Tire monitoring system and tire monitoring method

Abstract

To provide a technique capable of improving maintainability by determining a cause of a defect in a tire.SOLUTION: A tire monitoring system 100 comprises: an information acquisition unit 32; a temperature determination unit 33; and an air pressure determination unit 34. The information acquisition unit 32 acquires measurement data from an air pressure sensor 11 and a temperature sensor 12 provided in a plurality of tires 1 fitted to a vehicle. The temperature determination unit 33 calculates a temperature change amount of each tire 1 on the basis of the measurement data acquired by the information acquisition unit 32, and determines whether a difference value between the temperature change amount of at least one tire which is largest and the temperature change amount of the other tire is larger than a prescribed threshold value. The air pressure determination unit 34 determines, when the temperature determination unit 33 determines that the difference value is larger than the threshold value, which of the vehicle side and the tire side has a defect on the basis of the measurement data of air pressure.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a tire monitoring system and a tire monitoring method for managing tires mounted on a vehicle. [Background technology]

[0002] Tires mounted on a vehicle are set to an appropriate air pressure, and if the air pressure drops, the tires are filled with air as part of maintenance so that the appropriate air pressure is restored.

[0003] A conventional tire failure prediction system is described in Patent Document 1. This tire failure prediction system determines that there is a possibility of failure in the first tire when the temperature value of a first tire exceeds a predetermined threshold and the difference between the temperature value of the first tire and the temperature value of a second tire exceeds a predetermined first temperature difference threshold. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-111126 Summary of the Invention [Problem to be solved by the invention]

[0005] In the tire failure prediction system described in Patent Document 1, for example, when the outside air temperature is low in winter, the temperature value of the first tire may not exceed a predetermined threshold value, and the possibility of tire failure may not be determined.

[0006] The present invention has been made in consideration of the above circumstances, and its object is to provide a tire monitoring system and a tire monitoring method that can determine the cause of a defect in a tire and improve maintainability. [Means for solving the problem]

[0007] A tire monitoring system according to one embodiment of the present invention comprises an information acquisition unit that acquires measurement data from air pressure sensors and temperature sensors attached to multiple tires mounted on a vehicle; a temperature determination unit that calculates the amount of temperature change in each tire based on the measurement data acquired by the information acquisition unit and determines whether the difference between the amount of temperature change in at least one tire with the largest amount of temperature change and the amount of temperature change in other tires is greater than a predetermined threshold; and an air pressure determination unit that, if the temperature determination unit determines that the difference is greater than the predetermined threshold, determines whether a malfunction has occurred on the vehicle side or on the tire side based on the air pressure measurement data.

[0008] Another aspect of the present invention is a tire monitoring method, which includes an information acquisition step of acquiring measurement data from air pressure sensors and temperature sensors provided in multiple tires mounted on a vehicle, a temperature determination step of calculating a temperature change amount for each tire based on the measurement data acquired in the information acquisition step and determining whether a difference between the temperature change amount of at least one tire with the largest temperature change amount and the temperature change amounts of the other tires is greater than a predetermined threshold, and an air pressure determination step of determining whether a problem has occurred on the vehicle side or on the tire side based on the air pressure measurement data if the temperature determination step determines that the difference amount is greater than the predetermined threshold. [Effects of the Invention]

[0009] According to the present invention, it is possible to determine whether a temperature abnormality in a tire is caused by the vehicle side or the tire side, thereby improving maintainability. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing the overall configuration of a tire monitoring system according to an embodiment; [Figure 2] FIG. 2 is a block diagram showing the functional configuration of the tire monitoring device. [Figure 3] 4 is a flowchart showing a procedure for a malfunction determination process performed by the tire monitoring system. [Figure 4] 1 is a graph showing an example of tire temperature when a tire malfunction occurs. [Figure 5] 10 is a graph showing an example of tire pressures for which the cause of a malfunction is determined to be due to the vehicle. [Figure 6] FIG. 10 is a block diagram showing a functional configuration of a tire monitoring device according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described below based on preferred embodiments with reference to Figures 1 to 6. The same or equivalent components and members shown in each drawing are designated by the same reference numerals, and duplicate descriptions will be omitted where appropriate. The dimensions of the members in each drawing are enlarged or reduced as appropriate to facilitate understanding. Some members that are not important for explaining the embodiments will be omitted from the drawings.

[0012] (Embodiment) 1 is a schematic diagram showing the overall configuration of a tire monitoring system 100 according to an embodiment. The tire monitoring system 100 includes a sensor 10, a vehicle measurement device 20, a tire monitoring device 30, and a user terminal device 40. The tire monitoring system 100 acquires and monitors measurement data such as the air pressure and temperature of tires 1 measured by sensors 10 disposed on multiple tires 1 mounted on a vehicle 7.

