WORK MACHINE AND WORK MACHINE TAX PROCEDURES

Abstract

Suppressing a vehicle body vibration. A working machine includes a vehicle body, a working device attached to the vehicle body to enable its operation and which includes an attachment at its head end, a control device configured to issue an operating command to cause the attachment to operate, a vibration sensor configured to detect a vibration of the vehicle body, and a control unit configured to set an operating limit for the attachment in response to the operating command, based on the result of detecting the vibration of the vehicle body generated by the operation of the attachment.

Description

TECHNICAL AREA

[0001] The disclosure relates to a working machine and a control procedure for a working machine. STATE OF THE ART

[0002] A known method is described in JP 2021-43804 A (Patent Reference 1). In this machine, a transmission unit that transmits force to an operating lever for operating a work device is controlled based on the acceleration of a vehicle's main body, and the magnitude of the force transmitted to the operating lever is automatically adjusted. LIST OF COUNTERPOINTS Patent Literature

[0003] Patent Literature 1: JP 2021-43804 A BRIEF DESCRIPTION OF THE INVENTION Technical Problem

[0004] If a control lever is shaken by a vibration of the vehicle body of a work machine, an input from the control lever is unintentionally applied to a work device, and the vibration of the vehicle body can be further amplified by the shaking of the work device.

[0005] The revelation proposes a working machine and a control method for a working machine with which a vibration of a vehicle body can be suppressed. Solution to the problem

[0006] A working machine according to the disclosure includes a vehicle body, a working device attached to the vehicle body in such a way that it can work and which includes an attachment at the head end of the working device, an operating device configured to issue an operating command to cause the attachment to work, a vibration sensor configured to detect a vibration of the vehicle body, and a control unit configured to set an operating limit for the attachment in response to the operating command based on a result of detecting the vibration of the vehicle body generated by the work of the attachment.

[0007] A control method for a working machine according to the disclosure includes receiving the input of an operator command to cause an attachment on a head end of a working device that is attached to a vehicle body in such a way that it can work, detecting a vibration of the vehicle body generated by the work of the attachment, and setting an operating limit for the attachment in response to the operator command based on a result of detecting the vibration of the vehicle body. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0008] According to a working machine and a control method for a working machine as disclosed, a vibration of a vehicle body can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a side view of a wheel loader as an example of a work machine. Fig. Figure 2 is a schematic block diagram illustrating a configuration of an entire system including the wheel loader. Fig. Figure 3 is a schematic view of an operating lever. Fig. Figure 4 is a block diagram illustrating a functional configuration of a work tool control unit. Fig. Figure 5 is a flowchart illustrating an example of a control system for bucket operation. Fig. Figure 6 is a first graph showing the flow rate of hydraulic oil supplied to a paddle cylinder. Fig. Figure 7 is a second graph showing the flow rate of the hydraulic oil supplied to the paddle cylinder. DESCRIPTION OF EXECUTION FORMS

[0009] With reference to the drawings, embodiments are described below. In the following description, identical components and elements are designated by the same reference numerals. The names and functions of these components are also identical. Accordingly, a detailed description of these is not repeated. Configurations may be omitted or simplified in the drawings to simplify the description. It is intended that any configurations can be taken from the embodiments and combined in a variety of ways. Overall configuration of the wheel loader 1

[0010] In one embodiment, a wheel loader 1 is described as an example of a working machine. Fig. Figure 1 is a side view of the wheel loader 1 as an example of the working machine based on the embodiment.

[0011] As in Fig. As illustrated in Figure 1, the wheel loader 1 includes a vehicle body frame 2, a working attachment 3, a drive system 7, and a cab 5. The vehicle body (main working machine body) of the wheel loader 1 is configured with the vehicle body frame 2, the cab 5, and the like. The working attachment 3 and the drive system 7 are attached to the vehicle body of the wheel loader 1.

[0012] The drive mechanism 7 causes the vehicle body of the wheel loader 1 to move and includes the driving wheels 7A and 7B. The wheel loader 1 is a wheeled vehicle that incorporates the driving wheels 7A and 7B as rotating moving bodies on both sides of the vehicle body, oriented left-right. The wheel loader 1 is self-propelled by the rotating driving wheels 7A and 7B and is capable of performing the desired tasks using the attachment 3.

[0013] In this description, the direction in which the wheel loader 1 travels linearly is referred to as the forward-reverse direction of the wheel loader 1. In the forward-reverse direction of the wheel loader 1, one side relative to the vehicle body frame 2, on which the working attachment 3 is mounted, is referred to as the forward direction, and one side opposite the forward direction is referred to as the reverse direction. The left-right direction of the wheel loader 1 is a direction orthogonal to the forward-reverse direction in the plan view of the wheel loader 1 on level ground. The right and left sides in the left-right direction, as they face the forward direction, are the right and left directions, respectively. The up-down direction of the wheel loader 1 is a direction orthogonal to a plane defined by the forward-reverse direction and the left-right direction.In the up-down direction, a side near the ground is the underside and a side near the sky is the top.

[0014] The vehicle body frame 2 includes a front frame 2A and a rear frame 2B. The front frame 2A is positioned in front of the rear frame 2B. The front frame 2A is connected to the rear frame 2B in such a way that it is flexible. The front frame 2A and the rear frame 2B form the vehicle body frame 2 with an articulated structure. The wheel loader 1 is an articulated work machine in which the front frame 2A and the rear frame 2B are connected to each other.

[0015] The working unit 3 and a pair of the left and right wheels for driving (front wheels) 7A are attached to the front frame 2A. The working unit 3 is positioned in front of the vehicle body and is supported by the vehicle body of the wheel loader 1. The working unit 3 includes a boom 32 and a bucket 31. The bucket 31 is located at one end of the working unit 3. The bucket 31 is a working tool for digging and loading. The bucket 31 is an example of an attachment that is detachably mounted at one end of the boom 32. Depending on the type of work, the attachment is replaced by a grapple, a fork, a plow, or the like.

[0016] The working device 3 includes a boom cylinder 36. The front frame 2A and the boom 32 are connected by a pair of boom cylinders 36. One base end of the boom cylinder 36 is attached to the front frame 2A. One head end of the boom cylinder 36 is attached to the boom 32. The boom cylinder 36 is a hydraulic actuator that causes the boom 32 to move up and down relative to the front frame 2A. Along with the raising and lowering of the boom 32, the bucket 31 attached to the head end of the boom 32 is also raised and lowered. The working device 3 is attached to the front frame 2A in such a way that it can operate.

[0017] The working device 3 further includes a deflection lever 33, a connecting link 34, and a bucket cylinder 35. The deflection lever 33 is rotatably mounted on the boom 32, essentially at its midpoint. The bucket cylinder 35 connects the deflection lever 33 to the front frame 2A. The connecting link 34 is connected to a head end section of the deflection lever 33. The connecting link 34 connects the deflection lever 33 to the bucket 31.

[0018] A base end of the bucket cylinder 35 is attached to the front frame 2A. A head end of the bucket cylinder 35 is attached to a base end section of the deflection lever 33. The bucket cylinder 35 is a hydraulic actuator that rotates the bucket 31 up and down relative to the boom 32. The bucket cylinder 35 is a working tool cylinder that drives the bucket 31. The bucket 31 is configured to operate relative to the boom 32.

[0019] The cabin 5, into which an operator enters, and a pair of left and right wheels for driving (rear wheels) 7B are attached to the rear frame 2B. The box-shaped cabin 5 is located behind the boom 32. The cabin 5 is positioned above the vehicle body frame 2. Inside the cabin 5 are a seat for an operator, an operating device as described below, and the like. The cabin 5 can also be mounted on the front frame 2A. System configuration

[0020] Fig. Figure 2 is a schematic block diagram illustrating a configuration of a complete system, including the wheel loader 1, according to the embodiment. The wheel loader 1 includes an implement control unit 10, a motor 11, and a power take-off (PTO) shaft 12.

[0021] The engine 11 is a power source that generates motive power to drive the implement 3 and is, for example, a diesel engine. The output power of the engine 11 is controlled by adjusting the amount of fuel injected into a cylinder of the engine 11. The power take-off (PTO) 12 distributes the output power of the engine 11 to a drive system, which drives the drive mechanism 7, and a hydraulic system, which drives the implement 3. The engine 11, the PTO 12, and the hydraulic system are mounted behind the cab 5 of the rear frame 2B.

[0022] The hydraulic device system is a mechanism primarily for driving the working implement 3 (for example, the boom 32 and the bucket 31). The hydraulic device system includes a hydraulic pump 21 for the working implement driven by the power take-off shaft 12, a hydraulic pilot valve 22 for bucket actuation and a hydraulic pilot valve 23 for boom actuation, which are arranged in an outlet circuit of the hydraulic pump 21, electromagnetic proportional control valves 24, 25 for the bucket, which are connected to the respective pilot pressure receiving sections of the bucket actuation valve 22, and electromagnetic proportional control valves 26, 27 for the boom, which are connected to the respective pilot pressure receiving sections of the boom actuation valve 23.

[0023] The working device 3 is driven by hydraulic oil from the hydraulic pump 21. The hydraulic pump 21 is driven by the motor 11 and delivers the hydraulic oil to operate the working device 3. The boom 32 is raised and lowered by the boom cylinder 36, which is supplied with hydraulic oil from the hydraulic pump 21 and extends and retracts. The bucket 31 rotates up and down by the bucket cylinder 35, which is supplied with hydraulic oil from the hydraulic pump 21 and extends and retracts.

[0024] The electromagnetic proportional control valves 24 to 27 are connected to a pilot pump (not illustrated) and control the supply of pilot oil from the pilot pump to the respective pilot pressure receiving sections of the boom actuation valve 23 and the bucket actuation valve 22 according to a control signal from the work equipment control unit 10.

[0025] In particular, the electromagnetic proportional control valve 24 switches the blade actuation valve 22 so that the blade cylinder 35 retracts and the blade 31 moves in a tipping direction (direction in which a cutting edge of the blade 31 lowers). Furthermore, the electromagnetic proportional control valve 25 switches the blade actuation valve 22 so that the blade cylinder 35 extends and the blade 31 moves in a pivoting direction (direction in which the cutting edge of the blade 31 raises).

[0026] The electromagnetic proportional control valve 26 switches the boom actuation valve 23 so that the boom cylinder 36 retracts and the boom 32 is lowered. Furthermore, the electromagnetic proportional control valve 27 switches the boom actuation valve 23 so that the boom cylinder 36 extends and the boom 32 is raised.

[0027] The implement control unit 10 is connected to the operating device, a boom angle sensor 44, a bucket angle sensor 45, a boom ground pressure sensor 46, and an inertial measurement unit (IMU) 47. The operating device is located in the cab 5. The operating device includes a boom control lever 41 and a bucket control lever 42. The operating device also includes a steering wheel, a steering lever, an accelerator pedal, and the like (not illustrated).

[0028] The boom control lever 41 is located, for example, to the right of the seat in the cab 5. The boom control lever 41 includes a built-in lever angle sensor that detects a lever angle. The operator can manually actuate the boom control lever 41 to engage the boom 32. When the operator actsuates the boom control lever 41, the lever angle sensor detects a lever angle corresponding to a certain amount of actuation. The lever angle sensor generates a boom lever signal. The boom lever signal is an operating command that causes the boom 32 to operate according to the lever angle. The lever angle sensor outputs the boom lever signal to the implement control unit 10.

