JP2020105748A - Cab movable work machine - Google Patents

Abstract

To improve work efficiency by allowing a cab to move up and down without stopping a front work implement and the cab within an interference prevention area when raising and lowering the cab, in a cab movable work machine equipped with an interference prevention device that limits an operation of the front work implement to avoid contact between the two when the front work implement approaches the cab.SOLUTION: A controller 45 calculates a distance between a front attachment 106 and a cab 50 based on detection values of attitude sensors 31a to 31c and a height sensor 41 when a lift switch 44 is operated, if this distance is larger than a predetermined distance Xo, a lifting device 60 is driven, if the distance between the front attachment and the cab is equal to or smaller than the predetermined distance Xo, before the lifting device is driven, a front work implement is operated so that the front attachment is separated from the cab, and the second interference prevention control for avoiding contact between the front work implement and the cab is performed.SELECTED DRAWING: Figure 3

Description

The present invention relates to a cab movable working machine equipped with a movable cab (hereinafter appropriately referred to simply as “cab”) that can be moved up and down, which is often used in industrial waste specification machines, and more particularly to a front attachment mounted on a front working machine. The present invention relates to a cab movable work machine including an interference prevention device that restricts the operation of the front working machine to avoid contact between the two when approaching the cab.

In a cab movable work machine equipped with a movable cab that can be raised and lowered, when the front attachment mounted on the front work machine approaches the cab and enters the interference prevention area set on the front side of the cab, the operation of the front work machine is prevented. Patent Document 1 discloses a device provided with an interference prevention device that restricts and prevents contact between the front working machine and the cab.

Patent Document 1 discloses, as a restriction area (interference prevention area) for interference prevention control,
(A) First restriction area when the cab is at the lowest position and the highest position (b) Two kinds of restriction areas: the second restriction area when the cab is at an intermediate position other than the lowest position and the highest position Is set on the front side of the cab, and the second restriction region (b) is set with reference to the position where the cab comes out most forward when the cab is moved up and down.

Further, in Patent Document 1, when the work attachment (front attachment) enters the second restricted area set on the front side of the cab when the cab is moved up and down, contact between the work attachment and the cab is avoided, so that the front work machine is provided. Interference prevention control that restricts both the operation of and the raising and lowering of the cab is performed.

Japanese Patent No. 3898111

As described above, Patent Document 1 is configured to perform interference prevention control that restricts both the operation of the front working machine and the raising and lowering of the cab when the work attachment enters the second restriction region (b). The operation of the front work implement and the lifting and lowering of the cab are limited by stopping the work attachment and the cab. Therefore, when the work attachment enters the second restricted area when the cab is moved up and down, the work attachment and the cab are forcibly stopped, and the operation is forced to be interrupted. Further, in order to restart the raising and lowering of the cab, it is necessary to move the work attachment out of the interference prevention area and then restart the work attachment, which lowers the work efficiency.

It is an object of the present invention to prevent interference when a cab is moved up and down in a cab movable work machine equipped with an interference prevention device that limits the operation of the front work machine to avoid contact between the two when the front work machine approaches the cab. It is an object of the present invention to provide a cab movable work machine capable of raising and lowering the cab without stopping the front work machine and the cab in the area and improving work efficiency.

In order to solve such a problem, the present invention relates to a vehicle body provided with a cab capable of moving up and down, and to the vehicle body so as to be rotatable in the vertical direction and to be rotatable in the vertical direction and the front-back direction. A front working machine having a plurality of front members including a front attachment; a plurality of hydraulic cylinders that drive the plurality of front members; a lifting device that lifts and lowers the cab with respect to the vehicle body; When the front attachment enters the interference prevention area set around the cab, the first interference prevention control is performed to limit the operation of the front working machine to avoid contact between the front attachment and the cab. In a cab movable work machine provided with an interference prevention device for performing, an up-and-down switch for instructing up and down of the cab, an attitude sensor for detecting a state quantity relating to the position and attitude of the front work machine, and a height position of the cab. A height sensor that detects the height of the cab, a cab lifting control device that controls the operation of the front working machine when the cab is lifted, based on the switch signals of the lifting switch and the detection values of the attitude sensor and the height sensor. The cab raising/lowering control device calculates a distance between the front attachment and the cab based on detection values of the posture sensor and the height sensor when the raising/lowering switch is operated. When the distance between the front attachment and the cab is less than the predetermined distance, the front attachment is separated from the cab before driving the lifting device when the distance between the front attachment and the cab is less than the predetermined distance. It is assumed that the front work machine is operated to perform the second interference prevention control for avoiding contact between the front work machine and the cab.

