JPH0542122Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a control device for a boom-type working machine.

(Prior art) A front loader, which is attached to a tractor body and performs work, has a boom pivotably supported on the tractor body so that it can be raised and lowered, and a bucket rotatably attached to the tip of the boom. A solenoid valve corresponding to each cylinder is installed in the hydraulic circuit of the boom cylinder and bucket cylinder that operate the boom cylinder, and this solenoid valve controls the raising and lowering of the boom, the scooping of the bucket, and the rotation in the dumping direction. ing.

Conventionally, the control device for this type of work machine has one
Generally, a switch is operated by moving the operating lever of a book back and forth or left and right, and this switch turns a solenoid valve on and off.

(Problem that the invention aims to solve) The attitude of the bucket side when the boom is raised and lowered is
This is determined depending on the purpose of the work; for example, the boom may be raised while the opening of the bucket is kept horizontal, or the boom may be lowered while the bottom of the bucket is kept horizontal. In such cases, the conventional method was to control the work tool in a predetermined position by manipulating a single operating lever in a complex manner, which had the disadvantage of requiring a high level of skill to operate. .

(Means for Solving the Problems) The present invention aims to solve the problems of the conventional art, and as a specific means for that purpose, it is a device that is pivoted to the vehicle body 1 so that it can be raised and lowered. In a boom work machine equipped with a boom 10 and a work implement 13 rotatably supported on the boom 10, the work implement control system is configured to maintain a required posture of the work implement 13 when the boom is raised. a rising mode setting section 71 for setting a working mode for controlling the posture of the working tool 13;
the work tool 13 so as to maintain the required posture.
A lowering mode setting section 72 is provided to set a work mode for controlling the posture of the boom, and the raising mode setting section 71 is selected when the boom is raised by a lift signal of the boom control system that controls the raising and lowering of the boom, and when the boom is lowered, the lowering mode setting part 71 is selected. Mode switching means 76 and 77 for selecting a descending mode setting section 72 are provided.

(Function) [] Manual control For manual control, use the manual/automatic changeover switch 8.
1 to the manual side and then operate the control lever 26. By operating the control lever 26 in the direction of the arrow shown in FIG. 7, the boom 10 can be raised or lowered, the bucket 13 can be dumped, It is possible to perform scooping and complex operations that combine these operations (see Figure 10). Note that when the operating lever 26 is released, it automatically returns to the central stop position.

Now, when the operating lever 26 is rotated toward the rear rising side, the first potentiometer 27 is actuated via the horizontal shaft 30, and the resistance value changes according to the amount of operation, and the voltage of the command signal is becomes large. here,
At the stop point where the operating lever 26 is at the neutral stop position, the resistance value of the first potentiometer 27 becomes 1/2.
It is assumed that the voltage at that time is 1/2 of the supply voltage V. This is called the neutral point. When the command signal from the first potentiometer 27 is sent to the comparison sections 46 and 47 of the first discrimination means 45, since it is larger than the neutral point, the comparison section 46 discriminates it as a rise command and outputs a rise signal. The analog switch 63 of the first driving means 60 is turned on. On the other hand, the command signal from the first potentiometer 27 is input to each comparing section 55, 56 of the first comparing means 54, and is compared with the triangular wave signal from the triangular wave oscillating means 53. In this case, since the command signal is larger than the neutral point, the comparison section 55 of the first comparison means 54 compares the two, and turns on when the command signal is larger than the triangular wave signal as shown in FIG. A pulse signal is generated by the comparator 55. and,
The larger the deviation between the two, the wider the pulse width of the pulse signal becomes.
The on/off operation is repeated by the pulse signal of
Excitation current flows intermittently to the ascending solenoid 40 of the first electromagnetic valve 39 . As a result, the rising solenoid 4
0 repeats excitation and demagnetization in synchronization with the pulse signal, the first solenoid valve 39 switches to the upward side with an opening proportional to the excitation and demagnetization, and the boom cylinder 11 moves in the extension direction at a predetermined speed, causing the boom 10 to move. Raise it around axis 9. Therefore, by changing the amount of operation of the operation lever 26, the opening degree of the first solenoid valve 39 changes, and the flow rate to the boom cylinder 11 changes, so that the flow rate changes proportionally according to the amount of operation of the operation lever 26. The boom 10 rises at a certain speed, and can be controlled at any speed from high speed to slow speed. Then, when the operating lever 26 is returned to the neutral stop position, the first solenoid valve 39 returns to the neutral position, and the boom 10 stops at the raised position. At this time as well, if the operating lever 26 is gradually returned, the boom 10 will come to a slow and smooth stop.

