JPH10138945A - Steering device for speed difference steering working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively constitute a steering device of a combine which can select a plurality of turn states. SOLUTION: This device has a first selector valve 50 for selecting either a slow turn clutch 12 or a side brake 28, a second selector valve 51 for selecting either the side brake 28 or a reverse clutch 30, a third selector valve 51 for selecting either the first selector valve 50 or the second selector valve 51, a detector switch 53 for detecting a steering lever 39 being forcibly pressed to the left or the right, and a controller 45 which is changed from the slow turn to a brake turn by pressing the steering lever 39 when the third selector valve 52 is at a first turn mode position (e) and which is changed from the brake turn to a super pivot turn by pressing the steering lever 39 when the third selector valve 52 is at a second turn mode position (f).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work machine such as a combine equipped with a crawler traveling device or a transport vehicle equipped with a multi-wheel drive traveling device, that is, a difference in speed between left and right traveling devices. The present invention relates to a steering device for a speed-difference steering type working machine that is turned.

[0002]

2. Description of the Related Art This type of working machine is disclosed in Japanese Unexamined Patent Publication No. Hei 5-3455.
No. 76 or Japanese Unexamined Patent Publication No. 7-47973 discloses that a turning state is produced by tilting a steering operation tool to the left and right. It has been possible to select between a turning state, a pivot turning state or a brake turning state, that is, a sharp turning state.

[0003]

When the steering operation tool is further tilted from the normal turning operation position in the gentle turning state, the operation is automatically switched to the sharp turning state, and when the operating tool is returned, the original gentle turning state is restored. The structure of returning to the turning state was adopted. This is a technology that aims to improve the steering operability by matching the psychology of the human operation custom that wants to further tilt and operate the steering operation tool when "I want to make a further turn" It is.

In order to selectively use the slow turning state, the brake turning state, and the super turning state, the latter publication uses a three-position switching type solenoid valve, so that the operation structure is expensive. In addition, the switching operation of the turning state by mode selection is performed by electric control, so the gentle turning state is selected due to a failure that can not be recognized beforehand such as impact on the control device or radio wave interference. However, there is a problem that the inconvenience such as the appearance of a turning point of a super-radix when the steering operation is performed cannot be eliminated. The present invention
It is an object of the present invention to make it possible to select a plurality of types of turning states at a low cost, and to enhance reliability by ensuring that the set turning state appears.

[0005]

[Means for Solving the Problems]

[Structure] A first invention provides a pair of left and right traveling devices, a low-speed driving mechanism capable of driving one of these traveling devices in the same direction at a driving speed lower than the other driving speed, and one of the traveling devices. A slow brake state in which one of the two traveling devices is driven in the same direction at a lower speed than the other; and Drive one of the
A speed difference steering type work capable of displaying a brake turning state in which the other is braked and a super turning state in which one of the two traveling devices is driven to rotate forward and the other is driven to rotate reversely. A first switching valve for selecting one of a gentle turning state and a brake turning state, and a second switching for selecting one of a brake turning state and a super turning state, A single steering operation tool having a valve, a neutral position and a turning position, and pressurization detection capable of detecting that the steering operation device has been pressurized from the turning position in a direction opposite to the neutral position Means for turning the steering operation tool from the neutral position to the turning position, a slow turning state appears, and the first switching valve is operated by the pressurizing operation to switch from the slow turning state to the brake turning state. The first switching valve and the pressure detecting means are linked so as to be replaced. The first turning mode, and the operation of the steering operating tool from the neutral position to the turning position causes the brake turning state to appear, and the second switching valve is operated by the pressurizing operation to change from the brake turning state to the pivot turn. A mode switching means for selectively selecting and setting any one of a second turning mode in which the two switching valves and the pressurization detecting means are linked to each other so as to switch to the state. The third switching valve is characterized in that it can be switched between a state in which only the first switching valve can supply hydraulic oil and a state in which only the second switching valve can supply hydraulic oil.

A second invention provides a pair of left and right traveling devices, a low-speed drive mechanism capable of driving one of these traveling devices in the same direction at a driving speed lower than the other driving speed, and one of the traveling devices. A slow brake state in which one of the two traveling devices is driven in the same direction at a lower speed than the other; and One of the two traveling devices is driven forward, and the other is driven in reverse, and a super turning state is realized. In a steering device of a speed difference steering type working machine, a turning selection valve for selecting any one of a gentle turning state, a brake turning state, and a pivot turn state is provided with two input ports. And three output ports And a two-position switching valve configured to reciprocally switch between supply of hydraulic oil and discharge of hydraulic oil to two input ports, and mode detection means for detecting an operation position of the two-position switching valve. A single steering operation tool having a neutral position and a turning position, and pressure detecting means capable of detecting that the steering operation tool has been pressed from the turning position in a direction opposite to the neutral position. In the state in which the two-position switching valve is operated to the one switching position, a gentle turning state appears by the operation of the steering operation tool from the neutral position to the turning position, and from the gentle turning state by the pressurizing operation. In a state where the first turning mode for switching to the brake turning state appears and the two-position switching valve is operated to the other switching position, the steering operation tool is operated from the neutral position to the turning position by the operation. The brake turning state appears, And turning control means for linking the two-position switching valve and the turning selection valve so that the second turning mode in which the turning operation is switched from the brake turning state to the pivot turning state by the pressurizing operation appears. Is a characteristic configuration.

