JP3732373B2 - Tractor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of a tractor provided with automatic tilling depth control means and engine rotation load control means.
[0002]
[Prior art]
In general, this type of tractor is provided with a plowing depth automatic control means for automatically raising and lowering the working unit based on a detection value of a plowing depth sensor that detects the working depth of the working unit. Even if the load is maintained, the load on the working unit varies depending on the field conditions such as the soil quality, and therefore there is a possibility that inconvenience such as engine stall may occur based on the overload of the working unit.
[0003]
[Problems to be solved by the invention]
Therefore, an engine rotational load control means for retracting and raising the working unit by a predetermined amount in response to a decrease in the engine rotational speed is provided, and the engine rotational load control is performed in combination with the plowing depth automatic control, thereby causing an overload. Although it has been proposed to prevent engine stall, etc., in the conventional system, the retreated and lifted working part was immediately lowered to the set working depth of the automatic working depth control, so the engine speed decreased again. Therefore, there is a high possibility that the working part is retracted and raised, and therefore, a hunting phenomenon in which the working part repeats raising and lowering occurs, resulting in inconvenience that working accuracy and stability are lowered.
[0004]
[Means for Solving the Problems]
The present invention has been created in view of the above circumstances and has been created for the purpose of solving these problems. The invention of claim 1 is directed to a working unit connected to a traveling machine body so as to be movable up and down, and the work. An engine speed sensor that detects an engine speed that changes in accordance with the work load of the section, a working depth sensor that detects a working section plowing depth based on the rear cover posture of the working section, and a detection value of the plowing depth sensor Based on the automatic tilling depth control means for automatically controlling the working depth based on the working section, the working depth automatic control is temporarily stopped when the engine speed has decreased to the retreat increase judgment speed , and the working section is located. A tractor having an engine rotational load control means for evacuating and lifting a fixed amount, and determining a change in the engine speed after the working part is evacuated and lifted to the tractor, and if the decrease in the engine speed does not stop, work again Part When the engine speed has increased to the specified speed, the tilling automatic control is resumed when the engine speed has increased to a predetermined speed, and when the engine speed has not risen and the stable state has been maintained, return to the automatic working depth control. The tractor is characterized in that means is provided for restricting and waiting the working part at the retracted and raised position . In other words, when the engine rotation is stable after the working unit is retracted and lifted, the working unit is placed in the retracted and raised position, so that it returns to automatic tilling control immediately after the working unit is retracted and lifted. Therefore, it can be avoided that the engine speed decreases again and the working part is retracted and raised, and as a result, it is possible to suppress the occurrence of the hunting phenomenon in which the working part repeats rising and lowering, thereby improving the working accuracy and stability. it can.
According to a second aspect of the present invention, in the tractor according to the first aspect, a single control mode for executing the engine rotational load control alone and a composite control mode for executing the tilling depth automatic control and the engine rotational load control in combination are set. In doing so, the tractor is characterized in that it is provided with mode automatic switching means for automatically switching between the single control mode and the composite control mode based on the rear cover posture of the working unit. That is, since the switching operation between the single control mode and the composite control mode is not required, it is possible not only to reduce the operation effort of the operator, but also to prevent a reduction in work accuracy due to erroneous mode switching.
According to a third aspect of the present invention, in the tractor according to the first aspect, the revolving increase determination rotational speed is calculated as a rotational speed having a predetermined ratio with respect to the reference rotational speed with the engine rotational speed when no load is applied as the reference rotational speed. It is a tractor characterized by being made. In other words, since the engine speed at which the working unit retreats and rises is set at a constant ratio from the engine speed at the time of no load, engine stall can be prevented based on appropriate retreat rise even during low-speed work.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Next, one embodiment of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 denotes a traveling machine body of a tractor, and a working unit 3 is connected to a rear portion of the traveling machine body 1 via a lifting link mechanism 2 so as to be lifted and lowered. The working unit 3 moves up and down with the hydraulic lifting and lowering operation of the lift arm 4 that holds the lifting and lowering link mechanism 2, and these basic configurations are all conventional.
[0006]
The working unit 3 includes a tilling shaft 6 to which a plurality of tilling claws 5 are attached, a tilling cover 7 that covers the top of the tilling shaft 6, a rear cover 8 that is provided at the rear end of the tilling cover 7 so as to be swingable up and down, A plowing depth sensor 9 for detecting the plowing depth of the working unit 3 based on the swing angle of the rear cover 8 is provided. In other words, the working unit 3 of the present embodiment is a rotary working machine that plows the farm field based on the rotational drive of the tilling claws 5 and leveles the tilled soil with the rear cover 8. In the rotary working machine, for example, There is a case where the rear cover 8 is held in a flipped-up posture, as in the case of a raising work performed by attaching a raising attachment (not shown) behind the tilling claw 5.
