JP3100775B2 - Vehicle suspension device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension apparatus for a vehicle, which has a flow control valve for controlling the supply and discharge of fluid to and from a cylinder so that suspension characteristics can be changed and a vehicle body attitude is actively controlled. In particular, the present invention relates to an improvement in determination of sticking of a check valve used in the suspension device.

[0002]

2. Description of the Related Art Conventionally, as a vehicle suspension device, for example, as disclosed in Japanese Patent Application Laid-Open No. 3-182826, a fluid cylinder is disposed between a vehicle body and each wheel. A so-called active control suspension device (ACS device) is known, in which the flow rate of the vehicle is independently controlled by a flow control valve for each wheel to vary the suspension characteristics of the vehicle according to the driving state.

FIG. 14 is a diagram schematically illustrating a hydraulic system of a so-called semi-active suspension device. FIG.
, A pump 8 is driven by the rotation of an engine (not shown) to generate a hydraulic pressure. Reference numeral 3 denotes a cylinder having a piston that moves up and down by the fluid to be introduced. The piston moves up and down, thereby varying the distance of the vehicle body to the wheels and controlling the posture of the vehicle body. The amount of fluid to the cylinder 3 is controlled by a flow control valve 9.

[0004] An unload relief valve 28 is connected to the accumulator 22 for accumulating the hydraulic pressure from the hydraulic pump 8, and the oil discharge pressure is set to a predetermined upper limit, for example, 160.
When the pressure is equal to or more than kgf / cm2, the oil is discharged from the hydraulic pump 8 directly to the reserve tank 29. On the other hand, when the oil is equal to or less than a predetermined lower limit, for example, 120 kgf / cm2 or less, the oil is switched to the closed position. Oil is supplied to the accumulator 22.

[0005] The ignition key interlocking valve 36 is
It is connected between the accumulator 22 and the reservoir tank 29, and is opened when the ignition is turned off.
The oil stored in 2 is returned to the reserve tank 29, and the high pressure state in the accumulator 22 is released. The shut-off valve 33 provided between the flow control valve 9 and the cylinder 3 has a hydraulic pressure from the accumulator 22 of a predetermined value (for example, 70 kgf /
cm ² ) or more, the opening state is established, and the flow rate of the fluid to the fluid cylinder device 3 can be controlled by the flow rate control valve 9.

The relief valve 35 opens when the hydraulic pressure in the hydraulic chamber of the fluid cylinder device 3 rises abnormally, and returns the fluid in the hydraulic chamber to the reservoir tank 29. The check valve 91 is connected to the accumulator 2 when the unload valve 28 is opened.
2 is prevented from flowing back into the reservoir tank 29.

[0007]

In such an active suspension system, when the engine is stopped and the driver gets off the vehicle, the vehicle height control is performed to compensate for a change in vehicle height due to a decrease in the weight of the driver. Without any intervention. After the vehicle height correction control, the shutoff valve 33 is closed, and the ignition interlocking valve 3 is closed.
6 is opened to release the pressure of the accumulator 22.

For this reason, if the check valve 91 becomes stuck, the hydraulic pressure in the accumulator 22 flows out through the check valve 91 before the vehicle height correction control is performed after the engine is stopped. When the above-described vehicle height correction control is performed, the main pressure may drop during rest and the vehicle height correction control itself may not be completed. The present invention has been made in view of such a point, and an object of the present invention is to provide a vehicle suspension device that can reliably and early detect the fixation of a check valve provided between a pump and an accumulator. It will not be provided.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a suspension apparatus for a vehicle, in which the suspension characteristics can be changed by controlling the supply and discharge of fluid to and from a cylinder so that the attitude of the vehicle body is actively controlled. And
A pump serving as a discharge source of the fluid, an accumulator for accumulating a discharge fluid from the pump means, and a check valve provided between the pump and the accumulator to prevent backflow from the accumulator to the pump. In an active suspension device for a vehicle, a pressure detecting means for detecting a main pressure indicating a fluid pressure from the accumulator, a stop detecting means for detecting a stop of replenishment of the fluid to the accumulator, and a replenishment of fluid to the accumulator. And determining means for determining whether or not the check valve is fixed based on a change in the main pressure signal from the pressure detecting means after the stop.

[0010]

According to the active suspension device having the above structure, the sticking of the check valve is reflected in the change of the main pressure after the supply of the fluid pressure is stopped, so that the sticking can be determined.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a vehicle having a semi-active suspension device provided with an automatic transmission according to an embodiment of the present invention. <Summary of Embodiment> The active suspension device of this embodiment includes: I: changes in the main pressure immediately after the engine is stopped and changes in the main pressure after a lapse of a predetermined period of time. judge. After stopping the engine,
Since the pump is stopped, the hydraulic pressure is not supplied to the accumulator, so that an abnormal decrease in the main pressure can be immediately judged to be a failure of the check valve. II: If the check valve is not defective, the control for correcting the vehicle height accompanying the decrease in the vehicle weight due to the driver getting off is performed as active suspension control, and then the active suspension control is stopped.

