JPH0611203B2 - Hydraulic control device for tractor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device for a tractor, and more specifically, it improves operability when a work machine is attached / detached, and
The present invention relates to a hydraulic control device capable of accurately and safely controlling the lifting and lowering of a work implement.

[Prior Art] When connecting a working machine such as a rotary tiller mounted at the rear of a tractor, it is difficult to adjust the height of the connecting section while operating the hydraulic operating lever while riding on the tractor. , Some have a lever and switches for raising and lowering the working machine at the rear of the machine body.

[Problems to be Solved by the Invention] In such a conventional device, the former type, that is,
A hydraulic operation lever is provided on the rear part of the machine body, and the hydraulic operation lever and the hydraulic lever provided on the lateral side of the seat are interlockingly connected through a mechanical interlocking means such as a rod or a wire. It must be installed in a narrow space between the fender and
When the linking means operates, it hits the lift arm and other devices, and there is a problem that the operation is not reliable.

Also, 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 in the vertical direction when the elevating switch is operated.
The setting position on the side of the seat on the hydraulic lever side and the position of the lift arm will be different, so if the operator does not incorporate any restraint mechanism or priority circuit, the lift arm will be expected at the moment when the operator moves the hydraulic lever. There is a problem that it starts to move in a direction that is not right.

[Means for Solving the Problem] The present invention has been proposed in view of the above-mentioned problems, and has taken the following technical means.

That is, a position setter 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 provided, and the set value by the position setter 17 and the lift arm angle sensor are provided. In a tractor having a position control mechanism for raising and lowering the working machine 9 by exciting the ascending proportional solenoid 19 and the descending proportional solenoid 20 so that the detected values by 18 coincide with each other, in addition to the position setter 17, a lift is provided. Arms 6, 6
Lifting switch 2 for raising and lowering the robot at a constant minute speed
1 is provided at the rear of the machine body, and after the lift arms 6 and 6 are rotated by the lifting / lowering switch 21, a restraint means for prohibiting the operation of the position control mechanism is provided. And the detected value are substantially coincident with each other by operating the position setter 17 so that the hydraulic control device in the tractor is configured.

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

In addition, lower links 7, 7 and top link 8 are located at the rear of the fuselage.
Is provided, and the rotary tiller 9 is connected by the link mechanism so as to be vertically movable.

10 and 10 are lift rods, which are lift arms 6,
6 and the lower links 7 and 7 are connected.

The rotary tiller 9 includes a tiller 11 including a tiller shaft and a tiller, a main cover (not shown) that covers the upper portion of the tiller 11, and a rear cover 1 pivotally attached to the rear of the main cover.
2. It consists of a gear case etc. around the input shaft 14,
The input shaft 14 and the PTO shaft 13 of the tractor are connected by a universal joint 15 which is expandable and contractible, and the tractor 1
The rotary power of the side is transmitted to the rotary tiller 9 side.

A position lever 17 as a position setter 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-rear direction, the position lever 17 is moved in accordance with the rotation position of the position lever 17. Lift arms 6, 6 rotate. 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 pivot arms of the lift arms 6, 6, and when the position lever 17 is operated, its position A position control mechanism for rotating the lift arms 6, 6 is constructed in accordance with the above.

The control valve for controlling the hydraulic lifting control device is composed of a proportional solenoid valve, and the spool of the control valve is switched by selectively passing a current to the proportional solenoid 19 for rising and the proportional solenoid 20 for falling, and the current amount is changed. The control flow rate is proportionally changed.

The lower part of the rear end of the mission case 4 is provided with a fine-adjustment lift switch 21 for slightly operating the hydraulic lift device at a constant speed.
Is provided. Reference numeral 22 is an A / D converter, and 23 is a CPU that performs arithmetic processing.

When the position lever 17 is operated, the output voltage is A
It is input to the CPU 23 via the / D converter 22, and when the lift arms 6 and 6 rotate, the lift arm angle sensor 1
The detected value of 8 is input to the CPU 23 via the A / D converter 22, and the proportional solenoid 19 for rising or the proportional solenoid 20 for falling is excited until the set value and the detected value match.

As shown in FIG. 2, the fine adjustment lift switch 21 is directly input to the CPU 23 without passing through the A / D converter 22, and as long as the lift switch 21 is continuously pressed,
One of the solenoids 19 and 20 is excited. In this case, a minute and constant control current is applied to the solenoids 19 and 20, and the movement of the spool is suppressed so that the lift arm 6,
The lifting amount of 6 is suppressed. In this case, the lifting switch 21
Even when the push arms are pushed to rotate the lift arms 6, their positions are always monitored by the lift arm angle sensor 18. When the lift arms 6 and 6 are rotated by pressing the up / down switch 21 and the set value of the position lever 17 and the detected value of the lift arm angle sensor 18 do not match, the restraint means for inhibiting the position control is activated. It is configured to do. The release of the restraint means is achieved by operating the position lever 17 so that the set position value and the detected position 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 lift switch 21 is not pressed, first,
Setting with position lever 17 and lift arms 6, 6
It is compared whether the rotational positions of the two are the same (step), and when they are the same, the lift arm 6,
The operation of 6 is permitted, and the control routine for position control is executed (step). At this time, depending on the operating direction of the position lever 17, the lifting proportional solenoid 19
Are excited (step) to raise the working machine, or the proportional lowering solenoid 20 is excited (step) to lower the working machine or maintain the neutral state (step).

Here, when the set position of the position lever 17 and the positions of the lift arms 6 and 6 do not match, the operation of the hydraulic lifting device by the position lever 17 is prohibited (step), and the control valve maintains the neutral state.

On the other hand, when the operator moves away from the seat and turns around to the rear part of the machine body to detach the work machine, it is necessary to slightly adjust the vertical movement of the lift arms 6 and 6 in this case. Push the lift switch 21. Then, the operation of the lift arms 6 and 6 by the operation of the position lever 17 is prohibited, the spool of the control valve is set to a minute fixed opening amount (step), and the solenoid 19 for raising or lowering depending on the operating direction of the raising / lowering switch 21. , 20 are excited to slightly rotate the lift arms 6, 6 at a constant speed.

After this operation, the set value of the position lever 17 provided on the lateral side of the seat and the actual detected value of the lift arm angle sensor 18 will be different, but in this case, as described above, If the position setting value and the position detection value are matched by rotating the lever 17 in the front-rear direction, the position control by the position lever 17 becomes possible.

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

[Effects of the Invention] Since the present invention is configured as described above, it has the following technical effects.

That is, in a normal operation, the lift arms 6 and 6 are rotated in a direction to eliminate the deviation while comparing the position set value and the lift arm angle sensor value, and when the deviation is large, Since the lift arms are rotated at high speed and, on the contrary, when the deviation is small, the lift arms 6 and 6 are rotated at a minute speed, the work machine can be quickly moved to the target position. Since the shock at the time of stop is small, the working machine can be smoothly moved up and down.

Further, when connecting a working machine such as a rotary tiller 9 at the rear of the machine body, a lifting / lowering switch 21 provided at the rear of the machine body is used to finely move up and down while confirming the movements of the lift arms 6, 6 directly. Therefore, the work of connecting the tractor and the work machine is facilitated, and the operating speed of the lift arms 6 and 6 is constant over the entire operating range while the elevating switch 21 is being operated. Therefore, the lift arms 6, 6 can be accurately positioned, and the work machine can be quickly attached and detached.

Further, while the elevating switch 21 is being operated, the position control by the position setter 17 is in a state of being prohibited.
Since it is necessary to consciously move 7 to try to match the position setting value with the position detection value, it is safe. As soon as the hydraulic lever is moved, the lift arms 6 and 6 rotate in an unexpected direction. It is possible to avoid the risk of doing it.

[Brief description of drawings]

1 is a side view of a tractor and a working machine, FIG. 2 is a block diagram, and FIG. 3 is a flow chart. Explanation of code 1 …… tractor 2 …… engine 3 …… clutch housing 6,6 …… lift arm 17 …… position setter (position lever) 18 …… lift arm angle sensor 21 …… elevation switch

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-54-153129 (JP, A) Actually opened 59-175312 (JP, U) Actually opened 57-183822 (JP, U) JP-B 59- 39083 (JP, B2)

Claims (1)

[Claims] 1. A position setter 17 for setting the rotation angle of the lift arms 6, 6 and a lift arm angle sensor 18 for detecting the position of the lift arms 6, 6, and a set value by the position setter 17 and a lift. Ascending proportional solenoid 1 so that the value detected by the arm angle sensor 18 matches
In a tractor having a position control mechanism for exciting the working machine 9 by exciting the lowering proportional solenoid 9 and the lowering proportional solenoid 20, for lifting and lowering the lift arms 6, 6 at a constant minute speed separately from the position setting device 17. An elevating switch 21 is provided at the rear part of the machine body, and after the lift arms 6 and 6 are rotated by the elevating switch 21, a restraint means for prohibiting the operation of the position control mechanism is provided, and the restraint means is released. A hydraulic control device for a tractor, characterized in that it is constructed by operating the position setter 17 at a position where the position set value and the detected value substantially match.