Vehicle impact absorbing member
Provided is a shock absorber for a vehicle, which, when it is crushed, can break and open a part of the wall thereof earlier than the time of the break of an explosion inducing section, to thereby exclude the effect of the air being present inside a hollow portion and exhibit stable shock-absorbing capability and also maintain a satisfactory shock-absorbing capability over a wide range of temperature from a high temperature to a low temperature independently of the temperature of the open air. A shock absorber ( 1 ) is a hollow structure integrally molded through blow molding. The shock absorber ( 1 ) has at least one explosion inducing section ( 12 ). The explosion inducing section ( 12 ) comprises a protruded ridge ( 13 ) in a notch form formed on the surface of the wall of the shock absorber ( 1 ). The shock absorber ( 1 ) comprises a thermoplastic polymer alloy of a polyolefin type resin and an amorphous resin.
1. A vehicle impact absorbing member formed from a thermoplastic resin by blow molding comprising:
opposing first and second walls partially defining a hollow portion;
a plurality of first recessed columns integrally molded from said first wall;
a plurality of second recessed columns integrally molded from said second wall;
weld surface being welded leading end surfaces of the first and second recessed columns; and
at least one breaking induction section formed on at least one of said first recessed columns.
2. A vehicle impact absorbing member according to claim 1 , wherein the breaking induction section is a relatively thinned thin-wall portion of a wall of at least one said first recessed column.
3. A vehicle impact absorbing member according to claim 1 wherein the breaking induction section is a notch-shaped protrusion or groove formed on a wall of at least one of said first recessed column.
4. A vehicle impact absorbing member according to claim 1 , wherein the breaking induction section is a flectional portion of a wall of at least one of said first recessed column.
5. A vehicle impact absorbing member according to claim 1 , further comprising an additional breaking induction section is formed in a wall of either said first recessed column or said second recessed column.
6. A vehicle impact absorbing member according to claim 1 , wherein the impact absorbing member is formed from a thermoplastic resin having a bend elastic modulus of 10000 kg/cm 2 or above and an Izod impact value of 35 kg/cm 2 or less at an ambient temperature.
7. A vehicle impact absorbing member according to claim 1 , wherein the impact absorbing member is formed from a thermoplastic resin that is a polymer alloy of a polyolefin resin and an amorphous resin.
8. A vehicle impact absorbing member according to claim 7 , wherein the polyolefin resin is a polypropylene resin, and the amorphous resin comprises at least one resin selected from the group consisting of a polypropylene resin, an ABS resin, and a modified PPE resin and a mixture thereof.