A road surface state estimation device includes a tire-side device and a vehicle-body-side system. The tire-side device is disposed in a tire. The vehicle-body-side system is disposed in a vehicle body. The tire-side device outputs a detection signal corresponding to a magnitude of vibration of the tire, generates road surface data based on the detection signal, and performs data communication with the vehicle-body-side system. The vehicle-body-side system acquires information related to the road surface state, performs the data communication with the tire-side device, transmits vehicle-body-side information indicating that the change in the road surface state occurs to the tire-side device when determining that a change in the road surface state occurs based on the information related to the road surface state, and estimates the road surface state based on the road surface data received by the second transceiver.

A method for checking the tire pressure of a vehicle (1), which vehicle comprises at least one vehicle wheel (3) and a vehicle body (2) which is supported elastically on the vehicle wheel (3). The wheel includes a tire (7), filled with gas, on which wheel the vehicle stands on a subsurface (8). The vehicle body (2) is loaded with an additional mass and thereby the vehicle body is stimulated into a mechanical oscillation (16) relative to the subsurface (8). A response signal (A), that characterizes the mechanical oscillation (16), is measured and analyzed, whereby at least one response value that characterizes the current gas pressure in the tire is determined.

A method for ascertaining the instantaneous roadway roughness in a vehicle. In the method, the frequency-dependent amplitude response is determined from the wheel speed, and a roughness characteristic variable is ascertained as a measure of the roadway roughness.

A method for efficiently estimating a degree of wear of a tire in which a normalized deformation speed index is set as a wear measure. The normalized deformation speed index is obtained by normalizing an index of a deformation speed near an edge of a tire contact patch, the index being calculated from magnitudes of peaks appearing in a radial acceleration waveform obtained by differentiating tire radial acceleration detected by an acceleration sensor. The degree of wear of the tire is estimated using the wear measure, the ground contact time ratio, a worn tire approximate formula and an approximate formula when a tire is new, which have been obtained in advance and each represents a relationship between the wear measure and the ground contact time ratio obtained by running a plurality of tires having tire sizes different from each other.

A tire device includes a vibration power generating element, a signal processing unit, and a transmitter. The vibration power generating element is arranged inside a tire and outputs a voltage corresponding to a time variation of a vibration generated in a tread of the tire. The signal processing unit is disposed inside the tire and performs signal processing on the voltage outputted from the vibration power generating element. The transmitter is arranged inside the tire and sends data subjected to the signal processing in the signal processing unit to a device provided outside the tire. The signal processing unit and the transmitter are driven by power generated in the vibration power generating element.

A tire monitoring apparatus comprising a monitor installed on a tire and a pulse width measuring apparatus for measuring the width of pulses produced by the monitor. The pulse width measuring apparatus comprises a frequency analyzer for producing a frequency representation of the pulse, a signal processor for determining a minimum value of the frequency representation, and a pulse width estimator that inverts the minimum value to produce a measurement for the pulse width. The tire monitoring apparatus uses the pulse width measurement as an indication of characteristics of the tire.

A device for determining a rotational speed and a vibration of a wheel end of a vehicle, in particular a truck, is disclosed. The device includes a single sensor measuring a signal during a rotation of the wheel end. The sensor is arranged at the wheel end, and a determination unit for determining the rotational speed and the vibration of the wheel end using the signal of the single sensor is provided.

An embodiment system for monitoring a tire pressure includes a wheel speed sensor mounted on each wheel of a vehicle, a set button for resetting a pressure setting, and a controller configured to determine whether the tire pressure is low using the wheel speed sensor, output a low pressure warning, determine whether a user has an intention to reset the pressure setting when a manipulation of the set button is sensed after the low pressure warning is output, and reset the pressure setting in response to a response of the user.

A method for checking the tire pressure of a vehicle (1), which vehicle comprises at least one vehicle wheel (3) and a vehicle body (2) which is supported elastically on the vehicle wheel (3). The wheel includes a tire (7), filled with gas, on which wheel the vehicle stands on a subsurface (8). The vehicle body (2) is loaded with an additional mass and thereby the vehicle body is stimulated into a mechanical oscillation (16) relative to the subsurface (8). A response signal (A), that characterizes the mechanical oscillation (16), is measured and analyzed, whereby at least one response value that characterizes the current gas pressure in the tire is determined.

A method for checking and/or monitoring the use of a tire (1) mounted on a vehicle (7), comprises the following steps: acquisition, by a microphone (10) arranged inside the tire, of an acoustic response of said tire (1) obtained under the effect of a pulsed mechanical stress thereon, and processing of said response in the frequency domain, characterized in that said processing identifies, in the response in the frequency domain, two spectrum spikes situated on either side of a reference frequency corresponding to the first cavity mode of the tire and, as a function of the frequency deviation between the two duly identified spikes, determines information relating to at least one parameter of use of the tire.