JPH0840034A - Damping force control device of vehicle - Google Patents

Abstract

PURPOSE:To optimally control rolling, pitching and flapping by disturbance of a road surface by detecting vertical directional vibrations of horizontal directional two positions, controlling a damping force changing mechanism when the vibrations become large, and changing control sensitivity of a damping force control means by the correlation between both detecting values. CONSTITUTION:Damping force of shock absorbers 10A to 10D arranged between a lower arm and a car body is switched in two stages of hard and soft by switching opening of valves 14a to 14d. Detecting signals of vertical acceleration sensors 21 and 22 arranged on the car body in the vicinity of left and right front wheels are inputted to a microcomputer 25 through band-pass filters 23 and 24, and damping force is controlled by driving the valves 14a to 14d through driving circuits 26a to 26d. The vertical acceleration sensors 21 and 22 judge that in which detected vibration is put among the in-phase and antiphase relationships, and changes control sensitivity of the damping force according to this. Therefore, optimal damping force control fitted for an occupant can be performed on flapping, pitching and rolling of the car body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle damping force control device for controlling a damping force changing mechanism which is provided between a wheel and a vehicle body and is capable of changing the damping force with respect to vertical movement of the vehicle body.

[0002]

2. Description of the Related Art Conventionally, an apparatus of this type is disclosed in, for example, Japanese Patent Laid-Open No.
As disclosed in Japanese Patent Application Laid-Open No. 9-227515, a vibration sensor for detecting the vibration of the vehicle body is attached to the vehicle body, and when the vibration level of the vehicle body detected by the sensor exceeds a predetermined threshold value, a damping force changing mechanism. Is controlled to set a large damping force for the vibration of the vehicle body to suppress the rolling of the vehicle body.

[0003]

Vibrations of the vehicle body include vertical movements of the vehicle body, that is, "orbits" and "rolls and pitches" of the vehicle body due to road surface disturbances, which are related to the resonance frequency of the vehicle body (sprung member). However, since both of these vibration frequencies are in the frequency range of about 1 to 2 Hz, it is difficult to detect them separately. On the other hand, the vibration level of the "roll and pitch" is smaller than the vibration level of "orientation", and the occupant feels the "roll and pitch" more sensitively than "orientation". Therefore, in order to optimally suppress the roll of the vehicle body as in the conventional device, it is necessary to set the reference value small, that is, set the control sensitivity high. However, in this case, when the vehicle tilts, the damping force is frequently switched to the larger side, so that the riding comfort of the vehicle is not good. On the contrary, if the threshold value is set to a large value, optimal damping force control is achieved for the vehicle body "tilt", but necessary damping force control is performed for the vehicle body "roll and pitch". More often not. The present invention has been made to solve the above problems, and an object thereof is to optimally control a damping force both for "roll or pitch" due to road surface disturbance of a vehicle body and for "body tilt". Another object of the present invention is to provide a vehicle damping force control device.

[0004]

In order to achieve the above-mentioned object, a common and basic feature of the present invention is that at least two parts of a vehicle body whose horizontal positions are different are vertically arranged. A first vibration sensor and a second vibration sensor for respectively detecting the vibration of the vehicle body are provided, and the "orbit" of the vehicle body and the "pitch or roll" due to the road surface disturbance are separately detected by the vibrations of these two portions of the vehicle body, and these The purpose is to be able to individually suppress the vibrations of the two types of vehicle bodies. In order to separately detect the vibration type of the vehicle body, in the present invention, the phases of the vibrations of the respective parts of the vehicle body are substantially the same, that is, the same phase in the case of the "orientation" of the vehicle body, and in the case of the "pitch or roll" of the vehicle body. The phenomenon is utilized by paying attention to the phenomenon that the phases of the vibrations of each part of the vehicle body are different, that is, opposite phases. Therefore,
In the following structural features of the present invention, “in-phase” means not only that the phases of the vibrations of the vehicle body parts are in true agreement, but also that the phase difference between the vibrations is small within the range of 2π, In addition, "reverse phase" means that the same phase difference is large within the range of 2π.

A first feature of the configuration of the present invention is to judge whether each of the vibrations detected by the first and second vibration sensors has the in-phase relation or the anti-phase relation,
The control sensitivity of the damping force with respect to the vertical movement of the vehicle body is changed according to the determination result. According to this,
The control sensitivity of the damping force with respect to the vertical movement of the vehicle body is changed by the "orientation" of the vehicle body and the "roll or pitch" due to road surface disturbance. Therefore, it is possible to perform the optimum damping force control suitable for the occupant by the "orientation" and the "pitch or roll" of the vehicle body.

A second feature is that the damping force is increased on condition that the vibration level of the vehicle body is larger than the first threshold value when it is determined that the respective vibrations are in phase.
The damping force is increased on the condition that the vibration level of the vehicle body is larger than the second threshold value smaller than the first threshold value when it is determined that the respective vibrations are in the opposite phase. According to this, if the vibration of the vehicle body is related to "flapping", the damping force cannot be switched to the larger side unless the vibration is considerably large. On the other hand, if the vibration of the vehicle body is related to "pitch or roll" due to road surface disturbance, the damping force can be switched to the larger side even if the vibration does not become too large. These things are also compatible with the general physical characteristics that the vibration level of the "pitch and roll" of the vehicle body is smaller than the vibration level of "aori", and the occupant changes the "pitch and roll" to "aori". It is also suitable for the sensory characteristic of being more sensitive, so that the optimum damping force control is performed both physically and sensibly.

The third characteristic is the same as the second characteristic.
Further, a vehicle speed sensor is provided to detect the vehicle speed, and the first threshold value that changes according to the vehicle speed is determined based on the detected vehicle speed. According to this, the vibration level of the vehicle body related to the "flapping" of the vehicle body that is switched to the side with the larger damping force is determined depending on the vehicle speed. Therefore, as the vehicle speed increases, the "force" of the vehicle body decreases due to downforce, and the sensational characteristic that the occupant becomes less sensitive to the "motion" as the vehicle speed increases. Since the control can be adapted, the damping force control can be further optimized.

The fourth characteristic is the same as the second characteristic.
Further, a vehicle speed sensor is provided to detect the vehicle speed, and the second threshold value that changes according to the vehicle speed is determined based on the detected vehicle speed. According to this, the vibration level of the vehicle body related to the "pitch or roll" of the vehicle body due to the road surface disturbance that is switched to the side where the damping force is large is determined depending on the vehicle speed. Therefore, the physical characteristics that the "pitch or roll" of the vehicle body due to the road surface disturbance increases as the vehicle speed increases, and the sensory characteristics that the occupant's sensitivity to the "pitch or roll" becomes sharper as the vehicle speed increases Also, since the damping force control can be adapted, the damping force control can be further optimized.

Further, the fifth feature is applied to a damping force changing mechanism capable of controlling the damping force in at least three steps or more, and if the respective vibrations are in phase, the vibration level of the vehicle body increases in a plurality of orders. The damping force is sequentially increased each time it becomes larger than each set of threshold values, and if the vibrations are in opposite phases, each time the vibration level of the vehicle body becomes larger than each set value of the second set which becomes larger sequentially. Damping force is gradually increased, and the first
The minimum threshold value of the set is set to be larger than the minimum threshold value of the second set. According to this, when the vibration of the vehicle body is “flapping”, the damping force cannot be switched to the larger side unless the vibration level becomes large, and when the vibration of the vehicle body is “pitch and roll” due to road surface disturbance, vibration Even if the level is small, the damping force can be switched to the larger side. Therefore, as in the case of the second feature, the damping force characteristic can be optimally adapted to the physical characteristic and the sensory characteristic.

