Work vehicle

Abstract

To provide a work vehicle that can further improve power consumption by preventing the battery from discharging when it is not necessary to discharge it.SOLUTION: In a work vehicle 1, its main controller 8 turns off a relay 33 via a sub-controller 9 to stop power supply from the battery 49 to a first drive part 15 when a set time T1 has elapsed without any input operation from the time when a lock lever 5c is raised and the operation of a working device 7 by an operating lever 5a is disabled.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a work vehicle.

Background Art

[0002] Conventionally, a hydraulic excavator has been proposed that stops the prime mover when the operation of the working device has not been performed for a predetermined time (Patent Document 1: Japanese Patent Application Laid-Open No. 2022-104124). Also, an electric excavator has been proposed that stops the drive source when a lock operation that invalidates the operation of the operation lever is received (Patent Document 2: Japanese Patent Application Laid-Open No. 2023-070976).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] An electric motor is quieter than an engine, and it may be difficult to determine whether it is in a power supply state or a power supply stop state. Therefore, the battery may continue to supply power. If the battery continues to supply power when the operator is absent, there is a problem that the amount of wasted energy consumption increases due to over-discharge of the battery.

Means for Solving the Problems

[0005] In view of the above circumstances, the present invention aims to provide a work vehicle capable of further improving electricity costs by preventing over-discharge of the battery.

[0006] As one embodiment, the above problems are solved by the solutions disclosed below.

[0007] The work vehicle according to the present invention includes a plurality of work devices operated by hydraulic pressure, a drive unit that drives the work devices, a battery, a main controller, a sub-controller, a plurality of operation levers, and a lock lever.

[0008] When the set time has elapsed in a state where there is no input operation since the lock lever has been raised and the operation of the work device by the operation lever has been invalidated, the main controller turns off the relay via the sub-controller and stops power supply from the battery to the drive unit.

[0009] According to this configuration, when the set time has elapsed in a state where there is no input operation to the display unit, the operation switch unit, etc., the machine body shuts down. Therefore, it is possible to prevent the battery from continuously supplying power in a state where the operator is absent.

[0010] As an example, when the lock lever is lowered and the start switch is pressed, the main controller turns on the relay via the sub-controller, starts power supply from the battery to the drive unit, starts operating the drive unit in a state where the password is authenticated, and enables the operation of the work device by the operation lever.

[0011] As an example, when there is the input operation during the period until the set time is reached, the main controller maintains the on state of the relay.

Effects of the Invention

[0012] According to the present invention, it is possible to realize a work vehicle capable of further improving the electricity cost by preventing over-discharge of the battery.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view showing an example of a work vehicle 1 according to the present embodiment, and is a perspective view from above the upper left rear part. Here, a hydraulic excavator will be described as an example. As a configuration other than the above, the work vehicle 1 may be a wheel loader, a carrier, or the like. In all the drawings for explaining the embodiments, members having the same function are denoted by the same reference numerals, and repeated explanations thereof may be omitted.

[0015] As shown in FIG. 1, the work vehicle 1 includes a lower body 2 that can travel and an upper body 3 that is disposed on the lower body 2 and can swing. The lower body 2 has a traveling device 6a, and the upper body 3 has a driver's cab 4. Here, the portion surrounded by the broken line P1 in the figure is a schematic structural diagram schematically showing the main part of the driver's cab 4.

[0016] As an example, the traveling device 6a includes a pair of left and right crawlers. The traveling device 6a has a traveling hydraulic motor 17a on the left traveling body and a traveling hydraulic motor 17b on the right traveling body. As a configuration other than the above, a traveling device equipped with tires may be used.

[0017] The work vehicle 1 has a battery 49 that supplies electric power. The battery 49 is built into the battery pack 47. The work vehicle 1 has a display unit 98. The display unit 98 is configured to be able to display the operation information of the first drive unit 15 and the second drive unit 16, the remaining capacity information of the battery pack 47, and other known vehicle information. Also, an in-vehicle charger is provided (not shown).

