JPH0616147A - Steering device in motive power vehicle - Google Patents

Abstract

PURPOSE:To facilitate turning operation on the edge of a ridge between rice fields by constituting height of a working machine raising and lowering link so as to become different when being put in a front and rear wheel opposite-phase steering mode in an automatic steering mode and when being restored to a front wheel steering mode from the opposite-phase steering mode. CONSTITUTION:When being put in a front wheel steering mode in an automatic steering mode, and when a lift cylinder 21 is operated and a connecting link 18 is raised, the height is detected by a sensor 84. When an angle theta of the connecting link exceeds theta1, a mode is switched to a front and rear wheel opposite-phase steering mode, and this becomes control when a operation lever is operated to the rising side to raise a working machine. After the working machine is raised and reaches prescribed height theta3, the working machine is lowered, and when the angle becomes smaller than prescribed theta2, the mode is restored to the front wheel steering mode. This becomes control when a machine body transfers to forward movement after turning is finished. In this way, when the working machine is lifted up, the mode is immediately put in the front and rear opposite-phase steering mode, and it turns at the minimum radius, and after the turning is finished, the working machine is transferred to the former front wheel steering mode when the working machine starts to be lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering device for a power vehicle in which front and rear wheels can be steered independently or in association with each other.

[0002]

2. Description of the Related Art Conventionally, a device of this type is constructed such that the front and rear wheels can be independently steered, and in the manual mode, one of the modes selected by the operator, for example, the front wheel steering mode. −
When the manual mode is switched to the automatic mode, the lifting operation of the work machine is enabled by preferentially using the reverse mode steering mode in which the front and rear wheels face in opposite directions. There is a front-rear wheel anti-phase steering mode in which the front and rear wheels face in opposite directions in cooperation with each other, and a mode in which the front-rear wheels are switched to the rear-wheel steering mode in conjunction with the reverse operation of the body.

[0003]

In the case of the above-mentioned conventional apparatus, when the working machine is lifted in the automatic mode, the front wheel steering mode is set.
When the working machine is lowered and the anti-phase steering mode is released, the anti-phase steering mode is released and the original front wheel steering mode is restored again. Conventionally, the timing of such a mode change is controlled by turning on and off a single micro switch, so that it is performed at the same position when the anti-phase steering mode is set and when it is released. Therefore, there was a problem that the operability at the edge of the ridge deteriorates.

More specifically, when turning at the ridge, in order to reduce the turning radius, it is preferable that the front and rear wheels are in the opposite phase steering mode in which the front and rear wheels face in opposite directions, and the mode of that mode is reversed. It is better that the switching be done earlier in conjunction with the lifting operation of the work implement. On the other hand, after turning, it is better to shift to steering with only the front wheels so that the wheels do not collapse on the ridges, so the mode returns to the original front wheel steering mode before the work implement is completely lowered. It is better to do.

[0005]

The present invention has been proposed to solve the above-mentioned problems, and has taken the following technical means. That is, in addition to the front wheel steering mode,
It has at least front and rear wheel anti-phase steering mode, and the steering mode is set between the front wheel steering mode and the front and rear wheel anti-phase steering mode in association with the manual mode setting and the lifting operation of the work implement. In a power vehicle equipped with an automatic steering mode that automatically switches, and a lifting link for connecting a working machine to the rear of the machine body, front-rear wheel antiphase steering mode in automatic steering mode is used. And a height of the work implement lifting link at the time of becoming different from the height at the time of returning from the front-rear wheel anti-phase steering mode to the original front wheel steering mode. Is.

[0006]

Embodiments of the present invention will be described below 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 ordinate type engine 5 is provided in the hood 4 of the tractor 1, and the transmission case 7 transmits the rotational power of the engine 5 through a power transmission means 6 including a pulley and a belt. To the internal gearbox. At the rear of the mission case 7, two power take-off shafts 9 and 10 are provided.
Is mounted on the PT, and the upper take-out shaft 9 is provided with a PT projecting forward from the transmission case 11 via a universal joint 12.
It is transmitted to the O input shaft 14.

In the rear part of the transmission case 11, the rearward P
The TO shaft 15 is mounted on a protruding shaft, and the PTO shaft 15 is used as a power take-off shaft for driving a working machine such as a rotary connected to the rear part of the machine body. Reference numeral 18 denotes a connecting link for raising and lowering the working machine, which is vertically rotated by two lift cylinders 21 and 21 provided at the rear ends of the left and right frames 20. Reference numeral 84 is a height detecting sensor attached to the pivoting support of the connecting link 18 for detecting the raised position of the working machine.

The rotational power decelerated by the transmission in the transmission case 7 is transmitted to the front axle housing 25.
And via a differential device (not shown) in the rear axle housing 28 to the front wheels 2, 2 and the rear wheels 3, 3, respectively. Reference numeral 29 is a change lever, and a switch 85 for detecting that the machine body is operated in reverse is provided on the operation base of the change lever.

