JP3412643B2 - Automotive steering control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering control device for an automobile having a power steering mechanism for assisting a steering operation force and an automatic steering mechanism for automatically steering according to a running condition of the vehicle. is there.

[0002]

2. Description of the Related Art Conventionally, as disclosed in, for example, Japanese Unexamined Patent Publication No. 4-205505, a power having a power cylinder provided on a steering rod of a steering device and a spool valve for supplying / discharging hydraulic pressure to / from the power cylinder. In a steering control device for an automobile configured to assist a steering wheel operating force by a steering mechanism, a pair of hydraulic chambers are formed so as to face both ends of the spool valve, and pilot pressure is supplied to the hydraulic chambers. It is known that an automatic steering valve is provided to drive the spool of the spool valve in the axial direction thereof to perform automatic steering operation corresponding to the traveling condition of the vehicle. Further, a rotary valve is provided in the power steering mechanism instead of the spool valve.

[0003]

As described above, in the case where the supply / discharge control of the hydraulic oil to / from the power cylinder is executed through the rotary valve or the like constituting the power steering mechanism during the automatic steering operation, There is a problem that it is difficult to achieve both the function of applying an appropriate assisting force according to the operating force of the steering wheel and the function of setting the steering angle to an appropriate angle corresponding to the traveling condition of the vehicle.

That is, the rotary valve is a pressure control valve for controlling the pressure of the hydraulic oil supplied to the power cylinder in accordance with the operating force of the steering wheel, the engine speed, and the like. During the automatic steering operation, it is necessary to quickly operate the power cylinder in order to obtain excellent steering response and prevent the pressure of the hydraulic oil supplied to the power cylinder from becoming excessive. It has been difficult to provide the rotary valve with such a function.

For example, in order to operate the power cylinder quickly, as shown by the broken line in FIG. 12, when the supply pressure of the hydraulic oil is rapidly increased as the valve opening is increased, However, there is a problem that the maximum pressure of the hydraulic oil supplied to the power cylinder becomes too large. On the other hand, in order to suppress the maximum pressure,
As shown by the solid line in Fig. 2, when the hydraulic oil supply pressure is configured to gradually increase as the valve opening increases, the hydraulic oil must be quickly supplied to the power cylinder during automatic steering operation. There is a problem that you can not.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to rapidly supply the hydraulic oil to the power cylinder during the automatic steering operation, and the supply pressure of the hydraulic oil is An object of the present invention is to provide a steering control device for an automobile, which can prevent the steering control device from becoming too high.

[0007]

The invention according to claim 1 is
A power steering mechanism that assists the steering wheel operation force, an automatic steering mechanism that automatically performs steering according to the running condition of the vehicle, and a steering shaft that is driven by hydraulic oil supplied from the power steering mechanism or the automatic steering mechanism. A power steering system for an automobile, comprising: a common hydraulic pressure source for supplying hydraulic oil to the power steering mechanism and the automatic steering mechanism; and a hydraulic pressure source supplied to the power cylinder from the hydraulic source when the automatic steering mechanism operates. and a pressure control means for controlling the pressure of the operating oil, and provided to the power steering mechanism
Control valve for power steering and automatic steering mechanism
Installed in parallel with the control valve for automatic steering provided in
In addition, on the downstream side of this control valve for automatic steering,
The pressure of hydraulic oil supplied to the power cylinder is preset.
The pressure control means is provided to regulate the pressure below a specified reference value .

The invention according to claim 2 is based on the invention according to claim 1.
In a steering control device for a moving vehicle, an automatic steering mechanism is provided with pressure accumulating means for accumulating hydraulic oil supplied from a hydraulic pressure source, and hydraulic oil is supplied from the pressure accumulating means to the power cylinder during automatic steering operation.

The invention according to claim 3 is the same as the invention according to claim 1.
In a steering control device for a moving vehicle, a flow rate adjusting means is provided for adjusting the supply flow rate of the hydraulic fluid discharged from a hydraulic pressure source in accordance with the operating characteristics of the power steering mechanism, and the hydraulic fluid is controlled by the flow rate adjusting means during automatic steering operation. It is configured to regulate the flow rate adjusting action of.

The invention according to claim 4 is the invention according to claim 1.
The steering control device for a moving vehicle is provided with a flow rate adjusting means for adjusting the supply flow rate of the hydraulic oil discharged from the hydraulic pressure source according to the engine speed.

According to a fifth aspect of the present invention, there is provided a power steering mechanism for assisting an operating force of a steering wheel, an automatic steering mechanism for automatically steering according to a running condition of a vehicle, the power steering mechanism or the automatic steering mechanism. A steering device for an automobile, comprising: a power cylinder that drives a steering shaft with hydraulic oil supplied from a vehicle, wherein a common hydraulic pressure source for supplying hydraulic oil to the steering mechanism and the automatic steering mechanism is provided, and A pressure changing means is provided for changing the pressure of the hydraulic oil supplied from the source between when the power steering mechanism is operating and when the automatic steering mechanism is operating.

