JP4070737B2 - Combine steering device - Google Patents

Description

  The present invention relates to a combine steering device including a pair of left and right crawler type traveling devices.

As the steering device, for example, as disclosed in Patent Document 1, each of the pair of left and right crawler type traveling devices is equipped with a side clutch, and one traveling device with the side clutch disengaged, A slow turning drive means that drives in the same direction as that of the other traveling device in which the side clutch is not disengaged and at a speed lower than its operating speed, and a rapid turning drive means that brakes one traveling device in which the side clutch is disengaged When the steering operating tool is operated in the first operating area that is shifted to the left or right from the neutral position, the side clutch of one of the traveling devices is disengaged and is operated in the subsequent second operating area. When the traveling device with the side clutch disengaged is decelerated and driven by the gentle turning drive means and further operated into the subsequent third operation region, the side clutch is disengaged. The running device so as to brake by the brake mechanism, the steering operation member and the side clutch, the slow rotation drive means, and, that in conjunction with said braking means is proposed.
JP 7-47973 A

  The steering device becomes effective as the turning function gradually increases as the amount of operation of the steering operation tool increases, and is effective in performing smooth aircraft turning. The relationship was not yet fully considered. That is, in farm work machines such as combine machines, there are two types of maneuvering during work running: steering for causing the machine to follow a crop row and steering for greatly changing the direction of the machine at the edge.

  Here, in the operation to make the aircraft follow the crop line, if the aircraft is inadvertently largely steered, the crop may be damaged or the harvest may be lost. It is necessary to perform the steering operation with care. Further, in the steering for largely changing the direction of the aircraft at the shore, if the steering of the aircraft is slow, the turning space becomes large, and it is necessary to quickly make a small turn.

  The main object of the present invention is to provide a steering device that can easily perform the steering operation required for such a combine.

  [Configuration, operation and effect of the invention according to claim 1]

(Structure) The steering device for a combine according to the first aspect of the present invention includes a pair of left and right crawler-type traveling devices, and is neutral in an operating range from a neutral position of a single steering operation tool to one of the left and right turning directions. In the steering device for a combine that forms a plurality of operation areas so that the turning function increases as the distance from the position increases,
The operating range, one of the traveling device on the other of the operating device in the same direction, and includes a slow turning operation region to perform gentle swirling and the deceleration drive at a lower speed than the other of the operating device Rutotomoni, the slow rotation operation range An operation area with higher turning performance than the gentle turning operation area
In the slow turning operation area, the turning performance in the slow turning operation area is set so that the turning function becomes higher as the steering operation tool moves away from the neutral position,
The operable range in the gentle turning operation area is set larger than the other operation areas of the plurality of operation areas.

(Effect) According to the above configuration, in the work traveling in the field, by slightly operating from the neutral position of the steering operation tool to one of the left and right turning directions, the aircraft body steering is started and the crop line is aligned. For normal steering, operation in the gentle turning operation area is sufficient. In this case, since the slow turning operation area is larger than the other operation areas, the aircraft will accidentally deviate from the slow turning operation area during normal steering to follow the crop row. Is less likely to be unjustly steered.

(Effect) Therefore, according to the invention according to claim 1, by rationally setting the region of the operation area, it is possible to appropriately perform the aircraft steering during the work traveling without excessive steering. At the same time, it was possible to easily and easily make small turns such as turning at the shore and turning on the road, and the steering operability as a combine could be improved.

  [Configuration, operation and effect of invention of claim 2]

(Structure) The steering apparatus for a combine of the invention according to claim 2 is the invention according to claim 1, wherein a brake operation area is provided outside the gentle turning operation area.

(Operation) According to the above configuration, the one traveling device with the side clutch disengaged can be braked and stopped, and the airframe can be reliably turned slightly by driving only the other traveling device with the side clutch not disengaging.

(Effects) Therefore, according to the invention according to claim 2, the steering characteristics of the respective operation areas can be made different from each other, which brings about the above-mentioned effects of the invention of claim 1, and further smoother and more accurate aircraft steering. Will be able to do.

