JPS63106133A - Vehicle suspension device - Google Patents

Abstract

PURPOSE:To make it possible to automatically and appropriately control the roll rigidity during a vehicle turning, by providing an active suspension unit, an instructing value creating means, and a turning gain control means. CONSTITUTION:An instructing value creating means 31A creates a predetermined instructing value in accordance with data of lateral acceleration of a vehicle body and a gain which may be changed by an set signal externally applied, and delivers thus obtained value to pressure control valves 17FL through 17RR in active suspension units 11FL through 11RR. The control valve 17FL through 17RR control the working pressures of fluid cylinders 15FL through 15RR in accordance with the received instructing value, and thereby lateral variations in the attitude of the vehicle body are suitably restrained. Meanwhile, a tuning gain control means 31B determines what kind of turn the vehicle body carries out in accordance with a vehicle speed and data of steering angle, and then delivers data of a tuning pattern corresponding the kind of turn to the instructing value creating means 31A. The instructing value creating means 31A changes its gain into a value corresponding to the turning pattern in accordance with the data of the turning pattern.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a suspension device for a vehicle, and in particular,
The present invention relates to a suspension device for a vehicle equipped with an active suspension that is individually interposed between the vehicle body and each wheel and whose operating pressure is controlled based on a predetermined command value.

[Conventional technology]

Conventionally, various types of suspensions have been proposed for suppressing changes in posture of a vehicle while it is running.

Among these, as an active type suspension device, there is, for example, one previously filed by the present applicant as Japanese Patent Application No. 137875/1983. This prior art is equipped with a hydraulic cylinder interposed between the vehicle body and each wheel, and a pressure control valve that can control the operating pressure of this hydraulic cylinder according to only a predetermined command value. It is equipped with a lateral acceleration detector that detects acceleration in the lateral direction, and a control device that changes and controls the command value of the pressure control valve based on the detected value of the lateral acceleration detector and a changeable gain. The vehicle is configured to include mode setting means capable of selecting the roll stiffness of the vehicle relative to lateral acceleration at the driver's seat and outputting the selected value to the control device as a gain change command. In this case, the modes selectable by the mode setting means include, for example, "
There are "zero roll mode", "normal roll mode", "reverse roll mode", etc., and the magnitude of the command value of the pressure control valve with respect to lateral acceleration is controlled corresponding to each of these modes.

[Problem that the invention seeks to solve]

However, in the above-mentioned conventional example, the gain for amplifying the detected lateral acceleration value can be arbitrarily commanded within a predetermined range from the driver's seat, so for example, the passenger can arbitrarily select the roll state when turning. Although there are advantages, for example, if the vehicle is suddenly steered with the "reverse roll state" setting set, the vehicle will suddenly reverse roll, which will significantly worsen the driver's steering feeling. However, there was an unresolved problem in that other occupants also lost the flat feeling that they had in the zero-roll state, which significantly impaired ride comfort.

Therefore, the present invention has been made by focusing on the unsolved problems of the above-mentioned conventional example, and it automatically and accurately controls the roll stiffness when the vehicle turns, thereby improving the steering feeling and riding experience. The object is to provide a suspension device for a vehicle that improves comfort.

Means for Solving the Problems] In order to achieve the above object, the present invention provides an active suspension that is interposed between a vehicle body and each wheel and whose operating pressure is controlled based on a predetermined command value; command value forming means for forming the command value based on lateral acceleration information of the vehicle body and a changeable gain; and determining a turning state of the vehicle body based on vehicle speed or steering angle information of the vehicle body, and determining a turning state of the vehicle body based on the vehicle speed or steering angle information of the vehicle body, and determining a turning state of the vehicle body based on the vehicle speed or steering angle information of the vehicle body, and The present invention is characterized in that it includes a turn gain control means for correspondingly changing the gain of the command value forming means.

[Operation] In the present invention, the command value forming means forms a predetermined command value based on the lateral acceleration information of the vehicle body and a gain that can be changed by a setting signal from the outside, and applies this to the pressure control of the active suspension. Output to valve. The pressure control valve controls the operating pressure of the fluid pressure cylinder according to the input command value, thereby appropriately suppressing changes in the lateral posture of the vehicle body.