[0012]

According to the first aspect of the invention, the hydraulic oil discharged from the common hydraulic source is supplied to the power cylinder via the power steering mechanism or the automatic speed change mechanism,
At normal times, the hydraulic oil set to a pressure suitable for the operating state of the power steering is supplied to the power cylinder via the power steering mechanism, and an appropriate steering assist force is obtained. Further, during the automatic steering operation, the hydraulic oil controlled by the pressure control means to a pressure suitable for the automatic steering operation state is supplied to the power cylinder via the automatic steering mechanism to perform appropriate steering. During the automatic steering operation, the hydraulic oil supplied from the hydraulic source is supplied to the control valve for the automatic steering operation to control the flow path and the like, and then is supplied to the installation portion of the pressure control means to perform the automatic steering operation. It will be supplied to the power cylinder after being controlled to a pressure suitable for the condition.

According to the second aspect of the present invention, during the automatic steering operation, the hydraulic oil accumulated by the pressure accumulating means is rapidly supplied to the installation portion of the pressure control means via the control valve for the automatic steering operation. Will be.

According to the third aspect of the present invention, during power steering operation, the flow rate adjusting means adjusts the supply flow rate of the hydraulic oil in accordance with the operating characteristics of the power steering mechanism, thereby adapting to the operating state of the automobile. The steering assist force that has been obtained is obtained. Further, during the automatic steering operation, the operation of the flow rate adjusting means is restricted, and the hydraulic oil controlled to the predetermined pressure by the pressure control means is quickly supplied to the power cylinder.

According to the fourth aspect of the present invention, during power steering operation, the flow rate of the hydraulic oil is adjusted by the flow rate adjusting means, so that the steering assist force fluctuates in response to changes in the engine speed. Will be prevented.

According to the fifth aspect of the present invention, the working oil discharged from the common hydraulic source is supplied to the power cylinder via the power steering mechanism or the automatic speed change mechanism, and is adapted to the operating state of the power steering during normal operation. The pressure changing means sets the pressure of the hydraulic oil to an appropriate value so that the hydraulic oil having the above pressure is supplied to the power cylinder through the power steering mechanism. Further, during the automatic steering operation, the supply pressure of the hydraulic oil is changed by the pressure changing means to a value adapted to the automatic steering operation state, so that the automatic steering mechanism performs appropriate steering.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of an automobile steering control device according to the present invention. The steering control device controls a steering rod 1 that constitutes the steering device, a power cylinder 2 that slides and displaces the steering rod 1 in the axial direction, and a pressure of hydraulic oil supplied to the power cylinder 2. Power steering mechanism 3 for controlling the steering assist force applied to the steering rod 1.
An automatic steering mechanism 4 that controls the flow path of the hydraulic oil supplied to the power cylinder 2 to control the operating position of the steering rod 1, and a steering angle sensor 49 that detects the operation angle of the steering wheel are provided. ing.

The power cylinder 2 includes a cylinder body 5 fitted onto the steering rod 1, and a piston 8 fixed to the steering rod 1 to divide the interior of the cylinder body 5 into left and right hydraulic chambers 6, 7. Have Then, for example, when hydraulic oil is supplied to the hydraulic chamber 7 on the right side of the cylinder body 5, the hydraulic oil in the hydraulic chamber 6 on the left side is led to the outside so that the steering rod 1 slides to the left. It has become.

Further, the power steering mechanism 3 is
A hydraulic pump 9 driven by an engine (not shown), a hydraulic oil supply line 10 connected to a discharge port of the hydraulic pump 9, and a thermometer 1 provided on the supply line 10.
1, an oil filter 12 and a switching valve 13, a control valve 14 for power steering that controls the pressure of the hydraulic oil supplied to the supply line 10, a hydraulic chamber 6 for both the control valve 14 and the power cylinder 2, The hydraulic oil supply / discharge lines 15 and 16 connecting 7 to each other, the hydraulic oil discharge line 18 connecting the control valve 14 to the reserve tank 17, and the oil cooler 19 provided on the discharge line 18. Have

From the hydraulic pump 9 to the switching valve 1
3 and the hydraulic oil supplied to the control valve 14 for power steering via the supply line 10 is pressure-controlled by the control valve 14, and then via either one of the supply / discharge lines 15 and 16. Power cylinder 2
Is supplied to. Further, the hydraulic oil derived from the power cylinder 2 is discharged from the other of the supply / discharge lines 15 and 16 into the reserve tank 17 via the control valve 14.

The hydraulic pump 9 to the supply line 1
The temperature of the hydraulic oil discharged to 0 is measured by the thermometer 11, and the oil cooler 19 operates according to the measurement result, whereby the hydraulic oil is cooled to a predetermined temperature. ing.

Control valve 1 for the above power steering
As shown in FIGS. 2 to 4, a sleeve 4 is connected to a rotor 21 that is directly connected to an input shaft 20 that is a steering shaft and an output shaft 22 that is a worm shaft, and is also fitted onto the rotor 21. 23, and the connection ports 10a, 15a, 16a, 18 of the hydraulic oil supply line 10, the supply / discharge lines 15, 16 and the discharge line 18.
a rotary valve having a valve case 24 in which a is formed. And according to the operation force of the steering wheel by the this relative angle change between the rotor 21 and the sleeve 23 the torsion bar 25 by torsional deformation connecting the output shaft 22 and the input shaft 20 occurs,
The switching of the supply direction of the hydraulic oil and the pressure control are executed.

