Assembly drawing of cylinder and suspension sphere for vehicle Y (1966)

In this document

This technical drawing, dated 1966 p. 64, represents a cross-section of a hydropneumatic cylinder and suspension sphere assembly.

The central diagram: the cylinder

The central drawing shows a cylinder in longitudinal cross-section, with a conical end, a threaded central section, and nested elements, connected on the right to the sphere. A handwritten annotation designates the material: "AU4G cylinder" (aluminium alloy), with the specification "exterior" p. 64. A handwritten arrow points to a detail whose annotation remains uncertain ("fixed" or "just"), and the markers "A" and another letter label the drawing, with no explicit legend preserved.

The diagram on the right: the sphere

On the right is a cross-sectional view of the suspension sphere, with a double wall and an internal corrugated membrane, connected to the threaded end of the cylinder. Handwritten annotations appear there but remain illegible.

References and identification

The title block at the bottom of the page specifies:

Context

The term "vehicle Y" corresponds, in Citroën's study vocabulary, to a project code name; the mention "DS" written in red suggests a connection—or a comparison—to the production model. The hydropneumatic suspension, combining a cylinder with a sphere containing gas and liquid separated by a membrane, is the core principle developed by Paul Magès and deployed on the Citroën DS from 1955 onwards.

The AU4G alloy (aluminium-copper) was commonly used in the automotive and aeronautical industry of the time for parts requiring lightness and mechanical strength, which would explain its use for this cylinder—information however external to the document, which does not justify this choice.

Archivist's perspective

This drawing illustrates, several years after the start of DS production, the continuation of engineering work on the core organ of the hydropneumatic suspension: the cylinder-sphere assembly. The mention "vehicle Y" suggests that this is a study for a project distinct from the production DS, perhaps an evolution or a future model, while remaining related to the DS system p. 64.

The average legibility of the document, with several uncertain handwritten annotations, limits the fine interpretation of dimensions and technical details. It nevertheless fits into the documentary continuity of the "Hydraulic organs" file, where other parts relating to the components of the suspension and the DS hydraulic circuit can be found, such as the Schematic diagram of the DS 19 hydraulic circuit or the Drawing of the DS high-pressure pump no. E 401.8444, which document other organs of the same hydraulic system.