Work vehicles

Abstract

A dump truck, wherein a control device: generates a display screen image 100 including a charging power display section 130 that displays the magnitude of charging power to be charged to a battery within regenerative power, and a consumed power display section 140 that displays the magnitude of consumed power consumed by a power-consuming device; and causes a display device to display the display screen image. With this configuration, a driver can recognize the extent of charging power or consumed power per unit time corresponding to the current depression amount of a brake pedal, and regenerative power can be efficiently recovered by prompting the driver to operate brakes appropriately.

Description

Technical Field

[0001] The present invention relates to a work vehicle that includes a driving electric motor and causes a display device to display the magnitude of regenerative power generated by the electric motor.

Background Art

[0002] Conventionally, in a vehicle equipped with a driving electric motor, a technique for causing a display device to display the magnitude of regenerative power generated by the electric motor is known. For example, Patent Document 1 describes an electric vehicle including a driving motor supplied with power from a battery and display means for simultaneously displaying a target regenerative braking force and an actual regenerative braking force generated by the driving motor. In this electric vehicle, by displaying both the target regenerative braking force and the actual regenerative braking force on the display means and allowing the driver to recognize the control status of the regenerative braking force, even when controlling to adjust the target regenerative braking force according to the road surface condition, it is designed not to give the driver a sense of discomfort.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in a large work vehicle equipped with a driving electric motor such as an electric drive dump truck for a large-scale mine, of the regenerative power generated by the electric motor, the excess power that cannot be charged to the battery is configured to be consumed by a power consumption device (resistor). That is, in such a work vehicle, it was necessary to assume that when the driver's braking operation is steep, regenerative power exceeding the charging power that can be charged to the battery per unit time is generated, and efficient recovery of the regenerative power cannot be achieved.

[0005] This invention has been made in view of these problems, and its objective is to provide a work vehicle that can efficiently recover regenerative power generated by the electric motor used for driving by prompting the driver to perform appropriate braking operations. [Means for solving the problem]

[0006] To achieve the above objective, the present invention provides a work vehicle comprising a battery, an electric motor for driving connected to the battery, a power consumption device capable of consuming regenerative power generated by the electric motor, a display device for displaying various information, and a control device for controlling the electric motor, the power consumption device, and the display device. The battery is set to have a predetermined upper limit on the amount it can be charged per unit time, and the control device controls the regenerative power to charge the battery within a range below the upper limit, and to consume any surplus power exceeding the upper limit with the power consumption device. The control device generates a display screen in which a charging power display unit that displays the amount of charging power per unit time that is charged to the battery from the regenerative power, and a power consumption display unit that displays the amount of power consumed per unit time by the power consumption device that exceeds the upper limit on the amount the battery can be charged per unit time are arranged in succession, and displays this screen on the display device. [Effects of the Invention]

[0007] According to the work vehicle of the present invention, it is possible to prompt the driver to perform appropriate braking operations and efficiently recover regenerative power generated by the electric motor used for driving. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic side view showing a dump truck used as a work vehicle in the embodiment. [Figure 2] This is a schematic diagram showing an example of a dump truck system configuration. [Figure 3] This is an explanatory diagram showing an example of a display screen that can be shown on a display device. [Figure 4]This is an explanatory diagram showing the charging power display unit and power consumption display unit when the charging power per unit time increases. [Figure 5] This is an explanatory diagram showing the charging power display unit and power consumption display unit when the power consumption per unit time increases. [Figure 6] This is an explanatory diagram showing the charging power display and power consumption display when the upper limit of the battery's charging power falls below the specified value. [Modes for carrying out the invention]

[0009] One embodiment of the present invention will be described below with reference to the drawings. Figure 1 is a schematic side view showing a dump truck as a work vehicle of the embodiment. Figure 2 is a schematic configuration diagram showing an example of the system configuration of the dump truck. The dump truck 1 shown in Figure 1 is used as a work vehicle to load and transport materials such as soil and sand at work sites such as large-scale mines, and is driven by a motor 12 (electric motor) powered by electricity from a battery 10, which is transmitted to the rear wheels 4 for propulsion. In other words, the dump truck 1 is an electric dump truck that runs and works using electricity from the battery 10 as its power source.

