31b monitors and controls the corresponding battery pack 31. The BMU 32b monitors and controls the corresponding battery pack 32. Specifically, the BMUs 31b and 32b control the opening and closing of relays provided inside the battery packs 31 and 32 to control the start and stop of power supply from the battery packs 31 and 32. The BMUs 31b and 32b also detect the temperature, voltage, current, terminal voltage of the internal cells, etc. of the battery packs 31 and 32.

[0096] Furthermore, the BMUs 31b and 32b detect the remaining capacity (remaining energy) of the battery packs 31 and 32 by a voltage measurement method based on the terminal voltage of the cells inside the battery packs 31 and 32, for example.

[0097] The method for detecting the remaining capacity of the battery packs 31 and 32 is not limited to the voltage measurement method, and other methods such as a coulomb counter method, a battery cell modeling method, an impedance track method, etc. Also, a capacity detection unit for detecting the remaining capacity of the battery packs 31 and 32 may be provided separately from the BMUs 31b and 32b.

[0098] The low-voltage battery 33 is a storage battery with a lower voltage than the battery unit 30. The low-voltage battery 33 is charged with power supplied from the DC-DC converter 40. The low-voltage battery 33 supplies power to the electrical components provided in the work machine 1 as described above.

[0099] The radiator 35 cools the cooling water for cooling the high-heat-generating electrical devices such as the electric motor 9, inverter 38, DC-DC converter 40, and battery unit 30. The cooling water is not simply water, but is made of a liquid that will not freeze even in cold regions, for example.

[0100] The high-heat-generating electrical equipment that is the target of cooling by the radiator 35 is electrical equipment that generates more heat than other electrical equipment in the work machine 1 when operated with electric power, and corresponds to the high-power equipment mentioned above. Each of these high-power equipment is equipped with a temperature sensor, which functions as an abnormally high temperature detection device 49 for detecting abnormally high temperatures in each high-power equipment.

[0101] Each high-power appliance has a set upper temperature limit, and when the actual temperature reaches this upper limit, the appliance stops operating to protect itself. When the temperature remains high enough to reach this upper limit, the appliance reduces its output (delayed output). The abnormally high temperature detected by the abnormally high temperature detector 49 is the temperature at which this delay is initiated, before the upper limit is reached.

[0102] The radiator 35 has a heat exchanger (not shown), a radiator fan 35a, and a fan motor 35b. The radiator fan 35a rotates upon receiving output from the fan motor 35b, and releases heat recovered from the coolant by the heat exchanger to the outside of the aircraft body 2. The fan motor 35b is driven by power from the low-voltage battery 33. A fan rotation speed detector 43 detects the rotation speed of the radiator fan 35a.

[0103] The cooling pump 36, together with the radiator 35 and the high-heat-generating electrical equipment, is provided on a cooling water passage (not shown) arranged inside the fuselage 2. The cooling pump 36 discharges cooling water into the cooling water passage.

[0104] The oil cooler 37 cools the hydraulic oil that has passed through hydraulic devices such as the hydraulic actuators ML, MR, MT, and C1 to C5 described above, hydraulic pumps P1 and P2 described below, and a control valve unit CV (shown in FIG. 2, etc.) described below. That is, the object to be cooled by the oil cooler 37 is the hydraulic oil.

[0105] The oil cooler 37 has a heat exchanger (not shown), an oil cooler fan 37a, and a fan motor 37b. The oil cooler fan 37a rotates upon receiving output from the fan motor 37b, and releases heat recovered from the hydraulic oil by the heat exchanger to the outside of the aircraft body 2. The fan motor 37a is driven by power from the low-voltage battery 33. A fan rotation speed detector 44 detects the rotation speed of the oil cooler fan 37a.

[0106] The display device 45 is composed of a liquid crystal display, a touch panel, or the like, and displays various information. The water temperature detection device 46 detects the temperature of the cooling water circulating in the cooling water passage. The oil temperature detection device 47 detects the temperature of the hydraulic oil, particularly the temperature of the hydraulic oil at the stage where it is used to operate the hydraulic actuator and then returned to a hydraulic oil tank 59 (described later).

[0107] The AI ​​(auto-idling)-SW (switch) 48 is a pressure sensor that operates with the hydraulic pressure of the hydraulic oil supplied to the aforementioned hydraulic actuators C1 to C5, ML, MR, and MT. The AI-SW 48 is turned on when at least one of the hydraulic actuators C1 to C5, ML, MR, and MT is operating, and is turned off when none of these hydraulic actuators is operating.

[0108] In other words, the AI-SW 48 detects whether any one of the working implement 20, the traveling implement 10, etc., which are the targets of drive by the hydraulic actuators C1 to C5, ML, MR, and MT, is operating.

[0109] Next, we will explain the hydraulic circuit (hydraulic system) provided in the work machine 1. Fig. 2 is a diagram showing a hydraulic circuit K provided in the work machine 1. The hydraulic circuit K is provided with hydraulic devices such as hydraulic actuators C1 to C5, ML, MR, MT, a control valve unit CV, hydraulic pumps P1 and P2, a hydraulic oil tank 59, an oil cooler 37, operation valves PV1 to PV6, an unload valve 58, and an oil passage 50.

[0110] Of the multiple hydraulic pumps P1 and P2 provided, one is an actuation hydraulic pump P1 and the other is a control hydraulic pump P2. These hydraulic pumps P1 and P2 are driven by the power of an electric motor 9.

[0111] 9, a motor-pump assembly 91 installed inside the hood 2a has an electric motor 9 and hydraulic pumps P1 and P2. The output shaft of the electric motor 9 is extended to function as the input shaft (pump shaft) of the hydraulic pumps P1 and P2.

[0112] The hydraulic actuation pump P1 draws hydraulic oil stored in the hydraulic oil tank 59 and then discharges the hydraulic oil toward the control valve unit CV. For convenience, one hydraulic actuation pump P1 is shown in Fig. 2, but the number is not limited to this, and an appropriate number of hydraulic actuation pumps P1 may be provided so that hydraulic oil can be supplied to each of the hydraulic actuators C1 to C5, ML, MR, and MT.

[0113] The control hydraulic pump P2 outputs hydraulic pressure for signals, controls, etc. by drawing in and then discharging hydraulic oil stored in the hydraulic oil tank 59. In other words, the control hydraulic pump P2 supplies (discharges) pilot oil for controlling the positions (switching) of the control valves V1 to V8. An appropriate number of control hydraulic pumps P2 may be provided.

[0114] The control valve unit CV is made up of a combination of multiple control valves V1 to V8. Each control valve V1 to V8 controls (adjusts) the flow rate of hydraulic oil output from the hydraulic pumps P1 and P2 to each of the hydraulic actuators C1 to C5, ML, MR, and MT.

[0115] Of the control valves V1 to V8, the control valves V1 to V4 are used to control the work device 20. The swing control valve V1 controls the flow rate and flow direction of the hydraulic oil supplied to the swing cylinder C1. The boom control valve V2 controls the flow rate and flow direction of the hydraulic oil supplied to the boom cylinder C2. The arm control valve V3 controls the flow rate and flow direction of the hydraulic oil supplied to the arm cylinder C3. The bucket control valve V4 controls the flow rate and flow direction of the hydraulic oil supplied to the bucket cylinder C4.

[0116] The dozer control valve V5 controls the flow rate of hydraulic oil supplied to the dozer cylinder C5. The left travel control valve V6 controls the flow rate of hydraulic oil supplied to the left travel motor ML. The right travel control valve V7 controls the flow rate of hydraulic oil supplied to the right travel motor MR. The swing control valve V8 controls the flow rate of hydraulic oil supplied to the swing motor MT.

[0117] In addition, the "left" in the left travel motor ML, right travel motor MR, left travel control valve V6, and right travel control valve V7 means that it is for the left travel mechanism 12, and the "right" means that it is for the right travel mechanism 12, and "left" and "right" do not necessarily refer to the actual left-right positional relationship.

[0118] The operating valves (remote control valves) PV1 to PV6 are solenoid valves that operate in response to the operation of operating levers 5a, 5b (Fig. 1) provided on the operating device 5. Pilot oil acts on each control valve V1 to V8 in proportion to the operating amount (operation amount) of each operating valve PV1 to PV6, causing the spool of each control valve V1 to V8 to move linearly.

[0119] Then, hydraulic oil is supplied to the hydraulic actuators C1-C5, ML, MR, and MT to be controlled at a flow rate proportional to the amount of movement of the spool of each control valve V1-V8. In this way, each hydraulic actuator C1-C5, ML, MR, and MT is driven according to the amount of hydraulic oil supplied from each control valve V1-V8.

[0120] That is, by operating the operating levers 5a, 5b, the hydraulic oil acting as pilot oil on the control valves V1 to V8 is adjusted, thereby controlling the control valves V1 to V8. The flow rate and flow direction of the hydraulic oil supplied from the control valves V1 to V8 to the hydraulic actuators C1 to C5, ML, MR, and MT are adjusted, thereby controlling the driving and stopping of the hydraulic actuators C1 to C5, ML, MR, and MT.

[0121] The oil passage 50 is configured by, for example, a hose or a pipe made of a material such as metal. The oil passage 50 is a flow path that connects each part provided in the hydraulic circuit K and flows hydraulic oil or pilot oil to each part. The oil passage 50 includes a first oil passage 51, a second oil passage 52, a first suction oil passage 54, a second suction oil passage 55, and a restriction oil passage 57.

[0122] The first suction oil passage 54 is a flow path through which the hydraulic oil drawn by the actuation hydraulic pump P1 from the hydraulic oil tank 48 flows. The second suction oil passage 55 is a flow path through which the hydraulic oil drawn by the control hydraulic pump P2 from the hydraulic oil tank 59 flows.

[0123] The first oil passage 51 is a flow path through which the hydraulic oil discharged from the hydraulic pump P1 flows toward the control valves V1 to V8 of the control valve unit CV. The first oil passage 51 branches into a plurality of passages within the control valve unit CV and is connected to each of the control valves V1 to V8.

[0124] The second oil passage 52 is a flow path that allows the hydraulic oil that has passed through the control valves V1 to V8 to flow toward the hydraulic oil tank 48. The hydraulic oil tank 59 stores the hydraulic oil. The second oil passage 52 includes a reciprocating oil passage 52a and a discharge oil passage 52b.

[0125] The reciprocating oil passages 52a are a pair of oil passages interposed between each of the control valves V1 to V8 and the hydraulic actuators C1 to C5, ML, MR, and MT that are the respective control targets. The reciprocating oil passages 52a are flow paths that supply hydraulic oil from the connected control valves V1 to V8 to the hydraulic actuators C1 to C5, ML, MR, and MT, and return hydraulic oil from the hydraulic actuators C1 to C5, ML, MR, and MT to the control valves V1 to V8.

[0126] One end of the oil discharge passage 52b branches into a plurality of passages which are connected to the control valves V1 to V8. The other end of the oil discharge passage 52b is connected to a hydraulic oil tank 59.

[0127] A portion of the hydraulic oil that flows through the first oil passage 51 to one of the control valves V1 to V8 passes through the control valve V1 to V8 and passes through one of a pair of oil passages serving as the reciprocating oil passage 52a, and is supplied to the hydraulic actuators C1 to C5, ML, MR, and MT to be controlled.

[0128] The hydraulic oil discharged from the hydraulic actuators C1 to C5, ML, MR, and MT returns to the control valves V1 to V8 connected through the other of the pair of oil passages serving as the reciprocating oil passage 52a, passes through the control valves V1 to V8, and flows to the discharge oil passage 52b.

[0129] Furthermore, the hydraulic oil that has flowed through the first oil passage 51 to any of the control valves V1 to V8 passes through the control valves V1 to V8 and flows to the discharge oil passage 52b without being supplied to the hydraulic actuators C1 to C5, ML, MR, and MT.

[0130] An oil cooler 37 is provided in the oil discharge passage 52b. The oil cooler 37 cools the hydraulic oil that flows from any of the control valves V1 to V8 through the oil discharge passage 52b. The hydraulic oil cooled by the oil cooler 37 returns to the hydraulic oil tank 59 through the oil discharge passage 52b.

[0131] As described above, the oil passages 54, 51, and 52 are arranged to circulate the hydraulic oil between the hydraulic oil tank 59, the hydraulic pump P1, and the control valves V1 to V8 of the control valve unit CV (and some of the hydraulic oil to the hydraulic actuators C1 to C5, ML, MR, and MT).

[0132] The limit oil passage 57 is a flow path that allows the hydraulic oil discharged by the control hydraulic pump P2 to flow to the operation valves PV1 to PV6. One end of the limit oil passage 57 is connected to the control hydraulic pump P2, and the other end branches into multiple passages that are connected to the primary side ports (primary ports) of each of the operation valves PV1 to PV6.

[0133] The operation valves PV1 to PV6 are solenoid valves, and their openings are adjusted based on command signals output from the control device 7. The flow rate of pilot pressure oil to the control valves V1 to V8 is adjusted by adjusting the openings.

[0134] An unloading valve 58, which is a two-position switching valve, is provided in the restricted oil passage 57. The unloading valve 58 is a two-position switching valve having an oil supply position 58a and an oil cutoff position 58b as switching positions, and switches to either the oil supply position 58a or the oil cutoff position 58b in conjunction with the operation of the unloading lever 5c (FIG. 1).

[0135] When the unload lever 5c is operated to the load position (lowered position), the unload valve 58 is switched to the oil supply position 58a (load position), and the hydraulic oil discharged from the control hydraulic pump P2 to the restricted oil passage 57 is supplied to the operating valves PV1 to PV6, making the control valves V1 to V8 operable.

[0136] This allows the supply of hydraulic oil from the operating hydraulic pump P1 to the hydraulic actuators C1 to C5, ML, MR, and MT, and permits the operation of these hydraulic actuators. Note that the hydraulic oil discharged from the operation valves PV1 to PV6 returns to the hydraulic oil tank 59 through a separate discharge oil passage (not shown).

[0137] In addition, when the unload lever 5c is operated to the unload position (raised position), the unload valve 58 is switched to the oil cut-off position 58b (unload position), and the hydraulic oil discharged from the control hydraulic pump P2 to the restricted oil passage 57 is discharged to the hydraulic oil tank 48 without being supplied to the operating valves PV1 to PV6, making the control valves V1 to V8 inoperable.

[0138] As a result, the supply of hydraulic oil from the actuation hydraulic pump P1 to the hydraulic actuators C1 to C5, ML, MR, and MT is prohibited (shut off), and operation of any of the hydraulic actuators is not permitted.

[0139] In this embodiment, the configuration has been described in which the unloading valve 58 is switched in response to the operation of the unloading lever 5c to switch the supply / discharge state of hydraulic oil to the operating valves PV1 to PV6, thereby switching whether or not the operating device 5 can operate the working device 20 and the traveling device 10, but the present invention is not limited to this.

[0140] For example, a solenoid valve may be provided to switch the operation of some or all of the control valves V1 to V8, and a control device that controls the operation of this solenoid valve may control the operation of the solenoid valve in accordance with the switching position of the unload lever 5c, thereby switching the working device 20 and the traveling device 10 between an operable state and an operation-prohibited state.

[0141] In addition, the working device 20 and the traveling device 10 may be configured to be operated in part or in whole by an electric actuator, and a control device that controls the operation of the electric actuator may control the operation of the electric actuator according to the switching position of the unload lever 5c, thereby switching the working device 20 and the traveling device 10 between an operable state and an operation-prohibited state.

[0142] Hereinafter, the work device 20, traveling device 10, dozer 17, etc., which are operated by the work operation lever 5a and the travel operation lever 5b of the operation device 5 (hereinafter referred to as "operation levers 5a, 5b" or simply the operation device), will be collectively referred to as the work device (regardless of whether it is hydraulic or electric, etc.).

[0143] In other words, the unlock lever 5c is an operation lock device that can be switched between an allowance position that allows operation of the work device using the operation device (operation levers 5a, 5b) and a prohibition position that prohibits operation of the work device using the operation device (operation levers 5a, 5b).

[0144] In addition to the above, the hydraulic circuit K is provided with an operation detection oil passage (not shown) for detecting the operation states of the control valves V1 to V8. The operation detection oil passage is an oil passage that returns pilot oil discharged from the control hydraulic pump P2 to the hydraulic oil tank 59, sequentially passing through a plurality of switching valves that switch the positions of the control valves V1 to V8. The AI-SW 48 (Fig. 1) is connected to this operation detection oil passage.

[0145] When any of the control valves V1 to V8 is operated from the neutral position to the switching position, a part of the operation detection oil passage is blocked, the pressure of the pilot oil in the operation detection oil passage increases to a certain extent (a so-called pressurized state), and the AI-SW 48 is turned on. That is, the AI-SW 48 detects that at least one of the hydraulic actuators C1 to C5, ML, MR, and MT is operating.

[0146] Furthermore, when the control valves V1 to V8 are all in the neutral position, the operation detection oil passages are open, so the pressure of the pilot oil in the operation detection oil passages does not increase to a certain value (a so-called no-pressure state), and the AI-SW 48 is in the off state. That is, the AI-SW 48 detects that none of the hydraulic actuators C1 to C5, ML, MR, and MT are operating.

[0147] When the unloading lever 5c is in the load position (down position), that is, when the unloading valve 58 is in the oil supply position 58a, the AI-SW 48 is in the on state as long as at least one of the hydraulic actuators C1 to C5, ML, MR, and MT is operating.

[0148] However, if a state occurs in which none of the hydraulic actuators are operating even though the unload lever 5c is in the load position (down position), and this state continues for a certain period of time, the AI-SW 48 switches to the OFF state. Based on this switching of the AI-SW 48 to the OFF state, the control device 7 issues a command to set the motor rotation speed MS of the electric motor 9 to the idle rotation speed MS3 (see Figure 5). This control of the electric motor 9 is called auto-idle control.

[0149] The work machine 1 is equipped with an electrical system and a hydraulic system having the above-described structure, and is provided with the aforementioned radiator 35 and oil cooler 37 as coolers that cool the cooling water and hydraulic oil circulating through the equipment belonging to these electrical and hydraulic systems.

[0150] Furthermore, this cooler is equipped with an electric cooling fan: the radiator 35 is equipped with a radiator fan 35a that is driven to rotate by the output of an electric fan motor 35b, and the oil cooler 37 is equipped with an oil cooler fan 37a that is driven to rotate by the output of an electric fan motor 37b.

[0151] In the case of a work machine equipped with an engine (internal combustion engine) as a prime mover, the radiator fan of the radiator attached to the engine is configured to rotate synchronously with the engine output shaft via a fan belt or the like, so in principle the radiator fan is always rotating while the engine is running. Furthermore, the rotation speed of the radiator fan also changes in synchronization with changes in engine rotation speed.

[0152] In contrast, the work machine 1 is equipped with an electric motor 9 as a prime mover, and the rotational drive of the electric cooling fans in the cooler described above, such as the radiator fan 35a, is independent of the rotational drive of the electric motor 9. The control device 7 controls the rotational drive of such electric cooling fans, the radiator fan 35a and the oil cooler fan 37a, in accordance with the temperature condition of the object to be cooled, etc.

[0153] In this way, the electric cooling fan can be controlled to stop rotation or rotate at a low speed depending on the situation, for example, to reduce noise. In the work machine 1, the radiator fan 35a and the oil cooler fan 37a are installed side by side as cooling fans, as shown in Figure 8, so reducing noise is particularly desirable.

[0154] Therefore, the work machine 1 according to this embodiment employs a control system for an electric cooling fan as shown in Figures 3, 4A, 4B, 5, 6A, 6B, and 6C. This structure will be described below.

[0155] First, the work machine 1 stores a cooling fan rotation characteristic diagram showing at least one cooling fan control pattern in a storage device such as the aforementioned memory unit 7b. The cooling fan rotation characteristic diagram is a combination of multiple fan control maps created according to individual situations. In other words, the cooling fan rotation characteristic diagram is a group of maps.

[0156] The work machine 1 according to this embodiment stores, as such map groups, a first map group MG1 shown in FIG. 3 and a second map group MG2 shown in FIG. 5 in a storage device.

[0157] Each of the map groups MG1 and MG2 consists of a plurality of fan control maps that show the characteristics of the rotation speed of the cooling fan versus the temperature of the object to be cooled (coolant, hydraulic oil, etc.). That is, the fan control map is a graph created with the temperature T of the object to be cooled (hereinafter referred to as "cooling object temperature T") as described above on the horizontal axis and the rotation speed FS of the cooling fan (hereinafter referred to as "fan rotation speed FS") on the vertical axis.

[0158] The first map group MG1 shown in Fig. 3 will now be described. The first map group MG1 includes a plurality of fan control maps M11, M12, and M13.

[0159] The fan control map M11 is selected when the unload valve 58 is in the oil shutoff position 58b or when the unload lever 5c is pulled up to the unload position (up position) (hereinafter simply referred to as "unload time").

[0160] The fan control map M12 is selected when the unload valve 58 is in the oil supply position 58a or when the unload lever 5c is lowered to the load position (lowered position) (hereinafter simply referred to as "load time").

[0161] Even during loading, when the AI-SW 48 is turned off, that is, when auto-idling control is executed, the fan control map M11 is selected.

[0162] The fan control map M13 is selected when any of the abnormally high temperature detection devices 49 individually equipped in the plurality of high-power equipment (including the electric motor 9) detects an abnormally high temperature, regardless of whether the equipment is loaded or unloaded, as described above.

[0163] The fan control map M11 selected during unloading or when auto-idling control is being executed indicates that when the cooling target temperature T is equal to or higher than temperature T11a, the fan rotation speed FS is set to fan rotation speed FS11.

[0164] Temperature T11a is set as a threshold value for determining whether to increase fan rotation speed FS from 0 to rotation speed FS11. In other words, when the cooling target temperature T rises from a state below temperature T11a and reaches temperature T11a while the cooling fan is stopped, the cooling fan starts rotating at rotation speed FS11, and while the temperature continues to rise, fan rotation speed FS is maintained at rotation speed FS11.

