JP2009162253A - Speed change operation structure for working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve operability by simultaneously performing speed change operation and acceleration operation and enable traveling at low speed with a high engine output. <P>SOLUTION: As speed change operation of a transmission for traveling to a high speed side is performed, a speed control mechanism 98 of an engine 12 is operated to a high speed side, and an acceleration operating tool 30 capable of optionally manually operating the speed control mechanism 98 is provided. The maximum speed of the engine 12 which can be set by operating the acceleration operating tool 30 is set larger than the maximum speed of the engine 12 which can be changed in conjunction with the speed change operation. <P>COPYRIGHT: (C)2009,JPO&INPIT

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 gear and the speed control mechanism of the engine are linked, and the speed control mechanism is increased in speed as the speed change operation tool is operated from the neutral to the speed increasing direction. A configuration has been proposed in which a speed control mechanism can be operated even with an accelerator pedal separately provided with a speed control mechanism (see, for example, Patent Document 1).
JP 2006-204143 A

  According to the above speed change operation structure, when the speed change operating 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 operating tool in the speed increasing direction. Thus, by simultaneously performing the speed change operation and the speed control mechanism, the operability can be improved and the fuel efficiency can be improved. Furthermore, when operating while operating 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, that is, the engine output is low. Depending on the working conditions, there is a risk that the engine stop may occur due to an increase in work load or travel load, but it is possible to perform low speed travel at high engine output by arbitrarily increasing the engine speed by depressing the accelerator pedal. Is.

  In the conventional structure described above, the maximum engine speed that is set when the speed change operation tool is operated to the maximum speed and the maximum engine speed that is set when the accelerator pedal is fully depressed are set to be the same. In particular, when the traveling load becomes extremely large when traveling at low speeds or slow speeds in deep or viscous fields, the desired engine output can be obtained even if the accelerator pedal is fully depressed. There was a risk that the engine would stop without being able to.

  The present invention has been made paying attention to such points, and can improve the operability by simultaneously performing the speed change operation and the speed control mechanism, and can arbitrarily control the speed regardless of the speed change operation. An object of the present invention is to enable low-speed traveling without causing an engine stop in response to a particularly large traveling load while being capable of operating the mechanism.

A first aspect of the invention is a shift operation structure for a work machine configured to operate a speed control mechanism of an engine to a high speed side as a speed change operation of a traveling transmission device is performed to a high speed side.
The speed control mechanism is equipped with an accelerator operating tool that can be manually operated, and the maximum engine speed that can be set by operating the accelerator operating tool is higher than the maximum engine speed that can be changed in conjunction with the shifting operation. It is characterized by being set large.

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 as the speed change operation tool is operated in the speed increasing direction to increase the traveling speed, the engine speed increases. Output is increased.
By operating the accelerator operating tool to arbitrarily operate the speed control mechanism, it is possible to increase the engine output by appropriately increasing the engine rotational speed even when the speed change operation is operated at a low speed. In this case, if the accelerator operating tool is operated to the maximum speed position side, a higher engine rotation speed can be obtained than when the speed change operating tool is operated to the maximum speed shifting position, and traveling at a higher engine output becomes possible. .

  Therefore, according to the first invention, the operability can be improved by simultaneously performing the speed change operation and the speed control mechanism, and the speed control mechanism can be arbitrarily operated regardless of the speed change operation. However, it is possible to travel at a low speed without causing an engine stop corresponding to a particularly large traveling load.

According to a second invention, in the first invention,
The speed control mechanism is configured to operate at a higher rotational speed of the engine rotational speed set by operating the accelerator operating tool and the engine rotational speed changed in conjunction with the speed change operation. Is.

  According to the above configuration, the engine operating speed corresponds to the operating position of the shifting operation tool by operating the accelerator operating tool to the high speed side while operating the shifting operation tool at a position lower than the maximum shifting position. It can be made higher than the rotational speed of the engine. As a result, the accelerator operating tool does not have to be operated to the vicinity of the maximum speed position, so that the rotational speed of the engine is not unnecessarily increased.

