JP2008254536A - Working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable an operator's hand to easily reach various operation means while certainly maintaining functions inherently possessed by an arm rest (function for placing and resting an arm) in a working vehicle constituted such that motive power from an engine mounted on a traveling machine body is changed in speed by a hydraulic type continuously variable transmission and is transmitted to traveling parts and working parts. <P>SOLUTION: The arm rest 271 for placing an arm and hand of the operator is arranged at at least either one of left and right sides of an operation seat 8 in the traveling machine body. A main shift lever 290 and a working part position lever 300 are arranged on an upper surface of the arm rest 271. The arm rest 271 is constituted such that it is turnable in a vertical direction making a pivot-support shaft 275 at a rear end side as a fulcrum and the turning attitude can be adjusted to a plurality of stages. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a work vehicle such as a tractor for agricultural work or a wheel loader for civil engineering work.

  Conventionally, in a tractor as a work vehicle, a plurality of work systems for setting and adjusting a work state of a traveling machine body and a rotary tiller on an upper surface of an armrest disposed on at least one of left and right sides of a control seat There is one in which operation means are arranged together.

  An example of such a tractor is disclosed in Patent Document 1. In the tractor of Patent Document 1, a working part position lever, a tilt manual switch, a tilt setting device, a tilling depth setting device, an automatic horizontal switch, and an automatic function are provided on the armrest located on the right side in the traveling direction of the control seat. A working depth switch is arranged.

The working part position lever is for manually changing and adjusting the height position of the rotary tiller, and the tilt manual switch is for manually changing and adjusting the left and right tilt angle of the rotary tiller. The inclination setter pre-sets the target left / right inclination angle of the rotary tiller relative to the traveling machine body, and the tilling depth setter pre-sets the target tilling depth of the rotary tiller. Furthermore, the automatic horizontal switch operates on / off of the automatic horizontal control that maintains the rotary tiller in a horizontal horizontal posture, and the automatic tiller switch switches the tiller depth that maintains the rotary tiller at a predetermined tiller depth position. It operates on / off of automatic control.
Japanese Utility Model Publication No. 62-122508 JP-A-8-242611

  However, in the configuration of Patent Document 1, since many work system operation means (switches) are present on the upper surface of the armrest, if the armrest is used as an armrest as usual, the arm placed on the armrest There has been a problem that an elbow or the like may accidentally contact each operation system operating means, resulting in malfunction.

  In this regard, the applicant of the present invention, in Patent Document 2, arranges various switches of the work system on the downwardly concave step formed on the upper surface rear portion of the armrest, and arranges the work equipment lifting lever on the front surface of the armrest. Proposed. If such a configuration is adopted, if the arm or elbow is placed on the raised portion of the armrest that is located in front of the upper surface, there is little risk of the arm or elbow inadvertently coming into contact with various working switches in the stepped portion. At the same time, the work implement lifting lever can be operated in an easy posture with the arm placed on the raised portion.

  The invention of the present application further develops the concept of Patent Document 2, which is the prior application of the present invention, so that the operator's hand can easily reach various operation means, and the function that the armrest originally has (resting on the arm) It is a technical issue to reliably maintain (function).

  In order to achieve this technical problem, the invention of claim 1 is configured so that power from an engine mounted on a traveling machine body is shifted by a hydraulic continuously variable transmission and transmitted to a traveling unit and a working unit. An armrest for placing an operator's arm or hand is disposed on at least one of the left and right sides of the control seat in the traveling machine body, and traveling system operation means is provided on the upper surface of the armrest. And the working system operating means are arranged, the armrest is configured to be able to rotate in the vertical direction with the rear end side as a fulcrum, and the rotation posture is configured to be adjustable in a plurality of steps or continuously. Is.

  According to a second aspect of the present invention, the work vehicle according to the first aspect further includes a posture detection switch for detecting whether or not the armrest is in the highest rotation posture. When it is in a dynamic posture, it is configured to restrict the starting of the engine.

  According to a third aspect of the present invention, in the work vehicle according to the first aspect, the armrest is provided with a posture detection switch for detecting whether or not the armrest is in a highest rotation posture, and the armrest is driven while the engine is being driven. Is in the neutral position, the hydraulic continuously variable transmission is maintained in a neutral state, the engine is in an idling state, power transmission to the working unit is interrupted, and the traveling unit is in a braking state. The parking brake means for maintaining the vehicle is configured to be in the on state.

  According to the first aspect of the present invention, the armrest for placing the arm or hand of the operator is disposed on at least one of the left and right sides of the control seat in the traveling body, and the traveling system operation means and the working system are disposed on the upper surface of the armrest. The operating means is arranged, and the armrest can be rotated in the vertical direction with the rear end side as a fulcrum, and the rotation posture is configured to be adjustable in a plurality of steps or steplessly. The operating positions of the system operating means and the working system operating means are close to the operator, and the operability of the traveling system operating means and the working system operating means is good. Thus, the rotational posture of the armrest can be adjusted stepwise or steplessly.

  For this reason, while being excellent in the operability (handleability) of the travel system operation means and the work system operation means, it is possible to accurately support the operator's arm or set it so as not to hit the knee. Play.

  According to a second aspect of the present invention, there is provided an attitude detection switch for detecting whether or not the armrest is in the highest rotation attitude, and when the armrest is in the highest rotation attitude when the power is turned on, Since the start is restricted, the engine will not start if the right armrest is in the uppermost turning posture when the power is turned on, and the running unit and the working unit are not driven. For this reason, when the operator gets on and off, even if the traveling system operating means or the working system operating means on the armrest that is in the uppermost rotation position is inadvertently contacted, the traveling section or the working section may suddenly move. There is no effect, and the safety of the work vehicle is improved.

  According to a third aspect of the present invention, there is provided an attitude detection switch for detecting whether or not the armrest is in the uppermost rotation attitude, and when the armrest is in the uppermost rotation attitude during the driving of the engine, The hydraulic continuously variable transmission is maintained in a neutral state, the engine is in an idling state, power transmission to the working unit is interrupted, and parking brake means for maintaining the traveling unit in a braking state is entered. It is configured to be in a state.

  By adopting such a configuration, even when the engine is being driven, it is possible to stop the driving of the traveling unit and the working unit all at once by simply turning the armrest to the highest rotation position. As a result, it is possible to exert a high effect on improving the safety of work vehicles.

  Hereinafter, an embodiment in which the present invention is applied to a tractor as a work vehicle will be described based on the drawings (FIGS. 1 to 13). 1 is a left side view of the tractor, FIG. 2 is a plan view of the tractor, FIG. 3 is a skeleton diagram of a power transmission system, FIG. 4 is a hydraulic circuit diagram of a hydraulic continuously variable transmission, FIG. 5 is a hydraulic circuit diagram of the tractor, 6 is a functional block diagram of the controller, FIG. 7 is a plan view of the cabin, FIG. 8 is a left side sectional view of the cabin, FIG. 9 is a left side view of the armrest, FIG. 10 is an enlarged left side view of the extension portion, and FIG. Fig. 12 is a plan view of the armrest, Fig. 12 is a perspective view of the armrest as viewed obliquely from above, and Fig. 13 is an electric circuit diagram of the safety mechanism. In FIG. 2, the cabin is not shown for convenience.

(1). First, an outline of a tractor will be described with reference to FIGS. 1 and 2.

  The traveling machine body 2 of the tractor 1 in the embodiment is supported by a pair of left and right rear wheels 4 as well as a pair of left and right front wheels 3 as a traveling unit. The tractor 1 is configured to travel forward and backward by driving the rear wheels 4 and the front wheels 3 with a diesel engine 5 mounted on the front portion of the traveling machine body 2. The engine 5 is covered with a bonnet 6. A cabin 7 is installed on the upper surface of the traveling machine body 2. Inside the cabin 7, a steering seat 8 and a steering handle (round handle) that moves the steering direction of the front wheel 3 to the left and right by steering. 9 are arranged. A fuel tank 11 that supplies fuel to the engine 5 is provided below the bottom of the cabin 7.

  The steering handle 9 in the cabin 7 is provided on a steering column 245 erected in front of the steering seat 8. On the right side of the steering column 245, a throttle lever 250 for setting and maintaining the output rotational speed of the engine 5 and a pair of left and right brake pedals 251 for braking the traveling machine body 2 are disposed. On the left side of the steering column 245, a forward / reverse switching lever 252 for switching the traveling direction of the traveling machine body 2 between forward and reverse, and a clutch pedal 253 for operating the main clutch 140 to be described later are disposed. ing. A parking brake lever 254 for holding the left and right brake pedals 251 in the depressed position is disposed on the rear side of the steering column 245.

  On the right side of the steering column 245 of the floor plate 248 in the cabin 7 is an accelerator pedal for increasing and decelerating the engine speed in a range beyond this, with the engine speed set by the throttle lever 250 being the minimum engine speed. 255 is arranged. Below the control seat 8 are a PTO speed change lever 256 for switching the drive speed of the PTO shaft 23, which will be described later, and a diff lock pedal 257 for executing an operation of rotating the left and right rear wheels 4 at a constant speed. Is arranged.

  On the other hand, the traveling machine body 2 includes an engine frame 14 having a front bumper 12 and a front axle case 13 and left and right machine body frames 16 that are detachably fixed to the rear portion of the engine frame 14 with bolts. A mission case 17 is mounted on the rear part of the machine body frame 16 to transmit the rotational power from the engine 5 to the front and rear four wheels 3, 3, 4, 4 as appropriate. The rear wheel 4 is attached to the mission case 17 via a rear axle case 18 mounted so as to protrude outward from the outer surface of the mission case 17. Upper portions of the left and right rear wheels 4 are covered with a fender 19 fixed to the body frame 16.

  On the rear upper surface of the mission case 17, a hydraulic lifting mechanism 20 for lifting and lowering the rotary tiller 15 as a working unit is detachably attached. The rotary cultivator 15 is connected to the rear portion of the mission case 17 via a three-point link mechanism including a pair of left and right lower links 21 and a top link 22. On the rear side surface of the mission case 17, a PTO shaft 23 for transmitting a PTO driving force to the rotary cultivator 15 protrudes backward.

