JP2020109240A - Movable cab work machine - Google Patents

Abstract

To improve work efficiency when working near a cab by moving a front attachment to a lower part of the cab, in a movable cab work machine equipped with an interference prevention device that stops a front work implement to avoid contact between the two when the front work implement approaches the cab.SOLUTION: When an interference prevention region change switch 43 is operated, a controller 45 performs interference prevention region changing processing for invalidating an interference prevention control function in a region portion of an interference prevention region 70 below a lower surface of a cab 50, and performs the interference prevention control based on an interference prevention region 70A subjected to the interference prevention region changing processing.SELECTED DRAWING: Figure 3

Description

The present invention relates to a movable cab working machine provided with a movable cab capable of moving up and down (hereinafter, simply referred to as “cab”), and particularly to a front working machine when a front attachment mounted on the front working machine approaches the cab. The present invention relates to a movable cab working machine equipped with an interference prevention device that stops the contact between the two to avoid contact between the two.

In a cab movable work machine equipped with a movable cab, when the front attachment mounted on the front work machine approaches the cab and enters the interference prevention area set around the cab, the operation of the front work machine is stopped. As a device provided with an interference prevention device for avoiding contact between the front working machine and the cab, there is one described in Patent Document 1.

Patent Document 1 "provides a detection device that detects the amount of movement of the cab (cab) with respect to the main body (lower traveling structure and upper revolving structure), and corrects the interference prevention region based on the detection result of this detection device." It has been described.

Japanese Patent No. 3310783

In the work machine of Patent Document 1, when the cab is a cab that can be moved up and down, the front work machine stops when the front attachment enters the interference prevention area and the front attachment is cab regardless of the height position of the cab. Contact with is avoided.

By the way, as work performed by the cab movable work machine, there is work in the vicinity of the cab performed by moving a front attachment (for example, a lift magnet, a fork grapple, etc.) to the lower side of the cab. In such work near the cab, the operator works while moving the front working machine at a slow speed at which inertial force does not work. However, nevertheless, when the front attachment enters the interference prevention area, the front working machine stops, so that work in the vicinity of the cab cannot be performed.

In such a case, the operator operates the operation lever for traveling to temporarily retract the work machine to a position where the front attachment does not enter the interference prevention area, and then resumes the work. For this reason, there is a problem that the work in the vicinity of the cab takes time and the work efficiency is not good.

An object of the present invention is to move a front attachment downward in a cab in a cab movable work machine equipped with an interference prevention device that stops the front work machine when the front work machine approaches the cab to avoid contact between the two. It is an object of the present invention to provide a cab movable work machine capable of improving work efficiency when performing work near the cab.

In order to solve such a problem, the present invention provides a vehicle body provided with a cab capable of ascending and descending, a front working machine connected to the vehicle body so as to be vertically rotatable, and equipped with a front attachment, and the front attachment. When approaching the cab and entering an interference prevention area set around the cab, the operation of the front working machine is stopped to perform interference prevention control to avoid contact between the front working machine and the cab. In a cab movable work machine including an interference prevention device, the interference prevention device includes an attitude sensor that detects a state quantity related to a position and an attitude of the front work machine, and a height sensor that detects a height position of the cab. An interference prevention area change switch, a controller that calculates a distance between the front attachment and the cab based on detection values of the posture sensor and the height sensor, and performs the interference prevention control based on the distance. The controller, when the interference prevention area changing switch is operated, performs an interference prevention area changing process for invalidating the interference prevention control function in an area portion of the interference prevention area lower than the lower surface of the cab. The interference prevention control is performed based on the interference prevention area that has been subjected to the interference prevention area changing process.

When the interference prevention area change switch is operated in this way, and when the interference prevention area change switch is operated, the interference prevention area change process is performed to perform work near the cab, such as moving a work target under the cab. In addition, the front attachment can be moved to the lower side of the cab without retreating the work machine, and the work under the cab can be performed, so that the work efficiency can be improved.

According to the present invention, when performing work in the vicinity of the cab such as movement of a work object under the cab, the front attachment is moved to the lower side of the cab without retracting the work machine, and work on the lower side of the cab is performed. It becomes possible to improve work efficiency.

It is a figure which shows the cab movable work machine in the 1st Embodiment of this invention. It is a figure which shows the state which raised the cab (upper side) and the state which dropped it (lower side) by contrast. It is a figure which shows the hydraulic system mounted in the hydraulic excavator in the 1st Embodiment of this invention, and its control system. It is a figure which shows an example of the arrangement|positioning location of an interference prevention control cancellation switch, an interference prevention area|region change switch, and a raising/lowering switch in a driver's cab. It is a figure which shows the interference prevention area|region which performed the interference prevention area|region change process by the 2nd function of a controller, and made the interference prevention control function in the area part lower than the lower surface of the cab of an interference prevention area invalid. Similarly, it is a figure which shows the state which raised the cab (upper side) and the state which dropped it (lower side) for comparison. It is a flowchart which shows the processing function of a controller. It is a figure which expands and shows the part of the front attachment of a front working machine with a cab. It is a figure which shows the calculation table of the interference prevention control previously stored in the memory (for example, ROM) of a controller. 7 is a flowchart showing details of the process of step S140 shown in FIG. 6. It is a flowchart which shows the processing function of the controller of the cab movable hydraulic excavator in the 2nd Embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
~Constitution~
FIG. 1 is a diagram showing a cab movable working machine according to a first embodiment of the present invention. In the present embodiment, the work machine is a hydraulic excavator that is a typical example of construction machines.

1, a movable cab hydraulic excavator includes a vehicle body 100 having a movable cab (hereinafter simply referred to as “cab”) 50 that can be raised and lowered, and a front body that is connected to the vehicle body 100 so as to be vertically rotatable and has a front attachment 106 attached thereto. The work machine 103 is provided. The vehicle body 100 includes a lower traveling body 110 and an upper revolving body 111 mounted on the lower traveling body 110 so as to be capable of turning.

The front working machine 103 includes a boom 104 that is attached to the upper swing body 111 so as to be rotatable in the vertical direction, and an arm 105 that is attached to the tip of the boom 104 so as to be rotatable in the vertical/front-rear directions. The arm 106 is attached to the tip of the arm 105 so as to be rotatable in the up/down direction and the front/rear direction. The boom 104 is driven by the boom cylinder 3a, the arm 105 is driven by the arm cylinder 3b, and the front attachment 106 is driven by the attachment cylinder 3c.

The upper swing body 111 is driven by the swing motor 3e (see FIG. 3) and swings on the lower traveling body 110. The lower traveling body 110 has a pair of right and left crawlers 110a and 110b (only one side is shown in FIG. 1), and the crawlers 110a and 110b are driven by traveling motors 3f and 3g (only one side is shown) to travel.

The cab 50 is attached to a front side position on the basic frame (swing frame) 111 a of the upper swing body 111 so as to be able to move up and down with respect to the upper swing body 111 by the lifting device 60. The lifting device 60 is disposed between the upper swing body 111 and the cab 50.

The lifting device 60 includes a tower-shaped support frame 61 erected on a base frame 111a of an upper swing body 111 (vehicle body), an L-shaped mount 62 integrally attached to a lower portion of the cab 50, and a tower-shaped support frame. Of the parallel link mechanism 63 and the parallel link mechanism 63 which are rotatably connected to the upper end portion 61a of the support frame 61 and the rear stay 62a of the pedestal 62 by pins and configured to keep the cab 50 horizontal. It has a lift cylinder 64 that is rotatably connected to the upper end of the support frame 61 and a rear stay 62a of the pedestal 62 on the lower side by a pin and moves the cab 50 in the vertical direction.

The tower-shaped support frame 61 and the elevating cylinder 64 are respectively configured as a left and right pair, and the parallel link mechanism 63 is provided between the left-right pair of the tower-shaped support frame 61 and the upper end portion of the support frame 61 and the rear stay 62a of the pedestal 62. Is linked to.

In the present embodiment, the front attachment 106 is a lifting magnet that adsorbs iron scrap by the magnetic force of an electromagnet, conveys it to a truck bed or the like, and loads it. The front attachment 106 may be a fork grapple, a dismantling fork, or the like, which is an openable work tool.

FIG. 2 is a diagram showing a state in which the cab 50 is raised (upper side) and a state in which the cab 50 is lowered (lower side) in comparison. When the cab 50 is lowered as shown in the lower side of FIG. 2, the hydraulic excavator equipped with the cab 50 can perform work on the ground surface such as excavation work, like a general hydraulic excavator. it can. On the other hand, as shown in the upper side of FIG. 2, when the cab 50 is raised by the elevating cylinder 64, the operator's eyes can be raised, and even if a container such as a trunk or a container is large, a wide field of view is provided. You can work while looking inside.

FIG. 3 is a diagram showing a hydraulic system mounted on a hydraulic excavator and a control system therefor according to the first embodiment of the present invention.

First, the hydraulic system will be described.

Referring to FIG. 3, the hydraulic system of the hydraulic excavator according to the present embodiment includes a hydraulic pump 2 as a main pump, and the above-described boom cylinder 3a, arm cylinder 3b, and attachment cylinder 3c driven by the pressure oil from the hydraulic pump 2. , A plurality of actuators including a swing motor 3e and left and right traveling motors 3f and 3g, operation lever devices 4a to 4g provided corresponding to the respective hydraulic actuators 3a to 3g, a hydraulic pump 2, and a plurality of hydraulic actuators. 3a to 3g, which are switched from the neutral position by the command pilot pressure of the operation lever devices 4a to 4g, and which control the flow direction and flow rate of the pressure oil (driving direction and driving speed of the hydraulic actuators 3a to 3g). It has flow rate control valves 5a-5g and a main relief valve 6 as a safety valve.

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

Further, in the present embodiment, the hydraulic system is connected between the lifting cylinder 64 of the lifting device 60 described above and between the hydraulic pump 2 and the plurality of lifting cylinders 64, and the pilot line 66a is operated according to the operation of the lifting switch 44 (described later). , 66b, which is switched from the neutral position by the control pilot pressure to control the flow direction and flow rate of the pressure oil (driving direction and driving speed of the raising and lowering cylinder 64).

Next, the control system will be described.

The control system is provided at each rotation fulcrum of the boom 104, the arm 105, and the front attachment 106, and angle sensors 31a, 31b, which detect respective rotation angles as state quantities related to the position and orientation of the front work machine 103, are provided. 31c (posture sensor) and the tower-shaped support frame 61 are coaxially attached to the rotation fulcrum of the parallel link mechanism 63, and the rotation angle of the parallel link mechanism 63 is detected as a state quantity related to the height of the cab 50. The link angle sensor 41 (height sensor), the interference prevention control release switch 42, the interference prevention area change switch 43, the elevating switch 44, the sensor signals of the angle sensors 31a, 31b, 31c and the link angle sensor 41 interfere with each other. The controller 45 that inputs the switch control release switch 42, the interference prevention area change switch 43, and the lifting/lowering switch 44 and performs arithmetic processing for interference prevention control, the discharge oil passage 7a of the pilot pump 7, and the pilot pressure supply. An electromagnetic switching type hydraulic lock valve 34 arranged between the oil passage 7b and the electromagnetic proportional pressure reducing valves 33a, 33b provided on the pilot lines 10a, 11a, 12a and driven by an electric signal output from the controller 45. , 33c, and pilot lines 66a, 66b branched from the pilot pressure supply oil passage 7b, and electromagnetic proportional control valves 67a, 67b driven by electric signals output from the controller 45, a monitor 46, and a warning buzzer 47. It has and.

The interference prevention control release switch 42, the interference prevention area changing switch 43, the elevating switch 44, the monitor 46, and the warning buzzer 47 are installed inside the cab 50 in the cab.

The interference prevention control cancellation switch 42 is a switch that cancels the interference prevention control when pressed by the operator, and is, for example, a momentary-type/automatic recovery switch that is turned on while being pressed. The interference prevention control release switch 42 is used when the hydraulic excavator is placed in the transportation posture, or when performing special work with low frequency such as when the hardware breaks down or is damaged.

The interference prevention area changing switch 43 is a switch relating to the feature of the present invention, and when pushed by an operator, the interference prevention control function is disabled in the area portion of the interference prevention area 70 below the lower surface of the cab 50. The switch is for setting the interference prevention area 70A that enables the work in the vicinity of the cab 50 that has been subjected to the prevention area change processing and that has been subjected to the interference prevention area change processing. The interference prevention area change switch 43 is also a momentary type/automatic return switch that is turned on while being pressed. Here, the lower surface of the cab 50 is the lower surface of the L-shaped mount 62 integrally attached to the lower portion of the cab 50 described above.

The elevating switch 44 is a switch for instructing an elevating operation of the cab 50, and includes a raising direction instruction switch 44a and a lowering direction instruction switch 44b. These instruction switches 44a and 44b are also momentary type/automatic return switches that are turned on only while they are being pressed.

FIG. 4 is a diagram showing an example of arrangement locations of the interference prevention control release switch 42, the interference prevention area changing switch 43, and the elevating switch 44 in the cab.

A left control box 71 having a left control lever (operation lever) LC used as an operation lever of the above-described arm and turning operation lever devices 4b and 4e is arranged at the left front part of the driver's seat in the cab. The console box 72 is arranged on the rear side and the right side. Various switches are provided on the top panel 73 of the console box 72, and the interference prevention control release switch 42 and the elevating switch 44 (the raising direction instruction switch 44a and the lowering direction instruction switch 44b) are provided at positions near the rear operator of the top panel 73. ) Has been placed. Further, three switches are provided on the grip top of the left control lever LC, and the interference prevention area changing switch 43 is assigned to one of them.

The electromagnetic proportional pressure reducing valves 33a, 33b, 33c reduce the command pilot pressure generated by the operating lever devices 4a, 4b, 4d according to the electric signal from the controller 45, and the reduced command pilot pressure is used as the pilot line 10a. , 11a, 13b to the pressure receiving portions 20a, 21a, 22a of the flow rate control valves 5a, 5b, 5c.

The electromagnetic proportional control valves 67a and 67b generate a control pilot pressure (secondary pressure) according to an electric signal from the controller 45 based on the hydraulic pressure (primary pressure) generated by the pilot pump 7, and the control pilot pressure is generated. Are guided to the pressure receiving portions 65a and 65b of the elevation control valve 65 via the pilot lines 66a and 66b.
To do.

When the front attachment 106 approaches the cab 50 and enters the interference prevention area 70 set around the cab 50, the above-described control system stops the operation of the front work machine 103 and the front work machine 103 and the cab 50. An interference prevention device is configured to perform interference prevention control for avoiding contact with.

The controller 45 has the following functions.

First, the controller 45 firstly, based on the detection values of the angle sensors 31a, 31b, 31c (posture sensor) and the link angle sensor 41 (height sensor), the distance between the front attachment 106 and the cab 50 (described later). The distance D) is calculated, and the interference prevention control is performed based on this distance.

Second, when the interference prevention area change switch 43 is operated (pressed), the controller 45 disables the interference prevention control function in the area portion of the interference prevention area 70 below the lower surface of the cab 50. The interference prevention area changing process is performed, and the interference prevention control is performed based on the interference prevention area 70A on which the interference prevention area 70 changing process is performed.

As shown in FIG. 1, the interference prevention area 70 during the normal work in which the interference prevention area change switch 43 is not pressed is set on the front side, the upper side, and the lower side of the cab 50. Further, the interference prevention area 70 has a deceleration area A and a stop area B, and is located in the order of the deceleration area A and the stop area B from the outside toward the inside of the cab 50. When the front attachment 106 enters the deceleration area A, the controller 45 drives the electromagnetic proportional pressure reducing valves 33a, 33b, 33c to reduce the command pilot pressure, and the front working machine 103 (boom 104, arm 105, and front attachment 106). Decelerate the operation. When the front attachment 106 enters the stop area B, the controller 45 fully closes the electromagnetic proportional pressure reducing valves 33a, 33b, 33c, and stops the operation of the front working machine 103 (the boom 104, the arm 105, and the front attachment 106).

Although not shown, a prohibited area is set further inside the stop area B, and when the front working machine 102 enters the prohibited area, the controller 45 switches the hydraulic lock valve 34 and the pilot pump 7 is operated. The communication between the discharge oil passage 7a and the pilot pressure supply oil passage 7b is cut off to make the hydraulic system inoperable, and the entire operation of the hydraulic excavator is stopped.

FIG. 5 shows the interference prevention area 70A in which the interference prevention area changing process is performed by the second function of the controller 45, and the interference prevention control function is disabled in the area portion of the interference prevention area 70 below the lower surface of the cab 50. FIG. 3 is a diagram showing, similarly to FIG. 2, a state in which the cab 50 is raised (upper side) and a state in which it is lowered (lower side) for comparison.

The interference prevention area 70 shown in FIG. 1 is set on the front side, the upper side, and the lower side of the cab 50 as described above. However, when the interference prevention area change switch 43 is pressed, the cab of the interference prevention area 70 is in the meantime. The interference prevention control function in the area lower than the lower surface of 50 is disabled, and the interference prevention area 70A in which the area lower than the lower surface of the cab 50 of the interference prevention area 70 in the normal operation shown in FIG. 1 is cut off. Is changed to. This allows the operator to easily perform work in the vicinity of the cab 50 (hereinafter appropriately referred to as work in the vicinity of the cab).

In addition, when the interference prevention area change switch 43 is pressed, the interference prevention control function of all the area lower than the lower surface of the cab 50 of the interference prevention area 70 is not invalidated, but from the lower surface of the cab 50, An area (for example, stop area B) in which the interference prevention control is performed may be left for a predetermined distance such that the front attachment 106 does not contact the lower surface due to inertia. As a result, when working near the cab, it is possible to reliably prevent the front attachment 106 from hitting the lower surface of the cab 50, and to work safely.

~control~
FIG. 6 is a flowchart showing the processing function of the controller 45.

The controller 45 first determines whether or not the interference prevention control release switch 42 is pressed (step S100). When the interference prevention control release switch 42 is pressed, the monitor 46 pushes the interference prevention control release switch 42. Is displayed (interference prevention control is released) (for example, a message is displayed) to allow the operator to visually confirm that the interference prevention control release switch 42 is pressed, and a warning is issued. The buzzer 47 is activated to generate a warning sound so that the operator can hear it.

When the interference prevention control release switch 42 is not pressed, the controller 45 inputs the sensor signals from the angle sensors 31a, 31b, 31c and the link angle sensor 41 (step S105). Next, the controller 45 determines the height of the cab 50 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 and the cab 50 stored in advance in a memory (for example, ROM). Calculate (step S110). As the height of the cab 50, for example, it is preferable to calculate the height of the lower surface of the cab 50.

In addition, the controller 45 uses the rotation angles of the boom 104, the arm 105b, and the front attachment 106 detected by the angle sensors 31a, 31b, and 31c, and the dimensions of each front member stored in the memory (for example, ROM) in advance to detect the front position. The position of the attachment 106, more specifically, the position of the representative point of the front attachment 106 is calculated (step S115).

FIG. 7 is a diagram showing an example of representative points by enlarging the portion of the front attachment 106 of the front working machine 103 together with the cab 50.

In FIG. 7, the lifting magnet that is the front attachment 106 includes a bracket 106a, and the bracket 106a is rotatably pin-connected to the tip of the arm 105 by a pin 106b. The pin 106b serves as a pivot of the lifting magnet. Further, one end of the attachment link 106c is rotatably pin-coupled to the bracket 106a by a pin 106d, one end of the arm link 105a is rotatably pin-coupled to the arm 105, and the piston rod of the arm cylinder 3c is attached to the attachment link 106c. Is pivotally connected to the other end of the arm link 105a and the other end of the arm link 105a. The angle of rotation of the front attachment 106 with respect to the arm 105 is detected by the angle sensor 31c.

The representative point of the front attachment 106 is, for example, in the cab 50 of the envelope circle SC that includes the rotation fulcrum (pin 106b) of the front attachment 106 at the tip of the arm 105 as a part of an arc and encloses the entire front attachment 106. It is preferable to set it to the closest point (closest contact point) R. The position of this closest contact point R is, when the front attachment 106 is operated toward the cab 50, the detected value of the angle sensor 31c, the height of the cab 50 calculated as described above, and a memory (for example, ROM) in advance. From the dimensions of the front attachment 106 including the cab 50 and the bracket 106a stored in FIG. 5, the position closest to the cab 50 on the envelope circle SC of the front attachment 106, that is, between the envelope circle SC of the front attachment 106 and the cab 50. It can be calculated as a position on the envelope circle SC where the distance D is smallest.

The representative point may be set on another virtual circle instead of the envelope circle SC. As another virtual circle, for example, a virtual circle passing through the pin 106b, which is the fulcrum of rotation of the bracket 106a, and the other pin 106d can be cited.

Further, the position of the closest contact point R of the front attachment 106 can be calculated as a coordinate value of an XY coordinate system whose origin is a pivotal fulcrum of a base end portion of the boom 104, for example, an appropriate position of the upper swing body 111. The X axis of the XY coordinate system is a coordinate axis in the horizontal direction (direction parallel to the main surface of the basic frame of the upper swing body 111), and the Y axis is vertical (vertical to the main surface of the basic frame of the upper swing body 111). Direction). In this case, in step S110, 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.

Next, the controller 45 determines whether or not the interference prevention area change switch 43 is pressed (step S120), and when the interference prevention area change switch 43 is not pressed, sets the interference prevention area 70 for normal work. (Step S125).

On the other hand, when the interference prevention area change switch 43 is pressed, the controller 45 indicates that the monitor 46 is pressing the interference prevention area change switch 43 (the interference prevention area 70 is changed to the interference prevention area 70A). A notification (for example, a message) is displayed so that the operator can visually confirm that the interference prevention area change switch 43 is pressed, and the warning buzzer 47 is activated to press the interference prevention area change switch 43. A warning sound that indicates that the interference prevention area 70 has been changed to the interference prevention area 70A is generated so that the operator can visually check it (step S130). In addition, when the interference prevention area change switch 43 is pressed, the controller 45 distinguishes between the display of the monitor 46 and the warning sound of the warning buzzer 47 when the interference prevention control release switch 42 is pressed. Displays in a different manner and generates a warning sound.

Further, when the interference prevention area change switch 43 is pressed, the controller 45 stores the history of the operation in the memory so that it can be confirmed later that the interference prevention area change switch 43 is pressed (step S135). ).

Next, the controller 45 sets the interference prevention area 70A for work near the cab (step S140).

The setting of the interference prevention area 70 in the normal work in step S125 and the setting of the interference prevention area 70A in the work near the cab in step S140 are performed as follows, for example.

FIG. 8 is a diagram showing an interference prevention control calculation table stored in advance in the memory (eg, ROM) of the controller 45.

In FIG. 8, the horizontal axis represents the above-described distance D between the front attachment 106 and the cab 50, and the vertical axis represents the front-rear pressure ratio Rp of the electromagnetic proportional pressure reducing valves 33a, 33b, 33c. The distance D between the front attachment 106 and the cab 50 is the distance (closest distance) between the closest point R of the envelope circle SC of the front attachment 106 and the cab 50, as described above.

In the calculation table of FIG. 8, the relationship between the distance D and the front-rear pressure ratio Rp is that the front-rear pressure ratio Rp is 100% when the distance D is equal to or larger than the first threshold value D1, and the pressure when the distance D becomes smaller than the first threshold value D1. The ratio Rp gradually decreases from 100%, and is set to 0% when the distance D reaches the second threshold D2. The first threshold value D1 corresponds to the boundary position between the non-interference prevention area and the deceleration area A of the interference prevention area 70 or 70A, and the second threshold value D2 corresponds to the boundary position between the deceleration area A and the stop area B. The third threshold D3 is on the side smaller than the second threshold D2 (the side closer to the origin). The third threshold value D3 corresponds to the boundary position between the stop area B and the prohibited area (not shown).

In step S125, the controller 45 sets the interference prevention area 70 in the normal operation as shown in FIGS. 1 and 2 by reading the calculation table of FIG. 8 from the memory and making it available for calculation.

Further, in step S140, the controller 45 sets the interference prevention area 70A in the work near the cab by executing the processing of the flowchart shown in FIG.

In FIG. 9, the controller 45 compares the height of the lower surface of the cab 50 calculated in step S110 with the position of the closest contact point R of the front attachment 106 calculated in step S115, and the closest contact point of the front attachment 106 is the lower surface of the cab 50. It is determined whether it is lower than (step S140a). In this determination, the Y coordinate value Ya of the closest contact point R of the front attachment 106 and the Y coordinate value Yb of the height of the lower surface of the cab 50 are compared to determine whether “absolute value of Ya”>“absolute value of Yb”. It does by judging.

Next, when the controller 45 determines that the closest contact R of the front attachment 106 is not lower than the lower surface of the cab 50, that is, when it is determined that “absolute value of Ya”≦“absolute value of Yb”, The calculation table of FIG. 8 is read from the memory so that it can be used for calculation (step S140b). On the other hand, if it is determined that the closest contact point R of the front attachment 106 is lower than the lower surface of the cab 50, that is, if it is determined that “absolute value of Ya”>“absolute value of Yb”, the following operation is performed. The process proceeds to step (step S145).

As described above, only when the closest contact point R of the front attachment 106 is higher than the lower surface of the cab 50 (“absolute value of Ya”≦“absolute value of Yb”), the operation table of FIG. The interference prevention region changing process for invalidating the interference prevention control function in the region portion of the interference preventing region 70 below the lower surface of the cab 50 is performed, and the interference preventing region 70 changing process is performed. The interference prevention control can be performed based on the performed interference prevention area 70A.

Next, if the controller 45 reads the calculation table of FIG. 8 in steps S125 and S140b, it determines whether the closest contact R of the front attachment 106 is outside the interference prevention area 70 or 70A, within the deceleration area, or within the stop area. The determination is made (step S145). In this determination, the distance D between the closest contact R of the front attachment 106 and the cab 50 is calculated, and if the distance D is larger than the first threshold D1 (D>D1), the distance D is less than or equal to the first threshold D1. This can be performed by determining whether the value is larger than the second threshold value D2 (D2<D≦D1) or whether the distance D is equal to or less than the second threshold value D2 (D≦D2). The distance D is calculated from the height of the cab 50 calculated in step S110, the position of the closest contact R of the front attachment 106 calculated in step S115, and the size of the cab 50 stored in a memory (for example, ROM) in advance. be able to.

When the controller 45 determines that the closest contact R of the front attachment 106 is outside the interference prevention area 70 or 70A, the controller 45 does nothing and returns to the start and repeats the control cycle.

When the controller 45 also determines in step S140a that the closest contact R of the front attachment 106 is lower than the lower surface of the cab 50, the controller 45 does nothing and returns to the start and repeats the control cycle.

On the other hand, when the controller 45 determines that the closest contact R of the front attachment 106 is within the deceleration area A, the controller 45 refers to the distance D calculated as described above in the calculation table of FIG. 8 to calculate the front-rear pressure ratio Rp. Then, the control current corresponding to the front-rear pressure ratio Rp is output as an electric signal to the electromagnetic proportional pressure reducing valves 33a, 33b, 33c (step S150). As a result, the electromagnetic proportional pressure reducing valves 33a, 33b, 33c reduce the command pilot pressure and gradually reduce the operation speed of the front member of the front working machine 103, thereby gradually decelerating the operation of the front working machine 103.

Further, when the controller 45 determines that the closest contact R of the front attachment 106 is in the stop region B, it calculates 0% as the front-rear pressure ratio, and the control current corresponding to the front-rear pressure ratio 0% is used as an electric signal. Output to the electromagnetic proportional pressure reducing valves 33a, 33b, 33c (step S155). As a result, the electromagnetic proportional pressure reducing valves 33a, 33b, 33c are fully closed to reduce the command pilot pressure to the tank pressure, and the operation of the front working machine 103 is stopped.

Further, in the present embodiment, as the distance D, by calculating the distance (closest distance) between the closest point R of the envelope circle SC of the front attachment 106 and the cab 50, the front attachment 106 with respect to the cab 50 can be calculated. Even when there is a positional relationship (not only when the front attachment 106 is on the front side of the cab 50, but also on the upper side of the cab 50 or on the upper side of the cab 50 (in the case of the interference prevention area 70)). When the front attachment 106 enters the interference prevention area 70 (see FIG. 1), the interference prevention control that avoids the contact between the front attachment 106 and the cab 50 can be performed.

~effect~
According to the present embodiment configured as described above, the following effects can be obtained.

1. When carrying out work in the vicinity of the cab, such as when loading a work object such as scrap under the cab on the bed of the truck, the operator presses the interference prevention region change switch 43 to change the interference prevention region 70 to the interference prevention region 70A. As a result, the front attachment 106 can be moved to the lower side of the cab 50 without moving the hydraulic excavator backward, and the work under the cab can be performed, so that the work efficiency can be improved.

2. When performing work in the vicinity of the cab, the operator intentionally interferes by pushing the interference prevention control release switch 42, which is used when the hydraulic shovel is placed in the transportation posture or when the hardware breaks down or is damaged, with one finger. In some cases, the prevention control function is released, and the operation lever is operated by the other hand to move the front work implement 103 below the cab to perform work. However, in this case, not only the operation is performed with one hand, but also the function of the interference prevention control is lost, so that not only the work efficiency is lowered, but also an operation error may occur. On the other hand, in the present embodiment, by pressing the interference prevention area changing switch 43 to change the interference prevention area 70A, the operator can operate the operation lever with both hands, improving operability and improving work efficiency. Can be improved.

3. When the interference prevention area changing switch 43 is operated, a display (for example, a message display) indicating that the interference prevention area changing switch 43 is operated is displayed on the monitor 46, and the warning buzzer 47 is operated to cause the interference prevention area changing switch. A warning sound is generated to inform that 43 has been operated. This allows the operator to visually and audibly confirm that the interference prevention area 70 has been changed to the interference prevention area 70A.

4. Further, when the interference prevention area change switch 43 is operated, the display on the monitor 46 when the interference prevention control release switch 42 is operated and the warning sound from the warning buzzer 47 are distinguished from each other, and the display is displayed in a different mode from that. However, since the warning sound is generated, it is necessary to accurately grasp that the interference prevention area change switch 43 is being operated without the interference prevention control release switch being confused with the display and warning sound by the operation of 42. You can

5. When the interference prevention area change switch 43 is operated, the history of the operation is stored in the memory. As a result, when the front attachment 106 hits the lower surface of the cab 50 due to a malfunction of the interference prevention control, or when the interference prevention area change switch 43 is operated to set the interference prevention area 70A in the vicinity work, When the front attachment 106 hits the lower surface of the cab 50, the operator or maintenance staff can confirm which is the cause by looking at the operation history.

<Second Embodiment>
FIG. 10 is a flowchart showing the processing function of the controller 45 of the cab movable hydraulic excavator according to the second embodiment of the present invention.

In the first embodiment, the interference prevention area 70 can be changed to the interference prevention area 70A regardless of the height of the cab 50. In this case, when the lower surface of the cab 50 is close to the ground and the distance between the ground and the lower surface of the cab 50 is narrow, when the front attachment 106 is operated in the vicinity of the cab, the front attachment 106 is positioned on the lower surface of the cab 50. May come into contact.

In the present embodiment, in order to avoid such a situation, it is possible to change to the interference prevention area 70A only when the height of the cab 50 is equal to or higher than a predetermined threshold value.

That is, in FIG. 10, after calculating the position of the front attachment 106 in step S115, it is determined whether or not the height of the cab 50 calculated based on the detection value of the link angle sensor 41 in step S110 is equal to or greater than a predetermined threshold value. If it is determined (step S200) and the height of the cab 50 is equal to or greater than a predetermined threshold value, the process proceeds to step S120 to determine whether the interference prevention area change switch 43 is pressed, and the height of the cab 50 is determined in advance. When it is lower than the predetermined threshold value, step S120 is skipped and the process proceeds to step S125 where the interference prevention area 70A in the cab vicinity work is set. The threshold value is set in advance as a value of height at which a work space below the cab 50 can be secured.

As a result, the controller 45 causes the interference in the area below the lower surface of the cab 50 in the interference prevention area 70 when the interference prevention area change switch 43 is pressed only when the height of the cab 50 is equal to or greater than the threshold value. The interference prevention area changing process for invalidating the prevention control function is performed. Therefore, when the height of the cab 50 is lower than the threshold value, the interference prevention control by the normal interference prevention area 70 is performed, and when the front attachment 106 is operated near the cab, the front attachment 106 contacts the lower surface of the cab 50. You can reduce the possibility of working and work safely.

3a-3g Hydraulic actuators 4a-4g Operating lever devices 31a, 31b, 31c Angle sensor (posture sensor)
33a, 33b, 33c Electromagnetic proportional pressure reducing valve 41 Link angle sensor (height sensor)
42 Interference prevention control release switch 43 Interference prevention area change switch 44 Elevating switch 45 Controller 46 Monitor 47 Warning buzzer 50 Cab 60 Elevating device 63 Parallel link mechanism 64 Elevating cylinder 65 Elevating control valves 67a, 67b Electromagnetic proportional control valve 70 In normal operation Interference prevention area 70A Interference prevention area near cab 100 Vehicle body 103 Front working machine 104 Boom 105 Arm 106 Front attachment (lifting magnet)
110 Lower traveling body 111 Upper rotating body

Claims (5)

A vehicle body with a cab that can be raised and lowered,
A front working machine that is rotatably connected to the vehicle body in the vertical direction and has a front attachment attached;
Interference for stopping the operation of the front working machine and avoiding contact between the front working machine and the cab when the front attachment approaches the cab and enters an interference prevention area set around the cab. In a cab movable work machine equipped with an interference prevention device that performs prevention control,
The interference prevention device,
An attitude sensor that detects a state quantity related to the position and attitude of the front working machine,
A height sensor for detecting the height position of the cab,
Interference prevention area change switch,
A controller that calculates a distance between the front attachment and the cab based on detection values of the attitude sensor and the height sensor, and performs the interference prevention control based on the distance.
When the interference prevention area changing switch is operated, the controller performs interference prevention area changing processing for invalidating the interference prevention control function in an area portion of the interference prevention area lower than the lower surface of the cab, A movable cab working machine, characterized in that the interference prevention control is performed based on the interference prevention area that has been subjected to the interference prevention area changing process. The cab movable work machine according to claim 1,
The controller determines whether the height of the cab is greater than or equal to a predetermined threshold value based on the detection value of the height sensor, and only when the height of the cab is greater than or equal to the threshold value, the interference A movable cab working machine, which performs the interference prevention area changing process when a prevention area changing switch is operated. The cab movable work machine according to claim 1,
Further equipped with a monitor and a warning buzzer,
When the interference prevention area change switch is operated, the controller displays on the monitor that the interference prevention area change switch has been operated, and activates the warning buzzer to cause the interference prevention area change switch. A movable cab working machine characterized by generating a warning sound that informs that the operator has operated. The movable cab working machine according to claim 3,
Further comprising an interference prevention control release switch for releasing the interference prevention control,
When the interference prevention control release switch is operated, the controller displays on the monitor that the interference prevention control release switch has been operated, and activates the warning buzzer to cause the interference prevention control release switch. Generates a warning sound to inform you that
The controller is different from that at the time when the interference prevention area changing switch is operated so that it can be distinguished from the display of the monitor and the warning sound of the warning buzzer when the interference prevention control release switch is operated. A movable cab working machine characterized in that the warning sound is generated by displaying on the monitor in a form. The cab movable work machine according to claim 1,
When the interference prevention area change switch is operated, the controller stores a history of the operation in a memory so that it can be confirmed later that the interference prevention area change switch is operated. Cab movable work machine.

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