JPH0789766B2 - Hydraulic control device for tractor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device for a tractor, and more particularly to a hydraulic control device capable of improving the operability when the working machine is attached and detached, and accurately and safely lifting and lowering the working machine.

[0002]

2. Description of the Related Art When connecting a working machine such as a rotary cultivator arranged at the rear of a tractor, the height of the connecting portion is adjusted while operating a hydraulic operating lever while riding on the tractor. Therefore, some levers and switches for raising and lowering the working machine are provided at the rear of the machine body.

[0003]

Among such conventional devices, the former type, that is, a hydraulic operation lever is provided at the rear of the machine body, and the hydraulic operation lever and the hydraulic lever provided at the side portion of the seat are provided. In the case of interlocking and connecting via a mechanical interlocking means such as a rod or a wire, these interlocking members must be arranged in a narrow space between the mission case and the fender, and the work is In addition, there is a problem that when the linking means operates, it hits the lift arm or other equipment and the operation is not reliable.

Further, in the latter type, that is, in the case where an elevating switch is provided at the rear of the machine body, the lift arm rotates up and down when the elevating switch is operated, but before operating the elevating switch, the hydraulic operation lever is operated. Control mode that prohibits operation on the − side or gives priority to operation on the up / down switch side.
Since it is necessary to provide a cord, the circuit structure becomes complicated, and if the mode switching is forgotten, there is a problem that the working machine connecting portion at the rear of the machine body cannot be adjusted up and down.

[0005]

The present invention has been proposed in view of the above-mentioned problems, and the following technical means have been taken. That is, the lift arm 6 is provided with a position setter 17 for setting the rotation angle of the lift arm 6 and a lift arm angle sensor 18 for detecting the position of the lift arm 6, 6, and the set value by the position setter 17 and the lift arm are provided. -Med angle sensor 1
8 to obtain a deviation from the detected value, and the proportional proportional solenoid valve 1 for rising is commanded by the control unit to eliminate this deviation.
9 and a proportional control solenoid valve 20 for lowering the work machine 9, a tractor having a position control mechanism for raising and lowering the work machine 9 is provided with an elevating switch 21 for elevating the work machine separately from the position setter 17. 21
Is connected to the input side of the control section, and when the control section is operated, the lift arms 6 and 6 are configured to move up and down at a predetermined speed irrespective of deviation by a command from the control section. After the lift arms 6 and 6 are rotated up and down, a hydraulic control device for a tractor is provided, which is provided with a restraining means for prohibiting the position control.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. First, the structure will be described. 1 is a tractor.
The engine 2, the clutch housing 3, and the transmission case 4 are fixed in series from the front side in this order to form a machine body. A hydraulic cylinder case 5 is mounted on the upper portion of the transmission case 4, and lift arms 6, 6 are rotatably and pivotally mounted on the left and right sides of the rear portion thereof.

A three-point link mechanism composed of lower links 7, 7 and a top link 8 is provided at the rear of the machine body, and a rotary tiller 9 is vertically movably connected by this link mechanism. 10 and 10 are lift rods,
The lift arms 6 and 6 are connected to the lower links 7 and 7.

The rotary tiller 9 includes a tiller 11 including a tiller shaft and a tiller, a main cover (not shown) covering the upper part of the tiller 11, and a rear cover 12 pivotally attached to the rear of the main cover. The input shaft 14 is composed of a gear case and the like, and the input shaft 14 and the PTO shaft 13 of the tractor are interlockingly connected by a universal universal joint 15 so that the rotational power on the tractor-1 side can be transmitted. It is configured to be transmitted to the rotary cultivator 9 side.

A position lever as a position setting device for operating the hydraulic lifting device is provided on the lateral side of the cockpit 16.
When the position lever 17 is rotated in the front-back direction, the lift arms 6 and 6 are rotated according to the rotation position of the position lever 17. A lift arm angle sensor 18 composed of a potentiometer for detecting the rotation angle of the lift arm 6 is provided on one side of the lift arms 6 and 6 to support the position lever 17. When operated, a position control mechanism is constructed in which the lift arms 6, 6 rotate according to their positions.

The control valve for controlling the hydraulic lifting control device is composed of a proportional solenoid valve, and includes an ascending proportional solenoid valve 19 and a descending proportional solenoid valve 20.
Alternatively, the spool of the control valve is switched by passing an electric current, and the control flow rate is changed in proportion to the amount of electric current. At the lower rear end of the mission case 4, an elevating switch 21 for fine adjustment for always operating the hydraulic elevating device at a predetermined low speed is provided. Two
Reference numeral 2 is an A / D converter, and 23 is a CPU that performs arithmetic processing.

When the position lever 17 is operated, its output voltage is input to the CPU 23 through the A / D converter 22, and when the lift arms 6 and 6 rotate, the lift arm 6 is rotated.
The detected value of the angle sensor 18 is C through the A / D converter 22.
The current is input to the PU 23, and a current corresponding to the deviation is supplied to the rising proportional solenoid valve 19 or the falling proportional solenoid valve 20 until the set value and the detected value match. As shown in FIG. 2, the fine adjustment lift switch 21 is
It is directly input to the CPU 23 without passing through the D converter 22, and as long as the elevating switch 21 is continuously pressed, either solenoid valve 19 or 20 is excited with a predetermined current. In this case, a minute control current is passed through the solenoid valves 19 and 20 regardless of the deviation, the movement of the spool is suppressed, and the lift amount of the lift arms 6 and 6 is suppressed.
In this case, press the lift switch 21 to lift the lift arm 6,
Even when 6 is rotated, the lift arm angle sensor 18 is always
Its position is monitored by. When the lift arms 6 and 6 are rotated by pushing the lift switch 21 and the set value of the position lever 17 and the detection value of the lift arm angle sensor 18 do not match, the check control for prohibiting the position control is performed. The means is configured to operate. The release of the restraint means is achieved by operating the position lever 17 so that the position set value and the position detected value match. Next, the operation will be described based on the flow chart shown in FIG.

When the position lever 17 is operated and the fine adjustment elevating switch 21 is not pressed, first, the setting by the position lever 17 and the rotational position of the lift arms 6, 6 are coincident with each other. It is compared (steps S1 and S2). When they match, the operations of the lift arms 6 and 6 are permitted and the control routine for position control is executed (steps S3 and S2).
4). At this time, the proportional solenoid valve 1 for increasing the current corresponding to the deviation depending on the operating direction of the position lever 17
9 (steps S5, S6, S7) to raise the working machine, or the lowering proportional solenoid valve 20 is excited (steps S5, S6, S8) to lower the working machine, or maintain the neutral state. (Steps S5, S
6, S9). Here, when the set position of the position lever 17 and the positions of the lift arms 6, 6 do not match, the operation of the hydraulic lifting device by the position lever 17 is prohibited (steps S2, S4, S5, S9), The control valve maintains the neutral state.

On the other hand, when the operator leaves the seat and goes around to the rear part of the machine body to detach the work machine, the lift arms 6, 6 need to be finely adjusted in the vertical direction. In this case, For this purpose, the fine adjustment lift switch 21 is pressed.
Then, the restraint means is activated to prohibit the operation of the lift arms 6 and 6 by the operation of the position lever 17, and the spool of the control valve is set to a minute opening amount (steps S10, S11, S12), Depending on the operating direction of the elevating switch 21, the ascending or descending solenoid valves 19 and 20 are excited to rotate the lift arms 6 and 6 at a predetermined low speed.

After this operation, the set value of the position lever 17 provided on the side of the seat differs from the actual detected value of the lift arm angle sensor 18. In this case, first, As described above, if the position lever 17 is rotated in the front-rear direction so that the position set value and the position detection value match, the position control by the position lever 17 becomes possible.

Although the position lever 17 is used as the position setting device in this embodiment, a dial type adjusting knob may be used.

[0016]

Since the present invention is constructed as described above, it has the following technical effects. That is, when connecting a working machine such as the rotary tiller 9 at the rear of the machine body, the lift arms 6, 6 can be moved up and down by using the lifting switch 21, so that the tractor and the working machine can be operated. It is easy to connect and disconnect the work machine, and the work machine can be quickly attached and detached.
In this case, when the lift switch 21 is operated to rotate the lift arms 6 and 6 up and down, a predetermined current is applied to the proportional solenoid valves 19 and 20 to slow the operation speed, so that the connecting work is performed. It will be easier and easier for even inexperienced people to handle. Further, according to the present invention, when the working machine is connected, a special operation for prohibiting the position control on the seat side is not required, and the lift switch 21 is provided.
Position control is automatically prohibited simply by operating
Since the lift arms 6 and 6 can be rotated up and down in that state, the working efficiency can be greatly improved.

[Brief description of drawings]

FIG. 1 is a side view of a tractor and a working machine.

FIG. 2 is a block diagram.

FIG. 3 is a flowchart.

[Explanation of symbols]

 1 tractor 2 engine 3 clutch housing 6 and 6 lift arm 17 position setting device (position lever) 18 lift arm angle sensor 21 lift switch

Claims (1)

[Claims] 1. A position setting device 17 for setting the rotation angle of the lift arms 6, 6 and a lift arm angle sensor 18 for detecting the positions of the lift arms 6, 6 are set by the position setting device 17. A deviation between the value and the value detected by the lift arm angle sensor 18 is calculated, and in order to eliminate this deviation.
According to the command from the control unit,
Tractors with position control mechanism for lifting the lowering proportional solenoid valve 20 working machine 9 is controlled to a - in, only setting the lifting switch 21 for separately working machine lifting from said position setter 17, the lift switch 21 In front
Connected to the input side of the control unit and controlled when operated.
Lift arm at a predetermined speed regardless of deviation according to the command from the
6, 6 is configured to rotate up and down, and the up / down switch 21
2. A hydraulic control device for a tractor, characterized in that, after the lift arm 6 is lifted and lowered by the above-mentioned operation, a restraint means for prohibiting the position control is provided.