That is, when the steering wheel is held at a predetermined operation position and the sleeve 23 is in the neutral position shown in FIG. 3, the connection ports 15a and 16a of the supply and discharge lines 15 and 16 are connected to the sleeve 23. The connection port 10a of the supply line 10 and the connection port 18a of the discharge line 18 are configured to communicate with each other via a recess 23a formed on the outer peripheral surface. As a result, in the neutral position, the hydraulic chambers 6 and 7 of the power cylinder 2 are connected to each other through the supply and discharge lines 15 and 16, and the flow of hydraulic oil between the hydraulic chambers 6 and 7 is allowed. Will be. Further, the hydraulic oil supplied to the control valve 14 via the supply line 10 is returned to the reserve tank 17 via the discharge line 18.

When the steering wheel is operated to change the relative angle between the rotor 21 and the sleeve 23, for example, as shown in FIG.
Connection port 10a of the discharge line 18 communicates with the connection port 16a of the one supply / discharge line 16 through the recess 23a of the sleeve 23, and the connection port 18a of the discharge line 18 is connected to the sleeve 23.
Connection port 1 of the other supply / discharge line 15 via the recess 23a of
It is in a state of communicating with 5a.

In the above operating position, the supply line 10
Hydraulic oil is supplied from the power steering mechanism 3 to the right hydraulic chamber 7 of the power cylinder 2 through the control valve 14 and the supply / discharge line 16 of the power steering mechanism 3, and the left hydraulic chamber 6 is supplied.
The hydraulic oil inside is the above-mentioned supply / discharge line 15 and control valve 14.
Through the discharge line 18. As a result, the piston 8 and the steering rod 1 are urged to the left side in the figure, and a steering assist force is obtained.

When the steering wheel is operated in the opposite direction to the above example, the control valve 1 is fed from the supply line 10.
4 is supplied to the hydraulic chamber 6 on the left side of the power cylinder 2 via the supply / discharge line 15 and the hydraulic oil in the hydraulic chamber 7 on the right side is supplied to the supply / discharge line 16 and the control valve 14. It is led out to the discharge line 18 via. As a result, a steering assist force for urging the steering rod 1 to the right side in the figure is obtained.

When the amount of operation of the steering wheel changes and the amount of change in the relative angle between the rotor 21 and the sleeve 23 increases or decreases, the supply line 10 and the supply / discharge line 15 that communicate with each other via the recess 23a of the sleeve 23. , 16 to change the communication area with one of them, and the supply pressure of the hydraulic oil is adjusted. Further, in the same manner, the communication area between the discharge line 18 and the other of the supply / discharge lines 15 and 16 is changed to adjust the discharge resistance of the hydraulic oil. As a result, the steering assist force corresponding to the operating state of the steering wheel is obtained.

As shown in FIG. 1, a pair of open / close valves 26, 27 for opening / closing the supply / discharge lines 15, 16 at the same time are installed in parallel on the supply / discharge lines 15, 16, respectively.
Both of the on-off valves 26, 27 are normally open so that the two supply / discharge lines 15, 16 are electrically connected to the control valve 14, and the on-off valves 26, 27 are operated when the automatic steering mechanism 4 described later is operated. Is closed to prevent the hydraulic oil derived from the hydraulic chambers 6 and 7 of the power cylinder 2 from being extracted to the control valve 14.

The automatic steering mechanism 4 controls the power oil supply line 28 having one end connected to the switching valve 13 and the flow rate and supply path of the hydraulic oil introduced into the supply line 28 to control the power. A control valve 29 for automatic steering that controls the operating position of the cylinder 2, and this control valve 2
9 and the supply / discharge line 15 of the power steering mechanism 2,
Connection lines 30 and 31 for connecting the control valve 29 to the discharge line 18 of the power steering mechanism 3.
And a discharge line 32 connecting the

During the automatic steering operation, the switching valve 13 is driven to the left in the figure to introduce hydraulic oil from the switching valve 13 into the supply line 28, and the hydraulic oil is fed from the automatic steering control valve 29 to the above. Both connection lines 30, 3
The hydraulic oil introduced into the power cylinder 2 via either one of the first and second supply / discharge lines 15 and 16 and the hydraulic oil derived from the power cylinder 2 is supplied to the supply / discharge lines 15, 16.
16 and the other of the connecting lines 30 and 31 are discharged into the reserve tank 17 through the control valve 29 and the discharge lines 32 and 18.

Both connecting lines 30 of the automatic steering mechanism 4,
The pressure control means 33 for controlling the pressure of the hydraulic oil supplied through the supply line 28 and the control valve 29 for automatic steering and the relief passage 34 having a check valve are provided at 31. Then, during automatic steering operation, a part of the hydraulic oil supplied via the control valve 29 is led out from the relief passage 34 to the reserve tank 17 side, so that the maximum pressure of the hydraulic oil supplied to the power cylinder 2 becomes the above-mentioned. It is regulated by the pressure control means 33.

In the illustrated example, the relief passage 34 is connected to the control valve 29, and the working oil is discharged to the reserve tank 17 side through the control valve 29. However, the relief passage 34 is reserved. The structure may be such that the discharge line 18 communicating with the tank 17 is directly connected.

Further, in both the connecting lines 30 and 31,
A check valve 35 that blocks the flow of the hydraulic oil, which is derived from the power cylinder 2, into the control valve 29, and a bypass line 36 that bypasses the check valve 35.
And are respectively provided in the bypass line 36,
A check valve 37 that allows the working oil derived from the power cylinder 2 to flow into the control valve 29, and an oil filter 38 are provided. As a result, when the hydraulic oil derived from the power cylinder 2 is supplied to the control valve 29, the hydraulic oil always passes through the oil filter 38.

The control valve 29 for automatic steering is shown in FIG.
And as shown in FIG. 6, the connection port 2 of the supply line 28, both connection lines 30, 31 and the discharge line 32.
8a, 30a, 31a, 32a formed valve body 39, spool 40 slidably installed in the valve body 39, coil springs 41, 41 for biasing the spool 40 to a neutral position, It has proportional solenoids 42, 42 for slidingly displacing the spool 40. When the spool 40 is normally held in the neutral position, the connection ports 28a, 30a, 31a, 32a are closed by the spool 40 to supply hydraulic oil to the power cylinder 2 and discharge hydraulic oil to the reserve tank 17. Is being cut off.

Then, the proportional solenoid 42 operates in response to a control signal output from a controller described later,
As shown in FIG. 6, when the spool 40 slides to one side, one of the connection ports 30 a and 31 a of both the connection lines 30 and 31 is connected to the supply line 28 via the step portion 40 a formed on the spool 40. Of the power cylinder 2 while communicating with the connection port 28a of the exhaust line 32 while the other of the connection ports 30a and 31a communicates with the connection port 32a of the discharge line 32 through the communication hole 43 formed in the valve body 39. The hydraulic oil is supplied to and discharged from.

By reversing the sliding direction of the spool 40, the connection lines 30 and 31 communicating with the supply line 28 and the discharge line 32 are changed, and accordingly the flow of hydraulic oil to the power cylinder 2 is changed. Is reversed. Further, since the sliding amount of the spool 40 is controlled by the proportional solenoid 42, the communication area between the supply line 28 and one of the communication lines 30 and 31 is changed and the supply flow rate of the hydraulic oil to the power cylinder 2 is changed. It is configured to be adjusted.

In this way, the supply direction and flow rate of the operation of the power cylinder 2 with respect to the hydraulic chambers 6, 7 are adjusted to control the operating position of the power cylinder 2, that is, the displacement position of the piston 8. The automatic steering operation, such as traveling while maintaining a constant distance from the boundary line part, is performed. When the steering wheel is operated during the automatic steering operation, the steering force applied to the steering mechanism in response to the manual operation turns the steering force against the driving force of the automatic steering mechanism 4. It will be.

The switching valve 13 is selectively switched and controlled in accordance with a control signal output from the controller, so that the supply line 10 of the power steering mechanism 3 is brought into a communication state during the power steering operation and is automatically operated. The supply line 28 of the steering mechanism 4 is cut off,
During the automatic steering operation, the supply line 10 of the power steering mechanism 3 is cut off and the supply line 28 of the automatic steering mechanism 4 is opened.

Further, the pressure control means 33, as shown in FIGS. 7 and 8, has a connection port 34 of the relief passage 34.
a valve body 44 in which a and 34b are formed, a valve body 45 slidably installed in the valve body 44, and the upstream connection port 3 of the relief passage 34 by the valve body 45.
4a is a pressure control valve having a coil spring 46 for urging the valve element 45 in a direction to close the valve 4a, and a proportional solenoid 47 for adjusting the urging force by changing the rear end support position of the coil spring 46. ing.

As shown in FIG. 7, the pressure control means 33 normally discharges hydraulic oil to the reserve tank 17 side through the relief passage 34 when the valve body 45 closes the connection port 34a. It is configured to prevent being played. When the pressure of the hydraulic oil supplied to the power cylinder 2 side through the supply / discharge passages 30 and 31 increases, the valve body 45 is pressed by the hydraulic oil and the coil spring 46 is pressed, as shown in FIG. Retreat against the urging force of.

As a result, the hydraulic oil flows into the valve body 44 from the upstream connection port 34a of the relief passage 34 and flows out from the downstream connection port 34b of the relief passage 34 to the reserve tank 17 side. The maximum pressure of the hydraulic oil supplied to is adjusted. Further, in this embodiment, by adjusting the biasing force of the coil spring 46 by the proportional solenoid 47,
The supply pressure of the hydraulic oil regulated by the pressure control means 33 is controlled.

