Work vehicle

Abstract

To provide a work vehicle capable of keeping a rise run distance constant even when running performance and working performance change.SOLUTION: A control device of a work vehicle sets a running correction factor and a working correction factor for adjusting a running drive force and a working drive force based on a vehicle speed and an arm angle. The control device calculates a rise run distance based on the vehicle speed and the arm angle, calculates a distance ratio by dividing the rise run distance by a target running distance, and sets a calibration value that increases a suppression amount of the running drive force and a calibration value that decreases a suppression amount of the working drive force as the distance ratio increases. The control device sets a correction value that decreases / increases a suppression amount of the running drive force and a correction value that increases / decreases a suppression amount of the working drive force as an output limit value of a power source decreases. The control device modifies the running correction factor and the working correction factor based on the calibration value and correction value.SELECTED DRAWING: Figure 11

Description

[Technical Field]

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

[0002] Known examples of work vehicles include wheel loaders equipped with a travel device for propelling the vehicle body and a work device for performing excavation work. The work device includes an arm rotatably attached to the vehicle body and a bucket rotatably attached to the arm. When loading soil or sand stored in a bucket into a loading target such as a dump truck, the work vehicle performs an operation called a rise-and-run, in which the arm is raised while the vehicle body moves forward toward the loading target. The rise-and-run requires operation of an arm operating lever, an accelerator pedal, and a brake pedal. Furthermore, the rise-and-run involves quickly moving forward until just before the loading target, and then operating the arm so that it reaches the required height just before the loading target, thereby improving both the efficiency of the transport work and energy efficiency (fuel and electricity consumption). This requires the operator to precisely operate multiple operating components according to the situation, which places a heavy burden on the operator.

[0003] To solve these problems, a work vehicle has been proposed that is equipped with a control device that sets a driving correction factor for adjusting the driving force and a work correction factor for adjusting the work driving force based on the vehicle speed, travel distance, and arm angle calculated based on the detection results of the sensors, as well as a preset target driving distance and target arm angle, and controls the driving force and work driving force based on the set driving correction factor and work correction factor (see Patent Document 1).

[0004] The control device described in Patent Document 1 calculates the remaining time until the target traveling distance is reached as the remaining traveling time based on the vehicle speed, traveling distance, and target traveling distance, and calculates the remaining time until the target arm angle is reached as the remaining work time based on the arm angle and target arm angle. The control device described in Patent Document 1 sets a larger work correction factor to limit the arm lifting speed the shorter the remaining work time is compared to the remaining traveling time, and sets a larger travel correction factor to limit the vehicle speed the longer the remaining work time is compared to the remaining traveling time. This makes it possible to control the rise run distance, which is the traveling distance from the start to the end of the rise run, to a constant value. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-148075 Summary of the Invention [Problem to be solved by the invention]

[0006] In the control method described in Patent Document 1, the characteristics of the control parameters (driving correction factor and work correction factor) are determined according to the driving performance and working performance of a vehicle of a predetermined vehicle class. Therefore, the characteristics of the control parameters cannot be used as is for vehicles of a different vehicle class. For example, when a new product is developed, it is necessary to newly determine the characteristics of the control parameters according to the driving performance and working performance of that product. Furthermore, when vehicle components (e.g., a power source, a motor, a hydraulic pump) are replaced with new components with different specifications, the vehicle class changes, and therefore the characteristics of the control parameters must be newly determined.

[0007] Furthermore, even for vehicles of the same size, when the output of the power source is limited, the driving performance and working performance may change compared to normal operation when the output of the power source is not limited. For this reason, when the output of the power source is limited, there is a risk that the rise run distance may become longer or shorter than the preset target rise run distance.

[0008] An object of the present invention is to provide a work vehicle that is capable of maintaining a constant rise run distance even when the driving performance and working performance change. [Means for solving the problem]

[0009] A work vehicle according to one aspect of the present invention includes wheels attached to a vehicle body, a driving force supply device that supplies driving force to the wheels, a work implement having an arm attached to the vehicle body so as to be rotatable in the vertical direction, a work driving force supply device that supplies work driving force to the work implement, a vehicle speed sensor that detects vehicle speed, an arm relative angle sensor that detects the angle of the arm relative to the vehicle body, a power source that supplies power to the driving force supply device and the work driving force supply device, and a control device that controls at least one of the driving force supply device and the work driving force supply device so that the output of the power source does not exceed an output limit value. The control device sets at least one of a driving correction factor for adjusting the driving force and a work correction factor for adjusting the work driving force based on the vehicle speed detected by the vehicle speed sensor, the arm angle detected by the arm relative angle sensor, a predetermined target traveling distance, and a predetermined target arm angle. When the traveling correction factor is set, the control device controls the traveling driving force of the traveling driving force supply device based on the traveling correction factor, and when the work correction factor is set, the control device controls the work driving force of the work driving force supply device based on the work correction factor. The control device calculates a rise run distance, which is the traveling distance from when the arm starts to rise until it reaches the target arm angle, based on the vehicle speed detected by the vehicle speed sensor and the arm angle detected by the arm relative angle sensor, calculates a distance ratio, which is a value obtained by dividing the calculated rise run distance by the target traveling distance, and sets at least one of a calibration value that increases the amount of suppression of the traveling driving force and a calibration value that decreases the amount of suppression of the work driving force, as the distance ratio increases. In the work vehicle in which the amount of suppression of the traveling driving force becomes larger than the amount of suppression of the work driving force when the output limit value of the power source is reduced, the control device sets at least one of a correction value that decreases the amount of suppression of the traveling driving force and a correction value that increases the amount of suppression of the work driving force, as the output limit value of the power source is reduced.In the work vehicle, where the suppression amount of the driving drive force becomes smaller than the suppression amount of the work drive force when the output limit value of the power source is reduced, the control device sets at least one of a correction value that increases the suppression amount of the driving drive force and a correction value that decreases the suppression amount of the work drive force as the output limit value of the power source is reduced.The control device modifies at least one of the driving correction factor and the work correction factor based on the set calibration value and the set correction value. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a work vehicle that is capable of maintaining a constant rise run distance even when the driving performance and working performance change. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a side view showing a wheel loader 1, which is an example of a work vehicle. [Figure 2] FIG. 2 is a system configuration diagram of the wheel loader 1 according to the first embodiment. [Figure 3] FIG. 3 is a diagram for explaining V-shaped excavation work (V-shape loading) by the wheel loader 1. As shown in FIG. [Figure 4] FIG. 4 is an explanatory diagram for explaining the rise run. [Figure 5] FIG. 5 is a functional block diagram of the control device 100. [Figure 6] FIG. 6 is a diagram showing an example of a correction rate table T0 for calculating the traveling correction rate ηc and the work correction rate ηi. [Figure 7A] FIG. 7A is a diagram showing an example of an output limit value table Tp for setting the output limit value PL. [Figure 7B] FIG. 7B is a diagram showing another example of the output limit value table Tp for setting the output limit value PL. [Figure 8] FIG. 8 is a diagram showing driving performance data Dc representing driving performance and work performance data Di representing work performance. [Figure 9]FIG. 9 is a diagram showing an example of a calibration value table T1 for setting the traveling calibration value Cc1 and the working calibration value Ci1. [Figure 10A] FIG. 10A is a diagram showing an example of a correction value table T2 for setting the driving correction value Cc2 and the work correction value Ci2. [Figure 10B] FIG. 10B is a diagram showing another example of the correction value table T2 for setting the driving correction value Cc2 and the work correction value Ci2. [Figure 11] FIG. 11 is a flowchart showing an example of the procedure of the process executed by the control device 100 when the control mode is set to the normal mode. [Figure 12] FIG. 12 is a flowchart showing an example of the procedure of the process executed by the control device 100 when the control mode is set to the calibration mode. [Figure 13A] FIG. 10 is a diagram showing an example of a correction value table T20 stored in a control device 100 according to a second modification of the first embodiment. [Figure 13B] FIG. 10 is a diagram showing another example of the correction value table T20 stored in the control device 100 according to the second modification of the first embodiment. [Figure 14] FIG. 14 is a system configuration diagram of a wheel loader 1 according to the second embodiment. [Figure 15] FIG. 15 is a system configuration diagram of a wheel loader 1 according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment of a work vehicle according to the present invention will be described below with reference to the drawings. Identical elements are given the same reference numerals, and duplicate explanations will be omitted. While the work vehicle will be described as a wheel loader, the work vehicle of the present invention is not limited to wheel loaders and may be a forklift, lift truck, telehandler, or the like. In the following description, the directions and positions of up / down, left / right, and front / rear are based on the normal use state of the work vehicle, i.e., a state in which the wheels are in contact with level ground.

[0013] First Embodiment FIG. 1 is a side view showing a wheel loader 1, which is an example of a work vehicle. As shown in FIG. 1, the wheel loader 1 of this embodiment is an electrically driven wheel loader that uses a battery 21 as a power source PS0. The wheel loader 1 comprises a body 8 on which a traveling device 14 is mounted, and an articulated working device 6 provided at the front of the body 8. The body 8 is an articulated steering type (body articulating type) body, and has a front body 8A, a rear body 8B, and a center joint 8C that connects the front body 8A and the rear body 8B. The working device 6 is attached to the front body 8A.

[0014] The working device 6 has a pair of left and right arms (also called lift arms) 2 attached to the front vehicle body 8A so as to be rotatable in the vertical direction, an arm cylinder 4 which is a hydraulic cylinder that drives the arms 2, a bucket 3 attached to the arm 2 so as to be rotatable in the vertical direction, and a bucket cylinder 5 which is a hydraulic cylinder that drives the bucket 3. In this embodiment, a Z-link type (bell crank type) link mechanism is used as the link mechanism for operating the bucket 3.

[0015] The rear body 8B is provided with a driver's cab 9 and a power source room 16. The driver's cab 9 is provided with an arm operating device 144 (see FIG. 2) for operating the arm cylinder 4 (arm 2) of the working implement 6, a bucket operating device 145 (see FIG. 2) for operating the bucket cylinder 5 (bucket 3) of the working implement 6, a forward / reverse switching device 143 (see FIG. 2) for switching between forward (F) and reverse (R) travel of the body 8, an accelerator operating device 141 (see FIG. 2) for instructing acceleration of the body 8, a brake operating device 142 (see FIG. 2) for instructing deceleration of the body 8, a steering operating device (not shown) for instructing the left / right traveling direction of the body 8, and a mode switching device 147 for switching the control mode between a normal mode and a calibration mode. The power source room 16 houses a battery 21, which serves as the power source PS0. The power source room 16 also houses hydraulic equipment such as a hydraulic pump 28 (see FIG. 2) and valves.

[0016] Figure 2 is a system configuration diagram of a wheel loader 1 according to the first embodiment. As shown in Figure 2, the wheel loader 1 is equipped with a traveling device 14 that travels the vehicle body 8, a battery 21 that is a power source PS0, a traveling drive force supply device PS1 that receives power (electricity) from the battery 21 and supplies traveling drive force to the wheels 7 of the traveling device 14, a work device 6, a work drive force supply device PS2 that receives power (electricity) from the battery 21 and supplies work drive force to the work device 6, and a control device 100 that controls the power source PS0, traveling drive force supply device PS1, and work drive force supply device PS2.

[0017] The traveling device 14 and the working device 6 are driven independently of each other by power (electricity) from a battery 21. The battery 21 is an electricity storage device having a plurality of power storage elements, and supplies power (electricity) to the traveling driving force supply device PS1 and the work driving force supply device PS2. The power storage elements may be, for example, lithium ion batteries, lead batteries, or electric double layer capacitors.

[0018] The forward / reverse switching device 143 includes a forward / reverse switch that is selectively operated to a forward (F) position, a neutral (N) position, or a reverse (R) position, and an operation position sensor 143a that detects the operation position of the forward / reverse switch. The operation position sensor 143a outputs a forward / reverse signal (FNR signal) corresponding to the selected operation position to the control device 100. The accelerator operation device 141 includes an accelerator pedal and an accelerator operation amount sensor 141a that detects the operation amount of the accelerator pedal (hereinafter also referred to as accelerator operation amount). The accelerator operation amount sensor 141a outputs an accelerator signal indicating the operation amount (depression amount) of the accelerator pedal to the control device 100. The brake operation device 142 includes a brake pedal and a brake operation amount sensor 142a that detects the operation amount of the brake pedal. The brake operation amount sensor 142a outputs a brake signal indicating the operation amount (depression amount) of the brake pedal to the control device 100.

