JP2007139126A - Work vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily perform installation or removal work of an operation mechanism such as a shift operation body and a shift link mechanism of a hydraulic continuously variable transmission from the outside of a main machine housing in a state of incorporating the hydraulic continuously variable transmission into the main machine housing. <P>SOLUTION: This work vehicle has the hydraulic continuously variable transmission 25 for shifting motive power from an engine, a transmission case for transmitting shift output from the hydraulic continuously variable transmission via a shift output gear to a traveling part, and a shift pedal connected via a shift link mechanism 300 to a trunnion arm 35 for shift operation of the hydraulic continuously variable transmission. The hydraulic continuously variable transmission and the trunnion arm are arranged in the main machine housing 10 of a traveling machine body, and one end side of the shift operation body is detachably fixed to the trunnion arm, and the other end side of the shift operation body is projected outside from a shift operation hole 424 of the main machine housing, and the shift link mechanism is connected to the other end side of the shift operation body. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a work vehicle such as a tractor used for agricultural work or a wheel loader used for civil engineering work, and more particularly to a work vehicle in which a hydraulic continuously variable transmission is provided in a clutch housing or the like. .

  Conventionally, in general, in a working vehicle such as a tractor or a wheel loader described above, when power is transmitted to traveling parts such as left and right traveling wheels or traveling crawlers, power is transmitted from an engine mounted on a traveling machine body in the working vehicle to a transmission case. Thus, it is configured to output to the left and right traveling parts via the transmission mechanism of the transmission case.

In this case, in a conventional work vehicle, a transmission case is provided in the traveling machine body, a hydrostatic continuously variable transmission is provided in the transmission case, and power from the engine is input to the continuously variable transmission. In addition, power is transmitted from the continuously variable transmission to the traveling unit via the transmission case. In addition, a shift pedal for increasing and decelerating the forward and backward shift output of the continuously variable transmission is provided, and the shift pedal is connected to the continuously variable transmission via a link mechanism (for example, Patent Document 1). reference). It is also known to provide a neutral position adjustment mechanism for holding the trunnion shaft of the continuously variable transmission at a neutral position (see, for example, Patent Document 2).
Japanese Patent Laid-Open No. 10-44811 JP-A-11-201028

  In Japanese Patent Application Laid-Open No. 2004-133620, the prior art connects a trunnion shaft of the hydraulic continuously variable transmission to the shift pedal via a link mechanism (arm and rod), and a roller is attached to a cam plate that rotates integrally with the trunnion shaft. Since the trunnion shaft is held at the neutral position, when adjusting the neutral position of the hydraulic continuously variable transmission, it is necessary to replace the cam plate with the trunnion shaft. Further, in Patent Document 2, a locking pin provided on a trunnion cover is engaged with an engagement hole of the trunnion shaft, and the neutral position of the hydraulic continuously variable transmission is adjusted, and then linked to the shift pedal. It is necessary to connect the trunnion shaft via a mechanism. Therefore, in the techniques shown in Patent Document 1 and Patent Document 2, when the hydraulic continuously variable transmission is installed in, for example, a clutch housing, the trunnion shaft is connected to the shift pedal via a link mechanism. Thus, there is a problem that the neutral position of the hydraulic continuously variable transmission cannot be adjusted.

  An object of the present invention is to provide the shift operating body of the hydraulic continuously variable transmission from the outside of the main housing with the hydraulic continuously variable transmission built in the main housing such as a clutch housing and the like. It is an object of the present invention to provide a work vehicle in which an operation mechanism such as a shift link mechanism can be easily assembled or removed.

  To achieve the above object, a power transmission device for a work vehicle according to a first aspect of the present invention includes an engine mounted on a traveling machine body including a traveling unit, and a hydraulic continuously variable transmission that shifts power from the engine. A transmission case that transmits a shift output from the hydraulic continuously variable transmission to the traveling unit via a shift output gear, and a trunnion arm for shift operation of the hydraulic continuously variable transmission via a shift link mechanism. In a work vehicle including a shift pedal to be connected, the hydraulic continuously variable transmission and the trunnion arm are provided in the main body housing of the traveling body, and one end side of the speed change operation body can be attached to and detached from the trunnion arm. The other end side of the speed change operation body protrudes outward from the speed change operation hole of the machine housing, and the speed change link mechanism is connected to the other end side of the speed change operation body. It is intended.

  According to a second aspect of the present invention, in the power transmission device for a work vehicle according to the first aspect, the power transmission device includes a neutral adjustment body that adjusts a neutral position of the trunnion arm, and the neutral adjustment body is disposed on an outer surface of the machine housing. It is what is arranged.

  According to a third aspect of the present invention, in the power transmission device for a work vehicle according to the second aspect of the present invention, the power transmission device includes a pin spring type spring means for holding the trunnion arm in a neutral position, and the spring is provided on an outer surface of the machine housing. Means for holding the shift operation body between both ends of the spring means of the spring means so that both ends of the spring means of the spring means can contact and separate from the locking portions of the neutral adjustment body. It is comprised so that it may touch.

  According to a fourth aspect of the present invention, in the power transmission device for a work vehicle according to the third aspect, a notch hole is formed in the neutral adjustment body, the speed change operating body is passed through the notch hole, and the book The neutral adjustment body is fastened to the outer surface of the machine housing via a fulcrum bolt and an adjustment bolt.

  According to a fifth aspect of the present invention, in the power transmission device for a work vehicle according to the fourth aspect, one end side of the trunnion arm is fixed to a trunnion shaft of the hydraulic continuously variable transmission, and the other trunnion arm A nut body is fixed to the end side, the speed change operation body is formed by processing a base material having a polygonal column shape, and one end side of the speed change operation body is screwed to the nut body from the outside of the machine housing. It is configured to be operable.

  According to the first aspect of the present invention, the engine mounted on the traveling machine body including the traveling unit, the hydraulic continuously variable transmission that shifts the power from the engine, and the traveling unit via the transmission output gear. In a work vehicle comprising: a transmission case that transmits a shift output from the hydraulic continuously variable transmission; and a shift pedal that is connected to a trunnion arm for a shift operation of the hydraulic continuously variable transmission via a shift link mechanism. The hydraulic continuously variable transmission and the trunnion arm are installed in the main body housing of the traveling machine body, and one end side of the speed change operation body is detachably fixed to the trunnion arm, and the speed change operation of the main body housing is performed. Since the other end side of the speed change operating body protrudes outward from the hole and the speed change link mechanism is connected to the other end side of the speed change operation body, the hydraulic housing is connected to the machine housing. With the built-in step transmission and the trunnion arm built in, it is possible to easily perform the assembly or removal work of the speed change operation body and the speed change link mechanism, etc. The disassembly workability can be improved.

  According to the second aspect of the present invention, since the neutral adjustment body for adjusting the neutral position of the trunnion arm is provided, and the neutral adjustment body is disposed on the outer surface of the machine housing, the machine housing The neutral position of the trunnion arm can be easily adjusted by operating the neutral adjustment body outside the frame, and the assembly workability of the shift operation body and the shift link mechanism and the neutral position adjustment workability of the trunnion arm can be improved. It can be improved.

  According to a third aspect of the present invention, there is provided a pinching spring type spring means for holding the trunnion arm in a neutral position, the spring means is disposed on the outer surface of the machine housing, and the pinching spring type of the spring means is provided. The shift operation body is sandwiched by both end portions, and both end portions of the pinching spring shape of the spring means are configured to come into contact with and separable from the locking portions of the neutral adjustment body. The spring means can be compactly installed in the vicinity of the neutral adjuster. The trunnion arm can be returned to the neutral position and held by the biasing force of the spring means, and the shift pedal can be returned to the initial position and maintained.

  According to a fourth aspect of the present invention, a notch hole is formed in the neutral adjustment body, the speed change operation body is passed through the notch hole, and a fulcrum bolt and an adjustment bolt are provided on the outer surface of the machine housing. Since the neutral adjustment body is fastened, the neutral adjustment body can be rotated around the fulcrum bolt by loosening the adjustment bolt on the outer side of the machine housing. That is, the neutral position of the trunnion arm (position where the shift output is substantially zero) can be easily adjusted on the outside of the machine housing. Further, the notch hole can be formed so that the speed change operation body can come into contact, and the neutral adjustment body can be used as a stroke stopper for limiting the speed change operation of the trunnion arm.

  According to the fifth aspect of the present invention, the one end side of the trunnion arm is fixed to the trunnion shaft of the hydraulic continuously variable transmission, and the nut body is fixed to the other end side of the trunnion arm. The body is formed by processing a base material having a polygonal column shape, and is configured such that one end side of the speed change operation body can be screwed to the nut body from the outside of the machine housing. The hydraulic continuously variable transmission for connecting the shift pedal to the trunnion arm in a state where the assembly work of the machine housing and the hydraulic continuously variable transmission and the assembly work of the shift pedal and the like are completed. It is possible to assemble accessory parts for the gear shift operation system of the machine, improve maintenance workability such as adjustment of the gear shift operation system of the hydraulic continuously variable transmission, and assemble the machine housing and the gear shift pedal, etc. Disassembly work It is those that can be improved.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, drawings when an embodiment of the present invention is applied to a farm tractor as a work vehicle will be described. 1 is a side view of the tractor, FIG. 2 is a plan view of the traveling aircraft body, FIG. 3 is an enlarged plan view of the latter half of the traveling aircraft body, and FIG. 4 is an enlarged plan view of a peripheral portion of a step frame of the traveling aircraft body. 5 is a perspective view of a pedal or the like operated by an operator, FIG. 6 is a sectional side view of the mission case and the mission front case, FIG. 7 is an explanatory front view of the mission front case, and FIG. 8 is a hydraulic circuit diagram.

