Dump truck

Abstract

To provide a dump truck capable of reducing a fuel consumption by suppressing the output of an auxiliary power generator even when the regenerative electric power of a travel motor falls below the electric power required by auxiliary machine devices.SOLUTION: A dump truck includes: a main power generator 2 and an auxiliary power generator 14 which are driven by an engine 1; a travel inverter 9 for supplying the electric power generated by the main power generator 2 to a travel motor 3; an auxiliary machine inverter 12 for supplying the electric power generated by the auxiliary power generator 14 to auxiliary machine devices 13a to 13c; a DC-DC converter 10 for supplying regenerative electric power of the travel motor 3 to the auxiliary machine devices 13a to 13c; and a control unit 20 for controlling the main power generator 2, auxiliary power generator 14, travel inverter 9, auxiliary machine inverter 12 and DC-DC converter 10. The control unit 20 controls the travel inverter 9 so that the regenerative electric power is increased when the regenerative electric power is lower than the electric power required by the auxiliary machine devices 13a to 13c.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a dump truck equipped with an electric drive system. [Background technology]

[0002] In mines, many dump trucks with load capacities of over 100 tons are in operation to transport ore and stripped soil from loading sites to dump sites. The route from the loading site to the dump site is predetermined, and dump trucks repeatedly travel the same route back and forth. Multiple dump trucks of the same size travel along a single route, operating 24 hours a day. For large dump trucks that operate for long periods of time and in multiple units, transport efficiency, expressed in terms of the amount of work (energy) per unit cost (initial cost + running cost), is important. Therefore, in order to improve transport efficiency, various measures are implemented to minimize initial costs and reduce running costs. Reducing fuel consumption is an effective way to reduce running costs. Therefore, a drive system that is highly efficient and requires low maintenance costs is required. One such drive system is the electric drive system. While mechanical drive systems transmit engine power to tires via a torque converter and a transmission, electric drive systems use an engine to drive a generator, which then uses the generated electricity to drive a traction motor connected to the tire axle. Electric drive systems are driven by a highly efficient electric motor and can operate the engine at an operating point with high combustion efficiency, which is expected to reduce fuel consumption. Furthermore, electric drive systems are expected to further reduce fuel consumption by utilizing regenerative power obtained by generating electrical braking force with the traction motor on the many slopes (downhill slopes) found in mines. Note that typical electric vehicles are typically equipped with a secondary battery, and the regenerative power generated during the aforementioned electric braking can be charged into the secondary battery and used as discharge energy to drive the vehicle during normal driving. Meanwhile, Patent Document 1, for example, is a prior art document disclosing an electric drive system for a dump truck that does not have a secondary battery.The electric drive system described in Patent Document 1 comprises a first generator (main generator) that supplies power to the traction motor (main engine), a second generator (auxiliary generator) that supplies power to the auxiliary equipment, and a DC-DC converter provided in a circuit that connects the DC section on the main engine side and the DC section on the auxiliary equipment side.By supplying regenerative power from the traction motor generated during electric braking of the vehicle to the auxiliary equipment side via the DC-DC converter, the output of the auxiliary generator can be suppressed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 047270 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned conventional technology, the regenerative power generated when the vehicle is electrically braked is mainly used to drive auxiliary equipment such as the motor, generator, and various cooling blowers, making it possible to reduce fuel consumption accordingly. However, if the power required by the auxiliary equipment exceeds the regenerative power of the vehicle, the shortfall must be made up by an auxiliary generator, and it is not possible to reduce fuel consumption accordingly.

[0005] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a dump truck that can reduce fuel consumption by suppressing the output of the auxiliary generator even when the regenerative power of the traveling motor is lower than the power required by the auxiliary equipment. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention provides a dump truck including a vehicle body, a traveling motor that drives the vehicle body to travel, an auxiliary device including a cooling blower, a traveling operation device that instructs the traveling operation of the vehicle body, an engine, a main generator and an auxiliary generator driven by the engine, a traveling inverter that supplies power generated by the main generator to the traveling motor, an auxiliary inverter that supplies power generated by the auxiliary generator to the auxiliary device, a DC-DC converter that supplies regenerative power of the traveling motor to the auxiliary device, and a control device that controls the main generator, the auxiliary generator, the traveling inverter, the auxiliary inverter, and the DC-DC converter, wherein the control device controls the traveling inverter so that the regenerative power increases when the regenerative power falls below the power required by the auxiliary device.

