Proportioning valve assembly for an actively controlled suspension system
First Claim
1. A proportioning valve assembly disposed between a pressurized fluid source and a hydraulic cylinder for adjusting fluid pressure in a working chamber in said hydraulic cylinder, said proportioning valve assembly operating in a first mode in response to vibration energy for absorbing vibration energy for maintaining said fluid pressure in said working chamber and in a second mode for adjusting said fluid pressure in said working fluid for varying characteristics of said hydraulic cylinder, comprising:
- a valve housing defining a first port connected to a pressurized working fluid source to receive pressurized working fluid therefrom, a second port connected to said pressurized working fluid source for returning the working fluid thereto, and a third port connected to a work for fluid communication therewith for adjusting working fluid pressure in said work;
a first valve means having one end facing a first chamber to be exerted a pilot pressure representative of a predetermined pressure in said hydraulic cylinder and the other end facing a second chamber to be exerted a feedback pressure which is fed back from said third port, said first valve body being movable according to pressure difference between pilot pressure and said feedback pressure for selectively establishing fluid communication between said first, second and third ports of said valve housing, said first valve body solely operative in response to a pressure difference between said pilot pressure and said feedback pressure for maintaining said fluid pressure in said working chamber constant at the pressure of said first chamber in said first mode;
a fluid path means defining a fluid path extending from said first port to said first chamber and from said first chamber to said second port;
a second valve means associated with said fluid path for providing flow restriction at a predetermined magnitude for generating said pilot pressure within said first chamber, said second valve means being operative in said second mode for adjusting said pilot pressure, and said second valve means including an electrically operable actuator means receiving a control signal to drive a valve member at a position corresponding to a value of said control signal for adjusting said pilot pressure at a pressure corresponding to said control signal value; and
an electric circuit means for supplying said control signal to said actuator of said second valve means, said electric circuit means including means for causing phase advance compensating lag in said first valve means in response to a variation of said pilot pressure in said second mode operation.
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Accused Products
Abstract
A proportioning valve assembly employs an electromagnetic acuator, such as a proportioning solenoid, associated with a driver circuit. The driver circuit is provided a lead phase circuit for providing a lead phase in supplying a supply current for controlling the valve position of the proportioning valve. Providing appropriate lead time reduces necessity of high gain in attitude change suppression mode operation. Therefore, the response characteristics in pressure adjustment in the shock absorbing mode operation, can be prevented from falling an excessive level.
18 Citations
18 Claims
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1. A proportioning valve assembly disposed between a pressurized fluid source and a hydraulic cylinder for adjusting fluid pressure in a working chamber in said hydraulic cylinder, said proportioning valve assembly operating in a first mode in response to vibration energy for absorbing vibration energy for maintaining said fluid pressure in said working chamber and in a second mode for adjusting said fluid pressure in said working fluid for varying characteristics of said hydraulic cylinder, comprising:
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a valve housing defining a first port connected to a pressurized working fluid source to receive pressurized working fluid therefrom, a second port connected to said pressurized working fluid source for returning the working fluid thereto, and a third port connected to a work for fluid communication therewith for adjusting working fluid pressure in said work; a first valve means having one end facing a first chamber to be exerted a pilot pressure representative of a predetermined pressure in said hydraulic cylinder and the other end facing a second chamber to be exerted a feedback pressure which is fed back from said third port, said first valve body being movable according to pressure difference between pilot pressure and said feedback pressure for selectively establishing fluid communication between said first, second and third ports of said valve housing, said first valve body solely operative in response to a pressure difference between said pilot pressure and said feedback pressure for maintaining said fluid pressure in said working chamber constant at the pressure of said first chamber in said first mode; a fluid path means defining a fluid path extending from said first port to said first chamber and from said first chamber to said second port; a second valve means associated with said fluid path for providing flow restriction at a predetermined magnitude for generating said pilot pressure within said first chamber, said second valve means being operative in said second mode for adjusting said pilot pressure, and said second valve means including an electrically operable actuator means receiving a control signal to drive a valve member at a position corresponding to a value of said control signal for adjusting said pilot pressure at a pressure corresponding to said control signal value; and an electric circuit means for supplying said control signal to said actuator of said second valve means, said electric circuit means including means for causing phase advance compensating lag in said first valve means in response to a variation of said pilot pressure in said second mode operation. - View Dependent Claims (2, 3, 4)
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5. A proportioning valve assembly comprising:
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a valve housing defining a first port connected to a pressurized working fluid source to receive pressurized working fluid therefrom, a second port connected to said pressurized working fluid source for returning the working fluid thereto, and a third port connected to hydraulic cylinder for fluid communication therewith for adjusting working fluid pressure in said hydraulic cylinder; a first valve body having one end facing a first chamber to be exerted a pilot pressure representative of a desired pressure in said hydraulic cylinder and the other end facing a second chamber to be exerted a feedback pressure which is fed back from said third port, said first valve body being movable according to pressure difference between pilot pressure and said feedback pressure for selectively establishing fluid communication between said first, second and third ports of said valve housing; a fluid path means defining a fluid path extending from said first port to said first chamber and from said first chamber to said second port; a second valve means associated with said fluid path for providing flow restriction at a predetermined magnitude for generating said pilot pressure within said first chamber; a first flow restricting means providing in a fluid path connecting said third port and said feedback chamber for restricting fluid flow therethrough; and a driver circuit connected to said second valve for driving said second valve means to a desired valve position for adjusting the valve pressure, said driver circuit including a circuit component for compensating phase delay caused by said flow restriction by said first flow restricting means. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An actively controlled suspension system comprising:
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a hydraulic cylinder disposed between a vehicular body and a suspension member rotatably supporting a vehicular wheel, said hydraulic cylinder defining an internal space with a piston disposed therein, said piston being attached to said vehiclar body and said suspension member via a piston rod, said piston being thrustingly received into a working chamber, said working chamber being variable of pressure for varying suspension characteristics; a hydraulic circuit connecting a pressurized working fluid source to said working chamber, said hydraulic circuit including a first line connected to an outlet of said pressurized working fluid source, a second line connected to an inlet of said pressurized working fluid source for returning working fluid therethrough, and a third line connected to said working chamber; a proportioning valve assembly disposed between a pressurized fluid source and an hydraulic cylinder for adjusting fluid pressure in a working chamber in said hydraulic cylinder, said proportioning valve assembly operating in a first mode in response to vibration energy for absorbing vibration energy for maintaining said fluid pressure in said working chamber and in a second mode for adjusting said fluid pressure in said working fluid for varying characteristics of said hydraulic cylinder, comprising; a valve housing defining a first port connected to a pressurized working fluid source to receive pressurized working fluid therefrom, a second port connected to said pressurized working fluid source for returning the working fluid thereto, and a third port connected to a hydraulic cylinder for fluid communication therewith for adjusting working fluid pressure in said hydraulic cylinder; a first valve means having one end facing a first chamber to be exerted a pilot pressure representative of a desired pressure in said hydraulic cylinder, and the other end facing a second chamber to be exerted a feedback pressure which is fed back from said third port, said first valve body being movable according to a pressure difference between said pilot pressure and said feedback pressure for selectively establishing fluid communication between said first, second and third ports of said valve housing, said first, second and third ports of said valve housing, said first valve body solely operative in response to a pressure difference between said pilot pressure and said feedback pressure for maintaining said fluid pressure in said working chamber constant at the pressure of said first chamber in said first mode; a fluid path means defining a fluid path extending from said first port to said first chamber and from said first chamber to said second port; a second valve means associated with said fluid path for providing flow restriction at a predetermined magnitude for generating said pilot pressure within said first chamber, said second valve means being operative in said second mode for adjusting said pilot pressure, and said second valve means including an electrically operable actuator means receiving a control signal to drive a valve member at a position corresponding to a value of said control signal for adjusting said pilot pressure at a pressure corresponding to said control signal value; and an electric circuit means for supplying said control signal to said actuator of said second valve means, said electric circuit means including means for causing phase advance compensating lag in said first valve means in response to variations of said pilot pressure in said second mode operation; an actuator associated with said second valve means for controlling position of said second valve means for adjusting said pilot pressure at a desired value; and control means for monitoring vehicular attitude change of said vehicular body for producing a control signal depending upon monitored magnitude of attitude change for suppressing the attitude change, said control means supplying said control signal to said actuator for operating the latter to adjust the position of said second valve means. - View Dependent Claims (16, 17, 18)
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Specification