  FIG. 1 is a right side view of a combine to which the present invention is applied. This combine is connected to a front part of a traveling machine body 2 having a pair of left and right crawler type traveling devices 1L and 1R, and a cutting pretreatment unit 3 is connected to be movable up and down, and a threshing device 4 and a grain tank are mounted on the machine body. 5, the engine 6, the control unit 7, and the like are mounted.

  Hereinafter, the transmission structure of the traveling devices 1L and 1R will be described based on FIG. 2, FIG. 3, and FIG. 4, but the descriptions in the left and right directions in the description are based on the left and right directions of the aircraft and are viewed from the front. This is the opposite of the horizontal direction in the figure.

  The power of the engine 6 is transmitted to a hydrostatic continuously variable transmission (HST) 8 as a main transmission capable of switching between forward and backward travel, and the shift output is transmitted to a transmission case 9. The power input to the transmission case 9 is transmitted to the first shaft 10 through the gears G1 and G2, and then transmitted to the auxiliary transmission mechanism 11 through the gears G3 and G4. Of the power extracted from the first shaft 10 to the outside of the case, only the normal rotation power is transmitted to the pre-cutting processing unit 3 via the one-way clutch OC. The hydrostatic continuously variable transmission 8 is operated by a main transmission lever 29 provided in the control unit 7.

  The sub-transmission mechanism 11 performs a three-stage gear shift in a constant mesh manner. A small-diameter gear G5, a medium-diameter gear G6, and a large-diameter gear G7 that are loosely fitted to the second shaft 12 are connected to a third shaft 13. The gears G8, G9, and G10 fixed to each other are always meshed with each other, and the two shift sleeves S1 and S2 provided on the second shaft 12 are shifted so that any one of the three pairs of normally-engaged gears is obtained. It is configured to perform transmission transmission from the second shaft 12 to the third shaft 13.

  That is, as shown in FIGS. 5 and 6, the shift sleeves S1 and S2 are a pair of shift forks 15a and 15b provided on a shifter 15 that slides and moves along a support shaft 14 that is horizontally supported in the transmission case. The shift sleeves S1, S2 are simultaneously shifted in the same direction in accordance with the sliding displacement of the shifter 15. An operation arm 16a that engages with the shifter 15 is provided at the tip of the speed change operation shaft 16 that is inserted through the transmission case 9 in the front-rear direction, and the auxiliary speed change lever 30 provided in the control unit 7 is operated. By rotating the speed change operation shaft 16, the shifter 15 is slid right and left.

  Here, the shift sleeve S1 is directly splined to the second shaft 12 over the entire shift range, whereas the shift sleeve S2 is fitted to the boss portion of the gear G6 and the second shaft 12 by spline fitting. The spline collar 17 and the boss of the gear G7 can be shifted, and a three-speed shift is performed as follows.

  When the shifter 15 is in the low speed "L" position, as shown in FIG. 7, the shift sleeve S1 is engaged with the boss portion of the gear G5 over the second shaft 12, and the shift sleeve S2 is engaged with the boss portion of the gear G6. And the power of the second shaft 12 is transmitted to the third shaft 13 at a low speed via the shift sleeve S1 and the gears G5 and G8. When the shifter 15 is in the medium speed “M” position, as shown in FIG. 8, the shift sleeve S1 is supported only on the second shaft 12, and the shift sleeve S2 is connected to the boss portion of the gear G6 and the spline collar. 17, the power of the second shaft 12 is transmitted at a medium speed to the third shaft 13 through the spline collar 17, the shift sleeve S2, and the gears G6 and G9. When the shifter 15 is in the neutral “N” position, the shift sleeve S1 is supported only on the second shaft 12 and the shift sleeve S2 is supported only on the spline collar 17 as shown in FIG. The power transmission from the second shaft 12 to the third shaft 13 is interrupted. When the shifter 15 is in the high speed “H” position, as shown in FIG. 10, the shift sleeve S1 is supported only on the second shaft 12, and the shift sleeve S2 is connected to the boss portion of the gear G7 and the spline collar 17. Thus, the power of the second shaft 12 is transmitted to the third shaft 13 through the spline collar 17, the shift sleeve S2, and the gears G7 and G10 at a high speed.

  As shown in FIG. 6, the shifter 15 uses a ball detent 18 to reduce the low speed “L” that is the harvesting speed of the fallen cereal, the medium speed “M” that is the standard harvesting speed, and the neutral “N”. ”And the high speed“ H ”that is the moving speed.

  The power transmitted to the third shaft 13 as described above is transmitted to the center gear G11 of the fourth shaft 19 through the center gear G9, and then the left and right side clutches 20L and 20R, the axle gear 21L, 21R and axles 22L and 22R are transmitted to the left and right traveling apparatuses 1L and 1R.

  As shown in FIG. 4, the side clutches 20L, 20R are shifted to the center gear G11 by shifting the side clutch gears 23L, 23R that are loosely fitted to the fourth shaft 19 and always engaged with the axle gears 21L, 21R. The center inner teeth are engaged and disengaged from the side so that power transmission from the center gear G11 to the axles 22L and 22R is interrupted. Means for shifting the side clutch gears 23L and 23R are as follows. It is configured as follows.

  The fourth shaft 19 is configured as a stepped shaft having a large diameter at the central portion, and the side clutch gears 23L and 23R are steps that are fitted over the large diameter portion and the small diameter portion of the fourth shaft 19. It is normally slid and biased toward the center gear G11 by the spring 24, and is held at the clutch engagement position. Then, the pressure oil is supplied through the oil passages a and b drilled in the fourth shaft 19 so that the side clutch gears 23L and 23R are shifted to the clutch disengagement position against the spring 24. It has come to be. Further, when the side clutch gears 23L and 23R are shifted to the clutch disengagement position disengaged from the center gear G11, the oil passages a and b for supplying pressure oil are provided in the oil passage formed in the fourth shaft 19. It is configured to communicate with d.

  Further, the side clutch gears 23L and 23R are further shifted beyond the clutch disengagement position where the engagement with the center gear G11 is disengaged, so that the steering side gears that are loosely fitted to both end portions of the fourth shaft 19 are mounted. It can be connected to 25L and 25R from the side. The steering side gears 25L and 25R are engaged with gears 27L and 27R fixed to both end portions of the fifth shaft 26, and the gear G13 loosely fitted to the fifth shaft 26 is connected to the center gear G11. It is meshed with a small-diameter gear G12 connected to the side and decelerated.

  Between the gear G13 and the fifth shaft 26, a multi-plate clutch C that performs gentle turning is provided. In this clutch C, the piston 32 is normally retracted and returned by the internally mounted spring 31 and is maintained in the clutch disengaged state, and pressure oil is supplied through an oil passage c drilled in the fifth shaft 26. As a result, the piston 32 is displaced against the spring 31 and switched to the clutch engaged state.

  Further, one end of the fifth shaft 26 is supported by the side cover 33 attached to the right side surface of the transmission case 9, and the side cover 33 is equipped with a multi-plate type braking mechanism B that controls the pivot of the ground. ing. The brake mechanism B has a frictional braking action on the fifth shaft 26 by the ring-shaped piston 34 advancing inward of the case by applying hydraulic pressure and pressing and displacing the pressing plate 35 against the internal spring 36. In addition, the application of hydraulic pressure is released and the pressing plate 35 is restored and retracted by the internal spring 36 so that braking is released. The piston 34 is attached to the outer surface of the side cover 33. It is incorporated in block 37.

  FIG. 11 shows a hydraulic circuit diagram and a control system diagram for steering for operating the side clutches 20L and 20R, the clutch C, and the braking mechanism B. In the figure, V1 is a steering switching valve for selectively shifting the side clutch gears 23L, 23R of the side clutches 20L, 20R, and is neutralized by a solenoid SL1 provided outside the transmission case 9. And three forward and reverse positions are selected. V2 is a mode switching valve that selectively supplies pressure oil to either the clutch C or the brake mechanism B to switch the turning mode, and is normally urged to a position for supplying pressure oil to the clutch C. The pressure oil supply position to the braking mechanism B can be switched by a solenoid SL2 provided outside the motor.

