JP4860410B2 - Work vehicle - Google Patents

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. More specifically, the present invention relates to a mid PTO shaft that transmits power from the engine to a mower working machine, and a mid PTO shaft. The present invention relates to a work vehicle having a mid PTO brake for braking.

  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 traveling case is provided with a transmission case, a mid PTO shaft projects forward from the transmission case, and power is transmitted from the mid PTO shaft to a mower working machine below the traveling body. In the structure, a traveling machine body equipped with an engine, a transmission case that transmits power from the engine via a clutch mechanism, a PTO shaft that transmits power from the engine to a work machine mounted on the traveling machine body, and a PTO that brakes the PTO shaft The brake is equipped with a PTO brake operation shaft on the side of the transmission case, and the PTO brake operation shaft is connected to the PTO brake. The brake operation link is extended upward from the PTO brake operation shaft. A clutch pedal is connected to the upper end side of the operation link via a pedal connection mechanism, and the clutch The PTO brake is braked by the dull cutting operation, and the power transmitted from the engine to the PTO shaft is cut only by the clutch pedal cutting operation, and at the same time, the inertial rotation of the mowing blade of the mower working machine is prevented ( For example, see Patent Document 1).
Japanese Patent Laid-Open No. 2-81718

  In the above prior art, there is a limit to the length of the brake operation link extending in the direction of the upper step, and the lever action of the brake operation link cannot be used. Therefore, the stepping operation force of the clutch pedal to which the operation force of the PTO brake is applied can be simplified. There is a problem that it cannot be reduced. For example, when the PTO brake operation shaft and the clutch pedal are arranged apart from each other, the conventional technology in which the pedal coupling mechanism is formed of a single component has a problem that the coupling rigidity of the pedal coupling mechanism cannot be easily secured. On the other hand, in the prior art in which the pedal coupling mechanism is arranged at a high position on the outer side of the transmission case, when the transmission output switching lever is assembled on the outer side of the transmission case, the assembly position of the transmission output switching lever is the pedal coupling mechanism. Or the mounting position of the pedal coupling mechanism is limited by the shift output switching lever. For example, the grip portion of the shift output switching lever protrudes greatly on the step side where the operator gets on and off, and the grip portion of the shift output switching lever However, there are problems such as getting in the way of getting on and off the operator.

  An object of the present invention is to provide a work vehicle that can easily prevent inertial rotation of a work machine by stepping on a clutch pedal while easily reducing the stepping force of the clutch pedal.

In order to achieve the above object, a work vehicle according to a first aspect of the present invention includes an engine mounted on a traveling machine body, a transmission case that transmits power from the engine through a clutch mechanism, and a work connected to the traveling machine body. A PTO shaft that transmits power from the engine to the machine and a PTO brake that brakes the PTO shaft. A brake operation intermediate shaft is disposed on a side surface of the transmission case, and the PTO brake is connected to the brake operation intermediate shaft. In a work vehicle configured to brake the PTO brake by operating a clutch pedal for operating the clutch mechanism, a brake operation link is extended downward from the brake operation intermediate shaft. The clutch pedal is coupled to the lower end side of the brake operation link via a pedal coupling mechanism. And along a lower end of one side outside of the transmission case, placing the pedal coupling mechanism, the pedal coupling mechanism includes a front rod connected to the clutch pedal, is connected to the lower end side of the brake operating link A shift output switching shaft having a rear rod and projecting from the side surface of the transmission case is rotatably fitted with an arm body for connecting the front rod and the rear rod .

According to a second aspect of the present invention, in the work vehicle according to the first aspect , the shift output switching unit is provided with a shift output switching lever that extends in a vertical direction outside the transmission case and is supported by the shift output switching shaft. The front rod is disposed on the outer side of the lever.

According to a third aspect of the present invention, in the work vehicle according to the second aspect , a grip portion of the shift output switching lever is disposed above a boarding / alighting step for an operator to get on and off the control seat of the traveling body. The pedal coupling mechanism such as the front rod is disposed below the getting-on / off step.

  According to the first aspect of the present invention, the engine mounted on the traveling machine body, the transmission case that transmits the power from the engine via the clutch mechanism, and the working machine connected to the traveling machine body receive the power from the engine. A transmission PTO shaft and a PTO brake that brakes the PTO shaft are arranged. A brake operation intermediate shaft is arranged on a side surface of the transmission case, the PTO brake is connected to the brake operation intermediate shaft, and the clutch mechanism is turned off. A work vehicle configured to brake the PTO brake by a clutch pedal disengagement operation for extending a brake operation link downward from the brake operation intermediate shaft, and a lower end side of the brake operation link The clutch pedal is connected to the side of the transmission case via a pedal connection mechanism. Since the pedal coupling mechanism is arranged along the lower end side of the other side, the brake operation link can be formed to a length that can reduce the pedal force of the clutch pedal by utilizing the lever action. It is possible to easily reduce the stepping operation force of the clutch pedal to which the brake operation force for preventing inertial rotation of the machine is added. Further, for example, the pedal coupling mechanism can be easily assembled to the lower end of the outer side of the transmission case without being restricted by a shift output switching lever or the like. The workability such as can be improved.

In addition, the pedal coupling mechanism includes a front rod coupled to the clutch pedal and a rear rod coupled to the lower end side of the brake operation link, and a shift output switching shaft protruding from a side surface of the transmission case. Since the arm body for connecting the front rod and the rear rod is rotatably fitted, for example, the brake operation intermediate shaft and the clutch pedal are arranged apart from each other. However, the pedal connection mechanism can be divided into a plurality of parts across the shift output switching shaft, and the connection rigidity of the pedal connection mechanism can be easily secured. Further, since it is not necessary to specially install a support shaft and a bearing for incorporating the pedal coupling mechanism, a traveling machine body such as the transmission case for arranging the pedal coupling mechanism can be easily formed.

According to the second aspect of the present invention, the shift output switching lever that extends in the vertical direction on the outer side of the transmission case is provided, and the front rod is disposed on the outer side of the shift output switching lever supported by the shift output switching shaft. Since it is arranged, the shift output switching lever can be formed without being restricted by the pedal coupling mechanism such as the front rod, and the shift output switching lever is compactly assembled along the side surface of the mission case. be able to. In addition, the pedal connecting mechanism such as the front rod can be easily assembled by changing only the length of the shift output switching shaft in the axial direction and hardly changing the support structure of the shift output switching lever. It is something that can be done.