This is the same when operating the operating lever 26 forward to lower the boom 10, and when operating the operating lever 26 left and right to cause the bucket 13 to perform a dumping or scooping operation.

When the operating lever 26 is operated as much as possible in the front, rear, left, and right directions, the switches 34 to 37 are operated by the operating section 33, and the corresponding solenoids 40, 41, and 4 are activated.
Since current flows through solenoid valves 39 and 42,
works. This allows the solenoid valves 39, 42 to be operated without going through the control system. However, in this case, proportional control is not possible, and therefore, it is only necessary to use it in the event of a failure.

[] Automatic control For automatic control, use the manual/automatic changeover switch 8.
1 to the automatic side, select and set the mode of the bucket tot 13 when going up and down with the switches 74 and 75, and the bucket tot 13 will maintain the target posture just by operating the control lever 26 back and forth. While doing so, the boom 10 moves up and down. Note that the operation of the boom control system is the same as described above.

In this case, the attitude sensor 16 that detects the attitude of the bucket 13 is used, but the relationship between the attitude sensor 16 and the attitude of the bucket during scooping, horizontal elevation of the opening surface, horizontal elevation of the bottom surface, and dumping is as shown in FIG.
It will look like D. Further, the relationship between the posture sensor 16 and the voltage when the bottom surface is horizontally raised and lowered and the opening surface is horizontally raised and lowered is as shown in FIG.

Below, each operation will be described in the order of keeping the opening surface horizontal and maintaining its posture when the boom is raised, and keeping the bottom surface horizontal and in contact with the bottom when the boom is lowered.

Rising when the aperture surface is horizontal Set the switch 74 of the rise mode setting section 71 to the aperture surface horizontal position to select the aperture surface horizontal voltage Vr ₂ . Here, when the opening surface of the bucket 13 is parallel to the horizontal line, the voltage (resistance) of the attitude sensor 16 is always constant and is independent of the attitude of the boom 10 and the attitude of the tractor body 1. Therefore, the potentiometer in the rising mode setting section 71 is set as shown in FIG. 12 so that the voltage at this time becomes the aperture horizontal voltage _Vr2 .

If the switch 74 is placed on the horizontal side of the opening surface,
When the operation lever 26 is operated to the upward side, the analog switch 7 is activated by the upward signal from the comparator 46.
6 is turned on, the voltage Vr ₂ is sent to the inverter 78 via the analog switch 76, and this voltage Vr ₂ is inverted by the inverter 78 around the 1/2V voltage at the N terminal to become the voltage Vr ₂ '. Then, this voltage Vr ₂ ' and the detected voltage from the attitude sensor 16, that is, the voltage indicating the current attitude of the bucket bag 13, are detected by the deviation detection means 79.
After calculating the deviation of both voltages, the inverting section 8
Invert and amplify at 0. These characteristics are shown in Figure 14A.
- Shown in C.

Therefore, if the voltage of the attitude sensor 16 indicates the voltage Vr ₂ , the deviation becomes 0, and there is no need to correct the attitude of the bucket 13, so the subsequent stage side does not operate.
Further, if the attitude sensor 16 is rotated toward the dump side than the opening surface is horizontal, the voltage of the attitude sensor 16 is large, so the deviation voltage of the deviation detection means 79 is the 14th
The state shown in Figure C is reached, and the voltage is below the neutral point. Then, based on this deviation voltage, the second determining means 49 judges that the rake direction needs to be corrected, and the second comparing means 57 compares the deviation voltage with the triangular wave signal, A pulse signal with a pulse width is generated, and the scoop solenoid 44 of the second electromagnetic valve 42 is energized via the analog switch 69 and switching element 67 of the second driving means 65, and the bucket cylinder 14 is contracted. Correct it in the scooping direction. Bucket 1
3 approaches the opening surface horizontally, the attitude sensor 1
Since the voltage at 6 becomes smaller, the deviation voltage gradually becomes smaller and the pulse width of the pulse signal becomes smaller, so the operating speed of the bucket cylinder 14 becomes slower and the correction operation stops when the deviation becomes 0. That is, the closer the opening surface is to the horizontal, the slower the operating speed of the bucket 13 becomes, and the operation speeds up and stops smoothly.

