JP6515009B2 - Work vehicle - Google Patents

Description

  For example, the present invention relates to a working vehicle such as a farm work machine such as a tractor or a combine, a crane car, or a special work machine such as a backfour.

  2. Description of the Related Art Conventionally, some working vehicles such as agricultural vehicles such as tractors and combines and construction machines such as crawler cranes are equipped with two hydraulic continuously variable transmissions (HST) to which power from the engine is transmitted. One type of continuously variable transmission is configured to output straight driving power and turning power based on the engine output. The applicant of the present invention previously proposed in Patent Document 1 a work vehicle that can be turned by combining the straight-ahead power and the turning power output from each of the two hydraulic continuously variable transmissions with the left and right planetary gear mechanisms. ing.

  In addition, some conventional work vehicles include a hydraulic mechanical transmission (HMT) having a transmission efficiency higher than that of a hydraulic continuously variable transmission in a transmission case to which power is transmitted from an engine. The applicant previously filed an in-line hydraulic mechanical transmission in which the hydraulic pump and the hydraulic motor were arranged in series such that the input shaft of the hydraulic pump and the output shaft of the hydraulic motor were concentrically located. Patent Document 2 proposes.

  In an in-line hydro-mechanical transmission, an output shaft is fitted rotatably on an input shaft to which power is transmitted from an engine. Furthermore, the hydraulic pump, the cylinder block and the hydraulic motor are fitted on the input shaft. The cylinder block independently serves both for the hydraulic pump and for the hydraulic motor, and power is transmitted from the hydraulic motor to the output shaft. For this reason, in a serial type hydraulic mechanical transmission, unlike a general hydraulic mechanical transmission, it is possible to combine hydraulic shift power and engine power without intervention of a planetary gear mechanism and to output high power. It has the advantage that transmission efficiency can be obtained.

Japanese Patent Application Laid-Open No. 2002-059753 Japanese Patent Application Laid-Open No. 2005-083497

  By the way, in order to mount the hydro-mechanical transmission in Patent Document 2 on a medium- or large-sized work vehicle, it is necessary to increase the output of the hydro-mechanical transmission. In order to increase the output of the hydro-mechanical transmission, for example, the capacity of the hydro-mechanical transmission can be increased. However, simply increasing the capacity of the hydraulic mechanical transmission not only increases the size of the hydraulic mechanical transmission itself and increases the manufacturing cost, but also sacrifices the power transmission efficiency (especially the efficiency in the low load range) There was a problem that.

  In addition, even when the mechanism in Patent Document 1 is mounted on a large work vehicle, the mechanism becomes larger as the output of the hydraulic continuously variable transmission increases, so that the weight of the work vehicle is not only increased, but also power transmission Since the efficiency is lower than that of the hydraulic mechanical transmission, the shift range in the straight direction (main shift range) is limited. Furthermore, when two hydraulic mechanical transmissions are disposed before and after the traveling vehicle, there is a limit in connection of the hydraulic piping, and it may be difficult to increase the output due to the hydraulic loss due to the hydraulic piping.

  This invention makes it a technical subject to provide the work vehicle which examined and improved the present condition as mentioned above.

  The work vehicle according to the present invention includes an engine mounted on a traveling airframe, a linear transmission case including a linear transmission path including a first continuously variable transmission, and a turning transmission path including a second continuously variable transmission. In a working vehicle including a rotating transmission case, and combining the output of the straight traveling transmission path and the output of the rotating transmission path to drive the left and right traveling units, hydraulic oil is applied to the second continuously variable transmission. A first hydraulic pipe to be circulated is extended from the transmission case for straight movement toward the transmission case for turning, and the first hydraulic pipe is the traveling body outside the traveling body on the transmission case side for straight movement. On the transmission transmission case side, and is disposed on the inner side of the traveling body on the turning transmission case side, and the miss for the turning is provided through a filter provided on the inner side of the traveling body. Is that is connected to Nkesu.

  In the work vehicle described above, the turning transmission case is configured such that a rear case for incorporating a gear mechanism for outputting power to the left and right traveling units and a front case for incorporating the second continuously variable transmission are connected. A partition plate installed in the traveling body is provided above the turning transmission case and at a connection position between the front case and the rear case, and the first hydraulic pressure is generated by the partition plate. The pipe may be fixed in the middle, and the filter may be suspended and supported by the traveling machine body in front of the turning transmission case.

  In the work vehicle described above, support brackets for supporting the work machine mounted in front of the traveling body are fixed to the left and right sides of the traveling body, and a pair of left and right connected to both sides of the rear case of the turning transmission case. The axle case is connected to the left and right pair of support brackets, and the first hydraulic piping is disposed inside the traveling body at a position overlapping the support bracket in the front-rear direction. Good.

  In the work vehicle, the traveling portion is a traveling crawler, and a lower frame supporting the track frame front of the traveling crawler is suspended and supported on the lower side of the traveling body and is connected to the support bracket It is good also as things.

  In the work vehicle described above, a third hydraulic pressure connected to a second hydraulic pipe for supplying a portion of the hydraulic oil in the transmission case for going straight to the work machine and a work machine valve mechanism for switching the hydraulic oil into and out of the work machine. A piping connection member for connecting the second hydraulic piping and the third hydraulic piping, and the work machine valve mechanism may be fixed to one of the left and right support brackets. Good.

In the work vehicle, the third hydraulic pipe is disposed on the outer side of the traveling body along the traveling body and rearward of the support bracket, and the traveling body disposed above the straight transmission case. It may be connected to a hydraulic circuit of a hydraulic external takeout mechanism that supplies hydraulic fluid to a hydraulically driven work machine that is detachably mounted on the.

  According to the present invention, the hydraulic piping can be efficiently arranged along the traveling body, and the filter having a large pressure loss can be disposed in the vicinity of the transmission case having the continuously variable transmission, so that the hydraulic loss due to the hydraulic piping can be reduced. Power transmission efficiency by the continuously variable transmission can be enhanced. As a result, since a sufficient output can be obtained by the hydraulic device, it is possible to prevent a decrease in traveling speed, a stop of work, and the like due to a lack of power at the time of work even in a medium to large work vehicle. As a result, high output can be achieved without increasing the capacity of the hydraulic device, and the space occupied by the hydraulic device in the work vehicle can be reduced, and as a result, the installation area of the engine which is a power generation source is expanded or The freedom of design in the work vehicle is increased, such as being able to widen the living space of the

It is a left side view of a tractor. It is a right side view of a tractor. It is a top view of a tractor. It is a right side view of a run body. It is a left side view of a run body. It is a top view of a run body. It is the perspective view seen from the right rear of a run body. It is the perspective view seen from the right side front of a run body. It is the perspective view seen from the left front of a run body. It is the perspective view seen from the left rear of a run body. It is a plane explanatory view of a control seat part. It is a perspective view which shows the connection structure of a brake mechanism and a brake pedal. It is a skeleton diagram of a power transmission system of a tractor. It is a hydraulic-circuit figure of a tractor. It is a front enlarged perspective view of a traveling body. It is a front expansion perspective view inside a traveling body. It is an enlarged perspective view which shows the structure of the support bracket periphery provided in the traveling body front. It is the perspective view seen from the lower side which shows the structure inside a traveling body. It is a top view which shows the piping route of hydraulic piping in a tractor. It is a left view of the transmission case for rectilinear advance. It is a top view of the transmission case for rectilinear advance. It is a perspective view showing the composition around the right fuel tank. It is a perspective view which shows the structure around a left fuel tank. It is an exploded perspective view of a run body.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 1 to 10, the traveling machine body 2 of the tractor 1 is supported by a pair of traveling crawlers 3 as a traveling unit. A diesel engine 5 (hereinafter simply referred to as an engine) is mounted on a front portion of the traveling body 2, and the tractor 1 is configured to travel forward and backward by driving the traveling crawler 3 by the engine 5. The engine 5 is covered by a bonnet 6. A cabin 7 is installed on the upper surface of the traveling body 2. Inside the cabin 7 are disposed a steering seat 8 and a steering handle 9 for steering the traveling crawler 3. At the left and right outer sides of the cabin 7, steps 10 for getting on and off by the operator are provided. A fuel tank 11 for supplying fuel to the engine 5 is provided on the left and right lower sides of the cabin 7, and the fuel tank 11 is covered by left and right rear fenders 21. A battery 817 for supplying power to the front of the fuel tank 11 is provided on the left side of the cabin 7 and is covered by the left rear fender 21 together with the fuel tank 11.

  As shown in FIGS. 1 to 10, the traveling airframe 2 comprises an engine frame 14 having a front bumper 12 and a transmission case 13 for turning, and left and right airframe frames 15 detachably fixed to the rear of the engine frame 14 ing. The axle 16 is rotatably protruded outward from the left and right ends of the turning transmission case 13, and an axle case 90 covering the axle 16 is provided on the left and right sides of the turning transmission case 13. Sprockets 62 are attached to the left and right ends of the turning transmission case 13 via axles 16. The rear portion of the machine body frame 15 is connected to a straight transmission case 17 for transmitting the rotational power from the engine 5 to the sprocket 62 by appropriately shifting the rotational power.

  A hydraulic lift mechanism 22 for lifting and lowering a ground work machine (not shown) such as a rotary tiller is detachably mounted on the rear of the straight transmission case 17. The ground working machine is connected to the rear of the straight transmission case 17 via a three-point link mechanism 111 consisting of a pair of lower links 23 and a top link 24 on the left and right. A PTO shaft 25 for transmitting a PTO driving force to a working machine such as a rotary tiller is provided on the rear side surface of the straight transmission case 17 so as to protrude rearward.

  The left and right engine frame (front frame) 14 has its front end inner side surface connected to the left and right outer side surfaces of the frame connecting member 12a, and the front bumper 12 is fixed in front of the frame connecting member 12a. The frame connecting member 12a is made of a rectangular metal casting, and the diesel engine 5 is supported on the engine frame 14 constructed by the frame connecting member 12a. A frame bottom plate 233 is bridged by the upper edges of the left and right engine frames 14 and the upper surface of the frame connecting member 12 a so as to cover the upper end of the front end side of the engine frame 14. At the lower edge of the engine frame 14, an undercover 296 covering the lower side of the turning transmission case 13 is installed rearward from the front end of the engine frame 14. The undercover 296 has its front end connected to the lower surface of the frame connecting member 12a, while its left and right side edges are connected to the left and right engine frames 14, respectively.

  A radiator 235 having a fan shroud 234 mounted on the rear side is erected on the frame bottom plate 233 so as to be located on the front side of the engine 5. The fan shroud 234 surrounds the outer peripheral side of the cooling fan 206, and communicates the radiator 235 with the cooling fan 206. On the front side of the radiator 235, a rectangular frame-like frame frame 226 is provided upright on the frame plate 233. An intercooler 220, an oil cooler 274, a condenser 275, etc. are installed in the frame frame 226, and an air cleaner 221 is installed at an upper position on the front surface of the frame frame 226. 273 is installed.

  The front end sides of the left and right airframe frames 15 are connected to the rear end sides of the left and right engine frames 14, and the left and right airframe frames 15 are disposed so as to sandwich the left and right engine frames 14. Supporting beam frames 236 are connected to the middle portions of the left and right paired vehicle body frames 15. The fuselage frame 15 has a front end coupled to the rear end of the engine frame 14, a midway portion coupled to the end face (outer surface) of the support beam frame 236, and a rear end coupled to the straight transmission case 17. The support beam frame 236 is bolted to each of the left and right body frames 15 to bridge the left and right body frames 15, and the engine support frame 237 is mounted on the upper surface thereof. The lower end surface of the engine support frame 237 is bolted to the upper surface of the support beam frame 236 so as to surround the flywheel 26 of the diesel engine 5 together with the support beam frame 236.

  As shown in FIGS. 1 to 10, in the diesel engine 5, a cylinder head is mounted on a cylinder block incorporating an engine output shaft 5a (see FIG. 12) and a piston, and an intake manifold is disposed on the right side surface of the cylinder head. On the other hand, the exhaust manifold is disposed on the left side surface of the cylinder head. That is, in the engine 5, the intake manifold and the exhaust manifold are divided and arranged on both side surfaces along the engine output shaft 5a. The cooling fan 206 is disposed on the front surface of the cylinder block of the diesel engine 5, while the flywheel 26 is disposed on the rear surface of the cylinder block. That is, the flywheel 26 and the cooling fan 206 are distributed and disposed on both sides of the engine 5 that intersect with the engine output shaft 5 a.

  A flywheel 26 is mounted on a rear end of an output shaft (piston rod) 5a (see FIG. 12) of the engine 5 projecting rearward from a rear side surface of the engine 5 so as to be directly coupled. The main driving shaft 27 protruding backward from the flywheel 26 and the input counter shaft 28 protruding forward from the front side of the straight transmission case 17 are connected via a power transmission shaft 29 having free shaft joints at both ends. . A straight forward input counter that protrudes backward from the turning transmission case 13 via a power transmission shaft 31 having free shaft joints at both ends on a straight forward output shaft 30 that protrudes forward from the lower front of the straight forward transmission case 17 The shaft 508 is connected. An output shaft (piston rod) 5a at the front end of the engine 5, which projects forward from the front side of the engine 5, projects rearward from the turning transmission case 13 via a power transmission shaft 711 having universal shaft joints at both ends. A turning input counter shaft 712 is connected.

  Front engine legs (engine mounts) 238 having anti-vibration rubber are bolted to the left and right side surfaces of the cylinder block of the engine 5, respectively. An engine leg 238 is bolted to an upper portion of an engine support bracket 298 connected to the middle of the left and right engine frames 14. The diesel engine 5 is held between the engine frame 14 by a pair of left and right engine legs 238 to support the front side of the diesel engine 5. The diesel engine 5 is connected to the upper surface of the engine support frame 237 via an engine leg (engine mount) 240 having anti-vibration rubber, at an upper portion of the rear surface of the flywheel housing 60. The rear surface of the diesel engine 5 is connected to the front end side of the left and right pair of airframe frames 15 via the support beam frame 236, the engine support frame 237, and the engine leg body 240, and the airframe frame 15 front end It is made to support the side.

  As shown in FIGS. 1 to 10, the left and right track frames 61 are disposed on the lower surface side of the traveling body 2. The track frame 61 extends in the front-rear direction and is provided as a pair on the left and right sides, and is positioned on the outer sides of the engine frame 14 and the machine body frame 15. The left and right track frames 61 are connected to the engine frame 14 and the airframe frame 15 by lower frames 67 extending in the left-right direction. The front ends of the left and right track frames 61 are connected to an axle case 90 provided on the left and right sides of the turning transmission case 13. At the outside of each of the left and right track frames 61, a step 10a on which the operator gets on and off is provided.

  The left and right center portions of the lower frame 67 are fixed to the rear side surface of the engine frame 14 via the connection bracket 72. The left and right ends of a beam frame 68 extended in the left-right direction are connected to the front and rear middle portions of the left and right track frames 61. The rear beams 73 projecting inward at the rear of the left and right track frames 61 are connected to the rear housing 74 fixed on the left and right sides of the straight transmission case 17 so that the rear of the track frame 61 corresponds to the left and right sides of the straight transmission case 17 Fix it.

  The track frame 61 includes a drive sprocket 62 for transmitting the motive power of the engine 5 to the traveling crawler 3, a tension roller 63 for maintaining the tension of the traveling crawler 3, and a plurality of track rollers for holding the ground side of the traveling crawler 3 in a grounded state. An intermediate roller 65 for holding the non-grounded side of the traveling crawler 3 is provided. The drive sprocket 62 supports the front side of the traveling crawler 3, the tension roller 63 supports the rear side of the traveling crawler 3, the track roller 64 supports the grounded side of the traveling crawler 3, and the intermediate roller 65 does not support the traveling crawler 3. Support the ground side. The tension roller 63 is rotatably supported by the rear end of a tension frame 69 which is configured to be extensible and contractible rearward from the rear end of the track frame 61. The track roller 64 is rotatably supported at the front and rear of the equalizer frame 71 supported at the lower part of the track frame 61 so as to be able to swing back and forth.

  Further, a front dozer 80 is configured to be attachable to the front of the tractor 1. A pair of left and right dozer brackets 81 are fixed to the front side of the engine frame 14, the axle case 90 and the lower frame 67, and the U-shaped (U-shaped) support arms 83 of the front dozer 80 are left and right. It is detachably pivoted to the outside (airside) of the dozer bracket 81. The left and right dozer brackets 81 are connected to the side surfaces of the left and right engine frames 14 at the front end inner side (inboard side), and are connected to the upper surface of the lower frame 67 midway portion at the rear end, and the midway portion is the axle case 90 midway portion It is connected so as to be held at the top and bottom. The dozer bracket 81 is firmly fixed to the engine frame 14, the axle case 90, and the lower frame 67, so that the strength which can withstand heavy work by the front dozer 80 can be secured.

  The front doser 80 includes a pair of left and right connecting frames 82 bolted to the left and right pair of dozer brackets 81 respectively (outer side), and the left and right rear ends of the support arm 83 configured substantially in a U shape in plan view The end is pivotally supported at the front lower portion of the left and right connecting frames 82 so as to be vertically pivotable. A pair of left and right lifting cylinders 85 are interposed between the front upper portion of the left and right support frame 82 and the upper end of the left and right sides of the support arm 83 so that the support arm 83 can be raised and lowered by the expansion and contraction of the lift cylinder 85.

  At the front end of the support arm 83, a blade 84 is provided via a blade attachment 88. The blade mounting body 88 is pivotally supported at the left and right center of the support arm 83 so as to be rotatable left and right, and the blade 84 is tiltably supported at the front surface of the blade mounting body 88. An inclined cylinder 87 is interposed between the upper left and right center of the blade 84 and one of the left and right sides of the blade mounting body 88, and the expansion and contraction of the inclined cylinder 87 enables the blade 54 to be inclined. A pair of left and right angle cylinders 86 are interposed between the left and right side rear parts of the support arm 83 and the left and right sides of the blade mounting body 88, and extend the left and right angle cylinders 86 in opposite directions to make the blade mounting body 88 left and right. It is possible to rotate. In this way, the blade 84 can be moved up and down and inclined forward and backward and inclined up and down.

  As shown in FIGS. 1 to 10, a cabin 7 covering a control seat 8 located on a traveling body 2 includes a cabin frame 300 constituting a framework. The cabin frame 300 includes a pair of left and right front struts 301 located forward of the steering seat 8, a pair of left and right rear struts 302 located rearward of the steering seat 8, and a front beam connecting upper ends of the front struts 301 with each other. A member 303, a rear beam member 304 connecting between the upper ends of the rear columns 302, and a left and right side beam member 305 connecting between the upper ends of the front columns 301 and the rear columns 302 arranged in the front and rear direction It has a box shape. A roof body 306 is detachably mounted on the upper end side of the cabin frame 301, that is, on the rectangular frame formed by the front beam member 303, the rear beam member 304, and the left and right side beam members 305.

  The left and right outer end sides of the front lower plate member 307 extending inward in the left and right direction are connected to the lower end side of each front support column 301. A vertically long board support plate 901 for fixedly supporting the dashboard 33 is connected to the left and right inner end sides of the left and right front lower plate members 307, and the board support plate 901 is erected between the left and right front struts 301. On the other hand, a rear intermediate beam member 309 extending in parallel to the rear beam member 304 is connected between lower ends of the left and right rear columns 302. The upper end sides of a pair of left and right rear lower frames 310 extending downward are connected to the rear intermediate beam member 309.

  The longitudinal direction end portions of the bottom frame 311 extending in the front and rear direction are connected to the front lower plate plate 307 arranged in the front and rear direction and the lower end side of the rear lower frame 310. The floor plate 40 is stretched on the upper surface side of the left and right bottom frames 311, the dashboard 33 is erected on the front end side of the floor plate 40, and the steering handle 9 is mounted on the rear surface side of the dashboard 33 via the steering column 32. . The brake pedal 35 and the like are disposed on the front upper surface side of the floor plate 40, and the control seat 8 is attached to the rear upper surface side of the floor plate 40.

  The cabin 7 is supported by the traveling airframe 2 via the left and right front supports 96 and the left and right rear supports 97. The front support 96 is bolted to the front end of the outboard surfaces of the left and right airframe frames 15, and the front bottom of the cabin 7 is supported by the anti-vibration rubber body 98 on the upper surface of the front support 96 doing. Further, the rear support base 97 is bolted to the outer side surface of the rear housing 74 provided on the left and right of the transmission case 17 for going straight, and the rear side of the cabin 7 via the anti-vibration rubber body 99 on the upper surface side of the rear support base 97. The bottom part is supported by vibration isolation. Therefore, the cabin 7 is supported by the traveling body 2 in a vibration-proof manner via the plurality of vibration-proof rubber bodies 98, 99.

  The tank frame 18 is fixed to the upper surface of the left and right rear supports 97 and supported by the rear housing 74 via the rear supports 97. That is, the pair of left and right tank frames 18 are distributed to the left and right of the cabin 7 and fixed to the traveling body 2 at a position above the crawler 3. In each of the left and right tank frames 18, two supporting column frames 290 are provided upright on a tank mounting plate 289 on which the fuel tank 11 is placed. The supporting column frame 290 is provided on the cabin 7 side, and the fuel tank 11 is installed on the top surface of the tank mounting plate 289 and outside the supporting column frame 290 (outboard side). Then, the other end of the band 286 whose one end is connected to the upper end of the supporting column frame 290 is fixed to the tank mounting plate 290, so that two places on the front and back of the fuel tank 11 are on the tank mounting plate 289 by the band 286. Bonded fixed.

  A battery 817 is installed in one of the left and right tank frames 18 (in the present embodiment, the left tank frame 18). The battery 817 is disposed in front of the fuel tank 11, and a battery mounting plate 291 is extended on the front side of the tank mounting plate 289 of the tank frame 18. The lower side of the battery mounting plate 291 is connected to a reinforcing frame 292 connected to the front side surface of the rear support 97, and the battery 291 is supported with high rigidity.

  The fuel tank 11 and the battery 817 mounted on the left and right tank frames 18 are covered by the rear fender 21 below the cabin 7, and the rear fender 21 functions as a tank cover. One of the left and right rear fenders 21 (in the present embodiment, the left rear fender 21) covers the battery 817 together with the fuel tank 11, and the front side on which the battery 817 is installed A door 21a is provided. The battery open door 21a is provided at a front position corresponding to the battery 817, and is opened rearward and outward by a hinge member that is also received inside the rear fender 21. By opening the battery open door 21a, the battery 817 installation position of the rear fender 21 can be largely opened, so that various maintenance operations including replacement of the battery 817 become easy.

  The left and right fuel tanks 11 separately disposed to the left and right below the cabin 7 are communicated with the fuel communication pipe 281 at the front lower side and one of the left and right fuel tanks 11 (in the present embodiment, the right fuel A filler port 283 is provided at the upper position of the tank 11). As a result, the fuel supplied from the fuel supply port 283 to one fuel tank 11 is also supplied to the other fuel tank 11 through the fuel communication pipe 281.

  Further, one of the left and right rear fenders 21 (in the present embodiment, the right rear fender 21) is provided with a refueling open door 21b at the upper rear position thereof and corresponding to the refueling port 283. The refueling open door 21b is opened rearward and outward by a hinge member that is also received inside the rear fender 21. Therefore, even when the fuel supply open door 21b is open, when the door of the cabin 7 is opened, the fuel supply open door 21b does not collide. Furthermore, by arranging the fuel supply port 283 of the fuel tank 11 and the battery 817 on the left and right sides, not only the opening area of the rear fender 21 can be suppressed and strength reduction can be prevented, but the operator can easily identify the doors 21a and 21b. Become.

  Breather hoses 331 and 332 that open the inside of the fuel tank 11 to the atmosphere are piped along the cabin frame 300 to the rear upper side. Specifically, a breather hose 331 connecting the upper surfaces of the left and right fuel tanks 11 is extended to the left and right along the rear intermediate beam member 309. The breather hose 331 is connected to a breather hose 332 connected to the upper surface of one fuel tank 11 (in the embodiment, the right fuel tank 11) on the lower side of the connection portion between the rear column 302 and the rear intermediate beam member 309 The air in the tank 11 is joined by the breather hoses 331 and 332. The breather hose 332 is extended upward along the rear support column 302 from the connection position with the breather hose 331. The upper end of the breather hose 331 is buried in the roof body 306 to prevent rainwater from being applied to the breather hose 331 and to prevent the rainwater from entering the fuel tank 11.

  An oil / water separator 215 for supplying fuel in the fuel tank 11 to the diesel engine 5 and an auxiliary fuel pump 216 are disposed on a tank frame 18 on which one of the left and right fuel tanks 11 is mounted. In the present embodiment, the fuel filter 217 is disposed on the right side of the engine 5, and the oil / water separator 215 and the auxiliary fuel pump 216 are fixed to the right tank frame 18. That is, since the battery 817 is also installed in the left tank frame 18, the oil / water separator 215 and the auxiliary fuel pump 216 can not only be effectively arranged in the large right tank frame 18 of the installation space, but also the same side as the fuel filter 217 By arranging the oil / water separator 215 and the auxiliary fuel pump 216 in the above, the efficiency of the piping work of the fuel supply passage can be improved. The oil / water separator 215 is suspended and supported by the rear support column frame 290 of the tank frame 18, while the auxiliary fuel pump 216 is mounted and fixed on the upper surface of the tank mounting plate 289 and on the front side of the fuel tank 11 There is.

  As shown in FIGS. 1 to 10, the hydraulic lifting mechanism 22 lifts the fulcrum to the upper surface lid of the left and right hydraulic lift cylinders 117 which are operated and controlled by the operation of the working part position dial 51 etc. The left and right lift arms 120 pivotally support the proximal end side via a shaft and the left and right lift rods 121 connecting the left and right lift arms 120 to the left and right lower links 23 are provided. A part of the right lift rod 121 is formed by a horizontal cylinder 122 for hydraulic pressure control, and the length of the right lift rod 121 is configured to be adjustable by extension and contraction by the horizontal cylinder 122. If the piston of the horizontal cylinder 122 is extended and contracted to change the length of the right lift rod 121 under the condition that the ground work machine is supported by the top link 24 and the lower links 23 on the left and right, the right and left tilt of the ground work machine It is configured to change the angle.

