JP2016036296A - Rice transplanter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize seedling picking operation and planting operation by a non-constant velocity transmission mechanism disposed in a planting transmission path, and meanwhile to effectively prevent or reduce a torque fluctuation caused by the non-constant velocity transmission mechanism.SOLUTION: A rice transplanter comprises a torque leveling mechanism including: an eccentric member supported relatively unrotatably by a rotary shaft forming a planting transmission path or a rotary shaft operably connected to a member forming the planting transmission path; and an elastic member operationally engaged with the eccentric member. The elastic member extends or contracts according to movement in which the eccentric member eccentrically rotates around the axis of the rotary shaft, and thus, torque for leveling a torque fluctuation caused by a non-constant velocity transmission mechanism is applied to the rotary shaft.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a rice transplanter.

  Conventionally, in a rice transplanter, an inconstant speed transmission mechanism is inserted in a planting transmission path from a driving source to a planting arm shaft that supports a rotary case, and planting is performed during one rotation of the planting arm shaft. The structure which accelerates | stimulates the angular velocity of the area which a nail | claw takes out a seedling from the seedling mat on a seedling mounting stage, and the area | region immediately after a planting nail | planting a seedling is proposed and utilized (refer following patent document 1).

  The conventional configuration increases the cutting force of the seedling mat by the planting claws and reduces the lateral movement amount of the seedling platform with respect to the seedling removing operation of the planting nails, thereby reducing the seedling mat by the planting nails. It is possible to stabilize the seedling removal operation, and in addition, the planting claw is quickly raised upward from the field after the planting operation to effectively push down the seedling on which the planting nail is planted. This is useful in that the planting operation can be stabilized.

However, on the other hand, since the angular velocity is accelerated / decelerated during one rotation of the planting arm shaft, torque fluctuation occurs in the planting transmission path.
The torque fluctuation applies a torsional mode load to the parts such as the planting vertical axis that form the planting transmission path, and causes “shaking” and “rotation unevenness” of the planting transmission path components. This may cause planting defects.

Japanese Patent Laid-Open No. 07-163216

  The present invention has been made in view of such prior art, and is a rice transplanter in which an inconstant speed transmission mechanism is inserted in a planting transmission path from a drive source to a planting arm, and the inconstant speed transmission An object of the present invention is to provide a rice transplanter that can effectively prevent or reduce torque fluctuation caused by the mechanism.

  In order to achieve the above object, the present invention is a rice transplanter in which an inconstant speed transmission mechanism is inserted in a planting transmission path from a drive source to a planting arm, and the rotation forms the planting transmission path A torque leveling mechanism including an eccentric member that is non-rotatably supported by a shaft or a rotary shaft that is operatively connected to a member that forms the planting transmission path, and an elastic member that is operatively engaged with the eccentric member And the elastic member expands and contracts in response to the eccentric rotation of the eccentric member around the axis of the rotary shaft, and generates torque that equalizes torque fluctuations caused by the inconstant speed transmission mechanism. A rice transplanter to be added to is provided.

Preferably, the rotation shaft is operatively connected to the planting arm so as to rotate twice according to one rotation of the planting arm.
In this case, the eccentric member has a circular shape whose diameter is larger than that of the rotating shaft and whose center is eccentric with respect to the axis of the rotating shaft, the elastic member is a coil spring, and the torque leveling mechanism includes: Furthermore, an engagement member is provided that includes a cylindrical portion that is extrapolated to the eccentric member so as to be relatively rotatable, and an engagement piece that is provided on the cylindrical portion.

  The coil spring is disposed so as to be substantially orthogonal to the rotation shaft, the first end portion on the side separated from the rotation shaft is a fixed end, and the second end portion on the side opposite to the first end portion is The engaging member is connected to the engaging piece.

  More preferably, the eccentric member is supported by the rotating shaft so that the position around the axis of the rotating shaft can be adjusted.

The planting transmission path includes a planting horizontal axis along the vehicle width direction, a planting vertical axis along the vehicle longitudinal direction with the front end portion being operatively connected to the planting horizontal axis, and a vehicle width direction. And a planting arm shaft operatively connected to a rear end of the planting longitudinal axis.
In this case, preferably, the eccentric member is supported by the planting vertical axis so that the planting vertical axis acts as the rotation axis.

  In the configuration in which the eccentric member is supported by the planting longitudinal axis, preferably, a bulging portion integrally formed with the tubular portion in a planting bevel case having a tubular portion that accommodates the planting longitudinal axis. Is provided.

  The bulging portion has an eccentric rotation space that allows the eccentric member to rotate eccentrically around the axis of the planting vertical axis, and a spring installation space that extends upward from the eccentric rotation space.

  According to the rice transplanter according to the present invention, relative rotation to a rotary shaft that forms a planting transmission path in which an inconstant speed transmission mechanism is inserted or a rotary shaft that is operatively connected to a member that forms the planting transmission path. A torque leveling mechanism including an eccentric member that is impossiblely supported and an elastic member that is operatively engaged with the eccentric member, wherein the eccentric member is eccentric about an axis of the rotation shaft; Since it is configured to add torque to the rotating shaft that expands and contracts in accordance with the rotating motion and leveles the torque fluctuation caused by the inconstant speed transmission mechanism, stabilizing the seedling removing operation of the planting claw In addition, torque fluctuation caused by the non-uniform speed transmission mechanism can be effectively prevented or reduced while obtaining the effect of the non-constant speed transmission mechanism of stabilizing the planting operation.

FIG. 1 is a side view of a rice transplanter according to an embodiment of the present invention. FIG. 2 is a transmission schematic diagram of a planting unit in the rice transplanter. FIG. 3 is a partial vertical perspective view of the planting unit. FIG. 4 is a perspective view of the planting unit. FIGS. 5A to 5D are schematic views of a torque leveling mechanism provided in the rice transplanter, and the torque leveling mechanism every time the planting vertical axis of the planting unit rotates 1/4. The operating state of is shown. FIG. 6 is a graph showing changes in torque generated by the inconstant speed transmission mechanism provided in the rice transplanter and leveling torque generated by the torque leveling mechanism.

Hereinafter, preferred embodiments of a rice transplanter according to the present invention will be described with reference to the accompanying drawings.
In FIG. 1, the side view of the rice transplanter 1 which concerns on this Embodiment is shown.

  As shown in FIG. 1, the rice transplanter 1 includes a traveling machine 10 and a planting device 50 connected to a rear portion of the traveling machine 10 so as to be movable up and down.

  The traveling machine 10 includes a vehicle body frame 11, an engine 12, a traveling transmission (not shown) that changes the rotational power from the engine 12, and front wheels 15F and rear wheels 15R. Of the front wheels 15F and the rear wheels 15R, the wheels that act as drive wheels are driven by the rotational power operatively transmitted from.

  In the present embodiment, the rear wheel 15R is a main drive wheel and the front wheel 15F is a sub drive wheel, and rotational power is transmitted from the traveling transmission to both the front wheel 15F and the rear wheel 15R. It has come to be.

  The planting device 50 includes a planting center case 51 (see FIG. 2 below) that operatively inputs rotational power from the engine 12, and a machine body that operatively inputs rotational power from the planting center case 51. A plurality of planting units 100 arranged in parallel in the width direction, a seedling mounting base 52 that supports a seedling mat and is reciprocated in the body width direction by rotational power operatively transmitted from the engine 12, and a plurality The float 53 is included.

In FIG. 2, the transmission schematic diagram of the said planting unit 100 is shown.
As shown in FIG. 2, rotational power that is branched from the traveling transmission and is operatively transmitted via the inter-strain transmission 18 is input to the planting center case 51.

