WO1991012973A1

WO1991012973A1 - Device for controlling damping force of vehicle

Info

Publication number: WO1991012973A1
Application number: PCT/JP1991/000222
Authority: WO
Inventors: Hiroshi Ishikawa; Toshiharu Naito; Fumihito Asano
Original assignee: Nippondenso Co., Ltd.
Priority date: 1990-02-26
Filing date: 1991-02-22
Publication date: 1991-09-05

Abstract

Variations in attitude of the vehicle are predicted from acceleration GF in the backward-and-forward direction and that GS in the lateral direction, and vibration conditions of the vehicle are detected on the basis of speed VG of the vehicle above the spring and relative speed VH between members above and below the spring. In response to such variations in attitude and vibration conditions, damping force of the shock absorber is controlled. At this time, as the predicted variation in attitude of the vehicle increases, the degree of variation in damping force dependent on the vibration condition is reduced. In this way, with steering capability kept satisfactory by restricting variations in attitude of the vehicle such as nose-dive and squat, control over the vehicle in consideration of comfort in riding is possible.

Description

Description Vehicle decay control device Technical field

TECHNICAL FIELD The present invention relates to a vehicle damping force control device that controls a damping force of a shock absorber of a vehicle. Background art

In a conventional vehicle damping force control system, the shock absorber was set to a low level during normal driving, and the posture of the squat, dive, roll, etc., changed. The damping force is switched to a higher level when driving.This means that when traveling on a good road such as a paved road, the lower the damping force of the shock absorber, the better the riding comfort. This is because the shock absorber should have a high damping force from the viewpoint of ensuring running stability when the vehicle's posture changes.- The driving conditions under which the above-described posture change occurs When the shock is released, the shock absorber is switched from the high damping force to the low damping force again-and the shock absorber is set to the high damping force according to the judgment of the vehicle driver. Or anything that can be changed to a lower state That (for example, JP 6 0 - 2 3 4 0 1 5 JP).

However, in the conventional vehicle described above, during proper driving, the shock absorbing force of the shock absorber is merely set to a low state, and any aggressive measures are taken to improve the riding comfort. No control is performed. For example, even when driving on a good road, if there are relatively large protrusions and undulations, the vibration of the vehicle increases, so the damping force should be controlled to suppress this vibration. .

Also, when the posture changes, the damping force of the shock absorber is switched to a higher level, so that it may be caused by turning the vehicle in front of the vehicle or lowering its back. The swaying is suppressed and the maneuverability is stabilized, but there is a problem that the ride comfort is not considered at all.

Accordingly, the present invention controls the damping force of the shock absorber in order to improve the ride comfort and the maneuverability, and in particular, emphasizes the ride comfort during normal driving while taking a shot. It controls the damping force of the vehicle and, when the vehicle's attitude changes, controls the damping force related to ride comfort while emphasizing maneuverability. It is an object of the present invention to provide a vehicle damping force control device that can be achieved over the entire operation. Disclosure of the invention

In order to achieve the above object, in a vehicle damping force control device according to the present invention,

A vehicle damping control device that controls the damping force of a shock absorber so as to suppress the vibration of the vehicle and changes in posture.

A shock absorber installed between the vehicle body and the wheels and capable of varying the damping force;

A vibration detecting a vertical vibration state of the vehicle; a dog state detecting means; a posture change detecting means detecting a posture change of the vehicle caused by a driving operation of a driver;

Setting means for setting the damping force of the shock absorber in accordance with these detection results in order to suppress the vibration state of the vehicle or the posture change, and setting the damping force by the setting means to the vehicle. And a catching means for reducing the degree of influence of the vibration state as the change in posture increases.

With this configuration, first, the vertical vibration of the vehicle and the change in the posture of the vehicle due to the driver's driving operation are detected. Here, the vibration state affects the riding comfort of the vehicle, and the change in the posture changes the operation of the vehicle. It affects the verticality. Therefore, by controlling the damping force of the shock absorber in accordance with these detection results in order to suppress the vibration state and posture change, the damping force considering both ride comfort and maneuverability is obtained. You can take control.

In particular, in the present invention, in the above-described damping force control, the influence of the vibration state when setting the damping force is reduced as the change in the attitude of the vehicle increases. For this reason, when the vehicle changes posture, the damping force of the shock absorber is basically set according to this posture change, and the vehicle's maneuverability can be reliably ensured. You. Furthermore, the damping force of the shock absorber is finally set in consideration of the vibration state, so that the control is performed in consideration of the riding comfort of the vehicle while ensuring the maneuverability of the vehicle. Can be performed. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a block diagram showing the configuration of one embodiment of the present invention, FIG. 2 is a block diagram for explaining the operation of the electronic control unit shown in FIG. 1, and FIG. 3 is a block diagram shown in FIG. Fig. 4 is a cross-sectional view of the accumulator shown in Fig. 1, Fig. 5 is a cross-sectional view of the variable throttle valve 7 shown in Fig. 1, and Fig. 6 is an index.

