JP2018090217A - Work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a work vehicle that prevents a turning-inner-side rear wheel from digging the ground during turning so that roughing of a work place is reduced.SOLUTION: A work vehicle 1 is equipped with: a travelling machine body 2 mounted with an engine 5; left and right travelling parts 4 supporting the travelling machine body 2; a steering controller 14 for changing and controlling an advancing direction of the travelling machine body 2; and left and right main connecting/disconnecting members 48 which connect and disconnect power transmission to the left and right travelling parts 4, which activates the main connecting/disconnecting members 48 to disconnect the power transmission to the travelling parts 4 inside turning according to steering control by the steering controller 14, and further comprises left and right sub connecting/disconnecting members 111 and deceleration mechanisms 131 disposed separately from the left and right main connecting/disconnecting members 48. Accompanying the connection of power transmission by the main connecting/disconnecting members 48 to the travelling parts 4 inside turning, the sub connecting/disconnecting members 111 are connected to the travelling parts 4 inside turning and activated, so that power going toward the travelling parts 4 inside turning goes through the deceleration mechanisms 131 or goes through the sub connecting/disconnecting members 111 and the deceleration mechanisms 131, and drives the travelling parts 4 inside turning at speed lower than speed of the travelling parts 4 outside turning.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a work vehicle such as a rice transplanter that continuously performs seedling planting work.

  In general, a riding type rice transplanter, which is an example of a work vehicle, includes a steering handle that changes a traveling direction of a traveling machine body, and left and right side clutches that relay power transmission to left and right rear wheels. The side clutch for the rear wheel on the inside of the turn is cut off according to the steering operation of the steering handle (see, for example, Patent Documents 1 and 2). In such a work vehicle, when the steering handle is largely steered to the left or right, the side clutch for the rear wheel inside the turn is cut off, and the rear wheel inside the turn is in a freely rotating state. For this reason, for example, in rice fields, it is possible to make a U-turn turn at the heel when moving to the adjacent strip.

JP 2001-95335 A JP 2002-340021 A

  However, in this type of work vehicle, three-wheel drive is performed when the U-turn is turned. For example, in Fukada, the resistance against rotation of the wheel is large, so that the rear wheel inside the turn hardly turns and changes direction on the spot. As a result, the ground is dug by the rear wheels on the inside of the turn to roughen work areas such as farm fields. Further, when the work site is Fukada, the rear wheel inside the turn sinks during U-turn turning, which causes resistance to traveling of the work vehicle, which may cause the work vehicle to sink.

  This invention makes it the technical subject to provide the work vehicle which considered the above present conditions and improved.

  A work vehicle according to the present invention includes a traveling machine body equipped with an engine, left and right traveling units that support the traveling machine body, a steering operation tool that changes a traveling direction of the traveling machine body, and left and right traveling units. Left and right main severing members for severing power transmission, and a work vehicle that operates to cut off the main severing member with respect to the traveling part inside the turn according to the steering operation of the steering operating tool. In addition to the left and right main connection members, the left and right sub-connection members and a speed reduction mechanism are provided, and the main connection member with respect to the traveling unit on the inside of the turn is cut off with respect to the traveling unit on the inside of the turn. By connecting and operating the sub-connection member, the power toward the traveling part inside the turn drives the traveling part inside the turn at a lower speed than the traveling part outside the turn via the speed reduction mechanism. It is.

  The work vehicle of the present invention includes a rear axle case supported by left and right rear wheels as the left and right traveling units, and a rear input shaft to which the engine power is transmitted and the rear input in the rear axle case. A laterally long rear drive shaft that branches the shaft power and transmits it to the left and right rear wheels, and the left and right main connection members, the sub-connection members, and the speed reduction mechanism are disposed on the rear drive shaft. You may make it do.

  In the work vehicle of the present invention, the main connection member is disposed on the left and right inner sides of the rear drive shaft, and the sub-connection member and the speed reduction mechanism are disposed on the left and right outer sides of the rear drive shaft with respect to the main connection member. The transmission torque capacity of the sub-connection member may be set smaller than that of the main connection member.

  In the work vehicle of the present invention, a single cam member that rotates left and right in conjunction with the steering operation of the steering operation tool, and a left and right main severing operation mechanism that severing the left and right main severing members. And a left and right sub-severing operation mechanism for performing a joint operation on the left and right sub-severing members, provided in the rear axle case, and a shut-off operation of the main joint operating mechanism with respect to the traveling part inside the turning, and a turning inside Both the connection operation of the sub-separation operation mechanism with respect to the traveling unit may be executed by turning the cam member to the left and right.

  In the work vehicle of the present invention, the cam member and the left and right cams may be connected to the cam member so that the main connecting member for the traveling portion inside the turning is in a power cut-off state and the sub-connecting member for the traveling portion inside the turning is connected. The main severing operation mechanism and the left and right sub severing operation mechanisms may be associated with each other.

  A work vehicle according to the present invention includes a traveling machine body equipped with an engine, left and right traveling units that support the traveling machine body, a steering operation tool that operates to change a traveling direction of the traveling machine body, and left and right traveling units. Left and right main severing members for severing power transmission, and a work vehicle that shuts off the main severing member with respect to the traveling part inside the turn according to the steering operation of the steering operation tool, Separately from the left and right main connection members, the left and right sub-connection members and a speed reduction mechanism are provided. By connecting and operating the sub-connection member, the power toward the traveling part inside the turn is driven through the speed reduction mechanism to drive the traveling part inside the turn at a lower speed than the traveling part outside the turn. So you can always turn with four-wheel drive By eliminating a state in which the running portion of the inside of the turn is dig the ground to change the orientation on the fly without rotating, running portion of the inside of the turn can be reduced a state in which the roughening the work area at the time of turning. Moreover, since it always turns by four-wheel drive, for example, when a work place is a rice field, sinking of a work vehicle can be reduced.

  The work vehicle of the present invention includes a rear axle case supported by left and right rear wheels as the left and right traveling units, and a rear input shaft to which the engine power is transmitted and the rear input in the rear axle case. A laterally long rear drive shaft that branches the shaft power and transmits it to the left and right rear wheels, and the left and right main connection members, the sub-connection members, and the speed reduction mechanism are disposed on the rear drive shaft. By doing so, the main connecting member, the sub-connecting member, and the speed reduction mechanism can be compactly arranged on the same axis in the rear axle case, and it is greatly reduced from the configuration not including the sub-connecting member and the speed reduction mechanism. The sub-joining member and the speed reduction mechanism can be arranged without changing. In addition, since the main connecting member, the sub connecting member and the speed reduction mechanism can be arranged in a compact manner in the rear axle case, the main connecting member, the sub connecting member, and the main connecting member, without significantly increasing the size and weight of the rear axle case. A deceleration mechanism can be arranged.

  In the work vehicle of the present invention, the main connection member is disposed on the left and right inner sides of the rear drive shaft, and the sub-connection member and the speed reduction mechanism are disposed on the left and right outer sides of the rear drive shaft with respect to the main connection member. If the transmission torque capacity of the auxiliary connecting member is set to be smaller than that of the main connecting member, even if the axle is locked during the deceleration of the traveling part inside the turn, The drive system can be protected by sliding the member. In addition, even if both the main connection member and the sub-connection member are connected at the same time due to incorrect adjustment, for example, the main connection member is protected by sliding the sub-connection member having a small transmission torque capacity. The Also, by arranging the sub-joining member on the left and right outside of the main joint member, when the sub-joining member needs to be repaired or replaced due to failure or deterioration of the sub-joining member, the sub-joining member Can be easily removed, and the workability of repair and replacement of the sub-separating member is improved.

  In the work vehicle of the present invention, a single cam member that rotates left and right in conjunction with the steering operation of the steering operation tool, and a left and right main severing operation mechanism that severing the left and right main severing members. And a left and right sub-severing operation mechanism for performing a joint operation on the left and right sub-severing members, provided in the rear axle case, and a shut-off operation of the main joint operating mechanism with respect to the traveling part inside the turning, and a turning inside If the configuration is such that both the connection operation of the sub-connection operation mechanism with respect to the traveling portion is executed by the left and right rotation of the cam member, the main connection operation mechanism with a small number of parts The operation of the sub-joining operation mechanism can be realized, and the on / off timing of the main joint member and the sub-joining member can be accurately realized with a single cam member. In addition, the number of additional parts can be reduced as compared with the conventional configuration that does not include the sub-joining member and the sub-joining operation mechanism, and a significant increase in manufacturing cost of the work vehicle can be suppressed.

  In the work vehicle of the present invention, the cam member and the left and right cams may be connected to the cam member so that the main connecting member for the traveling portion inside the turning is in a power cut-off state and the sub-connecting member for the traveling portion inside the turning is connected. If the main severing operation mechanism and the left and right sub severing operation mechanisms are associated with each other, both the main severing member and the sub severing member are simultaneously connected to the traveling part inside the turn. Can be prevented, damage to the main joint member and the sub-joint member can be prevented, and deterioration of the main joint member and the sub-joint member can be reduced to increase the life.

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 drive system figure of a riding type rice transplanter. It is a hydraulic circuit diagram of a riding type rice transplanter. It is a top sectional view of a rear axle case. It is a top sectional view of a rear axle case. It is a drive system figure which shows the transmission mechanism to a rear wheel. It is a top view which shows rotation of the action arm at the time of left turn. It is a top view which shows rotation of the action arm at the time of right turn. It is a drive system figure which shows the transmission mechanism to the rear wheel in other embodiment. It is a drive system figure which shows the transmission mechanism to the rear wheel in other embodiment. It is a drive system figure which shows the transmission mechanism to the rear wheel in other embodiment. It is a drive system figure which shows the transmission mechanism to the rear wheel in other embodiment. It is a drive system figure which shows the transmission mechanism to the rear wheel in other embodiment. It is a drive system figure which shows the transmission mechanism to the rear wheel in other embodiment. It is a drive system figure which shows the transmission mechanism to the rear wheel in other embodiment. It is a drive system figure which shows the transmission mechanism to the rear wheel in other embodiment.

  Hereinafter, an embodiment embodying the present invention will be described with reference to the drawings in the case where the embodiment is applied to an eight-row planting type 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. 1-4. 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.

  A driving handle 14, a traveling main speed change lever (not shown), and a work lever 16 as a lifting operation tool are provided on the driving operation unit 13 on the rear upper surface side of the front bonnet 11. A steering seat 18 is disposed behind the front bonnet 11 on the upper surface of the work step 10 via a seat frame 17. 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 an 8-strip 4 connected to the planting input case 26. A set (one set of two) of planting transmission cases 27, a seedling planting mechanism 28 provided on the rear end side of each planting transmission case 27, a seedling mounting base 29 for eight-row planting, and each planting And a float 32 for surface flattening disposed on the lower surface side of the transmission case 27. The seedling planting mechanism 28 is provided with a rotary case 31 having two planting claws 30 for one line. Two planted 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. 5).

  A line marker 33 is provided on the left and right outside of the seedling planting device 23. The line marker 33 includes a marker ring body 34 for muscle pulling, and a marker arm 35 that rotatably supports the marker ring body 34. 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 line marker 33 is based on the operation of the operation lever 16 in the driving operation unit 13 and the work posture formed by landing on the surface as a reference trajectory in the next process, and the marker ring body 34 is lifted away from 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 ends of the two 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 frame 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.

  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 82 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 82.

  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 sub-transmission mechanism 42 by branching in the two directions of the front and rear wheels 3 and 4 and the seedling planting device 23.

  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, the pair of left and right side clutches 48, and the gear-type transmission 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 side 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 rear wheel 4 outside the turning to which power is transmitted rotates. It turns by driving.

  A rotor drive unit 86 having a leveling clutch 88 for power transmission to the leveling rotor 85 is provided in the rear axle case 9. 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 rotor 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 23 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, and the planting input case 26. 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 92 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 branches 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 moves 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 39. 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.

  As shown in FIGS. 7 to 9, 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. Is transmitted to the rear wheel 4 via the left and right gear-type transmission mechanism 49 and the rear axle 37, side clutches (main connection members) 48 respectively disposed on the left and right sides of the rear drive shaft 47, and the side clutch Leveling drive in which the power of the rear input shaft 242 is branched and transmitted to the four-wheel-drive turning clutch (sub-joining member) 111 and the speed reduction mechanism 131 disposed on the left and right sides of the rear drive shaft 47 on the left and right outer sides than 48. And a rotor drive unit 86 having a shaft 243 and a leveling clutch 88.

  The side clutch 48 has a structure in which the friction plates 151 and the steel plates 152 are alternately arranged, the steel plates 152 are fixed to the side clutch case 121, and the friction plates 151 are fixed to the rear drive shaft 47. The four-wheel drive clutch 111 has a structure in which a friction plate 161 and a steel plate 162 are alternately arranged. The friction plate 161 is fixed to an internal gear 134 of a speed reduction mechanism 131 (to be described later), and the rear axle case lid 244 is steel. The plate 152 is fixed so as to be slidable in the left-right direction. 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 leveling drive shaft 243 is connected to 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). In the rear axle case cover 244, a gear type transmission mechanism 49, a four-wheel drive turning clutch 111, and a speed reduction mechanism 131 are arranged. The gear transmission mechanism 49 transmits the power of the rear drive shaft 47 to the rear axle 37. A detachable lid member 247 is provided on the left and right outer sides of the rear axle case lid 244 at a position facing the four-wheel-drive turning clutch 111 in the left-right direction.

  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. 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, a rear drive shaft bevel gear 255 that transmits power to the rear drive shaft 47, and a leveling drive shaft that transmits power to the leveling drive shaft 243. A flat gear 256 is provided.

  The rear drive shaft bevel gear 255 and the leveling drive shaft flat gear 256 are provided on the rear end side of the rear input shaft 242. 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.

  As shown in FIGS. 8 and 9, side clutches 48 are provided on the left and right end sides of the rear drive shaft 47. A side clutch operating member 259 and a side clutch camshaft 261 for turning on and off the side clutch 48 are arranged inside the left and right sides of each side clutch 48. The side clutch 48 has a multi-plate structure and is configured to be turned off when the steering handle 14 is steered beyond a predetermined steering angle. When the side clutch 48 is connected, the rotational driving force of the rear drive shaft 47 is transmitted to the gear transmission mechanism 49 via the side clutch 48 and the reduction gear 122. The side clutch operating member 259 is slidably supported on the rear drive shaft 47, and the lower side cam surface of the side clutch cam shaft 261 is in contact with the left and right inner sides of the side clutch operating member 259.

  Further, on the left and right sides of the rear drive shaft 47 on the left and right sides of the side clutch 48, a four-wheel drive clutch 111 having a multi-plate structure and a planetary gear type speed reduction mechanism 131 are provided in order from the outside. The reduction mechanism 131 includes a sun gear 132 fixed to the rear drive shaft 47, an internal gear 134 connected to the sun gear 132 via a planetary gear 133, and a carrier 135 that supports the planetary gear 133 and is fixed to the reduction gear 122. Have A four-wheel drive turning operation member 113 and a four-wheel drive turning camshaft 112 are disposed on the left and right outer sides of each of the four-wheel drive turning clutch 111 to operate the four-wheel drive turning clutch 111 on and off. The four-wheel-drive turning clutch 111 is configured to be turned on when the steering handle 14 is turned more than a predetermined steering angle. The reduction mechanism 131 reduces the rotational driving force of the rear drive shaft 47 and transmits it to the gear transmission mechanism 49 when the four-wheel drive clutch 111 is engaged. The four-wheel drive turning operation member 113 is supported by the rear axle case lid 244 so as to be slidable in the axial direction of the rear drive shaft 47, and on the left and right outer sides of the four-wheel drive turning operation member 113, the lower end side of the four-wheel drive turning cam shaft 112. The cam surface is abutted.

  In this embodiment, the left and right side clutches 48, the four-wheel drive turning clutch 111, and the speed reduction mechanism 131 are disposed on the rear drive shaft 47. Therefore, the side clutch 48, the four-wheel drive turning clutch 111, and the speed reduction mechanism 131 are connected to the rear axle. The case 9 can be compactly arranged on the same axis, and the four-wheel drive turning clutch 111 and the speed reduction mechanism 131 can be arranged without significant changes from the configuration that does not include the four-wheel drive turning clutch 111 and the speed reduction mechanism 131. . Further, since the side clutch 48, the four-wheel-turning clutch 111, and the speed reduction mechanism 131 can be compactly arranged in the rear axle case 9, the size and weight of the rear axle case 9 are not significantly increased.

  Next, on / off operation of the side clutch 48 and the four-wheel drive clutch 111 will be described. As shown in FIGS. 3 and 4, the front end side of the intermediate rod 264 extending in the front-rear direction is connected to a steering arm 263 attached to the lower end portion of the steering output shaft 262 projecting downward from the lower surface of the power steering unit 66. . The rear end side of the intermediate rod 264 is connected to one end side of a rotating arm 265 disposed on the lower surface side of the rear axle case 9. The intermediate rod 264 is configured to push and pull back and forth in conjunction with the rotation of the steering output shaft 262.

  As shown also in FIG. 7, the other end side of the rotation arm 265 is fixed to the lower end side of the relay fulcrum shaft 266 that penetrates the rear axle case 9 vertically. The upper end side of the relay fulcrum shaft 266 is fixed to an operating arm (cam member) 267 disposed on the upper surface side of the rear axle case 9. The rotation arm 265, the relay fulcrum shaft 266, and the operation arm 267 rotate integrally around the relay fulcrum shaft 266. When the steering handle 14 is steered, the intermediate rod 264 is pushed and pulled in the front-rear direction in conjunction with this, and the operating arm 267 is rotated about the relay fulcrum shaft 266 together with the rotating arm 265.

  The actuating arm 267 includes a lateral clutch operating arm 267a that is horizontally long to which the upper end side of the relay fulcrum shaft 266 is fixed, a substantially U-shaped plate-like actuating arm 267b that is bolted to the side clutch actuating arm 267a, The left and right ends of the four-turn turning operation arm 267b have a pair of left and right four-turn turning operation cams 267c. The left and right end portions of the side clutch operating arm 267a are disposed so as to be able to contact and separate from a roller 268a provided on the tip side of the pair of left and right side clutch operating arms 268. The base end side of each side clutch operation arm 268 is fixed to a protruding end portion of the side clutch cam shaft 261 that protrudes upward from the upper surface of the rear axle case 9 (main body case portion 9c). The side clutch camshaft 261 and the side clutch operation arm 268 constitute a side clutch operation mechanism (main connection operation mechanism) 260.

  The pair of left and right four-wheel drive actuating cams 267c are arranged so as to be able to contact and separate from a roller 269a provided on the base end side of the pair of left and right four-wheel drive turning intermediate operation arms 269. A base end portion of the intermediate operation arm 269 for turning the four-wheel drive is pivotally supported on an arm bracket 270 fixed to the front surface of the rear axle case 9 through a vertically long pin member 269b.

  One end side of the four-wheel drive turning operation wire 272 is connected to the distal end side of the four-wheel drive turning intermediate operation arm 269 via a wire connecting piece 271. The other end side of the four-wheel drive operation wire 272 is connected to the distal end side of a left and right laterally long four-wheel drive operation arm 275 provided on the upper surface of the rear axle case lid 244 via a wire connecting piece 273 and a spring 274. ing. The base end side of each four-wheel drive turning operation arm 275 is fixed to a protruding end portion of the four-wheel drive turning cam shaft 112 protruding upward from the upper surface of the rear axle case lid 244 of the rear axle case 9. The 4WD turning camshaft 112, the 4WD turning intermediate operation arm 269, the wire connecting pieces 271, 273, the 4WD turning operation wire 272, the spring 274, and the 4WD turning operation arm 275 are included in the 4WD turning operation mechanism ( Sub-seating operation mechanism) 280 is configured.

  The operating arm 267 is rotated around the relay fulcrum shaft 266 so that the side clutch operating arm 268 is not in contact with any side clutch operating arm 267a, or the side clutch operating arm 267a is one of the side clutches. The operating arm 268 is displaced to a position where it is pressed. The lower clutch side cam surface of the side clutch cam shaft 261 fixed to the base end side of each side clutch operation arm 268 is brought into contact with the side clutch operation member 259. The side clutch operating member 259 is slid on the rear drive shaft 47 by the rotation of the side clutch cam shaft 261, and the side clutch 48 is turned on and off.

  Further, the operating arm 267 is rotated about the relay fulcrum shaft 266, and then the side clutch operating arm 267a contacts the roller 268a of one side clutch operating arm 268 and then further rotated in the same direction. The four-wheel turning operation cam 267c positioned diagonally with respect to the contact portion between the clutch operation arm 267a and the roller 268a presses the roller 269a of the four-wheel turning intermediate operation arm 269, and the four-wheel turning intermediate operation arm 269. Rotate horizontally. As the four-wheel turning intermediate operation arm 269 rotates, the four-wheel drive turning operation wire 272 is pulled, and the four-wheel turning operation wire 272, the four-wheel drive turning operation wire 272, the wire connection piece 273, and the spring 274 are passed through the four wheels. The 4WD turning operation arm 275 connected to the turning intermediate operation arm 269 rotates. The base end side of each four-wheel drive turning operation arm 275 is fixed to the upper end side of the four-wheel drive turning camshaft 112, and the lower end side cam surface of the four-wheel drive turning camshaft 112 is set to the left and right of the four-wheel drive turning clutch 111. It is in contact with the outside. The 4WD turning clutch 111 is turned on and off by the rotation of the 4WD turning camshaft 112.

  As described above, both the disconnection operation of the side clutch operation mechanism 260 and the connection operation of the four-wheel-drive turning operation mechanism 280 are configured to be executed by the left-right rotation of the operation arm 267. As a result, the operation of the side clutch operation mechanism 260 and the four-wheel-drive turning operation mechanism 280 can be realized with a small number of parts, and the on / off timing of the side clutch 48 and the four-wheel-drive turning clutch 111 can be accurately controlled with a single operating arm 267. realizable.

  In addition, the transmission torque capacity of the four-wheel drive clutch 111 is set smaller than that of the side clutch 48. Thereby, when the rear wheel 4 on the inside of the turn is decelerated, the drive system can be protected by sliding the four-wheel drive turning clutch 111 even if the rear axle 37 is locked. Further, even if both the side clutch 48 and the four-wheel drive turning clutch 111 are simultaneously connected due to, for example, misadjustment, the side clutch 48 is moved by the sliding of the four-wheel drive turning clutch 111 having a small transmission torque capacity. Protected. Further, when the four-wheel drive clutch 111 is arranged on the left and right outside of the side clutch 48, when the four-wheel drive clutch 111 needs to be repaired or replaced due to a failure or deterioration of the four-wheel drive clutch 111. The 4WD turning clutch 111 can be easily detached, and the workability of repairing and replacing the 4WD turning clutch 111 is improved. Further, since a detachable lid member 247 is provided on the left and right outer sides of the rear axle case lid 244 at a position facing the four-wheel-drive turning clutch 111 in the left-right direction. The turning clutch 111 can be easily removed.

  Further, both left and right end portions of the side clutch operating arm 267a are formed as arcuate surfaces around the relay fulcrum shaft 266, and the side clutch operating arm 267a rotates horizontally around the relay fulcrum shaft 266 to cause the side clutch operating arm 267a. After the roller 268a of the side clutch operation arm 268 comes into contact, the side clutch operation arm 268 is kept at a constant rotation position so that the amount of disengagement operation of the side clutch 48 is kept constant. Further, the contact portion of the four-wheel turning operation cam 267c with the roller 269a is formed in an arc surface centered on the relay fulcrum shaft 266, and the four-wheel turning operation cam 267c rotates horizontally around the relay fulcrum shaft 266. After the four-wheel turning operation cam 267c comes into contact with the roller 269a of the four-wheel turning intermediate operation arm 269, the four-wheel turning clutch 111 is engaged while keeping the four-wheel turning intermediate operation arm 269 at a fixed turning position. The operation amount is held constant. Further, the overstroke of the operation arms 269 and 275 is absorbed by the spring 274 such as a tension coil spring, so that an excessive load is not applied to the operation arms 269 and 275, the wire connecting pieces 271, 273, the operation wire 272, the cam shaft 112, and the like. I am doing so. Thereby, deformation and breakage of each member of the four-wheel-drive turning operation mechanism 280 are prevented.

  For example, when the steering handle 14 (see FIGS. 1 and 2) is steered to the left (counterclockwise) beyond a predetermined steering angle in order to change the direction on a headland in an agricultural field, the intermediate rod 264 is pulled. The operating arm 267 rotates counterclockwise in plan view via the rotating arm 265 and the relay fulcrum shaft 266, and the left end portion of the side clutch operating arm 267a of the operating arm 267 is turned inside as shown in FIG. The roller 268a of the (left side) side clutch operation arm 268 is pressed. When the left side clutch operating arm 268 is pressed, the left side clutch cam shaft 261 rotates and the left side clutch operating member 259 is displaced to the left side, and the side clutch 48 on the inner side (left side) is turned off. Operate. After the left side clutch 48 is disengaged, the right-hand four-turn turning operation cam 267c of the operating arm 267 presses the roller 269a of the right-hand four-turn turning intermediate operation arm 269, and the four-turn turning intermediate operation is performed. The left 4WD turning operation wire 272 connected to the tip of the arm 269 is pulled, and the left 4WD turning operation arm 275 is rotated. Along with this, the left four-wheel drive cam shaft 112 is rotated and the four-wheel drive operation member 113 is displaced to the right, and the four-wheel drive clutch 111 on the inner side (left side) is turned on and operated. The side clutch 48 on the outer side (right side) of the turning is in a connected state (on state), and the four-wheel drive turning clutch 111 on the outer side (right side) of the turning is in a released state (disengaged state).

  Further, when the steering handle 14 is steered rightward (clockwise) beyond a predetermined steering angle, the intermediate rod 264 is pushed, and the operating arm 267 is viewed in plan view via the rotating arm 265 and the relay fulcrum shaft 266. As shown in FIG. 11, the right end of the side clutch operating arm 267a of the operating arm 267 presses the roller 268a of the side clutch operating arm 268 on the inner side of the turning (right side), and the inner side of the turning (right side). The side clutch 48 is turned off. After the right side clutch 48 is in the disconnected state, the left four-wheel drive turning operation cam 267c of the operation arm 267 presses the roller 269a of the left four-wheel drive intermediate operation arm 269, and the right four-wheel drive turning The operation wire 272 is pulled, and the right four-wheel drive operation arm 275 rotates. Along with this, the right-hand four-wheel drive camshaft 112 rotates, and the four-wheel drive clutch 111 on the inner side (right side) turns on and operates. The side clutch 48 on the outer side (left side) of the turning is in the connected state, and the four-wheel drive turning clutch 111 on the outer side (left side) of the turning is in the released state.

  When the steering handle 14 is less than a predetermined steering angle, the left and right side clutches 48 are in a connected state, and the left and right four-wheel drive clutch 111 are in a released state. At this time, the rear drive shaft 47 is connected to the reduction gear 122 rotatably supported by the rear drive shaft 47 via the side clutch 48. Here, the side clutch cover 121 of the side clutch 48 is fixed to the reduction gear 122, and the rear drive shaft 47 is connected to the intermediate shaft 124 via the side clutch 48, the reduction gear 122, and the intermediate gear 123. The intermediate shaft 124 is connected to the rear axle 37 via the intermediate shaft gear 125 and the final gear 126. The rotational driving force of the rear drive shaft 47 is decelerated by the reduction gear 122 and the intermediate gear 123, and the intermediate shaft gear 125 and the final gear 126, respectively, and transmitted to the rear axle 37. In the planetary gear type reduction mechanism 131, the sun gear 132 fixed to the rear drive shaft 47 and the carrier 135 fixed to the side clutch case 121 via the reduction gear 122 have the same rotation direction and rotation speed. Therefore, the planetary gear 133 supported by the carrier 135 does not rotate. Further, since the four-wheel drive clutch 111 is in the released state, the internal gear 134 is not fixed. Therefore, the speed reduction mechanism 131 rotates integrally with the rear drive shaft 47, the side clutch 48, and the speed reduction gear 122 in the same rotational direction and rotational speed.

  When the steering handle 14 is equal to or greater than a predetermined steering angle, the side clutch 48 inside the turning is in a disconnected state (disengaged state), the four-wheel turning clutch 111 inside the turning is in a connected state, and the rear drive shaft 47 is inside the turning. It is connected to a reduction gear 122 on the inside of the turn through a reduction mechanism 131. When the four-wheel drive clutch 111 is in the connected state, the internal gear 134 that is rotatably supported by the rear drive shaft 47 is fixed to the rear axle case 244. As the sun gear 132 fixed to the rear drive shaft 47 rotates, the planetary gear 133 revolves while rotating, and the carrier 135 that pivotally supports the planetary gear 133 rotates in the same direction as the rotation of the sun gear 132. As a result, the rear drive shaft 47 is connected to the reduction gear 122 via the sun gear 132, the planetary gear 133 and the carrier 135. The rotational driving force of the rear drive shaft 47 is decelerated by the reduction mechanism 131, the reduction gear 122 and the intermediate gear 123, the intermediate shaft gear 125 and the final gear 126, and transmitted to the rear axle 37. The side clutch case 121 fixed to the reduction gear 122 rotates in the same rotational direction as the rear drive shaft 47 at a lower rotational speed than the rear drive shaft 47. In this embodiment, the speed reduction ratio of the speed reduction mechanism 131 is set to a speed reduction ratio at which the rear wheel 4 inside the turn hardly slips when turning when the steering handle 14 is equal to or greater than a predetermined steering angle. For example, if the number of teeth of the sun gear 132 and the planetary gear 133 is the same, the reduction ratio of the reduction mechanism 131 becomes ¼.

  As described above, when the steering handle 14 is equal to or larger than the predetermined steering angle, the four-wheel turning clutch 111 on the inner side of the turning is connected and operated on the rear wheel 4 on the inner side of the turning with the disconnection operation of the side clutch 48 on the inner side of the turning. Driving power drives the rear wheel 4 inside the turn at a lower speed than the rear wheel 4 outside the turn via the speed reduction mechanism 131. As a result, the turning performance of the rice transplanter 1 is improved, the vehicle can always turn by four-wheel drive, and the traveling part inside the turning does not rotate and changes the direction on the spot to eliminate the state of digging the ground. It is possible to reduce the state in which the rear wheel 4 makes the field rough when turning. Moreover, since it always turns by four-wheel drive, sinking of the rice transplanter 1 can be reduced. Note that when the steering handle 14 is steered to less than a predetermined steering angle, the side clutch 48 is held in a power connection state both inside and outside the turning. For this reason, it is possible to prevent a large meandering traveling by the steering operation of the steering handle 14, and the alignment steering performance (straight traveling performance) is high.

  In the embodiment, when the steering handle 14 is steered to a predetermined steering angle or more, the side clutch 48 on the inner side of the turning is in a power cut-off state, and at the same time, the four-turn turning clutch 111 on the inner side of the turning is engaged (connected). Further, the operation arm 267, the left and right side clutch operation mechanisms 260, and the left and right four-wheel drive operation mechanisms 280 are related. As a result, it is possible to prevent both the side clutch 48 and the four-wheel drive turning clutch 111 with respect to the rear wheel 4 inside the turn from being simultaneously engaged (connected state), and damage to the side clutch 48 and the four-wheel drive turning clutch 111 is prevented. Can be prevented. Further, the deterioration of the side clutch 48 and the four-wheel drive clutch 111 can be reduced, and the life can be extended.

  FIG. 12 is a drive system diagram showing a transmission mechanism to the rear wheels in another embodiment. In this embodiment, as compared with the above-described embodiment shown in FIG. 9, the reduction gear 122 is arranged on the left and right outside of the four-wheel drive clutch 111 and the reduction mechanism 131, and the intermediate gear 123 that meshes with the reduction gear 122. Is arranged on the left and right outside of the intermediate shaft gear 125. The side clutch case 121 of the side clutch 48 is fixed to the internal gear 134 of the speed reduction mechanism 131.

  When the steering handle 14 is less than the predetermined steering angle, the side clutch 48 is in the connected state, and the four-wheel drive turning clutch 111 is in the released state, and the rotational driving force of the rear drive shaft 47 is the deceleration that rotates together with the side clutch 48. It is transmitted to the reduction gear 122 via the mechanism 131. Since the sun gear 132 and the internal gear 134 have the same rotation direction and rotation speed, the planetary gear 133 does not rotate, and the speed reduction mechanism 131 rotates integrally and does not exhibit the speed reduction function. Since the four-wheel drive clutch 111 is in the released state, the internal gear 134 is not fixed. Therefore, the rear drive shaft 47, the side clutch 48, the reduction gear 122, and the reduction mechanism 131 rotate at the same rotation direction and rotation speed.

  When the steering handle 14 is equal to or greater than a predetermined steering angle, the side clutch 48 on the inside of the turn is in a disconnected state, the four-wheel turning clutch 111 on the inside of the turn is in a connected state, and the rear drive shaft 47 connects the speed reducing mechanism 131 on the inside of the turn. To the reduction gear 122 inside the turn. The internal gear 134 is fixed to the rear axle case 244 by the connection operation of the four-wheel-turning clutch 111, and the planetary gear 133 revolves while rotating as the sun gear 132 fixed to the rear drive shaft 47 rotates. Is rotated in the same direction as the rotation of the sun gear 132. As a result, the rear drive shaft 47 is connected to the reduction gear 122 via the sun gear 132, the planetary gear 133 and the carrier 135. Then, the rotational driving force of the rear drive shaft 47 is decelerated by the reduction mechanism 131 and transmitted to the reduction gear 122. Since the side clutch case 121 is fixed to the rear axle case 244 via the internal gear 134 and the four-wheel drive clutch 111, it does not rotate.

  The four-wheel drive clutch 111 in the embodiment is not limited to a multi-plate structure, and may be an engagement clutch 141 (see FIG. 13) such as a dog clutch, for example. In place of the four-wheel drive clutch 111, an inward-expanding drum brake 142 (see FIG. 14) for pressing the friction material on the inner periphery of the cylinder and a band brake 143 (FIG. 15) for tightening the outer periphery of the cylinder with the friction material are arranged. May be. The bite clutch 141, the drum brake 142, and the band brake 143 fix the internal gear 134 to the rear axle case lid 244 during connection operation. The operation of the bite clutch 141, the drum brake 142, and the band brake 143 is operated by the rotation of the four-wheel drive operation arm 275 (see FIG. 7). Further, the transmission torque capacity (braking torque capacity) of the bite clutch 141, the drum brake 142 and the band brake 143 is preferably smaller than that of the side clutch 48. A similar configuration can be applied to the above-described embodiment shown in FIG.

  FIG. 16 is a drive system diagram showing a transmission mechanism to a rear wheel in still another embodiment. In this embodiment, as compared with the above-described embodiment shown in FIG. 12, the side clutch case 121 and the four-wheel-drive swivel are turned by displacing the side clutch case 121 of the side clutch 48 by the rotation of the cam shaft 261 for the side clutch. The clutch 111 is configured to be turned on and off with a single side clutch cam shaft 261. By an elastic member (not shown) arranged in the side clutch 48, the side clutch case 121 is pushed inward in the left and right directions, the steel plate 152 is pushed by the friction plate 151, and the side clutch 48 is brought into a connected state. As the side clutch cam shaft 261 rotates, the side clutch case 121 is pressed to the left and right outside via the side clutch operating member 259, the steel plate 152 slides to the left and right outside, and the side clutch 48 is in the disconnected state.

  An internal gear 134 of the speed reduction mechanism 131 is fixed to the side clutch case 121. The internal gear 134 is fixed with the friction plate 161 of the four-wheel drive clutch 111. The steel plate 152 of the four-wheel-drive turning clutch 111 is fixed to the wheel shaft case cover 244. When the side clutch 48 is in the connected state, the friction plate 161 is not pressed against the steel plate 152 and the four-wheel drive clutch 111 is in the released state, while the side clutch 48 is in the disconnected state and at the same time the friction plate 161 is in the steel plate 152. When pressed, the four-wheel drive clutch 111 is configured to be in a connected state.

  In this embodiment, since the on / off operation of the side clutch 48 and the four-wheel-drive turning clutch 111 is performed by the single side clutch cam shaft 261, the on / off timing of both the clutches 48 and 111 can be realized with high accuracy. Also, a four-wheel drive operation mechanism 280 (four-wheel drive cam shaft 112, four-wheel drive intermediate operation arm 269, wire connecting pieces 271, 273, four-wheel drive operation wire 272, spring 274, and four-wheel drive operation. The arm 275) and the arm bracket 270 are not required, and the four-turn turning operation arm 267b and the four-turn turning operation cam 267c of the operation arm 267 are not required, so that both clutches 48 and 111 can be operated with a small number of parts. This can be realized, and the increase in manufacturing cost due to the additional mounting of the four-wheel drive clutch 111 and the speed reduction mechanism 131 can be reduced.

  FIG. 17 is a drive system diagram showing a transmission mechanism to a rear wheel in still another embodiment. In this embodiment, the four-wheel drive clutch 111 and the speed reduction mechanism 131 are disposed on the left and right inner sides of the reduction gear 122 and the side clutch 48, and the side clutch 48 is disposed on the left and right outer sides of the speed reduction gear 122. The reduction gear 122 is fixed to the side clutch case 121 of the side clutch 48 and the carrier 135 of the reduction mechanism 131. The internal gear 134 of the speed reduction mechanism 131 is fixed to the rear axle case 9 or the rear axle case 244. The sun gear 132 is fixed to the 4WD turning clutch case 114 of the 4WD turning clutch 111. The sun gear 132 and the four-wheel drive clutch case 114 are rotatably supported by the rear drive shaft 47. The friction plate 161 of the four-wheel drive clutch 111 is supported by the rear drive shaft 47 so as to be slidable in the axial direction of the rear drive shaft 47 and to rotate together with the rear drive shaft 47.

  When the steering handle 14 is less than a predetermined steering angle, the side clutch 48 is in a connected state, and the four-wheel drive clutch 111 is in a released state, and the rotational driving force of the rear drive shaft 47 is reduced via the side clutch 48. 122. On the other hand, when the steering handle 14 is equal to or larger than the predetermined steering angle, the side clutch 48 inside the turning is in a disconnected state, the four-wheel turning clutch 111 inside the turning is in a connected state, and the rear drive shaft 47 is connected to the four-wheel drive inside the turning. It is connected to the reduction gear 122 inside the turning through the turning clutch 111 and the speed reduction mechanism 131. Due to the connection operation of the four-wheel-turning clutch 111, the sun gear 132 is coupled to the rear drive shaft 47 via the four-wheel-turning clutch 111, and the planetary gear 133 rotates and revolves as the sun gear 132 rotates. Is rotated in the same direction as the rotation of the sun gear 132. Thereby, the rotational driving force of the rear drive shaft 47 is decelerated by the reduction mechanism 131 and transmitted to the reduction gear 122 via the four-wheel drive clutch 111, the sun gear 132, the planetary gear 133, and the carrier 135. Since the side clutch case 121 is fixed to the reduction gear 122, the side clutch case 121 rotates in the same rotational direction as the rear drive shaft 47 at a lower rotational speed than the rear drive shaft 47.

  Referring to FIG. 7 as well, the upper end portion of the side clutch cam shaft 261 disposed on the left and right outer sides of the side clutch 48 is connected to the operation arm 275, and the four-wheel turning clutch 111 is used for four-wheel turning. The upper end portion of the cam shaft 112 is connected to the operation arm 268. In this case, the side clutch 48 is connected / disconnected by the operation mechanism 280, and the four-wheel drive clutch 111 is connected / disconnected by the operation mechanism 260. When the members of both the operating mechanisms 260 and 280 and the operating arm 267 are adjusted in position or changed in shape and the steering handle 14 is steered to a predetermined steering angle or more, the side clutch 48 is cut off and the side clutch is operated. Both operating mechanisms 260 and 280 and the operating arm 267 are related so that the four-wheel-drive turning clutch 111 is connected and operated at the same time when the 48 is in the disconnected state.

  In this embodiment, the power toward the rear wheel 4 inside the turn is obtained by connecting and operating the four-wheel turning clutch 111 for the rear wheel 4 inside the turn along with the disconnection operation of the side clutch 48 on the rear wheel 4 inside the turn. However, the rear wheel 4 inside the turn is driven at a lower speed than the rear wheel 4 outside the turn via the four-wheel drive turning clutch 111 and the speed reduction mechanism 131. Accordingly, the vehicle can always turn by four-wheel drive, and the rear wheel 4 inside the turn does not rotate but changes its direction on the spot to eliminate the state of digging the ground, and the rear wheel 4 inside the turn makes the work area rough when turning. The state can be reduced.

  The configuration of this embodiment in which the power toward the rear wheel 4 inside the turn passes through the four-wheel drive turning clutch 111 and the speed reduction mechanism 131 is applied to each embodiment shown in FIGS. 9 and 12 to 16. it can. Further, in each embodiment shown in FIGS. 9 and 12 to 16, the four-wheel drive clutch 111 may be arranged on the left and right inner sides of the side clutch 48.

  FIG. 18 is a drive system diagram showing a transmission mechanism to a rear wheel in still another embodiment. In this embodiment, a two-stage reduction mechanism 171 is arranged in place of the planetary gear type reduction mechanism 111 as compared with the above-described embodiment shown in FIG. The two-stage reduction mechanism 171 is provided in a first reduction drive gear 172 connected to the rear drive shaft 47, a two-stage planetary gear 174 having a first reduction driven gear 173 meshed with the first reduction drive gear 172, and a two-stage planetary gear 174. And a second reduction driven gear 176 that meshes with the second reduction drive gear 175 and loosely fits on the rear drive shaft 47, and a carrier 177 that supports the two-stage planetary gear 174 and loosely fits on the rear drive shaft 47. Second reduction driven gear 176 is fixed to reduction gear 122. The friction plate 161 of the four-wheel drive clutch 111 is coupled to the carrier 177 so as to rotate together with the carrier 177.

  When the steering handle 14 is less than the predetermined steering angle, the side clutch 48 is in a connected state, and the four-wheel drive turning clutch 111 is in a released state, and the rotational driving force of the rear drive shaft 47 is reduced through the side clutch 48. 122. In the two-stage reduction mechanism 171, the first reduction drive gear 172 fixed to the rear drive shaft 47 and the second reduction driven gear 176 fixed to the reduction gear 122 have the same rotation direction and rotation speed. The two-stage planetary gear 174 does not rotate. Further, since the four-wheel drive clutch 111 is in the released state, the carrier 177 is not fixed. Accordingly, the two-stage reduction mechanism 171 rotates integrally with the rear drive shaft 47, the side clutch 48, and the reduction gear 122 in the same rotation direction and rotation speed.

  When the steering handle 14 is equal to or greater than a predetermined steering angle, the side clutch 48 on the inside of the turn is in a disconnected state, the four-wheel turning clutch 111 on the inside of the turn is in a connected state, and the rear drive shaft 47 connects the speed reducing mechanism 131 on the inside of the turn. To the reduction gear 122 inside the turn. By the connection operation of the four-wheel drive clutch 111, the carrier 177 is fixed to the rear axle case 244 via the four-wheel drive clutch 111. As the first reduction drive gear 172 fixed to the rear drive shaft 47 rotates, the two-stage planetary gear 174 (the first reduction driven gear 173 and the second reduction drive gear 175) rotates opposite to the first reduction drive gear 172. Rotate in the direction. The second reduction drive gear 175 that meshes with the second reduction drive gear 175 and the reduction gear 122 fixed to the second reduction drive gear 175 rotate in the same rotational direction as the first reduction drive gear 172. The rotational driving force of the rear drive shaft 47 is decelerated by the two-stage reduction mechanism 171 and transmitted to the reduction gear 122. In this embodiment, the speed reduction ratio of the two-stage speed reduction mechanism 171 is set to a speed reduction ratio at which the rear wheel 4 inside the turn hardly slips when turning when the steering handle 14 has a predetermined steering angle or more. For example, if the reduction ratio of the first reduction driving gear 172 and the first reduction driven gear 173 and the reduction ratio of the second reduction driving gear 175 and the second reduction driven gear 176 are respectively 1/2, The speed reduction ratio of the speed reduction mechanism 171 is 1/4.

  In this embodiment, when the side clutch 48 inside the turning is disconnected, the four-wheel turning clutch 111 inside the turning is connected and operated so that the power toward the rear wheel 4 inside the turning passes through the two-stage reduction mechanism 171. Then, the rear wheel 4 inside the turn is driven at a lower speed than the rear wheel 4 outside the turn. Accordingly, the vehicle can always turn by four-wheel drive, and the rear wheel 4 inside the turn does not rotate but changes its direction on the spot to eliminate the state of digging the ground, and the rear wheel 4 inside the turn makes the work area rough when turning. The state can be reduced.

  FIG. 19 is a drive system diagram showing a transmission mechanism for a rear wheel in still another embodiment. In this embodiment, as compared with the above-described embodiment shown in FIG. 18, the reduction gear 122 is disposed on the left and right outer sides of the four-wheel drive clutch 111 and the two-stage reduction mechanism 171 and is intermediately engaged with the reduction gear 122. The gear 123 is disposed on the left and right outside of the intermediate shaft gear 125. Further, the side clutch case 121 of the side clutch 48 is fixed to the carrier 177 of the two-stage reduction mechanism 171.

  When the steering handle 14 is less than the predetermined steering angle, the side clutch 48 is in the connected state, and the four-wheel drive turning clutch 111 is in the released state, and the rotational driving force of the rear drive shaft 47 rotates together with the side clutch 48 2. This is transmitted to the reduction gear 122 via the step reduction mechanism 171. Since the first reduction drive gear 172 fixed to the rear drive shaft 47 and the carrier 177 connected to the rear drive shaft 47 via the side clutch 48 have the same rotational direction and rotational speed, the two-stage planetary gear 174 is The second reduction driven gear 176 that meshes with the second reduction drive gear 175 of the two-stage planetary gear 174 does not rotate and rotates at the same rotation direction and rotation speed as the carrier 177. Thus, the two-stage speed reduction mechanism 171 rotates integrally and does not exhibit a speed reduction function. Since the four-wheel-drive turning clutch 111 is in a released state, the carrier 177 is not fixed. Therefore, the rear drive shaft 47, the side clutch 48, the reduction gear 122, and the two-stage reduction mechanism 171 rotate at the same rotation direction and rotation speed.

  When the steering handle 14 is equal to or greater than the predetermined steering angle, the side clutch 48 inside the turn is in a disconnected state, the four-wheel drive turning clutch 111 inside the turn is in a connected state, and the rear drive shaft 47 is a two-stage reduction mechanism inside the turn. 171 is connected to the reduction gear 122 inside the turn. By the connection operation of the four-wheel drive clutch 111, the carrier 177 is fixed to the rear axle case 244 via the four-wheel drive clutch 111. As the first reduction drive gear 172 fixed to the rear drive shaft 47 rotates, the two-stage planetary gear 174 (the first reduction driven gear 173 and the second reduction drive gear 175) rotates opposite to the first reduction drive gear 172. Rotate in the direction. The second reduction drive gear 175 that meshes with the second reduction drive gear 175 and the reduction gear 122 fixed to the second reduction drive gear 175 rotate in the same rotational direction as the first reduction drive gear 172. The rotational driving force of the rear drive shaft 47 is decelerated by the two-stage reduction mechanism 171 and transmitted to the reduction gear 122. Since the side clutch case 121 is fixed to the rear axle case 244 via the carrier 177 and the four-wheel drive clutch 111, it does not rotate.

  In each embodiment shown in FIGS. 18 and 19, the four-wheel-drive turning clutch 111 includes an engagement clutch 141, an inwardly expanding drum brake 142, as in each embodiment shown in FIGS. 13 to 15. A band brake 143 or the like may be used. 18 and 19, it is preferable that the transmission torque capacity of the four-wheel drive clutch 111 is smaller than that of the side clutch 48. Note that the transmission torque capacity or braking torque capacity of the four-wheel-drive turning clutch 111, the meshing clutch 141, the inwardly expanding drum brake 142, and the band brake 143 may be the same as that of the side clutch 48, or the side clutch. It may be greater than 48. Further, the two-stage reduction mechanism 171 in each embodiment shown in FIGS. 18 and 19 can be applied to each embodiment shown in FIGS. 9 and 12 to 17.

  As described above, the rice transplanter 1 as an example of the working vehicle includes the traveling machine body 2 on which the engine 5 is mounted, the left and right rear wheels 4 (traveling unit) that support the traveling machine body 2, and the traveling machine body. 2, a steering handle 14 (steering operation tool) that changes the traveling direction of the steering wheel 14, and left and right side clutches 48 (main connection members) that relay power transmission to the left and right rear wheels 4. In response to the steering operation, the side clutch 48 for the rear wheel 4 inside the turn is cut off. In addition to the left and right side clutches 48, the rice transplanter 1 has a left and right four-wheel drive clutch 111, a meshing clutch 141, a drum brake 142 or a band brake 143 (sub-joining member, hereinafter referred to as a four-wheel drive swing clutch 111 and the like). And a speed reduction mechanism 131 or 171 (hereinafter referred to as speed reduction mechanism 131 or the like). Then, the rice transplanter 1 connects and operates the four-wheel drive clutch 111 and the like for the rear wheel 4 on the turning side in accordance with the disconnection operation of the side clutch 48 for the rear wheel 4 on the turning side. The power toward the vehicle passes through the speed reduction mechanism 131 and drives the rear wheel 4 inside the turn at a lower speed than the rear wheel 4 outside the turn. Accordingly, the vehicle can always turn by four-wheel drive, and the rear wheel 4 inside the turn does not rotate but changes its direction on the spot to eliminate the state of digging the ground, and the rear wheel 4 inside the turn makes the work area rough when turning. The state can be reduced. Moreover, since it always turns by four-wheel drive, for example, when a work place is a rice field, sinking of a work vehicle can be reduced.

  The rice transplanter 1 of the above embodiment includes a rear axle case 9 supported by the left and right rear wheels 4, and a rear input shaft 242 to which power of the engine 5 is transmitted and power of the rear input shaft are disposed in the rear axle case 9. The left and right side clutches 48, the four-wheel drive turning clutch 111, the reduction mechanism 131, and the like are disposed on the rear drive shaft 47. . As a result, the side clutch 48, the four-wheel drive turning clutch 111, etc., the speed reduction mechanism 131, etc. can be compactly arranged on the same axis in the rear axle case 9, and the four-wheel drive turning clutch 111, the speed reduction mechanism 131, etc. are provided. The four-wheel drive clutch 111 and the deceleration mechanism 131 and the like can be arranged without significant change from the configuration without the above. Further, since the side clutch 48, the four-wheel-turning clutch 111, etc. and the speed reduction mechanism 131, etc. can be compactly arranged in the rear axle case 9, the side clutch 48, without significantly increasing the size and weight of the rear axle case 9, The four-wheel drive clutch 111 and the like, the speed reduction mechanism 131 and the like can be arranged.

  In the rice transplanter 1 of the above-described embodiment, the side clutch 48 is disposed on the left and right inner sides of the rear drive shaft 47, and the four-wheel drive turning clutch 111 and the like and the speed reduction mechanism 131 and the like are disposed on the left and right outer sides of the rear drive shaft 47. And the transmission torque capacity of the four-wheel drive clutch 111 or the like is set smaller than that of the side clutch 48. Thus, when the rear wheel 4 on the inside of the turn is decelerated, the drive system can be protected by sliding the four-wheel drive turning clutch 111 and the like even if the rear axle 37 is locked. In addition, even if both the side clutch 48 and the four-wheel drive swing clutch 111 and the like are simultaneously connected due to misadjustment, for example, the four-wheel drive turn clutch 111 having a small transmission torque capacity slips and the side clutch 48 is protected. Further, by arranging the four-wheel drive clutch 111 and the like on the left and right outside of the side clutch 48, the four-wheel drive clutch 111 and the like need to be repaired or replaced due to failure or deterioration of the four-wheel drive clutch 111 or the like. When this happens, the 4WD turning clutch 111 and the like can be easily removed, and the workability of repairing and replacing the 4WD turning clutch 111 and the like is improved.

  The rice transplanter 1 of the above embodiment includes a single operating arm 267 (cam member) that rotates left and right in conjunction with the steering operation of the steering handle 14 and the left and right side clutches that perform the intermittent operation of the left and right side clutches 48. The rear axle case 9 is provided with an operation mechanism 260 (main connection operation mechanism) and a left and right four-wheel drive operation mechanism 280 (sub-connection operation mechanism) for connecting and disconnecting the left and right four-wheel drive clutch 111 and the like. Both the disconnection operation of the side clutch operation mechanism 260 with respect to the rear wheel 4 inside the turning and the connection operation of the operation mechanism 280 for four-wheel drive turning with respect to the rear wheel 4 inside the turning are executed by the left and right rotation of the operating arm 267. It is configured as follows. As a result, the operation of the side clutch operation mechanism 260 and the four-wheel-drive turning operation mechanism 280 can be realized with a small number of parts, and the on / off timing of the side clutch 48 and the four-wheel-drive turning clutch 111 can be accurately controlled with a single operating arm 267. realizable. In addition, the number of additional parts can be reduced compared to the conventional configuration that does not include the four-wheel drive turning clutch 111 and the like and the four-wheel drive turning operation mechanism 280, and a significant increase in the manufacturing cost of the rice transplanter 1 can be suppressed.

  In the rice transplanter 1 of the above embodiment, the operating arm 267 is operated so that the side clutch 48 for the rear wheel 4 inside the turn is in a power cut-off state and the four-wheel drive clutch 111 and the like for the rear wheel 4 inside the turn are connected. The left and right side clutch operating mechanisms 260 and the left and right four-wheel drive operating mechanisms 280 are associated with each other. As a result, it is possible to prevent both the side clutch 48 and the sub-engagement member from being connected to the rear wheel 4 inside the turn at the same time, and to prevent damage to the side clutch 48 and the four-wheel drive clutch 111 and the like. Deterioration of the clutch 48 and the four-wheel drive clutch 111 and the like can be reduced and the life can be extended.

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

1 Rice transplanter 2 Traveling machine body 4 Rear wheel (traveling part)
5 Engine 9 Rear axle case 14 Steering handle (steering control tool)
47 Rear drive shaft 48 Side clutch 111 Four-wheel drive clutch (sub-joining member)
131 Deceleration mechanism 141 Occlusal clutch (sub-joining member)
142 Drum brake (sub-joining member)
143 Band brake (sub-separating member)
260 Side clutch operation mechanism (main relay operation mechanism)
267 Actuating arm (cam member)
280 Four-wheel drive turning operation mechanism (sub-joining operation mechanism)

Claims (5)

A traveling machine body equipped with an engine, left and right traveling parts that support the traveling machine body, a steering operation tool that changes the traveling direction of the traveling machine body, and a left and right that interrupts power transmission to the left and right traveling parts A work vehicle that operates to cut off the main connection member with respect to the traveling part inside the turn according to the steering operation of the steering operation tool,
Separately from the left and right main connection members, the left and right sub-connection members and a speed reduction mechanism,
Along with the shut-off operation of the main connection member for the traveling part inside the turn, the sub-connection member is connected to the traveling part inside the turn so that the power toward the traveling part inside the turn is transmitted to the deceleration mechanism. Via, the driving part inside the turning is driven at a lower speed than the traveling part outside the turning,
Work vehicle. A rear axle case supported by left and right rear wheels as the left and right traveling parts;
The rear axle case includes a rear input shaft to which the power of the engine is transmitted, and a horizontally long rear drive shaft that branches the power of the rear input shaft and transmits the power to the left and right rear wheels.
The left and right main connection members, the sub-connection members and the speed reduction mechanism are disposed on the rear drive shaft,
The work vehicle according to claim 1. The main connection member is disposed on the left and right inner sides of the rear drive shaft, the sub-connection member and the speed reduction mechanism are disposed on the left and right outer sides of the main drive member on the rear drive shaft, and the sub-connection is performed. The transmission torque capacity of the member is set smaller than that of the main connection member,
The work vehicle according to claim 2. A single cam member that rotates to the left and right in conjunction with the steering operation of the steering operation tool, left and right main severing operation mechanisms that sever the left and right main severing members, and the left and right sub-joints. A left and right sub-severing operation mechanism for jointing the cutting member is provided in the rear axle case;
Both the shut-off operation of the main severing operation mechanism with respect to the traveling part inside the turn and the connection operation of the sub-severing operation mechanism with respect to the traveling part inside the turn are performed by turning the cam member left and right. Configured to,
The work vehicle according to claim 2. The cam member and the left and right main severing operation mechanisms so that the main severing member for the traveling part inside the turning is in a power cut-off state and the sub-severing member for the traveling part inside the slewing is connected and operated. And the left and right sub-severing operation mechanism,
The work vehicle according to claim 4.

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