Work vehicle

Abstract

The work vehicle (1) has a main controller (100) that controls travel driving force and work driving force. The main controller (100) has: a travel residual time calculation section (111) that calculates a residual time until a target raising operation distance is reached as a travel residual time (t C ); a work residual time calculation section (112) that calculates a residual time until a target boom angle is reached as a work residual time (t I ); a raising operation determination section (113) that determines whether or not a state in which raising operation is being performed; a correction rate setting section (114) that sets a travel correction rate (η C ) that adjusts travel driving torque and a work correction rate (η I ) that adjusts work driving torque in accordance with the travel residual time (t C ), the work residual time (t I ), and a raising operation determination flag; and an engine torque distribution calculation section (115) that calculates a travel driving torque command and a work driving torque command in accordance with the travel correction rate (η C ) and the work correction rate (η I ).

Description

Technical Field

[0001] This invention relates to work vehicles such as wheel loaders used for loading operations.

[0002] This application claims priority based on Japanese Application No. 2021-049604, filed on March 24, 2021, the contents of which are incorporated herein by reference. Background Technology

[0003] As a work vehicle, a wheel loader is known to have a travel device for moving the vehicle body and a work device for digging sand, soil, etc., including a bucket and a boom. When such a work vehicle digs sand, soil, etc., and loads it into the bucket to pile onto a dump truck or other loading object, a movement called lifting operation is performed, in which the vehicle body moves forward to the loading object while the boom is raised. This lifting operation requires operation of the boom control lever, accelerator pedal, and brake pedal, which is complex and therefore places a heavy burden on the operator. In addition, if the operation is performed by quickly moving forward to the loading object and raising the boom to the required height before reaching the loading object, both the efficiency of the handling operation and fuel efficiency are improved, thus allowing the operator to perform precise operation according to the situation.

[0004] For example, Patent Document 1 discloses a work vehicle that controls the transmission torque from the power generation device to the drive wheel so that the difference between a first ratio and a second ratio is 0. The first ratio is the ratio of a value corresponding to the target travel distance of the vehicle body to the position where the excavated material is discharged after the bucket has made an excavation to a value corresponding to the target rise of the boom after the start of forward movement. The second ratio is the ratio of a value corresponding to the actual travel distance after the start of forward movement to a value corresponding to the actual rise of the boom after the start of forward movement.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: International Publication No. 2015 / 083753 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] In the work vehicle described in Patent Document 1, during the operation accompanied by lifting, the driving force is controlled to maintain the ratio of the target travel distance to the target lifting amount. Therefore, if the bucket height is high at the start of the lifting operation and the road surface is sloping upwards towards the loading object, the travel device is not controlled. Consequently, the target lifting amount will be reached before the target travel distance is reached, potentially leading to reduced efficiency and fuel efficiency in the handling operation. To mitigate this reduction in efficiency and fuel efficiency, the operator needs to perform complex and precise operations by adjusting the stick control lever and accelerator pedal during the lifting operation to raise the stick to the required height before loading the object. Therefore, the operator's workload remains high.

[0010] This invention was made to solve such a technical problem, and its purpose is to provide a work vehicle that can reduce the workload of the operator during loading operations.

[0011] Methods for solving problems

[0012] The work vehicle of the present invention comprises: a traveling device for driving the vehicle body; a prime mover for supplying driving force to the traveling device; a work device disposed on the vehicle body and having a boom rotatable in a vertical direction; a work prime mover for supplying work driving force to the work device; a traveling state detection device for detecting the traveling state of the vehicle body including vehicle speed and traveling distance; a work state detection device for detecting the work state of the work device including the angle of the boom; and a control device for controlling the traveling prime mover and the work prime mover, characterized in that the control device controls the traveling state of the vehicle body detected by the traveling state detection device and the work state detected by the work state detection device. The operating status of the working device is measured, and it is determined whether the specific conditions for the lifting of the boom during the forward movement of the vehicle body are met during loading operations. If the specific conditions are met, a driving correction rate for adjusting the driving force and a working correction rate for adjusting the working driving force are set based on the vehicle speed and driving distance detected by the driving status detection device, the boom angle detected by the working status detection device, a preset target driving distance, and a preset target boom angle. The driving force of the driving prime mover and the working driving force of the working prime mover are controlled based on the set driving correction rate and working correction rate.

[0013] In the work vehicle of the present invention, the control device sets a driving correction rate and a work correction rate based on the vehicle speed and travel distance detected by the driving status detection device, the boom angle detected by the work status detection device, a preset target travel distance, and a preset target boom angle. Based on the set driving correction rate and work correction rate, the control device controls the driving force of the driving prime mover and the work driving force of the work prime mover. Therefore, it is possible to balance the driving force and work driving force while synchronizing the completion time of forward travel with the completion time of boom raising, thus reducing the operator's workload. Furthermore, this shortens the loading operation time, improving both loading operation efficiency and fuel efficiency.

[0014] Invention Effects

[0015] According to the present invention, the workload of operators during loading operations can be reduced. Attached Figure Description

[0016] Figure 1 This is a side view of the work vehicle according to the first embodiment.

[0017] Figure 2 This is a system structure diagram showing the work vehicle of the first embodiment.

[0018] Figure 3 This diagram illustrates the basic handling operations of work vehicles.

[0019] Figure 4 It is a diagram used to illustrate the operation that accompanies the upward movement.

[0020] Figure 5 This is a block diagram representing the main controller of the work vehicle.

[0021] Figure 6 This is a diagram used to illustrate the angle of the bucket.

[0022] Figure 7 This is a diagram showing an example of a table that displays the set correction rate.

[0023] Figure 8A It is a graph showing the relationship between the lever operation amount and the pump's required flow rate.

[0024] Figure 8B This is a graph showing the relationship between the rotational speed of the motor and the required torque for driving.

[0025] Figure 9 This is a flowchart representing the control processing of the main controller.

[0026] Figure 10 This is a diagram used to illustrate the effect of the work vehicle of the first embodiment (comparison with the comparative example).

[0027] Figure 11 This is a diagram used to illustrate the effect of the work vehicle of the second embodiment (comparison with the comparative example).

[0028] Figure 12 This is a block diagram showing the main controller of the work vehicle in the third embodiment. Detailed Implementation

[0029] Hereinafter, embodiments of the work vehicle of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same reference numerals are used to denote the same elements, and repeated descriptions are omitted. Furthermore, in the following description, an example of a wheeled loader is given, but the work vehicle of the present invention is not limited to a wheeled loader and may also be a forklift, a lift truck, a telescopic forklift, etc. In addition, in the following description, an example using a hybrid power system with an engine and a generator-motor as drive sources is given, but a system using only an engine may also be used. Furthermore, in the following description, the directions and positions of up / down, left / right, and front / back are based on the normal operating state of the work vehicle, i.e., the state in which the wheels are in contact with the ground.

[0030] [First Implementation Method]

[0031] Figure 1 This is a side view showing the work vehicle according to the first embodiment. (Example) Figure 1 As shown, the work vehicle 1 in this embodiment is, for example, an electrically driven wheel loader, having a body 8 equipped with an electric travel device 11 and a multi-joint type work device 6 located 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 central connecting part 8C connecting the front body 8A and the rear body 8B. The aforementioned work device 6 is installed on the front body 8A, and a cab 12 and an engine compartment 16 are arranged on the rear body 8B. In addition, the cab 12 is provided with various operating parts (51-58) for the operator to operate the work vehicle 1, and the engine compartment 16 houses the engine 20, hydraulic pumps 30A, 30B, 30C, and valves, etc. (see reference). Figure 2 ).

[0032] The working device 6 includes a pair of left and right booms (also called lifting booms) 2 that are rotatably mounted on the front of the vehicle body 8A in the vertical direction, and a bucket 3 that is connected to the front end of the booms 2 and mounted in a manner that allows rotation in the vertical direction. In this embodiment, a Z-link type (double-arm crank type) linkage mechanism is adopted as the linkage mechanism for operating the bucket 3.

[0033] Figure 2This is a system structure diagram illustrating the work vehicle of the first embodiment. For example... Figure 2 As shown, the work vehicle 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 and the generator motor 40, a boom cylinder 4 and a bucket cylinder 5 driven by working oil discharged from the hydraulic pump 30A, a front control unit 31 controlling the working oil discharged from the hydraulic pump 30A, a brake cylinder 17 and a parking brake cylinder 18 driven by working oil discharged from the hydraulic pump 30B, a brake control unit 32 controlling the working oil discharged from the hydraulic pump 30B, a steering cylinder 15 driven by working oil discharged from the hydraulic pump 30C, a steering control unit 33 controlling the working oil discharged from the hydraulic pump 30C, and the aforementioned travel device 11 driven by electricity generated by the generator motor 40.

[0034] Engine 20 is a prime mover, consisting of an internal combustion engine such as a diesel engine. The generator motor 40 rotates by the torque output from engine 20.

[0035] 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, hydraulic pumps 30A, 30B, and 30C are driven by the torque output from engine 20 and generator motor 40.

[0036] The working oil discharged from the hydraulic pump 30A is supplied to the boom cylinder 4 and bucket cylinder 5 via the front control unit 31. The front control unit 31 controls the extension and retraction of the boom cylinder 4 and bucket cylinder 5 by controlling the pressure, speed and flow direction of the working oil discharged from the hydraulic pump 30A.

[0037] The boom cylinder 4 is a hydraulic cylinder that extends and retracts using working oil supplied from the hydraulic pump 30A, causing the boom 2 to rotate vertically. The boom cylinders 4 are arranged in a pair, corresponding to a pair of left and right booms 2. The bucket cylinder 5 is a hydraulic cylinder that extends and retracts using working oil supplied from the hydraulic pump 30A, causing the bucket 3 to rotate vertically. In this embodiment, the hydraulic pump 30A serves as the prime mover supplying the working device 6 with the driving force for operation.

[0038] The working oil discharged from the hydraulic pump 30B is supplied to the brake cylinder 17 and the parking brake cylinder 18 via the brake control unit 32. The brake control unit 32 controls the extension and retraction of the brake cylinder 17 and the parking brake cylinder 18 by controlling the pressure, speed and flow direction of the working oil discharged from the hydraulic pump 30B.

[0039] Working oil discharged from hydraulic pump 30C is supplied to steering cylinder 15 via steering control unit 33. Steering control unit 33 controls the extension and retraction of steering cylinder 15 by controlling the pressure, speed and flow direction of working oil discharged from hydraulic pump 30C. Steering cylinder 15 is composed of hydraulic cylinders, a pair of left and right cylinders, and is configured to connect the front body 8A and the rear body 8B.

[0040] The traveling device 11 includes: a front wheel 7A (wheel 7) mounted on the front of the vehicle body 8A, a rear wheel 7B (wheel 7) mounted on the rear of the vehicle body 8B, and a power transmission device that transmits power from the traveling motor 43 to the wheels 7. The wheels 7 rotate under the drive of the traveling motor 43, causing the working vehicle 1 to move forward and backward. The power transmission device may include, for example, an axle, a differential, a drive shaft, etc.

[0041] The drive motor 43 constitutes a secondary prime mover, rotating by receiving electricity generated by the generator motor 40. Furthermore, in this embodiment, the generator motor 40 and the drive motor 43 constitute a drive prime mover that supplies driving force to the driving device 11.

[0042] In addition, the work vehicle 1 also includes: a main controller (control device) 100, which controls the vehicle as a whole; an inverter 41 for the generator motor, which controls the generator motor 40 according to the generator voltage command from the main controller 100; an inverter 42 for the travel motor, which controls the torque of the travel motor 43 according to the travel drive torque command from the main controller 100; and various operating components (51 to 58), which are installed in the cab 12.

[0043] The cab 12 is equipped with: a forward / reverse switch 51, which switches the forward (F) and reverse (R) movement of the vehicle body 8; a stick control lever 52, which is used to operate the stick 2; a bucket control lever 53, which is used to operate the bucket 3; a mode switch (mode switching device) 54, which switches between automatic and manual modes; a steering wheel 55, which is used to indicate the left and right directions of travel of the vehicle body 8; a parking brake switch 56, which is used to activate the parking brake; an accelerator pedal 58, which is used to accelerate the vehicle body 8; and a brake pedal 57, which is used to decelerate the vehicle body 8.

[0044] Furthermore, if the stick control lever 52 is operated, the stick 2 will rotate vertically (pitch motion) through the extension and retraction of the stick cylinder 4. If the bucket control lever 53 is operated, the bucket 3 will rotate vertically (push or dump) through the extension and retraction of the bucket cylinder 5.

[0045] If the steering wheel 55 is operated, the front body 8A will bend to the left or right relative to the rear body 8B with the central connecting part 8C as the center (steering).

[0046] When the forward / reverse switch 51 is operated to the forward (F) side, if the accelerator pedal 58 is pressed, the wheels 7 rotate in the forward direction, and the vehicle body 8 moves forward. On the other hand, when the forward / reverse switch 51 is operated to the reverse (R) side, if the accelerator pedal 58 is pressed, the wheels 7 rotate in the reverse direction, and the vehicle body 8 moves backward.

[0047] The mode switch 54 is a switch that allows manual switching between automatic and manual modes. Automatic mode is the execution mode for setting the driving correction rate and work correction rate (described later). In other words, it controls the amount of pressure applied to the accelerator pedal 58 and the amount of operation of the stick stalk 52 based on the speed of the work vehicle 1 and the stick angle (angle of the stick 2). Conversely, manual mode is the prohibited mode for setting and executing the driving correction rate and work correction rate. In other words, it is the mode for not controlling the amount of pressure applied to the accelerator pedal 58 and the amount of operation of the stick stalk 52 based on the vehicle speed and stick angle.

[0048] That is, the mode switch 54 has an automatic mode position and a manual mode position. When the mode switch 54 is operated to the automatic mode position, it is set to automatic mode, and therefore outputs a signal to the main controller 100 indicating that it is set to automatic mode. Similarly, when the mode switch 54 is operated to the manual mode position, it is set to manual mode, and therefore outputs a signal to the main controller 100 indicating that it is set to manual mode.

[0049] The main controller 100 comprises a microcomputer having a CPU (Central Processing Unit) 101 as the operating circuit, a ROM (Read Only Memory) 102 and RAM (Random Access Memory) 103 as storage devices, an input interface 104, an output interface 105, and other peripheral circuits. Furthermore, the main controller 100 can be composed of a single microcomputer or multiple microcomputers.

[0050] The ROM 102 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 102 of the main controller 100 is a storage medium capable of reading programs that implement the functions of this embodiment. The RAM 103 is a volatile memory, a working memory that directly inputs and outputs data with the CPU 101. The RAM 103 temporarily stores necessary data during the execution of the program by the CPU 101. Furthermore, the main controller 100 may also include storage devices such as flash memory or hard disk drives.

[0051] CPU 101 is a processing device that expands and executes the program stored in ROM 102 in RAM 103, and performs prescribed operations on the signals received from input interface 104, ROM 102, and RAM 103 according to the program.

[0052] Operation signals from various operating components and sensor signals from various sensors are input to the input interface 104. The input interface 104 converts the input signals into signals that can be processed by the CPU 101. The output interface 105 generates an output signal corresponding to the calculation result in the CPU 101 and outputs the signal to the forward control unit 31, the braking control unit 32, the steering control unit 33, the inverter 41 for the generator motor, and the inverter 42 for the drive motor, etc.

[0053] The main controller 100 controls the front control unit 31, the braking control unit 32, the steering control unit 33, the inverter 41 for the generator motor, and the inverter 42 for the travel motor in a unified manner based on the operation signals input by the operator and the sensor signals detected by various sensors.

[0054] 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 57 indicating the amount of operation of the brake pedal 57, 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 is a mode switching signal output from the mode switch 54 indicating the operating position of the mode switch 54.

[0055] Furthermore, 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 (operating status detection device) 62 is, for example, a potentiometer that 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 the main controller 100. Since the angle of the vehicle body 8 relative to the ground (driving surface) is constant, 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. The bucket relative angle sensor (operating status detection device) 63 is, for example, a potentiometer that detects the relative angle (tilt angle) of the bucket 3 relative to the stick 2, and outputs a signal indicating the detected angle to the main controller 100.

[0056] 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 (driving state detection device) 61 detects the speed of the working vehicle 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 drive motor 43 detected by multiple rotational speed sensors, and signals indicating the discharge pressure of hydraulic pumps 30A, 30B, 30C and the pressure (load pressure) of hydraulic cylinders detected by multiple pressure sensors.

[0057] The main controller 100 outputs forward control commands to the forward control unit 31 based on the operating direction and amount of the stick operating lever 52 and the operating direction and amount of the bucket operating lever 53. As described above, the forward control unit 31 adjusts the pressure, speed, and flow direction of the working oil discharged from the hydraulic pump 30A according to the forward control commands from the main controller 100, thereby actuating the stick cylinder 4 and the bucket cylinder 5. The forward control unit 31 includes a directional control valve for controlling the flow of the working oil discharged from the hydraulic pump 30A, and a solenoid valve for generating pilot pressure input to the pilot chamber of the directional control valve.

[0058] The main controller 100 outputs braking control commands to the brake control unit 32 based on the operation amount of the brake pedal 57 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 brake cylinder 17 (for activating the brake) and the parking brake cylinder 18 (for activating the parking brake). The brake control unit 32 includes a directional control valve for controlling the flow of the working oil discharged from the hydraulic pump 30B, and a solenoid valve for generating pilot pressure input to the pilot chamber of the directional control valve.

[0059] The main controller 100 outputs steering control commands to the steering control unit 33 based on the operating direction and amount of the steering wheel 55. The steering control unit 33 adjusts the pressure, speed, and direction of the working oil discharged from the hydraulic pump 30C according to the steering control commands from the main controller 100, 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.

[0060] The inverter 41 for the generator motor and the inverter 42 for the travel motor are connected via a DC bus 44. Furthermore, the work vehicle 1 in this embodiment does not have an energy storage device connected to the DC bus 44. The inverter 41 for the generator motor controls the bus voltage of the DC bus 44 using power supplied from the generator motor 40, according to a generation voltage command from the main controller 100. The inverter 42 for the travel motor drives the travel motor 43 using power from the DC bus 44, according to a travel drive torque command from the main controller 100.

[0061] Here, refer to Figure 3 and Figure 4 The process of completing this invention will be described.

[0062] Figure 3 This diagram illustrates the basic handling operations of a work vehicle. Figure 4 This diagram illustrates the operation accompanying the upward movement. In the material handling operation, the work vehicle 1 excavates sand, minerals, etc. (materials to be handled) and loads them onto a dump truck or similar loading object 92. Figure 3 This refers to a V-shaped loading method used in carrying out the transport operation.

[0063] Specifically, the work vehicle 1 first as follows Figure 3As indicated by arrow X1, the vehicle moves towards the excavation target 91, such as a hill. Next, the work vehicle 1 inserts its bucket 3 into the excavation target 91, and operates the boom 2 and bucket 3 to load sand, minerals, or other materials into the bucket 3. Then, the work vehicle 1 scoops the bucket 3 forward (performing a pushing action) in a manner that prevents the loaded material from spilling. Thus, the excavation operation is completed. After the excavation operation is completed, the work vehicle 1... Figure 3 As indicated by arrow X2, temporarily retreat. Then, as... Figure 3 As indicated by arrow Y1, the work vehicle 1 moves toward the loading object 92.

[0064] At this time, as Figure 4 As shown, the operator of the work vehicle 1 raises the boom 2 by operating the boom control lever 52, and moves the vehicle body 8 (i.e., work vehicle 1) towards the load 92 by operating the steering wheel 55 and the accelerator pedal 58. Then, the vehicle body 8 is brought to a stop near the load 92. Figure 3 In the diagram, the work vehicle 1, which is stopped near the loaded object 92, is represented by a dashed line.

[0065] Next, the operator operates the bucket control lever 53 to tilt the bucket 3, thereby loading the material inside the bucket 3 into the cargo box of the loading object 92 (i.e., unloading the material from the bucket 3). Thus, the loading operation is completed. Furthermore, Figure 4 The series of operations shown is referred to as the aforementioned "operations accompanying the lifting operation," and the distance traveled by the work vehicle 1 when the boom 2 is raised to the required unloading height during the lifting operation is called the "lifting distance." After the lifting operation, as... Figure 3 As shown by arrow Y2, the work vehicle 1 reverses again and returns to its original position.

[0066] This series of operations, which includes both digging and loading, is called "V-shaped loading" and accounts for the majority of the total operating time of the work vehicle 1. Therefore, reducing the workload of this series of operations is effective in alleviating the operator's burden. Here, workload refers to the number of times the operator changes the amount of operation of operating components such as the accelerator pedal 58 and the boom lever 52 during the series of operations that include digging and loading. The fewer the number of operations, the less the operator's burden.

[0067] During loading operations, the operator operates the boom control lever 52 to its maximum (full boom) and the accelerator pedal 58 to its maximum (full acceleration) at the start of the lifting motion. With the boom fully extended and fully accelerated, the operator raises the boom angle to the required unloading height near the load 92. This is a loading operation that is less strenuous for the operator and offers good work efficiency and fuel efficiency. Hereinafter, this operation will be referred to as "operation accompanying simplified lifting."

[0068] However, as mentioned above, when the bucket height is high at the start of the lifting operation or when the road surface slopes upwards towards the load 92, if a simple lifting operation is performed, the driving force of the travel device 11 (travel driving force) is insufficient, while the driving force of the working device 6 (working driving force) is excessive, causing the boom 2 to be lifted in front of the load 92. That is, the lifting distance becomes shorter. At this time, when moving closer to the load 92 after the working device 6 operation is completed, the time spent operating only the travel device 11 becomes longer, reducing work efficiency and fuel efficiency. To prevent this, the operator needs to release the boom operating lever 52 during the lifting operation to continuously maintain a balance between travel driving force and working driving force by lifting the boom 2 in front of the load 92. Therefore, the operator's workload increases.

[0069] Therefore, the inventors of this application have conducted repeated and in-depth research and found that when the operator performs the operation of simple upward movement, the balance between the driving force required to lift the boom 2 near the loaded object 92 and the working driving force is appropriate, thereby reducing the burden on the operator.

[0070] Furthermore, the appropriate balance between the driving force and the working force varies depending on the travel distance, stick angle, vehicle speed, and stick angular velocity of the working vehicle 1. At any given moment during the lifting operation, the faster the stick angular velocity relative to the vehicle speed, the more necessary it is to suppress the working force. Conversely, at any given moment during the lifting operation, the faster the vehicle speed relative to the stick angular velocity, the more necessary it is to suppress the driving force. In this embodiment, during loading operations, the balance between the driving force and the working force is adjusted based on the travel distance, stick angle, vehicle speed, and stick angular velocity of the working vehicle 1, thereby reducing the operator's workload.

[0071] Therefore, as Figure 5 As shown, the main controller 100 of this embodiment includes a remaining driving time calculation unit 111, which calculates the remaining time until the vehicle body 8 (i.e., the work vehicle 1) reaches the target upward travel distance (target travel distance) as the remaining driving time t. C The remaining time calculation unit 112 calculates the remaining time until the stick 2 reaches the target stick angle as the remaining time t of the operation. I The lifting operation determination unit 113 determines whether the work vehicle 1 is in a lifting operation state during loading operations; the correction rate setting unit 114 determines the remaining driving time t calculated by the remaining driving time calculation unit 111. C The remaining time t of the task calculated by the remaining task time calculation unit 112 IThe rising operation determination flag determined by the rising operation determination unit 113 is used to set the driving correction rate η for adjusting the driving torque. C and the work correction rate η used to adjust the work drive torque I ; and the engine torque distribution calculation unit 115, which calculates the driving correction rate η set by the correction rate setting unit 114. C and job correction rate η I Calculate the driving torque command used to control the driving torque and the work torque command used to control the work torque.