Sprung acceleration due to VG / VH vs. frequency characteristics, Fig. 7 shows the index V _G /

Unsprung acceleration-frequency characteristic diagram by VH, Fig. 8 shows the judgment value of the embodiment shown in Fig. 1 F sprung acceleration-frequency characteristic diagram by F, Fig. 9 shows the judgment value of the embodiment shown in Fig. 1 FIG. 10 is a block diagram for explaining the operation of the second embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to an embodiment shown in the drawings. In this embodiment, a case where the present invention is applied to a strut-type suspension system will be described. FIG. 1 is a configuration diagram of a flat type suspension system showing one embodiment of the present invention. In Fig. 1, the vibration of the oil spring 6 and the coil spring 6 between the vehicle body 1 and the spring member 3 connected to the wheels acts so as to soften the impact from the road surface and not transmit it directly to the vehicle body. A cylinder device as a shock absorber that attenuates is arranged.

Fig. 3 shows a cross-sectional view of this cylinder device. In FIG. 3, the coil spring 6 is disposed between an upper support 33 provided at a lower portion of the vehicle body 1 and a spring receiving member 38 connected to the cylinder 5. The piston 31 is supported by the support 33 and the cushion 32. A piston rod 31 is connected to one end of the piston rod 31, and the piston 31 a is slidably disposed inside the cylinder 5. ing. For this reason, the cylinder 5 is divided into an upper chamber 35 and a lower chamber 34 by the piston 31a. The upper chamber 35 and the lower chamber 34 communicate with each other via a tight connection port 37a provided in the piston 31a. As a result, when the piston 31a force slides inside the cylinder 5, the hydraulic oil flows through the communication port 37a.

Further, a pipe 36 is formed inside the cylinder rod 31. The pipe 36 communicates with the lower chamber 34 via the connection port 37c. It is connected to the upper chamber 35 via the tight port 37b-this pipeline 36 is connected to the accumulator 8 via the variable displacement valve 7 provided in the oil passage 39 Have been. FIG. 4 shows a cross-sectional view of the accumulator 8. In FIG. 4, a left cap 41 is screwed to the left end of the cylinder 40, and a right cap 42 is screwed to the right end. Inside the cylinder 40, a free piston 44 is slidably disposed. For this reason, the interior of the cylinder 40 is partitioned by the free piston 44 into a hydraulic chamber 45a and a gas chamber 45b. The storage angle 43 is fixed to the left end of the cylinder 40 by the left cap 41, and the free piston 44 slides in the direction of the hydraulic chamber 45a. Is regulated. So As a result, hydraulic oil from the cylinder 5 is introduced into the hydraulic chamber 45a through the pipe 36 and the oil path 39, and gas is sealed in the gas chamber 45b. You.

The accumulator 8 stores the hydraulic oil discharged from the upper and lower chambers 34, 35 of the cylinder 5 and operates on the upper and lower chambers 34, 35 of the cylinder 5. It supplies oil. In other words, when the piston 31 a slides inside the cylinder 5, the capacitance in the cylinder 5 changes only by the volume of the piston rod 31 entering and exiting the cylinder 5. I do. When this capacity decreases, the surplus hydraulic oil is discharged to the accumulator 8. On the other hand, when the capacity increases, the insufficient hydraulic oil is supplied from the accumulator 8 to the upper and lower chambers 34, 35.

The accumulator 8 is sealed in the gas chamber 45b when hydraulic oil flows into the hydraulic chamber 45a or hydraulic oil flows out of the hydraulic chamber 4δa. It also functions as a gas spring due to the compression elasticity of the gas. Therefore, it is possible to alleviate the hydraulic shock caused by the opening and closing of the variable throttle valve 7, and also to alleviate the shock at the time when the wheel runs over the protrusion.

A variable throttle valve 7 is provided in an oil passage 39 connecting the accumulator 8 and the upper and lower chambers 34 and 35 of the cylinder 5. The damping force can be varied by adjusting the opening area of the oil passage 39 with the variable throttle valve 7. Fig. 5 shows a cross-sectional view of the variable throttle valve 7.

