JP2006082716A - Speed change operation structure of working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a speed change operation structure of a working machine capable of enhancing the operating easiness by performing the speed change operation and the accelerating operation simultaneously, and nevertheless capable of conducting a low speed running with any engine output. <P>SOLUTION: The speed change operation structure of the working machine includes a speed change tool 53 which manipulates a speed change device for running and is arranged interlocking with a speed governing mechanism 95 of an engine 12, wherein the speed governing mechanism 95 is operated in the direction to the higher speed side in association with the speed change tool 53 being operated in the speed increasing direction from the neutral N, and further a manual operation tool 31 is installed to operate the speed governing mechanism 95 any as desired. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a speed change operation structure used in agricultural work machines such as rice transplanters and combines.

As the above speed change operation structure, the speed change operation tool for operating the speed change transmission and the speed control mechanism of the engine are linked, and the speed control mechanism is operated as the speed change operation tool is operated from the neutral to the speed increasing direction. An apparatus configured to operate in a high speed direction has been proposed (see, for example, Patent Document 1).
JP 2003-104082 A

  According to the above speed change operation structure, when the speed change operation tool is operated to the neutral position, a predetermined idling state is established, and the engine speed is increased as the travel speed is increased by operating the speed change operation tool in the speed increasing direction. The operability can be improved by simultaneously performing the shifting operation and the accelerator operation, and it is also effective in improving the fuel consumption, but the idling rotation speed when the shifting operation tool is operated to the neutral position Therefore, when working while driving at a low speed by slightly operating the speed change operation tool from the neutral position, the engine speed is slightly higher than the idling speed and the engine is operated at a low engine output. In other words, depending on the working conditions, there is a possibility that the engine stop may occur due to an increase in work load or travel load.

  The present invention has been made paying attention to such points, and is capable of improving the operability by simultaneously performing the shift operation and the accelerator operation, while being driven at a low speed with an arbitrary engine output. The main purpose is to be able to do the same.

A first aspect of the present invention is to link a speed change operating tool for operating a speed change gear and a speed control mechanism of an engine so that the speed control mechanism is operated at a higher speed as the speed change operating tool is operated from a neutral direction to a speed increasing direction. A shift operation structure for a work machine configured to operate in a direction,
An artificial operation tool for arbitrarily operating the speed control mechanism is provided.

  According to the above configuration, when the speed change operation tool is operated to the neutral position, the engine enters a predetermined low speed state, and the engine speed is increased as the travel speed is increased by operating the speed change operation tool in the speed increasing direction. The output is increased. In addition, by operating the manipulating tool to arbitrarily operate the speed adjusting mechanism, it is possible to increase the engine output appropriately and increase the engine output even when the speed change operation is operated at a low speed.

  Therefore, according to the first aspect of the invention, the operability can be improved by simultaneously performing the speed change operation and the accelerator operation, and at the same time, the vehicle can be driven at a low speed at a high engine output state, and can perform a wide range of work and It can cope with traveling suitably.

According to a second invention, in the first invention,
The artificial operation tool changes and adjusts the operation position of the speed control mechanism when the speed change operation tool is neutral.

  According to the above configuration, it is possible to easily start the engine by slightly accelerating when the shifting operation tool is in the neutral position and stopped running.

According to a third invention, in the first or second invention,
The torque characteristic of the speed governing mechanism is set so that the torque efficiency of the engine is maximized when the artificial operating tool is at the operation limit position on the high speed side.

  According to the above configuration, by operating the human operation tool to the operation limit position on the high speed side, the engine output can be efficiently used to perform high load work or high load traveling.

A fourth invention is the invention according to any one of the first to third inventions,
The engine rotation speed when the shift operation tool is operated to the maximum speed position is set higher than the engine rotation speed when the artificial operation tool is operated to the operation limit position on the high speed side.

  According to the above configuration, the engine can be operated at a higher speed with the speed change operation tool even when the human operation tool is operated to the operation limit position on the high speed side. It is possible to ensure work and travel with excellent mobility.

A fifth invention is the invention according to any one of the first to fourth inventions,
The shift operation tool is configured to be operable over a forward range and a reverse range, and is configured to operate the speed control mechanism by displacing a common linkage member by an operation in the forward range and a reverse range. Is.