According to a third invention, in the first or second invention,
A single linkage member linked to the first manipulation member linked to the speed control mechanism, a second manipulation member linked to the speed change operation system, and a second manipulation member linked to the accelerator operating tool. In addition to interlocking connection, only the operation force in the speed increasing direction of the second operation member and the third operation member can be transmitted to the first operation member.

According to the above configuration, the functions of the first and second inventions can be configured to operate reliably by mechanical linkage of the first, second, and third operation members, and can be configured simply. become.

  1 and 2 show a riding type rice transplanter with a fertilizer device as an example of a working machine. This riding type rice transplanter is a seedling configured in a six-row planting specification behind a riding type traveling machine body 3 having a pair of left and right front wheels 1 to be steered and a pair of right and left rear wheels 2 fixed in orientation. 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 a fertilizer device 7 is provided at the rear portion of the traveling machine body 3.

  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 steered to a boarding operation part located behind the engine 12. A steering handle 14 for operating, a driver's seat 15, a step 16 and the like are provided. Further, on the left and right of the front part of the traveling machine body 3, there are provided spare seedling platforms 17 for placing and accommodating spare seedlings in a plurality of stages. It has been.

  The seedling planting device 4 mounts seedlings for 6 lines, cuts out seedlings one by one from the lower end of the seedling platform 21 and the seedling platform 21 which are reciprocated by a set stroke in the left-right direction, and plantes them on the field. It consists of six rotary planting mechanisms 22 and three leveling floats 23 that level the planting location.

  The fertilizer application device 7 is mounted on the traveling machine 3 between the driver seat 15 and the seedling planting device 4, and a fertilizer hopper 24 that stores granular fertilizer, and fertilizer in the fertilizer hopper 24 is fed out by a set amount. The feeding mechanism 25, and the electric blower 28 that winds the fed fertilizer to the groove forming device 27 provided in each leveling float 23 via the supply hose 26, and the like are formed on the surface T by the groove forming device 27. It is configured to send fertilizer into the groove and bury it.

  15 and 16 show an outline of the transmission structure of the riding type rice transplanter. A hydrostatic continuously variable transmission (HST) 41 is connected to the side surface of the transmission case 9 as a transmission for main transmission that is belt-linked to the engine 12. The input is branched into a working 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 work power take-out shaft (PTO shaft) is passed through the inter-gear 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 interlocked with a single brake pedal 52 for stopping traveling provided at the right foot of the step 16. It is connected.

  The continuously variable transmission 41 is shifted by a main transmission lever (transmission operation tool) 53 disposed on the left side of the steering handle 14, and the auxiliary transmission mechanism 47 is disposed on the left side of the driver seat 15. Further, switching operation is performed by the auxiliary transmission lever 54. The differential device 48 of the front wheel 1 is differentially locked by depressing a differential lock pedal 55 at the foot, so that 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 FIG. 7, a support bracket 62 is fixed to the handle post 61 that supports the steering handle 14, and a detent plate 64 is placed around the fulcrum a on the left side of the support bracket 62 via a support shaft 63. The main transmission lever 53 is supported on the detent plate 64 so as to be swingable 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 around 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 FIG. 10, a guide plate 71 is fixed to the support bracket 62, and the main transmission lever 53 extends downward from a base portion into a stepped guide groove 72 formed in the guide plate 71. The guide rod 53a is penetrated, and the detent plate 64 is moved forward and backward by swinging the main transmission lever 53 back and forth along a predetermined step operation path by the engagement guide action of the guide groove 72 and the guide rod 53a. On the contrary, the continuously variable transmission 41 can be shifted in the range from the forward range to the reverse range by rotating.

  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 brake pedal 52 for stopping the airframe is depressed and operated. The lever 53 is forcibly returned to the neutral position N, and its structure is shown in FIGS.

  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.

  A check operation arm 85 is fixed to the other end of the pedal support shaft 84 to which the brake pedal 52 is connected, and the check operation member 81 is supported on a boss member 86 pivotally supported on the free end of the check operation arm 85. The rear end portion of the push-pull rod 87 extending rearward from the lower end of the rod 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 where the brake pedal 52 is not depressed and the main transmission lever 53 is in the neutral position N, and FIG. 4 is a forward movement where the brake pedal 52 is not depressed and the main transmission lever 53 is at the highest speed of forward movement. FIG. 5 shows a state in which the main transmission lever 53 is in the reverse third speed R3 which is the highest reverse speed without the brake pedal 52 being depressed.

