Working machine and control method for working machine

Abstract

To provide a work machine capable of reducing alarms due to false detection.SOLUTION: A wheel loader 10 includes a vehicle body 1, a rear detection unit 71, and a controller 226. The vehicle body 1 includes: a body frame 2; a front tire 4; a rear tire 7; and a work unit 3 arranged in front of the body frame 2. The rear detection unit 71 detects an obstacle rear the vehicle body 1. The controller 226 is configured to determine that the work unit 3 is currently carrying out raking work based on the operation of the work unit 3 when the vehicle is moving forward and to change the control to prevent approaching the object behind when reversing based on the determination during the raking work.SELECTED DRAWING: Figure 11

Description

Technical Field

[0001] The present invention relates to a work machine and a control method for a work machine.

Background Art

[0002] In a wheel loader which is an example of a work machine, an automatic stop system has been proposed which detects an obstacle behind and automatically stops.

[0003] For example, in Non-Patent Document 1, a stereo camera is installed in a wheel loader, and when an obstacle is recognized during reverse travel, the foot brake is operated.

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in a wheel loader, a scraping-up operation for piling up earth and sand may be performed, and the wheel loader climbs the slope of the earth and sand pile to perform the scraping-up operation. In such a case, in the conventional automatic stop system, when moving backward, the ground is detected as an obstacle and an obstacle alarm is output, which is troublesome for the operator.

[0006] An object of the present disclosure is to provide a working machine and a control method for a working machine capable of reducing alarms due to false detection.

Means for Solving the Problems

[0007] The working machine according to this aspect includes a vehicle body, a rear detection unit, an inclination state detection unit, and a control unit. The rear detection unit detects an object behind the vehicle body. The inclination state detection unit detects the inclination state of the vehicle body. The control unit determines control corresponding to the detection of the rear detection unit based on the inclination state of the vehicle body detected by the inclination state detection unit.

[0008] The working machine according to this aspect includes a vehicle body, a rear detection unit, a first notification unit, and a control unit. The rear detection unit detects an object behind the vehicle body and measures the distance to the object behind the vehicle body. The first notification unit notifies that an object has been detected behind the vehicle body by the rear detection unit. The control unit changes the notification by the first notification unit based on the change in the distance from the vehicle body to the object measured by the rear detection unit.

[0009] The control method for a working machine according to this aspect includes a rear detection step, an inclination state detection step, and a control step. The rear detection step detects an object behind the vehicle body. The inclination state detection step detects the inclination state of the vehicle body. The control step determines control corresponding to the detection of the rear detection step based on the inclination state of the vehicle body detected by the inclination state detection step.

[0010] The control method of the working machine according to this aspect includes a rear detection step and a control step. The rear detection step detects an object behind the vehicle body and measures the distance to the object behind the vehicle body. The control step changes the notification of detecting an object behind the vehicle body based on the change in the measured distance from the vehicle body to the object.

[0011] The working machine according to this aspect includes a vehicle body, a rear detection unit, and a control unit. The vehicle body has a traveling body and a working machine disposed in front of the traveling body. The rear detection unit detects an object behind the vehicle body. The control unit determines whether it is in a scraping-up work state based on the operation of the working machine when the traveling body is moving forward due to the driving of the traveling body, and changes the control for suppressing the approach to the object behind during reverse travel based on the determination of the scraping-up work state.

[0012] The control method of the working machine according to this aspect includes a scraping-up determination step, a rear detection step, and a control step. The scraping-up determination step determines the scraping-up work state based on the operation of the working machine when the traveling body of the vehicle body having the traveling body and the working machine is moving forward due to the driving of the traveling body. The rear detection step detects an object behind the vehicle body. The control step changes the control for suppressing the approach to the object behind during reverse travel based on the determination of the scraping-up work state.

Effect of the Invention

[0013] According to the present disclosure, it is possible to provide a working machine and a control method of the working machine capable of reducing an alarm due to false detection.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Mode for Carrying Out the Invention

[0015] A wheel loader as an example of a working machine according to the present disclosure will be described below with reference to the drawings.

[0016] (Embodiment 1) <Configuration> (Overview of Wheel Loader) FIG. 1 is a schematic diagram showing the configuration of a wheel loader 10 (an example of a work machine) according to the present embodiment. The wheel loader 10 according to the present embodiment includes a vehicle body 1, a body frame 2, a work implement 3, a pair of front tires 4 (an example of wheels), a cab 5, an engine room 6, a pair of rear tires 7 (an example of wheels), and a steering cylinder 9. In the following description, "front", "rear", "right", "left", "up", and "down" indicate directions based on the state of looking forward from the driver's seat. Also, the "vehicle width direction" and the "left-right direction" are synonymous. In FIG. 1, the front-rear direction is indicated by X, the front direction is indicated by Xf, and the rear direction is indicated by Xb. The body frame 2, the front tires 4, and the rear tires 7 correspond to an example of a traveling body.

[0017] The wheel loader 10 performs earthwork loading operations and the like using the work implement 3.

[0018] The body frame 2 is a so-called articulated type and has a front frame 11, a rear frame 12, and a connecting shaft portion 13. The front frame 11 is disposed in front of the rear frame 12. The connecting shaft portion 13 is provided at the center in the vehicle width direction and connects the front frame 11 and the rear frame 12 so as to be swingable relative to each other. The pair of front tires 4 are attached to the left and right of the front frame 11. Also, the pair of rear tires 7 are attached to the left and right of the rear frame 12.

[0019] The work implement 3 is driven by hydraulic oil from a work implement pump (not shown). The work implement 3 is swingably attached to the front portion of the front frame 11. The work implement 3 has a boom 14, a bucket 15, a lift cylinder 16, a bucket cylinder 17 (an example of an actuator), and a bell crank 18 (an example of a sub-link).

[0020] The base end of the boom 14 is rotatably attached to the front part of the front frame 11 by a boom pin 14a. The tip end of the boom 14 is rotatably attached to the rear part of the bucket 15. The rear part of the bucket 15 is on the side opposite to the opening 15b. Between the base end and the tip end of the boom 14, the tip end of the cylinder rod 16a of the lift cylinder 16 is rotatably attached. The cylinder body of the lift cylinder 16 is rotatably attached to the front frame 11.

[0021] One end of the bell crank 18 is rotatably attached to the tip end of the cylinder rod 17a of the bucket cylinder 17. The other end of the bell crank 18 is rotatably attached to the rear part of the bucket 15. The bell crank 18 is rotatably supported by a bell crank support 14d near the center of the boom 14 between both ends. The cylinder body of the bucket cylinder 17 is rotatably attached to the front frame 11. The expansion and contraction force of the bucket cylinder 17 is converted into rotational motion by the bell crank and transmitted to the bucket 15.

[0022] The bucket 15 is rotatably attached to the tip end of the boom 14 by a bucket pin 15a so as to open forward. By the expansion and contraction of the bucket cylinder 17, the bucket 15 rotates with respect to the boom 14 and performs a tilt operation (see arrow J) and a dump operation (see arrow K). Here, the tilt operation of the bucket 15 is an operation in which the opening 15b and the claw 15c of the bucket 15 rotate toward the cab 5 and thus tilt. The dump operation of the bucket 15 is opposite to the tilt operation, and is an operation in which the opening 15b and the claw 15c of the bucket 15 rotate so as to move away from the cab 5 and thus tilt.

[0023] The cab 5 is placed on the rear frame 12, and inside, there are arranged a handle for steering operation, a lever for operating the working machine 3, various display devices, etc. The engine room 6 is on the rear side of the cab 5 and is arranged on the rear frame 12, and the engine 31 is housed therein.

[0024] (Configuration related to the control of the wheel loader) FIG. 2 is a block diagram showing the configuration related to the control of the present disclosure of the wheel loader 10.

[0025] The wheel loader 10 includes a drive system 21, a braking system 22, an operating system 23, a notification system 24, a detection system 25, and a controller 26 (an example of a control unit).

