JPH05147555A - Four-wheel steering device for power vehicle - Google Patents

Abstract

PURPOSE:To enable mode change to be made simply at an edge of rice field ridge in a power vehicle with an automatic steering mode by providing the vehicle with a control means by which changeover to a set mode is made possible through cancellation of automatic mode made by operation of one mode setting switch. CONSTITUTION:When an engine of a tractor is started, a front steering mode is selected. At this time changeover is made to a manual mode by pressing an automatic/ manual changeover switch S4 and thereafter the steering mode determined by pushing the switch is obtained. In the case of automatic mode selected, when a working vehicle is raised at a front wheel steering mode, changeover is made to a front/rear wheel reverse phase steering mode, and when the vehicle is lowered without pushing any switch, changeover is made (resumed) to the front wheel steering mode. When any of switches, that is, a front wheel steering switch S1, front and rear steering switch S2 and rear wheel steering switch S3 is pushed during the raising operation of the vehicle, the front/rear wheel reverse phase steering mode is canceled and thus a selected steering mode is carried out. It is thus possible to simplify the steering mode changeover when a working vehicle is raised at an edge of ridge in a rice field.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering system used in a power vehicle such as a tractor and a passenger management machine, and more particularly to a steering system capable of steering front wheels and rear wheels independently or in association with each other. The purpose is to get.

[0002]

2. Description of the Related Art The applicant has already proposed a steering device in which front wheels and rear wheels can be independently steered. This device consists of a front wheel steering mode that steers only the front wheels, a rear wheel steering mode that steers only the rear wheels, and a front and rear wheel antiphase steering mode in which the front and rear wheels are steered in opposite directions. In the manual mode, the operation is performed by selecting one of the three setting switches.
The operator can select the desired steering mode, and in the automatic mode, for example, when the working machine is raised before turning, the front and rear wheel antiphase steering is forced from the selected steering mode. When the mode is changed to the working mode and the working machine is lowered, the original steering mode is restored again.

[0003]

By the way, in such a conventional apparatus, when the working machine is raised and turned at the edge of the ridge in the automatic mode, the front and rear wheel antiphase steering mode is set at the time when the working machine is raised. Therefore, when releasing this to shift to another steering mode, first lower the work implement and then operate the switch that is about to be set, or reverse phase of the front and rear wheels. In order to release the steering mode, the front and rear wheel anti-phase steering switches must be operated again, and then the steering switch to be set must be operated.This kind of operation is troublesome and steering with a normal tractor is difficult. Since the senses are different, an unfamiliar operator has a problem of being confused without knowing which switch should be operated.

[0004]

The present invention has been proposed to solve the above-mentioned problems, and has taken the following technical means. That is, a front wheel steering mode, a front-rear wheel antiphase steering mode, and a rear wheel steering mode are provided, and a desired steering mode can be selected by operating each setting switch, and a working machine connected to the machine body. In a power vehicle with an automatic steering mode which is interlocked so as to preferentially shift from the selected steering mode to the front-rear wheel antiphase steering mode when the vehicle is raised. A four-wheel steering system for a powered vehicle is provided with a control means for releasing the automatic steering mode by operating the mode setting switch, and shifting to the steering mode of the operated setting switch. is there.

[0005]

Embodiments of the present invention will now be described based on the embodiments shown in the drawings. First, the structure will be explained as follows.
Is a tractor for passenger management, which is provided with front wheels 2, 2 and rear wheels 3, 3 at the front and rear portions of the body, and these front and rear wheels 2, 3 can be steered individually or in conjunction with each other. Has been done.

A vertical axis type engine 5 is provided in the bonnet 4 of the tractor 1, and the transmission case 7 transmits the rotational power of the engine 5 via a power transmission means 6 including a pulley and a belt. To the internal gearbox. FIG. 4 is a hydraulic circuit diagram of the front wheel steering system F and the rear wheel steering system R, the details of which will be described below. 30 and 30 are front wheels 2 and 2.
In this knuckle arm, both knuckle arms 30, 30 are connected by a tie rod 31.

Reference numerals 33 and 33 are knuckle lures of the rear wheels 3 and 3.
Reference numerals 35 and 35 are tie rods for connecting the knuckle arms 33, 33. The arm 37 provided above the knuckle arm 30 of the right front wheel 2 and the center of the lower part of the machine are connected by a single rod hydraulic cylinder 40, and the front part of the knuckle arm 33 of the right rear wheel 3 and the machine body. A hydraulic cylinder-44 is interposed between and.

Reference numerals 45 and 46 are steering angle sensors for detecting the steering angles of the right front wheel 2 and the rear wheel 3. 50 is a front wheel steering system F
It is an electromagnetic valve that controls the two-position, four-port type valve, and normally includes the hydraulic pump 52 side and the hydraulic cylinder-4.
When the solenoid 53 of the solenoid valve 50 is energized and the solenoid valve 53 is in communication with the 0 side, the chamber is switched to the right side and the oil passage between the hydraulic pump 52 side and the hydraulic cylinder 40 side is cut off.

