JP6116469B2 - Work vehicle - Google Patents

Description

  The present invention includes a brake equipped in a transmission case, a brake operation shaft for operating the brake from outside the transmission case, and a brake pedal for operating the brake operation shaft. About.

As described above, as a work vehicle having a brake operation shaft for performing a brake operation from the outside of the mission case with respect to a brake installed in the mission case, the work vehicle described in [1] and [2] below is available. is there.
[1] The differential input gear provided in the transmission case is used as a brake disc, and it is sandwiched between the brake pads from the left and right by a cam mechanism operated by a brake pedal, and brakes are applied to the transmission shaft to the traveling system. Thing (refer patent document 1).
[2] A brake operation shaft is provided for sliding the operation member in the pressing direction against the friction plate provided on the outer periphery of the traveling output shaft in the transmission case, and the brake operation shaft is linked to the brake pedal. Thing (refer patent document 2).

JP 2002-347457 (paragraph [0025], FIG. 8) JP 2008-173087 A (paragraph [0032], FIG. 6)

In the work vehicle described in Patent Document 1 described above, the transmission shaft of the traveling system can be braked in accordance with the depression operation of the brake pedal. There is a need for disassembling the case, and there is room for improvement in this regard.
In other words, since the cam mechanism that presses the brake pad has a structure larger than the shaft diameter of the brake operation shaft in the transmission case, the brake operation shaft can be connected to the outside without disassembling the transmission case from the pivot hole of the brake operation shaft. The structure cannot be pulled out.

  In the work vehicle described in Patent Document 2, the operation member that presses the friction plate is provided on the travel output shaft side where the friction plate is provided, and the brake operation shaft that slides the operation member is the travel output shaft. Consists of separate axes. Thereby, the shaft diameter of the brake operation shaft can be formed to be equal to or smaller than the diameter of the pivot hole of the brake operation shaft. However, since the retaining means for restricting the brake operation shaft from being pulled out is formed on the transmission case wall located on the shaft end side of the brake operation shaft, it is desired to perform maintenance by removing the brake operation shaft. In some cases, there is also the trouble that the operation of disassembling the mission case is necessary, and there is room for improvement in this respect.

The present invention, without requiring a complicated work, such as to degrade the transmission case, Ru der intended to facilitate the maintenance work such as pulling out the brake operating shaft to the outside of the transmission case.

[Solution 1]
The technical means of the working machine in the present invention taken to solve the above problems includes a brake installed in a mission case, a brake operation shaft that performs a brake operation on the brake from the outside of the mission case, A brake pedal for operating the brake operating shaft, and a regulating member for regulating the escape of the brake operating shaft to the outside of the transmission case is provided outside the transmission case, and the regulating member is in a state where That is, it can be switched to a release state.

[Operation and effect of invention according to Solution 1]
According to the configuration of the present invention according to the above solution 1,
As the brake operating shaft can be reliably controlled by the regulating member, the regulating member is equipped outside the mission case and can be switched to the regulation release state. The brake operation shaft can be pulled out of the transmission case with a simple operation without requiring complicated operations such as disassembling the transmission case.
Therefore, there is an advantage that it is easy to perform maintenance work and the like by pulling the brake operation shaft out of the transmission case without requiring complicated work such as disassembling the transmission case.

[Solution 2]
Another technical means of the present invention taken in order to solve the above problem is that the brake operating shaft is formed with an engaging portion with the restricting member outside the transmission case.

[Operation and effect of invention according to Solution 2]
According to the configuration of the invention relating to the above solution 2, the brake operating shaft is configured so that the engaging portion with the regulating member is located outside the transmission case, so that the braking is performed with the regulating member located outside the transmission case. There is an advantage that the movement of the operation shaft to the exit side can be regulated.

[Solution 3]
Another technical means of the present invention taken in order to solve the above-mentioned problem is that a portion of the brake operation shaft inserted inside the transmission case is rotated around the axis of the brake operation shaft. Is provided with a pressing operation part for switching the brake equipped in the transmission case between a braking state and a braking release state, and the pressing operation part is viewed in the axial direction of the brake operation shaft. This means that the brake operation shaft is formed within the range of the shaft cross-sectional area at a location penetrating the case wall of the transmission case.

[Operation and effect of invention according to Solution 3]
According to the configuration of the invention relating to the above solution 3,
The range of the shaft cross-sectional area at the point where the pressing operation part for switching the brake between the braking state and the braking release state is viewed from the axial direction of the brake operation shaft and the brake operation shaft penetrates the case wall of the transmission case Therefore, the brake operation shaft can be easily pulled out easily.

[Solution 4]
Another technical means of the present invention taken to solve the above problem is that the regulating member is configured to be detachable from the transmission case.

[Operations and effects of invention according to Solution 4]
According to the configuration of the invention relating to the solution means 4 described above, since the regulating member is configured to be detachable from the transmission case, the shape of the transmission case becomes complicated as in the case of being formed integrally with the transmission case. This is advantageous in that there is no fear.

[Solution 5]
Another technical means of the present invention taken in order to solve the above problem is that the restricting member is configured to be detachable by moving in a radial direction with respect to the brake operation shaft.

[Operation and effect of invention according to Solution 5]
According to the configuration of the invention relating to the above solution 5,
Since the regulating member can be attached to and detached from the brake operating shaft by moving the regulating member in the radial direction relative to the brake operating shaft, for example, the regulating member is moved in the axial direction of the brake operating shaft, and the axial direction This is advantageous in that the attaching / detaching operation can be easily performed as compared with the structure in which the attaching / detaching operation can be performed by detaching it from the end portion.

[Solution 6]
Another technical means of the present invention taken to solve the above problem is that the restricting member is configured to be connected and fixed to a case wall of the transmission case with a fixing bolt.

[Operations and Effects of Invention According to Solution 6]
According to the configuration of the invention relating to the solution means 6 described above, there is an advantage that a structure with a simple structure using a fixing bolt and a connection release structure can be obtained.

[Solution 7]
Another technical means of the present invention taken to solve the above-mentioned problems is that the fixing bolt is a single one, the distance of the restricting member in the radial direction with respect to the brake operation shaft, and the transmission case That is, it is configured to regulate the separation of the regulating member from the case wall.

[Operation and effect of invention according to Solution 7]
According to the configuration of the invention relating to the above solution 7, there is an advantage that the regulating member can be fixed with a simple structure using only a single fixing bolt.

[Solution 8]
Another technical means of the present invention taken to solve the above-described problem is that the regulating member swings within a predetermined range around the axis of the fixing bolt in a state where the fastening fixing by the fixing bolt is not completed. A stopper configured to set a swingable range of the restricting member, and the swingable range by the stopper is determined by the restricting member swung around the axis of the fixing bolt. That is, it is set in a range that can prevent contact with the outer peripheral surface of the brake operation shaft.

[Operation and effect of invention according to Solution 8]
According to the configuration of the invention relating to the solving means 8 described above, there is an advantage that the stopper can suppress contact with the outer peripheral surface of the brake operation shaft when the regulating member is attached and detached, and damage to the outer peripheral surface of the brake operation shaft can be avoided.

[Solution 9]
Another technical means of the present invention taken in order to solve the above problem is that the stopper is provided on both ends of the swingable range of the restricting member.

[Operations and effects of invention according to Solution 9]
According to the configuration of the invention relating to the solving means 9 described above, the stoppers are provided at both ends of the swingable range of the restricting member. Therefore, in any case, when the restricting member is fixed by the fixing bolt and when the fixing is released. In addition, there is an advantage that the contact of the regulating member to the outer peripheral surface of the brake operation shaft can be suppressed.

[Solution 10]
Another technical means of the present invention taken to solve the above problem is that the stopper is constituted by a part of the mission case.

[Operations and Effects of Invention According to Solution 10]
According to the configuration of the invention relating to the above solution 10, since a part of the mission case serves as a stopper, there is no need to separately attach a stopper, and there is an advantage that the number of parts can be reduced.

[Solution 11]
Another technical means of the present invention taken in order to solve the above-described problem is that the projecting end portion of the brake operation shaft toward the outer side of the transmission case is located outside the main frame provided in the vehicle body frame. And an arm portion for linking with the brake pedal is mounted on the extended end portion in a state of being located outside the main frame.

[Operations and Effects of Invention According to Solution 11]
According to the configuration of the invention relating to the solving means 11, the projecting end portion of the brake operating shaft to the outer side of the transmission case extends to the outside of the main frame, and the arm portion for linking with the brake pedal is provided. Since it is provided at the extended end, there is an advantage that the brake operation shaft can be attached to and detached from the transmission case without requiring disassembly work of the main frame.

[Solution 12]
Another technical means of the present invention taken to solve the above-mentioned problem is that the brake pedal is provided so as to be swingable around a lateral pivot shaft that intersects the longitudinal direction of the main frame. The tread surface portion is an arm portion that is directed to the opposite side across the pivot axis, and extends linearly in a direction intersecting the pivot axis, and the arm portion and the brake operation shaft That is, the linkage arm portion is connected.

[Operations and Effects of Invention According to Solution 12]
According to the configuration of the invention relating to the solving means 12, the arm extended to the side opposite to the side where the tread surface portion exists across the pivot axis is connected to the linkage arm portion of the brake operation shaft. Therefore, there is an advantage that the linkage arm portion of the brake operation shaft can be easily operated lightly by lever action with the pivot shaft as a fulcrum.

[Solution 13]
The other technical means of the present invention taken to solve the above-mentioned problems include a brake installed in a transmission case, a brake operation shaft for operating the brake from outside the transmission case, and the brake. A brake pedal for operating the operating shaft, and a regulating member for restricting the brake operating shaft from coming out of the mission case is provided outside the mission case, and the regulating member is pulled out and the regulation is released. The brake operation shaft is formed with an engaging portion with the restriction member on the outside of the transmission case, and is inserted into the inside of the transmission case of the brake operation shaft. Is installed in the transmission case by a turning operation around the axis of the brake operation shaft. A pressing operation part for switching the brake being switched between a braking state and a braking release state, and the pressing operation part is viewed from the axial direction of the brake operation shaft, and the brake operation shaft is connected to the transmission case. It is formed in the range of the axial cross-sectional area in the location which penetrates a case wall, and it is that the said control member is comprised so that attachment or detachment is possible with respect to the said mission case.

[Operations and Effects of Invention According to Solution 13]
According to the configuration of the invention relating to the solving means 13 described above, the same actions and effects as the solving means 1, 2, 3, 4 are achieved.

[Solution 14]
The other technical means of the present invention taken to solve the above-mentioned problems include a brake installed in a transmission case, a brake operation shaft for operating the brake from outside the transmission case, and the brake. A brake pedal for operating the operating shaft, and a regulating member for restricting the brake operating shaft from coming out of the mission case is provided outside the mission case, and the regulating member is pulled out and the regulation is released. The brake operation shaft is formed with an engaging portion with the restriction member on the outside of the transmission case, and is inserted into the inside of the transmission case of the brake operation shaft. Is installed in the transmission case by a turning operation around the axis of the brake operation shaft. A pressing operation part for switching the brake being switched between a braking state and a braking release state, and the pressing operation part is viewed from the axial direction of the brake operation shaft, and the brake operation shaft is connected to the transmission case. The restriction member is formed within a range of an axial cross-sectional area at a portion penetrating the case wall, and the restriction member is detachable by moving in a radial direction with respect to the brake operation shaft and is single with respect to the case wall of the transmission case The fixing member is configured to be swingable within a predetermined range around the axis of the fixing bolt in a state in which the fixing fixing by the fixing bolt is not completed. And a stopper for setting a swingable range of the regulating member. The swingable range by the stopper swings around the axis of the fixing bolt. In addition, the restriction member is set in a range in which it can be prevented from coming into contact with the outer peripheral surface of the brake operation shaft, and the stoppers are provided at both ends of the swingable range of the restriction member. It is composed of parts.

[Operations and Effects of Invention According to Solution 14]
According to the configuration of the invention relating to the solving means 14, the same actions and effects as the solving means 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 are obtained.

[Solution 15]
The other technical means of the present invention taken to solve the above-mentioned problems include a brake installed in a transmission case, a brake operation shaft for operating the brake from outside the transmission case, and the brake. A brake pedal for operating the operating shaft, and a regulating member for restricting the brake operating shaft from coming out of the mission case is provided outside the mission case, and the regulating member is pulled out and the regulation is released. The brake operation shaft is formed with an engaging portion with the restriction member on the outside of the transmission case, and is inserted into the inside of the transmission case of the brake operation shaft. Is installed in the transmission case by a turning operation around the axis of the brake operation shaft. A pressing operation part for switching the brake being switched between a braking state and a braking release state, and the pressing operation part is viewed from the axial direction of the brake operation shaft, and the brake operation shaft is connected to the transmission case. The restriction member is formed within a range of an axial cross-sectional area at a portion penetrating the case wall, and the restriction member is detachable by moving in a radial direction with respect to the brake operation shaft and is single with respect to the case wall of the transmission case The fixing member is configured to be swingable within a predetermined range around the axis of the fixing bolt in a state in which the fixing fixing by the fixing bolt is not completed. And a stopper for setting a swingable range of the regulating member. The swingable range by the stopper swings around the axis of the fixing bolt. In addition, the restriction member is set in a range in which it can be prevented from coming into contact with the outer peripheral surface of the brake operation shaft, and the stoppers are provided at both ends of the swingable range of the restriction member. The projecting end portion of the brake operation shaft to the outer side of the transmission case is extended to the outside of the main frame that is long in the front-rear direction provided in the vehicle body frame, and the extension end portion An arm portion for linking with a brake pedal is equipped in a state of being located outside the main frame, and the brake pedal is equipped so as to be swingable around a lateral pivot shaft that intersects the longitudinal direction of the main frame. An arm portion directed to the opposite side across the pivot axis extends from the tread surface portion of the brake pedal, and extends in a direction perpendicular to the pivot axis. This means that the linkage arm portion of the brake operation shaft is connected.

[Operations and Effects of Invention According to Solution 15]
According to the configuration of the invention relating to the solving means 15, the same actions and effects as the solving means 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12 are obtained.

It is a right view of a riding type rice transplanter. It is a right view which shows a mission case and a vehicle body frame. It is a top view which shows a mission case. It is a longitudinal cross-sectional view of a mission case. It is sectional drawing which shows the lower bearing location of a steering shaft. It is a perspective view of a mission case main part. It is a diagram which shows the power transmission system to a traveling apparatus. It is a diagram which shows the power transmission system | strain to a seedling planting apparatus. It is sectional drawing which shows the brake operation shaft of a traveling apparatus. It is a rear view which shows the arrangement | positioning state of a brake pedal and a brake operation axis | shaft. The brake operation shaft and the regulating member are shown, (A) is an exploded perspective view, and (B) is a perspective view in an assembled state. It is sectional drawing which shows the operating state of a control member. It is a perspective view which shows the attachment state of a brake pedal. It is explanatory drawing which shows the linkage structure of a main transmission lever and a back clutch operation shaft.

Hereinafter, an example of an embodiment of the present invention will be described based on the drawings.
〔overall structure〕
FIG. 1 shows a right side surface of a riding type rice transplanter as an example of a work vehicle.
This riding type rice transplanter includes a pair of left and right steering operations and driveable front wheels 11F and a pair of left and right driveable rear wheels 11R below the body frame 10, and an engine E mounted on the body frame 10. The self-propelled traveling vehicle body 1 in which the front wheels 11F and the rear wheels 11R are driven by the power from the vehicle is provided.
The traveling vehicle body 1 is provided with a prime mover 13 with an engine E built in at the front of the fuselage, and reserve seedling platforms 14 are provided on the left and right sides thereof. A boarding driving unit having a steering handle 15 and a driving seat 12 for steering the front wheel 11F is provided at the center in the front-rear direction of the traveling vehicle body 1 on the rear side of the driving unit 13. A seedling planting device 2 is supported at a rear portion of the traveling vehicle body 1 through a link mechanism 17 having a lift cylinder 18 so as to be movable up and down.
The riding type rice transplanter configured in this way performs planting work of seedlings such as rice on the field as “ground work” by the seedling planting device 2.

