Working machinery

Abstract

To provide a work machine that can achieve both avoidance of interference between the front work equipment and the operator's cab, and reduction of the operator's operational effort. [Solution] The hydraulic excavator is equipped with a lifting switch 44 for operating the lifting and lowering of the cab 50, a front work implement 103, operating lever devices 4a to 4g, and a controller 45 that controls the lifting and lowering of the cab 50 and the working operation of the front work implement 103 based on the rotation angle detected by angle sensors 31p, 31q, 31r and the rotation angle of the parallel link mechanism 63 detected by link angle sensor 41. The controller 45 controls the lifting and lowering of the cab 50 when lifting and lowering is being performed via the lifting switch 44, when working operation is being performed via the operating lever devices 4a to 4g, or when the distance D between the cab 50 and the front work implement 103 is less than or equal to a first value D1.

Description

Technical Field

[0001] The present invention relates to a work machine equipped with a cab that can be raised and lowered on a vehicle body.

Background Art

[0002] Patent Document 1 discloses a work machine including a vehicle body having a working device, a cab supported by the vehicle body in a state where the posture can be changed between a first posture and a second posture, a first actuator that drives the working device by supplying and discharging hydraulic oil, a second actuator that changes the posture of the cab by supplying and discharging hydraulic oil, a shut-off operation unit that is operated to an allowable position that allows the supply of hydraulic oil to the first actuator and a blocking position that blocks the supply of hydraulic oil to the first actuator, a lock operation unit that is operated to a lock position that locks the posture change of the cab and a release position that releases the lock of the posture change of the cab, a posture operation unit that instructs the posture change of the cab, a notification device that notifies information, and a controller. In the work machine, the controller supplies hydraulic oil to the second actuator to change the posture of the cab in response to all of a first condition that the shut-off operation unit is in the blocking position, a second condition that the lock operation unit is in the release position, and a third condition that the posture operation unit is operated, and the third condition was last satisfied, and supplies hydraulic oil to the second actuator in response to the first condition or the second condition being last satisfied, and notifies through the notification device that the operation procedure for changing the posture of the cab without supplying hydraulic oil to the second actuator is incorrect.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the case of a work machine equipped with a movable cab, it is necessary to prevent the operation of the front work machine and the operation of the cab from being performed simultaneously in order to avoid interference between the front work machine and the cab. For this purpose, Patent Document 1 provides a switch for moving the cab, a lock switch for switching between a state in which the front work machine can be operated and a state in which the cab can be operated, and a shut-off lever.

[0005] In Patent Document 1, when the shut-off lever is in the permissible position, the front work implement can operate regardless of the state of the lock switch, while the operation of the operator's cab is prohibited and the system is stopped. Furthermore, if the shut-off lever is in the blocked position and the lock switch is in the locked position, both the operation of the front work implement and the operation of the operator's cab are prohibited, and the machine is brought to a stopped state. Furthermore, if the shut-off lever is in the blocked position and the lock switch is in the released position, the operation of the front work implement will be prohibited and the machine will be stopped, but the operation of the operator's cab will still be possible.

[0006] However, in the above-mentioned Patent Document 1, when the operator wants to switch between a state where the front work implement is operational and a state where the operator's cab is operational, the operator needs to operate both a shut-off lever and a lock switch. Therefore, the operational burden on the operator is significant, and the work must be interrupted each time.

[0007] To address this issue, one could consider simplifying operator operation by omitting the lock switch. In this case, both the cab operation and the front work implement operation would be possible without switching, reducing the operator's workload and improving work efficiency. However, this would increase the risk of interference between the front work implement and the vehicle body.

[0008] This invention has been made in view of the above circumstances, and its purpose is to provide a work machine that can achieve both avoidance of interference between the front work machine and the operator's cab, and reduction of the operator's labor. [Means for solving the problem]

[0009] To achieve the above objective, the present invention provides a work machine comprising: a vehicle body; a driver's cab provided on the vehicle body so as to be able to move up and down; a lifting switch for operating the lifting and lowering operation of the driver's cab; a position detection device for detecting position information of the driver's cab; a front work machine mounted on the vehicle body so as to be able to move up and down; an operating lever for operating the work operation of the front work machine; a posture detection device for detecting posture information of the front work machine; and a controller that controls the lifting and lowering operation of the driver's cab and the work operation of the front work machine based on the position information detected by the position detection device and the posture information detected by the posture detection device, wherein the controller controls the lifting and lowering operation of the driver's cab when the lifting and lowering operation is being operated via the lifting switch, when the work operation is being operated via the operating lever, or when the distance between the driver's cab and the front work machine, determined based on the position information detected by the position detection device and the posture information detected by the posture detection device, is less than or equal to a predetermined value. [Effects of the Invention]

[0010] According to the present invention, it is possible to achieve both avoidance of interference between the front work equipment and the driver's cab, and a reduction in the operator's operational effort. [Brief explanation of the drawing]

[0011] [Figure 1] This is a diagram illustrating a hydraulic excavator according to one embodiment of the present invention. [Figure 2] This diagram shows the raising and lowering operation of the cab. [Figure 3] This is a hydraulic circuit diagram showing the hydraulic drive system installed in a hydraulic excavator. [Figure 4] This is a view of the driver's cab from above, and a close-up view of the left console device. [Figure 5] This is an explanatory diagram of the operating restriction area related to proximity cab stop control. [Figure 6] This flowchart illustrates the processes involved in proximity cab stop control and priority cab stop control, which are performed by the controller. [Figure 7] This is an explanatory diagram illustrating a method for calculating the distance between the front attachment and the cab. [Figure 8] This diagram shows the calculation table stored in the controller. [Figure 9] This is a time chart illustrating an example of cab operation when priority cab stop control and proximity cab stop control are performed by the controller. [Modes for carrying out the invention]

[0012] One embodiment of the present invention will be described below with reference to the drawings.

[0013] <Overall configuration of the work machine> Figure 1 shows a working machine with a movable cab according to one embodiment of the present invention. In this embodiment, a hydraulic excavator, a typical example of construction machinery, will be used as the working machine for explanation.

