JP6120635B2 - Rice transplanter - Google Patents

Description

  The present invention relates to a rice transplanter that has a seedling stage and a plurality of planting claws and performs seedling planting work continuously.

  In general, a rice transplanter includes a ground leveling device for scribing in front of a seedling planting device having a seedling stand, a planting claw, and the like, and planting seedlings while leveling the rice field. In this type of rice transplanter, for example, a leveling drive shaft is connected to an input shaft of a rear axle case that transmits power from an engine via a gear or the like, and the leveling device is driven via the leveling drive shaft. . A connecting gear or the like for connecting the leveling drive shaft to the input shaft of the rear axle case is disposed, for example, in a power take-out case provided on the front side of the rear axle case (see Patent Documents 1 and 2).

JP 2004-113185 A JP 2007-252228 A

  The power take-out case described above is separate from the rear axle case, and includes a power transmission system such as a connecting gear and a transmission shaft. The power take-out case is attached to the rear axle case via a spacer. The transmission shaft of the power take-out case is connected to the input shaft of the rear axle case via a joint member. Therefore, in the configuration using the power take-out case, there is a problem that the number of parts increases and the rice transplanter increases in weight and costs. Also, if the leveling device receives a large resistance from muddy water or mud or bites foreign matter, an overload will be applied to the leveling drive shaft, so a structure to prevent the leveling drive shaft from being damaged by such overload should be provided. However, the increase in weight and cost of Sarada transplanter will be a problem.

  In this respect, if a connecting gear or the like is arranged in the rear axle case, the power take-out case can be omitted, which is preferable. However, when connecting gears and the like are arranged in the rear axle case, it is necessary to project the front end side and the rear end side of the leveling drive shaft before and after the rear axle case, and the shaft hole that supports the leveling drive shaft is provided in the rear axle case. Will open before and after. Then, when it is desired to eliminate the leveling device and remove the leveling drive shaft, there is a problem that the seal structure for closing the front and rear openings of the shaft hole that supports the leveling drive shaft is complicated. Also, there is a problem that the assembly of the leveling drive shaft becomes complicated because the assembly of the bearing to the leveling drive shaft must be performed from both the front end side and the rear end side of the leveling drive shaft. Furthermore, there is room for consideration as to how to provide a structure that prevents damage to the leveling drive shaft due to overload in association with the leveling drive shaft.

  This invention makes it the technical subject to provide the rice transplanter which solved said problem.

The invention of claim 1 includes a traveling machine body equipped with an engine, a seedling planting device mounted on a rear end side of the traveling machine body, a rear axle case supporting left and right rear wheels, and a leveling device for leveling the planted rice field. In the rice transplanter, the rear axle case includes a rear input shaft to which the power of the engine is transmitted, and a leveling drive shaft that branches the power of the rear input shaft and transmits it to the leveling device. The rear input shaft and the front side of the leveling drive shaft are positioned so as to overlap with each other when viewed in the radial direction of the rear input shaft, and the longitudinal axis of the leveling drive shaft is arranged at the rear end side of the rear input shaft. The rear axle case is formed in the rear axle case so as to open toward the rear side of the rear axle case, and is connected to the front side of the leveling drive shaft. The above Ground leveling clutch Tsugidan the power transmission from the input shaft is provided, wherein the rear side of the leveling drive shaft is provided with a torque limit data that can limit the power transmission to the ground leveling drive shaft, transmitted to the rear input shaft power Is transmitted from the torque limiter through the leveling clutch to the leveling drive shaft, and the leveling drive shaft is extracted together with the leveling clutch and the torque limiter behind the rear axle case from the rearward shaft hole. As possible, the size of the opening of the rearward shaft hole is set larger than that of the leveling clutch and the torque limiter.

According to the present invention, it comprises a traveling machine body equipped with an engine, a seedling planting device mounted on the rear end side of the traveling machine body, a rear axle case for supporting left and right rear wheels, and a leveling device for leveling the planted rice field. in it are rice transplanter, wherein the internal rear axle case includes a rear input shaft to which power of the engine is transmitted, and a ground leveling drive shaft which branches the power of the rear input shaft is transmitted to the ground leveling device, wherein When viewed in the radial direction of the rear input shaft, the rear input shaft and the front side of the leveling drive shaft are positioned so as to overlap with each other, and a longitudinal midway portion of the leveling drive shaft is disposed on the rear end side of the rear input shaft. A rearward shaft hole that is coupled so as to be able to transmit power and that houses the leveling drive shaft is formed in the rear axle case so as to open toward the rear surface side of the rear axle case, and on the front side of the leveling drive shaft, Said Ground leveling clutch Tsugidan the power transmission from the input shaft is provided, wherein the rear side of the leveling drive shaft is provided with a torque limit data that can limit the power transmission to the ground leveling drive shaft, transmitted to the rear input shaft power Is transmitted from the torque limiter through the leveling clutch to the leveling drive shaft, and the leveling drive shaft is extracted together with the leveling clutch and the torque limiter behind the rear axle case from the rearward shaft hole. Since the size of the opening of the rearward shaft hole is set to be larger than that of the leveling clutch and the torque limiter, for example, the soil level of the field is hard and the leveling device receives great resistance from muddy water and mud. When a foreign object is caught, an overload applied to the leveling drive shaft can be easily released by the torque limiter. Therefore, it is possible to prevent problems due to excessive driving of the leveling device, for example, damage to the driving system such as the leveling drive shaft and the leveling device itself. There is also an advantage that the torque limiter can be compactly assembled in the rear axle case by using the leveling drive shaft that transmits power to the leveling device.

  Further, not only the torque limiter but also the leveling clutch can be compactly assembled in the rear axle case by using the leveling drive shaft that transmits power to the leveling device. In addition, the space for arranging the leveling drive shaft, the torque limiter, and the leveling clutch can be easily secured inside the rear axle case.

  Further, a rearward shaft hole that houses the leveling drive shaft is formed in the rear axle case so as to open toward the rear surface side of the rear axle case, and the leveling clutch and the rear axle case are rearward from the rearward shaft hole. Since the leveling drive shaft can be extracted together with the torque limiter, the combination of the leveling drive shaft, the torque limiter and the leveling clutch can be easily attached to and detached from the rear axle case. For this reason, it is possible to easily cope with specifications with or without a leveling device. In addition, one type of rear axle case can be shared by two specifications with or without a leveling device, and the manufacturing cost can be reduced as a whole model.

It is a left view of the riding type rice transplanter in the embodiment. It is a top view of a riding type rice transplanter. It is a left view which shows the positional relationship of an engine, a transmission case, and a rear axle case. It is a top view which shows the positional relationship of an engine, a transmission case, and a rear axle case. It is a top view of the driving operation part which abbreviate | omitted the steering handle. It is a drive system figure of a riding type rice transplanter. It is a hydraulic circuit diagram of a riding type rice transplanter. It is sectional drawing of a planetary gear apparatus. It is a side view of a seedling planting device and a leveling device. It is a top sectional view of a rear axle case. It is side surface sectional drawing of a rear axle case. It is side surface sectional drawing explaining the taking-out aspect of the leveling drive shaft. It is a plane sectional view of a leveling drive shaft. It is a back surface explanatory view inside a rear axle case.

  Hereinafter, an embodiment embodying the present invention will be described with reference to the drawings in a case where the invention is applied to an eight-planted riding rice transplanter 1 (hereinafter simply referred to as a rice transplanter 1). In the following description, the left side in the traveling direction of the traveling machine body 2 is simply referred to as the left side, and the right side in the traveling direction is also simply referred to as the right side.