[0165] On the other hand, the fan control map M11 is configured such that the cooling fan is rotated at the rotation speed FS11 and the target temperature T is equal to the temperature T11a. Higher Even if the temperature T of the object to be cooled drops from the above state and reaches a temperature T11a, the rotation speed is maintained at FS11, and when the temperature T of the object to be cooled drops further to a temperature T11b, the rotation of the cooling fan is stopped.

[0166] The temperature T11b is a threshold value for determining whether to stop the rotation of the cooling fan at the rotation speed FS11 (to set the rotation speed to 0), and is a value lower than the temperature T11a.

[0167] In this way, by differentiating the temperature T11a as the threshold for starting (ON) the cooling fan and the temperature T11b as the threshold for stopping (OFF) the cooling fan, it is possible to prevent the cooling fan from overly sensitively responding to changes in the temperature T of the object to be cooled and switching on and off frequently.

[0168] During auto-idling control, the motor rotation speed MS of the electric motor 9 is the idle rotation speed MS3 (see FIG. 5). That is, the rotation speed FS11 is determined in accordance with the rotational drive of the electric motor 9 at the idle rotation speed MS3.

[0169] On the other hand, during unloading, it is conceivable to set the motor rotation speed MS of the electric motor 9 to the idle rotation speed MS3, or to set the motor rotation speed MS to 0 (that is, to stop the rotation of the electric motor 9).

[0170] The fan control map M12 selected at the time of loading, except when auto-idling control is being executed, indicates that when the temperature T to be cooled is equal to or higher than temperature T12, the fan rotation speed FS is FS12, and as temperature T rises from temperature T13a, which is lower than temperature T12, to temperature T12, the fan rotation speed FS increases from rotation speed FS11 to rotation speed FS12.

[0171] The rotation speed FS12 is determined as the rotation speed of the cooling fan that can cool the object to be cooled when the hydraulic actuator is normally operated to drive the working implement 20 and the traveling implement 10.

[0172] In the fan control map M12, the temperature T13a is set as a threshold value for determining whether to increase the fan rotation speed FS from 0 to rotation speed FS11. In other words, when the cooling target temperature T increases from a state below temperature T13a and reaches temperature T13a while the cooling fan is stopped, the cooling fan starts rotating at rotation speed FS11.

[0173] As the temperature T rises from temperature T13a to temperature T12, the fan rotation speed FS increases from rotation speed FS11 to rotation speed FS12, and is maintained at rotation speed FS12 while the temperature T to be cooled is higher than temperature T12.

[0174] The temperature T13b is a threshold value for determining whether to stop the rotation of the cooling fan at the rotation speed FS11 (to set the rotation speed to 0).

[0175] In other words, after the temperature T of the object to be cooled increases to temperature T13a and the cooling fan starts to rotate, even if the temperature T of the object to be cooled falls to temperature T13a, the cooling fan continues to rotate at rotation speed FS21 until it falls to temperature T13b, which is lower than temperature T13a.

[0176] In this way, by differentiating the temperature T13a as the threshold for starting (ON) the cooling fan and the temperature T13b as the threshold for stopping (OFF) the cooling fan, it is possible to prevent the cooling fan from overly sensitively responding to changes in temperature T and switching on and off frequently.

[0177] In this embodiment, the temperature T12 corresponding to the timing at which the fan rotation speed FS increases in response to an increase in the temperature T to be cooled and reaches rotation speed FS12 is set to be approximately equal to the temperature T11a corresponding to the timing at which the temperature T to be cooled increases and the fan rotation speed FS rises from 0 to rotation speed FS11 on the fan control map M11.

[0178] This is just one example, and the relationship between the temperature T12 on the fan control map M12 and the temperatures T11a and T11b on the fan control map M11 is not particularly limited.

[0179] The fan control map M13 is set so that the fan rotation speed FS is set to rotation speed FS13 when the abnormally high temperature detection device 49 of any of the high-power equipment detects an abnormally high temperature and the temperature T to be cooled is equal to or higher than temperature T14a. The rotation speed FS13 is a rotation speed suitable for cooling the high-power equipment that is in an abnormally high temperature state and restoring it from the abnormally high temperature state to a normal temperature state, and is higher than the rotation speed FS12.

[0180] The fan control map M13 indicates that the fan rotation speed FS is the rotation speed on the fan control map M11 or M12 when the cooling target temperature T is lower than the temperature T14a. In other words, the temperature T14a is set as a threshold value for determining whether to switch the fan control map selected for controlling the rotation drive of the cooling fan from the previously used fan control map M11 or M12 to the fan control map M13.

[0181] In addition, in the fan control map M13, a temperature T14b lower than the temperature T14a is set as a threshold value for determining whether to reduce the fan rotation speed FS from the fan rotation speed FS3 to the rotation speed on the fan control map M11 or M12.

[0182] That is, once the fan rotation speed FS has risen to rotation speed FS13, it is maintained at rotation speed FS13 until the temperature T of the object to be cooled drops to temperature T14b, which is lower than temperature T14a. This prevents the fan rotation speed FS from immediately dropping back to its original value as soon as the temperature T of the object to be cooled drops as soon as the fan rotation speed FS rises to fan rotation speed FS, thereby enabling the high-power equipment to be cooled appropriately.

[0183] In this embodiment, the temperature T14a is set to a value higher than the temperature T13a and lower than the temperature T12, and the temperature T14b is set to a value approximately equal to the temperature T13a, but this is not limitative and the values ​​may be set appropriately depending on the characteristics and cooling performance of each high-power device, etc.

[0184] Next, the control flow of the cooling fan using the first map group MG1 will be described with reference to FIGS. 4A and 4B.

[0185] 4A, it is determined whether the unloading valve 58 is in the oil supply position (loading position) 58a (loading) or in the oil cutoff position (unloading position) 58b (unloading) (step S01). This determination may be replaced by a determination of whether the unloading lever 5c is in the load position (lowered position) or the unloading position (upper position) based on the detection of the operating position of the unloading lever 5c.

[0186] If it is determined that the unloading valve 58 is in the oil shutoff position (unloading position) 58b (unloading) (step S01, NO), the control device 7 selects the fan control map M11 from the first map group MG1 stored in the memory unit 7b (step S03).

[0187] If the cooling target temperature T detected by the temperature detection device (corresponding to the water temperature detection device 46 or oil temperature detection device 47 in FIG. 1) is lower than the temperature T11a (step S04, NO), the fan rotation speed FS is set to 0 (step S05), and if the temperature T11a or higher (step S04, YES), the fan rotation speed FS is set to FS11 (step S06).

[0188] The fan rotation speed FS is set to a certain value by the control device 7 issuing a command signal to the electric actuator (fan motor 35b, 37b, etc.) for driving the cooling fan to control its output, and adjusting the fan rotation speed FS detected by the fan rotation speed detection device (fan rotation speed detection device 43, 44, etc.) to be the target value.

[0189] Once the fan rotation speed FS is increased to the rotation speed FS11, it is maintained as long as the cooling target temperature T is equal to or higher than the temperature T11b (step S07, YES), and when the temperature T becomes lower than the temperature T11b (step S07, NO), the fan rotation speed FS is set to 0 (step S05).

[0190] If it is determined that the unloading valve 58 is in the oil supply position (loading position) 58a (loading) (step S01, YES), it is further determined whether the AI-SW 48 is in the on state (auto-idling control is not being performed) or the off state (auto-idling control is being performed; no operation has been performed on the operating device 5 for a predetermined period of time or more) (step S02).

[0191] When AI-SW48 is in the OFF state (step S02, NO), the control device 7 selects the fan control map M11 from the first map group MG1 (step S03), and the rotation of the cooling fan is controlled in the same way as when the unload valve 58 is in the oil shut-off position 58b.

[0192] When the AI-SW 48 is in the ON state (step S02, YES), the control device 7 selects the fan control map M12 from the first map group MG1 (step S08).

[0193] If the cooling target temperature T detected by the temperature detection device is lower than temperature T13a (step S09, NO), the fan rotation speed FS is set to 0 (step S10). If the cooling target temperature T reaches temperature T11a (step S09, YES), the fan rotation speed FS is increased to rotation speed FS11 (step S11).

[0194] Once the fan rotation speed FS is increased to rotation speed FS11 when the cooling target temperature T reaches temperature T11a, even if the cooling target temperature T subsequently falls below temperature T13a (step S12, YES), it is maintained at rotation speed FS11 (step S11) as long as it remains at or above temperature T13b (step S13, YES). When the cooling target temperature T falls below temperature T13b (step S13, NO), the fan rotation speed FS is set to 0 (step S10).

[0195] The value of the fan rotation speed FS, which rises to rotation speed FS11 when the temperature T of the object to be cooled increases and reaches temperature T13a, is determined based on the temperature T of the object to be cooled that is detected each time.

[0196] Here, if the cooling target temperature T is a value within the range of equal to or greater than temperature T13a and less than temperature T12 (step S12, NO; step S14, NO), the cooling fan rotates at a rotation speed FS determined according to the value of temperature T. For example, by substituting the actual detected temperature T into the following formula "Equation 1," a fan rotation speed FS that is equal to or greater than rotation speed FS11 and less than rotation speed FS12 can be obtained (step S15).

[0197]

number

[0198] If the cooling target temperature T is equal to or higher than temperature T12 (step S14, YES), the fan rotation speed FS is equal to rotation speed FS12 (step S16), and this rotation speed FS12 is maintained as long as temperature T is maintained at or higher than temperature T12.

[0199] In this way, when the fan control map M11 or M12 is selected and the cooling fan is stopped or is rotating at the fan rotation speed FS determined based on the map (A), as shown in Figure 4B, the abnormally high temperature detection device 49 of each high-power device constantly checks for the presence or absence of an abnormally high temperature (step S21).

[0200] If the abnormally high temperature detection device 49 of any of the high-power equipment detects an abnormally high temperature (step S21, YES), and the cooling target temperature T detected by the temperature detection device at that time is equal to or higher than temperature T14a (step S22, YES), the fan control map M13 is selected (step S23), and the cooling fan is rotated at a high rotation speed of FS13, thereby preventing the high-power equipment from becoming abnormally high.

[0201] While the cooling object temperature T detected by the temperature detection device is equal to or higher than temperature T14b (step S25, YES), the fan continues to rotate at rotation speed FS13. When the detected cooling object temperature T drops below temperature T14b (step S25, NO), it is recognized that the high-voltage equipment has recovered from the abnormally high temperature state, and control of the cooling fan is returned to by selecting fan control map M11 or M12 according to the situation at that time (B).

[0202] As described above, by using the first map group MG1 to control the rotation drive of the electric cooling fan, the cooling fan can be stopped or rotated at the minimum rotation speed when there is no need to worry too much about the temperature rise of the object to be cooled, such as during unloading or auto-idling control.

[0203] Furthermore, even during loading, if the temperature T of the object to be cooled is low, the rotation of the cooling fan can be stopped or the rotation speed can be reduced.

[0204] As a result, noise caused by the rotation of the cooling fan can be reduced, power consumption can be reduced, and the object to be cooled can be prevented from being overcooled.