[0014] In Figure 1, the cab-movable hydraulic excavator comprises a vehicle body 100 equipped with a movable cab (operator's cabin; hereinafter simply referred to as "cab" as appropriate) 50 that can be raised and lowered, and a front work implement 103 that is rotatably connected to the vehicle body 100 and fitted with a front attachment 106. The vehicle body 100 has a lower traveling body 110 and an upper rotating body 111 that is rotatably mounted on the lower traveling body 110.

[0015] The front working machine 103 has a boom 104 that is vertically rotatably attached to the upper swing body 111, and an arm 105 that is attached to the tip of the boom 104 so as to be rotatable in the vertical and front-rear directions. The front attachment 106 is attached to the tip of the arm 105 so as to be rotatable in the vertical and front-rear directions. The boom 104 is driven by a boom cylinder 3a (see FIG. 5 described later), the arm 105 is driven by an arm cylinder 3b, and the front attachment 106 is driven by an attachment cylinder 3c.

[0016] The upper swing body 111 is driven by a swing motor 3e (see FIG. 3 described later) and swings on the lower traveling body 110. The lower traveling body 110 has left and right crawlers 110a and 110b (not shown in FIG. 1), and the left and right crawlers 110a and 110b are respectively driven by left and right traveling motors 3f and 3g (not shown in FIG. 1; see FIG. 3 described later) to perform traveling.

[0017] The cab 50 is attached to the front side position on the swing frame 111a of the upper swing body 111 so as to be vertically movable with respect to the upper swing body 111. An elevating device 60 for elevating the cab 50 with respect to the vehicle body 100 is disposed between the upper swing body 111 and the cab 50.

[0018] The elevating device 60 includes a tower-shaped support frame 61 erected on the swing frame 111a of the upper swing body 111, an L-shaped pedestal 62 integrally attached to the lower part of the cab 50, an upper end portion 61a of the tower-shaped support frame 61 and a rear stay 62a of the pedestal 62 are pivotally connected by pins, and a parallel link mechanism 63 composed of two links that keep the cab 50 horizontal, and a lower side of the parallel link mechanism 63 and an upper end portion of the support frame 61 and a rear stay 62a of the pedestal 62 are pivotally connected by pins, and an elevating cylinder 64 for moving the cab 50 in the vertical direction.

[0019] The tower-shaped support frame 61 and the lifting cylinder 64 are each composed of a left and right pair, and the parallel link mechanism 63 is connected between the left and right pair of tower-shaped support frames 61 and the upper end portion of the support frame 61 and the rear stay 62a of the frame 62.

[0020] In this embodiment, the front attachment 106 is a fork grapple that uses an openable and closable fork to grasp waste such as concrete fragments and transport and load them onto the bed of a truck. The front attachment 106 may also be other work tools such as a bucket equipped with digging claws or a lifting magnet that attracts and transports waste such as iron scrap using the magnetic force of an electromagnet.

[0021] <Cab's raised / lowered position> Figure 2 shows the state in which the cab 50 is raised and lowered. Note that the front work implement 103 is omitted from Figure 2 to avoid complexity in the illustration. When the lifting cylinder 64 of the lifting device 60 is extended and retracted, the parallel link mechanism 63 rotates around the connecting pin of the support frame 61 as a pivot point, and the cab 50 is raised and lowered by the rotation of this parallel link mechanism 63.

[0022] The cab 50 shown in the upper part of Figure 2 represents the state where the lifting cylinder 64 is fully extended and the cab 50 is in its highest position. The cab 50 shown in the lower part of Figure 2 represents the state where the lifting cylinder 64 is fully retracted and the cab 50 is in its lowest position. Furthermore, when the cab 50 is raised and lowered, the parallel link mechanism 63 rotates around the connecting pin of the support frame 61 as a pivot point due to the extension and retraction of the lifting cylinder 64, and moves in the front-rear direction as well. At an intermediate position between the lowest and highest positions, it is in its furthest forward position (extended position).

[0023] A hydraulic excavator equipped with a cab 50 can perform surface work such as excavation, just like a typical hydraulic excavator, when the cab 50 is lowered to its lowest position. On the other hand, when the cab 50 is raised to its highest position, the operator's line of sight is elevated, allowing them to work while viewing the interior of large containers such as trunks or containers with a wider field of view.

[0024] Here, for example, when the cab 50 is raised or lowered between its highest and lowest positions, the front work implement 103, particularly the front attachment 106, may come into contact with (interfere with) the cab 50. This embodiment provides a technique to avoid such contact between the front attachment 106 and the cab 50 when the cab is raised or lowered.

[0025] <Hydraulic drive system> Figure 3 is a hydraulic circuit diagram showing the hydraulic drive system mounted on the hydraulic excavator in this embodiment.

[0026] In Figure 3, the hydraulic drive system of the hydraulic excavator in this embodiment includes a hydraulic pump 2 as the main pump, a plurality of actuators including the boom cylinder 3a, arm cylinder 3b, attachment cylinder 3c, slewing motor 3e, and left and right travel motors 3f and 3g, which are driven by the pressurized oil from the hydraulic pump 2, operating lever devices 4a to 4g provided corresponding to each of these hydraulic actuators 3a to 3g, a plurality of control valves 5a to 5g connected between the hydraulic pump 2 and the plurality of hydraulic actuators 3a to 3g, and a main relief valve 6 as a safety valve. The control valves 5a to 5g are switched from the neutral position by the command pilot pressure of the operating lever devices 4a to 4g, and control the flow direction and flow rate of the pressurized oil (the driving direction and driving speed of the hydraulic actuators 3a to 3g).

[0027] The operating lever devices 4a to 4g are hydraulically piloted with built-in pressure reducing valves and are connected to the discharge oil passage 7a of the pilot pump 7 via the pilot pressure supply oil passage 7b. Based on the hydraulic pressure (primary pressure) generated by the pilot pump 7, the operating lever devices 4a to 4g generate command pilot pressure (secondary pressure) corresponding to the amount and direction of operation of the operating lever operated by the operator. These command pilot pressures are led to the pressure receiving sections 20a, 20b to 26a, 26b of the corresponding control valves 5a to 5g via pilot lines 10a, 10b to 16a, 16b. The discharge oil passage 7a of the pilot pump 7 is provided with a pilot relief valve 8 that maintains a constant discharge pressure of the pilot pump 7.

[0028] Furthermore, the hydraulic drive device of this embodiment further includes a lifting cylinder 64 (lifting hydraulic cylinder) of the lifting device 60 described above, and a lifting control valve 65 (pilot-operated control valve) connected between the hydraulic pump 2 and the plurality of lifting cylinders 64, which controls the flow direction and flow rate of pressurized oil (driving direction and driving speed of the lifting cylinders 64). The lifting cylinder 64 is driven to move the cab 50 downwards by supplying hydraulic fluid to the rod side and retracting it, and is driven to move the cab 50 upwards by supplying hydraulic fluid to the bottom side and extending it. The lift control valve 65 is a pilot-operated control valve that switches from a neutral position to a desired open position when the control pilot pressure generated in the pilot lines 66a and 66b acts on the pressure receiving sections 65a and 65b in response to the operation of the lift switch 44 (described later) (hereinafter referred to as "lift operation" as appropriate). The pilot lines 66a and 66b are pipelines that branch off from the upstream side of the shut-off electromagnetic switching valve 120 in the pilot pressure supply oil passage 7b and communicate with the pilot pressure supply oil passage 7c.

[0029] Furthermore, the hydraulic drive system of this embodiment includes pressure sensors 31p, 31b, 31l, and 31m that detect the operating pressure of pilot lines 10a, 10b to 16a and 16b respectively, angle sensors 31p, 31q, and 31r (attitude detection devices) provided at the pivot points of the boom 104, arm 105, and front attachment 106 respectively, a link angle sensor 41 (position detection device) mounted coaxially with the pivot point of the parallel link mechanism 63 on the tower-shaped support frame 61, a shut-off lever 43, a lifting switch 44 that instructs the raising and lowering of the cab 50, a controller 45, an electromagnetically switching type shut-off valve 34 positioned between the discharge oil passage 7a and the pilot pressure supply oil passage 7b of the pilot pump 7, and a pilot pump that responds to command signals from the controller 45. The system includes an emergency stop electromagnetic switching valve 80 for switching between opening and closing the pilot pressure supply oil passage 7b, electromagnetic proportional pressure reducing valves 33a, 33b, and 33c provided on pilot lines 10a, 11a, and 12a, an electromagnetic proportional control valve 36 provided on pilot line 17 branched from pilot pressure supply oil passage 7b, a shuttle valve 37 that selects the higher of the pressure of the arm dump pilot line 11b (output pressure of the operating lever device 4b) and the output pressure of the electromagnetic proportional control valve 36 and outputs it to pilot line 11b, electromagnetic proportional control valves 67a (first electromagnetic proportional valve) and electromagnetic proportional control valve 67b (second electromagnetic proportional valve) provided on pilot line 66a (one-side pilot pipeline) and pilot line 66b (the other-side pilot pipeline), a monitor 46, and a warning buzzer 47.

[0030] The angle sensors 31p, 31q, and 31r detect their respective rotation angles as state variables (attitude information) related to the position and attitude of the front work implement 103. Alternatively, instead of the angle sensors 31p, 31q, and 31r, inertial sensors may be used as attitude detection devices to detect the position and attitude of the front work implement 103. The link angle sensor 41 detects the rotation angle of the parallel link mechanism 63 as a state quantity (position information) related to the height position of the cab 50. Alternatively, instead of the link angle sensor 41, a stroke sensor that detects the stroke of the lifting cylinder 64 may be used as a position detection device to detect the state quantity related to the height position of the cab 50.

[0031] The controller 45 receives sensor signals from angle sensors 31p, 31q, 31r and link angle sensor 41, as well as switch signals from the shut-off lever 43 and lift switch 44, and performs calculation processing to execute various controls (see Figure 6 below).

[0032] The shut-off lever 43, the lifting switch 44, the monitor 46, and the warning buzzer 47 are installed in the driver's cabin of the cab 50.

[0033] The shut-off lever 43 can be switched between a locked position and an unlocked position by the operator. When switched to the locked position, the shut-off valve 34 blocks the discharge oil passage 7a and the pilot pressure supply oil passage 7b of the pilot pump 7, cutting off the pilot pressure (reducing it to tank pressure), thereby disabling the operation of the above-mentioned operating lever devices 4a to 4g. When switched to the unlocked position, the discharge oil passage 7a and the pilot pressure supply oil passage 7b are connected, and the operation of the operating lever devices 4a to 4g becomes active. This shut-off lever 43 is used, for example, when stopping work and parking the hydraulic excavator.

[0034] The lifting switch 44 is a switch that instructs the raising and lowering of the cab 50, and includes an upward indicator switch 44a to raise the cab 50 and a downward indicator switch 44b to lower it. These indicator switches 44a and 44b are momentary type switches that are ON only while pressed and have an automatic return mechanism.

[0035] The electromagnetic proportional pressure reducing valves 33a, 33b, and 33c reduce the command pilot pressure generated by the operating lever devices 4a, 4b, and 4c in response to an electrical signal from the controller 45, and the reduced command pilot pressure is guided via the pilot lines 10a, 11a, and 12a to the pressure receiving sections 20a, 21a, and 22a of the control valves 5a, 5b, and 5c.

[0036] The electromagnetic proportional control valve 36 generates a control pilot pressure (secondary pressure) in response to an electrical signal from the controller 45, based on the hydraulic pressure (primary pressure) generated by the pilot pump 7. This control pilot pressure is then guided to the pressure-receiving section 21b of the arm dump of the control valve 5b via the shuttle valve 37 and the pilot line 11b. The pilot line 11b and the shuttle valve 37 constitute a pilot circuit that guides the output pressure of the electromagnetic proportional control valve 36 to the pressure-receiving section 21b of the arm dump of the control valve 5b of the arm 105.

[0037] The electromagnetic proportional control valves 67a and 67b generate a control pilot pressure (secondary pressure) in response to an electrical signal from the controller 45 corresponding to the lifting operation of the lifting switch 44, based on the hydraulic pressure (primary pressure) generated by the pilot pump 7 and guided through the pilot pressure supply oil passage 7c. This control pilot pressure is then guided to the pressure receiving sections 65a and 65b of the lifting control valve 65 via the pilot lines 66a and 66b.

[0038] <Driver's cab> Here, Figure 4(a) shows a view of the driver's cab inside the cab 50 from above. As shown in Figure 4(a), the driver's cab is equipped with a driver's seat 160 where the operator sits. A left console device 161 is provided on the entrance side of the cab 50, that is, to the left of the driver's seat 160. A right console device 124 is provided on the opposite side, to the right of the driver's seat 160.

[0039] The right console device 124 has an operating lever 125. In this example, operating the operating lever 125 forward and backward instructs the boom cylinder 3a to lower and raise the boom, while operating the operating lever 125 to the right and left instructs the attachment cylinder 3c to dump and cloud. In other words, the operating lever 125 functions as the operating lever for the operating lever devices 4a and 4c described above using Figure 3.

[0040] The left console device 161 includes an operating lever 114, the shut-off lever 43, and a switch box 167 equipped with multiple switches. An enlarged view of the left console device 161 is shown in Figure 2(b). In Figure 2(a), moving the operating lever 114 to the right and left instructs the arm cloud and arm dump movements of the arm cylinder 3b, while moving the operating lever 114 forward and backward instructs the right and left rotation movements of the slewing motor 3d. In other words, the operating lever 114 functions as the operating lever for the operating lever devices 4b and 4d described above using Figure 3. In this example, the lift switch 44 is located in the front area of ​​the switch box 167.

[0041] Although not shown in the illustration, a pair of left and right operating levers 4f and 4g (see Figure 3 above) are located in front of the driver's seat 160, which can be operated by the operator with their left and right feet or left and right hands. Operating the left operating lever 4f forward and backward instructs the left travel motor 3f to move forward and backward, while operating the right operating lever 4g forward and backward instructs the right travel motor 3g to move forward and backward.

[0042] <Features of the Embodiment> The key feature of this embodiment is achieving both the avoidance of interference between the front work implement 103 and the cab 50, and the reduction of the operator's operational effort required to achieve this.

[0043] <Proximity cab stop control> In this embodiment, in order to achieve both of the above, first, when the cab 50 and the front work implement 103 become close together during the lifting operation by the lifting switch 44, control is performed to stop the lifting operation of the cab 50 (hereinafter referred to as "proximity cab stop control" as appropriate).

[0044] <Operational Restriction Area> The operation restriction area 70 related to proximity cab stop control will now be explained.

[0045] As shown in Figure 5, the operating restriction area 70 is set on the front, top, and bottom sides of the cab 50. The operating restriction area 70 also has a stop area B and an emergency stop area A, and the stop area B and emergency stop area A are located in that order from the outside to the inside of the cab 50. When the front attachment 106 enters the stopping area B, the controller 45 drives the electromagnetic proportional control valves 67a and 67b to reduce the command pilot pressure and gradually decelerate the lifting and lowering movement of the cab 50. Finally, the controller 45 fully closes the electromagnetic proportional control valves 67a and 67b to control the lifting control valve 65 to the neutral position and stop the lifting and lowering movement of the cab 50. When the front attachment 106 enters the emergency stop area A, the controller 45 immediately closes the electromagnetic proportional control valves 67a and 67b completely, controls the lift control valve 65 to the neutral position, and stops the lifting and lowering operation of the cab 50. The controller 45 also notifies the monitor 46 and warning buzzer 47 that the proximity cab stop control is being performed.

[0046] Although not shown in the diagram, a restricted area is set further inside the emergency stop area A. If the front attachment 106 enters this restricted area, the controller 45 will close the electromagnetic proportional control valves 67a and 67b completely, as described above, to stop the lifting and lowering operation of the cab 50, and will also switch the emergency stop electromagnetic switching valve 80 to cut off communication between the discharge oil passage 7a of the pilot pump 7 and the pilot pressure supply oil passage 7b. This will forcibly stop all operations of the hydraulic excavator.

[0047] <Priority Cab Stop Control> Furthermore, in this embodiment, in order to achieve both of the above, if an operation for work using the front work implement 103 is performed while the cab is being raised or lowered by the lifting switch 44, control is performed to stop the raising or lowering of the cab 50 in order to prioritize the operation of the front work implement 103 (hereinafter referred to as "priority cab stop control" as appropriate). The controller 45 also notifies the monitor 46 and warning buzzer 47 that the priority cab stop control is being performed.

[0048] <Control Flow> Figure 6 is a flowchart showing the processing details related to the proximity cab stop control and priority cab stop control performed by the controller 45.

[0049] In Figure 6, first in S5, it is determined whether the shut-off lever 43 is switched to the unlocked position. If the shut-off lever 5 is in the locked position, the result is No, and the process proceeds to S40, which will be described later. If the shut-off lever 43 is in the unlocked position, S5 is determined to be Yes, and the process proceeds to S10.

[0050] In S10, it is determined whether the lift switch 44 is being operated. If the lift switch 44 is not being operated, the result is No, and this flow ends. If the lift switch 44 is being operated, the result is Yes, and the process proceeds to S15.

[0051] In S15, based on the detection results of pressure sensors 31p, 31b~31l, and 31m, it is determined whether or not operations for various work movements using the front work implement 103 (including the rotation movement of the upper rotating body 111) (i.e., operations of the operating lever devices 4a~4c, 4e; hereinafter referred to as "work operations") have been performed. If the above work operations have been performed, S15 is determined to be Yes, and the process proceeds to S35 described below. If none of the operations have been performed, S15 is determined to be No, and the process proceeds to S20.

[0052] In S20, the position of the cab 50 (height position and front-to-back position) is calculated based on the detection result of the link angle sensor 41 (rotation angle of the parallel link mechanism 63). In detail, the height position of the cab 50 is calculated from the rotation angle of the parallel link mechanism 63 detected by the link angle sensor 41 and the dimensions of the parallel link mechanism 63 stored in the controller 45's memory (e.g., ROM). It is preferable to calculate the height of the cab 50 by, for example, the height of the underside of the cab 50.

[0053] In S20, the posture of the front work implement 103 is calculated based on the detection results of angle sensors 31p, 31q, and 31r (rotation angles of boom 104, arm 105, and front attachment 106). In detail, the distance D between the front attachment 106 and the cab 50 is calculated from the rotation angles of the boom 104, arm 105, and front attachment 106 detected by angle sensors 31p, 31q, and 31r, and the dimensions of each front component and the cab 50 which are stored in memory (e.g., ROM) beforehand.

[0054] <Details of the method for calculating distance D> Figure 7 is an explanatory diagram illustrating the method for calculating the distance D between the front attachment 106 and the cab 50.

[0055] In Figure 7, the fork grapple, which is the front attachment 106, is equipped with a bracket 106a, which is rotatably pin-connected to the tip of the arm 105 by a pin 106b. The pin 106b serves as the pivot point for the lifting magnet. At this time, one end of the attachment link 106c is rotatably pin-connected to the bracket 106a by a pin 106d. In addition, one end of the arm link 105a is rotatably pin-connected to the arm 105, and the piston rod of the arm cylinder 3c is rotatably pin-connected to the other end of the attachment link 106c and the other end of the arm link 105a. The rotation angle of the front attachment 106 relative to the arm 105 is detected by the angle sensor 31r.

[0056] The distance D between the front attachment 106 and the cab 50 is calculated as the distance between a representative point of the front attachment 106 and the reference contour line CR of the cab 50. The reference contour line CR is a virtual contour line of the cab 50 used in the proximity cab stop control and priority cab stop control of this embodiment, which is set around the cab 50 taking into account any protrusions on the cab 50.

[0057] As a representative point of the front attachment 106, a virtual circle SC is set as a virtual circle encompassing the front attachment 106, for example, passing through pin 106b of bracket 106a (the pivot point of the front attachment 106 at the tip of arm 105) and another pin 106d, and the point R closest to the cab 50 on this virtual circle SC is set. The position of the nearest contact point R is calculated when the front attachment 106 is operated toward the cab 50, based on the detected value of the angle sensor 31r, the height of the cab 50 calculated as described above, and the dimensions of the front attachment 106 including the cab 50 and bracket 106a, which are stored in memory (e.g., ROM) beforehand. This calculation is performed as the position on the virtual circle SC that is closest to the reference contour line CR of the cab 50, i.e., the position on the virtual circle SC where the distance D between the virtual circle SC and the reference contour line CR of the cab 50 is smallest.

[0058] Furthermore, the distance D between the front attachment 106 and the cab 50 is calculated as the distance between the nearest point R of the virtual circle SC and the reference contour line CR of the cab 50, i.e., the nearest point distance.

[0059] Furthermore, the virtual circle used to define the representative point of the front attachment 106 is not limited to the virtual circle SC passing through the pivot points pins 106b and 106d, but may be any other virtual circle that encompasses the front attachment 106. For example, another virtual circle may be an envelope circle that includes the pivot point pin 106b as part of its arc and encompasses the entire front attachment 106.

[0060] Here, the position of the nearest contact point R of the front attachment 106 can be calculated as a coordinate value in an XY coordinate system with the origin at an appropriate location on the upper slewing body 111, for example, the pivot point at the base end of the boom 104. The X axis of the XY coordinate system is the horizontal axis (parallel to the main surface of the slewing frame 111a of the upper slewing body 111), and the Y axis is the vertical axis (perpendicular to the main surface of the slewing frame 111a of the upper slewing body 111). In this case, the height of the lower surface of the cab 50 is calculated as the coordinate value of the Y axis of the XY coordinate system.

[0061] Once the calculations in S20 are complete, proceed to S25.

[0062] In S25, based on the calculation result of the distance D in S20, it is determined whether the front work implement 103 (specifically, for example, the front attachment 106) has entered the emergency stop area A. If it has not entered the emergency stop area A, the result is No, and the process proceeds to S30.

[0063] In S30, based on the calculation result of the distance D in S20, it is determined whether or not the front work implement 103 (specifically, for example, the front attachment 106) has entered the stopping area B. If it has not entered the stopping area B, it is determined to be No, and the process proceeds to S50.

[0064] Figure 8 shows the calculation table used in S50 (and S40, S60 described later). This calculation table is pre-stored in the memory (e.g., ROM) of the controller 45.

[0065] In Figure 8, the horizontal axis represents the distance D between the front attachment 106 and the cab 50, calculated in S20, and the vertical axis represents the front-to-rear pressure ratio Rp of the electromagnetic proportional control valves 67a and 67b. The distance D between the front attachment 106 and the cab 50 is calculated as the nearest distance between the virtual circle SC of the front attachment 106 and the reference contour line CR of the cab 50, as described above.

[0066] In the calculation table in Figure 8, the relationship between distance D and the front-to-back pressure ratio Rp is set such that when distance D is greater than or equal to the first value D1, the front-to-back pressure ratio Rp is 100%, and when distance D falls below the first value D1 (a predetermined value), the pressure ratio Rp gradually decreases from 100%, and becomes 0% when distance D reaches the second value D2 (a predetermined threshold). The first value D1 corresponds to the boundary position between the non-interference prevention area and the stop area B of the operation restriction area 70, and the second value D2 corresponds to the boundary position between the stop area B and the emergency stop area A. On the side smaller than the second value D2 (closer to the origin) there is a third value D3. This third value D3 corresponds to the boundary position between the emergency stop area A and the prohibited area (not shown).

[0067] In S50 (and S40, S60 described later), the controller 45 reads the calculation table shown in Figure 8 from memory, refers to the distance D (nearest point distance) calculated in S20 in the calculation table to calculate the front-to-back pressure ratio Rp of the electromagnetic proportional control valves 67a and 67b, and outputs a control current corresponding to this front-to-back pressure ratio Rp as an electrical signal to the electromagnetic proportional control valves 67a and 67b.

