Transmitter and external controller of tire inflation pressure monitor

• US 6,340,929 B1
• Filed: 11/15/1999
• Issued: 01/22/2002
• Est. Priority Date: 11/19/1998
• Status: Expired due to Term

• Current Assignee: Pacific Industrial Company Limited
• Original Assignee: Pacific Industrial Company Limited
• Inventors: Momose, Akira, Katou, Michiya, Sawafuji, Kazunori
• Primary Examiner(s): POPE, DARYL C
• Application Number:
  US09/439,681
• Time in Patent Office: 799 Days
• Field of Search: 340/442, 340/445, 340/447, 340/448, 340/449, 731/465, 731/468
• US Class Current: 340/447
• CPC Class Codes: B60C 23/0433 Radio signals
• CPC Class Codes: B60C 23/0479 Communicating with external units being not part of the vehicle, e.g. tools for diagnostic, mobile phones, electronic keys or service stations

Abstract

A transmitter of a tire inflation monitor performs wireless transmission of data concerning tire inflation pressure from an antenna coil to a receiver. The transmitter includes a signal generation circuit, which is connected to the antenna coil. The signal generation circuit generates a trigger signal for activating or inactivating a controller of the transmitter based on a particular control signal received from a predetermined external controller through the antenna coil. When the controller is activated by the trigger signal, the transmitter starts wireless transmission of the data. When the controller is deactivated by the trigger signal, the transmitter is in a sleep state. In this way, data transmission from the transmitter is easily and externally started or stopped.

Claims

1. A tire pressure monitoring apparatus comprising:

a wheel transmitter for wirelessly transmitting data concerning vehicle tire inflation pressure, the wheel transmitter including;

a wheel-mounted antenna;

a pressure sensor for measuring the tire inflation pressure of an associated tire;

a wheel-mounted transmission circuit for sending data that includes data representing the measured tire inflation pressure to the wheel-mounted antenna;

an internal controller for controlling the pressure sensor and the wheel-mounted transmission circuit;

a signal generation circuit, which is connected to the wheel-mounted antenna, wherein the signal generation circuit generates a trigger signal for activating or deactivating data transmission from the wheel-mounted transmission circuit based on a particular trigger signal received through the wheel-mounted antenna, wherein the signal generation circuit sends the trigger signal to the internal controller; and

an external control unit for controlling the wheel transmitter, the external control unit including;

a wireless control unit-mounted transmission antenna;

an operation switch;

an oscillator, which generates the particular trigger signal for activating or deactivating the transmission of data from the wheel transmitter when the operation switch is turned on; and

control unit-mounted transmission circuit, which demodulates and sends the generated particular trigger signal to the control unit-mounted transmission antenna, wherein the particular trigger signal is transmitted from the control unit-mounted transmission antenna to the wheel-mounted antenna when the control unit-mounted transmission antenna is positioned close to or in contact with the wheel-mounted antenna.

2. A transmitter for performing wireless transmission of data concerning tire inflation pressure of a tire supported by a vehicle wheel, the transmitter comprising:

a main body, which is located inside the tire;

a valve stem, which extends from the main body through the wheel;

a removable cap, which is attached to the distal end of the valve stem;

an antenna coil, which is embedded in the cap;

a pressure sensor, which is located in the main body to measure the tire inflation pressure; and

a transmission circuit, which is located in the main body, wherein the transmission circuit sends data that includes data representing the measured tire inflation pressure to the antenna coil through the valve stem for wireless transmission from the antenna coil.

3. The transmitter according to claim 2, wherein the valve stem is made of conductive material, the cap includes a conductive cylinder, which is fitted around and electrically connected to the valve stem, and an insulator covering the cylinder, wherein the antenna coil is embedded in the insulator to surround the cylinder, and the antenna coil is electrically connected to the cylinder.

4. The transmitter according to claim 3, wherein the valve stem includes a male thread and the cylinder includes a female thread that engages the male thread.

5. A transmitter for performing wireless transmission of data concerning vehicle tire inflation pressure, the transmitter comprising:

a transmission antenna;

a pressure sensor for measuring the tire inflation pressure;

a transmission circuit for sending data that includes data representing the measured tire inflation pressure to the antenna for wireless transmission;

a controller for controlling the pressure sensor and the transmission circuit;

a signal generation circuit, which is connected to the antenna, wherein the signal generation circuit generates a trigger signal for activating or deactivating data transmission from the transmission circuit based on a particular signal received through the antenna, wherein the signal generation circuit sends the trigger signal to the controller;

a valve stem that projects from a wheel supporting the tire, wherein the valve stem is made of conductive material; and

a removable cap, which is attached to the distal end of the valve stem, wherein the antenna is an antenna coil embedded in the removable cap, and the cap includes a conductive cylinder, which is fitted around and electrically connected to the valve stem, and an insulator for covering the cylinder, wherein the antenna coil is embedded in the insulator to surround the cylinder and is electrically connected to the cylinder.

6. The transmitter according to claim 5, wherein the signal generation circuit includes:

a tuning circuit, which selects only a particular signal from signals received through the antenna;

a detection circuit, which demodulates the selected particular signal; and

a shaping circuit, which shapes the demodulated particular signal into a predetermined trigger signal.

7. The transmitter according to claim 5, wherein the controller is activated or deactivated based on the reception of the trigger signal.

8. The transmitter according to claim 7, wherein the controller, when active, normally controls the pressure sensor and the transmission circuit such that data is transmitted at predetermined time intervals, and the controller controls the pressure sensor and the transmission circuit such that data transmission is immediately performed when the controller is activated by the trigger signal.

9. The transmitter according to claim 5, wherein the valve stem includes a male thread and the cylinder includes a female thread that engages the male thread.