JPH08149903A - Engine-controlling structure in tractor - Google Patents

Abstract

PURPOSE: To provide an engine-controlling structure in a tractor capable of preventing the engine from a stalling, maintaining a safety on making a turn and traveling on a road at an usual speed in spite of the state of lifting up a working machine for traveling on the road by providing a changeover switch for changing the automatic controlling device in either one of the state of working or not working. CONSTITUTION: This engine-controlling structure in a tractor comprises providing a changeover switch which is constituted as only when a butt switch AW1 constituted to be 'off' on cutting off the electric source of the tractor, is 'on', the number of rotation of the engine is reduced after a prescribed time lag on setting a hydraulic lifter switch SW2 to 'lift up' side, for changing an automatic controlling device which is constituted to perform a control to reduce the number of rotations of the engine on detecting the lifting up of the lifter of the working machine, to either one of the state of working or not working. Furthermore, the operating response rate of the above automatic controlling device is preferably set to be slow at the lifting up of lifter and fast at the lowering down thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control structure for a high-speed work vehicle type tractor for safety at the time of turning or for traveling on the road.

[0002]

2. Description of the Related Art Conventionally, in a tractor, the engine speed is determined in proportion to the setting of an accelerator lever, and even when turning a headland, a target speed is obtained by operating the accelerator lever. However, in recent years, in high-speed work type tractors that have become able to perform reliable work while traveling at high speeds, turning on a headland with the accelerator setting is too fast and dangerous, so lower the engine speed when turning. It came to have a control means to make it. (For example, the actual Kaihei 6-1
This is like the technique described in Japanese Patent No. 3930. ) Among them, a detection switch is provided for discriminating the ascending / descending state of the lifting device for mounting the working machine. When the switch detects the ascending, it is considered that the headland is turning and the engine speed is automatically changed. It is known that a tractor is provided with an automatic control device that reduces the power consumption.

[0003]

However, if the engine speed decreases automatically every time the lifting device rises,
Even when traveling on the road with the work implement raised, the engine speed is low and the vehicle can only travel at low speeds. Alternatively, when working at a low speed, there is also a problem that the speed at the time of headland turning becomes extremely slow.

In order to solve such a problem, it is conceivable to provide a switch for releasing or not releasing the above-mentioned automatic control device, but this switch is a lock type which is not released even if the power of the tractor is turned off. In this case, the engine output does not rise even though the automatic control device is operating when the power is turned off, the work is stopped with the lifting device raised, and the power is turned on again to start the work. I mistakenly think that I will raise the engine speed to the maximum. Furthermore, if you notice it on the way and switch it off, the engine speed will suddenly increase, which is dangerous.

Further, when the reaction speed of operation of the automatic control device, that is, when the raising / lowering device is raised, the engine speed reduction control is too fast (for example, at the same time as the raising / lowering device is raised), the engine speed is lowered. As a result, the rise speed becomes slower due to lowering of the work speed, which may cause the work machine to turn regardless of the state of being left in the soil. Conversely, when lowering the lifting device, the engine speed If the start of the rising control is slow, the engine speed may be slow even though the work machine is in the working state, and the engine may stall.

[0006]

The present invention uses the following means in order to solve the above problems. That is, in a tractor configured to perform control for lowering the engine speed when it is detected that the lifting device for mounting the working machine rises, a changeover switch for switching the automatic control device between an operating state and a non-operating state. Was set up.

Further, the change-over switch is configured to be released when the power of the tractor is turned off so that the automatic control device is inactivated.

Further, the operating reaction rate of the automatic controller is
It was set so that the lifting device is slower when it goes up and faster when it goes down.

[0009]

By setting the automatic control device of the engine speed to the non-operating state by the changeover switch, even if the working machine is raised while traveling on the road or the like, the control of lowering the engine speed does not occur and the normal control is performed. It is possible to drive on the road depending on the speed.

Further, since the changeover switch releases the power supply of the tractor when the power supply is turned on again, the automatic control device is in a non-operating state.
Even if the work machine is rising, it is at a normal running speed,
Even if the driver notices that he / she turns on the changeover switch and operates the automatic control device, it is safe because the traveling speed is switched from the high speed state to the low speed side.

