JPS6053415A - Control device for car suspension - Google Patents

Abstract

PURPOSE:To prevent the swing back, hunting, etc. of a car after turning its direction by making the suspension characteristic hard in a specific running state such as turning, etc. and by keeping this hard state after the end of the specific running state for a prescribed period of time determined in acccordance with a speed of the car. CONSTITUTION:When the handle of a car is manipulated to turn the car while running, if a controller 10 judges, based on the output signals C and D from a handle angle sensor 11 and a car speed sensor 12, that the car is in a specific ruuning state exceeding the prescribed handle angle, drive signals A and B are outputted from the controller 10. These drive signals A and B are outputted for a longer prescribed time when running at high speed and for a shorter prescribed time when running at low speed. In this way, an electromagnetic valve operates to control open/close between a step motor 6, which changes the damping factor of a damper 3 of each suspension 2 in two steps (large and small), an air spring chamber 5 and an accumulator 8, and the suspension characteristic is changed and kept hard for a prescribed time period.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automobile suspension control device that variably controls suspension characteristics according to driving conditions.

(Prior art) The spring constant of the springs and the damping rate of the damper that make up the suspension of an automobile, that is, the suspension characteristics, significantly affect the ride comfort and body posture of the automobile. For example, if the suspension characteristics are hard, The ride comfort during driving will be poor, and if it is soft, the ride comfort will be good (f), but the so-called [1-ru phenomenon] where the outer part of the vehicle body sinks when turning becomes significant, and the vehicle body posture will become unstable. .

For such problems, for example, Japanese Patent Application Laid-Open No. 58-308
1 BN Publication discloses an invention related to ``vehicle anti-``1-small device.'' This is to operate the shock absorber's A refit control solenoid in accordance with the vehicle speed and steering angle to increase the damping rate of the shock absorber during cornering. According to this, during normal driving, the suspension characteristics are set to be soft to provide good ride comfort, and during cornering, the suspension characteristics are set to be hard to prevent roll of the vehicle body.

However, in this invention, the damping rate of the shock absorber is increased only while the roll of the vehicle body is detected from the vehicle speed and steering wheel angle, so the suspension characteristics become soft as soon as the steering wheel is turned after turning. Therefore, it is not possible to prevent the vehicle body from swinging back after the steering wheel is turned back and from hunting in one direction due to this.

(Object of the Invention) The present invention solves the above-mentioned drawbacks of conventional suspension control devices, and while ensuring good ride comfort by setting the suspension characteristic to Soft 1 during normal driving, for example, when turning When the vehicle is in a specific driving state such as when the vehicle is in a specific driving state, the suspension characteristics are made hard to stabilize the vehicle body posture, and this hard state is maintained for a predetermined period of time even after the end of the specific driving state. To effectively prevent swinging back, hunting, etc. caused by turning the steering wheel back.

In the special L''tDlll, by setting the hard state and holding time after the end of the above-mentioned specific driving state to be long at high speeds and short at low speeds, it is possible to reliably prevent swinging back after turning and hunting in one direction, which is particularly noticeable at high speeds. At the same time, it prevents deterioration of ride comfort caused by unnecessarily hardening the suspension characteristics for a long time at low speeds.

(Structure of the Invention) The suspension control device for an automobile according to the present invention is configured as follows in order to achieve the above object.

That is, the configuration includes a suspension with variable suspension characteristics such as a spring constant and a damping rate of a damper, and a specific running state detection means for detecting a specific running state of the vehicle, and a vehicle speed detection means for detecting the running speed of the vehicle. and receiving the outputs of these detection means, hardens the suspension characteristics of the suspension when in a specific driving state, and maintains this hard state for a predetermined period of time after the end of the specific driving state;
It also includes a control means that operates to maintain the hard state for a longer period of time at high speeds and a shorter period of time at low speeds. The specific running state detection means is, for example, a roll detection means for detecting roll of the vehicle body, and in this case, the suspension characteristics of the suspension are set to be hard from the start of roll due to turning until a predetermined time has elapsed after the roll has stopped. At the same time, the hard state retention time after the roll is stopped is longer at high speeds and shorter at low speeds.

(Example) Hereinafter, the present invention will be explained based on embodiments shown in the drawings.

As shown in FIG. 1, front, rear, left and right wheels 1...1 are provided with suspensions 2...2 for suspending the vehicle body. Each of these eggplant pensions 2...2 has a damper 3, a coil spring 4, and an air spring chamber 5, and the damper 3 is equipped with a step motor 6 that switches its damping rate in two stages, large and small. . Further, the air spring chamber 5 is connected to an accumulator 8 via a pipe 7, and the air spring chamber 5 and the accumulator 8 are connected to each other via a pipe 7.
A solenoid valve 9 is interposed between the two to communicate and cut off the two.
By opening and closing the electromagnetic valve 9, the air suspension acting as a spring is increased or decreased, so that the spring constant of the air spring can be switched between two levels, large and small.

