Work vehicle

Abstract

A work vehicle is provided with: an engine; a hydraulic pump driven by the engine; a hydraulic cylinder that performs extension and contraction operation by hydraulic oil discharged from the hydraulic pump; a work device that moves in accordance with the extension and contraction operation of the hydraulic cylinder; a traveling device that is driven independently of the work device; an electric motor that is driven by electric power emitted by the engine and that causes the traveling device to operate; and a control device that controls the hydraulic cylinder and the electric motor. The control device changes the distribution ratio of a first torque consumed by the work device and a second torque consumed by the traveling device in the torque output by the engine based on the reaction force received by the vehicle body to control the output of the hydraulic pump and the output of the electric motor.

Description

Technical Field

[0001] This invention relates to work vehicles. Background Technology

[0002] A known work vehicle comprises a traveling device for moving the vehicle body and a working device with a bucket and boom for digging sand, soil, etc. In such a work vehicle, engine power is distributed to the traveling device and the working device for digging operations. If the traveling drive force is too large and the working drive force is too small, it is difficult to lift the bucket, thus reducing work efficiency. On the other hand, if the traveling drive force is too small and the working drive force is too large, the bucket cannot penetrate the sand sufficiently, or the bucket is lifted before the sand has fully entered the bucket, thus reducing work efficiency.

[0003] Patent document 1 discloses the following method: based on the average bucket weight after the excavation operation, automatically setting the distribution ratio (characteristics P, N, L) of the driving force and the working force for the next excavation operation.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2012-233521 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] In the technology described in Patent Document 1, when repeated digging operations are performed, the current digging operation is conducted based on a distribution ratio of driving force and working force set according to the average bucket weight after the previous digging operation. Therefore, if the hardness of the object being dug in this operation differs from the hardness of the object being dug in the previous operation, the set distribution ratio deviates from the range suitable for digging the object in this operation, which may lead to a decrease in the efficiency of the digging operation.

[0009] The purpose of this invention is to improve the efficiency of excavation operations.

[0010] Methods for solving problems

[0011] One aspect of the present invention provides a work vehicle comprising: an engine mounted on a vehicle body; a hydraulic pump driven by the engine; a hydraulic cylinder that extends and retracts via hydraulic oil discharged from the hydraulic pump; a work device that moves according to the extension and retraction of the hydraulic cylinder; a travel device driven independently of the work device; an electric motor driven by electricity generated by the engine and causing the travel device to move; and a control device that controls the hydraulic cylinder and the electric motor. The control device controls the output of the hydraulic pump and the output of the electric motor by changing the distribution ratio of a first torque consumed by the work device and a second torque consumed by the travel device in the torque output by the engine, based on the reaction force acting on the vehicle body.

[0012] Invention Effects

[0013] According to the present invention, the efficiency of excavation operations can be improved. Attached Figure Description

[0014] Figure 1 This is a side view of a wheel loader.

[0015] Figure 2 This is a system structure diagram of a wheel loader.

[0016] Figure 3 This diagram illustrates the basic digging operations of a wheel loader.

[0017] Figure 4 This is a functional block diagram of the main controller in the first embodiment.

[0018] Figure 5 This is a diagram illustrating the bucket angle θ.

[0019] Figure 6 This is a diagram showing the torque distribution ratio table of the first embodiment.

[0020] Figure 7A This is a diagram illustrating an example of a pump requirement mapping used to calculate the required flow rate of a pump.

[0021] Figure 7B This is a diagram illustrating an example of the torque mapping of a driving motor used to calculate the required torque for driving.

[0022] Figure 8 This is a flowchart representing the torque determination process performed by the main controller.

[0023] Figure 9 This is a timing diagram showing the operation of the main controller in the first embodiment.

[0024] Figure 10This is a timing diagram showing the operation of the main controller in the second embodiment.

[0025] Figure 11 This is a functional block diagram of the main controller in the third embodiment.

[0026] Figure 12 This is a diagram showing the torque distribution ratio table of the third embodiment.

[0027] Figure 13 This is a functional block diagram of the main controller in the fourth embodiment.

[0028] Figure 14 This is a functional block diagram of the main controller in the fifth embodiment. Detailed Implementation

[0029] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Furthermore, in this embodiment, an example of an electrically driven wheeled loader will be described.

[0030] <First Implementation>

[0031] Reference Figures 1-9 The working vehicle of the first embodiment of the present invention will be described. Figure 1 This is a side view of a wheel loader. (For example...) Figure 1 As shown, the wheel loader 1 has a body 8 equipped with a traveling device 11 and a multi-joint type working device 6 installed at the front of the body 8. The body 8 is an articulated steering (body bending) body, having a front body 8A, a rear body 8B and a center joint 10 connecting the front body 8A and the rear body 8B.

[0032] On the rear hull 8B, a driver's cab 12 is mounted at the front, and an engine compartment 16 is mounted at the rear. An engine 20 is mounted in the engine compartment 16 (see reference). Figure 2 Hydraulic pumps 30A, 30B, and 30C driven by engine 20 (see reference) Figure 2 Hydraulic equipment such as valves.

[0033] Figure 2 This is a system structure diagram of wheel loader 1. (For example...) Figure 2As shown, the wheel loader 1 includes: an engine 20; a generator motor 40 mechanically connected to the engine 20; hydraulic pumps 30A, 30B, and 30C mechanically connected to the engine 20; a working device 6 driven by working oil discharged from the hydraulic pump 30A; a front control unit 31 for controlling the operation of the working device 6; a braking device 21 driven by working oil discharged from the hydraulic pump 30B; a brake control unit 32 for controlling the operation of the braking device 21; a steering device 22 driven by working oil discharged from the hydraulic pump 30C; a steering control unit 33 for controlling the steering device 22; and a travel device 11 driven by electricity generated by the generator motor 40.

[0034] The working device 6 and the traveling device 11 are driven independently of each other by the power of the engine 20. The engine 20 is, for example, an internal combustion engine such as a diesel engine.

[0035] like Figure 1 As shown, the working device 6 is mounted on the front body 8A. The working device 6 has a boom (hereinafter referred to as stick) 2 rotatably mounted on the front body 8A and a bucket 3 rotatably mounted on the stick 2. The stick 2 moves according to the extension and retraction of the stick cylinder 4, which is a hydraulic cylinder, and the bucket 3 moves according to the extension and retraction of the bucket cylinder 5, which is a hydraulic cylinder. In addition, one stick 2 and one stick cylinder 4 are provided on each side of the front body 8A. Furthermore, in this embodiment, a Z-link type (double-arm crank type) linkage mechanism is adopted as the linkage mechanism for operating the bucket 3.

[0036] Hydraulic cylinders 4 and 5 extend and retract using hydraulic fluid (pressure oil), which is supplied by engine 20 (see reference). Figure 2 The hydraulic pump 30A rotates to discharge the torque output.

[0037] The running gear 11 has a front wheel 7A (tire 7) mounted on the front body 8A, a rear wheel 7B (tire 7) mounted on the rear body 8B, and a power transmission device that transmits power from the running motor 43 to the tires 7. The power transmission device is configured to include an axle, a differential, a drive shaft, etc.

[0038] The travel motor 43 is an electric motor that is driven by the electricity generated by the generator motor 40 to rotate and operate the travel device 11. The generator motor 40 rotates by the torque output from the engine 20. In addition, the wheel loader 1 is steered by a steering device 22 having a pair of left and right hydraulic cylinders (hereinafter referred to as steering cylinders) 15 arranged to connect the front body 8A and the rear body 8B.

[0039] like Figure 2As shown, hydraulic pumps 30A, 30B, and 30C are mechanically connected to engine 20 and generator motor 40. Hydraulic pumps 30A, 30B, and 30C are driven by the torque output from engine 20 to discharge working oil, which serves as the working fluid. Furthermore, when generator motor 40 functions as an electric motor, the torque output from engine 20 and generator motor 40 is used to drive hydraulic pumps 30A, 30B, and 30C.

[0040] The front control unit 31 controls the pressure, flow rate, and flow direction of the working oil discharged from the hydraulic pump 30A. The brake control unit 32 controls the pressure, flow rate, and flow direction of the working oil discharged from the hydraulic pump 30B. The steering control unit 33 controls the pressure, flow rate, and flow direction of the working oil discharged from the hydraulic pump 30C.

[0041] The wheel loader 1 includes: a main controller 100, which is a control device for controlling the hydraulic cylinders 4 and 5 that actuate the working device 6 and the travel motor 43 that actuates the travel device 11; a generator inverter (inverter for generator motor) 41, which controls the generator motor 40 based on the generator voltage command input from the main controller 100; a travel inverter (inverter for travel motor) 42, which controls the torque of the travel motor 43 based on the travel drive torque command input from the main controller 100; and various operating components (50 to 59) which are installed in the cab 12.

[0042] The cab 12 is equipped with: a stick control lever 52 for driving the stick 2; a bucket control lever 53 for driving the bucket 3; a forward / reverse switch 51 for switching the forward (F) and reverse (R) directions of the vehicle body 8; an accelerator pedal 58 for accelerating the vehicle body 8; a brake pedal 59 for decelerating the vehicle body 8; a steering wheel 55 for indicating the left and right directions of travel of the vehicle body 8; a mode switch 57 for switching the torque distribution mode to either MANUAL or AUTO mode; a torque distribution ratio setting dial 54 for manually setting the ratio of the output torque of the engine 20 to the working device 6 and the traveling device 11; and a parking brake switch 56 for engaging the parking brake.

[0043] The main controller 100 comprises a microcomputer with a CPU (Central Processing Unit) 104 serving as operating circuitry, a ROM (Read Only Memory) 105 and RAM (Random Access Memory) 106 serving as storage devices, an input interface 107, an output interface 108, and other peripheral circuitry. Furthermore, the main controller 100 may consist of a single microcomputer or multiple microcomputers.

