Electric construction machine

Abstract

A hydraulic excavator 1 includes an actuation sound device 25 that outputs a warning sound to the surroundings of machine bodies 2 to 4 while the machine bodies 2 to 4 are operating, and a machine body controller 24 controls the actuation sound device 25 so as to reduce the volume of the warning sound, output by the actuation sound device 25, in response to an increase in the rotation speed of cooling fans 22, 23. Surrounding workers are notified that a machine body is in operation while noise generated by the actuation sound device is suppressed.

Description

electric construction machinery

[0001] The present invention relates to an electric construction machine such as an electric hydraulic excavator.

[0002] Some construction machines, such as hydraulic excavators, are equipped with an electric motor that is driven by power supplied from a battery unit or an external power source, instead of an internal combustion engine as a power source (electrically-driven construction machines). Patent Document 1, for example, is a document disclosing prior art for such electric construction machines.

[0003] Patent Document 1 discloses a swivel work machine comprising a swivel base, a work device provided on the swivel base, a radiator fan that cools a radiator, an oil cooler fan that cools an oil cooler separately from the radiator fan, a battery unit, an electric motor that is driven by electricity output from the battery unit, and a hydraulic pump that discharges hydraulic oil by driving the electric motor, wherein the electric motor and the hydraulic pump are arranged to the side of the battery unit, and the radiator fan and the oil cooler fan are arranged to the side of the battery unit and above the hydraulic pump and the electric motor.

[0004] Japanese Patent Application Laid-Open No. 2021-080709

[0005] Electric construction machinery is characterized by its quieter operation noise compared to engine-powered construction machinery. Therefore, for example, if a nearby worker approaches a vehicle that is ready to operate and waiting, and the vehicle starts moving, there is a risk that the worker may come into contact with the vehicle. Therefore, in order to notify nearby workers that the vehicle is operating, it is conceivable to equip the vehicle with an acoustic vehicle alerting system (AVAS) that outputs an alarm sound while the vehicle is operating.

[0006] However, depending on the operating conditions of the aircraft, loud operating noises may be generated from equipment such as cooling fans, and the sound from the operating sound device may be superimposed on these operating noises, generating more noise than necessary and causing discomfort to the aircraft operator and surrounding workers.

[0007] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide an electric construction machine that can notify surrounding workers that the machine is in operation while suppressing the noise generated by the operating acoustic device.

[0008] In order to achieve the above-mentioned object, the present invention provides an electric construction machine comprising a lower running body, an upper rotating body rotatably mounted on the lower running body, a work device mounted on the upper rotating body and constituting a machine body together with the lower running body and the upper rotating body, an electric motor as a power source for the machine body, a cooling fan for cooling a circulating medium circulating within the machine body, and a machine body controller for controlling the rotation speed of the cooling fan, the electric construction machine comprising an actuation sound device that outputs a warning sound around the machine body while the machine body is in operation, and the machine body controller controls the actuation sound device so as to reduce the volume of the warning sound output by the actuation sound device in accordance with an increase in the rotation speed of the cooling fan.

[0009] According to the electric construction machine of the present invention, it is possible to notify surrounding workers that the machine is in operation while suppressing the generation of noise caused by the operating sound device.

[0010] 1 is a side view of an electric hydraulic excavator according to a first embodiment of the present invention. FIG. 2 is a top view of an electric hydraulic excavator according to the first embodiment of the present invention. FIG. 3 is a top view showing the state of the inside of a cab according to the first embodiment of the present invention. FIG. 4 is a functional block diagram of a machine controller involved in control of a cooling fan and an activated acoustic device according to the first embodiment of the present invention. FIG. 5 is a characteristic diagram showing the relationship between hydraulic oil temperature or cooling water temperature and the rotation speed of a cooling fan and the output of an activated acoustic device according to the first embodiment of the present invention. FIG. 6 is a flowchart showing the processing of a machine controller involved in control of a cooling fan and an activated acoustic device according to the first embodiment of the present invention. FIG. 7 is a flowchart showing a modified example of the processing of a machine controller involved in control of a cooling fan and an activated acoustic device according to the first embodiment of the present invention. FIG. 8 is a characteristic diagram showing the relationship between hydraulic oil temperature or cooling water temperature and the rotation speed of a cooling fan and the output of an activated acoustic device according to a second embodiment of the present invention. FIG. 9 is a flowchart showing the processing of a machine controller involved in control of a cooling fan and an activated acoustic device according to the second embodiment of the present invention.

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that, in this embodiment, an electric hydraulic excavator will be described as an example, but the present invention can also be applied to other electric construction machines. In addition, in each drawing, the same or equivalent components are given the same reference numerals, and duplicate explanations will be omitted as appropriate.

[0012] 1 is a side view of an electric hydraulic excavator (hereinafter referred to as hydraulic excavator) according to a first embodiment of the present invention. The hydraulic excavator 1 comprises a crawler-type undercarriage 2 capable of traveling in a forward-backward direction, an upper rotating body 3 rotatably mounted on the undercarriage 2, and a working device 4 provided in front of the upper rotating body 3. The undercarriage 2, the upper rotating body 3, and the working device 4 constitute the machine body of the hydraulic excavator 1. The hydraulic excavator 1 travels around a work site on the undercarriage 2, and performs work such as excavating earth and sand by rotating the upper rotating body 3 and elevating the working device 4.

[0013] A power source 9 including an electric motor 10 is mounted on the upper rotating body 3. The hydraulic excavator 1 is configured to operate when power is supplied to the power source 9 from an external power source (not shown) via a power supply cable 12. Note that instead of supplying power from an external power source, a battery unit may be mounted on the upper rotating body 3 and power may be supplied to the power source 9 from the battery unit.

[0014] The working device 4 includes a swing post 4A attached to the front end of the revolving frame 5 so as to be swingable left and right, a boom 4B attached to the swing post 4A so as to be able to move up and down, an arm 4C rotatably attached to the tip of the boom 4B, and a bucket 4D rotatably attached to the tip of the arm 4C. The boom 4B, arm 4C, and bucket 4D are driven by a boom cylinder 4E, an arm cylinder 4F, and a bucket cylinder 4G. In addition, a swing cylinder (not shown) is provided between the revolving frame 5 and the swing post 4A to swing the swing post 4A left and right.

[0015] The upper rotating body 3 comprises a rotating frame 5 serving as a base that is rotatably attached to the lower running body 2, a driver's cab 6 provided on the rotating frame 5, a building cover 7, a power source 9, and a counterweight 13.

[0016] The cab 6 is provided on the front left side of the revolving frame 5. The cab 6 is formed in a vertically long box shape surrounded by a front portion 6A, a rear portion 6B, a left side portion 6C, a right side portion 6D, and a top portion 6E. A door 6F is attached to the left side portion 6C of the cab 6, and the operator gets in and out of the cab 6 by opening and closing the door 6F.

[0017] The building cover 7 is located on the revolving frame 5 and is positioned in front of the counterweight 13. The building cover 7 and the counterweight 13 form a machine room 8 on the revolving frame 5, and the machine room 8 houses onboard equipment such as a power source 9, a hydraulic pump 11, and a control valve (not shown).

[0018] The power source 9 is mounted on the revolving frame 5 and located in front of the counterweight 13, and is housed in a machine room 8 surrounded by the building cover 7 and the counterweight 13. The power source 9 has an electric motor 10 and a motor control device 36 (shown in FIG. 4 ) that controls the operation of the electric motor 10. The electric motor 10 is formed, for example, by a three-phase induction motor, and is rotated by receiving power (power feeding) from an external power source (not shown), such as a commercial power source that supplies three-phase AC power, via a power feed cable 12, thereby driving the hydraulic pump 11. In this case, the operation control (power feed control) of the electric motor 10 is performed by the motor control device 36.

[0019] The hydraulic pump 11 is connected to the output shaft of the electric motor 10. When driven by the electric motor 10, the hydraulic pump 11 pressurizes hydraulic oil stored in a hydraulic oil tank 20 (shown in FIG. 2 ) and discharges the hydraulic oil toward a hydraulic motor for traveling and a hydraulic motor for swinging (neither of which are shown) mounted on the hydraulic excavator 1, a boom cylinder 4E, an arm cylinder 4F, a bucket cylinder 4G, etc., provided on the work implement 4.

[0020] The power supply cable 12 electrically connects an external power supply (not shown) and the power source 9. One end of the power supply cable 12 is connected to the external power supply, and the other end is connected to a motor control device 36 (shown in FIG. 4 ) of the power source 9. A cable holder 15 holds the power supply cable 12 at a midpoint in its length.

[0021] The counterweight 13 is provided at the rear end of the revolving frame 5 to balance the weight with the working device 4. The counterweight 13 is made of a block body having a rectangular frame shape as a whole, and is integrally formed by casting using a metal material such as cast iron or cast steel. The counterweight 13 rises upward from the rear end of the revolving frame 5 and covers the mounted equipment such as the electric motor 10 and hydraulic pump 11 from the rear side.