[0013] The vehicles 7 are, for example, multiple transport trucks operated and managed by a transport company or the like. The tire monitoring device 30 of the tire monitoring system 100 acquires and monitors measurement data such as air pressure and temperature of multiple tires 1 mounted on each of the multiple vehicles 7. The tire monitoring device 30 may acquire and monitor measurement data such as air pressure and temperature of tires 1 for a single vehicle.

[0014] The tire monitoring device 30 calculates the amount of temperature change for multiple tires 1 mounted on the vehicle 7, and determines whether the difference between the amount of temperature change in at least one tire 1 and the amount of temperature change in the other tires 1 is greater than a predetermined threshold. If the tire monitoring device 30 determines that the difference between the amount of temperature change in one tire 1 and the amount of temperature change in the other tires 1 is greater than the predetermined threshold, it determines whether the problem is caused by the vehicle side or the tire side, based on the tire pressure measurement data.

[0015] The tire monitoring device 30 generates alert information that indicates a possible malfunction and includes a determination result as to whether the malfunction is caused by the vehicle or the tire, and notifies the outside. The tire monitoring device 30 notifies the outside by displaying the alert information on a display device provided in the device itself. The tire monitoring device 30 also notifies the outside by sending an email or the like containing the alert information to the user depending on the status of the malfunction.

[0016] The user visually recognizes the alert information displayed on the display device, and also recognizes the alert information by receiving an e-mail or the like via the user terminal device 40. The user recognizes the alert information notified to the outside by the tire monitoring device 30, and can plan maintenance for the vehicle and tires.

[0017] 2 is a block diagram showing the functional configuration of the tire monitoring device 30. The sensor 10 includes an air pressure sensor 11 and a temperature sensor 12 disposed in the tire 1. The air pressure sensor 11 measures the tire air pressure. The temperature sensor 12 measures the tire temperature. The air pressure sensor 11 and the temperature sensor 12 are disposed, for example, in the air valve of the tire 1. The temperature sensor 12 may be disposed directly in the tire 1 to accurately measure the temperature of the tire 1.

[0018] The vehicle measurement device 20 accumulates measurement data of tire pressure and tire temperature measured by the sensors 10 and transmits the data to the tire monitoring device 30 via the communication network 8. The vehicle measurement device 20 transmits the stored measurement data to the tire monitoring device 30, for example, every few minutes to every tens of minutes. The time interval at which the vehicle measurement device 20 transmits the measurement data to the tire monitoring device 30 is not limited to every few minutes to every tens of minutes. The measurement data transmitted from the vehicle measurement device 20 to the tire monitoring device 30 also includes information on the mounting position of each measured tire 1 on the axle arrangement.

[0019] The tire monitoring device 30 includes a communication unit 31, an information acquisition unit 32, a temperature determination unit 33, an air pressure determination unit 34, a notification unit 35, a display unit 36, and a memory unit 37. Each unit in the tire monitoring device 30 can be realized in hardware terms by an electronic processing circuit or mechanical parts made up of electronic elements such as a computer CPU, or in software terms by a computer program, but the functional blocks realized by the cooperation of these are depicted here. Therefore, it will be understood by those skilled in the art that these functional blocks can be realized in various forms by combining hardware and software.

[0020] The communication unit 31 is connected to the communication network 8 via wireless or wired communication and communicates with the vehicle measurement device 20. The information acquisition unit 32 acquires the measurement data of tire pressure and tire temperature transmitted by the vehicle measurement device 20 via the communication unit 31. The measurement data acquired by the information acquisition unit 32 is assumed to be associated with the identification information of the vehicle 7. The information acquisition unit 32 stores the acquired measurement data of tire pressure and tire temperature in the memory unit 37. The information acquisition unit 32 also outputs the acquired tire temperature information to the temperature determination unit 33.

[0021] The storage unit 37 is a storage device configured by, for example, an SSD (Solid State Drive), a hard disk, a CD-ROM, a DVD, etc. The storage unit 37 stores vehicle management information 37a, sensor measurement data 37b, and determination result information 37c.

[0022] The vehicle management information 37a is information relating to a plurality of vehicles 7 whose operation is managed by, for example, a transport company, and includes the name of the vehicle 7, identification information of the vehicle 7 assigned to each vehicle, axle arrangement information, etc. The axle arrangement information includes information on the mounting position of tires on the axle arrangement.

