JPH08219922A - Pneumatic pressure sensor for tire and sensor housing - Google Patents

Abstract

PURPOSE: To decrease the number of components and to facilitate the fixing work by providing a sensor body housing a pressure switch and an oscillator, and a compliant sensor housing comprising a tubular part and a bottom part closing one end thereof with a rim clamping part being provided on the outer circumferential face thereof. CONSTITUTION: The pneumatic pressure sensor 100 for tire comprises a sensor body 101 and a sensor housing 102 wherein the body 101 comprises a base part 101A, and a forward end part 101B having outer diameter larger than that of the base part 101A coupled concentrically each other. The sensor 100 is fixed to the rim 2 of a tire 1 such that a pressure detection means is disposed in the tire 1. Antenna coil 4 of an inner pressure detector for tire is fixed to a brake cover 3 while being disposed oppositely to the sensor 100. The coil 4 is connected with a receiving unit 5 in the inner pressure detector through a lead wire 6. The unit 5 radiates electromagnetic wave through the coil 4 toward the sensor 100 and the inner pressure of tire is checked based on an echo signal received by the sensor 100.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire pressure sensor and a sensor housing used for the same, and more particularly to a tire pressure sensor for detecting a tire pressure while the vehicle is running.
The present invention relates to a tire air pressure detection sensor used in an internal pressure alarm device for notifying a tire air pressure abnormality, and a sensor housing used therefor.

[0002]

2. Description of the Related Art Generally, the inner pressure of the inside of a tire assembled with a rim and filled with air is extremely gradually decreased due to permeation or the like, so that air is replenished at any time. In recent years, a low internal pressure alarm device has been proposed that detects a decrease in the internal pressure of the tire and warns the driver. Low internal pressure alarm device
Attached to the rim of the vehicle, which detects the internal pressure of the tire and sends out a detection signal, and a tire air pressure detection sensor that is attached to the axle case or the vehicle body, which is the fixed side of the vehicle, to receive the detection signal and alert the driver It has an alarm unit.

An example of a conventional tire air pressure detection sensor for a low internal pressure alarm device is shown in FIG. The tire air pressure detection sensor 300 shown in FIG. 4 includes a cylindrical base end portion 303 inserted from the tire air chamber 2A into a rim opening portion 301 formed in a rim 302 for a tubeless tire, and one end of the base end portion. And a flange-shaped tip portion 304 that is integrally formed with the rim and that engages with the inner surface of the rim. Further, a screw 303A is cut at the base end,
The nut 305 is screwed into the screw 303A at the base end to seal the air in the rim by the tightening force of the nut. At this time, an O-ring (not shown) or the like is interposed between the tip portion 304 and the engaging surface of the rim 302 to enhance airtightness.

Further, in the tire air pressure detecting sensor 400 shown in FIG. 5, a female screw 401A is directly cut in the rim opening 401 of the rim 402, and the male screw 40 is inserted in the rim opening 401.
Base end portion 40 of the tire pressure detection sensor having 3A formed therein
3 was screwed in to fix the tire air pressure detection sensor 400 in an airtight manner. At this time as well, an O-ring (not shown) or the like is interposed between the tip portion 404 and the engaging surface of the rim 402 to further enhance airtightness.

[0005]

However, in the internal pressure alarm device equipped with the air pressure sensor having the above structure, it is necessary to directly thread the base end portion of the air pressure sensor, and therefore the diameter of the base end portion is equal to the screw thread. It became difficult to make the air pressure sensor compact. Further, there is no general-purpose nut that fits the diameter of the body portion of the tire air pressure detection sensor, so that a dedicated nut must be manufactured, which causes a cost increase. Further, in the fixing method in which the screw is directly cut into the rim opening, the number of steps for processing the rim is increased, which also causes a cost increase. Furthermore, in order to maintain the airtightness between the tire air pressure detection sensor and the rim by any of the above mounting methods, a seal such as an O-ring or packing is used.
This is also a factor of cost increase due to the need for a means for increasing the number of parts.

The present invention has been made to solve the above-mentioned problems of the prior art. It is compact, and when it is attached to the rim, the air pressure sensor body and the rim are threaded and a dedicated nut is used. Furthermore, it is an object of the present invention to provide an inexpensive tire air pressure detection sensor and a sensor housing used therefor, which can prevent an increase in cost due to the use of sealing means such as an O-ring and packing.

[0007]

In order to achieve the above object, the present invention is directed to a tire pressure detecting device for detecting an air pressure in a tire air chamber, which is mounted through a rim opening formed in a rim of a wheel. In the sensor, a sensor body having a pressure switch and an oscillator including an oscillation coil therein, and a sensor housing containing the sensor body,
The sensor housing is characterized by including a tubular portion formed of an elastic body and having a holding portion for holding the rim on an outer peripheral surface thereof, and a bottom portion closing one end of the tubular portion.

Further, the sensor housing used in the tire air pressure detection sensor of the present invention comprises a tubular portion formed of an elastic body and a bottom portion closing one end of the tubular portion, and the outer periphery of the tubular portion. The surface is provided with a holding portion for holding a rim to which the tire air pressure sensor is attached.

[0009]

According to the tire air pressure detecting sensor of the present invention and the sensor housing used therefor, the elastic sensor housing is inserted into the rim opening portion up to the holding portion, and then the sensor main body is fitted and mounted in the housing portion of the sensor housing. By doing so, the sensor is fixed to the rim. That is, since the elastic sensor housing has the function of hermetically sealing the gap between the rim opening and the sensor body and the function of fixing the sensor body to the rim, the mounting work to the rim is extremely easy, and , O-rings, sealing means such as packing are not required.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a diagram showing a mounted state of a tire air pressure detection sensor 100 according to an embodiment of the present invention. In the tire air pressure detection sensor 100, for example, a pressure detection means such as a mechanical pressure switch whose contacts are turned on and off before and after a set pressure, and an electric pressure switch whose resistance value changes depending on the pressure are provided inside the tire 1. It is attached to the rim 2 of the tire 1 so as to be arranged. An antenna coil 4 of the tire internal pressure detection device is attached to the vehicle body side brake cover 3 so as to face the tire air pressure detection sensor 100. The antenna coil 4 is electrically connected to a receiving unit 5 of the internal pressure detecting device via a lead wire 6. Then, the receiving unit 5 causes the antenna coil 4 to radiate an electromagnetic wave toward the tire air pressure detection sensor 100, receives the eco signal received by the tire air pressure detection sensor 100, and changes the frequency of the eco signal to detect the tire. Detects abnormal internal pressure.

FIG. 2 is a schematic vertical sectional view of the tire air pressure detection sensor 100 according to the embodiment of the present invention. As shown in FIG. 2, the tire air pressure detection sensor 100 of the present invention comprises a sensor body 101 and a sensor housing 102. The sensor body 101 has a base end portion 101A and a tip end portion 101B having an outer diameter larger than that of the base end portion. Are connected concentrically.

A pressure switch whose contacts are turned on and off by the air pressure of the tire is arranged inside the tip portion 101B, and a communication means for guiding the air of the tire to the pressure switch is formed at the tip portion 101B. . Further, an oscillator including an oscillation coil is arranged inside the base end portion 101A.

The sensor housing 102 has a cylindrical portion 102.
It has A and a bottom portion 102B, and is formed of rubber or a rubber-like elastic body, plastic having elasticity, or the like into an integrally formed substantially cylindrical shape. The bottom portion 102B does not have to be an elastic body, and may be, for example, hard plastic or the like. A storage space for the sensor body 101 is formed inside the tubular portion 102A. Further, a holding portion 103 for holding the rim is formed on the outer surface of the cylindrical portion 102A. The sandwiching portion 103 engages with a flange-shaped inner engagement protrusion 103A that engages with the rim surface inside the tire air chamber, and engages with the rim surface outside the tire air chamber, and from this inner engagement protrusion 103A in the axial direction of the sensor housing. , The outer engaging projections 103B, which are the same as the rim wall thickness in the rim opening or slightly spaced from the rim wall thickness. It should be noted that this outer engagement protrusion 103B is shown in FIG.
As shown in (3), the hemispherical shape facilitates insertion into the rim opening. In addition, the inner engagement protrusion 103A has a wedge shape in its cross section so that the gap between the inner engagement protrusion 103B and the outer engagement protrusion 103B becomes narrower toward the outer periphery of the inner engagement protrusion 103A. Due to this shape, the inner engagement protrusion 103
Even when the distance between A and the outer engagement protrusion 103B is made slightly smaller than the rim wall thickness in the rim opening, when the sensor housing is attached to the rim opening, the inner engagement protrusion 10
It is possible to prevent the tip of 3A from flipping up from the rim surface, and improve airtightness. Further, the inner surface of the cylindrical portion 102A of the sensor housing 102 has substantially the same shape as the outer shape of the sensor body 101, and is preferably formed to be slightly smaller than the outer dimension of the sensor body to securely hold the sensor body. I can do things. In addition, in the present embodiment, the sandwiching portion 103 is formed by the outer engaging projections 103B and 103A, but the tubular portion 1
A notch may be formed in a part of the outer peripheral surface of 02A, and both walls of the notch may be used as the holding portion 103.

FIG. 3 is a schematic sectional view showing the mounting of the tire air pressure detecting sensor according to the embodiment of the present invention on the wheel rim 2. In FIG. 3, 2A shows the inside of the tire air chamber, and 2B shows the outside of the tire air chamber. As shown in FIG.
The tire air pressure detection sensor 100 is provided on the vehicle body side.
It is attached to a rim opening opened on the rim 2 at a position facing the antenna coil attached to the cover. The sensor housing is attached to the rim of the sensor housing 1
Before mounting the sensor main body 101 on 02, first, the sensor housing is inserted from the tire air chamber inner side 2A to the bottom 102A into the rim opening, and the inner engagement protrusion 103 of the sensor housing is inserted.
Install so that the rim is sandwiched between A and the outer engagement protrusion 103B. By mounting the sensor housing in this way, one end of the storage space of the sensor body 101 is sealed by the bottom portion 102A, so that tire air will not leak from the storage space of the sensor body 101. Next, an adhesive is applied to the housing 103 of the sensor housing and the outer surfaces of the sensor body 101, and the sensor body is pushed into the housing and fixed. As a result, the sensor housing is pressed against the wall surface of the rim opening by the sensor body, and the rim opening is sealed.
Therefore, the sensor body can be airtightly fixed to the rim. As described above, since the screw tightening means is not used for mounting the tire air pressure detection sensor, there is no fear that the screw will be loosened or the tire air pressure detection sensor will fall off the rim, and the reliability of the device can be improved.

[0013]

The tire air pressure detection sensor of the present invention and the sensor housing used for the same have the above-described structure, so that the sensor can be easily attached and the number of parts such as a dedicated nut and O-ring can be reduced. Therefore, the cost of the device can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a tire internal pressure detection device including a tire air pressure detection sensor according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view of a tire air pressure detection sensor according to an embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view showing a state in which a tire air pressure detection sensor according to an embodiment of the present invention is attached to a rim.

FIG. 4 is a schematic side view showing a conventional tire air pressure detection sensor.

FIG. 5 is a schematic side view showing another example of a conventional tire air pressure detection sensor.

[Explanation of symbols]

 100 Tire Pressure Detection Sensor 101 Sensor Main Body 102 Sensor Housing 102A Cylindrical Part 102B Bottom Part 103 Clamping Part

Claims (2)

[Claims] 1. A tire air pressure sensor which penetrates a rim opening formed in a rim of a wheel and which detects air pressure in a tire air chamber, and has a pressure switch and an oscillator including an oscillation coil. A sensor main body and a sensor housing for accommodating the sensor main body, wherein the sensor housing is formed of an elastic body and has a tubular portion provided with a holding portion for holding the rim on an outer peripheral surface and one end of the tubular portion. A tire air pressure detection sensor, comprising a closed bottom portion. 2. A holding member having a tubular portion formed of an elastic body and a bottom portion closing one end of the tubular portion, and holding a rim for mounting a tire pressure sensor on an outer peripheral surface of the tubular portion. A sensor housing used for a tire pressure detection sensor, which is provided with a portion.