JP6892322B2 - Tire monitoring device and tires - Google Patents

Description

The present invention relates to a tire monitoring device provided with a functional component for detecting the state of the tire and a tire provided with the tire monitoring device.

Conventionally, a technique has been known in which a monitoring device provided with functional parts such as a sensor for detecting temperature, pressure, vibration, etc. in a tire is mounted in the tire to detect the state of the tire. As shown in Patent Document 1 and Patent Document 2, the monitoring device includes, for example, a substrate on which a plurality of sensors for detecting the state of a tire are arranged, and functional parts such as a battery that supplies electric power to each sensor. It is housed in one case, and the internal structure is protected by filling the space inside the case with a potting material filler, which is also called a sealing material or a filler.

JP-A-2015-157777 JP-A-2007-256143

However, when the rotational speed of the tire increases, as in high-speed driving, a large acceleration is applied to the monitoring device, so that force also acts on each of the built-in functional parts. For example, a functional component having a density higher than that of a commonly used potting material, such as a battery, exerts a large force on the potting material. As a result, the potting material is damaged such as cracks, the structure of the functional parts in the case cannot be maintained, and there is a risk of causing a failure of the monitoring device, which may affect the durability.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a monitoring device capable of improving durability.

As a configuration of a tire monitoring device for solving the above problems, a circuit board and a battery are housed in a case which is attached to the inner surface of the tire and constitutes a functional component for detecting the state of the tire, and the periphery of the circuit board and the battery. It is a monitoring device filled with a potting material so as to cover the above, and the potting material has an elastic modulus of 1 GPa or more and a tensile strength of 30 MPa or more.
According to this configuration, even when the tire rotates at high speed, the potting material can be prevented from being destroyed, and the resistance to the force received by the potting material from the functional parts can be ensured, so that the durability of the monitoring device can be improved. ..
Further, by using urethane resin or epoxy resin as the material of the potting material, it is possible to surely protect the internal structure of the functional component in the case.
Further, since the tire is provided with the tire monitoring device according to claim 1 or 2, the state of the tire can be stably acquired.

It is a figure which shows the attachment form of the monitoring device attached to a tire. It is sectional drawing which shows the structure of a monitoring apparatus. It is a table that summarizes the effects of changing the potting material.

Hereinafter, the present invention will be described in detail through embodiments of the invention, but the following embodiments do not limit the invention according to the claims, and all combinations of features described in the embodiments are the inventions. It is not always essential for the solution, but includes a configuration that is selectively adopted.

FIG. 1 is a diagram showing a mounting mode of a monitoring device 2 mounted on a tire T via a mounting pedestal 3. FIG. 2 is a cross-sectional view of the monitoring device 2 and the mounting pedestal 3. As shown in each figure, the monitoring device 2 is arranged on the inner peripheral surface Ts of the tire T via the mounting pedestal 3. The tire T is a so-called hollow pneumatic tire, and includes a bead core 11, a carcass 12, a belt layer 13, a chafer 14 mainly composed of a cord member, and a rubber member fleshed out on a skeleton composed of these members. The main body includes a bead filler 15, a chafer rubber 16, an inner liner 17, a sidewall rubber 18, and a tread rubber 19.

The bead core 11 is provided on each of the bead portions T2 on the inner diameter portion side of the side portions T1 on both sides of the tire T. A bead filler 15 is provided adjacent to the bead core 11 on the outer side in the radial direction. The carcass 12 is wound around the bead core 11 and the bead filler 15. The carcass 12 is composed of one or a plurality of carcass plies, and the extension direction of the carcass cord is oriented in the radial direction (radial direction) to form a toroidal shape in the tire T. The carcass 12 is folded back from the inside to the outside in the tire width direction so as to wrap the bead core 11 and the bead filler 15 at the left and right bead portions T2. Further, the bead portion T2 is provided with a chafer 14 and a chafer rubber 16. The chafer rubber 16 extends on the inner peripheral side so as to cover the carcass 12 so as to overlap the range of the bead core 11 and the bead filler 15. The chafer 14 extends so as to cover the bead core 11 and the bead filler 15 on the inner peripheral side and the bead core 11 on the outer peripheral side in the chafer rubber 16. An inner liner 17 is arranged between the left and right chafer rubbers 16; 16 on the inner peripheral side of the carcass 12. On the outer peripheral side of the carcass 12 in the side portion T1, a sidewall rubber 18 overlapping the outer peripheral side of the chafer rubber 16; 16 is arranged so as to extend toward the tread portion T3. A belt layer 13 in which a plurality of belt members are laminated is arranged on the outer peripheral side of the carcass 12 in the tread portion T3. A tread rubber 19 is arranged on the outer side of the belt layer 13 in the radial direction of the tire in succession with the left and right sidewall rubbers 18; 18. As shown in FIG. 1, the monitoring device 2 is attached to an inner liner 17 that forms a tire inner peripheral surface Ts at a central portion in the tire width direction via a mounting pedestal 3.

The monitoring device 2 includes a plurality of sensors for detecting the temperature, pressure, vibration, etc. of the circuit board 31 and the air chamber of the battery tire T, and a transmission circuit 38, a control circuit 40, and a detection value detected by each sensor. It also includes functional components such as a battery as a power source for operating the transmission circuit 38 and the control circuit 40. The plurality of sensors 32; 34; 36 and the transmitter that transmits the detection value detected by each sensor are mounted on the circuit board 31 and housed in the case 20 together with the battery.

As shown in FIG. 2A, the monitoring device 2 includes a circuit board 31 and a battery 46 inside the case 20. The case 20 is composed of, for example, a lower case 20A and an upper case 20B made of a synthetic resin or the like, and when the lower case 20A and the upper case 20B are combined, the diameter of the lower case 20A side is reduced to a flat disk type. It is formed so as to have an outer shape. The monitoring device 2 is accommodated in the mounting pedestal 3, which will be described later, with the mounting direction set to the mounting pedestal 3, for example, with the lower case 20A facing the tire inner peripheral surface Ts.

The upper and lower cases 20A; 20B are each formed in a container shape with one end open, and by combining with each other, one space S for accommodating the circuit board 31, the battery 46, and the like is formed. Although not shown, the surfaces of the lower case 20A and the upper case 20B forming the space S are provided with protrusions for positioning functional parts such as the circuit board 31 and the battery 46 at predetermined positions.

The circuit board 31 has a plurality of sensors for detecting the state of the tire T, such as a temperature sensor 32 for detecting the temperature in the air chamber of the tire T, a pressure sensor 34 for detecting the pressure, and an acceleration sensor 36 for detecting vibration and the like. A transmission circuit 38 that transmits the detection values detected by 32; 34; 36 and each sensor 32; 34; 36, and a control that controls transmission of the detection value detected by each sensor 32; 34; 36 from the transmission circuit 38. The circuit 40 and the like are mounted. The configuration of the circuit board 31 is an example and can be changed as appropriate.
The temperature sensor 32, the pressure sensor 34, and the acceleration sensor 36 are arranged on the same surface side of the circuit board 31, for example, and the transmission circuit 38 and the control circuit 40 functioning as transmitters are arranged on the other surface side. Further, on the other surface side of the circuit board 31, terminals 42A; 42B connected to the electrodes of the battery 46 are provided. When the monitoring device 2 is attached to the inner surface of the tire, the circuit board 31 is housed in the case 20 with one side facing the center of the tire (the other side facing the inner surface of the tire).

The temperature sensor 32 surrounds the measuring unit 32A and includes an introduction cylinder 32B for introducing the air in the tire into the measuring unit 32A, and the pressure sensor 34 surrounds the pressure sensitive surface 34A and air in the tire to the pressure sensitive surface 34A. Each of the introduction cylinders 34B for introducing the above is provided.
The introduction cylinder 32B of the temperature sensor 32 and the introduction cylinder 34B of the pressure sensor 34 extend in the direction perpendicular to the circuit board 31, respectively, and when the circuit board 31 is housed in a predetermined position in the case 20, the upper case 20B It is inserted into the through holes 22; 24 provided in. As a result, even when the circuit board 31 is housed in the case 20, the measuring unit 32A and the pressure sensitive surface 34A are exposed to the air in the tire, and the state in the tire air chamber is accurately measured. be able to.

For example, the transmission circuit 38 executes a predetermined program based on the acceleration sensor 36 detecting the rotation (centrifugal force) of the tire T, and the tire T detected by the temperature sensor 32, the pressure sensor 34, and the acceleration sensor 36. The temperature, pressure, and acceleration inside are transmitted to the outside of the tire by wireless communication. Signals such as temperature, pressure, and acceleration transmitted wirelessly from the transmission circuit 38 are received by the wireless circuit of the main body unit provided in the vehicle (not shown), and for example, the tire condition (for example, a display provided in the vehicle). Display information about temperature, pressure, or with or without anomalies).

The battery 46 is a so-called button battery, and is attached to the circuit board 31 by sandwiching it between the terminals 42A; 42B while bringing each electrode into contact with the metal terminals 42A; 42B extending from the circuit board 31. Although the battery 46 is shown as a button battery in the figure, the battery 46 is not limited to the button battery and may be a tubular battery, and the form thereof is not particularly limited. Then, the circuit board 31 is accommodated with the battery 46 attached toward the lower case 20A.

The inside of the case 20 is filled with the potting material 48 in a state where the circuit board 31 and the battery 46 are housed. That is, the entire circuit board 31 excluding the measuring unit 32A of the temperature sensor 32 and the pressure sensitive surface 34A of the pressure sensor 34 and the battery 46 are covered with the potting material 48.

As the potting material 48, a material having an elastic modulus after curing of 1000 MPa (1 × 10 GPa) or more and a material strength of 30 MPa or more is applied. The material strength referred to here is the strength measured by the tensile test. Further, as the material of the potting material 48, a urethane resin or an epoxy resin is preferable. By filling the inside of the case 20 with the potting material 48 having the above-mentioned mechanical characteristics, the force received by the potting material 48 from the battery 46 and the circuit board 31 even when the tire T is rotated, particularly at high speed. Sufficient resistance can be obtained.

For example, the potting material 48 is filled in the case 20 in a molten state from an injection hole 26 provided in the lower case 20A in a state where the circuit board 31, the battery 46, and the like are housed in the case 20. As a result, the entire circuit board 31 and the battery 46 except for the measuring unit 32A of the temperature sensor 32 and the pressure sensitive surface 34A of the pressure sensor 34 are covered with the molten potting material. The air in the case 20 is pushed out from the air vent hole 28 by the potting material 48 injected from the injection hole 26 and exhausted. After that, the injected potting material 48 is cured, so that the relative positions of the circuit board 31 and the battery 46 in the case 20 are positioned. The relative position means the position of the circuit board 31 and the battery 46 with respect to the case 20, or the position of the battery 46 with respect to the circuit board 31.

As shown in FIG. 2B, the mounting pedestal 3 has a sticking portion 30 having a sticking surface 30a to be stuck to the inner peripheral surface Ts of the tire, and rises upward from the sticking portion 30 to monitor the monitoring device 2. It has an accommodating wall portion 50 forming a substantially cylindrical accommodating portion 52 as an accommodating space capable of accommodating the tire. The mounting pedestal 3 is integrally formed of an elastic material (elastomer) such as natural rubber or synthetic rubber so as to follow the deformation of the tire T. The sticking portion 30 is a plate-shaped member formed in a circular cross section, and its lower surface is formed as a sticking surface 30a to be stuck in contact with the inner peripheral surface Ts of the tire. The sticking surface 30a is formed as a flat surface before sticking to the tire inner peripheral surface Ts. The accommodating portion 52 wraps around the case 20 and is formed following the outer shape of the case 20 so as to fit the outer shape of the case 20 exactly.

An annular accommodating wall portion 50 is provided on the upper surface of the sticking portion 30 so as to project upward. The accommodating wall portion 50 is a wall portion formed on a concentric circle centered on the central axis 3x of the circular pasting portion 30, and the accommodating portion 52 corresponding to the outer shape of the monitoring device 2 by the inner peripheral surface 54 thereof. Is formed. The accommodating wall portion 50 protrudes inward in the radial direction from the peripheral surface holding portion 50a in contact with the outer peripheral surface of the monitoring device 2 accommodated in the accommodating portion 52 and the tip of the peripheral surface holding portion 50a, and the upper surface 2c of the monitoring device 2 It has a top surface holding portion 50b that holds the peripheral edge portion of the above surface so as to push it down. The inner diameter portion of the top surface holding portion 50b is formed as an opening 56 that allows the monitoring device 2 to be accommodated in the accommodating portion 52, and the monitoring device 2 is accommodated by expanding the opening 56. The diameter of the inner peripheral surface 54 of the accommodating wall portion 50 is formed to be smaller than the diameter of the outer peripheral surface 2b of the monitoring device 2. When the monitoring device 2 is accommodated in the accommodating portion 52, the inner peripheral surface 54 is the monitoring device. It comes into close contact with the outer peripheral surface 2b of 2 and exerts a binding force.

In FIG. 3, a plurality of monitoring devices 2 filled with potting materials having different materials and characteristics are prepared, each monitoring device 2 is actually attached to a tire, and the monitoring device 2 is disassembled after traveling for 30 minutes on a drum tester. This is a table summarizing the results of visual inspection of the condition of the potting material and examination of the presence or absence of breakage. For the evaluation, passenger car tires having a tire size of 195 / 55R16 were used and attached to the inner liner surface on the back surface side of the tread center.

As shown in the table of the figure, when the elastic modulus of the potting material 48 is 1 GPa or more and the material strength is 30 Mpa or more, even if the tire rotation speed is 250 km / h or more, the epoxy-based and urethane-based materials are used. No abnormality was found regardless of the material.
On the other hand, when the elastic modulus of the potting material 48 was less than 1 GPa and the material strength was less than 30 MPa, fracture was observed regardless of the material.

From the above experimental results, by applying a material having an elastic modulus of 1 GPa or more and a material strength of 30 MPa or more to the potting material 48, even when the tire rotates at a high speed such as 250 km / h or more, the potting material can be used. Destruction can be prevented, resistance to the force received by the potting material from the functional parts can be ensured, and the durability of the monitoring device can be improved. Further, by applying a urethane resin or an epoxy resin to the material of the potting material, the internal structure of the functional component in the case can be reliably protected.

2 Monitoring device, 3 Mounting pedestal, 31 Circuit board, 30a Sticking surface,
52 housing, 48 potting material, T tire, Ts tire inner peripheral surface.

Claims (3)

A monitoring device in which a case containing a circuit board and a battery, which is attached to the inner surface of a tire and constitutes a functional component for detecting the state of the tire, is filled with a potting material so as to cover the periphery of the circuit board and the battery. ,
A tire monitoring device characterized in that the potting material has an elastic modulus of 1 GPa or more and a tensile strength of 30 MPa or more. The tire monitoring device according to claim 1, wherein the potting material is a urethane resin or an epoxy resin. A tire provided with the tire monitoring device according to claim 1 or 2.

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