JP2001128517A - Rice transplanter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the high velocity travel of a rice transplanter, when the rice transplanter is moved in a field in a state that a planting section is lowered and not driven. SOLUTION: This rice transplanter in which the velocity ratio of a continuously variable speed mechanism (64) for changing a work speed is controlled in interlock with an engine rotation speed (N) which can be changed with axle operation members (87), (94), characterized in that the velocity ratio of the continuously variable speed mechanism (64) is interlocked with the engine rotation speed (N), when a planting section (15) is lowered or when a planting clutch (72) is connected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rice transplanter having, for example, a seedling mounting table and planting claws for continuously performing seedling planting operations.

[0002]

Conventionally, in changing the working speed of a rice transplanter, an accelerator operation performed by an engine,
There are a main shifting operation performed in the transmission case and a sub-shifting operation performed by activating the continuously variable transmission mechanism at the time of the "planting" operation of the main transmission. The sub-shift operation is usually performed by two systems. However, such two-system shift operation has a disadvantage that the operation is complicated and operability is poor. Therefore, there is a means in which the accelerator operation and the auxiliary speed change operation are integrated into one to perform an interlocking operation. However, such an interlocking operation is usually performed when the planting section is in the down state and the planting clutch is in the on state. This is done only during the work. For this reason, when the planting clutch is engaged with the planting portion lowered, the work speed increases in conjunction with the sub-shift in response to the accelerator operation. However, the speed does not increase only when the planting portion is in the down state. When moving in a field with the 下降 is lowered and held (idling), there is an inconvenience that the traveling speed is low and the work efficiency is poor.

[0003]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a rice transplanter in which the speed ratio of a continuously variable transmission mechanism for changing a working speed is interlocked based on an engine speed changed by an accelerator operating member. In the working condition in which the planting section is lowered or the planting clutch is engaged, the interlocking control between the engine speed and the speed ratio of the continuously variable transmission mechanism is performed, and the planting clutch is moved while the planting section is lowered. It is intended to improve the work efficiency by enabling high-speed running when moving in the field (idle running) after being cut off.

Further, when the planting section is operated to be lowered from the neutral position to the lowering position, a gradual increase control for gradually increasing the speed ratio of the continuously variable transmission mechanism is performed to lower the planting section. For a certain period of time in a low speed range to facilitate alignment before planting.

Further, when the planting section is operated to descend from the neutral position to the lowering position, a slow gradual acceleration control for gradually increasing the speed after maintaining the low speed for a certain period of time is performed, so that the planting section is lowered. A certain waiting time and a certain time after the waiting are caused to travel in a low-speed region, and the setting before planting and the like are accurately performed.

Further, when the accelerator operation member is operated or when the engine speed is changed to a certain speed or more, the slow acceleration control is released and the control is shifted to the interlocking control of the engine speed and the speed ratio of the continuously variable transmission mechanism. If the engine speed changes to the high-speed side due to manual accelerator operation during slow acceleration control before planting, the speed ratio will follow this and change to the high-speed side to improve work efficiency. It is to let.

[0007]

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 axle case (5) 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). Then, a spare seedling mounting table (10) is mounted on both sides of the hood (9) covering the engine (2) and the like, and the step of getting on and off (1) is performed.
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), and the driver's seat (13) is located in front of the driver's seat (13). Then, a steering handle (14) is provided at the rear of the hood (9).

[0008] In the figure, (15) is a planting section provided with a seedling mounting table (16) for six-row planting 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 a hitch bracket (27) including a top link (25) and a lower link (26) is provided. A hitch bracket (24) is connected to the rear side of the traveling vehicle (1), and the link mechanism (2)
7) A hydraulic lifting cylinder (28) 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 and moved, and at the same time,
A seedling for one plant is taken out from a seedling mounting table (16) that is reciprocally slid left and right by a planting claw (17), and the seedling planting operation is continuously performed.

In the drawing, (29) is the main speed change lever, (3)
0) is a planting lever, (31) is a sensitivity setting device, (32) is a main clutch pedal, (33) and (33) are left and right brake pedals, (34) is a two-floor leveling center float, and (3)
5) is a side float for leveling two rows, and (36) is a side fertilizer for 6 rows.

