JPH0889019A - Turning control device for tractor - Google Patents

Abstract

(57) [Abstract] [Object] The present invention relates to a turning control device for a tractor, and an auto lift control for raising and lowering a working machine by unexpectedly turning a steering handle in a rough place such as a headland,
The automatic brake control for braking the rear wheel one-side brake device is prevented from accidentally operating. [Structure] An autolift mechanism or a tractor with an autobreak mechanism is provided with a tilt sensor mounted on a machine body, and an autolift or an autobreak is detected based on the detection result of the tilt sensor. A control means is provided for changing the timing and the presence / absence of linkage of the key.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turning control device for a tractor, which is intended to facilitate the turning operation of the machine body at the edge of the ridge and to reduce the mental and physical burden on the operator. is there.

[0002]

2. Description of the Related Art Conventionally, when a steering wheel is turned and operated at a predetermined angle or more, a lift arm is automatically rotated, or a structure is interlocked so that a brake on the inside of a rear wheel is effective. Alternatively, there was an interlocking structure in which these were operated simultaneously.

[0003]

By the way, in such a conventional device, the steering handle and the control valve for raising the lift arm are mechanically interlocked,
Alternatively, since the steering wheel and the rear wheel one-side brake device are mechanically interlocked with each other, if the steering wheel is rotated by a predetermined angle, the working machine automatically operates even when it is not desired to raise the lift arm. Even when the vehicle rises or the brake is not desired to be applied, the brake on the inside of the turning is applied to the rear wheel, and the rear wheel is injured.

In particular, on a ridge or a headland, since many irregularities are generated due to raising and lowering of the working machine, the wheels often fall into a concave portion or, on the contrary, ride on a convex portion, so that the vehicle body is made to go straight. Even if the steering handle is firmly held, the steering handle may be large due to these irregularities, which makes it difficult to maintain the straightness of the tractor.

In such a case, if the steering angle of the steering wheel is large, the "auto lift control" in which the working machine is raised in association with the operation of the steering wheel or the rear wheel one-side brake is interlocked with the operation of the steering wheel. The effective "auto-break control" sometimes operated unexpectedly.

[0006]

The present invention has been proposed in view of the above-mentioned problems, and therefore, the following technical means have been taken. That is, an auto lift mechanism in which the lift arm 9 is rotated up and down in conjunction with the operation of the steering handle 20, or an auto brake in which the rear wheel brake device 13 on the inside of the turn operates in conjunction with the operation of the steering handle 20. In the tractor having a mechanism, a tilt sensor 32 for detecting the tilt of the body of the tractor is provided on the vehicle body of the tractor, and based on the detection result of the tilt sensor 32, control means 15 for changing the presence or absence of the interlocking or the timing. The tractor swing control device is characterized by being provided with.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. First, the structure will be described. Reference numeral 1 is a tractor, which is provided with front wheels 2 and rear wheels 3, and decelerates rotational power of an engine 5 mounted on the front part of the machine body via a transmission device in a mission case 6 as appropriate. Is transmitted to the front wheel 2 and the rear wheel 3.

A hydraulic cylinder case 8 is mounted on the upper portion of the mission case 6, and lift arms 9 for raising and lowering the work machine are pivotally mounted on both right and left sides of the hydraulic case.
When the hydraulic oil is supplied to or discharged from the single-acting hydraulic cylinder 10 in the hydraulic cylinder case 8, lift arms 9 and 9 are provided.
Rises or falls. Reference numeral 12 shown in FIG. 2 is a hydraulic control valve having three positions of up, neutral, and down. 1
Reference numerals 3 and 13 denote brake devices installed on the rear axles of the left and right rear wheels 3 and 3, which are hydraulically operated and are operated by a command from a controller 15 including a microcomputer as described later, or a brake pedal. When the operator directly depresses 16, 16, hydraulic oil flows into the cylinders 17, 17 of the brake devices 13, 13 to cause the brake devices 13, 13 to operate.
Works. 18a and 18b are solenoids for raising and lowering the hydraulic control valve 12.

Reference numeral 20 denotes a steering wheel, and a steering angle sensor 22 is provided on a turning base of the steering wheel 20 so as to detect a steering amount of the steering wheel 20 and an operation speed per unit time. In this embodiment, an analog sensor is used as the steering angle sensor 22, but a sensor that outputs a pulse signal in proportion to the steering angle may be used.

Reference numeral 23 is a switching valve for actuating the brake device 13, and the brake cylinder is operated by selectively energizing the solenoids 23a, 23b for turning left and turning right. The oil passages to -17 and 17 are switched, and the brake device 13 on the right side or the left side operates.
In FIG. 2, reference numeral 24 is a flow dividing valve, and 25 is a hydraulic pump.

In this embodiment, when the steering handle 20 is rotated by a predetermined angle or more, or when the steering handle 20 is operated at a predetermined operating speed or more, the working machine is interlocked so as to rise. The "auto lift control" and the "auto brake control" in which the one-side brake device 13 of the rear wheel 3 operates when the steering handle 20 is rotated by a predetermined angle or more are configured to operate together. There is.