Next, the front wheel steering system F and the rear wheel steering system R will be described based on the hydraulic circuit diagram shown in FIG. 30 and 30 are knuckle arms for the front wheels 2 and 2, both knuckle arms 30 and 3.
0s are connected by a tie rod 31. 33 and 33 are knuckle arms of the rear wheels 3 and 3, 35 is knuckle arm 3
It is a tie rod that connects 3, 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 two-position four-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 excited, 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 4 side communicate. 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 main control valve for controlling the lifting and lowering of a working machine connected to the rear of the tractor-1.
It is possible to switch between "neutral position", "up position", and "down position". If the operator holds the hydraulic operation lever 66 and keeps it at the "raised position", the operating pressure oil flows into the lift cylinders 21 and 21, and the connecting link 18 is rotated upward. Each solenoid 5 of the electromagnetic valves 50 and 55 described above
Three steering modes can be selected by controlling the ON / OFF of 3, 58 as follows.

That is, in the OFF state where neither solenoid 53, 58 is energized, the front wheel 2 and 2 steering modes are set, and when both solenoids 53 and 58 are turned on, the rear wheel steering mode is set and the solenoid 53 is set. Is off and the other solenoid 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 switching switch 68 provided near the cockpit, and the switching between the modes is performed by the front wheels 2, 2 and the rear wheels 3.
It is configured so that it becomes possible when 3 is in a straight traveling state.

As will be described later, this steering device is a manual steering motor.
In the manual steering mode, the steering mode set by the operator is prioritized. In the automatic steering mode, when the working machine is raised, the steering mode changes to the front-rear wheel antiphase steering mode, and when the machine body is moved backward, the steering mode shifts to the rear wheel steering mode. Next, the control system of FIG. 3 will be described.
Steering angle sensors 45 and 46 for detecting the steering angles of the front wheels 2 and 2 and the rear wheels 3 and 3 are connected to a control unit 74 including a microcomputer via an A / D converter 70 and an input interface 72. ing.

The input interface 72 also includes:
Front wheel steering setting switch S1, rear wheel steering setting switch S
3, front and rear wheel reverse phase steering setting switch S2, automatic-manual changeover switch S4, working machine lift height detection sensor-84,
A reverse detection switch 85 of the machine body is connected. on the other hand,
The output interface 76 has a front wheel steering indicator lamp L.
1, rear wheel steering display lamp L2, front and rear wheel anti-phase steering display lamp L3, automatic mode display lamp L4 and solenoid valve 5
The 0, 55 solenoids 53, 58 are connected.

The contents of the program shown in FIG. 4 are stored in the memory of the control unit 74, and the contents will be described below. In the description, the relationship between the connecting link 18 of FIG. 5 and the timing of switching the steering mode will be briefly described. In this embodiment, the angle when the connecting link 18 is at the lowest position is θ = 0, and the highest position is the highest position. Θ =
Let θmax.

It is assumed that the connecting link 18 moves up and down within this range. When the connecting cylinder 18 is lifted up to θ = θ1 by operating the lift cylinder -21 to raise the working machine at the edge, the automatic steering mode is set. When the vehicle is in the front wheel steering mode, the mode is switched to the front and rear wheel antiphase steering mode. The work machine is raised to the top and stopped, but the angle when stopped slightly before this is set to θ = θ3 without raising it to the top, and the work machine was stopped in the automatic steering mode. The angle when the vehicle is lowered to switch from the front-rear wheel antiphase steering mode to the front-wheel steering mode is θ = θ2. (Here, .theta.2 = .theta.3-.alpha ..) When the key switch of the riding management tractor-1 is turned on, the front wheel steering mode is set. Here, the steering mode is the manual steering mode. Is selected, the steering mode selected by the operator is set (steps 1, 2, 11).

When the operator pushes the automatic / manual switch S4 to switch to the automatic steering mode, the connecting link 1
The value of θ is read in order to detect the height of 8, and if the value of θ is larger than θ1, the front wheel steering mode is switched to the front / rear wheel antiphase steering mode (steps 3, 4,
5). This is the control when the hydraulic operation lever 66 is operated to the "up" side in order to raise the working machine at the edge of the ridge.

The working machine rises to the height designated by the hydraulic operation lever 66 and stops, but the angle .theta.3 at that time is read and the height at which the mode is released, that is, Value θ obtained by subtracting the constant angle α from θ3
2 is calculated (step 6). If .theta.2 is larger than .theta.1, the angle .theta. Of the connecting link 18 is read again, and when the value becomes smaller than .theta.2, the anti-phase steering mode is restored to the front wheel steering mode (step). 7,
8, 9, 12). This is control when the aircraft finishes turning and again advances the aircraft along the ridges.

