Patent ID: 9242612
Filing Date: 2016-01-26
CPC Classification: B21D,B60R,F16F

Claim Text:
1. A shock absorbing member configured to absorb impact energy by being compressively deformed in an axial direction, comprising: an outer peripheral wall having a polygonal shape in cross-section perpendicular to the axial direction and including a plurality of side portions; and a plurality of ribs, on an inner side of the outer peripheral wall, radially extending from a central axis and connected to an intermediate position of each of the side portions, wherein a boundary position of adjacent side portions on an outer peripheral surface of the outer peripheral wall is defined as a vertex, an intermediate position of each side portion on the outer peripheral surface of the outer peripheral wall is defined as a rib connection point, and portions segmenting each of the side portion into two, with the rib connection point as a boundary, are each defined as a half-side portion, wherein, when being compressively deformed in the axial direction, the two adjacent half-side portions sandwiching the vertex buckling-deform repeatedly in the axial direction while being deformed convexly and concavely in different directions in a radial direction, with positions of the outer peripheral wall corresponding to the rib connection point and the vertex respectively as a node and an intermediate portion of each half-side portion as an anti-node, wherein the vertex of the outer peripheral wall and vicinity thereof are constituted as an arc-shaped vertex arc portion having a curvature radius, and wherein it is adjusted so as to satisfy a relation of 0<R/L≦1.15, where an intersection point of virtual extended lines of both outer peripheral surface linear portions of the two adjacent half-side portions sandwiching the vertex is defined as a virtual vertex, a length from the virtual vertex to the rib connection point close to the virtual vertex is defined as a half-side portion length, the side portion length is “L,” and a curvature radius of the outer peripheral surface of the vertex arc portion is “R”.