[0044] The ROM 105 of the main controller 100 is a non-volatile memory such as EEPROM, which stores programs capable of performing various operations. That is, the ROM 105 of the main controller 100 is a storage medium capable of reading programs that implement the functions of this embodiment. The RAM 106 is a volatile memory, a working memory that directly inputs and outputs data with the CPU 104. The RAM 106 temporarily stores the required data during the execution of the program by the CPU 104. Furthermore, the main controller 100 may also include storage devices such as flash memory or hard disk drives.

[0045] CPU 104 is a processing device that expands and executes the program stored in ROM 105 in RAM 106, and performs prescribed operations on the signals taken from input interface 107, ROM 105, and RAM 106 according to the program.

[0046] Operation signals and sensor signals are input to the input interface 107. The input interface 107 converts the input signals into signals that can be processed by the CPU 104. The output interface 108 generates an output signal corresponding to the calculation result of the CPU 104 and outputs the signal to the front control unit 31, braking control unit 32, steering control unit 33, generator inverter 41, and driving inverter 42.

[0047] The main controller 100 controls the front control unit 31, braking control unit 32, steering control unit 33, power generation inverter 41, and driving inverter 42 in a unified manner based on the operation signals input by the operator and the sensor signals detected by various sensors.

[0048] As operation signals input to the main controller 100, there are acceleration signals output from the accelerator pedal 58 indicating the amount of operation of the accelerator pedal 58, braking signals output from the brake pedal 59 indicating the amount of operation of the brake pedal 59, stick signals output from the stick control lever 52 indicating the amount of operation of the stick control lever 52, bucket signals output from the bucket control lever 53 indicating the amount of operation of the bucket control lever 53, steering signals output from the steering wheel 55 indicating the amount of operation of the steering wheel 55, and travel direction signals output from the forward / reverse switch 51 indicating the operating position of the forward / reverse switch 51. Additionally, as operation signals input to the main controller 100, there are mode switching signals output from the mode switch 57 indicating the operating position of the mode switch 57, and ratio setting signals output from the torque distribution ratio setting dial 54 indicating the operating position of the torque distribution ratio setting dial 54.

[0049] As sensor signals input to the main controller 100, there are signals indicating the angle detected by the stick relative angle sensor 62, which is installed on the connecting shaft connecting the vehicle body 8 and the stick 2, and signals indicating the angle detected by the bucket relative angle sensor 63, which is installed on the connecting shaft connecting the stick 2 and the bucket 3. The stick relative angle sensor 62 detects the relative angle (tilt angle) of the stick 2 relative to the vehicle body 8 and outputs a signal indicating the detected angle to a potentiometer in the main controller 100. The bucket relative angle sensor 63 detects the relative angle (tilt angle) of the bucket 3 relative to the stick 2 and outputs a signal indicating the detected angle to a potentiometer in the main controller 100. Since the angle of the vehicle body 8 relative to the ground (driving surface) is fixed, it can be said that the angle detected by the stick relative angle sensor 62 is equivalent to the relative angle (tilt angle) of the stick 2 relative to the ground.

[0050] In addition, as sensor signals input to the main controller 100, there is a signal indicating the vehicle speed detected by the vehicle speed sensor 61. The vehicle speed sensor 61 detects the vehicle speed (travel speed) of the wheel loader 1 and outputs a signal indicating the detected vehicle speed to the main controller 100. Furthermore, as sensor signals input to the main controller 100, there are signals indicating the rotational speeds of the engine 20, generator motor 40, hydraulic pumps 30A, 30B, 30C, and travel motor 43 detected by multiple speed sensors, and signals indicating the discharge pressure of the hydraulic pumps 30A, 30B, 30C and the pressure (load pressure) of the hydraulic cylinders detected by multiple pressure sensors.

[0051] The main controller 100 outputs forward control commands based on the operating direction and amount of the operating levers 52 and 53. The forward control unit 31, based on the forward control commands from the main controller 100, adjusts the pressure, speed, and direction of the working oil discharged from the hydraulic pump 30A, thereby actuating the boom cylinder 4 and bucket cylinder 5. The forward control unit 31 includes a directional control valve that controls the flow of the working oil discharged from the hydraulic pump 30A, and a solenoid valve that generates pilot pressure input to the pilot chamber of the directional control valve.

[0052] The main controller 100 outputs braking control commands based on the operation amount of the brake pedal 59 and the operating position of the parking brake switch 56. The brake control unit 32, based on the braking control commands from the main controller 100, adjusts the pressure, speed, and direction of the working oil discharged from the hydraulic pump 30B, thereby actuating the hydraulic cylinders 17 and 18 that function the brake 13 and parking brake 14. The brake control unit 32 includes a directional control valve that controls the flow of the working oil discharged from the hydraulic pump 30B, and a solenoid valve that generates pilot pressure input to the pilot chamber of the directional control valve.

[0053] The main controller 100 outputs steering control commands based on the direction and amount of steering wheel 55 operation. The steering control unit 33, based on the steering control commands from the main controller 100, adjusts the pressure, speed, and direction of the working oil discharged from the hydraulic pump 30C, thereby actuating the steering cylinder 15. The steering control unit 33 includes a directional control valve that controls the flow of the working oil discharged from the hydraulic pump 30C, and a solenoid valve that generates pilot pressure input to the pilot chamber of the directional control valve.

[0054] Thus, in this embodiment, the torque output by the engine 20 is used to drive the hydraulic pumps 30A, 30B, and 30C, and the working oil discharged from the hydraulic pumps 30A, 30B, and 30C is used to drive the working device 6, the braking device 21, and the steering device 22.

[0055] The generator inverter 41 and the travel inverter 42 are connected via a DC bus 44. Furthermore, the wheel loader 1 of this embodiment does not have an energy storage device connected to the DC bus 44. The generator inverter 41 controls the bus voltage of the DC bus 44 using power supplied from the generator motor 40, based on a generator voltage command from the main controller 100. The travel inverter 42 drives the travel motor 43 using power from the DC bus 44, based on a travel drive torque command from the main controller 100.

[0056] Thus, in this embodiment, the torque output by the engine 20 drives the generator motor 40, and the electricity generated by the generator motor 40 drives the drive motor 43.

[0057] When the stick control lever 52 is operated, the stick 2 rotates vertically (pitch motion) through the extension and retraction of the stick cylinder 4. When the bucket control lever 53 is operated, the bucket 3 rotates vertically (loading or unloading action) through the extension and retraction of the bucket cylinder 5.

[0058] When the steering wheel 55 is operated, the front body 8A bends (steers) relative to the rear body 8B with the center joint 10 as the center. The tires 7 rotate through the drive of the drive motor 43, causing the wheel loader 1 to move forward and backward.

[0059] With the forward / reverse switch 51 activated on the forward side, pressing the accelerator pedal 58 will cause the tire 7 to rotate in the forward direction, and the vehicle body 8 to move forward. With the forward / reverse switch 51 activated on the reverse side, pressing the accelerator pedal 58 will cause the tire 7 to rotate in the reverse direction, and the vehicle body 8 to move backward.

[0060] The mode switching switch 57 is a mode switching operation unit that can manually switch between AUTO mode (first control mode) and MANUAL mode (second control mode). The AUTO mode is based on the reaction force F acting on the body 8 of the wheel loader 1. R The mode that controls the operating drive torque and driving drive torque, MANUAL mode, is related to the reaction force F. R The working drive torque and the driving drive torque are controlled independently to maintain the ratio of the working drive torque and the driving drive torque at a predetermined ratio.

[0061] Furthermore, the working drive torque is equivalent to the torque consumed by the working device 6 (first torque) of the torque output by the engine 20. That is, in this embodiment, the working drive torque is equivalent to the input torque of the hydraulic pump 30A. The travel drive torque is equivalent to the torque consumed by the travel device 11 (second torque) of the torque output by the engine 20. That is, in this embodiment, the travel drive torque is equivalent to the output torque of the travel motor 43.

[0062] The mode switch 57 has an AUTO mode position and a MANUAL mode position. When the mode switch 57 is operated to the AUTO mode position, a signal indicating that AUTO mode has been selected is output to the main controller 100. In this case, the main controller 100 sets AUTO mode as the torque distribution mode. When the mode switch 57 is operated to the MANUAL mode position, a signal indicating that MANUAL mode has been selected is output to the main controller 100. In this case, the main controller 100 sets MANUAL mode as the torque distribution mode.

[0063] The torque distribution ratio setting dial 54 is used to set the torque distribution ratio η used when the torque distribution mode is set to MANUAL mode. CS The operating components. The main controller 100 sets the set value η of the driving torque distribution ratio based on the operating position of the torque distribution ratio setting dial 54. CS Furthermore, the main controller 100 sets the set value η of the distribution ratio of the operating drive torque. IS The main controller 100 uses a set value η, which is the distribution ratio of the driving torque minus 100 [%). CS [%], calculate the set value η of the distribution ratio of the working drive torque. IS (100﹣η CS =η IS [%]). The main controller 100 will set the torque distribution ratio η. CS η IS Stored in ROM105.

[0064] Next, refer to Figure 3 The basic digging operation of wheel loader 1 is explained. In the digging operation of wheel loader 1, firstly, as... Figure 3 As shown in (a), the wheel loader 1 is moved toward the excavation target 91, such as a sand dune or a hill. Then, as... Figure 3 As shown in (b), the bucket 3 is inserted into the object 91 to be excavated, and the boom 2 and bucket 3 are operated to load materials such as sand into the bucket 3. Finally, as... Figure 3 As shown in (c), to prevent the sand and other transported materials entering the bucket 3 from spilling, the bucket 3 is scooped up (loading action) to complete the excavation operation. After the excavation operation is completed, the wheel loader 1 is temporarily reversed, and then moved towards a dump truck or other transport vehicle. At this time, the operator operates the boom control lever 52 to raise the boom 2, and simultaneously operates the steering wheel 55 to move the wheel loader 1 towards the dump truck. After the wheel loader 1 stops in front of the dump truck, the operator operates the bucket control lever 53 to tilt the bucket 3, thereby loading the transported materials in the bucket 3 into the cargo box of the dump truck (i.e., unloading the sand and soil in the bucket 3). When the loading operation is completed, the operator reverses the wheel loader 1 again, returning it to its original position.