[0068] In other words, in S50, since distance D > the first value D1, the controller 45 calculates 0% as the front-to-rear pressure ratio Rp and outputs a control current equivalent to a front-to-rear pressure ratio of 100% as an electrical signal to the electromagnetic proportional control valves 67a and 67b. In this case, the electromagnetic proportional control valves 67a and 67b are fully open (not driven), and the cab 50 is driven up and down without restriction at a speed corresponding to a predetermined command pilot pressure. After S50 is complete, this flow ends, and the process returns to S5, repeating the same steps.

[0069] On the other hand, if the above operation is performed in S15 and S15 is judged as Yes, the process proceeds to S35 (if the process then proceeds to S60, it corresponds to priority cab stop control). Also, if the front work implement 103 (specifically, for example, the front attachment 106) enters the stop area B in S30 and is judged as Yes, the process proceeds to S35.

[0070] In S35, for example, based on the detection result of the link angle sensor 41 mentioned above, it is determined whether or not the cab 50 is moving up or down. If the cab 50 is not moving up or down, it is determined to be No, and this flow ends, returning to S5 and the same procedure is repeated. If the cab 50 is moving up or down, it is determined to be Yes, and the process proceeds to S60.

[0071] In S60, similar to S50 above, the calculation table shown in Figure 8 is read from memory, the distance D calculated in S20 is referenced in the calculation table to calculate the pressure ratio Rp across the electromagnetic proportional control valves 67a and 67b, and the corresponding control current is output to the electromagnetic proportional control valves 67a and 67b. In other words, in S60, the second value D2 < distance D ≤ first value D1, so the controller 45 calculates a value corresponding to the distance D as the front-to-rear pressure ratio Rp, and outputs a control current corresponding to this front-to-rear pressure ratio Rp as an electrical signal to the electromagnetic proportional control valves 67a and 67b. As a result, the electromagnetic proportional control valves 67a and 67b reduce the command pilot pressure, and the raising and lowering operation of the cab 50 is slowed down. After a predetermined time has elapsed, the controller 45 outputs a control current corresponding to a 0% front-to-rear pressure ratio as an electrical signal to the electromagnetic proportional control valves 67a and 67b. As a result, the electromagnetic proportional control valves 67a and 67b close completely, reducing the command pilot pressure to the tank pressure and stopping the raising and lowering operation of the cab 50.

[0072] The processing flow from S15 or S30 through S35 to S760 corresponds to the control that stops the raising and lowering operation of the driver's cab as described in each claim.

[0073] After S60 is complete, this flow ends, and the process returns to S5, repeating the same steps.

[0074] On the other hand, if the shut-off lever 5 is in the locked position in S5 and a No determination is made, or if the front work implement 103 (specifically, for example, the front attachment 106) has entered the emergency stop area A in S25 and a Yes determination is made, the process proceeds to S40. In S40, similar to S50 and S60 above, the calculation table shown in Figure 8 is read from memory, the distance D calculated in S20 is referenced in the calculation table to calculate the pressure ratio Rp across the electromagnetic proportional control valves 67a and 67b, and the corresponding control current is output to the electromagnetic proportional control valves 67a and 67b. In other words, in S40, the distance D ≤ the second value D2, so the controller 45 calculates 0% as the front-to-rear pressure ratio Rp and outputs a control current corresponding to a front-to-rear pressure ratio of 0% as an electrical signal to the electromagnetic proportional control valves 67a and 67b. As a result, the electromagnetic proportional control valves 67a and 67b are completely closed, reducing the command pilot pressure to the tank pressure, and the lifting control valve 65 is controlled to the neutral position, thereby immediately stopping the lifting operation of the cab 50.

[0075] The processing flow from S25 to S40 also corresponds to the control to stop the raising and lowering operation of the driver's cab as described in each claim. Furthermore, the processing flow from S5 to S40 corresponds to the control to stop the raising and lowering operation of the driver's cab as described in each claim.

[0076] After S40 is complete, this flow ends, and the process returns to S5, repeating the same steps.

[0077] As described above, in S20, the nearest contact distance D is calculated between the virtual circle SC (nearest contact R) of the front attachment 106 and the reference contour line CR of the cab 50, and proximity cab stop control is performed in S40 and S50. As a result, regardless of the height position of the cab 50 (whether the cab 50 is in its highest and lowest positions, or in an intermediate position further forward than the highest and lowest positions), when the front attachment 106 is positioned within the operational restriction area 70 (see Figure 5) around the cab 50, contact with the front attachment 106 can be avoided by slowing down or stopping the raising and lowering movement of the cab 50 based on its nearest-closest-point distance D. Furthermore, regardless of the positional relationship of the front attachment 106 with respect to the reference contour line CR of the cab 50 (not only when the front attachment 106 is in front of the reference contour line CR, but also when it is above or below the reference contour line CR), when the front attachment 106 is positioned within the operational restriction area 70 around the cab 50 (see Figure 5), contact with the front attachment 106 can be avoided by slowing down or stopping the raising and lowering operation of the cab 50 based on its nearest proximity distance D.

[0078] <Examples of cab operation patterns> An example of the operation of the cab 50 when the controller 45 performs the above-mentioned priority cab stop control and proximity cab stop control is explained by the time chart in Figure 9.

[0079] In Figure 9, in this example, at time t0, the shut-off lever 43 is switched to the locked position. Furthermore, neither the lifting operation using the lifting switch 44 to raise or lower the cab 50, nor any operation of the front work equipment 103, etc. (i.e., operation of the operating lever devices 4a to 4e) is performed. As a result, the lifting speed of the cab 50 is maintained at a stopped (stationary) state of 0.

[0080] Subsequently, at time t1, the shut-off lever 43 is switched to the unlocked position, but no lifting or lowering operation is performed by the lifting switch 44. Therefore, the lifting speed of the cab 50 remains at 0, maintaining a stopped (stationary) state.

[0081] Subsequently, at time t2, the lifting switch 44 is used to perform the lifting operation. As a result, S10 is determined to be Yes, then S15 is determined to be No, and the processes of S20, S25, S30, and S50 are executed. Pilot pressure from the electromagnetic proportional control valves 67a and 67b switches the lifting control valve 65, and the supply of pressurized oil to the lifting cylinder 64 begins. As a result, the lifting speed of the cab 50 increases, reaching its maximum speed at time t3.

[0082] Here, at time t4, work operations using the front work implement 103 are initiated. As a result, after S15 is determined to be Yes, S35 is determined to be Yes, and the process of S60 is executed, which slows down the lifting and lowering movement of the cab 50. Then, at time t5, the lifting and lowering speed of the cab 50 becomes 0, and the lifting and lowering of the cab 50 stops. The period from time t4 to t6 corresponds to the aforementioned priority cab stop control.

[0083] Subsequently, at time t6, the work operation using the front work implement 103, which had started at time t4, is completed. As a result, S15 is determined to be No, and after going through S20, S25, and S30, the process of S50 is executed again, the supply of pressurized oil to the lifting cylinder 64 is started, and the lifting speed of the cab 50 increases again, reaching its maximum speed at time t7.

[0084] At this time, as a result of the cab 50 moving up and down as described above, at time t8, the front work implement 103 (for example, the front attachment 106), which has been stationary since time t6, enters the stopping area B around the cab 50. As a result, S30 is judged as Yes, and the process of S60 is executed via S35, causing the up and down movement of the cab 50 to slow down.

[0085] Subsequently, as the cab 50 continues its lifting and lowering motion while decelerating, at time t9, the front work implement 103 (for example, the front attachment 106) enters the emergency stop area A around the cab 50. As a result, S25 is judged as Yes, the process in S40 is executed, and the lifting and lowering speed of the cab 50 immediately becomes 0 (emergency stop). The period between time t8 and t9 corresponds to the aforementioned proximity cab stop control.

[0086] <Effects of the Embodiment> As described above, in this embodiment, the operator can operate the front work implement 103 by operating the operating lever devices 4a to 4e, and can raise and lower the cab 50 by operating the lifting switch 44. The controller 45 controls the operation of the front work implement 103 and the raising and lowering of the cab 50. At that time, the controller 45 also controls the stopping of the raising and lowering of the cab 50.

[0087] In other words, the controller 45 stops the raising and lowering of the cab 50 when the raising and lowering operation of the cab 50 is performed by the lifting switch 44 and the operating operation of the front work implement 103 is performed by the operating lever devices 4a to 4e (see S15 in Figure 4) (see S60). In other words, the cab 50 cannot be raised or lowered automatically while the front work implement 103 is in operation.

[0088] Furthermore, the controller 45 stops the raising and lowering operation of the cab 50 when the lifting switch 44 is used to operate the lifting and lowering operation of the cab 50, and the distance between the cab 50 and the front work equipment 103 is less than or equal to the first value D1 (in the example above, when it is within the emergency stop area A or stop area B) (see S40 and S60 in Figure 4).

[0089] As a result, the operator's operation of the lifting switch 44 prevents the cab 50 from moving up or down and interfering with the front work implement 103. In this case, there is no need to switch between operating the front work implement 103 and operating the cab 50 with a switch. In other words, without performing such a switch operation, the aforementioned interference can be prevented while selectively performing the lifting and lowering of the cab 50 and the operating of the front work implement 103, thereby improving work efficiency. As described above, this embodiment makes it possible to achieve both avoidance of interference between the front work implement 103 and the cab 50 and a reduction in the operator's labor.

[0090] Furthermore, in this embodiment, when the lifting operation is performed via the lifting switch 44 and the work operation is performed via the operating lever devices 4a to 4e, the lifting operation of the cab 50 is gradually slowed down and then stopped (see S60). When the raising and lowering of the cab 50 and the operating of the front work implement 103 are occurring simultaneously, stopping the raising and lowering of the cab 50 can prevent interference between the cab 50 and the front work implement 103. In this case, gradually slowing down the raising and lowering of the cab 50 before stopping can reduce the impact on the operator.

[0091] Furthermore, in this embodiment, when the lifting operation is performed via the lifting switch 44, and the distance D between the cab 50 and the front work implement 103 is less than or equal to the first value D1 and greater than or equal to the second value D2 (in the above example, outside the emergency stop area A and within the stop area B), the lifting operation of the cab 50 is gradually slowed down and then stopped. If the distance is less than the second value D2 (in the above example, within the emergency stop area A), the lifting operation of the cab 50 is stopped. When the distance D between the cab 50 and the front work implement 103 is approaching, stopping the raising and lowering movement of the cab 50 can prevent interference between the cab 50 and the front work implement 103. In this case, if the distance D is sufficient and greater than or equal to the second value D2, gradually slowing down the raising and lowering movement of the cab 50 and stopping it can reduce the impact on the operator (see S35). On the other hand, if the distance D is small and less than the second value D2, the raising and lowering movement can be stopped quickly by stopping it without slowing down (see S40).

[0092] In this embodiment, a shut-off lever 43 is provided on the cab 50. When the shut-off lever 43 is switched to the unlocked position, the operation of the control lever devices 4a to 4g for controlling the operation of the front work implement 103 is effective. As a result, the operator can operate the front work implement 103 and the like as intended by operating the control lever devices 4a to 4g. On the other hand, when the shut-off lever 43 is switched to the locked position, the operation of the operating lever devices 4a to 4g is disabled, and the front work implement 103, etc. will not operate even if the operating lever devices 4a to 4g are operated. When the controller 45 is in this locked position, it executes the process in S40 to stop the raising and lowering movement of the cab 50 regardless of whether the lifting switch 44 is operated or not. This prevents the cab 50 from raising and lowering on its own and interfering with the front work implement 103 when the front work implement 103, etc. is not operating.

[0093] In this embodiment, in particular, hydraulic fluid is supplied to the bottom side (or rod side; the same correspondence applies in parentheses below) of the lifting cylinder 64, and the lifting cylinder 64 is driven to extend (or retract), causing the cab 50 to move upward (or downward). The lifting control valve 65, which controls the flow of hydraulic fluid supplied to and discharged from the lifting cylinder 64, is operated by pilot pressure guided by one or the other pilot lines 66a, 66b. At this time, electromagnetic proportional control valves 67a, 67b are provided in the pilot lines 66a, 66b, respectively. Then, in S40 or S60, the controller 45 outputs command signals to the electromagnetic proportional control valves 67a and 67b to generate pilot pressure in the pilot lines 66a and 66b, thereby setting the electromagnetic proportional control valves 67a and 67b to the neutral position. As a result, the supply of hydraulic fluid to the bottom and rod sides of the lifting cylinder 64 is stopped, and the lifting operation of the cab 50 can be stopped.

[0094] Note that the procedure described above using Figure 6 is just one example, and at least some of the above procedure may be deleted or modified, or other procedures may be added. Also, the order of at least some of the above procedures may be changed, or multiple procedures may be combined into a single procedure.

[0095] <Regarding the problems to be solved and the effects of the invention> The problems that this invention aims to solve and the effects of this invention are not limited to those described above. In other words, this invention may solve problems not mentioned above, produce effects not mentioned above, solve only some of the problems described, or produce only some of the effects described. <Regarding shape, numerical values, structure, and time series> With regard to the components illustrated in the embodiments and drawings, their shapes, numerical values, or the interrelationships of the structure or time series of multiple components can be arbitrarily modified and improved within the scope of the technical concept of the present invention.

[0096] In the above, the arrows shown in Figure 3, etc., represent only one example of signal flow and do not limit the direction of signal flow.

[0097] Furthermore, the flowchart shown in Figure 6, etc., does not limit the present invention to the procedures shown in the flowchart above, and procedures may be added, deleted, or their order changed within the scope that does not depart from the spirit and technical idea of ​​the invention.

[0098] In addition to what has already been described above, the methods described in the above embodiments and their respective modifications may be used in appropriate combinations.

[0099] Furthermore, although not to be exemplified individually, the present invention may be implemented with various modifications without departing from its spirit. [Explanation of Symbols]

[0100] 4a~4g Operating lever device 31p Angle sensor (attitude detection device) 31q Angle sensor (attitude detection device) 31r Angle Sensor (Attitude Detection Device) 41. Link Angle Sensor (Position Detection Device) 43 Shut-off lever 44 Lifting switch 45 Controllers 50 Cab (driver's cab) 60 Lifting device 64. Lifting Cylinder (Lifting Hydraulic Cylinder) 65. Lifting control valve (pilot-operated control valve) 66a Pilot line (one-sided pilot conduit) 66b Pilot line (other side pilot conduit) 67a Electromagnetic proportional control valve (first electromagnetic proportional valve) 67b Electromagnetic proportional control valve (2nd electromagnetic proportional valve) 100 Lower running body 103 Front work machine 104 Boom 105 Arm 106 Front Attachment 110 Lower running body 111 Upper rotating body A Emergency stop area B Stop area D1 First value (predetermined value) D2 Second value (a predetermined threshold)

Claims

1. The car body and, A driver's cab is provided on the vehicle body so as to be able to be raised and lowered, A lifting switch for operating the raising and lowering of the driver's cab, A position detection device for detecting the position information of the driver's cab, A front work implement is mounted on the vehicle body so as to be able to move up and down, An operating lever for controlling the working motion of the front work machine, A posture detection device for detecting posture information of the front work machine, A controller that controls the lifting and lowering operation of the driver's cab and the working operation of the front work machine based on the position information detected by the position detection device and the attitude information detected by the attitude detection device, In a work machine equipped with, The aforementioned controller, When the lifting operation is being performed via the lifting switch, if the work operation is being performed via the operating lever, or if the distance between the driver's cab and the front work machine, determined based on the position information detected by the position detection device and the posture information detected by the posture detection device, is less than or equal to a predetermined value, control is performed to stop the lifting operation of the driver's cab. A type of work machine characterized by this feature.

2. In the work machine described in claim 1, The aforementioned controller, When the lifting operation is performed via the lifting switch and the work operation is performed via the operating lever, the lifting operation of the driver's cab is gradually slowed down and then stopped. A work machine characterized by the following features.

3. In the work machine described in claim 1, The aforementioned controller, When the lifting operation is performed via the lifting switch, and the distance between the driver's cab and the front work machine is less than or equal to the predetermined value, if the distance is greater than or equal to a predetermined threshold, the lifting operation of the driver's cab is gradually slowed down and then stopped; if the distance is less than the threshold, the lifting operation of the driver's cab is stopped. A work machine characterized by the following features.

4. In the work machine described in claim 1, The driver's cab is provided with a shut-off lever that can be switched between a locked position that disables the operation of the operating lever and an unlocked position that enables the operation of the operating lever. The aforementioned controller, If the shut-off lever is operated to the unlocked position, control is performed to stop the raising and lowering of the driver's cab. If the shut-off lever is operated to the locked position, control is performed to stop the raising and lowering of the driver's cab regardless of whether the raising and lowering operation is performed via the lifting switch. A work machine characterized by the following features.

5. In the work machine described in claim 1, A lifting hydraulic cylinder for which hydraulic fluid is supplied to the rod side and driven in the contraction direction to move the operator's chamber downward, and hydraulic fluid is supplied to the bottom side and driven in the extension direction to move the operator's chamber upward, A pilot-operated control valve, which is operated by pilot pressures on one side and the other side, respectively, which are guided through pilot lines on one side and the other side, and controls the flow of hydraulic fluid supplied to and discharged from the lifting hydraulic cylinder, First and second solenoid proportional valves are provided in the pilot pipelines on one side and the other side, respectively, and generate the pilot pressures on the one side and the other side, respectively, which are led to the pilot-operated control valves, based on command signals output from the controller. It further possesses, The aforementioned controller, The command signals that drive the pilot-operated control valves to generate the pilot pressures on one and the other side to set them to the neutral position are output to the first and second electromagnetic proportional valves, thereby stopping the raising and lowering operation of the operator's cab. A work machine characterized by the following features.

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