JP2006204143A - 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 to operate a speed regulation mechanism in a speed increasing side according to the speed increasing operation of a speed change operation tool from a neutral position by interlocking the speed change operation tool of a walking-type speed change apparatus with the speed regulation mechanism of an engine, enabling the traveling motion with arbitrary engine output by a pedal operation in spite of the ability to improve the operationality by the simultaneous operation of the speed change operation and the acceleration operation and continuing the traveling motion without causing deceleration even by an unintentional or careless pedal operation miss. <P>SOLUTION: An automatically returning accelerator pedal 30 is connected to a speed regulation mechanism 95 in an interlocked manner and the acceleration of the speed regulation mechanism 95 is set to the high-speed side rotation speed of the engine between the engine rotation speed set by the operation of the speed change operation tool 53 and the engine rotation speed set by the depression of the accelerator pedal 30. <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 control mechanism of the engine is operated by the electric motor based on the operation position detection information of the speed change lever for operating the transmission for traveling, and the speed change lever is operated from the neutral to the speed increasing direction. Accordingly, the speed control mechanism is configured to set the accelerator in the high speed direction with a predetermined change characteristic, and when the depression of the separately installed accelerator pedal is detected, the speed control mechanism has priority over the accelerator operation system by the electric motor. Has been proposed that is operated to a position corresponding to the pedal depression amount (see, for example, Patent Document 1).
JP 2002-293171 A

  According to the above speed change operation structure, when the speed change lever is operated to the neutral position, a predetermined idling state is established, and as the speed change lever is operated in the speed increasing direction and the traveling speed is increased, the engine speed is also increased. The operability can be improved by simultaneously performing the speed change operation and the accelerator operation, and it is also effective in improving the fuel consumption. In this case, since the idling rotation speed when the speed change lever is operated to the neutral position is constant, if the speed change lever is slightly operated from the neutral position and the work is performed at low speed, the engine speed is the idling speed. The speed is slightly higher than the speed, and the work is performed with a low engine output. Depending on the work conditions, there is a possibility that the engine stops due to an increase in work load or travel load. Therefore, in such a case, by depressing the accelerator pedal, the accelerator can be arbitrarily raised in preference to the accelerator set by the shift lever, and the low speed running can be continued without causing an engine stop. is there.

  However, in the above structure, as soon as the depression of the accelerator pedal is detected, the accelerator set by the shift lever is ignored, and the accelerator set according to the amount of depression of the accelerator pedal is made. If you put your foot on the accelerator pedal and depress the pedal more than the amount of play, this will be detected and the speed control mechanism will be set according to the pedal depressing amount, and the engine speed will be almost the same as idling. The accelerator will be lowered to the speed, and the engine may be stopped depending on the work load or the traveling load.

  The present invention has been made paying attention to such points, and it is possible to improve operability by simultaneously performing a shift operation and an accelerator operation. The main purpose is to make it possible to continue traveling without being depressed by unconscious or careless pedal operation during traveling.

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 accelerator pedal that is automatically restored is linked to the speed control mechanism, and an engine rotation speed that is set based on an operation of the shift operation tool and an engine rotation speed that is set based on a depressing operation of the accelerator pedal. Of these, the speed control mechanism is configured to be accelerator-set to the engine speed on the high speed side.

  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. Engine output is increased. In addition, when the accelerator pedal is depressed during traveling with the shift operation tool being operated to an arbitrary shift position, the engine rotation speed set based on the depression operation is set based on the operation of the shift operation tool Only when the rotational speed is greater than the rotational speed, the engine rotational speed is set to the engine rotational speed set based on the depression operation of the accelerator pedal, and the engine rotational speed is increased.

  That is, even if the accelerator pedal is depressed during driving, the accelerator set remains constant until the engine speed set based on the pedal depression becomes higher than the engine speed set based on the operation of the speed change operation tool. The accelerator set state corresponding to the pedal is not reached until the accelerator pedal is fully depressed.

  Therefore, according to the first invention, it is possible to improve the operability by simultaneously performing the speed change operation and the accelerator operation, and it is also possible to run at any engine output by the pedal operation, In addition, even if the accelerator pedal is depressed unintentionally or carelessly while driving, it is possible to continue driving without lowering the accelerator, which makes it easy to handle a wide range of loads and driving. I was able to do it.

According to a second invention, in the first invention,
The swing fulcrum of the accelerator pedal is installed near the step surface.

  According to the above configuration, the amount of pedal displacement near the step when the accelerator pedal is depressed and swung is reduced, and the opening for inserting the pedal formed in the step can be made small.

According to a third invention, in the first or second invention,
An accelerator operation arm that can swing around a swing fulcrum parallel to the pivot fulcrum of the accelerator pedal is disposed below the accelerator pedal, and one end of the accelerator operation arm and the accelerator pedal are linked to each other and the accelerator operation is performed. The other end of the arm and the speed control mechanism are mechanically interlocked and connected.