[0072] The remaining travel time calculation unit 111 calculates the remaining travel time t based on the travel distance and speed of the work vehicle 1. C Remaining travel time t C For example, it can be calculated using the following mathematical formula (1).

[0073] [Mathematical Expression 1]

[0074]

[0075] In mathematical formula (1), d RR d1 is the target upward travel distance, d1 is the travel distance at time t1 after a predetermined time elapsed from the start time t0 of the upward travel, and v1 is the speed of the work vehicle 1 at time t1. The target upward travel distance is preset based on empirical values, for example, the operator sets the target upward travel distance based on past experience and inputs the set target upward travel distance into the main controller 100. The speed of the work vehicle 1 is detected by the speed sensor 61. In addition, the speed of the work vehicle 1 can also be calculated based on information detected by a rotary encoder (driving status detection device) that detects the rotational speed of the shaft constituting the power transmission device. On the other hand, the travel distance can be calculated based on the rotational speed and rotational speed of the travel motor 43, or based on the speed and travel time detected by the speed sensor 61.

[0076] The remaining operation time calculation unit 112 calculates the remaining operation time t based on the stick angle and stick angular velocity of the working vehicle 1. I Remaining time for the assignment (t) I For example, it can be calculated using the following mathematical formula (2).

[0077] [Mathematical Expression 2]

[0078]

[0079] In mathematical expression (2), θ RR Let θ1 be the target stick angle, and v be the stick angle at time t1 after a specified time elapsed from the start of the ascent. θ1Let t1 be the stick angular velocity of the working vehicle 1. The target stick angle is preset based on the height of the cargo box of the loaded object 92. The stick angle is detected by the stick relative angle sensor 62. Based on the stick angle detected by the stick relative angle sensor 62, the stick angular velocity is calculated by the main controller 100.

[0080] The lifting operation determination unit 113 determines whether the specific conditions for raising the boom 2 during loading operations are met based on the driving state of the vehicle body 8 and the operating state of the working device 6 detected by sensors. In this embodiment, the lifting operation determination unit 113 determines whether the working vehicle 1 is in a lifting operation state based on the operation state of the accelerator pedal 58 detected by sensors and the states of the boom 2 and bucket 3 detected by sensors. More specifically, the lifting operation determination unit 113 determines whether the working vehicle 1 is in a lifting operation state based on the bucket angle θ, the amount of operation of the accelerator pedal 58, and the amount of operation of the boom control lever 52.

[0081] Figure 6 This is a diagram used to illustrate the angle of the bucket. For example... Figure 6 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 pushing action, the bucket angle θ increases with the rotation. In other words, if the bucket 3 rotates by a dumping action, the bucket angle θ decreases with the 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.

[0082] When the bucket angle θ is a predetermined first angle threshold θ a When the operation of the accelerator pedal 58 and the boom control lever 52 increases, the lifting operation determination unit 113 determines that lifting operation has started and sets the lifting operation determination flag to "on". Regarding the lifting operation determination flag, it is set to "on" when the work vehicle 1 is in a lifting operation state and to "off" when the lifting operation ends.

[0083] First angle threshold θ a This is a threshold used to determine the start of the upward movement, set according to the scooping posture of the working device 6, and pre-stored in the ROM 102 of the main controller 100. The scooping posture of the working device 6 is the posture in which the upper surface of the bucket 3 is approximately parallel to the ground.

[0084] Furthermore, after determining that upward movement has begun, the upward movement determination unit 113, when the bucket angle θ is at the second angle threshold θ... b When the temperature is below 0° (for example, around 0°), the ascent operation is considered to have ended, and the ascent operation determination flag is set to off.

[0085] Second angle threshold θ b This is a threshold used to determine whether the lifting operation has ended after it has started. For example, the bucket angle θ is the value at which the bucket 3 can be completed by the dumping action and the bucket 3 is in an unloading posture. That is, if the lifting operation determination unit 113 detects that the bucket 3 is in an unloading posture after determining that the lifting operation has started, it determines that the lifting operation has ended. In addition, the lifting operation can also be determined to have ended when the operation amount of the accelerator pedal 58 and the stick control lever 52 is 0.

[0086] When the mode switch 54 is set to automatic mode, the correction rate setting unit 114 calculates the remaining driving time t by the remaining driving time calculation unit 111. C The remaining time t of the task calculated by the remaining task time calculation unit 112 I The driving correction rate η is set by the upward driving determination flag determined by the upward driving determination unit 113. C and job correction rate η I Driving correction rate η C and job correction rate η I Take values ​​from 0% to 100%.

[0087] Specifically, the correction rate setting unit 114 first uses the remaining driving time t calculated by the remaining driving time calculation unit 111. C and the remaining time t of the task calculated by the remaining task time calculation unit 112 I The remaining time difference Δt is calculated as shown in the following mathematical formula (3). C-I .

[0088] [Mathematical Expression 3]

[0089] Δt C-I =t C -t I ···(3)

[0090] Next, the correction rate setting unit 114 sets the correction rate based on the calculated remaining time difference Δt. C-I And pre-made correction rate charts to set the driving correction rate η C and job correction rate η I . Figure 7 It is used to set the driving correction rate η C and job correction rate η I An example of a correction rate chart. Figure 7 In the diagram, the dashed line represents the remaining time difference Δt. C-I With driving correction rate η C In the corresponding chart, the solid line represents the remaining time difference Δt. C-I With the work correction rate η I The corresponding charts.

[0091] Figure 7 The correction rate chart shown is pre-created based on experimental data, etc., and is pre-stored in the ROM102 of the main controller 100. For example... Figure 7 As shown, the remaining time difference Δt C-I The larger the value, the higher the job correction rate η. I The larger the remaining time difference Δt is, the greater the difference. C-I The smaller the value, the higher the driving correction rate η. C The larger. Thus, when the loading operation of work vehicle 1 involves a simple upward movement, compared to the remaining travel time t... C Compared to the remaining time t for the assignment I The shorter the length, the higher the job correction rate η. I The larger the value, the faster the operating drive torque (operating drive force) can be reduced. As a result, the lifting speed of boom 2 is significantly limited. On the other hand, with the remaining travel time t... C Compared to the remaining time t for the assignment I The longer the length, the higher the driving correction rate η. C The larger the torque, the faster the driving torque (driving force) can be reduced. As a result, the speed of the work vehicle 1 is significantly limited.

[0092] Furthermore, during the operation accompanying the ascent, the remaining travel time t is calculated by the remaining travel time calculation unit 111. C and the remaining time t of the task calculated by the remaining task time calculation unit 112 I The change, therefore, depends on the remaining travel time t. C and the remaining time t for the task I Set driving correction rate η C and the work correction rate η I It also changes.

[0093] On the other hand, when the mode switch 54 is set to manual mode, the correction rate setting unit 114 prohibits the driving correction rate η. C and the work correction rate η I The settings are executed. In this case, the driving correction rate η will be... C and the work correction rate η I Keep it at a constant value (e.g., around 0%).

[0094] The engine torque distribution calculation unit 115 calculates the torque distribution based on the correction rate η set by the correction rate setting unit 114. C η I Engine output torque T E Auxiliary machine requires torque T AUX_REQ The required torque T for the operation I_REQ and the required torque T for driving C_REQ Calculate the driving torque command T for the operation. I_COM and driving torque command T C_COM .

[0095] Engine output torque T E Auxiliary machine requires 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 T is calculated separately by the main controller 100. E This is the maximum torque that can be output at the current engine rotation speed. The main controller 100, for example, refers to the engine output torque curve stored in ROM 102 and calculates the engine output torque T based on the engine rotation speed detected by the engine rotation speed sensor. E .

[0096] Auxiliary machine requires torque T AUX_REQ The calculation is based on the operating states of multiple auxiliary machines that operate using electricity generated by the generator motor 40. The main controller 100 sets a target value for the engine rotation speed (e.g., 1800 rpm). The target value for the engine rotation speed set by the main controller 100 is output to the engine controller (not shown). The engine controller controls the fuel injection device (not shown) to make the engine rotation speed detected by the engine rotation speed sensor the target value.

