JPH11280106A - Interference prevention device of construction machinery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an interference prevention device of construction machinery capable of promoting working efficiency while ensuring safety in an interference area. SOLUTION: When a bucket enters the inside of an interference area, for example, a pressure reducing valve 16a reduces pilot pressure to an arm flow controlling valve 14, the flow rate of hydraulic fluid supplied to an arm cylinder 6 is controlled, and a moving speed of the bucket is decelerated. After the bucket is decelerated and is stopped, when an operator pushes a releasing switch down to output a releasing command, a controller 4 receiving the releasing command gradually releases the flow rate of the controlled hydraulic fluid. By the constitution, even in the case interference prevention is released in such a state as manipulated variable of a control lever 13a remains unchanged, the bucket generously operates without suddenly starting operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for preventing interference applied to construction machines such as hydraulic excavators.

[0002]

2. Description of the Related Art Conventionally, in a hydraulic excavator in which an arm can be offset in the left-right direction of a cab for digging a ditch, an interference region occurs in which a bucket interferes with the cab within a movement range of a front attachment. An interference preventing device is provided so that the bucket does not collide with the cab.

In this type of interference prevention apparatus, for example, an interference area is virtually set up to a position at a predetermined distance from the outer surface of the cab, and when a bucket enters the interference area, the moving speed of the bucket is reduced. While the operation is stopped automatically.

In this state, the operating lever can be operated in the direction in which the bucket moves away from the cab, but there is a limit in the direction in which the bucket is moved further closer to the cab. Specifically, when operating the operation lever to the cab side, the operating oil is supplied to the cylinder even if the operation lever is operated unless the automatic stop release switch provided on the operation lever is pressed. I am not able to do it. Thereby, the operator can operate the front attachment while grasping that the operator is working in the interference area.

[0005]

However, even if the operator recognizes that he or she is performing work in the interference area, the operation lever is automatically returned to the interference side without returning to the neutral position. When the stop release switch is pressed, the supply of the hydraulic oil to the cylinder is immediately released by 100%, so that the bucket suddenly starts moving and the load in the bucket falls. Therefore, in order to ensure safety, the operator must return the operation lever to the neutral position once each time the interference prevention works and the automatic stop is performed, and the workability in and around the interference area is significantly impaired. I was

The present invention has been made in view of the above circumstances, and provides an interference prevention device for a construction machine capable of improving workability while ensuring safety in an interference area. .

[0007]

SUMMARY OF THE INVENTION According to the present invention, an interference area is virtually set up to a position separated from an operator's cab by a predetermined distance, and a front which moves in a direction interfering with the operator's cab within the interference area. In an interference prevention device for decelerating an attachment and automatically stopping the attachment, a flow limiting means for limiting a flow rate of hydraulic oil supplied to a front attachment drive hydraulic cylinder until the front attachment is stopped, and an interference prevention release command are output. Cancellation instruction means,
When a release command is output from the release instruction means while the flow of hydraulic oil is restricted and the front attachment is stopped, the flow restriction signal that restricts the hydraulic oil supply flow to the front attachment drive hydraulic cylinder is gradually released. And a restriction canceling means.

In the present invention, it is preferable that the restriction of the hydraulic oil is released only during the period when the release instruction is output from the release instruction means.

In the present invention, it is preferable that the flow rate restriction of the hydraulic oil is immediately returned to the maximum when the output of the release command is stopped.

According to the present invention, when the front attachment enters the interference area, the flow restricting means restricts the flow rate of the working oil supplied to the hydraulic cylinder for driving the front attachment and reduces the moving speed of the front attachment. After the front attachment has been decelerated and stopped, when the operator outputs a release command via the release instruction means, the restriction release means receiving the release command gradually releases the restricted flow rate of the working oil. Thereby,
For example, even if the interference prevention is canceled while the operation amount of the operation lever is large, the front attachment does not operate rapidly but starts operation slowly. That is, it is possible to safely restart the operation without returning the operation lever to the neutral position.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. FIG. 1 shows a hydraulic control device according to the present invention. In the figure, reference numeral 1 denotes a hydraulic pump for supplying hydraulic oil for driving a hydraulic cylinder, 2
Reference numeral denotes a pilot hydraulic pump that supplies pilot pressure, and reference numeral 3 denotes an oil tank that collects hydraulic oil. Reference numeral 4 denotes a controller constituted by a microcomputer, which receives an operation command output from an operation lever and a detection signal detected by each detection unit, and controls each cylinder, specifically a boom cylinder 5 for driving a boom, and an arm. The operation of the arm cylinder 6 to be driven and the operation of the offset cylinder 7 for performing offset are controlled, and the cylinder speed is reduced at the stroke end.

A pressure reducing valve 1 is provided on a pilot line 10a between the boom raising operation lever 8a and the boom flow control valve 9.
The operation amount of the boom raising operation lever 8a is detected by a boom raising operation amount detection sensor 12a. On the other hand, the boom lowering operation lever (operation body) 8
Pilot line 1 between b and boom flow control valve 9
0b is provided with a pressure reducing valve 11b, and the operation amount of the boom lowering operation lever 8b is controlled by the boom lowering operation amount detecting sensor 1b.
2b. Each of the above-described cylinders can be regarded as a front attachment driving hydraulic cylinder.

A pressure reducing valve 16a is provided on a pilot line 15a between the arm pulling operation lever 13a and the arm flow control valve 14, and the operation amount of the arm pulling operation lever 13a is detected by an arm pulling operation amount detection. Sensor 17
a.

A pressure reducing valve 16b is provided in a pilot line 15b between the arm pushing operation lever 13b and the flow control valve 14 for the arm, and the operation amount of the arm pushing operation lever 13b is determined by an arm pushing operation amount detecting sensor 17b. Is detected by

A pilot line 2 between the offset left operation pedal 18a and the offset flow control valve 19 is provided.
0a is provided with a pressure reducing valve 21a, and the operation amount of the offset left operation pedal 18a is detected by an offset operation amount detection sensor 22a. A pressure reducing valve 21b is provided in a pilot line 20b between the offset right operation pedal 18b and the offset flow control valve 19, and the operation amount of the offset right operation pedal 18b is detected by an offset operation amount detection sensor 22b.

The above-described operation amount detection sensors 12a, 12
The detection signals output from b, 17a, 17b, 22a and 22b are given to the controller 4. Each of the pressure reducing valves can be regarded as a flow restricting means.

FIG. 2 shows the configuration of a hydraulic shovel having the above hydraulic circuit. In the figure, in a hydraulic shovel 30, a cab (operating cab) 33 is mounted on a swivel base 32 supported by a traveling device 31, and a front attachment is arranged at a side position of the cab 33. The front attachment includes a boom 34 that rotates up and down,
It is composed of an offset boom 35 that swings in the left-right direction, an arm 36 that pushes and pulls in the front-rear direction, and a bucket 37 provided at the tip of the arm 36.

The boom 34 is driven by the boom cylinder 5 described above. That is, by operating the boom raising operation lever 8a and the boom lowering operation lever 8b shown in FIG.
Controls the flow direction and flow rate of the hydraulic oil, and the boom cylinder 5 is driven by receiving the controlled hydraulic oil.

The offset boom 35 is driven by the above-described offset cylinder 7, and the offset cylinder 7 is operated by the offset flow control valve 19 by operating the offset left operation pedal 18a and the offset right operation pedal 18b. Drives by receiving oil.

The arm 36 is provided with the arm cylinder 6 described above.
The arm cylinder 6 is driven by operating the arm pulling operation lever 13a and the arm pushing operation lever 13b to receive the hydraulic oil controlled by the arm flow switching valve 14. Note that the bucket 37
It is designed to rotate with a bucket cylinder (not shown). In FIG. 2, reference numeral 5a denotes a boom angle detector for detecting the vertical rotation angle of the boom 34;
a is an arm angle detector for detecting the forward / backward rotation angle of the arm 36, and 7a is an offset angle detector for detecting the left / right swing angle of the offset boom 35.

The cab 3 of the excavator 30
3, an interference plane P is virtually set at a position outside the cab 33 by a predetermined distance L1.
The interference area Q is set between the position and the position further away from the position by a predetermined distance L2. Then, in the interference area Q, control is performed such that the moving speed of the front attachment moving in the direction of the cab 33 is reduced, and the movement of the front attachment is stopped at the interference plane P.

That is, when the positions of the boom 34, the offset boom 35, and the arm 36 constituting the front attachment enter the interference area Q, the ROM 4a of the controller 4 shown in FIG. On the other hand, data for outputting a pressure reduction command is stored. This interference control employs the same control method as the conventional interference control.

A pressure-reducing command output from the ROM 4a to each pressure-reducing valve is branched and input to a restriction-releasing unit (restriction-releasing means) 4b of the controller 4, whereby the flow rate control valves 9, 14,. It can be seen that the pilot pressure supplied to 19 is reduced. The control release section 4b is provided with a release switch 23 as a release instruction means.
Is activated by pressing the button. The release switch 23 is provided above the operation lever, and can operate the operation lever while pressing the release switch 23.

FIG. 3 is a time chart showing the operation of the restriction release section 4b. In FIG.
Represents the distance between the interference plane P (assumed to be zero) and the bucket over time, the + side indicates the outside of the interference plane P,
The negative side indicates the inside of the interference plane P. (C) shows a release signal output when the release switch 23 is pressed, and (b) shows a deceleration command output from the restriction release unit 4b when the release signal is output.

As shown in FIG. 3, as the bucket approaches the interference plane P, the controller 4 gradually increases the deceleration of the deceleration command (flow rate limiting signal) output to each deceleration valve. Maximize the deceleration (S in FIG. 3B)
₁ ) do. Therefore, in this state, the operation of moving the bucket to the cab cannot be performed.