  As shown in FIGS. 1 and 2, the tractor 1 supports a traveling machine body 2 with a pair of left and right rear wheels 4 as well as a pair of left and right front wheels 3, and an engine 5 mounted on the front portion of the traveling machine body 2. The two rear wheels 4 and the two front wheels 3 are driven to drive forward and backward. The traveling machine body 2 has an engine frame 8 having a front bumper 6 and a front axle case 7, a clutch housing 10 having a main clutch 9 for interrupting power output from the engine 5, and a speed change of the engine 5 as appropriate. A transmission case 11 for transmitting to the rear wheels 4 and the front wheels 3, a transmission front case 12 for connecting the transmission case 11 to the clutch housing 10, and outward from the outer surface of the clutch housing 10. It comprises a pair of left and right step frames 13 that are detachably mounted so as to protrude.

  The rear end side of the engine frame 8 is connected to the left and right outer surfaces of the engine 5. The front side of the clutch housing 10 is connected to the rear side of the engine 5. The front side of the mission case 11 is connected to the rear side of the clutch housing 10 via a mission front case 12.

  The engine 5 is covered with a hood 14. A steering column 15 is erected on the upper surface of the clutch housing 10. A steering handle 16 that is steered by moving the front wheels 3 to the left and right is disposed on the upper surface side of the steering column 15. A control seat 17 is disposed on the upper surface of the mission case 11. Flat floor boards 18 are respectively provided on the upper surfaces of the pair of left and right step frames 13. Both front wheels 3 are attached to the engine frame 8 via a front axle case 7. Further, as shown in FIG. 3, both rear wheels 4 are connected to the transmission case 11 via a rear axle case 11a that is detachably mounted so as to protrude outward from the outer surface of the transmission case 11. Installed. The upper surface side of both rear wheels 4 is covered with left and right rear fenders 4a.

  On the upper surface of the transmission case 11, a hydraulic working machine lifting mechanism 20 for lifting and lowering a working machine 19 such as a tiller connected to the rear part of the traveling machine body 2 is detachably attached. Further, a PTO shaft 21 for transmitting a driving force to the work machine 19 is provided on the rear side surface of the transmission case 11 so as to protrude rearward. The work machine 19 is connected to the rear portion of the mission case 11 via a three-point link mechanism 24 including a pair of left and right lower links 22 and one top link 23. When the left and right lift arms 20a of the work implement lifting mechanism 20 are connected to the left and right lower links 22 via the lift links 20b and the work implement lift mechanism 20 is operated, the work implement 19 moves up and down. .

  A hydrostatic continuously variable transmission (HST) 25 described later is disposed on the front side surface of the mission front case 12. The hydrostatic continuously variable transmission 25 is installed in the rear part of the clutch housing 10. The rotation of the engine 5 is transmitted to the continuously variable transmission 25 via a main drive shaft 26 protruding rearward from the main clutch 9, and then the output from the continuously variable transmission 25 is transmitted by a sub transmission gear mechanism 59 described later. The gears are appropriately shifted and transmitted to the rear wheels 4 and the front wheels 3. On the other hand, the rotation of the engine 5 from the main drive shaft 26 is transmitted to a PTO output reduction gear mechanism 62, which will be described later, via a PTO transmission shaft 62a and a PTO clutch 62b, and is appropriately decelerated by the PTO output reduction gear mechanism 62. Then, it is transmitted to the PTO shaft 21.

  Next, with reference to FIG.4 and FIG.5, the structure of the control part which the operator of the control seat 17 operates is demonstrated. A clutch pedal 31 for disengaging the main clutch 9 is disposed on the left side of the control column 15 protruding upward from the floor plate 18 in front of the control seat 17. A clutch release mechanism 39 that disconnects the main clutch 9 and a clutch-containing spring 40 that maintains the clutch pedal 31 in the initial position are connected to the clutch pedal 31, and the clutch pedal 31 is maintained in the initial position by the clutch-containing spring 40. Will be. A clutch operating shaft 302 is pivotally supported on the clutch housing 10, and a release fork of the clutch disengaging mechanism 39 in the clutch housing 10 is disposed on the clutch operating shaft 302. Further, a boss 31b at the base end of the pedal arm 31a of the clutch pedal 31 is rotatably fitted to a brake operation shaft 262, which will be described later, and the clutch pedal 31 is connected to the clutch operation shaft 302 via the clutch operation link mechanism 303. (See FIG. 5). By depressing the clutch pedal 31, the main clutch 9 is disengaged. The clutch operation link mechanism 303 includes a first clutch link 305 fixed to the boss portion 31b, a second clutch link 304 fixed to the clutch operation shaft 302, and a clutch rod 306 connected to the links 304 and 305. Consists of.

  On the other hand, a single brake pedal 33 for operating the left and right rear wheel braking brake mechanism 32 and a parking brake lever 34 are arranged to the right of the steering column 15. Left and right rear wheel braking brake mechanisms 32 are connected to the brake pedal 33 via left and right brake rods 32a, and the brake mechanism 32 is activated by the operation of the brake pedal 33, and the left and right rear wheels 4 are braked. It will be. Further, the brake pedal 33 is maintained in the depressed position by the operation of the parking brake lever 34, and the braking of the rear wheel 4 is continued even if the operator lifts his / her foot from the brake pedal 33. A brake operation bearing portion 261 is integrally formed at the bottom of the clutch housing 10 by casting. A brake operation shaft 262 is rotatably supported on the brake operation bearing portion 261 (see FIG. 6). The left and right brake rods 32a are connected to the brake pedal 33 via a brake operation shaft 262 (see FIG. 5).

  Further, to the right of the steering column 15, there are a forward pedal 36 and a reverse pedal 37 that operate the trunnion arm 35 for speed change operation of the continuously variable transmission 25, and a cruise lever 38 that maintains the forward pedal 36 in the stepping operation position. Is arranged. A trunnion arm 35 is connected to the forward pedal 36 and the reverse pedal 37 via a speed change link mechanism 300, and the stepless transmission 25 is operated by a stepping operation of the forward pedal 36 or the reverse pedal 37, so that the continuously variable transmission 25 is moved forward or reverse. A shifting operation is performed.

  The structure of the clutch housing 10, the transmission front case 12, and the transmission case 11 will be described with reference to FIGS. The interior of the clutch housing 10 is partitioned by a housing inner wall 50 so as to be divided into front and rear, and a housing front chamber 51 and a housing rear chamber 52 are formed inside the clutch housing 10. The interior of the mission front case 12 is partitioned by a front wall 53 so as to be divided into front and rear, and a front case front chamber 54 and a front case rear chamber 55 are formed inside the mission front case 12. The interior of the mission case 11 is partitioned by a mission inner wall 56 so as to be divided into front and rear, and a mission front chamber 57 and a mission rear chamber 58 are formed inside the mission case 11.

  In a closed space formed by the housing rear chamber 52 and the front case front chamber 54, a continuously variable transmission 25 disposed in front of the front wall 53 is provided. In the closed space formed by the front case rear chamber 55 and the mission front chamber 57, an auxiliary transmission gear mechanism 59 and a front wheel drive mechanism 60 are provided. A rear wheel differential gear mechanism 61 and a PTO output reduction gear mechanism 62 are provided inside the mission rear chamber 58.

  Next, the main transmission structure of the continuously variable transmission 25 will be described. The continuously variable transmission 25 includes a transmission hydraulic pump 63 and a transmission hydraulic motor 64 that is operated by the hydraulic pump 63 (see FIG. 7). A front end side of the transmission input shaft 65 of the continuously variable transmission 25 protrudes from the housing front chamber 51 through a through hole 50 a in the housing inner wall 50. The rear end side of the main drive shaft 26 is connected to the front end side of the speed change input shaft 65 via a coupling 66. A main transmission output shaft 67 of the continuously variable transmission 25 protrudes inside the front case rear chamber 55. A main transmission output gear 68 is fitted on the main transmission output shaft 67. A counter input gear 70 is fitted on the counter shaft 69 of the auxiliary transmission gear mechanism 59. A counter input gear 70 is engaged with the main transmission output gear 68. The continuously variable transmission output from the main transmission output shaft 67 is transmitted to the counter shaft 69 via the main transmission output gear 68 and the counter input gear 70.

  Next, the auxiliary transmission gear mechanism 59 will be described. The counter shaft 69 is integrally formed with a sub-speed first speed (low speed) counter gear 71 and a sub-speed second speed (medium speed) counter gear 72. Further, the counter shaft 69 is fitted with a sub-speed third speed (high speed) counter gear 73. Also, a sub-speed 1-speed output gear 74 meshed with the first-speed counter gear 71, a sub-speed 2-speed output gear 75 meshed with the 2-speed counter gear 72, and a 3-speed sub-gear 3 meshed with the 3-speed counter gear 73 A high-speed output gear 76 is provided. A first speed output gear 74 and a third speed output gear 76 are rotatably fitted to the sub transmission output shaft 77 of the sub transmission gear mechanism 59. The auxiliary transmission output shaft 77 is fitted with an auxiliary transmission slider 78 that is slidable in the axial direction and rotates integrally. A second speed output gear 75 is formed integrally with the auxiliary transmission slider 78.

  Therefore, the second-speed output gear 75 is engaged with the second-speed counter gear 72 by moving the auxiliary transmission slider 78 by operating the auxiliary transmission shifter 79. On the other hand, the first speed output gear 74 or the third speed output gear 76 is selectively connected to the auxiliary transmission slider 78 via the first speed clutch pawl 80 or the third speed clutch pawl 81. In other words, the rotation of the auxiliary transmission output shaft 77 is shifted in three stages via any one of the first speed output gear 74, the second speed output gear 75, and the third speed output gear 76.

