JPS62291335A - Automatic excavation system of loading machine - Google Patents

Abstract

PURPOSE:To prevent the slip of tire when vehicular speeds are improper by a method in which a set value for starting control on a working machine is automatically corrected according to vehicular speed values detected by a sensor during the penetrating and excavating work period. CONSTITUTION:An angle sensor 2 for a bucket 1, an angle sensor 4 for a boom 3, a sensor to detect the oil pressure of a boom cylinder 5, a sensor to detect oil pressure of a bucket cylinder 7, and a sensor 9 for vehicular speed are provided. In a microcomputer in which detected values by each sensor are inputted, the driving of oil-pressure circuit is controlled on the basis of the horizontal and vertical components Rh and Rv of excavating resistance applying to the bucket 1 during excavation by using the detected values, and the set value is corrected according to vehicular speed V detected during the penetrating and traveling work period. The occurrence of slip of tire can thus be prevented, thereby lengthening the life of the tire.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] This invention is a loading machine such as a wheel loader, payloader or tractor excavator, in which a working machine actuator is controlled by a microcontroller according to the load. This invention relates to an automatic excavation method for a loading machine that enables efficient excavation work that does not depend on the driver's skill by controlling it overnight, and in particular relates to an improvement to suitably prevent tire slip on soft ground, etc. .

[Conventional technology]

Loading machines such as wheel loaders, payloaders, and tractor excavators that have booms and buckets as work equipment actuators are compact, have quick turns, and are inexpensive to purchase, making them ideal for civil engineering work sites, livestock farming, gardening, landscaping, and snow removal. It is used in a wide range of fields such as work.

In this type of loading machine, a boom cylinder rotates the boom up and down, and a bucket cylinder causes the bucket to perform tilt and dump operations, and these rotation operations of the boom and bucket move the earth and sand away. Carry out excavation and loading work.

By the way, the movement of the bucket in a wheel loader as described above is a combination of the movement of the suspension and the work equipment link, so it requires extremely high skill to move the bucket in the intended direction and perform digging operations efficiently. And for this reason,
Inexperienced drivers often push the bucket too far horizontally, creating excessive vertical resistance and lifting the rear of the vehicle, or raising the bucket too quickly and running out of excavated soil 2. There was a problem that work efficiency changed greatly depending on the situation.

Therefore, the inventors of the present invention have proposed the patent application No. 61-29526, 61-65181, or
The above problem was solved by the technology shown in No. These devices increase the load on the work equipment and control the work equipment actuator, that is, the boom and bucket, with a microcomputer according to the detected load, thereby allowing efficient work to be performed without relying on the skill of the operator. However, in these proposals, when automatic excavation starts, the boom and bucket are stopped at the initial position and the vehicle is driven through the vehicle, and when the horizontal excavation resistance exceeds a predetermined set value, the boom and bucket are stopped at the initial position. Boom drive control is started.

[Problem that the invention seeks to solve]

However, in this proposal, there is a delay between when the command to start control of the work equipment is issued and when the work equipment actually starts moving, so when the penetration speed is too fast, the vehicle body is slower than the movement of the work equipment such as the bucket and boom. The amount of movement is too large,
There is a problem in that tire slip occurs until sufficient downward resistance is applied due to the movement of the work equipment. In order to prevent this, if the setting value for starting the work machine control is made smaller, a problem arises in that the amount of soil excavated becomes smaller when the vehicle speed is slow.

[Means and effects for solving the problem] In order to solve the problem, the present invention provides a vehicle speed sensor for detecting vehicle speed, detects the vehicle speed during penetrating excavation by this vehicle speed sensor, and detects the detected vehicle speed. The set value for starting work machine control is automatically corrected according to the value.

〔Example〕

FIG. 2 shows an example of the external configuration of a wheel loader to which the present invention is applied. This wheel loader includes a bucket angle sensor 2 that detects the rotation angle θ1 of the bucket 1, and a bucket angle sensor 2 that detects the rotation angle θ2 of the boom 3. a boom angle sensor 4 that detects the hydraulic pressure Pa of the pressure oil supplied to the boom cylinder 5, a hydraulic pressure sensor 6 (not shown in FIG. 2) that detects the hydraulic pressure Pb of the pressure oil supplied to the bucket cylinder 7. Sensor 8 (
(not shown in FIG. 2), and a vehicle speed sensor 9 for detecting vehicle speed V.

Detection values θ1, θ2, P of these bucket angle sensor 2, boom angle sensor 4, oil pressure sensor 6.8, and vehicle speed sensor 9
a, Pb and V are input to the microcomputer 10 as shown in FIG.

The microcomputer 10 uses these detected values to determine the horizontal component R of the excavation resistance applied to the bucket 1 during excavation.
h and the vertical component Rv are calculated sequentially, and in the automatic excavation mode, the hydraulic circuit 2
0 drive control is performed, and a setting value correction, which will be described later, is performed in accordance with the vehicle speed value V detected during intrusion driving to prevent tire slip.

This hydraulic circuit 20 includes a boom control valve 21 that drives the boom cylinder 5, a bucket control valve 22 that drives the bucket cylinder 7, a tank 23,
Work equipment pump 24, pilot operating control (POC) pump 25, boom control valve 21
A normal ON/OFF valve consisting of a lift pilot valve 26 that controls the switching of the bucket control valve 22, and a tilt pilot valve 27 that controls the switching of the bucket control valve 22.
Switching valves 30 and 40, which are operated by switching signals S1 and S2 from the microcomputer 10, are added to the control type tandem circuit configuration. The switching valve 30 is arranged in the pilot pipe line from the lift pilot valve 26 to the upper lift spool 28 of the boom control valve 21, and when the switching signal S1 is not input, the switching valve 30 is connected to the pilot valve 26 and the upper lift spool 28. However, when the switching signal S1 is input, the POC pump 25 is directly connected to the upper lift spool 28. The switching valve 40 connects the tilt pilot valve 27 to the tilt side dump spool 2 of the bucket control valve 22.
9, and the switching signal S2
The pilot valve 27 and the tilt-side dump spool 29 are connected when the pump is not operated, but when the switching signal S2 is input, the POC pump 25 is directly connected to the tilt-side dump spool 29. These switching signals S1 and S2 are manually input from the microcomputer-0 when the automatic excavation mode is designated by turning on the switch 11.

Before explaining the automatic excavation operation according to the configuration of this embodiment, an example of a method for deriving the horizontal resistance Rh and the vertical resistance Rv will be explained with reference to FIGS. 3 and 4.

In this method, the input information is bucket rotation angle θ1,
Using the boom rotation angle θ2, the oil pressure Pa of the pressure oil supplied to the boom cylinder 5, and the oil pressure pb of the pressure oil supplied to the bucket cylinder 7, 1. Using these detected values, horizontal resistance Rh and vertical resistance Rv are derived.

Now, if the cross-sectional areas of the boom cylinder 5 and bucket cylinder 7 are Sa and Sb, respectively, then each cylinder 5 and 7
The cylinder forces Fa and Fb are Fa −Pa −Sa
−= (1) Fb −Pb −Sb
...(2).

Here, it is assumed that the resistance application point PD (XD, YD) changes as shown in FIG. 4 in response to the rotation of the bucket 1 (rotation angle θ1). In the graph shown in FIG. 4, the vertical axis is the distance DLS between the tip point of the bottom plate of the bucket and the point of resistance PD, and the horizontal axis is the bucket rotation angle θ1, and θh
(fixed value) is the angle at which the side edge 1a of the bucket 1 becomes horizontal, and Lc is the length of the side edge 1a.

Here, considering the X-Y coordinates centered on the bin Pa, the coordinates of the bin P1 before the bucket 1 is rotated are (X1'
, Y1'), then the coordinates (X, , Yl) of Pl after the boom 3 rotates by θ2 are, and the illustrated distance between the bucket bin P1 and the tip point of the bucket bottom plate is gl, and the side edge of the bucket bottom plate and the bottom plate are If the angle formed with
D=X++Ω1CO8θ1−DLcosψ...(4)
YD=Y1+Ω1 sinθ1−DLsinψ−(5
), and based on the graph in FIG. 4, θ1. The coordinates of PD after θ2 rotation can be specified.

Now, the dimensions shown in Figure 3 are L+, L2°L3.
L4. L5 and considering the balance of moments around the bottle PO, Rv-XD+Rh-YD-Fa-L4 F b' L 5-0...(6
), and if we consider the balance of the moments for the bottle P1, RV ・ (XD + X+ ) −R
h Conflict (Y+ -YD) -Fb'L3
−0...(7). Since also holds true, Rh and Rv can be obtained by solving these equations (6), (7), and (8).

Next, the automatic excavation operation according to the configuration of this embodiment will be explained with reference to the flowchart shown in FIG.

In this embodiment, four set values Rhl, Rh2, . Set Rhu and Rhd. Among these set values, Rhl is used to determine the time to start excavation, and is set to a value of about 500 to 1000 kg for an 8-ton class wheel loader. Further, Rh2 is used to determine the start point of work equipment control, and this value is determined by the vehicle speed value V as described later.
It is variable depending on.

Furthermore, Rhu and RM are the upper and lower limit set values used after work equipment control is started, and Rhu determines the transition point from boom drive to bucket drive, and R
hd determines the transition point from bucket drive to boom drive. Regarding the vertical resistance Rv, a set value Rvs as shown in FIG. 6 is set. In other words, when considering the moment around the front wheel due to the vertical resistance Rv, the vertical resistance setting value Rvs is calculated based on the fact that the horizontal component of the distance from the front wheel to the center of gravity of the bucket changes as the boom 3 rotates. In order to keep the moment around the front wheel due to the vertical resistance Rv constant, it is changed as shown in FIG. In the figure, ya is the setting value of the excavation end pin height.

Now, when performing automatic excavation, the operator turns on the automatic excavation mode switch 11, starts the engine,
For example, the gear is set to first speed and the vehicle is driven against the embankment (step 100). During this initial excavation stage,
Horizontal penetration (penetrating travel) excavation is performed by driving the vehicle with the boom 3 and batt 1 stopped at their initial positions. When the microcomputer 10 detects the turning on of the switch 11, the microcomputer 10 detects each detected value θ1 of the bucket angle sensor 2, the boom angle sensor 4, the oil pressure sensor 6, and the oil pressure sensor 8.
．． θ2. Pa and pb are taken in, and using these detected values, horizontal resistance Rh and vertical resistance Rv are calculated according to the method explained in FIGS. 3 and 4 (step 102). Then, the microcomputer 10 compares the calculated horizontal resistance Rh with the set value Rhl in step 10.
4) When the horizontal resistance Rh exceeds the set value Rhl, this is regarded as the time to start excavation control, and the process moves to the next process.

Next, the microcomputer 10 takes in the detected value V of the vehicle speed sensor 9 and calculates the set value Rh2 based on the detected value V (step 106). For example, in an 8-ton class wheel loader, the setting value Rh2 is calculated based on the following arithmetic expression.

Rh2-2500 Next, the microcomputer 10 calculates the horizontal resistance Rh and vertical resistance Rv again (step 108), and compares the calculated horizontal resistance Rh with the set value Rhl (step 11).
0), if the horizontal resistance Rh exceeds the set value Rhl, the process moves to step 120;
If the horizontal resistance Rh is less than the set value Rhl, the process returns to step 102 and steps 104, 106, and 108 are executed again. The reason for adding step 110 above is to deal with the case where the horizontal resistance increases temporarily due to the butt hitting gravel, and if the horizontal resistance increases temporarily due to hitting the gravel. , the comparison result in step 104 is rYEsj, but the second comparison result in step 110 is rNOJ, R
By comparing h and Rhl twice at different times, it is possible to prevent the excavation control start point from being erroneously detected.

In parallel with the above-mentioned processing, the horizontal resistance Rh is calculated as shown in Fig. 7 (
As shown in 1), it gradually increases and eventually exceeds the set value Rh2. The microcomputer 10 determines the horizontal resistance Rh and set value R in step 120.
When it is detected that Rh>Rh2 by comparison with h2, the work machine control is started at the time of this detection (step 125).

As described above, in this embodiment, the setting value Rh2 for starting the work machine control is varied according to the vehicle speed value V during penetrating excavation,
Since the work equipment control start point is determined based on the comparison result between the variable set value Rh2 and the horizontal resistance Rh,
Changes depending on the start point of work equipment control or the vehicle speed value 1
4, thereby making it possible to accurately prevent tire slippage due to a delay in starting control of the work equipment when the vehicle speed is inappropriate, and to extend the life of the tires.

Next, the work machine control procedure after step 125 will be explained.

With the start of work machine control, the microcomputer 10 first outputs a switching signal S2 to switch the switching valve 40, thereby sending the hydraulic pressure of the POC pump 25 to the tilt side spool 29 of the bucket control valve 22,
The bucket cylinder 7 is driven to the tilt side to start tilting the bucket 1 (step 130).

As a result, the horizontal resistance Rh decreases as shown in FIG. 7(n).

Next, the microcomputer 10 again selects the horizontal resistance Rh.
and vertical resistance Rv (Step 140), unless the stroke end of the bucket cylinder 7 is detected (
Step 150), this time the calculated vertical resistance Rv is compared with the vertical resistance setting value Rvs shown in FIG.
If sRvs, the horizontal resistance R calculated above is further
h is compared with the lower limit set value Rhd of the horizontal resistance (step 170). As a result of this comparison, if the horizontal resistance Rh is greater than the lower limit set value Rhd (Rh>Rhd),
The microcomputer 10 continues the switching and sending of the signal S2, and further tilts the bucket 1 (step 130). From now on, RvsRvs and Rv>Rhd
As long as the microcomputer 10 receives the switching signal S2
continues to send out and tilts bucket 1 further.

However, as a result of the comparison in step 170, if the horizontal resistance Rh becomes smaller than the lower limit set value Rhd, the microcomputer 10 stops sending out the switching signal S2, temporarily stops the tilting movement of the bucket 1, and then switches Switching the switching valve 30 by outputting the signal S1,
The hydraulic pressure of the POC pump 25 is controlled by the boom control valve 2.
1 to the upper spool 28 of 1, and drives the boom cylinder 5 upward (a) to raise the boom 3 (step 180).As the boom rises, the horizontal resistance Rh is now reduced to the figure M7. It tends to increase as shown in (III).

Next, the microcomputer 10 again selects the horizontal resistance Rh.
, Rv is calculated (step 190), and unless the boom angle θ1 exceeds a predetermined set angle (step 200), the calculated vertical resistance Rv is then compared with the set value Rvs (step 210), and Rv>Rvs is not satisfied. In this case, the horizontal resistance Rh calculated above is further set as the upper limit setting value R of the horizontal resistance.
hu (step 220). As a result of this comparison, if the horizontal resistance Rh is less than the upper limit set value Rhu (Rh:i;Rhu), the microcomputer 10 first compares this horizontal resistance Rh with the previously calculated horizontal resistance value Rhp. (Step 230). If the result of this comparison is Rh≧Rhp, the microcomputer 10 continues to send out the switching signal S1,
The boom 3 is further raised (step 180). And from now on, microcomputer E0 is RvsR
vs, Rh≦Rhu.

Continue sending the switching signal S1 as long as Rh≧Rhp,
Raise and rotate boom 3.

Then, the microcomputer 10 performs step 220
When the result of the comparison in is Rh>Rhu, that is, when the horizontal resistance Rh exceeds the upper limit setting value Rhu,
The sending of the switching signal S1 is stopped to stop the upward movement of the boom 3, and the switching signal S2 is outputted to restart the tilting movement of the bucket 1 (step 130).
. Due to the tilt movement of the bucket, the horizontal resistance Rh becomes 7th.
As shown in Figure (IV), it descends again.