[0029] The bucket control lever 42 is located, for example, to the right of the seat in the cab 5. The bucket control lever 42 includes a built-in lever angle sensor that detects a lever angle. The operator can manually actuate the bucket control lever 42 to engage the bucket 31. When the operator actsuates the bucket control lever 42, the lever angle sensor detects a lever angle corresponding to a certain amount of actuation. The lever angle sensor generates a bucket lever signal. The bucket lever signal is an operating command that causes the bucket 31 to operate according to the lever angle. The lever angle sensor outputs the bucket lever signal to the implement control unit 10.

[0030] The boom angle sensor 44 is configured, for example, with a rotary encoder that is provided on a mounting section (a support shaft) of the boom 32 on the vehicle body frame 2. The boom angle sensor 44 detects a boom angle between a centerline of the boom 32 and a horizontal line and outputs a detection signal of the boom angle to the work tool control unit 10.

[0031] Here, the center line of the boom 32 is a line YY in Fig. 2 and is a line connecting the mounting section (a center of the support shaft) of the boom 32 to the vehicle body frame 2 and a mounting section (center of a bucket support shaft) of the bucket 31. If the line YY in Fig. When the 2 runs along the horizontal, the boom angle sensor 44 outputs a boom angle of 0 degrees. The boom angle sensor 44 outputs a positive value when the head end of the boom 32 is raised from the boom angle state of 0 degrees, and a negative value when the head end of the boom 32 is lowered.

[0032] The bucket angle sensor 45 is configured, for example, with a rotary encoder mounted on a rotary shaft of the angle lever 33, and the like. The bucket angle sensor 45 detects a bucket angle and outputs a detection signal of the bucket angle to the implement control unit 10. When the bucket 31 is on the ground, the bucket angle sensor 45 outputs a bucket angle of 0 degrees if the cutting edge of the bucket 31 is in a position where it rests horizontally on the ground. The bucket angle sensor 45 outputs a positive value when the bucket 31 is moved in the pivoting direction (upwards) and a negative value when the bucket 31 is moved in the dumping direction (downwards).

[0033] The boom ground pressure sensor 46 detects pressure on the underside of the boom cylinder 36 (boom ground pressure) and outputs a boom ground pressure detection signal to the implement control unit 10. The boom ground pressure increases when the bucket 31 is loaded and decreases when the bucket 31 is unloaded.

[0034] The IMU 47 is mounted on the chassis of the wheel loader 1. The IMU 47 is attached, for example, to the chassis frame 2 and detects the position of the chassis frame 2. The IMU 47 detects the acceleration and angular velocity of the chassis frame 2 in the forward-backward, left-right, and up-down directions. The IMU 47 is an example of an acceleration sensor that detects the acceleration of the chassis. Since the acceleration of the chassis is an example of a physical quantity that represents a vibration of the chassis, the IMU 47 can be said to be an example of a vibration sensor that detects the vibration of the chassis. The IMU 47 outputs a detection signal of the acceleration of the chassis to the implement control unit 10.

[0035] Fig. Figure 3 is a schematic view of an operating lever 43. The operating device includes the operating lever 43, which can be manually operated by the operator. The operating lever 43 is a multi-function lever that performs functions of both the boom operating lever 41 and the bucket operating lever 42. An operation of tilting the operating lever 43 in the forward-backward direction is defined as an operation to raise and lower the boom 32, and an operation of tilting the operating lever 43 in the left-right direction is defined as an operation to rotate the bucket 31. The boom angle and the bucket angle described above are set according to a tilt angle of the operating lever 43 from the neutral position.

[0036] The control lever 43 includes a base section 52, a shaft section 53, and a section 54 with an enlarged diameter. The base section 52 is attached, for example, to a right-hand console located to the right of the seat in the cabin 5. The shaft section 53 and the section 54 with an enlarged diameter can be moved as a unit so that they can be tilted forward-backward and left-right relative to the base section 52. The section 54 with an enlarged diameter forms a head end of the control lever 43. The control lever 43 encloses the section 54 with an enlarged diameter at its head end. The shaft section 53 has a rod shape. The section 54 with an enlarged diameter is shaped such that its diameter is larger than that of the shaft section 53.In cross-section perpendicular to the longitudinal direction of shaft section 53, section 54 with its increased diameter has a cross-sectional area that is larger than that of shaft section 53. The weight of the head end of the operating lever 43 is relatively high. The center of gravity of the operating lever 43 is located closer to the head end in the longitudinal direction than to the center.

[0037] The enlarged diameter section 54 includes at least one switch 55. The switch 55 can be operated by the operator. For example, the operator, seated, can operate the switch 55 with their right thumb while holding the shaft section 53 with their right palm. The operating lever 43 is a joystick that integrates the lever and the switch 55.

[0038] Switch 55 includes push-button switches 56, 57, and a toggle switch 58. Switch 55 may also include another type of switch, for example, a slide switch. Switch 55 may include an operating switch for a direction indicator. Switch 55 may include a switch for toggling between forward and reverse movement, an operating switch for the working device 3, a traction control release switch, and the like, and may include a switch with another function. Switch 55 may be provided on a rear surface of section 54 with an enlarged diameter.

[0039] The operating lever 43 encloses an electrical wire 59. The electrical wire 59 runs from the inside to the outside of the operating lever 43. The electrical wire 59 is arranged so that it passes through the shaft section 53 and the base section 52. One end of the electrical wire 59 is electrically connected to the switch 55. The electrical wire 59 transmits an electrical signal generated by actuating the switch 55. The electrical wire 59 encloses a section located inside the right console. Configuration of the work equipment control unit 10

[0040] Fig. Figure 4 is a block diagram illustrating a functional configuration of the work tool control unit 10. As shown in Fig. As illustrated in Figure 4, the work equipment control unit 10 mainly includes a vibration detection unit 101, a command calculation unit 102, a storage unit 108 and a timer 109.