With the above two functions, the abnormality of the check valve can be accurately determined, and the height control after stopping the engine can be performed safely. Hereinafter, examples of the present invention will be further specifically described. <Structure of the transmission system> FIG. 2 shows the structure of the transmission control system of this embodiment.

This transmission control system is provided in an EAT controller 17T, a turbine rotation sensor 102 for detecting the rotation speed of a turbine (not shown) of a torque converter 103 in the automatic transmission 105, and a throttle provided in an intake passage of the engine 100. A throttle opening sensor 105S for detecting the opening of the valve 105, a vehicle speed sensor 19 provided on the output shaft side of the automatic transmission 105 for detecting the vehicle speed,
An inhibitor switch 106 for detecting the position of the select lever 107 for switching the range of the automatic transmission 105, that is, the range of the automatic transmission 105, is provided.

The automatic transmission 105 includes the torque converter 10
3 and a transmission gear mechanism 104 driven by the output of the torque converter 103. As is well known, the transmission gear mechanism 104 is provided with a plurality of friction fastening elements such as a clutch and a brake for switching the power transmission path and a one-way clutch (not shown). , 1, R ranges,
1 to 4 speeds in the D range, 1 to 3 speeds in the 2 range, and 1 to 2 speeds in the 1 range. <Structure of Suspension Apparatus> The suspension apparatus according to the embodiment having such features will be described first with reference to FIG. FIG.
The elements in FIG. 3 that have the same numbers as the elements described in connection with are the same.

FIG. 3 is an overall schematic diagram of a vehicle including a vehicle suspension device according to an embodiment of the present invention. FIG.
1, only the left side of the vehicle body 1 is shown, but the right side of the vehicle body 1 is similarly configured. In FIG. 3, liquid cylinder devices 3, 3 are provided between the vehicle body 1 and the left front wheel 2FL and between the vehicle body 1 and the left rear wheel 2RL, respectively. In the cylinder device 3, a hydraulic chamber 3c is formed by a piston 3b fitted in the cylinder body 3a. The upper end of a piston rod 3d connected to the piston 3b of each fluid cylinder 3 is connected to the vehicle body 1, and each cylinder body 3a is connected to the left front wheel 2FL or the left rear wheel 2FL.
Connected to RL.

The fluid pressure chamber 3c of each fluid cylinder device 3 communicates with a gas spring 5 through a communication passage 4. Each gas spring 5 is connected to a gas chamber 5f and a fluid pressure chamber 5 by a diaphragm 5e.
g, and the hydraulic chamber 5g is in communication with the hydraulic chamber 3c of the fluid cylinder device 3 by the communication passage 4 and the piston 3b of the liquid cylinder device 3. In the fluid passage 10 connecting the hydraulic pump 8 and each fluid cylinder device 3 so as to be able to supply fluid, the flow rate of the fluid supplied to the fluid cylinder device 3 and the flow rate of the fluid discharged from the fluid cylinder device 3 Are provided, respectively.

The hydraulic pump 8 is provided with a discharge pressure gauge 12 for detecting a discharge pressure of a fluid, and a hydraulic pressure sensor 13 for detecting a hydraulic pressure in a hydraulic chamber 3c of each fluid cylinder device 3.
3 are provided. Further, vehicle height displacement sensors 14, 14 for detecting the cylinder stroke amount of each fluid cylinder device 3 and detecting the vertical displacement of the vehicle body with respect to the wheels 2FL, 2RL, that is, vehicle height displacement, are provided. Acceleration in the vertical direction, ie, wheels 2FL, 2FL
Vertical acceleration sensors 15a, 15b, 15c for detecting vertical acceleration on the spring of the RL are provided on a substantially horizontal plane of the vehicle.
The vertical acceleration sensors 15a and 15b are connected to the left and right front wheels 2F.
Above L and 2FL, on the other hand, a vertical acceleration sensor 15c is
A lateral acceleration sensor 16 for detecting lateral acceleration applied in the lateral direction of the vehicle is provided at the center of gravity of the vehicle body 1 at the center of the right and left rear wheels in the width direction of the vehicle. Further, a steering angle sensor 18 and a vehicle speed sensor 19 are provided, respectively.

The discharge pressure gauge 12, the liquid pressure sensors 13, 13, the vehicle height displacement sensors 14, 14, the vertical acceleration sensors 15a, 15b, 15c, and the lateral acceleration sensor 1 provided as described above.
6. The detection signals of the steering angle sensor 18 and the vehicle speed sensor 19 are
Control unit 17S with CPU inside
The control unit 17S performs calculations in accordance with a predetermined program based on these detection signals to control the proportional flow control valves 9 and 9 so as to variably control suspension characteristics as desired. It is configured.

FIG. 4 is a circuit diagram of a hydraulic circuit for supplying a fluid from the hydraulic pump 8 to the fluid cylinder devices 3, 3, 3, and 3, or for discharging a fluid therefrom. In FIG. 4, a hydraulic pump 8 is connected and arranged in parallel with a hydraulic pump 21 for a power steering device driven by a drive source 20, and discharges fluid from the hydraulic pump 21 to the fluid cylinder devices 3, 3, 3, 3. An accumulator 22 is communicatively connected to the discharge pipe 8a, and the discharge pipe 8a is connected to a front-wheel-side pipe 23F at a downstream side of a connection portion of the accumulator 22.
And branches to the rear wheel side pipe 23R. Front wheel side piping 2
3F is branched to the left front wheel side pipe 23FL and the right front wheel side pipe 23FR on the downstream side of the branch portion with the rear wheel side pipe 23R, and the left front wheel side pipe 23FL and the right front wheel side pipe 23FR are respectively for the left front wheel. And the fluid pressure chambers 3c and 3c of the right front wheel fluid cylinder device 3FR. Similarly, the rear wheel side pipe 23R is located downstream of the branch portion,
Branches to the left rear wheel side pipe 23RL and the right rear wheel side pipe 23RR, and the left rear wheel side pipe 23RL and the right rear wheel side pipe 23RR
They are respectively connected to the hydraulic pressure chambers 3c and 3c of the fluid cylinder device 3RL for the left rear wheel and the fluid cylinder device 3RR for the right rear wheel.

The fluid cylinder devices 3FL, 3FR, 3
Gas springs 5FL, 5FR, 5RL and 5RR are connected to RL and 3RR, respectively.
RL and 5RR have four gas spring units 5a, 5b,
5c and 5d.
a, 5b, 5c, and 5d respectively correspond to the hydraulic chambers 3c, 3RL of the corresponding fluid cylinder devices 3FL, 3FR, 3RL, and 3RR.
c, 3c, and 3c, a branch communication passage 4
a, 4b, 4c, and 4d. Further, the branch communication passages 4a, 4a of the gas springs 5FL, 5FR, 5RL, 5RR.
b, 4c and 4d each have an orifice 25
a, 25b, 25c, 25d are provided, and the damping action of these orifices 25a, 25b, 25c, 25d and the buffer action of the gas sealed in the gas chamber 5f of the gas springs 5FL, 5FR, 5RL, 5RR are provided. The reduction of high-frequency vibrations applied to the body is attempted.

Of the gas spring units 5a, 5b, 5c, 5d constituting the gas springs 5FL, 5FR, 5RL, 5RR, the hydraulic chambers 3c, 3c, 3c, 3c of the respective fluid cylinder devices 3FL, 3FR, 3RL and 3RR. In the communication passage 4 provided between the first gas spring unit 5a and the second gas spring unit 5b adjacent to the first gas spring unit 5a, the open position for opening the communication passage 4 and the area of the passage are reduced. By taking the closed position, the passage area of the communication passage 4 is adjusted, and the gas springs 5FL, 5F
A switching valve 26 for switching the damping forces of R, 5RL, and 5RR in two stages is provided. FIG. 4 shows the switching valve 2
6 is shown in the open position.

An unload relief valve is connected to the discharge pipe 8a of the hydraulic pump 8 in the vicinity of the connection portion upstream of the accumulator 22. The unload relief valve 28 measures the oil discharge pressure measured by the discharge pressure gauge 12. When the pressure exceeds a predetermined upper limit, for example, 160 kgf / cm2, the position is switched to the open position, and oil discharged from the hydraulic pump 8 is supplied to the reserve tank 2.
9 directly, while a predetermined lower limit, for example, 120
When the pressure is equal to or less than kgf / cm2, the position is switched to the closed position, oil is supplied to the accumulator 22, and control is performed so that the accumulated pressure value of the hydraulic pressure of the accumulator 22 is maintained at a predetermined value.
Thus, the supply of the oil to each fluid cylinder device 3 is performed by the oil storage of the accumulator 22 maintained at a predetermined pressure value. FIG. 4 shows a state in which the unload relief valve 28 is located at the closed position.

When the suspension device operates, the oil temperature rises. In particular, when the vehicle travels on a rough road, frictional heat is generated when the vehicle passes through each element (in particular, an orifice or the like) in the hydraulic circuit. The electric fan 90 cools the resulting fluid. The electric fan 90 cools the fluid at a position 91 that goes around the hydraulic circuit and returns to the reservoir tank 29. The oil temperature T is measured by an oil temperature sensor 92.

