dump truck

Abstract

To provide a dump truck improved in fuel efficiency by improving utilization efficiency of regenerative energy during braking.SOLUTION: A dump truck is equipped with: a vehicle body that travels by rotation of tires; an engine that generates driving force; a generator that generates electric power by driving force generated by the engine; a travelling motor that rotates the tires by electric power generated by the generator; a fan motor that receives supply of electric power and rotates a cooling fan; and a controller that controls driving of the fan motor. The controller, when the tires are not braked (S11:No), supplies the fan motor with first electric power generated by the generator (S17), and when the tires are braked (S11:Yes), supplies the fan motor with second electric power larger than the first electric power, of regenerative electric power generated by the travelling motor (S14 / S15).SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] This invention relates to a dump truck that utilizes regenerative energy. [Background technology]

[0002] A dump truck has been known for some time, comprising a vehicle body that moves by the rotation of tires, an engine that generates driving force, a generator that generates electricity using the engine's driving force, a drive motor that rotates the tires using the electricity generated by the generator, and a fan motor that rotates a cooling fan in response to the power supply.

[0003] Furthermore, in a dump truck with the above configuration, there is a technology that stores regenerative power generated during braking in a battery and drives the drive motor with power discharged from the battery during acceleration (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2000-299901 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, significant energy loss occurs during the charging and discharging of batteries. Therefore, the configuration described in Patent Document 1 does not effectively utilize regenerative energy during braking, resulting in low fuel consumption efficiency.

[0006] This invention has been made in view of the above-described circumstances, and its purpose is to provide a dump truck with improved fuel efficiency by increasing the utilization rate of regenerative energy during braking. [Means for solving the problem]

[0007] To achieve the above object, the present invention provides a vehicle body that travels by the rotation of tires, an engine that generates driving force, a generator that generates electricity by the driving force of the engine, a traveling motor that rotates the tires by the electricity generated by the generator, and a cooling fan that rotates upon receiving power supply multiple objects to be cooled, In a dump truck including a fan motor and a controller that controls the driving of the fan motor, when the tire is not being braked, the controller causes the generator to generate Electricity First power In size said multiple fan motor Each and supplies it to the fan motor. When the tire is being braked, If it is determined that the regenerative power generated by the drive motor is less than the sum of the second powers, which are predetermined for each fan motor and are greater than the first power, then the first power from the regenerative power generated by the drive motor is supplied to each of the multiple fan motors. If it is determined that the regenerative power generated by the drive motor is equal to or greater than the sum of the power, of the regenerative power generated by the traveling motor, the Record number second power multiple fan motor Each is supplied to the fan motor. This is the gist of the present invention.

Advantages of the Invention

[0008] According to the present invention, the regenerative energy during braking can be effectively utilized to improve fuel efficiency. In addition, problems, configurations, and effects other than those described above will be clarified by the description of the following embodiments.

Brief Description of the Drawings

[0009] [Figure 1] It is a side view of a dump truck according to this embodiment. [Figure 2] It is a circuit diagram of a drive circuit mounted on a dump truck. [Figure 3] It is a hardware configuration diagram of a dump truck. [Figure 4] It is a flowchart of charge / discharge control processing. [Figure 5] It is a diagram showing the transition of measured temperature when the cooling fan is rotated in the low output mode. [Figure 6] It is a diagram showing the transition of measured temperature when the cooling fan is not rotated in the low output mode. [Figure 7]This is a flowchart of the process executed by the controller according to Modification Example 1, instead of the process enclosed by the dashed line in Figure 4. [Figure 8] This figure shows the drive circuit according to modified example 2. [Modes for carrying out the invention]

[0010] An embodiment of the dump truck according to the present invention will be described with reference to the drawings. Figure 1 is a side view of the dump truck 1 according to this embodiment. In this specification, the front, rear, left, and right directions are based on the viewpoint of the operator riding in and operating the dump truck 1, unless otherwise specified.

[0011] As shown in Figure 1, the dump truck 1 according to this embodiment mainly comprises a body frame 2, a pair of front tires 3L, 3R rotatably supported at both left and right ends of the front of the body frame 2, a pair of rear tires 4L, 4R rotatably supported at both left and right ends of the rear of the body frame 2, a cargo bed 5 that is raised and lowered on the body frame 2, and a cab 6 in which an operator who operates the dump truck 1 sits.