[0205] On the other hand, when the temperature of the object to be cooled is high due to the operation of a hydraulic actuator, etc., the object to be cooled can be cooled by rotating the cooling fan at a high rotation speed. In particular, when the high-voltage equipment becomes abnormally hot, the rotation speed of the cooling fan can be increased to quickly remove the high-voltage equipment from the abnormally high temperature state. This ensures a reliable cooling effect when the object to be cooled needs great cooling.

[0206] In the work machine 1, it is conceivable to use the radiator fan 35a as a cooling fan whose rotation drive is controlled using the first map group MG1 as described above. That is, it is conceivable that the cooler to which the rotation drive control of this cooling fan is applied is the radiator 35, the object to be cooled is the cooling water for cooling high-power equipment including the electric motor 9, and the temperature T of the object to be cooled is the cooling water temperature T detected by the water temperature detection device 46.

[0207] In this way, when the first map group MG1 of FIG. 3 is used for the rotation drive control of the radiator fan 35a, for example, the rotation speed FS11 may be set to 1000 rpm, the rotation speed FS12 to 2500 rpm, and the rotation speed FS13 to 3000 rpm.

[0208] In addition, the coolant temperature T11 serving as the threshold value when the rotation speed FS of the radiator fan 35a is increased from 0 to rotation speed FS11 in the fan control map M11 may be set to 70°C, the coolant temperature T13a serving as the threshold value when the rotation speed FS of the radiator fan 35a is increased from 0 to rotation speed FS11 in the fan control map M12 may be set to 60°C, the coolant temperature T12 corresponding to the timing when the rotation speed FS of the radiator fan 35a, which has increased from rotation speed FS11, reaches rotation speed FS12 in the fan control map M12 may be set to 70°C, and the coolant temperature T14a corresponding to the timing when the rotation speed FS of the radiator fan 35a is increased to rotation speed FS13 in the fan control map M13 may be set to 65°C, etc.

[0209] Next, a description will be given of the second map group MG2 shown in Fig. 5. The second map group MG2 includes a plurality of fan control maps M21, M22, M23, and M24.

[0210] During unloading (when the unloading valve 58 is in the oil shutoff position 58b), the fan control map M21 is selected.

[0211] Furthermore, even during loading (when the unloading valve 58 is in the oil supply position 58a), when the AI-SW 48 is turned off, that is, when auto-idling control is executed, the fan control map M22 is selected.

[0212] Except during auto-idling control, during loading, one of the fan control map M23 and the fan control map M24 is selected depending on the value to which the motor rotation speed MS of the electric motor 9 is set.

[0213] When the electric motor 9 is rotating at the high idle speed MS1, the fan control map M23 is selected, whereas when the electric motor 9 is rotating at the low idle speed MS2, the fan control map M24 is selected.

[0214] The fan control map M21 selected during unloading is set so that when the fan rotation speed FS is 0 and the cooling target temperature T is below temperature T21a, the fan rotation speed FS is maintained at 0, and when the cooling target temperature T rises from this state to temperature T21a, the fan rotation speed FS is set to rotation speed FS21.

[0215] Furthermore, the fan control map M21 is set so that after the cooling target temperature T increases to temperature T21a and the cooling fan starts to rotate, the cooling fan continues to rotate at the rotation speed FS21 until the cooling target temperature T drops to temperature T21b, even if the cooling target temperature T drops.

[0216] The fan control map M22 selected during loading and auto-idling control is set to maintain the fan rotation speed FS at 0 when the cooling target temperature T is below temperature T22a while the fan rotation speed FS is 0, and to change the fan rotation speed FS to rotation speed FS21 when the cooling target temperature T rises from this state to temperature T22a.

[0217] In addition, the fan control map M22 is set so that after the cooling target temperature T increases to temperature T22a and the cooling fan starts to rotate, the cooling fan continues to rotate at the rotation speed FS21 until the cooling target temperature T drops to temperature T22b, even if the cooling target temperature T drops.

[0218] The fan control map M23 selected when the electric motor 9 is rotating at high idle speed MS1 during load (hereinafter simply referred to as "high idle speed") is set so that when the cooling object temperature T rises from a state below temperature T25a and reaches temperature T25a while the cooling fan is stopped, the cooling fan starts rotating at speed FS21, and continues to rotate at speed FS21 until the cooling object temperature T reaches T24 or drops to temperature T25b.

[0219] The fan control map M23 is set so that after the cooling object temperature T rises to temperature T25a and the cooling fan starts to rotate, the cooling fan continues to rotate at rotation speed FS21 until the cooling object temperature T drops to temperature T25b, even if the cooling object temperature T drops, and the fan rotation speed is set to 0 when the cooling object temperature T drops to temperature T25b.

[0220] In addition, the fan control map M23 is set so that when the cooling target temperature T is equal to or greater than temperature T24 but less than temperature T23, the fan rotation speed increases in accordance with the increase in the cooling target temperature T, and when the cooling target temperature T is temperature T23, the fan rotation speed FS becomes rotation speed FS22.

[0221] Furthermore, the fan control map M23 is set so that when the cooling target temperature T reaches or exceeds the temperature T23, the fan rotation speed FS is maintained at the rotation speed FS22 until the cooling target temperature T rises further and reaches the temperature T26a.

[0222] The fan control map M23 is set so that when the temperature T to be cooled reaches temperature T26a at the rotation speed FS22, the fan rotation speed FS is increased to a rotation speed FS23, which is higher than the rotation speed FS22, and is maintained at this rotation speed FS23 even if the temperature T to be cooled increases further.

[0223] In addition, the fan control map M23 is set so that after the fan rotation speed FS is increased to rotation speed FS22, the fan rotation speed FS is decreased to rotation speed FS22 when the temperature T to be cooled falls to temperature T26b, which is lower than temperature T26a and higher than temperature T23.

[0224] In this embodiment, in the fan control map M22 selected during auto-idling control, temperatures T22a and T22b, which are thresholds for determining whether to set the fan rotation speed FS to 0 or FS21, are set between temperatures T23 and T24 in the fan control map M23. In other words, temperature T22a is set lower than temperature T23, and temperature T22b is set higher than temperature T24.

[0225] Furthermore, in the fan control map M21 selected during unloading, the temperature T21a, which is the threshold for determining whether to increase the fan rotation speed FS from 0 to rotation speed FS21, is set higher than the temperature T23 on the fan control map M23. In this case, the temperature T21b, which is the threshold for changing the fan rotation speed FS from rotation speed FS21 to 0, can be set to a value approximately equal to the temperature T23 on the fan control map M23.

[0226] The above is just one example, and the relationship between the temperature T23 on the fan control map M23 and the temperatures T21a and T21b on the fan control map M21 or the temperatures T22a and T22b on the fan control map M22 is not particularly limited. For example, the temperature T21a or the temperature T22a may be approximately equal to the temperature T23 on the fan control map M23.

[0227] The fan control map M24 selected when the electric motor 9 is rotating at low idle speed MS2 under load (hereinafter simply referred to as "low idle rotation") is set so that when the cooling fan is stopped and the temperature T of the object to be cooled rises from a state below temperature T25a and reaches temperature T25a, the cooling fan starts rotating at speed FS21, and continues to rotate at speed FS21 until the temperature T of the object to be cooled reaches T24 or drops to temperature T25b.

[0228] The fan control map M24 is set so that after the cooling object temperature T rises to temperature T25a and the cooling fan starts to rotate, even if the cooling object temperature T drops, the cooling fan continues to rotate at rotation speed FS21 until the cooling object temperature T drops to temperature T25b, and then the fan rotation speed is set to 0 when the cooling object temperature T drops to temperature T25b.

[0229] Furthermore, the fan control map M24 is set so that when the cooling target temperature T is equal to or greater than temperature T24 and less than temperature T23, the fan rotation speed FS increases in accordance with the rise in the cooling target temperature T, and when the cooling target temperature T is temperature T23, the fan rotation speed FS becomes rotation speed FS24. The rotation speed FS24 is set to a value lower than the above-mentioned rotation speed FS22.

[0230] The fan control map M24 is set to maintain the fan rotation speed FS at rotation speed FS21 while the cooling object temperature T rises from temperature T25a to temperature T24. Furthermore, the fan control map M24 increases the fan rotation speed FS in accordance with the rise in the cooling object temperature T when the cooling object temperature T is within the range from temperature T24 to temperature T23.

[0231] Furthermore, the fan control map M24 is set so that when the object to be cooled temperature T exceeds temperature T23, the fan rotation speed FS is maintained at rotation speed FS24 until the object to be cooled temperature T increases further and reaches temperature T26a. The fan control map M24 is also set so that when the object to be cooled temperature T increases to temperature T26a, the fan rotation speed FS is increased from rotation speed FS24 to a higher rotation speed FS25. Even if the object to be cooled temperature T increases further, the fan rotation speed FS is maintained at rotation speed FS25.

[0232] In addition, the fan control map M24 is set to maintain the fan rotation speed FS, which has been increased to rotation speed FS25, until the temperature T to be cooled drops to temperature T26b, which is lower than temperature T26a, and then to reduce the fan rotation speed FS to rotation speed FS24 when the temperature T to be cooled drops to temperature T26b.

[0233] The relationship between temperatures T23 and T24 on fan control map 24, temperatures T21a and 21b on fan control map M21, and temperatures T22a and T22b on fan control map M22 is similar to the relationship between temperatures T23 and T24 and temperatures T21a, 21b, 22a, and 22b on fan control map 23.

[0234] Next, the control flow of the cooling fan using the second map group MG1 will be described with reference to FIGS. 6A, 6B, and 6C.

[0235] 6A, it is determined whether the unloading valve 58 is in the oil supply position 58a (loading) or the oil cutoff position 58b (unloading) (step S31). This determination may be replaced by a determination of whether the unloading lever 5c is in the load position (lowered position) or the unloading position (upper position) based on the detection of the operating position of the unloading lever 5c.

[0236] If it is determined that the unloading valve 58 is in the oil shutoff position 58b (unloading) (step S31, NO), as shown in FIG. 6B, the control device 7 selects the fan control map M21 from the second map group MG2 stored in the memory unit 7b (step S51).

[0237] If the cooling target temperature T detected by the temperature detection device (corresponding to the water temperature detection device 46 or oil temperature detection device 47 in FIG. 1) is lower than the temperature T21a (step S52, NO), the fan rotation speed FS is set to 0 (step S53), and if the temperature T is equal to or higher than the temperature T21a (step S52, YES), the fan rotation speed FS is set to the rotation speed FS21 (step S54).

[0238] Once the fan rotation speed FS is increased to the rotation speed FS21, it is maintained as long as the cooling target temperature T is equal to or higher than the temperature T21b (step S55, YES), and when the cooling target temperature T becomes lower than the temperature T21b (step S55, NO), the fan rotation speed FS is set to 0 (step S53).

[0239] As shown in FIG. 6A, if it is determined that the unloading valve 58 is in the oil supply position 58a (loading) (step S31, YES), it is further determined whether the AI-SW 48 is in the ON state (a state in which auto-idling control is not being performed) or the OFF state (a state in which auto-idling control is being performed; a state in which the operating device 5 (operating levers 5a, 5b) has not been operated for a predetermined period of time or longer) (step S32).

[0240] When AI-SW48 is in the OFF state (step S32, NO), as shown in FIG. 6B, the control device 7 selects the fan control map M22 from the second map group MG1 (step S61) and controls the rotational drive of the cooling fan based on the fan control map M22.

[0241] If the cooling target temperature T detected by the temperature detection device is lower than the temperature T22a (step S62, NO), the fan rotation speed FS is set to 0 (step S63), and if it is equal to or higher than the temperature T21a (step S62, YES), the fan rotation speed FS is set to FS21 (step S64).

[0242] Once the fan rotation speed FS is increased to the rotation speed FS21, it is maintained as long as the cooling target temperature T is equal to or higher than the temperature T22b (step S65, NO), and when the cooling target temperature T becomes lower than the temperature T22b (step S65, YES), the fan rotation speed FS is set to 0 (step S63).

[0243] When the AI-SW48 is in the ON state (step S32, YES), it is determined whether the normal mode (electric motor 9 is rotated at high idle speed MS1) or the ECO mode (electric motor 9 is rotated at low idle speed MS2) is selected by the mode selection SW5e (step S33).

[0244] Instead of determining the mode selection (step S33), it may be determined whether the motor rotation speed MS of the electric motor 9 detected by the motor rotation speed detection device 42 is the high idle rotation speed MS1 or the low idle rotation speed MS2.

[0245] If the normal mode is selected (the motor rotation speed MS is the high idle rotation speed MS1) (step S33, YES), the control device 7 selects the fan control map M23 from the second map group MG2 (step S34).

[0246] If the cooling object temperature T detected by the temperature detection device is lower than temperature T25a (step S35, NO), the fan rotation speed FS is set to 0 (step S36). When the cooling object temperature T reaches temperature T25a (step S35, YES), the fan rotation speed FS is increased to rotation speed FS21, and remains at this speed until the cooling object temperature T reaches temperature T24 (step S37, NO) (step S38).

[0247] Once the fan rotation speed FS is increased to rotation speed FS21 when the temperature T of the object to be cooled reaches temperature T25a, it is maintained at rotation speed FS21 (step S38) as long as the temperature T is equal to or higher than temperature T25b (step S39, YES), even if the temperature T of the object to be cooled subsequently drops, and when temperature T becomes less than temperature T25b (step S39, NO), the fan rotation speed FS is set to 0 (step S36).

[0248] If the cooling target temperature T is a value within the range of equal to or greater than temperature T24 and less than temperature T23 (step S37, YES; step S40, NO), the cooling fan rotates at a rotation speed FS determined according to the value of temperature T. For example, the fan rotation speed FS can be obtained by substituting the actual detected temperature T into the following formula "Equation 2" (step S41).

[0249]

number

[0250] If the cooling target temperature T is equal to or higher than the temperature T23 (step S40, YES) but lower than the temperature T26a (step S43, NO), the fan rotation speed FS is set to the rotation speed FS22 (step S44).

[0251] When the temperature T to be cooled becomes equal to or higher than the temperature T26a (step S43, YES), the fan rotation speed FS is increased to the rotation speed FS23 (step S44).

[0252] Once the cooling target temperature T reaches temperature T26a, the fan rotation speed FS is increased to rotation speed FS23. Even if the cooling target temperature T subsequently drops, the fan rotation speed FS is maintained at rotation speed FS23 (step S44) as long as the temperature remains equal to or higher than temperature T26b (step S45, YES). When temperature T falls below temperature T26b (step S45, YES), the fan rotation speed FS is increased to rotation speed FS22 (step S42).

[0253] When the engine is loaded (step S31, YES), the AI-SW48 is on (step S32, YES), and the ECO mode is selected by operating the mode selection SW7e, that is, when the motor rotation speed MS of the electric motor 9 is the low idle rotation speed MS2 (step S33, NO), as shown in FIG. 6C, the control device 7 selects the fan control map M24 from the second map group MG2 (step S71).

[0254] If the cooling object temperature T detected by the temperature detection device is lower than temperature T25a (step S72, NO), the fan rotation speed FS is set to 0 (step S73). When the cooling object temperature T reaches temperature T25a (step S72, YES), the fan rotation speed FS is increased to rotation speed FS21, and remains at this speed until the cooling object temperature T reaches temperature T24 (step S74, NO) (step S75).

[0255] Once the fan rotation speed FS is increased to rotation speed FS21 when the temperature T of the object to be cooled reaches temperature T25a, the fan rotation speed FS is maintained at rotation speed FS21 (step S75) as long as the temperature T is equal to or higher than temperature T25b (step S76, YES), even if the temperature T of the object to be cooled subsequently drops, and when temperature T becomes less than temperature T25b (step S76, NO), the fan rotation speed FS is set to 0 (step S73).

[0256] If the cooling target temperature T is a value within the range of equal to or greater than temperature T24 and less than temperature T23 (step S74, YES; step S77, NO), the cooling fan rotates at a rotation speed FS determined according to the value of temperature T. For example, the fan rotation speed FS can be obtained by substituting the actual detected temperature T into the following formula "Equation 3" (step S78).

[0257]

number

[0258] If the temperature T to be cooled is equal to or higher than the temperature T23 (step S77, YES) and is lower than the temperature T26a (step S 80 , NO), and the fan rotation speed FS is FS24 (step S79).

[0259] When the temperature T to be cooled becomes equal to or higher than the temperature T26a (step S80, YES), the fan rotation speed FS is increased to the rotation speed FS25 (step S81).

[0260] Once the cooling target temperature T reaches temperature T26a, the fan rotation speed FS is increased to rotation speed FS25. Even if the cooling target temperature T subsequently drops, the fan rotation speed FS is maintained at rotation speed FS25 (step S81) as long as the cooling target temperature T remains equal to or higher than temperature T26b (step S82, YES). When the cooling target temperature T falls below temperature T26b (step S82, YES), the fan rotation speed FS is set to rotation speed FS24 (step S79).

[0261] As described above, by using the second map group MG2 to control the rotation drive of the electric cooling fan, the cooling fan can be stopped or rotated at the minimum rotation speed when there is no need to worry too much about the temperature rise of the object to be cooled, such as when unloading or during auto-idling control.

[0262] Even when the engine is under load, if the temperature of the object to be cooled is low, the cooling fan can be stopped or its rotation speed can be reduced. Furthermore, even if the temperature of the object to be cooled is high, the cooling fan's rotation speed can be reduced during low idle rotation.

[0263] As a result, noise caused by the rotation of the cooling fan can be reduced, power consumption can be reduced, and the object to be cooled can be prevented from being overcooled.

[0264] On the other hand, when the temperature of the object to be cooled is high due to the operation of a hydraulic actuator, etc., the object to be cooled can be cooled by rotating the cooling fan at a high rotation speed. In particular, when the temperature of the object to be cooled is extremely high, the rotation speed of the cooling fan can be increased both during high idle and low idle, so that the object to be cooled can be quickly removed from an abnormally high temperature state, and a reliable cooling effect can be achieved.

[0265] In the work machine 1, it is conceivable to use the oil cooler fan 37a as a cooling fan whose rotation drive is controlled using the second map group MG1 as described above. That is, it is conceivable that the cooler to which the rotation drive control of this cooling fan is applied is the oil cooler 37, the object to be cooled is the hydraulic oil discharged from the hydraulic pumps P1, P2 driven by the electric motor 9 toward the hydraulic actuator, and the temperature T of the object to be cooled is the hydraulic oil temperature T detected by the oil temperature detection device 47.

[0266] In this way, when the second map group MG1 of Figure 5 is used for rotation drive control of the oil cooler fan 37a, it is possible to set, for example, the rotation speed FS21 to 1000 rpm, the rotation speed FS22 to 3000 rpm, the rotation speed FS23 to 3500 rpm, the rotation speed FS24 to 1500 rpm, and the rotation speed FS25 to 2000 rpm.

[0267] In addition, the hydraulic oil temperature T21a as a threshold value when increasing the rotation speed FS of the oil cooler fan 37a from 0 to the rotation speed FS21 in the fan control map M21 is set to 90°C, the hydraulic oil temperature T22a as a threshold value when increasing the rotation speed FS of the oil cooler fan 37a from 0 to the rotation speed FS21 in the fan control map M22 is set to 80°C, and the threshold value when increasing the rotation speed FS of the oil cooler fan 37a from 0 to the rotation speed FS21 in the fan control maps M23 and M24 is set to It is conceivable to set the hydraulic oil temperature T25a as 60°C, set the temperature T23 corresponding to the timing when the rotation speed FS of the oil cooler fan 37a, which has increased from the rotation speed FS21 in the fan control maps M23 and M24, reaches the rotation speed FS22 and FS24 as 85°C, and set the temperature T26a corresponding to the timing when the rotation speed FS of the oil cooler fan 37a is increased from the rotation speed FS22 and FS24 to the rotation speed FS23 and FS25 in the fan control maps M23 and M24 as 100°C.

[0268] Note that changes in the rotation speed of the electric motor 9 lead to changes in the discharge flow rate of the hydraulic pumps P1 and P2, which in turn result in changes in the temperature of the hydraulic oil. Therefore, for the control of the oil cooler fan 37a, it is effective to employ a second map group MG2 that provides multiple fan control maps M22 and M24 according to differences in the rotation speed of the electric motor 9.

[0269] In contrast, the absorption torque of the hydraulic pumps P1 and P2 is constant regardless of changes in the rotation speed of the electric motor 9, so the amount of heat generated by the electric motor 9 itself does not change much whether the motor is rotating at a low speed or a high speed. Therefore, the coolant temperature T of the radiator 35, which cools the coolant that cools electrical equipment such as the electric motor 9, is not affected as greatly by changes in the rotation speed of the electric motor 9 as by the hydraulic pumps P1 and P2. For this reason, in this embodiment, the first map group MG1, which provides a fan control map M12 created without taking into account differences in the rotation speed of the electric motor 9, is used to control the radiator fan 35a.

[0270] However, the above is an example of application of a cooling fan, and even when controlling the radiator fan 35a, if there is a situation where changes in the rotation speed of the electric motor 9 must be taken into consideration, it is possible to adopt a system that provides multiple fan control maps according to differences in the motor rotation speed MS, such as the second map group MG2, or even when controlling the oil cooler fan 37a, if only one rotation speed is set for the electric motor 9, it is possible to adopt a system that provides a uniform fan control map without taking changes in the motor rotation speed MS into consideration, such as the first map group MG1.

[0271] In this way, the control device 7 in the work machine 1 according to this embodiment selects one of a plurality of fan control maps that show the characteristics of the fan rotation speed FS relative to the temperature T to be cooled depending on whether the work machine 1 is loaded or unloaded, and in each case, the characteristics of the fan rotation speed that emerge from the control of the cooling fan are different. However, this is the minimum control that the control device 7 according to this embodiment must perform, and there are no other limitations.

[0272] For example, the cooling fan to be controlled may be one other than the radiator fan 35a or the oil cooler fan 37a. Furthermore, even if the first map group MG1 is basically used, some of the features found in the second map group MG2 may be adopted, for example, by providing a map during auto-idling control that is different from the fan control map M11 used during unloading. Alternatively, conversely, even if the second map group MG2 is basically used, some of the features found in the first map group MG1 may be adopted, for example, by adding a map such as a fan control map M13 for emergency cooling.

