Work machine, system including work machine, and control method for notification device

Abstract

The present application provides a kind of work machine capable of inhibiting the piston of hydraulic cylinder to reach the end of stroke.The work machine is provided with a vehicle body, a working device supported by the vehicle body, a hydraulic cylinder driving the working device, a notification device notifying an alarm, and a controller controlling the hydraulic cylinder and the notification device.The hydraulic cylinder has a cylinder portion and a piston capable of reciprocating within the cylinder portion.The controller causes the notification device to notify the alarm when the piston reaches an alarm notification position ahead of the end of stroke of the hydraulic cylinder, and can adjust the timing of alarm notification.

Description

Technical Field

[0001] The present disclosure relates to a work machine, a system including the work machine, and a control method of a notification device. Background Art

[0002] Japanese Patent Application Laid-Open No. 11-158930 (Patent Document 1) proposes the following device. A front device is installed at the front of the rotary body of a hydraulic excavator. The front device consists of a boom, an arm, and a bucket, each of which can rotate vertically. The boom, arm, and bucket are driven by boom cylinders, arm cylinders, and bucket cylinders, respectively. When a cylinder approaches the end of its stroke, an alarm sounds to notify the operator.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 11-158930 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] Even if an inexperienced operator recognizes an alarm indicating that the hydraulic cylinder's piston is nearing the end of its stroke, it is difficult for them to operate the hydraulic cylinder so that the piston does not reach the end of its stroke. The piston physically hits the end of its stroke, causing noise.

[0008] The present disclosure proposes a working machine capable of suppressing a piston of a hydraulic cylinder from reaching a stroke end, a system including the working machine, and a control method for a notification device.

[0009] Means for solving problems

[0010] According to the present disclosure, a work machine is provided, comprising a vehicle body, a working device supported by the vehicle body, a hydraulic cylinder driving the working device, a notification device for issuing an alarm, and a controller controlling the hydraulic cylinder and the notification device. The hydraulic cylinder comprises a cylinder portion and a piston capable of reciprocating within the cylinder portion. The controller causes the notification device to issue an alarm when the piston reaches an alarm notification position closer to the end of the hydraulic cylinder's stroke, and the timing of the alarm notification can be adjusted.

[0011] Effects of the Invention

[0012] According to the present disclosure, it is possible to suppress the piston of the hydraulic cylinder from reaching the end of the stroke, thereby reducing noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a side view schematically showing the structure of the working machine according to the embodiment.

[0014] Figure 2 It shows Figure 1 Block diagram of the hydraulic circuit and operating device of the working machine shown.

[0015] Figure 3 It shows Figure 2 Diagram showing the functional blocks within the controller.

[0016] Figure 4 This is a flowchart showing the flow of preliminary preparation processing for controlling a work machine.

[0017] Figure 5 This is a flowchart showing the flow of a process for adjusting an alarm notification position based on the operator's proficiency.

[0018] Figure 6 This is a diagram showing an example of the operation performed when a skilled operator is notified of an alarm.

[0019] Figure 7 This is a diagram showing an example of the operation performed by an inexperienced operator when an alarm is notified.

[0020] Figure 8 Is shown adjusted Figure 5 Flowchart showing the flow of processing of the subroutine of the alarm notification position.

[0021] Figure 9 1 is a flowchart showing the flow of a process for adjusting the alarm notification position based on the cylinder speed.

[0022] Figure 10 This is a diagram showing an example of the operation when the cylinder speed is high.

[0023] Figure 11 This is a diagram showing an example of the operation when the cylinder speed is low.

[0024] Figure 12 This is a diagram showing an example of an alarm notification position and a stroke limit position.

[0025] Figure 13 This is a flowchart showing the flow of processing for canceling the stroke limit control according to the intention of the operator during operation.

[0026] Figure 14 This is a flowchart showing the flow of processing for canceling the stroke restriction control based on a setting made in advance by the operator.

[0027] Figure 15 This is a schematic diagram of a system including a work machine. DETAILED DESCRIPTION

[0028] Hereinafter, the embodiment will be described based on the accompanying drawings. In the following description, the same reference numerals are used for the same components. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[0029] In the following description, “up,” “down,” “front,” “rear,” “left,” and “right” refer to directions relative to an operator sitting on the driver's seat 2b in the cab 2a.

[0030] <Structure of operating machinery>

[0031] Figure 1 1 is a side view schematically showing the structure of a hydraulic excavator 100 as an example of a working machine according to the embodiment. Figure 1 As shown, the hydraulic excavator 100 of this embodiment mainly includes a traveling structure 1, a revolving structure 2, and a working device 3. The traveling structure 1 and the revolving structure 2 constitute a vehicle body of the hydraulic excavator 100.

[0032] The traveling body 1 includes a pair of left and right crawler track devices 1a. Each of the left and right crawler track devices 1a includes crawler tracks. The hydraulic excavator 100 self-propels by rotating the left and right crawler tracks. The traveling body 1 may also include wheels (tires) instead of the crawler track devices 1a.

[0033] The revolving structure 2 is arranged to be freely rotatable relative to the traveling structure 1. The revolving structure 2 primarily comprises a cab 2a, a driver's seat 2b, an engine compartment 2c, and a counterweight 2d. The cab 2a is located, for example, on the front left side (the front side of the vehicle) of the revolving structure 2. A driver's seat 2b is located within the interior of the cab 2a, where the operator sits. In the present disclosure, the hydraulic excavator 100 is operated from within the cab 2a. However, the hydraulic excavator 100 can also be operated wirelessly remotely from a location remote from the hydraulic excavator 100.

[0034] The engine compartment 2c and counterweight 2d are located behind the revolving structure 2 (on the vehicle's rear side) relative to the cab 2a. The engine compartment 2c houses the engine unit (engine, exhaust treatment structure, etc.). The top of the engine compartment 2c is covered by an engine hood. The counterweight 2d is located behind the engine compartment 2c.

[0035] The work implement 3 is supported by the revolving structure 2 at the front portion thereof, for example, on the right side of the cab 2a. The work implement 3 includes, for example, a boom 3a, an arm 3b, a bucket 3c, a boom cylinder 4a, an arm cylinder 4b, and a bucket cylinder 4c.

[0036] The base end of the boom 3a is rotatably connected to the revolving structure 2 via a boom mount pin 5a. The base end of the arm 3b is rotatably connected to the front end of the boom 3a via an arm connecting pin 5b. The bucket 3c is rotatably connected to the front end of the arm 3b via a bucket connecting pin 5c. The bucket 3c has multiple teeth. The front end of the bucket 3c is referred to as the blade tip 3ce. It should be noted that the bucket 3c does not necessarily have teeth. The front end of the bucket 3c can also be formed of a straight steel plate.

