Tire information detecting apparatus without distortion

• US 7,408,454 B2
• Filed: 08/31/2005
• Issued: 08/05/2008
• Est. Priority Date: 09/09/2004
• Status: Expired due to Fees

• Current Assignee: Alps Alpine Co., Ltd.
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Iijima, Kouta
• Primary Examiner(s): Swarthout; Brent
• Application Number:
  US11/219,918
• Publication Number:
  US 20060049924A1
• Time in Patent Office: 1,070 Days
• Field of Search: 340442-449, 731/464, 731/465
• US Class Current: 340/447
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• CPC Class Codes: B60C 23/0433 Radio signals

Abstract

A tire information detecting apparatus includes an interrogator which transmits an interrogation signal toward a tire in a vehicle at a transmitting timing, and receives a reply signal including tire information at a receiving timing so as to process the signals. A responder is disposed in the tire and has a sensor excited by a predetermined frequency signal for detecting tire information so as to return the reply signal to the interrogator at the receiving timing in responding to the interrogation signal. A mixer unit receives the interrogation signal having a first signal and a second signal which is spaced the predetermined frequency away from the first signal, from the interrogator, and outputs a signal of the frequency difference between the two signals to the responder by mixing the first and second signals.

Claims

1. A tire information detecting apparatus, comprising:

an interrogator which transmits an interrogation signal toward a tire in a vehicle at a transmitting timing, and receives a reply signal including tire information at a receiving timing so as to process the reply signal;

a responder which has a sensor being excited by a predetermined frequency signal to detect the tire information and is disposed in the tire to return the reply signal to the interrogator at the receiving timing in responding to the interrogation signal;

a mixer unit which receives the interrogation signal having a first signal and a second signal which is spaced away from the first signal by an amount equal to the predetermined frequency, from the interrogator, and outputs a signal of the frequency difference between the first and second signals to the responder by mixing the first and second signals, wherein the interrogator includes a first voltage-controlled oscillator for outputting the first signal, a first PLL circuit to which a first reference signal is input and which controls the first voltage-controlled oscillator, a second voltage-controlled oscillator for outputting the second signal, a second PLL circuit to which a second reference signal is input and which controls the second voltage-controlled oscillator, and

wherein the first signal is input to the first PLL circuit, and the signal of the frequency difference between the first and second signals is input to the second PLL circuit, where the signal of the frequency difference between the first and second signals is input to the sensor.

2. The tire information detecting apparatus according to claim 1,

wherein only the first signal is transmitted at the receiving timing.

3. The tire information detecting apparatus according to claim 1,

wherein a level of the first signal is set to be equal to a level of the second signal.

4. The tire information detecting apparatus according to claim 1,

wherein the frequency difference is constant when the first signal changes.