Tire cavity noise has long been one of the main road noise issues. Various ideas for devices to reduce tire cavity noise have been patented or discussed in technical reports, but many issues remain for commercialization, and at present only some tires have appeared as products.
Therefore, technology was developed for mounting Helmholtz resonators on the wheels, enabling reduction of tire cavity noise without placing restrictions on the tires. The advantage of this technology is that the cost and productivity targets needed for mass production can be satisfied without impairing the tire and wheel functions.
The aim of this development was to construct low-cost device technology that is well-suited to mass production and enables reduction of tire cavity noise to an inaudible sound pressure without adversely affecting dynamic product marketability such as strength and durability performance and handling performance.
In order to realize that aim, the device configuration employed a structure that assembles separate thin, lightweight plastic resonators in the wheel well. The main structural feature is the fitting and fixing of thin, lightweight plastic Helmholtz resonators in grooves newly cut in the wheels, with the basic concept of the design being to increase the resonator holding force when centrifugal force acts upon it.
The cabin noise was verified by driving a vehicle equipped with these tire cavity noise-reducing wheels over a rough road surface. The results confirmed noise reduction effects of approximately −10 dB, and tire cavity noise was also reduced to an inaudible level.