JPS635283B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a suspension in which at least one of damper damping characteristics or spring characteristics (hereinafter referred to as suspension characteristics) is variable, and a power system in which steering characteristics (for example, steering force characteristics relative to front wheel steering angle) are variable. The present invention relates to a comprehensive suspension and steering control device that controls steering characteristics in accordance with the control of suspension characteristics in a steering device. BACKGROUND ART In automobile suspensions, systems have been proposed in which the damping force of a damper is controlled depending on the situation. For example, as shown in Japanese Utility Model Application No. 55-109008, a vehicle is known in which the damping force is changed depending on the vehicle speed so as to always obtain favorable handling characteristics. Suspensions consist of a combination of dampers and springs, and it is also possible to obtain similar handling characteristics by changing the spring characteristics. These systems strengthen understeer characteristics at high speeds to improve straight-line stability, and weaken understeer characteristics to increase turning performance at low speeds, thereby consistently providing favorable handling characteristics in response to changes in vehicle speed. Changing the understeer characteristics changes the steering characteristics (steering sensation)
changes. In other words, when the understeer characteristic is strengthened, the steering force increases, making the steering heavier, and the response during steering tends to be slower. When the understeer characteristic is weakened, the steering force decreases, the steering becomes lighter, and the response when steering becomes slower. The tendency for responsiveness to become sharper is strengthened. Moreover, the steering performance can also be changed by changing the steering characteristics. For example, in power steering, by changing the steering assist force (assist force), and in manual steering, by changing the ratio between the steering wheel steering angle and the front wheel turning angle (hereinafter referred to as steering reduction ratio), etc. The steering characteristics can be changed to change the handling characteristics. In other words, if you reduce the assist force with power steering, or if you increase the steering reduction ratio with manual steering, the stability when driving straight will increase and the steering feel will become dull; conversely, if you reduce the assist force with power steering, When the ratio is increased, or when the ratio is decreased using manual steering, it can be said that the response during steering is sharp and the steering feeling is sharp. As an example of changing the steering characteristics, for example, as shown in Japanese Patent Application Laid-open No. 55-55059, the steering force is changed depending on the vehicle speed, and the steering is made heavier at high speeds to increase straight-line stability, and the steering is made lighter at low speeds. There are known types of wheels that improve turning performance. As mentioned above, in the past, suspension characteristics or steering characteristics were controlled separately to increase straight-line stability during high-speed driving, where lane changes or relatively gentle curves were mostly involved, while Turning performance is increased during low-speed driving where there is a lot of cornering. By the way, changes in steering characteristics caused by changes in suspension characteristics can be expressed as changes in the sharpness of response and magnitude of steering force, and similarly, changes in steering characteristics caused by changes in steering characteristics can be expressed as changes in the sharpness of response and the magnitude of steering force. It can be expressed as a change in the sharpness of response and the magnitude of steering force. In other words, changes in handling characteristics appear as the same phenomenon. Considering this, if the changes in the suspension characteristics and the steering characteristics are controlled accordingly, it is possible to promote the above-mentioned steering characteristics and make them even larger, or cancel them out and reduce the changes. It can be said. In view of the above circumstances, the present invention has been developed to improve the understeer characteristics by changing the suspension characteristics.
