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1. IN3282/DELNP/2012 - "RIDING-TYPE AGRICULTURAL MACHINE"

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

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RIDING-TYPE AGRICULTURAL MACHINETechnical Field [0001]The present invention relates to a riding-type agricultural machine which is driven by an engine such as a riding-type rice planting machine.Background Art [0002]There is a riding-type rice planting machine as one example of a riding-type agricultural machine. This riding-type rice planting machine includes, as essential elements, a running vehicle body supported by front wheels and rear wheels, and a seedling planting device disposed behind the running vehicle body. The seedling planting device is connected to the running vehicle body such that a height of the seedling planting device can be adjusted. A seat and a steering wheel are disposed on the running vehicle body, and an engine is provided in the running vehicle body. The rice planting machine runs and carries out seedhng planting operation by power from the engine. The running vehicle body can also be called a running portion. [0003]The running vehicle body usually includes a chassis (skeleton framework or machine casing) formed of frame material (steel material) such as steel pipe and channel material. Generally, the running vehicle body includes longitudinally long left and right side frames as essential members1 of the skeleton framework, and the left and right side frames are connected to each other through a laterally long member. A link device is relatively turnably connected to the seedling planting device and the running vehicle body, and the running vehicle body and the link device are connected to each other through a hydraulic cylinder. [0004]The engine can be disposed in front of or behind an operating floor. Patent documents 1 and 2 describe specific examples of the case where the engine is disposed in front of the operating floor. That is, in the patent document 1, left and right side frames configuring a chassis support the engine, and portions of the side frames which support the engine are in horizontal postures. In the patent document 2 on the other hand, front portions of the side frames are formed into inclined portions which become lower forwardly, and a member connected to the inclined portions supports the engine. [0005]A structure similar to the patent document 1 is disclosed in patent document 3. That is, in the patent document 3, left and right side frames 44 are bent such that rear halves thereof become higher rearwardly as viewed from side (i.e., rear halves are formed as inclined portions), front portions of the left and right side frames 44 are connected to each other through a laterally long front frame 41, rear ends of the left and right side frames 44 are fixed to a side surface of an upper portion of a rear frame 43 which rises from a rear axle case 38, and the laterally long rear frame is bent on upper ends of left and right rear columns 43.2 [0006]In the patent document 3, a transmission case 6 extends to the rear axle case 38, and power is transmitted using a contained-type chain disposed in a rear half of the transmission case 6. Longitudinally intermediate portions of the left and right side frames 44 are connected to each other through a mid-frame 175 which penetrates the longitudinally intermediate portions, a bracket 176 is fixed to the mid-frame 175 and the transmission case 6, and a vertically moving cyhnder is connected to the bracket 176.Citation List Patent Literature [0007]Patent Document i: Japanese Patent No.4139669Patent Document 2' Japanese Patent Application Laid-open No.2000-201510Patent Document 3: Japanese Patent No.3804926Summary of Invention Technical Problem [0008]It is preferable that a barycenter of the running vehicle body is lowered as low as possible to secure running body stabihty. Since the engine has a significant weight, to lower a position of the engine is effective for lowering the barycenter of the running vehicle body. In the patent document 2, since a mounting height of the engine can be lowered, the3 barycenter of the running vehicle body can be lowered. However, if the front portions of the side frames are inclined, a support structure of other member supported by the front portions of the side frames must be largely changed, and there is fear that design cost and producing cost of the running vehicle body are increased as a whole. [0009]That is, in the case of the riding-tj^je agricultural machine, as disclosed in Fig. 2 of the patent document 1 for example, a vehicle body cover on which a man rides is disposed in such a stat where the vehicle body cover spreads to both left and right sides of the engine in most cases. A portion of the vehicle body cover which protrudes toward both the left and right sides of the engine is supported directly by the side frames or through a bracket, but if front portions of the side frames are inclined as in the patent document 2, since it is necessary to also change a support structure of the vehicle body cover, design cost and producing cost are increased. [0010]As described in Figs. 1 and 2 of the patent document 1, in the case of a riding-tjT)e agricultural machine, a pair of left and right extra seedling stages are disposed on front portions of the side frames, and the extra seedling stages are fixed to the side frames through brackets in many cases. If the front portions of the side frames are incHned as in the patent document 2, however, since support structures of the extra seedling stages also must be changed, design cost and producing cost of the support portions of the extra seedling stages are increased. [0011]4 It is an object of the invention of this apphcation to improve such circumstances. On the other hand, according to the patent document 3, the transmission case and the rear axle case function as structure materials (strength members) which support other member. Therefore, it can be said that a structure of a running body can be simplified, and cost can be reduced. In a case where the transmission case and the rear axle case are used also as structure materials of the running body as in the patent document 3, it is also an object of the invention of the apphcation to further enhance the rigidity of the running body. [0012]The present application discloses many new configurations, it is a partial object of the application to provide these new configurations. That is, the new configurations disclosed in the application can be independent inventions irrespective whether they are described in claims.Solution to problem [0013]The invention of the application has such a basic configuration that a riding-type agricultural machine includes a running vehicle body on which a man rides to operate the same, and an engine provided in the running vehicle body, the running vehicle body includes a chassis and a running transmission case both disposed below an operating seat, the chassis is formed of frame material, and power is transmitted from the engine to the running transmission case. [0014]5 The present application has many inventions. Among them, a first invention is characterized in that based on the basic configuration, the chassis and the transmission case are disposed in a state where the transmission case is located below the chassis, and one or two member support portions located lower than an upper surface of the transmission case are provided in front of or behind or both in front of and behind the transmission case. As specific examples of the member support portion are a support frame 55 (one example of a front member support portion) for supporting the engine shown in Fig. 3, and a receiving material 38 (one example of a rear member support portion) for supporting a fuel tank shown in Fig. 11(A). [0015]According to a second invention, in the first invention, an engine support on which the engine is placed projects downwardly from a portion of the chassis in front of the transmission case as a front member support portion located in front of the transmission case in a state where a lower end of the engine support is located lower than the upper surface of the transmission case, and the engine is supported by the engine support in a state where a lower surface of the engine downwardly sinks into the chassis. [0016]According to a third invention, in the second invention, the chassis includes left and right side frames extending in a longitudinal direction of the agricultural machine, the side frames are connected to each other through a laterally long frame, and the engine support is provided on front portions of the left and right side frames.6 [0017]According to a fourth invention, in the third invention, the engine support includes one or more support frames which have upwardly opened TJ-shapes as viewed from front, and the engine is mounted on a bottom of the support frame through a buffer body. [0018]According to a fifth invention, in the fourth invention, the number of support frames is two or more, the support frames are arranged rearward and forward, and the support frames are connected to each other through one or more reinforcing bodies projecting toward a location below the support frame. [0019]According to a sixth invention, in the first invention, a front axle device which supports front wheels is connected to the transmission case, and a rear axle case which rotatably supports rear wheels is disposed behind the transmission case, the transmission case and the rear axle case are connected to each other through a lower connecting body located lower than the upper surface of the transmission case, and a rear member support portion (the receiving material 38 for supporting the fuel tank shown in Fig. 11(A) for example) is provided on the lower connecting body behind the transmission case. [0020]According to a seventh invention, in the sixth invention, the chassis includes left and right side frames extending in a longitudinal direction of the agricultural machine, a laterally long mid-frame which connects7 longitudinally intermediate portions of the left and right side frames to each other, and a laterally long rear frame which connects rear ends of the left and right side frames to each other, the rear frame is supported by the rear axle case through a rear column, and the mid-frame or the left and right side frames and the lower connecting body are connected to each other through a reinforcing body. [0021]According to an eighth invention, in the seventh invention, the reinforcing body has an upwardly opened U-shape as viewed from front, the reinforcing body is incUned such that it becomes lower rearwardly as viewed from side, and a fuel tank is supported by a rear member support portion provided on a bottom of the reinforcing body. [0022]According to a ninth invention, in the seventh invention, the reinforcing body is formed of steel pipe and is of a frame structure, and the reinforcing body is formed into a substantially U-shape or V-shape as viewed from front (it is also possible to employ a reversed-trapezoidal shape or a semicircvdar shape). [0023]According to a tenth invention, in the seventh invention, each of the side frames is divided into a substantially horizontal front side frame located in front of the mid-frame and a rear side frame which is located behind the mid-frame and which becomes higher rearwardly, the rear side frame is fixed to the mid-frame at a location laterally inside of the front side frame, and the reinforcing body is fixed to the mid-frame at a location near a front end of the8 rear side frame. [0024]According to an eleventh invention, in the first invention, as a rear member support portion disposed behind the transmission case, an engine support on which the engine is placed is disposed in a state where a lower end of the engine support is located lower than an upper surface of the transmission case, and the engine is supported by the engine support in a state where a lower surface of the engine downwardly sinks into the chassis.Advantageous Effect of Invention [0025]According to the first invention, since the one or two member support portions are provided in front of or behind, or both in front of and behind the transmission case, members (i.e., the engine and the fuel tank) can be disposed in a state where the barycenter is lowered. Hence, the barycenter of the running vehicle body can be lowered and the running body stabiHty can be enhanced. The running vehicle body can also be called a running body portion. [0026]The engine has a significant weight and its height position exerts an influence upon the barycenter of the running vehicle body. Therefore, if the front member support portions support the engine as in the second invention, since the engine is disposed in a state where it downwardly sinks into the chassis, it is possible to reliably lower the barycenter of the running vehicle body. Therefore, this is extremely effective for enhancing the running9 stability. It is possible to select what members should support the enginedepending on kinds and structures of the operating machine.[0027]According to the patent document 2, the front portions of the side frames are inclined. Hence, the patent document 2 can be applied only to a type in which the engine is disposed on a front portion of the chassis. According to the present application, however, as specified in the eleventh invention, it is also possible to dispose the engine support behind the transmission case. In other words, the engine support of the second invention can also be employed as the rear member support portion. Therefore, in the invention of the application, flexibility of the positioning of the engine is high. [0028]In the patent document 2, to lower the support height of the engine, it is necessary to increase the inchnation angle of the frame (chassis) or increase the entire length of the inclined portion, but in the third invention of the apphcation, since the engine support is connected to the chassis, the engine support can be designed without receiving constraints on the chassis. Hence, it is possible to freely set the engine support height without receiving the constraints on the chassis. [0029]According to the third invention of the application, since it is unnecessary to largely change the chassis for providing the engine support, it is unnecessary to largely change the support structure for other members. Hence, even if the engine support is provided, it is possible to prevent or10 suppress the increase of design cost and producing cost. [0030]According to the configuration of the third invention, since the engine support is of a frame structure in which the engine support opens forward and rearward, the engine is of an open structure in which wind impinges on the lower portion of the engine. Hence, when the agricultural machine runs, wind easily impinges on the cylinder block and the cylinder head. As a result, the cooling performance can be enhanced. Further, since the engine support is used also as a frame reinforcing body which connects the left and right side frames to each other, the rigidity of the chassis can be enhanced. [0031]The engine support can be formed of plate metal and it is possible to employ various modes and structures for the engine support, but if the U-shaped support frame as viewed from front is employed as in the fourth invention, there is a merit that the engine can strongly be supported with the simple structure. [0032]In the case of the fourth invention, if the engine is supported from both front and behind, stabihty can be secured. Therefore, it is preferable that a