JPH085395B2 - Automatic steering mechanism of steering device - Google Patents

Description

Description: TECHNICAL FIELD 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 of highways have a small degree of curve, so that the driver does not need to operate a large steering wheel while traveling, and such a driving state is often continued for a relatively long time. Therefore, driving a vehicle on an expressway tends to be monotonous. In addition, when a cross wind is received while traveling on an expressway, the vehicle may suddenly change its course, and the driver must always pay close attention. However, driving on an expressway tends to cause a driver to feel tired, and conventionally, a steering device capable of automatic steering has been desired.

On the other hand, a power steering device that reduces the steering wheel operating force of the driver is well known (for example, Japanese Patent Laid-Open No. 59-220455).
However, if the automatic steering mechanism as described above is simply added to this power steering device, the device becomes large and complicated [Means for Solving the Problems] A steering device for displacing a rod in accordance with the above, and steering left and right wheels connected to the rod, wherein a piston fixed to the rod is slidably accommodated in a cylinder bore and has two pressure chambers. According to the power cylinder, setting means for setting the distance between the guide and the vehicle installed in the running direction on the running route, and the steering direction set by this setting means,
Automatic steering control means for supplying high pressure hydraulic oil to one pressure chamber and releasing the hydraulic oil in the other pressure chamber to the tank, and when the pressure of the hydraulic oil supplied to the pressure chamber exceeds a certain value. Pressure control means for limiting the supply of hydraulic oil to the pressure chamber is provided.

A second aspect of the invention is, in addition to the configuration of the first aspect of the invention, a power steering control means for supplying high pressure hydraulic fluid to one pressure chamber and releasing the hydraulic fluid in the other pressure chamber to a tank in response to a steering wheel operation. A switching means for selectively activating 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 for changing the flow passage area, and a manual operation during automatic steering. It is characterized by further comprising pressure control means for restricting the supply of hydraulic oil to the pressure chamber so that the pressure of the hydraulic oil in the pressure chamber does not exceed a certain value when steering is performed simultaneously.

In a third aspect of the invention, in addition to the configuration of the second aspect of the invention, the flow rate control means makes the flow passage area relatively large when the power steering control means is operating, and when the power steering control means is not operating. The channel area is relatively small.

〔Example〕

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

FIG. 1 shows a hydraulic circuit according to an embodiment of the present invention, which is a combination of a power steering mechanism and an automatic steering mechanism.

First, the configuration of the power steering mechanism will be described. This mechanism is conventionally known, and the hydraulic oil stored in the tank 101 is sucked up by the hydraulic pump 102 and pressure-fed to the control valve 110, passes through the control valve 110 and is returned to the tank 101, and a handle (not shown) is operated. Is supplied to the power cylinder 120 via the control valve 110. Power cylinder 120
Piston 122 slidably housed in cylinder bore 121
With the piston 122, the first and second pressure chambers 1
23,124 are formed. Rod 1 fixed to piston 122
25 extends through the first and second pressure chambers 123, 124 of FIG.
It is connected to the left and right wheels via a link mechanism (not shown). First, second, third and fourth variable throttles 111, 112, 113, 114 are formed in the control valve 110, and a torsion bar (not shown) connected to the handle is provided. The variable throttles 111 to 114 are adapted to change the opening degree by twisting the torsion bar.

That is, for example, when the steering wheel is steered to the left, the opening degrees of the first and second variable throttles 111 and 112 are small and the opening degrees of the third and fourth variable throttles 113 and 114 are large via the torsion bar. . 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. It is released to the tank 101 through. Therefore, the pressure in the first pressure chamber 123 becomes higher than that in the second pressure chamber 124, and the piston 122 is biased toward the second pressure chamber 124 side,
This assists the steering wheel left-turning operation. When the steering wheel is steered to the right, the opposite effect occurs,
Similar steering wheel operation assistance is provided. When the steering is not performed, the opening degrees of all the variable throttles 111 to 114 are the same, so that the pressures of the pressure chambers 123 and 124 are equal and the piston 122 is not biased.