  On the other hand, the rear end side of the auxiliary transmission output shaft 77 protrudes into the mission rear chamber 58. A pinion gear 82 for transmitting a rotational force to the rear wheel differential gear mechanism 61 is integrally formed on the rear end side of the auxiliary transmission output shaft 77. The power from the auxiliary transmission output shaft 77 is transmitted to the left and right rear wheels 4 via the pinion gear 82 and the differential gear mechanism 61.

  Next, the front wheel drive mechanism 60 will be described. A front wheel output shaft 85 of the front wheel drive mechanism 60 is connected to the front end side of the auxiliary transmission output shaft 77 via front wheel drive gears 83 and 84. A front wheel drive gear 84 that is rotatably fitted on the rear end side of the front wheel output shaft 85 protruding into the front case rear chamber 55, and the front wheel drive gear 84 is engaged with and disengaged from the front wheel output shaft 85. A front wheel output clutch 86 is arranged for locking in a possible manner. Further, an intermediate portion of the front wheel output shaft 85 is supported by the front wall 53 via a ball bearing. The front end side of the front wheel output shaft 85 protrudes into the front case front chamber 54.

  The rear end side of the front wheel transmission shaft 88 is connected to the front end side of the front wheel output shaft 85 via a universal shaft joint 250. The front end side of the front wheel transmission shaft 88 is extended toward the front side of the traveling machine body 2, and the driving force is transmitted from the front end side of the front wheel transmission shaft 88 to the front wheel 3 via the front axle case 7. . The front wheel transmission shaft 88 is fitted with a shaft cover 89 made of synthetic resin pipe, and the front wheel transmission shaft 88 is protected by the shaft cover 89.

  As shown in FIG. 7, a front wheel drive extraction shaft 85 is disposed between the continuously variable transmission 25 and the transmission link mechanism 300. That is, the hydraulic continuously variable transmission 25 is fixed to the transmission front case 12 while being inclined toward the right side of the traveling machine body 2 in a front view. A space for installing the front wheel drive take-off shaft 85 can be easily secured in the transmission front case 12 with the link mechanism 300.

  In addition, the shift link mechanism 300 disposed on the right side of the traveling machine body 2 in the traveling direction and the lower end side of the trunnion arm 35 disposed on the right side of the hydraulic continuously variable transmission 25 are brought close to each other, so that the clutch housing 10 right side walls can be arranged to face each other. In addition, the right side surface of the hydraulic continuously variable transmission 25 and the upper end side of the trunnion arm 35 can approach each other, and the trunnion shaft 301 for supporting the trunnion arm 35 on the hydraulic continuously variable transmission 25 can be formed in a short length. Become. The trunnion shaft 301 is formed from a base material of a hexagonal columnar rod body by cutting, and assembled to the case of the hydraulic continuously variable transmission 25 from the outside of the clutch housing 10 to form a trunnion shaft 301 formed into a square column shape. A trunnion arm 35 is detachably fixed to the distal end side of the head.

  FIG. 8 shows a hydraulic circuit 200 of the tractor 1 according to this embodiment, which includes a working machine hydraulic pump 94 and a charging hydraulic pump 95 that are operated by the rotational force of the engine 5. The charging hydraulic pump 95 is connected to a double-acting steering hydraulic cylinder 202 for power steering by the steering handle 16 via a steering control valve 201 for power steering. The working machine hydraulic pump 94 is connected to a lifting hydraulic switching valve 204 for supplying hydraulic oil to a single-acting lifting hydraulic cylinder 203 in the working machine lifting mechanism 20.

  Therefore, the operator operates the position lever 205 to switch the lifting hydraulic switching valve 204 to operate the lifting hydraulic cylinder 203 and rotate the lift arm 20a, so that the work machine 19 is connected via the lower link 22. Will be raised or lowered.

  As shown in FIG. 8, the variable displacement shift hydraulic pump 63 of the hydraulic continuously variable transmission 25 described above, and a constant displacement shift hydraulic pressure that operates with high-pressure hydraulic fluid discharged from the hydraulic pump 63. The suction side and discharge side of the motor 64 are connected via a closed loop oil passage 207. By adjusting the angle of the swash plate 208 of the transmission hydraulic pump 63 driven through the transmission input shaft 65, the rotational speed of the main transmission output shaft 67 driven through the transmission hydraulic motor 64 is changed. become. The hydraulic circuit 200 described above includes a relief valve, a flow rate adjustment valve, a check valve, an oil cooler, an oil filter, and the like, as shown in FIG.

  Next, with reference to FIGS. 9 to 15, a mounting structure for the forward pedal 36 and the reverse pedal 37 will be described. As shown in FIGS. 9 and 13, the base frame 310 is detachably fastened to the side surface on the right side in the traveling direction of the clutch housing 10 by a plurality of bolts 311. A vertical plate 314 is integrally fixed to the base frame 310 by welding via front and rear horizontal plates 312 and 313. That is, the pedal unit frame 309 that is rectangular in plan view for assembling the forward pedal 36 and the reverse pedal 37 is formed of the base frame 310, the front and rear lateral plates 312 and 313, and the longitudinal plate 314. The pedal unit frame 309 is disposed on the right side surface of the clutch housing 10 below the right step frame 13 in the traveling direction (forward).

  As shown in FIGS. 12 and 13, the base frame 310 and the vertical side plate 314 extend along the right side surface of the clutch housing 10 so as to be substantially parallel to the front-rear direction (traveling direction) of the traveling machine body 2. . The forward pedal shaft 315 and the reverse pedal shaft 316 are pivotally supported on the base frame 310 and the vertical side plate 314, and the forward pedal shaft 315 and the reverse pedal shaft 316 are disposed between the front and rear lateral plates 312 and 313. One end sides of the forward pedal shaft 315 and the reverse pedal shaft 316 protrude outward from the vertical side plate 314. A boss 318 on the base end side of the pedal arm 317 of the forward pedal 36 is fitted on one end side of the forward pedal shaft 315 on the outer side of the vertical side plate 314. Further, the boss portion 320 on the base end side of the pedal arm 319 of the reverse pedal 37 is fitted on one end side of the reverse pedal shaft 316 on the outer side of the vertical side plate 314.

  Accordingly, the forward pedal 36 and the reverse pedal 37 are disposed so as to be rotatable around the axis lines of the forward pedal shaft 315 and the reverse pedal shaft 316. The pedal arm 317 of the forward pedal 36 and the pedal arm 319 of the backward pedal 37 are provided so as to project diagonally forward and upward from the forward pedal shaft 315 and the backward pedal shaft 316, and the backward pedal 37 is obliquely rearward of the forward pedal 36. Is arranged. Both the forward pedal 36 and the reverse pedal 37 are stepped on in substantially the same direction diagonally forward and downward. The stepping operation directions (obliquely forward and downward) of the clutch pedal 31, the brake pedal 33, the forward pedal 36, and the reverse pedal 37 described above substantially coincide with each other.

  As shown in FIGS. 12 and 14, stop arms 321 and 322 are fixed to the boss portion 318 of the forward pedal shaft 315 and the boss portion 320 of the reverse pedal shaft 316. Bolt-shaped forward stoppers 323 and reverse stoppers 324 for bringing the stop arms 321 and 322 into contact with each other are arranged on the outer surface of the vertical side plate 314. A forward stopper 323 and a backward stopper 324 are screwed onto a stopper receiving bracket 325 fixed to the vertical side plate 314 by welding so that the amount of protrusion can be adjusted. Accordingly, the stop arms 321 and 322 come into contact with the forward stopper 323 and the reverse stopper 324, and the stepping operation in the speed increasing direction of the forward pedal 36 and the reverse pedal 37 is restricted, and the maximum speed on the forward side and the reverse side is set to the forward stopper 323. And the reverse stopper 324 is set.

  As shown in FIG. 11 and FIG. 14, the proximal end portion of the pressing arm 326 is fixed to the forward pedal shaft 315, and the contact roller 328 is rotatable at the distal end portion of the pressing arm 326 via the roller shaft 327. Pivot. Further, the base end portion of the swing arm 329 is fixed to the reverse pedal shaft 316. The swing arm 329 is integrally formed with a pressure receiving piece 330 and a locking piece 331. The pressure receiving piece 330 is brought into contact with the contact roller 328, and a tension spring 332 is connected to the roller shaft 327 and the locking piece 331. Therefore, the contact roller 328 and the pressure receiving piece 330 always come into contact with each other by the spring force of the tension spring 332.

  Further, as shown in FIGS. 11 and 14, the base end portion of the speed change arm 333 is fixed to the reverse pedal shaft 316, and the front end portion of the speed change arm 333 is expanded and contracted via the connecting pin 334 and the joint bracket 335. One end of the adjustable speed change rod 336 is connected. The other end side of the speed change rod 336 is connected to the trunnion arm 35 described above via a connecting shaft 337.

  Further, the neutral adjustment body 340 is fixed to the outer surface of the clutch housing 10 by one fulcrum bolt 342 for neutral adjustment and two neutral adjustment bolts 343. A locking shaft 341 is fixed to the clutch housing 10 via a neutral adjustment body 340. Both ends of the neutral holding spring 339 are locked to the connecting shaft 337 and the locking shaft 341. A spring-type neutral holding spring 339 is disposed in the clutch housing 10 via a spring holder 338. The neutral adjustment bolt 343 is passed through the long hole-type neutral adjustment hole 344 of the neutral adjustment body 340. A speed change limiting hole 345 is formed in the neutral adjustment body 340, and the connecting shaft 337 is passed through the long hole-type speed change limiting hole 345.

  As shown in FIG. 11, the speed limiting hole 345 is formed long in the circumferential direction around the trunnion shaft 301. Therefore, the trunnion arm 35 is rotated forward or backward about the trunnion shaft 301 in the continuously variable transmission range in which the connecting shaft 337 moves in the speed limiting hole 345.