[0037] The boom 3a can be driven by the boom cylinder 4a. This drive allows the boom 3a to rotate relative to the revolving structure 2 about the boom mount pin 5a. The arm 3b can be driven by the arm cylinder 4b. This drive allows the arm 3b to rotate relative to the boom 3a about the arm connecting pin 5b. The bucket 3c can be driven by the bucket cylinder 4c. This drive allows the bucket 3c to rotate relative to the arm 3b about the bucket connecting pin 5c.

[0038] The bucket 3c is an example of an attachment that is detachably mounted on the front end of the work machine 3 and is rotatable relative to the arm 3b. Depending on the type of work, the attachment can be replaced with a breaker, a grab bucket, or a lifting magnet.

[0039] The work implement 3 includes a bucket link 3d. The bucket link 3d includes a first link member 3da and a second link member 3db. The first link member 3da and the second link member 3db are connected so as to be rotatable relative to each other. The first link member 3da and the second link member 3db are pin-connected to the bucket cylinder 4c. The first link member 3da is rotatably connected to the arm 3b. The second link member 3db is rotatably connected to a bracket at the base of the bucket 3c.

[0040] The boom cylinder 4a, arm cylinder 4b, and bucket cylinder 4c are hydraulic cylinders driven by hydraulic oil. The boom 3a, arm 3b, and bucket 3c are driven by the hydraulic cylinders, thereby enabling the operation of the work machine 3. The hydraulic cylinders can drive the work machine 3.

[0041] The boom unloader 4a has a cylinder portion 4aa, a rod 4ab, and a piston 4ac. The cylinder portion 4aa has a cylindrical shape. The cylinder portion 4aa is rotatably connected to the rotary body 2 at one end extending along its cylindrical shape. The piston 4ac is housed in a cylinder chamber inside the cylinder portion 4aa and is capable of reciprocating in the cylinder chamber along the length direction (axial direction) of the cylinder portion 4aa. The piston 4ac is capable of reciprocating inside the cylinder portion 4aa, between the ends of each stroke in the extension and contraction directions of the boom cylinder 4a, i.e., the stroke ends. The rod 4ab extends along the length direction of the cylinder portion 4aa. The base end of the rod 4ab is fixed to the piston 4ac. The front end of the rod 4ab is rotatably connected to the boom 3a.

[0042] The arm cylinder 4b has the same structure as the boom cylinder 4a, and includes a cylinder portion 4ba, a rod 4bb, and a piston 4bc (in Figure 1 Not shown in the figure, refer to Figure 2 The piston 4bc can reciprocate inside the cylinder portion 4ba between the end points of the strokes in the extension and contraction directions of the arm cylinder 4b. The bucket cylinder 4c has the same structure as the boom cylinder 4a, and includes a cylinder portion 4ca, a rod 4cb, and a piston 4cc (in the Figure 1 Not shown in the figure, refer to Figure 2 The piston 4cc is capable of reciprocating within the cylinder portion 4ca between the stroke ends, which are the respective ends of the stroke in the extension and contraction directions of the bucket cylinder 4c.

[0043] A stroke sensor 7a is mounted on the boom cylinder 4a. The stroke sensor 7a detects the displacement of the piston 4ac in the boom cylinder 4a relative to the cylinder portion 4aa. A stroke sensor 7b is mounted on the arm cylinder 4b. The stroke sensor 7b detects the displacement of the piston 4bc in the arm cylinder 4b relative to the cylinder portion 4ba. A stroke sensor 7c is mounted on the bucket cylinder 4c. The stroke sensor 7c detects the displacement of the piston 4cc in the bucket cylinder 4c relative to the cylinder portion 4ca.

[0044] An angle sensor 9a is mounted around the boom mount pin 5a. An angle sensor 9b is mounted around the arm coupling pin 5b. An angle sensor 9c is mounted around the bucket coupling pin 5c. Angle sensors 9a, 9b, and 9c may be potentiometers or rotary encoders.

[0045] like Figure 1 As shown, in side view, the straight line ( Figure 1 The double-dashed line in the figure) and the straight line extending in the up-down direction ( Figure 1The angle formed by the boom 3a and the swing body 2 (shown by a dotted line in FIG) is defined as the boom angle θb. The boom angle θb represents the angle of the boom 3a relative to the swing body 2. The boom angle θb can be calculated based on the detection result of the stroke sensor 7a or the measurement value of the angle sensor 9a.

[0046] In a side view, the straight line passing through the boom mount pin 5a and the arm connecting pin 5b and the straight line passing through the arm connecting pin 5b and the bucket connecting pin 5c ( Figure 1 The angle formed by the arm 3b and the boom 3a (shown by a two-dot chain line in the figure) is defined as the arm angle θa. The arm angle θa represents the angle of the arm 3b relative to the boom 3a. The arm angle θa can be calculated based on the detection results of the stroke sensor 7b or the measurement value of the angle sensor 9b.

[0047] In a side view, a straight line passing through the arm connecting pin 5b and the bucket connecting pin 5c and a straight line passing through the bucket connecting pin 5c and the blade edge 3ce ( Figure 1 The angle formed by the bucket 3c and the arm 3b (shown by a two-dot chain line in FIG. 3 ) is referred to as the bucket angle θk. The bucket angle θk represents the angle of the bucket 3c relative to the arm 3b. The bucket angle θk can be calculated based on the detection results of the stroke sensor 7c or the measurement value of the angle sensor 9c.

[0048] <Hydraulic circuits and operating devices for operating machinery>

[0049] Next, use Figure 2 Explain the hydraulic circuits and operating devices of work machines. Figure 2 It shows Figure 1 Block diagram of the hydraulic circuit and operating device of the working machine shown.

[0050] The engine 42 is, for example, a diesel engine. The output of the engine 42 is controlled by controlling the amount of fuel injected into the engine 42. A hydraulic pump 43 is connected to the engine 42. The rotational driving force of the engine 42 is transmitted to the hydraulic pump 43, thereby driving the hydraulic pump 43. For example, the hydraulic pump 43 may be a variable displacement hydraulic pump having a swash plate and varying the discharge capacity by changing the tilting angle of the swash plate.

[0051] A portion of the oil discharged from the hydraulic pump 43 is supplied as hydraulic oil to the main valve 41. The remaining oil discharged from the hydraulic pump 43 is reduced in pressure to a predetermined level by a self-operated pressure-reducing valve 45 and supplied as a pilot. The oil reduced in pressure by the self-operated pressure-reducing valve 45 is supplied to the main valve 41 via an EPC (Electromagnetic Proportional Control) valve 46.

