JP4076290B2 - Tire condition monitoring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a device for monitoring the state of tire pressure and the like, and more particularly to a tire state monitoring device that enables tire data to be supplied to a driver immediately after the start of traveling.
[0002]
[Prior art]
Conventionally, as a device that constantly monitors tire air pressure, a sensor module equipped with a pressure sensor, transmitter and battery is attached to the wheel, and the pressure sensor data is sent from the transmitter while this data is attached to the vehicle. For example, a system is used in which a receiver receives the information and displays the information on an appropriate display device.
[0003]
In the tire pressure monitoring apparatus, current control is performed by a centrifugal switch in order to extend the battery life of the sensor module. In other words, the centrifugal switch is set to be turned off when the vehicle is stopped, and the sensor module circuit is not operated while the vehicle is stopped, and no data is transmitted, so that it is possible to suppress battery consumption. .
[0004]
However, in the tire pressure monitoring device that performs current control with the centrifugal switch, data is not transmitted until the speed at which the centrifugal switch operates is reached, so even if an abnormality such as puncture occurs while the vehicle is stopped, Otherwise, there was a problem that the driver was not warned. Such abnormal data is preferably warned to the driver before the start of travel or immediately after the start of travel.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a tire condition monitoring apparatus that can supply tire data to a driver immediately after the start of traveling.
[0006]
[Means for Solving the Problems]
A tire condition monitoring device of the present invention that achieves the above object includes a sensor that measures a physical quantity in a tire, a transmitter that transmits data from the sensor, a control circuit that controls operations of the sensor and the transmitter, A power supply for supplying power to the control circuit, a vibration switch for detecting vibration of the tire, a centrifugal switch for detecting centrifugal force generated by rotation of the tire, and a receiver for receiving data transmitted from the transmitter And the control circuit performs data collection by the sensor and data transmission by the transmitter when either the vibration switch or the centrifugal switch is on, and controls the transmission timing of the transmitter to the control circuit. characterized in that the collision prevention timer provided, the vibration switch which is activated only when the vehicle starts, the centrifugal switch is operated only when the vehicle is traveling To.
[0007]
In this way, in a device that constantly monitors the physical quantity (air pressure, temperature, etc.) in the tire, vibration is detected at the start of tire rotation using a vibration switch with higher sensitivity than the centrifugal switch, and data from the sensor is used when the vibration occurs. Since collection and data transmission by the transmitter are performed, tire data can be supplied to the driver immediately after the start of traveling. Therefore, when there is an abnormality in the tire, the driver can stop driving before the speed increases, thereby preventing an unnecessary accident.
[0008]
In addition, when a sensor module including a sensor, a transmitter, and a vibration switch is mounted on each of a plurality of wheels, and transmission data is received by a common receiver, the vibration switch having a high detection sensitivity as described above has a plurality of transmissions. Simultaneous transmission of data from the device may cause interference. Therefore, by incorporating a collision prevention timer in the control circuit and controlling the initial transmission timing when the vibration switch detects the start of rotation of the tire, it is possible to avoid collision of transmission radio waves from the plurality of sensor modules.
[0009]
In the present invention, the receiver is configured to operate with an auxiliary power supply even when the ignition switch is off, and when the receiver receives data from the transmitter during the off period of the ignition switch, it is determined that the tire is stolen. It is also possible to issue a theft alarm. In this case, a function as an antitheft device can be added to the tire condition monitoring device of the present invention.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 illustrates a tire condition monitoring apparatus according to an embodiment of the present invention. In the figure, a tire condition monitoring device includes a sensor 1 that measures a physical quantity in a tire, a transmitter 2 that transmits data from the sensor 1, a control circuit 3 that controls operations of the sensor 1 and the transmitter 2, While a sensor module including a power source 4 for supplying power to the control circuit 3, a centrifugal switch 5 for detecting the running state of the vehicle, and a vibration switch 15 for detecting tire vibration is mounted on the wheel, The display module having the receiver 6 that receives data transmitted from the vehicle 2 is mounted on the vehicle side.
[0011]
As the sensor 1, a pressure sensor that measures the air pressure in the tire, a temperature sensor that measures the temperature in the tire, or the like can be used. Further, these pressure sensors and temperature sensors may be used in combination, and the temperature sensor data may be temperature compensated using the temperature sensor data in order to eliminate the influence of the pressure change due to the temperature.
The transmitter 2 transmits data by a radio frequency (RF) signal. The antenna of this transmitter 2 is connected to the wheel of the wheel to which the sensor module is attached.
[0012]
The control circuit 3 has a theoretical operation circuit (ALU) 31 for instructing driving of the sensor 1 and the transmitter 2, a random access memory (RAM) 32 for temporarily storing data of the sensor 1, and a setting for setting comparison data. A read only memory (EEPROM) 33, an interval timer 34 for setting an operation interval, a collision prevention timer 35 for controlling the initial transmission timing of the transmitter 2, and a vibration switch controller 36 for controlling the vibration switch 15; And a power supply controller 37 that distributes the power supplied from the power supply 4. When mounting a plurality of sensor modules as a set to a plurality of tires of a vehicle, the collision prevention timer 35 of each sensor module is set so that the initial transmission timings are different from each other. Moreover, a primary battery or a secondary battery can be used for the power supply 4.
[0013]
The centrifugal switch 5 is operated by a centrifugal force generated by tire rotation. That is, the centrifugal switch 5 is off when the vehicle is stopped, but is turned on upon detecting the centrifugal force when the vehicle reaches a predetermined speed. On the other hand, as shown in FIG. 2, the vibration switch 15 has a structure in which the vibrator 15b is housed in the housing 15a, and operates based on relative displacement of the vibrator 15b with respect to the housing 15a. It has become. That is, the vibration switch 15 is off when the vehicle is stopped, but is turned on upon detecting a small vibration accompanying the start of tire rotation when the vehicle starts.
[0014]
When the two switches of the centrifugal switch 5 and the vibration switch 15 are provided as described above, the vibration switch 15 carries detection when the vehicle starts and the centrifugal switch 5 carries detection when traveling. That is, the vibration switch 15 operates only when the vehicle starts, and the centrifugal switch 5 operates only when the vehicle travels . Therefore, the vibration switch 15 so as not to operate in a centrifugal force R due to tire rotation, Ru is mounted on a wheel in a state where the longitudinal direction of the housing 15a was oriented in the tire rotation direction C as shown in FIG.
[0015]
The receiver 6 operates with an auxiliary power supply even when the ignition switch is off, and is configured to constantly update the latest data to the memory. When the receiver 6 receives data from the transmitter 2 while the ignition switch is off, the display module is set to issue a theft alarm. That is, the vibration that occurs during the ignition switch off period is not accompanied by the start of driving, so that it can be determined that the tire is stolen. If the sensitivity of the vibration switch 15 is too high, a false alarm of a theft alarm is likely to occur, but such a false alarm can be avoided by adjusting the sensitivity of the vibration switch 15. Further, an inspection mode switch for turning off the theft alarm may be provided in the receiver 6 in preparation for a tire inspection operation.
[0016]
FIG. 3 shows the control operation of the tire condition monitoring apparatus. That is, after the initial process is performed, when the vibration associated with the start of tire rotation is detected and the vibration switch 15 is raised, the vibration flag is set. When the vibration flag is set, the collision prevention timer 35 is turned on. When the collision prevention timer 35 expires, data is collected by the sensor 1 and data is transmitted from the transmitter 2.
[0017]
On the other hand, when the rising of the vibration switch 15 is not detected, if the centrifugal switch 5 is turned on by the rotational centrifugal force of the tire, it is confirmed whether or not the vibration switch 15 is still on. If the vibration switch 15 is on, the vibration flag is reset, and data collection and data transmission are performed. If the vibration switch 15 is off, the collision prevention timer 35 is turned on. After the collision prevention timer 35 expires, data collection and data transmission are performed.
[0018]
When data transmission is performed, the interval timer 34 is turned on, and the routine is repeated after the interval timer 34 expires. In the stop state, neither the vibration switch 15 nor the centrifugal switch 5 is turned on, so the sleep mode is set, and the system waits until there is a switch input. That is, data collection by the sensor 1 and data transmission by the transmitter 2 are performed only when either the vibration switch 15 or the centrifugal switch 5 is on.
