Patent ID: 8365782

Claim:
A tire noise reduction device comprising: two main sound absorbing members for changing a cross-sectional area of a cavity of a tire in a circumferential direction of the tire, the two main sound absorbing members being disposed on an inner surface of a tread portion facing the cavity of the tire at two opposed locations in the circumferential direction of the tire, the two main sound absorbing members being formed of a porous material; and two assistant sound absorbing members disposed on the inner surface of the tread portion at two opposed locations in the circumferential direction of the tire between the two main sound absorbing members, the two assistant sound absorbing members being formed of a porous material, wherein the main sound absorbing members each comprise a first sound absorbing part located on a tread portion inner surface side thereof and a second sound absorbing part located on a side thereof away from the inner surface of the tread portion, the second sound absorbing part having a density lower than that of the first sound absorbing part, wherein the assistant sound absorbing members each have a density higher than that of the second sound absorbing part and equal to that of the first sound absorbing part, wherein each of the assistant sound absorbing members has a thickness less than that of the main sound absorbing members, and wherein the thickness of the assistant sound absorbing member is greater than the thickness of the first sound absorbing part.