  According to the above configuration, the accelerator operation arm can be swung by expanding the accelerator pedal stepping rotation angle by separately providing the accelerator pedal rotation fulcrum and the accelerator operation arm swing fulcrum. As a result, the accelerator pedal's stepping angle can be reduced while the accelerator operating arm is swung as necessary and sufficiently, and the angle change of the tread surface of the accelerator pedal is relatively small, resulting in excellent stepping operability. It becomes.

A fourth invention is the invention according to any one of the first to third inventions,
A contact restricting structure for restricting the swing limit of the accelerator pedal by restricting the relative posture of the accelerator pedal and the accelerator operating arm at the interlocking connection portion between the accelerator pedal and the accelerator operating arm is provided. It is.

  According to the above configuration, the swing limit of the accelerator pedal is determined between the accelerator pedal and the accelerator operation arm. For example, a stopper that controls the contact of the accelerator pedal or the accelerator operation arm is separately provided on the body fixing portion such as a step. There is no need, and the contact regulation structure can be configured easily.

According to a fifth invention, in any one of the fourth inventions,
The contact restriction structure is configured such that the swing limit in the depression direction of the accelerator pedal and the swing limit in the return direction are contact restricted.

  According to the above configuration, it is possible to restrict the normal and reverse swing limits with one contact regulation structure, which is effective in simplifying the contact regulation structure.

A sixth invention is the invention according to any one of the first to fifth inventions,
The accelerator operation arm is oscillated and biased by a return spring.

  According to the above configuration, it is possible to reliably perform the return operation of the accelerator operation arm mechanically linked to the speed control mechanism, compared to the case where the return spring is attached to the accelerator pedal to indirectly return the accelerator operation arm.

  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 rubber mat laying step 16 and the like are provided, and spare seedling platforms 17 for placing and accommodating spare seedlings in a plurality of stages are provided on the left and right sides of the front of the machine body. Is provided.

  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 set amount of fertilizer in the fertilizer hopper 24. A feeding mechanism 25 that feeds the fertilizer one by one, and an electric blower 28 that wind-feeds the fed fertilizer to the grooving device 27 provided in each leveling float 23 via the supply hose 26, and the like. It is configured to feed and fertilize fertilizer in the formed groove.

  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 speed change operation structure of the continuously variable 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 arm 85 is pivotally supported by a boss member 86 pivotally supported at the free end. A rear end portion of the push-pull rod 87 extending rearward from the lower end of the operating 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. The inner wire rear portion 93ir of the operation wire 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 bracket 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 of 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. The return swing limit of the reverse operation member 92 is restricted by the stopper 101 of the guide plate 71.

  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 that is operated in conjunction with the speed change operation of the main speed change lever 53 is also artificially operated by depressing the accelerator pedal 30 disposed at the right front side of the pedal 52 for stopping traveling. In the following, the structure will be described with reference to FIGS.

  A pair of left and right stays 19 are provided on the lower surface of a step support frame 18 having a sheet metal press structure extending rightward from the machine body frame 8 so as to face the vertical plate. Is pivotally connected around the pivot point P in the horizontal direction. The accelerator pedal 30 is configured by covering a pedal body 30 a having a sheet metal structure with a rubber material 30 b, and the rotation fulcrum P is set to be positioned near the surface of the step 16.

  A bell crank-type accelerator operating arm 32 can swing around a swinging fulcrum Q parallel to the pivoting fulcrum P via a fulcrum shaft 33 at the front (left side in the figure) of the pivoting fulcrum P. The lower surface of the front portion of the accelerator pedal 30 is received and supported by a roller 35 attached to the front end portion of the upper side 32a of the accelerator operation arm 32 via a support shaft 34. Further, a U-shaped bent metal fitting 36 is fixed to the lower surface of the front portion of the accelerator pedal 30, and the support shaft 34 is inserted into a longitudinally long hole 37 formed therein. Further, a return spring 105 is stretched between the lower side 32b of the accelerator operation arm 32 and the support fitting 38 attached to the step support frame 18 so that the upper side 32a of the accelerator operation arm 32 is swung up and swung. The operation arm 32 is oscillated and biased.

  Accordingly, when the accelerator pedal 30 is depressed, the accelerator operation arm 32 connected to the accelerator pedal 30 is swung against the return spring 105, and when the depression operation is released, the accelerator operation arm 32 is returned to the energized state. By swinging, the accelerator pedal 30 is returned and rotated upward. The accelerator operating lever 32 that swings back and forth is supported by contact with a stopper pin 106 mounted on the stay 19, thereby restricting the return limit.

  Here, since the accelerator operating lever 32 is swingably supported around the swing fulcrum Q ahead of the pivot fulcrum P of the accelerator pedal 30, the accelerator operating arm 32 can be moved with respect to the stepping rotation angle of the accelerator pedal 30. The swing angle will be enlarged. Further, as the accelerator pedal 30 is depressed, the roller 35 moves relatively forward, and the support shaft 34 moves forward in the front / rear elongated hole 37. Further, when the support shaft 34 is brought into contact with the front end of the front / rear elongated hole 37, further depression of the pedal becomes impossible.