According to a third aspect of the present invention, there is provided a pair of left and right traveling devices, a low-speed driving mechanism capable of driving one of the traveling devices in the same direction at a driving speed lower than the other driving speed, and one of the traveling devices. A slow brake state in which one of the two traveling devices is driven in the same direction at a lower speed than the other; and One of the two traveling devices is driven forward, and the other is driven in reverse, and a super turning state is realized. In a steering device for a speed difference steering type work machine, a first switching valve for selecting one of a gentle turning state and a brake turning state, and a second switching valve capable of supplying pressure oil only to the first switching valve. One position,
A second switching valve that can be switched to any of a second position in which a pivot turn state appears, a single steering operation tool having a neutral position and a rotation position, and Pressure increasing means for increasing the pressure of the supply oil to the second switching valve when further moving from the turning position to the neutral position.
When the supply pressure to this is low, it is maintained at a position where a gentle turning state appears, and when the supply pressure is high, the pilot switching valve is forcibly switched to a position where a brake turning state appears. In the state in which the switching valve is switched to the first position, a gentle turning state appears by operating the steering operation tool from the neutral position to the turning position, and a slow turning state is switched from the slow turning state to the brake turning state by the moving operation. In the state in which the 1-turn mode is displayed and the second switching valve is switched to the second position, the turning operation of the steering operation tool from the neutral position to the turning position and the turning operation of the pivoting position regardless of the moving operation are performed. Is configured to appear in a third turning mode in which is displayed.

According to the first aspect of the present invention, when the steering operation tool is operated to the turning position in a state where the first turning mode is selected by operating the third switching valve as the mode switching means, the pressure is increased. Oil operates the low-speed drive mechanism through the first switching valve, and a gentle turning state appears. When the steering operation tool is further pressed to move the steering operation tool, the pressure detection means operates to switch the first switching valve, and pressure oil is sent to the side brake to automatically switch to the brake turning state. Instead (see FIG. 4).

Next, when the steering operation tool is operated to the turning position in a state where the second switching mode is selected by operating the third switching valve, pressure oil is supplied to the side brake through the second switching valve. Thus, the brake turning state appears (see FIG. 5). When the steering operation tool is further pressed to move the steering operation tool, the pressure detecting means is operated to switch the second switching valve, and the pressure oil is sent to the reversing mechanism to automatically turn the super pivot point. (See FIG. 6).

In other words, the inexpensive two of the first to third switching valves.
With the three position switching valves, the same function as that of the conventional means using the solenoid valve having the three-position switching structure can be exhibited, so that the automatic turning to the sharp turning state is performed by pressing the steering operation tool from the turning operation position. The structure for this can be configured at a low cost, while being able to be switched in a timely manner.

According to the second aspect of the present invention, the first turning mode in which the steering operation tool is switched from the gentle turning state to the brake turning state by pressing operation from the turning position, and the brake turning state is changed to the super pivot turning state. When the second turning mode to be switched is made to appear using the turning selection valve of the three-position switching valve, a two-position switching valve is added and controlled. In other words, a state in which one of the operation position for the gentle turning state and the operation position for the brake turning state is selected, and a state in which the operation position for the brake turning state and the operation position for the super turning state are selected Can be separated by a two-position switching valve, so that, due to some kind of failure, the turning selection valve is switched to the operating position for the super pivot turning state when the first turning mode is selected, or Even if the turning selection valve is switched to the operation position for the slow turning state when the two turning mode is selected, the malfunction does not occur even if an erroneous operation occurs.

For example, in the first turning mode state shown in FIG. 9, even if the turning selection valve 62 is switched to the operation position g for the pivot turn state, the supply of the pressurized oil is prevented by the internal structure of the turning selection valve 62. Thus, the reversing mechanism 30 is restrained so as not to operate. Also, in the second turning mode state shown in FIG. 11, even if the turning selection valve 62 is switched to the operation position i for the gentle turning state, the supply of the pressure oil is prevented by the internal structure of the turning selection valve 62, and the low-speed drive mechanism is provided. It is checked so that 12 does not operate.

According to the third aspect of the invention, the following operations are provided. In the above-described second turning mode, when the steering operation tool is operated to the turning operation position, the super pivot turning state appears immediately so that the quick turning operation can be performed quickly. This is because the second turning mode is selected when the soil can be easily turned sharply from the beginning, such as when the soil of the field is hard or headland.

