JP2003335115A - Tire air pressure detecting device and detected data transmitting method of tire air pressure detecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire air pressure detecting device capable of reducing the probability of the detected data not being received by a monitor device, and providing high reliability on receiving the detected data. <P>SOLUTION: A centrifugal sensor 23 is mounted on sensor devices 14a-14d, and a CPU 25 calculates a rotating period of a tire on the basis of the centrifugal force detected by the centrifugal force sensor 23. The CPU 25 determines a transmission interval of the detected data which is not integral multiple of the rotating period, on the basis of the rotating period, and transmits the detected data of the same contents to the monitor device through a transmitting circuit 19 in accordance with the determined transmission interval. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire pressure detecting device for detecting a tire condition including a tire pressure and transmitting the tire condition as a radio signal, and a detection data transmitting method of the device.

[0002]

2. Description of the Related Art Conventionally, a tire air pressure monitoring device for detecting a tire condition such as a tire air pressure and a temperature, and judging whether or not an abnormality has occurred in the tire based on the detected results to improve the safety of a vehicle. It has been known.

Such a tire air pressure monitoring device is provided with a sensor device (tire pressure detection device) provided on the tire of the vehicle and a monitor device provided inside the vehicle. The sensor device is provided on a tire valve of a tire, and modulates the detected air pressure and temperature data (tire condition) of each tire into a radio wave (radio signal) having a predetermined frequency and transmits the radio wave to the outside. Further, the monitor device receives a radio signal transmitted from the sensor device by a receiving antenna,
The radio signal is demodulated into a pulse signal via the receiving circuit and input to the microcomputer. The microcomputer of the monitor device reads air pressure and temperature data based on the received pulse signal. When the microcomputer determines that the data is abnormal, the microcomputer operates, for example, a display provided on the instrument panel to notify the passenger to that effect.

By the way, in order to increase the reliability of reception of data transmitted as a radio signal, the sensor device continuously transmits data of the same content a plurality of times. And in the past, the data of the same content was transmitted at the same interval. The same interval in this case is a very short time interval such as 20 ms. In this way, by transmitting the data of the same content from the sensor device a plurality of times, the monitor device only needs to receive at least one of the data transmitted a plurality of times, and as a result, the tire abnormality determination can be reliably performed. It was supposed to be done.

[0005]

However, the sensor device constructed as described above has the following problems. That is, as the tire rotates, the sensor device provided on the tire valve also rotates, so the position and angle of the sensor device constantly change, and the monitor device changes the reception intensity of the detection data from the sensor device. . Then, while the sensor device rotates with the tire, there may be a range (so-called null point) in which the reception intensity of the monitor device significantly decreases with respect to the detection data from the sensor device. When the vehicle travels while maintaining a certain speed, the rotation cycle of the tire and the transmission interval of the detection data may coincide with each other, and data with the same content may always be transmitted from the same place. As a result, the data having the same content is transmitted every time the sensor device is positioned in the range of the null point, and the monitor device may not receive any data transmitted a plurality of times.

The present invention has been made in view of the above circumstances, and an object thereof is to reduce the probability that detection data cannot be received in a monitor device and to obtain high reliability in reception of detection data. It is an object of the present invention to provide a tire air pressure detection device and a detection data transmission method of the same.

[0007]

In order to solve the above-mentioned problems, the invention as set forth in claim 1 is a tire condition detecting means for detecting a tire condition including at least tire pressure, and a detection indicating the tire condition. Control means for controlling the data to be transmitted as a radio signal via the transmitting means,
Parameter detection means for detecting a parameter relating to the rotation cycle of the tire, cycle calculation means for calculating the rotation cycle based on the parameter, based on the calculated rotation cycle, the transmission interval of the detection data of the rotation cycle The gist of the present invention is to have setting means for setting the transmission interval of the detection data so that the transmission interval is not an integral multiple.

A second aspect of the present invention is based on the first aspect, wherein the control means controls the same detection data to be continuously transmitted a plurality of times. Claim 3
In the invention according to claim 1 or 2, in which the parameter is a centrifugal force associated with the rotation of the tire, the cycle calculating means calculates the rotation cycle of the tire based on the centrifugal force. Use as a summary.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the control means transmits the detection data in a time shorter than the calculated tire rotation cycle. The main point is to control.