Here, the hydraulic circuits of the left front wheel, the right front wheel, the left rear wheel and the right rear wheel are configured in the same manner, so that only the hydraulic circuit of the left front wheel will be described below. This is omitted. The proportional flow control valve 9 is formed of a three-way valve, and has a closed position for closing all ports, a supply position for opening the left front wheel side pipe 23FL to the hydraulic pressure supply side, and a left front wheel side pipe 2
The 3FL fluid cylinder device 3 can be set at three positions, that is, a discharge position communicating with the return pipe 32. FIG. 4 shows a state where the proportional flow control valve 9 is located at the closed position. Further, the proportional flow control valve 9 includes pressure compensating valves 9a, 9a.
a, 9a, when the proportional flow control valve 9 is at the supply position or the discharge position, the hydraulic pressure chamber 3c of the fluid cylinder device 3
The internal fluid pressure is maintained at a predetermined value.

On the fluid cylinder device 3 side of the proportional flow control valve 9, a pilot pressure-responsive shut-off valve 33 capable of opening and closing the left front wheel side pipe 23FL is provided. This shutoff valve 33
The hydraulic pressure of the solenoid valve 34 is introduced as a pilot pressure when the solenoid valve 34 for guiding the hydraulic pressure of the left front wheel side pipe 23FL on the hydraulic pump 8 side of the proportional flow control valve 9 is introduced as a pilot pressure. For example, when the pressure is 70 kgf / cm ² ) or more, the shutoff valve 33 opens the left front wheel side pipe 23FL and the proportional flow control valve 9
, The flow rate of the fluid to the fluid cylinder device 3 can be controlled.

Further, the hydraulic chamber 3c of the fluid cylinder device 3
Is opened when the hydraulic pressure in the chamber rises abnormally, and is connected to a relief valve 35 for returning the fluid in the hydraulic chamber 3 c to the return pipe 32, a discharge pipe 8 a of the hydraulic pump 8 near the downstream side of the connection part of the accumulator 22, Opened when the ignition is off, the oil stored in the accumulator 22 is stored in the reserve tank 2
9, the oil in the hydraulic pump 8 is returned to the reserve tank 29 when the oil discharge pressure of the ignition key interlocking valve 36 and the hydraulic pump 8 for releasing the high pressure state in the accumulator 22 is abnormally increased. 8, a return accumulator 38 which is connected to a hydraulic pump relief valve 37 for lowering the oil discharge pressure and a return pipe 32 and performs a pressure accumulating action when the fluid is discharged from the fluid cylinder device 3.
38 are provided respectively. <Fluid control amount calculation> FIGS. 5 to 12 are block diagrams of a fluid control amount calculation device provided in the control unit 17S.

Referring to FIGS. 5 to 12, the liquid control amount calculating device provided in the control unit 17S according to the present embodiment includes a vehicle height displacement signal XFR, XFR, of vehicle height sensors 14, 14, 14 and 14 of each vehicle. A control system A for controlling the vehicle height to a target vehicle height based on XFL, XRR, XRL, and vehicle height displacement speed signals YFR, YFL, YRR obtained by differentiating the vehicle height displacement signals XFR, XFL, XRR, XRL. And a control system B for suppressing the vehicle height displacement speed on the basis of YRL and vertical acceleration signals GFR, GFR of three vertical acceleration sensors 15a, 15b and 15c.
A control system C for reducing the vertical vibration of the vehicle based on GFL and GR, and hydraulic pressure sensors 13, 13, 13,
13 based on the pressure signals PFR, PFL, PRR, and PRL, and a control system D for suppressing the torsion of the vehicle body, and a lateral acceleration detection signal GL of the lateral acceleration sensor 16 for detecting the vehicle torsion. It comprises a control system E for reducing vibration.

The control system A includes a vehicle height sensor 14 for each wheel,
14, 14, 14, the vehicle height displacement signal XFR,
Low-pass filters 40a, 40b, 40 that cut high-frequency components in order to cut noise of XFL, XRR, XRL
c, 40d are provided, and the low-pass filters 40a, 40d are provided.
b, left and right front wheels 2FL with high frequency components cut off,
The outputs XFR and XRL of the 2FR vehicle height sensors 14 and 14 are added, and the outputs XRR and XRL of the left and right rear wheel 2RL and 2RR vehicle height sensors 14 and 14 from which high-frequency components have been cut by the low-pass filters 40c and 40d. Bounce component calculation unit 41 that calculates the bounce component of the vehicle by adding
Output X of vehicle height sensors 14, 14 of left and right front wheels 2FL, 2FR
The sum of the outputs XRR and XRL of the vehicle height sensors 14 and 14 of the left and right rear wheels 2RL and 2RR is subtracted from the sum of FR and XFL.
A pitch component calculation unit 42 for calculating a pitch component of the vehicle, outputs XR of the vehicle height sensors 14, 14 of the left and right front wheels 2FL, 2FR.
The difference XFR-XFL between R and XFL and the difference RR-XRL between the outputs XRR and XRL of the vehicle height sensors 14 and 14 of the left and right rear wheels 2RL and 2RR.
And a roll component calculation unit 43 that calculates the roll component of the vehicle by adding