[0097] In addition, the main controller 100 calculates the required torque T based on the operation amount of the boom control lever 52 and the operation amount of the bucket control lever 53. I_REQ . Figure 8A This is an example of a pump demand map that represents the relationship between lever operation and pump required flow rate. This pump demand map is pre-stored in the ROM 102 of the main controller 100. The main controller 100 first refers to... Figure 8A 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; the greater the lever operation amount, the greater the 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] Next, the main controller 100 calculates the required hydraulic power 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 operating torque T based on the calculated required hydraulic power and the rotational speed of the engine 20 detected by the rotational speed sensor. I_REQ The greater the lever operation, the higher the required torque T. I_REQ The larger.

[0099] In addition, the main controller 100 calculates the required driving torque T based on the rotational speed of the drive motor 43 and the operation amount (acceleration signal) of the accelerator pedal 58. C_REQ . Figure 8B This is an example of a torque mapping for the drive motor 43, representing the relationship between the rotational speed of the drive motor and the required driving torque. This torque mapping is pre-stored in the ROM 102 of the main controller 100. The ROM 102 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 rotation speed of the driving motor 43, and the higher the required torque T for driving. C_REQ The smaller.

[0100] In addition, the main controller 100 selects a torque map (torque curve) corresponding to the magnitude of the acceleration signal (the magnitude of the operation amount of the accelerator pedal 58), and calculates the required driving torque T based on the rotational speed of the drive motor 43. C_REQ For example, when the accelerator pedal 58 is fully engaged (when the acceleration signal is at its maximum), the solid line torque mapping is selected (refer to...). Figure 8B The main controller 100, referring to the selected torque mapping, calculates the required driving torque T based on the rotational speed of the driving motor 43. 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] Furthermore, the engine torque distribution calculation unit 115 first calculates the required operating torque T based on the operating torque T calculated by the main controller 100. I_REQ The correction rate η of the operating drive torque set by the correction rate setting unit 114 I Calculate the target torque T for the task. I_TGT Target torque T I_TGT For example, it can be calculated using mathematical formula (4).

[0102] [Mathematical Expression 4]

[0103] T I_TGT =T I_REQ ×(1-η I(4)

[0104] In addition, the engine torque distribution calculation unit 115 calculates the required driving torque T by the main controller 100. C_REQ The correction rate η of the driving torque set by the correction rate setting unit 114 C Calculate the target torque T. C_TGT Target torque T C_TGT Calculated using mathematical formula (5).

[0105] [Mathematical Expression 5]

[0106] T C_TGT =T C_REQ ×(1-η C (5)

[0107] Next, the engine torque distribution calculation unit 115 calculates the target torque T for the operation. I_TGT Target torque T C_TGT Auxiliary machine requires torque T AUX_REQ The total target torque T obtained by summing them up SUM_TGT (T SUM_TGT =T I_TGT +T C_TGT +T AUX_REQ Furthermore, at the target total torque value T SUM_TGT Engine output torque T E In the following cases, the engine torque distribution calculation unit 115 will calculate the target torque T. I_TGT The driving torque command T is determined to be the work drive torque. I_COM The target torque T will be used for driving. C_TGT The driving torque command T is determined. C_COM .

[0108] On the other hand, at the target total torque value T SUM_TGT Compared to engine output torque T E In large cases, the engine torque distribution calculation unit 115 determines the operating drive torque command T. I_COM and driving torque command T C_COM This causes the work drive torque command T to be applied. I_COM Driving torque command T C_COM Auxiliary machine requires torque T AUX_REQ The total command torque T obtained by summing them up SUM_COM Not exceeding the engine output torque T E The following example illustrates this decision-making method.

[0109] The engine torque distribution calculation unit 115 calculates the total target torque value T. SUM_TGT Exceeding engine output torque TE Quantity (T) SUM_TGT -T E ), so that the specified value Y is multiplied by the work correction rate η I The obtained operating drive torque correction value C I Multiply the specified value Y by the driving correction rate η C The resulting driving torque correction value C C The sum of (C) I +C C The specified value Y is determined by the method of equality.

[0110] At this time, the engine torque distribution calculation unit 115 will calculate the target torque T. I_TGT Subtract the operating drive torque correction value C I The obtained value is determined as the operating drive torque command T. I_COM The driving target torque T C_TGT Subtract the driving torque correction value C C The obtained value is determined as the driving torque command T. C_COM Therefore, the operating drive torque command T remains unchanged. I_COM With driving torque command T C_COM The ratio, in terms of the total command torque T SUM_COM Not exceeding the engine output torque T E The method determines the working drive torque command T I_COM and driving torque command T C_COM .

[0111] In addition, the total target torque value T SUM_TGT Compared to engine output torque T E Under large conditions, the operating drive torque command T I_COM and driving torque command T C_COM The method for determining this is not limited to this. For example, the engine torque distribution calculation unit 115 can also perform a calculation by subtracting only the target torque T. I_TGT and driving target torque T C_TGT The correction of one of the components determines the operating drive torque command T. I_COM and driving torque command T C_COM So that the total commanded torque value T SUM_COM Not exceeding the engine output torque T E .

[0112] The following is for reference Figure 9 The control processing of the main controller 100 is explained. Figure 9The control processing of the main controller 100 shown is initiated, for example, by turning on the ignition switch (engine key switch), and after an initial setting (not shown), it is repeatedly executed at a predetermined control cycle. Furthermore, in the initial setting, the up-run determination flag is set to off.

[0113] In step S110, the remaining driving time calculation unit 111 calculates the remaining driving time t as described above. C .

[0114] In step S120 following step S110, the remaining work time calculation unit 112 calculates the remaining work time t as described above. I .

[0115] In step S130, following step S120, the lifting operation determination unit 113 performs a lifting operation determination flag setting process. At this time, if the bucket angle θ is not above the first angle threshold θa, or if the bottom pressure of the boom cylinder 4 is less than a predetermined pressure threshold, the lifting operation determination unit 113 determines that lifting operation has not started. In this case, the lifting operation determination unit 113 keeps the lifting operation determination flag closed.

[0116] On the other hand, if the bucket angle θ is greater than or equal to the first angle threshold θa and the bottom pressure of the boom cylinder 4 is greater than or equal to a predetermined pressure threshold, the lifting operation determination unit 113 determines that lifting operation has started. In this case, the lifting operation determination unit 113 switches the lifting operation determination flag from off to on.

[0117] When the setting process of the ascending operation determination flag is completed, the control process proceeds to step S140. In step S140, the main controller 100 determines whether the mode switching switch 54 is set to automatic mode or manual mode. If it is determined that it is set to automatic mode, the control process proceeds to step S150. On the other hand, if it is determined that it is set to manual mode, the control process proceeds to step S170.

[0118] In step S150, the main controller 100 determines whether the work vehicle 1 is in the process of loading (in other words, whether the work vehicle 1 is in a state of upward movement). If the upward movement determination flag is set to "on", it is determined that the work vehicle 1 is in the process of loading (in other words, the work vehicle 1 is in a state of upward movement), and the control process proceeds to step S160. Conversely, if the upward movement determination flag is set to "off", it is determined that the work vehicle 1 is not in the process of loading (in other words, the work vehicle 1 is not in a state of upward movement), and the control process proceeds to step S170.

[0119] In step S160, the correction rate setting unit 114, as described above, determines the remaining driving time t based on the remaining driving time. C and remaining time for the assignment t I To set the driving correction rate η C and job correction rate η I .

[0120] In step S170 following step S160, the engine torque distribution calculation unit 115 calculates the torque distribution according to the correction rate η as described above. C η I Engine output torque T E Auxiliary machine requires torque T AUX_REQ The required torque T for the operation I_REQ and the required torque T for driving C_REQ Calculate the driving torque command T for the operation. I_COM and driving torque command T C_COM Thus, the series of control processes came to an end.

[0121] The operating drive torque command T calculated by the engine torque distribution calculation unit 115 I_COM The output is sent to a pump controller (not shown). The pump controller operates according to 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 (displacement) 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). Therefore, the stick 2 is driven by the working drive force generated by the stick cylinder 4, and the bucket 3 is driven by the working drive force generated by the bucket cylinder 5. Thus, the main controller 100 of this embodiment controls the discharge capacity of hydraulic pump 30A by outputting the generated control signal to a regulator (not shown) to control the discharge capacity of hydraulic pump 30A. Therefore, the stick 2 is driven by the working drive force generated by the stick cylinder 4, and the bucket 3 is driven by the working drive force generated by the bucket cylinder 5. Thus, the main controller 100 of this embodiment controls the discharge capacity of hydraulic pump 30A based on the remaining travel time t during the lifting operation. C and remaining time for the assignment t I To set the job correction rate η I According to the set operation correction rate η I To calculate and output the work drive torque command T I_COM This controls the operating torque.

[0122] In addition, the driving torque command T calculated by the engine torque distribution calculation unit 115 C_COM The output is sent to the inverter 42 for the drive motor. The inverter 42 for the drive motor outputs the drive torque command T. C_COM The drive motor 43 is used to drive the vehicle. The torque generated by the drive motor 43 is transmitted to the wheels 7 of the vehicle 11 via the power transmission device constituting the vehicle 11. Therefore, the vehicle 11 is driven by the driving force generated by the drive motor 43. Thus, the main controller 100 of this embodiment calculates the remaining travel time t during the upward operation. C and remaining time for the assignment t ITo set the driving correction rate η C According to the set driving correction rate η C To calculate and output the driving torque command T C_COM This controls the driving torque.

[0123] The following is for reference Figure 10 The effects of the work vehicle 1 in this embodiment will be explained. Figure 10 In this example, the road surface leading to the loading object is sloping upwards, and the work vehicle 1 in this embodiment performs a simple upward movement. Furthermore, to make the effect of this embodiment clearer, a comparison is made with a case without an automatic mode (i.e., without considering the correction rate η). C η I The existing examples will be described in comparison. Furthermore, in the work vehicle 1 of this embodiment and the comparative example, the operator's operation process and amount of operation for various operating parts are the same.

[0124] exist Figure 10 In the diagram, solid lines represent the operation of the main controller 100 of the work vehicle 1 in this embodiment, and dashed lines represent the operation of the main controller of the comparative example. Figure 10 The horizontal axis represents time (elapsed time). Figure 10 The vertical axis of (a) represents the remaining time difference Δt calculated by the correction rate setting unit 114. C-I , Figure 10 In (b), the vertical axis represents the driving correction rate ηC set by the correction rate setting unit 114. Figure 10 The vertical axis of (c) represents the operation correction rate η set by the correction rate setting unit 114. I , Figure 10 The vertical axis of (d) represents the driving torque command T calculated by the engine torque distribution calculation unit 115. C_COM , Figure 10 The vertical axis of (e) represents the operating drive torque command T calculated by the engine torque distribution calculation unit 115. I_COM .

[0125] In addition, Figure 10 In this embodiment, time T0 is the moment when the operator begins the simple lifting operation, the work vehicle 1 raises the boom 2, and begins to move the vehicle body 8 forward. That is, time T0 is the moment when the lifting operation determination flag is set to open. Time T1 is the moment in the comparative example when the boom 2 rises to the height required for unloading. Time T2 is the moment in the comparative example when the vehicle moves forward to the target lifting distance. Time Ta is the moment in this embodiment when the boom 2 rises to the height required for unloading and moves forward to the target lifting distance.

[0126] like Figure 10 As shown in (a), the remaining time difference Δt C-I The time difference Δt is small before time T0. This is because, before time T0, the working vehicle 1 has not yet started its ascent. Furthermore, at time T0, the working vehicle 1 raises the boom 2 and moves the vehicle body 8 forward; therefore, the remaining time difference Δt is small. C-I Variation. Here, we assume the road surface uphill up to the loaded object; therefore, the remaining travel time t... C Compared to the remaining time t of the task I Long, remaining time difference Δt C-I A sharp rise.

[0127] like Figure 10 As shown in (b) of this embodiment, during the period from when the ascent operation determination flag is set to on to when it is set to off (time T0 to time Ta), that is, during the period when the main controller 100 determines that ascent operation is to be performed, the remaining time difference Δt C-I Large, therefore, driving correction rate η C Keep it small (in other words, keep it low). Therefore, as... Figure 10 As shown in (d) in the figure, the driving torque command of this embodiment is higher than that of the comparative example during all periods.

[0128] On the other hand, such as Figure 10 As shown in (c) in this embodiment, from time T0 to the remaining time difference Δt C-I During the period when the rate is 0, the work correction rate η I Increase. Therefore, as Figure 10 As shown in (e), from time T0 to the remaining time difference Δt C-I During the period up to 0, the operating drive torque command of this embodiment is lower than that of the comparative example.

[0129] In addition, such as Figure 10 As shown in (e), in this embodiment, the operating drive torque command is lower than that in the comparative example, and correspondingly, the total target torque value T is lower. SUM_TGT Less than the comparative example. Therefore, the engine output that can be allocated to driving torque commands increases, such as... Figure 10 As shown in (d) in the figure, the driving torque command of this embodiment is higher than that of the comparative example.

[0130] As described above, when the vehicle speed is difficult to increase due to the slope angle of the road surface leading to the load, the time T2 for completing forward travel in the comparative example is longer than the time T1 for completing the boom lift in the simple lifting operation. That is, in the comparative example, although the boom is lifted at an earlier stage, time is wasted in the slow approach to the load 92 (dump truck). Therefore, in the comparative example, to make the time for completing forward travel coincide with the time for completing the boom lift, the operator needs to adjust the boom control lever based on the vehicle's travel distance, vehicle speed, boom angle, and boom angular velocity. As a result, the operator's workload increases.

[0131] In contrast, in the work vehicle 1 of this embodiment, the main controller 100 sets the travel correction rate η based on the vehicle's travel distance, speed, stick angle, and stick angular velocity. C and job correction rate η I According to the set driving correction rate η C and job correction rate η I By achieving a balance between the working drive torque command and the traveling drive torque command, the time for completing the boom lift is longer than in the comparative example, while the time for completing the forward travel is shorter. Therefore, the working vehicle 1 according to this embodiment can ensure that the time for completing the forward travel is consistent with the time for completing the boom lift, even during simple lifting operations, thus reducing the operator's workload.

[0132] Furthermore, by achieving a balance between the work drive torque command and the travel drive torque command, the time required for the work vehicle 1 to ascend is shorter (ΔT) compared to the comparative example. P =T2-Ta, refer to Figure 10 This improves the loading efficiency of the work vehicle 1. Furthermore, the time required for lifting is shortened, which correspondingly saves engine torque supplied to the engine, hydraulic pump, and generator, thus improving fuel efficiency compared to the comparative example.

[0133] As described above, in the work vehicle 1 according to this embodiment, during lifting operation, a correction rate η is set based on the travel distance, speed, boom angle, and boom angular velocity of the work vehicle 1. C η I Therefore, it is possible to make the moment when the boom is fully raised and the moment when forward travel is fully completed during the lifting operation nearly equal, regardless of the operator's skill level. As a result, it is possible to reduce the operator's workload, improve operational efficiency, and increase fuel efficiency.

[0134] In addition, the driving torque and the operating torque are both corrected by a correction rate η. C η IAdjustments are made to ensure that even when the time for stick elevation to complete is longer than the time for forward travel to complete, the completion times of stick elevation and forward travel can be made approximately equal, thus reducing the operator's workload. Furthermore, the travel drive torque and the work drive torque are both adjusted with a correction rate η. C η I Adjustments are made sequentially, thus reducing the operator's workload even when road conditions vary with different inclination angles. Furthermore, according to the work vehicle 1 of this embodiment, even when the amount of material loaded into the bucket 3, the road conditions change according to the loading cycle, or when they change in real time during the lifting operation, the balance between the driving torque and the working torque can be made close to an appropriate value, thus reducing the operator's workload.