In addition, the microcomputer 10 determines that when the horizontal resistance Rh becomes smaller than the previous horizontal resistance calculation value Rhp during the ascent of the boom 3 described above (Rh <Rhp).
, similarly to the above, the transmission of the switching signal S1 is stopped to temporarily stop the upward movement of the boom 3, and this time, the switching signal S2 is stopped.
is output to tilt bucket 1 (
Step 130). That is, while the boom is being driven upward, the horizontal resistance Rh is equal to the upper limit set value Rhυ of the horizontal resistance.
In this case, the boom continues to be raised while the horizontal excavation resistance Rh due to the load is insufficient. Therefore, while the boom is rising, in step 230, the current horizontal resistance value Rh is
A fall in the horizontal resistance Rh is detected by comparing it with the horizontal resistance value Rhp calculated just before, and if the fall is detected, the upward movement of the boom is stopped as shown in Figure 7 (V). By tilting the bucket, the horizontal resistance value R
h is forcibly lowered to the lower limit set value Rhd, and then the boom is raised again to increase the horizontal resistance value Rh to the upper limit set value Rhu.

In this way, the horizontal resistance Rh reciprocates between the upper limit set value Rhu and the lower limit set value Rhd by alternately repeating the raising drive of the boom and the tilting drive of the bucket. While performing such switching drive, the vertical resistance R
When v becomes larger than the set value Rvs, the microcomputer 10 detects this in step 160 or step 210, and then moves the procedure to step 240. That is, if RV>RVS is detected in step 160, the microcomputer 10 continues sending out the switching signal S2, thereby changing the procedure to step 2.
40, and if Rv>Rvs is detected in step 210, the transmission of the switching signal S1 is stopped and the switching signal S2 is output, and the procedure returns to step 24.
0.

Thereafter, the microcomputer 10 continues to output the switching signal S2 until the end of the predetermined excavation, thereby tilting the bucket 1 by a predetermined angle, and then ends the current excavation operation (step 250). In addition, methods for detecting the end of excavation include a method in which the time when the sand ridge 1a of the bucket 1 becomes horizontal is the time when the end of digging is determined, and a method in which a method in which the time when the ground height of the bucket pin P1 reaches a predetermined height is the time when the end of excavation is determined. , a method of detecting the stroke end of a bucket shilling, etc.

Next, FIG. 8 shows another example of a structure for preventing slipping.

In the configuration example shown in FIG. 8, a pedal range regulating device 51 is provided that regulates the pedal range of the accelerator pedal 50 that controls the fuel injection amount of the engine. This stepping distance regulating device 51 has a stopper 52 that protrudes during penetrating travel to restrict the stepping distance, and this stopper 52 prevents the accelerator pedal 50 from being fully depressed. . This stopper 52 is driven to protrude and return by a structure consisting of, for example, a solenoid and a spring.

Generally, the traction characteristics of a wheel loader are as shown in FIG. 9 (I) when the gear is fixed and the accelerator is fully pressed, and when the accelerator pedal 5o is released by the stopper 52, the maximum traction is Force (vehicle speed zero)
Fm decreases to <FlIl' as shown in Figure (II).

In addition, in a general wheel loader, when the gear is in 1st gear and the accelerator is fully pressed, the relationship is approximately the maximum traction force Fm - vehicle weight (w) x O19, and in this case,
Maximum traction force Fan' after stopper regulation is 60 of vehicle weight W
The protrusion height of the stopper 52 is preferably set within a range of 70%.

Hereinafter, the specific operation of the configuration example will be explained according to FIGS. 10 and 11. Note that the flowchart shown in FIG. 11 corresponds to the flowchart shown in FIG.
Steps 50 and subsequent steps are the same as steps 125 and subsequent steps in FIG. 5, so the explanation thereof will be omitted.

When the vehicle starts running (step 300), the microcomputer 10 calculates the horizontal resistance Rh and the vertical resistance Rv in the same manner as described above (step 310).
), the stopper 52 of the stepping distance regulating device 51 is immediately projected (step 320). As a result, the amount of depression of the accelerator pedal 50 is regulated, and the driver can press the accelerator pedal 50.
Even if the vehicle is fully stepped on, the maximum traction force of the vehicle is 6 times the vehicle weight.
The maximum traction force is approximately 0 to 70%, and horizontal penetration excavation is performed with this maximum traction force. Then, penetration excavation is performed with the stopper 52 protruding until the horizontal resistance Rh exceeds the set value Rh2 for starting the work machine control (Fig. 10, period T
]). Through such processing, the horizontal resistance Rh gradually increases and then exceeds the set value Rh2. If the microcomputer 10 detects Rh>Rh2 through the comparison in step 330, it immediately closes the stopper 52.
is returned from the protruding position to its original position (step 340), and the calculated horizontal resistance Rh and vertical resistance R are
The above-mentioned work equipment control to drive and control the bucket 1 and boom 3 is started based on v (step 350), and then, after going through the steps from step 125 in FIG. 5, the excavation operation is ended (period T2 in FIG. 10). .

In this manner, in this configuration, by regulating the depression distance of the accelerator pedal 50 by the stopper 52,
The maximum traction force during penetration driving was reduced to about 60-70% of the vehicle weight, and then the pedal clearance regulation was canceled when work equipment control was started, so the amount of accelerator pedal depression during penetration driving was reduced. It is possible to accurately prevent tire slip that occurs due to a delay in starting the working machine if the amount is too large.

In this configuration example, the fuel adjustment pedal 50 is connected to the stopper 5.
However, in the case of a loading machine equipped with a fuel adjusting lever, the displacement amount of the lever can be regulated by an appropriate displacement amount regulating means, and the same structure as the above example can be used. Just try to get results.

Next, FIG. 12 shows another example of a structure for preventing slipping.

In this configuration example, during penetration travel, the electronic governor is
+ control, the maximum traction force during penetration driving was made to be about 60 to 70% of the vehicle weight W.

In FIG. 12, the throttle amount of the accelerator pedal 50 is detected by a throttle amount sensor 60, and the throttle amount sensor 60 inputs a target engine speed corresponding to the detected value to a changeover switch 62. Further, the set value generating means 51 stores a target engine speed at which the maximum traction force becomes a predetermined value within the range of 60 to 70% of the vehicle weight W.
This target engine rotation speed is set in advance based on the relationship shown in the figure, and this target engine rotation speed is input to the changeover switch 62. The changeover switch 62 switches the input signal according to the changeover signal SL input from the microcomputer 10.
Based on the switching signal SL, either of the two input target engine speeds is manually input to the addition point 63. Additional points 63
The detection signal of the engine rotation speed sensor 67 is input as a feedback signal, and the addition point 63 calculates the deviation of these deviations and inputs the deviation to the drive circuit 64.

The drive circuit 64 drives the injection amount adjustment rack 66 so that the input deviation becomes zero, thereby increasing or decreasing the fuel injection amount of the engine 65.

In such a configuration, when the automatic excavation mode is specified and the vehicle starts running (step 400 in FIG. 13), the microcomputer 10 adjusts the horizontal resistance Rh in the same manner as described above.
and vertical resistance Rv (step 41).
0), by immediately inputting the switching signal SL to the changeover switch 62, the contact is switched to the set value generation means 61 side. As a result, an engine rotation speed command is manually input to the addition point 63 from the set value generation means 61 as a target value so that the maximum traction force of the vehicle becomes a predetermined value within the range of 60 to 7096 of the vehicle weight W, and the drive circuit 64 performs feedback control using the engine speed as a target value (step 4).
20). This feedback control is continued until the horizontal resistance Rh exceeds the work control start set value Rh2. After that, if the horizontal resistance Rh increases and exceeds the set value Rh2, the microcomputer 10 performs step 43.
This is detected by comparing 0 and the selector switch 62 is immediately turned on.
The contact is switched from the set value generating means 61 side to the throttle amount sensor 60 side. As a result, the engine rotational speed corresponding to the detection output of the throttle amount sensor 60 can be input to the addition point 63 as a target value (step 440). Immediately after canceling the governor control in this way, the microcomputer 10 starts the aforementioned work machine control for driving the bucket 1 and the boom 3 (step 450).
. Thereafter, the excavation operation is completed after going through the steps starting from step 125 in FIG.

In this configuration example, the electronic governor is controlled so that the maximum traction force of the vehicle is 60 to 70% of the vehicle weight W during penetrating excavation. It is possible to accurately prevent tire slips that occur.

In addition, in the present invention, the horizontal resistance Rh and the vertical resistance RV
The calculation method for determining is not limited to the method explained using FIG. 3 and FIG.
Rh and Rv may be determined based on the force balance between the detected value and the horizontal and vertical resistances Rh and Rv.

Furthermore, the method of driving the bucket and boom is not limited to that shown in the above embodiments, but may also be used, for example, in Japanese Patent Application No. 61-29
526 or Japanese Patent Application No. 61-65181 may be used.

Furthermore, the loading machine to which the present invention is applied is not limited to wheel loaders, but may also include payloaders, tractor excavators, etc.
It is applicable to all machines that use booms and buckets as work equipment actuators.

〔Effect of the invention〕

As explained above, according to the present invention, the vehicle speed during penetrating excavation is detected, and the set value for starting control of the work equipment is automatically corrected according to the detected vehicle speed value, so that when the vehicle speed is not appropriate, the vehicle speed is detected. It is possible to prevent tire slippage that occurs due to a delay in starting the work equipment, thereby extending the life of the tires.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of the overall control configuration of an embodiment of the present invention, FIG. 2 is a side view showing the external configuration of a wheel loader and an example of arrangement of each sensor, and FIG. 3 is a horizontal/vertical resistance resistance diagram. A diagram for explaining an example of calculation for determining Rh and Rv, Fig. 4 is a graph showing an example of a set movement locus of the resistance application point used in the calculation example, and Fig. 5 is a concrete example of the operation of the same example. A flowchart showing the vertical resistance setting value Rv is shown in FIG.
7 is a graph showing the relationship between s and bucket height y, FIG. 7 is a diagram showing an example of change in horizontal resistance according to this embodiment, FIG. 8 is a conceptual diagram showing another example of a slip prevention structure, and FIG. A graph showing the relationship between traction force and vehicle speed, Fig. 10 is a diagram showing an example of how the accelerator opening changes over time with the same configuration example, Fig. 11 is a flowchart showing a concrete example of the operation of the same configuration example, and Fig. 12 is a slip chart. A block diagram showing yet another configuration example for prevention,
FIG. 13 is a flowchart showing a specific example of the operation of the same configuration example. 1...Bucket, 2...Bucket angle sensor, 3...
- Boom, 4... Boom angle sensor, 5... Boom cylinder, 6.8... Oil pressure sensor, 7... Bucket cylinder, 9... Vehicle speed sensor, 10... Microcomputer, 11.・・Automatic excavation switch, 20・Hydraulic circuit, 21・Boom control valve, 22・
... Bucket control valve, 23... Tank,
24... Work equipment pump, 25... POC pump, 2
6... Pilot valve for lift, 27... Pilot valve for tilt, 28° 29... Spool, 30.40.
...Switching valve. 50... Accelerator, 52... Stopper, 60... Throttle amount sensor, 61... Set value generating means, 62... Changeover switch, 63... Addition point,
64... Drive circuit, 65... Engine, 66...
Rack, 67...Engine speed sensor. --= Figure 2 Figure 3 he1 Figure 4 Figure 6 Same amount Figure 7 Figure 12 Figure 13

Claims (1)

[Claims] A method for sequentially detecting horizontal and vertical components of excavation resistance applied to a bucket of a loading machine having a boom and a bucket,
The boom and the bucket are automatically driven and controlled in accordance with the detected horizontal excavation resistance and vertical excavation resistance from the time when the detected horizontal excavation resistance exceeds a predetermined set value after the loading machine is running. The automatic excavation method for a loading machine that performs excavation is characterized in that a vehicle speed sensor is provided to detect the vehicle speed of the loading machine, and the set value is automatically corrected in accordance with the output of the vehicle speed sensor. Automatic digging method for loading machines.