[0026] The drive system 21 drives the wheel loader 10. The braking system 22 performs braking during the travel of the wheel loader 10. The operating system 23 is operated by an operator. The drive system 21 and the braking system 22 operate based on the operation of the operating system 23 by the operator. The notification system 24 notifies the operator based on the operation of the operating system 23 or the detection result by the detection system 25. The detection system 25 detects the inclination state of the vehicle body 1 and an obstacle (an example of an object) behind the vehicle body 1. The controller 26 (an example of a control unit) operates the drive system 21, the braking system 22, and the notification system 24 based on the operation of the operator on the operating system 23 and the detection by the detection system 25.

[0027] (Drive system 21) The drive system 21 includes an engine 31, an HST 32, a transfer 33, an axle 34, and front tires 4 and rear tires 7.

[0028] The engine 31 is, for example, a diesel engine, and the driving force generated by the engine 31 drives the pump 32a of the HST (Hydro Static Transmission) 32.

[0029] The HST32 has a pump 32a, a motor 32b, and a hydraulic circuit 32c that connects the pump 32a and the motor 32b. The pump 32a is a swash plate type variable displacement pump, and the angle of the swash plate can be changed by a solenoid 32d. When the pump 32a is driven by the engine 31, it discharges hydraulic oil. The discharged hydraulic oil is sent to the motor 32b through the hydraulic circuit 32c. The motor 32b is of the swash plate type, and the angle of the swash plate can be changed by a solenoid 32e. The hydraulic circuit 32c has a first drive circuit 32c1 and a second drive circuit 32c2. When hydraulic oil is supplied from the pump 32a to the motor 32b via the first drive circuit 32c1, the motor 32b is driven in one direction (for example, the forward direction). When hydraulic oil is supplied from the pump 32a to the motor 32b via the second drive circuit 32c2, the motor 32b is driven in the other direction (for example, the reverse direction). Note that the discharge direction of the hydraulic oil to the first drive circuit 32c1 or the second drive circuit 32c2 can be changed by the solenoid 32d.

[0030] The transfer 33 distributes the output from the engine 31 to the front and rear axles 34.

[0031] A pair of front tires 4 are connected to the front axle 34 and rotate with the distributed output from the engine 31. Also, a pair of rear tires 7 are connected to the rear axle 34 and rotate with the distributed output from the engine 31.

[0032] (Braking system 22) The braking system 22 has a brake valve 41, a service brake 42, and a parking brake 43.

[0033] The brake valve 41 is, for example, an EPC (Electric Proportional Valve) valve, and by adjusting the opening degree, it can adjust the amount of hydraulic oil sent to the service brake 42.

[0034] The service brake 42 is provided on the axle 34. The service brake 42 is a hydraulic brake. For example, when the opening degree of the brake valve 41 is large, the braking force becomes strong, and when the opening degree of the brake valve 41 is small, the braking force becomes weak.

[0035] As a function of the automatic brake, even when the brake pedal 54 described later is not operated, the brake valve 41 is driven according to an instruction from the controller 26, and the service brake 42 operates.

[0036] The parking brake 43 is provided on the transfer 33. As the parking brake 43, a wet multi-disc brake or a disc brake that can be switched between a braking state and a non-braking state can be used.

[0037] (Operating system 23) The operating system 23 includes an accelerator 51, an FNR lever 52 (an example of an operating member), a parking switch 53, a brake pedal 54, a return switch 55, and an automatic brake release switch 56.

[0038] The accelerator 51 is provided in the cab 5. The operator operates the accelerator 51 to set the throttle opening degree. The accelerator 51 generates an opening degree signal indicating the accelerator operation amount and transmits it to the controller 26. The controller 26 controls the rotational speed of the engine 31 based on the transmitted signal.

[0039] When the accelerator 51 is turned off, the fuel supply to the engine 31 is stopped, the swash plates of the pump 32a and the motor 32b are controlled to become the resistance of running, and a braking force (a weak braking force described later) is generated due to the action of internal inertia.

[0040] The FNR lever 52 is provided in the cab 5. The FNR lever 52 can take a forward, neutral, or reverse position. An operation signal indicating the position of the FNR lever 52 is transmitted to the controller 26, and the controller 26 controls the solenoid 32d to switch between forward and reverse.

[0041] The parking switch 53 is provided in the cab 5 and is a switch that can be switched between on and off states, and transmits a signal indicating its state to the controller 26. The controller 26 sets the parking brake 43 to a braking state or a non-braking state based on the transmitted signal.

[0042] The brake pedal 54 is provided in the cab 5. The brake pedal 54 adjusts the opening degree of the brake valve 41. Also, the brake pedal 54 transmits the operation amount to the controller 26.

[0043] The return switch 55 is operated by the operator to return from the stopped state after the vehicle body 1 has stopped by the automatic brake described later.

[0044] The automatic brake release switch 56 releases the function of the automatic brake and sets it so that the function of the automatic brake does not work.

[0045] (Notification system 24) The notification system 24 includes an alarm device 61 (an example of a first notification unit), a function OFF notification lamp 62 (an example of a second notification unit), and an automatic brake operation notification lamp 63.

[0046] When the alarm device 61 detects an obstacle behind the vehicle body 1 based on the detection of the rear detection unit 71 of the detection system 25 described later, it alarms the operator. The alarm device 61 may have, for example, a lamp and may turn on the lamp. Also, not limited to the lamp, the alarm device 61 may have a speaker and may make a sound. Further, an alarm may be displayed on a display panel such as a monitor.

[0047] When the function of the automatic brake is suppressed or stopped according to the determination of the controller 26, the function OFF notification lamp 62 lights up, for example, to notify the operator. Also, when the automatic brake release switch 56 is operated according to the determination of the operator and the function of the automatic brake is in the OFF state, the function OFF notification lamp 62 lights up, for example, to notify the operator. Further, when the function OFF notification lamp 62 is turned off, it indicates that the function of the automatic brake can be activated. Also, the function OFF notification lamp 62 does not have to be limited to a lamp, and a sound may be emitted. Further, a notification may be displayed on a display panel such as a monitor.

[0048] The automatic brake operation notification lamp 63 notifies the operator that the automatic brake is in an operating state and notifies that a return operation by the return switch 55 is necessary. When the return switch 55 is operated and the automatic brake is released, the automatic brake operation notification lamp 63 turns off.

[0049] Note that the automatic brake operation notification lamp 63 does not have to be limited to a lamp, and a sound may be emitted. Further, a notification may be displayed on a display panel such as a monitor.

[0050] As described above, the means for notifying the operator by the notification system 24 can be appropriately selected, such as a lamp, a sound, and a monitor.

[0051] (Detection system 25) As shown in FIG. 2, the detection system 25 includes a rear detection unit 71 and a vehicle body angle sensor 72 (an example of an inclination state detection unit).

[0052] The rear detection unit 71 detects an obstacle behind the vehicle body 1. The rear detection unit 71 is attached to the rear end of the vehicle body 1 as shown in FIG. 1, for example, but it does not have to be limited to the rear end.

[0053] The rear detection unit 71 has, for example, a millimeter-wave radar. The receiving antenna detects the state in which the radio wave in the millimeter-wave band emitted from the transmitting antenna is reflected by the surface of an obstacle and returns, and can measure the distance to the object. The detection result by the rear detection unit 71 is transmitted to the controller 26, and the controller 26 can detect the presence of an obstacle within a predetermined range during reverse travel. Note that it is not limited to a millimeter-wave radar, and for example, a camera or the like may be used.

[0054] The vehicle body angle sensor 72 detects the inclination state of the vehicle body 1. The vehicle body angle sensor 72 detects whether the vehicle body 1 is in an inclined state by detecting the angle of the vehicle body 1. Note that an IMU (Inertial Measurement Unit) may be used instead of the vehicle body angle sensor 72, or the inclination state of the wheel loader 10 may be determined based on the detection image of a camera installed inside or outside the vehicle body. Also, any configuration that can detect the inclination state of the wheel loader 10 may be used, and it is not limited to these configurations.

[0055] (Controller 26) The controller 26 includes a processor such as a CPU (Central Processing Unit), a main memory including a non-volatile memory such as a ROM (Read Only Memory) and a volatile memory such as a RAM (Random Access Memory), and a storage. The controller 26 reads out the program stored in the storage, expands it in the main memory, and executes predetermined processing according to the program. Note that the program may be distributed to the controller 26 via a network.

[0056] Figure 3 is a block diagram showing the configuration of the controller 26.

[0057] The controller 26 includes an automatic brake control determination unit 81, a brake instruction unit 82, and a notification instruction unit 83. Note that the controller 26 may be provided in plural, not limited to one, and the functions of the automatic brake control determination unit 81, the brake instruction unit 82, and the notification instruction unit 83 may be divided and provided in a plurality of controllers.

[0058] The automatic brake control determination unit 81 makes a determination regarding the control of the automatic brake. The automatic brake control determination unit 81 includes an obstacle determination unit 91, an inclination state determination unit 92, and a determination unit 93.

[0059] The obstacle determination unit 91 determines whether an obstacle exists during reverse travel. The obstacle determination unit 91 detects that the front tire 4 or the rear tire 7 is rotating rearward, or that reverse travel is being performed because the FNR lever 52 is in the reverse position. When the obstacle determination unit 91 receives detection information of an obstacle within a predetermined range from the rear detection unit 71 of the detection system 25 in a state where reverse travel is detected, it determines that an obstacle exists.

[0060] When the inclination state determination unit 92 detects that the inclination angle is equal to or greater than a predetermined angle (for example, 15°) by the vehicle body angle sensor 72, it determines that the vehicle body 1 is disposed on an inclined surface where the ground may be erroneously detected as an obstacle. Note that the inclination angle θ (see FIG. 5 described later) is the angle at which the front side of the wheel loader 10 is lifted with respect to the horizontal.

[0061] The determination unit 93 determines the control of the automatic brake based on the determination result of the obstacle determination unit 91 and the determination result of the inclination state determination unit 92.

[0062] When the determination unit 93 determines that the obstacle determination unit 91 has determined that there is an obstacle during reverse travel and the inclination state determination unit 92 has determined that the inclination angle is less than a predetermined angle, as shown in FIG. 4 described later, the determination unit 93 determines to perform first control of activating the automatic brake and issuing an alarm notifying of the presence of the obstacle. This is because it is determined that the wheel loader 10 is not performing operations such as scooping up since the inclination angle is detected to be less than the predetermined angle, and the detection of the obstacle is not a false detection.

[0063] Further, when the determination unit 93 determines that the obstacle determination unit 91 has determined that there is an obstacle during reverse travel, but the inclination state determination unit 92 has determined that the inclination angle is greater than or equal to the predetermined angle, the determination unit 93 determines to perform second control of not activating the automatic brake and notifying that the function of the automatic brake is stopped. This is because it is determined that the wheel loader 10 is performing operations such as scooping up as shown in FIG. 5 described later since the inclination angle is detected to be greater than or equal to the predetermined angle, and the ground may be misdetected as an obstacle.

[0064] The brake instruction unit 82 controls the automatic brake based on the determination of either the first control or the second control by the determination unit 93. The automatic brake in this specification is to automatically activate the braking force on the vehicle body 1 based on the determination result of the obstacle determination unit 91 and the determination result of the inclination state determination unit 92, and is not limited only to the braking force by the service brake 42 as described later.

[0065] The notification instruction unit 83 gives an operation instruction to the alarm device 61 or the function OFF notification lamp 62 based on the determination of either the first control or the second control by the determination unit 93.

[0066] When the determination unit 93 determines to perform the first control, the brake instruction unit 82 stops the fuel supply to the engine 31 by turning off the accelerator 51. Then, the brake instruction unit 82 drives the service brake 42 by operating the brake valve 41 to stop the vehicle body 1. The notification instruction unit 83 activates the alarm device 61 to notify the operator of the presence of the obstacle and the activation of the automatic brake.

[0067] Figure 4 is a diagram showing a state in which an obstacle S is detected during backward movement and the vehicle body 1 is stopped. In the first control, the service brake 42 is operated with a preset braking force (which can also be said to be a braking force) so that the vehicle body 1 stops in front of the obstacle S, and the vehicle body 1 is stopped. In Figure 4, the stopped vehicle body 1 is indicated by a two-dot chain line.

[0068] Note that the automatic brake by the set braking force does not necessarily have to brake the vehicle body 1 by the service brake 42 as described above, and the parking brake 43 may be operated. In this case, when the determination unit 93 determines to perform the first control, the brake instruction unit 82 stops the fuel supply to the engine 31 by turning off the accelerator 51. Then, the brake instruction unit 82 controls the parking brake 43 to brake the vehicle body 1.

[0069] When the determination unit 93 determines to perform the second control, the notification instruction unit 83 performs control to turn on the function OFF notification lamp 62, and does not cause the brake valve 41 to operate by the brake instruction unit 82 and the alarm device 61 to operate by the notification instruction unit 83.

[0070] Figure 5 is a diagram showing a state in which the wheel loader 10 is performing a scraping operation. As shown in Figure 5, a mound M of earth and sand is formed on the ground G, and the wheel loader 10 is arranged on the slope i thereof. During scraping, since the wheel loader 10 goes up and down the slope i, it detects the ground G as an obstacle S every time it moves backward. Therefore, in the present embodiment, when the angle θ detected by the vehicle body angle sensor 72 is equal to or greater than a predetermined angle, control is performed so that even if an obstacle is detected, no automatic brake is performed and the alarm device 61 is not operated. The inclination angle θ is, for example, the angle formed by a line L connecting the axes of the front tires 4 and the rear tires 7 and the horizontal line H.

[0071] Thereby, false detection can be suppressed, and the working efficiency can be improved.

[0072] <Operation> Next, the control operation of the wheel loader 10 of the present embodiment will be described.

[0073] FIG. 6 is a flowchart showing the control operation of the wheel loader 10 of the present embodiment.

[0074] First, in step S10 (an example of a backward detection step), the obstacle determination unit 91 of the controller 26 determines whether an obstacle has been detected when the vehicle body 1 is moving backward. The obstacle determination unit 91 determines that the vehicle body 1 is in a backward state based on the fact that the front tire 4 or the rear tire 7 is rotating backward, or the FNR lever 52 is in the backward position. When the obstacle determination unit 91 receives detection information of an obstacle within a predetermined range from the rear detection unit 71 of the detection system 25 in a state where it has detected that backward movement is being performed, it determines that an obstacle exists.

[0075] In step S10, if it is not determined that an obstacle exists, in step S14, the controller 26 ends the control without activating the automatic brake. In step S14, since the presence of an obstacle has not been detected, the warning device 61 also does not issue a warning.

[0076] In step S11 (an example of an inclination state detection step), when the inclination angle θ is determined by the inclination state determination unit 92 to be less than a predetermined threshold value (for example, 15 degrees), the determination unit 93 determines to perform the first control, and the first control is performed in step S12.

[0077] In the first control in step S12 (an example of a control step), in the controller 26, the brake instruction unit 82 stops the fuel supply to the engine 31. Then, the brake instruction unit 82 operates the brake valve 41 to drive the service brake 42 to stop the vehicle body 1. The notification instruction unit 83 activates the warning device 61 to notify the operator of the presence of an obstacle and the activation of the automatic brake, and the control ends.

[0078] On the other hand, in step S11, when it is determined that the inclination angle θ is equal to or greater than a predetermined threshold value, the determination unit 93 determines to perform the second control, and the second control is performed in step S13.

[0079] In the second control in step S13 (an example of a control step), the notification instruction unit 83 does not activate the alarm device 61, but turns on the function OFF notification lamp 62, and the control ends. Note that the controller 26 does not control the brake valve 41.

[0080] Thereby, in the case of an inclination state where the ground G is detected as an obstacle, the function of the automatic brake and the alarm device 61 can be stopped.

[0081] Therefore, false detection alarms can be reduced.

[0082] In addition, since the function of the automatic brake can be stopped, it is possible to detect the ground during the scraping operation and prevent the vehicle from being unable to descend from the earth and sand pile M.

[0083] Also, for example, after the first control is performed in step S12 and the control ends, the control is started again. Next, if no obstacle is detected in step S10, the operation of the brake is stopped in step S14. In this way, appropriate automatic brake control can be performed even when the obstacle no longer exists during reverse travel. The same applies when an obstacle appears during reverse travel.

[0084] (Embodiment 2) Next, the wheel loader 10 according to Embodiment 2 of the present disclosure will be described.

[0085] <Configuration> The wheel loader 10 according to the second embodiment does not have the vehicle body angle sensor 72 as compared with the first embodiment.

[0086] FIG. 7 is a block diagram showing the configuration of the drive system, braking system, operation system, notification system, and controller of the wheel loader according to the second embodiment. FIG. 8 is a block diagram showing the configuration of the controller 126 shown in FIG. 7.

[0087] The detection system 125 of the second embodiment has a rear detection unit 71 but does not have a vehicle body angle sensor 72.

[0088] Also, the automatic brake control determination unit 181 of the controller 126 in the second embodiment has a distance change determination unit 94 instead of the inclination state determination unit 92 of the automatic brake control determination unit 81 in the first embodiment.

[0089] The distance change determination unit 94 of the second embodiment determines the change in the distance to the object detected using the detection result from the rear detection unit 71. By using, for example, a millimeter-wave radar for the rear detection unit 71, the distance to the object can be measured.

[0090] Although the scooping operation of the wheel loader 10 has been described with reference to FIG. 5, in the scooping operation, the up and down movement of the earth and sand pile M is performed. FIG. 9 is a view showing the wheel loader 10 in a state lowered from the state of FIG. 5. In FIG. 5, the distance from the rear detection unit 71 to the ground G is indicated by d1, and in FIG. 9, the distance from the rear detection unit 71 to the ground G is indicated by d2. As shown in FIGS. 5 and 9, when the wheel loader 10 descends the earth and sand pile M, the inclination becomes gentle, so the distance from the rear detection unit 71 to the ground G becomes longer as shown by d1 < d2.

[0091] The distance change determination unit 94 of the present embodiment determines whether the distance to the object determined as an obstacle by the obstacle determination unit 91 becomes longer during reverse travel.

[0092] When the obstacle determination unit 91 determines that there is an obstacle during backward movement and determines that the distance to the obstacle is increasing during backward movement, the determination unit 93 decides to perform second control to notify that the automatic brake is not activated and the function of the automatic brake is stopped. This is because, since the distance to the obstacle is increasing during backward movement, it can be determined that the wheel loader 10 is performing an operation such as scooping up, and the ground is being erroneously detected as an obstacle. Note that it is not always necessary to notify that the function of the automatic brake is stopped.

[0093] Also, when the obstacle determination unit 91 determines that there is an obstacle during backward movement and determines that the distance to the obstacle is not increasing during backward movement, the determination unit 93 decides to perform first control to activate the automatic brake and issue an alarm notifying of the presence of the obstacle. This is because, since the distance to the obstacle is not increasing, it can be determined that the wheel loader 10 is not performing an operation such as scooping up, and the detection of the obstacle is not an erroneous detection.

[0094] <Operation> Next, the control operation of the wheel loader 10 according to the second embodiment will be described.

[0095] FIG. 10 is a flowchart showing the control operation of the wheel loader 10 according to the second embodiment.

[0096] First, in step S10 (an example of a rear detection step), the obstacle determination unit 91 of the controller 26 determines whether an obstacle has been detected when the vehicle body 1 is moving backward. The obstacle determination unit 91 determines that the vehicle body 1 is in a backward movement state when the front tire 4 or the rear tire 7 is rotating backward, or when the FNR lever 52 is in the reverse position. When the obstacle determination unit 91 receives detection information of an obstacle within a predetermined range from the rear detection unit 71 of the detection system 125 in a state where it has detected that backward movement is being performed, it determines that an obstacle exists. In step S10, if it is not determined that an obstacle exists, in step S14, the controller 26 ends the control without activating the automatic brake. In step S14, since the presence of an obstacle has not been detected, the warning device 61 does not issue a warning either.

[0097] Next, in step S111 (an example of a distance change determination step), the distance change determination unit 94 determines whether the distance to the obstacle is increasing when moving backward as determined by the obstacle determination unit 91. The distance change determination unit 94 compares the distance to the obstacle at a predetermined first time point with the distance to the obstacle at a second time point after the first time point, and determines that the distance to the obstacle is increasing when the distance at the second time point is greater than the distance at the first time point.

[0098] If it is determined in step S111 by the inclination state determination unit 92 that the distance to the obstacle is not increasing, the determination unit 93 determines to perform the first control, and the first control is performed in step S12.

[0099] In the first control in step S12 (an example of a control step), in the controller 26, the brake instruction unit 82 stops the fuel supply to the engine 31. Then, the brake instruction unit 82 operates the brake valve 41 to drive the service brake 42 to stop the vehicle body 1. The notification instruction unit 83 activates the warning device 61 to notify the operator of the presence of the obstacle and the activation of the automatic brake, and the control ends.

[0100] On the one hand, in step S111, when the distance change determination unit 94 determines that the distance from the obstacle is increasing, the determination unit 93 determines to perform the second control, and the second control is performed in step S13.

[0101] In the second control in step S13 (an example of a control step), the notification instruction unit 83 does not activate the alarm device 61, but turns on the function OFF notification lamp 62, and the control ends. Note that the controller 26 does not control the brake valve 41.

[0102] Thereby, it can be determined that the ground G is detected as an obstacle, and the functions of the automatic brake and the alarm device 61 can be stopped.

[0103] (Embodiment 3) Next, the wheel loader 10 according to Embodiment 3 of the present disclosure will be described.

[0104] In Embodiment 1, when the inclination angle is equal to or greater than a predetermined threshold value, it is determined that the scooping operation is being performed, and the second control is performed. However, in Embodiment 3, it is determined that the scooping operation is being performed based on the operation of the work implement 3 or the like.

[0105] <Configuration> FIG. 11 is a block diagram showing the configuration related to the control of the wheel loader 10 according to Embodiment 3 of the present disclosure.

[0106] In the drive system 221 of the wheel loader 10 according to Embodiment 3 of the present disclosure, in addition to the configuration of the drive system 21 of Embodiment 1, a cylinder drive unit 35 is further provided.

[0107] The cylinder drive unit 35 has a power take-off unit 35a, a work implement pump 35b, and a control valve 35c. The power take-off unit 35a is a PTO (Power Take Off). For example, in a state where the vehicle body 1 is stopped, the output from the engine 31 is taken out and transmitted to the work implement pump 35b. The work implement pump 35b is driven by the power of the engine 31 and discharges hydraulic oil to the control valve 35c. The control valve 35c supplies the hydraulic oil supplied from the work implement pump 35b to the lift cylinder 16 (an example of a boom cylinder) and the bucket cylinder 17 based on a command from the controller 26.

[0108] Unlike the detection system 225 of the wheel loader 10 in the first embodiment, the detection system 225 of the wheel loader 10 in the third embodiment does not have a vehicle body angle sensor 72, and in addition to the rear detection unit 71, it has a boom angle sensor 73 (an example of a work implement height detection unit) and a boom bottom pressure sensor 74.

[0109] The boom angle sensor 73 detects the angle of the boom 14 and outputs the detected value to a controller 226 (an example of a control unit). The boom angle sensor 73 can be configured by a potentiometer and is arranged, for example, at the boom pin 14a.

[0110] As shown in FIG. 1, the angle of the boom 14 is the angle θ of a straight line Lb extending from the center of the boom pin 14a toward the center of the bucket pin 15a with respect to a horizontal line Lh extending forward from the center of the boom pin 14a. When the straight line Lb is horizontal, the boom angle is set to 0°. When the straight line Lb is above the horizontal line Lh, the angle θ of the boom 14 is set to a positive value. When the straight line Lb is below the horizontal line Lh, the angle θ of the boom 14 is set to a negative value.

[0111] Note that the boom angle sensor 73 may be a stroke sensor provided on the lift cylinder 16.

[0112] The boom bottom pressure sensor 74 is attached to the bottom side of the lift cylinder 16. Pressure is applied to the bottom side of the lift cylinder 16, and this pressure causes the cylinder to extend and the boom 14 to rise. The boom bottom pressure sensor 74 detects the pressure (bottom pressure) of the hydraulic oil in the oil chamber on the cylinder bottom side of the lift cylinder 16. The boom bottom pressure sensor 74 transmits the detected bottom pressure to the controller 226.

[0113] Figure 12 is a block diagram showing the configuration of the controller 226.

