JP2019070561A - Tire degradation diagnosis device and tire degradation diagnosis system - Google Patents

Abstract

A tire deterioration diagnosis apparatus capable of diagnosing a deterioration state of a tire regardless of a use state of the tire. SOLUTION: First acquisition means 11 for acquiring a deterioration index value representing the degree of deterioration of a tire 20 attached to a vehicle 100, and second acquisition means for acquiring a travel distance of the vehicle 100 from the start of use of the tire 20. 12, a storage unit 13 that stores correlation information indicating a relationship between the deterioration index value and the travel distance in advance, and a first correction correlation in which the correlation information is corrected using the deterioration index value and the travel distance acquired at the first time point. Correction means 14 for generating information and second corrected correlation information obtained by correcting the correlation information using the deterioration index value and travel distance acquired at a second time point after the first time point, and first corrected correlation information And determining means 15 for determining the deterioration pace of the tire 20 by comparing the second corrected correlation information. [Selection] Figure 1

Description

  The present invention relates to a tire deterioration diagnosis device that diagnoses the deterioration state of a tire, and a tire deterioration diagnosis system.

  In the pneumatic tire, in order to fully exhibit its function and performance, it is desirable to always know the deterioration state of the tire. For example, in a tire mounted on a vehicle (car, truck, bus, two-wheeled vehicle, forklift, etc.), deterioration and wear of rubber constituting the tread proceed due to use of a long distance. Moreover, degradation progresses gradually also about rubber | gum other than a tread, and fiber, resin, and a metallic member which are not exposed to the surface of a tire. Such deterioration of the tire component affects the traveling performance, safety, fuel consumption and the like of the vehicle. In addition, when the tire constituent member is deteriorated, the noise, vibration and harshness (NVH) from the tire are deteriorated, so that the comfort when traveling the vehicle is also deteriorated. Therefore, an attempt has been made to diagnose the deterioration state of a tire mounted on a vehicle.

  For example, in the retread tire, the current physical property value of the case component is estimated, and the distance that can be traveled until the current physical property value reaches the limit physical property value is referred to the correlation information indicating the relationship between the physical property value and the traveling distance. An apparatus for prediction is developed (see, for example, Patent Document 1).

  Also, with reference to correlation information indicating the relationship between the radial acceleration and the degree of wear of the tire tread, a device has been developed to estimate the degree of wear of the tire tread from the radial acceleration detected by the acceleration sensor provided on the tire. (See, for example, Patent Document 2).

Patent No. 5347054 JP, 2016-190615, A

  However, the state of tire deterioration is greatly affected not only by the aged deterioration of the tire itself, but also by the use of the tire as well as the driving technology such as steering wheel operation and brake operation, and vehicle settings such as wheel alignment. . Therefore, in the device of Patent Document 1 using correlation information created in advance and the device of Patent Document 2, highly reliable prediction can be made in the use situation out of the use situation of the tire assumed at the time of creation of the correlation information. The result can not be obtained, and the predicted result and the actual result may be largely different. As described above, in the conventional device, there is a problem that it is difficult to accurately diagnose the deterioration state of the tire depending on the use condition of the tire.

  The present invention has been made in view of the above problems, and it is an object of the present invention to provide a tire deterioration diagnosis apparatus and tire deterioration diagnosis system capable of diagnosing the deterioration state of a tire regardless of the use condition of the tire. Do.

The characteristic configuration of the tire deterioration diagnosis device according to the present invention for solving the above-mentioned problems is:
First acquisition means for acquiring a deterioration index value representing a degree of deterioration of a tire attached to a vehicle;
A second acquisition unit for acquiring a travel distance of the vehicle from the start of use of the tire;
Storage means for storing in advance correlation information indicating a relationship between the deterioration index value and the traveling distance;
First corrected correlation information in which the correlation information is corrected using the deterioration index value and the traveling distance acquired at the first time point, and the deterioration index value and traveling distance acquired at the second time point after the first time point Correction means for generating second correction correlation information obtained by correcting the correlation information using
Determining means for determining a deterioration pace of the tire by comparing the first corrected correlation information with the second corrected correlation information;
To be equipped.

  According to the tire deterioration diagnosis device of the present configuration, the first corrected correlation information in which the correlation information is corrected using the deterioration index value and the travel distance acquired at the first time, the deterioration index value acquired at the second time, The deterioration pace of the tire from the first time point to the second time point can be recognized by comparing the second corrected correlation information in which the correlation information is corrected using the travel distance. Therefore, even when there is a change in the use condition of the tire between the first time point and the second time point, the correlation information is corrected using the deterioration index value acquired during the use period of the tire, and the tire deterioration is caused. It is possible to reflect the pace of deterioration in diagnosis. Therefore, it is possible to appropriately diagnose the deterioration state of the tire even in the use state deviated from the use state of the tire assumed at the time of creation of the correlation information.

In the tire degradation diagnostic device according to the present invention,
The correlation information indicates a master curve that continuously decreases or increases when graphed in a coordinate system in which the first axis is a travel distance and the second axis is a deterioration index value,
The correction means converts the master curve in the coordinate system to generate a first correction curve passing through coordinates corresponding to the deterioration index value and the travel distance acquired at the first time point. Preferably, the second correction correlation information is generated by generating correction correlation information and generating a second correction curve passing through the deterioration index value acquired at the second time and coordinates corresponding to the travel distance.

  According to the tire deterioration diagnosis device of this configuration, the comparison of the first correction correlation information and the second correction correlation information becomes easy by generating the first correction curve and the second correction curve. It is possible to accurately and easily recognize the degradation rate of the tire up to the point in time.

  In the tire deterioration diagnosis device according to the present invention, the conversion may be a conversion in which the master curve is moved in parallel along the first axis, a conversion in which the master curve is moved in parallel along the second axis, and It is preferable that it is at least one selected from the group consisting of similarity transformations that enlarge or reduce the master curve.

  According to the tire deterioration diagnosis device of this configuration, the first correction curve and the second correction curve suitable for the determination of the deterioration pace can be easily generated by using the above-mentioned appropriate conversion.

In the tire degradation diagnostic device according to the present invention,
The storage means further stores a predetermined limit deterioration index value.
The determination means compares a first limit travel distance corresponding to the limit deterioration index value on the first correction curve with a second limit travel distance corresponding to the limit deterioration index value on the second correction curve. It is determined that the deterioration pace is suppressed when the second limit travel distance is larger than the first limit travel distance, and the deterioration pace is determined when the second limit travel distance is smaller than the first limit travel distance. It is preferable to determine that it has been promoted.

  According to the tire deterioration diagnosis device of the present configuration, the first correction curve and the second correction curve can be accurately and easily compared by using the predetermined limit deterioration index value.

  In the tire deterioration diagnosis device according to the present invention, the deterioration index value may be an integrated value of internal pressure of the tire, an integrated value of internal temperature of the tire, a modulus of tread rubber of the tire, a hardness of the tread rubber, the tread rubber The tire is preferably at least one selected from the group consisting of: wear amount of the tire, depth of grooves formed in the tread of the tire, and uniformity of the tire.

  According to the tire deterioration diagnosis device of the present configuration, the deterioration pace of the tire can be appropriately recognized by using the above-mentioned appropriate deterioration index value.

  Preferably, the tire deterioration diagnosis device according to the present invention further comprises notification means for notifying the determination result by the determination means.

  According to the tire deterioration diagnosis device of the present configuration, it is possible to cause the driver, the vehicle manager, and the like to quickly and easily recognize the deterioration pace of the tire by notifying the determination result by the determination means.

The characteristic configuration of the tire deterioration diagnosis system according to the present invention for solving the above-mentioned problems is:
A tire having a sensor that senses the state of a tire component;
The tire deterioration diagnosis device according to any one of the above,
A tire degradation diagnostic system comprising
The first acquisition means in the tire deterioration diagnosis device is to acquire the deterioration index value based on sensing information transmitted from the tire.

  According to the tire deterioration diagnosis system of the present configuration, since the deterioration index value is acquired based on the sensing information transmitted from the tire, the deterioration pace of the running tire can be determined while running, and the determination The results can be presented to the driver in real time.

FIG. 1 is a block diagram of a tire deterioration diagnosis system according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of a table for recording the deterioration index value, the tire travel distance, and the correction correlation information. FIG. 3 is an explanatory view of correlation information showing the relationship between the tire travel distance and the deterioration index value. FIG. 4 is an explanatory diagram of the corrected correlation information generated by the correction means. FIG. 5 is an explanatory view of tire deterioration pace determination in the determination means. FIG. 6 is an explanatory view of the additional deterioration determination in the determination means. FIG. 7 is a flowchart showing the processing procedure of the tire deterioration diagnosis program.

  Hereinafter, the present invention will be described with reference to FIGS. 1 to 7. However, the present invention is not intended to be limited to the configurations described in the embodiments and drawings described below.

<Tire deterioration diagnosis system>
FIG. 1 is a block diagram of a tire deterioration diagnosis system 1 according to an embodiment of the present invention. The tire deterioration diagnosis system 1 includes a tire deterioration diagnosis device 10 mounted on a vehicle 100 and a tire 20 attached to the vehicle 100, and diagnoses the deterioration pace of the tire 20.

  The tire 20 is a pneumatic tire with a sensing function having a sensing unit 21. The sensing unit 21 includes a sensor unit 22 installed in a tread, a sidewall, a bead unit, and the like of the tire 20, and a transmission unit 23 that transmits sensing information from the sensor unit 22 to the vehicle 100 side. The sensor unit 22 is, for example, various sensors such as a temperature sensor, a strain sensor, an air pressure sensor, and an acceleration sensor, and states (temperature, strain, etc.) of components of the tire 20 such as inner liners, plies, belts, and rubber. To

<Tire deterioration diagnosis device>
The tire deterioration diagnosis device 10 includes a first acquisition unit 11, a second acquisition unit 12, a storage unit 13, a correction unit 14, and a determination unit 15, and includes an notification unit 16 as an optional configuration. The tire deterioration diagnosis device 10 further includes a first communication unit 17 that receives sensing information from the transmission unit 23 by non-contact communication such as short distance wireless communication (RFID) and an arbitrary place of the vehicle 100 by CAN (Controller Area Network). And a second communication unit 18 in communication with the electronic control unit 30 provided in the The first acquisition unit 11, the second acquisition unit 12, the correction unit 14, the determination unit 15, and the notification unit 16 are a computer having a CPU, a memory, a storage, and the like. Each function is realized by reading out and executing.

  The first acquisition means 11 periodically (eg, once a week) acquires a deterioration index value representing the degree of deterioration of the tire 20. The deterioration index value acquired by the first acquisition unit 11 is accumulated, for example, in a storage (not shown). The deterioration index value includes the tire 20 among sensing information in the sensor unit 22, physical property values of constituent members of the tire 20 (hereinafter simply referred to as "physical property values"), and index values indicating the shape of the tire 20. The one having a continuous increasing or decreasing property with respect to the traveling distance of the vehicle 100 in a state of being attached can be used. Here, the deterioration index value "having a continuously increasing or decreasing property" includes a monotonous increase or a monotonous decrease, but in the case where it constantly increases or decreases throughout the entire period from the start of use of the tire 20 to the end. Not only if, for example, only when the beginning of use increases and then decreases, but the remaining period monotonically increases or decreases except for some periods where the proportion of the total period of use is sufficiently small. Also includes In addition, it is not necessary to be a strictly monotonous increase or monotonous decrease in the mathematical sense, and there is a minute increase or decrease with a sufficiently small fluctuation amount as compared to the increase or decrease amount in the entire service period of the tire 20 It is also good. For example, in the sensing information in the sensor unit 22, the physical value such as the integrated value of the internal pressure of the tire 20 and the integrated value of the internal temperature of the tire 20, an index indicating the shape of the tire 20, such as the modulus and hardness of the tread rubber In terms of values, the amount of wear of tread rubber, the depth of grooves formed in the tread, and uniformity etc. monotonically increase or decrease with the distance traveled by the vehicle 100 with the tire 20 attached. It has a property and can be suitably used as a deterioration index value. These deterioration index values can be obtained by acquiring sensing information in the tire 20 via the first communication means 17 and calculating or estimating based on the sensing information. For example, the integrated value of the internal pressure of the tire 20 can be calculated as an accumulated value of sensing information of the air pressure sensor, and the integrated value of the internal temperature of the tire 20 can be calculated as an accumulated value of sensing information of the temperature sensor . The integrated value of the internal pressure of the tire 20 is the total amount of stress that the tire 20 receives, and the integrated value of the internal temperature of the tire 20 is the total amount of heat that the tire 20 receives. The hardness of the tread rubber can be calculated using sensing information of a strain sensor or the like disposed in the tread. The uniformity can be calculated from the change in acceleration in the tire radial direction during constant speed traveling by installing an acceleration sensor in the bead portion. As another example, a database indicating the correspondence between sensing information and an arbitrary degradation index value is prepared in advance, and the degradation index value can be estimated from the sensing information by using this database.

  The second acquisition unit 12 synchronizes the travel distance of the vehicle 100 from the start of use of the tire 20 (hereinafter referred to as “tire travel distance”) with the acquisition of the deterioration index value by the first acquisition unit 11 and has a cycle (Eg, once a week) For example, the second acquisition unit 12 acquires the vehicle speed signal output from the transmission of the vehicle 100 from the electronic control unit 30 via the second communication unit 18, and calculates the tire travel distance from the time when the use of the tire 20 is started. It can be calculated. The tire travel distance acquired by the second acquisition unit 12 is stored in a storage (not shown) in association with the deterioration index value acquired at the same time by the first acquisition unit 11. Here, “acquired at the same time” is not limited to the case where the respective acquisition timings completely coincide, and the deterioration index value acquired by the first acquisition unit 11 and the tire acquired by the second acquisition unit 12 If it is possible to associate travel distances with each other, it also includes the case where there is a deviation in each acquisition timing. For example, when the acquisition of the deterioration index value by the first acquisition unit 11 and the acquisition of the tire travel distance by the second acquisition unit 12 are performed with a sufficiently short time lag as compared with the respective acquisition cycles, deterioration is It is possible to associate the index value with the tire travel distance.

  The storage unit 13 is, for example, a non-volatile semiconductor memory or the like, and correlation information indicating the relationship between the tire travel distance and the deterioration index value is recorded in advance in the recording area. The correlation information is prepared in advance by performing test travel on a drum, a test course, or the like using the same type of tire as the tire 20 and associating the measured tire travel distance with the deterioration index value. It is preferable that a predetermined deterioration index value (hereinafter, referred to as “limit deterioration index value”) be further recorded in the recording area of the storage unit 13. The limit deterioration index value is preferably, for example, a deterioration index value in a deterioration state where replacement of a tire is recommended.

  The correction unit 14 generates the corrected correlation information by correcting the correlation information using the deterioration index value and the tire travel distance acquired at the same time. The generation of the correction correlation information by the correction unit 14 is periodically performed, for example, each time the first acquisition unit 11 and the second acquisition unit 12 synchronously acquire the deterioration index value and the tire travel distance. It is preferable that the correction correlation information generated in the correction means 14 be stored in, for example, a storage (not shown) and managed in association with the deterioration index value and the tire travel distance used for the generation. FIG. 2 is a diagram showing an example of a table for recording the deterioration index value, the tire travel distance, and the correction correlation information. In the example of FIG. 2, by recording the correction correlation information as a function fc (Dm), the deterioration index value and the tire are obtained at each acquisition time of the deterioration index value and the tire travel distance (hereinafter simply referred to as “time”). It manages travel distance and correction correlation information.

  The determination means 15 determines the deterioration pace of the tire 20 by comparing the correction correlation information regarding two different time points generated by the correction means 14. In addition to the tire degradation pace determination, the determination means 15 is configured to execute another determination (hereinafter referred to as “additional degradation determination”) of diagnosing the degradation state of the tire 20 using correlation information. It is also good.

  The informing means 16 generates informing information for informing the driver, the vehicle manager or the like of the result of the tire deterioration pace determination in the determination means 15. The notification information is displayed, for example, on a display 40 provided on an instrument panel, a console or the like. The notification means 16 is further configured to generate additional notification information for notifying the determination result when the additional deterioration determination is performed in addition to the tire deterioration pace determination in the determination means 15, and to cause the display 40 or the like to display the additional notification information. May be

<Correlation information>
FIG. 3 is an explanatory view of correlation information showing the relationship between the tire travel distance and the deterioration index value. The correlation information may take various data formats such as a table, a function, etc. In FIG. 3, orthogonal coordinates with the first axis (horizontal axis) as the tire travel distance and the second axis (vertical axis) as the deterioration index value It shows the correlation information in graph form in the system. The correlation information graphed in this orthogonal coordinate system is hereinafter referred to as a master curve. FIG. 3A shows an example of a master curve obtained when the deterioration index value having monotonically decreasing property with respect to the tire travel distance is continuously plotted. FIG. 3 (b) shows a master curve obtained when the deterioration index value having monotonically increasing property with respect to the tire travel distance is continuously plotted.

  As the measurement results of the test run performed to create the correlation information show in FIG. 3 (a) and FIG. 3 (b) by the broken line section, the tendency of increase and decrease of the initial use start of the tire is the use period of the tire If it differs from the overall trend, the measurement result in the section where the deterioration index value monotonously increases or monotonically decreases as the tire travel distance increases as the section indicated by the solid line in FIG. 3 is used as a master curve . The master curve shown in FIG. 3 (a) decreases continuously, and the master curve shown in FIG. 3 (b) continuously increases. By collating the relationship between the deterioration index value and the tire travel distance on such a master curve, from the deterioration index value (hereinafter, referred to as “measurement deterioration index value”) Im acquired by the first acquisition means 11, The estimated value of the tire travel distance (hereinafter, referred to as "estimated travel distance") De can be uniquely estimated. Similarly, from the tire travel distance (hereinafter referred to as "measured travel distance") Dm acquired by the second acquisition means 12, an estimated value of the degradation index value (hereinafter referred to as "predicted degradation index value") Ie. It can be estimated.

<Correction correlation information>
FIG. 4 is an explanatory view of the correction correlation information generated by the correction means 14. The corrected correlation information can take the same data format as the correlation information. Here, as with the master curve shown in FIG. 3, the correction correlation information is graphed in the orthogonal coordinate system, and the correction curve is described.

  If the deterioration pace of the tire 20 in the traveling of the vehicle 100 is the same as the deterioration pace in the test travel in which the master curve is created, the coordinates corresponding to the measurement deterioration index value Im and the measurement travel distance Dm are plotted on the master curve Be done. However, in actual driving, when the conditions are different from the test driving, a deviation occurs between the coordinates corresponding to the measured deterioration index value Im and the measured travel distance Dm and the master curve. The correction means 14 generates a correction curve in which this deviation is eliminated.

  Specifically, the correction unit 14 refers to the table shown in FIG. 2 to obtain the measured deterioration index value Im1 acquired at time T1 and the coordinate a (Dm1, Im1) corresponding to the measured travel distance Dm1, As shown in FIG. 4A, a correction curve C1 passing through the coordinates a (Dm1, Im1) is generated by translating the master curve M along the horizontal axis. Similarly, referring to the table shown in FIG. 2, coordinates b (Dm2, Im2) corresponding to the measured deterioration index value Im2 acquired at time T2 and the measured travel distance Dm2 are acquired, and the master curve M is taken along the horizontal axis. By parallel translation, a correction curve C2 passing through the coordinate b (Dm2, Im2) is generated. The translational transformation of the master curve M along the horizontal axis can be implemented, for example, as a matrix operation on the master curve function f (Dm).

  The generation of the correction curve by the correction means 14 is not limited to the conversion in which the master curve M shown in FIG. 4A is moved in parallel along the horizontal axis, but can be implemented by performing another conversion on the master curve M. For example, as shown in FIG. 4B, the correction curve C1 passing through the coordinates a (Dm1, Im1) with respect to time T1 is also generated by the parallel movement of the master curve M along the vertical axis. It is also possible to generate a correction curve C2 passing through the coordinates b (Dm2, Im2). Further, the parallel movement of the master curve M is not limited to that along the horizontal axis or the vertical axis, but it is also possible to generate the correction curves C1 and C2 by parallel moving the master curve M in the oblique direction. Furthermore, as shown in FIG. 4C, the correction curve C1 passing through the coordinates a (Dm1, Im1) with respect to the time T1 is also generated by the similarity transformation that enlarges or reduces the master curve M centering on the origin of the orthogonal coordinate system. It is also possible to generate a correction curve C2 passing through coordinates b (Dm2, Im2) with respect to time T2.

  The transformation to be applied to the master curve to generate the correction curve, if it does not impair the continuous decreasing or increasing properties of the master curve, besides the translational transformation and similarity transformation, the expansion in the horizontal axis direction Other transforms, such as transforms, vertical transforms, etc. may also be used. Each of the transformations applied to the above-described master curve M can be implemented as a matrix operation on the master curve function f (Dm).

<Tire deterioration pace judgment>
FIG. 5 is an explanatory view of the tire deterioration pace determination in the determination means 15. The determination unit 15 uses the limit deterioration index value Ir recorded in the storage unit 13 to calculate the tire travel distance corresponding to the limit deterioration index value Ir from correction curves at two different points in time (hereinafter referred to as “limit travel distance Dr” By determining the deterioration pace of the tire 20 between the two points in time. The calculation of the limit travel distance Dr can be implemented as the calculation of the inverse function gc (Im) of the correction curve function fc (Dm).

  In FIG. 5A, the correction curve C1 is generated by translating the master curve along the horizontal axis so as to pass through the deterioration index value obtained at time T1 and the coordinate a corresponding to the tire travel distance. It is. Similarly, the correction curve C2 is generated so as to pass the coordinate b for the time T2 after the time T1, and the correction curve C3 passes the coordinate c for the time T3 after the time T2. It is generated.

  For example, when determining the deterioration pace between time T1 and T2 with the time T1 as the first time point and the time T2 as the second time point, for example, the limit travel corresponding to the limit deterioration index value Ir in the correction curve C1 The distance Dr1 is calculated, the limit travel distance Dr2 corresponding to the limit deterioration index value Ir in the correction curve C2 is calculated, and these are compared. If the limit travel distance Dr1 and the limit travel distance Dr2 are the same, that is, if the correction curve C1 and the correction curve C2 coincide with each other, the deterioration pace of the tire 20 between time T1 and T2 is the test travel in which the master curve was created. It is the same as the deterioration pace in However, as shown in FIG. 5A, when the limit travel distance Dr2 is larger than the limit travel distance Dr1, the deterioration pace of the tire 20 between times T1 and T2 is the deterioration in the test run in which the master curve was created. The determination means 15 determines that the deterioration pace of the tire 20 has been suppressed since it is slower than the pace. On the other hand, when the deterioration pace between time T2 and T3 is determined with time T2 as the first time and time T3 as the second time, the determination means 15 performs limit travel corresponding to the limit deterioration index value Ir in the correction curve C2. The distance Dr2 is calculated, the limit travel distance Dr3 corresponding to the limit deterioration index value Ir is calculated in the correction curve C3, and these are compared. In the example shown in FIG. 5A, since the limit travel distance Dr3 is smaller than the limit travel distance Dr2, the deterioration pace of the tire 20 between time T2 and T3 is lower than the deterioration pace in the test run in which the master curve was created. The determination means 15 determines that the deterioration pace of the tire 20 has been promoted. In the example shown in FIG. 5 (a), the correction curve decreases continuously, but as shown in FIG. 5 (b), even if the correction curve increases continuously, Similar determinations can be made. Specifically, in the example shown in FIG. 5B, since the limit travel distance Dr2 is larger than the limit travel distance Dr1, the determination means 15 determines that the deterioration pace of the tire 20 is suppressed between time T1 and T2. Do. Further, in the example shown in FIG. 5B, since the limit travel distance Dr3 is smaller than the limit travel distance Dr2, the determination means 15 determines that the deterioration pace of the tire 20 is promoted between time T2 and T3.

  The tire deterioration pace determination by the determination means 15 is not limited to determination based on the magnitude relationship of the limit travel distance Dr, as long as it compares correction curves at two different points in time, and may be by another method. It is also good. For example, using predetermined tire travel distances, deterioration index values corresponding to the tire travel distances are respectively calculated in correction curves at two different time points, and the deterioration pace is determined based on the magnitude relationship between these deterioration index values. It is also possible to configure.

  Further, the determination means 15 can be configured not only to simply determine whether the deterioration pace of the tire 20 is promoted or suppressed but also to evaluate the degree of promotion or suppression. For example, the determination unit 15 can evaluate how much the deterioration pace of the tire 20 is promoted or suppressed by calculating the “variation rate (%) of deterioration pace” as in the following formula.

    Rate of change of deterioration rate (%) = {(limit travel distance Dr2-limit travel distance Dr1) / limit travel distance Dr1} × 100

The judging means 15 evaluates that the deterioration pace of the tire 20 is suppressed as the fluctuation rate is larger when the fluctuation rate of the deterioration pace is a positive value, and the fluctuation rate of the deterioration pace is a negative value In addition, it is evaluated that the deterioration rate of the tire 20 is promoted as the fluctuation rate is smaller.
<Additional deterioration judgment>

  FIG. 6 is an explanatory view of the additional deterioration determination in the determination means 15. In the additional deterioration determination, the deterioration state of the tire 20 is diagnosed by calculating a distance (hereinafter, referred to as a "travelable distance") that can be traveled before the tire 20 is recommended to be replaced. is there. When the limit deterioration index value Ir recorded in advance in the storage unit 13 is a deterioration index value in a deterioration state where replacement of a tire is recommended, the travelable distance is a limit travel distance corresponding to the limit deterioration index value Ir. It is calculated as a difference ΔD between Dr and the measured travel distance Dm acquired by the first acquisition means 11. For example, as shown in FIG. 6A, the determination means 15 reads out the limit deterioration index value Ir from the storage means 13, calculates the limit travel distance Dr corresponding to the limit deterioration index value Ir in the correction curve C, and limits The travelable distance ΔD can be calculated from the difference between the travel distance Dr and the measured travel distance Dm.

  Further, as shown in FIG. 6B, it is also possible to calculate the travelable distance using a master curve. Specifically, determination means 15 calculates limit travel distance Drm corresponding to limit deterioration index value Ir in master curve M, and calculates travelable distance ΔD from the difference between limit travel distance Drm and measured travel distance Dm. be able to. However, in the example illustrated in FIG. 6B, the deterioration pace of the tire 20 is suppressed more than the deterioration pace in the test run in which the master curve is created, and the coordinates corresponding to the measurement deterioration index value Im and the measurement travel distance Dm. a is out of the master curve M. However, since the influence by the deterioration pace of the tire 20 is suppressed is not reflected in the travelable distance ΔD calculated using the master curve M shown in FIG. 6B, it is shown in FIG. It is smaller than the travelable distance calculated using the correction curve C. Therefore, the determination unit 15 calculates the “correction travelable distance ΔD ′” as in the following equation to reflect the influence of the deterioration pace of the tire 20 being suppressed or promoted, and the deterioration state of the tire 20. Can be diagnosed.

Corrected travelable distance ΔD '= travelable distance ΔD × (measured travel distance Dm / estimated travel distance De)
<Notification of judgment result>
The notification of the determination result can adopt various forms such as a form indicating whether the deterioration pace of the tire 20 is suppressed or promoted, a form indicating a degree of promotion or suppression, or the like. For example, when it is determined whether the deterioration pace of the tire 20 is simply suppressed or promoted in the determination means 15, the notification means 16 generates binary information indicating the determination result of "suppression" or "promotion". It is possible to constitute so that LED corresponding to each of "suppression" or "promotion" provided in an instrument panel, a console, etc. may be lighted based on binary information.

  In addition, when the change rate of the deterioration pace of the tire 20 is calculated in the determination means 15 and the degree of promotion or suppression is evaluated, the notification means 16 generates information indicating the change rate of the deterioration pace, The rate of change can be configured to be displayed on the display 40.

  The determination means 15 further displays the limit travel distance Dr on the display 40 by generating information notifying the limit travel distance Dr calculated using the latest measured deterioration index value Im and the correction curve corresponding to the measured travel distance Dm. It can be configured to be displayed. Since the limit travel distance Dr is a correction of the tire travel distance in which the tire 20 is in a recommended replacement state, reflecting the deterioration pace of the tire 20, the driver, the vehicle manager, etc. The deterioration state of the tire 20 can be accurately grasped by looking at the display of the travel distance Dr.

  In addition, as notification of the determination result of the additional deterioration determination, the notification means 16 generates information indicating the possible travel distance ΔD or the corrected possible travel distance ΔD ′ calculated by the determination means 15, and the possible travel distance ΔD or the corrected travel The possible distance ΔD ′ can be configured to be displayed on the display 40. The travelable distance ΔD and the correction travelable distance ΔD ′ are obtained by correcting the remaining distance that can be traveled before the tire 20 is in the recommended replacement state, reflecting the deterioration pace of the tire 20, The driver, the vehicle manager, and the like can accurately grasp the deterioration state of the tire 20 by viewing these displays on the display 40.

<Tire deterioration diagnosis program>
The tire deterioration diagnosis device 10 is a computer having a CPU, a memory, a storage, and the like, and the CPU reads out and executes a tire deterioration diagnosis program recorded in the memory to control its function. FIG. 7 is a flowchart showing the processing procedure of the tire deterioration diagnosis program. The detailed description of each step shown in the flowchart is omitted because it is redundant with the description of the tire deterioration diagnosis device 10 described above, and here, the procedure shown by the flowchart is mainly described.

  The computer that executes the tire deterioration diagnostic program repeatedly performs the processing of step 1 to step 11 to perform tire deterioration pace determination periodically (for example, once a week). First, by execution of step 1, the actual measurement deterioration index value Im is acquired based on the sensing information from the sensor unit 22. Thereby, the function of the first acquisition unit 11 is realized. Next, by executing step 2, the measured travel distance Dm is acquired from the electronic control unit 30. Thereby, the function of the second acquisition unit 12 is realized. The acquisition of the deterioration index value in step 1 and the acquisition of the tire travel distance in step 2 do not necessarily have to be performed in this order, and step 2 may be performed prior to step 1 or step 1 and step 1 2 may be executed in parallel.

  After completion of step 1 and step 2, step 3 is performed. In step 3, a correction curve is generated by translating the master curve in parallel so as to pass through the actual degradation index value Im obtained in step 1 and the coordinates corresponding to the actual travel distance Dm obtained in step 2. It is registered in the table shown in FIG. Thereby, the function of the correction means 14 is realized. After the completion of step 3, step 4 is executed to determine whether two or more correction curves are registered in the table shown in FIG. When two or more correction curves are not registered (step 4: No), the second correction curve is generated by repeating the process from step 1 after the standby process by execution of step 5, and the table is displayed in the table. be registered. The standby process of step 5 is to adjust the execution cycle (for example, once a week) of the tire deterioration pace determination using, for example, a timer function or the like.

  In the determination of step 4, when two or more correction curves are registered in the table (step 4: Yes), steps 6 to 9 are executed. In step 6, the limit deterioration index value Ir is read from the storage means 13, and among the correction curves registered in the table, the correction curve at the latest time (second time point) (for example, C2 of FIG. 5A) The limit travel distance Dr2 corresponding to the limit deterioration index value Ir is calculated using the correction curve of the second most recent time (first time point) among the correction curves registered in the table (for example, FIG. The limit travel distance Dr1 corresponding to the limit deterioration index value Ir is calculated using C1) of. In step 7, the limit travel distance Dr2 calculated in step 6 is compared with the limit travel distance Dr1. If the limit travel distance Dr2 is larger than the limit travel distance Dr1 (step 7: Yes), it is determined in step 8 that the deterioration pace of the tire 20 is suppressed. If the limit travel distance Dr2 is not larger than the limit travel distance Dr1 (step 7: No), it is determined in step 9 that the deterioration pace of the tire 20 is promoted. The functions of the determination unit 15 are realized by the execution of the steps 6 to 9.

  After completing steps 6 to 9, step 10 is performed. In step 10, notification information for notifying the driver, the vehicle manager or the like of the determination result in step 8 or the determination result in step 9 is generated and output to the display 40. Thereby, the function of the notification means 16 is realized.

  After the completion of step 10, step 11 is executed to determine whether to continue the processing of the tire deterioration diagnosis program. When continuing (Step 11: Yes), the process is repeated from Step 1 after the waiting process by execution of Step 5. When not continuing (Step 11: No), processing of a tire degradation diagnostic program is ended.

  As described above, the tire deterioration diagnosis system 1 and the tire deterioration diagnosis device 10 according to the embodiment of the present invention are the measurement deterioration index value Im1 and the measurement travel distance Dm1 acquired at time T1 (first time point). A correction curve C1 is generated by correcting the master curve M by using the correction curve C2 by correcting the master curve M by using the measurement deterioration index value Im2 acquired at time T2 (second time point) and the measurement travel distance Dm2. Do. Determining the deterioration pace of the tire 20 from the first time point to the second time point by comparing the correction curve C1 and the correction curve C2 with the limit travel distances Dr1 and Dr2 calculated from the respective correction curves Can. Therefore, even if there is a change in the use condition of the tire 20 between the first time point and the second time point, it is possible to reflect the deterioration pace in the deterioration diagnosis of the tire 20. Therefore, the deterioration state of the tire can be appropriately diagnosed regardless of the use condition of the tire 20.

[Another embodiment]
The tire deterioration diagnosis system and the tire deterioration diagnosis device of the present invention can also change the configuration described in the above embodiment as long as the effects of the present invention that the deterioration pace of the tire can be determined can be obtained. It is possible. Several such modifications are described as alternative embodiments.

Another Embodiment 1
In the tire deterioration diagnosis system 1 according to the above embodiment, the tire deterioration diagnosis device 10 can be provided outside the vehicle 100. For example, when the vehicle 100 is an electric vehicle (EV), the tire deterioration diagnosis device 10 may be provided in a power supply facility. In such a configuration, the tire deterioration diagnosis device 10 is stored when the sensing information acquired by the sensing unit 21 is stored in the storage provided in the vehicle 100 while traveling and connected to the power feeding facility to charge the vehicle 100. Can acquire tire travel distance and sensing information from the vehicle 100, and can determine the deterioration pace of the tire.

  As another example, the tire deterioration diagnosis device 10 is provided in a maintenance factory or the like, and when the vehicle 100 is maintained, the measurement deterioration index values Im and the measurement travel distance Dm at a plurality of time points are read from the table of FIG. It may be configured to determine the deterioration pace of

Another Embodiment 2
In the tire deterioration diagnosis system 1 according to the above-described embodiment, the tire deterioration diagnosis device 10 compares the corrected correlation information at two different points in time with the corrected correlation information (correction curve) at one point in time. You may comprise so that correlation information (master curve) may be compared. In such a configuration, it can be evaluated whether the deterioration pace from the start of use of the tire to the determination time point is suppressed or promoted more than the deterioration pace in the test run in which the master curve is created. Specifically, the limit travel distance Dr corresponding to the limit deterioration index value Ir is calculated using the correction curve, and the limit travel distance Drm corresponding to the limit deterioration index value Ir is calculated using the master curve, and the limit travel is The distance Dr is compared with the limit travel distance Drm. If the limit travel distance Dr in the correction curve is larger than the limit travel distance Drm in the master curve, it is determined that the deterioration pace from the start of use to the determination time is suppressed more than the deterioration pace in the test run. It is determined that the deterioration pace is promoted if the limit travel distance Dr of the second curve is smaller than the limit travel distance Drm at the master curve.

Another Embodiment 3
In the tire deterioration diagnosis system 1 according to the above embodiment, the tire deterioration diagnosis device 10 does not have the first communication means 17 as a component, and for example, the first communication means 17 can be separately provided in the vicinity of a tire house is there. With such a configuration, the arrangement of the tire deterioration diagnosis device 10 is not limited to the position where it can directly communicate with the sensing unit 21 provided in the tire 20, and therefore, vehicle design with a high degree of freedom is possible.

Another Embodiment 4
In the tire deterioration diagnosis system 1 according to the above-described embodiment, the tire deterioration diagnosis device 10 does not receive sensing information directly from the transmission unit 23, and periodically performs sensing information accumulated in a storage provided in the vehicle 100. It is also possible to configure to acquire from storage (for example, once a day).

Another Embodiment 5
In the tire deterioration diagnosis system 1 according to the above-described embodiment, the tire deterioration diagnosis device 10 does not necessarily have to calculate the deterioration index value and the tire travel distance in the first acquisition unit 11 and the second acquisition unit 12. For example, in the case where the deterioration index value or the tire travel distance is calculated in another electronic control unit mounted on the vehicle 100, the tire deterioration diagnosis device 10 receives the deterioration index value from the electronic control unit or the tire via CAN. The travel distance can be acquired by the first acquisition unit 11 and the second acquisition unit 12.

DESCRIPTION OF SYMBOLS 1 tire degradation diagnostic system 10 tire degradation diagnostic apparatus 11 1st acquisition means 12 2nd acquisition means 13 memory means 14 correction means 15 judgment means 16 alerting | reporting means 20 tire 22 sensor part (sensor)
100 vehicles

Claims (7)

First acquisition means for acquiring a deterioration index value representing a degree of deterioration of a tire attached to a vehicle;
A second acquisition unit for acquiring a travel distance of the vehicle from the start of use of the tire;
Storage means for storing in advance correlation information indicating a relationship between the deterioration index value and the traveling distance;
First corrected correlation information in which the correlation information is corrected using the deterioration index value and the traveling distance acquired at the first time point, and the deterioration index value and traveling distance acquired at the second time point after the first time point Correction means for generating second correction correlation information obtained by correcting the correlation information using
Determining means for determining a deterioration pace of the tire by comparing the first corrected correlation information with the second corrected correlation information;
Tire degradation diagnostic device equipped with. The correlation information indicates a master curve that continuously decreases or increases when graphed in a coordinate system in which the first axis is a travel distance and the second axis is a deterioration index value,
The correction means converts the master curve in the coordinate system to generate a first correction curve passing through coordinates corresponding to the deterioration index value and the travel distance acquired at the first time point. The second correction correlation information is generated by generating the correction correlation information, and generating a second correction curve passing through the coordinates corresponding to the deterioration index value and the travel distance acquired at the second time. The tire deterioration diagnostic device as described.   The transformation is from transformation for translating the master curve along a first axis, transformation for translating along a second axis, and similarity transformation for scaling the master curve about an origin of the coordinate system. The tire deterioration diagnosis device according to claim 2, which is at least one selected from the group consisting of The storage means further stores a predetermined limit deterioration index value.
The determination means compares a first limit travel distance corresponding to the limit deterioration index value on the first correction curve with a second limit travel distance corresponding to the limit deterioration index value on the second correction curve. It is determined that the deterioration pace is suppressed when the second limit travel distance is larger than the first limit travel distance, and the deterioration pace is determined when the second limit travel distance is smaller than the first limit travel distance. The tire degradation diagnostic device according to claim 2 or 3, wherein it is determined that acceleration has occurred.   The deterioration index value is an integrated value of the internal pressure of the tire, an integrated value of the internal temperature of the tire, a modulus of tread rubber of the tire, a hardness of the tread rubber, a wear amount of the tread rubber, and formed on the tread of the tire The tire degradation diagnostic device according to any one of claims 1 to 4, wherein the tire degradation diagnostic device is at least one selected from the group consisting of groove depths and tire uniformity.   The tire deterioration diagnosis device according to any one of claims 1 to 5, further comprising notification means for notifying a determination result by the determination means. A tire having a sensor that senses the state of a tire component;
The tire degradation diagnostic device according to any one of claims 1 to 6,
A tire degradation diagnostic system comprising
The tire deterioration diagnosis system according to claim 1, wherein the first acquisition unit in the tire deterioration diagnosis device acquires the deterioration index value based on sensing information transmitted from the tire.

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