[0273] As described above, the work machine 1 includes an electric motor 9, a work device driven using the power of the electric motor 9, an operating device 5 (operating levers 5a, 5b) for operating the work device, an operating lock device (unload lever 5c), a cooler (radiator 35, oil cooler 37) having electric cooling fans (radiator fan 35a, oil cooler fan 37a), temperature detection devices (water temperature detection device 46, oil temperature detection device 47) for detecting a cooling object temperature T, which is the temperature of the cooling object (cooling water, hydraulic oil) cooled by the cooler (radiator 35, oil cooler 37), and a control device 7 for controlling the fan rotation speed FS, which is the rotation speed of the cooling fan (radiator fan 35a, oil cooler fan 37a), in accordance with the cooling object temperature (cooling water, hydraulic oil) detected by the temperature detection devices (water temperature detection device 46, oil temperature detection device 47). The operation lock device (unload lever 5c) can be switched between an allowance position (load position) that allows operation of the working device by the operation device 5 (operation levers 5a, 5b) and a prohibition position (unload position) that prohibits operation of the working device by the operation device 5 (operation levers 5a, 5b). The control device 7 changes the characteristics of the fan rotation speed FS relative to the cooling target temperature T depending on whether the operation lock device (unload lever 5c) is in the allowance position (load position) or the prohibition position (unload position).

[0274] With the above configuration, the control of the rotation drive of the cooling fans (radiator fan 35a, oil cooler fan 37a) can be changed depending on the cooling object temperature T, depending on whether the operation lock device (unload lever 5c) is in the permitting position (loading position) or the prohibiting position (unloading position), thereby enabling the cooling fans (radiator fan 35a, oil cooler fan 37a) to rotate in a suitable state in each case. Therefore, even in a situation where the cooling object temperature T requires the cooling fans (radiator fan 35a, oil cooler fan 37a) to rotate at high speed when the operation lock device (unload lever 5c) is in the permitting position (loading position), the rotation of the cooling fans (radiator fan 35a, oil cooler fan 37a) can be stopped or rotated at a low speed when the operation lock device (unload lever 5c) is in the prohibiting position (unloading position), thereby achieving suitable noise reduction, power consumption reduction, and prevention of overcooling.

[0275] The work machine 1 also includes a storage device (storage unit 7b) that stores a plurality of fan control maps M11, M12, M13, M21, M22, M23, and M24 that indicate the characteristics of the fan rotation speed FS relative to the temperature T to be cooled. The plurality of fan control maps include first maps M11, M21 and second maps M12, M23 that are different from one another. The control device 7 controls the rotational drive of the cooling fans (radiator fan 35a, oil cooler fan 37a) based on the first maps M11, M21 when the operation lock device (unload lever 5c) is in the prohibition position (unload position), and controls the rotational drive of the cooling fans (radiator fan 35a, oil cooler fan 37a) based on the second maps M12, M23 when the operation lock device (unload lever 5c) is in the permission position (load position).

[0276] In this way, by storing multiple fan control maps, it is possible to realize a variety of fan rotation speed characteristics equal to the number of maps, and fine-tune the rotation drive of the cooling fan according to the temperature status of the object to be cooled, etc. By storing different first maps M11, M21 and second maps M12, M23 depending on whether the operation lock device (unload lever 5c) is in the permitted position (load position) or the prohibited position (unload position), and using these to control the rotation drive of the cooling fan, it is possible to realize different fan rotation speed characteristics in each case.

[0277] The first maps M11 and M21 are set so that the fan rotation speed FS is switched between 0 and a predetermined first fan rotation speed FS11 or FS21 depending on the temperature T to be cooled.

[0278] As a result, when the operation lock device (unload lever 5c) is in the prohibition position (unload position) (during unloading), the rotation of the cooling fans (radiator fan 35a, oil cooler fan 37a) stops, preventing noise caused by fan rotation and suppressing overcooling. Furthermore, the cooling fans are rotated only when the target temperature T for cooling reaches a high temperature equal to or higher than the first temperatures T11a, T21a, and cooling becomes necessary. Even in this case, the first fan rotation speeds FS11, FS21 can be set to low values, allowing the cooling fans to rotate at low speeds, thereby reducing noise.

[0279] Furthermore, the first maps M11, M21 are configured to switch the fan rotation speed FS to the first fan rotation speed FS11 when the value of the cooling target temperature T rises from a value less than the predetermined first rotation rise temperatures T11a, T21a to the first rotation rise temperatures T11a, T21a while the fan rotation speed FS is 0, and to switch the fan rotation speed FS to 0 when the value of the cooling target temperature T falls to the predetermined first rotation drop temperatures T11b, T21b that are lower than the first rotation rise temperatures T11a, T21a while the fan rotation speed FS is the first fan rotation speed FS11.

[0280] In this way, by setting the first rotation drop temperatures T11b, T21b for stopping (OFF) the cooling fan rotation lower than the first rotation start temperatures T11a, T21a for starting (ON) the cooling fan rotation, it is possible to prevent the cooling fan from overly sensitively responding to changes in the temperature T of the object to be cooled and switching ON / OFF frequently.

[0281] Further, the second maps M12, M23, and M25 set the fan rotation speed FS to a value greater than 0 when the value of the cooling target temperature T rises from a value less than the predetermined second rotation start temperatures T13a and T25a to the second rotation start temperatures T13a and T25a in a state where the fan rotation speed FS is 0, and set the fan rotation speed FS to a value greater than 0 when the value of the cooling target temperature T is equal to or greater than the first specified temperatures T12 and T23 that are set to temperatures higher than the second rotation start temperatures T13a and T25a. S24, and when the value of the cooling target temperature T is equal to or higher than the second rotation rise temperatures T13a, T25a and lower than the first specified temperatures T12, T23, the fan rotation speed FS is set higher as the cooling target temperature T is higher within the range of lower than the second fan rotation speeds FS12, FS23, and when the value of the cooling target temperature T falls to a predetermined second rotation fall temperature T13b, T25b lower than the second rotation rise temperatures T13a, T25a while the fan rotation speed FS is not 0, the fan rotation speed FS is reduced to 0.

[0282] As a result, when the operation lock device (unload lever 5c) is in the permitted position (load position) (loading), in the range of the cooling target temperature T expected during normal operation of the work tool, a reliable cooling effect can be achieved by setting the cooling fan rotation speed to the second fan rotation speed FS12, FS22, or FS24. On the other hand, when the cooling target temperature T is low, the rotation speed can be reduced to reduce noise. Also, in the transitional range of the cooling target temperature T from low to high, the fan rotation speed FS is (gradually) increased to the second fan rotation speed FS12, FS22, or FS24 as the temperature rises. This ensures a cooling effect commensurate with the temperature condition, while preventing abrupt changes in the fan rotation speed FS, thereby eliminating abrupt changes in the noise condition (such as the occurrence of a sudden loud noise).

[0283] In addition, the second maps M12, M23, M25 are configured to set the fan rotation speed FS to a constant value FS11, FS21 lower than the second fan rotation speed FS12, FS22, FS24 when the value of the cooling target temperature T is equal to or higher than the second rotation start temperatures T13a, T25a and lower than the second specified temperatures T13a, T24, which are set to values ​​lower than the first specified temperatures T12, T23, and to set the fan rotation speed FS higher as the cooling target temperature T increases within the range of less than the second fan rotation speed FS12, FS22, FS24 when the value of the cooling target temperature T is equal to or higher than the second specified temperatures T13a, T24 and lower than the first specified temperatures T12, T23.

[0284] As a result, the cooling fan is stopped until the temperature T of the object to be cooled rises to the second specified temperature T13a or T24, preventing noise and overcooling. After the temperature T of the object to be cooled reaches the second specified temperature T13a or T24 and the cooling fan starts rotating, the cooling fan maintains constant fan rotation speeds FS11 or FS21 until the temperature T of the object to be cooled falls to the third specified temperature T13b or T25b. After the temperature T of the object to be cooled falls below the third specified temperature T13b, T25b or T25b and the cooling fan stops rotating, the cooling fan remains stopped until the temperature T of the object to be cooled rises to the second specified temperature T13a. This prevents the cooling fan from overly sensitively responding to changes in the temperature T of the object to be cooled and switching on and off frequently.

[0285] The plurality of fan control maps also include third maps M11 and M22. When the operation lock device (unlock lever 7c) is in the permitted position (load position) and the operation device 5 (work operation lever 5a, travel operation lever 5b) has not been operated for a predetermined time, the control device 7 sets the rotation speed MS of the electric motor 9 to the idle rotation speed MS3 and controls the cooling fan based on the third maps M11 and M22. The third maps M11, M22 are configured to switch the fan rotation speed FS to a predetermined auto-idle rotation speed FS11, FS21 when the value of the cooling target temperature T rises from a value less than a predetermined third rise temperature T11a, T22a to the third rotation rise temperature T11a, T22a while the fan rotation speed FS is 0, and to switch the fan rotation speed FS to 0 when the value of the cooling target temperature T falls to a predetermined third rotation drop temperature T11b, T22b that is lower than the third rotation rise temperature T11a, T22a while the fan rotation speed FS is the auto-idle rotation speed FS11, FS21.

[0286] This makes it possible to realize cooling fan rotation characteristics that are different from those of the second map, which is designed with at least the large second fan rotation speeds FS12, FS23, and FS24 in mind, and therefore makes it possible to realize cooling fan rotation characteristics that are adapted to situations where the cooling target does not require much cooling because the working device is not operating while auto idling control is being executed.

[0287] Moreover, the third map M11 is common to the first map M11.

[0288] As a result, even when the operation lock device (unlock lever 7c) is in the permitted position (load position) (loaded), during auto idling control, the cooling fan rotation characteristics can be achieved that are the same as when the operation lock device (unlock lever 7c) is in the prohibited position (unload position) (unloaded), and the same effects as when unloaded, such as reduced noise and prevention of overcooling, can be achieved.

[0289] Furthermore, the object to be cooled by the cooler (radiator 35, oil cooler 37) is a refrigerant for cooling equipment to be cooled (electric motor 9, etc.) mounted on the work machine 1, and the work machine 1 is equipped with an abnormally high temperature detection device 49 that detects an abnormally high temperature of the equipment to be cooled (electric motor 9, etc.). When the abnormally high temperature detection device 49 detects an abnormally high temperature and the temperature T of the object to be cooled is equal to or higher than a third specified temperature T14a that is set to a value equal to or higher than the second rotation start temperature T13a, the control device 7 rotates the cooling fan at a third fan rotation speed FS13 that is higher than the second fan rotation speed FS12.

[0290] As a result, even when the cooling fan rotation speed is controlled according to the temperature conditions during loading, if an abnormally high temperature is detected in the equipment to be cooled, such as the electric motor 9, which is a high-power equipment, cooling of that equipment is given priority, and the cooling fan is rotated at the third fan rotation speed FS13, which is higher than the second fan rotation speed FS12, to quickly and powerfully cool the refrigerant, thereby preventing failure of the equipment to be cooled.

