JP2006218944A - Shift operation structure of farm working machinery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To carry out shift operation without contact with other object while utilizing the feature excellent in front visibility and easy to drive. <P>SOLUTION: In the farm working machinery, an engine is disposed at the rear side more than a front axle case steerably mounting a front wheel, a transmission case unsteerably mounting a rear wheel and the engine are interlockingly connected, the traveling power taken out from the transmission case is transmitted to the front axle case, and a working device is drivably and liftably connected to a machine rear part. A shift lever 91 operating a shift mechanism provided on the transmission case of the machine rear part is oscillatingly operatably supported around a vertical axis (g) through a shift operating shaft 90 vertically disposed near a steering wheel 11, and the lower end part of the shift operating shaft 90 and the shift operation part of the shift mechanism are interlockingly connected by a connection member 93 disposed through the lower space of the engine. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a speed change operation structure used in a farm work machine such as a small riding rice transplanter.

As a small passenger rice transplanter, for example, as disclosed in Patent Document 1, an engine is arranged behind the front wheel to be steered, and a mission case and engine equipped with a rear wheel that cannot be steered Are connected to each other, and the driving power taken out from the transmission case is transmitted to the front wheels. There is known a configuration in which a shift lever for operating is installed in front of the foot and swings back and forth in the vicinity of the lower part of the steering handle.
JP 2004-180632 A

  The passenger rice transplanter with the above-mentioned fuselage configuration has a large engine bonnet in front of the driver's seat, so it has a good front view and is easy to drive, but the speed change lever is exposed vertically on the step. For this reason, it is easy to come into contact with other objects, and when the operator moves around the steering handle, there is a possibility that the shift lever may be touched and inadvertently operated.

  In order to eliminate such problems, it is conceivable to cover the shift lever with a cover so that it does not come into contact with other objects. However, there is a cover surrounding the shift lever that is swung around the step. It becomes large, and the above-described advantage of reducing the structure in front of the driver seat is impaired.

  The present invention has been made paying attention to such points, and it is a main object of the present invention to make it possible to perform a speed change operation without contact with other objects while taking advantage of the features of good front view and easy driving. It is said.

According to a first aspect of the present invention, an engine is arranged behind a front axle case equipped with front wheels capable of steering operation, and a transmission case equipped with rear wheels that cannot be steered is linked to the engine, and the mission case Agricultural work machine that is configured to transmit the traveling power extracted from the front axle case to the front axle case, and the working device is connected to the rear part of the machine body so as to be driven up and down.
A speed change lever for operating a speed change mechanism provided in the transmission case is supported so as to be swingable around a vertical axis through a speed change operation shaft arranged vertically in the vicinity of the steering handle. The lower end portion and the speed change operation portion of the speed change mechanism are interlocked and connected by a linkage member provided through a space below the engine.

  According to the above configuration, the operating force of the shift lever is transmitted downward through the shift operation shaft arranged in the vertical direction, and then transmitted to the shift operation unit at the rear of the machine body through the linkage member. In this case, since the speed change operation shaft remains standing in a fixed posture and does not change its posture, the speed change operation shaft does not hinder the forward view.

  In addition, the linkage member that interlocks and connects the lower end portion of the speed change operation shaft and the speed change operation portion behind the fuselage is arranged so as to pass through the lower space of the engine, so that the linkage member is deployed without protruding laterally from the fuselage. It will be.

  Therefore, according to the first aspect of the invention, it is possible to operate without contact with other objects while taking advantage of the feature that the forward view is good and easy to drive, and the linking member is compacted below the fuselage without contacting the other objects. A shift operation structure that can be deployed could be constructed.

According to a second invention, in the first invention,
The linking member is disposed through the front axle case.

  According to the above configuration, obstacles on the ground and the like are prevented from approaching and contacting the linking member from below by the front axle case, which is effective in improving the maintainability of the speed change operation system.

According to a third invention, in the first or second invention,
The linking member is provided above the steering mechanism that steers the front wheels.

  According to the above configuration, the upper part of the steering mechanism deployed in the low position of the fuselage is a place where it is difficult for muddy water or the like to fall, and mud adhesion and deposition on the linked member and the member linked to this are suppressed. be able to.

A fourth invention is the invention according to any one of the first to third inventions,
The linkage member is constituted by a push-pull rod.

  According to the above configuration, since the push / pull rod as the linking member is simply moved back and forth and is displaced little in the vertical and horizontal directions, the speed change operation system should be compact with a small arrangement space. Can do.

