Abstract: A wear-condition-sensing device includes an element configured to generate voltage based on deformation of a tread portion during tire rotation, a voltage detection unit configured to detect the voltage generated by the element, a storage area configured to store waveform data over time of the voltage detected by the voltage detection unit, a calculation unit configured to calculate an index value of voltage change based on the waveform data stored in the storage area, and a determination unit configured to determine a progress condition of wear of the tread portion by comparing the index value calculated by the calculation unit with reference information.

Abstract: A wear state detection device includes an element configured to generate voltage based on deformation of a tread portion during tire rotation, a voltage detection unit configured to detect the voltage generated by the element, a speed detection unit configured to detect vehicle speed or tire rotation speed, a storage area configured to store waveform data over time of the voltage detected by the voltage detection unit together with the vehicle speed or the tire rotation speed detected by the speed detection unit, a calculation unit configured to calculate frequency of exceedance of a predetermined threshold value based on the waveform data in a predetermined speed range and a predetermined time period stored in the storage area, and a determination unit configured to determine a progress condition of wear of the tread portion based on the frequency of exceedance of the predetermined threshold value calculated by the calculation unit.

Abstract: A composite piezoelectric element includes a first electrode layer, a piezoelectric substance layer disposed on the first electrode layer, and a second electrode layer disposed on the piezoelectric substance layer, and, in plan view, a measuring unit including the first electrode layer, the piezoelectric substance layer, and the second electrode layer and a buffer portion in which the piezoelectric substance layer is not provided.

Abstract: A tire deterioration inferring (estimating) method uses a tire deterioration inferring device placed on the inner surface of a tire. The method has: a deformation velocity measurement step of measuring a tire deformation velocity, which is the deformation velocity of the tire while the tire is rotating, and obtaining time-series changes in the tire deformation velocity; a calculation step of calculating peak values of the tire deformation velocity from the time-series changes in the tire deformation velocity; and an inference step of inferring the degree of the deterioration of the tire by using a first peak value, which is a peak value of the tire deformation velocity before and at the stepping of the tire or at and after the kicking of the tire, the first peak value being in the time-series changes in the tire deformation velocity.

Abstract: A method creates determination spaces for determining a road surface state of a road surface on which a vehicle is running from output waveform data obtained by measuring changes in a physical quantity of a tire of the vehicle during the running using information regarding road surfaces and the output waveform data. The method includes obtaining the output waveform data in a plurality of different road surface states and a running condition at times of measurement of the output waveform data, classifying the output waveform data into a plurality of groups on a basis of the running condition, performing, for each group, machine learning using training data where the output waveform data is associated with information regarding the road surface states, and creating the determination space corresponding to the group.

Abstract: A tire position identification device is provided as a device that can identify the positions of wheels to which tires are attached by using information about other than air pressure. The tire position identification device has: deformation detection units, each of which can detect deformation of the relevant tire; a turn detection unit that can detect whether a vehicle having the tires and wheels has made a turn and can also detect the direction of the turn; a speed detection unit that can detect the speed of the vehicle, and a control unit that infers the positions of the wheels to which the tires are attached according to the deformation of the tires, the direction of the turn of the vehicle, and its speed.

Abstract: A tire information detection device that detects tire information including at least one of wear, deformation, road surface state, ground contact state, presence/absence of failure, travel history, load state, or frictional coefficient, includes at least one detection unit disposed on a tire inner surface, a power supply unit to supply power to the detection unit, a position information detection unit to detect position information of the tire or a vehicle, an additional information acquisition unit to acquire additional information associated with the position information, a determination unit to determine whether a current position specified based on the position information is included in an area that satisfies a determination condition extracted from the additional information, and a control unit to control measurement of the detection unit based on a determination result from the determination unit.

Abstract: Provided is a tire information detecting device capable of determining an attachment state of a sensor module based on a measurement value supplied from the sensor module installed in a pneumatic tire and accurately detecting tire information. A tire information detecting device (10) configured to detect tire information including at least one of wear of a tire, deformation of the tire, a road surface state, a ground contact state of the tire, presence of failure of the tire, a travel history of the tire, or a load state of the tire includes at least one sensor module (20) disposed on a tire inner surface and a determination unit (15) configured to determine an attachment state of the sensor module (20) based on a measurement value supplied from the sensor module (20).

Abstract: A tire wear measuring device that detects wear of a tire based on a magnetic field from a magnetic object embedded in the tire includes magnetic sensors and a battery. The battery is capable of transmitting the magnetic field from the magnetic object, and has an outer edge from which the magnetic field from the magnetic object is emitted as an emission magnetic field. Each of the magnetic sensors is disposed in a position where the emission magnetic field is detectable by the sensor.

Abstract: A wear-condition-sensing device includes an element configured to generate voltage based on deformation of a tread portion during tire rotation, a voltage detection unit configured to detect the voltage generated by the element, a storage area configured to store waveform data over time of the voltage detected by the voltage detection unit, a calculation unit configured to calculate an index value of voltage change based on the waveform data stored in the storage area, and a determination unit configured to determine a progress condition of wear of the tread portion by comparing the index value calculated by the calculation unit with reference information.

Abstract: A wear state detection device includes an element configured to generate voltage based on deformation of a tread portion during tire rotation, a voltage detection unit configured to detect the voltage generated by the element, a speed detection unit configured to detect vehicle speed or tire rotation speed, a storage area configured to store waveform data over time of the voltage detected by the voltage detection unit together with the vehicle speed or the tire rotation speed detected by the speed detection unit, a calculation unit configured to calculate frequency of exceedance of a predetermined threshold value based on the waveform data in a predetermined speed range and a predetermined time period stored in the storage area, and a determination unit configured to determine a progress condition of wear of the tread portion based on the frequency of exceedance of the predetermined threshold value calculated by the calculation unit.

Abstract: A tire deterioration inferring (estimating) method uses a tire deterioration inferring device placed on the inner surface of a tire. The method has: a deformation velocity measurement step of measuring a tire deformation velocity, which is the deformation velocity of the tire while the tire is rotating, and obtaining time-series changes in the tire deformation velocity; a calculation step of calculating peak values of the tire deformation velocity from the time-series changes in the tire deformation velocity; and an inference step of inferring the degree of the deterioration of the tire by using a first peak value, which is a peak value of the tire deformation velocity before and at the stepping of the tire or at and after the kicking of the tire, the first peak value being in the time-series changes in the tire deformation velocity.

Abstract: A composite piezoelectric element includes a first electrode layer, a piezoelectric substance layer disposed on the first electrode layer, and a second electrode layer disposed on the piezoelectric substance layer, and, in plan view, a measuring unit including the first electrode layer, the piezoelectric substance layer, and the second electrode layer and a buffer portion in which the piezoelectric substance layer is not provided.

Abstract: An electromagnetic fuel injection valve includes a valve housing coupled to at one end thereof to a valve seat member; a stationary core coupled to the other end of the valve housing; and a valve assembly comprised of a movable core slidably accommodated in the valve housing, and a valve member connected to the movable core through a rod portion and adapted to cooperate with the valve seat. In the electromagnetic fuel injection valve, the valve housing is provided with a guide portion on which the valve assembly is axially slidably carried, and a high-hardness coating of diamond-like carbon including silicon is formed on an outer peripheral surface of the valve assembly contacting with the guide portion. The surface roughness Rmax of the high-hardness coating is set in a range of 0.05 to 0.2 ?m.

Abstract: An electromagnetic fuel injection valve includes a valve housing coupled to at one end thereof to a valve seat member; a stationary core coupled to the other end of the valve housing; and a valve assembly comprised of a movable core slidably accommodated in the valve housing, and a valve member connected to the movable core through a rod portion and adapted to cooperate with the valve seat. In the electromagnetic fuel injection valve, the valve housing is provided with a guide portion on which the valve assembly is axially slidably carried, and a high-hardness coating of diamond-like carbon including silicon is formed on an outer peripheral surface of the valve assembly contacting with the guide portion. The surface roughness Rmax of the high-hardness coating is set in a range of 0.05 to 0.2 &mgr;m.