(2). Next, the structure of the hydraulic circuit 120 of the tractor 1 will be described with reference to FIG.

  The hydraulic circuit 120 of the tractor 1 includes a working hydraulic pump 94 and a traveling hydraulic pump 95 that are operated by the rotational force of the engine 5. The working hydraulic pump 94 and the traveling hydraulic pump 95 are provided on the front side of the front side wall member 32 of the transmission case 17. The working hydraulic pump 94 is connected to a control electromagnetic valve 121 for supplying hydraulic oil to the single-acting hydraulic cylinder 125 of the hydraulic lifting mechanism 20.

  The traveling hydraulic pump 95 is for supplying hydraulic oil to the hydraulic continuously variable transmission 29 and the power steering hydraulic cylinder 93 in the mission case 17. In this case, the mission case 17 is also used as an oil tank, and hydraulic oil inside the mission case 17 is supplied to the hydraulic pumps 94 and 95.

  The traveling hydraulic pump 95 is connected to a hydraulic cylinder 93 for power steering by the steering handle 9 via a control valve 122 for power steering, while a brake cylinder 68a for a pair of left and right brake operating mechanisms 65a, 65b, It is also connected to autobrake solenoid valves 67a and 67b for operating 68b.

  Furthermore, the traveling hydraulic pump 95 includes a PTO clutch hydraulic solenoid valve 104 for operating the PTO clutch 100, a proportional control valve 123 for the hydraulic continuously variable transmission 29 in the transmission case 17, and a switching valve 124 operated thereby. A high-speed clutch electromagnetic valve 136 of the auxiliary transmission hydraulic cylinder 55, a forward clutch electromagnetic valve 46 and a reverse clutch electromagnetic valve 48 for operating the hydraulic clutches 40 and 42 for forward / reverse switching of the traveling machine body 2, and the front wheels 4 drive hydraulic solenoid valve 80 for 4WD hydraulic clutch 74 for driving 3 and rear wheel 4 simultaneously, and double speed hydraulic solenoid valve 82 for double speed hydraulic clutch 76 for switching front wheel 3 to double speed drive Has been.

  The forward clutch solenoid valve 46, the reverse clutch solenoid valve 48, the four-wheel drive hydraulic solenoid valve 80, the double speed hydraulic solenoid valve 82, and the PTO clutch hydraulic solenoid valve 104 are appropriately connected to the respective solenoid valves 46, 48, 80, 82, 104. When controlled by the means, the hydraulic clutches 40, 42, 74, 76, 100 are configured to be switched and driven by the operation of the corresponding clutch cylinders 47, 49, 81, 83, 105. The hydraulic circuit 120 also includes a relief valve, a flow rate adjustment valve, a check valve, an oil cooler, an oil filter, and the like.

(3). Next, the power transmission system of the tractor 1 and the hydraulic circuit structure in the transmission case 17 will be described with reference to FIGS. 3 and 4.

  The mission case 17 has a hollow box shape. A front side wall member 32 is fixed to the front surface of the mission case 17 and a rear side wall member 33 is detachably fixed to the rear surface with bolts. The interior of the mission case 17 is divided forward and backward by a partition wall 31, and is divided into a front chamber 34 and a rear chamber 35 by the presence of the partition wall 31. Although not shown in detail, the front chamber 34 and the rear chamber 35 communicate with each other so that internal hydraulic oil (lubricating oil) can move between them.

  As shown in FIG. 3, the front side wall member 32 includes a front wheel drive case 69. In the front chamber 34, a traveling auxiliary transmission gear mechanism 30 and a PTO transmission gear mechanism 96 (details will be described later) are arranged. A hydraulic continuously variable transmission 29 and a differential gear mechanism 58 (details will be described later) are disposed in the rear chamber 35.

  A flywheel 25 is attached to an engine output shaft 24 projecting rearward on the rear side of the engine 5 so as to be directly connected. The flywheel 25 and the main shaft 26 extending rearward therefrom are connected via a main clutch 140 for power transmission. The main drive shaft 26 and the main transmission input shaft 27 projecting forward from the transmission case 17 are connected via an extendable power transmission shaft 28 having universal shaft joints at both ends.

  The rotational power of the engine 5 is transmitted from the engine output shaft 24 to the main transmission input shaft 27 of the transmission case via the main driving shaft 26 and the power transmission shaft 28, and then the hydraulic continuously variable transmission 29 and the traveling auxiliary transmission gear. The speed is appropriately changed with the mechanism 30. This speed change power is transmitted to the left and right rear wheels 4 via the differential gear mechanism 58. The above-described speed change power is also transmitted to the left and right front wheels 3 via the front wheel drive case 69 and the differential gear mechanism 86 of the front axle case 13.

(3-1). Detailed Configuration of Hydraulic Continuously Variable Transmission An inline hydraulic continuously variable transmission 29 in the rear chamber 35 is formed by concentrically arranging a main transmission output shaft 36 on a main transmission input shaft 27. , A variable displacement speed change hydraulic pump section 150 and a constant capacity speed change hydraulic motor section 151 that is operated by high-pressure hydraulic oil discharged from the hydraulic pump section 150. A rear end side of the main transmission input shaft 27 opposite to the input side (front end side) is rotatably supported by the rear side wall member 33 via a ball bearing.

  The cylindrical main transmission output shaft 36 is fitted on the front side of the hydraulic continuously variable transmission 29, that is, the input side of the main transmission input shaft 27. A middle portion of the main transmission output shaft 36 penetrates the partition wall 31 and is rotatably supported by the partition wall 31 by two sets of ball bearings. The main transmission output shaft 36 has a front end projecting into the front chamber 34 and a rear end projecting into the rear chamber 35. A main transmission output gear 37 for taking out transmission power from the hydraulic continuously variable transmission 29 is fixed to the outer periphery of the front end of the main transmission output shaft 36. The input side (front end side) of the main transmission input shaft 27 is rotatably supported by the shaft hole of the main transmission output shaft 36 via a roller bearing in a state of protruding forward from the front end of the main transmission output shaft 36. .

  A cylinder block 155 for operating the hydraulic pump unit 150 and the hydraulic motor unit 151 is fitted on a portion of the main transmission input shaft 27 between the partition wall 31 and the rear side wall member 33. In the embodiment, the hydraulic motor unit 151 is disposed near the input side of the main transmission input shaft 27 across the cylinder block 155, while the hydraulic pump unit 150 is disposed far from the input side of the main transmission input shaft 27. Has been placed.

  The hydraulic pump unit 150 can change the inclination angle of the main transmission input shaft 27 with respect to the first holder (not shown) fixed to the inner side surface of the transmission case 17 so as to face the rear side surface of the cylinder block 155. A pump swash plate 159 disposed in the first holder, a pump plunger 156 connected to a shoe (not shown) slidably provided on the pump swash plate 159 via a spherical joint, and a pump plunger And a first plunger hole 157 for detachably attaching the cylinder 156 to the cylinder block 155. One end of the pump plunger 156 protrudes from the side surface of the cylinder block 155 toward the pump swash plate 159 (right side in FIG. 4).

  On the other hand, the hydraulic motor unit 151 is arranged to face the side surface of the cylinder block 155 and is fixed to the second holder so as to keep the inclination angle with respect to the second holder (not shown) and the axis of the main transmission input shaft 27 constant. Motor swash plate 168, a motor plunger 165 connected to a shoe (not shown) slidably mounted on the motor swash plate 168 via a spherical universal joint, and the motor plunger 165 is moved in and out of the cylinder block 155. And a second plunger hole 166 for freely mounting. One end of the motor plunger 165 protrudes from the side surface of the cylinder block 155 toward the motor swash plate 168 (left side in FIG. 4).

  There are the same number of pump plungers 156 and motor plungers 165, and they are alternately arranged on the same circumference of the rotation center of the cylinder block 155. The cylinder block 155 is provided with the same number of first spool valves 176 as the pump plungers 156 and the same number of second spool valves 180 as the motor plungers 165. In addition, a first radial bearing 177 is disposed in the first holder so as to be inclined at a constant inclination angle with respect to the axis of the main transmission input shaft 27. A second radial bearing 181 is disposed in the second holder so as to be inclined at a constant inclination angle with respect to the axis of the main transmission input shaft 27.

  Further, a ring-shaped first oil chamber 170 and a second oil chamber 171 are respectively formed in the shaft holes into which the main transmission input shaft 27 is inserted in the cylinder block 155. The cylinder block 155 is formed with a first valve hole 172 and a second valve hole 173 that are arranged at substantially equal intervals on the same circumference of the rotation center. The first valve hole 172 and the second valve hole 173 communicate with the first oil chamber 170 and the second oil chamber 171, respectively. The first plunger hole 157 communicates with the first valve hole 172 via the first oil passage 174, and the second plunger hole 166 communicates with the second valve hole 173 via the second oil passage 175.

  The first spool valves 176 inserted into the first valve holes 172 are arranged at substantially equal intervals on the same circumference of the rotation center of the cylinder block 155. The front end of the first spool valve 176 protrudes from the first valve hole 172 toward the first holder by the elastic pressure of the back pressure spring force, and is in contact with the outer ring side surface of the first radial bearing 177. When the first spool valve 176 reciprocates once by one rotation of the cylinder block 155, the first plunger hole 157 is connected to the first oil chamber 170 or the second oil via the first valve hole 172 and the first oil passage 174. It is set to communicate with the oil chamber 171 alternately.

  The second spool valves 180 inserted into the second valve holes 173 are also arranged at substantially equal intervals on the same circumference of the rotation center of the cylinder block 155. The tip of the second spool valve 180 protrudes from the second valve hole 173 toward the second holder by the elastic pressure of the back pressure spring force, and is in contact with the outer ring side surface of the second radial bearing 181. When the second spool valve 180 reciprocates once in one rotation of the cylinder block 155, the second plunger hole 166 is connected to the first oil chamber 170 or the second oil via the second valve hole 173 and the second oil passage 175. It is set to communicate with the oil chamber 171 alternately.

  A hydraulic oil supply oil passage 183 extending in the axial direction is formed at the center of the main transmission input shaft 27. The hydraulic oil supply oil passage 183 opens rearward on the rear end face of the main transmission input shaft 27 and communicates with the discharge port of the traveling hydraulic pump 95.

  The hydraulic oil supply oil passage 183 is provided with a first charge valve 184 for the first oil chamber 170 and a second charge valve 185 for the second oil chamber 171, and these charge valves 184 and 185 are provided via these charge valves 184 and 185. The hydraulic oil from the hydraulic oil supply oil passage 183 is supplied to the hydraulic closed circuit 187 formed between the first and second plunger holes 157 and 166 and the first and second oil chambers 170 and 171. It is configured. Note that hydraulic oil from the hydraulic oil supply oil passage 183 is also supplied as lubricating oil to the rotating portions of the hydraulic pump unit 150 and the hydraulic motor unit 151 via check valves.

  The pump swash plate 159 is disposed on the outer periphery of the small diameter portion of the first holder via the tilt angle adjustment fulcrum 189. The tilt angle of the pump swash plate 159 is configured to be adjustable with respect to the axis of the main transmission input shaft 27. The pump swash plate 159 is associated with a main transmission hydraulic cylinder 190 that changes and adjusts the inclination angle of the pump swash plate 159 with respect to the axis of the main transmission input shaft 27 (see FIGS. 4 and 5). By changing the inclination angle of the pump swash plate 159 by driving the main transmission hydraulic cylinder 190, the main transmission operation of the hydraulic continuously variable transmission 29 is executed.

(3-2). Next, the speed change operation of the hydraulic stepless transmission 29 by the main speed change hydraulic cylinder 190 will be described in detail. When the switching valve 124 is operated by hydraulic fluid from the proportional control valve 123 that operates in proportion to the amount of tilting operation of the main transmission lever 290 (details will be described later), the main transmission hydraulic cylinder 190 is driven, and the main transmission hydraulic cylinder. The tilt angle of the pump swash plate 159 with respect to the axis of the main transmission input shaft 27 is changed in conjunction with the upward and downward movement of the piston 190.

  When the inclination angle of the pump swash plate 159 is substantially zero, the cylinder block 155 of the main transmission input shaft 27 and the motor swash plate 168 of the hydraulic motor unit 151 rotate in the same direction at substantially the same number of rotations, and the main transmission input The main transmission output shaft 36 also rotates at substantially the same rotational speed as the shaft 27. As a result, the rotational speed of the main transmission input shaft 27 is transmitted to the main transmission output gear 37 as it is (without changing).

  When the pump swash plate 159 is tilted in one direction (positive tilt angle) with respect to the axis of the main transmission input shaft 27, the motor swash plate 168 rotates in the same direction as the cylinder block 155, and the hydraulic motor unit 151 is increased in speed, and the main transmission output shaft 36 rotates at a higher rotational speed than the main transmission input shaft 27. As a result, the rotational speed of the main transmission input shaft 27 is transmitted to the main transmission output gear 37 in an increased state. In other words, the rotational speed of the hydraulic motor unit 151 is added to the rotational speed of the main transmission input shaft 27 and transmitted to the main transmission output gear 37.

  Therefore, in the range of the rotational speed higher than the rotational speed of the main transmission input shaft 27, the transmission power (traveling speed) from the main transmission output gear 37 is proportional to the inclination angle (positive inclination angle) of the pump swash plate 159. Is changed. When the pump swash plate 159 has the maximum inclination angle (positive inclination angle), the traveling machine body 2 has the maximum traveling speed.

  When the pump swash plate 159 is tilted in the other direction (negative tilt angle) with respect to the axis of the main transmission input shaft 27, the motor swash plate 168 rotates in the direction opposite to the cylinder block 155, and the hydraulic motor The part 151 is decelerated (reversely rotated), and the main transmission output shaft 36 rotates at a lower rotational speed than the main transmission input shaft 27. As a result, the rotational speed of the main transmission input shaft 27 is transmitted to the main transmission output gear 37 in a reduced state. That is, the rotational speed of the hydraulic motor 151 is subtracted from the rotational speed of the main transmission input shaft 27 and transmitted to the main transmission output gear 37.

  Therefore, in the range of the rotational speed lower than the rotational speed of the main transmission input shaft 27, the transmission power (traveling speed) from the main transmission output gear 37 is proportional to the inclination angle (negative inclination angle) of the pump swash plate 159. Is changed. When the pump swash plate 159 has the maximum inclination angle (negative inclination angle), the traveling machine body 2 has the minimum traveling speed.

(3-3). Configuration for switching between forward and reverse travel of the traveling machine body As shown in FIG. 3, in the front chamber 34 of the mission case 17, a forward gear 41 and a reverse gear 43 for switching the forward and backward travel of the traveling machine body 2 are arranged. Yes. In the embodiment, a travel counter shaft 38 and a reverse rotation shaft 39 are provided in the front chamber 34, and the forward gear 41 and the reverse gear 43 are fitted on the travel counter shaft 38.

  The forward gear 41 is configured to be connected to the travel counter shaft 38 so as to rotate integrally with the wet multi-plate forward hydraulic clutch 40, and meshes with the main transmission output gear 37. The main transmission output gear 37 is also meshed with a reverse gear 44 fixed to the reverse shaft 39. The reverse gear 43 is configured to be connected to the travel counter shaft 38 so as to rotate integrally with the wet multi-plate type reverse hydraulic clutch 42, and meshes with the reverse output gear 45 fixed to the reverse shaft 39. Yes.

  In this case, the forward clutch solenoid valve 46 is driven by the forward side tilting operation of the forward / reverse switching lever 252 (see FIGS. 1 and 2) to operate the forward clutch cylinder 47, and the forward hydraulic clutch 40 is motively connected. Put it in a state. As a result, the main transmission output gear 37 and the travel counter shaft 38 are coupled via the forward gear 41 so that power can be transmitted (see FIG. 3).

  Further, the reverse clutch solenoid valve 48 is driven by the reverse operation of the forward / reverse switching lever 252 to actuate the reverse clutch cylinder 49 to bring the reverse hydraulic clutch 42 into a power connection state. As a result, the main transmission output gear 37 and the travel counter shaft 38 are coupled to each other so as to be able to transmit power via the reverse gear 44 and the reverse output gear 45 on the reverse shaft 39 and the reverse gear 43 (see FIG. 3).

  In the neutral state in which the forward / reverse switching lever 252 is not tilted and operated, both the forward and reverse hydraulic clutches 40 and 42 are in the power cut-off state, and the main transmission output gear 37 and the front and rear wheels 3 and 4 are cut off. The rotational power toward is substantially zero (the same state as when the main clutch 140 is disengaged).

(3-4). Configuration for Switching Between Low Speed and High Speed Next, a configuration for switching between low speed and high speed via the traveling auxiliary transmission gear mechanism 30 will be described.

  In the front chamber 34 of the mission case 17, in addition to the traveling counter shaft 38 and the reverse rotation shaft 39, a traveling auxiliary transmission gear mechanism 30 and an auxiliary transmission shaft 50 are also arranged. The travel counter shaft 38 is provided with a counter low-speed gear 51 and a counter high-speed gear 53 for sub-transmission, while the sub-transmission shaft 50 has a low-speed gear 52 that meshes with the counter low-speed gear 51 and a counter high-speed gear 53. A meshing high speed gear 54 is provided. The auxiliary transmission shaft 50 is also provided with a low-speed clutch 56 and a high-speed clutch 57 that can be connected / disconnected by the auxiliary transmission hydraulic cylinder 55.

  In this case, the auxiliary transmission hydraulic cylinder 55 is driven in response to a pressing operation of an auxiliary transmission changeover switch 231 to be described later or detection of the rotational speed of the engine 5, and the low speed clutch 56 or the high speed clutch 57 is brought into a power connection state. As a result, the low speed gear 52 or the high speed gear 54 is connected to the auxiliary transmission shaft 50 so as to rotate integrally, and rotational power is output from the auxiliary transmission shaft 50 toward the front and rear wheels 3 and 4.

  The auxiliary transmission hydraulic cylinder 55 has a double-action structure having a piston rod 131 on one side of the piston 130. In the auxiliary transmission hydraulic cylinder 55, a first cylinder chamber 132 having a built-in piston rod 131 and the other second cylinder chamber 133 are formed. An auxiliary transmission shifter 135 is connected to the tip of the piston rod 131 via a shift arm 134. By setting the low speed clutch 56 or the high speed clutch 57 to the power connected state by the sub transmission shifter 135, the sub transmission shaft 50 is configured to be driven at a low speed or a high speed.

  The first cylinder chamber 132 communicates directly with the discharge side of the traveling hydraulic pump 95. The second cylinder chamber 133 communicates with the discharge side of the traveling hydraulic pump 95 via a two-position, three-port high-speed clutch solenoid valve 136. The high speed clutch solenoid valve 136 includes a speed change solenoid 137 (see FIG. 5).

  In the embodiment, when the high-speed clutch solenoid valve 136 is switched by the shift solenoid 137 and the second cylinder chamber 133 communicates with the discharge side of the traveling hydraulic pump 95, the piston rod is caused by the difference in the pressure received on both sides of the piston 130. The piston 130 moves in the direction in which 131 is projected. As a result, the high-speed clutch 57 enters a power connection state, and the auxiliary transmission shaft 50 is driven at a high speed.

  A rear end portion of the auxiliary transmission shaft 50 extends through the partition wall 31 to the inside of the rear chamber 35 of the transmission case 17. A pinion 59 is fixed to the rear end portion of the auxiliary transmission shaft 50. A differential gear mechanism 58 for transmitting rotational power to the left and right rear wheels 4 is disposed in the rear chamber 35.

  The differential gear mechanism 58 includes a ring gear 60 that meshes with the pinion 59 of the auxiliary transmission shaft 50, a differential gear case 61 fixed to the ring gear 60, and a differential output shaft 62 that extends in the left-right direction. The differential output shaft 62 is connected to the rear axle 64 via a final gear 63 and the like, and the rear wheel 4 is attached to the tip of the rear axle 64.

