TIRE INFORMATION DETECTING DEVICE

• US 20080042819A1
• Filed: 04/26/2007
• Published: 02/21/2008
• Est. Priority Date: 04/28/2006
• Status: Abandoned Application

• Current Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Masudaya, Hideki
• Application Number:
  US11/740,718
• Publication Number:
  US 20080042819A1
• Time in Patent Office: Days
• US Class Current: 340/447
• CPC Class Codes: B60C 23/0449 Passive transducers, e.g. using surface acoustic waves, backscatter technology or pressure sensitive resonators near field passive transducers B60C23/0428

Abstract

A tire information detecting device accurately detects tire pressure and temperature. The device includes a transponder mounted in a tire of a vehicle, and a controller located in the vehicle body. The transponder includes a diode, which modulates and demodulates a signal transmitted to and received from the controller, and a pressure measuring unit, which measures a tire pressure. Also included is a detecting resonance circuit connected between the diode and the pressure measuring unit, which resonates in accordance with a signal from the controller. A resonance circuit resonates in accordance with the signal from the controller and controls a connection between the pressure measuring unit and the detecting resonance circuit.

Claims

1. A tire information detecting device, comprising:

a measured value transmitter mounted in a tire of a vehicle;

a controller disposed in a main body of the vehicle configured to transmit and receive a signal to and from the measured value transmitter;

the measured value transmitter including an antenna, a modulator and a demodulator, configured to transmit and receive the signal to and from the controller,

a pressure measuring unit that measures a tire pressure;

a detecting resonance circuit connected between the modulator and the pressure measuring unit, the resonance circuit resonating in response to the signal from die controller;

a connecting resonance circuit configured to resonate in response to the signal from the controller; and

a control circuit configured to control a connection between the pressure measuring unit and the detecting resonance circuit.

2. The tire information detecting device according to claim 1, wherein the control circuit includes a switching element connected to an input-output terminal of the pressure measuring unit on a first signal line, and the pressure measuring unit connected to the detecting resonance circuit by turning on the switching element at the time of resonance of the connecting resonance circuit, wherein the pressure measuring unit is disconnected from the detecting resonance circuit by turning off the switching element at the time of non-resonance of the connecting resonance circuit.

3. The tire information detecting device according to claim 2, wherein the measured value transmitter is operable to transmit a signal of a resonance frequency of the detecting resonance circuit to the controller when the switching element is turned off, and transmit a signal of a resonance frequency of the detecting resonance circuit in accordance with the measurement result of the pressure measuring unit to the controller when the switching element is turned on.

4. The tire information detecting device according to claim 2, wherein the measured value transmitter includes a second signal line configured to bypasses the first signal line between an input-output terminal of the modulator and an input-output terminal of the switching element.

5. The tire information detecting device according to claim 1, wherein the connecting resonance circuit includes an IX resonance circuit.

6. The tire information detecting device according to claim 1, wherein the connecting resonance circuit includes a piezoelectric resonator.

7. The tire information detecting device according to claim 2, wherein the switching element includes a diode.

8. The tire information detecting device according to claim 2, wherein the switching element includes a field-effect transistor.

9. The tire information detecting device according to claim 1, wherein the controller is operable to:

transmit a signal to permit the detecting resonance circuit and the connecting resonance circuit to resonate to the measured value transmitter,

receive a signal of a resonance frequency of the detecting resonance circuit and a signal of a resonance frequency of the detecting resonance circuit in accordance with the measurement result of the pressure measuring unit from the measured value transmitter; and

calculate a temperature and a pressure of the tire based on the resonance frequency of the detecting resonance circuit extracted from the received signal.

10. The tire information detecting device according to claim 9, wherein the controller is operable to calculate the temperature of the tire based on a difference in frequency between the frequency at signal that allows the detecting resonance circuit to resonate and the resonance frequency extracted from the received signal in response to the signal.

11. The tire information detecting device according to claim 9, wherein the controller is operable to calculate the pressure of the tire based on a difference in frequency between the resonance frequency extracted from the received signal and the resonance frequency extracted from the received signal in response to the signal that allows the detecting resonance circuit to resonate in accordance with the measurement result of the pressure measuring unit.

12. The tire information detecting device according to claim 1, wherein the detecting resonance circuit includes a quartz-crystal resonator.