Communications: electrical – Land vehicle alarms or indicators – Internal alarm or indicator responsive to a condition of the...
Reexamination Certificate
1999-12-17
2001-08-14
Hofsass, Jeffery (Department: 2632)
Communications: electrical
Land vehicle alarms or indicators
Internal alarm or indicator responsive to a condition of the...
C340S443000, C073S146500
Reexamination Certificate
active
06275148
ABSTRACT:
This application is based on Japanese Patent Application Nos. 10-370413 filed Dec. 25, 1998 and 11-225421 filed Aug. 9, 1999, the contents of which are incorporated hereinto by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a vehicle wheel information supply device for supplying wheel information relating to a state of a wheel of a vehicle, which device includes a transmitter disposed on the wheel and a receiver disposed on the body of the vehicle. The present invention is also concerned with a wheel tire abnormality indicating device which includes such a wheel information supply device, and an indicator operated in response to an output of the vehicle wheel information supply device, to indicate an abnormality of a tire of the vehicle wheel.
2. Discussion of the Related Art
JP-U-5-13802 discloses an example of such kind of vehicle wheel information supply device in the form of a tire air pressure information supply device adapted to supply tire air pressure information indicating whether an air pressure in a tire of a wheel of an automotive vehicle is normal or not. This tire air pressure information supply device includes an air pressure detector disposed on the vehicle wheel to detect the air pressure of the wheel tire, an air pressure information transmitter also disposed on the vehicle wheel to transmit the tire air pressure information, and an air pressure information receiver disposed on the vehicle body to receive the tire air pressure information transmitted by the air pressure information transmitter. Based on an output of the air pressure detector, the air pressure information transmitter intermittently transmits a pulse signal of a predetermined pattern when the output indicates that the tire air pressure is normal, and continuously transmits a pulse signal of another predetermined pattern when the output indicates that the tire air pressure is abnormal. Thus, the air pressure information transmitter in the tire air pressure information supply device described above is adapted to transmit a pulse signal in different patterns where the tire air pressure is normal and where it is abnormal.
The air pressure information receiver disposed on the vehicle body includes a receiving portion including an antenna. The air pressure information transmitter disposed on the vehicle wheel is rotated with the vehicle wheel, so that a distance between this transmitter and the receiving portion of the air pressure information receiver periodically changes, causing a periodic change in the amplitude or intensity of the signal received by the receiver. When the distance is relatively large, the signal-to-noise ratio (SN ratio) is relatively low, and the receiver may not receive the signal whose intensity is high enough to correctly represent the air pressure information. Where the time period required for the transmitter to transmit the air pressure information is relatively long, the probability of incorrect reception of the information is lower due to an influence of the noise on a part of the information than where the time period is relatively short. Accordingly, the probability of correct reception of the entire information by the receiver (“reception ratio”) is lowered with an increase in the time period of the transmission. In the tire air pressure information supply device disclosed in the above-identified publication, the time period of the transmission where the tire air pressure is normal is the same as that where the tire air pressure is abnormal. The reception ratio is lower when the rotating speed of the vehicle wheel is relatively high than when the rotating speed is relatively low, provided the time period of the transmission and the noise level are constant. This is because the ratio of the time period required to transmit a series of the air pressure information to the time period required for one revolution of the wheel increases with an increase in the rotating speed of the wheel.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to provide a vehicle wheel information supply device capable of increasing, as needed, a ratio of reception by a receiver disposed on the vehicle body, of vehicle wheel information transmitted from a transmitter disposed on a wheel of the vehicle.
Another object of the invention is to provide a vehicle wheel tire abnormality indicating device which includes such a vehicle wheel information supply device.
One of the above objects may be achieved according to any one of the following modes of the invention, each of which is numbered like the appended claims and depends from the other mode or modes, where appropriate, to indicate possible combinations of elements or technical features. However, it is to be understood that the invention is not limited to the modes described below and that any one of technical features recited in any one of the modes may be a subject matter of this invention.
(1) A vehicle wheel information supply device for supplying wheel information relating to a state of a wheel of a vehicle, including a wheel state detector for detecting the state of the wheel, a wheel information generator for generating the wheel information relating to the state of the wheel, on the basis of an output of the wheel state detector, a transmitter for transmitting the wheel information, and a receiver which receives the wheel information transmitted by the transmitter, the wheel state detector, the wheel information generator and the transmitter being disposed on the wheel while the receiver being disposed on a body of the vehicle, wherein the wheel information generator is capable of selectively generating different kinds of wheel information having respective different volumes, and at least one of the wheel information generator and the transmitter operates in a manner which changes depending upon at least one parameter indicative of the state of the wheel, which at least one parameter is detected by the wheel state detector.
In the vehicle wheel information supply device, the wheel information relating to the state of the vehicle wheel is generated by the wheel information generator on the basis of the output of the wheel state detector, and is transmitted by the transmitter to the receiver disposed on the vehicle body. The wheel information generator is capable of selectively generating different kinds of wheel information having respective different volumes. At least one of the wheel information generator and the transmitter operates in a manner depending upon at least one parameter indicative of the wheel state detected by the wheel state detector. Namely, at least one of the information generating mode of the wheel information generator and the information transmitting mode of the transmitter is changed depending upon the at least one parameter detected by the wheel state detector, such as the tire air pressure and temperature and the rotating speed of the wheel.
For instance, the wheel information generator generates the wheel information such that the volume of the generated wheel information changes depending upon the detected at least one parameter indicative of the wheel state, such as the tire air pressure or the rotating speed of the wheel. For example, the volume of the generated wheel information is made smaller when the detected tire air pressure is lower than a predetermined threshold, than when the tire air pressure is not lower than the threshold. Alternatively, the volume of the generated wheel information is made smaller when the detected wheel speed is higher than a predetermined threshold, than when the wheel speed is not higher than the threshold. The volume of the wheel information generated by the wheel information generator may decrease with a decrease in the tire air pressure or an increase in the rotating speed of the wheel.
When the volume of the wheel information generated by the wheel information generator is relatively small, the time required for the transmitter to transmit the generated wheel information is shorter, resulting in a high
Banno Mitsuyuki
Katou Mitiya
Ooe Junzo
Takamura Yoshinori
Tsuchiya Takayuki
Hofsass Jeffery
Oliff & Berridg,e PLC
Toyota Jidosha & Kabushiki Kaisha
Tweel , Jr. John
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