  The whole side surface of the riding rice transplanter which is an example of the agricultural working machine based on this invention is shown by FIG. 1, and the whole plane is each shown by FIG. This riding rice transplanter is driven to swing up and down by a single-acting hydraulic cylinder 4 at the rear of a four-wheel drive type traveling machine body 3 having a front wheel 1 that can be steered and a rear wheel 2 that cannot be steered. A three-row planting seedling planting device (working device) 6 is connected via a four-link mechanism 5 so as to be movable up and down. The engine 7 is mounted on the rear part of the traveling machine body 3, and a step 8 that covers the engine 7 and the traveling machine body 3 from above is detachably provided. On the left and right sides of the driver's seat 9, there are two spare seedling platforms 100 for placing and storing two spare seedlings on the left side and one on the right side, and standing on the front end of the traveling machine body 3. The steering handle 11 is provided on the upper portion of the center post 10 provided.

  In the seedling planting device 6, three seed mats are placed in parallel, and a seedling base 12 that reciprocally moves back and forth with a fixed stroke, and seedlings are cut out from the lower end of the seedling base 12 by one stock. Three sets of crank-type planting mechanisms 13 for planting, a leveling float 14 for leveling the planting site on the surface, and the like. The leveling float 14 that can swing up and down around the rear fulcrum p and a control valve 15 (described later) that controls the operation of the hydraulic cylinder 4 are mechanically linked to each other, and the control valve is controlled based on the vertical swinging displacement of the leveling float 14. 15 is operated to stably maintain the seedling planting device 6 at the height set with respect to the paddy field regardless of the ups and downs of the traveling machine body 3 or the front / rear tilt, thereby maintaining the planting depth constant. Control is to be performed.

  As shown in FIG. 3, the traveling machine body 3 includes a transmission case 21 that pivotally supports the rear wheel 2 connected to a rear end of a main frame 20 made of a thick pipe material, and a front end of the main frame 20. A front axle case 22 equipped with wheels 1 is connected, and the main frame 20 is a power transmission case through which a front wheel drive shaft 23 that transmits traveling power from the transmission case 21 to the front axle case 22 is inserted. It has the function of.

  As shown in FIG. 5, the engine 7 uses an air-cooled gasoline engine with an output shaft 16 protruding on the left side, and the main frame 20 and the transmission case are in a low-bulk posture with the cylinder axis tilted rearward. 21 and a muffler 18 is mounted on the left side of the engine in an inclined posture that is lowered rearward so that the exhaust is discharged toward the lower rear of the fuselage. The output shaft 16 and the input shaft 17 projecting from the left side of the transmission case 21 are wound and interlocked via a transmission belt 25, and horizontally on the output shaft 16 and the front portion of the transmission case 21 horizontally. A pump driving rotary shaft 26 that is through-supported is wound and interlocked via an auxiliary transmission belt 27. A drain plug 33 is provided on the rear lower surface of the crankcase in the engine 7 so that the oil can be drained from the space below the cylinder portion.

  The transmission belt 25 for main transmission is wound around the output pulley 16a and the input pulley 17a and is tensioned by the tension mechanism 28, and the auxiliary transmission belt 27 is wound around the output pulley 16b and the input pulley 28a. While being rotated, the tension mechanism 29 is tensioned. Both tension mechanisms 28 and 29 urge and swing tension arms 31 and 32 supported by swinging around a common fulcrum shaft 30 by tension springs 66 and 67, respectively. A bolt 68 is attached to the left side surface of the engine 7 as a common spring receiving member that supports the fulcrum shaft 30 and the tension springs 66 and 67 fixed ends. Here, a bolt 68 serving as a spring receiving member is used in which a threaded portion is exposed long, and the fixed side ends of the tension springs 66 and 67 are latched and supported by the threaded portion without moving to the left and right. It is like that.

  The tension mechanism 28 functions as a tension-type main clutch that interrupts transmission of power to the transmission case 21, and the tension arm 31 connects the link mechanism 55 to the stop pedal 19 provided at the right front foot of Step 8. Are interlocked with each other. When the stop pedal 19 is depressed, the tension arm 31 is swung to the relaxation side against the tension spring 66, the power transmission to the transmission case 21 is interrupted, and the driving of the traveling and planting device 6 is stopped. The On the other hand, the tension mechanism 29 of the pump drive system always tensions the auxiliary transmission belt 27. Even if the main clutch is disengaged by operating the pedal, the pump drive is continued and the hydraulic pressure is maintained while the engine 7 is operating. The cylinder 4 can be driven. The tension arm 31 is formed by bending a belt holding piece 31a adjacent to the transmission belt 25, and the transmission belt 25 is moved to the belt holding piece 31a during the main clutch disengagement operation in which the tension arm 31 is swung upward. Thus, the loosened transmission belt 25 is reliably lifted from the output pulley 16a and prevented from rotating together.

  Here, the output shaft 16 of the engine 7 is a camshaft that is rotated by being reduced by a factor of two with respect to the crankshaft 7a, thereby reducing the deceleration load in the transmission case. Further, the output shaft 16 is positioned behind the airframe from the crankshaft 7a, whereby the distance between the output shaft 16 and the input shaft 17 is shortened, and the belt transmission structure is reduced in size. Further, since the output shaft 16 of the engine 7 is a cam shaft, the tension side of the transmission belt 25 and the auxiliary transmission belt 27 becomes the lower side of the belt winding path, and the belt tension side receiving a large load tension is a high heat portion in the engine 7. Since the transmission belt 25 and the auxiliary transmission belt 27 are exposed to a high-temperature atmosphere at an early distance from a certain cylinder portion, they are prevented from extending at an early stage.

  As shown in FIG. 7, a speed control lever 71 interlocked with the carburetor 70 is mounted on the upper portion of the engine 7 so as to be swingable around the vertical axis e, and a link spring 72 is connected to the speed control lever 71. An accelerator lever 73 that is interlocked and connected to the bracket 7 is provided on a bracket 74 provided on the upper surface of the engine 7 so that it can swing around a longitudinal fulcrum f and can be held at an arbitrary operation position by friction at the fulcrum. .

  As shown in FIG. 6, the right side surface of the engine 7 is provided with a cooling air introduction case 75 in which a recoil starter is installed. A starting rope 76 led downward from the front portion of the cooling air introduction case 75 is guided to be wound upward via a guide roller 77, and an operation knob 78 provided at the end of the rope is exposed to the lower right outside of the driver seat 9. The operation knob 78 can be easily pulled and operated in a seated posture. Although a detailed structure is omitted, the pulling operation of the operation knob 78 is allowed only when the stop pedal 19 is depressed, and the traveling machine body 3 may start and move as soon as the engine is started. It has come to be avoided.

  As shown in FIG. 15, the rotary shaft 26 that is always driven via the auxiliary transmission belt 27 is inserted into the casing 15a of the control valve 15 connected to the right side surface of the mission case 21, and embedded in the left side surface of the casing 15a. The oil discharged from the hydraulic pump 79 is sent to an oil passage a formed inside the casing 15a, and the cylinder port c of the control valve 15 (see FIG. 5). And the hydraulic cylinder 4 are connected by piping.

  The hydraulic pump 79 uses the lubricating oil stored in the transmission case 21 as the working oil, and the suction oil passage b is formed in the right side wall of the transmission case 21, and the suction oil is shown in FIG. An oil filter 80 is attached to the front portion of the transmission case 21 so that it can be inserted and removed from below.

  The internal structure of the mission case 21 is shown in FIGS. The engine power transmitted to the input shaft 17 is first branched into a traveling system and a working system, and the traveling system power is transmitted to the transmission shaft 35 after being shifted to three forward speeds and one reverse speed by a gear-type transmission mechanism 34. Thereafter, the gear is transmitted to the horizontally long counter shaft 36, and further transmitted from the counter shaft 36 to the left and right axles 39 via the left and right side clutches 37 and the gear reduction mechanism 38, and from the intermediate portion of the counter shaft 36. Front wheel drive power is extracted from the front wheel drive shaft 23. The speed change mechanism 34 shifts the shift shaft 40 built in the speed change shaft 35 in the axial direction, thereby moving forward three sets of regular meshing gear pairs and one set of regular meshing gear pairs for reverse travel. By selectively engaging the key 40a with any one of these, a forward three-stage shift and a reverse one-stage shift are performed.

  As shown in FIG. 8, the transmission case 21 includes a case body 21A connected to the rear end of the main frame 20, and left and right cover cases 21B detachably bolted to the left and right ends of the case body 21A. The case main body 21A itself has a structure in which the left and right divided case portions 21Aa and 21Ab are joined and bolted together. Then, both ends of the counter shaft 36 are supported by the left and right cover cases 21B, and the left and right axles 39 are inserted and supported by the cover cases 21B.

