JPH04118385A - Steering control structure for farm working vehicle - Google Patents

Abstract

PURPOSE:To secure a smooth slow turn by installing a booster controlling mechanism in common with a first hydraulic clutch, transmitting clockwise power, and a second hydraulic clutch, transmitting counterclockwise power, and changing the initial pressure of the booster controlling mechanism corresponding to an operating lever at a neutral position for a pressure rise. CONSTITUTION:A first hydraulic clutch 12 capable of transmitting clockwise power lower speed than the other is installed in one side selected out of a symmetrical pair of travel devices, and a second hydraulic clutch 30 capable of transmitting counterclockwise power in the other side selected out of these paired travel devices, respectively, and a state supplying a hydraulic fluid to these hydraulic clutches 12, 30 and a hydraulic fluid supply for on-operation into the said second hydraulic clutch 30 are controlled for a changeover. In addition, there is provided a booster controlling mechanism 36 in common with both these hydraulic clutches 12, 30, and in response to an operating position of the operating lever 39, it is linked up with this operating lever 39 so as to have on-operating pressure for these first and second hydraulic clutches 12, 30 raised and operated. Moreover, there is provided an operating means 44 which makes the initial pressure of the booster controlling mechanism 36 conformed to the operating lever 39 at a neutral position N alterable for a pressure rise.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a steering operation structure for a working vehicle equipped with a pair of left and right crawler type or multi-wheel type traveling devices.

[Conventional technology]

An example of the above-mentioned work vehicle is a combine harvester equipped with a crawler-type traveling device. In such a combine harvester, a first hydraulic clutch is capable of transmitting normal rotation power at a lower speed than the other to one selected traveling device, and a second hydraulic clutch is capable of transmitting reverse rotation power to one selected traveling device. Some have a clutch. As a result, by driving one traveling device at low speed, it is possible to make gentle turns reliably even on soft ground, and by driving one traveling device in reverse, it is possible to make turns in a small radius. Can do turns.

The switching operation between the gentle turning and the super turning is performed by switching the supply direction of the hydraulic oil for the engagement operation to the first and second hydraulic clutches using a switching valve, and supplying this hydraulic oil to the first hydraulic clutch. This is done depending on whether the hydraulic pressure is supplied to the hydraulic clutch or the second hydraulic clutch. A common pressure-up adjustment mechanism is provided for the first and second hydraulic clutches, and the pressure-up adjustment mechanism is operated by an operation lever to increase the pressure of the hydraulic oil, thereby controlling the first or second hydraulic clutch. Enter and operate.

[Problem to be solved by the invention]

A super pivot turn using the second hydraulic clutch can be performed with a very small radius, so if you perform a super pivot turn from a straight ahead state, the aircraft will be thrown around, which is a safety issue. Undesirable. Therefore, a super turn is often performed after the vehicle has stopped or while the vehicle is running at an extremely low speed.

As a result, if the pressure is set to increase by the pressure increase adjustment mechanism or to increase from 0 pressure in a linear function according to the operating position of the operating lever, the pressure can be changed little by little using the operating lever near 0 pressure. The turning radius of the super turn can be easily adjusted slowly and subtly by slipping the second hydraulic clutch.

On the other hand, since gentle turning using the first hydraulic clutch has a large turning radius, there is no particular problem in making gentle turning from a state where the combine is traveling straight at high speed. If the size is very large, the following problems may occur.

In other words, if the pressure increase characteristic of the pressure increase adjustment mechanism is set to increase from 0 pressure by 1 in a linear function according to the characteristics of the second hydraulic clutch, then the first hydraulic pressure can be adjusted by using the operating lever to perform a slow turn when traveling straight. When attempting to engage and operate the clutch, unless the amount of operation of the operating lever is sufficient, the pressure of the first hydraulic clutch will not be sufficient, and the traveling device on the inside of the turn will stop due to large traveling resistance. Therefore, even if you try to make a smooth slow turn from a straight-ahead state, the moment you slightly operate the control lever, the aircraft will turn at an unexpectedly small radius.