Reference numeral 55 is an electromagnetic valve for controlling the rear wheel steering system R, which is composed of a 2-position 4-port type valve, and normally disconnects the hydraulic pump 52 side and the hydraulic cylinder 44 side from each other. When the solenoid 58 is energized, the chamber is switched to the right chamber, and the hydraulic pump 52 side and the hydraulic cylinder-4 are connected.
The oil passages on the 4th side are in communication. Reference numeral 60 denotes an all-hydraulic steering mechanism. When the steering handle 61 is turned, the oil passage and the oil amount are controlled.

For example, in the figure, when the steering handle 61 is turned to the right, the operating pressure oil sent from the hydraulic pump 52 passes through the oil passage (a) into the chamber on the left side of the electromagnetic valve 50, and the hydraulic cylinder-- The piston rod of 40 is pushed out to cut the front wheels 2 and 2 to the right, and the returned working pressure oil returns to the tank 63 through the chamber on the left side of the electromagnetic valve 55. On the contrary, when the steering handle 61 is turned to the left, the operating pressure oil sent from the hydraulic pump 52 passes through the oil passage (b) into the left chamber of the electromagnetic valve 55 and retracts the piston rod of the hydraulic cylinder-40. Then, the front wheels 2 and 2 are turned to the left, and the returning pressure oil is collected in the tank 63.

Reference numeral 65 is a valve for controlling the lifting and lowering of a working machine connected to the rear part of the tractor-1 and is composed of an ascending proportional control valve 65a and a descending proportional control valve 65b. Reference numeral 66 denotes a position operation lever, and a position setting device 68 is provided at the rotation base of the operation lever 66. Work machine connection link 1 with a hitch at the rear
The lower portion of the front end of the rotary body 8 is rotatably supported by the lower rear portion of the machine body, and the connecting link 18 is rotated up and down by two single-acting hydraulic cylinders 21 and 21. A position detector 69 for detecting a rotation angle is provided at a pivot portion of the connecting link 18.
Is provided.

Therefore, when the position operating lever 66 is rotated to set the hoisting height of the working machine, the connecting link 18 is rotated until it coincides with the set value, and the position control system is constructed there. To be done. The valve 6
In the ascending proportional control valve 65a or the descending proportional control valve 65b, a current substantially proportional to the difference between the set value by the position operation lever 66 and the detected value by the position detector 69, that is, the deviation is passed. The flow rate is controlled substantially in proportion to the deviation.

Further, the position operation lever 6 shown in FIG.
The lever guide portion 22 of No. 6 is provided with a raising position setting dial 72 for setting the maximum raising position of the connecting link 18, and is configured so that the working machine moves up and down with the height determined by the dial 72 as the maximum raising position. is doing. In this embodiment, as shown in FIG. 5, the raising position setting dial 7
According to the setting of 2, the position setting of the position operation lever 66 is reread. That is, when the set value of the position operation lever 66 is displaced within the range of 0.5 V to 5 V in voltage and the raising position setting dial 72 is also changed within the range of 0.5 V to 5 V, If the raising position setting dial 72 is set to, for example, the intermediate V1 (position of 4 volts), the position operation lever 66
Even if is rotated to the maximum raised position, the work implement is raised only to the height set as V1. In other words, if the raising position setting dial 72 is not set to the maximum raised position but only set to a height in the middle, the work implement will not move to the maximum raised position even if the position operation lever 66 is moved back and forth to full stroke. Since the position operation lever 66 can be operated by a full stroke, fine adjustment is possible as a result, and operability is improved.

In the tractor 1, the front wheels 2, 2 and the rear wheels 3, 3 can be steered together, and the solenoids 53, 58 of the electromagnetic valves 50, 55 are turned on and off as follows. By controlling in combination, three steering modes can be selected. That is, in the off state where neither solenoid 53, 58 is energized, the front wheel steering mode is set, and when both solenoids 53, 58 are turned on, the rear wheel steering mode is set, and the solenoid 53 is off and the other solenoid is turned on. When 58 is turned on, the front and rear wheels 2 and 3 are switched to the front and rear wheel antiphase steering mode in which they are oriented in opposite directions.

These modes are switched by a mode selector switch provided in the vicinity of the cockpit, and the front wheels 2, 2 and the rear wheels 3, 3 are switched in a straight state when switching between the modes. It is configured to be able to switch when it becomes. FIG. 6 shows a block circuit of this control device. Operation panel 7
0 mode switch, namely, front wheel operation switch S1, front / rear wheel anti-phase steering switch S2, rear wheel steering switch S3, and automatic / manual switch S4 are CPUs via an input interface 82. Control section 83 consisting of
And the control signal is connected to the output interface 84.
And is connected to the solenoids 53 and 58 via the solenoids, and the solenoids 53 and 58 are excited independently or in conjunction with each other to obtain a desired steering mode.

Front wheel steering angle sensor-45, rear wheel steering angle sensor-46, position setter 68, position detector 6
9 and raising position setting dial 72 are A / D converter 85
Is connected to the input interface 82 via. In addition to the steering solenoids 53 and 58, the output interface 84 includes an ascending proportional control valve 65a, a descending proportional control valve 65b, a front wheel steering display lamp L1, and a front and rear wheel reverse phase steering display lamp L2. A rear wheel steering display lamp L3 and an automatic mode display lamp L4 are connected.

