JP7544540B2 - Work vehicles - Google Patents

Description

The present invention relates to a work vehicle.

For example, Patent Document 1 discloses a refuse collection vehicle equipped with a battery, an inverter, an electric motor, a hydraulic pump, and a hydraulic cylinder. When driving the hydraulic cylinder of this refuse collection vehicle, the inverter powered by the battery is controlled to drive the electric motor, and the rotation of the electric motor is transmitted to the hydraulic pump to rotate the hydraulic pump. The hydraulic valve in the hydraulic circuit is then switched to generate a flow of hydraulic oil in the hydraulic circuit, thereby driving the hydraulic cylinder.

JP 2009-262759 A

In a refuse collection vehicle like the one described above, preparatory control, such as preparing to start up the inverter, is performed for a few seconds before the hydraulic cylinder is driven. During this preparatory control, the electric motor is stopped, so no hydraulic oil is discharged from the hydraulic pump. However, if the operation switch to drive the hydraulic cylinder is operated during preparatory control, the hydraulic valve is switched without hydraulic pressure being applied to the hydraulic circuit, and there is a risk that the hydraulic cylinder will start moving due to its own weight, etc.

The present invention was made in consideration of these circumstances, and aims to provide a work vehicle that can prevent the hydraulic actuator from starting to move even if the operation switch is operated during preparatory control.

(1) The present invention is a work vehicle that includes an electric motor, an inverter that drives and controls the electric motor, a hydraulic pump that discharges hydraulic oil by driving the electric motor, a hydraulic actuator that is driven by the hydraulic oil supplied by the hydraulic pump, a hydraulic valve that switches the supply and discharge of hydraulic oil to the hydraulic actuator, an operation switch that outputs an operation command to drive the hydraulic actuator, and a control unit that performs switching control of the hydraulic valve based on the operation command, and the control unit determines whether preparatory control, including preparation for starting the inverter, is being performed at the time the operation command is input, and does not perform the switching control if it is determined that the preparatory control is being performed.

According to the present invention, when preparatory control, including preparation for inverter startup, is being performed, even if an operation command to drive the hydraulic actuator is output by the operation switch, the control unit does not perform switching control of the hydraulic valve. Therefore, even if the operation switch is operated during preparatory control, it is possible to prevent the hydraulic actuator from starting to move.

(2) It is preferable that the control unit determines that the preparatory control is being performed when a predetermined time has not elapsed since the start of the preparatory control.
In this case, the control unit can easily determine whether or not the preparatory control is being performed.

(3) When the control unit determines that the preparatory control is being performed, it further determines whether the preparatory control has been completed, and if it determines that the preparatory control has been completed and the operation command has been input at the time the preparatory control is completed, it is preferable that the control unit does not perform the switching control.
In this case, when the preparatory control is completed, even if an operation command for driving the hydraulic actuator is output from the operation switch, the control unit will not perform switching control of the hydraulic valve. In other words, unless an operation command for driving the hydraulic actuator is output again from the operation switch after the preparatory control is completed, the control unit will not perform switching control of the hydraulic valve. This makes it possible to prevent the hydraulic actuator from being driven at a timing unintended by the operator.

(4) When the control unit determines that the preparatory control is being performed, it may further determine whether the preparatory control has been completed, and when it determines that the preparatory control has been completed and the operation command has been input at the time the preparatory control is completed, it may perform the switching control.
In this case, the hydraulic actuator can be driven immediately when the preparation control is completed, so that the loading and unloading of rubbish can be carried out quickly.

(5) When the control unit determines that the preparatory control is being performed, it is preferable that the control unit further determines whether the preparatory control has been completed, and when it determines that the preparatory control has been completed, it outputs a notification command to notify the outside.
In this case, the output notification command notifies the outside, so that an operator or the like can easily know that the preparatory control has been completed.

(6) It is preferable that the control unit determines that the preparatory control is completed when a predetermined time has elapsed since the preparatory control was started.
In this case, the control unit can easily determine whether or not the preparatory control has been completed.

According to the present invention, even if the operation switch is operated during preparation control, the hydraulic actuator can be prevented from starting to move.

1 is a side cross-sectional view of a refuse collection vehicle which is a work vehicle according to an embodiment of the present invention. FIG. 1 is a schematic side view of a garbage collection vehicle showing an operating sequence when discharging garbage. FIG. FIG. 1 is a hydraulic circuit diagram of a garbage collection vehicle. FIG. 4 is a front view of a switch box in the cab. FIG. 1 is an electrical circuit diagram of a garbage collection vehicle. FIG. 2 is a block diagram of a refuse collection vehicle. 4 is a time chart showing an example of a control process by a control unit. 10 is a time chart showing a modified example of the control process by the control unit.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
[Overall configuration]
Fig. 1 is a side cross-sectional view of a work vehicle according to an embodiment of the present invention. In Fig. 1, the work vehicle of this embodiment is composed of a refuse collection vehicle 1 with a refuse collection device (work device) mounted on a vehicle body 10 behind a driver's cab 1a. The vehicle body 10 has a chassis frame 11 and a subframe 12 mounted on and fixed to the chassis frame 11.

The refuse collection vehicle 1 is equipped with, as the refuse collection equipment, a refuse storage box 2 mounted on a subframe 12, and a refuse drop box 3 provided adjacent to the rear of the refuse storage box 2. An opening 2a is formed on the rear surface of the refuse storage box 2. An input port 3a through which the refuse is input is formed on the rear of the refuse input box 3, and a lid 3b is provided which slides up and down to open and close the input port 3a. An opening 3d is provided on the lower front part of the refuse input box 3 for storing the refuse inputted into the refuse input box 3 in the refuse storage box 2.

The trash bin 3 can rotate around a fulcrum 3f provided at the top, which allows it to open and close relative to the trash storage box 2. The trash bin 3 can rotate between a closed position in which it closes the opening 2a of the trash storage box 2 as shown by the solid line in FIG. 1, and an open position in which it can open the opening 2a by rotating upward as shown by the two-dot chain line in FIG. 1, allowing trash to be discharged.