An object of the present invention is to enable a smooth slow turn while retaining the function of finely adjusting the turning radius during a super turn.

[Means to solve the problem]

The feature of the present invention is that the steering operation structure for a working vehicle as described above is configured as follows. That is, (1) [A] A selected one of the traveling devices is provided with a first hydraulic clutch capable of transmitting forward rotational power at a lower speed than that of the other traveling device.

[Port] A second hydraulic clutch capable of transmitting reverse rotation power is provided to a selected one of the traveling devices.

[C] A switching valve is provided that can be switched between a state in which the first hydraulic clutch is entered and the operating oil is supplied, and a state in which the second hydraulic clutch is entered and the operating fluid is supplied.

[2] A common pressure increase adjustment mechanism is provided for the first hydraulic clutch and the second hydraulic clutch.

[e] The operating lever and Links with boost adjustment mechanism.

[f] Operation at the neutral position) An operating means is provided that can increase the initial pressure of the pressure increase adjustment mechanism corresponding to <-.

[G] A hydraulic clutch capable of transmitting forward rotation power or reverse rotation power is provided to a selected one of the traveling devices, separately from a power transmission system for straight-ahead travel.

[H] A transmission mechanism is provided that can be switched between a state in which normal rotation power at a lower speed than the other traveling device is transmitted to the hydraulic clutch and a state in which reverse rotation power is transmitted to the hydraulic clutch.

[S] The hydraulic clarifier is provided with a pressure increase adjustment mechanism.

[J] The operation lever and the pressure increase adjustment mechanism are linked together so that the pressure for the engagement operation of the hydraulic clutch is increased by the pressure increase adjustment mechanism in accordance with the operation position of the operation lever for manual operation. .

[L] Equipped with an operating means that can increase and change the initial pressure of the pressure increase adjustment mechanism corresponding to the operation lever at the neutral position.

[For production]

(i) With the configuration as described in the previous section (■), when the switching valve is operated to the side that supplies hydraulic oil to the second hydraulic clutch (super pivot turning state), the operating means lowers the initial pressure of the boost adjustment mechanism. Just set it.

As a result, as the operating lever is operated from the neutral position, the pressure of the second hydraulic clutch is gradually increased in a linear function. Therefore, the turning radius can be finely adjusted in a corner turn while the second hydraulic clutch is in a half-clutch state and is allowed to slip.

When the switching valve is operated to the side for supplying hydraulic oil to the first hydraulic clutch (slow turning state), the initial pressure of the pressure increase adjustment mechanism may be set high using the operating means.

As a result, when operating the operating lever from the neutral position, the pressure of the first hydraulic clutch will increase from the high initial pressure mentioned above, so when starting to operate the operating lever from the neutral position, The problem is that the pressure at which the hydraulic clutch is fully engaged is quickly reached.

Therefore, if the operating lever is operated while the vehicle is traveling straight, the first hydraulic clutch for slow turning is quickly engaged, and one of the traveling devices is driven at a low speed, and the vehicle smoothly transitions to slow turning.

(ii) With the configuration as described in the previous item (■), if the hydraulic clutch is engaged and operated while the transmission mechanism is operated to transmit low-speed forward rotation power, one of the traveling gears will be driven forward at low speed and the aircraft will rotate. Make a slow turn. Conversely, if the hydraulic clutch is engaged and operated while the transmission mechanism is being operated to transmit reverse power, one side of the traveling gear will be driven in the reverse direction, allowing a super turning turn to be performed.

Therefore, by changing the initial pressure of the boost adjustment mechanism according to the switching state of the transmission mechanism, it is possible to finely adjust the turning radius in a super turn, as well as to make a smooth transition to a slow turn, as described above. .