[0135] [Second Implementation]

[0136] The following is for reference Figure 11 The work vehicle 1 of the second embodiment will be described. The work vehicle 1 of this embodiment has the same structure as the work vehicle 1 of the first embodiment, but the processing of the main controller 100 is different from that of the first embodiment.

[0137] Specifically, such as Figure 11 As shown, at time Tb after a predetermined time ΔTq has elapsed from the moment the ascent operation determination flag is set to open (T0), the remaining travel time calculation unit 111 calculates the remaining travel time t. C The remaining time calculation section 112 calculates the remaining time t of the task. I The correction rate setting unit 114 sets the correction rate based on the calculated remaining driving time t. C and remaining time for the assignment t I Set the operation correction rate η I and driving correction rate η C Maintain the set correction rate η C and η I This continues until the ascent operation determination flag changes from on to off. When the ascent operation determination flag changes from on to off, the main controller 100 will adjust the correction rate η. C η I Initialized to the base value η C0 η I0 .

[0138] The specified time ΔTq can be appropriately set based on the work content, performance, and computing power of the main controller 100 of the work vehicle 1. Furthermore, to improve calculation accuracy, a longer specified time ΔTq is better; for example, by ensuring approximately 0.1 seconds, the remaining travel time t can be calculated with a certain level of accuracy. C and remaining time for the assignment tI Furthermore, the time from the start of the ascent and descent of the work vehicle 1 to its end (time T0 to time Ta) is approximately 10 seconds. Therefore, the specified time ΔTq is preferably a value of 0.1 seconds or more and 10 seconds or less.

[0139] Furthermore, the time from when the operator operates the stick control lever 52 of the work vehicle 1 to when the stick 2 begins to move is approximately 0.5 seconds, and the time from when the hydraulic pressure used to move the stick 2 increases is approximately 1.5 seconds. Therefore, the specified time ΔTq is preferably set within the range of 0.5 seconds or more and 1.5 seconds or less.

[0140] The main controller 100 maintains the remaining driving time t calculated at time Tb. C and remaining time for the assignment t I Set correction rate η C η I This continues until the lifting operation determination flag switches from open to closed. Therefore, even if the operator releases the accelerator pedal 58 or returns the boom control lever 52 to its original position during the lifting operation, or if the speed of the work vehicle 1 temporarily decreases or the boom angular velocity decreases during the lifting operation, the correction rate η... C η I It also remains unchanged. Therefore, for example, in a single loading operation, if the operator moves the work vehicle 1 forward and backward multiple times or interrupts the upward movement, an appropriate correction rate η can be pre-set for subsequent operations. C η I .

[0141] The work vehicle 1 according to this embodiment can not only achieve the same effect as the first embodiment, but also perform loading operations in a variety of work patterns as described above, thus increasing the degree of freedom in loading operations.

[0142] [Third Implementation Method]

[0143] The following is for reference Figure 12 The work vehicle 1 of the third embodiment will be described. The work vehicle 1 of this embodiment differs from the first embodiment in the method of setting the driving correction rate and the work correction rate based on the correction rate setting unit 114A.

[0144] Specifically, such as Figure 12 As shown, when the upward operation determination flag is set to open, the correction rate setting unit 114A calculates the remaining driving time t based on the remaining driving time t calculated by the remaining driving time calculation unit 111. C and the remaining time t of the task calculated by the remaining task time calculation unit 112 I When setting the driving correction rate and the operation correction rate, the reference will be... Figure 7 The correction rate η is set based on the correction rate chart. C The ratio η of the amount of operation of the accelerator pedal 58 acc The obtained value is set as the driving correction rate η. C ′(η C ′=η C ×η acc The set driving correction rate η C The output is sent to the engine torque distribution calculation unit 115. Similarly, the correction rate setting unit 114A will adjust the reference... Figure 7 The correction rate η is set based on the correction rate chart. I The ratio η of the amount of operation of the boom control lever 52 arm The obtained value is set as the job correction rate η. I ′(η I ′=η I ×η arm The set operation correction rate η I The output is sent to the engine torque distribution calculation unit 115. Furthermore, the ratio η of the accelerator pedal 58's operation amount... acc and the ratio η of the operating amount of the boom control lever 52 arm For example, it can be set based on empirical values ​​and pre-stored in the ROM102 of the main controller 100.

[0145] Therefore, in this embodiment, the main controller (control device) 100A controls the working drive torque in such a way that the less the amount of operation of the stick operating lever 52 driving the stick 2 is, the smaller the working drive torque is, and controls the driving drive torque in such a way that the less the amount of operation of the accelerator pedal 58 driving the wheels 7 is, the smaller the driving drive torque is. Therefore, since the amount of operation of the operating unit, which is directly related to the operator's intention to operate the work vehicle 1, is proportional to the correction rate in the lifting operation control, it is possible to further reflect the operator's intention and reduce the discomfort felt by the operator.

[0146] Furthermore, various modifications are also considered in this invention.

[0147] [Variation Example 1]

[0148] For example, the operating drive torque command T based on the engine torque distribution calculation unit 115 I_COM and driving torque command T C_COM The calculation method is not limited to the method described in the above embodiments. The engine torque distribution calculation unit 115 can also calculate the driving correction rate ηC and the operation correction rate η set by the correction rate setting unit 114. I Engine output torque T E Auxiliary machine requires torque T AUX_REQ The required torque T for the operationI_REQ and the required torque T for driving C_REQ Calculate the operating drive torque command T as follows: I_COM and driving torque command T C_COM .

[0149] Specifically, the engine torque distribution calculation unit 115 first calculates the required torque T for the operation. I_REQ Required torque T for driving C_REQ And auxiliary equipment required torque T AUX_REQ The total required torque value T is obtained by summing them up. SUM_REQ (T SUM_REQ =T I_REQ +T C_REQ +T AUX_REQ ).

[0150] Next, the engine torque distribution calculation unit 115 calculates the total required torque value T. SUM_REQ Engine output torque T E In the following cases, based on the driving correction rate η C and work correction rate η I This causes the specified amount to change from the required torque T during operation. I_REQ and the required torque T for driving C_REQ Increase engine output torque T E Total torque T SUM_REQ The difference ΔT E The corresponding quantities are used to calculate the target torque T. I_TGT and driving target torque T C_TGT In this case, the engine torque distribution calculation unit 115 causes the auxiliary machine to require torque T. AUX_REQ Target torque T I_TGT and driving target torque T C_TGT The total target torque T obtained by summing them up SUM_TGT With engine output torque T E equal.

[0151] In this way, in addition to aligning the completion time of forward travel with the completion time of boom raising during the upward movement, it also shortens the time required for the upward movement, thus further improving operational efficiency.

[0152] [Variation Example 2]

[0153] Furthermore, in the above embodiment, an example of using a travel motor 43 as the prime mover to supply power to the travel device 11 was described, but there may be multiple prime movers. For example, it can be configured to use two travel motors 43 that are directly connected to the front wheel 7A in a 1-to-1 manner, or to use four travel motors 43 that are directly connected to the four wheels 7 in a 1-to-1 manner, or to integrate the front wheel 7A, the rear wheel 7B and the travel motors 43 into one unit.

[0154] [Variation Example 3]

[0155] Furthermore, in the above embodiment, an example was described whereby the drive system of the working device 6 transmits the power of the engine 20 to the hydraulic drive system of the working device 6 by converting the working oil discharged from the hydraulic pump 30A into mechanical energy using the boom cylinder 4 and bucket cylinder 5. However, the present invention is not limited to this. The drive system of the working device 6 can also be an electric drive system. For example, the boom cylinder 4 and bucket cylinder 5 may not be hydraulic cylinders, but electric cylinders driven by electricity generated by the generator motor 40.

[0156] [Variation Example 4]

[0157] Furthermore, in the above embodiment, an example was described where the inverter 41 for the generator motor and the inverter 42 for the travel motor are connected via a DC section 44, but the present invention is not limited thereto. The inverter 41 for the generator motor and the inverter 42 for the travel motor may also be power conversion devices that do not pass through a DC section, such as a matrix converter.