  Next, the internal structure of the cabin 7 will be described with reference to FIGS. 11 and 12 and the like. A steering column 32 is disposed in front of the steering seat 8 in the cabin 7. The steering column 32 is erected in such a manner as to be embedded on the back side of the dashboard 33 disposed on the front side inside the cabin 7. On the upper end side of the steering wheel shaft projecting upward from the top surface of the steering column 32, a steering handle 9 having a substantially circular shape in plan view is attached.

  On the right side of the steering column 32, a brake pedal 35 for braking the traveling body 2 is disposed. On the left side of the steering column 32, the forward / reverse switching lever 36 (reverser lever) for switching the traveling direction of the traveling vehicle 2 between forward and reverse, and the power connection clutch (not shown) are disconnected. A clutch pedal 37 is disposed. On the rear side of the steering column 32, a parking brake lever 43 for holding the brake pedal 35 in a depressed position is disposed.

  An erroneous operation preventing body 38 (reverser guard) extending along the forward and reverse travel switching lever 36 is disposed below the forward and reverse travel switching lever 36 on the left side of the steering column 32. By arranging the erroneous operation preventing body 38, which is a contact preventing tool, below the forward / reverse switching lever 36, when the user gets on / off the tractor 1, the operator is prevented from inadvertently contacting the forward / reverse switching lever 36. On the back upper side of the dashboard 33, an operation display panel 39 incorporating a liquid crystal panel is provided.

  An accelerator pedal 41 for controlling the rotational speed or the vehicle speed of the engine 5 is disposed on the right side of the steering column 32 in the floor plate 40 in front of the steering seat 8 in the cabin 7. Note that substantially the entire top surface of the floor plate 40 is formed flat. Side columns 42 are disposed on the left and right sides of the control seat 8. Between the control seat 8 and the left side column 42, an ultra low speed lever 44 (creep lever) for forcibly and significantly reducing the traveling speed (vehicle speed) of the tractor 1, and a traveling auxiliary shift in the straight transmission case 17 An auxiliary transmission lever 45 for switching the output range of the gear mechanism and a PTO transmission lever 46 for switching the driving speed of the PTO shaft 25 are disposed.

  Between the control seat 8 and the right side column 42, there is provided an arm rest 49 for mounting the arm and elbow of the operator seated on the control seat 8. The arm rest 49 is configured separately from the control seat 8 and is a main transmission lever 50 for increasing and decreasing the traveling speed of the tractor 1 and a dial type for manually changing and adjusting the height position of the work implement such as a rotary tiller And a work unit position dial 51 (lifting dial). The arm rest 49 is configured to be able to flip up and rotate in multiple stages with the lower end of the rear end as a fulcrum. Further, in the present embodiment, the vehicle speed of the traveling machine body 2 increases when the main shift lever 50 is tilted forward, while the vehicle speed of the running body 2 decreases when the main shift lever 50 is tilted backward.

  The right side column 42 has an operation monitor 55 having a touch panel function and capable of instructing each part of the tractor 1 in order from the front side, a throttle lever 52 for setting and holding the rotational speed of the engine 5, and a PTO shaft 25 PTO clutch switch 53 for switching power transmission from the motor to a work machine such as a rotary cultivator, and a plurality of hydraulic control levers for switching the hydraulic external takeout valve 430 disposed on the upper surface side of the straight transmission case 17 54 (SCV lever) and a single double acting change switch 56 for switching the double acting valve mechanism 431 arranged on the front surface of the rear housing 74 are arranged. Here, the hydraulic pressure extraction valve 430 is for supplying and controlling hydraulic oil to hydraulic equipment of another working machine such as a front loader attached to the tractor 1 later. The double acting valve mechanism 431 is for operating the lift cylinder 117 in a double acting manner by operating in conjunction with the lift valve mechanism 652 disposed on the upper surface side of the straight transmission case 17.

  Next, the relationship between the brake pedal 35 and the brake mechanism 751 will be described mainly with reference to FIG. In front of the steering column 32, a brake pedal support bracket 916 for supporting the brake pedal shaft 755 is fixed to the back surface of the board support plate (air cut plate) 901 (the steering seat 8 side). The base end boss portion 35 a of the brake pedal 35 is fitted on the brake pedal shaft 755, and the base end boss portion 35 a of the brake pedal 35 is connected to rotate integrally with the brake pedal shaft 755. A forwardly projecting pedal shaft arm 756 is fixed to both ends of the brake pedal shaft 755, and the pedal shaft arm 756 rotates with the brake pedal shaft 755.

  On the left and right lower sides of the board support plate (air cut plate) 901, a pair of left and right brake operation shafts 757 are supported. A link boss body 758 connected to the braking arm 752 of the brake mechanism 751 in the turning transmission case 13 is rotatably fitted on the left brake operation shaft 757. Link arm 759 provided on the outer peripheral surface of link boss 758, lower end of vertically extending link rod 762 connected to left pedal shaft arm 756, and two-stage expansion and contraction in which braking operation of brake mechanism 751 is stepwise The upper end of the link body 763 is connected. The lower end of the two-stage telescopic link body 763 is connected to the tip of the link arm 767 at the rear end of the brake rod 766. The brake rod 766 is supported by link support brackets 764 and 765 fixed to the engine frame 14 and extends in the front-rear direction. The link arm 768 at the front end of the brake rod 766 is connected to the braking arm 752 of the brake mechanism 751 in the turning transmission case 13 via the connection plate 753.

  That is, the left end of the brake pedal shaft 755 is connected to the brake arm 752 of the brake mechanism 751 via the link rod 762, the two-stage telescopic link body 763, and the brake rod 766. Therefore, as the brake pedal shaft 755 is rotated as the brake pedal 35 is depressed, the braking arm 752 can be rotated, and the braking operation by the brake mechanism 751 can be performed. At this time, when the step amount of adjusting the traveling speed is small due to the action of the two-stage expansion / contraction link body 763 as compared with the case where there is a small amount of depression (play area of the brake mechanism 751) In the braking region), the depression force on the brake pedal 35 becomes large.

  A link boss body 760 having a link arm 761 is rotatably fitted on the right brake operation shaft 757. The upper end of a two-stage telescopic link body 769 for stepping on the brake pedal 35 is connected to the right pedal shaft arm 756, and a two-stage link arm 761 is provided protruding on the outer peripheral surface of the link boss 760. The lower end of the expandable link body 769 is connected. When the brake operation shaft 757 is turned in accordance with the depression of the brake pedal 35, the two-step telescopic link body 769 acts, whereby the amount of depression for adjusting the traveling speed is small (compared to the play area of the brake mechanism 751). When the amount of depression applied suddenly is large (the braking area by the brake mechanism 751), the depression force on the brake pedal 35 becomes large.

  Next, the internal structure of the transmission case 17 for going straight and the transmission case 13 for turning and the power transmission system of the tractor 1 will be described mainly with reference to FIGS. 12 to 14. In the front chamber of the transmission case 17 for linear movement, a mechanical creep transmission gear mechanism 502 for shifting rotational power via a hydraulic mechanical continuously variable transmission 500 for linear movement and a forward-reverse switching mechanism 501 to be described later A transmission gear mechanism 503 is disposed. A forward / reverse switching mechanism 501 for switching the rotational power from the hydraulic mechanical continuously variable transmission 500 in the forward or reverse direction is disposed in the intermediate chamber of the straight transmission case 17. A PTO transmission mechanism 505 is disposed in the rear room of the straight transmission case 17 for appropriately shifting the rotational power from the engine 5 and transmitting it to the PTO shaft 25. The creep transmission gear mechanism 502 and the traveling auxiliary transmission gear mechanism 503 correspond to a traveling transmission gear mechanism that performs multi-speed shifting of the transmission output via the forward / reverse switching mechanism 501. A pump case 480 containing a working machine hydraulic pump 481 and a traveling hydraulic pump 482 driven by the rotational power of the engine 5 is attached to the front right side of the straight transmission case 17.

  A flywheel 26 is directly connected to an output shaft 5 a of the engine 5 protruding rearward from the rear side surface of the engine 5. An input countershaft 28 projecting forward from the front side of the straight transmission case 17 is connected to a main driving shaft 27 projecting backward from the flywheel 26 via a power transmission shaft 29 having a universal shaft joint at both ends. The rotational power of the engine 5 is transmitted to the input counter shaft 28 of the transmission case 17 for straight advance via the main driving shaft 27 and the power transmission shaft 29, and the hydraulic mechanical continuously variable transmission 500 and the creep transmission gear mechanism 502 or the traveling The transmission gear mechanism 503 appropriately shifts the gear. The transmission power via the creep transmission gear mechanism 502 or the travel auxiliary transmission gear mechanism 503 is transmitted to the gear mechanism in the turning transmission case 13 via the front output shaft 30, the power transmission shaft 31, and the straight forward input counter shaft 508. Be done.

  The hydraulic mechanical type continuously variable transmission (HMT) 500 for straight advance has the main transmission output shaft 512 concentrically arranged on the main transmission input shaft 511, and the hydraulic pump portion 521, the cylinder block and the hydraulic motor portion 522 are connected in series. It is a serial type (inline type) arranged in A main transmission input gear 513 is fitted on the rear end side of the input counter shaft 28 so as not to allow relative rotation. On the rear end side of the main shift input shaft 511, an input transmission gear 514 which is always meshed with the main shift input gear 513 is fixed. Therefore, the rotational power of the input counter shaft 28 is transmitted to the hydraulic mechanical continuously variable transmission 500 via the main transmission input gear 513, the input transmission gear 514 and the main transmission input shaft 511. A main transmission high-speed gear 516, a main transmission reverse gear 517, and a main transmission low-speed gear 515 are fitted on the main transmission output shaft 512 such that relative rotation is not possible. The input side of the main shift input shaft 511 and the output side of the main shift output shaft 512 are located on the same side (the rear side as viewed from the hydraulic mechanical continuously variable transmission 500).

  The hydraulic mechanical continuously variable transmission 500 includes a variable displacement hydraulic pump unit 521 and a fixed displacement hydraulic motor unit 522 operated by high pressure hydraulic fluid discharged from the hydraulic pump unit 521. The hydraulic pump portion 521 is provided with a pump swash plate 523 capable of changing the inclination angle with respect to the axis of the main shift input shaft 511 to adjust the hydraulic oil supply amount. The pump swash plate 523 is interlocked with a main shift hydraulic cylinder 524 for changing and adjusting the inclination angle of the pump swash plate 523 with respect to the axis of the main shift input shaft 511. In the embodiment, the main transmission hydraulic cylinder 524 is assembled to the hydraulic mechanical continuously variable transmission 500, and is unitized as one member.

  When the main shift hydraulic cylinder 524 is driven in proportion to the operation amount of the main shift lever 50, the inclination angle of the pump swash plate 523 with respect to the axis of the main shift input shaft 511 is changed accordingly. The pump swash plate 523 according to the embodiment adjusts the angle within a range between one (positive) maximum inclination angle and the other (negative) maximum inclination angle across a neutral angle of approximately zero inclination (the zero before and after the zero). It is possible, and when the traveling vehicle 2 is at the lowest speed, it is set to an angle inclined to either one (in this case, an inclination angle near the maximum and at the maximum).

  When the inclination angle of the pump swash plate 523 is substantially zero (neutral angle), the hydraulic pump unit 521 does not push and pull the input side plunger group. Although the cylinder block rotates in the same direction and at substantially the same rotational speed as the main shift input shaft 511, no hydraulic oil is supplied from the hydraulic pump portion 521, so the output side plunger group of the cylinder block and hence the hydraulic motor portion 522 are not driven. The main shift output shaft 512 rotates at substantially the same rotational speed as the main shift input shaft 511.

  When the pump swash plate 523 is inclined in one direction (a positive inclination angle or a normal rotation inclination angle) with respect to the axis line of the main transmission input shaft 511, the hydraulic pump portion 521 is an input side plunger group Is pushed and pulled to supply hydraulic oil to the hydraulic motor unit 522, and the hydraulic motor unit 522 is rotated in the same direction as the main shift input shaft 511 via the output side plunger group of the cylinder block. At this time, since the cylinder block rotates in the same direction as the main transmission input shaft 511 and at substantially the same rotational speed, the main transmission output shaft 512 rotates at a rotational speed faster than the main transmission input shaft 511. That is, the rotational speed of the hydraulic motor unit 522 is added to the rotational speed of the main shift input shaft 511 (which may be referred to as the rotational speed of the cylinder block), and transmitted to the main shift output shaft 512. As a result, in the range of rotational speed higher than the rotational speed of the main transmission input shaft 511, the main transmission output is proportional to the inclination angle of the pump swash plate 523 (which may be referred to as a positive inclination angle or a normal rotation inclination angle). The transmission power of the shaft 512 is changed. When the pump swash plate 523 is positive and at an inclination angle near the maximum, the main transmission output shaft 512 rotates at a high speed, but the traveling airframe 2 is at an intermediate speed corresponding to the middle from the lowest speed (approximately zero) to the highest speed. Become.

  When the pump swash plate 523 is inclined in the other direction (which may be referred to as a negative inclination angle or a reverse inclination angle) with respect to the axis of the main transmission input shaft 511, the hydraulic pump portion 521 The hydraulic motor unit 522 is pushed and pulled to supply hydraulic oil to the hydraulic motor unit 522, and the hydraulic motor unit 522 is rotated in the opposite direction to the main transmission input shaft 511 via the output side plunger group of the cylinder block. At this time, since the cylinder block rotates in the same direction as the main shift input shaft 511 and at approximately the same rotational speed, the main shift output shaft 512 rotates at a lower rotational speed than the main shift input shaft 511. That is, the rotational speed of the hydraulic motor unit 522 is subtracted from the rotational speed of the main shift input shaft 511 (which may be referred to as the rotational speed of the cylinder block), and transmitted to the main shift output shaft 512. As a result, in the range of rotational speed lower than the rotational speed of the main shift input shaft 511, the main shift output shaft is proportional to the inclination angle of the pump swash plate 523 (which may be referred to as negative inclination angle or reverse inclination angle). The 512 shift power is changed. When the pump swash plate 523 is negative and at an inclination angle near the maximum, the main transmission output shaft 512 is at the lowest speed (approximately zero).

  A pump drive gear 484 is non-rotatably fitted on a pump drive shaft 483 for driving both of the work implement and traveling hydraulic pumps 481 and 482. The pump drive gear 484 couples the main transmission input gear 513 of the input counter shaft 28 so as to allow power transmission via the spur gear mechanism 485. Further, the straight transmission case 17 is provided with a lubricating oil pump 518 for supplying hydraulic oil for lubrication to the hydraulic mechanical continuously variable transmission 500, the forward / reverse switching mechanism 501, and the like. The pump gear 520 fixed to the pump shaft 519 of the lubricating oil pump 518 always meshes with the input transmission gear 514 of the main transmission input shaft 511. Therefore, the working machine and traveling hydraulic pumps 481 and 482 and the lubricating oil pump 518 are driven by the rotational power of the engine 5.

  Next, the switching structure between forward and reverse performed through the forward and reverse switching mechanism 501 will be described. On the rear side of the input counter shaft 28, a planetary gear mechanism 526 which is a forward high speed gear mechanism and a low speed gear pair 525 which is an forward low speed gear mechanism are disposed. The planetary gear mechanism 526 includes a sun gear 531 that rotates integrally with the input transmission gear 529 rotatably supported on the input counter shaft 28, and a carrier 532 that rotatably supports a plurality of planetary gears 533 on the same radius. And a ring gear 534 having internal teeth on the inner circumferential surface. The sun gear 531 and the ring gear 534 are rotatably fitted on the input counter shaft 28. The carrier 532 is fitted on the input counter shaft 28 in a non-rotatable manner. The sun gear 531 meshes with the planet gears 533 of the carrier 532 from the inner radius. Further, the internal teeth of the ring gear 534 mesh with the respective planetary gears 533 from the radially outer side. An output side transmission gear 530 integrally rotating with the ring gear 534 is also rotatably supported on the input counter shaft 28. The input-side low-speed gear 527 and the output-side low-speed gear 528 that constitute the low-speed gear pair 525 are integrally formed, and can rotate between the planetary gear mechanism 526 and the main shift input gear 513 of the input counter shaft 28 It is supported.

  A traveling relay shaft 535 and a traveling transmission shaft 536 extending in parallel with the input counter shaft 28, the main shift input shaft 511 and the main shift output shaft 512 are disposed in the straight transmission case 17. A forward / reverse switching mechanism 501 is provided on a traveling relay shaft 535 as a transmission shaft. That is, the traveling relay shaft 535 is provided with a forward high speed gear 540 connected by a wet multiplate type forward high speed hydraulic clutch 539, a reverse gear 542 connected by a wet multiplate type reverse hydraulic clutch 541, and a wet multiplate A forward low speed gear 538 connected by a forward low speed hydraulic clutch 537 of a mold is fitted. A traveling relay gear 543 is fitted non-rotatably between the forward high-speed hydraulic clutch 539 and the reverse gear 542 in the traveling relay shaft 535. A traveling transmission gear 544 always meshing with the traveling relay gear 543 is fitted on the traveling transmission shaft 536 such that relative rotation is not possible. The main transmission low speed gear 515 of the main transmission output shaft 512 is constantly meshed with the input low speed gear 527 of the low speed gear pair 525 on the input countershaft 28 side, and the output low speed gear 528 is always meshed with the forward low speed gear 538. The main transmission high speed gear 516 of the main transmission output shaft 512 always meshes with the input transmission gear 529 of the planetary gear mechanism 526 located on the input countershaft 28 side, and the output transmission gear 530 always meshes with the forward high speed gear 540. The main transmission reverse gear 517 of the main transmission output shaft 512 always meshes with the reverse gear 542.

  When the forward / reverse switching lever 36 is operated to the forward side, the forward low-speed hydraulic clutch 537 or the forward high-speed hydraulic clutch 539 is in a power connection state, and the forward low-speed gear 538 or the forward high-speed gear 540 and the traveling relay shaft 535 are connected relatively nonrotatably Be done. As a result, forward low speed or forward high speed rotational power is transmitted from the main transmission output shaft 512 to the traveling relay shaft 535 via the low speed gear pair 525 or the planetary gear mechanism 526, and power from the traveling relay shaft 535 to the traveling transmission shaft 536 It is transmitted. When the forward / reverse switching lever 36 is operated to the reverse side, the reverse hydraulic clutch 541 is in a power connection state, and the reverse gear 542 and the traveling relay shaft 535 are coupled so as to be relatively non-rotatable. As a result, the rotational power of reverse travel is transmitted from the main transmission output shaft 512 to the traveling relay shaft 535 via the main transmission reverse gear 517 and the reverse gear 542, and the power is transmitted from the traveling relay shaft 535 to the traveling transmission shaft 536.

  The forward low speed hydraulic clutch 537 or the forward high speed hydraulic clutch 539 is determined to be in the power connection state by the forward operation of the forward / reverse switching lever 36 in accordance with the operation amount of the main shift lever 50. Further, when the forward / reverse switching lever 36 is in the neutral position, all the hydraulic clutches 537, 539, 541 are in the power disconnection state, and the traveling drive force from the main shift output shaft 512 is substantially zero (the main clutch disconnection state )become. On the other hand, when the main shift lever 50 is operated to be neutral regardless of the operation state of the forward / reverse switching lever 36, the pump swash plate 523 is negative by the drive of the main shift hydraulic cylinder 524 and the tilt angle near the maximum (reverse tilt angle). Thus, the main shift output shaft 512 and the traveling relay shaft 535 are in the lowest speed rotation state (approximately zero). As a result, the vehicle speed of the tractor 1 becomes substantially zero.

  When the main shift lever 50 is operated from neutral to medium speed by the drive of the main shift hydraulic cylinder 524, the pump swash plate 523 is negative and maximum when the main shift lever 50 is operated from the neutral position to the middle speed while the forward / reverse selector lever 36 is moved forward. It changes from a near inclination angle (reverse rotation inclination angle) to a positive and maximum inclination angle near normal (normal rotation inclination angle) through zero, and the shift power from hydraulic motor unit 522 to main shift output shaft 512 is approximately from zero Speed up to high speed. At this time, the forward low-speed hydraulic clutch 537 is in a power connection state, and the forward low-speed gear 538 or the forward high-speed gear 540 and the traveling relay shaft 535 are connected so as not to be relatively rotatable. As a result, the rotational power of forward low speed is transmitted from the main transmission output shaft 512 to the traveling relay shaft 535 via the low speed gear pair 525, and the traveling relay shaft 535 rotates at the lowest speed by the accelerating power to the main transmission output shaft 512. It changes from the state to the forward intermediate speed rotation state. Then, power is transmitted from the traveling relay shaft 535 to the traveling transmission shaft 536.

  When the main shift lever 50 is operated to accelerate from the intermediate speed to the maximum speed in a state where the forward / reverse switching lever 36 is operated to the forward side, the inclination angle near positive and at the maximum by driving the main shift hydraulic cylinder 524 The pump swash plate 523 changes its power from the hydraulic motor section 522 to the main shift output shaft 512 from high speed from (the normal rotation inclination angle) to a negative and maximum inclination angle (reverse rotation inclination angle) through zero through zero. Slow down to approximately zero. At this time, the forward high-speed hydraulic clutch 539 is in a power connection state, and the forward high-speed gear 540 and the traveling relay shaft 535 are coupled so as not to be relatively rotatable. As a result, forward high-speed rotational power is transmitted from the main transmission output shaft 512 to the traveling relay shaft 535 via the planetary gear mechanism 526. That is, after the power from engine 5 and the decelerating power to main transmission output shaft 512 are combined in planetary gear mechanism 526, traveling relay shaft 535 is rotated from the forward intermediate speed rotation state to the maximum forward speed rotation state by the combined power. Change. Then, power is transmitted from the traveling relay shaft 535 to the traveling transmission shaft 536. The traveling body 2 is at the highest speed.

  When the main transmission lever 50 is operated from neutral to acceleration while the forward / reverse switching lever 36 is operated to the reverse side, the pump swash plate 523 is negative by the drive of the main transmission hydraulic cylinder 524 and the inclination angle near the maximum It changes from (reverse rotation inclination angle) to a positive and maximum inclination angle (forward rotation inclination angle) through zero, and accelerates the shift power from the hydraulic motor 522 to the main transmission output shaft 512 from substantially zero to high speed Let At this time, the reverse hydraulic clutch 541 is in a power connection state, and the reverse gear 542 and the traveling relay shaft 535 are coupled so as not to be relatively rotatable. As a result, the rotational power of reverse travel is transmitted from the main transmission output shaft 512 to the traveling relay shaft 535 via the main transmission reverse gear 517 and the reverse gear 542, and the traveling relay shaft 535 is accelerated by the main transmission output shaft 512. Changes from the lowest speed rotation state to the reverse high speed rotation state. Then, power is transmitted from the traveling relay shaft 535 to the traveling transmission shaft 536.

  Next, the switching structure between ultra low speed, low speed and high speed which is executed via the creep transmission gear mechanism 502 which is a traveling transmission gear mechanism and the traveling auxiliary transmission gear mechanism 503 will be described. A mechanical creep transmission gear mechanism 502 and a traveling auxiliary transmission gear mechanism 503 for shifting rotational power via the forward / reverse switching mechanism 501, and a traveling counter coaxially extending with the traveling transmission shaft 536 in the transmission case 17 for linear movement. A shaft 545 and an auxiliary transmission shaft 546 extending parallel to the traveling counter shaft 545 are disposed.

  A transmission gear 547 and a creep gear 548 are provided on the rear side of the traveling countershaft 545. The transmission gear 547 rotatably fits on the traveling counter shaft 545 and is coupled to the traveling transmission shaft 536 so as to rotate integrally therewith. The creep gear 548 is rotatably fitted on the traveling counter shaft 545. Between the transmission gear 547 and the creep gear 548 of the travel counter shaft 545, a creep shifter 549 is spline-fit so as to be relatively non-rotatable and to be slidable in the axial direction. By turning on and off the ultra low speed lever 44, the creep shifter 549 slides and the transmission gear 547 and the creep gear 548 are alternatively connected to the traveling counter shaft 545. A reduction gear pair 550 is rotatably fitted on a portion of the auxiliary transmission shaft 546 in the front chamber. The input side reduction gear 551 and the output side reduction gear 552 constituting the reduction gear pair 550 are integrally formed, and the transmission gear 547 of the travel counter shaft 545 is always meshed with the input side reduction gear 551 of the auxiliary transmission shaft 546 The creep gear 548 is constantly meshed with the output side reduction gear 552.

  A low speed relay gear 553 and a high speed relay gear 554 are provided on the front side of the traveling countershaft 545. The low speed relay gear 553 is fixed to the traveling counter shaft 545. The high speed relay gear 554 is fitted on the traveling counter shaft 545 so as not to be relatively rotatable. A low speed gear 555 meshing with the low speed relay gear 553 and a high speed gear 556 meshing with the high speed relay gear 554 are rotatably fitted on the auxiliary transmission shaft 546 on the front side of the reduction gear pair 550. Between the low speed gear 555 and the high speed gear 556 of the auxiliary transmission shaft 546, the auxiliary transmission shifter 557 is spline-fit so as to be non-relatively rotatable and slidably in the axial direction. By operating the sub shift lever 45, the sub shift shifter 557 slides, and the low speed gear 555 and the high speed gear 556 are alternatively connected to the sub shift shaft 546.

