JP5476151B2 - Riding machine - Google Patents

Description

  The present invention relates to a riding type farm working machine such as a riding type rice transplanter, and particularly has a feature in a support structure of a chassis (frame for supporting various members and devices).

  There is a riding type rice transplanter as an example of a riding type farm working machine. The riding-type rice transplanter has a traveling machine body supported by front wheels and rear wheels, and a seedling planting device is disposed behind the traveling machine body so that the height can be adjusted. The traveling machine body is provided with a seat and a steering handle and is equipped with an engine, and traveling and seedling work are performed by power from the engine. The power of the engine is transmitted to a mission (transmission device) having a mission case, and the rotation is appropriately adjusted by the mission.

  Passenger-type rice transplanters generally have a four-wheel drive system in which the front and rear wheels are driven. For this reason, a front axle for driving the front wheels and a rear axle for driving the rear wheels are provided. Power is transmitted from the mission to the axle.

  Looking at the framework of the traveling machine body, there is a type in which an engine, a transmission case, etc. are mounted on a chassis made of a frame material. For example, as in Patent Document 1, a transmission case and a rear axle case are connected by a connecting body. There is also a type in which the transmission case and the rear axle case are used as the structural material (strength member) of the traveling aircraft. In Patent Document 1, the rear end portion of the chassis is supported by a rear axle case via a rear column.

  In a riding type rice transplanter, in general, a seedling planting device is connected to a traveling machine body through a link device composed of a top link and a lower link so as to be movable up and down. The left and right horizontally long parts are connected via brackets, and the lower link is connected to the left and right horizontally long shafts mounted on the left and right rear columns.

  The mission case and the rear axle case have a sturdy structure because of the function of supporting the gears in a freely rotatable manner. Therefore, when configured as in Patent Document 1, the mission case and the rear axle case are driven. Since it can also be used as the structural material of the fuselage, there is an advantage that the chassis made of the frame material can be simplified.

Japanese Patent No. 3804926

  Now, in connecting the link device that supports the seedling planting device so that it can be raised and lowered, adopting a configuration in which both the top link and the lower link are connected to the rear strut has the advantage of simplifying the connection structure, If the interval between the columns is too wide, the shaft for supporting the link must be lengthened, and the connection structure becomes large, and the bending strength of the shaft for connecting the link decreases.

  In recent years, rice transplanters have been increased in size to improve work efficiency. However, as the size of the traveling aircraft increases, the rear axle case also becomes larger. Then, as shown in Patent Document 1, if the rear column is supported by the rear axle case, Since the spacing between the support columns is also greatly increased, it can be said that when the rice transplanter is increased in size, problems such as an increase in the connection structure when the link is connected to the rear support column will become more prominent.

  On the other hand, it is normal that there are irregularities on the field and on the road, and for this reason, the grounding resistance of each wheel is usually unbalanced even when seedling planting work or running on the road. As an extreme unbalanced state, a state in which one wheel floats and travels on three wheels can be mentioned. When an imbalance occurs in the ground resistance of each wheel in this way, an external force that twists around the axial center extending in the front-rear direction acts on the traveling machine body due to its own weight, and a load is also imposed on the rear axle case.

  As described above, in recent years, rice transplanters have been increasing in size, but since the weight increases as the size increases, the torsional force acting on the traveling machine body when traveling in an unbalanced state increases, and the rear axle case is applied. It can be said that the burden becomes larger.

  The present invention has been made in view of such a current situation, and an object of the present invention is to provide a riding type agricultural working machine that is particularly excellent in adaptability to an increase in the size of a traveling machine body.

According to the first aspect of the present invention, a rear axle case for transmitting power from a driving source to a rear wheel is disposed below a rear portion of a chassis composed of a plurality of frame members, and the rear portion of the chassis is a rear column. In the riding type agricultural machine having a traveling machine body that is supported by the rear axle case via the rear axle case, the rear axle case has a base portion and left and right rearward projecting portions, and is substantially U-shaped in plan view. The rear wheels are supported by the left and right rearward projecting parts, and left and right lateral stays are spanned and fixed to the rearward projecting parts. Are fastened to the left and right rearward projecting portions with bolts from above, and the rear support is supported by the stay.

  According to a second aspect of the present invention, in the first aspect, a transmission case having a built-in traveling speed change mechanism and a left and right front axle is disposed in front of the rear axle case, and the front axle has a front wheel. The transmission case and the rear axle case are connected by a connecting body, and the transmission case and the rear axle case function as a structure of the traveling machine body. According to a third aspect of the present invention, in the first or second aspect, the stay is fixed to the upper surface of the left and right rearward projecting portion with a bolt.

