Tire information sensing device

Abstract

The present invention provides a tire information sensing device that can determine the installation state of a sensor module provided in a pneumatic tire based on a measurement value supplied from the sensor module and accurately sense tire information. The tire information sensing device (10) that senses tire information including at least one of tire wear, tire deformation, road surface condition, tire contact state, presence or absence of tire failure, tire driving history, and tire load condition comprises: at least one sensor module (20) disposed on the inner surface of the tire; and a determination unit (15) that determines the installation state of the sensor module (20) based on the measurement value supplied from the sensor module (20).

Description

Technical Field

[0001] The present invention relates to a tire information sensing device, and more particularly to a tire information sensing device capable of accurately sensing tire information by determining the installation state of a sensor module provided in a pneumatic tire based on measurement values ​​supplied from the sensor module. Background Art

[0002] In pneumatic tires, for example, acceleration sensors are installed inside the tire to measure acceleration, and tire information (the wear condition of the tread) is evaluated based on these measured values ​​(see, for example, Patent Document 1). Therefore, when installing the sensor inside the tire, it is necessary to confirm whether the sensor is correctly positioned relative to the tire and whether it is functioning properly. However, the sensor's installation status is not determined based on the measured values.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2009-18667 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] An object of the present invention is to provide a tire information sensing device that can accurately sense tire information by determining the mounting state of a sensor module provided in a pneumatic tire based on measurement values ​​supplied from the sensor module.

[0008] Solutions for solving technical problems

[0009] The tire information sensing device of the present invention for achieving the above-mentioned purpose senses tire information including at least one of tire wear, tire deformation, road surface condition, tire contact condition, presence or absence of tire failure, tire driving history, and tire load condition. The tire information sensing device is characterized in that it comprises: at least one sensor module arranged on the inner surface of the tire; and a judgment unit that judges the installation status of the sensor module based on the measurement value supplied from the sensor module.

[0010] Effects of the Invention

[0011] In the present invention, there are: at least one sensor module, which is arranged on the inner surface of the tire; and a determination unit, which determines the installation status of the sensor module based on the measurement value supplied from the sensor module. Therefore, the measurement value supplied from the sensor module can be used to determine the installation status of the sensor module, and further, tire information can be sensed when the sensor module is functioning normally.

[0012] The tire information sensing device of the present invention preferably includes: an element mounted on a sensor module and generating a voltage based on deformation of the tire's tread during rotation; a voltage detection unit that detects the voltage generated by the element; a storage area that stores waveform data of the voltage detected by the voltage detection unit over time; and a calculation unit that calculates the symmetry of the waveform data, which serves as an indicator of the sensor module's mounting state, based on the waveform data stored in the storage area, wherein the determination unit determines the sensor module's mounting state based on the symmetry of the waveform data calculated by the calculation unit. The voltage generated by the element based on deformation of the tire's tread during rotation is preferably low in noise, can be measured and analyzed, and serves as an effective indicator for determining the sensor module's mounting state.

[0013] Preferably, the calculation unit extracts a waveform including a first peak point and a second peak point formed on either side of a baseline of the waveform data, calculates line segments SO and OF based on an intersection point O where a line connecting the first peak point and the second peak point intersects the baseline of the waveform data, a start point S of the waveform, and an end point F of the waveform. If the ratio of short segments to long segments in line segments SO and OF is between 0.4 and 1.0, the determination unit determines that the sensor module is in a good state of installation. This improves the accuracy of determining the sensor module's installation state.

[0014] Preferably, the calculation unit extracts a waveform including a first peak point and a second peak point formed on both sides of a baseline of the waveform data, calculates an absolute value of the difference |P1-B| between a value P1 of the first peak point and a value B of the baseline of the waveform data, and an absolute value of the difference |B-P2| between a value B of the baseline of the waveform data and a value P2 of the second peak point. If the ratio |P1-B| / |B-P2| of the absolute value of the difference |P1-B| to the absolute value of the difference |B-P2| is between 0.2 and 5.0, the determination unit determines that the sensor module is in a good state of installation. This improves the accuracy of determining the sensor module's installation state.

[0015] Preferably, the calculation unit extracts a waveform including a first peak point and a second peak point formed on either side of a baseline of the waveform data, calculates areas A1 and A2 of the waveform on either side of an intersection point O where a line connecting the first peak point and the second peak point intersects the baseline of the waveform data, and a waveform center axis passing through the intersection point O and perpendicular to the baseline of the waveform data. If the ratio of the smaller area to the larger area of ​​area A1 and area A2 is between 0.4 and 1.0, the determination unit determines that the sensor module is in a good state of installation. This improves the accuracy of determining the sensor module's installation state.

[0016] Preferably, the calculation unit calculates a voltage change index value based on the waveform data stored in the storage area, and the determination unit compares the voltage change index value calculated by the calculation unit with reference information to determine the progress of tread wear. This allows the sensor module's installation status to be determined, and the progress of tread wear to be accurately sensed.

[0017] Preferably, the tire information sensing device of the present invention includes a speed detection unit for detecting vehicle speed or tire rotational speed, a storage area for storing temporal waveform data of a voltage detected by the voltage detection unit together with the vehicle speed or tire rotational speed detected by the speed detection unit, a calculation unit for calculating a voltage variation index value based on the waveform data within a predetermined speed range stored in the storage area, and a determination unit for comparing the voltage variation index value calculated by the calculation unit with reference information corresponding to the predetermined speed range to determine the progress of tread wear. This allows the sensor module's installation status to be determined, allowing accurate sensing of the progress of tread wear.

[0018] Preferably, the calculation unit calculates the peak amplitude value between the maximum value P1 and the minimum value P2 in the waveform data as the voltage change index value. This can improve the accuracy of determining the progress of wear of the tread portion.

[0019] Preferably, the tire information sensing device of the present invention includes a speed detection unit for detecting vehicle speed or tire rotational speed, a storage area for storing temporal waveform data of a voltage detected by the voltage detection unit together with the vehicle speed or tire rotational speed detected by the speed detection unit, a calculation unit for calculating a frequency exceeding a predetermined threshold value based on the waveform data within a predetermined speed range and a predetermined time period stored in the storage area, and a determination unit for determining the progression of tread wear based on the frequency exceeding the predetermined threshold value calculated by the calculation unit. Thus, the progression of tread wear can be accurately detected.

[0020] Preferably, the tire information sensing device of the present invention includes an air pressure detection unit for detecting the air pressure inside the tire, and the calculation unit corrects waveform data or a predetermined threshold value based on the air pressure detected by the air pressure detection unit. This improves the accuracy of determining the progression of tread wear.

[0021] Preferably, the determination unit performs at least two determination operations and finally determines the progress of tread wear based on the results of these determination operations. This can suppress the occurrence of sudden errors in the final determination result and improve the accuracy of determining the progress of tread wear.

[0022] The sensor module includes at least an element and a voltage detection unit. The sensor module is preferably fixed to the inner surface of the tire via a container into which the sensor module is inserted.

[0023] Preferably, the housing is joined to the inner surface of the tire through an adhesive layer. As the roughness of the inner surface of the tire, the arithmetic mean 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. Thereby, the adhesion area between the inner surface of the tire and the adhesive layer can be increased, and the adhesion between the inner surface of the tire and the housing can be effectively improved. The roughness of the inner surface of the tire is a value measured in accordance with ISO25178. The arithmetic mean height Sa is the average of the absolute values of the differences in height of each point on the surface relative to the average surface, and the maximum height Sz is the distance in the height direction from the highest point to the lowest point on the surface.

[0024] Preferably, the width Lc1 of the opening of the housing and the inner width Lc2 of the bottom surface of the housing satisfy the relationship Lc1 < Lc2. Thereby, the width Lc1 of the opening is relatively small, so that the sensor module accommodated in the housing can be prevented from falling off, and the workability when inserting the sensor module and the holding property of the housing can be taken into account.

[0025] Preferably, the width Lc1 of the opening of the housing and the maximum width Lsm of the sensor module satisfy the relationship 0.10 ≤ Lc1 / Lsm ≤ 0.95. By appropriately setting the ratio of the width Lc1 of the opening to the maximum width Lsm of the sensor module, the sensor module can be effectively prevented from falling off, and the workability when inserting the sensor module and the holding property of the housing can be improved.

[0026] Preferably, the width Lc1 of the opening of the housing, the inner width Lc2 of the bottom surface of the housing, the width Ls1 of the upper surface of the sensor module, and the width Ls2 of the lower surface of the sensor module satisfy the relationship Lc1 < Ls1 ≤ Ls2 ≤ Lc2. By appropriately setting the respective widths of the housing and the sensor module, the sensor module can be effectively prevented from falling off.

[0027] Preferably, the average thickness of the housing is 0.5 mm to 5.0 mm. Thereby, the workability when inserting the sensor module, the holding property of the housing, and the fracture resistance of the housing can be improved with good balance.

[0028] Preferably, the ratio of the height Hc of the housing in the state where the sensor module is inserted to the height Hs of the sensor module is in the range of 0.5 to 1.5. Thereby, the sensor module can be effectively prevented from falling off.

[0029] The elongation at break (EB) of the rubber constituting the housing is preferably between 50% and 900%, and the modulus at 300% elongation is preferably between 2 MPa and 15 MPa. This achieves a well-balanced improvement in workability during sensor module insertion, housing retention, and fracture resistance. The elongation at break and modulus at 300% elongation of the rubber constituting the housing are values ​​measured in accordance with JIS-K6251.

[0030] Preferably, the housing is disposed on the inner side of the ground contact end in the tire width direction.

[0031] Preferably, the element is a piezoelectric element. A piezoelectric element generates voltage based on deformation of the tread portion during tire rotation. Therefore, compared to acceleration sensors and the like, noise is less likely to enter, enabling precise sensing.

[0032] In the present invention, the ground contact end refers to the axial end of the tire when the tire is placed vertically on a plane with the rim assembled on a regular rim and filled to the regular internal pressure, and a regular load is applied. A "regular rim" refers to the rim specified for each tire in the specification system to which the tire is based. For example, in the case of JATMA, it is the standard rim; in the case of TRA, it is the "Design Rim"; and in the case of ETRTO, it is the "Measuring Rim." "Regular internal pressure" refers to the air pressure specified for each tire in the specification system to which the tire is based. In the case of JATMA, it is the maximum air pressure; in the case of TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLDINFLATION PRESSURES"; in the case of ETRTO, it is the "INFLATION PRESSURE." However, in the case of a passenger car tire, it is 250 kPa. "Normal load" refers to the load specified for each tire in each specification in the specification system to which the tire is based. If it is JATMA, it is the maximum load capacity. If it is TRA, it is the maximum value recorded in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES". If it is ETRTO, it is "LOADCAPACITY". However, in the case of tires for passenger cars, it is set to a load equivalent to 80% of the above load. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1This is an explanatory diagram showing an example of a tire information sensing device according to an embodiment of the present invention.

[0034] Figure 2 This is a graph showing an example of waveform data stored in a storage area of ​​the tire information sensing device according to the embodiment of the present invention.

[0035] Figure 3 This is a graph showing another example of waveform data stored in the storage area of ​​the tire information sensing device according to the embodiment of the present invention.

[0036] Figure 4 This is a flowchart showing an example of the procedure of a sensing method using the tire information sensing device according to the embodiment of the present invention.

[0037] Figure 5 (a) Figure 5 (b) are Figure 3 An illustration of the waveform data.

[0038] Figure 6 This is a graph showing another example of waveform data stored in the storage area of ​​the tire information sensing device according to the embodiment of the present invention.

[0039] Figure 7 yes Figure 6 A graph showing waveform data after masking processing implemented by the calculation unit.

[0040] Figure 8 This is a flowchart showing a modified example of the procedure of the sensing method using the tire information sensing device according to the embodiment of the present invention.

[0041] Figure 9 This is a meridian cross-sectional view of a pneumatic tire showing the wear state determined by the tire information sensing device according to the embodiment of the present invention.

[0042] Figure 10 Is installed on Figure 9 A top view of a container for a pneumatic tire.

[0043] Figure 11 It means in Figure 9 A three-dimensional sectional view of a state where a sensor module is inserted into a housing.

[0044] Figure 12 It means in Figure 9 A cross-sectional view of a state where a sensor module is inserted into a housing.

[0045] Figure 13 This is a graph showing waveform data at multiple time points in the pneumatic tire of Example 1. DETAILED DESCRIPTION

[0046] Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. Figure 1 It is a diagram showing a tire information sensing device according to an embodiment of the present invention.

[0047] The tire information sensing device 10 senses the tire T (for example, Figure 9 ), the tire information sensing device 10 determines whether the installation state of the sensor module 20 is good based on the measurement value supplied from the sensor module 20. Furthermore, the tire information sensing device 10 senses the tire information of the tire T based on the measurement value supplied from the sensor module 20.

[0048] Tire information is a group consisting of tire wear, tire deformation, road surface conditions, tire contact state, tire fault status, tire driving history, and tire load status. At least one piece of tire information can be selected from this group and used as tire information. Tire information is not limited to the aforementioned group; additional information may be added as appropriate. The following describes a tire information sensing device 10 that senses tire T wear (the progression of wear on the tread portion 1) as tire information.

[0049] like Figure 1 As shown, the tire information sensing device 10 includes: an element 11, which is mounted on a sensor module 20 and generates a voltage based on the deformation of the tread portion 1 during tire rotation; a voltage detection unit 12, which detects the voltage generated by the element 11; a storage area 13, which stores waveform data of the voltage detected by the voltage detection unit 12 over time; a calculation unit 14, which calculates the symmetry of the waveform data as an indicator value of the installation state of the sensor module 20 based on the waveform data stored in the storage area 13; and a determination unit 15, which determines the installation state of the sensor module 20 based on the symmetry of the waveform data calculated by the calculation unit 14.

[0050] In addition to the voltage detector 12, the tire information sensing device 10 may also include a speed detector 16 for detecting vehicle speed or tire rotational speed, an air pressure detector 17 for detecting air pressure within the tire, or a temperature detector 18 for detecting temperature within the tire. Furthermore, the tire information sensing device 10 may also include additional input devices, output devices, displays, and other devices as appropriate.

[0051] In tire information sensing device 10, storage area 13, calculation unit 14, and determination unit 15 function as data processing device 19. Data processing device 19 processes data input from detection units, including voltage detection unit 12. Data input to data processing device 19 can be accomplished via either wired or wireless communication.

[0052] To acquire tire information, sensor module 20 includes at least element 11 and voltage detector 12. Sensor module 20 may also include sensors such as air pressure detector 17 and temperature detector 18, along with element 11 and voltage detector 12.

[0053] The element 11 is a component of the voltage detection unit 12 and is included in the voltage detection unit 12. The element 11 is not particularly limited as long as it is an element that can generate a voltage in proportion to the deformation (deformation energy) of the tread portion 1 during the rotation of the tire. For example, a piezoelectric element can be used as such an element 11. The piezoelectric element is configured in such a way that the element directly or indirectly abuts against the inner surface of the tire, and is configured to sense the deformation of the tread portion 1 through the element. The element indirectly abutting against the inner surface of the tire means, for example, that the element abuts against the inner surface of the tire via the housing of the sensor module 20 or the element is covered by a protective layer formed of rubber or the like so that the element abuts against the inner surface of the tire via the protective layer, and the deformation of the tread portion 1 can be sensed even if other components are sandwiched between the element and the inner surface of the tire. In this way, the piezoelectric element is a structure that generates voltage based on the deformation of the tread portion 1 during the rotation of the tire, so noise is not easily introduced and precise sensing can be performed.

[0054] The voltage detector 12 is a potential sensor that detects the potential difference across the charged element 11. Because the voltage detector 12 includes the element 11 that generates voltage based on the deformation of the tire tread 1 during rotation, it differs from a strain sensor that senses strain. Furthermore, the speed detector 16 can detect measurement data (vehicle speed) obtained by a vehicle-side speedometer, or it can detect the tire rotation speed using a sensor capable of detecting the tire's rotation speed. Furthermore, a pressure sensor can be used as the air pressure detector 17, and a temperature sensor can be used as the temperature detector 18.

[0055] The storage area 13 stores temporal waveform data of the voltage detected by the voltage detector 12. The storage area 13 may be formed of an external storage device such as a hard disk, an internal storage device such as a RAM (Random Access Memory), or a combination thereof. Figure 2 1 is a diagram showing waveform data stored in the storage area 13. Figure 2 The vertical axis represents voltage [V] and the horizontal axis represents elapsed time [μs], showing waveform data corresponding to one rotation of the tire T. During one rotation of the tire T, the waveform (voltage) reaches peak values ​​(maximum or minimum) when a point on the circumference of the tire T is at the front end of the ground contact and when it is at the rear end of the ground contact. Figure 3 FIG. 1 is a diagram showing another example of waveform data stored in the storage area 13. Figure 3In the waveform data d1, the data is for a new tire T, and the waveform data d2 is for a tire T in a state where the tread portion 1 is worn (later wear stage). That is, as the wear of the tread portion 1 of the tire T progresses, the peak voltages at the front and rear ends of the ground contact tend to increase. Figure 2 and Figure 3 The waveform data shown are data showing a representative example and are not limited thereto.

[0056] Furthermore, if the tire information sensing device 10 includes a speed detector 16, the storage area 13 stores the voltage waveform data detected by the voltage detector 12 together with the vehicle speed or tire rotational speed detected by the speed detector 16. Specifically, the vehicle speed or tire rotational speed is associated with the voltage waveform data and stored integrally in the storage area 13. Furthermore, if the tire information sensing device 10 includes an air pressure detector 17 and a temperature detector 18, the storage area 13 stores the voltage waveform data detected by the voltage detector 12 together with the air pressure and temperature detected by the air pressure detector 17 and the temperature detector 18. Specifically, the air pressure and temperature are associated with the voltage waveform data and stored integrally in the storage area 13.

[0057] When detecting the installation state of the sensor module 20, the calculation unit 14 calculates the symmetry of the waveform data, which serves as an indicator of the installation state of the sensor module 20, based on the waveform data stored in the storage area 13. In this process, the calculation unit 14 reads the waveform data stored in the storage area 13, performs the calculation, and stores the calculated indicator of the installation state of the sensor module 20 in the storage area 13. The calculation unit 14 can perform the calculation based on waveform data corresponding to multiple rotations of the tire T. To prevent erroneous judgments, waveform data corresponding to five or more rotations is preferably used.

[0058] Specifically, when calculating the symmetry of the waveform data, the calculation unit 14 extracts the first peak points p1 (in the waveform data) formed on both sides of the baseline BL of the waveform data based on the waveform data stored in the storage area 13. Figure 2 The second peak point p2 (in Figure 2 The waveform v is the point where the value is the minimum value, and any of the following operations (a) to (c) is performed. The baseline BL is the reference line of the value in the waveform data, and is not necessarily a line that represents zero as a value (in Figure 2The value B of the baseline BL is a voltage of 0 [V]. Furthermore, an approximate line obtained by removing high-frequency noise and a gentle displacement tendency (trend) through moving average processing can be used for the baseline BL. It should be noted that the symmetry of waveform data refers to the fact that waveforms v1 and v2 are point-symmetrical with respect to the intersection point O and line-symmetrical with respect to the waveform center axis M, but complete symmetry is not required.

[0059] (a) In the extracted waveform v, the calculation unit 14 calculates line segments SO and OF based on the intersection point O where the line L connecting the first peak point p1 and the second peak point p2 intersects the baseline BL, the start point S of the waveform v, and the end point F of the waveform v. The calculation unit 14 calculates the ratio of the short segment to the long segment in line segments SO and OF.

[0060] (b) In the extracted waveform v, the calculation unit 14 calculates the absolute value of the difference |P1-B| between the value P1 of the first peak point p1 and the value B of the baseline BL of the waveform data, and the absolute value of the difference |B-P2| between the value B of the baseline BL of the waveform data and the value P2 of the second peak point p2. The calculation unit 14 calculates the ratio |P1-B| / |B-P2| of the absolute value of the difference |P1-B| to the absolute value of the difference |B-P2|.

[0061] (c) In the extracted waveform v, the calculation unit 14 calculates the area A1 of the waveform v1 and the area A2 of the waveform v2 on both sides of the intersection point O where the line L connecting the first peak point p1 and the second peak point p2 intersects the baseline BL, and the waveform center axis M passing through the intersection point O and perpendicular to the baseline BL ( Figure 2 The calculation unit 14 calculates the ratio of the smaller area to the larger area of ​​the area A1 and the area A2.

[0062] When sensing tire T wear, the calculation unit 14 calculates a voltage change index value based on the waveform data stored in the storage area 13. In this case, the calculation unit 14 can store the calculated index value in the storage area 13, then read out the stored index value and perform the calculation. Here, the peak amplitude value between the maximum and minimum values ​​in the waveform data or the area of ​​the waveform data can be used as the voltage change index value. Furthermore, the calculation unit 14 can read out two voltage change index values ​​from the storage area 13 and calculate the rate of change of the other voltage change index value relative to one voltage change index value. The calculation unit 14 can be composed of, for example, a memory or a CPU (central processing unit).

[0063] Furthermore, when the tire information sensing device 10 includes the speed detection unit 16, the calculation unit 14 calculates an index value of voltage change based on waveform data within a predetermined speed range stored in the storage area 13 when sensing tire T wear. Here, the predetermined speed range is defined as a speed range having a lower limit of 5 km / h (desirable speed [km / h]) and an upper limit of 5 km / h (desirable speed). For example, the desired speed can be set within a range of 30 km / h to 60 km / h.

[0064] Furthermore, when tire information sensing device 10 includes air pressure detection unit 17 and temperature detection unit 18, calculation unit 14 can correct waveform data or a voltage change index value derived from the waveform data based on the air pressure detected by air pressure detection unit 17 and the temperature detected by temperature detection unit 18 when sensing tire T wear. In this case, calculation unit 14 reads the waveform data or voltage change index value stored in storage area 13, performs correction, and stores the corrected waveform data or voltage change index value in storage area 13.

[0065] When sensing the installation status of the sensor module 20, the determination unit 15 determines the installation status of the sensor module 20 based on the symmetry of the waveform data calculated by the calculation unit 14. Specifically, the determination unit 15 performs any one of the following determination processes (a) to (c). At this time, the determination unit 15 reads the symmetry index value of the waveform data from the storage area 13 and performs the determination. It should be noted that the determination unit 15 can be configured to calculate the ratio of the short segment to the long segment in the line segment SO and the line segment OF based on the line segment SO and the line segment OF calculated by the calculation unit 14.

[0066] (a) When the calculation unit 14 calculates the line segments SO and OF of the waveform v, the determination unit 15 determines that the sensor module 20 is mounted properly if the ratio of the short segment to the long segment in the line segments SO and OF is 0.4 to 1.0.

[0067] (b) When the calculation unit 14 calculates the absolute value of the difference |P1-B| and the absolute value of the difference |B-P2| of the waveform v, the determination unit 15 determines that the installation state of the sensor module 20 is good when the ratio |P1-B| / |B-P2| of the absolute value of the difference |P1-B| to the absolute value of the difference |B-P2| is 0.2 to 5.0.

[0068] (c) When the calculation unit 14 calculates the areas A1 and A2 of the waveform v, the determination unit 15 determines that the sensor module 20 is mounted properly if the ratio of the smaller area to the larger area of ​​the areas A1 and A2 is 0.4 to 1.0.

[0069] When sensing the wear of the tire T, the determination unit 15 compares the index value of the voltage change calculated by the calculation unit 14 with the reference information to determine the development state of the wear of the tread portion 1. At this time, the determination unit 15 reads the index value of the voltage change from the storage area 13 and performs the determination. The reference information compared with the index value of the voltage change is a benchmark for determining that the tread portion 1 is being worn. As reference information, the ratio of the index value of the voltage change relative to the time of a new product or a pre-set threshold value can be used. In a specific example, an arbitrary change rate [%] of the index value of the voltage change relative to the time of a new product can be set or a pre-verified threshold value can be set for a specific index value of the voltage change. It should be noted that the determination result obtained by the determination unit 15 can be displayed on a display provided on the vehicle, for example.

[0070] In addition, when the tire information sensing device 10 has a speed detection unit 16, when sensing the wear of the tire T, the judgment unit 15 compares the index value of the voltage change calculated by the calculation unit 14 with the reference information corresponding to the specified speed range to determine the development status of the wear of the tread portion 1.

[0071] Figure 4 This diagram illustrates the sequence of a sensing method using a tire information sensing device according to an embodiment of the present invention. To detect the installation status of sensor module 20 mounted on tire T and the wear progression of tread portion 1 of tire T, in step S1, voltage detection unit 12 of tire information sensing device 10 detects a voltage generated by deformation of tread portion 1 during rotation of tire T. At this time, storage area 13 stores waveform data of the voltage detected by voltage detection unit 12 over time.

[0072] Furthermore, in step S1, the speed detector 16 detects the vehicle speed or tire rotation speed, and the storage area 13 stores the waveform data of the voltage detected by the voltage detector 12 together with the vehicle speed or tire rotation speed detected by the speed detector 16. Furthermore, the air pressure detector 17 and the temperature detector 18 detect the air pressure and temperature, respectively, and the storage area 13 stores the waveform data of the voltage detected by the voltage detector 12 together with the air pressure and temperature detected by the air pressure detector 17 and the temperature detector 18.

[0073] Next, the process proceeds to step S2. The calculation unit 14 of the tire information sensing device 10 calculates the symmetry of the waveform data, serving as an indicator of the sensor module 20's installation status, based on the waveform data stored in the storage area 13. For example, within the extracted waveform v, the calculation unit 14 calculates line segments SO and OF based on the intersection point O, the start point S of the waveform v, and the end point F of the waveform v. The calculation unit 14 then calculates the ratio of the short segment to the long segment in line segments SO and OF. The calculation unit 14 then stores this calculated ratio of the short segment to the long segment in the storage area 13.

[0074] Next, the process proceeds to step S3, where the determination unit 15 of the tire information sensing device 10 determines the installation state of the sensor module 20 based on the symmetry of the waveform data calculated by the calculation unit 14. For example, if the calculation unit 14 calculates line segments SO and OF for the waveform v, the determination unit 15 concludes that the installation state of the sensor module 20 is good if the ratio of the short segment to the long segment in line segments SO and OF is between 0.4 and 1.0. If this is the case, the process proceeds to step S4; otherwise, the process returns to step S1.

[0075] Next, the process proceeds to step S4, where the calculation unit 14 of the tire information sensing device 10 corrects the voltage waveform data based on the air pressure and temperature detected by the air pressure detection unit 17 and the temperature detection unit 18. At this time, as part of the correction operation by the calculation unit 14, for example, when the air pressure detected by the air pressure detection unit 17 is relatively low, the overall tire variation tends to increase, and therefore, the waveform data tends to become larger overall. Therefore, the calculation unit 14 corrects the voltage waveform data so that it decreases by a predetermined ratio. This correction by the calculation unit 14 improves the accuracy of determining the progression of wear on the tread portion 1. The calculation unit 14 then stores the corrected waveform data in the storage area 13. It should be noted that the air pressure inside the tire fluctuates depending on the temperature inside the tire, so the temperature detected by the temperature detection unit 18 is used to correct the air pressure.

[0076] Then, the process proceeds to step S5, where the calculation unit 14 of the tire information sensing device 10 calculates the voltage change index value based on the waveform data within the specified speed range stored in the storage area 13. At this time, the calculation unit 14 can calculate the peak amplitude value between the maximum value and the minimum value in the waveform data as the voltage change index value (see Figure 5 (a)), the area of ​​the waveform data can also be calculated as an index value of the voltage change (refer to Figure 5 More specifically, the operation unit 14 is as follows: Figure 5 Calculate the peak amplitude value D1 [V] of the waveform data d1 as shown in (a) or as Figure 5As shown in (b), the area of ​​waveform data d1 (the area of ​​the shaded portion in the figure) is calculated. The calculation unit 14 then stores the calculated voltage change index value in the storage area 13. It should be noted that the peak amplitude value D1 calculated by the calculation unit 14 represents the value of the tire T when it is new.

[0077] Next, the process proceeds to step S6, where the determination unit 15 of the tire information sensing device 10 compares the voltage change index value calculated by the calculation unit 14 with reference information to determine the progression of wear on the tread portion 1. For example, the voltage change index value is set to the peak amplitude value, and the reference information for comparison is set to the rate of change relative to the peak amplitude value when the tire was new. If this rate of change is set to 150%, the determination unit 15 compares the rate of change based on the peak amplitude value calculated by the calculation unit 14 with the aforementioned pre-set rate of change (150%) and determines the magnitude relationship. If the pre-set rate of change exceeds this, the determination unit 15 concludes that the determination criteria are met. In this manner, if the determination criteria are met, the determination process ends. On the other hand, if the determination criteria are not met, the process returns to step S1.

[0078] It should be noted that in Figure 4 An example of determining the development status of wear after determining the installation status of the sensor module 20 is shown in the figure, but it is not limited to this. The process of the determination operation can be appropriately changed as follows: the determination of the installation status of the sensor module 20 and the determination of the development status of wear are performed in parallel, or when the installation status of the sensor module 20 is determined to be normal, the step of determining the installation status (S1 to S3) is omitted at any time.

[0079] The tire information sensing device 10 includes at least one sensor module 20 disposed on the inner surface of the tire, and a determination unit 15 that determines the installation status of the sensor module 20 based on the measurement values ​​supplied by the sensor module 20. Therefore, the measurement values ​​supplied by the sensor module 20 can be used to determine the installation status of the sensor module 20, and the wear progression of the tread portion 1 can be accurately sensed while the sensor module 20 is functioning normally. Furthermore, by utilizing the measurement values ​​supplied by the sensor module 20, it is unnecessary to provide additional equipment dedicated to determining the installation status of the sensor module 20, thereby avoiding increased costs. It should be noted that dedicated equipment for determining the installation status of the sensor module 20 may also be provided in the tire information sensing device 10.

[0080] In the above-described tire information sensing device, preferably, when sensing tire wear, the calculation unit 14 calculates line segments SO and OF based on the intersection O, the start point S of the waveform v, and the end point F of the waveform v. The determination unit 15 determines that the sensor module 20 is properly installed if the ratio of the short segment to the long segment in line segments SO and OF is between 0.4 and 1.0. This improves the accuracy of determining the installation status of the sensor module 20. Here, line segments SO and OF do not need to be identical, as long as the ratio of the short segment to the long segment is between 0.4 and 1.0. When the ratio of the short segment to the long segment is within the above range, the sensor module 20 is properly installed in the tire. When the ratio is less than 0.4, the sensor module 20 is not properly installed, and accurate sensing is not possible.

[0081] Furthermore, when sensing tire T wear, the calculation unit 14 may calculate the absolute value of the difference |P1-B| between the value P1 of the first peak point p1 and the value B of the baseline BL of the waveform data, and the absolute value of the difference |B-P2| between the value B of the baseline BL of the waveform data and the value P2 of the second peak point p2. The determination unit 15 may determine that the sensor module 20 is properly mounted if the ratio |P1-B| / |B-P2| of the absolute value of the difference |P1-B| to the absolute value of the difference |B-P2| is between 0.2 and 5.0. In this case, the calculation unit 14 preferably calculates these ratios based on waveform data representing at least ten rotations of the tire T, and the average value thereof is between 0.5 and 2.0. This improves the accuracy of determining the sensor module 20's mounted state. Here, when the above-mentioned ratio |P1-B| / |B-P2| is less than 0.2, poor sensing occurs at the front end of the tire's contact with the ground. Conversely, when it exceeds 5.0, poor sensing may occur at the rear end of the tire's contact with the ground, or the absolute value of the difference |P1-B| may be maximized due to damage to the base of the sensor module 20, etc.

[0082] Furthermore, when sensing tire wear on the tire T, the calculation unit 14 may calculate the areas A1 and A2 of the waveforms v1 and v2 on both sides of the intersection O and the waveform center axis M, and the determination unit 15 may determine that the sensor module 20 is properly installed if the ratio of the smaller area to the larger area of ​​area A1 and area A2 is between 0.4 and 1.0. This improves the accuracy of determining the installation status of the sensor module 20. Here, the areas A1 and A2 of the waveform v1 and v2 may differ as long as the ratio of the smaller area to the larger area is between 0.4 and 1.0. When the ratio of the smaller area to the larger area is within the above range, the sensor module 20 is properly installed in the tire. When the ratio of the smaller area to the larger area is less than 0.4, the sensor module 20 is not properly installed and cannot perform accurate sensing.

[0083] In the above description, in the tire information sensing device 10, waveform data of the tire T rotating one circle is used to calculate the index value of the voltage change, and the calculated index value is compared with the reference information to determine the wear of the tire T. However, waveform data of the tire T rotating multiple circles can also be used. Figure 6 1 is a diagram showing waveform data for a predetermined time stored in the storage area 13. That is, the waveform data for a predetermined time includes waveform data for a tire T to make a plurality of rotations. Figure 6 The dashed line represents a predetermined threshold value, and it can be seen that there are many locations exceeding the predetermined threshold value in the waveform data for a predetermined time. A case where waveform data for a plurality of rotations of the tire T is used will be described.

[0084] In the tire information sensing device 10, when sensing tire T wear, the calculation unit 14 calculates the frequency of excess relative to a predetermined threshold value based on waveform data stored in the storage area 13 within a predetermined speed range and a predetermined time period. Furthermore, the calculation unit 14 can store the calculated waveform data in the storage area 13 and then read out the stored waveform data to perform the calculation.

[0085] Here, the prescribed speed range refers to a speed range with an arbitrary speed [km / h] - 5km / h as the lower limit and an arbitrary speed + 5km / h as the upper limit. As the arbitrary speed, it can be set within the range of 30km / h to 60km / h, for example. In addition, as the prescribed time, it can be set within the range of 0.1 [second] to 10.0 [seconds]. Moreover, as the prescribed threshold value, it can be set to a voltage [V] that can be used to determine that the tread portion 1 is wearing based on the above-mentioned prescribed speed range and prescribed time. As for the prescribed threshold value, both the upper limit range and the lower limit range or only one of them can be set. Moreover, the prescribed threshold value can be appropriately determined based on the tire size, for example.

[0086] Furthermore, when sensing tire T wear, if the tire information sensing device 10 includes an air pressure detector 17 and a temperature detector 18, the calculation unit 14 can correct waveform data or a predetermined threshold value based on the air pressure detected by the air pressure detector 17 and the temperature detected by the temperature detector 18. In this case, the calculation unit 14 reads the waveform data or the predetermined threshold value within a predetermined speed range and a predetermined time period stored in the storage area 13, performs correction, and stores the corrected waveform data or the predetermined threshold value in the storage area 13.

[0087] When sensing wear of the tire T, the determination unit 15 determines the progression of wear of the tread portion 1 based on the frequency of excess relative to a predetermined threshold value calculated by the calculation unit 14. At this time, the determination unit 15 reads waveform data within a predetermined speed range and a predetermined time from the storage area 13 and performs the determination.

[0088] In addition, Figure 4 In steps S1 to S3, the tire information sensing device 10 functions in the same manner, but Figure 4 In step S4, the calculation unit 14 of the tire information sensing device 10 may correct the voltage waveform data or a predetermined threshold value based on the air pressure and temperature detected by the air pressure detection unit 17 and the temperature detection unit 18. At this time, as a correction operation of the calculation unit 14, for example, when the air pressure detected by the air pressure detection unit 17 is relatively low, the overall change in the tire tends to increase, and as a result, the waveform data also tends to become larger overall. Therefore, the calculation unit 14 corrects the voltage waveform data in a manner that reduces it at a predetermined rate. By performing such correction by the calculation unit 14, the accuracy of determining the progress of wear of the tread portion 1 can be improved. The calculation unit 14 then stores the corrected waveform data or the predetermined threshold value in the storage area 13. It should be noted that the air pressure inside the tire fluctuates according to the temperature inside the tire, and therefore the temperature detected by the temperature detection unit 18 is used to correct the air pressure.

[0089] exist Figure 4 In step S5, the calculation unit 14 of the tire information sensing device 10 may calculate the frequency of excess relative to a predetermined threshold value based on the waveform data within a predetermined speed range and a predetermined time stored in the storage area 13. In this case, the calculation unit 14 performs masking on the waveform data based on the predetermined threshold value to calculate the frequency of excess. Specifically, masking is performed to extract the amount exceeding the predetermined threshold value, and based on the waveform data after the masking process (see Figure 7 ), the number of locations exceeding a predetermined threshold is counted, thereby calculating the excess frequency. Then, the calculation unit 14 stores the waveform data after the calculation in the storage area 13.

[0090] exist Figure 4In step S6, the determination unit 15 of the tire information sensing device 10 may determine the development state of the wear of the tread portion 1 based on the frequency of excess relative to a prescribed threshold value calculated by the calculation unit 14. For example, when the determination criterion for the frequency of excess is pre-set to 15 times, the determination unit 15 derives the following conclusion: if the frequency of excess of waveform data at a certain point in time is 10 times, the determination criterion is not satisfied, and if the frequency of excess of waveform data at other points in time is 15 times, the determination criterion is satisfied. The determination criterion can be set, for example, as the number of excesses relative to a prescribed threshold value or as a ratio relative to the number of excesses when the product is new. In this way, the determination operation is terminated when the determination criterion is satisfied. On the other hand, when the determination criterion is not satisfied, the process returns to step S1. Alternatively, when the installation state of the sensor module 20 has been determined to be normal, the steps of determining the installation state (S1 to S3) may be omitted for an arbitrary period (for example, it can be set to 1 minute to 1 week). As described above, the tire information sensing device 10 functions differently when utilizing waveform data corresponding to multiple rotations of the tire T than when utilizing waveform data corresponding to one rotation of the tire T. However, in either case, the wear progression of the tread portion 1 can be accurately sensed.

[0091] Figure 8 FIG. 1 is a diagram showing a modified example of the sequence of the sensing method using the tire information sensing device according to the embodiment of the present invention. Figure 8 In the embodiment, the determination unit 15 of the tire information sensing device 10 performs at least two determination operations and finally determines the progress state of wear of the tread portion 1 based on the results of these determination operations. Figure 8 The order shown is the same as Figure 4The sequence shown is the same until step S6. Following step S6, the process proceeds to step S7, where the voltage detector 12 detects the voltage generated by element 11, and the speed detector 16 detects the vehicle speed or tire rotation speed. The process then proceeds to step S8, where the calculation unit 14 corrects the waveform data or a predetermined threshold value based on the air pressure and temperature detected by the air pressure detector 17 and the temperature detector 18. The calculation unit 14 then stores the corrected waveform data or the predetermined threshold value in the storage area 13. The process then proceeds to step S9, where the calculation unit 14 calculates a voltage change index value or a frequency of exceeding a predetermined threshold value based on the waveform data within a predetermined speed range or a predetermined speed range and a predetermined time period stored in the storage area 13. The calculation unit 14 then stores the calculated voltage change index value or waveform data in the storage area 13. The process then proceeds to step S10, where the determination unit 15 performs a second determination operation. If any of the determination criteria are met, the determination operation ends. On the other hand, if the criteria are not met, the process returns to step S7. Here, when the determination unit 15 performs the second determination operation, the first determination operation (steps S4 to S6 ) and the second determination operation (steps S7 to S10 ) may be performed on the same day or on different days.

[0092] As described above, by the determination unit 15 performing the determination operation at least twice, it is possible to suppress the occurrence of sudden errors in the final determination result, and to improve the accuracy of the determination of the progress state of wear of the tread portion 1 .

[0093] It should be noted that in Figure 8 In the embodiment, an example is shown in which the number of determinations performed by the determination unit 15 is set to two, but this is not particularly limited and can be set to any number as long as it is multiple. Figure 8 In the embodiment, an example is shown in which the process returns to step S7 when the determination criterion is not satisfied in step S10, but the process may also return to step S1 when the determination criterion is not satisfied in step S10.

[0094] Figure 9 1 is a diagram showing a pneumatic tire (tire T) determined by the tire information sensing device 10 according to the embodiment of the present invention. Figures 10 to 12 FIG is a diagram showing the sensor module 20 or the container 30 mounted on the tire T. Figure 10 and Figure 12 In FIG. 1 , arrow Tc indicates the tire circumferential direction, and arrow Tw indicates the tire width direction.

[0095] like Figure 9As shown, the tire T includes: a tread portion 1 extending in a ring shape in the tire circumferential direction; a pair of sidewall portions 2, 2 arranged on both sides of the tread portion 1; and a pair of bead portions 3, 3 arranged on the inner side of the sidewall portion 2 in the tire radial direction.

[0096] A 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 folded back from the inside of the tire to the outside around a bead core 5 disposed in each bead portion 3. A bead core 6 formed of a rubber composition and having a triangular cross-section is disposed on the outer circumference of the bead core 5. Furthermore, an inner liner layer 9 is disposed in the area between the pair of bead portions 3, 3 on the tire inner surface Ts. The inner liner layer 9 forms the tire inner surface Ts.

[0097] On the other hand, a plurality of belt layers 7 are embedded on the outer peripheral side of the carcass layer 4 at the tread portion 1. These belt layers 7 are configured to include a plurality of reinforcing cords inclined relative to the tire circumferential direction, and the reinforcing cords cross each other between layers. In the belt layer 7, the inclination angle of the reinforcing cords relative to the tire circumferential direction is set, for example, in the range of 10° to 40°. As the reinforcing cords of the belt layer 7, steel cords are preferably used. For the purpose of improving high-speed durability, at least one belt covering layer 8 is provided on the outer peripheral side of the belt layer 7, in which reinforcing cords are arranged at an angle of, for example, less than 5° relative to the tire circumferential direction. As the reinforcing cords of the belt covering layer 8, organic fiber cords such as nylon and aramid are preferably used.

[0098] It should be noted that the above-described tire internal structure is a structure showing a representative example of a pneumatic tire, but is not limited thereto.

[0099] At least one rubber container 30 is fixed to the area corresponding to the tread portion 1 of the tire inner surface Ts of the tire T. The container 30 is for inserting the sensor module 20. The container 30 has an opening 31 for inserting the sensor module 20 and is bonded to the tire inner surface Ts via an adhesive layer 32. The sensor module 20 is configured to be freely accommodated in the container 30, so that it can be appropriately replaced when the sensor module 20 is replaced or when a malfunction occurs. In addition, since the container 30 is made of rubber, it can be expanded and contracted when the sensor module 20 is inserted into and removed from the opening 31, which is preferable.

[0100] Examples of materials for the container 30 include chloroprene rubber (CR), isobutylene rubber (IIR), natural rubber (NR), acrylonitrile-butadiene rubber (NBR), butadiene rubber (BR), and styrene-butadiene rubber (SBR). These materials may be used alone or as a mixture of two or more. These materials have excellent adhesion to the butyl rubber forming the tire inner surface Ts. Therefore, when the container 30 is formed of these materials, sufficient adhesion between the container 30 and the tire inner surface Ts is ensured.

[0101] like Figure 12 As shown, the sensor module 20 includes a housing 21 and electronic components 22. The housing 21 has a hollow structure and houses the electronic components 22. The electronic components 22 can be configured to appropriately include a transmitter, a receiver, a control circuit, a battery, etc., together with a sensor 23 for acquiring tire information such as the voltage, speed, air pressure, and temperature of the tire T. As the sensor 23, for example, a speed sensor (speed detection unit 16), a pressure sensor (air pressure detection unit 17), or a temperature sensor (temperature detection unit 18) can be used together with a piezoelectric sensor (element 11 and voltage detection unit 12). In particular, the piezoelectric sensor includes an element 11 that generates a voltage based on the deformation of the tread portion 1 during tire rotation. This piezoelectric sensor is different from a piezoelectric acceleration sensor. In addition to the various sensors described above, an acceleration sensor or a magnetic sensor can also be used. In addition, the sensor module 20 is configured to be able to send the tire information acquired by the sensor 23 to the storage area 13. Furthermore, in order to facilitate gripping of the sensor module 20, a handle portion 24 protruding from the housing 21 may be provided, and the handle portion 24 may function as an antenna. Figure 12 The internal structure of the sensor module 20 shown is an example of the structure of the sensor module and is not limited thereto.

[0102] The container 30 is joined to the inner surface Ts of the tire through an adhesive layer 32. The container 30 has a plate-shaped base 33 joined to the inner surface Ts of the tire, a cylindrical barrel 34 protruding from the base 33, and a container 35 formed in the barrel 34. The container 35 is connected to the circular opening 31. In this way, the container 35 has a roughly quadrilateral cross-sectional shape with the base 33 as the bottom surface and the opening 31 as the upper surface. The container 35 accommodates the cylindrical sensor module 20 with a tapered upper surface. It should be noted that the shapes of the base 33, the barrel 34 and the container 35 are not particularly limited and can be appropriately changed according to the shape of the sensor module 20 inserted into the container 30.

[0103] The adhesive layer 32 is not particularly limited, as long as it is a layer that can adhere to the rubber composition. For example, as the adhesive layer 32, it is preferable to use a cyanoacrylate-based adhesive (instant adhesive) or a polyurethane-based adhesive. In the case of a cyanoacrylate-based adhesive, the operation time of arranging the container 30 on the tire inner surface Ts can be shortened. In the case of a polyurethane-based adhesive, it has excellent adhesion to vulcanized rubber and is therefore preferred. In addition, as the adhesive layer 32, adhesive tape, naturally vulcanized (vulcanizable at room temperature) vulcanized adhesive, or a flat tire repair agent used as an emergency treatment in the case of a pneumatic tire leak can be used. When a vulcanized adhesive is used as the adhesive layer 32, the primer treatment required to fix the container using adhesive tape or the like can be omitted, which can improve productivity. It should be noted that primer treatment (primer treatment) refers to a treatment pre-implemented on the tire inner surface in order to improve adhesion.

[0104] In the above-mentioned pneumatic tire, at least one rubber container 30 for inserting the sensor module 20 is provided on the inner surface Ts of the tire. The container 30 has a plate-shaped base 33 joined to the inner surface Ts of the tire through an adhesive layer 32, a barrel 34 protruding from the base 33, a container 35 formed in the barrel 34, and an opening 31 connected to the container 35. Therefore, the operation of inserting the sensor module 20 into the container 30 is easy, and the sensor module 20 can be reliably held by tightening the container 30 to prevent the sensor module 20 from falling off.

[0105] In the above pneumatic tire, preferably, the housing 30 is joined to the inner surface Ts of the tire through an adhesive layer 32. As the roughness of the inner surface Ts of the tire, the arithmetic mean 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. By appropriately setting the arithmetic mean height Sa and the maximum height Sz as the roughness of the inner surface Ts of the tire in this way, the adhesion area between the inner surface Ts of the tire and the adhesive layer 32 can be increased, and the adhesion between the inner surface Ts of the tire and the housing 30 can be effectively improved. When the arithmetic mean height Sa exceeds 15.0 μm and the maximum height Sz exceeds 60.0 μm, the adhesive layer 32 cannot follow the unevenness of the inner surface Ts of the tire, and the adhesion tends to decrease. It should be noted that the arithmetic mean height Sa and the maximum height Sz are values measured according to ISO25178, and can be measured using a commercially available surface property measuring instrument (such as a shape analysis laser microscope, a 3D shape measuring instrument). The measuring method can be either a contact type or a non-contact type.

[0106] In Figure 9 and Figure 11 , the housing 30 is disposed on the inner side in the tire width direction compared with the grounding end. In addition, the housing 30 may be biased to one side existing in the tire width direction with respect to the tire center line CL. The sensor 23 inserted into the sensor module 20 of the housing 30 can accurately acquire tire information.

[0107] In the above pneumatic tire, it is preferable that the housing 30 is set to the following dimensions. Preferably, the width Lc1 of the opening 31 of the housing 30 and the inner width Lc2 of the bottom surface of the housing 30 satisfy the relationship of Lc1 < Lc2. By making the width Lc1 of the opening 31 narrower than the inner width Lc2 of the bottom surface of the container 30 in this way, the binding force on the upper surface side of the housing 30 can be enhanced, and the sensor module 20 inserted into the housing 30 can be effectively prevented from falling off. Thereby, the workability when inserting the sensor module 20 and the holding property of the housing 30 can be taken into account. It should be noted that the width Lc1 of the opening 31 and the inner width Lc2 of the bottom surface in the housing 30 are both widths measured in the state where the sensor module 20 is not inserted into the housing 30.

[0108] In addition, preferably, the average thickness of the housing 30 is 0.5 mm to 5.0 mm. By appropriately setting the average thickness of the housing 30 in this way, the workability when inserting the sensor module 20, the retention of the housing 30, and the fracture resistance of the housing 30 can be improved with good balance. Here, when the average thickness of the housing 30 is thinner than 0.5 mm, the housing 30 is likely to break when inserting the sensor module 20, and when the average thickness of the housing 30 is thicker than 5.0 mm, the rigidity of the housing 30 becomes too large and it is impossible to easily insert the sensor module 20. It should be noted that the average thickness of the housing 30 is the thickness obtained by measuring the thickness of the rubber constituting the housing 30.

[0109] Particularly preferably, the housing 30 and the sensor module 20 satisfy the following dimensional relationship. Regarding the width Lc1 of the opening 31 of the housing 30 and the maximum width Lsm of the sensor module 20 inserted into the housing 30, preferably, the relationship 0.10 ≤ Lc1 / Lsm ≤ 0.95 is satisfied, more preferably, the relationship 0.15 ≤ Lc1 / Lsm ≤ 0.80 is satisfied, and most preferably, the relationship 0.15 ≤ Lc1 / Lsm ≤ 0.65 is satisfied. By appropriately setting the ratio of the width Lc1 of the opening 31 of the housing 30 to the maximum width Lsm of the sensor module 20 in this way, the detachment of the sensor module 20 can be effectively prevented, and the workability when inserting the sensor module 20 and the retention of the housing 30 can be improved. It should be noted that in Figure 12 the sensor module 20, the maximum width Lsm corresponds to the width Ls2 of the lower surface.

[0110] In addition, preferably, the width Lc1 of the opening 31 of the housing 30, the inner width Lc2 of the bottom surface of the housing 30, the width Ls1 of the upper surface of the sensor module 20, and the width Ls2 of the lower surface of the sensor module 20 satisfy the relationship Lc1 < Ls1 ≤ Ls2 ≤ Lc2. Moreover, more preferably, the upper surface of the sensor module 20 is formed in a conical shape, satisfying the relationship Ls1 < Ls2. By appropriately setting the respective widths of the housing 30 and the sensor module 20 in this way, the detachment of the sensor module 20 can be effectively prevented. In addition, in the sensor module 20, a form in which the diameter gradually decreases from its upper surface to its lower surface can also be adopted. In this case, preferably, the relationships Ls2 < Ls1 and Ls2 ≤ Lc2 and Lc1 < Ls1 are satisfied.

[0111] Furthermore, the ratio of the height Hc of the container 30 in the state where the sensor module 20 is inserted to the height (maximum height) Hs of the sensor module 20 is preferably 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. By appropriately setting the ratio of the height Hc of the container 30 to the height Hs of the sensor module 20 in this manner, the sensor module 20 can be effectively prevented from falling off. It should be noted that, in the case where the sensor module 20 is provided with a handle portion 24, the height Hs of the sensor module 20 is the height including the handle portion 24 (see Figure 12 ). In addition, the height Hc of the container 30 is the height of the cylinder 34 and does not include the height of the base 33 (see Figure 12 ).

[0112] In the pneumatic tire described above, the rubber constituting the container 30 preferably has the following physical properties. Preferably, the elongation at break (EB) is 50% to 900%, and the modulus (M300) at 300% elongation is 2 MPa to 15 MPa. By appropriately setting the elongation at break (EB) and the modulus (M300), the ease of inserting the sensor module 20, the retention of the container 30, and the fracture resistance of the container 30 can be improved in a well-balanced manner.

[0113] Example

[0114] The following tires of Examples 1 to 6 were produced: tire size 275 / 40R21, comprising: at least one sensor module disposed on the inner surface of the tire; an element mounted on the sensor module and generating a voltage based on deformation of the tread portion during tire rotation; a voltage detection unit detecting the voltage generated by the element; a storage area storing waveform data of the voltage detected by the voltage detection unit over time; a calculation unit calculating the symmetry of the waveform data as an index value of the sensor module's installation state based on the waveform data stored in the storage area, and calculating an index value of voltage change based on the waveform data stored in the storage area; and a determination unit determining the installation state of the sensor module based on the symmetry of the waveform data calculated by the calculation unit, and determining the progression of tread wear by comparing the index value of voltage change calculated by the calculation unit with reference information. The sensor module is fixed to the inner surface of the tire by a housing that accommodates the sensor module. The housing has an opening for inserting the sensor module, and the ratio (Lc1 / Lsm) of the width Lc1 of the opening to the maximum width Lsm of the sensor module is set as shown in Table 1.

[0115] For these test tires, the mounting state sensing performance, wear sensing performance, workability when inserting the sensor module, and durability were evaluated by the following test methods. The results are collectively shown in Table 1.

[0116] Installation status sensing performance:

[0117] For each test tire, the installation status of the sensor module was determined by the tire information sensing device. For example, in the tire of Example 1, the following Figure 2 The waveform data is shown. As shown in the figure, it can be confirmed that the waveform data is symmetrical when the sensor module is properly installed. In other words, the waveform data is useful as an indicator of the sensor module's installation condition, and a correlation is confirmed between the voltage and the sensor module's installation condition. In Examples 2 to 6, where there is also a correlation between the voltage and the sensor module's installation condition, this is indicated as "good" in Table 1.

[0118] Wear sensing performance:

[0119] For each test tire, the wear development state of the tread portion was determined by the tire information sensing device. For example, in the tire of Example 1, the following Figure 13 The waveform data is shown. As shown in the figure, it can be confirmed that as the tread wear progresses from the new tread A to the later stage of wear D (the ratio of the groove depth at each time point to the new tread depth decreases), the peak amplitude value of the waveform data at each time point gradually increases. In other words, the peak amplitude value of the waveform data is useful as an indicator of voltage changes, and a correlation is confirmed between voltage and groove depth. In Examples 2 to 6, there is also a correlation between voltage and groove depth, which is indicated as "Good" in Table 1.

[0120] Workability when inserting the sensor module:

[0121] For each test tire, the time required to insert the sensor module into the housing located on the inner surface of the tire was measured. The evaluation results were expressed as an index using the reciprocal of the measured value, with Example 1 set to 100. A larger index value indicates easier sensor module insertion.

[0122] Durability:

[0123] Each test tire was mounted on a wheel with a rim size of 21×9.5J. A running test was conducted using a drum tester under the conditions of an air pressure of 120 kPa, a load of 102% relative to the maximum load, a speed of 81 km / h, and a distance of 10,000 km. The tires were then visually inspected for damage to the housing or detachment of the sensor module. The evaluation results indicated the presence of damage to the housing and detachment of the sensor module.

[0124] [Table 1]

[0125]

[0126] As shown in Table 1, the tire information sensing devices of Examples 1 to 6 exhibited excellent mounting status sensing performance and wear sensing performance. The pneumatic tires of Examples 2 to 6 exhibited improved sensor module insertion operability compared to Example 1. The pneumatic tires of Examples 3 to 5 experienced no damage to the housing or detachment of the sensor module.

[0127] Description of Reference Numerals

[0128] 1: tread;

[0129] 2: side wall;

[0130] 3: bead part;

[0131] 10: Tire information sensing device;

[0132] 11: Component;

[0133] 12: voltage detection unit;

[0134] 13: storage area;

[0135] 14: Operation unit;

[0136] 15: Judgment Department;

[0137] 16: speed detection unit;

[0138] 17: Air pressure detection unit;

[0139] 18: Temperature detection unit;

[0140] 20: sensor module;

[0141] 30: containing body;

[0142] Ts: tire inner surface;

[0143] CL: Tire center line.

Claims

1. A tire information sensing device for sensing tire information including at least one of tire wear, tire deformation, road surface condition, tire contact state, presence or absence of tire faults, tire driving history, and tire load state, the tire information sensing device comprising: at least one sensor module disposed on an inner surface of a tire; and a determination unit for determining a mounting state of the sensor module based on a measurement value supplied by the sensor module. The tire information sensing device includes: an element mounted on the sensor module, which generates a voltage based on the deformation of the tread portion during tire rotation; a voltage detection unit, which detects the voltage generated by the element; a storage area, which stores waveform data of the voltage detected by the voltage detection unit over time; and a calculation unit, which calculates the symmetry of the waveform data as an indicator value of the installation status of the sensor module based on the waveform data stored in the storage area, and the determination unit determines the installation status of the sensor module based on the symmetry of the waveform data calculated by the calculation unit.

2. The tire information sensing device according to claim 1, characterized in that: The calculation unit extracts a waveform including a first peak point and a second peak point formed on both sides of the baseline of the waveform data, and calculates a line segment SO and a line segment OF based on an intersection point O where a line connecting the first peak point and the second peak point intersects the baseline of the waveform data, a start point S of the waveform, and an end point F of the waveform. When the ratio of the short segment to the long segment in the line segment SO and the line segment OF is 0.4 to 1.0, the determination unit determines that the mounting state of the sensor module is good.

3. The tire information sensing device according to claim 1, wherein: The calculation unit extracts a waveform including a first peak point and a second peak point formed on both sides of the baseline of the waveform data, calculates an absolute value of a difference |P1-B| between a value P1 of the first peak point and a value B of the baseline of the waveform data, and calculates an absolute value of a difference |B-P2| between the value B of the baseline of the waveform data and a value P2 of the second peak point, The determination unit determines that the mounting state of the sensor module is good when the ratio |P1-B| / |B-P2| of the absolute value of the difference |P1-B| to the absolute value of the difference |B-P2| is 0.2 to 5.

0.

4. The tire information sensing device according to claim 1, wherein: The calculation unit extracts a waveform including a first peak point and a second peak point formed on both sides of the baseline of the waveform data, calculates an intersection point O where a line connecting the first peak point and the second peak point intersects the baseline of the waveform data, and calculates areas A1 and A2 of the waveform on both sides of a waveform center axis passing through the intersection point O and perpendicular to the baseline of the waveform data. When the ratio of the smaller area to the larger area of ​​the area A1 and the area A2 is 0.4 to 1.0, the determination unit determines that the mounting state of the sensor module is good.

5. The tire information sensing device according to any one of claims 1 to 4, characterized in that: The calculation unit calculates a voltage change index value based on the waveform data stored in the storage area, and the determination unit compares the voltage change index value calculated by the calculation unit with reference information to determine a wear progression state of the tread portion.

6. The tire information sensing device according to any one of claims 1 to 4, characterized in that: There is a speed detection unit for detecting the vehicle speed or the rotational speed of the tire. The storage area stores the waveform data of the voltage detected by the voltage detection unit over time together with the vehicle speed or the rotational speed of the tire detected by the speed detection unit. The arithmetic unit calculates an index value of the voltage change based on the waveform data within a specified speed range stored in the storage area. The determination unit compares the index value of the voltage change calculated by the arithmetic unit with reference information corresponding to the specified speed range to determine the development state of the wear of the tread surface.

7. The tire information sensing device according to claim 5, characterized in that: The arithmetic unit calculates the peak amplitude value between the maximum value P1 and the minimum value P2 in the waveform data as the index value of the voltage change.

8. The tire information sensing device according to any one of claims 1 to 4, characterized in that: There is a speed detection unit for detecting the vehicle speed or the rotational speed of the tire. The storage area stores the waveform data of the voltage detected by the voltage detection unit over time together with the vehicle speed or the rotational speed of the tire detected by the speed detection unit. The arithmetic unit calculates the exceedance frequency relative to a specified threshold based on the waveform data within a specified speed range and within a specified time stored in the storage area. The determination unit determines the development state of the wear of the tread surface based on the exceedance frequency relative to the specified threshold calculated by the arithmetic unit.

9. The tire information sensing device according to claim 8, characterized in that: There is a pressure detection unit for detecting the air pressure inside the tire. The arithmetic unit corrects the waveform data or the specified threshold based on the air pressure detected by the pressure detection unit.

10. The tire information sensing device according to claim 5, characterized in that: The determination unit performs at least two determination operations and finally determines the development state of the wear of the tread surface based on the results of these determination operations.

11. The tire information sensing device according to claim 5, characterized in that: The sensor module at least includes the element and the voltage detection unit. The sensor module is fixed to the inner surface of the tire through a housing into which the sensor module is inserted.

12. The tire information sensing device according to claim 11, characterized in that: The housing is joined to the inner surface of the tire through an adhesive layer. As the roughness of the inner surface of the tire, the arithmetic mean 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.

13. The tire information sensing device according to claim 11, wherein: The width Lc1 of the opening of the housing and the inner width Lc2 of the bottom surface of the housing satisfy the relationship Lc1 < Lc2.

14. The tire information sensing device according to claim 11, wherein: The width Lc1 of the opening of the housing and the maximum width Lsm of the sensor module satisfy the relationship 0.10 ≤ Lc1 / Lsm ≤ 0.

95.

15. The tire information sensing device according to claim 11, characterized in that: The width Lc1 of the opening of the housing, the inner width Lc2 of the bottom surface of the housing, the width Ls1 of the upper surface of the sensor module, and the width Ls2 of the lower surface of the sensor module satisfy the relationship Lc1 < Ls1 ≤ Ls2 ≤ Lc2.

16. The tire information sensing device according to claim 11, wherein: The average thickness of the housing is 0.5 mm to 5.0 mm.

17. The tire information sensing device according to claim 11, wherein: The ratio of the height Hc of the housing in the state where the sensor module is inserted to the height Hs of the sensor module is in the range of 0.5 to 1.

5.

18. The tire information sensing device according to claim 11, wherein: The elongation at break EB of the rubber constituting the housing is 50% to 900%, and the modulus of the rubber constituting the housing at 300% elongation is 2 MPa to 15 MPa.

19. The tire information sensing device according to claim 11, wherein: The housing is arranged on the inner side in the tire width direction relative to the ground contact end.

20. The tire information sensing device according to any one of claims 1 to 4, characterized in that: The element is a piezoelectric element.

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