Thus, when selecting the second swing mode by operating the second switching valve, it is sufficient to configure only the state where the pressure oil operates the reverse rotation mechanism. Can be omitted. Then, when the first switching mode is selected by operating the second switching valve, first, the first switching valve is in the operation position for the gentle turning state, and when the steering operation tool is further moved from the turning position, The first switching valve is automatically switched by the increase of the circuit pressure (pilot pressure) due to this, and the brake turning state appears. Therefore, a turning operation structure can be realized with two two-position switching valves, and it is not necessary to use either valve as an electromagnetic valve, so that a turning operation system can be configured at low cost.

[Effect] In the speed difference steering type working machine according to the first aspect, selection of the relatively large turning first turning mode and the relatively small turning second turning mode, and the turning operation position of the steering operation tool are performed. Thus, it is possible to provide a steering device that can be configured in an inexpensive state by using three two-position switching valves for each operation structure of automatic switching of the swirling mode by the pressurizing operation.

According to the second aspect of the present invention, there is provided a speed-difference-steering working machine, wherein a relatively large turning first turning mode and a relatively small turning second turning mode are selected, and the turning operation of the steering operation tool from the turning operation position is performed. Although each operation structure of the automatic switching of the turning mode by the pressure operation is configured to be controlled using the three-position switching valve, it is possible to prevent an unintended turning state even if an unexpected control failure occurs. As a result, the turning state of the street was surely revealed, and the steering device was excellent in reliability.

In the speed difference steering type working machine according to the third aspect of the present invention, the vehicle is braked from a gentle turning state with the operation of the steering operating tool by a simple idea of fixing the steering mode in the super turning state. Switching between a first turning mode that is automatically switched to a turning state and a third turning mode that is only a super pivot turning state,
In addition, the steering apparatus can be provided in which the automatic switching of the turning mode in the first turning mode can be configured in an inexpensive state with two 2-position switching valves other than the solenoid valve.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a threshing device 5 is mounted on a body supported by a pair of left and right traveling devices 24 of a crawler type, and a mowing unit 18 is supported at a front part of the body.
A combine as an example of a work vehicle is configured. FIG. 2 shows the structure inside the transmission case 8 of the combine, in which power from an engine (not shown) is transmitted via a belt transmission mechanism (not shown) having a tension clutch to a hydrostatic continuously variable transmission. 1 is transmitted to the input pulley 2, and the power from the output shaft 3 of the hydrostatic continuously variable transmission 1 is transmitted to the reaper 18 at the front of the machine body shown in FIG. 1 via the first transmission shaft 4.

The power from the first transmission shaft 4 is transmitted to the second transmission shaft 11 via the first gear 9 and the second gear 10.
A shift gear 14 is slidably fitted on the second transmission shaft 11 in a spline structure, and a high-speed gear 16, a medium-speed gear 17, and a low-speed gear 6 are fixed to the third transmission shaft 15. . With the above structure, the shift gear 14 is slid, and is engaged with the high-speed gear 7, the medium-speed gear 17 or the low-speed gear 6 that meshes with the high-speed gear 16 to shift the forward rotation power for straight traveling into three stages of high, medium and low. This forward rotation power is transmitted to the first transmission gear 19 that meshes with the middle speed gear 17. As described above, the gear shift type transmission 13 is constituted by the shift gear 14, the high-speed gear 7, and the like.

A right side gear 21R and a left side gear 21L are rotatably fitted on a support shaft 20 supporting the first transmission gear 19, and input gears 23 of left and right axles 22 are connected to the left and right side gears 21R, 21R. 21L is always engaged. Thereby, the right or left side gear 21R, 2R
1L is slid with respect to the first transmission gear 19 to engage and disengage, thereby performing power transmission and transmission cutoff operations to the crawler type traveling device 24.
And the left and right side gears 21R, 21L form side clutches 25R, 25L.

Next, a description will be given of a structure in which one of the traveling devices 24 is rotated in the reverse direction to perform a pivot turn. As shown in FIG. 2, a third gear 37 meshing with the high-speed gear 16 of the third transmission shaft 15 is fitted around the fourth transmission shaft 27 so as to be relatively rotatable.
A reverse clutch 30 between the gear 37 and the fourth transmission shaft 27;
(Corresponding to a reverse rotation mechanism) is provided. Second transmission gears 26R and 26L are supported by bearings on both left and right ends of the support shaft 20, and each of the fourth transmission gears 29 fixed to both ends of the fourth transmission shaft 27 is engaged with the second transmission gears 26R and 26L. doing.

Thus, the right side gear 21R or the left side gear 21L is connected to the right or left second transmission gear 26.
When the reverse rotation clutch 30 is engaged while being engaged with R and 26L, the power from the high speed gear 16 is transmitted to one traveling device 24 in the reverse rotation state and reduced to 1/3. In this case, the other side gears 21R and 21L mesh with the first transmission gear 19 and are driven to rotate forward.
The airframe makes a super-revolution turn.