  The seedling planting device 2 is configured in an eight-row planting type, and includes four transmission cases 21, a planting case 22 supported rotatably on the right and left lateral sides of the rear portion of the transmission case 21, A pair of planting arms 23 provided at both ends of the attached case 22, a grounding float 24, a seedling platform 20 on which a seedling is placed, and the like are provided. As a result, the planting case 22 is rotationally driven as the seedling platform 20 is reciprocated laterally to the left and right, and the planting arm 23 alternately takes out seedlings from the lower part of the seedling platform 20 and puts them on the rice field. Configured to plant.

  A transmission case 3 that pivotally supports a front wheel 11F is connected and fixed to the front portion of the vehicle body frame 10 in the traveling vehicle body 1, and a rear transmission case 19 equipped with rear wheels 11R on the left and right is provided at the rear portion of the vehicle body frame 10. It is supported so that it can roll. A front frame 10F extends forward from the mission case 3, and an engine E is mounted sideways on the front frame 10F.

  As shown in FIGS. 2 to 4, on the left and right sides of the transmission case 3, the front axle case 3A extends left and right, and left and right front wheels 11F and 11F are provided. A torque generator 4 (corresponding to a power steering device) is provided on the upper side of the transmission case 3, and a steering handle 15 is provided at the upper end of a steering operation shaft 15 a erected upward from the torque generator 4. . A main speed change lever 16 (corresponding to a speed change operation lever) for changing the vehicle speed by operating a hydrostatic continuously variable transmission 61 (described later) is disposed on the side portion of the steering handle 15.

[Power transmission system]
A power transmission system in which the power of the engine E is transmitted to the front wheels 11F and the rear wheels 11R of the travel drive system, and a power transmission system that is transmitted to the seedling planting device 2 as a work device will be described.

[About driving system]
As shown in FIG. 3, a pair of left and right front axle cases 3 </ b> A are provided on the left and right sides of the mission case 3. The front wheel case 3A supports the front wheel 11F so that it can be steered by turning around an axis along the vertical direction.

  As shown in FIGS. 3 and 7, a hydrostatic continuously variable transmission 61 is connected to the mission case 3 in a state of being located on the left lateral portion on the upper side of the mission case 3. The hydrostatic continuously variable transmission 61 has a neutral stop position, and is configured to be steplessly variable from the neutral stop position to the forward side and the reverse side. The hydrostatic continuously variable transmission 61 has a transmission input shaft 61a and a transmission output shaft 61b that extend to the outside. The power of the engine E is transmitted to the transmission input shaft 61a of the hydrostatic continuously variable transmission 61 through the belt transmission mechanism 61c. A portion of the speed change input shaft 61 a located on the opposite side of the belt transmission mechanism 61 c and the speed change output shaft 61 b are arranged so as to enter the inside of the transmission case 3.

  A hydraulic pump 62 is connected to the right side portion of the mission case 3. The pump input shaft 62 a of the hydraulic pump 62 is disposed so as to enter the inside of the mission case 3. The pump input shaft 62a is arranged concentrically with the speed change input shaft 61a, and is splined so as to rotate integrally with the speed change input shaft 61a by an extension input shaft 61d. As a result, the power of the engine E is transmitted from the transmission input shaft 61a of the hydrostatic continuously variable transmission 61 to the hydraulic pump 62, and the hydraulic pump 62 is driven.

  A first transmission shaft 63 that is rotatably supported inside the transmission case 3 is splined to the transmission output shaft 61b. The first transmission shaft 63 is provided with a first shift gear 64 that rotates integrally with the first transmission shaft 63 and is slidable with respect to the first transmission shaft 63 by a spline structure. . The first shift gear 64 is integrally provided with a first high speed gear 64a and a first low speed gear 64b having a diameter larger than that of the first high speed gear 64a.

  On the lower transmission side of the first transmission shaft 63, a second transmission shaft 65 parallel to the first transmission shaft 63 is supported and provided in the transmission case 3. The second transmission shaft 65 is provided with a large-diameter gear 65 a and a medium-diameter gear 65 b smaller in diameter than the large-diameter gear 65 a fixed to the second transmission shaft 65. By shifting the first shift gear 64, one of the meshing of the first high speed gear 64a and the large diameter gear 65a and the meshing of the first low speed gear 64b and the medium diameter gear 65b is selected. Power can be transmitted from the transmission shaft 63 to the second transmission shaft 65. A small-diameter gear 65c having a smaller diameter than the medium-diameter gear 65b is fixed to the second transmission shaft 65.

  On the lower transmission side of the second transmission shaft 65, a third transmission shaft 67 parallel to the second transmission shaft 65 is supported and provided in the transmission case 3. The third transmission shaft 67 is provided with a second shift gear 68 that rotates integrally with the third transmission shaft 67 and is slidable with respect to the third transmission shaft 67 by a spline structure. . The second shift gear 68 is integrally provided with a second high speed gear 68a and a second low speed gear 68b having a diameter larger than that of the second high speed gear 68a. By shifting the second shift gear 68, either the meshing of the medium diameter gear 65b and the second high speed gear 68a or the meshing of the small diameter gear 65c and the second low speed gear 68b is selected, and the second transmission Power can be transmitted from the shaft 65 to the third transmission shaft 67. A transmission gear 69 is fixed to the third transmission shaft 67. A first bevel gear 70 is fixed to the third transmission shaft 67.

  On the lower transmission side of the third transmission shaft 67, a pair of front transmission shafts 71 are arranged in contact with each other in parallel with the third transmission shaft 67. A differential mechanism 72 is provided between the pair of front transmission shafts 71. A differential case 72 a of the differential mechanism 72 is rotatably supported inside the mission case 3. A transmission gear 69 fixed to the third transmission shaft 67 is meshed with a driven gear 72b fixed to the differential case 72a.

  A differential lock body 72c is externally fitted to one front transmission shaft 71 of the pair of front transmission shafts 71 so as to be integrally rotatable and slidable by a key structure. The differential lock body 72c can be switched between a differential enabled state (diff lock released state) released from the differential case 72a and a differential disabled state (diff locked state) engaged with the differential case 72a. It is configured.

  As shown in FIGS. 2 and 7, the rear portion of the mission case 3 is provided with a travel output shaft 74 that protrudes rearward from the rear end portion of the mission case 3. A second bevel gear 75 is provided at the front end of the travel output shaft 74. The second bevel gear 75 is meshed with the first bevel gear 70 fixed to the third transmission shaft 67, whereby power is transmitted from the third transmission shaft 67 to the travel output shaft 74.

  A rear transmission case 19 that supports the pair of left and right rear wheels 11R is provided, and a rear transmission shaft 77 is interlocked and linked between the travel output shaft 74 and the rear transmission shaft 76 of the rear transmission case 19. . The power transmitted to the rear transmission shaft 76 is transmitted to the left and right rear wheels 11R via the side clutch 73, respectively.

  As a result, the power of the engine E causes the transmission output shaft 61b, the first transmission shaft 63, the second transmission shaft 65, the third transmission shaft 67, the differential mechanism 72, and the front transmission shaft 71 of the hydrostatic continuously variable transmission 61 to be transmitted. Via the differential case 72a of the differential mechanism 72, the travel output shaft 74, and the rear transmission shaft 76, and then transmitted to the pair of left and right rear wheels 11R.

[About work equipment drive system]
Next, the transmission structure to the seedling planting device 2 which is a working device will be described.
As shown in FIG. 8, on the lower transmission side of the second transmission shaft 65, a fourth transmission shaft 80 parallel to the second transmission shaft 65 is supported and provided in the transmission case 3. A work output gear 81 is provided on the second transmission shaft 65 so that power is transmitted via a back clutch 100 described later. The power of the second transmission shaft 65 is configured to be transmitted from the work output gear 81 to the fourth transmission shaft 80 via the torque limiter T.

  The fourth transmission shaft 80 is provided with a planting shift gear 84 that rotates integrally with the fourth transmission shaft 80 and is slidable with respect to the fourth transmission shaft 80 by a spline structure. Yes. The planting shift gear 84 is integrally provided with a first planting low speed gear 84a and a first planting high speed gear 84b having a smaller diameter than the first planting low speed gear 84a.

