JPH0439167A - Automatic steering device for vehicle - Google Patents

Abstract

PURPOSE:To miniaturize a driving system by providing a control valve made of a four-way valve which has two input shafts concentrically arranged with respect to a steering shaft, is fixed with one input shaft to the steering shaft, and controls the feed and discharge of the pressure oil to a power cylinder. CONSTITUTION:A control valve 18 made of a rotary four-way valve is provided between lower and upper steering shafts 13a, 13b. An outer sleeve 18f, an inner spool 18g and a torsion bar section 13b3 are concentrically arranged in the case 18e of the control valve 18, and the lower end of the torsion bar section 13b3 is connected to the lower steering shaft 13a. The outer sleeve 18f is connected to the lower steering shaft 13a with a pin 18i. When an actuator drives an input shaft, a power cylinder 22 drives a steering link system in response to the feed and discharge of the pressure oil by the control valve 18, and the actuator which can generate only the driving force to drive the control valve 18 is sufficient for use.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an automatic steering system for a vehicle that drives a steering mechanism by an automatic steering drive mechanism under the control of an automatic steering control means to automatically steer a vehicle.

[Prior art]

Conventionally, as this type of device
The one disclosed in the above publication is known. According to this device, the rotating shaft of a servo motor connected to an automatic steering controller and a steering shaft are connected via a transmission mechanism consisting of gears, and the steering is performed using the driving force of the servo motor. [Problems to be Solved by the Invention] However, in the conventional device described above, the servo motor has to directly drive the rotation of the steering shaft, which naturally requires a large driving force, making the servo motor large and subject to restrictions on placement. The present invention was made in order to solve the above problems.
It is an object of the present invention to provide an automatic steering device for a vehicle that can reduce the size of a drive mechanism in an automatic steering control system to reduce restrictions on arrangement and also reduce costs.

[Means to solve the problem]

In order to achieve the above object, the structural features of the present invention are as follows:
A steering mechanism includes a steering shaft connected to a steering wheel connected to an input shaft of a steering link mechanism, and a hydraulic pump that supplies and discharges pressure oil to drive the steering link mechanism using the hydraulic power. A power cylinder and two cylinders arranged concentrically with respect to the above-mentioned steering shaft.
The control valve consists of a four-way rotary valve with two input shafts, one of which is fixed to the steering shaft, and controls the supply of pressure oil to the power cylinder, and an automatic control valve that controls the direction of travel of the vehicle. The present invention is configured to include a steering control means and an actuator that rotationally drives the other input shaft of the control valve in response to steering control by the automatic steering control means.

[Operation and effects of the invention]

In the present invention configured as described above, when the actuator drives the input shaft of the control valve under control by the automatic steering control means, the power cylinder operates the steering link mechanism in response to the supply of pressure oil by the valve. To drive the actuator l! An actuator that can generate enough driving force to drive the control valve is sufficient, and a small actuator can be used. Further, in addition to being able to use such a small actuator, the control valve is arranged concentrically with the steering shaft, so the present invention facilitates arrangement and reduces manufacturing costs.

【Example】

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. Fig. 2 schematically shows the entire front wheel steering S structure in which the automatic steering device for a vehicle according to the present invention is applied to a vehicle equipped with a steering mechanism in the front wheels. It shows. This front wheel steering mechanism is displaced in the axial direction to rotate the left and right front wheels FWI,
It has a rack bar 11 for steering the FW 2. rack bar
Left and right tie rods 16a 11 are connected to the steering handle 14 via the pinion gear 12, the lower steering shaft 13a, and the upper steering shaft 13b, and are swingably connected to rack ends 15a and 15b fixed at both ends thereof. 16b and the left and right front wheels FW via left and right knuckle arms 17a and 17b which are rotatably connected to the same tie rods 16a and 16b.