A sixth feature is that the change width of the first set of threshold values in the fifth feature is smaller than the change width of the second set of threshold values. According to this,
Even if the vehicle body is tilted and the vibration level is increased to some extent and then the damping force is switched to the larger side, that is, even if the vibration energy is increased and the damping force is switched to the larger side, the damping force is The vibrations having a large energy are smoothly and quickly damped because the vibrations having a large energy are sequentially and rapidly transferred.

The seventh characteristic is that, if the respective vibrations are in phase, the smaller vibration level of the respective vibrations detected by the first and second vibration sensors is larger than the threshold value. If the damping force is increased and the vibrations are in opposite phases, the damping force is increased on the condition that the larger vibration level of the vibrations detected by the first and second vibration sensors is larger than a predetermined value. I have tried to do it. According to this, the damping force cannot be switched to the side where the damping force is large unless the vibration level of the vehicle body is large, and the damping force is small at the vibration level of the vehicle body "pitch or roll" due to road surface disturbance. Will be switched to the larger side. Therefore, "pitch or roll"
The control sensitivity of is higher than that in the case of "Aori", and the damping force control can be easily optimized.

An eighth feature is that the level difference between the vibrations is calculated, and the damping force is increased when the calculated level difference is larger than a threshold value. According to this, if the vibration of the vehicle body is “flapping”, each vibration has the same phase, so the calculated level difference becomes a small value,
If the vibration of the vehicle body is "pitch or roll" due to road surface disturbance, the same level difference will be a large value because the vibrations are in opposite phase, so the damping force will not be large for "orientation" unless the vibration level becomes large. It is not possible to switch to the larger side, but to "pitch or roll", the damping force is switched to the larger side with a small vibration level. Therefore, the control sensitivity of the "pitch or roll" is higher than that in the case of "flapping", and the damping force control can be easily optimized.

[0013]

【Example】

a. First Embodiment Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 conceptually shows shock absorbers 10A to 10D as a damping force changing mechanism for a vehicle according to the present invention, and also shows a block diagram of an electric control device 20 for controlling the absorbers 10A to 10D.

The shock absorbers 10A to 10D are respectively arranged between the left and right front wheels and the left and right rear wheels, more specifically, between a lower arm (unsprung member) connected to each wheel and a vehicle body (sprung member). Each shock absorber 10A ~
Reference numeral 10D includes hydraulic cylinders 12a to 12d that are partitioned into upper and lower chambers by pistons 11a to 11d, and the cylinders 12a to 12d are supported by lower arms, respectively. The piston rod 1 is attached to the pistons 11a to 11d.
3a to 13d are respectively connected at the lower ends, and the same rod 1
3a to 13d respectively support the vehicle body at the upper end.
The upper and lower chambers of the hydraulic cylinders 12a to 12d are electromagnetic valves 1
4a to 14d are in communication with each other, and the valves 14a to
The shock absorber 10 is switched by switching the opening of 14d.
The damping force of A to 10D can be switched between two levels (soft and hard). Gas spring units 15a to 15d are connected to the lower chambers of the hydraulic cylinders 12a to 12d, respectively, for absorbing the volume change of the upper and lower chambers caused by the vertical movement of the piston rods 13a to 13d.

The electric control unit 20 is provided with vertical acceleration sensors 21 and 22 mounted at two locations on the vehicle body located in the vicinity of the left and right front wheels (or the left and right rear wheels), and the sensors 21 and 22 are provided at the two locations on the vehicle body. The acceleration associated with the vertical vibration is detected and a detection signal representing the same is output. These vertical acceleration sensors 21 and 22 have a band pass filter 23 having a pass band of 0.5 to 2.0 Hz.
It is connected to the microcomputer 25 via 24. This pass band corresponds to the resonance frequency of the vehicle body, that is, the frequency of "orientation", which is the vertical vibration of the entire vehicle body related to the resonance frequency, and also corresponds to the vibration frequency of the "roll" of the vehicle body due to road surface disturbance. ing. Therefore, the bandpass filters 23 and 24 are the same as the "aori".
And a signal corresponding to the acceleration of each part of the vehicle body due to the "roll", and a signal that is almost equal to the displacement speed of each part of the vehicle body due to the integral action of the circuit itself, that is, the detection indicating the vertical vibration levels LG, RG at the left and right positions of the vehicle body. The signal is output to the microcomputer 25. The vibration levels LG and RG are positive in the upper part and negative in the lower part.

The microcomputer 25 repeatedly executes a program corresponding to the flow chart shown in FIG. 2 at a predetermined short time under the control of a built-in timer circuit to switch the damping forces of the shock absorbers 10A to 10D. . The microcomputer 25 includes a drive circuit 26 corresponding to each of the shock absorbers 10A to 10D.
a-26d are connected to each of the drive circuits 26a-26.
In response to a control signal from the microcomputer 25, d switches and controls the openings of the electromagnetic valves 14a to 14d.

Next, the operation of the embodiment configured as described above will be described. When the ignition switch is turned on, the microcomputer 25 executes an initial setting process (not shown) and then steps 100 to 128 of FIG. 2 every predetermined time.
The program consisting of is repeatedly executed. In the initial setting process, the flag FLG indicating that the shock absorbers 10A to 10D are switched to the hardware state is set.
The initialization is set to 0 "and the control signal indicating the soft state is output to the drive circuits 26a to 26d.
a to 26d store the supplied control signal and set the opening degrees of the electromagnetic valves 14a to 14d based on the stored control signal.
The damping force of D is set to the soft state.

In the program of FIG. 2, step 1
At 02, the vibration levels LG and RG at the left and right positions of the vehicle body are input from the vertical acceleration sensors 21 and 22 through the bandpass filters 23 and 24, respectively. After the input processing, in step 104, absolute values of vibration levels LG and RG | LG
|, | RG | is the vibration magnitude LG at the left and right positions of the vehicle body
1, RG1 and vibration level L at left and right positions
The positive and negative signs of G and RG are set as the vibration directions LGA and RGA (upward when positive, downward when negative) at the lateral position of the vehicle body. Next, at step 106, the magnitudes of vibrations LG1 and RG1 at the left and right positions of the vehicle body are added, and the result of the addition is set as the magnitude of vibration G1 of the vehicle body.

After the processing of steps 102 to 106, the damping force of the shock absorbers 10A to 10D is controlled by the processing of steps 108 to 126. First, the case where the vehicle body does not vibrate or the vehicle body vibrates only slightly will be described. If the magnitude G1 of the vibration of the vehicle body is small and is less than the threshold value GR, "NO" in step 108.
Then, the program proceeds to step 120. In step 120, the initial flag FLG is initially set to "0", so "NO" is determined, the program proceeds to step 128, and the execution of the program is ended in step 128. Therefore, in this case, the shock absorbers 10A to 10D continue to be maintained in the previous state, that is, the soft state. As a result, the damping force with respect to the vertical movement of the vehicle body is set small, and a good ride comfort of the vehicle is secured.

Next, a case where the vehicle body is tilted (the vertical movement of the entire vehicle body related to the resonance frequency of the vehicle body) due to some impact on the vehicle body will be described. In this case, the vibrations at the left and right positions of the vehicle body are in the same phase and the vibration directions LGA and RGA are the same, so in the determination processing of step 110, "YES" is determined and the program proceeds to step 112. Therefore, until the magnitude G1 of the vehicle body vibration becomes equal to or greater than the threshold value GR, it is determined to be "NO" in step 108 and the program is executed in step 1
Proceed to 20. Also, the magnitude G1 of the vibration is the threshold G
Even if it is larger than R, it is judged as "NO" in step 112 and the program is advanced to step 120 until it becomes equal to or larger than the threshold value GH. However, the threshold GH is the threshold G
It is set larger than R in advance. In this case also, since the flag FLG is set to "0", step 120
Is determined to be "NO" and the program execution is ended in step 128. Therefore, the shock absorbers 10A to 10D continue to be maintained in the previous state, that is, the soft state, the damping force with respect to the vertical movement of the vehicle body is set small, and a good ride comfort of the vehicle is secured.

Further, when the tilt of the vehicle body becomes large and the magnitude G1 of vibration of the vehicle body becomes larger than the threshold value GH, it is judged "YES" at step 112 and the program proceeds to step 114. In step 114, a control signal indicating hardware is output to the drive circuits 26a to 26d. The drive circuits 26a to 26d update the previously stored control signal to a control signal representing hardware, switch the opening of the electromagnetic valves 14a to 14d according to the updated control signal, and set the shock absorbers 10A to 10D to hardware. Switch to the state. As a result, shock absorbers 10A-1
A large damping force for the vertical movement of the vehicle body due to 0D is set. After the processing of step 114, the operation of the timer built in the microcomputer 25 is started in step 116, the flag FLG is changed to "1" in step 118, and the execution of the program is ended in step 128.

When the vibration of the vehicle body is damped by the damping force control as described above and the magnitude G1 of the vibration level becomes smaller and becomes less than the threshold value GH, "NO" in step 112.
Then, the program proceeds to step 120. In this case, since the flag FLG is set to "1", it is determined "YES" in step 120 and the program proceeds to step 122. In step 122, it is determined whether or not the timer that has started the operation has counted up to a predetermined value. If the count-up of the timer is not completed, it is determined to be "NO" in step 122 and the execution of the program is ended in step 128. Therefore, the shock absorbers 10A to 10D
Remains in its previous or hard state.

Then, when time elapses after the shock absorbers 10A to 10D are switched from the soft state to the hard state in step 114 and the timer counts up to a predetermined value, "Y" is determined in step 122.
ES ”and the program proceeds to step 124. At step 124, a control signal representing software is output to the drive circuits 26a to 26d. Drive circuit 26a
26d update the previously stored control signal to a control signal representing software, and switch the opening of the electromagnetic valves 14a to 14d according to the updated control signal to switch the shock absorbers 10A to 10D to the soft state. . As a result, the damping force for the vertical movement of the vehicle body by the shock absorbers 10A to 10D is set small. After the processing of step 124, the flag FLG is set to "1" in step 126.
The value is changed to 0 "and the program execution is ended in step 128.

Thus, when the vehicle body is tilted and the magnitude G1 of the vibration of the vehicle body caused by the tilt becomes larger than the threshold value GH, the shock absorbers 10A to 10D are switched from the soft state to the hard state, and this state is set. Is maintained for a predetermined time even if the magnitude G1 of the vibration of the vehicle body becomes small. Therefore, when the body tilt increases,
Since the damping force with respect to the vertical movement of the vehicle body due to the tilt is always maintained on the large side for a predetermined time, the tilt of the vehicle body is suppressed.

Next, the case where the vehicle body rolls due to a road surface disturbance will be described. In this case, the vibrations at the left and right positions of the vehicle body have opposite phases, and the vibration directions LGA, RG
Since A is different, it is determined as "NO" in the determination processing of step 110 and the program proceeds to step 114. Therefore, the magnitude G1 of the vehicle body vibration is equal to the threshold G
Until R or more, the program proceeds to step 120 by making a “NO” determination in step 108, so that the shock absorbers 10A to 10D continue to be in the previous state, that is, the soft state, as in the case described above. The damping force with respect to the vertical movement of the vehicle body is set small so that a good ride comfort of the vehicle is secured.

On the other hand, when the roll of the vehicle body due to the road surface disturbance becomes large and the magnitude G1 of the vehicle body vibration becomes larger than the threshold value GR, the shock absorbers 10A to 10D are switched to the hard state by the processing of step 114 described above. Set a large damping force for vertical movement of the vehicle body. After the processing of the step 114, the above-mentioned step 116,
The timer is started by the processing of 118 and the flag FLG is changed to "1". By the processes of steps 120 to 126 described above, the shock absorbers 10A to 10D are maintained in the hard state for a predetermined time, and the flag FLG is returned to "0". Therefore, when the roll of the vehicle body increases due to the road surface disturbance, the damping force for the vertical movement of the vehicle body caused by the roll is always maintained on the large side for a predetermined time, so that the roll of the vehicle body is suppressed.

As can be understood from the above description of the operation, according to the first embodiment, if the vibration of the vehicle body is related to "flapping", the vibration magnitude G1 does not exceed the comparatively large threshold value GH. As far as possible, the damping force cannot be switched to the larger side. On the other hand, if the vibration of the vehicle body is related to the roll due to the road surface disturbance, the damping force is switched to the larger side when the vibration magnitude G1 becomes equal to or larger than the comparatively small threshold value GR. That is, the control sensitivity of the damping force to the roll of the vehicle body is set higher than the control sensitivity of the damping force to the tilt of the vehicle body. These things are compatible with the general physical characteristics that the vibration level of the roll of the car body is smaller than the vibration level of the tilt, and also the sensory characteristics that the occupant feels the roll more sensitive than the tilt. Therefore, the optimal damping force control is performed both physically and sensibly.

B. Second Embodiment Next, a second embodiment of the present invention will be described. This second
In the embodiment, as shown in FIG. 1, a vehicle speed sensor 27 is further connected to the microcomputer 25 of the first embodiment. The vehicle speed sensor 27 detects the vehicle speed V and outputs a detection signal indicating the vehicle speed V. Further, in the second embodiment, the microcomputer 25 executes the program in which only the steps 100 to 112 of the program of the first embodiment are replaced with a part of the program shown in FIG. 3 at predetermined time intervals. In addition, the microcomputer 25 is provided with a table that stores data representing threshold values GR and GH that change with the characteristics shown in FIG. 4 according to the vehicle speed V. The remaining part is the same as in the first embodiment.

The operation of the second embodiment will be described below. After the initialization processing similar to that of the first embodiment, the microcomputer 25 proceeds to step 102a of FIG. 3 to determine the vibration levels LG and RG at the left and right positions of the vehicle body. In addition to the vehicle speed sensor 27
Enter the vehicle speed V from. After the processing of step 102a, the magnitude LG of the vibration at the left and right positions of the vehicle body is processed by the processing of steps 104 and 106 similar to the first embodiment.
1, RG1, vibration directions ALG, ARG, and vibration magnitude G1 are calculated, and in step 150, the built-in table is referred to and thresholds GR, GH (FIG. 4) corresponding to the vehicle speed V are calculated.
Refer to).

Next, by the determination processing of step 152 similar to step 110 of the first embodiment, it is determined whether the vibration of the vehicle body is a tilt related to the resonance frequency or a roll due to a road surface disturbance. . If the vibrations at the vehicle body left and right positions are in phase and the vibrations of the vehicle body are related to the tilt, it is determined to be “YES” in step 152 and the program proceeds to step 154. In step 154, it is determined whether the magnitude G1 of vibration of the vehicle body is equal to or greater than the threshold value GH. If the magnitude G1 of vibration is equal to or larger than the threshold value GH, it is determined to be “YES” in step 154 and the program proceeds to step 114 in FIG. 2. If the magnitude G1 is smaller than the threshold value GH, step 154 is performed. Is determined as "NO" and the program proceeds to step 120. Therefore, when the vehicle body is tilted and the magnitude G1 of the vibration of the vehicle body due to the tilting exceeds the threshold value GH, the damping force for the vertical movement of the vehicle body due to the tilting is always maintained on the large side for a predetermined time. Therefore, the tilt of the vehicle body is suppressed. Further, when the magnitude G1 of the vibration of the vehicle body is kept below the threshold value GH, the damping force with respect to the vertical movement of the vehicle body is kept small, so that the riding comfort of the vehicle is kept good.

On the other hand, if the vibrations at the left and right positions of the vehicle body are in opposite phases and the vibration of the vehicle body is related to the roll caused by the road surface disturbance, it is determined to be "NO" at step 152 and the program proceeds to step 156. In step 156, it is determined whether the magnitude G1 of vibration of the vehicle body is equal to or larger than the threshold value GR. If the magnitude of vibration G1 is greater than or equal to the threshold value GR, it is determined as "YES" in step 156 and the program proceeds to step 114 in FIG. 2, and if the magnitude G1 is less than the threshold value GR, step 156. Is determined as "NO" and the program proceeds to step 120. Therefore, a roll due to road surface disturbance is generated on the vehicle body, and the magnitude G1 of vibration of the vehicle body due to the roll is the threshold value G.
When it becomes R or more, the damping force with respect to the vertical movement of the vehicle body caused by the roll is always maintained on the larger side for a predetermined time, so that the roll of the vehicle body is suppressed. Further, when the magnitude G1 of the vibration of the vehicle body is kept below the threshold value GR, the damping force for the vertical movement of the vehicle body is kept small, so that the riding comfort of the vehicle is kept good.

In this case, the threshold value GH relating to the tilt of the vehicle body becomes smaller as the vehicle speed V becomes higher, and the threshold value GR relating to the roll of the vehicle body due to the external force on the road surface.
Increases as the vehicle speed V increases (see FIG. 4). Therefore, according to the second embodiment described above, as the vehicle speed V becomes higher, the damping force for the tilt of the vehicle body is easily switched to the larger side, and the damping force for the roll of the vehicle body due to the road surface disturbance is switched to the larger side. It will be difficult. This means that the damping force control can be adapted to the physical characteristics that the vehicle body tilt becomes lower due to the down force as the vehicle speed becomes higher, and the vehicle body roll due to the road surface disturbance becomes larger. Force control is realized. This third
Although the control of the embodiment seems to conflict with the control of the second embodiment, these controls are appropriately selected according to the type of vehicle.

C. Third Embodiment Next, a third embodiment of the present invention will be described. This third
In the embodiment, the microcomputer 25 stores a table storing the data representing the threshold values GR and GH that change with the characteristics shown in FIG. 5 according to the vehicle speed V, instead of the table of the second embodiment. And step 1 in FIG.
The only difference is that the threshold values GR and GH are determined with reference to the same table at 50.

Therefore, the roll of the vehicle body due to the tilt of the vehicle body and the road surface disturbance is the same as in the case of the second embodiment.
It is suppressed when the magnitude G1 of the vehicle body vibration exceeds the threshold values GH and GR. In this case, the threshold value GH related to the tilt of the vehicle body increases as the vehicle speed V increases, and the threshold value GR related to the roll of the vehicle body due to the road surface external force decreases as the vehicle speed V increases ( (See FIG. 5). Therefore, the third
According to the embodiment, as the vehicle speed V increases, the damping force against the tilt of the vehicle body becomes difficult to switch to the larger side, and the damping force against the roll of the vehicle body due to the road surface disturbance easily switches to the larger side. This is
The damping force control can be adapted to the sensory characteristics that the sensitivity of the occupant to the tilt of the vehicle body becomes weaker as the vehicle speed increases, and the sensitivity to the occupant's roll becomes sharper, and better damping force control is realized. To be done.

D. Fourth Embodiment Next, a fourth embodiment of the present invention will be described. This fourth
In the embodiment, the shock absorbers 10A to 10D
The opening degree of the electromagnetic valves 14a to 14d of 4 includes the initial state 4
It is switched to the stage, and the absorber 1 is correspondingly changed.
The damping force of 0A to 10D can be switched in four steps. This initial state corresponds to the soft state of the first embodiment, and the first to third states correspond to the increasing direction of the damping force in this order. Further, in the fourth embodiment, the microcomputer 25 executes the programs shown in FIGS. 6 to 8 instead of the program of the first embodiment every predetermined short time, and the shock absorber 10A.
Data representing thresholds GR and GH (FIG. 9 or FIG. 10) for switching to the first to third states of ˜10D are stored. The remaining part is the same as in the first embodiment.

The operation of the fourth embodiment will be described below. The microcomputer 25 executes the processing of steps 200 to 214 in FIG. 6 after the initialization processing similar to that of the first embodiment. In this initial setting process, the shock absorbers 10A to 10D are set to the initial state, and are being switched to the first to third states of the absorbers 10A to 10D related to the "orientation" and "roll" of the vehicle body. Flags that indicate that HFLG1 to HFLG3, RFLG1 to RFLG3
Is set to "0". Step 202 after this initialization
To 206, step 102 of the first embodiment described above.
~ 106 (Fig. 2), input each vibration level LG, RG of the left and right position of the vehicle body, each input vibration level L
Based on G and RG, the magnitudes of vibrations LG1 and RG1, the directions of vibrations ALG and ARG, and the magnitude of vibration G1 at the vehicle body left and right positions are calculated.

Next, at step 208, it is judged whether or not the vibrations at the left and right positions of the vehicle body are in phase based on the vibration directions ALG and ARG at the left and right position of the vehicle body. If the vibrations of the vehicle body left and right positions are in phase, it is determined to be "YES" in step 208, the tilt control routine is executed in step 210, and the program execution is ended in step 214. If the vibrations of the vehicle body left and right positions are in opposite phases, it is determined to be "NO" in step 208, the roll control routine is executed in step 212, and the execution of the program is ended in step 214.

As shown in detail in FIG. 7, the tilt control routine starts its execution at step 220 and executes the judgment processing at steps 222-232. The magnitude G1 of vibration of the vehicle body is the threshold value GH1, GH2, GH
If it is smaller than any of the three, each flag HFLG1, HFLG2, HF
Since LG3 is initially kept at "0", it is determined to be "NO" at all steps 222 to 232, and step 2 is performed.
At 58, the execution of this tilt control routine ends. Therefore, in this case, the shock absorbers 10A to 10A
Since D is kept in the initial state and the damping force for the vertical movement of the vehicle body is kept low, the riding comfort of the vehicle is kept good.

On the other hand, if the magnitude G1 of the vibration of the vehicle body exceeds the threshold value GH1 (see FIG. 9 or FIG. 10) in a state where the left and right vibrations of the vehicle body are in the same phase, the result of step 230 is "YES". The determination is made and the program proceeds to step 234. In step 234, as in the first embodiment, the electromagnetic valve 14 is driven through the drive circuits 26a to 26d.
The shock absorbers 10A to 1d are controlled by controlling a to 14d and switching the opening of the valves 14a to 14d.
0D is switched from the initial state to the first state. After the processing of step 234, the timer built in the microcomputer 25 is started in step 236, and the flag HFLG1 is changed to "1" in step 238. And
The shock absorbers 10A to 10D are kept in the first state for a predetermined time by the processing of steps 232 and 252 similar to the first embodiment, and after the predetermined time has elapsed, step 25
The absorbers 10A to 10D by the processing of 2,254
To the initial state. At this point, the flag HFLG1 is returned to "0" by the processing of step 256. As a result, the shock absorbers 10A to 10D are maintained in the first state for a predetermined time, and the damping force increases, so that the tilting of the vehicle body is quickly suppressed.

Further, the tilt of the vehicle body is larger than that in the above case, and the magnitude G1 of the vibration of the vehicle body is equal to the threshold value GH2.
(See FIG. 9 or FIG. 10) When the above is completed, step 226
Then, the program is judged to be "YES" and the program is executed at step 240
~ Proceed to 244. In steps 240 to 244, similarly to steps 234 to 238, the shock absorbers 10A to 10D are switched to the second state, the timer is started, and the flag HFLG2 is changed to "1". Then, in this case, steps 228 and 23
Shock absorber 10A through processing of 2,252
10D is kept in the second state for a predetermined time, and after the lapse of the predetermined time, the absorbers 10A to 10D are returned to the initial state by the processing of steps 252 to 256, and the flag HF is set.
Reset LG2 to "0". As a result, since the shock absorbers 10A to 10D are maintained in the second state for a predetermined time and the damping force becomes larger than the above, the tilt can be promptly suppressed even if the tilt of the vehicle body becomes slightly larger than the above case. .

Further, when the tilt of the vehicle body is further increased and the magnitude G1 of vibration of the vehicle body becomes equal to or larger than the threshold value GH3 (see FIG. 9 or 10), "YE" is determined in step 222.
S ”is determined and the program proceeds to steps 246 to 250. In steps 246 to 250, similarly to the steps 234 to 238 and 240 to 244, the shock absorbers 10A to 10D are switched to the third state, the timer is started, and the flag HFLG3 is set to "1".
Change to And in this case, step 224,
The shock absorbers 10A to 10D are kept in the third state for a predetermined time by the processing of 228, 232, 252, and after the predetermined time has elapsed, the shock absorbers 10A to 10D are returned to the initial state by the processing of steps 252 to 256, and the flag HFLG3 is set. Is reset to "0". As a result, the shock absorbers 10A to 10D are maintained in the third state for a predetermined period of time, and the damping force is further increased. Therefore, even if the vehicle body tilt is further increased, the tilt is quickly suppressed.

Next, the roll control routine will be described. The roll control routine comprises steps 260 to 298 as shown in detail in FIG.
8 is steps 220 to 2 of the tilt control routine described above.
58 respectively. However, step 26
2, 266, 270, thresholds GR3, GR2, GR1 (FIG. 9 or FIG.
0), and determined in steps 264, 268, 272 and in steps 278, 284, 290, 296 "
Flags RFLG3, RFLG2, RFLG1 set to 1 "or" 0 "
Is different from the case of the tilt control routine. Therefore, also in the processing of this roll control routine, as the magnitude G1 of the vibration of the vehicle body related to the tilt increases, the damping forces of the shock absorbers 10A to 10D are sequentially switched to the larger side. As the magnitude G1 of the vibration of the vehicle body increases, the damping force of the shock absorbers 10A to 10D is sequentially switched to the larger side. As a result, the ride comfort of the vehicle is maintained good if no roll occurs in the vehicle body, and if the roll occurs, the vehicle body roll is quickly suppressed by the damping force control according to the size of the roll. .

In the fourth embodiment constructed as described above, as shown in FIG. 9 or FIG. 10, the minimum threshold value G among the threshold values GH1 to GH3 related to the tilt of the vehicle body.
H1 is a threshold value GR1 to GR3 related to the roll of the vehicle body
Since the roll-related vibration is set to a value larger than the minimum threshold value GR1 of the above, the vibration is controlled with high sensitivity in the initial stage as compared with the vibration of the vehicle body related to the tilt.
That is, in the case of vibration of the vehicle body, the damping force cannot be switched to the larger side unless the vibration level increases.
On the other hand, when the vibration of the vehicle body is a roll of the vehicle body caused by the road surface disturbance, the damping force is switched to the larger side even if the vibration level is small. Therefore, also in this case, the damping force characteristics of the shock absorbers 10A to 10D can be optimally adapted to the physical characteristics and the sensory characteristics.

Further, in the fourth embodiment, as shown in FIG. 9 or 10, the change width of the threshold values GH1 to GH3 related to the tilt of the vehicle body is set to the threshold values GR1 to GR1 related to the roll of the vehicle body. It is smaller than the change width of GR3. According to this, even if the vehicle body is tilted and the vibration level is increased to a certain extent and then switched to the larger damping force side, that is, even if the vibration energy is increased to the greater damping force side, Since the damping force gradually and rapidly shifts to the larger side, the vibration of large energy is smoothly and quickly damped.

In the fourth embodiment, the shock absorbers 10A to 10D are switched to four stages including the initial state, but the number of stages may be three stages or five or more stages. In this case, the electromagnetic valve 14a
It is only necessary to prepare shock absorbers 10A to 10D capable of switching ˜14d to the number of stages, and delete or add the processing corresponding to each stage in the programs of FIGS. Further, in the fourth embodiment, the holding time when switching the shock absorbers 10A to 10D to the first to third states is common, but the holding time is different for each state, for example, it becomes a higher state. Accordingly, the holding time may be extended. In this case,
In each of steps 252 and 292, the time for counting up the timer may be made different according to each switching state.

E. Fifth Embodiment Next, a fifth embodiment of the present invention will be described. This fifth
The embodiment is different from the first embodiment in that the microcomputer 25 executes the program shown in FIG. 11 instead of the program shown in FIG. 2, and the rest is the same as the first embodiment.

The operation of the fifth embodiment will be described below. After the initial setting processing similar to that of the first embodiment, the microcomputer 25 performs the vibrations at the left and right positions of the vehicle body by the processing of steps 302 and 304 in FIG. The levels LG and RG are input, and the magnitudes of vibrations LG1 and RG1 and the directions of vibrations ALG and ARG at the vehicle body left and right positions are calculated based on the respective vibration levels LG and RG. Next, by the processing of steps 306 to 310, the larger one of the vibration magnitudes LG1 and RG1 at the left and right positions of the vehicle body is set as the maximum vibration value Gmax, and the smaller one is set as the minimum vibration value Gmin. Steps 306-3
After the processing of step 10, in step 312, similarly to the above-described first embodiment, it is determined in step 312 whether the vibration directions LGA and RGA in the left and right positions of the vehicle body are the same. It is determined whether it is caused by a tilt or a roll due to a road surface disturbance.

If both the vibration directions LGA and RGA are the same and the vibration of the vehicle body is related to the tilt, it is judged "YES" in step 312 and the program is advanced to step 314. In step 314, the minimum vibration value Gmin is compared with a predetermined threshold value G to determine whether the minimum vibration value Gmin is equal to or greater than the threshold value G.
If the minimum vibration value Gmin is greater than or equal to the threshold value G, it is determined to be "YES" in step 314 and the same processing of steps 318 to 322 as steps 114 to 118 of the above-described first embodiment is executed to make a shock. The damping force of the absorbers 10A to 10D is switched to the larger side. On the other hand, the minimum vibration value Gmi
If n is less than the threshold G, then in step 314 “N
"O" and steps 120 to 12 of the first embodiment.
By executing the processing of steps 324 to 330 similar to step 6,
The damping force of the shock absorbers 10A to 10D is maintained on the larger side for a predetermined time, and then the damping force is returned to the smaller side.

If the vibration directions LGA and RGA are different and the vibration of the vehicle body is related to the roll due to the road surface disturbance, it is determined to be "NO" at step 312 and the program proceeds to step 316. In step 316, the maximum vibration value Gmax is compared with the same threshold value G as described above to determine whether or not the maximum vibration value Gmax is greater than or equal to the threshold value G. If the maximum vibration value Gmax is greater than or equal to the threshold value G, it is determined to be "YES" in step 316, the program proceeds to steps 318 to 322, and the damping force of the shock absorbers 10A to 10D is switched to the larger side. On the other hand, if the maximum vibration value Gmax is less than the threshold value G, it is determined to be "NO" in step 316, the program proceeds to steps 324 to 330, and the damping force of the shock absorbers 10A to 10D is increased for a predetermined time. Side, and then return the damping force to the smaller side.

As can be understood from the above description of the operation, according to the fifth embodiment, when the minimum vibration value Gmin exceeds the threshold value G when the vehicle body is tilted, the damping force for the vertical movement of the vehicle body is increased. When the maximum vibration value Gmax becomes equal to or greater than the threshold value G when the vehicle body is rolled due to a road surface disturbance, the vehicle body is switched to the larger damping force for the vertical movement of the vehicle body. Therefore,
The roll of the vehicle body due to the road surface disturbance is more likely to be switched to the side having a larger damping force than the tilt of the vehicle body, that is, the control sensitivity of the damping force becomes higher. Therefore, also in the fifth embodiment, it is possible to control the optimum damping force that suits the occupant's sensation by the tilt and roll of the vehicle body. Further, since only one type of threshold value G to be compared with the maximum vibration value Gmax and the minimum vibration value Gmin needs to be provided, the structure is simplified. In particular, the threshold G is set to the second and third
When changing according to the vehicle speed V as in the embodiment, it is not necessary to provide a plurality of tables.

F. Sixth Embodiment Next, a sixth embodiment of the present invention will be described. This 6th
In the embodiment, as shown in FIG. 1, a vehicle speed sensor 27 is further connected to the microcomputer 25 of the fifth embodiment. The vehicle speed sensor 27 detects the vehicle speed V and outputs a detection signal indicating the vehicle speed V. Further, in the sixth embodiment, the microcomputer 25 executes the program in which only the steps 300 to 312 of the program of the fifth embodiment are replaced with a part of the program shown in FIG. 11 every predetermined short time. To do. The remaining part is the same as in the fifth embodiment.

The operation of the sixth embodiment will be described below. After the initialization processing similar to that of the fifth embodiment, the microcomputer 25 executes steps 302a and 304 of FIG.
By the processing of 310 to 310, the respective vibration levels LG, RG at the left and right positions of the vehicle body and the vehicle speed V are inputted, and the respective vibration levels LG, RG,
Based on RG, the magnitude of vibration at the left and right positions of the vehicle body LG
1, RG1 and vibration directions ALG, ARG are calculated, and maximum vibration value Gmax and minimum vibration value Gmin are set.
Next, at step 340, it is determined whether the vehicle speed V is equal to or lower than a predetermined value V ₁ . This predetermined value V ₁ represents the vehicle speed at which the threshold value for tilt and the threshold value for roll intersect as shown in FIG.

If the vehicle speed V is less than or equal to the predetermined value V ₁ , it is determined "YES" in step 340 and the program proceeds to step 342. In step 342, if the vibration of the vehicle body is related to the tilt, the program is advanced to step 314 by the same determination processing as in step 312 of the fifth embodiment, and if the vibration of the vehicle body is related to the tilt. If so, the program proceeds to step 316. Therefore, when the vehicle speed V is low to medium, as in the case of the fifth embodiment, when the minimum vibration value Gmin becomes equal to or greater than the threshold value G when the vehicle body tilts, the vehicle body moves up and down. When the damping force is switched to the larger side and a roll occurs due to road surface disturbance on the vehicle body, the maximum vibration value Gma
When x becomes equal to or greater than the threshold value G, the damping force for the vertical movement of the vehicle body is switched to the larger side. That is, the sensitivity of the damping force control for the roll of the vehicle body is set higher than the sensitivity of the damping force control for the tilt of the vehicle body.

On the other hand, when the vehicle speed V becomes higher than the predetermined value V ₁ , it is judged "NO" in step 340 and the program proceeds to step 344. In step 344, if both vibration directions LGA and RGA are the same and the vibration of the vehicle body is related to the tilt, it is determined to be “YES” and the program proceeds to step 316, where both vibration directions LGA and RGA
If the RGA is different and the vibration of the vehicle body is related to the roll caused by the road surface disturbance, it is determined to be "NO" and the program proceeds to step 314. Therefore, when the maximum vibration value Gmax becomes equal to or larger than the threshold value G when the vehicle body is tilted, it is switched to the side where the damping force for the vertical movement of the vehicle body is large and the vehicle body is rolled due to the road surface disturbance. When the minimum vibration value Gmin becomes equal to or greater than the threshold value G, the switching is switched to the side where the damping force for the vertical movement of the vehicle body is large.
That is, the sensitivity of the damping force control for the tilt of the vehicle body is set higher than the sensitivity of the damping force control for the roll of the vehicle body.

As described in the second embodiment, this has the physical characteristic that as the vehicle speed increases, the downforce of the vehicle body decreases due to downforce, and the vehicle body roll due to road surface disturbance increases. Fits. Therefore, according to the sixth embodiment, in addition to the effect of the fifth embodiment, better damping force control is realized.

In the sixth embodiment, the threshold value G compared with the maximum vibration value Gmax and the minimum vibration value Gmin is made different depending on whether the vehicle speed V is equal to or lower than a predetermined value V ₁ or higher. Good. In this case, the vehicle speed V is the predetermined value V
If it is ₁ or less, the processes of steps 314 and 316 are executed based on the determination of step 342, as in the embodiment. Then, a pair of determination processes having different thresholds is performed by the same process as steps 314 and 316.
14 and 316 may be newly provided in parallel, and the newly provided determination processing may be performed based on the determination in step 344.

G. Seventh Embodiment Next, a seventh embodiment of the present invention will be described. This 7th
In the embodiment, the microcomputer 25 executes steps 300 to 316 (FIG. 1) of the program of the fifth embodiment.
The program in which only the portion 1) is replaced with a part of the program shown in FIG. 13 is executed every predetermined short time. The remaining part is the same as in the fifth embodiment.

The operation of the seventh embodiment will be described below. After the initialization processing similar to that of the fifth embodiment, the microcomputer 25 determines the vibration levels LG and RG at the left and right positions of the vehicle body by the processing of step 302. input. After this input, in step 350, the absolute value | LG-RG | of the difference LG-RG between the vibration levels LG and RG is calculated, and the same absolute value | LG-RG | is set as the level difference G1. Next, in step 352, the level difference G1 is compared with a predetermined threshold value G ₀ to determine whether the level difference G 1 is equal to or greater than the threshold value G ₀ .

If the level difference G1 is greater than or equal to the threshold value G ₀ , it is judged "YES" in step 352 and the program is advanced to steps 318 to 322 to increase the damping force of the shock absorbers 10A to 10D to the larger side. Switch.
On the other hand, if the level difference G1 is less than the threshold value G ₀ , it is determined to be “NO” in step 352, the program proceeds to steps 324 to 330, and the shock absorber 10
Maintain the damping force of A to 10D on the large side for a predetermined time,
After that, the damping force is returned to the smaller side.

In this case, each vibration level L at the left and right positions of the vehicle body is caused even if the vehicle body vibration is caused by the tilt.
There is some difference between G and RG, but the difference is small. On the other hand, if the vibration of the vehicle body is caused by the rolling of the vehicle body due to the road surface disturbance, the difference between the vibration levels LG and RG becomes considerably large. Therefore, the control sensitivity of the damping force related to the roll is higher than in the case of the tilt, and the damping force control can be easily optimized.

H. Eighth Embodiment Next, an eighth embodiment of the present invention will be described. This 8th
In the embodiment, as shown in FIG. 1, a vehicle speed sensor 27 is further connected to the microcomputer 25 of the fifth embodiment. The vehicle speed sensor 27 detects the vehicle speed V and outputs a detection signal indicating the vehicle speed V. In addition, in the eighth embodiment, the microcomputer 25 executes steps 300 to 316 (FIG. 11) of the program of the fifth embodiment.
The program in which only the part of FIG. 14 is replaced with a part of the program shown in FIG. 14 is executed every predetermined short time. The remaining part is the same as in the fifth embodiment.

The operation of the eighth embodiment will be described below. After the initialization processing similar to that of the fifth and seventh embodiments, the microcomputer 25 executes step 3 of FIG.
By the processing of 02 and 350, the respective vibration levels LG and RG at the left and right positions of the vehicle body are inputted and the respective vibration levels L
Level difference G1 (= | LG-RG |) based on G and RG
Is calculated. Next, at step 360, each vibration level L
The absolute value | LG + RG | of the sum LG + RG of G and RG is calculated, and the same absolute value | LG + RG | is set as the level sum G2. After calculating the level difference G1 and the level sum G2, it is determined in step 362 whether the vehicle speed V is equal to or lower than a predetermined value V ₁ . This predetermined value V ₁ represents the vehicle speed at which the threshold value for tilt and the threshold value for roll intersect as shown in FIG.

If the vehicle speed V is less than or equal to the predetermined value V ₁ , it is determined to be "YES" in step 362 and the program proceeds to step 364. In step 364, if the level difference G1 is greater than or equal to a predetermined threshold value G ₀₁ by the same determination processing as in step 352 of the seventh embodiment, “Y” is determined.
"ES" is determined and the program is executed in steps 318 to 322.
If the level difference G1 is less than the predetermined threshold value G ₀₁ , it is determined to be "NO" and the program is executed in step 324.
Proceed to ~ 330. Therefore, if the vehicle speed V is low to medium, the shock absorber 10A to the shock absorbers 10A to 10A when the level difference G1 becomes equal to or larger than the threshold value G ₀₁ as in the case of the seventh embodiment.
The damping force of 10D is switched to the larger side.

On the other hand, when the vehicle speed V becomes higher than the predetermined value V ₁ , it is determined to be "NO" at step 362 and the program proceeds to step 366. In step 366, it is determined whether the level sum G2 is equal to or larger than a predetermined threshold value G ₀₂ . In this case, if the level sum G2 is greater than or equal to the threshold value G ₀₂ , it is determined to be "YES" and the program proceeds to steps 318 to 322. If the level sum G2 is less than the threshold value G ₀₂ , it is determined to be "NO". Then, the program proceeds to steps 324 to 330. Therefore, the vehicle speed V
Is high, when the level sum G2 becomes equal to or greater than the threshold value G ₀₂ , the shock absorbers 10A to 10D are switched to the side where the damping force is large.

As described above, the level difference G1 between the vibration levels LG and RG is small if the vibration of the vehicle body is caused by the tilt, and if the vibration of the vehicle body is caused by the roll of the vehicle body due to the road surface disturbance. large. On the other hand, on the contrary, the level sum G2 is large if the vibration of the vehicle body is caused by the vibration of the vehicle body, and is small if the vibration of the vehicle body is caused by the roll of the vehicle body due to the road surface disturbance. Therefore,
The control sensitivity of the damping force to the body tilt is set to be higher than the control sensitivity of the body roll to the roll of the vehicle during low- and medium-speed running, and the control sensitivity of the damping force to the body tilt during the high-speed running of the vehicle. Is set lower than the control sensitivity of the damping force to the roll of the vehicle body. As described in the second embodiment, this also applies to the physical characteristics that the vehicle body tilt becomes lower due to the down force as the vehicle speed becomes higher, and the vehicle body roll due to the road surface disturbance becomes larger. Therefore, according to the eighth embodiment, in addition to the effects of the seventh embodiment, a better damping force control is realized.

I. Modified Example of Same Reversed Phase Determination Next, a modified example of the means for determining the same reversed phase of the vibration at the left and right positions of the vehicle body used in the first to sixth embodiments will be described. This modification is composed of the same reverse phase determination program of FIG. 15 which is executed by the microcomputer 25 of each of the above embodiments.

The microcomputer 25 repeatedly executes the processing of steps 400 to 416 of FIG. 15 at every predetermined short time. At step 402, the vertical acceleration sensor 2 of FIG.
1 and 22 are input via band-pass filters 23 and 24. Next, by the processing of steps 404 and 406,
Vibration level LG, R at the time of the previous program execution
The old vibration levels LGo and RGo representing G are updated with the new vibration levels LGn and RGn representing the vibration levels LG and RG at the time of execution of the program this time, respectively, and the new vibration levels LGn and RGn are inputted into the vibration level L entered this time.
Set to G and RG.

After the processes of steps 402 to 406, in step 408, the vibration level waveform at the left position of the vehicle body is determined depending on whether the product LGn · LGo of the old and new vibration levels LGn, LGo at the left position of the vehicle body is negative. L in FIG.
(See G) has a zero crossing. If the vibration level waveform crosses zero, in step 408, "YE
"S", and in step 410, the difference Rg between the old and new vibration levels LGn, LGo at the left position of the vehicle body and the difference R between the old and new vibration levels RGn, RGo at the right position of the vehicle body.
It is determined whether or not the product (LGn-LGo) .multidot. (RGn-RGo) with Gn-RGo is positive. The determination processing in step 410 determines whether the vibrations at the left and right positions of the vehicle body are in phase or in opposite phase, and the differences LGn-LGo, R are calculated.
Gn-RGo represents the slope of each vibration waveform,
In the case of in-phase, the slopes of both vibration waveforms match (L in FIG. 16).
G and RG-1) and opposite phases have different inclinations of the vibration waveforms (corresponding to LG and RG-2 in FIG. 16).

That is, if the vibrations at the left and right positions of the vehicle body are in phase and the product (LGn-LGo) .multidot. (RGn-RGo) is positive, it is determined to be "YES" in step 410, and step 412 is executed. And sets the in-phase flag SFLG to "1". On the other hand, if the vibrations at the left and right positions of the vehicle body are in opposite phase and the product (LGn-LGo) * (RGn-RGo) is negative, it is determined to be "NO" in step 410 and the same is determined in step 414. The reverse phase flag SFLG is set to "0". The flag SFLG set in this way is maintained at the set value because it is continuously determined as "NO" in step 408 until the vibration waveform at the left position of the vehicle body crosses zero next time. Therefore, also in this modification, the in-phase or anti-phase of each vibration at the left and right positions of the vehicle body is determined. When this determination result is applied to the first to sixth embodiments, step 110 in FIG. 2, step 152 in FIG. 3, step 208 in FIG. 6, step 312 in FIG. 11, step 312 in FIG.
The determination processing of steps 342 and 344 may be performed according to the value of the in-phase flag SFLG according to this modification.

In this modification, when the vibration waveform at the left position of the vehicle body is zero-crossed, the in-phase or opposite phase of the vibration at the left-right position of the vehicle body is determined, but at the time of zero-crossing the vibration waveform at the right position of the vehicle body. You may make it determine the same phase or opposite phase of the vibration in the left-right position of a vehicle body. In this case, in step 408, instead of using the product LGn · LGo of the old and new vibration levels LGn, LGo at the left position, the new and old vibration levels RGn, Ln at the right position are used.
The product RGn · RGo of RGo may be used.

J. Other Modifications In each of the above-described embodiments, the vertical acceleration sensor 2 is used as the vibration sensor for detecting the vibration at the left and right positions of the vehicle body.
Although the vertical acceleration sensors 21 and 22 are used, instead of these vertical acceleration sensors 21 and 22, a vehicle height sensor that is mounted on the vehicle body to detect the height from the road surface, and is provided in the suspension device and is mounted on the vehicle body (the sprung member). ) And a wheel side member (unsprung member), a stroke sensor for detecting relative displacement, a load sensor provided in the shock absorber for detecting a load applied to the absorber, and an air suspension as a damping force changing mechanism. A damping force sensor that detects the air pressure in the air suspension and the hydraulic pressure in the shock absorber when used can also be used as the vibration sensor.

Further, in the above embodiment, the damping force control is performed by distinguishing the vehicle body tilt and the vehicle body roll due to the road surface disturbance, but the vehicle body roll due to the road surface disturbance and the vehicle body pitch due to the road surface disturbance are substantially the same. Therefore, the above-described respective embodiments can be applied to those in which the damping force is controlled by distinguishing the vehicle body tilt and the vehicle body pitch. In this case, the vertical acceleration sensors 21 and 22 of the above-described embodiment or the vibration sensors according to each of the above modifications may be provided at the front and rear positions of the vehicle body, for example, the front and rear wheel positions. According to this, if the respective vibrations detected by the respective vibration sensors are in phase, the vibrations of the vehicle body are treated as being related to the tilt, and if the respective detected vibrations are in the opposite phase, the vehicle body vibrations are Treated as related to the pitch.

Further, three or more vibration sensors may be provided on the vehicle body at different positions on the plane, and the damping force may be controlled by the outputs of these sensors. In this case, assuming a plane corresponding to the position of each sensor, if the plane is displaced in parallel in the vertical direction based on the vibration detected by each sensor, that is, if the detected vibration is in phase, It may be determined that the tilt is occurring. Further, when the plane is twisted and displaced, that is, when the detected vibrations are not in phase, it may be determined that a roll or pitch has occurred in the vehicle body.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a damping force control device common to each embodiment of the present invention.

FIG. 2 is a flowchart showing a program according to the first embodiment of the present invention.

FIG. 3 is a flowchart showing a part of a program according to a second embodiment of the present invention.

FIG. 4 is a characteristic graph of change in threshold value with respect to vehicle speed according to a second embodiment of the present invention.

FIG. 5 is a graph showing a change characteristic of a threshold value with respect to a vehicle speed according to a third embodiment of the present invention.

FIG. 6 is a flowchart showing a main program according to a fourth embodiment of the present invention.

FIG. 7 is a flowchart showing details of the tilt control routine of FIG.

FIG. 8 is a flowchart showing details of the roll control routine of FIG.

FIG. 9 is a graph showing an example of the relationship between the switching stage number and the threshold value of the shock absorber according to the fourth embodiment of the present invention.

FIG. 10 is a graph showing another example of the relationship between the switching stage number and the threshold value of the shock absorber according to the fourth embodiment.

FIG. 11 is a flowchart showing a program according to a fifth embodiment of the present invention.

FIG. 12 is a flowchart showing a part of a program according to a sixth embodiment of the present invention.

FIG. 13 is a flowchart showing a part of a program according to the seventh embodiment of the present invention.

FIG. 14 is a flowchart showing a part of a program according to an eighth embodiment of the present invention.

FIG. 15 is a flow chart of a program showing a modified example of the means for determining the opposite phase of vibration at the left and right positions of the vehicle body used in the first to sixth embodiments.

FIG. 16 is a vibration waveform diagram at the left and right positions of the vehicle body.

[Explanation of symbols]

10A to 10D ... Shock absorbers, 12a to 12d
... hydraulic cylinders, 14a to 14d ... electromagnetic valves, 20 ...
Electric control device 21, 22 ... Vertical acceleration sensor 23,
24 ... band pass filter, 25 ... microcomputer, 27 ... vehicle speed sensor.

Claims (8)

[Claims] 1. A vehicle damping force control device for controlling a damping force changing mechanism, which is provided between a wheel and a vehicle body and is capable of changing a damping force with respect to vertical movement of the vehicle body, wherein horizontal positions are made different. First and second vibration sensors provided in at least two places of the vehicle body to detect vertical vibrations at the two places respectively, and a vertical direction of the vehicle body based on the vibrations detected by the first and second vibration sensors Damping force control means for controlling the damping force changing mechanism to increase the damping force with respect to the vertical movement of the vehicle body when the vibrations of the first and second vibration sensors are in phase relationship or A damping force for a vehicle, which is provided with a sensitivity control means for determining whether there is an inverse phase relationship and changing the control sensitivity of the damping force by the damping force control means according to the determination result. Control device. 2. A vehicle damping force control device for controlling a damping force changing mechanism, which is provided between a wheel and a vehicle body and is capable of changing the damping force with respect to vertical movement of the vehicle body, wherein the horizontal position is different. First and second vibration sensors provided in at least two places of the vehicle body and respectively detecting vertical vibrations at the two places, and the respective vibrations detected by the first and second vibration sensors are in phase relationship or opposite phase A determination unit that determines which of the relationships is present, and a vehicle body up and down determined based on the vibrations detected by the first and second vibration sensors when the determination units determine that the respective vibrations are in phase The damping force changing mechanism is controlled to increase the damping force with respect to the vertical movement of the vehicle body on the condition that the vibration level in the direction is greater than the first threshold value, and the vibrations are reversed in phase by the determining means. If the vibration level of the vehicle body is greater than the second threshold value that is smaller than the first threshold value, the damping force changing mechanism is controlled to increase the damping force with respect to the vertical movement of the vehicle body. A damping force control device for a vehicle is provided. 3. The vehicle damping force control device according to claim 2, further comprising: a vehicle speed sensor that detects a vehicle speed; and the first speed that changes according to the vehicle speed based on the vehicle speed detected by the vehicle speed sensor. A damping force control device for a vehicle, comprising: threshold value determining means for determining a threshold value. 4. The damping force control device for a vehicle according to claim 2, further comprising a vehicle speed sensor for detecting a vehicle speed, and the second speed varying according to the vehicle speed based on the vehicle speed detected by the vehicle speed sensor. A damping force control device for a vehicle, comprising: threshold value determining means for determining a threshold value. 5. A damping force control device for a vehicle for controlling a damping force changing mechanism, which is provided between a wheel and a vehicle body and is capable of changing the damping force for vertical movement of the vehicle body in at least three steps or more, in a horizontal direction. First and second vibration sensors provided in at least two places of the vehicle body whose positions are different from each other and respectively detecting vertical vibrations at the two places, and the respective vibrations detected by the first and second vibration sensors are Based on the vibrations detected by the first and second vibration sensors when the determination means determines whether each of the vibrations is in-phase or whether the vibrations are in-phase Each time the determined vibration level in the vertical direction of the vehicle body becomes larger than each of the plurality of sequentially increasing threshold values of the first set, the damping force changing mechanism is controlled to sequentially increase the damping force with respect to the vertical movement of the vehicle body. The damping force changing mechanism is controlled every time when the vibration level of the vehicle body becomes larger than each of a plurality of sequentially increasing threshold values of the second set when the vibration is determined to be in the opposite phase by the determining means. A damping force control means for sequentially increasing the damping force with respect to the vertical movement of the vehicle body and setting the minimum threshold value of the first set larger than the minimum threshold value of the second set. A vehicle damping force control device. 6. The damping force control device for a vehicle according to claim 5, wherein a change width of the plurality of threshold values of the first set is smaller than a change width of the plurality of threshold values of the second set. A damping force control device for a vehicle characterized by the above. 7. A vehicle damping force control device for controlling a damping force changing mechanism, which is provided between a wheel and a vehicle body and is capable of changing a damping force with respect to a vertical movement of the vehicle body, wherein horizontal positions are made different from each other. First and second vibration sensors provided in at least two places of the vehicle body and respectively detecting vertical vibrations at the two places, and the respective vibrations detected by the first and second vibration sensors are in phase relationship or opposite phase A determination unit that determines which of the relationships is present, and a smaller vibration of the respective vibrations detected by the first and second vibration sensors when the determination unit determines that the respective vibrations are in phase On the condition that the level is larger than a predetermined value, the damping force changing mechanism is controlled to increase the damping force with respect to the vertical movement of the vehicle body, and the determination means determines that each vibration is in the opposite phase. The damping force changing mechanism is controlled under the condition that the larger vibration level of the respective vibrations detected by the first and second vibration sensors is larger than the predetermined value, and the damping force with respect to the vertical movement of the vehicle body is reduced. A damping force control device for a vehicle, comprising: a damping force control means for increasing the damping force control means. 8. A vehicle damping force control device for controlling a damping force changing mechanism, which is provided between a wheel and a vehicle body and is capable of changing a damping force with respect to vertical movement of the vehicle body, wherein horizontal positions are made different from each other. First and second vibration sensors provided in at least two places of the vehicle body and respectively detecting vertical vibrations at the two places, and a level difference between the respective vibrations detected by the first and second vibration sensors are calculated. A calculating means and a damping force control means for controlling the damping force changing mechanism to increase the damping force with respect to the vertical movement of the vehicle body when the level difference calculated by the calculating means is larger than a predetermined value are provided. Vehicle damping force control device.