A tyre cavity noise absorber comprising a body 1 of sound absorbing material with an outer protective cover 3. The body of sound absorbing material is intended to be mounted to a wheel 2 of a wheel and tyre 6 assembly so that a surface of the body is exposed in a tyre cavity of the wheel and tyre assembly. The outer protective cover only partially covers said surface of the body of sound absorbing material such that the cover protects the body of sound absorbing material from a bead 7 of a tyre as a tyre is fitted to, or removed from, the wheel and the uncovered parts of the body of sound absorbing material are free to absorb sound.

A variable wheel resonator system for a vehicle can suppress a resonance noise in a wide resonance frequency band occurring during driving of the vehicle by variably controlling an amount of air flowing from a first air chamber of a tire to a second air chamber and then flowing again to the first air chamber through an on/off control of a solenoid valve mounted on a wheel resonator. The system can suppress the resonance noise in the resonance frequency band that differs in accordance with a road-surface input frequency change (road-surface impact change) input to the tire, a driving speed and turning condition change, and a temperature change of an internal air of the tire.

A wheel/hub assembly includes an axle shaft, a wheel, and a hub supporting the wheel on the axle shaft. The wheel/hub assembly has a target resonant frequency of vibration. A tuned mass-spring damper is vibrationally coupled to the wheel/hub assembly, and has a counteracting resonant frequency of vibration that is predetermined with reference to the target resonant frequency of vibration.

A device configured for coupling a resonator to a vehicle wheel, may include an annular first strap assembled with an external circumferential surface of the wheel rim and fixing positions of resonators disposed on the external circumferential surface of the wheel rim; and an annular second strap surrounding second flanges formed at second edge portions of the resonators based on an axial direction of the wheel rim and pressurizing the second flange toward the external circumferential surface of the wheel rim after first flanges, which are formed on second edge portions of the resonators based on an axial direction of the wheel rim, are inserted between the first strap and the external circumferential surface of the wheel rim.

Apparatus for applying noise reducing elements to tyres for vehicle wheels. The apparatus includes a loading station of stacks of noise reducing elements, an extraction station of noise reducing elements from each stack placed downstream of the loading station, and a conveyor placed downstream of the extraction station and extending along a predefined path. The conveyor is configured for supporting and advancing in a row the noise reducing elements extracted from the stacks which are then applied to a radially inner surface of the tyres. The extraction of each of the noise reducing elements contemplates: retaining a first noise reducing element placed at the base of a stack; raising the remaining noise reducing elements of the stack from the first noise reducing element; moving away the first noise reducing element according to a set path; and lowering the remaining noise reducing elements of the stack.

The invention relates to a pneumatic vehicle tire (L) having at least one acoustic element (8), wherein the tire (L), fitted on a wheel rim (16), encloses with the rim (16) a space inside the tire (17), wherein the acoustic element (8) comprising a body (12) and a layer (13) is arranged on an inner tire surface (10) involved in delimiting the space inside the tire (17), wherein the body (12) is arranged on the inner tire surface (10) and wherein the layer (13) is arranged on a surface region of the body (12) that is facing the space inside the tire (17). The object is to provide a tire which has improved acoustic properties with less use of porous noise-reducing material and the acoustic element of which is more resistant to pressure changes. This is achieved in that the layer (13) is arranged on at least 15% of that surface of the body (12) which faces toward the space inside the tire (17), in that the layer (13) has a first surface region (9) which is arranged at a distance from the inner tire surface (10), in that the first surface region (9) is connectable pneumatically to a surface region (11) lying opposite it and in that the layer (13) has a sound reflectance of at least 80% for a sound wave striking the first surface region (9). The invention also relates to a wheel rim (16) and to a wheel having such an acoustic element (8).

Apparatus for applying noise reducing elements to tyres for vehicle wheels. The apparatus includes a loading station of stacks of noise reducing elements, an extraction station of noise reducing elements from each stack placed downstream of the loading station, and a conveyor placed downstream of the extraction station and extending along a predefined path. The conveyor is configured for supporting and advancing in a row the noise reducing elements extracted from the stacks which are then applied to a radially inner surface of the tyres. The extraction of each of the noise reducing elements contemplates: retaining a first noise reducing element placed at the base of a stack; raising the remaining noise reducing elements of the stack from the first noise reducing element; moving away the first noise reducing element according to a set path; and lowering the remaining noise reducing elements of the stack.

A tire noise reduction apparatus may include a housing mounted on an external circumferential surface of a wheel rim on which a tire is mounted, the housing having an internal space and being open at one side in a circumferential direction of the wheel rim, wherein the housing includes a neck at an opposite side which is opposite to the open one side; and a movable member inserted into the internal space of the housing through the open one side of the housing and having an internal space in fluidical communication with the internal space of the housing, the movable member being mounted to the housing to be movable in a direction in which the movable member is inserted into the internal space of the housing and in a direction in which the movable member is withdrawn out of the housing.

A vehicle wheel includes a pair of vertical walls that extend vertically up from an outer circumferential surface of a well portion and extend in a wheel circumferential direction and a Helmholtz resonator that is disposed between the pair of vertical walls and bonded to side surfaces of the pair of vertical walls with an adhesive, in which the Helmholtz resonator is not bonded to the outer circumferential surface of the well portion.

A planar ratchet assembly is provided for a human-powered vehicle, and includes a first ratchet member and a second ratchet member. The first ratchet member includes an axial surface defining a plurality of first serrated teeth having a first driving surface and a first non-driving surface. At least one of the first non-driving surfaces includes a convex curved surface that has a radius of curvature of at least 0.5 mm. The second ratchet member includes an axial surface defining a plurality of second serrated teeth having a second driving surface and a second non-driving surface. The first ratchet member and the second ratchet member rotate together in a driving direction. At least one of the first ratchet member and the second ratchet member moves in an axial direction to permit relative rotation between the first ratchet member and the second ratchet member in a non-driving direction.