  Further, V3 in FIG. 11 is a sequence valve connected to an oil passage d formed in the fourth shaft 19, and its operating pressure is applied to the side clutch gears 23L and 23R of the side clutches 20L and 20R. The pressure is set to shift to the clutch disengagement position and balance with the spring 24. A variable relief valve V4 is connected to the lower side of the sequence valve V3, communicates with a transmission case 9 that also serves as a hydraulic oil tank, and an oil passage branched from between the sequence valve V3 and the variable relief valve V4. e is connected to the primary side of the mode switching valve V2.

  The solenoid SL1 for operating the steering switching valve V1 and the solenoid SL2 for operating the mode switching valve V2 are connected to a steering lever 42 as a steering operating tool provided in the handle tower 41 of the control unit 7 via a control device 43. The variable relief valve V4 is mechanically linked to the steering lever 42.

  As shown in FIG. 12 and FIG. 13, a support shaft 45 is penetratingly attached to a bracket 44 attached to the upper right side (as viewed from the driver) of the handle tower 41 so as to be rotatable around a fulcrum x in the front-rear direction. The steering lever 42 is mounted on a fulcrum bracket 46 connected to the rear end of the support shaft 45 so that the steering lever 42 can swing around the lateral fulcrum y. A first operating arm 47 formed by bending a bar in an L shape protrudes from the fulcrum bracket 46, and a second operating arm 48 made of a plate protrudes from the vicinity of the front end of the support shaft 45. The first operating arm 47 is linked to a potentiometer 49 attached to the handle tower 41 as follows, so that the operating position of the steering lever 42 is electrically detected.

  That is, the operation lever 49a of the potentiometer 49 is urged to rotate clockwise in FIG. 12 by the built-in spring so as to always contact the first operation arm 47 from the side. Is operated in either the left or right direction from the neutral position n, the operation lever 49a rotates following the first operation arm 47 while maintaining the contact state, so that the operation position of the steering lever 42 is adjusted to the potentiometer 49. The output signal is continuously detected as the output change, and the detection signal is input to the control device 43.

  The second operating arm 48 is linked to the release wire 50 for operating the variable relief valve V4 as follows. That is, the support shaft 45 is provided with a pair of operating arms 51 and 52, and both the operating arms 51 and 52 are oscillated and biased in a direction approaching each other by the torsion spring 53 and provided on the bracket 44. The contact is supported so as to sandwich the fixing pin 54. The end of the outer wire 50a of the release wire 50 is connected and supported to the free end of one operating arm 51, and the end of the inner wire 50b of the release wire 50 is connected to the free end of the other operating arm 52. Is supported. Further, an operation pin 48 a provided at the free end portion of the second operation arm 48 that is swung around the fulcrum x in the front-rear direction by the steering lever 42 is installed between the operation arms 51 and 52.

  According to the above configuration, for example, in FIG. 12, when the steering lever 42 is swung from the neutral n to the right turning direction (leftward in the figure), the second operation arm 48 is swung counterclockwise in the figure, The pin 48a contacts and swings one operating arm 51 counterclockwise. At this time, since the other operating arm 52 is prevented from swinging counterclockwise by contact with the fixing pin 54, the inner wire 50b of the release wire 50 is relatively pulled out from the outer wire 50a. Conversely, when the steering lever 42 is swung from the neutral n in the left turning direction (rightward in the figure), the second operation arm 48 is swung in the clockwise direction in the figure, and the operation pin 48a is moved to the other operation arm. 52 is swung in a clockwise direction. At this time, since one operating arm 51 is prevented from swinging clockwise by contact with the fixing pin 54, the inner wire 50b of the release wire 50 is pulled out from the outer wire 50a. That is, even if the steering lever 42 is swung from the neutral n in either the left turning direction or the right turning direction, the inner wire 50b of the release wire 50 is pulled out according to the amount of operation, and the amount of wire drawing is large. It is linked so that the operating pressure of the variable relief valve V4 becomes higher.