Next, the loading device T provided in the trash bin 3 will be described. The cylinder side base end 112a of a push cylinder (hydraulic actuator) 112 is axially attached to the left and right side walls 3c of the trash bin 3, allowing the push cylinder 112 to rotate. In addition, a push plate 108 is attached to the left and right side walls 3c so that it can rotate around a support shaft 113. The push plate 108 is integrated by connecting the left and right members with side shapes as shown in the figure with a plate or the like (not shown) that extends in the vehicle width direction.

The upper end of the pushing plate 108 and the tip of the piston rod of the pushing cylinder 112 are connected to each other by a pin 114, so that when the pushing cylinder 112 is driven to extend, the pushing cylinder 112 itself rotates in the counterclockwise direction in the figure, causing the pushing plate 108 to rotate in the clockwise direction in FIG. 1, resulting in the state shown by the solid line in FIG. 1. Also, when the pushing cylinder 112 is driven to retract from that state, the pushing cylinder 112 itself rotates in the clockwise direction in FIG. 1, causing the pushing plate 108 to rotate in the counterclockwise direction in FIG. 1, resulting in the state shown by the two-dot chain line in FIG. 1.

A rotating plate 115, which has the side shape shown in the figure and extends in the width direction of the vehicle, is attached to the left and right side walls 3c so as to be rotatable around a support shaft 116. The normal rotation direction of the rotating plate 115 is clockwise in the figure. The inner bottom surface 3e of the trash bin 3 is formed in an arc shape that follows the rotation trajectory of the tip of the rotating plate 115.

In the loading device T configured as described above, when trash is thrown into the trash bin 3, the rotating plate 115 rises to the illustrated position (9 o'clock position) while swirling the trash. Then, when the rotating plate 115 reaches the illustrated position, the pushing plate 108 rotates clockwise in FIG. 1 from the position indicated by the two-dot chain line to the position indicated by the solid line, and pushes the trash on the rotating plate 115 into the trash storage box 2. The pushing plate 108 then starts to rotate counterclockwise in FIG. 1 when the rotating plate 115 passes the 12 o'clock position, and returns to its original position (the position indicated by the two-dot chain line) before the next pushing operation begins. By performing such periodic operations in one cycle or continuous cycles, the loading operation of loading trash into the trash storage box 2 can be performed.

On the other hand, a dump cylinder (hydraulic actuator) 119 is provided below the garbage storage box 2, and its cylinder side base end 119a is axially attached to the subframe 12. Also, the piston rod side tip 119b is axially attached to the underside of the garbage storage box 2. The lower rear end of the garbage storage box 2 is supported on the subframe 12 via a support shaft 120 so that it can rotate up and down. By driving the dump cylinder 119 to extend and retract, the garbage storage box 2 can be rotated up and down between the tilted position shown in FIG. 3(c) and the landing position shown in FIG. 3(a). Therefore, the garbage loaded into the garbage storage box 2 is discharged to the outside from the opening 2a by its own weight by driving the dump cylinder 119 to extend and rotate (tilt) the garbage storage box 2 upward relative to the vehicle body 10.

Figure 2 is a rear view of the garbage collection vehicle 1. A pair of swing cylinders (hydraulic actuators) 20, arranged on both the left and right ends of the garbage bin 3, have their upper ends attached to the garbage storage bin 2 and their lower ends attached to the garbage bin 3. When the swing cylinders 20 are extended, the garbage bin 3 is rotated upward (opened) (see Figure 3(b)), and when they are contracted, the garbage bin 3 is rotated downward (closed) (see Figure 3(a)).

With the above configuration, when performing the discharge operation of discharging the garbage loaded in the garbage storage box 2 to the outside from the traveling state shown in FIG. 3(a) (the garbage dump box 3 is in the closed position and the garbage storage box 2 is in the landing position), the swing cylinder 20 is first extended to rotate the garbage dump box 3 upward. As a result, the garbage dump box 3 reaches the open position as shown in FIG. 3(b). From this state, the dump cylinder 119 is extended and rotated to rotate the garbage storage box 2 upward from the landing position. As a result, the garbage storage box 2 is rotated upward to the tilted position as shown in FIG. 3(c), and the garbage in the garbage storage box 2 is discharged to the outside from the opening 2a by its own weight.

[Hydraulic circuit]
4 is a hydraulic circuit diagram relating to the push cylinder 112, dump cylinder 119, swing cylinder 20, and hydraulic motor (hydraulic actuator) 117. This hydraulic circuit is configured by connecting an oil tank 21, a hydraulic pump 22, a first hydraulic valve 124, a second hydraulic valve 125, a third hydraulic valve 126, a fourth hydraulic valve 127, a pair of fifth hydraulic valves 128, a tailgate lock cylinder (hydraulic actuator) 31, and other pressure control valves 196-199, check valves 129a-129g, a filter 130, etc. as shown in the figure.

The hydraulic motor 117 rotates the rotating plate 115 and drives the loading device T together with the pushing cylinder 112. An electric motor 23 is connected to the hydraulic pump 22, and the electric motor 23 drives the hydraulic pump 22 to discharge hydraulic oil, thereby driving the pushing cylinder 112, dump cylinder 119, swing cylinder 20, and hydraulic motor 117. Therefore, the electric motor 23 constitutes part of the work drive unit D2 that drives the waste collection equipment (work equipment).

The first to fourth hydraulic valves 124 to 127 each include a three-position solenoid valve. The pair of fifth hydraulic valves 128 each include a two-position solenoid valve.
The first hydraulic valve 124 switches between supplying and discharging hydraulic oil to the pushing cylinder 112. When the solenoid 124s of the first hydraulic valve 124 is excited, the pushing cylinder 112 is driven to contract, and when the solenoid 124e is excited, the pushing cylinder 112 is driven to extend.

The second hydraulic valve 125 switches the supply and discharge of hydraulic oil to the hydraulic motor 117. When the solenoid 125n of the second hydraulic valve 125 is excited, the hydraulic motor 117 rotates forward and the rotating plate 115 rotates clockwise in FIG. 1. When the solenoid 125r of the second hydraulic valve 125 is excited, the hydraulic motor 117 rotates reverse and the rotating plate 115 rotates counterclockwise in FIG. 1.