[0052] The EPC valve 46 receives a current command from the controller 20. The EPC valve 46 generates a pilot pressure corresponding to a current value of the current command. The EPC valve 46 drives the spool of the main valve 41 by the pilot pressure.

[0053] The main valve 41 is connected to the boom cylinder 4a, arm cylinder 4b, bucket cylinder 4c, and swing motor 44, which serve as hydraulic actuators. The swing motor 44 rotates the swing structure 2 relative to the travel structure 1. The spool of the main valve 41 moves axially to adjust the amount of hydraulic oil supplied to each hydraulic actuator. This controls the movement of the work implement 3 and the rotation of the swing structure 2.

[0054] In this example, the oil supplied to the hydraulic actuator to operate it is called hydraulic oil. The oil supplied to the pressure-receiving chamber of main valve 41 to drive the spool in order to operate main valve 41 is called pilot oil. The pressure of the pilot oil is called PPC pressure (pilot pressure).

[0055] The hydraulic pump 43 may be a pump that delivers both hydraulic oil and pilot oil as described above. The hydraulic pump 43 may also be separately provided with a hydraulic pump that delivers hydraulic oil (main hydraulic pump) and a hydraulic pump that delivers pilot oil (pilot hydraulic pump).

[0056] The EPC valve 46 is controlled by a command from the controller 20 based on an operation command from the operating device 25. Operation of the operating device 25 causes various operations such as excavation, rotation of the revolving structure 2 relative to the traveling structure 1, and discharge of a load from the bucket 3c.

[0057] The operating device 25 is arranged in the cab 2a ( Figure 1 ) inside. The operating device 25 is operated by an operator. The operating device 25 receives operator operation to drive the working device 3. The operating device 25 receives operator operation to rotate the rotating body 2. The operating device 25 is operated by an operator to drive the hydraulic cylinder.

[0058] The operating device 25 includes a first operating lever 25L and a second operating lever 25R. The first operating lever 25L is disposed on the driver's seat 2b ( Figure 1 ) on the left side. The second operating lever 25R is disposed, for example, on the right side of the driver's seat 2b. For the first operating lever 25L and the second operating lever 25R, the front, rear, left, and right movements correspond to the movements of the two axes.

[0059] The first operating lever 25L is used to operate, for example, the arm 3b and the revolving unit 2. Forward-backward operation of the first operating lever 25L corresponds to, for example, rotation of the revolving unit 2, and corresponding forward-backward operation causes the revolving unit 2 to rotate right and left. Forward-backward operation of the first operating lever 25L corresponds to, for example, operation of the arm 3b, and corresponding left-right operation causes the arm 3b to move in the unloading direction (upward) and the excavation direction (downward).

[0060] The second operating lever 25R is used to operate, for example, the boom 3a and bucket 3c. Forward and backward movement of the second operating lever 25R corresponds to, for example, movement of the boom 3a, and the boom 3a is lowered or raised in response to the forward and backward movement. Forward and backward movement of the second operating lever 25R corresponds to, for example, movement of the bucket 3c, and the bucket 3c is moved in the digging direction (upward) or the unloading direction (downward) in response to the forward and backward movement.

[0061] It should be noted that the front-to-back operation of the first operating lever 25L may correspond to the operation of the arm 3b, and the left-to-right operation may correspond to the operation of the revolving structure 2. Alternatively, the left-to-right operation of the second operating lever 25R may correspond to the operation of the boom 3a, and the front-to-back operation may correspond to the operation of the bucket 3c.

[0062] The operating device 25 outputs an operation signal corresponding to the operator's operation. Based on the operation signal output from the operating device 25, the operation amount of the operating device 25 is detected by the operation amount sensor 26. The operation amount sensor 26 is, for example, a potentiometer or a Hall effect element. The signal of the operation amount detected by the operation amount sensor 26 is input to the controller 20. As described above, the controller 20 controls the EPC valve 46 based on the operation command from the operating device 25.

[0063] In this example, the operating device 25 is, for example, an electric operating device, but may also be a pilot hydraulic operating device. In the case of a pilot hydraulic operating device, the amount of operation of the operating device 25 is detected by, for example, a pressure sensor that detects oil pressure.

[0064] The controller 20 is, for example, a computer, a server, a mobile terminal, etc., and includes a CPU (Central Processing Unit), a memory, a timer, etc. The controller 20 may be mounted on the hydraulic excavator 100 or installed at a remote location away from the hydraulic excavator 100 .

[0065] <Functional Blocks in Controller 20>

[0066] Next, use Figure 3 right Figure 2Functional blocks within the controller 20 are described below. Figure 3 It shows Figure 2 FIG. 2 is a diagram of the functional blocks within the controller 20. Figure 3 As shown, the controller 20 includes a cylinder stroke calculation unit 21 , an alarm notification unit 22 , a stroke limit control unit 23 , and a stroke limit control release unit 24 .

[0067] The cylinder stroke calculation unit 21 includes a boom calculation unit 21 a , an arm calculation unit 21 b , and a bucket calculation unit 21 c .

[0068] The boom calculation unit 21a calculates the length of the range of movement of the piston 4ac in the longitudinal direction of the cylinder portion 4aa of the boom cylinder 4a (e.g., the distance between the end of the stroke on the extension side and the end of the stroke on the retraction side, hereinafter referred to as the maximum stroke of the boom cylinder 4a) based on the detection results of the stroke sensor 7a installed on the boom cylinder 4a. The boom calculation unit 21a determines the current position of the piston 4ac in the longitudinal direction of the cylinder portion 4aa of the boom cylinder 4a based on the detection results of the stroke sensor 7a or based on the corresponding relationship with the boom angle θb measured by the angle sensor 9a.

[0069] The boom calculation unit 21b calculates the length of the range within which the piston 4bc can move in the longitudinal direction of the cylinder portion 4ba of the boom cylinder 4b (e.g., the distance between the end of the stroke on the extension side and the end of the stroke on the contraction side. Hereinafter, this is referred to as the maximum stroke of the boom cylinder 4b) based on the detection results of the stroke sensor 7b mounted on the boom cylinder 4b. The boom calculation unit 21b determines the current position of the piston 4bc in the longitudinal direction of the cylinder portion 4ba of the boom cylinder 4b based on the detection results of the stroke sensor 7b or based on the correspondence with the boom angle θa measured by the angle sensor 9b.

[0070] The bucket calculation unit 21c calculates the length of the range of movement of the piston 4cc in the longitudinal direction of the cylinder portion 4ca of the bucket cylinder 4c (e.g., the distance between the end of the stroke on the extension side and the end of the stroke on the contraction side, hereinafter referred to as the maximum stroke of the bucket cylinder 4c) based on the detection results of the stroke sensor 7c attached to the bucket cylinder 4c. The bucket calculation unit 21c determines the current position of the piston 4cc in the longitudinal direction of the cylinder portion 4ca of the bucket cylinder 4c based on the detection results of the stroke sensor 7c or based on the corresponding relationship with the bucket angle θk measured by the angle sensor 9c.