[0041] The vibration detection unit 101 receives an input from the accelerometer (IMU 47) indicating the acceleration of the vehicle body. Based on this acceleration, the vibration detection unit 101 calculates the vibration of the vehicle body. The vibration detection unit 101 calculates the vibration of the vehicle body generated by the action of the bucket 31. An example of the action of the bucket 31 is a shaking motion. This shaking motion involves repeatedly moving the bucket 31 in the tipping and pivoting directions to rapidly vibrate it. The shaking motion serves to eject adhering materials such as mud from the bucket 31.The vibration detection unit 101 detects that the shaking motion of the bucket generates a strong vibration in the vehicle body, greater than or equal to a threshold value. The vibration detection unit 101 outputs a vibration detection result of the vehicle body to the command calculation unit 102.

[0042] The command control unit 102 receives an input of an operating command to actuate the bucket 31 from the operating lever 43 (bucket operating lever 42). The command control unit 102 essentially outputs a control signal (EPC current) according to the operating command to the electromagnetic proportional control valves 24 and 25 for the bucket connected to the bucket actuation valve 22.

[0043] The command control unit 102 checks the vibration of the vehicle body detected by the vibration sensing unit 101. If a strong vibration of the vehicle body is detected, the command control unit 102 outputs a control signal, obtained by correcting the input control command, to the electromagnetic proportional control valves 24 and 25. Based on the intensity of the vehicle body vibration, the command control unit 102 determines a command flow rate of the hydraulic oil supplied to the bucket cylinder 35 and outputs an EPC current to the electromagnetic proportional control valves 24 and 25 according to this command flow rate. The command control unit 102 controls the operation of the bucket cylinder 35 in response to an actuation command for the bucket control lever 42, based on the detected vibration of the vehicle body.The command calculation unit 102 changes a limit value for the movement of the bucket 31 according to the intensity of the vehicle body vibration. The command calculation unit 102 limits the operation of the bucket 31 in response to the operating command at the point in time when the vibration of the vehicle body reaches or exceeds a certain threshold.

[0044] The command control unit 102 sets a limit for the amplitude of the bucket's vibration movement to quickly set the bucket 31 into vibration. For example, the command control unit 102 limits the maximum flow rate of the hydraulic oil supplied to the bucket cylinder 35. Alternatively, the command control unit 102 reduces the permissible number of bucket vibration movements per unit of time. The command control unit 102 modifies the maximum frequency at which the operator can actuate the bucket control lever 42 to cause the bucket to vibrate, according to the intensity of the vehicle body vibration.

[0045] Storage unit 108 is a non-volatile memory and serves as a storage area for necessary data. Storage unit 108 stores a program for controlling various types of operation of the wheel loader 1, as well as various types of data required for the program's execution. Storage unit 108 also temporarily stores work data generated in connection with the operation of the wheel loader 1. The implement control unit 10 performs various processes for controlling the operation of the wheel loader 1 based on the program stored in storage unit 108. The timer 109 measures time. Control of the bucket operation

[0046] Fig. Figure 5 is a flowchart illustrating an example of a control system for the blade operation in the embodiment shown. As in Fig. Figure 5 illustrates that in step S1, the implement control unit 10 detects the acceleration of the vehicle body. The vibration detection unit 101 receives an input from the IMU 47 of a detection signal for the acceleration of the vehicle body.

[0047] When the vehicle body vibrates, it undergoes a repeated upward and downward displacement. Differentiating this displacement over time yields the velocity, and differentiating the velocity over time yields the acceleration. During vibration, the vehicle body is subjected to alternating upward and downward acceleration, with a moment when the acceleration becomes zero. The vibration detection unit 101 generates time-series data in which the acceleration of the vehicle body, as measured by the IMU 47, is arranged chronologically. From this time-series acceleration data, the vibration detection unit 101 determines a peak value for the vehicle body acceleration.

[0048] In step S2, the work tool control unit 10 determines whether the acceleration of the vehicle body is greater than or equal to a predefined threshold value. The instruction processing unit 102 reads the threshold value of the vehicle body acceleration from the storage unit 108. This threshold value is defined, for example, as the value at which no autonomous vibration of the vehicle body is generated, and is pre-stored in the storage unit 108. The instruction processing unit 102 compares the peak value of the vehicle body acceleration determined in step S1 with the threshold value read from the storage unit 108.

[0049] If the peak acceleration of the vehicle body is greater than or equal to the threshold (YES in step S2), the implement control unit 10 determines in step S3 whether a time t1 has elapsed to determine the vibration state of the bucket. The command processing unit 102 reads the time from the timer 109. The command processing unit 102 begins timing, starting from the point in time at which it is determined in step S2 that the peak acceleration of the vehicle body is greater than or equal to the threshold, and at which the control system transitions to step S3. The command processing unit 102 calculates the time elapsed up to the current time. The command processing unit 102 reads the time t1 from the storage unit 108. The command processing unit 102 compares the time elapsed up to the current time with the time t1.The command calculation unit 102 determines whether a state in which the peak value of the vehicle body acceleration is greater than or equal to the threshold value lasts for the time t1 or not.

[0050] If the condition in which the peak acceleration of the vehicle body is greater than or equal to the threshold has not yet persisted for time t1 at the time of determination in step S3 (NO in step S3), the processing of steps S1 to S3 is repeated. If, during the determination in step S2, it is determined that the peak acceleration of the vehicle body is greater than or equal to the threshold, the control proceeds to step S3 and the determination of whether the condition in which the peak acceleration of the vehicle body is greater than or equal to the threshold persists for time t1 is repeated.