〔Effect of the invention〕

As described above, by changing the initial pressure of the pressure increase adjustment mechanism, the pressure increase adjustment mechanism retains the function of finely adjusting the turning radius during a super turn. Alternatively, it became possible to quickly engage and operate the dual-purpose hydraulic clutch to smoothly transition to a slow turn, thereby improving the steering performance of the work vehicle.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

Figure 2 shows the structure inside the transmission case (8) of the traveling system of a combine harvester, which is one of the working vehicles.
A hydrostatic continuously variable transmission (not shown) is transmitted via a belt transmission mechanism (not shown) with a tension clutch.
1), the power is transmitted from the output shaft (3) of the hydrostatic continuously variable transmission (1) to the J transmission shaft (4), and the one-way clutch (5). It is transmitted to the reaping section (6) shown in FIG. 5 via the output turnip-J-(7).

The power from the first transmission shaft (4) is transmitted to the first gear (9) and the second transmission shaft.
The power is transmitted to the second transmission shaft (11) via the gear (10), and the second transmission shaft (11) has a shaft gear (14) with a spline structure and a slidable outer bottom. A high speed gear (6) and a low speed gear (17) are fixed to the third transmission shaft (15).

With the above structure, by sliding the shift gear (14) and engaging it with the high speed gear (16) or the low speed gear (17), the power can be shifted into two stages, high and low, and this power is transferred to the low speed gear (I7). ) engages with the third gear (I
9).

On the support shaft (20) that supports the third gear (I9), the right side gear (21R) and the left side gears 1 to 2 (L) are fitted on the outside so as to be relatively rotatable, and the left and right axles (22L) (
It is always engaged with the input gears (23R) and (23L) of the left and right sight gears (22R) and (21L) and (21R).

This allows the right or left side gear (21R), (2)
, L) relative to the third gear (19) for occlusion/
A crawler-type traveling device (24
) performs important power transmission operations to the drive sprocket (24a), and the site clutch (
25R), (25L).

Next, a structure for applying braking to one axle (22R) or (22L) will be explained. As shown in Fig. 2, the right fourth gear (26R) and the left fourth gear (26R) are attached to the support shaft (20).
A pair of fifth gears (29) are supported by bearings so as to be relatively rotatable, and are fixed to a fourth transmission shaft (27).
It engages with the right fourth gear (26R) and the left fourth gear (26L). A multi-plate hydraulically operated side brake (28) is provided at one end of the fourth transmission shaft (27). As a result, the right side gear (21R) or left side gear (21L) is separated from the third gear (19) and engaged with the right fourth gear (26R) or left fourth gear (26L), and the hand brake (28) is activated. Braking can be applied to one of the axles (22R) or (22L) by engaging the vehicle. And this is a pivot situation.

Next, a structure for reversing one axle (22R) or (22L) will be explained. As shown in Fig. 2, the sixth gear (3G) meshes with the high speed gear (1G) of the third transmission shaft (I5).
7) is externally fitted on the fourth transmission shaft (27) so as to be relatively rotatable, and a second hydraulic clutch (30) is provided between the sixth gear (37) and the fourth transmission shaft (2γ). There is. As a result, the right side gear (21R) or the left side gear (21R)
L) is engaged with the right fourth gear (26R) or the left fourth gear (26L) as described above, and the second hydraulic clutch (
30), the power from the high-speed gear (I6) is in reverse, and the speed is reduced to 1/2 (axle <22R).
Or it is transmitted to (22L). And this is a state of super confidence turning.

Next, a structure for driving one axle (22R) or (22L) in normal rotation at a lower speed than the other will be described.

As shown in Fig. 2, the first sprocket (13) is fixed to the third transmission shaft (I5), and the fourth transmission shaft (27)
A second sprocket (38) is fitted around the sprocket so as to be relatively rotatable, and a transmission chain (40) is wound around the first and second sprockets (13) and (38). A first hydraulic clutch (12) is provided between the second sprocket (38) and the fourth power transmission shaft (27). This allows the right or left side gear (21R).

(21L) to the right or left 4th gear (26R), (26L)
), when the first hydraulic clutch (12) is engaged and operated, the forward rotational power from the third transmission shaft (15) or 17
2 and is transmitted to the axle (22R) or (22L). And this is a slow turning state.

Next, hydraulic cylinders (31R), (31L), which slide the left and right side gears (21L), (21R),
Handbrake (28), first and second hydraulic clutches (
The hydraulic oil supply structure to 12) and (30) will be explained. As shown in Fig. 1, the hydraulic oil from the pump (32) is transferred to the left and right side gears (21L
), hydraulic cylinder (31R) for (21R),
(31L) and the hydraulic cylinder (31R).
), oil passage (34) from the side of (31L), handbrake (28), first and second hydraulic clutches (12)
, (30) is connected to a second switching valve (35) (corresponding to a switching valve). Further, the oil passage (34) includes a hand brake (28), first and second hydraulic clutches (1
2), Variable IJ IJ-F valve (36) for (30)
) (equivalent to a boost adjustment mechanism) is connected.

Next, the operations of the first switching valve (33), the second switching valve (35), and the variable relief valve (36) will be explained. As shown in Figure 1, the operating lever (39) and the variable relief valve (3
6) or wire (41) and variable relief valve (36)
The operating lever (39) and the first switching valve (33
) are mechanically linked. In addition, variable relief valve (
36) is provided with a second operating arm (43) in addition to the first operating arm (42), and also includes a second switching lever (44) (corresponding to operating means) and a second operating arm (42).
43) and wires (45). A first switching lever (18) is provided for operating the second switching valve (35).

The state shown in Fig. 1 is the state in which the first switching lever (18) is operated to the pivot position, and the hydraulic oil is supplied to the second switching valve (35) or the handbrake (28) (35a).
) is being operated on. In this state, when the operating lever (39) is operated from the neutral position (N) to the first right turning position (R3) or the first left turning position (Ll), only the first switching valve (33) is operated and the hydraulic pressure is Cylinder (31
Right or left operation part (46R) by R) or (31L)
, (46L) and the right or left side gear (21R) which was engaged with the third gear (19).

(21L) is separated from the third gear (19) and engages with the right or left fourth gear (26R), (26L).

In this case, the variable relief valve (36) is fully open and the hand brake (28) is off, so power transmission to the right or left axle (22R), (22L) is cut off (side The clutch (25R) or (25L) is disengaged), and the aircraft slowly turns to the right or left. In addition, a sequence valve (
47) is the right or left side gear (21R), (21L
) fully engages the right or left fourth gear (26R), (26L) using the hydraulic cylinder (31R).
, (31L).

Next, move the operating lever (39) to the right or left first turning position (R,
), (L, ) to the right or left second turning position (R2),
(L2), the right or left side gear (21
R).

(21L) is the right or left 4th gear (26R), (26L)
) and is operated to the position (35a) where hydraulic oil is supplied to the second switching valve (35) or the handbrake (28), the pulling action of the wire (41) and the first operating arm ( 42), the variable relief valve (
36) It is gradually operated from the fully open state to the closed side. As a result, the handbrake (28) begins to act, and the right or left axle (22R) or (22L) is gradually braked, and the aircraft turns to the right or left. Then, the operating lever (39) is moved to the right or left second turning position (R2
), (L2), the braking force of the handbrake (28) becomes maximum.

Next, when the first switching lever (18) is operated to the super turning position, the second switching valve (35) or the second hydraulic clutch (30
) is switched to the hydraulic oil supply position (35b).

In this state, when the operating lever (39) is operated from the neutral position (N) to the right or left first turning position (R,), (L,), the right or left side clutch (25R) is activated as described above.
(25L) appears in the cut state.