The third hydraulic valve 126 switches between supplying and discharging hydraulic oil to the dump cylinder 119. When a solenoid 126s of the third hydraulic valve 126 is excited, the dump cylinder 119 is driven to contract, and when a solenoid 126e is excited, the dump cylinder 119 is driven to extend.
The fourth hydraulic valve 127 switches between supplying and discharging hydraulic oil to the tailgate lock cylinder 31 and the swing cylinder 20. The fifth hydraulic valve 128 switches between supplying and discharging hydraulic oil to the swing cylinder 20.
Supply and discharge switching refers to switching each hydraulic valve 124-127 between a supply state in which hydraulic actuators 20, 31, 112, 117, 119 communicate with hydraulic pump 22 and/or oil tank 21 to allow hydraulic oil to flow between them, and a cut-off state in which hydraulic oil flow is cut off. When each hydraulic valve 124-127 is in the supply state, hydraulic pump 22 is driven, or actuators 20, 31, 112, 117, 119 are driven by the weight of each part, and work equipment (loading device T and trash collection box 2) is operated.

When the trash bin 3 is in the closed position (solid line in FIG. 1), the swing cylinder 20 is in its most contracted state, and the fourth hydraulic valve 127 is in its neutral position. Also, each of the fifth hydraulic valves 128 is in the position shown in FIG. 4. When the solenoid 127e of the fourth hydraulic valve 127 is excited from this state, the tailgate lock cylinder 31 is driven in the unlocking direction, and the swing cylinder 20 is driven to extend, causing the trash bin 3 to rotate upward.

When the solenoid 127e of the fourth hydraulic valve 127 is demagnetized and the solenoid 128e of each fifth hydraulic valve 128 is energized, the hydraulic oil in each swing cylinder 20 is returned to the oil tank 21 via the fifth hydraulic valve 128 and the fourth hydraulic valve 127 due to the weight of the garbage bin 3. This causes each swing cylinder 20 to contract and the garbage bin 3 to rotate downward. In addition, after the garbage bin 3 reaches the closed position, when the solenoid 127s of the fourth hydraulic valve 127 is energized, the tailgate lock cylinder 31 is driven in the lock direction and the garbage bin 3 is locked in the closed position. After that, the solenoid 127s is demagnetized, but the check valve 129g restricts the tailgate lock cylinder 31 from being driven in the unlock direction, so the garbage bin 3 is maintained locked in the closed position.

[Switch box]
5 is a front view of the switch box SB1 provided in the driver's cab 1a. The switch box SB1 is provided with a main switch 34, an ejection switch 35, a scraping switch 37, a main lamp 38, a lock lamp 39, and a preparation completion lamp 40.
The main switch 34 is a switch that can select one of the positions "load", "OFF", and "discharge" and is held in the selected position even when released. The discharge switch 35 is a switch that can select one of the positions "discharge", "OFF", and "return" and is returned to the "OFF" position when released.

When the main switch 34 is switched to "loading", the operation of the first and second hydraulic valves 124, 125 is permitted, thereby permitting the driving of the push cylinder 112 and the hydraulic motor 117, and the operation of the third and fourth hydraulic valves 126, 127 is restricted, thereby restricting the driving of the dump cylinder 119 and the swing cylinder 20. This allows the operation of switches 42 to 44 of the switch boxes SB2, SB3, which will be described later.
On the other hand, when the main switch 34 is switched to "discharge", the operation of the third and fourth hydraulic valves 126, 127 is permitted, thereby permitting the driving of the dump cylinder 119 and the swing cylinder 20, and the operation of the first and second hydraulic valves 124, 125 is restricted, thereby restricting the driving of the push cylinder 112 and the hydraulic motor 117. This allows the switching operation of the discharge switch 35. At that time, the discharge switch 35 functions as an operation switch that outputs operation commands to respectively drive the tailgate lock cylinder 31, the swing cylinder 20, and the dump cylinder 119.

Specifically, when the discharge switch 35 is switched to "discharge" with the main switch 34 switched to "discharge", the solenoid 127e of the fourth hydraulic valve 127 is excited, and then the solenoid 126e of the third hydraulic valve 126 is excited. As a result, as shown in the order of Figures 3(a) to (c), the tailgate lock cylinder 31 is driven in the unlocking direction, the swing cylinder 20 is extended, and the trash bin 3 is rotated upward, and then the dump cylinder 119 is automatically extended, and the trash storage bin 2 is rotated upward to the tilted position.

When the discharge switch 35 is switched to "return" from this state, the solenoid 126s of the third hydraulic valve 126 is excited, the solenoid 127e of the fourth hydraulic valve 127 is de-energized, and the fifth hydraulic valve 128 is excited. As a result, as shown in the order of Figures 3(c) to (a), the dump cylinder 119 is contracted and the garbage container 2 rotates downward to the landing position under its own weight, and then the swing cylinder 20 is automatically contracted and the garbage dump box 3 rotates downward. Then, when the garbage dump box 3 rotates downward to the closed position, the solenoid 127s of the fourth hydraulic valve 127 is automatically excited. As a result, the tailgate lock cylinder 31 is driven in the lock direction and the garbage container 2 is locked in the closed position.

The clearing switch 37 is a type of switch that can select either "automatic" or "manual" and can be held in the selected position even when released. When the clearing switch 37 is set to "automatic," rotating the trash bin 3 to the upper rotation position automatically performs an operation similar to loading, allowing any trash remaining in the trash bin 3 to be removed.

The main lamp 38 is turned on when each switch of the switch box SB1 can be operated. The lock lamp 39 is turned on when the tailgate lock cylinder 31 is in the locked state. The preparation complete lamp 40 is turned on when the preparation control described below is completed.

In FIG. 2, switch boxes SB2 and SB3 are provided at the rear of both left and right side walls 3c of the trash bin 3. In this embodiment, switch box SB2 is provided on the side wall 3c on the left side of the figure, and switch box SB3 is provided on the side wall 3c on the right side of the figure. Each switch of switch boxes SB2 and SB3 becomes operable when the main switch 34 is switched to "loading" as described above.

On the side of the switch box SB2, there is provided an operation selection switch 42 for selecting either the "continuous cycle" or "single cycle" operation mode for the operation of the push plate 108 and the rotating plate 115. On the front of the switch box SB2, there is provided a loading switch 43 for starting the loading operation in each operation mode, and a stop switch 44 for stopping the continuous cycle operation. The stop switch 44 is also provided on the switch box SB3.

The loading switch 43 functions as an operation switch that outputs operation commands for driving the pushing cylinder 112 and the hydraulic motor 117. When the loading switch 43 is turned on, the solenoid 125n of the second hydraulic valve 125 is excited, and then the solenoids 124s, 124e of the first hydraulic valve 124 are alternately and repeatedly excited at a predetermined timing. As a result, as shown in FIG. 1, the hydraulic motor 117 is driven in the forward direction to rotate the rotating plate 115, and the pushing cylinder 112 is repeatedly driven to contract and expand, thereby rotating the pushing plate 108 back and forth.
The other switches are switches to be used only in emergencies, and detailed explanations thereof will be omitted.

[Battery]
In Fig. 1, the refuse collection vehicle 1 is an EV vehicle that runs by driving an electric motor 5 (see Fig. 6) of a vehicle running drive unit D1 using a battery 4 mounted on a subframe 12 in the cab back space S (between the driver's cab 1a and the refuse collection box 2) as a power source. This battery 4 also serves as a power source for the electric motor 23 (work drive unit D2) that drives the refuse collection equipment. The battery 4 in this embodiment is detachably attached to the subframe 12, and is charged by removing it from the subframe 12 and connecting it to an external charging device (not shown).

[Electric circuit]
Fig. 6 is an electrical circuit diagram of the sewage collection vehicle 1. In Fig. 6, a first positive electric circuit Lp1 and a first negative electric circuit Ln1 are connected to a battery 4 (having a voltage of, for example, 400V). A branch circuit 50 is connected to the downstream ends of the first positive electric circuit Lp1 and the first negative electric circuit Ln1. The branch circuit 50 has three positive connection ends 51p, 52p, 53p and three negative connection ends 51n, 52n, 53n.

The first positive side electrical circuit Lp1 and the first negative side electrical circuit Ln1 are connected to the positive side connection end 51p and the negative side connection end 51n, respectively. The positive side connection end 51p functions as an input end to which power is input from the battery 4 via the first positive side electrical circuit Lp1. The other two positive side connection ends 52p, 53p function as output ends that branch and output the power input from the positive side connection end 51p.

A second positive side electric circuit Lp2 and a second negative side electric circuit Ln2 are connected to the positive side connection terminal 52p and the negative side connection terminal 52n, respectively, and a vehicle driving drive unit D1 is connected to each downstream end of these electric circuits Lp2, Ln2.
A third positive electric circuit Lp3 and a third negative electric circuit Ln3 are connected to the positive connection end 53p and the negative connection end 53n, respectively, and a working drive unit D2 is connected to each downstream end of these electric circuits Lp3 and Ln3. A positive bypass connection point P1 in the third positive electric circuit Lp3 and a negative bypass connection point P2 in the third negative electric circuit Ln3 are connected by a bypass electric circuit L4.

As a result, the branch circuit 50 branches the power input from the battery 4 and outputs it to the vehicle driving drive unit D1 and the work drive unit D2. As a result, the vehicle driving drive unit D1 and the work drive unit D2 are driven by power supplied from the battery 4.

The vehicle driving drive unit D1 includes the electric motor 5 and an inverter 6 that drives and controls the electric motor 5. The inverter 6 is connected to the control unit 90, and is controlled by the control unit 90. The inverter 6 includes a capacitor 6a connected to the second positive side electric circuit Lp2 and the second negative side electric circuit Ln2. The capacitor 6a stores the power to be supplied to the electric motor 5 in order to stably drive the AC electric motor 5.

The working drive unit D2 includes the electric motor 23 and an inverter 24 that drives and controls the electric motor 23. The inverter 24 is connected to the control unit 90 and is controlled by the control unit 90. The inverter 24 includes a capacitor 24a connected to the third positive side electric circuit Lp3 and the third negative side electric circuit Ln3. The capacitor 24a charges the power supplied to the electric motor 23 to stably drive the AC electric motor 23.

A vehicle running relay circuit 60 capable of opening and closing the first positive side electric circuit Lp1 and the first negative side electric circuit Ln1 is provided in the middle of the first positive side electric circuit Lp1 and the first negative side electric circuit Ln1. In this embodiment, the vehicle running relay circuit 60 includes a first relay 61, a second relay 62, a third relay 63, and a limiting resistor 64.

The first relay 61 is provided in the middle of the first positive side electrical circuit Lp1. The limiting resistor 64 and the second relay 62 are connected in parallel to the first relay 61 in the middle of the first positive side electrical circuit Lp1, and are connected in series with each other in this order from the upstream side (the battery 4 side; the same applies below). The first and second relays 61, 62 are configured to open and close the first positive side electrical circuit Lp1. The third relay 63 is provided in the middle of the first negative side electrical circuit Ln1, and is configured to open and close the electrical circuit Lp1. The first to third relays 61 to 63 are connected to the control unit 90, and are controlled to open and close by the control unit 90.

[Vehicle running relay circuit]
In the vehicle running relay circuit 60, when the vehicle power switch 45 (see Figure 7) provided in the driver's cab 1a is turned on, the control unit 90 performs a first power supply control in which each relay 61 to 63 is opened and closed to supply power from the battery 4 to the vehicle running drive unit D1.
Specifically, when the power switch 45 is turned on, the vehicle running relay circuit 60 is controlled by the control unit 90 to change from a state in which the relays 61 to 63 are all open to a state in which the third relay 63 is closed and then the second relay 62 is closed.

Then, a power path is formed from the positive side of the battery 4 through the first positive side electrical circuit Lp1 (limiting resistor 64, closed second relay 62), the branch circuit 50 (positive side connection terminals 51p, 52p), the second positive side electrical circuit Lp2, the inverter 6 (capacitor 6a), the second negative side electrical circuit Ln2, the branch circuit 50 (negative side connection terminals 52n, 51n), the first negative side electrical circuit Ln1 (closed third relay 63), and back to the battery 4. This starts charging the capacitor 6a of the inverter 6.

When the time required for charging of the capacitor 6a to be completed after closing the second relay 62 has elapsed, the vehicle running relay circuit 60 is then controlled by the control unit 90 to close the first relay 61 and then open the second relay 62.

Then, an electric power path is formed from the positive side of the battery 4 through the first positive side electric circuit Lp1 (closed first relay 61), the branch circuit 50 (positive side connection terminals 51p, 52p), the second positive side electric circuit Lp2, the inverter 6 (capacitor 6a), the second negative side electric circuit Ln2, the branch circuit 50 (negative side connection terminals 52n, 51n), the first negative side electric circuit Ln1 (closed third relay 63), and back to the battery 4. As a result, the first positive side electric circuit Lp1 and the first negative side electric circuit Ln1 are closed, and electric power is stably supplied from the battery 4 to the electric motor 5 of the vehicle driving drive unit D1.

[Working relay circuit]
A working relay circuit 70 capable of opening and closing the third positive electric circuit Lp3 and the third negative electric circuit Ln3 is disposed in the middle of the third positive electric circuit Lp3 and the third negative electric circuit Ln3. The working relay circuit 70 of this embodiment includes a first relay 71, a second relay 72, a third relay 73, a fourth relay 74, a fifth relay 75, a fuse 76, and a limiting resistor 77.

The fuse 76 and the first relay 71 are connected in series in this order from the upstream side upstream of the positive bypass connection point P1 of the third positive side electrical circuit Lp3. The second relay 72 and the limiting resistor 77 are connected in series in this order from the upstream side downstream (the capacitor 24a side; the same applies below) of the positive bypass connection point P1 of the third positive side electrical circuit Lp3. Note that the second relay 72 and the limiting resistor 77 may also be connected in series in this order from the downstream side.

The third relay 73 is connected in series to the first relay 71 downstream of the positive side bypass connection point P1 in the third positive side electrical circuit Lp3, and is connected in parallel to the second relay 72 and the limiting resistor 77. As a result, the positive side bypass connection point P1 is located between the first relay 71 and the parallel connection point P3 upstream of the second relay 72 and the third relay 73. The first to third relays 71 to 73 are configured to open and close the third positive side electrical circuit Lp3.

The fourth relay 74 is provided upstream of the negative side bypass connection point P2 of the third negative side electric circuit Ln3 and is configured to open and close the electric circuit Ln3. The fifth relay 75 is provided midway along the bypass electric circuit Lb10 and is configured to open and close the electric circuit Lb10. The first to fifth relays 71 to 75 are connected to the control unit 90 and are controlled to be opened and closed by the control unit 90.

In the working relay circuit 70, after the above-mentioned first power supply control is performed, that is, when it becomes possible to supply power from the battery 4 to the third positive side electrical circuit Lp3 and the third negative side electrical circuit Ln3 via these electrical circuits Lp1, Ln1 and the branch circuit 50, the control unit 90 performs a second power supply control in which the relays 71 to 75 are opened and closed to supply power from the battery 4 to the working drive unit D2.

Specifically, with the first positive side electric circuit Lp1 and the first negative side electric circuit Ln1 closed, the working relay circuit 70 is controlled by the control unit 90 to close the fourth relay 74 and the second relay 72 in that order, from a state in which the relays 71 to 75 are all open, and then close the first relay 71.

Then, a power path is formed from the positive side of the battery 4 through the first positive side electrical circuit Lp1 (closed first relay 61), the branch circuit 50 (positive side connection terminals 51p, 53p), the third positive side electrical circuit Lp3 (fuse 76, closed first relay 71 and second relay 72, limiting resistor 77), the inverter 24 (capacitor 24a), the third negative side electrical circuit Ln3 (closed fourth relay 74), the branch circuit 50 (negative side connection terminals 53n and 51n), the first negative side electrical circuit Ln1 (closed third relay 63), and back to the battery 4. This starts charging the capacitor 24a of the inverter 24.

When the time required for charging of the capacitor 24a to be completed has elapsed since the first relay 71 was closed, the control unit 90 then controls the working relay circuit 70 to close the third relay 73 and then open the second relay 72.

Then, a power path is formed from the positive side of the battery 4 through the first positive side electrical circuit Lp1 (closed first relay 61), the branch circuit 50 (positive side connection terminals 51p, 53p), the third positive side electrical circuit Lp3 (fuse 76, closed first relay 71 and third relay 73), the inverter 24 (capacitor 24a), the third negative side electrical circuit Ln3 (closed fourth relay 74), the branch circuit 50 (negative side connection terminals 53n and 51n), the first negative side electrical circuit Ln1 (closed third relay 63), and back to the battery 4. As a result, the third positive side electrical circuit Lp3 and the third negative side electrical circuit Ln3 are closed, and power is stably supplied from the battery 4 to the electric motor 23 of the work drive unit D2.

[Control unit]
Fig. 7 is a block diagram of the sewage collection vehicle 1. In Figs. 6 and 7, the control unit 90 is a microcomputer composed of a CPU, memory, etc. As described above, the control unit 90 controls the operation of the inverter 6 of the vehicle running drive unit D1 and the inverter 24 of the work drive unit D2, and also controls the opening and closing of the relays 61-63 of the vehicle running relay circuit 60 and the relays 71-75 of the work relay circuit 70. The control unit 90 also controls the lighting of the ready lamp 40 and the hazard lamps 13 of the vehicle.

The control unit 90 controls the switching of the first to fifth hydraulic valves 124 to 128 based on operation commands of various switches such as the loading switch 43 and the unloading switch 35 .
Specifically, when an operation command is input to turn on the loading switch 43, the control unit 90 excites the solenoid 125n of the second hydraulic valve 125 and the solenoids 124s, 124e of the first hydraulic valve 124, respectively.

When an operation command is input to switch the discharge switch 35 to "discharge", the control unit 90 excites the solenoid 127e of the fourth hydraulic valve 127 and the solenoid 126e of the third hydraulic valve 126, respectively.
When an operation command is input to switch the discharge switch 35 to “return”, the control unit 90 magnetizes the solenoid 126s of the third hydraulic valve 126 and the fifth hydraulic valve 128, and demagnetizes the solenoid 127e of the fourth hydraulic valve 127.