  According to this, when the brake pedal 52 is depressed while the main transmission lever 53 is in the forward transmission operation path F (for example, the state shown in FIG. 4), the check operation arm 85 is rotated counterclockwise in the figure. The push-pull rod 87 is protruded 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.

  When the main transmission lever 53 reaches the neutral position N, as shown in FIG. 6, the second contact pin 83 also contacts the check fitting 81a, and the first contact located on both the upper and lower sides of the fulcrum c. Since the 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.

  The initial compression force applied by the compression coil spring 88 is set to be larger than the operation force necessary 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 set. Is not compressed and deformed by the reaction force. When the brake pedal 52 is further depressed after the main transmission lever 53 reaches the neutral position N, the check operation arm 85 is moved against the push-pull rod 87 which cannot move forward, and the compression coil spring 88. Is further compressed and deformed, and is rotated counterclockwise in the figure, thereby ensuring a sufficient brake operation stroke.

  When the brake pedal 52 is depressed while 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 figure to push and pull the rod 87. Is projected forward (leftward in the figure), and the check operation member 81 is pivoted 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 When the first contact pin 81 and the second contact pin 83 located at the contact position 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. 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 cannot move forward.

  When the brake pedal 52 is depressed and the main transmission lever 53 is forcibly returned toward the neutral position N, if the depression is stopped before reaching the neutral position N, the main transmission lever 53 depresses the brake pedal 52. The gear is decelerated to a shift position corresponding to the position and held at that position. Accordingly, the traveling speed can be reduced only by foot operation while using both hands for the steering handle 14 and other operations, which is effective in improving operability.

  As shown in FIG. 10, a speed adjusting lever 99 of a mechanical speed adjusting mechanism (mechanical governor) 98 equipped in the engine 12 is oscillated and biased to a low speed “L” side by a return spring 100. By pulling the first operating wire 31 and swinging the speed adjusting lever 99 to the high speed “H” side against the return spring 100, the rotational speed of the engine 12 can be increased and the engine output can be increased. The first operation wire 31 is loosened and the speed adjusting lever 99 is urged and swung toward the “low speed” side, thereby lowering the rotational speed of the engine 12 and lowering the engine output.

  The first operation wire 31 as a first operation member for operating the speed control mechanism 98 is connected to the main transmission lever 53 and the accelerator pedal 30 as an accelerator operation tool provided on the right side of the brake pedal 52. Are linked together.

  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 a second operation wire 93 as a second operation member for operating the speed adjusting mechanism 98 is connected to an end portion of the forward operation member 91, and a rear end of the outer wire 93o is fixed in position. It is supported by the metal fitting 94. A return spring 95 that swings and urges the forward operation member 91 in a direction to pull back the inner wire rear portion 93ir to the outer wire side is connected to the end of the forward operation member 91, and the forward operation member 91 is moved in the biasing direction. The swing limit is restricted by the stopper 96 of the guide plate 71.

  The reverse operation member 92 extends beyond the fulcrum h, and an engagement piece 92a bent and erected at the end thereof is engaged with the end of the forward operation member 91 from the biased swinging direction. The return swing limit of the reverse operation member 92 is restricted by the stopper 97 of the guide plate 61.

  The accelerator pedal 30 is stepped around a fulcrum j and supported so as to be swingable, and is linked to an upper end portion of an operation arm 32 supported so as to be swingable around a fulcrum k by a long hole and a pin. The accelerator pedal 30 is urged to return by being urged to swing by 33. An inner wire rear portion 34ir of a third operation wire 34 as a third operation member for operating the speed adjusting mechanism 98 is connected to the lower end portion of the operation arm 32.