[0010] As shown in Figure 1, the dump truck 1 comprises a body 2, a pair of left and right front wheels 3 and a pair of left and right rear wheels 4 (drive wheels) mounted on the body 2, a driver's cab 5 located on the upper front part of the body 2, and a cargo bed 6 mounted on the upper rear part of the body 2 so as to be rotatable in the vertical direction. Furthermore, as shown in Figure 2, the dump truck 1 also comprises a battery 10, a drive motor 12, an inverter 14, a power consumption device 20, a control device 30, and a display device 40.

[0011] Battery 10 is a secondary battery such as a lithium-ion battery, and has a battery module (not shown) which is composed of multiple battery cells. Battery 10 has a predetermined upper limit set for the amount of charge that can be charged per unit time. The upper limit is predetermined according to the specifications of battery 10 and is stored in a memory unit (not shown) of the control device 30. Furthermore, the upper limit may decrease from the predetermined value depending on various conditions such as the charge level (State of Charge) of battery 10, temperature, other control reasons, or the occurrence of an abnormality. The amount by which the upper limit decreases from the predetermined value is either stored in advance by the control device 30 according to the above conditions, or calculated by the control device 30 according to the above conditions.

[0012] The motor 12 is electrically connected to the battery 10 via the inverter 14 and is powered by the battery 10 to rotate the rear wheels 4 via a transaxle and drive shaft (not shown). In addition, when the driver depresses the brake pedal 52 or during deceleration with the accelerator off, the motor 12 is driven by the rotational force of the rear wheels 4 to generate regenerative power and apply regenerative braking force to the rear wheels 4.

[0013] The power consumption device 20 includes a chopper 22 and a resistor 24 (grid box). The chopper 22 is connected between the battery 10 and the inverter 14. The resistor 24 has a grid resistor (not shown) that is electrically connected between the battery 10 and the inverter 14 via the chopper 22. The power consumption device 20 consumes, for example, the excess power generated by the motor 12 during regenerative braking that exceeds the upper limit of the battery 10 by converting it into thermal energy using the resistor 24.

[0014] The control device 30 is a control device that performs overall control of the dump truck 1 and is composed of input / output devices, memory devices (ROM, RAM, non-volatile RAM, etc.), a central processing unit (CPU), etc. The control device 30 receives values ​​detected by various sensors, such as the amount the driver depresses the accelerator pedal 51 and brake pedal 52, and calculates the information necessary for controlling the dump truck 1. Based on the calculated information, the control device 30 outputs control signals to various devices such as the inverter 14 and chopper 22 to drive and control the motor 12 and power consumption device 20. The control device 30 also generates a display screen 100 (see Figure 3) to be displayed on the display device 40. The display device 40 is a device that has a display for displaying various information and is positioned, for example, in the driver's cab 5 so that the driver can see the display screen 100.

[0015] As described above, the dump truck 1, when decelerating, generates regenerative power with the motor 12 and applies regenerative braking force to the rear wheels 4. The control device 30 calculates the regenerative braking torque to be output from the motor 12 based on the braking force required when the dump truck 1 is decelerating, and controls the inverter 14 so that the calculated regenerative braking torque is output from the motor 12. The control device 30 also charges the battery 10 with regenerative power within the above-mentioned upper limit range, and controls the chopper 22 to consume any excess power generated by the power consumption device 20 (resistor 24). In addition, even if no excess power is generated, the control device 30 may consume a portion of the regenerative power with the power consumption device 20 (resistor 24) depending on the state of the battery 10.

