Takehiro Co., Ltd.

Toyota Boshoku Corporation

Toyota Boshoku Kabushiki Kaisha

Hideyuki Mori

Sohei Matsuyama

Masaki Ishikawa

Youhei Ishikawa

Toru Inoue

A sound insulator of the invention includes a sound absorption layer and an air-impermeable resonance layer, which are bonded to each other via an adhesive layer. The sound absorption layer has a thickness in a range of 5 to 50 mm, an area-weight of not greater than 2000 g/mand a two-layer structure of a high-density sound absorption layer and a low-density sound absorption layer. The high-density sound absorption layer is bonded to the air-impermeable resonance layer via the adhesive layer and has a density in a range of 0.05 to 0.20 g/cmand a thickness in a range of 2 to 30 mm. The low-density sound absorption layer is bonded to the other face of the high-density sound absorption layer via an adhesive layer and has a density in a range of 0.01 to 0.10 g/cmand a thickness in a range of 2 to 30 mm.

Ultra-light sound insulator

A sound insulator of the invention includes a sound absorption layer and an air-impermeable resonance layer, which are bonded to each other via an adhesive layer. The sound absorption layer has a thickness in a range of 5 to 50 mm, an area-weight of not greater than 2000 g/mand a two-layer structure of a high-density sound absorption layer and a low-density sound absorption layer The high-density sound absorption layer is bonded to the air-impermeable resonance layer via the adhesive layer and has a density in a range of 0.05 to 0.20 g/cmand a thickness in a range of 2 to 30 mm. The low-density sound absorption layer is bonded to the other face of the high-density sound absorption layer via an adhesive layer and has a density in a range of 0.01 to 0.10 g/cmand a thickness in a range of 2 to 30 mm.

The objective of the present invention is to efficiently and inexpensively mass-produce a sound insulator for a vehicle which is light in weight and has excellent sound insulating properties. For this purpose, the ultra-light sound insulator of the present invention is composed of a felt single sheethaving a vehicle interior side surfaceand a vehicle exterior side surfaceand being thermoformed of cotton fibers and binder fibers which are tangled and contacted and jointed to each other in a random manner. The ratio of the stiffness of the vehicle interior side surfaceto that of the vehicle exterior side surfaceis set to be in a range of 1.1 to 10. The single sheetalso has an area of gradually-decreasing stiffnessthat spreads over at least one part of the area between the vehicle interior side surfaceand the vehicle exterior side surface. The area of gradually-decreasing stiffnesshas a stiffness distribution pattern in which the stiffness decreases gradually from the vehicle interior side surfacetoward the vehicle exterior side surfacewith respect to the direction perpendicular to the vehicle exterior side surface

A sound insulator of the invention includes a sound absorption layerand an air-impermeable resonance layer, which are bonded to each other via an adhesive layer. The sound absorption layerhas a thickness in a range of 5 to 50 mm and an area-weight of not greater than 2000 g/m. The sound absorption layerhas a two-layer structure of a high-density sound absorption layerand a low-density sound absorption layer, which have different densities. The high-density sound absorption layeris bonded to the air-impermeable resonance layervia the adhesive layerand has a density in a range of 0.05 to 0.20 g/cmand a thickness in a range of 2 to 30 mm. The low-density sound absorption layeris bonded to the other face of the high-density sound absorption layer, which is opposite to the air-impermeable resonance layer, via an adhesive layerand has a density in a range of 0.01 to 0.10 g/cmand a thickness in a range of 2 to 30 mm. The structure of this sound insulator effectively reduces a noise level in a voice-tone frequency band, especially in a high frequency domain, thereby efficiently enhancing the clarity of conversion in a vehicle interior.

Growing community of inventors

Inuyama, Japan

Hideyuki Mori