[0007] According to the present invention configured as described above, when the regenerative power of the traction motor falls below the power required for the auxiliary devices, the regenerative power is increased to the extent that it does not affect the running of the vehicle, and the proportion of the power required for the auxiliary devices that can be covered by the regenerative power of the traction motor increases. This suppresses the output of the auxiliary generator, making it possible to reduce fuel consumption. [Effects of the Invention]

[0008] According to the present invention, in a dump truck equipped with an electric drive system, even when the regenerative power of the traveling motor is less than the power required by the auxiliary equipment, it is possible to reduce fuel consumption by suppressing the output of the auxiliary generator. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating a configuration of a dump truck. [Figure 2] FIG. 1 is a diagram showing the configuration of an electric drive system according to the prior art. [Figure 3] 1 is a diagram showing a configuration of an electric drive system according to an embodiment of the present invention. [Figure 4] FIG. 3 is a block diagram showing the processing of the control device. [Figure 5] FIG. 4 is a block diagram showing the processing of a regenerative power determination unit. [Figure 6] FIG. 4 is a block diagram showing the processing of a regenerative power compensation unit. [Figure 7] FIG. 2 is a block diagram showing the processing of a DC-DC converter control unit. [Figure 8] 10 is a flowchart showing the processing of the control device. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In each drawing, the same elements are designated by the same reference numerals, and duplicated explanations will be omitted as appropriate.

[0011] FIG. 1 shows the configuration of a mining dump truck according to an embodiment of the present invention. In FIG. 1, the mining dump truck includes a vehicle body 40, an engine 1 that serves as a power source for a main generator 2 and an auxiliary generator 14 (shown in FIG. 3), which will be described later, a loading platform 7 attached to the upper rear of the vehicle body 40 so as to be rotatable in the vertical direction, and a driver's seat 6 provided at the upper front of the vehicle body 40. A pair of left and right driven wheels 4L, 4R are disposed at the lower front of the vehicle body 40, and a pair of left and right drive wheels 5L, 5R are disposed at the lower rear of the vehicle body 40. The drive wheels 5L, 5R are driven by a travel motor 3. The mining dump truck repeatedly performs a series of work cycles: loading earth and sand at a loading site, traveling from the loading site to a dumping site, discharging the earth and sand at the dumping site, and traveling from the dumping site to the loading site.

[0012] The configuration of a conventional electric drive system is shown in Figure 2. In Figure 2, the electric drive system 100X includes a main generator (MG) 2 and a sub generator (SG) 14 driven by an engine 1, a traction motor 3 that drives the drive wheels 5L and 5R, an accessory motor 13, a traction inverter 9, an accessory inverter 12, a rectifier 8, an auxiliary rectifier 11, a discharge resistor 15, a DC-DC converter 10, and a control device 20X that controls the main generator 2, the sub generator 14, and the DC-DC converter 10.

[0013] The main generator 2 and the auxiliary generator 14 convert the rotational energy of the engine 1 into electrical energy (AC power). The rectifier 8 rectifies the AC power supplied from the main generator 2 into DC power and supplies it to the traction inverter 9. The traction inverter 9 converts the DC power supplied from the rectifier 8 into AC power and supplies it to the traction motor 3.

[0014] Auxiliary generator 14 is used as a power source for an auxiliary system that drives auxiliary equipment such as cooling equipment. Auxiliary rectifier 11 converts AC power supplied from auxiliary generator 14 into DC power and supplies it to auxiliary inverter 12. Auxiliary inverter 12 converts DC power supplied from auxiliary rectifier 11 into AC power and supplies it to auxiliary motor 13. Auxiliary motor 13 drives cooling equipment (not shown), such as a blower. Note that while FIG. 2 shows only one pair of auxiliary inverter 12 and auxiliary motor 13 as the auxiliary system, an actual vehicle will have multiple devices equivalent to the auxiliary equipment, and therefore multiple auxiliary inverters and auxiliary motors with different capacities will be installed.