  Further, the work system power branched by the input shaft 17 is transmitted to the intermediate shaft 42 via the torque limiter 41, and then in the gear chamber 43 formed on the outer side of the case via the gears G1 and G2, the planted transmission shaft. 44, is taken out from the planting transmission shaft 44 to the PTO shaft 46 facing backward through the planting clutch 45, and transmitted to the seedling planting device 6 through the telescopic transmission shaft 47. In addition, the cover 48 of the gear chamber 43 is opened and the gears G1 and G2 are exchanged or exchanged, so that the speed ratio of the working system to the running system is changed and planted in the running direction in the seedling planting device 6. The pitch (between stocks) can be changed and adjusted.

  As shown in FIG. 3, the front axle case 22 is not equipped with a differential mechanism, and the transmitted power is branched to the left and right via a lateral transmission shaft 49 inserted through the front axle case 22. The front wheel 1 is always driven at a constant speed. Further, a multi-plate brake 50 acting on the lateral transmission shaft 49 is provided at the input portion of the front axle case 22. The brake 50 is linked to the stop pedal 19, and when the stop pedal 19 is depressed, the tension mechanism (main clutch) 28 is turned off and the brake 50 is braked. Note that the stop pedal 19 is provided with an operation lever 19a with an extended pedal arm. Even when driving down the ground, the stop pedal 19 is held down by the operation lever 19a to stop traveling. Is possible. Further, a parking lever 48 is provided in the vicinity of the stop pedal 19 for locking and fixing the stop pedal 19 at the operation position.

  As shown in FIGS. 5 and 6, the round pipe material is arched across the left and right ends of the front stay 20 a horizontally connected to the main frame 20 and the mounting seats 51 provided at the left and right rear portions of the transmission case 21. A pair of left and right frame rods 52 bent and fixed are installed and fixed, and the rear portion of the step 8 formed by sheet metal pressing is placed and connected to the upper portion of the frame rod 52.

  The mission case 21 also functions as a member that supports the front end portion of the four-link mechanism 5. That is, the four-link mechanism 5 pivotally connects the front ends of the pair of left and right lower links 5a and the upper links 5b to the transmission case 21, and the rear ends of the lower links 5a and the upper links 5b by the vertical links 5c. It is constructed in a parallel quadruple link structure with pivot support, and by extending and contracting the hydraulic cylinder 4 spanning the connection point d at the front end of the upper link and the rear part of the lower link, the vertical link 5c The connected seedling planting device 6 can be moved up and down in parallel.

  Here, as shown in FIG. 8, a fulcrum shaft 53 is welded and fixed to the front ends of the left and right lower links 5a constituting the quadruple link mechanism 5, and the fulcrum shaft protrudes left and right from the lower link 5a. 53 is fitted and supported from the inside by a fulcrum boss portion 54 protruding from the left and right divided case portions 21Aa and 21Ab constituting the case main body 21A. In the state where the left and right divided case portions 21Aa and 21Ab are joined and connected, the interval between the outer surfaces of the left and right lower links 5a is set slightly smaller than the interval between the inward end surfaces of the left and right fulcrum boss portions 54. The lateral movement of the entire four-link mechanism 5 is restricted by the outer surface of the lower link 5a coming into contact with the inward end surfaces of the left and right fulcrum boss portions 54.

  As shown in FIG. 9, in the step 8 of the sheet metal press structure, the rear part is raised to a height exceeding the engine 7, and a part of the engine 7 and the frame rod 52 are inserted into the left and right central portions of the rear raised part 8a. The opening 56 is formed, and the opening 56 is closed by a cover 57 that is detachably locked. A pair of left and right connecting fittings 58 extending from the frame rod 52 protrude upward through a slit 59 formed in the cover 57, and the driver seat 9 can be turned back and forth on the connecting fitting 58, and Pins are connected so that the front and rear positions can be changed. The driver's seat 9 turned to the seating posture is elastically received and supported by the left and right cushion springs 60 attached to the upper surface of the raised portion 8a. In addition, a reinforcing rib 8b is raised at the center of the floor surface of Step 8, and a group of punches 8c burring upward to prevent slipping when getting on and off is formed on the left and right sides of the floor surface. Yes.

  On the right side of the rear raised portion 8a in step 8, an elevating lever 61 for elevating and lowering the seedling planting device 6 and intermittently powering the seedling planting device 6, a sensitivity adjusting lever 62 for adjusting the sensitivity of the planting depth automatic control, and The lowering lock lever 63 that hydraulically locks and prevents the extension operation of the hydraulic cylinder 4 protrudes, and the accelerator lever 73 protrudes from the right side of the cover 57. Further, a rectangular opening 64 is formed at the rear part of the rear raised portion 8 a in Step 8, and the upper half portion of the fuel tank 65 connected and supported by the frame rod 52 projects upward from the opening 64.