  Furthermore, a relay shaft for straight drive 568 and a straight drive shaft 30 extending in parallel with the traveling counter shaft 545 and the auxiliary transmission shaft 546 are disposed. A driven gear 570 fitted non-rotatably to the relay shaft 568 for rectilinear advance is always meshed with the main moving gear 569 fitted non-rotatably to the front end side of the auxiliary transmission shaft 546. The straight advance output gear 583 fitted to the straight advance output shaft 30 non-rotatably is engaged with the straight advance relay gear 582 fitted non-rotatably to the rear end side of the straight advance relay shaft 568. The main transmission gear 569 of the auxiliary transmission shaft 546, the driven gear 570 and the relay relay gear 582 for the linear movement relay shaft 568, and the linear output gear 583 of the output shaft 30 for linear movement rotate the auxiliary transmission shaft 456 straight. A straight forward output gear mechanism 509 for transmitting power to the output shaft 30 is configured.

  In the embodiment, creep gear 548 is connected to travel counter shaft 545 so as not to be able to rotate relative to travel counter shaft 545 when super low speed lever 44 is operated while secondary transmission lever 45 is operated to the low speed side. Relatively non-rotatably connected, the traveling drive force at an ultra-low speed from the straight output shaft 30 is directed to the turning transmission case 13 via the traveling transmission shaft 536, the traveling counter shaft 545, the auxiliary transmission shaft 546 and the relay shaft 568 for straight traveling. Output.

  When the ultra low speed lever 44 is turned off and the sub transmission lever 45 is operated to the low speed side, the transmission gear 547 is connected non-rotatably to the travel counter shaft 545 and the low speed gear 555 can not be rotated relative to the sub transmission shaft 546 Connected to the traveling transmission shaft 536, the traveling counter shaft 545, the auxiliary transmission shaft 546, the relay shaft 568 for straight traveling, etc., and the ultra low speed traveling drive force is output toward the turning transmission case 13 from the straight output shaft 30. Be done.

  When the ultra low speed lever 44 is turned off and the sub transmission lever 45 is operated to the high speed side, the transmission gear 547 is connected to the traveling counter shaft 545 so as not to be relatively rotatable, and the high speed gear 556 is impossible to relatively rotate to the sub transmission shaft 546 Connected to the traveling transmission shaft 536, the traveling counter shaft 545, the auxiliary transmission shaft 546, the relay shaft 568 for rectilinear advance, etc., and the traveling drive force of high speed is output from the output shaft 30 for straight travel toward the transmission case 13 for turning. Ru.

  The power transmission shaft 31 connects the straight forward input counter shaft 508 that projects backward from the turning transmission case 13 and the straight forward output shaft 30 that projects forward from the lower front of the straight mission case 17. The transmission case 13 for turning includes a hydraulic stepless transmission (HST) 701 for turning that appropriately changes rotational power from the engine 5, and rotation of the output from the hydraulic stepless transmission 701 to the left and right traveling crawlers 3 ( A differential gear mechanism 702 for transmitting to the sprocket 62) and a pair of left and right planetary gear mechanisms 703 for combining the rotational power from the differential gear mechanism 702 and the rotational power from the straight transmission case 17 are provided.

  The hydraulic continuously variable transmission 701 has a pair of hydraulic pump units 704 and hydraulic motor units 705 arranged in parallel, and the power transmitted to the pump shaft 706 causes the hydraulic pump units 704 to the hydraulic motor units 705. Hydraulic oil is fed appropriately. In addition, a charge pump 707 for supplying hydraulic oil to the hydraulic pump 704 and the hydraulic motor 705 is attached to the pump shaft 706. The hydraulic stepless transmission mechanism 701 for turning changes and adjusts the inclination angle of the pump swash plate 708 in the hydraulic pump unit 704 to change the discharge direction and discharge amount of hydraulic fluid to the hydraulic motor unit 705, thereby achieving hydraulic pressure. The rotational direction and rotational speed of the motor shaft 709 protruding from the motor 705 are arbitrarily adjusted.

  The turning transmission case 13 arranges the turning input counter shaft 712 in parallel with the pump shaft 706 of the hydraulic pump unit 704, and the turning input gear 713 is fitted on the turning input counter shaft 712 so that relative rotation is not possible. ing. A turning relay shaft 714 is disposed parallel to the turning input counter shaft 712 and the pump shaft 706 between the turning input counter shaft 712 and the pump shaft 706, and the turning is always meshed with the turning input gear 713. The relay gear 715 is fitted to the turning relay shaft 714 so as not to be rotatable relative to the turning relay shaft 714. The pump input gear 710 constantly meshed with the turning relay gear 715 is fitted on the pump shaft 706 so as to be non-relatively rotatable, and the rotational power from the engine 5 transmitted to the turning input counter shaft 712 turns It is transmitted to the pump shaft 706 via the relay shaft 714.

  A differential gear mechanism 702 is constituted by a bevel gear mechanism in which a pair of left and right side gears 717 are engaged on both sides of a pinion gear 716 which is fitted to the rear end of the motor shaft 709 so as not to relatively rotate in the turning transmission case 13. There is. Further, the differential gear mechanism 702 extends in the left and right directions a pair of left and right turning output shafts 718 in which the side gear 717 is fitted at one end so as not to allow relative rotation. At the other end of each of the pair of left and right turning output shafts 718, a turning output gear 719 for transmitting power to the pair of left and right planetary gear mechanisms 703 is fitted in a relatively non-rotatable manner.

  The rotational power (pivotal rotational power) from the hydraulic motor unit 705 output from the motor shaft 709 is divided into forward and reverse rotational power by the differential gear mechanism 702, and left and right through the pair of left and right pivoting output shafts 718 It is transmitted to the pair of planetary gear mechanisms 703. That is, in the differential gear mechanism 702, it is transmitted to the left planetary gear mechanism 703 as reverse rotation power through the left turning output shaft 718 fitted with the left side gear 717, while the right side gear 717 is fitted. The power is transmitted to the right planetary gear mechanism 703 as forward rotational power via the right turn output shaft 718.

  In the turning transmission case 13, a brake mechanism 751 interlocked with the operation of the brake pedal 35 is provided on the rectilinear input counter shaft 508 to which the rotational power from the rectilinear transmission case 17 is transmitted. Then, the rectilinear input gear 720 is fitted on the front end of the rectilinear input counter shaft 508 so as not to be relatively rotatable. In addition, the relay shaft 721 for straight movement is disposed in parallel with the input counter shaft 508 for straight movement, and the relay gear 722 for straight movement, which is always meshed with the input gear 720 for straight movement, can not rotate relative to the relay shaft 721 for straight movement. I'm fit.

  A bevel gear mechanism in which a ring gear 724 is meshed with a pinion gear 723 which is fitted to the rear end of the relay shaft 721 for linear movement in a relatively non-rotatable manner is provided, and the ring gear 724 can not relatively rotate the output shaft 725 for linear movement It is made to fit in. Both ends of the straight output shaft 725 are respectively connected to the pair of left and right planetary gear mechanisms 703. The rotational power (linear rotational power) from the transmission case 17 for linear movement input to the input counter shaft 508 for linear movement is transmitted to the pair of left and right planetary gear mechanisms 703 via the output shaft 725 for linear movement. Further, the braking mechanism 751 operates in response to the operation of the brake pedal 35 to attenuate or stop the rotational power of the straight output shaft 725.

  The left and right planetary gear mechanisms 703 rotate one sun gear 726, a plurality of planet gears 727 meshing with the sun gear 726, a ring gear 728 meshing with the turning output gear 719, and a plurality of planet gears 727 on the same circumference. Each of the carriers 729 to be arranged is provided. Carriers 729 of the left and right planetary gear mechanisms 703 are disposed opposite to each other at appropriate intervals on the same axis. The left and right sun gears 726 are fixed to both ends of a straight output shaft 725 on which a ring gear 724 is fitted in the middle.

  The left and right ring gears 728 are rotatably fitted on the straight output shaft 725, and the outer teeth on the outer peripheral surface thereof are meshed with the left and right swing output gears 719 to be connected to the swing output shaft 718 ing. A carrier 729 fixed to the ring gear 728 rotatably supports the planetary gear 727. The left and right carriers 729 are rotatably fitted on the left and right differential output shafts 730. Further, the left and right output transmission gears 731 integrally rotating with the left and right planetary gears 727 mesh with the left and right differential input gears 732 that are non-rotatably fitted to the left and right differential output shafts 730. doing. Left and right differential output shafts 730 are connected to left and right relay shafts 735 via relay gears 733 and 734, and left and right relay shafts 735 are connected to left and right axles 16 via final gears 736 and 737. ing.

  The left and right planetary gear mechanisms 703 receive rotation power from the straight transmission case 17 via the straight relay shaft 721 and the straight output shaft 725 to rotate the sun gear 726 at the same rotation speed in the same direction. . That is, the left and right sun gears 726 receive rotational power from the transmission case 17 for rectilinear movement as rectilinear rotation, and transmit the rotational power to the differential output shaft 730 via the planetary gear 727 and the output side conductive gear 731. Accordingly, the rotational power transmitted from the straight transmission case 17 to the left and right planetary gear mechanisms 703 is transmitted from the left and right axles 16 to the respective drive sprockets 62 at the same rotational speed in the same direction. The traveling body 1 is moved straight (forward, backward) by driving at the same rotational speed in the direction.

  On the other hand, the left and right planetary gear mechanisms 703 receive rotational power from the hydraulic motor unit 705 via the differential gear mechanism 702 and the turning output shaft 718, and rotate the ring gears 728 in the same rotational speed and in opposite directions. Rotate. That is, the left and right ring gears 728 receive rotational power from the hydraulic motor unit 705 as rotational rotation, cause the carrier 729 to overlap rotational rotation with straight rotation from the sun gear 726, and rotate the planetary gear 727 and the output side conductive gear 731. . Thereby, the rotational power obtained by adding the turning rotation to the straight-ahead rotation is transmitted to one of the left and right differential output shafts 730 via the planetary gear 727 and the output side conductive gear 731, and the left and right differential output shafts 730 are transmitted. To the other, rotational power obtained by subtracting the turning rotation to the straight-ahead rotation is transmitted via the planetary gear 727 and the output-side conductive gear 731.

  The shift output from the straight input counter shaft 508 and the motor shaft 709 is transmitted to the drive sprockets 62 of the left and right traveling crawlers 3 via the left and right planetary gear mechanisms 703, and the vehicle speed of the traveling body 2 (traveling speed And the direction of travel are determined. In other words, when the hydraulic motor unit 705 of the hydraulic continuously variable transmission 701 is stopped and the left and right ring gears 728 are fixed stationary, the rotational power from the linear transmission case 17 is input to the linear input counter shaft 508 The rotation of the rectilinear input counter shaft 508 is transmitted to the left and right sun gears 71 at the same number of revolutions, and the left and right traveling crawlers 3 are driven at the same number of revolutions in the same direction, and the traveling machine body 2 travels rectilinearly.

  Conversely, when the hydraulic motor unit 705 of the hydraulic continuously variable transmission 701 is driven in a state where the rotation of the straight transmission case 17 by the straight output shaft 30 is stopped and the left and right sun gears 71 are stationary fixed, the motor shaft 709 The left ring gear 728 rotates in the positive direction (reverse rotation) and the right ring gear 728 rotates in the reverse direction (forward rotation). As a result, one of the drive sprockets 62 of the left and right traveling crawlers 3 is forwardly rotated, and the other is backwardly rotated, and the traveling airframe 2 is turned in place (a signal turning spin turn).

  The left and right traveling crawlers 3 are driven by driving the left and right ring gears 728 by the turning rotation of the hydraulic motor portion 705 of the hydraulic continuously variable transmission 701 while driving the left and right sun gears 726 by the straight rotation from the transmission case 17 for straight traveling. The traveling airframe 2 turns to the left or right (U-turn) with a turning radius larger than the turning radius while moving forward or backward. The turning radius at this time is determined according to the speed difference between the left and right traveling crawlers 3.

  Next, a switching structure (three forward rotation steps and one reverse rotation step) of the drive speed of the PTO shaft 25 executed via the PTO transmission mechanism 505 will be described. A PTO transmission mechanism 505 for transmitting the motive power from the engine 5 to the PTO shaft 25 is disposed in the straight transmission case 17. In this case, a PTO input shaft 591 extending coaxially with the main transmission input shaft 511 is connected to the rear end side of the main transmission input shaft 511 via a PTO hydraulic clutch 590 for power transmission / reception. Further, in the transmission case 17 for rectilinear advance, a PTO transmission shaft 592, a PTO counter shaft 593 and a PTO shaft 25 extending in parallel with the PTO input shaft 591 are disposed. The PTO shaft 25 projects rearward from the rear surface of the straight transmission case 17.

  When the PTO clutch switch 53 is operated for power connection, the PTO hydraulic clutch 590 is in a power connection state, and the main shift input shaft 511 and the PTO input shaft 591 are connected so as not to allow relative rotation. As a result, rotational power is transmitted from the main shift input shaft 511 to the PTO input shaft 591.

  The PTO input shaft 591 is provided with a medium speed input gear 597, a low speed input gear 595, a high speed input gear 596, and a reverse shift gear 598 in this order from the front side. The medium speed input gear 597, the low speed input gear 595, and the high speed input gear 596 are fitted on the PTO input shaft 591 such that relative rotation is not possible. The reverse shift gear 598 is spline-fit to the PTO input shaft 591 so as to be non-relatively rotatable and axially slidable.

  On the other hand, the PTO transmission shaft 592 is rotatably fitted with the PTO medium speed gear 601 meshing with the medium speed input gear 597, the PTO low speed gear 599 meshing with the low speed input gear 595, and the PTO high speed gear 600 meshing with the high speed input gear 596. doing. A pair of front and rear PTO shift shifters 602 and 603 is spline-fitted to the PTO shift shaft 592 so as to be non-relatively rotatable and to be slidable in the axial direction. The first PTO shift shifter 602 is disposed between the PTO medium speed gear 601 and the PTO low speed gear 599. The second PTO shift shifter 603 is disposed on the rear end side relative to the PTO high speed gear 600. The pair of front and rear PTO shift shifters 602 and 603 are configured to slide in the axial direction in conjunction with the operation of the PTO shift lever 46. PTO transmission gear 604 is fixed between PTO low speed gear 599 and PTO high speed gear 600 of PTO transmission shaft 592.

  The PTO counter shaft 593 includes the PTO counter gear 605 meshing with the PTO transmission gear 604, the PTO relay gear 606 meshing with the PTO output gear 608 fitted non-rotatably to the PTO shaft 25, and the PTO reverse gear 607 Impossible to fit. By turning on the sub PTO lever 48 while the PTO gear shift lever 46 is in neutral operation, the reverse shift gear 598 slides, and the reverse shift gear 598 and the PTO reverse gear 607 of the PTO counter shaft 593 are engaged. ing.

  When the PTO shift lever 46 is shifted, the pair of front and rear PTO shift shifters 602 and 603 slide along the PTO shift shaft 592, and the PTO low speed gear 595, the PTO medium speed gear 597, and the PTO high speed gear 596 are PTO shift shafts. It is alternatively connected to 592. As a result, low-speed to high-speed PTO transmission output is transmitted from PTO transmission shaft 592 to PTO counter shaft 593 through PTO transmission gear 604 and PTO counter gear 605, and PTO relay gear 606 and PTO output gear 608 are further reduced. It is transmitted to the PTO shaft 25 via the same.

  When the sub PTO lever 48 is turned on, the reverse shift gear 598 meshes with the PTO reverse gear 607, and the rotational power of the PTO input shaft 591 is transmitted to the PTO counter shaft 593 via the reverse shift gear 598 and the PTO reverse gear 607. Then, the reverse PTO gear shift output is transmitted from the PTO counter shaft 593 to the PTO shaft 25 via the PTO relay gear 606 and the PTO output gear 608.

  Next, the hydraulic circuit 620 structure of the tractor 1 will be described with reference to FIG. The hydraulic circuit 620 of the tractor 1 includes a working machine hydraulic pump 481 and a traveling hydraulic pump 482 which are driven by the rotational power of the engine 5. In the embodiment, the straight transmission case 17 is used as a hydraulic oil tank, and the hydraulic oil (lubricating oil) in the straight transmission case 17 is coupled to the working machine via the two oil filters (suction filters) 656. The hydraulic pump 481 and the traveling hydraulic pump 482 are supplied. The traveling hydraulic pump 482 is connected via an oil filter (line filter) 487 to a closed loop oil path 623 connecting the hydraulic pump 521 and the hydraulic motor 522 in the hydraulic mechanical type continuously variable transmission 500 for going straight. While the engine 5 is operating, the hydraulic oil from the traveling hydraulic pump 482 is constantly replenished in the closed loop oil passage 623.

  The traveling hydraulic pump 482 also includes a main transmission hydraulic pressure switching valve 624 for the main transmission hydraulic cylinder 524 of the hydraulic mechanical continuously variable transmission 500 and an PTO clutch for the PTO hydraulic clutch 590 via an oil filter (line filter) 487. It is connected to a solenoid valve 627 and a switching valve 628 actuated thereby. Further, the traveling hydraulic pump 482 includes a forward low speed clutch solenoid valve 632, which operates the forward low speed hydraulic clutch 537, a forward high speed clutch solenoid valve 633, which operates the forward high speed hydraulic clutch 539, and a reverse clutch which operates the reverse hydraulic clutch 541. A solenoid valve 634 is connected to a master control solenoid valve 635 for controlling the supply of hydraulic fluid to the clutch solenoid valves 632 to 634.

  In addition, the hydraulic lift cylinders in the hydraulic lift mechanism 22 include a plurality of hydraulic external takeout valves 430 in which the work implement hydraulic pump 481 is stacked and disposed on the upper surface of the hydraulic lift mechanism 22 on the upper rear side of the straight transmission case 17. 117 A double acting control solenoid valve 432 for controlling the hydraulic oil supply to the lower side, a tilt control solenoid valve 647 for controlling the hydraulic oil supply to the horizontal cylinder 122 provided on the right lift rod 121, and the hydraulic pressure in the hydraulic lifting mechanism 22 The up oil pressure switching valve 648 and the down oil pressure switching valve 649 that control the hydraulic oil supply to the lower side of the lift cylinder 117, the up control solenoid valve 650 that switches the up oil pressure switching valve 648, and the down oil pressure switching valve 649 are operated. It is connected to the lowering control solenoid valve 651. The double acting valve mechanism 431 is constituted by a hydraulic circuit including the double acting control solenoid valve 432, and the raising and lowering valve mechanism 652 comprises an ascending hydraulic switching valve 648, a descending hydraulic switching valve 649, a climbing control electromagnetic valve 650 and descending. It comprises a hydraulic circuit by the control solenoid valve 651.

  When the tilt control solenoid valve 647 is switched and driven, the horizontal cylinder 122 expands and contracts, and the lower link 23 on the right side moves up and down with the lower link pin on the front side as a fulcrum. As a result, the ground working machine tilts to the left and right with respect to the traveling machine body 2 via the left and right lower links 23, and the left and right inclination angle of the ground working machine changes. By switching control of the double acting control solenoid valve 432, either a single acting type or a double acting type can be selected as a driving method of the hydraulic lift cylinder 117. That is, by switching the double acting control solenoid valve 432 according to the switching operation of the single double acting changeover switch 56, the drive system of the hydraulic lift cylinder 117 is set.

  When the hydraulic lift cylinder 117 is driven in a single-acting mode, the hydraulic lift cylinder 117 expands and contracts when the up hydraulic switching valve 648 or the down hydraulic switching valve 649 is switched to move both the lift arm 120 and the left and right lower links 23 together. Move up and down. As a result, the ground working machine moves up and down, and the elevation height position of the ground working machine changes. On the other hand, when the hydraulic lift cylinder 117 is driven by double acting, the hydraulic switch valve 648 or the descending hydraulic switch 649 is switched and simultaneously the double acting control solenoid valve 432 is switched to drive the hydraulic lift cylinder 117. Move it. As a result, the ground working machine can be moved up and down, and when the ground working machine is lowered, the ground working machine can be pressurized toward the ground, and the ground working machine can be held at the lowered position.

  Further, the hydraulic circuit 620 of the tractor 1 includes a charge pump 707 driven by the rotational power of the engine 5, and the charge pump 707 connects the hydraulic pump 704 and the hydraulic motor 705 in the hydraulic continuously variable transmission 701 for turning. It is connected to the closed loop oil passage 740. In the embodiment, the rectilinear transmission case 17 is used as a hydraulic oil tank, and the hydraulic oil in the rectilinear transmission case 17 is supplied to the charge pump 707 through the oil filter (suction filter) 743. Then, while the engine 5 is operating, the hydraulic oil from the charge pump 707 is constantly replenished in the closed loop oil passage 740 via the oil filter (line filter) 744. The hydraulic circuit 620 of the tractor 1 includes a swing hydraulic cylinder 741 for changing the pump swash plate 708 angle of the hydraulic pump 702 in the hydraulic continuously variable transmission 701 and a swing hydraulic switching valve 742 for the swing hydraulic cylinder 741.

  The hydraulic circuit 620 of the tractor 1 also includes a lubricating oil pump 518 driven by the rotational power of the engine 5 in addition to the working machine hydraulic pump 481 and the traveling hydraulic pump 482 described above. The lubricating oil pump 518 includes a PTO clutch hydraulic switching valve 641 that supplies hydraulic oil (lubricating oil) to the lubricating portion of the PTO hydraulic clutch 590, and a main transmission input shaft 511 that supports the hydraulic mechanical continuously variable transmission 500. The forward and low speed clutch hydraulic switching valve 642 that supplies the working oil (lubricating oil) to the lubricating portion of the lubricating portion and the forward moving low speed hydraulic clutch 537, and the forward that supplies the operating oil (lubricant) to the lubricating portion of the forward high speed hydraulic clutch 539 It is connected to a high-speed clutch hydraulic switching valve 643 and a reverse clutch hydraulic switching valve 644 which supplies hydraulic oil (lubricating oil) to the lubricating portion of the reverse hydraulic clutch 541. The hydraulic circuit 620 is provided with a relief valve, a flow control valve, a check valve, an oil cooler, an oil filter, and the like in addition to the above-described configuration as shown in FIG.

  As shown in FIGS. 16 to 19, the transmission case 13 for turning includes a transmission case 91 for turning that incorporates a hydraulic stepless transmission 701, and a pump shaft 706 and a motor shaft 709 of the hydraulic stepless transmission 701. It has a relay case 92 that houses the joint shaft to be connected, and an input / output case 93 provided with a gear mechanism that receives rotational power from the engine 5 and the straight transmission case 17 and outputs rotational power to the axle 16 Ru. A charge pump 707 is disposed on the front surface of the turning transmission case 91, and a turning hydraulic pressure switching valve 742 is disposed on the top surface thereof. An input / output case 93 is connected to the rear of the turning transmission case 91 via a relay case 92, and an axle case 90 is connected to both sides of the input / output case 93.

  As shown in FIGS. 16 to 19, oil filters 743 and 744 are provided in front of the turning transmission case 13. The oil filters 743 and 744 are suspended and fixed to a filter fixing bracket 459 provided at the left and right upper edges of the frame connecting member 12 a connecting the front ends of the left and right engine frames 14. Further, above the transmission case 13 for turning, a partition plate 460 is provided which is bridged to the left and right engine frames 14.

  Hydraulic pipes 450 to 456 for circulating the hydraulic oil to the turning transmission case 13 are extended from the straight transmission case 17 toward the turning transmission case 13. The hydraulic pipes 450 and 456 on the side of the straight transmission case 17 are disposed along the traveling body 2 outside the traveling body 2 (the engine frame 14 and the body frame 15). On the other hand, the hydraulic pipes 451, 452 and 455 on the turning transmission case 13 side are disposed inside the traveling body 2 and connected to the turning transmission case 13 via the filters 743 and 744 provided on the inside of the traveling body 2 There is.

  The hydraulic piping 450 is connected to the left side lower side of a rear transmission case 113, which will be described later, in the straight transmission case 17, and extends forward along the outer side of the machine frame 15 to the axle case 90 rear position. The hydraulic piping 451 is connected to the oil filter 743 and extends rearward along the inside of the engine frame 14 so as to straddle the turning transmission case 13 to a rear position of the axle case 90. The hydraulic piping 451 protrudes from the through hole 461 provided at the rear position of the axle case 90 in the engine frame 14 to the outside of the engine frame 14 and is connected to the hydraulic piping 450.

  The hydraulic piping 452 connects the oil filters 743 and 744 arranged inside the engine frame 14 and the charge pump 707, and the hydraulic piping 453 connected to the oil filter 744 bypasses the outside of the engine frame 14. , And the transmission case 91 for turning. The right engine frame 14 has through holes 462 and 463 at the side position of the oil filter 744 and at the side position of the transmission case 91 for turning. Further, the support bracket 81 is provided with a through hole 464 by a long hole at a position on the front end side of the support bracket 81 and overlapping with the through hole 463 of the right engine frame 14. One end (front end) of the hydraulic piping 453 is connected to the oil filter 744 inside the engine frame 14 through the through hole 462 of the engine frame 14. Further, the other end (rear end) of the hydraulic piping 453 is connected to the turning transmission case 91 inside the engine frame 14 through the through holes 463 and 464 of the engine frame 14 and the support bracket 81 respectively.

  The hydraulic piping 454 connected to the turning transmission case 91 bypasses the outside of the engine frame 14 and is connected to the hydraulic piping 455. The right engine frame 14 is provided with through holes 465 and 466 at the side position of the turning transmission case 91 and at the side position of the relay case 92. In the right engine frame 14, a through hole 465 is provided between the through holes 462 and 463 and on the front side of the support bracket 81, and the through hole 466 is a rear side of the through hole 463 and the front end of the support bracket 81 It is provided at the upper position. One end (front end) of the hydraulic piping 455 is connected to the turning transmission case 91 inside the engine frame 14 through the through hole 465 of the engine frame 14. Further, the other end (rear end) of the hydraulic piping 455 is connected to the hydraulic piping 455 inside the engine frame 14 through the through hole 466 of the engine frame 14.

  The hydraulic piping 455 is disposed along the inside of the engine frame 14 so as to straddle the upper part of the turning transmission case 13 from the relay case 92 to the rear position of the input / output case 93 and at the rear position of the input / output case 93 in the engine frame 14 It projects to the outside of the engine frame 14 from the provided through hole 467 and is connected to the hydraulic piping 456. The hydraulic piping 456 extends rearward along the outer side of the machine body frame 15 and is connected to a rear housing 74 connected to the side surface of the straight transmission case 17 (the right side surface of the rear transmission case 113 described later).

  In addition, after hydraulic pipes 457 and 458 connected to the oil cooler 274 are extended toward the transmission case 17 for going straight along the outside of the engine frame 14, under the body frame 15 near the connecting position with the body frame 15. It is extended toward the inside of the airframe 15 so as to get under the edge. The hydraulic pipes 457 and 458 extend rearward along the inside of the machine frame 15 and are connected to the straight transmission case 17.

  A rear case (input / output case) 93 in which the turning transmission case 13 incorporates a gear mechanism for outputting power to the left and right traveling parts (crollers) 3 and a front case (turning) in which the second continuously variable transmission 701 is installed And a transmission case 91). A partition plate 460 installed on the traveling body 2 (engine frame 14) is provided above the turning transmission case 13 and at a connection position of the front case 91 and the rear case 93. The hydraulic pipes 451 and 455 are fixed in the middle by the partition plate 460, and the filters 743 and 744 are suspended and supported by the traveling body 2 (engine frame 14) in front of the turning transmission case 13. A relay case 92 incorporating a relay shaft is provided between the transmission case 91 for turning and the input / output case 93, and the partition plate 460 is provided on the front side of the boundary position between the relay case 92 and the input / output case 93. Be

  Further, as shown in FIG. 18, the power transmission shaft case 31 is suspended and supported by the support beam frame 236 via the shaft case support member 31a. As a result, the power transmission shaft case 31 is supported by the traveling machine body 2 to which the turning transmission case 13 and the straight transmission case 17 are fixed. Therefore, the power transmission shaft case 31 is supported by the same vibration system, and the occurrence of breakage or failure due to mechanical vibration can be prevented. As shown in FIG. 18, the power transmission shaft case 31 may be supported by the beam frame 68 connected to the track frame 61 via the shaft case support member 31b.

  As shown in FIGS. 16-19, support brackets 81 for supporting a working machine (front dozer) 80 mounted on the front of the traveling machine 2 are fixed to the left and right side surfaces of the traveling machine 2 (engine frame 14). A pair of left and right axle cases 90 connected to both sides of the rear case (input / output case) 93 of the turning transmission case 13 is connected to a support bracket 81 which is a pair of left and right. The hydraulic pipes 451 and 455 are disposed inside the traveling body 2 (engine frame 14) at a position overlapping the support bracket in the front-rear direction. A lower frame 67 supporting the front of the track frame 61 of the traveling crawler 3 is suspended and supported on the lower side of the traveling body 2 (the engine frame 14) and is connected to the support bracket 81.

  A hydraulic pipe 89a for supplying a portion of the hydraulic oil in the transmission case 17 for linear movement to the working machine (front dozer) 80 is provided, and a pipe connecting member 89 for connecting the hydraulic pipe 89a and the hydraulic pipe 89b; A work machine valve mechanism 89 c that switches the hydraulic oil from the 89 b to the work machine (front dozer) 80 is fixed to one of the left and right support brackets 81 (in the embodiment, the right support bracket 81). The hydraulic pipe 89b is disposed on the outer side of the traveling body 2 along the traveling body 2 toward the rear of the support bracket 81, and is connected to the hydraulic circuit of the hydraulic outcoupling mechanism 430 disposed above the straight transmission case 17. Be done.

  Next, the structure of the transmission case 17 for going straight and the mounting structure of each part will be described with reference to FIGS. The straight transmission case 17 has a front transmission case 112 having a main transmission input shaft 28 and the like, a rear transmission case 113 connected to the rear housing 74, and a front side of the rear transmission case 113 behind the front transmission case 112. And an intermediate case 114 for connecting the two. Rear end portions of the left and right airframe frames 15 are connected to the left and right side surfaces of the intermediate case 114 via the left and right upper and lower airframe connecting shaft bodies 115 and 116. That is, the rear ends of the left and right airframe frames 15 are connected to the left and right side surfaces of the intermediate case 114 by the two upper airframe connection shafts 115 and the two lower airframe connection shafts 116. The straight transmission case 17 is integrally connected to form a rear portion of the traveling airframe 2, and a front transmission case 112 or a power transmission shaft 29 is disposed between the left and right airframe frames 15. The transmission case 112 and the like are configured to be protected. Left and right rear housings 74 are attached to the left and right sides of the rear transmission case 113 so as to protrude outward. In the embodiment, the intermediate case 114 and the rear transmission case 113 are made of high rigidity cast iron, while the front transmission case 112 is made of lightweight aluminum die cast with good workability.

  According to the above configuration, since the transmission case 17 for rectilinear advance is divided into three parts, the front transmission case 112, the intermediate case 114, and the rear case 113, each case 112 to 114 has a shaft, a gear, etc. After the parts are incorporated in advance, the three components of the front transmission case 112, the intermediate case 114 and the rear transmission case 113 can be assembled. Therefore, the linear transmission case 17 can be assembled accurately and efficiently.

  In addition, an intermediate case of high rigidity structure connecting the front transmission case 112 and the rear transmission case 113 to the left and right rear housings 74 attached to the left and right sides of the rear transmission case 113 and connecting the front transmission case 112 and the rear transmission case 113 Since the 114 is connected, for example, with the intermediate case 114 and the rear shift case 113 attached to the machine frame 15, only the front shift case 112 is removed, and the hydraulic continuously variable transmission 500 etc. is installed inside. It is possible to execute maintenance or repair work such as replacement of shafts and gears in the internal gear shift case 112. Therefore, the frequency of disassembling work for removing the entire straight transmission case 17 from the tractor 1 can be remarkably reduced, and the workability at the time of maintenance and repair can be improved.

  Furthermore, the middle case 114 and the rear shift case 113 are made of cast iron while the front shift case 112 is made of aluminum die-cast, so the middle case 114 connected to the machine frame 15 and the left and right rear housings 74 The rear shift case 113 connected can be configured to be highly rigid as a strength member that configures the traveling body 2. In addition, it is possible to reduce the weight of the front transmission case 112 which is not a strength member. Therefore, it is possible to reduce the weight of the straight transmission case 17 as a whole while securing the rigidity of the traveling body 2 sufficiently.

  As shown in FIG. 18 to FIG. 24, the pump case 480 is disposed at the front of the right outer surface of the rear transmission case 113 in the transmission case 17 for going straight. In the pump case 480, a working machine hydraulic pump 481 and a traveling hydraulic pump 482 are accommodated. The suction side of the work machine hydraulic pump 481 and the traveling hydraulic pump 482 is connected via a filter bracket 655 to two oil filters 656 located below the pump case 480 in the front right of the rear shift case 113. ing. The two oil filters 656 are detachably attached to the filter bracket 655. A suction nozzle 657 extending to the inside of the transmission case 17 for going straight (inside the rear shift case 113) is attached to the filter bracket 655. The suction nozzle 657 in the rear transmission case 113 communicates with the two oil filters 656 via the filter bracket 655.

  The work implement and traveling hydraulic pumps 481 and 482 and the two oil filters 656 are located forward of the rear housing 74 (in the embodiment, the right rear housing 74) projecting outward from the rear transmission case 113 in the left and right direction, , Located below the control seat 8 on the traveling body 2 (see FIG. 8). Thus, the working machine and traveling hydraulic pumps 481 and 482 and the two oil filters 656 are disposed apart from the control seat 8 enclosed by the cabin 7.

  A gear case 486 housing a spur gear mechanism 485 is projected outward in the left and right direction above the two oil filters 656 on the right outer surface front of the rear transmission case 113. A pump case 480 is attached to the front side of the gear case 486. A pump drive shaft 483 protruding from the working machine and traveling hydraulic pumps 481 and 482 in the pump case 480 extends into the gear case 486. In the gear case 486, a pump drive gear 484 fixed to the pump drive shaft 483 is connected to the spur gear mechanism 485 so that power can be transmitted (see FIG. 14).

  As shown in FIGS. 18 to 24, a double acting valve mechanism 431 is provided on the left and right other sides (the left outer surface side of the rear shift case 113) of the transmission case 17 for going straight located opposite to the pump case 480 etc. ing. The double acting valve mechanism 431 is located forward of the rear housing 74 (in the embodiment, the right rear housing 74) projecting leftward and rightward from the rear transmission case 113 and below the steering seat 8 on the traveling body 2 doing. That is, the pump case 480 is provided at a position distributed to the left and right with the straight transmission case 17 (rear shift case 113) interposed therebetween.

  The double acting valve mechanism 431 is disposed at a position facing the pump case 480 with the straight transmission case 17 interposed therebetween, and is connected to the working machine hydraulic pump 481 in the pump case 480 by hydraulic piping. Therefore, the hydraulic piping 745 connecting the double acting valve 431 and the working machine hydraulic pump 481 can be shorted, and not only the working efficiency in piping work can be improved, but also the piping loss in the hydraulic circuit 745 can be reduced.

  The double acting valve mechanism 431 is mounted on a valve support bracket 433 fixed to the front surface of the rear housing 74 connected to the rear side (the left outer surface side of the rear transmission case 113) of the straight transmission case 17. . That is, the valve support bracket 433 is bolted to the front surface of the rear housing 74 projecting to the side (left side) of the straight transmission case 17, and the double acting valve mechanism 431 is bolted to the upper surface of the valve support bracket 433. It is done. Therefore, the double acting valve mechanism 431 can be supported by the rear housing 74 with high rigidity.

  In addition, the double-acting valve mechanism 431 is disposed together with the hydraulic pumps 481 and 482 and the two oil filters 656 by effectively utilizing the front portion of the rear housing 74, that is, the portion where the work space is easily secured. This helps to make the transmission case 17 for straight ahead compact. In addition, since the hydraulic pump 481 and the double acting valve mechanism 431 are arranged at the positions distributed to the left and right with the transmission case 17 for linear movement, it is possible to shorten the hydraulic piping connecting the hydraulic pump 481 and the double acting valve mechanism 431.

  As shown in FIGS. 18 to 24, the front cover member 491 detachably fastened to the front surface of the transmission case 17 for rectilinear transmission, that is, the front surface of the front transmission case 112, includes a traveling hydraulic pump 482 as an oil pressure source and each hydraulic pressure. They form part of a hydraulic circuit 620 connecting the clutches 537, 539, 541. The clutch solenoid valves 632, 633, 634 and the master control solenoid valve 635 are disposed on the front side of the front lid member 491.

  The clutch solenoid valves 632, 633, 634 and the master control solenoid valve 635 are assembled into a unit in an oil passage block 660. An oil passage block 660 with each clutch solenoid valve 632, 633, 634 and a master control solenoid valve 635 is detachably fastened to the front side of the front lid member 491. Further, an oil filter (line filter) 487 disposed on a hydraulic oil supply path to the hydraulic mechanical continuously variable transmission 500 is fixed to the front surface of the front lid member 491.

  The transmission case 17 for straight ahead incorporates a PTO hydraulic clutch 590 for switching power transmission to the PTO transmission mechanism 505, a PTO clutch solenoid valve 627 for operating the PTO hydraulic clutch 590, and a PTO valve accommodating a switching valve 628 (PTO valve). A case 663 is provided. As shown in FIGS. 15-17, the PTO valve case 663 is disposed at a position overlapping the PTO hydraulic clutch 590 in a side view on the left outer surface of the transmission case 17 for rectilinear advance, ie, the left outer surface of the rear shift case 113. doing. As described above, a pump case 480 containing a hydraulic pump 481 for a working machine driven by the rotational power of the engine 5 and a hydraulic pump 482 for traveling is mounted on the front right outer surface of the rear transmission case 113. Therefore, the pump case 480 and the PTO valve case 663 are located on the left and right sides of the rear shift case 113.

  A PTO valve case 663 provided with PTO valves 627 and 628 is positioned on the left and right sides of the rear case 113 located forward of the rear housing 74 and opposite to the hydraulic pumps 481 and 482. The hydraulic pumps 481 and 482 and the PTO valves 627 and 628 are separately disposed on the left and right sides of the rear shift case 113, effectively utilizing a location where it is easy to secure a working space in front of the rear housing 74. The hydraulic pumps 481 and 482 and the PTO valves 627 and 628 can be arranged efficiently. Furthermore, the PTO valve case 663 is effectively disposed in the space between the straight transmission case 17 and the double-acting bubble mechanism 431, and helps to make the straight transmission case 17 compact.

  As shown in FIG. 18 to FIG. 24 etc., the hydraulic lifting mechanism 22 controls the hydraulic lift cylinders 117 on the left and right that are operated and controlled by operating the working part position dial 51 etc. The left and right lift arms 120 pivotally pivotally supporting the base end side via the lift fulcrum shaft 119 to the openable upper lid 118 provided on the side and the left and right lift arms 120 are connected to each other It has lift rods 121 on the left and right. A part of the right lift rod 121 is formed by a horizontal cylinder 122 for hydraulic pressure control, and the length of the right lift rod 121 is configured to be adjustable by extension and contraction by the horizontal cylinder 122.

  Further, the top link hinge 123 is fixed to the back side of the top lid 118, and the top link 24 is connected to the top link hinge 123 via a hinge pin. If the piston of the horizontal cylinder 122 is extended and contracted to change the length of the right lift rod 121 under the condition that the ground work machine is supported by the top link 24 and the lower links 23 on the left and right, the right and left tilt of the ground work machine It is configured to change the angle.

  Then, as shown in FIGS. 18 to 24 and the like, the lift valve mechanism 652 (rising hydraulic pressure switching valve 648 and hydraulic lowering pressure switching valve 649) and tilt control solenoid valve 647 are provided on the upper surface lid 118 installed on the upper surface of the rear transmission case 113. Is placed. Therefore, hydraulic equipment parts related to the lifting and lowering mechanism 22 provided in the rear of the straight transmission case 17 can be collectively arranged on the upper surface lid 118 and the unit can be configured, and the lifting valve mechanism 652 arranged on the upper surface side of the straight transmission case 17 Assembling and maintenance work of the switching valve 648 and the lowering hydraulic switching valve 649) and the inclination control solenoid valve 647 can be simplified easily, and the assembling ease of the straight transmission case 17 can be improved.

  The lifting mechanism 22 includes left and right lift arms 120 connecting the left and right lift cylinders 117 and the left and right lower links 23, as shown in FIGS. Then, lift fulcrum shaft 119 as an elevating fulcrum shaft is penetrated to the left and right in the rear part of upper surface lid 118, and left and right lift arm 120 base end portions are pivotally supported at left and right both ends The left and right lift arms 120 are disposed on the upper lid 118 via a lift fulcrum shaft 119 as a lift fulcrum shaft. Therefore, the elevating mechanism 22 (the elevating valve mechanism 652 and the lift arm 120) can be disposed on the upper surface side of the upper surface lid 118, and the assembly and maintenance work of the elevating mechanism 22 on the straight transmission case 17 can be simplified. Further, by supporting the lift valve mechanism 652 at the front of the top cover 118 and supporting the lift arm 120 at the rear of the top cover 118 via the lift fulcrum shaft 119, the straight transmission case 17 (rear gear change case The elevating mechanism 22 can be compactly installed on the upper surface side of 113).

  As shown in FIGS. 18 to 24, a valve plate 653 for hydraulically connecting the lift cylinder 117 via hydraulic piping, and a hydraulic proportional valve (a lift control solenoid valve 650 and a drop control solenoid valve 651) as the lift valve mechanism 652 Have. Then, the valve plate 653 is placed on the front upper surface of the upper lid 118, and the lift valve mechanism 652 (the lift control solenoid valve 650 and the drop control solenoid valve 651 as hydraulic proportional valves) is placed on the top surface of the valve plate 653. ing. Further, a tilt control solenoid valve 647 is disposed at the rear of the top surface of the top lid 118. More specifically, a tilt control solenoid valve 647 is disposed on the upper surface of the upper surface lid 118 between the lift valve mechanism 652 on the upper surface front of the upper surface lid 118 and the lift fulcrum shaft 119.

  Therefore, elevating valve mechanism 652 (rising hydraulic switching valve 648 and lowering hydraulic switching valve 649, lifting control solenoid valve 650 and lowering control solenoid valve 651) is assembled to the upper surface lid 118 via the valve plate 653 constituting the hydraulic circuit. In the state, the valve plate 653 can be attached to and detached from the upper surface lid 118, while the upper surface lid 118 can be attached to and detached from the upper surface of the straight transmission case 17 with the valve plate 653 assembled to the upper surface lid 118. Assembling and maintenance workability of the lift valve mechanism 652 and the tilt control solenoid valve 647 can be simplified. Further, the inclination control electromagnetic valve 647 can be disposed on the upper surface side closer to the horizontal cylinder 122 among the upper surface side of the upper surface lid 118, and hydraulic piping work or maintenance operation of the horizontal cylinder 122 and the inclination control electromagnetic valve 647 is simplified. Can be

  As shown in FIG. 1 to FIG. 6, FIG. 10, FIG. 19, etc., the hydraulic pressure as a hydraulic external takeout mechanism for supplying hydraulic fluid to a hydraulic drive work machine (front loader work machine etc.) detachably mounted on the traveling machine 2 An external outlet valve 430 is provided. Then, the hydraulic pressure external takeout valve 430 is disposed above the lift fulcrum shaft 119 installation portion of the upper surface lid 118. Therefore, the hydraulic device component (hydraulic external extraction valve 430) related to the lifting mechanism 22 provided behind the linear transmission case 17 can be collectively arranged on the upper surface lid 118, and the unit can be configured. Assembling and maintenance work of the valve 430 can be simplified easily, and the assembling ease of the rectilinear transmission case 17 can be improved.

  Then, the hydraulic pressure external takeout valve 430 is mounted on the upper surface of the upper surface lid 118 and on the rear side of the inclination control solenoid valve 647. Therefore, with the hydraulic external takeout valve 430 and the inclination control solenoid valve 647 assembled to the upper face cover 118, the upper face cover 118 can be attached to and detached from the transmission case 17 for rectilinear movement. The hydraulic external takeoff valve 430 and the inclination control electromagnetic valve Assembling and maintenance of the 647 can be simplified. By arranging the hydraulic pressure external extraction valve 430 at a position where hydraulic piping is easy at the rearmost part of the top surface of the straight transmission case 17, the handling workability of the hydraulic pressure external extraction valve 430 can be improved.

  As shown in FIGS. 18 to 24, the lifting mechanism 22 includes a lifting cylinder 117 for lifting the link mechanism 111, a lifting valve mechanism 652 for supplying hydraulic fluid to the lifting cylinder 117 to lift the cylinder rod 125, and a lifting cylinder 117. And a double acting valve mechanism 431 which lowers the cylinder rod 125 by supplying hydraulic oil to the valve. A lift valve mechanism 652 is disposed on the rear upper surface (in the embodiment, the upper surface of the upper surface lid 118) of the transmission case 17 for rectilinear movement, and one side of the transmission case 17 for rectilinear movement (in the embodiment, left side of the rear shift case 113). The double acting valve mechanism 431 is disposed on the

  Therefore, when the double acting valve mechanism 431 is additionally attached as the raising and lowering mechanism 22, each component of the raising and lowering mechanism 22 is disposed at the rear of the linear movement transmission case 17, each hydraulic pressure connected with the double acting valve mechanism 431 Not only can the pipes 746 to 749 be shortened, but the complexity of the installation work of the pipes can be eliminated. Further, in the raising and lowering mechanism 22, components capable of single action operation other than the double acting valve mechanism 431 are collectively installed on the upper surface lid 118 of the straight transmission case 17, while double acting operation is also possible. The moving valve mechanism 431 is installed on the side of the rear transmission case 113 of the transmission case 17 for going straight. Therefore, when assembling a working vehicle equipped with a mechanism based on single-acting motion of only the lifting valve mechanism 652 as the lifting mechanism 22 and a working vehicle equipped with a mechanism also capable of double-acting motion provided with the double acting valve mechanism 431 In addition, errors in each assembly operation can be prevented.

  Further, as shown in FIG. 18 to FIG. 24, the elevation mechanism 22 controls the horizontal cylinder 122 to change the left and right inclination angle of the work machine supported by the link mechanism 111, and the inclination control solenoid valve to operate the horizontal cylinder 122 (horizontal control And a valve 647. Then, the inclination control solenoid valve 647 is disposed at the rear of the lift valve mechanism 652 on the rear upper surface (in the embodiment, the upper surface of the upper surface lid 118) of the transmission case 17 for rectilinear movement. Further, a hydraulic pressure external takeout valve 430 is disposed behind the tilt control solenoid valve 647 to switch the hydraulic oil into and out of the hydraulically driven working machine detachably mounted on the traveling machine body 2. Then, the hydraulic pressure output valve 430 and the inclination control solenoid valve 647 are connected to the double acting valve mechanism 431 by hydraulic pipes 747 and 748, respectively.

  As shown in FIGS. 19 to 24, a rear housing (frame rear connection body) 74 connected to the rear portion of the track frame 61 having the crawlers 3 is connected to the left and right of the straight transmission case 17. At this time, while supporting the rear of the cabin (steering unit) 7 on the side surface of the rear housing 74, the double acting valve mechanism 431 is supported on the front surface of the rear housing 74. Further, a rear beam 72 connected to the rear end of the track frame 61 is connected to the lower surface of the rear housing 74. Therefore, the double acting valve mechanism 431 is supported by the straight transmission case 17 which is a part of the traveling body 2 and which is a high rigidity component together with the cabin 7. In addition, since the rear housing 74 is a member connected to the track frame 61, the double acting valve mechanism 431 is supported in a stable state.

  The rear housing 74 has a valve support bracket 433 bolted to its front side, a rear support 97 bolted to its side, and a rear beam 72 bolted to its lower surface. The double acting valve mechanism 431 is mounted and fixed on the upper surface of the valve support bracket 433 fixed in a cantilevered manner to the rear housing 74 by bolt fastening. Also, the tank frame 18 and the anti-vibration rubber body 99 are installed on the upper surface of the rear support base 97 fixed in a cantilevered manner to the rear housing 74. The fuel tank 11 and the battery 817 are fixed to the tank frame 18, and the cabin frame 300 is connected to the vibration-proof rubber body 99, and the rear support base 97 not only the rear portion of the cabin 7 but also the fuel tank 11 and A battery 817 is supported.

  The double acting valve mechanism 431 is also connected to the rear housing 74 by a hydraulic pipe 749. As a result, the hydraulic oil from the double acting valve mechanism 431 is returned to the transmission case 17 for linear movement, which is a hydraulic oil tank, through the rear housing 74. Therefore, by supporting the double acting valve mechanism 431 on the rear housing 74 via the valve support bracket 743, it can be configured together with the rear housing 74 as a unit for adding a double acting function, so that the assembly ease can be improved.

  The configuration of each part in the present invention is not limited to the illustrated embodiment, and various changes can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 2 running body 3 running crawler 4 wheel 5 diesel engine 8 steering seat 13 turning transmission case 17 forward running transmission case 500 hydraulic mechanical transmission 642 forward low speed clutch hydraulic switching valve 643 forward high speed clutch hydraulic switching valve 644 reverse clutch hydraulic switching valve 701 Hydraulic continuously variable transmission (HST)

Claims (6)

An engine mounted on a traveling body, a transmission case for rectilinear advance having a first linear transmission having a first continuously variable transmission disposed therein, and a turning transmission case having a second transmission having a second continuously variable transmission disposed thereon. A work vehicle comprising: an output of the straight traveling transmission path and an output of the turning transmission path to drive the left and right traveling parts.
A first hydraulic pipe for circulating hydraulic oil to the second continuously variable transmission is extended from the straight transmission case to the turning transmission case.
The first hydraulic piping is disposed along the traveling body outside the traveling machine body on the side of the straight transmission case, and disposed inside the traveling body on the turning transmission case side, and the traveling body A working vehicle connected to the turning transmission case via a filter provided inside. The turning transmission case has a configuration in which a rear case for incorporating a gear mechanism for outputting power to the left and right traveling parts and a front case for incorporating the second continuously variable transmission are connected. ,
A partition plate installed on the traveling body is provided above the turning transmission case and at a connection position of the front case and the rear case, and the middle of the first hydraulic piping is fixed by the partition plate Yes,
The work vehicle according to claim 1, wherein the filter is suspended and supported by the traveling machine body in front of the turning transmission case. Support bracket for supporting the work machine is mounted on the traveling machine body forward is fixed to the left and right sides of the traveling machine body,
A pair of left and right axle cases connected to both sides of a rear case of the turning transmission case are respectively connected to the support brackets as a left and right pair,
The work vehicle according to claim 1 or 2, wherein the first hydraulic piping is disposed inside the traveling machine body at a position overlapping the support bracket in the front-rear direction. The traveling unit is a traveling crawler, and
The work vehicle according to claim 3, characterized in that a lower frame supporting the track frame front of the traveling crawler is suspended and supported on the lower side of the traveling body and is connected to the support bracket. The second hydraulic pipe for supplying a part of the hydraulic oil in the transmission case for straight movement to the working machine, and the third hydraulic pipe connected to a working machine valve mechanism for switching the hydraulic oil into and out of the working machine Yes,
The pipe connection member for connecting the second hydraulic pipe and the third hydraulic pipe, and the work machine valve mechanism are fixed to one of the left and right support brackets. Work vehicle described in. The third hydraulic pipe is disposed on the outer side of the traveling body along the traveling body and rearward of the support bracket, and is detachably mounted on the traveling body disposed above the straight transmission case. The work vehicle according to claim 5, wherein the work vehicle is connected to a hydraulic circuit of a hydraulic external takeout mechanism that supplies hydraulic fluid to a hydraulic drive working machine.

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