  The differential output shaft 62 is provided with brake operating mechanisms 65a and 65b in association with each other, and the brake operating mechanisms 65a and 65b are operated by depressing the brake pedal 251 (see FIG. 2) on the right side of the steering column 245. Is configured to perform a braking operation. Further, when the steering angle of the steering wheel 9 becomes equal to or greater than a predetermined angle, the brake cylinder 68a (68b) is actuated by driving the autobrake solenoid valve 67a (67b) corresponding to the rear wheel 4 inside the turn, and the inside of the turn is turned on. The brake operation mechanism 65a (65b) for the rear wheel 4 is configured to automatically perform a braking operation. For this reason, small turn turning such as U-turn can be executed.

  The differential gear mechanism 58 disposed in the rear chamber 35 has a differential lock mechanism (not shown) for stopping the differential operation (the left and right differential output shafts 62 are always driven at a constant speed). I have. In this case, the differential gear is fixed to the differential gear case 61 by engaging a lock pin provided in the differential gear case 61 so as to freely enter and exit the differential gear by depressing the differential lock pedal 257 (see FIG. 2). Thus, the differential function is stopped, and the left and right differential output shafts 62 are configured to rotate at a constant speed.

(3-5). Configuration for switching between front and rear wheels 2WD and 4WD Next, a configuration for switching front and rear wheels 3 and 4 between 2WD and 4WD will be described. The front wheel drive case 69 provided on the front side wall member 32 of the mission case 17 includes a front wheel input shaft 72 and a front wheel output shaft 73.

  The front wheel input shaft 72 is connected to the auxiliary transmission shaft 50 through gears 70 and 71 so that power can be transmitted. The front wheel output shaft 73 is connected to the front wheel output shaft 73 so as to rotate integrally with the front wheel output shaft 73 by the action of the four-wheel drive hydraulic clutch 74 and the front wheel output by the action of the double speed hydraulic clutch 76. A double speed gear 77 that can be connected to the shaft 73 so as to rotate integrally is fitted. The four-wheel drive gear 75 meshes with a gear 78 fixed to the front wheel input shaft 72, while the double speed gear 77 also meshes with a gear 79 fixed to the front wheel input shaft 72.

  When a selector switch (not shown) between 2WD and 4WD is operated to the 4WD side, the 4WD clutch cylinder 81 is actuated by driving the 4WD hydraulic solenoid valve 80, and the 4WD hydraulic clutch 74 is powered. Connected. If it does so, the front wheel input shaft 72 and the front wheel output shaft 73 will be connected by the four-wheel drive gear 75 so that power transmission is possible, and the front wheel 3 will drive with the rear wheel 4 (four-wheel drive state).

(3-6). Configuration for Switching Front Wheel Double Speed Drive Next, a configuration for switching the front wheel 3 double speed drive will be described. In this case, when a U-turn (direction change at the headland in the field) operation of the steering handle 9 is detected, the double speed clutch cylinder 83 is actuated by driving the double speed hydraulic solenoid valve 82 and the double speed hydraulic clutch 76 is powered. Compared to the speed when the front wheel 3 is driven by the four-wheel drive gear 75 by connecting the front wheel input shaft 72 and the front wheel output shaft 73 by the double speed gear 77 so that power can be transmitted. Thus, the front wheel 3 is configured to be driven at about twice the high speed.

  A front wheel transmission shaft 84 projecting rearward from the front axle case 13 and a front end portion projecting forward from the front wheel drive case 69 of the front wheel output shaft 73 are connected via a front wheel drive shaft 85. . A differential gear mechanism 86 for transmitting rotational power to the left and right front wheels 3 is disposed inside the front axle case 13.

  The differential gear mechanism 86 includes a ring gear 88 that meshes with a pinion 87 fixed to the front end of the front wheel transmission shaft 84, a differential gear case 89 provided in the ring gear 88, and left and right differential output shafts 90. .

  The differential output shaft 90 is connected to the front axle 92 via a final gear 91 or the like, and the front wheel 3 is attached to the tip of the front axle 92. A hydraulic cylinder 93 for power steering (see FIG. 5) is provided on the outer surface of the front axle case 13 to change the traveling direction of the front wheels 3 to the left and right by the steering operation of the steering handle 9.

(3-7). Configuration for switching the driving speed of the PTO shaft Next, a configuration for switching the driving speed of the PTO shaft 23 (four forward rotations and one reverse rotation) will be described. In the front chamber 34 of the transmission case 17, a PTO transmission gear mechanism 96 for transmitting power from the engine 5 to the PTO shaft 23, and a pump drive for transmitting power from the engine 5 to the hydraulic pumps 94 and 95. A shaft 97 is also arranged.

  The PTO transmission gear mechanism 96 includes a PTO counter shaft 98 and a PTO transmission output shaft 99. The PTO counter shaft 98 is fitted with a PTO input gear 101 that can be connected by a PTO clutch 100 so as to rotate integrally therewith. The PTO input gear 101 is engaged with an input side gear 102 fixed to the main transmission input shaft 27 and an output side gear 103 fixed to the pump drive shaft 97, and the gears 101 to 103 are engaged to drive the pump. A shaft 97 is connected to the main transmission input shaft 27 via a PTO counter shaft 98 so as to be able to transmit power.

  In this case, when a PTO clutch switch 225 (described later) is turned on, the PTO clutch cylinder 105 is actuated by driving the PTO clutch hydraulic solenoid valve 104 (see FIG. 5), and the PTO clutch 100 is brought into a power connection state. As a result, the PTO input gear 101 is connected to the PTO counter shaft 98 so as to rotate integrally, and rotational power is output from the main transmission input shaft 27 toward the PTO counter shaft 98.

  A first speed gear 106, a second speed gear 107, a third speed gear 108, a fourth speed gear 109, and a reverse gear 110 are fitted on the PTO speed change output shaft 99 for output to the PTO shaft 23. The PTO shift output shaft 99 is spline-fitted with the shift shifter 111 so as not to be relatively rotatable and slidable in the axial direction, and the gears 106 to 110 are connected to the PTO shift output shaft 99 by the action of the shift shifter 111. It is comprised so that it may be alternatively connected to. The shift shifter 111 is engaged with a shift arm 112 linked to a PTO shift lever 256 (see FIG. 2).

  When the PTO shift lever 256 is operated to shift, the shift arm 112 slides the shift shifter 111 along the axis of the PTO shift output shaft 99, and the shift shifter 111 selectively selects one of the gears 106 to 110. To the PTO speed change output shaft 99. As a result, the 1st to 4th speed and reverse PTO shift outputs are transmitted from the PTO shift output shaft 99 to the PTO shaft 23 via the gears 113 and 114.

  An electromagnetic pickup type main transmission output shaft rotation sensor 212 (see FIG. 6) is disposed opposite to the rotation detection gear 115 fixed to the reverse rotation shaft 39, and the main transmission output shaft rotation sensor 212 is opposed to the rotation detection gear 115. Thus, the rotation of the main transmission output gear 37 and the output rotation speed of the hydraulic continuously variable transmission 29 are detected. Further, an electromagnetic pickup type vehicle speed sensor 213 (see FIG. 6) for detecting the rotation of the gear 78 is disposed in the vicinity of the gear 78 on the front wheel input shaft 72. The traveling speed (vehicle speed) of the traveling machine body 2 is detected from the rotation of the front wheel input shaft 72 and the auxiliary transmission shaft 50 detected by the vehicle speed sensor 213.

(4). Configuration for Executing Various Tractor Controls Next, a configuration for executing various tractor controls (shift control, automatic horizontal control, tillage depth automatic control, etc.) will be described with reference to FIG.

  A controller 200 as a control means mounted on the tractor 1 includes a CPU for executing various arithmetic processes and controls, a ROM for storing control programs and data, and a RAM for temporarily storing control programs and data. , And an input / output interface and the like, and is connected to the battery 202 via the power application key switch 201. The key switch 201 is a rotary switch that can be rotated by a predetermined key inserted into a key hole, and is attached to a steering column 245 positioned in front of the control seat 8, although not shown in detail.

  An electronic governor controller 204 that controls the rotation of the engine 5 is connected to the controller 200. The electronic governor controller 204 includes a governor 205 that adjusts the fuel of the engine 5, an engine rotation sensor 206 that detects the engine speed, and a throttle potentiometer that detects the operating position of the throttle lever 250 disposed on the right side of the steering column 245. 207 is connected.

  When the throttle lever 250 is manually operated, the electronic governor controller 204 drives the throttle solenoid 208 based on the detection information of the throttle potentiometer 207 so that the set rotational speed of the throttle lever 250 matches the engine rotational speed, and the governor 205 Automatically adjusts the position of a fuel adjustment rack (not shown). For this reason, the engine speed is maintained at a predetermined speed corresponding to the position of the throttle lever 250, regardless of the load variation.

  The controller 200 includes various output-related electromagnetic valves and actuators, that is, a forward clutch electromagnetic valve 46 for the forward hydraulic clutch 40, a reverse clutch electromagnetic valve 48 for the reverse hydraulic clutch 42, and a high speed for the auxiliary transmission hydraulic cylinder 55. A clutch solenoid valve 136, a proportional control valve 123 for operating the main transmission hydraulic cylinder 190 in proportion to a tilting operation amount of a main transmission lever 290, which will be described later, a four-drive hydraulic solenoid valve 80 for the four-drive hydraulic clutch 74, and a double speed Hydraulic oil is supplied to the double speed hydraulic solenoid valve 82 for the hydraulic clutch 76, the left and right autobrake solenoid valves 67a and 67b, the PTO clutch hydraulic solenoid valve 104 for the PTO clutch 100, and the single acting hydraulic cylinder 125 of the hydraulic lifting mechanism 20. Control solenoid valve 121, brake pedal motor 14 for , And, like the parking brake lever motor 146 is connected.

  The brake pedal motor 145 is an actuator for moving the brake pedal 251 to a stepping position where the brake is applied to the left and right rear wheels 4. The parking brake lever motor 146 is an actuator for pulling up (moving) the parking brake lever 254 to the raised position where the parking brake is engaged.

  Further, the controller 200 includes various input-related sensors and switches, that is, a steering potentiometer 210, a forward / reverse potentiometer 211, a main transmission output shaft rotation sensor 212, a vehicle speed sensor 213, a pendulum type rolling sensor 214, and a potentiometer type working unit. Position sensor 215, potentiometer type lift angle sensor 216, potentiometer type rear cover sensor 217, 4WD mode switch 218, double speed mode switch 219, brake pedal switch 220, auto brake switch 221, main transmission potentiometer 222, position lever sensor 223, Working depth setter 224, PTO clutch switch 225, maximum speed setting dial 226, SCV changeover switch 227, manual tilt switch 228, automatic lift switch 229, lift fine adjustment switch 230, auxiliary gear change switch 231, inclination setting dial 232, highest ascent position setting dial 233, lower position setting dial 234, sensitivity changeover switch 235, engine characteristic changeover switch 236, correction switch 237, forced reverse rise switch 238, speed changeover A switch 239, an attitude detection switch 311 and the like are connected.

  The steering potentiometer 210 is for detecting the amount of rotation (steering angle) of the steering handle 9. The forward / reverse potentiometer 211 is for detecting the operation position of the forward / reverse switching lever 252. The main transmission output shaft rotation sensor 212 is for detecting the output rotational speed of the main transmission output shaft 36. The vehicle speed sensor 213 is for detecting the rotational speed (traveling speed) of the front and rear wheels 3 and 4.

  The rolling sensor 214 is for detecting the left-right inclination angle of the traveling machine body 2. The working unit position sensor 215 is for detecting a relative left-right inclination angle of the rotary tiller 15 with respect to the traveling machine body 2. The lift angle sensor 216 is for detecting the rotation angle of a lift arm 193 (see FIG. 1) that connects the hydraulic lifting mechanism 20 and the left and right lower links 21. The rear cover sensor 217 is for detecting the vertical rotation angle of the tilling rear cover 195 (see FIG. 1 and FIG. 2) that rotates up and down as the tillage depth of the rotary tiller 15 fluctuates.

  The 4WD mode switch 218 is for switching the 4WD hydraulic solenoid valve 80. The double speed mode switch 219 is for switching the double speed hydraulic solenoid valve 82. The brake pedal switch 220 is for detecting whether or not the brake pedal 251 is depressed. The auto brake switch 221 is for switching the auto brake solenoid valves 67a and 67b.

  The main transmission potentiometer 222 is for detecting the operation position of the main transmission lever 290. The position lever sensor 223 is for detecting the operation position of the working unit position lever 300 for manually changing and adjusting the height position of the rotary tiller 15. The tilling depth setting device 224 is of a dial type for presetting a target tilling depth of the rotary tiller 15. The PTO clutch switch 225 is for switching the power transmission from the PTO shaft 23 to the rotary tiller 15 by operating the PTO clutch 100 on and off.

  The maximum speed setting dial 226 is for presetting the maximum traveling speed of the traveling machine body 2. The SCV changeover switch 227 is for switching and driving a sub-control valve (not shown) provided on the side of the mission case 17. The sub-control valve is for controlling supply of hydraulic oil to other working parts such as a front loader that is retrofitted to the tractor 1. The tilt manual switch 228 is for manually changing and adjusting the left and right tilt angle of the rotary tiller 15. The automatic raising / lowering switch 229 is for forcibly raising / lowering the rotary tiller 15 to a predetermined height. The elevation fine adjustment switch 230 is for finely adjusting the height position of the rotary tiller 15. The auxiliary transmission changeover switch 231 is for switching the output range of the traveling auxiliary transmission gear mechanism 30 between a low speed and a high speed.

  The inclination setting dial 232 is for setting in advance a target left / right inclination angle of the rotary tiller 15 relative to the traveling machine body 2. The highest rise position setting dial 233 is for setting the highest rise position of the rotary tiller 15. The lowered position setting dial 234 is for setting a position at which the rotary tiller 15 switches from a high speed descent to a low speed descent to reduce the landing impact. The sensitivity changeover switch 235 is for changing / adjusting the sensitivity of the tiller depth automatic control of the rotary tiller 15. The engine characteristic changeover switch 236 is for switching characteristics such as output and torque of the engine 5. The correction switch 237 is for correcting the automatic horizontal control of the rotary tiller 15 in a plurality of stages.

  The reverse forcible lift switch 238 is for forcibly raising the rotary tiller 15 to a predetermined height when the forward / reverse switching lever 252 is moved backward. The speed changeover switch 239 is for changing / adjusting the traveling speed during turning and reverse travel. The posture detection switch 311 is of a limit switch type for detecting whether a right armrest 271 to be described later is in the uppermost rotation posture shown by a one-dot chain line in FIG.

(5). Next, the structure of the control seat 8 and its surroundings will be described with reference to FIGS.

  As shown in FIGS. 7 and 8, a steering column 245 that surrounds the rear side of the engine 5 is disposed in front of the control seat 8 in the cabin 7. From the upper surface of the steering column 245, a handle shaft 246 protrudes obliquely upward and backward. The steering handle 9 having a substantially round shape in plan view is attached to the upper end of the handle shaft 246. In this case, since the substantially annular steering wheel 247 and the handle shaft 246 in the steering handle 9 are substantially orthogonal to each other in a side view, the steering wheel 247 is inclined obliquely backward and downward at an angle θ with respect to the horizontal. (See FIG. 8).

  A frame member 260 is attached to the lower part of the control seat 8 in the cabin 7. The frame member 260 is mounted on the rear cowl 261 that covers the upper side of the transmission case 17 via a pair of left and right moving guide rail means 262 so that the position of the frame member 260 can be adjusted along the traveling direction of the traveling machine body 2 (slidable back and forth). Yes.

  The left and right movement guide rail means 262 includes a fixed side rail 263 fixed on the rear cowl 261 and a movable side rail 264 fixed on the lower surface of the frame member 260. In this case, by fitting the movable side rail 264 to the fixed side rail 263 so as to be slidable back and forth, the frame member 260 and thus the control seat 8 are moved from the last seat position (see the solid line state in FIGS. 7 and 8) to the frontmost seat position (see FIG. 7 and FIG. 8). It can be slid back and forth within the range of the sliding stroke SS up to the two-dot chain line state in FIGS.

  Although not shown in detail, a rotary seat adjustment lever is disposed between the frame member 260 and the rear cowl 261. By rotating the seat adjusting lever, the engaging claw of the seat adjusting lever is engaged with and disengaged from a plurality of engaging recesses formed in the left and right inner sides of the fixed side rail 263 and the movable rail 264, thereby controlling the control seat 8. The front and rear positions of can be changed and adjusted in stages. The engaging claw is always urged in the engaging direction by a spring member.

  On the left and right sides of the control seat 8, armrest devices 265 and 266 for placing the arm and elbow of the operator seated on the control seat 8 are provided. These armrest devices 265 and 266 are basically the same except that the shapes of the armrests 271 and 272 that support the operator's arms and elbows are slightly different. Here, the structure of the right armrest device 265 on the right side of the control seat is used. I will explain as a representative.

  The right armrest device 265 includes a thick bracket member 270 erected on the right side of the frame member 260, and a hollow arm arm 271 that is mounted in the upper part of the bracket member 270 and is long in the longitudinal direction. The bracket member 270 is configured to be position-adjustable (possible to slide back and forth) along the traveling direction (front and rear direction) of the traveling machine body 2 independently of the front and rear slide of the control seat 8.

  In the embodiment, two adjustment groove holes 269 extending along the front-rear direction are formed on the left and right sides of the frame member 260. Then, the bracket member 270 and the right armrest device 265 are attached to the adjustment groove by fastening the bracket member 270 to the right side of the frame member 260 from the outside with the bolts 273 and nuts 274 inserted into the adjustment groove holes 269. Within the range of the movable stroke SA of the hole 269, it can slide back and forth with respect to the control seat 8. In other words, the right armrest device 265 slides back and forth with respect to the control seat 8 within the range of the movable stroke SA from the last position (see the solid line state in FIG. 9) to the foremost position (see the two-dot chain line state in FIG. 9). It is possible.

  If the armrest devices 265 and 266 are configured to be movable back and forth in this manner, the front and back positions of the armrest devices 265 and 266 can be adjusted according to the physique and work posture of the operator seated on the control seat 8, so that the operator's arm can be accurately positioned. I can support it.

  Here, in FIG. 7 and FIG. 8, the position of the right armrest device 265 indicated by the solid line with respect to the control seat 8 is the last position, and the control seat of the right armrest device 265 indicated by the two-dot chain line. The position for 8 is when it is in the forefront position. That is, the position of the right armrest device 265 indicated by the solid line in FIGS. 7 and 8 is the position moved most backward in consideration of the front-rear slide of the control seat 8, and the right armrest indicated by the two-dot chain line The position of the device 265 is a position moved most forward in consideration of the longitudinal slide of the control seat 8.

  As can be seen from these drawings, the front end of the right armrest 271 and the rear end of the steering column 245 are steered in the plan view and the side view, regardless of the front and rear sliding positions of the right armrest device 265 and the control seat 8. It is set so as to be located within the range AR between the front end of the seat 8 (except when the right armrest 271 is in the uppermost rotation posture described later (refer to the one-dot chain line state in FIG. 9)). In other words, the movable stroke SA of the right armrest device 265 is sized so that the front end of the right armrest 271 does not deviate from the aforementioned range AR regardless of the front / rear sliding position of the control seat 8.

  When such a configuration is adopted, the front part of the right armrest 271 is always close to the steering handle 9 in plan view and side view, so that the hand can be smoothly transferred from the right armrest to the steering handle 9. There are advantages.

  On the other hand, the lower rear portion of the right armrest 271 is pivotally attached to the upper portion of the bracket member 270 so as to be able to undulate (up and down) by a pivot shaft 275 that is laterally laterally oriented. For this reason, the right armrest 271 can be flipped up and turned around the pivot shaft 275 as a fulcrum (rotation center) (see the one-dot chain line state in FIG. 9).

