JP2010280284A - Working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a working vehicle having excellent assemblability and maintainability, while switching an interlocking state of operations of pedals with engine speed. <P>SOLUTION: A hand accelerator lever 30 and the pedals 23 and 24 are arranged between an engine 5 and a driver's seat. An operation part 80 is arranged in the vicinity of the hand accelerator lever 30 and can be operated by interlocking with an operation of the hand accelerator lever 30. A pedal bracket 31 supports arms of the pedals 23 and 24. An accelerator interlocking switching mechanism 100 is supported by the pedal bracket 31. The operation part 80 and the accelerator interlocking switching mechanism 100 are connected with a first wire 66. The operation part 80 and the governor device 5a of the engine 5 are connected with a second wire 67. The accelerator interlocking switching mechanism 100 is capable of switching a state for interlocking the pedals 23 and 24 with the first wire 66 and a state for releasing the interlocking. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a work vehicle. More specifically, the present invention relates to a configuration for switching between a state in which the rotational speed of the engine is changed in accordance with the operation of the pedal and a state in which the rotational speed of the engine is substantially constant regardless of the operation of the pedal.

  2. Description of the Related Art In a work vehicle such as a farm tractor, in a farm field, it is required to perform a uniform work with a stable power and a constant work speed. For this reason, a tractor having a configuration capable of maintaining the rotational speed of the engine substantially constant has been conventionally known. In this type of tractor, the rotational speed of the engine can be adjusted by operating a hand accelerator lever or the like (with an operation position holding mechanism) disposed at the operator's hand.

  In addition, the tractor includes a hydraulic continuously variable transmission for shifting the engine output. In this configuration, even when the rotational speed of the engine is constant for work on the field, the operator can change the reduction ratio of the hydraulic continuously variable transmission by operating the pedal, for example, to increase the vehicle speed. Can be changed.

  On the other hand, when moving the vehicle body without performing work (when traveling on the road, etc.), it is not necessary to keep the engine speed constant as described above, but rather from the viewpoint of preventing noise and vibration and improving fuel efficiency. It is preferable to change the rotational speed as appropriate according to the traveling speed. Therefore, in the conventional tractor, the engine governor device is operated to the engine rotational speed increasing side in accordance with the speed increasing operation of the hydraulic continuously variable transmission by the pedal, and with the speed reducing operation of the hydraulic continuously variable transmission by the pedal. An engine governor device configured to operate on the engine speed reduction side is known. As a result, a so-called automatic vehicle-like operation can be performed.

  Therefore, the tractor as described above has a configuration capable of switching between a state in which the pedal operation and the engine rotation speed are linked and a state in which the engine rotation speed is kept substantially constant regardless of the pedal operation. Necessary.

  For example, Patent Document 1 discloses a technique for switching whether or not to change the rotational speed of the engine in conjunction with the operation of the pedal. In Patent Document 1, when the sub-shift lever is operated to the high speed shift position (when traveling on the road), the speed change arm of the hydraulic continuously variable transmission and the speed adjustment of the engine which are operated in conjunction with each other via a rod by a foot pedal. When the release wire that interlocks with the lever reveals the cooperative state where the inner wire is stretched, and when the sub-shift lever is operated to the neutral shift position and the low speed shift position (when working in the field), the release wire is The outer wire end portion of the release wire is attached to the auxiliary transmission lever so that a non-cooperating state in which the gear is loosened appears. Further, a hand accelerator lever is connected to the speed control lever via another release wire.

Japanese Patent Publication No. 6-78051

  By the way, in a farm tractor having a general configuration, the engine is disposed in the front part of the aircraft, the hydraulic continuously variable transmission and the like are disposed in the transmission case at the rear of the aircraft, and the driver's seat is disposed above the transmission case. . Moreover, a pedal, a hand accelerator lever, etc. are normally arrange | positioned in the appropriate position between an engine and a driver's seat.

  In such a tractor and the like, as in Patent Document 1, when the foot pedal, the hydraulic continuously variable transmission, and the speed control lever of the engine are interlocked and connected in this order, the foot pedal passes through the continuously variable transmission at the rear of the vehicle body. Therefore, it is necessary to provide a connection structure to the engine at the front of the vehicle body. Therefore, in the configuration of Patent Document 1, a rod that connects the foot pedal and the hydraulic continuously variable transmission, a release wire that connects the hydraulic continuously variable transmission and the engine, and the like are long, and the assembly is difficult. There was room for improvement from the viewpoint of safety and maintainability.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a work vehicle that is excellent in assemblability and maintainability while being able to switch the interlocking state between the operation of the pedal and the rotational speed of the engine. There is.

Means and effects for solving the problems

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

  According to an aspect of the present invention, there is provided a work vehicle including an engine disposed at a front portion of a vehicle body and a driver seat disposed behind the engine, and configured as follows. In other words, the work vehicle includes a hand accelerator lever, an operating unit, a pedal, a support member, and an accelerator interlocking switching mechanism. The hand accelerator lever is disposed between the engine and the driver seat in a plan view. The operating portion is disposed in the vicinity of the hand accelerator lever, and can be operated in conjunction with the operation of the hand accelerator lever. The pedal is disposed between the engine and the driver seat in plan view. The support member supports an arm portion of the pedal. The accelerator interlock switching mechanism is supported by the support member. Moreover, the said operation part and the said accelerator interlocking switching mechanism are connected by the 1st interlocking member. The operating portion and the governor device of the engine are connected by a second interlocking member. The accelerator interlocking switching mechanism can switch between a state in which the pedal and the first interlocking member are interlocked and a state in which the interlock is released.

  Thereby, by switching the presence or absence of the interlocking between the pedal and the first interlocking member by the accelerator interlocking switching mechanism, the state where the pedal and the governor device of the engine are interlocked and the state where the interlocking is released are switched. Can do. Moreover, since the operation part, the hand accelerator lever, the pedal, the accelerator interlocking switching mechanism, and the like are collectively arranged behind the engine, the first interlocking member and the second interlocking member can be shortened. Excellent maintainability.

  The work vehicle described above is preferably configured as follows. That is, this work vehicle includes a continuously variable transmission and a detection unit. The continuously variable transmission is disposed at the rear of the vehicle body and changes the output of the engine. The detection unit electrically detects an operation amount of the pedal. And based on the detection result of the said detection part, the gear ratio of the said continuously variable transmission is changed.

  As a result, the traveling speed can be steplessly changed according to the operation of the pedal. In addition, since the pedal is disposed in front of the driver's seat and the continuously variable transmission is disposed at the rear of the vehicle body, if the pedal and the continuously variable transmission are mechanically connected, The mechanical connection mechanism becomes long. In this respect, by adopting a configuration in which the pedal operation amount is electrically detected as described above, the mechanical connection mechanism between the pedal and the continuously variable transmission is omitted, and assembly and maintenance are further improved. Can be made.

  The work vehicle described above is preferably configured as follows. That is, the accelerator interlocking switching mechanism includes a first arm member, a second arm member, and a fixing member. The first arm member operates in conjunction with the pedal. The second arm member is connected to the first interlocking member and is configured to be movable relative to the first arm member. The fixing member can be switched between a state in which the first arm member and the second arm member are fixed to each other and a state in which the fixing is released.

  That is, by fixing the first arm member and the second arm member to each other by the fixing member, the pedal and the first interlocking member are interlocked. Furthermore, the first interlocking member is interlocked with the governor device of the engine via the operating part and the second interlocking member. Therefore, by fixing the first arm member and the second arm member by the fixing member, the pedal and the governor device of the engine can be interlocked. Thereby, it becomes possible to change the rotational speed of the engine by operating the pedal. On the other hand, the linkage between the pedal and the governor device is released by releasing the fixation of the first arm member and the second arm member by the fixing member. As described above, switching whether or not to change the rotation speed of the engine in conjunction with the operation of the pedal can be realized with a simple configuration.

  The work vehicle described above is preferably configured as follows. That is, the support member is attached to the step member from the lower surface side of the step member of the driver seat. The accelerator interlocking switching mechanism includes an operation tool exposed above the step member. Then, the fixing of the first arm member and the second arm member by the fixing member and the release of the fixing can be switched by the operation tool.

  Thus, the operator can operate the fixing member with the operation tool exposed above the step, so that the presence / absence of the linkage between the pedal operation and the rotation speed of the engine can be easily switched.

  The work vehicle described above is preferably configured as follows. That is, one of the first arm member and the second arm member has a fixing member support portion that rotatably supports the fixing member. The first arm member has a first insertion hole. The second arm member has a second insertion hole. The fixing member has a convex portion that can be inserted into the first insertion hole and the second insertion hole. And, by the rotation of the fixing member, at least one of the state where the convex portion is inserted into both the first insertion hole and the second insertion hole, and the first insertion hole and the second insertion hole Is configured to at least realize the state in which the convex portion is not inserted. And the said operation tool is connected with the said fixing member.

  Thereby, the said fixing member can be rotated by operating the edge part of the operation lever exposed above the step member. As described above, it is possible to realize a simple configuration in which the operator can switch from above the step whether or not to change the rotation speed of the engine in conjunction with the operation of the pedal.

  The above work vehicle can also be configured as follows. That is, the first arm member has a first insertion hole. The second arm member has a second insertion hole. The fixing member is configured as a pin-shaped member. The first arm member and the second arm member are fixed to each other by inserting the fixing member into both the first insertion hole and the second insertion hole. On the other hand, the fixing of the first arm member and the second arm member is released by removing the fixing member from at least one of the first insertion hole and the second insertion hole.

  Thereby, it is possible to switch whether or not to change the rotation speed of the engine in conjunction with the operation of the pedal with a simple configuration using insertion and removal of the pin-like member into the insertion hole.

The right view which showed the whole structure of the tractor which concerns on one Embodiment of this invention. The perspective view which shows the mode in a cabin. The skeleton figure which shows the driving force transmission mechanism of a tractor. The cross-sectional enlarged view which shows the structure of a continuously variable transmission. FIG. 3 is an external perspective view of a forward / reverse pedal unit. The right view of a forward / reverse pedal unit. The left view of a forward / reverse pedal unit. The disassembled perspective view of a forward / reverse pedal unit. The left view which shows a mode when operating a forward pedal. The left view which shows a mode when operating a reverse pedal. The right view which shows a mode when operating a forward pedal. The right view which shows a mode when operating a reverse pedal. The disassembled perspective view of an accelerator interlocking switching mechanism. The typical left view which shows a mode that the hand accelerator lever, the pedal, and the governor apparatus of the engine were connected with the wire. The right view which shows a mode when the connection with a neutral return arm and an accelerator operation arm is cancelled | released. The typical front fragmentary sectional view which shows a mode when a neutral return arm and an accelerator operation arm are connected. The typical front fragmentary sectional view which shows a mode when the connection with a neutral return arm and an accelerator operation arm is cancelled | released. The disassembled perspective view of the structure of the hand accelerator lever vicinity. The side view of the hand accelerator lever vicinity. The side view of the hand accelerator lever vicinity which shows a mode when turning a hand accelerator lever to a high-speed rotation position. The side view of the hand accelerator lever vicinity which shows a mode when a pedal is stepped on in the state which connected the neutral return arm and the accelerator operation arm. The external perspective view of the forward / reverse pedal unit according to the second embodiment. The typical front fragmentary sectional view which shows a mode when the neutral return arm and the accelerator operation arm are connected in 2nd Embodiment. The typical front fragmentary sectional view which shows a mode when the connection with a neutral return arm and an accelerator operation arm is cancelled | released in 2nd Embodiment.

  Next, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a right side view showing an overall configuration of a tractor 1 according to an embodiment of the present invention.

  A four-wheel farm work tractor 1 as a work vehicle shown in FIG. 1 supports a traveling machine body 2 with a front wheel 3 and a rear wheel 4, and a rear wheel 4 by an engine 5 disposed at a front portion of the traveling machine body 2. And by driving the front wheel 3, the traveling machine body 2 is configured to move forward or backward. The tractor 1 is configured to be able to perform various operations by attaching an unillustrated working machine such as a plow or a harrow to the rear portion as necessary.

  The traveling machine body 2 includes an engine frame 14 and a machine frame 16 fixed to a rear portion of the engine frame 14. A mission case 17 for fixing the rotation of the engine 5 to the rear wheel 4 and the front wheel 3 is appropriately fixed to the rear portion of the body frame 16.

  The engine 5 is covered with a bonnet 6. The traveling machine body 2 includes a cabin 7 disposed behind the bonnet 6. Inside the cabin 7, a driver's seat 8 for an operator to sit on and an operation unit for the operator to operate the traveling machine body 2 are arranged. The state of the operation unit inside the cabin 7 is shown in the perspective view of FIG.

  As shown in FIG. 2, a steering handle 9, a brake pedal 26, and a clutch pedal 57 are disposed inside the cabin 7. A hand accelerator lever 30 is disposed at an appropriate position near the steering handle 9.

  As shown in FIGS. 1 and 2, a horizontal step plate (step member) 12 on which an operator sitting on the driver's seat 8 places his / her foot is fixed in the cabin 7. As shown in FIG. 2, the step plate 12 is formed with a long hole, and the forward pedal arm 21 and the reverse pedal arm 22 are inserted into the cabin 7 through the long hole from below the step plate 12 (step Projecting above board 12). A forward pedal 23 is attached to the tip of the forward pedal arm 21, and a reverse pedal 24 is attached to the tip of the reverse pedal arm 22.

  The forward pedal 23 and the reverse pedal 24 are for performing a stepless speed change of the traveling speed of the traveling machine body 2 and a forward / reverse switching operation. That is, when the operator depresses the forward pedal 23, the traveling machine body 2 moves forward at a vehicle speed that is steplessly changed according to the depression amount (operation amount). On the other hand, when the reverse pedal 24 is depressed, the traveling machine body 2 is configured to move backward at a vehicle speed that is steplessly changed according to the depression amount.

  The forward pedal 23 and the reverse pedal 24 are configured to move up and down alternately in conjunction with each other. That is, when the forward pedal 23 is depressed (lowered), the reverse pedal 24 rises in conjunction with this. Conversely, when the reverse pedal 24 is depressed, the forward pedal 23 is raised in conjunction with this. Further, when the foot is released from the forward pedal 23 and the reverse pedal 24 (when the operation force is released), the forward pedal 23 and the reverse pedal 24 are returned to the neutral position, and the traveling machine body 2 is stopped. .

  The interlocking mechanism and the neutral return mechanism of the forward pedal 23 and the reverse pedal 24 will be described in detail later.

  The hand accelerator lever 30 is configured so that the number of revolutions of the engine 5 can be adjusted by an operator's hand operation. That is, at the time of work in the field, it is necessary to make the rotational speed of the engine 5 substantially constant regardless of the traveling speed of the traveling machine body 2 in order to drive the working machine stably and without unevenness. Therefore, in the tractor 1 of the present embodiment, a hand accelerator lever 30 for adjusting the rotational speed of the engine 5 is provided in addition to the pedals 23 and 24 for adjusting the traveling speed.

  On the other hand, when the rotational speed of the engine 5 is always maintained at the rated rotational speed during non-working, it is not only efficient, but also causes noise and vibration. Therefore, it is preferable to change the rotational speed of the engine 5 as appropriate according to the traveling speed during non-working such as traveling on the road. However, if the operator has to finely adjust the hand accelerator lever 30 according to the traveling speed, the operation burden is large and inconvenient. Therefore, the tractor 1 of the present embodiment is configured such that the rotational speed of the engine 5 can be changed in conjunction with the operation amounts of the forward pedal 23 and the reverse pedal 24.

  Switching between interlocking / non-interlocking between the operation of the pedals 23 and 24 and the rotational speed of the engine 5 is performed by operating an operation lever (operation tool) 45 protruding from the step plate 12 into the cabin. That is, when the operation lever 45 is pulled upward, the pedals 23 and 24 and the rotational speed of the engine 5 are not linked, and the rotational speed of the engine 5 is substantially constant regardless of the amount of operation of the pedals 23 and 24. Therefore, the work machine can be driven stably and without unevenness. On the other hand, when the operation lever 45 is pushed down, the pedals 23 and 24 and the rotational speed of the engine 5 are linked to each other so that the rotational speed of the engine 5 is changed according to the operation amount of the pedals 23 and 24. Therefore, it is excellent from the viewpoint of prevention of noise and vibration and improvement of fuel consumption, and at the same time, an operation like a so-called automatic vehicle can be realized.

  In addition, about the structure for changing the rotational speed of the engine 5 in conjunction with the operation of the pedals 23 and 24, and the structure for switching the interlocking / non-interlocking between the rotational speed of the engine 5 and the operations of the pedals 23 and 24 Will be described in detail later.

  Next, a driving force transmission mechanism for performing a stepless speed change of the traveling speed of the traveling machine body 2 and a forward / reverse switching will be described. First, the internal structure of the mission case 17 will be described with reference to the skeleton diagram of FIG. The tractor 1 also includes a PTO transmission mechanism for shifting and transmitting the driving force of the engine 5 to a PTO shaft (not shown), but is omitted in FIG.

  As shown in FIG. 3, the mission case 17 includes a main transmission input shaft 27 for inputting power from the engine 5. The main transmission input shaft 27 is connected to a flywheel 25 provided in the engine 5 by an extendable power transmission shaft 28 provided with a universal shaft joint.

  The transmission case 17 appropriately shifts the rotation of the engine 5 transmitted to the main transmission input shaft 27 by a hydrostatic continuously variable transmission 29 that is a traveling main transmission mechanism. Then, the shifted output rotation is transmitted to the differential gear mechanism 58 for the rear wheels, and the left and right rear wheels 4 are driven. The rotated rotation is transmitted to the differential gear mechanism 86 for the front wheels, and the left and right front wheels 3 can be driven.

  As shown in FIG. 3, the continuously variable transmission 29 includes the main transmission input shaft 27 and a cylindrical main transmission output shaft 36 disposed radially outside the main transmission input shaft 27. It is configured as a so-called inline type HST. The main transmission output shaft 36 is arranged with the main transmission input shaft 27 aligned with the axis. Further, main transmission output gears 37 and 39 are fixed to the main transmission output shaft 36. The detailed configuration of the continuously variable transmission 29 will be described later.

  In the mission case 17, a travel counter shaft 38 and a reverse shaft (not shown) are arranged. A forward gear 41 and a reverse gear 43 are rotatably supported on the travel counter shaft 38, respectively. A reverse gear 44 is rotatably supported on the reverse shaft.

  The forward gear 41 and the travel counter shaft 38 can be connected by the forward clutch 40. Further, the reverse gear 43 and the travel counter shaft 38 can be connected by a reverse clutch 42. The forward gear 41 is in mesh with the main transmission output gear 37. The reverse gear 43 meshes with the reverse gear 44, and the reverse gear 44 meshes with the main transmission output gear 39.

  And in the tractor 1 of this embodiment, it is comprised so that the action | operation of the clutches 40 and 42 may be switched by operation of the forward pedal 23 and the reverse pedal 24. FIG. That is, when the operator depresses the forward pedal 23, the forward clutch 40 is connected and the reverse clutch 42 is disconnected, whereby the main transmission output gear 37 and the travel counter shaft 38 are connected by the forward gear 41. . On the other hand, when the reverse pedal 24 is depressed, the reverse clutch 42 is connected and the forward clutch 40 is disengaged, so that the main transmission output gear 39 and the travel counter shaft 38 move the reverse gear 43 and the reverse gear 44. Connected through.

  With the above configuration, the rotation direction of the travel counter shaft 38 can be switched in accordance with the operation of the forward pedal 23 and the reverse pedal 24, and the traveling machine body 2 can be moved forward and backward.

  When the forward pedal 23 and the reverse pedal 24 are set to the neutral position, both the clutches 40 and 42 are disconnected so that the traveling driving force is not transmitted downstream.

  A drive transmission gear 51 is fixed to the travel counter shaft 38. A traveling output shaft 50 is disposed in the mission case 17, and a drive input gear 52 is fixed to the traveling output shaft 50. The drive transmission gear 51 and the drive input gear 52 are engaged with each other, whereby the rotational driving force of the travel counter shaft 38 is transmitted to the travel output shaft 50.

  A pinion 59 is provided at the rear end portion of the travel output shaft 50, and a driving force is transmitted to the differential gear mechanism 58 for the rear wheels via the pinion 59. The differential gear mechanism 58 for the rear wheels includes a pair of left and right differential output shafts 62. The differential output shaft 62 is connected to the rear axle 64 via a final gear 63 and the like. With the above configuration, the traveling driving force is transmitted from the differential output shaft 62 to the rear axle 64, and the left and right rear wheels 4 can be driven.

  On the other hand, a gear 70 is provided at the front end of the traveling output shaft 50, and the traveling driving force transmitted to the gear 70 is input to the front wheel driving gear 75 via the gear 71, the front wheel input shaft 72, and the gear 78. Is done. The front wheel drive gear 75 is rotatably supported on the front wheel output shaft 73. The front wheel drive gear 75 can be connected to the front wheel output shaft 73 by a front wheel drive clutch 74.

  When a switching lever or switch (not shown) for switching between four-wheel drive and two-wheel drive is operated to the “four-wheel drive” position, the front-wheel drive clutch 74 is connected. As a result, the front wheel input shaft 72 and the front wheel output shaft 73 are connected by the front wheel drive gear 75, and the front wheel 3 is driven together with the rear wheel 4. On the other hand, when the changeover lever (or changeover switch) is operated to the “two-wheel drive” position, the front wheel drive clutch 74 is disconnected and the front wheel 3 is not driven.

  When the front-wheel drive clutch 74 is connected (when four-wheel drive is used), the rotational driving force of the front-wheel input shaft 72 is transmitted to the front-wheel differential gear mechanism 86 via the front-wheel output shaft 73. The differential gear mechanism 86 for the front wheels includes a pair of left and right differential output shafts 90, and the differential output shaft 90 is connected to the front axle 92 via a final gear 91 and the like. With the above configuration, the traveling driving force is transmitted from the differential output shaft 90 to the front axle 92, and the left and right front wheels 3 can be driven.

  Next, a detailed configuration of the continuously variable transmission 29 will be described with reference to FIG. FIG. 4 is a cross-sectional view of the vicinity of the continuously variable transmission 29.

  As shown in FIG. 4, the continuously variable transmission 29 includes a variable displacement hydraulic pump unit 501 and a constant displacement hydraulic motor unit 502. A common cylinder block 505 used in the hydraulic pump unit 501 and the hydraulic motor unit 502 is fixed to the middle part of the main transmission input shaft 27 in the longitudinal direction. A hydraulic pump unit 501 is disposed on one side in the longitudinal direction of the main transmission input shaft 27 as viewed from the cylinder block 505, and a hydraulic motor unit 502 is disposed on the other side.

  The hydraulic pump unit 501 includes a first holder 510, a movable pump swash plate 509, a plurality of shoes 508, and a plurality of pump plungers 506.

  The first holder 510 is fixed inside the mission case 17 so as to face the cylinder block 505 in the axial direction. The pump swash plate 509 is supported by the first holder 510 so that the inclination angle with respect to the axis of the main transmission input shaft 27 can be changed. A swash plate operation cylinder 556 is connected to the pump swash plate 509, and the tilt angle of the pump swash plate 509 can be changed by driving the swash plate operation cylinder 556.

  A plurality of shoes 508 are arranged on the pump swash plate 509, and each of them is configured to be slidable with respect to the pump swash plate 509. Each pump plunger 506 is slidably inserted into a first plunger hole 507 formed in the cylinder block 505. The head of the pump plunger 506 is connected to the shoe 508 via a spherical universal joint.

  The cylinder block 505 is provided with the same number of first spool valves 536 as the pump plungers 506. The first spool valve 536 is slidably fitted to a penetrating first valve hole 532 formed in the cylinder block 505 in the axial direction. The center portion of the first valve hole 532 communicates with the first plunger hole 507. Further, a ring-shaped first spool guide member 537 is fixed to the first holder 510. The first spool guide member 537 is disposed on the outer peripheral side of the main transmission input shaft 27, and an annular groove for engaging the head of the first spool valve 536 is formed on the outer peripheral surface. Yes.

  The ring-shaped first spool guide member 537 is arranged such that its axial direction is slightly inclined from the axis of the main transmission input shaft 27. Accordingly, since the annular groove on the outer periphery is also inclined, the first spool valve 536 reciprocates in the first valve hole 532 in the axial direction as the cylinder block 505 rotates.

  The hydraulic motor unit 502 includes a second holder 519, a motor swash plate 518, a plurality of shoes 517, and a plurality of motor plungers 515.

  The second holder 519 is rotatably supported with respect to the main transmission input shaft 27 so as to face the cylinder block 505 in the axial direction. The second holder 519 is fixed to the main transmission output shaft 36. The motor swash plate 518 is attached to the second holder 519 so that the inclination angle with respect to the axis of the main transmission input shaft 27 is constant.

  A plurality of shoes 517 are arranged on the motor swash plate 518, and each is configured to be slidable with respect to the motor swash plate 518. Each motor plunger 515 is slidably inserted into a second plunger hole 516 formed in the cylinder block 505. The head of the motor plunger 515 is connected to the shoe 517 through a spherical universal joint.

  The cylinder block 505 is provided with the same number of second spool valves 540 as the motor plungers 515. The second spool valve 540 is slidably fitted into a penetrating second valve hole 533 formed in the cylinder block 505 in the axial direction. The center portion of the second valve hole 533 communicates with the second plunger hole 516. A ring-shaped second spool guide member 541 is attached to the second holder 519. The second spool guide member 541 is disposed on the outer peripheral side of the main transmission input shaft 27, and an annular groove for engaging the head of the second spool valve 540 is formed on the outer peripheral surface. Yes.

  Similar to the first spool guide member 537, the ring-shaped second spool guide member 541 is arranged such that its axial direction is slightly inclined from the axis of the main transmission input shaft 27. Accordingly, since the annular groove on the outer periphery is also inclined, the second spool valve 540 moves in the second valve hole 533 (in conjunction with the first spool valve 536) as the cylinder block 505 rotates. Reciprocates in the axial direction.

  A first oil chamber 530 and a second oil chamber 531 are formed in the cylinder block 505, respectively. The first oil chamber 530 and the second oil chamber 531 are both formed in an annular shape and are arranged on the outer peripheral side of the main transmission input shaft 27. The first oil chamber 530 and the second oil chamber 531 both communicate with the first plunger hole 507 through the first valve hole 532 and communicate with the second plunger hole 516 through the second valve hole 533. is doing.

  With the above configuration, when the cylinder block 505 makes one rotation, the first spool valve 536 reciprocates once by the action of the first spool guide member 537, and the first plunger hole 507 moves into the first oil chamber 530 or the second oil chamber 531. It is designed to communicate alternately. At the same time, the second spool valve 540 reciprocates once by the action of the second spool guide member 541 so that the second plunger hole 516 communicates with the first oil chamber 530 or the second oil chamber 531 alternately. . The oil chamber in which the plunger holes 507 and 516 communicate with each other is switched between the first oil chamber 530 and the second oil chamber 531 every time the cylinder block 505 rotates 180 °.

  In FIG. 4, the pump plunger 506, the first plunger hole 507, the shoe 508, the first valve hole 532, the first spool valve 536, the motor plunger 515, the second plunger hole 516, the second valve hole 533, and the second Only one spool valve 540 or the like is illustrated for convenience of drawing, but in reality, a plurality of the above-described components and the like are arranged around the main transmission input shaft 27.

  Next, the operation of the continuously variable transmission 29 described above will be described in detail.

  First, the case where the pump swash plate 509 is substantially orthogonal to the axis of the main transmission input shaft 27 will be described. In this case, even if the cylinder block 505 is rotated by the power transmitted to the main transmission input shaft 27, the pump plunger 506 does not reciprocate. Accordingly, since the motor plunger 515 does not reciprocate, the motor swash plate 518 rotates integrally with the cylinder block 505. Accordingly, the rotational speed of the main transmission input shaft 27 is transmitted to the main transmission output shaft 36 without being changed.

  Next, the case where the pump swash plate 509 is inclined to one side with respect to the axis line of the main transmission input shaft 27 will be described. In this case, since the pump plunger 506 reciprocates according to the rotation of the cylinder block 505, the suction and discharge of the hydraulic oil in the first plunger hole 507 is repeatedly performed. The first hydraulic valve 536 and the second spool valve 540 are appropriately operated between the first plunger hole 507 and the second plunger hole 516, so that the closed hydraulic circuit is connected to the first oil chamber 530 or the second oil valve 530. It is formed through the oil chamber 531. Accordingly, hydraulic oil is pumped from the first plunger hole 507 to the second plunger hole 516 during the discharge stroke of the pump plunger 506, and hydraulic oil is returned in the reverse direction during the suction stroke of the pump plunger 506. Thus, the operations of the axial piston pump and the axial piston motor are performed.

  Therefore, when the pump swash plate 509 is tilted, the rotational speed of the hydraulic motor unit 502 driven by the hydraulic pump unit 501 is added to or subtracted from the rotational speed of the main transmission input shaft 27 to the main transmission output shaft 36. Communicated. With the above operation, the continuously variable speed rotation can be obtained at the main transmission output shaft 36.

  As described above, the inclination angle of the pump swash plate 509 is changed by driving the swash plate operation cylinder 556. And in the tractor 1 of this embodiment, the said swash plate operation cylinder 556 is comprised so that it may drive according to the control signal from the below-mentioned vehicle body controller. The vehicle body controller is configured to generate the control signal in accordance with the depression amount (operation amount) of the forward pedal 23 and the reverse pedal 24 and transmit the control signal to the swash plate operation cylinder 556. Thereby, the inclination angle of the pump swash plate 509 can be changed by the forward pedal 23 or the reverse pedal 24, and the traveling speed of the traveling machine body 2 can be changed intuitively and continuously.

  When the forward pedal 23 and the reverse pedal 24 are in the neutral position, the rotation of the main transmission input shaft 27 is completely canceled by setting the pump swash plate 509 to a predetermined inclination angle, and the vehicle speed is zero (stopped). It is configured as follows.

  The clutch swash plate 509 is connected to the clutch pedal 57 via a mechanical coupling mechanism (not shown). By depressing the clutch pedal 57, the inclination angle of the pump swash plate 509 is forcibly set. The predetermined inclination angle can be set. As a result, the rotation of the main transmission input shaft 27 can be completely canceled by depressing the clutch pedal 57. For example, when the vehicle body controller breaks down and the control of the swash plate operation cylinder 556 occurs. Also, the vehicle speed can be forcibly set to a zero state (stopped state).

  Next, the forward / reverse pedal unit 10 provided in the tractor 1 of the present embodiment will be described. The forward / reverse pedal unit 10 is a unit in which configurations relating to the forward pedal arm 21 and the reverse pedal arm 22 are combined.

  An external perspective view of the forward / reverse pedal unit 10 is shown in FIG. A right side view of the forward / reverse pedal unit 10 is shown in FIG. 6, a left side view is shown in FIG. 7, and an exploded perspective view is shown in FIG.

  As shown in FIGS. 5 to 7, the forward / reverse pedal unit 10 includes pedal arms 21 and 22, a pedal bracket (support member) 31, a pedal link member 32, a neutral return mechanism 33, and a potentiometer (detector). 34.

  As shown in FIG. 5, the pedal bracket 31 is formed by being bent at a substantially right angle to form a substantially vertical flat plate portion (arm mounting portion 31a) and a substantially horizontal flat plate portion (steps). Mounting portion 31b). As shown in FIG. 5 and the like, pedal arms 21 and 22 are attached to the left and right side surfaces of the arm attachment portion 31a. Further, as shown in FIGS. 6 and 7, the upper surface of the step attachment portion 31 b is fixed to the bottom surface of the step plate 12.

  Thus, the role of the pedal bracket 31 to support each component of the forward / reverse pedal unit 10 and the role of a member for attaching the forward / reverse pedal unit 10 to the vehicle body side (step plate 12) of the tractor 1 , Also. Thereby, the forward / reverse pedal unit 10 can be configured compactly. Further, since the forward / reverse pedal unit 10 can be handled as a unit, the workability when the forward / reverse pedal unit 10 is attached to the step plate 12 is improved.

  As shown in the right side view of FIG. 6, the forward pedal arm 21 is disposed such that the longitudinal direction is directed obliquely forward and upward. A forward pedal 23 is attached to the upper end of the forward pedal arm 21, and a first connecting portion 21b is provided at the lower end. Further, a rotation center portion 21 a of the forward pedal arm 21 is provided at an intermediate portion in the longitudinal direction of the forward pedal arm 21.

  Further, as shown in the left side view of FIG. 7, the reverse pedal arm 22 is also arranged so that the longitudinal direction is obliquely forward upward. A reverse pedal 24 is attached to the upper end of the reverse pedal arm 22, and a rotation center portion 22 a of the reverse pedal arm 22 is provided at the lower end. Further, a second connecting portion 22 b is provided at an intermediate portion in the longitudinal direction of the reverse pedal arm 22.

  Next, a configuration for supporting the pedal arms 21 and 22 with respect to the pedal bracket 31 will be described. In the tractor 1 of the present embodiment, the forward pedal arm 21 is cantilevered on one side of the arm attachment portion 31a, and the reverse pedal arm 22 is cantilevered on the other side of the arm attachment portion 31a.

  In other words, if both pedal arms 21 and 22 are supported on one side of the pedal bracket 31, an offset must be provided between the pedal arms 21 and 22 in order to avoid interference between the pedals 23 and 24. . In this case, in order to secure the offset, the shaft portion for supporting either one of the pedal arms 21 and 22 on the pedal bracket 31 becomes long, which causes a problem in strength and enlarges the pedal bracket. There is a problem. In this respect, in this embodiment, the pedal bracket 31 is compactly configured by distributing the pedal arms 21 and 22 to one side and the other side of the arm attachment portion 31a and supporting them in a cantilever manner as described above. be able to.

  Specifically, a boss portion is provided on one of the pedal arms 21 and 22 and the pedal bracket 31, and a round bar-shaped rotation shaft is provided on the other. And it is the structure which cantilever-supports the pedal arms 21 and 22 by inserting the said rotating shaft in the said boss | hub part. For example, in the present embodiment, as shown in FIG. 8, the rotation center portion 21a of the forward pedal arm 21 is formed as a round bar-shaped rotation shaft. On the other hand, the 1st support part 31c which protrudes in the boss shape is formed in one side of the arm attachment part 31a. The forward pedal arm 21 can be rotated with respect to the pedal bracket 31 by inserting the rotation center portion 21a into the insertion hole inside the boss-shaped first support portion 31c from the side from which the boss protrudes. Can be supported.

  As shown in FIG. 8, in the arm attachment portion 31a, a second support portion 31d protruding in a round bar shape is provided on the surface opposite to the surface on which the first support portion 31c is formed. . On the other hand, the rotation center portion 22a of the reverse pedal arm 22 is formed in a boss shape. Then, by inserting the second support portion 31d configured as a round rod-shaped rotation shaft into the insertion hole inside the boss from the side from which the boss-shaped rotation center portion 22a protrudes, the reverse pedal arm 22 is moved. The pedal bracket 31 can be rotatably supported.

  Next, a configuration in which the forward pedal arm 21 and the reverse pedal arm 22 are connected by the pedal link member 32 will be described.

  As shown in FIG. 8, the pedal link member 32 is configured as a round bar-like member that is appropriately bent, and includes a first end portion 32a, a link portion 32b, and a second end portion 32c. Yes. On the other hand, the connecting portion 21b provided on the pedal arm 21 is formed as a cylindrical portion into which a round bar-like pedal link member 32 can be inserted. The connecting portion 22b provided in the reverse pedal arm 22 is formed as an insertion hole into which the pedal link member 32 can be inserted.

  Then, the pedal link member 32 is attached to the forward pedal arm 21 so as to be rotatable around the first connecting portion 21b by inserting the first end portion 32a into the first connecting portion 21b. It has been. Similarly, by inserting the second end portion 32c into the second connecting portion 22b, the pedal link member 32 can be rotated around the second connecting portion 22b with respect to the reverse pedal arm 22. It is attached.

  In order to prevent the shaft when the pedal link member 32 rotates with respect to the forward pedal arm 21 from being shaken, the first connecting portion 21b is formed as an elongated cylindrical portion as shown in FIG.

  With the above configuration, the forward pedal arm 21 and the reverse pedal arm 22 are connected via a link mechanism including the link portion 32b of the pedal link member 32. Thereby, the forward pedal 23 and the reverse pedal 24 can be interlocked. Hereinafter, a state in which the forward pedal 23 and the reverse pedal 24 are interlocked will be described with reference to FIGS. 7, 9, and 10. 7 is a left side view showing the state when the forward pedal 23 and the reverse pedal 24 are in the neutral position, FIG. 9 is a left side view showing the state when the forward pedal 23 is depressed, and FIG. It is a left view which shows a mode when stepping on.

  A state when the forward pedal 23 is depressed will be described. In the forward pedal arm 21, when considered in the longitudinal direction of the forward pedal arm 21, a first connecting portion 21 b is provided on the opposite side of the forward pedal 23 when viewed from the rotation center portion 21 a. Accordingly, when the forward pedal 23 is depressed (ie, the forward pedal 23 is lowered) as shown in FIG. 9 from the neutral position shown in FIG. 7, the forward pedal arm 21 is centered on the rotation center portion 21a. As a result of the rotation, the first connecting portion 21b moves upward about the rotation center portion 21a.

  Here, since the 1st connection part 21b and the 2nd connection part 22b are connected via the pedal link member 32, if the 1st connection part 21b moves upwards, the 2nd connection part will be carried out by the pedal link member 32. 22b is pushed upward. On the other hand, when the reverse pedal arm 22 is considered in the longitudinal direction of the reverse pedal arm 22, the reverse pedal 24 and the second connecting portion 22b are provided on the same side as viewed from the rotation center portion 22a. Therefore, when the second connecting portion 22b is pushed upward by the pedal link member 32, the reverse pedal 24 also moves upward about the rotation center portion 22a (state of FIG. 9).

  On the other hand, when the reverse pedal 24 is depressed, the forward pedal 23 is raised contrary to the above case. That is, when the reverse pedal 24 is depressed from the neutral position in FIG. 7, the second connecting portion 22b moves downward about the rotation center portion 22a. Therefore, as a result of being pushed down by the pedal link member 32 and the first connecting portion 21b also moving downward, the forward pedal 23 moves upward about the rotation center portion 21a (state of FIG. 10).

  As described above, with a simple configuration in which the forward pedal arm 21 and the reverse pedal arm 22 are connected by the pedal link member 32, a mechanism for alternately moving the forward pedal 23 and the reverse pedal 24 up and down is realized. be able to.

  Next, a configuration for detecting the depression amount (operation amount) of the forward pedal 23 and the reverse pedal 24 will be described.

  In the tractor 1 of the present embodiment, the operation amount is electrically detected by the potentiometer 34. The configuration for shifting the vehicle speed in accordance with the pedal depression amount can be achieved, for example, by connecting the pump swash plate 509 of the continuously variable transmission 29 and the pedal arms 21 and 22 with a mechanical link mechanism or the like. Can be realized. However, as shown in FIG. 1, the pedals 23 and 24 are arranged at the front part in the cabin 7, while the transmission case 17 having the continuously variable transmission 29 inside is arranged at the rear part of the vehicle body. Therefore, when the continuously variable transmission 29 and the pedal arms 21 and 22 are connected by a mechanical link mechanism or the like, the link mechanism must be long, and the installation work of the link mechanism becomes complicated. The mounting property of the forward / reverse pedal unit 10 is deteriorated. In this regard, in the embodiment, by adopting a configuration in which the operation amount is electrically detected by the potentiometer 34, the mechanical connection structure is reduced, and the mounting property of the forward / reverse pedal unit 10 is improved. This will be specifically described below.

  As described above, the first support portion 31c is formed in a boss shape (see FIG. 8). The insertion hole inside the boss-shaped first support portion 31c is formed in a penetrating manner, and communicates the space on one side in the thickness direction of the arm mounting portion 31a with the space on the other side. And if the round bar-shaped rotation center part 21a is inserted in the said insertion hole, the front-end | tip part of the said rotation center part 21a will be protruded to the other surface side of the arm attachment part 31a.

  On the other hand, as shown in FIGS. 5 and 7, an auxiliary bracket 35 is disposed on the surface of the arm attachment portion 31a opposite to the surface on which the first support portion 31c is formed. A potentiometer 34 is fixed to the auxiliary bracket 35.

  The potentiometer 34 is inserted into the boss of the first support portion 31c and attached to the tip end portion of the rotation center portion 21a protruding from the opposite surface, and electrically detects the amount of rotation of the rotation center portion 21a. It is configured as follows. With the above configuration, the rotation amount of the forward pedal arm 21 can be electrically detected with a simple configuration.

  Further, as described above, in this embodiment, the forward pedal 23 and the reverse pedal 24 are interlocked, and therefore, the operation amount of both the forward pedal 23 and the reverse pedal 24 is electrically detected by one potentiometer 34. be able to. For example, in the left side view of FIG. 7, when the potentiometer 34 detects that the rotation center portion 21a has rotated clockwise from the state of the neutral position shown in FIG. 7, it can be seen that the forward pedal 23 has been depressed. A clockwise rotation amount is detected as an operation amount of the forward pedal 23. On the other hand, when the potentiometer 34 detects that the rotation center portion 21a has rotated counterclockwise from the neutral position in FIG. 7, it can be determined that the reverse pedal 24 has been depressed, and therefore the counterclockwise rotation amount is reversed. It is detected as an operation amount of the pedal 24.

  As described above, it is possible to obtain information regarding which of the forward pedal 23 or the reverse pedal 24 is depressed and the amount of depression (operation amount) of the forward pedal 23 or the reverse pedal 24 by one potentiometer 34.

  On the other hand, the tractor 1 of this embodiment includes a vehicle body controller (not shown). The vehicle body controller is configured as a microcontroller, for example. The detection value of the potentiometer 34 is configured to be transmitted to the vehicle body controller. Then, the vehicle body controller determines from the detection value of the potentiometer 34 whether the forward pedal 23 or the reverse pedal 24 is depressed, and switches the forward clutch 40 and the reverse clutch 42 based on the determination result. . Thus, the forward and reverse travel of the traveling machine body 2 can be switched by operating the forward pedal 23 and the reverse pedal 24.

  The vehicle body controller transmits a control signal for operating the swash plate operating cylinder 556 based on the depression amount of the forward pedal 23 or the reverse pedal 24 obtained from the detection value of the potentiometer 34. Based on this control signal, the swash plate operating cylinder 556 is driven, and the tilt angle of the pump swash plate 509 is adjusted. With the above configuration, by operating the forward pedal 23 and the reverse pedal 24, the traveling speed of the traveling machine body 2 can be changed steplessly.

  Next, the neutral return mechanism 33 included in the forward / reverse pedal unit 10 will be described with reference to FIGS. 6, 11, and 12. 6 is a right side view showing the state when the forward pedal 23 and the reverse pedal 24 are in the neutral position, FIG. 11 is a right side view showing the state when the forward pedal 23 is depressed, and FIG. It is a right view which shows a mode when stepping on.

  The neutral return mechanism 33 includes a neutral return arm (first arm member) 53, a neutral return roller 54, and an urging spring 55.

  The neutral return arm 53 has a roller support shaft 53a, and the neutral return roller 54 is rotatably attached to the roller support shaft 53a. On the other hand, a neutral return arm support portion 31e protruding in a round bar shape is disposed on the surface of the arm mounting portion 31a of the pedal bracket 31 where the first support portion 31c is formed (see FIG. 8). reference). The neutral return arm 53 is rotatably supported with respect to the neutral return arm support portion 31e.

  With the above configuration, the neutral return roller 54 is rotatable about the neutral return arm support portion 31e. The plane on which the neutral return roller 54 rotates about the neutral return arm support portion 31e is configured to substantially coincide with the plane on which the forward pedal arm 21 rotates about the rotation center portion 21a. ing. Thereby, the neutral return roller 54 can come into contact with the cam surface 21 d formed on the forward pedal arm 21.

  Further, the biasing spring 55 is configured as a tension coil spring, and is arranged so as to connect the neutral return arm 53 and the auxiliary bracket 35 as shown in FIGS. The biasing spring 55 applies a biasing force that causes the neutral return arm 53 to rotate in a predetermined direction around the neutral return arm support portion 31e. The urging force causes the neutral return roller 54 supported by the neutral return arm 53 to be pressed against the cam surface 21d of the forward pedal arm 21.

  On the other hand, in the forward pedal arm 21, a concave portion 21c that is concave in the direction in which the neutral return roller 54 is urged (concave toward the rotation center portion 21a) is provided at the substantially central portion of the cam surface 21d. Is formed. The recess 21c is formed smoothly and continuously with the surrounding cam surface 21d. When the forward pedal 23 and the reverse pedal 24 are in the neutral position (in the state shown in FIG. 6), a part of the neutral return roller 54 is configured to enter the recess 21c.

  Here, in the state in which the neutral return roller 54 is fitted in the concave portion 21c (the neutral position in FIG. 6), the position of the concave portion 21c and the position of the concave portion 21c are minimized so that the extension of the biasing spring 55 that is a tension coil spring is minimized. The position of the rotation center portion 21a is set as appropriate. With the neutral return mechanism 33 configured as described above, the forward pedal 23 and the reverse pedal 24 can be automatically returned to the neutral position.

  This will be specifically described below. For example, when the forward pedal 23 is depressed from the neutral position in FIG. 6, the forward pedal arm 21 rotates around the rotation center portion 21a. At this time, as shown in FIG. 11, since the cam surface 21d including the recess 21c moves around the rotation center 21a, the neutral return roller 54 is detached from the recess 21c, and the cam surface 21d moves the neutral return roller 54. Push. As a result, the neutral return arm 53 rotates against the urging force of the urging spring 55.

  Then, the urging spring 55 is extended, and the pressing force of the neutral return roller 54 against the forward pedal arm 21 is increased. As a result, a force for returning to the state where the pressing force of the neutral return roller 54 is the smallest (that is, the neutral position) acts on the forward pedal arm 21. Accordingly, when the foot is released from the forward pedal 23 (stopping the stepping operation), the forward pedal arm 21 automatically rotates to the neutral position.

  Also, as shown in FIG. 12, when the reverse pedal 24 is depressed, the neutral return arm 53 rotates against the biasing force of the biasing spring 55 in the same manner as described above, so that it returns to the neutral position. The acting force acts on the reverse pedal arm 22. Accordingly, when the foot is released from the reverse pedal 24, the reverse pedal arm 22 automatically rotates to the neutral position.

  As described above, the neutral return mechanism of the forward pedal 23 and the reverse pedal 24 can be realized with a simple configuration. The concave portion 21c holds the forward pedal 23 and the reverse pedal 24 so that they do not move from the neutral position to the extent that a small force is applied due to some bounce, and depresses the forward pedal 23 and the reverse pedal 24 from the neutral position. It also has the function of giving a moderate click feeling when operating with.

  Next, a configuration for adjusting the rotational speed of the engine 5 in conjunction with the operation amounts of the forward pedal 23 and the reverse pedal 24 will be described with reference to FIGS. FIG. 13 is an exploded perspective view of the accelerator interlocking switching mechanism 100. As shown in FIGS. 13 and 6, the accelerator interlocking switching mechanism 100 includes each configuration of the neutral return mechanism 33 (the neutral return arm 53 and the neutral return roller 54 described above) and an accelerator operation arm (second arm member). 65, a connecting plate 46, and an operation lever 45.

  As shown in FIG. 13, at one end in the longitudinal direction of the accelerator operation arm 65, a rotation center portion 65a formed in a hole shape is formed. By inserting the roller support shaft 53a through the rotation center portion 65a, the accelerator operation arm 65 is supported so as to be rotatable relative to the neutral return arm 53 around the roller support shaft 53a. On the other hand, a wire connection portion 65b is provided at the other longitudinal end of the accelerator operation arm 65, and an end portion of a first wire (first interlocking member) 66 is connected to the wire connection portion 65b.

  Next, a description will be given with reference to the schematic side view of FIG. As shown in FIG. 14, the other end of the first wire 66 is connected to an operating unit 80 described later. Further, as shown in FIG. 14, the operating portion 80 and the speed control lever 5 b provided in the governor device 5 a of the engine 5 are connected by a second wire (second interlocking member) 67. The speed control lever 5b is configured to change the rotational speed of the engine 5 by being rotated about a fulcrum. Then, by pulling the speed control lever 5b with the second wire 67 connected to the speed control lever 5b, the speed control lever 5b can be rotated.

  As shown in the side view of FIG. 14, the operating portion 80 is disposed in the vicinity of the hand accelerator lever 30. Here, since the hand accelerator lever 30 and the pedals 23 and 24 are operated by an operator sitting on the driver's seat 8, the position between the engine 5 and the driver's seat 8 in a plan view (just behind the engine 5). Is arranged. In other words, the engine 5, the hand accelerator lever 30, and the pedals 23 and 24 are arranged (intensively) in a relatively small range.

  Therefore, it is possible to effectively shorten the first wire 66 that connects the operating portion 80 disposed in the vicinity of the hand accelerator lever 30 and the accelerator operation arm 65 provided in the forward / reverse pedal unit 10. Further, the second wire 67 that connects the operating portion 80 disposed in the vicinity of the hand accelerator lever 30 and the speed control lever 5b included in the engine 5 can be shortened in the same manner as described above. The tractor 1 according to the present embodiment can shorten the first wire 66 and the second wire 67 in this way, and thus is excellent in attachment property and maintenance property of the wires 66 and 67.

  On the other hand, as shown in FIG. 13, the neutral return arm 53 is formed with a long hole (first insertion hole) 53c, and the accelerator operation arm 65 is formed with a long hole (second insertion hole) 65c. These long holes 53c and 65c are all formed in a penetrating shape. The long hole 53c and the long hole 65c are formed so that their positions overlap each other when the relative direction with respect to the neutral return arm 53 of the accelerator operation arm 65 becomes a predetermined direction. Then, in a state where the long hole 53c and the long hole 65c are overlapped with each other (facing each other), the accelerator operation arm 65 and the neutral return arm 53 are moved by inserting the convex portion 46b formed on the connecting plate 46 shown in FIG. It can be fixed so that it cannot rotate relative to each other. In addition, the structure of the connection plate 46 and the convex part 46b is mentioned later. Thus, the accelerator operation arm 65 is integrated with the neutral return arm 53 (so as not to rotate about the roller support shaft 53a), and rotates with the neutral return arm 53 around the neutral return arm support portion 31e. It has become.

  On the other hand, as described above, when the forward pedal 23 or the reverse pedal 24 is operated, the neutral return arm 53 rotates. Therefore, in a state where the neutral return arm 53 and the accelerator operation arm 65 are connected (a state where the convex portions 46b are inserted into the long holes 53c and 65c), the accelerator operation arm 65 is rotated by operating the pedals 23 and 24. (See FIGS. 11 and 12). 11 and 12, the first wire 66 is pulled by the wire connecting portion 65b as the pedals 23 and 24 are depressed.

  When the first wire 66 is pulled by the wire connecting portion 65b, the operating portion 80 (see FIG. 14) connected to the first wire 66 is operated (details will be described later). The 2-wire 67 pulls the speed control lever 5b of the governor device 5a. The governor device 5 a is configured to increase the rotational speed of the engine 5 in response to the speed control lever 5 b being pulled by the second wire 67.

  With the above configuration, when the forward pedal 23 or the reverse pedal 24 is depressed, the rotational speed of the engine 5 increases, and when the forward pedal 23 and the reverse pedal 24 are depressed (to return to the neutral position by the neutral return mechanism 33). The number of rotations decreases. Thereby, a so-called automatic car-like operation is realized. As described above, the cam surface 21d, the neutral return roller 54, the neutral return arm 53, and the like of the forward pedal arm 21 provide the operating force for the operator to operate the forward pedal 23 or the reverse pedal 24 (via the first wire 66). It can be said that it has a function of transmitting to the governor device 5a.

  On the other hand, the accelerator operation arm 65 can be rotated relative to the neutral return arm 53 by removing the projection 46b from the long hole 53c and the long hole 65c. With the projection 46b removed as described above, even if the neutral return arm 53 rotates in response to the rotation of the forward pedal arm 21, as shown in FIG. Hardly moves, the first wire 66 is not pulled. Therefore, the rotational speed of the engine 5 can be made substantially constant regardless of the operation amount of the forward pedal 23 or the reverse pedal 24, and the working machine connected to the PTO shaft (not shown) can be driven stably.

  Next, a configuration for switching between interlocking / non-interlocking between the operation of the forward pedal 23 and the reverse pedal 24 and the rotational speed of the engine 5 will be described with reference to FIGS. 13, 16, 17, and the like. 16 and 17 are schematic front sectional views mainly showing the accelerator interlocking switching mechanism 100. FIG.

  The connection plate 46 is formed of a metal plate, and a rotation center portion 46a is formed on the connection plate 46 as shown in FIG. On the other hand, a plate support part (fixing member support part) 53d that rotatably supports the connecting plate 46 is fixed to the neutral return arm 53. By supporting the rotation center portion 46a so as to be rotatable with respect to the plate support portion 53d, the connecting plate 46 can be rotated around the rotation center portion 46a.

  Further, as described above, the connecting plate 46 is formed with a convex portion 46b as shown in FIG. Then, when the connecting plate 46 rotates about the rotation center portion 46a, the convex portion 46b moves in an arc-like locus in a plane including the longitudinal direction of the long hole 53c. .

  Further, as described above, by setting the neutral return arm 53 and the accelerator operation arm 65 to a predetermined positional relationship, the long hole 53c formed in the neutral return arm 53 and the long hole formed in the accelerator operation arm 65 are provided. 65c can be in a state of facing each other. Then, when the connecting plate 46 is rotated to a predetermined position around the rotation center portion 46a, the convex portion 46b of the connecting plate 46 can be inserted into both the long holes 53c and 65c as shown in FIG. ing.

  And it can be set as the state (state of Drawing 11 and Drawing 12) where neutral return arm 53 and accelerator operation arm 65 were mutually fixed by setting it as the state where convex part 46b was inserted in long holes 53c and 65c. Thereby, since the first wire 66 can be operated by operating the pedals 23 and 24, the pedals 23 and 24 and the rotational speed of the engine 5 can be linked.

  On the other hand, when the connecting plate 46 is rotated by a predetermined angle from the state shown in FIG. 16, the projection 46b is removed from the long holes 53c and 65c, as shown in FIG. It can be set as the released state (the state of FIG. 15). Thereby, even if the pedals 23 and 24 are operated, the first wire 66 is not operated, so that the rotational speed of the engine 5 and the operations of the pedals 23 and 24 can be made unlinked.

  An operation lever 45 is connected to the connecting plate 46. By moving the operation lever 45 up and down, the connecting plate 46 can be rotated about the rotation center 46a.

  For example, in the present embodiment, as shown in FIG. 16, by pressing the operating lever 45 downward, the convex portion 46b can be inserted into the long holes 53c and 65c. On the other hand, as shown in FIG. 17, by setting the operation lever 45 upward, the convex portion 46b can be removed from the elongated holes 53c and 65c.

  With the above configuration, by operating the operation lever 45, the rotational speed of the engine 5 and the operation of the pedals 23, 24 are interlocked with each other, and the rotational speed of the engine 5 is substantially constant regardless of the operation of the pedals 23, 24. It is possible to switch between these states. As shown in FIGS. 2 and 7, the tip of the operation lever 45 protrudes above the step plate 12 and is exposed in the cabin 7. As a result, the operator can easily operate the connecting plate 46 from within the cabin 7.

  16 and 17, an urging spring 68 configured as a tension coil spring is provided between the base end portion of the operation lever 45 and the plate support portion 53d. The spring force of the urging spring 68 is such that the convex portion 46b is inserted into the long hole 53c and the long hole 65c (the state shown in FIG. 16), or the convex portion 46b is completely removed from the long holes 53c and 65c. In the state shown in FIG. 17, the rotation of the connecting plate 46 is maintained.

  In this configuration, when the operator tries to push down the operation lever 45 from the state shown in FIG. 16, the biasing spring 68 initially applies a spring force against it. However, when the operation lever 45 is operated against the spring force and the connecting plate 46 is rotated to some extent, the direction in which the spring force tries to rotate the connecting plate 46 is reversed by exceeding the fulcrum of the biasing spring 68. . As a result, after switching to the state of FIG. 17, the rotational position of the connecting plate 46 is held by the biasing spring 68. Note that the above-described action of the biasing spring 68 also works in the same way when the rotational position of the connecting plate 46 is switched from the state of FIG. 17 to the state of FIG.

  Next, a configuration for changing the rotational speed of the engine 5 by the hand accelerator lever 30 will be described with reference to FIGS. 18 is an exploded perspective view of the configuration in the vicinity of the hand accelerator lever 30, and FIG. 19 is a side view in the vicinity of the hand accelerator lever 30.

  As shown in FIG. 18, the hand accelerator lever 30 includes a handle portion 30b fixed to one end of the rotating shaft portion 30a, and an operating portion operation member 30c fixed to the other end of the rotating shaft portion 30a. . Further, the tractor 1 includes a first bracket 47 for supporting the hand accelerator lever 30. The rotation shaft portion 30a is attached to the first bracket 47 so as to be rotatable about the axis of the rotation shaft portion 30a. With the above configuration, the operating portion operating member 30c can be rotated by the operator rotating the handle portion 30b.

  On the other hand, a second bracket 48 is fixed below the first bracket 47. The second bracket 48 supports the operating unit 80 and the potentiometer 49.

  As shown in FIG. 18, the operating unit 80 includes a first operating member 93, a second operating member 94, and a rotating shaft 77. On the other hand, the second bracket 48 is formed with a boss-like operating portion support portion 48a. In addition, the insertion hole formed in the boss-like operating portion support portion 48 a is configured to penetrate the second bracket 48.

  Then, in a state where the first operating member 93 is fixed to one end side of the rotating shaft 77 so as not to rotate, the rotating shaft 77 is inserted into the insertion hole of the boss-shaped operating portion support portion 48a. Accordingly, the first operating member 93 is supported so as to be rotatable about the rotation shaft 77 with respect to the second bracket 48.

  The first operating member 93 is formed with a second wire connecting portion 93a. As shown in FIG. 19, the end portion of the second wire 67 is connected to the second wire connecting portion 93a. The first actuating member 93 is configured to be capable of pulling the second wire 67 by rotating the first actuating member 93 clockwise about the rotation shaft 77 in FIG. Yes.

  On the other hand, as described above, the other end of the second wire 67 is connected to the speed control lever 5b provided in the governor device 5a (see FIG. 14). With the above configuration, when the first actuating member 93 is rotated clockwise around the rotation shaft 77 in FIG. 19, the second wire 67 pulls the speed adjusting lever 5b to rotate, so that the engine 5 The number of rotations can be changed.

  As described above, the governor device 5a of the present embodiment is configured to rotate the engine 5 at a higher speed as the speed control lever 5b is pulled by the second wire 67. As the operating member 93 rotates clockwise, the engine 5 rotates at a higher speed. The first actuating member 93 is biased toward the low speed rotation side of the engine 5 by a spring member (not shown) (that is, in FIG. 19, the first actuating member 93 is counterclockwise about the rotation shaft 77). Is biased in the direction). The speed control lever 5b is urged toward the low-speed rotation side by a spring member (not shown). With the above configuration, when no operating force is applied to the first operating member 93, the first operating member 93 naturally rotates counterclockwise about the rotation shaft 77, and the engine 5 rotates at a low speed. Kept in a state.

  As shown in FIG. 18 etc., the 1st action | operation member 93 has the rod-shaped contact part 93b. On the other hand, a contact portion 30d is formed on the operating portion operation member 30c included in the hand accelerator lever 30. The contact portion 30 d passes through an arc-shaped through hole 47 a formed in the first bracket 47 and protrudes below the first bracket 47. Then, as shown in FIG. 19, the contact portion 30d on the hand accelerator lever 30 side is clockwise with respect to the contact portion 93b on the first operating member 93 side in the clockwise direction of FIG. It is comprised so that it may contact | abut from the upstream side.

  With the above configuration, when the hand accelerator lever 30 is rotated, the contact portion 30d on the hand accelerator lever 30 side presses the contact portion 93b of the first operating member 93, and the first operating member 93 is rotated. Can be made. Thereby, the rotational speed of the engine 5 can be adjusted by the hand accelerator lever 30. This will be specifically described below.

  The state of FIG. 19 is a state in which the first operating member 93 has rotated counterclockwise to the limit (in order to limit the rotation range of the first operating member 93, the first operating member 93 can contact the first operating member 93). A stopper 48b is formed on the second bracket 48). In this state, the second wire 67 is not pulled by the second wire connecting portion 93a, that is, the engine 5 is in a low-speed rotation state. At this time, the hand accelerator lever 30 is in the “low-speed rotation” position.

  FIG. 20 shows a state in which the operator rotates the hand accelerator lever to the “high-speed rotation” position from the state of FIG. When the hand accelerator lever is rotated from the “low speed rotation” position to the “high speed rotation” position, the contact portion 30d on the hand accelerator lever 30 side moves from left to right in FIG. Thereby, the contact part 93b by the side of the 1st action | operation member 93 is pushed by the said contact part 30d, and it is comprised so that the 1st action | operation member 93 may rotate clockwise. As a result, the second wire 67 is pulled by the second wire connecting portion 93a, and the second wire 67 pulls the governing lever 5b, so that the rotational speed of the engine 5 increases.

  On the other hand, when the hand accelerator lever 30 is turned to the “low speed rotation” position from the state shown in FIG. Move left from. As a result, the force by which the contact portion 30d pushes the contact portion 93b on the first operating member 93 side is released. As described above, since the first actuating member 93 is urged counterclockwise by an unillustrated urging spring, the first actuating member 93 rotates counterclockwise and naturally returns to its original position. Return. As a result, the force with which the second wire connecting portion 93a pulls the second wire 67 is released, so that the rotational speed of the engine 5 decreases.

  A friction plate 60 is disposed between the hand accelerator lever 30 and the first bracket 47, and a constant resistance torque is applied when the hand accelerator lever 30 is rotated by the frictional force of the friction plate 60. It has become so. The magnitude of the frictional force by the friction plate 60 is set so that the orientation of the hand accelerator lever 30 can be maintained regardless of the counterclockwise biasing force applied to the first actuating member 93. Thus, even if the hand accelerator lever 30 is released (the operation force applied to the hand accelerator lever 30 is released), the positions of the hand accelerator lever 30 and the first actuating member 93 are maintained. The speed can be kept constant.

  Next, a configuration in which the accelerator interlocking switching mechanism 100 included in the forward / reverse pedal unit 10 and the governor device 5a of the engine 5 are interlocked will be described in detail.

  The second actuating member 94 is supported by a rotating shaft 77 so as to be rotatable relative to the first actuating member 93. As shown in FIG. 18 and the like, the second actuating member 94 has a first wire connecting portion 94a, and an end portion of the first wire 66 is connected to the first wire connecting portion 94a. On the other hand, as described above, the other end portion of the first wire 66 is connected to the wire connection portion 65b of the accelerator operation arm 65 (see FIG. 6 and the like).

  As described above, when the operation lever 45 is in the depressed position (when the neutral return arm 53 and the accelerator operation arm 65 are fixed to each other by the connecting plate 46), the pedals 23 and 24 are depressed. Thus, the other end portion of the first wire 66 is pulled by the wire connection portion 65b. As a result, the first wire connecting portion 94 a of the second operating member 94 is pulled by the first wire 66. Thus, the second operating member 94 is configured to rotate clockwise in FIG. 19 about the rotation shaft 77.

  Further, as shown in FIG. 18, the second operating member 94 has a contact portion 94b. On the other hand, the first actuating member 93 is formed with a contact portion 93c that can contact the contact portion 94b from the downstream side in the clockwise direction of FIG. Accordingly, in the state where the contact portion 94b on the second operation member 94 side is in contact with the contact portion 93c on the first operation member 93 side, the second operation member 94 is centered on the rotation shaft 77 and the timepiece of FIG. When rotating in the rotating direction, the first operating member 93 can be driven to rotate clockwise by the contact portion 94b pushing the contact portion 93c.

  With the above configuration, when the pedals 23 and 24 are operated, the contact portion 94b on the second operation member 94 side pushes the contact portion 93c on the first operation member 93 side, and the first operation member 93 is rotated. Can be made. Thereby, the rotational speed of the engine 5 can be adjusted by operating the pedals 23 and 24. This will be specifically described below.

  The state of FIG. 19 corresponds to a neutral state (state of FIG. 6) in which the forward pedal 23 and the reverse pedal 24 are not operated. From this state, when the forward pedal 23 or the reverse pedal 24 is depressed by the operator (the state shown in FIG. 11 or 12), the first wire connecting portion 94a is pulled by the first wire 66, and the second operating member 94 is moved. It rotates clockwise in FIG. 19 about the rotation shaft 77. Accordingly, the contact portion 93c on the first operation member 93 side is pushed by the contact portion 94b on the second operation member side, and the first operation member 93 is rotated clockwise in FIG. It rotates (state of FIG. 21). Accordingly, the second wire 67 is pulled by the second wire connecting portion 93a, and the speed adjusting lever 5b is pulled by the second wire 67, so that the rotational speed of the engine 5 increases.

  On the other hand, when the stepping operation on the forward pedal 23 and the reverse pedal 24 is released from the state of FIG. 21, the first actuating member 93 rotates counterclockwise in FIG. To turn. Thereby, the rotational speed of the engine 5 decreases. At this time, the abutment portion 94b on the second actuation member 94 side is pushed by the abutment portion 93c on the first actuation member 93 side, so that the second actuation member 94 is shown in FIG. It rotates clockwise and returns to the state of FIG.

  As described above, the hand accelerator lever 30 and the pedals 23 and 24 are both connected to the speed control lever 5b via the operating portion 80. Thereby, the rotational speed of the engine 5 can be adjusted by both the hand accelerator lever 30 and the pedals 23 and 24. By the way, if the pedals 23 and 24 move with the operation of the hand accelerator lever 30 or the hand accelerator lever 30 moves with the operation of the pedals 23 and 24, a natural operation cannot be performed. In this respect, in the tractor 1 of the present embodiment, the hand accelerator lever 30 and the pedals 23 and 24 are prevented from moving in conjunction with each other by configuring the hand accelerator lever 30 and the operating portion 80 as described above. .

  Specifically, even if the hand accelerator lever 30 is rotated to the “high-speed rotation” side from the state of FIG. 19, the second actuating member 94 does not rotate as shown in FIG. 20. That is, even if the hand accelerator lever 30 is operated, the pedals 23 and 24 do not move in conjunction with each other. Further, even if the pedals 23 and 24 are depressed from the state of FIG. 19, the hand accelerator lever 30 does not rotate as shown in FIG. That is, even if the pedals 23 and 24 are operated, the hand accelerator lever 30 side does not move in conjunction.

  Next, the potentiometer 49 attached to the second bracket 48 will be described. As shown in FIG. 18, the potentiometer 49 is attached to the second bracket 48 from the side opposite to the side on which the operating portion 80 is attached. The potentiometer 49 is connected to the end of a rotating shaft 77 that is inserted through a boss-like operating portion support 48a. With the above configuration, the potentiometer 49 is configured to electrically detect the amount of rotation of the rotation shaft 77 (the amount of rotation of the first actuating member 93). Then, from the amount of rotation of the first actuating member 93, it is possible to know how much the second wire 67 has been pulled by the second wire connecting portion 93a, that is, how much the speed control lever 5b of the governor device 5a has been operated. . Therefore, by detecting the rotation amount of the first actuating member 93 by the potentiometer 49, the engine rotation speed (target rotation speed) corresponding to the operation position of the pedals 23, 24 or the hand accelerator lever 30 can be detected.

  The detection value of the potentiometer 49 is input to the vehicle body controller. The vehicle body controller obtains the target rotation speed based on the detection value of the potentiometer 49. Then, the vehicle body controller performs anti-stall control of the engine 5 based on the target rotational speed. Specifically, the vehicle body controller compares the actual rotational speed of the engine 5 with the target rotational speed obtained based on the detection value of the potentiometer 49, and calculates the load of the engine 5. Then, by driving the swash plate operation cylinder 556 of the continuously variable transmission 29 according to the calculated load, the load of the engine 5 is adjusted and the stall of the engine 5 is prevented.

  As described above, the tractor 1 according to the present embodiment includes the engine 5 disposed at the front portion of the vehicle body and the driver seat 8 disposed behind the engine 5. The tractor 1 includes a hand accelerator lever 30, an operating unit 80, pedals 23 and 24, a pedal bracket 31, and an accelerator interlocking switching mechanism 100. The hand accelerator lever 30 is disposed between the engine 5 and the driver seat 8 in a plan view. The operation unit 80 is disposed in the vicinity of the hand accelerator lever 30 and can be operated in conjunction with the operation of the hand accelerator lever 30. The pedals 23 and 24 are disposed between the engine 5 and the driver seat 8 in plan view. The pedal bracket 31 supports the pedal arms 21 and 22. The accelerator interlock switching mechanism 100 is supported by the pedal bracket 31. In addition, the operating unit 80 and the accelerator interlock switching mechanism 100 are connected by the first wire 66. The operating unit 80 and the governor device 5 a of the engine 5 are connected by a second wire 67. The accelerator interlocking switching mechanism 100 can switch between a state in which the pedals 23 and 24 and the first wire 66 are interlocked and a state in which the interlock is released.

  Thereby, by switching the presence or absence of the linkage between the pedals 23 and 24 and the first wire 66 by the accelerator linkage switching mechanism 100, the state where the pedals 23 and 24 and the governor device 5a of the engine 5 are linked, and the linkage is It is possible to switch between the released state and the released state. In addition, since the operating unit 80, the hand accelerator lever 30, the pedals 23 and 24, the accelerator interlocking switching mechanism 100, and the like are collectively arranged behind the engine 5, the first wire 66 and the second wire 67 are shortened. This makes it possible to assemble and maintain.

  Moreover, the tractor 1 of this embodiment is configured as follows. That is, the tractor 1 includes a continuously variable transmission 29 and a potentiometer 34. The continuously variable transmission 29 is disposed at the rear of the vehicle body and changes the output of the engine 5. The potentiometer 34 electrically detects the operation amount of the pedals 23 and 24. And based on the detection result of the potentiometer 34, the gear ratio of the continuously variable transmission 29 is changed.

  Thereby, according to operation of the pedals 23 and 24, a running speed can be steplessly changed. Further, since the pedals 23 and 24 are disposed in front of the driver's seat 8 and the continuously variable transmission 29 is disposed at the rear of the vehicle body, the pedals 23 and 24 and the continuously variable transmission 29 are temporarily connected to the machine. If it is set as the structure which connects automatically, the said mechanical connection mechanism will become long. In this respect, by adopting a configuration in which the operation amounts of the pedals 23 and 24 are electrically detected as described above, the mechanical connection mechanism can be omitted, and the assemblability and maintainability can be further improved.

  Moreover, the tractor 1 of this embodiment is configured as follows. That is, the accelerator interlocking switching mechanism 100 includes a neutral return arm 53, an accelerator operation arm 65, and a connection plate 46. The neutral return arm 53 operates in conjunction with the pedals 23 and 24. The accelerator operation arm 65 is connected to the first wire 66 and is configured to be rotatable relative to the neutral return arm 53. The connection plate 46 can be switched between a state in which the neutral return arm 53 and the accelerator operation arm 65 are fixed to each other and a state in which the fixation is released.

  That is, the neutral return arm 53 and the accelerator operation arm 65 are fixed to each other by the connecting plate 46, whereby the pedals 23 and 24 and the first wire 66 are interlocked. Further, the first wire 66 is interlocked with the governor device 5 a of the engine 5 through the operating portion 80 and the second wire 67. Therefore, by fixing the neutral return arm 53 and the accelerator operation arm 65 to each other by the connecting plate 46, the pedals 23 and 24 and the governor device 5a of the engine 5 can be interlocked. Thereby, the rotation speed of the engine 5 can be changed by operating the pedals 23 and 24. On the other hand, by releasing the fixation of the neutral return arm 53 and the accelerator operation arm 65 by the connecting plate 46, the linkage between the pedals 23 and 24 and the governor device 5a is released. As described above, it is possible to switch the presence / absence of the linkage between the pedals 23 and 24 and the rotational speed of the engine 5 with a simple configuration.

  Moreover, the tractor 1 of this embodiment is configured as follows. That is, the pedal bracket 31 is attached to the step plate 12 from the lower surface side of the step plate 12 of the driver seat. The accelerator interlock switching mechanism 100 includes an operation lever 45 exposed above the step plate 12. The operation lever 45 can be used to switch between fixing and releasing the neutral return arm 53 and the accelerator operation arm 65 by the connecting plate 46.

  As a result, the operator can operate the connecting plate 46 with the operation lever 45 exposed above the step, so that the operation of the pedals 23 and 24 and the rotation speed of the engine 5 can be easily switched. it can.

  Moreover, the tractor 1 of this embodiment is configured as follows. That is, the neutral return arm 53 has a plate support portion 53d that rotatably supports the connecting plate 46. The neutral return arm 53 has a long hole 53c. The accelerator operation arm 65 has a long hole 65c. The connecting plate 46 has a convex portion 46b that can be inserted into the long holes 53c and 65c. And the state where the convex part 46b was inserted in both the two long holes 53c and 65c by the rotation of the connection plate 46, and the state where the convex part 46b was not inserted in any of the long holes 53c and 65c, Configured to be feasible. The operation lever 45 is connected to the connection plate 46.

  Thereby, the connection plate 46 can be rotated by operating the end portion of the operation lever 45 exposed above the step plate 12. As described above, the operator can switch the presence / absence of the linkage between the pedals 23 and 24 and the rotational speed of the engine 5 from above the steps with a simple configuration.

  Next, a second embodiment of the present invention will be described. In the present embodiment, the presence / absence of interlocking between the rotational speed of the engine 5 and the operation of the pedals 23 and 24 is further simplified than the above embodiment.

  A perspective view of the forward / reverse pedal unit 10 according to the second embodiment is shown in FIG. 22, and a schematic front sectional view is shown in FIG. In the following description, the same or similar components as those of the above embodiment are denoted by the same reference numerals as those of the above embodiment, and the description thereof is omitted. As shown in FIG. 22 and the like, the accelerator interlocking switching mechanism 101 in the present embodiment includes a neutral return arm 53, an accelerator operation arm 65, and a connecting pin (fixing member) 56.

  In this embodiment, a connecting pin 56 is used as a fixing member instead of the connecting plate 46 of the first embodiment. As shown in FIGS. 22 and 23, the connecting pin 56 is formed as a round bar-like member bent into a U-shape (folded shape).

  On the other hand, as shown in FIG. 23, the neutral return arm 53 is formed with an insertion hole (first insertion hole) 53x into which the end of the round bar-like connecting pin 56 can be inserted. Similarly, the accelerator operating arm 65 is formed with an insertion hole (second insertion hole) 65x into which an end of the round bar-like connecting pin 56 can be inserted.

  One end side of the U-shape of the connecting pin 56 is supported so as to be rotatable and axially movable with respect to the neutral return arm 53. The other end side of the U-shape of the connecting pin 56 can be inserted into the insertion holes 53x and 65x. And the neutral return arm 53 and the accelerator operation arm 65 are mutually fixed by inserting the edge part of the connection pin 56 in insertion hole 53x, 65x. Thereby, similarly to 1st Embodiment, operation of the pedals 23 and 24 and the rotational speed of the engine 5 can be made to interlock | cooperate.

  The connecting pin 56 is supported by the neutral return arm 53 so as to be movable in the direction in which the insertion hole 53x is formed. Therefore, by sliding the connecting pin 56 from the state of FIG. 23, the connecting pin 56 can be removed from the insertion holes 53x and 65x, and the neutral return arm 53 and the accelerator operating arm 65 can be released from being fixed. An urging spring 56 a that urges the connection pin 56 in a direction in which the connection pin 56 is inserted into the insertion holes 53 x and 65 x is disposed between the connection pin 56 and the neutral return arm 53. Thereby, it can prevent that the connecting pin 56 remove | deviates from insertion hole 53x, 65x by the vibration at the time of driving | running | working, etc.

  To release the fixation between the neutral return arm 53 and the accelerator operation arm 65, the operator performs the following operation.

  That is, since the connecting pin 56 of this embodiment cannot be operated from above the step plate 12 as in the first embodiment, the operator inserts his hand under the step plate 12 to Perform the operation. Specifically, the end of the connecting pin 56 is removed from the insertion holes 53x and 65x, and the connecting pin 56 is slid with respect to the neutral return arm 53 (from the state of FIG. 23 to the left). Thereby, fixation of the neutral return arm 53 and the accelerator operation arm 65 can be cancelled | released.

  Then, with the connecting pin 56 completely removed from the insertion hole 53x, the connecting pin 56 is rotated relative to the neutral return arm 53 to obtain the state shown in FIG. In this way, as shown in FIG. 24, the position of the end portion of the connecting pin 56 does not coincide with the insertion hole 53x. . Thereby, the state in which the neutral return arm 53 and the accelerator operation arm 65 are released from the fixed state can be maintained.

  As described above, the tractor of the present embodiment is configured as follows. That is, the neutral return arm 53 has the insertion hole 53x. The accelerator operation arm 65 has an insertion hole 65x. The neutral return arm 53 and the accelerator operation arm 65 are fixed to each other by inserting the connecting pin 56 into both the two insertion holes 53x and 65x. On the other hand, by removing the connecting pin 56 from the two insertion holes 53x and 65x, the neutral return arm 53 and the accelerator operation arm 65 are released from being fixed.

  Thereby, the switching of the interlocking state between the pedals 23 and 24 and the rotational speed of the engine 5 can be realized with a simple configuration using insertion / removal of the connecting pin 56 into the insertion holes 53x and 65x.

  Although the preferred embodiment of the present invention has been described above, the above configuration can be changed as follows, for example.

  Although the first interlocking member and the second interlocking member are wires, the present invention is not limited to this, and may be configured by, for example, an arm-shaped member. Moreover, you may comprise as a link mechanism which consists of several components.

  The continuously variable transmission is not limited to an inline type HST, but may be a normal HST, for example.

  In the above embodiment, the neutral return mechanism 33 is provided on the forward pedal arm 21 side. However, the neutral return mechanism 33 may be provided on the reverse pedal arm 22 side instead of this configuration.

  In the above embodiment, the potentiometer 34 detects the rotation amount of the forward pedal arm 21 (more precisely, the rotation amount of the rotation center portion 21a of the forward pedal arm 21). However, the rotation amount of the reverse pedal arm 22 is detected by the potentiometer. You may comprise so that it may detect by.

  Further, the detection mechanism for electrically detecting the operation amounts of the forward pedal 23 and the reverse pedal 24 is not limited to a potentiometer, and may be a rotary encoder, for example.

1 Tractor (work vehicle)
5 Engine 5a Governor device 5b Control lever 8 Driver's seat 12 Step plate (step member)
23 Forward pedal 24 Reverse pedal 29 Continuously variable transmission 30 Hand accelerator lever 31 Pedal bracket (support member)
34 Potentiometer (detector)
46 Connecting plate (fixing member)
46a Rotation center part 46b Convex part 53 Neutral return arm (first arm member)
53c Long hole (first insertion hole)
53d Plate support part (fixing member support part)
65 Accelerator operation arm (second arm member)
65c long hole (second insertion hole)
66 First wire (first interlocking member)
67 Second wire (second interlocking member)
80 Actuator

Claims (6)

An engine located at the front of the car body,
A driver's seat disposed behind the engine;
A work vehicle comprising:
A hand accelerator lever disposed between the engine and the driver seat in plan view;
An operating part that is arranged in the vicinity of the hand accelerator lever and is operable in conjunction with the operation of the hand accelerator lever;
A pedal disposed between the engine and the driver seat in plan view;
A support member for supporting the arm portion of the pedal;
An accelerator interlocking switching mechanism supported by the support member;
With
The operating portion and the accelerator interlocking switching mechanism are connected by a first interlocking member,
The operating part and the governor device of the engine are connected by a second interlocking member,
The work vehicle characterized in that the accelerator interlocking switching mechanism can switch between a state in which the pedal and the first interlocking member are interlocked and a state in which the interlock is released. The work vehicle according to claim 1,
A continuously variable transmission disposed at the rear of the vehicle body for shifting the output of the engine;
A detection unit that electrically detects an operation amount of the pedal;
With
A work vehicle that changes a gear ratio of the continuously variable transmission based on a detection result of the detection unit. The work vehicle according to claim 1 or 2,
The accelerator interlock switching mechanism is
A first arm member that operates in conjunction with the pedal;
A second arm member coupled to the first interlocking member and movable relative to the first arm member;
A fixing member capable of switching between a state in which the first arm member and the second arm member are fixed to each other and a state in which the fixing is released;
A work vehicle comprising: The work vehicle according to claim 3,
The support member is attached to the step member from the lower surface side of the step member of the driver seat,
The accelerator interlocking switching mechanism includes an operation tool exposed above the step member,
A work vehicle characterized in that the fixing of the first arm member and the second arm member by the fixing member and the release of the fixing can be switched by the operation tool. The work vehicle according to claim 4,
Either one of the first arm member and the second arm member has a fixing member support portion that rotatably supports the fixing member,
The first arm member has a first insertion hole;
The second arm member has a second insertion hole;
The fixing member has a protrusion that can be inserted into the first insertion hole and the second insertion hole,
At least one of the first insertion hole and the second insertion hole is in a state where the convex portion is inserted into both the first insertion hole and the second insertion hole due to the rotation of the fixing member. The state in which the convex portion is not inserted is configured to be at least realizable,
A work vehicle, wherein the operation tool is connected to the fixing member. The work vehicle according to claim 3,
The first arm member has a first insertion hole;
The second arm member has a second insertion hole;
The fixing member is configured as a pin-shaped member,
By inserting the fixing member into both the first insertion hole and the second insertion hole, the first arm member and the second arm member are fixed to each other,
The fixing of the first arm member and the second arm member is released by removing the fixing member from at least one of the first insertion hole and the second insertion hole. Work vehicle.

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