JP2000157018A - Rice transplanter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rice transplanter enabling planting operation of high planting accuracy with both float function and planting depth maintained at respective constant levels. SOLUTION: In this rice transplanter so designed as to be equipped with a lift sensor 79 for detecting the change in the distance between a planting section and the surface of a paddy field and a hydraulic lift control mechanism for maintaining a set planting depth through the lift control on the planting section based on the detection by the sensor 79, there are also equipped a planting depth setting means steplessly enabling the setting change for planting depth within a relevant setting range and a means 100 for detecting the travel working status of the main machine, and according to the status, the set value of planting depth is changed and corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects a change in the distance between a planted portion and a rice field from a change in the inclination angle of a center float, and controls the vertical movement of the planted portion to control the planting depth of the planted portion. Related to a rice transplanter adapted to maintain a constant.

[0002]

Conventionally, when the running speed of the airframe increases, the front of the float is lifted by the reaction force of the water flow and the topsoil, and the planting elevation control is performed. Therefore, the hydraulic sensitivity of the hydraulic elevation control mechanism ( The target inclination angle of the center float is corrected to the insensitive side (center float tends to move up), so that the planting depth is kept constant by preventing shallow planting due to the rising of the planting part at high speed. There are means. In addition, even when the machine is tilted in the front-rear direction due to head-up or head-down during work, the target tilt angle of the float changes, and the hydraulic sensitivity becomes insensitive or sensitive, and the plant is deeply planted or shallowly planted. Therefore, there is a means for correcting the hydraulic sensitivity to a sensitive or insensitive side.

However, in the case of such a correction only for the hydraulic sensitivity, since the inclination of the float changes from the standard,
There has been a problem that the leveling by the float and the effect of eliminating the traces of the wheels do not function properly. For this reason, for example, in Japanese Utility Model Publication No. 7-37458, when the running speed becomes higher than a certain value in conjunction with the vehicle speed change mechanism, the planting depth is changed to the deep planting side.
There is a means to prevent shallow planting, but in this case, the planting depth is not changed in the low-speed region, so the planting tendency tends to be shallow in the low-speed region and the planting accuracy decreases. There is.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention provides an elevating sensor for detecting a change in the distance between a planted portion and a rice field, and performing a set planting operation by performing elevation control of the planted portion based on the detection of the elevating sensor. In a rice transplanter equipped with a hydraulic raising / lowering control mechanism for maintaining the planting depth, a planting depth setting means capable of changing the planting depth in a set range in a stepless manner, and an operation for detecting a traveling work state of the machine Detecting means is provided to change and correct the setting value of the planting depth according to the running work state of this machine, and when the running work state such as the vehicle speed and front / rear posture of this machine changes, the float inclination posture is appropriate In this state, only the reference value of the planting depth is appropriately corrected to enable a good planting operation while keeping the planting depth constant.

Further, a vehicle speed sensor for detecting the running speed of the machine is provided, and the set value of the planting depth is changed and corrected in accordance with the running speed of the machine, and the planting depth is set when the machine is running at high speed. Only the reference value of the depth is corrected to the deep planting side, thereby enabling a good planting operation with the planting depth being constant.

Further, a sensitivity setting device for adjusting the hydraulic sensitivity of the hydraulic raising / lowering control mechanism is provided, and while the hydraulic sensitivity is kept at the standard, the planting section is controlled to move up and down to the set planting depth so that the float is always in the standard posture. In this case, the planting work can be carried out with the planting depth kept constant by leveling the surface of the rice field and erasing the traces of the wheels with an appropriate contact pressure.

Further, planting detecting means for detecting a planting operation state is provided, and an actuator for correcting the planting depth by driving an actuator of the planting depth setting means only in the planting operation state. Only when the actuator is driven, the frequency of use of the actuator is reduced (battery consumption is reduced and the service life is extended) to improve the durability of the actuator and maintain stable planting accuracy.

Further, when the actuator enters the dead zone of the target value, the drive output to the actuator is inhibited until a certain time elapses, thereby reducing the frequency of use of the actuator and preventing hunting of the operation of the actuator. Thus, the operation stability is improved.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a side view of a riding rice transplanter, and FIG. 2 is a plan view of the same. In FIG. 1, (1) is a traveling vehicle on which an operator rides, and an engine (2) is mounted on a body frame (3). A front paddle traveling wheel (6) is supported in front of a case (4) via a front axle case (5), and a rear axle case (7) is connected to a rear portion of the transmission case (4). 7) Support the paddy field rear wheel (8). A spare seedling mount (10) is attached to both sides of the hood (9) covering the engine (2) and the like, and the step of getting on and off (1)
The transmission case (4) and the like are covered by a body cover (12) on which an operator rides via 1), and a driver's seat (13) is mounted on the upper part of the body cover (12). Then, a steering handle (14) is provided at the rear of the hood (9).

[0010] In the drawing, (15) is a planting section provided with a seedling mounting table (16) for planting six rows and a plurality of planting claws (17). Forward tilting seedling platform (1
6) is supported on a planting case (20) via a lower rail (18) and a guide rail (19) so as to be reciprocally slidable right and left, and a rotary case (21) is rotated at a constant speed in one direction. A pair of claw cases (22) and (22) are supported at the case (20) and symmetrically positioned around the rotation axis of the case (21), and the claw case (22) is provided.
(22) Attach the planting claws (17) and (17) to the tip. A hitch bracket (24) is provided on the front side of the planting case (20) via a rolling fulcrum shaft (23), and is provided via a lifting link mechanism (27) including a top link (25) and a lower link (26). A hitch bracket (24) is connected to the rear side of the traveling vehicle (1), and the link mechanism (2)
7) A hydraulic lift cylinder (28), which is a hydraulic lift control mechanism for raising and lowering the planting section (15), is connected to the lower link (26), and the front and rear wheels (6) and (8) are driven to travel. At the same time as moving, seedlings for one plant are taken out from the seedling mounting table (16) which is reciprocally slid left and right by the planting claws (17), so that the seedlings are continuously planted.

In the drawing, (29) is a main speed change lever, (3)
0) is a planting lever which is also a sub-transmission lever, (31) is a sensitivity setting device, (32) is a main clutch pedal, (33) (3)
3) is a left and right brake pedal, (34) is a two-floor leveling center float, (35) is a two-floor leveling side float, and (36) is a six-floor side fertilizer.

Further, as shown in FIGS. 3 and 4, the vehicle body frame (3) is inclined to a front low and rear high (an inclination angle of about 4 degrees).
The gantry (37) is fixed integrally on the front upper surface, and the gantry (3)
7) On the upper surface of the anti-vibration rubber (38) and the engine stand (3)
9) The engine (2) is mounted on the engine, and a fuel tank (40) is mounted on the left side of the engine (2), and a muffler (41) is mounted on the right side of the engine (2).
A battery (43) is mounted substantially at the center on the front end side of the body frame (3).

Further, a case base (44) is integrally fixed to the body frame (3), a steering case (45) is mounted on the case base (44), and a handle cylinder (4) is provided.
6) The steering shaft (14a) of the steering handle (14) to be inserted into the steering case (45) is set up on the upper surface of the steering case (45) substantially at the center between the left and right body frames (3) and (3). ) Output shaft (4
7), and a steering arm (48) for turning the left and right front wheels (6) and (6) is attached to the output shaft (47).

A substantially horizontal cylindrical bearing body (49) is welded and fixed to the lower side of the engine stand (39) below the engine (2), and the countershaft (49) is attached to the bearing body (49). The counter pulley (5) is provided at the front end of the counter shaft (50) for inserting and supporting the bearing body (49) forward.
1) Attach, and right and left body frames (3) (3)
An engine output shaft (52) protrudes in front of the engine (2) at substantially the upper center therebetween, and an output pulley (53) is attached to the output shaft (52). The output pulley (53) is connected to the counter pulley (53). 51) via a V-belt (54).

Further, a rear axle case (7) is bolted and fixed to the rear end of the vehicle body frame (3), and a transmission case (4) rear surface is connected and fixed to a front surface of the rear axle case (7). ), A clutch case (55) is integrally formed on the right front surface, a continuously variable belt transmission case (56) right rear surface is fitted and fixed to the front surface of the clutch case (55), and a hydraulic pump (actuated by a lifting cylinder (28)). 57) is fixed to the left rear surface of the belt transmission case (56), and the respective cases (4), (55) are located lower than the upper surface between the left and right body frames (3) (3) in the form of a square pipe. (56) and the hydraulic pump (57) are suspended and fixed, and the transmission shaft (58) with universal joint is connected to the counter shaft (5).
0) It is provided between the rear end and the belt transmission case (56) to transmit the output of the engine (2) to the belt transmission case (56), and between the front axle case (5) and the transmission case (4). ) Is provided to transmit the shift output of the transmission case (4) to the front and rear wheels (6) and (8) via the respective axle cases (5) and (7).