plurahty of support frames are disposed in front of and behind the engine. If the plurality of support frames are provided in front of and behind the engine and they are connected to each other through the reinforcing body as in the fifth invention, the support function of the engine can be secured excellently, and the rigidity of the support frame can remarkably and preferably be enhanced. According to the configuration of11 the fifth invention, since the reinforcing body projects to a location below the support frame, the reinforcing body also functions as a guard which protects the engine, and this is excellent in terms of safety. [0033]According to the sixth invention, the transmission case and the rear axle case can be used also as the strength member for the running body. Hence, the running vehicle body can be reduced in weight and its ruggedness can be secured. The lower connecting body can support a member and a device such as the fuel tank, but since the lower connecting body is located lower than the upper surface of the transmission case, a member to be supported can be disposed as low as possible. As a result, stabihty of the running vehicle body can be enhanced and the running vehicle body can be made compact. [0034]According to the seventh invention, since the side frames or the mid-frame and the lower connecting body are connected to each other, the chassis and the lower structure body reinforce each other and as a result, extremely high rigidity of the running body can be secured. Therefore, even if the rice planting machine is as large as an eight-row or ten-row rice planting machine, high ruggedness can be secured. Since the high ruggedness can be secured, an operating machine other than the planting machine can be mounted on the running body, and a heavy operation can be carried out. The merit capable of securing the ruggedness can be exerted without providing the member support portion. Therefore, the feature that the chassis and the lower connecting body are connected to each other12 through the reinforcing body can be an independent invention. [0035]In the riding-tj^e rice planting machine, the hnk mechanism is turned by the hydrauHc cyhnder and the seedUng planting device is vertically moved as described above, but a large load is naturally applied to the hydraulic cylinder. Therefore, if the cylinder is connected to the lower connecting body as in the embodiment, a large bending load is apphed to the lower connecting body. In the seventh invention of the application, however, since the chassis and the lower connecting body are connected to each other through the reinforcing body, resistance of the lower connecting body against the bending force can remarkably be enhanced. Hence, even if the cylinder is mounted, high strength can be secured. [0036]If the eighth invention is employed, since the fuel tank can downwardly sink into the chassis, there is a merit that the capacity of the fuel tank can be increased. [0037]Various materials such as plate material and molded steel can be used for the reinforcing body, and its mode can variously be developed, but if the ninth invention is employed, the reinforcing body can easily be produced by bending a steel pipe and this is excellent in terms of cost. Loads applied to the left and right front wheels and the left and right rear wheels of the running body usually vary depending upon conditions on a road. A twisting force is applied to the running body due to such uneven loads in many cases. According to the ninth invention, since the reinforcing body is bilaterally13 symmetric, the running body can exert high strength against the twisting. [0038]If the tenth invention is employed, since the front ends of the rear side frames are supported by the reinforcing bodies directly below the front ends, the reinforcing functions of the reinforcing bodies can be exerted more reliably, and the strength is further preferably enhanced.Brief Description of the Drawings [0039]Fig. 1 shows an embodiment and is a side view of an entire rice planting machine in a state where a vehicle body cover is removed;Fig. 2(A) is a plan view of the entire rice planting machine and Fig. 2(B) is a perspective view of a running vehicle body as viewed from side;Figs. 3(A) and 3(B) are perspective views showing a skeleton framework of the running vehicle body;Fig. 4 is a partial separated perspective view of the running vehicle body;Fig. 5(A) is a perspective view of the running vehicle body from which an engine is separated and Fig. 5(B) is a schematic side view of essential portions;Fig. 6 is a separated perspective view showing a support structure of the engine;Figs. 7 show the support structure of the engine, wherein Fig. 7(A) is a separated perspective view of the engine and a support member, Fig. 7(B) is a separated perspective view of a support unit and Fig. 7(C) is a14 perspective view of a buffer unit!Fig. 8(A) is a side view of a front portion of the running vehicle body and Fig. 8(B) is a partial front view of the running vehicle body running vehicle body;Fig. 9(A) is a partial plan view of the front portion of the running vehicle body,'Fig. 10 is a plan view of a modification in a state where some of members are omitted;Fig. 11(A) is a separated perspective view of essential portions, Fig. 11(B) is a perspective view showing a connected state between a lower connecting body and a transmission case and Fig. 11(C) is a perspective view showing a connected state between the lower connecting body and a rear axle case;Fig. 12(A) is a separated side view of essential portions and Fig. 12(B) is a perspective view of a mounting structure of a fuel tank as viewed from below;Fig. 13 is a plan view of a state where the fuel tank is laterally deviated;Fig. 14 is a bottom view of essential portions;Fig. 15 is a partial side view of essential portions;Fig. 16(A) is a separated perspective view of essential portions in a state where the fuel tank is turned over and Fig. 16(B) shows the essential portions as viewed from diagonally behind;Fig. 17 is a partially cut-away side view showing a connecting structure of a link device;15 Fig. 18 is a separated perspective view showing the connecting structure of the hnk device.'Figs. 19 show a modification, wherein Fig. 19(A) is a separated perspective view, Fig. 19(B) is a separated side view, and Fig. 19(C) is a sectional view taken along a line C-C in Fig. 19(B);Figs. 20 show another embodiment, wherein Fig. 20(A) is a side view and Fig. 20(B) is a perspective view;Fig. 21 is a separated perspective view showing further another embodiment; andFig. 22 is a schematic side view showing further another embodiment. Description of Embodiments [0040]Next, an embodiment of the invention of the application wiU be described. The embodiment is applied to a riding-type rice planting machine (simply "rice planting machine", hereinafter). In the following description and claims, words "front, rear" and "left and right" are used for specifying directions. These words are used based on an operator who sits on the rice planting machine while facing a forward moving direction. A direction as viewed from front means a direction as viewed from a direction opposite from the forward moving direction of the rice planting machine. [0041](l) Outline of rice planting machineFirst, outhne of the rice planting machine will be described. As16 shown in Figs. 1 and 2, the rice planting machine includes a running vehicle body 1 and a seedling planting portion 2 as basic elements. The seedling planting portion 2 is vertically movably connected to a rear portion of the running vehicle body 1 through a hnk device 3. The seedling planting portion 2 can be attached to and detached from the link device 3, or the seedling planting portion 2 may not be attached to or detached from the link device 3. [0042]The running vehicle body 1 is supported by left and right front wheels 4 and left and right rear wheels 5, and the front wheels 4 and the rear wheels 5 are driven by power. The rear wheels 5 may be of a double type or of a triple tj^e by adding an auxihary wheel. The running vehicle body 1 includes a seat 6 on which a driver sits. The seat 6 has a backrest. The running vehicle body 1 also includes a steering wheel 7 disposed in front of the seat 6. The seat 6 and the steering wheel 7 are disposed at laterally intermediate positions of the running vehicle body 1. Extra seedling stages 8 (see Figs. 2) are disposed on both left and right sides of the seat 6 and in front of the seat 6. Figs. 2 show only a skeleton framework of the extra seedling stages 8. [0043]As can be understood from Figs. 3 to 5 for example, the running vehicle body 1 includes longitudinally extending left and right front side frames 9 and rear side frames 10. A distance between the left and right rear side frames 10 is narrower than a distance between the left and right front side frames 9. The front and rear side frames 9 and 10 are connected17 to each other through a mid-frame 11. Front portions of the left and right front side frames 9 are connected to each other through a front frame 12. [0044]The rear side frames 10 are incHned such that they become higher rearward as viewed from side, and a laterally long rear frame 13 is connected to rear ends of the left and right rear side frames 10. Left and right rear columns 14 which support the rear frame 13 are fixed to the rear frame 13. The rear columns 14 are disposed inward of the rear side frames 10. Of the frames, the mid-frame 11 and the rear frame 13 are formed of round pipes (round steel pipes), and other frames are formed of angular pipes (angular steel pipes). [0045]A laterally long rear stay 17 is disposed slightly in front of the rear frame 13, the laterally long rear stay 17 is fixed to a hanger bracket 18 (see Figs. 4 and 5) having a U-shape as viewed from front, and the hanger braclset 18 is welded to the rear side frames 10. [0046]A downwardly opened portal (reversed TJ-shape) frame 19 is fixed to the front ends of the left and right rear side frames 10, a front end of a seat support unit 20 (see Fig. l) is fixed to the portal frame 19. A rear portion of the seat support unit 20 is fixed to a stay (not shown). A fuel tank 21 is disposed below the seat 6. If the seat 6 is inchned forward and turned, oil can be supplied into the fuel tank 21. [0047]A plurality of laterally outwardly projecting outward-pointing branch18 frames 15 are fixed to the front side frames 9, and the branch frames 15 support the extra seedhng stages 8. Longitudinally long auxiliary frames 23 are disposed outside the side frames 9 and 10. The auxiliary frames 23 are fixed to the branch frames 15, the laterally long rear stay 17, and the rear frame 13. [0048]In this embodiment, the frame materials such as the fi"ont and rear side frames 9 and 10, the mid-frame 11, the front frame 12, and the rear frame 13 configure the chassis (frame structure body). As shown in Figs. 2, a portion of the running vehicle body 1 on which a man rides is covered with a vehicle body cover 24, and the vehicle body cover 24 is supported by the fi-ont side firames 9, the branch firames 15, the auxiliary frames 23, the laterally long rear stay 17, and the rear frame 13. A fertihzer drive is disposed behind the seat 6 in many cases, but the fertilizer drive is not illustrated in the embodiment. [0049]The steering wheel 7 is mounted on a steering wheel shaft incorporated in a steering wheel post 25. As shown in Figs. 2, a portion of the vehicle body cover 24 which is located between the seat 6 and the steering wheel post 25 is an operating floor 24a on which feet are placed in a state where a man stands or sits, and an engine 26 is disposed in fi-ont of the operating floor 24a (a support structure of the engine 26 will be described later). The engine 26 is covered with a hood from front and behind. [0050]As shown in Figs. 5 for example, a transmission case 27 in which a19 gear group is incorporated is disposed behind the engine 26. As shown in Figs. 3 for example, a hydrostatic static transmission (HST) 28 as one example of a continuously variable transmission is mounted on a left side surface of the transmission case 27, power from the engine 26 is transmitted to the HST 28 through a belt 29 and then, the power is transmitted to the gear group. A clutch and a brake are incorporated in the transmission case 27 in addition to the gear group, but since they are not directly related to the invention of the application, description thereof will be omitted. [0051]As shown in Figs. 5 for example, a tension pulley 30 is in abutment against the belt 29 from below. The tension pulley 30 is mounted on a tip end of a turning type arm 31. A power steering unit 32 is mounted on a front portion of the transmission case 27, and the steering wheel post 25 is fixed to the power steering unit 32. [0052]As shown in Figs. 3 for example, front axle devices 33 are mounted on left and right side surfaces of the transmission case 27, and the front wheels 4 are mounted on the front axle devices 33, respectively. The rear wheels 5 are mounted on a rear axle case 34. The rear axle case 34 includes rearward-pointing left and right protruding portions 34a, and the rear wheels 5 are fixed to axles projecting from the protruding portions 34a. A lateral beam member 35 is inserted into and fixed to the rearward-pointing left and right protruding portions 34a, and the rear columns 14 are fixed to the lateral beam member 35. [0053]20 As can be understood from Figs. 3 to 5, a rear end of the transmission case 27 and a front end of the rear axle case 34 are connected to each other through a lower connecting body (joint) 36 formed of round pipe. The lower connecting body 36 and the mid-frame 11 are connected to each other through a reinforcing frame 37. The rear reinforcing frame 37 is one example of a reinforcing body and has a U-shape as viewed from front. The fuel tank 21 is disposed between the lower connecting body 36 and the seat 6, and the fuel tank 21 is supported by the lower connecting body 36 through a receiving material 38. The receiving material can also be called rear support. [0054]As shown in Figs. 3 and 4, a vertically moving cylinder (hydraulic cylinder) 39 is connected to the lower connecting body 36 through a bracket 40 such that the vertically moving cylinder 39 turns around its front end. The vertically moving cylinder 39 is inclined rearward as viewed from side. The link device 3 shown in Fig. 1 is turned by expanding and contracting motion of the vertically moving cylinder 39 and with this, the seedling planting portion 2 vertically moves. [0055]As shown in Figs. 3 for example, a rear wheel drive shaft 41 is disposed on a left side of the lower connecting body 36, and an operating power shaft 42 is disposed on a right side of the lower connecting body 36. The rear wheels 5 rotate in synchronization with the front wheels 4 of course. When a land readjusting rotor is provided, it is driven by the rear wheel drive shaft 41. The operating power shaft 42 drives the seedling planting21 portion 2 (when the fertihzer drive is provided, it is also driven by the operating power shaft 42). The operating power shaft 42 transmits power to the seedling planting portion 2 through a roots-interval adjusting device 43. [0056](2) Engine and its support structureNext, the engine 26 will be described. The engine 26 in this embodiment is a water-cooled diesel engine, and is laterally mounted in a state where its crankshaft extends laterally. The engine 26 basically has the same configuration as that of the conventional technique. As can easily be grasped firom Fig. 6, the engine 26 includes an engine body 44 