  The steering switching valve V1 and the sequence valve V3 are incorporated in the hydraulic block 37, and the mode switching valve V2 and the variable relief valve V4 are incorporated in the side cover 33, and are formed inside the hydraulic block 37 and the side cover 33. The hydraulic circuit shown in FIG. 11 is formed in communication with each other through the oil passage. Hereinafter, the operation structure of the steering switching valve V1, the mode switching valve V2, and the variable relief valve V4 will be described in detail with reference to FIGS.

  As shown in FIGS. 14 to 16, the steering switching valve V 1 is an operation in which a spool 61 slidably mounted in the front-rear direction on the upper part of the hydraulic block 37 is swung from the outside via a support shaft 62. The solenoid SL1 is interlocked and connected to a lever 64 mounted on the outer end of the support shaft 62.

  According to the above configuration, when the steering lever 42 is in the neutral n, the solenoid SL1 is in a non-energized state, the spool 61 is held neutral by the return spring 65, and the pressure oil supplied from the pump port P is drained. It returns to the mission case 9 through the flow path D. When the steering lever 42 is operated in the left turning direction, this is detected by the potentiometer 49, the solenoid SL1 is pushed and driven, and the spool 61 is slid in the left direction in FIG. Oil is supplied to the left-turning side clutch 20L via the oil passage a. Further, when the steering lever 42 is operated in the right turning direction, this is detected by the potentiometer 49, the solenoid SL1 is pulled and driven, and the spool 61 is slid in the right direction in FIG. The pressurized oil is supplied to the right-turning side clutch 20R via the oil passage b.

  As shown in FIGS. 4 and 17, the mode switching valve V2 has an operating arm that swings a spool 66 attached to the upper portion of the side cover 33 so as to be slidable in the front-rear direction from the outside via a support shaft 67. The solenoid SL2 is interlocked and connected to a lever 70 attached to the outer end of the support shaft 67.

  According to this configuration, when the solenoid SL2 is in a non-energized state, the spool 66 is in the position shown in FIG. 17, and the lower oil passage e of the sequence valve V3 is communicated with the oil passage c reaching the clutch C. . When the solenoid SL2 is energized and pulled, the lever 70 swings counterclockwise in FIG. 17, the spool 66 is switched against the spring 69, and the oil passage e reaches the braking mechanism B. It communicates with the oil passage f.

  As shown in FIG. 17, the variable relief valve V 4 includes a poppet 71 that is incorporated in the upper part of the side cover 33 so as to be movable in the front-rear direction, and urges and presses the poppet 71 against the valve seat 72. A spring 73 for blocking communication with the drain flow path D in the path e and a spring receiving member 74 for supporting the rear end of the spring 73 are mounted on the support shaft 67 by external fitting. The relief pressure can be adjusted by sliding and displacing by abutment pressing with an operating arm 76 that is swung from the outside via a cylindrical support shaft 75. An inner wire 50b of the release wire 50 is interlocked and connected to a lever 77 attached to the end. The lever 77 is oscillated and urged by a torsion spring 78 in a direction to move the operating arm 76 away from the spring receiving member 74. As shown in the figure, the operating arm 76 is side cover at the oscillating limit. The relief pressure of the variable relief valve V4 at this time is almost zero. As described above, when the steering lever 42 is swung left and right and the inner wire 50b of the release wire 50 is pulled, the operation arm 76 is swung counterclockwise in FIG. The relief pressure of the variable relief valve V4 is gradually increased as the member 74 is pushed and displaced, and the swinging amount of the steering lever 42 is increased and the wire pulling amount is increased.