[0071] The alarm notification unit 22 includes a boom notification unit 22a, an arm notification unit 22b, and a bucket notification unit 22c.

[0072] When the piston 4ac of the boom cylinder 4a reaches the alarm notification position, the boom notification unit 22a sends a control signal to the notification device 60, causing the notification device 60 to issue an alarm. When the piston 4bc of the arm cylinder 4b reaches the alarm notification position, the arm notification unit 22b sends a control signal to the notification device 60, causing the notification device 60 to issue an alarm. When the piston 4cc of the bucket cylinder 4c reaches the alarm notification position, the bucket notification unit 22c sends a control signal to the notification device 60, causing the notification device 60 to issue an alarm.

[0073] The notification device 60 includes a lamp 61, a buzzer 62, a vibrator 63, etc. The notification device 60 receives a control signal from the alarm notification unit 22 and notifies the operator of an alarm. The vibrator 63 may be provided on the first operating lever 25L and the second operating lever 25R, for example.

[0074] The stroke limit control unit 23 includes a boom limiter 23 a , an arm limiter 23 b , and a bucket limiter 23 c .

[0075] The boom limiter 23a controls the piston 4ac of the boom cylinder 4a so that it does not reach the end of its stroke. The arm limiter 23b controls the piston 4bc of the arm cylinder 4b so that it does not reach the end of its stroke. The bucket limiter 23c controls the piston 4cc of the bucket cylinder 4c so that it does not reach the end of its stroke. Hereinafter, the control that prevents each piston 4ac, 4bc, and 4cc from reaching the end of their stroke will be referred to as stroke limiter control.

[0076] The stroke limit control release unit 24 includes a boom release unit 24 a , an arm release unit 24 b , and a bucket release unit 24 c .

[0077] The boom release unit 24a releases the stroke limit control by the boom limiter 23a, allowing the piston 4ac of the boom cylinder 4a to reach the stroke end. The arm release unit 24b releases the stroke limit control by the arm limiter 23b, allowing the piston 4bc of the arm cylinder 4b to reach the stroke end. The bucket release unit 24c releases the stroke limit control by the bucket limiter 23c, allowing the piston 4cc of the bucket cylinder 4c to reach the stroke end.

[0078] The stroke limit control unit 23 and the stroke limit control release unit 24 stop the spool of the main valve 41 or allow the driving of the spool of the main valve 41 by appropriately sending a control signal to the EPC valve 46 .

[0079] The operating unit 30 is operated by the operator. The operating unit 30 can be located within the cab 2a. Alternatively, the operating unit 30 can be located in a position where it can be easily operated by the operator seated in the driver's seat 2b. The operating unit 30 includes a monitor 31, switches 32, and the like. The monitor 31 can be a touch panel. The switches 32 can be any type of switch, such as a push button. For example, the switches 32 can be located on the first operating lever 25L and the second operating lever 25R.

[0080] The operator enables or disables the stroke limit control by operating the operation unit 30. The operation contents of the operation unit 30 performed by the operator are input to the stroke limit control setting unit 50. The stroke limit control setting unit 50 inputs the setting of whether to execute or not execute the stroke limit control into the controller 20.

[0081] The monitor 31 may also function as the notification device 60. The operator may be notified of an alarm through a display on the monitor 31.

[0082] <Control Method of Working Machine>

[0083] The following describes control for suppressing the pistons 4ac, 4bc, and 4cc of the hydraulic cylinders from reaching the stroke ends in the working machine (hydraulic excavator 100) having the above configuration.

[0084] Figure 4 Flowchart 1 is a flowchart showing the flow of preliminary preparation processing for controlling the working machine. Figure 4 As shown, first, in step S1, the controller 20 obtains the maximum stroke of the hydraulic cylinder. Figure 3 As described above, the boom calculation unit 21a calculates the maximum stroke of the boom cylinder 4a based on the detection results of the stroke sensor 7a attached to the boom cylinder 4a. The arm calculation unit 21b calculates the maximum stroke of the arm cylinder 4b based on the detection results of the stroke sensor 7b attached to the arm cylinder 4b. The bucket calculation unit 21c calculates the maximum stroke of the bucket cylinder 4c based on the detection results of the stroke sensor 7c attached to the bucket cylinder 4c.

[0085] In step S2, the controller 20 sets the alarm notification position. The boom notification unit 22b sets the alarm notification position at a position closer to the end of the stroke, referring to the maximum stroke of the boom cylinder 4b determined in step S1. The boom notification unit 22b sets the alarm notification position as follows: when the operator stops operating the boom 3b after an alarm is recognized, the piston 4bc does not reach the end of the stroke, but the stationary position of the piston 4bc is as close to the end of the stroke as possible. The boom notification unit 22a and the bucket notification unit 22c also set the alarm notification position in the same manner.

[0086] In step S3, the controller 20, specifically the stroke limit control unit 23, sets the stroke limit position. The stroke limit position is set to a position where the piston begins to decelerate due to intervention by the controller 20, which stops the piston before reaching the stroke end. The stroke limit position is set between the alarm notification position and the stroke end. When the piston, moving toward the stroke end, reaches the stroke limit position, the piston begins to decelerate. This is how preliminary processing is performed.

[0087] (Adjustment of the alarm notification position based on the operator's proficiency)

[0088] The controller 20 of the embodiment is configured to be able to adjust the alarm notification position based on the operator's proficiency and change the timing of notifying the operator of the alarm. Figure 5 This is a flowchart showing the flow of a process for adjusting an alarm notification position based on the operator's proficiency.

[0089] like Figure 5 As shown, in step S11, the controller 20 receives input from the operator regarding operation of the operating levers. When the operator operates the first operating lever 25L and / or the second operating lever 25R, the operation amount sensor 26 detects the operation direction and amount of the levers. Signals indicating the operation direction and amount of the levers detected by the operation amount sensor 26 are input to the controller 20. In step S12, the controller 20 initiates operation of the work implement 3 in response to the operator's operation.

[0090] In step S13, the controller 20 obtains the current position of the piston. The boom calculation unit 21a calculates the current position of the piston 4ac based on the detection results of the stroke sensor 7a or the angle sensor 9a. The arm calculation unit 21b calculates the current position of the piston 4bc based on the detection results of the stroke sensor 7b or the angle sensor 9b. The bucket calculation unit 21c calculates the current position of the piston 4cc based on the detection results of the stroke sensor 7c or the angle sensor 9c.