in which a crankcase, a cylinder block, and a cylinder head are incorporated, and a radiator 45 disposed on a right side of the engine body 44. [0057]As clearly shown in Fig. 6, an output shaft (crankshaft) 48 of the engine 26 projects from a left side surface of the engine body 44, a flywheel 49 and an output pulley 50 are fixed to the output shaft 48. Power is transmitted to the HST 28 through the belt 29 which is wound around the output pulley 50 (see Figs. 1, 4, 5, and 10). [0058]A silencer 51 is disposed directly on a left side of the flywheel 49. The silencer 51 is disposed between the front side frames 9 and the auxiliary frames 23 as viewed from above, and the silencer 51 is suspended and supported by a stay 52 fixed to the front side frames 9 and the auxiliary frames 23. The silencer 51 is covered with a cover 53 (see Figs. 9).22 [0059]As shown in Figs. 5 for example, a disk 54 located inside the flywheel 49 is fixed to a left side surface of the engine body 44, and the turning t5T)e arm 31 which provided with a tension pulley 50 is mounted on the disk 54 through a bracket. [0060]As clearly shown in Figs. 5 and 6, support frames 55 are connected to substantially front halves of the left and right front side frames 9, and the engine body 44 of the engine 26 is supported by the support frames 55. Each of the support frames 55 is formed of round pipe (round steel pipe), and includes left and right vertical portions (vertically long portions) and a lower horizontal portion connected lower ends of the vertical portions. The support frame 55 has a laterally long IJ-shape as viewed from front. The support frames 55 are mounted in a state where they are suspended from the left and right front side frames 9. The support frames 55 can also be called front supports. [0061]Laterally intermediate portions of the front and rear support frames 55 are connected to each other through a frame reinforcing body (connecting frame) 56, and the support frames 55 and the frame reinforcing body 56 configure an engine support (front member support portion) described in claims. The frame reinforcing body 56 is bent such that it projects downward as viewed from side, and projects downward of the support frames 55. Therefore, the frame reinforcing body 56 functions as a guard for the engine 26.23 [0062]A side bracket 57 is fixed to right sides of the front and rear support frames 55, and the side bracket 57 supports the radiator 45. The radiator 45 is supported by the side bracket 57 through a buffer material such as rubber. The side bracket 57 includes a longitudinally long base portion and inwardly protruding portions which laterally project from both front and rear ends of the base portion. The support frames 55 are welded to lower surfaces of the front side frames 9, but the support frames 55 can also be fixed to inner or outer side surfaces of the front side frames 9 by welding or a bolt. The support frames 55 may be fixed to the front side frames 9 through brackets. [0063]A pair of left and right lower brackets 59 which support the engine 26 are fixed to the lower horizontal portion of each of the front and rear support frames 55 by welding. The front lower brackets 59 extend forward from the front support frame 55, the rear lower brackets 59 extend rearward from the rear support frame 55, and the lower brackets 59 are inchned with respect to a horizontal plane such that tip ends thereof become higher. Therefore, the front and rear lower brackets 59 are inclined such that a distance therebetween becomes narrow downwardly as viewed from side. [0064]On the other hand, as clearly shown in Figs. 7, laterally long upper brackets 60 are fixed to both fi'ont and rear surfaces of a lower portion of the engine body 44 through bolts 61. Each of the upper brackets 60 has a substantially L-shape cross section, support pieces 60a extending in parallel24 to the lower brackets 59 are provided on both left and right ends of the upper brackets 60, and vibration absorbing units 62 are interposed between the support pieces 60a and the lower brackets 59. [0065]Each of the entire vibration absorbing units 62 is integrally formed in a state where a buffer material 65 such as rubber is interposed between an upper plate 63 and a lower plate 64. A bolt 66 penetrates the upper plate 63, the lower plate 64, and the buffer material 65 and a nut 67 is screwed over the bolt 66, thereby fastening the upper brackets 60 and the lower brackets 59 to each other. On the upper plate 63 and the lower plate 64 of the vibration absorbing unit 62, side plates 63a and 64a which function as reinforcing members are formed by bending. The bolt 66 may be fixed to only one of the upper plate 63 and the lower plate 64, or the bolt 66 may merely penetrate both of them. [0066]A round hole 68 into which the bolt 66 of the vibration absorbing unit 62 is fitted is formed in each of the support pieces 60a of the upper bracket 60, and a groove hole 69 into which the bolt 66 of the vibration absorbing unit 62 is fitted is formed in each of the lower brackets 59 by cutting and opening the bracket. It is possible to form a round hole also in the lower bracket 59, but if the method in which the groove hole 69 is formed and the bolt 66 is fitted from front or behind as in the embodiment is employed, there is a merit that the engine 26 can easily be assembled. [0067]In the embodiment, an opening of the groove hole 69 spreads in a25 reversed-tapered shape. Therefore, it is easy to fit the bolt 66. If the front and rear lower brackets 59 are inclined such that the distance therebetween becomes narrower downwardly as viewed from side as in the embodiment, there is a tendency that the engine 26 is held in a position between the front and rear lower brackets 59 by a weight of the engine itself and thus, this is excellent for holding a posture of the engine. [0068]As shown in Fig. 6, a rearwardly projecting rear bracket 70 is connected to a substantially laterally intermediate portion of the rear support frame 55. As shown in Fig. 6, a pin 71 penetrates a tip end of the rear bracket 70, and rear bracket 70 is connected to the transmission case 27 through the pin 71. Therefore, in this embodiment, the transmission case 27 is used also as a structure material (strength member) for the running vehicle body 1. [0069]That is, in this embodiment, the frame materials such as the front and rear left and right side frames 9 and 10, the front frame 12, the mid-frame 11, the rear frame 13, and the rear columns 14 configure the chassis. The chassis, the transmission case 27, the lower connecting body 36, and the rear axle case 34 cooperate with each other to configure the skeleton framework of the running vehicle body 1. [0070](3) SummaryAccording to the above described configuration, the engine 26 downwardly sinks lower than the lower surfaces of the front side frames 9,26 and downwardly sinks lower than the upper surface of the transmission case 27. Since the engine 26 is supported by the support frames 55 in the state where the engine downwardly sinks, the barycenter of the running vehicle body 1 can be lowered and the running stability can be enhanced. [0071]Since the front side frames 9 may be kept in the horizontal postures as they are, when the vehicle body cover 24 or the extra seedling stages 8 are supported, it is only necessary to employ such a simple support structure that the outward branch frames 15 are fixed to the front side frames 9 and the auxiliary frames 23 are fixed to the front side frames 9. Therefore, even if the engine 26 is lowered, peripheral configurations of the engine 26 do not become complicated. [0072]If the support frames 55 fixed to the front side frames 9 support the engine 26 as in this embodiment, since the engine 26 is disposed in a space surrounded by the front frame 12 and the left and right front side frames 9, the front frame 12 and the left and right front side frames 9 function as guards for the engine 26. It can be said that this point is a merit of this embodiment. [0073]The engine 26 can also be disposed vertically such that the crankshaft extends longitudinally, but since it is common that the crankshaft of the engine 26 is long in the axial direction, if the engine is vertically disposed, there is fear that the entire length of the running vehicle body is increased. If the engine 26 is disposed horizontally as in this engine on the27 other hand, there is a merit that it is possible to prevent the running vehicle body 1 from becoming long. It is also possible to easily transmit power to the transmission through the belt 29. [0074]If power from the engine 26 is transmitted to the transmission case 27 (HST 28) through the belt 29, an external force for pulling the engine 26 and the transmission case 27 toward each other is applied to them by the belt 29. In this embodiment, however, since the rear support frame 55 and the transmission case 27 are connected to each other through the rear bracket 70, a distance between the support frames 55 and the transmission case 27 is constantly kept and therefore, the external force for pulhng the support frame 55 rearward is not applied to the support frame 55. As a result, a positional relation between the engine 26 and the transmission case 27 is strongly kept, and a fixing strength of the support frame 55 with respect to the front side frame 9 can be secured. [0075]It is also possible to fix the side bracket 57 on which the radiator 45 is placed to the front side frame 9, but if the side bracket 57 is fixed to the front and rear support frames 55 as in this embodiment, since the side bracket 57 is used also as a reinforcing body which fixes the front and rear support frames 55, there is a merit that ruggedness of the engine support structure body configured mainly by the support frames 55 is remarkably enhanced. [0076](4) Cooling operation of silencerSince the silencer 51 of the engine 26 is heated to high temperature28 by exhaust gas, it is preferable that the silencer 51 is cooled if possible. However, in the conventional technique, no method is devised for cooling the silencer 51 in reality. Nevertheless, if a fan or a duct is provided for cooling the silencer 51, there is a large demerit in terms of cost. [0077]In this embodiment on the other hand, it is possible to cool the silencer 51 while suppressing the increase in cost. That is, the fact that the silencer 51 is disposed lateral to the flywheel 49 is utihzed, and as schematically shown in Fig. 10 as a modification, a coohng fan 72 is fixed to an outer surface of the flywheel 49, and the silencer 51 is cooled by wind from the cooling fan 72. [0078]Since the configuration is such a simple that the cooling fan 72 is merely fixed to the outer surface of the fljrwheel 49, cost is not largely increased. It is also possible to integrally form an air blowing fan on the flj^wheel 49. The silencer 51 may include an afterburner function and an exhaust gas purifying function. [0079](5) Structure of rear half of running vehicle bodyNext, details of a portion of the running vehicle body 1 which is located behind the transmission case 27 will be described. A connecting structure between the lower connecting body 36 and the transmission case 27, and a connecting structure between the lower connecting body 36 and the rear axle case 34 will be described. The connecting structures are clearly shown in Fig. 11(A). That is, a front support plate 74 is fixed to a front end29 of the lower connecting body 36 by welding, this is fastened to a rear surface of the transmission case 27 through a bolt 74', a rear support plate 75 is fixed to a rear end of the lower connecting body 36 by welding, and the rear support plate 75 is fastened to a front surface of the rear axle case 34 through a bolt 75'. [0080]Although the support plates 74 and 75 are rectangular in shapes, any shapes can be selected depending on requirements. As shown in Fig. 15, a male fitting portion 36a projecting forward of the front support plate 74 is provided on a front end of the lower connecting body 36, and a female fitting portion (not shown) to which the male fitting potion 36a is to be tightly fitted is formed in a rear surface of the transmission case 27. These male and female fitting portions are fitted to each other, thereby enhancing the fastening strength. It is also possible to provide fitting portions on and in the lower connecting body 36 and the rear axle case 34. [0081]The reinforcing body 37 is produced using round pipe (round steel pipe). The reinforcing body 37 will be described next. As shown in Fig. 12 for example, the transmission case 27 is disposed lower than an upper surface of the mid-frame 11, and the lower connecting body 36 is fixed to a lower end of the transmission case 27. The gear group is disposed in the transmission case 27 such that heights of the gears are changed in the vertical direction. Hence, the vertical size of the transmission case 27 is extremely large. [0082]30 The lower connecting body 36 is fixed to a lower end of the transmission case 27. Hence, the lower connecting body 36 is disposed much lower than the fi-ont side fi^ames 9 and the mid-fi-ame 11. The rear wheel drive shaft 41 is connected to the rear axle case 34 in such a posture that the rear wheel drive shaft 41 is substantially parallel to the lower connecting body 36 as viewed from side. [0083]The reinforcing flame 37 is inchned forward such that the height of the reinforcing flame 37 becomes lower to a downward direction as viewed from side, and left and right upper ends of the reinforcing flame 37 are fixed to the mid-frame 11 by welding. As clearly shown in Fig. 16(A), downwardly opened groove-shaped receiving materials 38 as viewed from front are fixed to a bottom 37a of the reinforcing frame 37. The receiving materials 38 include left and right downward-pointing pieces 38a. A support bracket 77 to which the receiving materials 38 are fitted is fixed to the lower connecting body 36, and the receiving materials 38 and the support bracket 77 are connected to each other through a laterally long pin 78. A bolt and a nut may be used instead of the pin 78, and the receiving materials 38 and the support bracket 77 may be fastened to each other through the bolt and the nut, or the reinforcing frame 37 can be fixed to the lower connecting body 36 by welding. [0084]A pair of left and right rubber seats 79 are provided on the receiving materials 38, and the rubber seats 79 support a lower surface of the fuel tank 21. As shown in Fig. 16(A), a downward-pointing swelling portion 21a is31 provided on a portion of a lower surface of the fuel tank 21 in front of a portion supported by the rubber seats 79. An outlet 80 for fuel is provided in the downward-pointing swelling portion 21a. Fuel is sent from the outlet 80 to the engine 26 through a filter (not shown). The engine 26 is a diesel type, and fuel is forcibly with a pump sent and therefore, there is no problem even if the outlet 70 of the fuel tank 21 is lower than the engine 26. [0085]As clearly shown in Fig. 12(B), the fuel tank 21 is provided with a pair of front and rear flanges 81 and 82, and the front flange 81 is fixed to a tank bracket 83 through a screw. The tank bracket 83 is fixed to the mid-frame 11. The rear flange 82 of the fuel tank 21 is fastened to a bracket plate 18a through a screw. The bracket plate 18a is provided on the hanger bracket 18 shown in Figs. 4 and 5. A lubrication opening 84 of the fuel tank 21 is located below the seat 6, and if the seat 6 is tilted forward, the lubrication opening 54 is exposed. [0086]As can be understood from Fig. 12(B) for example, a step 85 which opens leftward and forward is formed on an upper surface of the fuel tank 21. A hydraulic unit 86 can be disposed at the location of the step 85 for example. The hydraulic unit 86 controls hydraulic devices such as a hydraulic cylinder 39. Other member may be disposed at the location of the step 85, or the step 85 may not be provided. [0087](6) Link mechanism • hydraulic cylinderNext, the link device 3 and the hydrauHc cylinder 39 will be described.32 As shown in Figs. 17 and 18, the hnk device 3 includes a top link 88 and a lower link 89 which are vertically divided. A hitch 92 is relatively turnably connected to rear ends of both the links 88 and 89 through a first pin 90 and a second pin 91. A king pin (not shown) rearwardly projects from a lower end of the hitch 92, and the seedling planting portion 2 is connected to the lower end of the hitch 92 through the king pin. Therefore, the seedling planting portion 2 can roll through a certain angle with respect to the running vehicle body 1. [0088]The top link 88 is formed of pipe or channel material and is basically straight in shape. An upper bearing cylinder 93 is fixed to a front end of the top link 88, and the upper bearing cylinder 93 is fitted to upper support shafts 94 fixed to the left and right rear columns 14. Therefore, the top link 88 is connected to the rear columns 14 such that the top link 88 vertically turns around its fi-ont end. The upper support shafts 94 are cylindrical in shape, and a third pin 95 is fitted to the upper support shafts 94. [0089]A fi:ont portion of the lower Hnk 89 is one portion, but this portion rearwardly diverges and the lower link 89 has a substantially Y-shape, a lower bearing cylinder 96 is fixed to a front end of the lower link 89, this is fitted to lower support shafts 97 fixed to the rear columns 14 and therefore, the lower Hnk 89 is also connected to the rear columns 14 such that the lower link 89 vertically turns around its front end. Lower support shafts 97 are also cyHndrical in shape, and a fourth pin 98 is fitted into the lower support shafts 97.33 [0090]A longitudinally long intermediate link 99 is connected to the lower link 89 through a fifth pin 100 such that the intermediate link 99 turns around its rear end. The intermediate link 99 has a downwardly opened groove shape. A laterally long hollow sixth pin 101 is inserted into a front end of the intermediate hnk 99. A pair of left and right arms 102 upwardly project from a front end of the lower link 89, and the left and right arms 102 support the sixth pin 101 from below. [0091]On the other hand, the hydraulic cylinder 39 includes a cyhndrical body 39a and a piston rod 39b, and a base end of the cylindrical body 39a is connected to the bracket 40 through a seventh pin 104. The bracket 40 is fixed to the lower connecting body 36. As shown in Fig. 17 for example, a plate-like hook 105 having a round hole is fixed to a tip end of the piston rod 39b, and the hook 105 and the intermediate link 99 are connected to each other through the sixth pin 101 (see Figs. 17 and 18). [0092]Therefore, if the hydraulic cylinder 39 extends, the link device 3 downwardly turns and the seedling planting portion 2 is lowered. If the hydraulic cylinder 39 contracts, the link device 3 upwardly turns and the seedling planting portion 2 rises. A buffer accumulator 106 for cushioning a shock is provided on a tip end of the cylindrical body 39a of the hydraulic cylinder 39. The hydraulic cyhnder 39 may be connected directly to the arms 102 without using the intermediate Unk 99. [0093]34 (7) Summary concerning rear half of running vehicle bodyAs described above, in this embodiment, since the transmission case 27 and the rear axle case 34 are used also as the structure material of the running body 1, the structure of the running vehicle body 1 can be simplified correspondingly, and cost and weight thereof can be reduced (since the transmission case 27 and the rear axle case 34 are strong structures due to their functions, they can exert functions as the strength members). Since the lower connecting body 36 and the mid-frame 11 are connected to each other through the reinforcing fi*ame 37, the lower structure body including the transmission case 27 and the chassis including the side frames 9 and 10 reinforce each other and as a result, the running body 1 becomes an extremely strong structure. [0094]A load of the seedling planting portion 2 is appUed to the hydraulic cylinder 39 as a pulhng force, and a bending force is appUed to the lower connecting body 36 by this pulling force. Since the reinforcing frame 37 stretches against the lower connecting body 36 from above, bending deformation of the lower structure body including the lower connecting body 36 and the transmission case 27 can largely be suppressed and as a result, high durability can be secured. [0095]The fuel tank 21 is surrounded by the reinforcing frame 37 and hence, the height of the fuel tank 21 can be lowered as low as possible irrespective of the existence of the reinforcing frame 37. In this embodiment, since the receiving materials 38 for connecting the reinforcing frame 37 is used also as35 the support member of the fuel tank 21, there is a merit that the structure can be simphfied correspondingly. As shown in Fig. 12(A) for example, a recess 107 for allowing motion of the hydraulic cylinder 39 is formed in a lower surface of the fuel tank 21. Therefore, the fuel tank 21 can be lowered as low as possible without deteriorating the function of the hydraulic cylinder 39. This point is also one of merits of the embodiment. [0096]In this embodiment, each of the side frames is separated into the front side frame 9 and the rear side frame 10, and the front and rear side frames 9 and 10 are connected to each other through the mid-frame 11. Therefore, it is possible to easily change sizes (thicknesses), positions and postures of the front side frames 9 and the rear side frames 10. This point is one of merits of the embodiment. [0097]In this embodiment, the rear columns 14 are supported by the lateral beam member 35 fixed to the rear axle case 34. By using the lateral beam member 35 in this manner, it is possible to reduce a load applied to the rear axle case 34, to enhance the durability, and to freely set a distance between the left and right rear columns 14 without being regvdated by a distance between the rearward-pointing protrusions 34a. [0098](8) Another reinforcing structureUneven spots exist on a field and a road. Hence, supported states (ground-contact resistances) of the four wheels 4 and 5 become unbalance, for example the agricultural machine runs in a state where one of wheels36 floats up. Thus, a weight of the running vehicle body 1 itself is applied as an external force for twisting the running vehicle body 1 around a longitudinal axis thereof in some cases. If the reinforcing frame 37 is provided as in this embodiment, the rigidity of the structure formed of all of the chassis, the transmission case 27, the lower connecting body 36, the rear axle case 34, and the rear columns 14 is remarkably enhanced and therefore, a resistance against the twist is also remarkably enhanced. [0099]As clearly shown in Figs. 19, in this embodiment, a reinforcing function is devised so that the rigidity against the twisting can further be enhanced. That is, both the left and right sides of the reinforcing frame 37 are connected to each other through longitudinally long reinforcing stays 113. The reinforcing frame 37, the left and right reinforcing stays 113, and the rear axle case 34 configure a substantially rectangular framework as viewed from above, thereby enhancing the resistance against the twisting (naturally, the strength against a bending force is also enhanced). [0100]The reinforcing stays 113 are formed of angular steel pipes, and downwardly opened groove-shaped front auxiliary brackets 114 are welded to front ends of the reinforcing stays 113. Substantially, L-shaped support brackets 115 as viewed from above are welded to both left and right sides of the reinforcing frame 37, and the front auxiliary brackets 114 and the support brackets 115 are connected to each other through a plurality of bolts 116 and nuts 117. [0101]37 A rear aiaxiliary bracket 118 having a fan-shape as viewed from side is welded to a rear end of each of the reinforcing stays 113, and the auxiliary bracket 118 is fixed to a side surface of a front portion of the rear axle case 34 through bolts 119. Receiving seats 120 into which the bolts 119 are threadedly inserted are provided on the side surface of the front portion of the rear axle case 34. The pair of receiving seats 120 are formed in each of a front portion and a rear portion. If higher strength is required, the auxiliary bracket 118 may spread rearward as shown with a dashed line, and the auxiliary bracket 118 should be fastened to the four receiving seats 120. [0102](9) Other embodimentsIn an embodiment shown in Fig. 20, in the support mechanism of the engine 26, the frame reinforcing body 56 is formed of plate metal, and a plurality of through holes 56a which vertically open are formed in the frame reinforcing body 56. In this embodiment, since a plane area of the frame reinforcing body 56 is large, rigidity against twisting is high, and a guard function for the engine 26 is also high. Since the through holes 56a exist, the weight can be reduced and venting function can be secured. [0103]In the embodiment shown in Fig. 20, a bumper 122 having a rearwardly opened U-shape as viewed from above is disposed in front of the front support frame 55. The bumper 122 is inclined such that its height is increased forwardly as viewed from side, and left, right, and rear ends of the bumper 122 are welded to the front support frame 55. A front end of the bumper 122 is connected to the front frame 12 through a front bracket 123.38 [0104]A conventional bumper has a merely laterally long shape, and is merely fixed to a firont fi-ame. That is, the conventional bumper merely has a guard function for a front end of a running vehicle body, and does not have other functions. [0105]On the other hand, according to this embodiment, since a bumper 123, the front frame 12, and the front support frame 55 are connected to each other, the ruggedness of the front portion of the chassis is remarkably enhanced. That is, the bumper 123 has a reinforcing function for the chassis (running vehicle body). [0106]Further, since the bumper 122 is fixed to the front support frame 55, the bumper 122 also functions as a protecting member for the engine 26. Hence, although the engine 26 is disposed in a state where the engine 26 downwardly sinks into the fi-ont side fi-ame 9, the protecting function of the engine 26 can further be enhanced (since the ventilation performance is not deteriorated, a cooling function of the engine 26 is also high). In this embodiment, the hydraulic unit 86 is mounted on a rear surface of an upper portion of the transmission case 27 as shown in Fig. 20(A). [0107]Fig. 21 shows another example of the entire framework. In this embodiment, two outer frames 124 are disposed at each of an inner location and an outer location outside the auxiliary firames 23, the outer frames 124 are supported by a plurality of front and rear outer brackets 125. The outer39 frame 124 supports an atixiliary cover 126. A vertically moving step 128 is also fixed to the outside outer frame 124. A rear portion of the vehicle body cover 24 is formed into a high shoulder 24b, and surrounding frames (safety pahsade) 127 are disposed around the step 24b. The left and right surrounding frames 127 are fixed to the outside outer frame 124. [0108]The outer frame 124 is disposed in state where it largely protrudes laterally outward of the side frames 9 and 10. A pair of left and right sticks 128 extending laterally outward from the lower connecting body 36 are provided, and the sticks 128 support the outer bracket 125 located on the rear end. Hence, ruggedness of a portion on which a man rides can remarkably be enhanced. The sticks 128 are connected to a bracket fixed to the lower connecting body 36. [0109]In an embodiment shown in Fig. 22, the engine 26 is disposed behind the transmission case 27. In this embodiment, the transmission case 27 and the rear axle case 34 are connected to each other through the lower connecting body 36 Hke the previous embodiment, and have a front reinforcing body 37 and a rear reinforcing body 37'. The rear reinforcing body 37' is fixed to a laterally long frame 130 connected to the left and right rear side frames 10. The reinforcing bodies 37 and 37' are mounted on the lower connecting body 36 through brackets, but they may be mounted directly on the lower connecting body 36 by welding or by means of bolts. [0110]A bottom plate 131 is mounted on the front and rear reinforcing40 bodies 37 and 37', and the engine 26 is supported by the bottom plate 131 through vibration absorbing rubbers (not shown). The front and rear reinforcing bodies 37 and 37' have IJ-shapes as viewed from front. In this embodiment, the fuel tank can be disposed in front of the transmission case 27. [0111]The front and rear reinforcing bodies 37 and 37' may be formed into substantially L-shapes as viewed from front having horizontal portions of vertically long portions, and tip ends of the horizontal portions may be fixed to a side surface of the lower connecting body 36. Lower horizontal portions of the reinforcing bodies 37 and 37' formed into TJ-shapes as viewed from front may be fixed to a lower surface of the lower connecting body 36. The front reinforcing body 37 may be fixed to a portion of the mid-frame 11 outside the rear side firames 10. [0112](10) Other informationThe invention of the application can variously be embodied in addition to the above-described embodiments. For example, the invention is not Hmited to the riding-tj^e rice planting machine, and can also be applied to other riding-type agriciiltural machines such as a seedling transplanting machine and a mower. The seedhng planting portion of the embodiment can be applied to other operating device or a conveying truck. The runnning body method of the running body is not limited to the method using the wheels, and a running method using a crawler can also be employed.41 [0113]It is unnecessary that the side frame is separated into front and rear independent members, and the entire side frame may be connected as one member. The mode of the reinforcing body connected to the mid-frame and the lower connecting body is not limited, and various modes can be employed. The lower connecting body may be formed of a round pipe or a plurality of pipes and many variations can be employed. When a hydraulic cylinder is connected to the lower connecting body, it is possible to connect the transmission case and the mid-frame or the side frame to each other and in this case also, the same effect as that of the invention of the application can be exerted.Industrial Applicability [0114]The invention of the application can be embodied for a riding-t5T)e agricultural machine such as a rice planting machine, and has high utility. Therefore, the invention can be applied industrially.Reference Signs List [0128]1 Running vehicle body2 Seedling planting portion as on example of operation machine3 Link device4 Front wheels5 Rear wheels42 9 Front side frame11 Mid-frame12 Front frame13 Rear frame21 Fuel tank24 Vehicle body cover24a Operating floor26 Engine27 Transmission case38 Receiving portion as one example of rear member support portion39 Hydraulic cylinder55 Support frame configuring engine support as one example of front member support portion56 Frame reinforcing body configuring engine support43