[0007]
Reference numeral 10 denotes a control unit provided in the traveling machine body 1, and the control unit 10 is configured by using a microcomputer (including a CPU, a ROM, a RAM, and the like). A depth sensor 9, a lift arm sensor 11 for detecting the arm position of the lift arm 4, a position sensor 13 for detecting the lever position of the position lever 12, an automatic control switching volume 14 for switching automatic control, and "plowing depth automatic control" to be described later Through a predetermined input interface circuit, a working depth setting volume 15 for setting the target working depth, an engine speed sensor 16 for detecting the engine speed, a throttle sensor 17 for detecting the position of a throttle lever (not shown), and the like. On the other hand, on the output side, the lifting solenoid 18a of the lift arm electromagnetic switching valve 18 and the lower Solenoid 18b, automatic tilling depth control lamp 19 for displaying "plowing depth automatic control" status, engine rotational load control lamp 20 for displaying "engine rotational load control" status, etc. are connected via a predetermined output interface circuit. Has been. That is, the control unit 10 performs “position control” for raising and lowering the working unit 3 (lift arm 4) in accordance with the deviation of the lift arm sensor value from the position sensor value, and the deviation of the tilling depth sensor value from the tilling depth setting volume value. "Plowing depth automatic control" that controls the working unit 3 to move up and down according to the "engine rotation load control", "plowing depth automatic control" and " “Mix control” for executing “engine rotation load control” in combination, “mode switching control” for switching each control, and “engine rotation” for setting the engine speed for retracting and raising the working unit 3 in the “mix control”. Control program such as “number setting”, and hereinafter, “mix control”, “mode switching control” and “engine speed setting” which are the main parts of the present invention. It is described with reference to a flowchart of control procedure ".
[0008]
The “mode switching control” first determines ON / OFF operation states of “plowing depth automatic control” and “engine rotation load control” based on the operation position of the automatic control switching volume 14 and the like. When it is determined that “automatic control” is in the OFF operation state, the execution state of “plowing depth automatic control” is turned off, and the plowing depth automatic control lamp 19 and the engine rotation load control lamp 20 are turned off. In addition, when it is determined that “plowing depth automatic control” is in the ON operation state and “engine rotation load control” is in the OFF operation state, the execution state of “plowing depth automatic control” is turned ON and the plowing depth The automatic control lamp 19 is turned on. Further, when it is determined that both “automatic tilling depth control” and “engine rotation load control” are in the ON operation state, in principle, the execution state of “mix control” is turned on, and the tilling depth automatic control lamp 19 and Although the engine rotation load control lamp 20 is turned on, it is determined that the rear cover 8 is held in the flip-up position even when both the “plowing depth automatic control” and the “engine rotation load control” are in the ON operation state (plowing depth). In the case of (sensor value> judging judgment value), “engine rotation load control” is executed alone and the engine rotation load control lamp 20 is lit. In other words, the plowing depth sensor value is invalid in the state where the rear cover 8 is held in the flip-up posture. Therefore, the execution of “mix control” using the plowing depth sensor value is restricted, and “engine rotation load control” is performed independently. It is supposed to run. By the way, during tillage work, there is a possibility that the plowing depth sensor value exceeds the jumping judgment value and makes an erroneous judgment. However, in this embodiment, even if the provisional plowing depth sensor value exceeds the jumping judgment value, When it is determined that plowing work is in progress (when the lift arm is in the lowered state and the operation is not started), the control mode is not switched, so that it is possible to prevent control switching based on an erroneous determination. Yes.
[0009]
Further, “engine speed setting” stores the engine speed in an unloaded state as a reference speed when the lift arm 4 is lifted, and at a predetermined ratio (for example, 80%) with respect to the reference speed. The number of revolutions is calculated, and the number of revolutions is set as a retreat increase determination revolution number. That is, the engine speed at which the working unit 3 is retracted and raised is set at a constant ratio from the engine speed at the time of no load, so that engine stall can be prevented based on the appropriate lift and rise even during low-speed work. It is like that.
[0010]
Further, the “mix control” monitors the engine speed while executing the “plowing automatic control” in the mix control mode, and when the engine speed has decreased to the retreat increase determination speed, The “plowing depth automatic control” is temporarily stopped and the working unit 3 (lift arm 4) is retracted and raised by a predetermined amount. However, even after the working unit 3 is retracted and raised, fluctuations in the engine speed are monitored. If the reduction in engine speed does not stop even when the working unit 3 is retracted and raised, the working unit 3 is again retracted and raised by a predetermined amount, while when the engine speed has increased to the predetermined rotational number, The “plowing depth automatic control” is resumed, and the work unit 3 is lowered to the set plowing depth of “plowing depth automatic control” accordingly, but even if the working unit 3 is retracted and raised, the engine speed does not increase. When the stable state is maintained, the return to “plowing depth automatic control” is restricted, and the working unit 3 is made to stand by at the retracted and raised position. Accordingly, it can be avoided that the engine speed decreases again and the working unit 3 is retracted and lifted up, like the case where the working unit 3 is retreated and immediately returned to "plowing depth automatic control". It is possible to improve the working accuracy and stability by suppressing the occurrence of a hunting phenomenon in which 3 repeats rising and lowering.