The flow chart shown in FIG. 7 shows the contents of the control program for changing from the automatic mode to the manual mode to the desired steering mode. explain. When the key switch of the riding management tractor-1 is turned on to start the engine 5, the front wheel steering mode is selected for safety reasons (step #
1). When the automatic / manual switch S4 is pressed to select the manual mode and then one of the three switches S1, S2 and S3 is pressed, the steering mode of the pressed switch is executed. When the automatic mode is selected (step # 2) and the work implement is raised in the front wheel steering mode, the front wheel steering mode is switched to the front and rear wheel antiphase steering mode ( Step # 4, Step # 6). here,
When none of the switches S1, S2 and S3 are operated and the working machine is lowered, the mode returns to the front wheel steering mode again (step # 11). When any one of the front wheel steering switch S1, the front and rear wheels reverse phase steering switch S2, and the rear wheels steering switch S3 is pressed while the work implement is raised, the front and rear wheels reverse phase steering mode is released and the selected steering mode is selected. -The command is executed.

Next, the operation of the flow chart of FIG. 8 will be briefly described. The riding management tractor 1 described in the above embodiment is configured so that the position control lever 66 can perform position control. However, the riding management tractor-1 includes a position control. There is also a type without a function, and the flow chart shown in FIG. 8 is configured so that the steering mode can be changed in any form. That is, this control is characterized in that the CPU automatically discriminates whether or not it is the position control specification when the key switch is turned on.

In the case of the riding management tractor-1 which does not have the position control specification, the position operation lever 66 is used.
In place of the above, a normal hydraulic operation lever is provided beside the seat, and it is configured to detect that the working machine is lifted by a working machine lift detection switch (not shown) provided at the rotation base of the connecting link 18. is doing. As is clear from this flow chart, both the values of the position setter 68 and the position detector 69 are 0 depending on whether the position control specification is used or not.
It is determined by whether it is a bolt.

Position control specification tractor
Since both the position setting value and the position detection value do not become 0 volt, if both values are not 0 volt when the key switch is turned on, it is judged as the position control specification and both values are determined. When is 0 volt, it is judged as a normal tractor. Further, the steering mode is switched by the position detector 68 in the position control specification, and in the specification without the position, the steering mode is switched when the work implement rise detection switch detects the rise of the work implement. Conventionally, a method has been adopted in which the input port of the controller is provided with a model or an input port for the specification determination to determine the specifications, and the detection line is short-circuited or opened on the harness. However, in such a conventional method, the cost increases as the input port of the controller increases.

However, in the above-mentioned improved device, when the key switch is turned on, the CPU reads the values of the position detector 69 and the position setter 68 to automatically determine the specifications, and controls according to the specifications. Since the program is executed, the input port is not required and the cost is low.

[0022]

As described above, the present invention provides the front wheel steering mode.
Equipped with front, rear wheel anti-phase steering mode, rear wheel steering mode,
By operating each setting switch, the desired steering mode
With the automatic steering mode that is interlocked so that when the working machine connected to the machine is raised, the selected steering mode preferentially shifts to the front-rear wheel antiphase steering mode. In a motor vehicle, when any one of the mode setting switches is operated, the automatic steering mode is released, and a control means for shifting to the steering mode of the operated setting switch is provided. The switching of the steering mode when the working machine is lifted is simpler and easier than the conventional method, and has a feature that the transition to the next steering mode can be performed quickly.

[Brief description of drawings]

FIG. 1 is a side view of a riding management tractor.

FIG. 2 is a perspective view of an operation panel portion.

FIG. 3 is a perspective view of a position operation lever guide portion.

FIG. 4 is a hydraulic circuit diagram showing the operating principle.

[Fig. 5] Raising position setting dial and position operation lever
It is a figure explaining the relationship with.

FIG. 6 is a block diagram showing a control system.

FIG. 7 is a flowchart.

FIG. 8 is a flowchart.

[Explanation of symbols]

 1 tractor 2 front wheel 3 rear wheel 4 bonnet 18 connecting link 21 lift cylinder-40 hydraulic cylinder-44 hydraulic cylinder-45 steering angle sensor-46 steering angle sensor-66 position operation lever 68 position setter 69 position detector S1 front wheel Steering switch S2 Front / rear wheel anti-phase steering switch S3 Rear wheel steering switch S4 Automatic / manual switch

Claims (1)

[Claims] 1. A front wheel steering mode and a front and rear wheel antiphase steering mode.
It is equipped with a rear wheel steering mode and a rear wheel steering mode, and a desired steering mode can be selected by operating each setting switch, and when the working machine connected to the machine body is raised, the selected steering mode is given priority. In a power vehicle with an automatic steering mode that is interlocked to shift to the front-rear wheel anti-phase steering mode, when any one of the mode setting switches is operated, the automatic steering mode is released, A four-wheel steering system for a power vehicle, comprising control means for shifting the operated setting switch to a steering mode.