When the first switching lever (18) is operated to the super turning position, the second switching lever (44) should be operated to the lowest position as shown in Fig. 1 (initial pressure or O situation). Then, move the operating lever (39) to the right or left first turning position (R
,), from (L,) to the right or left second turning position (R2),
(L2), the right or left side gear (2
1R), (21L) or right or left 4th gear (26R),
(26L), and the supply position (35b) of hydraulic oil to the second switching valve (35) or the second hydraulic clutch (30).
), the variable relief valve (
36) is gradually operated from the fully open state (corresponding to the state where the initial pressure is 0) to the closed side. The operating lever (39) between the two rotation positions (R2) and (L2)
) and the pressure of the second hydraulic clutch (30) are as shown by the solid line (A2) in FIG.

As a result, the second
By changing the degree of engagement of the hydraulic clutch (30), the turning radius of the super pivot turn is finely adjusted.

Next, when the first switching lever (I8) is switched to the slow rotation position, the second switching valve (35) or the first hydraulic clutch (]2)
The hydraulic oil supply position (35c) is operated. In this case, operate the second switching lever (l14) to the high side and use the second operating arm (43) to control the variable relief valve (3).
6) to the closed side (initial pressure is increased). In this case, if the operating lever (39) is in the neutral position (N), the first switching valve (33) is in the neutral position and the sequence valve (47) is closed, so the first hydraulic clutch (12) is in the neutral position.
) is O (see solid line (A1) in Figure 3).

In the above state, when the operating lever (39) is operated from the neutral position (N) to the right or left first turning position (R1), (L,), the first switching valve (33) is operated and the hydraulic cylinder (3
Right or left side gear (21) by (1R) or (31L)
R), (21L) is operated by sliding. During this time, the sequence valve (47), which is almost engaged with the right or left side gear (21R), (21L) or the right or left fourth gear (26R), (26L), is closed, so the first hydraulic clutch ( 12) The pressure does not increase. Then, the sequence valve (
47) is opened, the variable relief valve (36) is closed to some extent, as shown by the solid line (A1) in Figure 3.
The pressure of the first hydraulic clutch (12) increases rapidly. As a result, the first hydraulic clutch (12) is in a half-clutch state or in an engaged state, and a gentle turn can be performed without delay.

When the second switching lever (44) is used to increase the initial pressure as described above, flexibility occurs between the first operating lever (42) on the operating lever (39) side and the variable relief valve (36). , as shown by the solid line (A1) in FIG.
) to the right or left second turning position (R2), (L2 side), a situation occurs where the pressure does not increase.

After this flexibility disappears, the pressure in the first hydraulic clutch (12) increases depending on the operating position of the operating lever (39). Further, it is possible to change and adjust the degree of closing of the variable relief valve (36) (change and adjust the initial pressure) by operating the second switching lever (44) depending on the ground condition.

As shown in FIG. 4, first and second switching levers (18),
(44) are arranged in parallel, and a protrusion (18a) is fixed to the first switching lever (18). As a result, when the first switching lever (18) is operated to the super pivot position, the protrusion (
18a) comes into contact with the second switching lever (44), so that the second switching lever (44) is forcibly operated to the lowest position.

[Another example]

A structure as shown in FIG. 6 may be used. That is, a fixed support shaft (55) is provided in the mission case (8), and the seventh gear pair (56) externally fitted on this support shaft (55) is connected to the sixth gear pair (56).
While engaging the gear (37), the seventh gear pair (56)
A shift member (57) is provided which can engage and lock and fix the shift member. A shift member (58) is attached to the third transmission shaft (15) with a spline structure, and a position where the shift member (58) is engaged with the sixth gear (37);
The position where the 7th gear pair (56) engages, the 6th gear (37
) and the 7th gear pair (56) in the neutral position.
It is configured so that it can be slid into position. In this case, the handbrake (28), first and second sprockets (13), (38) and first hydraulic clutch (12) shown in FIG.
) etc. are omitted.

The first switching lever (18) shown in FIG. 1 is mechanically linked to the two sets of shift members (57) and (58). The two sets of shift members (57) and (58) are linked so that they are in the state shown in FIG. Then, a second operating arm (
43) and a second switching lever (44).

It should be noted that the present invention is not limited to the structure shown in the accompanying drawings by adding reference numerals in the claims for convenient comparison with the drawings.

[Brief explanation of drawings]

The drawings show an embodiment of the steering operation structure for a working vehicle according to the present invention, FIG. 1 is a diagram showing the state of connection of the second switching valve and the first and second hydraulic clutches, and FIG. 2 is a longitudinal section of the transmission case. A front view, FIG. 3 is a diagram showing the relationship between the pressure of the first and second hydraulic clutches and the operating position of the operating lever, FIG. 4 is a plan view showing the arrangement of the first and second switching levers, and FIG. 5 is a side view of the front half of the combine harvester, FIG. 6 is a schematic front view of a transmission case in another embodiment, and FIG. 7 is a relationship between the first switching lever and the operating positions of two sets of shift members in another embodiment. It is a diagram. (12)...First hydraulic clutch, (24)...
...Traveling device, (30)...Second hydraulic clutch (hydraulic clutch), (35)...Switching valve, (
36)... Pressure increase adjustment mechanism, (39)... Operation lever, (44)... Operation means, (N)...
- Neutral position.

Claims (1)

[Claims] 1. A steering operation structure for a work vehicle equipped with a pair of left and right traveling devices (24), (24), comprising the configurations described in [A] to [F] below. Steering operation structure of a certain work vehicle. [B] A first hydraulic clutch (12) capable of transmitting normal rotational power at a lower speed than the other traveling device (24), (24) to the selected one of the traveling devices (24), (24). )
Equipped with [B] A second hydraulic clutch (30) capable of transmitting reverse rotation power is provided to a selected one of the traveling devices (24), (24). [C] A state in which the first hydraulic clutch (12) is entered and hydraulic oil for operation is supplied, and the second hydraulic clutch (30)
A switching valve (35) is provided that can be switched between the state of supplying hydraulic oil for operation and the state of supplying hydraulic oil for operation. [d] A common pressure increase adjustment mechanism (36) is provided for the first hydraulic clutch (12) and the second hydraulic clutch (30). [E] The pressure for engaging the first or second hydraulic clutch (12), (30) is adjusted by the pressure increase adjustment mechanism (36) in accordance with the operating position of the manual operating lever (39). the operating lever (39) so that the
and the pressure increase adjustment mechanism (36). [F] An operation means (44) is provided that can increase the initial pressure of the pressure increase adjustment mechanism (36) corresponding to the operation lever (39) at the neutral position (N). 2. Steering operation structure for a work vehicle equipped with a pair of left and right traveling devices (24), (24), which is equipped with the configuration described in [Tool] to [Toru] below. Operation structure. [G] A selected one of the traveling devices (24), (24) is provided with a hydraulic clutch (30) capable of transmitting forward rotation power or reverse rotation power, separately from the power transmission system for straight travel. [H] The other traveling device (2) is connected to the hydraulic clutch (30).
4) A transmission mechanism is provided that can be switched between a state of transmitting forward rotational power at a lower speed than that of (24) and a state of transmitting reverse rotational power to the hydraulic clutch (30). [Li] The hydraulic clutch (30) is provided with a pressure increase adjustment mechanism (36). [J] The pressure for engaging the hydraulic clutch (30) is increased by the pressure increase adjustment mechanism (36) in accordance with the operating position of the manual operation lever (39). Operation lever (39) and boost adjustment mechanism (36)
link. [L] An operation means (44) is provided that can increase the initial pressure of the pressure increase adjustment mechanism (36) corresponding to the operation lever (39) at the neutral position (N).