Automotive suspension system and shock absorber therefor

An automotive suspension system comprising:

• a shock absorber disposed between a vehicle body and a suspension member rotatably supporting a road wheel, said shock absorber including a cylinder tube connected to one of said vehicle body and said suspension member and defining an internal space, a piston disposed within said internal space for dividing said internal space into first and second chambers and connected to the other of said vehicle body and said suspension member for relative movement with respect to said cylinder tube, said first and second chambers being filled with a working fluid;
• a fluid communication means for establishing fluid communication between said first and second chambers with a limited fluid flow rate for generating a damping force against relative motion between said piston and said cylinder tube;
• a valve means associated with said fluid communication means for controlling flow restriction of said fluid communication means, said valve means being variable of flow restriction characteristics for varying damping characteristics of said shock absorber;
• a pressure sensor means for monitoring fluid pressure in said fluid pressure in said first chamber for producing a pressure indicative signal indicative of magnitude fluid pressure level higher than a predetermined initial pressure level;
• an actuating means, associated with said valve means and responsive to a control signal, for controlling said valve means for adjusting flow restriction characteristics according said said control signal;
• and
• a controlling means, receiving said pressure indicative signal, for deriving a variation rate of said pressure indicative signal and detecting said variation rate reaching a peak value for producing said control signal for increasing flow restriction for harder damping characteristics and detecting said variation rate decreasing across a predetermined softer suspension criterion for producing said control signal for decreasing flow restriction for softer damping characteristics.

An automotive suspension system comprising:

• a shock absorber disposed between a vehicle body and a suspension member rotatably supporting a road wheel, said shock absorber including a cylinder tube connected to one of said vehicle body and said suspension member and defining an internal space, a piston disposed within said internal space for dividing said internal space into first and second chambers and connected to the other of said vehicle body and said suspension member for relative movement with respect to said cylinder tube, said first and second chambers being filled with a working fluid;
• a fluid communication means for establishing fluid communication between said first and second chambers with a limited fluid flow rate for generating a damping force against relative motion between said piston and said cylinder tube;
• a first valve means associated with said fluid communication means for controlling flow restriction of said fluid communication means in a first direction of piston stroke, said valve means being variable of flow restriction characteristics for varying damping characteristics of said shock absorber;
• a second valve means associated with said fluid communication means for controlling flow restriction of said fluid communication means in a second direction of piston stroke opposite to said first piston stroke direction, said valve means being variable of flow restriction characteristics for varying damping characteristics of said shock absorber;
• a first piezoelectric means for monitoring fluid pressure in said fluid pressure in said first chamber during said second direction of piston stroke and producing a first pressure indicative signal indicative of magnitude fluid pressure level, said first piezoelectric element being responsive to a control signal for adjusting said flow restriction during said first direction of piston stroke;
• a second piezoelectric means for monitoring fluid pressure in said fluid pressure in said second chamber during said first direction of piston stroke and producing a second pressure indicative signal indicative of magnitude fluid pressure level, said second piezoelectric element being responsive to said control signal for adjusting said flow restriction during said second direction of piston stroke;
• and
• a controlling means, receiving said first and second pressure indicative signal, for selecting one of said first and second pressure indicative signal depending upon the piston stroke direction for deriving a variation rate of the selected one of first and second pressure indicative signals, and detecting said variation rate reaching a peak value for producing said control signal for harder damping characteristics and detecting said variation rate decreasing across a predetermined second value for producing said control signal for softer damping characteristics.

A variable damping force shock absorber system for an automotive suspension system, comprising:

• a cylinder tube connected to one of a vehicle body and a suspension member rotatably supporting a road wheel and defining an internal space;
• a piston disposed within said internal space for dividing said internal space into first and second chambers and connected to the other of said vehicle body and said suspension member for relative movement with respect to said cylinder tube, said first and second chambers being filled with a working fluid;
• a fluid communication means for establishing fluid communication between said first and second chambers with a limited fluid flow rate for generating a damping force against relative motion between said piston and said cylinder tube;
• a first valve means associated with said fluid communication means for controlling flow restriction of said fluid communication means in a first direction of piston stroke, said valve means being variable of flow restriction characteristics for varying damping characteristics of said shock absorber;
• a second valve means associated with said fluid communication means for controlling flow restriction of said fluid communication means in a second direction of piston stroke opposite to said first piston stroke direction, said valve means being variable of flow restriction characteristics for varying damping characteristics of said shock absorber;
• a first piezoelectric means for monitoring fluid pressure in said fluid pressure in said first chamber during said second direction of piston stroke and producing a first pressure indicative signal indicative of magnitude fluid pressure level, said first piezoelectric element being responsive to a control signal for adjusting said flow restriction during said first direction of piston stroke;
• a second piezoelectric means for monitoring fluid pressure in said fluid pressure in said second chamber during said first direction of piston stroke and producing a second pressure indicative signal indicative of magnitude fluid pressure level, said second piezoelectric element being responsive to said control signal for adjusting said flow restriction during said second direction of piston stroke;
• and
• said first and second piezoelectric means being connected to an externally provided controlling means, said controlling means receiving said first and second pressure indicative signal, for selecting one of said first and second pressure indicative signal depending upon the piston stroke direction for deriving a variation rate of the selected one of first and second pressure indicative signals, and detecting said variation rate reaching a peak value for producing said control signal for harder damping characteristics and detecting said variation rate decreasing across a predetermined second value for producing said control signal for softer damping characteristics.