[0114] Unlike the controller 26 in Embodiment 1, the controller 226 has a scraping determination unit 95 instead of the inclination state determination unit 92. The scraping determination unit 95 determines whether the work content of the wheel loader 10 during forward movement is a scraping operation.

[0115] The scraping determination unit 95 determines whether it is in an excavation work state during forward movement, and after determining that the excavation work state is maintained, determines whether it is in a scraping work state.

[0116] Figure 13 is a diagram showing the state transition of the work content. The scraping determination unit 95 determines the excavation work state W1 and the state W2 other than the excavation work.

[0117] The scraping determination unit 95 determines that it is in the excavation work state W1 when conditions A and B are satisfied during forward movement.

[0118] The scraping determination unit 95 determines that the vehicle body 1 is traveling forward (forward state) either by the front tire 4 or the rear tire 7 rotating forward or the FNR lever 52 being in the forward position.

[0119] Condition (A) is that the boom bottom pressure, which is the detected value by the boom bottom pressure sensor 74, satisfies being equal to or greater than the first threshold value. The first threshold value is stored in the controller 226. When the boom bottom pressure becomes equal to or greater than the predetermined threshold value, it can be known that pressure has been applied to the lift cylinder 16. That is, during excavation or the like, pressure is applied to the lift cylinder 16 by loading the bucket 15 with earth and sand, so it is possible to determine whether it is in the excavation work state by detecting the boom bottom pressure.

[0120] Condition (B) is that the angle θ of the boom 14, which is the detected value by the boom angle sensor 73, satisfies being equal to or less than the second threshold value. During excavation, since the angle θ of the boom 14 is positioned below the horizontal state, the second threshold value is preferably a negative value. The second threshold value is stored in the controller 226.

[0121] That is, when a pressure equal to or greater than a predetermined first threshold value is loaded on the lift cylinder 16 and the angle θ of the boom 14 becomes lower than or equal to a predetermined second threshold value, it is determined that the state of the wheel loader 10 is the excavation work state W1. When the scraping determination unit 95 determines that it is in the excavation work state W1, it sets the excavation flag to ON and sets the boom pressure drop flag to OFF.

[0122] Next, the scraping determination unit 95 determines whether it is in the scraping work state W3 or a state other than the scraping work W4 in the excavation work state W1. When the excavation flag is ON and the condition (C) is satisfied, the scraping determination unit 95 determines that it is in the scraping work state W3, and when the condition (C) is not satisfied, it determines that it is in a state other than the scraping work W4.

[0123] Condition (C) is satisfied when the angle θ of the boom 14, which is the detected value by the boom angle sensor 73, is greater than the third threshold value. The third threshold value is, for example, a negative value. The third threshold value is set to be larger than the second threshold value. The third threshold value is stored in the controller 226. Note that the second threshold value indicates when the position of the bucket 15 is close to the tire contact ground surface. The second threshold value can be set to, for example, -40°. Also, the third threshold value indicates when the boom 14 is positioned at an intermediate level between the horizontal state and the state of the second threshold value. The third threshold value can be set to, for example, -20°. The third threshold value and the second threshold value are set such that the boom 14 at the third threshold value is in a state of rotating upward compared to the boom 14 at the second threshold value.

[0124] Note that although conditions (B) and (C) are set based on the magnitude of the angle of the boom 14, it is not limited to this, and the position of the bucket 15 can be detected and set based on its height. The position of the bucket 15 can be detected by, for example, a camera provided on the cab 5 or the like. Also, the third threshold value and the second threshold value are set such that the height of the bucket 15 at the third threshold value is higher than the height of the bucket 15 at the second threshold value.

[0125] In this way, based on the height of the working machine 3, conditions (B) and (C) can be set, and the height of the working machine 3 at the third threshold value can be set to be higher than the height of the working machine 3 at the second threshold value.

[0126] When the scraping determination unit 95 determines that it is in the scraping operation state W3, it sets the scraping flag. Also, when the scraping determination unit 95 determines that the excavation flag is ON and condition (C) is not satisfied, it sets the scraping flag to OFF.

[0127] Since the boom 14 is positioned upward during scraping compared to normal excavation, in the excavation operation state W1, by detecting the angle θ of the boom 14, the scraping operation state W3 and the state W4 other than the scraping operation can be discriminated.

[0128] In addition, when the scraping-up determination unit 95 satisfies condition (D) or condition (E) in a state where the excavation flag is ON, the excavation flag is set to OFF on the assumption that the wheel loader 10 is in a state W2 other than the excavation operation.

[0129] Condition (D) is that the boom bottom pressure drop flag is ON. When the detected value by the boom bottom pressure sensor 74 is smaller than the boom bottom pressure as a threshold value preset based on the angle θ of the boom 14 for a predetermined time, the boom bottom pressure drop flag is set to ON. Here, the boom bottom pressure as a threshold value preset based on the angle θ of the boom 14 is stored in the controller 226.

[0130] In this way, when the boom bottom pressure becomes smaller than the threshold value set based on the boom angle for a predetermined time, the scraping-up determination unit 95 sets the boom pressure drop flag to ON, determines that the state has transitioned to the state W2 other than the excavation operation, and sets the excavation flag to OFF.

[0131] Condition (E) is that the position of the FNR lever 52 is arranged at a position other than forward (F) (reverse (N) or neutral (N)). When the scraping-up determination unit 95 is not moving forward, it determines that it is in the state W2 other than the excavation operation and sets the excavation flag to OFF.

[0132] As described above, when the scraping-up determination unit 95 determines that it is in the excavation operation state W1 by satisfying condition (A) and condition (B), and further satisfies condition (C) in a state where that determination is maintained, the wheel loader 10 is determined to be in the scraping-up operation state W3, and the scraping-up flag is set to ON.

[0133] The determination unit 93 determines the control of the automatic brake based on the determination result of the obstacle determination unit 91 and the determination result of the scraping-up determination unit 95.

[0134] When the determination unit 93 determines that the scraping-up determination unit 95 is not performing the scraping-up operation (in FIG. 12, the state W2 other than the excavation operation or the state W4 other than the scraping-up operation), and the obstacle determination unit 91 determines that there is an obstacle during backward movement, it is determined to perform the first control of activating the automatic brake and issuing an alarm notifying the presence of the obstacle. This is because it can be determined that the wheel loader 10 is not performing the scraping-up operation and the detection of the obstacle is not a false detection.

[0135] Also, when the determination unit 93 determines that the scraping-up determination unit 95 is in the scraping-up operation state W3, and then the obstacle determination unit 91 determines that there is an obstacle during backward movement, it is determined to perform the second control of not activating the automatic brake and notifying that the function of the automatic brake is stopped. This is because it can be determined that the wheel loader 10 is performing the scraping-up operation and the ground is misdetected as an obstacle.

[0136] <Operation> Next, the control operation of the wheel loader 10 according to the third embodiment will be described.

[0137] FIG. 14 is a flowchart showing the control operation of the wheel loader 10 according to the third embodiment.

[0138] First, in step S210, the scraping-up determination unit 95 determines whether the vehicle body 1 is moving forward. The scraping-up determination unit 95 determines that the wheel loader 10 is traveling forward (in the forward state) based on either the front tire 4 or the rear tire 7 rotating forward or the FNR lever 52 being in the forward position.

[0139] If it is determined in step S210 that the vehicle is in the forward state, then in step S220, the scraping-up determination unit 95 determines whether the wheel loader 10 is in the excavation operation state W1. The scraping-up determination unit 95 determines that the wheel loader 10 is in the excavation operation state W1 when the conditions (A) based on the boom bottom pressure and the conditions (B) based on the boom angle are satisfied.

[0140] In step S220, when it is determined that the conditions (A) and (B) are satisfied and the excavation operation state is W1, the scraping determination unit 95 sets the excavation flag to ON, and the control proceeds to step S230.

[0141] In step S230, the scraping determination unit 95 determines whether the wheel loader 10 is in the scraping operation state W3. The scraping determination unit 95 determines that it is in the scraping operation state W3 when the condition (C) based on the boom angle is satisfied with the excavation flag set to ON.

[0142] In step S230, when it is determined that the condition (C) is satisfied and the scraping operation state is W3, the scraping determination unit 95 sets the scraping flag to ON, and the control proceeds to step S240.