FIG. 9 shows a control unit for controlling the automatic steering mechanism 4. The control unit includes a control unit 48 having a microcomputer, a steering angle sensor 49 for detecting a steering angle of a steering wheel, a vehicle speed sensor 50 for detecting a vehicle speed, and an indicator sensor for detecting an operating state of a direction indicator. 51, and a distance sensor 52 for detecting a distance between a vehicle body and a boundary line portion of a traveling road including a white line
And a manual switch 53 for selecting the automatic steering operation.

When the manual switch 53 is in the ON state and there is a high possibility that the vehicle will deviate from the traveling line, a switching signal for switching the switching valve 13 to the automatic steering operation position and opening / closing of the power steering mechanism 3 are performed. A control signal for closing the valves 26, 27 and a control valve 29 and pressure control means 3 of the automatic steering mechanism 4 so as to keep the distance from the vehicle body to the boundary line portion constant.
Alarm signal 5 consisting of a control signal to activate 3 and a buzzer
A command signal for activating 4 is output from the control unit 48.

The control operation of the automatic steering operation executed by the control unit 48 will be described with reference to the flowchart shown in FIG. When the above control operation starts,
First, in step S1, it is determined whether the manual switch 53 is in the ON state. This determination result is NO
If it is, there is no need for automatic steering control, and therefore the process directly returns.

If YES is determined in step S1, the sensors 49 and 5 are set in step S2.
Current vehicle speed V0 based on the output signal of 0,52, after reading the distance L and the steering angle θh to the boundary line of the travel path, in step 3, by differentiating the steering angle theta h, the steering speed Calculate dθh.

Next, in step S4, it is determined based on the output signal of the indicator sensor 51 whether or not the turn indicator is in the OFF state. If the result of this determination is NO and it is confirmed that the turn signal indicator is in the operating state, it is clear that the driver does not want automatic steering operation. Cancel the driving control status. As a result, the power steering mechanism 3 is operated according to the operation of the steering wheel by the driver.
It becomes a normal driving state in which the assist power of is obtained.

If YES is determined in step S4, it is determined in step S5 whether or not the driving state of the vehicle is within the predetermined range based on the map set with the steering angle θh and the steering speed dθh as parameters. To determine. That is, it is determined whether or not the steering angle θh and the steering speed dθh are in a driving state equal to or greater than a preset threshold value. If YES is determined in the above step S5 and it is confirmed that the vehicle is in the driving state in the predetermined region, the driver may deviate from the traveling road for some reason even if the turn signal is not ON. Since it is considered clear that the intention to do so, the process proceeds to step S6, and the automatic steering operation is canceled.

If it is determined NO in step S5 and it is confirmed that the vehicle is not operating in the predetermined region, the distance L from the vehicle body to the boundary line of the traveling road is set in advance in step S7. It is determined whether it is smaller than the set first threshold value L1. If the result of this determination is YES, there is a high possibility that the vehicle will deviate from the traveling road. Therefore, in step S8, after outputting a control signal for turning on the alarm device 53, in step S9,
A second threshold value L in which the distance L from the vehicle body to the boundary line of the road is set to a value smaller than the first threshold value L1.
It is determined whether it is smaller than 2.

When YES is determined in the above step S9, the distance L from the vehicle body to the boundary portion is the second reference value L2.
If it is confirmed that the distance L is smaller than the above, a control signal for executing the automatic steering operation to secure the distance L is output to the automatic steering mechanism 4. That is, the switching valve 13 provided in the hydraulic oil supply line 10 is connected to the automatic steering mechanism 4
After switching to the side and closing the on-off valves 26 and 27 of the power steering mechanism 3 respectively, the proportional solenoid 42 of the control valve 29 is operated in accordance with the running condition of the vehicle to keep the distance L constant. The steering state of the vehicle is controlled so as to maintain the value.

If necessary, the pressure control means 33 is also provided.
By operating the proportional solenoid 47, the maximum pressure of the hydraulic oil supplied to the power cylinder 2 is adjusted to control the steering speed. If the determination result in step S6 or step S9 is NO, the process returns to step S1.

Since hydraulic oil is supplied to the power steering mechanism 3 and the automatic steering mechanism 4 by the hydraulic source composed of the common hydraulic pump 9 as described above, the power steering operation assists the steering force with a simple structure, and It is possible to appropriately perform the automatic steering operation in which the operating position of the power cylinder 2 is controlled so as to keep the steering angle constant according to the traveling situation.

Since the pressure control means 33 controls the pressure of the hydraulic oil supplied from the control valve 29 for automatic steering to the power cylinder 2 when the automatic steering mechanism 4 is operated, the power cylinder 2 is properly operated. To prevent the occurrence of a situation in which an excessive steering force is applied from the power cylinder 2 to the steering rod 1 during automatic steering operation, while being able to operate quickly by pressure and maintaining a good steering response. You can

That is, as shown in FIG. 11, the operating characteristic of the control valve 29 of the automatic steering mechanism 4 is set so that the supply pressure of the hydraulic oil sharply rises as the valve opening increases. The hydraulic oil discharged from the hydraulic pump 9 can be quickly supplied to the power cylinder 2 when the automatic steering mechanism 4 is activated. Also,
Since the maximum pressure of the hydraulic oil is regulated by the pressure control means 33, the control valve 29 is controlled as described above.
Despite the setting of the operating characteristic of No. 1, it is possible to suppress the maximum driving force of the power cylinder 2 and prevent an excessive steering force from being applied to the steering rod 1.