When the power switch 45 is turned on, the control unit 90 performs preparation control, including checking for faults in various devices in the electric circuit and preparing for startup. The preparation control includes a first preparation control that checks for faults in the relays 61 to 63 and prepares for the startup of the inverter 6, a second preparation control that checks for faults in each of the relays 71 to 75, and a third preparation control that prepares for the startup of the inverter 24.

The fault check is performed, for example, by detecting with a detection means (not shown) whether the electric circuit in which the relay is located is energized when each relay 61-63, 71-75 is closed, and whether the electric circuit in which the relay is located is interrupted (not energized) when each relay 61-63, 71-75 is opened. During the startup preparation, checks are performed to see whether the control unit (not shown) in each inverter 6, 24 is operating normally, etc.

In this embodiment, the control unit 90 performs the first preparation control, the second preparation control, and the third preparation control in that order. Note that the preparation control may include at least the third preparation control.

[Preparation Control]
Fig. 8 is a time chart showing an example of control processing by the control unit 90. In Fig. 6 and Fig. 8, when the power switch 45 is turned on, the control unit 90 starts the first preparation control at the time t0 when the operation signal is input. This causes fault checks of the relays 61 to 63 and preparations for starting the inverter 6 to be performed.

The control unit 90 determines that the first preparation control is completed at time t1, a predetermined time after time t0, and starts the first power supply control from the completion time t1. After that, when the first power supply control is completed and the motor 5 is in a state where it can be started (a state where the vehicle will run when power is supplied to the vehicle driving drive unit D1 based on accelerator operation), the control unit 90 starts the second preparation control from the completion time t2 of the first power supply control. This causes a failure check of the relays 71 to 75.

When the second preparation control is completed, the control unit 90 starts the second power supply control from a completion time t3. When the voltage of the capacitor 24a increases to a voltage equivalent to that of the battery 4 during the second power supply control, the control unit 90 starts the third preparation control from a time t4.
Furthermore, thereafter, when the second power supply control is completed, power is supplied to the work drive unit D2, and from the completion time t5 of the second power supply control, the first to fifth hydraulic valves 124 to 128 can be switched by operating the loading switch 43 or the unloading switch 35 (hereinafter also referred to as the operation switches 43, 35).

The control unit 90 determines that the third preparation control (preparation control) is completed at time t7, when a predetermined time has elapsed since the time t0. Then, at time t8, when a predetermined margin time has elapsed since the time t7, the control unit 90 outputs a notification command to the preparation completion lamp 40 and hazard lamp 13, which are external, and turns on the preparation completion lamp 40 and blinks the hazard lamp 13. The lighting of the preparation completion lamp 40 can notify workers in the cab 1a that the preparation control is completed. The blinking of the hazard lamp 13 can also notify workers outside the vehicle who are performing work such as loading garbage. The control unit 90 may output a notification command to other notification means, such as a buzzer, in addition to the above-mentioned lamps 40 and 13.

[Hydraulic valve switching control]
In Figures 4 and 8, when an operation command is input from the operation switch 43, 35, if preparatory control is being performed at the time of input, the control unit 90 does not perform switching control of the hydraulic valve that is the target of switching of the operation command among the first to fifth hydraulic valves 124-128 (hereinafter referred to as the target hydraulic valve).

The control example of FIG. 8 shows a case where an operation command for the operation switches 43, 35 is input to the control unit 90 twice. The first operation command is input between time t6, when the third preparatory control is in progress, and time t9, which is after time t8, when a predetermined margin time has elapsed since the completion of the third preparatory control. The second operation command is input at time t10, which is after time t9. Below, the process executed by the control unit 90 when an operation command for the operation switches 43, 35 is input will be described based on the control example of FIG. 8.

The control unit 90 performs a first judgment to judge whether or not preparatory control is being performed at time t6 when the first operation command of the operation switches 43, 35 is input. This first judgment is made based on whether or not a predetermined time (t8-t1) has elapsed since time t1 when preparatory control was started. If the predetermined time (t8-t1) has elapsed, the control unit 90 judges that preparatory control is not being performed, and if the predetermined time (t8-t1) has not elapsed, the control unit 90 judges that preparatory control is being performed. In this control example, since the predetermined time (t8-t1) has not elapsed, the control unit 90 judges that preparatory control is being performed.

The control unit 90 determines whether or not to perform switching control of the target hydraulic valve based on the first determination. If the control unit 90 determines that preparatory control is not being performed, it performs switching control of the target hydraulic valve, and if it determines that preparatory control is being performed, it does not perform switching control of the target hydraulic valve. In this control example, the control unit 90 determines that preparatory control is being performed, so it does not perform switching control of the target hydraulic valve. Therefore, at time t6 when the first operation command of the operation switches 43, 35 is input, the target hydraulic valve is not switched and the inverter 24 is not activated.

When the control unit 90 determines in the first determination that preparatory control is being performed, it further performs a second determination to determine whether or not preparatory control has been completed. This second determination, like the first determination, is determined based on whether or not a predetermined time (t8-t1) has elapsed since time t1 when preparatory control was started. The control unit 90 determines that preparatory control has been completed if the predetermined time (t8-t1) has elapsed, and determines that preparatory control has not been completed if the predetermined time (t8-t1) has not elapsed.

When the control unit 90 determines in the second judgment that the preparatory control is not complete, the control unit 90 repeats the second judgment at regular time intervals until it determines that the preparatory control is complete. When the control unit 90 determines in the second judgment that the preparatory control is complete and an operation command for the operation switch 43, 35 is input at the time of completion of the preparatory control, the control unit 90 does not perform switching control of the target hydraulic valve.

In this control example, the control unit 90 determines that the preparatory control is complete because a predetermined time (t8-t1) has elapsed at time t8. The control unit 90 does not perform switching control of the target hydraulic valve because an operation command for the operation switches 43, 35 has been input at time t8 when the preparatory control is completed. Therefore, even if an operation command for the operation switches 43, 35 has been input at time t8 when the preparatory control is completed, the target hydraulic valve will not be switched and the inverter 24 will not be activated.

In the second judgment, it does not matter whether the operation command input at the time t8 when the preparatory control is completed is the same as the operation command at the time t6 when the first judgment is made. Therefore, even if the operation command input at the time t8 when the preparatory control is completed is an operation command different from the operation command at the time t6 (the second or subsequent operation command), the target hydraulic valve will not switch and the inverter 24 will not operate.

The control unit 90 performs the first judgment at time t10 when the second operation command of the operation switches 43, 35 is input. In this control example, since a predetermined time (t8-t1) has elapsed at time t10, the control unit 90 judges in the first judgment that preparatory control is not being performed. The control unit 90 then decides whether or not to perform switching control of the target hydraulic valve based on the first judgment. In this control example, since the control unit 90 has determined that preparatory control is not being performed, it performs switching control of the target hydraulic valve. As a result, the target hydraulic valve is switched at time t10 when the second operation command of the operation switches 43, 35 is input, and the inverter 24 is activated.

According to the garbage collection vehicle 1 of this embodiment configured as described above, when preparatory control including preparation for starting the inverters 6, 24 is being performed, even if an operation command to drive the hydraulic actuators 20, 31, 112, 117, 119 is output by the operation switches 43, 35, the control unit 90 does not perform switching control of the target hydraulic valve. Therefore, even if the operation switches 43, 35 are operated during preparatory control, it is possible to prevent the hydraulic actuators 20, 31, 112, 117, 119 from starting to move due to their own weight (for example, the pushing cylinder 112 from the solid line position in FIG. 1 to the two-dot chain line position due to its own weight).

In addition, in the first determination, the control unit 90 determines that preparatory control is being performed if a predetermined time (t8-t1) has not elapsed since time t6 when preparatory control was started, so that the first determination of whether preparatory control is being performed can be easily made.

In addition, in the second determination, the control unit 90 determines that the preparatory control is completed if a predetermined time has elapsed from the time t6 when the preparatory control was started, so that the second determination of whether or not the preparatory control is completed can be easily performed.

Furthermore, even if an operation command for driving the hydraulic actuators 20, 31, 112, 117, 119 is output by the operation switch 43, 35 at the time when the preparatory control is completed (even if the operation command is continuously output before and after the completion of the preparatory control), the control unit 90 will not perform switching control of the target hydraulic valve. In other words, unless an operation command for driving the hydraulic actuators 20, 31, 112, 117, 119 is output again by the operation switch 43, 35 after the preparatory control is completed (unless the control unit 90 detects the edge at the moment when the operation switch 43, 35 is turned from OFF to ON), the control unit 90 will not perform switching control of the target hydraulic valve. This makes it possible to prevent the target hydraulic valve from being driven at a timing unintended by the operator.

When the control unit 90 determines that the preparation control is complete, it outputs a notification command to the preparation completion lamp 40 and the hazard lamp 13. This causes the preparation completion lamp 40 to light up and the hazard lamp 13 to flash, allowing the worker or the like to easily understand that the preparation control is complete. As a result, the worker or the like can quickly perform the loading and unloading of garbage by immediately operating the operation switches 43, 35 after the preparation control is completed.

[Modification]
FIG. 9 is a time chart showing a modified example of the control process by the control unit 90. In FIG. 6 and FIG. 9, in this modified example, the switching control of the first to fifth hydraulic valves 124 to 128 when an operation command for the operation switches 43, 35 is input is different from the control example (FIG. 8) of the above embodiment. FIG. 9 shows a case where an operation command for the operation switches 43, 35 is input to the control unit 90 only once. The operation command is input from time t6 during the third preparation control to time t9 after time t8 when a predetermined margin time has elapsed since the completion of the third preparation control, as in the first operation command in the above embodiment. Hereinafter, the process executed by the control unit 90 when an operation command for the operation switches 43, 35 is input will be described based on the control example of FIG. 9.

The control unit 90 performs a first determination to determine whether preparatory control is being performed at time t6 when an operation command is input to the operation switches 43, 35. The method of performing the first determination is the same as in the above embodiment. In this modified example, since a predetermined time (t8-t1) has not elapsed since time t1 when preparatory control was started, the control unit 90 determines that preparatory control is being performed.

The control unit 90 determines whether or not to perform switching control of the target hydraulic valve based on the first judgment. The method of this judgment is the same as in the above embodiment. In this modified example, the control unit 90 determines that preparatory control is being performed, and therefore does not perform switching control of the target hydraulic valve. Therefore, at time t6 when an operation command is input for the operation switches 43, 35, the target hydraulic valve does not switch, and the inverter 24 does not operate.

When the control unit 90 determines in the first determination that preparatory control is being performed, it further performs a second determination to determine whether or not the preparatory control has been completed. The method of the second determination is the same as in the above embodiment. When the control unit 90 determines in the second determination that the preparatory control has not been completed, it repeats the second determination at regular time intervals until it determines that the preparatory control has been completed. When the control unit 90 determines in the second determination that the preparatory control has been completed and an operation command for the operation switch 43, 35 has been input at the time of completion of the preparatory control, it performs switching control of the target hydraulic valve.

In this modified example, the control unit 90 determines that the preparatory control is complete because a predetermined time (t8-t1) has elapsed at time t8. The control unit 90 then performs switching control of the target hydraulic valve because an operation command for the operation switches 43, 35 has been input at time t8 when the preparatory control is completed. Therefore, if an operation command for the operation switches 43, 35 has been input at time t8 when the preparatory control is completed, the target hydraulic valve is switched and the inverter 24 is activated.

In the second judgment, it does not matter whether the operation command input at the time t8 when the preparatory control is completed is the same as the operation command at the time t6 when the first judgment is made. Therefore, even if the operation command input at the time t8 when the preparatory control is completed is a different operation command (a second or subsequent operation command) from the operation command at the time t6, the target hydraulic valve is switched and the inverter 24 is activated.

As described above, according to this modified example, when the control unit 90 determines that the preparatory control is completed by the second judgment and an operation command is input from the operation switch 43, 35 at the time when the preparatory control is completed, the control unit 90 performs switching control of the target hydraulic valve. This allows the target hydraulic valve to be immediately driven when the preparatory control is completed, so that loading and unloading of garbage can be performed quickly.

[others]
It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not by the above meaning, and is intended to include the meaning equivalent to the claims and all modifications within the scope.

For example, during preparatory control, the control unit 90 need not perform switching control of the hydraulic valve based on an operation command for driving at least the hydraulic actuator. In other words, during preparatory control, the control unit 90 may perform switching control of the hydraulic valve based on an operation command that does not involve driving the hydraulic actuator (for example, an operation command to stop the driving of the push-in cylinder 112 and the hydraulic motor 117 by the stop switch 44).

In this embodiment, the control unit 90 makes the first and second judgments based on whether a predetermined time has elapsed since the start of the preparatory control, but may also make the judgments based on other methods, such as whether a signal indicating that startup preparation is complete is received from the inverter 24 during the third preparatory control.

The loading device T of this embodiment is a rotating plate type that loads garbage by cooperation between a push plate 108 and a rotating plate 115, but it may be a press type that loads garbage using only a push plate. Also, the garbage collection vehicle 1 of this embodiment discharges garbage to the outside by dumping the garbage storage box 2, but it may also discharge garbage to the outside using a discharge plate that is provided so as to be movable back and forth within the garbage storage box.

Furthermore, the refuse collection vehicle 1 may be provided with a dedicated work power switch for supplying power from the battery 4 to the work drive unit D2 in addition to the power switch 45. In this case, the power switch 45, the work power switch, and the main switch 34 are operated in sequence, and then the operation switches 43 and 35 are operated. When the switches are operated in this order, the timing for starting the preparation control may be any of the following timings A to C.
Timing A: The time when the power switch 45 is turned on (same as in this embodiment)
Timing B: The point at which the work power switch is turned on Timing C: The point at which the main switch 34 is switched to "loading" or "discharging" Timing C can also be applied in cases where the work power switch is not provided.

As with timing A in this embodiment, when preparatory control is being performed that is started at timing B or timing C, the control unit 90 does not perform switching control of the target hydraulic valve even if an operation command to drive the hydraulic actuators 20, 31, 112, 117, 119 is input from the operation switches 43, 35.

Furthermore, the garbage collection vehicle 1 may be provided with a dedicated preparation switch for starting preparation control. In this case, the timing for turning on the preparation switch (starting preparation control) may be any of the following timings D to F.
Timing D: The period after the power switch 45 is turned on and before the work power switch is turned on Timing E: The period after the work power switch is turned on and before the main switch 34 is switched to "loading" or "discharge" Timing F: The period after the main switch 34 is switched to "loading" or "discharge" and before the operation switches 43, 35 are operated Timing F can also be applied to cases where there is no work power switch.

When preparatory control is being performed at any of the timings D to F, the control unit 90 does not perform switching control of the target hydraulic valve even if an operation command to drive the hydraulic actuators 20, 31, 112, 117, and 119 is input from the operation switches 43 and 35.

The operation switches that output operation commands to drive the hydraulic actuators are not limited to the loading switch 43 and the discharge switch 35, and the main switch 34 may be the operation switch. In that case, even if a "loading" or "discharge" operation command is output by switching the main switch 34 while preparatory control is being performed that was started at any of the above timings A, B, D, and E, the control unit 90 does not need to allow the target hydraulic valve to operate due to that operation command. As a result, switching control of the target hydraulic valve is not performed.

The refuse collection vehicle 1 of this embodiment is equipped with a battery 4 that serves as a power source for driving the vehicle and a power source for the hydraulic actuators 20, 31, 112, 117, and 119, but it may also be equipped with a dedicated battery for each of these power sources.

The refuse collection vehicle 1 may be a vehicle powered by an engine and equipped with a battery as a power source exclusively for the hydraulic actuators 20, 31, 112, 117, 119. The refuse collection vehicle 1 may be a vehicle powered by an engine and a battery (a so-called hybrid vehicle) and configured to use the battery as a power source for the hydraulic actuators 20, 31, 112, 117, 119.
Furthermore, the present invention can be applied to work vehicles equipped with other hydraulic actuators in addition to refuse collection vehicles.

1. Refuse collection vehicle (work vehicle)
20 Swing cylinder (hydraulic actuator)
22 Hydraulic pump 23 Electric motor 24 Inverter 31 Tailgate lock cylinder (hydraulic actuator)
35 Discharge switch (operation switch)
43 Loading switch (operation switch)
90 Control unit 112 Push cylinder (hydraulic actuator)
117 Hydraulic motor (hydraulic actuator)
119 Dump cylinder (hydraulic actuator)
124 First hydraulic valve (hydraulic valve)
125 Second hydraulic valve (hydraulic valve)
126 Third hydraulic valve (hydraulic valve)
127 4th hydraulic valve (hydraulic valve)
128 5th hydraulic valve (hydraulic valve)

Claims (6)

An electric motor;
an inverter that drives and controls the electric motor;
a hydraulic pump that discharges hydraulic oil by being driven by the electric motor;
a hydraulic actuator that is driven by hydraulic oil supplied by the hydraulic pump;
a hydraulic valve for switching between supply and discharge of hydraulic oil to the hydraulic actuator;
an operation switch that outputs an operation command for driving the hydraulic actuator;
A control unit that performs switching control of the hydraulic valve based on the operation command,
The control unit determines whether preparatory control, including preparation for starting the inverter, is being performed at the time the operation command is input, and does not perform the switching control if it determines that the preparatory control is being performed. The work vehicle according to claim 1, wherein the control unit determines that the preparatory control is being performed when a predetermined time has not elapsed since the preparatory control was started. The work vehicle according to claim 1 or 2, wherein the control unit, when it determines that the preparatory control is being performed, further determines whether the preparatory control is completed, and when it determines that the preparatory control is completed and the operation command is input at the time when the preparatory control is completed, does not perform the switching control. The work vehicle according to claim 1 or 2, wherein the control unit, when it determines that the preparatory control is being performed, further determines whether the preparatory control is completed, and when it determines that the preparatory control is completed and the operation command is input at the time when the preparatory control is completed, performs the switching control. The work vehicle according to any one of claims 1 to 4, wherein the control unit, when it determines that the preparatory control is being performed, further determines whether the preparatory control is completed, and when it determines that the preparatory control is completed, outputs a notification command to notify the outside. The work vehicle according to any one of claims 3 to 5, wherein the control unit determines that the preparatory control is completed when a predetermined time has elapsed since the preparatory control was started.

Images