I and FW2 are connected. A control valve 18 consisting of a Rochley-type four-way valve shown enlarged in FIG. 1 is assembled between the lower steering shaft 13a and the upper steering shaft tab. The control valve 18 is housed in a case 18e that also serves as a gear box, and includes an outer sleeve 18f serving as one input shaft, an inner spool 18g serving as the other input shaft, and a torsion bar part 13b3 configured at the lower end of the upper steering shaft 13b. are arranged concentrically, and the lower end of the torsion bar part 13b3 is connected to the lower steering shaft 13.
The outer sleeve 18f is connected to the lower steering shaft 13a with a pin 18i, and the conduit P1 is connected to the hydraulic pot 21 according to the relative angle difference between the inner spool 18g and the outer sleeve 18f. The hydraulic oil supplied through the port 18a is transferred from the port h18b (or port 18c) to the right oil chamber 22 of the power cylinder 22.
At the same time, the hydraulic oil from the left oil chamber 22b (or right oil chamber 22a) of the cylinder 22 is introduced from port 18C (or port 18b) to port 18 (l). reservoir 23 via conduit P2.
discharge to. The outer sleeve 18f of the control valve 18 is connected to the lower steering shaft 1.
38 with a pin 181, the inner spool 18g is engaged with a sleeve 31 press-fitted into the drive section 30a of the servo motor 30 via a transmission mechanism 19 provided at the upper end of the control valve 18. , upper steering shaft 13b
It can be rotated freely. In addition, inner spool 18
When g rotates in the direction of the arrow in the figure and its relative angle with the outer sleeve 18f shifts, the ports 18a and 18b communicate with each other, the ports 18 (j and port 18c communicate with each other, and the inner spool 18g When the boat 88 and the boat 18c are rotated in the opposite direction to the arrow direction in FIG. A pressure oil discharge flow rate control mechanism (see Fig. 3) that limits the discharge amount of pressure oil in inverse proportion to the vehicle speed is provided between the pressure oil discharge amount control mechanism and the control valve 18. A flow rate control valve 24 that always discharges only a certain amount of hydraulic oil out of the hydraulic oil at a flow rate approximately proportional to the engine rotation speed discharged by the hydraulic pump 21 consisting of a vane pump, and an operation that is discharged from the flow rate control valve 24. A flow control valve 25 returns part of the oil to the reservoir 23 and controls the hydraulic oil discharged from the pressure oil discharge flow rate control mechanism so that it is inversely proportional to the vehicle speed; A second hydraulic pump 26 consisting of a trochoid pump that discharges hydraulic oil proportional to the vehicle speed in order to control the amount of discharged hydraulic oil that is returned to the reservoir 23.
It is composed of. The flow rate control valve 24 controls the flow rate of hydraulic oil passing through a spool 24b and the inside of the spool 24b in a hollow pipe body having a first output port 24a2 and a second output port 24a3, such as an input port 24al. Hydraulic oil input from the restricting throttle 24c and the spring 24 (I) that biases the spool 24b in one direction (input capo) 24al passes through the hollow spool 24b to the second output capo. )24a3
When the hydraulic oil is outputted from the input port 24al, the flow rate is restricted by the throttle 24c, and when the spool 24b is pressed downward in the drawing, a part of the hydraulic oil input from the input port 24al is transferred from the first output port 24a2 to the pipe. As a result of being discharged to the reservoir 23 via the flow rate control valve 24
A constant amount of hydraulic oil is always discharged from the engine regardless of engine speed. 7o-control valve 25 has first and second input ports 25 a 1. 25a2 and the first and second output ports 25a3. A spool 25b in a hollow pipe body having a diameter of 25a and 4, a throttle 25c that limits the flow rate of hydraulic oil passing through the spool 25b, and the spool 2.