In FIG. 5, a bush 51 is press-fitted into the right end of the nozzle 50, and the outside of the bush 51 is bolted 5 'through a stopper 52. Screws are tightened. Inside the housing 50, a hollow shaft 54 supported by a bush 51 and a rotor 55 integrated with the shaft 54 are rotatable. It is arranged in. The shaft 54 and the rotor 55 are rotated by the rotating magnetic field generated by the coil 60. Move. Further, in order to take out a wire 61 for supplying a current to the coil 60 to the outside, it is attached to a connector block 63 and a power housing 50 by a screw 64. The connector block 63 is provided with a terminal 62 that is in contact with the wire 61 so that an external current can be supplied. Seal material is injected into the inside 65a and outside 65b of the connector block 63.

A plate 56 is press-fitted into the left end of the nozing, and is fixed with a screw. A bush 57 is press-fitted into the plate 56, and one end of the shaft 54 is rotatably supported by the bush 57. . The plate 56 is provided with a port 59 a communicating with the upper and lower chambers 34 and 35 of the cylinder 5 and a port 59 b communicating with the accumulator 8. The port 59a communicates with the triangular hole 58 and the round hole 67 formed in a part of the shaft 54 through the oil ports 66a and 66b. . On the other hand, the port 59b is connected to the triangular hole 58 and the circular hole 67 formed in the shaft 54 through the hollow portion of the shaft 54. That is, both ports 59a and 59b are in communication with each other through a triangular hole 58 and a circular hole 6-a triangular hole 58 on the side. the outer diameter of the sheet multichemistry is provided partially oice 5 4 contacts the outer member 6 8 outer periphery of the sheet catcher oice 5 4, it ₌ be configured so that by Ru can pivot in a liquid-tight manner On the other hand, the outer diameter of the shaft 54 at the portion where the rounded hole 67 is provided on the side is set smaller than the outer diameter of the portion where the triangular hole 58 is provided at the side. ing. In addition, the oil port 66 a communicating with the port 59 a is formed on a part of the surface of the shaft 54 having a triangular hole 58 on the side surface, and also on the oil port 6 a. 6b is configured to communicate with the surface of a shaft 54 having a round hole 67 on the side surface.

Therefore, when a rotating magnetic field is generated by the coil 60 and the rotor 55 is rotated, the shaft 54 is rotated together with the rotor 55 in the same manner: By changing the position of the triangular hole 58 by the rotation of the shaft 54, the opening area of the hydraulic oil flow path can be adjusted. That is, for example, when the hydraulic oil flows from the port 59a to the port 59b, first, the hydraulic oil flows to the oil ports 66a and 66b. The hydraulic oil flowing into the oil port 66b flows to the surface of the shaft 54 having a circular hole 67 on the side surface. Further, the hydraulic oil flows into the hollow shaft 54 through the circular hole 67 and reaches the port 59b. On the other hand, the oil flowing into the oil port 66a is confined in the hollow shaft 54 from the triangular hole 58 if the triangular hole 58 is in contact with the oil port 66a. Flow to port 59b. However, if the triangular hole 58 is not in contact with the oil port 66a, the hydraulic oil does not flow through the triangular hole 58. In this way, the opening of the variable throttle valve 7 is determined according to the area of the triangular hole 58 opening to the oil port 66a. However, since the circular hole 67 is normally open, even if the triangular hole 58 is fully closed, the hydraulic oil flows to the port 59b little by little.

The vehicle height sensor 4 is disposed between the vehicle body 1 and the unsprung member 3, detects a relative displacement amount between the vehicle body 1 and the unsprung member 3, and outputs it to an electronic control unit (ECU) 9. .

The acceleration sensor 2 is disposed in the lower part of the vehicle body 1, detects the vertical acceleration acting on the vehicle, and outputs the detected acceleration to the EC 9.

The EC unit 9 is a known unit composed of a CPU, a ROM, a RAM, and the like. The EC unit 9 opens the variable throttle valve 7 based on detection signals from the acceleration sensor 2, the vehicle height sensor 4, and other sensor groups. Adjust the degree.

Next, the operation of the ECU 9 in the above configuration will be described.

FIG. 2 is a block diagram illustrating the operation of the ECU 9. In FIG. 2, is a vehicle speed sensor 10 and 11 for detecting the traveling speed of the vehicle, a steering angle sensor for detecting the steering angle of the front wheels, and 12 is a brake switch for detecting whether the brake is on or off. 13 is a slot for detecting the throttle opening. This is a sensor. The ECU 9 receives the detection signals of these sensors and switches and the detection signals of the acceleration sensor 2 and the vehicle height sensor 4 and executes the processing described below.

First, in block 1 0 0, based on a detection signal of the vehicle speed sensor 1 0 and the steering angle Sekusa 1 1 calculates the acceleration G _s in the lateral direction applied to the vehicle body. Since this calculation is known, the description is omitted. In block 1 0 1 determines the absolute value of the lateral acceleration G _s calculated in block 1 0 0 whether squid small Ri goodness predetermined value epsilon i. That is, it is determined whether or not the G acceleration G _s that actually causes the vehicle to change its posture is acting on the vehicle. At this time, if it is determined that the value is smaller than the predetermined value ε i, the flag C is set at block 104! Is set to zero, and if it is determined to be larger, flag Ci is set to '1' in block 102.

In block 1 0 6, based on the detection signal of the blanking Rekisui pitch 1 2 and scan Lock preparative Rousset capacitors 1 3, for computation acceleration G _F in the longitudinal direction applied on the body. Note that this calculation is well-known and will not be described. In block 1 0 7 determines whether squid铯対value small Ri good Tokoro value £ ₂ of the longitudinal acceleration G _F calculated in block 1 0 6 - this and can, Ri yo predetermined value epsilon ₂ if it is determined small the Most set Flag C ₂ in block 1 0 9 to zero and sets "1" to the Flag C ₂ in block 1 0 8 if it is determined to be greater .

In Blocks 125, Flag C! It is determined whether or not C 2 is set to zero. At this time, Flag C! , C 2 are both determined to be zero, it is predicted that the vehicle will not change its attitude, so the opening A! Setting the maximum opening degree A i _m. Meanwhile, since the Flag C i, C 2 when it is determined not to be Gath monitor zero, and the this posture change of the vehicle I by the lateral acceleration G _s or longitudinal acceleration G _F occurs is predicted, The opening Ai according to the vehicle posture change predicted in block 103 is calculated. 215 o That is, first blow Tsu longitudinal computed click 1 0 0 the lateral acceleration G _s and block 1 0 6 calculated in on the basis of the acceleration G _F, and calculates the run line acceleration G _SF according to the following equation.

G s F ⁼ IG s I ten I j FI

Its to determine the attitude opening ASF to cormorants by inversely proportional to the traveling acceleration G _s F of this (proportional constant K.). That is, the larger the traveling acceleration GSF, rather small attitude angle A _S F, the traveling acceleration GSF size rather to set the orientation degree A _{s F} if Kere small. Then, the posture opening A _{s F} and the coefficient K! Set the value obtained by multiplying by the opening A].

A S F = K 0

G s G

1

= Κ 0 (1)

G s:

A = Κ 1 A s: Equation (2)

However, if the opening A, is set to the maximum opening A, _ma _{で in block 126} , then A, = _{Al in a Jt} .

1, 5 block 1 1 0, based on the detection signal G of the acceleration sensor 2, and against the detection signal G of this performed digitally integrating obtain the moving speed V _c of the sprung member _c This sprung speed VG indicates the vibration state of the vehicle body. In addition, in block 111, based on the detection signal H of the vehicle height sensor 4, the detection signal H is digitally differentiated, and the difference between the upper spring member 20 and the lower spring member is determined. Find the relative speed VH.

In block 112, the sprung speed V _G determined in block 110 is divided by the relative speed VH determined in block 111, and the sprung speed V _G is used to calculate the relative speed. The value obtained by multiplying the absolute value of the difference obtained by subtracting VH is calculated as the judgment value F. That is, the judgment value F is

V G

F = X V V H Equation (3)

V H

In the judgment value F, the term VV is the displacement of the unsprung member. It indicates the dynamic speed and corresponds to the vibration state of the wheels. A detailed description of the judgment value F will be described later.

In block 1 1 3, the absolute value of the determination value F obtained in block 1 1 2 is equal to or squid small Ri predetermined value epsilon _3. Yo. This a tree, and small when the yarn is determined, the vibration of the extent to which the driver does not feel, that is, the blanking lock 1 1 4 previous opening at Α ₂ and the current degree of opening Α ₂ and dead zone and all To set. Incidentally, the opening Alpha ₂ is maximum opening A _{2 mex} is set as the initial value. On the other hand, if it is determined to be larger, flag C is set at block 116! , C 2 are both set to zero. Its to, flag C!, Only if it is set to C 2 Gath monitor zero, to set the coefficient K ₂ to 1 in block 1 1 7. Otherwise, block 1 1 in 8 pro-click 1 0 3 obtained traveling acceleration G s coefficient Ri by the Seima-up capturing control attitude control and ride comfort, depending on the value of F K ₂ To determine. This attitude control, in the ride control capturing Seima-up, the value of the running acceleration GS _F number of the engagement of the higher the value Naru is rather large K ₂ must be configured so that by Naru rather small.

In block 1 1 9 determines the sign of the decision value F obtained in block 1 1 2 is positive or negative - in here, sprung velocity V _c is a positive upward, relative velocity VH is The direction of contraction from the neutral position is negative, and the direction of extension is positive = that is, in this block 119, the signs of the sprung speed VG and the relative speed VH match (positive) or do not match (Negative). Then, when the judgment value F is judged to be negative, the opening AF is set to the maximum opening A _{2 m} , * in block 120. On the other hand, if it is determined to be positive, the opening AF according to the absolute value of the determination value F is set by the riding comfort correction map in block # 21. In other words, when the signs match, the damping force is increased to suppress the vibration of the coil spring 6, and when the signs do not match, the damping force is kept low and the vibration is not suppressed.

In block 122, the opening AF set in block 120 or block 121 is added to the opening AF set in block 117 or block 118. The value obtained by multiplying by the coefficient K ₂ obtained in step ₂ is set as the opening Α2. However, if the opening A ₂ in block 1 1 4 is set to the last opening A ₂ opening A ₂ is the previous opening A _2.

That is, the opening A ₂ is

A 2 = K! · A F… (4)

Becomes

In block 1 2 3, out to the block 1 0 opening A i set by the 3 added together pro click 1 2 2 opening A ₂ set in optimally position A force I do. That is, the optimal opening A is

A = A! -A2 ...

And

In block 124, the optimal opening A is converted to a voltage V and output to the variable throttle valve 7, and the voltage V is used to supply a current to the coil 60 of the variable throttle valve 7. Turn on electricity.

When the ECU 9 executes the above-described control, for example, when the cylinder 5 is in the neutral position and the wheel runs on the convex portion, the acceleration sensor 2 and the vehicle height sensor 4 The sign of the judgment value F calculated based on the signals G and H is negative, and the maximum correlation A2 is set as the vibration correlation AF. DOO-out of this, the absolute value, respectively it predetermined value of the lateral acceleration G _s and longitudinal acceleration G _F £ 1, is less than epsilon 2, the variable throttle maximum opening to the valve 7 _A i _m A X eighteen: ^ The voltage corresponding to, is output. With this voltage, a current flows through the coil 60 of the variable throttle valve 7, and the rotor 55 rotates. This maximizes the area where the triangular hole 58 formed in the shaft 54 opens into the oil port 66a. Then, since the throttle of the variable throttle valve 7 is small, the hydraulic oil inside the cylinder 5 is discharged to the accumulator 8 via the variable throttle valve 7 without receiving much resistance. As a result, the cylinder 5 becomes easier to move from the neutral position, and the piston 31 and the coil spring 6 absorb the pushing-up force from below, so that good riding comfort is maintained. On the other hand, for example, when a wheel gets off a convex portion and moves on a flat road surface, tilt may occur. When a tilt occurs, the sign of the judgment value F is switched between positive and negative.However, when the judgment value F is negative, the control is as described above. When is positive, δ will be described.

When the judgment value F is positive, the vibration opening AF according to the absolute value of the judgment value F is set by the ride comfort detection map. This and can, lateral acceleration G _s and the absolute value of each predetermined value epsilon i of the longitudinal acceleration G _F, is less than epsilon _2, the voltage corresponding to the vibration angle A _F is output to the variable Zururi valve 7 '. 0 The voltage causes the rotor 55 of the variable throttle valve 7 to rotate, and the triangular hole 58 opening in the oil port 66 a is adjusted to correspond to the vibration opening _AF . You. Then, since the flow path is restricted by the variable restrictor valve 7, the flow of oil flowing from the accumulator 8 to the inside of the cylinder 5 is suppressed. As a result, the cylinder 5 is harder to move than the neutral position, and the vibration 5 is attenuated.

In Figure 2, the vehicle speed sensor 1 0 and the lateral acceleration G _s being by Ri calculation of the steering angle sensor 1 1 of the detection signal, the brake sweep rate pitch 1 2 and scan Lock Toruse capacitors 1 3 of the detection signal Longitudinal acceleration G _F and force, calculated by the following formula, and the degree of attitude control A! If is set, it works as follows:

In other words, since the running acceleration GSF is large, the opening A! If you are set to have a small opening, the coefficient K ₂ Ri by the control capturing Seima-up attitude control 'ride mind destination is set to a small value. For this reason, even if the vibration opening A _F determined according to the sign of the judgment value F and its magnitude is the maximum opening A _{2 ma} * even if the vibration opening A _F is the maximum opening A _{2 ma} *, the finally determined opening A ₂ Becomes smaller. Therefore, the optimal opening A is set to a small opening that exerts a high damping force.

