1. Field of the Invention
The present invention relates to a wheel-mounted wheel condition detector that detects the condition of each wheel. The present invention also relates to a wheel condition monitor that monitors the condition of each wheel, the monitor having a wheel-mounted device that transmits information for each wheel and a vehicle-mounted device that receives the information from each wheel.
2. Description of the Related Art
A conventional tire pressure monitoring system (hereinafter referred to as “TPMS”) generally includes a wheel-mounted device and a vehicle-mounted device. The wheel-mounted device is designed to sense tire air pressure (hereinafter sometimes referred to as “tire pressure”) of each wheel. The vehicle-mounted device is designed to acquire information on the tire pressure of each wheel from the wheel-mounted device, and monitor the tire pressure of the wheel (See JP-A-2001-174356).
In the TPMS, a tire pressure sensor as the wheel-mounted device has a detecting section located in an internal space defined between the tire and the wheel member. The detecting section takes the form of a case to accommodate a tire pressure detecting element, a wireless transmitter for transmitting a detection signal of the tire pressure detecting element to the vehicle-mounted device, and so forth. The case has an air passage hole for directing air in the internal space to a specific detection space within the case. The vehicle-mounted device receives the tire pressure information from the wheel-mounted device, and warns the driver (e.g. displays specified alarm information) if the tire pressure is below predetermined reference tire pressure.
However, TPMS-equipped vehicles are not allowed to use a repair liquid for flat tires.
The recent trends show that a traditional spare tire is replaced with a flat tire repair kit including a repair agent, due to the growing demand for a spacious trunk with larger luggage storage capacity or for a roomier compartment to accommodate the three-row seating arrangement.
Generally, the repair of a flat tire is carried out as below, using such flat tire repair kit that includes a bottle of tire repair liquid, a hose connector, and a compressor. The hose connector is used to connect the liquid bottle and an air valve on the wheel. Then, the liquid bottle is manually compressed to inject the tire repair liquid into the tire. Subsequently, the compressor is connected to the air valve to send air into the tire. After that, the vehicle is started to let the tire repair liquid spread all over the inside of the tire.
However, while the vehicle is in motion, the injected tire repair liquid may be scattered within the tire, and enter the case of the tire pressure sensor through the air passage hole of the case. Such liquid may adhere to the tire pressure detecting element or clog the air passage hole.
This phenomena caused by the tire repair liquid may apply not only to the TPMS, but also to any wheel condition detector and wheel condition monitor, in which a detecting section for detecting a wheel condition is provided in an internal space defined between the tire and the wheel member, and the interior and exterior of the detection section are communicated with each other. A sensor for detecting the wheel condition is preferably designed to prevent the entry of a tire repair agent as well as water and other foreign matter.