JPH0737204B2 - Suspension device for vehicles - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vehicle suspension device, and in particular,
The present invention relates to a vehicle suspension device equipped with an active suspension that is individually interposed between a vehicle body and each wheel and that has an operating pressure controlled based on a predetermined command value.

[Conventional technology]

BACKGROUND ART Conventionally, various types of suspensions have been proposed as a suspension that suppresses a change in posture of a vehicle during traveling.

Among them, an active suspension device is, for example, one previously filed by the applicant as Japanese Patent Application No. 61-137875. This prior art is equipped with a hydraulic cylinder interposed between the vehicle body and each wheel, and a pressure control valve capable of controlling the operating pressure of this hydraulic cylinder only in accordance with a predetermined command value, A lateral acceleration detector that detects the lateral acceleration 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 the changeable gain are provided. The roll rigidity of the vehicle with respect to the lateral acceleration is selected at the driver's seat, and the control device has a mode setting means capable of outputting it as a gain change command. In this case, the modes selectable by the mode setting means are, for example, "zero roll mode", "forward roll mode", "reverse roll mode".
The magnitude of the command value of the pressure control valve with respect to the lateral acceleration is controlled corresponding to each of these modes.

[Problems to be solved by the invention]

However, in the above-mentioned conventional example, since the gain for amplifying the lateral acceleration detection value can be arbitrarily commanded from the driver's seat within a predetermined range, for example, the occupant can arbitrarily select the roll state during turning. Although there are merits, for example, in the case of performing sudden steering with the "reverse roll state" set, a sudden reverse rolling of the vehicle occurs, which significantly deteriorates the driver's steering feeling. However, there is an unsolved problem that other passengers lose the flat feeling as in the zero roll state and significantly impair the riding comfort.

In order to solve this unsolved problem, JP-A-61-1812
As described in Japanese Patent Publication No. 2, it is conceivable that the steering state is visually inspected by the steering wheel angle and the roll rigidity is automatically controlled by the steering wheel angular velocity, vehicle speed and lateral acceleration when steering is performed. In the conventional example, since the turning state is determined by the vehicle speed and the steering angular velocity, when the steering angular velocity is the same and the lateral acceleration and the vehicle speed are the same, such as a steady circular turning and a gentle lane change, it is necessary to distinguish the turning state. Therefore, it has been desired to grasp the turning state more accurately.

Therefore, the present invention has been made by paying attention to the unsolved problems of the above-mentioned conventional example, accurately grasping the turning state of the vehicle, and automatically and accurately controlling the roll rigidity. It is an object of the present invention to provide a vehicle suspension device designed to improve steering feeling and riding comfort.

Means for Solving Problems] In order to achieve the above object, the present invention provides an active suspension which 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 the lateral acceleration information of the vehicle body and the changeable gain, an absolute value of a steering angle based on the steering angle information and an absolute value of a differential value of the steering angle as coordinate axes. The plane to be divided is divided into multiple parts, and turning is performed by turning pattern information corresponding to each of the divided faces, or by a function of 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. A turning gain control means for changing the gain of the command value forming means according to the pattern information is provided.

[Action]

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 the gain that can be changed by a setting signal from the outside, and outputs this to the pressure control valve of the active suspension. To do. The pressure control valve controls the working pressure of the fluid pressure cylinder in accordance with the input command value, whereby the lateral posture change of the vehicle body is appropriately suppressed.

On the other hand, the turning gain control means determines, based on the vehicle speed or the steering angle information, what kind of turning the vehicle body makes, for example, whether the vehicle is making a sudden lane change or making a slow turning. Is determined and the turning pattern information corresponding to this is output 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 "rapid lane change", the gain is lowered to the "zero roll mode", and in the case of "slow turn", the gain is increased to the "reverse roll mode". Therefore, the vehicle attitude during turning can be automatically and accurately controlled according to the type of turning. Therefore, it is possible to improve the steering feeling and the riding comfort when turning.

〔Example〕

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

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

In FIG. 1, 11FL, 11FR, 11RL and 11RR are active suspensions respectively interposed between a vehicle body side member 12 and a wheel side member 14 that individually supports each wheel 3FL, 13FR, 13RL, 13RR. Indicates. The active suspensions 11FL to 11RR are hydraulic cylinders 15FL, 15FR, 15
RL, 15RR, coil springs 16FL, 16FR, 16RL, 16RR, and hydraulic pressure for hydraulic cylinders 15FL to 15RR, pressure control valves 17FL, 17FR, 17RL, which control only in response to a command value from a control device 31 described later. It has 17RR and each separately.

Among these, as shown in FIG. 1, the hydraulic cylinders 15FL to 15RR are arranged so as to independently drive corresponding to the front left wheel 13FL, the front right wheel 13FR, the rear left wheel 13RL, and the rear right wheel 13RR. ing. Each of the hydraulic cylinders 15FL to 15RR 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 hydraulic pressure in the upper pressure chamber B closed by the piston 15c is controlled by the pressure control valves 17FL to 17RR. In addition, coil spring 16FL ~
16RR, between the vehicle body side member 12 and the wheel side member 14, respectively,
It is equipped in parallel with each hydraulic cylinder 15FL ~ 15RR, which supports the static load of the vehicle body. Here, each of the coil springs 16FL to 16RR has a relatively low spring constant because it only supports the static load of the vehicle body.

As shown in FIG. 2, each pressure control valve 17FL to 17RR has a cylindrical valve housing 18 and a proportional solenoid 22 that is integrally formed with the cylindrical valve housing 18, and among these, the valve housing 18 An insertion hole 18a is provided at the center of the
A spool 19 and a rod 20 with a spring 21 interposed are slidably disposed on the 8a. Further, one end of the valve housing 18 is communicated with the insertion hole 18a and the other end is connected to the hydraulic pressure source 24a.
The input port 18b connected to the hydraulic oil supply side via the hydraulic pipe 25, and the output connected to the drain side of the hydraulic source 24 via the hydraulic pipe 26 at the other end similarly to the input port 18b. Similarly, a port 18c and an input / output port 18d, one end of which communicates with the insertion hole 18a and the other end of which communicates with the upper hydraulic chamber B of each hydraulic cylinder 15FL to 15RR via the hydraulic pipe 27, are formed. The output port 18c is formed with drain passages 18e and 18f which communicate with the output port 18c and the upper end and the lower end of the spool 19. In addition, the spool 19 has an input port 18b
A land 19a facing the output port 18c and a land 19b facing the output port 18c are formed, and a land 19c having a diameter smaller than those of the lands 19a and 19b is provided at the lower end of the spool 19. A pressure control chamber C is formed between the land 19a and the land 19c, and the pressure control chamber C is connected to the pilot passage 18g.
Is connected to the input / output port 18d via.

On the other hand, the proportional solenoid 22 has a function of controlling the pressing force of the spring 21 via the rod 20 and controlling the movement of the position of the spool 19 between the offset position and the operating positions on both ends thereof. Therefore, the proportional solenoid 22 includes an actuator 22a that is slidable in the axial direction and an exciting coil 22b that drives the actuator 22a, and a command that is a drive current output from a controller 31 described later. The drive is controlled by the value V.

Here, the relationship between the command value V and the hydraulic 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 P ₀ is output, and when the command value V increases in the positive direction from this state, the working pressure P increases with a predetermined proportional gain K _1. , Saturates when the output pressure P ₂ of the hydraulic power source 24 is reached. Further, when the command value V increases in the negative direction, the working pressure P decreases in proportion to this.

Therefore, the pressing force of the proportional solenoid 22 is
While being applied to the spool 19 via 21 and the pressing force of the spring 21 and the pressure of the pressure control chamber C are balanced,
When a relatively low frequency vibration input corresponding to an upward sprung resonance frequency due to passage of a convex portion of the road surface (or a downward vibration input due to passage of a concave portion) is transmitted to the wheels, this causes the hydraulic cylinders 15FL to 15RR to move. Each piston rod 15b
Moves upward (or downward), and the pressure in the upper hydraulic chamber B rises (or decreases). In this way, when the pressure in the upper hydraulic chamber B rises (or decreases), the pressure control chamber C communicated with the pressure chamber B via the hydraulic pipe 27, the input / output port 18d, and the pilot passage 18g accordingly. Pressure rises (or falls)
However, the balance with the pressing force of the spring 21 is lost. As a result, the spool 19 moves upward (or downward) to close (or open) the space between the input port 18b and the input / output port 18d, and between the output port 18c and the input / output port 18d. Direction of opening (or closing)
Therefore, a part of the pressure in the upper hydraulic chamber B is discharged from the input / output port 18d to the hydraulic source 24 via the output port 18c and the hydraulic pipe 26 (or from the hydraulic source 24 to the input port 18b, the input / output port). Upper hydraulic chamber B through 18d and hydraulic pipe 27
Is supplied with hydraulic pressure). As a result, hydraulic cylinder 15FL ~
The pressure in the upper hydraulic chamber B of 15RR is reduced (or increased), and the pressure increase in the upper pressure chamber B due to the upward vibration input (or the pressure decrease in the upper pressure chamber B due to the downward vibration input) is suppressed. The vibration input transmitted to the vehicle body side member 14 can be accurately reduced. At this time, since a throttle is not provided in the hydraulic pipe 26 between the output port 18c of each pressure control valve 17FL to 17RR and the hydraulic power source 24, a damping force should be generated when suppressing the upward vibration input. There is no such thing.

Here, in FIG. 1, 28H is a pressure control valve 17FL to 17RR.
High pressure side accumulator disposed in the middle of the hydraulic pipe 25 between the hydraulic pressure source 24 and the hydraulic source 24, 28L is a hydraulic pipe 27 between the pressure control valve 17FL ~ 17RR and the hydraulic cylinder 15FL ~ 15RR via the throttle valve 28V. It is a low pressure side accumulator communicated.

On the other hand, a lateral acceleration detector 29 for detecting lateral acceleration and a steering angle detector 30 for detecting a steering angle of a steering wheel (not shown) are provided at predetermined positions of the vehicle body. Then, the lateral acceleration detector 29 outputs the lateral acceleration detection signal G, which is a voltage output according to the lateral acceleration of the vehicle, and the steering angle detector.
30 is a steering angle detection signal θ which is a voltage output according to the steering angle.
Are output to the control device 31.

Further, as shown in FIG. 4, the control device 31 uses the command value forming means 31A that forms the command value V (Vf, Vr) corresponding to the lateral acceleration detection value G and the vehicle steering angle detection value θ based on the steering angle detection value θ. The turning pattern is determined, and the command value forming means 31A is determined by this determination information.
The gain control means 31B for turning is instructed to change the gain Ky (Kyf, Kyr) in step 1 to a value corresponding to the discrimination information.

Of these, the command value forming means 31A is supplied with the lateral acceleration detection signal G from the lateral acceleration detector 29 and is composed of a variable gain amplifier capable of arbitrarily changing the gains (amplification degrees) Kyf and Kyr within a predetermined range. Minus 1 for the output of the gain adjuster 32f, the rear wheel gain adjuster 32r, and the front wheel gain adjuster 32f.
Multiply by and supply to the front right pressure control valve 17FR Sign inverter 33
f and a sign inverter 33r which inverts the output of the rear wheel gain adjuster 32r and supplies it to the rear right pressure control valve 17RR. The output of the front wheel gain adjuster 32f is directly input to the front left pressure control valve 17FL, and the output of the rear wheel gain adjuster 32r is directly input to the rear left pressure control valve 17RL. ing.

On the other hand, the gain Ky of the gain adjusters 32f and 32r is changed and controlled as shown in FIG. 5 by the gain setting signal S (S _{1 to} S ₄ ) which is supplied from the turning gain control means 32B and consists of, for example, a DC voltage. It is configured to be able to. 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.

An example of the turning gain control means 31B is, as shown in FIG. 6, a turning pattern determination section 31Ba and a gain change command section.
It is composed of 31Bb and. Of these, the turning pattern determination unit 31Ba includes an absolute value circuit 34A, 34B, a differentiator 35, and a comparator 36.
A and 36B, and AND gates 37A to 37B. That is, the absolute value circuit 34A takes the absolute value of the input steering angle detection value θ, and uses this as the comparator 36A installed in the next stage.
Output to the non-inverting input terminal of. The reference value | θ _S | is supplied to the inverting input terminal of the comparator 36A. On the other hand, differentiator
35 differentiates the input steering angle detector θ to obtain the steering angular velocity, and supplies this to the absolute value circuit 34B.
The 4B outputs the absolute value of the steering angular velocity || to the non-inverting input terminal of the comparator 36B, which is provided in the next stage and to which the reference value | _S | is supplied to the inverting input terminal.

Here, the set values | θ _S | and | _S | are selected based on experimental values or theoretical values. That is, in a sudden lane change or slalom traveling, the steering angle is comparatively small, but the steering angular velocity is large.When traveling on a gentle curve, both the steering angle and the steering angular velocity are small. Both angular velocities increase,
Further, since the steering angle is large but the steering angular velocity is small in a steady circular turn, the horizontal axis represents the steering angle | θ | and the vertical axis represents the steering angular velocity ||
Therefore, the value corresponding to the boundary position of each pattern is | θ
Selected as _S | and | _S |.

The comparator 36A is equipped with the comparison result in parallel in the next stage, the output of which becomes a logical H level when | θ |> | θ _S | and the logical L level when | θ | ≦ | θ _S | The AND gates 37A, 37B, 37C, and 37D output to the input terminals A, respectively. Similarly, the comparator 36B outputs to the input terminal B the comparison result which becomes the logical H level when ||> | _S | and the logical L level when || ≦ | _S |.

Here, the AND gate 37A outputs the logic H level when both the forces are at the logic H level, and conversely, the AND gate 37D outputs the output when the both inputs are at the logic level.
The output becomes the logic H level. Also, AND Gate 37B
When the input end A on the steering angle θ side is at the logical L level and the input end B side on the differential value side is at the logical H level, its output becomes the logical H level. Furthermore, the AND gate 37C
When the input condition is opposite to that of the AND gate 37B, its output becomes the logic H level.

Further, as shown in the figure, the gain changing command section 31Bb includes gate circuits 38A to 38D that open the gates by the H level outputs of the AND gates 37A to 37D, and gain adjusters 32f and 32r via the gate circuits 38A to 38D. Setting signal S (S ₁ , S ₂ , S ₃ , S ₄ )
And signal setters 39A to 39D for outputting. For this reason, when the AND gate 37A outputs a signal of logic H level, the gate circuit 38A is opened, whereby the output S ₁ (DC voltage) of the signal setter 39A is output via the gate circuit 38A. . Similarly, gate circuit 3
When the 8B is opened, the output S ₂ of the signal setting device 39B, the output S ₄ of the signal setting device 39C when the gate circuit 38C is opened, and the output S _{3 of the} signal setting device 39D when the gate circuit 38D is opened. Are output respectively.

Here, when the setting signal corresponding to the gain vehicle body becomes zero roll state to S _0, is set such that _{S 0 = S 2 ≦ S 3} <S 1 <S 4. In this way, the reason for setting the outputs S _{1 to} S ₄ corresponding to the gain is to perform an experiment on a vehicle equipped with an active suspension capable of controlling zero roll and reverse roll, and to show the effect of the zero roll and reverse roll. As a result of evaluation, in a sudden lane change or slalom driving, it is better to have a zero roll for a flat feeling and a better driving feeling, and conversely for running on a gentle curve or winding road in the suburbs, it is better to use a reverse roll. This is because it was found that comfortable driving can be obtained.

On the other hand, in this embodiment, the front wheels 13FL, 13FR, and the rear wheels 13RL, 13RR
And the roll rigidity ratios are set to be the same. That is, the values of the command values Vf and Vr determined by the formula of Vf = Kyf × G, Vr = Kyr × G are made the same,
It has a neutral steer characteristic. Here, when dedicated to the neutral steer characteristic, the command value forming means 31A, the gain adjuster 32f and the sign inverter 33f, or only one of the gain adjuster 32r and the sign inverter 33r. It may be configured to be used.

Further, in this embodiment, the wheel loads of the front and rear wheels of the vehicle and the hydraulic cylinders 15 of the active suspensions 11FL to 11RR are used.
FL ~ 15RR, hydraulic control system loop gain, coil spring
The roll rigidity command values Vf and Vr output from the gain adjusters 32f and 32r are formed assuming that the characteristics of 16FL to 16RR are equal to each other.

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

First, when an 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 therewith is detected by the lateral acceleration detector 29, and the detected value G corresponding to this is supplied to the gain adjusters 32f and 32r of the command value forming means. . In the gain adjusters 32f and 32r, the detected value G is multiplied by the gain Ky (Kyf, Kyr) specified by the gay change command unit 31Bb at that time to form the command value V (Vf, Vr), respectively. This is supplied to the pressure control valves 17FL to 17RR.

In this case, assuming that the vehicle is traveling straight on a good road, since the lateral acceleration detection value G is zero, the command value V also becomes zero, and the proportional solenoids of the pressure control valves 17FL to 17RR.
22 is in a non-excited state, and a predetermined offset pressure P ₀ is output from each pressure control valve 17FL to 17RR to each hydraulic cylinder 15FL to 15RR. Therefore, in this state, as described above, the comparatively low frequency vibration input from the road surface via the wheels 13FL to 13RR is applied to the pressure control chamber C of the pressure control valves 17FL to 17RR.
The vibration input of relatively high frequency corresponding to the unsprung resonance frequency due to the fine unevenness of the road surface is absorbed by the throttle valve 28V and is absorbed by the movement of the spool 19 due to the pressure fluctuation of It is possible to reduce the weight and secure a good riding comfort.

Further, for example, if the vehicle is now turning right and the lateral acceleration detection value G is a positive value, the command value V becomes a positive value and the pressure P output from the pressure control valves 17FL, 17RL is offset. The pressure increases from the pressure P ₀ , and the pressure in the upper hydraulic chamber B of the hydraulic cylinders 15FL, 15RL increases. That is, hydraulic cylinder 15F
Although L and 15RL are in the direction of contracting by the roll, they generate a cylinder biasing force that opposes the contracting force, so that the anti-roll effect can be exhibited. On the contrary, the pressure P output from the pressure control valves 17FR and 17RR is lower than the offset pressure P ₀ , and the pressure in the hydraulic chamber B of the hydraulic cylinders 15FR and 15RR is reduced. That is, hydraulic cylinders 15FR, 15R
Although R is in the direction of extension by the roll, it is controlled by a biasing force that does not promote the extension force.

On the other hand, if the vehicle is turning to the left and the lateral acceleration detection value V is a negative value, the command value V becomes a negative value, and in the end, the control opposite to that described above is performed, whereby the vehicle body 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 thereto to the turning gain control means 31B of the control device 31. As a result, the turning pattern determination unit 3
1Ba classifies the pattern that is about to turn and outputs the information corresponding to this to the gain change command unit 31Bb.

This will be described in detail. First, the absolute value of the steering angle detection value θ | θ
When | is larger than the set value | θ _S | and the absolute value of the steering speed || is smaller than the set value | _S |, only the output of the AND gate 37C becomes the logical H level. As a result, the gate circuit 38C is opened, and the setting signal S ₄ is output to the front wheel side gain adjuster 32f and the rear wheel side gain adjuster 32r.
Each gain adjuster 32f, the 32r, command value Vf, is Vr is set by relatively high gain Ky ₄ corresponding to the setting signal S _4.
That is, as shown in a region IV in FIG. 7, the turning is a steady circular turning in which the steering angle θ is large but the steering angular velocity is relatively small. Therefore, unlike the conventional example, the steering feeling and the riding comfort can be improved without being affected by an occupant's operation error or the like.

Further, the absolute value | θ | of the steering angle detection value θ is larger than the set value | θ _S | and the absolute value of the steering angle speed of the detection value θ |
If ｜ is larger than the set value ｜ _S |, AND gate
Only the output of 37A becomes the logic H level, the gate circuit 38A is opened, and the setting signal S ₁ is output to each of the gain adjusters 32f and 32r. As a result, a gain K lower than the gain Ky ₄ is obtained.
The command value V is formed by y ₁ . That is, assuming that the vehicle is in a state in which both the steering angle and the steering angular velocity are relatively high such that the vehicle is traveling on a winding road at a relatively high speed, as shown in the area I in FIG. 7, the area IV in the area IV in FIG. The reverse roll rigidity that is lower than that of the case is accurately generated to improve the riding comfort and the like.

Further, when the absolute value | θ | of the steering angle detection value θ is smaller than the set value | θ _S | and smaller than the absolute value of the steering angular velocity | _S |, only the output of the AND gate 37D becomes the logical H level. The gate circuit 38D is opened, and the setting signal S ₃ is output to the gain adjusters 32f and 32r. As a result, the command value V is formed by the gain Ky ₃ which is lower than the gain Ky ₁ . That is, as shown in the region III of FIG. 7, the vehicle has a small steering angle and a small steering angular velocity and corresponds to straight traveling or a gentle curve, lane change, etc., compared to the case of the region I of FIG. 7 described above. A roll rigidity 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 | θ | of the detected steering angle θ is the set value |
If it is smaller than θ _S | and the absolute value of steering angular velocity || is larger than the set value | _S |, only the output of the AND gate 37B becomes the logic H level, the gate circuit 38B is opened, and the setting signal S ₂ Is output to each of the gain adjusters 32f and 32r. As a result, a gain Ky ₂ lower than the gain Ky ₃ is obtained.
The command value V is formed by. In other words, the vehicle is
As indicated by a region II in the drawing, the steering angle is relatively small, but the steering angular velocity is very high, and this state is set to the zero roll state, which corresponds to the case where, for example, a sudden lane change or slalom traveling is performed. Therefore, in the case of a sudden lane change or the like, the vehicle is immediately put into the zero roll state, which surely eliminates the situation that the riding comfort is deteriorated as in the conventional example.

By the way, the lateral acceleration detector 29 appropriately detects the lateral accelerations in both directions generated by the operation of the steering wheel as positive and negative values. Therefore, the above-described control similarly operates for steering in both directions. In addition, the control described above,
Since it is executed every time the turning pattern is changed, it is not related to an operation error by an occupant, and the roll rigidity at the time of turning is set accurately.

In the above embodiment, the case where the turning pattern is discriminated into four patterns has been shown, but the present invention is not necessarily limited to this, and the number of discrimination patterns can be increased to perform more precise control. You can also Further, the gain may be changed and controlled based on a continuous functional expression of the steering angle detection value θ and its differential value.

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

The second embodiment differs from the structure using the steering angle information in the first embodiment in that the turning pattern is analogized / determined based on the vehicle speed, and the command value is controlled accordingly, and the roll rigidity against lateral acceleration is determined. Is controlled appropriately.

This will be described in detail. In the second embodiment, as shown in FIG. 8, a vehicle speed detector 40 for detecting a vehicle speed, and a vehicle speed detector 40
A function generator as a gain control means at the time of turning for inputting the detected value v of the above and outputting a gain setting signal S as shown in FIG.
41, 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. The gain adjusters 32f and 32r can change their gains Ky according to the gain setting signal S, respectively.

Here, the function generator 41 outputs a gain setting signal S _R having a value that puts the vehicle in a constant reverse roll state in a low speed range up to 50 km / h where the vehicle speed detection value v to be input is small, thereby increasing the high speed. For example, in the medium speed range up to 100 km / h, the setting signal S is lowered so as to gradually reduce the reverse roll state, and in the higher speed range, the setting signal S ₀ for setting the vehicle to the zero roll state is output. Made of

Therefore, when slalom traveling or rapid steering is performed at high speed, the zero roll state is automatically set, and when winding road traveling or steady circular turning traveling is performed at medium to low speed, the reverse roll state is established.

Therefore, according to this embodiment, it is possible to obtain substantially the same operational effects as those of the first embodiment.

In addition, in each of the above-described embodiments, the entire control device 31 may be configured by using a microcomputer.

Further, in each of the above-described embodiments, not only the pressure control valve but also the stroke between the vehicle body and the wheel may be detected, and the hydraulic cylinder may be controlled accordingly.

Further, in each of the embodiments, the lateral acceleration detector 29 is used as the lateral acceleration detecting means, but the present invention is not limited to this. For example, a vehicle speed sensor and a steering angle (or actual steering angle) sensor may be used. It is also possible to use the lateral acceleration estimating means that is equipped with the means for estimating the lateral acceleration based on the data output from these, and to perform the control in the same manner as described above by the estimated value of the lateral acceleration estimating means. .

Furthermore, in each of the above-described embodiments, the case where the hydraulic cylinder is applied as the fluid pressure cylinder has been described, 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-mentioned embodiments, a configuration is added in which the roll rigidity ratio between the front wheels 13FL and 13FR and the rear wheels 13RL and 13RR is appropriately changed, thereby enabling understeer or oversteer characteristics. May be.

〔The invention's effect〕

As described above, according to the present invention, the turning gain changing means for judging the turning pattern of the vehicle body based on the steering angle or the vehicle speed information and automatically changing the gain of the command value forming means on the basis of the judgment result. Since it is configured to be provided, it is possible to accurately distinguish and grasp different turning states such as a steady circular turn with the same steering angular velocity and the same lateral acceleration and vehicle speed, and a gentle lane change, Therefore, for example, the roll rigidity can be set against the lateral acceleration reproduced by the vehicle at the time of turning, such as a zero roll state at the time of a sudden lane change or a sharp turn, and a reverse roll state at the time of winding road traveling or steady turning traveling. It is possible to automatically set to an appropriate value, so the roll rigidity setting during turning as seen in the conventional example is erroneous. It is eliminated that is affected,
The vehicle attitude during turning is accurately controlled to improve the driving stability, and a favorable traveling feeling is obtained for the driving vehicle and passengers.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the first embodiment of the present invention, and FIG.
FIG. 4 is a schematic sectional view showing an example of a pressure control valve applicable to the present invention, FIG. 3 is a graph showing a relationship between a command value for the pressure control valve of FIG. 2 and an output pressure of the pressure control valve, FIG. Is a block diagram showing an example of a control device applicable to the present invention, and FIG. 5 is a gain setting signal S and gain of a gain adjuster.
FIG. 6 is a graph showing the relationship with Ky, FIG. 6 is a block diagram showing an example of a turning gain control means applicable to the present invention, and FIG.
FIG. 8 is an explanatory diagram for pattern discrimination used to explain the operation of the first embodiment, FIG. 8 is a block diagram showing a second embodiment of the present invention, and FIG. 9 is a turning pattern control means of the second embodiment. It is a characteristic diagram. In the figure, 11FL to 11RR are active suspensions, 12 is a vehicle body side member, 13FL to 13RR are wheels, 15FL to 15RR are hydraulic cylinders,
17FL to 17RR are pressure control valves, 31A is command value forming means, 31B is turning gain control means, and 41 is a function generator as turning gain control means.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Namino 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (56) References JP 61-81214 (JP, A) JP 62-34808 (JP, A)

Claims (1)

[Claims] 1. An active suspension, which is interposed between a vehicle body and each wheel and whose operating pressure is controlled based on a predetermined command value, and a lateral acceleration information of the vehicle body and a changeable gain based on the information. A command value forming means for forming a command value, a plane having coordinate axes of 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 are multi-divided, and one is formed for each divided surface. At the time of turning in which the gain of the command value forming means is changed by turning pattern information corresponding to pair 1 or turning pattern information by a function of an absolute value of a steering angle based on the steering angle information and an absolute value of a differential value of the steering angle. A vehicle suspension device comprising: a gain control means.