2020 Volume 37 Pages 50-56
In order to reduce fatalities or serious injuries in traffic accidents, retaining a safer seated posture and proper occupant restraint is important, and the lack of them tend to cause serious abdominal injuries. The individual differences of the seated posture affects the occupant restraint by a seatbelt. This study aims to construct and commercialize technologies required for abdominal injury prevention based on the individual differences of the skeletal alignment in a seated posture and occupants' kinematics in a collision which was analyzed using human body models (HBMs). According to the analysis of individually different skeletal alignments in a seated posture, the seated postures are classified into two types: S-shape and kyphosis. For pelvis, the individual differences of ASIS shapes and the distances between ASIS and pubic symphysis were analyzed and incorporated into the HBMs to study occupants' kinematics. The analysis results of the kinematics indicated that the controlling the pelvic angle is essential to prevent the abdominal injuries.
Based on the results, three new technologies were applied to Mazda3: a new seat design to achieve the S-shaped posture, a seat-integrated lap belt anchor to reduce pelvic rotation, and the knee airbag to sustain the occupant in position while limiting the force into the abdomen. The safer seated posture structure together with the newly designed restraint systems further improve the occupant protection performance, bringing Mazda's "human-centered design" philosophy into shape.