JP2000032806A - Cultivator elevation controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cultivator capable of starting cultivating operations while preventing a rise in the land and free running time even in the case that the cultivator starts traveling at any speed, high or low, while enabling the rotary cultivator to be controlled so as to be difficult to cause a steep change in a driving load when making the cultivator descend to the cultivating operation level as quickly as possible. SOLUTION: When starting cultivating operations while making a cultivator descend after the cultivator took a turn, the apparatus of the invention conducts the descending of the rotary cultivator at high speed from a higher nonoperational level to a preset cultivating level L2 above the ground while actuating a solenoid-proportionally controlled valve with electric currents I0 and I and at low speed from the level L2 to the cultivating operation level while actuating the above valve with electric currents I1 and I2. The speed of the rotary cultivator descending from the level L2 to the cultivating operation level is changed according to the cultivator speed detected before the cultivator starts taking a turn, in such a way that the higher the cultivator speed is, the higher the descending speed adjusted becomes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lifting and lowering control device for a tilling machine having a hydraulic actuator for driving a rotary tilling device up and down with respect to a self-propelled body.

[0002]

2. Description of the Related Art Conventionally, an electric proportional control valve for controlling a hydraulic actuator, current control means for supplying a set current to the electric proportional control valve, and the like are conventionally used in the above-described cultivator, as disclosed in Japanese Patent Publication No. 2559890. When lowering the tilling device that has been raised to the non-working level to the tilling work level, the flow of the control valve becomes large and the tilling device quickly descends until the tilling claw of the tilling device begins to touch the ground, In some cases, the flow rate of the control valve becomes small and the tilling device descends slowly. That is, after the tilling device is lifted and turned on a headland or the like, when the tilling device is lowered and the tilling operation is started, the tilling claw is gradually lowered in the soil while the tilling device is lowered as quickly as possible. Rush,
It is possible to start while avoiding a sudden increase in the engine load and a significant rise of the tillage soil in the rear.

[0003]

Conventionally, the airframe has been increased in horsepower so that work traveling can be started at an extremely low speed or at a high speed. After the aircraft started touching down, it descended slowly at a constant speed regardless of the running speed of the aircraft. For this reason, when the work traveling is started at a low speed, the tilling claws rush into the soil earlier than the machine traveling speed, and the swelling of the cultivated soil formed behind the tilling apparatus may increase, and the work traveling may be stopped. When starting at a high speed, the plowing of the tilling claws into the soil is slow compared to the running speed of the machine, and there may be many parts that can be formed behind or below the tilling apparatus in the untilled or insufficiently tilled state. SUMMARY OF THE INVENTION An object of the present invention is to provide a lift control device for a cultivator capable of working while avoiding the occurrence of the above-described troubles related to engine load and plowing even when the body starts running at any speed, high or low.

[0004]

The constitution, operation and effect of the invention according to claim 1 are as follows.

[0005] In a lifting and lowering control device for a tiller having a hydraulic actuator for driving a rotary tillage device up and down with respect to a self-propelled body, an electromagnetic proportional control valve for controlling the hydraulic actuator, and a self-propelled body of the rotary tillage device Height detecting means for detecting the height with respect to, speed storage means for storing the traveling speed of the self-propelled body in the previous tilling work process, and the electromagnetic proportional control valve based on information from the height detecting means High-speed elevating control means for automatically operating and lowering the rotary tillage device automatically from a non-working level to a deceleration setting level on the ground; and the electromagnetic proportional control valve based on information from the height detecting means. Is automatically operated to a smaller oil amount than the high-speed elevating control means, and the oil amount of the electromagnetic proportional control valve is increased as the traveling speed stored by the speed storage means is faster. And are a low-speed lift control means for lowering the rotary plow automatically from the speed reduction setting level to set the tilling levels.

[Operation] When the tilling device is raised to a non-working level and then lowered, such as when the work is resumed after turning on the headland, first, the high-speed vertical control means operates the electromagnetic proportional control valve. The tilling device is lowered at a high speed, and the tilling device is lowered to the set level for deceleration. Thereafter, the low-speed raising and lowering control means operates the electromagnetic proportional control valve to a smaller flow rate than the high-speed raising and lowering control device, and the tilling is performed. The nail is lowered into the tilling work level so that the nail enters the soil at a slow speed. At this time, when starting the work by running the aircraft at high speed, since the tillage work of the previous process is often also performed at high speed, the speed storage means stores the high speed running speed, Based on this high-speed stored traveling speed, the low-speed elevation control means operates the electromagnetic proportional control valve to a relatively large flow rate, and the tilling claws enter the soil relatively quickly. Then, when the work is started by running the aircraft at a low speed, since the tilling work of the previous process is also often performed at the low speed, the speed storage means stores the low speed of the running,
Based on this low-speed stored traveling speed, the low-speed elevation control means operates the electromagnetic proportional control valve at a relatively small flow rate, and the tilling claw enters the soil very slowly.

[Effect] When the tilling device is returned to the tilling operation level and the work is performed, such as after the tilling device is raised to the non-working level and the headland is turned, initially, the tilling device descends at a high speed,
After reaching the deceleration setting level, it descends at a low speed and slowly enters the soil to reach the tilling work level, and as a whole, the tilling work level does not easily cause a rapid and sudden change in drive load To reach. And when the tilling device descends from the deceleration setting level to the tilling work level, in a case where the aircraft is traveling at a high speed, a distance traveled by the aircraft before the tilling device starts the tilling operation, so-called idle running. When descending quickly so as to reduce the distance and running at low speed, work the tilling device by descending slowly so that the tilling device does not reach the field scene too fast. It is possible to work while keeping the level as quickly as possible, while preventing the engine load from suddenly increasing and causing engine stall. In addition, it is possible to perform a good work regardless of the running speed, such as a low running speed with little swelling of the soil, and a high speed running with little untilled or insufficiently tilled portions.

The structure, operation and effect of the invention according to claim 2 are as follows.

[Structure] In the structure according to the first aspect of the present invention, the speed storage means is configured to store an average traveling speed of the self-propelled body in a previous tilling work process.

[Effect] Even if the vehicle travels while changing the speed during the previous work traveling, the average traveling speed is stored in the speed storage means, and when the tilling device is lowered from the deceleration setting level to the tilling operation level, the average traveling speed is reduced. Is regarded as the current traveling speed, and the descending speed of the tilling apparatus is controlled by setting the descending speed based on the average traveling speed. That is, even if the gear is shifted during work traveling, since the speed at which the tiller is lowered to the tilling work level is set based on the average traveling speed, the speed is set based on the specific traveling speed that appears during work traveling. As compared with such a configuration, the tillage device can be lowered to the working level at a speed adapted to the next working speed.

[Effect] Even if the traveling speed is changed during the work, the tilling device is lowered to the work level at the speed set based on the average traveling speed, and the occurrence of the above-mentioned troubles related to the rise of the plowed soil and the plowing is minimized. Work traveling can be started while restraining.

The structure, operation and effect of the invention according to claim 3 are as follows.

[0013] [Structure] In the structure of the invention according to claim 1 or 2, the low-speed elevation control means comprises a first low-speed elevation control means and a second low-speed elevation control means, and the first low-speed elevation control means is a rotary tilling device. Is lowered from the deceleration setting level to the second deceleration setting level, and the second low-speed elevating / lowering control means operates the electromagnetic proportional control valve to a smaller oil amount than the first low-speed elevating / lowering control means. The apparatus is configured to be lowered from the second deceleration set level to the set tillage work level.

[Operation] When lowering the tilling device from the rising non-working level to the cultivating work level, the tilling work level is reduced when the deceleration set level is reached, and then decelerated again when the second deceleration set level is reached. To reach
The lowering control can be performed by increasing the speed difference between the speed at which the speed reaches the set level for deceleration and the speed at which the speed reaches the tilling work level while suppressing the deceleration shock and the stop shock to a small extent.

[Effect] The tillage device, which can suppress the occurrence of troubles related to the swelling of the cultivated soil and plowing, can be obtained in a state in which the tillage device can be operated smoothly by decelerating and descending with little deceleration shock and stop shock.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a pair of left and right driving and steerable front wheels 1, 1 and a pair of left and right driving rear wheels 2, 2 are self-propelled, and an engine 3 is driven. A transmission case 5 forming a rear part of a self-propelled body including a driving unit provided and a driving unit provided with a driver seat 4.
The rotary tilling device 7 is connected to the rear end of the rotary tilling device 7 via a two-point link mechanism 6, and the rotation output of the engine 3 is transmitted from the transmission case 5 to the rotary tilling device 7. A lift cylinder 9 in which a piston rod is interlocked with a rotation support shaft of a pair of left and right lift arms 8 supported by the transmission case 5 so as to be vertically swingable is provided inside the transmission case 5.
Is performed, the lift cylinder 9 swings the two lift arms 8 up and down, and the lift rod 10 connecting the one lift arm 8 and the one link mechanism 6 and the other lift arm 8 By operating the link mechanism 6 up and down with respect to the transmission case 5 via a rolling cylinder 11 connecting the other link mechanism 6, a lift cylinder 9 as an example of a hydraulic actuator is provided.
Thus, the rotary tilling device 7 can be driven up and down with respect to the self-propelled body, thereby constituting a riding cultivator.

The hydraulic circuit of the lift cylinder 9 is shown in FIG.
It is configured as shown in FIG. That is, the lift cylinder 9
Is connected to an excess flow port of the flow priority valve 14 via an oil passage 13. The flow priority valve 14 preferentially supplies a fixed amount of the pressure oil supplied by the hydraulic pump 15 from the control flow port to the rolling valve 16 and supplies the remaining amount of the pressure oil from the surplus flow port to the control valve 12. It is a flow control valve to supply. Rolling valve 16
Is for controlling the rolling cylinder 11, and the rolling cylinder 11 is operated by rolling the tilling device 7 with respect to the vehicle body by changing the distance between the lift arm 8 and the link mechanism 6 to which the rolling cylinder 11 is connected. Is what you do. That is, the hydraulic pump 15 is
The remaining pressure oil excluding a certain amount of pressure oil preferentially supplied to the rolling control of the tillage device 7 out of the pressure oil driven and supplied by the lift cylinder 9 through the control valve 12.
To supply.

The control valve 12 includes a lift control valve 12a for operating the lift cylinder 9 on the raising side of the tilling device 7, a first solenoid valve 12b for switching and controlling the lift control valve 12a by pilot oil pressure, and a lift cylinder 9 , A lowering control valve 12c for operating the lowering side of the tillage device 7 and a second electromagnetic valve 12d for switching and controlling the lowering control valve 12c by pilot hydraulic pressure.
The flow rate when controlling the lift cylinder 9 to the ascending side of the tilling device 7 is also controlled so that it can be controlled by giving an electric signal to the solenoid valve 12b and the second solenoid valve 12d. Can also be controlled. That is, when a current is supplied to the solenoid SL1 of the first solenoid valve 12b and the current value of the current is adjusted, the first solenoid valve 12b changes the pilot pressure according to the current value. Thereby, the opening degree of the lift control valve 12a changes in proportion to the pilot pressure, controls the flow rate of the pressure oil supplied from the hydraulic pump 15 to the lift cylinder 9, and moves the lift cylinder 9 to the rising side of the tillage device 7. Activate and adjust its activation speed. The solenoid SL2 of the second solenoid valve 12d
And the current value of the current is adjusted, the second solenoid valve 12d changes the pilot pressure according to the current value. As a result, the opening degree of the descending control valve 12c changes in proportion to the pilot pressure, controls the flow rate of the hydraulic oil flowing out of the lift cylinder 9, and moves the lift cylinder 9 to the descending side of the tilling device 7 and the operation thereof. Adjust the speed.

As shown in FIG. 1, a working depth setting dial 19 provided on a control box 18 supported by a rear wheel fender 17 of a self-propelled body, and a position lever provided on a side of a driving seat 4 of a driving unit so as to be swingable. 20a, an elevation control device that includes an elevation lever 21 slidably provided on the side of the steering handle H of the driving unit, and controls the elevation of the rotary tillage device 7 by operating the lift cylinder 9. It is configured as shown in FIG. That is, the tillage depth setting device 22 operated by the tillage depth setting dial 19, the position setting device 23 operated by the position lever 21, and the ground surface as ground height detection means for detecting the ground height of the rotary tillage device 7. Height sensor 2
4. Anti-aircraft height sensor 2 as anti-aircraft height detecting means for detecting the height of rotary tilling device 7 relative to the self-propelled airframe.
5. The vehicle speed sensor 26 for detecting the vehicle speed of the self-propelled body
In addition to being linked to a control device 28 via a D converter 27, an up switch 21 a and a down switch 21 b operated by the up / down lever 21 are linked to the control device 28. The control device 28 is linked to power transistors 30a, 30b linked to the solenoids SL1, SL2 of the control valve 12. Tillage depth setting device 22
The tilling depth setting dial 19 comprises a potentiometer for detecting the operating position of the cultivating depth setting dial 19, and the cultivating depth corresponding to the operating position of the cultivating depth setting dial 19 is set as a control target cultivating depth to be maintained by the cultivating device 7, and the set control target cultivating depth is set. Is output as an electric signal. The position setting device 23 is a position lever 2
The height of the body corresponding to the operation position of the position lever 20 is set as the height of the control target with respect to which the cultivator 7 is to be moved up and down, and the set control target with respect to the body height is set. Is output as an electric signal. The ground height sensor 24 is provided for the tilling claw 7 of the tilling device 7.
a of a potentiometer in which an operation unit is linked via a link mechanism to a rear cover 7b covering the rear of the rear cover 7b.
The height of the tillage device 7 with respect to the ground is detected based on the swing angle of b with respect to the fixed cover, and the detection result is output as an electric signal. That is, the upper end side of the rear cover 7b is supported by the fixed cover so as to be rotatable around the horizontal axis of the machine body, and the lower end side of the rear cover 7b is grounded behind the tilling device 7,
When the tillage device 7 moves up and down with respect to the field scene, the rear gabber 7b
Swings up and down relative to the fixed cover to activate the potentiometer. The anti-machine body height sensor 25 is a potentiometer in which an operation unit is linked to the lift arm 8, and detects a height of the tilling device 7 with respect to the self-propelled body based on a swing angle of the lift arm 8 with respect to the transmission case 5.
The detection result is output as an electric signal. Vehicle speed sensor 26
Consists of a rotation sensor that detects the rotation speed of a rotating shaft that transmits the rotation output of the traveling transmission to the rear wheel differential mechanism, and detects the traveling speed of the self-propelled body based on the driving rotation speed of the rear wheel 2. , And outputs the detection result as an electric signal.

The signals from the tillage setting device 22 and the sensors 23 to 26 are input to a control device 28 via an A / D converter 27, and the signals from the up switch 21a and the down switch 21b are directly sent to the control device 28. Is input to Control device 2
8 outputs an intermittent pulse signal to the power transistors 30a and 30b to output the power transistors 30a and 30b.
By driving the solenoid S of the control valve 11
By supplying the intermittent pulse current to L1 and SL2 to operate the control valve 11, and by adjusting the duty cycle of the intermittent pulse signal supplied to the power transistors 30a and 30b, the current supplied to the solenoids SL1 and SL2 is controlled. The opening of the control valve 12 is adjusted by adjusting the current value. The resistor R interposed in the path 31 from the solenoids SL1 and SL2 converts the current value of the current supplied to the solenoids SL1 and SL2 into a voltage value, and converts the converted voltage value into a feedback path 32, A / The data is fed back to the control device 28 via the D converter 27.

The control device 28 is constituted by a microcomputer and is provided with an automatic plowing depth control means 28a, a position control means 28b, and a forced ascending control means 28c. By operating the position lever 20 and the elevating lever 21, The tilling device 7 can be operated while being automatically controlled to move up and down, and the tilling device 7 can be moved up and down.

That is, in performing the tilling work, the body is driven by operating the position lever 20 to the work position set at the stroke end of the operation range. Then
The control device 28 enters the mode of the automatic plowing depth control based on the information from the position setting device 23, and the height detected by the ground height sensor 24 becomes a height corresponding to the setting plowing depth set by the plowing depth setting device 22. In order to control the lift cylinder 9,
The control valve 12 is automatically operated based on information from the ground height sensor 24 and information from the tillage depth setting device 22.
Thereby, even if the self-propelled body leans back and forth, the work can be performed while automatically raising and lowering the tillage device 7 so that the tillage depth becomes the tillage depth set by the tillage depth setting device 22.

When the tillage device 7 is artificially moved up and down, the position lever 20 is moved up or down in an operation area deviating from the working position, or the up / down lever 21 is moved up or down. I do. When the position lever 20 is operated, the control device 28 enters the position control mode based on the information from the position setting device 23, and only the stroke corresponding to the operation stroke of the position lever 20 in the direction corresponding to the operation direction of the position lever 20. The control valve 12 is operated based on the information from the position setting device 23 and the information from the anti-aircraft height sensor 25 so that the lift cylinder 9 operates. Thereby, the tillage device 7 moves upward or downward corresponding to the operation direction of the position lever 20 by a stroke proportional to the operation stroke of the position lever 20. When the raising / lowering lever 21 is operated to the raising side, the raising switch 21a is turned on, the control device 28 enters the forced lifting control mode based on information from the raising switch 21a, and the lift cylinder 9 is set to the predetermined lifting position. The control valve 12 is operated so as to be in the side state. At this time, the control device 28 obtains a feedback signal from the anti-machine height sensor 25 that the tillage device 7 has reached the predetermined rising non-working level. As a result, the tillage device 7 rises to a predetermined rising non-working level that has surfaced from the field scene. When the raising / lowering lever 21 is operated on the ascending side and then operated on the descending side, the descending switch 21b is turned on, and the control device 28 returns to the automatic plowing depth control mode based on the information from the descending switch 21b, and The lift cylinder 9 is controlled so that the height detected by the sensor 24 becomes a height corresponding to the set till depth set by the till depth setting device 22. Thereby, the tilling device 7 is lowered to the tilling operation level set by the tilling depth setting device 22.

The control device 28 is further provided in FIGS.
The tillage device 7 is operated to descend as shown in FIG. 6 when the body turns on a headland or the like. That is, as shown in steps # 1 to # 4, prior to the raising of the tilling device 7, in the previous tilling operation process, the vehicle speed detected by the vehicle speed sensor 26 is read, and the tilling depth set by the tilling depth setting device 22 and the ground height are set. The average vehicle speed V is calculated based on the detected vehicle speed within the set time while the automatic cultivation depth control is stable by balancing the cultivation depth detected by the sensor 24.
Is calculated, and the average vehicle speed V is stored in the speed storage means 28d which is a memory of the control device 28. In addition, # 5,6
As shown in the step, the airframe level at which the tilling claw 7a of the tilling device 7 starts to contact the ground is calculated from the actual measured values of the ground height sensor 24 and the airframe height sensor 25 and the characteristics of the link mechanism 6, and Set level to deceleration level L
Set as 2. Then, as shown in steps # 7 and # 8, when the forcible raising operation by the raising switch 21a or the raising operation by the position lever 20 is performed,
The tilling device 7 is driven to rise. After the aircraft turns, # 9, #
As shown in step 10, when the descending operation is performed, the set plowing depth set by the tillage depth setting device 22 is read, and the plowing device 7 is controlled to descend so as to reach the set plowing depth as follows. That is, as shown in steps # 11 and # 12, the height detected by the anti-aircraft height sensor 25 is equal to the deceleration setting level L2.
Until the shift setting level L1, which is set at a higher level, the drive current I0 having the maximum duty ratio is supplied to the control valve 12 to lower the tilling device 7 at a high speed. #
As shown in steps 13 to # 15, until the speed decreases from the shift setting level L1 to the deceleration setting level L2,
The deviation Δθ between the height detected by the anti-aircraft height sensor 25 at that time and the deceleration setting level L2 is calculated, and this deviation Δθ
The supply current I is determined by the characteristics obtained from the map data based on the characteristics of the lift cylinder 9 and the control valve 12 corresponding to
Is determined, and the tillage device 7 is lowered while gradually decelerating. As shown in # 16, when the vehicle speed falls to the deceleration setting level L2, the average vehicle speed V is set based on the map data in which the relationship between the average vehicle speed V and the control valve drive current I1 is set.
Is obtained for the control valve drive current I1. That is, the control valve drive current I1 is determined in a state where the control valve drive current I1 increases as the average vehicle speed V increases. And # 17,
As shown in step # 18, the control valve driving current I1
Is supplied to the control valve 12, and the tillage device 7 is slowly lowered at a speed lower than the speed at which the tillage device 7 is lowered to the set level L2 for shifting. As shown in steps # 18 and # 19, the level at which the rear cover 7b starts to touch the ground is set as a second deceleration setting level L3 located lower than the deceleration setting level L2, and the tilling device 7 is turned on. When the second deceleration setting level L3 is reached, the control valve drive current I2 corresponding to the average vehicle speed V is obtained based on the map data in which the relationship between the average vehicle speed V and the control valve drive current I2 is set. That is, as the average vehicle speed V increases, the control valve driving current I2 increases.
Is large, the control valve drive current I2 is determined. Then, as shown in steps # 20 to # 22, the control valve drive current I2 is supplied to the control valve 12, and the speed at which the tilling device 7 is lowered from the deceleration setting level L2 to the second deceleration setting level L3. Lower slowly at a lower speed. Thereafter, as shown in step # 23, automatic tillage depth control is executed so that the height detected by the ground height sensor 24 is maintained at the set tillage depth set by the tillage depth setting unit 22. Then, the average vehicle speed V during the current work traveling is stored in place of the previously stored average vehicle speed V for the tilling apparatus lowering control at the time of the next body turning. Further, when the work has not been performed yet and the stored average vehicle speed V based on the actual vehicle speed does not exist, for example, immediately after the engine 3 is started, the provisional average vehicle speed preset for the initial setting is adopted. And the descending control is executed.

That is, # 11 to # 15 constitute the high speed up / down control means 28e.
Operates the electromagnetic proportional control valve 12 with the currents I0 and I based on the information from the anti-aircraft height sensor 25, and lowers the tilling device 7 from the rising non-working level to the deceleration setting level L2 on the ground at a high speed. . Steps # 15 to # 22 constitute the low-speed elevation control means 28f. The low-speed elevation control means 28f operates the electromagnetic proportional control valve 12 with the currents I1 and I2 based on information from the anti-aircraft height sensor 25. Then, the flow rate of the control valve 12 is made smaller than that of the high-speed raising and lowering control means 28e, and the tilling apparatus 7 is lowered at a low speed from the deceleration setting level L2 to the tilling depth setting level by the tilling depth setting device 22. Further, the lowering control is performed by increasing the flow rate of the control valve 12 so that the higher the average vehicle speed V of the self-propelled body in the previous tilling operation process, the faster the tilling device 7 descends. Steps # 15 to # 18 constitute the first low-speed elevating control unit 28g of the low-speed elevating control unit 28f. The electromagnetic proportional control valve 12 is operated by the current I1, and the tilling device 7 is set for deceleration. It is lowered at a low speed from the level L2 to the second deceleration setting level L3. # 18 to # 2
The two steps are the second of the low speed elevation control means 28f.
The low-speed raising and lowering control means 28h is configured to operate the electromagnetic proportional control valve 12 by the current I2 to lower the tilling device 7 from the second deceleration setting level L2 to the tilling work level at a low speed.

Thus, when the work is resumed after turning on the headland, when the tilling device 7 is raised to the non-working level and then lowered, the high-speed lifting and lowering control means 28e first activates the control valve 12. When the tillage device 7 is operated at the currents I0 and I and descends at a high speed from the ascending non-working level to the deceleration set level L2, first, the first low-speed elevating control unit 28g operates the control valve 12 with the driving current I1. When the tilling device 7 descends slowly at a lower speed than the descending speed until reaching the deceleration setting level L2, and then descends to the second deceleration setting level L3, the second low-speed elevating control means 2
8h operates the control valve 12 with the drive current I2 and
Gradually lowers to the tilling work level at a lower speed than the lowering speed until reaching the deceleration setting level L3,
The tilling device 7 descends quickly to the ground, and the tilling claws 7a gently rush into the soil so that a sudden change in the engine load is unlikely to occur. When the work is resumed while the body is running at a high speed, the tilling device 7 descends relatively quickly in the soil so that the idle running distance is reduced, and the work is restarted while the body is running at a low speed. In this case, the tillage device 7 descends at relatively low speed in the soil so as to suppress the rise of the plowed soil.

[Alternative Embodiment] Instead of a rotation sensor, a vehicle speed sensor may be replaced with a potentiometer for detecting whether the traveling auxiliary transmission is switched to a high speed side or a low speed side, or a detection switch. May be implemented.

[Brief description of the drawings]

FIG. 1 is a side view of the entire riding cultivator.

FIG. 2 is a hydraulic circuit diagram of a lift cylinder.

FIG. 3 is a block diagram of a tillage device elevating control.

FIG. 4 is a flowchart of a tillage device descending control.

FIG. 5 is a flowchart of a tillage device descending control.

FIG. 6 is an explanatory view of a tillage device descending speed.

[Explanation of symbols]

 Reference Signs List 7 rotary tillage device 9 hydraulic actuator 12 electromagnetic proportional control valve 25 height detecting means 28d speed storage means 28e high speed up / down control means 28f low speed up / down control means 28g first low speed up / down control means 28h second low speed up / down control means L2 deceleration setting level L3 2nd deceleration setting level

Claims (3)

[Claims] 1. A lift control device for a tiller having a hydraulic actuator for driving a rotary tiller up and down relative to a self-propelled body, comprising: an electromagnetic proportional control valve for controlling the hydraulic actuator;
Height detection means for detecting the height of the rotary tilling device with respect to the self-propelled body, speed storage means for storing the traveling speed of the self-propelled body in the previous tilling work process, and information based on the height detection means. High-speed lifting and lowering control means for automatically operating the electromagnetic proportional control valve to automatically lower the rotary tillage device from a rising non-working level to a deceleration setting level on the ground, and information from the height detecting means. The electromagnetic proportional control valve is automatically operated to a smaller amount of oil than the high-speed elevating / lowering control means, and the oil amount of the electromagnetic proportional control valve increases as the stored traveling speed by the speed storage means increases. A low-speed elevating control means for automatically lowering the rotary tillage device from the deceleration set level to the set tillage work level. 2. The tilling machine lift control device according to claim 1, wherein said speed storage means is configured to store an average traveling speed of the self-propelled body in a previous tilling operation process. 3. The low-speed up / down control means includes a first low-speed up / down control means and a second low-speed up / down control means, and the first low-speed up / down control means sets the rotary tilling device from the deceleration setting level to a second deceleration setting. The rotary tilling apparatus is lowered from the second deceleration setting level while the second low-speed elevating control means operates the electromagnetic proportional control valve to a smaller oil amount than the first low-speed elevating control means. 3. The lifting and lowering control device for a cultivator according to claim 1, wherein the lowering operation is performed to a tilling operation level.