JPH05319297A - Four-wheel steering controller - Google Patents

Abstract

PURPOSE:To improve the operation performance by allowing the return to the manual steering mode when a manual selection pushing button switch is operated during the automatic control mode, while allowing the return to the automatic control mode when both modes accord, as for a four-wheel steering controller equipped with the automatic control mode for a tractor, etc. CONSTITUTION:Pushing button switches for each manual selection for the front wheel steering mode, rear wheel steering mode, and four-wheel steering mode and an automatic control mode switch are connected directly with an input interface. When the automatic control mode is set by the automatic control mode switch, automatic control is carried out in correspondence with each steering mode according to the output signals of a front wheel steering angle sensor, rear wheel steering angle sensor, control lever turning angle sensor, and a speed change lever position sensor. At this time, if a manual pushing button is pushed, the selection to the steering mode is performed in priority. When the manual steering mode and automatic steering mode accord, automatic return to the automatic control is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a four-wheel steering control device, and more particularly, it has an automatic control mode for determining a steering mode depending on an operating position of a control lever for raising and lowering a working machine and an operating position of a shift lever. The present invention relates to a four-wheel steering control device.

[0002]

2. Description of the Related Art Recently, an increasing number of power vehicles, such as tractors and passenger management machines, are capable of steering both front and rear wheels. Known configurations of the four-wheel steering system include a system in which a steering mode is switched by a combination of gears, and a system in which front and rear wheels are provided with steering cylinders to steer hydraulically.

For example, in a structure in which steering is performed by hydraulic pressure, both front and rear wheels can be steered by switching electromagnetic valves by a push button switch to extend or contract the front and rear steering cylinders. Then, each steering mode switched by the push button switch is displayed on a display means such as a lamp so that it is possible to confirm which mode such as a front wheel steering mode, a rear wheel steering mode, a four-wheel steering mode or the like. ..

Here, a power vehicle such as a tractor or a passenger management machine is constructed such that a working machine such as a rotary is attached to a rear portion thereof, and the working machine is moved up and down by operating a control lever. There is also known a four-wheel steering system having an automatic control mode in which the steering mode is determined by the operating position of the control lever and the operating position of the shift lever that switches the transmission. In this automatic control mode, the four-wheel steering mode is automatically set when the control lever is operated to a position higher than a predetermined value, so that the vehicle can be easily turned. Further, when the shift lever is operated to the reverse position, the rear wheel steering mode is set to improve the straightness of the body during the reverse.

[0005]

The four-wheel steering control device having the above-mentioned automatic control mode automatically operates when the shift lever is operated to the reverse position while the power vehicle is operating in the automatic control mode. Switch to rear wheel steering mode. Here, if the push button switch for manual switching is pushed, the manual operation is prioritized. For example, when the push button switch in the four-wheel steering mode is pushed, the manual priority control mode is forcibly switched to the four-wheel steering mode. Then, in order to return to the automatic control mode, the push button switch in the four-wheel steering mode must be pressed again. In that case, the automatic control mode is restored, and the rear wheel steering mode is changed again from the position of the shift lever. Become. Therefore, the operator may make an erroneous decision as to which steering mode the machine being operated is in, and the operability is not good.

Therefore, a solution is provided so that the operator can perform a manual operation in the automatic control mode without causing a feeling of strangeness in the operation, and can select an arbitrary steering mode depending on the shape of the field and the working mode. A technical problem to be caused arises, and an object of the present invention is to solve this problem.

[0007]

The present invention has been proposed in order to solve the above-mentioned problems, and a steering cylinder is provided for each of the front wheels and the rear wheels, and solenoid valves are switched to change the front and rear steering cylinders. Equipped with a four-wheel steering mode in which both the front and rear wheels can be extended and retracted, and when the control lever for raising and lowering the work implement is operated to a raised position above a predetermined value, the four-wheel steering mode is entered and the transmission lever is moved backward. In the four-wheel steering control device having an automatic control mode in which the steering mode is determined by the operating position of the control lever and the operating position of the shift lever so that the rear wheel steering mode is set when the steering wheel is operated to the position. When a push button switch for manual switching is operated during the mode, a manual priority control mode is provided to switch to the steering mode of the operated push button switch. Provided is a four-wheel steering control device in which the manual priority control mode is canceled and the automatic control mode is restored when the steering mode in the control mode matches the steering mode determined by the automatic control mode. Is.

[0008]

The four-wheel steering control device of the present invention has an automatic control mode in which the steering mode is determined by the operating position of the control lever and the operating position of the speed change lever. When the push button switch is operated, the manual priority control mode is set, and the steering mode of the operated push button switch is switched. After that, the manual operation is prioritized, but the control unit stores the steering mode during the manual operation, and the steering mode and the manual priority control in the automatic control mode are determined by the operation position of the control lever and the operation position of the speed change lever. When the mode matches the steering mode, the manual priority control mode is released and the automatic control mode is restored.

[0009]

An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a hydraulic circuit of a four-wheel steering control device provided in a power vehicle. The knuckle arms 12, 12 of the front wheels 11, 11 are connected by a tie rod 13, and one of the knuckle arms 12 is connected. The cylinder rod 15 of the steering cylinder 14 is connected to. In the steering cylinder 14, a hydraulic circuit is connected to a solenoid valve 18 through oil passages 16 and 17, and the solenoid 19 is off and the solenoid valve 18 is in the illustrated state.
Is located at the position 18a. Then, a sensor 2 for detecting a steering angle is attached to a rotating portion of the knuckle arm 12 on the front wheel side.
Set 0.

On the other hand, the knuckle arm 2 of the rear wheels 21, 21
The tie rods 23 are also connected between the Nos. 2 and 22, and one of the knuckle arms 22 is extended to the opposite side to connect the cylinder rod 25 of the steering cylinder 24. In the steering cylinder 24, a hydraulic circuit is connected to a solenoid valve 28 through oil passages 26 and 27. In the illustrated state, the solenoid 29 is off and the spool of the solenoid valve 28 is at the position 28a. Then, a sensor 30 for detecting the steering angle is provided on the rotating portion of the knuckle arm 22 on the rear wheel side.

Reference numeral 31 denotes an all-hydraulic controller, which is formed so that the oil discharged from the hydraulic pump 33 is led out from the oil port L or the oil port R depending on the steering direction of the steering wheel 32 and the amount of rotation. The oil port L and the solenoid valve 18 are connected by an oil passage 34, and the oil port R and the solenoid valve 28 are connected by an oil passage 35.
The solenoid valve 18 and the solenoid valve 28 are connected by an oil passage 36. Also, the hydraulic pump 33 is driven by the rotation of the engine E, and the hydraulic oil in the tank 37 is pressure-fed to the total hydraulic controller 31 through the oil passage 38. This hydraulic pressure is controlled by the relief valve 39, and the oil passage 3
The oil discharged from the hydraulic pump 33 is configured to return from the oil passage 40 to the tank 37 when the hydraulic pressure of the hydraulic pressure 8 exceeds a certain pressure.

FIG. 2 is a block diagram of a four-wheel steering control device, in which the sensors for detecting the steering angles of the front wheels and the rear wheels, the control lever sensor for raising and lowering the working machine, and the lower link lift sensor are A / It is connected to the input interface via the D converter. Further, a push button switch and an automatic control mode switch for manually switching each of the front wheel steering mode, the rear wheel steering mode, and the four-wheel steering mode are directly connected to the input interface. Various input signals input to the input interface are arithmetically controlled in the CPU, and processing corresponding to each steering mode is performed. Then, various signals are output via the output interface, the lamp corresponding to the steering mode is turned on, and the solenoid is operated to switch each solenoid valve.

FIG. 3 is a conceptual diagram showing the turning operation of the control lever for raising and lowering the working machine. If the control lever is turned on by operating the working machine from the control lever off position A to the raising position, first, The steering mode becomes the front wheel steering mode. And under the automatic control mode,
When the control lever is operated to a position higher than the predetermined value B, the steering mode is automatically switched to the four-wheel steering mode. As will be described later, the PL flag is off until the control lever reaches the B position (hereinafter referred to as PL = on), and when the control lever is rotated above the B position, the PL flag is turned on (hereinafter referred to as PL = on). PL = off).

FIG. 4 shows the state transition of the automatic control mode of the four-wheel steering control according to the present invention. The BS flag is turned off (hereinafter referred to as BS = off) when the shift lever is at the forward position. Therefore, the BS flag is turned on (hereinafter referred to as BS = on) when the shift lever is operated to the reverse position. Further, when the control lever for lifting and lowering the working machine is operated to turn on the control lever, and the control lever is further turned to the raised position and the front wheel steering mode is switched to the four-wheel steering mode, the PL flag is turned on (PL = on).

First, after the automatic control mode switch is set to the automatic control mode, when the speed change lever is moved to the forward position and the machine body is moved forward, BS = off: PL = of
Since it is f, the front wheel steering mode is set. Here, as described above, when the control lever is operated to the raised position above the predetermined value, BS = off: PL = on, and the four-wheel steering mode is automatically switched. The steering mode becomes the four-wheel steering mode even when the control lever is in the above state immediately after the automatic control mode switch is turned on. Then, when the control lever is returned to the predetermined value or less, the control returns to the front wheel steering mode.

On the other hand, when the gear shift lever is operated to the reverse position in the front wheel steering mode, BS = on, so P
The steering mode is automatically switched to the rear wheel steering mode regardless of whether the L flag is on or off. Of course, immediately after the automatic control mode switch is turned on, even when the shift lever is in the reverse position, BS = on and the rear wheel steering mode is set. Even in the four-wheel steering mode, when the shift lever is operated to the reverse position, BS = on and the steering mode is switched to the rear wheel steering mode.