As described above, in this embodiment, as soon as the working machine is lifted, the front wheel steering mode is switched to the antiphase steering mode in which the front and rear wheels face in opposite directions.
It can be turned with the minimum turning radius, and after turning, the antiphase steering mode is changed to the front wheel steering mode at the time when the connecting link 18 starts slightly lowering without lowering the working machine to the original height. Since the transition is made, it is possible to smoothly steer the aircraft without causing a problem that the rudder is excessively cut and the ridge is collapsed.

In this embodiment, during the automatic steering mode,
When the automatic / manual switch S4 is pressed, the manual steering mode is
It is configured to return to normal mode. Next, the flow chart of FIG. 6 will be briefly described. The tractor 1 for passenger management described above preferentially switches from the previous steering mode to the rear wheel steering mode when the vehicle body is retracted in the automatic steering mode. It was not possible to switch to the anti-phase steering mode. That is, in the case of the conventional device, when changing the rear wheel steering mode from the rear wheel steering mode to the front and rear wheel antiphase steering mode, the change lever 29 is set to the neutral position, or It was necessary to operate in the forward drive range and then press the front / rear wheel antiphase steering mode setting switch S2.

However, according to this improved program,
The front wheel steering mode was set because the aircraft was retracted in the automatic steering mode.
Even if the steering mode is switched from the rear wheel steering mode to the rear wheel steering mode, the release lever 29 does not need to be released, and the switch S2 is immediately switched to the front and rear wheel antiphase steering mode (steps 9 and 10). ). For this reason, even in the reverse drive state, it is possible to turn the aircraft in a small radius without taking time at the edge.

Next, the flow chart of FIG. 7 will be described. As described above, the tractor-1 described in this embodiment shifts to the rear wheel steering mode when the vehicle body is retracted during the automatic steering mode, and shifts to the front wheel steering mode when the vehicle body is moved forward. However, in the flow chart shown in FIG. 7, even when the operation of advancing the machine body is performed, when the working machine connected to the machine body is lifted, the front wheel steering motor is operated.
The front-wheel steering mode (steps 3, 4, and 5) is set only when the working machine is descending, and the front and rear wheels are set to the opposite-phase steering mode in which the front and rear wheels face in opposite directions without shifting to the mode. 7). The switch S5 described in the chart in the figure is a switch for detecting whether or not the working machine has been lifted to a predetermined height.

By changing to such a control program, the operability at the edge is significantly improved. Next, the flow chart of FIG. 8 will be described. The feature of this control program is that, in the automatic steering mode, when the working machine is raised, even if the reverse phase steering mode setting switch S2 is pushed to cancel the reverse phase steering mode, That's why I couldn't do it. In the case of the conventional device, when the tractor-1 is moved forward in the automatic steering mode, the front wheel steering mode is prioritized, and the front and rear wheel antiphase steering mode is automatically switched only when turning at the ridge. I am trying to replace it,
In order to cancel the front-rear wheel anti-phase steering mode in the automatic steering mode, the operator must first lower the work implement to the ground or press the anti-phase steering mode setting switch S2. However, if an unfamiliar operator mistakenly operates this, the maneuverability of the machine body may deteriorate. That is, when the working machine is raised, the turning radius is smaller and the steerability is better in the front-rear wheel antiphase steering mode in which the front-rear wheels are directed in opposite directions. However, if the operator mistakenly presses the setting switch S2 during turning, the aircraft will start to turn along a trajectory different from the one intended by the operator, and as a result, the rear wheels will have a ridge. There is a risk of problems such as stepping down.

The content of the control program shown in the flow chart of FIG. 8 is that the front and rear wheel reverse phases are always maintained while the work implement is raised so that such a problem does not occur, regardless of the ON / OFF operation of the switch S2. The steering mode is maintained. Finally, an improved structure of the front axle portion of the tractor-1 described in this embodiment will be described with reference to FIGS. 9 to 11. In the figure, reference numeral 94 is the left and right frames 2
A reinforcing plate connecting 0 and 20 together, reference numeral 96 shown in FIG. 10 is a spacer interposed at the outer end portion of the front axle housing 25, and this spacer lengthens the tread of the front axle portion. To be installed in case. When the tread is lengthened, the length of the hydraulic cylinder 40 for steering must be adjusted. In this example, however, the length of the piston rod 98 is changed to accommodate it.

That is, the mounting position of the hydraulic cylinder 40 itself is not changed, and another extension rod 99 is interposed between the piston rod 98 and the knuckle arm 30 so that they are screwed and screwed together to form a tread. Configured to accommodate changes. Since the rear wheel tread is changed and adjusted in the same manner as the front wheel, the description thereof will be omitted.