[0019]
In the tire condition monitoring apparatus described above, the traveling state is detected by the two systems of the vibration switch 15 and the centrifugal switch 5, and the data collection by the sensor 1 and the transmitter 2 are performed only when the vibration is generated when the tire starts rotating and when the vehicle is traveling. By performing data transmission according to, consumption of the battery serving as the power source 4 can be suppressed.
[0020]
In addition, tire data can be supplied to the driver immediately after the start of traveling by using the vibration switch 15 that can detect with high sensitivity the vibration associated with the start of rotation of the tire. Therefore, there is no inconvenience that the tire data is not displayed until the speed at which the centrifugal switch is turned on (for example, 20 km / h) as in the prior art.
[0021]
The control circuit 3 of the sensor module is provided with a collision prevention timer 35. When the vibration switch 15 detects the start of rotation of the tire, the initial transmission timing of the sensor 1 is set so that communication from the plurality of sensor modules does not collide. Control. For this reason, even if the vibration switch 15 having high detection sensitivity is used, it is possible to prevent interference of transmission radio waves.
[0022]
【The invention's effect】
As described above, according to the present invention, a sensor that measures a physical quantity in a tire, a transmitter that transmits data from the sensor, a control circuit that controls the operation of the sensor and the transmitter, and the control circuit A power supply that supplies power, a vibration switch that detects tire vibration, and a receiver that receives data transmitted from the transmitter, and the control circuit collects data and transmits data when vibration occurs Thus, tire data can be supplied to the driver immediately after the start of traveling. Therefore, when there is an abnormality in the tire, the driver can stop driving before the speed increases, thereby preventing an unnecessary accident.
[0023]
Further, the tire condition monitoring device of the present invention is configured so that the receiver operates with an auxiliary power source even when the ignition switch is off, and the receiver receives data from the transmitter during the off period of the ignition switch. If an alarm is set to be issued, it is possible to function as an anti-theft device.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing a tire condition monitoring apparatus according to an embodiment of the present invention.
FIG. 2 is a perspective view illustrating a vibration switch used in the present invention.
FIG. 3 is a flowchart showing a control operation of the tire condition monitoring apparatus according to the embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Sensor 2 Transmitter 3 Control circuit 4 Power supply 5 Centrifugal switch 6 Receiver 15 Vibration switch 35 Collision prevention timer

Claims (5)

A sensor for measuring a physical quantity in the tire; a transmitter for transmitting data from the sensor; a control circuit for controlling operations of the sensor and the transmitter; a power supply for supplying power to the control circuit; A vibration switch for detecting vibration; a centrifugal switch for detecting centrifugal force generated by rotation of the tire; and a receiver for receiving data transmitted from the transmitter, wherein the control circuit includes the vibration switch and the centrifugal switch. When any of the above is on, data collection by the sensor and data transmission by the transmitter are performed, a collision prevention timer for controlling the transmission timing of the transmitter is provided in the control circuit, and the vibration switch A tire condition monitoring device that operates only when the centrifugal switch operates only when the vehicle travels . The vibration switch has a structure in which a vibrator is housed in a housing attached to a wheel with a longitudinal direction oriented in a tire rotation direction, and the vibration switch is based on relative displacement of the vibrator with respect to the housing. The tire condition monitoring device according to claim 1, wherein the switch is operated .   The receiver is configured to operate with an auxiliary power supply even when the ignition switch is off, and a theft alarm is generated when the receiver receives data from the transmitter during the ignition switch off period. The tire condition monitoring device according to claim 1 or 2. The tire condition monitoring device according to claim 3, wherein the receiver is provided with an inspection mode switch for turning off the theft alarm during a tire inspection operation. The control circuit includes a theoretical operation circuit that commands the driving of the sensor and the transmitter, a random access memory that temporarily stores data of the sensor, a read-only memory that sets comparison data, and an operation interval. The tire condition monitoring device according to any one of claims 1 to 4, further comprising an interval timer for setting, a vibration switch controller for controlling the vibration switch, and a power supply controller for distributing power supplied from a power source.

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