JP6787012B2 - Work vehicle - Google Patents

Description

The present invention relates to a work vehicle.

Conventionally, in a work vehicle such as a seedling transplanter used for planting seedlings in a field, it has been known that an auxiliary wheel can be attached in order to improve running performance in the field (). For example, see Patent Document 1).

Japanese Unexamined Patent Publication No. 2014-108080

In a work vehicle, for example, the wheels may be turned upside down and attached to a traveling vehicle body depending on the work content and the difference in the model of the machine body.

However, in the above-mentioned conventional work vehicle, it is not considered to turn the wheels upside down, and if the wheels are turned upside down, the auxiliary wheels cannot be attached.

The present invention has been made in view of the above, and an object of the present invention is to provide a work vehicle to which auxiliary wheels can be attached when the wheels are turned upside down.

In order to solve the above-mentioned problems and achieve the object, the work vehicle according to claim 1 includes a shaft portion (14) extending in the left-right direction of the traveling vehicle body (2) and transmitting a driving force. A traveling wheel (11) that can be mounted on the shaft portion (14) by inverting the front and back by the mounting portion (115) extending in the left-right direction, and a housing portion (132) that can accommodate the mounting portion (115). ), Which is attached to the flange portion (116) of the traveling wheel (11) regardless of the mounting direction of the traveling wheel (11), and extends in the left-right direction, and the extension portion (13). It is characterized by including an auxiliary wheel (12) attached to the tip of the portion (13).

The work vehicle according to claim 2 is the work vehicle according to claim 1, wherein the extension portion (13) is a fixing portion (15a, 15b) for fixing the traveling wheel (11) to the shaft portion (14). ), And a cover (133e) protruding outward in the radial direction is provided.

The work vehicle according to claim 3 is the work vehicle according to claim 1 or 2, wherein the accommodating portion (132) has a fixed portion (11) for fixing the traveling wheel (11) to the shaft portion (14). It is characterized in that a visual hole (133b) is formed so that the 15a and 15b) can be visually recognized from the outside.

The work vehicle according to claim 4 is the work vehicle according to claim 3, wherein the extension portion (13) is thicker than the other accommodating portion (132) around the visual recognition hole (133b). It is characterized by having a thick portion (133d).

The work vehicle according to claim 5 is the work vehicle according to claims 1 to 4, wherein the accommodating portion (132) is formed with a discharge hole (133f) for discharging mud that has entered the inside. It is a feature.

The work vehicle according to claim 6 is the work vehicle according to any one of claims 1 to 5, wherein the flange portion (11) of the traveling wheel (11) is attached regardless of the mounting direction of the traveling wheel (11). It is characterized by providing a reinforcing plate (16, 160) that can be arranged on the back surface of the 116).

The work vehicle according to claim 7 is the work vehicle according to any one of claims 1 to 6, which is extended in the vertical direction of the traveling vehicle body (2) and transmits a driving force to the front wheels (5). The traveling transmission shaft (33) that moves up and down together with the front wheel (5), the suspension mechanism (29) provided around the traveling transmission shaft (33), the traveling transmission shaft (33), and the suspension mechanism ( A case (22) accommodating the 29) and having a recess (22d) recessed upward on the upper end inner wall, and an adjusting portion (22) capable of adjusting the internal pressure of the case (22) via the recess (22d). 30) is provided.

The work vehicle according to claim 8 is the work vehicle according to claim 7, wherein the adjustment unit (30) is a breather (30) communicating with the recess (22d).

According to the work vehicle according to claim 1, by providing an accommodating portion capable of accommodating the mounting portion in the extension portion, the extension portion can be attached to the flange portion of the traveling wheel regardless of the mounting direction of the traveling wheel. it can.

According to the work vehicle according to claim 2, in addition to the effect of the invention according to claim 1, the fixing portion for fixing the traveling wheel to the shaft portion is covered, and a cover protruding outward in the radial direction is provided. It is possible to prevent mud from entering the extension.

According to the work vehicle according to claim 3, in addition to the effect of the invention according to claim 1 or 2, the accommodating portion is provided with a visible hole for visually recognizing the fixing portion between the traveling wheel and the shaft portion. , The state of the fixed portion, for example, the looseness of the fixed portion can be easily confirmed.

According to the work vehicle according to claim 4, in addition to the effect of the invention according to claim 3, the strength of the extension portion can be increased by thickening the periphery of the viewing hole.

According to the work vehicle according to claim 5, in addition to the effect of the invention according to any one of claims 1 to 4, the inside of the extension portion is formed by forming a discharge hole for discharging mud in the accommodating portion. The mud that has invaded the area can be discharged.

According to the work vehicle according to claim 6, in addition to the effect of the invention according to any one of claims 1 to 5, the strength of the traveling wheel is increased by providing a reinforcing plate on the back surface of the traveling wheel. be able to.

According to the work vehicle according to claim 7, in addition to the effect of the invention according to any one of claims 1 to 6, on the upper upper inner wall of the case accommodating the traveling transmission shaft of the front wheels and the suspension mechanism. By providing a recess that is recessed upward and making it possible to adjust the internal pressure of the case through the recess, it is possible to adjust the responsiveness when the suspension mechanism contracts.

According to the work vehicle according to claim 8, in addition to the effect of the invention according to claim 7, the responsiveness of the suspension mechanism can be easily adjusted by providing the breather communicating with the recess.