  The invention of claim 4 is any one of claims 1 to 3, wherein the rear axle case is constituted by a U-shaped main case in a plan view and a side case that overlaps with this from the left and right outer sides. For this reason, the left and right side cases respectively constitute a part of the base part and a part of the rearward projecting part, and the stay is fixed to the side case.

  In the present invention, since the rear column is supported by the stay, the position of the rear column can be set regardless of the size of the rear axle case. Therefore, for example, when two rear struts are arranged on the left and right and a working device such as a seedling planting device is connected to this by a link, the left and right rear struts can be arranged at optimal positions according to the size of the link, etc. As a result, the link connection structure can be simplified to contribute to weight reduction and the like. In addition, since the left and right rearward projecting portions of the rear axle case are connected by stays, the rear axle case has a robust structure as a whole, and the support strength of the rear wheel is significantly improved.

  According to the invention of claim 2, since the transmission case and the rear axle case can be used as the structural material (strength member) of the traveling machine body, it is possible to contribute to the simplification of the structure of the entire traveling machine body as in Patent Document 1.

  If the stay is fixed to the upper surface of the rearward projecting portion of the rear axle case as in claim 3, the height of the stay becomes higher than that of the case where the stay is fixed to the inner surface of the rearward projecting portion. As a result, the bending strength of the rear column can be improved. Moreover, since the upper surface of the rear axle case is in an open state, the fastening operation can be easily performed when the stay is fastened with the bolt. (If the stay is fixed to the inner surface of the rearward projecting portion, it may be difficult to rotate the bolt. .)

  Also, if the stay is fixed to the inner surface of the rearward overhanging part with left and right horizontally long bolts, if there is an error in the rear axle case machining dimension or the stay machining dimension, the left and right rearward overhanging parts will be pushed out by the stay or conversely There is a possibility that the rear axle case is stressed due to a phenomenon of being pulled or the like, which may cause a decrease in strength. However, when the stay is fixed to the upper surface of the rearwardly projecting portion as in claim 3, the rear axle is fixed. Since the processing error of the case and the processing error of the stay can be absorbed by the clearance between the bolt and the bolt hole, no stress is generated in the rear axle case and the strength reduction can be prevented. This is also the advantage of claim 3.

  Now, since the rear axle case has a hollow structure, it needs to be constituted by a plurality of members. In addition, various configurations can be considered for the structure formed by a plurality of members to form a hollow structure. When the main case is configured by a U-shaped main case in plan view and a side case that overlaps from the left and right outer sides as in claim 4, the main case As a result, a rough form of the rear axle case is formed, which has an advantage of excellent strength. Further, since the rear axle is horizontally long, the gear shaft to which the gear group is attached is also horizontally long. Therefore, the gear can be easily attached by providing the bearing of the gear shaft in the main case and the side case. Also in this aspect, it is reasonable to configure the rear axle case with a main case and a side case.

  If the rear axle case is composed of the main case and the side case as in claim 4, the side case is provided with a bearing for supporting the rear wheel, and thus a large load acts on the side case. In claim 4, since the left and right side cases, which are subjected to a large load, are connected by stays, the robustness of the rear axle case as a whole has been greatly improved. The strength against torsion can be improved.

It is a whole side view of a rice transplanter in the state where a body cover was removed. (A) is an overall plan view of a rice transplanter with a vehicle body cover attached, and (B) is a partially broken side view of only a traveling machine body. It is a separated perspective view of a traveling machine body. It is a rough top view of a traveling body. It is a partially broken side view of a traveling machine body. It is a perspective view which shows a chassis and a lower structure. (A) is a perspective view showing a connected state between the lower connector and the transmission case, (B) is a perspective view showing a connected state between the lower connector and the rear axle case, (C) a lower connector and a reinforcing frame body. FIG. It is a top view in the state where the fuel tank was shifted to the side. It is a partial side view of a lower structure. It is a back perspective view of an important section. It is a separate perspective view of the principal part. It is a partially broken side view which shows the connection structure of a link apparatus. It is an isolation | separation perspective view which shows the connection structure of a link apparatus. It is a figure which shows a modification, (A) is an isolation | separation perspective view, (B) is an isolation | separation side view, (C) is sectional drawing seen from CC view direction of (B) in the assembled state.

  Hereinafter, an embodiment in which the present invention is applied to a riding type rice transplanter (hereinafter simply referred to as “rice transplanter”) will be described with reference to the drawings. In the following description, the terms “front and rear” and “left and right” are used to specify the direction. These terms are based on the direction of the driver sitting in the forward direction unless otherwise specified. Is displayed.

(1). Outline of rice transplanter First, the outline of rice transplanter will be explained. As can be easily understood from FIGS. 1 and 2, the rice transplanter has a traveling machine body 1 and a seedling planting device 2 as basic elements, and the seedling planting device 2 is connected to the rear part of the traveling machine body 1 via a link mechanism 3. It is connected to move up and down. The seedling planting device 2 has a vertical feeding mechanism, a lateral feeding mechanism, and a planting unit for the seedling mat. In addition, the rice transplanter of this embodiment is an 8-row planting type.

  The traveling machine body 1 includes left and right front wheels 4 and a rear wheel 5, and the front wheels 4 and the rear wheels 5 are driven by power (the rear wheel 5 is provided with an auxiliary wheel to be a double system or a triple system. Sometimes.). The traveling machine body 1 has a seat 6 on which a driver sits and a steering handle 7 disposed in front of the seat 6. The seat 6 and the steering handle 7 are disposed at the left and right intermediate portions of the traveling machine body 1. Although only shown in FIG. 2, a preliminary seedling stand 8 is arranged in front of the seat 6 and on the left and right sides.

  For example, as can be understood from FIGS. 4 and 6, the traveling machine body 1 includes left and right front side frames 9 and a rear side frame 10 that extend in the front-rear direction. The left and right rear side frames 10 are narrower than the front side frame 9, and the front and rear side frames 9 and 10 are connected via a left and right laterally long midframe 11. The left and right front side frames 9 are connected by a front frame 12 at their front end portions.

  The rear side frame 10 is inclined rearward in a side view so as to increase in height as it goes rearward, and left and right laterally long rear frames 13 are connected to the rear ends of the left and right rear side frames 10. The left and right rear columns 14 that support the rear frame 13 are fixed to the rear frame 13. The rear column 14 is disposed inside the rear side frame 10. Of each frame, the mid frame 11 and the rear frame 13 use round pipes, and the other frames use square pipes.

  By connecting the front side frame 9 and the rear side frame 10 with the mid frame 11, the size (thickness), position, and posture of the front side frame 9 and the rear side frame 10 can be easily changed. .

  As shown in FIG. 3, a rear lateral stay 17 is disposed slightly in front of the rear frame 13, and the rear lateral stay 17 is attached to an upward opening U-shaped hanger bracket 18 welded to the rear side frame 10. It is fixed. A gate-type frame 19 having a downward opening is fixed to the front end portions of the left and right rear side frames 10, and the front end portion of the seat support unit 20 is fixed to the gate-type frame 19 as shown in FIG. The rear part of the seat support unit 20 is fixed to a stay (not shown). The seat 6 is connected to the seat support unit 20 so that the seat 6 can be tilted forward with its front end as the center.

  As shown in FIGS. 3 and 4, a plurality of outward branch frames 15 projecting outward in the left and right directions are fixed to the front side frame 9, and the stand seedling stand 8 (see FIG. 2) is secured by the branch frame 15. I support it. A longitudinal auxiliary frame 21 is disposed outside the side frames 9, 10. The auxiliary frame 21 is fixed to the branch frame 15, the rear lateral stay 17, the rear frame 13, and the like.

  In the present embodiment, the front and rear side frames 9 and 10, the mid frame 11, the front frame 12 and the rear frame 13 constitute the main part of the chassis (frame structure) 22 (see FIGS. 3, 4 and 6). As shown in FIG. 2, a portion of the traveling machine body 1 on which a person is placed is covered with a vehicle body cover 23, which includes a front side frame 9, a branch frame 15, an auxiliary frame 21, a rear horizontal stay 17, a rear It is supported by a frame 13 or the like.

  A control floor on which a seated operator places his / her foot is composed of a vehicle body cover 23, which is indicated by reference numeral 23a in FIG. As shown in FIG. 2A, the vehicle body cover 23 also includes shoulder portions 23b that extend to the left and right sides and the rear of the seat 6. Although not shown, a fertilizer application device may be disposed on the shoulder 23b. The body cover 23 is composed of a plurality of parts. A mat is often disposed on the control floor 23a.

  The steering handle 7 is attached to a handle shaft built in the handle post 24. For example, as shown in FIG. 3, in the present embodiment, the engine 25 as a drive source is disposed in the front part of the traveling machine body 1 (in front of the control floor 23 a), and the engine 25 is supported by the engine support 26. Yes.

  The engine support 26 includes a front support frame 26a having a U-shape or U-shape that opens upward, a rear support frame 26b, and a lower support frame 26c that connects the front and rear support frames 26a and 26b. The front and rear support frames 26 a and 26 b are fixed to the front side frame 9. The engine 25 is attached to the engine support 26 via engine brackets 27 and 28 and vibration-proof rubber 29.

  The engine 25 is disposed in a state where it is sunk below the front side frame 9. The engine 25 is disposed so that the crankshaft is horizontally long and the output pulley is disposed on the left side of the crankcase. The engine 25 of this embodiment is a water-cooled diesel engine.

  Behind the engine 25, a mission case 31 incorporating a gear group is arranged. An HST (hydrostatic continuously variable transmission) 32 as an example of a continuously variable transmission is attached to the left side surface of the transmission case 31, and the power of the engine 25 is primarily transmitted to the HST 32 by a belt. It is transmitted to the gear group. In addition to the gear group, the transmission case 31 incorporates a clutch, a brake, etc., but the description is omitted because it is not directly related to the present invention.

  For example, as shown in FIG. 6, a front axle device 33 is attached to the left and right side surfaces of the mission case 31, and the front wheel 4 is attached to the front axle device 33. The front axle device 33 includes an upper case 33a fixed to the transmission case 31, and an axle case 33b attached to the upper case 33a via a buffer mechanism so as to be movable up and down. The upper case 33a is also fixed to the front side frame 9.

  The rear wheel 5 is attached to the rear axle case 34. The rear axle case 34 has a left and right longitudinal base portion 34a and left and right rearward protruding portions 34b protruding rearward from the base portion 34a, and has a U-shape in plan view as a whole. A rear axle 34c protrudes leftward and rightward from the rearward projecting portion 34b, and the rear wheel 5 is fixed to the rear axle. Further, left and right horizontally long stays 35 are inserted and fixed to the left and right rearwardly projecting portions 34 b, and the rear column 14 is fixed to the stays 35.

  As can be understood from FIG. 3, the rear end of the transmission case 31 and the front end of the rear axle case 34 are connected by a hollow circular lower connecting body 36, and the lower connecting body 36 and the midframe 11 are U-viewed. They are connected by a reinforcing frame body (reinforcing body) 37 of the mold. A fuel tank 38 is disposed between the lower connector 36 and the seat 6. For example, as clearly shown in FIG. 2B, the lower half of the fuel tank 38 is positioned below the control floor 23a, so that the height can be increased to increase the capacity. ing.

  The front end of the mission case 31 and the rear support frame 26 b are connected via a front bracket 39. Therefore, the lower case body of the traveling machine body 1 is constituted by the transmission case 31, the lower coupling body 36, and the rear axle case 34, and the lower structure including the transmission case 31 and the like are composed of the front and rear side frames 9, 10 and the like. The chassis 22 is supported. The lower structure is supported by the front and rear wheels 4 and 5, and the front side frame 9 is also supported by the front wheels 4 as described above.

  In this embodiment, the power steering unit to which the handle post 24 is attached is integrated into the transmission case 31 (that is, the gear case of the power steering unit is integrated into the transmission case 31).

  For example, as shown in FIG. 8, the drive shaft 40 and the work power shaft 41 are arranged on the left and right with the lower coupling body 36 interposed therebetween. The drive shaft 40 drives the rear wheels (if a leveling rotor is provided, this is also driven), and is connected to the transmission case 31 and the rear axle case 34. Needless to say, the rear wheel 5 rotates at the same peripheral speed as the front wheel 4.

  Although it is possible to drive the left and right rear wheels 5 with separate drive shafts, there is a problem that the drive system becomes complicated. On the other hand, when the left and right rear wheels 5 are driven by one drive shaft 40 as in the present embodiment, the drive system can be simplified. When the rear axle case 34 is formed in a U-shape in plan view in which the left and right rearwardly projecting portions 34b are present, the left and right speed reduction mechanisms are allocated to the left and right rearwardly projecting portions 34b, so that space can be used effectively. It can be said. Further, as shown in FIG. 10, it is also possible to easily implement the ground leveling rotor drive shaft 34d to protrude rearward from the base portion 34a.

  The work power shaft 41 drives the seedling planting device 2 (and also drives a fertilizer application device), and is connected to an inter-strain case (not shown). The inter-case is fixed to the lower connecting body and the rear axle case via a bracket, and a planting drive shaft (PTO shaft) and a fertilization drive shaft protrude from the inter-case (not shown).

(2) Connection structure of lower connection body / support structure of chassis Hereinafter, details of each part will be described. First, the connecting structure between the lower connecting body 36 and the transmission case 31 and the connecting structure between the lower connecting body 36 and the rear axle case 34 will be described. This connecting structure is clearly shown in FIGS. 7A and 7B. That is, the front support plate 44 is fixed to the front end of the lower connecting body 36 by welding and is fastened to the rear surface of the transmission case 31 with the bolt 45, and the rear support plate 46 is welded to the rear end of the lower connecting body 36. It is fixed and fastened to the front surface of the rear axle case 34 with bolts 47.

  Although the support plates 44 and 46 are rectangular, any shape can be selected as necessary. As shown in FIG. 9, a male fitting portion 36 a that projects forward of the front support plate 44 is provided at the front end of the lower coupling body 36, while a male fitting portion 36 a is provided on the rear surface of the transmission case 31. A female fitting part (not shown) that fits tightly is formed, and the fitting strength of these male and female fitting parts increases the fastening strength.

  Next, a support structure for the chassis 22 will be described. The lower connecting body 36 and the midframe 11 are connected by a U-shaped reinforcing frame body (reinforcing body) 37 that is manufactured from a round pipe (round steel pipe). For example, as shown in FIG. 5, the mission case 31 is disposed below the upper surface of the front side frame 9 and the upper surface of the midframe 11, and the lower coupling body 36 is fixed to the lower end portion of the mission case 31. Has been.

  The reinforcing frame body 37 is in a forward inclined posture in a side view so that the height decreases as it goes rearward, and left and right upper ends are fixed to the mid frame 11 by welding. Further, as clearly shown in FIG. 7 (C), an upper bracket 48 having a U-shape with a downward opening in front view (or rear view) having left and right downward pieces 48a is fixed to the bottom portion 37a of the reinforcing frame body 37. The lower connecting body 36 is fixed with a lower bracket 49 that is fitted so that the upper bracket 48 is covered, and the upper and lower brackets 48, 49 are connected with left and right horizontally long pins 50.

  As described above, the front end of the mission case 31 and the rear support frame 26 b are connected via the front bracket 39. For example, as can be seen from FIG. 5, the front end of the transmission case 31 is integrally provided with a support portion 53 for connecting to the rear support frame 26 b of the engine support 26, and the front bracket 39 is connected to the support portion 53. ing.

(3). Rear axle case / rear strut As described above, the rear frame 13 forming the rear end portion of the chassis 22 is supported by the left and right rear struts 14, and the left and right rear struts 14 are The axle case 34 is fixed to a stay 35 that is fixed over the left and right rearwardly projecting portions 34b. For example, as shown in FIG. 10, the rear column 14 is fixed to the stay 35 inside the left and right rearward projecting portions 34 b of the rear axle case 34, and the rear frame 13 is located inside the left and right rear side frames 10. Support.

  The rear column 14 uses a square pipe (square steel pipe), and the rear frame 13 and the stay 35 use a round pipe (round steel pipe). For example, as can be understood from FIG. 10, a concave portion that fits into the rear frame 13 from below is formed on the upper end surface of the rear column 14, and an arc-shaped concave portion that fits into the stay 35 from above is formed on the lower end surface. ing. Both upper and lower ends are welded.

  Further, as can be understood from FIG. 5, for example, the rear column 14 is slightly inclined with respect to the vertical line in a side view, and the rearward projecting portion 34b of the rear axle case 34 goes from the base portion 34a to the rear end. It is slightly inclined with respect to the horizontal so as to become lower. The rear frame 13 and the stay 35 may be a square pipe or a steel plate. However, when a round pipe is used as in the present embodiment, even if the rear axle case 34 and the rear column 14 are inclined, There is an advantage that the posture can be easily set (the rear column 14 can be in close contact with the rear column 13 and the stay 35 in any posture).

  For example, as can be clearly seen from FIG. 11, the rear axle case 34 includes a main case 71 having a base 34 a and a rearward projecting portion 34 b, and a side case 72 fixed to the main case 71 from the left and right outer sides with a group of bolts 73. It consists of Accordingly, the side case 72 also has a part of the base part 34a and a part of the rearward projecting part 34b. A gear group is arranged inside the base portion 34a and the rearward projecting portion 34b, but this is omitted in FIG. The side case 72 has a bearing hole 72b, and the rear axle 34c is supported by a bearing mounted in the bearing hole 72b (the rear axle 34c is also supported by a bearing provided on the rearwardly projecting portion 34b of the main case 71). Has been).

  As described above, the stay 35 is fixed in a state where it is passed to the left and right rearwardly projecting portions 34 b of the rear axle case 34. On the other hand, the rearward projecting portion 34b of the rear axle case 34 is composed of a main case 71 and a side case 72, but in this embodiment, the stay 35 is fixed to the side case 72 using a stay bracket 74. . That is, as shown in FIG. 11, two tapped holes 72a are formed on the upper surfaces of the left and right outer cases 72 side by side, and the stay bracket 74 is secured with bolts 75 screwed into the tapped holes 72a from above. Is concluded.

  The bracket 74 for stays has the cylinder part 74a, and the stay 35 is inserted in this cylinder part 74a without the backlash. The stay 35 can be fixed to the cylindrical portion 74a by welding or the like, but it may be simply inserted into the cylindrical portion 74a without any play. As described above, since the stay 35 is merely inserted into the cylindrical portion 74a, even if there is an error in the mounting posture (side view posture) of the rear axle case 34, this error can be absorbed. Can be suppressed.

  A slight clearance is provided between the bolt hole of the bracket 74 for stay and the bolt 75. For this reason, the traveling machine body 1 can be assembled by absorbing processing errors and assembly errors of members such as the rear axle case 34.

(4) Link mechanism / Hydraulic cylinder As can be understood from FIGS. 1 and 12, for example, the link mechanism 3 has a top link 77 and a lower link 78. A hitch 81 is connected to the second pin 80 so as to be relatively rotatable. The seedling planting device 2 is connected to a hitch 81.

  The top link 77 and the lower link 78 are connected to the rear column 14 so as to be vertically rotatable. An intermediate link 82 is connected to the lower link 78 so as to rotate about its rear end portion, and the front end of the intermediate link 82 is supported by an arm 83 projecting from the front end portion of the lower link 78.

  The base end portion of the hydraulic cylinder 30 is connected to a bracket 84 fixed to the lower connecting body 36 by left and right horizontally long pins, so that the hydraulic cylinder 30 rotates up and down around its rear end. The link mechanism 3 is driven by the expansion and contraction of the hydraulic cylinder 30, and thereby the seedling planting device 2 is raised and lowered.

  Further, the link mechanism 3 will be described in detail. The top link 77 is made of a square pipe or a channel material and basically has a linear shape. An upper support cylinder 85 is fixed to the front end of the top link 77 and the upper support cylinder 85 is fixed to the left and right rear columns 14. The support tube 86 is fitted. Accordingly, the top link 77 is connected to the rear column 14 so as to rotate up and down around its front end. A third pin 87 is fitted in the upper support cylinder 86.

  The lower link 78 is substantially Y-shaped with the front end gathered into one and branching backward, and a lower support cylinder 88 is fixed to the front end, and this is fitted to the lower support cylinder 88 fixed to the rear column 14. It is crowded. Accordingly, the lower link 78 is also connected to the rear column 14 so as to rotate up and down around its front end. A fourth pin 89 is fitted in the lower support cylinder 88.

  The intermediate link 82 described above is connected to the lower link 78 by a fifth pin 90 so as to rotate around the rear end portion. The intermediate link 82 has a U-shape with a downward opening when viewed from the front, and a hollow sixth pin 91 is inserted through the front end of the intermediate link 82 in the horizontal direction. On the other hand, the aforementioned left and right arms 83 project upward from the front end portion of the lower link 78, and the sixth pins 91 are supported by the left and right arms 83 from below.

  On the other hand, for example, as shown in FIG. 5, a plate-shaped round hole hook 92 is fixed to the tip of the piston rod 30a in the hydraulic cylinder 30, and the hook 92 and the intermediate link 82 are connected to the sixth pin 91 shown in FIG. It is connected with. Accordingly, when the hydraulic cylinder 30 is extended, the link device 3 is rotated downward and the seedling device 2 is lowered, and when the hydraulic cylinder 30 is contracted, the link device 3 is rotated upward and the seedling device 2 is raised.

(5) Summary In the above configuration, the front end portions of the top link 77 and the lower link 78 constituting the link device 3 are connected to the left and right rear columns 14 by upper and lower support cylinders 86 and 88. Further, since the top link 77 and the lower link 78 are directly connected to each other, the connection structure is simplified.

  Since the rear column 14 is supported by the rearward projecting portion 34b of the rear axle case 34 via the stay 35, the left and right rear columns 14 are set to the minimum left and right intervals that can stably support the rear frame 13. As a result, the upper bearing cylinder 85 provided on the top link 77 and the lower bearing cylinder 88 provided on the lower link 78 can be made as short as possible to ensure high bending strength.

  Further, since the left and right rearward projecting portions 34b are connected by the stay 35, the stay 35 also functions as a reinforcing member for the rear axle case 34. For this reason, the robustness of the rear axle case 34 is also improved. As a result, the overall robustness of the traveling machine body 1 can be improved.

  The rear axle case 34 includes a main case 71 and a side case 72. The rear axle 34c is supported by a bearing provided on the side case 72, so that the stay 35 is temporarily fixed to the main case 71. Then, the load of the traveling machine body acts as an external force that shifts the main case 71 downward with respect to the side case 72. In other words, the load of the traveling machine body 1 acts as an external force (shearing force) that separates the main case 71 and the side case 72.

  On the other hand, when the stay 35 is fixed to the side case 72 as in this embodiment, the load of the traveling machine body 1 is transmitted to the rear axle 34c via the side case 72. It becomes a state close to supporting, and therefore, the load acting on the rear axle case 34 can be reduced and its durability can be improved.

(6). Modification Now, there are irregularities both on the field and on the road. For this reason, for example, the four wheels are supported (grounding resistance), such as traveling with one wheel floating. For this reason, the traveling vehicle body 1 may be subjected to a force that is twisted about the longitudinal longitudinal axis by its own weight. In this regard, when the reinforcing frame 37 is provided as in the embodiment, the rigidity of the structure including the chassis, the transmission case 31, the joint 36, the rear axle case 34, and the rear column 27 is significantly increased. The resistance to torsion can be greatly improved.

  Furthermore, in the modification shown in FIG. 14, a reinforcing function is provided so that the rigidity against torsion can be further improved. That is, in this modification, the left and right side portions of the reinforcing frame 37 are connected by the longitudinal longitudinal stays 94 to increase the rigidity against torsion (of course, the strength against bending is also increased).

  More specifically, a) the reinforcing frame 56, the left and right reinforcing stays 94, and the rear axle case 53 form a substantially rectangular frame in plan view, and b) the reinforcing stay 94 goes rearward in a side view. The rear axle case 34, the reinforcing stay 94, the reinforcing frame 56, and the joint 56 have a three-dimensional truss structure because they are inclined so as to be lowered and extend on an extension line of the rear axle case 53 in the alignment direction of the gear support shafts. Combined with the points that make up, the rigidity against torsion is greatly improved.

  Further, by providing the reinforcing stay 73, the rigidity of the structure including the rear axle case 34, the rear column 14, the rear frame 13, the rear side frame 10, the middle frame 11, and the reinforcing frame 37 has been remarkably improved. This also contributes greatly to increasing the torsional strength of the traveling vehicle body 1.

  The reinforcing stay 94 uses a square steel pipe, and a front auxiliary bracket 95 having an outward U-shape is welded to the front end portion thereof (FIG. 14 is drawn with each member separated, but actually The reinforcing stay 84 is welded to the auxiliary bracket 95.) On the other hand, a substantially L-shaped support bracket 96 in plan view is welded to the left and right sides of the reinforcing frame 37, and the front auxiliary bracket 95 and the support bracket 96 are fastened by a plurality of bolts 97 and nuts 98. .

  Further, a rear auxiliary bracket 99 having a fan shape in side view is welded to the rear end of the reinforcing stay 94, and the rear auxiliary bracket 99 is fixed to the front side surface of the rear axle case 34 with a bolt 100. A receiving seat 101 into which the bolt 100 is screwed is provided on the front side surface of the side case 72 constituting the rear axle case 34. The receiving seats 101 are formed in pairs on the front and rear, and if higher strength is required, the rear auxiliary bracket 99 may be fastened to the four receiving seats 101 (in this case, the reinforcing stay 94 may be thicker). preferable.). Although the support bracket 96 is provided with the side plate 96a only at the rear part, the side plate 96a may be provided at both front and rear ends.

  The torsional force acting on the traveling vehicle body 1 is proportional to the weight of the vehicle body, the distance between the left and right wheels, and the distance between the front and rear wheels. The necessary strength can be ensured without providing a stub, and it can be said that the reinforcement stay 94 may be used in the case of 8-row planting or 10-row planting. Looking at this in reverse, the basic framework of the traveling vehicle body 1 is shared by models with different numbers of planting strips (for example, 4-8 planting, 6-10 planting) (running vehicle body by replacing the joint 36) This means that it is only necessary to use a reinforcing stay 94 if necessary. For this reason, when preparing multiple models with different number of planting lines, manufacturing the entire model group Cost can be suppressed.

  In the present embodiment, the left and right side cases 72 constituting the rear axle case 34 are connected by a stay 35 for supporting a rear column, and the side case 72 and the reinforcing frame 37 are connected by a reinforcing stay 94. In other words, a) a structure composed of left and right rear columns 14, stays 35 and rear frame 13, b) a structure composed of left and right rear side frames 10 and midframe 11, and c) left and right reinforcing stays. 94 and the structure composed of the reinforcing frame 37 are combined to form a composite truss structure, and thus the torsional force acting on the rear axle case 34 is significantly reduced. Thus, the traveling vehicle body 1 has high rigidity. This is one of the advantages of this embodiment.

  The reinforcing stay 73 may use a member having another cross-sectional shape such as a round pipe, and the fixing structure of the reinforcing stay 94 to the reinforcing frame 56 and the rear axle case 53 can be arbitrarily set. The reinforcing stay 94 may be fixed to the middle frame 25 instead of or in addition to fixing to the reinforcing frame 37.

(7). Others This embodiment can be embodied in various ways other than the above embodiments. For example, the application target is not limited to the riding type rice transplanter, but can be applied to other work machines. In the above embodiment, the seedling planting device can be replaced with another working device or a transport cart. Further, the driving means can use a motor instead of the engine.

  The stay and the rear support may not be fixed by welding, but a bracket may be provided and fastened with bolts and nuts. The method of fixing the stay to the rear axle case is not limited to that using the bracket for the stay, and various methods can be adopted. The stay does not necessarily need to be made of pipe, and various modes such as adopting steel mold or sheet metal can be selected.

  The invention of the present application is embodied in a riding-type farm work machine such as a rice transplanter and exhibits utility. Therefore, it can be used industrially.

DESCRIPTION OF SYMBOLS 1 Traveling machine body 2 Seedling planting device as an example of working device 3 Link device 4 Front wheel 5 Rear wheel 9, 10 Side frame 13 Rear frame 14 Rear column 22 Chassis 23 Body cover 25 Engine 30 Lifting hydraulic cylinder 31 Mission case 34 Rear Axle Case 34a Rear Axle Case Base 34b Rear Axle Case Backward Projection 35 Stay 36 Lower Linkage 71 Main Case 72 Side Case 77 Top Link 78 Lower Link

Claims (4)

A rear axle case for transmitting power from a driving source to a rear wheel is disposed below the rear portion of the chassis constituted by a plurality of frame members, and the rear portion of the chassis is arranged on the rear axle case via a rear column. It is equipped with a traveling body that is supported by,
The rear axle case has a base portion and left and right rearward projecting portions and has a substantially U-shaped configuration in plan view, and a rear wheel is supported by the left and right rearward projecting portions, and Left and right horizontally long stays are fixed to the rearward projecting part, and the left and right ends of the stay are fastened to the left and right rearward projecting parts with bolts from above, and the rear support is supported by the stay. doing,
Riding type farm work machine. In front of the rear axle case, a transmission case having a built-in traveling speed change mechanism and left and right front axles is arranged. Front wheels are attached to the front axle, and the transmission case and the rear axle case are arranged. Are connected by a connecting body, and the transmission case and the rear axle case function as a structure of the traveling aircraft body,
The riding type agricultural working machine according to claim 1. The stay is fixed to the upper surface of the left and right rearward projecting portion with a bolt,
The riding type agricultural working machine according to claim 1 or 2. The rear axle case is composed of a U-shaped main case in plan view and a side case that overlaps with the left and right outer sides. Therefore, the left and right side cases are respectively a part of the base and a rearward projecting portion. And the stay is fixed to the side case,
The riding type agricultural working machine according to any one of claims 1 to 3.

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