  The planting unit 100 receives rotational power from the planting center case 51 via the planting horizontal shaft 55.

  Specifically, as shown in FIG. 2, the planting unit 100 includes a planting longitudinal axis 120, an upstream bevel gear mechanism 110, a planting bevel case 130, a downstream bevel gear mechanism 140, a planting arm shaft 150, a pair of left and right A rotary case 160, a pair of planting claw shafts 170 supported by each of the pair of rotary cases 160, a rotary arm shaft 180 extrapolated to the planting claw shafts 170, and a planetary gear housed in the rotary case 160 There are a mechanism 190, a planting arm 200 connected to the rotary arm shaft 180 so as not to rotate relative to the rotary arm shaft 180, and a planting claw 210 supported by the planting arm 200 so as to be reciprocally movable.

  The planting vertical axis 120 extends in the longitudinal direction of the machine body in a state where rotational power can be operatively input from the planting horizontal axis 55.

  The upstream bevel gear mechanism 110 is configured to transmit the rotational power of the planting horizontal shaft 55 to the front end portion of the planting vertical shaft 120.

  Specifically, as shown in FIG. 2, the upstream bevel gear mechanism 110 is engaged with the first bevel gear 111 supported by the planting horizontal shaft 55 so as not to rotate relative to the first bevel gear 111. And a second bevel gear 112 supported directly or indirectly on the front end of the planting longitudinal axis 120.

In the present embodiment, as shown in FIG. 2, the second bevel gear 112 is supported on the planting longitudinal axis 120 via a torque limiter 115.
That is, as shown in FIG. 2, in the present embodiment, the torque limiter 115 is provided between the upstream bevel mechanism 110 and the planting longitudinal axis 120 in the transmission direction, and the planting longitudinal axis When a load exceeding a predetermined value is applied to 120, power transmission from the planting horizontal axis 55 to the planting vertical axis 120 is cut off.

  As shown in FIG. 2, the planting bevel case 130 includes an upstream part 131 that houses the upstream bevel gear mechanism 110, a cylindrical part 132 that houses the planting longitudinal axis 120, and the downstream bevel gear mechanism. And a downstream portion 133 that accommodates 140.

  The planting arm shaft 150 is supported on the rear end side of the planting bevel case 130 so as to be rotatable about its axis along the width direction of the machine body and with both ends extending outward from the planting bevel case 130. Rotational power is operatively input from the planting longitudinal axis 120 via the downstream bevel gear mechanism 140.

  The downstream bevel gear mechanism 140 transmits the rotational power of the planting longitudinal axis 120 to the planting arm shaft 150 directly or indirectly.

  Specifically, the downstream bevel gear mechanism 140 is directly engaged with the planting arm shaft 150 in a state of being engaged with the first bevel gear 141 supported by the planting longitudinal axis 120 so as not to be relatively rotatable and the first bevel gear 141. Or it has the 2nd bevel gear 142 supported indirectly.

  In the present embodiment, the second bevel gear 142 is supported by the planting arm shaft 150 via a unit clutch 145.

  That is, as shown in FIG. 2, in the present embodiment, the unit clutch 145 is provided between the downstream bevel mechanism 140 and the planting arm shaft 150 in the transmission direction. The power transmission from the planting vertical axis 120 to the planting arm shaft 150 is engaged and disengaged.

  The pair of left and right rotary cases 160 are connected to both end portions of the planting arm shaft 150 extending outward from the planting bevel case 130 so as not to rotate relative to each other.

  The pair of planting claw shafts 170 along the body width direction at positions spaced apart from each other by an equal distance from the axis line of the planting arm shaft 150 serving as the rotation center of the rotary case 160 to the outside in the radial direction. In this state, the rotary case 160 is supported so as to be rotatable around the axis.

  The rotary arm shaft 180 is extrapolated to the planting claw shaft 170 so as to be relatively rotatable.

  The planetary gear mechanism 190 is connected to a sun gear 191 that cannot rotate relative to the planting bevel case 130, and is connected to the sun gear 191 via an intermediate gear 192 and supported by the rotary arm shaft 180. And a planetary gear 193.

  The planting arm 200 is connected to the rotary arm shaft 180 so as not to be relatively rotatable.

  The planting claw 210 is supported by the planting arm 200 in a state where the planting claw 210 reciprocates along the axial direction by power transmitted from the planting claw shaft 170 via the cam mechanism 205.

  In the rice transplanter 1, an inconstant speed transmission mechanism is inserted in a planting transmission path from the engine 12 to the planting arm 200, and the planting arm 200 is configured to rotate at an infinite speed. ing.

  The inconstant speed transmission mechanism includes a section in which the planting claws 210 take out seedlings from a seedling mat on the seedling platform 52 while the planting arm 200 makes one rotation, and the planting claws 210 are in a field. The angular velocity of the planting arm shaft 150 in the section immediately after planting seedlings is increased as compared with other sections, and thereby, the seedling removing operation by the planting claws 210 and the planting claws 210 are increased. It is possible to stabilize the planting operation.

  In the present embodiment, an inconstant speed mechanism (not shown) and the downstream bevel gear mechanism 140 provided in the inter-strain transmission 18 are configured to act as the inconstant speed transmission mechanism.

  Specifically, the first and second bevel gears 141 and 142 of the downstream bevel gear mechanism 140 are arranged so that the planting claw 210 is moved from the seedling mat on the seedling platform 52 while the planting arm 200 rotates once. A non-constant speed bevel gear configured to increase the angular velocity of the planting arm 200 in the section for taking out the seedling and the section immediately after the planting claw 210 has planted the seedling in the field compared to the other sections; Has been.

  Note that the non-constant speed mechanism provided in the inter-stock transmission 18 is configured to synchronize with the downstream bevel gear mechanism 140.

  As described above, by providing the unequal speed transmission mechanism in the planting transmission path, it is possible to stabilize the seedling harvesting operation and the planting operation. During rotation, acceleration / deceleration of the angular velocity occurs, and torque fluctuation occurs in the planting transmission path.

  The torque fluctuation applies a torsional mode load to all parts such as the planting vertical axis 120 that form the planting transmission path, and the torsional vibration and inequality of the planting transmission path components. There is a risk of causing a planting failure due to a “shift in the timing of the fast rotation”.

  In this regard, the rice transplanter 1 according to the present embodiment includes a torque leveling mechanism 300 that leveles the torque fluctuation caused by the non-uniform speed transmission mechanism, thereby causing the torque fluctuation due to the torque fluctuation. The inconvenience is prevented or reduced.

  Specifically, as shown in FIG. 2, the torque leveling mechanism 300 is relatively non-rotatable to a rotary shaft that forms the planting transmission path or a rotary shaft that is operatively connected to a member that forms the planting transmission path. The eccentric member 310 is supported, and the elastic member 320 is operatively engaged with the eccentric member 310, and the elastic member 310 responds to the eccentric rotation of the eccentric member 310 about the axis of the rotation shaft. 320 is configured to expand and contract, and to apply a leveling torque for leveling torque fluctuations caused by the non-uniform speed transmission mechanism to the rotating shaft.

  Preferably, a speed reduction mechanism is provided between the rotating shaft and the planting arm 200 with respect to the transmission direction so that the planting arm 200 makes one rotation in response to a gear ratio of 1/2, that is, two rotations of the rotating shaft. it can.

  By providing such a speed reduction mechanism and rotating the rotating shaft at a rotational speed twice that of the planting arm 200, the leveling torque by the torque leveling mechanism 300 is applied to the rotating shaft. With this configuration, leveling torque can be applied to the rotating shaft in a timely manner with respect to torque fluctuations caused by the inconstant speed transmission mechanism.

  That is, as described above, the inconstant speed transmission mechanism includes the section where the planting claw 210 takes out the seedling from the seedling mat on the seedling platform 52, and the planting claw 510 immediately after planting the seedling in the field. The angular velocity of the planting arm shaft 150 in this section is increased as compared with other sections.

That is, the inconstant speed transmission mechanism is configured such that, during one rotation of the planting arm 200, the first angular velocity low speed section and the first angular speed high speed section (the planting claw 210 is transferred from the seedling mat on the seedling platform 52 to the seedling ), A second angular speed low speed section, and a second angular speed high speed section (a section immediately after the planting claws 510 plant seedlings in the field).
In other words, the periods of the angular velocity low speed section and the angular speed high speed section substantially coincide with the timing at which the planting arm 200 makes a 1/2 rotation.

  Here, as described above, if the speed reduction mechanism having a gear ratio of 1/2 is provided between the rotating shaft and the planting arm 200 in the transmission direction, when the planting arm 200 rotates 1/2 times, That is, the rotation shaft is rotated once. Therefore, the periods of the angular velocity low speed section and the angular velocity high speed section substantially coincide with the timing at which the rotating shaft makes one rotation.

  Therefore, if the speed reduction mechanism is provided, a leveling torque for leveling the torque fluctuation caused by the increase / decrease in the angular velocity can be added to the rotating shaft in a timely manner using a coil spring having a simple structure.

In the present embodiment, the downstream bevel gear mechanism 140 is also configured to act as the speed reduction mechanism.
That is, the gear ratios of the first and second bevel gears 141 and 142 of the downstream bevel gear mechanism 140 are set so that the transmission gear ratio becomes 1/2.

  In addition, in the present embodiment, the leveling torque is applied to the planting vertical axis 120 located upstream of the bell gear mechanism 140 toward the downstream side, which also functions as the speed reduction mechanism. Yes.

FIG. 3 shows a partial vertical perspective view of the planting unit 100.
FIG. 4 shows a perspective view of the planting unit 100.

  As shown in FIGS. 2 and 3, in the present embodiment, the eccentric member 310 has a diameter larger than the planting longitudinal axis 120 that acts as the rotation axis and the axis of the planting longitudinal axis 120 at the center. The elastic member 320 is a coil spring.

The coil spring 320 is operatively connected to the eccentric member 310 through an engaging member 330.
Specifically, in the present embodiment, as shown in FIGS. 2 and 3, the torque leveling mechanism 300 further includes the engagement member 330 inserted between the eccentric member 310 and the coil spring 320. Have.

  The engaging member 330 includes a cylindrical portion 331 that is extrapolated relative to the eccentric member 310 and an engaging piece 332 that is provided on the cylindrical portion 331 and to which an end of the coil spring 320 can be connected. have.

  As shown in FIG. 3, the coil spring 320 is arranged so as to be substantially orthogonal to the planting longitudinal axis 120 that acts as the rotation axis, and the first end on the side separated from the planting longitudinal axis 120. The portion 321 is a fixed end, and the second end 322 opposite to the first end 321 is connected to the engagement piece 332 of the engagement member 330.

  In the present embodiment, as shown in FIGS. 3 and 4, the planting bevel case 130 includes the cylindrical portion in addition to the upstream portion 131, the cylindrical portion 132, and the downstream portion 133. 132 has a bulging portion 135 integrally formed with 132.

As shown in FIG. 3, the bulging portion 135 includes an eccentric rotation space 135a that allows the eccentric member 310 to rotate eccentrically around the axis of the planting longitudinal axis 120, and the planting from the eccentric rotation space 135a. A spring installation space 135b extending upward based on the installation state of the unit 100.
In this case, the first end 321 of the coil spring 320 is fixedly connected to the radially outward side (upper end side) of the bulging portion 135.

  An opening (not shown) for attaching and detaching the coil spring 320 is formed on one side surface of the bulging portion 135, and the opening is closed by a detachable lid member 136 (see FIG. 4). Yes.

  FIGS. 5A to 5D are schematic views of the torque leveling mechanism 300 acting on the planting longitudinal axis 120, and the torque leveling when the planting longitudinal axis 120 makes one rotation around the axis. The operating state of the conversion mechanism 300 is shown in time series.

  Specifically, FIG. 5A shows a state where the coil spring 320 is shortest (or not stretched) (the second end 322 is closest to the first end 321 (FIG. 5 (a)). From the state shown in d))), the planting vertical axis 120 is shown in a state of a quarter turn.

FIG.5 (b) has shown the state which the said planting vertical axis | shaft 120 further rotated 1/4 from the state shown to Fig.5 (a).
In the state shown in FIG. 5 (b), the coil spring 320 is most extended (the second end 322 is most separated from the first end 321).

  FIG.5 (c) has shown the state which the said planting vertical axis | shaft 120 further rotated 1/4 from the state shown in FIG.5 (b).

  FIG.5 (d) has shown the state which the said planting vertical axis | shaft 120 further rotated 1/4 from the state shown in FIG.5 (c). The state shown in FIG. 5 (d) is the state where the coil spring 320 is the shortest as described above, and when the planting vertical axis 120 is further rotated 1/4 from this state, the state shown in FIG. 5 (a) is obtained. Return to.

  Here, the section in which the second end 322 of the coil spring 320 moves away from the first end 321 while the planting longitudinal axis 120 makes one rotation around the axis (FIG. 5 (d) → 5 (a) → FIG. 5 (b)), the planting vertical axis 120 rotates against the elastic force of the coil spring 320.

In this section, the coil spring 320 applies a torque that faces in a direction opposite to the rotation direction of the planting longitudinal axis 120.
That is, in this section, the torque leveling mechanism 300 applies a deceleration-side torque to the planting vertical axis 120 that functions as the rotation axis.

  On the other hand, the section in which the second end 322 of the coil spring 320 moves close to the first end 321 while the planting longitudinal axis 120 makes one rotation around the axis (FIG. 5B → FIG. 5 (c) → section 5 (d)), the planting vertical axis 120 rotates while receiving a biasing force from the coil spring 320.

In this section, the coil spring 320 applies a torque that points in the same direction as the rotation direction of the planting longitudinal axis 120.
That is, in this section, the torque leveling mechanism 300 applies acceleration-side torque to the planting vertical axis 120 that functions as the rotation axis.

  In FIG. 6, the torque generated by the inconstant speed transmission mechanism and the leveling torque generated by the torque leveling mechanism 300 are determined according to the rotation angle of the planting arm 200 (the planting longitudinal axis 120). The graph showing how it changes is shown.

  As described above, the unequal speed transmission mechanism generates an angular velocity low speed section and an angular speed high speed section during one rotation of the rotating shaft (the planting longitudinal axis 120 in the present embodiment).

  As shown in FIG. 6, when the torque generated on the rotary shaft is the vertical axis and the rotation angle of the rotary shaft is the horizontal axis, the torque applied to the rotary shaft by the inconstant speed transmission mechanism is It fluctuates along a periodic function represented by a substantially sinusoidal curve having a period of one rotation of the rotation axis as one period.

  On the other hand, as described above, the leveling torque applied to the rotating shaft by the torque leveling mechanism 300 is also the case where the torque applied to the rotating shaft is the vertical axis and the rotational angle of the rotating shaft is the horizontal axis. , And fluctuates along a periodic function represented by a substantially sinusoidal curve having a period of one rotation of the rotating shaft as one period.

  Therefore, by configuring the torque leveling mechanism 300 such that the direction of the leveling torque generated by the torque leveling mechanism 300 is opposite to the direction of the torque generated by the non-uniform speed transmission mechanism, FIG. As shown in FIG. 4, torque fluctuations caused by the inconstant speed transmission mechanism can be effectively prevented or reduced.

  In the example shown in FIG. 6, the periodic function of the torque added by the torque leveling mechanism 300 is configured to have an opposite phase with respect to the periodic function of the torque generated by the unequal speed transmission mechanism. However, the present invention is not limited to such a form.

  That is, as long as the torque generated by the unequal speed transmission mechanism can be effectively suppressed, the periodic function of the leveling torque is shifted with respect to the periodic function of the torque generated by the unequal speed transmission mechanism in a range that is not in the opposite phase. Is also possible.

Preferably, the eccentric member 310 can be fixed to the rotating shaft so that the position of the eccentric member 310 can be adjusted around the axis of the rotating shaft.
According to such a configuration, it is possible to easily adjust the phase of the periodic function of the leveling torque with respect to the periodic function of the torque generated by the inconstant speed transmission mechanism, and a desired leveling torque can be obtained.

1 Rice transplanter 12 Engine (drive source)
55 Planting horizontal axis 120 Planting vertical axis (rotating axis)
130 Planting bevel case 132 Tubular portion 135 Swelling portion 135a Eccentric rotation space 135b Spring installation space 150 Planting arm shaft 160 Rotary case 140 Downstream bevel gear mechanism (non-constant speed transmission mechanism)
300 Torque leveling mechanism 310 Eccentric member 320 Coil spring (elastic member)
321 1st end 322 2nd end 330 Engagement member 331 Tube part 332 Engagement piece

Claims (5)

A rice transplanter in which an inconstant speed transmission mechanism is inserted in a planting transmission path from a driving source to a planting arm,
An eccentric member that is supported so as not to rotate relative to a rotary shaft that forms the planting transmission path or a rotary shaft that is operatively connected to a member that forms the planting transmission path, and is operatively engaged with the eccentric member A torque leveling mechanism including an elastic member, and the elastic member expands and contracts in response to the eccentric rotation of the eccentric member about the axis of the rotation shaft, and torque fluctuation caused by the inconstant speed transmission mechanism A rice transplanter characterized in that a torque for leveling is applied to the rotating shaft. The rotating shaft is operatively connected to the planting arm so as to rotate twice according to one rotation of the planting arm,
The eccentric member has a circular shape having a diameter larger than that of the rotating shaft and a center eccentric with respect to the axis of the rotating shaft;
The elastic member is a coil spring,
The torque leveling mechanism further includes an engagement member including a cylindrical portion extrapolated to the eccentric member so as to be relatively rotatable and an engagement piece provided on the cylindrical portion,
The coil spring is disposed so as to be substantially orthogonal to the rotation shaft, the first end portion on the side separated from the rotation shaft is a fixed end, and the second end portion on the side opposite to the first end portion is The rice transplanter according to claim 1, wherein the rice transplanter is connected to the engagement piece of the engagement member.   3. The rice transplanter according to claim 2, wherein the eccentric member is supported by the rotary shaft so that the position around the axis of the rotary shaft can be adjusted. The planting transmission path includes a planting horizontal axis along the vehicle width direction, a planting vertical axis along the vehicle longitudinal direction with the front end portion being operatively connected to the planting horizontal axis, and a vehicle width direction. A planting arm shaft operatively coupled along and along the rear end of the planting longitudinal axis,
The rice transplanter according to claim 2 or 3, wherein the eccentric member is supported by the planting vertical axis so that the planting vertical axis acts as the rotation axis. The planting bevel case having a cylindrical portion that accommodates the planting longitudinal axis is provided with a bulging portion that is integrally formed with the cylindrical portion,
The bulging portion has an eccentric rotation space that allows the eccentric member to rotate eccentrically about the axis of the planting vertical axis, and a spring installation space that extends upward from the eccentric rotation space. The rice transplanter according to claim 4.