Abstract: A tire pressure detecting device fixed to a wheel with a tire includes a pressure sensor detecting an internal pressure of the tire and transmits data of detection by the pressure sensor to a vehicle body by radio. The tire pressure detecting device further includes a compensation data storage storing compensation data for detection error specific to the pressure sensor and a compensation data transmitter obtaining the compensation data from the compensation data storage, transmitting the obtained compensation data to the vehicle body by radio.

Abstract: A transmitter for a tire condition monitoring apparatus includes a pressure sensor for detecting of the internal pressure of a tire, a transmission circuit for generating a transmission signal, and a transmission antenna for transmitting the transmission signal as a radio wave. The transmission antenna is a planar antenna and includes a plate-like transmission conductor for transmitting the radio wave. The transmission antenna is configured such that the radio wave transmitted from the transmission conductor becomes a circularly polarized wave. As a result, the transmitter has a superior transmission performance and a reduced size.

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 tire condition monitoring device mounted on a wheel assembly with a tire and executing wireless signaling to a vehicle body, includes an electric circuit further including a sensor detecting a condition of the tire and a wireless circuit executing wireless signaling to transmit results of detection by the sensor, a DC power supply supplying power to the electric circuit, a pair of power lines connecting the DC power supply and the electric circuit to each other, and inductor elements connected to the paired power lines respectively.

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: A tire valve unit (U) having a tire valve (1) and a tire sensor (2) is mounted on a wheel rim (R). In the tire valve unit, a rigid annular member (collar 30) is secured to an open end of the resilient cylindrical member (20). A housing (40) has an extended portion (42) with a passage (40a) defined therein. The extended portion is engaged with the rigid annular member in the resilient cylindrical member, such that an annular space (S1) is defined between a first engaging portion (21) and a second engaging portion (22). The annular space communicates with outside of the housing through the passage of the extended portion, and introduces air pressure into the annular space, to press the resilient cylindrical member to the rim.

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: In an optical LAN system, an optical connector is provided between the input and output optical fiber cables and each of the node devices. The optical connector includes a movable body (a switch body) having a prism. The movable body is switched selectively between a first position (a first state) at which the input and output optical fiber cables are optically connected to the node device and a second position (a second state) in which the input optical fiber cable and the output optical fiber cable are optically connected to each other in such a manner as to bypass the node device. This arrangement suppresses a network crash by means of a relatively simple configuration.

Abstract: A valve device attachable to a wheel including a tire in a state where the valve device penetrates through an opening of the wheel. The valve device includes a transmitter unit for detecting a condition of the tire and generating a transmission signal indicating the detected condition of the tire, a valve stem extending from the transmitter unit and an elastic member disposed to surround the valve stem. The elastic member has an annular attaching portion having a diameter greater than the diameter of the opening. The valve stem is attached to the wheel by passing the attaching portion through the opening by compressively deforming the attaching portion. The attaching portion includes a recessed portion for facilitating compressively deforming the attaching portion.

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: 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 for a tire condition monitoring apparatus includes a circuit board, circuit components mounted on a main surface of the circuit board, and a transmission antenna that transmits a transmission signal as radio waves. The transmission antenna includes a loop shaped transmission conductor that transmits radio waves. The transmission conductor has a loop plane that is substantially perpendicular to the main surface of the circuit board. When the transmitter is attached to the wheel, the loop plane is substantially perpendicular to a portion of the circumferential surface of the wheel that faces the transmitter. As a result, when the transmitter is attached to the wheel, the radio wave transmission efficiency is effectively prevented from being reduced.

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: An optical LAN includes a master node, a plurality of slave nodes, and a plurality of optical fiber cables to configure a network. Each node transmits optical signals to the network and receives optical signals from the network. Each node includes: a light transmitting portion for transmitting optical signals to the network and an abnormality detecting portion. Based on the output level of a received optical signal, the abnormality detecting portion detects decrease in the light intensity of the light transmitting portion of the node that has transmitted the optical signal. Therefore, the master node acquires occurrence of an abnormality when an abnormality occurs in a light transmitting portion of a slave node in the network.

Abstract: A transmitter for a tire condition monitoring apparatus includes a pressure sensor for detecting of the internal pressure of a tire, a transmission circuit for generating a transmission signal, and a transmission antenna for transmitting the transmission signal as a radio wave. The transmission antenna is a planar antenna and includes a plate-like transmission conductor for transmitting the radio wave. The transmission antenna is configured such that the radio wave transmitted from the transmission conductor becomes a circularly polarized wave. As a result, the transmitter has a superior transmission performance and a reduced size.

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: An ring type optical LAN device includes a master node and a plurality of slave nodes that are interconnected by an optical fiber cable. A plurality of optical bypass transmission lines are provided in correspondence with each one of the slave nodes. Each of the optical bypass transmission lines bypasses the corresponding one of the slave nodes. Each slave node includes an E/O converter and an optical cutoff circuit. Each of the E/O converters is controlled to flash for generating an optical signal, which is transmitted to a network. When any one of the slave nodes fails such that the corresponding E/O converter is maintained in a turned on state, the associated optical cutoff circuit forcibly switches the E/O converter to a turned off state. This suppresses a network crash caused by the failure maintaining the E/O converter in the turned on state.

Abstract: A transmitter, which is operated by a battery, wirelessly transmits data including data that represents the temperature T in a tire and data that represents the voltage V of the battery. A receiver judges whether or not the life of the battery is ending depending on the battery voltage V read from the received data. More specifically, the receiver performs the judgment regarding the life of the battery based on a comparison between the battery voltage V and a variable voltage reference value V0, which is selected in accordance with the temperature T in the tire. The judgment regarding the life of the battery is thus accurately performed.

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.