[0091] In step S14, the controller 20 determines whether the piston has reached the alarm notification position. The boom notification unit 22a determines whether piston 4ac has reached the specified alarm notification position based on the current position of piston 4ac of the boom cylinder 4a calculated by the boom calculation unit 21a. The arm notification unit 22b determines whether piston 4bc has reached the specified alarm notification position based on the current position of piston 4bc of the arm cylinder 4b calculated by the arm calculation unit 21b. The bucket notification unit 22c determines whether piston 4cc has reached the specified alarm notification position based on the current position of piston 4cc of the bucket cylinder 4c calculated by the bucket calculation unit 21c.

[0092] If it is determined that the piston has reached the alarm notification position (No in step S14 ), the acquisition of the current position of the piston in step S13 and the determination in step S14 are repeated.

[0093] If it is determined that the piston has reached the alarm notification position (YES in step S14), the process proceeds to step S15, where an alarm is notified to the operator. The alarm notification unit 22 outputs a control signal to the notification device 60. Upon receiving the control signal, the notification device 60 illuminates the lamp 61, emits a sound from the buzzer 62, or vibrates the vibrator 63, thereby notifying the operator of the alarm.

[0094] The operator, upon recognizing the alarm, reduces the amount of operation of the first operating lever 25L and / or the second operating lever 25R. Typically, the operator removes their hand from the previously operated first operating lever 25L and / or second operating lever 25R. The amount of operation sensor 26 detects the reduction in the amount of operation of the first operating lever 25L and / or the second operating lever 25R and inputs the reduction in the amount of operation to the controller 20.

[0095] The controller 20, having received input from the operator, reduces the opening of the EPC valve 46, thereby reducing fluctuations in the pilot pressure supplied to the main valve 41. By suppressing the movement of the spool of the main valve 41, the movement speed of the hydraulic cylinder's piston is reduced, thereby slowing the movement speed of the work implement 3. Typically, the controller 20 fully closes the EPC valve 46, thereby stopping the movement of the spool of the main valve 41. By bringing the piston of the hydraulic cylinder to a standstill, the movement of the work implement 3 is stopped (step S16).

[0096] In step S17, the controller 20 obtains the resting position of the piston. The boom calculation unit 21a calculates the resting position of the piston 4ac based on the detection results of the stroke sensor 7a or the angle sensor 9a. The arm calculation unit 21b calculates the resting position of the piston 4bc based on the detection results of the stroke sensor 7b or the angle sensor 9b. The bucket calculation unit 21c calculates the resting position of the piston 4cc based on the detection results of the stroke sensor 7c or the angle sensor 9c.

[0097] In step S18 , the controller 20 adjusts the alarm notification position as needed to change the timing of notifying the alarm.

[0098] Even if the alarm is notified in step S15, if it takes time for the operator who recognizes the alarm to reduce the amount of operation of the operating device, the piston may not be stopped just before the stroke end and reach the stroke end. Figure 6 and the following Figure 7 、 8 Next, a description will be given of a process for adjusting the alarm notification process based on the proficiency of the operator operating the hydraulic excavator 100 .

[0099] Figure 6 : is a diagram showing an example of the operation performed by a skilled operator when an alarm is notified. Figure 6 and the following Figure 7 、 10 In FIG. 12 , the horizontal axis represents time, and the vertical axis represents the cylinder stroke amount, that is, the movement distance of the piston in the hydraulic cylinder toward the stroke end.

[0100] like Figure 6 As shown, when a skilled operator operates hydraulic excavator 100, an alarm is issued at time t11. Recognizing the alarm, the operator begins reducing the amount of operation on operating device 25 at time t12. Time T1 elapses from the time the alarm is issued to the time the amount of operation on operating device 25 begins to decrease. Through the above-described operation, the piston comes to rest at a distance L from the end of the stroke. Distance L can be, for example, 10% of the maximum stroke.

[0101] Figure 7 : is a diagram showing an example of the actions of an inexperienced operator when an alarm is notified. Figure 6 Similarly to the operation of the skilled operator shown, in order to stop the piston at a position of a distance L from the stroke end, it may be necessary to start reducing the operation amount of the operating device 25 at time t12.

[0102] Even if an inexperienced operator recognizes the alarm, he cannot immediately stop the operation of the operating device 25. Therefore, a longer time T2 is required from the time the alarm is notified to the time the amount of operation of the operating device 25 begins to decrease. Figure 6 The alarm is notified at time t21 earlier than time t11 shown. Figure 7 The alarm notification location shown is the same as Figure 6 In comparison, it is set further away from the end of the stroke.

[0103] The operator of the hydraulic excavator 100 can adjust the alarm notification position and determine the timing of the alarm notification based on their own experience as an initial setting before starting operation. If an inexperienced operator is operating the hydraulic excavator 100, advancing the alarm notification timing can prevent the hydraulic cylinder piston from reaching the end of its stroke, thereby reducing noise.

[0104] On the other hand, the controller 20 recognizes the operator's proficiency during work and automatically adjusts the alarm notification position through feedback control based on the operator's proficiency, thereby changing the timing of notifying the operator of the alarm. Figure 8 It shows Figure 51 is a flowchart of the process flow of the subroutine for adjusting the alarm notification position in step S18 shown in FIG.

[0105] In step S21 , the controller 20 determines whether the rest position of the piston acquired in step S17 is the stroke end of the hydraulic cylinder.

[0106] If it is determined that the rest position of the piston is at the end of the stroke (Yes in step S21), the process proceeds to step S22, where the controller 20 increments the number of times the piston reaches the end of the stroke. Figure 5 In the process before the process shown, the number of times the piston's rest position is the stroke end is stored in the memory. The controller 20 reads the number of times the piston reaches the stroke end from the memory and performs a process of adding 1 to the number of times the piston reaches the stroke end.

[0107] In step S23 , the controller 20 compares the increased number of arrivals with a predetermined reference number stored in the memory, and determines whether the number of arrivals is equal to or greater than the reference number.

[0108] If the number of arrivals is greater than the reference number (YES in step S23), the controller 20 determines that despite the alarm indicating that the hydraulic cylinder piston is nearing the stroke end in step S15, repeated operations have been performed to cause the piston to collide with the stroke end. This indicates that the hydraulic excavator 100 is being operated by an inexperienced operator. In this case, the process proceeds to step S24, where adjustments are made to advance the timing of the alarm notification and move the alarm notification position away from the stroke end.

[0109] In the determination of step S23 , if the number of arrivals is less than the reference number (No in step S23 ), the process of adjusting the alarm notification position is not performed, and the process returns.

