阅读说明：本技术 充气轮胎 (Pneumatic tire ) 是由 成濑雅公 松田淳 干场崇史 于 2019-11-12 设计创作，主要内容包括：提供一种充气轮胎,该充气轮胎可使传感器单元的插入工作简单,可以防止传感器单元的脱落,并且可提高生产率。在轮胎内表面(Ts)具有用于容纳传感器单元(20)的至少一个橡胶制容纳体(10),传感器单元(20)包括用于获取轮胎信息的传感器(23),容纳体(10)具有插入传感器单元(20)的开口部(11)并相对于轮胎内表面(Ts)硫化粘合。(Provided is a pneumatic tire which can simplify the insertion work of a sensor unit, can prevent the sensor unit from falling off, and can improve the productivity. At least one rubber container (10) for containing a sensor unit (20) is provided on the inner surface (Ts) of the tire, the sensor unit (20) includes a sensor (23) for acquiring tire information, and the container (10) has an opening (11) into which the sensor unit (20) is inserted and is bonded by vulcanization to the inner surface (Ts) of the tire.)

1. A pneumatic tire characterized in that a tire tread is formed,

at least one rubber receiving body for receiving a sensor unit on the inner surface of the tire, the sensor unit comprising a sensor for acquiring tire information,

the housing body has an opening portion for inserting the sensor unit and is vulcanization bonded to the tire inner surface.

2. A pneumatic tire characterized in that a tire tread is formed,

at least one rubber receiving body for receiving a sensor unit on the inner surface of the tire, the sensor unit comprising a sensor for acquiring tire information,

the containing body includes: a rubber layer laminated on the inner surface of the tire and having an outer edge portion vulcanized and bonded to the inner surface of the tire; a receiving portion formed between the rubber layer and the tire inner surface; and an opening portion communicating with the accommodating portion.

3. A pneumatic tire characterized in that a tire tread is formed,

at least one rubber receiving body for receiving a sensor unit on the inner surface of the tire, the sensor unit comprising a sensor for acquiring tire information,

the containing body includes: a plate-like base portion joined with respect to the tire inner surface by means of a vulcanization adhesive; a cylindrical portion protruding from the base portion; an accommodating part formed in the cylinder part; and an opening portion communicating with the accommodating portion.

4. A pneumatic tire according to claim 3, wherein as the roughness of the inner surface of the tire in the fixing region of the receiving body, the arithmetic average height Sa ranges from 0.3 μm to 15.0 μm, and the maximum height Sz ranges from 2.5 μm to 60.0 μm.

5. A pneumatic tire according to any one of claims 1 to 4, wherein a relationship between the width Lc1 of the opening portion of the accommodating body and the inner width Lc2 of the bottom surface of the accommodating body satisfies Lc1< Lc 2.

6. A pneumatic tire according to any one of claims 1 to 5, wherein a relationship of 0.10 ≦ Lc1/Lsm ≦ 0.95 is satisfied between a width Lc1 of the opening portion of the housing and a maximum width Lsm of the sensor unit inserted into the housing.

7. A pneumatic tire according to any one of claims 1 to 6, wherein a relationship Lc1< Ls1 ≦ Ls2 ≦ Lc2 is satisfied between a width Lc1 of the opening portion in the housing and an inner width Lc2 of the bottom surface and a width Ls1 of the upper surface and a width Ls2 of the lower surface in the sensor unit inserted in the housing.

8. A pneumatic tyre according to any one of claims 1 to 7, characterized in that said containing body has an average thickness comprised between 0.5mm and 5.0 mm.

9. A pneumatic tire according to any one of claims 1 to 8, wherein a ratio of a height Hc of the housing in a state in which the sensor unit is inserted to a height Hs of the sensor unit inserted in the housing ranges from 0.5 to 1.5.

10. A pneumatic tire according to any one of claims 1 to 9, wherein the rubber forming the housing has an elongation at break EB of 50% to 900%, and the modulus at 300% elongation of the rubber forming the housing is 2MPa to 15 MPa.

11. A pneumatic tire according to any one of claims 1 to 10, wherein the housing body is provided at a position closer to the inner side in the tire width direction than the ground contact end.

Technical Field

The present invention relates to a pneumatic tire, and more particularly, to a pneumatic tire in which insertion work of a sensor unit is simple, and drop-out of the sensor unit can be prevented to improve productivity.

Background

A sensor unit including a sensor for acquiring tire internal information such as internal pressure and temperature is provided in a tire cavity (see, for example, patent documents 1 and 2). However, when a rubber-made housing body (container) for housing the sensor unit is mounted on the inner surface of the tire, an adhesive or a tape is generally used, but in order to improve the adhesion to the inner surface of the tire, primer treatment (undercoating treatment) needs to be performed in advance, which causes a problem of lowering productivity.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 6272225

Patent document 2: japanese Kokai publication 2016-505438

Disclosure of Invention

Problems to be solved by the invention

The present invention aims to provide a pneumatic tire which can simplify the insertion operation of a sensor unit, prevent the sensor unit from falling off, and improve the productivity.

Technical scheme

A pneumatic tire of the present invention for achieving the above object is characterized in that at least one rubber-made housing body for housing a sensor unit including a sensor for acquiring tire information is provided on a tire inner surface, the housing body has an opening portion inserted into the sensor unit, and is vulcanization-bonded to the tire inner surface.

Further, a pneumatic tire according to the present invention is a pneumatic tire having at least one rubber housing for housing a sensor unit including a sensor for acquiring tire information, on an inner surface of the tire, the housing including: a rubber layer laminated on the inner surface of the tire and having an outer edge portion vulcanized and bonded to the inner surface of the tire; a receiving portion formed between the rubber layer and the tire inner surface; and an opening portion communicating with the accommodating portion.

Further, a pneumatic tire according to the present invention is a pneumatic tire having at least one rubber housing for housing a sensor unit including a sensor for acquiring tire information, on an inner surface of the tire, the housing including: a plate-like base portion joined with respect to the tire inner surface by means of a vulcanization adhesive; a cylindrical portion protruding from the base portion; an accommodating part formed in the cylinder part; and an opening portion communicating with the accommodating portion.

Effects of the invention

In the present invention, at least one rubber-made housing body for housing a sensor unit including a sensor for acquiring tire information is provided on the inner surface of a tire, and the housing body has an opening portion for inserting the sensor unit, so that it is possible to make the work of inserting the sensor unit into the housing body easy, and to firmly hold the sensor unit and prevent the sensor unit from falling off by fastening the housing body. Further, since the container is vulcanization-bonded to the inner surface of the tire, a primer treatment required in the case of fixing the container using a tape or the like is not required, and productivity can be improved.

In the present invention, it is preferable that the arithmetic average height Sa is in the range of 0.3 μm to 15.0 μm and the maximum height Sz is in the range of 2.5 μm to 60.0 μm as the roughness of the inner surface of the tire in the fixing region of the accommodating body. Thereby, the adhesion area between the tire inner surface and the vulcanization adhesive can be increased, and the adhesion between the tire inner surface and the housing body can be effectively improved. The roughness of the inner surface of the tire is measured according to ISO 25178. The arithmetic average height Sa is an average of absolute values of height differences of points with respect to the average surface of the surface, and the maximum height Sz is a distance in the height direction from the highest point to the lowest point of the surface.

In the present invention, it is preferable that the relationship Lc1< Lc2 be satisfied between the width Lc1 of the opening portion of the accommodating body and the inner width Lc2 of the bottom surface of the accommodating body. Accordingly, the width Lc1 of the opening portion is relatively small, so that the sensor unit inserted into the accommodating body can be prevented from falling off, and operability in inserting the sensor unit and holding ability of the accommodating body can be both achieved.

In the present invention, it is preferable that the width Lc1 of the opening portion of the housing and the maximum width Lsm of the sensor unit inserted into the housing satisfy a relationship of 0.10 ≦ Lc1/Lsm ≦ 0.95. By appropriately setting the ratio of the width Lc1 of the opening portion to the maximum width Lsm of the sensor unit, the sensor unit can be effectively prevented from falling off, and the operability at the time of inserting the sensor unit and the retainability of the accommodating body can be improved.

In the present invention, it is preferable that the relationship Lc1< Ls1 ≦ Ls2 ≦ Lc2 is satisfied between the width Lc1 of the opening portion in the housing and the inner width Lc2 of the bottom surface, and the width Ls1 of the upper surface and the width Ls2 of the lower surface in the sensor unit inserted in the housing. By appropriately setting the respective widths of the accommodating body and the sensor unit, the falling-off of the sensor unit can be effectively prevented.

In the present invention, it is preferable that the average thickness of the containing body is 0.5mm to 5.0 mm. This improves the balance among workability in inserting the sensor unit, the holding property of the housing body, and the fracture resistance of the housing body.

In the present invention, it is preferable that a ratio of a height Hc of the receiving body in a state where the sensor unit is inserted to a height Hs of the sensor unit inserted into the receiving body is in a range of 0.5 to 1.5. Thus, the sensor unit can be effectively prevented from falling off.

In the present invention, it is preferable that the rubber forming the housing has an elongation at break EB of 50% to 900%, and the modulus at 300% elongation of the rubber forming the housing is 2MPa to 15 MPa. This improves the balance among workability in inserting the sensor unit, the holding property of the housing body, and the fracture resistance of the housing body. Further, the elongation at break and the modulus at 300% elongation of the rubber forming the container were measured in accordance with JIS-K6251.

In the present invention, it is preferable that the accommodating body is provided at a position further toward the inner side in the tire width direction than the ground contact end. Thus, in the case of a sensor that detects the amount of wear of the tread portion, the sensor inserted into the sensor unit of the housing can accurately acquire the tire information.

In the present invention, the ground contact end is an end position in the tire axial direction when the tire rim is assembled to a regular rim, is placed vertically on a plane in a state of being filled with a regular internal pressure, and is applied with a regular load. The "regular Rim" refers to a Rim specified for each tire in a specification system including a standard for the tire, for example, a standard Rim in JATMA, "Design Rim (Design Rim)" in TRA, or "Measuring Rim (Measuring Rim)" in ETRTO. The "normal internal PRESSURE" is an air PRESSURE specified for each TIRE in a specification system including standards for TIREs, and is the maximum air PRESSURE in JATMA, the maximum value in TRA as listed in "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES (TIRE LOAD LIMITS AT variable PRESSURES INFLATION PRESSURES)", and the maximum value in ETRTO "INFLATION PRESSURE (INFLATION PRESSURE)", but is 250kPa in the case where the TIRE is for a car. The "normal LOAD" is a LOAD specified for each TIRE in a specification system including a standard for the TIRE, and is a maximum LOAD CAPACITY in JATMA, a maximum value in TRA as shown in "TIRE LOAD limit AT VARIOUS COLD INFLATION PRESSURES (TIRE LOAD limit AT variable TIRE INFLATION pressure requirements)" and a LOAD CAPACITY (LOAD CAPACITY) in ETRTO, but is a LOAD corresponding to 80% of the LOAD when the TIRE is for a passenger car.

Drawings

Fig. 1 is a meridian cross-sectional view showing one example of a pneumatic tire constituted by an embodiment of the present invention.

Fig. 2 is a plan view showing the containing body mounted on the pneumatic tire of fig. 1.

Fig. 3 is a perspective sectional view illustrating a state in which a sensor unit is inserted into the receiving body of fig. 2.

Fig. 4 is a sectional view illustrating a state in which a sensor unit is inserted into the receiving body of fig. 2.

Fig. 5 is a meridian cross-sectional view showing a modification of the pneumatic tire according to the embodiment of the present invention.

Fig. 6 is a plan view showing the containing body mounted on the pneumatic tire of fig. 5.

Fig. 7 is a perspective sectional view illustrating a state in which a sensor unit is inserted into the receiving body of fig. 6.

Fig. 8 is a sectional view illustrating a state in which a sensor unit is inserted into the receiving body of fig. 6.

Detailed Description

Hereinafter, the structure of the present invention will be described in detail with reference to the drawings. Fig. 1 to 4 show a pneumatic tire according to an embodiment of the present invention. In fig. 2 and 4, arrow Tc represents the tire circumferential direction, and arrow Tw represents the tire width direction.

As shown in fig. 1, a pneumatic tire according to an embodiment of the present invention includes: a tread portion 1 extending in a tire circumferential direction and having a ring shape; a pair of side walls 2, 2 provided on both sides of the tread portion 1; a pair of bead portions 3, 3 are provided on the inner side of the sidewall portion 2 in the tire radial direction.

The carcass layer 4 is mounted between the pair of bead portions 3, 3. The carcass layer 4 includes a plurality of reinforcing cords extending in the tire radial direction, and is folded back from the inner side to the outer side of the tire around bead cores 5 provided in the respective bead portions 3. A bead filler 6 made of a rubber composition having a triangular cross section is provided on the outer periphery of the bead core 5. Further, an inner liner 9 is provided in a region between the pair of bead portions 3, 3 in the tire inner surface Ts. The inner liner 9 forms a tire inner surface Ts.

On the other hand, a plurality of belt layers 7 are embedded in the tread portion 1 on the outer circumferential side of the carcass layer 4. These belt layers 7 include a plurality of reinforcing cords inclined with respect to the tire circumferential direction, and the reinforcing cords are disposed so as to intersect between the layers. In the belt layer 7, the inclination angle of the reinforcing cords with respect to the tire circumferential direction is set within a range of, for example, 10 ° to 40 °. Steel wires are preferably used as the reinforcing cords of the belt layer 7. In order to improve high-speed durability, at least one belt cover layer 8 in which reinforcing cords are arranged at an angle of, for example, 5 ° or less with respect to the tire circumferential direction is provided on the outer circumferential side of the belt layer 7. As the reinforcing cord of the belt cover layer 8, an organic fiber wire such as nylon or aramid is preferably used.

Further, the above-described tire internal structure is a representative structural example showing a pneumatic tire, but is not limited thereto.

In the pneumatic tire described above, at least one rubber accommodating body 10 is fixed in a region of the tread portion 1 corresponding to the tire inner surface Ts. The housing 10 is used to house a sensor unit 20 for acquiring tire information. The housing body 10 has an opening 11 for inserting the sensor unit 20 and is vulcanization bonded to the tire inner surface Ts. Since the accommodating body 10 is made of rubber, the accommodating body 10 is preferably expanded and contracted when the sensor unit 20 is taken out of and put into the opening portion 11.

Examples of the material of the receiving body 10 may include Chloroprene Rubber (CR), butyl rubber (IIR), Natural Rubber (NR), acrylonitrile-butadiene copolymer rubber (NBR), Butadiene Rubber (BR), styrene-butadiene rubber (SBR), and the like, and one or a mixture of two or more may be used. Since these materials have excellent adhesion to the butyl rubber constituting the tire inner surface Ts, when the housing 10 is formed of the above materials, sufficient adhesion between the housing 10 and the tire inner surface Ts can be ensured.

As shown in fig. 2 to 4, the accommodating body 10A (10) has at least one rubber layer 12 laminated on the tire inner surface Ts. The outer edge portion 12a of the rubber layer 12 is vulcanized and adhered to the tire inner surface Ts. A housing portion 13 for housing the sensor unit 20 is formed between the rubber layer 12 and the tire inner surface Ts, and the housing portion 13 communicates with the circular opening 11. The housing portion 13 has a circular planar shape concentric with the opening 11. In this manner, the housing portion 13 has a substantially trapezoidal cross-sectional shape with the tire inner surface Ts as a bottom surface and the opening 11 as an upper surface. A cylindrical sensor unit 20 having a tapered upper surface is accommodated in the accommodating portion 13.

In the embodiment of fig. 1 to 4, an example in which the containing body 10A is formed of one rubber layer 12 is shown, but the containing body 10A may be formed of a plurality of rubber layers 12. In this case, it is preferable that the rubber layer 12 closer to the tire inner surface Ts has a longer length in the tire circumferential direction and the tire width direction, and forms the housing 10A in a step shape. As such, when the rubber layer 12 is formed of a plurality of layers, the rubber layer 12 may include a layer whose entire surface is vulcanization-bonded to the tire inner surface Ts. In the embodiment of fig. 1 to 4, the opening 11 and the housing 13 are each illustrated as having a circular planar shape, but the shape is not particularly limited and may be appropriately changed according to the shape of the sensor unit 20 inserted into the housing 10A. For example, when the shape of the sensor unit 20 is a rectangular parallelepiped or a cube, the planar shapes of the opening portion 11 and the housing portion 13 may be set to be substantially quadrangular accordingly. Further, although an example in which the rubber layer 12 (outer edge portion 12a) has a quadrangular planar shape is shown, the planar shape of the rubber layer 12 (outer edge portion 12a) may be circular or another polygonal shape without particular limitation.

When manufacturing a pneumatic tire having the receiving body 10A on the tire inner surface Ts, in the molding process of the green tire, the rubber layer 12 is laminated on the inner liner 9 located on the innermost surface of the tire, and by vulcanizing the green tire on a vulcanizing machine, the receiving body 10A joined to the tire inner surface Ts in an integrated manner can be formed. For example, when the rubber layer 12 is laminated on the inner liner layer 9 (tire inner surface Ts), a green tire is vulcanized with a non-adhesive member (hereinafter referred to as a non-adhesive member) which is not adhered to the rubber composition interposed between the tire inner surface Ts and the rubber layer 12 and has a length shorter than that of the rubber layer 12 in the tire circumferential direction and the tire width direction, whereby the housing 10A integrally joined to the tire inner surface Ts can be formed. After the green tire is vulcanized, the non-adhesive member does not necessarily need to be removed, but by removing the non-adhesive member, the accommodating body 10A is in a state where the sensor unit 20 can be inserted. Also, the opening portion 11 may be formed by using a non-adhesive member having a convex portion corresponding to the opening portion 11, or may be formed by opening a hole in the rubber layer 12 of the pneumatic tire that is completed with vulcanization.

As shown in fig. 4, the sensor unit 20 includes a housing 21 and electronic components 22. The housing 21 has a hollow structure, and accommodates the electronic component 22 therein. The electronic components 22 are formed to appropriately include a sensor 23 for acquiring tire information, a transmitter, a receiver, a control circuit, a battery, and the like. The tire information acquired by the sensor 23 may be, for example, the internal temperature and internal pressure of the pneumatic tire, and the amount of wear of the tread portion 1. For example, a temperature sensor or a pressure sensor is used for measuring the internal temperature or the internal pressure. When detecting the wear amount of the tread portion 1, as the sensor 23, a piezoelectric sensor that abuts on the tire inner surface Ts and detects an output voltage according to tire deformation at the time of traveling, and the wear amount of the tread portion 1 can be detected based on the output voltage. Further, an acceleration sensor or a magnetic sensor may also be used. Also, the sensor unit 20 is formed to transmit the tire information acquired by the sensor 23 to the outside of the tire. In order to facilitate gripping of the sensor unit 20, a knob portion 24 (not shown) protruding from the housing 21 may be provided, and the knob portion 24 may be provided with an antenna function. The internal structure of the sensor unit 20 shown in fig. 4 is an example of the sensor unit, but is not limited thereto.

In the pneumatic tire described above, at least one rubber-made accommodating body 10A (10) accommodating the sensor unit 20 is provided in the tire inner surface Ts, the accommodating body 10A including: a rubber layer 12 laminated on the tire inner surface Ts, and having an outer edge portion 12a vulcanized and bonded to the tire inner surface Ts; a receiving portion 13 formed between the rubber layer 12 and the tire inner surface Ts; and an opening portion 11 communicating with the accommodating portion 13, so that work when inserting the sensor unit 20 into the accommodating body 10A is easy, and the sensor unit 20 can be firmly held by fastening the accommodating body 10A to prevent the falling-off of the sensor unit 20. Further, since the housing body 10A is vulcanization-bonded to the tire inner surface Ts, a primer treatment required in the case of fixing the housing body using a tape or the like is not required, and productivity can be improved.

Fig. 5 is a diagram showing a modification of the pneumatic tire according to the embodiment of the present invention. As shown in fig. 5, the containing body 10B (10) is engaged with the tire inner surface Ts by the vulcanization adhesive 14. As shown in fig. 6 to 8, the housing 10B includes a plate-shaped base portion 15 joined to the tire inner surface Ts, a cylindrical tube portion 16 protruding from the base portion 15, and a housing portion 17 formed in the tube portion 16. The housing portion 17 communicates with the circular opening portion 11. Such a housing portion 17 has a substantially rectangular cross-sectional shape with the base portion 15 as a bottom surface and the opening portion 11 as an upper surface. The accommodating portion 17 accommodates therein a cylindrical sensor unit 20 having a tapered upper surface. The shapes of the base portion 15, the cylindrical portion 16, and the housing portion 17 are not particularly limited, and may be appropriately changed according to the shape of the sensor unit 20 inserted into the housing body 10B.

The vulcanization adhesive 14 is not particularly limited, and a vulcanization adhesive capable of bonding a rubber composition may be used. Examples thereof include naturally vulcanized (curable at normal temperature) adhesives and puncture repair agents for emergency treatment during puncture of pneumatic tires.

When manufacturing a pneumatic tire having the containing body 10B on the tire inner surface Ts, after subjecting the pneumatic tire having completed vulcanization to any treatment such as cutting processing (so-called buffing), laser treatment, plasma treatment, or the like, the vulcanization adhesive 14 is applied on the tire inner surface Ts subjected to the above treatment, and the containing body 10B is disposed on the vulcanization adhesive 14. The above treatment is different from the primer treatment, and the treatment time is shorter than that of the primer treatment.

In the pneumatic tire described above, the tire inner surface Ts has at least one rubber-made accommodating body 10B (10) accommodating the sensor unit 20, the accommodating body 10B including: a plate-like base 15 joined with respect to the tire inner surface Ts by a vulcanization adhesive 14; a cylindrical portion 16 protruding from the base portion 15; an accommodating portion 17 formed in the cylindrical portion 16; and an opening portion 11 communicating with the housing portion 17, so that work when inserting the sensor unit 20 into the housing body 10B is easy, and the sensor unit 20 is firmly held by fastening the housing body 10B to prevent the sensor unit 20 from falling off. Further, since the housing body 10B is vulcanization-bonded to the tire inner surface Ts, a primer treatment required in the case of fixing the housing body using an adhesive tape or the like is not required, and productivity can be improved.

In the above pneumatic tire, it is preferable that, as the roughness of the tire inner surface Ts in the fixing region of the accommodating body 10B, the arithmetic average height Sa is in the range of 0.3 μm to 15.0 μm, and the maximum height Sz is in the range of 2.5 μm to 60.0 μm. As such, by appropriately setting the arithmetic average height Sa and the maximum height Sz as the roughness of the tire inner surface Ts, the adhesion area between the tire inner surface Ts and the vulcanization adhesive 14 can be made large, and the adhesion between the tire inner surface Ts and the accommodating body 10B can be effectively improved. When the arithmetic average height Sa exceeds 15.0 μm and the maximum height Sz exceeds 60.0 μm, the vulcanized adhesive 14 cannot follow the unevenness of the tire inner surface Ts, and the adhesiveness tends to deteriorate. The arithmetic average height Sa and the maximum height Sz are values measured in accordance with ISO25178, and can be measured using a commercially available surface texture measuring instrument (e.g., a shape analysis laser microscope, a 3D shape measuring instrument). The measurement method may be either of a contact type and a noncontact type.

In fig. 1 and 5, the accommodating bodies 10A and 10B (10) are provided at positions inward in the tire width direction from the ground contact ends. In the case of the sensor 23 that detects the amount of wear of the tread portion 1, the sensor 23 inserted into the sensor unit 20 in the accommodating body 10 can accurately acquire the tire information.

In the pneumatic tire described above, the accommodating body 10 may be set to the following dimensions. Preferably, the relationship Lc1< Lc2 is satisfied between the width Lc1 of the opening portion 11 of the accommodating body 10 and the inner width Lc2 of the bottom surface of the accommodating body 10. In this manner, by making the width Lc1 of the opening 11 narrower than the inner width Lc2 of the bottom surface of the accommodating body 10, the binding force on the upper surface side of the accommodating body 10 becomes stronger, and the sensor unit 20 inserted into the accommodating body 10 can be effectively prevented from falling off. This makes it possible to achieve both operability when inserting the sensor unit 20 and retention of the accommodating body 10. Further, the width Lc1 of the opening portion 11 in the accommodating body 10 and the inner width Lc2 of the bottom surface are both widths measured in a state where the sensor unit 20 is not inserted into the accommodating body 10.

And, it is preferable that the average thickness of the receiving body 10 is 0.5mm to 5.0 mm. As described above, by appropriately setting the average thickness of the accommodating body 10, the balance among the operability at the time of inserting the sensor unit 20, the retainability of the accommodating body 10, and the fracture resistance of the accommodating body 10 can be improved. However, if the average thickness of the housing 10 is smaller than 0.5mm, the housing 10 is easily broken when the sensor unit 20 is inserted, and if the average thickness of the housing 10 is larger than 5.0mm, the housing 10 has too much rigidity to easily insert the sensor unit 20. Further, the average thickness of the containing body 10 is a value in which the thickness of the rubber forming the containing body 10 is measured. When the containing body 10A is formed of a plurality of rubber layers 12, the total thickness of these rubber layers 12 is measured.

In particular, it is preferable that the following dimensions are satisfied between the receiving body 10 and the sensor unit 20. Preferably, the relationship of 0.10 ≦ Lc1/Lsm ≦ 0.95 is satisfied between the width Lc1 of the opening portion 11 of the accommodating body 10 and the maximum width Lsm of the sensor unit 20 inserted into the accommodating body 10, more preferably, the relationship of 0.15 ≦ Lc1/Lsm ≦ 0.80 is satisfied, and most preferably, the relationship of 0.15 ≦ Lc1/Lsm ≦ 0.65 is satisfied. As described above, by appropriately setting the ratio of the width Lc1 of the opening portion 11 of the accommodating body 10 to the maximum width Lsm of the sensor unit 20, the sensor unit 20 can be effectively prevented from falling off, and the operability at the time of inserting the sensor unit 20 and the retainability of the accommodating body 10 can be improved. In the sensor cell 20 of fig. 4 and 8, the maximum width Lsm corresponds to the width Ls2 of the lower surface.

Further, it is preferable that the width Lc1 of the opening 11 and the inner width Lc2 of the bottom surface in the housing 10 and the width Ls1 of the upper surface and the width Ls2 of the lower surface in the sensor unit 20 inserted into the housing 10 satisfy a relationship Lc1< Ls1 ≦ Ls2 ≦ Lc 2. Also, more preferably, the upper surface of the sensor cell 20 is tapered and satisfies the relationship Ls1< Ls 2. In this manner, by appropriately setting the widths of the accommodating body 10 and the sensor unit 20, the sensor unit 20 can be effectively prevented from falling off.

Also, it is preferable that the ratio of the height Hc of the receiving body 10 in the state where the sensor unit 20 is inserted to the height (maximum height) Hs of the sensor unit 20 inserted into the receiving body 10 is in the range of 0.5 to 1.5, more preferably in the range of 0.6 to 1.3, and most preferably in the range of 0.7 to 1.0. In this manner, by appropriately setting the ratio of the height Hc of the accommodating body 10 to the height Hs of the sensor unit 20, the sensor unit 20 can be effectively prevented from falling off. In the case where the knob portion 24 is provided in the sensor unit 20, the height Hs of the sensor unit 20 is a height including the knob portion 24 (see fig. 8). In the case of the accommodating body 10A, the height Hc is a height between the tire inner surface Ts and an end portion adjacent to the tire inner surface Ts and located on the outer side in the tire radial direction of the rubber layer 12 (see fig. 4). On the other hand, in the case of the accommodating body 10B, the height Hc thereof does not include the height of the base portion 15, but the height of the cylindrical portion 16 (see fig. 8).

In the pneumatic tire described above, the rubber forming the accommodating body 10 may have the following physical properties. Preferably, the elongation at break EB is 50% to 900%, the modulus at 300% elongation (M300) is 2MPa to 15 MPa. By setting the elongation at break EB and the modulus (M300) appropriately in this manner, the balance of the workability when inserting the sensor unit 20, the holding property of the housing 10, and the fracture resistance of the housing 10 can be improved.

Examples

Tires of examples 1 to 7 were manufactured, the tire size was 275/40R21, at least one rubber container for accommodating a sensor unit including a sensor for acquiring tire information was provided on the inner surface of the tire, and the structure of the container, the adhesion structure of the container to the inner surface of the tire, the ratio of the width Lc1 of the opening portion to the maximum width Lsm of the sensor unit (Lc1/Lsm) were set as shown in table 1.

For comparison, a tire of a conventional example in which no receiving body is provided on the inner surface of the tire was prepared. Further, the accommodating body having the structure of fig. 8 was provided in the inner surface of the tire, but primer treatment was performed before the accommodating body was fixed to the inner surface of the tire to prepare tires of comparative examples 1 to 3 different from the adhesive structure of examples 1 to 7. Specifically, the housing body of the tire of comparative example 1 was fixed by a double-sided tape, the housing body of the tire of comparative example 2 was fixed by an instant adhesive, and the housing body of the tire of comparative example 3 was fixed by a reaction curing type adhesive.

The productivity, workability when inserting the sensor unit, and durability of these test tires were evaluated by the following test methods, and the results are shown in table 1.

Productivity:

the time required for the manufacturing process including molding, vulcanization, installation of the housing, and inspection was measured for each test tire. The evaluation results are expressed as an index with the conventional example as 100. The smaller the index value means the more excellent the productivity. In addition, the required time does not include the time required to insert the sensor unit into the receiving body provided on the inner surface of the tire.

Operability when inserting the sensor unit:

for each test tire other than the tire of the conventional example, the time required for the work of inserting the sensor unit into the housing provided on the inner surface of the tire was measured. The evaluation results were expressed by using the reciprocal of the measurement value as an index with comparative example 1 as 100. The larger the index value means the easier the insertion work of the sensor unit.

Durability:

each test tire was mounted on a wheel having a rim size of 21 × 9.5J, and after a running test was performed using a drum tester under conditions of an air pressure of 120kPa, a running speed of 102% of a maximum load, 81km, and a running distance of 10000km, breakage of the housing body or detachment of the sensor unit was visually confirmed. The evaluation result indicates whether or not the housing body is broken and whether or not the sensor unit is detached.

As judged in Table 1, the pneumatic tires of examples 1 to 7 maintained productivity as compared with the conventional example. The pneumatic tires of examples 3 to 7 had improved operability when the sensor unit was inserted, compared to comparative example 1. The pneumatic tires of examples 3 to 6 were free from breakage of the housing body and dropping of the sensor unit.

On the other hand, in comparative examples 1 to 3, since the primer treatment was performed before the housing body was fixed to the inner surface of the tire, the productivity was lowered.

Description of the reference numerals

1 tread part

2 side wall part

3 bead portion

10 containing body

11 opening part

12 rubber layer

13 accommodating part

14-vulcanizing adhesive

15 base part

16 barrel part

17 accommodating part

20 sensor unit

Ts inner surface of tire

CL tire centerline.