Concentric cam with check valves in the spool for a phaser

摘要

A camshaft assembly (40) for an internal combustion engine has a hollow outer shaft (2) with slots (2a) along its length and an inner shaft (4) with holes (4a) along its length. The holes (4a) on the inner shaft (a) are aligned with the slots (2a) on the outer shaft (2). A first set of cam lobes (6) are fixed to the outer shaft (2) and a second set of cam lobes (8) are placed on the slots (2a) of outer shaft (2) with a clearance fit. A means fixes the second set of cam lobes (8) to the inner shaft (4). The means fixing the second set of cam lobes (8) may be a hollow pin (22) which is hydroformed or a rivet insert (52) which is expanded by insertion, pulling, and removal of a threaded rod (54).