The operator can recognize that the bucket has entered the inside of the interference plane P because the bucket does not move despite operating the operation lever. In such a situation, if there is no possibility that the movement of the bucket to the interference side immediately collides with the cab, the stopped bucket may be desired to be continuously moved to the interference side by the operator's judgment. Therefore, if the release switch 23 is pressed without returning the operation lever to the neutral position, the release command signal S shown in FIG.
₂ is output and given to the restriction release unit 4b of the controller 4.

Release command signal S_Two Restriction release unit 4b that received
Is the deceleration command S with the maximum deceleration. ₁ Gradually release
Go. That is, the fall of the deceleration command when releasing the deceleration
Slip (S in FIG. 3B)_Three ) To give a gradient
For example, by operating the arm pushing operation lever 13b,
The pilot pressure derived from the valve gradually controls the flow rate for the arm.
It acts on the pilot port of the valve 14.
Releasing gradually means that the deceleration changes from maximum to minimum, for example.
By setting the time to change to 3 seconds
It is.

When the operator releases his / her finger from the release switch 23 while the operation is being performed inside the interference plane P, the deceleration command immediately rises from the released state (S in FIG. 3B).
_4), the maximum deceleration S ₅ in (Figure 3 (b)).

In the cab interference prevention, the degree of deceleration at the time of boom raising, arm pulling, and offset left operation is changed according to the distance between the cab and the bucket. Of these three operation patterns, the operation directions of the boom raising and the arm pulling are limited to the front-rear direction and the vertical direction. Therefore, when the bucket is positioned off the side of the cab, there is no need to decelerate at all. Specifically, even when the cab side is closer to the cab side beyond the interference area, the boom is raised, and the arm pulling operation does not output a deceleration command according to the lateral distance between the bucket and the cab. . Furthermore, by setting the interference surface (stop surface) of the boom raising and arm pulling to a side closer to the cab than the interference surface at the offset left, the boom raising and the arm pulling can be performed even when stopped by the offset left operation. It can be driven and operability can be improved. In this case, stop with the cab interference prevention, perform the offset right operation while the boom is being raised or the arm is being pulled (the bucket moves rightward along the cab interference stop surface), and the interference on the side of the cab When the user moves away from the surface, the stop command for raising the boom and pulling the arm may be suddenly canceled and start moving. At this time, if the deceleration command given to the deceleration means by exceeding the interference surface on the side surface of the cab is gradually released over a certain period of time, the boom raising and / or the arm pulling operation may be rapidly performed. It does not occur and starts to move smoothly.

In the above embodiment, the interference prevention device of the present invention is applied to a hydraulic excavator. However, the present invention is not limited to this, and can be applied to any construction machine that operates a front attachment.

[0031]

As is apparent from the above description,
ADVANTAGE OF THE INVENTION According to this invention, the interference prevention apparatus of a construction machine which can improve workability | operativity while ensuring the safety in an interference area can be provided.

Further, in the present invention, when the output of the release command is stopped, the flow restriction of the hydraulic oil is immediately returned to the maximum. Therefore, when the release of the interference prevention is completed in the interference area, the movement of the front attachment is stopped. Can be stopped immediately.

[Brief description of the drawings]

FIG. 1 is a hydraulic control circuit diagram according to the present invention.

FIG. 2 is an overall view of a hydraulic shovel to which the present invention is applied.

FIG. 3 is a time chart for explaining the operation of the interference prevention device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic pump 2 Pilot hydraulic pump 3 Oil tank 4 Controller (restriction release means) 5 Boom cylinder 6 Arm cylinder 7 Offset cylinder 9 Boom flow control valve 11a Pressure reducing valve (Flow restriction means) 14 Arm flow control valve 19 Offset flow control Valve 23 release switch (release instruction means)

Claims (3)

[Claims] 1. An interference area is virtually set between a position at a predetermined distance from a driver's cab and a front attachment moving in a direction interfering with the driver's cab is decelerated and automatically stopped within the interference area. In the interference prevention device, a flow restricting unit that restricts a flow rate of hydraulic oil supplied to the front attachment driving hydraulic cylinder until the driving of the front attachment is stopped, a cancellation instruction unit that outputs a cancellation command of interference prevention, When a release command is output from the release instruction means in a state where the flow rate of the hydraulic oil is limited and the drive of the front attachment is stopped, a flow rate limiting signal for limiting a hydraulic oil supply flow rate to the front attachment drive hydraulic cylinder is output. And a restriction releasing means for gradually releasing the restriction. Stop device. 2. The construction machine interference prevention device according to claim 1, wherein the restriction of the hydraulic oil is released only during a period in which a release command is output from the release instruction means. 3. The construction machine interference prevention device according to claim 1, wherein the flow rate restriction of the hydraulic oil is immediately returned to the maximum when the output of the release command is stopped.