JPS63110030A - Drive mechanism for traveling of agricultural tractor - Google Patents

Abstract

PURPOSE:To make it possible to change a front wheel gear shifter easily through only steering actuation of the front wheel, by providing a controlling mechanism to actuate a drive mechanism automatically based on the information from a sensor and a setting device. CONSTITUTION:A controlling mechanism 23 actuates the first hydraulic piston 12 and the second hydraulic piston 18, using the first control valve 25 and the second control valve 26, based on the information from a steering angle sensor 21 and a setting device 24 for a steering angle of the front wheel for control. After comparing a steering angle alpha detected by a steering angle sensor 21 with the steering angle beta set by a setting device 24, a front wheel gear shifter 6 is maintained in a standard transmission condition if the detected steering angle alpha is found smaller than beta. Conversely, the front wheel gear shifter 6 will be changed over to an accelerating transmission condition if alpha is found more than beta. The setting device 24 is equipped with a manual steering portion 24a so that the set steering angle beta can be changed and adjusted.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a standard in which the average circumferential speed of a pair of left and right steerable front wheels is the same or almost the same as the average circumferential speed of a pair of left and right rear wheels. A drive structure for driving an agricultural tractor provided with a front wheel transmission that can be freely switched between a transmission state and an increased speed transmission state in which the average circumferential speed of a pair of said front wheels is higher than the average circumferential speed of a pair of said rear wheels. Regarding.

[Conventional technology]

The above agricultural tractor maintains the front wheel circumferential speed the same as the rear wheel circumferential speed by switching the front wheel transmission to an increasing speed transmission state and increasing the speed of the front wheels in conjunction with the steering operation of the front wheels. It is constructed so that it can turn with a smaller radius than the

Conventionally, in this type of agricultural tractor, the front wheel transmission can be switched simply by steering the front wheels. The front wheel steering angle was constant when switching from standard transmission state to increased speed transmission state.

[Problem that the invention seeks to solve]

For example, the turning radius that appears when turning by driving the front wheels at increased speed is too small for the weight of the connected working device, and when making a small turn, it affects the working device that is swung around to make the aircraft turn. The centrifugal force becomes extremely large and the aircraft becomes unstable, or the turning radius created by increasing the speed of the front wheels is too large for the weight of the work equipment, resulting in centrifugal force acting on the work equipment when making a small turn. In some cases, the turning radius was not shortened sufficiently from the viewpoint of

An object of the present invention is to enable the front wheel transmission to be switched simply by steering the front wheels, and to easily adjust the front wheel steering angle when the front wheel drive switches to speed increase. It's about doing.

[Means for solving problems]

The characteristic configuration of the present invention is that, in the above-described traveling drive structure for an agricultural tractor, a sensor for detecting the steering angle of the front wheels, a changeable and adjustable setting device for setting the front wheel steering angle for control, and the above-mentioned A drive mechanism for switching the front wheel transmission is provided, and if the steering angle detected by the sensor is smaller than the steering angle set by the setting device, the front wheel transmission is in the standard transmission state, and the sensor automatically operates the drive mechanism based on information from the sensor and the setting device so that when the steering angle detected by the sensor becomes equal to or greater than the steering angle set by the setting device, the front wheel transmission enters the speed increasing transmission state. The operation and effects of the control mechanism are as follows.

[For production]

'When the front wheels are in a steering state where the steering angle is smaller than the set steering angle, the control mechanism automatically operates the drive mechanism based on the information from the sensor and setting device to change the front wheel transmission to standard. When the front wheels are operated to a transmission state and the front wheels are operated to a state where the steering angle is greater than or equal to the set steering angle, the control mechanism automatically operates the drive mechanism based on information from the sensor and setting device. to operate the front wheel transmission to the speed-up transmission state.

When the set steering angle is changed by adjusting the setting device, the control mechanism automatically changes the front wheel transmission when the steering angle of the front wheels reaches the new set angle, which is different from the set angle before the change. Operate the switch.

〔Effect of the invention〕

Due to the action of the control mechanism, the front wheel transmission can be switched simply by steering the front wheels, and the control mechanism operates based on the steering angle set by the setting device.
It is now possible to change and adjust the front wheel steering angle when the front wheels are driven at increased speed with a simple operation.

Therefore, for example, if the traveling speed is constant, the distance traveled while turning from the time the nose wheels begin to be steered until the time when the aircraft switches to the speed increase state and starts turning around is the unit steering angle of the nose wheels. Since the time required for steering operation is almost constant, the larger the front wheel steering angle when the front wheels increase speed, the longer it becomes. The larger the turning radius, the larger the turning radius as a whole.Also, the heavier the connected working device is, the safer it is to increase the turning radius because it reduces the centrifugal force that acts on the working device when turning. Therefore, the front wheel steering angle when the front wheel speed increase is adjusted is adjusted so that the heavier the linkage device is, the larger the steering angle is, and the lighter the linkage device is, the smaller the front wheel steering angle is. No matter how large or small the turning radius is, the shortening of the turning radius by increasing the speed of the front wheels can be utilized as much as possible in consideration of the centrifugal force acting on the working equipment, resulting in advantages such as improved efficiency (and safer work).

〔Example〕

As shown in FIG. 3, a pair of left and right front wheels (1a).

(1b) capable of steering and driving, and a pair of left and right non-steering type rear wheels (2a), (2b) capable of driving. a lift arm (3) that connects the working device so that it can be raised and lowered;
A power take-off shaft (4) for transmitting power to the connected working device is attached to constitute an agricultural tractor.

A front wheel transmission bag W (6) is connected to a mission case (5) forming the rear part of the fuselage, and this front wheel transmission device (6) is constructed as shown in FIG.

In other words, the first output gear of the driving transmission (
The standard transmission gear (8) meshed with 7) and the speed-up transmission gear (10) meshed with the second output gear (9) of the traveling transmission can each be rotated relative to the output shaft (11). An engagement clutch (13) is provided between the standard transmission gear (8) and the first hydraulic piston (12) which is integrally rotatably and slidably attached to the output shaft (11) by spline engagement. , the first hydraulic piston (12) is slidably biased by the spring (14) in a direction away from the standard transmission gear (8), thereby disengaging and biasing the bite clutch (13). A clutch body (15) connected to the speed-increasing transmission gear (10) so as to be integrally rotatable, and an output shaft (
A multi-plate friction clutch (17) is provided between the transmission body (16) which is integrally rotatably attached to the transmission body (11), and this friction clutch (17) is slidably operated toward the transmission body (16). The second hydraulic piston (18) is configured to be operated to enter by a second hydraulic piston (18), and to be biased by a spring (19) that biases the second hydraulic piston (18) away from the transmission body (16). It is.

More specifically, when the first hydraulic piston (12) is slid by the supplied pressure oil and the engagement clutch (13) is operated to engage, the standard transmission gear (8) and the output shaft (11) are connected to the first hydraulic piston. (12), so that the average circumferential speed of the left and right front wheels (1a), (1b) and the average circumferential speed of the left and right rear wheels (2a), (2b) are the same or almost the same. Then, the standard transmission state is established in which the output of the driving transmission is transmitted to the front wheel differential mechanism (20).

Then, when the second hydraulic piston (18) is slid by the supplied pressure oil and the friction clutch (17) is operated to engage, the speed increasing transmission gear (10) and the output shaft (11) rotate by - body. Connected to left and right front wheels (1a).

The average peripheral speed of (1b) is the left and right rear wheels (2a), (2
The vehicle enters a speed-up transmission state in which the output of the traveling transmission is transmitted to the front wheel differential mechanism (20) so that the average circumferential speed becomes higher than the average circumferential speed of b). The first hydraulic piston (12) is slidably operated by the spring (14) to disengage the bite clutch (13), and the second hydraulic piston (18) is slidably operated by the spring (19). When the friction clutch (17) is operated to disengage, relative rotation of both the standard transmission gear (8) and the speed-up transmission gear (10) and the output shaft (11) becomes possible, and the left and right front wheels (1a
) and (1b) are in the idle rotation state, so that the transmission is cut off.

As shown in Fig. 1, a rotary variable resistor type steering wheel detects the leftward and rightward steering angles (α) from the straight-ahead position W (N) of the front wheels (La) and (1b). Angle sensor (
21) is linked to the pitman arm (22) so as to be detected based on the steering angle of the pitman arm (22) and to output the detection result as an electric signal, and to the control mechanism (23). It is a coordination. This system am structure (
23) sets the first steering angle based on the information from the steering angle sensor (21) and the control front wheel steering angle setter (24).
The setting device (24) and the first hydraulic piston (12) and the second hydraulic piston (1) are configured to automatically operate the hydraulic piston (12) and the second hydraulic piston (18).
8) electromagnetically operated first control valve (25) and second control valve (26) for operating each of
The detected steering angle (α) by the steering angle sensor (21) and the set steering angle (α) by the setting device (24) are linked to each other.
The detected steering angle ゛(α) is compared with the set steering angle (β).
), the first control valve (
25) and the second control valve (26), and when it is determined that the detected steering angle (α) is greater than or equal to the set steering angle (β), the front wheel transmission (6) is placed in the speed-up transmission state. The first control valve (25) and the second control valve (26) are configured to be automatically operated so as to switch to the first control valve (25) and the second control valve (26). The setting device (24) is provided with a human operation section (2) so as to be able to change and adjust the set steering angle (β).
4a), simply operate the front wheels (Ia) and (1b) by rotating the steering handle (27) so that the steering angle (α) becomes greater than or equal to the set steering angle (β). The front wheel transmission (6) switches to the speed-increasing transmission state, and the front wheels (1a) and (1b) are driven to increase the speed so that a small turn can be made, and also according to the traveling speed and the weight of the connected work device. When adjusting the turning radius etc., use the setting device (2
4) Just by adjusting the front wheels (1a), (
1b) is configured to be able to change and adjust the front wheel steering angle when switching to the speed-up transmission state.

The control mechanism (23) includes a backward movement sensor (28) that detects backward movement of the aircraft based on the state of the steering transmission;
It is connected to the speed sensor (29) that detects the running speed, and when at least one of high speed information and reverse information indicating that the running speed is higher than the set speed is input, the steering angle sensor (21) It is configured to give priority to the information and stop the switching operation of the front wheel transmission (6) to the speed-up transmission state. In other words, when the aircraft is moving backwards or traveling at a high speed higher than the set speed, even if the front wheels (1a
), (1b) is the steering angle set by the setting device (24) (
For safety reasons, the front wheels are prevented from increasing speed even if the vehicle is steered beyond β).

Reference numeral (30) shown in FIG. 1 is a button-operated control mode selector for switching the control mode by the control mechanism (23). That is, the steering angle sensor (21) and the setting device (2
The front wheel transmission (6) is automatically switched between the standard transmission state and the increased speed transmission state based on the information from 4), in which the front wheel speed can be increased. A four-wheel drive state in which the front wheels cannot speed up is maintained, and a two-wheel drive state in which the front wheel transmission (6) is maintained in a transmission-off state are alternatively brought out.

[Another example]

Figure 2 shows another embodiment of the front wheel transmission (6), in which the clutch body (3) is rotatably attached to the output shaft (11).
1) and the standard transmission gear (8), a multi-plate wet type first friction clutch (32) is provided to be operated by the first hydraulic piston (12), and the clutch body (31)
A second multi-plate wet friction clutch (33) is provided between the transmission gear and the speed increasing transmission gear (10) to be operated by a second hydraulic piston (18). That is, both the standard transmission and the speed-up transmission are configured to be performed by friction transmission.

The front wheel transmission may be implemented by employing a configuration in which the gears are changed by engaging and switching the shift gears. In this case, the shift gear may be configured to be operated by a hydraulic actuator or an electric actuator, and these are collectively referred to as drive mechanisms (12) and (1B).

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of the drawing]

The drawings show an embodiment of the driving structure for an agricultural tractor according to the present invention, in which Fig. 1 is a sectional view of a front wheel transmission, Fig. 2 is a sectional view of a front wheel transmission separately implemented, and Fig. 3 is a sectional view of the entire agricultural tractor. FIG. (1a), (1b) = ...front wheel, (2a)
, (2b)...-rear wheel, (6)...
Front wheel transmission, (12), (18)...drive mechanism, (21)...sensor, (23)...
...control mechanism, (24) ...setting device.

Claims (1)

[Claims] a standard transmission state in which the average peripheral speed of the pair of left and right steerable front wheels (1a), (1b) and the average peripheral speed of the pair of left and right rear wheels (2a), (2b) are the same or almost the same;
A front wheel transmission ( 6
) A drive structure for driving an agricultural tractor, comprising:
A sensor (21) that detects the steering angle of the front wheels (1a) and (1b), a changeable and adjustable setting device (24) that sets the front wheel steering angle for control, and the front wheel transmission (6). drive mechanisms (12) and (18) for switching and operating the front wheel transmission (6), and when the steering angle detected by the sensor (21) is smaller than the steering angle set by the setting device (24), the front wheel transmission (6) ) is in the standard transmission state, and when the steering angle detected by the sensor (21) becomes equal to or greater than the steering angle set by the setting device (24), the front wheel transmission (6) enters the increased speed transmission state. The drive mechanism (
12) A drive structure for driving an agricultural tractor, which is provided with a control mechanism (23) for automatically operating (18).