In order to supply the operation shaft to the control valve 110 and the power cylinder 120, the hydraulic pump 102 sucks up the working oil in the tank 101 through the suction pipe 11 and pumps it through the discharge pipe 12. Discharge pipe 12
Is connected to a first inlet port 201 of a rotary valve unit 200 described later, and a first outlet port 202 provided near the first inlet port 201 is an inlet port 115 of the control valve 110 via the supply pipe 13. Connected to. The inlet port 115 communicates with the inlet portions of the first and third variable throttles 111 and 113. The outlet port 116 of the control valve 110 communicates with the outlet portions of the second and fourth variable throttles 112 and 114, is connected to the second inlet port 203 of the rotary valve portion 200 via the discharge pipe 14, and is connected to the second inlet port 203. The second outlet port 204 provided in close proximity is connected to the tank 101 via the return pipe 15. On the other hand, the intermediate port 1 provided between the second and third variable throttles 112, 113 of the control valve 110
17 is connected via a control pipe 16 to a port 211 of a first switching valve 210 described later, and an intermediate port 118 provided between the first and fourth variable throttles 111 and 114 is a second switching valve 220 described later.
Is connected to the port 221 via the control pipe 17. The other ports 212, 222 of the first and second switching valves 210, 220 are connected to the first and second pressure chambers 123, 124 of the power cylinder 120 via the communication pipes 18, 19, respectively. First and second switching valve 2
When the power steering mechanism operates, the reference numerals 10,220 make the control pipes 16,17 and the communication pipes 18,19 electrically conductive.

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

The rotary valve portion 200 is a portion surrounded by a one-dot chain line in FIG. 1, and includes the first, second and third switching valves 210, 220,
230, and these switching valves are switching-driven by a motor 240. The first and second switching valves 210 and 220 are both 3-port, 2-position valves, and respectively connect the control pipes 16 and 17 to the communication pipes 18 and 19 at the illustrated first position and the first at the second position (not illustrated). And the second passage 251,252 to the communication pipe 1
Conduct to 8,19. The third switching valve 230 is a 4-port 2-position valve, and in the illustrated first position, the first inlet port
The third passage 253 communicating with the 201 and the second outlet port 202 is connected to the second passage 252, and the fourth passage 254 communicating with the second inlet port 203 and the second outlet port 204 is connected to the first passage 25.
Conduct to 1. The third switching valve 230 connects the third passage 253 to the first passage 251 and the fourth passage 254 to the second passage 252 at a second position (not shown).

The flow rate control valve 250 is provided in the middle of the discharge pipe 14, and as will be described later, the flow passage area when the power steering mechanism is in operation is relatively large and the flow passage area when the power steering mechanism is not in operation and automatic steering is performed. Make it relatively small. The flow rate control valve 260 is a valve that is driven by, for example, a solenoid to change the opening 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 is opened when the pressure in the relief pipe 21 becomes equal to or higher than a predetermined value. A part is relieved to the return pipe 15. The relief valve 270 is controlled by, for example, a solenoid to arbitrarily change the relief pressure, and as will be described later, the relief pressure during power steering operation is set to the maximum and the relief pressure during automatic steering is set to be relatively low.

2 (I) to (III) and 4 (a) to (f).
Shows the structure of the rotary valve unit 200, and is shown in FIGS.
I), I ₂ -I _2-wire (III) Figure 4, each (a), II ₂
-II ₂ line and III _2- III ₂ line sectional drawing, FIG. 4 (a)-(f) are AA line of FIG. 2 (I), and B, respectively.
It is sectional drawing which follows the -B line, the CC line, the DD line, the EE line, and the FF line. Further, these FIG. 2 (I) to (II
I) and FIGS. 4A to 4F correspond to the state when the power steering is operating, that is, the state shown in FIG.
In the figure, indicates always high pressure, and always low pressure, and those without these signs indicate that both pressure states can exist.

The body 280 has a first inlet port 201 and a first outlet port
202, a second inlet port 203, a second outlet port 204, and ports 211,212,221,222 are formed. A tubular liner 282 is fitted in a bore 281 formed in the shaft portion of the body 280, and a rotary valve 283 is housed in the liner 282 so as to be rotatable and slidable around its axis. The rotary valve 283 is integrally fixed to the output shaft 241 of the motor 240 mounted on the upper portion of the body 280 by any means such as a screw or a key. motor
The output shaft 241 is controlled by the control circuit 300 described later.
And the rotary valve 283 with respect to the liner 282 about 60 ° counterclockwise from the positions of FIGS. 4 (a) to (f) (positions of FIGS. 5 (a) to (f)) or about clockwise. It can be rotationally displaced by 60 ° (positions in FIGS. 6 (a) to (f)).

The rotary valve 283 has annular outer peripheral grooves 284, 285, 286, 287,
Radial holes 288,289,290,291 are formed, and liner 282 is formed with passages 292-299, 277-279 that are superimposable in these annular peripheral grooves and radial holes.

The control circuit 300 receives signals from the position sensor 301 that detects the traveling position of the vehicle, the pressure sensor 302 that detects the hydraulic pressure acting on the relief valve 270, the vehicle speed sensor 303, the steering angle sensor 304, and the steering force sensor 305. Based on these signals, the rotary valve section will follow the flow chart of Fig. 12 to be described later.
200, flow control valve 250 and relief valve 270 are controlled.

