LOWER STIFFENER FOR VEHICLE AND MANUFACTURING METHOD THEREOF
A lower stiffener for a vehicle is provided. The lower stiffener includes a core cover longitudinally installed at a lower portion of a bumper, and an inner core longitudinally installed inside the core cover, wherein density and strength of the inner core are larger than those of the core cover.
1 . A lower stiffener for a vehicle comprising:
a core cover longitudinally mounted along a lower portion of a bumper; and
an inner core longitudinally installed inside the core cover, wherein density and strength of the inner core are larger than those of the core cover.
2 . The lower stiffener according to claim 1 , further comprising a mount integrally provided on the core cover to connect the core cover to a vehicle frame.
3 . The lower stiffener according to claim 1 , wherein the core cover and the inner core are integrally formed with a plastic composite material.
4 . The lower stiffener according to claim 1 , wherein the inner core twists along the entire length thereof, and the core cover surrounds the inner core.
5 . The lower stiffener according to claim 2 , further comprising a reinforcing rib to connect the core cover and the mount.
6 . The lower stiffener according to claim 3 , wherein the plastic composite material is a continuous fiber reinforced thermoplastic plastic.
7 . The lower stiffener according to claim 5 , wherein the mount and the reinforcing rib are formed of a glass fiber reinforced composite material.
8 . A method of manufacturing a lower stiffener for a vehicle, comprising:
forming a twisted inner core using a first plastic composite material; and
integrally forming a core cover over the inner core by placing a second plastic composite material around the inner core, and pressurizing the second plastic composite material.
9 . The method according to claim 8 , wherein the inner core is formed by twisting a plurality of first-plastic bars each being made of the first plastic composite material.
10 . The method according to claim 8 , wherein the core cover is formed by stacking a plurality of second-plastic bars, each being made of the second plastic composite material, around the inner core and pressurizing the stacked second-plastic bars.
11 . The method according to claim 8 , further comprising preheating the first and second plastic bars to a predefined temperature prior to the formation of the inner core.
12 . The method according to claim 11 , wherein the first and second plastic bars are formed prior to the preheating stage by impregnating a plurality of stretched fiber strands with fused plastic resin and injection-molding the former material into bars using a molding machine.