  On the other hand, the neutral adjustment hole 344 of the neutral adjustment body 340 is formed long in the circumferential direction around the fulcrum bolt 342. Therefore, the neutral adjustment bolt 343 is loosened, and the neutral adjustment body 340 is rotated around the fulcrum bolt 342. As a result, the locking shaft 341 is moved to adjust the neutral (output zero) position, and the shift limiting hole 345 is moved to the forward shift side or the reverse shift side to shift the trunnion arm 35 (connection shaft 337). The range is adjusted, the shift operation range of the trunnion arm 35 on either the forward shift side or the reverse shift side is expanded, and the other continuously variable shift range is reduced.

  As shown in FIGS. 12 and 14, the base end portion of the pedaling force adjustment link 346 is fixed to the forward pedal shaft 315. One end side of the pedal force frame 349 is connected to one of a plurality of pedal force adjustment holes 347 formed in the pedal force adjustment link 346 via a pedal force adjustment pin 348. Further, the base end portion of the connection link 351 and the base end portion of the pedaling force link 352 are fixed to the rotatable cylindrical shaft body 350 on the pedal operation shaft 262 described above. A distal end portion of the connection link 351 is connected to the other end side of the pedaling force frame 349 via a connection pin 353. A pedal force damper 355 is connected to the tip of the pedal force link 352 via a support pin 354. The pedal force damper 355 is assembled to the outside of the clutch housing 10 via a damper mounting shaft 356 (see FIG. 5).

  Next, the shifting operation of the continuously variable transmission 25 executed by operating the forward pedal 36 and the reverse pedal 37 will be described. First, when an operator sitting on the control seat 17 depresses the forward pedal 36 with the right foot, the pressing arm 326 is rotated around the forward pedal shaft 315 and the swing arm 329 is moved backward by the contact roller 328. Rotate around 316. The transmission arm 333 is rotated on the reverse pedal shaft 316 by the rotation of the swing arm 329, the transmission rod 336 is pushed by the transmission arm 333, and the trunnion arm 35 and the trunnion shaft 301 are resisted against the force of the neutral holding spring 339. Rotates in the forward direction (clockwise in FIG. 11), operates the continuously variable transmission 25 to the forward side, drives the front wheels 3 and the rear wheels 4 to the forward side, and moves the traveling machine body 2 in the forward direction. Let

  Therefore, when the forward pedal 36 is depressed, the moving speed of the traveling machine body 2 can be changed in proportion to the amount of depression of the forward pedal 36, and the speed limit of the connecting shaft 337 is limited until the stop arm 321 contacts the forward stopper 323. The forward pedal 36 can be depressed to increase the speed toward the forward side until it contacts the one end side of the hole 345. Further, when the forward pedal 36 is stepped on and the swing arm 329 is rotated, the reverse pedal 37 is rotated around the reverse pedal shaft 316 in the direction opposite to the stepping operation direction.

  On the other hand, when the operator sitting on the control seat 17 steps on the reverse pedal 37 with the right foot, the transmission arm 333 on the reverse pedal shaft 316 is rotated via the swing arm 329, and the transmission rod 333 is rotated by the transmission arm 333. 336 is pulled, the trunnion arm 35 and the trunnion shaft 301 are rotated in the reverse direction (counterclockwise in FIG. 11) against the force of the neutral holding spring 339, and the above-described continuously variable transmission 25 is operated in the reverse direction. Then, the front wheel 3 and the rear wheel 4 are driven backward, and the traveling machine body 2 is moved in the reverse direction.

  Therefore, when the reverse pedal 37 is depressed, the moving speed of the traveling machine body 2 can be changed in proportion to the amount of depression of the reverse pedal 37 until the stop arm 322 comes into contact with the reverse stopper 324 or the connection shaft 337 is limited in speed change. The reverse pedal 37 can be depressed to increase the reverse speed until it contacts the other end of the hole 345. Further, when the reverse pedal 37 is depressed, the pressing arm 326 is rotated via the contact roller 328 by the rotation of the swing arm 329, and the forward pedal 36 is moved in the direction opposite to the stepping operation direction. It is rotated around 315.

  When the foot is released from the forward pedal 36 or the reverse pedal 37, the forward pedal 36 and the reverse pedal 37 gently return to the neutral position (output zero position) due to the restriction of the pedal force damper 355 by the neutral holding spring 339 force, The shift output of the continuously variable transmission 25 is maintained at substantially zero.

  Next, referring to FIG. 9, FIG. 11, FIG. 14 and FIG. 15, a vehicle speed maintenance mechanism (automatic mechanism) for maintaining the vehicle speed of the traveling machine body 2 at a predetermined level by holding the forward pedal 36 in the predetermined depression position. The cruise mechanism will be described. The vehicle speed maintaining mechanism 361 includes a plurality of locking claws 362 and a single locking body 363 that are detachably engaged. The locking body 363 and the locking claw 362 are disposed so as to face each other so as to be able to contact and separate.

  As shown in FIG. 9, one end side of the clutch operation shaft 302 is protruded from the clutch housing 10 to the right side of the traveling machine body 2 in the traveling (forward) direction, and a side view L is formed at the protruding end portion of the clutch operation shaft 302. The middle of the locking link 364 is pivotally supported, one end of the locking link 364 is connected to the cruise lever 38 as a manual operation lever, and the other end of the locking link 364 is a protrusion-shaped engagement. The stop body 363 is formed integrally.

  As shown in FIG. 11, one end of an arcuate locking arm 365 in a side view is connected to the forward pedal shaft 315, and a plurality of locking claws 362 are continuously provided on the outer peripheral edge of the other end of the locking arm 365. Form. The direction in which the locking body 363 engages or disengages from the locking claw 362 is made substantially orthogonal to the tangent of the circumferential locus in which the locking arm 365 is rotated by the neutral holding spring 339. Engagement surfaces of the locking claw 362 and the locking body 363 are substantially orthogonal to the tangent line of the circular locus on which the locking arm 365 rotates. Therefore, when the forward pedal 36 is further depressed in the speed increasing direction, the locking body 363 is released in the direction of disengagement by the speed increasing side locking claw 362 adjacent to the locking claw 362 engaged with the locking body 363. The engagement between the locking claw 362 and the locking body 363 is released.

  That is, the shape of the locking claw 362 and the locking body 363 is such that the rotational moment that the locking arm 365 rotates by the neutral holding spring 339 acts as a force for engaging the locking body 363 with the locking claw 362. Form. The turning force (neutral holding spring 339 force) of the locking arm 365 for engaging the locking body 363 with the locking claw 362 is the force of the cutting holding spring 366 for holding the cruise lever 38 at the cutting position of the steering column 15. It becomes several times larger than (the force for releasing the locking body 363 from the locking claw 362) or several times larger than the operating force for the operator to move the cruise lever 38 from the vehicle speed maintaining position (entering position) to the cutting position. Thus, the latching arm 365 is configured to return to the initial position by the neutral holding spring 339.

  Therefore, the locking body 363 does not disengage from the locking claw 362 by the force that returns the cruise lever 38 to the cutting position by the cutting holding spring 366. Further, the locking body 363 does not disengage from the locking claw 362 by the pushing operation force that returns the cruise lever 38 from the vehicle speed maintenance position (entry position) to the cutting position. The rotational moment that the locking arm 365 is rotated by the neutral holding spring 339 acts as an engaging force on the locking claw 362 and the locking body 363, and the forward pedal 36 is returned from the depressed position to the initial position, so that the vehicle speed is substantially zero. The engagement of the locking claw 362 and the locking body 363 can be maintained by the force of the neutral holding spring 339 as an initial position return spring.

  Next, the vehicle speed maintaining operation (auto cruise operation) of the vehicle speed maintaining mechanism (auto cruise mechanism) 361 described above will be described with reference to FIGS. When the cruise lever 38 is pulled up against the cutting and holding spring 366 by the operator while the forward pedal 36 is depressed by the operator, the locking link 364 is moved from the imaginary line position to the solid line position as shown in FIG. It rotates around the clutch operating shaft 302 and the locking body 363 is engaged with the locking claw 362. Therefore, even if the operator removes his / her foot from the forward pedal 36, the forward pedal 36 is maintained in the depressed position, the front wheels 3 and the rear wheels 4 are driven at a substantially constant speed, and tilling work etc. while moving at a substantially constant speed. Is done. On the other hand, when the forward pedal 36 is depressed by the operator while the locking body 363 is engaged with the locking claw 362, the locking body 363 is released from the locking claw 362 and the cruise lever 38 and the engagement lever 362 are engaged. The stop link 364 is cut from the solid line position to the virtual line position (initial position) and returned by the holding spring 366, and the vehicle speed holding operation (auto cruise operation) that moves at a substantially constant speed is released.

  As apparent from FIGS. 9, 11, and 15, the engine 5 mounted on the traveling machine body 2 including the front wheel 3 and the rear wheel 4 as a traveling unit, and the hydraulic type that shifts the power from the engine 5 are not used. A transmission case 25 for transmitting a shift output from the hydraulic continuously variable transmission 25 to the front wheels 3 and the rear wheels 4 via a sub-transmission gear mechanism 59 as a shift output gear, and a hydraulic continuously variable transmission A forward pedal 36 and a reverse pedal 37 as shift pedals connected to a trunnion arm 35 as a speed change operation portion of the machine 25 via a speed change link mechanism 300 and a stepping operation position of the forward pedal 36 and the reverse pedal 37 The vehicle speed maintaining mechanism 361 includes a plurality of locking claws 362 that are detachably engaged with each other. 65 and a locking body 363, a locking arm 365 is connected to the forward pedal 36, a locking body 363 is connected to a cruise lever 38 as a manual operation lever for maintaining the vehicle speed, and the forward pedal 36 and the reverse pedal The engagement between the locking claw 362 and the locking body 363 can be maintained by the biasing force of the neutral holding spring 339 as an initial position return spring for returning the vehicle 37 to the initial position from the stepping position to make the vehicle speed substantially zero. Since it is configured, a locking claw is utilized by using a force that returns the forward pedal 36 and the reverse pedal 37 from the depressed position to the initial position (force that returns the shift output of the hydraulic continuously variable transmission 25 to zero). The engagement between 362 and the locking body 363 can be continued. That is, since the operating force of the cruise lever 38 that the operator pushes (pulls) with one hand is smaller than the stepping force of the forward pedal 36 that the operator steps on with her foot, the force of the neutral holding spring 339 is larger than the operating force of the cruise lever 38 The engagement between the locking claw 362 and the locking body 363 is not easily released by the operation of the cruise lever 38. Therefore, it is possible to easily prevent the engagement between the locking claw 362 and the locking body 363 due to an erroneous operation of the cruise lever 38, and to improve driving operability. Even if the neutral holding spring 339 force is larger than the operating force of the cruise lever 38, the operator can easily step on the forward pedal 36 and the reverse pedal 37 with his / her foot, and the trunnion arm of the hydraulic continuously variable transmission 25. 35 can easily be returned to the output zero position.