[0065] The series of operations, including excavation and loading, constitutes the majority of the total operating time of the wheel loader 1. Therefore, improving the efficiency of this series of operations is effective in order to improve the operating efficiency of the wheel loader 1. Furthermore, operating efficiency refers, for example, to the weight of excavated material loaded onto the transport vehicle per unit time [ton / h] in the series of operations, including excavation and loading; the greater the weight, the more material can be excavated in a shorter time.

[0066] Here, if there is a imbalance between the driving force of the traveling device 11 (travel driving force) and the driving force of the working device 6 (working driving force), the efficiency of the excavation operation will decrease. For example, if the travel driving force is insufficient and the working driving force is excessive, the bucket 3 cannot fully penetrate the object 91 being excavated, or the bucket 3 may be lifted onto the object 91 before the sand and soil have fully entered the bucket 3, thus reducing the efficiency of the operation. On the other hand, if the working driving force is insufficient and the travel driving force is excessive, it will take time to lift the bucket 3, thus reducing the efficiency of the operation. Thus, if there is a imbalance between the travel driving force and the working driving force, the efficiency of the operation will decrease.

[0067] Therefore, in this embodiment, by properly balancing the driving force (driving force) of the travel device 11 required to properly penetrate the bucket 3 into the excavation object 91 and the driving force (operational driving force) of the working device 6 required to load a large amount of sand into the bucket 3 in a short time, the efficiency of the excavation operation in the above series of operations is improved.

[0068] Furthermore, the appropriate balance between driving force and working force varies depending on the hardness of the object being excavated 91. The harder the object being excavated 91, the greater the driving force required. The hardness of the object being excavated 91 manifests as the reaction force exerted on the wheel loader 1's body 8 by the object being excavated 91 during excavation operations. The harder the object being excavated 91, the greater the reaction force acting on the wheel loader 1's body 8. In this embodiment, during excavation operations, the balance between driving force and working force is adjusted based on the reaction force acting on the wheel loader 1's body 8, thereby improving work efficiency.

[0069] Figure 4 This is a functional block diagram of the main controller 100. (Example) Figure 4 As shown, the main controller 100 executes a program stored in ROM 105 to calculate the reaction force F acting on the body 8 of the wheel loader 1. R The reaction force calculation unit 131 and the digging state determination unit 132 determine whether the wheel loader 1 is in a digging operation state. The reaction force F calculated by the reaction force calculation unit 131 is used to determine whether the wheel loader 1 is in a digging operation state. R To determine the distribution ratio η between the operating drive torque and the driving torque. I η C The torque distribution ratio calculation unit 133, and the distribution ratio η determined by the torque distribution ratio calculation unit 133. I η C The engine torque distribution calculation unit 134 performs its function of determining the operating drive torque command used to control the operating drive torque and the driving drive torque command used to control the driving drive torque.

[0070] The reaction force calculation unit 131 is based on the traction force F of the wheel loader 1. P Given the vehicle speed v, calculate the reaction force F acting on the body 8 of the wheel loader 1. R Calculate the reaction force F R An example of the method is given. Using the relationship between momentum and impulse, the reaction force F is calculated using the following equation (1). R .

[0071] [Formula 1]

[0072]

[0073] Where m is the mass of the wheel loader 1, t0 is the reference time, t1 is the time after a predetermined time has elapsed from the reference time t0, v0 is the vehicle speed of the wheel loader 1 at the reference time t0, and v1 is the vehicle speed of the wheel loader 1 at time t1. Furthermore, in this embodiment, the vehicle speed of the wheel loader 1 is detected by the vehicle speed sensor 61, but a rotary encoder that detects the rotational speed of the shaft constituting the power transmission device may also be provided, and calculations may be performed based on the information detected by the rotary encoder.

[0074] Traction force F P The driving force generated by the driving motor 43 is equivalent to the driving force, such as the output torque (driving torque) Tm of the driving motor 43 based on time t1, the overall reduction ratio λ, and the diameter Dt of the tire 7. The traction force F is calculated by the following formula (2). P .

[0075] [Formula 2]

[0076]

[0077] Furthermore, the overall reduction ratio λ is the ratio of the engine speed 20 to the tire speed 7. When a transmission is installed, it is calculated by multiplying the transmission's gear ratio by the reduction ratio (differential ratio). c is a coefficient used for unit conversion. The driving torque (motor output torque) Tm can be detected by a torque sensor or calculated based on the motor current detected by a current sensor.

[0078] Calculated reaction force F during excavation R In the process, the reaction force exerted by the excavated object 91 on the wheel loader 1 is dominant and is influenced by the hardness of the excavated object 91. The reference time t0 is the time when the wheel loader 1 inserts into the excavated object 91 (the time when the bucket 3 begins to penetrate into the excavated object 91).

[0079] The main controller 100 determines whether the wheel loader 1 has inserted into the excavation target 91 (i.e., whether the bucket 3 has begun to penetrate the excavation target 91) based on the amount of operation of the accelerator pedal 58 and the time rate of change of the vehicle speed v of the wheel loader 1. When the main controller 100 determines that the wheel loader 1 has inserted into the excavation target 91, the insertion flag is set to open. In addition, the main controller 100 sets the time when the insertion flag is set to open as the reference time t0. Furthermore, the insertion flag is set to close when the excavation determination flag described later is set to close.

[0080] The main controller 100 calculates the time change rate D of the vehicle speed v (=(vb-va) / (tb-ta)) by dividing the difference (vb-va) between the previous value va and the current value vb, which are repeatedly detected at a predetermined control cycle, by the time Δt (=tb-ta) from the time ta when the previous value va was detected to the time tb when the current value vb was detected. The main controller 100 determines that the wheel loader 1 has inserted the excavation target 91 if the amount of operation of the accelerator pedal 58 is above a predetermined threshold and the time change rate D of the vehicle speed v is above a predetermined threshold. The main controller 100 determines that the wheel loader 1 has not inserted the excavation target 91 if the amount of operation of the accelerator pedal 58 is less than a predetermined threshold, or if the time change rate D of the vehicle speed v is less than a predetermined threshold.

[0081] The digging state determination unit 132 determines whether the wheel loader 1 is in a digging operation state based on the angle θ of the bucket 3 (hereinafter also referred to as the bucket angle) and the pressure Pa of the bottom oil chamber of the boom cylinder 4 (hereinafter also referred to as the bottom pressure). Figure 2 As shown, the bottom pressure Pa of the boom cylinder 4 is detected by a pressure sensor 71, which is located on the oil line connecting the bottom oil chamber (not shown) of the boom cylinder 4 to the front control unit 31. The pressure sensor 71 outputs a detection signal to the main controller 100.

[0082] Figure 5 This is a diagram illustrating the bucket angle θ. (For example...) Figure 5 As shown, the bucket angle θ is the tilt angle of the bucket 3 relative to the reference plane 90. In this embodiment, the reference plane 90 is set to be parallel to the ground (driving surface). When the bottom surface of the cutting edge 39 of the bucket 3 is parallel to the reference plane 90, the bucket angle θ is 0°. If the bucket 3 rotates by a shoveling action, the bucket angle θ increases with this rotation. In other words, if the bucket 3 rotates by a dumping action, the bucket angle θ decreases with this rotation. The main controller 100 calculates the bucket angle θ based on the relative angle of the stick 2 relative to the reference plane 90 detected by the stick relative angle sensor 62 and the relative angle of the bucket 3 relative to the stick 2 detected by the bucket relative angle sensor 63.

[0083] When the bucket angle θ is within a predetermined angle range (lower threshold θa to upper threshold θb) and the bottom pressure Pa of the boom cylinder 4 is above a predetermined pressure threshold Pa0, the digging status determination unit 132 determines that digging operation has started and sets the digging determination flag to "on". The digging determination flag is set to "on" when the wheel loader 1 is performing digging operation and is set to "off" when the digging operation ends.

[0084] The lower threshold θa and upper threshold θb are set within a specified angle range based on the insertion posture of the working device 6. The insertion posture of the working device 6 is such that the bucket 3 is approximately parallel to the travel surface (ground) near the travel surface (ground). The lower threshold θa and upper threshold θb are pre-stored in ROM 105.

[0085] The bottom pressure Pa of the boom cylinder 4 increases as the wheel loader 1 inserts into the excavated object 91. The pressure threshold Pa0 is pre-stored in the ROM 105. The pressure threshold Pa0 can be, for example, approximately twice the bottom pressure of the boom cylinder 4 supporting the working device 6 when the bucket 3 is unloaded and in the insertion position.

[0086] That is, when the excavation status determination unit 132 detects that the wheel loader 1 has been inserted into the excavation target 91 due to the increase of the boom cylinder pressure while the working device 6 is in the insertion posture, it determines that the excavation operation has started.

[0087] After determining that excavation work has started, the excavation status determination unit 132 determines that excavation work has ended when the bucket angle θ reaches or exceeds the angle threshold θe (e.g., around 30°), and sets the excavation determination flag to off. Furthermore, when the main controller 100 sets the excavation determination flag to off, it also sets the insertion flag to off. The angle threshold θe is a threshold used to determine whether excavation work has ended; for example, it is the bucket angle θ at which the loading action of the bucket 3 can be completed and the bucket 3 is in a transport posture. In other words, after determining that excavation work has started, the excavation status determination unit 132 determines that excavation work has ended when it detects that the bucket 3 is in a transport posture.

[0088] The torque distribution ratio calculation unit 133 is based on the reaction force F calculated by the reaction force calculation unit 131. R The excavation determination flag set by the excavation status determination unit 132 and the torque distribution mode are used to calculate the distribution ratio η of the working drive torque. I [%] and the distribution ratio η of driving torque. C [%). Distribution ratio of operating drive torque η I Take values ​​from 0 to 100%. Similarly, the distribution ratio η of the driving torque is... C Use values ​​from 0 to 100%. The distribution ratio η of the operating drive torque. I The distribution ratio η of the driving torque to the driving torque C The sum is 100%.