When the cab lift control device is installed in this way and the distance between the front attachment and the cab is less than a predetermined distance, the front work implement is operated to move the front attachment away from the cab before driving the lift device. By performing the second interference prevention control for avoiding the contact between the working machine and the cab, it is possible to prevent the front working machine from entering the interference prevention area and raise and lower the cab by a series of operations when the cab is moved up and down. Thus, the cab can be lifted and lowered without stopping the front working machine and the cab in the interference prevention area, and the working efficiency can be improved.

According to the present invention, when the cab is moved up and down, the cab can be moved up and down without stopping the front working machine and the cab within the interference prevention area, and the work efficiency can be improved.

It is a figure which shows the cab movable work machine in one embodiment of this invention. It is a figure which shows the raising/lowering operation of a cab. It is a figure which shows the hydraulic system mounted in the hydraulic excavator in this Embodiment, and its control system. It is a flow chart which shows the processing function concerning the 1st interference prevention control of a controller. It is a figure which shows the way of thinking which calculates the distance between a front attachment and a cab. It is a figure which shows the calculation table of the interference prevention control used by step S140 of FIG. It is a flow chart which shows the processing function concerning the 2nd interference prevention control of a controller. It is a figure which shows the locus|trajectory of an arm front-end|tip and the reference|standard height of an arm front-end when rotating an arm from the most pulled posture to the most pushed posture.

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

~Constitution~
FIG. 1 is a diagram showing a cab movable working machine according to an 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) 111a of the upper swing body 111 so as to be able to move up and down 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 arranged 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 fork grapple that grips waste such as concrete pieces with an openable fork and transports the waste to a truck bed or the like for loading. The front attachment 106 may be another working tool such as a lifting magnet that adsorbs and transfers waste such as iron scrap by the magnetic force of an electromagnet.

FIG. 2 is a view showing the raising/lowering operation of the cab 50. When the elevating cylinder 64 of the elevating device 60 is expanded and contracted, the parallel link mechanism 63 rotates about the connecting pin of the support frame 61 as a fulcrum, and the rotation of the parallel link mechanism 63 raises and lowers the cab 50. The upper cab 50 in FIG. 2 shows the lift cylinder 64 in the most extended position, and the cab 50 is in the highest position. The lower cab 50 is in the most retracted position, and the cab 50 is in the lowest position. Showing.

The hydraulic excavator including the cab 50 can perform work on the ground surface such as excavation work in the state where the cab 50 is lowered to the lowest position, like a general hydraulic excavator. On the other hand, when the cab 50 is raised to the highest position, the operator's eyes can be raised, and even if a container such as a trunk or a container is large, it is possible to work while looking at the inside from a wide field of view. it can.

Further, when the parallel link mechanism 63 rotates about the connecting pin of the support frame 61 as a fulcrum due to the expansion and contraction operation of the lifting cylinder 64, the cab 50 also moves in the front-rear direction while moving up and down, so that the cab moves between the lowest position and the highest position. At the intermediate position, as shown partially in FIG. 2, the most forward position (most advanced position) is obtained. Therefore, for example, when the cab 50 is lowered from the highest position, the front attachment may contact (interfere) with the cab 50 depending on the position of the front attachment 106. The present invention applies a technique for avoiding such contact between the front attachment 106 and the cab 50 when the cab is lifted.

FIG. 3 is a diagram showing a hydraulic system mounted on the hydraulic excavator according to the present embodiment and its control system.

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 detect the rotation angle of the parallel link mechanism 63 as a state quantity related to the height position of the cab 50. Link angle sensor 41 (height sensor), interference prevention control release switch 42, front operation mode/cab up/down mode mode switch 43, up/down switch 44 for instructing up/down of cab 50, angle sensor 31a, The sensor signals of 31b and 31c and the link angle sensor 41 and the switch signals of the interference prevention control release switch 42, the mode changeover switch 43 and the elevating switch 44 are input to perform the first and second interference prevention control (described later). A controller 45 for performing arithmetic processing, an electromagnetic switching type hydraulic lock valve 34 arranged between the discharge oil passage 7a of the pilot pump 7 and the pilot pressure supply oil passage 7b, and pilot lines 10a, 11a, 12a are provided. The electromagnetic proportional pressure reducing valves 33a, 33b, 33c, the electromagnetic proportional control valve 36 provided on the pilot line 17 branched from the pilot pressure supply oil passage 7b, the pressure of the arm pushing pilot line 11b (the output of the operating lever device 4b). Pressure) and the output pressure of the solenoid proportional control valve 36, whichever is higher, and outputs it to the pilot line 11b. The shuttle valve 37 (high pressure selection valve) and the pilot line 66a branched from the pilot pressure supply oil passage 7b. The electromagnetic proportional control valves 67a and 67b provided in 66b, the monitor 46, and the warning buzzer 47 are provided.

An inertial sensor may be used instead of the angle sensors 31a, 31b, 31c to detect the position and orientation of the front working machine 103. Further, instead of the link angle sensor 41, a stroke sensor that detects the stroke of the lifting cylinder 64 may be used to detect the state quantity related to the height position of the cab 50.

The interference prevention control release switch 42, the mode changeover 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 mode changeover switch 43 is, for example, a seesaw-type switch that switches between the front operation mode and the cab lifting mode.

The front operation mode is a mode used when the cab 50 is stopped at a predetermined position to perform work. In the front work mode, the front attachment 106 is in the interference prevention area while the interference prevention control release switch 42 is OFF. The interference prevention control (first interference prevention control) for avoiding the contact between the front attachment 106 and the cab 50 when the vehicle 70 (see FIG. 1) enters is effective. Further, in the front work mode, the raising/lowering switch 44 is invalidated, and even if the raising/lowering switch 44 is operated, the cab 50 cannot be raised or lowered.

The cab raising/lowering mode is a mode used when raising/lowering the cab 50, and the cab 50 can be raised/lowered by operating the raising/lowering switch 44 in the cab raising/lowering mode. Further, in the cab raising/lowering mode, the interference prevention control (second interference prevention control) for avoiding the interference between the front attachment 106 and the cab 50 when the cab 50 is raised and lowered is effective.

The elevating switch 44 is a switch that is effective when the front work mode is set, and includes an ascending direction instruction switch 44a and a descending 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 pressed and instruct to move the cab 50 up and down.

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 valve 36 generates 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 the shuttle. It is guided to the pressure-receiving portion 21b of the flow control valve 5b, which is pushed by the arm, through the 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 arm pressure-receiving portion 21b of the flow control valve 5b of the arm 105.

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.

Here, the interference prevention area 70 related to the first interference prevention control will be described.

The interference prevention area 70 is set on the front side, the upper side, and the lower side of the cab 50, as shown in FIG. 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.

The controller 45 and the electromagnetic proportional pressure reducing valves 33a, 33b, 33c operate the front working machine 103 when the front working machine 103 is operated and the front attachment 106 enters the interference prevention area 70 set around the cab 50. An interference prevention device that performs the first interference prevention control that restricts and avoids the contact between the front attachment 106 and the cab 50 is configured.

Further, the controller 45, the electromagnetic proportional control valve 36, and the shuttle valve 37 are based on the switch signal of the up/down switch 44 and the detection values of the angle sensors 31a, 31b, 31c (posture sensor) and the link angle sensor 41 (height sensor). Thus, a cab raising/lowering control device that controls the operation of the front working machine 103 when the cab 50 is raised and lowered is configured.

The cab lifting control device, when the lifting switch 44 is operated, based on the switch signal of the lifting switch 44 and the detection values of the angle sensors 31a, 31b, 31c (posture sensor) and the link angle sensor 41 (height sensor). , A distance D (described later) between the front attachment 106 and the cab 50 is calculated, and when the distance D is larger than a predetermined distance Xo (described later), the lifting device 60 is driven, and the distance D between the front attachment 106 and the cab 50 is reduced. When the distance is equal to or less than the predetermined distance Xo, the front work implement 103 is operated so that the front attachment 106 is separated from the cab 50 before the lifting device 60 is driven, and the contact between the front work implement 103 and the cab 50 is avoided. 2 Performs interference prevention control.

The details of the first interference prevention control and the second interference prevention control will be described below.

-First interference prevention control-
FIG. 4 is a flow chart showing the processing functions related to the first interference prevention control of the controller 45.

When the mode changeover switch 43 indicates the front operation mode, the controller 45 starts the first interference prevention control shown by the flowchart in FIG.

In this first interference prevention control, the controller 45 first determines whether or not the interference prevention control release switch 42 is pressed (step S100), and when the interference prevention control release switch 42 is pressed, the controller 46 displays it on the monitor 46. A display (for example, a message display) indicating that the interference prevention control release switch 42 is pressed (interference prevention control is released) is displayed, and the operator visually recognizes that the interference prevention control release switch 42 is pressed. The warning 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 calculates 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 stored in the memory (for example, ROM) in advance ( 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.

Further, the controller 45 detects the rotation angles of the boom 104, the arm 105, and the front attachment 106 detected by the angle sensors 31a, 31b, and 31c, and the dimensions of the front member and the cab 50 that are stored in advance in a memory (for example, ROM). The distance D between the front attachment 106 and the cab 50 is calculated from the above (step S115).

FIG. 5 is a diagram showing the concept of calculating the distance D between the front attachment 106 and the cab 50.

In FIG. 5, the fork grapple as 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 bracket 106a attachment link 106c is rotatably pin-coupled with a pin 106d, one end of the arm link 105a is rotatably pin-coupled with the arm 105, and the piston rod of the arm cylinder 3c is attached to the attachment link 106c. The other end is rotatably pin-connected to 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 distance D between the front attachment 106 and the cab 50 is calculated as the distance between the 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 first and second interference prevention control of the present invention, which is set around the cab 50 in consideration of the protrusions and the like of the cab 50.

The representative point of the front attachment 106 is a virtual circle that includes the front actuator 106, and is, for example, a virtual circle that passes through the pin 106b of the bracket 106a (the rotation fulcrum of the front attachment 106 at the tip of the arm 105) and another pin 106d. SC is set, and it is set as a point (closest point) R closest to the cab 50 on this virtual circle SC. 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 and the like of the front attachment 106 including the cab 50 and the bracket 106a stored in, the position closest to the reference contour line CR of the cab 50 on the virtual circle SC, that is, the reference contour line of the virtual circle SC and the cab 50. It is calculated as a position on the virtual circle SC where the distance D between CRs is the smallest.

The distance D between the front attachment 106 and the cab 50 is calculated as the distance between (the closest point R of) the virtual circle SC and the reference contour line CR of the cab 50, that is, the closest distance.

The virtual circle that sets the representative point of the front actuator 106 is not limited to the virtual circle SC that passes through the rotation fulcrum (pin 106b) and the pin 106d, and any other virtual circle that includes the front actuator 106 can be used. May be For example, another virtual circle may be an envelope circle that includes the rotation fulcrum (pin 106b) as a part of an arc and includes the entire front attachment 106.

Here, 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 the 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 performs interference prevention control (step S140).

FIG. 6 is a diagram showing a calculation table for interference prevention control used in step S140. This calculation table is stored in advance in the memory (for example, ROM) of the controller 45.

6, the horizontal axis represents the distance D between the front attachment 106 and the cab 50 calculated in step S115, 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 a value calculated as the most recent distance between the virtual circle SC of the front attachment 106 and the reference contour line CR of the cab 50, as described above.

In the calculation table of FIG. 6, 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, 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 S140, the controller 45 reads the operation table of FIG. 6 from the memory, refers to the distance D (closest distance) calculated in step S115 in the operation table, and determines the front and rear pressures of the electromagnetic proportional pressure reducing valves 33a, 33b, 33c. The ratio Rp is calculated, and a 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.