On the other hand, the turning gain control means determines the type of turn the vehicle is making, such as whether the vehicle is making a sudden lane change or a slow turn, based on the vehicle speed or steering angle information. and outputs turning pattern information corresponding to this to the command value forming means. The command value forming means changes the gain to a value corresponding to the turning pattern information based on the turning pattern information. For this reason, for example, in the case of the above-mentioned ``sudden lane change,'' the gain is lowered to set the ``zero roll mode,'' and in the case of a ``relaxed turn,'' the gain is increased to set the ``reverse roll mode.''
As a result, the vehicle attitude during turning can be automatically and accurately controlled depending on the type of turning. Therefore, it is possible to improve the steering feeling and riding comfort during turning.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

1 to 7 are diagrams showing a first embodiment of the present invention.

In FIG. 1, 11FL, 11FR, 11RL.

11RR is the vehicle body side member 12 and each wheel 13FL.
.

An active suspension is shown interposed between the wheel side member 14 that individually supports 13FR, 13RL, and 13RR. This active suspension IIFL~1IRR
are respectively hydraulic cylinders 15F and 15F as actuators.
L, 15FR, 15RL, 15RR, coil spring 16FL, 16FR, 16RL, 16
Pressure control valves 17FL, 17FR, 1 that control the working oil pressure for RR and hydraulic cylinders 15FL to 15RH in response only to command values from a control device 31, which will be described later.
7RL.

17RR.

Among these, the hydraulic cylinders 1'5FL to 15RR are used for the front wheel 13FL and the front right wheel 13, as shown in FIG.
They are arranged so as to be independently driven in correspondence with the FR, the rear left wheel 13RL, and the rear right wheel 13RR, respectively. Each of the hydraulic cylinders 15FL to 15RH has a cylinder tube 15a attached to the vehicle body side member 12, and a piston rod 15b attached to the wheel side member 14.

The working oil pressure in the upper pressure chamber B closed by the piston 15c is controlled by each pressure control valve 17FL-17RR. Further, the coil springs 16FL to 16RR are connected to the respective hydraulic cylinders 15FL to 1 between the vehicle body side member 12 and the wheel side member 14, respectively.
It is installed in parallel with the 5RR, and supports the static load of the vehicle body. Here, coil spring 16
Each of FL to 16RR has a relatively low spring constant because it only supports the static load of the vehicle body.

Each of the pressure control valves 17FL-17RR has a cylindrical valve housing 18 and a proportional solenoid 22 integrally formed therein, as shown in FIG. An insertion hole 18a is provided in the center of the spool 18a, and a spool 19 with a spring 21 interposed therebetween and a rod 20 are slidably disposed in the insertion hole 18a. In addition, the valve housing 18 has an insertion hole 1 at one end.
8a and the other end is connected to the hydraulic oil supply side of the hydraulic power source 24 via the hydraulic piping 25, and similarly, one end is connected to the insertion hole 18a and the other end is connected to the drain side of the hydraulic power source 24. Output port 1 connected via hydraulic piping 26
8c, and similarly, one end communicates with the insertion hole 18a and the other end connects to each hydraulic cylinder 1spt, ~15R via a hydraulic pipe 27.
An input/output boat 18d communicating with the upper hydraulic chamber B of R is formed.

The output port 18C has drain passages 18e and 18 communicating between the output port 18C and the upper and lower ends of the spool 19.
f is formed. The spool 19 also includes a land 19a facing the input boat 18b and an output port 18.
A land 19b is formed opposite to the land 19c, and a land 19c having a smaller diameter than both lands 19a and 19b is provided at the lower end of the spool 19. And land 19
A pressure control chamber C is formed between the land 19c and the land 19c, and the pressure control chamber C is connected to the input/output boat 18d via a biloft passage 18g.

On the other hand, the proportional solenoid 22 controls the pressing force of the spring 21 via the rod 20, and the position of the spool 19 is
It has a function of controlling movement between the offset position and the operating positions on both ends thereof.

For this reason, the proportional solenoid 22 includes an actuator 22a that is slidable in the axial direction and an excitation coil 22b that drives the actuator 22a. The drive is controlled by the value V.

Here, the relationship between the command value V and the working oil pressure P output from the output port 18b is as shown in FIG.

That is, when the command value V is zero, a predetermined offset pressure P0 is output, and when the command value V increases in the positive direction from this state, the operating pressure P increases with a predetermined proportional gain of 1. When the output pressure P2 of the hydraulic power source 24 is reached, it becomes saturated. Furthermore, when the command value ■ increases in the negative direction, the operating pressure P decreases in proportion to this.

Therefore, the pressing force from the proportional solenoid 22 is applied to the spool 19 via the spring 21, and in a state where the pressing force of the spring 21 and the pressure in the pressure control chamber C are balanced, the wheel is pressed against a bump on the road surface, for example. When a relatively low frequency vibration input corresponding to the upward sprung mass resonance frequency (or downward vibration input due to passage through the recess) is transmitted, this causes each piston loft 15b of the hydraulic cylinders 15FL to 15RR to move upward ( or downward), and the pressure in the upper hydraulic chamber B increases (or decreases). in this way,
When the pressure in the upper hydraulic chamber B increases (or decreases), the pressure chamber B and the hydraulic piping 271 output port 18d,
The pressure in the pressure control chamber C communicated via the pilot passage 18g rises (or falls), and the balance with the pressing force of the spring 21 is lost. As a result, the spool 19 moves upward (or downward), and the space between the input port 18b and the input/output capo 18d is closed (or opened), and the space between the output capo t-18c and the input/output capo 18d is closed (or opened). -1-1
8d changes in the opening direction (or closing direction), so a part of the pressure in the upper hydraulic chamber B is transferred from the input/output port 18d to the hydraulic source 24 via the output capo 1-18c and the hydraulic piping 26. (or hydraulic pressure is supplied from the hydraulic power source 24 to the upper hydraulic chamber B via the input port 18b, input/output port 18d, and hydraulic piping 27). the result,
The pressure in the upper hydraulic chamber B of the hydraulic cylinders 15FL to 15RR is reduced (or increased), and the pressure increase in the upper pressure chamber B due to upward vibration input (or the pressure decrease in upper pressure chamber B due to downward vibration input) is suppressed. Therefore, the vibration input transmitted to the vehicle body side member 14 can be accurately reduced. At this time, each pressure control valve 17FL to 17RR
Hydraulic piping 26 between the output boat 18c and the hydraulic source 24
Since no diaphragm is provided, no damping force is generated when suppressing upward vibration input.

Here, in FIG. 1, 28H is the pressure control valve 17FL.
28L is a high pressure side accumulator disposed in the middle of the hydraulic piping 25 between 17RR and the hydraulic power source 24, and 28L is the pressure control valve 17FL to 17RR and the hydraulic cylinder 15FL to 15RR.
This is a low-pressure side accumulator that is connected to the hydraulic piping 27 between the two through a throttle valve 28V.

On the other hand, a lateral acceleration detector 29 for detecting lateral acceleration and a steering wheel (not shown) are installed at predetermined positions on the vehicle body.
A steering angle detector 30 is provided to detect the steering angle of the vehicle. The lateral acceleration detector 29 outputs a lateral acceleration detection signal G that is a voltage output that corresponds to the lateral acceleration of the vehicle, and the steering angle detector 30 outputs a steering angle detection signal θ that is a voltage output that corresponds to the steering angle. Each is output to the control device 31.

Furthermore, as shown in FIG. 4, the control device 31 includes a command value forming means 31A that forms a command (Ii! The turning pattern of the vehicle is determined, and the gain K y (Kyf, K
yr) to a value corresponding to the discrimination information.

Among these, the command value forming means 31A is the lateral acceleration detector 29
A lateral acceleration detection signal G is supplied from the gain (amplification degree) K.
By multiplying the output of the front wheel gain adjuster 32f and the rear wheel gain adjuster 32r, which are comprised of variable gain amplifiers that can arbitrarily change yf and Kyr within a predetermined range, and the front wheel gain adjuster 32f by minus 1, It is composed of a sign inverter 33f that supplies the front pressure control valve 17FR, and a sign inverter 33r that similarly inverts the output of the rear wheel side gain regulator 32r and supplies it to the rear right pressure control valve 17RR. The front pressure control valve 17FL also includes a front wheel side gain adjuster 3.
The output of 2f is directly input, and the rear left pressure control valve 17RL
The output of the rear wheel side gain adjuster 32r is directly input to the .

On the other hand, the gains Ky of the gain adjusters 32f and 32r can be changed and controlled as shown in FIG. It is composed of That is, when the gain setting signal S increases, the gain Ky increases at a constant rate, and conversely, when the setting signal S decreases, the gain Ky also decreases.

