JP2508663B2 - Down valve cutting device for ground work machine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a down valve cut device for a ground work machine that is run by being pulled by a tractor, and more particularly to a plurality of devices including a depth work mode. For a tractor with a work mode of, a valve cutting device that can switch to a state in which the amount of oil flowing from the lift cylinder to the tank is increased by the internal pressure in the lift cylinder when the depth work mode is selected. is there.

[Conventional technology]

Conventionally, in a tractor having a plurality of working modes including the depth working mode of this type of ground working machine, for example, when the depth working mode is selected by a working mode switching switch, the rotary working is performed by the working depth control. .
Thus, this tilling depth control device outputs an operation command from the control unit so as to perform a raising / lowering operation according to the difference between the value detected by the tilling depth sensor and the tilling depth setting device, and the proportional solenoid valve for raising is output. Alternatively, the lift arm is moved up and down via a descending proportional solenoid valve to perform rotary work by controlling the working depth.

Thus, a tractor having a plurality of working modes is provided with a lowering valve in parallel with the lowering proportional solenoid valve.
When the lowering proportional solenoid valve cannot output the oil flow rate proportional to the electric signal due to the pressure drop in the lift cylinder at the time of the lowering command output, the lowering speed of the lift arm decreases. Therefore, in order to make up for this inconvenience, the lowering valve is provided, and when the lowering proportional solenoid valve outputs a lowering command and the lift cylinder internal pressure is lowering, the lowering of the lift arm is lowered by opening it. I try to increase the speed.

[Problems to be solved by the invention]

In a conventional tractor having a plurality of working modes in which the lowering valve is used in combination, for example, when the ground working machine is moved up and down by a position lever or a lifting switch, and when the ground working machine is lifted, Since the lift arm is rotated in the raising direction only by hydraulic pressure regardless of the weight, the lift arm can always be raised at a constant speed. However, when lowering the lift arm, the ground working machine is extremely lightweight, or when the ground working machine is mounted, the pressing force acting on the oil passage that releases the pressure oil in the lift cylinder to the tank is reduced. are doing. Therefore, the lowering valve provided in parallel with the lowering proportional solenoid valve is automatically opened when a lowering command is output to the lowering proportional solenoid valve and a decrease in the pressing force in the lift cylinder is sensed. Let the pressure oil escape into the tank. As a result, the lift arm can be rapidly lowered. This means that when the working mode is switched to the depth working mode and the rotary plowing depth control is performed by automatic control, for example, the rotary claw abuts on a stone block or a hard soil block, and this rotary impact causes the rotary to float. As a result, the weight of the rotary working machine is reduced and the pressing force in the lift cylinder is reduced. Then, in this state, if a descending command is accidentally output to the descending solenoid valve by automatic control, the descending valve is opened, and the rotary working machine is rapidly lowered. In such a case, when the rotary work is carried out smoothly and stably by controlling the plowing depth, there is an inconvenience that deep plowing places are generated in some places due to the operation of the descending valve.
Therefore, in a tractor having a descending valve and having a plurality of working modes including a depth working mode, there arises a problem for solving the above-mentioned inconvenience.

[Means for solving problems]

In view of the above problems, the present invention has been proposed as a solution, and is provided with a tilling depth sensor for detecting the working depth of a ground working machine that is vertically movable by a hydraulic lifting mechanism. The lift cylinder has a plurality of working modes including a depth working mode in which lifting and lowering operations are performed according to the difference between the value detected by the depth sensor and the value set by the tilling depth setting device. In a tractor equipped with a valve capable of switching to a state in which the amount of oil flowing from the lift cylinder to the tank is increased by the internal pressure of the valve, when the depth working mode is selected, the valve moves from the lift cylinder to the tank. It is intended to provide a descent valve cut device for a ground work machine, characterized in that a control unit for preventing switching to a state in which the amount of flowing oil is increased is provided in the CPU.

[Action]