  The pre-cutting processing unit 3 is moved up and down by swinging back and forth of the steering lever 42 that can be operated in a cross shape. That is, as shown in FIGS. 12 and 13, on the left and right on the extension line of the lateral fulcrum y, the sensor 81 including a potentiometer or a switch for detecting the forward / backward swing of the steering lever 42 and the steering lever 42 are moved back and forth. A torsion spring 82 for urging the neutral n in the moving direction is provided. When the sensor 81 detects that the steering lever 42 is swung forward from the neutral n, the pre-cutting processing unit 3 is lowered. When the sensor 81 detects that the rocker has been swung backward, the sensor 81 and a drive lifting mechanism (not shown) of the pre-cutting processing unit 3 are linked so as to raise the pre-cutting processing unit 3. Yes.

  Further, reference numeral 83 in FIG. 2 denotes a stop and parking brake arranged to act on the end of the third shaft 13, and by depressing the pedal 84 provided at the foot of the control unit 7, A main clutch (not shown) provided in a transmission system from the engine 6 to the hydrostatic continuously variable transmission 8 is operated to be disengaged, and the brake 83 is operated to be braked. In addition, the parking brake can be applied by holding the pedal 84 in the depressed position.

  The steering apparatus according to the present invention is configured as described above, and the steering operation will be described below.

  When the steering lever 42 is in the neutral position n, the side clutches 20L and 20R are both in a clutch engaged state, the left and right crawler travel devices 1L and 1R are driven at a constant speed, and the airframe travels straight.

  When the steering lever 42 is swung in one of the left and right directions from the neutral n, for example, to the right, this is detected by the potentiometer 49, the solenoid SL1 is energized and the steering switching valve V1 is switched to the right turn position. The pressure oil is supplied through the oil passage b, and the right side clutch 20R is disengaged. In this case, while the steering lever 42 is in the first operating range Rc close to the neutral n, the relief pressure of the relief valve V4 is equal to or lower than the operating pressure of the sequence valve V3, and therefore, the side clutch gear of the side clutch 20R. 23R is displaced only to the clutch disengagement position, the right crawler traveling device 1R is in an idle state, and the body slowly turns rightward by driving only the left crawler traveling device 1L.

  When the steering lever 42 is operated beyond the first operating range Rc to the second operating range Rs, the relief pressure of the leaf valve V4 exceeds the operating pressure of the sequence valve V3. 23R is greatly displaced beyond the clutch disengagement position, and is engaged with the steering side gear 25R as shown in FIG. In this case, while the steering lever 42 is in the second operating range Rs, the solenoid SL2 is in a non-energized state, the pressure oil that has passed through the sequence valve V3 is in a state that can be supplied to the clutch C, and this clutch The hydraulic pressure applied to C is limited by the relief valve V4. Accordingly, the closer the steering lever 42 in the second operation range Rs is to the neutral n side, the lower the hydraulic pressure applied to the clutch C, the smaller the torque transmitted through the clutch C, and the right crawler travel device 1R is on the left side. It is driven at a lower speed and with a smaller torque than the crawler traveling device 1L. The hydraulic pressure applied to the clutch C increases as the steering lever 42 in the second operation range Rs moves away from the neutral n, and the torque transmitted to the right crawler traveling device 1R via the clutch C gradually increases. Finally, the clutch C is completely connected, and the right crawler traveling device 1R is driven at a low speed reduced by a predetermined ratio, and the airframe gradually moves to the right based on the difference in driving speed between the left and right crawler traveling 1R, 1L. Turn around.

  When the steering lever 42 is operated beyond the second operating range Rs to the third operating range Rb, this is detected by the potentiometer 49, the solenoid SL2 is energized and the mode switching valve V2 is switched, and the oil passage e Is connected to the oil passage f and pressure oil is supplied to the braking mechanism B, and the oil passage c is connected to the drain passage D and the clutch C is disengaged. In this case, the relief pressure is already high because the steering lever 42 is greatly operated, so that the fifth shaft 26 is braked by the braking mechanism B, and the right side connected to the fifth shaft 26 is interlocked. While the crawler traveling device 1R is in a braking stopped state, only the left crawler traveling device 1L is driven, and the aircraft suddenly turns rightward (trust turn).