Further, as shown in FIG. 6, an example of the turning gain control means 31B includes a turning pattern determination section 31Ba and a gain change command section 31Bb. Among these, the turning pattern determination section 31Ba includes absolute value circuits 34A and 34B.
, differentiator 35, comparators 36A, 36B, AND gate 3
7A to 37B. That is, the absolute value circuit 34A takes the absolute value of the manually input steering angle detection value θ and outputs it to the non-inverting input terminal of the comparator 36A installed at the next stage. A reference value 1θs 1 is supplied to the inverting input terminal of this comparator 36A. On the other hand, the differentiator 35 differentiates the input steering angle detection value θ to obtain the steering angular velocity and supplies it to the absolute value circuit 34B.
4B is equipped with the absolute value +0+ of the steering angular velocity at the next stage, and the reference value 1/3. It is designed to be outputted to the non-inverting input terminal of the comparator 36B to which l is supplied.

Here, the set values 1θ, 1 and 1θ, 1 are selected based on experimental values or theoretical values. In other words, when driving in a sudden lane change or slalom, the steering angle is relatively small but the steering angular velocity becomes large; when driving on a gentle curve, both the steering angle and the steering angular speed become small; and when driving on a winding road in the suburbs, the steering angle and steering angular velocity become large. Both angular velocities become large, and in steady circular turns, etc., the steering angle is large but the steering angular velocity is small, so if we plot the steering angle Iθ1 on the horizontal axis and the steering angular velocity 1 1 on the vertical axis, we can create a pattern as shown in Figure 7. become. Therefore, the values corresponding to the boundary positions of each pattern are selected as 1θ, 1 and 1shio, 1.

Then, the comparator 36A outputs a comparison result in which the output becomes a logic H level when 1θ1>1θ, 1, and a logic L level when 1θ1≦1θ, 1. The signals are output to input terminals A of 37B, 37G, and 37D, respectively.

Similarly, the comparator 36B also operates 1θ1>1θ, 1θ1
When +i+≦1, the comparison result becomes a logic H level, and when +i+≦1, the comparison result becomes a logic L level.

Here, when both inputs of the AND gate 37A are at the logic H level, the output becomes the logic H level, and conversely,
AND gate 37D outputs a logic H level when both inputs thereof are at a logic L level. Also, anime games
1-37B, when the input end A on the steering angle θ side is at the logic L level and the input end B on the differential value θ side is at the logic H level, its output becomes the logic H level. Further, the output of AND gate 37C becomes a logic H level when the input condition is opposite to that of AND gate 37B.

Further, the gain change command unit 31Bb includes gate circuits 38A to 38D that open the gates by the H level output of each AND gate 37A to 37D, and a gain adjuster 32f via the gate circuits 38A to 38D. 32
Set signal S to r (SIn S2. S3. S4)
It is composed of signal setting devices 39A to 39D that output . Therefore, when the anti-game controller 37A outputs a logic H level signal, the gate circuit 38A is opened, and the output St (DC voltage) of the signal setter 39A is outputted via the gate circuit 38A. . Similarly, when the gate circuit 38B is opened, the signal setting device 3
When the gate circuit 38C is opened, the output S4 of the signal setter 39C is outputted, and when the gate circuit 38D is opened, the output S2 of the signal setter 39D is outputted.

Here, if the setting signal corresponding to the gain at which the vehicle body is in a zero roll state is 80, it is set so that So''Sz≦33<3.<34.In this way, the output S corresponding to the gain is set to 80. The reason for setting , -S is that we conducted an experiment on a vehicle equipped with an active suspension that can control zero roll and reverse roll, and evaluated the effects of zero roll and reverse roll. When driving, it was found that zero roll gives a flatter feeling and a better driving feeling, and on the other hand, when driving on gentle curves or winding roads in the suburbs, reverse roll provides more comfortable driving. It is.

On the other hand, in this embodiment, the roll stiffness ratio is set to be the same between the front wheels 13FL, 13FR, and the rear wheels 13RL, 13RR. In other words, Vf = K
The command value Vf and VrO value determined by the formula yfXG, Vr = KyrXG are made the same, and neutral steering characteristics are obtained.

Here, in the case where the command value forming means 31A is used exclusively for the neutral steering characteristic, only one set of the gain adjuster 32f and sign inverter 33f, or the gain adjuster 32r and sign inverter 33r is used. This configuration may also be used.

In addition, in this embodiment, the wheel loads of the front and rear wheels of the vehicle and the hydraulic control system loop gain of the hydraulic cylinders 15FL to 15RR1 of the active suspension IIFL-11RR,
The roll stiffness command values Vf and Vr output from the gain adjusters 32f and 32r are formed assuming that the characteristics of the coil springs 16FL to 16RH are mutually equal.

Next, the operation of the above embodiment will be explained.

First, when the ignition switch (not shown) of the vehicle is turned on, this device also starts operating.

That is, when the vehicle travels, the lateral acceleration generated along with this is detected by the lateral acceleration detector 29, and the detected value G corresponding to this is detected by the gain adjuster 32f of the command value forming means.
32r, respectively. Gain adjusters 32f, 32r
Then, the detected value G is set to the gain K y (Ky
f, Kyr) to form command values V (Vf, Vr), which are supplied to pressure control valves 17FL to 17RR.

In this case, assuming that the vehicle is traveling straight on a good road, the detected lateral acceleration value G is zero, so the command value V is also zero, and the proportional solenoid 22 of each pressure control valve 17FL to 17RR is It becomes a de-energized state, and each pressure control valve 17FL
~17RR, a predetermined offset pressure P0 is output to each hydraulic cylinder 15FL~15RR. Therefore, in this state, as described above, the wheels 13FL-13 are separated from the road surface.
The relatively low frequency vibration input input via the RR is
In addition to being absorbed by the movement of the spool 19 due to pressure fluctuations in the pressure control chambers C of the pressure control valves 17FL to 17RR, relatively high frequency vibration input corresponding to the unsprung resonance frequency caused by fine irregularities on the road surface is absorbed by the throttle valve 28V. It is possible to reduce the rate of vibration transmission to the vehicle body and ensure good riding comfort.

Further, for example, if the vehicle is currently turning to the right and the detected lateral acceleration value G is a positive value, the command value V will be a positive value, and the pressure P output from the pressure control valves 17FL and 17RL will be offset. The pressure increases from P0, and the pressure in the upper hydraulic chamber B of the hydraulic cylinders 15FL and 15RL increases. That is, the hydraulic cylinder 15FL.

15RL is in the direction of shrinkage due to the roll,
Since a cylinder urging force is generated that resists the contraction force, an anti-roll effect can be exerted. On the contrary, the pressure P output from the pressure control valves 17FR and 17RR is lower than the offset pressure P0, and the hydraulic cylinder 1
The pressure in hydraulic chamber B of 5FR and 15RH decreases. That is,
Hydraulic cylinder 15FR.

151? R is in the direction of elongation by the rolls, but is controlled to a biasing force that does not promote the elongation force.

On the other hand, if the vehicle is turning to the left and the detected lateral acceleration value V is a negative value, the command value V will be a negative value, and as a result, the opposite control to that described above will be performed, and this will cause the vehicle body to Lateral posture changes are controlled.

On the other hand, as the steering wheel (not shown) is steered, the steering angle detector 30 detects the steering angle and outputs a detection signal θ corresponding to the steering angle to the turning gain control means 31B of the control device 31.

As a result, the turning pattern determining section 31Ba classifies the pattern in which the vehicle is currently attempting to turn, and outputs information corresponding to the pattern to the gain change command section 31Bb.

To explain this in detail, first, the absolute value 1θ of the detected steering angle value θ
If 1 is larger than the set value 1θ, 1 and the absolute value +j+ of the steering angular velocity is smaller than the set value 1sho, 1, only the output of the AND gate 37C becomes a logic H level. As a result, the gate circuit 38C opens and the setting signal S4
are the front wheel side gain adjuster 32f and the rear wheel side gain adjuster 3.
It is output to 2r. Each gain adjuster 32f, 32r has a relatively high gain Ky corresponding to the setting signal S4.

The command values Vf and Vr are set by. That is, assuming that the turning is a steady circular turning, for example, where the steering angle θ is large but the steering angular velocity is relatively small, as shown in area (■) in FIG. 7, the vehicle automatically reverse rolls. As a result, the steering feeling and riding comfort are improved without being affected by operational errors by the occupants as in the conventional example.

Also, the absolute value lθ1 of the detected steering angle value θ is the set value 1θ, 1
If the absolute value 1 of the steering angular velocity θ of the detected value θ is larger than the set value 1
Only the output of 1-37A becomes a logic H level, the gate circuit 38A is opened, and the setting signal S is sent to each gain adjuster 32.
It is output to f, 32r. As a result, the gain K
A command value ■ is formed by a gain Ky1 lower than ya. In other words, assuming that the vehicle is in a state where both the steering angle and the steering angular velocity are large, as shown by region (2) in FIG. 7, when the vehicle is traveling at a relatively high speed on a winding road, etc., It is possible to accurately generate a reverse roll stiffness that is lower than in the case of a conventional vehicle, thereby improving riding comfort and the like.

Also, the absolute value 1θ1 of the detected steering angle value θ is the set value 1θ, 1
and the absolute value of the steering angular velocity θ + (3+ is the set value 1 tide, if smaller than 1, the ant game -) 37D
Only the output of is at logic H level, gate circuit 38D is opened, and setting signal S is output.

is output to each gain adjuster 32f, 32r.

As a result, the gain KY is lower than the gain Ky.
3 forms the command value ■. In other words, the steering angle and steering angular velocity are both smaller as shown in area (■) in Figure 7, which corresponds to driving straight ahead, gentle curves, lane changes, etc., than in area I in Figure 7 described above. A roll stiffness of a low reverse roll state or a substantially zero roll state is generated. Therefore, good riding comfort is reliably maintained.

Furthermore, the absolute value 1θ1 of the detected steering angle value θ is the set value 1.
θ3 smaller than I and the absolute value of steering angular velocity θ 1 sho 1
is larger than the set value 1, 1, only the output of the AND gate 37B becomes a logic H level, and the gate circuit 3
8B is open, and the setting signal S2 is sent to each gain adjuster 32f,
32r. As a result, the gain Ky3
The command value V is formed by a gain K V z lower than .

In other words, the steering angle of the vehicle is relatively small, but the steering angular velocity is very high, as shown in area (■) in FIG.
For example, the zero roll state is assumed to correspond to a sudden lane change or slalom driving. Therefore,
When there is a sudden lane change or the like, the vehicle automatically enters a zero roll state immediately, thereby reliably eliminating the situation where ride comfort etc. deteriorates as in the conventional example.

By the way, since the lateral acceleration detector 29 appropriately detects the lateral acceleration in both directions generated by the operation of the steering wheel as a positive or negative value, the above-mentioned control operates similarly for steering in both directions. Moreover, since the above-mentioned control is executed every time the turning pattern is changed, it is independent of operational errors made by the occupant, and an accurate roll stiffness during turning is automatically set.

Although the above embodiment shows a case where the turning pattern is discriminated into four patterns, the present invention is not necessarily limited to this, and it is possible to further increase the number of discrimination patterns to perform more precise control. You can also do it. Further, the gain may be controlled to change based on a continuous functional expression of the detected steering angle value θ and its differential value θ.

Next, a second embodiment of the present invention will be described with reference to FIGS. 8 and 9. Here, the same reference numerals are used for the same components as in the first embodiment described above, and the description thereof will be simplified or omitted.

Unlike the configuration in which steering angle information is used in the first embodiment, this second embodiment has a configuration in which a turning pattern is inferred and determined based on vehicle speed, and a command value is controlled based on this, and the roll stiffness against lateral acceleration is is controlled appropriately.

To explain this in detail, the second embodiment includes a vehicle speed detector 40 for detecting vehicle speed as shown in FIG. 8, and a detection value V of this vehicle speed detector 40 as shown in FIG. It is equipped with a function generator 41 as a turning gain control means that outputs a gain setting signal S, and is configured to output the output S of the function generator 41 to the gain adjusters 32f and 32r of the command value forming means 31A. ing. And gain adjuster 32
f, 32r is the gain K according to the gain setting signal S.
y can be changed individually.

Here, the function generator 41 outputs a gain setting signal SR having a value that puts the vehicle in a constant reverse roll state in a low speed range where the input vehicle speed detection value V is small, for example up to 50 km/h. For example, in a medium speed range up to 1100 km/h, the setting signal S is lowered to gradually reduce the reverse roll state, and furthermore, in a higher speed range, a setting signal S0 is output that puts the vehicle in a zero roll state. There is.

Therefore, when running a slalom at high speed or making sudden steering, the state automatically becomes zero roll, and when running on a winding road or turning at a steady speed at medium to low speeds, therefore, according to this embodiment, the first embodiment Approximately the same effects as in the example can be obtained.

In addition, in each of the embodiments described above, the entire control device 31 can also be configured using a micro combinator.

Furthermore, in each of the embodiments described above, the stroke between the vehicle body and the wheel may be detected in addition to the pressure control valve, and the hydraulic cylinder may be controlled accordingly.

Further, in each of the above embodiments, the lateral acceleration detector 29 is used as a lateral acceleration detection means, but the present invention is not limited to this, and for example, a vehicle speed sensor and a steering angle (or actual steering angle) are used.
Using a lateral acceleration estimating means which is equipped with a sensor and a means for estimating lateral acceleration based on data output from these, control is performed in the same manner as described above based on the estimated value of this lateral acceleration estimating means. You can also use it as

Further, in each of the embodiments described above, a case has been described in which a hydraulic cylinder is applied as the fluid pressure cylinder, but the present invention is not limited to this, and may be applied to other fluid pressure cylinders such as a pneumatic cylinder. Of course.

Furthermore, in each of the above embodiments, the front wheels 13FL and 13FR
1 and the rear wheels 13RL and 13RR may be appropriately changed to enable understeer or oversteer characteristics.

〔Effect of the invention〕

As described above, according to the present invention, the turning gain changing means determines the turning pattern of the vehicle body based on the steering angle or vehicle speed information, and automatically changes the gain of the command value forming means based on the result of this determination. According to this, for example, it is possible to have a zero roll state when a sudden lane change or a sharp turn is made, and a reverse roll state when driving on a winding road or steady turning, and to prevent the vehicle from occurring when turning. It is now possible to automatically set the roll stiffness to an appropriate value for the lateral acceleration that occurs, thus eliminating the possibility that the roll stiffness setting during turning is affected by erroneous operations, etc., as was the case with conventional models. As a result, the vehicle attitude during turning is accurately controlled, improving steering stability, and beneficial effects such as a good driving feeling for the driver and passengers can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a first embodiment of the present invention, and FIG.
The figure is a schematic sectional view showing an example of a pressure control valve that can be applied to the present invention, FIG. 3 is a graph showing the relationship between the command value for the pressure control valve in FIG. 2 and the output pressure of the pressure control valve, and FIG. is a block diagram showing an example of a control device applicable to the present invention, and FIG. 5 is a block diagram showing an example of a control device applicable to the present invention.
FIG. 6 is a block diagram showing an example of gain control means during turning that can be applied to the present invention; FIG.
FIG. 8 is a block diagram showing a second embodiment of the present invention, and FIG. 9 is an explanatory diagram for pattern discrimination to explain the operation of the first embodiment. FIG. It is a characteristic diagram. In the figure, IIFL to IIRR are active suspensions, 1
2 is the vehicle body side member, 13F to 13RR are wheels, 15FL
~15RR is a hydraulic cylinder, 17FL -17RI? 31A is a pressure control valve, 31A is a command value forming means, 31B is a gain control means during turning, and 41 is a function generator as a gain control means during turning. Patent Applicant Nissan Motor Co., Ltd. Representative Patent Attorney Tetsuya Mori Patent Attorney Yoshiaki Naito Representative Patent Attorney Tadashi Shimizu Figure 2 F1) Figure 4 B - , , , , - Figure 5 6 Figure 8 γ L, , ,, -'' Figure 7 O1est - General traffic signal n1 and others # section 1θ1 Figure 9 □ Vehicle L V (Km/h)

Claims (3)

[Claims] (1) An active suspension that is interposed between the vehicle body and each wheel and whose operating pressure is controlled based on a predetermined command value;
command value forming means for forming the command value based on lateral acceleration information of the vehicle body and a changeable gain; and determining a turning state of the vehicle body based on vehicle speed or steering angle information of the vehicle body, and a result of this determination. A suspension device for a vehicle, comprising: gain control means during turning for changing the gain of the command value forming means in accordance with the above. (2) The turning gain control means multi-divides a plane whose coordinate axes are the absolute value of the steering angle based on the steering angle information and the absolute value of the differential value of the steering angle, and divides each divided surface into one plane. A patent characterized in that the gain is changed by turning pattern information corresponding to a pair-to-one ratio, or turning pattern information based on a function of the absolute value of the steering angle according to the steering angle information and the absolute value of the differential value of the steering angle. A vehicle suspension device according to claim 1. (3) The vehicle suspension according to claim 1, wherein the turning gain control means changes the gain according to the vehicle speed information, and decreases the gain as the vehicle speed increases. Device.