[0015] The control device 20X drives the auxiliary motor 13 by reducing the regenerative power generated by the traction motor 3 during electric braking of the vehicle using the DC-DC converter 10 and supplying the power to the auxiliary inverter 12. This reduces the power of the engine 1 consumed to drive the auxiliary generator 14, thereby improving the fuel efficiency of the engine 1.

[0016] Note that the regenerative power from the traction motor 3 is usually greater than the power required by the auxiliary equipment 13 and cannot be consumed by simply supplying power to the auxiliary equipment via the DC-DC converter 10. Specifically, the regenerative power (approximately several thousand kW) of the traction motor in a dump truck is several tens of times the power required by the auxiliary equipment 13 (approximately 100 kW). Therefore, by dissipating the surplus regenerative power using the discharge resistor 15, it is possible to obtain sufficient electrical braking force from the traction motor 3. In other words, during normal electrical braking, the regenerative power alone can cover the power required by the auxiliary equipment 13, eliminating the need for power generation by the auxiliary generator 14. However, the fuel economy improvement achieved by stopping the power generation of the auxiliary generator 14 during normal electrical braking is only a few percent compared to conventional vehicle models. Furthermore, because the frequency and duration of regeneration vary depending on the driving environment, this fuel economy improvement effect compared to conventional vehicle models cannot be consistently achieved.

[0017] Therefore, a method for achieving further fuel economy improvement effects in the electric drive system of this embodiment will be described.

[0018] In a dump truck, the regenerative power generated during normal vehicle braking is much larger than the power required by the auxiliary equipment 13. Therefore, the power required by the auxiliary equipment 13 can be met solely by the regenerative power, and during this time, the output of the auxiliary generator 14 can be kept substantially zero. However, depending on the traveling state, the regenerative power may fall short of the power required by the auxiliary equipment 13. In such cases, the shortfall in power must be generated by the auxiliary generator 14. Therefore, by suppressing the output of the auxiliary generator 14 when the regenerative power falls short of the power required by the auxiliary equipment 13, it is possible to reduce fuel consumption by that amount. Furthermore, during coasting (for example, when descending a slope), the regenerative operation of the travel motor 3 is not performed except when braking is performed by auto-retard control, and the power required by the auxiliary equipment 13 must be met solely by the power generated by the auxiliary generator 14.

[0019] Here, the power required by auxiliary device 13 (about 100 kW) is much smaller than the regenerative power (several thousand kW) during normal vehicle braking, so even if the regenerative power is increased to the power required by auxiliary device 13 during vehicle braking or coasting when the regenerative power is small, there is almost no effect on the vehicle's running operation. Therefore, by generating regenerative power equivalent to the power required by auxiliary device 13 and suppressing the output of auxiliary generator 14 to approximately zero during vehicle braking or coasting when the regenerative power is small, a further improvement in fuel efficiency can be achieved.

[0020] The configuration of the electric drive system in this embodiment is shown in Figure 3. In Figure 3, the auxiliary device is made up of multiple auxiliary motors 13a-13c. The electric drive system 100 includes multiple auxiliary inverters 12a-12c that supply power to the multiple auxiliary motors 13a-13c, respectively, a voltage sensor 31 that detects the voltage of the auxiliary side DC bus 17, and a current sensor 32 that detects the output current of the DC-DC converter 10. Signals from the voltage sensor 31 and the current sensor 32 are input to the control device 20.

[0021] Fig. 4 is a block diagram showing the processing of the control device 20. In Fig. 4, the control device 20 has a regenerative power determination unit 21, a regenerative power compensation unit 22, a running inverter control unit 23, and a DC-DC converter control unit 24. The control device 20 is composed of a controller having a calculation function, an input / output interface that inputs and outputs signals to and from external devices, and the functions of each unit are realized by executing a program stored in a storage device such as a ROM.

[0022] The regenerative power determination unit 21 determines the power (regenerative power) to be regenerated by the traction motor 3 based on the vehicle speed input from the vehicle speed sensor 41, the signal input from the accelerator 51 (accelerator signal), the signal input from the brake 52 (brake signal), and the signal input from the forward / reverse switch 53 (forward / reverse switch signal), and outputs the determined power to the regenerative power compensation unit 22. The regenerative power compensation unit 22 compensates for the regenerative power according to the power required by the accessories, and outputs the compensated regenerative power to the traction inverter control unit 23 and the DC / DC converter control unit 24.