[0051] If, in step S3, it is determined that the condition in which the peak value of the vehicle body acceleration is greater than or equal to the threshold value persists for time t1 (YES in step S3), in step S4 the implement control unit 10 corrects an input value from the operating device. The command calculation unit 102 corrects an input value of a bucket lever signal from the bucket control lever 42.

[0052] Fig. Figure 6 is a first graph showing the flow rate of the hydraulic oil supplied to the paddle cylinder 35. The horizontal axis in Fig. 6 represents time, and the vertical axis in Fig. Figure 6 represents the flow rate of the hydraulic oil supplied to the paddle cylinder 35. Fig. 6 indicates “0%” a state in which the bucket control lever 42 is in the neutral position, the bucket 31 is stationary and the supply of hydraulic oil to the bucket cylinder 35 is stopped.

[0053] A positive direction of the vertical axis in Fig. 6 indicates the flow rate of the hydraulic oil that is supplied to an oil chamber located on the lower side of the bucket cylinder 35 and moves the bucket 31 in the pivoting direction. Fig. 6 is “+100%” a maximum value of the flow rate of the hydraulic oil supplied to the bucket cylinder 35 to move the bucket 31 in the pivoting direction. A negative direction of the vertical axis in Fig. 6 indicates the flow rate of the hydraulic oil that is supplied to a head-side oil chamber of the bucket cylinder 35 and moves the bucket 31 in the tipping direction. Fig. 6 is “-100 %” a maximum value of the flow rate of the hydraulic oil supplied to the bucket cylinder 35 to move the bucket 31 in the tipping direction.

[0054] A dashed line in Fig. 6 indicates a target flow rate of the hydraulic oil, which is determined according to an operating command issued by the bucket control lever 42. A solid line in Fig. 6 specifies a command flow rate of the hydraulic oil after limiting the hydraulic oil flow rate. A [missing information] on the [missing information] Fig. The control signal shown in Figure 6, based on the command flow rate, is output by the command calculation unit 102 to the electromagnetic proportional control valves 24 and 25.

[0055] The bucket control lever 42, in its neutral position, begins to tilt in a direction that moves the bucket 31 in the pivoting direction at time T1. At time T2, the tilt of the bucket control lever 42 is at its maximum. After time T2 has elapsed, the tilt of the bucket control lever 42 decreases. When the bucket control lever 42 is returned to its neutral position at time T3, it immediately begins to tilt in a direction that moves the bucket 31 in the dumping direction. At time T4, the tilt of the bucket control lever 42 is at its maximum. After time T4 has elapsed, the tilt of the bucket control lever 42 decreases.

[0056] When the operator performs the shaking motion of the bucket by actuating the bucket control lever 42, the operator normally repeats actuating the bucket control lever 42 by a maximum amount to move the bucket 31 in the pivoting direction, as well as actuating the bucket control lever 42 by a maximum amount to move the bucket 31 in the dumping direction. Fig. At time T1, the operator begins actuating the bucket control lever 42 in the neutral position in the slewing direction. When the maximum actuation amount in the slewing direction is reached at time T2, the operator immediately reduces the actuation amount in the slewing direction. When the actuation amount in the dumping direction becomes zero at time T3 and the bucket control lever 42 is in the neutral position, the operator immediately begins actuating it in the dumping direction. When the maximum actuation amount in the dumping direction is reached at time T4, the operator immediately reduces the actuation amount in the dumping direction.

[0057] In the Fig. In the example shown, the maximum permissible flow rates of the hydraulic oil supplied to the bucket cylinder 35 are limited. At time T11, a target flow rate of the hydraulic oil, specified by an operating command from the bucket control lever 42, increases to a maximum permissible flow rate in the tipping direction. After time T11, the target flow rate becomes higher than the maximum permissible flow rate, but even in this case, the command flow rate is limited to the maximum permissible flow rate. Since the target flow rate drops to the maximum permissible flow rate at time T12, the command flow rate is adjusted to the target flow rate after time T12. At time T13, the target flow rate rises to a maximum permissible flow rate in the tipping direction.The target flow rate is higher than the maximum permissible flow rate in a period from time T13 to time T14, but even in this case the command flow rate is limited to the maximum permissible flow rate.

[0058] By controlling the command flow rate in this way, the amplitude A of the in Fig. The command flow rate shown in Figure 6 is made smaller than the amplitude of the target flow rate calculated according to the operating command from the bucket control lever 42. The input value of the bucket lever signal from the bucket control lever 42 is corrected, and the amount of movement of the bucket 31 is reduced. The amplitude of the movement of the bucket 31 in the tipping direction and in the pivoting direction is reduced. The control signal output to the electromagnetic proportional control valves 24 and 25 is corrected with respect to the operating command issued by the bucket control lever 42, and a limit is set for the actuation of the bucket 31. A limit is set for the amplitude of the bucket's vibrating motion.

[0059] Fig. Figure 7 is a second graph showing the flow rate of the hydraulic oil supplied to the paddle cylinder 35. Similar to in Fig. 6 represents the horizontal axis in Fig. 7 represents time, and the vertical axis in Fig. 7 represents the flow rate of the hydraulic oil supplied to the paddle cylinder 35. Fig. 7 indicates a state of "0%" in which the supply of hydraulic oil to the bucket cylinder 35 is stopped. A positive direction of the vertical axis in Fig. 7 indicates the flow rate of the hydraulic oil for moving the bucket 31 in the pivoting direction. A negative direction of the vertical axis in Fig. 7 indicates the flow rate of the hydraulic oil for moving the bucket 31 in the tipping direction.