  Further, the right armrest 271 is configured to be capable of adjusting the rotation posture by the undulating rotation around the pivot shaft 275 in a plurality of stages (four stages in the embodiment). In this case, a bracing arm 276 is disposed between the right armrest 271 and the bracket member 270. One end portion (upper end portion) of the bracing arm 276 is pivotally attached to the middle portion of the right armrest 271 by a pivot pin 277 that is laterally directed laterally. At the other end (lower end) of the bracing arm 276, a horizontally long locking pin 278 protrudes leftward and rightward inward.

  On the other hand, the bracket member 270 is formed with a long groove hole 279 extending in the vertical direction and a plurality of positioning groove holes 280 (four in the embodiment) extending obliquely forward and downward from the long groove hole 279. By inserting the locking pin 278 of the bracing arm 276 into each positioning groove hole 280, the bracing arm 276 exerts a stretching action, and the right armrest 271 is held in a rotational posture corresponding to each positioning groove hole 280. . In the right armrest 271 (in a base 281 to be described later), a limit switch type posture detection switch 311 for detecting whether or not the right armrest 271 is in the highest rotation posture is provided in association with the pivot shaft 275. .

  The rotation posture of the right armrest 271 in the embodiment is the uppermost rotation posture (see FIG. 9) that extends obliquely forward and upward from the lowest rotation posture (see the solid line state in FIG. 9) that is substantially horizontal with respect to the seating surface of the control seat 8. 4 levels up to the one-dot chain line state). However, the uppermost rotation posture of the right armrest 271 is a posture when the operator releases the right armrest 271 so as not to get in the way when getting on and off the control seat 8, and is a normal posture (rotation when resting with the arm rested). Not posture). In the embodiment, the normal posture of the right armrest 271 is assumed to be a three-step rotational posture excluding the above-described uppermost rotational posture.

  If such a configuration is adopted, the rotational posture of the right armrest 271 can be adjusted stepwise according to the physique and working posture of the operator seated on the control seat 8, so that the operator's arm can be supported accurately or hit the knee. Can be set to not. In addition, combined with the front / rear slide position adjustment function of the control seat 8 and the right armrest device 265, it is effective in reducing the fatigue of the operator due to long-time work. Note that the right armrest 271 may be capable of adjusting its rotation posture steplessly.

(6). Detailed Structure of Right Arm Rest Next, the detailed structure of the right arm rest 271 will be described with reference to FIGS.

  As shown in FIGS. 7 and 11, the right armrest 271 includes a base portion 281 that is long in the front-rear direction, an extension portion 282 that extends forward from the base portion 281, and a front portion of the base portion 281 (also a rear portion of the extension portion 282). And a branching portion 283 branched in a direction away from the control seat 8 (right direction in the embodiment). The extension part 282 and the branch part 283 constituting the front part of the right armrest have a bifurcated shape in plan view, and the right armrest 271 as a whole has a substantially Y shape in plan view.

  As shown in FIG. 8, the right armrest 271 is bent in a substantially square shape when viewed from the side, with the connecting portion of the base portion 281 and the extending portion 282 as a boundary. For this reason, the extension part 282 and the branch part 283 are in a form extending obliquely upward and forward. When the right armrest 271 is in a normal posture (three-step rotational posture) other than the highest rotational posture, the upper surfaces of the extending portion 282 and the branching portion 283 are inclined rearward and downward at an angle θ with respect to the horizontal. The upper surface of the steering wheel 247 is set so as to be substantially flush with the upper surface of the steering wheel 247 (FIG. 8 shows only the state of the lowest rotation posture).

  The upper surface of the right armrest 271 extending from the rear side of the extending portion 282 to the base portion 281 is a stepped portion 284 that is recessed downward. The step portion 284 includes a working depth setting device 224, an inclination setting dial 232, a maximum raising position setting dial 233, a lowering position setting dial 234, a sensitivity changeover switch 235, a correction switch 237, and a reverse drive. An hourly forced increase switch 238, an engine characteristic changeover switch 236, a speed changeover switch 239, and the like, which are examples of traveling system operation means, are arranged. Switches 232 to 239 other than the tilling depth setting device 224 are covered with a pair of left and right upper surface lids 285a and 258b configured to be openable and closable. The operator usually puts his arm and elbow on the top lids 285a and 285b. The upper surface of the tilling depth setting device 224 is set to be lower than the upper surfaces of the extending portion 282 and the upper surface lids 285a and 285b (see FIGS. 8 to 10 and 12).

  On the other hand, the bifurcated portion between the extending portion 282 and the branching portion 283 is a concave portion 286 that is recessed along the side portion of the little finger side of the hand placed on the portion, and on the upper surface lids 285a and 285b ( It is set so that the side of the little finger side of the hand can be placed exactly with the arm placed on the right armrest 271 (see FIGS. 11 and 12).

  On the left side of the upper surface of the extension portion 282 in the right armrest 271, a protruding portion 287 having an upward convex curved shape (kamaboko shape) is integrally formed in a side view. Further, the projecting portion 287 is provided with a main transmission lever 290 as a main transmission operating body constituting the traveling system operation means so as to be able to tilt forward and backward.

  As shown in detail in FIG. 10, the main transmission lever 290 of the embodiment is attached to a lever shaft 291 that can be tilted back and forth around a lateral pin shaft 293 disposed in the extending portion 282, and to the tip of the lever shaft 291. And a picked portion 292. A slit groove 288 is formed in the protruding portion 287 along a curved ridge line extending in the front-rear direction, and the lever shaft 291 passes through the slit groove 288. A knob 292 is attached to the tip of the lever shaft 291 protruding from the protruding portion 287.

  Therefore, when the knob 292 is moved along the curved ridgeline, the lever shaft 291 tilts back and forth along the slit groove 288. Further, the forward / backward tilting of the lever shaft 291 and thus the main transmission lever 290 is restricted within the range of the stroke of the slit groove 288. A main transmission potentiometer 222 for detecting the operation position of the main transmission lever 290 (lever shaft 291) is provided in the extension portion 282 in association with the pin shaft 293.

  The main transmission lever 290 of the embodiment is formed so as to be positioned above the upper surface of the steering wheel 247 in a side view regardless of the rotation posture of the right armrest 271 (the lowest rotation in FIG. 8). Shown only for posture). Further, as shown in FIGS. 11 and 12, the arrangement position of the main transmission lever 290 and the formation position of the protruding portion 287 of the extending portion 282 are determined by the hand in the concave portion 286 between the extending portion 282 and the branching portion 283. The position is set such that the knob 292 can be operated with the thumb while the little finger side is placed.

  On the right side of the upper surface of the extension portion 283 (next to the protruding portion 287), a maximum speed setting dial 226 and an auxiliary transmission changeover switch 231 that are examples of traveling system operation means, and an SCV changeover switch that is an example of work system operation means. 227, an inclination manual switch 228, an automatic elevating switch 229, and an elevating fine adjustment switch 230 are arranged.

  On the upper surface of the branch portion 283 in the right armrest 271, an upward convex curved (kamaboko-shaped) protruding portion 297 is integrally formed in a side view. A flange portion 299 having a substantially arc shape in a side view protruding upward from the upper surface (curved ridgeline) of the protruding portion 297 is formed on the side surface of the protruding portion 297 facing the extending portion 282. Further, the projecting portion 297 is provided with a working part position lever 300 as a working part raising / lowering operating body constituting the working system operating means so as to be able to be tilted back and forth.

  As shown in detail in FIG. 10, the working unit position lever 300 according to the embodiment includes an elevating lever shaft 301 that can be tilted back and forth around a lateral support shaft 303 arranged in the branching portion 283, and a tip of the elevating lever shaft 301. And a lifting knob 302 attached to the head. A slit groove 298 is formed in the protruding portion 297 along a curved ridge line extending in the front-rear direction, and the elevating lever shaft 301 passes through the slit groove 298. A knob 302 is attached to the tip of the lift lever shaft 301 protruding from the protruding portion 297.

  Therefore, when the knob 302 is moved along the curved ridgeline, the lever shaft 301 tilts back and forth along the slit groove 298. A position lever sensor 223 that detects the operation position of the working unit position lever 300 (lever shaft 301) is provided in the branch unit 283 in association with the support shaft 303. The slit groove 298 is fitted with a restricting claw piece 304 for restricting the lever shaft 301 and thus the working portion position lever 300 from tilting back and forth.

  The working portion position lever 300 of the embodiment can be tilted back and forth between a substantially vertical posture (see the solid line and broken line state in FIG. 10) and a forward posture (see the one-dot chain line state in FIG. 10). When the working unit position lever 300 is tilted forward, the control solenoid valve 121 (see FIGS. 5 and 6) is switched to drive the single-acting hydraulic cylinder 125 to shorten, and the lift arm 193 (see FIG. 1) is directed downward. Rotate. As a result, the rotary cultivator 15 moves down via the lower link 21. On the contrary, when the working unit position lever 300 is tilted backward, the control solenoid valve 121 is switched to drive the single-acting hydraulic cylinder 125 to extend and rotate the lift arm 193 upward. As a result, as a result, the rotary tiller 15 moves up via the lower link 21.

  Further, like the main transmission lever 290, the working unit position lever 300 is also formed so as to be positioned above the upper surface of the steering wheel 247 in a side view, regardless of the rotation position of the right armrest 271. (In FIG. 8, only shown in the lowest rotation posture).

  The positional relationship between the main transmission lever 290 and the working unit position lever 300 may be opposite to that in the above-described embodiment. That is, the working part position lever 300 (working system operating means) may be arranged on the extending part 282 side, and the main transmission lever 290 (traveling system operating means) may be arranged on the branching part 283 side.

  As shown in FIGS. 7 to 9, 11, and 12, a recessed portion 306 that is recessed downward is formed in the branch portion 283 on the base side behind the working portion position lever 300 (protruding portion 297). Yes. The position of the depressed portion 306 is such a position that the wrist and the like hardly overlap each other in plan view with the arm placed on the upper surface lids 285a and 285b (on the right armrest 271). In the depression 306, a PTO clutch switch 225 is disposed as a PTO operating body for operating the PTO clutch 100 to be turned on and off, and for interrupting the transmission of power from the PTO shaft 23 to the rotary tiller 15.

  When the PTO clutch switch 225 is rotated clockwise in plan view while pressing the switch once, the PTO clutch switch 225 is locked at the pressed position, and the power transmission from the PTO shaft 23 to the rotary tiller 15 is brought into the connected state, and further pressed again. This is a push switch that returns to the original position and shuts off power transmission from the PTO shaft 23 to the rotary tiller 15. The upper surface of the PTO clutch switch 225 in the embodiment is set to be slightly higher than the upper surfaces of the upper surface lids 285a and 285b (see FIGS. 8 to 10 and 12).

  When configured as described above, on the upper surface of the right armrest 271 located beside the operator seated on the control seat 8, the main transmission lever 290 and various switches 226, 231, 236, 239 constituting the traveling system operation means, Since the working unit position lever 300 and the various switches 224, 225, 227 to 230, 232 to 238 constituting the working system operating means are arranged together, the operability (handleability) is excellent.

  Further, the front portion of the right armrest 271 is formed in a bifurcated shape in plan view including an extending portion 282 and a branching portion 283, and includes a main speed change lever 290, a maximum speed setting dial 226 as a part of traveling system operation means, Sub-shift switch 231, working unit position lever 300 as part of the work system operating means, tilling depth setting device 224, PTO clutch switch 225, SCV switch 227, manual tilt switch 228, automatic lift switch 229, and lift Since the fine adjustment switch 230 is disposed on the upper surface of the extension portion 282 and the upper surface of the branch portion 283, the traveling system operation means and the work system operation means can be operated with the arm placed on the right armrest 271; The operability of these operating means is further improved.

  In particular, in the embodiment, the main transmission lever 290 as a part of the traveling system operation means is arranged on the extension part 282 side, and the working part position lever 300 as a part of the work system operation means is arranged on the branch part 283 side. Therefore, if the hand on the right armrest 271 is moved in the left-right direction with the elbow as a fulcrum, the hand can easily reach the main transmission lever 290 and the working unit position lever 300. Therefore, there is an advantage that the main speed change lever 290 or the work part position lever 300 can be operated with only the hand on the right armrest 271.

  In addition, the front portion of the right armrest 271, that is, the extending portion 282 and the branching portion 283 are bent and extended forward and obliquely upward in a side view, so that when the arm is placed on the right armrest 271 The main transmission lever 290 on the extension part 282 and the working part position lever 300 on the branch part 283 can be operated with a natural hand posture without bending the wrist downward. For this reason, the operability of the main transmission lever 290 and the working unit position lever 300 is remarkably improved and contributes to the stable support of the hand.

  In addition, if the side of the little finger side of the hand is placed on the right armrest 271 with the arm placed on the right armrest 271 in the forked portion (recess 286) between the extending portion 282 and the branching portion 283, not only the arm but also the hand Since it can support stably, the fatigue of the operator by long-time work can be reduced. In particular, the concave portion 286 between the extending portion 282 and the branching portion 283 is excellent in holdability when the side portion on the little finger side of the hand is placed, and can exert a high effect on stable support of the hand.

  In addition, when the right armrest 271 is in a normal posture (a three-step rotational posture) other than the uppermost rotational posture, the upper surfaces of the extending portion 282 and the branching portion 283 are inclined rearward and downward at an angle θ with respect to the horizontal. The upper surface of the inclined steering wheel 247 is set to be substantially flush with the upper surface of the steering wheel 247 when viewed from the side. For this reason, the hand placed on the right armrest 271 can be smoothly moved to the steering wheel 247, and the operation of the tractor 1 is facilitated.

  Furthermore, the main transmission lever 290 and the working unit position lever 300 of the embodiment are formed so as to be positioned above the upper surface of the steering wheel 247 in a side view, regardless of the rotation posture of the right armrest 271. Therefore, the arrangement positions of the main transmission lever 290 and the working unit position lever 300 are closer to the operator than the steering wheel 247. For this reason, it contributes to improving the operability of the main transmission lever 290 and the working unit position lever 300.

  In the embodiment, a flange portion 299 having a substantially arc shape in a side view protruding upward from the upper surface (curved ridge line) of the protruding portion 297 is formed on the side surface facing the extending portion 282 of the protruding portion 297 of the branching portion 283. ing. For this reason, the presence of the collar portion 299 can prevent the hand placed on the concave portion 286 from hitting the working portion position lever 300 on the branch portion 283. Therefore, it is possible to reliably reduce the risk of inadvertently touching the working portion position lever 300 on the branching portion 283 with the side portion on the little finger side of the hand placed in the concave portion 286, which is effective in preventing erroneous operation.

  Further, the main transmission lever 290 of the embodiment is disposed in the extending portion 282 of the right arm rest 271 and the side portion on the little finger side of the hand is placed in the concave portion 286 between the extending portion and the branching portion. The main transmission lever 290 is very easy to operate because it can be operated with the thumb in the mounted state, and a high effect can be exhibited in improving the traveling operability in the tractor 1.

  On the other hand, the working unit position lever 300 can be tilted back and forth between a substantially vertical posture (see the solid and broken line states in FIG. 10) and a forward posture (see the one-dot chain line state in FIG. 10). When the head position lever 300 is tilted forward, the rotary tiller 15 is lowered, and when the head position lever 300 is tilted backward, the rotary tiller 15 is lifted. The movement of 300 by manual operation and the up-and-down movement of the rotary cultivator 15 match the operator's feeling. For this reason, when the working unit position lever 300 is manually operated, the lifted state of the rotary tiller 15 can be easily grasped from the operating state of the working unit position lever 300.

  In the embodiment, since the PTO clutch switch 225 as the PTO operating body is arranged on the base side behind the working unit position lever 300 in the branching portion 283, when the rotary tiller 15 is stopped urgently, the PTO clutch The arrangement position of the switch 225 is easy to grasp. In addition, the position of the PTO clutch switch 225 is the position where the wrist is placed on the right arm rest 271 and the wrist and the like hardly overlap each other in plan view. Inadvertently hitting 225 (not disturbing), erroneous operation of the PTO clutch switch 225 can be reduced.

  Further, a plowing depth setting device 224 is disposed on a downward concave step 284 on the rear side of the extending portion 282 in the right armrest 271, and the upper surface of the plowing depth setting device 224 is formed by the extending portion 282 and the upper surface lid. Since it is set so as to be lower than the upper surfaces of 285a and 285b, the arm and elbow are placed on the right armrest 271 while the plowing depth setting device 224 having a relatively high operation frequency is provided on the right armrest 271. Even if it is still on, it is possible to reduce the risk of inadvertently touching the tilling depth setting device 224. Accordingly, erroneous operation of the tilling depth setting device 224 can be significantly reduced or prevented.

(7). Next, the structure of the safety mechanism for preventing inadvertent driving of the tractor 1 will be described with reference to FIGS. 6 and 13.

  As shown in detail in FIG. 13, the positive terminal of the battery 202 includes an input terminal of the key switch 201, one end of a normally-open switch unit 313 that constitutes the starter relay 312, and a normally-open type that constitutes the alarm relay 315. The switch unit 316 is branched and connected to one end of the switch unit 316. The other end of the switch unit 313 in the starter relay 312 is connected to the starter 203. The other end of the switch unit 316 in the alarm relay 315 is connected to the alarm buzzer 318. The negative terminal of the battery 202 is grounded.

  The key switch 201 is configured to be switchable to three terminal positions, that is, an engine stop terminal 241, an energization terminal 242, and a start terminal 243 by rotating a predetermined key inserted into the keyhole. An input terminal of a limit switch type attitude detection switch 311 is connected to the start terminal 243 of the key switch 201. The movable contact 311c constituting the posture detection switch 311 is a first output of the posture detection switch 311 when the right armrest 271 is in a normal posture (three stages) other than the highest rotation posture indicated by a one-dot chain line in FIGS. When the right armrest 271 contacts the terminal 311a and is in the uppermost rotation posture, it is configured to contact the second output terminal 311b of the posture detection switch 311.

  A first output terminal 311 a of the attitude detection switch 311 is connected to one end of a coil unit 314 that constitutes the starter relay 312. The other end of the coil portion 314 in the starter relay 312 is grounded. The second output terminal 311 b of the posture detection switch 311 is connected to one end of a coil unit 317 that constitutes the alarm relay 315. The other end of the coil portion 317 in the alarm relay 315 is grounded. Although a detailed circuit diagram is not shown, as described above, the attitude detection switch 311 is also electrically connected to the controller 200 as a control means (see FIG. 6).

  In the above configuration, when the key switch 201 is turned to the position of the start terminal 243 when the right arm rest 271 is in a normal posture other than the highest rotation posture, the movable contact 311c of the posture detection switch 311 contacts the first output terminal 311a. Therefore, the current from the battery 12 flows into the coil unit 314 of the starter relay 312, the coil unit 314 enters an excited state, and the switch unit 314 of the starter relay 312 enters a closed state (conducting state). As a result, the starter 203 is activated by energization from the battery 202, and the engine 5 is started.

  When the hand is released from the key switch 201 after the engine 5 is started, the key switch 201 returns to the position of the energizing terminal 242 by the elastic biasing force of a spring (not shown), and the power supply from the battery 202 to the entire tractor 1 and the engine 5 is maintained. When the key switch 201 is turned to the position of the engine stop terminal 241, the power supply from the battery 202 is stopped and the drive of the engine 5 is stopped.

  On the other hand, when the key switch 201 is turned to the position of the start terminal 243 when the right armrest 271 is in the highest rotation posture, the movable contact 311c of the posture detection switch 311 is in contact with the second output terminal 311a. Current does not flow into the coil section 314 of the starter relay 312, and the switch section 314 of the starter relay 312 maintains the open state (cut-off state). For this reason, the energization from the battery 202 to the starter 203 is cut off, the starter 203 does not operate, and as a result, the engine 5 does not start.

  That is, when the power is turned on, if the right armrest 271 is in the uppermost rotation posture, the engine 5 is not started, and consequently the rear wheel 4 and the rotary tiller 15 are not driven. For this reason, when the operator gets on and off, the rear wheel 4 and the rotary tiller 15 suddenly come into contact with the main transmission lever 290 and the working unit position lever 300 on the right armrest 271 in the most pivoted position. It does not move, and the safety of the tractor 1 is improved.

  In the case where the right armrest 271 is in the uppermost rotation posture, when the key switch 201 is turned to the position of the start terminal 243, the current from the battery 12 flows into the coil unit 317 of the alarm relay 315, and the coil unit 317 is excited. The switch unit 316 of the alarm relay 315 enters a closed state (conductive state). As a result, the alarm buzzer 318 sounds when the battery 202 is energized. Therefore, the alarm buzzer 318 can alert the operator, and can accurately notify the operator that the engine 5 cannot be started because the right armrest 271 is in the uppermost rotation posture.

  If the right armrest 271 is returned to the normal posture, the movable contact 311c of the posture detection switch 311 moves away from the second output terminal 311b and contacts the first output terminal 311a. The switch unit 316 of the relay 315 is opened, and the alarm buzzer 318 stops sounding.

  Now, when the right armrest 271 is set to the uppermost rotation posture while the engine 5 is being driven, the safety control by the controller 200 and the electronic governor controller 204 is executed as follows, for example (see FIG. 6).

  That is, when the posture detection switch 311 detects that the right armrest 271 is in the uppermost rotation posture while the engine 5 is being driven, the controller 200 is operated by the operation of the switching valve 124 by the hydraulic oil from the proportional control valve 123. The main transmission hydraulic cylinder 190 is driven to forcibly hold the hydraulic continuously variable transmission 29 in a neutral state in which the inclination angle of the pump swash plate 159 with respect to the axis of the main transmission input shaft 27 is substantially zero.

  At this time, the electronic governor controller 204 drives the throttle solenoid 208 to automatically adjust the position of a fuel adjustment rack (not shown) provided in the governor 205 to the idling position, and the engine 5 has a low rotational speed. Forced to keep idling.

  Further, the controller 200 drives the PTO clutch cylinder 105 by the operation of the PTO clutch hydraulic solenoid valve 104 to disengage the PTO clutch 100 (power cut-off state), and transmits power from the PTO shaft 23 to the rotary tiller 15. Is forcibly shut off.

  In addition to these, the controller 200 moves the brake pedal 251 to the depressed position by driving the brake pedal motor 145 to turn on the pair of left and right brakes 65a and 65b, and drives the parking brake lever motor 146. The parking brake lever 254 is moved to the raised position to enter the engaged state, and the brake pedal 251 and the parking brake lever 254 are held in an engaged state, whereby the left and right rear wheels 4 are applied with the brakes 65a and 65b ( Maintain the braking state.

  That is, in the embodiment, when the right armrest 271 is set to the uppermost rotation posture while the engine 5 is being driven, (1) the hydraulic continuously variable transmission 29 is held in a neutral state, and (2) the engine 5 is in an idling state. And (3) interrupting power transmission from the PTO shaft 23 to the rotary tiller 15 (hereinafter referred to as PTO power transmission system), and (4) maintaining the left and right rear wheels 4 in a braking state. The operation is set to be executed under the control of the controller 200 and the electronic governor controller 204.

  According to the above configuration, even when the engine 5 is being driven, the driving of the rear wheel 4 and the rotary cultivator 15 can be stopped all at once by simply bringing the right armrest 271 to the highest rotation posture. It will also play a role as an emergency stop switch means, and can exhibit a high effect in improving the safety of the tractor 1.

  Now, when returning the right armrest 271 to the state before the uppermost rotational posture (hereinafter referred to as the original state), the right armrest 271 is first returned to the normal posture. If the four emergency operations described above are canceled at once, the traveling speed of the traveling machine body 2 suddenly returns to its original value, which is understood to be problematic in terms of traveling safety. For this reason, in the embodiment, it is set to return to the original state by the control of the controller 200 and the electronic governor controller 204 by performing the following procedure.

  That is, first, as described above, the right armrest 271 is returned to the normal posture. At this stage, the four emergency operation states described above are maintained as they are. Next, the parking brake lever 254 is lowered from the raised position to the lowered position, and only the braking state of the rear wheel 4 is released (the hydraulic continuously variable transmission 29, the engine 5 and the PTO power transmission system maintain the emergency operation state). . The parking brake lever motor 146 of the embodiment is configured to move the parking brake lever 254 only to the raised position and not return to the lowered position. The brake pedal 251 is automatically returned to a normal position (also referred to as a non-depressed position or a non-depressed position) by a restoring force of an urging means (not shown) such as a spring or an air cylinder. .

  Next, the forward / reverse switching lever 252 that has been operated to be tilted forward or backward is once returned to the neutral state, and then the forward / backward switching lever 252 is again tilted to the forward or reverse side. As a result, the emergency operation state of the hydraulic continuously variable transmission 29, the engine 5, and the PTO power transmission system is released.

  The control process at this stage will be described in detail. The brake pedal switch 200 detects that the brake pedal 251 has returned to the normal position, and the forward / reverse switching lever 252 temporarily moves forward or backward after passing through the neutral position. The fact that it has moved to the position is detected by the forward / reverse potentiometer 211.

  The controller 200 having acquired the detection information of the brake pedal switch 200 and the forward / reverse potentiometer 211 drives the main transmission hydraulic cylinder 190 by the operation of the switching valve 124 by the hydraulic oil from the proportional control valve 123, and the main transmission input shaft 27. The pump swash plate 159 with respect to the axis is returned to the original inclination angle (inclination angle before the right armrest 271 is moved to the highest rotation position), and the hydraulic continuously variable transmission 29 is switched to a state where the shift power can be output.

  At this time, the electronic governor controller 204 drives the throttle solenoid 208 so that the position of the fuel adjustment rack (not shown) provided in the governor 205 is the original position (the position before the right armrest 271 is in the highest rotation position). The engine speed is returned to the original state.

  Further, the controller 200 drives the PTO clutch cylinder 105 by the operation of the PTO clutch hydraulic solenoid valve 104 to put the PTO clutch 100 into the engaged state (power connection state), and transmit power from the PTO shaft 23 to the rotary tiller 15. Connect.

  As is apparent from the above description, in the embodiment, the right armrest 271 is returned to the normal posture, the parking brake lever 254 is lowered from the raised position to the lowered position, and then the forward / reverse switching lever 252 is once returned to the neutral state. The tractor 1 returns to the original state by stepping on the forward / backward switching lever 252 again and operating it.

  Therefore, the traveling speed of the traveling machine body 2 does not return abruptly only by returning the right armrest 271 to the normal posture, and careful consideration is given to the safety at the time of return when the right armrest 271 is returned to the normal posture. . In addition, since the driving of the engine 5 itself is not stopped, if the predetermined procedure is performed after the right armrest 271 is returned to the normal posture, the four emergency operations described above are canceled, and the return to the original state is safe. And it can be done smoothly.

(8). Others The present invention is not limited to the above-described embodiment, and can be embodied in various forms. For example, the present invention is not limited to a tractor but can be applied to agricultural machines such as rice transplanters and combines, and special work vehicles such as wheel loaders.

  Further, the armrests 271 and 272 may be provided only on either the left or right side of the control seat 8. When the armrests 271 and 272 are provided on the left and right sides of the control seat 8 as in the above-described embodiment, various operation means may be provided on either the left or right armrests 271 and 272. Furthermore, the engine 5 mounted on the traveling machine body 2 is not limited to a diesel engine, and may be a gasoline engine.

  In addition, the configuration of each unit is not limited to the illustrated embodiment, and various modifications can be made without departing from the spirit of the present invention.

It is a left view of a tractor. It is a top view of a tractor. It is a skeleton figure of a power transmission system. It is a hydraulic circuit diagram of a hydraulic continuously variable transmission. It is a hydraulic circuit diagram of a tractor. It is a functional block diagram of a controller. It is a top view of a cabin. It is a left side sectional view of a cabin. It is a left view of an armrest. It is an expansion left view of an extension part. It is a top view of an armrest. It is the perspective view which looked at the armrest from the diagonally forward upper side. It is an electric circuit diagram of a safety mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tractor 2 Traveling machine body 8 Control seat 9 Control handle 15 Rotary tiller 23 PTO shaft 104 PTO clutch hydraulic solenoid valve 123 Proportional control valve 124 Switching valve 145 Brake pedal motor 146 Parking brake lever motor 200 Controller 208 Throttle solenoid 225 As PTO operation body PTO clutch switch 251 Brake pedal 254 Parking brake lever 265 as parking brake means Right armrest device 266 Left armrest device 270 Bracket member 271 Right armrest 272 Left armrest 281 Base portion 282 Extending portion 283 Branching portion 284 Step portion 286 Recessed portion 290 Main speed change Main transmission lever 300 as operating body Working portion position lever 311 as working portion lifting operation body Posture detection switch

Claims (3)

A work vehicle configured to shift power from an engine mounted on a traveling machine body by a hydraulic continuously variable transmission and transmit the power to a traveling unit and a working unit,
An armrest for placing an operator's arm or hand is disposed on at least one of the left and right sides of the control seat in the traveling body, and traveling system operation means and work system operation means are disposed on the upper surface of the armrest. And
The armrest is rotatable in the vertical direction with the rear end side as a fulcrum, and the rotation posture is configured to be adjustable in a plurality of steps or steplessly.
Work vehicle. A posture detection switch for detecting whether or not the armrest is in the highest rotation posture is provided, and is configured to restrict the start of the engine when the armrest is in the highest rotation posture when the power is turned on. Being
The work vehicle according to claim 1. The hydraulic continuously variable transmission includes an attitude detection switch for detecting whether or not the armrest is in the uppermost rotation attitude, and when the armrest is in the uppermost rotation attitude while the engine is being driven. Is maintained in a neutral state, the engine is in an idling state, power transmission to the working unit is interrupted, and parking brake means for maintaining the traveling unit in a braking state is in an on state. ing,
The work vehicle according to claim 1.

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