5b in one direction, and a flow rate of hydraulic oil proportional to the vehicle speed discharged from the second hydraulic pump 26 is supplied from the first input port 25al through the hollow spool 25b. When the flow is output from the second output port 25a4, the flow rate is restricted by the throttle 25c, and when the spool 25t) is pressed downward in the drawing, the flow is discharged from the flow rate control valve 24, and the flow is discharged from the second input port 25a4. A part of the hydraulic oil input from the capo) 25a2 is transferred from the first output port 24a3 to the pipe P in proportion to the pressing force.
As a result of being discharged to the reservoir 23 via O, the hydraulic oil discharged from the pressure oil discharge flow rate control mechanism becomes approximately inversely proportional to the vehicle speed, as shown in FIG. A servo motor 30 that drives the inner spool 18g of the control valve 18 is fixed to the vehicle body through an outer case, and moves the sleeve 31 by a predetermined amount via the drive unit 30a in response to a control signal output from the motor control unit 32. It rotates in the forward and reverse directions, and when a positive control signal is output, it rotates in the direction of the arrow in Figure 1 by a rotation angle proportional to the current value of the same control signal, and when a negative control signal is output. rotates in the opposite direction to the direction of the same arrow. The motor control unit 32 includes a microcombi-9, and depending on the control mode selected by the mode switch 33, controls the first and second distance sensors 34a, 34b, the vehicle speed sensor 35, and the motor rotation angle sensor 36. automatic steering control that automatically steers the vehicle as shown in FIG.
Power assist control that assists steering wheel steering based on the weight specified by No. 8 is performed, and manual control that does not assist steering at all. Note that the distance sensor 34
a and 34b are provided on both the left and right sides of the vehicle, and are the distance xl from the guideline that serves as a reference for automatic steering to the side of the vehicle;
x2 (see Figure 5), and the same detection distance xlO,x2
A distance signal representing 0 is output respectively. Vehicle speed sensor 35
is provided near the transmission output shaft, detects the coaxial rotational speed as the roadway, and outputs a vehicle speed signal representing the detected vehicle speed 0. The motor rotation angle sensor 36 is connected to the servo motor 3
The rotation angle δ of the drive unit 30a at 0 is detected, and an angle signal representing the detected rotation angle δ0 is output. The steering/yaft rotation angle sensor 37 is provided near the upper steering shaft 13b, detects the rotation angle δf of the upper steering shaft, and outputs an angle signal representing the detected rotation angle δfo. In addition, as the vehicle speed increases, the vehicle speed V gradually becomes a larger positive value than "0", and the rotation angle δ and the rotation angle δf become "0" when traveling straight and become positive when turning in the right direction. When it becomes a large value and rotates in the left turning direction, it becomes a negative large value. Now, to explain the above automatic steering control, this control automatically steers the vehicle so that the center of two guidelines provided on the road surface is set as a target course, and the vehicle travels on the same course. , the distance from the side of the vehicle detected at 34b to the guideline is 1111! From xi and x2, the deviation amount 2 from the target course is calculated based on the calculation formula, and the deviation amount 2 and the rate of change of the deviation amount Δ2 (= j
! The IX rotation angle δ* of the servo motor 30 corresponding to the amount of steering for traveling on the target course is calculated based on the following: new -2 old). After calculating the target rotation angle δ*, the difference between the target rotation angle δ* and the current rotation angle δ0 of the servo motor 30 is calculated, and the servo motor 30 is driven so as to eliminate the need to open the lid. Note that the microcomputer in the motor control section 32 is
Along with programs corresponding to various controls, maps of parameters and coefficients necessary for executing the programs are stored in advance, and this motor control unit 32 and various switches,
The automatic steering control unit is composed of the engine and the sensors. Now, the power cylinder 22 to which hydraulic oil is supplied and discharged by the control valve 18 is operated according to the supply and discharge of the hydraulic oil.