  As is clear from FIG. 15, the locking link 364 is rotatably arranged on the traveling machine body 2, one end side of the locking link 364 is connected to the cruise lever 38, and the locking link 364 is locked to the other end side. Since the body 363 is disposed, the locking body 363 is integrally formed on the locking link 364 as compared with the conventional structure in which a plurality of locking claws 362 are formed on the locking link 364. The stop link 364 can be configured to be lightweight and simple. Therefore, since the locking body 363 can be easily supported at a position away from the locking claw 362 by a spring force smaller than the neutral holding spring 339 force, the cruise lever for engaging the locking body 363 with the locking claw 362 The operation force of 38 can be reduced.

  As apparent from FIGS. 14 and 15, one end side of the locking arm 365 is connected to the forward pedal 36, and a plurality of locking claws 362 are formed on the other end side of the locking arm 365. Since the locking body 363 and the locking claws 362 of the locking arm 365 are arranged to face each other, the strength of the plurality of locking claws 362 formed on the locking arm 365 can be easily improved. That is, even if the locking arm 365 is formed with high rigidity so that the strength of the locking claw 362 is improved, the locking arm 365 can be made lighter than the forward pedal 36. Compared to the conventional structure in which the pawl 362 is formed, the highly rigid locking arm 365 and the locking pawl 362 can be easily formed without impairing the speed change function of the forward pedal 36.

  As is apparent from FIGS. 11 and 14, the shift pedal is composed of a forward pedal 36 and a reverse pedal 37, and the forward pedal 36 and the reverse pedal 37 are returned from the depressed position to the initial position by the spring force of one neutral holding spring 339. In addition, since the trunnion arm 35 of the hydraulic continuously variable transmission 25 is configured to be returned to the output zero position, the output zero position of the trunnion arm 35 of the hydraulic continuously variable transmission 25 can be simply set. Can be set. In other words, the output zero adjustment unit that maintains the trunnion arm 35 at the output zero position by the neutral holding spring 339 and the initial position adjustment unit that returns the forward pedal and the reverse pedal to the initial position by the neutral holding spring 339 also serve as adjustment parts. The neutral adjustment body 340 as an output zero adjustment part and an initial position adjustment part etc. can be comprised easily. Therefore, the assembly workability and maintenance workability of the forward pedal 36 and the reverse pedal 37 can be improved.

  As is apparent from FIGS. 12 and 14, the pedal unit frame 309 as the pedal frame of the traveling machine body 2 is pivotally connected to the forward pedal 36 and the reverse pedal 37 via the forward pedal shaft 315 and the reverse pedal shaft 316, respectively. A pressing arm 326 as a check mechanism that supports one of the forward pedal 36 and the reverse pedal 37 and the trunnion arm 35 of the continuously variable transmission 25 to prevent simultaneous depression of the forward pedal 36 and the reverse pedal 37; The forward pedal 36 and the reverse pedal 37 are connected via the swing arm 329 so that the respective depression operation directions of the forward pedal 36 and the reverse pedal 37 are substantially matched. The forward pedal 36 and the reverse pedal 37 can be stepped on the front side of the foot. For example, the forward pedal 36 and the reverse pedal 37 can be disposed close to the front side of the right foot of the operator seated on the control seat 17 of the traveling machine body 2, and the operator moves the right foot to the left and right to move the forward pedal 36 or the reverse pedal 37. Can be stepped on. Therefore, compared with the conventional structure in which the operator steps on the forward pedal 36 on the front side of the foot and the reverse pedal 37 on the rear side of the foot, the function of preventing the simultaneous depression operation of the forward pedal 36 and the reverse pedal 37 is not impaired. The stepping operability of 37 can be improved.

  Next, with reference to FIGS. 5 and 15 to 21, the mounting structure of the brake pedal 33 as the brake operating means will be described. As shown in FIGS. 5 and 19, the brake pedal shaft 371 is detachably fixed to the left and right bearing brackets 370 of the step frame 13 described above. The left and right bearing brackets 370 extend substantially parallel to the front-rear direction of the traveling machine body 2. A boss portion 373 on the base end side of the pedal arm 372 of the brake pedal 33 is fitted between the left and right bearing brackets 370 via the brake pedal shaft 371. A fastening plate 375 on the right end side of the brake pedal shaft 371 is fastened to the right bearing bracket 370 from the outside of the traveling machine body 2 via a bolt 374. The brake pedal 33 is removed from the step frame 13 by removing the bolt 374 and extracting the brake pedal shaft 371 to the outside of the bearing bracket 370.

  As shown in FIGS. 5, 15, and 19, the boss portion 373 of the pedal arm 372 is connected to the pedal operation shaft 262 described above via the brake link mechanism 381. The brake link mechanism 381 includes one brake arm 376 fixed to the pedal operation shaft 262 via the arm boss portion 382, the other brake arm 377 fixed to the boss portion 373, and a pin 378 to each brake arm 376, 377. , 379, and a brake link 380 connected thereto. The brake rod 32 a is connected to the arm boss portion 382 via the rod arm 383. Further, the hook arm 384 and the rod arm 383 of the vertical side plate 314 are connected by a brake release spring 385. The brake pedal 33 is maintained at the initial position by the brake release spring 385, and the braking operation of the brake mechanism 32 is held in a state released by the brake release spring 385.

  A parking brake structure that maintains the brake pedal 33 in the depressed position will be described with reference to FIGS. 17, 20, and 21. As shown in FIG. 17, the base end side of the lock arm 386 is fixed to the boss portion 373 of the pedal arm 372, and the locking projection 387 is integrally formed on the distal end side of the parking arm 386. Further, the rear end side of the fulcrum frame 388 is fixed to the front side of the step frame 13 described above, the arm support shaft 389 is disposed on the front end side of the fulcrum frame 388, and the base end side of the parking arm 390 is disposed on the arm support shaft 389. The boss portion 393 is pivotally supported. The parking arm 390 is formed with a plurality of locking notches 391 and a locking guide surface 392 for locking the locking projection 387 so as to be detachable.

  As shown in FIGS. 17 and 20, the pressure receiving arm 394 is fixed to the boss portion 393 on the base end side of the parking arm 390. The pressure receiving arm 394 is formed with a long hole 395 that is long in the circumferential direction around the arm support shaft 389. Further, the pressure arm 396 is pivotally supported on the arm support shaft 389, the pressure pin 397 is fixed to the pressure arm 396, and the pressure pin 397 is passed through the long hole 395. A pressure spring 398 is wound around the outer periphery of the boss portion 393, one end side of the pressure spring 398 is locked to the pressure receiving arm 394, and the other end side of the pressure spring 398 is locked to the pressure pin 397. The locking projection 387 is elastically pressed against the locking notch 391 and the locking guide surface 392 by the urging force of the pressure spring 398.

  On the other hand, the step board 399 of the step frame 13 is fastened to the side surface of the clutch housing 10 by the bolt 400. The parking brake lever 34 is disposed on the side surface of the clutch housing 10 above the step board 399 via the lever guide frame 401 so as to be vertically movable in the standing posture. A lever shaft 404 is pivotally supported via a pin shaft body 403 between the shaft bracket 402 of the step frame 13 and the step board 399. The first arm 405 of the lever shaft 404 is connected to the lower end side of the parking brake lever 34 via the pin 406. One end side of the parking link 409 is connected to the second arm 407 of the lever shaft 404 via the pin 408.

  On the other hand, the pressure arm 396 described above is connected to the other end side of the parking link 409 via a pin 410. The pin 410 and the other end side of the fulcrum passing arm 412 having one end fixed to the fulcrum frame 388 are connected by a fulcrum passing spring 411. That is, the parking brake lever 34 is maintained by the fulcrum overspring 411 at the parking brake on position on the ascending side or the parking brake off position on the descending side.

  The parking brake operation for maintaining the brake pedal 33 in the depressed position by operating the parking brake lever 34 will be described with reference to FIGS. 16 and 17. An operator sitting on the control seat 17 steps on the brake pedal 33 with the right foot, operates the brake mechanism 32, and brakes the left and right rear wheels 4. When the brake pedal 33 is thus depressed, the lock arm 386 and the locking projection 387 rotate around the brake pedal shaft 371 (the arrow in FIG. 17, clockwise rotation) and engage with the locking notch 391. The locking projection 387 moves to a possible position.