The timing at which the working machine rises and the timing at which the brake is effective may be substantially the same, but it is desirable that the timing at which the brake is effective is slightly later than the timing at which the working machine is raised because the field is less rough. The tractor-1 can also control the working machine connected to the rear part of the machine body in the left-right direction, and the mechanism therefor will be described. The lift arm 9 and the lower link 27 are connected to each other. Of the lift rods 28, one of the lift rods is composed of a hydraulic cylinder 28r, and the hydraulic cylinder 28r can be expanded and contracted to control the horizontal tilting posture of the rotary tiller 29, which is a working machine. I am trying.

A stroke sensor 3 for detecting the length of the hydraulic cylinder 28r is provided on the lateral side of the hydraulic cylinder 28r.
0 is provided, and an inclination sensor 32 for detecting the lateral inclination of the machine body is provided on the lateral side of the hydraulic cylinder case 8 of the tractor-1. Tilt setting device 33 provided near the cockpit
When the tilt angle of the rotary cultivator 29 is set by, the target position of the hydraulic cylinder 28r is calculated from the detected values of the tilt sensor 32, the stroke sensor 30 and the set value of the tilt setter 33, and the controller 15 outputs the target position. Commanding the extension solenoid 35 or the shortening solenoid 36
Is excited, and the hydraulic cylinder -28r is controlled to expand and contract to the set length.

Next, the schematic structure of the rotary tiller 29 connected to the rear portion of the tractor-1 will be described. The rotary tiller 29 includes a tiller 38 and an upper portion of the tiller 38. The main cover 40 includes a main cover 40 and a rear cover 42 pivotally attached to the rear portion of the main cover 40.
At the rear upper part of 0, a depth sensor 44 for detecting the working depth from the front and rear swing angle of the rear cover 42 is provided. The depth sensor 44 and the working depth setting device 45 are both the controller 1
5, the ascending solenoid 18a or the descending solenoid 18b is excited so that the tilling depth is maintained at the depth set by the tilling depth setting device 45.

In addition, a brief description will be given of the other construction of the tractor shown in FIG. 1. Reference numeral 47 is a position lever, 48 is a position setter attached to the rotating base of the position lever 47, and 49. Is a lift arm angle sensor attached to the base of the lift arm 9, 50 is a lower link, 51 is a top link, and 52 is a universal joint.

FIG. 3 shows various switches, setting devices, detectors, and the controller 1 connected to the controller 15.
5 is a block diagram explaining the relationship between various solenoids and the like connected to the output side of FIG.
The steering angle sensor 22, the position setting device 48, the lift arm angle sensor 49, and the working depth setting device 4 are provided on the input port side of
5, the depth sensor 44, the tilt setting device 33, the stroke sensor 30, and the tilt sensor 32 are connected to the controller 1.
On the output port side of 5, the ascending solenoid 18a, the descending solenoid 18b, the extending solenoid 35, the shortening solenoid 36, the left turning brake solenoid 23a, and the right turning brake solenoid 23b are connected. Has been done.

Next, the operation will be described based on the flowchart of FIG. The control program described in this flow chart is incorporated in the memory device of the controller 15, and the auto lift control is operated or stopped depending on the change rate of the tilt sensor 32. Is configured. First, the states of sensors and setting devices are first read into the controller 15 (step S1), and the rate of change of the steering angle sensor 22 per unit time is calculated (step S2). At this time, when the steering angle of the steering angle sensor 22 is large, for example, when the steering handle 20 is rotated two times (720 degrees) or more in accordance with a turning operation, even if the operating speed of the steering handle 20 is low, Activates the lift control (steps S3, S
8).

In other cases, the detected value relating to the angle of the steering angle sensor 22 and the detected value relating to the operating speed are substituted into the arithmetic expression for determining the autolift control (step S4), and the autolift is performed. When shifting to control,
Further, the rate of change of the tilt sensor 32 is calculated (step S
5, S6). When the rate of change of the tilt signal detected by the tilt sensor 32 is small, the unevenness change is small. In this case, the autolift control is performed (step S8).

On the other hand, if the rate of change is large, it is determined that the vehicle is traveling straight through a rough land such as a ridge or a headland, so the autolift control is stopped at such a location. (Step S9). As described above, according to the above-described example, even if the steering handle 20 is frequently rotated left and right in a place such as a headland where the field is rough, the tilt sensor 32 can detect a sharp shake of the body. As a result, the controller 15 cuts the lifting command to the lifting solenoid 18a, so that the working machine does not go up every time the handle 20 is turned for correcting the trajectory, and the plowing work is good. Is something that can be done.

The above is the description of the operation relating to the auto lift control. Next, based on FIG. 5 to FIG.
The control will be described. FIG. 5 shows how the output signal of the tilt sensor 32 changes, and FIG. 6 illustrates the relationship between the steering angle of the steering wheel 20 and the dead zone width. Explaining the flow chart of FIG. 7, after the initial setting is first made, the detection value of the tilt sensor 32 is read (step # 2), and the variance value V of the sampled detection values of the tilt sensor 32 is calculated. (Step #
3). Then, the detected value θh of the steering angle sensor 22 is input (step # 4), and the simultaneously calculated variance value V and the preset allowable variance value Vmax are compared (step # 5). When the dispersion value is equal to or smaller than the allowable value Vmax, the dead zone width θ is set to a narrow value θmin (step # 6), and when the dispersion value exceeds the allowable value Vmax,
The dead band width is set to a large one (θmax) (step # 9). In this embodiment, the dead band width is represented by the steering angle of the steering wheel. When the dead band width is narrow, the dead band width is ± 180 degrees from the straight travel position, and when it is wide, the dead band width is ± 270 degrees from the straight travel position. There is.

Then, in step # 7, the magnitude relationship between the detected absolute value of the steering angle θh and the dead zone width θ is compared, and when the absolute value exceeds the set dead zone width, the brake device on one side of the rear wheel is compared. 13 is activated (step # 10), and the break output is cut off when it does not exceed (step # 8). As a result, when the dead zone width θ is narrow, the steering handle 20 is set to ± 1.
The braking device 13 on the inside of the turning does not operate even if the turning operation is performed within the range of 80 degrees, and the breaking device 13 operates only when the turning operation is exceeded.

When the dead zone width is wide, ± 270
The brake device 13 does not work even if the steering handle 20 is rotated to the degree range, and the brake device 13 operates when the steering handle 20 exceeds the range. In this embodiment, the width of the dead zone is narrowed during the usual plowing work in the field, and the dead zone is widened in a rough place such as a headland. Moreover, this dead band width switching does not require any manual operation, but is automatically switched by a command from the controller 15 by picking up the signal from the tilt sensor 32, so that no burden is imposed on the operator. The operation is easy, and there is no problem that the auto-break operates during work.

In the embodiment shown in FIGS. 8 to 10, instead of the dead zone width adjustment, the brake braking force itself is changed. In this case, as shown in FIG. 9, the braking force is set to be weaker in the headland as compared with the tilling work in the field. Next, the flow chart of FIG. 10 will be described. Variance value V and allowable variance value V in step T5
When the calculated variance value V exceeds the allowable variance value Vmax, the brake braking force is weakened (step T7). Conversely, when the variance value V is less than the allowable variance value Vmax, -K Strengthen the braking force (Step T
6) I am doing so.

Although the brake braking force is switched in the two-step switching system in this embodiment, it may be configured to switch more than that. Further, the curve of the braking force may use a quadratic function instead of a linear function.

[0025]

As described above, according to the present invention, the lift arm moves up and down in conjunction with the steering wheel operation.
A tractor having an auto-brake mechanism in which a rear-wheel brake device on the inside of a turn operates in conjunction with a lift mechanism or a steering handle operation, wherein the tractor-an inclination sensor for detecting a lateral inclination of a vehicle body on a vehicle body. Is provided
Based on the detection result of the tilt sensor, a control means is provided for changing the presence or absence of the interlocking or the timing. Therefore, in order to maintain straightness in a rough field such as a headland, the steering handle is used. Auto-lift control and auto-brake control do not accidentally operate even if the machine is rotated frequently, and the burden on the operator during turning is significantly reduced, and operability and workability are significantly improved. It has the characteristics described below.

[Brief description of drawings]

FIG. 1 is a side view of an entire tractor.

FIG. 2 is a hydraulic circuit diagram.

FIG. 3 is a control block diagram.

FIG. 4 is a flow chart of auto lift control.

FIG. 5 is a graph illustrating changes in the output signal of the tilt sensor.

FIG. 6 is a graph showing a relationship between a steering angle and a dead zone width.

FIG. 7 is a flowchart relating to auto-break control.

FIG. 8 is a graph illustrating changes in the output signal of the tilt sensor.

FIG. 9 is a graph illustrating a relationship between a steering angle and a brake braking force.

FIG. 10 is a flowchart relating to auto-break control.

[Explanation of symbols]

 1 tractor 2 front wheel 3 rear wheel 5 engine 6 mission case 8 hydraulic cylinder case 9 lift arm 13 brake device 15 controller 20 steering wheel 22 steering angle sensor

Claims (1)

[Claims] 1. An auto lift mechanism in which a lift arm moves up and down in conjunction with operation of a steering handle, or a rear wheel blur inside a turning in conjunction with operation of a steering handle.
In a tractor equipped with an auto-break mechanism for operating a key device, a tilt sensor for detecting a lateral tilt of a vehicle body is provided on the tractor body, and whether or not the tilt sensor is interlocked based on the detection result of the tilt sensor. Alternatively, a turning control device for a tractor, which is provided with control means for changing timing.