[0016] Here, in the electric dump truck 1 used for operations in large-scale mines, generally, it often transports loads heavier than its own weight, and its energy consumption is greater than that of ordinary passenger cars. However, since the space for mounting the battery 10 as a power source in the dump truck 1 is limited, it is difficult to mount a battery 10 with a large capacity. Therefore, in order to obtain an efficient energy balance during driving, it is preferable to charge the battery 10 with the regenerative power generated by the motor 12 during regenerative braking as much as possible. However, when the driver's braking operation is steep, a large amount of regenerative power is generated by the motor 12 in a short time, and the surplus power consumed by the power consumption device 20 tends to increase. As a result, it may be impossible to achieve efficient recovery of regenerative power.

[0017] Therefore, in order to prompt the driver to perform an appropriate braking operation, the control device 30 generates the display screen 100 described below and causes the display device 40 to display it. FIG. 3 is an explanatory diagram showing an example of the display screen 100 displayed on the display device 40. The display screen 100 includes a charge rate display section 110, a discharge power display section 120, a charge power display section 130, and a power consumption display section 140.

[0018] When generating the display screen 100 shown in FIG. 3, the control device 30 acquires the values of the voltage and charge / discharge current of the battery 10 detected by a sensor (not shown), and calculates the current charge rate of the battery 10 and the charge / discharge power per unit time based on this. Further, the control device 30 acquires the values of the voltage and current in the resistor 24 detected by a sensor (not shown), and calculates and acquires the power consumption per unit time in the power consumption device 20 based on this. Note that the control device 30 may acquire the above charge power and the above power consumption based on the control value when controlling the chopper 22 so that the regenerative power is charged to the battery 10 within the range of the upper limit value and the surplus power is consumed by the power consumption device 20.

[0019] The details of the display screen 100 will be described while referring to FIG. 3. The charge rate display unit 110 is a display unit that displays the current charge rate of the battery 10. The charge rate display unit 110 includes a frame portion 111 that schematically shows the battery 10, and a plurality of segments 112 and an ECO charge mark 114 provided inside the frame portion 111. The plurality of segments 112 are scales indicating the current charge rate of the battery 10, and are arranged side by side along the vertical direction on the screen. The control device 30 turns off the segments 112 (the white portions in the figure) from the lower side to the upper side of the screen and turns them on (the gray portions in the figure) as the current charge rate of the battery 10 increases. Note that the current charge rate may be displayed by changing the color of the segments 112. Note that the control device 30 displays the current charge rate at the lower part of the frame portion 111 as "53%" in the figure.

[0020] The ECO charge mark 114 is a reference line composed of two straight lines that extend along the arrangement direction of the plurality of segments 112 in proximity to the plurality of segments 112. The ECO charge mark 114 includes, as two straight lines, a first mark 115 and a second mark 116 that is below the first mark 115 and shorter than the first mark 115. The first mark 115 and the second mark 116 are of different colors (for example, the first mark 115 is green and the second mark 116 is red). Thereby, when the lit portion among the plurality of segments 112 is within the range of the first mark 115, the driver can recognize that there is sufficient margin in the charge rate of the battery 10, and when the lit portion is within the range of the second mark 116, the driver can recognize that there is little margin in the charge rate of the battery 10.

[0021] The discharge power display unit 120, the charging power display unit 130, and the power consumption display unit 140 are arranged to the side of the charge rate display unit 110. The discharge power display unit 120, the charging power display unit 130, and the power consumption display unit 140 are arranged symmetrically vertically. The space between the discharge power display unit 120, the charging power display unit 130, and the power consumption display unit 140 displays the current vehicle speed of the dump truck 1, such as "15 km / h". An arrow 151 is provided between the discharge power display unit 120 and the charge rate display unit 110, which lights up when power is being discharged from the battery 10. An arrow 152 is provided between the charging power display unit 130, the power consumption display unit 140, and the charge rate display unit 110, which lights up when power is being charged to the battery 10.