[0089] When the AUTO mode is set as the torque distribution mode, the torque distribution ratio calculation unit 133 is based on the reaction force F calculated by the reaction force calculation unit 131. RTo set the allocation ratio η I η C .

[0090] Figure 6 It represents the distribution ratio η used to determine the driving torque. C and the distribution ratio η of the operating drive torque. I A graph showing the torque distribution ratio. (See the graph.) Figure 6 As shown by the solid line, the torque distribution ratio table represents the reaction force F acting on the body 8 of the wheel loader 1. R The distribution ratio η of the driving torque to the driving torque C The corresponding table. Furthermore, in Figure 6 In the diagram, the distribution ratio η of the working drive torque is recorded using dashed lines. I .

[0091] The ROM105 of the main controller 100 pre-stores... Figure 6 The torque distribution ratio table is shown below. Figure 6 As shown by the solid line, the torque distribution ratio table represents the reaction force F. R The larger the value, the greater the distribution ratio of driving torque η. C The table shows the characteristics that become larger. Additionally, the torque distribution ratio table is set to the reaction force F. R The larger it becomes, the higher the allocation ratio η. C The increase relative to the reaction force F R The rate of increase (slope) decreases. Therefore, it is possible to determine the reaction force F when the wheel loader 1 is inserted into the excavated object 91. R The increase in torque distribution ratio rapidly increases the driving force. The torque distribution ratio table is determined in advance through experiments, etc.

[0092] If the excavation determination flag is set to open, the torque distribution ratio calculation unit 133 refers to... Figure 6 The solid line shown in the table represents the distribution ratio of the driving torque, based on the reaction force F calculated by the reaction force calculation unit 131. R To calculate the distribution ratio η of the driving torque. C Additionally, the torque distribution ratio calculation unit 133 subtracts the distribution ratio η of the driving torque from 100 [%). C [%], from which the distribution ratio η of the working drive torque is calculated. I (100﹣η C =η I [%]). Reaction force F R The larger the value, the higher the driving torque distribution ratio η. C The larger the reaction force F, the greater the reaction force F. R The larger the value, the higher the distribution ratio η of the operating drive torque. I The smaller.

[0093] Therefore, when the AUTO mode is set as the torque distribution mode, during the digging operation of the wheel loader 1, the distribution ratio η C η I According to the reaction force F R It changes in real time in response to changes.

[0094] When the torque distribution ratio calculation unit 133 is set to MANUAL mode as the torque distribution mode, it stores the distribution ratio setting value η in ROM 105. CS η IS Set as the allocation ratio η C η I (η C =η CS η I =η IS That is, when the MANUAL mode is set, even if the reaction force F R Changes, distribution ratio η C η I It also remains a fixed value.

[0095] The engine torque distribution calculation unit 134 is based on the distribution ratio η calculated by the torque distribution ratio calculation unit 133. C η I Engine output torque TE, auxiliary machine required torque T AUX_REQ The required torque T for the operation I_REQ and the required torque T for driving C_REQ Calculate the operating drive torque command T I_COM and driving torque command T C_COM .

[0096] The main controller 100 calculates the engine output torque TE and the auxiliary machine required torque T. AUX_REQ The required torque T for the operation I_REQ and the required torque T for driving C_REQ The engine output torque TE is the maximum torque that can be output at the current engine speed. The main controller 100 calculates the engine output torque TE based on the engine speed detected by the engine torque sensor, referring to the engine output torque curve stored in ROM 105. The required torque T of the auxiliary machines is calculated based on the operating states of multiple auxiliary machines that operate using electricity generated by the generator motor 40. AUX_REQThe main controller 100 sets a target engine speed (e.g., 1800 rpm). The target engine speed set by the main controller 100 is output to an engine controller (not shown). The engine controller controls the fuel injection device (not shown) to make the engine speed detected by the engine speed sensor the target value.

[0097] The main controller 100 calculates the required torque T based on the operation of the boom control lever 52 and the operation of the bucket control lever 53. I_REQ . Figure 7A This diagram illustrates an example of a pump requirement map used to calculate the required flow rate of a pump. This pump requirement map is pre-stored in the ROM 105 of the main controller 100. The main controller 100 refers to... Figure 7A The pump required flow rate mapping shown determines the required flow rate based on the lever operation amount (lever signal). The pump required flow rate mapping is set such that the required flow rate is approximately proportional to the lever operation amount. A larger lever operation amount results in a larger required flow rate. Furthermore, the pump required flow rate mapping includes mappings based on the operation amount of the stick operating lever 52 and mappings based on the operation amount of the bucket operating lever 53; the larger of the flow rates determined by each mapping is determined as the required flow rate.

[0098] The main controller 100 calculates the hydraulic power requirement based on the pump's required flow rate and the discharge pressure of the hydraulic pump 30A detected by the pressure sensor, and calculates the required torque T based on the hydraulic power requirement and the engine speed of the engine 20 detected by the speed sensor. I_REQ The greater the lever operation, the higher the required torque T. I_REQ The larger.

[0099] The main controller 100 calculates the required driving torque T based on the rotational speed of the drive motor 43 and the input of the accelerator pedal 58 (acceleration signal). C_REQ . Figure 7B This diagram illustrates an example of the torque mapping of the drive motor 43 used to calculate the required driving torque. This torque mapping is pre-stored in the ROM 105 of the main controller 100. The ROM 105 stores multiple torque mappings (torque curves) corresponding to acceleration signals, so that the torque of the drive motor 43 increases or decreases accordingly with the increase or decrease of the acceleration signal. The torque mapping is set such that the greater the acceleration signal, the greater the required driving torque T. C_REQ The larger the value, the faster the speed of the driving motor 43, and the higher the required torque T for driving. C_REQ The smaller.

[0100] The main controller 100 selects the torque map (torque curve) corresponding to the magnitude of the acceleration signal (the magnitude of the operation of the accelerator pedal 58), and determines the required driving torque T based on the speed of the drive motor 43. C_REQFor example, when the accelerator pedal 58 is fully operated (when the acceleration signal is at its maximum), the torque mapping of the solid line is selected, and the required driving torque T is calculated based on the speed of the drive motor 43, referring to the selected torque mapping. C_REQ Furthermore, when a transmission is installed, the main controller 100 also considers the transmission's gear ratio when calculating the required driving torque T. C_REQ .

[0101] Figure 4 The engine torque distribution calculation unit 134 shown is based on the required torque T during operation. I_REQ and the distribution ratio η of the operating drive torque determined by the torque distribution ratio calculation unit 133. I Determines the target torque T of the operation I_TGT The target torque T is calculated using equation (3). I_TGT .

[0102] [Formula 3]

[0103] T I_TGT =T I_REQ ·η I …(3)

[0104] Engine torque distribution calculation unit 134 is based on driving requirement torque T C_REQ and the distribution ratio η of the driving torque determined by the torque distribution ratio calculation unit 133. C Determines the target torque T for driving. C_TGT The target torque T is calculated using equation (4). C_TGT .

[0105] [Formula 4]

[0106] T C_TGT =T C_REQ ·η C …(4)

[0107] Engine torque distribution calculation unit 134 calculates the target torque T. I_TGT Target torque T C_TGT Auxiliary machine requires torque T AUX_REQ Total target torque T SUM_TGT (T SUM_TGT =T I_TGT +T C_TGT +T AUX_REQ The engine torque distribution calculation unit 134 calculates the total target torque value T. SUM_TGT When the engine output torque TE is below the target torque T, the working torque will be... I_TGT As the working drive torque command T I_COM The output will be the target torque T. C_TGT As driving torque command TC_COM Output.

[0108] On the other hand, the engine torque distribution calculation unit 134 calculates the total target torque value T. SUM_TGT When the torque is greater than the engine output torque TE, the operating drive torque command T is determined. I_COM and driving torque command T C_COM So that the work drive torque command T I_COM Driving torque command T C_COM Auxiliary machine requires torque T AUX_REQ Total commanded torque value T SUM_COM It shall not exceed the engine output torque TE. An example of this determination method is given below.

[0109] The engine torque distribution calculation unit 134 will calculate the target torque T. I_TGT Subtract the operating drive torque correction value C I The obtained value is used as the work drive torque command T. I_COM Output, the operation drive torque correction value C I It is the total value of the target torque T SUM_TGT The amount exceeding the engine output torque TE (T) SUM_TGT -TE) multiplied by the allocation ratio η I And thus obtained. Additionally, the engine torque distribution calculation unit 134 will calculate the target driving torque T... C_TGT Subtract the driving torque correction value C C The obtained value is used as the driving torque command T. C_COM Output, driving torque correction value C C It is the total value of the target torque T SUM_TGT The amount exceeding the engine output torque TE (T) SUM_TGT -TE) multiplied by the allocation ratio η C And thus, without changing the operating drive torque command T. I_COM With driving torque command T C_COM The ratio, in terms of the total command torque T SUM_COM The operating drive torque command T is determined in a manner that does not exceed the engine output torque TE. I_COM and driving torque command T C_COM .

[0110] In addition, the total target torque value T SUM_TGT Operating drive torque command T when the engine output torque TE is greater than the operating torque TE I_COM and driving torque command T C_COM The method for determining this is not limited to this. For example, it can also be done by simply subtracting the target torque T. I_TGT and driving target torque T C_TGTThe correction of one side is based on the total command torque value T. SUM_COM The operating drive torque command T is determined in a manner that does not exceed the engine output torque TE. I_COM and driving torque command T C_COM .

[0111] Reference Figure 8 This explains the torque determination process performed by the main controller 100. Figure 8 The process shown in the flowchart begins when the ignition switch (engine key switch) is turned on, and after an initial setting (not shown), it is repeatedly executed at a predetermined control cycle. Furthermore, in the initial setting, the digging determination flag is set to off.

[0112] like Figure 8 As shown, in step S110, the main controller 100 calculates the reaction force F. R Proceed to step S120.