Conversely, if the bucket 13 is on the rake side, the deviation voltage will be in the state shown in FIG. 14C, so the bucket 13 moves in the dumping direction and corrects the opening surface to be horizontal.

Therefore, the boom 10 rises while the bucket 13 maintains the opening surface in a horizontal state.

Raise to maintain posture Scoop compost etc. into bucket 13 and raise boom 1
0, if the bucket 13 is not held in the state it was in when scooping, there is a risk that the compost in the bucket 13 will spill out or fall onto the operator side due to the force of the lift. Therefore, in such a case, it is necessary to raise and lower the bucket 13 while holding it in the scooping position.

Therefore, at this time, the switch 74 is set to the posture holding side, and the holding switch 32 is turned on. Then, the voltage indicating the current attitude of the bucket 13 is input to the sample/hold section 73 and held for a certain period of time, so this held voltage is input to the inverting section 7
8, and the deviation detection means 80 detects the attitude sensor 16.
Find the deviation from the voltage and invert it. and,
Using the deviation voltage, the attitude of the bucket bag 13 is controlled in the same manner as the bottom horizontal control and opening surface horizontal control described above. Therefore, even if the boom 10 rises, the bucket 13 will maintain its initial position.

Falling with the bottom _horizontal The bucket 13 is lowered while being controlled so that the bottom surface is horizontal in the same manner as described above.

The operating characteristics at this time are as shown in FIGS. 13A to 13C.

Descending with bottom ground control Bottom ground means that the bottom surface of the bucket 13 is on the same plane or parallel to the plane on which the front and rear wheels 2 and 3 of the tractor body 1 are on the ground, or parallel to it, as shown in FIG. 15A. Refers to the condition. This is used when lowering the bucket 13 onto the ground or scooping it along the ground surface. In particular, when the bucket truck 13 is grounded, it is difficult for the operator in the driver's seat 5 to see the attitude of the bucket truck 13 because it is obstructed by the bonnet, so this is very convenient in such a case.

The major difference between bottom ground control and other controls such as bottom horizontal control is that in other controls, control is based on the deviation of the rotation angle of bucket 13 from the direction of the center of gravity; In addition to the posture, a new factor such as the inclination of the tractor body 1 is added.

Therefore, the tilt sensor 15 is used for control. In this case, as shown in FIG. 15B, the bucket 13
The signal voltage (resistance) of the tilt sensor 15 and the attitude sensor 16 are set to be the same when the bottom surface of the sensor is grounded.

For control, switch 75 is placed on the side of inclination sensor 15 on the bottom surface. Then the tractor body 1
If there is an inclination, the inclination sensor 15 detects the inclination, and the voltage changes. At this time, Bucket 1
3 are on the same ground surface, the attitude sensor 16 also has the same signal voltage as the tilt sensor 15. but,
If the voltages of the attitude sensor 16 are different, the bucket cylinder 14 is activated to correct the attitude of the bucket 13 so as to bring it into contact with the bottom surface by the same operation as the bottom horizontal control described above.

(Embodiment) The present invention will be described in detail below with reference to the illustrated embodiment. In FIG. 2, 1 is a tractor body, 2 is a front wheel, 3 is a rear wheel, 4 is a rear wheel fender, and 5 is a driver's seat. Reference numeral 6 designates a front loader, which includes a mast 8 that is removably installed on both sides of the tractor body 1 via a mounting base 7, a boom 10 that is pivoted to the upper end of the mast 8 with a pivot 9 so that it can be raised and lowered, and A boom cylinder 11 for raising and lowering the boom 10, and a boom 1
1, and a bucket cylinder 14 for rotating the bucket 13.

Reference numeral 15 denotes an inclination sensor for detecting the inclination of the tractor body 1, which is attached to the front loader 6 side, for example, the mast 8. Reference numeral 16 denotes an attitude sensor for detecting the rotating attitude of the bucket cart 13, which is attached to a bracket 17 on the back side of the bucket cart 13. These sensors 15 and 16 are constructed by incorporating a weight plate 21 and a potentiometer 22 into two divided chambers 19 and 20 within a box-shaped case 18, as shown in FIG. The weight plate 21 is attached to a rotating shaft 23 supported by the case 18, and the potentiometer 22 is configured to be interlocked with the weight plate 21 via the rotating shaft 23. The weight plate 21 responds to changes in the attitude of the bucket 13, and a voltage signal corresponding to the attitude is output from the potentiometer 22. In addition, room 19
Damper oil 23a is placed inside.

Reference numeral 24 denotes an operating device, and as shown in FIGS. 4 to 7, there is an operating lever on a case 25 mounted on the rear wheel fender 4 on one side of the driver's seat 5, which can be operated longitudinally, horizontally, and diagonally. (Operation unit) 26, first and second potentiometers 27, 28, etc. that are interlocked with this operation lever 26 are incorporated. That is, the operating lever 26 is pivotally supported on a movable frame 29 via a horizontal shaft 30, and the movable frame 29 is supported on the case 25 side via a longitudinal shaft 31. With two axes, a shaft 30 and a front-rear shaft 31, as fulcrums, it can be operated in any direction as shown in FIG. Note that the operating lever 26 is elastically held at a neutral position by a spring (not shown). The first potentiometer 27 is the boom 10
It constitutes an elevation command means for instructing the elevation of the operating lever 26, and outputs a voltage command signal corresponding to the amount of operation of the operating lever 26, which is linked to the back and forth movement of the operating lever 26 via the horizontal shaft 30. The second potentiometer 28 constitutes a rotation command means for commanding the rotation of the bucket belt 13, and includes the front and rear shafts 31,
A voltage command signal is outputted via the movable frame 29 in conjunction with the left and right movement of the operating lever 26 and corresponding to the amount of operation of the operating lever 26 .

A push-button posture holding switch 32 is attached to the upper end of the operating lever 26. A hemispherical operating portion 33 is provided at the lower end of the operating lever 26,
Further, on the bottom side of the case 25, a rise switch 34, a fall switch 35, a dump switch 36, and a scoop switch 37 are provided front and back, left and right around the operating part 33. Each of these switches 34~
37 is adapted to be actuated by the actuating portion 33 when the operating lever 26 is operated by the maximum amount. Note that 38 is a flexible cover.

FIG. 8 shows a hydraulic circuit for the lift cylinder 11 and the bucket cylinder 14. Reference numeral 39 is a first electromagnetic valve for controlling the lift cylinder 11, which has an ascending solenoid 40 and a descending solenoid 41. A second electromagnetic valve 42 controls the bucket cylinder 14, and has a dump solenoid 43 and a scoop solenoid 44. Both of these solenoid valves 39 and 42 are proportional type.

FIG. 1 shows the electrical circuitry that drives and controls the solenoid valves 39,42. In FIG. 1, reference numeral 45 denotes a first discriminating means for discriminating the direction of movement during lifting and lowering, which consists of two comparators 46 and 47, a variable resistor 48 for setting a dead zone ±α between the comparators 46 and 47, and the like. When the command signal from the first potentiometer 27 is greater than the upper reference value (1/2V+α), the comparator 46 outputs a rising signal, and the lower reference value (1/2V−α)
When the value is smaller than , the comparator 47 outputs a falling signal. 49 is a second discrimination means for discriminating the operating direction during dumping/scooping, and like the first discrimination means 45, it is composed of two comparison parts 50, 51, a variable resistor 52, etc., and receives the command from the second potentiometer 28. In response to the signal, the comparator 50 outputs a dump signal,
The comparator 51 outputs scoop signals, respectively.

Reference numeral 53 denotes triangular wave oscillation means, which oscillates a triangular signal a of a constant frequency as shown in FIG.
54 is a first comparison means, which includes two comparison units 55 and 56.
As shown in FIG. 9, the command signal b from the first potentiometer 27 and the triangular wave oscillation means 53
A pulse signal c having a pulse width corresponding to a change in the command signal a is generated by comparing the triangular wave signal a from the command signal a. That is, the inputs of the command signal b and the triangular wave signal a are reversed in the comparators 55 and 56, and the comparator 55 turns on when the command signal b is larger than the triangular wave signal a, and turns off when the command signal b is smaller than the triangular wave signal a. 9th
Although the pulse signal c is generated according to the relationship shown in the figure, the comparator 56 turns on when the command signal b is smaller than the triangular wave signal a, and turns off when the command signal b is larger than the triangular wave signal a, which is the opposite of that shown in FIG. 57 is a second comparison means, which includes two comparison units 5;
8 and 59, and generates a pulse signal in the same way as the first comparing means 54 based on the command signal from the second potentiometer 28 and the triangular wave signal from the triangular wave oscillator 53.

Reference numeral 60 denotes a first driving means for driving the first solenoid valve 39, which includes switching elements 61, 62 connected to the respective solenoids 40, 41, and comparison parts 55, 5.
The analog switches 63 and 64 send pulse signals from the analog switches 63 and 64, and the signals from the comparators 55 and 56 of the first discrimination means 54 are sent to the analog switches 63 and 64.
When the pulse signal is input to the pulse signal 64, the switching elements 61 and 62 are turned on and off simultaneously with the pulse signal. 65 is a second driving means for driving the second electromagnetic valve 42, and like the first driving means 60, it is composed of switching elements 66, 67 and analog switches 68, 69.

Reference numeral 70 denotes setting means, which includes an ascending mode setting section 71 and a descending mode setting section 72. The ascent mode setting section 71 selects the posture holding voltage from the sample/hold section 73 and the aperture surface horizontal voltage Vr 2 necessary to level the aperture surface of the bucket 13 using a switch 74, and selects the attitude holding voltage from the sample/hold section 73 and the aperture surface horizontal voltage Vr ₂ necessary for leveling the aperture surface of the bucket 13, and selects the position when the boom 10 is ascending. Bucket 1 in
Mode 3 can be set to either attitude maintenance or horizontal aperture. When the holding switch 32 of the operating lever 26 is turned on, the sample/hold section 73 inputs the signal from the attitude sensor 16 at that time and holds it for a certain period of time (several seconds). The descending mode setting unit 72 sets the bottom surface voltage Vr ₁ necessary to make the bottom surface of the bucket 13 horizontal.
and the voltage indicating the inclination of the tractor body 1 from the inclination sensor 15 are selected by the switch 75, and the mode of the bucket 13 when the boom 10 is lowered is set to either the bottom horizontal or the bottom ground. ing. Incidentally, the inclination sensor 15 is for the bottom surface of the bucket 13. 76 and 77 are analog switches, and when a rising signal is received from the comparison section 46 of the first discrimination means 45, the analog switch 76 is turned on and selects the rising mode setting section 71 side, and when a falling signal is received from the comparison section 47. When this happens, the analog switch 77 is turned on to select the lowering mode setting section 72 side. Reference numeral 78 denotes an inverting section which inverts the signals selected by the analog switches 76 and 77 with reference to the reference voltage (1/2V) of the N terminal. 79 is a deviation detection means which adds the signal from the attitude sensor 16 and the signal from the reversing section 78 to detect the deviation between the two, and detects the deviation between the two.
It is designed to be inverted and amplified at 0. Reference numeral 81 denotes a manual/automatic changeover switch, which sends a command signal from the second potentiometer 28 in manual mode, and a signal from deviation detection means 79 in automatic mode to the second discriminating means 49 and second comparing means 57, respectively. It's getting old.

The switches 74, 75, 81 are mounted on the side of the case 25 of the operating device 24, as shown in FIG.
It is attached together with the power switch 78.

The determining means 45, the comparing means 54, and the driving means 50 constitute a boom control system, and the determining means 49, the comparing means 57, and the driving means 65 constitute a bucket control system.

In the configuration of the above embodiment, since the inclination sensor 15 is attached to the mast 8 side of the front loader 6,
The front loader 6 side is equipped with an attitude sensor 16 and an inclination sensor 15, which has the advantage of being able to be adjusted in advance at the factory during manufacturing, and also makes handling easier when attaching and detaching the front loader 6 to the tractor body 1. The sensor 15 may be attached to the tractor body 1 side.

Further, in the embodiment, the bucket 13 is used as an example of the working tool, but the tool is not limited to the bucket 13, and may be a fork or other attachment. In that case,
If you want to be able to attach and detach the work tool at will and replace it, a mounting bracket is pivotally attached to the tip of the boom 10, and the work tool is attached to this mounting bracket with a pin or the like in a removable manner. If the attitude sensor 16 is provided on the bracket side, even if there are various working tools, there is no need to provide the attitude sensor 16 for each working tool, which is very convenient.

(Effect of the invention) According to the invention, when the boom 10 is raised via the boom control system during automatic control, the raising mode setting section 7 is automatically activated by the raising signal at that time.
It is possible to select one of the working implement modes 1 and 13 to operate the working implement 13 in the working implement mode of the ascending mode setting section 71 that is suitable for raising the boom. Further, when the boom 10 is lowered, the lowering signal at that time automatically selects the working implement mode of the lowering mode setting section 72, and the working implement mode of the lowering mode setting section 72 is adapted to the lowering of the boom. The working tool 13 can be operated with the following steps. Therefore, at the same time as the boom goes up and down, the work implement can be controlled in the work implement mode that corresponds to the boom's up or down action without having to operate any switches, making operation much easier than before. , work can be done smoothly without fear of erroneous operation.

[Brief explanation of the drawing]

The drawings illustrate one embodiment of the present invention, in which Fig. 1 is an electrical circuit diagram of the control system, Fig. 2 is a side view of the tractor, Fig. 3 is a sectional view of the sensor, and Fig. 4 is an operation diagram. Rear view of the device, Figure 5 is a sectional rear view of the same, Figure 6 is a view taken along the X-X arrow in Figure 5, Figure 7 is a view taken along the Y-Y arrow in Figure 5, and Figure 8 is a hydraulic circuit. Figure 9 is a signal waveform diagram, Figure 10 is an explanatory diagram of the control position, and Figure 11 is a diagram of the control position.
The figure shows the relationship between Bucket's posture and the sensor.
Figure 12 is an explanatory diagram of voltage settings, Figure 13 and
FIG. 4 is an explanatory diagram of the operation, and FIG. 15 is a diagram showing the relationship between the attitude of the tractor and the sensor. 1...Tractor body, 6...Front loader,
10...Boom, 13...Bucket (work tool),
16... attitude sensor, 24... operating device, 26...
...Operation lever, 27, 28... Potentiometer (command means), 41, 42... Solenoid valve, 45, 49
... Discrimination means, 53 ... Triangular wave oscillation means, 54,
57... Comparison means, 60, 65... Drive means, 7
0...setting means, 71...rising mode setting section, 7
2... Descending mode setting section, 79... Deviation detection means.

Claims (1)

[Scope of claim for utility model registration] A boom 10 pivotably supported on the vehicle body 1 so as to be able to rise and fall freely,
A work tool 1 rotatably supported on this boom 10
3, in the boom work machine, the work implement control system is set with a work mode for controlling the attitude of the work implement 13 so that the work implement 13 maintains a required attitude when the boom is raised; The setting part 71 and the work tool 13 when the boom is lowered.
the work tool 13 so as to maintain the required posture.
A lowering mode setting section 72 is provided to set a work mode for controlling the posture of the boom, and the raising mode setting section 71 is selected when the boom is raised by a lift signal of the boom control system that controls the raising and lowering of the boom, and when the boom is lowered, the lowering mode setting part 71 is selected. A control device for a boom-type work machine characterized in that mode switching means 76 and 77 for selecting a lowering mode setting section 72 are provided.