US 6,662,913 B2 · Shock absorber

Abstract

A motor vehicle shock absorber (12) that has an additional or further spring biased fluid control valve (96) that disposed between the blow-off valve (46) and the compression chamber (34) of the shock absorber (12) and that provides enhanced damping performance characteristics during relatively low velocity movements of the piston assembly (24) in the recoil stroke direction, that is, at velocities lower than those which cause the blow-off valve (46) of the shock absorber (12) to open. The further spring biased fluid control valve (96) affords the shock absorber (12) a firmness vis-a-vis roll stability to the vehicle steering yet provides the consumer a desired “boulevard” or soft cushioned ride.

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Claims14

Dependent claims

In a shock absorber adapted for connection between the body of a motor vehicle and the suspension of the motor vehicle and for damping vibrations transmitted from the suspension to the body while the vehicle is being driven, the shock absorber including:

an inner tube having a first fluid filled cylindrical inner cavity therein, that has a compression end and an extension end, and that has a longitudinal central axis extending between the compression end and the extension end, a piston assembly that has a longitudinal central axis which is co-axial with the longitudinal central axis of the inner tube, that is disposed within the first cavity, that has a second internal chamber, that has a third chamber, that is reciprocally moveable within the inner cavity, parallel with the longitudinal central axis of the inner tube, selectively in a recoil stroke direction, where the piston assembly moves toward the extension end, and in a compression stroke direction, where the piston assembly moves toward the compression end, and that serves to divide the inner cavity into a compression working chamber, which is adjacent to the compression end of the inner tube, and an extension working chamber, which is adjacent to the extension end of the inner tube;
at least one restrictor opening that permits restrictive flow of fluid between the extension chamber and the second chamber of the piston assembly during movement of the piston assembly in the recoil stroke direction;
at least one orifice that is in the piston assembly and that permits a first predetermined volume of fluid to flow between the second chamber and the third chamber during relatively low velocity movement of the piston assembly in the recoil stroke direction;
a blow-off valve assembly that is disposed in the piston assembly between the second chamber and the third chamber, that when opened, permits a relatively large volume of fluid, as compared to the first predetermined volume of fluid flow, to flow from the second chamber to the third chamber, and that is normally biased closed with a first predetermined biasing force which is overcome so as to permit the blow-off valve to open when the piston assembly moves in the recoil stroke direction at a velocity in excess of a first predetermined velocity;
and a piston rod that has a longitudinal central axis, which is co-axial with the longitudinal central axis of the inner tube, that has an inner end, which is connected with the piston assembly, and that has an outer end, which extends out of the extension end of the inner tube;
the improvement comprising:
a second valve that is disposed in the piston assembly between the blow-off valve assembly and the compression chamber, that when open, permits a relatively large volume of fluid, as compared to the first predetermined volume of fluid, to flow from the third chamber to the compression chamber, and that is normally biased to a closed position with a second predetermined biasing force, which is less than the first predetermined biasing force and which is overcome so as to permit the second valve to open when the piston assembly moves in the recoil stroke direction at a second predetermined velocity that is less than the first predetermined velocity, so that the second valve in the piston assembly provides an initial firmness to the shock absorber damping before the blow-off valve opens and affords the shock absorber a firmness in regard to the roll stability to the vehicle steering yet providing a relatively soft cushioned or boulevard ride for the vehicle.

4 more elements

Dependencies are inferred from the claim text.

Description4,319 words

Summary1,723 words

#The present invention relates to hydraulic shock absorbers. More particularly, the present invention relates to an improved hydraulic shock absorber that is adapted for use with motor vehicle suspension systems and that includes additional valving that enhances the dampening characteristics of the shock absorber during low velocity movement of the piston assembly in the recoil or rebound stroke or motion direction.

#Hydraulic shock absorbers have long been commonly used in motor vehicle suspension systems to absorb unwanted road caused vibrations that normally occur while the vehicle is being driven. Specifically, shock absorbers are generally connected between the body (the sprung mass) and the suspension (the unsprung mass) of the motor vehicle to dampen vibrations transmitted from the suspension to the body.

#Hydraulic shock absorbers usually include a cylindrical tube (frequently known as the inner tube), that defines a cylindrical inner cavity. A piston assembly is slidably disposed in and is reciprocally movable within the inner cavity and serves to divide the inner cavity into two working chambers: a compression chamber; and a rebound chamber, both of which are filled with hydraulic fluid. A fluid reservoir communicates, through valving, with the working chambers, and is usually annularly defined between the inner tube and an outer tube which is concentrically mounted about the inner tube.

Brief description of the drawings3 figures

#In the drawings:

#FIG. 1 is a partial, vertical cross-sectional view of an improved shock absorber of the present invention, taken along its central longitudinal axis;

#FIG. 2 is a vertical cross-sectional view of the piston assembly of the present invention, taken along its central longitudinal axis, where the blow-off valve and second valve are shown in their closed positions; and

Detailed description2,436 words

#A shock absorber 12, which includes the present invention, is generally shown in FIG. 1. The shock absorber 12 is of conventional design and construction except as noted below with respect to the additional or second valving. More specifically, the shock absorber includes a cylindrical inner tube 14 that defines a cylindrical internal or inner cavity 16. An outer tube 18 is positioned concentrically about and radially outwardly from the inner tube 14 so that their central longitudinal axes are coaxial. The annular space between the tubes 14 and 16 defines a reservoir 22 for the hydraulic fluid or oil used with the shock absorber 12.

#A piston assembly 24, which will be described in more detail below, is disposed for reciprocal movement within the inner cavity 16. A piston rod 26 is connected at its lower or inner end 28 with the piston assembly 24 in a conventional manner. The outer or upper end 30 of the piston rod 26 extends without the inner cavity 14 in a conventional manner. The upper end 30 of the piston rod has a connector, not shown, which enables the shock absorber 12 to be connected with a vehicle body, not shown, in a conventional manner. The central longitudinal axes of the internal cavity 16, the tubes 14 and 18, piston assembly 24, and piston rod 26 are coaxial.

#The piston assembly 24 divides the internal cavity 16 into: an extension, or sometime called rebound chamber 32, which is adjacent the upper end of the internal cavity, as shown in FIG. 1; and a compression chamber 34, which is adjacent the lower end of the inner cavity 16, as shown in FIG. 1.

Shock absorber

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Shock absorber

Life of this patent

Life of this patent

Abstract

Drawings

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Claims14

Description4,319 words

Drawings

Classification2 codes

Life of this patent

Description4,319 words