[0291] In addition, when the value of the cooling target temperature T drops to a fourth specified temperature T14b that is lower than the third specified temperature T14a while the cooling fan is rotating at the third fan rotation speed FS13, the control device 7 returns the control of the cooling fan rotation speed to control based on the second map M12.

[0292] This prevents the temperature T of the object to be cooled from dropping as soon as the fan rotation speed FS rises to the third fan rotation speed FS13 and then immediately dropping back to the original rotation speed, and ensures that the rotation of the cooling fan at the third fan rotation speed FS13 provides a sufficient and reliable cooling effect for the equipment to be cooled (electric motor 9, etc.).

[0293] Furthermore, the second maps M23, M24 are configured to set the fan rotation speed FS to a fourth fan rotation speed FS23, FS25 that is higher than the second fan rotation speed FS22, FS24 when the value of the cooling target temperature T rises to a fourth rotation rise temperature T26a that is higher than the first specified temperature T23 while the fan rotation speed FS is the second fan rotation speed FS22, FS24, and to reduce the fan rotation speed FS to the second fan rotation speed FS22, FS24 when the value of the cooling target temperature T falls to a predetermined fourth rotation fall temperature T26b that is lower than the fourth rotation rise temperature T26a and higher than the first specified temperature T23 while the fan rotation speed FS is the fourth fan rotation speed FS23, FS25.

[0294] As a result, when the temperature T of the object to be cooled reaches a very high level equal to or higher than the fourth rotation start temperature T26a, the fan rotation speed FS is immediately increased to the fourth fan rotation speed F23, F25, i.e., by increasing the rotation speed of the cooling fan, the object to be cooled can be quickly removed from this high temperature state. This also prevents the temperature T of the object to be cooled from dropping as soon as the fan rotation speed FS rises to the fourth fan rotation speed FS and then immediately returning to its original rotation speed, ensuring a sufficient and reliable cooling effect for the object to be cooled that is in a high temperature state.

[0295] The plurality of fan control maps also includes a fourth map M24. The fourth map M24 is configured to set the fan rotation speed FS to a value greater than 0 when the cooling target temperature T rises from a value less than the second rotation start temperature T25a to the second rotation start temperature T25a while the fan rotation speed FS is 0, to set the fan rotation speed FS to a predetermined fifth fan rotation speed FS24 lower than the second fan rotation speed FS22 when the cooling target temperature T is equal to or greater than the first specified temperature T23, to set the fan rotation speed FS to a higher value as the cooling target temperature T increases within a range less than the fifth fan rotation speed FS24 when the cooling target temperature T is equal to or greater than the second rotation start temperature T25a but less than the first specified temperature T23, and to reduce the fan rotation speed FS to 0 when the cooling target temperature T falls to the second rotation drop temperature T25b while the fan rotation speed FS is not 0. The control device 7 controls the cooling fan based on the second map M23 when the rotation speed MS of the electric motor 9 is set to a high value MS1, and controls the cooling fan based on the fourth map M24 when the rotation speed MS of the electric motor 9 is set to a low value MS2.

[0296] As a result, by differentiating the characteristics of the fan rotation speed FS relative to the object to be cooled temperature T when the electric motor 9 is rotating at high rotation speed MS1 (hereinafter simply referred to as "when the motor is rotating") from when the motor is rotating at low rotation speed MS2, it is possible to realize cooling fan rotation characteristics that match the temperature conditions of the object to be cooled that occur when the motor is rotating at each motor rotation speed. That is, in accordance with the temperature conditions of the object to be cooled when the motor is rotating at low rotation speed MS2, the fourth map M24 employs rotation characteristics that cause the fan rotation speed FS to stay at a small value as the object to be cooled temperature T increases. This makes it possible to keep the fan rotation speed FS low, thereby achieving effects such as reduced noise and reduced power consumption.

[0297] Furthermore, the fourth map M24 is configured to set the fan rotation speed FS to a sixth fan rotation speed FS25 that is greater than the fifth fan rotation speed FS24 when the value of the cooling target temperature T rises to a fourth rotation rise temperature T26a that is higher than the first specified temperature T23 while the fan rotation speed FS is at the fifth fan rotation speed FS24, and to reduce the fan rotation speed FS to the fifth fan rotation speed FS24 when the value of the cooling target temperature T falls to a predetermined fourth rotation fall temperature T26b that is lower than the fourth rotation rise temperature T26a and higher than the first specified temperature T23 while the fan rotation speed FS is at the sixth fan rotation speed FS25.

[0298] As a result, when the temperature T of the object to be cooled rises to a very high temperature range above the fourth rotation start temperature T26a, the cooling fan speed immediately rises to the sixth fan rotation speed FS25, allowing the object to be cooled to quickly escape from this high temperature state. This also prevents the temperature T of the object to be cooled from dropping immediately after rising to the sixth fan rotation speed FS25 and then immediately returning to the original fifth fan rotation speed FS24, ensuring a sufficient and reliable cooling effect for the high-voltage equipment when the cooling fan rotates at the sixth fan rotation speed FS25.

[0299] The cooler is a radiator 35 for cooling the cooling water that cools the equipment including the electric motor 9, the cooling fan is a radiator fan 35a provided in the radiator 35, and the temperature detection device detects the temperature of the cooling water as the temperature T to be cooled.

[0300] As a result, the radiator fan 35a of the radiator 35 for cooling the coolant that cools the devices including the electric motor 9 can take advantage of being an electric fan to optimize the characteristics of the fan rotation speed FS of the radiator fan 35a relative to the coolant temperature T, which is the target for control, depending on whether the vehicle is under load or unload. Therefore, for example, under unload, the rotation of the radiator fan 35a is stopped or rotated at the first fan rotation speed FS11 (low speed), which has the effects of reducing noise caused by the high-speed rotation of the radiator fan 35a, reducing power consumption, and preventing overcooling.

[0301] Furthermore, by controlling the rotation speed of the radiator fan 35a based on the detection of an abnormally high temperature by the abnormally high temperature detection device 49, even when the rotation speed of the radiator fan 35a is controlled according to the temperature conditions during loading, if an abnormally high temperature is detected in the equipment to be cooled, such as the electric motor 9, which is a high-power equipment, cooling of that equipment is given priority, and the radiator fan 35a is rotated at the third fan rotation speed FS13, which is higher than the second fan rotation speed FS12, to quickly and powerfully cool the coolant, which is a refrigerant, thereby preventing failure of the equipment to be cooled, including the electric motor 9.

[0302] The work machine 1 also includes hydraulic pumps P1 and P2 driven by an electric motor 9, and hydraulic actuators C1 to C5, ML, MR, and MT driven by the hydraulic pressure of the hydraulic oil discharged by the hydraulic pumps P1 and P2. The cooler is an oil cooler 37 for cooling the hydraulic oil, the cooling fan is an oil cooler fan 37a provided in the oil cooler 37, and the temperature detection device detects the temperature of the hydraulic oil as the temperature T to be cooled.

[0303] As a result, the oil cooler fan 37a of the oil cooler 37, which cools the hydraulic oil discharged from the hydraulic pumps P1 and P2 and supplied to the hydraulic actuators C1 to C5, ML, MR, and MT, can take advantage of being an electric fan to optimize the characteristics of the fan rotation speed FS of the oil cooler fan 37a relative to the hydraulic oil temperature T, which is the target for control, depending on whether the engine is loaded or unloaded. Therefore, for example, when the engine is unloaded, the oil cooler fan 37a can be stopped or rotated at the first fan rotation speed FS11 (low speed), which has the effects of reducing noise caused by the high-speed rotation of the oil cooler fan 37a, reducing power consumption, and preventing overcooling.

[0304] Furthermore, by selecting either the second map M23 or the fourth map M24 in accordance with the setting of the rotation speed MS of the electric motor 9 to control the rotation speed of the oil cooler fan 37a, it is possible to realize rotation characteristics of the oil cooler fan 37a that match the temperature conditions of the hydraulic oil that occur when the motor rotates at each motor rotation speed. That is, the fourth map M24 employs rotation characteristics in which the fan rotation speed FS remains small as the temperature T of the object to be cooled increases, in accordance with the temperature conditions of the object to be cooled when the motor rotates at the low rotation speed MS2. This makes it possible to keep the fan rotation speed FS low, thereby achieving effects such as reduced noise and reduced power consumption.

[0305] The work machine 1 also includes hydraulic pumps P1 and P2 driven by the electric motor 9, and hydraulic actuators C1 to C5, ML, MR, and MT driven by the hydraulic pressure of the hydraulic oil discharged by the hydraulic pumps P1 and P2, and includes, as coolers, a radiator 35 for cooling the cooling water that cools devices including the electric motor 9, and an oil cooler 37 for cooling the hydraulic oil, and, as cooling fans, a radiator fan 35a provided in the radiator 35 and an oil cooler fan 37a provided in the oil cooler 37. Temperature detection devices (water temperature detection device 46, oil temperature detection device 47) detect the temperature of the cooling water and the temperature of the hydraulic oil as the temperature T to be cooled. The storage device (storage unit 7b) stores a plurality of fan control maps M11, M12, M13 for the radiator fan 35a, each showing a characteristic of the rotation speed FS of the radiator fan 35a relative to the coolant temperature T, and a plurality of fan control maps M21, M22, M23, M24 for the oil cooler fan 37a, each showing a characteristic of the rotation speed FS of the oil cooler fan 37a relative to the hydraulic oil temperature T. The control device 7 controls the rotation speed FS of the radiator fan 35a based on the plurality of fan control maps M11, M12, M13 for the radiator fan 35a, and controls the rotation speed FS of the oil cooler fan 37a based on the plurality of fan control maps M21, M22, M23, M24 for the oil cooler fan 37a.

[0306] This makes it possible to achieve optimal rotation control according to the function of each cooling fan and the expected temperature conditions in a work machine 1 equipped with two cooling fans, the radiator fan 35a and the oil cooler fan 37a. In particular, in a structure in which these two cooling fans are arranged side by side, the problem of noise is more serious than when there is only one cooling fan, and this system can provide a reliable noise reduction effect for such a structure.

[0307] In the above embodiment, an example has been described in which the present invention is applied to a work machine 1 such as a backhoe, but the application of the present invention is not limited to this, and the present invention may be applied to other construction machines such as wheel loaders, compact track loaders, and skid steer loaders, or agricultural machines such as tractors, combine harvesters, rice transplanters, and lawn mowers.

