JPS611512A - Suspension control device - Google Patents

Abstract

PURPOSE:To improve the operating stability of a car by detecting two or more- step running and road surface states from steering, brake, vertical oscillation acceleration, and high speed signals and varying the spring constant of a bush to the large side in a suspension for the car. CONSTITUTION:A vertical oscillation acceleration signal G is input to the OR circuit 9 of a logic circuit 8 through a bandpass filter 5, a comparator 6, and a delay circuit 7 together with a steering signal S and a brake signal B, processed, and output to an OR circuit 10. A high speed state signal V is input to the OR circuit 10 and processed together with the output of the OR circuit 9. Running and road surface states are combined together in five steps and discriminated, and solenoids 41 and 42 are controlled through timers 12 and 13 so as to increase the spring constant of a bush at times other than good road, straight drive, no-brake, and low and intermediate speeds. As a result of this structure, comfortableness to drive a car and its operating stability can be ensured and improved.

Description

[Detailed description of the invention] (Technical field) The present invention relates to a suspension control device for one and both beams.

(Background technology) When the spring constant in the longitudinal direction of the vehicle body is set large for the radius rods used to mount the suspension links that make up the suspension of a vehicle, responsiveness during steering operations is improved. However, the ride quality will be slightly sacrificed, and on the other hand, if the spring constant is set to a small value, the ride comfort will be good, but the response delay during steering operation will be large, the toe change will be large depending on the suspension type, and the steering operation at high speeds will be affected. Safety tends to be sacrificed a little.

Therefore, it is conceivable to variably control the spring constant of the elastic bushing in the longitudinal direction of the vehicle body in two stages: large and small.

(Object of the Invention) An object of the present invention is to provide a vehicle in which the spring constant of an elastic bush provided on a mount portion of a suspension link in the longitudinal direction of the vehicle body is variably controlled in two or more stages of large and small. The spring constant can be automatically variably controlled to follow changes in braking conditions, driving conditions based on vehicle speed conditions, and road surface conditions, especially in relatively bad conditions such as steering operation conditions, braking conditions, high-speed driving conditions, and undulating conditions. To provide a suspension control device which increases a spring constant with consideration given to handling stability in any state where the vehicle is running on a road surface.

(Structure of the Invention) In order to achieve the above object, the present invention comprises a sensor for detecting the steering operation state, a sensor for detecting the brake state, a sensor for detecting the high speed state of the vehicle, and 47 vertical vibration acceleration sensors. A processing circuit that inputs these signals and outputs a signal of acceleration near the sprung resonance frequency of the vehicle body, and a control circuit that inputs these four types of signals and outputs signals of two or more levels depending on the driving and road surface conditions. and an actuator that receives the output signal and automatically switches the spring constant of the elastic bushing of the suspension link in the longitudinal direction of the vehicle body to two or more levels, large and small, and when any of the above-mentioned 4I4 detection signals is detected. The present invention is characterized by comprising a suspension control device that automatically variably controls the spring constant to a larger value.

(Embodiments) Below, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings.

Figure t55 is a perspective view showing an example of the suspension type.
(51) is a hub, (52) is a lower arm, (53) is a damper, and (54) is a radius rod, and the front end of the radius rod (54) is filled with fluid as shown in Figures 2 and 3. Boo Shu (20) is saved.

The bush (20) has an intermediate cylinder (23) arranged between an inner cylinder (21) through which the vehicle body side support bin is inserted and an outer cylinder (22) fixed to the front end of the radius rod (54). Then, the outer f:R (22) and the intermediate cylinder (23) are joined by the rubber walls (25) and ('6) of F which face each other in the radial direction, thereby connecting the outer M (22) and the intermediate cylinder. (23) Opposing fluid chambers (31) and (32) located in the longitudinal direction of the vehicle body are formed between them. The intermediate cylinder ( 23) is formed slightly toward one end in the axial direction.

Furthermore, ring plates (H) and (37) are fixed near both ends between the inner cylinder (21) and the intermediate cylinder (23), and both plates (3
e) A ring-shaped solenoid (4) is installed on the opposite surface of (37).
1) and (42), and both solenoids (41) and (4
2) A ring-shaped valve body (43) is provided between the inner cylinder (21) and the intermediate cylinder (23) so as to be slidable in the axial direction. Valve body (43)
has a box-shaped cross section, and in its axial direction there are passages (4
4) Provide... Further, both axial ends of the bushing (20) are provided with a rubber wall (2) that is integral with the rubber walls (25) and (2B).
7) and (2B), and the inside is filled with liquid.

In such a fluid-filled boot 7 (20), when one solenoid (41) is energized and the valve body (43) is attracted to it, the through holes (34) and (35) are in an open state. If the spring constant with respect to the longitudinal force direction of the vehicle body is small, and if the other solenoid I (42) is energized and the valve body (43) is attracted to it, the through holes (34) and (35) are Since the spring is closed as shown in the figure, the spring constant in the longitudinal direction of the vehicle body becomes large.

In addition, in the radial direction of the ring plates (3G) and (37), the solenoids (45) and (4G) and the permanent magnet (4
7).

If (48) is provided in a layered manner, the valve body (43) can be held by the permanent magnets (47) and (4B) even if the energization to the solenoid is stopped.

Next, the control circuit will be explained based on FIG.

(1) is a sensor (hereinafter referred to as G sensor) that detects the vertical vibration acceleration of the vehicle body corresponding to changes in road surface conditions and vehicle speed;
(2) is a sensor that detects the steering angle 1sI (hereinafter referred to as S sensor), (3) is a sensor that detects the ON/OFF state of the steering wheel and steering wheel (hereinafter referred to as B sensor), and (4) is a sensor that detects the high speed of the vehicle. This is a sensor (hereinafter referred to as V sensor) that detects the state.

