JPH0332915A - Suspension device of vehicle - Google Patents

Abstract

PURPOSE:To improve the operatability by a driver by providing a setting means, whereby the objective roll angie of a vehicle can be set at will, so as to allow the setting means to change the objective roll angle required for a suspension characteristic control at will based on the rolling mode having been set. CONSTITUTION:Fluid cylinders 3 are installed between a car body 1 and the front wheels and rear wheels 2F and 2R, and the liquid pressure chamber 3c of each fluid cylinder 3 is communicated with a gas spring 5. In addition, proportional flow control valves 9 are provided in the fluid channels 10 fluid supplyably connecting each fluid cylinder 3 and hydraulic pump 8 for making each flow control valve 9 control the flow rate based on the output of a car height displacement sensor 14, upper and lower acceleration sensor 15, and so on by a control unit 17. In this case, a roil mode selection switch Sw, whereby the objective roll angle of a vehicle in turning can be set at will, is provided in such a way that the objective roll angle required for suspension characteristic control can be set at will based on the rolling mode having been set.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a suspension system for a vehicle, and more particularly to an active suspension system that can change the target roll angle as desired. It is.

Prior art A suspension device called a pensive suspension is composed of a hydraulic shock absorber and a damper unit made of a spring such as a coil spring.The suspension characteristics can be adjusted by varying the damping force of the hydraulic shock absorber. Although it is possible to change the characteristics to some extent, the range is small, and in practice, the suspension characteristics of passive suspension devices are set uniformly.

On the other hand, in recent years, a fluid cylinder device has been installed between the sprung mass and the unsprung mass, and a displacement detection means for detecting the displacement of the vehicle has been installed to control the supply and discharge of working fluid to the fluid cylinder device. A suspension device called an actif suspension has been proposed, which can change suspension characteristics as desired by controlling based on the amount of displacement of the vehicle body detected by a displacement detection means (for example, Japanese Patent Publication No. 59-14365
No. 63-130418, etc.).

Generally, there are three types of vehicle vibration: bounce, pitch, and roll, and such active suspension systems include a fluid cylinder device for each wheel.
Using a predetermined control gain that is set and controlled based on the amount of displacement of the vehicle body detected by the displacement detection means, the opening degree of the flow control valve of the fluid cylinder device of each wheel is adjusted to improve riding comfort and running stability. The present invention attempts to control the supply and discharge amount of working fluid to each fluid cylinder device in accordance with the vibrations of the three types of vehicles mentioned above.

Problems to be Solved by the Invention As described above, the active suspension device adjusts each wheel to improve riding comfort and running stability against three types of vehicle vibrations, depending on the driving condition of the vehicle. In order to control the supply and discharge of working fluid to the fluid cylinder device with a predetermined control gain, the operating state of the vehicle is detected,
The suspension characteristic control means is equipped with a suspension characteristic control means for changing the setting of each control gain, and this suspension characteristic control means is based on the lateral acceleration acting on the vehicle, and according to a predetermined driving mode, when the vehicle turns. The target roll angle is automatically set, and the supply and discharge of working fluid to each fluid cylinder device is controlled so that the vehicle body reaches this target roll angle, thereby controlling the vehicle body posture. Ta. Therefore, with conventional active suspension devices, the driver cannot change the target roll angle setting according to the driver's preference, and for example, when the driver turns, the vehicle body tilts relatively largely toward the inside of the turn. Even when a vehicle body posture such as so-called reverse roll is desired, the suspension characteristic control means controls the vehicle body posture based on a preset target roll angle. was unable to respond.

OBJECTS OF THE INVENTION The present invention provides a displacement detection means for detecting displacement of the vehicle, which includes a fluid cylinder device for each wheel between the sprung mass and the unsprung mass of the vehicle, and the displacement detection means. Based on the displacement of the vehicle detected by the vehicle, suspension characteristics are set and controlled according to the driving state of the vehicle so as to cancel out the displacement of the vehicle, and the amount of supply and discharge of working fluid to the fluid cylinder device is controlled. In an active suspension system equipped with suspension characteristic control means, the driver can set the target roll angle of the vehicle when turning as desired, thereby realizing the desired vehicle body posture requested by the driver. It is an object of the present invention to provide an active suspension device that can improve the operability of a vehicle by a driver.

Structure and Function of the Invention An object of the present invention is to provide the above active suspension system with a driving mode setting means capable of setting the eye and ring roll angle of the vehicle during turning as desired; This is achieved by comprising a target roll angle changing means for changing the setting of a target roll angle in the suspension characteristic control means based on the selected driving mode.

According to the present invention, the target roll angle can be set as desired by setting the travel mode halfway, and the target roll angle changing means can change the setting of the target roll angle in the suspension characteristic control means. The suspension characteristic control means can realize the posture of the vehicle body desired by the driver.

For example, if the driver desires a relatively large reverse roll attitude when turning, the driver selects a driving mode in which the target roll angle during turning is set to a large reverse roll angle using the driving mode setting means. The target roll angle changing means changes the setting to a relatively large target roll angle based on the driving mode set by the driving mode setting means, so that the suspension characteristic control means adjusts the attitude of the vehicle body to this driving mode. The supply amount and discharge amount of the working fluid to the fluid cylinder device can be controlled so that the roll angle reaches the target roll angle set by the roll angle setting means, and the vehicle body can be tilted significantly toward the inside of the turn.

According to a preferred embodiment of the present invention, the target roll angle is set as a target roll displacement amount corresponding to a target intersection of the left and right height directions of the vehicle body in the roll control section of the suspension characteristic control means. Further, the driving mode setting means includes a normal driving mode and a reverse roll driving mode, and when the reverse roll driving mode is selected,
The target roll angle changing means changes the target roll displacement amount to a value set to be considerably larger on the reverse roll side than in the normal running mode. Therefore, when the reverse roll driving mode is selected, the vehicle can turn with a relatively large inclination toward the inside of the turn.

According to a more preferred embodiment B of the present invention, when a predetermined driving state, for example, a high-speed driving state exceeding a predetermined vehicle speed, is detected, the driver's sense of security or Emphasizing driving stability, the suspension characteristic control means cancels the setting of the target roll displacement amount on the reverse roll side, and changes the target roll displacement amount to the target roll displacement amount set when the normal driving mode is selected. change to the displacement amount.

EXAMPLES Hereinafter, examples of the present invention will be described in detail based on the attached spout.

FIG. 1 is an overall schematic diagram of a vehicle including a vehicle suspension device according to an embodiment of the present invention.

Although only the left side of the vehicle body 1 is shown in FIG. 1, the right side of the vehicle body 1 is similarly constructed. In FIG. 1, there are fluid cylinder devices 3. between the vehicle body 1 and the left front wheel 2PL and between the vehicle body 1 and the left rear wheel 2RL, respectively.
3 is provided. A hydraulic chamber 3c is formed within each fluid cylinder device 3 by a piston 3b fitted into a cylinder body 3a. The upper end of the piston rod 3d connected to the piston 3b of each fluid cylinder 3 is connected to the vehicle body l, and each cylinder body 3a is connected to the left front wheel 2.
It is connected to the PL or left rear wheel 2R.

The hydraulic chamber 3c of each fluid/linda device 3 communicates with the gas spring 5 through a communication path 4, and each gas spring 5 is divided into a gas chamber 5f and a hydraulic chamber 5g by a diaphragm 5e. The hydraulic chamber 5g can supply fluid to each fluid cylinder device 3 and the hydraulic pump 8 which communicates with the hydraulic pressure chamber 3C of the fluid cylinder device 3 through the communication path 4 and the piston 3b of the fluid/linda device 3. Proportional flow control valves 9.9 for controlling the flow rate of fluid supplied to the fluid cylinder device 3 and the flow rate of fluid discharged from the fluid cylinder device 3 are provided in the fluid passages 10 connected to the fluid cylinder device 3, respectively. ing.

The hydraulic pump 8 has a discharge pressure needle 1 that detects the discharge pressure of fluid.
2 is provided, and a hydraulic chamber 3 of each fluid cylinder device 3 is provided.
A hydraulic pressure sensor 13, t3 for detecting the hydraulic pressure in C is provided.

Further, a vehicle height displacement sensor 14.14 is provided which detects the cylinder stroke amount of each fluid cylinder device 3 and detects the vertical displacement of the vehicle body relative to each wheel 2FL, 2RL, that is, the vehicle height displacement. A vertical acceleration sensor 15.1 that detects the vertical acceleration of the wheels 2PL and 2RL, that is, the vertical acceleration of the springs of the wheels 2PL and 2RL.
5.15 is on the substantially horizontal plane of the vehicle, the left and right front wheels 2PL,
A total of three sensors are provided, one each above the 2PR and one at the center of the left and right rear wheels in the vehicle width direction, and a steering angle sensor 18 and a vehicle speed sensor 19 are also provided, respectively.

Detection signals from the discharge pressure needle 12, hydraulic pressure sensor I3.13, vehicle height displacement sensor 14.14, vertical acceleration sensor 15, I5.15 steering angle sensor 18, and vehicle speed sensor 19 are sent to a control unit 17 having a CPU, etc. therein. Based on these detection signals, the control unit 17 performs calculations according to a predetermined program and controls the proportional flow rate control valve 9.9 as desired.
The suspension characteristics are configured to be variably controlled.

In this embodiment, a roll mode selection switch 3w is provided that can change the suspension characteristic control by the control unit 17 according to the driver's judgment or preference. There is a normal driving mode in which the suspension characteristics are controlled to improve ride comfort or driving stability, and a mode in which the hydraulic pressure of the fluid cylinder device 3 of the wheel on the outside of the turn is controlled relative to the other, focusing exclusively on the preferences of the driver. The vehicle is configured to be able to switch between a reverse roll mode and a reverse roll mode in which the target roll angle of the vehicle is set larger on the reverse roll side than when the normal driving mode is set. Each mode selection signal from the roll mode selection switch S1 is transmitted manually to the control unit 17, and the control unit 17 variably controls the suspension characteristics according to the selected mode.

