Work vehicle

Abstract

In a dump truck, a control device generates a display screen (100) including a charging power display unit (130) that displays the magnitude of charging power to be charged into a battery among regenerative power, and a power consumption display unit (140) that displays the magnitude of power consumption consumed by a power consumption device, and displays the display screen on a display device. According to this configuration, a driver can recognize the degree of charging power or power consumption per unit time corresponding to the current amount of depression of a brake pedal, and can be prompted to perform an appropriate braking operation to efficiently recover regenerative power.

Description

Technical Field

[0001] The present invention relates to a work vehicle having an electric motor for traveling and having a display device indicating the magnitude of regenerative electric power generated by the electric motor. Background Art

[0002] Conventionally, in vehicles equipped with electric motors for propulsion, technologies are known for displaying the amount of regenerative power generated by the electric motors on a display device. For example, Patent Document 1 describes an electric vehicle equipped with a propulsion motor supplied with power from a battery, and a display unit that simultaneously displays the target regenerative braking force and the actual regenerative braking force generated by the propulsion motor. In this electric vehicle, by displaying both the target regenerative braking force and the actual regenerative braking force on the display unit, the driver can identify the regenerative braking force control status. This allows the driver to avoid feeling uncomfortable even when the target regenerative braking force is adjusted according to road conditions.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 6856885 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] However, in large-scale mining dump trucks equipped with electric motors for propulsion, a configuration is employed in which the excess regenerative power generated by the electric motor, which cannot be used to charge the battery, is consumed by a power consumption device (a resistor). Specifically, in such work vehicles, it is necessary to anticipate the possibility that a sudden braking operation by the driver could generate regenerative power exceeding the amount of power that can be charged to the battery per unit time, making efficient recovery of regenerative power impossible.

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a work vehicle that encourages the driver to perform appropriate braking operations and can efficiently recover regenerative electric power generated by an electric motor for traveling.

[0009] Means for solving problems

[0010] In order to achieve the above-mentioned purpose, the working vehicle of the present invention comprises: a battery; an electric motor for traveling, which is connected to the battery; a power consumption device, which can consume the regenerative power generated by the electric motor; a display device, which displays various information; and a control device, which controls the electric motor, the power consumption device and the display device, wherein the control device generates a display screen including a charging power display unit and a consumption power display unit, which is displayed on the display device, the charging power display unit displays the amount of charging power in the regenerative power charged to the battery, and the consumption power display unit displays the amount of consumed power consumed by the power consumption device.

[0011] Effects of the Invention

[0012] According to the work vehicle of the present invention, it is possible to encourage the driver to perform appropriate braking operations and efficiently recover regenerative electric power generated by the electric motor for traveling. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a side view schematically showing a dump truck as a work vehicle according to the embodiment.

[0014] Figure 2 This is a schematic configuration diagram showing an example of a system configuration of a dump truck.

[0015] Figure 3 This is an explanatory diagram showing an example of a display screen displayed on a display device.

[0016] Figure 4 It is an explanatory diagram showing the charging power display unit and the power consumption display unit when the charging power per unit time increases.

[0017] Figure 5 It is an explanatory diagram showing the charging power display unit and the power consumption display unit when the power consumption per unit time increases.

[0018] Figure 6 It is an explanatory diagram showing the charging power display unit and the power consumption display unit when the upper limit value of the battery charging power drops from a prescribed value. DETAILED DESCRIPTION

[0019] Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings. Figure 1 1 is a side view schematically showing a dump truck as a working vehicle according to an embodiment. Figure 2 This is a schematic configuration diagram showing an example of a system configuration of a dump truck. Figure 1The illustrated dump truck 1 is used as a work vehicle for loading and transporting loads such as sand and soil at work sites such as large-scale mines. The dump truck 1 travels by transmitting power from a motor 12 (electric motor) driven by electricity from a battery 10 to rear wheels 4. Specifically, the dump truck 1 is an electric dump truck that uses electricity from the battery 10 as a power source for travel and operation.

[0020] like Figure 1 As shown, the dump truck 1 includes a vehicle body 2, a pair of left and right front wheels 3 provided on the vehicle body 2, a pair of left and right rear wheels 4 (drive wheels), a cab 5 provided on the upper front portion of the vehicle body 2, and a cargo box 6 mounted on the upper rear portion of the vehicle body 2 so as to be rotatable in the vertical direction. Figure 2 As shown, the dump truck 1 includes a battery 10 , a motor 12 for traveling, an inverter 14 , a power consumption device 20 , a control device 30 , and a display device 40 .

