JPS6076475A - Control arrangement for agricultural tractor - Google Patents

Abstract

PURPOSE:To make it possible to drive front wheels even if a failure in an electrical system occures, by providing a solenoid valve which may selectively change over a control section between an accelerating transmitting position and a transmission stopping position. CONSTITUTION:By means of a branch transmission system having a speed change gear 10 which may be changed over among a condition in which an output from a counter speed change gear is transmitted for acceleration, a condition in which the output is transmitted for running at a uniform or substantially uniform speed, and a condition in which the transmission is stopped, the output from the counter speed change gear 8 is transmitted speed-changeably and stoppingably to a front wheel differential gear mechanism 11. Both left and right front wheels 1a, 1b are arranged such that the operation of the front wheels 1a, 1b may be made changed over among an accelerating drive condition in which the averaged speed of both front wheels 1a, 1b is higher than the averaged speed of both left and right rear wheels 2a, 2b, a uniform speed drive condition in which the averaged spees of the front and rear wheels 1a, 1b, 2a, 2b are equal or substantially equal together and an idle condition.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a pair of left and right front wheels that can be steered freely, a steering mechanism that separately drives and stops a pair of left and right rear wheels, and a steering mechanism that separately drives and stops the pair of left and right rear wheels. A speed increasing transmission state in which the peripheral speed is transmitted to a state where the peripheral speed is greater than the average peripheral speed of the rear wheels, and transmission is transmitted to the both front wheels in a state where the average peripheral speed thereof and the average peripheral speed of the rear wheels are the same. Constant velocity transmission state,
Further, a transmission device is provided that can suddenly switch to a state where power transmission to only the front wheels is stopped, and an operating section of the transmission device is configured to be operated by a pair of electromagnetic solenoids, so that the transmission to the rear wheels is controlled during work. In addition, the front wheels can also be driven to reliably prevent slips while driving, and when turning at the edge of a field, the front wheels can be driven at increased speed in conjunction with front wheel steering and operation to stop driving the rear wheel on the inside of the turn. Regarding the operating structure of an agricultural tractor that is configured to be able to make a quick (small) IC turn and also to be able to drive safely on the road with the front wheels in a non-driven state, conventionally, in the above agricultural tractor, the aforementioned operating section It is configured to bias the transmission to the transmission stop position and to switch to the speed-up transmission position and constant-speed transmission position separately by a pair of solenoids, so that one of the solenoids is always switched and operating during work. Since it is necessary to maintain the current in the energized state, especially the solenoid that sets the operating part to the constant velocity transmission position, it is necessary to keep the energization in the energized state for a long time, which increases the power consumption and Seizure and damage to the solenoid were more likely to occur.

In addition, when a failure occurs in the electrical system, front wheel drive may become disabled and the vehicle may slip easily, making work difficult.

An object of the present invention is to save power, effectively avoid damage to the solenoid, and further enable front wheel drive even if an electrical system failure occurs.

In order to achieve the object, the present invention provides an operation structure for an agricultural tractor as described above, in which the operation section is biased to a constant velocity transmission position, and both electromagnetic solenoids are used to force the operation section to a speed-up transmission position and a transmission stop position. It is characterized by a solenoid that switches to each position separately.

In other words, in consideration of the fact that agricultural tractors are generally driven for work longer than they are driven on the road, the transmission is set to a constant speed drive state or a transmission disengaged state with both solenoids in the disengaged state. I made it switch to .

The constant speed drive state that should be achieved during normal work driving, which is the longest of the rolling, road driving, and small MA#) turning driving and normal work driving, can be obtained with both solenoids turned off. It is.

Therefore, the time it takes to energize the solenoid is shorter than when driving on the road! This can be done in a relatively short time only when turning the S-shape, saving more power than before, and making it difficult for the solenoid to seize and break. What's more, even when the electrical system fails and the sononoid operation becomes impossible, the transmission can be maintained at a constant speed and the front wheels can be driven, making work more efficient from a driving standpoint.

Below, embodiments of the present invention will be explained based on the drawings.As shown in Figure 1, a pair of left and right front steering axles (1 m)
, (lb) and drive rear wheels (8 m), (gb), and a lift arm (3) for connecting various work devices such as a rotary tiller (not shown) to the rear of the traveling machine so that it can be raised and lowered. , and a second power take-off shaft (4) that transmits power to the connected working device to constitute an agricultural tractor.

As shown in Figure 2, the output of the engine (5) is transmitted to the rear wheel differential mechanism (9) via the main clutch (6), main transmission (7), and auxiliary transmission (8). , rear wheel (8a)
, (1), and can suddenly switch the input from the sub-transmission device (8) to a state of increasing speed transmission, a state of transmitting at constant speed or almost constant speed, and a state of transmission stop. The auxiliary transmission [
(8) is configured to transmit the output from the front wheel differential mechanism (11) to the front wheel differential mechanism (11) so as to be able to change speed and stop freely.
, (lb), the average circumferential speed of this is the left and right rear wheels (Bm), (
gb), the front and rear wheels (1 m) are in an increased speed driving state where the average circumferential speed is greater than the average circumferential speed of the wheel.

(lb), (g), and CBb) have the same average circumferential speed, and are configured so that they can be suddenly switched between a constant speed drive state and an idle state, which are almost the same, by the transmission.

The transmission device (to) is constructed as follows.

In other words, as shown in Fig. 8, the gear (1) that rotates integrally with the input shaft (0) is attached to the gear (9), and the speed increasing gear (9) is connected to the output shaft (1).
+5) so that it can rotate freely relative to the speed increasing gear O.
The hydraulic piston o, which is biased towards the clutch disengagement side, switches between the pre-speed transmission state in which → rotates integrally with the output shaft α and the transmission disengaged state in which it rotates relative to the output shaft (11). The on/off operation is freely provided by the speed increasing gear (141) and the output shaft (+5). A reduction unit consisting of an interlocking planetary gear 1, a sun gear (a) etc. which is attached to the output shaft (1@) so as to be integrally rotatable in a state where the planetary gear (lf4) is engaged with the planetary gear 1, and the like is provided. Output shaft 05) in the occlusal state
Fix or unfix the gear unit η, which is attached so that it can rotate freely relative to
A hydraulic piston biased towards the brake release side allows for easy on/off operation. Then, by engaging the speed-increasing clutch H and setting the constant-velocity brake to gJ, the system enters a speed-increasing transmission state, and by disengaging the speed-increasing clutch, the constant-velocity brake is turned on. By doing this, the constant velocity transmission state is not maintained, and when both latches are turned off, the transmission becomes even better when both latches (2) are turned off.

Then, as shown in FIG. 4, both the pistons O'6
, fil / The control valve is configured to be operated by an individual control valve, which is energized to the constant velocity transmission position, and the control valve is configured to be operated by the control valve to the increased speed transmission position and the transmission position. A pair of electromagnetic solenoids (25 m), (tab
), these solenoids (15m), (B5b)
The gear shift operation is performed by turning on and off.

As shown in the MfIg diagram, +17 wheels (la), (lb)
A switch as a steering operation detection mechanism for detecting whether the steering angle of the steering wheel is greater than or equal to the setting is configured in the interlocking system between the power steering cylinder (b) and the front wheels (1m) and (lb). A pair of steering brakes (29a), which are attached to detect based on the swing angle of the member (c), are also used to drive and stop the left and right rear wheels (ga), (2b) and direct the rear wheels. ), (g9b) as a steering brake operation state detection mechanism for detecting whether or not only one of the brakes (jl!9m) is being operated.
), (99b) are operated separately.
+ (Blb) K these (81si).

(81b) is attached so as to detect based on whether or not only one of the gears is in the depressing position, and the sub-transmission device (8) capable of shifting to multiple gears is not in the highest speed state for driving on the road. The switch (2) for detecting whether f! As shown in FIG.
Control mechanism for the solenoid (25a) and (tab) (
It is linked to (goods). And this control mechanism (goods)
When the sub-transmission device (8) is on the low speed side, that is, up to 8th speed, and the steering angle of the front wheels (1m), (lb) is greater than the setting, the left and right rear wheels (Bm), (Jb) In order to automatically switch the transmission ((b) to the speed-increasing transmission state only when only one of the two is in the drive stop state, each detection switch (-1@
Both solenoids F (85m), (25m) based on information from
b) is configured to be automatically operated. 'moreover,
The control mechanism (to) has a manual operation switch (to) for this purpose.
) is attached, and this switch (to) is placed in the first operating position (A).
UT), the solenoids (25a) and (25b
) is in the front wheel automatic gear shift control state where the control mechanism (to) is automatically operated, and the switch (to) is set to the 8th operating position If
(DT), each detection switch (to), -1 (to)
Both solenoids (85a), regardless of the information from
When the control mechanism (to) is turned off to the four-wheel drive state where (tab) is maintained in the OFF position, each detection switch is -9
Regardless of the information from (to), the solenoid (tab
) is configured so that the control mechanism (to) enters the two-wheel drive state where it is maintained in the input position.

In summer, in detail, the switch (to) is turned on, the front and rear wheels (1
The vehicle can be switched between a four-wheel drive state in which both the rear wheels (gm), (lb), (gm), and (gb) are driven, and a two-wheel drive state in which only the rear wheels (gm) and (gb) are driven. Furthermore, by setting the switch (to) to the first operating position (AUT) and setting the sub-transmission device (10) to one of the first to eighth speeds, the front wheels (la) can be adjusted.

(1b) is steered beyond the set angle, and either one of the rear wheels (2a) or (2) corresponds to the inner side of the turn.
b) Just by driving and stopping the front wheels (1, a).

(1b) is self-supporting and the front wheels (la) and (lb
) and also steers the inner rear wheel (2a) or (2b
) All you have to do is stop the aircraft.

In addition, as shown in FIG. 5, the control mechanism includes the switches 11, a, □) and a solenoid (25 m),
(25b) are connected through a resistor, a diode, and a transistor.

The lamp (to) shown in the figure is a pilot lamp that lights up to indicate that the automatic gear shift control for the front wheels (1 m) and (lb) is on.

The steering brakes (29s+) and (29b) can be changed to steering clutches, and these are connected to the left and right rear wheels (2a).
, (8b) respectively.
They are collectively referred to as a) and (29b).

The transmission (10) may be configured to be switched by an electromagnetic clutch, and the controller (1 reel pargoux) is referred to as an operation section (e).

The present invention can also be applied to a case where the transmission (10) is configured to be manually switched by operating switches on both solenoids.

[Brief explanation of the drawing]

The drawings show an embodiment of the operating structure of the agricultural tractor according to the present invention, in which Fig. 1 is a side view of the agent tractor, Fig. 2 is a transmission system diagram, Fig. 8 is a sectional view of the transmission, and Fig. 4. is a control system diagram, and FIG. 5 is an Asahi circuit diagram. (la), (lb) =------front wheel, (Ja)
, (2b) "'"'Rear wheel, (lO)...
・Transmission device, shift control...operation section, (25a). (25b)... Electromagnetic solenoid, -...
・Steering masterpiece angle detection mechanism, (29a), (29b)...
... Steering mechanism, -... Steering mechanism operation state detection mechanism.

Claims (1)

[Scope of Claims] ■ A pair of left and right front wheels (1m), (lb) are provided so as to be freely steerable, and a pair of left and right driven rear wheels (jl!a), (2b) are provided.
) Steering mechanism (29m) that drives and stops each motor separately. (29b), and a speed increasing transmission state in which transmission is transmitted to both the front wheels (1 m) and (lb) such that their average circumferential speed is greater than the average circumferential speed of the rear wheel; (la
), (lb) are these average circumferential speeds and the said rear wheel (
Ja), (gb) have the same average speed, and the front wheels (1 m), (lb
) A transmission device (lO) that can be freely switched to a state where transmission is stopped for only
The operation structure of the agricultural tractor is configured to be operated by the user, and the operation part is biased to a constant velocity transmission position, and the electromagnetic solenoids (25a) and (25b)
is a solenoid that separately switches the operating portion between a speed-up transmission position and a transmission stop position. (2) A mechanism in which both the electromagnetic solenoids ('25a) and (25b) detect the steering angle of the front wheels (1m) and (lb), and the steering mechanism (1?9a), (2
The operating structure according to claim 0, wherein the mechanism for detecting the operating state of (9b) is a solenoid that is automatically operated based on information from each of the mechanisms.