The control system A includes a bounce component calculation unit 4
The bounce control unit 44, which receives the vehicle bounce component calculated in step 1 and the target average vehicle height TH, calculates the amount of fluid supplied to the fluid cylinder device 3 of each wheel in the bounce control based on the gain KB1, a pitch component The pitch component of the vehicle calculated by the calculation unit 42 is input, and the pitch control unit 45 and the roll component calculation unit 43 that calculate the fluid supply amount of each wheel to the fluid cylinder device 3 in the pitch control based on the gain KP1. The calculated roll component and the target roll displacement TR are input, and gains KRF1 and KRR1 are input.
Is provided with a roll control unit 46 for calculating the amount of fluid supply to the fluid cylinder device 3 of each wheel in roll control so that the vehicle height corresponds to the target roll displacement TR.

The control amounts calculated by the bounce control unit 44, the pitch control unit 45, and the roll control unit 46 are inverted for each wheel, that is, the vehicle height sensors 14, 14, 14, The vehicle height displacement signals XFR, XFL, XRR, and XRL detected at 14 are inverted so that their signs are opposite, and thereafter, control amounts of bounce, pitch, and roll for each wheel are added, respectively. ,
Control flow signals QFR1, QFL1, QRR1, QRL1 to the proportional flow control valve 9 of each wheel in the control system A are obtained.

Here, each low-pass filter 40a, 40
b, 40c, 40d and the bounce operation unit 41, the pitch operation unit 42, and the roll operation unit 43,
7a, 47b, 47c, 47d are provided, and vehicle height displacement signals XFR, XFL, XRR, XRL inputted from the vehicle height sensors 14, 14, 14, 14 via low-pass filters 40a, 40b, 40c, 40d. , These vehicle height displacement signals XFR, XFL, XRR, and XRL are obtained only when the vehicle exceeds a preset dead zone XH, XH, XH, XH.
The data is output to the bounce calculation unit 41, the pitch calculation unit 42, and the roll calculation unit 43.

The control system B includes vehicle height sensors 14, 14, 1
4 and 14 and a low-pass filter 40
a, 40b, 40c, and 40d, the high-frequency components are cut off, and the vehicle height displacement signals XFR, XFL, XRR, and XRL are differentiated.
According to the following equation, the vehicle high displacement speed signals YFR, YFL, YR
Differentiators 50a, 50b, 50c, 5 for calculating R and YRL
0d.

Y = (Xn-Xn-1) / T where Xn is the vehicle height displacement at time t and Xn-1 is the time t-
The vehicle height displacement amount of 1 and T is a sampling time. Further, the control system B obtains the left and right rear wheels 2RL, 2RR from the sum of the vehicle high displacement speed signals YFL, YFR on the left and right front wheels 2FL, 2FR.
Subtracting the sum of the vehicle high displacement speed signals YRL and YRR
A pitch component calculating section 51 for calculating a pitch component of the vehicle; and a vehicle high displacement speed signal YF on the left and right front wheels 2FL and 2FR.
A roll component calculator 52 that adds the difference YFR-YFL between L and YFR and the difference YRR-YRL between the vehicle high displacement speed signals YRL and YRR on the left and right rear wheels 2RL and 2RR to calculate the roll component of the vehicle. And

The pitch component thus calculated by the pitch component calculator 51 is input to the pitch controller 53, and the flow control amount to each proportional flow control valve 9 in the pitch control is calculated based on the gain KP2. The roll component calculated by the roll component calculation unit 52 is input to the roll control unit 54, and based on the gains KRF2 and KRR2, the roll component is adjusted to a vehicle height corresponding to the target roll displacement TR. A flow control amount to each proportional flow control valve 9 in the control is calculated.

The pitch control unit 53 and the roll control unit 54
The positive and negative of the control amounts calculated by are further inverted for each wheel, that is, the differentiators 50a, 50b, 50
c, 50d, the vehicle high displacement speed signals YFR, Y
FL, YRR, and YRL are inverted so that the positive and negative are opposite. Thereafter, the respective control amounts of the pitch and roll for each wheel are added, respectively, to the proportional flow control valve 9 of each wheel in the control system B. Flow signals QFR2, QFL2, QRR
2, QRL2 is obtained.