Here, as described above, the opening degree of the variable throttle valve 7 is The opening A is adjusted to the optimum opening A by adding the opening A related to vibration and the opening A 2 related to vibration. Therefore, each opening A! , A 2 is the maximum opening A! _{When m} and A _{2 x} , the opening degree of the variable throttle valve 7 becomes the maximum. Such a state can be set only when the posture change has not occurred. On the other hand, the lateral acceleration G _s or longitudinal acceleration G _F is detected, when the occurrence of the vehicle attitude change is predicted, position A depending on the posture change is predicted, but the maximum opening degree A i _{m beta chi} Is set to be small. At this time, the opening of the variable throttle valve 7 is A at the maximum. ÷ K 2-A 2 m .x (K 2

<1), and the minimum damping force is increased depending on the attitude change of the vehicle. At the same time, the variable amount of the opening degree of the variable throttle valve 7 based on the determination value F representing the vibration state of the vehicle is reduced, and the influence of the vibration state on the glare control is reduced. Then, within the range of the reduced variable amount, the opening degree に関する₂ relating to the vibration state is determined according to the determination value F in order to suppress the vibration state of the vehicle.

Therefore, according to the present embodiment, the basic damping force is set according to the change in the attitude of the vehicle, and the basic damping force is corrected in a direction to slightly increase the above-described damping force according to the vibration state of the vehicle. You. As a result, it is possible to suppress changes in the vehicle's attitude, such as noise dives and squats, to ensure good maneuverability and to perform control that also takes into consideration riding comfort. And

Next, the determination value F will be described. Judgment value F is suitable as shown in equation (3),

V G

F = X I V G-V H I

V H

It is expressed as

Here, with respect to the judgment value F, the positive / negative judgment is performed based on the term VG / VH which aims at suppressing the vibration of the sprung member. In this positive / negative determination, the determination value F becomes positive when the coil spring 6 vibrates and the cylinder device moves away from the neutral position, and becomes negative when approaching the neutral position. If the judgment value F is positive, the hydraulic oil is Is narrowed. On the other hand, when the determination value F is negative, the opening area of the variable throttle valve 7 is maximized to facilitate the flow of the hydraulic oil. For this reason, the cylinder device is difficult to move from the neutral position, and it is easy to approach the neutral position, so that the cylinder device easily stays at the neutral position.

In the judgment value F, the term IV _G -VHI indicates the unsprung speed, and by including this term in the judgment value F, the judgment increases as the vibration state of the unsprung member increases. The value of the value F increases. Therefore, the vibration of the unsprung member can be suppressed by increasing the damping force as the judgment value F increases.

In here, shows the upper acceleration characteristic diagram ne frequency one field in the case of using the indication that V _c / VH in Figure 6, shows the frequency unsprung acceleration characteristic diagram in Figure 7. In general, the characteristic diagram for judging good riding comfort is the frequency-spring acceleration characteristic graph, and the characteristic for judging good controllability. We will use them here as well.

On the other hand, FIG. 8 shows a frequency-spring-up-spring acceleration characteristic diagram based on the determination value F of the above-described embodiment, and FIG. 9 shows a perimeter-fluid-number-under-sprung-acceleration characteristic diagram. When comparing Fig. 8 with Fig. 8, there is no difference in the maximum value of sprung acceleration. However, when comparing Fig. 7 and Fig. 9, it is clear that the maximum value of the unsprung acceleration is lower for the judgment value F. In other words, if control is performed using the judgment value F, the unsprung acceleration at high frequencies decreases, so that, for example, even when severe vibration is applied to the vehicle body, the vibration is quickly suppressed and the maneuverability is improved. .

Next, a second embodiment of the present invention will be described. In the second embodiment, the control for the change in the attitude of the vehicle is the same as the above-described embodiment, but the control for the vibration state of the vehicle is partially different. Hereinafter, the second embodiment will be described focusing on this difference.

FIG. 10 is a block diagram for explaining the operation of the second embodiment. In the described embodiment, terms i V _c of panel under speed determination value F - was included VHI. In the second embodiment, as shown in blocks 211 and 230, the term V _C / VH for damping the sprung member and the damping of the unsprung member are shown in blocks 21 and 23. The term for the purpose of vibration is separated from VC-VH. This is because the peak of the vibration frequency of the spring member is high (8 to 10 Hz), and if the responsiveness of the variable throttle valve 7 is low, control may not be performed satisfactorily. is there.