  A recessed portion 8d that is released forward is formed at the left and right central portion at the front end of step 8, and the recessed portion 8d is closed by inserting the center post 10 erected on the front end portion of the traveling machine body 3 up and down. It has become so.

  As shown in FIG. 4, the center post 10 is composed of a highly rigid half-cylindrical main portion 10R formed of a sheet metal material and a front cover portion 10F formed of a resin material. The lower end of 10R is bolted and fixed to a cast-made bracket 81 projecting forward from the front axle case 22, and the front cover portion 10F is detachably locked and connected to the front portion of the main portion 10R. It has become. The bracket 81 has a function as a front weight for balancing the longitudinal weight of the traveling machine body 3, and the front end protruding portion of the bracket 81 is covered from the front by the lower extension portion of the front cover portion 10F. .

  Inside the center post 10, a handle post 82 made of a round pipe standing from a bracket 81 is provided, and an upper end portion of the handle post 82 is connected to a main portion 10 </ b> R of the center post 10. The standing strength is increased. A steering shaft 83 having the steering handle 11 connected to the upper end is inserted and supported by the handle post 82, and the lower portion of the steering shaft 83 is supported by the bracket 81 so as to be integrally formed with the lower end of the steering shaft 83. Is engaged with a large-diameter sect gear 85 pivotally supported below the bracket 81, and, as shown in FIG. 4, a knuckle arm 86 that steers and rotates the sect gear 85 and the left and right front wheels 1; Are linked together by a tie rod 87 to form a steering mechanism 88 for steering the front wheels.

  Further, as shown in FIG. 4, a pair of left and right operation rods 89 extending rearward from the sect gear 85 are linked to the operation shafts 37a of the left and right side clutches 37, respectively, and the sect gear 85 is rotated. When the front wheel 1 is steered from the straight position to the left or right by a set angle (for example, 30 °) or more, the side clutch 37 of the rear wheel 2 on the inside of the turn is automatically turned off in conjunction with this. Thus, a small turn in a three-wheel drive state with the steered left and right front wheels 1 and one rear wheel 2 on the outside of the turn is performed. As shown in FIG. 12, the operation shaft 37 a for engaging and disengaging the left and right side clutches 37 is inserted through the mission case 21 and supported by a common contact plate 115 bolted to the mission case 21 so that it cannot be pulled out. Has been.

  Inside the center post 10, a speed change operation shaft 90 is disposed so as to be rotatable around a vertical axis g along the handle post 82. The upper end portion of the speed change operation shaft 90 is bent to the left side. The formed transmission lever 91 projects from the outer periphery of a lever guide 92 provided at the upper end of the center post 10. The lower end portion of the speed change operation shaft 90 and the speed change operation portion of the speed change mechanism 34 in the transmission case 21 are arranged in the front-rear direction in the lower space of the engine 7 through a push-pull rod 93 as a linkage member as follows. Linked together.

  That is, as shown in FIG. 5, the left side of the transmission case 21 is provided with an intermediate operation shaft 94 that is rotatable around a longitudinal fulcrum h substantially parallel to the axis g of the speed change operation shaft 90. The operation lever 94a fixed to the upper end of the operation shaft 94 is connected to the outer end portion of the shift shaft 40 in the speed change mechanism 34, and the lower end bent portion 94b of the intermediate operation shaft 94 and the lower end portion of the speed change operation shaft 90 are connected. The push-pull rod 93 is installed over the operation arm 90a projecting from the arm 90a. When the speed change lever 91 is turned about the longitudinal axis g to turn the speed change operation shaft 90, the push-pull rod 93 is turned. The intermediate operation shaft 94 is rotated through the shift shaft 40 so that the shift shaft 40 is pushed and pulled left and right. Here, by swinging the shift lever 91 backward from the foremost position, the third forward speed ("moving") used for traveling while not working, and the first forward speed ("畦 越 ”), 2nd forward speed (“ planting ”), neutral (“ N ”), and“ reverse ”used for normal planting travel are obtained sequentially.

