JPS62242207A - Automatic steering mechanism for steering device - Google Patents

Abstract

PURPOSE:To perform sure automatic steering by providing an automatic steering controlling means that supplies high pressure hydraulic oil to one pressure chamber and releases hydraulic oil in another pressure chamber to a tank according to the direction of steering determined by a setting means and a pressure controlling means that restricts supply to the pressure chamber when pressure of the hydraulic oil exceeds a fixed value. CONSTITUTION:Switching of manual steering, right automatic steering and left automatic steering is made by turning a rotary valve 283 to positions of three kinds by a motor 240, and a high pressure operation shaft is led to a power cylinder 120 by narrowing down a discharge tube by a flow rate controlling valve 260 at the time of automatic steering. Pressure in the power cylinder 120 is prevented from becoming too high by a relief valve 270 even when manual steering is made simultaneously, to prevent manual steering from becoming impossible. Switching control of the rotary valve 283, opening control of the flow rate controlling valve 260 and control of relief pressure of the relief valve 270 are performed by a controlling circuit 300 provided with a microcomputer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic steering mechanism of a steering device that causes a vehicle to travel along a predetermined route.

[Conventional technology and problems]

For example, most expressways have small curves, so drivers do not have to make large steering operations while driving, and often continue to drive in this manner for relatively long periods of time. Therefore, driving a vehicle on an expressway tends to be monotonous. Furthermore, while driving on a highway, if a crosswind hits the vehicle, there is a risk that the vehicle will suddenly change course, so drivers must always pay close attention. However, driving on an expressway tends to cause a feeling of fatigue for the driver, and thus a steering device capable of automatic steering has been desired.

On the other hand, power steering devices that reduce the driver's steering force are well known (for example, Japanese Patent Laid-Open No. 59-220
No. 455), if an automatic steering mechanism as described above is added to the power steering device in a vehicle, the device becomes large and complicated.

[Means for solving problems].

The first invention displaces the rod according to the handle operation,
The steering device steers the left and right wheels connected to the rod, and includes a power cylinder in which a piston fixed to the rod is slidably accommodated in a cylinder pore and has two pressure chambers, and a vehicle travel path. a setting means for determining the steering direction of the wheels according to the steering direction; and a setting means for supplying high-pressure hydraulic oil to one pressure chamber and releasing hydraulic oil in the other pressure chamber to a tank according to the predetermined steering direction. The present invention is characterized by comprising an automatic steering control means for controlling the pressure chamber, and a pressure control means for restricting the supply of the hydraulic oil to the pressure chamber when the pressure of the hydraulic oil supplied to the pressure chamber exceeds a certain value.

In addition to the configuration of the first invention, the second invention supplies high pressure hydraulic oil to one pressure chamber and the other pressure chamber in response to the handle operation. power steering control means for releasing hydraulic oil into a tank; cutting means for selectively operating one of the automatic steering control means and the power steering control means; provided between the pressure chamber and the tank;
flow rate control means for changing a flow path area, the flow rate control means relatively increasing the flow path area when the power steering control means is activated, and when the power steering control means is not activated, the flow rate control means relatively increases the flow path area when the power steering control means is not activated. It is characterized by a relatively small flow path area.

〔Example〕

The present invention will be explained below with reference to illustrated embodiments.

FIG. 1 shows a hydraulic circuit according to an embodiment of the present invention, and this embodiment combines a power steering mechanism with an automatic steering mechanism.

First, the configuration of the power steering a structure will be explained.

This mechanism is conventionally known, and hydraulic oil stored in a tank 101 is sucked up by a hydraulic pump 102 and sent under pressure to a control valve 110, passes through this control valve 110, and is returned to the tank 101, and is then operated by a handle (not shown). The power is supplied to the power cylinder 120 via the control valve 110 in accordance with the above. The power cylinder 120 has a piston 122 slidably housed in a cylinder bore 121, which defines first and second pressure chambers 123, 124. Rod 125 fixed to piston 122
extends through the first and second pressure chambers 123 and 124, and is connected to the left and right wheels via a link mechanism (not shown) or the like. Inside the control valve 110, there is a first valve. Second. Third and fourth variable throttles 111, 112, 113, 114 are formed and a torsion bar (not shown) connected to the handle is provided. The variable diaphragm l1l-114 is configured to change the opening degree by the tearing of the torsion bar. .

That is, for example, when the steering wheel is steered to the left, the first and second variable apertures Ill, 11 are opened via the torsion bar.
2 has a small opening, and the third and fourth variable apertures 113.
The opening degree of 114 increases. . As a result, the high-pressure hydraulic oil pumped from the hydraulic pump 102 flows into the first pressure chamber 123 through the third variable throttle 113, while the hydraulic oil in the second pressure chamber 124 flows through the fourth variable throttle 114. and is released into tank 101. Therefore, the first pressure chamber 123
The pressure therein becomes higher than that in the second pressure chamber 124, and the piston 122 is urged toward the second pressure chamber 124, thereby assisting in turning the handle to the left. When steering the steering wheel to the right, the opposite effect takes place and a similar steering assistance is provided. When steering is not performed, the opening degrees of all variable throttles 111 to 114 are the same,
Therefore, the pressures in pressure chambers 123 and 124 are equal, and piston 122 is not biased.

In order to supply the operating shaft to the control valve 110 and the power cylinder 120, the hydraulic pump 102 sucks up hydraulic oil from the tank lot through the suction pipe ti, and pumps it through the discharge pipe I2. The discharge pipe 12 is connected to a first artificial boat 201 of a rotary valve section 200, which will be described later.
01 is connected to the inlet boat 115 of the control valve 110 via the supply pipe 13. The artificial boat 115 has first and third variable apertures 1
11.Communicates with the entrance part of 113. The outlet port [16 of the control valve 110 is the second and fourth variable throttle 112, 114
A second exit robot 2 is connected to the second port 203 of the rotary valve section 200 via the discharge pipe 14, and is provided close to the second port 203.
04 is connected to the tank 101 via a return pipe 15.

On the other hand, an intermediate port 117 provided between the second and third variable throttles 112 and 113 of the control valve 110 is connected to a bow 1-211 of a first switching valve 210, which will be described later, via a control pipe 1'6. , first and fourth variable apertures 111, 11
An intermediate bow H18 provided between the two switching valves 4 and 4 is connected to an f-toe 221 of a second switching valve 220, which will be described later, via a control pipe 17. The other boats 212, 222 of the first and second switching valves 210, 220 are connected to the first and second pressure chambers 1.2 of the power cylinder 120 via communication pipes xa, 1j, respectively.
23.124. First and second switching valve 21
0.220 makes the control jTa pipes 16 and 17 conductive to the communication pipes 18 and 19, respectively, when the power steering mechanism is in operation.

Next, the configuration of the automatic steering mechanism will be explained.

The rotary valve portion 200 is a portion surrounded by a dashed line in FIG. Second and third switching valve 210
, 220, 230, and these switching valves are connected to the motor 24.
Switching is driven by 0. First and second switching valves 210
, 220 are 3-point and 2-position valves, which connect the control pipes 16 and 17 to the communication pipes 18 and 19 in the first position shown, and connect the first and second passages in the second position not shown. 251 and 252 are connected to the communication pipe 18.
19 is made conductive. The third switching valve 230 is a 4-point, 2-position valve, and in the illustrated first position, the third passage 253 that communicates with the first artificial port 201 and the second exit robot 202 is connected to the second passage 252. , and a fourth port connected to the second artificial boat 203 and the second departure port 204.
The passage 254 is connected to the first passage 251. Also, the third
In a second position (not shown), the switching valve 230 connects the third passage 253 to the first passage 251 and connects the fourth iffi passage 254 to the second passage 252.

The flow rate control valve 260 is provided in the middle of the discharge pipe 14, and as described later, relatively increases the flow path area when the power steering mechanism is activated, and increases the flow path area when the power steering mechanism is not activated and automatic steering is performed. Make it relatively small. The flow rate control valve 260 is, for example, a valve driven by a solenoid to change the opening degree of the throttle.

The relief valve 270 is provided in the middle of the relief pipe 21 that connects the discharge pipe 12 and the return pipe 15, and opens when the pressure in the relief pipe 21 exceeds a predetermined value to release high-pressure hydraulic oil in the discharge pipe 12. A portion of the return pipe 15 is intended to be relieved. The relief valve 270 is controlled by, for example, a solenoid to arbitrarily change the relief pressure, and as described later, sets the relief pressure at the maximum during power steering operation and sets the relief pressure at a relatively low level during automatic steering.

2(1) to (dish) and FIG. 4(a) to Cr) show the structure of the rotary valve section 200, and FIG.
, (It) and (t) are respectively shown in Fig. 4 (a
) tz-tz line, n, -n, line and DI 2 I
4 (a) to (f) are cross-sectional views taken along lines 2, A-A, B-B, C-C, and D- in FIG. 2 ([), respectively.
FIG. 3 is a cross-sectional view taken along lines D, E-E, and F-F. In addition, these figures 2 (1) to (l[) and figure 4 (a)
-(f) correspond to the state during power steering operation, that is, the state shown in FIG. In the figure, ■ indicates always high pressure, O indicates always low pressure, and those without these symbols indicate that both pressure states may exist.

The body 280 includes a first artificial port 201, a first exit robot 202, a second artificial boat 203, and a second exit port 2.
04, and baud) 211, 212, 221, 222 are formed. Bore 28 formed in the shaft portion of body 280
1 is fitted with a cylindrical liner 282, and this liner 282
A rotary valve 283 is housed inside so as to be rotatable and slidable around the axis. The rotary valve 283 is integrally fixed to the output shaft 241 of the motor 240 attached to the upper part of the body 280 by any means such as a screw or a key. The motor 240 is controlled by a control circuit 300, which will be described later.
The output shaft 241 and the rotary valve 283 are rotated approximately 60 degrees counterclockwise from the positions shown in FIG. 4(a) to (r) with respect to the liner 282 (positions shown in FIG. It can be rotated by about 60° (positions in FIG. 6(a) to <f)).

The rotary valve 283 has annular outer circumferential grooves 284 and 285.
, 286.

287, and radial holes 288, 289, 290, 2
91 are formed, and the liner 282 has passages 292 to 299 . which can overlap with these annular outer circumferential grooves and radial holes.
277-279 are formed.

The control circuit 300 receives signals from a position sensor 3011 that detects the running position of the vehicle, a pressure sensor 302 that detects the hydraulic pressure acting on the relief valve 270, a vehicle speed sensor 303, a steering angle sensor 304, and a steering force sensor 305.
Based on these signals, the rotary valve section 200, flow rate control valve 260, and relief valve 270 are controlled according to the flowchart of FIG. 12, which will be described later.

The steering device of this embodiment operates in three modes: manual steering (power steering operation), right-turn automatic steering, and left-turn automatic steering, and switching between these modes is performed via the motor 240 as described above. This is done by rotating the rotary valve 283 clockwise or counterclockwise by 60''. Figures 4(a) to (f) show the manual steering mode in which the rotary valve 283 is in the neutral position, and Figure 5(a) shows the manual steering mode. - (f) are right-turn automatic steering modes in which the rotary valve 283 is rotated 60 degrees counterclockwise from the neutral position, and Figures 6 (a) to (f) are modes in which the rotary valve 283 is rotated 60 degrees clockwise from the neutral position. The modes of the rotated left-turn automatic steering are shown. In the figures, thick arrows indicate the flow of high-pressure hydraulic oil, and thin arrows indicate the flow of low-pressure hydraulic oil.

The operation of the rotary valve section 200 will be explained.

In the case of manual steering (power steering operation), the rotary valve 283 operates as shown in Fig. 2 (1) to (I) and Fig. 4 (
It is in the neutral position shown in a) to (f).

In other words, the first artificial boat 201 and the first outgoing robot boat 202
are in communication via the passage 294, the annular outer circumferential groove 285, and the passage 295, and the second artificial boat 203 and the second exit port 2
04 is the passage 277, the annular outer circumferential groove 286 and the passage 279
communicate via. Also, the port 21 of the first switching valve 210
1,212 communicate through the passage 278, the radial hole 290.291, and the passage 292, and the boat 221.222 of the second switching valve 220 communicates with the passage 29G and the radial hole 289.28.
8 and passage 293. On the other hand, although the third switching valve 230 is composed of each passage of the liner 283, there is no flow of hydraulic oil during manual steering. That is, in FIG. 1, the first, second and third switching valves 210, 220
, 230 are in the first position shown, and the flow control valve 260 is fully open.

Therefore, the high pressure hydraulic oil discharged from the hydraulic pump 102 is transferred from the 1st input robot 1-201 to the 1st output robot 2
02 to the control valve 110, and this control valve 110
It flows out from the tank 101 through the flow control valve 260 and from the second artificial boat 203 through the second outlet port 204.
Reflux to. If you turn the steering wheel to the right at this point,
Third and fourth variable throttles 113, 114 of control valve 110
is throttled and the first and second variable throttles 111, 112 are opened, so that high-pressure hydraulic oil flows as shown in FIGS. 4(a) and 4(b).
) and (c), and low-pressure hydraulic oil flows as shown in the thin arrows shown in FIGS. 4(d), (e), and (f). That is, as indicated by the broken line arrow shown in FIG. room 12
3, the low pressure hydraulic oil is supplied to the first switching valve 210 and the second variable throttle 1.
12 and flow rate control valve 260 to the tank 101. As a result, the pressure in the second pressure chamber 124 increases, and the piston 122 is urged to the left in FIG. 7, thereby assisting the steering wheel operating force. In the case of steering the steering wheel to the left, the operation is opposite to the above.

In the case of right-turn automatic steering, the rotary valve 283 is
) to (I) and FIGS. 5(a) to (f), the position is rotated 60' counterclockwise from the neutral position. In other words, the first large robot 201 and the first robot 1-
202 is a passage 294, an annular outer circumferential groove 285 and a passage 29
5, and the second artificial port 203 and the second exit robot 204 communicate via a passage 277, an annular outer circumferential groove 286, and a passage 279.

This communication state is the same as during manual steering, but
During automatic steering, the flow path area of the discharge pipe 14 (Fig. 1) is narrowed by the flow control valve 260 (Fig. 1), so that the hydraulic oil does not substantially flow through the control valve 110 (Fig. 1). It has become.

Further, the first entry port 201 is connected to the second switching valve 2 through the passage 294, the annular outer circumferential groove 285, the passage 298, the radial hole 289, the annular outer circumferential groove 284, and the passage 293.
The boat 212 of the first switching valve 210 communicates with the second outlet port 204 via the passage 292, the annular circumferential groove 287, the radial holes 291, 290, and the passage 279. That is, in FIG. 1, the first and second switching valves 210 and 220 are in a second position different from that shown. Therefore, as indicated by the broken line arrow shown in FIG.
The second power cylinder 120 is connected to the power cylinder 120 through the communication pipe 19.
The low-pressure hydraulic oil in the first pressure chamber 123 is guided to the pressure chamber 124 and flows through the communication pipe 18 and the first and fourth passages 251, 25.
4 and return pipe 15 to tank 101.

As a result, the pressure in the second pressure chamber 124 increases, and the piston 1
22 is biased to the left in FIG. 8, and the steering wheel is steered to the right.

As described above, in the automatic steering mode, the flow rate control valve 260 is opened to a small degree, so that most of the hydraulic fluid flows within the rotary valve section as indicated by the dashed arrow in FIG. hardly flows through control valve 110. The amount of hydraulic oil flowing through the control valve 110 is the flow rate wi control valve 260.
The smaller the opening degree, the smaller the amount. Therefore the first and second pressure chambers 123, 124 in autopilot mode
The pressure difference, that is, the force that displaces the piston 122 becomes larger as the opening degree of the flow control valve 260 becomes smaller.

In the case of left-hand automatic steering, contrary to right-hand automatic steering, the rotary valve 283 is located at a position rotated 60'' clockwise from the neutral position, as shown in FIGS. 6(a) to (r). As shown in FIG. 9, the first, second and third switching valves 21
0.220 is in the second position, therefore hydraulic pump 1
The high pressure hydraulic oil discharged from 02 is the power cylinder 120
The low pressure hydraulic fluid in the second pressure chamber 124 is supplied to the first pressure chamber 123 of the tank 101 . As a result, the pressure in the first pressure chamber 123 becomes higher than that in the second pressure chamber 124, the piston 122 is urged to the right in FIG. 9, and the handle is steered to the left.

In this way, in the case of automatic steering, high-pressure hydraulic oil is introduced into the first or second pressure chamber 123, 124 of the power cylinder 120 to energize the piston 122, and thereby the driver does not have to operate the steering wheel. Right or left steering is automatically performed. Here, consider a case where the driver simultaneously performs manual steering during automatic steering.

FIG. 10 shows a case where the driver performs left-turn steering while performing right-turn automatic steering. High-pressure hydraulic oil is force-fed into the second pressure chamber 124 of the power cylinder 120 by the right-hand automatic steering, and the piston 122 is urged in the direction of the thin arrow P, and at the same time, the piston 122 is urged by the driver's left-turn steering. is biased in the direction of thick arrow Q.

Assuming that the relief valve 270 is not provided, the pressure in the second pressure chamber 124 will rapidly increase because high-pressure hydraulic oil continues to be supplied to the second pressure chamber 124 due to the right-turn automatic steering. Not only is it impossible to turn the steering wheel to the left, but the steering wheel also turns sharply to the right, which is dangerous for the driver. This becomes more noticeable the more you try to steer in the opposite direction to the automatic steering direction. However, in this embodiment, the discharge pipe 12 and the return pipe 15 are connected to the relief pipe 2.
1, and a relief valve 270 is provided in this relief pipe 21.
The relief pipe 2 is opened when the pressure on the upstream side of 0 becomes equal to or higher than a set value. In the case of right-turn automatic steering, the upstream side of the relief valve 270 of the relief pipe 21 communicates with the second pressure chamber 124 via the third and second passages 253 and 252, the control pipe 17, and the communication pipe 18, That is, the pressure is the same as that of the second pressure chamber 124. Therefore, when the pressure inside the second pressure chamber 124 exceeds a set value, the relief valve 270 opens the relief pipe 21 to limit the amount of high-pressure hydraulic oil supplied to the second pressure chamber 124. The pressure within the second pressure chamber 124 is suppressed to a set value or less.

This allows the driver to perform left-turn steering, although this requires a relatively large steering force.

FIG. 11 shows a case where the driver performs abort steering while performing right-turn automatic steering. As in the case of FIG. 10, the piston 122 of the power cylinder 120 is biased in the direction of the thin arrow P due to the right-hand automatic steering, and the piston 122 is biased in the direction of the thick arrow Q due to the driver's right-hand steering.
trying to move in the direction of That is, the driver's steering force on the steering wheel is assisted by the pressure of the high-pressure hydraulic oil, and the driver can perform right-turn steering with a small steering force.

As described above, in this embodiment, the rotary valve 283 is rotated to three different positions by the motor 240, thereby switching between manual steering, right-turn automatic steering, and left-turn automatic steering, and during automatic steering, the flow rate is controlled. The discharge pipe 14 is throttled by the valve 260 and the high pressure operating shaft is connected to the power cylinder 120.
Furthermore, even if manual steering is performed at the same time as automatic steering, the relief valve 270 prevents the pressure inside the power cylinder 120 from becoming too high and prevents manual steering from becoming impossible. Such switching control of the rotary valve 283, flow rate control valve 26
Control of the opening degree of 0 and control of the relief pressure of the relief valve 270 are performed by a control circuit 300 constructed by a microcomputer 9'c.

FIG. 12 shows a flowchart of a control program by the control circuit 300. This control program may be started at the same time as the vehicle starts traveling, or may be started by the driver turning on a manual switch (not shown). Furthermore, when this control program is started, the rotary valve 283 may be in a neutral position, that is, in a manual steering state, or in a right-turning or left-turning automatic steering state.

This control program is interrupted every 200 m5ec, for example. In step 401, the set distance is read. The set distance MD is the target value of the distance between the guide and the vehicle, which is the reference for the travel route. For example, when the vehicle 21 is run along the guide 22 located on the side of the vehicle 21 as shown in FIG. 13, the set distance ND0 is the distance between the axle and the guide 22, and as shown in FIG. When the vehicle 2I is run along the line 23 on the road surface, the set distance D0 is the distance M between the axle and the line 23 (for example, Do-〇 may be used).This set distance D0 is determined in advance by a program. Alternatively, the driver may manually set the setting when starting the control program.

In step 402, the current speed of the vehicle and the distance from the guide are read. The vehicle speed V is determined by the vehicle speed sensor 303.
Further, the distance #D is detected by the position sensor 301, respectively. Next, in step 403, the set throttle amount Q0 of the flow control valve 260 and the relief valve 2 are adjusted based on the current vehicle speed V.
Set relief pressure S of 70. , and the set steering angle θ. Calculate. As the vehicle speed V increases, it is safer to increase the steering force and decrease the steering speed. Therefore, the set aperture amount Q. , set relief pressure S0, and set steering angle θ. is determined to become smaller as the vehicle speed V increases.

When the difference between the current distance #D of the vehicle from the guide and the set distance Dt (CD-D) is O, that is, when the vehicle is traveling along a predetermined route, it is necessary to perform automatic steering. , the program runs from step 404 to step 41
2, after switching to the manual steering state, in step 413, the flow rate control valve 260 is turned off, that is, fully opened, and the process ends.

On the other hand, when the difference (DD,) is not O, that is, when the vehicle deviates from the predetermined travel route, the process moves from step 404 to step 405.

Step 405 turns on the flow rate control valve 260.

That is, the flow control valve 260 is throttled to the set throttle tQO determined in step 403. In step 406, the distance FID of the current vehicle from the guide is set as the distance D0.
It is determined whether the difference (DD,) is a positive value or a negative value. If the difference (DD,) takes a negative value, the vehicle is traveling on the left side of the determined travel route, so the process moves to step 407 and performs right-turn automatic steering. That is, rotary valve 2
83 is switched to the states shown in FIGS. 5(a) to <r>. Conversely, if the difference (DD,) takes a positive value, the vehicle is traveling on the right side of the determined travel route, so step 40
Move to 8 and perform left turn steering. That is, the rotary valve 283 is switched to the states shown in FIGS. 6(a) to 6(f).

Next, in step 409, the pressure S acting on the relief valve 270 detected by the pressure sensor 302 and the current steering angle θ detected by the steering angle sensor 304 are read. In step 410, it is determined whether the difference (S-3o) between the pressure S and the set relief pressure S0 is 0 or more. Difference (S
So) takes a negative value, that is, the relief valve 270
If the pressure S acting on is smaller than the set relief pressure S0, it is possible for the driver to perform manual steering during this automatic steering, and the automatic steering is continued and step 411
Proceed to.

On the other hand, if the difference (S So) takes a value of 0 or more, that is, if the pressure S acting on the relief valve 270 is the set relief pressure 30 or more, the process moves to step '412, switches to the manual steering state, and The flow control valve 260 is set to OPP, that is, fully opened. As explained with reference to FIG. 10, when the direction of automatic steering and the direction of manual steering are opposite, the pressure acting on the relief valve 270 increases and the relief valve 270 opens, and the pressure in the power cylinder 120 increases. The control program is configured to prevent the pressure from increasing in the chambers 123 and 124, but at the same time the control program switches to a state of manual steering to increase safety.

On the other hand, when the process proceeds from step 410 to step 411, the current steering angle θ and the set steering angle θ are determined. The difference between (θ−θ.)
Determine whether or not is 0. If this difference (θ-00) is not 0, the current steering angle θ is still the set steering angle θ. Since the current state of the rotary valve 283 is maintained and further steering is performed, this program is ended by skipping steps 412 and 413. On the other hand, the difference (θ−θ.)
is 0, the current steering angle θ is the set steering angle θ.

has been reached, so execute step old 2 to switch to manual steering and end automatic steering, and then step 413.
At this time, the flow control valve 260 is turned off, that is, fully opened.

For example, when right turn automatic steering is performed,
The control program is interrupted every 200m5ec and steps 401, 402, 403, 404, 405
．． 406.407°, 409.410.411, and the steering angle θ gradually increases to the set steering angle θ. As I approached,
During this time, when the distance of the vehicle from the guide reaches the set path MD0, the process moves from step 404 to steps 412 and 413, and the state is switched to the manual steering state. Also, the steering angle θ becomes the set steering angle θ before the distance reaches the set distance. , the control program executes steps 412 and 413 after step 411 to switch to manual steering, and the steering angle θ is the set steering angle θ. control so as not to exceed.

That is, in automatic steering mode, the distance from the vehicle guide, fiID, is always the set distance. Right-turn or left-turn automatic steering is performed so that the steering error 〇 is the set steering angle θ. It is designed not to exceed. On the other hand, when the driver performs manual steering during automatic steering and the pressure S acting on the relief valve 270 becomes equal to or higher than the set relief pressure 30, steps 410 to 412.41
Move to 3 and switch to manual steering state.

Set steering angle θ. is determined according to the vehicle speed V to prevent the vehicle from spinning. Further, the steering speed in the automatic steering mode is determined by the set throttle iQ of the flow rate control valve 260. is controlled according to the vehicle speed V, thereby preventing sudden steering.

Furthermore, a relief valve 270 is provided, and when the pressure S of the relief valve 270 becomes equal to or higher than the set relief pressure 30 due to manual steering by the driver in the automatic steering mode, the relief valve 270 is opened and the steering force becomes abnormally large. It is possible to switch to a manual steering mode that prevents this from happening and also provides the effect of so-called power steering. Note that when the driver steers in the same direction as the automatic steering, the pressure S does not increase, so the relief valve 270 does not operate, and the steering force is assisted by the automatic steering.

FIG. 15 shows another embodiment of the control program.

In this embodiment, in addition to the control shown in FIG. 12, control is performed in consideration of the influence of crosswinds. That is, a crosswind sensor that detects a crosswind is attached to the vehicle, and when the vehicle is subjected to a disturbance such as a crosswind or a gust of wind, the direction of travel is prevented from changing due to this disturbance.

The control program shown in FIG. 15 is roughly the same as the control program shown in FIG. 12, and differs only in the portion related to crosswinds. That is, steps 501, 505, 507°508.5
09, 512, and 513 are steps 401 and 4, respectively.
05°407, 408. It performs exactly the same processing as '409.412.413.

In step 502, the current vehicle speed ■, the distance from the guide, and the wind speed V of the crosswind are read. In step 503, based on the vehicle speed V and the wind speed V, the vehicle displacement due to crosswind DI,
Set throttle amount Q1 of flow control valve 260, relief valve 270
The set relief pressure S7 and the set steering angle θ1 are calculated. - In step 504, the deviation Dl of the vehicle due to the crosswind and the set distance are determined from the current distance of the vehicle from the guide. It is determined whether the difference obtained by subtracting (D'-D I DO) is O. Here, the set distance D0 is the distance between the guide and the vehicle's target travel route, and takes a value that is positive when the target travel route is on the right side of the guide, and distance #D is the value that is positive when the vehicle is on the right side of the guide. It is assumed that the deviation Dl takes a positive value when the vehicle is located on the right side of the target travel route. Step 5
When it is determined that the difference (D-D, -Do) is 0 in step 04, the vehicle is traveling on a predetermined route including the influence of crosswinds, there is no need for automatic steering, and the process moves to step 512. At the same time as switching to manual steering state, step 5
At step 13, the flow rate control valve 260 is turned off to end the program. On the other hand, the difference (D DI Do)
is not 0, steps 505 and subsequent steps are executed to perform automatic steering.

In step 505, the flow control valve 260 is turned on to throttle the flow to the set throttle amount Q. In step 506, the difference (D
It is determined whether DI Do) is a positive value or a negative value, and if it is a negative value, right turn automatic steering is performed in step 507, and if it is a positive value, left turn automatic steering is performed in step 508.

In step 509, the pressure S acting on the relief valve 270 and the steering angle θ are read. In step 510, the pressure S
It is determined whether the difference (S-3,) between and the set relief pressure SI is 0 or more, and if this difference (S-51) takes a negative value,
Continuing the automatic steering state, the process moves to step 511, where the difference (S
-Sl) takes a value greater than or equal to 0, step 512.
513 is executed to switch to the manual steering state and to set the flow rate control valve 260 to the op state.

When proceeding from step 51O to step 511, it is determined whether the difference (θ-01) between the current steering angle θ and the set steering angle θ is 0, and if this difference (θ-01) is not 0, Step 512.51 to maintain the current autopilot state.
Skip step 3 and exit this program. On the other hand,
If the difference (θ−θI) is O, step 512
．． 513 is executed to switch to the manual steering state and turn off the flow rate control valve 260.

As described above, according to the control program shown in Fig. 15, the influence of crosswinds is taken into consideration, and when a crosswind is detected, the positional deviation of the vehicle due to the crosswind is calculated in advance, and the system is automatically set to prevent this deviation Dl from occurring. Steering is performed. In addition, the flow rate control valve 26
The set throttle amount Q1 of 0, the set relief pressure S1, and the set steering angle θ1 are also determined in consideration of the influence of crosswinds. As a result, smoother steering becomes possible and driving stability is improved.

16 to 18 show other embodiments of the drive source for the rotary valve section 200. That is, although the rotary valve portion 200 was driven by the motor 240 in the above embodiment, it is driven by a gear type hydraulic motor 600 using a piezo actuator 601 in this embodiment. The drive shaft 602 and the driven shaft 603 are housed in a body 604, are arranged parallel to each other, and are each supported rotatably around their respective axes.

The drive shaft 602 protrudes into the body 280 of the rotary valve section 200, and a rotary valve 283 is fixed to the protruding end thereof.

The driven shaft 603 projects outward from the body 604, and its projecting end is connected to a rotary encoder 605 attached to the outer surface of the body 604. A drive tooth 60G provided on the drive shaft 602 and a driven gear 6 provided on the driven wheel 603
07 and meshes with each other. These gears 606.607
The engaging portion is an oil passage 60B formed in the body 604.
Come within. Therefore, when the hydraulic oil flows in this oil passage 608, the driving gear 606 and the driven gear 607, that is, the driving shaft 602 and the driven shaft 603, rotate around their axes, thereby rotating the rotary valve 283 and the rotary encoder 605.

The piezo actuator 601 is formed by laminating a large number of plate-shaped piezo elements, and is provided in a bore 612 in an actuator body 611 provided adjacent to the body 604. The piezo actuator 601 is fixed in a bore 612 at its upper end in FIG. 17, and has a piston 6 at its lower end.
13 is installed. A pump 614 formed by the piston 613 and the bore 612 is provided with a disc spring 615, and the disc spring 615 biases the piston 613 in the direction of contacting the piezo actuator 601. The piezo actuator 601 is connected to the control circuit 3 via a lead wire 616.
00 (Fig. 1), and this control circuit 300
It expands and contracts when power is supplied or cut off. In addition,
A low-resolution encoder 605 is also connected to the control circuit 300.

A plunger 622 is slidably accommodated in a valve hole 621 communicating with the =1 minp chamber 614 . Valve hole 62
1 is an inlet bow 1 leading to a hydraulic pump 102 (FIG. 1).
-623 and the oil passage 608 can also communicate with each other. The plunger 622 has an annular groove 624 on its outer circumferential surface and a conical seat portion 625 at its end. The annular groove 624 is
The seat portion 625 faces the throttle passage 626 communicating with the pump chamber 614 and the inlet boat 623, and can be brought into close contact with a conical seat surface 627 formed at the end of the valve hole 621.

The plunger 622 is constantly biased by the spring 628 in the direction in which the seat portion 625 comes into close contact with the seat surface 627.
When not in operation, the seat portion 625 is in close contact with the seat surface 627,
As a result, the oil passage 608 is cut off from the inlet boat 623.

When the piezo actuator 601 is energized and expanded, the pump chamber 614 contracts, and as shown in FIG. 18, the hydraulic oil in the pump chamber 614 displaces the plunger 622 in the direction of arrow R against the spring 628. . As a result, the seat portion 625 is separated from the seam surface 627, and the annular groove 624 comes to face the seat surface 627. Therefore, the hydraulic oil flowing in from the inlet port 623 passes through the annular groove 624, passes between the seat portion 625 and the seat surface 627, flows into the oil passage 60B, and passes through the meshing portion of the gears 606 and 607 to the output port. 29 to the outside. As a result, the gears 606 and 607, that is, the drive shaft 6
02 and the driven shaft 603 rotate, and the rotary valve 283 rotates. In addition, a rotary encoder 60
5 also rotates, and the signal remaining by this rotation angle is sent to the control circuit 30.
It is input to 0.

While detecting this signal, the control circuit 300 energizes the piezo actuator 601 to rotate the rotary valve 283 by a predetermined angle.

In this way, in this embodiment, the hydraulic oil is supplied to the oil passage 608.
Since the fluid flows in one direction, the drive shaft 602 and rotary valve 283 rotate only in one direction to switch between manual steering and automatic steering.

The configuration of the rotary valve section 200 is shown in FIGS.
The configuration is exactly the same as I).

In each of the above embodiments, an automatic steering mechanism is added to a power steering device, but the power steering device is not essential, and an automatic steering mechanism may be added to a normal steering device.

〔Effect of the invention〕

As described above, according to the present invention, with a simple and compact structure,
A steering device that can perform reliable automatic steering can be obtained.

[Brief explanation of drawings]

Figure 1 is a hydraulic circuit diagram showing one embodiment of the present invention, and Figure 2 (
IJ, (It), (1) is a sectional view showing the rotary valve part in the manual steering state, and Fig. 2<r)
is a sectional view taken along the line 12-12 in Fig. 4(a), and Fig. 2(
11) is a sectional view taken along the line ■2-■2 of Fig. 4 (a), Fig. 2 (IL) is a sectional view taken along the mz mz line of Fig. 4 (3), Fig. 3 (1), (Wataru) and (III) are cross-sectional views showing the rotary valve part in the right-turning automatic steering state, and Fig. 3 (I)
is a cross-sectional view along line 13 Is in Figure 5(a),
Figure (1) is a cross-sectional view taken along the ■i 113 line in Figure 5 (a), and Figure 3 (I) is a cross-sectional view taken along line III z Il in Figure 5 (a).
l A sectional view taken along line 3, Figures 4 <a> to ``) are sectional views showing the rotary valve and cylindrical liner in the manual steering state, and Figure 4 (a) is a sectional view taken along line A- in Figure 2 (1). 4(b) is a sectional view taken along line A, FIG. 4(b) is a sectional view taken along line B-B of FIG. 2(1), and FIG. 4(c) is a sectional view taken along line C and -C of FIG. 2(1). 4(d) is a sectional view taken along line D-D in FIG. 2(f), and FIG. 4(e) is a sectional view taken along line E-E in FIG. Figure 4(f) is a sectional view taken along the line FF in Figure 2(1), and Figure 5<a) to (
f) is a cross-sectional view showing the rotary valve and the cylindrical liner in the right-turning automatic steering state, and Fig. 5(a) is a cross-sectional view showing A- in Fig. 3(f).
A cross-sectional view along line A, FIG. 5(b) is B- in FIG. 3(1).
A cross-sectional view along line B, Figure 5 (C) is C in Figure 3 (1).
- A cross-sectional view along line C, Figure 5 (d) is D of Figure 3 (1).
- A cross-sectional view along line D, Fig. 5(e) is E of Fig. 3(1).
- Cross section along line E, Fig. 5 ('') is F- of Fig. 3 (1)
6(a) to 6(f) are sectional views showing the rotary valve and the cylindrical liner in the left-turning automatic steering state;
is a cross-sectional view at the same height position as FIG. 5(a), FIG. 6(b) is a cross-sectional view at the same height position as FIG. 5(b),
Fig. 6(C) is a sectional view at the same height as Fig. 5(C), Fig. 6(d) is a sectional view at the same height as Fig. 5(6), Fig. 6(e) is a sectional view at the same height position as Fig. 5(e), Fig. 6(f) is a sectional view at the same height position as Fig. 5(f), and Fig. 7 is a hydraulic circuit diagram showing the manual steering state. , Fig. 8 is a hydraulic circuit diagram showing a right-hand automatic steering state, Fig. 9 is a hydraulic circuit diagram showing a left-hand automatic steering state, and Fig. 10 shows a state in which left-hand manual steering is performed in a right-hand automatic steering state. 11 is a hydraulic circuit diagram showing a state in which right-turn manual steering is performed in a right-turn automatic steering state. FIG. 12 is a flowchart showing an example of a control program. FIG. 14 is a schematic diagram showing the case where the vehicle runs along a line on the road surface. FIG. 15 is a flowchart showing another example of the control program. FIG. 17 is a horizontal sectional view showing the hydraulic motor; FIG. 18 is a horizontal sectional view showing the operating state of the hydraulic motor. 101...Tank, 102...Pump,
120...Power cylinder, 121...Cylinder pore, 122...Piston, 123.124...
・Pressure chamber, 125...Rod, 200...
・Rotary valve part, 210, 220.230... 1st.
Second and third switching valves, 240... motor,
260...Flow rate control valve, 270...Relief valve (pressure control means), 283...Rotary valve (automatic steering control means), 300...Control circuit.

Claims (1)

[Claims] 1. A steering device that displaces a rod in response to a steering wheel operation and steers left and right wheels connected to the rod, in which a piston fixed to the rod can freely slide into a cylinder bore. a power cylinder housed in a power cylinder and having two pressure chambers, a setting means for determining the steering direction of the wheels according to the traveling route of the vehicle, and high-pressure hydraulic oil being supplied to one pressure chamber according to the steering direction determined by the setting means. and an automatic steering control means for supplying hydraulic oil in the other pressure chamber and releasing the hydraulic oil in the other pressure chamber to the tank, and supplying the hydraulic oil to the pressure chamber when the pressure of the hydraulic oil supplied to the pressure chamber exceeds a certain value. An automatic steering mechanism for a steering device, comprising a pressure control means for limiting the pressure. 2. A steering device that displaces a rod in response to a steering wheel operation to steer the left and right wheels connected to the rod, in which a piston fixed to the rod is slidably accommodated in a cylinder bore, and two A power cylinder having a pressure chamber, a setting means for determining the steering direction of the wheels according to the traveling route of the vehicle, and supplying high pressure hydraulic oil to one pressure chamber and supplying high pressure hydraulic oil to the other pressure chamber according to the steering direction determined by the setting means. automatic steering control means for releasing hydraulic oil in a pressure chamber to a tank; and supplying high-pressure hydraulic oil to one pressure chamber of the power cylinder and releasing hydraulic oil in the other pressure chamber to a tank in response to a handle operation. a power steering control means, a switching means for selectively operating one of the automatic steering control means and the power steering control means, a flow rate control means provided between the pressure chamber and the tank and changing a flow path area; pressure control means for restricting the supply of hydraulic oil to the pressure chamber when the pressure of the hydraulic oil supplied to the pressure chamber exceeds a certain value, and the flow rate control means controls the power steering control means. An automatic steering mechanism for a steering device, characterized in that when the power steering control means is in operation, the flow passage area is made relatively large, and when the power steering control means is not in operation, the flow passage area is made relatively small.