208 自動車懸架装置用コロイダルダンパーの最適設計に関する研究

抄録

Usual car suspensions employ oil dampers mounted in parallel with compression helical springs, the latter providing the necessary restoring force to bring back the suspension to its initial position after a complete cycle of compression-extension. The energy of shock and vibration is mainly stored by the spring during compression and then transferred to and dissipated by the oil damper during extension. On the other hand, in the case of a colloidal damper, since the liquid is forced to penetrate the nanopores of lyophobic silica during compression but naturally exudes on the liquid-repellent surfaces at decompression, the restoring force is intrinsically achieved, and the helical spring can be omitted. In other words, the colloidal damper occurs as a machine element with a dual function, of absorber and spring, this allowing a compact and light design of the car suspension. In this work three types of suspensions were considered and modeled as follows: oil damper mounted in parallel with helical compression spring (Kelvin-Voigt model, consisted of a dashpot and an elastic element connected in parallel), and colloidal dampers without (Maxwell model, consisted of a dashpot and an elastic element connected in series) and with (standard linear model, consisted of a Maxwell unit connected in parallel with an elastic element) attached helical compression springs. Firstly, the transmissibility from the rough road to the car's body for all these suspensions was determined. Then, the optimal damping was found to minimize the transmissibility, i.e., to maximize the car's comfort. Examples of simplified, compact and light design are illustrated for the frontal and rear car suspensions. Thus, a reduction of the external diameter of about 60 % and a mass reduction of about 30 % was achieved in the case of autovehicle suspension.