The steering system of the present embodiment operates in three types of modes: manual steering (power steering operation), right-turn automatic steering, and left-turn automatic steering. Switching between these modes is performed via the motor 240 as described above. It is performed by displacing the rotary valve 283 by 60 ° clockwise or counterclockwise. 4 (a) to 4 (f) are manual steering modes in which the rotary valve 283 is in the neutral position, and in FIGS. 5 (a) to 5 (f), the rotary valve 283 is rotated 60 ° counterclockwise from the neutral position. Right-turn automatic steering mode, 6th
Figures (a) to (f) respectively show left-turn automatic steering modes in which the rotary valve 283 is rotated by 60 ° clockwise from the neutral position. In the figure, 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 described.

In case of manual steering (power steering operation),
The rotary valve 283 is in the neutral position shown in FIGS. 2 (I) to (III) and FIGS. 4 (a) to (f). That is, the first inlet port 201 and the first outlet port 202 communicate with each other through the passage 294, the annular outer peripheral groove 285 and the passage 295, and the second inlet port 20
3 and the second outlet port 204 communicate with each other through the passage 2777, the annular outer peripheral groove 286 and the passage 279. The ports 211 and 212 of the first switching valve 210 communicate with each other through the passage 278, the radial holes 290 and 291, and the passage 292, and the ports 221 and 222 of the second switching valve 220 communicate with the passage 29.
6, communicating through radial holes 289,288 and passage 293.
On the other hand, the third switching valve 230 is composed of each passage of the liner 283, but there is no flow of hydraulic oil during manual steering. That is, in FIG. 1, the first, second and third switching valves 210, 22
0,230 is in the first position shown and the flow control valve 260
Is fully open.

Therefore, the high-pressure hydraulic fluid discharged from the hydraulic pump 102 flows from the first inlet port 201 through the first outlet port 202 into the control valve 110, flows out from the control valve 110, and passes through the flow rate control valve 260. Reflux from the second inlet port 203 to the tank 101 through the second outlet port 204. When the steering wheel is turned to the right, the third and fourth variable throttles 113, 114 of the control valve 110 are throttled, and the first and second variable throttles 111, 1
Since 12 is opened, the high pressure hydraulic oil is
The thick arrows shown in (b) and (c) flow, and the low-pressure hydraulic oil flows like the thin arrows shown in FIGS. 4 (d), (e), and (f). That is, as shown by the broken line arrow in FIG. 7, the high-pressure hydraulic fluid is guided to the second pressure chamber 124 of the power cylinder 120 through the first variable throttle 111 and the second switching valve 220, and the first pressure Low pressure hydraulic oil in chamber 123
Reflux to the tank 101 through the switching valve 210, the second variable throttle 112 and the flow control valve 260. Then, the pressure in the second pressure chamber 124 rises, the piston 122 is biased to the left in FIG. 7, and the steering wheel operating force is assisted. In the case of steering the steering wheel to the left, the reverse operation is performed.

In the case of automatic right-turn steering, the rotary valve 283 is rotated 60 ° counterclockwise from the neutral position as shown in FIGS. 3 (I) to (III) and FIGS. 5 (a) to (f). is there. That is, the first inlet port 201 and the first outlet port 2
02 communicates with each other through the passage 294, the annular outer peripheral groove 285 and the passage 295, and the second inlet port 203 and the second outlet port 204 are connected to the passage 27.
7, through the annular outer peripheral groove 286 and the passage 279. This communication state is the same as that in the manual steering described above, but in the automatic steering, the discharge pipe 14 is operated by the flow control valve 260 (Fig. 1).
The flow passage area of (Fig. 1) is narrowed so that the hydraulic fluid does not substantially flow through the control valve 110 (Fig. 1).

In addition, the first inlet port 201 includes the passage 294 and the annular outer peripheral groove 28.
5, passage 298, radial holes 289,288 annular peripheral groove 284 and passage
The port 222 of the first switching valve 210 communicates with the port 222 of the second switching valve 220 via 293.
Second outlet port via radial holes 291,290 and passage 279
Connect to 204. That is, in FIG. 1, the first and second switching valves 210 and 220 are in the second position different from that shown.
Therefore, as indicated by the broken line arrow in FIG. 8, the high-pressure hydraulic oil discharged from the hydraulic pump 102 passes through the discharge pipe 12 through the third and second passages 253 and 252 and the communication pipe 19 to the power cylinder 120. The low-pressure hydraulic oil in the first pressure chamber 123 is introduced into the second pressure chamber 124, and the low-pressure hydraulic oil in the first pressure chamber 123 flows through the communication pipe 18, the first and fourth
Return to tank 101 through passages 251, 254 and return pipe 15. Then, the pressure in the second pressure chamber 124 rises, 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 has a small opening degree, so most of the hydraulic fluid flows in the rotary valve section as indicated by the broken line arrow in FIG. No flow through valve 110. The amount of hydraulic oil flowing through the control valve 110 decreases as the opening degree of the flow control valve 260 decreases. Therefore, the pressure difference between the first and second pressure chambers 123 and 124 in the automatic steering mode, that is, the force that displaces the piston 122 increases as the opening degree of the flow control valve 260 decreases.