  Further, with the rear wheel 4 braked, the operator grips the grip part 34a of the parking brake lever 34 with the right hand and raises the parking brake lever 34 in the lowered (parking brake off) position to the (with parking brake) position. In this case, the pressure arm 396 is rotated against the fulcrum spring 411 and the parking brake lever 34 is held in the raised position by the fulcrum spring 411. The pressure pin 397 is rotated around the arm spindle 389 by the rotation of the pressure arm 396, and the pressure receiving arm 394 and the parking arm 390 are rotated in conjunction with each other via the pressure pin 397, and the locking protrusion 387. The locking guide surface 392 comes into contact with this. Therefore, when the operator releases the right foot from the brake pedal 33, the locking projection 387 is engaged with the locking notch 391 by the guide of the locking guide surface 392, and the brake pedal 33 is maintained in the depressed position. Therefore, even if the operator releases the right foot from the brake pedal 33, the braking of the left and right rear wheels 4 is continued, the parking brake mechanism 32 is held in the on state, and the braking of the rear wheels 4 is maintained.

  On the other hand, when the operator grips the grip portion 34a of the parking brake lever 34 with the right hand and pulls the parking brake lever 34 in the raised (parking brake on) position to the lowered (parking brake off) position, the operator moves against the fulcrum spring 411. Thus, the pressure arm 396 is rotated, and the parking brake lever 34 is held in the lowered position by the fulcrum spring 411. By the rotation of the pressure arm 396, the pressure pin 397 rotates about the arm support shaft 389, and the pressure receiving arm 394 and the parking arm 390 are interlocked via the pressure pin 397 by the urging force of the pressure spring 398. The locking notch 391 is separated from the locking projection 387, and the brake pedal 33 is returned from the depressed position to the initial position by the urging force of the brake release spring 85. Therefore, when the operator releases the right foot from the brake pedal 33, the braking of the left and right rear wheels 4 is released, and the parking brake mechanism 32 is held in the off state.

  Next, referring to FIGS. 15, 18, 20, and 21, a brake system auto-cruise canceling structure that cancels the vehicle speed maintaining operation of the vehicle speed maintaining mechanism 361 described above by depressing (braking) the brake pedal 33. Will be explained. As shown in FIGS. 18 and 20, the above-described fulcrum frame 388 is made to penetrate one end side of a round bar-shaped release arm 413 as a braking system release means. One end side of the release arm 413 penetrating the fulcrum frame 388 is disposed substantially parallel to the brake pedal shaft 371 extending in the left-right direction of the traveling machine body 2. The protruding end side of the release arm 413 protruding to the right side of the fulcrum frame 388 and the lock arm 386 are connected via the release link mechanism 414. The release link mechanism 414 includes a first link 416 that rotatably connects one end side to the lock arm 386 via a pin 415, and a second link 417 that has one end side fixed to the protruding end side of the release arm 413. Have The other end side of the first link 416 and the other end side of the second link 417 are connected via a pin 418 so as to be rotatable. In conjunction with the operation of the brake pedal 33 that rotates about the brake pedal shaft 371, the release arm 413 rotates about the axis line via the lock arm 386 and the release link mechanism 414.

  On the other hand, as shown in FIG. 20, the other end side of the release arm 413 protrudes to the right side of the fulcrum frame 388, and the other end side of the release arm 413 is bent into a substantially L shape so that the release operation portion 413a is integrated. To form. In addition, a round bar-shaped release protrusion 419 is fixed to the above-described locking link 364, and the release operation portion 413a and the release protrusion 419 are arranged on a straight line extending in the airframe traveling direction (front-rear direction). .

  An auto-cruise canceling operation of the braking system that cancels the vehicle speed maintaining operation of the vehicle speed maintaining mechanism 361 described above will be described. With the forward pedal 36 depressed by the operator, as shown in FIG. 15, the cruise lever 38 is pulled up from the phantom line position to the solid line position by the operator, and the locking link 364 is clutched from the phantom line position to the solid line position. When the locking body 363 is engaged with the locking claw 362 and the vehicle speed maintaining mechanism 361 is maintained in the auto-cruise (vehicle speed maintaining) state, the release arm is depressed by depressing the brake pedal 33. When 413 rotates around the axis line, the release operation portion 413a comes into contact with the release protrusion 419, and the locking link 364 at the solid line position is forcibly moved in the direction of the virtual line position.

  Therefore, the locking body 363 is forcibly released from the locking claw 362, the vehicle speed maintenance mechanism 361 is switched to the released state, the forward pedal 36 returns from the depressed position to the initial position, and the speed change from the continuously variable transmission 25 is performed. The output returns to approximately zero. As shown in FIG. 15, when the cruise lever 38 is pushed down to the auto-cruise cut (virtual line) position, the locking link 364 moves from the solid line position to the virtual line position ahead of the aircraft, and the locking body 363. Is held at a disengaged position separated from the locking claw 362. As described above, when the vehicle speed maintaining mechanism 361 is held in the released state, the release protrusion 419 is positioned outside the rotation trajectory range of the release operation unit 413a. Even if it rotates around, the release operation portion 413 a does not contact the release protrusion 419. Therefore, the brake pedal 33 can be operated in a state where the cruise lever 38 is securely held at the off position.

  As apparent from FIGS. 15, 17, 18, and 20, the engine 5 mounted on the traveling machine body 2 including the front wheel 3 and the rear wheel 4 as a traveling unit, and the power from the engine 5 are shifted. A hydraulic continuously variable transmission 25, a transmission case 11 for transmitting a shift output from the hydraulic continuously variable transmission 25 to a front wheel 3 and a rear wheel 4 via a sub transmission gear mechanism 59 as a shift output gear; A forward pedal 36 and a reverse pedal 37 as shift pedals connected to a trunnion arm 35 as a shift operation portion of the continuously variable transmission 25 via a shift link mechanism 300 as a shift link mechanism, and an arbitrary depression of the forward pedal 36 In a work vehicle including a vehicle speed maintaining mechanism 361 that is held at an operation position, and a brake pedal 33 as a brake operation unit that brakes the front wheel 3 and the rear wheel 4, A release arm 413 is provided as a braking system release means for forcibly releasing the vehicle speed maintenance mechanism 361 by a braking operation of the rake pedal 33, and a traveling system release operation for releasing the vehicle speed maintenance mechanism 361 by the forward pedal 36 and a release arm 413 Since the brake system releasing operation for releasing the vehicle speed maintaining mechanism 361 can be executed independently, two release means for the traveling system and the braking system can be formed independently, The vehicle speed maintenance mechanism 361 can be forcibly released by at least one of two independent release systems of the traveling system and the braking system. For this reason, even if any one of the release means malfunctions, the vehicle speed maintenance mechanism 361 can be released by the other release means, and the reliability of the vehicle speed maintenance function and the release function can be improved.

  As apparent from FIGS. 15 and 18, the vehicle speed maintaining mechanism 361 can be engaged with and disengaged from the locking arm 365 having a plurality of locking claws 362 for maintaining the forward pedal 36 in the depressed position, and the locking claw 362. A locking link 364 is connected to the cruise lever 38 as a manual operation lever for maintaining the vehicle speed, the locking link 364 is disposed on the locking link 364, and brake operating means is provided. The brake link 33 is connected to the brake pedal 33 via a release arm 413 as a braking system release means for forcibly releasing the lock body 363 from the lock claw 362. The braking system release means for forcibly releasing the locking body 363 from the locking claw 362 can be easily configured by the release arm 413, and the vehicle speed maintaining function and the reliability of the release function, etc. It is those that can be improved.

  As apparent from FIGS. 18, 20, and 21, the brake pedal 33 and the release arm 413 are arranged on the step frame 13 of the traveling machine body 2, and the brake pedal 33 and the release arm 413 are connected by the release link mechanism 414. Therefore, the brake pedal 33 and the release arm 413 can be supported with high rigidity by the step frame 13, and the brake pedal 33 and the release arm 413 can be easily configured by the low-cost release link mechanism 414. It can be connected.

  As is clear from FIG. 15, the locking link 364 is rotatably disposed on the link support shaft 302 of the traveling machine body 2, one end side of the locking link 364 is connected to the cruise lever 38, and the other of the locking links 364. Since the locking body 363 is disposed on the end side and the locking link 364 can be moved by the release arm 413 in the direction in which the locking body 363 is separated from the locking claw 362, By operating the release arm 413 with a relatively small operating force, the locking link 364 can be easily moved, and the vehicle speed maintaining mechanism 361 can be forcibly released. Therefore, the engagement between the locking claw 362 and the locking body 363 can be reliably maintained by using a relatively large urging force such as the neutral holding spring 339 that returns the forward pedal 36 and the reverse pedal 37 to the initial positions. is there.

  As apparent from FIGS. 11 and 13, the shift pedal includes a forward pedal 36 and a reverse pedal 37, and a pedal unit frame 309 as a pedal frame is detachably disposed on the traveling body 2, and the pedal unit frame Since the forward pedal 36 and the reverse pedal 37 are pivotally supported by a forward pedal shaft 315 and a reverse pedal shaft 316 at 309, the traveling machine body 2 is supported by the pedal unit frame 309. The assembly and disassembly work of the forward pedal 36 and the reverse pedal 37 to be assembled and the assembly and disassembly work of the brake pedal 33 to be assembled to the step frame 13 can be performed separately. In addition, the assembly and disassembly workability of the brake pedal 33 can be improved. Further, the forward pedal 36, the reverse pedal 37, and the brake pedal 33 can be disposed close to each other in a place where the operator can easily depress with the right foot, and the forward pedal 36, the reverse pedal 37, and the brake pedal 33 are depressed. Can be improved.