  Needless to say, even when the steering lever 42 is operated in the left turn direction, in the same manner as described above, in the first operation range Lc, a gentle left turn is performed with only the left side clutch 20L disconnected. In the second operation range Ls, the left turn is performed by operating the clutch C to decelerate the left crawler travel device 1L, and in the third operation range Lb, the left crawler travel device 1L is braked. A sharp turn to the left of is made.

  Here, as shown in FIG. 12, the size of the first operation areas Lc, Rc, the second operation areas Ls, Rs, and the third operation areas Lb, Rb is determined by turning off the side clutch inside the turn. The first operating range Lc, Rc that turns only by the thrust of the outer crawler traveling device is the smallest, and the third operating region Lb that turns only by the thrust of the outer crawler traveling device by braking and stopping the crawler traveling device inside the turning. , Rb is the next smallest, and the second operation areas Ls, Rs that are most frequently operated by the crawler traveling device on the inside of the turn that is driven to decelerate and the crawler traveling device on the outside of the turn that is not decelerated are set to be the largest. The second operation areas Ls and Rs correspond to the gentle turning operation area of the present invention.

  The present invention can also be implemented in the following forms.

  (1) As shown in FIG. 18, a spring that is actuated when the steering lever 42 is in the third operating range Lb, Rb and that is compressed by the steering lever 42 as means for imparting resistance to the operation of the steering lever 42. If 85 is provided and the operation resistance increases, and the configuration is made to recognize that the operation area is in the third operation area Lb, Rb, it is possible to avoid inadvertently operating the third operation area Lb, Rb. It becomes easy.

  (2) As shown in FIG. 19, the steering lever 42b can be pivoted by turning the steering handle 42a, so that the steering operation tool 42 can be configured to be rotationally operated.

Right side view of the entire combine Front view showing the transmission structure of the traveling mission case Longitudinal front view showing the upper half of the mission case Longitudinal front view showing the lower half of the mission case Side view showing the operation structure of the sub-transmission mechanism Longitudinal front view of shifter operating the sub-transmission mechanism Longitudinal front view of the main part showing the state where the auxiliary transmission mechanism is switched to low speed Longitudinal front view of the main part showing the sub-transmission mechanism switched to medium speed Longitudinal front view of the main part showing the sub-transmission mechanism switched to neutral Longitudinal front view of essential parts showing the state where the auxiliary transmission mechanism is switched to high speed Diagram of steering hydraulic circuit and control system Front view of the steering operation unit Side view of the steering control unit Side view showing control unit for steering Longitudinal side view showing the periphery of the steering switching valve Front view showing the operation part of the steering switching valve Vertical side view showing the periphery of the mode switching valve and variable relief valve Front view showing another embodiment of the steering operation unit Front view showing still another embodiment of the steering operation unit

Explanation of symbols

1L, 1R Traveling device 20L, 20R Side clutch 42 Steering operation tool 47 Actuating member 49 Potentiometer 49a Operation lever C Clutch Lc, Rc First operation range Ls, Rs Second operation range Lb, Rb Third operation range

Claims (2)

Provided with a pair of left and right crawler type traveling devices, a plurality of operation areas are provided in an operation area from a neutral position of a single steering operation tool to one of the left and right turning directions so that the turning function becomes higher as the distance from the neutral position increases. In the steering device of the formed combine,
The operating range, one of the traveling device on the other of the operating device in the same direction, and includes a slow turning operation region to perform gentle swirling and the deceleration drive at a lower speed than the other of the operating device Rutotomoni, the slow rotation operation range An operation area with higher turning performance than the gentle turning operation area
In the slow turning operation area, the turning performance in the slow turning operation area is set so that the turning function becomes higher as the steering operation tool moves away from the neutral position,
A combine steering apparatus in which an operable range in the gentle turning operation range is set to be larger than other operation ranges among the plurality of operation ranges.   2. The combine steering apparatus according to claim 1, wherein a brake operation area is provided outside the gentle turning operation area.

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