[0018] As an example, the cab 4 has a seat 4a on which the operator rides and sits, a lock lever 5c arranged on the left side of the seat 4a, and a display unit 98 arranged on the right side of the seat 4a. Also, the cab 4 has operation levers 5a arranged on the left side and the right side of the seat 4a, respectively.

[0019] As an example, a seat switch 5d is arranged below the seat 4a, and a start switch 4b is arranged on the right side of the seat 4a. The seat switch 5d is a mechanical switch or a pressure-sensitive switch that operates by the load when the operator sits on the seat 4a. The start switch 4b is a push-type switch that serves both for starting and stopping.

[0020] As an example, an operation switch unit 99 is arranged on the right side of the seat 4a. As an example, the operation switch unit 99 has any one or more of a jog dial, a tactile switch, a lever-type switch, a push-type switch, a pressure-sensitive switch, or a touch panel.

[0021] As an example, the operation switch unit 99 has any one or more of an eco-mode selection switch, a lift alarm operation switch, a beacon switch, a detent switch, a throttle switch, a light switch, a wiper switch, or a washer switch.

[0022] The work vehicle 1 has a plurality of working devices 7. All of the plurality of working devices 7 are operated by hydraulic pressure (operating oil at a predetermined pressure).

[0023] As an example, the working device 7 includes a dump plate 51a. The dump plate 51a swings vertically with respect to the lower body 2 by a dump plate cylinder 18a. The arm 51c swings vertically with respect to the boom 51b by an arm cylinder 18b.

[0024] As an example, the working device 7 has a boom 51b, an arm 51c, and an attachment 51d. The boom 51b is attached to the upper body 3 so as to be swingable in the vertical direction including the vertical direction and the front-rear component. The arm 51c is attached to the boom 51b so as to be swingable in the vertical direction including the vertical direction and the front-rear component. The attachment 51d is attached to the arm 51c so as to be swingable in the vertical direction including the vertical direction and the front-rear component.

[0025] As an example, the attachment 51d is a bucket, and swings vertically with respect to the arm 51c by a bucket cylinder 18c. As an example, the boom 51b swings vertically with respect to the upper body 3 by a boom cylinder and swings horizontally with respect to the upper body 3 by a swing cylinder (not shown).

[0026] FIG. 2 is a schematic circuit diagram showing an example of a drive control system in the work vehicle 1. The work vehicle 1 includes a traveling hydraulic motor 17a and a traveling hydraulic motor 17b, and a first drive unit 15 that supplies hydraulic oil at a predetermined pressure to the dump plate cylinder 18a, the arm cylinder 18b, and the bucket cylinder 18c. Note that the circuit diagram in FIG. 2 partially omits notations other than the main parts.

[0027] The work vehicle 1 includes a slewing device 6b that is operated by a second drive unit 16. As an example, the second drive unit 16 has a slewing electric motor 16a assembled with a speed reducer 16c, and a pinion gear of the speed reducer 16c meshes with a slewing bearing of the lower body 2 (not shown).

[0028] As shown in FIGS. 2 and 3, the work vehicle 1 has a battery pack 47. The battery pack 47 is detachably mounted on the work vehicle 1. As an example, the battery pack 47 has a battery management system 48, a battery 49, and a contactor 34.

[0029] As an example, the battery 49 is a lithium-ion battery combining a large number of cells, and the power supply voltage is 80 to 800 [V]. The battery pack 47 incorporates various sensors, and in the figure, their wiring diagrams are omitted. As an example, the work vehicle 1 has a lead battery 46 that supplies power to the battery management system 48 at startup.

[0030] The work vehicle 1 starts when the operator presses the start switch 4b. The work vehicle 1 has a main controller 8 (vehicle controller) and a sub-controller 9 (switch ASSY controller). When the start switch 4b is pressed, the main controller 8 sends a power supply start signal to the sub-controller 9, and the sub-controller 9 that receives the power supply start signal turns on the relay 33.

[0031] When the relay 33 is turned on, the battery management system 48 turns on the contactor 34. When the contactor 34 is turned on, power supply from the battery 49 to the first drive unit 15 and the second drive unit 16 is started. After the power supply is started, the operator operates the operation lever 5a to operate the traveling device 6a, the slewing device 6b, and the work device 7.

[0032] When the operator operates the operation lever 5a, an operation signal is sent to the main controller 8, and the first drive unit 15 and the second drive unit 16 are operated by the main controller 8 that has received the operation signal. The communication protocol in vehicle control including the main controller 8 and the sub-controller 9 applies Controller Area Network (CAN). As an example, the relay 33 is an ACC relay attached to the accessory power supply.

[0033] The first drive unit 15 has a first hydraulic pump 22a that sucks in and discharges the hydraulic oil stored in the hydraulic oil tank 54. Further, the first drive unit 15 has a first electric motor 21a that drives the first hydraulic pump 22a, and a first inverter 25a that supplies power to the first electric motor 21a according to a command from the main controller 8.

[0034] The first drive unit 15 has a second hydraulic pump 22b that sucks in and discharges the hydraulic oil stored in the hydraulic oil tank 54. Further, the first drive unit 15 has a second electric motor 21b that drives the second hydraulic pump 22b, and a second inverter 25b that supplies power to the second electric motor 21b according to a command from the main controller 8.

[0035] As an example, the first drive unit 15 is configured to combine the first output part of the first hydraulic pump 22a and the second output part of the second hydraulic pump 22b and send the hydraulic oil to the primary side of the control valve unit 10.

[0036] The control valve unit 10 has a plurality of control valves with their primary sides connected in parallel. In the example of FIG. 2, the primary sides of the control valves 11a and 11b for the hydraulic motor and the control valves 12a, 12b, and 12c for the hydraulic cylinder are connected in parallel. Here, the number of various control valves constituting the control valve unit 10 may increase or decrease respectively.

[0037] The control valve unit 10 has a relief valve 43, and the primary side of the relief valve 43 is connected in parallel to the primary sides of the respective control valves. The secondary side of the relief valve 43 forms a return flow path, and the hydraulic oil exceeding the set pressure is returned to the hydraulic oil tank 54.

[0038] As an example, the primary side of the first check valve 41a is connected to the output side of the first hydraulic pump 22a, and the primary side of the second check valve 41b is connected to the output side of the second hydraulic pump 22b. Then, the secondary sides of the first check valve 41a and the second check valve 41b merge and are connected to the primary side of the control valve unit 10. As an example, both the first hydraulic pump 22a and the second hydraulic pump 22b are fixed-displacement gear pumps. As an example, both the first electric motor 21a and the second electric motor 21b are embedded magnet motors.

[0039] The first drive unit 15 includes a rotation speed sensor 45a that detects the rotation speed of the first electric motor 21a and a rotation speed sensor 45b that detects the rotation speed of the second electric motor 21b. Further, the first drive unit 15 includes a temperature sensor 44 that detects the temperature of the hydraulic oil stored in the hydraulic oil tank 54.

[0040] The second drive unit 16 includes a swivel electric motor 16a assembled with a speed reducer 16c and a swivel inverter 16b that supplies power to the swivel electric motor 16a according to a command from the main controller 8. The second drive unit 16 includes a rotation speed sensor 45c that detects the rotation speed of the swivel electric motor 16a.

[0041] As an example, the cab 4 is equipped with an air conditioner 26. The air conditioner 26 includes an air conditioner electric motor 26a and an air conditioner inverter 26b that supplies power to the air conditioner electric motor 26a according to a command from the main controller 8.

[0042] Figure 4 is a schematic flowchart diagram that simply shows an example of the control procedure by the main controller 8 and the sub-controller 9 in the work vehicle 1. The control procedure shown in Figure 4 consists of steps S1 to S9. Subsequently, the control procedure in the work vehicle 1 will be described below.

