JP3680331B2 - Auto braking control device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a tractor autobraking control device, and more particularly to an autobraking control device that brakes an inner rear wheel during turning.
[0002]
[Prior art]
The rear wheels of the tractor are provided with a pair of brake devices that can be operated independently on the left and right sides. When turning the aircraft during plowing work, only one brake pedal is depressed to press the rear wheel inside the turn. Brake is applied to reduce the turning radius of the aircraft.
[0003]
In addition, a sensor is provided in the steering mechanism to detect the steering angle of the steering, and when the steering angle exceeds a certain value, it is considered that the aircraft is turning and an auto brake that automatically brakes the rear wheels inside the turning. Braking devices are also known.
[0004]
[Problems to be solved by the invention]
The conventional tractor auto-braking device automatically brakes the inner rear wheel when turning, but the braking force of the rear wheel is constant. The braking force cannot be changed. For this reason, there have been problems such as the turning trace being rough due to the locking of the inner rear wheel, or the aircraft being unable to turn due to the slip of the outer rear wheel.
[0005]
Therefore, there is a technical problem to be solved in order to change the braking force of the rear wheel depending on the traveling state of the tractor and the state of the field and to exhibit smooth turning performance, and the present invention solves this problem. For the purpose.
[0006]
[Means for Solving the Problems]
The present invention has been proposed in order to achieve the above-mentioned object. When the airframe turns, the rear wheel inside the turn is braked, and an electromagnetic proportional valve is provided in the hydraulic circuit for braking the rear wheel. An automatic braking control device configured to switch the duty ratio of the control signal of the electromagnetic proportional valve so that the braking force of the rear wheel can be selected in a plurality of stages , wherein the duty ratio of the control signal of the electromagnetic proportional valve is changed. when switched, in the automatic braking control apparatus of the detection result more, as to control the braking of the turning inner rear wheel by the rotation sensor is provided for detecting the rotational speed of the left and right rear wheels, The rotation sensors are provided on the left and right sides, respectively, to detect the rotation ratio of the left and right rear wheels, and when the detected rotation ratio is greater than a certain range, the rear wheels on the inside of the turn are considered to be in a locked state, Inside the swivel Providing is configured by the automatic braking control apparatus to be used for tractors so that the duty ratio is changed to the on-time of the control signal to the wheel small.
[0007]
[Action]
The autobraking control device according to the present invention controls the braking of the turning rear rear wheel based on the detection result of the rotation sensor provided to detect the rotational speed of the left and right rear wheels. In this case, the rotation sensors are provided on the left and right sides, respectively, to detect the rotation ratio of the left and right rear wheels, and when the detected rotation ratio is larger than a certain range, the rear wheel on the inside of the turn is locked. It is considered that the duty ratio is changed so as to reduce the ON time of the control signal to the rear wheel inside the turn and is used for the tractor , so that smooth turning performance can be exhibited. it can.
[0008]
【Example】
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a tractor 11, in which a traveling clutch 13 is provided at a rear portion of an engine 12, and a power transmission mechanism portion 17 such as a front mission 15 and a rear mission 16 is connected to a rear portion via a spacer case 14. The power of the engine 12 is transmitted to the rear wheels 18a and 18b.
[0009]
The power of the engine 12 is also transmitted to the front wheels 20a and 20b by the drive switching unit 19. Inside the drive switching unit 19, power transmission at substantially constant speed with the rear wheels is turned on and off to the front wheels 20a and 20b. A drive switching device 19a and a double speed device 19b for transmitting power to the front wheels 20a and 20b at a rotational speed substantially twice that of the rear wheels when turning are provided.
[0010]
On the other hand, left and right brake pedals 21 and 22 are provided on the right side of the spacer case 14 and are pivotally mounted so that they can be pressed independently. If the left brake pedal 21 is stepped on, the brake rod 24 provided on the left side of the spacer case 14 is pulled by the rotation of the pedal shaft 23, and the left brake arm 25 rotates forward to the left. The rear wheel brake device 26 operates. When the right brake pedal 22 is depressed, the brake rod 27 provided on the right side of the spacer case 14 is pulled, the right brake arm 28 rotates forward, and the brake device 29 for the right rear wheel operates. To do.
[0011]
The left and right rear axle housings 30 and 31 are provided with hydraulic actuators 32 and 33 in a system different from the linkage of the brake pedals 21 and 22 described above, and by turning on the hydraulic actuators 32 and 33, the brake arms 25, 28 is pushed forward, and the left and right brake devices 26 and 29 are configured to operate.
[0012]
On the other hand, a steering angle sensor 35 is provided on the steering shaft 34 to detect the steering angle of the steering 36. Also, a lift cylinder 38 is provided on the upper part of the rear mission case 16, and the left and right lift arms 39, 39 are rotated up and down by the expansion and contraction of the lift cylinder 38, so that the working machine (not shown) is raised and lowered to an arbitrary height. Let Further, a lift arm sensor 40 is provided at the rotation base of one lift arm 39, and the lift height of the work implement is detected by the lift arm sensor 40. Reference numeral 41 is a controller, and 42 is a changeover switch.
[0013]
FIG. 2 is a block diagram of the autobraking control device. The power branched left and right by the rear differential 43 is transmitted to the wheel gears 44 and 45, and the left and right rear wheels 18a and 18b rotate. The left and right wheel gears 44 and 45 are provided with rotation sensors 47 and 48, respectively, and the rotation sensors 47 and 48 detect the rotation speeds of the left and right rear wheels 18a and 18b. Reference numeral 46 denotes a front differential.
[0014]
The hydraulic circuit that brakes the rear wheels 18a and 18b is provided with an electromagnetic proportional valve 49, which outputs a pulse signal from the controller 41 to the left solenoid 50 or the right solenoid 51 to actuate the electromagnetic proportional valve 49 in a pulsating manner. Is supplied to the left hydraulic actuator 32 or the right hydraulic actuator 33. When the hydraulic actuator 32 or 33 is turned on, the left and right brake devices 26 and 29 operate independently from each other, and the rear wheels 18a or 18b are braked independently.
[0015]
On the other hand, the change-over switch 42 is for switching the braking force of the left and right brake devices 26 and 29, and is “1 strong”, “2 middle”, “▲” depending on the traveling state of the tractor and the state of the field. A selector is provided so that three braking forces of “3 ▼ weak” can be selected. For example, since the ground is hard in dry fields, the field is rarely roughened even when the changeover switch 42 is set to “1 strong” and the braking force of the rear wheels is increased, but in wet fields, the ground is soft. Therefore, the changeover switch 42 is set to “3 weak”, and the braking force of the rear wheels is slightly reduced to prevent slipping and roughening of the turning trace.
[0016]
In addition, an angular velocity sensor 53 is attached to the airframe, and the angular velocity when the tractor 11 is turning is detected and sent to the controller 41 so that the turning state of the airframe can be grasped.
[0017]
Next, automatic braking control will be described with reference to the flowchart of FIG. First, the detection values of the sensors such as the steering angle sensor 35 and the rotation sensors 47 and 48 are read, and the operation states of the switches including the changeover switch 42 are read (step 101). When the changeover switch 42 is in the “1” strong position, the controller 41 is set to continuously output a signal from the controller 41 to the solenoid 50 or 51 of the electromagnetic proportional valve 49 (step 102 → 103). When the switch 42 is in the “(2) middle” position, the signal from the controller 41 is set so as to be output at a duty ratio of ON time 100: OFF time 100 (step 102 → 104). Further, when the changeover switch 42 is in the position of “3 weak”, the signal from the controller 41 is set so as to be output at a duty ratio of ON time 70: OFF time 100 (step 102 → 105). .
[0018]
Thus, when the controller 41 determines that the aircraft has entered the turning state based on the detection value of the steering angle sensor 35, the brake output is set so as to brake the rear wheel 18a or 18b inside the turning (step 106). ). When the aircraft is turning left, the duty ratio signal set in steps 103 to 105 is output to the left solenoid 50 of the electromagnetic proportional valve 49 (step 107 → 108), and the spool of the electromagnetic proportional valve 49 is switched to the position 49a. Then, pressure oil is supplied to the left hydraulic actuator 32.
[0019]
At this time, the left hydraulic actuator 32 is driven in a pulse manner according to the duty ratio selected by the changeover switch 42, the brake device 26 is intermittently operated, and the left rear wheel 18a is controlled in accordance with the state of the field. It is braked by power.
[0020]
On the other hand, when the aircraft is turning right, the duty ratio signal set in steps 103 to 105 is output to the right solenoid 51 of the electromagnetic proportional valve 49 (step 107 → 109), and the spool of the electromagnetic proportional valve 49 is set to 49b. The pressure oil is supplied to the right hydraulic actuator 33 by switching to the position. Also at this time, the right hydraulic actuator 33 is driven in a pulse manner as described above, the brake device 29 is intermittently operated, and the right rear wheel 18b is braked with a braking force adapted to the state of the field.
[0021]
If the airframe is not in the turning state, the brake output is not set in step 106, and the signal output to the left and right solenoids 50 and 51 is turned off (step 107 → 110).
[0022]
Thus, when the inner rear wheel 18a or 18b is braked during turning of the tractor 11 to reduce the turning radius, the operator can appropriately select the braking force with the changeover switch 42 according to the state of the field in advance. The rear wheel inside the turn is braked with the optimum braking force without locking.
[0023]
Here, when the changeover switch 42 is not provided, the sensors and switches are read as shown in the flowchart of FIG. 4, and when the aircraft enters a turning state, the rear wheels inside the turning are braked. Set the brake timing as follows. Then, the rotation speed of the rear wheels 18a and 18b is detected by the rotation sensors 47 and 48, and if the rear wheel on the inside of the turn which is performing the brake output is rotating, the brake output is continued and the rotation of the rear wheel is eliminated. When this happens, it is considered that the rear wheel is locked, and the brake output is temporarily turned off to release the braking.
[0024]
After that, when the rear wheel starts to rotate, the brake output is performed again, so that the rear wheel on the inside of the turn is braked by a so-called pumping brake, and the optimum is achieved without locking the rear wheel. A braking force can be obtained, and roughening of the turning trajectory in the field can be prevented.
[0025]
Further, as shown in the flowchart of FIG. 5, the rotation ratio of the left and right rear wheels 18a and 18b is detected during a turn, and when the rotation ratio is larger than a certain range, the rear wheel inside the turn is regarded as being in a locked state. The duty ratio is changed so that the ON time of the control signal from the controller 41 is reduced. Accordingly, the braking force of the rear wheel on the inside of the turn is reduced, and the rear wheel can be prevented from being locked.
[0026]
FIG. 6 controls the braking force based on the detection value of the angular velocity sensor 53, and in the same manner as in the other flowcharts described above, first, each sensor and switch are read (step 201), and the airframe is in a turning state. When entering, the brake timing is set so as to brake the rear wheel inside the turn (step 202). When a brake output request is made, the process proceeds from step 203 to 204. Immediately after the start of turning and a brake output request is made, whether or not the rear wheels on the inside of the turn are locked by the detected values of the rotation sensors 47 and 48. Is determined (step 205). If the rear wheel is not locked, the process returns to step 204. If the rear wheel is locked, the control signal ON time is set based on the detected value of the angular velocity sensor 53 (step 206).
[0027]
When the aircraft's angular velocity is high when the rear wheel on the inside of the turn is locked at the beginning of the turn of the aircraft, it means that the aircraft is turning rapidly in a short time and the ground such as dry fields is solid Often. In this case, even if the state where the rear wheel on the inside of the turn is kept locked is maintained, the aircraft can turn without damaging the field, so that the on time of the control signal is increased as shown in FIG. Set the duty ratio to.
[0028]
On the other hand, if the aircraft's angular velocity is low when the rear wheel on the inside of the turn is locked at the beginning of the turn of the aircraft, it will be difficult for the aircraft to turn rapidly, and the ground such as wet fields will be soft. There are often. In this case, since it is considered that the rear wheels on the outside of the turn are slipping, the duty ratio is set so as to reduce the ON time of the control signal as shown in FIG. Reduces the braking force. In that case, the rear differential 43 prevents the slip of the rear wheel on the outside of the turn so that the aircraft can turn smoothly.
[0029]
When the brake output is on the left side, the control signal of the set duty ratio is output to the left solenoid 50 to control the electromagnetic proportional valve 49 (step 207 → 208), and when the brake output is on the right side Then, the control signal of the set duty ratio is output to the right solenoid 51 to control the electromagnetic proportional valve 49 (step 207 → 209).
[0030]
In step 202, when the brake timing is not set and the brake output is not requested, the process jumps from step 203 to 210, and the signal output to the left and right solenoids 50 and 51 is turned off.
[0031]
On the other hand, if it is after the mid-turn of the airframe, the process proceeds from step 204 to 211, and the duration of the detection signal of the angular velocity sensor 53 is measured. When the angular velocity is generated in the airframe and the duration is long, it is possible that the airframe is difficult to turn and the rear wheel outside the turn is slipping. Therefore, as shown in FIG. 8, according to the duty ratio of the control signal that is currently set, the duty ratio is corrected and set so that the on-time decreases as the angular velocity duration time increases ( Step 212), the process proceeds to Step 207.
[0032]
In other words, based on the detection value of the angular velocity sensor 53, the turning state of the aircraft can be inferred from the magnitude of the angular velocity displacement of the aircraft, and by changing the ON time of the control signal of the brake output, the optimum according to the field conditions Auto-braking control can be performed.
[0033]
It should be noted that the present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.
[0034]
【The invention's effect】
The present invention is an auto-braking control device in which the duty ratio of the control signal of the electromagnetic proportional valve is switched so that the braking force of the rear wheel can be selected in a plurality of stages, and the duty of the control signal of the electromagnetic proportional valve is when switching the ratios, at the automatic braking control system more of a detection result by the rotation sensor provided, so as to control the braking of the turning inner rear wheel and to detect the rotational speed of the left and right rear wheels And
The rotation sensors are provided on the left and right sides, respectively, to detect the rotation ratio of the left and right rear wheels, and when the detected rotation ratio is greater than a certain range, the rear wheels on the inside of the turn are considered to be in a locked state, Since the autobraking control device is provided for tractors so that the duty ratio is changed so as to reduce the ON time of the control signal to the rear wheels inside the turn, the rear of the tractor inside the turn The braking force of the wheel is reduced, and the rear wheel can be prevented from being locked.
Accordingly, smooth turning performance can be exhibited by changing the braking force of the rear wheels in accordance with the traveling state of the tractor and the state of the field and controlling the locking and slipping of the rear wheels.
In addition, by exhibiting smooth turning performance without locking the turning inner rear wheel, the field can be prevented from being rough due to turning marks.
[Brief description of the drawings]
FIG. 1 is a side view of a tractor according to an embodiment of the present invention.
FIG. 2 is a block diagram of an automatic braking control device.
FIG. 3 is a flowchart of autobraking control.
FIG. 4 is a flowchart of autobraking control when there is no changeover switch.
FIG. 5 is a flowchart of autobraking control based on left and right rotation ratios.
FIG. 6 is a flowchart of autobraking control based on the angular velocity displacement of the airframe.
FIG. 7 is a graph for obtaining a duty ratio according to the magnitude of the angular velocity at the beginning of turning.
FIG. 8 is a graph for obtaining the angular velocity duration time of the aircraft and the duty ratio for each on-time after the middle of turning.
[Explanation of symbols]
11 Tractors 18a, 18b Rear wheels 26, 29 Brake devices 32, 33 Hydraulic actuator 35 Steering angle sensor 36 Steering 41 Controller 42 Changeover switch 49 Proportional solenoid valve 50, 51 Solenoid

Claims (1)

When turning the airframe, the rear wheel inside the turn is braked, and an electromagnetic proportional valve is provided in the hydraulic circuit that brakes the rear wheel, and the duty ratio of the control signal of the electromagnetic proportional valve is switched to change the rear a automatic braking control apparatus selectably forms a braking force of the wheel in a plurality of stages, when switching the duty ratio of the control signal of the electromagnetic proportional valve, in order to detect the rotational speed of the left and right rear wheels more detection result of the rotation sensor provided, in the automatic braking control apparatus that controls the braking of the turning inner rear wheel,
The rotation sensors are provided on the left and right sides, respectively, to detect the rotation ratio of the left and right rear wheels. An autobraking control device configured to be used for a tractor so that a duty ratio is changed so as to reduce an ON time of a control signal to a rear wheel inside a turn .

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