[0019] The arm operating device 144 includes an arm operating lever and an arm operation amount sensor 144a that detects the operation amount of the arm operating lever (hereinafter also referred to as the arm operation amount). The bucket operating device 145 includes a bucket operating lever and a bucket operation amount sensor 145a that detects the operation amount of the bucket operating lever (hereinafter also referred to as the bucket operation amount). The arm operation amount sensor 144a, the bucket operation amount sensor 145a, the accelerator operation amount sensor 141a, and the brake operation amount sensor 142a are, for example, potentiometers that output a voltage corresponding to the operation position of an operating member (operation lever or pedal) to the control device 100. The arm operation amount sensor 144a and the bucket operation amount sensor 145a function as work state detection devices that detect an operation amount that indicates the work state of the working device 6.

[0020] The wheel loader 1 is equipped with a vehicle speed sensor 148 that detects the vehicle speed, which is the traveling speed of the vehicle body 8. The vehicle speed sensor 148 calculates the vehicle speed based on information detected by, for example, a rotary encoder that detects the rotational speed of a shaft that constitutes the power transmission device of the traveling device 14, and outputs the calculation result to the control device 100. The vehicle speed sensor 148 functions as a traveling condition detection device that detects the vehicle speed, which indicates the traveling condition of the traveling device 14.

[0021] The mode switching device 147 has a mode switching switch that can be selectively switched between a normal operation position that sets the control mode to the normal mode and a calibration operation position that sets the control mode to the calibration mode, and an operation position sensor 147a that detects the operation position of the mode switching switch. The operation position sensor 147a outputs a mode setting signal to the control device 100 according to the selected operation position.

[0022] The traveling drive force supply device PS1 has an electric motor (hereinafter also referred to as the traveling motor 11) that is driven by power from the battery 21, and an inverter (hereinafter also referred to as the traveling inverter 22) that controls the torque of the traveling motor 11 based on a traveling drive torque command from the control device 100. The traveling inverter 22 converts DC power from the battery 21 into three-phase AC power to rotate the traveling motor 11. The traveling device 14 has front wheels 7A (wheels 7) attached to the front vehicle body 8A, rear wheels 7B (wheels 7) attached to the rear vehicle body 8B, and a power transmission device that transmits power from the traveling motor 11 to the wheels 7. The wheels 7 rotate when driven by the traveling motor 11, causing the wheel loader 1 to move forward and backward. The power transmission device is configured to include, for example, an axle, a differential device, a propeller shaft, a gear 25, etc. The gear 25 changes the speed of the power of the traveling motor 11 and outputs it. When the travel motor 11 is driven and the power of the travel motor 11 is transmitted to the wheels 7 via the power transmission device, the wheel loader 1 travels.

[0023] The work drive force supply device PS2 has an electric motor (hereinafter also referred to as work motor 12) that is driven by power from the battery 21, a hydraulic pump 28 mechanically connected to the work motor 12, and an inverter (hereinafter also referred to as work inverter 23) that controls the torque of the work motor 12 based on a work drive torque command from the control device 100. The work inverter 23 converts DC power from the battery 21 into three-phase AC power to rotate the work motor 12. The hydraulic pump 28 is rotationally driven by the power of the work motor 12 and discharges hydraulic oil.

[0024] The work device 6 has a control valve unit 29. The pressure, flow rate, and flow direction of the hydraulic oil discharged from the hydraulic pump 28 are controlled by the control valve unit 29. Based on a front control command from the control device 100, the control valve unit 29 adjusts the pressure, speed, and direction of the hydraulic oil discharged from the hydraulic pump 28, and operates the arm cylinder 4 and the bucket cylinder 5.

[0025] The control valve unit 29 includes an arm control valve that controls the flow (flow rate and direction) of hydraulic oil supplied to the arm cylinder 4, a pair of solenoid valves that generate pilot pressure for driving the arm control valve, a bucket control valve that controls the flow (flow rate and direction) of hydraulic oil supplied to the bucket cylinder 5, and a pair of solenoid valves that generate pilot pressure for driving the bucket control valve. The solenoid valve is a pressure reducing valve that reduces the pressure of a pilot hydraulic power source (not shown) and generates pilot pressure in accordance with a control command from the control device 100.

[0026] The control valve unit 29 is controlled based on the operation direction and operation amount of the arm operation device 144 and the bucket operation device 145. By controlling the control valve unit 29, hydraulic oil is supplied to the hydraulic cylinders (arm cylinder 4, bucket cylinder 5) corresponding to the operated operation device (144, 145), and the hydraulic cylinders are driven. The hydraulic cylinders (4, 5) are extended and retracted by hydraulic oil (pressurized oil) discharged from the hydraulic pump 28. When the arm operation device 144 is operated, the arm 2 rotates in the vertical direction in response to the extension and retraction movement of the arm cylinder 4. When the bucket operation device 145 is operated, the bucket 3 rotates in the vertical direction (in the crowding direction and the dumping direction) in response to the extension and retraction movement of the bucket cylinder 5.

[0027] The control device 100 adjusts the traveling driving force, which is the driving force of the traveling device 14, by controlling the traveling inverter 22. In addition, the control device 100 adjusts the work driving force, which is the driving force of the work device 6, by controlling the work inverter 23.

[0028] The control device 100 is composed of a computer equipped with a processing device 101 such as a CPU (Central Processing Unit), MPU (Micro Processing Unit), or DSP (Digital Signal Processor), a non-volatile memory 102 such as a ROM (Read Only Memory), flash memory, or hard disk drive, a volatile memory 103 known as RAM (Random Access Memory), an input / output interface, and other peripheral circuits. These pieces of hardware work together to run software and realize multiple functions. The control device 100 may be composed of one computer or multiple computers.

[0029] The nonvolatile memory 102 stores data tables, thresholds, programs capable of executing various calculations, etc. In other words, the nonvolatile memory 102 is a storage medium (storage device) from which a program for realizing the functions of this embodiment can be read. The volatile memory 103 is a storage medium (storage device) that temporarily stores the results of calculations performed by the processing device 101 and signals input from the input / output interface. The processing device 101 is a device that loads the program stored in the nonvolatile memory 102 into the volatile memory 103 and executes the calculations, and performs predetermined calculations on data taken in from the input / output interface, the nonvolatile memory 102, and the volatile memory 103 in accordance with the program.

[0030] The input section of the input / output interface converts sensor signals input from various sensors into data that can be calculated by the processing device 101 .

[0031] The sensor signals input to control device 100 include a signal representing the accelerator operation amount detected by accelerator operation amount sensor 141a, a signal representing the brake operation amount detected by brake operation amount sensor 142a, a signal representing the arm operation amount detected by arm operation amount sensor 144a, a signal representing the bucket operation amount detected by bucket operation amount sensor 145a, a signal representing the operation position of the forward / reverse switch detected by operation position sensor 143a, and a signal representing the operation position of the mode selector switch detected by operation position sensor 147a.

[0032] The sensor signals input to the control device 100 include a signal representing the angle detected by an arm relative angle sensor 151 provided on the connecting shaft connecting the vehicle body 8 and the arm 2, and a signal representing the angle detected by a bucket relative angle sensor 152 provided on the connecting shaft connecting the arm 2 and the bucket 3. The arm relative angle sensor 151 is a potentiometer that detects the arm angle, which is the angle (relative angle) of the arm 2 with respect to the vehicle body 8, and outputs a signal representing the detection result to the control device 100. The bucket relative angle sensor 152 is a potentiometer that detects the bucket angle, which is the angle (relative angle) of the bucket 3 with respect to the arm 2, and outputs a signal representing the detection result to the control device 100. Because the angle of the vehicle body 8 with respect to the ground (traveling surface) is constant, the angle detected by the arm relative angle sensor 151 corresponds to the angle (relative angle) of the arm 2 with respect to the ground. The arm relative angle sensor 151 and the bucket relative angle sensor 152 function as posture sensors that detect the posture of the working implement 6. The arm relative angle sensor 151 and the bucket relative angle sensor 152 also function as a work state detection device that detects the work state of the work device 6.

[0033] In addition, the sensor signals input to the control device 100 include a signal representing the motor speed detected by a motor speed sensor 146, a signal representing the vehicle speed detected by a vehicle speed sensor 148, a signal representing the pressure of the bucket cylinder 5 detected by a bucket cylinder pressure sensor (pressure sensor) 153, a signal representing the discharge pressure of the hydraulic pump 28 detected by a discharge pressure sensor 154, and a signal representing the current flowing through the traveling motor 11 detected by a current sensor 155.

[0034] The motor speed sensor 146 is, for example, a resolver, which detects the motor speed, which is the rotation speed of the travel motor 11, and outputs a motor speed signal representing the detection result to the control device 100. The motor speed detected by the motor speed sensor 146 has a certain relationship with the vehicle speed. Therefore, the motor speed detected by the motor speed sensor 146 can be converted into the vehicle speed. In other words, the motor speed sensor 146 can also be used as a vehicle speed sensor that detects the vehicle speed.

[0035] The output section of the input / output interface generates an output signal according to the calculation result of the processing device 101, and outputs the signal to the device to be controlled. The device to be controlled includes, for example, the battery 21, the traveling inverter 22, the working inverter 23, the solenoid valve of the control valve unit 29, etc.

[0036] An example of work performed by the wheel loader 1 will be described with reference to FIG. 3. FIG. 3 is a diagram illustrating V-shaped excavation work (V-shape loading) by the wheel loader 1. As shown in FIG. 3, the wheel loader 1 (first operation) moves forward toward a natural ground 91, which is an object to be excavated, and (second operation) plunges the bucket 3 into the natural ground 91 and operates the bucket 3 and the lift arm 2 to perform excavation work of excavating the natural ground 91. After completing the excavation work, the wheel loader 1 (third operation) moves backward to a predetermined position and stops. Thereafter, the wheel loader 1 (fourth operation) moves forward toward a dump truck (object to be loaded) 92 while raising the lift arm 2 (rise run) and stops at a loading position in front of the dump truck 92. Then, (fifth operation) performs loading work, in which the load (excavated material) in the bucket 3 is dumped onto the bed of the dump truck 92. After completing the loading work, the wheel loader 1 (sixth operation) moves backward to a predetermined position. As explained above, the wheel loader 1 repeatedly performs a series of operations from (first operation) to (sixth operation) while tracing a V-shaped trajectory. In this specification, the series of operations from (first operation) to (sixth operation) is also referred to as loader work.

[0037] FIG. 4 is an explanatory diagram illustrating a rise run. As shown in FIG. 4, in a rise run (fourth operation), the operator of the wheel loader 1 operates the arm operating lever to raise the arm 2, while operating the steering wheel (not shown) and accelerator pedal to move the vehicle body 8 (i.e., the wheel loader 1) forward toward the dump truck 92. The operator then operates the brake pedal to stop the vehicle body 8 at a loading position in front of the dump truck 92. In FIG. 3, the wheel loader 1 stopped in front of the dump truck 92 is shown by a dashed line. In the rise run shown in FIG. 4, a series of operations performed by the operator are referred to as "operations associated with the rise run." Furthermore, the travel distance of the wheel loader 1 from the start of travel in the rise run until the arm 2 has fully risen to the height (predetermined height) required for soil discharge (loading) is referred to as the "rise run distance." In other words, the "rise run distance" is the travel distance from when the arm 2 starts to rise until it reaches the target arm angle (the arm angle θmax when the arm 2 has fully risen to the above-mentioned predetermined height) (see FIG. 8).

[0038] The loader operation shown in Figure 3 takes up the majority of the total operating time of the wheel loader 1. Therefore, reducing the operational burden during loader operation is an effective way to reduce the burden on the operator. Here, operational burden refers to the number of times the operator changes the amount of operation of an operating member such as the accelerator pedal or arm operating lever during loader operation. The fewer the number of times the amount of operation of an operating member is changed, the lighter the burden on the operator.

