JP2018020639A - Electric work vehicle and control device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible for an operator to safely carry out an operation without interruption as much as possible when being switched from an electric mode to a PTO mode during operation of a work machine of an electric work vehicle.SOLUTION: When a charging rate of a battery is smaller than a lower limit value during stop of an engine in an electric mode, a vehicle side controller is designed to start the engine and carry out an engine restart mode that makes a switching from the electric mode to a PTO mode. When switching time measured by a timer, which corresponds to time elapsed from time when the engine restart mode is started to time when being switched to the PTO mode, is longer than an upper limit value, the vehicle side controller is designed to stop a power supply from the battery to an electric motor.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electric work vehicle including a PTO driven by an engine, a battery, an electric motor driven by electric power of the battery, and a hydraulic pump driven by the PTO or the electric motor, and a control device thereof.

  Conventionally, it is known that this type of electric work vehicle includes a control device that switches to a PTO mode in which a hydraulic pump is driven by a PTO or an electric mode in which a hydraulic pump is driven by an electric motor.

  And in order to prevent the work machine from operating unexpectedly when the electric motor is unable to drive the pump normally due to the battery running out of the battery or failure of the electrical system when the hydraulic pump is in the motor drive state For example, in Patent Document 1, the control device controls the operation of the valve device so that the work implement is urgently stopped when the remaining amount of the battery is lower than a predetermined lower limit value in the electric motor driving state.

  Further, as in the electric work vehicle of Patent Document 2, there is known an apparatus that automatically returns the engine to switch to the PTO mode when the SOC decreases in the electric mode.

JP 2014-122100 A JP 2013-060280 A

  However, in the electric work vehicle described in Patent Document 1, if the remaining amount of the battery decreases while the work machine is operating, the work machine is stopped and the work is interrupted each time, so there is a problem in workability. .

  On the other hand, in the electric work vehicle described in Patent Document 2, since the work mode is automatically switched from the electric mode to the PTO mode during operation, the work is not normally interrupted.

  However, when switching from the electric mode to the PTO mode, a switching time is required because of the connection / disconnection of the PTO device and the connection / disconnection of the clutch. If this switching time becomes longer than usual for some reason such as a failure, the driving force to the hydraulic pump is temporarily cut off. In this case, the working machine that is in operation seems to have stopped once for the operator, but suddenly starts to move after switching, so that the operator may not be able to cope with the unexpected movement.

  The present invention has been made in view of the above points, and the object of the present invention is to ensure that an operator can safely and without interruption when switching from the electric mode to the PTO mode when the work implement is operating. It is to be able to work.

  In order to achieve the above object, in the present invention, when the switching time is longer than the upper limit value, the power supply from the battery to the electric motor is stopped.

Specifically, in the first invention,
Engine,
A PTO driven by the engine;
Battery,
An electric motor driven by the electric power of the battery;
A hydraulic pump driven by the PTO or the electric motor;
A working machine driven by the hydraulic pump;
Assume an electric work vehicle including a control device that switches to a PTO mode in which the hydraulic pump is driven by the PTO or an electric mode in which the hydraulic pump is driven by the electric motor. The fourth invention is premised on a control device provided in the electric work vehicle.

And between the said electric mode and the said PTO mode, the engine restart mode controlled by the said control apparatus is provided,
In the engine restart mode, when the engine is stopped and the work machine is operating in the electric mode, the engine is started when the charge rate of the battery is smaller than a lower limit value. Configured to switch to mode,
The control device includes a timer for measuring a switching time for switching from the electric mode to the PTO mode after starting the engine restart mode, and when the switching time measured by the timer is longer than an upper limit value, The power supply from the battery to the electric motor is stopped.

  According to the above configuration, during operation of the work machine, the engine is automatically started when the battery charge rate (SOC) is smaller than the lower limit value, so that the operator's hand is not bothered. Also, if for some reason it takes longer than the upper limit value to switch from the electric mode to the PTO mode even though the SOC is lower than the lower limit value, the hydraulic pump will be driven if the work implement is continued to operate. When the power is temporarily cut, the work machine may temporarily stop and suddenly move, which is dangerous for the worker. In that respect, according to the above configuration, the control device determines whether the switching time is long or short, and if there is no problem, the operation of the work machine is continued to eliminate the work interruption of the operator. For example, the safety of the worker can be secured by stopping the work machine. As a result, when switching from the electric mode to the PTO mode, the worker can perform the work safely and without interrupting the work as much as possible.

  In the case of an electric garbage truck, even if the electric power supply to the electric motor stops and an emergency stop occurs, unlike the aerial work vehicle, for example, the dust loading device etc. only stops, ensuring the safety of workers. Is done.