Further, as shown in FIGS. 3 and 4, the vehicle body frame (3) is tilted to a front low and rear high (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 cylindrical bearing (49), which is substantially horizontal in the front-rear direction, is welded and fixed to the lower side of the engine stand (39) below the engine (2), and a counter shaft (49) is attached to the bearing (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 FIG. 7, an input / output pulley (61) (6) for changing the winding ratio in a stepless manner by changing the winding diameter by operating an electric transmission motor (electric cylinder) (60).
2) and a belt-type continuously variable transmission mechanism (64), which is a sub-transmission portion composed of a V-belt (63), is connected to a belt transmission case (5).
6), a multi-disc friction dry clutch (65) which is intermittently operated by a main clutch pedal (32) is installed in the clutch case (55), and a belt shift case (5).
6) The output shaft (66) of the transmission case (4) is connected to the input shaft (67) of the transmission case (4) via the clutch (65) so that the speed change motor (60) can be used to reduce the planting work speed, which is the auxiliary speed change. It is configured to shift.

A traveling output shaft (69) is connected to the input shaft (67) via a traveling transmission gear mechanism (68).
The traveling output shaft (69) is connected to the front and rear wheels (6) and (8) via front and rear wheel transmission shafts (59) and (70) to drive the front and rear wheels (6) and (8) and to drive the input shaft ( 67) PTO transmission gear mechanism (71) and planting clutch (72)
The PTO shaft (73) is connected via the
3) to drive the planting part (15), and output the PTO shaft (73) near the transmission case (4) to the sprocket (7).
It is configured so that the fertilizer (36) is driven by branching at 4). (75) is the lifting cylinder (28)
Is a hydraulic pump that operates. The speed change motor (6)
0), the speed ratio of the continuously variable transmission mechanism (64) may be changed using an electromagnetically operated hydraulic cylinder. Further, the hydraulic continuously variable transmission mechanism (HS) may be replaced with a belt type continuously variable transmission mechanism (64).
T) may be used.

As shown in FIGS. 5 and 6, the speed change motor (60) is substantially parallel to the inside of the rear portion of the left and right body frame (3) and is integrally connected to the front and rear low and high subframes (76).
To the left sub-frame (76) of the left sub-frame (76).
8) The base end of the transmission motor (60) is vertically movably mounted via the transmission gear (60), and the transmission link (80) is connected to the transmission lever (79) on the front surface of the transmission case (56) in which the continuously variable transmission mechanism (64) is provided. The motor shaft (60a) of the speed change motor (60) is connected via the pulling arm (81), and the speed change lever (79) is operated by the expansion and contraction operation of the motor shaft (60a) by the drive of the speed change motor (60). Continuously variable transmission mechanism (6
4) The speed ratio is changed to change the speed ratio.

The lifting arm (81) pivotally supports an intermediate portion on a left body frame (3) via a horizontal shaft (82) so as to be swingable, and has one end on the motor shaft (60a) and the other end. Are connected to the links (80), respectively, to transmit the shift operation output from the shift motor (60) to the shift lever (79) and to be fixed to the left body frame (3) via the mounting plate (83) and the like. Potentiometer type speed ratio sensor (8
4) The sensor arm (85) and the lifting arm (8)
1) is engaged with the detection shaft (86), and the pulling arm (81) is oscillated by the speed change motor (60) to change the speed ratio of the continuously variable transmission mechanism (64). It is configured to detect by the ratio sensor (84).

As shown in FIGS. 2, 8, and 9, an accelerator pedal (87) serving as an accelerator operating member is disposed on the right outside of the right body frame (3) and near the brake pedal (33). A detection shaft (9) fixed to the tip of a pedal arm (89) fixed to a pedal shaft (88) of the pedal (87).
0) and a sensor arm (91) of a potentiometer type accelerator sensor (91) fixed to the right body frame (3) side.
a) is engaged so as to detect the amount of depression of the accelerator pedal (87) (increase / decrease in engine speed) by the accelerator sensor (91).

The engine (2) throttle section (2) reaches a position corresponding to the sensor value of the accelerator sensor (91).
The engine (92) driven by the accelerator motor (92) is driven by a pickup-type engine rotation sensor (93) that drives the accelerator motor (92) to control the throttle opening of a) and detects the number of revolutions of the engine output shaft (52). 2) When the actual engine speed (N) is detected, the speed change motor (60) is interlocked to the speed ratio position of the continuously variable transmission mechanism (64) set based on the actual engine speed (N). When the engine speed (N) is changed by the operation of the pedal (87), the speed ratio of the continuously variable transmission mechanism (64) is also changed according to the engine speed (N), and the operation of the single pedal (87) is performed. The engine speed (N) and the speed ratio are simultaneously changed in conjunction with each other. An accelerator lever (94) provided on the right outside of the hood (9) also performs an interlocking change in the engine speed (N) and the speed ratio, similarly to the accelerator pedal (87).

As shown in FIGS. 11 and 16, a mode changeover switch (95) for changing the speed ratio of the continuously variable transmission mechanism (64) to the engine speed (N) to a high speed, a medium speed and a low speed mode. The operation lever (96) is provided near the steering handle (14), and the wheel (14b) of the steering handle (14) and the operation column (9) are provided.
7) A lever base (100) is detachably fixed to an outer cylinder (98) of the steering shaft (14a) between the upper panel surface (97a) and the lever base (1) via a bolt (99).
00) via the lever shaft (101) to the operating lever (96)
Is pivotally mounted, and the distal end operating portion (96a) of the operating lever (96) is arranged on the left outside of the handle (14) so as not to protrude outside the left outer surface of the hood (9). 96) is rotated about the lever shaft (101) in a substantially horizontal front-rear direction, so that the rearward direction is close to the driver's seat (13). When the vehicle is set in the forward direction, the mode is switched to the high-speed mode.

As shown in FIG. 10, the accelerator pedal (87) is provided so as to match the direction of rotation of the operator's foot in the driver's seat (13) with a certain angle (θ) from the front-rear vertical line. By tilting the direction of the pedal (87) to the left so that the direction of the foot matches the direction of the pedal (87), the operability of the pedal (87) is improved, and the brake pedal (33) and the accelerator pedal are improved. (8
7) and these pedals (33) (8)
It is configured to prevent the mistake in step 7).

As shown in FIG. 13, a planting down switch (102) which is installed near the planting lever (30) and detects a lowering operation of the planting section (15) by the lever (30). A planting switch (10) for detecting the on / off state of the planting clutch (72) by the planting lever (30).
3), a main clutch switch (104) for detecting the on / off of the main clutch pedal (32), a mode changeover switch (95), and a control by a drive of the accelerator motor (92) via the throttle arm (105). A throttle sensor (106) for detecting the throttle opening of the throttle section (2a), the accelerator sensor (91),
Speed ratio sensor (84) and engine rotation sensor (94)
And a vehicle speed sensor (107) for detecting a vehicle speed from the rotation of the travel output shaft (69) to a controller (108), and a relay circuit (109) connected to the speed change motor (60) and the accelerator motor (92). ), The controller (107) is connected to the control indicator lamp (111) provided on the panel surface (96a), and the engine speed (N) is operated by a single pedal (87) operation.
And the speed ratio of the continuously variable transmission mechanism (64) is changed simultaneously.

As shown in FIG. 12, the planting lever (30) enables the raising and lowering operation of the planting portion (15) and the on / off operation of the planting clutch (72). The planting portion (1) is located between the raised position and the lowered position of (30).
5) is provided at a neutral position for stopping at an intermediate height, and at a lowered position of the planting lever (30), the planting clutch (72) is provided at a planting-off operation position for disengaging the planting clutch (72). The forward swinging end of the planting lever (30) is provided at the planting operation position, and when the planting lever (30) is brought to the planting operation position, the planting section (15) is kept in the lowered state. The planting clutch (72) is provided to be engaged.

The present embodiment is constructed as described above, and as shown in the flow chart of FIG. 14, the planting section (15) during operation of the engine (2) is lowered (the lowering switch (102) is turned on). When done or planting part (15)
Is lowered and the planting clutch (72) is turned on (the planting switch (103) is turned on), timing (T) is started, and the engine rotation sensor (93) and the speed ratio sensor (84) are used. Engine speed (N) and speed ratio (V)
Is input to the controller (108), and FIG.
As shown in the figure, the engine speed is changed from the low speed, medium speed or high speed mode selected by the mode changeover switch (95) (for example, high speed under normal conditions, middle speed or low speed when the running load is within a certain level or more). The optimum target speed ratio (V1) corresponding to (N) is calculated.

Then, as shown by the solid line (S1) in FIG. 15, the speed ratio (V) is reduced to a low speed within a fixed time (T1) (T1 ≒ 4 seconds) from the start of timing when the planting section (15) descends. The speed ratio motor (60) is pulse-driven (intermittently driven) to a more targeted high-speed speed ratio (V1) to perform gradual speed-up control to gradually increase the speed, and is detected by the speed ratio sensor (84). Difference between the actual speed ratio (V2) and the target speed ratio (V1) (| V1-V
2 |) is greater than or equal to the dead zone (V0).
1-V2 |) in the dead zone (V0).
<V0> Continuous speed-up / down control of the speed change motor (60) is performed, and planting is optimally performed in the field condition and the machine condition by the speed ratio according to the engine speed (N) of the engine (2) driven at that time. Work is performed at the work speed.

In this case, in each of the low, medium and high speed modes, the speed ratio of the low speed and high speed constant sections (a) and (b) of the engine speed (N) is set to the lowest speed (L) and the highest speed ( H), the low engine speed (N)
When the speed ratio is maintained at the minimum speed (L) in the constant section (a) of (N = 1700-2000 rpm), the planting operation speed on the low rotation speed side is prevented from lowering by a predetermined value or more, and the engine (2) ), The work speed is maintained at a substantially minimum speed by a speed ratio that maintains a constant value (L) even when the engine speed (N) fluctuates in the low speed range. It is intended to perform good low-speed work.

On the other hand, the engine speed (N) on the high rotation side
When the speed ratio is maintained at the highest speed (H) in the constant section (b) of (N = 3500-3900 rpm), the frequency at which the working speed is reduced in the high rotation range of the frequently used engine (2) is reduced. It is intended to secure a stable work speed and to improve work efficiency.

In a certain section (c) (c = 2000-3500 rpm) which is an intermediate rotation range between the lowest speed section (a) and the highest speed section (b) of the engine speed (N), The speed ratio is changed to the high speed side in proportion to the engine speed (N), and the work speed is accelerated and proportional to the operation amount of the accelerator operation. It is to let.

The mode changeover switch (95) is provided in the low-speed mode when the switch (95) is in the open state (contact is open), and automatically operates when the wiring is disconnected or the terminal is disconnected. Returning to the mode prevents the work from speeding up.

As shown by the solid line (S2) in FIG. 15, the speed ratio (V) is gradually increased (intermittently increased) from the low speed to the target speed ratio (V1) within the time (T1). When the engine speed (N) changes by a predetermined speed (△ N) (for example, a change amount of the engine speed (N) within a certain period of time) by operating the accelerator pedal (87) or the like, the slow acceleration control is performed. Is released and the operation is shifted to the interlocking control to increase the change speed ratio. The artificial operation such as the accelerator pedal (87) is prioritized, and is fixed after the completion of the alignment by lowering the planting portion (15). Even if the accelerator operation is performed to the high speed side even within the time (T1), the speed ratio is automatically controlled to the speed increasing side.

Further, in the speed increase control by the speed change motor (60), when detecting a vehicle speed equal to or higher than the limit value (15 km / h), the speed ratio is controlled so as to suppress the vehicle speed within the limit value. It is intended for stable running.

On the other hand, when the planting portion (15) is raised by operating the planting lever (30) from the lowered position to the neutral and raised positions, the continuously variable transmission mechanism (6) is operated by the transmission motor (60).
4) Control the speed ratio to the minimum speed and clear the timing.

In the above, the planting lever (30)
15 is operated from the neutral position to the lowered position, the solid line in FIG.
As shown in FIG. 1), the speed ratio (V) is gradually increased from the low speed to the high speed within a certain time (T1).
5 As indicated by the broken line (S3), the low speed is maintained for a certain time (K) after the operation to the descending position, and then gradually increased from the low speed to the high speed side within a certain time (T1) (intermittent increase) as described above. Alternatively, a configuration may be employed in which a slow slow-up control is performed.

As described above, the lowering of the planting portion (15) and the engaging operation of the planting clutch (72) interlock the engine speed (N) and the speed ratio (V) based on the operation of the accelerator pedal (87). The speed ratio (V) is increased by the interlocking control even during traveling while the planting section (15) is kept in the lowered state, so that the planting section (15) is in the lowered state as in the related art. Eliminating the inconvenience of keeping the speed ratio at a low speed and making the work inefficient, enabling high-speed traveling when moving in the field (idling) while keeping the planting section (15) in a lowered state,
Work efficiency when moving in the field can be improved. In addition, since the interlocking control is performed irrespective of the on / off state of the planting clutch (72) during the planting operation, a good feeling operation without a shift shock is performed during the planting operation.

In the embodiment described above, the operation of the accelerator pedal (87) and the accelerator lever (94) is detected by the accelerator sensor (91) to drive the accelerator motor (92). 87) and the accelerator lever (94) and the throttle portion (2a) may be linked and connected by an accelerator wire to directly adjust the throttle opening.

[0036]

As is apparent from the above embodiments, the present invention provides a continuously variable transmission mechanism for changing the working speed based on the engine speed (N) changed and operated by the accelerator operation members (87) and (94). In the rice transplanter in which the speed ratio of (64) is interlockingly controlled, when the planting section (15) is lowered or the planting clutch (72) is in the working condition, the engine speed (N) and the stepless speed are continuously changed. Since the interlocking control with the speed ratio of the speed change mechanism (64) is performed, when the planting section (15) is lowered and the planting clutch (72) is disengaged, when moving in the field (idle running) This allows the vehicle to run at a high speed, thereby improving work efficiency.

When the planting section (15) is lowered from the neutral position to the lowered position, a gradual speed-up control for gradually increasing the speed ratio of the continuously variable transmission mechanism (64) is performed. , A fixed time (T) after lowering the planting portion (15)
1) can be run in a low speed range to facilitate alignment before planting.

Further, when the planting section (15) is operated to descend from the neutral position to the descending position, a slow gradual acceleration control for gradually increasing the speed after maintaining the low speed for a predetermined time (K) is performed. The constant waiting time (K) after the lowering of the planting section (15) and the constant time after the waiting (T1) are run in a low-speed range, so that the setting before planting can be performed accurately. it can.

Further, an accelerator operating member (87)
(94) operation or constant rotation speed of the engine (2) (△
N) When the change is greater than or equal to the above, the slow increase control is released and the control is shifted to the interlocking control of the engine speed (N) and the speed ratio of the continuously variable transmission mechanism (64). When the setting is completed during the speed control and the engine speed (N) changes to the high-speed side due to manual accelerator operation, the speed ratio can be changed to the high-speed side to follow this, thereby improving the work efficiency. You can do it.

[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 a transmission case.

FIG. 6 is an explanatory side view of a transmission motor unit.

FIG. 7 is an explanatory diagram of a drive system of a transmission case.

FIG. 8 is an explanatory diagram of an accelerator pedal section.

FIG. 9 is a drive explanatory diagram of an accelerator unit and a continuously variable transmission mechanism.

FIG. 10 is a plan view of a driving operation unit.

FIG. 11 is an explanation of an operation lever of a mode changeover switch.

FIG. 12 is an explanatory diagram of the operation of the planting lever.

FIG. 13 is a control circuit diagram.

FIG. 14 is a flowchart.

FIG. 15 is an output diagram.

FIG. 16 is a mode diagram showing a relationship between an engine speed and a speed ratio.

[Explanation of symbols]

 (2) Engine (15) Planting part (64) Continuously variable transmission mechanism (72) Planting clutch (87) Accelerator pedal (accelerator operating member) (94) Accelerator lever (accelerator operating member) (N) Engine speed

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Toshiaki Kasahara 1-32 Chaya-cho, Kita-ku, Osaka Yanmar Agricultural Machinery Co., Ltd. F-term (reference) 2B062 AA20 AB01 AB07 BA07 BA14 BA18 BA22 BA23 BA80 CA04 CA05 CA20 CB20

Claims (4)

[Claims] In a rice transplanter in which a speed ratio of a continuously variable transmission mechanism for changing a working speed is interlocked and controlled based on an engine speed changed and operated by an accelerator operation member, a planting portion is lowered or planted. A rice transplanter characterized by performing an interlocking control of an engine speed and a speed ratio of a continuously variable transmission mechanism under a working condition in which an attached clutch is engaged. 2. A slow speed increasing control for gradually increasing the speed ratio of the continuously variable transmission mechanism when the planting section is moved down from the neutral position to the lowering position. Item 7. A rice transplanter according to item 1. 3. A slow gradual acceleration control for gradually increasing the speed after holding the low speed for a predetermined time when the planting section is lowered from the neutral position to the lowered position. 1. The rice transplanter according to 1. 4. When the accelerator operation member is operated or the engine speed is changed beyond a certain number of revolutions, the gradual increase control is released to shift to the interlocking control of the engine speed and the speed ratio of the continuously variable transmission mechanism. 4. The method according to claim 2, wherein
Rice transplanter as described.