[0039] In loading work, when the operator starts a rise run, he operates the arm control lever to the maximum operation amount (full lever) and the accelerator pedal to the maximum operation amount (full accelerator), and with the lever and accelerator still in the full lever and full accelerator state, the arm angle rises to the height required for discharging (loading) at the loading position in front of the dump truck 92. This results in loading work that places less strain on the operator and has good work efficiency and energy efficiency (electricity cost). Hereinafter, this operation will be referred to as "operation associated with simple rise run."

[0040] However, as described above, when the road surface leading to the dump truck 92 is uphill, performing the operation associated with the simple rise run results in insufficient driving force for traveling, causing the arm 2 to fully rise before the loading position is reached. In other words, the rise run distance is shortened. Similarly, when the bucket height is high at the start of the rise run, the arm 2 will also fully rise before the loading position is reached. In this case, the vehicle body 8 moves forward until the loading position is reached with the operation of the working device 6 completed, so the time spent operating only the traveling device 14 is lengthened, resulting in reduced work efficiency and energy efficiency (electricity cost). To prevent this, the operator must adjust the amount of operation of the arm operating lever during the rise run operation, maintaining a balance between the driving force for traveling and the driving force for working, so that the arm 2 is fully raised at the same time as the loading position is reached. In this case, the burden on the operator increases.

[0041] Furthermore, if the weight of the excavated material in the bucket 3 is greater than the expected weight (rated weight), performing an operation involving simple rise-run will result in insufficient work driving force, and the arm 2 will not fully rise until a predetermined time has elapsed since the loading position was reached. In other words, the rise-run distance will become longer. If the rise-run distance becomes longer, the wheel loader 1 will interfere with the dump truck 92. For this reason, the operator must adjust the accelerator pedal operation amount or operate the brake pedal during the rise-run operation, thereby continually balancing the travel driving force and work driving force so that the arm 2 will fully rise at the same timing as the loading position is reached. In this case, the burden on the operator increases.

[0042] Therefore, the control device 100 according to this embodiment executes "constant rise run distance control" that keeps the rise run distance constant by suppressing one of the traveling drive torque and the work drive torque based on the vehicle speed, which indicates the traveling state of the vehicle body 8, and the arm angle, which indicates the working state of the work implement 6. The constant rise run distance control uses the characteristics of predetermined control parameters. The control parameters include a traveling correction factor for adjusting the traveling drive force (traveling drive torque) and a work correction factor for adjusting the work drive force (work drive torque).

[0043] The characteristics of the control parameters are determined to match the driving performance and working performance of a vehicle of a predetermined vehicle class. Therefore, if the vehicle class of the wheel loader 1 according to this embodiment differs from the predetermined vehicle class, the characteristics of the control parameters cannot be used as is. For this reason, when the control mode is switched from normal mode to calibration mode, the control device 100 according to this embodiment sets a calibration value for modifying the correction factor (control parameter) to perform constant rise-run distance control appropriate for the vehicle class of the wheel loader 1 according to this embodiment, based on the driving state and working state. Note that vehicle class is a general term for various specifications of a wheel loader (work vehicle). The specifications of the wheel loader 1 include, for example, the vehicle size and the output and capacity of components such as the power source PS0 (battery 21 in this embodiment), electric motors (e.g., travel motor 11, work motor 12), and hydraulic pump 28.

[0044] Furthermore, the control device 100 according to this embodiment controls at least one of the traveling driving force supply device PS1 and the working driving force supply device PS2 so that the output of the battery 21 does not exceed the output limit value PL. In an output limited state in which the output of the battery 21 is limited, the balance between the power supplied from the battery 21 to the traveling inverter 22 and the power supplied from the battery 21 to the working inverter 23 differs from that in a normal state in which the output is not limited. For this reason, when the control mode is switched from the calibration mode to the normal mode, the control device 100 according to this embodiment sets a correction value that modifies the correction factor (control parameter) to keep the rise run distance constant when the output of the battery 21 is limited. Below, the rise run distance constant control, calculation of the calibration value, and calculation of the correction value will be described in detail.

[0045] Fig. 5 is a functional block diagram of the control device 100. As shown in Fig. 5, the control device 100 executes programs stored in the nonvolatile memory 102 to function as a remaining driving time calculation unit 111, a remaining work time calculation unit 112, a rise / run determination unit 113, a correction factor setting unit 114, a torque calculation unit 115, a mode setting unit 116, a distance ratio calculation unit 117, a calibration value setting unit 118, a correction value setting unit 119, and a correction value setting unit 120.

[0046] The remaining travel time calculation unit 111 calculates the remaining time until the vehicle body 8 (i.e., the wheel loader 1) reaches the target rise and run distance (target travel distance) as the remaining travel time tc. The remaining travel time calculation unit 111 calculates the remaining travel time tc based on the vehicle speed and target rise and run distance of the wheel loader 1. The remaining travel time tc is calculated, for example, by the following equation (1). tc=(d0-d1) / v1 …(1) In equation (1), d0 is the target rise run distance, d1 is the travel distance at the current time t1 after a predetermined time has elapsed since the rise run start time ts, and v1 is the vehicle speed of the wheel loader 1 at time t1. The rise run start time ts is the time when the rise run flag is switched from off to on by the rise run determination unit 113, which will be described later. The target rise run distance is set in advance based on empirical values ​​and the like, and is stored in the non-volatile memory 102. Note that the operator can also set an arbitrary value for the target rise run distance by operating an input device (not shown). The vehicle speed is detected by the vehicle speed sensor 148. The travel distance is calculated by the remaining travel time calculation unit 111 based on the vehicle speed detected by the vehicle speed sensor 148 and the travel time.

[0047] The remaining work time calculation unit 112 calculates the remaining time until the arm 2 reaches the target arm angle as the remaining work time ti. The remaining work time calculation unit 112 calculates the remaining work time ti based on the arm angle and target arm angular velocity of the wheel loader 1. The remaining work time ti is calculated, for example, by the following equation (2). ti=(θ0-θ1) / ω1 …(2) In equation (2), θ0 is the target arm angle, θ1 is the arm angle at the current time t1 after a predetermined time has elapsed since the rise run start time ts, and ω1 is the arm angular velocity of the wheel loader 1 at time t1. The rise run start time ts is the time when the rise run flag is switched from off to on by the rise run determination unit 113, which will be described later. The target arm angle is set in advance based on the height of the bed of the dump truck 92, and is stored in the non-volatile memory 102. The target arm angle can be changed by the operator operating an input device (not shown). The arm angle is detected by the arm relative angle sensor 151. The arm angular velocity is the time rate of change of the arm angle, and is calculated by the remaining work time calculation unit 112 based on the arm angle detected by the arm relative angle sensor 151.

[0048] The rise run determination unit 113 determines whether the wheel loader 1 is performing a rise run during loading work. That is, the rise run determination unit 113 determines the start and end of a rise run. For example, when the bucket angle φ is equal to or greater than a predetermined transport start angle φ0 and the accelerator operation amount and arm operation amount increase from 0, the rise run determination unit 113 determines that a rise run has started and sets a rise run flag to ON. An increase in the accelerator operation amount from 0 means that the vehicle body 8 has started traveling. An increase in the arm operation amount from 0 means that the arm 2 has started to rise. The transport start angle φ0 is a threshold value used to determine the start of a rise run, and is stored in advance in the non-volatile memory 102. The transport start angle φ0 is set based on the scooping posture of the wheel loader 1. The scooping posture of the working device 6 is a posture in which the top surface of the bucket 3 is approximately parallel to the ground.

[0049] The conditions for determining the start of a rise run are not limited to the above examples. The rise run determination unit 113 may determine that a rise run has started when the time rate of change of the arm angle detected by the arm relative angle sensor 151 changes from a state below a threshold to a state equal to or greater than the threshold, and when the time rate of change of the accelerator operation amount changes from a state below the threshold to a state equal to or greater than the threshold.

[0050] After the start condition of a rise run is met, the rise run determination unit 113 considers that a rise run is being performed and keeps the rise run flag on until the end condition of the rise run is met. When the end condition of a rise run is met, as described below, the rise run determination unit 113 sets the rise run flag off. After the end condition of a rise run is met, the rise run determination unit 113 considers that a rise run is not being performed and keeps the rise run flag off until the start condition of a rise run is met.

[0051] After it is determined that a rise run has started, the rise run determination unit 113 determines that the rise run has ended, for example, when the arm angle θ detected by the arm relative angle sensor 151 becomes equal to or greater than the target arm angle θ0, and sets the rise run flag to OFF. Furthermore, after it is determined that a rise run has started, the rise run determination unit 113 may also determine that the rise run has ended when the accelerator operation amount and the arm operation amount become 0. This makes it possible to prevent the rise run flag from being maintained ON, for example, when the rise run is interrupted.

[0052] The rise run determination unit 113 sets the time when the rise run flag is switched from off to on as the rise run start time (time when arm 2 starts to rise) ts, and sets the time when the rise run flag is switched from on to off as the rise run end time (time when the target arm angle is reached) te.

[0053] When the control mode is set to the normal mode, the correction factor setting unit 114 sets a driving correction factor ηc for adjusting the driving drive torque and a work correction factor ηi for adjusting the work drive torque based on the remaining driving time tc calculated by the remaining driving time calculation unit 111, the remaining work time ti calculated by the remaining work time calculation unit 112, and the rise run flag set by the rise run determination unit 113. The driving correction factor ηc and the work correction factor ηi each take a value between 0 and 1 (0 to 100%).

[0054] Specifically, the correction factor setting unit 114 first calculates the time difference Δt using the following equation (3) based on the remaining driving time tc calculated by the remaining driving time calculation unit 111 and the remaining work time ti calculated by the remaining work time calculation unit 112. Δt=tc-ti …(3) Next, the correction factor setting unit 114 refers to a preset correction factor table T0 and calculates a traveling correction factor ηc and an operation correction factor ηi based on the time difference Δt.

[0055] Fig. 6 is a diagram showing an example of a correction rate table T0 for calculating the driving correction rate ηc and the work correction rate ηi. In Fig. 6, the dashed line indicates the driving correction rate table Tc0 in which the time difference Δt and the driving correction rate ηc are associated with each other, and the solid line indicates the work correction rate table Ti0 in which the time difference Δt and the work correction rate ηi are associated with each other.

[0056] The correction factor table T0 (control parameter characteristics) shown in FIG. 6 was created in advance based on traveling performance data and work performance data obtained from an experiment in which a wheel loader of a predetermined vehicle class was used to perform operations associated with a simple rise run, and the table is stored in the non-volatile memory 102 of the control device 100. In the experiment, the weight of the load (excavated material) loaded on the bucket 3 was the rated weight, and the traveling surface was horizontal. As shown in FIG. 6, the traveling correction factor table Tc0 defines a characteristic in which the traveling correction factor ηc is 0% in range B where the time difference Δt is 0 or more, and in range A where the time difference Δt is 0 or less, the smaller the time difference Δt is (the larger the negative direction), the greater the traveling correction factor ηc becomes. The work correction factor table Ti0 defines a characteristic in which the time difference Δt is 0% in range A where the time difference Δt is 0 or less, and the larger the work correction factor ηi becomes in range B where the time difference Δt is 0 or more, the greater the time difference Δt becomes.

[0057] The correction factor η defined by the correction factor table T0 is a control parameter that performs correction so as to increase the amount of torque suppression; the larger the correction factor η, the greater the amount of torque suppression. For this reason, when an operation involving a simple rise run is performed during loading work with the wheel loader 1, the shorter the remaining work time ti is compared to the remaining travel time tc (the larger the time difference Δt), the larger the work correction factor ηi, so the work drive torque (work drive force) can be reduced more quickly. As a result, the lifting speed of the arm 2 is significantly restricted. On the other hand, the longer the remaining work time ti is compared to the remaining travel time tc (the smaller the time difference Δt), the larger the travel correction factor ηc, so the travel drive torque (travel drive force) can be reduced more quickly. As a result, the vehicle speed of the wheel loader 1 is significantly restricted.

[0058] Because the correction factor table T0 is determined based on the traveling performance data and working performance data (see FIG. 8) of a wheel loader of a predetermined vehicle class, it cannot be used as is for wheel loaders 1 of a different vehicle class. Furthermore, as will be described later, if the output of the battery 21 is limited and the balance between the traveling driving force and the working driving force becomes different from normal, using the correction factor table T0 as is will result in a decrease in the accuracy of the rise run distance constant control.

[0059] For this reason, the correction factor setting unit 114 according to this embodiment corrects the correction factors η (driving correction factor ηc and work correction factor ηi) using the correction value C0 (driving correction value Cc0 and work correction value Ci0) set by the correction value setting unit 120. The corrected driving correction factor is referred to as a corrected driving correction factor ηcr, and the corrected work correction factor is referred to as a corrected work correction factor ηir. The correction value C0 is set based on a calibration value C1 (driving calibration value Cc1 and work calibration value Ci1) that is set in consideration of differences in vehicle class, and a correction value C2 (driving correction value Cc2 and work correction value Ci2) that is set in consideration of changes in the output limit value of the battery 21 during vehicle operation. Details of the calibration value C1, correction value C2, and correction value C0 will be described later.

[0060] The torque calculation unit 115 calculates a traveling drive torque command value for controlling the traveling drive torque and a work drive torque command value for controlling the work drive torque, based on the corrected traveling correction rate ηcr and corrected work correction rate ηir set by the correction rate setting unit 114, as well as the traveling torque requirement Tcr and work torque requirement Tir. The torque calculation unit 115 outputs a traveling drive torque command (control signal) corresponding to the calculated traveling drive torque command value to the traveling inverter 22. The torque calculation unit 115 outputs a work drive torque command (control signal) corresponding to the calculated work drive torque command value to the work inverter 23.

[0061] The torque calculation unit 115 calculates the running target torque Tct based on the running torque requirement Tcr and the modified running correction rate ηcr set by the correction rate setting unit 114. The running target torque Tct is calculated, for example, by the following equation (4). Tct = Tcr × (1 - ηcr) … (4) The required traveling torque Tcr is calculated by the control device 100 based on, for example, the rotation speed of the traveling motor 11, the accelerator operation amount, and the gear ratio. Since the method of calculating the required traveling torque Tcr is well known, a detailed explanation will be omitted. Note that the required traveling torque Tcr increases as the accelerator operation amount increases. Also, the required traveling torque Tcr increases as the rotation speed of the traveling motor 11 decreases.

[0062] Furthermore, the torque calculation unit 115 calculates the task target torque Tit based on the task required torque Tir and the modified task correction rate ηir set by the correction rate setting unit 114. The task target torque Tit is calculated, for example, by the following equation (5). Tit = Tir × (1 - ηir) … (5) The work required torque Tir is calculated by the control device 100 based on, for example, the amount of arm operation and the amount of bucket operation. Since the method of calculating the work required torque Tir is well known, a detailed description will be omitted. The work required torque Tir increases as the amount of arm operation increases. Furthermore, the work required torque Tir increases as the amount of bucket operation increases.

[0063] When the sum of the traveling target driving force proportional to the traveling target torque Tct and the work target driving force proportional to the work target torque Tit is equal to or less than the output limit value PL, which is the upper limit of the power (electricity) of the battery 21, the torque calculation unit 115 determines the traveling target torque Tct as the traveling driving torque command value and determines the work target torque Tit as the work driving torque command value. As described above, the traveling target torque Tct is expressed by equation (4), and the work target torque Tit is expressed by equation (5). In other words, the larger the corrected traveling correction rate ηcr, the greater the amount of suppression of the traveling driving force (traveling driving torque), and the smaller the traveling driving force. Furthermore, the larger the corrected work correction rate ηir, the greater the amount of suppression of the work driving force (work driving torque), and the smaller the work driving force.

[0064] On the other hand, when the total driving force, which is the sum of the traveling target driving force and the work target driving force, is greater than the output limit value of the battery 21, the torque calculation unit 115 determines the traveling driving torque command value and the work driving torque command value so that the total driving force does not exceed the power (electric power) of the battery 21. The determination method may limit only the traveling driving torque command value to be small relative to the traveling target torque Tct, or only the work driving torque command value to be small relative to the work target torque Tit, or may limit both the traveling driving torque command value and the work driving torque command value to be small relative to the target torque. Note that when both the traveling driving torque command value and the work driving torque command value are limited, the limit amounts may be different. As will be described later, in this embodiment, even when the balance between the suppression amount of the traveling driving force and the suppression amount of the work driving force is different, the rise run distance can be kept constant because the correction rate table T0 is corrected using the correction value C2.

[0065] The control device 100 monitors the state of charge (SOC) of the battery 21, and performs output limit control of the battery 21 when the state of charge SOC of the battery 21 becomes a low charge state below a predetermined value Sth. The control device 100 references a predetermined output limit value table Tp and sets an output limit value PL of the battery 21 based on the state of charge SOC of the battery 21. The control device 100 executes output limit control of the battery 21 based on the set output limit value PL. In the output limit control, the control device 100 controls one of the voltage and the current to limit the power output from the battery 21.

[0066] 7A is a diagram showing an example of an output limit value table Tp for setting the output limit value PL. The output limit value table Tp shown in FIG. 7A is created in advance based on experimental data, etc., and is stored in the non-volatile memory 102 of the control device 100. As shown in FIG. 7A, the output limit value table defines a characteristic in which the output limit value PL decreases as the state of charge SOC decreases in a range in which the state of charge SOC is less than a predetermined value Sth. Note that the output limit value table Tp defines a characteristic in which the output limit value PL becomes a maximum value Pmax in a range in which the state of charge SOC is equal to or greater than the predetermined value Sth. The maximum value Pmax corresponds to the maximum power that can be supplied from the battery 21.

[0067] The output limit value table Tp is not limited to the example shown in Fig. 7A. Fig. 7B is a diagram showing another example of the output limit value table Tp for setting the output limit value PL. The output limit value table Tp shown in Fig. 7B defines a characteristic in which the output limit value PL decreases as the state of charge SOC decreases over the entire range of the state of charge SOC from 0% to 100%. When the state of charge SOC is 100%, the output limit value PL becomes a maximum value Pmax.

[0068] 5 sets the control mode in response to the operation of the mode switching device 147. When the mode setting signal output from the operation position sensor 147a is a signal for setting the normal mode, the mode setting unit 116 sets the control mode to the normal mode. When the mode setting signal output from the operation position sensor 147a is a signal for setting the calibration mode, the mode setting unit 116 sets the control mode to the calibration mode.

[0069] When the mode setting unit 116 sets the control mode to the calibration mode, the correction factor setting unit 114 sets the corrected traveling correction factor ηcr to 0. As a result, the torque calculation unit 115 does not correct the traveling demand torque Tcr, and the traveling demand torque Tcr becomes the traveling target torque Tct as it is (Tct = Tcr). Similarly, when the mode setting unit 116 sets the control mode to the calibration mode, the correction factor setting unit 114 sets the corrected work correction factor ηir to 0. As a result, the torque calculation unit 115 does not correct the work demand torque Tir, and the work demand torque Tir becomes the work target torque Tit as it is (Tit = Tir). In other words, when the mode setting unit 116 sets the control mode to the calibration mode, the rise run distance constant control becomes invalid.

[0070] When the control mode is set to the calibration mode by the mode setting unit 116, the distance ratio calculation unit 117 calculates a rise run distance L1, which is the distance traveled from when the arm 2 starts to rise until it reaches the target arm angle, based on the vehicle speed detected by the vehicle speed sensor 148 and the determination result of the rise run determination unit 113. In this embodiment, the distance ratio calculation unit 117 calculates the rise run distance L1, which is the distance traveled from the rise run start time ts to the rise run end time te, based on time series data of the vehicle speed from the rise run start time ts to the rise run end time te.

[0071] FIG. 8 is a diagram showing driving performance data Dc representing driving performance and work performance data Di representing work performance. The horizontal axis in FIG. 8 represents time. The vertical axis in FIG. 8(a) represents traveled distance (corresponding to the time integral of vehicle speed), and the vertical axis in FIG. 8(b) represents arm angle. As shown in FIG. 8, the distance ratio calculation unit 117 calculates the traveled distance (travel data) per unit time from the rise run start time ts to the rise run end time te, and accumulates the calculation results to obtain the driving performance data Dc. Note that the distance ratio calculation unit 117 may also obtain the work performance data Di by recording the arm angle θ (work data) detected by the arm relative angle sensor 151 for each unit time from the rise run start time ts to the rise run end time te.

[0072] 8, rise run distance L1 is the distance traveled by vehicle body 8 from rise run start time ts to rise run end time te. The time from rise run start time ts to rise run end time te is also referred to as rise run time. Distance ratio calculation unit 117 calculates distance ratio R, which is the value obtained by dividing the calculated rise run distance L1 by a predetermined target rise run distance d0 (R=L1 / d0).

[0073] The calibration value setting unit 118 shown in FIG. 5 refers to a preset calibration value table T1 and sets a traveling calibration value Cc1 and an operation calibration value Ci1 based on the distance ratio R calculated by the distance ratio calculation unit 117. FIG. 9 is a diagram showing an example of the calibration value table T1 for setting the traveling calibration value Cc1 and the operation calibration value Ci1. In FIG. 9, the solid line indicates the traveling calibration value table Tc1 in which the distance ratio R and the traveling calibration value Cc1 are associated with each other, and the dashed line indicates the operation calibration value table Ti1 in which the distance ratio R and the operation calibration value Ci1 are associated with each other. The traveling calibration value Cc1 and the operation calibration value Ci1 are values ​​equal to or greater than 0. As will be described later, the correction factors η (traveling correction factor ηc and operation correction factor ηi) are corrected by multiplying them by the calibration values ​​(traveling calibration value Cc1 and operation calibration value Ci1). In FIG. 9, the distance ratio R and the calibration value C1 have a linear relationship, but the relationship does not have to be linear as long as the relationship is a monotonically increasing or decreasing relationship.

[0074] The calibration value table T1 shown in FIG. 9 is created in advance based on experimental data, etc., and is stored in the non-volatile memory 102 of the control device 100. As shown in FIG. 9, the traveling calibration value table Tc1 defines a characteristic in which the traveling calibration value Cc1 increases as the distance ratio R increases. The larger the traveling calibration value Cc1, the greater the amount of suppression of the traveling drive force. The work calibration value table Ti1 defines a characteristic in which the work calibration value Ci1 decreases as the distance ratio R increases. The smaller the work calibration value Ci1, the less the amount of suppression of the work drive force.

[0075] A small distance ratio R means that if the traveling drive torque is suppressed too much, the actual rise run distance will be shorter than the target rise run distance. For this reason, the smaller the distance ratio R, the smaller the traveling calibration value Cc1. On the other hand, slowing down the movement of the arm 2 is effective in bringing the actual rise run distance closer to the target rise run distance. For this reason, the smaller the distance ratio R, the larger the work calibration value Ci1. This makes it possible to extend the rise run time and increase the traveling distance.

[0076] The reference distance ratio Rb is the distance ratio R at which the traveling calibration value Cc1 and the work calibration value Ci1 become 1.0. The reference distance ratio Rb is the ratio between the actual traveling distance (reference rise run distance) when an experiment was conducted to determine the correction rate table T0, that is, when a wheel loader of a predetermined vehicle class performed a rise run with constant rise run distance control disabled, and the target rise run distance (reference target rise run distance) when a vehicle of the above-mentioned predetermined vehicle class was used.

[0077] Therefore, when the distance ratio R is greater than a predetermined reference distance ratio Rb, a travel calibration value Cc1 is set that increases the amount of suppression of the travelling drive force and a work calibration value Ci1 is set that decreases the amount of suppression of the work drive force, compared to when rise run constant distance control is executed without modifying the correction rate η using the calibration value C1. (Cc1>1.0, Ci1<1.0) Also, when the distance ratio R is less than the reference distance ratio Rb, a travel calibration value Cc1 is set that decreases the amount of suppression of the travelling drive force and a work calibration value Ci1 is set that increases the amount of suppression of the work drive force, compared to when rise run constant distance control is executed without modifying the correction rate η using the calibration value C1. (Cc1<1.0, Ci1>1.0)

[0078] It should be noted that if a rise run is performed using the wheel loader 1 according to this embodiment, which is the same size as the wheel loader from which the control parameter characteristics (correction rate table T0) were obtained, and under conditions equivalent to the experimental conditions when the control parameter characteristics were obtained (for example, the weight of the load in the bucket 3 is the same), then theoretically the traveling calibration value Cc1 and the work calibration value Ci1 will be 1.0, and no calibration (modification) of the control parameter characteristics (correction rate table T0) will actually be performed.

[0079] The correction value setting unit 119 shown in FIG. 5 references a preset correction value table T2 and sets a driving correction value Cc2 and an work correction value Ci2 based on the output limit value PL of the battery 21. FIG. 10A is a diagram showing an example of the correction value table T2 for setting the driving correction value Cc2 and the work correction value Ci2. FIG. 10B is a diagram showing another example of the correction value table T2 for setting the driving correction value Cc2 and the work correction value Ci2. In FIGS. 10A and 10B, the solid lines indicate the driving correction value table Tc2 in which the output limit value PL and the driving correction value Cc2 are associated, and the dashed lines indicate the work correction value table Ti2 in which the output limit value PL and the work correction value Ci2 are associated. The driving correction value Cc2 and the work correction value Ci2 are values ​​greater than or equal to 0. As will be described later, the correction factors η (driving correction factor ηc and work correction factor ηi) are corrected by multiplying them by the correction values ​​(driving correction value Cc2 and work correction value Ci2).

[0080] The correction value table T2 shown in FIGS. 10A and 10B is created in advance based on experimental data, etc., and stored in the non-volatile memory 102 of the control device 100. When the amount of suppression of the driving force from the normal state is greater than the amount of suppression of the work driving force in an output-limited state in which the output of the battery 21 is limited, it is assumed that the rise run distance in the output-limited state will be shorter than the target rise run distance. In this case, the correction value table T2 shown in FIG. 10A is stored in the non-volatile memory 102. As shown in FIG. 10A, the driving correction value table Tc2 defines a characteristic such that, when the output limit value PL is less than the threshold value Pth, the driving correction value Cc2 decreases as the output limit value PL decreases. As the driving correction value Cc2 decreases, the amount of suppression of the driving drive force decreases. The work correction value table Ti2 defines a characteristic such that, when the output limit value PL is less than the threshold value Pth, the work correction value Ci2 increases as the output limit value PL decreases. As the work correction value Ci2 increases, the amount of suppression of the driving drive force increases.

[0081] The traveling correction value table Tc2 and the work correction value table Ti2 specify characteristics such that the traveling correction value Cc2 and the work correction value Ci2 are 1.0 when the output limit value PL is equal to or greater than the threshold value Pth and equal to or less than the maximum value Pmax. In other words, when the output limit value PL is equal to or greater than the threshold value Pth, the correction rate η is not substantially modified by the correction value C2. This is because, in this embodiment, even if the output limit value PL decreases due to a decrease in the state of charge SOC, the output is not limited to a level that restricts the traveling drive torque and work drive torque of the wheel loader 1. When the traveling drive torque and work drive torque are immediately restricted when the output limit value PL decreases from the maximum value Pmax, the correction value table T2 has characteristics such that the correction value changes when the output limit value PL is less than the maximum value Pmax.

[0082] Thus, in the wheel loader 1 in which the suppression amount of the traveling drive force becomes greater than the suppression amount of the work drive force when the output limit value PL of the battery 21 decreases, the control device 100 according to this embodiment sets a traveling correction value Cc2 that decreases the suppression amount of the traveling drive force and a work correction value Ci2 that increases the suppression amount of the work drive force as the output limit value PL of the battery 21 decreases. As a result, even in a state in which the output limit value PL of the battery 21 has decreased, the rise run time is extended and a decrease in vehicle speed is suppressed, so that the actual rise run distance can be made to approach the target rise run distance.

[0083] On the other hand, when the amount of suppression of the traveling drive force is smaller than the amount of suppression of the work drive force in an output limited state in which the output of the battery 21 is limited, it is expected that the rise run distance in the output limited state will be longer than the target rise run distance. In this case, a correction value table T2 such as that shown in FIG. 10B is stored in the non-volatile memory 102. As shown in FIG. 10B, the traveling correction value table Tc2 defines a characteristic in which, when the output limit value PL is less than the threshold value Pth, the traveling correction value Cc2 increases as the output limit value PL decreases. The larger the traveling correction value Cc2, the greater the amount of suppression of the traveling drive force. The work correction value table Ti2 defines a characteristic in which, when the output limit value PL is less than the threshold value Pth, the work correction value Ci2 decreases as the output limit value PL decreases. The smaller the work correction value Ci2, the less the amount of suppression of the work drive force. The driving correction value table Tc2 and the work correction value table Ti2 define characteristics such that the driving correction value Cc2 and the work correction value Ci2 are 1.0 when the output limit value PL is in the range of not less than the threshold value Pth and not more than the maximum value Pmax.

[0084] Thus, in the wheel loader 1 in which the suppression amount of the traveling drive force when the output limit value PL of the battery 21 decreases is smaller than the suppression amount of the work drive force, the control device 100 according to this embodiment sets a traveling correction value Cc2 that increases the suppression amount of the traveling drive force and a work correction value Ci2 that decreases the suppression amount of the work drive force as the output limit value PL of the battery 21 decreases. As a result, even in a state in which the output limit value PL of the battery 21 has decreased, the actual rise run distance can be made to approach the target rise run distance by sufficiently slowing down the vehicle speed and suppressing a decrease in the arm raising speed.

[0085] The correction value setting unit 120 shown in FIG. 5 sets the correction value C0 (driving correction value Cc0 and work correction value Ci0) based on the calibration value C1 (driving calibration value Cc1 and work calibration value Ci1) set by the calibration value setting unit 118 and the correction value C2 (driving correction value Cc2 and work correction value Ci2) set by the correction value setting unit 119. The correction value setting unit 120 according to this embodiment calculates and stores the value obtained by multiplying the driving calibration value Cc1 and the driving correction value Cc2 as the driving correction value Cc0. The correction value setting unit 120 also calculates and stores the value obtained by multiplying the work calibration value Ci1 and the work correction value Ci2 as the work correction value Ci0. In this way, the correction value setting unit 120 sets the correction value C0 by integrating the calibration value C1 and the correction value C2.

[0086] The correction factor setting unit 114 calculates and stores a value obtained by multiplying the driving correction value Cc0 by the pre-correction driving correction factor ηc as a corrected driving correction factor ηcr. The correction factor setting unit 114 also calculates and stores a value obtained by multiplying the work correction value Ci0 by the pre-correction work correction factor ηi as a corrected work correction factor ηir.

[0087] Once the calibration value C1 is set, it does not need to be reset until the vehicle class is changed, for example, when equipment that affects driving performance or work performance is replaced with equipment of different specifications. Therefore, the calibration value C1 can also be considered an initial correction value for correcting the correction factor η. On the other hand, the correction value C2 is used to correct the correction factor η only when the battery 21 transitions to a low charge state during vehicle operation. Therefore, the correction value C2 can also be considered a transient correction value for correcting the correction factor η.

[0088] An example of the processing procedure of the control device 100 will be described with reference to Fig. 11 and Fig. 12. Fig. 11 is a flowchart showing an example of the processing procedure executed by the control device 100 when the control mode is set to the normal mode. Fig. 12 is a flowchart showing an example of the processing procedure executed by the control device 100 when the control mode is set to the calibration mode. When the ignition switch of the wheel loader 1 is turned on, the control device 100 repeatedly executes processing at a predetermined control period to determine whether the control mode is set to the normal mode or the calibration mode. The processing of the flowchart shown in Fig. 11 is started when the control mode is set to the normal mode, and is repeatedly executed at a predetermined control period. The processing of the flowchart shown in Fig. 12 is started when the control mode is set to the calibration mode, and is repeatedly executed at a predetermined control period.

[0089] 11, in step S110, the control device 100 determines whether the rise run flag is set to on. If it is determined that the rise run flag is set to on, the process proceeds to step S113, and if it is determined that the rise run flag is set to off, the process proceeds to step S126.

[0090] In step S113, the control device 100 calculates the remaining travel time tc based on the distance traveled by the wheel loader 1 from the rise run start time ts to the current time t1 (traveling distance d1), the vehicle speed v1 of the wheel loader 1 at the current time t1, and a predetermined target rise run distance d0 (see equation (1)). The control device 100 also calculates the remaining work time ti based on the arm angle θ1 of the wheel loader 1 at the current time t1, a predetermined target arm angle θ0, and the arm angular velocity ω1 at the current time t1 (see equation (2)). The control device 100 calculates a time difference Δt based on the calculated remaining travel time tc and remaining work time ti (see equation (3)).

[0091] In the next step S116, the control device 100 calculates the correction rate η (the driving correction rate ηc and the work correction rate ηi) based on the predetermined correction rate table T0 (the driving correction rate table Tc0 and the work correction rate table Ti0 shown in FIG. 6) and the time difference Δt calculated in step S113.

[0092] In the next step S119, the control device 100 calculates the correction value C2 (driving correction value Cc2 and work correction value Ci2) based on the predetermined correction value table T2 (driving correction value table Tc2 and work correction value table Ti2 shown in Figure 10A or 10B) and the output limit value PL.

[0093] In the next step S121, the control device 100 calculates the correction value C0 (traveling correction value Cc0 and work correction value Ci0) based on the correction value C2 (traveling correction value Cc2 and work correction value Ci2) calculated in step S119 and the calibration value C1 (traveling calibration value Cc1 and work calibration value Ci1) stored in the nonvolatile memory 102. The calibration value C1 is calculated in the processing of step S151 (see FIG. 12) described later and stored in the nonvolatile memory 102.

[0094] In the next step S123, the control device 100 corrects the correction factors η (driving correction factor ηc and work correction factor ηi) using the correction values ​​C0 (driving correction factor Cc0 and work correction factor Ci0) calculated in step S121. In other words, the control device 100 calculates the corrected correction factors ηr (corrected driving correction factor ηcr and corrected work correction factor ηir) based on the correction factors η and the correction values ​​C0.

[0095] In step S126, the control device 100 sets the modified correction rate ηr (modified traveling correction rate ηcr and modified work correction rate ηir) to 0. That is, the process of step S126 corresponds to the process of disabling the rise run distance constant control.

[0096] Once the modified correction rate ηr is set in step S123 or step S126, the process proceeds to step S128. In step S128, the control device 100 calculates the traveling target torque Tct based on the modified traveling correction rate ηcr calculated in step S123 or step S126 and the traveling required torque Tcr (see equation (4)). The control device 100 also calculates the working target torque Tit based on the modified work correction rate ηir calculated in step S123 or step S126 and the work required torque Tir (see equation (5)).

[0097] In step S128, the control device 100 calculates a traveling drive torque command value and a work drive torque command value based on the traveling target torque Tct, the work target torque Tit, and the output limit value PL. As a result, a traveling drive torque command (control signal) based on the traveling drive torque command is output from the control device 100 to the traveling inverter 22, and a work drive torque command (control signal) based on the work drive torque command value is output from the control device 100 to the work inverter 23.

[0098] If the processing of step S128 is executed after the processing of step S126, the traveling torque requirement Tcr becomes the traveling target torque Tct as is, and the working torque requirement Tir becomes the working target torque Tit as is. When the processing of step S128 ends, the processing of the flowchart in Fig. 11 for this control cycle ends, and the processing of step S110 starts again in the next control cycle.

[0099] As shown in FIG. 12, in step S130, the control device 100 executes processing to set the modified correction rate ηr to 0, similar to step S119 (see FIG. 11). In the next step S133, similar to step S110 (see FIG. 11), the control device 100 determines whether the rise run flag is set to on. If it is determined that the rise run flag is set to on, the processing proceeds to step S136, and if it is determined that the rise run flag is set to off, the processing proceeds to step S154. The processing of steps S136 and S154 is the same as the processing of step S128 (see FIG. 11), and therefore description thereof will be omitted. By the processing of step S130, the rise run distance constant control is disabled in the calibration mode.

[0100] When the process of step S136 ends, the process proceeds to step S139. In step S139, the control device 100 calculates, for example, the travel distance traveled in one control cycle as travel data, and stores the calculated data.

[0101] In the next step S142, the control device 100 determines whether the rise run flag is set to OFF. If it is determined that the rise run flag is set to OFF, the process proceeds to step S145, and if it is determined that the rise run flag is set to ON, the process returns to step S136.

[0102] In step S145, the control device 100 calculates a rise run distance L1 based on the travel data accumulated from when the rise run flag was set to on until when it was set to off. In the next step S148, the control device 100 calculates a distance ratio R (R=L1 / d0) by dividing the rise run distance L1 calculated in step S145 by a predetermined target rise run distance d0.

[0103] In the next step S151, the control device 100 refers to a predetermined calibration value table T1, calculates the calibration value C1 (the driving calibration value Cc1 and the working calibration value Ci1) based on the distance ratio R calculated in step S148, and stores it in the non-volatile memory 102.

[0104] When the processing of step S151 or step S154 is completed, the processing of the flowchart in Fig. 12 for this control cycle is completed, and the processing of step S130 is started again in the next control cycle. When the control mode is switched from the calibration mode to the normal mode by the mode switching device 147, the processing of the flowchart in Fig. 12 is completed, and the processing of the flowchart in Fig. 11 is executed. Note that when the processing of step S151 is completed, the control mode may be automatically returned to the normal mode.

[0105] According to the above-described embodiment, the following advantageous effects are achieved.

[0106] (1) When the control mode is set to normal mode, the control device 100 sets a traveling correction factor ηc for adjusting the traveling drive force and a work correction factor ηi for adjusting the work drive force based on the vehicle speed detected by the vehicle speed sensor 148, the arm angle θ detected by the arm relative angle sensor 151, a predetermined target rise / run distance (target traveling distance) d0, and a predetermined target arm angle θ0. The control device 100 controls the traveling drive force of the traveling drive force supply device PS1 based on the set traveling correction factor ηc. The control device 100 controls the work drive force of the work drive force supply device PS2 based on the set work correction factor ηi.

[0107] The wheel loader 1 is equipped with a mode switching device 147 that switches the control mode from normal mode to calibration mode. When the control mode is switched from normal mode to calibration mode, the control device 100 calculates a rise-run distance L1, which is the distance traveled from when the arm 2 starts to rise until it reaches the target arm angle θ0, based on the vehicle speed detected by the vehicle speed sensor 148 and the arm angle θ detected by the arm relative angle sensor 151 (see S130, S133, S136, S139, S142, and S145 in FIG. 12). The control device 100 calculates a distance ratio R, which is the value obtained by dividing the calculated rise-run distance L1 by the target rise-run distance d0 (see S148 in FIG. 12). The control device 100 sets a travel calibration value Cc1, which is a calibration value C1 that increases the amount of suppression of the travel driving force, and a work calibration value Ci1, which is a calibration value C1 that decreases the amount of suppression of the work driving force, as the distance ratio R increases (see S151 in Figure 12).

[0108] When the control mode is switched from calibration mode to normal mode, in a wheel loader (work vehicle) 1 in which the amount of suppression of the traveling drive force when the output limit value PL of the battery (power source) 21 decreases is greater than the amount of suppression of the work drive force, the control device 100 sets a traveling correction value Cc2, which is a correction value C2 that reduces the amount of suppression of the traveling drive force, and a work correction value Ci2, which is a correction value C2 that increases the amount of suppression of the work drive force, as the output limit value PL of the battery 21 decreases.

[0109] When the control mode is switched from the calibration mode to the normal mode, in the wheel loader 1, where the amount of suppression of the traveling drive force when the output limit value PL of the battery 21 decreases is smaller than the amount of suppression of the work drive force, the control device 100 sets a traveling correction value Cc2, which is a correction value C2 that increases the amount of suppression of the traveling drive force, and a work correction value Ci2, which is a correction value C2 that decreases the amount of suppression of the work drive force, as the output limit value PL of the battery 21 decreases.

[0110] The control device 100 corrects the traveling correction factor ηc and the work correction factor ηi based on the set calibration value C1 and the set correction value C2. That is, the control device 100 calculates the corrected correction factor ηr (the corrected traveling correction factor ηcr and the corrected work correction factor ηir) based on the calibration value C1, the correction value C2, and the correction factor η. The control device 100 controls the traveling driving force supply device PS1 and the work driving force supply device PS2 based on the corrected correction factor ηr.

[0111] As described above, according to this embodiment, in a wheel loader 1 that uses the battery 21 as the power source PS0, the rise run distance can be kept constant regardless of the vehicle class and the output limit value PL of the battery 21. In other words, it is possible to provide a wheel loader 1 that is able to keep the rise run distance constant even when the traveling performance and working performance change due to a change in vehicle class or a change in the output limit value PL of the power source PS0. According to this embodiment, it is possible to improve the robustness of the rise run distance constant control and to improve working efficiency. Note that by separately calculating the calibration value C1 that takes into account changes in vehicle class and the correction value C2 that takes into account changes in the output limit value PL of the power source PS0, the correction rate η can be adjusted to an optimal value.

[0112] (2) When the distance ratio R is greater than a predetermined reference distance ratio Rb, the control device 100 sets a travel calibration value Cc1 that increases the amount of suppression of the travel driving force and a work calibration value Ci1 that decreases the amount of suppression of the work driving force, compared to when the travel correction rate ηc and the work correction rate ηi are not corrected using the calibration value C1 (i.e., when the calibration value C1 is 1) (see FIG. 9). Furthermore, when the distance ratio R is smaller than the reference distance ratio Rb, the control device 100 sets a travel calibration value Cc1 that decreases the amount of suppression of the travel driving force and a work calibration value Ci1 that increases the amount of suppression of the work driving force, compared to when the travel correction rate ηc and the work correction rate ηi are not corrected using the calibration value C1 (i.e., when the calibration value C1 is 1).

[0113] The reference distance ratio Rb is the ratio between the rise run distance (reference rise run distance) Lb1 in a state in which constant rise run distance control is disabled in a wheel loader 1 of a predetermined vehicle class used when determining the correction rate table T0, and the target rise run distance (reference target rise run distance) db0 for the wheel loader 1 of a predetermined vehicle class (Rb=Lb1 / db0). This makes it possible to execute constant rise run distance control with greater precision.

[0114] <Modification 1 of the First Embodiment> In the above embodiment, an example has been described in which the correction value C2 is set based on the output limit value PL, but the method of setting the correction value C2 is not limited to this. The control device 100 may also calculate the correction value C2 based on the state of charge SOC, which has a correlation with the output limit value PL. The state of charge SOC is calculated by a battery controller attached to the battery 21 and output to the control device 100. Note that the state of charge SOC can be calculated by a well-known method, such as a current integration method. In this way, the control device 100 according to this modification sets the correction value C2 according to the state of charge SOC of the battery 21. With this configuration, it is possible to obtain the same effects as those of the first embodiment described above.

[0115] <Modification 2 of the First Embodiment> The control device 100 may set the correction value C2 based on signals corresponding to a plurality of operating modes with different output limit values ​​PL. The wheel loader 1 according to this modified example is equipped with an input device that can select either a normal mode used during normal use, or a power mode in which power is prioritized. The input device outputs a mode selection signal to the control device 100 in response to operation by the operator. When a power mode selection signal is input, the control device 100 sets the output limit value PL to the maximum value Pmax. When a normal mode selection signal is input, the control device 100 sets the output limit value PL to a normal value Pn that is less than the maximum value Pmax.

[0116] In the wheel loader 1 according to this modification, if the increase in the traveling drive force from the normal mode is greater than the increase in the work drive force in power mode, it is assumed that the rise-run distance in power mode will be longer than the target rise-run distance. In this case, a correction value table T20 such as that shown in FIG. 13A is stored in the non-volatile memory 102. As shown in FIG. 13A, the traveling correction value table Tc20 defines a characteristic such that the traveling correction value Cc2 is 1.0 when the operation mode is normal mode, and is greater than 1.0 when the operation mode is power mode. As shown in FIG. 13A, the work correction value table Ti20 defines a characteristic such that the work correction value Ci2 is 1.0 when the operation mode is normal mode, and is less than 1.0 when the operation mode is power mode.

[0117] In this way, in a wheel loader 1 in which the increase in traveling drive force is greater than the increase in work drive force when the output limit value PL of the battery 21 increases, the control device 100 according to this modified example sets a traveling correction value Cc2 that increases the amount of suppression of the traveling drive force and a work correction value Ci2 that decreases the amount of suppression of the work drive force as the output limit value PL of the battery 21 increases. As a result, even in a state in which the output limit value PL of the battery 21 has increased, the actual rise run distance can be made to approach the target rise run distance by sufficiently slowing the vehicle speed and suppressing a decrease in the arm raising speed. According to this modified example, as with the above embodiment, the rise run distance can be kept constant regardless of changes in the output limit value PL of the battery 21, thereby improving work efficiency.

[0118] Note that while this modified example has been described based on normal mode, the following applies when the power mode is used as the basis. In a wheel loader 1 in which the amount of suppression of the traveling drive force when the output limit value PL of the battery 21 is reduced becomes greater than the amount of suppression of the work drive force, the control device 100 according to this modified example sets a traveling correction value Cc2 that decreases the amount of suppression of the traveling drive force and a work correction value Ci2 that increases the amount of suppression of the work drive force as the output limit value PL of the battery 21 decreases. As a result, even when the output limit value PL of the battery 21 is reduced, the rise run time is extended and a decrease in vehicle speed is suppressed, making it possible to bring the actual rise run distance closer to the target rise run distance.

[0119] On the other hand, if the increase in traveling drive force is smaller than the increase in work drive force in power mode, it is expected that the rise run distance in power mode will be shorter than the target rise run distance. In this case, a correction value table T20 such as that shown in FIG. 13B is stored in the non-volatile memory 102. As shown in FIG. 13B, the traveling correction value table Tc20 defines a characteristic such that the traveling correction value Cc2 is 1.0 when the operation mode is normal mode, and is smaller than 1.0 when the operation mode is power mode. As shown in FIG. 13B, the work correction value table Ti20 defines a characteristic such that the work correction value Ci2 is 1.0 when the operation mode is normal mode, and is larger than 1.0 when the operation mode is power mode.

[0120] In this way, in a wheel loader 1 in which the increase in traveling drive force when the output limit value PL of the battery 21 increases is smaller than the increase in work drive force, the control device 100 according to this modified example sets a traveling correction value Cc2 that decreases the amount of suppression of the traveling drive force and a work correction value Ci2 that increases the amount of suppression of the work drive force as the output limit value PL of the battery 21 increases. As a result, even when the output limit value PL of the battery 21 has increased, the rise run time is extended and a decrease in vehicle speed is suppressed, making it possible to bring the actual rise run distance closer to the target rise run distance. According to this modified example, as with the above embodiment, the rise run distance can be kept constant regardless of changes in the output limit value PL of the battery 21, thereby improving work efficiency.

[0121] Note that while this modified example has been described based on normal mode, the following applies when the power mode is used as the basis. In a wheel loader 1 in which the amount of suppression of the traveling drive force when the output limit value PL of the battery 21 is reduced is smaller than the amount of suppression of the work drive force, the control device 100 according to this modified example sets a traveling correction value Cc2 that increases the amount of suppression of the traveling drive force and a work correction value Ci2 that decreases the amount of suppression of the work drive force as the output limit value PL of the battery 21 decreases. As a result, even in a state in which the output limit value PL of the battery 21 has decreased, the actual rise run distance can be made to approach the target rise run distance by sufficiently slowing the vehicle speed and suppressing a decrease in the arm raising speed.

[0122] 13A and 13B, two types of operation modes, a normal mode and a power mode, are described, but there may be three or more types of operation modes. For example, in addition to the normal mode and the power mode, an eco mode that is set when priority is given to energy efficiency (electricity cost) may be provided.

[0123] The control device 100 according to this modification changes the output limit value PL of the battery 21 in accordance with the selected operation mode, and sets the correction value C2 in accordance with the operation mode. With this configuration, it is possible to appropriately perform constant rise run distance control in accordance with the operation mode.

[0124] Second Embodiment A wheel loader 1 according to a second embodiment of the present invention will be described with reference to Figure 14. Figure 14 is a system configuration diagram of a wheel loader 1 according to the second embodiment. Note that components that are the same as or equivalent to those described in the first embodiment are given the same reference symbols, and differences will be mainly described. In the first embodiment, an example in which the power source PS0 is a battery 21 is described. In this second embodiment, an example in which the power source PS0 is an engine 221 will be described.

[0125] 14, the wheel loader 1 is equipped with an engine 221 as a power source PS0, a traveling driving force supply device PS1 that supplies traveling driving force to the traveling devices 14, and a work driving force supply device PS2 that supplies work driving force to the work devices 6. The engine 221 is configured by an internal combustion engine such as a diesel engine, for example.

[0126] The traveling drive force supply device PS1 has a generator 220 mechanically connected to the engine 221, a traveling motor 11, and an inverter 222 that controls the generator 220 and the traveling motor 11. The generator 220 generates electric power by being driven and rotated by the power of the engine 221, and supplies the generated electric power to the traveling motor 11 via the inverter 222. The inverter 222 has a power generation inverter circuit that controls the generator 220 based on a power generation voltage command input from the control device 200, and a traveling inverter circuit that controls the traveling motor 11 based on a traveling drive torque command input from the control device 200.

[0127] The work driving force supply device PS2 is composed of a hydraulic pump 228 mechanically connected to the engine 221. The hydraulic pump 228 is rotationally driven by the power of the engine 221 and discharges hydraulic oil. The hydraulic pump 228 is a variable displacement hydraulic pump that can change the discharge flow rate (displacement volume) per rotation.

[0128] The control device 100 according to the first embodiment limits the output torque of the travel motor 11 (i.e., the travel driving force) by controlling the travel inverter 22, and limits the output torque of the work motor 12 (i.e., the work driving force) by controlling the work inverter 23. In contrast, the control device 200 according to the second embodiment limits the work driving force by controlling the discharge capacity of the hydraulic pump 228.

[0129] The wheel loader 1 has a temperature sensor 256 that detects the temperature of the engine 221 and outputs a signal indicating the detection result to the control device 200.

[0130] The control device 200 according to the second embodiment sets the correction value C2 in a different way from the setting method according to the first embodiment. In the first embodiment, the output was limited due to a decrease in the state of charge SOC of the battery 21. In contrast, in the second embodiment, the output of the engine 221 is not limited due to a decrease in the remaining amount of fuel. However, the output is limited due to the temperature of the engine 221. Specifically, when the temperature detected by the temperature sensor 256 is equal to or higher than a predetermined temperature threshold, the control device 200 according to the present embodiment decreases the output limit value PL as the temperature increases. The control device 200 limits the output of the engine 221 by restricting the amount of fuel injected into the engine 221.

[0131] In an output-restricted state in which the output of the engine 221 is restricted, if the amount of suppression of the traveling drive force from the normal state is greater than the amount of suppression of the work drive force, it is expected that the rise run distance in the output-restricted state will be shorter than the target rise run distance. In this case, a correction value table T2 such as that shown in FIG. 10A is stored in the non-volatile memory 102. As shown in FIG. 10A, the traveling correction value table Tc2 defines a characteristic in which, when the output limit value PL is less than the threshold value Pth, the traveling correction value Cc2 decreases as the output limit value PL decreases. The work correction value table Ti2 defines a characteristic in which, when the output limit value PL is less than the threshold value Pth, the work correction value Ci2 increases as the output limit value PL decreases.

[0132] The traveling correction value table Tc2 and the work correction value table Ti2 define characteristics such that the traveling correction value Cc2 and the work correction value Ci2 are 1.0 when the output limit value PL is equal to or greater than the threshold value Pth. In other words, when the output limit value PL is equal to or greater than the threshold value Pth, the correction rate η is not substantially modified by the correction value C2. This is because, in this embodiment, even if the output limit value PL decreases as the temperature of the engine 221 increases, the output is not limited to a level that restricts the traveling drive torque and work drive torque of the wheel loader 1. When the output limit value PL decreases from the maximum value Pmax, the traveling drive torque and work drive torque are immediately restricted, and the correction value table T2 has characteristics such that the correction value C2 changes when the output limit value PL is less than the maximum value Pmax.

[0133] Thus, in the wheel loader 1 in which the suppression amount of the traveling drive force becomes greater than the suppression amount of the work drive force when the output limit value PL of the engine 221 decreases, the control device 200 according to this embodiment sets a traveling correction value Cc2 that decreases the suppression amount of the traveling drive force and a work correction value Ci2 that increases the suppression amount of the work drive force as the output limit value PL of the engine 221 decreases. As a result, even in a state in which the output limit value PL of the engine 221 has decreased, the rise run time is extended and a decrease in vehicle speed is suppressed, so that the actual rise run distance can be made to approach the target rise run distance.

[0134] On the other hand, in an output-limited state in which the output of the engine 221 is limited, if the amount of suppression of the traveling drive force is smaller than the amount of suppression of the work drive force, it is expected that the rise run distance in the output-limited state will be longer than the target rise run distance. In this case, a correction value table T2 such as that shown in FIG. 10B is stored in the non-volatile memory 102. As shown in FIG. 10B, the traveling correction value table Tc2 defines a characteristic in which, when the output limit value PL is less than the threshold value Pth, the traveling correction value Cc2 increases as the output limit value PL decreases. The work correction value table Ti2 defines a characteristic in which, when the output limit value PL is less than the threshold value Pth, the work correction value Ci2 decreases as the output limit value PL decreases.

[0135] Thus, in the wheel loader 1 in which the suppression amount of the traveling drive force when the output limit value PL of the engine 221 is reduced is smaller than the suppression amount of the work drive force, the control device 200 according to this embodiment sets a traveling correction value Cc2 that increases the suppression amount of the traveling drive force and a work correction value Ci2 that decreases the suppression amount of the work drive force as the output limit value PL of the engine 221 decreases. As a result, even in a state in which the output limit value PL of the engine 221 is reduced, the actual rise run distance can be made to approach the target rise run distance by sufficiently slowing down the vehicle speed and suppressing a decrease in the arm raising speed.

[0136] As described above, according to the second embodiment, in a wheel loader 1 that uses the engine 221 as the power source PS0, the rise run distance can be kept constant regardless of the vehicle class and the output limit value PL of the engine 221. In other words, it is possible to provide a wheel loader 1 that can keep the rise run distance constant even when the traveling performance and working performance change due to a change in vehicle class or a change in the output limit value PL of the power source PS0.

[0137] <Modification of the second embodiment> In the second embodiment described above, an example has been described in which the correction value C2 is set based on the output limit value PL, but the method of setting the correction value C2 is not limited to this. The control device 200 may calculate the correction value C2 based on the temperature of the engine 221, which has a correlation with the output limit value PL. The control device 200 sets the correction value C2 in accordance with the temperature of the engine 221 detected by the temperature sensor 256, thereby achieving the same effects as those of the second embodiment described above.

[0138] Third Embodiment A wheel loader 1 according to a third embodiment of the present invention will be described with reference to Figure 15. Figure 15 is a system configuration diagram of a wheel loader 1 according to the third embodiment. Components that are the same as or equivalent to those described in the second embodiment are given the same reference symbols, and differences will be mainly described. In the second embodiment, an example will be described in which the traveling drive force supply device PS1 includes a generator 220, an inverter 222, and a traveling motor 11. In this third embodiment, an example will be described in which the traveling drive force supply device PS1 includes a torque converter 327 that amplifies torque, and a transmission 325 that changes the speed of the torque output from the torque converter 327 and then transmits it.

[0139] 15, the wheel loader 1 is equipped with an engine 221 as a power source PS0, a traveling drive force supply device PS1 that supplies traveling drive force to the traveling devices 14, and a work drive force supply device PS2 that supplies work drive force to the work devices 6. The traveling drive force supply device PS1 is equipped with a torque converter 327 connected to the engine 221, and a transmission 325 that is provided between the torque converter 327 and the wheels 7 and that changes the speed of the output of the torque converter 327 and outputs it to the wheels 7.

[0140] The torque converter 327 is a well-known fluid clutch having an impeller, a turbine, and a stator, and has the function of amplifying the output torque relative to the input torque (torque transmitted from the engine 221), i.e., the function of making the torque ratio (= output torque / input torque) greater than 1. The transmission 325 is composed of a clutch mechanism having multiple clutches and a gear mechanism having multiple speed change gears, and switches the traveling direction and speed stage of the vehicle body. In other words, the transmission 325 changes the torque, rotational speed, and rotational direction of the output shaft of the torque converter 327 before transmitting them to the wheels 7.

[0141] The control device 200 according to the second embodiment limits the output torque of the travel motor 11 (i.e., the travel driving force) by controlling the inverter 222, and limits the work driving force by controlling the discharge capacity of the hydraulic pump 228. In contrast, the control device 300 according to the third embodiment limits the travel driving force by controlling the speed stage of the transmission 325.

[0142] In the third embodiment, when the output limit value PL decreases due to an increase in the temperature of the engine 221, the correction value C2 is set by the same method as in the second embodiment. Therefore, according to the third embodiment, similar to the second embodiment, the rise run distance can be kept constant even when the output limit value PL of the engine 221 changes.

[0143] The following modified examples are also within the scope of the present invention, and it is possible to combine the configuration shown in the modified example with the configuration described in the above embodiment, to combine the configurations described in the different embodiments above, or to combine the configurations described in the different modified examples below.

[0144] <Variation 1> In the above embodiment, an example has been described in which a control device (e.g., control device 100) calculates rise run distance L1 based on driving performance data Dc generated by accumulating driving data from rise run start time ts to rise run end time te, but the present invention is not limited to this. For example, control device 100 accumulates driving data and work data from time t0 when calibration mode is set to data acquisition end time t2, which is a predetermined time after the calibration mode is set (see FIG. 8). As a result, driving performance data Dc and work performance data Di from calibration mode setting time t0 to data acquisition end time t2 are generated (see FIG. 8).

[0145] 8 (hereinafter also referred to as the acquired performance data) includes data from the rise run start time ts to the rise run end time te. In the acquired performance data, the control device 100 determines the time when there is a time change in the arm angle θ from the work performance data Di (time series data of the arm angle θ) as the rise run start time ts, and the time when there is no more time change in the arm angle θ as the rise run end time te.

[0146] The control device 100 determines that there has been a change in the arm angle θ over time when the rate of change over time of the arm angle θ detected by the arm relative angle sensor 151 changes from a value less than a predetermined change rate threshold to a value equal to or greater than the change rate threshold. Furthermore, the control device 100 determines that there has been no change in the arm angle θ over time when the rate of change over time of the arm angle θ detected by the arm relative angle sensor 151 changes from a value equal to or greater than the change rate threshold to a value less than the change rate threshold.

[0147] The control device 100 extracts the rise run distance L1 (the distance traveled from the rise run start time ts to the rise run end time te) from the driving performance data Dc of the acquired performance data. In this manner, in this modification, the rise run distance L1 is extracted from the driving performance data Dc and the work performance data Di for a predetermined time width that includes the rise run operation period. According to this modification, as in the above embodiment, it is possible to appropriately calculate the distance ratio R that represents the difference in rise run distance L1 due to differences in vehicle class.

