The present invention relates to a device that detects a tire condition such as an inner pressure or temperature of a pneumatic tire, and more particularly, to a tire condition detection device which can improve the poor reception of an antenna arising from adhesion of snow and/or ice thereto.
Recently, with an increase in safety awareness, there have been proposed various devices that detect with sensors physical values showing the service conditions of a tire such as an inner pressure and temperature of the tire during running to inform a driver of the values or to give a driver a warning (see patent documents 1 and 2, for example).
Such devices that detect the conditions of a tire are arranged such that a radio wave of a signal detected by a sensor placed in the cavity of the tire mounted on a vehicle is received via an antenna mounted on the vehicle body side. Since the strength of the radio wave allowed by Japanese legislation is very weak, the antenna mounted on the vehicle body side is attached to a part of the vehicle body that is a location as near as possible to the tire and faces the tread surface of the tire in order to gain good sensitivity. Therefore, in a snow area, if snow and/or ice splashed from a road surface by the tire rotating adhere to the antenna or an antenna case containing the antenna in winter, the reception of the radio wave is impaired; a problem with the antenna arises such as poor reception.
Patent Document 1: Japanese Patent Application Kokai Publication No. 2003-246221
Patent Document 2: Japanese Patent Application Kokai Publication No. 2003-237327
An object of the present invention is to provide a tire condition detection device capable of improving the poor reception of an antenna arising from adhesion of snow and/or ice thereto.
In order to achieve the above object, a tire condition detection device according to the present invention is arranged such that a sensor detects a condition of a tire mounted on a vehicle, and a radio wave of a detection signal of the tire condition is received via an antenna contained in an antenna case mounted on a body side of the vehicle, the tire condition detection device including heating means that can heat the antenna case.
As described above, the heating means that can heat the antenna case containing the antenna is provided, whereby even if snow and/or ice splashed from a road surface by the tire rotating adhere to the antenna case, the snow and/or ice can be easily melted; therefore, the reception of the radio wave by the antenna is not impaired by the snow and/or ice adhering the antenna case. Accordingly, the poor reception of the antenna arising from adhesion of snow and/or ice can be prevented.
Another tire condition detection device according to the present invention is arranged such a sensor detects a condition of a tire mounted on a vehicle, and a radio wave of a detection signal of the tire condition is received via an antenna directly mounted on a body side of the vehicle, the tire condition detection device including heating means that can heat the antenna.
As described above, when the antenna is directly mounted on the vehicle body side, the heating means that can heat the antenna is provided, whereby snow and/or ice adhering to the antenna can be melted; thus the poor reception of the antenna arising from adhesion of snow and/or ice thereto can be improved.
An embodiment of the present invention will be described in detail below with reference to the attached drawings.
Referring to
The tire side unit 1 includes a pressure sensor 3 for detecting a pressure in the cavity 15a of a tire 15 (see
The vehicle body side unit 2 includes receiving means 10 having a metallic antenna 8 for receiving a radio wave of the detected signal by each of the sensors 3 and 4 transmitted from the antenna 7 and a receiver 9, processing means 11 for processing the detected signal, display means 12 for displaying pressure and temperature values of the detected signals processed by the processing means 11, and heating means 13 that can heat an antenna case 14 described later. The receiving means 10 is connected to the processing means 11, which is connected to each of the display means 12 and heating means 13. The electric power supply of the vehicle is used for each means of the vehicle body side unit 2 as an operation power source.
As shown in
The processing means 11 determines whether a value of the signal of temperature detected by the temperature sensor 4 is equal to or less than a predetermined temperature or not, and if the processing means determines that it is equal to or less than the predetermined temperature, the processing means makes the heating means 13 turned on to heat the antenna case 14. If the vehicle has a temperature sensor that detects outside air temperature, a value of the signal of temperature detected by the temperature sensor of the vehicle may be employed instead of the signal value of temperature detected by the temperature sensor 4. Alternatively, a temperature sensor is attached to the antenna case 14 or antenna 8, and a value of the signal temperature detected by this temperature sensor may be used.
The processing means 11 is preferably structured such that the processing means works in conjunction with a wiper of the vehicle, and only in the case where the wiper switch of the vehicle is on, the processing means makes the heating means 13 turned on. Even if the temperature is low, there is a case such that it does not snow but is a fine weather; therefore, by connecting to the wiper, the heating means 13 can be prevented from unnecessarily working during a fine weather.
The heating means 13 heats the surface 14a of the antenna case 14 to melt snow and/or ice adhering to the surface 14a; the heating means may employ any structure if the structure can melt the snow and ice adhering thereto; the heating means 13 having a heat generation element shown in each of
The heating means 13 shown in
The heating means 13 shown in
The heating means 13 shown in
According to the present invention, since the antenna case 14 containing the antenna 8 can be heated by the heating means 13, even if snow and/or ice splashed from a road surface by the tire 15 rotating adhere to the antenna case 14, the snow and/or ice can be melted, thus preventing the antenna 8 from impairing the reception of the radio wave.
Since the heating means 13 can automatically be turned on by the processing means 11, a driver is not bothered with the operation of the heating means 13.
The above embodiment shows that the antenna 8 is contained in the antenna case 14 and attached to the vehicle part 16; however, the tire condition detection device of the present invention may be one designed such that the antenna 8 is not contained in the antenna case 14 but is directly attached to the vehicle part 16.
In this case, as snow and/or ice adhere to the antenna 8, the heating means 13 is structured so as to be able to heat the antenna 8; the structure may be any one that can melt the snow and/or ice adhering to the surface of the antenna 8.
For example, the heating mans 13 shown in
The processing means 11 may be arranged such that the heating means 13 is turned on when the processing means loses the detected signal received via the antenna 8 instead of the above structure. Alternatively, the processing means may be arranged such that a switch for turning on the heating means 13 is provided in a cockpit, and the heating means 13 is turned on by operation of the switch by a driver.
In the above embodiment, as the tire condition detection device, there is exemplified a device in which pressure and temperature of the tire 15 are detected, and the radio waves of the detected signals are received via the antenna 8 mounted on the vehicle body side; however, the tire condition detection device of the present invention may be any one in which a physical value showing the service conditions of a tire mounted on a vehicle is detected by a sensor, and the detected signal is received on the vehicle body side via the antenna 8.
The tire condition detection device of the present invention having the aforementioned excellent effects can be very effectively utilized as a tire condition detection device that is to be mounted on a vehicle used in a snow area.
Number | Date | Country | Kind |
---|---|---|---|
2004-118745 | Apr 2004 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/JP05/07247 | 4/14/2005 | WO | 00 | 10/3/2006 |