[0308] Although the present invention has been described above, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0309] 1 Work equipment 5 Operating device 5c Unload lever (operation lock device) 5e Mode selection switch (mode selection switch) 7 Control Device 9 Electric motor 10 Traveling equipment (working equipment) 17 Dozer (working equipment) 20 Work equipment 30 Battery Unit 35 Radiator (cooler) 35a Radiator fan (cooling fan) 37 Oil cooler (cooler) 37a Oil cooler fan (cooling fan) 42 Motor rotation speed detection device 43 Fan rotation speed detection device 44 Fan rotation speed detector 46 Water temperature detector (temperature detector) 47 Oil temperature detector (temperature detector) 48 AI-SW (idling switch) 49 Abnormally high temperature detection device 58 Unloading valve 58a Oil supply position (load position) (allowed position) 58b Oil shutoff position (unload position) (prohibited position) C1~C5 Hydraulic cylinders (hydraulic actuators) ML, MR, MT hydraulic motor (hydraulic actuator) P1, P2 hydraulic pumps MG1 1st map group M11 Fan Control Map (1st Map) M12 Fan Control Map (2nd Map) M13 Fan Control Map MG2 2nd map group M21 Fan Control Map (1st Map) M22 Fan Control Map (3rd Map) M23 Fan Control Map (2nd Map) M24 Fan Control Map (4th Map) FS Fan Speed FS11 1st fan rotation speed FS12 2nd fan speed FS13 3rd fan rotation speed FS21 1st fan rotation speed FS22 2nd fan speed FS23 4th fan rotation speed FS24 5th fan rotation speed FS25 6th fan rotation speed MS Motor rotation speed MS1 High idle speed (1st motor speed) MS2 Low idle speed (second motor speed) MS3 idle speed T Cooling target temperature (water temperature, oil temperature) T11a First rotation start temperature T11b First rotational descent temperature T12 1st specified temperature T13a Second rotation start temperature (second specified temperature) T13b Second rotational descent temperature T14a 3rd specified temperature T14b 4th specified temperature T21a First rotation start temperature T21b First rotational descent temperature T22a 3rd rotation start temperature T22b Third rotational descent temperature T23 1st specified temperature T24 2nd specified temperature T25a Second rotation start temperature T25b Second rotational descent temperature T26a 4th rotation start temperature T26b 4th rotational descent temperature

Claims

1. An electric motor; a working device driven by power of the electric motor; an operating device for operating the working device; an operation lock device that is switchable between an enabling position that enables operation of the working device by the operating device and a disabling position that disables operation of the working device by the operating device; a cooler having an electric cooling fan; a temperature detection device for detecting a temperature of the object to be cooled by the cooler; a control device that controls a fan rotation speed, which is a rotation speed of the cooling fan, in accordance with the temperature of the object to be cooled detected by the temperature detection device; Equipped with The control device changes the characteristics of the fan rotation speed relative to the temperature of the object to be cooled depending on whether the operation locking device is in the permitted position or the prohibited position.

2. An electric motor; a working device driven by power of the electric motor; an operating device for operating the working device; an operation lock device that is switchable between an enabling position that enables operation of the working device by the operating device and a disabling position that disables operation of the working device by the operating device; a cooler having an electric cooling fan; a temperature detection device for detecting a temperature of the object to be cooled by the cooler; a control device that controls a fan rotation speed, which is a rotation speed of the cooling fan, in accordance with the temperature of the object to be cooled detected by the temperature detection device; a storage device that stores a plurality of fan control maps that indicate characteristics of the fan rotation speed with respect to the temperature of the object to be cooled; Equipped with the control device changes a characteristic of the fan rotation speed relative to the temperature of the object to be cooled depending on whether the operation locking device is in the permitted position or the prohibited position, the plurality of fan control maps include a first map and a second map that are different from each other, The control device controls the rotational drive of the cooling fan based on the first map when the operation locking device is in the prohibited position, and controls the rotational drive of the cooling fan based on the second map when the operation locking device is in the permitted position.

3. 3. The work machine according to claim 2, wherein the first map is configured to switch the fan rotation speed between 0 and a predetermined first fan rotation speed depending on the temperature of the object to be cooled.

4. 4. The work machine according to claim 3, wherein the first map is configured to switch the fan rotation speed to the first fan rotation speed when the value of the cooling target temperature rises from a value less than a predetermined first rotation rise temperature to the first rotation rise temperature while the fan rotation speed is 0, and to switch the fan rotation speed to 0 when the value of the cooling target temperature drops to a predetermined first rotation drop temperature lower than the first rotation rise temperature while the fan rotation speed is at the first fan rotation speed.

5. The second map is setting the fan rotation speed to a value greater than 0 when the value of the temperature to be cooled rises from a value less than a predetermined second rotation start temperature to the second rotation start temperature while the fan rotation speed is 0; When the value of the temperature to be cooled is equal to or higher than a first specified temperature that is set to a temperature higher than the second rotation start temperature, the fan rotation speed is set to a predetermined second fan rotation speed; When the value of the temperature of the object to be cooled is equal to or higher than the second rotation start temperature and lower than the first specified temperature, the fan rotation speed is set higher as the temperature of the object to be cooled increases within a range lower than the second fan rotation speed; The work machine according to any one of claims 2 to 4, wherein the work machine is configured to reduce the fan rotation speed to 0 when the value of the temperature to be cooled falls to a predetermined second rotation drop temperature that is lower than a second rotation rise temperature while the fan rotation speed is not 0.

6. The second map is when the value of the temperature to be cooled is equal to or higher than the second rotation start temperature and is lower than a second specified temperature that is set to a value lower than the first specified temperature, the fan rotation speed is set to a constant value lower than the second fan rotation speed; The work machine according to claim 5, wherein when the value of the temperature to be cooled is equal to or greater than the second specified temperature and less than the first specified temperature, the fan rotation speed is set higher as the temperature to be cooled increases within a range less than the second fan rotation speed.

7. the plurality of fan control maps includes a third map; when the operation lock device is in the permitted position and the operation device has not been operated for a predetermined time, the control device sets the rotation speed of the electric motor to an idle rotation speed and controls the cooling fan based on the third map; The work machine according to any one of claims 2 to 4, wherein the third map is configured to switch the fan rotation speed to a predetermined auto-idle rotation speed when the value of the cooling target temperature rises from a value less than a predetermined third rotation rise temperature to the third rotation rise temperature while the fan rotation speed is 0, and to switch the fan rotation speed to 0 when the value of the cooling target temperature falls to a predetermined third rotation drop temperature lower than the third rotation rise temperature while the fan rotation speed is at the auto-idle rotation speed.

8. The work machine according to claim 7, wherein the third map is common to the first map.

9. the cooling target of the cooler is a refrigerant for cooling a cooling target device mounted on the work machine, an abnormally high temperature detection device for detecting an abnormally high temperature of the equipment to be cooled; 6. The work machine according to claim 5, wherein the control device rotates the cooling fan at a third fan rotation speed that is higher than the second fan rotation speed when the abnormally high temperature detection device detects an abnormally high temperature and the temperature of the object to be cooled is equal to or higher than a third specified temperature that is set to a value higher than the second rotation start temperature.

10. The work machine according to claim 9, wherein the control device returns control of the cooling fan rotation speed to control based on the second map when the value of the cooling target temperature drops to a fourth specified temperature that is lower than the third specified temperature while the cooling fan is rotating at the third fan rotation speed.

11. The second map is when the value of the temperature to be cooled rises to a fourth rotation start temperature that is higher than the first specified temperature while the fan rotation speed is at the second fan rotation speed, the fan rotation speed is set to a fourth fan rotation speed that is higher than the second fan rotation speed; 6. The work machine according to claim 5, wherein the work machine is configured to reduce the fan rotation speed to the second fan rotation speed when the value of the temperature to be cooled drops to a predetermined fourth rotation drop temperature that is lower than a fourth rotation rise temperature and higher than the first specified temperature while the fan rotation speed is the fourth fan rotation speed.

12. the plurality of fan control maps include a fourth map, The fourth map is setting the fan rotation speed to a value greater than 0 when the value of the temperature to be cooled rises from a value less than the second rotation start temperature to the second rotation start temperature while the fan rotation speed is 0; When the value of the temperature to be cooled is equal to or higher than the first specified temperature, the fan rotation speed is set to a predetermined fifth fan rotation speed which is lower than the second fan rotation speed; When the value of the temperature of the object to be cooled is equal to or higher than the second rotation start temperature and lower than the first specified temperature, the fan rotation speed is set higher as the temperature of the object to be cooled increases within a range lower than the fifth fan rotation speed; the fan rotation speed is reduced to 0 when the value of the temperature to be cooled is reduced to the second rotation reduction temperature while the fan rotation speed is not 0, 6. The work machine according to claim 5, wherein the control device controls the cooling fan based on the second map when the rotation speed of the electric motor is set to a high value, and controls the cooling fan based on the fourth map when the rotation speed of the electric motor is set to a low value.

13. The fourth map is when the value of the temperature to be cooled rises to a fourth rotation start temperature that is higher than the first specified temperature while the fan rotation speed is at the fifth fan rotation speed, the fan rotation speed is set to a sixth fan rotation speed that is higher than the fifth fan rotation speed; 13. The work machine according to claim 12, wherein the work machine is configured to reduce the fan rotation speed to the fifth fan rotation speed when the value of the temperature to be cooled drops to a predetermined fourth rotation drop temperature that is lower than a fourth rotation rise temperature and higher than the first specified temperature while the fan rotation speed is the sixth fan rotation speed.

14. the cooler is a radiator for cooling cooling water that cools devices including the electric motor, the cooling fan is a radiator fan provided in the radiator, The work machine according to claim 2 , wherein the temperature detection device detects the temperature of the cooling water as the temperature of the object to be cooled.

15. the cooler is a radiator for cooling cooling water that cools devices including the electric motor, the cooling fan is a radiator fan provided in the radiator, The work machine according to claim 9 , wherein the temperature detection device detects the temperature of the cooling water as the temperature of the object to be cooled.

16. a hydraulic pump driven by the electric motor; a hydraulic actuator driven by the hydraulic pressure of the hydraulic oil discharged by the hydraulic pump, the cooler is an oil cooler for cooling the hydraulic oil, and the cooling fan is an oil cooler fan provided in the oil cooler, The work machine according to claim 2 , wherein the temperature detection device detects the temperature of the hydraulic oil as the temperature to be cooled.

17. a hydraulic pump driven by the electric motor; a hydraulic actuator driven by the hydraulic pressure of the hydraulic oil discharged by the hydraulic pump, the cooler is an oil cooler for cooling the hydraulic oil, and the cooling fan is an oil cooler fan provided in the oil cooler, The work machine according to claim 12, wherein the temperature detection device detects the temperature of the hydraulic oil as the temperature to be cooled.

18. a hydraulic pump driven by the electric motor; a hydraulic actuator driven by the hydraulic pressure of the hydraulic oil discharged by the hydraulic pump, The cooler includes a radiator for cooling cooling water that cools devices including the electric motor, and an oil cooler for cooling the hydraulic oil, The cooling fans include a radiator fan provided in the radiator and an oil cooler fan provided in the oil cooler, the temperature detection device detects the temperature of the cooling water and the temperature of the hydraulic oil as the temperature of the object to be cooled; the storage device stores a plurality of fan control maps for a radiator fan indicating a characteristic of the rotation speed of the radiator fan relative to the temperature of the cooling water, and a plurality of fan control maps for an oil cooler fan indicating a characteristic of the rotation speed of the oil cooler fan relative to the temperature of the hydraulic oil, 3. The work machine according to claim 2, wherein the control device controls the rotation speed of the radiator fan based on a plurality of fan control maps for the radiator fan, and controls the rotation speed of the oil cooler fan based on a plurality of fan control maps for the oil cooler fan.

Images