DEVICE FOR THE CONTROL OF THE SUSPENSION SHOCK-ABSORBERS PARTICULARLY FOR MOTOR VEHICLES

Abstract: The device comprises sensor means (61) of the motor vehicle conditions connected to processing means (3) of the signals supplied by said sensor means (6) said processing means (3) being connected to actuator means (4, 5) of the response variations of the shock-absorbers.

Description: In the usual motor vehicles the shock-absorber response is predetermined duly calibrating the shock-absorber during its construction to guarantee a reasonable compromise between the vehicle stability and the comfort also in the most critical utilization conditions. In any case this calibration cannot be varied, while the vehicle utilization conditions might require shock-absorbers calibrated in a different way, depending on the type of road or on the type of drive. Devices are already known which can vary the shock-absorber response according to the user's wishes by an appropriate manoeuvre or automatically, according to certain vehicle utilization parameters, such as vehicle loading, speed, centrifugal force in curve, road surface. Such systems however have the inconvenience that they may be used not properly by the users who can choose an adjustment different from the one really useful in certain conditions, if not even dangerous, or they may be automatically controlled by parameters which only approximately represent the real need of a change in the calibration of the shock-absorbers. Purpose of the present invention is to realize a device for the automatic control of the suspension shock-absorbers, particularly for rotor vehicles, allowing the shock-absorbers to realize their damping effects between suspensions and motor vehicle body, only when it is necessary to guarantee the best riding comfort and the best road/pneuMatic adhesion The present invention attains the above mentioned purposes through a device for the control of the suspension shock-absorbers, particularly for motor vehicles, characterized in that it comprises sensor means of the motor vehicle conditions connected to processing means of the signals supplied by said sensor means, said processing means being connected to actuator p ans of the response variations of the shock-absorbers. The present invention will now be described with reference to the acccqianying drawings supplied only as non limiting examples, in which: Fig. 1 - represents a block diagram of the device object of the present invention; Fig. 2 - represents a block diagram of a detail of Fig. 1; Fig. 3 - represents a longitudinally sectioned shock-absorber. In Fig h with numeral 1 it is indicated a control panel for the selection of the desired type of control connected in point A to an electronic control unit 3 detailed in Fig. 2. The control unit is connected in point C with a power stage 4 corr nected to the valves 5 (e.g. of electromagnetic type) for the switching of the shock-absorber response, as it will be explained below. A detector of frequency and oscillation amplitude 6 is connected to the control unit 3 in point B. Fig. 2 represents a block diagram of the electronic control unit 3 of Fig. 1; with numeral 7 it is indicated an amplifier connected to the detector 6; the amplifier 7 is connected to a band-pass filter and to a related frequency/tension converter 8 connected in turn to a threshold discriminator 9 which is connected to a selector circuit 10. In Irs Fig. 3 with numeral 11 it is indicated a shock-absorber whose chambers 12 and 13 are connected by one of the valves 5 of Fig. 1. The functioning of the device object of the present invention is as follows. The driver operating on the keys of the control panel 1 decides if he wants a fixed (hard or soft) calibration or an automatically variable one, as a function of the road conditions. If he decides to act in a fixed way, he will operate keys R or M (hard or soft) of panel 1; in the first case (hard response) he will send to the control unit 3 signals which will activate the valves 5 to cut the communication between the chambers 12 and 13 of the shock-absorbers 11 and consequently will cause a hard response of same. If the driver operates key M (soft response), to the control unit 3 will be sent signals which will activate the valves 5 to open the above mentioned communication, so that the fluid flow through the upper and the lower part of the shock-absorbers 11 will be more quick (less braked) and the response of the shock-absorbers will be softer. If, on the contrary, it is wanted a system able to automatically vary the response of the shock-absorbers depending on the road conditions, it siust be operated key A of panel 1; by this way the control unit will be exclusively controlled by the signals supplied by the detector of frequency and oscillation amplitude 6. The signal coming from the detector 6 is amplified by the amplifier 7 and then filtered in the band from I to 20 Hz by band-pass filter 8 and converted fkulsl frequency into tension. The signal coming from block 8 reaches the threshold discriminator g which will control the power stage 4, so to close the valves 5 for a predetersined period of time (about 1 sec.) if the signal coming from block 8 exceeds a prefixed threshold stored in block 9 itself and corresponding to the shaking value of the motor vehicle, at which the passengers begin to feel car-sick or to be troubled by the oscillations in resonance with the oscillation frequencies of the vehicle body and/or wheels. As soon as the signals coming from detector 6 do not exceed any more the above mentioned threshold, the valves 5 will be reopened so that the shock-absorbers return to the soft response. Naturally by this way the damping effect of the shock-absorbers between suspensions and vehicle body takes place only when it is necessary to guarantee the best riding comfort and the best road adhesion. Always in the field of the present invention, the device can be varied, e.g. the accelerometric signals may be indicative ol the vertical accelerations of the wheel hubs, so to display anomalous oscillations and to prevent loss of adhesion; they could also be indicative of the braking, of the speed, of the acceleration in curve, etc. A simplified control unit could be used so that the response variations of the shock-absorbers are exclusively automatic; instead of accelerometers, it could be used proximity sensors. The soft calibration of the shock-absorbers could also be characterized by the almost complete absence of damping effect.

Claims: CLAIM I. Device for the control of the suspension shock-absorbers, particularly for motor vehicles, characterized in that it comprises sensor means of the motor vehicle conditions connected to processing means of the signals supplied by said sensor means, said processing means being connected to actuator means of the response variations of the shock-absorbers. 2. Device, according to claim I, characterized in that the sensor means of the motor vehicle conditions are detectors of frequency and amplitude oscillation. 3. Device according to claim 1, characterized in that the processing means are represented by an electronic control unit 3. 4. Device, according to claim 1, characterized in that the actuator leans are valves 5 or other devices able to operate in a relatively short tire. 5. Device, according to claim 1 and 3, characterized in that the electronic control unit 3 is constituted by an amplifier 7 connected to a unit 8 comprising a band-pass filter and a frequency/tension converter connected to a threshold discriminator 9 connected to a selector 10. 6. Device, according to claim 1 and 2, in which only the oscillations in resonance with the oscillation frequencies of the vehicle body and/or wheels are taken into account for modifying the shock-absorber calibration.

Inventors: EGIDI, CORRADO, FILIPPA, PAOLO, ROSSI, CARLO
Applicants: FIAT AUTO S.P.A.
Application year: 1985
Main classification: B60G17
IPC codes: B60G17, G01M17