  The first transmission shaft 63 includes a first loose-fitting gear 85a, a second loose-fitting gear 85b, a third loose-fitting gear 85c, a fourth loose-fitting gear 85d, and a fifth loose-fitting gear 85e. On the other hand, it is supported so as to be relatively rotatable. The first loose-fitting gear 85a, the second loose-fitting gear 85b, the third loose-fitting gear 85c, the fourth loose-fitting gear 85d, and the fifth loose-fitting gear 85e are fixed to each other so as to rotate together. The diameters of the gears are set such that the first loose-fit gear 85a, the second loose-fit gear 85b, the third loose-fit gear 85c, the fourth loose-fit gear 85d, and the fifth loose-fit gear 85e increase in order. .

  The planting shift gear 84 is engaged with the first planting low-speed gear 84a and the first loose-fitting gear 85a and the first planting high-speed gear 84b by sliding the second speed change operation rod 27. And meshing with the fifth loose-fitting gear 85e can be selected. Thus, the power transmitted from the planting shift gear 84 to the lower transmission side can be shifted in two stages. As described above, the planting shift gear 84, the second speed change operating rod 27, the first loosely fitted gear 85a, the fifth loosely fitted gear 85e, and the like constitute the second speed change mechanism S2 disposed in the transmission case 3. Yes. That is, the second speed change mechanism S2 shifts the power from the engine E to two stages (an example of “multiple stages”), so that the seedling as “ground work” by the seedling planting device 2 that is the “work apparatus”. Change the planting interval (between stocks) in two stages.

  A fifth transmission shaft 86 parallel to the first transmission shaft 63 is supported in the transmission case 3 on the lower transmission side of the fourth transmission shaft 80 and the first transmission shaft 63. The fifth transmission shaft 86 is provided with a first transmission gear 87a, a second transmission gear 87b, a third transmission gear 87c, and a fourth transmission gear 87d that are supported in a relatively rotatable manner. The diameters of the gears are such that the first transmission gear 87a, the second transmission gear 87b, the third transmission gear 87c, and the fourth transmission gear 87d become smaller in this order. The first transmission gear 87a is always meshed with the first loose gear 85a, the second transmission gear 87b is always meshed with the second loose gear 85b, and the third transmission gear 87c is meshed with the third loose gear 85c. The fourth transmission gear 87d is always meshed with the fourth loosely engaging gear 85d. A third bevel gear 88 is fixed to the fifth transmission shaft 86.

  The fifth transmission shaft 86 is provided by the large-diameter cam portion 26a provided on one end side of the first transmission operation rod 26 by sliding the first transmission operation rod 26 inserted in the center of the fifth transmission shaft 86 in the axial direction. A transmission ball (not shown) engaged with and supported by is pushed outward and displaced in the radial direction. By engaging the transmission ball with the central hole of any one of the first transmission gear 87a, the second transmission gear 87b, the third transmission gear 87c, and the fourth transmission gear 87d, Only one set is selected for meshing transmission, and the power transmitted to the driven fifth transmission shaft 86 can be shifted in four stages. As described above, the first transmission gear 87a, the second transmission gear 87b, the third transmission gear 87c, the fourth transmission gear 87d, the first speed change operation rod 26, the transmission ball, and the like are arranged in the mission case 3. A transmission mechanism S1 is configured. In other words, the first speed change mechanism S1 shifts the power from the engine E to four stages (an example of “multiple stages”), so that the seedling as “ground work” by the seedling planting device 2 that is the “work apparatus”. Change the planting interval (between stocks) to 4 levels.

  As described above, the power of the planting system is changed to a total of eight speeds by combining the four speeds by the operation of the first speed change operation rod 26 and the two speeds by the operation of the second speed change rod 27. It is configured to be able to do.

  On the rear side of the mission case 3, a cylindrical body 90 that is supported so as to be rotatable relative to the mission case 3 is provided. The cylindrical body 90 is provided with a fourth bevel gear 91. The fourth bevel gear 91 is meshed with a third bevel gear 88 fixed to the fifth transmission shaft 86.

  At the rear part of the mission case 3, a planting output shaft 92 that protrudes rearward from the rear end part of the mission case 3 and that is concentrically with the cylindrical body 90 and is located inside the cylindrical body 90 is provided. A planting clutch 93 that rotates integrally with the planting output shaft 92 and is slidable with respect to the planting output shaft 92 is externally fitted to the planting output shaft 92 by a spline structure. . The planting clutch 93 can be switched between an engagement state in which the planting clutch 93 is engaged and a disengagement state in which the planting clutch 93 is not engaged with the cylinder 90. When the planting clutch 93 is engaged, the power of the fifth transmission shaft 86 is transmitted to the planting output shaft 92 via the third bevel gear 88, the fourth bevel gear 91, the cylindrical body 90, and the planting clutch 93. Communicated. On the other hand, when the planting clutch 93 is disengaged, power transmission from the fifth transmission shaft 86 to the planting output shaft 92 can be cut off. The planting clutch 93 is urged toward the engaged state, and by switching the operation shaft 94 supported by the bush 95, the planted clutch 93 is switched between the engaged state and the disengaged state. It is configured.

  As shown in FIG. 8, the power of the planting output shaft 92 is transmitted to the input shaft 98 of the feed case 97 via the rotation transmission shaft 96. By the power input to the input shaft 98, the seedling raising table 20 is reciprocated in conjunction with the driving of the planting arm 23 and the seedling planting operation of the planting arm 23. Thus, seedlings are planted on the farm surface at a planting speed that is shifted by the first transmission mechanism S1 and the second transmission mechanism S2 in accordance with the traveling speed of the machine body. Thereby, rice planting can be performed at a desired planting interval (between plants) by operating the first transmission mechanism S1 and the second transmission mechanism S2.

[Mission case structure]
The internal structure of the mission case 3 is shown in FIGS.
The mission case 3 is a divided case body composed of a box-shaped case main body 30 having an opening 30a on one end side in the left-right direction and a lid-like case 31 provided so as to close the opening 30a. It is comprised by the combination of. The case main body 30 and the lid-like case 31 are made of aluminum die cast, and are integrated by bolting the lid-like case 31 so as to face the opening 30a of the case main body 30.
As shown in FIGS. 4 and 6, the case body 30 includes a front wall 30 f that forms the front surface of the box-shaped mission case 3 in the aircraft traveling direction, a rear wall 30 r that forms the rear surface of the mission case 3, An upper wall 30t constituting the upper surface of the mission case 3, a bottom wall 30b constituting the bottom surface of the mission case 3, and a lateral wall 30s constituting the left side surface of the mission case 3 are provided. The lid-like case portion 31 constitutes the right side surface of the mission case 3, and the mission case 3 is formed in a substantially rectangular box shape as a whole.

As shown in FIGS. 2 to 4, the hydraulic torque generator 4 as a power steering device is mounted on the upper surface of the transmission case 3 in a slightly tilted posture at the front position of the upper wall 30 t of the case body 30. Has been. From the torque generator 4, the steering operation shaft 15 a extends obliquely rearward and upward. From the lower side of the torque generator 4, an output shaft 4 a that is coaxial with the steering operation shaft 15 a and faces downward is arranged so as to enter the mission case 3.
A steering shaft 41 is connected to the lower end side of the output shaft 4a coaxially with the output shaft 4a and the steering operation shaft 15a via a joint 40 having a spline portion on the inner peripheral side. That is, a spline is formed on the outer periphery of the upper end portion 41 a of the steering shaft 41 and is engaged with the spline on the inner peripheral side of the joint 40.

As shown in FIGS. 4 to 6, a bottom opening 32 for inserting / removing the steering shaft 41 is formed at a front position on the bottom wall 30 b side of the case main body 30 of the transmission case 3.
The bottom opening 32 is formed so that the steering shaft 41 can be inserted / removed from the lower side of the transmission case 3, and a lower bearing 43 d (lower first 1) for pivotally supporting the lower end side of the steering shaft 41. It is also used as a mounting portion corresponding to a bearing portion.
In the steering shaft 41, a pinion gear 42 is integrally formed near the lower end opposite to the upper end portion 41a, and the lower bearing 43d is a shaft portion that extends downward from a position where the pinion gear 42 of the steering shaft 41 exists. And is fitted into the bottom opening 32.