The control system C includes low-pass filters 60a, 60
0b, 60c, a bounce component calculator 61 for adding the vertical acceleration detection signals GFR, GFL, GR detected by the vertical acceleration sensors 15a, 15b, and 15c from which high-frequency components have been cut, and calculating a bounce component of the vehicle; Sum (GFR + GFL) of 1/2 of the output of the vertical acceleration sensors 15a, 15b mounted above the left and right front wheels 2FR, 2FL /
2, a pitch component calculator 62 for calculating the pitch component of the vehicle by subtracting the output GR of the vertical acceleration sensor 15c provided at the center of the left and right rear wheels in the vehicle width direction, and a vertical acceleration sensor for the right front wheel. A roll component calculator 63 is provided for calculating the roll component of the vehicle by subtracting the output GFL of the vertical acceleration sensor 15b on the left front wheel side from the output GFR of 15a. The bounce component calculated by the bounce component calculation unit 61 is input to the bounce gain correction unit 91, and the pitch component calculated by the pitch component calculation unit 62 is input to the pitch gain correction unit 92, and the roll component calculation unit The roll component calculated by 63 is output to the roll gain correction unit 93. Bounce gain correction unit 91,
Pitch gain corrector 92 and roll gain corrector 93
Includes a detection signal of the vehicle speed V detected by the vehicle speed sensor 19, a detection signal of the steering angle θ detected by the steering angle sensor 18, and the vertical accelerations GFR, GFL, GR detected by the three vertical acceleration sensors 15a, 15b, 15c. The bounce gain corrector 91, the pitch gain corrector 92, and the roll gain corrector 93 are respectively input to the bounce component, the pitch component, the positive or negative of the roll component, the vehicle speed V, and the steering angle θ.
Based on the vertical accelerations GFR, GFL, and FR, a control gain correction signal is generated in accordance with a correction map which is experimentally determined in advance and stored.

Further, the control system C includes a bounce control unit 64 to which the calculated value of the bounce component calculated by the bounce component calculation unit 61 and the control gain correction signal generated by the bounce gain correction unit 91 are input, and a pitch component A pitch control unit 65 to which the calculated value of the pitch component calculated by the calculation unit 62 and the control gain correction signal generated by the pitch gain correction unit 92 are input, and a calculated value of the roll component calculated by the roll component calculation unit 63 And a roll control unit 66 to which the control gain correction signal generated by the roll gain correction unit 93 is input. The bounce control unit 64 is configured to output the control gain correction signal based on the control gain correction signal input from the bounce gain correction unit 91. The gain KB30 stored in advance is corrected, the gain KB3 is calculated, and the performance of the pitch component is calculated. Based on the value and the calculated gain KB3, the control amount of the fluid to each of the proportional flow control valves 9 in the bounce control is calculated, and the pitch control unit 65 outputs the control gain correction signal input from the pitch gain correction unit 92 to the control gain correction signal. Based on the calculated gain KP3, the gain KP3 stored in advance is corrected to calculate the gain KP3. Based on the calculated value of the pitch component and the calculated gain KP3, the control amount of the fluid to the proportional flow control valve 9 in the pitch control is calculated. Then, the roll control unit 66 corrects the gains KFR30 and KRR30 stored in advance based on the control gain correction signal input from the roll gain correction unit 93, and obtains the gains KFR3 and KRR3.
And the calculated value of the roll component and the calculated gain K
The control amount of the fluid to the proportional flow control valve 9 in the roll control is calculated based on FR3 and KRR3.

The control amount calculated and calculated by the bounce control unit 64, the pitch control unit 65, and the roll control unit 66 is inverted for each wheel, and thereafter, the bounce, pitch, And the control amounts of the rolls are added, and the flow signals QFR3, QFL3, QRR3 and QRL output from the control system C to the proportional control valves 9 are output.
3 is obtained.

The low-pass filters 60a, 60b and 60c for cutting high-frequency components, the bounce component calculator 61, the pitch component calculator 62 and the roll component calculator 63
And between the dead zones 67a, 67b, 67, respectively.
c are provided, and the vertical acceleration sensors 15a, 15
b, 15c, the low-pass filters 60a, 60b, 6
0c, 60d, and the vertical acceleration signal GFR,
GFL, GR are preset dead zones XG, XG
, XG, these vertical acceleration signals GFR, GFL, FR are output to the bounce component calculator 61, the pitch component calculator 62, and the roll component calculator 63.