[0113] In step S120, the main controller 100 performs the setting process for the digging determination flag. If the bucket angle θ is not within a predetermined angle range (lower threshold θa to upper threshold θb), or if the bottom pressure Pa of the boom cylinder 4 is less than a predetermined pressure threshold Pa0, the main controller 100 determines that digging has not started. In this case, the main controller 100 keeps the digging determination flag off.

[0114] When the bucket angle θ is within a predetermined angle range (lower threshold θa to upper threshold θb) and the bottom pressure Pa of the boom cylinder 4 is above a predetermined pressure threshold Pa0, the main controller 100 determines that digging operation has started. In this case, the main controller 100 switches the digging determination flag from off to on.

[0115] If the setting process of the excavation determination flag is completed, proceed to step S130. In step S130, the main controller 100 determines whether the torque distribution mode is set to AUTO mode or MANUAL mode. If it is determined that the torque distribution mode is set to AUTO mode in step S130, proceed to step S140; if it is determined that the torque distribution mode is set to MANUAL mode, proceed to step S170.

[0116] In step S170, the main controller 100 stores the set value η in ROM 105. CS The allocation ratio η is determined. C And set the value η IS The allocation ratio η is determined. S Proceed to step S180.

[0117] In step S140, the main controller 100 determines whether the wheel loader 1 is in a state of digging. If the digging determination flag is set to "on" in step S140, the wheel loader 1 is considered to be in a state of digging, and the process proceeds to step S150. If the digging determination flag is set to "off" in step S140, the wheel loader 1 is considered not to be in a state of digging, and the process proceeds to step S160.

[0118] In step S150, the main controller 100 is based on the reaction force F R To determine the torque distribution ratio η C η I Proceed to step S180.

[0119] In step S160, the main controller 100 will set the reference value η C 0 (e.g., 50%) is determined as the allocation ratio η. C And set the reference value η S 0 (e.g., 50%) is determined as the allocation ratio η. S Proceed to step S180. Set the reference value η C 0, η S 0 is pre-stored in ROM105.

[0120] In step S180, the main controller 100 determines the allocation ratio η. C η I Engine output torque TE, auxiliary machine required torque T AUX_REQ The required torque T for the operation I_REQ and the required torque T for driving C_REQ Generate the operation drive torque command T I_COM and driving torque command T C_COM ,Finish Figure 8 The process is shown in the flowchart.

[0121] The work drive torque command T generated by the main controller 100 I_COM Output to a pump controller (not shown). The pump controller is based on the operating drive torque command T. I_COM The discharge pressure of hydraulic pump 30A is used to generate a control signal for controlling the discharge capacity (discharge) of hydraulic pump 30A. The pump controller controls the discharge capacity of hydraulic pump 30A by outputting the generated control signal to a regulator (not shown). Thus, the working device 6 (stick 2 and bucket 3) is driven by the working driving force generated by hydraulic cylinders 4 and 5. In this embodiment, the main controller 100 calculates the reaction force F acting on the wheel loader 1. R Based on reaction force F R The distribution ratio η of the working drive torque is determined. IBased on this allocation ratio η I Generate the operation drive torque command T I_COM This controls the operating torque.

[0122] The driving torque command T generated by the main controller 100 C_COM The output is sent to the driving inverter 42. The driving inverter 42 is based on the driving drive torque command T. C_COM The travel motor 43 is driven by the travel motor 43. The torque generated by the travel motor 43 is transmitted to the tires 7, which are part of the travel unit 11, via a power transmission device that is part of the travel unit 11. Thus, the travel unit 11 is driven by the travel driving force generated by the travel motor 43. In this way, the main controller 100 of this embodiment calculates the reaction force F acting on the wheel loader 1. R Based on reaction force F R The distribution ratio η of the driving torque determines the driving torque. C Based on this allocation ratio η C Generate driving torque command T C_COM To control the driving torque.

[0123] Reference Figure 9 The driving torque command and the working torque command of the wheel loader 1 in this embodiment when performing digging operations will be explained. Figure 9 This is a timing diagram illustrating the operation of the main controller 100 in this embodiment. To clarify the effects of this embodiment, the explanation will compare the operation with that of the main controller of the wheel loader in the comparative example of this embodiment. Furthermore, the wheel loader in the comparative example does not have an AUTO mode, and the allocation ratio η... C Set at 50%, allocation ratio η I Set at 50%, allocation ratio η C η I The operation remains unchanged during excavation. In the figure, the operation of the main controller 100 in this embodiment is represented by a solid line, and the operation of the main controller in the comparative example is represented by a dashed line.

[0124] Figure 9 The horizontal axis represents time (elapsed time). Figure 9 The vertical axis of (a) represents the reaction force F calculated by the main controller 100. R , Figure 9 The vertical axis of (b) represents the distribution ratio η of the driving torque determined by the main controller 100. C , Figure 9 The vertical axis of (c) represents the driving torque command T generated by the main controller 100. C_COM , Figure 9 The vertical axis of (d) represents the work drive torque command T generated by the main controller 100.I_COM .

[0125] Furthermore, in this embodiment and comparative example, the operator's operating sequence and amount of operation for various operating components are the same. Time T0 is the moment when the wheel loader 1 inserts into the excavation target 91, such as a sand dune (i.e., the moment when the bucket 3 begins to penetrate relative to the excavation target 91). That is, time T0 is the moment when the insertion flag is set to open. Time T1 is the moment when the excavation determination flag is set to open, and time T2 is the moment when the excavation determination flag is set to close. Time Ta is the moment when the operator begins operating the stick control lever 52. Additionally, at time T2, the operator switches the forward / reverse switch 51 from the forward position to the reverse position.

[0126] like Figure 9 As shown in (a), the reaction force F R Before time T0, the force is small. This is because before time T0, the wheel loader 1 is not in contact with the object being excavated 91, so only the reaction force from the moving ground (driving surface) is calculated. At time T0, the wheel loader 1 comes into contact with the object being excavated 91, so a repulsive force from the object being excavated 91 is added. Therefore, from time T0 onwards, the reaction force F... R The reaction force increases sharply. Furthermore, in this embodiment, the reaction force is calculated successively using time T0 as the reference time t0. For example, it is calculated based on the mass m of the wheel loader 1, the elapsed time (t1-t0) from time T0 (reference time t0), the vehicle speed v0 at time T0, the vehicle speed v1 at time Tb, and the traction force F. P The reaction force F at time Tb is calculated using the above formula (1). Rb .

[0127] In the comparative example, not based on the reaction force F R Determines the torque distribution ratio η C η I Therefore, in the comparative example, such as Figure 9 As shown in (b), the distribution ratio η of the driving torque is... C It is always a fixed value. Therefore, as... Figure 9 As shown in (c), the driving torque command is always a fixed value.

[0128] In contrast, in this embodiment, during the period from when the excavation determination flag is set to open until it is set to close (time T1 to time T2), that is, during the period when the main controller 100 determines that excavation work is in progress, the reaction force F R The larger it becomes, the greater the distribution ratio η of the driving torque. C It becomes larger. Therefore, from time T1 to time T2, the reaction force F... RThe larger the value, the greater the driving torque command. Furthermore, during other periods, the allocation ratio η in this embodiment... C The driving torque command is the same as in the comparative example.

[0129] Although not illustrated, in the comparative example, the distribution ratio η of the operating drive torque is... I It is always a fixed value. Therefore, as... Figure 9 As shown in (d), if the operation of the stick operating lever 52 begins (at time Ta), and the stick operating lever 52 is raised to a predetermined operating amount (e.g., the maximum operating amount), then in the comparative example, the work drive torque command becomes a fixed value. In contrast, in this embodiment, when the stick operating lever 52 is raised to the predetermined operating amount (e.g., the maximum operating amount) and held at that operating amount, with the reaction force F... R As the torque increases, the operating drive torque command decreases. Furthermore, in this embodiment, after time T2, the allocation ratio η... I The value is returned to the value prior to time T1. Therefore, after time T2, the operating torque command in this embodiment becomes the same value as the operating torque command in the comparative example.

[0130] As described above, in this embodiment, during excavation operations, the main controller 100 utilizes the reaction force F acting on the vehicle body 8 of the wheel loader 1. R Make the distribution ratio η C η I The working drive torque and the traveling drive torque are controlled by variations, thereby controlling the output of the hydraulic pump 30A and the output of the traveling motor 43. Therefore, the distribution ratio of traveling drive force to working drive force can be made close to a distribution ratio suitable for the hardness of the object being excavated 91, regardless of the operator's skill level, thus improving work efficiency. Furthermore, in this embodiment, the distribution ratio η... C η I The forces are adjusted sequentially, thus improving operational efficiency even when the excavation target 91 consists of multiple soil types with varying hardness. Furthermore, the reaction force F acting on the wheel loader 1's body 8... R Due to the influence of road surface conditions, according to this embodiment, even when the hardness of the object being excavated 91, the road surface conditions change with each excavation cycle, or change in real time during the excavation operation, the torque distribution ratio can be made close to an appropriate value, thereby improving work efficiency.

[0131] According to the above implementation method, the following effects are achieved.

[0132] (1) The wheel loader (operating vehicle) 1 includes: an engine 20 mounted on the vehicle body 8; a hydraulic pump 30A driven by the engine 20; hydraulic cylinders 4 and 5 that extend and retract by hydraulic oil discharged from the hydraulic pump 30A; an operating device 6 that moves according to the extension and retraction of the hydraulic cylinders 4 and 5; a traveling device 11 that is driven independently of the operating device 6; a traveling motor (electric motor) 43 that is driven by electricity generated by the engine 20 and that actuates the traveling device 11; and a main controller (control device) 100 that controls the hydraulic cylinders 4 and 5 and the traveling motor 43. The main controller 100 is based on the reaction force F acting on the vehicle body 8. R The distribution ratio η of the torque output by engine 20, consisting of the working drive torque (first torque) consumed by working device 6 and the driving drive torque (second torque) consumed by driving device 11, is adjusted. I η C The output of the hydraulic pump 30A and the output of the travel motor 43 are controlled by variations.