FIG. 1 is a side view of the seedling transplanter according to the first embodiment. FIG. 2 is a plan view of the seedling transplanter according to the first embodiment. FIG. 3 is a perspective view of a handrail provided on the right side of the traveling vehicle body. FIG. 4 is an explanatory diagram of a spare seedling frame. FIG. 5 is a view taken along the line AA of FIG. FIG. 6 is an enlarged cross-sectional view showing a part of the front wheel final case of FIG. FIG. 7 is a cross-sectional view of the rear wheels as viewed from above. FIG. 8 is a perspective view of the auxiliary rear wheel mounting portion. FIG. 9 is a front view of the auxiliary rear wheel mounting portion as viewed from the auxiliary rear wheel side. FIG. 10 is a schematic view of the backup plate. FIG. 11 is a cross-sectional view of the rear wheel according to the second embodiment as viewed from above. FIG. 12 is a cross-sectional view of the rear wheel according to the third embodiment as viewed from above. FIG. 13 is a plan view of the extension portion according to the fourth embodiment. FIG. 14 is a front view of the extension portion according to the fourth embodiment as viewed from the auxiliary rear wheel side. FIG. 15 is a schematic view of a backup plate of a modified example. FIG. 16 is a schematic view of a backup plate of a modified example. FIG. 17 is a schematic view showing a state in which the cockpit is rotated forward.

The work vehicle according to the embodiment will be described in detail below with reference to the drawings. Here, a seedling transplanter will be described as an example as a work vehicle. The present invention is not limited to the following embodiments. In addition, the components in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same, that is, those having a so-called equal range. In addition, the components in the following embodiments can be combined as appropriate.

[First Embodiment]
FIG. 1 is a side view of the seedling transplanter 1 according to the first embodiment. FIG. 2 is a plan view of the seedling transplanter 1 according to the first embodiment. In the following description, the front-rear, left-right, and up-down directions are defined as front-back, left-right, and up-down with reference to the traveling direction of the vehicle body when viewed from the driver's seat 55. Further, in the left-right direction, the outside of the seedling transplanter 1 will be described as the outside in the left-right direction.

The traveling vehicle body 2 of the seedling transplanter 1 has a front wheel 5 arranged in a pair on the left and right, and a rear wheel 10 similarly arranged in a pair on the left and right, and a four-wheel drive in which each wheel is driven during traveling. It is a car. Further, the front wheels 5 are located on the front side of the rear wheels 10 and are provided as steering wheels. Further, the rear portion of the traveling vehicle body 2 is provided with a seedling planting portion 60 that can be raised and lowered by the seedling planting portion raising and lowering mechanism 70.

The traveling vehicle body 2 transmits the power generated by the main frame 3 arranged substantially in the center of the vehicle body, the engine 20 mounted on the main frame 3, and the engine 20 to the drive wheels and the seedling planting unit 60. It includes a power transmission device 25. That is, in the rice transplanter 1, the power of the engine 20, which is a power source, is used not only to move the traveling vehicle body 2 forward and backward, but also to drive the seedling planting unit 60, and is used for a diesel engine and gasoline. A heat engine such as an engine is used.

The engine 20 is arranged at substantially the center of the traveling vehicle body 2 in the left-right direction and in a state of projecting upward from the floor step 40, which is a boarding step of the aircraft. Further, the floor step 40 is provided between the front portion of the traveling vehicle body 2 and the rear portion of the engine 20, and is mounted on the main frame 3. The floor step 40 is partially meshed so that mud attached to the shoes can be removed into the field. Further, on both sides of the floor step 40 in the left-right direction, boarding / alighting steps 45 on which an operator puts his / her feet when getting on / off the floor step 40 are arranged.

Further, behind the floor step 40, a rear step 47 that also serves as a fender for the rear wheels 10 is provided. The rear step 47 is arranged at a position higher than the floor step 40, and is arranged from the left and right sides of the engine 20 to the rear. Further, handrails 48 are arranged from the rear end portion to both side end portions of the rear step 47. The handrail 48 is provided so as to project upward from the rear step 47.

As shown in FIG. 3, the handrail 48 is composed of a seat portion 48a and a backrest portion 48b. FIG. 3 is a perspective view of the handrail 48 provided on the right side of the traveling vehicle body 2. The backrest portion 48b is arranged above the seat portion 48a, and is formed so that the central portion in the front-rear direction is curved so as to project outward in the left-right direction.

It is also possible to arrange a plate-shaped member on the upper part of the backrest portion 48b and use it as a seedling holder.

Returning to FIGS. 1 and 2, the engine 20 projects upward from the floor step 40 and the rear step 47, and an engine cover 21 covering the engine 20 is provided at a portion protruding from the steps 40 and 47. It is arranged. That is, the engine cover 21 covers the engine 20 in a state of protruding upward from the floor step 40 and the rear step 47.

The driver's seat 55 is installed in the upper part of the engine cover 21 of the traveling vehicle body 2, and the steering unit 50 is arranged in front of the driver's seat 55 and in the front central portion of the traveling vehicle body 2. The control unit 50 is arranged so as to project upward from the floor surface of the floor step 40.

Various operating devices, fuel tanks for engine fuel, and the like are arranged inside the control unit 50, and a front cover 51 that can be opened and closed is provided at the front portion of the control unit 50. Further, an operation lever or the like for operating the operation device, instruments, and a handle 52 are arranged on the upper part of the control unit 50.

The steering wheel 52 is provided as a steering member for steering the traveling vehicle body 2 by the operator steering the front wheels 5, and the front wheels 5 can be steered via an operating device or the like in the control unit 50. It has become. Further, as the lever (not shown), at least the seedling planting portion elevating mechanism 70 is used to determine the operating state of the speed change lever, which is a traveling operation member for operating the traveling vehicle body 2 forward / backward movement and the traveling speed, and the seedling planting portion 60. A planting elevating lever, which is a planting operation member that can be switched including the ascending state, is provided.

FIG. 4 is an explanatory diagram of the spare seedling frame 90. FIG. 5 is a view taken along the line AA of FIG. Spare seedling frames 90 for loading supplementary seedlings are arranged on the left and right side portions of the control unit 50 in the floor step 40, that is, on the front side of the machine body.

The spare seedling frame 90 is provided so that the outer end portion does not protrude from the outer end portion of the floor step 40 of the aircraft in the left-right direction, and is supported by the support shaft 91 protruding from the floor surface of the floor step 40. ing. The support shaft 91 is connected to the spare seedling frame 90 near the center of the spare seedling frame 90 in the front-rear direction.

The power transmission device 25 includes a hydraulic continuously variable transmission 26 as a main transmission that shifts the power generated by the engine 20, and a belt-type power transmission mechanism 27 that transmits the power from the engine 20 to the hydraulic continuously variable transmission 26. And have. Of these, the hydraulic continuously variable transmission 26 is configured as a hydrostatic continuously variable transmission called an HST (Hydr Static Transmission). Therefore, the hydraulic continuously variable transmission 26 generates flood control by a hydraulic pump driven by power from the engine 20, and converts the generated flood control into mechanical force (rotational force) by a hydraulic motor and outputs it. ..

The hydraulic continuously variable transmission 26 is arranged in front of the engine 20 and below the floor surface of the floor step 40, and is arranged in front of the engine 20 when viewed from the upper surface of the traveling vehicle body 2. There is.

The belt-type power transmission mechanism 27 includes a pulley attached to the output shaft of the engine 20, a pulley attached to the input shaft of the hydraulic continuously variable transmission 26, a belt wound around both pulleys, and a tension of the belt. It is equipped with a tension pulley to adjust. As a result, the belt-type power transmission mechanism 27 can transmit the power generated by the engine 20 to the hydraulic continuously variable transmission 26 via the belt.

The power transmission device 25 has a mission case 28 in which the output from the engine 20 is transmitted via the belt type power transmission mechanism 27 and the hydraulic continuously variable transmission 26. The mission case 28 is attached to the front portion of the main frame 3. The transmission case 28 shifts the output from the engine 20 transmitted via the belt-type power transmission mechanism 27 and the hydraulic continuously variable transmission 26 by the auxiliary transmission in the transmission case 28, and shifts the output to the front wheels 5 and the rear. The power for traveling to the wheel 10 and the power for driving the seedling planting portion 60 can be output separately.

Of these, part of the running power can be transmitted to the front wheels 5 via the left and right front wheel final cases 22, and the rest to the rear wheels 10 via the left and right rear wheel gear cases 23 (see FIG. 7). It can be transmitted. On the other hand, the driving power is transmitted to the planting clutch (not shown) provided at the rear of the traveling vehicle body 2, and is transmitted to the seedling planting portion 60 by the planting transmission shaft (not shown) when the planting clutch is engaged. Will be done.

As shown in FIG. 6, the front wheel final case 22 accommodates a suspension mechanism 29 for absorbing the vertical movement of the front wheel 5 due to the unevenness of the field. FIG. 6 is an enlarged cross-sectional view showing a part of the front wheel final case 22 of FIG.

The front wheel final case 22 has an upper case 22a and a lower case 22b.

The upper case 22a is configured by attaching the lid portion 22c to the opening formed at the upper end. The lid portion 22c is formed with a recess 22d that is recessed upward. The recess 22d communicates with the outside via the breather 30.

The suspension mechanism 29 includes an upper spring receiving portion 29a rotatably supported by a bearing 31a provided on the upper case 22a and a lower spring receiving portion 29b rotatably supported by a bearing 31b provided on the lower case 22b. A spring 29c is arranged between the springs 29c.

The spring 29c is arranged outside the driven shaft 33 spline-coupled to the upper driven bevel gear 32b that meshes with the upper driving bevel gear 32a. The upper driven bevel gear 32b is formed with a through hole into which the driven shaft 33 is inserted, and a spline groove is formed on the inner wall forming the through hole.

The driven shaft 33 is extended in the vertical direction. The driven shaft 33 is spline-coupled to the upper driven bevel gear 32b to transmit a driving force and rotate together with the upper driven bevel gear 32b. The driven shaft 33 is slidable in the vertical direction with respect to the upper driven bevel gear 32b, and moves up and down together with the front wheels 5 according to the unevenness of the field. A washer 33a is attached to the upper end of the driven shaft 33 by a bolt 33b. The washer 33a comes into contact with the lid 22c when the driven shaft 33 moves upward, and functions as a stopper that defines the upper limit position of the driven shaft 33.

In the front wheel final case 22 having the above configuration, when the driven shaft 33 moves to the upper limit position, a bag-shaped space is formed by the recess 22d and the washer 33a, and functions as an air cushion. Therefore, for example, when the front wheel 5 rides on the convex portion of the field, it is possible to prevent a sudden push-up from occurring.

Further, the responsiveness of the suspension mechanism 29 can be improved by discharging the air in the recess 22d to the outside by the breather 30. The responsiveness of the suspension mechanism 29 can be adjusted by adjusting the diameter and length of the breather 30. Further, an adjusting valve or the like may be provided between the breather 30 and the recess 22d.

Returning to FIGS. 1 and 2, the seedling planting section elevating mechanism 70 for raising and lowering the seedling planting section 60 provided at the rear of the traveling vehicle body 2 has an elevating link device 71, and the seedling planting section 60 has an elevating link device 71. , It is attached to the traveling vehicle body 2 via the elevating link device 71.

The elevating link device 71 has two members extending substantially in the front-rear direction, and is located below the upper link 73, which is an upper link member located relatively upward, and below the upper link 73. It has a lower link 74, which is a lower link member. A pair of left and right upper links 73 and a pair of lower links 74 are provided.

In the elevating link device 71, the upper link 73 and the lower link 74 are rotatably connected to the link base frame 75, which is a rear view gate type rear frame erected at the rear end of the main frame 3, and each link is connected. Since the other end side is rotatably connected to the seedling planting portion 60, the seedling planting portion 60 is movably connected to the traveling vehicle body 2. That is, the link base frame 75 is arranged so as to extend in the vertical direction at the rear portion of the traveling vehicle body 2, and the upper link 73 and the lower link 74 extend rearward from the link base frame 75. There is. In the elevating link device 71, both the upper link 73 and the lower link 74 are rotatably connected to the link base frame 75 on the front end side.

The seedling planting portion elevating mechanism 70 has a hydraulic elevating cylinder 76 that expands and contracts by flood control, and the seedling planting portion 60 can be elevated and lowered by the expansion and contraction operation of the hydraulic elevating cylinder 76. The seedling planting section elevating mechanism 70 can raise the seedling planting section 60 to a non-working position or lower it to a ground working position (ground planting position) by the raising / lowering operation.

The seedling planting unit 60 can plant the seedlings in a plurality of sections or a plurality of rows. That is, the seedling planting section 60 has a configuration in which seedlings can be planted with a plurality of rows.

The seedling planting section 60 includes a planting device 61, a seedling placing stand 65, and a float 81. Of these, the seedling placing table 65 is configured so that seedlings to be planted in the field can be placed. The seedling placing table 65 has as many seedling placing surfaces 66 as the number of planting rows partitioned in the left-right direction of the traveling vehicle body 2, and mat-shaped seedlings with soil are placed on each seedling placing surface 66. Is possible. As a result, every time the seedlings placed on the seedling stand 65 are planted and disappear, it is not necessary to return to pick up the seedlings prepared outside the field, and continuous work can be performed, so that the work efficiency is improved.

The planting device 61 is a device for planting seedlings placed on the seedling stand 65 in the field. The planting device 61 is arranged one by two for every two rows, and includes two row of planting rods 62. The planting rod 62 is configured so that seedlings can be taken from the seedling stand 65 and planted for each row.

The float 81 is arranged in the lower part of the seedling placing table 65, and is provided so that the ground can be leveled by sliding and leveling on the field scene as the traveling vehicle body 2 moves.

The float 81 detects the depth of the field by a detection member (not shown) such as a potentiometer that detects the rotation angle while leveling the unevenness of the field in the central part in the left-right direction of the machine, and seedlings are adjusted to the depth of the field. If it is composed of a main float that has the function of raising and lowering the planting part 60 and left and right side floats that slide and level the field scene where seedlings are planted on both the left and right sides of the main float, it automatically adapts to changes in the depth of the field. It is possible to adjust the planting depth of the seedlings to improve the planting accuracy of the seedlings.

Further, the float 81 constitutes a planting depth adjusting device 80 for adjusting the planting depth of the seedlings to be planted by the seedling planting unit 60. In other words, the float 81 has a planting depth adjusting device 80. doing. The planting depth adjusting device 80 can adjust the planting depth of the seedlings by adjusting the position of the seedling planting portion 60 in the vertical direction with respect to the field, and the float 81 and the float 81 in the vertical direction can be adjusted. By adjusting the position relative to the seedling planting portion 60, the vertical position of the seedling planting portion 60 with respect to the field can be adjusted.

Next, the rear wheel 10 will be described with reference to FIG. 7. FIG. 7 is a cross-sectional view of the rear wheel 10 as viewed from above.

The rear wheel 10 has a main rear wheel 11 attached to a rear wheel shaft 14 extending in the left-right direction of the traveling vehicle body 2, and an auxiliary rear wheel 12 attached to the main rear wheel 11 via an extension portion 13. The driving force is transmitted to the rear wheels 10 via the rear wheel gear case 23. The extension portion 13 and the auxiliary rear wheel 12 are removable from the main rear wheel 11.

A mounting hole 14a for mounting the main rear wheel 11 is formed in the rear wheel shaft 14 along the radial direction. Two mounting holes 14a are formed side by side in the left-right direction. In this way, by providing the rear wheel shaft 14 with a plurality of mounting holes 14a, the mounting position of the main rear wheel 11 can be changed in the left-right direction. The number of mounting holes 14a is not limited to two, and may be, for example, three or more. A washer 14b for preventing the main rear wheel 11 from falling off is fixed to the tip of the rear wheel shaft 14 by a bolt 14c.

The main rear wheel 11 can be attached to the rear wheel shaft 14 by turning it upside down. That is, the main rear wheel 11 can be attached to the rear wheel shaft 14 by changing the position in the axial direction (left-right direction) of the rear wheel shaft 14, and further, the front and back are inverted to the rear wheel shaft 14. On the other hand, the rear wheel shaft 14 can be attached by changing its position in the axial direction.

Therefore, the main and rear wheels 11 can change the distance (tread) between the pair of main and rear wheels 11. The main rear wheel 11 is attached to and fixed to the rear wheel shaft 14 by a push bolt 15a and a double nut 15b.

The main rear wheel 11 has a hub 110, a rim 111 (see FIG. 1) arranged radially outside the hub 110, and spokes 112 connecting the rim 111 and the hub 110. The main rear wheel 11 is arranged coaxially with the rear wheel shaft 14.

On the rim 111, lugs 113 (see FIG. 1) having a width wider than that of the rim 111 are formed at predetermined intervals along the circumferential direction. Further, three spokes 112 are arranged at intervals of 120 ° along the circumferential direction.

The hub 110 has a rear wheel shaft mounting portion 115 and a flange portion 116.

The rear wheel shaft mounting portion 115 extends along the left-right direction and is formed in a cylindrical shape. The rear wheel shaft mounting portion 115 is inserted into the rear wheel shaft 14. A through hole 115a into which a push bolt 15a for fixing the main rear wheel 11 to the rear wheel shaft 14 is inserted is formed in the rear wheel shaft mounting portion 115 along the radial direction. The ends of the spokes 112 are connected to the rear wheel shaft mounting portion 115.

The flange portion 116 is formed between the spokes 112, and connects the two spokes 112 and the rear wheel shaft mounting portion 115 on the inner side in the radial direction. That is, the flange portion 116 is formed so as to extend radially outward between the two spokes 112 from the outer peripheral wall of the rear wheel shaft mounting portion 115. In this way, the flange portions 116 are formed at three locations.

The flange portion 116 is also a mounting surface on which the extension portion 13 is mounted. The flange portion 116 is formed with a plurality of through holes 116a through which bolts 17a used when attaching the extension portion 13 to the flange portion 116 penetrate.