In conjunction with this change, control is performed to change the steering characteristics to reduce the assist force of the power steering, and when the suspension characteristics are changed to weaken the understeer characteristics, the assist force of the power steering is An object of the present invention is to provide a comprehensive suspension and steering control device that performs control to change steering characteristics so as to increase the steering characteristics. The integrated suspension and steering control device according to the present invention includes a suspension unit that suspends a vehicle body on each of the front, rear, left and right wheels, a power steering device that steers a steerable wheel among the wheels, and a damping system for the suspension unit. A first step that variably controls the damping force ratio of the front wheels to the rear wheels or the spring constant ratio of the front wheels to the rear wheels by controlling at least one of the force and the spring constant;
a control means, a second control means for variably controlling the assist force of the power steering device, a first control signal for increasing at least one of the damping force ratio or the spring constant ratio, and outputting the first control signal to the first control means; outputting a second control signal to the second control means to reduce the assist force in accordance with the output of the first control means, and a third control signal to reduce at least one of the damping force ratio and the spring constant ratio. the damping force ratio or spring constant of the suspension unit; The present invention is characterized in that the assist force of the power steering device is changed in synchronization with the change in the ratio. According to the present invention, the steering characteristic can be changed in response to a change in the suspension characteristic, that is, in synchronization with the change in the suspension characteristic, simultaneously with this change, so as to promote a change in the steering characteristic caused by this change. Therefore, changes in the responsiveness and steering force due to changes in the suspension characteristics can more clearly appear as changes in the handling characteristics due to changes in the steering characteristics. Specifically, the suspension characteristics can be controlled by the driver using a manual switch, etc.
Or, in cases where the understeer characteristic can be automatically switched to strong or weak depending on the driving condition (for example, steering angle, vehicle speed, load, etc.), when the understeer is strong, the steering characteristic caused by this is changed. By further enhancing the steering characteristics, that is, by reducing the assist force of the power steering, the steering force is further increased, and the characteristics of good stability and low responsiveness are emphasized. Conversely, when understeer is weak, the power steering assist force is increased to improve steering characteristics, and the steering force is further reduced, emphasizing the characteristics of good responsiveness and low stability. By controlling the steering characteristics according to the suspension characteristics as described above, when the suspension characteristics are selected by manual switch operation, the steering characteristics can be adjusted according to the driver's will, such that the steering is heavy but has excellent straight-line stability. Alternatively, it is possible to select a steering characteristic that is light and has excellent responsiveness and turning performance. On the other hand, in the case of automatic control, the suspension characteristics are automatically changed depending on the driving condition of the car. Taking the steering angle as an example of the driving condition, when the steering angle is small, that is, the car is traveling straight or close to straight. During driving, the suspension characteristics have strong understeer to increase straight-line stability, but at the same time, the steering characteristics further increase straight-line stability by reducing the assist force of the power steering.
When the steering angle is large, that is, during cornering or other turning conditions, the suspension characteristics have little understeer to improve turning performance, but at the same time, turning performance can be further improved by increasing the assist force of the power steering. . Afterwards,
It is possible to create a so-called sporty car, which has excellent stability when driving straight, and responsiveness and maneuverability when turning. The characteristics described above can be summarized as shown in the following table.

[Table] Examples of the present invention will be described in detail below with reference to the drawings. FIG. 1 and FIG. 2 each show an example of the relationship between the centripetal acceleration and yaw rate with respect to the steering force of the power steering. The one-dot chain line in the figure is a reference line showing the case of manual steering (M/S), and the power steering assist force does not work when the steering force is small, but starts working when the steering force exceeds a certain value. A in the diagram
The lines shown by and C show examples when the steering assist force is decreased, and the lines shown by B and D show examples when the steering assist force is increased.
The upper lines A and B show an example where the understeer characteristics are strengthened, and the lower lines C and D show an example where the understeer characteristics are weakened. In the present invention, depending on changes in suspension characteristics, A and D
The steering characteristics are controlled so that the line shown by (indicated by a solid line) follows. Note that the lines shown in this figure are just one example, and depending on how the suspension characteristics and steering characteristics are determined, the lines B and C may be overlapped, or
It is also possible to reverse the vertical positional relationship. The steering characteristics shown by lines A, B, C, and D control the suspension characteristics and steering characteristics as shown in Table 2 below.

[Table] FIG. 3 shows an automobile equipped with a comprehensive control device according to an embodiment of the present invention. In this embodiment, the damper damping force is Solenoids 21b, 22b that change the spring characteristics or solenoids 21a, 22a that change the spring characteristics.