[0133] Therefore, even when repeatedly digging, including digging objects 91 with varying hardness, the power of the engine 20 can be appropriately distributed to the working device 6 and the traveling device 11. In other words, according to this embodiment, the efficiency of digging operations on objects 91 with varying hardness can be improved.

[0134] (2) Furthermore, even if the operator's skill level is low, and the operating amounts of the boom lever 52, bucket lever 53, and accelerator pedal 58 deviate from the appropriate operating amounts, the distribution of the working drive torque and the travel drive torque can still be made close to the appropriate distribution. As a result, the efficiency of excavation operations can be improved regardless of the operator's skill level.

[0135] (3) The main controller 100 determines whether the wheel loader 1 is in the state of digging. During the period when it is determined that the wheel loader 1 is in the state of digging (i.e., the period during which the wheel loader 1 is digging), a reaction force F is applied. R The operating drive torque and driving drive torque are controlled in a manner that the larger the value of the operating drive torque, the smaller the operating drive torque and the larger the driving drive torque. Therefore, even when the hardness of the object being excavated 91 changes in real time, the driving drive torque and operating drive torque can be appropriately set. Furthermore, according to this structure, even when road conditions change in real time, the driving drive torque and operating drive torque can be appropriately set.

[0136] (4) The wheel loader 1 is equipped with a mode switching switch (mode switching operation unit) 57 that can manually switch between AUTO mode (first control mode) and MANUAL mode (second control mode). The AUTO mode is based on the reaction force F RThe mode that controls the operating drive torque and the driving drive torque, MANUAL mode, is related to the reaction force F. R Independently control the operating drive torque and the driving drive torque to maintain the ratio of the operating drive torque and the driving drive torque at a predetermined ratio (e.g., a set value η). IS η CS Therefore, operators can distinguish between AUTO mode and MANUAL mode depending on the situation.

[0137] <Second Implementation>

[0138] Main reference Figure 10 The wheeled loader 1 of the second embodiment will be described. Furthermore, in the figures, the same reference numerals are used for parts that are the same as or equivalent to those in the first embodiment, and the main differences are explained. Figure 10 Is with Figure 9 The same diagram is a timing diagram showing the operation of the main controller 100 in the second embodiment.

[0139] The wheel loader 1 of the second embodiment has the same structure as the wheel loader 1 of the first embodiment, but the processing in the torque distribution ratio calculation unit 133 is different from that of the first embodiment. For example Figure 10 As shown, the torque distribution ratio calculation unit 133 calculates the reaction force F based on the time Tc after a predetermined time ΔTp elapsed from the moment T0 when the insertion flag is set to open. RC The distribution ratio η of the operating drive torque is determined. I and the distribution ratio η of driving torque. C The torque distribution ratio η is maintained from the time the excavation determination flag is turned on until it switches to off. I η C If the excavation determination flag is set from open to closed, the controller 100 will allocate ratio η. I η C Initialized to the base value η I 0, η C 0.

[0140] The predetermined time ΔTp can be appropriately set based on the operation content, performance, and computing power of the main controller 100 of the wheel loader 1. To improve calculation accuracy, a longer predetermined time ΔTp is better; for example, by ensuring approximately 0.1 seconds, the reaction force F can be calculated with a certain level of accuracy. RC Furthermore, the time from the insertion of the wheel loader 1 into the excavated object 91 to the end of the excavation operation (time T0 to time T2) is approximately 5 seconds. Therefore, the predetermined time ΔTp is preferably a value of 0.1 seconds or more and 5 seconds or less.

[0141] Furthermore, the time from when the wheel loader 1 inserts into the object 91 to when the boom 2 begins to rise is approximately 0.5 seconds, and the time from when the wheel loader 1 inserts into the object 91 to when the bucket 3 begins to load is approximately 1.5 seconds. Therefore, it is more preferable to set the predetermined time ΔTp within the range of 0.5 seconds or more and 1.5 seconds or less. In particular, by setting the predetermined time ΔTp to approximately 0.5 seconds, the torque distribution ratio can be quickly determined and reflected in the work drive torque command and the travel drive torque command.

[0142] Until the excavation determination flag switches from open to closed, the torque distribution ratio calculation unit 133 maintains the reaction force F calculated at time Tc. RC The calculated distribution ratio η I η C Therefore, even if the accelerator pedal 58 is released or the vehicle body is reversed during excavation operations, the reaction force temporarily acting on the wheel loader 1 during excavation operations is less than the reaction force F. RC Torque distribution ratio η I η C It will not change. Therefore, in a single excavation operation, if the wheel loader 1 moves forward and backward multiple times to scoop up sand, an appropriate torque distribution ratio η can be pre-set for subsequent sand scooping operations. I η C .

[0143] Thus, in the second embodiment, the main controller 100 determines whether the wheel loader 1 has inserted into the excavation target 91, based on the reaction force F after a predetermined time ΔTp elapsed from the time the wheel loader 1 is determined to have inserted into the excavation target 91 (from the time the insertion flag is set to open). RC This determines the distribution ratio η between the operating drive torque and the driving torque. I η C And control the operating drive torque and driving drive torque to maintain the distribution ratio η I η C This continues until the excavation operation is completed (until the excavation judgment flag is changed from on to off).

[0144] According to this second embodiment, excavation operations can be carried out in more working modes. That is, according to the second embodiment, in addition to the same effects as the first embodiment, the degree of freedom in excavation operations can be increased.

[0145] <Third Implementation Method>

[0146] Main reference Figure 11 and Figure 12The wheeled loader 1 of the third embodiment will be described. Furthermore, in the figures, the same reference numerals are used for parts that are the same as or equivalent to those in the first embodiment, and the main differences are explained. Figure 11 Is with Figure 4 The same diagram is a functional block diagram of the main controller 300 in the third embodiment.

[0147] like Figure 2 As shown, an overflow valve 72 is installed on the oil line connecting the bottom oil chamber (not shown) of the boom cylinder 4 to the front control unit 31. This overflow valve sets the maximum pressure of the bottom pressure Pa of the boom cylinder 4 to a predetermined overflow pressure. If the bottom pressure Pa of the boom cylinder 4 rises to the overflow pressure during the process of the wheel loader 1 inserting into the excavation target 91 and the bucket 3 penetrating the excavation target 91, the boom 2 may not be able to be lifted properly. Therefore, in the third embodiment, the torque distribution ratio η is determined by considering the bottom pressure Pa of the boom cylinder 4. I η C This allows for the appropriate lifting action of pole 2.

[0148] like Figure 11 As shown, when the excavation determination flag is set to open, the torque distribution ratio calculation unit 333 calculates the torque distribution ratio based on the reaction force F. R Calculate the torque distribution ratio η based on the bottom pressure Pa of the boom cylinder 4. I η C .

[0149] Figure 12 Is with Figure 6 The same diagram is a table showing the torque distribution ratio in the third embodiment. For example... Figure 12 As shown, ROM105 stores multiple torque distribution ratio tables corresponding to the magnitude of the bottom pressure Pa of the boom cylinder 4, so that the distribution ratio η of the driving torque is adjusted. C The pressure Pa at the bottom of the boom cylinder 4 changes accordingly.

[0150] The main controller 300 selects the torque distribution ratio table corresponding to the magnitude of the bottom pressure Pa of the boom cylinder 4, based on the reaction force F. R To determine the distribution ratio η of the driving torque. C The torque distribution ratio table is set so that the reaction force F R The larger the value, the higher the driving torque distribution ratio η. C The larger the pressure Pa at the bottom of the boom cylinder 4, the higher the distribution ratio η of the driving torque. C The smaller.

[0151] Therefore, in the wheel loader 1 of the third embodiment, during the initial stage of the bucket 3 penetrating the object 91 being excavated, the bottom pressure Pa of the boom cylinder 4 is relatively small, and thus the distribution ratio η of the driving torque is relatively small. C The pressure increases. Furthermore, from the intermediate stage of the bucket 3 penetrating the object 91 to the final stage, the bottom pressure Pa of the boom cylinder 4 increases, thus increasing the distribution ratio η of the driving torque. C It gets smaller.

[0152] Thus, in the third embodiment, the main controller 300 controls the travel drive torque in such a way that the greater the pressure of the stick cylinder (hydraulic cylinder) 4 that actuates the stick 2, the smaller the travel drive torque. The closer the bottom pressure Pa of the stick cylinder 4 is to the overflow pressure, the smaller the travel drive torque is, thereby reducing the bottom pressure Pa of the stick cylinder 4, and thus enabling the stick 2 to rise appropriately.

[0153] According to this third embodiment, when the sand loaded into the bucket 3 is heavy, or when the boom lifting operation is delayed, it can prevent or delay the situation where the boom 2 lifting action (bucket 3 rising) becomes impossible due to the bottom pressure Pa of the boom cylinder 4 reaching its maximum pressure (overflow pressure) due to the increase in driving force. Therefore, according to the third embodiment, in addition to the same effects as the first embodiment, it is also possible to suppress the decrease in the efficiency of the bucket 3 in the digging operation relative to the object 91 from the intermediate stage to the final stage.

[0154] Furthermore, in this embodiment, the distribution ratio η of the driving torque is determined by selecting a table corresponding to the bottom pressure Pa of the boom cylinder 4 from multiple torque distribution ratio tables. C The method was explained, but the allocation ratio η C The method for determining the distribution ratio is not limited to this. For example, the distribution ratio that serves as a reference can also be determined based on the torque distribution ratio table described in the first embodiment, and the distribution ratio η can be determined by multiplying the distribution ratio that serves as a reference by a coefficient preset according to the bottom pressure Pa of the boom cylinder 4. C .

[0155] <Fourth Implementation>

[0156] Main reference Figure 13 The wheeled loader 1 of the fourth embodiment will be described. Furthermore, in the figures, the same reference numerals are used for parts that are the same as or equivalent to those in the first embodiment, and the main differences are explained. Figure 13 Is with Figure 4 The same diagram is a functional block diagram of the main controller 400 in the fourth embodiment.