In the case of automatic left-turn steering, in contrast to right-turn automatic steering, the rotary valve 283 is at a position rotated 60 ° clockwise from the neutral position as shown in FIGS. 6 (a) to (f). 9
As shown, the first, second and third switching valves 210, 22
0 is in the second position. Therefore, the high-pressure hydraulic fluid discharged from the hydraulic pump 102 is the first pressure chamber 123 of the power cylinder 120.
And the low pressure hydraulic oil in the second pressure chamber 124 is supplied to the tank 101.
Reflux to. Then, the pressure in the first pressure chamber 123 becomes higher than that in the second pressure chamber 124, the piston 122 is biased 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 fluid is guided to the first or second pressure chamber 123, 124 of the power cylinder 120 to urge the piston 122, which automatically operates even if the driver does not operate the steering wheel. Right turn or left turn steering is 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 fluid is pumped into the second pressure chamber 124 of the power cylinder 120 by the right-turn automatic steering, and the piston 122 is biased in the direction of the thin arrow P. At the same time, the piston is turned by the driver's left-turn steering.
122 is biased in the direction of the thick arrow Q. Assuming that the relief valve 270 is not provided, the pressure in the second pressure chamber 124 rapidly increases because the high-pressure hydraulic oil is continuously supplied to the second pressure chamber 124 by the right-turn automatic steering. Not only will steering to the left be impossible, but the steering wheel will suddenly turn to the right, which is dangerous for the driver. This becomes remarkable as the steering is performed in the direction opposite to the automatic steering direction. However, in the present embodiment, the discharge pipe 12 and the return pipe 15 are connected by the relief pipe 21, and the relief pipe 270 is provided with the relief valve 270.
The relief pipe 21 is designed to be opened when the pressure on the upstream side of the relief valve 270 in 1 exceeds a set value. The upstream side of the relief valve 270 of the relief pipe 21 is in communication with the second pressure chamber 124 via the third and second passages 253, 252, the control pipe 17 and the communication pipe 18 in the case of right-turn automatic steering, that is, the first pressure chamber 124. The pressure is the same as that of the two pressure chambers 124. Therefore, the relief valve 270 opens the relief pipe 21 when the pressure in the second pressure chamber 124 becomes equal to or higher than the set value, and the relief valve 270
The amount of high-pressure hydraulic oil supplied to the pressure chamber 124 is limited, and the pressure in the second pressure chamber 124 is suppressed to a set value or higher. As a result, the driver can perform left-turn steering, although a relatively large steering force is required.

FIG. 11 shows a case where the driver performs right-turn steering during automatic right-turn 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 by the right-turn automatic steering, and the piston 122 is moved in the direction of the thick arrow Q by the driver's right-turn steering. I'm about to move. That is, the steering force of the driver's steering wheel is assisted by the pressure of the high-pressure hydraulic oil,
The driver can perform right-turn steering with a small steering force.

As described above, in the present embodiment, the rotary valve 283 is rotated by the motor 240 to three kinds of positions, whereby manual steering, automatic right-turn steering and automatic left-turn steering are switched, and flow rate control is performed during automatic steering. The pressure in the power cylinder 120 is prevented from becoming too high by the relief valve 270 even if the high pressure operating shaft is guided to the power cylinder 120 by narrowing the exhaust pipe 14 by the valve 260 and the manual steering is simultaneously performed during the automatic steering. This prevents manual steering from becoming impossible. Rotary valve like this
The switching and control of 283, the opening control of the flow control valve 260, and the relief pressure control of the relief valve 270 are performed by the control circuit 300 including a microcomputer.

FIG. 12 shows a flow chart of a control program by the control circuit 300. This control program may be started at the same time when the vehicle starts running, or may be started by the driver turning on a manual switch (not shown). Also, when starting this control program,
The rotary valve 283 may be in the neutral position, that is, in the state of manual steering, or in the state of automatic steering to the right or left.

This control program is interrupted, for example, every 200 msec. In step 401, the set distance D ₀ is read. The set distance D ₀ is a target value of the distance between the guide and the vehicle that is the reference of the travel route. For example, when the vehicle 21 is run along the guide 22 located on the side surface of the vehicle 21 as shown in FIG. 13, the set distance D ₀ is the distance between the axle and the guide 22,
Vehicle along line 23 on the road as shown in Figure 14
When traveling 21, the set distance D ₀ is the distance between the axle and the line 23 (for example, D ₀ = 0 may be used). This set distance D ₀ is
It may be determined in advance by a program, or may be set manually by the driving vehicle when the control program is started.