[0023] The running inverter control unit 23 outputs a control signal (running inverter control signal) to the running inverter 9 to generate a braking force according to the compensated regenerative power. The DC-DC converter control unit 24 outputs a control signal (DCDC converter control signal) according to the compensated regenerative power, the auxiliary side DC voltage, and the DC-DC converter current to the DC-DC converter 10.

[0024] In the normal traveling mode in which the traction motor 3 is powered, no regenerative power is generated, so the regenerative control shown in Fig. 4 is not performed, and instead the auxiliary side DC voltage is controlled by controlling the field current of the auxiliary generator 14. Here, if the regenerative power of the traction motor 3 is greater than the power required by the auxiliary device 13, the power required by the auxiliary device 13 can be met by the regenerative power alone, and the output of the auxiliary generator 14 becomes approximately zero.

[0025] FIG. 5 is a block diagram showing the processing of regenerative power determination unit 21. In FIG. 5, regenerative power determination unit 21 includes opening degree determination unit 21a, regeneration determination unit 21b, and regenerative power calculation unit 21c. Opening degree determination unit 21a determines the opening degrees of accelerator 51 and brake 52 based on an accelerator signal and a brake signal, and outputs the determination result to regenerative power determination unit 21b. Regenerative power determination unit 21b determines whether regeneration is possible based on the opening degree determination result of accelerator 51 and brake 52 and a forward / reverse switch signal, and outputs the determination result to regenerative power calculation unit 21c. Specifically, it is determined that regeneration is possible when the opening degree of accelerator 51 is zero, the opening degree of brake 52 is greater than zero, and the vehicle speed is equal to or greater than a predetermined value (during vehicle braking), or when the opening degrees of accelerator 51 and brake 52 are zero and the vehicle speed is equal to or greater than a predetermined value (during coasting).

[0026] The regenerative power calculation unit 21c calculates the regenerative power (braking energy) of the traction motor 3 based on the regeneration possibility determination result and the vehicle speed, and outputs the calculated amount to the regenerative power compensation unit 22. When the openings of the accelerator 51 and brake 52 are zero (during coasting), the regenerative power calculation unit 21c calculates the regenerative power to be zero regardless of the vehicle speed. Note that the method for determining the regenerative power is not limited to the method shown in FIG. 5. For example, the target deceleration of the vehicle may be calculated from the vehicle speed and brake signal, and the regenerative power may be obtained from this value, or it may be obtained by searching a table using the vehicle speed, accelerator signal, and brake signal.

[0027] Fig. 6 is a block diagram showing the processing of the regenerative power compensation unit 22. In Fig. 6, the regenerative power compensation unit 22 has an added regenerative power calculation unit 22a, an added regenerative power upper limit value calculation unit 22b, an added regenerative power limiting unit 22c, a regenerative power adding unit 22d, and a regenerative power limiting unit 22e.

[0028] The additional regenerative power calculation unit 22a calculates the regenerative power shortage by subtracting the regenerative power from the power required by the auxiliary devices 13a to 13c (auxiliary required power), as additional regenerative power, and outputs it to the additional regenerative power limiting unit 22c. The additional regenerative power upper limit value calculation unit 22b calculates an additional regenerative power upper limit value based on the auxiliary required power and the regenerative power, and outputs it to the additional regenerative power limiting unit 22c.

[0029] The added regenerative power limiting unit 22c limits the added regenerative power to an added regenerative power upper limit value or less and outputs the limit to the regenerative power adding unit 22d. This prevents the vehicle's traveling operation from being affected by excessively added regenerative power. The regenerative power adding unit 22d adds the limited added regenerative power to the regenerative power and outputs the result to the regenerative power limiting unit 22e. The regenerative power limiting unit 22e limits the regenerative power in accordance with the output upper limit of the DC-DC converter 10 and outputs the limited regenerative power to the traveling inverter control unit 23 and the DC-DC converter control unit 24.

[0030] Fig. 7 is a block diagram showing the processing of the DC-DC converter control unit 24. The DC-DC converter control unit 24 performs feedback control to make the voltage of the auxiliary side DC bus 17 coincide with a predetermined auxiliary side DC voltage command value. In Fig. 7, the DC-DC converter control unit 24 has a current command value calculation unit 24a, a current upper limit value calculation unit 24b, a current command value limiting unit 24c, and a current control unit 24d.

[0031] The current command value calculation unit 24a calculates a DC-DC converter current command value by performing proportional-plus-integral calculation on the deviation between the auxiliary-side DC voltage command value and the auxiliary-side DC voltage, and outputs the calculated value to the current command value limiting unit 24c. Note that the calculation process of the current command value calculation unit 24a is not limited to proportional-plus-integral calculation.

[0032] The current upper limit value calculation unit 24b calculates the current upper limit value of the DC-DC converter 10 by dividing the compensated regenerative power by the main machine side DC voltage command value, and outputs the calculated current upper limit value to the current command value limiting unit 24c.

[0033] The current command value limiting unit 24c limits the DC-DC converter current command value to a current upper limit value or less and outputs it to the current control unit 24d. The current control unit 24d generates a control signal (DCDC converter control signal) by performing proportional and integral calculation on the deviation between the DC-DC converter current command value after the limiting and the DC-DC converter current, and outputs it to the DC-DC converter 10. Note that the calculation processing of the current command value calculation unit 24a is not limited to proportional and integral calculation.

[0034] Fig. 8 is a flowchart showing the processing of the control device 20. The control device 20 repeatedly executes the processing shown in Fig. 8 at a predetermined cycle. Each step will be explained below in order.

[0035] The control device 20 first determines whether the vehicle is in a running state in which regenerative power can be obtained (regeneration is possible) (step S1). A running state in which regeneration is possible here refers to when the vehicle is braking or coasting. If the determination result in step S1 is NO (regeneration is not possible), the flow ends.

[0036] If the determination result in step S1 is YES (regeneration is possible), the regenerative power is calculated (step S2).

[0037] Following step S2, the power shortage (regenerative power shortage) obtained by subtracting the regenerative power from the power required by the auxiliary devices 13a to 13c is calculated as additional regenerative power (step S3).

[0038] Following step S3, the additional regenerative power calculated in step S3 is limited to an upper limit value or less (step S4).

[0039] Following step S4, the additional regenerative power calculated in step S4 is added to the regenerative power calculated in step S2 (step S5).

[0040] Following step S5, the regenerative power calculated in step S5 is limited to an upper limit value or less (step S6).

[0041] Following step S6, the driving inverter 9 is controlled in accordance with the regenerative power calculated in step S6 (step S7).

[0042] Following step S7, the DC-DC converter 10 is controlled so that the regenerative power of the main-side DC bus 16 is supplied to the auxiliary-side DC bus 17 (step S8), and the flow ends.

[0043] (summary) In this embodiment, the dump truck includes a vehicle body 40, a traveling motor 3 that drives the vehicle body 40 to travel, auxiliary equipment devices 13a to 13c including a cooling blower, traveling operation devices 51, 52 that instruct the traveling operation of the vehicle body 40, an engine 1, a main generator 2 and an auxiliary generator 14 driven by the engine 1, a traveling inverter 9 that supplies power generated by the main generator 2 to the traveling motor 3, an auxiliary equipment inverter 12 that supplies power generated by the auxiliary generator 14 to the auxiliary equipment devices 13a to 13c, a DC-DC converter 10 that supplies regenerative power of the traveling motor 3 to the auxiliary equipment devices 13a to 13c, and a control device 20 that controls the main generator 2, the auxiliary generator 14, the traveling inverter 9, the auxiliary equipment inverter 12, and the DC-DC converter 10.When the regenerative power falls below the power required by the auxiliary equipment devices 13a to 13c, the control device 20 controls the traveling inverter 9 so that the regenerative power increases.

[0044] According to the present embodiment configured as described above, when the regenerative power of the traction motor 3 falls below the power required by the auxiliary devices 13a to 13c, the regenerative power is increased to the extent that it does not affect the traveling operation of the vehicle, and a proportion of the power required by the auxiliary devices 13a to 13c that can be met by the regenerative power of the traction motor 3 increases. This suppresses the output of the auxiliary generator 14, making it possible to reduce fuel consumption.