  According to the above configuration, the speed control mechanism can be operated through a common linkage member regardless of forward shift and reverse shift, compared to a structure using two types of linkage members, a forward operation system and a reverse operation system. The linking member can be saved, which is effective in simplifying the structure and reducing the cost.

In a sixth aspect based on the fifth aspect,
A forward operation member that is displaced by an operation of the shift operation tool toward the forward region; and a reverse operation member that is displaced by an operation of the reverse region; the forward operation member is connected to the speed control mechanism; And the forward-side operation member is operated by one-side operation by the backward-side operation member.

  According to the above configuration, the linkage member may be connected only to the forward operation member, and the forward operation member may be operated by one-side operation by the reverse operation member, and the fifth invention can be suitably implemented. .

    1 and 2 show a riding type rice transplanter as an example of a working machine. This riding type rice transplanter has a six-row planting seedling at the rear of a riding type traveling machine body 3 having a pair of left and right front wheels 1 that can be steered and a pair of rear wheels 2 that cannot be steered. The planting device 4 is connected to be movable up and down through a parallel quadruple link mechanism 6 driven by a hydraulic cylinder 5, and has a structure in which a fertilizer device 7 is provided at the rear of the machine body.

  A transmission case 9 that pivotally supports the front wheel 1 is connected and fixed to the front part of the body frame 8 in the traveling body 3, and a rear transmission case 10 that pivotally supports the rear wheel 2 is disposed at the rear part of the body frame 8. It is supported so that it can roll freely. An engine 12 is mounted horizontally on a front frame 11 extending forward from the mission case 9 and covered with a bonnet 13, and the front wheel 1 is operated on a boarding operation part located behind the engine 12. A steering handle 14, a driver's seat 15, a step 16 and the like are provided for the direction operation, and a left and right front part of the fuselage is provided with spare seedling stands 17 for placing and accommodating spare seedlings in a plurality of stages. Yes.

  The seedling planting device 4 mounts seedlings for six lines, and seedling seedlings 21 that are reciprocated by a set stroke in the left-right direction, cut out seedlings one by one from the lower ends of the seedling mounting bases 21, and plant them on the field. It consists of six sets of rotary planting mechanisms 22 and three leveling floats 23 that level the planting location. Further, the fertilizer application device 7 is mounted on the traveling machine body 3 between the driver seat 15 and the seedling planting device 4, and a fertilizer hopper 24 for storing powdered fertilizer and a fertilizer in the fertilizer hopper 24 are set. A feeding mechanism 25 that feeds out the amount by volume, an electric blower 28 that winds the fed fertilizer to a groove forming device 27 provided in each leveling float 23 via a supply hose 26, and the like. It is configured to send fertilizers into the grooves formed in and embed.

  14 and 15 schematically show the transmission structure of this rice transplanter. The side surface of the transmission case 9 is connected to a hydrostatic continuously variable transmission (HST) 41 as a main transmission that is belt-linked to the engine 12, and the output is input to the transmission case 9 for work. Branches into a system and a traveling system.

  As for the power of the branched work system, only the forward rotation power is taken out by the one-way clutch 42, and the working power take-out shaft (PTO shaft) is passed through the stock transmission mechanism 43 and the planting clutch 40 capable of six-speed gear shifting. 45, and is transmitted to the seedling planting device 4 through the transmission shaft 46.

  The branched traveling system power is shifted to a high and low two-stage by a gear-type auxiliary transmission mechanism 47 and then branched again to the front wheel system and the rear wheel system, and the power of the front wheel system passes through a differential device 48 that can be differentially locked. While being transmitted to the left and right front wheels 1, the power of the rear wheel system is transmitted to the rear transmission case 10 via the transmission shaft 49, and is transmitted to the left and right rear wheels 2 via the multi-plate type side clutch 50. The rear transmission case 10 is equipped with a multi-plate brake 51 for stopping the airframe, and this brake 51 is mechanically linked to a single pedal 52 for stopping driving provided at the right foot of the step 16. Has been.

  Here, the continuously variable transmission 41 is shifted by a main transmission lever (transmission operation tool) 53 provided on the left side of the steering handle 14, and the auxiliary transmission mechanism 47 is arranged on the left side of the driver seat 15. The sub-transmission lever 54 provided in FIG. The differential device 48 of the front wheel 1 is differentially locked by depressing a differential lock pedal 55 at the foot, and the left and right front wheels 1 are driven at a constant speed.

