US 4,907,680 A · Semi-active damper piston valve assembly

Abstract

An improved isolation system for time responsive attenuation control led electromechanical valve assembly comprising the piston of motion between spaced members is provided having a remotely actuator of a fluid damper for generating motion attenuating forces. The piston valve assembly employs a moving coil valve slider moveable between first and second positions to generate damper forces independently of the fluid pressure differential between opposing fluid chambers. Direct flow passages extend through the piston valve assembly between the opposing chambers. In the first position of the valve slider, fluid flow is substantially permitted through the direct flow passages to provide a substantially nonresistant damper force. In the second position, the valve slider intersects internal porting portions of the direct flow passages to substantially restrict fluid flow therethrough and provide a resistant damper force. The valving element of the slider and the internal porting portions of the direct flow passages are relatively configured so that fluid flow through the direct flow passages meets the valve element at right angles to the direction of the slider motion. In the second position, fluid flow is restricted along either the inner or outer diameter surfaces of the valve element perpendicular to the axis of motion of the slider to prevent biasing even under extreme fluid pressure conditions. The direct flow passages are radially spaced to provide radially equalized pressure forces on the slider to prevent jamming. In an alternative embodiment, the piston valve assembly includes a unidirectional flow arrangement across the valve element during both extension and retraction of the fluid damper. The arrangement of flow passages and check valves requires fluid flow across the slider radially outwardly at all times.

Drawings

Drawings are temporarily unavailable. Open the PDF at USPTO

Drawings

Claims5

Dependent claims

A damping system for attenuation of motion between spaced members providing a controllable damper force operative independently of the motion condition of the damper, having a cylinder containing a damping fluid, and a piston slideably disposed within the cylinder in response to relative motion between the spaced members and dividing the cylinder into opposing fluid chambers, the improvement comprising:

flow passages through said piston having openings thereof in communication with each of said opposing chambers and having orthogonal portions thereof interiorly positioned within said piston for permitting regulated flow of fluid therethrough between said opposing chambers;
a slider within said piston having a moving coil portion and a valve element portion operably interconnected and axially reciprocative relative to a permanent magnetic field within said piston between a first position and a second position dependent upon the direction of electric current passing through said moving coil;
wherein in said first position flow of fluid between said opposing chambers is substantially unrestricted through said flow passages and in said second position said valve element intersects said orthogonal portions of said flow passages to substantially restrict flow of fluid therethrough, said slider being axially reciprocative between said first and second positions independently of the fluid pressure differential between said opposing chambers;
said flow passages including unidirectional flow means for flow of fluid radially outwardly from the central axis of said piston through said orthogonal portions and across said valve element during flow in both compression and extension of said piston.

1 more element

A damper assembly for providing a controllable damper force between spaced members operative independently of the motion condition of the damper, having a cylinder containing a damping fluid, and a movable piston slideably disposed within the cylinder in response to relative motion between said spaced members and dividing the cylinder into opposing first and second chambers, comprising;

control valve means located within said movable piston responsive to a command signal for regulating flow of fluid between said opposing chambers operative independently of the fluid pressure differential between said opposing first and second chambers;
said control valve means including a valve slider having a coil member thereof oriented in a permanent magnetic field, wherein said valve slider is rapidly movable within said piston in response to the direction of electric current through said coil member between a first position in which flow of fluid between said chambers is permitted and a second position in which flow of fluid is substantially restricted;
a valve element portion of said valve slider having an annular top surface and inner and outer diameter surfaces;
radially spaced direct flow passages through said piston interconnecting said opposing chambers for flow of fluid therebetween, said direct flow passages including an annular valve receiving channel such that in said first position, fluid flows over said annular top surface of said valve element and through said annular valve receiving channel, and in said second position, said valve element obstructs said annular valve receiving channel to substantially restrict flow of fluid between said opposing chambers;
said annular valve receiving channel including an elevated valve guide means within said piston for receiving said annular top surface of said valve element, wherein restriction of fluid flow occurs along one of said inner and outer diameter surfaces, thereby substantially minimizing biasing of said valve element along its direction of reciprocative motion.

2 more elements

Dependencies are inferred from the claim text.

Description7,674 words

Summary2,026 words

#The present invention relates generally to semi-active damping assemblies and more particularly provides a uniquely configured semi-active damper incorporating a remotely controlled electromechanical valve within a piston. Specifically, the valve is of the voice coil type for real time response to command signals for continuous control of resistant force generated by the damper.

#As exemplified in U.S. Pat. Nos. 3,807,678; 4,660,686; 4,468,050; and 4,468,739, a variety of hydraulic dampers of the semi-active type have been proposed for attenuating motion between relatively movable members, such as in vehicular suspension systems and for other applications. Development of semi-active devices has been a natural result of the inherent limitations found in passive systems and the expense and power requirements associated with purely active systems.

#As referred to herein, a passive motion attenuation system, such as a standard spring and shock absorber combination, exhibits performance which is solely a function of its inherent structural characteristics. The damping parameters chosen represent a design compromise over the full range of shock and vibration motion experienced by the system. Active systems, on the other hand, employ a damper force which can be made proportional to the absolute velocity or other quantity of the mass to be isolated resulting in an externally generated force in the damper which is independent of the relative movement of the damper. This may be accomplished through the use of a hydraulically pumped force-generating actuator. The result is controlled damping force at the expense of large auxiliary power requirements. Especially heavy vehicles are ill suited to provide appropriate power to drive such active systems, while the elaborate and costly components required for implementation even in standard vehicles also makes them a poor design choice. Further, the inertial characteristics of the hydraulic pumping means, fluid and servo valves within the active system are not satisfactorily responsive at high frequencies due to the inability of such equipment to rapidly respond to control signals.

Brief description of the drawings12 figures

#For a better understanding of the invention, reference may be made to the following description of exemplary embodiments, taken in conjunction with the figures of the accompanying drawings, in which:

#FIG. 1 is a schematic representation of an isolation system according to the present invention showing a controllable valve within the piston of a fluid damper;

#FIG. 2 is a partial cross-sectional view of a fluid damper illustrated in FIG. 1 incorporating a fast-acting valve of the present invention within the piston;

Detailed description5,162 words

#Referring now to the Drawings, FIG. 1 illustrates a schematic representation of an isolation system 10 of the present invention. The isolation system 10 resiliently supports mass 12 relative to a support 14 utilizing in parallel a passive isolator 16 and a fluid damper 18. Fluid damper 18 is of the semi-active type and is externally controllable independently of the motion condition of the system by signal control means 20. In accordance with damper performance requirements typically associated with semi-active devices, a piston valve assembly 22 regulates fluid flow within damper 18 to adjust the damping characteristics of the system. In this manner, controllable counteracting forces are generated which reduce the transmissibility of the shock or vibratory condition being encountered between mass 12 and support 14; particularly in the amplification range of passive isolator 16. Piston valve assembly 22 is uniquely constructed to comprise the piston of a standard configured shock aborber for ready adaptablity to conventional automobile, truck, military and other vehicle suspension systems. The concepts herein also may well be employed in additional nonconventional vibration isolation applications.

#As discussed, know variable dampers are limited in their performance, reliability and commercial production compatibility. In addition, less sophisticated, adjustable shock absorbing systems which incorporate an electromechanical valve within the piston are not designed for application to fast-acting valve arrangements such as those required for real-time response in semi-active systems.

#Attempts to overcome these problems either by complex mechanical structures or by adaptation of existing valve technology to desirable fast-acting systems have not been entirely satisfactory.

Semi-active damper piston valve assembly

Life of this patent

Semi-active damper piston valve assembly

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims5

Description7,674 words

Drawings

Classification2 codes

Life of this patent

Description7,674 words