JPS6310002B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an integrated control device for a suspension device and a steering device with variable characteristics.

A vehicle's suspension device has the role of supporting the weight of the vehicle and cushioning road surface irregularities, and it not only improves ride comfort but also prevents pitching, rolling, and
Furthermore, it has a significant effect on stability and responsiveness during turning. Therefore, by appropriately changing the suspension characteristics of the front and rear wheels of the vehicle, the dynamic characteristics can be varied in various ways. For example, in Utility Model Application No. 56-147107, roll speed is detected using a steering sensor that detects changes in steering angle and a vehicle speed sensor, and the roll speed is controlled to increase (harden) the damping force of all wheel shock absorbers. A device has been disclosed that prevents the speed from exceeding a predetermined value and improves both maneuverability and ride comfort.

On the other hand, in terms of steering devices for steering vehicles, power steering devices have become widely used, especially from the viewpoint of ease of steering, but these steering devices also have an impact on the running stability and steering response of the vehicle. Due to this significant impact, various improvements have been proposed in the past. For example, Japanese Patent Application Laid-Open No. 55-55059 discloses that the number of revolutions of an oil pump that supplies hydraulic pressure to a hydraulically operated power steering device is controlled according to changes in vehicle speed, the axle load of the steered wheels, or steering resistance. A control device has been proposed that stabilizes steering by supplying pressurized oil.

These conventional devices have individually improved the suspension device or steering device,
Although this method has achieved a certain degree of effectiveness, there are limits to its effectiveness when these suspension devices and steering devices are individually controlled. In particular, there are individual differences in driver preferences regarding vehicle dynamic characteristics such as steering response and ride comfort, which vary widely from person to person, so these conventional methods do not always meet the driver's needs. It wasn't something. For example, when a driver wants to switch from a characteristic emphasizing ride comfort to a characteristic emphasizing sportiness according to the driver's preference, conventional devices are not satisfactory.

Therefore, an object of the present invention is to change the characteristics of the steering device in accordance with the variable control of the suspension characteristics of the suspension device, so that the dynamic characteristics can be changed over a wide range to fully satisfy the driver's preferences. An object of the present invention is to provide a comprehensive control device for a suspension device and a steering device.

The present invention is an integrated control device for a suspension device and a steering device, and includes a suspension device for all wheels, a power steering device including a steering force assist mechanism, and a damping force and a damping force of the suspension device for all wheels. a first control means that performs control to change at least one of the spring constants; a second control means that performs control to change the assist force characteristics of the power steering device;
A first control signal that increases at least one of the damping force and the spring constant of the suspension device for all wheels is output to the first control means, and the power steering device is controlled in accordance with the output of the first control signal. a controller that outputs a second control signal to the second control means to increase the assist force by a predetermined amount compared to the assist force before the first control signal is output; and a change in the damping force or spring constant of the suspension device. The assist force of the power steering device is changed in synchronization with the

According to the present invention, it is possible to switch the damping force or spring constant of the suspension device between a low state and a high state, that is, the suspension characteristics of the suspension device can be switched from soft to hard. In some cases, dynamic characteristics that emphasize ride comfort can be obtained, and when at least one of the suspension device's damping force or spring constant is increased, the assist force of the power steering device is controlled to be increased, so a steering wheel with a large yaw rate can be obtained. The result is an emphasis on driving characteristics with a sharp, sporty feel. That is, according to the present invention,
It is possible to change the dynamic characteristics over a wide range, and it is possible to respond to the driver's preferences.

For example, a gas spring device is used in the suspension device, and a control gas chamber is connected to the gas chamber of the gas spring device via a solenoid valve, and the effective volume of the gas chamber is changed by opening and closing the solenoid valve to control the gas spring. All you have to do is change the characteristics of In addition, an oleo damper in which the piston is provided with a variable diameter orifice may be used, or a means for varying the volume of the gas chamber of the gas spring and a means for varying the diameter of the piston orifice of the oleo damper may be combined. .
Furthermore, any means may be used as long as the suspension characteristics can be varied between hard and soft. As a means for making the characteristics of the steering device variable, a known method that changes the power assist force of the power steering device may be used, such as a method that changes the rotation speed of the hydraulic pump of the power steering device, or a method that changes the rotation speed of the hydraulic pump of the power steering device, or Any method may be used, such as a method that changes the amount of bypass.

Embodiments of the present invention will be described below with reference to the drawings.

Referring to FIGS. 1 and 2, the handle 10
is connected via a steering shaft 12 to a pinion shaft 16 having a steering pinion 14 . The pinion 14 meshes with a rack 20 on the steering rack shaft 18.
8 moves left and right according to the rotation of the pinion 14, and connects the front wheels 26, 28 via the knuckle arms 22, 24.
The steering force is transmitted to the A piston 32a of a power cylinder 32 is fixed to the rack shaft 18,
A hydraulic chamber 32b defined in this piston 32a,
Hydraulic passages 40 and 42 communicating with 32c are connected to an oil pump 36 via a control valve 31. The control valve 31 has conventionally been commonly used in this type of power steering device, and controls the discharge piping of the oil pump 36, that is, the hydraulic pressure supply passage 44 and the hydraulic pressure return passage 38, respectively, depending on the steering direction. aisle 4
Switch the hydraulic system to connect to 0 and 42 or 42 and 40. For example, rack shaft 18
When the vehicle is steered to move rightward in the figure, the hydraulic supply passage 44 is connected to the hydraulic passage 42, and the hydraulic return passage 38 is connected to the hydraulic passage 40, respectively. As a result, the hydraulic pressure within the power cylinder 32 assists the rightward movement of the rack shaft 18. Further, when the steering shaft 12 is not rotating, the control valve 31 allows the hydraulic pressure supply passage 44 and the hydraulic pressure return passage 38 to communicate directly, and does not send pressure oil to the power cylinder 32.

The oil pump 36 is directly driven by the engine 34 via a belt, and a solenoid valve 46 as a flow rate regulating valve is interposed in a hydraulic pressure supply passage 44 of the oil pump 36. This solenoid valve 46 includes a valve body 46 that is formed to be slidable in the vertical direction in the figure within the casing 46a.
b and a spring 4 that urges the valve body 46b upward in the figure.
6c, and a flow rate control solenoid 46d, and the casing 46a includes first and second boats 46e, 46f connected to the hydraulic supply passage 44 and a third port 46g connected to the hydraulic return passage 38.

When the flow rate control solenoid 46d is demagnetized, the valve body 46b is pulled upward in the figure by the spring 46c. Therefore, the third port 46g, which is closed by the valve body 46b, partially communicates with the first port 46e.
Since the flow returns to the hydraulic return passage 38 through the third port 46g, the flow rate exiting from the second port 46f decreases. On the other hand, when the flow rate solenoid 46d is excited, the valve body 46b is pushed down in the figure against the biasing force of the spring 46c. Therefore,
The third port 46g is gradually closed according to the amount of power supplied to the solenoid 46d, and the annular groove 46h carved around the valve body 46b is aligned with the first and second ports 46e and 46f. , these first and second ports 46e and 46f are communicated with each other (as shown in FIG. 2).

That is, as the amount of power supplied to the flow rate control solenoid 46d increases, most of the discharge amount of the oil pump 36 flows to the control valve 31, the steering assist force increases, and the amount of power supplied to the flow rate control solenoid 46d decreases. As it becomes smaller (in the demagnetizing direction), a portion of the discharge amount of the oil pump 36 is bypassed by the solenoid valve 46, so the flow rate to the control valve 31 decreases and the steering assist force becomes smaller.

A suspension device 60 is provided associated with the front wheels 26, 28 and the rear wheels 56, 58. This suspension device consists of a spring 62 and an oleo damper 6.
The damper 64 is provided with a shock absorber 66 consisting of a shock absorber 64, and an air spring 68 is formed around the damper 64 by a diaphragm made of a suitable elastic material. The orifice provided in the piston of the shock absorber 66 has a variable diameter, and in order to change the diameter, a plunger driven by a solenoid 69 is provided in the piston rod 67. When the solenoid 69 is energized, the plunger is driven by a solenoid 69. It is configured to rotate to reduce the diameter of the orifice and increase the damping force to harden the suspension characteristics of the suspension device. Furthermore, the air spring 68 is connected to a control air chamber 72 through an air pipe 70, and the state of communication between the air spring 68 and the control chamber 72 is controlled by the operation of a solenoid valve 74 provided at the entrance of this chamber 72. Ru. In this example, when the solenoid 74a of the solenoid valve 74 is energized, communication is cut off. air spring 6
When the communication between 8 and the control room 72 is cut off,
Since the effective volume of the air chamber decreases, the spring constant of the air spring increases, and the suspension characteristics of the suspension device become harder. Thus, the suspension characteristics of the suspension system can be controlled by operating the solenoids 69, 74a in response to signals from the controller 50.