  Next, referring to FIGS. 7, 11, 14, and 22, the above-described structure for limiting the shifting operation of the continuously variable transmission 25, the structure for adjusting the shift neutral position of the continuously variable transmission 25, and A structure for maintaining the shift pedals (forward pedal 36 and reverse pedal 37) at the initial position will be described. As shown in FIG. 7 and FIG. 11, the bifurcated base end side of the trunnion arm 35 is fixed to the quadrangular column portion of the trunnion shaft 301 by tightening bolts 421 and nuts 422. A nut body 423 is fixed to the distal end side of the trunnion arm 35 by welding, and a base end screw portion of a hexagonal column-shaped connecting shaft 337 is screwed to the nut body 423 in the clutch housing 10, and the connecting shaft is connected to the trunnion arm 35. 337 is detachably fixed. A speed change operation hole 424 is formed in the right side wall of the clutch housing 10, and the middle of the connecting shaft 337 passes through the speed change operation hole 424. A tip screw portion of the connecting shaft 337 protrudes outward of the clutch housing 10, and a speed change rod 336 is connected to the tip screw portion of the connecting shaft 337 via a connecting nut 425. Therefore, the connecting shaft 337 can be fastened to the trunnion arm 35 by using a tool for inserting the base end side of the connecting shaft 337 into the speed change operation hole 424 from the outside of the clutch housing 10 and screwing the connecting shaft 337.

  As shown in FIGS. 7 and 11, the fulcrum bolt 342 described above is fixed to the clutch housing 10 by welding or the like, and the neutral adjustment body 340 is fitted on the fulcrum bolt 342 protruding outward of the clutch housing 10. The neutral adjustment body 340 is fastened to the fulcrum bolt 342 with a fulcrum nut 426. Therefore, when the fulcrum nut 426 is loosened and the neutral adjustment bolt 343 is loosened, the neutral adjustment body 340 rotates around the fulcrum bolt 342 within the range of the neutral adjustment hole 344, and the circumferential direction around the trunnion shaft 301 Therefore, the speed change limiting hole 345 moves.

  As shown in FIG. 22, the length of the speed change operation hole 424 in the circumferential direction around the trunnion shaft 301 is made longer than the length of the speed limit restriction hole 345 in the circumferential direction around the trunnion shaft 301. Yes. The opening 424 is formed longer than the speed limiting hole 345 at least as long as the neutral adjustment hole 344. By the time the connecting shaft 337 contacts the opening edge of the opening 424, the connecting shaft 337 contacts the opening edge of the speed change limiting hole 345 so that the speed change operation of the trunnion arm 35 is limited.

  As shown in FIGS. 7 and 11, a spring holder 338 is fixed to the outer surface of the clutch housing 10 with a holder bolt 427. An intermediate portion of a spring-type neutral holding spring 339 is wound around the outer periphery of a cylindrical spring holder 338. As shown in FIGS. 11 and 22, the connecting shaft 337 and the locking shaft 341 are clamped by the both ends 339 a and 339 b of the holding spring shape of the neutral holding spring 339. The trunnion arm 35 is configured to be held via a connecting shaft 337 at a shift neutral position determined by the locking shaft 341.

  Next, a description will be given of an operation of adjusting the speed change operation limit range of the continuously variable transmission 25 and the shift neutral position of the continuously variable transmission 25. When the trunnion arm 35 is rotated by stepping on the forward pedal 36 or the reverse pedal 37 with the operator's foot, one of the pinching spring-shaped end portions 339a and 339b of the neutral holding spring 339 is separated from the locking shaft 341 and separated. The end portions 339a and 339b on the other side are pressed against the connecting shaft 337. Therefore, when the foot is released from the forward pedal 36 or the reverse pedal 37, the forward pedal 36 or the reverse pedal 37 returns to the initial position by the biasing force of the neutral holding spring 339, and the forward pedal 36 and the reverse pedal 37 are maintained at the initial position. Further, the trunnion arm 35 returns to the neutral position (position where the shift output is zero) by the urging force of the neutral holding spring 339, and the trunnion arm 35 is held at the neutral position.

  While the forward pedal 36 and the reverse pedal 37 are maintained at the initial positions and the trunnion arm 35 is held at the neutral position, the neutral adjustment bolt 343 and the fulcrum nut 426 are loosened. Further, in a state where the engine 5 is operated, the neutral adjusting body 340 is rotated around the fulcrum bolt 342, and the trunnion arm 35 is rotated via the locking shaft 341, the neutral holding spring 339, and the connecting shaft 337. When the speed change output of the continuously variable transmission 25 (rotation of the main speed change output shaft 67) becomes substantially zero, the neutral adjustment bolt 343 and the fulcrum nut 426 are tightened again, and the neutral adjustment body 340 is fastened to the clutch housing 10. Then, the neutral position adjustment of the trunnion arm 35 is completed. Whether or not the speed change output of the continuously variable transmission 25 has become substantially zero can be determined by whether or not the output rotation speed to the rear wheel 4 has become substantially zero.

  As described above, when the neutral adjustment body 340 is rotated around the fulcrum bolt 342, the shift limiting hole 345 as a stroke stopper for limiting the speed change operation of the trunnion arm 35 moves around the fulcrum bolt 342, and the trunnion arm 35. The shift operation range of the shift to the forward side or the reverse side. Thereby, the range of the speed change operation of the trunnion arm 35 is adjusted. For example, when the shift restriction hole 345 is moved to the forward operation side of the trunnion arm 35, the range of the forward shift operation of the trunnion arm 35 is enlarged, and the range of the reverse shift operation of the trunnion arm 35 is reduced. On the contrary, when the speed change limiting hole 345 is moved to the reverse operation side of the trunnion arm 35, the range of the shift operation on the forward side of the trunnion arm 35 is reduced, and the range of the speed change operation on the reverse side of the trunnion arm 35 is reduced. Enlarged.

  That is, the connecting shaft 337 comes into contact with the opening edge of the speed change limiting hole 345 and the movement of the connecting shaft 337 is restricted. Therefore, the movement on the speed increasing side of the trunnion arm 35 is also restricted, and the maximum speed of the trunnion arm 35 is increased. The position is adjusted. Note that the maximum depression amount of the forward pedal 36 and the reverse pedal 37 (the maximum shift output operation range of the continuously variable transmission 25) is adjusted by adjusting the positions of the forward stopper 323 and the reverse stopper 324 described above. The forward pedal 36 and the reverse pedal 37 are stepped on by the operator as long as the connecting shaft 337 does not contact the opening edge.

  As is clear from the above description and FIGS. 7 and 11, the engine 5 mounted on the traveling machine body 2 including the front wheel 3 and the rear wheel 4 as a traveling unit, and a hydraulic type that shifts power from the engine 5. A continuously variable transmission 25, a transmission case 11 for transmitting a shift output from the hydraulic continuously variable transmission 25 to the front wheels 3 and the rear wheels 4 via a sub transmission gear mechanism 59 as a shift output gear, and a hydraulic continuously variable In a work vehicle including a forward pedal 36 and a reverse pedal 37 as shift pedals connected to a trunnion arm 35 for speed change operation of the transmission 25 via a speed change link mechanism 300, the main body housing of the traveling machine body 2 is provided. A hydraulic continuously variable transmission 25 and a trunnion arm 35 are provided in the clutch housing 10, and one end side of a connecting shaft 337 as a speed change operation body can be attached to and detached from the trunnion arm 35. The other end side of the connecting shaft 337 protrudes outward from the speed change operation hole 424 of the clutch housing 10, and the speed change link mechanism 300 is connected to the other end side of the connecting shaft 337. With the hydraulic continuously variable transmission 25 and the trunnion arm 35 built in the clutch housing 10, the assembling or removing operation of the connecting shaft 337 and the speed change link mechanism 300 can be easily performed. It is possible to improve assembly workability or disassembly workability.

  As apparent from the above description and FIG. 11, the neutral adjustment body 340 for adjusting the neutral position of the trunnion arm 35 is provided, and the neutral adjustment body 340 is disposed on the outer surface of the clutch housing 10. 10, the neutral position of the trunnion arm 35 can be easily adjusted by operating the neutral adjusting body 340, the workability of assembling the connecting shaft 337 and the speed change link mechanism 300, and the workability of adjusting the neutral position of the trunnion arm 35. Can be improved.

  As is apparent from the above description and FIGS. 7, 11, and 22, a neutral holding spring 339 is provided as a pinching spring type spring means for holding the trunnion arm 35 in the neutral position, and the neutral holding spring 339 is held on the outer surface of the clutch housing 10. A spring 339 is arranged, the connecting shaft 337 is held between both ends 339 a and 339 b of the holding spring 339 of the neutral holding spring 339, and both ends 339 a and 339 b of the holding spring 339 of the neutral holding spring 339 are engaged with the neutral adjusting body 340. The neutral holding spring 339 can be compactly installed in the vicinity of the neutral adjusting body 340 because it is configured to come into contact with the locking shaft 341 as a stop portion so as to be able to contact and separate. The trunnion arm 35 can be returned to the neutral position and held by the biasing force of the neutral holding spring 339, and the forward pedal 36 and the reverse pedal 37 can be returned to the initial position and maintained.

  As is clear from the above description and FIGS. 7 and 11, the neutral adjustment body 340 is formed with a speed change limiting hole 345 as a notch hole, penetrates the connecting shaft 337 into the speed change limiting hole 345, and Since the neutral adjustment body 340 is fastened to the intermediate adjustment bolt 343 via the fulcrum bolt 342 and the neutral adjustment bolt 343, the neutral adjustment bolt 343 is loosened around the fulcrum bolt 342 outside the clutch housing 10. Can be rotated. That is, the neutral position of the trunnion arm 35 (position where the shift output is substantially zero) can be easily adjusted outside the clutch housing 10. Further, the speed change limiting hole 345 can be formed so that the connecting shaft 337 can come into contact, and the neutral adjusting body 340 can be used as a stroke stopper for limiting the speed change operation of the trunnion arm 35.