[0023] The sensor measurement data 37b is measurement data of tire pressure and tire temperature acquired by the information acquisition unit 32 for each vehicle 7 included in the vehicle management information 37a. The sensor measurement data 37b includes information on the date and time when the tire pressure and tire temperature were measured. The determination result information 37c is the determination results by the temperature determination unit 33 and the air pressure determination unit 34 stored in the storage unit 37.

[0024] The temperature determination unit 33 calculates the amount of temperature change of each tire on each vehicle 7 based on the measurement data acquired by the information acquisition unit 32 within a predetermined period. For each predetermined period (for example, one day), the temperature determination unit 33 obtains the maximum temperature of each tire 1 by performing a comparison operation on the measurement data within the period, and sets this as the representative temperature Tr for that period. The temperature determination unit 33 calculates the amount of temperature change Tc based on the transition of the representative temperature Tr of each tire 1 for each predetermined period. For example, if the predetermined period is one day, the temperature determination unit 33 calculates the difference between the representative temperature Tr of each day and the representative temperature Tr of the previous day, and sets this as the amount of temperature change Tc.

[0025] The temperature determination unit 33 determines, for each vehicle 7, a difference value ΔTc between the temperature change amount of one tire 1 with the largest temperature change amount and the temperature change amount of the other tires 1, and determines whether the difference value ΔTc is larger than a predetermined threshold value Ts. The temperature determination unit 33, for example, calculates an average value of the temperature change amounts of the other tires 1, and calculates the difference between the temperature change amount of one tire 1 with the largest temperature change amount and the average value of the temperature change amounts of the other tires 1, to obtain the difference value ΔTc. After determining the one tire 1 with the largest temperature change amount, the temperature determination unit 33 may, for example, exclude the tire 1 with the largest temperature change amount and the tire 1 with the smallest temperature change amount from among the other tires 1, and then determine the average value of the temperature change amounts of the other tires 1.

[0026] The temperature determination unit 33 determines whether a tire 1 with an abnormally large temperature change exists by determining whether the difference value ΔTc between the temperature change of one tire 1 with the largest temperature change and the temperature change of another tire 1 is greater than a predetermined threshold value Ts.

[0027] If the temperature determination unit 33 determines that the difference value ΔTc is greater than the predetermined threshold Ts, it outputs the determination result to the storage unit 37 and stores it as determination result information 37c. The determination result information 37c includes information on the difference value ΔTc, identification information of the corresponding vehicle 7, information on the mounting position on the axle arrangement of the tire 1 with the largest amount of temperature change, date and time information, etc. Furthermore, if the temperature determination unit 33 determines that the difference value ΔTc is greater than the predetermined threshold Ts, it outputs the determination result to the air pressure determination unit 34.

[0028] When the temperature determination unit 33 determines that the difference value ΔTc is greater than the predetermined threshold Ts, the air pressure determination unit 34 determines whether the malfunction is caused by the vehicle side or the tire side based on the air pressure measurement data. The air pressure determination unit 34 reads out, from the sensor measurement data 37b in the memory unit 37, the air pressure data of the tire 1 that has the largest amount of temperature change during the period in which it was determined that the difference value ΔTc is greater than the predetermined threshold Ts.

[0029] The air pressure determination unit 34 obtains the minimum air pressure of the tire 1 during the period in which it is determined that the difference value ΔTc is greater than the predetermined threshold value Ts by performing a comparison operation on the measurement data during that period, and sets this as the representative air pressure Pr for that period. The air pressure determination unit 34 may also obtain the air pressure of the tire 1 that has cooled down when the vehicle is not running, for example, the air pressure of the tire 1 immediately after the engine of the vehicle 7 is started, for each predetermined period, and set this as the representative air pressure Pr. The air pressure of the cooled tire 1 is the air pressure of the tire 1 when the vehicle is stopped. Specific examples of the air pressure of the cooled tire 1 include the air pressure of the tire 1 before running when the engine is started, and the air pressure of the tire after the vehicle has been stopped for a predetermined time.

[0030] The air pressure determination unit 34 determines that the malfunction is caused by the vehicle when the representative air pressure Pr of the tire 1 is greater than a predetermined threshold Ps. The air pressure determination unit 34 determines that the malfunction is caused by the tire when the representative air pressure Pr of the tire 1 is less than the predetermined threshold Ps. Here, the air pressure determination unit 34 sets the predetermined threshold Ps to the lower limit of a specified range of tire air pressure recommended when mounting the tire 1 on the vehicle 7. Furthermore, the air pressure determination unit 34 may set the predetermined threshold Ps to a value lower than the lower limit of a specified range of tire air pressure recommended when mounting the tire 1 on the vehicle 7, depending on a user setting.

[0031] Generally, when the tire pressure drops significantly, the rigidity of the tire 1 decreases, which increases mechanical vibrations within the tire 1 while the vehicle is running, causing the tire temperature to rise. For this reason, the air pressure determination unit 34 determines that the problem is caused by the tire 1 when the representative air pressure Pr is equal to or lower than the threshold value Ps.

[0032] If the representative air pressure Pr is greater than the threshold value Ps, the air pressure determination unit 34 determines that the problem is not caused by the tire but by a mechanical component or the like on the vehicle. The mechanical component on the vehicle is, for example, a bearing or brake component disposed in the hub. When friction increases in the mechanical component or the like on the vehicle, heat generated in the tire 1 may be transferred to the tire, causing an increase in the temperature change of the tire 1.

[0033] The pressure determination unit 34 outputs the result of the comparison between the representative air pressure Pr of the tire 1 and the threshold value Ps to the storage unit 37, and stores the result as determination result information 37c in the storage unit 37. The determination result information 37c is added with information corresponding to the determination result by the temperature determination unit 33, and indicating whether the defect in the tire 1 is occurring on the vehicle side or the tire side.

[0034] The notification unit 35 reads the determination result information 37c from the storage unit 37 and generates alert information including the amount of temperature change of the tire 1, information about the cause of the occurrence, identification information of the corresponding vehicle 7, information about the mounting position of the tire 1 on the axle arrangement, date and time information, etc. The information about the cause of the occurrence includes information indicating whether the malfunction is caused by the vehicle side or the tire side. The notification unit 35 notifies the generated alert information to an external device.

[0035] The notification unit 35 may output the alert information to the display unit 36 ​​of the tire monitoring device 30, display it on the display unit 36, and notify the user. The display unit 36 ​​includes a display device such as a liquid crystal display, and displays the alert information input from the notification unit 35 on the display device.

[0036] The display unit 36 ​​may read the measurement data of the tire temperature and tire pressure of the vehicle 7 corresponding to the alert information from the sensor measurement data 37b in the storage unit 37, and display the tire temperature and tire pressure in a time series graph arranged vertically on the display device. The display unit 36 ​​displays the changes in tire temperature and tire pressure over a predetermined period (several months), for example, on the display device, thereby making the user aware of the changes in tire temperature and tire pressure.

[0037] The notification unit 35 may generate an email containing the generated alert information and send it to an email address owned by the user. The user can receive the email sent by the notification unit 35 and learn of the alert information using an email sending / receiving application or the like in the tire monitoring device 30 and the user terminal device 40. The user terminal device 40 is, for example, an information processing device such as a smartphone or a personal computer.

[0038] When the tire pressure determination unit 34 determines that a malfunction has occurred on the vehicle side, the notification unit 35 may generate alert information including an instruction to stop the vehicle 7 and notify the driver of the vehicle 7, a user who manages the vehicle operation, etc.

[0039] Next, the operation of the tire monitoring system 100 will be described. FIG. 3 is a flowchart showing the procedure for the malfunction determination process performed by the tire monitoring system 100. An example of the determination process corresponding to a vehicle selected in advance by the user will be described below, but the same process can be performed sequentially for multiple vehicles under operational management. The information acquisition unit 32 of the tire monitoring device 30 acquires measurement data of tire pressure and tire temperature from the vehicle measurement device 20 (S1). The information acquisition unit 32 outputs the acquired measurement data of tire pressure and tire temperature to the memory unit 37 for storage.

[0040] The temperature determination unit 33 calculates the temperature change amount Tc of each tire 1 (S2). In step S2, the temperature determination unit 33 acquires the maximum temperature value of each tire 1 for each predetermined period and sets it as a representative temperature, and calculates the temperature change amount Tc based on the transition of the representative temperature of each tire 1.

[0041] The temperature determination unit 33 calculates (S3) a difference value ΔTc between the temperature change amount of the one tire 1 with the largest temperature change amount and the temperature change amount of the other tires 1. In step S3, the temperature determination unit 33, for example, calculates an average value of the temperature change amounts of the other tires 1, and calculates the difference between the temperature change amount of the one tire 1 with the largest temperature change amount and the average value of the temperature change amounts of the other tires 1, to obtain the difference value ΔTc.

[0042] The temperature determination unit 33 determines whether the difference value ΔTc is greater than a predetermined threshold value Ts (S4). If it is determined that the difference value ΔTc is greater than the threshold value Ts in step S4 (S4: NO), the process ends. If it is determined that the difference value ΔTc is greater than the threshold value Ts in step S4 (S4: YES), the air pressure determination unit 34 reads and acquires the tire air pressure data of the sensor measurement data 37b for the tire 1 with the largest amount of temperature change from the storage unit 37 (S5).

[0043] The air pressure determination unit 34 determines the minimum value of the air pressure of the tire 1 during the period in which it is determined that the difference value ΔTc is greater than the threshold value Ts, and calculates this as the representative air pressure Pr (S6). The air pressure determination unit 34 determines whether the representative air pressure Pr is greater than the threshold value Ps (S7). If it is determined that the representative air pressure Pr is not greater than the threshold value Ps in step S7 (S7: NO), the air pressure determination unit 34 determines that the cause of the malfunction in the tire 1 is related to the tire itself (S8).

[0044] In step S7, if it is determined that the representative air pressure Pr is greater than the threshold value Ps (S7: YES), the air pressure determination unit 34 determines that the cause of the problem in the tire 1 is related to the vehicle (S9).

[0045] The tire pressure determination unit 34 outputs the determination results of steps S8 and S9 to the storage unit 37, where they are stored as determination result information 37c (S10), and the process ends.

[0046] Fig. 4 is a graph showing an example of tire temperature when a tire malfunction occurs, and Fig. 5 is a graph showing an example of tire pressure when the cause of the malfunction is determined to be due to the vehicle. In Figs. 4 and 5, the horizontal axis represents time, and the vertical axis represents tire temperature and tire pressure. The examples shown in Figs. 4 and 5 relate to a truck vehicle with one axle at the front and one at the rear of the vehicle, with two tires A11 and A12 on the front axle and four tires A21, A22, A23, and A24 on the rear axle.

[0047] The temperature of each tire shown in Figure 4 represents the maximum tire temperature measured in one day, with one day being the specified period. In Figure 4, the temperature of the six tires did not reach the high temperature usage limit of 90°C from December 11th to December 25th, and the tires themselves were not experiencing any problems due to tire temperature. In Figure 4, the graph for tire A12 largely overlaps with the graph for tire A11.

[0048] In Figure 4, the temperature change Tc of tire A23 from December 14 to December 15 was approximately 7°C, the largest temperature change of any tire mounted on the vehicle. The average temperature change of the other tires (A11, A12, A21, etc.) was approximately 2°C.

[0049] The temperature determination unit 33 calculates the difference value ΔTc between the temperature change amount of tire A23, which has the largest temperature change amount, and the temperature change amounts (average values) of the other tires to be 5° C. If the predetermined threshold value Ts is set to 4° C., the temperature determination unit 33 will determine that the difference value ΔTc (= 5° C.) is greater than the predetermined threshold value Ts (= 4° C.).

[0050] When the temperature determination unit 33 determines that the difference value ΔTc is greater than the predetermined threshold value Ts, the air pressure determination unit 34 determines whether the malfunction is caused by the vehicle side or the tire side based on the air pressure measurement data.

[0051] The tire pressures shown in Figure 5 represent a representative tire pressure Pr, which is the minimum tire pressure measured over a predetermined period of one day. In Figure 5, the graph for tire A22 roughly overlaps with the graph for tire A21. In Figure 5, the representative tire pressure Pr for tire A23 on December 15 is 525 kPa. The predetermined threshold value Ps is set to 500 kPa, and the tire pressure determination unit 34 determines that the representative tire pressure Pr (= 525 kPa) for tire A23 on December 15 is greater than the predetermined threshold value Ps (= 500 kPa), and therefore determines that the problem with tire A23 is caused by the vehicle.

[0052] Furthermore, the temperature change Tc of tire A23 from December 17th to December 18th was approximately 26°C, and the difference ΔTc from the average temperature change of the other tires (approximately 7°C) was approximately 19°C. If the predetermined threshold Ts is set to 4°C, the temperature determination unit 33 determines that the difference ΔTc (=19°C) is greater than the predetermined threshold Ts (=4°C).

[0053] The air pressure determination unit 34 determines that the representative air pressure Pr (=518 kPa) of tire A23 on December 18th is greater than the predetermined threshold value Ps (=500 kPa), and determines that the problem in tire A23 is caused by the vehicle.

[0054] In the example shown in Figures 4 and 5, the air pressure determination unit 34 may determine that the malfunction in tire A23 was caused by a problem on the vehicle side on two occasions, on December 15th and December 18th. In the example shown in Figures 4 and 5, when the vehicle was actually inspected on December 21st, it was found that there was a malfunction in a mechanical part on the vehicle side near tire A23, and that the heat generated by this mechanical part had caused the temperature change in tire A23 to be larger than that of the other tires. Furthermore, after the malfunction in the mechanical part on the vehicle side was repaired on December 21st, the temperature change in tire A23 thereafter became equivalent to that of the other tires.

[0055] If tire temperature is used as a criterion for fault monitoring, when the tire temperature reaches a high temperature (e.g., 80°C or higher), it will be determined whether the fault is on the vehicle side or the tire side depending on whether the tire pressure is normal. Tire temperatures change with the seasons, and in Japan, it is expected that tire temperatures may reach high temperatures if a tire fault occurs during the hot summer months.

[0056] On the other hand, in winter, when the temperature is low, tire temperatures do not reach high levels, but tire problems may occur, and a monitoring method that uses tire temperature as a criterion for judgment may miss the problem. In the examples shown in Figures 4 and 5, by determining a problem based on the temperature change Tc of tire 1, it is possible to detect the occurrence of a problem even when the temperature is low and the tire temperature does not reach a high level. Outside of winter, the monitoring method that uses tire temperature as a criterion, as described in Japanese Patent Application No. 2023-181369, may also be used.

[0057] The tire monitoring system 100 acquires measurement data from air pressure sensors 11 and temperature sensors 12 provided on multiple tires 1 mounted on a vehicle 7 using an information acquisition unit 32. The temperature determination unit 33 calculates the temperature change Tc of each tire 1 based on the measurement data acquired by the information acquisition unit 32 and determines whether the difference ΔTc between the temperature change of at least one tire 1 with the largest temperature change and the temperature change of the other tires is greater than a predetermined threshold Ts. If the temperature determination unit 33 determines that the difference ΔTc is greater than the predetermined threshold Ts, the air pressure determination unit 34 determines whether a problem has occurred on the vehicle side or on the tire side based on the air pressure measurement data. This allows the tire monitoring system 100 to determine the cause of the problem in the tire 1 and improve maintainability.

[0058] The temperature determination unit 33 obtains the maximum temperature of the tire 1 at every predetermined period, sets the representative temperature Tr, and calculates the temperature change Tc based on the transition of the representative temperature Tr. This allows the tire monitoring system 100 to determine whether a malfunction has occurred based on the temperature change Tc of the tire 1 when the temperature rises due to vehicle travel.

[0059] The air pressure determination unit 34 obtains the minimum air pressure of the tire 1 at predetermined intervals as a representative air pressure Pr, and determines that a malfunction has occurred on the vehicle side if the representative air pressure Pr is greater than a predetermined threshold value Ps. This allows the tire monitoring system 100 to determine whether a malfunction has occurred based on the minimum air pressure of the tire 1 over a predetermined period.

[0060] The air pressure determination unit 34 obtains the tire pressure when the vehicle is not running and is cooled (when cooled), for example, immediately after the engine of the vehicle 7 is started, and sets this as the representative air pressure Pr, and determines that a malfunction has occurred on the vehicle side if the representative air pressure Pr is greater than a predetermined threshold value Ps. This allows the tire monitoring system 100 to determine whether a malfunction has occurred based on the air pressure of the tire 1 when cooled, such as immediately after the engine of the vehicle 7 is started.

[0061] The tire monitoring system 100 further includes a notification unit 35 that notifies the outside of the result determined by the air pressure determination unit 34. This allows the tire monitoring system 100 to notify the user or the like of the determination result regarding the cause of the malfunction in the tire 1 mounted on the vehicle 7.

[0062] (Variation) 6 is a block diagram showing a functional configuration of a tire monitoring device 30 according to a modified example. When the tire monitoring device 30 according to the modified example determines that a defect in a tire 1 is caused by an issue on the vehicle side, the tire monitoring device 30 stores maintenance cost information 37d, including information on costs required for maintenance of the vehicle 7, in a storage unit 37.

[0063] The maintenance cost information 37d may include, for example, a service fee for dispatching an inspection service vehicle when the vehicle 7 must be stopped, a towing fee, a vehicle repair fee, a fee for replacing the vehicle itself, etc. The maintenance cost information 37d may also include, for example, information on delay damages incurred by a transport company due to a delay in the transport of people or goods caused by a malfunctioning vehicle 7.

[0064] When it is determined that the defect in the tire 1 is caused by a factor on the vehicle side, the notification unit 35 reads out the maintenance cost information 37d from the storage unit 37, and notifies the alert information by adding evaluation information including information on the cost required for maintenance of the vehicle 7 to the alert information. The user can create a maintenance plan for the vehicle 7 based on the evaluation information including information on the cost required for maintenance that is added to the alert information notified by the notification unit 35.

[0065] The notification unit 35 may notify information tallying the number of times notifications have been sent to the outside for each predetermined period for multiple vehicles. The tire monitoring device 30 acquires measurement data for multiple vehicles 7 operated by, for example, a transportation company using the information acquisition unit 32, and determines whether the tire temperature difference value ΔTc for each vehicle 7 is greater than a predetermined threshold value Ts using the temperature determination unit 33. The air pressure determination unit 34 of the tire monitoring device 30 determines whether a problem has occurred on the vehicle side or the tire side for each vehicle 7, and stores the determination result in the memory unit 37 as determination result information 37c.

[0066] For example, the aggregation period is one year, and the predetermined period is one month, and the notification unit 35 calculates the number of times alert information was generated and notified to the outside for each vehicle each month, and generates tabular defect occurrence aggregation data that allows the number of notifications for one year to be listed by vehicle and month.By notifying the tire monitoring system 100 of the defect occurrence aggregation data to the outside, the tire monitoring system 100 can provide transportation companies and the like with information on defect conditions, such as vehicles with many defects and periods when defects are likely to occur.

[0067] In the above-described embodiment and modified examples, the predetermined threshold value Ts, the predetermined threshold value Ps, and various predetermined periods have been exemplified, but the threshold values ​​and predetermined periods are not limited to these, and the values ​​may be set based on past cases in which the tire 1 has had a defect or on a detailed design analysis of the tire 1. Furthermore, in the present embodiment, an example has been shown in which there is a defect in one tire or in one location on the vehicle, but it is also possible to determine if there are defects in two or more tires or in two or more locations.

[0068] Alternatively, the air pressure determination unit 34 may refer to the current tire pressure of a tire 1 whose tire temperature difference value ΔTc is greater than a predetermined threshold value Ts, and determine whether a malfunction has occurred on the vehicle side or on the tire side depending on whether the current tire pressure is greater than the predetermined threshold value Ps. The air pressure determination unit 34 determines that a malfunction has occurred on the tire side when the current tire pressure is lower than the predetermined threshold value Ps. Even if the representative air pressure Pr, which is the tire pressure when cooled, is higher than the predetermined threshold value Ps as described in the embodiment, and it has been determined that a malfunction has occurred on the vehicle side, the air pressure determination unit 34 can re-determine that a malfunction has occurred on the tire side when the current tire pressure is lower than the predetermined threshold value Ps.

[0069] The transportation business is not limited to a business that operates and manages trucks for transportation, but also includes, for example, a taxi business, etc. Furthermore, the vehicle 7 is not limited to a truck vehicle or a taxi vehicle, but also includes a rental vehicle from a rental business, a shared vehicle provided by a vehicle sharing business, a private car purchased by an ordinary household, etc.

[0070] The present invention has been described above based on the embodiments. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications and changes are possible within the scope of the claims of the present invention, and that such modifications and changes also fall within the scope of the claims of the present invention. Therefore, the descriptions and drawings in this specification should be treated as illustrative rather than restrictive.

[0071] When the technical ideas embodied in the above-described embodiments and modified examples are generalized, it can be said that the technical ideas described in the following items are included.

[0072] The first item is a tire monitoring system that includes an information acquisition unit that acquires measurement data from air pressure sensors and temperature sensors installed in multiple tires mounted on a vehicle; a temperature determination unit that calculates the temperature change amount of each tire based on the measurement data acquired by the information acquisition unit and determines whether the difference value between the temperature change amount of at least one tire with the largest temperature change amount and the temperature change amounts of the other tires is greater than a predetermined threshold; and an air pressure determination unit that, when the temperature determination unit determines that the difference value is greater than the predetermined threshold, determines whether a problem is occurring on the vehicle side or on the tire side based on the air pressure measurement data.

[0073] The second item is a tire monitoring system described in the first item, in which the air pressure determination unit obtains the minimum value of the tire air pressure at predetermined intervals and sets it as a representative air pressure, and if the representative air pressure is greater than a predetermined threshold value, determines that a malfunction has occurred on the vehicle side.

[0074] A third item is a tire monitoring system according to any one of the first and second items, wherein the air pressure determination unit determines whether a problem has occurred on the vehicle side or on the tire side by referring to the current tire air pressure of a tire whose difference value is greater than the predetermined threshold value.

[0075] A fourth item is a tire monitoring system described in any one of the first to third items, in which the temperature determination unit obtains the maximum tire temperature at each predetermined period and sets it as a representative temperature, and calculates the amount of temperature change based on changes in the representative temperature.

[0076] The fifth item is a tire monitoring system described in any one of the first to fourth items, in which the air pressure determination unit obtains the air pressure of the tire when cooled and sets it as a representative air pressure, and if the representative air pressure is greater than a predetermined threshold value, determines that a malfunction has occurred on the vehicle side.

[0077] A sixth item is the tire monitoring system according to any one of the first to fifth items, further comprising a notification unit that notifies an external party of the result determined by the air pressure determination unit.

[0078] Item 7 is a tire monitoring system described in item 6, in which the notification unit further notifies an external party of evaluation information including the cost required for vehicle maintenance if the air pressure determination unit determines that a malfunction has occurred on the vehicle side.

[0079] Item 8 is a tire monitoring system described in any one of items 6 to 7, in which the information acquisition unit acquires the measurement data from multiple vehicles operated and managed by a transportation company, the temperature determination unit determines whether the difference value is greater than a predetermined threshold for each vehicle, the air pressure determination unit determines whether a problem has occurred on the vehicle side or the tire side for each vehicle, and the notification unit notifies information tallying the number of notifications for each predetermined period for the multiple vehicles.

[0080] The ninth item is a tire monitoring method including an information acquisition step of acquiring measurement data from air pressure sensors and temperature sensors provided on multiple tires mounted on a vehicle; a temperature determination step of calculating the amount of temperature change for each tire based on the measurement data acquired by the information acquisition step and determining whether the difference between the amount of temperature change for at least one tire with the largest amount of temperature change and the amount of temperature change for the other tires is greater than a predetermined threshold; and an air pressure determination step of determining whether a problem has occurred on the vehicle side or on the tire side based on the air pressure measurement data if the temperature determination step determines that the difference value is greater than the predetermined threshold. [Explanation of symbols]

[0081] 1 tire, 7 vehicle, 11 air pressure sensor, 12 temperature sensor, 32 information acquisition unit, 33 temperature determination unit, 34 tire pressure determination unit, 35 notification unit, 100 Tire Monitoring System.

Claims

1. an information acquisition unit that acquires measurement data from air pressure sensors and temperature sensors provided in a plurality of tires mounted on a vehicle; a temperature determination unit that calculates the amount of temperature change for each tire based on the measurement data acquired by the information acquisition unit, and determines whether a difference value between the amount of temperature change for at least one tire with the largest amount of temperature change and the amount of temperature change for the other tires is greater than a predetermined threshold value; an air pressure determination unit that determines whether a problem has occurred on the vehicle side or on the tire side based on air pressure measurement data when the temperature determination unit determines that the difference value is greater than the predetermined threshold value; and A tire monitoring system comprising:

2. The tire monitoring system of claim 1, wherein the air pressure determination unit obtains the minimum value of the tire air pressure at predetermined intervals and sets it as a representative air pressure, and if the representative air pressure is greater than a predetermined threshold, determines that a malfunction has occurred on the vehicle side.

3. 2. The tire monitoring system according to claim 1, wherein the air pressure determination unit determines whether a problem has occurred on the vehicle side or on the tire side by referring to the current tire air pressure of a tire whose difference value is greater than the predetermined threshold value.

4. The tire monitoring system according to any one of claims 1 to 3, wherein the temperature determination unit obtains the maximum tire temperature at each predetermined period and sets it as a representative temperature, and calculates the temperature change amount based on changes in the representative temperature.

5. The tire monitoring system of claim 1, wherein the air pressure determination unit obtains the air pressure of the tire when cooled and uses it as a representative air pressure, and if the representative air pressure is greater than a predetermined threshold, determines that a malfunction has occurred on the vehicle side.

6. The tire monitoring system according to claim 1 , further comprising a notification unit that notifies an external device of the result determined by the air pressure determination unit.

7. The tire monitoring system according to claim 6, wherein the notification unit further notifies an external party of evaluation information including the cost required for vehicle maintenance when the air pressure determination unit determines that a malfunction has occurred on the vehicle side.

8. the information acquisition unit acquires the measurement data of a plurality of vehicles operated and managed by a transportation company, the temperature determination unit determines whether the difference value is greater than a predetermined threshold value for each vehicle; the air pressure determination unit determines whether a problem occurs on the vehicle side or on the tire side for each vehicle, The tire monitoring system according to claim 6 , wherein the notification unit notifies information that is a total of the number of notifications per predetermined period for the plurality of vehicles.

9. an information acquisition step of acquiring measurement data from air pressure sensors and temperature sensors provided in a plurality of tires mounted on the vehicle; a temperature determination step of calculating a temperature change amount for each tire based on the measurement data acquired in the information acquisition step, and determining whether a difference value between the temperature change amount of at least one tire having the largest temperature change amount and the temperature change amount of the other tires is larger than a predetermined threshold value; an air pressure determination step of determining whether a problem has occurred on the vehicle side or on the tire side based on air pressure measurement data when it is determined in the temperature determination step that the difference value is greater than the predetermined threshold value; A tire monitoring method comprising:

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