[0022] A rectangular inspection opening 13B is provided on the rear surface 13A of the counterweight 13. The inspection opening 13B is located in the center of the counterweight 13 in the vertical and horizontal directions, and penetrates in the front-to-rear direction from the rear surface 13A to the front surface (not shown) of the counterweight 13. The inspection opening 13B is connected to the machine room 8 surrounded by the building cover 7 and the counterweight 13. This allows inspection of the power source 9, including the electric motor 10, housed in the machine room 8 to be performed from the rear surface 13A of the counterweight 13 through the inspection opening 13B.

[0023] The openable cover 14 is provided on the rear surface 13A of the counterweight 13. The openable cover 14 is formed in the shape of a rectangular plate and opens and closes to cover the inspection opening 13B of the counterweight 13. The openable cover 14 moves up and down between a closed position where the inspection opening 13B of the counterweight 13 is closed as shown by the solid line in Figure 1, and an open position where the inspection opening 13B of the counterweight 13 is open as shown by the dashed line in Figure 1.

[0024] Therefore, when inspecting the power source 9 and other components housed in the machinery room 8, the openable cover 14 is moved to the open position, as shown by the dashed line in Figure 1, to open the inspection opening 13B of the counterweight 13. This allows the worker to access the power source 9 from the rear surface 13A of the counterweight 13 through the inspection opening 13B.

[0025] FIG. 2 is a top view of the hydraulic excavator 1. The working device 4 is not shown in FIG. 2 . To the right of the operator's cab 6 on the revolving frame 5, there are provided an electric motor 10, a hydraulic oil tank 20 for storing hydraulic oil, a cooling water tank 21 for storing cooling water, a hydraulic oil cooling fan 22 for blowing air into the hydraulic oil tank 20 to cool the hydraulic oil, a cooling water cooling fan 23 for blowing air into the cooling water tank 21 to cool the cooling water, and a machine controller 24 for controlling the operation of the machine units 2 to 4. At the left and right rear positions of the upper revolving body 3, there are provided actuation sound devices 25a, 25b (hereinafter referred to as actuation sound devices 25) for notifying nearby workers that the machine units 2 to 4 are in operation. An oil temperature sensor 20a (shown in FIG. 4) for detecting the temperature of the hydraulic oil (hydraulic oil temperature) is attached to the hydraulic oil tank 20. A water temperature sensor 21a (shown in FIG. 4) for detecting the temperature of the cooling water (cooling water temperature) is attached to the cooling water tank 21.

[0026] 3 is a top view showing the interior of the cab 6. A seat 30 on which an operator sits is provided in a central rear position within the cab 6. Travel control levers 31a and 31b (hereinafter referred to as travel control levers 31) for operating the undercarriage 2 are provided in front of the seat 30, and work control levers 32a and 32b (hereinafter referred to as work control levers 32) are provided on the left and right sides of the seat 30. A gate lock lever 33 (locking device) is provided diagonally forward and left of the seat 30 (near the door 6F). When the gate lock lever 33 is operated to, for example, a lowered position (unlocked position), the gate lock lever 33 closes the entrance to the cab 6, and the operation of the travel control lever 31 and the work control lever 32 is enabled (locked state). Furthermore, when the gate lock lever 33 is operated to, for example, a raised position (locked position), the entrance to the operator's cab 6 is opened, and operation of the travel control levers 31a, 31b and the work control levers 32a, 32b is disabled (unlocked state). In this embodiment, the locked state corresponds to the machines 2 to 4 not being in operation, and the unlocked state corresponds to the machines 2 to 4 being in operation. Note that in this embodiment, the unlocked state is described as the machines 2 to 4 being in operation, but this is not limited thereto. For example, the machines 2 to 4 may be considered to be in operation when the unlocked state is in operation and the travel control lever 31 or the work control lever 32 is operated. A speed control dial 34 (target rotation speed indicator) for indicating the rotation speed of the electric motor 10 is provided behind the right-side work control lever 32b. Note that the target rotation speed indicator may be configured as a touch panel monitor. Pressure sensors 35a, 35b, 35c (shown in FIG. 4) for detecting the operation of each are provided on the travel control lever 31, the work control lever 32, and the gate lock lever 33. Instead of providing the pressure sensors 35a, 35b, 35c, the travel control lever 31, the work control lever 32, and the gate lock lever 33 may be electronically controlled, and the machine controller 24 may directly detect the operation of each.

[0027] 4 is a functional block diagram of the aircraft controller 24 involved in controlling the cooling fans 22, 23 and the activated sound device 25. The aircraft controller 24 includes a signal input unit 24a, an arithmetic processing unit 24b, and a signal output unit 24c. The aircraft controller 24 includes an arithmetic unit such as a CPU, storage devices such as a ROM and RAM, and an input / output interface for inputting and outputting signals to and from external devices, and realizes the functions of each unit by executing programs stored in the ROM or the like.

[0028] The hydraulic oil cooling fan 22 includes a fan 22a and a fan controller 22b that controls the rotation speed of the fan 22a. The fan controller 22b controls the rotation speed of the fan 22a in response to a control signal input from a signal output unit 24c. The coolant cooling fan 23 includes a fan 23a and a fan controller 23b that controls the rotation speed of the fan 23a. The fan controller 23b controls the rotation speed of the fan 23a in response to a control signal input from the signal output unit 24c. The rotation speeds of the cooling fans 22, 23 are controlled, for example, by PWM control. In this embodiment, the machine controller 24 is configured to estimate the rotation speeds of the cooling fans 22, 23 from command values ​​sent to the fan controllers 22b, 23b. However, a rotation speed sensor may be provided in the fans 22a, 23a, and a signal from the rotation speed sensor may be input to the machine controller 24.

[0029] Signals from pressure sensors 35a to 35c, temperature sensors 20a and 21a, and speed control dial 34 are input to signal input unit 24a. Based on the signals input to signal input unit 24a, calculation processing unit 24b determines the rotation speed of electric motor 10, the rotation speed of cooling fans 22 and 23, and the output (corresponding to volume) of activated sound device 25. Based on the calculation results of calculation processing unit 24b, signal output unit 24c outputs control signals to motor control device 36, fan controllers 22b and 23b, and activated sound device 25.

[0030] FIG. 5 is a characteristic diagram showing the relationship between hydraulic oil temperature or cooling water temperature, the rotation speed of the cooling fans 22, 23, and the output of the activated sound device 25. As the hydraulic oil temperature or cooling water temperature increases, the rotation speed of the cooling fans 22, 23 increases. On the other hand, as the hydraulic oil temperature or cooling water temperature increases, the output of the activated sound device 25 decreases. In other words, as the rotation speed of the cooling fans 22, 23 increases, the output of the activated sound device 25 decreases. In other words, the higher the rotation speed of the cooling fans 22, 23, the lower the volume of the activated sound device 25 is set, and the lower the rotation speed of the cooling fans 22, 23, the higher the volume of the activated sound device 25 is set. The reason for reducing the output of the activated sound device 25 as the rotation speed of the cooling fans 22, 23 increases is that even if the volume of the activated sound device 25 is reduced, the noise of the cooling fans 22, 23 increases as the rotation speed of the cooling fans 22, 23 increases, making it clear that the aircraft 2-4 are in operation. Furthermore, when the rotation speed of the cooling fans 22, 23 increases and exceeds the threshold value R1 (when the hydraulic oil temperature or the coolant temperature increases and exceeds the threshold value T1), the output of the actuation sound device 25 decreases to 0 (zero). That is, when the rotation speed of the cooling fans 22, 23 exceeds the threshold value R1 (when the hydraulic oil temperature or the coolant temperature exceeds the threshold value T1), the actuation sound device 25 stops outputting the notification sound. Also, when the rotation speed of the cooling fans 22, 23 falls below the threshold value R1 (when the hydraulic oil temperature or the coolant temperature falls below the threshold value T1), the actuation sound device 25 outputs the notification sound. This is because, when the rotation speed of the cooling fans 22, 23 exceeds the threshold value R1, the noise of the cooling fans 22, 23 alone is enough to notify the user that the aircraft 2 to 4 are operating. By controlling the output of the actuation sound device 25 in this manner, it is possible to notify the user that the aircraft 2 to 4 are operating while suppressing the generation of noise generated by the actuation sound device. The characteristics and threshold values ​​R1, T1 shown in FIG. 5 may be set separately for the hydraulic oil cooling fan 22 and the coolant cooling fan 23.

[0031] 4, the motor control device 36 controls the rotation speed of the electric motor 10 in response to the control signal input from the signal output unit 24c. Specifically, the motor control device 36 controls the rotation speed of the electric motor 10 so that it matches the rotation speed indicated by the speed control dial 34 (indicated rotation speed).

[0032] 6 is a flowchart showing the processing of the machine controller 24 relating to the control of the cooling fans 22, 23 and the actuated sound device 25. This flowchart illustrates an example of the flow from the start to the end of work. Each step will be explained below.

[0033] The machine controller 24 first determines whether or not it has detected that the gate lock lever 33 has been lowered (unlocked state) (step S101). If the determination result of step S101 is No, the machine controller 24 executes the determination of step S101 again.

[0034] If the determination result in step S101 is Yes, the activation sound device 25 is caused to start outputting a warning sound (step S102). As a result, the operation of the machines 2 to 4 becomes possible (unlocked state) using the control levers 31, 32, and at the same time, output of the warning sound starts. At this time, the volume of the output warning sound is determined according to the characteristics diagram in FIG. 5 based on the rotation speed of the cooling fans 22, 23 obtained in advance.

[0035] Following step S102, the operation of the control levers 31 and 32 is detected (step S103).

[0036] Following step S103, it is determined whether or not an increase in the hydraulic oil temperature or the cooling water temperature has been detected (step S104). If the determination result in step S104 is No, the determination in step S104 is executed again.

[0037] If the determination result in step S104 is Yes, the rotation speed of the hydraulic oil cooling fan 22 or the coolant cooling fan 23 is increased, and the volume of the actuation sound device 25 is reduced in accordance with the increase in the rotation speed of the higher one of the cooling fans 22, 23 (step S105). As a result, the volume of the actuation sound device 25 is reduced as the noise of the louder one of the cooling fans 22, 23 increases.

[0038] After step S105, it is determined whether the hydraulic oil temperature or the cooling water temperature exceeds the threshold value T1 (step S106). If the determination result in step S106 is No, the process returns to step S105.

[0039] If the determination result in step S106 is Yes, the operation sound device 25 is caused to stop outputting the warning sound, and the rotation speed of the hydraulic oil cooling fan 22 or the coolant cooling fan 23 is increased (step S107). As a result, when the noise of the hydraulic oil cooling fan 22 or the coolant cooling fan 23 becomes sufficiently large, the output of the warning sound is stopped.

[0040] Following step S107, it is determined whether the hydraulic oil temperature or the coolant temperature has become equal to or lower than the threshold value T1 (step S108).

[0041] If the determination result in step S108 is Yes, the rotation speed of the hydraulic oil cooling fan 22 or the coolant cooling fan 23 is reduced, and the acoustic device 25 is caused to start outputting a warning sound (step S109). As a result, when the noise of the louder one of the hydraulic oil cooling fan 22 and the coolant cooling fan 23 becomes quieter as the hydraulic oil temperature or the coolant temperature drops, output of the warning sound starts.

[0042] Following step S109, or if the determination result of step S108 is No, it is determined whether or not it has been detected that the gate lock lever 33 has been raised (locked state) (step S110). If the determination result of step S110 is No, the determination of step S110 is executed again.

[0043] If the determination result in step S110 is Yes, the activation sound device 25 is caused to stop outputting the warning sound (step S111), and the flow ends. As a result, the operation of the machines 2 to 4 by the control levers 31, 32 becomes impossible (locked state), and the output of the warning sound is stopped at the same time.

[0044] 7 is a flowchart showing a modified example of the processing of the aircraft controller 24 relating to the control of the cooling fans 22, 23 and the actuated sound device 25 in the first embodiment. As with FIG. 6, this flowchart illustrates the flow from the start to the end of the work. Each step will be described below.

[0045] The machine controller 24 first determines whether or not it has detected that the gate lock lever 33 has been lowered (unlocked state) (step S201). If the determination result of step S201 is No, the machine controller 24 executes the determination of step S201 again.

[0046] If the determination result in step S201 is Yes, the activation sound device 25 is caused to start outputting a warning sound (step S202). As a result, the operation of the machines 2 to 4 by the control levers 31, 32 becomes impossible (locked state) and the output of the warning sound starts at the same time. At this time, the volume of the output warning sound is determined according to the characteristics diagram in FIG. 5 based on the rotation speed of the cooling fans 22, 23 obtained in advance.

[0047] Following step S202, the displacement of the speed control dial 34 is detected (step S203).

[0048] Following step S203, the rotation speed indicated by the speed control dial 34 (instructed rotation speed) is sent to the motor control device 36 (step S204). As a result, the rotation speed of the electric motor 10 is controlled so as to match the instructed rotation speed.

[0049] Following step S204, an increase in the hydraulic oil temperature or the cooling water temperature is detected (step S205).

[0050] Following step S205, the fan controllers 22b and 23b are instructed to lower the hydraulic oil temperature or the cooling water temperature (step S206).

[0051] Following step S206, it is determined whether the rotation speed of the hydraulic oil cooling fan 22 or the coolant cooling fan 23 has increased (step S207).

[0052] If the determination result in step S207 is No, the volume of the notification sound remains the same (step S208).

[0053] If the determination result in step S207 is Yes, the duty ratio of the input pulse, which is the control signal to the actuation sound device 25, is reduced (step S209), and the volume of the notification sound is reduced (step S210).

[0054] Following step S210, it is determined whether the rotation speed of the hydraulic oil cooling fan 22 or the coolant cooling fan 23 exceeds a threshold value R1 (step S211).

[0055] If the determination result in step S211 is Yes, the activation sound device 25 is caused to stop outputting the notification sound (step S212).

[0056] Following step S212, or if the determination result of step S211 is No, the displacement of the speed control dial 34 is detected (step S213). Here, it is assumed that the speed control dial 34 has instructed a decrease in the indicated rotation speed. This decreases the rotation speed of the electric motor 10, and accordingly, the temperatures of the hydraulic oil and the coolant decrease.

[0057] Following step S213, the rotation speeds of the hydraulic oil cooling fan 22 and the coolant cooling fan 23 are reduced (step S214).

[0058] Following step S214, the activation sound device 25 starts to output a notification sound (step S215). This is because the noise from the cooling fans 22, 23 alone is not enough to notify the driver that the machines 2 to 4 are in operation.

[0059] Following step S215, it is determined whether or not it has been detected that the gate lock lever 33 has been raised (locked state) (step S216). If the determination result of step S216 is No, the determination of step S216 is executed again.

[0060] If the determination result in step S216 is Yes, the activation sound device 25 stops outputting the warning sound (step S217), and the flow ends. As a result, the operation of the machines 2 to 4 by the control levers 31, 32 becomes impossible (locked state), and the output of the warning sound stops.

[0061] (Summary) In the first embodiment, the hydraulic excavator 1 (electrically driven construction machine) includes a lower running body 2, an upper rotating body 3 rotatably mounted on the lower running body 2, a work device 4 mounted on the upper rotating body 3 and constituting a machine body together with the lower running body 2 and the upper rotating body 3, an electric motor 10 which is a power source 9 for the machine bodies 2 to 4, cooling fans 22, 23 which cool the circulating medium circulating within the machine bodies 2, 3, and a machine body controller 24 which controls the rotation speed of the cooling fans 22, 23, and is equipped with an actuation sound device 25 which outputs a warning sound around the machine bodies while the machine bodies 2 to 4 are in operation, and the machine body controller 24 controls the actuation sound device 25 to decrease the volume of the warning sound output by the actuation sound device 25 in response to an increase in the rotation speed of the cooling fans 22, 23, and to increase the volume of the warning sound output by the actuation sound device 25 in response to a decrease in the rotation speed of the cooling fans 22, 23.

[0062] According to the first embodiment configured as described above, the volume of the notification sound output by the actuation sound device 25 decreases as the operating noise of the cooling fans 22, 23 increases, and the volume of the notification sound output by the actuation sound device 25 increases as the operating noise of the cooling fans 22, 23 decreases. This makes it possible to notify nearby workers that the machines 2-4 are operating while suppressing noise generated by the actuation sound device 25. Furthermore, by suppressing the volume of the actuation sound device 25, it is possible to reduce the power consumption of the actuation sound device 25 and reduce the discomfort caused to the operator and nearby workers by the excessive volume of the notification sound output by the actuation sound device 25. Note that, as shown in FIG. 5 , the rotation speed of the cooling fans 22, 23 is correlated with the hydraulic oil temperature or the coolant temperature. Therefore, the machine controller 28 may change the volume of the notification sound based on the hydraulic oil temperature or the coolant temperature (i.e., indirectly based on the rotation speed of the cooling fans 22, 23) rather than directly based on the rotation speed of the cooling fans 22, 23.

[0063] Furthermore, the machine controller 24 in the first embodiment continuously decreases the volume of the actuated sound device 25 in response to an increase in the rotation speed of the cooling fans 22, 23, and continuously increases the volume of the actuated sound device 25 in response to a decrease in the rotation speed of the cooling fans 22, 23. This prevents the volume of the actuated sound device 25 from changing discontinuously, further reducing the discomfort felt by the operator and surrounding workers.

[0064] Moreover, in the first embodiment, the hydraulic excavator 1 includes a hydraulic oil tank 20 that stores hydraulic oil as the circulating medium, and a cooling water tank 21 that stores cooling water as the circulating medium, and the cooling fans 22, 23 include a hydraulic oil cooling fan 22 that blows air into the hydraulic oil tank 20 to cool the hydraulic oil, and a cooling water cooling fan 23 that blows air into the cooling water tank 21 to cool the cooling water, and the machine controller 24 controls the volume of the actuation sound device 25 in accordance with the higher of the rotation speeds of the hydraulic oil cooling fan 22 and the cooling water cooling fan 23. As a result, the volume of the actuation sound device 25 is controlled in accordance with the volume of the actuation sound device 25 in accordance with an increase in the operating noise of the hydraulic oil cooling fan 22 or the cooling water cooling fan 23, whichever has the louder operating noise. Therefore, it is possible to notify nearby workers that the machine bodies 2 to 4 are in operation while minimizing the noise generated by the actuation sound device 25.

[0065] Moreover, in the first embodiment, the hydraulic excavator 1 includes a cab 6 provided on the upper rotating body 3, and a gate lock lever 33 (locking device) provided in the cab 6 for switching between a locked state in which driving of the work implement 4 is prohibited and an unlocked state in which driving of the work implement 4 is permitted, and the machine controller 24 controls the actuation sound device 25 to output the notification sound when the gate lock lever 33 switches to the unlocked state, and controls the actuation sound device 25 to stop output of the notification sound when the gate lock lever 33 switches to the locked state. This makes it possible to start outputting the notification sound at the same time as operation of the machine bodies 2 to 4 by the operation levers 31, 32 becomes possible (unlocked state), and to stop outputting the notification sound at the same time as operation of the machine bodies 2 to 4 by the operation levers 31, 32 becomes impossible (locked state).

[0066] The second embodiment of the present invention will be described below, focusing on the differences from the first embodiment. In the second embodiment, a configuration was described in which volume control was performed by adjusting the duty ratio of the input pulse to the actuated sound device 25. In the second embodiment, a configuration will be described in which volume control is performed by storing a plurality of sound source data with different volumes in the actuated sound device 25 and switching the sound source data to be used in response to an instruction from the aircraft controller 24.

[0067] 8 is a characteristic diagram showing the relationship between the hydraulic oil temperature or coolant temperature, the rotation speed of the cooling fans 22, 23, and the output of the actuated sound device 25 in the second embodiment. The actuated sound device 25 switches the sound source data to be used so that the volume gradually decreases as the rotation speed of the cooling fans 22, 23 increases, and so that the volume gradually increases as the rotation speed of the cooling fans 22, 23 decreases. The actuated sound device 25 in this embodiment stores three sound source data with different volume levels. The operating sound device 25 uses the sound source data with the highest volume when the rotation speed of the cooling fans 22, 23 is equal to or lower than the threshold value R3 (when the hydraulic oil temperature or the coolant temperature is equal to or lower than the threshold value T3), uses sound source data with a medium volume when the rotation speed of the cooling fans 22, 23 is greater than the threshold value R3 but equal to or lower than the threshold value R2 (when the hydraulic oil temperature or the coolant temperature is greater than the threshold value T3 but equal to or lower than the threshold value T2), uses the sound source data with the lowest volume when the rotation speed of the cooling fans 22, 23 is greater than the threshold value R2 but equal to or lower than the threshold value R1 (when the hydraulic oil temperature or the coolant temperature is greater than the threshold value T2 but equal to or lower than the threshold value T1), and stops output when the rotation speed of the cooling fans 22, 23 is greater than the threshold value R1 (when the hydraulic oil temperature or the coolant temperature is greater than the threshold value T1). Note that the characteristics and threshold values ​​R1 to R3 and T1 to T3 shown in FIG. 8 may be set separately for the hydraulic oil cooling fan 22 and the coolant cooling fan 23. Furthermore, the number of sound source data stored in the differential sound device 25 is not limited to three.

[0068] 9 is a flowchart showing the processing of the machine controller 24 related to the control of the cooling fans 22, 23 and the actuated sound device 25 in the second embodiment. As with FIG. 6, this flowchart illustrates the flow from the start to the end of work. Below, differences from the modified example of the first embodiment (shown in FIG. 7) will be described.

[0069] In the second embodiment, if the determination result in step S207 is Yes, step S210A is executed instead of steps S209 and S210 (shown in FIG. 7). In step S210A, the differential sound device 25 is instructed to use sound source data with a lower volume than the sound source data currently being used. The method of selecting sound source data is as described with reference to FIG. 8.

[0070] (Summary) In the second embodiment, the aircraft controller 24 gradually decreases the volume of the actuated sound device 25 in response to an increase in the rotation speed of the cooling fans 22, 23, and gradually increases the volume of the actuated sound device 25 in response to a decrease in the rotation speed of the cooling fans 22, 23.

[0071] According to the second embodiment configured as described above, in a hydraulic excavator 1 equipped with an actuation sound device 25 that selectively uses a plurality of pre-stored sound source data, it is possible to notify surrounding workers that the machine bodies 2 to 4 are in operation while suppressing the generation of noise caused by the actuation sound device 25.

[0072] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to add part of the configuration of one embodiment to the configuration of another embodiment, or to delete part of the configuration of one embodiment or replace it with part of another embodiment.

[0073] 1...hydraulic excavator (electric construction machine), 2...undercarriage (machine body), 3...upper rotating body (machine body), 4...working device (machine body), 4A...swing post, 4B...boom, 4C...arm, 4D...bucket, 4E...boom cylinder, 4F...arm cylinder, 4G...bucket cylinder, 5...swivel frame, 6...operator's cab, 6A...front portion, 6B...rear portion, 6C...left side portion, 6D...right side portion, 6E...top portion, 6F...door, 7...building cover, 7A...left cover, 7B...right cover, 8...machine room, 9...power source, 10...electric motor, 11...hydraulic pump, 12...power supply cable, 13...counterweight, 13A...rear, 13B...inspection opening, 14...opening / closing cover, 15...cable holder, 20... Hydraulic oil tank, 20a...oil temperature sensor (temperature sensor), 21...cooling water tank, 21a...water temperature sensor (temperature sensor), 22...hydraulic oil cooling fan, 22a...fan, 22b...fan controller, 23...cooling water cooling fan, 23a...fan, 23b...fan controller, 24...machine controller, 24a...signal input unit, 24b...arithmetic processing unit, 24c...signal output unit, 25, 25a, 25b...activation sound device, 30...seat, 31, 31a, 31b...travel operation control lever, 32, 32a, 32b...work operation control lever, 33...gate lock lever (locking device), 34...speed control dial, 35a, 35b, 35c...pressure sensor, 36...motor control device.

Claims

1. An electric construction machine comprising: a lower running body; an upper rotating body rotatably mounted on the lower running body; a working device mounted on the upper rotating body and constituting a machine body together with the lower running body and the upper rotating body; an electric motor as a power source for the machine body; a cooling fan for cooling a circulating medium circulating within the machine body; and a machine body controller for controlling the rotation speed of the cooling fan; wherein the electric construction machine further comprises an actuation sound device that outputs a warning sound around the machine body while the machine body is in operation, and the machine body controller controls the actuation sound device to reduce the volume of the warning sound output by the actuation sound device in accordance with an increase in the rotation speed of the cooling fan.

2. An electric construction machine according to claim 1, characterized in that the machine controller continuously reduces the volume of the operating sound device in accordance with an increase in the rotation speed of the cooling fan.

3. An electric construction machine according to claim 1, characterized in that the machine controller reduces the volume of the operating sound device in stages in accordance with an increase in the rotation speed of the cooling fan.

4. An electric construction machine as claimed in claim 1, comprising a hydraulic oil tank for storing hydraulic oil as the circulating medium, and a cooling water tank for storing cooling water as the circulating medium, wherein the cooling fans include a hydraulic oil cooling fan that blows air into the hydraulic oil tank to cool the hydraulic oil, and a cooling water cooling fan that blows air into the cooling water tank to cool the cooling water, and wherein the machine controller controls the volume of the operating sound device in accordance with the higher of the rotation speeds of the hydraulic oil cooling fan and the cooling water cooling fan.

5. An electric construction machine as described in claim 1, comprising: a cab provided on the upper rotating body; and a locking device provided in the cab for switching between a locked state that prohibits the driving of the work equipment and an unlocked state that allows the driving of the work equipment, wherein the machine controller controls the actuation sound device to output the warning sound when the locking device switches to the unlocked state, and controls the actuation sound device to stop the warning sound when the locking device switches to the locked state.

6. An electric construction machine according to claim 1, characterized in that the machine controller controls the activation sound device to stop the warning sound when the rotation speed of the cooling fan exceeds a predetermined threshold.

7. An electric construction machine as described in claim 1, further comprising a temperature sensor for detecting the temperature of the circulating medium, and wherein the machine controller controls the activation sound device to stop the warning sound when the temperature of the circulating medium detected by the temperature sensor exceeds a predetermined threshold.

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