As described above, the controller 50 receives the vehicle speed signal as an input, and the control signal given from the controller 50 to the solenoid valve 46 changes depending on the vehicle speed. That is, when the vehicle speed is low, the solenoid valve 46 is controlled so that the amount of pressure oil supplied from the pump 36 to the control valve 31 decreases as the vehicle speed increases. When the manual switch 54 is operated, the level of the signal given from the controller 50 to the solenoid valve 46 is increased, and the annular groove 46h of the valve body 46b and the first
Also, the amount of alignment with the second ports 46e and 46f increases, and the assist force is strengthened as a whole. At the same time, a signal is given from the controller 50 to the solenoids 69, 74a of the suspension device, and the characteristics of the front and rear wheel suspension devices become hard.

Referring to FIG. 3, one example of a control circuit of the controller 50 is shown.
is equipped with an fv converter 80, an adder circuit 82, a triangular wave generating circuit 84, a comparator 86, and an NPN type transistor 88. A pulse signal representing the vehicle speed from the vehicle speed sensor 52 is input to an fv converter 80, converted to a voltage signal, and input to the negative side of a comparator 86. The positive side of the comparator 86 is connected to the triangular wave generating circuit 84 and one terminal of the manual switch 54, and is also grounded via a resistor R1. The other terminal of the manual switch 54 is connected to a power terminal 90 from the power source 51. This constitutes an adder circuit 82, and when the manual switch 54 is open, the triangular wave is input to the comparator 86 at a normal level as shown by line a in FIG.
When is closed, the voltage signal from the power supply terminal 90 is added, and as shown by line b, the triangular wave is translated to a higher level side by the added voltage signal and is input to the comparator 86. The comparator 86 is shown in FIG.
The triangular waves shown by lines a and b are compared with the vehicle speed signal shown by line c, and when the triangular wave is large, a high level pulse signal is generated, and when the triangular wave is small, a low level pulse signal is generated. In this case, when the manual switch 54 is open, the triangular wave shown by line a and the vehicle speed signal shown by line c are compared, and the output has a relatively small pulse width as shown in FIG. 4b. When manual switch 54 is closed, the signals shown by lines b and c are compared, and the pulse width of the output is relatively large, as shown in FIG. 4c. The output signal from this comparator is input to the base of NPN type transistor 88. The collector of the transistor 88 is connected to the power supply terminal 92, and the emitter is connected to the solenoid 46d of the control valve 46.
When a high level signal is input to the base, the solenoid 46d becomes conductive and the solenoid 46d is energized.
Therefore, when the manual switch 54 is open, the pulse width of the output signal of the comparator 86 is small, so the amount of electric power supplied to the solenoid 46d is small, so that the amount of downward displacement of the valve body 46b in FIG. 2 is small. Therefore, the amount of pressure oil returned is large, and the assist force of the power steering device is relatively small. In this case, the relationship between the oil pressure generated in the power cylinder 32 and the steering force required by the driver, that is, the steering torque, has a characteristic as shown by curve a in FIG.
The steering wheel torque for obtaining a predetermined oil pressure P, that is, an assist force, is relatively large. Further, when the manual switch 54 is closed, the pulse width of the output signal of the comparator 86 increases, the amount of electric power to the solenoid 46d increases, the amount of return pressure oil decreases, and the assist force increases.
In this case, the characteristic is as shown by curve b in FIG. 5, and the steering wheel torque for obtaining the predetermined oil pressure P, that is, the assist force, becomes small. Further, the relationship between the steering wheel torque and the road resistance is as shown in FIG. That is, when the assist force is small, a relatively large steering torque is required as shown by curve a, and when the assist force is large, the steering torque becomes relatively small as shown by curve b.
Note that line c shows the case when a manual steering device is used, and in this case, as the road resistance increases, the steering torque increases proportionally, but in the case of curves a and b using a power steering device, the road surface resistance increases. Even if increases, the steering torque does not increase that much. Referring again to FIG. 3, the manual switch 54 is connected to each suspension device 60.
It is connected to a solenoid 69 that changes the damping force of the shock absorber 66 and a solenoid 74a that changes the spring constant of the air spring 68. When the manual switch 54 is open, each solenoid 69
The solenoid 74a is de-energized, and the damping force of the shock absorber 66 and the spring constant of the air spring 68 are small. That is, the suspension characteristics of the suspension device are maintained softly for all wheels. When the manual switch 54 is closed, the solenoid 69 is energized, the plunger of the shock absorber 66 is rotated, the diameter of the orifice is reduced, the damping force is increased, and the solenoid 74 is energized and the gap between the air spring 68 and the control chamber 72 is increased. communication is cut off and the spring constant increases. That is, the suspension characteristics of the suspension device 60 become hard for all wheels. Therefore, by switching the manual switch 54 from open to closed, the suspension characteristics of the suspension device 60 can be changed from soft to hard, and the assist force of the power assist device 30 can be changed from small to large in accordance with the change. It can be changed. By performing the above-mentioned control while keeping the vehicle speed substantially constant, motion characteristics as shown by lines a and b in FIG. 7 can be obtained.

In FIG. 7, lines c and d show the case when a manual steering device is used, line c shows the case when the suspension characteristics are set to soft, and line d shows the case when the suspension characteristics are set to hard. In this case, the yaw rate increases almost in proportion to the increase in steering force, and a larger steering force is required when the suspension device has soft characteristics. Lines a, b, e, and f are for the case where a power steering device is used. In this case, the steering force can be kept lower than when a manual steering device is used for steering operations at the same yaw rate. Lines e and f indicate the case where control is performed opposite to this example, that is, the assist force of the steering device is controlled to be reduced in response to changing the suspension characteristics of the suspension device 60 from soft to hard. This is the case.
With this kind of control, the steering force hardly changes even if the manual switch 54 is switched, but by performing the control in this example, a large change appears in the steering force, and when the switch is closed, the steering wheel operation becomes light. It can emphasize the sportiness more than anything else.

FIG. 8 shows another embodiment, in which an engine 3 is used as the power source for the oil pump 36.
4 is replaced by a motor 37. The motor 37 has a rotational speed corresponding to the amount of electric power supplied from the controller 50, and the oil pump 36 discharges an amount of oil according to the rotational speed. Therefore, as shown in FIG. 9, the amount of power of the motor 37 can be controlled using a controller similar to that used to control the solenoid 46d in the previous example, and the control valve 46 is not necessary. When the manual switch 54 is open, the amount of electric power to the motor 37 decreases, and the curve a in FIG.
As shown, the discharge flow rate of the pump 36 is small, and the assist force is relatively small. Furthermore, when the manual switch 54 is closed, as shown by curve b, the pulse width of the output signal of the comparator 86 increases and the amount of electric power to the motor 37 increases, as shown by curve b.
As the discharge flow rate increases, the assist force also increases.
Note that as the vehicle speed increases, the level of the voltage signal of the f-v converter 80 increases and the pulse width of the output signal of the comparator 86 decreases, so the amount of electric power to the motor 37 decreases, and the discharge flow rate and assist force of the pump 36 also decrease. Decrease.

Therefore, the same results as in the previous example can be obtained in this example as well.

[Brief explanation of the drawing]

FIG. 1 is an overall perspective view of a suspension device and a steering device according to an embodiment of the present invention, FIG. 2 is a control circuit diagram of the device shown in FIG. 1, and FIG. 3 is used for controlling the example of FIG. 1. Fig. 4 is a graph showing the relationship between voltage and time.
Figure 5 is a graph showing the relationship between power cylinder oil pressure and steering wheel torque, Figure 6 is a graph showing the relationship between steering wheel torque and road resistance, Figure 7 is a graph showing the relationship between steering force and yaw rate, and Figure 6 is a graph showing the relationship between steering force and yaw rate. 8 is a control circuit of another embodiment, FIG. 9 is a circuit diagram of a controller used in the embodiment of FIG. 8, and FIG. 10 is a graph showing the relationship between oil pump flow rate and vehicle speed. Explanation of symbols, 10...Handle, 18...Rack shaft, 30...Power assist device, 36...Oil pump, 50...Controller, 54...Manual switch, 60...Suspension device, 66
...Shock absorber, 72...Controlled air chamber,
80...Gear mechanism.

Claims (1)

[Claims] 1. A suspension device for each wheel, a power steering device equipped with a steering force assist mechanism,
a first control means that performs control to change at least one of a damping force and a spring constant of the suspension device for all wheels; a second control device that performs control to change an assist force characteristic of the power steering device; Outputting a first control signal to the first control means to increase at least one of the damping force and the spring constant of the suspension device for all wheels, and assisting the power steering device in accordance with the output of the first control signal. The second control signal increases the assist force by a predetermined amount compared to the assist force before the first control signal is output.
Comprehensive control of a suspension device and a steering device, characterized in that the controller outputs output to a control means and changes the assist force of a power steering device in synchronization with changes in the damping force or spring constant of the suspension device. Device.