FIG. 2 shows a fluid cylinder device 3.3.
FIG. 3.3 is a circuit diagram of a hydraulic circuit for supplying fluid to or discharging fluid from these.

In FIG. 2, the hydraulic pump 8 is a hydraulic pump 21 for a power steering device driven by a drive source 20.
An accumulator 22 is connected in communication with a discharge pipe 8a which is connected and arranged in parallel with the hydraulic pump 21 and discharges fluid from the hydraulic pump 21 to the fluid cylinder device 3.3.3.3.
On the downstream side of the connecting portion of the accumulator 22, it branches into a front wheel side pipe 23F and a rear wheel side pipe 23R. The front wheel side piping 23F branches into a left front wheel side piping 23FL and a right front wheel side piping 23FH on the downstream side of the branching part with the rear wheel side piping 23R, and the left front wheel side piping 23FL and the right front wheel side piping 23PR are, respectively, Fluid cylinder device ff3FL for left front wheel and fluid cylinder device 3F for right front wheel
It communicates with the R hydraulic pressure chambers 3c, 3c. Similarly, the rear wheel side pipe 23R is connected to the left rear wheel side pipe 23R on the downstream side of the branching part.
L and the right rear wheel side pipe 23RR, and the left rear wheel side pipe 23RL and the right rear wheel side pipe 23RR are connected to the fluid of the fluid cylinder device 3RL for the left rear wheel and the fluid cylinder device 3RR for the right rear wheel, respectively. It communicates with the pressure chambers 3c, 3c.

These fluid cylinder devices 3FL, 3FR, 3RL.

3RR has gas springs 5FL, 5FR, 5, respectively.
RL and 5RR are connected, each gas spring 5FL
.

5FR, 5RL, and 5RR are the four gas spring units 5a, 5b, 5c, and 5d, and the gas spring units 5a, 5b, 5c, and 5d of the cholera are respectively the corresponding fluid cylinder devices 3FLS3FR.

3RL and 3RR hydraulic chamber 3c% 3CX 3C,3
C; Branch communication paths 4a, 4b, 4 are connected to the communicating path 4.
They are connected by c and 4d. In addition, each gas spring 5F
Branch communication path 4a for L, 5FR, 5RL, and 5RR.

4b, 4c and 4d each have an orifice 25
a -25b % 25c s 25 d is provided, this'+, t! J fiss 25as 25b,
25c.

Damping action of 25d and gas springs 5FL, 5FR, 5R
L.

Due to the buffering effect of the gas sealed in the gas chamber 5f of the 5RR, high frequency vibrations applied to the vehicle are reduced.

Of the gas spring units 5as 5b, 5Cs 5d constituting each gas spring 5FL, 5FR, 5RL, and 5RR, each fluid cylinder device 3FL, 3FR, 3RL, and 3
In the communication path 4 between the first gas spring unit) 5a provided at the position closest to the hydraulic pressure chambers 3c, 3c, 3c, and 3c of the RR and the second gas spring unit) 5b adjacent thereto, ,
By adjusting the passage area of the communication passage 4 between the open position where the communication passage 4 is opened and the closed position where the passage area is narrowed, the damping force of the gas springs 5FL, 5FL, 5RL, and 5RR is switched between two stages. A valve 26 is provided. FIG. 2 shows the switching valve 26 in the open position.

An unload relief valve 28 is connected to the discharge pipe 8 a of the hydraulic pump 8 near the upstream side of the connection part of the accumulator 22 .
When the oil discharge pressure measured in step 2 is equal to or higher than a predetermined upper limit value, the position is switched to the open position, and the oil discharged from the hydraulic pump 8 is directly returned to the reserve tank 29, so that the accumulated pressure of the hydraulic pressure in the accumulator 22 reaches a predetermined value. Controlled to hold the value. In this way, oil is supplied to each fluid cylinder device 3 from the accumulator 2 which is maintained at a predetermined pressure accumulation value.
This is done using soy sauce from step 2. FIG. 2 shows the unload relief valve 28 in the closed position.

Since the hydraulic circuits for the left front wheel, right front wheel, left rear wheel, and right rear wheel are configured in the same way, only the hydraulic circuit for the left front wheel will be explained below, and the rest will be omitted. do.

The proportional flow control valve 9 is a three-way valve, with a closed position where all ports are closed, a supply position where the left front wheel side piping 23FL is opened to the hydraulic pressure supply side, and a fluid cylinder device 3 of the left front wheel side piping 23FL connected to the return piping 32. It is designed to be able to take three positions, including a communicating discharge position. FIG. 2 shows the proportional flow control valve 9 in the closed position. Further, the proportional flow rate control valve 9 includes pressure compensating valves 9a, 9a.
When the proportional flow control valve 9 is in the supply position or the discharge position, the pressure compensation valves 9a, 9a
The hydraulic pressure within the hydraulic pressure chamber 3C of the fluid cylinder device 3 is maintained at a predetermined value.

