JP3620458B2 - Auto lift device for tractor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tractor autolift device.
[0002]
[Prior art]
When a working machine such as a rotary or a plow is connected to the rear part of the tractor, it is necessary to raise the working machine to a predetermined height in order to prevent the working machine from being dragged when turning the machine body in the field.
[0003]
There is also a tractor equipped with an auto-lift device that detects the rotation angle of the steering wheel and assumes that the aircraft has entered a turning state when the rotation angle exceeds a predetermined value, so that the work implement is automatically raised. Are known.
[0004]
[Problems to be solved by the invention]
The conventional autolift device automatically rises at a timing when the rotation angle of the steering wheel exceeds a predetermined value even in a dry paddy field and a wet paddy field. However, for example, in soft ground such as wet fields, the steering operation becomes heavy and the steering wheel may turn in the opposite direction. The operability of the apparatus was not good.
[0005]
[Means for Solving the Problems]
The present invention has been proposed to achieve the above object, and in the invention according to claim 1, a tractor including an autolift device that automatically raises the work implement in conjunction with the rotation operation of the steering wheel 32 is provided. in it, the tractor, a sensor 31 for detecting the rotation angle of the steering wheel 32 is provided, an increase determination condition by that the working machine on the detected value of the sensor 31, the rotational speed of the steering wheel 32 is greater than a predetermined value And when the rotation angle exceeds a predetermined value, the condition is assumed to work on a hard ground that automatically raises the work implement, and when the rotation angle of the steering wheel 32 exceeds a predetermined value, the work implement is automatically raised. set the judgment conditions assuming working in soft ground which, that it has switched freely configured by the mode switch the determination condition And auto lifting device of the tractor to symptoms.
[0006]
[Operation and effect of the invention]
According to the first aspect of the present invention, the rotation angle of the steering wheel is detected by the sensor 31, and the working machine is automatically raised by the detected value. At that time, the mode switch is used to set whether to work on hard ground or soft ground. Specifically, in the mode assuming the work on the hard ground, when the rotation speed of the steering wheel exceeds a predetermined value and the rotation angle exceeds the predetermined value, the work implement is automatically raised, and the work on the soft ground is performed. In the assumed mode, when the rotation angle of the steering wheel exceeds a predetermined value, the work implement is automatically raised. Thereby, a working machine can be automatically raised at the timing according to the hardness of the ground such as the wet field and the dry field.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a tractor 11. A clutch housing 13 is fixed to a rear portion of an engine 12, and a front mission case 15 and a rear mission case 16 are connected via a spacer case 14.
[0008]
Left and right brake pedals 17 and 18 are provided on the right side of the spacer case 14 and are pivotally mounted so that they can be independently depressed. Now, when the left brake pedal 17 is depressed, the brake rod 20 provided on the left side of the spacer case 14 is pulled by the rotation of the pedal shaft 19, and the left brake arm 21 is rotated forward to move the left rear. The wheel brake device 22 is activated.
[0009]
The left and right brake linkages are formed symmetrically. When the right brake pedal 18 is depressed, the brake rod 23 provided on the right side of the spacer case 14 is pulled, and the right brake arm 24 rotates forward. Then, the right rear wheel brake device 25 operates. The left and right rear axle housings 26 and 27 are provided with hydraulic actuators 28 and 29 for pressing the brake arms 21 and 24 forward, respectively.
[0010]
A rotation angle sensor 31 is provided on the steering shaft 30 to detect the rotation angle of the steering wheel 32. The controller 33 divides the rotation angle into three regions, a straight traveling region, an intermediate region, and a turning region, and determines which region the steering wheel 32 is rotating.
[0011]
FIG. 2 shows an example of the relationship between the rotation angle of the steering wheel 32 and each of the above-mentioned areas. The range of 45 degrees from the neutral position N of the steering wheel 32 is set as the straight traveling area A, and the neutral position beyond the straight traveling area A is shown. A range from N to 90 degrees on each of the left and right sides is defined as an intermediate area B. And after exceeding the intermediate area B, it is set as the turning area C.
[0012]
As shown in FIG. 1, a lift cylinder 34 is provided at the top of the rear mission case 16, and the left and right lift arms 35, 36 are rotated up and down by the expansion and contraction of the lift cylinder 34 and connected to the rear part of the tractor 11. A working machine (not shown) is formed to be raised and lowered to an arbitrary height.
[0013]
Next, an example of auto lift control will be described with reference to the flowchart of FIG. First, the detection value of each sensor and the operation state of switches are read (step 101). Then, it is determined whether or not the autolift control switch is turned on or off (step 102). When the switch is turned on, the process proceeds to step 103, and in which region the rotation angle of the steering wheel 32 is determined from the detected value of the rotation angle sensor 31 It is determined whether it is in. When the rotation angle of the steering wheel 32 is in the turning area, the routine proceeds to step 104, where it is determined whether or not the rotation angle has once returned to the straight area since the previous auto-lift.
[0014]
In step 104, if the auto-lift has not been performed once and if the rotation angle of the steering wheel 32 has once returned to the straight-ahead region since the previous auto-lift, the routine proceeds to step 105, where the lift cylinder 34 The lift arms 35 and 36 are pivoted upward by the extension of, and an automatic lift for automatically raising the work implement is performed.
[0015]
On the other hand, when the auto-lift control switch is turned off at step 102, or when the rotation angle of the steering wheel 32 is not within the turning range at step 103, or since the previous auto-lift at step 104, the steering wheel. If the rotation angle of the work has not returned to the straight-ahead region, the process proceeds to step 110 and the work implement is not automatically lifted.
[0016]
That is, the steering wheel 32 is rotated, and when the rotation angle is changed from the straight traveling region to the intermediate region, and further from the intermediate region to the turning region, the work implement is automatically lifted. In addition, when the work equipment is lowered after the auto lift is activated and the steering wheel rotates while maintaining the rotation angle in the turning region or in the intermediate region, the rotation angle varies between the turning region and the intermediate region. Even if there is, the auto lift is not performed, and the work machine is prevented from being raised unexpectedly by the fine operation of the steering wheel.
[0017]
FIG. 4 shows the main part of the autolift control according to the present invention, in which two modes are set for the operation of the autolift control, and the operation timing of the autolift is changed by switching the mode switch. First, the state of each sensor or switch is read (step 201), and it is determined whether the autolift control switch is on or off (step 202). When the auto lift control switch is off, the work machine is not automatically lifted (step 202 → 230). When the auto lift control switch is on, the operation state of the mode switch is read at step 203, and when the mode switch is in the strong position, the process proceeds to step 204.
[0018]
In step 204, the operation of the autolift is determined based on the detected values of both the rotation speed and the rotation angle of the steering wheel 32. That is, when plowing on a hard ground such as a dry paddy, the steering operation is smoothly performed, so that the rotation speed of the steering wheel 32 is fast. Therefore, when the rotation speed of the steering wheel 32 is equal to or higher than the predetermined value and the rotation angle is equal to or higher than the predetermined value, the auto lift is operated to automatically raise the work implement (step 205 → 206). When the rotation angle does not reach the predetermined value, the current height of the work implement is maintained without operating the auto lift (step 205 → 220).
[0019]
On the other hand, the mode switch is set to weak when plowing on soft ground such as wet fields. If so, the routine proceeds from step 203 to 210, and the operation of the autolift is determined based only on the detected value of the rotation angle of the steering wheel 32. That is, in soft ground such as wetlands, the steering operation becomes heavy, and the steering wheel may turn in the reverse direction. Therefore, the operation timing of the autolift is delayed, and the rotation angle of the steering wheel 32 reaches a predetermined value. If not, the position of the work implement is maintained at the current state without operating the autolift (step 210 → 220), and the autolift is operated when the rotation angle exceeds a predetermined value (step 210 → 206). .
[0020]
FIG. 5 shows still another embodiment of the auto lift control. When there is no steering operation for a certain time during the operation of the auto lift control, the rotational position of the steering wheel at that time is set to the neutral position. First, the state of each sensor or switch is read (step 301). When the autolift control switch is off, the work implement is not automatically lifted (step 302 → 330). If the auto lift control switch is on, it is determined in step 303 whether or not the work implement is in the lowered position. If the work implement is lowered, the process proceeds to step 304.
[0021]
In step 304, the change in the rotation angle of the steering wheel 32 is monitored. For example, when one wheel travels on uncultivated land and the other wheel travels on already cultivated land, the aircraft is traveled straight with the front wheel slightly turned to the uncultivated land. At this time, the steering wheel 32 is naturally held at the position rotated from the neutral position to one side, and the rotation angle does not change. If so, in step 305, the rotational position of the steering wheel 32 at that time is stored as a straight-ahead position, and then the process proceeds to step 306.
[0022]
On the other hand, when the rotation angle of the steering wheel 32 is changing, the process proceeds from step 304 to step 310, and when the change amount of the rotation angle is large and a certain time has elapsed, the aircraft is considered to be turning. In step 311, the original neutral position of the steering wheel 32 is stored as it is as a straight-ahead position, and then the process proceeds to step 306. Further, when the state where the change amount of the rotation angle is large is a short time, the process proceeds from step 310 to step 306.
[0023]
Thus, in step 306, the rotation angle of the steering wheel 32 from the newly stored rectilinear position is calculated, and when the rotation angle exceeds a predetermined value, the auto lift is operated to operate the work implement. It is automatically raised (step 307 → 308). On the other hand, when the rotation angle does not reach the predetermined value, the current height of the work implement is maintained without operating the autolift (step 307 → 320).
[0024]
In step 303, when the work machine is already in the raised position, the process proceeds to step 320 to maintain the current height of the work machine. Thus, for example, when the vehicle is traveling straight on with the steering wheel operated slightly to the mountain side during work on a sloping ground, auto-lift control is performed with the rotational position of the steering wheel at that time as the straight traveling position. Therefore, the auto lift comes to be performed at the same timing when the left and right rotation angle changes of the steering wheel are the same.
[0025]
It should be noted that the present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.
[Brief description of the drawings]
FIG. 1 is a side view of a tractor according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram showing a relationship between a rotation angle of a steering wheel and each region.
FIG. 3 is a flowchart showing an example of autolift control.
FIG. 4 is a flowchart showing a main part of the auto lift control according to the present invention.
FIG. 5 is a flowchart showing still another embodiment of autolift control.
[Explanation of symbols]
11 Tractor 31 Rotation angle sensor 32 Steering wheel 33 Controller 34 Lift cylinders 35 and 36 Lift arm A Straight running area B Intermediate area C Turning area

Claims (1)

In the tractor provided with an autolift device that automatically raises the work implement in conjunction with the rotation operation of the steering wheel 32 , the tractor is provided with a sensor 31 that detects the rotation angle of the steering wheel 32 . the increase determination condition by that the working machine on the detection value, the rotational speed of the steering wheel 32 becomes greater than a predetermined value, and the rotation angle is assumed to work in hard ground to automatically increase the working machine and equal to or greater than a predetermined value and determination conditions, the rotation angle of the steering wheel 32 is set to the determination condition is assumed to work in soft ground to automatically increase the working machine to be a predetermined value or more, switching freely by the mode switch the determination condition An auto lift device for a tractor characterized by comprising.

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