According to the invention of claim 3 , the grip portion of the shift output switching lever is disposed above the getting-on / off step for an operator to get on and off the control seat of the traveling body, and the front rod or the like is below the getting-on / off step. Therefore, the assembly of the shift output switching lever and the assembly of the pedal connection mechanism are not restricted to each other, and the shift output switching lever and the pedal connection mechanism are not limited to each other. Assembly workability can be improved. For example, the shift output switching lever grip can be configured so that it hardly protrudes in the operator's boarding space on the upper surface side of the step, and the shift output switching lever grip can be compactly arranged at a position that does not interfere with the operator It is.

  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 right side view of the entire tractor, FIG. 2 is a plan view of the entire tractor, FIG. 3 is a perspective view of the traveling aircraft, FIG. 4 is a plan view of pedals and the like operated by the operator, and FIG. FIG. 6 is a side view of the front part of the traveling machine body, FIG. 7 is a perspective view of the front part of the traveling machine body, FIG. 8 is a side view of the forward pedal, the reverse pedal, the transmission link mechanism, and the like. 9 is an enlarged side view of the forward pedal and the reverse pedal of FIG. 8, FIG. 10 is a plan view of the forward pedal and the reverse pedal, etc. FIG. 11 is a side view of the operation of the cruise lever and the like, and FIG. FIG. 13 is an explanatory side view of a brake pedal and the like, FIG. 14 is an enlarged side view of FIG. 13, and FIG. 15 is an enlarged perspective view of FIG.

  As shown in FIGS. 1 to 3, 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 step floor plates 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. Further, a lops frame 2 a is erected on the traveling machine body 2 behind the control seat 17.

  On the upper surface of the transmission case 11, a hydraulic working machine lifting mechanism 20 for lifting and lowering a crushing working machine 19 such as a wood chipper connected to the rear part of the traveling machine body 2 is detachably attached. Further, a rear 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 that protrudes rearward from the main clutch 9, and then the output from the continuously variable transmission 25 is transmitted to the auxiliary transmission gear mechanism in the transmission case 11. The speed is appropriately changed at 27 and transmitted to both the rear wheels 4 and the front wheels 3. On the other hand, a mid PTO shaft 28 protruding forward is disposed at the bottom of the mission case 11. The rotation of the engine 5 from the main drive shaft 26 is transmitted to the rear PTO shaft 21 and the mid PTO shaft 28. That is, the crushing work machine 19 or the rotary work machine (not shown) arranged behind the traveling machine body 2 is driven via the rear PTO shaft 21. Further, a mower working machine 29 for lawn mowing disposed below the traveling machine body 2 between the front wheel 3 and the rear wheel 4 is driven via the mid PTO shaft 28.

  Next, with reference to FIGS. 3 to 5, the structure of the control unit operated by the operator of the control seat 17 will be described. 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. The clutch pedal 31 is connected to a clutch disengaging mechanism 39 that disengages the main clutch 9 and a clutch-containing spring 9b that maintains the clutch pedal 31 in the initial position, and the clutch pedal 31 is maintained in the initial position by the clutch-containing spring 9b. Will be. A clutch operating shaft 39a 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 39a. 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 30 which will be described later, and the clutch pedal 31 is connected to the clutch operation shaft 39a via the clutch operation link mechanism 40. (See FIG. 5). By depressing the clutch pedal 31, the main clutch 9 is disengaged. The clutch operation link mechanism 40 includes a first clutch link 40a fixed to the boss portion 31b, a second clutch link 40b fixed to the clutch operation shaft 39a, and a clutch rod 40c connected to the links 40a and 40b. 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. The brake pedal 33 is connected with a left and right rear wheel braking brake mechanism 32 via left and right brake rods 32a. Accordingly, the brake mechanism 32 is operated by the operation of the brake pedal 33, and the left and right rear wheels 4 are braked. Further, the brake pedal 33 is maintained at 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 removes his / her foot from the brake pedal 33. A brake operation bearing portion 10a is integrally formed at the bottom of the clutch housing 10 by casting. A brake operation shaft 30 is pivotally supported on the brake operation bearing portion 10a (see FIG. 8). The left and right brake rods 32a are connected to the brake pedal 33 via the brake operation shaft 30 (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 (see FIG. 3). A trunnion arm 35 is connected to the forward pedal 36 and the reverse pedal 37 via a speed change link mechanism 41, 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 can move forward or reverse. A shifting operation is performed.

  An accelerator lever 42 for adjusting the rotational speed of the engine 5 is disposed on the right side of the steering column 15 (see FIG. 2). In addition, a parking brake lever 34 and a cruise lever 38 are disposed below the steering handle 16 and on the back surface of the steering column 15 where the operator's feet sitting on the steering seat 17 are difficult to hit. On the other hand, on the left side of the control seat 17, there are arranged a sub transmission operation lever 43 for switching the sub transmission gear mechanism 27 and a mid PTO clutch lever 44 for operating the mid PTO shaft 28 (see FIG. 2). On the right side of the control seat 17, an elevating operation lever 45 that operates the working machine elevating mechanism 20 and a rear PTO clutch lever 46 that operates the rear PTO shaft 21 are arranged (see FIG. 2).

  Next, the structure of the front part of the traveling machine body 2 such as the engine 5, the bonnet 14, and the steering column 15 will be described with reference to FIGS. As shown in FIGS. 6 and 7, a radiator 47, an air cleaner 48, a battery 49, and the like are arranged on the upper side of the engine frame 8 in front of the engine 5 via an engine room front side frame 50. A front blocking plate 51 is extended to the left and right and above the radiator 47, and a gap formed between the bonnet 14 and the radiator 47 is blocked by the front blocking plate 51. The bonnet 14 includes an upper bonnet 14a, left and right side bonnets 14b, and a front bonnet 14c. Outside air is sucked by the cooling fan 52 in front of the engine 5 in the direction of the engine 5 from the front surface of the radiator 47 through the front bonnet 14c forming a front grille that can be ventilated.

  As shown in FIG. 6, the upper bonnet 14a and the front bonnet 14c are integrally connected via a hood front frame 53 and the like. An engine room 54 in which the engine 5 is installed is formed between the front blocking plate 51 and the rear blocking plate 55. A rear-side shielding plate 55 is erected along the rear surface of the engine 5, the rear side of the engine 5 is blocked by the rear-side shielding plate 55, the engine room 54 is opened downward, and the outside air drawn in by the cooling fan 52 is removed. It is discharged below the engine 5.

  A handle post 57 is erected on the upper surface of the clutch housing 10 behind the rear blocking plate 55 via a handle frame 56, and the steering handle 16 is assembled to the upper end of the handle post 57 (see FIG. 6). . A tank frame 58 is connected to the upper surface side of the handle frame 56 and the upper end side of the rear shielding plate 55, and the fuel tank 59 is detachably attached to the tank frame 58. The steering column 15 includes a tank cover 60, a post cover 61, and a meter panel box 62. A fuel tank 59 for supplying fuel to the engine 5 is disposed in the tank cover 60. An oil cap 64 is disposed on the upper surface of the tank cover 60 via an oil tray 63 (see FIG. 7). The fuel cap 64 is removed and the fuel tank 59 is refilled with fuel.

  Note that the left and right and the rear of the handle post 57 are covered with the post cover 61. A meter panel box 62 is arranged on the upper surface side of the tank cover 60 and the post cover 61.

  As shown in FIG. 6, the bonnet fulcrum frame 65 is disposed at the connecting portion between the tank frame 58 and the rear blocking plate 55. A bonnet support frame 67 is rotatably connected to the bonnet fulcrum frame 65 via a bonnet opening / closing fulcrum shaft 66. The inner surface of the rear part of the upper bonnet 14 a is fixed to the bonnet support frame 67. Strut links 69 and 70 are connected to a bonnet stand 68 disposed on the upper surface of the engine 5 and a bonnet support frame 67. By lifting the upper bonnet 14a and the front bonnet 14c upward, the tension links 69 and 70 are deployed, supported at the positions where the upper bonnet 14a and the front bonnet 14c are opened, and on the upper side and front of the engine room 54 Will be released.

  As shown in FIG. 7, a U-shaped bonnet hook 71 is fixed to the lower end side of the bonnet front frame 53. A bonnet lock mechanism 73 having a release lever 72 is disposed on the engine frame 8. The bonnet hook 71 is locked to the engine frame 8 through the bonnet lock mechanism 73, and the upper bonnet 14a and the front bonnet 14c are supported in the closed position. By operating the release lever 72 and releasing the bonnet hook 71 from the bonnet lock mechanism 73, the upper bonnet 14a and the front bonnet 14c can be moved to the open position.

  Further, as shown in FIG. 7, the rear end side of the laterally V-shaped pressure receiving plate 74 is fixed to the engine room front side frame 50, and the pressure receiving plate 74 projects forward from the engine room front side frame 50. On the front end side of the pressure receiving plate 74, a closed support guide notch 75 having a V-shape in a plan view that is wide at the front is formed. When the upper bonnet 14 a and the front bonnet 14 c move from the open position to the close position, the bonnet front frame 53 is fitted into the close support guide notch 75 immediately before the bonnet hook 71 is locked to the bonnet lock mechanism 73. The bonnet front frame 53 is engaged with the pressure receiving plate 74 via the closed support guide notch 75, the bonnet front frame 53 is positioned and supported by the pressure receiving plate 74, and the upper bonnet 14a and the front bonnet 14c are closed. Will be moved to.

  That is, the engagement between the closed support guide notch 75 and the bonnet front frame 53 corrects the lateral displacement of the bonnet hook 71 with respect to the bonnet lock mechanism 73. Therefore, the upper bonnet 14a and the front bonnet 14c are The bonnet hook 71 is locked to the bonnet lock mechanism 73 only by the operation of moving from the open position to the close position. The upper bonnet 14a and the front bonnet 14c can be easily moved from the open position to the closed position.

  In the state where the upper bonnet 14a and the front bonnet 14c are locked in the closed position, the left and right sides of the upper bonnet 14a and the front bonnet 14c are engaged by the engagement of the closed support guide notch 75 and the bonnet front frame 53. Since movement in the direction (lateral movement) is prevented, the spring force of the bonnet lock mechanism 73 for retaining and maintaining the bonnet hook 71 can be reduced, and the release lever 72 can be easily operated with a small force.

  Next, the drive structure of the front wheel 3 will be described with reference to FIG. In the transmission front case 12 described above, a four-wheel drive switching mechanism 76 that transmits driving force from the auxiliary transmission gear mechanism 27 to the front wheels 3 is provided. The four-wheel drive switching mechanism 76 has a front wheel drive gear (not shown), a front wheel output clutch, and a front wheel output shaft. By turning on and operating the front wheel output clutch of the four-wheel drive switching mechanism 76, the output rotation of the auxiliary transmission gear mechanism 27 is transmitted from the four-wheel drive switching mechanism 76 to the front wheel transmission shaft 77, and from the front wheel transmission shaft 77. It is transmitted to the front axle case 7, transmitted from the front axle case 7 to the front wheel 3, and the front wheel 3 is driven. That is, the tractor 1 moves in a four-wheel drive state in which the left and right front wheels 3 and the left and right rear wheels 4 are driven.

  As shown in FIGS. 16 and 17, the four-wheel drive switching operation shaft 78 for turning on and off the front wheel output clutch of the four-wheel drive switching mechanism 76 is located outwardly on the left side of the transmission front case 12 in the forward direction. It is protruding. The base end portion of the four-wheel drive switching operation lever 79 is connected to the left end of the four-wheel drive switching operation shaft 78 projecting outward from the left side of the mission front case 12. Therefore, by rotating the 4WD switching operation lever 79 around the 4WD switching operation shaft 78, the front wheel output clutch of the 4WD switching mechanism 76 is engaged or disengaged. Note that by operating the front wheel output clutch of the four-wheel drive switching mechanism 76, the driving of the front wheels 3 is stopped, and the tractor 1 moves in a two-wheel drive state in which the left and right rear wheels 4 are driven.

  Next, with reference to FIGS. 8 to 11, the mounting structure of the forward pedal 36 and the reverse pedal 37 will be described. As shown in FIGS. 8 and 11, the base frame 90 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 91. A vertical plate 94 is integrally fixed to the base frame 90 by welding via front and rear horizontal plates 92 and 93.

  That is, the pedal unit frame 89 that is rectangular in plan view for assembling the forward pedal 36 and the reverse pedal 37 is formed of the base frame 90, the front and rear side plates 92 and 93, and the vertical side plate 94. The pedal unit frame 89 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 FIG. 10, the base frame 90 and the vertical side plate 94 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. A forward pedal shaft 95 and a reverse pedal shaft 96 are rotatably supported on the base frame 90 and the vertical side plate 94, and the forward pedal shaft 95 and the reverse pedal shaft 96 are arranged between the front and rear lateral plates 92 and 93. One end side of the forward pedal shaft 95 and the reverse pedal shaft 96 protrudes outward of the vertical side plate 94. A boss 98 on the base end side of the pedal arm 97 of the forward pedal 36 is fitted on one end side of the forward pedal shaft 95 on the outer side of the vertical side plate 94. Further, the boss portion 100 on the base end side of the pedal arm 99 of the reverse pedal 37 is fitted on one end side of the reverse pedal shaft 96 on the outer side of the vertical side plate 94.

  Therefore, the forward pedal 36 and the reverse pedal 37 are disposed so as to be rotatable around the axis of the forward pedal shaft 95 and the reverse pedal shaft 96. The pedal arm 97 of the forward pedal 36 and the pedal arm 99 of the reverse pedal 37 are projected obliquely forward and upward from the forward pedal shaft 95 and the reverse pedal shaft 96, and the reverse 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 FIG. 9, stop arms 101 and 102 are fixed to the boss portion 98 of the forward pedal shaft 95 and the boss portion 100 of the reverse pedal shaft 96. Bolt-shaped forward stoppers 103 and reverse stoppers 104 for bringing the stop arms 101 and 102 into contact with each other are disposed on the outer surface of the vertical side plate 94. The forward stopper 103 and the backward stopper 104 are screwed to the stopper receiving bracket 105 fixed to the vertical side plate 94 by welding so that the positions of the forward stopper 103 and the backward stopper 104 can be adjusted. Accordingly, the stop arms 101 and 102 come into contact with the forward stopper 103 and the reverse stopper 104, 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 103. And the reverse stopper 104 is set.

  As shown in FIGS. 9 and 10, the base end portion of the pressing arm 106 is fixed to the forward pedal shaft 95, and the abutting roller 108 is rotatable at the distal end portion of the pressing arm 106 via the roller shaft 107. Pivot. Further, the base end portion of the swing arm 109 is fixed to the reverse pedal shaft 96. A pressure receiving piece 110 and a locking piece 111 are integrally formed on the swing arm 109. A pressure receiving piece 110 is brought into contact with the contact roller 108, and a tension spring 112 is connected to the roller shaft 107 and the locking piece 111. Therefore, the contact roller 108 and the pressure receiving piece 110 always come into contact with each other by the spring force of the tension spring 112.

  Further, as shown in FIGS. 9 and 10, the base end portion of the transmission arm 113 is fixed to the reverse pedal shaft 96, and the distal end portion of the transmission arm 113 is expanded and contracted via the connecting pin 114 and the joint bracket 115. One end of the adjustable speed change rod 116 is connected. The other end side of the speed change rod 116 is connected to the above-described trunnion arm 35 via a connecting shaft 117.

  Further, a neutral holding spring 119 sandwiched between the clutch housing 10 via a spring holder 118 is disposed. A locking shaft 121 is fixed to the clutch housing 10 via a neutral adjusting body 120. Both ends of the neutral holding spring 119 are locked to the connecting shaft 117 and the locking shaft 121. The neutral adjustment body 120 is fixed to the clutch housing 10 by one fulcrum bolt 122 for neutral adjustment and two neutral adjustment bolts 123. The neutral adjustment bolt 123 is passed through the long hole-type neutral adjustment hole 124 of the neutral adjustment body 120. A shift regulation hole 125 is formed in the neutral adjustment body 120, and the connecting shaft 117 is passed through the long hole-type shift regulation hole 125.

  As shown in FIG. 9, the transmission restriction hole 125 is formed long in the circumferential direction around the trunnion shaft 88 provided with the trunnion arm 35. Therefore, the lower end side of the trunnion arm 35 that hangs substantially vertically downward from the trunnion shaft 88 around the trunnion shaft 88 in the continuously variable speed range in which the connecting shaft 117 moves in the speed change restriction hole 125 is the forward side ( It will rotate backwards or backward (forward).

  On the other hand, the neutral adjustment hole 124 of the neutral adjustment body 120 is formed long in the circumferential direction around the fulcrum bolt 122. Accordingly, the neutral adjustment bolt 123 is loosened, the neutral adjustment body 120 is rotated around the fulcrum bolt 122, the locking shaft 121 is moved to adjust the neutral (output zero) position, and the shift restriction hole 125 is By moving, the continuously variable transmission range of the connecting shaft 117 is adjusted.

  As shown in FIGS. 9 and 10, the base end portion of the pedaling force adjusting link 126 is fixed to the forward pedal shaft 95. One end side of the pedal force frame 129 is connected to one of a plurality of pedal force adjustment holes 127 formed in the pedal force adjustment link 126 via a pedal force adjustment pin 128. In addition, the base end portion of the connection link 131 and the base end portion of the treading force link 132 are fixed to the rotatable cylindrical shaft body 130 on the brake operation shaft 30 described above. The distal end portion of the connection link 131 is connected to the other end side of the pedaling force frame 129 via a connection pin 133. A pedal force damper 135 is connected to the tip of the pedal force link 132 via a support pin 134. The pedal force damper 135 is assembled to the outer side of the clutch housing 10 via a damper mounting shaft 136 (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 106 is rotated around the forward pedal shaft 95 and the swing arm 109 is moved by the contact roller 108 to the reverse pedal shaft. Rotate around 96. The transmission arm 113 on the reverse pedal shaft 96 is rotated by the rotation of the swing arm 109, the transmission rod 116 is pushed by the transmission arm 113, and the trunnion arm 35 and the trunnion shaft 88 against the neutral holding spring 119 force. Rotates in the forward direction (clockwise in FIG. 9), operates the continuously variable transmission 25 forward, drives the front wheels 3 and the rear wheels 4 forward, 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 until the stop arm 101 comes into contact with the forward stopper 103 or the connecting shaft 117 is controlled to change speed. 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 125. Further, when the forward pedal 36 is stepped on and the swing arm 109 is rotated, the reverse pedal 37 is rotated around the reverse pedal shaft 96 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 speed change arm 113 on the reverse pedal shaft 96 is rotated via the swing arm 109 and the speed change arm 113 changes the speed change rod. 116 is pulled, and the trunnion arm 35 and the trunnion shaft 88 are rotated in the reverse direction (counterclockwise in FIG. 9) against the force of the neutral holding spring 119, 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 102 comes into contact with the reverse stopper 104 or the connecting shaft 117 is controlled to change speed. The reverse pedal 37 can be depressed to increase the reverse speed until it contacts the other end of the hole 125. Further, when the reverse pedal 37 is depressed, the pressing arm 106 is rotated via the contact roller 108 by the rotation of the swing arm 109, and the forward pedal 36 is moved in the direction opposite to the stepping operation direction. It is rotated around 95.

  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) by the regulation of the pedal force damper 135 by the neutral holding spring 119 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 141 includes a plurality of locking claws 142 and a single locking body 143 that are detachably engaged. The locking body 143 and the locking claw 142 are disposed so as to face each other so as to be able to contact and separate.

  As shown in FIG. 8, one end side of the clutch operating shaft 39a protrudes 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 appears at the protruding end of the clutch operating shaft 39a. The middle of the locking link 144 is pivotally supported, one end side of the locking link 144 is connected to the cruise lever 38 as a manual operation lever, and the other end side of the locking link 144 is a protrusion-type engagement. The stop body 143 is integrally formed.

  As shown in FIG. 11, one end side of a locking arm 145 having an arcuate side view is connected to the forward pedal shaft 95, and a plurality of locking claws 142 are continuously provided on the outer peripheral edge of the other end side of the locking arm 145. Form. The direction in which the locking body 143 is engaged with or disengaged from the locking claw 142 is made substantially orthogonal to the tangential line of the circumferential trajectory in which the locking arm 145 rotates by the neutral holding spring 119. The engaging surfaces of the locking claw 142 and the locking body 143 are substantially orthogonal to the tangential line of the circular locus on which the locking arm 145 rotates. Therefore, when the forward pedal 36 is further depressed in the speed increasing direction, the locking body 143 is disengaged by the speed increasing side locking claw 142 adjacent to the locking claw 142 engaged with the locking body 143. The engagement between the locking claw 142 and the locking body 143 is released.

  That is, the shape of the locking claw 142 and the locking body 143 is such that the rotational moment that the locking arm 145 rotates by the neutral holding spring 119 acts as a force for engaging the locking body 143 with the locking claw 142. Form. The turning force (neutral holding spring 119 force) of the locking arm 145 that engages the locking body 143 with the locking claw 142 is the force of the cutting holding spring 146 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 143 from the locking claw 142) 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 145 is configured to return to the initial position by the neutral holding spring 119.

  Therefore, the locking body 143 is not detached from the locking claw 142 by the force that returns the cruise lever 38 to the cutting position by the cutting holding spring 146. Further, the locking body 143 is not detached from the locking claw 142 by the pushing operation force that the operator returns the cruise lever 38 from the vehicle speed maintaining position (entering position) to the cutting position. The rotational moment that the locking arm 145 is rotated by the neutral holding spring 119 acts as an engaging force on the locking claw 142 and the locking body 143, 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 142 and the locking body 143 can be maintained by a neutral holding spring 119 force as an initial position return spring for this purpose.

  Next, the vehicle speed maintaining operation (auto cruise operation) of the vehicle speed maintaining mechanism (auto cruise mechanism) 141 described above will be described with reference to FIGS. When the cruise lever 38 is pulled up against the holding spring 146 by the operator while the forward pedal 36 is depressed by the operator, the locking link 144 is moved from the virtual line position to the solid line position as shown in FIG. It rotates around the clutch operating shaft 39a, and the locking body 143 is engaged with the locking claw 142. 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 stepped on by the operator in a state in which the locking body 143 is engaged with the locking claw 142, the locking body 143 is released from the locking claw 142, and the cruise lever 38 and the engagement lever are engaged. The stop link 144 is cut from the solid line position to the virtual line position (initial position) and returned by the holding spring 146, and the vehicle speed holding operation (auto cruise operation) that moves at a substantially constant speed is released.

  Next, with reference to FIGS. 5 and 11 to 15, a mounting structure of the brake pedal 33 and the like as the brake operation means will be described. As shown in FIGS. 5, 11, and 12, the brake pedal shaft 151 is detachably fixed to the left and right bearing brackets 150 of the step frame 13 described above. The left and right bearing brackets 150 extend substantially parallel to the front-rear direction of the traveling machine body 2. A boss 153 on the base end side of the pedal arm 152 of the brake pedal 33 is fitted between the left and right bearing brackets 150 via the brake pedal shaft 151. A fastening plate 155 on the right end side of the brake pedal shaft 151 is fastened to the right bearing bracket 150 from the outside of the traveling machine body 2 via a bolt 154. The brake pedal 33 is removed from the step frame 13 by removing the bolt 154 and extracting the brake pedal shaft 151 to the outside of the bearing bracket 150.

  As shown in FIGS. 5, 11, and 12, the boss portion 153 of the pedal arm 152 is coupled to the pedal operation shaft 30 described above via the brake link mechanism 161. The brake link mechanism 161 includes one brake arm 156 fixed to the pedal operation shaft 30 via the arm boss portion 162, the other brake arm 157 fixed to the boss portion 153, and a pin 158 to each brake arm 156, 157. , 159, and a brake link 160 connected thereto. The brake rod 32 a is connected to the arm boss portion 162 via the rod arm 163. Further, the hook arm 164 and the rod arm 163 of the vertical side plate 94 are connected by a brake release spring 165. The brake pedal 33 is maintained at the initial position by the brake release spring 165, and the braking operation of the brake mechanism 32 is held in a state released by the brake release spring 165.

  A parking brake structure that maintains the brake pedal 33 in the depressed position will be described with reference to FIGS. 13 to 15. As shown in FIG. 14, the base end side of the lock arm 166 is fixed to the boss portion 153 of the pedal arm 152, and the locking projection 167 is integrally formed on the distal end side of the lock arm 166. Further, the rear end side of the fulcrum frame 168 is fixed to the front side of the step frame 13 described above, the arm support shaft 169 is disposed on the front end side of the fulcrum frame 168, and the base end side of the parking arm 170 is disposed on the arm support shaft 169. The boss portion 173 is pivotally supported. The parking arm 170 is formed with a plurality of locking notches 171 and a locking guide surface 172 for locking the locking projection 167 so as to be detachable.

  As shown in FIG. 14, the pressure receiving arm 174 is fixed to the boss 173 on the proximal end side of the parking arm 170. The pressure receiving arm 174 is formed with a long hole 175 that is long in the circumferential direction around the arm support shaft 169. Further, the pressure arm 176 is pivotally supported on the arm support shaft 169, the pressure pin 177 is fixed to the pressure arm 176, and the pressure pin 177 is passed through the long hole 175. A pressure spring 178 is wound around the outer periphery of the boss portion 173, one end side of the pressure spring 178 is locked to the pressure receiving arm 174, and the other end side of the pressure spring 178 is locked to the pressure pin 177. The locking protrusion 167 is elastically pressed against the locking notch 171 and the locking guide surface 172 by the urging force of the pressure spring 178.

  On the other hand, the parking brake lever 34 is disposed on the side surface of the clutch housing 10 via the lever guide frame 181 so as to be vertically movable in the standing posture. A lever shaft 184 is pivotally supported on the step frame 13 via a support shaft body 183. The first arm 186 of the lever shaft 184 is connected to the lower end side of the parking brake lever 34 via the pin 185. One end side of the parking link 189 is connected to the second arm 187 of the lever shaft 184 via a pin 188.

  On the other hand, the pressure arm 176 described above is connected to the other end of the parking link 189 via a pin 190. The pin 190 and the other end side of the fulcrum crossing arm 191 whose one end side is fixed to the fulcrum frame 168 are connected by a fulcrum crossing spring 192. That is, the parking brake lever 34 is maintained by the fulcrum spring 192 at the parking brake applied position on the rising side or the parking brake cut position on the descending side.

  With reference to FIG. 14, a parking brake operation for maintaining the brake pedal 33 in the depressed position by operating the parking brake lever 34 will be described. 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 151 (the arrow in FIG. 17, clockwise rotation) and engage with the locking notch 171. The locking projection 167 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 position (parking brake on). In this case, the pressure arm 176 is rotated against the fulcrum spring 191, and the parking brake lever 34 is held in the raised position by the fulcrum spring 191. The pressure pin 177 rotates about the arm spindle 169 by the rotation of the pressure arm 176, and the pressure receiving arm 174 and the parking arm 170 rotate in conjunction with each other via the pressure pin 177, and the locking projection 167. The locking guide surface 172 comes into contact with. Therefore, when the operator releases the right foot from the brake pedal 33, the locking projection 167 is engaged with the locking notch 171 by the guide of the locking guide surface 172, 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 191. Thus, the pressure arm 176 is rotated and the parking brake lever 34 is held in the lowered position by the fulcrum spring 191. The pressure pin 177 is rotated around the arm spindle 169 by the rotation of the pressure arm 176, and the pressure receiving arm 174 and the parking arm 170 are interlocked via the pressure pin 177 by the urging force of the pressure spring 178. The locking notch 171 is separated from the locking projection 167, and the brake pedal 33 is returned from the depressed position to the initial position by the urging force of the brake release spring 165. 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, with reference to FIGS. 11, 12, and 14, 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 described. . As shown in FIGS. 12 and 14, the above-described fulcrum frame 168 is passed through one end side of a round bar-shaped release arm 193 as a braking system release means. One end side of the release arm 193 penetrating the fulcrum frame 168 is disposed substantially parallel to the brake pedal shaft 151 extending in the left-right direction of the traveling machine body 2. The protruding end side of the release arm 193 protruding to the right side of the fulcrum frame 168 and the lock arm 166 are connected via a release link mechanism 194. The release arm 413 is rotatably assembled via the release link mechanism 194 by swinging the lock arm 166. In conjunction with the operation of the brake pedal 33 that rotates about the brake pedal shaft 151, the release arm 193 rotates about the axis line via the lock arm 166 and the release link mechanism 194.

  On the other hand, as shown in FIG. 11, the other end side of the release arm 193 protrudes to the right side of the fulcrum frame 168, and the other end side of the release arm 193 is bent into a substantially L shape so that the release operation portion 193a is integrated. To form. In addition, a round bar-shaped release protrusion 195 is fixed to the above-described locking link 144, and the release operation portion 193a and the release protrusion 195 are arranged on a straight line extending in the aircraft 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. 11, the cruise lever 38 is pulled up from the phantom line position to the solid line position by the operator, and the locking link 144 is operated from the imaginary line position to the solid line position. When the locking body 143 is engaged with the locking claw 142 and the vehicle speed maintaining mechanism 141 is maintained in the auto-cruise (vehicle speed maintaining) state, the release arm is depressed by depressing the brake pedal 33. When 193 rotates around the axis line, the release operation portion 193a comes into contact with the release protrusion 195 to forcibly move the locking link 144 at the solid line position in the direction of the virtual line position.

  Therefore, the locking body 143 is forcibly released from the locking claw 142, the vehicle speed maintenance mechanism 141 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. 11, 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 143. Is held at a non-engagement position separated from the locking claw 142. As described above, when the vehicle speed maintaining mechanism 141 is held in the released state, the release protrusion 195 is positioned outside the rotational trajectory range of the release operation portion 193a. Even if it rotates around, the release operation part 193a does not contact the release protrusion 195. Therefore, the brake pedal 33 can be operated in a state where the cruise lever 38 is securely held at the off position.

  As shown in FIGS. 13 and 15, the switch operating piece 196 is fixed to the parking brake lever 34 described above, and the parking switch 197 is fixed to the right side surface of the clutch case 10. By moving the parking brake lever 34 from the parking brake cut position to the entering position, holding the brake pedal 33 in the stepped position, and maintaining the brake mechanism 32 for braking the rear wheel in the braking state, the parking switch 197 is turned on. The parking brake applied operating state is detected, the parking brake lamp (not shown) of the meter panel 62 is turned on, and the parking brake applied operating state is displayed.

  Next, with reference to FIG. 16 thru | or FIG. 19, transmission structures, such as a clutch and a brake of the mid PTO shaft 28 of this embodiment, are demonstrated. The PTO output case 231 is detachably fastened to the rear part of the bottom surface of the mission case 11 described above (see FIGS. 16 and 19). A mid PTO shaft 28 is rotatably mounted on the PTO output case 231. A mid PTO clutch 232 and a mid PTO brake 233 are disposed on the mid PTO shaft 28 in the PTO output case 231 (see FIG. 17). The rotation from the engine 5 is transmitted to the mid PTO clutch 232 via the mid PTO input gear 234, and the mid PTO shaft 28 is driven. On the other hand, the mid PTO brake 233 brakes the mid PTO shaft 28.

  Further, a mid PTO clutch shaft 235 for turning on and off the mid PTO clutch 232 and a mid PTO brake shaft 236 for operating the mid PTO brake 233 are disposed in the PTO output case 231. One end side of each of the mid PTO clutch shaft 235 and the mid PTO brake shaft 236 protrudes to the left side of the mission case 11 in the forward direction. A clutch link 237 is disposed on one end side of the mid PTO clutch shaft 235. A brake link 238 is disposed on one end side of the mid PTO brake shaft 236.

  Next, the operation structure of the mid PTO clutch 232 will be described with reference to FIGS. The mid PTO clutch operation shaft 240 is rotatably fitted to the rear PTO clutch operation shaft 239 protruding to the left side of the mission case 11 in the forward direction (see FIG. 17). One end side of the lever substrate 241 is connected to the mid PTO clutch operating shaft 240. The above-described mid PTO clutch lever 44 is connected to the other end side of the lever substrate 241 via a leaf spring body 242 that can be bent in the lateral direction.

  The lever base plate 241 is connected to a clutch operating rod 243 and a fulcrum overspring 244. A clutch link 237 is connected to the lever base plate 241 via a clutch operation rod 243. By rotating the mid PTO clutch lever 44 around the rear PTO clutch operation shaft 239, the mid PTO clutch 232 is engaged or disengaged via the clutch operation rod 243 and the clutch link 237. The mid PTO clutch lever 44 is maintained at the disengagement position of the mid PTO clutch 232 by the position holding action of the spring 244. Note that the mid PTO clutch lever 44 is maintained at the entering position by a detent mechanism (not shown) of the mid PTO clutch 232. Further, the spring 244 acts on the mid PTO clutch lever 44 so as to assist the operation of the mid PTO clutch lever 44 (operation by the operator), thereby reducing the operation force of the mid PTO clutch lever 44.

  Next, the operation structure of the mid PTO brake 233 will be described with reference to FIGS. Similarly to the mid PTO clutch operation shaft 240, the mid PTO brake operation shaft 245 is rotatably fitted on the rear PTO clutch operation shaft 239 protruding to the left side of the mission case 11 in the forward direction. The rear arm 245a of the mid PTO brake operation shaft 245 is connected to the brake link 238 via the brake operation rod 246.

  Note that a clutch operation rod 243 and a brake operation rod 246 extend in the vertical direction behind the rear axle case 11a. In other words, the PTO output case 231 below the rear axle case 11a on the rear end side of the mission case 11, and the mid PTO clutch operating shaft 240 and the mid PTO brake operation above the rear axle case 11a on the rear end side of the mission case 11. A clutch operating rod 243 and a brake operating rod 246 are disposed between the shaft 245 and the shaft 245. The clutch operation rod 243 and the brake operation rod 246 are extended in the vertical direction along the left side surface of the transmission case 11 behind the rear axle case 11a.

  Further, the base plate 248 of the brake operation intermediate shaft 247 is fastened to the left side surface (left side in the forward direction) of the transmission case 11 in front of the rear axle case 11a, and intermediate between the vertical widths of the left side surface of the transmission case 11 The bearing body 247 is disposed, and the intermediate bearing body 247 projects substantially horizontally from the left side surface of the mission case 11 toward the outside. A brake operation intermediate shaft 251 in which a short arm 249 and a long arm 250 are provided in a bell crank shape is rotatably fitted to the intermediate bearing body 247. The short arm 249 is connected with the upward arm 245b of the mid PTO brake operation shaft 245 via a stroke absorbing spring body 252 that extends with a substantially constant tensile force (operation force necessary for braking the mid PTO brake 233) or more.

  The clutch pedal 31 described above is coupled to the long arm 250 via a pedal coupling mechanism 253. The pedal coupling mechanism 253 includes a link boss body 254 that is rotatably fitted to the above-described four-wheel drive switching operation shaft 78, and an upper link 255 and a lower link 256 that protrude from the link boss body 254 in a bell crank shape in the vertical direction. The lower link 256 is connected to the front rod 257 for connecting the upper link 255 to the protruding piece 40d of the second clutch link 40b described above, and the lower end side of the long arm 250 extending downward from the brake operation intermediate shaft 251 described above. And a rear rod 258.

  That is, the lower end side of the long arm 250 is connected to the clutch pedal 31 via the protruding piece 40d of the second clutch link 40b, the front rod 257, the upper arm body 255 and the lower arm body 256, and the rear rod 258. Are connected. The lower arm side of the long arm 250 protrudes below the bottom of the mission case 11, and the effective action length L2 of the long arm 250 is longer than the effective action length L1 of the short arm 249 by about three times or more. ing. Therefore, the long arm 250 as a brake operation link is extended downward from the brake operation intermediate shaft 251, and the clutch pedal 31 is connected to the lower end side of the long arm 250 via the pedal connection mechanism 253. The pedal coupling mechanism 253 is arranged along the lower end side on the outer side.

  Further, the clutch case 10, the transmission case 11, and the brake case shaft 30 for braking the rear wheel 4 and the four-wheel drive switching operation shaft 78 are arranged near the bottom of the clutch case 10 and the transmission front case 12, respectively. The front rod 257 and the rear rod 258 are extended in the front-rear direction on the left side of the cases 10, 11, 12 on the outer side of the four-wheel drive switching operation lever 79 along the vicinity of the bottom of the mission front case 12. That is, a four-wheel drive switching lever 79 as a shift output switching lever extending in the vertical direction on the outer side of the mission case 11 is provided, and the front rod is disposed on the outer side of the four-wheel drive switching operation lever 79 supported by the four-wheel drive switching operation shaft 78. Is arranged.

  On the other hand, an airframe cover 259 that covers the upper surface side of the clutch case 10, the mission case 11, and the mission front case 12 is provided (see FIG. 19). A lever guide hole 259 a is formed on the left side surface of the body cover 259. The 4WD switching operation lever 79 is passed through the lever guide hole 259a, and the grip 79a of the 4WD switching operation lever 79 is disposed above the left side surface of the body cover 259. That is, the grip portion 79a of the four-wheel drive switching operation lever 79 as a shift output switching lever is disposed above the step floor plate 18 as a step for getting on and off the operator seat 17 of the traveling machine body 2. A pedal coupling mechanism 253 such as a front rod 257 is disposed below.

  With the above configuration, as shown in FIG. 1, the mower working machine 29 is mounted below the traveling machine body 2 between the front wheel 3 and the rear wheel 4, and the transmission shaft 29 a is attached to the above-described mid PTO shaft 28. The input unit of the mower working machine 29 is connected through the via. Then, the mid PTO clutch lever 44 is operated to activate the mid PTO clutch 232, rotate the mowing blade of the mower working machine 29 via the mid PTO shaft 28, and perform mowing work such as turf grass. When the operator sitting on the control seat 17 depresses the clutch pedal 31 during the mowing, the main clutch 9 is disengaged and the transmission of the rotational force from the engine 5 to the transmission case 11 and the mid PTO shaft 28 is interrupted. Is done. At substantially the same time, when the clutch pedal 31 is stepped on, the front rod 257 is pulled, the rear rod 258 is pushed, and the mid PTO brake 233 is actuated via the stroke absorbing spring body 252. The shaft 28 is braked. Therefore, the stepping operation of the clutch pedal 31 can forcibly stop the mowing blade or the like of the mower working machine 29 urgently and can prevent the mowing blade or the like of the mower working machine 29 from rotating due to inertia.

  As is clear from the above description and FIGS. 1, 16 to 19, the engine 5 mounted on the traveling machine body 2, the transmission case 11 that transmits the power from the engine 5 via the main clutch 9 as a clutch mechanism, A transmission case 11 includes a mid PTO shaft 28 that transmits power from the engine 5 to a mid-mount work machine such as a mower work machine 29 connected to the traveling machine body 2, and a mid PTO brake 233 that brakes the mid PTO shaft 28. The brake operation intermediate shaft 251 is disposed on the side surface of the motor, the mid PTO brake 233 is connected to the brake operation intermediate shaft 251, and the mid PTO brake 233 is braked by the turning operation of the clutch pedal 31 for turning off the main clutch 9. In the work vehicle configured as described above, the brake operation intermediate shaft 251 is The long arm 250 as a brake operation link is extended toward the front side, the clutch pedal 31 is connected to the lower end side of the long arm 250 via the pedal connection mechanism 253, and the transmission case 11 is connected to the lower end side on the outer side of one side. Since the pedal connection mechanism 253 is disposed along the long arm 250, the long arm 250 can be formed to such a length that the pedal force of the clutch pedal 31 can be reduced by utilizing the lever action. It is possible to easily reduce the stepping operation force of the clutch pedal 31 to which the brake operation force for preventing the movement is added. Further, for example, the pedal coupling mechanism 253 can be easily assembled to the lower end of the transmission case 11 on one side and outside with almost no restriction by the four-wheel drive switching operation lever 79 as a shift output switching lever. Workability such as attachment / detachment and maintenance of the pedal coupling mechanism 253 can be improved.

  As is clear from the above description and FIGS. 16 to 19, the pedal coupling mechanism 253 has a front rod 257 coupled to the clutch pedal 31 and a rear rod 258 coupled to the lower end side of the long arm 250. The upper arm body 255 and the lower arm body 256 for connecting the front rod 257 and the rear rod 258 to the four-wheel drive switching operation shaft 78 as a shift output switching shaft protruding from the side surface of the transmission case 11 can be rotated. For example, even if the brake operation intermediate shaft 251 and the clutch pedal 31 are separated from each other, the pedal connection mechanism 253 is attached to a plurality of parts with the four-wheel drive operation shaft 78 interposed therebetween. It can be formed by dividing, and the connection rigidity of the pedal connection mechanism 253 can be easily secured. Further, since it is not necessary to specially install a support shaft and a bearing for incorporating the pedal coupling mechanism 253, the traveling machine body 2 such as the transmission case 11 for arranging the pedal coupling mechanism 253 can be easily formed.

  As is apparent from the above description and FIGS. 16 to 19, the four-wheel drive switching operation lever 79 is provided as a shift output switching lever that extends in the vertical direction outside the mission case 11, and is supported on the four-wheel drive switching operation shaft 78. Since the front rod 257 is disposed on the outer side of the four-wheel drive switching lever 79, a shift output switching lever can be formed without being restricted by the pedal coupling mechanism 253 such as the front rod 257 and the like on the side of the transmission case. Along with this, the four-wheel drive switching operation lever 79 can be assembled compactly. Further, the pedal connection mechanism 253 such as the front rod 257 can be easily assembled by changing the length of the four-wheel drive switching operation shaft 78 in the axial direction without changing the support structure of the four-wheel drive switching operation lever 79. Can be attached.

  As apparent from the above description and FIGS. 16 to 19, the grip portion 79 a of the four-wheel drive switching operation lever 79 is provided above the step floor plate 18 as a step of getting on and off the operator on the control seat 17 of the traveling body 2. Since the pedal connection mechanism 253 such as the front rod 257 is arranged below the step floor plate 18, the assembly of the four-wheel drive switching operation lever 79 and the assembly of the pedal connection mechanism 253 are mutually restricted. As a result, the assembly workability of the 4WD switching operation lever 79 and the pedal coupling mechanism 253 can be improved. For example, the grip portion 79a of the four-wheel drive switching operation lever 79 hardly protrudes into the operator's boarding / alighting space on the upper surface side of the step floor plate 18, and the grip portion of the four-wheel drive switching operation lever 79 is located at a position that does not obstruct the operator's getting on / off. 79a can be arranged compactly.

It is a right view of the whole tractor. It is a top view of the whole tractor. It is a perspective view of the traveling machine body. It is a top view of the pedal etc. which an operator operates. It is a perspective view of the pedal etc. which an operator operates. It is a side view of the front part of the traveling machine body. It is a perspective view of the front part of the traveling machine body. It is side views, such as a forward pedal, a reverse pedal, and a speed change link mechanism. FIG. 9 is an enlarged side view of the forward pedal and the reverse pedal of FIG. 8. It is plane explanatory drawings, such as a forward pedal and a reverse pedal. It is a side view explaining operation of a cruise lever or the like. It is a perspective view, such as a brake pedal. It is side surface explanatory drawing, such as a brake pedal. FIG. 14 is an enlarged side view of FIG. 13. FIG. 14 is an enlarged perspective view of FIG. 13. It is a side view of the operation mechanism of a mid PTO brake. It is a top view of the operation mechanism of a mid PTO brake. It is a rear view perspective view of the operation mechanism of a mid PTO brake. FIG. 17 is an enlarged side view of FIG. 16.

2 traveling machine body 5 engine 9 main clutch (clutch mechanism)
11 Mission Case 17 Control Seat 18 Step Floor Board (Boarding Step)
28 Mid PTO shaft 29 More work machine 31 Clutch pedal 78 4WD switching operation shaft (shift output switching shaft)
79 4WD switching operation lever (shift output switching lever)
79a Grip part of 4WD switching operation lever 233 Mid PTO brake 250 Long arm (brake operation link)
251 Brake operation intermediate shaft 253 Pedal coupling mechanism 255 Upper arm body 256 Lower arm body 257 Front rod 258 Rear rod

Claims (3)

An engine mounted on a traveling machine body, a transmission case that transmits power from the engine through a clutch mechanism, a PTO shaft that transmits power from the engine to a work machine connected to the traveling machine body, and a brake for the PTO shaft And a PTO brake for disposing a brake operation intermediate shaft on a side surface of the transmission case, connecting the PTO brake to the brake operation intermediate shaft, and disengaging the clutch mechanism to disengage the clutch mechanism. In a work vehicle configured to brake a PTO brake,
A brake operation link is extended downward from the brake operation intermediate shaft, the clutch pedal is connected to the lower end side of the brake operation link via a pedal connection mechanism, and the transmission case is connected to the lower end side on the outer side of the transmission case. Along the way, arrange the pedal coupling mechanism ,
The pedal coupling mechanism includes a front rod coupled to the clutch pedal and a rear rod coupled to the lower end side of the brake operation link, and the shift output switching shaft protruding from the side surface of the transmission case has the front side A work vehicle characterized in that an arm body for connecting a rod and a rear rod is rotatably fitted . 2. A shift output switching lever extending in an up-down direction on the outer side of the transmission case, and the front rod is disposed on the outer side of the shift output switching lever supported by the shift output switching shaft. The work vehicle as described in. A grip output portion of the shift output switching lever is disposed above the getting-on / off step for an operator to get on and off the control seat of the traveling machine body, and the pedal coupling mechanism such as the front rod is arranged below the getting-on / off step. The work vehicle according to claim 2, wherein

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