[0148] <Variation 2> Depending on the wheel loader 1, the traveling performance data Dc and working performance data Di acquired in the calibration mode may have non-linear characteristics. In such a wheel loader 1, it is preferable to change the calibration value C1 according to the time difference Δt between the remaining traveling time tc and the remaining working time ti. For example, the time difference Δt represented by the horizontal axis in FIG. 6 may be divided into predetermined time ranges, and a calibration value C1 may be set for each divided range. In this case, the control device 100 references a calibration value table T1 (see FIG. 9) defined for each divided range, and sets the calibration value C1 for each divided range based on the distance ratio R.

[0149] In this way, similar to the above embodiment, the control device 100 according to this modified example calculates the remaining time until the vehicle body 8 reaches the target rise run distance as the remaining traveling time tc based on the vehicle speed and the target rise run distance. Furthermore, the control device 100 calculates the remaining time until the arm 2 reaches the target arm angle θ0 as the remaining work time ti based on the arm angle θ and the target arm angle θ0. The control device 100 sets the traveling correction factor ηc and the work correction factor ηi based on the time difference Δt between the remaining traveling time tc and the remaining work time ti. The control device 100 according to this modified example then sets a calibration value C1 according to the magnitude of the time difference Δt between the remaining traveling time tc and the remaining work time ti. With this configuration, rise run distance constant control can be performed with higher accuracy than in a wheel loader 1 in which the traveling performance data Dc and the work performance data Di have nonlinear characteristics.

[0150] <Variation 3> In the above embodiment, an example has been described in which the correction value C0 used to correct the correction factor η is calculated. However, the control device 100 may directly correct the correction factor η using the calibration value C1 and the correction value C2 without calculating the correction value C0. For example, the control device 100 may calculate the corrected correction factor ηr by multiplying the correction factor η by the calibration value C1 and the correction value C2. Furthermore, the correction method is not limited to multiplying the correction factor η by the calibration value C1 and the correction value C2. As a correction method, a method of adding or subtracting the calibration value C1 and the correction value C2 to or from the correction factor η may also be adopted. In this case, real numbers are set for the calibration value C1 and the correction value C2.

[0151] <Variation 4> In the above embodiment, an example has been described in which the correction rate η, which is a control parameter used in the rise run distance constant control, is corrected by the calibration value C1 and the correction value C2. When the rise run distance constant control is performed taking into consideration not only the correction rate η but also other control parameters, it is preferable that the control parameters are also corrected by the calibration value C1 and the correction value C2 in the same way.

[0152] <Variation 5> In the above embodiment, an example has been described in which the travel calibration value Cc1 and the work calibration value Ci1 are set as the calibration value C1. However, the present invention is not limited to this. For example, one of the travel calibration value Cc1 and the work calibration value Ci1 may be omitted. In other words, the control device 100 may be configured to set at least one of the travel calibration value Cc1 and the work calibration value Ci1. That is, the control device 100 may be configured to correct at least one of the travel correction factor ηc and the work correction factor ηi based on the set calibration value C1. Also, for example, in FIG. 9, both the travel calibration value Cc1 and the work calibration value Ci1 are changed according to the distance ratio R. However, the work calibration value Ci1 may be set to 1.0 (a fixed value) regardless of the distance ratio R, and only the travel calibration value Cc1 may be changed according to the distance ratio R. Of course, the travel calibration value Cc1 may be set to a fixed value, and the work calibration value Ci1 may be changed. In either case, the calibration value table T1 must be prepared in advance.

[0153] <Variation 6> In the above embodiment, an example was described in which the driving correction value Cc2 and the work correction value Ci2 were set as the correction value C2. However, the present invention is not limited to this. For example, one of the driving correction value Cc2 and the work correction value Ci2 may be omitted. In other words, the control device 100 may be configured to set at least one of the driving correction value Cc2 and the work correction value Ci2. That is, the control device 100 may be configured to modify at least one of the driving correction factor ηc and the work correction factor ηi based on the set correction value C2. Furthermore, for example, in FIGS. 10A and 10B, both the driving correction value Cc2 and the work correction value Ci2 are varied according to the output limit value PL. However, the work correction value Ci2 may be set to 1.0 (a fixed value) regardless of the output limit value PL, and only the driving correction value Cc2 may be varied according to the output limit value PL. Of course, the driving correction value Cc2 may be set to a fixed value, and the work correction value Ci2 may be varied. In either case, the correction value table T2 must be prepared in advance. Similarly, in the correction value table T20 shown in FIGS. 13A and 13B, one of the driving correction value Cc2 and the work correction value Ci2 may be set to 1.0 (fixed value) regardless of the operation mode, and the other may be changed depending on the operation mode.

[0154] <Variation 7> In the above embodiment, an example has been described in which the control device 100 sets both the driving correction factor ηc and the work correction factor ηi, but the present invention is not limited to this. The control device 100 may be configured to set at least one of the driving correction factor ηc and the work correction factor ηi. In a configuration in which only the driving correction factor ηc is set, the control device 100 sets a driving calibration value Cc1 and a driving correction value Cc2. In addition, in a configuration in which only the work correction factor ηi is set, the control device 100 sets a work calibration value Ci1 and a work correction value Ci2.

[0155] <Variation 8> In the second modification of the first embodiment, an example has been described in which a method of setting the correction value C2 depending on the operation mode is adopted for a wheel loader 1 that uses a battery 21 as the power source PS0. However, in the wheel loaders 1 according to the second and third embodiments, a method of setting the correction value C2 depending on the operation mode may also be adopted.

[0156] <Variation 9> The arm relative angle sensor 151 is not limited to a potentiometer as long as it can detect the arm angle θ. For example, the arm relative angle sensor 151 may be configured by an inertial measurement unit (IMU) or a stroke sensor that detects the stroke of the arm cylinder 4.

[0157] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments. [Explanation of symbols]

[0158] 1...wheel loader (work vehicle), 2...arm (lift arm), 3...bucket, 4...arm cylinder (hydraulic cylinder), 5...bucket cylinder (hydraulic cylinder), 6...working device, 7...wheel, 8...vehicle body, 9...operator's cab, 11...traveling motor (electric motor), 12...working motor (electric motor), 14...traveling device, 21...battery (power source), 22...traveling inverter, 23...working inverter, 28...hydraulic pump, 100...control device, 101...processing device, 102...non-volatile memory (storage device), 103...volatile memory (storage device), 111...traveling device remaining work time calculation unit, 112... remaining work time calculation unit, 113... rise run determination unit, 114... correction factor setting unit, 115... torque calculation unit, 116... mode setting unit, 117... distance ratio calculation unit, 118... calibration value setting unit, 119... correction value setting unit, 120... correction value setting unit, 141... accelerator operation device, 141a... accelerator operation amount sensor, 144... arm operation device, 144a... arm operation amount sensor, 145... bucket operation device, 145a... bucket operation amount sensor, 147... mode switching device, 147a... operation position sensor, 148... vehicle speed sensor, 151... arm relative angle sensor sensor, 200...control device, 220...generator, 221...engine (power source), 222...inverter, 228...hydraulic pump, 256...temperature sensor, 300...control device, 325...transmission, 327...torque converter, C0...correction value, C1...calibration value, C2...correction value, Cc0...driving correction value, Cc1...driving calibration value, Cc2...driving correction value, Ci0...working correction value, Ci1...working calibration value, Ci2...working correction value, d0...target rise run distance (target driving distance), db0...target rise run distance (reference target rise run distance), Dc...driving performance data, Di... Work performance data, L1...rise run distance, Lb1...rise run distance (reference rise run distance), PL...output limit value, PS0...power source, PS1...traveling driving force supply device, PS2...working driving force supply device, R...distance ratio, Rb...reference distance ratio, T0...correction rate table, T1...calibration value table, T2, T20...correction value table, Tc0...traveling correction rate table, Tc1...traveling calibration value table, Tc2, Tc20...traveling correction value table, Tcr...traveling required torque, Tct...traveling target torque, Ti0...working correction rate table, Ti1...working calibration value table, Ti2,Ti20...Work correction value table, Tir...Work required torque, Tit...Work target torque, Tp...Output limit value table, tc...Remaining running time, te...Rise run end time (time when target arm angle is reached), ti...Remaining work time, ts...Rise run start time (time when arm starts to rise), Δt...Time difference, η...Correction rate (control parameter), ηc...Traveling correction rate, ηcr...Corrected traveling correction rate, ηi...Work correction rate, ηir...Corrected work correction rate, ηr...Correction correction rate

Claims

1. Wheels attached to the vehicle body, a driving force supply device for supplying driving force to the wheels; a working device having an arm attached to the vehicle body so as to be rotatable in the vertical direction; a work driving force supply device that supplies a work driving force to the work device; a vehicle speed sensor for detecting a vehicle speed; an arm relative angle sensor that detects an arm angle, which is the angle of the arm with respect to the vehicle body; a power source that supplies power to the traveling driving force supply device and the working driving force supply device; a control device that controls at least one of the traveling driving force supply device and the work driving force supply device so that the output of the power source does not exceed an output limit value, The control device setting at least one of a traveling correction factor for adjusting the traveling drive force and an operation correction factor for adjusting the operation drive force based on the vehicle speed detected by the vehicle speed sensor, the arm angle detected by the arm relative angle sensor, a predetermined target traveling distance, and a predetermined target arm angle; When the driving correction factor is set, the driving force of the driving force supply device is controlled based on the driving correction factor; In a work vehicle that controls the work driving force of the work driving force supply device based on the work correction rate when the work correction rate is set, The control device calculating a rise / run distance, which is a distance traveled from when the arm starts to rise until it reaches the target arm angle, based on the vehicle speed detected by the vehicle speed sensor and the arm angle detected by the arm relative angle sensor; Calculating a distance ratio, which is a value obtained by dividing the calculated rise run distance by the target running distance; a calibration value that increases the suppression amount of the driving force for traveling and a calibration value that decreases the suppression amount of the driving force for working as the distance ratio increases; In the work vehicle in which the suppression amount of the traveling drive force becomes larger than the suppression amount of the work drive force when the output limit value of the power source is reduced, at least one of a correction value that decreases the suppression amount of the traveling drive force and a correction value that increases the suppression amount of the work drive force is set as the output limit value of the power source decreases, In the work vehicle in which the suppression amount of the traveling drive force becomes smaller than the suppression amount of the work drive force when the output limit value of the power source is reduced, at least one of a correction value that increases the suppression amount of the traveling drive force and a correction value that decreases the suppression amount of the work drive force is set as the output limit value of the power source is reduced, correcting at least one of the traveling correction rate and the work correction rate based on the set calibration value and the set correction value; A work vehicle characterized by:

2. The work vehicle according to claim 1, The control device When the distance ratio is greater than a predetermined reference distance ratio, at least one of a calibration value that increases the suppression amount of the driving drive force and a calibration value that decreases the suppression amount of the work drive force is set, compared to when the driving correction rate and the work correction rate are not corrected using the calibration value; When the distance ratio is smaller than the reference distance ratio, at least one of a calibration value that decreases the suppression amount of the driving drive force and a calibration value that increases the suppression amount of the work drive force is set, compared to when the driving correction rate and the work correction rate are not corrected using the calibration value. A work vehicle characterized by:

3. The work vehicle according to claim 1, The control device calculating a remaining time until the vehicle body reaches the target traveling distance based on the vehicle speed and the target traveling distance; calculating a remaining time until the arm reaches the target arm angle based on the arm angle and the target arm angle as a remaining work time; setting the travel correction rate and the work correction rate based on the time difference between the remaining travel time and the remaining work time; setting the calibration value according to the magnitude of the time difference; A work vehicle characterized by:

4. The work vehicle according to claim 1, the power source is a battery; the driving force supply device includes a driving motor driven by power from the battery and a driving inverter that controls the driving motor, The work driving force supply device includes a work motor driven by power from the battery and a work inverter that controls the work motor. A work vehicle characterized by:

5. The work vehicle according to claim 4, the control device sets the correction value in accordance with a state of charge of the battery. A work vehicle characterized by:

6. The work vehicle according to claim 1, the power source is an engine, the work driving force supply device has a hydraulic pump driven by the engine, A work vehicle characterized by:

7. The work vehicle according to claim 6, The control device sets the correction value in accordance with the temperature of the engine. A work vehicle characterized by:

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