According to a fifth aspect of the present invention, there is provided a tire data detection method for a tire air pressure detection device, which transmits as wireless signals detection data indicating a tire condition including at least tire air pressure detected by the tire condition detecting means. Detecting a parameter relating to the rotation cycle, calculating the rotation cycle based on the parameter, the detection data so that the transmission interval of the detection data is not an integral multiple of the rotation cycle based on the calculated rotation cycle. The point is to set the transmission interval of.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, the tire pressure monitoring device 11 includes first to fourth sensor devices 14 a to 14 d provided on the first to fourth tires 13 a to 13 d of the vehicle 12 and a monitor arranged in the vehicle 12. And a device 15. The first to fourth sensor devices 14a
14d corresponds to a tire air pressure detection device.

(Sensor Device) First to Fourth Sensor Devices 14
a to 14d have the same configuration. Therefore, the configuration of the first sensor device 14a will be specifically described below, and the other second to fourth sensor devices 14b to 14d will be described.
The duplicated description of the configuration will be omitted.

As shown in FIG. 2, the tire valve 1 for injecting air is provided in the rim portion 17 of the wheel 16 of the tire 13a.
8 is provided, and the first sensor device 14a is formed integrally with the tire valve 18.

As shown in FIG. 3, the first sensor device 14a
Is a transmission circuit 19, a micro computer (hereinafter referred to as a first microcomputer 20), an air pressure sensor 21, a temperature sensor 2
2 and a centrifugal force sensor 23.

The air pressure sensor 21 is connected to the first microcomputer 20 and is composed of, for example, a strain gauge or the like so as to detect the air pressure in the first tire 13a. Then, the air pressure sensor 21 outputs air pressure data indicating the detected air pressure to the first microcomputer 20. In addition, the temperature sensor 22
Is connected to the first microcomputer 20 and is configured by, for example, a thermistor or the like so as to detect the temperature inside the first tire 13a. Then, the temperature sensor 22 outputs temperature data indicating the detected temperature to the first microcomputer 20. In the present embodiment, the air pressure sensor 21 and the temperature sensor 22 correspond to the tire state detecting means. Further, the tire air pressure and the tire temperature correspond to the tire state, and the air pressure data and the temperature data correspond to the detection data.

The transmission circuit 19 is connected to the first microcomputer 20, modulates various data output from the first microcomputer 20 into a radio signal (radio wave) of a predetermined frequency, and transmits the radio signal to the outside.
Further, an antenna 24 is connected to the transmission circuit 19, and the antenna 24 transmits the radio signal from the transmission circuit 19 to the outside. The transmitting circuit 19 and the antenna 24 constitute a transmitting means.

The first microcomputer 20 includes a CPU 25 and a ROM
26, RAM 27 and the like. The ROM 26 stores a control program for controlling the first sensor device 14a. The ROM 26 also stores an ID code that is unique to each of the sensor devices 14a to 14d. The RAM 27 has a first
Various data that are appropriately rewritten during the operation of the sensor device 14a are temporarily stored.

Then, according to the control program stored in the ROM 26, the CPU 25 controls to transmit the air pressure data and the temperature data via the transmission circuit 19.
That is, the air pressure data is input from the air pressure sensor 21 and the temperature data is input from the temperature sensor 22 at every predetermined intermittent cycle T1, and the ID code is added to both data (detection data) and output to the transmission circuit 19. And the transmission circuit 1
The air pressure data, the temperature data, and the ID code are transmitted to the outside as radio signals. In the present embodiment, the intermittent cycle T1 is set to about 10 minutes, and the transmission timing of the detection data (radio signal) in each of the sensor devices 14a to 14d including the first sensor device 14a is as shown in FIG. Each is set differently. In addition,
In the following description, the air pressure data and the temperature data may be referred to as “detection data” including the ID code.

By the way, at the transmission timing of the detection data detected in each of the intermittent periods T1, the CPU 25
Transmits the same detection data (hereinafter referred to as the same detection data) a plurality of times (for example, three times) continuously. Then, the CPU 25 performs the transmission so that the transmission interval I of the same detection data transmitted a plurality of times based on the centrifugal force detected by the centrifugal force sensor 23 does not become an integral multiple of the rotation cycle K of the first tire 13a. Set the interval I. In the present embodiment, the transmission interval I is the time from the start of transmission of the same detection data to the start of transmission of the next same detection data. The transmission interval I is, for example, 20
Although it is a very short time as compared with the intermittent cycle T1 such as ms, it is exaggerated in FIG. The rotation cycle K is the time required for the tire 13a to make one rotation. The centrifugal force sensor 23 corresponds to a parameter detecting means, and the centrifugal force corresponds to a parameter. Also, C
PU25 corresponds to a control means, a period calculation means, and a setting means.

