Abstract: A transmitter for a tire condition monitoring apparatus is located in a tire of a vehicle and transmits data indicating the tire condition using a carrier wave. The transmitter includes an oscillating circuit and a controller. The oscillating circuit generates a carrier wave frequency and has a predetermined characteristic carrier wave frequency. The controller corrects the generated carrier wave frequency in accordance with the difference between the characteristic carrier wave frequency and a predetermined reference carrier wave frequency.

Abstract: A tire monitoring apparatus includes transponders and a transmitter-receiver. Each transponder is provided in one of the tires of a vehicle, and the transmitter-receiver is mounted on the body frame of the vehicle. In response to a predetermined interrogating radio wave, each transponder detects a condition of the corresponding tire and wirelessly transmits data representing the detected condition of the tire. The transmitter-receiver transmits the interrogating radio wave and receives data wirelessly transmitted by each transponder. In a part of a period during which the corresponding tire rotates through one revolution, each transponder passes through a communication range. The transmitter-receiver changes the time interval at which the interrogating radio wave is transmitted such that the interrogating radio wave is transmitted while the transponder is in the communication zone. As a result, the conditions of the tires are always monitored in a reliable manner.

Abstract: A tire condition monitoring apparatus includes a transmitter located in a tire of a vehicle. A trigger device includes a transmission antenna, a reception antenna, and an antenna unit. The transmission antenna wirelessly transmits a trigger signal. The transmitter wirelessly transmits data indicating the tire condition in response to the trigger signal. The reception antenna receives the data wirelessly transmitted from the transmitter. The antenna unit incorporates the transmission antenna and the reception antenna. Therefore, the trigger device reliably receives data wirelessly transmitted from the transmitter.

Abstract: A transmitter is located in a tire of a vehicle and transmits data indicating a tire condition using a carrier wave. The transmitter has an oscillator circuit and a transmission controller. The oscillator circuit generates the carrier wave. The transmission controller compensates a deviation of the amplitude of the carrier wave generated by the oscillator circuit relative to a predetermined reference value such that the amplitude of the carrier becomes equal to the reference value. This is capable of maintaining a constant amplitude of a carrier wave.

Abstract: Each of transmitters includes a condition detecting device for detecting the condition of a corresponding tire, and an acceleration detecting device for detecting the direction of acceleration accompanying rotation of the corresponding tire. Each transmitter wirelessly transmits data containing data representing the condition of the tire and data representing the direction of the acceleration. A repeater receives data from the transmitters provided in front tires or data from the transmitters provided in rear tires. When receiving data from any of the transmitters, the repeater wirelessly transmits a response signal when a predetermined period has elapsed after the reception of the data. A receiver receives data from the transmitters and the response signal from the repeater.

Abstract: A transmitter in an apparatus for monitoring a condition of a tire of a vehicle includes a circuit portion and a casing that accommodates the circuit portion. The casing has a first pressure transmitting portion that transmits the pressure in the tire to the circuit portion so that the circuit portion can detect the pressure in the tire. The pressure transmitted to the circuit portion through the first pressure transmitting portion produces force that presses the circuit portion. The casing further has a second pressure transmitting portion that transmits the pressure in the tire to the circuit portion to apply force that acts against the pressing force to the circuit portion. Therefore, the transmitter prevents a substrate from flexing.

Abstract: A transmitter in an apparatus for monitoring a condition of a tire attached to a wheel of a vehicle is fixed to the wheel such that the transmitter faces an outer circumferential surface of a wheel rim. The transmitter includes a circuit portion that detects the condition of the tire. The transmitter includes a casing that accommodates the circuit portion, and a leg that extends from the casing toward the outer circumferential surface of the wheel rim. The extended amount of the leg is adjustable such that the leg contacts the outer circumferential surface of the wheel rim when the transmitter is fixed to the wheel. Therefore, the transmitter is mounted to the wheel such that legs of the casing abut against the wheel rim regardless of the size of the wheel.

Abstract: Different types of data included in a signal transmitted by a transmitter, except for synchronous data, are each configured by a binary code signal of a predetermined bit count. The synchronous data is configured by a signal of a pattern different from the bit codes that configure the data other than the synchronous data. This enables a receiver to recognize the synchronous data in the transmitted signal easily and reliably. Further, the data length of the synchronous data is shortened. This shortens the data length of the signal, thus ensuring optimal wireless communication between the transmitter and the receiver.

Abstract: A transmitter in an apparatus for monitoring a condition of a tire includes a pressure sensor, a transmission circuit, a valve stem, an MR sensor, and a magnetic ring. The valve stem has magnetic pieces. The pressure sensor measures the air pressure in the interior of the tire. The transmission circuit generates a transmission signal containing data that represents the measured air pressure. The magnetic ring magnetizes the magnetic pieces. The position of the magnetic ring relative to the magnetic pieces can be changed. A magnetized state of the magnetic pieces varies according to the position of the magnetic ring relative to the magnetic pieces. The MR sensor detects the magnetized state of the magnetic piece. The transmission signal contains data based on the detected magnetized state in addition to the tire condition data. This is capable of identifying the tire mount position.

Abstract: A transmitter has a tire condition sensor, a transmission circuit, a voltage sensor and an electricity control circuit. The tire condition sensor detects the condition of a tire. The voltage sensor detects a voltage of the battery. During a period from when the tire condition sensor detects the condition of the tire to when the transmission circuit starts transmitting the data, the electricity control circuit performs a transmission preparation process to gradually increase electricity supplied to the transmission circuit from a battery, thereby gradually increasing a radio wave output of the transmission circuit. If the value of the voltage detected by the voltage sensor is lowered to a lowest operation voltage of the transmitter during the transmission preparation process, the electricity control circuit limits the supply of electricity to the transmission circuit from the battery.

Abstract: A tire monitoring apparatus includes transponders and a transmitter-receiver. Each transponder is provided in one of the tires of a vehicle, and the transmitter-receiver is mounted on the body frame of the vehicle. In response to a predetermined interrogating radio wave, each transponder detects a condition of the corresponding tire and wirelessly transmits data representing the detected condition of the tire. The transmitter-receiver transmits the interrogating radio wave and receives data wirelessly transmitted by each transponder. In a part of a period during which the corresponding tire rotates through one revolution, each transponder passes through a communication range. The transmitter-receiver changes the time interval at which the interrogating radio wave is transmitted such that the interrogating radio wave is transmitted while the transponder is in the communication zone. As a result, the conditions of the tires are always monitored in a reliable manner.

Abstract: A tire status monitoring apparatus capable of providing notification of an abnormal status for a tire in accordance with the speed of a vehicle. The tire status monitoring apparatus includes transponders which are provided on the respective tires, detect statuses of the tires in response to a request signal and generate transponder data including data indicative of the statuses of the tires detected, and a transceiver which transmits the request signal to each transponder and receives the transponder data from each transponder. The transceiver determines the number of times the request signal is transmitted per unit time in accordance with the speed of the vehicle.

Abstract: A receiver of a tire status monitoring apparatus which can specify tire mounting positions and does not require initial registration work. The tire status monitoring apparatus includes a plurality of transmitters which are provided on the respective tires of a vehicle and transmit data indicating statuses of the respective tires. The data includes an identification code to identify each tire, and the receiver is supplied with an activation signal to activate a drive source of the vehicle. The receiver includes a reception unit which receives the data from the transmitters, and a control circuit which is connected to the reception unit and collates the identification code included in the data upon detection of the activation signal and specifies, based on the identification code, each transmitter which has transmitted the data.

Abstract: Each of transmitters includes a condition detecting device for detecting the condition of a corresponding tire, and an acceleration detecting device for detecting the direction of acceleration accompanying rotation of the corresponding tire. Each transmitter wirelessly transmits data containing data representing the condition of the tire and data representing the direction of the acceleration. A repeater receives data from the transmitters provided in front tires or data from the transmitters provided in rear tires. When receiving data from any of the transmitters, the repeater wirelessly transmits a response signal when a predetermined period has elapsed after the reception of the data. A receiver receives data from the transmitters and the response signal from the repeater.

Abstract: A transponder for a tire condition monitoring apparatus is provided. The transponder detects a condition of a tire and wirelessly transmits data representing the detected condition in response to radio waves having a field intensity equal to or greater than a predetermined level. The transponder is provided in a tire valve.

Abstract: A transmitter is provided in each of tires to wirelessly transmit data representing the condition of the associated tire and data representing the direction of acceleration. A first reception antenna receives data from the transmitters provided in left and right front tires. A second reception antenna receives data from the transmitters provided in left and right rear tires. When receiving data from one of the transmitters, the receiver determines the position of the tire in which the transmitter that is the source of the data is provided based on the levels of received signals each sent from the first reception antenna and the second reception antenna.

Abstract: A compact and light semiconductor sensor for detecting pressure and acceleration. A pressure sensor is formed on a first surface of an intermediate plate. An acceleration sensor is formed on a second surface of the intermediate plate. A first plate having a diaphragm is bonded to the intermediate plate to define a hermetic chamber of the pressure sensor. A second plate is bonded to the second surface of the intermediate plate. A spring support supports the mass in a manner relatively movable with respect to the second plate.

Abstract: A transmitter has a tire condition sensor, a transmission circuit, a voltage sensor and an electricity control circuit. The tire condition sensor detects the condition of a tire. The voltage sensor detects a voltage of the battery. During a period from when the tire condition sensor detects the condition of the tire to when the transmission circuit starts transmitting the data, the electricity control circuit performs a transmission preparation process to gradually increase electricity supplied to the transmission circuit from a battery, thereby gradually increasing a radio wave output of the transmission circuit. If the value of the voltage detected by the voltage sensor is lowered to a lowest operation voltage of the transmitter during the transmission preparation process, the electricity control circuit limits the supply of electricity to the transmission circuit from the battery.

Abstract: A transmitter device includes a rotational direction sensor that generates a specific pattern signal when a corresponding tire rotates. The pattern signal of the left tires is different from the pattern signal of the right tires. A front reception antenna is near the front tires. A rear reception antenna is near the rear tires. A receiver includes a switch circuit that selectively connects the front reception antenna or the rear reception antenna to a controller. When one transmitter device transmits a radio signal, the controller determines which transmitter device is the source of the radio signal in accordance with the level of the signals from the reception antennas and the pattern signal, which is included in the data transmitted by the transmitter device.

Abstract: A transmitter for a tire condition monitoring apparatus is located in a tire of a vehicle and transmits data indicating the tire condition using a carrier wave. The transmitter includes an oscillating circuit and a controller. The oscillating circuit generates a carrier wave frequency and has a predetermined characteristic carrier wave frequency. The controller corrects the generated carrier wave frequency in accordance with the difference between the characteristic carrier wave frequency and a predetermined reference carrier wave frequency.