Yasuki Motozawa

Car speaker system

A car speaker system which can be used to radiate sound either inside the vehicle in normal driving use or outside the vehicle when the vehicle is parked. A plurality of speaker units are mounted in a closed cabinet and the cabinet is swingably mounted along one side thereof in a casing. In a first swinging position of the cabinet, the speaker mounting surface of the cabinet is flush with the ceiling panel and the speakers radiate sound downwards into the passenger compartment of the vehicle, while in a second swinging position of the cabinet, the speaker mounting surface is perpendicular to the ceiling panel and the speakers face rearwards to radiate sound to the exterior through an open hatchback door.

A NEW CONCEPT FOR OCCUPANT DECELERATION CONTROL IN A CRASH

In order to minimize occupant injury in a vehicle crash, an approach was attempted to address this issue by making the wave form of vehicle body deceleration optimal to lower the maximum deceleration value applied to the occupant. A study with a one-dimensional two-mass model was conducted to the kinetic mechanism between the body deceleration wave form and the responding occupants motion while finding a mathematical solution for the optimal body deceleration wave form. A common feature of the three derived mathematical solutions is that they consist of three aspects: high deceleration, low or negative deceleration, and constant deceleration. This was demonstrated by simulation with a three-dimensional dummy. The results show that the response of the dummy closely agrees with that of the one-dimensional two-mass model, thus proving the adequacy of the mathematical solution, and that occupant injury was reduced. A type of new body construction is proposed to yield the optimal body deceleration wave form obtained from this research. (A) For the covering abstract see ITRD E106656.

Effects of seat belts worn by pregnant drivers during low-impact collisions

OBJECTIVE The aim of this study was to understand the injury mechanisms of pregnant drivers and associated fetal outcomes. STUDY DESIGN Frontal and rear impact tests using a dummy representing the anthropometry of a pregnant woman were conducted. RESULTS In frontal impact tests without a seat belt, abdominal pressure peaked at the point where the dummy contacted the steering wheel. Rear impact tests without a seat belt showed that the dummy moved forward because of rebound and contacted the steering wheel, which was avoided when a seat belt was worn. CONCLUSION Wearing a seat belt reduces abdominal pressure or prevents contact with the steering wheel during collisions.

A New Concept for Occupant Deceleration Control in a Crash - Part 2

In order to minimize occupant injury in a vehicle crash, an approach was attempted to address this issue by making the wave form of vehicle body deceleration optimal to lower the maximum value of the occupant deceleration. Prior study shows that the mathematical solutions for the optimal vehicle deceleration wave form feature consisting of three aspects: high deceleration, negative deceleration, and constant deceleration. A kinematical model which has separated mass of the vehicle was devised to generate an optimal vehicle deceleration wave form which consists of three segments including a segment of negative deceleration in the middle. The validity of this model has been certified by a mathematical study by using a one-dimensional lumped mass model. The effectiveness of the optimal vehicle deceleration wave form generated by this method was validated by a simulation with a three-dimensional dummy. An apparatus based on the physical model which consists of two separated mass was devised to confirm the results obtained from the three-dimensional dummy simulation. An experiment was conducted by utilizing an actual dummy and this apparatus. The experimental results show that the response of an actual dummy closely agrees with that of the three-dimensional simulated dummy.

A NEW CONCEPT FOR OCCUPANT DECELERATION CONTROL DURING VEHICLE CRASHES - STUDY OF THE VEHICLE MASS SEPARATION MODEL

In order to minimize occupant injury in a vehicle collision, an approach was attempted to address this issue by optimizing the waveform of the vehicle body deceleration to reduce the maximum deceleration applied to the occupant. A previous study has shown that the mathematical solution to the optimal vehicle deceleration waveform comprised three stages: high deceleration, negative deceleration, and constant deceleration. A kinematic model with separated mass of the vehicle was devised to generate the optimal vehicle deceleration waveform comprising three stages including a one with negative deceleration in the middle. The validity of this model has been confirmed by a mathematical study on a one-dimensional lumped mass model. The optimal vehicle deceleration waveform generated by this method was then validated by a three-dimensional dummy simulation. Apparatus based on the kinematic model consisting of results obtained from the dummy simulation. An experiment was conducted by utilizing an actual dummy and this apparatus. The experimental results show that the response of the actual dummy closely agrees with that of the three-dimensional simulated dummy. A simple FE model representing a hollow sheet metal member was devised. The simulation results show the potential of applying the optimal vehicle deceleration waveform. (A) For the covering abstract see ITRD E121867.