Here, the centrifugal force sensor 23 for detecting the centrifugal force will be described in detail. Centrifugal force sensor 23
Is connected to the first microcomputer 20 (CPU 25), detects the centrifugal force generated with the rotation of the first tire 13a, and inputs the centrifugal force data indicating the centrifugal force to the CPU 25. The centrifugal force sensor 23 includes a mass body M1, and detects the centrifugal force based on the force applied to the mass body M1. In the present embodiment, the centrifugal force sensor 23 is
It is composed of a strain gauge type sensor, and the mass body M1 is attached to a strain gauge (not shown). Then, as the first tire 13a rotates, a force (centrifugal force) is applied to the mass body M1, and the strain gauge is distorted accordingly, whereby the centrifugal force is detected. The first sensor device 14a having the centrifugal force sensor 23 is provided with the wheel 16
Is integrally formed with a tire valve 18 provided on the rim portion 17. Therefore, the detected centrifugal force is, as shown in FIG. 2, the centrifugal force at the position of the rim portion 17 of the wheel 16, that is, at the position separated from the center C of the first tire 13a by the radius of the wheel 16.

(Monitoring Device 15) As shown in FIG. 1, the monitoring device 15 includes a receiving antenna 31, a receiving circuit 32, a microcomputer (hereinafter referred to as a second microcomputer 33), and a display 34.

The reception antenna 31 is connected to the reception circuit 32 and is capable of receiving radio signals (detection data) from the first to fourth sensor devices 14a to 14d. The reception circuit 32 demodulates the radio signal received by the reception antenna 31 into a pulse signal and outputs the pulse signal to the second microcomputer 33.

The second microcomputer 33 is a CPU (not shown),
It is composed of a CPU unit including a ROM and a RAM. In addition, the second microcomputer 33 has a tire 13a.
The reference data of 13d are stored in advance. The reference data is a value indicating a normal value such as the air pressure or temperature of the tires 13a to 13d, and is set with a predetermined range. Then, the second microcomputer 33 determines that the air pressure data and the temperature data included in the input pulse signal are normal if they are within the range of the reference data, and determines that they are abnormal if they are outside the range of the reference data. , And outputs an operation signal to the display 34.

The display 34 is provided in the interior of the vehicle 12 (for example, an instrument panel or the like), and is an indicator that indicates when an abnormality occurs in the tires 13a to 13d. The display 34 is connected to the second microcomputer 33 and displays based on an operation signal from the second microcomputer 33.

Next, the first to fourth parts configured as described above
The operation of the sensor devices 14a to 14d will be described. In addition, the 1st-4th sensor apparatus 14a-14 which has the same structure
Since the actions of d are all the same, the first sensor device 14
The operation of a will be described to explain other second to fourth sensor devices 14b.
The duplicated description of ˜14d will be omitted.

Now, after the intermittent period T1 has elapsed from the start of the transmission of the detection data detected last time, the first sensor device 14
The CPU 25 of “a” includes the air pressure sensor 21 and the temperature sensor 2
Input the current air pressure data and temperature data from 2.
Then, ID is added to the detected air pressure data and temperature data.
A code is added, and the same detection data (air pressure data, temperature data, ID code) is controlled to be transmitted a plurality of times according to a control program stored in the ROM 26. That is, first, the CPU 25 inputs the centrifugal force data indicating the present centrifugal force applied to the mass body M1 from the centrifugal force sensor 23. Then, the CPU 25 calculates the rotation cycle K according to the following arithmetic expression (A).

[0027]

[Equation 1] Note that r represents the distance from the center of the tire 13a to the position where the mass body M1 (sensor device 14a) is disposed, that is, the radius of the wheel 16, m represents the mass of M1, and F represents the centrifugal force. The radius of the wheel 16 and the mass M1
Since the mass of is a predetermined value, the present rotation cycle K is calculated by substituting the detected centrifugal force in the arithmetic expression (A). Further, the arithmetic expression (A) is obtained by calculating the angular velocity ω of the mass body M1 during the rotation of the first tire 13a.
Is derived from the equation that represents the centrifugal force acting on the mass body M1. That is, the angular velocity ω of the mass body M1 is expressed by the following equation (1).