The control system D receives the hydraulic pressure detection signals PFL and PFR detected by the hydraulic pressure sensors 13 and 13 of the fluid cylinder devices 3 of the left and right front wheels 2FL and 2FR, and the high-frequency components thereof are converted into low-pass filters 70a and 70a. 70b, the fluid cylinder device 3 of the left and right front wheels 2FR and 2FL after being cut.
Of the hydraulic pressure of the hydraulic pressure chambers 3c, 3c, PFR-PFL, and the sum of the added value PFR + PFL, Pf = (PFR-PFL) / (PFR
+ PFL), and when the calculated hydraulic pressure ratio Pf satisfies −ωL <Pf <ωL with respect to the threshold hydraulic pressure ratio ωL, the calculated hydraulic pressure ratio Pf is output as it is.
If f <−ωL or Pf> ωL, the front-wheel-side hydraulic-pressure-ratio calculator 71a that outputs the threshold hydraulic pressure ratio −ωL or ωL, and similarly, the liquid cylinder device 3 of the left and right front wheels 2RL and 2RR. The hydraulic pressure detection signals PRL and PRR detected by the hydraulic pressure sensors 13 and 13 are input, and the high-frequency components thereof are cut by the low-pass filters 70c and 70d, and then the fluid cylinder devices 3 of the left and right front wheels 2FR and 2FL are cut.
And a rear wheel side hydraulic pressure ratio calculating unit 71b for calculating the ratio Pr of the hydraulic pressure difference PRR-PRL between the hydraulic pressure chambers 3c and 3c and the added value PRR + PRL, Pr = (PRR-PRL) / (PRR + PRL). A warp control unit 71 that multiplies the rear wheel side hydraulic pressure ratio Pr by a predetermined value based on the gain ωF and then subtracts this from the front wheel side hydraulic pressure ratio Pf. The output is multiplied by a predetermined value by using the gain ωA, and thereafter, the output is multiplied by a predetermined value by using the gain ωc on the front wheel side. Further, the fluid supply control amount to each wheel is opposite between the left and right wheels. The flow signals QFR4, QFL4, QRR4, QRL4 to each proportional flow control valve 9 in the control system D are obtained.

Further, the control system E includes a lateral acceleration sensor 16
The lateral acceleration detection signal applied in the lateral direction of the vehicle detected by the above is input, and after its high-frequency component is cut by the low-pass filter 80, the control amount is calculated based on the gain Kg, and the left and right front wheels 2FL, 2FR Is further multiplied by a predetermined value based on the gain AGF, and thereafter, the liquid supply control amount of the left front wheel 2FL is reversed so that the fluid supply control amounts to the left and right wheels are opposite in sign. For the left and right front wheels 2RL, 2RR, the fluid supply control amounts of the left rear wheel 2FL are reversed so that the positive and negative fluid supply control amounts to the left and right wheels are reversed. Flow rate signals QFR5, Q to control valve 9
FL5, QRR5 and QRL5 are obtained.

Each of the control systems A,
The flow signals to the respective proportional flow control valves 9 in B, C, C and E are added for each wheel, and are further added to the left and right front wheels 2.
FL and 2FR are multiplied by a gain AF, left and right rear wheels 2RL and 2RR are multiplied by a gain AR, and total flow signals QFR, QFL, QRR, QRR of each proportional flow control valve 9a are multiplied.
RL is obtained. <Detection of Stuck Check Valve 91> Next, check valve 91
A method for determining the sticking of the image will be described with reference to FIGS.

FIG. 1 shows a part of the active suspension control system shown in FIG. 4, which is particularly related to the operation of the part related to the embodiment according to the present invention. The controller 17S is a controller for controlling the active suspension described above.
Also, it has a function of detecting the sticking of No. 1. The alarm 103 informs the driver that the check valve 91 has become stuck.

The controller 17S monitors the change of the on / off state of the ignition switch 101. In this embodiment, the pump 8 of the type driven by the engine is employed as long as the ignition is turned on.
It is confirmed that the pump 8 is stopped and no more hydraulic pressure is supplied to the accumulator 22. The controller 17S also keeps the ignition interlocking valve 336 closed. This is because when the interlocking valve 36 is opened, all the pressure in the accumulator 22 is released.

In this state, the main pressure P is monitored for a predetermined time after the pump stops. If the main pressure has not fallen below the predetermined value, it is determined that the check valve 91 is normal, and thereafter, the vehicle height correction control is executed. Hereinafter, FIG.
The operation of the embodiment will be described with reference to the flowchart of FIG. In step S2, the process waits until the ignition is turned off. In step S4, the active suspension control is stopped in response to the ignition being turned off.
This stop is for accurately measuring the main pressure P in a state where the active suspension for correcting the vehicle height is performed in step S18 but the active suspension is not performed. In this case, as described with reference to FIG. 1, the ignition interlocking valve 36 is also kept off.

In step S6, the main pressure P ₀ is monitored by the sensor 12. In step S8, the process waits for a predetermined time to elapse. Although this predetermined time varies depending on the vehicle type,
It can be measured experimentally in advance for each vehicle type. In step S10, measuring the further main pressure P ₁ after a predetermined time after engine stop. In step S12, the absolute value of the difference between the main pressure P ₀ and P _1, which is measured is determined whether or not it is greater than a predetermined value [delta].

If | P ₀ −P ₁ | ≧ δ, the check valve 91 is determined to be defective (step S14).
If | P ₀ −P ₁ | <δ, it is determined to be normal. Such a reference value δ is stored in the memory 1
02 is stored.