  The rear end of the outer wire of the first operation wire 31 is connected to the front end of the linkage case 35 formed in a cylindrical shape, and the outer wire front end of the second operation wire 93 and the outer wire front end of the third operation wire 34 are connected to the linkage case 35. The inner wire rear portion 31ir of the first operation wire 31, the inner wire front portion 34if of the second operation wire 34, and the inner wire front portion 34if of the third operation wire 34 are connected to the rear end, and inside the linkage case 35. The linkage members 36 are linked together.

  As shown in FIG. 13, the linkage member 36 is incorporated in the linkage case 35 so as to be slidable in the wire longitudinal direction, and the inner wire rear portion 31ir of the first operation wire 31 moves back and forth with respect to the linkage member 36. A large diameter contact portion 31h is provided at the rear insertion end of the inner wire rear portion 31ir, and the linkage member 36 can be operated to move forward only when the inner wire rear portion 31ir is pulled forward. It is like that. On the other hand, the inner wire front portion 93if of the second operation wire 93 is inserted into the linkage member 36 so as to be movable back and forth, and a large diameter contact portion 93h is provided at the front insertion end of the inner wire front portion 93if. Only when the inner wire front portion 93if is pulled backward, the linkage member 36 can be operated to contact and move backward. Furthermore, the inner wire front portion 34if of the third operation wire 34 is inserted into the linkage member 36 so as to be movable back and forth, and a large diameter contact portion 34h is provided at the front insertion end of the inner wire front portion 34if. Only when the inner wire front portion 34if is pulled backward, the linkage member 36 can be moved backwardly.

  By pulling the second operation wire 93 or the third operation wire 34 backward, the linkage member 36 is slid rearward according to the amount of wire operation on the side that is largely pulled, whereby the first operation wire 31 is moved. Is pulled backward, and the speed control lever 99 of the speed control mechanism 98 is operated to the “high speed” side. By loosening the second operation wire 93 and the third operation wire 34, the linking member 36 can be slid forward in accordance with the amount of loosening of the wire on the side with less looseness, whereby the first operation wire 31 is loosened. The speed adjusting lever 99 of the speed adjusting mechanism 98 is actuated to the “low speed” side by the return biasing force.

  As shown in FIG. 11A, when the main transmission lever 53 is operated to the forward transmission operation path F beyond the forward neutral position Nf in a state where the accelerator pedal 30 is not depressed, the forward operation member 91 is pivoted in the clockwise direction in the drawing against the return spring 99, and the inner wire rear portion 93ir of the operation wire 93 is pulled out, whereby the inner wire front portion 93if is pulled into the outer wire 93o, and the speed control lever 96 is pulled. Is displaced to the “high speed” side, and the rotational speed of the engine 12 is increased. 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 shown around the fulcrum h. The forward operation member 91 swung in the clockwise direction and connected to the reverse operation member 92 via the engagement piece 92a is swung in the clockwise direction in FIG. The 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, and the rotational speed of the engine 12 is increased.

  The main transmission lever 53 is urged laterally around the fulcrum b by the torsion spring 90, and in the free state left at the neutral position N, 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 rotation 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.

  When the main transmission lever 53 is operated to the reverse operation path R including the reverse side neutral Nr and the reverse operation member 92 is swung, this is detected by the switch 103 attached to the guide plate 71. ing. 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 forcibly raise the seedling planting device 4 at the rear of the machine when the machine is moved backward in the field and to avoid colliding with a cocoon, etc. Rapid ascent control is desired. Here, as described above, since the rotational speed of the engine 12 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 increases. Rapid rise control can be executed.

  Here, when the accelerator pedal 30 is depressed while the main transmission lever 53 is positioned at the forward side neutral Nf, the inner wire front portion 34if of the third operation wire 34 is pulled backward according to the amount of depression, Thus, the first operation wire 31 is pulled backward, and the speed control lever 99 is operated to the “high speed” side against the return spring 100. As a result, the minimum rotational speed of the engine 12 when the main transmission lever 53 is in the forward side neutral Nf can be arbitrarily set higher than the idling rotational speed n0.

  Therefore, when it is difficult to start the engine 12 in a cold or cold region, the accelerator pedal 30 is slightly depressed to bring the accelerator up state while the main transmission lever 53 is positioned at the forward neutral position Nf. The engine 12 can be reliably started.