As shown in FIGS. 5 to 8, a pitching fulcrum shaft (60) for swingably supporting the front portion of the center float (34) up and down is provided on a bracket (61) on the rear upper surface of the float (34). The base of a planting depth adjusting link (63) is fixedly mounted on a planting depth adjusting fulcrum shaft (62) rotatably supporting the planting case (20). ) Is connected to the pitching fulcrum shaft (60).

An intermediate portion of the output link (66) is rotatably supported on a support shaft (65) supported on the side of the planting case (20) via a fixed arm (64a), and the adjustment fulcrum shaft (62). ), A rear end of an output link (66) is connected to a distal end of a swing arm (67) having a base end fixed thereto via a coupling pin (68), and a shaft (69) at the front end of the output link (66). Bracket (71) fixedly attached to the front upper surface of the center float (34)
Shaft (72) and the shaft (7
3) are connected via a swing link (74).

Further, the middle of the sensor link (75) is rotatably supported on the support shaft (65), and the sensor link (7) is pivotally supported.
5) The shaft (76) at one end and the shaft (77) at the other end of the elevating link (70) are connected by an interlocking link (78), and the fixed arm (64b) is connected to the planting case (20). The detection shaft (82) at the other end of the sensor link (75) is engaged and connected to the long hole (81) of the detection arm (80) of the potentiometer type lifting sensor (79) supported via When the planting depth changes due to a change in the depth or the like, the planting sensor (79) detects the change.

As shown in FIGS. 9 to 11, a planting depth adjusting lever (83), which is a planting depth setting means for setting a standard planting depth and having a base end fixed to the fulcrum shaft (62), is an actuator. The drive control is appropriately performed by a certain planting motor (84). The motor mounting base is mounted on a transmission pipe (85) on the right side of the central planting case (20) via a mounting plate (86) and a side plate (87). An adjustment lever (83) is attached to the U-shaped engaging metal fitting (91) of the mover (90) to be fixed to the motor mounting base (88) and coupled to the rotary screw shaft (89) of the motor (84) of the motor mounting base (88). ) Is engaged with one end of an L-shaped engagement shaft (92), and when the moving element (90) moves vertically along the screw shaft (89) by driving of the motor (84), the adjusting lever is used. (83) is swung up and down to pivot the fulcrum shaft (62). It is configured to perform adjustment of the reference planting depth.

The adjusting lever (83) is divided into a base frame portion (83a) fixed to the fulcrum shaft (62) and a distal end operating portion (83b) fixed to the engaging shaft (92). The operating portion (83b) is connected to the tip of the frame portion (83a) via a rotating shaft (93) so as to be swingable left and right, and the engaging shaft (92) of the frame portion (83a) is connected to the operating portion. A fulcrum spring (95) centering on the rotating shaft (93) is extended between the shaft (94) of (83b), and the operating unit (83b) is moved rightward about the rotating shaft (93). Oscillating and engaging shaft (92) from engaging metal fitting (91)
It is configured to allow the manual operation of the adjustment lever (83) when the is released. In addition, a lever positioning notch (88b) is formed on one side of the lever guide hole (88a) of the mounting base (88), and the adjustment lever (8) is formed.
At the time of manual operation 3), a positioning plate (83c) fixed to the operation section (83b) is engaged with the notch (88b) to fix the position of the adjustment lever (83).

Further, the operating portion (83b) of the adjusting lever (83) is formed to be short and is compactly arranged in a cover (96) which is openably and closably fixed to a motor mount (88). The mounting base (88) is provided with a potentiometer type feedback sensor (98) for detecting the movement position of the sensor pin (97) of the frame portion (83a) via the actuator (98a) so as to detect the planting depth position. It is composed. The moving element (9)
0) is provided with a guide roller (90a) to be inserted into the movement guide hole (88c) of the mounting base (88), and a screw shaft (8) is provided.
9) The co-rotation of the moving element (90) during rotation is prevented.