[0022] The discharge power display unit 120 is a display unit that shows the magnitude of the charge / discharge power (in this case, discharge power) of the battery 10 per unit time during powered operation, when power is supplied from the battery 10 to the motor 12 for driving. The discharge power display unit 120 includes a plurality of segments 122 as a scale that shows the magnitude of the discharge power. Near the plurality of segments 122, a mark 124 extending along the direction of the arrangement of the plurality of segments 122 and the character (for example, "POWER" in the figure) indicating that powered operation is in progress are displayed. The control device 30 changes each segment 122 from off to on in the screen from left to right as the discharge power per unit time increases. Alternatively, the discharge power per unit time may be displayed by changing the color of the segments 122. Figure 3 shows an example in which all segments 122 are off (white) as a state of no discharge power.

[0023] The charging power display unit 130 is a display unit that shows the magnitude of the charge / discharge power (here, charging power) per unit time of the battery 10 during regenerative braking, in which the motor 12 generates regenerative power. The charging power display unit 130 includes a plurality of segments 132 as a scale that shows the magnitude of the charging power. The plurality of segments 132 are arranged in a line so as to form a substantially arc-shaped portion that is convex downwards. Near the plurality of segments 132, a mark 134 extending along the direction of arrangement of the plurality of segments 132 and characters (for example, "CHARGE" in the figure) indicating that the battery 10 is being charged with regenerative power are displayed. The control device 30 changes the segments 132 from an off state (areas marked in white in the figure) to an on state (areas marked in gray in the figure) from left to right on the screen as the charging power per unit time increases. Alternatively, the magnitude of the charging power may be indicated by changing the color of the segments 132.

[0024] The power consumption display unit 140 is a display unit that shows the amount of power consumed per unit time by the power consumption device 20 during regenerative braking, in which the motor 12 generates regenerative power. The power consumption display unit 140 includes a plurality of segments 142 as a scale to show the amount of power consumed. Near the plurality of segments 142, marks 144 extending along the direction of arrangement of the plurality of segments 142 and characters (such as "DISSIPATION" in the figure) indicating that the power consumption device 20 is consuming regenerative power are displayed. The starting end 140a of the power consumption display unit 140 (one end of segment 142 indicating that the power consumption value is 0) and the ending end 130a of the charging power display unit 130 (one end of segment 132 corresponding to the specified upper limit value of the battery 10) are arranged adjacent to each other. As a result, the charging power display unit 130 and the power consumption display unit 140 are arranged consecutively. The control device 30 changes the segment 142 on the screen from off (the white area in Figure 3) to on (the gray area in Figures 5 and 6) as the power consumption per unit time increases. Alternatively, the power consumption can be indicated by changing the color of the segment 142.

[0025] The display screen 100 during regenerative braking will be explained in detail with reference to the drawings. Figure 4 is an explanatory diagram showing the charging power display unit 130 and the power consumption display unit 140 when the charging power per unit time increases compared to the example shown in Figure 3. Figure 5 is an explanatory diagram showing the charging power display unit 130 and the power consumption display unit 140 when the power consumption per unit time increases.

[0026] When the driver presses the brake pedal 52 more firmly, as shown in the change from Figure 3 to Figure 4, the regenerative power generated by the motor 12 increases, increasing the charging power, and the rightmost segment 132 of the charging power display unit 130 changes to a lit state. If the driver presses the brake pedal 52 even more firmly, the regenerative power exceeds the upper limit of the battery 10, and the excess regenerative power is consumed by the power consumption device 20. As a result, as shown in the change from Figure 4 to Figure 5, the segment 142 included in the power consumption display unit 140 changes to a lit state, exceeding the end 130a of the charging power display unit 130. This allows the driver to recognize the amount of charging power or power consumption per unit time corresponding to the current amount the brake pedal 52 is pressed. In this embodiment, since the end 130a of the charging power display unit 130 and the start 140a of the power consumption display unit 140 are arranged adjacent to each other in a continuous sequence, it becomes possible to grasp the relationship between charging and consumption as a continuous series of states. For example, the driver can easily recognize when surplus regenerative power has begun to be consumed as power.