  First, the outline | summary of the rice transplanter 1 is demonstrated, referring FIGS. The rice transplanter 1 according to the embodiment includes a traveling machine body 2 supported by a pair of left and right front wheels 3 and a pair of left and right rear wheels 4 as a traveling unit. An engine 5 is mounted on the front portion of the traveling machine body 2. Power from the engine 5 is transmitted to the rear transmission case 6 to drive the front wheels 3 and the rear wheels 4 so that the traveling machine body 2 travels forward and backward. A front axle case 7 projects from the left and right sides of the transmission case 6, and the front wheels 3 are attached to a front axle 36 extending from the front axle case 7 to the left and right so as to be steerable. A cylindrical frame 8 protrudes behind the transmission case 6, a rear axle case 9 is fixed to the rear end side of the cylindrical frame 8, and the rear wheel 4 is attached to a rear axle 37 that extends outward from the rear axle case 9 to the left and right. ing.

  As shown in FIGS. 1 and 2, an operator boarding work step (vehicle body cover) 10 is provided on the upper surface side of the front part and the center part of the traveling machine body 2. A front bonnet 11 is disposed above the front part of the work step 10, and the engine 5 is installed inside the front bonnet 11. A traveling speed change pedal 12 for stepping operation is disposed on the upper side of the work step 10 on the rear side of the front bonnet 11. Although details are omitted, the rice transplanter 1 according to the embodiment adjusts the shift power output from the hydraulic continuously variable transmission 40 of the transmission case 6 by driving the variable speed electric motor according to the depression amount of the travel shift pedal 12. Is configured to do.

  Further, the driving operation unit 13 on the rear upper surface side of the front bonnet 11 is provided with a steering handle 14, a traveling main transmission lever 15, and a work lever 16 as a lifting operation tool (see FIG. 5). A steering seat 18 is disposed via a seat frame 17 behind the front bonnet 11 on the upper surface of the work step 10. Note that left and right spare seedling platforms 24 are provided on the left and right sides of the front bonnet 11 with the operation step 10 interposed therebetween.

  A link frame 19 is erected at the rear end of the traveling machine body 2. An eight-row seedling planting device 23 is connected to the link frame 19 via an elevating link mechanism 22 including a lower link 20 and a top link 21 so as to be elevable. In this case, a hitch bracket 38 is provided on the front side of the seedling planting device 23 via a rolling fulcrum shaft (not shown). By connecting a hitch bracket 38 to the rear side of the lifting link mechanism 22, the seedling planting device 23 is disposed behind the traveling machine body 2 so as to be movable up and down. The cylinder base end side of the hydraulic lift cylinder 39 is supported on the rear upper surface of the cylindrical frame 8 so as to be vertically rotatable. The rod tip side of the lifting cylinder 39 is connected to the lower link 20. As a result of vertically moving the lifting link mechanism 22 by the expansion and contraction of the lifting cylinder 39, the seedling planting device 23 moves up and down. Note that the seedling planting device 23 is configured to be rotatable about the rolling fulcrum axis so as to be able to change the inclined posture in the left-right direction.

  The operator gets on the work step 10 from the boarding / alighting step 25 on the side of the work step 10 and drives the seedling planting device 23 to move the seedling planting device 23 and move the seedling planting in the field while moving in the field by the driving operation. Perform work (rice planting work). During the seedling planting operation, the operator replenishes the seedling planting device 23 with a seedling mat on the preliminary seedling mounting table 24 as needed.

  As shown in FIGS. 1 and 2, the seedling planting device 23 includes a planting input case 26 to which power is transmitted from the engine 5 via the mission case 6, and four sets of eight strips connected to the planting input case 26. Planting transmission case 27 (one set in Nijo), seedling planting mechanism 28 provided on the rear end side of each planting transmission case 27, seedling mount 29 for eight-row planting, and each planting transmission case 27 And a float 32 for uniforming the surface of the surface. The seedling planting mechanism 28 is provided with a rotary case 31 having two planting claws 30 for one line. Two rotary cases 31 are arranged in the planting transmission case 27. By one rotation of the rotary case 31, the two planting claws 30 cut out and grasp one seedling each, and plant it on the field leveled by the float 32. On the front side of the seedling planting device 23, a leveling rotor 85 as a leveling device for leveling (leveling) the farm scene is provided so as to be movable up and down.

  Although details will be described later, the power from the engine 5 via the transmission case 6 is transmitted not only to the front wheels 3 and the rear wheels 4, but also to the planting input case 26 of the seedling planting device 23. In this case, the power from the transmission case 6 toward the seedling planting device 23 is once transmitted to the inter-plant transmission case 75 provided on the upper right side of the rear axle case 9, and is transmitted from the inter-plant transmission case 75 to the planting input case 26. The The seedling planting mechanism 28 and the seedling mount 29 are driven by the transmitted power. The inter-strain shifting case 75 includes an inter-strain shifting mechanism 76 that switches between planted seedlings to, for example, sparse planting, standard planting, or dense planting, and a planting clutch 77 that interrupts power transmission to the planting planting device 23. (See FIG. 6).

  A side marker 33 is provided on the left and right outside of the seedling planting device 23. The side marker 33 includes a marker ring body 34 for muscle pulling and a marker arm 35 that pivotally supports the marker ring body 34 so as to be rotatable. The base end side of each marker arm 35 is pivotally supported on the left and right outer sides of the seedling planting device 23 so as to be rotatable left and right. The side marker 33 is moved away from the surface by raising the marker wheel body 34 based on the operation posture of the operation lever 16 in the driving operation unit 13 and forming a trajectory as a reference in the next process by landing on the surface. The non-working posture is configured to be rotatable.

  As shown in FIGS. 3 and 4, the traveling machine body 2 includes a pair of left and right machine body frames 50 extending in the front-rear direction. Each body frame 50 is divided into a front frame 51 and a rear frame 52. The rear end portion of the front frame 51 and the front end portion of the rear frame 52 are welded and fixed to a laterally long intermediate connection frame 53. The front ends of the pair of left and right front frames 51 are fixed to the front frame 54 by welding. The rear end sides of the left and right rear frames 52 are fixed to the rear frame 55 by welding. The front frame 54, the left and right front frames 51, and the intermediate connection frame 53 are configured in a square frame shape in plan view. Similarly, the intermediate connection frame 53, the left and right rear frames 52, and the rear frame 55 are also configured in a square frame shape in plan view.

  As shown in FIG. 4, the front portions of the left and right front frames 51 are connected by two front and rear base frames 56. An intermediate portion of each base frame 56 is formed in a shape bent into a U shape so as to be positioned lower than the left and right front frames 51. The left and right end portions of each base frame 56 are fixed to the corresponding front frame 51 by welding. The engine 5 is mounted on and supported by the front and rear base frames 56 via a substantially flat engine stand 57 and a plurality of vibration isolating rubbers (not shown). The rear base frame 56 is connected to the front portion of the transmission case 6 via the rear relay bracket 60.

  As can be seen from FIG. 4, the rear portions of the left and right front frames 51 are connected to a front axle case 7 projecting from the left and right sides of the mission case 6. The left and right ends of a U-shaped frame 61 extending rearward and obliquely downward in a side view are welded and fixed to the center side of the intermediate connection frame 53. The middle part of the U-shaped frame 61 is connected to the middle part of the cylindrical frame 8 that connects the transmission case 6 and the rear axle case 9 (see FIGS. 3 and 4). The upper end sides of the left and right vertical frames 62 are welded and fixed to the middle portion of the rear frame 55. An intermediate portion of a laterally long rear axle support frame 63 is fixed by welding to the lower ends of the left and right vertical frames 62. The left and right ends of the rear axle support case 63 are connected to the rear axle case 9. A muffler 65 for reducing the exhaust noise of the engine 5 is disposed below the step support base 64 projecting outward from the left front frame 51.

  As shown in FIGS. 3 and 4, a power steering unit 66 is provided at the front portion of the transmission case 6 disposed behind the engine 5. Although details are omitted, a handle shaft is rotatably disposed inside a handle post erected on the upper surface of the power steering unit 66. A steering handle 14 is fixed to the upper end side of the handle shaft. On the lower surface side of the power steering unit 66, a steering output shaft (not shown) protrudes downward. A steering rod 68 (see FIG. 4) for steering the left and right front wheels 3 is connected to the steering output shaft.

  The engine 5 of the embodiment is disposed on an intermediate portion of the front and rear base frames 56 with the output shaft 70 (crank shaft) directed in the left-right direction. The left and right widths of the engine 5 and the engine stand 57 are smaller than the inner dimensions between the left and right front frames 51, and the lower side of the engine 5 and the engine stand 57 are disposed on the middle part of the front and rear base frames 56. Thus, it is exposed below the left and right front frames 51. In this case, the output shaft 70 (axis line) of the engine 5 is in a position overlapping the left and right front frames 51 in a side view. An exhaust pipe 69 communicating with the exhaust system of the engine 5 is disposed on one of the left and right side surfaces (left side surface in the embodiment) of the engine 5. The proximal end side of the exhaust pipe 69 is connected to each cylinder of the engine 5, and the distal end side of the exhaust pipe 69 is connected to the exhaust inlet side of the muffler 65.

  In the driving operation unit 13 shown in FIG. 5, the traveling main speed change lever 15 is located on the left and right sides (in the embodiment, on the left side) sandwiching the steering handle 14. Along the guide groove 83 formed in the driving operation unit 13. The traveling mode of the rice transplanter 1 is switched to forward, neutral, reverse, seedling and movement modes by operating the traveling main speed change lever 15. The work lever 16 holds the steering handle 14 between them. The operation lever 16 is operated in a plurality of operations including raising / lowering operation of the seedling planting device 23, connection / disconnection operation of the planting clutch 77, and selection operation of the left / right side marker 33. Is configured to be operable in the cross direction.

  In this case, if the operation lever 16 is tilted forward once, the seedling planting device 23 is lowered, and if it is tilted forward once again, the planting clutch 77 is engaged and activated (becomes a power connection state). Conversely, when the operation lever 16 is tilted once backward, the planting clutch 77 is turned off (becomes in a power cut-off state), and when it is tilted again once, the seedling planting device 23 is raised. When stopping the raising / lowering operation of the seedling planting device 23, the operation lever 16 is tilted in the reverse direction. For example, when the lowering movement of the seedling planting device 23 is stopped halfway, the work lever 16 may be tilted backward. When the work lever 16 is tilted once to the left, the left side marker 33 is in the working position, and when it is tilted left again, the left side marker 33 is returned to the non-working position. When the work lever 16 is tilted to the right once, the right side marker 33 is in the working position, and when the work lever 16 is tilted to the right again, the right side marker 33 is returned to the non-working position.

  Next, the drive system of the rice transplanter 1 will be described with reference to FIG. The output shaft 70 of the engine 5 protrudes outward from the left and right side surfaces of the engine 5. An engine output pulley 72 is provided at the protruding end of the output shaft 70 that protrudes from the left side of the engine 5, a mission input pulley 73 is provided at the mission input shaft 71 that protrudes outward from the mission case 6, and is transmitted to both pulleys 72, 73. A belt 74 is wound around. Power is transmitted from the engine 5 to the transmission case 6 via both pulleys 72 and 73 and the transmission belt 74.

  In the transmission case 6, the transmission power through the hydraulic continuously variable transmission 40, the planetary gear device 41, the hydraulic continuously variable transmission 40, and the planetary gear device 41 including the hydraulic pump 40 a and the hydraulic motor 40 b is shifted to a plurality of stages. A gear-type sub-transmission mechanism 42, a main clutch 43 that interrupts power transmission from the planetary gear unit 41 to the gear-type sub-transmission mechanism 42, a traveling brake 44 that brakes the output from the gear-type sub-transmission mechanism 42, and the like. ing. The hydraulic pump 40a is driven by power from the mission input shaft 71, hydraulic oil is supplied from the hydraulic pump 40a to the hydraulic motor 40b, and variable speed power is output from the hydraulic motor 40b. The speed change power of the hydraulic motor 40 b is transmitted to the gear type subtransmission mechanism 42 via the planetary gear device 41 and the main clutch 43. Then, power is transmitted from the gear-type subtransmission mechanism 42 by branching in the two directions of the front and rear wheels 3 and 4 and the seedling planting device 2.

  Part of the branching power toward the front and rear wheels 3 and 4 is transmitted from the gear-type auxiliary transmission mechanism 42 via the differential gear mechanism 45 to the front axle 36 of the front axle case 7 to drive the left and right front wheels 3 to rotate. . The remainder of the branching power toward the front and rear wheels 3, 4 is transferred from the gear-type sub-transmission mechanism 42 through the universal joint shaft 46, the rear drive shaft 47 in the rear axle case 9, a pair of left and right friction clutches 48, and a gear-type reduction mechanism 49. Thus, the rear axle case 9 is transmitted to the rear axle 37 to drive the left and right rear wheels 4 to rotate. When the traveling brake 44 is operated, the output from the gear-type subtransmission mechanism 42 is lost, so that the front and rear wheels 3 and 4 are braked. When the rice transplanter 1 is turned, the friction clutch 48 inside the turning inside the rear axle case 9 is turned off to rotate the rear wheel 4 inside the turning freely, and the rotation of the rear wheel 4 outside the turning to which power is transmitted is rotated. It turns by driving.

  In the rear axle case 9, a rotor drive unit 86 having a leveling clutch 240 for power transmission to the leveling rotor 85 is provided. The power transmitted from the gear-type subtransmission mechanism 42 to the universal joint shaft 46 is also branched and transmitted to the rotor drive unit 86, and is transmitted from the rotor drive unit 86 to the leveling roller 85 via the universal joint shaft 87. The farm scene is leveled by the rotational drive of the leveling rotor 85.

  The branching power toward the seedling planting device 2 is transmitted to the inter-strain transmission case 75 via the PTO transmission shaft mechanism 74 with a universal joint shaft. In the inter-strain shifting case 75, an inter-strain shifting mechanism 76 that switches between seedlings to be planted, for example, to sparse planting, standard planting, or dense planting, and a planting clutch 77 that interrupts power transmission to the planting planting device 23 are provided. I have. The power transmitted to the inter-plant transmission case 75 is transmitted to the planting input case 26 via the inter-plant transmission mechanism 76, the planting clutch 77, and the universal joint shaft 78.

  In the planting input case 26, a horizontal feed mechanism 79 that moves the seedling platform laterally, a seedling vertical feed mechanism 80 that transports the seedling mat on the seedling platform 29 vertically, A planting output shaft 81 that transmits power to the planting transmission case 27 is provided. By the power transmitted to the planting input case 26, the lateral feed mechanism 79 and the seedling vertical feed mechanism 80 are driven, and the seedling stage 29 is continuously reciprocally moved in the lateral direction. The seedling mat on the seedling table 29 is intermittently transported vertically when reaching the turning point of the reciprocating movement. Power from the planting input case 26 via the planting output shaft 81 is transmitted to each planting transmission case 27, and the rotary case 31 and the planting claw 30 of each planting transmission case 27 are driven to rotate. In addition, when providing a fertilizer, motive power is transmitted from the inter-strain transmission case 75 to a fertilizer.

  Next, the hydraulic circuit structure of the rice transplanter 1 will be described with reference to FIG. The hydraulic circuit 90 of the rice transplanter 1 includes a hydraulic pump 40 a and a hydraulic motor 40 b that are components of the hydraulic continuously variable transmission 40, a charge pump 91, and a work pump 92. The hydraulic pump 40a, the charge pump 91, and the work pump 92 are driven by the power of the engine 5. The hydraulic pump 40 a and the hydraulic motor 40 b are connected to the respective suction side and discharge side via a closed loop oil passage 93. A charge pump 91 is connected to the closed loop oil passage 93. The swash plate angle of the hydraulic pump 40a is adjusted by driving the speed change electric motor according to the depression amount of the travel speed change pedal 12, and the hydraulic motor 40b is driven forward or reverse.

  The work pump 94 is connected to a power steering unit 66 that assists the operation of the steering handle 14. The power steering unit 66 includes a steering hydraulic pressure switching valve 94 and a steering hydraulic motor 95. By operating the steering handle 14, the steering hydraulic pressure switching valve 94 is switched to drive the steering hydraulic motor 95 to assist the operation of the steering handle 14. As a result, the left and right front wheels 3 can be easily steered with a small operating force.

  The power steering unit 66 is connected to the flow divider 96. The flow divider 96 is branched into a first oil passage 97 and a second oil passage 98. The first oil passage 97 is connected to a lift switching valve 99 that supplies hydraulic oil to the lift cylinder 39. The elevation switching valve 99 is a four-port two-position switching type mechanical switching that can be switched between a supply position 99a for supplying hydraulic oil to the elevation cylinder 39 and a discharge position 99b for discharging hydraulic oil from the elevation cylinder 39. It is a valve. The seedling planting device 23 is moved up and down via the lifting link mechanism 22 by operating the work lever 16 to switch the lifting switching valve 99 to expand and contract the lifting cylinder 96. The flow divider 96 and the up / down switching valve 99 are accommodated in a valve unit 89 provided at the rear of the mission case 6.

  An electromagnetic on-off valve 101 is provided in the cylinder oil passage 100 from the up / down switching valve 98 to the up / down cylinder 39. The electromagnetic on-off valve 101 is an electromagnetic control valve that can be switched between two positions: an open position 101a for supplying and discharging hydraulic oil to and from the lift cylinder 39 and a closed position 101b for stopping supply and discharge of hydraulic oil to and from the lift cylinder 39. is there. Accordingly, when the electromagnetic solenoid 102 is excited to open the electromagnetic on-off valve 101 to the open position 101a, the lifting cylinder 39 can be expanded and contracted, and the seedling planting device 23 can be moved up and down. When the electromagnetic solenoid 102 is de-energized and the electromagnetic on-off valve 101 is moved to the closed position 101b by the return spring 103, the elevating cylinder 39 is held so as not to expand and contract, and the seedling planting device 23 stops elevating at an arbitrary height position.

  An accumulator 105 is connected between the electromagnetic on-off valve 101 and the lift cylinder 39 in the cylinder oil passage 100 via an accumulator oil passage 104. When the operating hydraulic pressure in the elevating cylinder 39 changes suddenly, the operating hydraulic pressure fluctuation is absorbed by the accumulator 105, and the elevating cylinder 39 is smoothly expanded and contracted by the combination of the elevating switching valve 99 and the electromagnetic on-off valve 101, so The device 23 is moved up and down easily.

  The second oil passage 98 of the flow divider 96 is connected to a rolling control unit 106 that controls the right / left inclined posture of the seedling planting device 23. The rolling control unit 106 incorporates an electromagnetic control valve 107 that supplies hydraulic oil to the rolling cylinder 108. As a result of operating the rolling cylinder 108 provided integrally with the rolling control unit 106 by the switching operation of the electromagnetic control valve 107, the seedling planting device 23 is held in a horizontal posture. The hydraulic circuit 90 of the rice transplanter 1 also includes a relief valve, a flow rate adjustment valve, a check valve, an oil filter, and the like.

  Next, the detailed structure of the planetary gear device 41 and its periphery will be described with reference to FIGS. The power transmitted from the engine 5 to the mission input shaft 71 is shifted by the hydraulic continuously variable transmission 40 and the planetary gear unit 41. The hydraulic continuously variable transmission 24 includes a variable displacement hydraulic pump 40a and a fixed displacement hydraulic motor 40b. The power input from the mission input shaft 71 drives the hydraulic pump 40a, feeds hydraulic oil from the hydraulic pump 40a to the hydraulic motor 40b, and rotates the motor output shaft 195 of the hydraulic motor 40b.

  A pump output shaft 194 of the hydraulic pump 40a and a charge output shaft 196 are coaxially connected to the mission input shaft 71. In this case, a transmission gear 197 is fixed to the pump output shaft 194 of the hydraulic pump 40a. One end of a charge output shaft 196 arranged coaxially with the pump output shaft 194 is fixedly inserted into the transmission gear 197, and the charge pump 198 of the hydraulic continuously variable transmission 40 is fixed from the other end. Power is transmitted to the auxiliary pump 199.

  As shown in FIGS. 8 and 9, the planetary gear device 41 includes an internal gear 204, a sun gear 201 located on the inner diameter side of the internal gear 204, and a plurality of planets meshing with the internal gear 204 and the sun gear 201. A gear 203, a carrier 202 that rotatably supports each planetary gear 203, and a composite output shaft 205 that supports three members of the internal gear 204, the sun gear 201, and the carrier 202 are provided. In this case, the sun gear 201 and the carrier 202 having a toothed portion on the outer periphery can be pivotally supported on the motor output shaft 195 of the hydraulic motor 40b. The outer peripheral teeth of the carrier 202 are meshed with the transmission gear 197. A plurality of planetary gears 203 are rotatably provided around the sun gear 201. Each planetary gear 203 is rotatably supported on the carrier 202 via a support shaft 206. An internal gear 204 is meshed with the outside of the plurality of planetary gears 203. As described above, the planetary gear device 41 is configured by the sun gear 201, the carrier 202, the plurality of planetary gears 203, and the internal gear 204.

  By changing the angle of the movable swash plate of the hydraulic pump 40a in conjunction with the stepping operation of the traveling speed change pedal 12, hydraulic oil corresponding to the angle is sent from the hydraulic pump 40a. Then, the power (rotational speed) of the motor output shaft 195 of the hydraulic motor 40b is changed according to the amount of oil fed from the hydraulic pump 40a, and the sun gear 201 rotates at a speed corresponding to this power. On the other hand, when the pump output shaft 194 of the hydraulic pump 40a rotates, the transmission gear 197 and the carrier 202 rotate and the planetary gear 203 rotates. Thereafter, the planetary gear device 41 combines the power of the sun gear 201 and the power of the planetary gear 203, and the combined power is output from the combined output shaft 205 that is fitted to the internal gear 204 via the sleeve 207. That is, the combined output shaft 205 rotates or stops at a speed corresponding to the angle of the movable swash plate of the hydraulic pump 40a.

  A sleeve 207 is fitted on the composite output shaft 205. The internal gear 204 is fitted on the sleeve 206. A liner 208 is disposed on one side of the sun gear 201 opposite to the carrier 202. The outer diameter DL of the liner 208 is set to a size that fits inside the plurality of planetary gears 203 surrounding the sun gear 201. Of the support shaft 206 of each planetary gear 203, the protruding end side opposite to the carrier 202 is supported by an annular plate washer 209. The washer 209 is detachably locked to the protruding end side of each support shaft 206 via a retaining ring 210. The inner diameter DW of the washer 209 is set smaller than the outer diameter DL of the liner 208. Through the washer 209 and the liner 208, the protruding end side 205 a protruding from the sleeve 207 of the composite output shaft 205 is inserted into the sun gear 201. The projecting end side 205a of the composite output shaft 205 is rotatably supported by a bearing 211 (needle bearing) provided in the sun gear. The protruding end side 205a of the composite output shaft 205 is formed in a tapered shape or a chamfered shape whose diameter decreases as it approaches the protruding end.

  The planetary gear device 41 is assembled as follows, for example. The planetary gear 203 is rotatably supported on each support shaft 206 attached to the carrier 202. The boss 201a of the sun gear 201 is rotatably inserted into the carrier 202 while meshing the sun gear 201 and each planetary gear 203. A liner 208 is disposed on one side surface of the sun gear 201 opposite to the carrier 202 so as to fit inside the plurality of planetary gears 203. A washer 209 is attached to the projecting end of the planetary gear 203 opposite to the carrier 202 on the support shaft 206. In this case, since the inner diameter DW of the washer 209 is smaller than the outer diameter DL of the liner 208, the liner 208 has a plurality of positions between the sun gear 201 and the washer 209 even when the composite output shaft 205 is not inserted. It is accommodated (temporarily held) so as to be surrounded by the planetary gear 203. Then, the internal gear 204 is fitted on the composite output shaft 205 via the sleeve 207, and the internal gear 204 and the plurality of planetary gears are engaged with each other while the washer 209 and the liner 208 are engaged. The protruding end 205 a protruding from the sleeve 207 is inserted into the sun gear 201.

  According to the above embodiment, the internal gear 204, the sun gear 201 located on the inner diameter side of the internal gear 204, the plurality of planetary gears 203 meshed with the internal gear 204 and the sun gear 201, In the planetary gear device 41, which includes a carrier 202 that rotatably supports the planetary gear 203, and an output shaft 205 that supports the internal gear 204, the sun gear 201, and the carrier 202. The carrier 202 is rotatably supported by the boss 201a of the 201, while the internal gear 204 is fitted on the sleeve 207 fitted on the output shaft 205, and the sun gear 201 is opposite to the carrier 202. A liner 208 is disposed on one side surface of the support shaft 206 of each planetary gear 203, and the protruding end side opposite to the carrier 202 is arranged on the side surface of the planetary gear 203. The washer 209 is supported, the inner diameter DW of the washer 209 is made smaller than the outer diameter DL of the liner 208, and the protruding end side of the output shaft 205 protruding from the sleeve 207 via the washer 209 and the liner 208. Is inserted into the sun gear 201, the interference of the sleeve 207 with the sun gear 201 can be prevented by the presence of the liner 208, and the sun gear 201 is assembled when the planetary gear device 41 is assembled. Thus, the liner 208 can be temporarily held between the washer 209 and the assembling workability of the planetary gear unit 41 can be improved. The presence of the liner 208 also contributes to prevention and positioning of a bearing 211 (needle bearing) that rotatably supports the protruding end 205a of the combined output shaft 205.

  Further, the protruding end side 205a of the output shaft 205 protruding from the sleeve 207 is formed in a tapered shape or a chamfered shape whose diameter decreases as it approaches the protruding end. The projecting end side 205a is smoothly passed through the liner 208 (contained inside the plurality of planetary gears 203) temporarily held between the sun gear 201 and the washer 209, and then the sun gear 201 is inserted. The assembly workability of the planetary gear device 41 can be further improved.

  Next, the leveling rotor 85 as a leveling device and its peripheral structure will be described with reference to FIGS. As described above, the leveling rotor 85 as a leveling device for leveling the farm scene is provided on the front side of the seedling planting device 23 located behind the traveling machine body 1 so as to be movable up and down. The leveling rotor 85 includes left and right longitudinal rotor shafts 221, a plurality of blade-like rotor pieces 222 provided on the outer peripheral side of the rotor shaft 221, a rotor transmission case 223 disposed in the longitudinal middle portion of the rotor shaft 221, and the rotor pieces 222. And a rotor cover 224 that covers the upper side. The power transmitted to the rotor drive unit 86 is transmitted to the rotor shaft 221 via the universal joint shaft 87 to rotate the rotor shaft 221 and the rotor piece 222. By rotation of the rotor piece 222, the left and right rice fields of the seedling planting device 23 (rice fields having a planting width for six strips) are leveled.

  On the front side of the seedling planting device 23, a rotor lifting mechanism 225 for moving the leveling rotor 85 up and down by manual operation of the rotor lifting handle 226 is disposed. The rotor lifting mechanism 255 includes an upper link 227 and a lower link 228 that constitute a parallel link mechanism, and a rotor frame 230 that is connected to left and right side frames 229 that are the framework of the seedling planting device 23 via upper and lower links 227 and 228. It has. A rotor shaft 221 is rotatably connected to the lower ends of the left and right rotor frames 230. A horizontally elongated rotor elevating fulcrum shaft 232 is pivotally supported on the intermediate bracket 231 of the side frame 229 so as to be rotatable. One end side of the upper link 227 is fixed to the rotor lifting fulcrum shaft 232. The other end side of the upper link 227 is rotatably connected to the upper end side of the rotor frame 230. One end side of the lower link 228 is rotatably connected to the lower bracket 232 of the side frame 229. The lower end side of the lower link 228 is rotatably connected to the midway portion of the rotor frame 230.

  The base end side of the rotor lifting handle 226 is fixed to one end side (for example, the right end side) of the rotor lifting support shaft 232 by welding or the like. The rotor lifting handle 226 extends forward. The right side frame 229 is provided with a handle bracket 233 that removably engages the longitudinal middle portion of the rotor lifting handle 226. The rotor lifting handle 226 is held at the operating position by the handle bracket 233. The handle bracket 233 is formed with a plurality of notches (not shown) for releasably engaging the rotor lifting handle 226.

  When the operator grasps the rotor lifting handle 226 and rotates it up and down, the upper link 227 rotates around the rotor lifting fulcrum shaft 232, and the leveling rotor 85 is moved by the vertical links 227 and 228 through the rotor frame 230. As a result, the leveling rotor 85 moves to the ascending position (non-working position) or the descending position (landing work position). By engaging the rotor lifting handle 226 with the notch of the handle bracket 233, the leveling rotor 85 is held at a predetermined height position. In addition, since the raising / lowering movement of the leveling rotor 85 in the embodiment is performed in a manner not interlocked with the seedling planting device 23, even if the seedling planting device 23 is in the lowered position (landing work position), the leveling rotor 85 Can be supported in the raised position (non-working position).

  As shown in FIG. 9, the front end side of the wire connecting arm 234 protruding backward is fixed to the rotor lifting fulcrum shaft 232 by welding or the like. One end side of the clutch interlocking wire 236 is connected to the rear end side of the wire connecting arm 234 via a wire connecting piece 235. The other end side of the clutch interlocking wire 236 is connected to the rear end side of the clutch switching arm 237 provided on the left outer surface of the left vertical frame 62. A longitudinally middle portion of the clutch switching arm 237 that is long in the front-rear direction is pivotally supported by the left vertical frame 62 so as to be rotatable. The front end side of the clutch switching arm 237 is connected to the clutch operating arm 239 of the rear axle case 9 via a connecting rod 238.

  When the leveling rotor 85 moves to the ascending position (non-working position) or the descending position (landing work position), the clutch switching arm 237 rotates via the clutch interlocking wire 236 in conjunction with the vertical movement of the leveling rotor 85. Then, the clutch operating arm 239 rotates via the connecting rod 238, and the leveling clutch 240 that interrupts power transmission to the leveling rotor 85 is turned on and off. For example, when the operator turns the rotor lifting handle 226 upward to raise the leveling rotor 85 to a predetermined height position, the leveling clutch 240 is turned off via the clutch interlocking wire 236. When the leveling rotor 85 is lowered to a predetermined height position by rotating the rotor lifting handle 226 downward, the leveling clutch 240 is engaged and operated via the clutch interlocking wire 236.

  As shown in detail in FIG. 10, the rear axle case 9 includes a rear input unit 241 having a rear input shaft 242 connected to a universal joint shaft 46 extending along the cylindrical frame 8, and power of the rear input shaft 242. Rear drive shaft 47 that transmits to the rear wheel 4 via the left and right rear axles 37, a friction clutch 48 that is disposed on each of the left and right sides of the rear drive shaft 47, and a leveling drive in which the power of the rear input shaft 242 is branched and transmitted. And a rotor drive unit 86 having a shaft 243 and a leveling clutch 240. The leveling drive shaft 243 is connected to the rotor shaft 221 of the leveling rotor 85 via the universal joint shaft 87. A rear axle case lid 244 that supports the rear axle 37 is attached to the left and right outer sides of the rear axle case 9 (the left and right outer sides of a rear axle case portion 9b described later). A final gear mechanism 245 for transmitting the power of the rear drive shaft 47 to the rear axle 37 is disposed in the rear axle case lid 244. As shown in FIG. 9, the rear end side of the leveling drive shaft 243 connected to the front end side of the universal joint shaft 87 is at the same height as the rear axle 37. For this reason, the raising / lowering range of the leveling rotor 85 accompanying the raising / lowering motion of the seedling planting apparatus 23 is ensured, without making the inclination-angle of the universal joint axis | shaft 87 excessive.

  The rear input shaft 242 extending in the front-rear direction is provided on the left side of the rear axle case 9 with the cylindrical frame 8 interposed therebetween. The left and right longitudinal rear drive shaft 47 is disposed behind the rear input shaft 242. The rear drive shaft 47 is pivotally supported on the rear axle case 9 via rear drive shaft bearings 246 and 247. Similarly to the rear input shaft 242, the leveling drive shaft 243 extending forward and backward is disposed below the rear input shaft 242 and offset to the left side of the rear input shaft 242. The leveling drive shaft 243 is positioned below the rear input shaft 242 and the rear drive shaft 47. The leveling drive shaft 243 extends in the front-rear direction so as to be parallel to the rear input shaft 242 and intersect the rear drive shaft 47.

  The rear axle case 9 includes an input shaft case portion 9 a that houses the rear input shaft 242, left and right rear axle case portions 9 b that support the rear axle 37, and a main body case portion 9 c that houses the rear drive shaft 47. Is forming. A drive shaft case portion 9d that accommodates the leveling drive shaft 243 is formed on the lower side of the main body case portion 9c. The drive shaft case 9d is positioned below the input shaft case 9a. That is, the rear axle case 9 is provided with an input shaft case portion 9a and a drive shaft case portion 9d in two upper and lower layers.

  The input shaft case portion 9a is formed with a forward shaft hole 251 that opens forward. A rear input unit 241 is detachably inserted into the forward shaft hole 251. The rear input unit 241 includes a rear input shaft 242 that extends back and forth along the forward shaft hole 251, front and rear input shaft bearings 252 and 253 that support the rear input shaft 242, a rear drive shaft 47, and a leveling drive shaft 243. And a transmission gear body 254 for transmitting power. The front and rear input shaft bearings 252 and 253 fitted on the rear input shaft 242 are detachably fitted to the inner diameter side of the forward shaft hole 251.

  The transmission gear body 254 is provided on the rear end side of the rear input shaft 242. The transmission gear body 254 of the embodiment integrally includes a rear drive shaft bevel gear 255 that distributes the power of the rear input shaft 242 to the rear drive shaft 47 and a leveling drive shaft flat gear 256 that distributes the power to the leveling drive shaft 243. Is formed. The rear drive shaft bevel gear 255 meshes with an interlocking bevel gear 257 provided on the rear drive shaft 47. The leveling drive shaft flat gear 256 meshes with the interlocking flat gear 258 provided on the leveling drive shaft 243. Note that the tip diameter of the flat gear 256 for leveling drive shaft is smaller than the inner diameter of the forward shaft hole 251.

  Since the rear drive shaft bevel gear 255 and the leveling drive shaft flat gear 256 are integrally formed, the rear input shaft is rearward by the arrangement dimension of the leveling drive shaft flat gear 256 (the thickness of the leveling drive shaft flat gear 256). The transmission gear body 254 can be disposed on the rear input shaft 242 in the rear axle case 9 simply by extending the 242. Further, a leveling drive shaft flat gear 256 (transmission gear body 254) is disposed on the rear end side of the rear input shaft 242 so that power can be transmitted to the middle part of the leveling drive shaft 243 on the rear end side of the rear input shaft 242. By connecting, the leveling drive shaft 243 is accommodated within the front-rear width of the rear axle case 9 (drive shaft case portion 9d). The rear input unit 241 is configured by fitting the front and rear input shaft bearings 252 and 253 and the transmission gear body 254 to the rear input shaft 242. Therefore, the rear input unit 241 can be easily inserted into the forward axle hole 251 from the front of the rear axle case 9 (input shaft case portion 9a), and the rear input unit 241 can be detachably attached to the rear axle case 9. In the transmission gear body 254, the diameter of the root circle of the flat gear 256 for leveling drive shaft is set to be larger than the diameter of the tip circle of the bevel gear 255 for rear drive shaft.

  As shown in FIGS. 10 and 14, a friction clutch 48 is provided at the left and right ends of the rear drive shaft 47. A friction clutch cam shaft 261 for turning the friction clutch 48 on and off is disposed inside the left and right sides of each friction clutch 48. Although not shown in detail, the friction clutch 48 has a multi-plate structure, and is configured to be turned off when the steering handle 14 is turned to a predetermined steering angle or more.

  In this case, the front end side of the intermediate rod 262 (see FIGS. 1 and 4) extending in the front-rear direction is connected to a steering output shaft (not shown) protruding downward from the lower surface of the power steering unit 66. The rear end side of the intermediate rod 262 is connected to one end side of a rotating arm 263 (see FIG. 14) disposed on the lower surface side of the rear axle case 9. The intermediate rod 262 is configured to push and pull back and forth in conjunction with the rotation of the steering output shaft. As shown in detail in FIG. 14, the other end side of the rotating arm 263 is fixed to the lower end side of the relay fulcrum shaft 264 that penetrates the rear axle case 9 vertically. The upper end side of the relay fulcrum shaft 264 is fixed to the middle part of the operating arm 265 disposed on the upper surface side of the rear axle case 9. The rotating arm 263, the relay fulcrum shaft 264, and the operating arm 265 rotate integrally around the relay fulcrum shaft 264. When the steering handle 14 is rotated, the intermediate rod 262 is pushed and pulled in the front-rear direction in conjunction with this, and the operating arm 265 rotates about the relay fulcrum shaft 264 together with the rotating arm 263.

  The left and right end portions of the operating arm 265 are provided so as to be able to contact and separate from the distal ends of the pair of left and right intermediate arms 266 (see FIG. 4). The actuating arm 265 is displaced to a position that does not contact any of the intermediate arms 266 or a position that presses any one of the intermediate arms 266 by rotating around the relay fulcrum shaft 264. The base end side of each intermediate arm 266 is fixed to a protruding end portion of the friction clutch cam shaft 261 that protrudes upward from the upper surface of the rear axle case 9 (main body case portion 9c). The cam surface of the friction clutch cam shaft 261 is in contact with the left and right inner sides of the friction clutch 48. The friction clutch 48 is turned on and off by the rotation of the friction clutch cam shaft 261.

  For example, when turning the steering handle 14 to a predetermined steering angle or more to change the direction on a headland in a farm field, the intermediate rod 262 is pushed or pulled, via the turning arm 263 and the relay fulcrum shaft 264. As a result, the operating arm 265 rotates and the left and right ends of the operating arm 265 press the intermediate arm 266 corresponding to the friction clutch 48 inside the turning. When the intermediate arm 266 is pressed, the friction clutch cam shaft 261 is rotated and the friction clutch 48 inside the turning is turned off to rotate the rear wheel 4 inside the turning freely. The rice transplanter 1 turns by the rotational drive of the rear wheel 4 outside the turn to which power is transmitted. As a result, the turning radius of the rice transplanter 1 is reduced (turning performance is improved). Note that when the steering handle 14 is turned to a predetermined steering angle or less, the friction clutch 48 is held in the engaged state (power connection state) both inside and outside the turning. For this reason, it is possible to prevent the meandering traveling greatly due to the turning operation of the steering handle 14, and the alignment steering performance (straight traveling performance) is high.

  As shown in FIGS. 10 and 14, the leveling drive shaft 243 is not offset directly below the rear input shaft 242 but is offset from the rear input shaft 242. For this reason, in the rear axle case 9, it is possible to avoid the possibility that the connecting portion between the rear input shaft 242 and the rear drive shaft 47 and the connecting portion between the rear input shaft 242 and the leveling drive shaft 243 interfere with each other. Even when a structure (rotor drive unit 86) for branching and transmitting power from the rear input shaft 242 to the leveling drive shaft 243 is provided in the rear axle case 9, the increase in the vertical height of the rear axle case 9 is reduced. As a result, the rear axle case 9 can be prevented from being enlarged (downsizing can be achieved). The offset amount L of the leveling drive shaft 243 with respect to the rear input shaft 242 is set such that the leveling drive shaft 243 and the rear input shaft 242 overlap (wrap) in plan view. Therefore, the attachment position of each friction clutch 48 is unlikely to be limited by the presence of a structure (rotor drive unit 86) that branches and transmits power from the rear input shaft 242 to the leveling drive shaft 243. 9 can ensure the degree of freedom of the layout of each friction clutch 48.

  As shown in FIGS. 11 and 12, the drive shaft case portion 9d of the rear axle case 9 is formed with a rear shaft hole 271 that opens rearward. A rotor drive unit 86 is detachably inserted into the rearward shaft hole 271. The rotor drive unit 86 includes a leveling drive shaft 243 extending back and forth along the rearward shaft hole 271, front and rear drive shaft bearings 272 and 273 that support the leveling drive shaft 243, and a leveling drive shaft flat of the rear input shaft 242. The interlocking flat gear 258 that meshes with the gear 256, the leveling clutch 240 that interrupts power transmission from the rear input shaft 242 to the leveling drive shaft 243, and the power transmission to the leveling drive shaft 243 can be limited separately from the leveling clutch 240 The torque limiter 274 is provided.

  Front and rear drive shaft bearings 272 and 273 fitted on the leveling drive shaft 243 are detachably fitted to the inner diameter side of the rearward shaft hole 271. The drive shaft bearings 272 and 273 are arranged separately on the front end side and the rear end side of the leveling drive shaft 243. The interlocking flat gear 258 is disposed in the middle of the longitudinal axis of the leveling drive shaft 243. The leveling clutch 240 is disposed on the front end side of the leveling drive shaft 243, and the torque limiter 274 is disposed on the rear end side of the leveling drive shaft. That is, with respect to the leveling drive shaft 243, the leveling clutch 240 is positioned on the power transmission downstream side, and the torque limiter 274 is positioned on the power transmission upstream side. Needless to say, the diameter of the tip of the interlocking flat gear 258 is smaller than the inner diameter of the rear shaft hole 271 on the rear side.

  As shown in FIGS. 11 and 12, the drive shaft bearings 272 and 273, the interlocking flat gear 258, the leveling clutch 240 and the torque limiter 274 are fitted on the leveling drive shaft 243 to constitute the rotor drive unit 86. ing. For this reason, the rotor drive unit 86 can be easily inserted into the rear axle case 9 detachably by inserting the rotor drive unit 86 into the rear axle hole 271 from the rear of the rear axle case 9 (drive shaft case portion 9d). Since a dedicated power take-out case that accommodates the rotor drive unit 86 is not required as in the prior art, the number of parts can be reduced, and the manufacturing cost can be reduced.

  In the embodiment, the front drive shaft bearing 272 is detachably fitted in a bearing fitting recess 275 formed closer to the front portion on the inner diameter side of the rearward shaft hole 271. The rear drive shaft bearing 273 is detachably fitted to the rear side of the inner diameter of the rear shaft hole 271. Accordingly, the rotor drive unit 86 is inserted into the rear axle hole 271 from the rear of the rear axle case 9 so that the front drive shaft bearing 272 is fitted into the bearing fitting recess 275, whereby the rotor drive unit 86 is moved to the rear axle. The drive shaft case portion 9d of the case 9 is attached. In the case of a specification that does not include the leveling rotor 85, the rotor drive unit 86 (drive shaft bearings 272 and 273, interlocking flat gear 258, leveling clutch 240, torque limiter) is started from the drive shaft case portion 9 d of the rear axle case 9. 274 and the combination of the leveling drive shaft 243) are removed, and the rear opening of the rearward shaft hole 271 is closed with a sealing lid 276 (see FIG. 12).

  That is, the configuration of the rear axle case 9 can be easily changed to the specification with the leveling rotor 85 or the specification without the leveling rotor 85 by attaching and detaching the rotor drive unit 86 and detaching the sealing lid 276. There is no need to change the specifications by exchanging the rear axle case 9. For example, even after the rice transplanter 1 is shipped without the leveling rotor 85, the sealing lid 276 is removed and the rear shaft hole 271 is driven by the rotor. By simply inserting the unit 86, it can be changed to the specification with the leveling rotor 85. One type of rear axle case 9 can be shared by two specifications with and without a leveling rotor 85, and the production cost can be reduced as a whole model.

  A leveling clutch 240 is provided on the front side of the leveling drive shaft 243. The leveling clutch 240 includes a leveling slider 281 that is spline-fitted to the leveling drive shaft 243 so as to slide forward and backward, a clutch spring 283 that presses and biases the leveling slider 281 rearward, and leveling against the clutch spring 283. A clutch cam shaft 284 for sliding the slider 281 is provided. A fixed clutch pawl 282 is formed on the rear end side of the leveling slider. An idler cylinder 286 having an idler side clutch pawl 287 on the front end side is fitted on the rear side of the leveling drive shaft 243 so as to be relatively rotatable and non-slidable.

  The clutch spring 283 is wound around the leveling drive shaft 243 between the front end side of the leveling slider 281 and the front drive shaft bearing 272. A hook-shaped cam engagement piece 285 is formed on the outer periphery of the front end of the leveling slider 281 so as to project outward in the radius direction. One end side cam portion of the clutch cam shaft 284 is locked to the cam engagement piece portion 285. The front end side of the clutch cam shaft 284 protrudes outward from the left side surface of the rear axle case 9 (drive shaft case portion 9d), and the clutch operating arm 239 is connected to the protruding end portion of the clutch cam shaft 284. The leveling slider 281 is configured to slide back and forth on the leveling drive shaft 243 by the rotation of the clutch operating arm 239. When the leveling slider 281 is slid rearward by the rotation of the clutch operating arm 239 and the elastic biasing force of the clutch spring 283, the fixed clutch pawl 282 is engaged with the free-side clutch pawl 287, An idler cylinder 286 is connected to the leveling slider 281 and thus to the leveling drive shaft 243 via the 287 so as to be integrally rotatable.

  An interlocking flat gear 258 is fitted on the front side of the idler cylinder 286 so as to be relatively rotatable and non-slidable. A gear side engaging claw 288 is formed on the rear surface side of the interlocking flat gear 258. A limiter slider 289 constituting the torque limiter 274 is spline-fitted to the midway part of the idler cylinder 286 so as to be slidable back and forth. A slider side engaging claw 290 that can be locked to the gear side engaging claw 288 is formed on the front surface side of the limiter slider 289. A spring seat 291 is fixed to the rear side of the idler cylinder 286. A torque spring 292 is wound around the idler cylinder 286 between the front end side of the limiter slider 289 and the spring seat 291. A combination of the idler cylinder 286, the interlocking flat gear 258 with the gear side engagement claw 288, the limiter slider 289 with the slider side engagement claw 290, and the torque spring 292 constitute a torque limiter 274.

  Normally, the limiter slider 289 is slid forward by the elastic biasing force of the torque spring 292, and the slider side engaging claw 290 is locked to the gear side engaging claw 288. Since the limiter slider 289 is spline-fitted to the idler cylinder 286, the interlocking flat gear 258 is coupled to the idler cylinder 286 via the limiter slider 289 so as to be integrally rotatable. When the leveling clutch 240 is engaged and operated in this state, the idler cylinder 286 is coupled to the leveling slider 281 and thus the leveling drive shaft 243 via the fixed side and idler side clutch claws 282 and 287 so that they can rotate together. The flat gear 258 is connected to the leveling drive shaft 243 via the limiter slider 289, the idler cylinder 286, and the leveling slider 281 so as to be integrally rotatable. That is, the interlocking flat gear 258 is connected to the leveling drive shaft 243 via the limiter slider 289, the idler cylinder 286, and the leveling slider 281 so that power can be transmitted.

  On the other hand, when the leveling rotor 85 receives a large resistance from muddy water or mud or bites foreign matter and the transmission torque applied to the torque limiter 274 exceeds a predetermined value (overload state), it resists the elastic biasing force of the torque spring 292. Thus, the engagement between the slider-side engagement claw 290 and the gear-side engagement claw 288 slips and is released. Then, the interlocking flat gear 258 idles on the idler cylinder 286, and the rotational power transmitted from the rear input shaft 242 to the leveling drive shaft flat gear 256 of the transmission gear body 254 is at the interlocking flat gear 258. It is blocked and is not transmitted to the leveling drive shaft 243. That is, the power transmission to the leveling drive shaft 243 is limited, and the overload applied to the leveling drive shaft 243 can be easily released by the torque limiter 274.

  As is clear from the above description and FIGS. 11 and 12, the traveling machine body 2 on which the engine 5 is mounted, the seedling planting device 23 mounted on the rear end side of the traveling machine body 2, and the left and right rear wheels 4 are supported. In the rice transplanter 1 provided with a rear axle case 9 and a leveling device 85 for leveling the planted rice field, the rear axle case 9 has a rear input shaft 242 for transmitting the power of the engine 5 and the rear input. Since the leveling drive shaft 243 that branches the power of the shaft 242 and transmits it to the leveling device 85 is provided, and the leveling drive shaft 243 is provided with a torque limiter 274, for example, the soil quality of the field is hard and the mud and mud When the leveling device 85 receives a large resistance or bites foreign matter, an overload applied to the leveling drive shaft 243 can be easily released by the torque limiter 274.Accordingly, it is possible to prevent problems caused by excessive driving of the leveling device 85, for example, damage to the drive system such as the leveling drive shaft 243 and the leveling device 85 itself. There is also an advantage that the torque limiter 274 can be compactly assembled in the rear axle case 9 by using the leveling drive shaft 243 that transmits power to the leveling device 85.

  Further, a leveling clutch 240 for interrupting power transmission from the rear input shaft 242 is provided on the leveling drive shaft 243, the leveling clutch 240 is positioned on the power transmission downstream side, and the torque limiter 274 is positioned on the power transmission upstream side. Therefore, not only the torque limiter 274 but also the leveling clutch 240 can be compactly assembled in the rear axle case 9 by using the leveling drive shaft 243 that transmits power to the leveling device 85. Further, the space for arranging the leveling drive shaft 243, the torque limiter 274, and the leveling clutch 240 can be easily secured in the rear axle case 9.

  Further, a rearward shaft hole 271 that houses the leveling drive shaft 243 is formed in the rear axle case 9 so as to open toward the rear surface side of the rear axle case 9, and from the rearward shaft hole 271 to the rear of the rear axle case 9. In addition, since the leveling drive shaft 243 can be extracted together with the leveling clutch 240 and the torque limiter 274, the combination of the leveling drive shaft 243, the torque limiter 274 and the leveling clutch 240 is used as one unit for the rear axle. The case 9 can be easily attached and detached. For this reason, it is possible to easily cope with specifications with or without the leveling device 85. In addition, one type of rear axle case 9 can be shared by two specifications with and without the leveling device 85, and the manufacturing cost can be reduced as a whole model.

  The present invention is not limited to the above-described embodiment, and can be embodied in various forms. The configuration of each part is not limited to the illustrated embodiment, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Rice transplanter 2 Traveling machine body 5 Engine 9 Rear axle case 23 Seedling planting device 85 Leveling rotor (leveling device)
86 Rotor drive unit 87 Universal joint shaft 240 Leveling clutch 241 Rear input unit 242 Rear input shaft 243 Leveling drive shaft 258 Interlocking flat gear 271 Rear shaft hole 274 Torque limiter 281 Leveling slider 282 Fixed side clutch pawl 283 Clutch spring 284 Clutch cam Shaft 285 Cam engaging piece 286 Free rotating cylinder 287 Free side clutch claw 288 Gear side engaging claw 289 Limiter slider 290 Slider side engaging claw 291 Spring seat 292 Torque spring

Claims (1)

In a rice transplanter equipped with a traveling machine body equipped with an engine, a seedling planting device mounted on the rear end side of the traveling machine body, a rear axle case supporting left and right rear wheels, and a leveling device for leveling the planted rice field ,
The rear axle case includes a rear input shaft to which power of the engine is transmitted, and a leveling drive shaft that branches the power of the rear input shaft and transmits the power to the leveling device.
When viewed in the radial direction of the rear input shaft, the rear input shaft and the front side of the leveling drive shaft are positioned so as to overlap with each other, and the longitudinal intermediate portion of the leveling drive shaft is located at the rear end side of the rear input shaft. Are connected so that power can be transmitted,
A rearward shaft hole that houses the leveling drive shaft is formed in the rear axle case so as to open toward the rear surface side of the rear axle case,
The front side of the ground leveling drive shaft, a ground leveling clutch Tsugidan the power transmission from the rear input shaft is provided, on the rear side of the ground leveling drive shaft, which can limit the power transmission to the ground leveling drive shaft the torque limit data is provided, the power transmitted to the rear input shaft, through said ground leveling clutch from the torque limiter may be configured to transmit to the ground leveling drive shaft,
The size of the opening of the rear shaft hole is larger than that of the leveling clutch and the torque limiter so that the leveling drive shaft together with the leveling clutch and the torque limiter can be extracted from the rear shaft hole to the rear of the rear axle case. Set large,
Rice transplanter.

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