[0043] In step S1 of FIG. 4, the main controller 8 transmits a power supply start signal to the sub-controller 9 when the start switch 4b is pressed. Then, the sub-controller 9 that has received the power supply start signal turns on the relay 33. When the relay 33 is turned on, power supply from the battery 49 to the first drive unit 15 and the second drive unit 16 is started. When the power supply is started, the process proceeds to step S2.

[0044] In step S2 of FIG. 4, the main controller 8 displays a password input screen on the display unit 98. When the password input screen is displayed, the process proceeds to step S3.

[0045] In step S3 of FIG. 4, the main controller 8 authenticates the password entered by the operator. When the main controller 8 authenticates the password, the process proceeds to step S4. On the other hand, when the main controller 8 does not authenticate the password, it returns to step S2 to redisplay the password input screen. Or, it returns to step S2 to redisplay the password input screen while displaying an error message.

[0046] In step S4 of FIG. 4, the main controller 8 determines whether the lock lever 5c is down. When the main controller 8 determines that the lock lever 5c is down, the process proceeds to step S5. On the other hand, when the main controller 8 determines that the lock lever 5c is not down, it returns to step S4.

[0047] In step S5 of FIG. 4, the main controller 8 starts the operation of the first drive unit 15 and the second drive unit 16, enables the operation of the plurality of operation levers 5a, and proceeds to step S6.

[0048] In step S6 of FIG. 4, the main controller 8 determines whether the lock lever 5c is raised. When the main controller 8 determines that the lock lever 5c is raised, the process proceeds to step S7. On the other hand, when the main controller 8 determines that the lock lever 5c is not raised, the process returns to step S6.

[0049] In step S7 of FIG. 4, the main controller 8 stops the operation of the first drive unit 15 and the second drive unit 16, invalidates the operation of the operation lever 5a, displays a countdown on the display unit 98, and proceeds to step S8. The countdown display will be described later.

[0050] In step S8 of FIG. 4, the main controller 8 determines whether the set time T1 has elapsed. When the main controller 8 determines that the set time T1 has elapsed, the process proceeds to step S9. On the other hand, when the main controller 8 determines that the set time T1 has not elapsed, the process returns to step S8.

[0051] In step S9 of FIG. 4, the main controller 8 sends a power supply stop signal to the sub-controller 9. Then, the sub-controller 9 that has received the power supply stop signal turns off the relay 33. When the relay 33 is turned off, the power supply from the battery 49 to the first drive unit 15 and the second drive unit 16 is stopped.

[0052] Subsequently, the schematic timing chart of the drive control in the work vehicle 1 will be described below.

[0053] FIG. 5 is a timing chart diagram of the first example. The first example shows that when the set time T1 elapses in a state where there is no input operation from the time when the operation of the work device 7 by the operation lever 5a is invalidated, the power supply to the first drive unit 15 and the second drive unit 16 is stopped.

[0054] FIG. 6 is a timing chart diagram of the second example. The second example is an example when an input operation occurs before the elapse of the set time T1 from the time when the operation of the working device 7 by the operation lever 5a is disabled. The second example shows that the power supply to the first drive unit 15 and the second drive unit 16 is stopped when the set time T1 elapses from the state where there is no last input operation.

[0055] In step S7 of FIG. 4, when an input operation occurs before the elapse of the set time T1, the main controller 8 resets the count toward the set time T1 and starts the count from the time when the input operation occurred.

[0056] According to this configuration, when the operator operates the touch panel or operation buttons of the display unit 98 or operates various switches of the operation switch unit 99, the on state of the relay 33 is maintained. Then, the automatic shutdown of the machine body is not executed, and the count toward the set time T1 restarts from zero. Therefore, flexible response according to the working situation of the operator can be achieved, and a more user-friendly configuration can be obtained.

[0057] As an example, the above countdown display is performed by lighting an icon, or blinking an icon, or changing the color of the icon, for example, changing from yellow to red, on a predetermined screen of the display unit 98.