[0158] [Variation Example 5]

[0159] Furthermore, in the above embodiment, an example of a work vehicle 1 without an energy storage device connected to the DC unit 44 was described, but the present invention is not limited thereto. The present invention can also be applied to work vehicles that connect an energy storage device having 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.

[0160] [Variation Example 6]

[0161] Furthermore, the methods for determining whether ascent operation has begun and for calculating the remaining travel time and remaining operation time are not limited to the methods described in the above embodiments. For example, it is also possible to determine whether ascent operation has begun and calculate the remaining travel time and remaining operation time based on image data captured by an image-capturing device (operation status detection device) such as a camera monitoring the front of the work vehicle 1. Alternatively, it is also possible to determine whether ascent operation has begun and calculate the remaining travel time and remaining operation time based on information detected by an infrared sensor (travel status detection device) monitoring the front of the work vehicle 1.

[0162] [Variation Example 7]

[0163] Furthermore, in the above embodiments, to avoid interference and noise, the values ​​used for various judgments and calculations can also be processed by moving average or low-pass filtering. Additionally, by adjusting the correction rate η... C η I Applying moving average processing and low-pass filtering can suppress the correction rate η caused by sudden changes in vehicle speed or boom angular velocity after the start of ascent. C η I Due to the dramatic fluctuations, it is possible to improve operability.

[0164] [Variation Example 8]

[0165] Furthermore, while the above embodiments described an example of an electrically driven wheel loader, the present invention can also be applied to hydraulically driven wheel loaders. For example, the present invention can also be applied to wheel loaders that employ an HST (Hydraulic Static Transmission) type power transmission device as a travel device, which is configured by a closed-loop connection between a travel hydraulic pump and a travel hydraulic motor, converting the power of the engine 20 into hydraulic power and transmitting it to the wheels 7. In this case, the HST hydraulic pump functions as a secondary prime mover.

[0166] [Variation Example 9]

[0167] Furthermore, in the above embodiment, the correction rate setting unit 114 sets the correction rate η based on the remaining driving time and the remaining operation time. C η I The example provided is not limited to this invention. The correction rate setting unit 114 may also set the correction rate η based on the vehicle speed and stick angular velocity, or the travel distance and stick angle. C η I In this case, the amount of control processing by the main controller 100 can be reduced, thereby increasing the processing speed of the main controller 100.

[0168] [Variation Example 10]

[0169] In addition, the functions of the main controller 100 described in the above embodiments can also be partially or fully implemented by hardware (e.g., a device that executes the logic of each function through integrated circuit design).

[0170] [Variation Example 11]

[0171] Furthermore, in the above embodiment, the engine torque distribution calculation unit 115 calculates the required torque T based on the driving requirements. C_REQand driving correction rate η C Calculate the target torque T C_TGT According to the work requirements, torque T I_REQ and work correction rate η I Calculate the target torque T I_TGT Examples have been given, but the present invention is not limited thereto. For example, the driving correction rate η set by the correction rate setting unit 114 may not be used. C and the work correction rate η I The output is sent to the engine torque distribution calculation unit 115, and the main controller 100 calculates the driving correction rate η. C The value obtained by multiplying the amount of accelerator pedal operation by 58 is the required torque T for driving. C_REQ Calculate the job correction rate η I The value obtained by multiplying the amount of operation of the boom control lever 52 is used as the required torque T for operation. I_REQ .

[0172] 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.

[0173] Explanation of reference numerals in the attached figures

[0174] 1. Operating vehicles

[0175] 2. Bucket pole

[0176] 3 buckets

[0177] 4. Spool cylinder

[0178] 5. Bucket cylinder

[0179] 6. Operating device

[0180] 7 wheels

[0181] 8. Body

[0182] 11. Driving device

[0183] 15 Steering cylinder

[0184] 17 Brake cylinder

[0185] 18 Parking brake cylinder

[0186] 20 Engines

[0187] 30A Hydraulic Pump (Working Prime Motion)

[0188] 30B and 30C hydraulic pumps

[0189] 40 Generator motor (prime motor for driving)

[0190] 41 Inverters for generator motors

[0191] 42 Inverter for traveling motor

[0192] 43. Travel motor (prime motor)

[0193] 51 Forward / Reverse Switch

[0194] 52. Bucket control lever

[0195] 53 Bucket Operating Lever

[0196] 54 Mode switching switch (mode switching device)

[0197] 58 Accelerator Pedal

[0198] 61 Vehicle speed sensor (driving status detection device)

[0199] 62. Boom relative angle sensor (operational status detection device)

[0200] 63 Bucket relative angle sensor (operational status detection device)

[0201] 100, 100A Main Controller (Control Device)

[0202] 111 Remaining Driving Time Calculation Department

[0203] 112 Remaining Time Calculation Department

[0204] 113 Ascending Operation Judgment Department

[0205] 114, 114A Correction Rate Setting Section

[0206] 115 Engine Torque Distribution Calculation Unit.

Claims

1. A working vehicle, comprising: A driving mechanism that enables the vehicle body to move; A prime mover that supplies driving force to the driving device; The working device is mounted on the vehicle body and has a stick that can rotate in the vertical direction and a bucket that is connected to the front end of the stick and mounted in a manner that can rotate in the vertical direction. A boom control lever, used for operating the boom; Accelerator pedal, used to accelerate the vehicle body; The prime mover supplies the working device with the driving force for operation; A driving status detection device that detects the driving status of the vehicle body, including vehicle speed and driving distance; An operation status detection device that detects the operation status of the operation device, including the angle of the boom; The control device controls the driving prime mover and the working prime mover. Its features are, The control device determines, based on the driving state of the vehicle body detected by the driving state detection device and the operating state of the operating device detected by the operating state detection device, whether the specific conditions for raising the boom during loading operations are met. When the control device determines that the specific conditions are met, it sets a driving correction rate for adjusting the driving force and a working correction rate for adjusting the working driving force based on the vehicle speed and driving distance detected by the driving state detection device, the stick angle detected by the working state detection device, a preset target driving distance, and a preset target stick angle. The control device controls the driving force of the driving prime mover and the working prime mover according to the set driving correction rate and working correction rate, so that the moment when the stick angle reaches the target stick angle coincides with the moment when the vehicle body reaches the target travel distance. The control device calculates the remaining time to reach the target distance based on the vehicle speed, the distance traveled, and the target distance. The control device calculates the remaining time to reach the target stick angle based on the stick angle and the target stick angle, as the remaining operation time. The control device sets the driving correction rate and the operation correction rate based on the calculated remaining driving time and remaining operation time. The control device controls the torque of the driving prime mover and the working prime mover according to the set driving correction rate and the working correction rate. The specific condition is based on the condition that the upward movement of the work vehicle begins when the angle of the bucket is above a predetermined angle threshold and the amount of operation of the accelerator pedal and the stick control lever increases. The remaining driving time is calculated using the following formula: Among them, t C d represents the remaining driving time. RR Let d1 represent the distance traveled during the ascent, d1 represent the distance traveled at time t1 after a predetermined time elapsed from the start time t0 of the ascent, and v1 represent the speed of the working vehicle at time t1. The remaining time for the task is calculated using the following formula: Among them, t I θ represents the remaining time for the task. RR The target stick angle is θ1, which represents the stick angle at time t1 after a predetermined time elapsed from the start of the ascent operation t0. θ1 This represents the boom angular velocity of the working vehicle at time t1.

2. The working vehicle according to claim 1, characterized in that, The shorter the remaining operating time compared to the remaining travel time, the higher the operating correction rate set by the control device, in order to limit the upward speed of the boom. The longer the remaining operation time compared to the remaining driving time, the greater the driving correction rate the control device sets, in order to limit the vehicle speed.

3. The operating vehicle according to claim 1 or 2, characterized in that, The prime mover is a motor.

4. The operating vehicle according to claim 1 or 2, characterized in that, The work vehicle also has a mode switching device that switches between an execution mode and a prohibition mode. The execution mode executes the settings of the driving correction rate and the work correction rate, while the prohibition mode prohibits the execution of the settings of the driving correction rate and the work correction rate.

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