[0012] The pair of front tires 3L and 3R are steering wheels whose steering angle changes according to the operator's steering input. On the other hand, the pair of rear tires 4L and 4R are drive wheels that rotate when the driving force from the drive motors 18L and 18R (see Figure 2) is transmitted to them. The dump truck 1 is equipped with a pair of drive motors 18L and 18R to independently transmit driving force to each of the rear tires 4L and 4R.

[0013] The cargo bed 5 moves up and down around the hinge pin 8 at the rear of the vehicle frame 2 by the extension and retraction of the hoist cylinders 7L and 7R. One end of the hoist cylinders 7L and 7R is connected to the vehicle frame 2, and the other end is connected to the cargo bed 5. They extend and retract by receiving hydraulic fluid from a hydraulic pump (not shown). When the hoist cylinders 7L and 7R are extended, the cargo bed 5 stands upright, and when the hoist cylinders 7L and 7R are retracted, the cargo bed 5 collapses.

[0014] The cab 6 is located at the left end of the deck 9 at the front of the vehicle frame 2. The cab 6 forms the driver's cabin where the operator who operates the dump truck 1 sits. Inside the cab 6 is the control device 6a (see Figure 3) for operating the dump truck 1. By operating the control device 6a from inside the cab 6, the dump truck 1 moves (accelerates, brakes, turns) and the cargo bed 5 rises and falls.

[0015] The operating device 6a outputs an operation signal corresponding to the user's operation to the controller 30 (see Figure 3), which will be described later. The operating device 6a includes, for example, an accelerator pedal, a brake pedal, a steering wheel, and a driving lever.

[0016] The accelerator pedal is a control device that instructs the dump truck 1 to accelerate. The brake pedal is a control device that instructs the dump truck 1 to brake. The steering wheel is a control device that instructs the dump truck 1 to turn in a specific direction. The driving lever is a control device that instructs the dump truck 1 to move in a specific direction (forward position, reverse position, neutral position) when the accelerator pedal is pressed.

[0017] Furthermore, a drive circuit 10 for driving the dump truck 1 is located below the deck 9. In addition, a grid box 20 (see Figure 2) and a blower (not shown) that supplies cooling air to the grid box 20 are installed on the deck 9.

[0018] Figure 2 is a circuit diagram of the drive circuit 10 installed in the dump truck 1. The drive circuit 10 mainly consists of, for example, an engine 11, a radiator 12, a main generator 13, an auxiliary generator 14, rectifiers 15 and 16, inverters 17L and 17R, travel motors 18L and 18R, a chopper 19, a grid box 20, a step-down device 21, inverters 22A, 22B, 22C and 22D, fan motors 23A, 23B, 23C and 23D, and cooling fans 24A, 24B, 24C and 24D.

[0019] Engine 11 generates driving force to drive the dump truck 1 by burning fuel. The main generator 13 and auxiliary generator 14 (hereinafter collectively referred to as "generators 13 and 14") are connected to the output shaft of engine 11. Generators 13 and 14 receive the driving force from engine 11 and generate three-phase alternating current power. Rectifier 15 converts the three-phase alternating current power output from the main generator 13 into direct current power and outputs it to inverters 17L and 17R. Rectifier 16 converts the three-phase alternating current power output from the auxiliary generator 14 into direct current power and outputs it to inverters 22A to 22D.

[0020] Inverters 17L and 17R convert the DC power output from the rectifier 15 into three-phase AC power and output it to the drive motors 18L and 18R. The drive motors 18L and 18R rotate by receiving the three-phase AC power supplied from inverters 17L and 17R. The rotational driving force of the drive motors 18L and 18R is then transmitted to the rear tires 4L and 4R through a reduction gear (not shown), causing the dump truck 1 to move (accelerate).

[0021] On the other hand, when braking dump truck 1, the drive motors 18L and 18R operate as electric brakes. The drive motors 18L and 18R, operating as electric brakes, generate regenerative power and output it to inverters 17L and 17R. The inverters 17L and 17R convert the three-phase AC regenerative power output from the drive motors 18L and 18R into DC power and output it to the chopper 19 and the step-down device 21.