[0011]
In the configuration as described above, the working unit 3 that is connected to the traveling machine body 1 so as to be movable up and down, the engine rotation sensor 16 that detects the engine speed that changes in accordance with the work load of the working unit 3, and the work The working depth sensor 9 that detects the working section plowing depth based on the rear cover posture of the section 3, “plowing depth automatic control” that controls the working section 3 to move up and down based on the detection value of the working depth sensor 9, and the engine speed Although but is intended and a "engine load control" by a predetermined amount retracted raised working unit 3 in response to the decrease, it is determined the engine rotation fluctuation after being raised retracted working unit 3, and the work If the decrease in engine speed does not stop even when the part 3 is retracted and raised, the working part 3 is again retracted and raised by a predetermined amount. On the other hand, if the engine speed has increased to the predetermined speed, Resumed `` control '' Accordingly, the working unit 3 is lowered to the set tilling depth of “plowing depth automatic control”, but when the working unit 3 is retracted and raised, the engine speed does not rise and the stable state is maintained. Is configured to restrict the return to the “plowing depth automatic control” and to make the working unit 3 stand by at the retreated and raised position. For this reason, it can be avoided that the engine speed decreases again and the working unit 3 is lifted and lifted again, as in the case of immediately returning to the “plowing depth automatic control” after the working unit 3 is lifted and lifted. It is possible to improve the working accuracy and stability by suppressing the occurrence of the hunting phenomenon in which the portion 3 repeats rising and lowering.
[0012]
In addition, when setting the engine rotation load control mode for executing “engine rotation load control” alone and the mix control mode for performing “plowing depth automatic control” and “engine rotation load control” in combination, 3 is equipped with a “mode switching control” that automatically switches between the engine rotational load control mode and the mix control mode based on the rear cover posture of FIG. 3, so that the switching operation between the engine rotational load control mode and the mix control mode becomes unnecessary. As a result, not only the operator's operation effort can be reduced, but also a reduction in work accuracy due to an erroneous mode change can be prevented.
[0013]
In addition, the “engine rotation load control” uses the engine rotation speed when there is no load as a reference rotation speed, and when the engine rotation speed decreases to a predetermined ratio with respect to the reference rotation speed, the working unit 3 is retreated and raised. The engine stall can be prevented based on an appropriate retreat rise even during low rotation work.
[Brief description of the drawings]
FIG. 1 is a side view of a tractor.
FIG. 2 is a block diagram showing input / output of a control unit.
FIG. 3 is a flowchart showing “mode switching control”;
FIG. 4 is a flowchart showing “engine speed setting”;
FIG. 5 is a graph showing an effect of “engine speed setting”;
FIG. 6 is a flowchart showing “mix control”;
FIG. 7 is a timing chart showing the operation of “mix control”.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Traveling machine body 3 Working part 8 Rear cover 9 Plowing depth sensor 10 Control part 16 Engine rotation sensor

Claims (3)

A working unit connected to the traveling machine body so as to be movable up and down, an engine speed sensor that detects an engine speed that changes in accordance with a work load of the working unit, and a working unit working depth based on a rear cover posture of the working unit. A plowing depth sensor to be detected , a plowing depth automatic control means for automatically controlling the plowing depth of the working unit based on a detection value of the plowing depth sensor, and in response to the engine speed being reduced to the revolving increase determination speed A tractor comprising engine rotation load control means for temporarily stopping plowing depth control and retracting and raising the working unit by a predetermined amount, and determining the engine rotation fluctuation after the working unit is retracted and raised by the tractor. and, the increased predetermined amount retracting the working portion again when the reduction in the engine rotational speed does not stop, to resume Kofuka automatic control when the engine speed has increased to a predetermined rotational speed, increases the engine speed Tractor, characterized in that a means for waiting retracted raised position the working part to regulate the return to Kofuka automatic control when maintaining the stable state without.   The tractor according to claim 1, wherein a single control mode for executing engine rotational load control alone and a composite control mode for executing combined tilling depth automatic control and engine rotational load control in combination are set. A tractor comprising automatic mode switching means for automatically switching between a single control mode and a composite control mode based on a posture. The tractor according to claim 1, wherein the retraction increase determination rotation speed is calculated as a rotation speed at a predetermined ratio with respect to the reference rotation speed, with the engine rotation speed when no load is applied as the reference rotation speed. Characteristic tractor.

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