[0110] In step S21, if it is determined that the piston's stationary position is not the stroke end, but the piston is stationary at a position before the stroke end (No in step S21), the process proceeds to step S25, and the controller 20 calculates the distance between the piston's stationary position and the stroke end.

[0111] In step S26 , the controller compares the distance calculated in step S25 with a predetermined reference distance stored in the memory, and determines whether the distance between the rest position of the piston and the stroke end is greater than or equal to the reference distance.

[0112] If the distance is greater than the reference distance (YES in step S26), and if it is determined that the operator, having recognized the alarm notified in step S15, immediately stopped operating the operating device 25, causing the piston to come to rest at a position away from the stroke end, the controller recognizes that the hydraulic excavator 100 is being operated by a skilled operator. In this case, the process proceeds to step S27, where the timing of the alarm notification is delayed to adjust the position of the alarm notification closer to the stroke end.

[0113] In the determination of step S26 , if the distance is less than the reference distance (No in step S26 ), the process of adjusting the alarm notification position is not performed and the process returns.

[0114] The controller 20 recognizes the proficiency of the operator operating the hydraulic excavator 100 based on the rest position of the piston after the alarm is notified by the notification device 60. The controller 20 adjusts the alarm notification position based on the operator's proficiency.

[0115] When the hydraulic excavator 100 is being operated by an inexperienced operator, the controller 20 changes the timing of the early warning notification, thereby preventing the piston of the hydraulic cylinder from reaching the stroke end and reducing noise.

[0116] When the hydraulic excavator 100 is being operated by a skilled operator, the controller 20 can further shorten the distance from the piston's resting position to the stroke end by changing the timing of the delayed alarm notification. By operating the work implement 3 over a wider range of the hydraulic cylinder's maximum stroke, work efficiency can be improved.

[0117] like Figure 6 、 7 As shown, the time T1 from when an experienced operator recognizes an alarm to when the amount of operation of the operating device 25 starts to decrease is shorter, while the time T2 from when an inexperienced operator recognizes an alarm to when the amount of operation of the operating device 25 starts to decrease is longer. Therefore, the controller 20 can identify the proficiency of the operator based on the time from when the alarm is notified to when the amount of operation of the operating device 25 starts to decrease.

[0118] For example, the controller 20 can compare the time from when the alarm is notified until the amount of operation on the operating device 25 begins to decrease with a predetermined reference time stored in memory. If this time is shorter than the reference time, the controller 20 recognizes that the operation is being performed by an experienced operator and can delay the timing of the alarm notification, moving the alarm notification location closer to the end of the stroke. If this time is longer than the reference time, the controller 20 recognizes that the operation is being performed by an inexperienced operator and can advance the timing of the alarm notification, moving the alarm notification location further away from the end of the stroke.

[0119] (Adjustment of the alarm notification position based on cylinder speed)

[0120] The controller 20 of the embodiment can adjust the alarm notification position by feedback control based on the movement speed of the piston toward the stroke end (referred to as cylinder speed), thereby changing the timing of notifying the operator of the alarm. Figure 9 1 is a flowchart showing the flow of a process for adjusting the alarm notification position based on the cylinder speed.

[0121] like Figure 9 As shown in FIG. 1 , in step S31, the controller 20 receives input of the operation of the operating lever by the operator. In step S32, the controller 20 starts the operation of the working device 3 according to the operation of the operator. In step S33, the controller 20 obtains the current position of the piston. The processing of steps S31 to S33 is the same as that of FIG. Figure 5 The processes of steps S11 to S13 shown are performed in the same manner.

[0122] In step S34 , the controller 20 determines whether the piston has reached the determination position. The alarm notification unit 22 determines whether the piston has reached a predetermined determination position based on the current position of the piston of the hydraulic cylinder obtained by the cylinder stroke calculation unit 21 .

[0123] If it is determined that the piston has not reached the determination position (No in step S34 ), the acquisition of the current position of the piston in step S33 and the determination in step S34 are repeated.

[0124] If it is determined that the piston has reached the determination position (YES in step S34), then in step S35, the controller 20 receives input from the operator's operation amount of the first operating lever 25L and / or the second operating lever 25R from the operation amount sensor 26. In step S36, the controller 20 calculates the cylinder speed based on the operation amount of the lever. In step S37, the controller 20 sets the alarm notification position based on the cylinder speed.

[0125] Figure 10 This diagram illustrates an example of operation when the cylinder speed is high. In step S36, the cylinder speed at time t31, when the piston reaches the judgment position, is acquired. When the cylinder speed is high, the lever operation amount is large, and the lever displacement from the neutral position is large. Therefore, the time from when the operator removes their hand from the lever until the lever returns to the neutral position is longer. Because the piston travels a large distance per unit time, the piston travels a long distance from the time the alarm is notified until the operator, upon recognizing the alarm, reduces the amount of operation on the operating device 25.

[0126] Therefore, the controller 20 sets the position farther from the stroke end as the alarm notification position when the cylinder speed is high. Figure 10In the example, an alarm is issued at time t32. Recognizing the alarm, the operator reduces the amount of operation on operating device 25, causing the piston to begin decelerating at time t33. Time T3 elapses from the alarm being issued until the piston begins decelerating. Through these operations, the piston comes to rest at a distance L from the end of its stroke.

[0127] Figure 11 is a diagram showing an example of the action when the cylinder speed is low. In step S36, the piston reaches the Figure 10 The cylinder speed at time t41, which is the same as the judgment position, is also the same. When the cylinder speed is low, the lever operation amount is small, and the lever displacement from the neutral position is small. Therefore, the time from when the operator removes their hand from the lever to when the lever returns to the neutral position is short. Because the piston travels a short distance per unit time, the piston travels a short distance from the time the alarm is notified until the alarm is recognized and the operator reduces the operation amount of the operating device 25.

[0128] Therefore, when the cylinder speed is low, the controller 20 sets the position closer to the stroke end as the alarm notification position. Figure 11 In the example, the alarm is notified at time t42. The operator who recognizes the alarm reduces the amount of operation of the operating device 25, and starts decelerating the piston at time t43. Time T4 passes from the time the alarm is notified to the time the piston starts decelerating. Figure 10 Likewise, it comes to rest at a distance L from the end of the stroke.

[0129] The controller 20 adjusts the alarm notification position based on the cylinder speed when the piston reaches the judgment position. If the cylinder speed is high, the distance the piston moves from the moment the alarm is notified to the moment the piston begins to decelerate is long. In the case of a high cylinder speed, the timing of the alarm notification is set earlier, thereby suppressing the piston of the hydraulic cylinder from reaching the end of the stroke and reducing noise. If the cylinder speed is low, the distance the piston moves from the moment the alarm is notified to the moment the piston begins to decelerate is short. In the case of a low cylinder speed, the timing of the alarm notification is set later, thereby enabling a larger range of the maximum stroke of the hydraulic cylinder to be used to operate the working device 3, which can improve the efficiency of the operation.

[0130] Figure 9 The processing of steps S38 to S41 shown below is the same as Figure 5 The processes in steps S13 to S16 are the same, and therefore their description is omitted.

[0131] (Travel limit control and its release)

[0132] Next, the stroke limit control will be described. Figure 12 This is a diagram showing an example of an alarm notification position and a stroke limit position.

[0133] As described above, stroke limit control is intervention control by the controller 20 to stop the piston of the hydraulic cylinder before reaching the stroke end. The stroke limit position is set by the stroke limit control to be the position where the piston starts to decelerate, between the alarm notification position and the stroke end.

[0134] exist Figure 12 In the example, an alarm is issued at time t51. The position reached by the piston at time t52 is set as the stroke limit position. When the piston reaches the stroke limit position, the piston begins to decelerate regardless of the operator's operation of the operating device 25. Due to the stroke limit control, the piston stops at a distance L from the stroke end. Figure 12 The distance L shown can be, for example, 5% of the maximum travel.

[0135] Next, a description will be given of control for releasing the stroke limit control so that the piston of the hydraulic cylinder can reach the stroke end as the operator intends during operation. Figure 13 This is a flowchart showing the flow of processing for canceling the stroke limit control according to the intention of the operator during operation.

[0136] Figure 13 The processing of steps S51 to S55 shown in FIG. Figure 5 The processes in steps S11 to S15 are the same, and therefore their description is omitted.

[0137] In step S56 , the controller 20 obtains the current position of the piston in the same manner as in step S53 .

[0138] In step S57 , the controller 20 determines whether the piston has reached the stroke limit position. The stroke limit control unit 23 determines whether the piston has reached a predetermined stroke limit position based on the current position of the piston of the hydraulic cylinder obtained by the cylinder stroke calculation unit 21 .

[0139] If it is determined that the piston has not reached the stroke limit position (No in step S57 ), the acquisition of the current position of the piston in step S56 and the determination in step S57 are repeated.

[0140] If the piston is determined to have reached the stroke limit position (YES in step S57), the controller 20 executes stroke limit control in step S58. The stroke limit control unit 23 sends a control signal to the EPC valve 46 to reduce its opening, thereby decelerating the piston. Closing the EPC valve 46 stops the supply of pilot oil to the main valve 41, halting movement of the spool of the main valve 41. With the piston of the hydraulic cylinder stationary, the operation of the working device 3 ceases.

[0141] After the piston is stationary and the working device 3 stops due to the stroke limit control, the controller 20 determines in step S59 whether the operation of the operating device 25 by the operator is continuing. The operation of the operating device 25 is detected by the operation amount sensor 26. The controller 20 determines whether the operation of the operating device 25 is continuing based on whether the detection result indicating that the operating device 25 is being operated is input from the operation amount sensor 26. If it is determined that the operation of the operating device 25 is not continuing (No in step S59), the processing is terminated as it is ( Figure 13 the end of the ).

[0142] If it is determined that the operation of the operating device 25 continues (yes in step S59), the controller 20 recognizes the continued operation of the operating device 25 as a manifestation of the operator's intention to further move the piston, and thus releases the stroke limit control in step S60. The stroke limit control release unit 24 outputs a control signal to the EPC valve 46 that instructs the valve opening corresponding to the operation amount of the operating device 25 performed by the operator. Pilot oil is supplied to the main valve 41 through the control of the EPC valve 46, and the slide valve of the main valve 41 moves. The action of the working device 3 is reopened by the movement of the piston of the hydraulic cylinder (step S61). When the piston reaches the end of the stroke (step S62), the processing is terminated ( Figure 13 the end of the ).

[0143] Depending on the nature of the work, such as unloading operations, where the piston 4cc of the bucket cylinder 4c reaches the end of its stroke, causing the soil adhering to the bucket 3c to fall, there may be a desire to intentionally move the piston of the hydraulic cylinder to the end of its stroke. This operator's intention is recognized as continued operation of the operating device 25, and the stroke limit control is released. This allows the operator to freely use the end of the stroke when desired, thereby improving workability.

[0144] Figure 14 This is a flowchart showing the flow of processing for canceling the stroke restriction control based on a setting made in advance by the operator.

[0145] like Figure 14 As shown, in step S71, as preparation for the operation, the operator sets the stroke limit control. The operator operates the operating unit 30, specifically the monitor 31 or the switch 32. The operator's operation is input to the stroke limit control setting unit 50, which then sets whether to execute the stroke limit control. The stroke limit control setting unit 50 inputs this setting into the controller 20.

[0146] For example, for an experienced operator, the stroke limit control may be set to not execute, and an alarm may be issued when the piston reaches the alarm notification position, but intervention control by the controller 20 may not be performed. For example, for an inexperienced operator, the stroke limit control may be set to execute, and even if the operator's operation of reducing the amount of operation of the operating device 25 upon receiving an alarm notification is out of control, intervention control by the controller 20 may be used to reliably prevent the piston from reaching the stroke end.

[0147] The processing of steps S72 to S78 is Figure 13 The processes of steps S51 to S57 shown are the same, and therefore their description is omitted.

[0148] In step S79, the controller 20 determines whether the stroke limit control is valid. Based on the pre-set setting in step S71, the controller 20 determines whether the stroke limit control is valid or invalid.

[0149] If the stroke limit control is valid (yes in step S79), then in step S80, the controller 20 executes the stroke limit control to stop the operation of the working device 3. Then, the process ends ( Figure 14 the end of the ).

[0150] If the stroke limit control has been released (No in step S79), then in step S81, the operation of the working device 3 continues according to the operation of the operating device 25 by the operator. When the piston of the hydraulic cylinder reaches the end of the stroke (step S82), the processing is terminated ( Figure 14 the end of the ).

[0151] By configuring the operator to switch execution and stop of the stroke limit control in advance by operating the operating unit 30 , the operator can freely use the stroke end when desired during earthmoving work with the bucket 3 c , thereby improving workability.

[0152] It is also possible to configure the system so that each hydraulic cylinder is set Figure 13 、 14 The stroke limit control shown is switched on and off. Figure 3 The boom restriction portion 23a, the arm restriction portion 23b, and the bucket restriction portion 23c shown may be independently controllable. Figure 3 The boom release unit 24a, arm release unit 24b, and bucket release unit 24c shown may be independently controllable. The stroke limit control setting unit 50 may also set execution or non-execution of the stroke limit control for each of the boom cylinder 4a, arm cylinder 4b, and bucket cylinder 4c.

[0153] For example, the arm 3b may be controlled to limit the stroke of the piston 4bc of the arm cylinder 4b so that it does not reach the end of its stroke, while the bucket 3c may be controlled to stop limiting the stroke of the piston 4bc so that the operator can easily unload the soil from the bucket 3c. By setting the above-described configuration, the generation of noise can be reliably suppressed, and the operability of the work machine 3 can be improved.

[0154] In the above embodiment, the hydraulic excavator 100 includes the controller 20 and the notification device 60, and the controller 20 mounted on the hydraulic excavator 100 controls the notification device 60 to issue an alarm.

[0155] Figure 15 This is a schematic diagram of a system including a work machine. A system may also be configured in which a controller 120, located external to the hydraulic excavator 100, receives signals indicating detection results from the stroke sensors 7a, 7b, and 7c, for example, from the hydraulic excavator 100 and, based on these signals, causes the notification device 60 to issue an alarm. The controller 120 and notification device 60 may be located at the work site of the hydraulic excavator 100 or at a remote location away from the work site of the hydraulic excavator 100.

[0156] While the embodiments have been described above, it is also possible to appropriately combine structures that can be combined with each other in the various embodiments. Furthermore, it should be understood that the embodiments disclosed herein are illustrative and non-restrictive in all respects. The scope of the present invention is not represented by the above description but by the technical solutions, and is intended to include all modifications within the meaning and scope equivalent to the technical solutions.

[0157] Description of reference numerals:

[0158] 1...Traveling unit; 2...Swinging unit; 3...Working device; 3a...Boom; 3b...Arm; 3c...Bucket; 3ce...Shovel tip; 4a...Boom cylinder; 4aa, 4ba, 4ca...Cylinder; 4ab, 4bb, 4cb...Rod; 4ac, 4bc, 4cc...Piston; 4b...Arm cylinder; 4c...Bucket cylinder; 7a, 7b, 7c...Stroke sensor; 9a, 9b, 9c...Angle sensor; 20, 120...Control 1… 1. a cylinder stroke calculating unit; 21… 1. an alarm notifying unit; 22… 1. a stroke limiting control unit; 23… 1. a stroke limiting control releasing unit; 24… 1. an operating device; 25L… 1. a first operating lever; 25R… 2. a second operating lever; 26… 1. an operating amount sensor; 30… 1. an operating unit; 31… 1. a monitor; 32… 1. a switch; 41… 1. a main valve; 46… 1. an EPC valve; 50… 1. a stroke limiting control setting unit; 60… 1. a notification device; 61… 1. a lamp; 62… 1. a buzzer; 63… 1. a vibrating body; 100… 1. a hydraulic excavator.

Claims

1. A working machine, wherein: The operating machine comprises: body; a working device supported on the vehicle body; a hydraulic cylinder having a cylinder portion and a piston capable of reciprocating in the cylinder portion, for driving the working device; a notification device that notifies an alarm; as well as a controller that controls the hydraulic cylinder and the notification device, The controller causes the notification device to notify an alarm when the piston reaches an alarm notification position closer to the stroke end of the hydraulic cylinder. The controller can adjust the alarm notification position based on the proficiency of the operator operating the work machine, thereby adjusting the timing of the alarm notification.

2. The working machine according to claim 1, wherein: The working machine further includes an operating device operated by an operator to drive the hydraulic cylinder. The controller recognizes the operator's proficiency based on a time period from when an alarm is notified to when the amount of operation of the operating device starts to decrease.

3. The working machine according to claim 1, wherein: The controller recognizes the proficiency of the operator based on the rest position of the piston after the notification device notifies of the alarm.

4. A working machine, wherein: The operating machine comprises: body; a working device supported on the vehicle body; a hydraulic cylinder having a cylinder portion and a piston capable of reciprocating in the cylinder portion, for driving the working device; a notification device that notifies an alarm; as well as a controller that controls the hydraulic cylinder and the notification device, The controller causes the notification device to notify an alarm when the piston reaches an alarm notification position closer to the stroke end of the hydraulic cylinder. The controller is capable of adjusting the timing of alarm notifications, The working machine further includes an operating device operated by an operator to drive the hydraulic cylinder. The controller performs stroke limiting control for decelerating the piston when the piston reaches a stroke limiting position between the alarm notification position and the stroke end. After the piston comes to rest by the stroke limit control, if the operation of the operating device continues, the controller releases the stroke limit control.

5. A working machine, wherein: The operating machine comprises: body; a working device supported on the vehicle body; a hydraulic cylinder having a cylinder portion and a piston capable of reciprocating in the cylinder portion, for driving the working device; a notification device that notifies an alarm; as well as a controller that controls the hydraulic cylinder and the notification device, The controller causes the notification device to notify an alarm when the piston reaches an alarm notification position closer to the stroke end of the hydraulic cylinder. The controller is capable of adjusting the timing of alarm notifications, The controller performs stroke limiting control for decelerating the piston when the piston reaches a stroke limiting position between the alarm notification position and the stroke end. The working machine further includes an operating unit for an operator to operate switching between execution and stop of the stroke limiting control of the hydraulic cylinder.

6. The working machine according to claim 5, wherein: The working device includes a boom rotatable relative to the vehicle body, an arm rotatable relative to the boom, and an attachment rotatable relative to the arm. The hydraulic cylinder includes a first cylinder for driving the boom and a second cylinder for driving the accessory. The controller is capable of switching execution and stop of the stroke limit control of the first cylinder and execution and stop of the stroke limit control of the second cylinder, respectively.

7. A system comprising a work machine, wherein: The system including the working machine comprises: A working machine including a vehicle body, a working device supported by the vehicle body, and a hydraulic cylinder having a cylinder portion and a piston capable of reciprocating in the cylinder portion and driving the working device; a notification device that notifies an alarm; as well as a controller that controls the hydraulic cylinder and the notification device, The controller causes the notification device to notify an alarm when the piston reaches an alarm notification position closer to the stroke end of the hydraulic cylinder. The controller can adjust the alarm notification position based on the proficiency of the operator operating the work machine, thereby adjusting the timing of the alarm notification.

8. A method for controlling a notification device for notifying an alarm related to a working machine, the working machine comprising a vehicle body, a working device supported by the vehicle body, and a hydraulic cylinder having a cylinder portion and a piston capable of reciprocating in the cylinder portion and driving the working device, wherein: When the piston reaches an alarm notification position closer to the stroke end of the hydraulic cylinder, the notification device is caused to notify an alarm. The alarm notification position can be adjusted based on the proficiency of the operator operating the work machine, thereby adjusting the timing of the alarm notification.

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