The output signal port from the G sensor (1) is input to a band pass filter (5), which outputs a signal Gf with a frequency component near the sprung resonance frequency of the vehicle body, which is input to a comparator (8), and this output The signal at is so determined (Uct
When the signal is greater than or equal to +, the signal is set to [11, and when it is less than 01, the signal is input to the delay circuit (7).This input signal is given a certain delay time and is ORed in the logic circuit (8).
Input to circuit (9). Here, the delay circuit (7) is provided to delay the road surface with joints.

The output signal 1st from the S sensor (2) is set to a certain predetermined value 1s4 or more as a [+] signal, and less than a certain value as a 10) signal, and B
Output signal B from sensor (3) turns on the brake switch
The state is set to [11], and the OFF state is set to 10], and both of these signals are input to the OR circuit (9).

■The output signal V from the sensor (4) is set to a certain predetermined signal indicating a high-speed state (IfiV+ or above is a signal of ■1), less than is a signal of [0], and this signal and the signal of the OR circuit (9) are combined as follows. It is input to the OR circuit (10) of the stage.

And a spring constant [large] is applied to the output terminal of the OR circuit (10).
It outputs a signal [)l] representing
35) is energized to close the solenoid (12), the solenoid (43) is attracted to the solenoid (43), and the spring constant is automatically controlled to be large.

Also, the signal from the OR circuit (10) is branched and input to the N07 circuit (11), and the output terminal f of this N07 circuit (11) is
A signal [L] representing the spring constant [small] is output, and when this signal [L] is output, the solenoid (which opens the through holes (34) and (35) via the timer (13) 41
) is energized, the valve body (43) is attracted to it, and the spring constant is automatically controlled to [small j].

In 1- below, when the signal Of of the frequency component near the sprung mass resonance frequency of the vehicle body is greater than or equal to the set value Gf1, the steering angle (
The output signal of the logic circuit (8) is also set to [)l) in the case of a crash when No. 1+31 is the set value 1 or more, the brake signal B is in the ON state, and the medium speed V is in the high speed state of 71 or more.

The truth table is shown below along with the road surface and driving conditions, that is, the environmental conditions.

Next, each environmental condition will be explained.

First of all, condition 1 is driving straight on a relatively good road surface with almost no undulations, no brakes, and driving at low to medium speeds.
With emphasis on riding comfort, the spring constant of the bushing (20) in the longitudinal direction of the vehicle body is set to [small].

Condition 2 is when driving on a relatively bad road surface with large undulations, Condition 3 is a cornering condition, and Condition 4 is a braking condition, so in each case, the spring constant is set with emphasis on maneuverability. Set to [Large].

Furthermore, since condition 5 is for high-speed driving, the spring constant is also set to [large], with emphasis on the high-speed stability of the car.

Note that the variable spring constant elastic bushing is not limited to the one in the embodiment, and may be one in which the spring constant of the rubber itself of the rubber bushing is variable, and its actuator is not limited to a solenoid, but may also be hydraulically actuated. It is also possible to have three or more stages.

(Effects of the Invention) As described above, according to the suspension control device of the present invention, signals from the steering sensor, braking, vehicle speed sensor for high speed detection, and vertical vibration acceleration sensor of the vehicle body are inputted to control the vehicle body. A processing circuit that outputs acceleration signals near the sprung mass resonance frequency, a control circuit that inputs these signals and outputs signals of two or more levels depending on driving and road surface conditions, and a suspension link that receives the output signals. It consists of an actuator that switches the spring constant of the elastic boo and shoe in the longitudinal direction of the vehicle body into two or more stages, large and small. The spring constant of the body bushings in the longitudinal direction of the vehicle body can be automatically and variably controlled, especially in the case of steering operation, braking, high-speed driving, and driving on a relatively rough road surface with undulations. The spring constant can be automatically controlled to a larger value with emphasis on maneuverability.

[Brief explanation of drawings]

Fig. 1 is a blow diagram showing the control circuit, Fig. 2 is a sectional view of an example of an elastic bushing seen from the axial direction, Fig. 3 is a sectional view taken along the line m-m in Fig. 2, and Fig. 4 is FIG. 5 is a half-cut sectional view showing a modified example, and FIG. 5 is a perspective view showing an example of a suspension type. In addition, (20) in the drawing is a bony body bush, (25), (2
G) is a rubber wall, (3+), (32), (33)
is a fluid chamber, (34), (35) are through holes, (41),
(42) is an lenoid, (43) is a valve body, (54) is a suspension link, (5), (I() is a processing circuit, (
8) is a logic circuit.

Claims (1)

[Claims] In a vehicle suspension in which the spring constant of an elastic bush provided on the mount of a suspension link in the longitudinal direction of the vehicle body is variably controlled in two or more stages (large and small), a sensor that detects the steering operation state and a sensor that detects the brake state are used. A sensor that detects the vehicle's high-speed state, a sensor that detects the high-speed state of the vehicle, and a processing circuit that inputs signals from the vertical vibration acceleration sensor of the vehicle body and outputs a signal of acceleration near the sprung resonance frequency of the vehicle body. It is equipped with a control circuit that inputs a signal and outputs a signal of two or more stages depending on driving and road surface conditions, and an actuator that automatically switches the spring constant of the bush in response to the signal from the control circuit. 1. A suspension control device characterized in that the spring constant is automatically variably controlled to a larger value when any one of the detection signals is detected.