1 in the axial direction, and assists the driver in steering the left and right front wheels FWI, FW by the steering wheel 14 or by the servo motor 30 controlled by the motor control unit 32. However, a switching valve 27 is provided between conduits PI and P2 in the hydraulic drive system, and the switching valve 27 responds to control by the motor control unit 32 or instructions from a safety switch 39 connected to the control unit. When the motor controller 32 or the servo motor 30 is abnormal (when turned off), it becomes quiet and shuts off the conduits PI and P2 to assist front wheel steering by hydraulic pressure. Conduit PI, P
By communicating between the two, it is possible to prevent an unreasonable load from being placed on the driver's corrective steering. Next, the operation of the above embodiment will be explained. Assume that the driver has selected the automatic steering mode using the mode switch 33, and that the vehicle has deviated to the right from the target course. After performing the initial setting process, the microcomputer in the motor control section 32 repeatedly executes a program corresponding to the flowchart shown in FIG. If the front wheel steering is assisted by hydraulic pressure when the drive control of the servo motor 30 is not normal, it will be necessary to use the steering wheel 14 to steer against the same hydraulic pressure. It is determined whether there is an abnormality in the control system 300, and if there is no abnormality, the mode selection status by the mode switch 33 is determined in step 110 [) and control corresponding to each mode is executed. Since the automatic steering mode is currently selected, the process moves to Step 1200, where the switching valve 27 is turned on and the pipe line PI is turned on.
, P2, and executes the automatic steering motor routine in step 1300. In the automatic steering motor routine (see Figure 7), first,
Vehicle speed v detected by vehicle speed sensor 35 in step 1310
O and the motor rotation angle δ detected by the motor rotation angle sensor 36
0 and the distance xlo detected by the distance sensors 34a and 34b,
Input each x20 detection data. After each detection data is obtained, in step 1320 (1
) Based on the distance xlO, x20, the current deviation Q from the target course (hereinafter, deviation 2 or deviation 52 new
It is expressed as ) is calculated. Now, since the vehicle is off to the right from the target course, the distance xlO detected by the left distance sensor 34a is longer than the distance x detected by the right distance sensor 34b.
20, the deviation Rnav becomes a negative value. While the automatic steering mode is in effect, the deviation It new is repeatedly calculated in step 1320, and in step 1330, the following equation is calculated using the thus calculated deviation new and the previously calculated old deviation Q old. 2 is calculated based on the rate of change of deviation. ΔQ=Rnev-P! old -(
2) When the deviation Ωnew is calculated for the first time after entering the automatic steering mode, the old deviation Rold becomes rOJ, and the change rate Δ of the deviation becomes rRnewJ. Once the deviation Ω and the deviation change rate Δ2 are calculated, step 1
The deviation It new calculated this time at 340 is the old deviation II
vehicle speed vO in step 135o.
Coefficient kl (=f
k1m), ni2 (=fk2m). Read k 3 (-f kl(V)). These coefficients are all read out according to the detected vehicle speed VO, and are "0" or positive values. On the other hand, in step 1360, the target rotation angle δ* of the servo motor 30 is calculated according to the following equation. δ*=1・2+2・Δ9 − (3) In this case, the deviation 2 is negative, the rate of change of deviation Δ is negative, and kl is 2≧
Since there is a relationship of 0, the target rotation angle δ* is a negative value. After the target rotation angle δ* is calculated, in step 1370, the rotation angle δ0 of the servo motor detected by the motor rotation angle sensor 36 in step 1310 and the target rotation angle δ* are calculated.
The drive signal l of the servo motor 30 is set by multiplying the lid opening by a predetermined multiplication coefficient by 3. Incidentally, since the servo motor 30 should have been in the neutral position up to now, the rotation angle δ0 should be "0", and the drive signal ■ will have a negative value. When step 1370 is completed, the process returns to the main routine, and in step 1400, the set drive signal I
is output to the servo motor 30. Since this drive signal (2) is negative, the servo motor 30 rotates the sleeve 31 in the direction opposite to the direction of the arrow in FIG. When the sleeve 31 rotates in the direction opposite to the arrow direction in FIG. 1, the inner spool 18g engaged with the sleeve 31
The upper end also rotates in the direction opposite to the direction of the arrow shown in FIG. 1, bringing the boats 18a and 18c into communication, and the boats 18d and 18b into communication. Therefore, the high-pressure hydraulic oil supplied from the hydraulic pump 21 passes from the boat 18a to the boat 18c to the power cylinder 2.
Since the oil is supplied to the left oil chamber 22b of the bow cylinder 2,
2 moves the piston 22c in the power cylinder 2 to the right in FIG.
It is discharged to 3. Piston 2 in bow cylinder 2-2
When 2C moves to the right, tie rods 16a and 16b
and the left and right front wheels FW via the knuckle arms 17a and 17b.
Since I and FW2 are steered to the left, the front wheel steering lick mechanism is activated simply by rotating the inner spool 18g by the small servo motor 3o, and the steering by the servo motor 3o is performed by the hydraulic mechanism. You will be helped. Also, as the power cylinder 22 moves,
The C-binion 12 is rotated in the same direction as the inner spool 18g in FIG. As the lower steering shaft 13a fixed to the lower steering shaft 13B rotates due to the rotation of the same binion 12, the outer sleeve 18f, which is engaged with the lower steering shaft 13B with a pin, also rotates by a predetermined amount. The hydraulic mechanism continues to assist steering until the rotation of the inner spool 18f catches up with the rotation of the inner spool 18g (until the relative angle difference disappears). On the other hand, since the front wheels FWI and FW2 of the vehicle are steered to the left, the vehicle is steered to the left and approaches the target course. If the vehicle deviates to the right from the target course, the vehicle is controlled to be displaced to the left as described above, and the vehicle gradually approaches the target course. In step 1500, it is determined whether or not to continue the control. If the control is not to be stopped (control is to be continued), the above process is repeated; if it is determined to be stopped, the process is performed in step 1600. Perform post-processing and stop control. In the above-described processing, it is assumed that the vehicle deviates to the right from the target course, but when the vehicle deviates to the left from the target course, the following occurs. First, in step 1310, the detection data detected by each sensor is input, and in step 1320, the deviation 2 from the target course is calculated from the distance MxlO,x20 based on equation (1). Because it is shifted to
The distance xlO detected by the left distance sensor 34a is smaller than the distance x20 detected by the right distance sensor 34b (the deviation 2 is a positive value. In step 1330, this calculated deviation 2 new and the previously calculated old deviation 9 old
The rate of change Δρ of the deviation is calculated based on equation (2). Assuming that the previous deviation 2 was "0", the rate of change Δp is [2new j]. Once the deviation 2 and the deviation change rate Δ2 are calculated, step 1
The deviation 2 new calculated this time at 340 is the old deviation ρol
d, and in the STEP 1350, the coefficient kl (=
fkl (V)), 2 (= fk2m), 3 (= f
kim). Since all of these coefficients are "0" or positive values, step 4. At the block 1360, the target rotation angle δ* of the servo motor 30 is determined based on equation (3).
When the target rotation angle δ* is calculated, the target rotation angle δ* becomes a positive value. Once the target rotation angle δ* has been calculated, step 1370 outputs a drive signal for the servo motor 30! Set. In addition, assuming that the servo motor 30 is in the neutral position in this case as well,
The rotation angle δ0 is "0", and the drive signal ■ has a positive value. After step 1370 is completed, the process returns to the main routine, and in step 1400, the drive signal set above is output to the servo motor 30. Since this drive signal I is positive, the servo motor 30 rotates the sleeve 31 in the direction of the arrow in FIG. When the sleeve 31 rotates, the upper end of the inner spool 18g engaged with the sleeve 31 also rotates in the direction of the arrow in FIG. and port 1
8b communicates with the boat 18d and the port 18.
It communicates with C. Therefore, the high-pressure hydraulic oil supplied from the hydraulic pump 21 is passed from the boat 18a to the bown cylinder 2 through the port 18b.
Power cylinder 2 is supplied to the right oil chamber 22a of power cylinder 2.
The piston 22c in the bow cylinder 22 is moved to the left in FIG.
It is discharged to 3. Piston 22 in power cylinder 22
When C moves to the left, the left and right front wheels FWI
, FW2 is steered to the right, so in this case as well, the steering by the servo motor 30 is assisted by the hydraulic mechanism until the rotation of the outer sleeve 18f catches up with the rotation of the inner spool 18g. In this way, in the automatic steering mode, the motor control unit 32 controls the servo motor 30 based on the detection results of each sensor.
As a result, the servo motor 30 rotates the inner spool of the control valve 18 by a predetermined amount, and the power cylinder 2
2 drives the steering link mechanism, and the vehicle is steered. Although the above example has been explained assuming that there is no abnormality in the control system, if any abnormality is determined by the motor control section 32, step 10 in the control process that is repeatedly executed
It is determined that there is an abnormality at step 00, and the switching valve 2 is switched off at step 1700.
7 is turned off, and a stop signal is output to the servo motor 30 in step 1800. The switching valve 27
is turned off, pipes P1 and P2 are connected, and high-pressure hydraulic oil is not supplied to the power-on cylinder 22 regardless of the relative positional relationship between the inner spool 18g and the outer sleeve 18f. In this case, the driver turns the steering wheel by steering the steering wheel 14, but the inner spool 18g engaged with the servo motor 30 moves from the steering wheel 14 to the upper steering shaft 13b and the tone gimbal. Since the servo motor 30 is rotatable relative to the rotation system that reaches the lower steering shaft 13a via the servo motor 18h, even if the servo motor 30 stops or an abnormality occurs, the driver will not be able to perform any steering operations. There is no effect. So far, the case of automatic steering has been explained, but in the vehicle in this example, automatic steering control is not performed, but pressure oil is supplied and discharged to and from the power cylinder 22 and power is controlled. If the manual mode is selected with the mode switch 33, in the main routine, after determining whether or not there is an abnormality in the control system in step 1000, Step 170 is performed in the same way as when it is determined that the mode selection is manual mode and that there is an abnormality in the control system.
At step 0, the switching valve 27 is turned off and step 180
At 0, a servo motor stop signal is output. That is, the driver can rotate the steering wheel 14 himself to operate the steering link mechanism and steer the front wheels. In addition, when selecting the power amp mode with the mode switch 33, the weight of the steering wheel during power assist can be set to "Low", "Medium" or
You need to select from ``High'', and the amount of power amps supported will increase sequentially as you go from ``Low'' to ``High''. For now, the explanation will be based on the assumption that "High" of the power amp mode is selected. When this power amp mode is selected, the mode selection judgment in step 1100 determines that it is the power assist mode, and after turning on the switching valve in step 1900, the power und motor routine is started at step 200. Execute. In this power undemonstration routine, step 20
At step 10, the vehicle speed VO detected by the vehicle speed sensor 35, the motor rotation angle δ0 detected by the motor rotation angle sensor 36, and the rotation angle δf detected by the steering shaft E angle sensor 37 are inputted. Once each detection data is obtained, step 2020 calculates the difference between the rotation angle δ0 of the servo motor 30 and the rotation angle δf of the steering/yaft as the deviation α. Subsequently, in step 2030, the weight designation by the weight designation switch 28 is determined, but "high" is currently selected, and in step 2040, the coefficient k 4 (f
Hm). The coefficient 4 itself shows a tendency to decrease as the vehicle speed increases, and the steering wheel weight designation becomes heavier (“low”).
As the weight of the handle becomes lighter (the "high" side), the weight becomes smaller. follow, t
The relationship is n(v)>rM(V)>fL(V). When 4 is read out as the coefficient, in step 2050, the coefficient is multiplied by 4 and the deviation α and set as the servo motor drive signal ■. The coefficient 4 is large when the vehicle speed is low, and it becomes large when the weight of the steering wheel is light, and when the coefficient 4 is large, the drive signal ■ becomes a large value, causing the servo motor 30 to rotate a lot. shall be. As the rotation angle of the motor 30 increases, the relative angle difference between the inner spool 18g and the outer sleeve 18f increases, and the amount of pressure oil supplied from the control valve 18 to the power cylinder 22 increases. The force applied to the drive becomes thick (and the handle becomes light. In other words, when the setting of the drive signal ■ in step 2050 is completed, the process returns to the main routine, and the set drive signal ■ is applied to the servo motor 30 in step 1400. As a result of the output, the relative angular deviation between the inner spool 18g and the outer rib 18h increases as described above, and the amount of pressure oil supplied to the power cylinder 22 increases, making panodling easier. If the time or the weight of the handle is heavy, the coefficient 4 will be small, and even if the drive signal I is output to the servo motor 30 in step 1400, the inner spool 18g will only be rotated a little and will not be supplied to the power cylinder 22. Since the amount of pressurized oil is small, it becomes difficult to operate the steering wheel. Note that even if an abnormality occurs in the automatic steering control system or power assist control system, if the abnormality is not detected in step 1000, the switching valve 27 is not turned off, and depending on the rotational position of the servo motor 30, the driver may
The steering wheel must be operated by overcoming the hydraulic pressure supplied to 2. However, this embodiment is equipped with a pressure oil discharge flow rate control mechanism, and as the speed increases, the flow rate of the discharged pressure oil decreases and the steering assistance provided by the hydraulic mechanism becomes smaller. The burden on the driver is small even when the steering wheel is turned over. On the other hand, since a small steering force is required at high speeds, even if the hydraulic pressure is small at high speeds, the small servo motor 30 can sufficiently perform steering. Furthermore, although the hydraulic pressure is large in the low speed range, it is sufficient to manually turn off the safety switch 39.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the main parts of the automatic steering system for a vehicle according to the present invention, FIG. 2 is a schematic configuration diagram of a front wheel steering mechanism to which the automatic steering system for a vehicle according to the present invention is applied, and FIG. 3 is a A schematic configuration diagram of the oil discharge flow rate control mechanism, Fig. 4 is a diagram showing the relationship between the pressure oil discharge flow rate controlled by the pressure oil discharge flow rate control mechanism and vehicle speed, and Fig. 5 is a diagram showing the steering control in automatic steering control. , and FIGS. 6 to 8 are flowcharts showing control in the motor control section. Explanation of symbols 11... Rack par 12... Binion, 13a,
13b... Steering shaft, 14... Handle, 16a, 1
6b... Tie rod, 17a, 17b... Knuckle arm, 18f... Outer sleeve, 18g...
・Inner spool, 18h...Torsion bar 21
... Hydraulic pump, 22 ... Power cylinder, 30.
...Servo motor, 32...Motor control section, 33...
・Mode switch, 34a, 34b...first and second
distance sensor, 35...vehicle speed sensor, 36...motor rotation angle sensor.

Claims (1)

[Claims] A steering mechanism includes a steering shaft connected to a steering wheel connected to an input shaft of a steering link mechanism, and a hydraulic pump that supplies and discharges pressure oil to drive the steering link mechanism using the hydraulic power. A power cylinder and two cylinders arranged concentrically with respect to the above-mentioned steering shaft.
The control valve consists of a rotary four-way valve with two input shafts, one of which is fixed to the steering shaft, and controls the supply and discharge of pressure oil to and from the power cylinder, and an automatic control valve that controls the running direction of the vehicle. An automatic steering system for a vehicle, comprising: a steering control means; and an actuator that rotationally drives the other input shaft of the control valve in response to steering control by the automatic steering control means.