  Further, as shown in FIGS. 10 and 11, a check bracket 95 that restricts the operation range of the speed change lever 91 is provided on the upper surface of the lever guide 92. The check metal fitting 95 is formed by bending a round bar into an inverted U shape, and its front end fulcrum shaft 95a is pierced through the lever guide 92 so as to be rotatable and vertically slidable. The check metal fitting 95 is slid downward by a compression coil spring 96 attached to. The check fitting 95 is rotated around the front end fulcrum shaft 95a so that the check producing portion 95b formed by bending the rear end penetrates the hole 97 formed in the lever guide 92 and protrudes greatly below the guide. The checkering portion 95b is supported by a concave portion 98 formed on the upper surface of the lever guide 92, and can be switched to a checker release position where protrusion downward of the guide is prevented. The portion 95 b interferes with the swing operation path of the speed change lever 91, so that the speed change lever 91 can be operated only in the range of “planting” and “reverse”, and the check fitting 95 is opposed to the compression coil spring 96. By lifting and removing the check production part 95b from the hole 97 and moving it to the check release position, the speed change lever 91 can be operated in the entire region from “movement” to “reverse”.

  It should be noted that the spring receiving beta pin 99 penetratingly attached to the front end fulcrum shaft 95a of the check fitting 95 is inserted into the front end fulcrum shaft 95a from the direction along the longitudinal direction of the check fitting 95, and is received by the beta pin 99. The compression coil spring 96 is stably held in a posture orthogonal to the check fitting 95, and the check fitting 95 is appropriately slid downward.

  In addition, as shown in FIG. 2, the lever guide 92 is fixed so that the front edge m of the lever guide 92 coincides with the fuselage center line x, and the seated driver sets the front edge m of the lever guide 92 as a center aim. It is configured to be available.

  16 and 17 show the operation structure of the control valve 15. The control valve 15 incorporates a flow path switching spool 101 so as to be slidable back and forth, and its front end protrudes from the casing 15a. This spool 101 is sequentially switched to “down”, “neutral”, and “up” as it is pushed backward from the forward projecting position, and the front “down” position is slid toward the side by an internal spring. It is energized. An automatic operation arm 102 for operating the spool 101 based on the vertical swing displacement of the leveling float 14 and a manual operation arm 103 for manually operating the spool 101 at the front of the casing 15a of the control valve 15 Is deployed. A lateral fulcrum boss 104 is integrally formed at the lower portion of the front end of the casing 15a. The automatic operation arm 102 is rotatably fitted and supported on a fulcrum shaft 105 inserted through the fulcrum boss 104. The manual operation arm 103 is fixed to the shaft 105 by welding.

  The automatic operation arm 102 is provided with a lateral operation pin 102 a that comes into contact with the tip of the spool 101, and the tip of the inner front portion 106 i of the sensor wire 106 extended from the seedling planting device 6 is the automatic operation arm 102. It is connected to the upper end. The sensor wire 106 is connected and supported at the front end of the outer wire 106o to the lower end of the sensitivity adjustment lever 62. When the leveling float 14 is swung upward from the reference position, the inner front portion 106i is pulled backward. In addition, when the leveling float 14 is swung downward from the reference position, the inner front portion 106i is loosened.

  Therefore, when the seedling planting device 6 is at a predetermined height with respect to the paddy field, the leveling float 14 is in the reference position, and at this time, the spool 101 that is projected and biased forward is applied to the operation pin 102a of the automatic operation arm 102. It is supported and held in “neutral” N. When the traveling machine body 3 sinks due to the unevenness of the cultivator or descends downward, the seedling planting device 6 starts to sink with respect to the paddy surface, the ground pressure of the leveling float 14 increases, and the leveling float 14 swings upward from the reference position. The inner front portion 106i of the sensor wire 106 is pulled rearward, and the spool 101 is pushed to the rear “rising” U side through the operation pin 102a by the swinging of the automatic operation arm 102 to the rear side. When the cylinder 4 is shortened by pressure oil supply and the seedling planting device 6 is raised, and the leveling float 14 returns to the original reference position, the raising operation is stopped. Further, when the traveling machine body 3 is lifted or raised by the unevenness of the tiller, the seedling planting device 6 floats on the paddy surface, and the ground pressure of the leveling float 14 decreases, and the leveling float 14 moves downward from the reference position. The inner front part 106i of the sensor wire 106 is loosened by swinging and the automatic operation arm 102 is allowed to swing forward, so that the spool 101 is displaced forwardly to the “down” D side by the biasing force. Then, when the hydraulic cylinder 4 is extended by draining and the seedling planting device 6 is lowered by its own weight, and the leveling float 14 returns to the original reference position, the lowering operation is stopped. Thus, by stably maintaining the posture of the leveling float 14 at the reference position, the height of the seedling planting device 6 relative to the rice field can be maintained within a certain range, and the planting depth can be stabilized.