The present invention can be controlled by position control alone, or position control and depth control that are mix controls,
Or, regardless of whether it is a mixed control of position control and draft control, etc., in a tractor having a plurality of working modes including a depth working mode, when the depth working mode is selected, the CPU from the CPU According to the command, the valve that can switch to a state in which the amount of oil flowing from the lift cylinder to the tank is increased by the internal pressure in the lift cylinder will not operate, so that the rotary work by the working depth control will always maintain a constant working depth. Therefore, smooth work is promoted.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the attached drawings. For convenience of description, a configuration that is conventionally known will be described at the same time. As shown in FIG. 2, a ground work implement (2) such as a rotary is attached to the rear part of the tractor (1) as a towing vehicle to a pair of left and right lift arms (3) and (3), and left and right lift rods (4) ( 4) via left and right lower links (5) and (5) swinging up and down via a work implement connecting link (7) consisting of a central upper top link (6), and this work implement connecting The link (7) is configured to move up and down by a hydraulic lifting mechanism (9) that lifts and lifts the lift arms (3) (3) by a lift cylinder (8) using hydraulic pressure. . In addition, as shown in FIG. 1, the control of supply / discharge of pressure oil to / from the lift cylinder (8) is performed by manually operating an elevating switch (S3) provided near the driver's seat as shown in FIG. An operation command of the CPU (10) configured by a microcomputer or the like is amplified by the ascending drive unit (11) or the descending drive unit (12) and then the ascending proportional solenoid valve (13) or The proportional solenoid valve for lowering (14) is opened and closed, whereby the pressure oil of the pump (15) is supplied to the lift cylinder (8), and the lift arms (3) (3) rise or lift. The pressure oil of the cylinder (8) is discharged and the lift arms (3) and (3) descend. The ground work machine (2) can be moved up and down based on the ascent and descent of the lift arms (3) (3). Secondly, a lift arm angle sensor (S1) formed by connecting a position lever (I1) provided near the cockpit and a detection axis of a rotary potentiometer to the lift arm (3).
Are connected to the CPU (10) respectively, and the position lever (I
In order that the height detection value detected by the lift arm angle sensor (S1) matches the set value set by the operation of 1), the elevating command is issued from the CPU (10) to the ascending drive unit (11). ), Or output to the descending drive unit (12) to perform up-and-down control (position control).

Thirdly, for automatic control of the working depth, the working depth setting value (I2) consisting of a volume such as a volume is used to set the working depth setting value set by the operator to the working depth sensor (2) of the ground work machine (2). S
The solenoid valve (13) for raising and the solenoid valve (14) for lowering the pressure oil flow opening area in proportion to the amount of current applied to the solenoid section until the depth value detected in 2) matches. A proportional solenoid valve that controls opening and closing is used. A control current of a magnitude proportional to the difference between the plowing depth set value and the plowing depth detection value is output from the CPU (10), and a pulse with a pulse width proportional to this control current value is output. An electric current is applied to the solenoid valve, and the ground working machine (2) is moved up and down to control the working depth.

Further, the working depth sensor (S2) in the illustrated example uses a device which detects the movement of the rear cover (17) which is in sliding contact with the surface of the cultivated soil by, for example, a linear movement type potentiometer (18), The rear cover (17), which is screwed to the rear part of the body of the ground working machine (2) so as to be able to rotate up and down, is fixed by the lifting rod (19) when in a lifting position where no plowing work is performed. Although it is held at the height, it rotates upward when it touches the ground as the ground work implement (2) descends from the lifting posture, and the working depth corresponding to this rotation position is displayed on the potentiometer (18). Is detected.

Therefore, the ground work implement (2) is the position lever (I1).
Alternatively, an operator manually operates the lifting switch (S3) to raise and lower the ground work implement (2), and control the working depth, draft control (not shown), etc. It goes up and down automatically.

Further, in the embodiment diagram of FIG.
Although the mix control unit for the position control and the plowing depth control is shown, it is not limited to the control unit.

The mix control of this embodiment is operated via the work mode switching board (T). That is, the work mode switching board (T) can be switched to the position control, the plowing depth control, and the draft control (not shown), respectively.

In addition, as shown in FIG. 1, a proportional solenoid valve for lowering (1) for releasing the pressure oil in the lift cylinder into the tank.
4) and a down valve (W) are provided in parallel, and this down valve (W) reduces the pressure of the pressure oil in the lift cylinder (8) according to a command from the CPU (10), and further, When the lowering proportional solenoid valve (14) receives a lowering command, the lowering proportional solenoid valve (14) is opened to release the pressure oil in the lift cylinder (8) into the tank. That is, for example, when the ground work implement (2) is attached to the tractor (1), the position lever (I1) or the elevating switch (S3) is operated to lower the lift arm (3) to a predetermined position. When it is necessary or when the weight of the ground work implement (2) is extremely light, the pressure of the pressure oil in the lift cylinder (8) decreases, and accordingly, the descending speed of the lift arm also becomes extremely large. It becomes a low speed and hinders the smoothness of work. Therefore,
At this time, the lift cylinder (8) is provided with a sensor (not shown), and the weight of the ground working machine (2) for lowering the lift arm (3) at a predetermined speed is insufficient. In the case where the ground work machine (2) is not attached as described above, that is, when the internal pressure in the lift cylinder (8) becomes a certain value or less, the lift cylinder (8) is provided in the lift cylinder (8). The information from the sensor
0), the CPU (10) processes the information, and opens the lowering valve (W) provided in parallel with the lowering proportional solenoid valve to open the pressure oil in the lift cylinder (8). Was released into the tank, and the lift arm (3) or the ground work implement (2) was immediately lowered accordingly.

As described above, in the tractor equipped with the down valve (W), when the working mode is switched to the depth working mode, the CPU (1
The operation of the down valve (W) is prohibited by an operation command from the down valve cut control unit (10a) provided in (0). If the rotary operation is performed by controlling the working depth of the descent valve (W) and controlling the plowing depth, as described above, the plowing claw of the rotary impacts a stone block or a hard soil block,
The reaction force lifts the rotary. In that case, the internal pressure of the lift cylinder (8) becomes close to zero, and when the lowering proportional solenoid valve (14) receives a lowering command from the CPU (10) at this time, the lowering valve (W) also has a lowering valve (W). The operation command for opening W) is output and the down valve (W) is opened, the pressure oil in the lift cylinder (8) is released into the tank, the rotary rapidly descends, and the overrun occurs above the target position. To do.
Therefore, stable rotary work by controlling the working depth is hindered. In order to eliminate such inconvenience, it is inevitable that the operation of the down valve (W) can be prohibited during the rotary work by the plowing depth control. Therefore,
When the depth work mode is selected by the work mode switching panel (T), an operation command is output from the down valve cut control unit (10a) incorporated in the CPU (10) to output the down valve. The operation of (W) is prohibited. Therefore, the rotary work by the working depth control is performed extremely smoothly, and at the same time, when the work mode other than the depth work mode is selected, the operation command from the down valve cut control unit (10a) is not output, It can operate as a normal down valve (W).

An example of the operating procedure will be described with reference to the flow chart in FIG. When the work mode is switched to the depth work mode by step, the operation of the down valve (W) is prohibited by an operation command from the down valve cut control unit (10a) incorporated in the CPU (10) ( Step). In that case, the lift arm (3) moves up and down until the set value by the tiller depth setting machine (I2) and the detected value by the tiller depth sensor (S2) match, and the rotary work is performed by smooth tiller depth control. . (Step) At this time, in the step, since the use of the down valve (W) is prohibited in the step, the down valve solenoid of the step is not excited, and only the down proportional solenoid valve (14) is used. Is excited (step) and the lift arm (3) descends, or the lift arm (3) rises in step, and when it is neutral, the proportional solenoid valve stops (step).

Further, as shown in the control circuit diagram of FIG. 4 and the flow chart of FIG. 5, between the working depth sensor (S2) and the CPU (10),
Connect the signal line (X) for distinguishing whether the tilling depth sensor (S2) is attached or not attached. When the depth working mode is selected and the tilling depth sensor (S2) is not attached, the descent valve (W) can be operated. If the tilling depth sensor (S2) is attached, As described above, the operation of the down valve (W) is prohibited. In that case, the rotary operation by the tilling depth control is stably performed. Therefore, in the case of a work mode other than the depth work mode, such as position or draft control, the down valve (W) is used.
It is extremely convenient because you can work with permission to use. Thus, the operation procedure of them can be fully understood by referring to the flow chart of FIG.

〔The invention's effect〕

The present invention is a tractor having a plurality of working modes including a depth working mode, as will be described in detail with reference to one embodiment. In the lift cylinder attached to the tractor when the depth working mode is selected. Since the operation of the valve that can switch to a state in which the amount of oil flowing from the lift cylinder to the tank is increased by the internal pressure of the valve is prohibited, rotary work based on the plowing depth control can be performed stably, and Stable tilling work can be avoided, and
When a work mode other than the depth work mode, for example, a work mode by position or draft control is selected, the smooth operation of the valve can be expected by permitting the operation of the valve.

[Brief description of drawings]

1 shows an embodiment of the present invention, FIG. 1 and FIG. 4 are control circuit diagrams, FIG. 2 is a side view of a tractor to which a ground work implement is attached, and FIGS. 3 and 5 are flow charts. . Explanation of code (1) …… Tractor, (2) …… Ground work machine (3) …… Lift arm, (4) …… Lift rod (5) …… Lower link, (6) …… Toplink (7)… … Work machine connection link, (8) …… Lift cylinder (9) …… Hydraulic lifting mechanism, (10) …… CPU (10a) …… Down valve cut control section (11) …… Rise drive section, (12 ) …… Driving part for lowering (13) …… Proportional solenoid valve for raising (14) …… Proportional solenoid valve for lowering (15) …… Pump, (I1) …… Position lever (I2) …… Setting the working depth Vessel, (S1) …… lift arm angle sensor (S2) …… deep depth sensor, (T) …… work mode switching panel (W) …… down valve, (X) …… signal line

Claims (1)

(57) [Claims] 1. A tillage depth sensor for detecting the tilling depth of a ground working machine, which is provided so as to be vertically movable by a hydraulic lifting mechanism,
It has a plurality of working modes including a depth working mode in which the lifting operation is performed according to the difference between the value detected by the working depth sensor and the value set by the working depth setter, and the lift is used. In a tractor having a valve capable of switching to a state in which the amount of oil flowing from the lift cylinder to the tank is increased by the internal pressure in the cylinder, when the depth working mode is selected, the valve is removed from the lift cylinder. A descent valve cut device for a ground work machine, characterized in that a control unit is provided in the CPU so as not to switch to a state in which the amount of oil flowing to the tank is large