First, in block 2 12, a term for damping the sprung member based on the sprung speed VG obtained in block 110 and the relative speed VH obtained in block 11 1. Calculate VG / VH as the judgment value F '. In block 230, the term VG—VH for controlling the vibration of the unsprung member, that is, the unsprung speed, is calculated based on the sprung speed Vc and the relative speed VH.

In block 231, based on the detection signal V of the vehicle speed sensor 10 and the unsprung speed (VG-VH) calculated in block 23, according to the maximum opening setting map, Set the value of the maximum opening A _{2 max} . Here, in the maximum opening setting map, the value of the maximum opening A2 decreases as the vehicle speed detection signal V increases and as the unsprung speed (VC-VH) increases. It is set as follows. Therefore, according to the maximum opening setting map, as the detection signal V of the vehicle speed increases, the value of the maximum opening _A2maχ decreases and the minimum damping force increases, so that the vehicle High-speed stability can be improved. Similarly, as the unsprung speed (Vc-Υ Η) increases, the minimum damping force increases, so that the vibration of the unsprung member can be suppressed, and rough road running performance can be improved. .

On the other hand, in block 2 13, block 2 22 performs the same processing as in the first embodiment using the judgment value F ′ obtained in block 2 12. However, the maximum opening A _{2 ma!} C set as the vibration opening A _F at the _{block 220} is the maximum opening A _{2 mal (} c) determined at the _{block 23} 1. It is set according to the picture value of the judgment value F 'in block 2 21. The maximum opening of the vibration opening A _F is also set as the large opening A _{2 max} determined in block 23 1.

Here, the processing in the blocks 230 and 231 makes the ratio of the number of execution times smaller than the processing of the blocks 221 to 222. As a result, the maximum opening A _{2 m} , _決定 determined by the block 231, changes slowly. Therefore, high-speed response to the vibration frequency of the lower panel member is not required, and the vibration of the lower spring member can be suppressed.

In the above-described embodiment, the variable throttle valve 7 is used in place of the variable throttle valve 7 in a damping force control device that controls the damping force during normal running to be high and the damping force low only when necessary. A stroke-type piezoelectric actuator (actuator using a piezoelectric element) may be used. When using this piezo actuator, the response speed is fast and the flowing current is small.Therefore, the coil spring 6 is used to set the area of the cylinder 5 and the oil pressure at neutral. Therefore, removing coil spring 6 has the same effect as the present invention: = Industrial applicability

As described above, the damping force control device for a vehicle according to the present invention is applicable to a vehicle including a shock absorber that can vary the damping force, and particularly, the damping force is continuously changed. Suitable for vehicles equipped with a shock absorber that can do this.

Claims

The scope of the claims

1. A damping force control device for a vehicle that controls a damping force of a shock absorber so as to suppress a vibration state and a posture change of the vehicle,

A shock absorber that is installed between the vehicle body and the wheels and that can vary the damping force,

A vibration state detecting means for detecting a vertical vibration state of the vehicle, a posture change detecting means for detecting a posture change of the vehicle caused by a driver's driving operation,

Setting means for setting the damping force of the shock absorber based on the vibration state of the vehicle or the change in posture,

A setting means for setting the damping force, wherein the setting means includes a correction means for reducing the degree of influence of the vibration state as the change in the attitude of the vehicle increases.

2. The vibration state detecting means includes:

A sprung speed measuring means for measuring a sprung speed (V 0) of the vehicle, a relative speed measuring means for measuring a relative speed (V H) between the sprung and the unsprung,

Calculating means for performing the following calculation using the sprung speed ( _Vc ) and the relative speed ( _VH ) detected by the sprung speed measuring means and the relative speed measuring means, respectively:

V G / V HI V G-V H I

The vehicle attenuation control device according to claim 1, further comprising: output means for outputting a calculation value obtained by the calculation means as a value indicating a vibration state of the vehicle.

3. The vibration state detection means includes: first vibration detection means for detecting a vibration state of a vehicle on a spring; and second vibration detection means for detecting a vibration state of a vehicle under a spring.

When setting the damping force based on the vibration state of the vehicle, the setting means sets a minimum value of the damping force according to the unsprung state of the vibration under the spring, and sets the minimum value of the damping force. 2. The vehicle damping force control according to claim 1, wherein the damping force is set between a low value and a predetermined maximum damping force value according to a vibration state of the spring.