On the other hand, each suspension 2...2 is equipped with a controller 10 that sends drive signals Δ and B to the step motor 6 and solenoid valve 9.
0 is a steering wheel angle sensor 1 that detects the steering angle of the steering wheel.
A signal C from a vehicle speed sensor 12 and a signal from a vehicle speed sensor 12 that detects the traveling speed of the vehicle are inputted.

Here, the specific structure of the suspension 2 will be explained with reference to FIG.
The bracket 2 is movable up and down relative to the bracket 2.
At the same time, the lower end of the upper case 22 and the upper end of the lower case 24 are connected through the rolling diaphragm 25, and both cases are connected to each other through the rolling diaphragm 25. 22. Seal member 26 is inside 24
The upper case 22 is partitioned into a sealed air spring chamber 5. The air spring chamber 5 is connected to the accumulator 8 via the pipe 7 and the solenoid valve 9 as described above, and is connected to the upper case 22 and the lower case 24.
A spring receiver member 27, 28 is fixedly attached to each of the coil springs 4, and the above-mentioned coil spring 4 is mounted thereon.

The lower case 24 is composed of an outer cylinder 29 and an inner cylinder 30, and a piston rod 31 suspended from the upper case 22 is inserted into the inner cylinder 30 so as to be vertically slidable. The interior of the inner cylinder 30 is partitioned into an upper oil chamber 33 and a lower oil chamber 34 by a main valve 32 . Further, a bottom valve 35 is provided at the lower end of the inner cylinder 30, and a space between the inner fiI 30 and the outer cylinder 29 is a reservoir chamber 36.

Further, the main valve 32 is connected from the upper oil chamber 33 to the lower oil chamber 34 by a check valve 37, as shown in an enlarged view in FIG.
The extension side orifice 38 is configured to allow the working fluid to pass only to the side, and the contraction side orifice 40 is configured to allow the working fluid to pass only from the lower oil chamber 34 to the upper oil chamber 33 side by the check valve 39. It also has an orifice valve 43 consisting of a sleeve 41 and a valve body 42.

This orifice valve 43 is rotated by the step motor 6 shown in FIGS. 1 and 2 via the controller 1 through which the valve body 42 is inserted into the piston rod 31 and the roll rod 44.
As shown in the figure, the through hole 41a in the sleeve 41 and the valve body 4
The upper oil chamber 33 and the lower oil chamber 34 are communicated with each other when the through holes 42a of the upper oil chamber 33 and the lower oil chamber 34 are aligned. The damper 3, which is constituted by the upper oil chamber 33, the lower oil chamber 34, and the main valve 32, is connected to this by the operation of the step motor 6, and the compartments 33 and 34 are communicated only by the A refit 38 or 40. It is switched between a state with a large damping rate and a state with a small damping rate communicated by the orifice valve 43 in addition to these states.

On the other hand, the controller 10 shown in FIG. 1 is configured as shown in FIG. 4. That is, the controller 10 has a roll determination circuit 51 which outputs a roll signal E at rHJ level when the signal C from the steering wheel angle sensor 11 is input and determines the roll of the vehicle body, and the roll signal E is inputted thereto. A first timer circuit 52 and a second timer circuit 53,
A vehicle speed determination circuit 54 receives a signal from the vehicle speed sensor 12 and outputs a signal E at the rl-(J level) when the vehicle is at high speed.
and has. Above 1. The second timer circuit 52゜531 is a circuit having an off-delay function, as shown in Fig. 5(b).
As shown in (d), at the same time as the roll signal E is input from the roll determination circuit 51, the signal G1. G
2 respectively, but when the input of signal E is stopped, the delay time T1 . After T2 (T+>T2), the signal G1.
Stop G2 output. Then, the output signal G1 of the first timer circuit 52 and the output signal F of the vehicle speed determination circuit 54 are input to the first AND circuit 55, and the second timer circuit 5
The output signal G2 of No. 3 and the signal F' obtained by inverting the output signal of the vehicle speed determination circuit 54 by the inverter 56 are combined into a second AND.
The first . The output signal of the second AND circuit 55 and 57 is @1.

(2) is input to the amplifier circuit 59 via the OR circuit 58, and when any one of the above signals 1" and (2) is at the "T1" level, the amplifier circuit 59 supplies the signals to the step motors 6 and the solenoid valves 9. Drive signals A and B are output. Here, the drive signal A drives the step motor 6 so that the orifice valve 43 in the damper 3 closes, and the drive signal B moves the solenoid valve 9 111. Therefore, these signals A, B
At the time of output, the damping rate of the damper and the spring constant of the spring are increased significantly, and the suspension characteristics of the suspension 2 become hard.

The roll determination circuit 51 is configured by, for example, a microphone monitor as shown in FIG. That is, it is comprised of an arithmetic circuit 63 into which the signal C from the steering wheel angle sensor 11 is manually inputted via an amplifier 61 and a Δ-reconverter 62, and a memory circuit 64 connected to the arithmetic circuit 63. The numbing circuit 63 is 70-chi 11-1 in FIG.
According to ~, first, the current steering wheel angle θ is determined by the signal C.
(step S1), and this handle angle θ
And memory f! The current weighted average value θ0 is determined from the weighted average value Oo' of the steering wheel angles up to the previous time determined by the previous calculation stored in the storage 64 (step S2);
After that, this average value θ0 is compared with the tc steering wheel angle θ read this time, and when the difference 1θ−θo1 exceeds the fixed value R, the above-mentioned first. Step S3. Outputs the roll signal E to the second timer circuits 52 and 53. S4). Here, in the example shown in Fig. 7, when calculating the current average value θ0 from the previous average value θ0' and the current reading handle angle θ, in order to make the weights of both Oo' and θ different, A constant 1 (greater than 1) is used.

Next, the operation of the above embodiment will be explained.

First, during normal straight-ahead driving, the controller 10
B is not outputted to the drive signal that hardens the suspension characteristics to the step motor 6 and solenoid valve 9 of each suspension 2...2. Therefore, in each suspension 2, the orifice valve 43 connected to the damper 3 connects the upper oil chamber 33 and the upper oil chamber 34 as shown in FIG. 8 are in communication with each other, and both the damper and the spring are connected to the soft 1. On the other hand, the platform that rotates the steering wheel to turn the car uses the steering wheel angle sensor 1.
In the roll determination circuit 51 of the controller 10 to which the signal C is input from 1 to 1, the arithmetic circuit 63 operates according to the flowchart 1 to 1 in FIG. 7 to first calculate the weighted average value θ0 of the steering wheel angle.

As shown in FIG. 5(a), this average value θ0 changes smoothly and with a delay with respect to changes in the steering wheel angle θ. Then, the steering wheel angle θ at that time and the average 1ifi up to that point
When the difference from Oo exceeds a certain value R, in other words, when the roll of the vehicle body is determined, the first . The roll signal E is output to the second timer circuits 52 and 53, and along with this, the first timer circuit 52. The second timer circuit 52,53 is connected to the first timer circuit 52,53. Signal G is applied to the gates of the second AND circuits 55 and 57, respectively.1. 'Output G2. At this time, the first. The other goo 1~ of the second AND circuit 55.57 receives the signal 1' 11 at high speed from the vehicle speed determination circuit 54.
Since the signal F, which is at the J level, and the signal F', which is at the J level of "1" at low speeds, are each separated, at high speeds, the same signal signal as the output signal G1 of the first timer circuit 52 is output from the first AND circuit 55-. 1 is output, and at low speed, the 2nd. The AND circuit 57 outputs the same signal (2) as the output signal G2 of the second timer circuit 53. In that case, 1. Output signals Gt, G of the second timer circuit 52゜53
As shown in FIGS. 5(b) to 5(d), the output signal G1- of the first timer circuit 52 rises at the same time as the input signal E turns ON, but the output signal G1- of the first timer circuit 52 takes a relatively long time after the input signal QE turns OFF. After the time T1 has elapsed, the output j signal G2 of the second timer circuit 53 is turned off after a relatively short time T2 has elapsed.

As a result, at high speed, the output signal l of the first AND circuit 55
Based on this, drive signals @A and B are output from the five amplifier circuits to the step motor 6 and the solenoid valve 9 from the time when the roll is determined until a relatively long time T1 has elapsed after the end of the determination. Sometimes, based on the output signal I of the second AND circuit 57, the drive signals A and B are outputted from when the roll is determined until a relatively short time T2 has elapsed after the end of the determination.

In this way, at both high speeds and low speeds, when turning, the roll is determined simultaneously with each 1 nospension 2.
. . 2, the orifice valve 43 of the damper 3 is closed, the air spring chamber 5 and the damper 8 are shut off, and the suspension characteristics are made hard, and even after the roll determination is completed, the set time is maintained. The hard state is maintained only during 1-1 or T2, and swinging back after the roll is stopped is prevented. In this case, at high speeds, the above-mentioned hard state holding time T1 is long, which prevents swaying back and hunting is reliably prevented, especially at high speeds, and at low speeds, hard state holding time T2 is short, so swinging back is prevented. The time required to sacrifice ride comfort for the 1st floor is set to be the minimum amount of time required.

Here, in this embodiment, the roll determination circuit 51 of the controller 10 rolls when the difference between the steering wheel angle O and the average value θO of the steering wheel angle up to the point in time exceeds a certain value R@. Since the configuration is configured to determine the rotation of the steering wheel, the roll signal E is not outputted in a complicated manner due to rotation of the steering wheel with a degree of play, and if the steering wheel angle θ is maintained at a constant angle and shifts to a steady turning state Output of the signal E is stopped. In other words, the roll signal E is output only when the steering wheel angle changes sharply above a certain level and the vehicle body is actually rolling. The intermediate suspension is set to hard, and when the above-mentioned time T1 or T2 elapses after transitioning to a steady turning state, it is returned to soft again. Then, as shown in Fig. 5, when returning from a steady turning state to a straight running state, the roll signal E is output again when the steering wheel angle changes sharply over a certain level. During the subsequent predetermined time T1 or T2, the lease becomes hard again.

The formula for calculating the average value θ0 of the steering wheel angle θ is as follows:
In addition to the calculation formula shown in flowchart 11-1 of FIG. Among the N values of the steering wheel angle θn up to the point in time,
The average value of M values immediately before the point in time, that is, 00−(Σθ
n)/M, n=N-M+1, etc. may be used.

Alternatively, the controller 0 may be configured with an analog circuit 51' as shown in FIG. 8, as shown in FIG. θ is sent to a differential amplifier 72 via an amplifier 71, one directly and the other by an integrating circuit 73 as shown in FIG.
> is input as the average value θ0, and the difference (0-60) between the two is output from the differential amplifier 72. Then, this difference is input to the comparator 74 and compared with the constant voltage R,
The configuration is such that the roll signal E is output when the difference (θ-θ0) is larger than R. Even with this configuration,
The same effect as in the above embodiment can be obtained.

In the above embodiments, the suspension characteristics are controlled for both the spring and the damper, but only one of them is controlled 1]'? You can also make it so that
Alternatively, the control may be performed only on the one-side suspension of the outer wheel when turning.

Furthermore, the hard state holding time may be changed in three or more steps or steplessly depending on the vehicle speed.

(Effects of the Invention) As described above, according to the present invention, 4. the suspension characteristics of the eggplant suspension are made harder in specific driving conditions such as when turning, and
This hard state is maintained for a predetermined period of time even after the end of a specific driving state, and this hard state is held for a long time at high speeds and short at low speeds, so that, for example, the vehicle body rolls due to turning, its shaking back, etc. Hunting of the vehicle body in one direction accompanying these is reliably prevented at high speeds, where it becomes especially noticeable, and without unnecessarily sacrificing ride comfort at low speeds, and the posture of the vehicle body is stabilized.

The above-mentioned embodiment is an example in which the suspension characteristics are returned to -H soft when turning to a steady turning state, but this steady turning state is also determined to be a roll state, and the vehicle is returned to a straight-ahead running state. When returning, a hard state retention time may be set so that the state does not return to the software state. Furthermore, the present invention is applicable not only to situations during turning, but also to other specific driving situations in which similar problems regarding the posture of the vehicle body occur.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and Fig. 1 is a control system diagram, Fig. 2 is a vertical cross-sectional view showing the specific configuration of the lease pension, Fig. 3 is an enlarged view of the main parts, and Fig. 4 is a diagram of the control system. Conte [
Figure 5 is a time chart showing the operation, Figure 6 is a block diagram showing a specific example of the roll determination circuit in the controller I-roller, and Figure 7 is a block diagram showing the configuration of the controller I-roller.
The figure is a flowchart without showing the operation of the determination circuit, and FIG. 8 is a circuit diagram C showing another specific example of the roll determination circuit. 2... eggplant pension, 10... control means (]n]
・Roller), 11,51.51'...Specific running state detection means (11...Handle angle sensor, 51.51'
. . . roll judgment circuit), 12 . . . vehicle speed detection means (
Vehicle speed sensor) Fig. 5 Fig. 6 Fig. 7 Fig. 94- Fig. 8

Claims (2)

[Claims] (1) Variable suspension characteristics ii + Jt1
1, the suspension control device includes a specific running state detection means for detecting a specific running state of the vehicle, a vehicle speed detection means for detecting the running speed of the vehicle, and a suspension control device that receives the outputs of these detection means and detects when the vehicle is in the specific running state. At times, the suspension characteristics of the suspension are made hard, and this hard state is held for a predetermined time after the end of the specific driving state, and the time for which this hard state is held is made longer at high speeds and shortened at low speeds. 1. An automobile eggplant pension control device, characterized in that it is equipped with a control means. (2) The automobile suspension control device according to claim 1, wherein the specific driving state detection means is a roll detection means for detecting roll of the vehicle body.