US 3,941,403 AGranted

Hydro-pneumatic suspension unit

AssigneeNissan Motor Co., Ltd.

InventorMituo Hiruma

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Abstract

Herein disclosed is a hydro-pneumatic self-levelling suspension unit for an automotive vehicle, serving not only as a shock-absorber responsive to jounces and rebounds of a vehicle body and a self-levelling mechanism capable of automatically adjusting the height of the vehicle body responsive to change in the load applied to the vehicle body but as a level selector mechanism which is manually operated to stepwise vary the height of the vehicle body. The level selector mechanism comprises means stepwise extensible in an axial direction of the suspension unit between a fully contracted position and a fully extended position and biased toward the fully contracted position. The extensible means is stepwise extended to one or more lengths between the fully contracted and extended positions by selective application of fluid pressure thereon.

Claims7

Dependent claims

A hydro-pneumatic self-levelling suspension unit for an automotive vehicle comprising first and second cylindrical members which are telescopically connected together and which are axially movable relative to each other, self-levelling valve means disposed in said first cylindrical member and having a first position operative to direct fluid pressure into the first and second cylindrical members for causing the first and second cylindrical members to axially move relative to each other in directions to axially extend the suspension unit and a second position operative to discharge the fluid pressure from the first and second cylindrical members for causing the first and second cylindrical members to axially move relative to each other in directions to axially contract the suspension unit, resilient biasing means disposed in the first cylindrical member and engaging said valve means for biasing the valve means toward an equilibrium position between said first and second positions of the valve means thereby holding the suspension unit in a balanced condition, hydro-pneumatic spring means operative to compensate for fluctuations in the fluid pressure in said first cylindrical member, valve actuating means disposed in said second cylindrical member and engaging said resilient biasing means, said valve actuating means being stepwise extensible in an axial direction of said cylindrical member between a fully contracted length and a fully extended length for actuating said valve means through said resilient biasing means into said first position responsive to extension of said valve actuating means and into said second position responsive to contraction of the valve actuating means, said valve actuating means being biased toward said fully contracted length partly by said resilient biasing means and partly by the fluid pressure in the first and second cylindrical members, fluid supply means having a plurality of operative positions for supply working fluid to the valve actuating means and causing the valve actuating means to be selectively stepwise extended or contracted between said fully contracted length and said fully extended length, and manually-operated control means for manually actuating the fluid supply means selectively into any of said operative positions thereof.

A hydro-pneumatic self-levelling suspension unit, in which said valve actuating means comprise a plurality of plungers which are axially arrayed substantially in line with each other in the second cylindrical member and which are engageable end-to-end with each other, each of the plungers being axially movable between a first extreme position remotest from said self-levelling valve means and a second extreme position closest to the valve means, the plunger located closest to the valve means being connected to said resilient biasing means, said fully contracted length of the valve actuating means being achieved with all of the plungers held in the respective first extreme positions thereof and said fully extended length of said valve actuating means being achieved with the plunger remotest from said valve means held in the first extreme position thereof and the plunger closest to the valve means held in the second extreme position thereof, the plunger closest to the valve means being stepwise moved between the first and second extreme positions thereof by the fluid pressure developed in the valve actuating means by the working fluid directed to the actuating means from said fluid supply means, the working fluid from the fluid supply means being applied to at least one of the plungers which is selected depending upon the operative position selected in the fluid supply means.

Dependencies are inferred from the claim text.