In step 402, the current vehicle speed V and the distance D from the guide are read. The vehicle speed V is detected by the vehicle speed sensor 303, and the distance D is detected by the position sensor 301.
Next, at step 403, the set throttle amount Q ₀ of the flow control valve 260, the set relief pressure S ₀ of the relief valve 270, and the set steering angle θ ₀ are calculated based on the current vehicle speed V. It is safer to increase the steering force and decrease the steering speed as the vehicle speed V increases. Therefore, the set throttle amount Q ₀ , the set relief pressure S ₀ , and the set steering θ ₀ are set to decrease as the vehicle speed V increases.

Automatic steering is performed when the difference (D-D ₀ ) between the current distance D from the guide of the vehicle and the set distance D ₀ is 0, that is, when the vehicle is traveling along a predetermined route. There is no need, and the program proceeds from step 404 to step 412, and after switching to the manual steering state, the flow control valve 260 is turned off, that is, fully opened in step 413, and the process ends. On the other hand, when the difference (D−D ₀ ) is not 0, that is, when the vehicle deviates from the predetermined traveling route, the process proceeds from step 404 to step 405.

In step 405, the flow control valve 260 is turned on. That is, the flow rate control valve 260 is throttled to the set throttle amount Q ₀ determined in step 403. In step 406, it is determined whether the difference (D-D ₀ ) between the current distance D from the guide and the set distance D ₀ is a positive value or a negative value. When the difference (D−D ₀ ) has a negative value, the vehicle is traveling on the left side of the determined travel route, so the routine proceeds to step 407, and right-turn automatic steering is performed.
That is, the rotary valve 283 is switched to the states shown in FIGS. On the contrary, when the difference (D−D ₀ ) has a positive value, the vehicle is traveling on the right side of the determined traveling route, so the routine proceeds to step 408, and left turn steering is performed. That is, the rotary valve 283 is switched to the states shown in FIGS. 6 (a) to 6 (f).

Next, at step 409, the pressure S acting on the relief valve 270 detected by the pressure sensor 302 and the steering angle sensor 304
The current steering angle θ detected by is read. Step
At 410, it is judged if the difference (S−S ₀ ) between the pressure S and the set relief pressure S ₀ is 0 or more. When the difference (S−S ₀ ) has a negative value, that is, when the pressure S acting on the relief valve 270 is smaller than the set relief pressure S ₀ , the driver can perform manual steering during this automatic steering. Therefore, the automatic steering is continued and the process proceeds to step 411. On the other hand, the difference (S
-S ₀ ) takes a value of 0 or more, that is, the relief valve 27
When the pressure S acting on 0 is equal to or higher than the set relief pressure S ₀ , the process proceeds to step 412, the state is switched to the manual steering state, and the flow control valve 260 is turned off, that is, fully opened. As described with reference to FIG. 10, when the direction of automatic steering is opposite to the direction of manual steering, the pressure acting on the relief valve 270 rises, the relief valve 270 opens, and the power cylinder 120
Although it is configured to prevent the pressure in the pressure chambers 123 and 124 from rising, the control program switches to the manual steering state to improve safety.

On the other hand, when the process proceeds from step 410 to step 411, the difference (θ−θ ₀ ) between the current steering angle θ and the set steering angle θ ₀ is 0.
It is determined whether or not. If this difference (θ−θ ₀ ) is not 0, the current steering angle θ has not yet reached the set steering angle θ _0, and therefore steps 412 and 413 are performed in order to maintain the current state of the rotary valve 283 for further steering. To end this program. On the other hand, if the difference (θ−θ ₀ ) is 0, the current steering angle θ has reached the set steering angle θ ₀ , so step 412 is executed to switch to manual steering and automatic steering is performed. Upon completion, the flow control valve 260 is turned off, that is, fully opened in step 413.

Thus, for example, when the right-turn automatic steering is performed, the control program is interrupted every 200 msec and executed in the order of steps 401, 402, 403, 404, 405, 406, 407, 409, 410, 411, and the steering angle θ gradually approaches the set steering angle θ ₀ , during that time. The distance D from the vehicle guide is set to D ₀
When it reaches, the process proceeds from step 404 to steps 412 and 413, and the manual steering state is switched. Further, the distance D is the set distance D ₀
When the steering angle θ matches the set steering angle θ ₀ before reaching
The control program executes steps 412 and 413 after step 411 to switch to manual steering, and controls so that the steering angle θ does not exceed the set steering angle θ ₀ .