In the second invention, in the first invention,
The control device
A vehicle-side control device for controlling the vehicle;
A body side control device for controlling the body mounted on the vehicle,
The power supply from the battery to the electric motor is stopped by turning off the power of the bodywork side control device.

  According to said structure, the electric power supply from a battery to an electric motor is stopped reliably with a simple structure.

In the third invention, in the second invention,
The PTO switch for setting the PTO mode is a momentary switch that self-resets after being pressed regardless of the PTO mode or the electric mode.

  That is, if the PTO switch is an alternate type switch as in the past, the body side repeats stopping and driving while the PTO switch is physically kept on, so when the PTO switch automatically switches to the PTO mode However, according to the above configuration, the momentary switch is a so-called rebound switch, and returns to the state before the press after the operation, so that the state of the PTO switch does not match the actual mode. Even if the vehicle-side control device switches modes, there is no mismatch with the PTO switch.

  As described above, according to the present invention, when the switching time for switching from the electric mode to the PTO mode is longer than the upper limit value after starting the engine restart mode, the power supply from the battery to the electric motor is stopped. As a result, when switching from the electric mode to the PTO mode while the work implement is operating, the operator can work safely and without interruption.

It is a flowchart which shows the power switching control of an electric garbage truck. It is a side view which shows the electric dust collection vehicle which concerns on embodiment of this invention. 1 is a schematic plan view of an electric dust collection vehicle according to the present invention. It is a partial block diagram of the electric garbage collection vehicle which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 2 is a side view of an electric garbage truck 1 as an electric working vehicle according to an embodiment of the present invention. The electric garbage truck 1 performs a base vehicle 10 for traveling and an operation for collecting dust. And a dust collecting device 20 as a bodywork.

  The base vehicle 10 includes a chassis frame 11 and a cab 12 provided at the front portion of the chassis frame 11. The chassis frame 11 is provided with a pair of left and right wheels 11a at the front and a pair of left and right wheels 11b at the rear. A driver seat and a passenger seat are provided inside the cab 12.

  The dust collecting device 20 includes a dust storage box 21 for storing the dust, and a dust input box 22 provided behind the dust storage box 21 for loading the dust into the dust storage box 21. A rectangular dust inlet 22 a is provided at the lower part of the rear surface of the dust inlet box 22. The dust inlet 22a can be opened and closed by a door 22b.

  Inside the dust throwing box 22, there is provided a dust loading device 23 as a working machine for compressing the dust thrown from the dust throwing port 22 a and pushing it into the dust storage box 21. The dust input box 22 is provided with an operation switch 22c as an operation unit for operating the dust loading device 23 adjacent to the dust input port 22a.

  The dust loading device 23 has a rotating plate 23a for scraping the dust thrown in from the dust inlet 22a toward the dust containing box 21 and a pushing plate 23b for pushing the dust picked up by the rotating plate 23a into the dust containing box 21. And have. The rotating plate 23a is driven by a hydraulic motor 23c, and the pushing plate 23b is driven by a swing cylinder 23d.

  FIG. 3 is a schematic plan view of the electric garbage truck 1 according to the present embodiment. The electric garbage truck 1 is mainly attached to the engine E, the transmission T provided behind the engine E, and the transmission T. Furthermore, a PTO (Power take off) device 24 and an electric motor 25 as an electric motor connected to the PTO device 24 by a PTO shaft 28 are provided. In addition, a hydraulic pump 26 that is driven by at least one of the power of the engine E and the power of the electric motor 25 transmitted through the PTO device 24 is provided. The hydraulic pump 26 is connected to the electric motor 25. In the base vehicle 10 of the present embodiment, the power of the electric motor 25 is used only for the hydraulic pump 26 and travels only with the power of the engine.

  FIG. 4 is a partial block diagram of the electric garbage truck 1 according to the present embodiment. The electric garbage truck 1 mainly includes a bodywork battery 13 for driving the dust loading device 23 and an inverter device 27. The electric motor 25 is driven at a predetermined rotational speed by the electric power from the inverter device 27, and the hydraulic pump 26 connected to the electric motor 25 is driven accordingly. The high pressure oil of the hydraulic pump 26 is supplied to the hydraulic motor 23c, the swing cylinder 23d, etc. via the accumulator 41 and the control valve 42, and these hydraulic actuators 23c, 23d are driven. The hydraulic oil is returned to the hydraulic oil tank 43, and the hydraulic oil that has passed through the suction filter 44 is supplied to the hydraulic pump 26 again. Although not shown, the electric motor 25 may be provided between the clutch C and the transmission T.