The suspension characteristics are changed by outputting from the controller 30 an output that operates the two or both, and at the same time, the controller 30 outputs an output that controls the discharge amount of the pump 14 based on the input 30f from the vehicle speed sensor 31 to change the steering characteristics. This output operates the solenoid of the flow rate control valve when the power steering pump is driven by an engine, and controls the rotation speed of the motor when it is driven by an electric motor. FIG. 4 shows a main system diagram of an embodiment of the present invention, which is equipped with a power steering system that obtains assist force from a hydraulic pump driven by an engine. The power steering device of this embodiment is equipped with a rack and pinion type steering as manual steering, and includes a steering shaft 2 rotated by a steering wheel 1.
is connected to the pinion 5 via joints 3 and 4. This pinion 5 is meshed with a rack 6, and at both ends of this rack 6 are knuckle arms 8a, which are rotatably supported around shafts 7a and 7b.
Tie rods 9a and 9b engaged with 8b are connected. Steering wheel 1 is operated,
When the rotation of the steering shaft 2 is transmitted to the rack 6 via the pinion 5, the rack 6 moves in the left-right direction in the figure, rotates the knuckle arms 8a and 8b via tie rods 9a and 9b, and rotates the steering wheels (generally Give the steering angle to the front wheels) 10a and 10b. A piston 11c of a power cylinder 11 is fixed to the rack 6, and a piping 1 communicating with oil chambers 11a and 11b defined by the piston 11c.
2a and 12b are connected to an oil pump 14a via a control valve 13. The control valve 13 has been commonly used in this type of power steering device, and controls the discharge pipe 15 and return pipe 16 of the oil pump 14a to the pipes 12a and 1, respectively, depending on the steering direction.
Switch the hydraulic system to connect to 2b, or 12b and 12a. For example, when the rack 6 is steered to move to the right in the figure, the discharge pipe 1
5 is connected to the pipe 12b, and the return pipe 16 is connected to the pipe 12a. As a result, the rightward movement of the rack 6 is assisted by the hydraulic pressure within the power cylinder 11.
Further, when the steering shaft 2 is not rotating, the control valve 13 allows the discharge pipe 15 and the return pipe 16 to communicate directly, and does not send pressure oil to the power cylinder 11. The oil pump 14a is directly driven by the engine 18 via a belt 17, and a flow rate control valve 19 is interposed in the discharge pipe 15 of the pump 14a. The flow rate control valve 19 includes a valve body 19b that is formed to be slidable in the vertical direction in the drawing within the casing 19a, a spring 19c that urges the valve body 19b downward in the figure, and a flow rate control solenoid 1.
9d, and the casing 19a is the discharge pipe 1.
1st and 2nd ports 19e and 19f connected to 5,
and a third port 19 connected to the return pipe 16
It is equipped with g. When the flow control solenoid 19d is demagnetized, the valve body 19b is pushed by the spring 19c and the third
Port 19g is closed. At this time, the annular groove 19h carved around the valve body 19b aligns with the first and second ports 19e and 19f, and these first and second ports 19e and 19f communicate with each other (as shown in FIG. 4). condition). On the other hand, the controller 30
Flow rate control solenoid 19 with an output of 30g
When d is excited, the valve body 19b is pulled upward in the figure against the biasing force of the spring 19c. Therefore, the third port 19g, which was previously closed by the valve body 19b, is partially closed by the first port 19e.
Since a part of the flow rate from the first port 19e returns to the return pipe 16 through the third port 19g, the flow rate exiting from the second port 19f decreases.
That is, when the flow control solenoid 19d is demagnetized,
The entire discharge amount of the pump 14a flows to the control valve 13, resulting in a large steering assist force, and when the flow control solenoid 19d is energized, a portion of the discharge amount of the pump 14a is bypassed by the flow control valve 19, so that the control valve 13 has a large steering assist force.・Valve 13
The flow rate to the steering assist force decreases. In reality, by changing the ON-OFF duty ratio of this solenoid, the sixth
Controls as shown in FIGS. 7, 7, and 8 are performed. In addition to the input from the power supply, the above-mentioned controller receives an input 30a from the manual switch 32 when switching is possible manually, and an input 30h from the steering angle sensor 33 in this embodiment (this input is not limited to the steering angle but also the load). , vehicle speed, etc.), and outputs signals 30b, 30c, 30d, and 30e that change the suspension characteristics and a signal 30g that changes the steering characteristics based on these inputs. Specifically, the steering characteristics are as described above, and regarding the suspension characteristics, for example, to change the spring characteristics of the air springs 21 and 22, the solenoids 21a and 22a are energized or demagnetized by the outputs 30b and 30c from the controller 30. and turn ON/OFF communication with actuators 21A and 22A.
To change the damping characteristics of the damper, the outputs 30d, 3 from the controller 30 are
This is done by energizing or demagnetizing the solenoids 21b and 22b with 0e and changing the orifice size that determines the damper characteristics. As described above, depending on the steering angle (or driving conditions such as load and vehicle speed), it is possible to control steering characteristics that follow the suspension characteristics using the controller, either by manual switch selection or automatically. FIG. 5 shows a main system diagram of an embodiment of the present invention, which is equipped with a power steering system that obtains assisting force from a hydraulic pump driven by an electric motor. This embodiment is completely the same as the embodiment shown in Fig. 4, except that the hydraulic pump is driven by a motor rather than an engine, and there is no flow control valve, and the same parts are given the same numbers and explained. omitted. In this embodiment, the motor 20 is driven and controlled by the output 30g from the controller 30, and the steering characteristics are changed by controlling the discharge amount of the pump 14b. Similar to the example shown in FIG. 4, this controller can also change the suspension characteristics, so it is possible to control the suspension characteristics and the steering characteristics in a mutually related manner. FIGS. 6, 7, and 8 are graphs illustrating the relationship between the hydraulic pump discharge amount and the steering characteristics in the embodiments described in FIGS. 4 and 5. FIG. In the graph of Figure 6, vehicle speed V and pump discharge amount Q
In general, when the speed is low, that is, when a large steering force is required, the flow rate is large, and as the speed increases, the flow rate decreases, and becomes constant above a certain speed. The difference between the large assist force and the small assist force is determined by changing the deenergization/excitation duty ratio of the solenoid of the flow control valve in the embodiment shown in FIG. 4, and by changing the rotational speed of the motor in the embodiment shown in FIG. , for example, at a vehicle speed of V ₁ , the flow rate changes from Q _L to Q _H. Figure 7 shows the steering torque when the above vehicle speed V ₁ , that is, the flow rate to the power steering is Q _L and Q _H.
This is a graph showing the relationship between T _H and oil pressure P. The oil pressure P does not change much when the steering torque T _H is small.
When the steering torque exceeds a certain value, the oil pressure P increases synergistically. However, to obtain the same oil pressure, the flow rate is
Q _H (less) requires greater torque T _H. Figure 8 is a graph showing the relationship between the centripetal acceleration and the steering torque T _H when the vehicle speed is V ₁ , that is, the flow rate to the power steering is Q _L and Q _H. As the steering torque T _H increases, the centripetal acceleration increases. increase synergistically. In order to obtain the same centripetal acceleration, a larger torque is required when the flow rate is Q _H. In other words, the smaller the flow rate to the power steering, the smaller the assist force and the heavier the steering feel. FIG. 9 shows a control circuit diagram of an embodiment according to the present invention, and shows an embodiment in which suspension characteristics are selected by a manual switch and the power steering hydraulic pump is driven by an engine. Manual switch 32
When OFF, this signal 30a is the controller 30
The signal that is input to the inverter 38 and converted to an ON signal is output to the front wheel suspension 23.
0b, 30d, energizes the solenoid 21a that changes the spring characteristics of the front wheel suspension 23, the solenoid 21b that changes the damping characteristics, or both, while the output 3 remains as an OFF signal.