[0143] In step S240, the obstacle determination unit 91 determines whether the wheel loader 10 is in the reverse state. The obstacle determination unit 91 determines that the wheel loader 10 is traveling backward (in the reverse state) either by the front tire 4 or the rear tire 7 rotating backward or the FNR lever 52 being in the reverse position.

[0144] In step S240, when it is determined that it is in the reverse state, the control proceeds to step S250.

[0145] In step S250, the obstacle determination unit 91 determines the presence of an obstacle. When the obstacle determination unit 91 receives the detection information of an obstacle within a predetermined range from the rear detection unit 71 of the detection system 225, it determines that an obstacle exists.

[0146] In step S250, when it is determined that an obstacle exists, the decision unit 93 decides to perform the second control, and the second control is performed in step S260.

[0147] In the second control in step S260 (an example of a control step), the notification instruction unit 83 does not activate the alarm device 61, but lights the function OFF notification lamp 62, and the control ends. Note that the controller 26 does not control the brake valve 41.

[0148] Thereby, it can be determined that the ground G is detected as an obstacle, and the function of the automatic brake and the alarm device 61 can be stopped.

[0149] On the other hand, in step S210, if it is not determined that the vehicle is in the forward state, the control proceeds to step S270. In step S270, the obstacle determination unit 91 determines whether the wheel loader 10 is in the reverse state. The obstacle determination unit 91 determines that the wheel loader 10 is traveling backward (in the reverse state) based on either the front tire 4 or the rear tire 7 rotating backward or the FNR lever 52 being in the reverse position.

[0150] In step S270, if it is determined that the vehicle is in the reverse state, the control proceeds to step S280. In step S280, the obstacle determination unit 91 determines the presence of an obstacle. When the obstacle determination unit 91 receives detection information of an obstacle within a predetermined range from the rear detection unit 71 of the detection system 225, it determines that an obstacle exists.

[0151] In step S280, if it is determined that an obstacle exists, the determination unit 93 determines to perform the first control, and the first control is performed in step S290.

[0152] In the first control in step S280 (an example of a control step), in the controller 26, the brake instruction unit 82 stops the fuel supply to the engine 31. Then, the brake instruction unit 82 operates the brake valve 41 to drive the service brake 42 to stop the vehicle body 1. The notification instruction unit 83 activates the alarm device 61 to notify the operator of the presence of an obstacle and the activation of the automatic brake, and the control ends.

[0153] In addition, in step S220, if it is not determined that it is an excavation operation, the control ends without operating the braking system 22 and the notification system 24. In step S230, if it is not determined that it is a scraping-up operation, the control ends without operating the braking system 22 and the notification system 24. In step S240, if it is not determined that it is in a reverse state, the control ends without operating the braking system 22 and the notification system 24. In step S250, if no obstacle is detected, the control ends without operating the braking system 22 and the notification system 24.

[0154] Also, in step S270, if it is not determined that it is in a reverse state, the control ends without operating the braking system 22 and the notification system 24. Also, in step S280, if no obstacle is detected, the control also ends without operating the braking system 22 and the notification system 24.

[0155] <Feature> (1) The wheel loader 10 (an example of a work machine) of the present embodiment includes a vehicle body 1, a rear detection unit 71, a vehicle body angle sensor 72 (an example of an inclination state detection unit), and a controller 26 (an example of a control unit). The rear detection unit 71 detects an obstacle (an example of an object) behind the vehicle body 1. The vehicle body angle sensor 72 detects the inclination state of the vehicle body 1. The controller 26 determines control corresponding to the detection of the rear detection unit 71 based on the inclination state of the vehicle body 1 detected by the vehicle body angle sensor 72.

[0156] Thereby, for example, when the vehicle body 1 is disposed at a place where it is inclined during a scraping-up operation or the like, it is possible to prevent the ground G from being detected as an obstacle, so that false detection of an obstacle can be prevented. Note that the control corresponding to the detection of the rear detection unit 71 can also be said to be control for suppressing approach to an obstacle S (an example of an object) behind during reverse travel.

[0157] (2) The wheel loader 10 (an example of a working machine) of the present embodiment further includes an alarm device 61 (an example of a first notification unit). The alarm device 61 notifies that an obstacle (an example of an object) has been detected behind the vehicle body 1 by the rear detection unit 71. The control corresponding to the rear detection by the rear detection unit 71 includes stopping the notification by the alarm device 61.

[0158] This makes it possible to prevent the alarm from being issued by erroneously detecting the ground G as an obstacle and notifying the presence of the obstacle.

[0159] (3) The wheel loader 10 (an example of a working machine) of the present embodiment includes a vehicle body 1, a rear detection unit 71, an alarm device 61 (an example of a first notification unit), and a controller 126 (an example of a control unit). The rear detection unit 71 detects an object behind the vehicle body 1 and measures the distance to the object behind the vehicle body 1. The alarm device 61 notifies that an object has been detected behind the vehicle body 1 by the rear detection unit 71. The controller 126 changes the notification by the alarm device 61 based on the change in the distance from the vehicle body 1 to the object measured by the rear detection unit 71.

[0160] This makes it possible to prevent the wheel loader 10 from detecting the ground G as an obstacle when performing, for example, a scraping operation, etc., so that false detection of an obstacle can be prevented. Therefore, the alarm of the alarm device 61 can be stopped, for example, and the alarm due to false detection can be reduced.

[0161] (4) In the wheel loader 10 (an example of a working machine) of the present embodiment, the rear detection unit 71 detects an object behind the vehicle body 1 when the vehicle body 1 is moving backward. The rear detection unit 71 detects the backward movement by the front tire 4 or the rear tire 7 (an example of a wheel) provided on the vehicle body 1 rotating backward or the FNR lever 52 (an example of an operation member) that can set the forward or backward movement of the vehicle body 1 being set to the backward position.

[0162] Accordingly, it is possible to detect that the vehicle body 1 is moving backward.

[0163] (5) In the wheel loader 10 (an example of a working machine) of the present embodiment, the control corresponding to the detection by the rear detection unit 71 includes an automatic brake that automatically brakes the vehicle body 1 when the rear detection unit 71 detects an obstacle (an example of an object), and the stop of the automatic brake.

[0164] This can prevent the automatic brake from being activated and stopping the vehicle body 1 by erroneously detecting the ground G as an obstacle S.

[0165] (6) In the wheel loader 10 (an example of a working machine) of the present embodiment, when the controller 26 (an example of a control unit) detects an obstacle (an example of an object) behind the vehicle body 1 by the rear detection unit 71, when the inclination of the vehicle body 1 is less than a predetermined threshold value, the alarm device 61 notifies of the detection of the obstacle, and when the inclination of the vehicle body 1 is greater than or equal to the predetermined threshold value, the alarm device 61 (an example of a first notification unit) stops the notification.

[0166] This makes it possible to prevent erroneously detecting the ground G as an obstacle and issuing an alarm when, for example, the vehicle body 1 is disposed at a place where it is inclined during a scooping operation or the like.

[0167] (7) In the wheel loader 10 (an example of a working machine) of the present embodiment, when the controller 26 (an example of a control unit) detects an obstacle (an example of an object) behind the vehicle body 1 by the rear detection unit 71, when the inclination of the vehicle body 1 is less than a predetermined threshold value, the automatic brake is activated, and when the inclination of the vehicle body 1 is greater than or equal to the predetermined threshold value, the automatic brake is stopped.

[0168] This can prevent the automatic brake from being activated and stopping the vehicle body 1 when, for example, the vehicle body is disposed at a place where it is inclined during a scooping operation or the like.

[0169] (8) The wheel loader 10 (an example of a working machine) according to this embodiment further includes a function OFF notification lamp 62 (an example of a second notification unit). The function OFF notification lamp 62 notifies the operator of the stop of the automatic brake. When the controller 26 (an example of a control unit) suppresses or stops the automatic brake, the function OFF notification lamp 62 notifies the operator. Thereby, the operator can be made to recognize that the suppression or stop of the automatic brake is being performed.

[0170] (9) In the wheel loader 10 (an example of a working machine) according to this embodiment, the predetermined threshold value of the inclination is 15°.

[0171] Thereby, the vehicle body 1 can detect that it is disposed on a steep slope such as a construction site.