[0022] Chopper 19 supplies power output from inverters 17L and 17R to grid box 20 during regenerative braking of dump truck 1. Grid box 20 is a resistor that converts the regenerative power generated by the drive motors 18L and 18R into heat for consumption.

[0023] The step-down device 21 steps down the DC power generated by the travel motors 18L and 18R and converted by the inverters 17L and 17R and outputs it to inverters 22A to 22D. Inverters 22A to 22D convert the DC power output from the rectifier 16 or the step-down device 21 into three-phase AC power and output it to fan motors 23A to 23D.

[0024] Fan motors 23A to 23D (hereinafter sometimes collectively referred to as "fan motor 23") rotate by receiving three-phase AC power from inverters 22A to 22D. The rotational driving force of fan motors 23A to 23D is then transmitted to the cooling fans 24A to 24D, causing them to rotate (generate cooling air).

[0025] Multiple cooling fans 24A to 24D each generate cooling airflow directed towards different objects to be cooled. In this embodiment, the object to be cooled by cooling fan 24A (fan motor 23A) is the grid box 20, the object to be cooled by cooling fan 24B (fan motor 23B) is the travel motors 18L and 18R, the object to be cooled by cooling fan 24C (fan motor 23C) is the generators 13 and 14, and the object to be cooled by cooling fan 24D (fan motor 23D) is the radiator 12. However, the number and specific examples of objects to be cooled are not limited to the above example.

[0026] The drive circuit 10 also includes a plurality of temperature sensors 20a, 18a, 13a, and 12a (see Figure 3). The temperature sensors 20a, 18a, 13a, and 12a detect the temperature of the corresponding object to be cooled (i.e., the grid box 20, the travel motors 18L and 18R, the generators 13 and 14, and the radiator 12) (hereinafter referred to as "measured temperatures TA, TB, TC, and TD") and output a temperature signal indicating the detection result to the controller 30.

[0027] Figure 3 is a hardware configuration diagram of dump truck 1. Dump truck 1 includes a controller 30. The controller 30 includes a CPU (Central Processing Unit) 31 and memory 32. Memory 32 consists of, for example, ROM (Read Only Memory), RAM (Random Access Memory), HDD (Hard Disk Drive), or a combination thereof. The controller 30 performs the processing described later by having the CPU 31 read and execute program code stored in the ROM or HDD. RAM is used as a work area when the CPU 31 executes the program.

[0028] However, the specific configuration of the controller 30 is not limited to this and may be implemented using hardware such as an ASIC (Application Specific Integrated Circuit) or FPGA (Field-Programmable Gate Array).

[0029] The controller 30 controls the engine 11, generators 13 and 14, inverters 17L, 17R, 22A to 22D, and chopper 19 based on the operation signals output from the operating device 6a and the temperature signals output from the temperature sensors 20a, 18a, 13a, and 12a.

[0030] The controller 30 increases the rotational speed of the engine 11 in response to the accelerator pedal being pressed, and supplies the power generated by the main generator 13 to the drive motors 18L and 18R through the rectifier 15 and inverters 17L and 17R. The controller 30 also supplies the power generated by the auxiliary generator 14 to the fan motors 23A and 23D through the rectifier 16 and inverters 22A to 22D.

[0031] Furthermore, the controller 30 reduces the rotational speed of the engine 11 and activates the drive motors 18L and 18R as electric brakes when the brake pedal is pressed. Also, when the dump truck 1 is being braked, the controller 30 outputs the electricity generated by the drive motors 18L and 18R to the chopper 19 and the step-down device 21 via the inverters 17L and 17R. The electricity output to the step-down device 21 is then stepped down and supplied to the fan motors 23A and 23D via the inverters 22A and 22D. The electricity output to the chopper 19 is consumed by the grid box 20.

