JP2870420B2 - Tractor turning control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tractor turning control device, which facilitates turning operation of an aircraft at a ridge or the like.

[0002]

2. Description of the Related Art Conventionally, there has been a configuration in which a steering wheel is turned, and when the steering wheel is operated at a predetermined angle or more, a brake inside a rear wheel is automatically activated so as to be effective.

[0003]

By the way, in such a conventional device, the steering handle and the rear wheel one-side brake are provided.
The brake device was mechanically linked, so not only when moving forward, but also when turning the aircraft backward, the brake on the inside of the turn was applied, and the relatively soft field that had just been plowed could be used. There was a problem that it was ruined by the rear wheel.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and the following technical measures have been taken. That is, the rear wheel brake device 13 inside the turning is interlocked with the operation of the steering handle 20.
In a tractor provided with an auto-brake mechanism for operating the vehicle, a means 26 for detecting a reverse operation of the fuselage is provided, and when the reverse detection means 26 detects the reverse movement of the fuselage, the interlock is released, or The tractor turning control device is characterized in that a weak braking is applied.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. First, a description will be given of the structure. Reference numeral 1 denotes a tractor provided with a front wheel 2 and a rear wheel 3, which appropriately reduces the rotational power of an engine 5 mounted on the front part of the fuselage through a transmission in a transmission case 6. Is transmitted to the front wheel 2 and the rear wheel 3. In the transmission case 6, a hydraulic forward / reverse switching mechanism 7 for changing the advancing direction of the vehicle forward and backward, and a synchromesh type main / auxiliary transmission 4 capable of four-speed shifting, respectively.
Are incorporated in series.

A hydraulic cylinder case 8 is mounted on the upper part of the transmission case 6, and lift arms 9, 9 for lifting and lowering the working machine are pivotally mounted on both left and right sides thereof.
When hydraulic oil is supplied or discharged to the single-acting hydraulic cylinder 10 in the hydraulic cylinder case 8, the lift arms 9, 9 are lifted.
Rises or falls. Numeral 12 shown in FIG. 3 is a hydraulic control valve having three positions: up, neutral, and down. 1
Reference numerals 3 and 13 denote braking devices installed on the rear axles of the left and right rear wheels 3 and 3, which are hydraulically operated, and which are controlled by a command from a controller 15 comprising a microcomputer or a brake pedal as will be described later. When the operator directly steps on the brake devices 16, 16, the hydraulic oil flows into the cylinders 17, 17 of the brake devices 13, 13 and the brake devices 13, 13
Operates. Reference numerals 18a and 18b denote solenoids for raising and lowering the hydraulic control valve 12.

Reference numeral 20 denotes a steering handle, which is provided with a steering angle sensor 22 at a rotation base thereof, so as to detect a steering amount of the steering handle 20. In this embodiment, the steering angle sensor 22 uses an analog sensor. However, a system that outputs a pulse signal in proportion to the steering angle may be used. A forward / reverse switching mechanism 7 is provided in the vicinity of the turning operation section of the steering handle 20.
And a forward / reverse switching lever-21 for changing the traveling direction of the aircraft by 180 degrees. When the lever-21 is rotated to the front side, the fuselage moves forward, and when the lever-21 is moved to the rear side, the fuselage moves backward. A reverse detection switch 26 for detecting a reverse operation of the fuselage is provided at the rotation base of the forward / reverse switching lever-21.

Reference numeral 23 denotes a switching valve for operating the brake device 13. The switching valve 23 is provided for selectively turning left and right turning solenoids 23a and 23b. The oil passages leading to the cylinders 17 and 17 are switched, and the right or left brake device 13 operates. In FIG. 3, reference numeral 24 denotes a flow dividing valve, and reference numeral 25 denotes a hydraulic pump.

Next, a rotary tilling device 29 connected to the rear of the tractor 1 will be described. The rotary tilling device 29 will be described in detail below. The main cover 40 includes a main cover 40 to be covered, and a rear cover 42 pivotally attached to a rear portion of the main cover 40.
A depth sensor 44 for detecting a plowing depth based on a front and rear swing angle of the rear cover 42 is provided at an upper rear portion of the rear cover 0. Both the depth sensor 44 and the depth setting device 45 are provided with the controller 1.
5, the ascending solenoid 18a or the descending solenoid 18b is excited so that the tillage depth is maintained at the depth set by the tillage depth setting device 45.

[0010] To briefly describe another structure of the tractor shown in FIG. 1, 47 is a position lever, 48 is a position setting device attached to a rotation base of the position lever 47, and 49 is a lifter. A lift arm angle sensor attached to the base of the arm 9, an auto mode setting switch 50 for turning on / off the auto brake control;
Reference numeral 51 denotes a switch for changing the effect of the brake device 13. When the switch 51 is turned on, the effect of the brake is increased, and when the switch 51 is turned off, the effect is weakened. Specifically, the pressure control valve 52 described in the hydraulic circuit of FIG. 3 is adjusted to switch between forced operation and weak braking.

FIG. 4 shows various switches, setting devices, detectors and the like connected to the controller 15 and the controller 1.
5 is a block diagram for explaining the relationship between various solenoids and the like connected to the output side of the controller 5.
On the input port side, a steering angle sensor 22, a position setting device 48, a lift arm angle sensor 49, a tillage depth setting device 4
5, depth sensor 44, auto mode setting switch 5
0, braking pressure switch 51, reverse detection switch 26
Are connected to the output port side of the controller 15 for raising the solenoid 18a, for lowering the solenoid 18b, for the solenoid 23a for the left turning brake, for the solenoid 23b for the right turning brake, and for adjusting the braking pressure. The solenoid 52a is connected.

Next, the operation will be described with reference to the flowchart of FIG. In the field, the brake pressure changeover switch 51 is used to ensure the operation of the auto brake control.
Is set to ON to set the effectiveness of the brake device 13 to "strong" braking. The operation will be described based on the flowchart. First, the state of the sensor, the setting device, and the switch is read into the controller 15 (step S1).

At this time, the auto mode setting switch 50
Is OFF, no matter how the steering handle 20 is turned, the turning brake solenoid 23a,
23b is not excited (steps S2, S3,
S4). Therefore, the turning operation mainly by the steering handle 20 is performed. When the aircraft is moving forward and the auto mode setting switch 50 is ON and the brake force setting is "strong" braking, the steering handle 20 is turned to one side by a predetermined angle or more. Then, the steering angle sensor 22 detects it.

For example, when the steering handle 20 is turned to the left (step S8), the solenoid 23a for the left turn brake is turned on (step S9), and the solenoid 23b for the right turn brake is turned off. (Step S10). In this case, the left brake device 13 operates in a "strong" braking state. Conversely, when the steering handle 20 is operated to the right, the right turn brake solenoid 23b is turned on and the left turn brake solenoid 23a is turned off (steps S11, S12). Also in this case, the braking device 13 performs "strong" braking.

On the other hand, when the forward / reverse switching lever 21 is operated to rotate backward to retreat the body, the reverse detection switch 2 is operated.
6 is turned on (step S7), the brake braking force is weakened, and more specifically, the pressure regulating valve 52 is controlled in a direction to weaken the brake braking force. In this state, the steering handle 20 is turned to the right. Then, the brake device 13 on the right side operates in the "weak" braking state (step S14).

Conversely, when the steering handle 20 is turned leftward, the brake device 13 on the left side operates in the "weak" braking state (step S16). As described above, in the device of the above-described embodiment, since the "strong" braking is performed when the vehicle is moving forward and the "weak" braking is performed when the vehicle is moving backward, the trace of plowing once by the rotary tillage device or the like is used for the tractor-1. The rear wheel 3 can turn the aircraft with a small turning radius as much as the light braking force is applied without being roughened.

In this embodiment, when the vehicle is moving forward, "strong" braking is performed, and when the vehicle is moving backward, "weak" braking is performed. However, braking may be performed when moving forward, and no braking may be performed when moving backward. If no braking is applied at the time of reverse travel, the turning radius will be slightly larger, but the roughening of the field by the rear wheels 3 will be reduced. The flowchart shown in FIG.
This is an explanation of a program relating to auto-lift control used in the tractor-1.

If the steering angle sensor 22 of the tractor-1 and the ascending solenoid 18a and the descending solenoid 18b of the hydraulic control valve 12 are electrically linked, auto-lift control in which the working machine rises during turning can be performed. Become. in this case,
If the operation of the steering handle 20 is simply linked with the lifting and lowering of the work implement, the steering implement 20 may be instantaneously turned in the left and right direction when traveling straight, and as a result, the work implement may rise.

For example, in a place where the ground is rough, such as a headland, the steering wheel 20 is easily taken by the front wheel 2 due to the influence of the unevenness of the ground. Will swing. This improved device prevents the work implement from rising when the steering handle 20 is displaced in either the left or right direction from the straight traveling position in cases other than the turning operation.

The operation will be described with reference to the flowchart. First, the values of various sensors and setting devices are read (step # 1). At this time, when the raising command is input to the controller 15 by operating the position lever or the like, the work implement rises (step # 2). Then, it is read whether or not an auto mode setting switch (not shown) is turned on to operate the auto lift control (step # 3).

When the steering handle 20 is rotated left or right from the straight traveling direction, the time required for the steering handle 20 to return to the straight traveling position is measured (step # 9). At this time, a timer for changing the auto-lift timing, which will be described later, is not operating for the first time, and the control is performed based on the standard arithmetic expression (A) shown in FIG. (FIG. 7 shows the rotational speed of the steering handle 20 on the horizontal axis and the angle of the steering handle 20 on the vertical axis.) As a result of substituting the detection value of the steering angle sensor 22 into this equation, the auto-lift control is performed. If it is in a state where can be operated, the work machine is raised (steps # 13, # 14).
Then, as a result of measuring the time required to return to the straight-ahead position when the steering handle 20 is rotated to one side, if the time is less than a predetermined value, in other words, it does not accompany a normal turning operation, The steering handle 20 is momentarily rotated to one side, and momentarily (0.3 to
If it is determined that the vehicle has returned to the straight traveling direction (0.5 seconds), the auto-lift timing change timer is operated (step # 8). The setting time of this timer may be about 1 to 2 seconds.

If the steering handle 20 is deviated from straight running and is turned to one side while the change timer is operating, the timing at which the auto-lift control is effective is calculated according to the arithmetic expression (b) in FIG. It is changed to the one based on. That is, the timing at which the work implement rises is delayed. Then, in this case, if the condition for raising the work implement is satisfied, the work implement is raised (step # 1).
At the same time, both the auto-lift change timer and the timer for measuring the time during which the steering wheel 20 has deviated from the straight-ahead position are reset (steps # 15, # 16).

In such an improved tractor with auto-lift control, if the time required for the steering handle 20 to turn from the straight-ahead position to one side and return to straight-ahead is extremely short, the auto-lift is performed. Since the timing at which the control is effective is delayed, the work implement does not rise carelessly.

[0024]

As described above, the present invention relates to a tractor having an auto-brake mechanism in which a rear-wheel brake device for turning inside operates in conjunction with operation of a steering handle as described above. A means for detecting a reverse operation is provided,
When the reverse detection means detects the backward movement of the aircraft, the interlock is released or light braking is applied, so that when the aircraft is moved backward, the field is strongly scratched by the rear wheels that are braked. This eliminates the problem of damaging the cultivated soft field.

[Brief description of the drawings]

FIG. 1 is a side view of an entire tractor and a rotary tilling device.

FIG. 2 is a plan view of a rotation operation unit of a forward / reverse operation lever.

FIG. 3 is a hydraulic circuit diagram.

FIG. 4 is a control block diagram.

FIG. 5 is a flowchart of an auto brake control.

FIG. 6 is a flowchart of auto-lift control.

FIG. 7 is a graph in which the horizontal axis represents the steering wheel rotation speed and the vertical axis represents the steering wheel operation angle.

[Explanation of symbols]

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

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-31883 (JP, A) JP-A-60-51909 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) A01B 69/00 302 B62D 11/08

Claims (1)

(57) [Claims] A tractor provided with an auto-brake mechanism for operating a rear-wheel brake device on the inside of a turn in conjunction with operation of a steering handle is provided with means for detecting a reverse operation of the fuselage. A turning control device for a tractor, characterized in that when the detecting means detects the backward movement of the body, the interlock is released or a weak braking is applied.