When the planting depth is changed centering on the fulcrum shaft (62) by the planting depth motor (84) or the adjusting lever (83), the vertical position of the pitching fulcrum shaft (60) and the front end of the output link (66) are changed. The vertical movement position of the shaft (69) is made substantially the same so that the output of the elevation sensor (79) is not changed even if the planting depth is changed.

On the other hand, an engine rotation sensor (99) for detecting the number of rotations from the engine (2) transmitted via a transmission shaft (58) is provided on the input shaft portion of the transmission case (56).
The input shaft of the front axle case (5) is provided with a vehicle speed sensor (100) as work detecting means for detecting a traveling output from the transmission case (4) transmitted via a transmission shaft (59). Body cover (1
2) A tilt sensor (10) such as a pendulum type or a capacitance type for detecting the forward / backward tilt of the traveling vehicle (1) is provided substantially at the center of the rear part.
1) is provided.

As shown in FIGS. 5 and 12, a potentiometer type elevation position sensor (103) is installed on a left body frame (3) via a sensor mounting plate (102).
The piston rod (28a) of the lifting cylinder (28)
A detection plate (105) is fixed to a lift arm (104) connecting the tip and the lower link (26), and a detection axis (106a) at the tip of the detection arm (106) of the position sensor (103) is detected. (105) by engaging with the long hole,
When the planting section (15) is moved up and down by the elevation cylinder (28), the elevation position is detected by a sensor (103).

As shown in FIGS. 3 and 13, the vehicle speed sensor (100) is provided on the outer periphery of a spline joint (107) connecting the front wheel transmission shaft (59) and the input shaft (5a) of the front axle case (5). A vehicle speed, which is a traveling output, is calculated by detecting a rotation pulse of the fixed gear (108), and a vehicle speed sensor (100) such as a rotation sensor (proximity switch).
And a sensor base (1) for mounting the sensor (100).
09) is detachably fixed via a bolt (111) to a mount (110) of an axle case (5) fixedly mounted on a vehicle body frame (3), so that the vehicle speed sensor (100) can be easily mounted and replaced. As a result, the maintenance and inspection work is simplified, and the inconvenience of malfunction due to chips, such as a sensor directly attached to the transmission case (4), is eliminated, and stable detection accuracy is maintained. .

As shown in FIG. 14, the supply hydraulic circuit of the hydraulic pump (112) driven by the engine (2) is branched into a high-pressure oil passage (114) and a low-pressure oil passage (115) by a flow control valve (113). The steering valve unit (11) that switches the steering valve (117) of the steering cylinder (116) with the steering handle (14).
8) and a solenoid type up / down valve (119)
(120) The lifting valve unit (121) that drives the lifting cylinder (28) by the operation is connected to the high pressure oil passage (11).
4) and a horizontal valve unit (12) having a horizontal operation solenoid valve (123) of a horizontal cylinder (122) for controlling the horizontal inclination posture of the planting section (15).
4) is provided in the low-pressure oil passage (115), and the planting portion (15) is provided.
Is controlled by exciting the valves (119) and (120) and exciting the descending solenoids (125) and (126).

As shown in FIG. 15, there is provided a controller (128) for making an output connection to a relay circuit (127) of the planting motor (84) and the solenoids (125) (126). The down switch (129) and the up switch (13), which are planting detection means for detecting the planting down and up positions of the lever (30), respectively.
0) and each of the sensors (79) (98) (99) (10)
0), (101) and (103), a planting depth setting device (131) for setting a reference planting depth, and a sensitivity setting for setting a hydraulic pressure raising / lowering sensitivity (a target value) of a lifting / lowering cylinder (28) according to a field surface hardness. The controller (128) is connected to the controller (128) through input so as to perform a lifting / lowering control for maintaining a constant planting depth.

The present embodiment is constructed as described above, and as shown in FIGS. 16 and 17, the down switch (1
29) When the output values of the sensitivity setting device (131), the inclination sensor (101), and the vehicle speed sensor (100) are read by the controller (128) during the planting operation with the ON (planting down) state, In the sensor (101), the sensitivity becomes sensitive or insensitive depending on the front up or down state of the machine, and in the vehicle speed sensor (100), the sensitivity becomes insensitive depending on the speed at high speed. The correction to be changed is added to the standard sensitivity (standard tilt angle of the center float) set by the sensitivity setting device (131), and the target sensitivity is calculated. When the work is performed at the standard sensitivity where no correction is performed, the sensor (V) read by the elevation sensor (79)
Until the standard sensitivity (V1) set by the sensitivity setting device (31) matches (the tilt angle of the center float (34) matches the standard tilt angle), the raising and lowering cylinder (28) moves the planting section (15). The descending and ascending control is performed, and thereafter, the ascending / descending control of the planting section (15) is performed so that the target planting depth set as a target is kept constant (V = V1).

On the other hand, when a correction is applied to the standard sensitivity, this sensitivity correction is calculated as a planting depth correction amount in the data diagram of FIG. 17 (for example, a planting depth correction amount of 2-3 mm for a float inclination angle of 1 degree). ), Correction amount (center float (3
(4) When the deviation between the current position and the target position is on the deep planting or shallow planting side, the planting motor (84) is operated while the standard sensitivity (standard inclination angle) of the center float (34) is kept constant. The planting is driven by the deviation toward the shallow planting or deep planting side to keep the planting depth constant. When the reference planting depth changes in accordance with the working conditions such as the vehicle speed and the posture of the machine, the float (34) is corrected with only the reference planting depth while keeping the inclination posture constant. (34)
The planting depth is maintained constant while the leveling / wheel erasure function according to (35) is correctly operated.

FIGS. 18 and 19 show an example of a configuration in which the setting value of the planting depth is corrected in accordance with the low and high speeds of the traveling speed, and is set by the planting depth setting device (131). When the setting value of the planting depth is input to the controller (128), it is stored, and when the setting value is changed thereafter, these are updated and stored, and during the planting operation (down switch (129)
Is turned on), the traveling speed is read into the vehicle speed sensor (100), and when the speed is lower than the standard speed, the planting depth correction amount according to the speed is calculated, and the planting depth motor (84) according to the correction amount is calculated. ) (In FIG. 19, shallow planting side at a speed lower than 0.8 m / s, deep planting at a speed higher than 0.8 m / s).
The planting operation is performed so that the planting depth which is not affected by the traveling speed is always maintained constant. As shown by the broken line in FIG. 19, the correction ratio at high speed may be made larger than that at low speed.
s or more).

FIGS. 20 and 21 show a sensitivity setting device (31) during the planting operation (the down switch (129) is on).
Based on the output value of the vehicle speed sensor (100) and the planting depth setting unit (131), the lever position of the adjustment lever (83) that is set to the planting depth set value is corrected, and the planting depth target value is corrected. (V2) is calculated, and a fixed time (T) of a timer built in the controller (128) (for example, T = 200 milliseconds)
Prohibits this output, and after a lapse of a predetermined time (T), the sensor value (V3) detected by the feedback sensor (98)
The planting depth motor (84) is driven forward or reverse in accordance with the deviation (V2-V3) between the (current adjustment lever (83) position) and the target value (V2), so that the planting depth is shallowly or deeply planted. By correcting and changing the set value of the planting depth to maintain the planting depth constant, the frequency of use of the planting motor (84) is reduced (suppression of battery consumption and longer life), and Planting motor (8
The hunting of the operation 4) is prevented, and the planting depth correction control is performed in a smooth operation to improve the stability of the control.

[0032]

As is apparent from the above embodiments, the present invention is based on the elevation sensor (79) for detecting a change in the distance between the planting section (15) and the rice field, and the detection of the elevation sensor (79). In a rice transplanter equipped with a hydraulic raising and lowering control mechanism (28) for controlling the raising and lowering of the planting section (15) to maintain the set planting depth, the setting of the planting depth is steplessly changed within the set range. A possible planting depth setting means (83) and a work detecting means (100) for detecting the running work state of the machine are provided, and the set value of the planting depth is changed and corrected according to the running work state of the machine. Therefore, when the traveling work state such as the vehicle speed and the front-rear posture of the machine changes, only the reference value of the planting depth is properly adjusted while maintaining the inclination posture of the floats (34) and (35) properly. By compensating, it is possible to perform good planting work while keeping the planting depth constant. It is intended.

A vehicle speed sensor (100) for detecting the running speed of the machine is provided to change and correct the set value of the planting depth according to the running speed of the machine. During traveling, only the reference value of the planting depth is corrected to the deep planting side, so that a good planting operation with the planting depth kept constant can be performed.