  As is clear from the above description and FIG. 7, one end side of the trunnion arm 35 is fixed to the trunnion shaft 301 of the hydraulic continuously variable transmission 25, and a nut body 423 is fixed to the other end side of the trunnion arm 35. The connecting shaft 337 is formed by processing a base material having a polygonal column shape, and is configured such that one end side of the connecting shaft 337 can be screwed to the nut body 423 from the outside of the clutch housing 10. The forward pedal 36 and the reverse pedal 37 are connected to the trunnion arm 35 in the state where the assembly work of the clutch housing 10 and the hydraulic continuously variable transmission 25 and the like and the assembly work of the forward pedal 36 and the reverse pedal 37 are completed. For this purpose, it is possible to assemble the accessory parts (the connecting shaft 337, the transmission link mechanism 300, the neutral adjustment body 340, etc.) of the speed change operation system of the hydraulic stepless transmission 25 for the hydraulic stepless transmission. It can improve the maintenance workability of the adjustment of the speed change operation system speed machine 25, can and improving the assembly and disassembly operations of such a clutch housing 10 and the forward pedal 36 and reverse pedal 37.

  As is apparent from FIGS. 11 and 22, the engine 5 mounted on the traveling machine body 2 including the front wheels 3 and the rear wheels 4 as the traveling unit, and the hydraulic continuously variable transmission that shifts the power from the engine 5. 25, a transmission case 11 for transmitting a shift output from the hydraulic continuously variable transmission 25 to the front wheels 3 and the rear wheels 4 via a sub transmission gear mechanism 59 as a shift output gear, and a hydraulic continuously variable transmission 25 In a work vehicle including a forward pedal 36 and a reverse pedal 37 as shift pedals connected to a trunnion arm 35 as a shift operation unit via a shift link mechanism 300, the shift output of the hydraulic continuously variable transmission 25 is substantially reduced. The neutral holding function for holding the trunnion arm 35 at the neutral position where the pressure is zero, and the forward pedal 36 and the reverse pedal 37 are maintained at the initial position where the shift output of the hydraulic continuously variable transmission 25 is substantially zero. And a neutral holding spring 339 as a single spring means. The neutral holding spring 339 returns the trunnion arm 35 from the shift output position to the neutral position, and the forward pedal 36 and the reverse pedal. 37 is configured to be returned from the depressed position to the initial position, and therefore, a structure for holding the trunnion arm 35 in the neutral position and a structure for maintaining the forward pedal 36 and the reverse pedal 37 in the initial position. The neutral holding spring 339 can be used for simple configuration, and assembly workability and maintenance workability can be improved.

  As is apparent from FIGS. 11 and 22, the neutral adjustment body 340 is provided as a stroke stopper means for limiting the speed change operation of the trunnion arm 35, and the neutral holding spring 339 for holding the trunnion arm 35 in the neutral position is maintained. Since the limit range of the shift operation of the neutral adjuster 340 can be adjusted in conjunction with the adjustment operation, the shift operation of the trunnion arm 35 can be performed only by adjusting the trunnion arm 35 in the neutral position. Can be adjusted and maintenance workability can be improved.

  As is apparent from FIGS. 7, 11, and 22, a shift operation portion is formed by the trunnion arm 35 for changing the output of the hydraulic pump 63 of the hydraulic continuously variable transmission 25, and the neutral adjustment pin is provided on the trunnion arm 35. Are connected to one end side of the connecting shaft 337, and the speed change link mechanism 300 is connected to the other end side of the connecting shaft 337. The holding spring of the neutral holding spring 339 is connected to the intermediate portion of the connecting shaft 337 and the neutral adjusting body 340. Since both ends 339a and 339b of the shape are connected, the neutral adjusting body 340 and the neutral holding spring 339 can be easily assembled in a compact installation space. Since the connecting shaft 337 can be formed by cutting a hexagonal column-shaped base material, the base end side of the connecting shaft 337 is inserted into the clutch housing 10 from the outside of the clutch housing 10 via the speed change operation hole 424. The proximal end side of the connecting shaft 337 can be screwed to the trunnion arm 35, and the other end side of the connecting shaft 337 can be projected outward of the clutch housing 10. That is, after assembling heavy parts such as the clutch housing 10 and the hydraulic continuously variable transmission 25 (main parts of the traveling machine body 2), the speed change operation mechanisms such as the speed change link mechanism 300 and the connecting shaft 337 (accessory parts lighter than the main parts). ) Can be assembled by retrofitting.

  As is clear from the above description and FIGS. 11 and 22, the neutral adjustment body 340 is formed with a speed change limiting hole 345 as a notch hole, and the connecting speed shaft 337 penetrates the speed change limiting hole 345. Therefore, the movement of the connecting shaft 337 can be restricted by the speed change restriction hole 345, and the stroke stopper mechanism for restricting the speed change operation of the trunnion arm 35 can be simply configured by the neutral adjustment body 340, and the assembly workability and the like can be improved. The neutral adjustment body 340 can be formed with low rigidity and high rigidity by cutting a substantially triangular flat iron plate.

  As is clear from FIGS. 11 and 22, the neutral adjustment body 340 is fastened to the traveling machine body 2 via the fulcrum bolt 342 and the neutral adjustment bolt 343, and the neutral adjustment is performed in the long neutral neutral adjustment hole 344 of the neutral adjustment body 340. Since the neutral position of the trunnion arm 35 can be adjusted by an operation of passing the bolt 343, loosening the neutral adjustment bolt 343, and rotating the neutral adjustment body 340 around the fulcrum bolt 342, the engine 5 While the hydraulic continuously variable transmission 25 is driven by the output of, the neutral adjusting bolt 343 is loosened and the neutral adjusting body 340 is rotated around the fulcrum bolt 342, so that the output rotational speed of the hydraulic continuously variable transmission 25 is increased. By tightening the neutral adjustment bolt 343 at the substantially zero position and fastening the neutral adjustment body 340 to the clutch housing 10 of the traveling machine body 2, The adjustment work for holding the arm 35 in the neutral position for shifting and the adjustment work for changing the limit range of the shifting operation of the neutral adjusting body 340 can be easily performed outside the clutch housing 10, so that assembly workability and maintenance can be performed. Workability etc. can be improved.

It is the whole tractor side view. It is a top view of the traveling body of a tractor. It is an enlarged plan view of the latter half part of the traveling machine body. It is an enlarged plan view of the peripheral part of the step frame of the traveling machine body. It is a perspective view of the pedal etc. which an operator operates. It is a section side view of a mission case and a mission front case. It is front explanatory drawing of a mission front case. It is a hydraulic circuit diagram. It is side explanatory drawing, such as a forward pedal, a reverse pedal, and a speed change link mechanism. It is side surface explanatory drawing, such as a forward pedal and a reverse pedal. FIG. 10 is an enlarged side view of the transmission link mechanism and the like of FIG. 9. It is expansion side explanatory drawing, such as a forward pedal and a reverse pedal of FIG. It is plane explanatory drawings, such as a forward pedal and a reverse pedal. FIG. 14 is an enlarged plan view of the forward pedal and the reverse pedal of FIG. 13. It is a side view explaining operation of a cruise lever or the like. It is side surface explanatory drawings, such as a brake pedal and a parking brake lever. It is the elements on larger scale of FIG. It is side surface explanatory drawing of a brake pedal attachment part. It is plane explanatory drawings, such as a brake pedal and a parking brake lever. It is the elements on larger scale of FIG. It is front explanatory drawing, such as a brake pedal and a parking brake lever. It is the elements on larger scale of FIG.

Explanation of symbols

2 traveling body 3 front wheel (traveling part)
4 Rear wheels (traveling part)
5 Engine 11 Mission case 25 Hydraulic continuously variable transmission 35 Trunnion arm 36 Forward pedal (shift pedal)
37 Reverse pedal (shift pedal)
59 Sub-transmission gear mechanism (shift output gear)
300 Transmission link mechanism 301 Trunnion shaft 337 Connection shaft (transmission operation body)
339 Neutral holding spring (spring means)
340 Neutral adjustment body 341 Locking shaft (locking part)
342 Support bolt 343 Neutral adjustment bolt 344 Neutral adjustment hole 345 Speed limit hole (notch hole)
423 Nut body 424 Shifting operation hole

Claims (5)

An engine mounted on a traveling machine body having a traveling unit, a hydraulic continuously variable transmission that shifts power from the engine, and a shift from the hydraulic continuously variable transmission to the traveling unit via a transmission output gear In a work vehicle comprising a transmission case for transmitting an output, and a speed change pedal connected to a trunnion arm for speed change operation of the hydraulic continuously variable transmission via a speed change link mechanism,
The hydraulic continuously variable transmission and the trunnion arm are installed in the main unit housing of the traveling machine body,
One end side of the speed change operation body is detachably fixed to the trunnion arm, the other end side of the speed change operation body protrudes outward from the speed change operation hole of the machine housing, and the other end side of the speed change operation body A work vehicle characterized in that the shift link mechanism is connected to the vehicle.   The work vehicle according to claim 1, further comprising a neutral adjustment body that adjusts a neutral position of the trunnion arm, wherein the neutral adjustment body is disposed on an outer surface of the machine housing.   A spring means of a pinch spring type that holds the trunnion arm in a neutral position is provided, the spring means is arranged on the outer surface of the housing of the machine, and the speed change operation body is pinched by both ends of the pinch spring type of the spring means. The work vehicle according to claim 2, wherein both end portions of the sandwiching spring shape of the spring means are configured to come into contact with and separable from the locking portion of the neutral adjustment body.   A notch hole is formed in the neutral adjusting body, the speed change operating body is passed through the notch hole, and the neutral adjusting body is fastened to the outer surface of the machine housing via a fulcrum bolt and an adjusting bolt. The work vehicle according to claim 4. One end side of the trunnion arm is fixed to the trunnion shaft of the hydraulic continuously variable transmission, and a nut body is fixed to the other end side of the trunnion arm. The work vehicle according to claim 4, wherein the work vehicle is configured so that one end side of the speed change operation body can be screwed to the nut body from the outside of the machine housing.

Images