Drive shaft made of fiber reinforced composite material and method of manufacturing the same

A shaft having a longitudinal body section and a yoke section formed with at least one end of the body section, said yoke section having a hole with a longitudinal axis related orthogonally to the longitudinal axis of said body section, and said body section and said yoke section being integrally made of a fiber reinforced composite material including a filament and a plastic adhered to the filament, said shaft comprising:

• a plurality of shaft fiber layers forming said body section, each shaft fiber layer including a plurality of shaft fiber elements disposed at predetermined intervals, said shaft fiber elements being inclined with respect to said longitudinal axis of the body section;
• a plurality of yoke fiber layers forming the yoke section, each yoke fiber layer including a plurality of yoke fiber elements, each yoke fiber element having a first portion and a second portion, each portion having ends connected to associated shaft fiber elements;
• and
• wherein each yoke fiber element has at least one of a closed loop arrangement and an open loop arrangement, said closed loop arrangement being defined by said yoke fiber elements completely looping around the hole such that said first portion of each yoke fiber element crosses over said second portion of each yoke fiber element, and said open loop arrangement being defined by said yoke fiber elements incompletely looping around the hole such that said first portion of each fiber element does not cross over said second portion, said yoke fiber elements of said open loop arrangement being disposed symmetrically with respect to a plane containing both of said longitudinal axes.

A shaft having a body section and a yoke section, formed by using a mandrel including a mandrel body, a support pin penetrating the mandrel and a plurality of pins arranged on a periphery of the mandrel body near the support pin, and by arranging a filament with a resin in a layered form on the mandrel, said shaft being formed by:

• arranging an end of the filament along the mandrel body;
• changing a direction of the arrangement of the filament by engaging the filament with a predetermined one of the pins and partly forming a fiber layer of the yoke section in one of an open loop arrangement and a closed loop arrangement by looping the filament about the support pin;
• wherein in said closed loop arrangement, the filament is completely looped around the support pin such that a first portion of the filament crosses over a second portion of the filament, and wherein in said open loop arrangement, the filament incompletely loops around the hole such that a first portion of the filament does not cross over a second portion of the filament;
• partly forming a fiber layer of the body section by arranging the filament along the periphery of the body section after changing again the direction of the arrangement of the filament by engaging the filament with a different pin than the predetermined pin, such that said filament pivots about said pin forming a predetermined angle between a portion of the filament on the body portion proximate the pivot and a portion of the filament on the yoke section proximate the pivot;
• removing the pins;
• curing the resin;
• removing the support pins;
• and
• removing the mandrel.