  Although the detailed structure is not illustrated, the left and right side clutches 50 are automatically operated in conjunction with the steering of the front wheels 1, and the steering wheel 14 sets the front wheels 1 to the left or right to a set angle (for example, 30 °). ) When steered as described above, the side clutch 50 of the rear wheel 2 that is on the inside of the turn is automatically turned off, and a smooth and small turn is performed.

  Next, the shift operation structure of the transmission 41 will be described.

  As shown in FIGS. 7 and 9, a support bracket 62 is fixed to the handle post 61 that supports the steering handle 14, and a detent plate 64 is laterally supported at a left end portion of the support bracket 62 via a support shaft 63. The main transmission lever 53 is supported by the detent plate 64 so as to be able to swing left and right around the fulcrum b in the front-rear direction. A relay rotation member 66 is supported on a support frame 65 that supports the handle post 61 so as to be rotatable about a lateral fulcrum c. The relay rotation member 66 and the detent plate 64 are linked via a linkage rod 67. Further, the relay rotating member 66 and the speed change arm 69 connected to the speed change operation shaft 68 of the continuously variable transmission 41 are linked via a linkage rod 70.

  As shown in FIGS. 9 and 11, a guide plate 71 is fixed to the support bracket 62, and a stepped guide groove 72 formed in the guide plate 71 extends downward from the base of the main transmission lever 53. The detent plate is formed by penetrating the guide rod 53a that has been taken out and swinging the main speed change lever 53 back and forth along a predetermined stepwise operation path by engaging and guiding the guide groove 72 and the guide rod 53a. The continuously variable transmission 41 can be shifted in a range from the forward range to the reverse range by rotating 64 in the forward and reverse directions.

  As shown in FIG. 12, the stepped portion of the stepped operation path corresponds to the neutral position N of the continuously variable transmission 41, and the forward shift operation path F is formed in front of it and the reverse change operation path R is formed in the rear. At the same time, the detent roller 74 supported on the free end of the cantilever spring lever 73 is elastically engaged with nine recesses 64a formed in parallel on the outer periphery of the detent plate 64, thereby moving the main transmission lever 53 forward five steps (F1 to F1). F5), the neutral position N, and the three shift positions (R1 to R3) can be held at the respective shift positions.

  As shown in FIG. 8, the speed change operating shaft 68 of the continuously variable transmission 41 is composed of a V-shaped cam 69a connected to the speed change arm 69 and a positioning roller 76 pressed against the V-shaped cam 69a by a spring 75. The neutral positioning mechanism 77 is mechanically stably held at the neutral position N.

  When the main shift lever 53 is operated in the forward travel state in which the forward shift operation path F is operated, or in the reverse travel state in which the main shift lever 53 is operated in the reverse shift operation path R, the main shift lever 53 is depressed. 53 is forcibly returned to the neutral position N, and its structure is shown in FIGS.

  That is, a check operating member 81 is provided behind the transmission operation unit so as to be swingable back and forth around the fulcrum e. This check operating member 81 is provided with a check fitting 81a whose position can be finely adjusted around a fulcrum f by an adjusting bolt 81b, and the front edge portion of the check operation member 81 is above the fulcrum c of the relay rotating member 66. The second contact pin 83 is configured to face the first contact pin 82 provided at a location from the rear, and the front edge of the check fitting 81 a is provided at a location below the fulcrum c of the relay rotation member 66. It is deployed to face the rear from the back.

  On the other hand, a check operation arm 85 is fixed to the other end portion of the pedal support shaft 84 to which the pedal 52 is connected, and the check operation is performed on a boss member 86 pivotally supported on the free end of the check operation arm 85. A rear end portion of the push-pull rod 87 extending rearward from the lower end of the member 81 is inserted and connected. Here, the push-pull rod 87 is inserted and supported so as to be slidable back and forth only within a certain range with respect to the boss member 86 and is pushed by a compression coil spring 88 that is preliminarily initially compressed and externally fitted to the push-pull rod 87. The pull rod 87 is slid to the front slide limit with respect to the boss member 86.

  3 shows a state in which the pedal 52 is not depressed and the main transmission lever 53 is in the neutral position N. FIG. 4 is a fifth forward speed in which the pedal 52 is not depressed and the main transmission lever 53 is the maximum forward speed. FIG. 5 shows a state in which the main shift lever 53 is in the reverse third speed R3 which is the highest reverse speed without the pedal 52 being depressed.