That is, when the distance D>the first threshold value D1, the controller 45 calculates 0% as the front-rear pressure ratio Rp, and uses the control current corresponding to the front-rear pressure ratio 100% as an electric signal to generate the electromagnetic proportional pressure reducing valves 33a, 33b, 33c. Is output (step S145). In this case, the electromagnetic proportional pressure reducing valves 33a, 33b, 33c are fully opened, and the front member of the front working machine 103 is driven at a speed according to the command pilot pressure generated by the operating lever devices 4a, 4b, 4c.

On the other hand, when the second threshold value D2<the distance D≦the first threshold value D1, the controller 45 calculates a value corresponding to the distance D as the front-rear pressure ratio Rp, and uses the control current corresponding to the front-rear pressure ratio Rp as an electric signal. Output 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 reduce the operation of the front member of the front working machine 103.

When the distance D≦second threshold value D2, the controller 45 calculates 0% as the front-rear pressure ratio Rp, and uses the control current corresponding to the front-rear pressure ratio 0% as an electric signal to generate the electromagnetic proportional pressure reducing valves 33a, 33b, 33c. Is output (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.

Thus, as the distance D, the cab 50 is calculated by performing the first interference prevention control by calculating the closest distance between the virtual circle SC of the front attachment 106 and the reference contour line CR of the cab 50. At any height position (whether the cab 50 is in the raised and lowered positions, or in an intermediate position where the cab 50 is forward of the raised and lowered positions), the front attachment 106 is When entering the interference prevention area 70 (see FIG. 1 ), it is possible to avoid contact between the front attachment 106 and the cab 50 based on the closest distance D thereof. Further, when the front attachment 106 is in any positional relationship with the reference contour line CR of the cab 50 (not only when the front attachment 106 is on the front side of the reference contour line CR, but also on the upper side or the lower side of the reference contour line CR). When the front attachment 106 enters the interference prevention area 70 (see FIG. 1), the interference prevention control for avoiding the contact between the front attachment 106 and the cab 50 is performed based on the closest distance D thereof. Is possible.

-Second interference prevention control-
FIG. 7 is a flowchart showing the processing function of the controller 45 relating to the second interference prevention control.

The controller 45 starts the second interference prevention control shown by the flowchart in FIG. 7 when the mode changeover switch 43 indicates the cab lifting mode. At this time, the controller 45 gives a display (for example, a message display) to the monitor 46 to inform that it is in the cab lifting mode so that the operator can visually confirm that it is in the cab lifting mode and activates the warning buzzer 47. Then, a warning sound is generated so that the operator can hear it. In addition, when the cab raising/lowering mode is instructed, the controller 45 can distinguish 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 from a different mode from that time. Is displayed and a warning sound is generated.

Next, the controller 45 determines whether the up/down switch 44 is operated in either the up direction or the down direction to be ON (step S205), and when the up/down switch 44 is OFF, does nothing and repeats the processing. .. On the other hand, when the up/down switch 44 is ON, a display (for example, a message display) indicating that the up/down switch 44 is pressed is displayed on the monitor 46, and the operator visually recognizes that the up/down switch 44 is pressed. The warning buzzer 47 is activated to generate a warning sound so that the operator can hear it. Also at this time, the controller 45 can distinguish from 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 and when the cab lifting mode is instructed. Displays in a different manner and generates a warning sound.

When the elevating switch 44 is ON, the controller 45 first performs the same processing as steps S105, S110, and S115 of the first interference prevention control shown in FIG.

That is, in step S210, the sensor signals from the angle sensors 31a, 31b, 31c and the link angle sensor 41 are input, and in step S215, the controller 45 detects the rotation angle of the parallel link mechanism 63 detected by the link angle sensor 41. The height of the cab 50 is calculated from the dimensions and the like of the parallel link mechanism 63 stored in advance in a memory (for example, ROM). As the height of the cab 50, for example, it is preferable to calculate the height of the lower surface of the cab 50.

Further, the controller 45, in step S220, the rotation angles of the boom 104, the arm 105, and the front attachment 106 detected by the angle sensors 31a, 31b, and 31c, and the front members and the front members stored in advance in the memory (for example, ROM). The distance D between the front attachment 106 and the cab 50 is calculated from the dimensions of the cab 50 and the like. As the distance D, the closest distance between (the closest point R of) the virtual circle SC of the front attachment 106 and the reference contour line CR of the cab 50 is calculated.