The bottom wall 30b of the case main body 30 of the mission case 3 rotates integrally with the pitman arm 44 at a position farther rearward than the position where the bottom opening 32 for inserting and removing the steering shaft 41 is formed. Another bottom opening 33 for mounting the arm support shaft 45 provided in this manner is formed. The other bottom opening 33 is also used as a mounting portion for a lower bearing 48d (corresponding to a lower second bearing portion) for pivotally supporting the arm support shaft 45.
A spline that engages with a spline formed on the inner peripheral side of the sect gear 46 (corresponding to the steering gear) is provided on the outer peripheral surface above the portion pivotally supported by the lower bearing 48d of the arm support shaft 45. The sect gear 46 is formed so that it can be inserted into and removed from the arm support shaft 45 and is integrally rotated.

The sect gear 46 meshes with the pinion gear 42 of the steering shaft 41, and the sect gear 46 is rotated as the steering shaft 41 rotates. As the sect gear 46 rotates, the pitman arm 44 swings within a predetermined angle range via the arm support shaft 45.
The tie rod 47 connected to the free end portion of the pitman arm 44 is interlocked and connected to a knuckle arm (not shown) so that the left and right front wheels 11F and 11F are steered according to the swing operation amount of the pitman arm 44. It is configured.

As shown in FIGS. 4 and 5, the steering shaft 41 has an upper bearing 43 u (upper first shaft 43) not only on the shaft portion extending downward from the position where the pinion gear 42 exists but also on the upper side of the pinion gear 42. It corresponds to one bearing part).
As shown in FIGS. 4 to 6, the upper bearing 43 u is attached to the shaft side attachment portion 34 that extends horizontally from the front wall 30 f and the lateral wall 30 s of the mission case 3 in the mission case 3. Yes.
As shown in FIG. 5, the shaft side mounting portion 34 has a recess 34a in which the upper bearing 43u can be fitted from below on the lower surface side, and the steering shaft 41 is pivoted by fitting the upper bearing 43u from below. It is configured to support.

The outer diameters of the upper bearing 43u and the lower bearing 43d are slightly smaller than the inner diameter D3 of the bottom opening 32, can be fitted with appropriate fitting tolerances, and can be inserted / removed through the bottom opening 32 of the mission case 3. It is configured. Further, the inner diameters of the upper bearing 43u and the lower bearing 43d are slightly larger than the outer diameter D1 of the steering shaft 41, are fitted with appropriate fitting tolerances, and are larger than the outer diameter D2 of the pinion gear 42. It is set small.
The upper bearing 43u and the lower bearing 43d are in contact with the upper and lower edges of the pinion gear 42 so that the pinion gear 42 is sandwiched vertically, and the upper bearing 43u is fitted into the recess 34a, and the lower bearing 43d is opened at the bottom. In 32, the retaining ring 32a holds the retaining state.

As shown in FIGS. 4 and 5, the arm support shaft 45 is not limited to the shaft portion positioned below the position where the sect gear 46 exists, but also on the upper side of the sect gear 46, the upper bearing 48 u (upper second bearing). Is equivalent to the department).
As shown in FIGS. 4 to 6, the upper bearing 48 u is attached to the arm-side attachment portion 36 that extends from the lateral wall 30 s of the mission case 3 in the horizontal direction inside the mission case 3.
As shown in FIG. 5, the arm side mounting portion 36 is formed with a recess 36a into which the upper bearing 48u can be inserted from below on the lower surface side, and the arm bearing shaft 45 can be fitted by inserting the upper bearing 48u from below. It is configured to pivot.

The outer diameters of the upper bearing 48u and the lower bearing 48d are slightly smaller than the inner diameter D6 of the bottom opening 33, can be fitted with an appropriate fit tolerance, and can be inserted / removed through the bottom opening 33 of the mission case 3. It is configured.
Further, the inner diameter of the lower bearing 48d is slightly larger than the outer diameter D5 of the spline portion of the arm support shaft 45 and is fitted with an appropriate fit tolerance. The shaft 45 is slightly larger in diameter than the outer diameter D4 in the shaft portion above the spline portion of the support shaft 45, and is fitted with an appropriate fit tolerance.
The upper bearing 48u and the lower bearing 48d are in contact with the upper and lower edges of the sect gear 46, and the upper bearing 48u is fitted into the recess 36a with the sect gear 46 sandwiched vertically, and the lower bearing 48d is opened at the bottom. In 33, the retaining ring 33a holds the retaining state.

As shown in FIGS. 4 to 6, the shaft-side attachment portion 34 and the arm-side attachment portion 36 are integrated with each other by an intermediate connection portion 35 that is located between the shaft-side attachment portion 34 and the arm-side attachment portion 36. It is connected. Since the intermediate connecting portion 35 is formed in a rib shape from the inner surface of the left lateral wall 30s of the case main body portion 30 and is not formed with a concave portion for attaching a bearing or the like, the thickness in the vertical direction is as shown in the figure. It is thinner than the shaft-side mounting portion 34 and the arm-side mounting portion 36, and is formed so as to protrude less from the left lateral wall 30 s than the shaft-side mounting portion 34 and the arm-side mounting portion 36 in plan view.
That is, the shaft-side mounting portion 34 to which the upper bearing 43u that supports the steering shaft 41 is mounted and the arm-side mounting portion 36 to which the upper bearing 48u that supports the arm support shaft 45 is mounted are positioned in the vertical direction with respect to the intermediate connection portion 35. And is formed wider in the horizontal direction than in the intermediate connection portion 35 even in the horizontal direction.
The intermediate connection portion 35 has a smaller thickness and a smaller area than the shaft side attachment portion 34 and the arm side attachment portion 36, but the mission can be achieved by connecting the shaft side attachment portion 34 and the arm side attachment portion 36. While avoiding an increase in the weight of the case 3 as much as possible, the strength of the shaft side mounting portion 34 and the arm side mounting portion 36 can be effectively increased.

A vertical rib 37 is integrally formed on the arm side mounting portion 36 over the upper surface of the arm side mounting portion 36 and the left horizontal wall 30 s of the case main body portion 30 of the transmission case 3. The vertical rib 37 has a vertical plate surface parallel to the axis of the arm spindle 45 supported by the arm side mounting portion 36, and reinforces the vertical load acting on the arm side mounting portion 36. It is provided so that it can be performed effectively.
The vertical ribs 37 are provided on the front and rear sides of the upper bearing 48 u that pivotally supports the arm support shaft 45. Of the front and rear vertical ribs 37, the vertical ribs 37 b farther from the steering shaft 41 are formed larger than the vertical ribs 37 a closer to the steering shaft 41.
Moreover, both the vertical ribs 37a and 37b are connected to each other by a horizontal rib 38 along the horizontal direction, and are configured to further increase the rigidity.

[Brake operation system structure]
As shown in FIGS. 7 and 9 to 13, a brake 78 capable of braking the traveling vehicle body 1 by applying a rotational resistance to the traveling output shaft 74 is provided in the rear portion of the transmission case 3. A brake operation mechanism 5 that applies a braking force to the brake 78 by manual operation is provided on the right side of the transmission case 3 and the vehicle body frame 10 on which the transmission case 3 is disposed.

The brake operation mechanism 5 is configured to link and operate the brake pedal 50, the pivot shaft 51 that pivotally supports the brake pedal 50, the brake operation shaft 52, and the pivot shaft 51 and the brake operation shaft 52. The linkage mechanism 53 is provided.
As shown in FIGS. 3, 10, and 13, the brake pedal 50 includes a tread surface portion 50 a that can be stepped on with a foot. At the connecting portion between the tread surface portion 50a and the pivot shaft 51, the front support rod 50b extending from the pivot shaft 51 to the tread surface portion 50a, and the rear support rod 50b extending from the pivot shaft 51 to the opposite side. A support rod 50c, a cylindrical portion 50d fitted on the pivot shaft 51, and an operation arm 50e integrally formed at the end of the cylindrical portion 50d on the inward side of the machine body and extending rearward are provided. ing.
Then, the front support rod 50b and the rear support rod 50c are fixed to the cylindrical portion 50d, and the brake pedal 50 is swung by connecting the end portion of the rear support rod 50c and the extending end side of the operation arm 50e. The mounting strength of the brake pedal 50 is improved by forming a frame-shaped mounting portion in the peripheral portion of the pivot shaft 51 having the pivot axis x1 that pivots freely.

A flat plate-like connection plate 50f is interposed at a place where the front support rod 50b and the rear support rod 50c are fixed to the cylindrical portion 50d.
That is, the front support rod 50b and the rear support rod 50c, which are a part of the brake pedal 50, are configured by pipe-shaped members having a circular arc-shaped cross section, and a cylindrical portion 50d that is externally fitted to the pivot shaft 51. Also, the cross section is constituted by a pipe-shaped member having an arcuate peripheral surface.
The axial direction of the front support rod 50b and the rear support rod 50c intersects with the axial direction of the cylindrical portion 50d fitted on the pivot shaft 51 in a direction substantially perpendicular to each other. For this reason, in the location where the arcuate peripheral surface of the front support rod 50b and the rear support rod 50c intersects the arcuate peripheral surface of the cylindrical portion 50d, the contact state is almost in a point contact state.
In such a contact location, since the welding allowance when welding and joining is extremely reduced, in the present invention, the front support rod is provided by interposing the connection plate 50f between the contact locations. 50b, the rear support rod 50c, and the connection plate 50f are in a substantially line contact state, and the cylindrical portion 50d and the connection plate 50f are also in a substantially line contact state. As a result, a sufficient weld length along the longitudinal direction of the front support rod 50b and the rear support rod 50c and the longitudinal direction of the cylindrical portion 50d can be secured, and the required connection strength can be easily secured.

As shown in FIGS. 2 and 10, the pivot shaft 51 that pivots the brake pedal 50 passes through a fixed bracket 10 </ b> B extending downward from a pair of left and right main frames 10 </ b> A constituting the vehicle body frame 10. The bracket is rotatably mounted on the fixed bracket 10B. The cylindrical portion 50d is fitted on the right outer end of the pivot shaft 51, and is connected and supported so as to rotate integrally with a connection pin (not shown).
As shown in FIG. 2 and FIG. 10, an arm rod 51 a that rotates integrally with the pivot shaft 51 is erected upward on the pivot shaft 51 at an intermediate position in the left-right direction. A return spring 56 is stretched between the free end portion of the armband 51a and the locking piece 10C fixed to the main frame 10A so as to perform a return bias after the brake pedal 50 is depressed. Has been.

As shown in FIGS. 9 to 11, the brake operation shaft 52 is supported in an inserted state in a support hole 39 provided at the rear part of the transmission case 3 on one end side, and is connected to the other end side exposed from the support hole 39. 52a is integrally welded and fixed.
One end side of the brake operation shaft 52 inserted into the support hole 39 is in contact with the disk-shaped pressing body 78a of the brake 78, and presses the pressing body 78a toward the friction plate 78b. A pressing operation portion 54 is formed so that braking can be applied to 74.
As shown in FIGS. 9, 11, and 12, the pressing operation portion 54 is formed by cutting out the outer peripheral portion of the round rod-shaped brake operation shaft 52 into an L shape within a range corresponding to approximately ¼ rotation. The outer periphery of the shaft 52 is formed by providing a groove-shaped portion that is cut out in a state having two surfaces 54a and 54b extending along the axial direction and substantially perpendicular to each other.
As a result, one surface 54b of the concave groove-shaped portion having two surfaces 54a, 54b in a substantially orthogonal direction is positioned in contact with the rear surface side of the disc-shaped pressing body 78a of the brake 78, and the brake operation shaft 52 is moved. By rotating, one surface 54b of the concave groove-shaped portion presses the rear surface side of the pressing body 78a forward, and is configured to exert a braking action.

The pressing operation portion 54 is formed by cutting out the outer peripheral portion of the round rod-shaped brake operation shaft 52. Therefore, the cross-sectional diameter of the brake operation shaft 52 at the location where the pressing operation portion 54 is formed is within the range of the outer diameter of the round bar portion of the brake operation shaft 52. That is, the pressing operation part 54 exists in the range of the axial cross-sectional area in the location which the brake operation axis | shaft 52 penetrates the case wall of the transmission case 3 in the axial direction view of the brake operation axis | shaft 52.
Therefore, when the brake operation shaft 52 is moved in the insertion / extraction direction with respect to the support hole 39, it can be inserted / removed without requiring disassembly operation of the travel output shaft 74 or the brake 78.

As shown in FIGS. 2 and 10, the free end portion of the linkage arm portion 52a provided on the other end side of the brake operation shaft 52 is a linkage rod 55 (corresponding to a connecting member) having a turnbuckle 55a in the middle. Is connected to an operation arm 50e extending rearward from the cylindrical portion 50d of the brake pedal 50.
As a result, when the brake pedal 50 is depressed, the rear support rod 50c rotates the operation arm 50e around the pivot axis x1 of the pivot shaft 51 and pulls it upward. Along with this, the linkage rod 55 rotates the free end portion of the linkage arm portion 52a around the axis of the brake operation shaft 52 and pulls it upward.
At this time, in the pressing operation portion 54 of the brake operation shaft 52, the one surface 54b of the concave groove-shaped portion that contacts the rear surface side of the pressing body 78a of the brake 78 presses the pressing body 78a against the side where the friction plate 78b exists. It rotates to press the friction plate 78b of the brake 78, and a braking force is applied to the travel output shaft 74.
When the depression of the brake pedal 50 is released, the return spring 56 swings and returns the brake pedal 50 to the return side, and the brake operation shaft 52 linked to the linkage rod 55 also has the one surface 54 b of the pressing operation portion 54 of the brake 78. It reversely rotates to the side away from the rear surface side of the pressing body 78a, and the braking of the travel output shaft 74 is released.
An operation arm 50e extended from the cylindrical portion 50d of the brake pedal 50, a linkage arm portion 52a provided on the other end side of the brake operation shaft 52, and the manipulation arm 50e and the linkage arm portion 52a. The linkage mechanism 53 is configured by including the linkage rod 55 to be connected.

[Regulatory members]
A structure for restricting the brake operating shaft 52 from coming out of the support hole 39 will be described.
As shown in FIGS. 9 to 12, a hook-like portion 52 b (corresponding to an engaging portion) is integrally provided at an intermediate position in the axial direction of the brake operation shaft 52. The hook-shaped portion 52 b is located on the shaft portion exposed from the support hole 39 in a state where the end portion of the brake operation shaft 52 on the side where the pressing operation portion 54 exists is inserted into the support hole 39.

As shown in FIG. 11, the transmission case wall above the support hole 39 of the transmission case 3 is provided with a screw hole 39a, and the regulating member 57 can be fixed by a fixing bolt 58 screwed into the screw hole 39a. It is configured.
The restricting member 57 includes an arcuate curved concave portion 57 a along the outer peripheral surface of the brake operation shaft 52, and the curved concave portion 57 a is mounted so as to straddle the upper half of the brake operation shaft 52. A through hole 57b is provided in the upper part of the restricting member 57, and the restricting member 57 is fixed to the transmission case wall by inserting and fixing the fixing bolt 58 into the through hole 57b.

As shown in FIG. 12, when the regulating member 57 is fixed to the transmission case wall on both lateral sides of the place where the regulating member 57 exists with the fixing bolt 58, the lateral edge 57c of the regulating member 57 is contacted with the side edge 57c. In contact therewith, stopper portions 30c, 30c (corresponding to stoppers) for restricting further swinging of the regulating member 57 are provided. As shown by phantom lines in FIG. 12, the stopper portions 30c and 30c are arranged so that the inner peripheral edge of the curved recess 57a of the regulating member 57 is braked when the regulating member 57 swings in the right direction or the left direction. It is provided so that contact with the outer peripheral surface of the operation shaft 52 can be restricted.
Therefore, when the regulating member 57 is fixed to or released from the transmission case wall, the regulating member 57 rotates along with the tightening rotation of the fixing bolt 58 or the rotation in the loosening direction, and the curved recess 57a. The inner peripheral edge of the brake can be prevented from contacting the outer peripheral surface of the brake operation shaft 52. With this configuration, it is possible to avoid contact damage with the regulating member 57 on the outer peripheral surface of the brake operation shaft 52.

As shown in FIG. 10, the restricting member 57 is positioned on the vehicle body side in the left-right direction with respect to the main frame 10A, and the linkage arm portion 52a of the brake operation shaft 52 is on the vehicle body outer side in the left-right direction with respect to the main frame 10A. Is located.
By configuring in this way, the possibility that the regulating member 57 to be provided outside the mission case 3 comes into contact with other objects is minimized. During maintenance work such as when the brake operation shaft 52 is pulled out for inspection, the fixing by the restriction member 57 can be easily released by an external operation, and the vehicle body is outside the body in the left-right direction with respect to the main frame 10A. The outer end of the brake operation shaft 52 located on the side can be gripped and pulled out easily. Thus, the maintenance work can be simplified without the disassembly of the transmission case 3 and the disassembly work of the vehicle body frame 10.

[Back clutch operation]
As shown in FIG. 8, the main transmission lever 16 provided on the lateral side portion of the steering handle 15 is provided on the transmission path for transmitting power from the second transmission shaft 65 provided in the mission case 3 to the seedling planting device 2. A back clutch 100 is provided that releases power transmission in response to a swing operation toward the reverse shift position R.
The back clutch 100 is configured to be able to be engaged and disengaged by moving in the axial direction with respect to the work output gear 81 that is relatively rotatably provided on the lower transmission side of the second transmission shaft 65. When it comes close to the output gear 81, it engages and enters the clutch state, and transmits power to the seedling planting device 2. When moving away from the work output gear 81, the engagement is released and the clutch is disengaged, and the power transmission to the seedling planting device 2 is released.

A linkage mechanism 101 for linking the on / off operation of the back clutch 100 and the forward / reverse switching operation of the main transmission lever 16 is provided. The linkage mechanism 101 is configured as follows.
As shown in FIG. 14, the main speed change lever 16 among the operations of the main speed change lever 16 that swings back and forth in the guide groove 16 </ b> A and is swung to the forward shift position F side and the reverse shift position R side. A detection lever 102 (corresponding to detection means) for detecting an operation toward the reverse shift position R in contact with 16 is supported so as to be swingable about the vertical shaft 103.
The movement of the detection lever 102 toward the forward shift position F on the detection end 102a side is restricted by a stopper 104 provided in the driving portion 13 near the guide groove 16A. Therefore, the operation between the forward shift position F and the neutral position N of the main shift lever 16 is outside the range of detection by the detection lever 102.

An end portion 102b of the detection lever 102 opposite to the detection end 102a that has detected an operation toward the reverse shift position R side of the main transmission lever 16 is linked to a bell crank 106 via a connecting rod 105. The bell crank 106 is supported so as to be rotatable about a vertical axis 107, and has a long hole 106a for linking at the end opposite to the side connected to the connecting rod 105.
An upper and lower shaft 108 is provided at the upper part of the mission case 3 so as to be rotatable through the upper wall 30t of the mission case 3. A swing operation member 109 (corresponding to an interlocking arm) is integrally provided at the upper end of the vertical shaft 108. The swing operation member 109 is positioned on the upper side of the upper wall 30t of the mission case 3, and is configured such that a pin 109a provided at one end is engaged with the long hole 106a of the bell crank 106. The other end side of the swing operation member 109 is provided with an operation body 109b positioned inside the mission case 3 and positioned on the lower end side of the vertical shaft 108 that penetrates the upper wall 30t of the mission case 3.
Accordingly, as the bell crank 106 swings, the swing operating member 109 swings around the vertical shaft 108 through the elongated hole 106a and the pin 109a. As the swing operation member 109 swings around the vertical axis 108, the operation body 109 b on the other end side of the swing operation member 109 moves the back clutch 100 disposed in the mission case 3. It is configured to turn on and off.

  The upper and lower shafts 108 provided rotatably through the upper wall 30t of the mission case 3 are rotatably mounted on the upper wall 30t of the mission case 3 with a bush 110 fitted on the outer periphery thereof. Yes.

[Other Embodiment 1]
In the above embodiment, the operation of the steering handle 15 is transmitted to the torque generator 4 via the steering operation shaft 15a, and the output of the torque generator 4 is transmitted to the pitman arm 44 via the steering shaft 41. Although the thing was illustrated, it is not restricted to such a structure.
For example, the torque generator 4 is omitted, and the operation of the steering handle 15 is directly transmitted to the steering shaft 41, and the pitman arm 44 is operated in accordance with the operation of the steering shaft 41. May be.
Other configurations may be the same as those in the above-described embodiment.

[Second embodiment]
In the above-described embodiment, the transmission case 3 has a structure in which the split surface is constituted by the split case body of the case main body portion 30 and the lid-like case portion 31 that are divided in the left and right directions along the vertical direction. However, it is not limited to this structure. For example, it may have a structure in which the split surface is divided along the top and bottom in the left-right direction and divided into front and back, or the split surface is divided in the top and bottom along the horizontal direction.
Other configurations may be the same as those in the above-described embodiment.

[3 of another embodiment]
In the above-described embodiment, the regulating member 57 contacts the lateral edge 57c of the regulating member in both the rotation direction to the fixed side and the rotation direction when the fixation is released, and the inner periphery of the curved recess 57a of the regulating member 57 The stoppers 30c and 30c are illustrated as being provided on both lateral outer sides of the restricting member 57 so that the surfaces can be prevented from coming into contact with the outer peripheral surface of the brake operation shaft 52, but the present invention is not limited to this.
For example, the stopper portion 30c is placed on one side of the regulating member 57 so as to avoid contact between the inner peripheral surface of the curved concave portion 57a of the regulating member 57 and the outer circumferential surface of the brake operation shaft 52 in the rotation direction to the fixed side of the regulating member 57. The stopper member 30c is not provided on the other lateral outer side of the restricting member 57 so as not to restrain the movement of the restricting member 57 in the rotation direction of the restricting member 57 toward the unlocking side. There is no problem.
Other configurations may be the same as those in the above-described embodiment.

[4 of another embodiment]
In the above embodiment, the stopper portions 30c and 30c for restricting the swinging movement of the restriction member 57 are exemplified by a structure in which a part of the case wall also serves as the stopper portions 30c and 30c. An appropriate configuration such as providing a dedicated contact member can be adopted.
Other configurations may be the same as those in the above-described embodiment.

[5 of another embodiment]
In the above embodiment, the restricting member 57 is illustrated as having a structure in which the restricting member 57 is fixed to the transmission case wall via the single fixing bolt 58. However, the present invention is not limited to this. For example, the regulating member 57 may be formed in an annular shape and fixed with a plurality of fixing bolts 58 of two, upper and lower or left and right, or more.
Other configurations may be the same as those in the above-described embodiment.

[6 of another embodiment]
In the above-described embodiment, the engaging portion is configured by providing the outer peripheral surface of the brake operation shaft 52 with the hook-like portion 52b protruding outward, but the present invention is not limited to such a structure. . For example, the brake operation shaft 52 itself is configured by a stepped shaft having a shaft diameter on the end portion side farther from the pressing operation portion 54 than a shaft diameter on the side provided with the pressing operation portion 54 and inserted into the support hole 39. May be.
Other configurations may be the same as those in the above-described embodiment.

[7 of another embodiment]
In the above-described embodiment, the engagement portion is configured by providing the outer peripheral surface of the brake operation shaft 52 with the hook-shaped portion 52b that protrudes outward. The structure is not limited to the structure protruding outward from the outer peripheral surface of the operation shaft 52.
For example, a concave portion such as an annular groove is formed in the outer peripheral surface of the brake operation shaft 52, and the movement of the brake operation shaft 52 in the axial direction is restricted by a structure in which the restriction member 57 is engaged in the concave portion. May be.
Other configurations may be the same as those in the above-described embodiment.

[8 of another embodiment]
In the above embodiment, the structure in which the front support rod 50b, the rear support rod 50c, and the cylindrical portion 50d of the brake pedal 50 are configured with a circular cross section is illustrated, but the present invention is not limited to this. For example, a structure in which the contact portion between the front support rod 50b or the rear support rod 50c and the cylindrical portion 50d is deformed so as to be slightly flattened may be used. In this case, it is possible to omit the use of the connection plate 50f.
Other configurations may be the same as those in the above-described embodiment.

  The work vehicle to which the present invention is applied is not limited to a riding type rice transplanter, and may be other paddy working machines such as a walking type rice transplanting machine, a riding type direct seeding machine, and a walking type direct seeding machine. Not only a machine but various farming machines such as a tractor, a lawnmower, a transporter, etc. may be used.

DESCRIPTION OF SYMBOLS 2 Seedling planting device 3 Mission case 10 Body frame 10A Main frame 16 Shifting operation lever 16A Guide groove 22 Planting claw drive mechanism 30c Stopper 50 Brake pedal 50a Tread part 50e Operation arm 51 Pivoting shaft 52 Brake operation shaft 52a Portion 52b Engaging portion 54 Pressing operation portion 55 Connecting member 57 Restricting member 58 Fixing bolt 61 Hydrostatic continuously variable transmission 78 Brake 93 Planting clutch 100 Transmission clutch 101 Linking mechanism 102 Detection lever 109 Swing operation member x1 Pivot shaft Center F Forward shift position R Reverse shift position N Neutral position

Claims (15)

The brakes installed in the mission case,
A brake operating shaft for operating the brake from outside the transmission case;
A brake pedal for operating the brake operation shaft,
A work vehicle that is provided with a restricting member for restricting the brake operating shaft from slipping out of the mission case, and is configured to be switchable between a slip-out restricting state and a restriction releasing state. .   The work vehicle according to claim 1, wherein an engagement portion with the restriction member is formed on the brake operation shaft on the outside of the transmission case.   A portion of the brake operation shaft that is inserted inside the mission case is operated to rotate the brake operation shaft around the axis of the brake operation shaft to release and release the brake installed in the mission case. A pressing operation portion for switching to a state, and the pressing operation portion is a shaft at a location where the brake operation shaft penetrates the case wall of the transmission case as viewed in the axial direction of the brake operation shaft. The work vehicle according to claim 1 or 2, wherein the work vehicle is formed within a range of a cross-sectional area.   The work vehicle according to claim 1, wherein the restriction member is configured to be detachable from the mission case.   The work vehicle according to claim 4, wherein the restricting member is configured to be detachable by a near-far movement in a radial direction with respect to the brake operation shaft.   The work vehicle according to claim 1, wherein the restriction member is configured to be connected and fixed to a case wall of the transmission case with a fixing bolt.   The fixing bolt is a single bolt, and is configured to regulate the radial movement of the restricting member relative to the brake operation shaft and the separation of the restricting member from the case wall of the transmission case. The work vehicle according to claim 6.   The restricting member is configured to be able to swing within a predetermined range around the axis of the fixing bolt in a state where the fastening and fixing by the fixing bolt is not completed. A stopper to be set is provided, and the swingable range by the stopper is set to a range in which the regulating member swung around the axis of the fixing bolt can be prevented from coming into contact with the outer peripheral surface of the brake operation shaft. The work vehicle according to claim 7.   The work vehicle according to claim 8, wherein the stopper is provided at both ends of a swingable range of the regulating member.   The work vehicle according to claim 8 or 9, wherein the stopper is constituted by a part of the mission case.   A projecting end portion of the brake operation shaft to the outer side of the transmission case extends to the outside of the main frame long in the front-rear direction provided in the vehicle body frame, and the extension end portion is linked to the brake pedal. The work vehicle according to any one of claims 1 to 10, wherein the work arm is mounted in a state of being located outside the main frame.   The brake pedal is provided so as to be swingable around a lateral pivot axis that intersects the longitudinal direction of the main frame, and the tread surface of the brake pedal is directed to the opposite side across the pivot axis. The work vehicle according to claim 11, wherein the arm portion is linearly extended in a direction intersecting the pivot axis, and the arm portion and the linking arm portion of the brake operation shaft are connected. The brakes installed in the mission case,
A brake operating shaft for operating the brake from outside the transmission case;
A brake pedal for operating the brake operation shaft,
A regulation member that regulates the brake operation shaft from slipping out of the mission case is equipped outside the mission case, and the regulation member is configured to be switchable between a slip-out regulation state and a regulation release state.
The brake operating shaft is formed with an engaging portion with the regulating member on the outside of the mission case,
A portion of the brake operation shaft that is inserted inside the mission case is operated to rotate the brake operation shaft around the axis of the brake operation shaft to release and release the brake installed in the mission case. A pressing operation portion for switching to a state, and the pressing operation portion is a shaft at a location where the brake operation shaft penetrates the case wall of the transmission case as viewed in the axial direction of the brake operation shaft. Formed within the cross-sectional area,
The work vehicle is configured such that the restriction member is detachable from the mission case. The brakes installed in the mission case,
A brake operating shaft for operating the brake from outside the transmission case;
A brake pedal for operating the brake operation shaft,
A regulation member that regulates the brake operation shaft from slipping out of the mission case is equipped outside the mission case, and the regulation member is configured to be switchable between a slip-out regulation state and a regulation release state.
The brake operating shaft is formed with an engaging portion with the regulating member on the outside of the mission case,
A portion of the brake operation shaft that is inserted inside the mission case is operated to rotate the brake operation shaft around the axis of the brake operation shaft to release and release the brake installed in the mission case. A pressing operation portion for switching to a state, and the pressing operation portion is a shaft at a location where the brake operation shaft penetrates the case wall of the transmission case as viewed in the axial direction of the brake operation shaft. Formed within the cross-sectional area,
The restricting member is configured to be attachable and detachable with a distance movement in a radial direction with respect to the brake operation shaft, and to be connected and fixed to a case wall of the transmission case with a single fixing bolt,
The restricting member is configured to be able to swing within a predetermined range around the axis of the fixing bolt in a state where the fastening and fixing by the fixing bolt is not completed. A stopper to be set is provided, and the swingable range by the stopper is set to a range in which the regulating member swung around the axis of the fixing bolt can be prevented from coming into contact with the outer peripheral surface of the brake operation shaft. ,
The stopper is provided at both ends of a swingable range of the regulating member, and is a work vehicle configured by a part of the transmission case. The brakes installed in the mission case,
A brake operating shaft for operating the brake from outside the transmission case;
A brake pedal for operating the brake operation shaft,
A regulation member that regulates the brake operation shaft from slipping out of the mission case is equipped outside the mission case, and the regulation member is configured to be switchable between a slip-out regulation state and a regulation release state.
The brake operating shaft is formed with an engaging portion with the regulating member on the outside of the mission case,
A portion of the brake operation shaft that is inserted inside the mission case is operated to rotate the brake operation shaft around the axis of the brake operation shaft to release and release the brake installed in the mission case. A pressing operation portion for switching to a state, and the pressing operation portion is a shaft at a location where the brake operation shaft penetrates the case wall of the transmission case as viewed in the axial direction of the brake operation shaft. Formed within the cross-sectional area,
The restricting member is configured to be attachable and detachable with a distance movement in a radial direction with respect to the brake operation shaft, and to be connected and fixed to a case wall of the transmission case with a single fixing bolt,
The restricting member is configured to be able to swing within a predetermined range around the axis of the fixing bolt in a state where the fastening and fixing by the fixing bolt is not completed. A stopper to be set is provided, and the swingable range by the stopper is set to a range in which the regulating member swung around the axis of the fixing bolt can be prevented from coming into contact with the outer peripheral surface of the brake operation shaft. ,
The stopper is provided on both ends of the swingable range of the restricting member, and is configured by a part of the mission case.
A projecting end portion of the brake operation shaft to the outer side of the transmission case extends to the outside of the main frame long in the front-rear direction provided in the vehicle body frame, and the extension end portion is linked to the brake pedal. Equipped with the arm part positioned outside the main frame,
The brake pedal is provided so as to be swingable around a lateral pivot axis that intersects the longitudinal direction of the main frame, and the tread surface of the brake pedal is directed to the opposite side across the pivot axis. A working vehicle in which the arm portion extends in a direction orthogonal to the pivot axis, and the arm portion and the linkage arm portion of the brake operation shaft are connected.

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