[0029]

As described above, the present invention has at least the front and rear wheel antiphase steering mode in addition to the front wheel steering mode, and is interlocked with the manual mode setting and the lifting operation of the working machine. Equipped with an automatic steering mode in which the steering mode is automatically switched between the front wheel steering mode and the front-rear wheel anti-phase steering mode, and further equipped with an elevating link for connecting the working machine to the rear part of the machine body. In a powered vehicle, the height of the work equipment lifting link when the front-rear wheel anti-phase steering mode is set in the automatic steering mode, and the original front-wheel steering mode is restored from the front-rear wheel anti-phase steering mode. Since the heights are different at the time of turning, when the working machine is raised at the ridge and the turning operation is started, it is immediately switched to the front-rear wheel anti-phase steering mode and a small turn can be made. When the work implement started to descend, switch to the original front wheel steering mode. Since Erareru, without such disturbing stepping in rear wheel ridges, the operability is remarkably improved.

[Brief description of drawings]

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

FIG. 2 is a hydraulic circuit diagram for explaining the operating principle.

FIG. 3 is a block diagram showing a control system.

FIG. 4 is a flowchart for explaining the contents of control.

FIG. 5 is a diagram illustrating the relationship between the height of a connecting link and the timing of mode switching.

FIG. 6 is a flowchart for explaining the control contents of the improvement device.

FIG. 7 is a flowchart for explaining the control contents of the improvement device.

FIG. 8 is a flowchart for explaining the control contents of the improvement device.

FIG. 9 is a plan view showing a structure of a front axle portion.

FIG. 10 is a plan view of the front axle portion after changing the tread.

FIG. 11 is a cross-sectional view of a main part.

[Explanation of symbols]

 1 riding management tractor-2 front wheel 3 rear wheel 4 bonnet 5 engine 18 connecting link 21 lift cylinder-25 front axle housing 40 hydraulic cylinder-44 hydraulic cylinder-45 steering angle sensor-46 steering angle sensor-

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 30, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

[0029]

As described above, the present invention has at least the front and rear wheel antiphase steering mode in addition to the front wheel steering mode, and is interlocked with the manual mode setting and the lifting operation of the working machine. Equipped with an automatic steering mode in which the steering mode is automatically switched between the front wheel steering mode and the front-rear wheel anti-phase steering mode, and further equipped with an elevating link for connecting the working machine to the rear part of the machine body. In a powered vehicle, the height of the work equipment lifting link when the front-rear wheel anti-phase steering mode is set in the automatic steering mode, and the original front-wheel steering mode is restored from the front-rear wheel anti-phase steering mode. Since the heights are different at the time of turning, when the working machine is raised at the ridge and the turning operation is started, it is immediately switched to the front-rear wheel anti-phase steering mode and a small turn can be made. When the work implement started to descend, switch to the original front wheel steering mode. Since Erareru, without such disturbing stepping in rear wheel ridges, the operability is remarkably improved.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

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

FIG. 2 is a hydraulic circuit diagram for explaining the operating principle.

FIG. 3 is a block diagram showing a control system.

FIG. 4 is a flowchart for explaining the contents of control.

FIG. 5 is a diagram illustrating the relationship between the height of a connecting link and the timing of mode switching.

FIG. 6 is a flowchart for explaining the control contents of the improvement device.

FIG. 7 is a flowchart for explaining the control contents of the improvement device.

FIG. 8 is a flowchart for explaining the control contents of the improvement device.

FIG. 9 is a plan view showing a structure of a front axle portion.

FIG. 10 is a plan view of the front axle portion after changing the tread.

FIG. 11 is a cross-sectional view of a main part.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fumio Kuroiwa No. 1 Hachikura, Tobe-cho, Iyo-gun, Ehime Pref.Iseki Agricultural Machinery Co., Ltd. (72) Inventor Naohiko Ishii 1 Yakura, Tobe-cho, Iyo-gun, Ehime Prefecture Iseki Agricultural Machinery Co., Ltd. (72) Inventor Hiroshi Ikekawa 1 Yakura, Tobe-machi, Iyo-gun, Ehime Prefecture Engineering Department (72) Invention Takashi Sekiya No. 1 Yakura, Tobe-cho, Iyo-gun, Ehime Prefecture Izeki Agricultural Machinery Co., Ltd.

Claims (1)

[Claims] 1. In addition to the front wheel steering mode, at least front and rear wheel anti-phase steering modes are provided, and the front wheel steering mode and the front and rear wheels are operated in conjunction with manual mode setting and up / down movement of the working machine. The automatic steering mode is provided with an automatic steering mode in which the steering mode is automatically switched between the wheel antiphase steering modes, and a lifting vehicle for connecting a working machine to the rear of the machine body is used for automatic steering. The height of the work implement lifting link when the vehicle is in the front-rear wheel anti-phase steering mode and the height when returning from the front-rear wheel anti-phase steering mode to the original front wheel steering mode are different. A steering device for a power vehicle, characterized in that