[0058] As an example, when the countdown toward the set time T1 starts, the main controller 8 lights the icon. After that, when one minute has elapsed since the start of the countdown toward the set time T1, the main controller 8 blinks the icon. The set time T1 can be changed with a service tool.

[0059] As an example, in step S2 of FIG. 4, for each password of the logged-in user, whether or not to perform automatic shutdown can be stored in the database and the condition can be carried over at the next startup.

[0060] In addition to the above configuration, when the set time T1 has elapsed in a state where there is no input operation and the seat switch 5d is not activated, the power supply from the battery 49 to the first drive unit 15 and the second drive unit 16 may be stopped.

[0061] In addition to the above configuration, when the seat switch 5d is activated without the set time T1 elapsing, the countdown towards the set time T1 may be reset and the countdown may be restarted from the point in time when the seat switch 5d is activated.

[0062] According to the work vehicle 1 of the present embodiment described above, further improvement in the electricity cost of the first electric motor 21a and the second electric motor 21b can be achieved. In addition, restricting the power supply time of the first electric motor 21a and the second electric motor 21b in a state where there is no predetermined input operation also enhances safety.

[0063] Note that the drive source of the work vehicle 1 is not limited to the above configuration, and a configuration in which an engine is used in combination with the electric motor may be employed. Further, the battery of the work vehicle 1 is not limited to the above configuration, and known secondary batteries such as nickel-metal hydride batteries are applicable. Thus, the work vehicle 1 may be appropriately changed according to specifications and the like.

Explanation of Signs

[0064] 1 Work vehicle 2 Lower body 3 Upper body 4 Cab, 4a Seat, 4b Start switch 5a Operation lever, 5c Lock lever 6a Travel device, 6b Swing device 7 Working device 8 Main controller (vehicle controller) 9 Sub-controller (switch ASSY controller) 10 Control valve unit 11a, 11b Control valves for hydraulic motors 12a, 12b, 12c Control valves for hydraulic cylinders 15 First drive unit 16 Second drive unit, 16a Rotary electric motor, 16b Rotary inverter 17a, 17b Travel hydraulic motor 18a Earth discharge plate cylinder (hydraulic cylinder) 18b Arm cylinder (hydraulic cylinder) 18c Bucket cylinder (hydraulic cylinder) 21a First electric motor, 21b Second electric motor 22a First hydraulic pump, 22b Second hydraulic pump 25a First inverter, 25b Second inverter 26 Air conditioner, 26a Electric motor for air conditioner, 26b Inverter for air conditioner 33 Relay 34 Contactor 41a First check valve, 41b Second check valve 43 Relief valve 44 Temperature sensor 45a, 45b, 45c Rotation speed sensor 46 Lead battery 47 Battery pack 48 Battery management system (BMS) 49 Battery (lithium-ion battery) 51a Earth discharge plate, 51b Boom, 51c Arm, 51d Attachment (bucket) 54 Hydraulic oil tank 98 Display unit 99 Operation switch unit T1 Set time

Claims

1. A work vehicle comprising a plurality of working devices actuated by hydraulic pressure, a drive unit for driving the working devices, a battery, a main controller, a sub-controller, a plurality of operation levers, and a lock lever, wherein when the lock lever is raised and the operation of the working device by the operation lever is disabled, and a set time has elapsed in a state without an input operation from the time point when the operation is disabled, the main controller turns off a relay via the sub-controller to stop power supply from the battery to the drive unit. A work vehicle characterized by the above.

2. When the lock lever is lowered and the start switch is pressed, the main controller turns on the relay via the sub-controller to start power supply from the battery to the drive unit, and starts operating the drive unit in a state where a passcode is authenticated to enable the operation of the working device by the operation lever. The work vehicle according to Claim 1, characterized by the above.

3. When there is an input operation during the period until the set time is reached, the main controller maintains the on state of the relay. The work vehicle according to Claim 2, characterized by the above.

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