Therefore, as shown by the solid line in FIG.
As in the case where the supply pressure of the hydraulic oil is gradually increased in accordance with the increase in the valve opening, the steering responsiveness during the automatic steering operation is deteriorated, or as shown by the broken line in FIG. It is possible to reliably prevent the situation in which the pressure of the hydraulic oil supplied to the power cylinder 2 becomes excessive, as in the case of the configuration in which the hydraulic oil supply pressure is rapidly increased in accordance with the increase in the opening degree. can do.

Further, as described above, the pressure control means 33 is arranged on the downstream side of the control valve 29 of the automatic transmission mechanism 4 .
Because, compared with the case of disposed upstream of the control valve 29 of the pressure control means, for the pressure gain of the hydraulic fluid supplied to the pressure control means 33 can be set to a higher value, is rapidly operate the power cylinder 2 As a result, the steering response during automatic steering operation can be improved. Moreover, the pressure control means 3
Since the power cylinder 2 can be operated by the hydraulic oil whose pressure is appropriately controlled by 3, the operating pressure of the power cylinder 2 is reduced due to the decrease of the hydraulic oil supply pressure in the control valve 29. The fluctuation can be effectively prevented.

As shown in FIG. 13, a prada type, a piston type, a metal bellows type, a direct pressure type, a spring type or a spring type which stores the hydraulic oil discharged from the hydraulic pump 9 on the supply line 28 of the automatic transmission mechanism 4. The structure may be such that the pressure accumulating means 55 including a weight type accumulator or the like is provided. With this configuration, the high-pressure hydraulic oil stored in the pressure accumulating means 55 is supplied to the power cylinder 2 via the control valve 29 or the like immediately after the automatic steering mechanism 4 is operated. The steering response can be further improved.

Further, as shown in FIG. 14, on the supply line 10 of the power steering mechanism 3, a flow rate adjusting valve 56 for adjusting the flow rate of the hydraulic oil and a bypass line for bypassing the installation portion of the flow rate adjusting valve 56. 57 is provided, and the opening / closing valve 5 is connected to the bypass line 57.
The structure in which 8 is provided may be adopted. Then, during the power steering operation, the opening / closing valve 58 is closed to control the flow rate of the hydraulic oil supplied through the supply line 10 according to the discharge pressure of the hydraulic pump 9, and during the automatic steering operation, the opening / closing operation is performed. The valve 58 may be opened to stop the function of the flow rate adjusting valve 56.

The flow rate adjusting means comprising the flow rate adjusting valve 56 is, for example, as shown in FIG. 15, a pump port 59 communicating with the discharge port of the hydraulic pump 9, a suction port 60 communicating with the suction port of the hydraulic pump 9, and the above. A valve body 6 in which a connection port 61 communicating with the supply line 10 is formed
2, a valve body 63 slidably installed in the valve body 62, and a pressure adjusting spring 6 provided in the valve body 63.
4 and a flow rate adjusting spring 65 for urging the valve element 63 toward the tip end side thereof.

At normal times when the discharge pressure of the hydraulic pump 9 is low, the pump port 59 and the connection port 61 of the supply line 10 communicate with each other through the metering orifice 66 formed in the valve body 63, and the hydraulic pump 9 is connected. All of the hydraulic oil discharged from is supplied to the downstream side of the supply line 10. Then, when the discharge pressure of the hydraulic pump 9 becomes high, as shown in FIG.
The valve element 63 moves backward against the urging force of the hydraulic pump 9 so that the pump port 59 and the suction port 60 communicate with each other, and a part of the hydraulic oil discharged from the hydraulic pump 9 is returned to the suction port of the hydraulic pump 9. It will be.

As a result, during the power steering operation, as shown in FIG. 17, when the engine speed rises to a constant value and the flow rate adjusting valve 56 becomes the operating state, the operation of passing through the flow rate adjusting valve 56. The oil flow rate is constant. Therefore, it is possible to prevent the steering assist force from changing due to the influence of the engine speed that changes according to the running state of the vehicle, and to perform a stable steering operation.

During the automatic steering operation, the opening / closing valve 58 is closed to stop the function of the flow rate adjusting valve 56, so that the flow rate of the hydraulic oil supplied to the control valve 29 of the automatic transmission mechanism 4 is sufficiently increased. Therefore, the power cylinder 2 can be quickly operated to improve the steering response.

Incidentally, instead of the structure in which the flow rate of the hydraulic oil is adjusted according to the engine speed as described above, the hydraulic pump 9 to the control valve 14 of the power steering mechanism 3 are changed according to the traveling speed of the vehicle. The flow rate of the hydraulic oil supplied to the power cylinder 2 via the may be adjusted.