[0021] The battery 10 is a secondary battery such as a lithium-ion battery, and has a battery module (not shown) composed of a plurality of battery cells. The battery 10 is set with a predetermined upper limit value of the charging power that can be charged per unit time. The upper limit value is predetermined according to the specifications of the battery 10 and is stored in a storage unit (not shown) of the control device 30. In addition, the upper limit value is sometimes reduced from the prescribed value according to various conditions such as the charging rate (State Of Charge) of the battery 10, temperature, other control reasons, and the occurrence of abnormalities. The amount of reduction in the upper limit value relative to the prescribed value is pre-stored by the control device 30 according to the above conditions, or calculated by the control device 30 according to the above conditions.

[0022] The motor 12 is electrically connected to the battery 10 via an inverter 14 and is driven by power supplied from the battery 10 to rotate the rear wheels 4 via a transaxle and drive shaft (not shown). Furthermore, during deceleration with the accelerator off, such as when the driver steps on the brake pedal 52, the motor 12 is driven by the rotational force of the rear wheels 4 to generate regenerative electricity, thereby applying regenerative braking force to the rear wheels 4.

[0023] 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 resistance (not shown) electrically connected between the battery 10 and the inverter 14 via the chopper 22. The power consumption device 20 converts the excess regenerative power generated by the motor 12 during regenerative braking, for example, exceeding the upper limit of the battery 10, into heat energy and consumes it through the resistor 24.

[0024] The control device 30 is a control device that performs comprehensive control of the dump truck 1, and is composed of an input / output device, a storage device (ROM, RAM, non-volatile RAM, etc.), a central processing unit (CPU), etc. The control device 30 inputs values ​​detected by various sensors such as the amount of depression of the driver's accelerator pedal 51 and brake pedal 52, and calculates information required 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 the chopper 22, and drives and controls the motor 12 and the power consumption device 20. In addition, the control device 30 generates a display screen 100 (see Figure 3 The display device 40 is a device including a display for displaying various information, and is disposed in the cab 5 at a position where the driver can visually recognize a display screen 100 , for example.

[0025] As described above, the dump truck 1 configured as described above generates regenerative power by the motor 12 and applies regenerative braking force to the rear wheels 4 during deceleration of the dump truck 1 .

[0026] The control device 30 calculates the regenerative braking torque to be output from the motor 12 based on the braking force required during deceleration of the dump truck 1, and controls the inverter 14 so that the calculated regenerative braking torque is output from the motor 12. Furthermore, the control device 30 controls the chopper 22 so that the regenerative power is charged to the battery 10 within the aforementioned upper limit and, if surplus power is generated, consumed by the power consumption device 20 (resistor 24). Furthermore, even if the aforementioned surplus power is not generated, the control device 30 may cause the power consumption device 20 (resistor 24) to consume a portion of the regenerative power, depending on the state of the battery 10.

[0027] Here, in the electrically driven dump truck 1 used for operations in large-scale mines, most of the time, cargo heavier than the dump truck's own weight is carried, and the energy consumption is greater than that of an ordinary passenger car. However, the space for mounting the battery 10 as the power source on the dump truck 1 is limited, making it 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 abrupt, the motor 12 generates a large amount of regenerative power in a short period of time, and the remaining amount of power consumed by the power consumption device 20 tends to increase. As a result, efficient recovery of the regenerative power may not be achieved.

[0028] Therefore, in order to prompt the driver to perform an appropriate braking operation, the control device 30 generates a display screen 100 described below and displays it on the display device 40 . Figure 31 is an explanatory diagram showing an example of a 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 .

[0029] The control device 30 generates Figure 3 When displaying the display screen 100 shown, the control device 30 obtains the voltage and charge / discharge current values ​​of the battery 10 detected by sensors (not shown), and calculates the current charge rate of the battery 10 and the charge / discharge power per unit time based on these values. Furthermore, the control device 30 obtains the voltage and current values ​​of the resistor 24 detected by sensors (not shown), and calculates and obtains the power consumption per unit time of the power consuming device 20 based on these values. Alternatively, the control device 30 can obtain the charging power and the power consumption based on control values ​​when controlling the chopper 22 so that the regenerative power is charged to the battery 10 within the upper limit and the power consuming device 20 consumes the remaining power.