[0172] (10) In the wheel loader 10 (an example of a working machine) according to this embodiment, when the distance between the object at the second time point after the first time point is larger than the distance between the object at the first time point, the controller 126 (an example of a control unit) changes the notification by the alarm device 61 (an example of a first notification unit).

[0173] When the detected distance from the object thus increases, it can be determined that the wheel loader 10 is performing, for example, a scooping operation.

[0174] (11) In the wheel loader 10 (an example of a working machine) according to this embodiment, when the controller 126 (an example of a control unit) changes the notification by the alarm device 61 (an example of a first notification unit), the controller 126 stops the automatic brake that automatically brakes the vehicle body 1.

[0175] Thereby, it is possible to prevent the automatic brake from operating due to erroneously detecting the ground G as the obstacle S and stopping the vehicle body 1.

[0176] (12) The wheel loader 10 (an example of a working machine) of the present embodiment includes a vehicle body frame 2 (an example of a main body frame), a boom 14, a bucket 15, a bucket cylinder 17 (an example of an actuator), and a bell crank 18 (an example of a sub-link). The boom 14 is swingably attached to the front portion of the vehicle body frame 2. The bucket 15 is connected to the boom 14 so that an opening 15b is disposed forward and is driven with respect to the boom 14. The bucket cylinder 17 drives the bucket 15. The bell crank 18 is attached to the boom 14 and transmits the driving force of the bucket cylinder 17 to the bucket 15.

[0177] Accordingly, in the wheel loader 10 having a front loading configuration, when performing a scraping operation or the like, it is possible to reduce an alarm due to false detection in which the alarm device 61 is activated by falsely detecting the ground G as an obstacle S.

[0178] (13) The control method of the wheel loader 10 (an example of a working machine) of the present embodiment includes a step S10 (an example of a rear detection step), a step S11 (an example of an inclination state detection step), and steps S12 and S13 (an example of a control step). The step S10 detects an obstacle (an example of an object) behind the vehicle body 1. The step S11 detects the inclination state of the vehicle body 1. The steps S12 and S13 determine control corresponding to the detection in the step S10 based on the inclination state of the vehicle body 1 detected in the step S11.

[0179] Accordingly, for example, when the vehicle body 1 is disposed at an inclined location during a scraping operation or the like, it is possible to prevent the ground G from being detected as an obstacle, and thus false detection of an obstacle can be prevented.

[0180] (14) The control method of the wheel loader 10 (an example of a work machine) according to this embodiment includes a step S10 (an example of a rear detection step), a step S111 (an example of a distance change determination step), and steps S12 and S13 (an example of a control step). Step S10 detects an obstacle (an example of an object) behind the vehicle body 1. Step S11 determines the change in the distance measured from the vehicle body 1 to the obstacle. Steps S12 and S13 change the notification of detecting an object behind the vehicle body 1 based on the change in the distance detected in step S111.

[0181] (15) The wheel loader 10 (an example of a work machine) according to this embodiment includes a vehicle body 1, a rear detection unit 71, and a controller 226 (an example of a control unit). The vehicle body 1 has a vehicle body frame 2, front tires 4, and rear tires 7 (an example of a traveling body), and a work implement 3 disposed in front of the vehicle body frame 2. The rear detection unit 71 detects an obstacle (an example of an object) behind the vehicle body 1. The controller 226 (an example of a control unit) determines that it is in a scraping operation state based on the operation of the work implement 3 during forward movement due to the drive of the traveling body, and changes the control to suppress approaching an object behind during backward movement based on the determination of the scraping operation state.

[0182] Thereby, when the vehicle body 1 is disposed at a location inclined during the scraping operation, it is possible to prevent the ground G from being detected as an obstacle, so that false detection of an obstacle can be prevented.

[0183] (16) In the wheel loader 10 (an example of a working machine) according to this embodiment, the working machine 3 includes a boom 14, a bucket 15, and a lift cylinder 16 (an example of a boom cylinder). The boom 14 is swingably attached to the front portion of the vehicle body frame 2. The bucket 15 is connected to the boom 14 such that an opening is disposed forward, and is driven with respect to the boom 14. The lift cylinder 16 drives the boom 14. The wheel loader 10 further includes a boom bottom pressure sensor 74 and a boom angle sensor 73 (an example of a working machine height detection unit). The boom bottom pressure sensor 74 detects the bottom pressure of the lift cylinder 16. The boom angle sensor 73 detects the angle θ of the boom 14. The controller 226 determines whether or not it is in a scraping operation state based on the bottom pressure of the lift cylinder 16 and the height of the working machine 3.

[0184] In this way, by detecting the angle θ of the boom 14 and the bottom pressure of the lift cylinder 16, it is possible to determine whether or not the wheel loader 10 is in a scraping operation state.

[0185] (17) In the wheel loader 10 (an example of a working machine) according to this embodiment, the controller determines that it is in an excavation operation state when the bottom pressure of the lift cylinder 16 (an example of a boom cylinder) is equal to or greater than a first threshold value and the height of the working machine 3 is equal to or less than a second threshold value. When the height of the working machine 3 is greater than a third threshold value during the determination of the excavation operation state, it is determined that it is in a scraping operation state. The second threshold value and the third threshold value are set such that the height of the working machine 3 at the third threshold value is higher than the height of the working machine 3 at the second threshold value.

[0186] In this way, by detecting the height of the working machine 3 and the bottom pressure of the lift cylinder 16, it is possible to determine whether or not the wheel loader 10 is in an excavation operation state. After it is determined that it is in an excavation operation state, based on the height of the working machine 3, it is possible to determine whether or not the excavation operation is a scraping operation. This is because the height of the working machine 3 is positioned upward during scraping compared to normal excavation, so in the excavation operation state, it is possible to distinguish between the scraping operation state and states other than the scraping operation.

[0187] (18) The wheel loader 10 (an example of a work machine) according to the present embodiment includes a boom angle sensor 73 that detects the angle of the boom 14. The second threshold value and the third threshold value are set as the angle of the boom 14.

[0188] In this way, by detecting the angle of the boom 14 and the bottom pressure of the lift cylinder 16, it is determined whether the wheel loader 10 is in an excavation work state. After it is determined that the wheel loader 10 is in the excavation work state, based on the angle of the boom 14, it can be determined whether the excavation work is a scraping-up work. This is because when scraping up compared with normal excavation, the boom 14 rotates upward, so in the excavation work state, it is possible to distinguish between the scraping-up work state and the state other than the scraping-up work.

[0189] (19) In the wheel loader 10 (an example of a work machine) according to the present embodiment, the controller 226 (an example of a control unit) determines whether it is in an excavation work state when moving forward. The controller 226 detects the forward movement by the fact that the front tire 4 (an example of a wheel) or the rear tire 7 (an example of a wheel) is rotating forward or the FNR lever 52 (an example of an operation member) that can set the forward or backward movement of the vehicle body 1 is set to the forward position.

[0190] Thereby, the forward movement of the vehicle body 1 can be detected.

[0191] (20) The wheel loader 10 (an example of a work machine) according to the present embodiment further includes an alarm device 61 (an example of a first notification unit). The alarm device 61 notifies that an obstacle (an example of an object) has been detected behind the vehicle body 1 by the rear detection unit 71. The control for suppressing the approach to the rear obstacle S (an example of an object) during backward movement includes stopping the notification by the alarm device 61.

[0192] This makes it possible to prevent the ground G from being erroneously detected as an obstacle and issuing an alarm.

[0193] (21) The control method of the wheel loader 10 (an example of a working machine) according to the present embodiment includes steps S220, S230 (an example of a scraping determination step), steps S250, S280 (an example of a rear detection step), and steps S260, S290 (an example of a control step). S220 and S230 determine the scraping operation state based on the operation of the working machine 3 when the vehicle body 1 having the traveling body and the working machine 3 moves forward by driving the traveling body. Steps S250 and S280 detect an obstacle (an example of an object) behind the vehicle body 1. Steps S260 and S290 change the control for suppressing the approach to the obstacle S (an example of an object) behind during backward movement based on the determination of the scraping operation state.

[0194] This makes it possible to prevent the ground G from being detected as an obstacle when the vehicle body 1 is disposed at a place inclined during the scraping operation, so that false detection of an obstacle can be prevented.