[0060] A dashed line in Fig. 7 indicates a target flow rate of the hydraulic oil, which is determined according to an operating command issued by the bucket control lever 42. A solid line in Fig. 7 specifies a command flow rate of the hydraulic oil after limiting a rate of change of the hydraulic oil flow rate. A [missing information] on the [missing information] Fig. The control signal shown in Figure 7, based on the command flow rate, is output by the command calculation unit 102 to the electromagnetic proportional control valves 24 and 25.

[0061] In the Fig. In the example shown in Figure 7, the rate of change of the flow rate of the hydraulic oil supplied to the paddle cylinder 35 is limited, and the slope of the graph of the command flow rate, which is shown in Fig. The area indicated by the solid line 7 is limited. The area shown in Fig. 7. The command flow rate of the hydraulic oil, indicated by the solid line, is controlled to approximate the target flow rate indicated by the dashed line.

[0062] The bucket control lever 42, in its neutral position, begins to tilt in the direction in which the bucket 31 will move in the swing direction at time T1. At time T1, the command flow rate of the hydraulic oil also begins to increase in the swing direction; however, the command flow rate is lower than the target flow rate. Even as the tilt of the bucket control lever 42 decreases at time T2, the command flow rate continues to increase because it remains lower than the target flow rate. The command flow rate continues to increase until the target flow rate and the command flow rate are equal at time T5. After time T5, the target flow rate becomes lower than the command flow rate, and thus the command flow rate decreases to approach the target flow rate.

[0063] At time T3, the bucket control lever 42 is moved to the neutral position. The command flow rate continues to decrease even after time T3. When the command flow rate in the dumping direction becomes zero at time T6, the bucket control lever 42 is tilted in the direction in which the bucket 31 is moved in the dumping direction, and the command flow rate in the dumping direction is calculated, so that the command flow rate of the hydraulic oil also begins to increase in the dumping direction. Even when the tilt of the bucket control lever 42 begins to decrease at time T4, the command flow rate continues to increase because the command flow rate is still lower than the target flow rate. The command flow rate continues to increase until the target flow rate and the command flow rate are equal at time T7.After time T7, the target flow rate becomes smaller than the command flow rate, and so the command flow rate decreases to approach the target flow rate.

[0064] By controlling the command flow rate in this way, the amplitude A of the in Fig. The command flow rate shown in Figure 7 is less than the amplitude of the target flow rate calculated according to the operating command from the bucket control lever 42. The input value of the bucket lever signal from the bucket control lever 42 is corrected, and the amount of movement of the bucket 31 is reduced. The amplitude of the movement of the bucket 31 in the dumping direction and in the pivoting direction is reduced. A limit for the movement of the bucket 31 is set in response to an operating command issued by the bucket control lever 42. A limit is set for the amplitude of the vibrating movement of the bucket.

[0065] Referring again to Fig. In step S5, the implement control unit 10 determines whether the implement lever filter duration t2 has elapsed. The command calculation unit 102 reads the time from the timer 109. The command calculation unit 102 begins timing, starting from the point in time when the input value is corrected by the operating device in step S4. The command calculation unit 102 calculates the time elapsed up to the current time. The command calculation unit 102 reads the time t2 from the storage unit 108. The command calculation unit 102 compares the time elapsed up to the current time with the time t2. The command calculation unit 102 determines whether the time t2 has elapsed since the input value was corrected by the operating device.

[0066] If time t2 has not elapsed (NO in step S5), the determination in step S5 is repeated. The processing waits until time t2 has expired.

[0067] If time t2 has elapsed (YES in step S5), the work tool control unit 10 determines the acceleration of the vehicle body in step S6. In step S7, the work tool control unit 10 determines whether a peak value of the vehicle body acceleration is greater than or equal to a predefined threshold value. The processing of steps S6 and S7 is similar to the processing of steps S1 and S2.

[0068] If, during the determination in step S7, the peak value of the vehicle body acceleration is greater than or equal to the threshold value (YES in step S7), the control returns to step S4 and the processing of steps S4 to S7 is repeated. In step S4, the input value is further corrected by the operating device, and in a state where the Fig. 6 and Fig. As the amplitude A shown in Figure 7 is further reduced, step S7 determines whether the peak acceleration of the vehicle body is still greater than or equal to the specified threshold. The correction of the input value continues until the peak acceleration of the vehicle body becomes less than the threshold.

[0069] If the peak acceleration of the vehicle body falls below the threshold (NO in step S7), the implement control unit 10 changes the input correction from the control device to an initial state in step S8. The command processing unit 102 releases the limit for the operation of the bucket 31 in response to the operating command issued by the bucket control lever 42. As a result of the operating command, no limit for the operation of the bucket 31 is defined. The command processing unit 102 outputs a control signal to the electromagnetic proportional control valves 24 and 25 according to an operating command entered by the control lever 43 (bucket control lever 42). The processing then returns.

[0070] If the peak acceleration value of the vehicle body during the determination in step S2 is less than the threshold value (NO in step S2), the processing to correct the input value is not carried out by the operating device. The command calculation unit 102 outputs a control signal to the electromagnetic proportional control valves 24 and 25 according to an operating command entered by the operating lever 43 (blade operating lever 42). The processing returns immediately. Actions and effects

[0071] Although some parts overlap with the description provided above, the characteristic configurations, actions, and effects of the embodiment are summarized as follows.

[0072] As in Fig. 5, Fig. 6 to Fig. As illustrated in Figure 7, the implement control unit 10 sets the operating limit of the bucket 31 in response to the operating command for the bucket 31, based on the detection of the vibration of the vehicle body generated by the operation of the bucket 31. The vibration of the vehicle body is detected by the vibration sensor, and when the intensity of the vibration of the vehicle body reaches or exceeds the threshold value, the sensitivity for actuation of the bucket 31 in response to the operating command issued by the control device is reduced to prevent resonance. By intervening in the operating command according to the vibration state of the vehicle body, the vibration of the vehicle body can be suppressed and thus the vehicle body stabilized.

[0073] The operating command issued by the control device to actuate the bucket 31 can be a bucket lever signal generated by the operator's actuation of the bucket control lever 42. For example, the operating command can be a bucket lever signal when the operator, who is to perform the bucket's vibrating motion, carries out an operation in which they alternately tilt the control lever 43 to the left and to the right. The operating command can also be a bucket lever signal generated by the bucket control lever 42 being shaken by the vibration of the vehicle body. For example, the operating command can be a bucket lever signal when the bucket control lever 42 is shaken by the vibration of the vehicle body caused by the bucket's vibrating motion after the operator has finished the bucket's vibrating motion and has removed their hand from the bucket control lever 42.

[0074] In addition to detecting the vibrations of the vehicle body using the vibration sensor, the vibration period of the vehicle body can also be recorded. By recording the vibration period, it can be determined that the vehicle body is set into vibration due to the shaking motion of the bucket. It should be noted that the shaking motion of the bucket can also be determined from the actuation of the bucket control lever 42.

[0075] As in Fig. 2 and Fig. As illustrated in Figure 5, the vibration sensor can be an accelerometer that detects the acceleration of the vehicle body. Since the acceleration of the vehicle body is an example of a physical quantity representing the vibration of the vehicle body, the vibration can be detected by measuring the acceleration of the vehicle body using the accelerometer. Examples of the physical quantity representing vibration include displacement and velocity, in addition to acceleration. The vibration sensor can include a displacement sensor and / or a velocity sensor, either instead of or in addition to the accelerometer.

[0076] As in Fig. As illustrated in Figure 5, if the condition in which the acceleration of the vehicle body is greater than or equal to the threshold value persists for time t1 or longer, the work device control unit 10 can set a limit for the operation of the bucket 31 in response to the operating command for actuating the bucket 31. If strong vibration of the vehicle body persists for a predetermined period, the operation of the bucket 31 is limited by intervening in the operating command issued by the control device, thus reducing the vibration of the vehicle body and reliably stabilizing the vehicle body.

[0077] As in Fig. As illustrated in Figure 5, if the acceleration of the vehicle body falls below the threshold, the implement control unit 10 can remove the limit for the operation of the bucket 31. By limiting the operation of the bucket 31, the vibration of the vehicle body is reduced and the vehicle body is stabilized. The bucket 31 is then controlled to operate according to the operator's command. The operator actsuates the bucket control lever 42 to cause the bucket 31 to operate according to the command given by the bucket control lever 42. In this way, the responsiveness to the operator's input can be improved.

[0078] As in Fig. 1, Fig. 2 to Fig. As illustrated in Figure 3, the control device can be located in the cabin 5, which the operator enters. Since the cabin 5 is mounted on the vehicle body, vibrations from the vehicle body are transmitted to the control device in the cabin 5. If the control device is shaken by the vibrations of the vehicle body, its movement can serve as an operating command for the operation of the bucket 31. Shaking the bucket 31 can increase the vibration of the vehicle body. By using a configuration where a limit is set for the operation of the bucket 31 when strong vibration of the vehicle body is detected, an amplification of the vehicle body vibration can be avoided, and the vehicle body can be stabilized.

[0079] As in Fig. As illustrated in Figure 3, the operating lever 43 can enclose the enlarged-diameter section 54 at its head end. The operating lever 43, with the enlarged-diameter section 54 at its head end, is likely to be subjected to vibration transmitted from the vehicle body. If strong vibration of the vehicle body is detected, setting a limit for the operation of the bucket 31 in response to an operating command issued by the operating lever 43 to operate the bucket 31 can prevent an amplification of the vehicle body vibration and stabilize the vehicle body.

[0080] As in Fig. As illustrated in Figure 3, the enlarged-diameter section 54 can enclose the switch 55, which can be actuated by the operator. If the enlarged-diameter section 54 encloses the switch 55 at the head end of the control lever 43, the control lever 43 has a top-heavy design, with a large weight distribution at the head end, and is likely to be subjected to vibration when transmitting vehicle body vibration. If strong vehicle body vibration is detected, setting a limit for the operation of the bucket 31 in response to an operating command issued by the control lever 43 to operate the bucket 31 can prevent an amplification of the vehicle body vibration and stabilize the vehicle body.

[0081] As in Fig. 6 and Fig. As illustrated in Figure 7, when vibrations are generated in the vehicle body, the operation of the bucket 31 can consist of a shaking motion of the bucket, in which the bucket 31 is repeatedly actuated in the tipping direction and in the pivoting direction. When the operator performs the shaking motion of the bucket, vibrations in the vehicle body are likely to occur. If the vibration of the vehicle body is strong, an increase in the vibration of the vehicle body can be avoided and the vehicle body stabilized by setting a limit for the operation of the bucket 31 in response to an operating command issued by the control lever 43.

[0082] As in Fig. 6 and Fig.As shown in Figure 7, the implement control unit 10 can set a limit for the amplitude A of the bucket's vibration movement. This reliably prevents an increase in vehicle body vibration and stabilizes the vehicle body.

[0083] In this embodiment, an example is described in which the operating device includes the control lever 43, and the control lever 43 has functions of both the boom control lever 41 and the bucket control lever 42. The boom control lever 41 and the bucket control lever 42 can be configured with separate levers. An operation of tilting the boom control lever 41 in the forward-backward direction can be set as an operation to raise and lower the boom 32, and an operation of tilting the bucket control lever 42 in the forward-backward direction can be set as an operation to rotate the bucket 31.

[0084] The control device does not necessarily have to be located in the cab 5. The control device can be located outside the wheel loader 1. The operator can operate the control device from inside the cab 5 or from outside the wheel loader 1.

[0085] The embodiment described includes an example where the acceleration of the vehicle body in the up-down direction is detected by the IMU 47. The IMU 47 can detect the accelerations of the vehicle body in the forward-backward and forward-backward directions. The detected acceleration values ​​of the vehicle body in the forward-backward and left-right directions can be used to control the bucket operation.

[0086] The attachment at the front of the work unit 3 is not limited to the bucket 31, but can also be another type of attachment. The work machine is not limited to the wheel loader 1, but can also be another type of work machine capable of performing excavation work. Additional remarks

[0087] The above description includes the following additional features. Supplementary Note 1

[0088] Working machine that includes: a vehicle body, a work implement that is attached to the vehicle body in such a way as to enable its operation, and which includes an attachment at one end of the work implement, a control device configured to issue an operating command to cause the attachment to operate, a vibration sensor configured to detect vibrations of the vehicle body, and a control unit configured to set an operating limit for the attachment in response to the operator command, based on the result of the detection of the vibration of the vehicle body generated by the operation of the attachment. Supplementary Note 2

[0089] Working machine according to supplementary note 1, wherein The vibration sensor includes an accelerometer that detects the acceleration of the vehicle body. Supplementary Note 3

[0090] Working machine in accordance with supplementary note 2, wherein The control unit, in response to the operating command, sets an operating limit for the attachment if a condition in which the acceleration is greater than or equal to the threshold persists for a predetermined duration. Supplementary note 4

[0091] Working machine in accordance with Supplementary Note 2 or Supplementary Note 3, wherein The control unit releases the operating limit of the attachment when the acceleration falls below the threshold value. Supplementary note 5

[0092] Working machine according to one of the supplementary notes 1 to 4, wherein the working machine includes a cabin mounted on the vehicle body which allows an operator to enter the cabin, and the operating device is located in the cabin. Supplementary Note 6

[0093] Working machine in accordance with supplementary note 5, wherein the operating device includes an operating lever and The operating lever includes a section with an enlarged diameter at one end of the operating lever. Supplementary note 7

[0094] Working machine in accordance with supplementary note 6, wherein The section with the enlarged diameter includes a switch that can be operated by the user. Supplementary Note 8

[0095] Working machine according to one of the supplementary notes 1 to 7, wherein the attachment includes a shovel and The work consists of a vibrating motion of the shovel, in which the shovel is repeatedly moved in a tipping direction and in a pivoting direction. Supplementary note 9

[0096] Working machine according to supplementary note 8, wherein the control unit sets a limit for the amplitude of the shaking motion of the bucket.

[0097] It is understood that the embodiment disclosed herein is in every respect illustrative and not limiting. The scope of protection of the present invention is defined by the terms of the claims and not by the foregoing description and is intended to include all modifications within the scope and meaning that correspond to the content of the claims. Reference symbol list 1 wheel loader, 2 vehicle body frames, 3 Tools, 5 cabins, 7 Driving device, 10 Work equipment control unit, 11 Engine, 21 Hydraulic pump, 22 Bucket actuation valve, 23 Boom actuating valve, 24 to 27 Electromagnetic proportional control valve, 31 shovels, 32 outriggers, 35 paddle cylinders, 36 boom cylinders, 41 Boom control levers, 42 shovel control levers, 43 operating levers, 44 Boom angle sensor, 45 Blade angle sensor, 46 Boom ground pressure sensor, 47 IMU, 52 Basic section, 53 shaft section, 54 Section with enlarged diameter, 55 switches, 56, 57 Pushbutton switches, 58 toggle switches, 59 electrical cables, 101 Vibration detection unit, 102 Command Calculation Unit, 108 storage units, 109 timekeepers, A Amplitude, t1, t2 time QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2021-43804 A [0002, 0003]

Claims

[1] Working machine, comprising: a vehicle body; a work implement that is attached to the vehicle body in such a way as to enable it to be operated, and which includes an attachment at one end of the work implement; a control device configured to issue an operating command to cause the attachment to operate; a vibration sensor configured to detect vibrations in the vehicle body; and a control unit configured to set an operating limit for the attachment in response to the operator command, based on the result of the detection of the vibration of the vehicle body generated by the operation of the attachment. [2] Working machine according to claim 1, wherein The vibration sensor includes an accelerometer that detects the acceleration of the vehicle body. [3] Working machine according to claim 2, wherein The control unit, in response to the operating command, sets an operating limit for the attachment if a condition in which the acceleration is greater than or equal to the threshold persists for a predetermined duration. [4] Working machine according to claim 3, wherein The control unit releases the operating limit of the attachment when the acceleration falls below the threshold value. [5] Working machine according to claim 1, wherein The working machine includes a cabin mounted on the vehicle body, which allows an operator to enter the cabin, and the operating device is located in the cabin. [6] Working machine according to claim 5, wherein the operating device includes an operating lever and The operating lever includes a section with an enlarged diameter at one end of the operating lever. [7] Working machine according to claim 6, wherein The section with the enlarged diameter includes a switch that can be operated by the user. [8] Working machine according to claim 1, wherein the attachment includes a shovel and The work consists of a vibrating motion of the shovel, in which the shovel is repeatedly moved in a tipping direction and in a pivoting direction. [9] Working machine according to claim 8, wherein The control unit sets a limit for the amplitude of the bucket's vibration movement. [10] Control methods for a working machine, comprising: Receiving the input of an operating command to cause an attachment on the head end of a work implement that is attached to a vehicle body in such a way as to enable it to work; Capturing vibrations of the vehicle body generated by the operation of the attachment and Setting an operating limit for the attachment in response to the operator command based on a result of the detection of the vehicle body vibration.

Images