Tire-pressure monitoring device

Patent metadata

Field	Value
Publication number	US-9783011-B2
Application number	US-201614995912-A
Country	US
Kind code	B2
Filing date	Jan 14, 2016
Priority date	Jan 22, 2015
Publication date	Oct 10, 2017
Grant date	Oct 10, 2017

Abstract

A pulse count part acquires the minimum value among the numbers of pulse signals outputted by respective wheel-speed sensors during a wheel speed is within a minute low speed range. The pulse count part sets said minimum value as the numbers of the pulse signals of respective wheel-speed sensors during the wheel speed is within the minute low speed range, when the wheel speed increases out of said minute low speed range. Thereby, even when a vehicle stops in the middle of a wheel location discrimination treatment, a wheel location discrimination treatment can be continued using a proper pulse count value.

First claim

The invention claimed is:

1. A tire-pressure monitoring device comprises:
a plurality of wheel sensors, each of which is fixed to each of wheels of a vehicle and detects a tire pressure of the wheel that it is fixed to, and transmits a tire-pressure information representing the detected tire pressure along with its specific sensor ID as a radio signal, and
a vehicle body side device which is fixed to a vehicle body and performs a notification process for informing a crew member of said vehicle of an information about the tire pressure of each of said wheels, using said sensor ID and said tire-pressure information acquired by receiving said radio signal and a previously memorized relation between said sensor IDs and wheel locations that are locations of said wheels with respect to said vehicle body; and
each of said plurality of wheel sensors is configured to transmit said radio signal at a timing when a sensor turning position which is its turning position around each axle shaft is a predetermined transmitting position, and
said vehicle body side device comprises:
a pulse count means to integrate the number of a pulse signal, which is an output signal of each of a plurality of wheel-speed sensors disposed for each of said wheels and is outputted whenever each of said wheels rotates a predetermined angle, to acquire a pulse count value, for each of said wheel-speed sensors, and
a discrimination means to distinguish said wheel location of said wheel that each of said wheel sensors is fixed to, based on said pulse count values at a point of time when receiving said radio signal transmitted from each of said wheel sensors, and update said previously memorized relation between said sensor IDs and said wheel locations based on the discrimination result, wherein:
said pulse count means comprises:
a speed evaluation means to judge whether a vehicle speed is within a predetermined minute low speed range,
a minimum value acquisition means to integrate the number of said pulse signal which each of said wheel-speed sensors outputs when said speed evaluation means judges that said vehicle speed is within said minute low speed range, for each of said wheel-speed sensors, and to acquire the minimum value among the integrated values, and
a count value adjustment means to update said pulse count value for each of said wheel-speed sensors by setting the number of said pulse signal that each of said wheel-speed sensor had outputted when said vehicle speed was judged to be within said minute low speed range to said minimum value when said vehicle speed increases out of said minute low speed range.

2. The tire-pressure monitoring device according to claim 1 , wherein:
said speed evaluation means is configured to judge that said vehicle speed has fallen within said minute low speed range when the number per unit time of said pulse signal outputted from each of said wheel-speed sensors becomes less than a first set value for all said wheel-speed sensors, and to judge that said vehicle speed has got out of said minute low speed range when the number per unit time of said pulse signal outputted from each of said wheel-speed sensors becomes equal to or larger than a second set value which is larger than said first set value for all said wheel-speed sensors.

Assignees

• Toyota Motor Co Ltd

Inventors

• Taki Yuji

Classifications

• B60C23/0489

  for detecting the actual angular position of the monitoring device while the wheel is turning · CPC title

• B60C23/0433 Primary

  Radio signals · CPC title

• B60C23/0416 Primary

  allocating a corresponding wheel position on vehicle, e.g. front/left or rear/right · CPC title

• B60C23/0488

  Movement sensor, e.g. for sensing angular speed, acceleration or centripetal force · CPC title