Next, the controller 45 determines whether or not the distance D (closest distance) calculated in step S220 is larger than a preset predetermined distance Xo (whether D>Xo) (step S225). This determination is performed to determine whether or not the cab 50 may interfere (contact) with the front working machine 103 when the cab 50 is moved up and down, and the predetermined distance Xo is determined from the reference contour line CR of the cab 50. It is set as a distance to any position in the deceleration area A of the interference prevention area 70. In the present embodiment, the predetermined distance Xo is equal to the distance from the reference contour line CR of the cab 50 to the boundary between the deceleration area A and the non-interference prevention area, that is, the threshold value D1 described above, for example, as shown in FIG. It is set as a distance.

In step S225, if D>Xo, that is, if there is no risk of the front working machine 103 interfering with the cab 50 when the cab 50 is moved up and down, the controller 45 electromagnetically changes the cab lifting control signal (electrical signal). It is sent to the control valve 67a or 67b, and the raising/lowering operation of the cab 50 is performed (step S230).

On the other hand, when D≦Xo, that is, when the front working machine 103 may interfere with the cab 50 when the cab 50 is moved up and down, the controller 45 controls the angle sensor 31a of the boom 104 and the angle sensor 31b of the arm 105. The tip position of the arm 105 is calculated based on the sensor signal (step S235), and it is determined whether the tip position of the arm 105 is the reference height Ho or more (step S240). This determination is to determine whether or not the front attachment 106 may come into contact with the ground when the arm 105 is in the vertical posture by the pushing operation of the arm 105 in step S250 described later.

Hereinafter, the case where the tip position of the arm 105 is lower than the reference height Ho and the case where it is equal to or higher than the reference height Ho will be described separately.

<When the arm tip position is lower than the reference height Ho>
FIG. 8 is a diagram showing the locus of the arm tip and the reference height Ho of the arm tip when the arm 105 is rotated from the most pulled posture to the most pushed posture. La is the arm tip position in the most pulled posture of the arm 105, Lb is the arm tip position in the vertical posture of the arm 105, Lc is the arm tip position in the most pushed posture of the arm 105, and E is the arm tip position between La and Lb. A rotation range of the arm 105, F is a rotation range of the arm 105 between the arm tip position Lb to the position Lc.

When the arm 105 is pushed from the most pulled position, the arm 105 rotates in a circular arc around the pin 105b connecting the boom 104 and the arm 105, and the lowermost point of the arc (directly below the pin 105b). ), the arm 105 moves in the horizontal direction with respect to the ground and moves in the vertical direction to approach the ground. Therefore, when the tip of the arm 105 is located too close to the ground, the front attachment 106 may come into contact with the ground when the arm 105 is in the vertical posture due to the pushing operation of the arm 105 in step S250 described later.

In step S240, in order to prevent the front attachment 106 from coming into contact with the ground, it is determined whether the tip position of the arm 105 is equal to or higher than the reference height Ho. At this time, the controller 45 calculates the reference height Ho of the tip position of the arm 105 as follows.

The controller 45 calculates the height deviation ΔH of the tip position when the arm 105 rotates from the current position to the vertical posture based on the sensor signal of the angle sensor 31b of the arm 105, and calculates the height deviation ΔH as the front deviation. The diameter Ra of the virtual circle SR including the attachment 106 is added, and the value is set as the reference height Ho. That is, Ho=ΔH+Ra is calculated.

The reference height Ho may be calculated by providing a margin for the diameter Ra of the virtual circle SR. Further, at this time, the setting value of the reference height Ho may be changed by changing the margin allowance in consideration of the fact that the situation of the undercarriage at the site is different for each site.

When it is determined in step S240 that the arm tip position is lower than the reference height Ho, the controller 45 activates the warning buzzer 47 to generate a warning sound to warn the operator (step S245). At this time, the controller 45 distinguishes between the warning sounds when the interference prevention control release switch 42 is pressed, when the cab lifting mode is instructed, and when the lifting switch 44 is turned on. Generates a different warning sound than when.

Accordingly, there is a risk that the front attachment 106 comes into contact with the ground or the like, so that it is possible to notify that the arm push control in step S250 cannot be performed and that the operator needs to perform a manual operation.

<When the arm tip position is higher than the reference height Ho>
When it is determined in step S240 that the tip position of the arm 105 is equal to or higher than the reference height Ho, the controller 45 sends a control signal to the electromagnetic proportional control valve 36 connected to the arm pushing pilot line 11b via the shuttle valve 37. The output is performed and the pushing operation of the arm 105 is performed (step S250).

The reason why the pushing operation of the arm 105 is performed is that the front attachment 106 moves away from the cab 50 regardless of the positional relationship between the cab 50 and the front working machine 103 when the arm 105 is pushed.

Next, the controller 45 determines whether the detection value of the angle sensor 31b of the arm 105 is equal to a preset reference angle θo (step S255), and the detection value of the angle sensor 31b of the arm 105 is equal to the reference angle θo. The pushing operation of the arm 105 is continuously performed until. The reference angle θo is an angle at which the front attachment 106 is separated from the cab 50 to a position where the front attachment 106 does not interfere with the cab 50 due to the pushing operation of the arm 105 when the cab 50 is moved up and down. It is preferable that the reference angle θo can also be changed.

Further, in step S255, it is determined whether or not the elevating switch 44 is ON until the detected value of the angle sensor 31b of the arm 105 becomes equal to the reference angle θo (step S260), and the elevating switch 44 is turned OFF. Return to start and repeat the steps above.

In step S255, when the detection value of the angle sensor 31b of the arm 105 becomes equal to the reference angle θo, the process proceeds to step S230, in which the controller 45 sends a cab lifting control signal (electrical signal) to the electromagnetic proportional control valve 67a or 67b. The raising/lowering operation of the cab 50 is performed.

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

1. A cab raising/lowering control device (controller 45, electromagnetic proportional control valve 36, and shuttle valve 37) is provided, and when the raising/lowering switch 44 is operated, when the distance between the front attachment 106 and the cab 50 is a predetermined distance Xo or less, raising/lowering is performed. Before the device 60 is driven, the front work implement 103 is operated so that the front attachment 106 is separated from the cab 50, and the second interference prevention control for avoiding the contact between the front work implement 103 and the cab 50 is performed. When the cab is moved up and down, it is possible to prevent the front working machine 103 from entering the interference prevention area and raise and lower the cab 50 by a series of operations, whereby the front working machine 103 and the cab 50 stop within the interference prevention area 70. The cab 50 can be raised and lowered without the operation, and the work efficiency can be improved.

2. In the second interference prevention control, the controller 45 determines whether or not the front attachment 106 may come into contact with the ground when the arm 105 is in the vertical posture due to the pushing operation of the arm 105, and the front attachment 106 comes to the ground. Since a warning is generated when there is a possibility of contact, it is possible to avoid the risk of the front attachment 106 contacting the ground during the arm pushing operation by the second interference prevention control.

3. The interference prevention device (the controller 45 and the electromagnetic proportional pressure reducing valves 33a, 33b, 33c) uses the distance D between the virtual circle SC of the front attachment 106 (the closest contact R thereof) and the reference distance CR of the cab 50 as the closest distance. The first interference prevention control is calculated and performed. This allows the cab 50 to be at any height position (whether the cab 50 is in the uppermost position and the lowermost position, or in an intermediate position where the cab 50 is forward of the uppermost position and the lowermost position). When the front attachment 106 enters the interference prevention area 70 (see FIG. 1 ), it is possible to perform the interference prevention control for avoiding the contact between the front attachment 106 and the cab 50 based on the closest distance D. Further, when the front attachment 106 is in any positional relationship with the reference contour line CR of the cab 50 (not only when the front attachment 106 is on the front side of the reference contour line CR, but also on the upper side or the lower side of the reference contour line CR). When the front attachment 106 enters the interference prevention area 70 (see FIG. 1), the interference prevention control for avoiding the contact between the front attachment 106 and the cab 50 is performed based on the closest distance D thereof. Is possible.

4. Also in the cab lift control device (controller 45, electromagnetic proportional control valve 36, and shuttle valve 37), the distance D is set between the virtual circle SC of the front attachment 106 (closest contact point R) and the reference contour line CR of the cab 50. Since the distance is calculated and the second interference prevention control is performed, the front attachment 106 is in any positional relationship with the reference contour line CR of the cab 50 (only when the front attachment 106 is in front of the reference contour line CR). (Even when it is above or below the reference contour line CR), it is possible to avoid the intrusion into the interference prevention area of the front working machine 103 and move the cab 50 up and down by a series of operations when the cab is moved up and down.

3a to 3g Hydraulic actuators 4a to 4g Operating lever devices 5a to 5g Flow control valve 5b Arm flow control valve 21b Arm pressure control valve arm pressure receiving parts 31a, 31b, 31c Angle sensor (posture sensor)
33a, 33b, 33c Electromagnetic proportional pressure reducing valve (interference prevention device)
36 Electromagnetic proportional control valve (cab lifting control device)
37 Shuttle valve (high pressure selection valve)
41 Link angle sensor (height sensor)
42 Interference prevention control release switch 43 Mode selection switch 44 Lift switch 45 Controller (interference prevention device, cab lift control device)
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 Interference Prevention Area 100 Vehicle Body 103 Front Working Machine 104 Boom 105 Arm 106 Front Attachment (Fork Grapple)
110 Lower traveling structure 111 Upper revolving structure A Deceleration area B Stopping area Xo Predetermined distance CR Reference contour line of cab SR Virtual circle of front attachment

Claims (6)

A vehicle body with a cab that can be raised and lowered,
A front working machine having a plurality of front members including front attachments, which are rotatably connected in the vertical direction to the vehicle body and rotatably connected to each other in the vertical and front-rear directions;
A plurality of hydraulic cylinders that drive the plurality of front members,
An elevating device for elevating the cab with respect to the vehicle body,
When the front work implement is operated and the front attachment enters the interference prevention area set around the cab, the operation of the front work implement is limited to avoid contact between the front attachment and the cab. In a cab movable work machine including an interference prevention device that performs a first interference prevention control,
An elevating switch for instructing elevating the cab,
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,
A cab lifting control device that controls the operation of the front working machine when the cab is lifted based on the switch signal of the lift switch and the detection values of the attitude sensor and the height sensor,
The cab lifting control device calculates a distance between the front attachment and the cab based on detection values of the posture sensor and the height sensor when the lifting switch is operated, and the distance is less than a predetermined distance. When it is large, the lifting device is driven, and when the distance between the front attachment and the cab is less than the predetermined distance, the front work is performed so that the front attachment is separated from the cab before driving the lifting device. A movable cab working machine, characterized in that the machine is operated to perform a second interference prevention control for avoiding contact between the front working machine and the cab. The cab movable work machine according to claim 1,
The interference prevention area of the first interference prevention control has a deceleration area and a stop area,
The movable cab working machine, wherein the predetermined distance is set as a distance from a reference contour line of the cab to any position in the deceleration area. The cab movable work machine according to claim 1,
The plurality of front members are configured by connecting a boom and an arm and the front attachment so as to be rotatable in a vertical direction and a front-back direction.
When performing the second interference prevention control, the cab lifting control device operates the front working machine so that the front attachment is separated from the cab by performing a pushing operation of the arm. Work machine. The movable cab working machine according to claim 3,
The cab lifting control device determines whether the front attachment may come into contact with the ground when the arm is in a vertical posture due to the pushing operation of the arm, and the front attachment may come into contact with the ground. A cab movable working machine, which is characterized by generating a warning when there is an error. The cab movable work machine according to claim 1,
The cab raising/lowering control device sets a virtual circle including the front attachment, and calculates a distance between the front attachment and the cab as a closest distance between the virtual circle and the cab. Movable work machine. The cab movable work machine according to claim 1,
The plurality of front members are configured by connecting a boom and an arm and the front attachment so as to be rotatable in a vertical direction and a front-back direction.
The cab lifting control device,
A controller,
An electromagnetic proportional control valve driven by a control signal output from the controller,
A pilot circuit for guiding the output pressure of the electromagnetic proportional control valve to the arm pressure receiving portion of the flow control valve of the arm,
When the distance between the front attachment and the cab is equal to or less than the predetermined distance, the controller outputs the control signal to the electromagnetic proportional control valve to perform a pushing operation of the arm, whereby the front attachment is A movable cab working machine, characterized in that the front working machine is operated to move away from the cab.

Images