JP4153200B2 - Tire pressure detector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tire air pressure detection device that detects a tire air pressure and enables a driver to recognize the tire air pressure even while a vehicle is running.
[0002]
[Prior art]
For example, Japanese Patent Laid-Open No. 10-44726 “Tire Air Pressure Alarm Device” is known as a tire air pressure detection device that enables a driver vehicle to recognize the tire air pressure even while the vehicle is running.
In the above technique, according to FIG. 1 of the publication, a valve stem 10 is attached to a wheel rim 1 (the reference numeral is diverted from the reference numeral), and a case 2 is disposed at the base of the valve stem 10. The tire pressure is measured by placing the pressure detection unit 3, the signal processing circuit 4 and the transmission unit 7 composed of the battery 5 into the tire. When an abnormality is detected in the tire pressure, that is, the tire pressure falls below a predetermined value. This is a tire air pressure warning device that informs the driver when the vehicle is off.
[0003]
[Problems to be solved by the invention]
For example, when the pressure detector 3 is a sensor using a diaphragm or the like, one is opened to the outside and the other is exposed to the inside of the tire. Therefore, the tire pressure may show an inappropriate value depending on the external pressure, which will be described with reference to the next figure.
[0004]
8A and 8B are explanatory views showing an example of a pneumatic sensor used in a conventional tire pressure alarm device. The air pressure sensor is represented by a manometer for convenience, but a commercially available tire pressure gauge may be used.
In (a), the air pressure sensor 101 is a sensor having one opened to the outside and the other facing the inside of the tire 102. The air pressure of the tire 102 is set to 200 kPa as a gauge pressure at a high altitude of an external air pressure of 80 kPa. At this time, the air pressure is 280 kPa in absolute pressure.
[0005]
In (b), the tire 102 having an air pressure of 80 kPa and an air pressure of 200 kPa is moved to a flat ground with an external air pressure of 100 kPa as indicated by the white arrow. The air pressure of the tire 102 does not change at 280 kpa in absolute pressure, but becomes 180 kPa in gauge pressure.
[0006]
In other words, if a vehicle with tire pressure (gauge pressure) set at high altitude with low external air pressure is moved to a flat ground where the external air pressure is higher than that at high altitude, the tire air pressure (gauge pressure) is low by the amount that the external air pressure has increased. Indicates. Conversely, if a vehicle with tire pressure (gauge pressure) set at normal atmospheric pressure is moved to a high altitude where the external air pressure is lower than the flat ground, the tire air pressure (gauge pressure) is increased by the amount that the external air pressure has decreased. Indicates the value.
Therefore, the tire pressure alarm device is intended to issue a warning when the tire pressure (gauge pressure) falls below a predetermined value under a certain condition in both high altitude and flat ground.
[0007]
An object of the present invention is to provide a tire pressure detecting device that issues a warning when a tire pressure falls below a predetermined value under a certain condition.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a first aspect of the present invention relates to a tire pressure detecting device that detects a tire pressure with an air pressure sensor and issues a warning when the tire pressure deviates from a predetermined value. And a pressure conversion means for converting the tire air pressure detected by the air pressure sensor to the pressure at the reference atmospheric pressure based on the external air pressure detected by the external air pressure sensor. It is characterized by subtracting the reference atmospheric pressure of the absolute pressure from the sum of the external air pressure detected by the absolute pressure and the tire air pressure detected by the gauge pressure by the air pressure sensor .
[0009]
It is preferable if it is possible to issue a warning when the tire pressure deviates from a predetermined value under a certain condition, regardless of whether it is a high altitude or flat land, by taking into account the fluctuation of the tire pressure due to the influence of the external air pressure. .
Therefore, the external air pressure is detected by the external air pressure sensor, and the tire air pressure detected by the air pressure sensor based on the external air pressure is detected by the external pressure detected by the external air sensor by the pressure conversion means and the gauge pressure by the air pressure sensor. The absolute pressure reference atmospheric pressure was subtracted from the sum of the tire pressure and converted to a pressure at the reference atmospheric pressure. Thus, a warning can be issued when the tire air pressure deviates from a predetermined value under a certain condition regardless of whether it is a highland or a flatland. As a result, the convenience of the tire pressure management for the driver can be improved.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.
FIG. 1 is a side view of a motorcycle equipped with a tire pressure detecting device according to the present invention. A motorcycle 10 includes a vehicle body frame 11 extending toward the lower rear portion of the vehicle, and a head pipe attached to the vehicle body frame 11. 12, a front fork 13 attached to the head pipe 12, a front wheel 14 attached to the front fork 13, a handle 15 connected to the front fork 13, and a rear suspension 16 having one end attached to the rear upper part of the body frame 11. A swing arm 17 swingably mounted between the other end of the rear suspension 16 and the rear lower portion of the vehicle body frame 11, a rear wheel 18 attached to the tip of the swing arm 17, and an upper rear portion of the vehicle body frame 11. Seat 19, engine 22 and transmission 23 disposed below body frame 11. And a power unit 21 consisting of a main constituent and the motorcycle motorized.
[0011]
In the figure, 24 and 25 are axles, 27 is a drive chain cover, 28 is a brake pedal, 29 is a kick pedal, 31 is a leg shield, 32 is a front fender, 33 is a rear fender, 34 is a head lamp, 35 is a tail lamp, 36 Is a rearview mirror, 37 is a meter panel, and 38 is a stand.
Reference numeral 50 denotes a tire air pressure detecting device that detects the tire air pressure and enables the driver to recognize the tire air pressure even while the vehicle is running, as will be described later.
[0012]
FIG. 2 is a side view around the front of a motorcycle equipped with a tire pressure detecting device according to the present invention.
The front wheel 14 includes a wheel 41, a tire 42 attached to the wheel 41, and a tire air pressure detection device 50 for knowing the air pressure of the tire 42.
The wheel 41 includes a disk-shaped disk 45, a wheel rim 46 formed around the disk 45, and an air valve 47 attached to the wheel rim 46.
The rear wheel 18 shown in FIG. 1 is a member having substantially the same configuration as the front wheel 14, and a detailed description thereof is omitted.
[0013]
3 is a cross-sectional view taken along line 3-3 in FIG. 2 and shows a front cross-section of the tire air pressure detection device 50.
The tire air pressure detecting device 50 opens an opening 48 in the wheel rim 46, and a rubber grommet 51 is fitted into the opening 48, and a cored bar 52 is inserted into the grommet 51 to detect the air pressure of the tire 42 and send pressure information to the outside. The grommet 51 holds a transmitter 53 that transmits to the receiver, and a receiver 81 that issues a warning based on pressure information from the transmitter 53 is provided.
[0014]
The transmitter 53 includes an external air pressure sensor 54 embedded inside the wheel rim 46 of the grommet 51 for detecting the external air pressure, an air pressure sensor 55 disposed in the tire 42 for detecting the air pressure of the tire 42, and the air pressure. The tire pressure detected by the sensor 55 is converted into the pressure at the reference atmospheric pressure from the external pressure detected by the external pressure sensor 54, and the pressure converted into the pressure at the reference atmospheric pressure by the pressure conversion means 56 Air pressure determination means 57 for determining whether warning is required based on whether the warning is necessary, or whether attention is required or normal, and a warning signal and attention signal as pressure information based on the result determined by the air pressure determination means 57 Or it comprised from the transmission circuit 58 which transmits the signal which shows that it is normal.
[0015]
In addition, the attachment property to the wheel rim 46 and a sealing performance can be improved by making the grommet 51 into a fitting type. In addition to the holding function of the transmitter 53, the core metal 52 has an antenna function for transmitting pressure information from the transmitter circuit 58 to the receiver 81. The receiver 81 is a unit provided on the meter panel 37 (see FIG. 2) as will be described later.
In the figure, 61 is a battery for driving the transmitter 53, and 62 is a case for collectively storing the pressure conversion means 56, the air pressure judgment means 57, the transmission circuit 58 and the battery 61.
[0016]
FIG. 4 is a plan view of a meter panel in which the receiver of the tire pressure detecting device according to the present invention is housed. The receiver 81 is provided on the meter panel 37 and is transmitted from the transmitter 53 shown in FIG. A receiving circuit 82 for receiving pressure information, an information determining means 83 for determining pressure information received by the receiving circuit 82, and the first light emitting diode 84 when the pressure information determined by the information determining means 83 is a warning signal. The first lighting circuit 87 for lighting, the second lighting circuit 88 for lighting the second light emitting diode 85 when the pressure information determined by the information determining means 83 is a caution signal, and the pressure information determined by the information determining means 83 are normal. The third lighting circuit 89 for lighting the third light emitting diode 86 when the signal indicates that the pressure is determined, and the pressure information determined by the information determining means 83 is a warning signal or a caution signal A buzzer driving circuit 92 to sound the buzzer 91, made of.
[0017]
The first light emitting diode 84 is a diode that emits red light, the second light emitting diode 85 is a diode that emits yellow light, and the third light emitting diode 86 is a diode that emits green light.
Reference numeral 93 denotes a housing that collectively stores the receiving circuit 82, the information determining unit 83, the first to third light emitting diodes, the first to third lighting circuits 87 to 89, the buzzer 91, and the buzzer driving circuit 92.
[0018]
FIG. 5 is a block diagram of a tire air pressure detecting device according to the present invention. The tire air pressure detecting device 50 detects the tire air pressure with an air pressure sensor 55 and issues a warning when the tire air pressure deviates from a predetermined value. In the tire air pressure detecting device, an external air pressure sensor 54 for detecting the external air pressure, and a pressure conversion means for converting the tire air pressure detected by the air pressure sensor 55 to the pressure at the reference atmospheric pressure by the external air pressure detected by the external air pressure sensor 54 56 can be said to be provided.
[0019]
That is, it is preferable to detect the tire air pressure so that the driver can recognize the tire air pressure even while the vehicle is running. At this time, the fluctuation of the tire air pressure due to the influence of the external air pressure is taken into consideration. Thus, it is more preferable if a warning can be issued when the tire air pressure deviates from a predetermined value under a certain condition regardless of whether it is a highland or a flatland.
[0020]
Therefore, the external air pressure is detected by the external air pressure sensor 54, and the tire air pressure detected by the air pressure sensor 55 based on the external air pressure is converted into the pressure at the reference atmospheric pressure by the pressure conversion means 56.
Specifically, it is assumed that the outside air pressure detected by the outside air sensor 54 is P _{10 as} an absolute pressure, and the tire air pressure detected at this time by the air pressure sensor 55 is p _{11 as a} gauge pressure. On the other hand, if the reference atmospheric pressure at an absolute pressure between P _12, tire pressure p ₁₃ after pressure compensation has
p ₁₃ = (P ₁₀ + p ₁₁ ) −P ₁₂ …………………… ▲ 1 ▼
Can be expressed as
[0021]
For example, if the reference atmospheric pressure P ₁₂ is 100 kPa and the tire air pressure p ₁₁ measured at a high altitude where the external air pressure P ₁₀ is 80 kPa is 200 kPa, p ₁₃ = (80 + 200) −100 = 180 kPa from the equation (1). …… ▲ 2 ▼
It becomes.
[0022]
Assuming that the tire air pressure p ₁₁ measured on a flat ground with an external pressure P ₁₀ of 100 kPa is 180 kPa, p ₁₃ = (100 + 180) −100 = 180 kPa.
It becomes.
[0023]
If the tire pressure p ₁₁ measured in a lowland such as a submarine tunnel with an external pressure P ₁₀ of 120 kPa is 160 kPa, p ₁₃ = (120 + 160) −100 = 180 kPa from the formula (1).
It becomes.
[0024]
Thereby, in the said example, the conversion pressure of 180 kPa was able to be obtained irrespective of the ground height. The tire pressure after such conversion is used to issue a warning when the value deviates from a predetermined value under a certain condition. As a result, the convenience of the tire pressure management for the driver can be improved.
[0025]
Next, the operation of the tire air pressure detecting device 50 described above will be described.
FIG. 6 is a flowchart of the tire pressure detecting device according to the present invention. (Refer to FIG. 5 for symbols). STxxx indicates a step number.
ST101: The tire air pressure is detected by the air pressure sensor 55.
ST102: The external atmospheric pressure is detected by the external atmospheric pressure sensor 54.
[0026]
ST103: The detected tire pressure is converted into a tire pressure when the external atmospheric pressure is 1 atm.
ST 104: The tire air pressure converted Pk (corresponding to p ₁₃ which were in the previous description), a first detection value Threshold as a predetermined value under a predetermined condition when the Pk1, tire pressure Pk is the It is determined whether the detected value threshold value Pk1 of 1 is exceeded (Pk> Pk1). If YES, the process proceeds to ST106, and if NO, the process proceeds to ST105.
ST105: It is determined whether the tire air pressure Pk exceeds the second detection value threshold value Pk2 when the second detection value threshold value as a predetermined value under a certain condition is set to Pk2 (Pk> Pk2). ).
[0027]
ST106: A signal indicating that the tire air pressure Pk is normal is transmitted. As a result, the third light emitting diode 86 is lit in green.
ST107: An attention signal is transmitted. As a result, the second light emitting diode 85 is lit yellow and the buzzer 91 sounds.
ST108: A warning signal is transmitted. As a result, the first light emitting diode 84 is lit red and the buzzer 91 sounds.
[0028]
FIG. 7 is a graph showing the characteristics of the tire pressure detecting device according to the present invention, Pk is the tire pressure after pressure correction (converted), Pa is adjusted to the tire pressure on the flat ground (1 atm) and moved to the high ground. The tire pressure is shown.
That is, when pressure correction is not performed, when the motorcycle 10 (see FIG. 1) is moved from a flat ground to a high ground, the tire pressure drifts in a region surrounded by two curves of the tire pressure Pk and the tire pressure Pa. Become. Accordingly, the first inspection value threshold value Pk1 that generates a predetermined attention signal and the second inspection value threshold value Pk2 that generates a warning signal also change, which is not preferable.
[0029]
Therefore, the external air pressure is detected by the external air pressure sensor 54, and the tire air pressure detected by the air pressure sensor 55 based on the external air pressure is converted into the pressure at the reference atmospheric pressure by the pressure conversion means 56. Thus, a warning can be issued when the tire air pressure deviates from a predetermined value under a certain condition regardless of whether it is a highland or a flatland. As a result, the convenience of the tire pressure management for the driver can be improved.
[0030]
In the embodiment, the vehicle has been described as the motorcycle 10 as shown in FIG. 1, but the vehicle is not limited to the two-wheeled vehicle, and the vehicle may be a four-wheeled or three-wheeled vehicle.
In the embodiment, as shown in FIG. 4, the receiver 81 is provided on the meter panel 37, but the present invention is not limited to this. For example, it may be provided on a vehicle body frame, a helmet or the like if an alarm is issued, or on a seat or a helmet if vibration is used. Although receiver 81 has been described as a unit for front wheel 14 (see FIG. 1), it may be a unit that also receives rear wheel 18 at the same time.
[0031]
Further, in the embodiment, as shown in FIG. 5, the external pressure sensor 54 is provided in the grommet 51 of the front wheel 14. However, the present invention is not limited to this, and for example, a sensor that detects the external pressure of the fuel injection device is used. It may be a thing. In this case, the pressure conversion means may be provided on the receiver side for processing.
[0032]
【The invention's effect】
The present invention exhibits the following effects by the above configuration.
According to claim 1, comprising an outer pressure sensor for detecting the external atmospheric pressure, and a pressure conversion means for converting the tire pressure detected by the air pressure sensor by outside air pressure detected by the outside air pressure sensor to the pressure at the reference atmospheric pressure, the outside air Since the reference atmospheric pressure of the absolute pressure is subtracted from the sum of the external air pressure detected by the sensor with the absolute pressure and the tire air pressure detected by the gauge pressure with the air pressure sensor , the tire can be used regardless of whether it is high or flat. A warning can be issued when the air pressure deviates from a predetermined value under certain conditions. As a result, the convenience of the tire pressure management for the driver can be improved.
[Brief description of the drawings]
FIG. 1 is a side view of a motorcycle equipped with a tire air pressure detecting device according to the present invention. FIG. 2 is a side view of a motorcycle around a front surface of a motorcycle equipped with a tire air pressure detecting device according to the present invention. Fig. 4 is a cross-sectional view taken along line 3-3. Fig. 4 is a plan view of a meter panel housing a receiver of the tire pressure detecting device according to the present invention. Fig. 5 is a block diagram of the tire pressure detecting device according to the present invention. FIG. 7 is a flow chart of the tire pressure detecting apparatus according to the present invention. FIG. 8 is a graph showing the characteristics of the tire pressure detecting apparatus according to the present invention.
DESCRIPTION OF SYMBOLS 50 ... Tire air pressure detection apparatus, 54 ... External air pressure sensor, 55 ... Air pressure sensor, 56 ... Pressure conversion means, Pk1, Pk2 ... Predetermined value under a certain condition (first and second detection value threshold values).

Claims (1)

In the tire pressure detection device of the type that detects the tire pressure with an air pressure sensor and issues a warning when the tire pressure deviates from a predetermined value,
The tire air pressure detection device includes an external air pressure sensor that detects an external air pressure, and a pressure conversion unit that converts the tire air pressure detected by the air pressure sensor into a pressure at a reference atmospheric pressure based on the external air pressure detected by the external air pressure sensor, With
The pressure conversion means is such that the reference atmospheric pressure of absolute pressure is subtracted from the sum of the outside air pressure detected by the outside air sensor with absolute pressure and the tire pressure detected by the air pressure sensor with gauge pressure. A tire pressure detecting device.

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