JP5971848B2 - Agricultural tractor - Google Patents

Description

  The present invention relates to an agricultural tractor in which a ground work machine is mounted behind a traveling machine body so as to be lifted and lowered by a lift arm.

  Conventionally, agricultural tractors include a traveling machine body on which an engine and a mission case are mounted, a lift arm provided on the rear upper surface side of the transmission case so as to be able to swing up and down, and a lifting hydraulic cylinder that swings the lift arm up and down. And an elevating hydraulic cylinder is externally mounted behind the mission case (see, for example, Patent Document 1).

Japanese Patent No. 3526988

  By the way, if the piping connecting the raising / lowering hydraulic switching valve and the raising / lowering hydraulic cylinder is long, there is a disadvantage that the temperature of the hydraulic oil tends to increase due to, for example, the pipe resistance of the piping. In this regard, in the agricultural tractor disclosed in Patent Document 1, the raising / lowering hydraulic switching valve for the raising / lowering hydraulic cylinder is disposed at the corner portion on the rear upper side inside the transmission case so as to enter below the pivot fulcrum portion of the lift arm. The piping connecting the lifting hydraulic switching valve and the lifting hydraulic cylinder is shortened.

  However, in the configuration of Patent Document 1, since the lifting hydraulic switching valve is inside the mission case and enters below the pivot fulcrum of the lift arm, the lifting hydraulic switching valve itself and the maintenance work around it are not performed. There was a problem that it could not be done easily.

  This invention makes it a technical subject to provide the agricultural tractor which examined and improved the above present condition.

The invention of the present application comprises a traveling machine body on which an engine and a transmission case are mounted, a lift arm provided on the rear side of the upper surface of the transmission case so as to be able to swing up and down, and a lifting hydraulic cylinder that swings the lift arm up and down, An agricultural tractor externally provided with the elevating hydraulic cylinder on the rear side of the mission case, the hydraulic case accommodating the elevating hydraulic switching valve for the elevating hydraulic cylinder is provided on the upper surface of the mission case, and the lift A variable throttle valve / stop valve for adjusting the lowering speed of the arm and a relief valve located between the lift hydraulic cylinder and the variable throttle valve / stop valve are provided on the upper surface side of the hydraulic case, and the lift Via a feedback link to the pivot shaft of the operating member for manually switching the hydraulic switching valve for operation and the lift arm A feedback operation shaft connected to the hydraulic case, the hydraulic operation case is pivotally supported, and the operation member and the feedback link are arranged together on one side of the hydraulic case. A hydraulic pump that supplies hydraulic oil to the elevating hydraulic cylinder is disposed on the opposite side of the operation member and the feedback link across the hydraulic case on the upper surface of the case .

  According to the invention of the present application, the vehicle includes a traveling machine body on which an engine and a transmission case are mounted, a lift arm that can swing up and down on the upper rear side of the transmission case, and a lift hydraulic cylinder that swings the lift arm up and down. An agricultural tractor externally provided with the elevating hydraulic cylinder on the rear side of the mission case, wherein a hydraulic case for accommodating an elevating hydraulic switching valve for the elevating hydraulic cylinder is provided on the upper surface of the mission case, Since the variable throttle valve / stop valve for adjusting the descending speed of the lift arm and the relief valve located between the elevating hydraulic cylinder and the variable throttle valve / stop valve are provided on the upper surface side of the hydraulic case, The piping extending from the lifting hydraulic switching valve to the lifting hydraulic cylinder through the variable throttle valve and stop valve can be shortened. While seeking the can improve maintenance workability as compared with the structure of providing the variable throttle valve and check valve and the relief valve in the transmission case, the help of the maintenance cost containment.

According to the present invention, the rotary support shaft of the operation member for manually switching the lifting hydraulic switching valve and the feedback operation shaft connected to the lift arm via a feedback link have a double shaft structure. And configured to pivotally support the hydraulic case, the operation member and the feedback link are collectively arranged on one side of the hydraulic case, and the operation member is sandwiched between the hydraulic case on the upper surface of the transmission case. And a hydraulic pump for supplying hydraulic oil to the elevating hydraulic cylinder on the opposite side of the feedback link, the hydraulic case, the feedback link, and the operation are effectively utilized in the space on the transmission case. The member and the hydraulic pump can be arranged compactly.

It is a side view of an agricultural tractor. It is a top view of the agricultural tractor. It is the perspective view which looked at the mission case from the left rear. It is the perspective view which looked at the mission case from the right rear. It is plane sectional drawing of a mission case rear part. It is a hydraulic circuit diagram of an agricultural tractor. It is a top view of a mission case and a hydraulic case. It is a side view of a hydraulic case. It is a back perspective view of a hydraulic case. It is side surface sectional drawing of a hydraulic case. It is a partially cutaway rear view of a hydraulic case.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments embodying the present invention will be described with reference to the drawings (FIGS. 1 to 5). As shown in FIGS. 1 and 2, an agricultural tractor 1 (hereinafter simply referred to as a tractor 1) supports a traveling machine body 2 by a pair of left and right front wheels 3 and a pair of left and right rear wheels 4. In the following description, the left side in the forward direction of the traveling machine body 2 is simply referred to as the left side, and the right side in the forward direction is also simply referred to as the right side. The tractor 1 is configured to travel forward and backward by driving the rear wheels 4 and the front wheels 3 with an engine 5 mounted on the front portion of the traveling machine body 2. The engine 5 is covered with a bonnet 6. A fuel tank 13 is disposed behind the engine 5. The fuel tank 13 is also covered with the bonnet 6.

  A handle column 7 is disposed at the rear of the bonnet 6. The handle column 7 is provided with a steering handle 9 for steering the left and right front wheels 3 to the left and right. A control seat 8 is disposed behind the control handle 9 on the upper surface of the traveling machine body 2. On the right side of the control seat 8, a work implement lifting lever 14 for manually changing and adjusting the height position of a rotary tiller 24 described later is disposed. The work implement elevating lever 14 is configured to lower the rotary tiller 24 by a forward tilting operation and to raise the rotary tiller 24 by a backward tilting operation.

  A step 10 in which an operator gets on the lower part of the handle column 7 is provided. A clutch pedal 11 is provided on the left side of the handle column 7 on the upper surface of the step 10, and a brake pedal 12 is provided on the right side of the handle column 7. The operator who sits on the control seat 8 holds the control handle 9 and steps on the clutch pedal 11 and the brake pedal 12.

  On the other hand, a mission case 17 for shifting the rotation of the engine 5 and transmitting it to the left and right rear wheels 4 and the front wheels 3 is disposed at the rear of the traveling machine body 2. Left and right rear axle cases 18 are mounted so as to protrude outward from the left and right outer surfaces of the mission case 17. Left and right rear axle cases 19 are inserted into the left and right rear axle cases 18. The rear wheel 4 is attached to the mission case 17 via the rear axle 19.

  Further, a rear PTO shaft 23 is provided on the rear side surface of the transmission case 17 so as to protrude rearward for transmitting the PTO driving force rearward. The tractor 1 of the embodiment includes a rotary cultivator 24 as a ground working machine and a three-point link mechanism 20 connected to the rear part of the traveling machine body 2. The three-point link mechanism 20 includes a pair of left and right lower links 21 and a top link 22. The rotary cultivator 24 is connected to the rear portion of the mission case 17 via a three-point link mechanism 20.

  As shown in FIGS. 3 and 4, the front end side (base end side) of the left and right lower link 21 rotates to the hitch portion 18 a of the rear end portion of the rear axle case 18 via a horizontally long lower link pin shaft 25. Connected as possible. A front end side of the top link 22 is connected to a link hitch 26 on the rear side of the mission case 17 via a top link pin 27. The front end side (base end side) of the sway chain 33 that restricts the swinging of the lower link 21 in the left-right direction is connected to the intermediate portion of the lower link pin shaft 25 (see FIGS. 3 to 5). While pulling the rotary tiller 24 on the rear side of the tractor 1 by the three-point link mechanism 20 including a pair of left and right lower links 21 and a top link 22, the rotary tiller claw 28 of the rotary tiller 24 is moved to the rear PTO shaft 23. It is configured to perform a field work tillage by rotating with power from the power source.

  The tractor 1 according to the embodiment includes a single-acting lifting hydraulic cylinder 29 as an actuator that moves the three-point link mechanism 20 up and down. The left and right lift arms 30 are provided on the rear side of the upper surface of the mission case 17 via a lift arm shaft 34 (rotation fulcrum) so as to be swingable (rotate). The left and right lower links 21 are connected to the lift arms 30 via lift rods 31. A piston rod (upper side) of the elevating hydraulic cylinder 29 is connected to at least one of the left and right lift arms 30 (right side in the embodiment) via left and right side cylinder connecting pins 35.

  The cylinder side end portion (lower side) of the elevating hydraulic cylinder 29 is supported on the traveling machine body 2 (the rear side of the transmission case 17) via the left and right side cylinder support pins 32 (the pivot pin shaft). In this case, a cylinder support pin 32 as a pivot pin shaft is provided on a bracket portion 17a integrally formed on the rear surface side of the transmission case 17 and a hitch portion 18a integrally formed on the rear end portions of the left and right rear axle cases 18. The lifting hydraulic cylinder 29 is supported via (See FIGS. 3 to 5).

  That is, a hitch portion 18a integrally formed so as to project rearward at least on the left and right rear axle case 18 (right side in the embodiment) and a bracket portion integrally formed so as to protrude rearward on the rear surface of the transmission case 17. A lower side of the elevating hydraulic cylinder 29 is disposed between the lower side 17a and the lower side 17a. The cylinder support pin 32 is passed through the hitch portion 18a, the lower side of the elevating hydraulic cylinder 29, and the bracket portion 17a, and the cylinder support pin 32 is supported by the hitch portion 18a and the bracket portion 17a in a doubly supported beam shape. A fixing plate 36 is provided at the protruding end of the cylinder support pin 32 that protrudes to the left and right outside of the hitch portion 18a. By fastening the fixing plate 36 to the outer surface of the hitch portion 18a, the cylinder support pin 32 is held so as not to come off.

  The bracket portion 17 a of the embodiment protrudes rearwardly between the rear PTO shaft 23 on the rear surface of the transmission case 17 and the hitch portion 18 a of the rear axle case 18. For this reason, the elevating hydraulic cylinder 29 is disposed offset to the left or right (the side where the bracket portion 17a is located) from the left and right center of the traveling machine body 2 where the rear PTO shaft 23 is located.

  Thus, if the cylinder support pin 32 is inserted and fixed to the hitch portion 18a of the rear axle case 18 and the lower side of the lifting hydraulic cylinder 29 and the bracket portion 17a of the transmission case 17, the lower side of the lifting hydraulic cylinder 29 can be easily fixed. It can be connected to the rear side of the mission case 17. Therefore, the number of parts constituting the shaft support structure on the lower side of the elevating hydraulic cylinder 29 can be reduced to reduce the number of assembling work, which helps to reduce manufacturing costs and maintenance costs.

  When the elevating hydraulic cylinder 29 is operated by manual operation of the work implement elevating lever 14 and its piston rod is protruded or submerged, the front end side (rear end side) of the left and right lift arms 30 swings up and down (turns). And the rear end sides of the left and right lower links 21 are rotated in the vertical direction with the lower link pin shaft 25 as a fulcrum. As a result, the rotary tiller 24 connected to the rear ends of the left and right lower links 21 moves up and down.

  As shown in FIGS. 3 to 5, the hitch portion 18 a of the embodiment is integrally formed on the left and right rear axle cases 18 so as to protrude rearward. Left and right horizontally long lower link pin shafts 25 are attached to both the left and right hitch portions 18a so as to be inserted and removed from the left and right. A front end side (base end side) of each lower link 21 is rotatably fitted on the left and right inner sides of the lower link pin shaft 25 near each hitch portion 18a. If comprised in this way, the front end side of both the left and right lower links 21 can be pivotally supported by only a single lower link pin shaft 25, and the mounting support structure of the left and right lower links 21 can be simplified. In addition, if the lower link pin shaft 25 is pulled out from the left and right hitch portions 18a, the left and right lower links 21 can be easily removed from the rear portion of the traveling machine body 2. Accordingly, it is possible to improve the attachment / detachment workability of the left and right lower links 21 and thus the rotary tiller 24 (ground work machine) attached thereto.

  A cylindrical body 37 that restricts left-right movement of the front end sides of the left and right lower links 21 is fitted in the middle part of the lower link pin shaft 25 in the longitudinal direction. A rear hitch 96 is fixed to the central portion of the cylindrical body 37. The rear hitch 96 is also fixed to the rear surface of the mission case 17 via a hitch bracket 95. Plate plates 38 that protrude rearward are attached to the left and right sides of the cylindrical body 37 with the rear hitch interposed therebetween. The front end side (base end side) of the sway chain 33 that restricts the swing of the lower link 21 in the left-right direction is connected to each plate plate 38. The rear end side (front end side) of the sway chain 33 is connected to the left and right inner surfaces near the front end of the corresponding lower link 21. If comprised in this way, each sway chain 33 will be located between the left-right both lower links 21. FIG. Therefore, there is no possibility that the sway chain 33 that restricts the swinging of each lower link 21 in the left-right direction interferes with the rear wheels 4 and the like on the left and right outer sides of the mission case 17, and the presence of the sway chain 33 does not get in the way.

  Next, the structure of the hydraulic circuit 100 of the tractor 1 will be described with reference to FIGS. The hydraulic circuit 100 of the tractor 1 includes a working hydraulic pump 101 and a charging hydraulic pump 102 that are driven by the power of the engine 5. The working hydraulic pump 101 is connected to a lifting hydraulic switching valve 103 that controls supply and discharge of hydraulic oil to and from the lifting hydraulic cylinder 29. The lifting hydraulic switching valve 103 is housed in a hydraulic case 110 that is detachably provided on the upper surface of the mission case 17 (see FIGS. 9 to 11). When the work implement elevating lever 14 is manually operated, the elevating hydraulic pressure switching valve 103 is switched and the elevating hydraulic cylinder 29 is expanded and contracted. As a result, the lift arm 30 rotates up and down, and the rotary tiller 24 moves up and down via the three-point link mechanism 20. As shown in FIG. 7, the working hydraulic pump 101 is located on the left side of the hydraulic case on the upper surface of the mission case 17. That is, the working hydraulic pump 101 is provided on the upper side of the transmission case 17 on the opposite side of the working machine lifting lever 14 and the feedback link 123 (details will be described later) across the hydraulic case 110.

  A variable throttle valve / stop valve 104 for adjusting the shortening speed of the lifting hydraulic cylinder 29 (which can also be said to be the lowering speed of the lift arm 30) is provided in the hydraulic fluid passage 106 connecting the lifting hydraulic switching valve 103 and the lifting hydraulic cylinder 29. Provided. As shown in FIG. 9, the hydraulic oil passage 106 is formed on the upper surface side of the hydraulic case 110. The variable throttle valve / stop valve 104 is detachably mounted on the upper front side of the hydraulic case 110. The operation rod 104 a of the variable throttle valve / stop valve 104 protrudes forward from the front side of the hydraulic case 110. The adjustment knob 104b attached to the distal end side of the operation rod 104a is located at the lower front portion of the control seat 8. The variable throttle valve / stop valve 104 is adjusted through the operation rod 104a by rotating the adjusting knob 104b.

  A branch oil passage 107 is connected between the variable throttle valve / stop valve 104 and the elevating hydraulic cylinder 29 in the hydraulic oil passage 106. In the branch oil passage 107, a damage prevention relief valve 105 for releasing the pressure between the variable throttle valve / stop valve 104 and the elevating hydraulic cylinder 29 in the hydraulic oil passage 106 is provided. For example, if the load applied to the rotary tiller 24 increases and the link arm 30 and thus the lifting hydraulic cylinder 29 are overloaded more than expected, the hydraulic oil pressure in the hydraulic oil passage 106 becomes too high, and the lifting hydraulic cylinder 29, there is a risk of failure of the lifting hydraulic switching valve 103, the variable throttle valve / stop valve 104, and the like. In such a case, the damage prevention relief valve 105 is configured to allow hydraulic oil in the elevating hydraulic cylinder 29 to escape to the transmission case 17 side. The operation of the damage prevention relief valve 105 prevents the hydraulic oil passage 106 from being overloaded. The damage prevention relief valve 105 is detachably mounted on the upper rear side of the hydraulic case 110.

  Although not shown, the charging hydraulic pump 102 is configured to supply hydraulic oil to a hydraulic continuously variable transmission provided in the mission case 17, a steering hydraulic cylinder for power steering, or the like. The hydraulic circuit 100 also includes a relief valve and an oil filter.

  Next, the lifting mechanism 111 provided in the hydraulic case 110 and its peripheral structure will be described with reference to FIGS. The hydraulic case 110 is provided with an elevating mechanism 111 that controls driving of the elevating hydraulic cylinder 29. The lifting mechanism 111 mechanically switches the lifting hydraulic switching valve 103 during manual operation of the work implement lifting lever 14 as an operation member. In this case, the lifting / lowering hydraulic cylinder 29 is expanded / contracted via the lifting / lowering hydraulic switching valve 103 and the variable throttle valve / stop valve 104 by manual operation of the work implement lifting / lowering lever 14. By the operation of 123, the lifting hydraulic switching valve 103 is returned to the neutral position. As a result, the rotary tiller 24 is held at an arbitrary tillage height position according to the amount of manual operation of the work implement lifting lever 14.

  As shown in FIG. 7 to FIG. 9 and FIG. 11, a work implement elevating lever 14 is provided on one of the left and right sides of the hydraulic case 110 (right side in the embodiment) so as to be able to tilt (turn). In this case, the cylindrical rotation support shaft 112 is fitted on the left and right horizontally long feedback operation shaft 122 so as to be relatively rotatable, and the rotation support shaft 112 and the feedback operation shaft 122 can be rotated on the right side surface of the hydraulic case 110. It penetrates. The rotation support shaft 112 and the feedback operation shaft 122 have a concentric double shaft structure. The base end side of the work implement lifting lever 14 is fixed by welding to a portion of the rotating support shaft 112 exposed to the right outside from the hydraulic case 110. The work implement elevating lever 14 rotates back and forth around the rotation support shaft 112.

  An outward projecting portion of the feedback operation shaft 122 from the rotation support shaft 112 is connected to the proximal end side of the right lift arm 30 via a feedback link 123. When the left and right lift arms 30 are turned up and down by manual operation of the work implement lifting lever 14, the displacement (phase) of the left and right lift arms 30 is fed back to the feedback operation shaft 122 via the feedback link 123. That is, the left and right lift arms 30 are rotated up and down by following the operation amount and the operation direction of the work machine elevating lever 14, and the rotary tiller 24 is moved up and down. As is clear from the structure of the rotation support shaft 112 and the feedback operation shaft 122, the work implement lifting lever 14 and the feedback link 123 are collectively arranged on the left and right sides (right side in the embodiment) of the hydraulic case 110. Has been. The lift arm shaft 34 that is a pivotal fulcrum portion of the lift arm 30 and the double shaft structures 112 and 122 that are pivotally supported by the hydraulic case 110 are in a positional relationship close to each other.

  A portion of the rotation support shaft 112 in the hydraulic case 110 is connected to the lower end side of the seesaw link 130 via the lower interlocking arm 114. On the other hand, a portion of the feedback operation shaft that protrudes inward from the rotation support shaft 112 in the hydraulic case 110 is connected to the upper end side of the seesaw link 130 via the upper interlocking arm 124. The middle part of the seesaw link 130 is configured to be able to contact the spool of the lifting hydraulic switching valve 103. By appropriately converting the operating force from the work implement lifting lever 14 and the feedback acting force from the lift arm 30 and transmitting them to the seesaw link 130, the lifting hydraulic switching valve 103 is switched. As a result, the lifting hydraulic cylinder 29 is held in an arbitrary expansion / contraction state according to the manual operation amount of the work implement lifting lever 14.

  As shown in FIGS. 7 to 9 and 11, a lever support plate 131 is bolted to the right side surface of the hydraulic case 110. On the upper side of the lever support plate 131, an arc-shaped guide slot 132 centering on the rotation support shaft 112 is formed. A shaft portion of a friction bolt 133 fixed to the work implement lifting lever 14 is slidably inserted into the guide groove hole 132 of the lever support plate 131. A spacer 134 is disposed between the lever support plate 131 and the work implement lifting lever 14, and a friction plate 135 is disposed on the left side of the lever support plate 131. The shaft portion of the friction bolt 133 is passed through the spacer 134 and the friction plate 135. A pair of washers 136 are fitted on the shaft portion of the friction bolt 133, and two sets of four disc springs 137 are fitted between the washers 136. Further, a double nut 138 is screwed and fitted on the tip end side of the shaft portion.

  By tightening the double nut 138, the friction plate 135 is pressure-bonded to the lever support plate 131 using the elastic restoring force of the disc spring 137, and the lever support plate 131 and the work of the friction plate 135 and the head of the friction bolt 133 are operated. The machine lift lever 14 is clamped. By adjusting the elastic restoring force of the disc spring 137 accompanying the screwing of the double nut 138, the holding force (braking force) for holding the work implement elevating lever 14 in a predetermined operation position is adjusted.

  As is clear from the above description and FIGS. 7 to 11, the traveling machine body 2 on which the engine 5 and the transmission case 17 are mounted, the lift arm 30 provided on the rear upper surface side of the transmission case 17 so as to be vertically swingable, The agricultural tractor 1 is provided with a lifting hydraulic cylinder 29 that swings the lift arm 30 up and down, and the lifting hydraulic cylinder 29 is provided externally on the rear side of the transmission case 17. A hydraulic case 110 for accommodating a hydraulic switch valve 103 for raising and lowering is provided on the upper surface of the transmission case 17, and a variable throttle valve / stop valve 104 for adjusting the lowering speed of the lift arm 30, the hydraulic cylinder 29 and the variable A relief valve 105 located between the throttle valve and stop valve 104 is provided on the upper surface side of the hydraulic case 110. Therefore, the pipe 106 extending from the lift hydraulic switching valve 103 to the lift hydraulic cylinder 29 via the variable throttle valve / stop valve 104 can be shortened, while the variable throttle valve is installed in the transmission case 17. Maintenance workability can be improved as compared with the structure in which the double stop valve 104 and the relief valve 105 are provided, which helps to reduce maintenance costs.

  As is apparent from the above description and FIGS. 7 to 11, the rotation support shaft 112 of the operation member 14 for manually switching the lifting hydraulic switching valve 103 and the feedback link 123 to the lift arm 30. The feedback operation shaft 122 connected via the shaft is configured in a double shaft structure, and is pivotally supported by the hydraulic case 110, and the operation member 14 and the feedback link 123 are arranged on one side of the hydraulic case 110. A hydraulic pump 101 that supplies hydraulic oil to the elevating hydraulic cylinder 29 is arranged on the opposite side of the operation member 14 and the feedback link 123 across the hydraulic case 110 on the upper surface of the mission case 17. Therefore, the space on the mission case 17 is effectively used, so that the hydraulic case 110, the Over-back link 123, the operating member 14 and the hydraulic pump 101 can be arranged compactly.

  As apparent from the above description and FIGS. 7 to 11, the rotation fulcrum 34 of the lift arm 30 and the double shaft structures 112 and 122 of the hydraulic case 110 are brought close to each other. The length can be shortened and the cost of parts can be reduced.

  The present invention is not limited to the above-described embodiment, and can be embodied in various forms. The configuration of each part is not limited to the illustrated embodiment, and various modifications can be made without departing from the spirit of the present invention.

2 traveling machine body 5 engine 14 work machine elevating lever 17 mission case 29 elevating hydraulic cylinder 30 lift arm 34 lift arm shaft (rotating fulcrum)
DESCRIPTION OF SYMBOLS 100 Hydraulic circuit 101 Hydraulic pump 103 for work machines Lifting hydraulic switching valve 104 Variable throttle valve stop valve 105 Damage prevention relief valve 106 Hydraulic oil path 107 Branching oil path 110 Hydraulic case 111 Elevating mechanism 112 Rotating support shaft 122 Feedback operation axis 123 Feedback link 130 Seesaw link

Claims (1)

A traveling body equipped with an engine and a transmission case, a lift arm provided on the upper rear side of the transmission case so as to be swingable up and down, and a lifting hydraulic cylinder for swinging the lift arm up and down, and a rear part of the transmission case An agricultural tractor provided with the lifting hydraulic cylinder externally on the side,
A hydraulic case that accommodates an elevation hydraulic switching valve for the elevation hydraulic cylinder is provided on the upper surface of the transmission case, and a variable throttle valve and stop valve that adjusts the lowering speed of the lift arm, the elevation hydraulic cylinder, and the variable throttle valve A relief valve located between the double stop valve and the upper side of the hydraulic case ;
A rotating shaft of an operation member for manually switching the lifting hydraulic switching valve and a feedback operation shaft connected to the lift arm via a feedback link are configured in a double shaft structure, The operation member and the feedback link are arranged together on one side of the left and right sides of the hydraulic case, and the operation member and the feedback link are sandwiched between the hydraulic case on the upper surface of the transmission case. On the opposite side, a hydraulic pump that supplies hydraulic oil to the elevating hydraulic cylinder is disposed.
Agricultural tractor.

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