JPH0636644Y2 - Dashing prevention control structure for work vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a dashing prevention control structure for a work vehicle such as an agricultural tractor.

[Problems to be Solved by Prior Art and Invention] Generally, in this type of work vehicle, when the working part set at the upper limit position is lowered to the working height, for example, the working part is a cultivator. In this case, when the ground touches, the reaction force of excavation by the plowing blade acts and a forward force is exerted on the aircraft, which may cause the aircraft to undergo a so-called dashing action in which it is momentarily pushed forward strongly. Is dangerous.

Therefore, in order to avoid this, there is a method in which the descending speed of the working unit is reduced to the dashing prevention speed before the working unit is lowered to the working height, and the dashing prevention control is performed. However, the conventional dusting prevention control mechanism
Since the dashing prevention speed is constant, there is a disadvantage that a large speed change occurs when the descent speed at a high speed shifts to the dashing prevention speed, resulting in a large shock.

On the other hand, in order to avoid the occurrence of shock, it is also possible to reduce the descending speed at a constant reduction ratio and then make the duty ratio of the ON time to the descending solenoid constant to perform the anti-dusting control. If this is selected, the descending speed will change due to changes in the weight of the work equipment and changes in the oil temperature of the hydraulic mechanism, and stable work performance will not be obtained. It cannot be done.

[Means for Solving the Problem] The present invention was devised with the object of providing a dashing prevention control structure for a working vehicle capable of eliminating these drawbacks in view of the above circumstances. hand,
For lowering the working unit set to the upper limit position to the working height, a dashing prevention control mechanism is provided to reduce the descending speed to the dashing preventing speed before the working unit reaches the working height. In the vehicle, the anti-dashing control mechanism sets the anti-dussing speed mode to a deceleration control mode in which the descending speed is gradually reduced at the beginning of the anti-dashing control, and then a mode switching means for switching to the feed back control mode in which the descending speed becomes constant. The present invention is characterized in that a start position adjusting means for adjusting the start position of the dashing prevention control and a descending speed adjusting means for adjusting the descending speed in the feed back control mode are provided.

With this configuration, according to the present invention, the dashing prevention speed when the working unit descends from the upper limit position is gradually reduced at the beginning, and then the descent is performed at a constant speed by the feed back control. This is an attempt to solve the problem.

[Embodiment] Next, an 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 an agricultural tractor, and a rotary tilling type working section 2 is attached to a rear portion of the traveling machine body 1 via an elevating link mechanism 3. The working unit 2 is configured to move up and down by a lift arm 6 that swings in association with expansion and contraction operations of lift solenoids 4 and 5, which will be described later. Further, 7 is a position control lever provided on a fan 9 portion which covers the rear wheel 8.

Reference numeral 10 is a control unit arranged in a control unit formed in the fan 9 unit, and the control unit 10 is configured by using a member such as a micro computer. Position detection sensor 11 for detecting the lever set position of the lever 7, arm angle detection sensor 12 for detecting the swing angle of the lift arm 6, working depth setting device 13 and automatic working depth switching switch 14 arranged in the control unit, working section. The data from the input device group such as the tilling depth detection sensor 15 arranged in 2 is input. Then, the control unit 10 issues an ON-0FF control command to the solenoids 4 and 5 based on the input data to control the working unit 2 up and down as described later.

Next, the ascending / descending control procedure will be described based on a flow chart and a timing chart. Here for convenience,
The detection value of the position detection sensor 11 is set to the lever detection value A,
The detection value of the arm angle detection sensor 12 is defined as the arm detection value B, the setting value of the plowing depth setter 13 is defined as the plowing depth setting value C, and the sensing value of the plowing depth detection sensor 14 is defined as the plowing depth detection value D. This will be described below.

Now, regarding the control procedure, first, the key switch is turned on to start it, and after reading the necessary data, it is judged whether or not the position control lever 7 is set to the upper limit position, and YES is set as it is set. If the judgment is made, the mode is set to "work start", and if NO is judged otherwise, the next arm detection value B is not the lever detection value A without doing so. Is also large (B> A, the height of the working portion is higher than the lever set position), and if YES is determined as being large, it is outside the preset dead zone α. It is judged whether there is any. If YES is determined to be outside the range, it is further determined whether or not the automatic plowing depth switching switch 14 is set to the automatic plowing depth side, and NO is determined as not being set to the plowing depth automatic side. If the determination is made, an ON command is issued to the lowering solenoid 5 to control the lowering of the working unit 2 corresponding to the lever position of the position control lever 7. On the other hand, if the detected value A is larger than the detected value A by comparing the detected values A and B, and the judgment is NO, and this is outside the dead zone α, an ON command is issued to the ascending solenoid 4. Then, the work unit 2 is controlled to be raised. In any case, when the working unit 2 is located within the dead zone α, the "work start" is performed.
The mode is reset and the "working" mode is set, and an OFF command is issued to the solenoids 4 and 5 to maintain the height of the working unit 2.

On the other hand, in the control procedure,
When the determination is YES as 14 is set to the automatic working depth, the working depth setting value C is larger than the working depth detection value D (C> D, working depth of working unit 2). Is located higher than the set value). If NO is determined as being small, it is further determined whether this is outside the dead zone β, and if it is outside the range, an ON command is issued to the ascending solenoid 4. The working unit 2 is controlled to rise so as to be within the range of the dead zone β. Further, in the case of judging whether the values C and D are large or small, it is judged as NO because the plowing depth detection value D is larger,
It is judged whether or not this is outside the dead zone β,
If YES is judged as being out of the range, it is further judged whether or not the mode is set to the "work start" mode. When it is determined that the mode is not the "starting work" mode, that is, the "working" mode is NO, an ON command is issued to the descending solenoid 5,
The working unit 2 is controlled to descend so as to be within the range of the dead zone β.

On the other hand, when the YES determination is made because the mode is the "start of work" mode, the arm detection value B is lowered to the deceleration start value L or less set in advance as the position to start the dashing prevention control. It is determined whether or not the detection value B is smaller than the start value L (B <L). still,
The deceleration start value L is set so that it can be arbitrarily adjusted by adjusting the dashing start position setter 16, and a start position adjusting means is configured. And in the judgment,
If NO is judged as not descending to this position yet, the descending solenoid 5 is still operated.
An ON command will be issued to perform high-speed lowering control. If YES is determined because the vehicle has descended, it is determined whether the downward control in the deceleration control mode is completed. Here, the deceleration mode is a mode in which the duty ratio of the ON time gradually decreases from t ₁ to t _s and the descending speed is gradually decelerated. Then, in the present embodiment, whether or not the down control in the deceleration control mode is completed is determined by whether or not the duty ratio is t _s.
It can be adjusted by When it is determined that the descent in the deceleration control mode is completed, the dashing prevention speed mode is switched to the feed back control mode, and the descent control in the mode is performed. Thus, the mode switching means is configured. ing.

Incidentally, the feed back control is performed by the following procedure. That is, when the feedback control mode is entered, it is first judged whether or not there is a change in the arm detection value B, and if YES is judged, it is then judged whether or not the counter is operating and the counter is judged. If YES is determined as being in operation, time is measured from the counter data, and it is determined whether the changing speed of the lift arm 5 is appropriate. If YES is judged as appropriate, the ON-OFF duty ratio is maintained as it is. On the other hand, if NO is determined as inappropriate, it is determined whether the changing speed of the lift arm 5 is too fast. If YES is determined as too fast, the duty ratio of the ON time is changed. If the control is made to be smaller, and conversely NO is judged as being too slow, the duty ratio of the ON time is controlled to be large, and thereby the operating speed of the lift arm 5 is kept constant. To do.

In the embodiment of the present invention constructed as described above, when the position control lever 7 is operated to the lower limit position and the working unit 2 is lowered from the upper limit position to the automatic plowing depth automatic setting depth with the automatic plowing depth set. Further, according to the above-described control means, the working unit 2 enters the deceleration control mode at the stage when the working unit 2 has lowered to the deceleration start value L that is the dashing prevention control start position, and the descending speed is gradually reduced. When the speed is reduced to a speed corresponding to the feed back control speed (duty ratio state of ON time t _s ), the dashing prevention speed mode is switched to the feed back control mode and the descent speed is lowered at a constant low speed.

As described above, in the case where the present invention is implemented, when the anti-dashing control is performed, the speed mode is first changed to the deceleration control mode and then switched to the feed back control mode. A shock at the time of shifting to the prevention control state is largely avoided, and a smooth dashing prevention control without a shock can be performed. After the dashing prevention speed is reduced to a predetermined state, it becomes a constant speed based on the feed back control mode, so even if the working part weight changes or the oil temperature rises, it does not depend on these changes. In addition, the anti-dusting speed at a constant speed can always be obtained, so that the anti-dusting control can be stably performed and the workability can be remarkably improved.

Moreover, this is of course convenient in that the start position of the dashing prevention control can be arbitrarily adjusted if necessary, but further, the dashing prevention speed can be adjusted freely by using the dashing prevention speed adjusting unit 17. Therefore, it is possible to perform the dashing prevention control suitable for the working condition. In this case, the deceleration control mode is switched to the feed back control mode by decelerating to a speed corresponding to the feed back control speed, that is, by adjusting the dashing prevention speed adjuster 17, the duty ratio of the ON time is, for example, t. _By determining that the deceleration control mode has ended when t ₆ or t ₄ instead of _s , it is possible to avoid the occurrence of shock when switching to the feed back control mode when adjusting the dashing prevention speed. Therefore, even if the dashing prevention speed changes, smoothness is not impaired.

Needless to say, the present invention is not limited to the above-described embodiment, and for example, mode switching from the deceleration control mode to the feed back control mode is performed by detecting the duty ratio of the ON time as in the above-described embodiments. Instead of this, it can be performed by detecting the arm angle of the lift arm or by detecting the time from the start of the dashing prevention control. Further, it can be detected by using the tilling depth detection sensor 15 provided on the working unit 2 side. in this case,
Dusting prevention control by deceleration control mode
Has started before the ground contact, and when the flat plate 2a comes into contact with the ground while descending while decelerating to cause an angle change, the detection value D of the working depth detection sensor 15 changes in association with this. However, it is judged whether this change has occurred,
It may be possible to determine that the deceleration control mode has ended when the determination is YES due to a change and to switch from the deceleration control mode to the feed back control mode.
By doing so, when the working machine 2 descends, it always descends in the constant feed back control mode after the ground contact, so that, for example, when the tire subsidence amount is different. In this case, the dashing prevention control can be performed with a certain relationship, and it is convenient because the tidying work can be performed in an orderly manner with the headland.

[Advantages] In summary, since the present invention is configured as described above, when the working part is lowered from the upper limit position to the working height, the dashing prevention speed is set during the lowering so that safe work can be started. However, due to the mode switching means provided in the dashing prevention control mechanism, this dashing prevention speed is in a speed control state in which the deceleration control mode is gradually decelerated at the beginning and is switched to the feed back control mode. The transition to the dashing prevention control is smooth, and the occurrence of shock is reliably avoided. Moreover, after switching to the feed back control mode, the dashing prevention control will always be performed at a constant speed even if the temporary work unit weight changes or the oil temperature changes, and stable work performance is demonstrated. It is possible.

In addition to adjusting the start position of the dashing prevention control, when the mode is switched from the deceleration mode of the dashing prevention control to the feed back control, the descending speed by the feed back control is also adjusted arbitrarily according to the dashing prevention speed. Therefore, it is possible to switch from the deceleration control mode to the feed back control mode without causing shock even if the dashing prevention control start position is adjusted, and even if the dashing prevention speed changes. There is no loss of smoothness.

Moreover, the starting position of the dashing prevention control is convenient in that it can be adjusted arbitrarily according to the field conditions, etc., but since the descending speed in the feed back control mode can also be adjusted, the dashing prevention control can be adjusted. The feedback control speed can be adjusted in accordance with the adjustment of the start position, which can avoid the occurrence of shock when switching from the anti-dashing control to the feedback control mode, and the anti-dashing speed changes accordingly. However, there is no loss of smoothness.

[Brief description of drawings]

FIG. 1 shows an embodiment of a dashing prevention control structure for a work vehicle according to the present invention. FIG. 1 is an overall side view of an agricultural tractor, FIG. 2 is a front view of an adjusting section, and FIG. FIG. 4 is a block circuit diagram of the control mechanism, FIG. 4 is a flow chart of the control procedure, FIG. 5 is a timing chart of the control procedure, FIG. 6 is a timing chart of the anti-dusting speed mode, and FIG. 7 is a second chart. FIG. 8 is a timing chart of a control procedure of the embodiment, FIG. 8 is a timing chart of the same control procedure, and FIG. 9 is a timing chart of the same anti-dashing speed mode. In the figure, 1 is a traveling machine body, 2 is a working unit, 7 is a position control lever, and 10 is a control unit.

Claims (3)

[Scope of utility model registration request] 1. A dashing prevention control mechanism for reducing the descending speed of the working unit set to the upper limit position to the working height before the working unit reaches the working height. In the work vehicle that becomes
The dashing prevention control mechanism sets the dashing prevention speed mode to a deceleration control mode in which the descent speed gradually decreases at the beginning of the dashing prevention control, and then to a feed back control mode in which the descent speed becomes constant, and a dashing prevention control. The starting position adjusting means for adjusting the starting position of the vehicle and the descending speed adjusting means for adjusting the descending speed in the feed back control mode are provided. 2. The mode switching means includes a mode switching from a deceleration control mode to a feed back control mode.
2. A structure for utility model registration according to claim 1, further comprising switching detection means for detecting when deceleration in a deceleration control mode has reached a predetermined state and switching the switching mode. . 3. The mode switching means is connected to a working depth detecting sensor on the side of the working unit, and switches the mode from the deceleration control mode to the feed back control mode based on the ground contact detection of the detecting sensor. A control structure for preventing dusting of a working vehicle according to claim 1, wherein the utility model registration is defined as: