JPH08324221A - Suspension device for vehicle - Google Patents

Abstract

PURPOSE: To secure comfort to ride in, and excellently correct a course to a cross wind by setting a spring constant of a spring mechanism large when cross-wind speed is large. CONSTITUTION: A vertical acceleration sensor 61 detects and outputs vertical directional acceleration of a car body 21 to an absolute space. A differential pressure sensor 62 detects a difference in wind pressure by both cross winds by respectively inputting cross winds on both sides of the car body 21, and outputs a wind pressure difference P. First of all, a microcomputer 65 determines a spring constant Kg for vibration on the basis of the vertical directional acceleration. Next, when the wind pressure difference is not less than a prescribed value, a spring constant Kw for a cross wind is determined on the basis of a preset P-Kw map. When the wind pressure difference is not more than the prescribed value, the spring constant Kw for a cross wind is set in a minimum value. Next, the spring constant Kw for a cross wind and the spring constant Kg for vibration are compared with each other, and a larger spring constant is set as a target spring constant of a spring mechanism. Therefore, a course to a cross wind is excellently corrected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle in which a spring and a damper device are provided in parallel between an unsprung member and an unsprung member, and a spring mechanism whose spring constant can be changed is arranged in series with the damper device. The present invention relates to a suspension device for vehicles, and more particularly to a vehicle suspension device for changing and controlling a spring constant of the spring mechanism.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
A spring 14 that is provided between a lower arm (unsprung member) 12 and a vehicle body (sprung member) 13 connected to 1 to elastically support the vehicle body 13 with respect to the lower arm 12.
And the lower arm 12 is connected to the lower arm 12 at the lower end and the vehicle body 13 is connected to the lower arm 12 via the bush 15 at the upper end.
A vehicle suspension device including a damper device 16 for damping the vibration of the vehicle body 13 due to the elastic support of the vehicle is well known.

Further, as disclosed in, for example, Japanese Unexamined Patent Publication No. 5-286326 and Japanese Unexamined Patent Publication No. 61-188212, the damper device 16 is constructed so that its damping coefficient is electrically variably controlled. Incidentally, by detecting the vibration component in a specific frequency region (resonance frequency of the sprung member and the unsprung member) of the vehicle body 13 or by detecting the velocity of the crosswind received by the vehicle, the detected vibration component or crosswind velocity is detected. Is large, the damping coefficient of the damper device 16 is set to a large value to effectively suppress the posture change and vibration of the vehicle body 13, and
It is also known to ensure a good ride quality of the vehicle.

[0004]

Generally, when a vehicle receives a crosswind at a high speed, the course of the vehicle is disturbed, and therefore it is necessary to restore the course of the vehicle by quick correction steering. In this case, it is effective to use a damper device with a large damping coefficient or to set a large damping coefficient for the damper device as described above in order to secure a sufficient ground load on the tires and to suppress changes in the posture of the vehicle body. Is. However, if the damping coefficient of the damper device is always set to a large value, the spring constant of the bush 16 is usually large, so that the vehicle body 13 is always directly affected by the road surface and the riding comfort of the vehicle deteriorates. On the other hand, it is conceivable to reduce the spring constant of the bush 16, but in this case, the deflection of the bush 16 prevents the ground load of the tire from being sufficiently secured, and the damper device generates a damping force of a required magnitude. Since it disappears and there is a delay in its generation, it adversely affects the course correction of the vehicle due to crosswinds, and it becomes impossible to efficiently suppress vibration of the vehicle body at a specific frequency.

The present invention has been made to solve the above problems, and an object thereof is to ensure a good riding comfort of a vehicle and to satisfactorily correct the course of a vehicle against a side wind. To provide. In addition to this, it is another object of the invention to provide a vehicle suspension device capable of suppressing vibration of the vehicle body well.

[0006]

In order to achieve the above object, the first structural feature of the present invention is that the unsprung member (2
3) and the sprung member (21) between the damper device (4
Crosswind detection for detecting the speed of the crosswind received by the vehicle by configuring the vehicle suspension device so as to include a spring mechanism (50) that is arranged in series with (0) and is capable of changing the spring constant. Means (62 or 71-
74, 202, 204) and a spring constant control means (124 to 128, 1) for controlling the spring mechanism to set a large spring constant of the spring mechanism when the detected lateral wind velocity is high.
32, 136-140 or 204-208, 132, 1
36 to 140).

The second structural feature is that, in addition to the first structural feature, the damper device is configured such that its damping coefficient can be changed, and the damper is used when the detected lateral wind velocity is high. Damping coefficient control means (142 to 15) for controlling the device and setting a large damping coefficient of the damper device
2) is provided.

The third structural feature is that in addition to the first structural feature, a vibration detecting means (61, 63, 64) for detecting a vibration component of the sprung member in a specific frequency region.
And the spring constant control means is configured to set a large spring constant of the spring mechanism by controlling the spring mechanism when the detected vibration component or the lateral wind velocity is large (104 to 140). is there.

Furthermore, a fourth structural feature is that the third
In addition to the structural characteristics of the damper device, the damper device is configured to be capable of changing its damping coefficient, and when the detected vibration component or cross wind velocity is large, the damper device is controlled to set a large damping coefficient of the damper device. This is because the damping coefficient control means (142 to 152) is provided.

[0010]

According to the first structural feature described above,
When the vehicle receives a large cross wind, the cross wind detection means and the spring constant control means set the spring constant of the spring mechanism to a large value. Therefore, in this case, the spring mechanism is less likely to bend, a sufficient ground load for the tire is secured, and a damping force of a required magnitude is generated with good responsiveness by the damper device. Is quickly returned to the original state, and the posture change of the sprung member is also suppressed well. In addition, during normal operation, the spring constant of the spring mechanism can be kept small. In this case, since the spring mechanism is easily bent, the damping force generated by the damper device can be suppressed to be small even if there is road surface input. At the same time, the generation of the same damping force is delayed. As a result, the damping force due to the road surface input by the damper device is less likely to act on the sprung member as an exciting force, and the action is mitigated, so that the sprung member is less directly affected by the road surface. The ride comfort of the vehicle can be secured well.

Further, according to the second structural feature,
In addition to the function of the first structural feature, the damping coefficient control unit sets the damping coefficient of the damper device to be large when the cross wind velocity is high. Therefore, the correction steering with respect to the side wind can be performed more efficiently, and the riding comfort of the vehicle at the normal time can be better ensured.

Further, according to the third structural feature,
In addition to the function of the first structural feature, the spring constant of the spring mechanism is set to a large value by the vibration detection means and the spring constant control means even when the vibration component of the sprung member in the specific frequency region is large. . As a result, even when the sprung member vibrates in a specific frequency range, the damper device generates the damping force of a required magnitude and the delay in the generation of the damping force is reduced, so that the vibration of the vehicle body is reduced. Is effectively suppressed.

According to the fourth structural feature,
In addition to the action of the third structural feature, the damping coefficient control means sets the damping coefficient of the damper device to a large value when the vibration component or the lateral wind velocity of the sprung member in the specific frequency region is large. Therefore, the vibration of the sprung member can be suppressed and the correction steering against the crosswind can be performed more efficiently, and the riding comfort of the vehicle at normal times can be better ensured.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows the entire suspension device according to the present invention. The mechanical portion of this suspension device includes a vehicle body (sprung member) 21 and a vehicle body 2 at the inner end.
1 and a lower arm (unsprung member) 23 that supports the wheel 22 at the outer end and is arranged in parallel with the spring 31 and the damper device 40. The spring 31 elastically supports the vehicle body 21 with respect to the lower arm 23. The damper device 40 is configured so that the damping coefficient can be changed, and when the vehicle body 21 vibrates vertically, a damping force is generated to damp the vibration. Between the damper device 40 and the vehicle body 21, a spring mechanism 50 whose spring constant can be changed.
Are arranged in series with the damper device 40.

FIG. 2 shows an example of a mechanical portion of such a suspension device. The spring 31 is held at its lower end by a retainer 32 fixed on the outer peripheral surface of the cylinder 40a of the damper device 40, and at its upper end, the outer end of a fixed plate 33 fixed to the lower surface of the circular opening of the vehicle body 21. It is held on the lower surface via a bush 34.

The damper device 40 has a built-in damping force generating mechanism and a damping coefficient variable mechanism for variably controlling the damping coefficient of the mechanism, and is tiltably connected to the lower arm 23 at the lower end of the cylinder 40a. A piston rod 41 projects from the upper surface of the cylinder 40a, and a cylindrical sleeve 42 having a step is provided at the lower end of the rod 41.

A piston 43 for fluid-tightly partitioning the inside of the cylinder 40a into upper and lower oil chambers R1 and R2 is fixed on the outer circumference of the lower portion of the sleeve 42, and working oil (liquid) is stored in the upper and lower oil chambers R1 and R2. It is enclosed. The upper and lower oil chambers R1 and R2 communicate with each other via oil passages 43a and 43b provided in the piston 43, and oil passages 42a to 4a provided in the sleeve 42.
It is designed to communicate via 2d. The oil passages 42a to 42d, 43a, 43b form orifices. A free piston 4 is provided below the lower oil chamber R2.
4 defines a gas chamber R3, and the gas chamber R3 is divided into upper and lower oil chambers R1 by the amount of invasion of the piston rod 41 into the upper oil chamber R1 by the vertical movement of the free piston 44.
Absorbs volume changes of 1 and R2.

A leaf valve 45a that opens only downward is attached to the lower opening end of the oil passage 43a. The valve 45a extends from the upper oil chamber R1 to the lower oil chamber R2 only when the piston 43 moves upward. Allow movement of hydraulic oil. A leaf valve 4 that opens only upward at the upper open end of the oil passage 43b.
5b is assembled, and the valve 45b is provided from the lower oil chamber R2 to the upper oil chamber R only when the piston 43 moves downward.
Allow hydraulic oil to move to 1.

In the oil passage 42b of the sleeve 42, a cylindrical orifice member 46 having a taper portion 46a formed on the lower outer peripheral surface is housed so as to be vertically movable so as to face the peripheral wall of the oil passage 42b. The orifice member 46 is capable of continuously changing the throttle amount of the orifice formed between the tapered portion 46a and the peripheral wall of the oil passage 42b by the vertical movement thereof. In the damper device 40, the leaf valves 45a, 4a
A damping force is generated by the passage resistance to the hydraulic oil passing through 5b and the orifice, and
The damping coefficient is changed by changing the throttle amount of the orifice. Therefore, the sleeve 42, the piston 43, the leaf valves 45a and 45b, and the orifice member 46 form a damping force generating mechanism of the damper device 40.

The orifice member 46 is a drive rod 47.
Is fixed to the lower portion of the rod 47, and the upper end portion of the rod 47 is screwed to the nut 48 via a large number of balls. Nut 4
8 is a step motor 49 which constitutes an electric actuator.
Is driven to rotate, and the rotation causes the drive rod 47 and the orifice member 46 to move up and down. Therefore, the nut 48 and the step motor 49 constitute a damping coefficient variable mechanism.

The spring mechanism 50 incorporates a spring element and a spring constant variable mechanism for changing the spring constant of the spring element, and a movable plate 51 fixed to the upper end of the piston rod 41 in parallel with the fixed plate 33. Is equipped with.
Guide rods 52 are provided upright on the upper surface of the movable plate 51 at appropriate positions.
Slides on the inner peripheral surface of the through hole 33a provided in the fixed plate 33 to move the movable plate 51 up and down while keeping the movable plate 51 parallel to the fixed plate 33. In addition, the movable plate 51
On the upper surface of n (for example,
Several to ten or so coil springs 53 are erected and fixed at their lower ends. Each coil spring 5
The upper end of 3 is fixed to a stopper plate 54a provided at the lower end of the control rod 54, and the rod 54 slidably penetrates the inner peripheral surface of a through hole 33b provided in the fixed plate 33.

Each control rod 54 also penetrates a casing 55 fixed to the upper surface of the fixed plate 33 so as to be vertically movable. The casing 55 is the fixed plate 33.
An L-shaped frame 56 fixed to the upper surface of the is housed. A through hole 56a is formed in the horizontal portion of the frame 56, and the upper end portion of the control rod 54 is slidably passed through the hole 56a. Also, the casing 5
5 also includes a clutch bar 57 for pulling the control rod 54 laterally and an electromagnetic solenoid 58 for driving the bar 57 laterally.

The clutch bar 57 is supported by a support frame 59 fixed to the upper surface of the fixed plate 33 so as to be displaceable in the axial direction, and the tip end portion thereof is bent in a hook shape so as to engage with the intermediate portion of the control rod 54. Has become.
The clutch bar 57 is constantly urged to the right in the figure by springs 57a having both ends connected to the casing 55 and the clutch bar 57, respectively. Electromagnetic solenoid 5
8 is also fixed to the casing 55 and sucks the clutch bar 57 to the left in the figure in the energized state.

In the spring mechanism 50 thus constructed, when the electromagnetic solenoid 58 is de-energized, the clutch bar 57 is displaced to the right in FIG. 2 by the urging force of the spring 57a. In this state, the engagement between the tip end of the clutch bar 57 and the control rod 54 is released, and the rod 54 is fixed to the fixed plate 33 and the frame 5 until the stopper plate 54a abuts the fixed plate 33.
It can move up and down freely without being restricted by 6. Therefore, until the stopper plate 54a contacts the fixed plate 33, the coil spring 53 corresponding to the electromagnetic solenoid 58 that is not energized does not exert a spring action (the spring constant of the coil spring 53 is kept at "0"). .

On the other hand, when the electromagnetic solenoid 58 is energized,
The clutch bar 57 is displaced leftward in FIG.
The tip of the pulls the control rod 54 in the same direction. In this state, the control rod 54 is engaged with the inner peripheral surface of each of the through holes 33b and 56a of the clutch bar 57, the fixed plate 33, and the frame 56, and the rod 54 is equivalent to that fixed to the fixed plate 33. Become. Therefore, the coil spring 53 corresponding to the energized electromagnetic solenoid 58 exhibits a spring action, and its spring constant becomes a predetermined value k of the spring 53.

As described above, n coil springs 53 are provided, and each coil spring 53 can be selectively operated by energizing or de-energizing the electromagnetic solenoid 58 corresponding to each coil spring 53. m
When (m <n) electromagnetic solenoids 58 are energized, m
The individual coil springs 53 function, which is equivalent to inserting a spring element having a spring constant mk between the movable plate 51 (damper device 40) and the vehicle body 21. Therefore, in the spring mechanism 50, the spring constants of the spring elements composed of the n coil springs 53 provided between the damper device 40 and the vehicle body 21 are electrically controlled to 0, k, 2k, ... , Nk can be selected and set. Therefore, the spring constant changing mechanism that changes the spring constant of the spring element including the plurality of springs 53 includes the clutch bar 57 and the electromagnetic solenoid 58.

Next, the electric control device 60 for electrically controlling the mechanical portion of the suspension device will be described. The electric control device 60 includes a vertical acceleration sensor 61 and a differential pressure sensor 62.

The vertical acceleration sensor 61 is fixed to the vehicle body 21 or the fixed plate 33, detects vertical acceleration of the vehicle body 21 (spring member) with respect to an absolute space, and outputs a detection signal representing the same acceleration. To do. In addition, the detected acceleration represents an upward acceleration by a positive value and a downward acceleration by a negative value. The vertical acceleration sensor 61 includes a low pass filter 63 and a band pass filter 64.
Is connected. The low-pass filter 63 outputs the vibration component G1 of the vehicle body corresponding to the sprung resonance frequency (resonance frequency of the sprung member) by limiting and outputting the band of the detection signal indicating the acceleration to 2 Hz or less. The bandpass filter 64 outputs the vibration component G2 of the vehicle body corresponding to the unsprung resonance frequency (resonant frequency of the unsprung member) by limiting and outputting the band of the detection signal representing the acceleration within 9 to 13 Hz. To do. The differential pressure sensor 62 constitutes a lateral wind sensor for detecting the speed of the lateral wind received by the vehicle. The differential pressure sensor 62 inputs the lateral winds on both sides of the vehicle body 21 to detect the difference in the wind pressures due to both the lateral winds, and detects the difference in the wind pressures. A signal representing P is output.

The differential pressure sensor 62, the low pass filter 63 and the band pass filter 64 are connected to a microcomputer 65. Microcomputer 6
Reference numeral 5 repeatedly executes a program corresponding to the flowcharts of FIGS. 3 and 4 at predetermined short time intervals under the control of a built-in timer. By executing this program, the microcomputer 65 outputs a control signal for electrically controlling the damping coefficient of the damper device 40 and the spring constant of the spring mechanism 50 to the drive circuits 66 and 67. Drive circuit 66,
In response to the control signal, 67 drives the step motor 49 in the damper device 40 and the electromagnetic solenoid 58 in the spring mechanism 50, respectively.

Next, the operation of the suspension device configured as described above will be described with reference to a flow chart. The microcomputer 65 executes the program in step 100 of FIG. 3 in response to turning on of an ignition switch (not shown). Then, in step 102, the vibration components G1 and G2 and the wind pressure difference P are input from the low-pass filter 63, the band-pass filter 64, and the differential pressure sensor 62, respectively.

Next, through the processing of steps 104 to 122, the vibration spring constant Kg is set according to the magnitude of the vibration components G1 and G2 input. If the absolute values | G1 | and | G2 | of both vibration components G1 and G2 are greater than or equal to predetermined threshold values G10 and G20, respectively, the microcomputer 6
5 is a built-in G by the processing of steps 104 to 110.
With reference to the 1-K1 map (FIG. 5) and the G2-K2 map (FIG. 6), the first and second spring constants K1 and K2 corresponding to both vibration components G1 and G2 are determined. Note that Kmax1 and Kmax2 in FIGS. 5 and 6 have a relationship of Kmax1> Kmax2. After that, by the processing of steps 112, 114 and 120,
The larger value of the first and second spring constants K1 and K2 is set as the vibration spring constant Kg. If the absolute value | G1 | of the vibration component G1 is greater than or equal to the threshold value G10 and the absolute value | G2 | of the vibration component G2 is less than the threshold value G20, step 10
By the processes of 4 to 108 and 114, the first spring constant K1 determined by referring to the G1-K1 map is set as the vibration spring constant Kg. If the absolute value | G1 | of the vibration component G1 is less than the threshold value G10 and the absolute value | G2 | of the vibration component G2 is greater than or equal to the threshold value G20, the G2-K2 map is executed by the processing of steps 104 and 116-120. The second spring constant K2 determined with reference to is set as the vibration spring constant Kg. If the absolute values | G1 | and | G2 | of both vibration components G1 and G2 are less than the threshold values G10 and G20 respectively, steps 104 and 1
By the processing of 16 and 122, the minimum spring constant Kmin is set as the vibration spring constant Kg. The vibration spring constant Kg is immediately changed when the vibration spring constant Kg increases in the processing of steps 114, 120 and 122, but when it decreases, until a predetermined time elapses. Is not changed.

After setting the vibration spring constant Kg, the microcomputer 65 determines in step 124 whether the wind pressure difference P is a predetermined value P0 or more. If the side wind velocity received by the vehicle is large and the wind pressure difference P is equal to or larger than the predetermined value P0, it is determined to be "YES" in step 124 and the side wind is referred to in step 126 by referring to the P-Kw map (FIG. 7). The spring constant Kw for use is determined. If the lateral wind velocity received by the vehicle is small and the wind pressure difference P is less than the predetermined value P0, it is determined to be "NO" at step 124 and step 128 is performed.
The crosswind spring constant Kw is set to the minimum spring constant Kmin.

Next, in steps 130 to 134, the crosswind spring constant Kw and the vibration spring constant Kg are compared, and the larger spring constant of the two spring constants Kw and Kg is set as the target spring constant K. Set.

After setting the target spring constant K, step 1
The spring constant of the spring mechanism 50 is changed and controlled by the processes of 36 to 140. If the target spring constant K is equal to the current spring constant Know which represents the spring constant currently set in the spring mechanism 50, the program proceeds to step 142 based on the determination of “YES” in step 136. If the target spring constant K is not equal to the current spring constant Know, step 1
Based on the determination of “NO” in 36, step 138
At, a control signal indicating the target spring constant K is output to the drive circuit 67. The drive circuit 67 energizes the electromagnetic solenoids 58 corresponding to the target spring constant K in response to the control signal, and deenergizes the other electromagnetic solenoids 58. As a result, as described above, only the coil spring 53 corresponding to the energized electromagnetic solenoid 58 exerts the spring action, and the spring constant of the spring mechanism 50 is set to the target spring constant K. After the processing of step 138, the current spring constant Know is updated to the target spring constant in step 140, and the program proceeds to step 142.

At step 142, the current spring constant K
It is determined whether or not now (equal to the target spring constant K) is greater than or equal to a predetermined value Kmid (see FIG. 7). If the current spring constant Know is greater than or equal to the predetermined value Kmid, in step 142 “YE
Then, in step 144, the target damping coefficient C is set to a predetermined value Chigh indicating a large damping coefficient. If the current spring constant Know is less than the predetermined value Kmid, step 1
When it is determined to be "NO" at 42, the target damping coefficient C is set to a predetermined value Clow indicating a small value of the damping coefficient at step 146. Instead of the processing of these steps 142 to 146, the target damping coefficient C may be set to a value that continuously increases as the current spring constant Know increases.

After setting the target damping coefficient C, step 1
The damping coefficient of the damper device 40 is changed and controlled by the processing of 48 to 152. If the target damping coefficient C is equal to the current damping coefficient Cnow representing the damping coefficient currently set in the damper device 40, the program proceeds to step 154 based on the determination of “YES” in step 148. If the target damping coefficient C is not equal to the current damping coefficient Cnow, based on the determination of “NO” in step 148, step 1
At 50, a control signal representing the target damping coefficient C is supplied to the drive circuit 66.
Output to. The drive circuit 66 controls the rotational position of the step motor 49 of the damper device 40 to a position corresponding to the target damping coefficient C in response to the control signal. As a result, as described above, the damping coefficient of the damper device 40 is set to the target damping coefficient C. After the processing of step 150,
In step 152, the current damping coefficient Cnow is updated to the target damping coefficient, and the program proceeds to step 154.

As described above, according to the above-described embodiment, the vibration components G _{1 of} the vehicle body 21 corresponding to the specific frequency range (the sprung resonance frequency and the unsprung resonance frequency) are processed by the processes of steps 104 to 122. , G ₂ is large, the vibration spring constant Kg is set to a large value, and when the vibration components G ₁ and G ₂ are small, the vibration spring constant Kg is set to a small value. Further, by the processing of steps 124 to 128, the crosswind spring constant Kw is set to a large value when the crosswind velocity received by the vehicle (that is, the wind pressure difference P) is large, and the crosswind spring constant Kw is set to a small value when the crosswind velocity is small. Is set. Then, steps 130 to 134
The larger value of the spring constant Kg for vibration and the spring constant Kw for cross wind is set as the target spring constant K by the process of step No. 1, and the spring constant of the spring mechanism 50 sets the target spring constant K by the process of steps 136 to 140. Is set to. Therefore, when the vibration components of the sprung resonance frequency and the unsprung resonance frequency (specific frequency range) of the vehicle body 21 are large or the vehicle receives a strong cross wind, the spring constant of the spring mechanism 50 is set to a large value. As a result, the spring mechanism 50 is less likely to bend, a sufficient ground load for the tire is secured, and the damping force of the required magnitude is generated by the damper device 40 with good responsiveness. Therefore, the correction steering for the side wind is performed more efficiently, and the vibration of the vehicle body 21 is effectively suppressed.

On the other hand, in other cases, the spring mechanism 50
Since the spring constant of is set to be small and the spring mechanism 50 is easily bent, the damping force generated by the damper device 40 is suppressed to be small and the generation of the damping force is delayed even if there is a road surface input. . As a result, the damping force of the damper device 40 caused by the road surface input is less likely to act on the vehicle body 21 as an exciting force, and the action is alleviated. Therefore, the vehicle body 21 is less likely to be directly affected by the road surface, and the ride comfort of the vehicle is kept good.

When the spring constant of the spring mechanism 50 is set to a large value, the damping coefficient of the damper device 40 is also set to a large value Chigh by the processing of steps 142 to 152. Therefore, when the vibration components of the sprung resonance frequency and the unsprung resonance frequency of the vehicle body 21 are large or the vehicle receives a strong crosswind, the correction steering for the crosswind is performed more efficiently and the vibration of the vehicle body 21 is increased. Is suppressed more effectively. On the other hand, otherwise
Since the damping coefficient of the damper device 40 is set small, the ride comfort of the vehicle can be kept good. In particular, with respect to the vibration components of the vehicle body 21 (so-called rugged components) other than the vibration components of the sprung resonance frequency and the unsprung resonance frequency, the spring constant of the spring mechanism 50 and the damping coefficient of the damper device 40 are set small. Therefore, the ride comfort of the vehicle is kept good.

Next, a modified example of the means for detecting the lateral wind velocity in the above embodiment will be described. The electric control device 60 according to this modification includes a steering angle sensor 71, a differentiator 72, and a yaw rate sensor 73 instead of the differential pressure sensor 62, as shown by the broken line in FIG. The steering angle sensor 71 detects the steering angle θ of the steering wheel, and the differentiator 72 differentiates the steering angle θ to calculate the steering speed dθ / dt and outputs it to the microcomputer 65. Yaw rate sensor 7
3 detects the yaw rate γ generated in the vehicle body 21 and outputs it to the microcomputer 65. Further, in this modified example, the microcomputer 65 inputs the steering speed dθ / dt and the yaw rate γ instead of inputting the wind pressure difference P in step 102 of FIG. ~ 128 processing is shown in FIG.
The program changed to the processing of steps 202 to 208 is executed.

In this modification, the above-mentioned step 10 is performed.
The absolute value | dθ / dt | of the steering speed dθ / dt input in 2 is equal to or less than the minute value Δθ, and the yaw rate γ also input is the predetermined value γ.
When it is 0 or more, the lateral wind spring constant Kw is determined by the processing of steps 202 to 206 with reference to the γ-Kw map (FIG. 9) built in the microcomputer 65.
And at other times, steps 202, 204, 20
By the process of 8, the crosswind spring constant Kw is set to the minimum spring constant Kmin. This utilizes that the yaw rate γ is caused by the side wind received by the vehicle when the yaw rate γ is generated in the vehicle body 21 without the turning operation of the steering wheel. Other operations are the same as those in the above embodiment.

Further, the yaw rate sensor 73 is shown in FIG.
As indicated by the broken line in FIG. 1, the lateral acceleration sensor 74 for detecting the lateral acceleration Gy of the vehicle body 21 is substituted, and the step 1
Even if the yaw rate γ in the processing of 02, 204, 206 and the yaw rate γ in the map of FIG. 9 are replaced by the lateral acceleration Gy, the same result can be expected. This also utilizes that the yaw rate γ is caused by the side wind received by the vehicle when the yaw rate γ is generated in the vehicle body 21 without the turning operation of the steering wheel.

Further, in the above-described embodiment, the example in which the spring mechanism 50 is used in which the spring constant can be changed by selectively operating the plurality of coil springs 53 has been described. A spring mechanism having various structures can be used as long as it can be changed. For example, an elastic member such as rubber in which a liquid is sealed is interposed between the movable plate 51 and the fixed plate 33, and the elastic coefficient (spring constant) of the elastic member is changed by changing the amount of the sealed liquid. Stuff available. Also, cylinder 4
The gas pressure in the gas chamber R3 in 0a can be changed from the outside.

[Brief description of drawings]

FIG. 1 is a block diagram schematically showing an embodiment of a vehicle suspension device according to the present invention.

FIG. 2 is a partial cross-sectional view showing an example of a mechanical portion of the suspension device.

3 is a flowchart showing a first half of a program executed by the microcomputer of FIG.

FIG. 4 is a flowchart showing the latter half of the program.

FIG. 5: G1 provided in the microcomputer of FIG.
-Spring constant K1 for vibration component G1 in K1 map
It is a graph which shows the change characteristic of.

FIG. 6 G2-K2 provided in the same microcomputer
It is a graph which shows the change characteristic of the spring constant K2 with respect to the vibration component G2 in a map.

FIG. 7: P-Kw provided in the same microcomputer
It is a graph which shows the change characteristic of the spring constant Kw with respect to the wind pressure difference P in a map.

FIG. 8 is a flowchart showing a part of a program according to a modification of the embodiment.

FIG. 9: γ-K provided in the microcomputer
6 is a graph showing a change characteristic of a spring constant Kw with respect to a yaw rate γ in a w map.

FIG. 10 is a perspective view of a conventional vehicle suspension device.

[Explanation of symbols]

21 ... Vehicle body (sprung member), 22 ... Wheels, 23 ... Lower arm (unsprung member), 31 ... Spring, 40 ... Damper device, 40a ... Cylinder, 41 ... Piston rod, 42
... Sleeves 42a to 42d ... Oil passages (orifices), 4
3 ... Piston, 43a, 43b ... Oil passage (orifice),
45a, 45b ... Leaf valve, 46 ... Orifice member, 48 ... Nut, 49 ... Step motor, 50 ... Spring mechanism, 53 ... Coil spring, 54 ... Control rod, 57 ... Clutch bar, 58 ... Electromagnetic solenoid, 6
0 ... Electric control device, 61 ... Vertical acceleration sensor, 62 ... Differential pressure sensor, 63 ... Low pass filter, 64 ... Band pass filter, 65 ... Microcomputer, 71 ... Steering angle sensor, 72 ... Differentiator, 73 ... Yaw rate sensor, 74 ...
Lateral acceleration sensor.

Claims (4)

[Claims] 1. A spring for elastically supporting an unsprung member with respect to an unsprung member between an unsprung member and an unsprung member, and a vibration of a sprung member with respect to the unsprung member by generating a damping force. A vehicle suspension including a damper device that damps the damper in parallel, and a spring mechanism that is arranged in series with the damper device between the unsprung member and the unsprung member and that can change the spring constant. A device, a crosswind detecting means for detecting a speed of a crosswind received by the vehicle, and a spring constant control means for controlling the spring mechanism to set a large spring constant of the spring mechanism when the detected crosswind speed is high. A vehicle suspension device characterized by being provided with. 2. The vehicle suspension device according to claim 1, wherein the damper device is configured so that its damping coefficient can be changed, and the damper device is controlled when the detected cross wind velocity is high. A suspension device for a vehicle, comprising: damping coefficient control means for setting a large damping coefficient of the device. 3. A spring for elastically supporting the sprung member with respect to the unsprung member between the unsprung member and the unsprung member, and a vibration of the sprung member with respect to the unsprung member by generating a damping force. A vehicle suspension including a damper device that damps the damper in parallel, and a spring mechanism that is arranged in series with the damper device between the unsprung member and the unsprung member and that can change the spring constant. A device, a vibration detecting means for detecting a vibration component of a sprung member in a specific frequency region, a cross wind detecting means for detecting a velocity of a cross wind received by a vehicle, and a detector when the detected vibration component or cross wind velocity is large. A suspension device for a vehicle, comprising: spring constant control means for controlling a spring mechanism to set a large spring constant of the spring mechanism. 4. The vehicle suspension device according to claim 3, wherein the damper device is configured so that its damping coefficient can be changed, and the damper device is controlled when the detected vibration component or cross wind velocity is high. And a damping coefficient control means for setting a large damping coefficient of the damper device.