  The power of the engine E is transmitted to the PTO device 24 via the clutch C and the transmission T. When the PTO device 24 is in the connected state (on state), the power transmitted to the PTO device 24 is transmitted to the hydraulic pump 26 via the PTO shaft 28 and the electric motor 25. When the power of the engine E is transmitted to the hydraulic pump 26, the electric motor 25 basically idles as the PTO shaft 28 rotates. On the other hand, during traveling in which the PTO device 24 is in a disconnected state (off state), the driving force of the transmission T is transmitted to the wheels 11b via the differential (differential gear) 40.

  As described above, the hydraulic pump 26 can be driven in the following state. Specifically, the PTO mode that is directly driven by the power from the engine E via the PTO device 24, the electric mode that is driven by the power from the electric motor 25 that is mainly driven by the power of the battery 13, and the engine Switching between the E mode and the simultaneous mode driven by the power from the electric motor 25 is possible. Further, an engine restart mode is provided between the electric mode and the PTO mode.

  As shown in FIG. 4, the electric garbage truck 1 serves as a vehicle-side control device 30 that controls the base vehicle 10 and a body-side control device that controls the dust collection device 20 mounted on the vehicle. PLC (programmable logic controller) 31.

  The vehicle-side control device 30 plays a role of controlling the entire electric system of the base vehicle 10 including engine control and air-conditioner control. The vehicle-side control device 30 is a PTO mode in which the hydraulic pump 26 is driven by the PTO device 24, electric The motor 25 can be switched to an electric mode in which the hydraulic pump 26 is driven or an engine restart mode.

  That is, the vehicle-side control device 30 starts the engine E when the engine E is stopped and in the electric mode when the charging rate of the battery 13 is smaller than the lower limit value, and switches the engine restart mode from the electric mode to the PTO mode. Configured to do.

  Moreover, the vehicle side control apparatus 30 has the timer 33 which measures the switching time which switches from electric mode to PTO mode after starting engine restart mode, and the switching time which the timer 33 measured is longer than an upper limit. In this case, the power supply from the battery 13 to the electric motor 25 is stopped. In the present embodiment, the power supply from the battery 13 to the electric motor 25 is stopped by turning off the power of the PLC 31. Note that the power source of the PLC 31 in the present embodiment is not the battery 13 but an auxiliary battery (not shown) provided separately for driving the auxiliary machine of the base vehicle 10.

  The PTO switch 32 for setting the PTO mode is a momentary switch that self-resets after being pressed regardless of the PTO mode or the electric mode. The PTO switch 32 is provided in the cab 12, for example, as shown in FIG.

  By configuring as described above, the engine E is automatically started when the charging rate (SOC) of the battery 13 is smaller than the lower limit value, so that the operator's hand is not bothered. If, for some reason, it takes longer than the upper limit value to switch from the electric mode to the PTO mode even though the SOC is lower than the lower limit value, the battery 13 may run out. In the present embodiment, since the power supply to the electric motor 25 is forcibly stopped, it is possible to reliably prevent the battery from running out. In the case of the electric garbage truck 1, even if the electric power supply to the electric motor 25 is stopped and the emergency stop is performed, the garbage loading device 23 and the like are different from those in which an operator rides like an aerial work vehicle. Since it only stops at a predictable timing, the safety of workers is ensured.

  Further, if the PTO switch 32 is an alternate type switch as in the prior art, the body side repeats stopping and driving while the PTO switch 32 is physically kept on, so the mode is automatically switched to the PTO mode. In such a case, there is a problem that a situation may occur in which the state of the PTO switch 32 does not match the actual mode.

  However, in this embodiment, the PTO switch 32 is a momentary switch that is a so-called rebound switch. Therefore, even after the operation, the state returns to the state before pressing, and even if the vehicle-side control device switches the mode, the PTO switch 32 does not match. Will not occur.

  Next, the operation of the electric garbage truck according to this embodiment will be described.

  As shown in FIG. 1, first, in step S01, for example, the operator operates the controller to stop the engine E, and in step S02, the electric mode is set.

  Next, in step S03, the vehicle-side control device 30 determines whether the charging rate (SOC) is equal to or higher than A%. If it is more than A%, it will progress to step S04, will supply power from the battery 13 to the bodywork side, will return to S02 again, and will maintain an electric mode.

  On the contrary, if the SOC is smaller than A%, the battery 13 is not sufficiently charged, and the process proceeds to step S05. Note that the value of A is not particularly limited, and may be, for example, 10 to 30%.

  In step S05, the vehicle-side control device 30 automatically starts the engine E, starts measuring with a timer, and starts measuring the mode switching time.

  Next, in step S06, the vehicle-side control device 30 switches to the PTO mode, ends the timer measurement, and then determines in step S07 whether the switching time is shorter than T seconds. If it is shorter than T seconds, there is no abnormality, so the process proceeds to step S08, and the driving on the bodywork side is continued in the PTO mode. Note that the length of the switching time used as a criterion may be shorter than T seconds or longer than T seconds.