  A rear end of the outer wire of the second operation wire 107 is connected to and supported by the support fitting 38, and an inner wire rear portion 107ir of the second operation wire 107 is connected to a front end portion of the lower side 32b of the accelerator operation arm 32. Then, as shown in FIG. 10, the front end of the outer wire 107o in the second operation wire 107 is connected and supported to the wire receiving portion 96a of the speed control lever 96, and the inner wire front portion 107if led out from the front end of the outer wire 107o, The operation wire 93 is connected and supported by a wire catch 98 that supports and supports the inner wire front portion 93if.

  According to the above configuration, when the main speed change lever 53 is in the forward neutral position Nf in a return state where the accelerator pedal 30 is not depressed, the two inner wire front portions 93if and 107if connected to the wire catch 98 are not slackened. In this state, 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, when the accelerator pedal 30 is depressed to an arbitrary position while the main transmission lever 53 is positioned at the forward side neutral Nf, the inner wire rear portion 107ir of the second operation wire 107 is pulled according to the amount of depression. As a result, the inner wire front portion 107if is pulled in, the speed adjusting lever 96 is operated to the “high speed” side against the return spring 102, and when the accelerator pedal 30 is released, the original idling state is restored. As a result, the engine speed when the main speed change lever 53 is in the forward side neutral Nf can be arbitrarily increased by stepping on the pedal.

  Therefore, when it is difficult to start the engine in a cold or cold region, the accelerator pedal 30 is depressed slightly to the high speed side while the main transmission lever 53 is positioned at the forward neutral position Nf, resulting in an accelerator-up state. Thus, the engine can be reliably started.

  Further, in the state where the main transmission lever 53 is operated to the traveling position, the speed control lever 96 is displaced to the high speed side by the pulling operation of the operation wire 93, so the inner wire front portion 107if of the second operation wire 107 is loosened. Therefore, even if the accelerator pedal 30 is depressed and the second operating wire 107 is pulled in this state, the governor lever 96 does not move until the inner wire front portion 107if is loosened, and the inner wire front portion After the looseness of 107if has disappeared, the accelerator pedal 30 is further depressed to pull the second operation wire 107, whereby the inner wire front portion 107if is retracted, and the speed control lever 96 is relatively moved to the high speed side. It will be displaced and the accelerator will be up.

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

  (1) As shown in FIG. 18, the pedal arm 30c provided in the accelerator pedal 30 is extended downward, and the return spring 105 and the inner wire 107i of the second operation wire 107 are attached to the pedal arm 30c. You can also. In this case, the range of swinging of the pedal arm 30c may be restricted by the stopper pins 106 attached to the front and rear of the stay 19, and the operating range of the accelerator pedal 30 may be restricted.

  (2) The shape and size of the accelerator pedal 30 can be arbitrarily set. For example, as shown in FIG.

  (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 speed change operating tool for operating the continuously variable transmission 41, a pedal may be used in addition to the lever.

  (5) As the speed control mechanism 95 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 pedal are set with a potentiometer or the like. It is also possible to control the electronic governor with characteristics that are electrically detected and preset with respect to the operation position.

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

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 Longitudinal side view of the accelerator pedal Front view of accelerator pedal Vertical side view showing an accelerator pedal of another embodiment A longitudinal side view showing an accelerator pedal of still another embodiment.

Explanation of symbols

12 Engine 30 Accelerator pedal 32 Accelerator operating arm 41 Transmission device 53 Shifting operation tool (main transmission lever)
95 Speed control mechanism 105 Return spring P Swing fulcrum of accelerator pedal Q Swing fulcrum of accelerator operating arm

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,
An accelerator pedal that is automatically restored is linked to the speed control mechanism, and an engine rotation speed that is set based on an operation of the shift operation tool and an engine rotation speed that is set based on a depressing operation of the accelerator pedal. A speed change operation structure for a working machine, wherein the speed control mechanism is accelerator-set at a high engine speed.   The shift operation structure for a work machine according to claim 1, wherein a swing fulcrum of the accelerator pedal is installed near a step surface.   An accelerator operating arm that can swing around a swinging fulcrum parallel to the turning fulcrum of the accelerator pedal is disposed below the accelerator pedal, and one end of the accelerator operating arm and the accelerator pedal are linked to each other and the accelerator operation is performed. The shift operation structure for a working machine according to claim 1 or 2, wherein the other end portion of the arm and the speed control mechanism are mechanically linked to each other.   A contact restricting structure for restricting a swing limit of the accelerator pedal by restricting a relative posture between the accelerator pedal and the accelerator operating arm is provided at an interlocking connection portion between the accelerator pedal and the accelerator operating arm. Item 4. A work gear shift operation structure according to any one of Items 1 to 3.   The shift operation structure for a work machine according to claim 4, wherein the contact restriction structure is configured to restrict contact between a swing limit in a stepping direction of the accelerator pedal and a swing limit in a return direction.   The shift operation structure for a working machine according to any one of claims 1 to 5, wherein the accelerator operation arm is oscillated and biased by a return spring.

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