0c and 30e demagnetize the solenoid 22a that changes the spring characteristics of the rear wheel suspension 24, the solenoid 22b that changes the damping characteristics, or both. In this case, the solenoids 21a and 22a that change the spring characteristics are set so that the spring constant is small when energized (ON) and becomes large when demagnetized (OFF), and the solenoids 21b and 22b that change the damping characteristics are set so that the spring constant is set to be large when energized (ON). ), the damping force is set to be small, and when demagnetized (OFF), the damping force is set to be large. When the manual switch 32 is ON, the above case is reversed, and the solenoid 21a for changing the spring characteristics of the front wheel suspension 23, the solenoid 21b for changing the damping characteristics, or both are demagnetized, and the solenoid for changing the spring characteristics of the rear wheel suspension 24 is demagnetized. The solenoid 22a, the damping characteristic change solenoid 22b, or both are energized. Here, the spring constant of the front wheel suspension is K _F , the damping coefficient is C _F , the spring constant of the rear wheel suspension is K _R ,
The damping coefficient is C _R , and the manual switch 32 is
When the value for ON-OFF is expressed by adding the suffix of ON or OFF, it becomes as follows. (1) Spring constant ratio (K _F / K _R ) ON > (K _F / K _R ) OFF (2) Damping coefficient ratio (C _F / C _R ) ON > (C _F / C _R ) OFF Therefore, manual When the switch is ON, the understeer characteristics are strong, and when the switch is OFF, the understeer characteristics are weak. The above is summarized for clarity as shown in Table 3 below.

[Table] In the present invention, when the suspension characteristics (understeer characteristics) are changed by the aforementioned manual switch, the steering characteristics are also changed at the same time. , and will be explained using FIGS. 11 and 12 together. FIG. 10 is a graph showing the input of the first comparator 37 in the controller 30, FIGS. 11 and 12 are graphs showing the output 30g from the first comparator 37, and FIG.
When 2 is ON, Figure 12 shows manual switch 3.
2 is a graph showing when OFF. When the manual switch 32 is ON, the output from the triangular wave generation circuit 35 is added to the input 30a from the manual switch by the adder circuit 36, and the result is the upper triangular wave shown in FIG. 10 (the line indicated by the manual switch ON in the figure). 1st comparator 3
It is input to the positive side of 7. On the other hand, vehicle speed sensor 3
The input 30f from the first comparator 37 is converted into a voltage by the F/V converter 34 and input to the negative side of the first comparator 37. As an example, considering a certain constant vehicle speed, the voltage V after F/V conversion at that time is shown in FIG. 10 (a straight line represented by a constant value V). When the above two inputs are input to the first comparator 37, the output is T ₁ as shown in FIG.
Time ON, T is issued as a signal to be OFF for ₂ hours,
This is the flow control valve 1 that has an output of 30g and is installed in the discharge side piping of the power steering pump.
The flow rate control solenoid 19d of No. 9 is deenergized and energized.
At this time, the flow rate control solenoid 19d is activated within T time.
It is ON for T ₁ hour and OFF for T ₂ hours, and this duty ratio (T ₁ /T) determines the flow rate that acts as an assist force for power steering through the flow rate control valve 19. When the manual switch 32 is OFF, the positive input of the first comparator 37 is only the output from the triangular wave generation circuit 35, and the overall voltage level is lower than when the manual switch 32 is ON.
This results in the lower triangular wave shown in Figure 10 (the line indicated by the manual switch: OFF in the figure). This results in
Assuming that the vehicle speed is the same as in the above case, the output of the first comparator 37 will be as shown in FIG.
The signal will be ON for T ₃ hours and OFF for T ₄ hours. Therefore, the flow rate control solenoid 19d of the flow rate control valve 19
The de-excitation of is the duty ratio: T ₃ /T, and the flow rate is also determined based on this. Due to the difference between ON and OFF of the manual switch 32, the electric potential of the triangular wave changes as a whole as shown in FIG.
7 becomes different as shown in FIGS. 11 and 12. That is, manual switch 32
When is ON, the flow rate control solenoid 19d is deenergized with a duty ratio of T ₁ /T, and when the manual switch 32 is OFF, the flow rate control solenoid 19d is deenergized with a duty ratio of T ₃ /T. Therefore, the flow rate that passes through the flow control valve and acts as a power steering assist force also differs by the difference in duty ratio; when the manual switch is ON, the flow rate is low and the power steering assist force is small, and when the manual switch is OFF, the flow rate is high and the power steering assist force is low. Assist power increases. As described above, when the manual switch is ON, the understeer characteristics due to the suspension characteristics are strong and the assist force of the power steering is small, and when the manual switch is OFF, the understeer characteristics are weak and the assist force of the power steering is large. This allows the driver to select a maneuvering characteristic with excellent stability at the expense of responsiveness, or a maneuvering characteristic with excellent responsiveness at the cost of stability. FIG. 13 shows a control circuit diagram of another embodiment according to the present invention, and shows an embodiment in which automatic suspension characteristics are selected based on the steering angle and the hydraulic pump for power steering is driven by the engine. There is. In the figure, the same parts as those shown in FIG. 9 are given the same numbers, and the explanation will be omitted. The steering angle is detected by the steering angle sensor 33, and the input 30h from the steering angle sensor 33 to the controller 30 is input to the second comparator 39.
When the steering angle is smaller than a certain set value, the second comparator 39 outputs an ON signal, and when the steering angle exceeds a certain set value, it outputs an OFF signal. The ON or OFF signal from the second comparator 39 controls the suspension characteristics and steering characteristics in exactly the same way as in the embodiment shown in FIG. In other words, when the steering angle is small and the vehicle is traveling straight or nearly straight, the understeer characteristics due to the suspension characteristics are strong, the power steering assist force is small, and the responsiveness is poor, but the steering characteristics are excellent in stability, and the steering angle is large. When turning around curves, the understeer characteristics due to the suspension characteristics are weak, the power steering assist force is large, and the stability is poor, but the steering characteristics are excellent in responsiveness and turning ability, and the steering characteristics are to be made into a so-called sporty car. Can be done. The embodiments shown in FIGS. 9 and 13 show examples in which the power steering hydraulic pump is driven by an engine, but in the case of driving by an electric motor as explained in FIG. Similar flow control can be achieved by controlling the motor rotation speed based on the duty ratio (for example, integrating the output of the first comparator 37 and controlling the rotation speed based on the integrated potential) instead of controlling the flow rate using the excitation duty ratio. The control circuit diagram shown in FIG. 14 performs suspension characteristic control using a steering angle sensor 33 and a vehicle speed sensor 3.
An example is shown in which the amplifier 4 in this figure is
The output of 4b is replaced with the inverting input of second comparator 39 of FIG. 13 to form controller 30A. That is, FIG. 14 is a circuit diagram showing a portion of the controller 30. In this embodiment, the square of the vehicle speed (V ² ) is used as the steering angle (θ) in order to suppress the understeer characteristic as the vehicle speed increases, that is, to suppress roll caused by centrifugal force during steering.
An example of control is shown in which the understeer characteristic is weakened according to the magnitude of the product (θ×V ² ) of the steering angle sensor 33 input to the controller 30A.
output θ and the output S of the vehicle speed sensor 31, the steering angle θ remains unchanged, and the vehicle speed V is obtained by multiplying the output V converted by the converter 41 that converts the output S of the vehicle speed sensor into a voltage by the multiplier 42. After multiplying to obtain V ² , it is input to the multiplier 43 to obtain θ×V ² , and this output θ×V ² is sent to the front and rear wheel actuators 21 a, 21 b, 2 via a buffer 44 a and an amplifier 44 b.
2a and 22b to control the damping force and spring constant. In other words, depending on the magnitude of the product of the vehicle speed (V) squared and the steering angle (θ), the damping force front and rear wheel ratio C _F /C _R or the spring constant front and rear wheel ratio K _F /K _R The magnitude of is controlled so that the larger this value (θ×V ² ) is, the smaller it becomes. This makes it possible to control the suspension characteristics with respect to the steering angle multiplied by the influence of centrifugal force that is proportional to the square of the vehicle speed. Furthermore, by inputting the suspension characteristic control signal to the adder 36 of the example shown in FIG. 13, it is possible to perform steering characteristic control that follows changes in the suspension characteristics, similar to the embodiment shown in FIG. As explained in detail above, according to the present invention, in order to change the steering characteristics in accordance with changes in the suspension characteristics so as to promote changes in the handling characteristics caused by this change, the understeer characteristics are strengthened by the suspension characteristics. When improving stability, the assist force of the power steering is reduced, resulting in more stable handling characteristics, and when reducing understeer characteristics and improving responsiveness, the assist force of the power steering is increased. Furthermore, the vehicle can have handling characteristics with improved responsiveness. In other words, a car with so-called sporty handling characteristics that promotes changes in stability or responsiveness due to changes in suspension characteristics through steering characteristics, making the changes in stability or responsiveness more noticeable to the driver. can be realized.

[Brief explanation of the drawing]

Figures 1 and 2 show the centripetal acceleration relative to the steering force when changing the car's suspension characteristics and steering characteristics (Figure 1).
and yaw rate (Figure 2), Figure 3 is a perspective view of an example of an automobile equipped with the integrated control device of the present invention, and Figure 4 is an example of a vehicle equipped with power steering using an engine-driven hydraulic pump. A main system diagram of an embodiment of the present invention; FIG. 5 is a main system diagram of an embodiment of the present invention equipped with power steering by an electric motor-driven hydraulic pump; FIGS. 6, 7, and 8 are main system diagrams of an embodiment of the present invention. These are graphs showing the relationship between the hydraulic pump discharge amount and the steering characteristics in the example. FIG. 6 is the relationship between the vehicle speed and the pump discharge amount, FIG. 7 is the relationship between the oil pressure and steering torque, and FIG. 8 is the relationship between the steering torque and centripetal. A graph showing the relationship between accelerations, FIG. 9 is a control circuit diagram of an embodiment of the present invention in which suspension characteristics can be selected by a manual switch, FIG. 10 is a graph showing the input of the first comparator, FIGS. Figure 12 shows the output of the first comparator, and Figure 11 shows the manual switch.
12 is a graph showing the values when the manual switch is OFF, FIG. 13 is a control circuit diagram of an embodiment of the present invention in which the suspension characteristics are changed according to the steering angle, and FIG. 14
The figure is a control circuit diagram based on steering angle and vehicle speed. 1... Steering wheel, 2... Steering shaft, 3, 4... Joint, 5... Pinion, 6... Rack, 11... Power cylinder, 13... Control valve, 14a, 14
b... Hydraulic pump, 18... Engine, 19...
Flow rate control valve, 19d...Flow rate control solenoid, 2
0...Motor, 21a, 21b, 22a, 22b
... Solenoid, 21A, 22A ... Accumulator, 30 ... Controller, 31 ... Vehicle speed sensor, 32 ... Manual switch, 33 ... Rudder angle sensor, 34 ... F/V converter, 35 ... Triangular wave generation circuit , 36... Addition circuit, 37... First comparator, 38... Inverter, 39... Second comparator, 41... Converter, 42... Multiplier,
43...Post multiplier, 44a...Buffer, 44
b...Amplifier.

Claims (1)

[Claims] 1. A suspension unit that suspends the vehicle body on each of the front, rear, left, and right wheels; a power steering device that steers a steerable wheel among the wheels;
A first control means for variably controlling the damping force ratio of the front wheels to the rear wheels or the spring constant ratio of the front wheels to the rear wheels by controlling at least one of the damping force or the spring constant of the suspension unit, and an assist for the power steering device. a second control means for variably controlling the force; outputting a first control signal for increasing at least one of the damping force ratio or the spring constant ratio to the first control means; and following the output of the first control signal to control the assist. outputting a second control signal to the second control means to reduce the force and outputting a third control signal to the first control means to reduce at least one of the damping force ratio or the spring constant ratio; The controller includes a controller that outputs a fourth control signal to the second control means so as to increase the assist force in accordance with the output of the control signal, and outputs the power in synchronization with a change in the damping force ratio or spring constant ratio of the suspension unit. A comprehensive suspension and steering control device characterized by changing the assist force of the steering device.