  According to this, when the pedal 52 is depressed when the main speed change lever 53 is in the forward speed change operation path F (for example, the state shown in FIG. 4), the check operation arm 85 is turned in the counterclockwise direction in FIG. The pulling rod 87 is projected forward (leftward in the figure), and the check operating member 81 is swung clockwise around the fulcrum e. As a result, the check operation member 81 presses and presses the first contact pin 82 forward, the relay rotation member 66 is forcibly rotated counterclockwise around the fulcrum c, and the main transmission lever 53 is moved to the neutral position N side. It will be turned back.

  Then, when the main transmission lever 53 reaches the neutral position N, as shown in FIG. 6, the second contact pin 83 is also in contact with the check fitting 81a, and the first position located on both the upper and lower sides of the fulcrum c. When the contact pin 82 and the second contact pin 83 are both in contact with the check operation member 81, the relay rotation member 66 is held in a fixed posture in which the main transmission lever 53 is in the neutral position N. In addition, the check operation member 81 itself that is in contact with the first contact pin 82 and the second contact pin 83 cannot be rotated further clockwise. In addition, by adjusting the position of the check fitting 81a of the check operation member 81, the first contact pin 82 and the second contact pin 83 are brought into contact with the check operation member 81 so that the relay turning member 66 is accurately neutralized. Can be restored.

  Here, the initial compression force applied by the compression coil spring 88 is set to be larger than the operating force required for forcibly moving the main transmission lever 53, and until the main transmission lever 53 reaches the neutral position N, The compression coil spring 88 is not compressed and deformed by an operation reaction force. When the pedal 52 is further depressed after the main transmission lever 53 reaches the neutral position N, the check operation arm 85 further moves the compression coil spring 88 against the push-pull rod 87 that has become unable to move forward. A sufficient brake operation stroke is ensured by rotating counterclockwise in the figure while being compressed and deformed.

  Further, when the pedal 52 is depressed when the main speed change lever 53 is in the reverse speed change operation path R (for example, the state shown in FIG. 5), the check operating arm 85 is rotated counterclockwise in the drawing, thereby pushing and pulling the rod. 87 is protruded forward (leftward in the figure), and the check operation member 81 is swung clockwise around the fulcrum e. As a result, the check fitting 81a of the check operation member 81 contacts and presses the second contact pin 83 forward, the relay turning portion 66 is forcibly turned clockwise around the fulcrum c, and the main transmission lever 53 is in the neutral position. It is returned toward the N side. When the main transmission lever 53 reaches the neutral position N, as shown in FIG. 6, the first contact pin 82 also comes into contact with the check fitting 81 a of the check braking member 81, and both the upper and lower sides of the fulcrum c The first contact pin 81 and the second contact pin 83 located in the contact with the check operation member 81 hold the relay rotation member 66 in a fixed posture in which the main transmission lever 53 is in the neutral position N. Is done.

  Also in this case, the compression coil spring 88 is not compressed and deformed by the operation reaction force until the main transmission lever 53 reaches the neutral position N. After the main transmission lever 53 reaches the neutral position N, the pedal is further pedaled. By depressing 52, the restraining operation arm 85 is rotated counterclockwise in the figure while further compressing and deforming the compression coil spring 88 with respect to the push-pull rod 87 which has become unable to move forward.

  When the pedal 52 is depressed to forcibly return the main transmission lever 53 toward the neutral position N, if the depression is stopped before reaching the neutral position N, the main transmission lever 53 can be depressed. It will decelerate to the shifting position according to the position and will be held at that position, so you can reduce the traveling speed with just foot operation while using both hands for handle operation and other operations, It is effective to improve operability.

  Further, when the continuously variable transmission 41 is operated by the main transmission lever 53, the rotational speed of the engine 12 is changed in conjunction with the operation, and the structure will be described with reference to FIGS. explain.

  As shown in FIG. 10, on the upper surface of the guide plate 71 provided with the guide groove 62 for guiding the guide rod 53 a of the main transmission lever 53, the forward operation member 91 is a fulcrum g so as to overlap the forward transmission operation path F. The reverse operation member 92 is pivotally connected so as to be swingable around the fulcrum h so as to overlap the reverse change operation path R. An inner wire rear portion 93ir of an operation wire (linkage member) 93 is connected to the rear end portion of the forward operation member 91, and the rear end of the outer wire 93o is supported by a position-fixed wire catch 94. The front end of the outer wire 93o in the operation wire 83 is connected to the wire receiving portion 96a connected to the speed adjusting lever 96 of the mechanical speed adjusting mechanism (mechanical governor) 95 provided in the engine 12, and the wire receiving The end portion of the inner wire front portion 93if drawn out from the portion 96a is connected and supported by a fixed-position wire receiver 98. Further, a return spring 99 that swings and urges the forward operation member 91 in a direction in which the inner wire rear portion 93ir is pulled back to the outer wire side is connected to the rear end portion of the forward operation member 91, and The swing limit in the urging direction is restricted by the stopper 100 on the guide plate 71.

  On the other hand, the reverse operation member 92 extends beyond the fulcrum h to the rear, and an engagement piece 92a bent and erected at the rear end portion is provided at the rear end portion of the forward operation member 91 in the biasing swinging direction. Is engaged from. Further, the return swing limit of the reverse operation member 92 is regulated by the stopper 101 on the guide plate 61.

  The speed control lever 96 of the speed control mechanism 95 is oscillated and biased to the “low speed” side by the return spring 102. When the inner wire front portion 93if of the operation wire 93 is loosened, the speed control lever 96 is moved to the “low speed” side. When the inner wire front portion 93if that is biased and swung is pulled into the outer wire 93o, the speed control lever 96 that supports the front end of the outer wire 93o is relatively "high-speed" against the return spring 102. As shown in FIG. 10, when the main transmission lever 53 is in the forward side neutral position Nf, the speed adjusting mechanism 95 is maintained at a predetermined low speed position.

  Then, as shown in FIG. 11 (a), when the main transmission lever 53 is operated to the forward transmission operation path F beyond the forward neutral position Nf, the forward operation member 91 resists the return spring 99. The inner wire rear portion 93ir of the operation wire 93 is pulled out in the middle clockwise direction, whereby the inner wire front portion 93if is pulled into the outer wire 93o, and the speed control lever 96 is displaced to the “high speed” side to rotate the engine. Speed is increased. Further, as shown in FIG. 11B, when the main speed change lever 53 is operated from the forward side neutral position Nf to the reverse side neutral position Nf or the reverse speed change operation path R, the reverse side operation member 92 is moved around the fulcrum h. The forward operation member 91 swung in the clockwise direction in the drawing and connected to the reverse operation member 92 through the engagement piece 92a is swung in the clockwise direction in the drawing against the return spring 99. As a result, the inner wire rear portion 93ir is pulled out, and the speed control lever 96 of the speed control mechanism 95 is displaced to the “high speed” side as described above to increase the engine speed.

  Note that the main transmission lever 53 is urged laterally around the fulcrum b by the torsion spring 90. In a free state where the main transmission lever 53 is left in the neutral N position, as shown in FIG. In this state, the speed adjusting mechanism 95 is maintained at a predetermined low rotational speed (idling rotational speed). Therefore, as described above, the main transmission lever 53 is brought into the accelerator-up state only by moving from the forward side neutral Nf to the reverse side neutral Nr. The relationship between the change operation position of the main transmission lever 53 and the engine speed is determined by the side shapes of the forward operation member 91 and the reverse operation member 92, and an example thereof is shown in FIG. .

  Further, when the main shift lever 53 is operated to the reverse change operation path R including the reverse side neutral Nr and the reverse side operation member 92 is swung, this is detected by the switch 103 attached to the guide plate 71. It has become. The reverse detection switch 103 is an activation switch that executes control (referred to as backup control) for automatically raising the seedling planting device 4 to the upper limit.

  This backup control is introduced in order to automatically forcibly raise the seedling planting device 4 at the rear of the machine when the machine is moved backward in the field to avoid colliding with a cocoon or the like. Ascending control is desired. Here, as described above, since the engine rotation speed is increased from the time when the main transmission lever 53 is operated to the reverse side neutral Nr, the discharge amount of the hydraulic pump driven by the output of the engine 12 is increased and the speed is increased. Ascent control can be executed.

  As described above, the speed adjusting mechanism 95 operated in conjunction with the speed change operation of the main speed change lever 53 can be artificially adjusted, and the structure thereof will be described below.

  As shown in FIG. 10, on the right side of the steering handle 14, a hand accelerator lever (an example of a human operation tool) 31 that can swing back and forth and can hold friction at an arbitrary operation position is provided. An inner wire rear portion 32ir of the second operation wire 32 of the hand accelerator lever 31 is connected, and a rear end of the outer wire 32o is connected and supported by a fixed-position wire receiving bracket 33. The front end of the outer wire 32o of the second operation wire 32 is connected to and supported by the wire receiving portion 96a of the speed control lever 86, and the inner wire front portion 32if led out from the front end of the outer wire 32o is connected to the front of the inner wire of the operation wire 93. It is connected and supported by a wire bracket 98 that supports and supports the portion 93if.

  According to the above configuration, when the main transmission lever 53 is in the forward neutral position Nf in a state where the hand accelerator lever 31 is operated to the lower limit position, the two inner wire front portions 93if connected to the wire bracket 98 are provided. , 32if are in a state where there is no slack, the speed control lever 96 of the speed control mechanism 95 is at the lowest speed position, and the engine 12 operates at a predetermined idling rotational speed.

  Here, if the hand accelerator lever 31 is operated to an arbitrary position on the high speed side while the main transmission lever 53 is positioned at the forward side neutral Nf and frictionally held, the inner wire rear portion of the second operation wire 32 according to the operation amount. As a result, the inner wire front 32if is pulled in, and the speed adjusting lever 96 is operated to the “high speed” side against the return spring 102, and is adjusted at a position corresponding to the holding position of the hand accelerator lever 31. The speed lever 96 is also held. Thus, the minimum rotational speed of the engine 12 when the main transmission lever 53 is in the forward side neutral Nf can be held arbitrarily higher than the idling rotational speed.

  Therefore, when it is difficult to start the engine in cold weather or in cold regions, the hand accelerator lever 31 is operated slightly faster to bring the accelerator up while the main transmission lever 53 is positioned at the forward neutral position Nf. Thus, the engine can be reliably started.

  Further, when the second operation wire 32 is pulled by the hand accelerator lever 31 and the accelerator is raised as described above, the inner wire front portion 93if of the other operation wire 93 is in a slack state, and the main transmission lever 53 is moved forward. Until the inner wire front portion 93if of the operation wire 93 is in a tension state by operating in the speed change range F or the reverse speed change range R, the state in which the speed control lever 96 is operated and held by the second operation wire 32 continues. Only when the lever 53 is operated to the high speed side, the accelerator up operation described above is performed via the operation wire 93.

  When the hand accelerator lever 31 is operated to the operation limit position on the high speed side, the speed control lever 96 is not yet operated to the maximum speed setting position. In this state, the main transmission lever 53 is operated to the acceleration side. When operating to the limit position, the speed control lever 96 is further operated to the high speed side. That is, the engine rotation speed when the main transmission lever 53 is operated to the highest forward speed is higher than the engine rotation speed when the main transmission lever 53 is neutral N and the hand accelerator lever 31 is operated to the highest speed position. It has become. The torque characteristic of the speed governing mechanism 95 is set so that the torque efficiency of the engine 12 is maximized when the hand accelerator lever 31 is operated to the operation limit position on the high speed side.

[Another embodiment]
The speed change operation structure according to the present invention can also be implemented in the following form.

  (1) As shown in FIGS. 16 and 17, the reverse operation member 92 is engaged with the pin 91 a that connects the inner wire end fitting 93ie of the operation wire 93 to the advance operation member 91, so that the reverse operation member 92 is engaged. The forward-side operation member 91 can also be contacted by swinging 92.

  (2) In addition to using a hydrostatic continuously variable transmission (HST) as the traveling transmission 41, a gear-type multi-stage transmission, a belt-type continuously variable transmission and a forward / reverse switching mechanism are combined. Or a continuously variable transmission using a planetary gear can be used alone or in combination.

  (3) As a shift operation tool for operating the continuously variable transmission 41, a pedal may be used in addition to the lever.

  (4) As the speed control mechanism 95 of the engine 12, an electronic governor can be used in addition to the mechanical one. In this case, the operation position of the speed change operation tool and the operation of the manipulator for operating the accelerator are used. It is also possible to electrically detect the position with a potentiometer or the like, and to control the electronic governor with characteristics preset for the operation position. In the case of such an electric control type, the human-operated operation tool for operating the accelerator can be selected from various specifications such as a slide knob type and a rotary dial type as well as a lever type.

  (5) In the embodiment, the shape of the reverse operation member 92 is set so that the accelerator is raised when the main shift lever (transmission operation tool) 53 is operated to the reverse neutral Nr. It is also possible to carry out by setting the shape of the reverse operation member 82 so that the accelerator up operation is performed when the reverse shift range R is operated beyond the reverse neutral Nr without accelerator up.

  (6) As a linking member that links the forward operation member 91 and the speed control lever 96, a link mechanism combining rods and links can be used in addition to using the operation wire 93 as described above.

  (7) The outer peripheral shape of the detent plate 64 is formed as shown in FIG. 18, and the speed can be continuously adjusted in the low speed range from the neutral N to the forward second speed F2, and the forward speed 3 in the higher speed range. Specification that keeps the speed F3 to the fifth forward speed F5 stepwise, and can adjust the gear steplessly in the low speed range from the neutral N to the reverse second speed R2, and keeps the reverse third speed R3 engaged. It can also be.

  (8) The outer shape of the detent plate 64 is formed as shown in FIG. 19, and only the neutral N, forward fourth speed F4, and reverse second speed R2 are engaged and held, and other high speed ranges are continuously variable. It is possible to make it possible specifications.

  (9) The outer shape of the detent plate 64 is formed as shown in FIG. 20, and is held at each of the nine forward stages (F1 to F9), the neutral position N, and the six reverse stages (R1 to R6). It can also be a specification.

Overall side view of riding rice transplanter Overall plan view of the riding rice transplanter Side view showing neutral speed change operation unit Side view showing the shift operation unit in the forward shift state Side view showing the shift operation unit in the reverse shift state Side view showing the speed change operation unit in the state of forced neutral return operation Side view of the speed change operation unit Plan view showing a neutral positioning mechanism in the speed change operation unit Front view showing a part of the speed change operation unit The top view which shows the linkage structure of an accelerator operation part and an engine speed control mechanism The top view of the accelerator operation part which shows the accelerator up state by forward and reverse gear shift operation Side view showing detent structure of speed change operation unit Characteristic diagram showing the relationship between the shift operation position and engine speed Driving system transmission system diagram Work system transmission system diagram The top view which shows the accelerator operation part of another Example The side view which shows the principal part of the accelerator operation part of another Example. Side view showing another embodiment of the detent structure in the speed change operation unit Side view showing another embodiment of the detent structure in the speed change operation unit Side view showing another embodiment of the detent structure in the speed change operation unit

Explanation of symbols

12 Engine 31 Manipulator (hand accelerator lever)
41 Gearbox 53 Gearbox (Main gearshift lever)
91 Forward operation member 92 Reverse operation member 93 Link member (operation wire)
95 Speed control mechanism

Claims (6)

A gear shift operating tool that shifts a traveling gearbox and a speed control mechanism of an engine are linked so that the speed control mechanism is operated in a high speed direction as the gear shift operating tool is operated from neutral to a speed increasing direction. A shift operation structure of a working machine,
A speed change operation structure for a work machine, comprising an artificial operation tool for arbitrarily operating the speed control mechanism.   The shift operation structure for a work machine according to claim 1, wherein the artificial operation tool changes and adjusts an operation position of the speed control mechanism when the shift operation tool is neutral.   The speed change operation structure of the working machine according to claim 1 or 2, wherein a torque characteristic of the speed governing mechanism is set so that the torque efficiency of the engine is maximized when the human operating tool is at an operation limit position on a high speed side.   The engine rotation speed when the shift operation tool is operated to the maximum speed position is set higher than the engine rotation speed when the artificial operation tool is operated to the operation limit position on the high speed side. The shift operation structure for a work machine according to any one of claims 3 to 4.   The shift operation tool is configured to be operable over a forward range and a reverse range, and is configured to operate the speed control mechanism by displacing a common linkage member by an operation in the forward range and a reverse range. The speed change operation structure of the working machine according to any one of claims 1 to 4.   A forward operation member that is displaced by an operation of the shift operation tool toward the forward region; and a reverse operation member that is displaced by an operation of the reverse region; the forward operation member is connected to the speed control mechanism; 6. The shift operation structure for a work machine according to claim 5, wherein the forward operation member is operated in one-side operation by the reverse operation member while being interlocked with each other.

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