[0032] Furthermore, the controller 30 operates the fan motors 23A to 23D in one of several output modes (high output mode, medium output mode, low output mode). The high output mode is a mode in which the controller outputs a predetermined second power (PA, PB, PC, PD) for each fan motor 23A to 23D from the regenerative power generated by the travel motors 18L and 18R to the fan motors 23A to 23D. The medium output mode is a mode in which the controller outputs a predetermined first power (Pa, Pb, Pc, Pd) for each fan motor 23A to 23D from the regenerative power generated by the travel motors 19L and 18R or from the power generated by the auxiliary generator 14 to the fan motors 23A to 23D. The low output mode is a mode in which the controller outputs a predetermined third power (Pa', Pb', Pc', Pd') for each fan motor 23A to 23D from the power generated by the auxiliary generator 14 to the fan motors 23A to 23D.

[0033] For each of the fan motors 23A to 23D, the third power < first power < second power. Also, the first power (Pa, Pb, Pc, Pd) for each of the fan motors 23A to 23D may be the same value or different values. The same applies to the second power (PA, PB, PC, PD) and the third power (Pa', Pb', Pc', Pd'). Furthermore, the first power, second power, and third power for each of the fan motors 23A to 23D are pre-stored in memory 32.

[0034] Further, the first power (Pa, Pb, Pc, Pd) is the power to be supplied to the corresponding fan motors 23A to 23D in order to maintain the object to be cooled at the target temperature (TA tgt , TB tgt , TC tgt , TD tgt ). The target temperature (TA tgt , TB tgt , TC tgt , TD tgt ) of each object to be cooled is stored in the memory 32 in advance.

[0035] In addition, the controller 30 may increase or decrease the first power (Pa, Pb, Pc, Pd) so that the measured temperature T detected by the temperature sensors 20a, 18a, 13a, 12a approaches the target temperature T tgt . That is, the first power (Pa, Pb, Pc, Pd) may be a value selected from a predetermined range between the upper limit value and the lower limit value. In this case, the second power is greater than the upper limit value of the first power, and the third power is less than the lower limit value of the first power.

[0036] FIG. 4 is a flowchart of the charge and discharge control process. The controller 30 repeatedly executes the charge and discharge control process shown in FIG. 4 at predetermined time intervals, for example, while the engine 11 is driving.

[0037] First, the controller 30 determines whether or not the brake pedal is depressed (that is, the traveling motors 18L and 18R are generating regenerative power) based on the operation signal output from the operation device 6a (S11).

[0038] Next, when the controller 30 determines that the brake pedal is depressed (that is, during braking) (S11: Yes), it compares the regenerative power P generated by the traveling motors 18L and 18R with the total power P ALL of the second power of the fan motors 23A to 23D (S12). Further, when the controller 30 determines that the regenerative power P is greater than or equal to the total power P ALL (S12: Yes), it determines whether the surplus power P R is greater than 0 (S13). Note that the surplus power PR This is calculated from regenerative power P to total power P ALL This is the remainder after subtracting [amount].

[0039] Then, the controller 30 controls the surplus power P R If it is determined that the value is greater than 0 (S13: Yes), the fan motors 23A to 23D are operated in high-power mode, and the excess power P is supplied to the grid box 20 via the chopper 19. R (S14) The controller 30 supplies the surplus power P R If it is determined that the value is 0 (S13: No), the fan motors 23A to 23D are operated in high-power mode, while the surplus power P is supplied to the grid box 20. R We will not supply it (S15).

[0040] In other words, in steps S14 and S15, the controller 30 supplies the second power (PA, PB, PC, PD) of the regenerative power P generated by the travel motors 18L and 18R to the fan motors 23A to 23D. Furthermore, in step S14, the controller 30 supplies the remaining (surplus power P) of the regenerative power P after supplying it to the fan motors 23A to 23D. R ) is consumed by gridbox 20.

[0041] Furthermore, the controller 30 detects when the brake pedal is depressed and the regenerative power P is equal to the total power P. ALL If it is determined to be less than (S11: Yes & S12: No), the fan motors 23A to 23D are operated in medium output mode (S17). At this time, the controller 30 supplies the first power (PA, PB, PC, PD) of the regenerative power P generated by the drive motors 18L and 18R to the fan motors 23A to 23D.

[0042] Furthermore, if the controller 30 determines that the brake pedal is not pressed (i.e., not braking) (S11: No), it will use the measured temperatures TA, TB, TC, and TD of the object to be cooled detected by the temperature sensors 20a, 18a, 13a, and 12a, and the corresponding target temperature TA tgt , TB tgt , TCtgt , TD tgt Compare this with (S16).

[0043] Then, the controller 30 determines that the measured temperature TA of the grid box 20 detected by the temperature sensor 20a is equal to the target temperature TA. tgt If it is determined that the above conditions are met (S16: Yes), the fan motor 23A is operated in medium output mode (S17). At this time, the controller 30 supplies the first power Pa generated by the auxiliary generator 14 to the fan motor 23A.

[0044] Meanwhile, the controller 30 determines that the measured temperature TA of the grid box 20 detected by the temperature sensor 20a is equal to the target temperature TA. tgt If it is determined to be less than (S16: No), the fan motor 23A is operated in low-power mode (S18). That is, the controller 30 supplies the third power Pa' generated by the auxiliary generator 14 to the fan motor 23A.

[0045] The same applies to other cooling targets (radiator 12, generators 13 and 14, and drive motors 18L and 18R). In other words, the controller 30 checks which of the multiple cooling targets has a measured temperature T that is equal to the target temperature T. tgt The fan motor 23 corresponding to the object to be cooled is operated in medium output mode, and the measured temperature T is set to the target temperature T. tgt The fan motor 23, which is suitable for cooling objects smaller than a certain size, is operated in low-power mode.

[0046] The changes in measured temperature due to charge / discharge control processing will be explained with reference to Figures 5 and 6. Figure 5 shows the changes in measured temperature when the cooling fan 24A is rotated in low-power mode (i.e., the third power is set to a value greater than 0). Figure 6 shows the changes in measured temperature when the cooling fan 24A is not rotated in low-power mode (i.e., the third power is set to 0). The following explanation will focus on the cooling fan 24A, but the same applies to cooling fans 24B to 24D.

[0047] As shown in Figures 5 and 6, when the brake pedal is released (for example, during acceleration or when stopped) (S11: No), the controller 30 operates the fan motor 23A in medium output mode (S17). As a result, the measured temperature TA detected by the temperature sensor 20a reaches the target temperature TA. tgt It is maintained.

[0048] Next, the controller 30, in response to the brake pedal being pressed (S11: Yes & S12: Yes), uses the regenerative power generated by the drive motors 18L and 18R to operate the fan motor 23A in high-output mode (S14 / S15). As a result, the measured temperature TA detected by the temperature sensor 20a gradually decreases, and the target temperature TA is reached. tgt It falls below that.

[0049] After that, when the brake pedal is released (S11: No), the measured temperature TA becomes the target temperature TA tgt Since it is below the target temperature (S16: No), the controller 30 operates the fan motor 23A in low-power mode (S18). As a result, the measured temperature TA detected by the temperature sensor 20a gradually rises. Then, the controller 30 checks when the measured temperature TA is below the target temperature TA. tgt In response to reaching (S16: Yes), the fan motor 23A is operated in medium output mode (S17).

[0050] Furthermore, while the fan motor 23A is operating in low-power mode, in Figure 5 it is necessary to generate a third power (>0) from the auxiliary generator 14, whereas in Figure 6 the auxiliary generator 14 can be stopped. Therefore, by setting the third power to 0, for example, while the dump truck 1 is being driven, the driving force of the engine 11 can be concentrated and used to drive the travel motors 18L and 18R (i.e., to generate power with the main generator 13).

[0051] On the other hand, during the period when the fan motor 23A is operating in low-power mode, the measured temperature T shown in Figure 5 rises more gradually than the measured temperature T shown in Figure 6. Therefore, by setting the third power to a value greater than 0, the period during which the fan motor 23A operates in low-power mode can be extended. Thus, in this embodiment, the third power may be greater than 0 or 0, as long as it is a value smaller than the first power.

[0052] According to the above embodiment, by using the regenerative power P generated during regeneration to operate the fan motors 23A to 23D in high-output mode, the object to be cooled is supercooled during regeneration (when the measured temperature T reaches the target temperature T). tgt (Below [value]). Therefore, the power generated by the auxiliary generator 14 after the brake pedal is released (=third power) can be made smaller than usual (=first power). As a result, the regenerative energy during braking can be effectively utilized to improve the fuel efficiency of the dump truck 1.

[0053] [Example 1] In the above embodiment, the regenerative power P is equal to the total power P. ALL An example was described in which, if it is determined to be less than (S12: No), all fan motors 23A to 23D are operated in medium output mode. However, the controller 30 may operate some of the higher-priority fan motors 23 in high output mode and the other lower-priority fan motors 23 in medium output mode, within the range of the regenerative power P.

[0054] Figure 7 is a flowchart of the process performed by the controller 30 according to Modification 1, instead of the process enclosed by the dashed line in Figure 4. The process in Figure 7 will be explained below assuming that the cooling priority is fixed in descending order: grid box 20, travel motor 18, generators 13 and 14, and radiator 12.

[0055] First, the controller 30 compares the regenerative power P generated by the drive motors 18L and 18R with the sum of the second power values ​​P(A+B+C+D) of all the fan motors 23A to 23D (S21). Then, if the controller 30 determines that the regenerative power P is equal to or greater than the sum value P(A+B+C+D) (S21: Yes), it operates all the fan motors 23A to 23D in high-output mode (S22).

[0056] Furthermore, if the controller 30 determines that the regenerative power P is less than the total value P(A+B+C+D) (S21: No), it compares the regenerative power P with the sum of the second power of fan motors 23A to 23C and the first power of fan motor 23D, which has the lowest priority, P(A+B+C+d) (S23). Then, if the controller 30 determines that the regenerative power P is equal to or greater than the total value P(A+B+C+d) (S23: Yes), it operates fan motors 23A to 23C in high-output mode and fan motor 23D in medium-output mode (S24).

[0057] Furthermore, if the controller 30 determines that the regenerative power P is less than the total value P(A+B+C+d) (S23: No), it compares the regenerative power P with the sum of the second power of fan motors 23A to 23B and the first power of fan motors 23C to 23D, which have the second lowest priority (S25). Then, if the controller 30 determines that the regenerative power P is equal to or greater than the total value P(A+B+c+d) (S25: Yes), it operates fan motors 23A to 23B in high-output mode and fan motors 23C to 23D in medium-output mode (S26).

[0058] Furthermore, if the controller 30 determines that the regenerated power P is less than the total value P(A+B+c+d) (S25: No), it compares the regenerated power P with the sum of the second power of fan motor 23A and the first power of fan motors 23B to 23D, which have the third lowest priority (S27). Then, if the controller 30 determines that the regenerated power P is equal to or greater than the total value P(A+b+c+d) (S27: Yes), it operates fan motor 23A in high-output mode and fan motors 23B to 23D in medium-output mode (S28).

[0059] On the other hand, if the controller 30 determines that the regenerative power P is less than the total value P(A+b+c+d) (S27:No), it operates all fan motors 23A to 23D in medium output mode (S29). In other words, the controller 30 according to Modification 1, when braking the rear tires 4L and 4R (S11:Yes), supplies predetermined second powers PA, PB, PC, and PD to each fan motor 23A to 23D in order from the fan motor with the highest priority, within the range of the regenerative power P generated by the drive motors 18L and 18R.

[0060] Furthermore, in steps S22, S24, S26, S28, and S29, the controller 30 processes the surplus power P of the regenerated power P. R The energy is consumed by the grid box 20. According to the modified example 1, the regenerative energy during braking can be utilized more effectively, further improving the fuel efficiency of the dump truck 1.

[0061] Note that the priority of fan motors 23A to 23D is not limited to the example described above. Also, the priority may be fixed or it may be changed each time the process shown in Figure 7 is performed. As another example, the controller 30 uses the measured temperatures TA, TB, TC, and TD detected by temperature sensors 20a, 18a, 13a, and 12a, and a predetermined target temperature TA tgt , TB tgt , TC tgt , TD tgtThe priority of the corresponding fan motors 23A to 23D may be set in order of the largest deviation from the measured temperature T to the target temperature T. tgt Prioritize the fan motor 23 corresponding to the object to be cooled, which has a large discrepancy with the measured temperature T and the target temperature T. tgt The priority of the fan motor 23 corresponding to the object to be cooled, which has a small deviation from the above, may be lowered.

[0062] [Differentiation 2] Furthermore, the processes shown in Figures 4 and 7 are not limited to the drive circuit 10 shown in Figure 2. Figure 8 shows a drive circuit 10A according to modified example 2. Components common to the drive circuit 10 shown in Figure 2 are given the same reference numerals, and detailed explanations are omitted; the explanation will focus on the differences.

[0063] As shown in Figure 8, the drive circuit 10A according to the modified example 2 differs from the drive circuit 10 shown in Figure 2 in that it further includes a charge / discharge controller 25 and a storage battery 26. The charge / discharge controller 25 and the storage battery 26 are connected to the travel motors 18L and 18R in parallel with the fan motors 23A to 23D via a step-down device 21.

[0064] The charge / discharge controller 25 controls the charging and discharging of the battery 26 according to the control of the controller 30. More specifically, when the dump truck 1 is powered (for example, during acceleration), the charge / discharge controller 25 outputs (discharges) the power stored in the battery 26 to the inverters 17L, 17R, and 22A~22D. On the other hand, when the dump truck 1 is regenerating (for example, during braking), the charge / discharge controller 25 stores a portion of the regenerative power output from the inverters 17L and 17R in the battery 26.

[0065] Then, in steps S14, S15, S22, S24, S26, S28, and S29, the controller 30 in modified example 2 processes the surplus power P of the regenerated power P. R The regenerative power P is stored in the battery 26 via the charge / discharge controller 25. Furthermore, the controller 30 causes the grid box 20 to consume any remaining regenerative power P after it has been stored in the battery 26.

[0066] According to Modification 2, the fuel efficiency of the dump truck 1 can be further improved by making more effective use of regenerative energy during braking.

[0067] The embodiments described above are illustrative for explaining the present invention and are not intended to limit the scope of the invention to those embodiments only. Those skilled in the art can implement the present invention in various other forms without departing from the spirit of the invention. [Explanation of Symbols]

[0068] 1 Dump truck 2. Vehicle frame 3L, 3R Front Tires 4L, 4R rear tire 5. Cargo bed 6 cabs 6a Operating device 7L, 7R Hoist Cylinder 8 Hinge pins 9 decks 10,10A drive circuit 11 Engine 12. Radiator (object to be cooled) 12a, 13a, 18a, 20a temperature sensors 13. Main generator (objects to be cooled) 14. Auxiliary generator (for cooling objects) 15,16 rectifier 17L, 17R, 22A, 22B, 22C, 22D Inverter 18L, 18R Travel motor (object to be cooled) 19 Choppa 20 Grid boxes (objects to be cooled) 21 Step-down device 23A, 23B, 23C, 23D Fan Motor 24A, 24B, 24C, 24D Cooling Fan 25 Charge / Discharge Controller 26 Storage batteries 30 controllers 31 CPU 32 memory

Claims

1. A vehicle that moves by the rotation of its tires, The engine that generates the driving force, A generator that generates electricity using the driving force of the aforementioned engine, A drive motor that rotates the tires using electricity generated by the generator, The cooling fan rotates upon receiving power, and multiple fan motors cool different objects. A dump truck comprising a controller for controlling the drive of the fan motor, The aforementioned controller, When the tire is not braking, the power generated by the generator is supplied to each of the plurality of fan motors at the magnitude of the first power. When the tires are being braked, if it is determined that the regenerative power generated by the drive motor is less than the sum of the second powers, which are predetermined for each fan motor and are greater than the first power, then the first power from the regenerative power generated by the drive motor is supplied to each of the multiple fan motors. If it is determined that the regenerative power generated by the drive motor is equal to or greater than the sum of the second powers, then the second power from the regenerative power generated by the drive motor is supplied to each of the multiple fan motors. A dump truck characterized by the following features.

2. In the dump truck according to claim 1, The fan motor is equipped with a temperature sensor that detects the temperature of the object being cooled, The aforementioned controller, When the braking of the tire is completed, if the measured temperature detected by the temperature sensor is lower than a predetermined target temperature, the generator is made to generate a third power, which is smaller than the first power, and supplied to the fan motor. A dump truck characterized by the following features.

3. In the dump truck according to claim 1, Equipped with a battery to store electricity, The aforementioned controller, When the tires are being braked, the remaining surplus power from the regenerative power generated by the drive motor, after supplying the second power to the fan motor, is stored in the battery. A dump truck characterized by the following features.

Images