Further, in the automatic control device, by delaying the start timing of the decrease of the engine speed at the start of turning, the ascending speed of the elevating device can be increased without decreasing and the working machine can be operated. The engine speed decreases after rising and above the soil, and the turning state can be entered. Further, at the end of turning, the engine speed starts to rise quickly, so that the engine speed is sufficient until the working machine descends into the soil, and engine stall is prevented.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the structure of the present invention will be described based on the embodiments shown in the accompanying drawings. FIG. 1 is a side view of a tractor, FIG. 2 is a plan view of the same, FIG. 3 is a basic flowchart of automatic engine control accompanying headland turning, and FIG. 4 is a flowchart of the same case where the headland switch SW1 is an unlock type. , Fig. 5 shows that headland switch SW1 is switched from ON to OFF
When the switch is turned on, the headland switch SW1
FIG. 6 is a flowchart showing a safety structure of engine control configured to cancel the operation. FIG. 6 is a diagram illustrating a structure in which when the headland switch SW1 is ON, the start of lowering the engine speed is delayed when the hydraulic lifting switch SW2 is raised. It is an automatic control flowchart figure of an engine accompanying turning.

The overall construction of the tractor will be described with reference to FIGS. 1 and 2. A bonnet 1 in which an engine E is installed is arranged at a front portion of a vehicle body on which front and rear wheels FW and rear wheels RW are suspended, and a cabin 2 is mounted from a rear portion of the bonnet 1 to a rear end of the vehicle body. Further, from the rear end of the vehicle body to the rear, there is a lifting device for mounting a working machine that can be lifted and lowered by hydraulic pressure.
A point-link hydraulic lift 3 is provided in a protruding manner, and a working machine such as a rotary R as shown in the figure can be mounted on the rear end of the hydraulic lift 3.

In the cabin 2, a front column 4 having a handle 5 and the like projecting from the front portion thereof and a seat 6 at the rear portion thereof are provided.
And an operation panel 7 is arranged on the side of the seat 6. In the front column 4, an accelerator lever AL is provided so as to project, and an accelerator sensor AS for detecting the operation amount of the accelerator lever AL is arranged in the rear part of the bonnet 1. Further, a fuel injection pump P is provided in the bonnet 1, and automatic control such as adjusting the injection amount of the fuel injection pump P based on the switching of a hydraulic pressure elevating switch SW2 described later is performed. A controller C1, a so-called electronic governor, is arranged at the forefront part in the bonnet 1.

On the other hand, a hydraulic lift control controller C2 is provided inside the operation panel 7 in the cabin 2, and a hydraulic lift switch SW2 for raising or lowering the hydraulic lift 3 is provided on the upper surface thereof. There is provided a headland switch SW1 which is a switching switch for switching the operation of automatic control for controlling the engine speed based on the switching of the hydraulic lifting switch SW2.

This tractor is a high speed working type,
While traveling at high speed, the work pitch of the work equipment is also made faster, so that ground work can be completed in a short time. And
In a high-speed working state, when the headland turns, the engine speed can be controlled based on the detection of switching of the hydraulic lift 3 that is raised during the headland turn so that the traveling speed can be reduced to a safe traveling speed. This automatic control operates only when the headland switch SW1 is turned on.

The basic flow of automatic engine control associated with the turning of the headland will now be described with reference to FIG. First, when the headland switch SW1 is turned off, the engine is not automatically controlled based on the elevation of the hydraulic lift 3, and the vehicle travels only at a speed based on the normal operation amount of the accelerator lever AL. That is, the engine rotation speed is always the rotation speed (AR) corresponding to the accelerator operation amount. For example,
At the time of traveling on the road, the hydraulic lift 3 is raised and the working machine is raised, so that a sufficient traveling speed cannot be obtained if the engine speed remains low. Further, when the ground work is performed at a low speed, if the engine speed is reduced when turning the headland, the speed will be extremely slow.
Therefore, when traveling on the road or working on the ground at a low speed, it is preferable to turn off the headland switch SW1 and travel only by adjusting the speed based on the normal operation amount of the accelerator lever AL.

For high-speed work, first, the headland switch SW1 is turned on, and the automatic control of the engine speed based on the switching of the hydraulic lift switch SW2 is activated. If the hydraulic lifting switch SW2 is set to the "up" side for headland turning, the engine control controller C1 operates to reduce the injection amount of the fuel injection pump P, thereby lowering the engine speed. The engine speed after the decrease is, for example, as shown in FIG. 3, an intermediate value between the engine speed (AR) corresponding to the detected amount of the accelerator sensor AS and the engine idle speed (IR) {(AR-IR) × 1. / 2 + IR}
And so on, and others, {(AR-IR) × 1 /
3 + IR}, {(AR-IR) × 2/3 + IR}, etc.

When the hydraulic lift switch SW2 is set to the "down" side in order to set the working machine in the soil after the headland turning is completed, the accelerator sensor AS is set in the engine control controller C1 so that high speed work can be performed again. The injection amount returning operation of the fuel injection pump P is performed so that the engine speed (AR) corresponding to the detected amount of is obtained. Then, when the hydraulic lift switch SW2 stops rising or falling, for example, when turning on a headland, it is possible to turn while lowering the speed, and during ground work, the accelerator lever AL that was returned when the work machine was grounded. The engine speed is maintained as it is so that the work can be performed at a speed proportional to the operation amount.

As described above, in the tractor configured to activate the automatic control of the engine speed based on the switching of the hydraulic lift switch SW2 only when the headland switch SW1 is turned on, the structure for releasing the headland switch SW1 is next. Will be described with reference to FIGS. 4 and 5. First, the headland switch SW1 may be a lock-type switch that is held even when a key switch for turning on / off the power of the tractor is turned off. In this case, for example, with the headland switch SW1 turned on, even if the key switch is turned off for a break or the like, if the key switch is turned on again, the engine speed control when turning the headland can be automatically performed. It is in a state, and you can immediately start high-speed work.

However, the key switch is turned on for a break or the like.
In the case of FF, the work machine is usually in a raised state, and when the work is started again, forgetting that the headland switch SW1 is on, and that the desired speed cannot be obtained. Thinking about it, it is possible to force the engine speed to rise. Therefore, as shown in FIG. 4, the headland switch SW1 is configured to be turned off, that is, released when the key switch is turned off, that is, when the power of the tractor is turned off.

When the headland switch SW1 is kept on and the working machine is raised to start running on the road and the accelerator lever AL is used to increase the speed to some extent and then the headland switch SW1 is turned off, the speed is rapidly increased. Is dangerous. Therefore, even if the headland switch SW1 is turned off, unless the speed is lowered to some extent, the operation for returning the engine speed to the accelerator sensor equivalent amount is not performed. That is, as shown in FIG. 5, when the headland switch SW1 is turned on in advance when the headland switch SW1 is turned off, the detection amount of the accelerator sensor AS is detected, and the engine speed is close to the idle speed. Only when the engine speed is equal to or lower than the engine speed (IR '), the operation for returning to the engine speed (AR) corresponding to the detected amount of the accelerator sensor AS is performed. In this way, it is possible to prevent the risk of falling due to a sudden start.

Next, referring to FIG. 6, the reaction speed control of the engine control accompanying the raising and lowering of the working machine will be described. In the case where automatic control is performed to reduce the engine speed during headland turning, if the engine speed decreases, the hydraulic pump pressure for operating the hydraulic lift also decreases, so the lifting speed of the hydraulic lift 3 decreases. To do. If the rising speed of the working machine before the start of turning is slow, the working machine may be present in the soil even after turning and may hinder the turning. Therefore, when the hydraulic lift switch SW2 is set to the "up" side, the engine speed is reduced after a certain time, for example, 0.5 second in the embodiment shown in FIG. 6, {(AR-I
R) × 1/2 + IR} operation is performed. On the contrary, when the hydraulic lift switch SW2 is turned to the "down" side after the turning is completed, the hydraulic lift 3 is lowered, but the hydraulic lift 3 is lowered immediately by performing an operation of returning the engine speed to the original value (set to AR). The engine speed is increased, and the work machine is set in the soil with a sufficient engine speed to prevent engine stalling. That is, the control reaction speed of the engine speed is slowed only when the work implement is raised at the start of turning.

The above is the description of the automatic control structure of the engine speed associated with the turning of the high-speed working tractor.
Next, an embodiment of the attitude control mechanism of the working machine such as the rotary R will be disclosed. On the work machine, in order to hold it in a horizontal state or at a preset constant inclination angle,
An actuator such as a hydraulic cylinder is provided, and a setting device for setting which angle is to be held and a tilt sensor for detecting the tilt angle of the working machine are provided. Then, when the deviation between the set value of the setting device and the detection angle of the tilt sensor is detected, for example, an output signal for opening and closing the hydraulic cylinder valve is transmitted at a constant frequency, and the actuator such as the hydraulic cylinder is operated, The work machine is held in the desired posture.

If the actuator for attitude control reacts excessively, it will operate unnecessarily and can no longer maintain a constant attitude. Therefore, for example, the frequency of the signal for opening and closing the hydraulic cylinder valve will be kept below a certain frequency, and the actuator will react to some extent. I'm slowing down. In addition, the inclination sensor is provided with a low-pass filter to replace the uneven frequency of the field with the frequency and to pass only the detection signal of a certain frequency or less,
If the irregularity frequency is too high and the detection signal of the irregularity frequency is higher than the break frequency of the low-pass filter, the frequency is truncated and the irregularity frequency is replaced with a certain frequency or less, that is, the dead zone is to some extent. I try to make it wider and make it react.

However, in a substantially flat field, even if the reaction speed is slow to some extent or the dead zone is wide, there is an inclination control effect, but in the field where the uneven width is large, that is, the height difference of the unevenness of the field surface is large. , The reaction becomes relatively slow, and the posture control becomes insufficient. As a result, in the case of plough plowing, for example, the leveling is not sufficient, and two or more overlapping operations are inevitable.

Therefore, in such a case where the uneven width is large, the reaction of the actuator is made sensitive. The size of the concavo-convex width is to see the deviation between the set value of the setter and the detection value of the tilt sensor, and based on this, for example, the frequency of transmission of the output signal for opening and closing the hydraulic cylinder valve can be made dense. Conceivable. Also, a method of changing the break frequency of the low-pass filter in the tilt sensor can be considered. Table 1 is a table in which the break point frequency is set corresponding to the deviation width between the set value of the setter and the detection value of the tilt sensor. The larger the deviation width, that is, the larger the uneven width, the higher the break point frequency. The height is increased so as to cope with the more frequent unevenness. In this way, it is possible to configure the attitude control device of the working machine that can adjust the reaction speed according to the uneven width of the field.

[0028]

[Table 1]

[0029]

Since the present invention is configured as described above, it has the following effects. That is, in the tractor configured as described in claim 1 so as to control the engine speed to be lowered when it is detected that the lifting device for mounting the working machine rises, whether the automatic control device is in an operating state or a non-operating state. Since the changeover switch for changing over is provided, even if the working machine is raised while traveling on the road or the like, control for lowering the engine speed does not occur and traveling on the road at a normal speed is possible.

Further, according to the second aspect of the invention, the changeover switch is configured to be released when the power of the tractor is turned off so as to make the automatic control device inoperative. Therefore, when the power is turned on again, the automatic control device is turned off. Is not operating, and the traveling speed is normal even if the work implement is moving up. Even if the driver notices that he has turned on the changeover switch and activated the automatic control device, the traveling speed is high. It is safe because it switches from the state to the slower one.

Further, as described in claim 3, since the operation reaction speed of the automatic control device is set so as to be slow when the lifting device is raised and is made fast when it is lowered, the lifting speed of the lifting device is lowered at the start of turning. It can be raised without doing so, and the engine speed can be lowered after the working machine is raised to be above the soil and the turning state can be entered. Further, at the end of turning, the engine speed starts to rise quickly, so that the engine speed is sufficient until the working machine descends into the soil, and engine stall is prevented.

As described above, the safety, operability, and work efficiency of the high-speed work type tractor having the engine control device for turning can be improved.

[Brief description of drawings]

FIG. 1 is a side view of a tractor.

FIG. 2 is a plan view of the same.

FIG. 3 is a basic flowchart of engine automatic control accompanying headland turning.

FIG. 4 is a flowchart diagram when the headland switch SW1 is also of an unlock type.

FIG. 5 is a flowchart showing an engine control safety structure configured to release the headland switch SW1 when the headland switch SW1 is turned from ON to OFF at a certain speed or less.

FIG. 6 is a flowchart of an automatic control flow chart of an engine associated with headland turning, which is configured to delay the start of engine speed reduction when the hydraulic lift switch SW2 is raised when the headland switch SW1 is ON.

[Explanation of symbols]

 E Engine P Fuel injection pump AL Accelerator lever AS Accelerator sensor C1 Engine control controller C2 Hydraulic lift control controller SW1 Headland switch SW2 Hydraulic lift switch

Claims (3)

[Claims] 1. A tractor configured to perform control for lowering an engine speed when it detects that a lifting device for mounting a work implement rises, in order to switch its automatic control device between an operating state and a non-operating state. An engine control structure for a tractor, which is provided with a changeover switch. 2. The tractor engine control structure according to claim 1, wherein the changeover switch is configured to be deactivated when the power of the tractor is turned off to deactivate the automatic control device. Engine control structure of the tractor. 3. The engine control structure for a tractor according to claim 1, wherein the operating reaction speed of the automatic control device is set to be slow when the lifting device is rising and fast when it is falling. Control structure.