If it is determined that there is a stick, step S16
The fact that such fixation has occurred is stored in the memory 102. Specifically, an alarm is issued to the alarm 103.
Then, in step S36, the interlocking valve 36 is opened to release the pressure in the accumulator 22, and in step S2
At 6, the shut-off valve 33 is closed. If it is determined in step S12 that the check valve 91 is normal, the active suspension control is restarted in step S18. That is, the vehicle height correction is thereby performed. It is this vehicle height correction elapses a predetermined time at step S20, the main pressure is continued until either reduced to a predetermined value P ₃ in step S22. Step S
This is because the vehicle height correction of 18 is performed while the pump 8 is stopped, so that the main pressure gradually decreases.
In other words, have the vehicle height correction for a predetermined time in step S20 is expected to be completed, nevertheless, since the main pressure is no sense to perform the vehicle height correction when dropped below P ₃ It stops.

In step S24, the active suspension control for correcting the vehicle height is stopped.

[0050]

As described above, according to the present invention, there is provided a suspension apparatus for a vehicle which actively controls a vehicle body posture by changing a suspension characteristic by controlling supply and discharge of a fluid to and from a cylinder. A vehicle having a pump serving as a fluid discharge source, an accumulator for accumulating a discharge fluid from the pump means, and a check valve provided between the pump and the accumulator for preventing backflow from the accumulator to the pump. The active suspension device includes a pressure detecting unit that detects a main pressure indicating a fluid pressure from the accumulator, a stop detecting unit that detects a stop of replenishment of the fluid to the accumulator, and a stop of replenishment of the fluid to the accumulator. Later, based on the change of the main pressure signal from the pressure detection means, the check valve Characterized by comprising a determination means for determining wear.

According to the active suspension device having the above structure, the sticking of the check valve is reflected in the change of the main pressure after the supply of the fluid pressure is stopped, so that the sticking can be determined. Therefore, it is possible to reliably determine whether the check valve is stuck. According to the preferred embodiment, after it is determined that the check valve is normal, the required vehicle height attitude control is safely performed when the driver gets off the vehicle.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an operation principle of an embodiment.

FIG. 2 is a block diagram of a control system for a transmission of a vehicle to which the present invention is applied.

FIG. 3 is a block diagram of an active suspension device for a vehicle to which the present invention is applied.

FIG. 4 is a circuit diagram of a hydraulic circuit of the active suspension device.

FIG. 5 is a view for explaining logic for calculating a flow rate.

FIG. 6 is a diagram illustrating logic for calculating a flow rate.

FIG. 7 is a diagram illustrating logic for calculating a flow rate.

FIG. 8 is a diagram illustrating logic for calculating a flow rate.

FIG. 9 is a diagram illustrating logic for calculating a flow rate.

FIG. 10 is a diagram illustrating logic for calculating a flow rate.

FIG. 11 is a diagram illustrating logic for calculating a flow rate.

FIG. 12 is a diagram illustrating logic for calculating a flow rate.

FIG. 13 is a flowchart illustrating a control procedure for detecting check valve sticking according to the embodiment.

FIG. 14 is a diagram illustrating a conventional problem.

[Explanation of symbols]

9: Flow control valve, 12: Fluid pressure sensor, 15: Vertical G sensor, 17S: Controller, 33: Shut-off valve, 36: Ignition interlocking valve, 91: Check valve, 100: Timer, 101: Ignition key, 102: Memory (R
AM), 103 ... alarm

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60G 17/015 B60G 17/056

Claims (5)

(57) [Claims] 1. A suspension device for a vehicle which actively controls a vehicle body posture by changing a suspension characteristic by controlling a supply and discharge of a fluid to and from a cylinder.
A pump serving as a discharge source of the fluid, an accumulator for accumulating a discharge fluid from the pump means, and a check valve provided between the pump and the accumulator to prevent backflow from the accumulator to the pump. In the active suspension device for a vehicle, a pressure detection unit that detects a main pressure indicating a fluid pressure from the accumulator, a stop detection unit that detects a stop of the supply of the fluid to the accumulator, and a supply of the fluid to the accumulator. A suspension device for a vehicle, comprising: a determination unit that determines, after stopping, the fixation of the check valve based on a change in the main pressure signal from the pressure detection unit. 2. The vehicle suspension device according to claim 1, wherein said stop detecting means detects a stop of the pump due to an engine stop. 3. The vehicle suspension device according to claim 1, wherein said determining means makes a determination based on a change in a main pressure during a predetermined time after the supply of fluid to said accumulator is stopped. apparatus. 4. The vehicle suspension device according to claim 2, wherein the vehicle height control is performed when the main pressure after the predetermined time is within a predetermined value. 5. The suspension system for a vehicle according to claim 1, wherein the determination means stores in advance data indicating a change in a reference main pressure, and compares the reference pressure data with a detected change in the main pressure. A suspension device for a vehicle, comprising: