JPS6337211B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shovel work vehicle such as a backhoe or a face excavator, in particular, a boom 8 is attached to a swivel base 2 so as to be able to swing up and down, and an arm 9 that can be freely extended and retracted is mounted on the boom 8. Attached for easy operation,
The present invention relates to a shovel vehicle equipped with a bucket 10 rotatably attached to the arm 9 and a hydraulic cylinder for driving the bucket.

This type of shovel vehicle is used for digging trenches and other excavation work, but with conventional work vehicles, it is extremely difficult to accurately excavate to a predetermined depth. In other words, it is difficult for the operator on the work vehicle to see the excavated area, and it is especially difficult to visually estimate the depth of excavation.Furthermore, due to the extension and contraction of the arm, the swing angle of the boom and arm and the excavation depth are extremely difficult to see. The correlation with depth varied greatly, so excavation had to be done mostly by intuition. Moreover, even if an assistant person is assigned to monitor the excavation depth, since the depth is measured by eye, there is a limit to its accuracy, and the effectiveness is not very high considering the number of people required. Therefore, the excavation depth is too deep and backfilling is required.
Alternatively, if the depth is too shallow, the work has to be re-excavated, which is inefficient and can lead to accidents such as digging too deep and destroying underground structures such as gas pipes. The major drawback was that it was easy to wake up.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a shovel vehicle that can excavate to a predetermined depth accurately and efficiently with as few personnel as possible.

The features of the shovel vehicle according to the present invention include: a first sensor that detects the vertical angle of the boom with respect to the swivel base; a second sensor that detects the angle of the arm with respect to the boom;
a third sensor that detects the angle of the bucket tote with respect to the arm; a fourth sensor that detects the length of the arm; and a vehicle body at the excavation edge of the bucket tort based on information from the first to fourth sensors. a calculation means for determining the vertical position of the hydraulic cylinder, a calculation display device for displaying the calculation result on the driving section, a means for setting the excavation limit depth, a means for detecting the driving direction of each of the hydraulic cylinders, and the driving direction detecting means. a determining means for identifying a hydraulic cylinder that is driving the bucket excavation edge in a downward direction from the detection results of the first to fourth sensors; and comparing a calculation result by the calculation means with a set value by the setting means. and a control means for stopping the driving of the hydraulic cylinder specified by the judgment means when the calculation result reaches a set depth.

According to the above characteristic configuration, the actual excavation depth is constantly displayed on the calculation display device, so the operator can easily and accurately know the current excavation depth by looking at the display device. Therefore, there is no operational difficulty or hassle of relying on visual estimation or intuition while taking into account changes in arm length.
In addition, it became possible to excavate to a predetermined depth accurately, easily, and extremely efficiently without the need for assistants, and this also prevented accidents such as destruction of gas pipes and water pipes. It is now possible to prevent this. Moreover, once the actual excavation depth reaches the preset excavation depth, the excavation will not be performed any deeper, thereby reliably preventing the above-mentioned accidents, and the hydraulic cylinder that drives the bucket excavation edge in the downward direction. By actively utilizing such a configuration in which only the drive of the excavator is stopped, there is an advantage that trenches or the like of a certain depth can be easily excavated in a short time.
For example, if the drive of all hydraulic cylinders is stopped based on reaching the excavation limit, the excavation work itself will have to be interrupted every time the excavation limit is reached, but according to the configuration of the present invention, the excavation operation itself will be interrupted every time the excavation limit is reached. Since the work can be continued as much as possible by driving the remaining hydraulic cylinder even after the excavation is completed, the number of interruptions is reduced, and as a result, there is an advantage that excavation of a trench or the like of a certain depth can be completed in a short time.

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

As shown in FIG. 1, a driving unit 3 and an operating cabin 4 are mounted on a swivel base 2 provided on a crawler type traveling device 1 so as to be freely rotatable around a vertical axis, and a hydraulic cylinder 18, a hydraulic cylinder 18, A backhoe device consisting of a boom 8, an arm 9, and a bucket 10, which can be driven and swung freely around a horizontal axis, is attached by 19 or 20 to form a backhoe work vehicle, which is an example of a shovel work vehicle.

The arm 9 itself is a hydraulic cylinder 21
It is configured to expand and contract.

Rotary encoders 12, 13, and 14 as first to third sensors are attached to the pivot shafts P1, _P2 , and _P3 of the boom ₈ , arm 9, and bucket 10, respectively. That is, the third
As shown in the figure, the first sensor 12 determines the vertical swing angle θ ₁ of the boom 8 with respect to the horizontal base line of the swivel base 2.
However, the boom 8 of the arm 9 is detected by the second sensor 13.
The configuration is such that the vertical swing angle θ ₂ relative to the arm 9 and the rotation angle θ ₃ of the bucket 10 relative to the arm 9 are detected by the third sensor 14 as digital numbers.

Furthermore, a rack gear 15 is fixed to the distal end arm portion 9a of the arm 9, which extends and contracts.
A pinion gear 17 equipped with a rotary encoder 16 as a fourth sensor is rotatably attached to the proximal arm portion 9b, and both gears 15 and 17 are disposed in mesh with each other.
Therefore, the rotary encoder 16 is driven as the arm extends and contracts, and the length _l2 of the arm 9 is thereby detected in digital numbers.

Next, based on FIG. 3, the principle of a method for calculating the position of the excavation edge _P4 of the bucket, which determines the excavation depth, will be explained based on the above angle and length information and other setting information.

That is, the length l ₁ of the boom 8 and the length of the bucket 10
l ₃ , and crawler traveling device 1 with boom 8 axis P ₁
The lower edge, ie, the height h from the ground, is given as a known number, while the angles θ ₁ , θ ₂ , θ ₃ are given as variable numbers.
and the length l ₂ of arm 9 is the first to fourth sensor 1
2, 13, 14, and 16, the position of the excavation edge of the bucket 10 can be determined using these numbers.
The depth d from the lower edge (ground) of the crawler traveling device 1 of _P4 is d = l ₁ sin θ ₁ + l ₂ sin (θ ₁ - θ ₂ ) + l ₃ sin (θ ₁ - θ ₂ - θ ₃ ) + h. It is expressed by the formula. The calculation of this equation is performed in a control calculation section 31, which will be described later.

FIG. 4 shows the configuration of the calculation and display system, which is configured to not only calculate and display the depth d of the excavation edge of the bucket 10, but also perform a safety function to prevent excessively deep excavation. In other words, if the excavation depth limit d ₀ is set, the excavation operation beyond this depth d ₀ is automatically stopped.

Hydraulic cylinder 1 for rotating the boom 8, arm 9, and bucket 10 around respective base axes P ₁ , P ₂ , and P ₃
8, 19, 20, and an oil passage connecting a hydraulic cylinder 21 that extends and contracts the arm 9 and a hydraulic pump 22 that sends pressure oil thereto.
3, 24, 25, 26 are provided, and
On the downstream side of these valves 23, 24, 25, and 26, electromagnetic valves 27, 28, 29, and 30 are provided, respectively, which shut off each oil passage based on the output current of the control calculation section 31. Furthermore, the operation valve 2
Three-value switches 32, 33, 34, and 35 are attached to the cylinders 3, 24, 25, and 26, respectively, as drive direction detection means for detecting the movement direction of each cylinder.

Reference numeral 31 denotes a calculation unit consisting of a microcomputer, which includes rotary encoders 12, 13, 14, 1 as the first to fourth sensors.
6 and the three-value switch 32, 33,
34 and 35 as well as the output of the depth setting device 38 for setting the lowering limit position d ₀ of the excavation edge of the bucket 10 are input, and the actual excavation depth d of the bucket 10 based on the formula (A) is inputted. Outputs the calculation result to the display 36 provided in the operating cabin 4, and controls the electromagnetic valves 27, 28, 29, 30 based on the comparison between the actual excavation depth d and the set depth _d0 . The excavation depth setting means, the calculation means, and the direction in which the excavation edge of the bucket 10 descends are configured to prevent excavation from occurring to a set depth _d0 or more. Judgment to specify which hydraulic cylinders 18, 19, 20, 21 are being driven; and hydraulic cylinders 18, 19, 20, 2
1 is provided with a control means for stopping the drive of the motor.

Next, details of the control configuration by this control calculation section 31 will be explained.

That is, the detection angles θ ₁ , θ ₂ , θ ₃ and the detection length
Based on l ₂ and the values of h, l ₁ and l ₃ given in advance, the actual excavation depth d is calculated using the above equation (A). Then, by comparing this actual excavation depth d and the set excavation depth d ₀ , when d substantially reaches d ₀ , one of the cylinders 18 , 19 , 20 , 21 is selected from the bucket at that point. Only the cylinder that is being driven to lower the tip of the cylinder 10 is stopped. However, if a direct configuration is adopted in which only that cylinder is stopped after determining which cylinder is driving the tip of the bucket 10 to descend, there is a risk that there will be a delay in the timing of the stop. Therefore, when d substantially reaches d ₀ , first all cylinders 18, 1
9, 20, and 21 are stopped, the above judgment is made, and then only the cylinder that was being driven to lower the tip of the bucket 10 is continued to be stopped, and the other cylinders are returned to their original state. We have adopted a phased structure for reinstatement. According to this configuration, once the excavation reaches the set depth, the movement of the backhoe is stopped immediately, and there is no need to excavate any deeper.
By automatically or manually re-driving one of the cylinders in the direction in which the tip _P4 of the bucket 10 rises, it is possible to quickly move on to the subsequent excavation work.

The judgment is made by each of the three-value switches 32, 33,
Each switching valve 23, 24, 2 by 34, 35
This is performed using the switching state detection results No. 5 and 26 and the angle detection results.

That is, the vertical movement direction of the base shaft P ₂ is uniquely determined by the rotational direction of the boom 8, and the relationship between the extension/contraction direction of the arm 9 and the vertical movement direction of P ₃ is also uniquely determined, so that regarding the cylinders 18 and 21, is determined only from the switching states of the switching valves 23 and 26. However, since the relationship between the operating states of the cylinders 19 and 20 and the vertical movement directions of the base shafts P ₃ and P ₄ is not necessarily determined only from the switching states of the switching valves 24 and 25, (θ ₁ −θ ₂ ) and (θ ₁ −θ ₂ −θ ₃ ) is also taken into consideration. This is the base P ₃
The relationship between the vertical movement direction of the switch valve 16 and the switching valve 16 is (θ ₁
This is because the situation is reversed when -θ ₂ )=-π/2 is reached, and the same holds true for the base axis P ₄ .

Next, specific signal processing in the control calculation section 31 will be explained using the flowchart shown in FIG.

Step (i) is the input mode of the excavation limit depth _d0 .

Control starts from step (ii), and in step (ii) the outputs θ ₁ , θ ₂ , θ ₃ , and l ₂ from the respective sensors 12, 13, 14, and 16 are read.

In step (iii), the depth d of the bucket tip P ₄ is calculated from θ ₁ , θ ₂ , θ ₃ , and l ₂ based on the excavation formula (A).

In step (iv), the calculated d is displayed on the display 36.
In step (v), it is checked whether the measured value d approaches the set value d ₀ with the error E or less, and if it does not approach, the process moves to step (ii) again where θ ₁ , θ ₂ , θ ₃ , l ₂ Measure.

When it is judged in step (vi) that the temperature is approaching E or below, all the electromagnetic valves 27, 28, 29, and 30 are shut off to shut off all oil passages and the movement of each part is stopped. After that, the oil passages other than those involved in the movement in the downward direction are returned to their original states in the following steps. Note that E is a constant determined in consideration of the time from the measurement of θ ₁ , θ ₂ , θ ₃ , and l ₂ until each part stops.

Step (vii) is related to the extension and contraction of arm 9.
If the operation valve 26 is in a state where the arm 9 is stopped or retracted in step (-), the electromagnetic valve 30 is opened in step (-). The state of this operation valve 26 is detected by a three-value switch 35.

Step (viii) concerns the movement of boom 8;
In step (-), it is checked from the signal of the three-value switch 32 provided on the operating valve 13 whether the boom 8 is being operated in the downward direction, and if not, in step (vi)-), the solenoid valve 27 is
It opens.

Step (ix) concerns arm 9, (-
), it is determined in which direction the arm 9 is rotated in the downward direction, and steps (-) and (-
), the switching valve 24 is in the position in each case.
It is checked whether P ₃ is operated in the downward direction, and if not, the solenoid valve 28 is opened. Step (x) is related to the bucket belt 10.
Perform the same process as (ix).

Step () waits for a certain period of time and then moves to step (ii) to measure θ ₁ , θ ₂ , θ ₃ , and l ₂ , and the movement is stopped many times by step (v). This is to prevent

In addition, in order to make d more accurate when the aircraft is tilted due to running aground on a raised part of the ground, it is necessary to adjust
The above-mentioned θ ₁ may be corrected based on the inclination in the front-rear direction. For this purpose, an angle detector may be provided to detect the inclination angle of the turning table 2.

That is, if the inclination angle of the turning table 2 is θ' (measured assuming that the slope in which P ₁ rises is positive), then θ ₁ in equation (A) above should be corrected to (θ ₁ + θ'). Bye.

The height h of P ₁ also varies somewhat due to the inclination of the aircraft, but its influence on d is smaller than the influence on d of angular variation, so this variation in h can be ignored.

When adopting a configuration that corrects the aircraft tilt angle, this can be done by reading the output θ' of the tilt angle detector in step (ii), and then correcting θ ₁ to (θ ₁ + θ'). The steps following step (iii) are exactly the same.

Although rotary encoders are used as the first to third sensors 12, 13, and 14 in the above embodiment for detecting angles, it is also possible to use potentiometers and A/D converters instead.

Further, as another embodiment of the device for detecting the arm length, as shown in FIG. It is also possible to configure the arm length to be detected by measuring the length.

Furthermore, by making some changes to the control program in the control calculation unit 21 in the above embodiment, in order to adapt it to cases where the height of the backhoe is limited, such as during excavation work in an orchard, for example, It may also be possible to perform height control.

The present invention can be applied to various types of backhoes, face shovels, etc., and the specific configuration of the target shovel vehicle can be changed freely.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of the drawing]

The drawings show an embodiment of a shovel work vehicle according to the present invention, and FIG. 1 is a side view of a backhoe work vehicle, and FIG.
The figure is a side view of the arm length detection mechanism, Figure 3 is a principle diagram of the excavation depth calculation method, Figure 4 is a configuration diagram of the calculation display system, and Figure 5 is a flowchart of signal processing.
FIG. 6 is a diagram showing another embodiment of the arm length detection device. 2...Rolling stand, 8...Boom, 9...Arm,
10...bucket, 12...first sensor, 13
...Second sensor, 14...Third sensor, 16
...Fourth sensor, θ ₁ , θ ₂ , θ ₃ ... Angle, l ₂ ...
Arm length, d... Required vertical position, d ₀ ...
Set vertical position, 32, 33, 34, 35... Drive direction detection means, 36... Arithmetic display device, 38...
Setting device.

Claims (1)

[Claims] 1 A boom 8 attached to the swivel base 2 so as to be able to freely swing up and down, an arm 9 that is extendable and retractable that is attached to the boom 8 so as to be able to swing up and down, and a bucket bucket that is attached to this arm 9 so that it can be pivoted up and down. 10 and hydraulic cylinders 18 to 21 for driving these, the first sensor 12 detects the vertical angle θ ₁ of the boom 8 with respect to the swivel base 2, and the first sensor 12 detects the vertical angle θ 1 of the boom 8 with respect to the boom 8. A second sensor 13 that detects the angle θ ₂ , a third sensor 14 that detects the angle θ ₃ of the bucket 10 with respect to the arm 9, and a length l ₂ of the arm 9
Based on the information from the fourth sensor 16 that detects and the first to fourth sensors 12 to 16,
A calculation means for determining the vertical position d of the excavation edge of the bucket 10 with respect to the vehicle body, a calculation display device 36 for displaying the calculation result on the driving section, a means for setting the excavation limit depth, and each of the hydraulic cylinders 18 to 21. The bucket 10 is determined from the driving direction detecting means 32 to 35 and the detection results of the driving direction detecting means 32 to 35 and the first to fourth sensors 12 to 16.
A judgment means for identifying the hydraulic cylinders 18 to 21 that are being driven in the direction in which the excavation edge is lowered, and a calculation result by the calculation means is compared with a set value by the setting means, and the calculation result reaches a set depth. and control means for stopping the driving of the hydraulic cylinder specified by the main judgment stage when the above-mentioned determination main stage has determined that the hydraulic cylinder is stopped.