Ω = 2πr / K (1) Further, the centrifugal force F is expressed by the following equation (2). F = mrω ² (2) By substituting the equation (1) into the equation (2) and rearranging the equation (A), the arithmetic equation (A) can be derived.

Now, the CPU 25, which has calculated the rotation cycle K by the above-mentioned arithmetic expression (A), sets the transmission interval I based on this rotation cycle K. Specifically, in this embodiment,
The CPU 25 multiplies the rotation cycle K by 1.3 and sets the calculated time (1.3 × K) as the transmission interval I. For example, when the rotation cycle K of the first sensor device 14a is calculated to be 20 ms, the transmission interval I is 26 ms.

Then, the CPU 25 transmits the same detection data a total of three times with the calculated transmission interval I, and the transmission circuit 19
Then, the transmission circuit 19 modulates the same detection data into a radio signal and transmits the radio signal three times. The same detection data is set to a length such that the data transmission time S is sufficiently shorter than the rotation cycle K (for example, 5 ms), and the CPU 25 outputs the same detection data from the rotation cycle K. The transmission circuit 19 is configured to transmit in a short data transmission time S.
To control. Further, since the transmission interval I is calculated based on the centrifugal force detected when the intermittent cycle T1 has elapsed, the transmission interval I is set every time the intermittent cycle T1 has elapsed and new detection data is transmitted. To be done.

Here, the rotation cycle K of the first tire 13a,
The relationship between the null point and the same detection data transmitted at each transmission interval I will be described. It should be noted that the null point means that the first sensor device 14a provided on the tire valve 18 is the first.
While rotating with the tire 13a, the first sensor device 1
It is a position (range) where the reception intensity of the monitor device 15 (reception antenna 31) significantly decreases with respect to the detection data (radio signal) from 4a. In addition, the reception intensity is a radio wave (radio signal) from the reception antenna 31 for a radio wave of the same strength.
Is easy to receive. If the reception strength is high, it is easy to receive the wireless signal, and if the reception strength is low, it is difficult to receive the wireless signal.

If the null point exists, the result shown in FIG.
As shown in, in the rotation cycle K of the first tire 13a, there is a time zone N that is a null point. The time zone N that is the null point is a time zone in which the first sensor device 14a is located in the range that is the null point in the rotation cycle K,
The time is 1 ms or less. Then, a case will be described below in which the transmission time of the same detection data for the first time out of three times of transmission coincides with the time zone N which is the null point.

Under the above premise, the first identical detection data is transmitted when the first sensor device 14a is located at the null point (at t1), and the data transmission time S becomes the null point. It overlaps with time zone N. Therefore, the receiving antenna 31 of the monitor device 15 does not normally receive the same detection data for the first time. However, the same detection data for the second time
Since the data is transmitted after the time corresponding to the transmission interval I set based on the rotation cycle K has passed (at t2), it is transmitted from a position deviating from the null point (at a timing different from the time zone N which is the null point). ) Sent.

When the above-mentioned numerical values are applied concretely, the first sensor device 14a waits for 20 ms (= rotation cycle K) (t3) from the start of the first transmission of the same detection data (t1) for 1 ms. It is located again at the null point. On the other hand, the second identical detection data from the first sensor device 14a is transmitted after 26 ms (= transmission interval I) (at t2). As a result, the transmission time of the same detection data (data transmission time S) does not match the time zone N that becomes a null point that occurs again after the rotation cycle K has elapsed.

Also for the third identical detection data, since this data is transmitted after the time corresponding to the set transmission interval I has passed (at t4), it is detected from a position outside the null point (null It is transmitted at a timing different from the point time zone N). When the above-mentioned numerical values are specifically applied, the first sensor device 14a sets the time of 5 ms after 40 ms (= rotation period K × 2) (t5) from the start of the first transmission of the same detection data (t1). It is located at the null point again. On the other hand, 3 from the first sensor device 14a
The second identical detection data is transmitted after 52 ms (= transmission interval I × 2) (at t4). As a result, the transmission time of the same detection data (data transmission time S) does not match the time zone N that becomes a null point that occurs again after the rotation cycle K has elapsed.

In this way, any one of the same detection data transmitted a plurality of times is detected by the first sensor device 14a at the transmission interval I calculated from the current rotation cycle K based on the centrifugal force. Even if the data is transmitted from the null position, the same data is not repeatedly transmitted from the same position. Therefore, the monitor device 15 is different from the conventional one.
The probability that the detection data cannot be received at is reduced.

Therefore, according to the above embodiment, the following effects can be obtained. (1) In the above embodiment, the rotation cycle K of the tires 13a to 13d is calculated, and based on the rotation cycle K, the transmission interval I of the same detection data is set so as not to be an integral multiple of the rotation cycle K. Therefore, even if the vehicle 12 travels at a predetermined speed, the tires 13a to 13d
The rotation period K of 1 does not coincide with the transmission interval I of the same detection data. Therefore, even if the same detection data is transmitted from the position where the first sensor device 14a is the null point, the next same detection data transmitted with the transmission interval I is repeatedly detected from the same position. It can be prevented from being sent. As a result, the probability that the detection data cannot be received by the monitor device 15 is reduced, and high reliability for reception of the detection data can be obtained.

(2) In the above embodiment, when the detection data of the same content (the same detection data) are continuously transmitted a plurality of times in a short time in order to improve the reliability of reception of the detection data, the transmission interval I Was set so as not to be an integral multiple of the rotation cycle K. Therefore, when the same detection data is transmitted a plurality of times, its reliability can be further improved.

(3) In the above embodiment, the tires 13a-
The centrifugal force accompanying the rotation of 13d was detected, and the rotation cycle K was calculated based on the centrifugal force. Centrifugal force is applied to tires 13a-13
This is a parameter that is always generated during the rotation of d, and since the relationship with the rotation cycle K can be derived, the rotation cycle K can be easily
Can be calculated.

(4) In the above embodiment, the data transmission time S of the detection data is set to be sufficiently shorter than the rotation cycle K. For example, considering the case where the data transmission time S is longer than the rotation cycle K, the detection data is transmitted across the time zone N that is the null point, and the detection data is transmitted to the monitor device 15 even if the transmission interval I is set. Therefore, there is a possibility that it will not be received normally. Unlike this case, the configuration of setting the transmission interval I based on the rotation cycle K can be effectively used.

(5) In the above embodiment, the transmission interval I of the same detection data is set every time the intermittent cycle T1 elapses, that is, each time the newly detected detection data is transmitted. Therefore, each time the same detection data is transmitted, an appropriate transmission interval I corresponding to the rotation cycle K of the tires 13a to 13d at that time can be set.

The above embodiment may be modified as follows. In the above embodiment, the centrifugal force sensor 23 is composed of the strain gauge type sensor, but it may be composed of the piezoelectric type sensor. In this case, the mass body M1 is attached to a piezoelectric element (not shown). Then, a force (centrifugal force) is applied to the mass body M1, and a mechanical stress is generated in the piezoelectric element accordingly, and the centrifugal force is detected. Even in this case, the centrifugal force can be preferably detected. Further, the centrifugal force sensor 23 may be composed of a sensor capable of measuring another force.

In the above embodiment, the transmission interval I is set every time the intermittent cycle T1 elapses from the start of the transmission of the detection data detected last time. However, a predetermined time is set, and the centrifugation is performed every time the time elapses. The force may be detected and the transmission interval I may be set.

In the above embodiment, the detection data is set such that the data transmission time S is sufficiently shorter than the rotation cycle K, but at least the data transmission time S is shorter than the rotation cycle K. (S <K), more specifically, it may be set so as to be shorter than the time obtained by subtracting the null time zone N from the rotation cycle K.

If the detected data becomes long, C
The PU 25 is configured to divide the same detection data and transmit the divided detection data in plural times, and the data transmission time S for one time is the rotation cycle K.
It should be shorter than this.

In the above embodiment, the first to fourth sensor devices 14a to 14d transmit the detection data of the same content a plurality of times according to the set transmission interval I, but different detection data are transmitted according to the transmission interval I. It may be configured to.

In the above embodiment, the number of times the same detection data is transmitted is three, but it may be two or four or more. In the above-described embodiment, the rotation cycle K is calculated based on the centrifugal force, but other parameters generated with the rotation of the tires 13a to 13d may be detected and the rotation cycle K may be calculated based on the detected parameters.

In the above embodiment, the sensor device 14
The number of a to 14d is not limited to four, and the tire 1 of the vehicle 12
You may increase or decrease according to the number of 3a-13d. Further, the sensor devices 14a to 14d are connected to all the tires 1 of the vehicle 12.
3a to 13d need not be provided.

In the above embodiment, the rotation cycle K is 1.3.
The calculated time is set as the transmission interval I, but the value to be multiplied may be appropriately changed, such as 1.5 or 0.5, if it is not an integer. Further, instead of calculating the transmission interval I by multiplying the rotation cycle K by a certain value, the transmission interval I may be calculated by addition or subtraction such as adding or subtracting a value for the rotation cycle K. .

Next, the technical ideas that can be understood from the above-described embodiment and the respective examples will be described below together with their effects. (A) The tire air pressure detection device according to any one of claims 1 to 4, wherein the setting means sets the transmission interval of the set detection data for each elapse of a predetermined duration time. . In the above embodiment, the intermittent cycle T1 corresponds to the duration.

(B) The tire pressure detecting device according to any one of claims 1 to 4 and the receiving means capable of receiving the radio signal transmitted from the device,
A tire air pressure monitoring device, comprising: a tire air pressure monitoring device having a judging means for judging a tire abnormality corresponding to the tire air pressure detecting device based on detection data indicating a tire condition included in the wireless signal. In the above embodiment, the receiving circuit 32 corresponds to the receiving means, and the second microcomputer 3
3 corresponds to the determination means.

[0052]

As described in detail above, according to the present invention,
The probability that the detection data cannot be received by the monitor device can be reduced, and high reliability can be obtained for the reception of the detection data.

[Brief description of drawings]

FIG. 1 is a schematic plan view of a vehicle provided with a tire pressure monitoring device.

FIG. 2 is a side view showing a tire.

FIG. 3 is a block diagram showing an electrical configuration of a sensor device.

FIG. 4 is a timing chart showing the transmission timing of detection data transmitted from each sensor device.

FIG. 5 is a timing chart showing a relationship between a tire rotation cycle and a detection data transmission interval.

[Explanation of symbols]

13a to 13d ... First to fourth tires, 19 ... Transmission circuit (transmission means), 21 ... Air pressure sensor (tire state detection means), 22 ... Temperature sensor (tire state detection means), 23
... Centrifugal force sensor (parameter detection means), 25 ... CPU
(Control means, cycle calculation means, setting means).

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiromitsu Mizuno             260-chome, Toyota, Oguchi-cho, Niwa-gun, Aichi             Tokai Rika Electric Co., Ltd. (72) Inventor Fumio Umeda             260-chome, Toyota, Oguchi-cho, Niwa-gun, Aichi             Tokai Rika Electric Co., Ltd. F term (reference) 2F055 AA12 BB19 CC60 DD20 EE40                       FF34 GG31

Claims (5)

[Claims] 1. A tire condition detecting means for detecting a tire condition including at least a tire pressure, a control device for controlling detection data indicating the tire condition to be transmitted as a wireless signal via a transmitting device, and Parameter detecting means for detecting a parameter related to a rotation cycle, cycle calculating means for calculating the rotation cycle based on the parameter, and transmission intervals of the detection data based on the calculated rotation cycle are integer multiples of the rotation cycle. And a setting means for setting the transmission interval of the detection data so as not to be satisfied. 2. The tire air pressure detection device according to claim 1, wherein the control unit controls so that the same detection data is continuously transmitted a plurality of times. 3. The method according to claim 1, wherein the parameter is a centrifugal force associated with the rotation of the tire, and the cycle calculating means calculates the rotation cycle of the tire based on the centrifugal force. The tire pressure detection device according to. 4. The control unit controls to transmit the detection data in a time shorter than the calculated rotation cycle of the tire. The tire pressure detection device according to. 5. A detection data transmission method of a tire air pressure detection device for transmitting, as a radio signal, detection data indicating a tire condition including at least tire air pressure detected by a tire condition detecting means, and detecting a parameter relating to a tire rotation cycle. Then, after calculating the rotation cycle based on the parameter, the transmission interval of the detection data is set based on the calculated rotation cycle so that the transmission interval of the detection data is not an integral multiple of the rotation cycle. A method for transmitting detection data of a tire pressure detection device, comprising: