Tire air pressure monitoring system
First Claim
1. A tire air pressure monitoring system for a vehicle comprising:
- a plurality of transmitters provided near tires of a vehicle, each of the transmitters including a tire air pressure sensor for detecting an air pressure of the tire, the transmitter transmitting as a radio wave a transmission signal indicating the air pressure detected by the tire air pressure sensor;
a receiver for receiving the transmission signal from each transmitter so that a tire air pressure of each tire is monitored based on the transmission signal received by the receiver;
the receiver including an antenna element, a variable impedance element coupled to the antenna element, and a power supply source for supplying the antenna element with electric power; and
a directivity control section configured to control directivity of the receiver by controlling a voltage supplied to the variable impedance element.
1 Assignment
0 Petitions
Accused Products
Abstract
A tire air pressure monitoring system has a plurality of sensor units and a receiver. The pressure sensor units are mounted near corresponding tires to measure tire air pressures and transmit transmission signals indicating the respective measured tire air pressures. The receiver has an antenna element, a variable capacitor and a power supply source. The variable capacitor is coupled to the antenna element. The power supply source supplies electric power to the antenna element. The voltage supplied to the variable capacitor is controlled so that a current flowing in the antenna element is changed and its directivity is changed. Thus, the transmission signals will be received more surely.
-
Citations
5 Claims
-
1. A tire air pressure monitoring system for a vehicle comprising:
-
a plurality of transmitters provided near tires of a vehicle, each of the transmitters including a tire air pressure sensor for detecting an air pressure of the tire, the transmitter transmitting as a radio wave a transmission signal indicating the air pressure detected by the tire air pressure sensor; a receiver for receiving the transmission signal from each transmitter so that a tire air pressure of each tire is monitored based on the transmission signal received by the receiver; the receiver including an antenna element, a variable impedance element coupled to the antenna element, and a power supply source for supplying the antenna element with electric power; and a directivity control section configured to control directivity of the receiver by controlling a voltage supplied to the variable impedance element. - View Dependent Claims (2, 3, 4, 5)
-
Specification