Next, a description will be given of a structure in which braking is applied to one of the traveling devices 24 to perform a pivot turn. As shown in FIG. 2, a multi-plate type side brake 28 (corresponding to a braking mechanism) is provided between one end of the fourth transmission shaft 27 and the transmission case 8. Thereby, the right side gear 21R or the left side gear 21L is connected to the right or left second transmission gear 2.
When the side brake 28 is turned on while being engaged with the 6R and 26L, one of the traveling devices 24 is braked.
In this case, the other side gears 21R and 21L are meshed with the first transmission gear 19 and are driven to rotate forward, so that the airframe makes a pivot turn.

Next, a structure in which one of the traveling devices 24 rotates forward at a lower speed than the other to make a gentle turn will be described. As shown in FIG. 2, a small-diameter output gear 38 is fixed to the boss portion of the first transmission gear 19, and a large-diameter third transmission gear 40 is fitted to the fourth transmission shaft 27 so as to be relatively rotatable. The third transmission gear 40 is engaged with the output gear 38. Then, the gentle turning clutch 12 is disposed between the third transmission gear 40 and the fourth transmission shaft 27.
(Corresponding to low-speed driving means).

As a result, the right or left side gear 21
When the gentle turning clutch 12 is engaged with the R and 21L engaged with the right or left second transmission gears 26R and 26L, the straight forward power transmitted to the first transmission gear 19 is output to the output gear 38. Through the third transmission gear 40, the gentle turning clutch 12, the fourth transmission shaft 27, the fourth transmission gear 29, and the right or left second transmission gear 26R, 26L, as forward power reduced to 1/3. It is transmitted to one traveling device 24. In this case, the other side gears 21R and 21L are engaged with the first transmission gear 19 and are driven to rotate forward at a predetermined speed, so that the aircraft slowly turns due to the speed difference between the left and right traveling devices 24.

Next, a structure for supplying hydraulic oil to the hydraulic cylinders 31R, 31L for performing the sliding operation of the left and right side gears 21R, 21L, the gentle turning clutch 12, the side brake 28 and the reverse rotation clutch 30 will be described. As shown in FIG. 3, the hydraulic oil from the pump 32 is supplied to the hydraulic cylinders 31R, 31L for the left and right side gears 21R, 21L via the steering switching valve 33, and from the side of the hydraulic cylinders 31R, 31L. The oil passage 34 is provided with a steering valve mechanism C that supplies pressure to any one of the gentle turning clutch 12, the side brake 28, and the reverse rotation clutch 30.

The steering valve mechanism C has two positions including a gentle turning position a for supplying hydraulic oil to the gentle turning clutch 12 and a brake turning (radial turning) position b for supplying hydraulic oil to the side brake 28. A two-position switching electromagnetic type including a switching electromagnetic type first switching valve 50, a brake turning position c for supplying hydraulic oil to the side brake 28, and a super pivot position d for supplying hydraulic oil to the reverse clutch 30. The second switching valve 51 and the first
A two-position switching mechanically operated third switching valve 52 having a first position e for supplying pressure oil only to the switching valve 50 and a second position f for supplying pressure oil only to the second switching valve 51. ing.

In parallel with the third switching valve 52, an electromagnetically operated on-off valve 43 and a relief valve 44 for the gentle turning clutch 12 are provided.
And a variable relief valve 36 for the side brake 28 and the reverse rotation clutch 30 is connected in series to the on-off valve 43. A steering lever 39 (corresponding to a steering operation tool) capable of swinging left and right is supported by the steering section of the fuselage, and the steering lever 39 is connected to the steering switching valve 33 and the variable relief valve 36 by a wire. Linkage mechanisms 41, 4 comprising
Linked by two.

As shown in FIG. 3, the steering lever 39 is in the neutral position N, the right and left first turning positions R1 and L1, the right and left second turning positions R2 and L2, and the right and left third turning positions. Position R
It can be freely operated at 7 positions, 3 and L3. Third turning position R
3 and L3 are set to slight operation amounts from the second turning positions R2 and L2, and the steering lever 39 is moved to the third turning position R.
3, a limit switch (an example of the pressure detecting means D) 53 that is turned ON only when operated to L3 (see FIG. 8).
, The on-off valve 43 and the first and second switching valves 50 and 51 are connected to the control device 45. Further, a lever for switching the third switching valve 52 is provided as a mode switching lever 54. When the third switching valve 52 is operated to the second position f, the first switching valve 50 is operated in conjunction therewith. A mechanical linking mechanism 55 is provided for forcibly switching from the gentle turning position a to the brake turning position b independently of the operation of the solenoid 50a. Next, a steering operation state by operating the steering lever 39 will be described.

When the mode switching lever 54 is operated to the first turning mode position A. When the steering lever 39 is at the neutral position N, the steering switching valve 33
Is also operated to the neutral position and the left and right hydraulic cylinders 31R, 31
L contracts, and the left and right side gears 21R, 21L
The transmission gear 19 is engaged. As a result, the forward power transmitted to the first transmission gear 19 is transmitted to the left and right traveling devices 24.
, The left and right traveling devices 24 are driven at the same speed, and the aircraft is traveling straight.

When the steering lever 39 is operated from the neutral position N to the left or right first turning position L1 or R1, the steering switching valve 33 is operated and the left or right operating section 46 is operated by the hydraulic cylinder 31L or 31R. Through the first transmission gear 19
Left or right side gear 21L, 21R engaged with
Are engaged with the left or right second transmission gears 26L, 26R while being separated from the first transmission gear 19.

In this case, the state in which the pressure can be supplied to the gentle turning clutch 12 by the steering valve mechanism C has appeared, but since the variable relief valve 36 is substantially fully opened, the gentle turning clutch 1
2 is in the disengaged state, and the transmission to the left or right traveling device 24 is interrupted (the side clutch 25L or 25L).
(The R-cut state), and the aircraft gradually changes its direction to the left or right (hereinafter, this state is referred to as a single-drive turning state). The sequence valve 47 provided in the oil passage 34 controls the pressure required for the left or right side gear 21L, 21R to completely mesh with the left or right second transmission gear 26L, 26R by a hydraulic cylinder. This is for securing at 31L and 31R.

Next, the steering lever 39 is moved from the left or right first turning position L1, R1 to the left or right second turning position L2.
When operated to R2, the control device 45 closes the on-off valve 43 with the left or right side gears 21L, 21R engaged with the left or right second transmission gears 26L, 26R in the state shown in FIG. You. Thereby, the oil passage 34
, The gentle turning clutch 12 is quickly engaged, the left or right traveling device 24 is driven forward at a low speed, and the aircraft slowly turns left or right. In this case, the left or right second turning position L2, R of the steering lever 39
2, the variable relief valve 36 is operated to the closing side by the action of the linkage mechanism 42. However, since the on-off valve 43 is closed, the variable relief valve 36 acts on the gentle turning clutch 12. I haven't.

When the steering lever 39 is further pressed and tilted from the left or right second turning position L2, R2 to the left or right third turning position L3, R3, the limit switch switch 53 is turned on. Then, the control device 45 functions so that the first switching valve 50 is forcibly switched from the gentle turning position a to the brake turning position b based on this, and the opening / closing valve 43 is operated to the open position. Further, by operating the steering lever 39 to the left or right second turning position L2, R2, the variable relief valve 36 has already been operated to the closed side by the action of the linkage mechanism 42.

Accordingly, the left or right side gear 21L or 21R is engaged with the left or right second transmission gear 26L or 26R, and as shown in FIG. 4, the third switching valve 52 is moved to the first position e.
In addition, the first switching valve 50 is at the brake turning position b, and the variable relief valve 36 is operated to the closed side, and the side brake 28 acts to apply braking to the left or right traveling device 24. The aircraft then brakes left or right. Then, when the pressing operation of the steering lever 39 is stopped, a return spring (not shown) returns to the left or right second turning position L2, R2, and the limit switch 53 is turned off so as to return to a gentle turning state. .

When the mode switching lever 54 is operated to the second turning mode position B, as shown in FIG. 5, when the mode switching lever 54 is operated to the second turning mode position B, the third switching valve 52 is set to the second turning mode position. At the same time as switching to the position f, the first switching valve 50 is switched to the brake turning position b by the action of the mechanical linkage mechanism 55,
A check is made so that oil is not discharged from the side brake 28 via the first switching valve 50.

In this state, when the steering lever 39 is operated to the neutral position N, the aircraft advances straight as described above, and when the steering lever 39 is operated to the left or right first turning position L1 or R1, this is also performed as described above. The right side clutches 25L and 25R are disengaged and perform one-drive turning to the left or right. Then, when the steering lever 39 is operated to the left or right second turning position L2 or R2, the pressure in the oil passage 34 sharply increases as described above, the side brake 28 is operated, and the left or right traveling device 24 Braking is applied, and the aircraft turns left or right.

When the steering lever 39 is further pressed and tilted from the left or right second turning position L2 or R2 to the left or right third turning position L3 or R3, the limit switch 53 is turned on. Then, as shown in FIG. 6, the control device 45 functions so as to switch the second switching valve 51 from the brake turning position c to the super turning position d while the on-off valve 43 is operated to the open position. At this time, the link mechanism 42
Has already operated the variable relief valve 36 to the closed side.

Accordingly, the left or right side gear 21L, 2
1R is engaged with the left or right second transmission gear 26L, 26R, the third switching valve 52 is at the second position f, the second switching valve 51 is at the super pivot position d, and is variable. Since the relief valve 36 is in the closed state, the reverse rotation clutch 3
When 0 is activated, the reverse power is transmitted to the left or right steering device 24, and the aircraft turns left or right. Then, when the pressing operation of the steering lever 39 is stopped, the return spring (not shown) returns to the left or right second turning position L2, R2, and the limit switch 53 is turned off to control to return to the brake turning state. .

For reference, FIG. 7 shows a change chart of the lever operation amount and the turning state in each turning mode. Next, the operation structure of the steering lever 39 will be described.

The basic operation structure of the steering lever 39 and the first and second linkage mechanisms 41 and 42 is well known (Japanese Patent Laid-Open No. 5-34).
No. 5576), but in the present application, some ingenuity has been taken. That is, as shown in FIG. 8, a pair of arms 56 and 57 that swing freely around the horizontal axis P1 is pivotally supported by a steering lever 39 that can swing about the horizontal axis P1. The outer wire 42a of the first arm 5
6 and the inner wire 42b is connected to the other arm 57.
Connected to each other. Further, a pin 58 fixed to the lower end of the steering lever 39 is disposed so as to enter between the pair of arms 56 and 57, and a first pin made of a push-pull wire is provided.
The inner wire 41b of the link mechanism 41 is connected to the pin 58.

The two tension type first and second extension types are extended over the extension portions 56a and 57a fixed to the arms 56 and 57, respectively.
Second springs 59 and 60 are installed, and both arms 5
A stopper pin 61 having a fixed position is disposed between the stopper pins 6 and 57. The first spring 59 has a relatively low spring constant, and always biases the extension portions 56a, 57a closer to bias the steering lever 39 to the neutral position N. Second spring 6
Numeral 0 has a relatively large spring constant, and the locking portions 60a, 60a at both ends are normally in a free state, and do not act on both the extension portions 56a, 57a.

The second spring 60 is set so as to be pulled only when the steering lever 39 is operated to the left or right second turning position L2 or more than the second turning position L2.
When the levers exceed the second turning positions L2 and R2 in order to operate the levers 3 and R3, the lever operation force acts as soon as possible. Thus, the operator can recognize that the turning form changes according to the lever operation feeling.

[Another Embodiment] —Part 1— As shown in FIG. 9, a three-position, five-connection electromagnetic turning selector valve 62 having two input ports and three output ports.
And a mechanically operated two-position switching valve 63 that reciprocally switches between supply of hydraulic oil and discharge of hydraulic oil to the two input ports of the swing selection valve 62, and constitutes a steering valve mechanism C. In addition, the configuration other than having the mode detecting means 64 for detecting the operation position of the two-position switching valve 63 and having the turning control means 65 in the control device 45 is different from that of the present embodiment shown in FIG. Basically the same.

As shown in FIG. 13, the mode detecting means 64
Is constituted by a limit switch 66 that operates when the mode switching lever 54 is operated to the second turning mode position B. Reference numeral 67 denotes an operation wire for interlocking the two-position switching valve 63 and the mode switching lever 54. In the free state, the turning selection valve 62 is maintained at the center position h.

First, when the mode switching lever 54 is operated to the first turning mode position A, the two-position switching valve 63 is at the forward position j, and the steering lever 39 is shifted from the neutral position N to the first turning position L1, The slow turning state appears by the operation to R1. When the steering lever 39 is operated to the second turning positions L2 and R2, the circuit pressure increases, and in the state shown in FIG. 9, the pressure oil is supplied to the gentle turning clutch 12 to enter a gentle turning state. At the third turning positions L3 and R3, the limit switch 53 is turned off, and the first turning mode detection of the limit switch 66 causes the turning control means 65 to move the turning selection valve 62 from the center position h as shown in FIG. The control is switched to the right position i, the pressure oil is supplied to the side brake 28, and the brake turning state appears.

Next, when the mode switching lever 54 is operated to the first turning mode position B, the two-position switching valve 63 is in the reverse position k, and the steering lever 39 is shifted from the neutral position N to the first turning position L1. , R1 causes a gentle turning state to appear. When the steering lever 39 is operated to the second turning position L2, R2, the circuit pressure increases, and the pressure oil is supplied to the side brake 28 in the state of FIG. Third
Limit switch 53 is OFF at turning positions L3 and R3
As the limit switch 66 detects the second turning mode, as shown in FIG.
5 controls the turning selection valve 62 to switch from the center position h to the left position g, and pressurized oil is supplied to the reverse rotation clutch 30 so that the super pivot turning state appears.

In this means, the turning selection valve 62 is selected in a state where the first turning mode is selected due to an electric trouble or the like.
May be erroneously operated to the left position g, or the slewing selection valve 62 may be erroneously operated to the right position i in the state in which the second slewing mode is selected. The vehicle will be blocked, and a check is made to prevent an unexpected turning state from appearing.

By the way, as shown in FIG. 14, a mode switch 64 may be provided by providing a limit switch 66 for detecting the movement of the operated arm 63a to which the operation wire 67 is connected in the two-position switching valve 63. .

-Part 2- As shown in FIG. 15, a first switching valve 69 for selecting either a gentle turning state or a brake turning state, and pressure oil can be supplied only to the first switching valve 69 The second switching valve 70, which can be switched between a first position q and a second position r at which the super pivot turning state appears, and the steering lever 39 are moved to the second turning position L
2, a variable relief valve (an example of a pressure increasing means) 36 for increasing the pressure of the supply oil to the second switching valve when the operation of moving from the R2 position to the third turning position L3, R3 is provided. That is, the first switching valve 69 and the second switching valve 70 constitute the steering valve mechanism C.

The first switching valve 69 is maintained at the right position n where a gentle turning state appears when the supply pressure to the first switching valve 69 is lower than a predetermined pressure, and when the supply pressure is higher than the predetermined pressure, the brake turning state is established. The pilot-operated switching valve is forcibly switched to the left position m in which is displayed. That is, the predetermined pressure means that the steering lever 39 is moved from the second turning position L2, R2 to the third turning position L.
3, the pressure is set to appear in the oil passage 34 during the movement operation to R3.

When the mode switching lever 54 is operated to the first turning mode position A, the second switching valve 70 is in the forward position q, and the steering lever 39 is shifted from the neutral position N to the first turning positions L1, R1. A gentle turning state appears by the operation of. When the steering lever 39 is operated to the second turning position L2, R2, the circuit pressure increases, and the pressure oil is gradually reduced in the state shown in FIG.
2 to be in a gentle turning state. Third turning position L3
At R3, the pilot pressure becomes higher than the predetermined pressure, the first switching valve 69 is forcibly switched to the left position m, and the pressure oil is supplied to the side brake 28, whereby the brake turning state appears.

When the mode switching lever 54 is operated to the first turning mode position B, the second switching valve 70 is at the reverse position r, and the steering lever 39 moves from the neutral position N to the first turning positions L1 and R1. A gentle turning state appears by the operation of. When the steering lever 39 is operated to the second turning position L2, R2, the circuit pressure increases, and the hydraulic oil is supplied to the reverse rotation clutch 30, and the super pivot turning state appears. In this case, the steering valve mechanism C does not change even if the third turning position L3 or R3 is operated from there, and the super turning state is maintained.

That is, in the state where the second switching valve is switched to the first position, the gentle turning state appears by operating the steering operating tool from the neutral position to the turning position, and the moving operation causes the slow turning state to appear. In a state in which a first turning mode for switching to a brake turning state appears and the second switching valve is switched to the second position, an operation of the steering operation tool from the neutral position to the turning position, and It is configured such that a third turning mode in which the super pivot turning state appears regardless of the moving operation.

In this embodiment, a pressure switch D is provided by providing a limit switch 68 which is operated by the movement of an operated arm (not shown) of the variable relief valve 36, and the switching operation of the on-off valve 43 is controlled by the detection operation. It is a judgment standard.

The "pressing operation" includes the state in which the steering lever 39 is actually moved as in the embodiment, and the state in which the pressure is not actually moved but the pressure is literally pressed to operate the pressure-sensitive switch. Shall be included.

[Brief description of the drawings]

FIG. 1 is an overall side view of a combine.

FIG. 2 is a schematic diagram showing a transmission structure in a transmission case.

FIG. 3 is a system diagram showing a steering control device.

FIG. 4 is a hydraulic circuit of a main part showing a third turning state in the first turning mode.

FIG. 5 is an essential hydraulic circuit showing a second turning state in the second turning mode.

FIG. 6 is an essential hydraulic circuit showing a third turning state in the second turning mode.

FIG. 7 is a relationship diagram between a steering lever position and a turning state.

FIG. 8 is a side view showing the operation structure of the steering lever.

FIG. 9 is a system diagram showing a first alternative structure of the steering control device;

10 is an essential hydraulic circuit showing a third turning state of the first turning mode in the structure of FIG. 9;

11 is a main part hydraulic circuit showing a second turning state of the second turning mode in the structure of FIG. 9;

12 is a main part hydraulic circuit showing a third turning state of the second turning mode in the structure of FIG. 9;

FIG. 13 is a diagram showing a first alternative structure of the mode switching detection means.

FIG. 14 is a diagram showing a second alternative structure of the mode switching detection means.

FIG. 15 is a system diagram showing a second alternative structure of the steering control device;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 Low-speed drive mechanism 24 Traveling device 28 Side brake 30 Reverse rotation mechanism 36 Boost means 39 Steering operation tool 50 1st switching valve 51 2nd switching valve 52 3rd switching valve 54 Mode switching means 62 Turning selection valve 63 2-position switching valve 64 Mode detecting means 65 Turning control means 69 First switching valve 70 Second switching valve D Pressurizing detecting means

Claims (3)

[Claims] 1. A pair of left and right traveling devices, a low-speed driving mechanism capable of driving one of these traveling devices in the same direction at a driving speed lower than the other driving speed, and acting on one of the traveling devices. Provided with a possible side brake and a reversing mechanism for reversely driving one of the traveling devices,
A slow turning state in which one of the two traveling devices is driven in the same direction at a lower speed than the other, a brake turning state in which one of the two traveling devices is driven and the other is braked, A steering device for a speed difference steering type working machine, wherein one of the two is driven forward and the other is driven in a reverse direction, and a super turning position is provided. And a second switching valve for selecting one of the brake turning state and the super pivot turning state.
A switching valve, a single steering operation tool having a neutral position and a turning position, and it is possible to detect that the steering operation tool has been pressed from the turning position in a direction opposite to the neutral position. A pressurizing detecting means, respectively, wherein the gentle turning state appears by operating the steering operating tool from the neutral position to the turning position, and the first switching valve is operated by the pressurizing operation. A first turning mode in which the first switching valve and the pressurization detecting means are linked so as to switch from the gentle turning state to the brake turning state; and from the neutral position to the turning position of the steering operation tool. The second switching valve and the second switching valve are operated such that the brake turning state is brought out by the operation of and the second switching valve is operated by the pressurizing operation to switch from the brake turning state to the super pivot turning state. Connect with pressure detection means The second to
And a mode switching means capable of selectively setting one of a turning mode and a mode in which the mode switching means can supply pressure oil only to the first switching valve; and the second switching valve A steering device for a speed differential steering type working machine, comprising a third switching valve capable of selectively changing a state in which pressure oil can be supplied only to the third switching valve. 2. A pair of left and right traveling devices, a low-speed driving mechanism capable of driving one of these traveling devices in the same direction at a driving speed lower than the other driving speed, and acting on one of the traveling devices. Provided with a possible side brake and a reversing mechanism for reversely driving one of the traveling devices,
A slow turning state in which one of the two traveling devices is driven in the same direction at a lower speed than the other, a brake turning state in which one of the two traveling devices is driven and the other is braked, A steering device for a speed difference steering type working machine, wherein one of the two is driven forward and the other is driven in a reverse direction, and a super turning position is provided. And a turn selection valve for selecting any one of the brake turning state and the super turning state in a three-position five connection structure having two input ports and three output ports. A two-position switching valve that reciprocally switches between supply of hydraulic oil and discharge of hydraulic oil to the two input ports, mode detection means for detecting an operation position of the two-position switching valve, a neutral position and a turning position. A single steering operating device with In the state in which the implement is provided with pressure detecting means capable of detecting that the press operation has been performed in the opposite direction to the neutral position from the turning position, the two-position switching valve is operated to one of the switching positions. The first turning mode in which the gentle turning state appears by the operation of the steering operation tool from the neutral position to the turning position, and the braking operation is switched from the gentle turning state to the brake turning state by the pressurizing operation. When the two-position switching valve is operated to the other switching position so as to appear, the brake turning state appears by operating the steering operating tool from the neutral position to the turning position. And
And turning control means for linking the two-position switching valve and the turning selection valve so that a second turning mode in which the brake turning state is switched to the super pivot turning state by the pressurizing operation appears. A steering device for a speed-difference-type working machine, comprising: 3. A pair of left and right traveling devices, a low-speed driving mechanism capable of driving one of these traveling devices in the same direction at a driving speed lower than the other driving speed, and acting on one of the traveling devices. Provided with a possible side brake and a reversing mechanism for reversely driving one of the traveling devices,
A slow turning state in which one of the two traveling devices is driven in the same direction at a lower speed than the other, a brake turning state in which one of the two traveling devices is driven and the other is braked, A steering device for a speed difference steering type working machine, wherein one of the two is driven forward and the other is driven in a reverse direction, and a super turning position is provided. And a first switching valve for selecting one of the brake turning state, a first position at which pressure oil can be supplied only to the first switching valve, and a second position at which the super pivot turning state appears. A second switching valve that can be switched to any position, a single steering operation tool having a neutral position and a turning position, and moving the steering operation tool from the turning position to a direction opposite to the neutral position. A pressure increasing means for increasing the pressure of the supply oil to the second switching valve when the moving operation is further performed, The first switching valve is maintained at a position where the gentle turning state appears when the supply pressure to the first switching valve is low, and is forcibly switched to a position where the brake turning state appears when the supply pressure is high. In a state in which the second switching valve is switched to the first position, the slow turning state appears by operating the steering operation tool from the neutral position to the turning position. In addition, a first turning mode in which the slow turning state is switched to the brake turning state by the moving operation appears, and in a state where the second switching valve is switched to the second position, the steering operation tool is turned on. Speed difference steering configured to cause a third turning mode in which the super pivot turning state appears regardless of the operation from the neutral position to the turning position and the moving operation. Steering device for work machines.