The main rear wheel 11 is formed so that the extension portion 13 can be attached even when the main rear wheel 11 is attached to the rear wheel shaft 14 by turning it upside down. Specifically, even when the main rear wheel 11 is turned upside down, the through hole 116a is formed so that the relative position of the through hole 116a with respect to the rotation axis of the rear wheel shaft 14 does not change.

The thickness of the flange portion 116 may be the same as the length of the spokes 112 in the left-right direction. As a result, when the main rear wheel 11 is turned upside down and attached to the rear wheel shaft 14, the extension portion 13 can be easily attached.

The extension portion 13 has an auxiliary rear wheel mounting portion 130 and an auxiliary shaft 131.

The auxiliary rear wheel mounting portion 130 will be described with reference to FIGS. 8 and 9 in addition to FIG. FIG. 8 is a perspective view of the auxiliary rear wheel mounting portion 130. FIG. 9 is a front view of the auxiliary rear wheel mounting portion 130 as viewed from the auxiliary rear wheel 12 side.

The auxiliary rear wheel mounting portion 130 includes a first cover 132 capable of accommodating a part of the rear wheel shaft 14 and a part of the rear wheel shaft mounting portion 115, and a second cover 133 accommodating a part of the spokes 112. It has a mounting portion 134 for mounting the auxiliary rear wheel mounting portion 130 to the flange portion 116 of the hub 110. The auxiliary rear wheel mounting portion 130 is a casting formed by casting.

The first cover 132 extends along the left-right direction and is formed in a cylindrical shape. The first cover 132 is formed with a reduced diameter toward the outside in the left-right direction. In the first cover 132, when the main rear wheel 11 is attached to the rear wheel shaft 14 so that the rear wheel shaft attachment portion 115 of the main rear wheel 11 projects outward in the left-right direction, the rear wheel shaft attachment portion 115 is attached. It is formed so as not to hit the inner wall of the first cover 132.

A recess 132a extending in the left-right direction is formed on the outer wall of the first cover 132. The recess 132a is formed so that the extension portion 13 can be easily attached by the bolt 17a and the nut 17b. Three recesses 132a are formed at intervals of 120 ° in the circumferential direction.

The second cover 133 is formed so as to cover the spokes 112 on the outer side in the left-right direction, and extends outward in the radial direction from the outer wall of the first cover 132. The second cover 133 is formed according to the number of spokes 112. In addition, the second cover 133 has a protruding portion 133a that projects outward in the left-right direction as it becomes inward in the radial direction. The protrusion 133a is a rib having a substantially U-shaped cross section perpendicular to the axis of the spoke 112. By providing the protruding portion 133a, the strength of the extension portion 13 can be increased.

Further, when the rear wheel shaft mounting portion 115 of the main rear wheel 11 is mounted on one of the protruding portions 133a of the three second cover 133 in a state of being housed in the first cover 132. That is, when the main rear wheel 11 is attached to the rear wheel shaft 14 with the rear wheel shaft mounting portion 115 facing outward in the left-right direction, a viewing hole 133b for visually recognizing the push bolt 15a or the double nut 15b is formed. To.

By providing the viewing hole 133b, the push bolt 15a or the double nut 15b does not hit the inner wall of the protruding portion 133a of the second cover 133, and the extension portion 13 can be attached to the main rear wheel 11. Further, when the extension portion 13 is attached to the main rear wheel 11, it also serves as a guide for the attachment position.

Around the viewing hole 133b, another portion, for example, a protruding portion 133a in which the viewing hole 133b is not formed and a thick portion 133d thicker than the wall thickness of the second cover 133 other than the protruding portion 133a are formed. As a result, it is possible to prevent the strength around the viewing hole 133b from being lowered.

Further, a recess 133c extending in the left-right direction is formed on the outer wall of the second cover 133. The recess 133c is formed so that the extension portion 13 can be easily attached by the bolt 17a and the nut 17b. Further, by forming the recess 133c, the strength of the extension portion 13 can be increased. Two recesses 133c are formed for each second cover 133.

The mounting portion 134 is formed between the two second covers 133, and connects the left-right inner ends of the two second covers 133 and the left-right inner ends of the first cover 132. The mounting portions 134 are formed at three locations so as to face the flange portions 116. The mounting portion 134 is formed in a plate shape. Each mounting portion 134 is formed with three through holes 134a into which bolts 17a are inserted. The mounting portion 134 is formed so that the extension portion 13 can be received by the flange portion 116 even when the main and rear wheels 11 are turned upside down.

Returning to FIG. 7, the auxiliary shaft 131 is formed from steel bars such as S45C and SCM. The auxiliary shaft 131 is welded to the tip of the first cover 132 of the auxiliary rear wheel mounting portion 130, and projects outward in the left-right direction. The auxiliary rear wheel 12 is attached to the auxiliary shaft 131.

The extension portion 13 described above abuts the mounting portion 134 on the surface (outer surface in the left-right direction) of the flange portion 116, and the backup plate 16 is brought into contact with the back surface of the flange portion 116 (inside in the left-right direction, that is, the surface on the traveling vehicle body 2 side). Is attached to the main and rear wheels 11 using bolts 17a and nuts 17b in a state of being in contact with each other.

The backup plate 16 is formed, for example, according to the shape of the mounting portion 134, and is formed so as to be displaceable between the two spokes 112 and the rear wheel shaft mounting portion 115. As shown in FIG. 10, the backup plate 16 is formed with three through holes 16a into which bolts 17a are inserted. FIG. 10 is a schematic view of the backup plate 16. In this embodiment, three backup plates 16 are used. The backup plate 16 is formed so that the extension portion 13 can be received by the flange portion 116 even when the main and rear wheels 11 are turned upside down. By providing the backup plate 16, the strength can be increased.

Returning to FIG. 7, the auxiliary rear wheel 12 has a hub 120, a rim 121 (see FIG. 1) arranged radially outside the hub 120, and spokes 122 connecting the rim 121 and the hub 120. The auxiliary rear wheel 12 is arranged coaxially with the rear wheel shaft 14.

On the rim 121, lugs 123 (see FIG. 1), which are wider than the rim 121, are formed at predetermined intervals along the circumferential direction. Further, three spokes 122 are arranged at intervals of 120 ° along the circumferential direction.

The auxiliary rear wheel 12 is formed so as to have the same diameter as the main rear wheel 11, and is attached to the auxiliary shaft 131 via the hub 120. The auxiliary rear wheel 12 is configured to be integrated with the auxiliary shaft 131 of the extension portion 13.

Next, the effect of the first embodiment will be described.

By providing the extension portion 13 with a first cover 132 capable of accommodating the rear wheel shaft mounting portion 115 of the main rear wheel 11, the extension portion 13 can be attached to the main rear wheel even when the main rear wheel 11 is mounted upside down. It can be attached to the flange portion 116 of 11.

As a result, even when the main and rear wheels 11 are turned upside down to change the number of planting rows and the treads of the pair of main and rear wheels 11 are changed, the auxiliary rear wheels 12 can be attached via the extension portion 13. it can.

Further, by integrally configuring the auxiliary rear wheel 12 and the extension portion 13, when the auxiliary rear wheel 12 is removed and transported, the width in the left-right direction can be shortened, and the transportation can be easily performed. .. In addition, it is possible to prevent contact with other objects such as walls and other work vehicles during transportation.

By providing the viewing hole 133b in the second cover 133 of the extension portion 13, the state of the push bolt 15a and the double nut 15b for fixing the main rear wheel 11 to the rear wheel shaft 14 can be easily confirmed.

Further, the extension portion 13 can be attached to the main rear wheel 11 with the viewing hole 133b as a guide, and the extension portion 13 can be easily attached.

Further, by providing the viewing hole 133b, the extension portion 13 can be attached to the main rear wheel 11 without bringing the push bolt 15a or the double nut 15b into contact with the second cover 133. Therefore, the second cover 133 can be made smaller, and an increase in weight can be suppressed.

By providing the thick portion 133d around the viewing hole 133b, the strength of the extension portion 13 can be increased. It is possible to increase the strength by providing ribs around the viewing hole 133b, but in this case, mud tends to accumulate on the ribs. In the present embodiment, the strength can be increased while suppressing the accumulation of mud.

By providing the backup plate 16 on the back surface of the flange portion 116 of the main rear wheel 11, the strength of the flange portion 116 can be increased, and the strength of the main rear wheel 11 can be increased. Therefore, the work can be performed even when the load is large, for example, when working in a deep field. Further, by providing the backup plate 16 on the back surface of the flange portion 116 of the main rear wheel 11, the amount of protrusion in the left-right direction can be suppressed, and it is possible to prevent the assembling property from being lowered while increasing the strength.

By using the three backup plates 16, the backup plate 16 can be made into a general-purpose product that can be used for a plurality of work vehicles, and the cost can be reduced. Further, the backup plate 16 can be arranged between the spokes 122, and the extension portion 13 can be attached to the main rear wheel 11 even when the main rear wheel 11 is turned upside down.

By welding the auxiliary rear wheel mounting portion 130 and the auxiliary shaft 131, for example, the number of parts can be reduced as compared with the case of pin connection, and the cost can be reduced. Further, by reducing the number of parts, it is possible to easily manage the design strength of the parts.

By forming a recess 132a extending in the left-right direction on the first cover 132, the bolt 17a and the nut 17b can be arranged even inside in the radial direction, and the extension portion 13 can be attached to the main rear wheel 11 for attachment. There can be many places. Therefore, the surface pressure of each bolt 17a can be reduced, and the deformation of the flange portion 116 of the main rear wheel 11 and the mounting portion 134 of the extension portion 13 can be suppressed. Further, it is not necessary to increase the diameter of the first cover 132 in order to suppress the deformation, and the strength of the extension portion 13 can be increased while suppressing the increase in weight. Further, the bolt 17a and the nut 17b can be easily attached.

A recess 22d recessed upward is formed in the upper case 22a constituting the front wheel final case 22 accommodating the suspension mechanism 29 of the front wheel 5 and the driven shaft 33. As a result, when the spring 29c of the suspension mechanism 29 contracts, a bag-shaped space is formed by the recess 22d and the washer 33a, and functions as an air cushion. Therefore, when the front wheel 5 rides on the convex portion of the field, it is possible to prevent a sudden push-up from occurring.

Further, by providing the breather 30 communicating with the recess 22d, the responsiveness of the suspension mechanism 29 can be improved. Further, the responsiveness of the suspension mechanism 29 can be adjusted by changing the diameter and length of the breather 30.

[Second Embodiment]
Next, the second embodiment will be described with reference to FIG. FIG. 11 is a cross-sectional view of the rear wheel 10 according to the second embodiment as viewed from above. Here, the parts different from those of the first embodiment will be mainly described, and the same configurations as those of the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

The second cover 133 of the extension portion 13 has a third cover 133e that protrudes radially outward from the second cover 133 and covers the push bolt 15a or the double nut 15b.

As a result, the push bolt 15a and the double nut 15b can be accommodated in the second cover 133 without forming, for example, the visual recognition hole 133b in the second cover 133, and mud can enter the extension portion 13. It can be suppressed. Therefore, deterioration of the push bolt 15a, the double nut 15b, and the like can be suppressed, and sticking can be suppressed.

The third cover 133e may be formed with a visual hole that opens outward in the left-right direction. As a result, the extension portion 13 rotates, the viewing hole is located on the upper side, and even when mud falls from above, it is possible to prevent the mud from entering the extension portion 13, and further, the push bolt. The states of the 15a and the double nut 15b can be visually recognized.

[Third Embodiment]
Next, the third embodiment will be described with reference to FIG. FIG. 12 is a cross-sectional view of the rear wheel 10 according to the third embodiment as viewed from above. Here, the parts different from those of the first embodiment will be mainly described, and the same configurations as those of the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

A discharge hole 133f for discharging mud that has entered the extension portion 13 is formed in the protruding portion 133a of the second cover 133. A plurality of discharge holes 133f may be formed.

Further, a through hole 132b is formed on the tip end side of the first cover 132. The through hole 132b is formed so that the bolt 14c for fixing the fall-prevention washer 14b to the rear wheel shaft 14 and the fall-prevention washer 14b can be visually recognized.

By forming the discharge hole 133f in the protruding portion 133a of the second cover 133, the mud that has entered the extension portion 13 can be discharged to the outside from the discharge hole 133f.

Further, by forming the through hole 132b on the tip end side of the first cover 132, the looseness of the bolt 14c for fixing the fall-prevention washer 14b can be visually recognized.

In addition, only one of the through hole 132b and the discharge hole 133f may be formed.

[Fourth Embodiment]
Next, the fourth embodiment will be described with reference to FIGS. 13 and 14. FIG. 13 is a plan view of the extension portion 13 according to the fourth embodiment. FIG. 14 is a front view of the extension portion 13 according to the fourth embodiment as viewed from the auxiliary rear wheel 12 side. Here, the parts different from those of the first embodiment will be mainly described, and the same configurations as those of the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

The extension portion 13 has an auxiliary rear wheel mounting portion 230 and an auxiliary shaft 231.

The auxiliary rear wheel mounting portion 230 is formed by welding a plurality of sheet metal pieces, and has a mounting portion 232, a rib 233, a first reinforcing plate 234, a second reinforcing plate 235, a cylindrical portion 236, and a shoulder portion 237. And have.

The mounting portion 232 is arranged so as to face the flange portion 116 (see FIG. 7) of the hub 110. Three mounting portions 232 are arranged at intervals of 120 ° along the circumferential direction. The spokes 112 (see FIG. 1) of the main and rear wheels 11 are arranged between the two mounting portions 232. Each mounting portion 232 is formed with three through holes 238 into which bolts 17a (see FIG. 7) are inserted.

The rib 233 is arranged so as to extend along the left-right direction, and is welded to the mounting portion 232 at the inner end portion in the left-right direction. Six ribs 233 are arranged at intervals of 60 ° along the circumferential direction. The rib 233 has two ribs 233 welded to the same mounting portion 232. The rib 233 uses bolts 17a or nuts 17b (see FIG. 7) for the flange portion 116 (see FIG. 7) of the main rear wheel 11 so that the extension portion 13 does not interfere with the through hole 238 of the mounting portion 232. When installing, it is arranged so that the installation work is easy.

Further, the rib 233 is welded to the cylindrical portion 236, the shoulder portion 237, and the auxiliary shaft 131 on the outer side in the left-right direction. Further, it is welded to the first reinforcing plate 234 or the second reinforcing plate 235 arranged between the two ribs 233.

The first reinforcing plate 234 is arranged between the same mounting portion 232 and the two ribs 233 to be welded, and is welded to the ribs 233. Further, the first reinforcing plate 234 is welded to the mounting portion 232 on the inner side in the left-right direction and welded to the cylindrical portion 236 on the outer side in the left-right direction. Inside in the left-right direction, a gap is formed between the first reinforcing plate 234 and the rib 233.

The second reinforcing plate 235 is arranged between the two ribs 233 to be welded to the different mounting portions 232 and is welded to the ribs 233. The second reinforcing plate 235 is arranged at two places. That is, one place where the second reinforcing plate 235 is not arranged is provided between the different mounting portions 232 and the two ribs 233 to be welded. This is a push bolt 15a (see FIG. 7) when the main rear wheel 11 (see FIG. 7) is attached to the rear wheel shaft 14 (see FIG. 7) with the rear wheel shaft mounting portion 115 (see FIG. 7) facing outward in the left-right direction. This is to make the double nut 15b (see FIG. 7) visible.

Further, the second reinforcing plate 235 is welded to the cylindrical portion 236 on the outer side in the left-right direction. A gap for arranging the spokes 112 of the main and rear wheels 11 is formed inside the second reinforcing plate 235 in the left-right direction. Further, a gap is formed between the second reinforcing plate 235, the spokes 112, and the ribs 233.

The cylindrical portion 236 is arranged on the outer side in the left-right direction, and is welded to the shoulder portion 237 at the outer end portion in the left-right direction. The shoulder portion 237 is formed in an annular shape and is welded to the cylindrical portion 236 at the radial outer end and to the auxiliary shaft 131 at the radial inner end.

By forming the auxiliary rear wheel mounting portion 230 of the extension portion 13 by welding sheet metal, the extension portion 13 can be configured without using a mold, and the cost can be reduced.

Further, since gaps are formed between the first reinforcing plate 234 and the rib 233 and between the second reinforcing plate 235, the spokes 112 and the rib 233, the mud discharge property can be improved. .. In addition, it is possible to improve maintainability when mud invades.

[Modification example]
Next, a modified example of the above embodiment will be described.

In the above embodiment, three backup plates 16 are used, but the backup plate 160 may be composed of one member as shown in FIG. FIG. 15 is a schematic view of the backup plate 160 of the modified example.

A notch 161 is formed in the backup plate 160 from the outside toward the center. The notch 161 is formed so as to avoid the through hole 16a, and is formed in a straight line. The width of the notch 161 is larger than the diameter of the rear wheel shaft mounting portion 115 (see FIG. 7).

As a result, the backup plate 160 can be easily attached and the strength can be increased as compared with the case where the three backup plates 16 are used.

As shown in FIG. 16, the notch 161 may be formed by bending. FIG. 16 is a schematic view of the backup plate 160 of the modified example.

When the backup plate 160 is attached to the main rear wheel 11 by bending the notch 161 and fixed with the bolt 17a (see FIG. 7) and the nut 17b (see FIG. 7), the backup plate 160 is attached to the rear wheel shaft 14. (See FIG. 7) or the rear wheel shaft mounting portion 115 (see FIG. 7) can be prevented from falling off, and the backup plate 160 can be easily mounted.

Further, in the above embodiment, the auxiliary rear wheel mounting portion 130 is formed by casting in the extension portion 13, but it may be formed by forging.

As a result, when the auxiliary rear wheel mounting portion 130 and the auxiliary shaft 131 are welded, the steels can be welded to each other, the welding can be easily performed, and the productivity can be improved.

Further, when welding the auxiliary rear wheel mounting portion 130 and the auxiliary shaft 131, a steel pipe such as STKM may be inserted as an intermediate member for welding.

Welding cannot be easily performed between the auxiliary rear wheel mounting portion 130, which is a cast metal, and the auxiliary shaft 131, which is a steel bar, due to a large difference in carbon content. In the modified example, since a steel pipe is inserted as an intermediate member and the auxiliary rear wheel mounting portion 130 and the auxiliary shaft 131 are connected via the steel pipe, welding can be easily performed and the welded portion can be stabilized. Therefore, it becomes easy to maintain the strength balance of the extension portion 13. Further, the welded portion can be made smaller, the extension portion 13, particularly the auxiliary rear wheel mounting portion 130 can be made smaller, the weight can be reduced, and the cost can be reduced.

Further, the auxiliary rear wheel mounting portion 130 and the auxiliary shaft 131 may be integrally molded. In this case, it is desirable to quench the auxiliary shaft 131.

As a result, since the extension portion 13 is configured without welding, the strength design of the extension portion 13 becomes easy. Moreover, since welding is not required, the strength can be increased and the productivity can be improved. Moreover, the number of parts can be reduced.

Further, in the above embodiment, the recess 22d formed in the upper case 22a is communicated with the outside via the breather 30, but the recess 22d may be closed by a plug.

Thereby, for example, when the front wheel 5 rides on the convex portion of the field, it is possible to further suppress the occurrence of a sudden push-up.

Further, the recess 22d formed in the upper case 22a may be communicated with the accumulator.

Thereby, for example, when the front wheel 5 rides on the convex portion of the field, the responsiveness of the suspension mechanism 29 can be improved while further suppressing the occurrence of a sudden push-up.

Further, the recesses 22d formed in the left and right upper cases 22a may be communicated with each other by, for example, one breather 30.

As a result, when the difference between the unevenness of the field between the left and right front wheels 5 is small, the responsiveness of the suspension mechanism 29 can be lowered and the vibration due to the unevenness can be suppressed from being transmitted to the operator. Further, when the difference between the unevenness of the field between the left and right front wheels 5 is large, the responsiveness of the suspension mechanism 29 can be improved.

Further, the assist force of the handle 52 may be increased as the spring 29c of the suspension mechanism 29 contracts.

As a result, it is possible to prevent the difference in unevenness of the field from becoming large and the operation of the handle 52 from becoming heavy.

Further, as shown in FIG. 17, the driver's seat 55 may be rotated forward so that the back surface of the driver's seat 55 becomes horizontal when the tip end side of the driver's seat 55 comes into contact with the steering wheel 52. FIG. 17 is a schematic view showing a state in which the driver's seat 55 is rotated forward.

As a result, the cockpit 55 can be used as a workbench.

Further effects and variations can be easily derived by those skilled in the art. For this reason, the broader aspects of the present invention are not limited to the specific details expressed and described as described above, and the representative embodiments. Thus, various modifications can be made without departing from the spirit or scope of the general concept of the invention as defined by the appended claims and their equivalents.

1 Seedling transplanter (working vehicle)
2 Traveling vehicle body 5 Front wheels 10 Rear wheels 11 Main rear wheels (running wheels)
12 Auxiliary rear wheel (auxiliary wheel)
13 Extension 14 Rear wheel shaft (shaft)
15a Push bolt (fixed part)
15b double nut (fixed part)
16 Backup plate (reinforcing plate)
22 Front wheel final case (case)
22d recess 30 breather (adjustment part)
33 Driven shaft (running transmission shaft)
115 Rear wheel shaft mounting part (mounting part)
116 Flange part 132 1st cover (accommodation part)
133b Visual hole 133d Thick part 133e Third cover 133f Discharge hole 160 Backup plate (reinforcing plate)

Claims (8)

The shaft part that extends in the left-right direction of the traveling vehicle body and transmits the driving force,
A traveling wheel that can be mounted on the shaft portion by inverting the front and back by the mounting portion extending in the left-right direction.
An extension portion that has an accommodating portion capable of accommodating the mounting portion, is attached to the flange portion of the traveling wheel regardless of the mounting direction of the traveling wheel, and extends in the left-right direction.
A work vehicle including an auxiliary wheel attached to the tip of the extension portion. The extension is
The work vehicle according to claim 1, further comprising a cover that covers a fixing portion that fixes the traveling wheel to the shaft portion and projects outward in the radial direction. In the storage part
The work vehicle according to claim 1 or 2, wherein a viewing hole for fixing the traveling wheel to the shaft portion is formed so that the fixing portion can be visually recognized from the outside. The extension is
The work vehicle according to claim 3, further comprising a thick portion that makes the periphery of the viewing hole thicker than other accommodating portions. In the storage part
The work vehicle according to any one of claims 1 to 4, wherein a discharge hole for discharging mud that has entered the inside is formed. The work vehicle according to any one of claims 1 to 5, further comprising a reinforcing plate arranged on the back surface of the flange portion of the traveling wheel regardless of the mounting direction of the traveling wheel. A traveling transmission shaft that extends in the vertical direction of the traveling vehicle body, transmits driving force to the front wheels, and moves up and down together with the front wheels.
A suspension mechanism provided around the traveling transmission shaft and
A case that accommodates the traveling transmission shaft and the suspension mechanism and has an upwardly recessed recess in the upper end inner wall.
The work vehicle according to any one of claims 1 to 6, further comprising an adjusting portion capable of adjusting the internal pressure of the case via the recess. The adjusting part
The work vehicle according to claim 7, wherein the breather communicates with the recess.