[0030] Reference Figure 3 The display screen 100 will be described in detail. The charging rate display unit 110 is a display unit that displays the current charging rate of the battery 10. The charging rate display unit 110 includes a frame 111 that schematically represents the battery 10, and a plurality of segments 112 and an ECO charging mark 114 provided inside the frame 111. The plurality of segments 112 are scales that represent the current charging rate of the battery 10 and are arranged in the vertical direction of the screen. As the current charging rate of the battery 10 increases, the control device 30 changes the segments 112 from an off state (the portion marked in white in the figure) to a lit state (the portion marked in gray in the figure) from the bottom to the top of the screen. In addition, the current charging rate can also be displayed by changing the color of the segment 112. In addition, the control device 30 displays the current charging rate at the bottom of the frame 111 as "53%" in the figure.

[0031] The ECO charge mark 114 is a reference line formed by two straight lines that are close to the plurality of segments 112 and extend along the arrangement direction of the plurality of segments 112. The two straight lines comprise a first mark 115 and a second mark 116 that is located below and shorter than the first mark 115. The first mark 115 and the second mark 116 are different colors (for example, the first mark 115 is green and the second mark 116 is red). This allows the driver to recognize that the remaining charge level of the battery 10 is sufficient when the illuminated portion of the plurality of segments 112 is within the range of the first mark 115, and that the remaining charge level of the battery 10 is low when the illuminated portion is within the range of the second mark 116.

[0032] The discharge power display 120, charge power display 130, and power consumption display 140 are positioned to the sides of the charge rate display 110. The discharge power display 120, charge power display 130, and power consumption display 140 are arranged vertically symmetrically. The space between the discharge power display 120, charge power display 130, and power consumption display 140 displays the current speed of the dump truck 1, such as "15 km / h." An arrow 151 is provided between the discharge power display 120 and the charge rate display 110. This arrow 151 illuminates when the battery 10 is being discharged. Furthermore, an arrow 152 is provided between the charge power display 130, charge power display 140, and the charge rate display 110. This arrow 152 illuminates when the battery 10 is being charged.

[0033] The discharge power display unit 120 is a display unit that indicates the size of the charge and discharge power (here, discharge power) of the battery 10 per unit time during power operation in which power is supplied from the battery 10 to the motor 12. The discharge power display unit 120 includes a plurality of segments 122 as scales indicating the size of the above-mentioned discharge power. In addition, near the plurality of segments 122, marks 124 extending along the arrangement direction of the plurality of segments 122 and characters indicating that it is power operation (for example, "power" in the figure) are displayed. The greater the discharge power per unit time, the more the control device 30 changes each segment 122 from an off state to a lit state from the left side to the right side of the screen. In addition, the discharge power per unit time can also be displayed by changing the color of the segment 122. In Figure 3 , an example is shown in which all the segments 122 are turned off (white) as a state in which there is no discharge power.

[0034] The charging power display unit 130 is a display unit that indicates the amount of charge and discharge power (herein, charging power) of the battery 10 per unit time during regenerative braking, in which regenerative power is generated by the motor 12. The charging power display unit 130 includes a plurality of segments 132 as a scale indicating the amount of charging power. The plurality of segments 132 are arranged so as to form a generally arc-shaped portion that is convex downward. Markers 134 extending along the arrangement direction of the plurality of segments 132 and characters indicating that regenerative power is being charged to the battery 10 (e.g., "Charging" in the figure) are displayed near the plurality of segments 132. As the charging power per unit time increases, the control device 30 changes the segments 132 from an off state (the white portion in the figure) to a lit state (the gray portion in the figure) from the left side of the screen to the right side. Alternatively, the amount of charging power may be displayed by changing the color of the segments 132.

[0035] The power consumption display unit 140 is a display unit that indicates the amount of power consumed per unit time by the power consumption device 20 during regenerative braking in which regenerative power is generated by the motor 12. The power consumption display unit 140 includes a plurality of segments 142 as a scale for indicating the amount of power consumption. Near the plurality of segments 142, a mark 144 extending along the arrangement direction of the plurality of segments 142 and characters (such as "consumption" in the figure) indicating that regenerative power is being consumed by the power consumption device 20 are displayed. The starting end 140a of the power consumption display unit 140 (one end of the segment 142 indicating that the power consumption is a value of 0) and the end 130a of the charging power display unit 130 (one end of the segment 132 corresponding to the specified value of the upper limit value of the battery 10) are arranged adjacent to each other. Thus, the charging power display unit 130 and the power consumption display unit 140 are arranged continuously. The greater the power consumption per unit time, the more the control device 30 turns the segment 142 from the off state ( Figure 3 The white part) changes to a lit state ( Figure 5 as well as Figure 6 In addition, the magnitude of the power consumption may be displayed by changing the color of the segment 142.

[0036] The display screen 100 during regenerative braking will be described in detail with reference to the drawings. Figure 4 Is to express Figure 3 The illustrated example is an explanatory diagram of the charging power display unit 130 and the power consumption display unit 140 when the charging power per unit time is increased. Figure 5 It 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.

[0037] In the case where the driver steps on the brake pedal 52 more sharply, as shown in FIG. Figures 3 and 4 As shown by the change in , the regenerative power generated by the motor 12 increases, the above-mentioned charging power increases, and the right-hand segment 132 of the charging power display unit 130 changes to a lit state. In addition, when the driver further abruptly steps on the brake pedal 52, the regenerative power exceeds the upper limit of the battery 10, and the remaining regenerative power is consumed by the power consumption device 20. As a result, Figures 4 and 5As shown by the change in , the segment 142 included in the power consumption display unit 140 changes to a lit state after exceeding the end 130a of the charging power display unit 130. This allows the driver to identify the amount of charging power or power consumption per unit time corresponding to the current amount of depression on the brake pedal 52. In this embodiment, the end 130a of the charging power display unit 130 and the beginning 140a of the power consumption display unit 140 are arranged adjacent to and continuously with each other. This allows the relationship between charging and consumption to be understood as a continuous series of states. For example, the driver can easily identify when the remaining regenerative power begins to be consumed as power.

[0038] As described above, the upper limit value of the battery 10 may change from a predetermined value depending on various conditions such as the charge rate and temperature. Therefore, when the upper limit value of the battery 10 decreases from the predetermined 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 6 130 and the power consumption display unit 140 when the upper limit value of the charging power of the battery 10 decreases from the prescribed value. As shown in the figure, when the upper limit value of the charging power of the battery 10 decreases from the prescribed value, the control device 30 does not display the segment 132 (in the Figure 6 In the example, the rightmost segment 132 on the screen is illuminated. Alternatively, the color of the segment 132 corresponding to the reduction amount may be displayed in a different color than the other segments 132. Furthermore, if power consumption is present, the control device 30 sequentially illuminates the segments 142 of the power consumption display unit 140 from the left. This allows the driver to easily recognize that the upper limit value of the battery 10 has decreased from the specified value.

[0039] At the same time, control device 30 displays an icon 160 on display screen 100 indicating that the upper limit value of the charging power of battery 10 has decreased from a predetermined value. When the upper limit value decreases from the predetermined value, icon 160 may change from an off state to an illuminated state, or may flash. This allows the driver to more easily recognize that the upper limit value of battery 10 has decreased from the predetermined value.

[0040] Furthermore, the control device 30 changes the display mode of the display screen 100 as compared to the non-charging mode as described below while the regenerative power is being charged to the battery 10. For example, the control device 30 changes the display mode of the display screen 100 as compared to the non-charging mode. Figure 3 The arrow 152 is displayed by blinking, changing the color of the line, or switching the line type to a broken line and rotating the line. In addition, when discharging from the battery 10, the control device 30 displays the arrow 151 in the same way.

[0041] In addition, the control device 30 changes the Figure 3 The control device 30 may, for example, display the color of the illuminated segments 112 of the charging rate display 110 in a different color than when 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 charging rate of the battery 10 is increasing. Furthermore, the control device 30 may display the frame 111, each segment 112, and the ECO charging mark 114 of the charging rate display 110 by flashing them, or by changing the color of the line, or by switching the line type to a broken line and rotating the line. As described above, while the regenerative power is being charged to the battery 10, by changing the display of the arrow 152 and the charging rate display 110 relative to when not charging, the driver can easily recognize that the battery 10 is in a state where regenerative power can be charged by the current braking operation.

[0042] As described above, in the dump truck 1 of the embodiment, the control device 30 generates a display screen 100 including a charging power display unit 130 that displays the amount of charging power charged to the battery 10 in the regenerative power, and a consumed power display unit 140 that displays the amount of consumed power consumed by the power consuming device 20, and displays the display screen on the display device 40.

[0043] This configuration allows the driver to identify the amount of charging power or power consumption per unit time corresponding to the current amount of brake pedal 52 depressed, enabling the driver to appropriately adjust the amount of brake pedal 52 depressed based on the road conditions on which the dump truck 1 is traveling. More specifically, the driver can be aware of starting the application of the brake pedal 52 early, preventing the driver from abruptly depressing the brake pedal 52 and generating a large amount of regenerative power in a short period of time. In particular, dump trucks 1 often travel along defined routes such as mines. Therefore, intentionally starting the application of the brake pedal 52 early during deceleration is a convenient approach, effectively contributing to the efficient recovery of regenerative power. Furthermore, when the dump truck 1 is traveling downhill, the driver can be aware of the need to avoid intermittently pressing or releasing the brake pedal 52. In other words, the driver can be aware of the need to slowly and long-term depress the brake pedal 52 while traveling downhill, within a range that allows for charging of the battery 10, in order to gradually generate regenerative power.

[0044] Therefore, according to the dump truck 1 of the embodiment, the driver can be prompted to perform appropriate braking operations, thereby efficiently recovering the regenerative power generated by the driving motor 12. In addition, by being aware of slowly depressing the brake pedal 52, the load applied to the front wheels 3, rear wheels 4, and various structures of the dump truck 1 can also be reduced.

[0045] This concludes the description of the embodiment, but the present invention is not limited to this embodiment. 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 can also be applied to other work vehicles. Furthermore, a work vehicle to which the present invention is applied may also include an internal combustion engine and a generator driven by the power of the internal combustion engine, with the power generated by the generator supplied to the motor 12. Furthermore, a work vehicle to which the present invention is applied may also drive by outputting the power of the internal combustion engine to the drive wheels in addition to the power of the motor 12.

[0046] Alternatively, the dump truck 1 may be a tram-type dump truck capable of operating in a tram mode using power supplied from an overhead wire via a pantograph. In this case, if the power consumption device includes a structure capable of supplying a portion of the regenerated power to the overhead wire for consumption, the control device 30 may also display the power consumed per unit time supplied to the overhead wire on the display screen 100.

[0047] In addition, the charging power display unit 130 is not limited to the charging power per unit time, but can also display the charging power of any time period. The power consumption display unit 140 is not limited to the power consumption per unit time, but can also display the power consumption of any time period the same as the charging power display unit 130.

[0048] In addition, the shape and arrangement position of each segment in each display unit are not limited to Figures 3 to 6 The shape and configuration position shown. For example, Figures 3 to 6 In the example, the segments 112, 122, 132, and 142 are spaced apart from each other, but the segments may be connected to each other. In this case, lines indicating the divisions of the segments may be displayed.

[0049] In addition, the end 130a of the charging power display unit 130 and the starting end 140a of the power consumption display unit 140 may be connected. In addition, the arrangement relationship between the charging power display unit 130 and the power consumption display unit 140 may be arranged in parallel with each other, for example. Figures 3 to 6 The configuration relationships shown are different.

[0050] In addition, Figures 3 to 6 , an example of lighting up or extinguishing (or changing the color) the entire range within a segment is shown, but it is also possible to light up or extinguish (or change the color) only a part of the range within a segment according to the value to be displayed on each display unit.

[0051] Explanation of symbols

[0052] 1 dump truck,

[0053] 10 batteries,

[0054] 12 motors (electric motors),

[0055] 20 Power consumption devices,

[0056] 24 resistors,

[0057] 30 control devices,

[0058] 40 display devices,

[0059] 100 display screen,

[0060] 110 charging rate display unit,

[0061] 120 discharge power display unit,

[0062] 130 Charging power display unit,

[0063] 130a end,

[0064] 140a Beginning,

[0065] 140 power consumption display unit,

[0066] 160 icons.

Claims

1. A work vehicle comprising: Battery; an electric motor for driving, connected to the battery; an electric power consumption device capable of consuming regenerative electric power generated by the electric motor; a display device that displays various information; as well as a control device that controls the electric motor, the power consumption device, and the display device, It is characterized by: The control device generates a display screen including a charging power display unit and a power consumption display unit, and displays the display screen on the display device. The charging power display unit displays the amount of charging power for charging the battery in the regenerative power, and the power consumption display unit displays the amount of power consumed by the power consuming device.

2. The work vehicle according to claim 1, characterized in that: The charging power display unit and the consumed power display unit are arranged continuously.

3. The work vehicle according to claim 1, characterized in that: The control device changes a display range of the charging power displayed on the charging power display unit according to an amount of decrease when an upper limit value of the electric power that can be charged to the battery decreases from a predetermined value.

4. The work vehicle according to any one of claims 1 to 3, characterized in that: When the upper limit of the electric power that can be charged to the battery decreases from a predetermined value, the control device displays an icon indicating that the upper limit decreases on the display screen.

5. The work vehicle according to claim 1, wherein: The control device generates a display screen further including a charge rate display unit displaying a current charge rate of the battery, and changes a display mode of the charge rate display unit when the battery is being charged with the regenerative electric power compared to when the battery is not being charged.

Images