4. Equipped with traveling speed detecting means for detecting the traveling speed of the vehicle,

5. The vehicle damping device according to claim 3, wherein, as the traveling speed increases, the setting unit captures a minimum value of a damping force set according to the vibration state of the unsprung state. Power control device.

5. The vehicle damping force control device 10 according to claim 1, wherein the shock absorber is capable of continuously changing a damping force.

6. The shock absorber includes a cylinder filled with a working fluid, a piston that divides the interior of the cylinder into two chambers, and a piston that divides the interior of the cylinder into two chambers. An accumulator that is connected to one of the two divided chambers with a fluid path tightly and stores a working fluid; and

15. The vehicle according to claim 5, further comprising an opening control unit that controls an opening of the liquid path to adjust a mobility of the working fluid flowing into and out of the accumulator. 16. Damping force control device

7. A damping force control device for a vehicle that controls the damping of a shock absorber so as to suppress the vibration state and the posture change of the vehicle,

20 A shock absorber that is installed between the vehicle body and the wheels and that can vary the damping force,

25 When the vibration state of the vehicle is detected, if the relative position between the vehicle body and the wheels is in a direction away from the initial state, the attenuation of the shock absorber is increased, and the relative position between the vehicle body and the wheels is increased. If the initial position is in the direction approaching from the initial state, an instruction signal to reduce the damping force of the shock absorber is output. A first means of indicating

Second instruction means for outputting an instruction signal for increasing a damping force of the shock absorber when a change in the attitude of the vehicle is detected;

Setting means for setting the damping force of the shock absorber in response to an instruction signal output from the first and second instruction means;

Correction means for reducing the degree of change in the damping force of the shock absorber by an instruction signal output from the first instruction means as the posture change of the vehicle increases. Power control device.

8. The vibration state detecting means includes:

A sprung speed measuring means for measuring a sprung speed (V G) of the vehicle, a relative speed measuring means for measuring a relative speed (V H) between the sprung and the unsprung,

Calculating means for performing the following calculation using the sprung speed (V _C ) and the relative speed (VH) detected by the sprung speed measuring means and the relative speed measuring means, respectively:

V G / V H · I V G-V Η I

The vehicle damping control apparatus according to claim 7, further comprising: output means for outputting a calculation value obtained by the calculation means as a value indicating a vibration state of the vehicle.

9. The vibration state detection means includes: first vibration detection means for detecting a vibration state of a vehicle on a spring; and second vibration detection means for detecting a vibration state of a vehicle under a spring.

When setting the damping force based on the vibration state of the vehicle, the setting means sets a minimum value of the range attenuation according to the vibration state of the unsprung part, and sets the minimum value of the attenuation power and a predetermined attenuation. 8. The damping force control device for a vehicle according to claim 7, wherein a damping force is set according to a vibration state on the spring between a maximum force value and the vibration value.

10. A cylinder device installed between the vehicle body and the wheels and filled with working fluid, An accumulator for storing the working fluid flowing out of the cylinder device through a liquid passage communicating with the cylinder device;

Adjusting means for adjusting the mobility of the working fluid based on the degree of opening of the liquid path; running detecting means for detecting a running state of the vehicle;

A first method of predicting a change in the attitude of the vehicle based on the running state detected by the running detection means, and setting the opening degree of the liquid path to be smaller as the predicted change in the attitude becomes larger; Setting means;

Vibration detection means for detecting a vibration state of the vehicle,

The degree of opening of the liquid path is set in accordance with the magnitude of the vibration state detected by the vibration detection means, and the vibration changes as the posture change predicted by the first setting means increases. A second setting means for detecting a small opening degree of the liquid path set according to a state;

The opening degree of the liquid path is determined using the opening degree of the channel set by the first setting means and the second setting means, and a signal corresponding to the determined opening degree of the liquid path is determined. Opening degree determining means for outputting;

A damping force control device for a vehicle, comprising: a driving unit that receives the signal from the opening degree determining unit and drives the adjusting unit.

1 1. The vibration state detecting means includes:

A sprung speed measuring means for measuring a sprung speed (Vc) of the vehicle, a relative speed measuring means for measuring a relative speed (VH) between the sprung and the unsprung;

Calculating means for performing the following calculation using the sprung speed (Vc;) and relative speed (VH) detected by the sprung speed measuring means and the relative speed measuring means, respectively;

V G / V H-I V G-V H!

The vehicle damping force control device according to claim 10, further comprising: output means for outputting a calculation value obtained by said calculation means as a value indicating a vibration state of the vehicle.