[0045] Furthermore, in this embodiment, when the regenerative power of the traction motor 3 falls below the power required by the auxiliary devices 13a to 13c, the control device 20 controls the traction inverter 9 so that the regenerative power matches the required power. This allows the power required by the auxiliary devices 13a to 13c to be met solely by the regenerative power of the traction motor 3, making it possible to suppress the output of the auxiliary generator 14 to approximately zero.

[0046] Alternatively, the dump truck in this embodiment is equipped with a vehicle speed sensor 41 that detects the vehicle speed of the vehicle body 40, and the travel operation devices 51, 52 have an accelerator 51 that instructs the vehicle body 40 to increase its speed and a brake 52 that instructs the vehicle body 40 to decelerate, and the control device 20 controls the travel inverter 9 so that regenerative power is generated by the travel motor 3 when the accelerator 51 and the brake 52 are not being operated and the vehicle speed is equal to or greater than a predetermined value. As a result, it is possible to reduce fuel consumption by suppressing the output of the auxiliary generator 14 when the dump truck is coasting.

[0047] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those having all of the described configurations. [Explanation of symbols]

[0048] 1...engine, 2...main generator, 3...travel motor, 4L, 4R...driven wheels, 5L, 5R...driving wheels, 6...driver's seat, 7...loading platform, 8...rectifier, 9...travel inverter, 10...DC-DC converter, 11...auxiliary rectifier, 12, 12a to 12c...auxiliary inverter, 13, 13a to 13b...auxiliary motor (auxiliary device), 14...auxiliary generator, 15...discharge resistor, 16...main engine side DC bus, 17...auxiliary side DC bus, 20, 20X...control device, 21...regenerative power determination unit, 21a...opening determination unit, 21b...regeneration determination unit, 21c...regenerative power calculation unit, 22...regenerative power compensation unit, 22a...regenerative power calculation unit, 22b...regenerative power upper limit value calculation unit, 22c...regenerative power limiting unit, 22d...regenerative power adding unit, 22e...regenerative power limiting unit, 23...driving inverter control unit, 24...DCDC converter control unit, 24a...current command value calculation unit, 24b...current upper limit value calculation unit, 24c...current command value limiting unit, 24d...current control unit, 31...voltage sensor, 32...current sensor, 40...vehicle body, 41...vehicle speed sensor, 51...accelerator (driving operation device), 52...brake (driving operation device), 53...forward / reverse switch, 100, 100X...electric drive system.

Claims

1. The car body and a traction motor that drives the vehicle body to travel and generates regenerative power; an auxiliary device including a cooling blower; a travel operation device that instructs the travel operation of the vehicle body; The engine and a main generator and an auxiliary generator driven by the engine; a traveling inverter that supplies the electric power generated by the main generator to the traveling motor; an auxiliary inverter that supplies the electric power generated by the auxiliary generator to the auxiliary device; a DC-DC converter that supplies regenerative power of the traction motor to the auxiliary device; A dump truck including a control device that controls the main generator, the auxiliary generator, the traveling inverter, the auxiliary inverter, and the DCDC converter, When the regenerative power is greater than the power required by the auxiliary device, the control device controls the DCDC converter so that the power required by the auxiliary device is met by the regenerative power, and when the vehicle is in a running state in which regeneration is possible and the regenerative power is less than the power required by the auxiliary device, the control device controls the running inverter so that the regenerative power increases below an upper limit value set so as not to affect the running operation of the traction motor. A dump truck characterized by:

2. The dump truck according to claim 1, When the regenerative power falls below the required power of the auxiliary device, the control device controls the traveling inverter so that the regenerative power matches the required power. A dump truck characterized by:

3. The dump truck according to claim 1, a vehicle speed sensor for detecting a vehicle speed, which is the speed of the vehicle body; the travel operation device has an accelerator that instructs the vehicle body to accelerate and a brake that instructs the vehicle body to decelerate, The control device controls the traveling inverter so that the regenerative power is generated when the accelerator and the brake are not operated and the vehicle speed is equal to or greater than a predetermined value. A dump truck characterized by:

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