JP2002281804A - Posture controller for working car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controlling structure for lifting and lowering of a rice transplanter capable of controlling a control current of an electromagnetic type flow control valve for controlling the lifting and lowering operation so that the lifting and lowering operation of a seedling planting device can smoothly be carried out. SOLUTION: This posture controller for a working car is composed so that the seedling planting device can be lifted and lowered by charging a pressure oil from a hydraulic pump 30 driven with an engine 6 is charged through an electromagnetic type flow control valve 41 to a hydraulic cylinder 3 for lifting and lowering. When the seedling planting device is set at a prescribed plowing depth, the electromagnetic type flow control valve 41 is composed so as to regulate the value of the control current of the electromagnetic type flow control valve 41 with a duty ratio so that the quantity of the pressure oil sufficient to the make up for a deviation of the height of the seedling planting device from the prescribed height should be charged into the hydraulic cylinder 3. The controller is composed so as to make a correction so that the duty ratio is increased when the speed of the engine 6 is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump which is driven by an engine and a hydraulic oil supplied from the pump to the hydraulic actuator, in which a working device is connected to a traveling machine body via a hydraulic actuator so as to be able to change its posture. An electromagnetic flow control valve for controlling the electromagnetic flow control valve, the control current of the electromagnetic flow control valve is set by the duty ratio, and the valve opening is adjusted to automatically set the supply hydraulic oil amount of the electromagnetic flow control valve. The present invention relates to a work vehicle attitude control device provided with control means.

[0002]

2. Description of the Related Art Conventionally, in order to set a duty ratio for an electromagnetic flow control valve, proportional control is performed based on a deviation between a detection value of a detection sensor for detecting a posture of a working device and a set value set by a setting device. Was set to be performed.

[0003]

In the electromagnetic flow control valve, the control current is controlled by the duty ratio to change the valve opening and control the flow rate supplied to the hydraulic actuator. Is not taken into account. However, since the pump is driven by the engine, if the engine speed fluctuates,
The discharge amount of the pump also fluctuates, and the amount of oil supplied to the hydraulic actuator fluctuates.

An object of the present invention is to provide a work vehicle attitude control device capable of smoothly changing the attitude of a work device capable of stably supplying an amount of oil supplied to a hydraulic actuator even when the engine speed fluctuates. Is to do.

[0005]

[Means for Solving the Problems] In the invention according to claim 1 of the present invention, when the number of revolutions of the engine falls below a predetermined number of revolutions, the duty ratio is increased to suppress a decrease in the supplied hydraulic oil amount. There is provided a correction means for performing correction as described above, and the operation and effect thereof are as follows. [Effects] In other words, when the engine speed decreases, the amount of oil injected into the electromagnetic flow control valve decreases. Therefore, by increasing the duty ratio for the electromagnetic flow control valve, the supply amount due to the decrease in the rotational speed is reduced. Can be compensated for.

In the invention according to claim 2 of the present invention, when the rotation speed of the engine is lower than a predetermined rotation speed, if the duty ratio is large, the duty ratio is further increased to reduce the supplied hydraulic oil amount. There is a correction means for correcting so as to suppress the reduction, and the operation and effect are as follows. [Operation and effect] When the engine speed decreases, the decrease in the supply hydraulic oil flow sent out from the electromagnetic flow control valve is as follows.
When the supply hydraulic oil flow rate is large, that is, as shown in FIG. 3B, it appears in a region where the duty ratio is large. Therefore, when the engine speed decreases, a correction is made for a motor with a large duty ratio in order to compensate the amount of oil supplied to the hydraulic actuator.

In the invention according to claim 3 of the present invention, the flow rate characteristics between the engine speed and the pump discharge rate are compared with the pump discharge rate obtained based on the measured value for the engine speed. When the hydraulic oil amount determined by the duty ratio is a small flow rate, the duty ratio is maintained, and the hydraulic oil amount determined by the duty ratio is larger than the determined pump discharge amount. When the flow rate is a flow rate, a correction means for correcting the duty ratio so as to decrease the duty ratio is provided. The operation and effect are as follows. [Operation and effect] The case where the hydraulic oil amount determined by the duty ratio is a small flow rate as compared with the pump discharge amount obtained based on the measured value for the engine speed, that is, the hydraulic oil amount should be supplied to the hydraulic actuator When the hydraulic oil amount is smaller than the pump discharge amount, the flow rate required for control by the electromagnetic flow control valve is supplied, and the duty ratio is maintained. Conversely, the case where the hydraulic oil amount determined by the duty ratio is a large flow rate as compared with the calculated pump discharge amount, that is, the hydraulic oil amount to be supplied to the hydraulic actuator is smaller than the pump discharge amount If the flow rate is set to be large, it means that the flow rate required for control by the electromagnetic flow control valve has not been supplied, so that the duty ratio is corrected to be small.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an entire side view of a rice transplanter. In this rice transplanter, a seedling planting device 2 is moved up and down by a hydraulic cylinder 3 at a rear portion of a riding type traveling body 1. It is configured to be connected to the traveling machine body 1 via a swinging link mechanism 4 so as to be able to move up and down, and to mount a fertilizer device 5.

The traveling body 1 receives power from an engine 6 mounted on a front portion thereof through a hydrostatic stepless transmission 7 and a gear type transmission 8 so as to straddle four rows of seedlings. Left and right front wheels 9 and rear wheels 10 arranged at predetermined intervals in the left and right direction, and left and right auxiliary wheels 10A arranged side by side so as to straddle two rows of seedlings inside the left and right rear wheels 10. It is configured to transmit the power as running power, so that a sufficient thrust can be obtained.

At the center of the traveling machine body 1, a steering wheel 11 linked to the left and right front wheels 9, a main shift lever 12 for shifting the hydrostatic continuously variable transmission 7, and a gear shift for the gear type transmission 8 are operated. The boarding operation unit 15 including the auxiliary transmission lever 13 and the driver's seat 14 is formed.

The link mechanism 4 includes free ends of the left and right top links 4A connected to the rear of the traveling body 1 so as to be able to swing up and down around a horizontal axis P1 and a rear end of the traveling body 1 around a horizontal axis P2. It is configured by connecting the free ends of the left and right lower links 4B, which are connected to be able to swing up and down, by a vertical link 4C. At the lower end of the vertical link 4C, the seedling planting device 2 is connected to the traveling machine 1 so as to be able to roll around the longitudinal axis.

As shown in FIG. 1, the seedling planting apparatus 2 includes a feed case 19 receiving planting power from the engine 6, a planting transmission case 20 to which power is distributed and supplied from the feedcase 19, and each planting transmission. A rotary type planting mechanism 21 pivotally supported on the left and right sides of the rear part of the case 20, and a seedling table 2 reciprocating with a constant stroke in the left-right direction with respect to each planting mechanism 21
2. It is configured such that planting can be performed by four leveling floats 23 that level the planting site by each planting mechanism 21 in advance.

Next, an elevation control structure which is one of the attitude controls of the seedling planting apparatus 2 will be described. As shown in FIGS. 1 and 2, the left and right leveling floats 23 have horizontal axes P of the leveling float 23 that fluctuate as the planting work travels.
A float sensor 39 composed of a rotary potentiometer or the like for detecting the vertical swing angle around the ground 7 as the ground pressure is linked thereto, and a sensor float for detecting a change in the ground pressure by the leveling float 23 and the float sensor 39 linked thereto. S is configured. Each sensor float S is
The detected value is output to a control device 40 such as a microprocessor mounted on the traveling body 1.

As shown in FIG. 2, the control device 40 operates an electromagnetic flow control valve 41 for switching the flow state of hydraulic oil to the hydraulic cylinder 3 based on the average value of the ground pressure from the left and right sensor floats S. By doing so, the automatic elevation control means 40A for controlling the elevation of the seedling planting apparatus 2 so that the average value falls within the dead zone width of the preset target value.
By operating the rolling motor 42 mounted on the vertical link 4C of the link mechanism 4 on the basis of the difference between the ground pressures from the left and right sensor floats S, the seedlings are adjusted so that the ground pressure difference falls within a predetermined range. A rolling control means 40B for controlling the rolling of the planting apparatus 2 is provided as a control program, and by these control operations, the seedlings can be stably placed at a desired planting depth irrespective of changes in the undulation of the muddy surface of the field. It can be planted. Also, the leveling float 23 which is not affected by the wheel mark is used as the sensor float S.
Therefore, the raising and lowering control and the rolling control of the seedling planting apparatus 2 based on those contact pressures can be performed with high accuracy, so that the planting of the seedlings at a desired planting depth can be performed more accurately. It can be done well. Here, the automatic lifting control means 40A and the rolling control means 4
OB is referred to as a posture change control unit of the working device.

As shown in FIGS. 1 and 2, the raising / lowering control of the seedling planting apparatus 2 by the automatic raising / lowering control means 40A and the rolling control of the seedling planting apparatus 2 by the rolling control means 40B are performed on the right side of the driver's seat 14. Can be executed when the planting clutch lever 43 disposed on the side is set to the "automatic" position. The setting of the target value when the raising and lowering control of the seedling planting apparatus 2 is performed by the automatic raising and lowering control means 40A is performed by manually operating the setting device 44 for cultivating depth which is a rotary potentiometer mounted on the traveling machine 1. It can be done with.

The planting clutch lever 43 is equipped with a lever sensor 43A consisting of a rotary potentiometer for detecting the operating position and outputting the detected value to the control device 40. Control means 40 for controlling the raising and lowering of the seedling planting apparatus 2 and the operation of the planting clutch 45 incorporated in the gear type transmission 8 based on the
C is provided as a control program.

When the planting clutch lever 43 is operated to the "up" position, the seedling planting device 2 is raised, and when the planting clutch lever 43 is operated to the "down" position, the seedling planting device 2 is lowered. The operation state of the electromagnetic flow control valve 41 is switched so that the raising and lowering of the seedling planting device 2 is stopped when the planting device 2 is operated to the “neutral” position, and the planting clutch lever 43 is planted “on”.
A clutch motor for intermittently operating the planting clutch 45 so that the seedling planting device 2 performs the planting operation when operated to the position, and the planting planting device 2 stops the planting operation when operated to the planting “off” position. 46 is configured to switch the operation state.

When the planting clutch lever 43 is set to the "automatic" position, the manual control means 40C controls the operation of the neutral return type forced lifting / lowering operation lever 47 provided at the lower right of the steering wheel 11. The operation states of the electromagnetic flow control valve 41 and the clutch motor 46 are switched based on detection signals from the first switch 48 and the second switch 49 to be detected.

The seedling planting apparatus 2 is located at an ascending position deviating from the planting height position where the average value of the contact pressure from the left and right sensor floats S falls within the dead band width of the target value set by the setting device 44. When the ON signal is output from the first switch 48 by the downward swinging operation of the operation lever 47 in the position, the electromagnetic flow control valve 41 is so arranged that the seedling planting device 2 is lowered to the planting height position. Switch the operating state of.

When an ON signal is output from the second switch 49 by the upward swinging operation of the operation lever 47 in a state where the seedling planting device 2 is located at the planting height position, the seedling planting device 2 is set in advance. The operation state of the electromagnetic flow control valve 41 is switched so as to rise to the set upper limit position, and the seedling planting device 2 is switched.
Operating lever 47 in a state where is located at the planting height position
When the ON signal is output from the first switch 48 by the downward swinging operation, the operating state of the clutch motor 46 is switched so that the seedling planting apparatus 2 performs the planting operation.
When the operation lever 47 is swung upward while the seedling planting apparatus 2 is performing the planting operation, the second switch 4 is turned on.
When the ON signal is output from 9, the operation state of the clutch motor 46 and the electromagnetic control valve 41 is switched so that the seedling planting device 2 stops the planting operation and rises to the upper limit position.

The control of the manual control means 40C based on the ON signal from the first switch 48 causes the seedling plant 2
As the vehicle reaches the planting height position, the raising and lowering control of the seedling planting apparatus 2 by the automatic raising and lowering control means 40A and the rolling control of the seedling planting apparatus 2 by the rolling control means 40B are executed. Control of the seedling planting apparatus 2 by the automatic raising / lowering control means 40A and the seedling planting apparatus 2 by the rolling control means 40B
The rolling control is stopped.

Next, the electromagnetic flow control valve 41 will be described. As shown in FIG. 5, the electromagnetic flow control valve 41 is a rising control valve 41 for supplying hydraulic oil to the hydraulic cylinder 3.
A, an electromagnetically operated rising pilot valve 41AP for opening and closing the rising control valve 41A with a pilot pressure, a lowering control valve 41B for discharging hydraulic oil from the hydraulic cylinder 7,
An electromagnetically operated lowering pilot valve 41BP that opens and closes the lowering control valve 41B with a pilot pressure is provided, and the ascending pilot valve 41AP and the lowering pilot valve 41BP are each provided with an electromagnetic solenoid 41A.
S, 41BS, the opening degree changes in direct proportion to the control current value supplied to BS to change the pilot pressure.
A, It is constituted so that the opening of each of the descending control valves 41B can be adjusted.

A control mode for the electromagnetic flow control valve 41 will be described. The control current value is changed by changing the duty ratio D. The control current value for supplying the required hydraulic oil flow rate is determined by comparing the set value by the above-described tillage depth setting device 44 with the detection value from the float sensor S. Determined based on the deviation. When the control current value is determined, the duty ratio D is determined, and the electromagnetic flow control valve 41 is controlled at the duty ratio D. When the engine speed decreases in the control of the electromagnetic flow control valve 41, the duty ratio D
Is corrected to a large value, and the opening degree is corrected by the control current value based on the correction duty ratio D ′, thereby preventing the supply flow rate from decreasing. An engine speed detection sensor 31 is provided as a sensor for detecting the engine speed.

The above control can be rewritten as a flow as follows. As shown in FIG. 4, the set value of the tillage depth from the tillage depth setting device 44 and the detection value from the float sensor S are taken in and compared (# 1 to # 3). When the tillage setting value exceeds the detection value, the ascending operation is performed. In this case, the valve opening for obtaining the required flow rate is uniquely determined by the duty ratio D. The ascending pilot valve 41AP is controlled by the duty ratio D. However, it is determined whether or not the engine speed has decreased, and if the engine speed has decreased, the duty ratio D is corrected so as to increase. Control is performed with the correction duty ratio D '. If the engine speed has not decreased, the duty ratio D is maintained (# 4 to # 4).
# 8). When performing the descending operation, the descending pilot valve 41BP is controlled by the duty ratio D according to the deviation between the set value and the detected value (# 9 to # 10).

The relationship between the supply oil flow rate of the electromagnetic flow control valve 41 and the duty ratio has the following characteristics.
It will be incorporated in the control described above. As shown in FIG. 3A, in a state where the engine speed is maintained at the maximum speed, the duty ratio and the flow rate of the working oil supplied from the electromagnetic flow control valve 41 are equal to the amount of the supply oil from the pump 30. Since it is stable, it maintains a certain proportional relationship. On the contrary,
As shown in FIG. 3B, when the engine speed is lower than the maximum engine speed, the duty ratio is equal to or higher than a certain value D ₁ to D ₁ .
When taking the D ₂ is fed hydraulic fluid flow rate is lowered collapses proportional relationship. Accordingly, as shown in FIG. 3 (c), when the engine speed occurs is necessary to apply a correction to the reduced duty ratio takes a large value as the duty ratio, from the duty ratio D ₁ until the duty ratio D ₂ Correction is performed so as to increase only with respect to the duty ratio.

Although the setting and correction of the duty ratio for the electromagnetic flow control valve 41 in the automatic lifting control have been described above, when the control is performed by the manual control means 40C, the lever sensor 43A of the planting clutch lever 43 is used.
Corresponds to the plowing depth setting device 44, and although not shown, a lift arm angle sensor for detecting the elevation angle of the lift arm that drives the link mechanism 4 corresponds to the float sensor 39. In addition, when the ascent / descent operation lever 47 is used to perform the ascent operation,
A duty ratio is determined based on a deviation between the lift arm angle sensor and an upper limit sensor (not shown).

The following control can be performed in addition to the above control. When the engine speed is determined, the discharge rate of the pump is uniquely determined. Here, the discharge amount of the pump is calculated from the detected value of the engine rotation. If the hydraulic oil flow to be supplied from the electromagnetic flow control valve 41 is smaller than the calculated amount of the pump, the duty ratio is maintained. Control operation of the electromagnetic flow control valve 41. On the contrary, the discharge amount of the pump is determined by the electromagnetic flow control valve 4 based on the detected value of the engine rotation.
If the hydraulic oil flow to be supplied from 1 is large, a correction is made to reduce the duty ratio, and control is performed with the corrected duty ratio.

[Other Embodiments] Other embodiments of the present invention will be listed below. As a control mode for changing the attitude of the working device, the rolling control may be performed using a rolling cylinder instead of the rolling motor 42 to correct the duty ratio. Although a leveling float is used as a grounding sensor,
The grounding sensor may be provided separately from the leveling float. The electromagnetic type flow control valve may be a single electromagnetic control valve capable of ascending and descending. The invention of the present application can be applied to raising and lowering control of a tilling device and the like other than the seedling planting device 2.

[Brief description of the drawings]

FIG. 1 is an overall side view of a rice transplanter.

FIG. 2 is a control block diagram.

FIG. 3 is a correlation diagram between a duty ratio and a supply hydraulic fluid flow rate of an electromagnetic flow control valve.

FIG. 4 is a control flow for correcting a duty ratio.

FIG. 5 is a configuration diagram showing an electromagnetic flow control valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Traveling body 2 Working device 3 Hydraulic actuator 6 Engine 30 Pump 40 Control means 41 Electromagnetic flow control valve D Duty ratio

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2B304 KA08 KA13 KA17 LA02 LA04 LA09 LB13 LC04 LC05 MA02 MA06 MB02 MC08 MD03 PC17 PD02 PD07 PD15 PD19 PD24 QA02 QB19 3H089 AA27 BB17 CC01 DA02 DA13 DB12 EE39 FF10 GG02 JJ17

Claims (3)

[Claims] A working device is connected to a traveling machine body via a hydraulic actuator so as to be able to change its posture, and a pump driven by an engine and an electromagnetic type for controlling an amount of hydraulic oil to be supplied from the pump to the hydraulic actuator. A flow control valve is provided, and control means is provided for setting a control current of the electromagnetic flow control valve by a duty ratio and adjusting a valve opening to set a supply hydraulic oil amount of the electromagnetic flow control valve. A work vehicle attitude control device, comprising: a correction means for correcting the rotation speed of the engine to be lower than a predetermined rotation speed by increasing a duty ratio to suppress a decrease in a supplied hydraulic oil amount. Attitude control device. 2. A pump which is driven by an engine and an electromagnetic flow rate which controls an amount of hydraulic oil supplied from the pump to the hydraulic actuator, while a working device is connected to the traveling machine body via a hydraulic actuator so as to be able to change its posture. A control valve that is provided with a control means for setting a control current of the electromagnetic flow control valve by a duty ratio and adjusting a valve opening to thereby set a supply hydraulic oil amount of the electromagnetic flow control valve; A vehicle attitude control device, wherein when the rotation speed of the engine is lower than a predetermined rotation speed, if the duty ratio is large, the duty ratio is further increased to correct the supply hydraulic oil amount so as to suppress the reduction. Work vehicle attitude control device comprising means. 3. A pump driven by an engine and an electromagnetic flow rate controlling an amount of hydraulic oil supplied from the pump to the hydraulic actuator, wherein the working device is connected to the traveling machine body via a hydraulic actuator so as to be freely changeable in posture. A control valve that is provided with a control means for setting a control current of the electromagnetic flow control valve by a duty ratio and adjusting a valve opening to thereby set a supply hydraulic oil amount of the electromagnetic flow control valve; An attitude control device for a vehicle, wherein the duty ratio is determined based on a flow rate characteristic of the engine speed and a pump discharge amount, as compared with a pump discharge amount obtained based on a measured value for the engine speed. When the hydraulic oil amount is a small flow, the duty ratio is maintained, and the duty ratio is compared with the determined pump discharge amount. Hydraulic oil amount determined by the in the case of large flow rate, work vehicle attitude control device comprising a correction means for correcting to reduce the duty ratio.