  On the contrary, if the length is equal to or longer than T seconds, the vehicle-side control device 30 determines that there is some abnormality, and stops supplying the bodywork-side power supply in step S09. Specifically, power supply to the PLC 31 from the battery 13 or a vehicle battery (not shown), a generator, or the like is stopped. Thereby, the driving of the swing cylinder 23d and the hydraulic motor 23c is stopped, and the operation of the dust loading device 23 is stopped. In addition, the value of T is not specifically limited, For example, what is necessary is just to be 0.5 to 2 second.

  In step S10, after the charging operation of the battery 13 and other abnormalities are resolved, in step S11, the supply of the power for the bodywork is started again. Specifically, the supply of power from the battery 13 or the like to the PLC 31 is resumed. Next, in step S12, the input to the bodywork side by the hydraulic motor 23c or the like is waited. If there is an input, the operation of the dust loading device 23 or the like is resumed. For this reason, since the dust loading device 23 which is in operation does not stop once and then suddenly starts to move, the problem that the operator cannot cope with the unexpected movement does not occur.

  Therefore, according to the electric garbage truck 1 according to the present embodiment, when switching from the electric mode when the dust loading device 23 is operating to the PTO mode, the worker can work safely without interruption as much as possible. it can.

  In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or a use.

  For example, in the above embodiment, the dust loading device 23 is a rotary type, but may be a so-called press type or planetary gear type.

  In the above embodiment, the electric work vehicle is an electric garbage truck, but is not limited to this, and the present invention can be applied to any work vehicle that works with hydraulic pressure generated by a hydraulic pump driven by an electric motor. .

1 Electric garbage truck (electric work vehicle)
DESCRIPTION OF SYMBOLS 10 Base vehicle 11 Chassis frame 11a Wheel 11b Wheel 12 Cab 13 Battery 20 Dust collection device 21 Dust storage box 22 Dust input box 22a Dust input port 22b Door 22c Operation switch 23 Dust loading device (work machine)
23a Rotating plate 23b Pushing plate 23c Hydraulic motor 23d Oscillating cylinder 24 PTO device 25 Electric motor 26 Hydraulic pump 27 Inverter device 28 PTO shaft 30 Vehicle side control device (control device)
31 PLC (Bodyworking side control device (control device))
32 PTO switch 41 Accumulator 42 Control valve 43 Hydraulic oil tank 44 Suction filter C Clutch E Engine T Transmission

Claims (4)

Engine,
A PTO driven by the engine;
Battery,
An electric motor driven by the electric power of the battery;
A hydraulic pump driven by the PTO or the electric motor;
A working machine driven by the hydraulic pump;
In an electric work vehicle comprising a control device for switching to a PTO mode for driving the hydraulic pump with the PTO or an electric mode for driving the hydraulic pump with the electric motor,
An engine restart mode controlled by the control device is provided between the electric mode and the PTO mode,
In the engine restart mode, when the engine is stopped and the work machine is operating in the electric mode, the engine is started when the charge rate of the battery is smaller than a lower limit value. Configured to switch to mode,
The control device includes a timer for measuring a switching time for switching from the electric mode to the PTO mode after starting the engine restart mode, and when the switching time measured by the timer is longer than an upper limit value, An electric work vehicle configured to stop power supply from a battery to the electric motor. In the electric work vehicle according to claim 1,
The control device
A vehicle-side control device for controlling the vehicle;
A body side control device for controlling the body mounted on the vehicle,
An electric work vehicle configured to stop power supply from the battery to the electric motor by turning off the power of the bodywork side control device. In the electric work vehicle according to claim 2,
The electric work vehicle, wherein the PTO switch for switching to the PTO mode is a momentary switch that self-resets after being pressed regardless of the PTO mode or the electric mode. Engine,
A PTO driven by the engine;
Battery,
An electric motor driven by the electric power of the battery;
A hydraulic pump driven by the PTO or the electric motor;
A working machine driven by the hydraulic pump;
In a control device provided in an electric work vehicle equipped with
The PTO mode is configured to switch to the PTO mode in which the hydraulic pump is driven by the PTO or the electric mode in which the hydraulic pump is driven by the electric motor, and the engine restart mode is executed between the electric mode and the PTO mode. Configured,
In the engine restart mode, when the engine is stopped and the work machine is operating in the electric mode, the engine is started when the charge rate of the battery is smaller than a lower limit value. Configured to switch to mode,
A timer for measuring a switching time for switching from the electric mode to the PTO mode after starting the engine restart mode is provided, and when the switching time measured by the timer is longer than an upper limit value, from the battery to the electric motor. The control device is configured to stop the power supply of.