In the rear wheel steering mode, when the shift lever is operated to the forward position and the control lever is operated, BS = off: PL = on, so the mode is switched to the four-wheel steering mode. Further, in the rear wheel steering mode, if the gear shift lever is operated to the forward position and the control lever is turned off, BS = off: PL =
Since it is off, it returns to the front wheel steering mode.

Thus, in the automatic control mode, the steering mode is determined by the operating position of the control lever and the operating position of the shift lever. However, even in the automatic control mode, when the push button switch for manual switching is operated, the manual priority control mode is provided so as to forcibly switch to the steering mode of the operated push button switch. The manual priority control mode can be switched to any steering mode by operating the push button switch in any steering mode. Then, when the steering mode of the automatic control mode determined by the operation position of the control lever and the operation position of the speed change lever and the steering mode in the manual priority control mode match, the manual priority control mode is released. Control to return to the automatic control mode.

FIG. 5 is a flow chart of the above-described four-wheel steering control of the present invention. First, after the manual priority control mode is set (step 101), the flag f is set to 0 (step 102). If the switch in the automatic control mode is not on, the process returns to step 101. If the switch is on, the process proceeds to the next step to enter the automatic control mode (steps 103 to 104). In step 104, the f flag is monitored, and when f = 0, the process proceeds to step 105,
When f = 1, the process proceeds to step 106.

In step 105, the BS flag and the PL flag are monitored, and if the operation angle of the control lever is small, B
When S = off: PL = off, the front wheel steering mode is set (step 107), when the operation angle of the control lever exceeds a predetermined value, and when BS = off: PL = on, the four-wheel steering mode is set (step 107). 108).
Further, regardless of the operation position of the control lever, when the shift lever is set to the reverse position and BS = on: PL = on or off, the rear wheel steering mode is set (step 109).

Then, the flag f is set to 0, and it is judged whether or not the push button switch for manual switching is ON (steps 110 to 111). Here, if the push button switch is off, the process returns to step 105 and the automatic control mode is continued. On the other hand, when the push button switch for manual switching is turned on, the steering mode of the push button switch operated at that time is stored in the memory as Mw, and the flag f is set to 1 (steps 112 to 113). In such a case, the manual priority control mode is set, and the push button switch that has been operated is switched to the steering mode (step 114). After returning to step 104, since the flag f = 1 is set, the routine proceeds to step 106.

In step 106, it is judged whether or not the push button switch for manual switching is turned on. When the push button switch is turned off, the process returns to step 104. on the other hand,
When the push button switch is turned on, the steering mode of the push button switch at that time is compared with the steering mode Mw stored in the memory in step 112 (step 11).
5). When both steering modes match, the flag f is set to 0.
(Step 116), the manual priority control mode is canceled via Step 114, and the automatic control mode is restored. If the two steering modes do not match, the steering mode of the push button switch operated later is switched to (step 114).

The present invention can be modified in various ways without departing from the spirit of the present invention, and it goes without saying that the present invention extends to such modifications.

[0024]

As described in detail in the above one embodiment, the present invention is provided with the manual priority control mode in which when the push button switch for manual switching is operated in the automatic control mode, it is switched to the operated steering mode. Then, in the manual priority control mode, when the steering mode determined by the automatic control mode and the steering mode operated by the push button switch match, the manual priority control mode is canceled and the automatic control mode is restored. Can operate in any steering mode without considering which steering mode the aircraft being operated is in.

Therefore, it is possible to arbitrarily select the automatic control mode or the manual control mode depending on the shape of the farm field and the working mode, which eliminates the discomfort in operation and contributes to the improvement of safety and working efficiency. it can.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of a four-wheel steering control device provided in a power vehicle.

FIG. 2 is a block diagram of a four-wheel steering control device.

FIG. 3 is a conceptual diagram showing a rotating operation of a control lever for raising and lowering a work machine.

FIG. 4 is a conceptual diagram showing a state transition in an automatic control mode.

FIG. 5 is a flowchart of four-wheel steering control.

[Explanation of symbols]

 11 front wheels 14,24 steering cylinders 18,28 solenoid valves 21 rear wheels

Claims (1)

[Claims] 1. A four-wheel steering mode in which a steering cylinder is provided for each of the front and rear wheels, a solenoid valve is switched to extend and retract the front and rear steering cylinders, and both front and rear wheels are steerable, The operating position of the control lever and the gear shift are set so that the four-wheel steering mode is set when the control lever for raising and lowering the work implement is operated to a position higher than a predetermined value, and the rear wheel steering mode is set when the shift lever is operated to the reverse position. In a four-wheel steering control device having an automatic control mode that determines the steering mode depending on the lever operating position, when the pushbutton switch for manual switching is operated in the automatic control mode, the steering mode of the operated pushbutton switch A manual priority control mode for switching to the above is further provided, and the steering mode in the manual priority control mode and the steering mode determined by the automatic control mode The four-wheel steering control device is characterized in that the manual prioritized control mode is canceled and the automatic control mode is restored when the two match.