Further, a sensitivity setting device (31) for adjusting the hydraulic sensitivity of the hydraulic raising / lowering control mechanism (28) is provided, and the planting section (15) is moved up and down to the set planting depth while keeping the hydraulic sensitivity at the standard. Float (34) (35)
Can be maintained in a standard posture, leveling the surface of the rice field and erasing the tracks of the wheels with an appropriate contact pressure to enable good planting work with a constant planting depth. .

Further, planting detecting means (129) for detecting a planting operation state is provided, and the actuator (84) of the planting depth setting means (83) is driven only during the planting operation state. Actuator (8
4) can be driven only during the planting operation state, thereby reducing the frequency of use of the actuator (84) (reducing battery consumption,
The life of the actuator (84) can be improved, and the stability of the planting accuracy can be stably maintained.

When the actuator (84) enters the dead zone of the target value (V2), the drive output to the actuator (84) is inhibited until a certain time (T) elapses. 84), the hunting of the operation of the actuator (84) can be prevented, and the operation stability can be improved.

[Brief description of the drawings]

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

FIG. 2 is an overall plan view of the rice transplanter.

FIG. 3 is an explanatory side view of the traveling vehicle body.

FIG. 4 is an explanatory plan view of a traveling vehicle body.

FIG. 5 is an explanatory side view of the planting section.

FIG. 6 is an explanatory plan view of a float portion.

FIG. 7 is an explanatory plan view of a center float portion.

FIG. 8 is an explanatory side view of a center float portion.

FIG. 9 is an explanatory side view of a planting depth adjusting unit.

FIG. 10 is an explanatory front view of a planting depth adjusting unit.

FIG. 11 is an explanatory plan view of a planting depth adjusting unit.

FIG. 12 is an explanatory view of mounting a vertical position sensor.

FIG. 13 is an explanatory view of mounting a vehicle speed sensor.

FIG. 14 is a hydraulic circuit diagram.

FIG. 15 is a control circuit diagram.

FIG. 16 is a flowchart of planting depth control.

FIG. 17 is a diagram showing a relationship between hydraulic sensitivity and a planting depth correction amount.

FIG. 18 is a flowchart of planting depth correction control.

FIG. 19 is a diagram showing a relationship between a traveling speed and a planting depth correction value.

FIG. 20 is a flowchart of planting depth correction control.

FIG. 21 is a diagram showing a relationship between a planting depth motor and a feedback sensor.

[Explanation of symbols]

 (15) Planting part (28) Hydraulic elevating cylinder (hydraulic elevating mechanism) (31) Sensitivity setting device (79) Elevating sensor (83) Adjusting lever (planting depth setting means) (84) Planting motor (actuator) (100) ) Vehicle speed sensor (129) Down switch (planting detection means)

Continued on front page F-term (reference) 2B062 AB01 BA22 BA62 CA03 CA04 CA06 CA07 CA09 CA10 CB04 2B063 AA08 AB01 AB03 BB13 CA04 CA07 CA10 CB02 CB06 CB11 2B304 KA14 LA02 LA09 LB05 LB16 LC04 LC14 MA04 MB02 MC08 MC13 MD04 Q08 PA08 QB17 RA27

Claims (5)

[Claims] 1. A lifting sensor for detecting a change in the distance between a planting portion and a rice field surface, and a hydraulic lifting control for performing a lifting control of the planting portion based on the detection of the lifting sensor to maintain a set planting depth. In a rice transplanter equipped with a mechanism, a planting depth setting means capable of changing the setting of the planting depth steplessly within a setting range, and a work detecting means for detecting a traveling work state of the machine, and A rice transplanter characterized in that a setting value of a planting depth is changed and corrected according to a traveling work state. 2. The apparatus according to claim 1, further comprising a vehicle speed sensor for detecting a traveling speed of the machine, wherein the setting value of the planting depth is changed and corrected in accordance with the traveling speed of the machine. Rice transplanter as described. 3. A sensitivity setting device for adjusting a hydraulic sensitivity of a hydraulic raising / lowering control mechanism is provided, and the planting section is controlled to move up and down to a set planting depth while keeping the hydraulic sensitivity at a standard. The rice transplanter according to claim 1, wherein 4. The rice transplanter according to claim 1, further comprising planting detection means for detecting a planting operation state, and driving the actuator of the planting depth setting means only during the planting operation state. . 5. The rice transplanter according to claim 4, wherein when the actuator enters a dead zone of a target value, a drive output to the actuator is inhibited until a predetermined time elapses.