  In addition, when the movement adjusting lever 62 is adjusted to swing, the front end of the outer wire 106o in the sensor wire 106 is adjusted in the front-rear direction, whereby the leveling float 14 when the control valve 15 is "neutral" is adjusted. The reference position is changed. In other words, the front end fixing position of the outer wire 106o is changed to the rear as the impression adjusting lever 62 is operated forward, whereby the reference position of the leveling float 14 is changed to the front lowering direction. A state of being easily displaced upward is brought about, and the control sensitivity becomes sensitive. On the other hand, the front end fixing position of the outer wire 106o is changed to the front as the impression adjusting lever 62 is operated rearward. As a result, the reference position of the leveling float 14 is changed to the front rising direction, and the ground leveling is not increased unless the ground pressure increases greatly. A state is brought about in which the float 14 is not displaced upward, and the control sensitivity becomes insensitive. Therefore, when the surface is soft, the sensitivity adjustment lever 62 is operated forward to make the control sensitivity sensitive. When the surface is hard, the sensitivity adjustment lever 62 is operated backward to make the control sensitivity insensitive. To do.

  The fulcrum shaft 105 is formed by bending the base of the elevating lever 61. By swinging the elevating lever 61 back and forth, the manual operation arm 103 is swung in the same direction as the lever operating direction. Thus, the operation pin 102a of the automatic operation arm 102 is contacted from the front. Here, a detent plate 108 having four recesses 107 formed on the outer periphery thereof is integrally connected to the manual operation arm 103 and is pivotally supported by the right side surface of the mission case 21 and is oscillated and biased by a spring 109. The lifting lever 61 is switched between the four operation positions “planting”, “lowering”, “neutral”, and “raising” by elastically engaging the detent roller 111 at the tip of the arm 110 into one of the recesses 107. Can be done.

  When the lifting lever 61 is in the illustrated “neutral” position, the manual operation arm 103 holds the spool 101 in the “neutral” position via the operation pin 102a, and the seedling planting device 6 has an arbitrary height. Retained.

  When the elevating lever 61 is switched to the “up” position, the manual operation arm 103 moves the spool 101 to “up” via the operation pin 102a, and the seedling planting device 6 is driven up. In addition, when the seedling planting device 6 raised by the operation of the lifting lever 61 reaches a predetermined upper limit position, the lifting lever 61 is automatically returned to “neutral” to stop the lifting. That is, the check arm 112 is erected from the base of the upper link 5 b of the four-link mechanism 5, and the check rod 113 extending forward from the tip of the check arm 112 is inserted into the upper part of the automatic operation arm 102. When the upper link 5b is swung up to a predetermined height, the stopper pin 114 attached to the check rod 113 pushes the automatic operation arm 102 in the “up” position forward, and the automatic operation arm 102 is connected to the automatic operation arm 102 via the operation pin 102a. Thus, the manual operation arm 103 and the lifting lever 61 which are in contact with the front are moved to “neutral”.

  When the elevating lever 61 is switched to the “down” position, the manual operation arm 103 is in a position away from the operating range of the operation pin 102a, and the automatic operation arm 102 is displaced in the vertical swinging position of the leveling float 14 as described above. If the lifting / lowering lever 61 is operated to the “down” position while the seedling planting device 6 is lifted and raised from the rice field, the automatic planting device 6 swings on the basis of the swinging operation until the seedling planting device 6 contacts the rice field. Will be lowered.

  When the elevating lever 61 is switched to the “planting” position, the manual operation arm 103 moves to a position far away from the operating range of the operation pin 102a and enters the automatic elevating control state.

  Here, only when the elevating lever 61 is in the “planting” position, the planting clutch 45 is engaged and operated, so that seedling can be planted. The elevating lever 61 can be “down”, “neutral”, or “up”. The planting clutch 45 is turned off even if it is operated to the position.

  That is, as shown in FIGS. 6, 7, and 16, a clutch operating shaft 116 for operating the planting clutch 45 is slidably mounted on the right side surface of the mission case 21, and the clutch operating shaft 116 is moved in and out. A bell crank-shaped clutch operating lever 117 to be operated is provided so as to be rotatable around a longitudinal fulcrum i. The front end of the operating rod 118 extending forward from one end of the clutch operating lever 117 is connected to the lift lever 61. Is inserted into the slit 119 formed in the detent plate 108 that swings integrally with the rear part.

  The planting clutch 45 is energized and is in a clutch engaged state when the clutch operating shaft 116 is pulled out, and is a known constant clutch operated at a predetermined rotational phase when the clutch operating shaft 116 is inrushed. A position stop structure is employed, and the clutch operating lever 117 is urged to rotate in the clutch disengagement direction by a torsion spring 120 provided at a fulcrum. Therefore, when the elevating lever 61 is in the “down”, “neutral”, and “up” positions, the tip of the operating rod 118 is within the slit 119, and the clutch operating shaft 116 is moved by the clutch operating lever 117. Although the rush operation is performed at the clutch disengagement position, when the lifting lever 61 is operated to the “planting” position, the front end of the slit 119 presses the front end of the operation rod 118 backward as the detent plate 108 rotates backward. As a result, the clutch operation lever 117 is rotated in the clutch engagement direction against the rotation urging force, and the clutch operation shaft 116 is extracted and the planting clutch 45 is engaged.

  As shown in FIGS. 17 to 19, the lowering lock lever 63 is connected to a vertical operating shaft 121 protruding from the upper surface of the control valve 15, and allows the hydraulic cylinder 4 to expand and contract by opening the oil passage. The “open” position for closing the oil passage and the “closed” position for hydraulically locking the extension operation (downward) of the hydraulic cylinder 4 by closing the oil passage are configured to be rotatable. The lever base is provided with a detent structure for switching and holding.

  That is, a detent member 122 formed by bending a spring wire is fixed to the operation shaft 121 together with the lowering lock lever 63, and a cantilever arm portion 122a formed on the detent member 122 projects from the upper surface of the valve. It is applied to the outer periphery of the boss portion 123. Two flat cam surfaces S1 and S2 are formed at a predetermined angle on the outer periphery of the boss portion 123, and the cantilever arm portion 122a of the detent member 122 is received and supported by either of the cam surfaces S1 and S2. As a result, the lowering lock lever 63 is stably held in the “open” position or the “closed” position, and when the lowering lock lever 63 is rotated, the cantilevered arm portion 122a elastically moves the top where the two cam surfaces S1, S2 intersect. It passes through while deforming, and it works to exceed the dead point.

[Other Examples]
(1) As the transmission mechanism 34, in addition to the gear type incorporated in the transmission case 21 as described above, a hydraulic continuously variable transmission mounted on the side surface of the transmission case 21, or the engine 7 and the transmission case 21. Any transmission mechanism such as a belt-type continuously variable transmission equipped in a winding transmission system can be used.

  (2) As the linkage member 93 for interlockingly connecting the speed change operation shaft 90 and the speed change mechanism 34, a release wire can be used in addition to the push-pull rod as described above.

Overall side view of riding rice transplanter Overall plan view of the riding rice transplanter Plan view of traveling system Vertical side view of the steering control section Left side view of the rear of the aircraft Right side view of the rear of the aircraft Plan view of the rear of the aircraft Rear view of the rear of the aircraft Exploded perspective view of steps Top view of the shift lever operation section Longitudinal side view showing shift check structure Vertical rear view of transmission case Transverse plan view showing part of the transmission case Transverse plan view showing part of the transmission case Cross-sectional plan view of pump drive Side view of control valve operation structure Exploded perspective view of control valve operation structure Front view of the lowering lock lever Plan view explaining the detent operation of the lowering lock lever

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front wheel 2 Rear wheel 6 Working device 7 Engine 21 Mission case 22 Front axle case 34 Transmission mechanism 88 Steering mechanism 90 Transmission operation shaft 91 Transmission lever 93 Linking member (push-pull rod)
g Vertical axis

Claims (4)

The engine is arranged behind the front axle case equipped with the front wheels that can be steered, the transmission case equipped with the rear wheels that cannot be steered is linked to the engine, and the driving power extracted from the mission case is In the agricultural work machine configured to transmit to the front axle case and connected to the rear part of the machine body so as to be able to drive up and down,
A speed change lever for operating a speed change mechanism provided in the transmission case is supported so as to be swingable around a vertical axis through a speed change operation shaft arranged vertically in the vicinity of the steering handle. A shift operation structure for an agricultural machine, wherein a lower end portion and a shift operation portion of the transmission mechanism are interlocked and connected by a linkage member provided through a space below the engine.   The shift operation structure for an agricultural machine according to claim 1, wherein the linking member is disposed above the front axle case.   The shift operation structure of the agricultural machine according to claim 1 or 2, wherein the linking member is disposed above a steering mechanism that steers the front wheel.   The shift operation structure for an agricultural machine according to any one of claims 1 to 3, wherein the linking member is constituted by a push-pull rod.

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