[0195] <Other Embodiments> As described above, an embodiment of the present invention has been described. However, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the invention.

[0196] (A) In the above embodiment, the function of the automatic brake is stopped as shown in the second control of step S13, but it is not limited to being stopped. The opening degree of the brake valve 41 may be set smaller than that in the first control so that a braking force weaker than that in the case of the automatic brake is operated. This weak brake corresponds to an example of suppression of the automatic brake. At this time, the suppression of the automatic brake may be notified by the function OFF notification lamp 62.

[0197] Note that the weak braking force may be generated by controlling when the operator turns off the accelerator 51 instead of adjusting the opening degree of the brake valve 41. When the operator turns off the accelerator 51, the fuel supply to the engine 31 is stopped, and the swash plates of the pump 32a and the motor 32b are controlled to become a resistance to running, and the weak braking force is activated. That is, the brake instruction unit 82 may stop the fuel supply to the engine 31 and control the swash plates of the pump 32a and the motor 32b to become a resistance to running.

[0198] In addition to the control when the accelerator is turned off, the weak braking force may be activated by controlling when the FNR lever 52 is operated to be in the neutral position. When the FNR lever 52 is in the neutral position, the controller 26 controls the solenoids 32d and 32e, and the swash plates of the pump 32a and the motor 32b move to become a resistance to running. That is, the brake instruction unit 82 may stop the fuel supply to the engine 31 and control the swash plates of the pump 32a and the motor 32b to become a resistance to running.

[0199] As a result, the braking force acts and a weak braking force is generated. Note that a larger braking force can be obtained in the neutral position than when only turning off the accelerator 51.

[0200] (B) In the above embodiment, the HST 32 is used in the drive system 21, but it is not limited to the HST, and a torque converter may be used. FIG. 15 is a block diagram showing a configuration in which a torque converter 132 and a transmission 133 are provided in the drive system 21. The driving force from the engine 31 is transmitted to the transmission 133 via the torque converter 132. The transmission 133 shifts the rotational driving force of the engine 31 transmitted via the torque converter 132 and transmits it to the axle 34. The transmission 133 is provided with a parking brake 43.

[0201] In the case of a torque converter, in order to generate the weak braking force described in (A) above, the opening degree of the brake valve 41 may be set small in the same manner as above. Also, although the braking force becomes weaker compared to the HST, it may be sufficient to simply perform control to turn off the accelerator 51. When generating the set braking force, the opening degree of the brake valve 41 may be increased or the parking brake 43 may be used, as in the above-described embodiment.

[0202] Furthermore, not limited to the HST, an HMT (Hydro Mechanical Transmission) may be used.

[0203] (C) In the above-described embodiment, in the second control, the automatic brake is not activated and the warning device 61 is also not activated. However, for example, only the warning device 61 may be activated. Also, only the automatic brake may be activated, or both the automatic brake and the warning device 61 may be activated. When both are activated, in the second control, the braking force of the automatic brake is suppressed and the magnitude of the warning of the warning device 61 is suppressed, etc., so as to be different from the first control.

[0204] (D) The wheel loader 10 of the above-described embodiment has a function of an automatic brake, but it does not necessarily have to have a function of an automatic brake. In this case, in the first control, the automatic brake is not activated and the warning device 61 is activated. Also, in the second control, the warning device 61 is not activated.

[0205] (E) In the above-described embodiment, as an example of the change in the notification of the warning device 61, in the second control, the warning by the warning device 61 is stopped, but not limited to this, the volume of the warning may be suppressed or the output form of the warning may be changed. Changing the output form of the warning means, for example, changing the notification by sound to notification by light.

[0206] (F) Note that for the control of the braking force, the service brake 42, the parking brake 43, and other means for changing the braking force can be appropriately applied.

[0207] (G) In the above-described Embodiment 3, when it is determined in step S210 that the scraping operation state W3 is present, after detecting an obstacle in step S214, the second control is performed in step S215. However, the detection of an obstacle in step S214 may not be provided. When the second control is to perform braking of the automatic brake or weaken the magnitude of the warning, detection of an obstacle is necessary. However, when only the function of the automatic brake and the warning are stopped and the function OFF notification lamp 62 is lit, it can be executed after the determination of the scraping operation state regardless of the presence or absence of obstacle detection.

[0208] (H) In the above-described Embodiment 1, after detecting an obstacle in step S10, it is determined in step S11 whether the inclination angle is equal to or greater than a predetermined threshold value. However, step S11 may be performed before step S10.

[0209] (I) The wheel loader according to the above-described embodiment may be operated by an operator boarding it, or may be operated unmanned.

[0210] (J) In the above-described embodiment, a wheel loader has been described as an example of a work machine, but the present invention is not limited thereto, and a forklift or the like may be used.

Industrial Applicability

[0211] According to the work machine and the control method of the work machine of the present disclosure, it is possible to achieve an effect of reducing warnings due to false detection, and it is useful as a bulldozer, a wheel loader, or the like.

Explanation of Signs

[0212] 1: Vehicle body 10: Wheel loader 26: Controller 71: Rear detection unit 72: Vehicle body angle sensor< / url:>

Claims

1. A vehicle body having a traveling body and a working machine disposed in front of the traveling body; A rear detection unit that detects an object behind the vehicle body; A control unit that determines whether or not it is in a scraping operation state based on the operation of the working machine when the traveling body is moving forward by driving, and when it is determined that it is in the scraping operation state, changes the control to suppress the approach to the object when an object is detected by the rear detection unit during reverse travel; The working machine includes: A boom swingably attached to the front portion of the traveling body; A bucket connected to the boom so that an opening is disposed forward and driven with respect to the boom; A boom cylinder that drives the boom; A boom bottom pressure sensor that detects the bottom pressure of the boom cylinder; A working machine height detection unit that detects the height of the working machine; The control unit determines whether or not it is in the scraping operation state based on the bottom pressure of the boom cylinder and the height of the working machine; The control for suppressing the approach to the object is an automatic brake that automatically brakes the vehicle body; The change of the control is the stop of the automatic brake or the suppression of the braking force of the automatic brake; Work machine.

2. The control unit: Determines that it is in an excavation operation state when the bottom pressure of the boom cylinder is equal to or greater than a first threshold value and the height of the working machine is equal to or less than a second threshold value, and determines that it is in the scraping operation state when the height of the working machine is greater than a third threshold value during the determination of the excavation operation state; The second threshold value and the third threshold value are set so that the height of the working machine at the third threshold value is higher than the height of the working machine at the second threshold value; The work machine according to claim 1.

3. The working machine height detection unit: Has a boom angle sensor that detects the angle of the boom; The second threshold value and the third threshold value are set as the angle of the boom; The work machine according to claim 2.

4. The control unit determines whether or not it is in the excavation operation state when moving forward; The control unit detects that it is moving forward when the wheels of the vehicle body are rotating forward or when an operation member capable of setting the forward or reverse travel of the vehicle body is set to the forward position; The work machine according to claim 2.

5. The vehicle body further includes a first notification unit that notifies that an object has been detected behind the vehicle body by the rear detection unit. The control for suppressing the approach to an object behind during reverse travel includes a change in the notification by the first notification unit. The work machine according to claim 1.

6. A scraping determination step of determining a scraping work state based on the operation of the work machine when the traveling body of the vehicle body having the traveling body and the work machine travels forward by driving the traveling body, A rear detection step of detecting an object behind the vehicle body, And a control step of changing the control for suppressing the approach to the object when the object is detected by the rear detection step during reverse travel when it is determined that the scraping work state is present. The work machine is A boom swingably attached to the front part of the traveling body, A bucket connected to the boom so that an opening faces forward and driven with respect to the boom, And a boom cylinder for driving the boom. A boom bottom pressure detection step of detecting the bottom pressure of the boom cylinder, And a work machine height detection step of detecting the height of the work machine. The control step determines whether or not the scraping work state is present based on the bottom pressure of the boom cylinder and the height of the work machine. The control for suppressing the approach to the object is an automatic brake for automatically braking the vehicle body. The change in the control is the stop of the automatic brake or the suppression of the braking force of the automatic brake. A control method for a work machine.

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