  When the speed change lever 53 is operated to the maximum forward speed position (forward 5th speed F5), the speed control lever 99 is not yet operated to the maximum speed set position. In this state, the accelerator pedal 30 is depressed to the limit position. Then, the speed control lever 99 is set to be operated further to the high speed side. That is, as shown in FIG. 14, the maximum rotational speed (for example, 3200 rpm) n1 of the engine 12 when the accelerator pedal 30 is depressed to the maximum is the maximum of the engine 12 when the shift lever 53 is operated to the maximum shift position. The rotational speed (for example, 2800 rpm) is set to be higher than n2.

  According to this, by depressing the accelerator pedal 30 to the maximum, the output of the engine 12 can be particularly large compared to the normal travel where the depressing of the accelerator pedal 30 is released and the shift operation is performed, In addition, even when the traveling load becomes extremely large when traveling at a low speed or a low speed in a viscous field, etc., the operation can be continued without stopping the engine by operating the accelerator pedal 30.

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

  (1) As the accelerator operating tool 30, a hand accelerator lever that can be held at an arbitrary operation position can be used. In this case, in conjunction with the depression of the brake pedal 52, not only the main transmission lever 53 but also the operated hand accelerator lever (accelerator operating tool 30) is forcibly returned to the idling position. The aircraft can be stopped immediately.

  (2) As a structure for linking the forward operation member 91 and the speed control lever 99, as described above, the operation wires 31, 93, 34 are used as the first, second, and third operation members. A combined link mechanism can also be used. In this case, the first operation member linked to the speed control lever 99, the second operation member linked to the speed change operation tool 53, and the third operation member linked to the accelerator operation tool 30 are formed in a single link member with a long hole. By interlocking and connecting via an interchangeable means using pins, it is possible to function in the same manner as the wire-type linkage structure described above.

  (3) As the transmission 41 for traveling, besides using a hydrostatic continuously variable transmission (HST), 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.

  (4) As a shift operating tool for operating the traveling transmission 41, a shift pedal may be used in addition to the shift lever.

  (5) As the speed control mechanism 98 of the engine 12, an electronic governor can be used in addition to the mechanical type. In this case, the operation position of the speed change operation tool and the operation position of the accelerator operation tool can be electrically detected by a potentiometer or the like, respectively, and the electronic governor can be controlled with characteristics preset with respect to the operation position. In the case of such an electrically controlled type, the accelerator operating tool can be selected from various specifications such as a slide knob type and a rotary dial type as well as a lever type.

  (6) In the embodiment, the shape of the reverse operation member 92 is set so that the accelerator is raised when the main transmission 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.

Overall side view of riding rice transplanter Overall plan view of 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 shift 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 Linkage diagram showing operation structure of 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 Sectional drawing which shows the operating state of the principal part in an accelerator operation system Characteristic diagram showing the relationship between the shift operation position and engine speed Driving system transmission system diagram Work system transmission system diagram

Explanation of symbols

DESCRIPTION OF SYMBOLS 12 Engine 30 Accelerator operation tool 31 1st operation member 34 3rd operation member 36 Linking member 41 Transmission 93 Second operation member 98 Speed control mechanism

Claims (3)

A shift operation structure of a work machine configured to operate a speed adjusting mechanism of an engine to a high speed side as a speed change operation of a traveling transmission device is performed to a high speed side,
The engine speed control mechanism is provided with an accelerator operation tool that can be manually operated, and the maximum engine speed that can be set by operating the accelerator operation tool can be changed in conjunction with the speed change operation. A speed change operation structure of a work machine, characterized in that it is set to be larger than that.   The speed control mechanism is configured to be operated at a higher rotation speed of an engine rotation speed set by operating the accelerator operation tool and an engine rotation speed changed in conjunction with a shift operation. The shift operation structure for a work machine according to claim 1.   A single linkage member linked to the first manipulation member linked to the speed control mechanism; a second manipulation member linked to the speed change operation system; and a third manipulation member linked to the accelerator operating tool. And the second operating member and the third operating member in a speed increasing direction can be transmitted to the first operating member. Operation structure.

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