A pilot pressure-responsive opening/closing valve 33 that can open and close the left front wheel side piping 23FL is provided on the fluid cylinder device 3 side of the proportional flow rate control valve 9. When the solenoid valve 34 that guides the hydraulic pressure of the left front wheel side piping 23FL on the hydraulic pump 8 side of the proportional flow rate control valve 9 is opened, the hydraulic pressure of the solenoid valve 34 is introduced as pilot pressure into the on-off valve 33. When the pressure is above a predetermined value, the on-off valve 33 opens the left front wheel side pipe 23FL, allowing the proportional flow rate control valve 9 to control the flow rate of fluid to the fluid cylinder device 3.

Further, an IJ valve 35 that opens when the fluid pressure in the fluid pressure chamber 3C of the fluid cylinder device 30 increases abnormally and returns the fluid in the fluid pressure chamber 3C to the return pipe 32, on the downstream side of the accumulator 22 connection part. Discharge pipe 8 of nearby hydraulic pump 8
a, opens when the ignition is turned off, and stores the oil stored in the accumulator 22 into the reserve tank 29.
When the oil discharge pressure of the hydraulic pump 8 increases abnormally, the oil in the hydraulic pump 8 is returned to the reserve tank 29, and the hydraulic pump A return accumulator 38.8 is connected to the hydraulic pump relief valve 37 and the return pipe 32 to lower the oil discharge pressure of the fluid cylinder device 3, and performs a pressure accumulating action when fluid is discharged from the fluid cylinder device 3.
38 are provided respectively.

3A and 3B show the control unit) 17
2 is a block diagram of a suspension characteristic control device in the vehicle.

In FIGS. 3A and 3B, the suspension characteristic control device provided in the control unit 17 according to the present embodiment includes a vehicle height sensor 14, 14, 14 for each wheel.
and 14 vehicle height displacement signals XFII, XFLSXllll
A control system A that controls the vehicle height to the target vehicle height based on SXIL, and a vehicle height displacement signal XFIsX p L s X *
* Based on the vehicle height displacement speed signal YFI, YFL s Y** % YIL obtained by differentiating SX I L,
A control system B that suppresses the vehicle height displacement speed, and a vertical acceleration signal Get of the three vertical acceleration sensors 15, 15 and 15,
Control system C that aims to reduce vertical vibration of the vehicle based on GFtSGm and hydraulic pressure sensors for each wheel 13.13.13
．． 13 pressures in 1 word PFI, PFL, PillsFIL
Based on this, the control system calculates the torsion of the vehicle body and suppresses it.

Control system A adds the output X F I SX F L of the vehicle height sensor 14.14 of the left and right front wheels 2PL and 2PR, and also adds the output X t of the vehicle height sensor 14.14 of the left and right rear wheels 2RL and 2RR. Add RSX I L,
Bounce component calculation unit 40 that calculates the bounce component of the vehicle
, left and right front wheels 2FL, 2PR vehicle height sensor 14.14
From the added value of the output XpIXpL, the left and right rear wheels 2R
L, 21tR vehicle height sensor ■4.14 output X l
Pitch component calculation 8411 Left and right front wheels 2P+ which calculates the pitch component of the vehicle by subtracting the added value of SX I L
,, 2PR vehicle height sensor 14.14 output XFIIS
XFL difference XFR-XFL and left and right rear wheels 211L,
2RR vehicle height sensor 14.14 (7) output Xll, x
A roll component calculation unit 42 is provided that calculates a roll component of the vehicle by adding the difference X1ll XIL.

In addition, the control system A receives the bounce component of the vehicle calculated by the bounce component calculation unit 40 and the target average vehicle height T□, and controls the fluid cylinder device 3 of each wheel in the bounce control based on the gain of 1. The pitch component of the vehicle calculated by the bounce control unit 43 and pitch component calculation unit 41 that calculates the fluid supply amount is manually input, and the fluid is supplied to the fluid cylinder device 3 of each wheel in pitch control based on the gain K p l. The roll component calculated by the pitch control unit 44 and the roll component calculation unit 42 that calculate the amount and the target roll displacement amount TI corresponding to the target roll angle of the vehicle body 1 are input, and the target roll displacement amount TI is input based on the gains KRFI, K□, A roll control unit 45 is provided that calculates the amount of fluid supplied to the fluid cylinder device 3 of each wheel in roll control so that the vehicle height corresponds to the roll displacement amount T11.

The target roll displacement amount Tl is determined by four predetermined values T□, TR2
, TR3 and T++4 based on the driving state of the vehicle and the mode selection signal from the roll mode selection switch Sw. Based on the detected vehicle speed detection signal, the displacement amounts T1, TR2, and T are determined according to the value of the acceleration Gs of the vehicle in the horizontal direction calculated by a lateral acceleration calculation means (not shown) when the vehicle is traveling in the normal driving mode. , set to one of
Also, when driving with the reverse roll mode selected, the displacement I
It is set to any one of T, T112, T113, and T negative. Note that the predetermined values To, T12, TR3, and T1
4 is a value such that Ti+ < TR2 < T113 < T14, for example, Q mm, 3ml1115IIlff
i and 10 strokes respectively.

In this way, each control amount calculated by the bounce control unit 1143, the pitch control unit 44, and the roll control unit 45 has its sign reversed for each wheel.
．． 14. Vehicle height displacement signal detected on 14.14 x, 5
XFLSXllll,
The pitch and roll control amounts are added together,
Flow rate signal QF to the proportional flow rate control valve 9 of each wheel in control system A.

QFLI, Qii+, and QRLI are obtained.

In addition, each vehicle height sensor 14.14.14.14, bounce calculation section 40, pitch calculation section 41, and roll calculation section 42
A dead zone device 70.70.70.70 is provided between the vehicle height sensor 14.14.14.14 and the vehicle height displacement signal XFlq XFL, Xllll% XIL from the vehicle height sensor 14.14. XMXo, X++
Only when SX□ is exceeded, these vehicle height displacement signals
F I SX F L s X l l, XIL are output to the noise calculation section 40, the pitch calculation section 41, and the roll calculation section 42.

Control system B receives vehicle height displacement signals xpa and XPLSX input from vehicle height sensors 14, 14, and 14.
111 % X If L is differentiated, and according to the following formula, the vehicle height displacement speed signal Y p @ XY F L % Y
Differentiator that calculates @ l SY I L 46.46.
46.46.

Y= (X, -X,, >/T where xo is the amount of vehicle height displacement at time t, Xh-l is the amount of vehicle height displacement at time t-l, and T is the sampling time.

Furthermore, the control system B generates a vehicle height displacement speed signal Y-lY of the left and right rear wheels 2RL and 2RR from the added value of the vehicle height displacement speed signal YpLs YpH of the left and right front wheels 2PL and 2PR.
A pitch component calculation unit 41a that calculates the pitch component of the vehicle by subtracting the added value of ll, and left and right front wheels 2FL, 2.
Difference Y□ between vehicle height displacement speed signals Y, L, Y, , on the PR side
-YPL and the difference Y, -YIL between the vehicle height displacement speed signals Y, L, Y, of the left and right rear wheels 2RL, 2RR side, and calculates the Ronyl component of the vehicle.
7b.

In this way, the pitch component calculated by the pitch component calculation R47a is manually input to the pitch control section 48, and the gain KP is
2, each proportional flow control valve 9 in pitch control
The flow rate control amount to the roll component calculation unit 4 is calculated.
The pitch component calculated in step 7b is the roll system 2#JB.
49, and the flow rate control amount to each proportional flow control valve 9 in roll control is calculated based on the gains KIF2 and K112.

Further, each control amount calculated by the pitch control section 48 and the roll control section 49 has its sign reversed for each wheel, that is, the vehicle height displacement speed calculated by the differentiator 46, 46, 46, 46. Signal Y p II %YFL-I YI
ILSYIL is reversed so that its sign is opposite, and then the pitch and roll control amounts for each wheel are added, respectively, and a flow signal is sent to the proportional flow control valve 9 of each wheel in control system B. GFI2, Q, L2,
Q10 and QIIL□ are obtained.

The control system C adds the outputs G F I X G F L SG @ of the vertical acceleration sensors 15, 15 and 15,
Bounce component calculation unit 50 that calculates the bounce component of the vehicle
and the sum of 1/2 of the outputs of the vertical acceleration sensors 15.15 installed above the left and right front wheels 2PR and 2PL (Gpi
+ GFL ) / 2, a pitch component calculation unit 51 calculates the pitch component of the vehicle by subtracting the output G of the vertical acceleration sensor 15 provided at the center of the left and right rear wheels in the vehicle width direction; Output GF of side vertical acceleration sensor 15
The calculation value of the bounce component calculated by the roll component calculation unit 52 and the bounce component calculation unit 50 that calculates the roll component of the vehicle by subtracting the output GFL of the vertical acceleration sensor 15 on the left front wheel side from I is input, Based on the gain Ka3, the calculated value of the pitch component calculated by the bounce control section 53 which calculates the control amount of fluid to each proportional flow rate control valve 9 in bounce control and the pitch component calculation section 51 is manually input, and the gain KP2 is calculated. Based on this, the pitch control unit 54 which calculates the control amount of fluid to the proportional flow rate control valve 9 in pitch control, and the pitch component calculation unit 52 calculate the pitch component calculation value manually, and the gain KIF3,
Pitch control unit 5'4 that calculates the amount of fluid to be controlled to the proportional flow rate control valve 9 in pitch M control based on the pitch M control.
and a roll control section 55.

In this way, the bounce control section 53, the pitch control section 5
4 and the control amount calculated by the roll control unit 55, the positive and negative values are reversed for each wheel, and then the bounce, pitch, and roll control amounts for each wheel are added, and the control amount is output from the control system C. Flow signal QPR3QFL3, Q@@2 and Q, L3 to each proportional control valve 9
is obtained.

Note that a dead band device 80.80.80 is provided between the vertical acceleration sensor 15.15.15 and the bounce component calculation section 50, pitch component calculation section 51, and roll component calculation section 52, and the vertical acceleration sensor 15.15. 15. Only when the vertical acceleration signals GFR□ and GFLSGl output from 15 exceed the preset dead zones Xc, Xc, and
P L SG @ is output to a bounce component calculation section 50 , a pitch component calculation section 51 , and a roll component calculation section 52 .

The control system uses the hydraulic pressure detection signal P F of the hydraulic pressure sensor 13.13 of the fluid cylinder device 3 of the left and right front wheels 2PL and 2PR.
L 1P FIL is input, left and right front wheels 2FR, 2P
The ratio of the difference PFRPFL between the hydraulic pressures of the hydraulic pressure chambers 3c and 3c of the fluid cylinder device 3 of L and their added value PFl+PFL pt = (Ppm-PFL) / (PPl+PP
Perform L).

The calculated hydraulic pressure ratio Pt is the threshold hydraulic pressure ratio ω,
On the other hand, if -ωL < Pr < ω, the calculated hydraulic pressure ratio Pr is output as is, and on the other hand, Pr
<- or Pr>ω, the front wheel side hydraulic pressure ratio calculating section 60a1 outputs the threshold hydraulic pressure ratio -ω or ωL, and similarly, the left and right front wheels 2RL, 2
A hydraulic pressure detection signal PRLS'PR11 is input from the hydraulic pressure sensor 13.13 of the fluid cylinder device 3 of the RR, and the hydraulic pressure chambers 3c of the fluid cylinder devices 3 of the left and right front wheels 2PR, 2PL,
The ratio of the hydraulic pressure difference PRRPRL of 3c to the sum of these values pHR + PIL is Pa = (PRIIFIL) / (P
RIIFIL), and a rear wheel side hydraulic pressure ratio calculation R60b that calculates the rear wheel side hydraulic pressure ratio P□ based on the gain ωF.
The output of the warb control section 60 is multiplied by a predetermined value using a gain ω, and then subtracted from the ratio P of the hydraulic pressure on the front wheel side. , is multiplied by a predetermined value using gain ωC, and further, one is reversed so that the controlled amount of fluid supplied to each wheel is opposite in positive and negative between left and right wheels, and each proportional flow control valve 9 in the control system is Flow rate signal QF14Q, L4, Q, .
, ,Q,L, are obtained゛.

Each control system A, B, C and D obtained as above
The flow signals to each proportional flow control valve 9 in are added for each wheel to obtain the final total flow signals QF3, QFL, Q11, and Q to each proportional flow control valve 9.

FIG. 4 shows the target roll displacement amount T in the control system A,
2 is a flowchart showing a setting method.

In FIG. 4, based on the vehicle steering angle detection signal e detected by the steering angle sensor 18 and the vehicle speed detection signal V detected by the vehicle speed sensor 19, the control unit 17
The lateral acceleration Gs applied to the vehicle is calculated by a lateral acceleration calculation means (not shown) provided in the vehicle (S2.3
), the acceleration Gs is a predetermined value G''' l % G s 2,
It is determined whether the predetermined values Gs, , Os, , Gs are greater than Gs (34 to 6).

are set to values such as Gs, Gs2 x Gs, for example, 0.1G, 0.3G, and 0.5G, respectively. When the lateral acceleration Gs is less than a predetermined value Gs, for example 0.1 G, the target roll displacement amount TR is set to a predetermined value T□, for example 0 degrees (S4.512).

When the roll mode selection switch 3w is selected to the normal running mode (31), and when the lateral acceleration Gs is less than the predetermined value Gs, for example 0.3G, the target roll displacement amount T11 is also set to the predetermined value. T1, e.g. Omca
l: Set (S4, S5, S7.512). That is,
Since it is determined that the vehicle is traveling straight or in a gentle turning state, the suspension characteristic control means sets the target roll displacement ITt with respect to the roll of the vehicle to a roll displacement amount corresponding to the horizontal state of the vehicle body 1. , controls the left and right fluid cylinder devices 3.

The acceleration Gs is greater than the predetermined value Gs2, the predetermined value Gs,
For example, if it is 0.5G or less, it is determined that the vehicle is in a comparatively slow turning state, so the target roll displacement! 'rt is a predetermined value T, a larger predetermined value T12, for example 3 mm
(S6, S9>, the suspension characteristic control means controls the fluid cylinder device 3 located on the outside of the turn and the fluid cylinder device 3 located on the inside of the turn, compared to when the vehicle is in a straight-ahead state or a gentle turning state. The difference in hydraulic pressure is further increased to control the attitude of the vehicle body 1 so as to cause it to roll slightly in the opposite direction.

Further, if the acceleration Gs is larger than the predetermined value Gs, it is determined that the vehicle is in a fairly sharp turning state, so the target roll displacement I Ta is set to a predetermined value Tk larger than the predetermined value TR2, for example, 5fflIB. (S6.
5IQ). Therefore, the suspension characteristic control means further increases the difference in hydraulic pressure between the fluid cylinder device 3 located on the outside of the turn and the fluid cylinder device 3 located on the inside of the turn, compared to when the acceleration Gs is 0.5G or less. Then, the attitude of the vehicle body 1 is controlled to further reverse roll.

On the other hand, when the roll mode selection switch 3w is selected to the reverse roll mode (Sl), the lateral acceleration G
s is larger than a predetermined value Gs, for example 0.1G, and less than or equal to a predetermined value Gs, for example 0.3G, and the vehicle speed detection signal V detected by the vehicle speed sensor 19 is a predetermined value V.
8. For example, if it is less than 1201a++/h, the target roll displacement IT certificate is set to ran, for example, 10 mm (34, S5, S7, S8.5it). This target roll displacement amount T14 corresponds to the roll displacement position of the vehicle body 1 in a state where the vehicle height of the portion on the outside of the turn is considerably lower than the vehicle height of the portion on the outside of the turn. , based on the target roll displacement amount T14, the hydraulic pressure difference between the fluid cylinder device 3 located on the outside of the turn and the fluid cylinder device 3 located on the inside of the turn is further expanded than in the normal driving mode, and as a result, the vehicle body 1 The vehicle tilts significantly toward the inside of the turn, resulting in a significant reverse roll condition.

Furthermore, even if the lateral acceleration Gs is greater than the predetermined value Gs, the vehicle speed detection 1 word V is
If it is larger than the predetermined value VI, the driver's sense of security or running stability is more important than the driver's preference, and the target roll displacement amount T is set to the predetermined value T*+s, for example, 0ff.
lfll (S8.512).

Similarly, giving priority to the driver's sense of security over the driver's preference, the suspension characteristic control means controls the acceleration Gs.
is the predetermined value Gs or less (S4), or the predetermined value Gs
If it is larger than 2 (S6), the target roll displacement amount T,
is set to a predetermined value T, (S12), T12 (S9), or T1 in the same way as when the normal driving mode is selected.
Set to 13 (510).

As described above, according to this embodiment, the normal driving mode and the reverse roll mode can be selected by the roll mode selection switch Sw according to the driver's preference or judgment, and when the reverse roll mode is selected, The suspension characteristic control means can set the target roll displacement amount to a large target roll displacement 1TIL4, for example 10 mm, which cannot be set when the normal driving mode is selected. by this,
The driver can select a target roll angle that corresponds to a relatively large reverse roll attitude of the vehicle body 1, and thus can take a vehicle attitude that suits the driver's preference.

Further, in the above embodiment, when the reverse roll mode is selected, predetermined conditions, for example, the vehicle speed sensor 1
9 detects a vehicle speed exceeding a predetermined vehicle speed, for example 120 km/h, or a predetermined lateral acceleration, for example 0.9. If an acceleration less than IG or an acceleration exceeding a predetermined acceleration of 0.3G is detected, the target roll displacement I T t is automatically set as in the normal driving mode even if the reverse roll mode is selected. be done. In this way, when it is desirable to emphasize the driver's sense of security or running stability, the setting of the target roll angle according to the driver's preference is canceled.

The present invention is not limited to the above-mentioned examples, but various modifications can be made within the scope of the invention described in the claims, and these are also included within the scope of the present invention. Needless to say.

For example, in the above embodiment, the lateral acceleration acting on the vehicle body is calculated based on the vehicle steering angle detection signal e and the vehicle speed detection signal.
It may be detected by a lateral acceleration detection sensor.

In addition, in the above embodiment, the target roll displacement amount is set respectively when the normal running mode is selected and when the reverse roll running mode is selected, but the target roll displacement when the normal running mode is selected and the reverse roll mode is selected is It is also possible to incorporate the setting of the displacement amount into a map stored in advance in the control unit in order to set the control gain of each control system.

Table 1 shows an example of a control gain map used in each of the control systems ASBSC and D stored in the control unit 17, and seven modes are set depending on the operating state.

In Table 1, mode 1 is the value of each control gain for 60 seconds after the engine has stopped, and mode 2 is the value of each control gain when the ignition switch is on but the vehicle is stopped and the vehicle speed is zero. The value of the control gain, mode 3, is the value of each control gain when the vehicle's lateral acceleration G is 041 or less and the vehicle is running straight.Mode 4 is the value of each control gain when the vehicle's lateral acceleration G is more than 0.1 and is 043 or less. Mode 5 is the value of each control gain in a slow turning state, and mode 6 is a value of each control gain in a medium turning state where the vehicle's lateral acceleration G is more than 0.3 and less than 0.5. The values of each control gain in a sharp turning state where the directional acceleration Gs exceeds 0.5 are shown respectively. Lateral acceleration Gs is 0.1
When the vehicle speed exceeds 0.3 and the vehicle speed is 1.
When the speed exceeds 20 km/h, the system automatically switches to Mode 4 even if the reverse roll mode is selected. In Table 1, QMA.

represents the maximum flow rate control amount that is fed simultaneously to the proportional flow rate control valve 9 of each wheel, PMAX represents the maximum pressure within the hydraulic pressure chamber 30 of the fluid cylinder device 3, and PMAX represents the maximum pressure within the hydraulic pressure chamber 30 of the fluid cylinder device 3. , is set so that the fluid does not flow back into the akinimulator 22, and PMIN indicates the minimum pressure in the hydraulic pressure chamber 3C of the fluid cylinder device 3, and PMIN indicates the minimum pressure in the hydraulic pressure chamber 3C of the fluid cylinder device 30. The setting is made so that the gas spring 5 will not be damaged due to an excessive decrease in the gas spring 5. In Table 1, the arrow indicates that the control gain is set to the same value as the numerical value indicated by the arrow.

In Table 1, except for mode 7, each control gain is set such that the larger the mode number, the more the suspension control is performed with emphasis on driving stability.

Further, in the above embodiment, the roll mode selection switch 5w is configured to selectively select the reverse roll mode and the normal driving mode, but it is configured such that it can select two or more stages of reverse roll modes. configure or 2
It is also possible to configure the normal driving mode to be selectable in stages or higher.

Effects of the Invention According to the present invention, the driver himself/herself can set the target roll angle of the vehicle when the vehicle turns as desired;
In vehicles equipped with active suspension devices,
It becomes possible to improve the operability of the vehicle by the driver.

[Brief explanation of drawings]

FIG. 1 is an overall schematic diagram of a vehicle including a vehicle suspension device according to an embodiment of the present invention. Fig. 2 is a circuit diagram of a hydraulic circuit that supplies fluid from a hydraulic pump to a fluid cylinder device or discharges fluid from these. Figs. 3A and 3B show suspension characteristic control I in the control unit. 2 is a block diagram of the device. FIG. 4 is a flowchart showing a method for setting the target roll displacement amount shown in FIG. 3A. 1...Vehicle body, 2PL...Left front wheel, 2FR...Left rear wheel,
2RL...right front wheel, 2RR...right front wheel, 3
...Fluid cylinder device, 3FL...Fluid cylinder device for left front wheel, 3FR...
・Fluid cylinder device for right front wheel, 3RL...Fluid cylinder device for left rear wheel, 3RR...Fluid cylinder device for right rear wheel, 3a...Cylinder body, 3b...Piston, 3C・... Hydraulic pressure chamber, 3d... Piston rod, 4... Communication path, 4a, 4b, 4c, 4d... Branch communication path, 5... Gas spring, 5FL... Gas spring for left front wheel , 5FR... Gas spring for the right front wheel, 5RL... Gas spring for the left rear wheel, 5RR... Gas spring for the right rear wheel, 5 a15 b-5cl 5 d"' Gas spring unit, 5e... Diaphragm, 5f... Gas chamber of gas spring, 5g... Hydraulic pressure chamber of gas spring, 8... Hydraulic pump, 8a... Discharge pipe, 9...
...Proportional flow control valve, 9a...Pressure compensation valve, 0,...Fluid passage, 12...Discharge pressure needle, 3
...hydraulic pressure sensor, 14...vehicle height displacement sensor,
5... Vertical acceleration sensor, 7... Control unit, 8... Rudder angle sensor, 19... Vehicle speed sensor, 0
... Drive source, 1... Hydraulic pump for power steering device, 2...
・Accumulator, 3F...Front wheel side piping, 23R...Rear wheel side piping,
3FL...Left front wheel side piping, 3FR...Right front wheel side piping, 3RL...Left rear wheel side piping, 3RR...Right rear wheel side piping, 5as 25b125C% 25d" Orifice, 6
...Switching valve, 8...Unload relief valve, 9...Reserve tank, 3...Opening/closing valve, 34...Solenoid valve, 5.
... Relief valve, 6... Ignition key chain valve, 7... Hydraulic pump relief valve, 8... Return accumulator, 0... Bounce component calculation section, l... Pitch component calculation Parts, 2... Roll line segment calculation unit, 43... Bounce control unit, 44... Pitch control unit, 45... Roll control unit, 46... Differentiator, 47a... Pitch component calculation Parts, 47b...Roll component calculation unit, 48...Pitch control unit, 49...Roll control unit, 50...Bounce component calculation unit, 51...Pitch component calculation unit, 52...Roll Line segment calculation section, 53... Bounce control section, 54... Pitch control section, 55... Roll system! Part 11, 60... Warb control section, 60a... Front wheel side hydraulic pressure ratio calculation section, 60b... Rear wheel side hydraulic pressure ratio calculation section, Sw... Roll mode selection switch.

Claims (1)

[Claims] For each wheel, a fluid cylinder device is provided between the sprung weight and the unsprung weight of the vehicle, and displacement detection means detects the displacement of the vehicle, and the displacement of the vehicle detected by the displacement detection means. suspension characteristic control means for setting and controlling suspension characteristics according to the driving state of the vehicle so as to cancel the displacement of the vehicle based on the above, and controlling the amount of supply and discharge of working fluid to the fluid cylinder device. An active suspension device comprising: a driving mode setting means capable of setting a target roll angle of the vehicle during turning as desired; and a suspension characteristic control means based on the driving mode set by the driving mode setting means. A suspension device for a vehicle, comprising: target roll angle changing means for changing the setting of a target roll angle.