[0157] The main controller 400 in the fourth embodiment also has an upper limit value T that determines the operating drive torque.I_LIM and the upper limit of driving torque T C_LIM The function of the torque upper limit calculation unit 433.

[0158] Torque upper limit calculation unit 433 calculates the difference between the engine output torque TE and the auxiliary machine required torque T. AUX_REQ The obtained value is the difference ΔTE (ΔTE = TE - T). AUX_REQ ).

[0159] The torque upper limit calculation unit 433 calculates the distribution ratio η of the operating drive torque determined by the torque distribution ratio calculation unit 133. I Multiply by the difference value ΔTE to calculate the upper limit value T of the working drive torque. I_LIM (T I_LIM =ΔTE·η I ).

[0160] The torque upper limit calculation unit 433 calculates the driving drive torque distribution ratio η determined by the torque distribution ratio calculation unit 133. C Multiply by the difference value ΔTE to calculate the upper limit value T of the driving torque. C_LIM (T C_LIM =ΔTE·η C ).

[0161] Engine torque distribution calculation unit 434 is based on the required torque T for operation. I_REQ and the upper limit value T of the operating drive torque determined by the upper limit value calculation unit 433 I_LIM Determines the target torque T of the operation I_TGT Target torque T I_TGT Calculated using equation (5).

[0162] [Formula 5]

[0163]

[0164] Engine torque distribution calculation unit 434 is based on driving requirement torque T C_REQ and the upper limit value T of the driving torque determined by the upper limit value calculation unit 433. C_LIM Determines the target torque T for driving. C_TGT Target torque T C_TGT Calculated using equation (6).

[0165] [Formula 6]

[0166]

[0167] Thus, the main controller 400 in the fourth embodiment is based on the reaction force F R The upper limit T of the operating drive torque is determined. I_LIMand the upper limit of driving torque T C_LIM And based on the upper limit value T of the operating drive torque. I_LIM and the upper limit of driving torque T C_LIM It controls the operating drive torque and the driving drive torque. Specifically, the main controller 400 controls the operating drive torque based on the upper limit value T. I_LIM and the upper limit of driving torque T C_LIM Controlling the operating drive torque and the driving drive torque, thereby enabling the application of reaction force F R This changes the distribution ratio of the operating drive torque and the driving torque.

[0168] In the fourth embodiment, during excavation operations, if the required torque for operation and the required torque for travel exceed the upper limit value (T)... I_LIM T C_LIM Then, the operating drive torque and the driving drive torque are controlled to make the distribution ratio of the operating drive torque and the driving drive torque close to an appropriate distribution ratio. Thus, the operating drive torque and the driving drive torque intended by the operator can be generated before exceeding the upper limit. For operators who find this structure easier to handle, work efficiency can be improved compared to the first embodiment.

[0169] Furthermore, in the fourth embodiment, when the operation amount of the accelerator pedal 58 is less than the maximum operation amount, the travel torque reaches the upper limit of the travel drive torque; or when the operation amount of the stick control lever 52 and the bucket control lever 53 is less than the maximum operation amount, the work torque reaches the upper limit of the work drive torque. Therefore, the frequency at which the operator depresses the accelerator pedal 58 to its maximum extent, or tilts the stick control lever 52 and the bucket control lever 53 until their operation amounts are at their maximum, can be reduced. As a result, the total amount of work required by the operator can be reduced, and the burden on the operator can be lessened.

[0170] <Fifth Implementation>

[0171] Main reference Figure 14 The wheeled loader 1 of the fifth embodiment will be described. Furthermore, in the figures, the same reference numerals are used for parts that are the same as or equivalent to those in the first embodiment, and the main differences are explained. Figure 14 Is with Figure 4 The same diagram is a functional block diagram of the main controller 500 in the fifth embodiment.

[0172] The main controller 500 of the fifth embodiment replaces the torque distribution ratio calculation unit 133 of the main controller 100 of the first embodiment, and has an upper limit value T that determines the operating drive torque. I_LIM and the upper limit of driving torque TC_LIM This is the function of the torque upper limit calculation unit 533.

[0173] Torque upper limit calculation unit 533 is based on reaction force F R Calculate the upper limit of torque T I_LIM T C_LIM The torque upper limit calculation unit 533, for example, refers to a predetermined upper limit value table and calculates based on the reaction force F. R upper limit of operating torque T I_LIM T C_LIM The upper limit value table is determined in advance through experiments and other means, and stored in ROM105.

[0174] The table of upper limits for driving torque is based on the reaction force F. R The larger the value, the higher the upper limit of the driving torque T. C_LIM The larger the characteristic, the better. Additionally, the upper limit of the driving torque is set as the reaction force F. R The larger the value, the higher the upper limit of the driving torque T. C_LIM The increase relative to the reaction force F R The smaller the rate of increase (slope), the better. The table of upper limits for the operating drive torque is based on the reaction force F. R The larger the value, the higher the upper limit of the operating drive torque T. I_LIM The smaller the characteristic, the better. Additionally, the upper limit of the operating drive torque is set as the reaction force F. R The larger the value, the higher the upper limit of the operating drive torque T. I_LIM The increase relative to the reaction force F R The greater the rate (slope) of the increase.

[0175] Engine torque distribution calculation unit 534 is based on the required torque T for operation. I_REQ and the upper limit value T of the operating drive torque determined by the upper limit value calculation unit 533 I_LIM The target torque T is determined using the above formula (5). I_TGT .

[0176] Engine torque distribution calculation unit 534 is based on driving requirement torque T C_REQ and the upper limit value T of the driving torque determined by the upper limit value calculation unit 533. C_LIM The target torque T is determined using the above formula (6). C_TGT .

[0177] Thus, the main controller 500 in the fifth embodiment is based on the upper limit value T of the operating drive torque. I_LIM and the upper limit of driving torque T C_LIM Controlling the operating drive torque and the driving drive torque, thereby enabling operation based on the reaction force F. RThis changes the distribution ratio of the operating drive torque and the driving drive torque. According to this fifth embodiment, the same effects as the fourth embodiment can be obtained.

[0178] The following variations are also within the scope of the present invention. The structures shown in the variations can be combined with the structures described in the above embodiments, or the structures described in the different embodiments described above can be combined with each other, or the structures described in the different variations below can be combined with each other.

[0179] <Variation Example 1>

[0180] Operation drive torque command T I_COM and driving torque command T C_COM The calculation method is not limited to the method described in the above embodiments. As a variation of the first embodiment, the engine torque distribution calculation unit 134 may also be based on the distribution ratio η calculated by the torque distribution ratio calculation unit 133. C η I Engine output torque TE, auxiliary machine required torque T AUX_REQ The required torque T for the operation I_REQ and the required torque T for driving C_REQ As explained below, the operation drive torque command T is calculated. I_COM and driving torque command T C_COM .

[0181] The engine torque distribution calculation unit 134 calculates the required operating torque T. I_REQ Required torque T for driving C_REQ And auxiliary equipment required torque T AUX_REQ The total required torque value T obtained by summing them up SUM_REQ (T SUM_REQ =T I_REQ +T C_REQ +T AUX_REQ ).

[0182] The engine torque distribution calculation unit 134 requires the total torque value T. SUM_REQ When the engine output torque TE is below a certain value, the required operating torque T will be... I_REQ The target torque T I_TGT The required torque T for driving C_REQ As the target torque for driving C_TGT .

[0183] The engine torque distribution calculation unit 134 requires the total torque value T. SUM_REQ When the torque is greater than the engine output torque TE, the required torque T is determined based on the torque distribution ratio η. I_REQ and the required torque T for drivingC_REQ Subtract the predetermined amount, and then calculate the target torque T. I_TGT and driving target torque T C_TGT The predetermined amount is the required total torque value T. SUM_REQ The difference ΔTE between the engine output torque TE and the torque distribution TE. In this case, the engine torque distribution calculation unit 134 adjusts the auxiliary engine required torque T. AUX_REQ Target torque T I_TGT and driving target torque T C_TGT The total target torque value T obtained by summing them up SUM_TGT It is equal to the engine output torque TE.

[0184] According to this variation, even when the excavation determination flag is set to open, the maximum values ​​of the driving force and the working force will not decrease. Therefore, work efficiency can be improved, and the wheel loader 1 can be made to operate further according to the operator's intention. According to this variation, similar to the first embodiment, work efficiency can be improved, and the maneuverability of the vehicle body can be further improved.

[0185] <Variation Example 2>

[0186] As a variation of the first embodiment, the engine torque distribution calculation unit 134 can also calculate the target torque T using equation (7). I_TGT The target torque T is calculated using equation (8). C_TGT .

[0187] [Formula 7]

[0188] T I_TGT =T I_REQ ·η I ·k…(7)

[0189] [Formula 8]

[0190] T C_TGT =T C_REQ ·η c ·k…(8)

[0191] k is a constant, pre-stored in ROM105. For example, when k is 1, the target torque T is... I_TGT To become the required torque T I_REQ The following values ​​represent the target torque T. C_TGT To become the required torque T for driving C_REQ The following values. For example, when k is set to 1, in η I =50%, η C When = 50%, the target torque T I_TGT To become the required torque T I_REQHalf of the value, the target torque T C_TGT To become the required torque T for driving C_REQ Half of the value. On the other hand, if k is greater than 1, the target torque T can be increased. I_TGT and the target torque T C_TGT Therefore, it can closely approximate the operating and driving forces intended by the operator. For example, when k is set to 2, in η I =50%, η C When = 50%, the target torque T I_TGT To become the required torque T I_REQ The value of the target torque T. C_TGT To become the required torque T for driving C_REQ The value of k. Additionally, the value of k can also be arbitrarily set by the operator through manual operation.

[0192] <Variation Example 3>

[0193] In reference Figure 10 In the second embodiment described, the reaction force F is calculated based on the time Tc after a predetermined time ΔTp elapsed from the moment T0 when the insertion flag is set to open. RC To determine the distribution ratio η of the operating drive torque. I and the distribution ratio η of driving torque. C For example, as a variation, the reaction force F can also be calculated sequentially after the insertion flag is set to on. R After the excavation judgment mark becomes open, the reaction force F R When the situation changes to a decrease, it will be based on the reaction force F at this time. R The determined distribution ratio η of the operating drive torque I and the distribution ratio η of driving torque. C Maintain this position until the excavation determination flag is closed. Therefore, similar to the second embodiment, in a single excavation operation, if the wheel loader 1 is moved forward and backward multiple times to scoop up sand, an appropriate torque distribution ratio η can be preset for subsequent sand scooping operations. I η C .

[0194] <Variation Example 4>

[0195] In the above embodiment, an example of the power generation inverter 41 and the travel inverter 42 being connected via a DC section 44 has been described, but the present invention is not limited thereto. The power generation inverter 41 and the travel inverter 42 may also be power conversion devices that do not pass through a DC section, such as a matrix converter.

[0196] <Variation Example 5>

[0197] In the above embodiment, a wheel loader 1 without an energy storage device connected to the DC unit 44 was described as an example, but the present invention is not limited thereto. The present invention can also be applied to wheel loaders with a structure that connects an energy storage device equipped with energy storage elements such as secondary batteries and capacitors to the DC unit 44 to control the voltage of the DC unit 44 or supply power.

[0198] <Variation Example 6>

[0199] In the above implementation, the traction force F is calculated based on equation (2). P Examples have been provided, but the invention is not limited thereto. For example, the bottom pressure Pa of the boom cylinder 4 and the traction force F P They are directly proportional. Therefore, the traction force F can also be calculated based on the bottom pressure Pa of the boom cylinder 4 detected by the pressure sensor 71. P Alternatively, an acceleration sensor can be installed on the wheel loader 1, and the traction force F can be calculated based on the acceleration detected by the acceleration sensor and the mass of the wheel loader 1. P .

[0200] <Variation Example 7>

[0201] The method for determining whether excavation work has begun is not limited to the method described in the above embodiments. For example, the reaction force F calculated by the reaction force calculation unit 131 can also be considered. R This is used to determine that excavation work has begun. For example, the excavation status determination unit 132 determines this when the bucket 3 is in the insertion posture angle range, the bottom pressure Pa of the boom cylinder 4 is above the pressure threshold Pa0, and the reaction force F... R If the predetermined reaction force threshold is exceeded, it is determined that excavation work has started. This reduces the occurrence of false determinations of an excavation state when no excavation work is being performed. Alternatively, instead of the determination method described in the above embodiment, it is possible to determine whether excavation work has started based on image data captured by a camera (image capture device) used to monitor the front of the wheel loader 1. It is also possible to determine whether excavation work has started based on information detected by an infrared sensor monitoring the front of the wheel loader 1.

[0202] <Variation Example 8>

[0203] In the above embodiment, an example was described where the excavation operation was determined to have ended when the bucket angle θ reached or exceeded the angle threshold θe after the excavation operation was determined to have started. However, the present invention is not limited to this. For example, the excavation operation may also be determined to have ended when a predetermined time threshold (e.g., about 5 seconds) has elapsed since the time from when the excavation operation was determined to have started. The time threshold is stored in advance in the ROM 105. The time threshold is determined in advance through experiments or the like.

[0204] <Variation Example 9>

[0205] In the first embodiment, the main controller 100 is described as follows: Figure 8 As shown, in step S160, based on the reference value η I 0, η C 0 determines the distribution ratio η of the operating drive torque. I and the distribution ratio η of driving torque C In step S170, the set value η is based on the torque distribution ratio setting dial 54. IS η CS The distribution ratio η of the working drive torque is determined. I and the distribution ratio η of driving torque C Examples.

[0206] However, in step S160, the main controller 100 may also base its decision on the set value η set by the torque distribution ratio setting dial 54. IS η CS To determine the distribution ratio η of the operating drive torque. I and the distribution ratio η of driving torque. C Additionally, in step S170, the main controller 100 may also base its decision on the reference value η. I 0, η C The distribution ratio η of the operating drive torque is determined by 0. I and the distribution ratio η of driving torque. C Furthermore, in both steps S160 and S170, based on the reference value η... I 0, η C 0 determines the allocation ratio η I η C In this case, the torque distribution ratio setting dial 54 can be omitted.

[0207] <Variation Example 10>

[0208] In the above embodiments, it is explained that the main controllers 100, 300, 400, and 500 calculate the reaction force F acting on the vehicle body 8 of the wheel loader 1. R And based on the calculated reaction force F RExamples of methods used to determine the torque distribution ratio and upper limit of torque are provided, but the invention is not limited to these. The main controller can also calculate the reaction force F acting on the wheel loader 1. R The physical quantities are related, and the torque distribution ratio and upper limit of torque are determined based on the calculated physical quantities. This is related to the reaction force F. R Physical quantities in a related relationship, such as the bottom pressure Pa of the boom cylinder 4, can be cited. This is based on the reaction force F... R When the torque distribution ratio and upper limit of torque are determined by the relevant physical quantities, it can be said that the main controller controls the working drive torque and the traveling drive torque based on the reaction force acting on the body 8 of the wheel loader 1. Therefore, the torque distribution ratio during excavation operations on a work site where the ground is inclined relative to the horizontal plane can be set to the same as the torque distribution ratio during excavation operations on a work site where the ground is parallel to the horizontal plane. That is, the effect of ground inclination can be reduced.

[0209] <Variation Example 11>

[0210] In the first embodiment, the reaction force F is calculated sequentially based on the vehicle speed v of the wheel loader 1. R The example illustrates this, but the reaction force F R The calculation method is not limited to this. Alternatively, the time-varying rate of vehicle speed v at the initial stage of penetration into the excavation object 91 can be compared with the time-varying rate of vehicle speed v pre-stored in ROM 105. If a match is found, the reaction force F can be determined based on the reaction force calculation data table stored in ROM 105. R The reaction force calculation data table is determined in advance for each time rate of change of multiple vehicle speeds v (i.e., for each of multiple vehicle speed change patterns) through experiments, etc.

[0211] <Variation Example 12>

[0212] In the above embodiments, in order to avoid interference and noise, the values ​​used for various judgments and calculations can also be processed by moving average or low-pass filtering.

[0213] <Variation Example 13>

[0214] The functions of the main controller described in the above embodiments can also be partially or fully implemented by hardware (e.g., by designing logic to execute each function through integrated circuits).

[0215] The embodiments of the present invention have been described above. However, the above embodiments only illustrate a portion of the application examples of the present invention and are not intended to limit the technical scope of the present invention to the specific structures of the above embodiments. The above embodiments and modifications are illustrated for ease of understanding of the present invention and are not limited to having all the structures described. In addition, a part of the structure of a certain embodiment or modification can be replaced with the structure of other embodiments or modifications, and it is also possible to add the structure of other embodiments or modifications to the structure of a certain embodiment or modification. Furthermore, the control lines and information lines shown in the figures show the parts that are deemed necessary for explanation and do not necessarily show all the control lines and information lines required on the product. In fact, it can be considered that almost all the structures are interconnected.

[0216] Explanation of reference numerals in the attached figures

[0217] 1…Wheel loader (operating vehicle), 2…Boom, 3…Bucket, 4…Boom cylinder (hydraulic cylinder), 5…Bucket cylinder (hydraulic cylinder), 6…Working device, 8…Car body, 11…Travel device, 20…Engine, 30A…Hydraulic pump, 40…Generator motor, 43…Travel motor (electric motor), 57…Mode switch (mode switching operation unit), 100, 300, 400, 500…Main controller (control device).

Claims

1. A work vehicle comprising: an engine mounted on a vehicle body; a hydraulic pump driven by the engine; a hydraulic cylinder that extends and retracts via hydraulic oil discharged from the hydraulic pump; a work device that moves according to the extension and retraction of the hydraulic cylinder; a travel device independently driven relative to the work device; an electric motor driven by electricity generated by the engine to actuate the travel device; and a control device that controls the hydraulic cylinder and the electric motor according to a first torque distribution ratio of the torque output by the engine that is consumed by the work device and a second torque distribution ratio of the torque output by the engine that is consumed by the travel device, characterized in that... The control device calculates the reaction force experienced by the vehicle body when it inserts into the excavation target, based on the vehicle's traction force and speed. During the excavation operation of the work vehicle, the control device determines the distribution ratio of the first torque and the distribution ratio of the second torque in the following manner: the greater the calculated reaction force on the vehicle body, the smaller the first torque becomes and the greater the second torque becomes; and the ratio of the increase in the distribution ratio of the second torque to the increase in the reaction force on the vehicle body becomes smaller. The control device controls the output of the hydraulic pump and the output of the electric motor based on the determined first torque distribution ratio and the second torque distribution ratio.

2. The working vehicle according to claim 1, characterized in that, The control device performs the following control: The upper limits of the first torque and the second torque are determined based on the reaction force; and The first torque and the second torque are controlled based on the upper limit values ​​of the first torque and the second torque.

3. The operating vehicle according to claim 1, characterized in that, The control device determines the distribution ratio of the first torque and the distribution ratio of the second torque based on the reaction force after a predetermined time has elapsed since the start of the excavation of the work vehicle. The control device controls the first torque and the second torque in a manner that maintains the distribution ratio of the first torque and the distribution ratio of the second torque until the end of the excavation operation.

4. The working vehicle according to claim 1, characterized in that, The working device has a boom mounted on the vehicle body and a bucket mounted on the boom. The control device controls the second torque in such a way that the greater the pressure of the hydraulic cylinder that actuates the boom, the smaller the second torque becomes.

5. The operating vehicle according to claim 1, characterized in that, The work vehicle also includes a mode switching operation unit, which can manually switch between a first control mode and a second control mode. The first control mode is a mode that controls the first torque and the second torque based on the reaction force, and the second control mode is a mode that controls the first torque and the second torque independently of the reaction force to keep the ratio of the first torque and the second torque at a predetermined ratio.

Images