JPH0474965B2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a tractor and a sowing machine in which a working machine attached to a towing vehicle is brought into contact with the ground during work and raised when turning the machine, etc. The present invention relates to an automatic upper limit control device for raising the working machine of agricultural tractors, such as a seedling machine, a seedling planting machine, or a fertilizer applicator.

(b) Prior art Conventionally, a work machine is attached to a towing vehicle so that it can be raised and lowered, and the work machine is raised when the machine turns or goes over a ridge, and the upper limit position of the work machine is limited by a stopper, and lifts. A working machine lift upper limit control device for an agricultural tractor is already known, which is set by adjusting a sensor.

(c) Problems to be Solved by the Invention In the above-mentioned known lifting upper limit device for agricultural tractors, in which the upper limit control position for lifting is limited by a stopper, the actuating member of the lift mechanism is activated each time the working implement is raised. There is a drawback that the oil pressure continues to rise to the relief pressure when the stopper comes into contact with the stopper, and the stopper and the members that collide with it are damaged.Also, the method of adjusting the upper limit value of the lift sensor is extremely troublesome to operate, and is difficult to use. If the upper limit value is incorrect during construction, it becomes impossible to raise the work equipment to the upper limit, and there is a problem that the work equipment may destroy the ridge when going around the headland during final leveling work such as plowing work. Ta.

(d) Means for Solving Problems The present invention includes a lift sensor 15 attached to a lift mechanism for raising and lowering a working machine, and detects a lift limit detection value detected by the lift sensor 15 at the upper limit of the lift mechanism after the engine is started. By configuring the microcomputer 20 to store a detected value close to the upper limit detection value and use this stored value as the upper limit for subsequent lifting of the work equipment, it is possible to continue the state in which the hydraulic pressure has increased to the relief pressure when the work equipment is raised. This prevents damage to the stopper and the operating members of the lift mechanism, and even if there is a manufacturing error in the lift mechanism or the detection value of the lift sensor changes, it can be used after starting the engine to start work. There is no need to adjust the lift sensor during assembly, and once the detected value is stored, the work equipment can be reliably raised to a predetermined height during a series of subsequent operations. In this way, the above-mentioned problems were solved.

(E) Function In the assembly process, the lift sensor is assembled as specified, the engine is started to start work, and when the lift mechanism lifts the work equipment, the lift sensor detects this and the microcomputer transmits the detected value. The value is stored as it is or as a slightly smaller value, and the lift mechanism is automatically controlled using this stored value as the upper limit value for lifting the work implement thereafter.

(f) Embodiment An embodiment of the present invention will be explained about a tractor shown in the drawings. 1 has an engine 2 mounted on the front part,
This tractor is equipped with a lift lever 6 equipped with a setting device 5 consisting of a potentiometer on the side of the driver's seat 3, and a rotary device 7 as a working device is installed at the rear with an upper link 8 and lower links 9, 9. The lift arm 10 of the lift mechanism is connected to the lower links 9, 9 by a lift rod 11, and the lift arm 10 and the passive arm 12
The lift shaft 13 rotates integrally with the lift arm 1.
A lift sensor 15 is attached to detect the angle of 1.

The lift shaft 13 is supported near the rear of the hydraulic case 16, and the passive arm 12 is connected to a piston rod 18a of a hydraulic cylinder 18, which expands and contracts by turning on and off an ascending solenoid 17 and a descending solenoid 18 of electromagnetic valves. ing.

Further, the set value of the setting device 5 and the detected value of the lift sensor 15 are inputted to a microcomputer 20 as shown in FIG. Input ON and OFF signals.

In the above-described tractor, the lift sensor 15 is assembled at a predetermined angle even if there are manufacturing errors in the lift mechanism and its related parts in the assembly process.
When the engine 2 is started at the beginning of work, and the lift lever 6 is then tilted fully upwards, the set value is greater than the detected value of the lift sensor 15, so the lift solenoid 17 of the electromagnetic valve is turned ON and the rotary device is activated. 7 rises, during which time the passive arm 12 of the lift mechanism is pushed by the piston rod 18a of the hydraulic cylinder 18 and rotates rearward.
Finally, it collides with the inner wall surface of the hydraulic case 16, which acts as a stopper, and stops, and the hydraulic oil returns from the relief valve to the transmission case that constitutes the tank. At that time, the detection value L of the lift limit position detected by the lift sensor 15 ₁ is stored in the microcomputer 20.

Next, the position lever 6 is tilted downward to lower the work machine to perform the work. Next, when the position lever 6 is tilted up to the upper end in order to rotate the machine, the detected value of the lift sensor 15 becomes the above-mentioned L ₁ When the lift reaches the upper limit, the lift solenoid 17 is turned off, and the work equipment can be reliably stopped at the lift limit.

In addition, after interrupting work and taking a break, or when the engine 2 is started and the work equipment is raised to the upper limit for the first time in order to start work in the next season, the detection value detected by the lift sensor 15 is sent to the microcomputer. stores L ₂ as the rising limit detection value as described above,
When the work machine subsequently ascends, it is automatically controlled using the detected value _L2 as the upper limit of the elevation.

7-8 show other embodiments,
When the microcomputer 20 stores the upper limit detection value L ₁ or L _{2 .} . . of the lift sensor 15 in the above-described embodiment, it subtracts or adds α to the detection value L ₁ . α is lift arm 10
If the height of the rotary device 7 changes by 8 to 10 mm when the angle changes by 1 degree, subtract the slight amount of descent of the lift arm angle by 2 to 3 degrees, preferably 1 to 2 degrees, that is, aim for 1.5 degrees. As a result, when the working machine subsequently ascends, α is subtracted from each of the upper limits of elevation L ₁ , L _{2 .} . . and automatically controlled.

In this case, the passive arm 12 is connected to the hydraulic case 16.
Since the lift stops before colliding with the inner wall surface of the lift mechanism, it is possible to reliably prevent the relief valve from continuing to operate and damage to the operating member of the lift mechanism.

The above-mentioned increase limit value may be either the maximum value or the minimum value of the input data, and the calculation of α may be either subtraction or addition, and the data is processed as appropriate.

(G) Effects of the Invention As described above, the present invention includes a lift sensor 15 attached to a lift mechanism for raising and lowering a working machine, and detects the upper limit of the lift detected by the lift sensor 15 at the upper limit of the lift of the lift mechanism after the engine is started. A detection value close to the limit detection value is stored in the microcomputer 20, and this stored value is set as the upper limit for subsequent lifting of the work equipment, so when the engine 2 is started and the work equipment is raised to the upper limit, the lift sensor The rising limit detection value detected by 15 is stored in the microcomputer,
Based on this, the upper limit of the lift of the work equipment will be automatically controlled from then on, and if there is a manufacturing error in the assembly process or the set value of the lift sensor fluctuates, the set value will not need to be corrected. This is advantageous when moving around the headland because the work equipment can be raised to a position equivalent to the lifting limit. Also, setting up the lift sensor is simple and easy.

[Brief explanation of the drawing]

The drawings show one embodiment of the invention,
Fig. 1 is a cross-sectional view showing the lift device in the ascending position, Fig. 2 is a cross-sectional view showing the same as above in the descending position, Fig. 3 is a side view of the tractor equipped with the work equipment, Fig. 4 is the control circuit diagram, and Fig. 5 is the control circuit diagram. 6 is an operation timing diagram, FIG. 6 is a flowchart, FIG. 7 is an operation timing diagram in another embodiment, and FIG. 8 is a flowchart. 2... Engine, 5... Setting device, 6... Position lever, 7... Rotary device, 10... Lift arm, 15... Lift sensor, 18... Hydraulic cylinder, 20... Microcomputer.

Claims (1)

[Claims] 1. A lift sensor 15 is attached to the lift mechanism that raises and lowers the working machine, and after the engine starts, the lift limit detection value detected by the lift sensor 15 at the upper limit of lift mechanism or a detection value close to the rise limit detection value is stored in the microcomputer 20. An automatic upper limit adjustment device for lifting a working machine for an agricultural tractor, characterized in that the stored value is set as the upper limit for lifting the working machine thereafter.