[0027] Furthermore, as mentioned above, the upper limit of the battery 10 may change from a specified value depending on various conditions such as the charge level and temperature. Therefore, when the upper limit of the battery 10 falls below the specified value, the control device 30 changes (reduces) the display range of the charging power displayed on the charging power display unit 130 according to the amount of decrease. Figure 6 is an explanatory diagram showing the charging power display unit 130 and the power consumption display unit 140 when the upper limit of the charging power of the battery 10 falls below the specified value. As shown in the figure, when the upper limit of the charging power of the battery 10 falls below the specified value, the control device 30 does not light up the segment 132 (the segment 132 located on the far right of the screen in Figure 6) corresponding to the decrease. Note that the color of the segment 132 corresponding to the decrease may be displayed in a different color from the other segments 132. Then, if power consumption exists, the control device 30 lights up the segments 142 of the power consumption display unit 140 from left to right. This makes it easy for the driver to recognize that the upper limit of the battery 10 has fallen below the specified value.

[0028] At the same time, the control device 30 displays an icon 160 on the display screen 100 indicating that the upper limit of the battery 10's charging power has fallen below a specified value. The icon 160 may change from an off state to an on state, or it may blink, when the upper limit falls below a specified value. This makes it easier for the driver to recognize that the upper limit of the battery 10 has fallen below a specified value.

[0029] Furthermore, while the regenerative power is charging the battery 10, the control device 30 changes the display mode of the display screen 100 from the non-charging state, as described below. For example, the control device 30 displays arrow 152 in Figure 3 by methods such as blinking the arrow 152, changing the color of the line, or switching the line type to a broken line and rotating the line. Note that when the battery 10 is discharging, the control device 30 displays arrow 151 using a similar method.

[0030] Furthermore, while the regenerative power is charging the battery 10, the control device 30 changes the display mode of the charge rate display unit 110 in Figure 3. For example, the control device 30 displays the illuminated segments 112 of the charge rate display unit 110 in a different color than when it is not charging. At this time, the color of the illuminated segments 112 may be changed sequentially from the bottom to the top to emphasize that the charge rate of the battery 10 is increasing. Alternatively, the control device 30 may display the frame 111 of the charge rate display unit 110, each segment 112, and the ECO charging mark 114 by flashing them, changing the color of the lines, or switching the line type to a broken line and rotating the lines. As described above, by changing the display mode of the arrow 152 and the charge rate display unit 110 from the non-charging state while the regenerative power is charging the battery 10, it becomes possible to easily make the driver aware that the current braking operation is charging the battery 10 with regenerative power.

[0031] As described above, in the dump truck 1 of the embodiment, the control device 30 generates a display screen 100 that includes a charging power display unit 130 that displays the amount of charging power that is charged to the battery 10 from the regenerative power, and a power consumption display unit 140 that displays the amount of power consumed by the power consumption device 20, and displays it on the display device 40.

[0032] This configuration allows the driver to recognize the amount of charging power or power consumption per unit time corresponding to the current amount of pressure applied to the brake pedal 52, enabling the driver to appropriately adjust the amount of pressure applied to the brake pedal 52 according to the road surface conditions on which the dump truck 1 is traveling. More specifically, it makes it possible to encourage the driver to consciously start pressing the brake pedal 52 earlier, so as not to generate a large amount of regenerative power in a short time by pressing the brake pedal 52 abruptly. In particular, since dump trucks 1 often travel on fixed routes such as mines, it is easy to consciously start pressing the brake pedal 52 earlier when decelerating, which is effective for the efficient recovery of regenerative power. Furthermore, it makes it possible to encourage the driver to suppress intermittent operation of pressing and releasing the brake pedal 52 when the dump truck 1 is going downhill. In other words, it makes it possible to encourage the driver to press the brake pedal 52 slowly and for a longer period of time when going downhill, so as to generate regenerative power gradually within the range in which the battery 10 can be charged.

[0033] Therefore, according to the embodiment of the dump truck 1, it is possible to efficiently recover regenerative power generated by the drive motor 12 by prompting the driver to perform appropriate braking operations. In addition, by encouraging the driver to press the brake pedal 52 gently, it is possible to reduce the load applied to the front wheels 3, rear wheels 4, and various structures of the dump truck 1.

[0034] This concludes the description of the embodiments, but the embodiments of the present invention are not limited to these embodiments. For example, in this embodiment, the present invention is applied to a dump truck 1 as a work vehicle equipped with a battery 10 and a motor 12, but the present invention may be applied to other work vehicles. Furthermore, the work vehicle to which the present invention is applied may further be equipped with an internal combustion engine and a generator driven by the power of the internal combustion engine, and the power generated by the generator is supplied to the motor 12. Furthermore, the work vehicle to which the present invention is applied may run by outputting power from the internal combustion engine to the drive wheels in addition to the power from the motor 12.

[0035] Furthermore, the dump truck 1 may be a trolley-type dump truck capable of running in trolley mode, powered by electricity supplied from the overhead line via a pantograph. In that case, if the power consumption device includes a configuration that allows a portion of the regenerative power to be supplied to the overhead line for consumption, the control device 30 may further display the power consumption per unit time supplied to the overhead line on the display screen 100.

[0036] Furthermore, the charging power display unit 130 may display charging power for any time period, not limited to the charging power per unit time mentioned above, and the power consumption display unit 140 may display power consumption for the same time period as the charging power display unit 130, not limited to the power consumption per unit time mentioned above.

[0037] Furthermore, the shape and arrangement of each segment in each display unit are not limited to those shown in Figures 3 to 6. For example, in Figures 3 to 6, segments 112, 122, 132, and 142 are spaced apart from each other, but the segments may be connected to each other. In that case, lines indicating the division between each segment may be displayed.

[0038] Furthermore, the end 130a of the charging power display unit 130 and the start 140a of the power consumption display unit 140 may be connected. Also, the arrangement of the charging power display unit 130 and the power consumption display unit 140 may differ from those shown in Figures 3 to 6, for example, by being arranged parallel to each other.

[0039] Furthermore, while Figures 3 to 6 show examples where the entire range within a single segment is illuminated or extinguished (or its color is changed), depending on the value to be displayed in each display unit, only a portion of the range within a single segment may be illuminated or extinguished (or its color changed). [Explanation of Symbols]

[0040] 1 Dump truck 10 batteries 12. Motor (Electric Motor) 20 Power consumption equipment 24 resistor 30 Control device 40 Display device 100 display screens 110 Charging rate display section 120 Discharge power display section 130 Charging power display section 130a termination 140a Starting point 140 Power consumption display section 160 icons

Claims

1. Battery and An electric motor connected to the aforementioned battery, A power consumption device capable of consuming the regenerative power generated by the aforementioned electric motor, A display device that shows various information, The electric motor, the power consumption device, and the control device for controlling the display device In a work vehicle equipped with, The aforementioned battery has a predetermined upper limit set for the amount of charge that can be applied per unit time. The control device controls the regenerative power to charge the battery within a range below the upper limit, and to consume any excess power exceeding the upper limit with the power consumption device, A work vehicle that generates a display screen in which a charging power display unit that displays the amount of charging power per unit time that is charged to the battery from the regenerative power, and a power consumption display unit that displays the amount of power consumed per unit time by the power consumption device that exceeds the upper limit that the battery can charge per unit time are arranged in succession, and displays the screen on the display device.

2. The work vehicle according to claim 1, wherein the end of the charging power display unit and the start of the power consumption display unit are adjacent to each other and arranged in a continuous manner.

3. The work vehicle according to claim 1, wherein the control device changes the display range of the charging power displayed on the charging power display unit according to the amount of decrease when the upper limit of the power that can be charged to the battery falls below a specified value.

4. The work vehicle according to any one of claims 1 to 3, wherein the control device displays an icon on the display screen indicating that the upper limit of the power that can be charged to the battery has fallen below a specified value.

5. The work vehicle according to claim 1, wherein the control device generates a display screen that further includes a charge rate display unit that displays the current charge rate of the battery, and changes the display mode of the charge rate display unit from non-charging mode while the regenerative power is charging the battery.

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