That is, in the automatic steering mode, the right-turn or left-turn automatic steering is always performed so that the distance D from the guide of the vehicle becomes the set distance D ₀ , and the steering angle θ does not exceed the set steering angle θ ₀ during this period. Has become. On the other hand, the driver performs manual steering during the automatic steering, and the relief valve
When the pressure S acting on 270 becomes equal to or higher than the set relief pressure S ₀ , the process moves from step 410 to steps 412 and 413, and the manual steering state is switched.

The set steering angle θ ₀ is determined according to the vehicle speed V so that the vehicle does not spin. Further, the steering speed in the automatic steering mode is controlled by determining the set throttle amount Q ₀ of the flow rate control valve 260 according to the vehicle speed V, thereby preventing a sudden steering. Further, a relief valve 270 is provided, and in the automatic steering mode, the driver performs manual steering to set the pressure S of the relief valve 270 to the set relief pressure S.
_When it becomes ₀ or more, the relief valve 270 is opened to prevent the steering force from becoming abnormally large, and the mode is switched to the manual steering mode in which a so-called power steering action is obtained. When the driver steers in the same direction as the automatic steering, the pressure S does not rise, so the relief valve 270
Does not work, and the steering force is assisted by 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 cross wind. That is, a crosswind sensor for detecting a crosswind is attached to the vehicle, and when the vehicle receives a disturbance such as a crosswind or a gust of wind, the disturbance prevents the traveling direction from changing in advance.

The control program shown in FIG. 15 is the same as the control program shown in FIG. 12 except for the cross wind. That is, steps 501, 505, 507, 508, 509, 512, 513 perform exactly the same processing as steps 401, 405, 407, 408, 409, 412, 413, respectively.

In step 502, the current vehicle speed V, the distance D 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, a vehicle deviation D ₁ due to cross wind, a set throttle amount Q ₁ of the flow control valve 260, a set relief pressure S ₁ of the relief valve 270, and a set steering angle θ ₁ are calculated. To do. Step 504
Then, the difference (D−D ₁ −D ₀ ) obtained by subtracting the vehicle displacement D ₁ due to crosswind and the set distance D ₀ from the current distance D from the guide of the vehicle.
Is determined to be 0 or not. Here, the setting mechanism D ₀ is a distance between the guide and the target travel route of the vehicle, and takes a positive value when the target travel route is on the right side of the guide, and the distance D is positive when the vehicle is on the right side of the guide. It takes a value, and the deviation D ₁ has a positive value when the vehicle is located on the right side of the target travel route.
When it is determined in step 504 that the difference (D−D ₁ −D ₀ ) is 0, the vehicle is traveling on a predetermined route including the influence of cross wind, and there is no need for automatic steering. Move to switch to manual steering state and step
At 513, the flow control valve 260 is turned off and the program ends. In contrast, when the difference (D-D ₁ -D ₀₎ is not zero, in order to the automatic steering, executes step 505 following.

In step 505, the flow control valve 260 is turned on and the set throttle amount is set.
Focus on Q ₁ . In step 506 the difference (D-D ₁ -D ₀₎
Is determined to be a positive value or a negative value, and if it takes a negative value, right turn automatic steering is performed in step 507, and if it takes a positive value, left turn automatic steering is performed in step 508.

At step 509, the pressure S acting on the relief valve 270 and the steering angle θ are read. At step 510, it is determined whether the difference between the set relief pressure S ₁ and pressure S (S-S ₁₎ is 0 or more,
If this difference (S-S ₁₎ takes a negative value, to continue the automatic steering state, proceeds to step 511, if the difference (S-S ₁₎ takes a value of 0 or greater, executes step 512 and 513 Switch to the manual steering state and turn off the flow control valve 260.

When the process proceeds from step 510 to step 511, it is determined whether or not the difference (θ-θ ₁ ) between the current steering angle θ and the set steering angle θ ₁ is 0, and this difference (θ-θ ₁ ) is not 0. In this case, steps 512 and 513 are skipped to end the program in order to maintain the current automatic steering state. On the other hand, the difference (θ-θ
_{If 1} ) is 0, steps 512 and 513 are executed to switch to the manual steering state and the flow control valve 26
Set 0 to OFF.

As described above, according to the control program of FIG. 15, the influence of cross wind is also taken into consideration, and when the cross wind is detected, the positional deviation D ₁ of the vehicle due to the cross wind is calculated in advance so that this deviation D ₁ does not occur. Automatic steering is performed. Further, the set throttle amount Q ₁ of the flow control valve 260, the set relief pressure S ₁ , and the set steering angle θ ₁
Is determined in consideration of the influence of cross wind. As a result, smoother steering is possible and driving safety is improved.