Further, in the above embodiment, the pressure control means 33 is provided between the control valve 29 of the automatic steering mechanism 4 and the power cylinder 2, but the hydraulic oil located upstream of the control valve 29 is controlled. A structure in which pressure control means is provided on the supply line 28 may be adopted. Further, as shown in FIG. 18, the pressure control means 67 composed of a relief valve may be provided on the hydraulic oil discharge line 18 communicating with the supply line 28. With this configuration,
The pressure of the hydraulic oil supplied to both hydraulic chambers 6 and 7 of the power cylinder 2 can be controlled by a single pressure control means, and the structure of the hydraulic control circuit can be simplified.

Further, as shown in FIG. 18, the supply / discharge lines 15, 16 of the power steering mechanism 3 are replaced by the open / close valves 26, 27 provided on the supply / discharge lines 15, 16 of the power steering mechanism 3, as shown in FIG. 16 and the switching valve 6 at the connecting portion between the supply / discharge lines 30 and 31 of the automatic steering mechanism 4.
8 and 69 may be provided, and the supply / discharge line communicating with the power cylinder 2 may be changed by switching the switching valves 68 and 69 between the power steering operation and the automatic steering operation. Good.

Further, it is also possible to adopt a structure provided with pressure changing means such as a variable machine for changing the reduction ratio of the driving force transmitted from the engine to the hydraulic pump 9. Then, by changing the rotational speed of the hydraulic pump 9 depending on the operation of the power steering mechanism 3 and the operation of the automatic steering mechanism 4, an appropriate steering assist force is applied during the power steering operation, During the steering operation, the supply pressure of the hydraulic oil is adjusted so that the hydraulic oil having an appropriate pressure can be quickly supplied to the power cylinder 2 while preventing the hydraulic oil having an excessive pressure from being supplied to the power cylinder 2. It may be changed by the pressure changing means.

[0066] Further, in the above embodiment uses the rotor Riva lube as control valve 14 of the power steering mechanism 3 may be a conventional known control valve, such as a spool valve type instead. Further, the control valve 29 of the automatic steering mechanism 4 configured to be driven by the proportional solenoid 42 may be replaced with a control valve or the like driven by pilot hydraulic pressure.

[0067]

As described above, according to the present invention, the hydraulic oil is supplied to the power steering mechanism and the automatic steering mechanism by the common hydraulic power source, and the automatic steering mechanism is operated when the automatic steering mechanism is operated. Since the pressure of the hydraulic oil supplied from the control valve to the power cylinder is controlled by the pressure control means, the pressure of the hydraulic oil supplied from the control valve for automatic steering can be increased quickly. By setting the characteristics, it is possible to quickly operate the power cylinder at an appropriate pressure during automatic steering operation, and it is possible to effectively improve steering response.

Since the pressure of the hydraulic oil supplied from the control valve for automatic steering to the power cylinder is regulated by the pressure control means, the pressure of the hydraulic oil supplied to the power cylinder becomes excessive. Thus, it is possible to prevent a situation in which the manual steering function is impaired during the automatic steering operation and the sealing performance of the power cylinder is impaired . Also, a control valve of the power steering mechanism, with a control valve of the automatic steering mechanism provided in parallel, because this is disposed a pressure control means on the downstream side of the control valve of the automatic steering mechanism, the pressure control during automatic steering operation by rapidly supplying high pressure hydraulic fluid to the installation portion of the unit, promptly actuates the power cylinder in comparison with the case of disposing the said pressure control means upstream of the control valve, the steering during automatic steering operation There is an advantage that the responsiveness can be improved.

Further, according to the structure in which the hydraulic circuit of the automatic speed change mechanism is provided with the pressure accumulating means for accumulating the hydraulic oil discharged from the hydraulic pressure source, the high pressure hydraulic oil accumulated in the pressure accumulating means is provided immediately after the operation of the automatic steering mechanism. Can be quickly supplied to the power cylinder, so that the driving force of the hydraulic power source can be effectively used to further improve the steering response during the automatic steering operation.

Further, a flow rate adjusting means for adjusting the supply flow rate of the hydraulic oil discharged from the hydraulic pressure source in accordance with the operating state of the power steering mechanism is provided, and at the time of automatic steering operation, the hydraulic oil by the flow rate adjusting means is adjusted. When configured to regulate the flow rate adjusting action, during power steering operation, by adjusting the flow rate of the hydraulic oil supplied by the flow rate adjusting means, it is possible to obtain a steering assist force suitable for the operating state, At the time of automatic steering operation, by stopping the function of the flow rate adjusting means,
There is an advantage that the hydraulic fluid discharged from the hydraulic pressure source can be quickly supplied to the power cylinder to improve the steering response.

Further, in the case where the above-mentioned flow rate adjusting means controls the supply flow rate of the hydraulic oil according to the engine speed during the power steering operation, the engine speed fluctuates according to the running state of the vehicle. Since the supply flow rate of the hydraulic oil can be maintained constant without being affected, it is possible to prevent the steering assist force from changing and perform a stable steering operation.

