Work vehicles

Abstract

To reduce the impossibility of traveling in a constitution with two transmission cases connected.SOLUTION: In a work vehicle (1), a lower part of an upper case (410) is inserted into and installed in an upper part of a lower case (420). A first bearing (423) for receiving a lower end part of the upper case (410) and a second bearing (424) for receiving the upper case (410) on the upper side relative to the first bearing (423) and at an upper end part of the lower case (420) are arranged in the lower case (420). A load of a transmission case (400) in the radial direction is received by the first bearing (423) and the second bearing(424), and a load of the transmission case (400) in the thrust direction is received by either one of the first bearing (423) and the second bearing (424).SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a work vehicle that performs work in farm fields. [Background technology]

[0002] 2. Description of the Related Art With respect to work vehicles such as tractors, rice transplanters, and pesticide spraying vehicles, the technology described in Patent Document 1 below is conventionally known.

[0003] In Patent Document 1 (JP 2019-170332 A), in order to increase the vehicle height, a transmission unit that transmits drive to the wheels is composed of a standard transmission case (410), an extended support transmission case (420), and a final case (430), and the lower end of the standard transmission case (410) is inserted into an upper hole (422) of the extended support transmission case (420). The standard transmission case (410) is supported by two bearings (601, 602) supported by the extended support transmission case (420). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-170332 A ("0042"-"0055", especially "0047") [Patent Document 2] JP 2018-014939 A Summary of the Invention [Problem to be solved by the invention]

[0005] (Problems with the Prior Art) In the configuration shown in Patent Document 1, two bearings (601, 602) of approximately the same diameter are provided at the portion where the upper standard transmission case (410) contacts the inside of the lower extended support transmission case (420), and the two bearings (601, 602) are both configured to support thrust loads and radial loads. However, in this configuration, thrust loads are likely to be applied to both the upper and lower bearings (601, 602), and there is a risk that they will be damaged at the same time if they are subjected to vibrations in the thrust direction as the vehicle travels. If both bearings (601, 602) are damaged at the same time, the vehicle may become unable to travel. If the vehicle becomes unable to travel, it will be necessary to use another work vehicle to move the vehicle out of the field and to move it to a repair site, which will result in a problem of spending a lot of time on the repair work.

[0006] The present invention has a technical object to prevent a vehicle from becoming unable to travel in a configuration in which two transmission cases are connected. [Means for solving the problem]

[0007] In order to solve the above technical problem, the invention described in claim 1 comprises: A traveling vehicle body having wheels; a transmission case that accommodates a transmission body that transmits driving force to the wheels; A work device supported on the traveling vehicle body and performing management work in a farm field; A work vehicle comprising: The transmission case has an upper case and a lower case, The lower part of the upper case is inserted into the upper part of the lower case, a first bearing that receives a lower end of the upper case and a second bearing that receives the upper case at an upper end of the lower case and is disposed above the first bearing; A radial load of the transmission case is supported by the first bearing and the second bearing, and a thrust load of the transmission case is supported by either the first bearing or the second bearing. 、 The transmission body in the transmission case has an upper shaft on an upper side and a lower shaft on a lower side, The upper case is formed with an upper insertion port for the upper shaft, The lower case is formed with a lower insertion port for the lower shaft, The lower case is formed with an axle insertion port into which the axle of the wheel is inserted, A stopper member for preventing the upper case from coming off the lower case is detachable from the axle insertion opening. This is a work vehicle characterized by the above.

[0008] Claim 2 The invention described in A first oil hole through which lubricating oil can be injected is formed on the side of the lower case on which the wheel is mounted, The upper case is formed with a second oil hole through which lubricating oil can be injected, A communicating oil supply hole is formed in a portion of the upper case that is inserted into the lower case, through which the lubricating oil supplied from the second oil supply hole passes to the lower case. Characterized by Claim 1 It is a work vehicle described in.

[0009] Claim 3 The invention described in A mounting rib for a knuckle arm connected to a steering system is formed on the side of the lower case on which the wheels are mounted, The mounting rib is formed with a mounting hole for mounting the grass body. 1. The method according to claim 1, OR 2 It is a work vehicle described in.

[0010] In order to solve the above technical problem, claim 4 The invention described in A traveling vehicle body having wheels; a transmission case that accommodates a transmission body that transmits driving force to the wheels; A work device supported on the traveling vehicle body and performing management work in a farm field; A work vehicle comprising: The transmission case has an upper case and a lower case, The lower part of the upper case is inserted into the upper part of the lower case, a first bearing that receives a lower end of the upper case and a second bearing that receives the upper case at an upper end of the lower case and is disposed above the first bearing; a radial load of the transmission case is supported by the first bearing and the second bearing, and a thrust load of the transmission case is supported by either the first bearing or the second bearing; The working device is It consists of a boom that sprays liquid. R, The boom is mounted so as to be rotatable in the vertical and horizontal directions, and is configured to be movable between a work position where a spraying operation is performed and a storage position where the boom is stored, A boom guard is provided on the traveling vehicle body to receive the boom when the boom is moved to the storage position. The boom guard is a U-shaped plate with a guard plate made of a soft material, and the side plate on the outside of the aircraft is rotatable. 、 The guard plate is biased upward by a biasing member provided on the boom guard, When the boom comes into contact with the guard plate, the side plate rotates so as to rise upward toward the upper part of the aircraft body, When the boom separates from the guard plate, the guard plate is pushed by a biasing member to rotate upward, and the side plate rotates laterally from the raised state. This is a work vehicle characterized by the above. Effect of the Invention

[0011] According to the invention described in claim 1, even if either the first bearing or the second bearing is damaged by a thrust load, the other bearing can continue to drive, and in a configuration in which the two transmission cases are connected, it is possible to prevent the vehicle from becoming unable to drive. Also, claim 1 According to the invention described in 、 The upper shaft is detachable through the upper insertion port, the lower shaft is detachable through the lower insertion port, the axle is detachable through the axle insertion port, and the anti-pullout member is also detachable through the axle insertion port, making maintenance easy. Claim 2 According to the invention described in Claim 1 In addition to the effects described above, the operation of oiling the lower case through the second oil feed hole can be completed in a shorter time than in a case where there is no communicating oil feed hole.

[0012] Claim 3 According to the invention described in claim 1 OR 2 In addition to the effects described above, the attachment and detachment of the grass segments can be performed more easily than in a configuration that does not have mounting ribs. According to the invention described in claim 4, even if either the first bearing or the second bearing is damaged by a thrust load, the other bearing can continue to run, and in a configuration in which the two transmission cases are connected, it is possible to prevent the vehicle from becoming unable to run. Also, claim 4 According to the invention described in 、 The boom guard can be attached to the boom post and the boom hoist to prevent the boom from being damaged. Furthermore, claim 4 According to the invention described in 、In the stored position, the biasing member functions as a suspension to prevent damage to the boom, and the guard plate can be moved in conjunction with the movement of the boom. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a left side view of a chemical solution spraying work vehicle as an example of a work vehicle in an embodiment according to the present invention. [Diagram 2] FIG. 2 is a plan view of the chemical solution spraying vehicle in the embodiment according to the present invention. [Diagram 3] FIG. 3 is a front view of the chemical solution spraying vehicle in the embodiment according to the present invention. [Figure 4] FIG. 4 is a perspective view of a chemical solution spraying vehicle in an embodiment according to the present invention, viewed from diagonally above and to the left and front. [Diagram 5] FIG. 5 is an explanatory view of a main part of the transmission unit according to the embodiment. [Figure 6] FIG. 6 is an explanatory diagram of the state of FIG. 5 with the wheels omitted. [Figure 7] FIG. 7 is an explanatory diagram of the state in which the separating rod is removed from the state shown in FIG. [Figure 8] FIG. 8 is a cross-sectional view of the main part of the transmission unit. [Figure 9] FIG. 9 is an explanatory diagram of the state of FIG. 8 with the wheels omitted. [Figure 10] FIG. 10 is a side view of the transmission unit according to the embodiment. [Figure 11] FIG. 11 is an explanatory diagram of the boom receiver according to the embodiment, in which FIG. 11(A) is an enlarged view of the main part, and FIG. 11(B) is an enlarged view of the main part of the guard plate portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Next, specific examples of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following examples. In the description of the embodiment, the left and right directions in the forward movement direction of the aircraft are referred to as left and right, respectively, and the forward movement direction is referred to as front, and the backward movement direction is referred to as rear. In the following description using the drawings, illustrations of components other than those necessary for the description are omitted as appropriate to facilitate understanding.

[0015] FIG. 1 is a left side view of a chemical solution spraying work vehicle as an example of a work vehicle in an embodiment according to the present invention. FIG. 2 is a plan view of the chemical solution spraying vehicle in the embodiment according to the present invention. FIG. 3 is a front view of the chemical solution spraying vehicle in the embodiment according to the present invention. FIG. 4 is a perspective view of a chemical solution spraying vehicle in an embodiment according to the present invention, viewed from diagonally above and to the left and front.

[0016] 1 to 3 show a state in which left and right spray boom mechanisms (an example of a working device) described later are stored on both the left and right sides of the traveling body (a state in which they are moved to a stored position, a stored posture). Fig. 4 shows a state in which the left spray boom mechanism 100L is stored on the left side of the traveling body, and a state in which the right spray boom mechanism 100R is deployed on the right side of the traveling body (a state in which they are moved to a working position, a spray posture). Further, in FIG. 3, a center spray boom mechanism 100C, which will be described later, is omitted, and in FIG. 4, the center spray boom mechanism 100C and the left side spray boom mechanism 100L are omitted.

[0017] 1 and 2, a chemical spraying work vehicle 1 as an example of a work vehicle of this embodiment has a pair of left and right front wheels 3L, 3R and a pair of left and right rear wheels 4L, 4R. An engine 6 covered by a bonnet 5, a driver's seat 7 located approximately in the center of the main frame, and a steering wheel 8 provided in front of the driver's seat 7 are arranged at the front of the main frame of the running body 2 of the chemical spraying work vehicle 1. A pest control tank 9 for storing chemicals is arranged at the rear of the main frame so as to surround the driver's seat 7 on three sides, the left and right sides and the rear, in a plan view.

[0018] A pest control pump 10 is provided below the pest control tank 9 and on the main frame. A carrier 51 is provided behind the pest control tank 9, and is configured to be able to carry a portable canister 12 made of metal or resin. The portable canister 12 may be a canister containing water, a canister containing fuel, or a canister containing chemicals. In the case of water, water can be poured into the pest control tank 9 at the end of work (when there is no chemical in the pest control tank 9), and the water can be sprayed from the spray nozzle 101 to clean the piping of the pest control spraying device 100. It can also be used to carry spare fuel canisters or chemical canisters.

[0019] A pest control spraying device 100 as an example of a working device is disposed in front of the main frame. The pest control spraying device 100 has a center spray boom mechanism 100C disposed in front of the main frame, and a pair of left and right spray boom mechanisms 100L, 100R rotatably provided at both left and right ends of the front of the main frame. The pair of left and right spray boom mechanisms 100L, 100R are provided with a pair of left and right hydraulic rotating cylinders 110L, 110R that rotate the pair of left and right spray booms 120L, 120R described later via a pair of left and right rotating parts 300L, 300R. The pair of left and right rotating parts 300L, 300R are rotatably attached to both left and right ends of a front horizontal support 220 described later.

[0020] In addition, a lifting link mechanism 200 for lifting and lowering the pest control spraying device 100 is provided on the front side of the main frame. As shown in Figs. 1, 2, and 4, the lifting link mechanism 200 has parallel links 210L, 210R, a front horizontal support 220, and a hydraulic lifting cylinder 230. The parallel links 210L, 210R are supported rotatably on both the left and right sides of the bonnet 5. The front horizontal support 220 is disposed in front of the bonnet 5 and is welded and fixed to the front end of the parallel links 210L, 210R. The hydraulic lifting cylinder 230 lifts and lowers the front horizontal support 220. Since the hydraulic lifting cylinder 230 in the embodiment is composed of a single cylinder, the configuration is simple and the weight is light.

[0021] As shown in Fig. 1, the left parallel link 210L has a left upper link 210La and a left lower link 210Lb. The rear end portions of the left upper link 210La and the left lower link 210Lb are rotatably connected at a predetermined distance by a left link first connecting member 211L. The left link first connecting member 211L has a lower end fixed to the left side of the main frame (left side in the vehicle width direction). The front end portions of the left upper link 210La and the left lower link 210Lb are rotatably connected at a predetermined distance by a left link second connecting member 212L. The right parallel link 210R has the same configuration as the above-mentioned left parallel link 210L.

[0022] The front horizontal support 220 is welded to the lower end of the front side of the left link second connecting member 212L and the lower end of the front side of the right link second connecting member 212R. The left-right width of the front horizontal support 220 is longer than the left-right distance between the left parallel link 210L and the right parallel link 210R, and has a length approximately equal to the wheel distance (tread) between the left and right front wheels 3L, 3R. The left lower link 210Lb and the right lower link 210Rb are connected by a left / right link connecting arm 213 approximately midway between the front end of the bonnet 5 and the front horizontal support pillar 220 in a side view.

[0023] The main body of the hydraulic lift cylinder 230 described above is rotatably attached to the upper end of a cylinder attachment bracket 232 erected in the center of the left-right width of the front horizontal support 220. The tip of a piston rod 231 of the hydraulic lift cylinder 230 is connected to the left-right link connecting arms 213.

[0024] As a result, when the piston rod 231 of the hydraulic lifting cylinder 230 moves in the extension direction, the front ends of the pair of left and right parallel links 210L, 210R rise around the connection points with the left link first connecting member 211L and the right link first connecting member 211R as the pivot axis, and the front horizontal support 220 also rises at the same time.

[0025] In addition, when the piston rod 231 of the hydraulic lifting cylinder 230 moves in the contracting direction, the front ends of the pair of left and right parallel links 210L, 210R descend around the connection points with the left link first connecting member 211L and the right link first connecting member 211R as the pivot axis, and the front horizontal support 220 also descends at the same time.

[0026] According to the above configuration, by operating the left and right spray boom rotation switches (not shown) respectively and operating a pair of left and right hydraulic pivot cylinders 110L, 110R (see Figure 1), the left and right spray booms 120L, 120R can be switched between a spraying work posture (working position) in which they extend out to the left and right of the main frame, and a storage posture (storage position, see Figures 1, 2 and 3) in which they are aligned along both sides of the chemical spraying work vehicle 1. Furthermore, according to the above configuration, the spray height of the chemical solution can be changed by raising and lowering the pest control spraying device 100 using the hydraulic lifting cylinder 230 (see FIG. 1).

[0027] In addition, the chemical solution in the pest control tank 9 is sent to the pest control spraying device 100 side by the pest control pump 10, and the chemical solution is sprayed from a plurality of spray nozzles 101 (see FIG. 2) provided on each of the center spray boom mechanism 100C, the left spray boom mechanism 100L, and the right spray boom mechanism 100R. Specifically, the spray nozzles 101 are provided at predetermined intervals on the left pipe 121L and the right pipe 121R, and the left pipe 121L and the right pipe 121R are fixed along the spray booms 120L and 120R. In the center spray boom mechanism 100C, the spray nozzles 101 are provided at predetermined intervals on the front pipe 121C, and the front pipe 121C is fixed along the front spray boom 120C.

[0028] (Description of the transmission part) In Fig. 3, a left front wheel transmission unit 400L and a right front wheel transmission unit 400R are connected to the left and right ends of the front axle 500F. In Fig. 4, a left rear wheel transmission unit 500L and a right rear wheel transmission unit 500R are connected to the left and right ends of the rear axle 900R. Next, the left front wheel transmission part 400L shown in Figures 1 and 3 will be described. The right front wheel transmission part 400R has a symmetrical configuration to the left front wheel transmission part 400L, so a description thereof will be omitted. Also, the left rear wheel transmission part 500L and the right rear wheel transmission part 500R have the same configuration as the left front wheel transmission part 400L and the right front wheel transmission part 400R, respectively, so a description thereof will be omitted.

[0029] FIG. 5 is an explanatory view of a main part of the transmission unit according to the embodiment. FIG. 6 is an explanatory diagram of the state of FIG. 5 with the wheels omitted. FIG. 7 is an explanatory diagram of the state in which the separating rod is removed from the state shown in FIG. FIG. 8 is a cross-sectional view of the main part of the transmission unit. FIG. 9 is an explanatory diagram of the state of FIG. 8 with the wheels omitted. FIG. 10 is a side view of the transmission unit according to the embodiment.

[0030] 5 to 10, the left front wheel transmission part 400L has an upper case 410 on the upper side, a lower case 420 on the lower side, and a final case 430 disposed corresponding to the left front wheel 3L. 8 and 9, the upper case 410 is formed in a cylindrical shape that inclines outward in the width direction as it goes downward. The inclination angle of the upper case 410 is set so that the front wheels 3L, 3R fit into the furrows of the field and do not interfere with the crops. An upper insertion port 411 is formed at the upper end of the upper case 410. The upper insertion port 411 is closed by an upper cap 412, which is an example of a lid member. A lower end portion 413 of the upper case 410 is inserted into the inside of the lower case 420. The lower end portion 413 has a first bearing portion 413a on the lower side and a second bearing portion 413b on the upper side. In this embodiment, the outer diameter of the second bearing portion 413b is formed to be larger than the outer diameter of the first bearing portion 413a.

[0031] Furthermore, a second oil supply hole 414 into which lubricating oil can be injected is formed in upper case 410 at a position above second bearing portion 413b. Second oil supply hole 414 is configured as a hole penetrating between the outside and the inside of upper case 410, and is normally plugged with a plug (not shown). Furthermore, between first bearing portion 413a and second bearing portion 413b, there is formed a communicating oil supply hole 415. Communicating oil supply hole 415 is formed on the inside of lower case 420 by a hole penetrating between the outside and the inside of upper case 410.

[0032] The communicating oil feed hole 415 allows the lubricating oil injected from the second oil feed hole 414 to pass to the lower case 420 side. In a conventional configuration in which the communicating oil feed hole 415 is not provided, the lubricating oil injected from the second oil feed hole 414 is likely to be blocked and accumulated at the first bearing 423 (described later), and it takes time for the lubricating oil to pass (permeate) through the first bearing 423 and move to the lower case 420 side. In contrast, in the embodiment in which the communicating oil feed hole 415 is provided, the excess lubricating oil injected from the second oil feed hole 414 can be quickly supplied to the lower case 420 side through the communicating oil feed hole 415. Therefore, the work of oiling the lower case 420 through the second oil feed hole 414 can be performed in a short time.

[0033] The lower case 420 has a lower shaft accommodating portion 421 disposed on an extension of the axial direction (thrust direction) of the upper case 410, and a knuckle portion (axle support portion) 426 formed on the outer side (left side) in the width direction of the lower shaft accommodating portion 421. The lower shaft accommodating portion 421 is formed in a cylindrical shape extending on an extension of the thrust direction of the upper case 410. A lower insertion port 421a is formed at the lower end of the lower shaft accommodating portion 421. The lower insertion port 421a is closed by a lower cap 422 as an example of a lid member.

[0034] A lower first bearing 423 and an upper second bearing 424 are supported on the upper part of the lower shaft accommodating part 421. The first bearing 423 supports the first bearing part 413a of the upper case 410, and the second bearing 424 supports the second bearing part 413b. Therefore, the lower case 420 is rotatably supported by the two bearings 423 and 424 with respect to the upper case 410. In the embodiment, the first bearing 423 and the second bearing 424 are larger than the first bearing 423 in accordance with the difference in outer diameter between the first bearing part 413a and the second bearing part 413b.

[0035] In the embodiment, the contact surface 416 of the upper case 410 is supported in a state of contact and abutment against the upper surface of the lower first bearing 423. Therefore, the first bearing 423 receives not only the load in the radial direction (circumferential direction, rotational direction) of the upper case 410 but also the load in the thrust direction (axial direction). On the other hand, in the embodiment, the upper second bearing 424 has a predetermined gap (play) between the upper surface and the upper case 410. Therefore, the second bearing 424 is set to receive only the load in the radial direction (circumferential direction, rotational direction) of the upper case 410 and not to receive the load in the thrust direction (axial direction). The configuration is not limited to the example shown in the embodiment, and it is also possible to set the second bearing 424 to receive the load in the thrust direction and the first bearing 423 not to receive the load in the thrust direction.

[0036] In the embodiment, a retaining ring 417 as an example of a retaining member is attached to the lower end of upper case 410 at a position below first bearing 423. Retaining ring 417 is formed in a ring shape with a diameter larger than the inner diameter of first bearing 423. Therefore, when retaining ring 417 is attached, the downward movement of upper case 410 in the thrust direction is restricted by the top surface of first bearing 423, and the upward movement of upper case 410 in the thrust direction is restricted by retaining ring 417. Therefore, by attaching retaining ring 417, upper case 410 is prevented from coming off lower case 420.

[0037] 8 to 10, the knuckle portion 426 has a gear accommodating space 426a formed as a ring-shaped recess on the left side surface. A bearing support hole (axle insertion hole) 426b is formed in the center of the gear accommodating space 426a on the extension of the axle 427 of the left front wheel 3L. The bearing support hole 426b penetrates from the outside (left side) of the knuckle portion 426 to the lower shaft accommodating portion 421 side. An axle bearing 428 is supported in the bearing support hole 426b, and the axle bearing 428 rotatably supports the axle 427. When the axle bearing 428 is removed, the lower end of the upper case 410 is accessible through the bearing support hole 426b. Therefore, the retaining ring 417 is configured to be detachable through the bearing support hole 426b.

[0038] Also, a gear passage opening 426c penetrating from the outside of the knuckle portion 426 to the inside of the lower shaft accommodating portion 421 is formed in the lower portion of the gear accommodating space 426a. A first oil supply hole 426d is formed above the bearing support hole 426b, penetrating from the outside of the knuckle portion 426 to the inside of the lower shaft accommodating portion 421. Lubricating oil can be directly injected into the inside of the lower shaft accommodating portion 421 through the first oil supply hole 426d.

[0039] Additionally, an air vent hole 426e is formed above first oil feed hole 426d, penetrating the outside of knuckle portion 426 and the inside of gear accommodating space 426a. Therefore, even if the air pressure (internal pressure) in lower case 420 increases due to a rise in temperature during operation, a rise in the temperature of the lubricating oil, changes in outside air temperature, etc., the internal pressure can be prevented from becoming too high through air vent hole 426e. An upwardly extending knuckle arm attachment rib 429 is formed on the upper portion of the knuckle portion 426. In Fig. 7, an attachment hole 429a as an example of an attachment portion for a grass segment is formed in the vertical center of the knuckle arm attachment rib 429.

[0040] A final case 430 is supported on the left side of the knuckle portion 426. A hub bearing 431 is supported on the final case 430 in correspondence with the axle bearing 428. The hub bearing 431 rotatably supports a wheel hub 432 connected to the axle 427. A disk portion of the left front wheel 3L is detachably fastened to the wheel hub 432 with bolts.

[0041] (Description of transmission components) 8 and 9, inside the front axle 500L, a first transmission shaft 440, to which the driving force from the engine is transmitted, is rotatably supported by a first shaft bearing 441. The first shaft bearing 441 is supported by the upper case 410. A first bevel gear 442 is supported on the outer end of the first transmission shaft 440.

[0042] An upper shaft 443 is disposed inside the upper case 410. An upper end of the upper shaft 443 is rotatably supported by a second shaft bearing 444. The second shaft bearing 444 is supported by the upper case 410. A second bevel gear 446 is supported at the upper end of the upper shaft 443. The second bevel gear 446 meshes with the first bevel gear 442. The length of the upper shaft 443 in the embodiment is formed shorter than the length of the upper case 410, and the lower end of the upper shaft 443 has a length corresponding to the vicinity of the position of the second bearing portion 413b. The upper shaft 443 is detachable through an upper insertion port 411 of the upper case 410, making it easy to attach and detach the upper shaft 443 during maintenance.

[0043] A lower shaft 447 is disposed inside the lower shaft accommodating portion 421 of the lower case 420. The lower end of the lower shaft 447 is rotatably supported by a third shaft bearing 448. The third shaft bearing 448 is supported by the lower case 420. A third bevel gear 449 is supported on the lower end of the lower shaft 447 at a position above the third shaft bearing 448. The lower shaft 447 is detachable through a lower insertion port 421a of the lower case 420, making it easy to attach and detach the lower shaft 447 during maintenance.

[0044] A coupling 451, which is an example of a connecting member, is attached between the upper end of the lower shaft 447 and the lower end of the upper shaft 443. The coupling 451 is configured as a cylindrical member. The lower end of the upper shaft 443 is inserted into the upper end of the coupling 451, and the upper end of the lower shaft 447 is inserted into the lower end of the coupling 451. Therefore, the upper shaft 443 and the lower shaft 447 are connected by the coupling 451 and can rotate together. Note that a gap is formed between the coupling 451 and the inner circumferential surface of the upper case 410, through which lubricating oil can sufficiently pass. In addition, when replacing the coupling 451 for maintenance, it can be attached and detached together with either the upper shaft 443 or the lower shaft 447, or it can be attached and detached through the bearing support hole 426b with the lower shaft 447 partially removed.

[0045] A fourth bevel gear 452 is accommodated in the gear accommodating space 426a of the knuckle portion 426. The fourth bevel gear 452 is fixedly supported by the axle 427. The fourth bevel gear 452 passes through the gear passing opening 426c and meshes with the third bevel gear 449.

[0046] Therefore, when drive is transmitted to the first transmission shaft 440, rotation is transmitted through the first bevel gear 442, the second bevel gear 446, the upper shaft 443, the coupling 451, the lower shaft 447, the third bevel gear 449, the fourth bevel gear 452, the axle 427, and the wheel hub 432, causing the left front wheel 3L attached to the wheel hub 432 to rotate. The first transmission shaft 440, the upper shaft 443, and the lower shaft 447 constitute transmission bodies 440, 443, and 447 of the embodiment.

[0047] (Explanation of steering system) 5 to 7 and 10, knuckle arm 460 is supported on knuckle arm mounting rib 429 of lower case 420. Knuckle arm mounting rib 429 and knuckle arm 460 are fastened together with a bolt, and to facilitate the tightening of the bolt, it is desirable to give the exterior of chemical solution spraying vehicle 1 a narrowed shape so that a tool for the tightening work can be easily inserted. An arm portion 461 is formed at the upper end of the knuckle arm 460, and a steering system (not shown) is connected to the tip of the arm portion 461. Therefore, as steering handle 8 is operated, the operation is transmitted to knuckle arm 460 via the steering system, and lower case 420 is rotated relative to upper case 410 by bearings 423, 424. As lower case 420 rotates, the direction of front wheels 3R, 3L changes, and the traveling direction of chemical spraying vehicle 1 changes to the direction operated by steering handle 8.

[0048] (Explanation of the splitting rod) 5 and 6, a grass dividing rod 470, which is an example of a grass dividing body, is supported in the mounting hole 429a of the knuckle arm mounting rib 429. The grass dividing rod 470 is a member formed by bending a rod-shaped member so as to surround the front side of the wheels 3L, 3R, and is a member for pushing aside vegetable leaves in the field so that the leaves are not caught in the rotation of the wheels 3L, 3R when the chemical spraying work vehicle 1 is traveling. In the embodiment, one end of the grass dividing rod 470 is formed into a flange shape, and the flange-shaped portion is screwed into the mounting hole 429a. In the conventional configuration, the dividing rod was also fastened to the bolt that attached the knuckle arm mounting rib 429 and the knuckle arm 460, but when trying to attach or detach only the dividing rod, it was necessary to also remove the knuckle arm 460, which was a cumbersome task. In contrast, in the embodiment, the dividing rod 470 can be attached and detached to the mounting hole portion 429a of the knuckle arm mounting rib 429, making the attachment and detachment work easy.

[0049] (Explanation of the boom support) FIG. 11 is an explanatory diagram of the boom receiver according to the embodiment, in which FIG. 11(A) is an enlarged view of the main part, and FIG. 11(B) is an enlarged view of the main part of the guard plate portion. 1 to 4, a boom receiver 480 is disposed behind the pest control tank 9. The boom receiver 480 extends upward from the rear of the pest control tank 9 and then has a boom frame portion 481 extending to both the left and right sides, and boom guards 482 disposed at both the left and right tip portions of the boom frame portion 481. The boom guards 482 support the lower surfaces of the spray booms (boom sprayers) 120L, 120R to receive the spray booms 120L, 120R. In FIG. 11(A), the boom guard 482 has a guard fixing part 483 and a guard movable part 484. The guard fixing part 483 is disposed on the inside in the width direction of the spraying booms 120L, 120R. The rear part of the lower end of the guard fixing part 483 is fixed to the boom frame part 481 by welding or the like. The guard fixing part 483 has a fixed guide 483a formed at the upper end. The fixed guide 483a is formed to be inclined in a direction away from the spraying booms 120L, 120R.

[0050] The guard movable part 484 has a plate-shaped bottom plate part 484a and a side plate 484b extending upward from the outer end of the bottom plate part 484a in the width direction. Therefore, the guard movable part 484 is formed in a substantially L-shape. The guard movable part 484 is supported rotatably with respect to the boom frame part 481 around a rotation shaft 484c disposed between the bottom plate part 484a and the side plate 484b. The guard movable part 484 in the embodiment is configured to be movable between a stored position indicated by a solid line in FIG. 11 and a rotation position indicated by a dashed line in FIG. 11.

[0051] A rubber guard plate 485, which is an example of an elastic material, is supported on the upper surface of the bottom plate portion 484a and the inner surface of the side plate 484b. In FIG. 11(B), the guard plate 485 is fixed to the bottom plate portion 484a and the side plate 484b with a screw 485a. The guard plate 485 has a recess 485b corresponding to the shape of the screw head so that the screw head of the screw 485a does not protrude above the upper surface of the guard plate 485. Therefore, when the spray boom 120L, 120R contacts the bottom plate portion 484a or the side plate 484b, damage to the spray boom 120L, 120R due to contact between the screw 485a and the spray boom 120L, 120R is suppressed. In the conventional configuration, damage can be suppressed by slowing down the moving speed of the spray boom 120L, 120R, but there is a problem that it takes time to unfold and store the spray boom, and this problem can be solved in the embodiment.

[0052] A spring stay 486 as an example of a biasing support portion is disposed below the bottom plate portion 484a. The rear end of the spring stay 486 is fixed to the boom frame portion 481 by welding or the like. A spring 487 as an example of a biasing member is disposed between the spring stay 486 and the bottom plate portion 484a. The spring 487 applies a force in a direction to bounce the bottom plate portion 484a upward, that is, in a direction to move the bottom plate portion 484a toward the rotation position. The biasing member is not limited to the spring 487, and may be made of rubber or the like.

[0053] Therefore, in the boom receiver 480 of the embodiment, when the spray booms 120L, 120R are moved to the storage position, the spray booms 120L, 120R are placed on the upper surface of the bottom plate portion 484a and stored between the side plate 484b and the guard fixing portion 483. Therefore, in this state, the guard fixing portion 483, the bottom plate portion 484a, and the side plate 484b are substantially U-shaped when viewed from the front. Note that, when the spray booms 120L, 120R are received on the bottom plate portion 484a, the spring 487 is compressed by the weight of the spray booms 120L, 120R. Therefore, in the storage position, the spring 487 also functions as a suspension (buffer).

[0054] When the spray booms 120L, 120R move from the storage position to the working position, in the embodiment, the spray booms 120L, 120R move outward in the left-right direction. At this time, the side plate 484b is pressed by the spray booms 120L, 120R, and the guard movable part 484 moves toward the rotation position by the elastic force of the spring 487, so that the spray booms 120L, 120R can move outward. In addition, when the spray booms 120L, 120R move from the working position to the storage position, as the spray booms 120L, 120R move inward in the left-right direction, the spray booms 120L, 120R push the upright bottom plate portion 484a, causing the bottom plate portion 484a to collapse as it moves toward the storage position.

[0055] In the conventional configuration, since the guard movable part 484 is not provided, the spray booms 120L, 120R are once moved upward to a position higher than the upper end of the side plate, and then moved outward to avoid the side plate. In other words, a process of lifting and a process of deploying outward were required. When storing, a process of moving inward and then lowering was required. In addition, the spray boom is a long member and is prone to bending and swaying, so it was necessary to leave a sufficient margin for the lifting and lowering distance. If the lifting distance was insufficient, there was a risk that the spray boom would come into contact with the side plate and be damaged. In contrast, in an embodiment having a guard movable part 484, the raising and lowering processes are not required, and the deployment and storage operations of the spraying booms 120L, 120R can be completed in a short time, and even if the spraying booms 120L, 120R come into contact with the bottom plate part 484a or the side plate 484b, they can rotate to mitigate the impact and suppress damage.

[0056] (Operation of the embodiment) In the embodiment of the chemical spraying vehicle 1 having the above-mentioned configuration, at the connecting portion between the upper case 410 and the lower case 420, the first bearing 423 of the two bearings 423, 424 receives a load in the thrust direction, but the second bearing 424 does not receive a load in the thrust direction. Therefore, when a load in the thrust direction acts on the upper case 410 and the lower case 420 due to the vertical movement of the chemical spraying vehicle 1 while traveling or working, the second bearing 424 is almost never damaged if the first bearing 423 is not damaged. Even if the first bearing 423 is damaged, the second bearing 424 can receive the load in the thrust direction. Therefore, even if the first bearing 423 is damaged, the second bearing 424 can continue traveling, and the inability to travel is suppressed. Therefore, the chemical spraying vehicle 1 can be moved out of the field or to a repair site. [Explanation of symbols]

[0057] 1...Work vehicle, 2...Traveling vehicle, 3L,3R…wheels, 100...Working device, 120L, 120R…Boom, 400…Transmission case, 410…Upper case, 411…Upper socket, 414...Second lubrication hole, 415...Communicating lubrication hole, 417...Preventive member, 420…Lower case, 421a…Lower inlet, 423…First bearing, 424…2nd bearing, 426b...Axle insertion port, 426d...1st oil hole, 427...Axle, 429…Mounting rib, 429a...Mounting hole portion, 440, 443, 447...Transmission shaft, 443…Upper shaft, 447…Lower shaft, 460…Knuckle arm, 470...Branch body, 482…Boom guard, 485…guard plate, 487...biasing member.

Claims

1. A traveling vehicle body having wheels; a transmission case that accommodates a transmission body that transmits driving force to the wheels; A work device supported on the traveling vehicle body and performing management work in a farm field; A work vehicle comprising: The transmission case has an upper case and a lower case, The lower part of the upper case is inserted into the upper part of the lower case, a first bearing that receives a lower end of the upper case and a second bearing that receives the upper case at an upper end of the lower case and is located above the first bearing, a radial load of the transmission case is supported by the first bearing and the second bearing, and a thrust load of the transmission case is supported by either the first bearing or the second bearing; The transmission body in the transmission case has an upper shaft on an upper side and a lower shaft on a lower side, The upper case is formed with an upper insertion port for the upper shaft, The lower case is formed with a lower insertion port for the lower shaft, The lower case is formed with an axle insertion port into which the axle of the wheel is inserted, A stopper member for preventing the upper case from coming off the lower case is detachable from the axle insertion opening. A work vehicle characterized by:

2. A first oil hole through which lubricating oil can be injected is formed on the side of the lower case on which the wheel is mounted, A second oil hole through which lubricating oil can be injected is formed in the upper case, A communicating oil supply hole is formed in a portion of the upper case that is inserted into the lower case, through which the lubricating oil supplied from the second oil supply hole passes to the lower case.

2. The work vehicle according to claim 1 .

3. A mounting rib for a knuckle arm connected to a steering system is formed on the side of the lower case on which the wheels are mounted, The mounting rib is formed with a mounting hole for mounting the grass body.

3. A work vehicle according to claim 1 or 2.

4. A traveling vehicle body having wheels; a transmission case that accommodates a transmission body that transmits driving force to the wheels; A work device supported on the traveling vehicle body and performing management work in a farm field; A work vehicle comprising: The transmission case has an upper case and a lower case, The lower part of the upper case is inserted into the upper part of the lower case, a first bearing that receives a lower end of the upper case and a second bearing that receives the upper case at an upper end of the lower case and is located above the first bearing, a radial load of the transmission case is supported by the first bearing and the second bearing, and a thrust load of the transmission case is supported by either the first bearing or the second bearing; The working device comprises a boom for spraying liquid, The boom is mounted so as to be rotatable in the vertical and horizontal directions, and is configured to be movable between a work position where a spraying operation is performed and a storage position where the boom is stored, A boom guard is provided on the traveling vehicle body to receive the boom when the boom is moved to the storage position. The boom guard has a U-shaped plate and a guard plate made of a soft material, and the side plate on the outer side of the aircraft is rotatable. The guard plate is biased upward by a biasing member provided on the boom guard, When the boom comes into contact with the guard plate, the side plate rotates so as to rise upward toward the upper part of the aircraft body, When the boom separates from the guard plate, the guard plate is pushed by a biasing member to rotate upward, and the side plate rotates laterally from the raised state. A work vehicle characterized by:

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