16 to 18 show another embodiment of the drive source of the rotary valve section 200. That is, the rotary valve unit 200 was driven by the motor 240 in the above-described embodiment, but in the present embodiment, the gear type hydraulic motor 6 using the piezo actuator 601.
Driven by 00. Drive shaft 602 and driven shaft 603 are body 60
They are housed in 4 and arranged in parallel with each other, and are rotatably supported around their respective axes. The drive shaft 602 projects into the body 280 of the rotary valve section 200, and the rotary valve is attached to the projecting end.
283 is fixed. 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 gear 606 provided on the drive shaft 602 and a driven gear 607 provided on the driven shaft 603.
Mesh with each other. The meshing portions of these gears 606 and 607 face the inside of an oil passage 608 formed in the body 604. Therefore, when the hydraulic oil flows in the oil passage 608, the drive gear 6
06 and the driven gear 607, that is, the drive shaft 602 and the driven shaft 603 rotate around the shaft center, whereby the rotary valve 283 and the rotary encoder 605 rotate.

The piezo actuator 601 is formed by stacking 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 has a bore 6
It is fixed in 12 and a piston 613 is attached to the lower end. Pump 614 formed by piston 613 and bore 612
Is provided with a disc spring 615, and the disc spring 615 has a piston 61
The 3 is urged in the direction of coming into contact with the piezo actuator 601. The piezo actuator 601 is connected to the control circuit 300 (FIG. 1) via a lead wire 616.
Power is supplied or cut off by 00 to expand and contract. The rotary encoder 605 is also connected to the control circuit 300.

Plunger 62 is placed in valve hole 621 that communicates with pump chamber 614.
2 is slidably accommodated. Valve hole 621 is a hydraulic pump
It is also possible to communicate with the inlet port 623 leading to 102 (FIG. 1) and the oil passage 608. The plunger 622 has an annular groove 624 on its outer peripheral surface and a conical seat portion 625 at its end.
The annular groove 624 faces the throttle passage 626 that communicates with the pump chamber 614 and the inlet port 623, and the seat portion 625 can be brought into close contact with the conical seat surface 627 formed at the end of the valve hole 621. In the plunger 622, the seat portion 625 is seated on the seat surface 627 by the spring 628.
The seat portion 625 is in close contact with the seat surface 627 when it is not in operation.
Is blocked from the input port 623.

Then, when the piezo actuator 601 is energized and expanded, the pump chamber 614 contracts, and the hydraulic oil in the pump chamber 614 displaces the plunger 622 in the direction of arrow R against the spring 628 as shown in FIG. . As a result, the seat portion 62
5 is separated from the seam surface 627, and the annular groove 624 faces 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, and flows into the oil passage 608.
It flows out from the output port 629 through the meshing portion of 607. As a result, the gears 606 and 607, that is, the drive shaft 602 and the driven shaft 603 rotate, and the rotary valve 283 rotates. Also,
Along with this, the rotary encoder 605 also rotates, and a signal indicating this rotation angle is input to the control circuit 300. Then, the control circuit 300 detects the signal and energizes the piezo actuator 601 to rotate the rotary valve 283 by a predetermined angle.

As described above, in the present embodiment, the hydraulic oil flows through the oil passage 608.
Since the fluid flows in one direction, the drive shaft 602 and the rotary valve 283 rotate only in one direction to switch between manual steering and automatic steering.

The stars of the rotary valve unit 200 are shown in FIGS.
The configuration is the same as II).

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

〔The invention's effect〕

As described above, according to the present invention, it is possible to obtain a steering device having a simple and small structure and capable of performing reliable automatic steering.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram showing an embodiment of the present invention, and FIGS. 2 (I), (II), and (III) are sectional views showing a rotary valve portion in a manual steering state, and FIG. 2 (I). Is a sectional view taken along the line I ₂ -I ₂ of FIG. 4 (a), FIG. 2 (II) is a sectional view taken along the line II ₂ −II ₂ of FIG. 4 (a), and FIG.
I) is a cross sectional view taken along the III ₂ -III _2-wire 4 (a), FIG. 3 (I), (II), (III) is a sectional view showing a rotary valve portion of the right turn automatic steering state 3 (I) is a sectional view taken along line I ₃ -I ₃ of FIG. 5 (a), and FIG. 3 (II) is a sectional view taken along line II ₃ -II ₃ of FIG. 5 (a). , Fig. 3 (II
I) The fifth view sectional view taken along III ₃ -III _3-wire (a), FIG. 4 (a) ~ (f) is Fig. 4 a sectional view showing a rotary valve and the tubular liner in the manual steering state 2A is a sectional view taken along line AA in FIG. 2I, FIG. 4B is a sectional view taken along line BB in FIG. 2I, and FIG. FIG. 2 (I) is a sectional view taken along the line CC, FIG. 4 (d) is a sectional view taken along the line DD of FIG. 2 (I), and FIG. I) sectional view taken along the line EE, FIG. 4 (f) is a sectional view taken along the line FF of FIG. 2 (I), and FIG. 5 (a) to (f) are right cut automatic 5A is a cross-sectional view showing the rotary valve and the tubular liner in a steering state, FIG. 5A being a cross-sectional view taken along the line AA of FIG. 3I, and FIG. 5B being FIG. 3I. 5 is a sectional view taken along line BB of FIG. 5, FIG. 5 (c) is a sectional view taken along line CC of FIG. 3 (I), 5 (d) is a sectional view taken along the line D-D in FIG. 3 (I), FIG. 5 (e) is a sectional view taken along the line E-E in FIG. 3 (I), and FIG. 5 (f). Is a cross-sectional view taken along the line FF in FIG. 3 (I), and FIGS. 6 (a) to 6 (f) are cross-sectional views showing the rotary valve and the tubular liner in the left-turn automatic steering state. a) is a cross-sectional view at the same height as FIG. 5 (a), FIG. 6 (b) is a cross-sectional view at the same height as FIG. 5 (b),
FIG. 6 (c) is a sectional view at the same height position as FIG. 5 (c), FIG. 6 (d) is a sectional view at the same height position as FIG. 5 (d), and FIG. 6 (e). Fig. 5 (e) is a sectional view at the same height position, 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 a manual steering state. Fig. 8 is a hydraulic circuit diagram showing a right-turn automatic steering state, Fig. 9 is a hydraulic circuit diagram showing a left-turn automatic steering state, and Fig. 10 is a state showing a left-turn manual steering in the right-turn automatic steering state. Fig. 11 is a hydraulic circuit diagram showing Fig. 11 is a hydraulic circuit diagram showing a state in which a right turn manual steering is performed in a right turn automatic steering state, Fig. 12 is a flow chart showing an embodiment of a control program, and Fig. 13 is a guide line. Fig. 14 is a schematic diagram showing the case where the vehicle travels on the road surface. FIG. 15 is a schematic view showing a case of traveling, FIG. 15 is a flowchart showing another embodiment of the control program, FIG. 16 is a sectional view showing the rotary valve portion and the hydraulic motor, FIG. 17 is a horizontal sectional view showing the hydraulic motor, FIG. 18 is a horizontal sectional view showing an operating state of the hydraulic motor. 101 …… tank, 102 …… pump, 120 …… power cylinder, 121 …… cylinder bore, 122 …… piston, 123,124 …… pressure chamber, 125 …… rod, 200 …… rotary valve section, 210,220,230 …… first, first Second and third switching valves, 240 ... Motor, 260 ... Flow control valve, 270 ... Relief valve (pressure control means), 283 ... Rotary valve (automatic steering control means), 300 ... Control circuit.

Claims (3)

[Claims] 1. A rod is displaced according to a handle operation,
A steering device for steering left and right wheels connected to the rod, the power cylinder having two pressure chambers in which a piston fixed to the rod is slidably accommodated in a cylinder bore, and a traveling route. Setting means that determines the distance between the guide installed in the direction and the vehicle,
Automatic steering control means for supplying high pressure hydraulic oil to one pressure chamber and releasing hydraulic oil in the other pressure chamber to the tank in accordance with the steering direction determined by the setting means, and hydraulic oil supplied to the pressure chamber. And a pressure control means for limiting the supply of the hydraulic oil to the pressure chamber when the pressure of the hydraulic pressure exceeds a certain value. 2. A rod is displaced according to a handle operation,
A steering device for steering left and right wheels connected to the rod, the power cylinder having two pressure chambers in which a piston fixed to the rod is slidably accommodated in a cylinder bore, and a traveling route. Setting means that determines the distance between the guide installed in the direction and the vehicle,
In accordance with the steering direction determined by the setting means, automatic steering control means for supplying high pressure hydraulic oil to one pressure chamber and releasing the hydraulic oil in the other pressure chamber to the tank, and the power cylinder according to the steering wheel operation Power steering control means for supplying high pressure hydraulic oil to one pressure chamber and releasing the hydraulic oil in the other pressure chamber to the tank, and switching for selectively operating one of the automatic steering control means and the power steering control means Means, flow rate control means provided between the pressure chamber and the tank for changing the flow passage area, and manual steering during automatic steering, the pressure of the hydraulic oil in the pressure chamber does not exceed a certain value. An automatic steering mechanism for a steering device, comprising: a pressure control means for limiting the supply of hydraulic oil to the pressure chamber. 3. The flow rate control means relatively increases the flow passage area when the power steering control means operates, and relatively reduces the flow passage area when the power steering control means does not operate. The automatic steering mechanism for a steering device according to claim 2, wherein: