Tire condition management device, program, and tire condition management method

Abstract

A tire condition management device, program, and tire condition management method are provided that can manage the condition of a tire, including the remaining tread depth, based on the internal temperature of the tire. [Solution] A tire condition management device (10) for managing the condition of a tire mounted on a vehicle (20), including at least the remaining tread depth, comprising: an acquisition unit (131) that acquires input data including time-series data of the internal tire temperature and the vehicle speed detected by a detection device (70) mounted on the vehicle; a calculation unit (132) that calculates a heat generation coefficient based on the input data using a model in which the heating component of the rate of increase in the internal tire temperature is calculated by multiplying the proportional component of the vehicle speed by the heat generation coefficient; and a determination unit (133) that extracts a first component originating from the vehicle load and a second component originating from tire wear from the fluctuations in the time-series data of the calculated heat generation coefficient, and determines the condition of the remaining tread depth based on the second component.

Description

Technical Field

[0001] The present disclosure relates to a tire condition management device, a program, and a tire condition management method.

Background Art

[0002] Conventionally, methods for managing the conditions of tires of a vehicle during travel have been proposed. Also, the vehicle conditions (for example, presence or absence of loading) have been estimated from the conditions of the tires. Here, in order to evaluate the durability of a tire, it is important to accurately predict the temperature of the tire during travel. For example, Patent Document 1 discloses a tire temperature prediction method that calculates the predicted heat generation amount for each element of a tire model composed of a plurality of elements based on load information and speed information during tire use, and predicts the temperature distribution of the tire by a computer based on the calculated predicted heat generation amount.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, an example of the condition of a tire to be managed is the remaining groove of the tire. When the remaining groove of the tire becomes smaller than a predetermined value, tire replacement is required. However, the wear amount of the tire is affected by the content of driving. For example, a vehicle with many sudden starts or sudden brakes may wear significantly. Therefore, even if replaced at the same time, the remaining grooves of the tires may differ depending on each vehicle. For example, a number of techniques for measuring or estimating the remaining grooves of commercial vehicle tires have been proposed, but many of them require expensive devices. Therefore, a method for easily determining the condition of the remaining grooves of a tire based on the temperature inside the tire measured in a general vehicle, etc., is required.

[0005] In view of these circumstances, the purpose of this disclosure is to provide a tire condition management device, program, and tire condition management method that can manage the condition of a tire, including the remaining tread depth, based on the internal temperature of the tire. [Means for solving the problem]

[0006] (1) A tire condition management device according to one embodiment of the present disclosure, A tire condition management device that manages the condition of tires mounted on a vehicle, including at least the remaining tread depth, An acquisition unit that acquires input data including time-series data of the tire temperature and the vehicle speed, respectively, detected by a detection device mounted on the vehicle, A calculation unit that calculates the heat generation coefficient based on the input data, using a model in which the heating component of the rate of increase in the temperature inside the tire is calculated by multiplying the proportional component of the vehicle's speed by the heat generation coefficient, The system includes a determination unit that extracts a first component, represented by a high-frequency curve originating from the vehicle load, and a second component, represented by an envelope, originating from tire wear, from the time-series data of the calculated heat generation coefficient, and determines the state of the remaining tread based on the second component. This configuration allows for the management of the tire's condition, including the remaining tread depth, based on the internal tire temperature.

[0007] (2) As one embodiment of the present disclosure, in (1), The condition of the remaining tread depth determined by the determination unit includes at least one of a first condition in which the tire does not need to be replaced, a third condition in which the tire needs to be replaced, and a second condition which is intermediate between the first and third conditions and indicates that the tire is approaching the third condition. This configuration makes it easier for vehicle managers and others to determine when it's time to replace the tires.

[0008] (3) As one embodiment of the present disclosure, in (2), The determination unit sets a reference value in advance based on the maximum value in the time-series data of the heat generation coefficient since the tire was replaced, and determines that the third state is occurring when the calculated heat generation coefficient falls below the reference value. This configuration allows for accurate determination of tire tread depth, excluding the influence of driving conditions.

[0009] (4) In one embodiment of the present disclosure, in any of (1) to (3), The calculation unit identifies the time when the vehicle is stopped and immediately after it starts moving based on the vehicle's speed, and calculates the heat generation coefficient based on the input data excluding the identified time. This configuration allows for accurate determination of tire tread depth, excluding the effects of road surface temperature and weather conditions.

[0010] (5) In one embodiment of the present disclosure, in any of (1) to (4), The determination unit determines whether or not the vehicle is loaded based on the first component. This configuration allows the vehicle's condition to be managed based on the temperature inside the tires.

[0011] (6) As one embodiment of the present disclosure, in (5), The determination unit determines whether or not the vehicle is loaded using the ratio of the first component of the front wheels to the first component of the rear wheels of the vehicle. This configuration allows for accurate determination of whether or not a vehicle is loaded.

[0012] (7) In one embodiment of the present disclosure, in any of (1) to (6), The determination unit generates a histogram for a specific period from the time-series data of the heat generation coefficient, and determines whether the tire is a front wheel or a rear wheel based on the difference between the highest and lowest values ​​extracted from the histogram. This configuration allows for accurate determination of whether a wheel is a front or rear wheel based on its heat generation coefficient.

[0013] (8) In one embodiment of the present disclosure, in any of (1) to (7), The determination unit generates a histogram for a specific period from the time-series data of the heat generation coefficient, and determines whether the tire is the inner rear wheel or the outer rear wheel based on the difference between the upper and lower values ​​extracted from the histogram. This configuration allows for accurate determination of the inner and outer rear wheels based on their heat generation coefficients.

[0014] (9) A program according to one embodiment of the present disclosure is A tire condition management device that manages the condition of tires mounted on a vehicle, including at least the remaining tread depth, The system acquires input data including time-series data of the tire temperature and the vehicle's speed, respectively, as detected by a detection device mounted on the vehicle. Using a model in which the heating component of the rate of increase in the temperature inside the tire is calculated by multiplying the proportional component of the vehicle's speed by the heat generation coefficient, the heat generation coefficient is calculated based on the input data, From the time-series data of the calculated heat generation coefficient, a first component represented by a high-frequency curve originating from the vehicle load and a second component represented by an envelope originating from the tire wear are extracted, and the state of the remaining tread is determined based on the second component. This configuration allows for the management of the tire's condition, including the remaining tread depth, based on the internal tire temperature.

[0015] (10) A tire condition management method according to one embodiment of the present disclosure is A tire condition management method performed by a tire condition management device that manages the condition of a tire mounted on a vehicle, including at least the remaining tread depth, The system acquires input data including time-series data of the tire temperature and the vehicle's speed, respectively, as detected by a detection device mounted on the vehicle. Using a model in which the heating component of the rate of increase in the temperature inside the tire is calculated by multiplying the proportional component of the vehicle's speed by the heat generation coefficient, the heat generation coefficient is calculated based on the input data, From the time-series data of the calculated heat generation coefficient, extract a first component represented by a high-frequency curve derived from the load of the vehicle and a second component represented by an envelope curve derived from the wear of the tire, and determine the state of the remaining groove based on the second component. With this configuration, it is possible to manage the state of a tire including remaining grooves based on the tire internal temperature.

Advantages of the Invention

[0016] According to the present disclosure, it is possible to provide a tire state management device, a program, and a tire state management method capable of managing the state of a tire including remaining grooves based on the tire internal temperature.

Brief Description of the Drawings

[0017] [Figure 1] FIG. 1 is a diagram showing a configuration example of a tire state management system including a tire state management device according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is another diagram showing a configuration example of the tire state management system of FIG. 1. [Figure 3] FIG. 3 is a diagram for explaining the calculation of the heat generation coefficient. [Figure 4] FIG. 4 is a diagram for explaining a first component and a second component of time-series data of the heat generation coefficient. [Figure 5] FIG. 5 is an example of a flowchart showing the processing of a tire state management method according to an embodiment of the present disclosure. [Figure 6] FIG. 6 is a diagram for explaining the determination of the front wheels and rear wheels based on the heat generation coefficient.

Modes for Carrying Out the Invention

[0018] Hereinafter, a tire state management device 10 (see FIG. 1), a program, and a tire state management method according to an embodiment of the present disclosure will be described with reference to the drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals. In the description of the present embodiment, the description of the same or corresponding parts will be omitted or simplified as appropriate.

[0019] Figures 1 and 2 show examples of the configuration of a tire condition management system. The tire condition management system includes a tire condition management device 10. Figure 1 is a block diagram showing an example of the internal configuration of the tire condition management device 10 and an example of the configuration of the device mounted on the vehicle 20. Figure 2 shows the overall configuration of the tire condition management system.

[0020] The tire condition management device 10 manages the condition of the tires 30 mounted on the vehicle 20. The condition of the tires 30 includes at least the condition of the remaining tread depth. When the remaining tread depth of the tires 30 becomes smaller than a predetermined value (for example, 3 mm), in other words, when the tires 30 wear down beyond a predetermined amount, tire replacement becomes necessary. However, the amount of wear on the tires 30 is affected by the driving conditions, and for example, vehicles 20 that frequently accelerate or brake suddenly may experience significant wear. Therefore, even if replaced at the same time, the remaining tread depth of the tires 30 may differ depending on the vehicle 20. Furthermore, conventional technologies for measuring or estimating the remaining tread depth of the tires 30 often require expensive devices. The tire condition management device 10 according to this embodiment easily determines the condition of the remaining tread depth of the tires 30 based on the internal temperature of the tires 30 (tire internal temperature) measured in a typical vehicle 20, using the configuration described below. The tire condition management device 10 may display the determination result, such as whether tire replacement is necessary or unnecessary, on a display unit so that, for example, the manager of the vehicle 20 can decide whether to replace the tires 30.

[0021] In this embodiment, the tire condition management device 10 further determines whether the vehicle 20 is loaded or not. The determination of whether the vehicle 20 is loaded or not can be made by determining one of two states: either it is loaded to nearly its maximum load capacity or it is loaded to nearly zero (empty).

[0022] Here, the vehicle 20 may be, for example, a passenger car, a truck, a bus, or a construction vehicle, and is not limited to a specific type of mobile body. In this embodiment, the vehicle 20 is described as a truck that transports cargo. Also, in order to avoid duplication of illustrations in Figures 1 and 2, only one vehicle 20 is shown, but the load determination system may be configured to include multiple vehicles 20.

[0023] The tire condition management device 10 comprises a communication unit 11, a storage unit 12, and a control unit 13. The control unit 13 comprises an acquisition unit 131, a calculation unit 132, a determination unit 133, and an output unit 134. The tire condition management device 10 may be, for example, a computer as its hardware configuration. The computer may be a server computer or a portable computer such as a laptop or tablet. Details of the components of the tire condition management device 10 will be described later. In this embodiment, the tire condition management device 10 is a computer in a management facility that manages the condition of the vehicle 20 (a truck that transports cargo) and the tires 30. The management facility may be, for example, the maintenance department of a transportation company that owns the vehicle 20, or for example, a tire shop that undertakes maintenance of the tires 30 of the vehicle 20.

[0024] Here, the tire condition management device 10 is not a single device, but may consist of multiple devices located in multiple locations that can send and receive data from each other via the network 40. In other words, multiple devices connected by the network 40 may function as the tire condition management device 10 shown in Figure 1. Therefore, for example, the tire condition management device 10 may consist of a single computer as its hardware configuration, or it may consist of multiple computers connected by the network 40. When it consists of multiple computers, the storage unit 12 may be a shared memory that can be accessed by each computer.

[0025] The tire condition management device 10 may constitute a tire condition management system together with devices mounted on a vehicle 20 connected via a network 40 (a detection device 70 and an in-vehicle communication device 80). The network 40 is, for example, the Internet. The network 40 may also be configured to include, for example, a LAN (Local Area Network) in part. Here, the tire condition management system may further include a terminal device 50 used by an administrator who manages the vehicle 20. The terminal device 50 is, for example, a general-purpose mobile terminal such as a smartphone or tablet, but is not limited to these. The terminal device 50 may function as a display unit that displays judgment results output from the tire condition management device 10. The tire condition management system may also include a storage device 90 (a cloud-based storage device 90) located on the network 40 as viewed from the tire condition management device 10 and the devices mounted on the vehicle 20. In this embodiment, the storage device 90 includes a database that stores data detected by the detection device 70 mounted on the vehicle 20 as time-series data, linked to the vehicle 20 or tire 30 that is the target of detection. Furthermore, in this embodiment, the tire condition management device 10 obtains necessary information from the database via the network 40. The database may also store attribute data such as the type of tire 30 and its mounting position.

[0026] In this embodiment, the vehicle 20 includes a detection device 70 and an in-vehicle communication device 80. The detection device 70 is a device or in-vehicle system equipped with sensors that generates information regarding the state of the tires 30. In this embodiment, the detection device 70 is configured to include a tire pressure monitoring system (TPMS). The detection device 70 may also include a device that detects the ambient temperature in the environment in which the tires 30 are used. The ambient temperature may be detected by the tire pressure monitoring system and another device (e.g., an ambient temperature gauge), or by the tire pressure monitoring system.

[0027] The tire pressure monitoring system monitors the pressure (internal pressure) and temperature (internal tire temperature) of the tire 30 mounted on the vehicle 20. The tire pressure monitoring system may be configured to include, for example, a sensor installed inside the tire 30, a processor that calculates and outputs the pressure of the tire 30 based on the sensor's detected values, and a memory that stores the sensor's detected values. The sensor may include a pressure sensor and a temperature sensor. The temperature sensor may include a sensor installed inside the tire 30 to detect the internal tire temperature, as well as a sensor installed on the outer surface of the tire 30 to detect the ambient temperature.

[0028] Furthermore, the detection device 70 includes a GPS (Global Positioning System) device or a speed sensor. For example, a car navigation system installed in the vehicle 20 may be used as the GPS device or speed sensor.

[0029] The in-vehicle communication device 80 is a device that outputs data detected by the detection device 70. The in-vehicle communication device 80 may be, for example, a dedicated communication device, but it may also be implemented by the communication function of a digital tachograph mounted on the vehicle 20. The information output from the in-vehicle communication device 80 is stored in the database of the storage device 90 on the cloud. In this embodiment, the in-vehicle communication device 80 outputs information on at least the tire temperature, the speed of the vehicle 20, and the ambient temperature, and this information is stored in the database of the storage device 90 on the cloud. Here, the speed of the vehicle 20 may be detected directly by the detection device 70, but it can also be calculated from the location information of the vehicle 20 obtained by the GPS device. In addition, the ambient temperature may be obtained from a weather information service provider via the network 40 instead of being detected by the detection device 70.

[0030] The components of the tire condition management device 10 are described below in detail. The communication unit 11 is composed of one or more communication modules connected to the network 40. The communication unit 11 may include communication modules that support mobile communication standards such as 4G (4th Generation) and 5G (5th Generation). The communication unit 11 may also include communication modules that support wired or wireless LAN standards.

[0031] The storage unit 12 is one or more memories. The memories are, for example, semiconductor memories, magnetic memories, or optical memories, but are not limited to these and can be any type of memory. The storage unit 12 is, for example, built into the tire condition management device 10, but it can also be configured to be accessed externally by the tire condition management device 10 via any interface.

[0032] The storage unit 12 stores various data used in various calculations performed by the control unit 13. The storage unit 12 may also store the results and intermediate data of various calculations performed by the control unit 13.

[0033] In this embodiment, the storage unit 12 may temporarily store various information from the database of the storage device 90 on the cloud, which is acquired via the communication unit 11.

[0034] The control unit 13 is one or more processors. The processors are, for example, general-purpose processors or dedicated processors specialized for specific processing, but are not limited to these and can be any processor. The control unit 13 controls the overall operation of the tire condition management device 10.

[0035] Here, the tire condition management device 10 may have the following software configuration. One or more programs used to control the operation of the tire condition management device 10 are stored in the storage unit 12. When the programs stored in the storage unit 12 are read by the processor of the control unit 13, the control unit 13 is made to function as an acquisition unit 131, a calculation unit 132, a determination unit 133, and an output unit 134.

[0036] The acquisition unit 131 acquires input data including time-series data of the tire temperature and the vehicle speed detected by the detection device 70 mounted on the vehicle 20. In this embodiment, the input data also includes information on the ambient temperature.

[0037] The calculation unit 132 calculates the heat generation coefficient based on the input data, using a model in which the heating component of the rate of increase in tire temperature is calculated by multiplying the proportional component of the vehicle speed 20 by the heat generation coefficient. Here, the model used by the calculation unit 132 calculates the rate of increase in tire temperature (i.e., the change in tire temperature over time) by subtracting the "heat dissipation component" from the "heating component". If the tire temperature is "T" and the time is "t", the rate of increase in tire temperature can be expressed as "dT / dt". That is, a calculation model is used in which (dT / dt) = "heating component" - "heat dissipation component". The heating component is the component that mainly increases the tire temperature. The heat dissipation component is the component that mainly decreases the tire temperature. The units of the rate of increase in tire temperature, the heating component, and the heat dissipation component may be, for example, [℃ / min].

[0038] First, the heat dissipation component is calculated as (tire internal temperature - ambient temperature) × (heat dissipation coefficient at stop + vehicle speed × heat dissipation increment). (Tire internal temperature - ambient temperature) is the difference between the tire internal temperature and the ambient temperature. The heat dissipation coefficient at stop is a coefficient that indicates the amount of heat dissipated from the tire 30 when the vehicle 20 is stopped. (Vehicle speed × heat dissipation increment) is a coefficient that indicates the amount of heat dissipated from the tire 30 when the vehicle 20 is in motion. As the speed of the vehicle 20 increases, more wind hits the tire 30, resulting in greater heat dissipation. Therefore, the coefficient for when the vehicle 20 is in motion is determined by multiplying by the vehicle speed. Here, the heat dissipation coefficient at stop and the heat dissipation increment may be determined based on past experimental data. In this embodiment, the heat dissipation coefficient at stop and the heat dissipation increment obtained from experimental data are stored in a database. The calculation unit 132 can obtain the heat dissipation coefficient at stop and the heat dissipation increment when calculating the rate of increase of the tire internal temperature via the storage unit 12.

[0039] Furthermore, the heating component is generally related to various factors, and conventionally, complex calculations have been required. In the method disclosed herein, a heat generation coefficient is introduced, and the heating component is calculated as (proportional component of vehicle speed) × (heat generation coefficient). The proportional component of vehicle speed is a value obtained by dividing the speed of vehicle 20 by the reference speed (for example, 80 km / h). When the reference speed is 80 km / h, if the speed of vehicle 20 is 80 km / h, the proportional component of vehicle speed is "1", and if the speed of vehicle 20 is 40 km / h, the proportional component of vehicle speed is "0.5". The calculation unit 132 determines the heat generation coefficient so that the tire internal temperature calculated using the simulation (simulated value or calculated value) is as close as possible to the actually measured tire internal temperature (measured value). Figure 3 shows an example of comparing the simulated value and the measured value by changing the heat generation coefficient. For example, when the simulation is performed with a heat generation coefficient of 0, it deviates significantly from the measured value, but when the heat generation coefficient is set to 10, the simulated value approaches the measured value. The calculation unit 132 changes the heat generation coefficient and takes the value that minimizes the difference between the simulated value and the measured value (8.2 in the example of Figure 3) as the calculated heat generation coefficient (determined heat generation coefficient). Here, the calculation unit 132 determines the heat generation coefficient based on the time series data of the tire temperature and the vehicle 20 speed, but the heat generation coefficient may be determined at predetermined intervals (for example, from a few days to a few months). The data obtained by arranging the heat generation coefficients determined for each predetermined interval in time series will be referred to as "time series data of the heat generation coefficient" below.

[0040] Here, the calculation unit 132 can use known fitting methods as a method for determining the heat generation coefficient. For example, the simulation value may be assigned to the x-axis of a two-dimensional coordinate system and the measured value to the y-axis, and the heat generation coefficient such that y=x can be obtained with the minimum information. Alternatively, assuming a linear change, the heat generation coefficient may be determined by identifying a straight line in the distribution corresponding the simulation value and the measured value, for example, using the least squares method.

[0041] Furthermore, the calculation unit 132 may identify the time when the vehicle 20 is stopped and immediately after it starts moving, based on the speed of the vehicle 20, and calculate the heat generation coefficient based on the input data excluding the identified time. In this case, the calculation unit 132 can generate time-series data of the heat generation coefficient while excluding the effects of road surface temperature (heat transfer from the road surface) and weather (for example, temperature rise due to direct sunlight). Then, using such time-series data of the heat generation coefficient, the determination unit 133 can accurately determine the remaining tread depth of the tire 30 by the process described below.

[0042] The determination unit 133 determines the condition of the tire 30, including the remaining tread, based on time-series data of the heat generation coefficient. Here, the heat generation coefficient is a coefficient that includes both the heat generation due to the load of the vehicle 20 (load-derived) and the heat generation due to the remaining tread of the tire 30 (tread-derived). Heat generation due to the load corresponds to the increase in the internal pressure of the tire 30 as the vehicle 20 loads a load, causing the internal temperature of the tire to rise according to Boyle's Law and Charles's Law. Heat generation due to the remaining tread corresponds to the phenomenon where the heat generation of the tread of the tire 30 decreases as the remaining tread of the tire 30 decreases. Here, the change in the heat generation coefficient due to the load occurs in accordance with the loading and unloading of a load onto the vehicle 20, and for the rear wheels, it may show a change of 2 to 3 times in a few hours. On the other hand, the change in the heat generation coefficient due to the remaining tread shows a change of 1.2 to 1.4 times per year from a new state until the tire 30 is worn, and decreases monotonically unless the tire 30 is replaced. The determination unit 133 can determine the condition of the remaining tread of the tire 30 by utilizing the differences in these changes in the heat generation coefficient and extracting only the changes originating from the remaining tread from the time-series data of the heat generation coefficient.

[0043] Figure 4 shows an example of time-series data of the heat generation coefficient, indicated by each dot. The determination unit 133 extracts a first component, represented by a high-frequency curve originating from the load of the vehicle 20, and a second component, represented by an envelope, originating from the wear of the tire 30, from the time-series data of the heat generation coefficient calculated by the calculation unit 132. The determination unit 133 can determine the condition of the remaining tread based on the second component, which decreases monotonically unless the tire 30 is replaced. In this way, the tire condition management device 10 can manage the condition of the tire 30, including the remaining tread, based on the internal temperature of the tire by introducing the heat generation coefficient.

[0044] The tread depth status determined by the determination unit 133 may include at least one of the following: a first state in which the tire 30 does not need to be replaced; a third state in which the tire 30 needs to be replaced; and a second state which is intermediate between the first and third states and indicates that the tire is approaching the third state. For example, if any of the first, second, or third states is displayed on the terminal device 50, it becomes easier for the vehicle manager or others to determine when it is time to replace the tire 30. Here, the tread depth status determined by the determination unit 133 is not limited to these three states. It is preferable that at least the third state is determined, and all of the first to third states (all states) may be determined, but for example, only the third state may be determined and displayed on the terminal device 50 along with a warning. As another example, the second state may be determined and displayed on the terminal device 50 along with a message indicating that it is time to replace the tire. As another example, if only the first state is determined and displayed on the terminal device 50, the vehicle manager may determine that the time for tire replacement is approaching when the determination of the first state is no longer displayed on the terminal device 50 (the determination display disappears).

[0045] Here, the determination unit 133 may set a reference value in advance based on the maximum value in the time-series data of the heat generation coefficient since the tire 30 was replaced, and determine that the third state is present if the calculated heat generation coefficient falls below the reference value. Since the amount of wear on the tire 30 is affected by the nature of driving, determining the change in state after a certain period of time (for example, 2 years from the time of replacement) may be inaccurate. By utilizing the property that the second component of the heat generation coefficient decreases monotonically as long as the tire 30 is not replaced, and by setting the above reference value, the remaining tread depth of the tire 30 can be accurately determined while excluding the influence of the nature of driving. The reference value may be set to, for example, 80% of the maximum value.

[0046] Furthermore, the determination unit 133 can determine whether or not the vehicle 20 is loaded based on the first component. Therefore, the tire condition management device 10 can also manage the condition of the vehicle 20 based on the internal tire temperature. As described above, the first component of the heat generation coefficient for the rear wheels shows a change of 2 to 3 times, so by setting an appropriate threshold in the middle of the range of change, it is possible to determine whether or not the vehicle 20 is loaded.

[0047] Here, the determination unit 133 may determine whether or not the vehicle 20 is loaded using the ratio of the first component of the front wheels to the first component of the rear wheels. For example, weather conditions can act as noise, causing the heat generation coefficient to change. Specifically, in the case of heavy rain, the amount of heat generated may decrease in all tires 30 mounted on the vehicle 20. The determination unit 133 may, for example, calculate the ratio of the first component of the heat generation coefficient of the rear tires divided by the first component of the heat generation coefficient of the front tires, and then determine whether or not the vehicle 20 is loaded by setting an appropriate threshold in the middle of the range of change for the calculated ratio. In other words, if the value of the ratio is greater than or equal to the threshold, it can be determined that there is a load, and if the value of the ratio is less than the threshold, it can be determined that there is no load (empty). By using the ratio of the first component of the front wheels to the first component of the rear wheels, the influence of noise can be reduced, and the presence or absence of a load in the vehicle 20 can be accurately determined.

[0048] Furthermore, the determination unit 133 can determine whether the tire 30 is a front wheel or a rear wheel using the heat generation coefficient. For example, the front wheel tire and the rear wheel tire can be distinguished based on the attribute data regarding the tire 30. However, information such as the classification of the front or rear wheel of the tire 30 is often manually registered by the operator when the tire 30 is replaced, and may be incorrectly registered. Here, when the tire 30 is mounted as a front wheel, the load on the tire 30 is greater than when it is mounted as a rear wheel. This is because the front wheel tire continues to have a high load regardless of whether the vehicle 20, which is a truck, is unloaded or loaded with cargo. For the rear wheel tire, the load varies greatly depending on whether the vehicle 20 is unloaded or loaded with cargo, so the change in the heat generation coefficient becomes large. Utilizing such a difference in the change of the heat generation coefficient, the determination unit 133 can determine whether the tire 30 is a front wheel or a rear wheel.

[0049] FIG. 6 is a diagram for explaining the determination of the front and rear wheels based on the heat generation coefficient. The determination unit 133 may extract data for a specific period (for example, the most recent one month) from the time series data of the heat generation coefficient, and generate a histogram of the number of running times according to the value of the heat generation coefficient for each of the tires 30 mounted on the vehicle 20. In the example of FIG. 6, the heat generation coefficient is divided into several data intervals from V0 to V1 (V0 < V1). The determination unit 133 extracts the upper 20% value and the lower 20% value from each histogram of the tire 30, and calculates the difference in the heat generation coefficient (interval of the data interval) between them. For the rear wheel, the interval of the data interval becomes larger than that of the front wheel. Therefore, the determination unit 133 can accurately determine the front and rear wheels based on the heat generation coefficient. Here, the reason for extracting the upper and lower 20% values is to exclude the influence of the values (erroneous data) belonging to the upper or lower positions due to the influence of noise. Therefore, if the influence of noise can be excluded, the extracted values are not limited to the upper and lower 20% values.

[0050] Furthermore, for a vehicle 20 with double rear tires (two wheels), the determination unit 133 can determine whether a tire 30 is an inner rear tire or an outer rear tire by utilizing the difference in the change in the heat coefficient, similar to how it distinguishes between front and rear wheels. Here, an outer rear tire is a rear wheel that is closer to the outside in the left-right direction of the vehicle 20. An inner rear tire is a rear wheel that is closer to the inside (center of the vehicle 20) in the left-right direction of the vehicle 20. The load on an outer rear tire 30 is smaller than that on an inner rear tire 30. In other words, an inner rear tire is subjected to a higher load than an outer rear tire, and the difference in load becomes particularly large when a load is loaded. Therefore, in the method for distinguishing between front and rear wheels described above, by replacing the front wheel with an inner rear tire and the rear wheel with an outer rear tire, it is possible to accurately determine whether a tire is an inner or outer rear tire based on the heat coefficient. As described above, the determination unit 133 generates a histogram for a specific period from the time-series data of the heat generation coefficient, and can determine whether the tire 30 is a front wheel or a rear wheel based on the difference between the highest and lowest values ​​extracted from the histogram. Furthermore, the determination unit 133 generates a histogram for a specific period from the time-series data of the heat generation coefficient, and can determine whether the tire 30 is an inner rear wheel or an outer rear wheel based on the difference between the highest and lowest values ​​extracted from the histogram.

[0051] The output unit 134 may output the determination result from the determination unit 133 (for example, whether the remaining tread of the tire 30 falls into one of the first to third states described above) to a terminal device 50 used by an administrator managing the vehicle 20. Furthermore, if the determination result is the third state, which requires replacement of the tire 30, the output unit 134 may output a warning message, etc., to the terminal device 50. The administrator may then plan or execute the replacement of the tire 30 based on the displayed determination result.

[0052] Figure 5 is an example flowchart showing the processing of the tire condition management method executed by the tire condition management device 10 according to this embodiment.

[0053] The acquisition unit 131 acquires input data including time-series data of the tire temperature and the vehicle speed detected by the detection device 70 mounted on the vehicle 20 (step S1). The input data may further include information on the ambient temperature.

[0054] The calculation unit 132 calculates the heat generation coefficient based on the input data, using a model in which the heating component of the rate of increase in tire temperature is calculated by multiplying the proportional component of the vehicle speed 20 by the heat generation coefficient (step S2).

[0055] The determination unit 133 extracts from the time-series data of the heat generation coefficient a first component represented by a high-frequency curve originating from the load of the vehicle 20 and a second component represented by an envelope originating from the wear of the tire 30 (step S3).

[0056] The determination unit 133 determines the condition of the remaining tread based on the second component (step S4). The condition of the remaining tread determined by the determination unit 133 may include a first state in which the tire 30 does not need to be replaced, a third state in which the tire 30 needs to be replaced, and a second state which is intermediate between the first and third states and indicates that the tire is approaching the third state.

[0057] The output unit 134 outputs the determination result from the determination unit 133 (for example, whether the remaining tread of the tire 30 is in one of the first to third states described above) to a terminal device 50 used by the administrator who manages the vehicle 20 (step S5).

[0058] As described above, the tire condition management device 10, program, and tire condition management method according to this embodiment can manage the condition of the tire 30, including the remaining tread depth, based on the internal tire temperature measured in a typical vehicle 20. The method of this disclosure does not require expensive devices and can easily predict the condition of the remaining tread depth of the tire 30.

[0059] While embodiments of this disclosure have been described based on the drawings and examples, it should be noted that those skilled in the art will find it easy to make various modifications or alterations based on this disclosure. Therefore, it should be noted that these modifications or alterations are included within the scope of this disclosure. For example, the functions included in each component or step can be rearranged in a logically consistent manner, and multiple components or steps can be combined into one or separated. Embodiments relating to this disclosure can also be realized as storage media recording programs executed by a processor in the device. These are also understood to be included within the scope of this disclosure. Contribution to the United Nations-led Sustainable Development Goals (SDGs)

[0060] The SDGs have been proposed to realize a sustainable society. One embodiment of this disclosure is considered to be a technology that can contribute to "No. 9 Industry, Innovation and Infrastructure" and other goals. [Explanation of Symbols]

[0061] 10. Tire condition management device 11 Communications Department 12 Storage section 13 Control Unit 20 vehicles 30 tires 40 Networks 50 Terminal devices 70 Detection device 80 In-vehicle communication device 90 Storage device 131 Acquisition Department 132 Arithmetic section 133 Judgment section 134 Output section

Claims

1. A tire condition management device that manages the condition of tires mounted on a vehicle, including at least the remaining tread depth, An acquisition unit that acquires input data including time-series data of the tire temperature and the vehicle speed, respectively, detected by a detection device mounted on the vehicle, A calculation unit that calculates the heat generation coefficient based on the input data, using a model in which the heating component of the rate of increase in the temperature inside the tire is calculated by multiplying the proportional component of the vehicle's speed by the heat generation coefficient, A tire condition management device comprising: a determination unit that extracts a first component represented by a high-frequency curve originating from the load of the vehicle and a second component represented by an envelope originating from the wear of the tire from the time-series data of the calculated heat generation coefficient, and determines the state of the remaining tread based on the second component.

2. The tire condition management device according to claim 1, wherein the condition of the remaining tread determined by the determination unit includes at least one of a first condition in which the tire does not need to be replaced, a third condition in which the tire needs to be replaced, and a second condition which is intermediate between the first condition and the third condition and indicates that the tire is approaching the third condition.

3. The tire condition management device according to claim 2, wherein the determination unit sets a reference value in advance based on the maximum value in the time-series data of the heat generation coefficient since the tire was replaced, and determines that the third state is occurring when the calculated heat generation coefficient falls below the reference value.

4. The tire condition management device according to any one of claims 1 to 3, wherein the calculation unit identifies the time when the vehicle is stopped and immediately after it starts moving based on the speed of the vehicle, and calculates the heat generation coefficient based on the input data excluding the identified time.

5. The tire condition management device according to any one of claims 1 to 3, wherein the determination unit determines whether or not the vehicle is loaded based on the first component.

6. The tire condition management device according to claim 5, wherein the determination unit determines whether or not the vehicle is loaded using the ratio of the first component of the front wheel and the first component of the rear wheel of the vehicle.

7. The tire condition management device according to any one of claims 1 to 3, wherein the determination unit generates a histogram for a specific period from the time-series data of the heat generation coefficient, and determines whether the tire is a front wheel or a rear wheel based on the difference between the upper and lower values ​​extracted from the histogram.

8. The tire condition management device according to any one of claims 1 to 3, wherein the determination unit generates a histogram for a specific period from the time-series data of the heat generation coefficient, and determines whether the tire is an inner rear wheel or an outer rear wheel based on the difference between the upper and lower values ​​extracted from the histogram.

9. A tire condition management device that manages the condition of tires mounted on a vehicle, including at least the remaining tread depth, The system acquires input data including time-series data of the tire temperature and the vehicle's speed, respectively, as detected by a detection device mounted on the vehicle. Using a model in which the heating component of the rate of increase in the temperature inside the tire is calculated by multiplying the proportional component of the vehicle's speed by the heat generation coefficient, the heat generation coefficient is calculated based on the input data, A program that extracts a first component, represented by a high-frequency curve originating from the vehicle load, and a second component, represented by an envelope, originating from tire wear, from the time-series data of the calculated heat generation coefficient, and determines the state of the remaining tread based on the second component.

10. A tire condition management method performed by a tire condition management device that manages the condition of tires mounted on a vehicle, including at least the remaining tread depth, The system acquires input data including time-series data of the tire temperature and the vehicle's speed, respectively, as detected by a detection device mounted on the vehicle. Using a model in which the heating component of the rate of increase in the temperature inside the tire is calculated by multiplying the proportional component of the vehicle's speed by the heat generation coefficient, the heat generation coefficient is calculated based on the input data, A tire condition management method comprising: extracting a first component represented by a high-frequency curve originating from the load of the vehicle and a second component represented by an envelope originating from the wear of the tire from the time-series data of the calculated heat generation coefficient; and determining the state of the remaining tread based on the second component.

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