Further, according to the structure provided with the pressure changing means such as a variable speed reducer for changing the reduction ratio of the driving force transmitted from the engine to the hydraulic pump, the pressure changing means can be used when the power steering mechanism is operated. By changing the pressure of the hydraulic oil supplied from the hydraulic source such as the hydraulic pump at the time of operating the automatic steering mechanism, an appropriate steering assist force can be applied during the power steering operation, and There is an advantage that the hydraulic oil can be quickly supplied to the power cylinder while preventing the hydraulic oil having an excessive pressure from being supplied to the power cylinder during the steering operation.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram showing an embodiment of a steering control device for an automobile according to the present invention.

FIG. 2 is a vertical cross-sectional view showing a specific structure of a control valve for power steering.

FIG. 3 is a cross-sectional view of the control valve for power steering.

FIG. 4 is a transverse cross-sectional view showing an operating state of the control valve for power steering.

FIG. 5 is a sectional view showing a specific structure of a control valve for automatic steering.

FIG. 6 is a cross-sectional view showing an operating state of the control valve for automatic steering.

FIG. 7 is a cross-sectional view showing a specific structure of pressure control means.

FIG. 8 is a cross-sectional view showing an operating state of the pressure control means.

FIG. 9 is a block diagram showing a configuration of a control unit of a hydraulic circuit.

FIG. 10 is a flowchart showing a control operation of the steering control device.

FIG. 11 is a graph showing a relationship between operating characteristics of a control valve for automatic steering and supply hydraulic pressure.

FIG. 12 is a graph showing operating characteristics of a control valve for automatic steering according to a conventional example.

FIG. 13 is a hydraulic circuit diagram showing another embodiment of the vehicle steering control device according to the present invention.

FIG. 14 is a hydraulic circuit diagram showing still another embodiment of the steering control device.

FIG. 15 is a cross-sectional view showing a specific structure of flow rate adjusting means provided in the hydraulic circuit.

FIG. 16 is a sectional view showing an operating state of the flow rate adjusting means.

FIG. 17 is a graph showing operating characteristics of the flow rate adjusting means.

FIG. 18 is a hydraulic circuit diagram showing still another embodiment of the steering control device.

[Explanation of symbols]

1 Steering rod 2 power cylinder 3 Power steering mechanism 4 Automatic steering mechanism 9 Hydraulic pump (hydraulic power source) 14 Control valve for power steering 29 Control valve for automatic steering 33,67 Pressure control means 55 Accumulator 56 Flow control means

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-5-238407 (JP, A) JP-A-5-50932 (JP, A) JP-A-7-81603 (JP, A) Actual development Sho-59- 37606 (JP, U) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B62D 5/07

Claims (5)

(57) [Claims] 1. A power steering mechanism for assisting an operating force of a steering wheel, an automatic steering mechanism for automatically steering according to a running condition of a vehicle, and hydraulic oil supplied from the power steering mechanism or the automatic steering mechanism. A steering device for an automobile, comprising: a power cylinder for driving a steering shaft by means of: a common hydraulic pressure source for supplying hydraulic oil to the power steering mechanism and the automatic steering mechanism; and the hydraulic pressure source when operating the automatic steering mechanism. And a pressure control means for controlling the pressure of the hydraulic oil supplied from the power steering to the power cylinder , and the power steering.
Control valve for power steering provided in the mechanism
And a control valve for automatic steering provided in the automatic steering mechanism
And are installed in parallel and the control bar for this automatic steering is
Of the hydraulic oil supplied to the power cylinder on the downstream side of the lube.
Pressure control hand that regulates the pressure below a preset reference value
A steering control device for an automobile, characterized in that a step is provided . 2. The automatic steering mechanism is provided with pressure accumulating means for accumulating hydraulic oil supplied from a hydraulic pressure source, and the hydraulic oil is supplied from the pressure accumulating means to the power cylinder during automatic steering operation. Item 1. A steering control device for an automobile according to item 1. 3. A flow rate adjusting means for adjusting the supply flow rate of the hydraulic oil discharged from the hydraulic pressure source in accordance with the operating characteristics of the power steering mechanism, and the flow rate of the hydraulic oil by the flow rate adjusting means during automatic steering operation. The steering control device for an automobile according to claim 1, wherein the steering control device is configured to regulate an adjusting action. 4. A steering control device for an automobile according to claim 3, further comprising flow rate adjusting means for adjusting the flow rate of the hydraulic oil supplied from the hydraulic source according to the engine speed. 5. A power steering mechanism for assisting an operating force of a steering wheel, an automatic steering mechanism for automatically steering according to a running condition of a vehicle, and hydraulic oil supplied from the power steering mechanism or the automatic steering mechanism. A steering device for an automobile, comprising: a power cylinder for driving a steering shaft by means of a vehicle; a common hydraulic pressure source for supplying hydraulic oil to the steering mechanism and the automatic steering mechanism; A steering control device for an automobile, comprising pressure changing means for changing the pressure of oil between when the power steering mechanism is operated and when the automatic steering mechanism is operated.