JP6125156B2 - Tire judgment system and tire judgment method - Google Patents

Description

  The present invention relates to a tire determination system and a tire determination method.

  On roads that can travel at high speed, such as automobile-only roads, travel restrictions may be imposed depending on the weather conditions. There are various types of travel regulations, and one of them is a restriction that limits the types of tires that can be traveled. For example, in order to prevent slipping due to worsening weather or a decrease in temperature, restrictions may be imposed on running with winter tires.

  In addition, in order to predict the noise performance of a tire, a technique for simulating acoustic characteristics using a space formed between a tire model and a road surface as an acoustic tube model is known (for example, see Patent Document 1). Note that coasting noise (hereinafter referred to as traveling sound) generated from a traveling vehicle is roughly divided into tire road noise and vehicle noise as shown in FIG. 7, and tire road noise is 70% to 80% of the total noise. (Bridgestone Co., Ltd., “Basics and Practice of Automobile Tires”, first edition, Sankai-do Co., Ltd., January 2006, p. 190, etc.).

Japanese Patent Laid-Open No. 2007-237752

Conventionally, the type of tire attached to a vehicle traveling on a road has been visually confirmed, but there has been a problem that the visual confirmation is inaccurate. In addition, since visual confirmation takes time, it causes traffic congestion.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique capable of accurately determining the type of tire attached to a vehicle even while the vehicle is traveling.

  In order to achieve the above object, in the present invention, the type of tire mounted on the vehicle is determined based on the traveling sound of the vehicle traveling on the processed road surface that has been processed to flatten the road surface with respect to the road surface. To do. In other words, since the running sound includes sounds depending on the type of tire, the type of tire mounted on the vehicle can be determined by analyzing the running sound. In addition to the dependent components, various sound components are included.

  Among the components included in the running sound, a component that does not depend on the type of tire is noise that hinders the determination of the type of tire. The rougher the road surface, the larger the component of the noise. And the component of the traveling sound depending on the type of tire can be measured as the sound from the vehicle traveling on the flat road surface. Therefore, if the road surface is processed to flatten the road surface to obtain a processed road surface, and the running sound of the vehicle traveling on the processed road surface is acquired, the noise component is reduced compared to before the road surface is processed. The running sound of the state can be acquired. Therefore, by determining the tire type based on the traveling sound, it is possible to determine the tire type more accurately than when the traveling sound is acquired on the road surface before processing.

  Here, in the traveling sound acquisition means, it is only necessary to acquire a traveling sound including at least a noise generated from a tire among traveling sounds generated from a vehicle traveling on a processed road surface. What is necessary is just to acquire for every vehicle by the microphone etc. which were installed in the section within the predetermined distance from a toll booth. The processing of the road surface may be performed so that the processed road surface is flatter than the road surface before processing, and the upper surface of the paved road surface may be coated with a new road surface, or the paved road surface Part or all may be removed and re-paved, or the road surface may be polished, and various processing is possible.

  In addition, in order to process the road surface so that the processed road surface is flatter than the road surface before processing, the roughness of the road surface before and after processing may be measured and compared, or the type of road surface (paved For each type), specify the average road surface roughness in advance, and select the type of road surface after processing so that the processed road surface is flatter than the road surface roughness according to the type of road surface before processing. Various configurations may be employed.

  The tire determination means only needs to be able to determine the type of tire based on the running sound. When the component corresponding to the specific type of tire is included in the running sound, the specific type of tire is mounted on the vehicle. What is necessary is just to determine that it exists. The component corresponding to the specific type of tire may be specified by analyzing the running sound, for example, a configuration for determining the type of tire mounted on the vehicle based on the frequency characteristics of the running sound of the vehicle. It can be adopted.

  Various types of tires can be defined, and tires that can have different sounds during traveling due to different types may be defined as different types of tires. Examples of tire types that can be defined in this way include summer tires and winter tires. Therefore, for example, if the frequency characteristics of the traveling sound of a vehicle with summer tires and winter tires are defined in advance, the measured frequency characteristics of the traveling sound of the vehicle are compared with the predefined frequency characteristics of the traveling sound. By doing so, the type of tire can be determined. The frequency characteristic is a relationship between the physical property of the sound wave and the frequency, and may be a relationship in which the characteristics of the summer tire and the winter tire appear distinguishably. Therefore, the relationship between the intensity of sound waves (sound pressure), the tone of sound waves (waveform), etc. and the frequency is defined, and when the characteristics of summer tires and winter tires appear, these characteristics are used as the frequency characteristics of summer and winter tires. Define it.

  The frequency characteristics of the summer tire and the winter tire may be defined for both the summer tire and the winter tire, or may be defined for only one of them. If the former, it is determined whether or not the frequency characteristic of the running sound is the frequency characteristic of the vehicle with the summer tire mounted, and further whether or not it is the frequency characteristic of the running sound of the vehicle with the winter tire mounted. It becomes the structure which determines. If the latter, it is determined whether or not the frequency characteristic of the traveling sound is the frequency characteristic of the traveling sound of the vehicle equipped with the winter tire, and if it is not the frequency characteristic of the traveling sound of the vehicle equipped with the winter tire. Can adopt a configuration for determining that it is a frequency characteristic of a running sound of a vehicle equipped with summer tires. Of course, it is determined whether or not the frequency characteristic of the running sound of the vehicle with the summer tire is attached. If the frequency characteristic of the running sound of the vehicle with the summer tire is not found, the driving of the vehicle with the winter tire is run. You may employ | adopt the structure determined to be the frequency characteristic of a sound.

  Furthermore, it is good also as a structure which processes a road surface on specific conditions and acquires a running sound. That is, a configuration may be adopted in which traveling sound is acquired without processing the road surface when the specific condition is not satisfied, and traveling sound is acquired by processing the road surface when the specific condition is satisfied. The specific condition includes, for example, a state in which the type of tire mounted on the vehicle cannot be determined based on the running sound of the vehicle traveling on the road surface. That is, the road surface is processed when the road surface before processing is rough and the type of tire cannot be determined with high accuracy by the traveling sound of the vehicle traveling on the road surface. According to this configuration, even if the type of tire cannot be determined with high accuracy before processing, the type of tire can be determined with higher accuracy by processing.

  Note that the state in which the type of tire mounted on the vehicle cannot be determined based on the running sound of the vehicle traveling on the road surface is the actual tire type based on the traveling sound of the vehicle traveling on the road surface. When the determination is attempted, it may be preliminarily defined as a state where determination cannot be performed or a determination reliability is equal to or less than a predetermined reliability. For example, it is possible to adopt a configuration in which it is determined that the tire type is determined when the profile corresponding to the tire type appearing in the running sound has a predetermined shape. More specifically, in the frequency characteristics, there are cases where no peak appears in the frequency band corresponding to the type of tire (when the peak is small and the peak cannot be specified), or when the peak width is wider than a predetermined reference. Can be mentioned. Of course, characteristics other than the profile shape, for example, a configuration in which the speed dependency of the profile is known and the tire type cannot be determined when the speed dependency is not reproduced may be adopted.

  Furthermore, another example of the specific condition is that the road surface is rougher than a predetermined state. That is, the component corresponding to the type of tire included in the running sound becomes clearer as the road surface becomes flat, and becomes unclear as the road surface becomes rougher. Therefore, if the road surface is flatter than a predetermined state, It is possible to determine the tire type with high accuracy by the running sound of the tire, and if the road surface is rougher than the predetermined state, it is considered that the tire type cannot be determined with high accuracy by the running sound on the road surface before processing. Can do.

  In the predetermined state, when the road surface is rougher than the predetermined state, the tire type cannot be determined based on the running sound of the vehicle traveling on the road surface, or the determination reliability is predetermined. What is necessary is just to be previously defined as a state which becomes below reliability. Various indices can be adopted as an index for evaluating the roughness of the road surface, and examples thereof include MPD (Mean Profile Depth). The MPD can be measured by a CT meter (Circular Texture meter) or the like. When a predetermined state is defined by MPD, it can be defined by various values. For example, when MPD is 0.4 or more, a configuration for processing a road surface or the like can be adopted.

  Although the case where the present invention is realized as a system has been described above, the present invention can be realized as a method for realizing such a system. In addition, the tire determination system as described above may be realized alone, applied to a certain method, or used in a state where the method is incorporated in another device. However, the present invention is not limited to this and includes various modes. In addition, the implementation mode can be changed as appropriate, such as software or hardware. The software recording medium may be a magnetic recording medium, a magneto-optical recording medium, or any recording medium to be developed in the future.

(1A) is a diagram showing a tread pattern of a summer tire, (1B) is a diagram showing a tread pattern of a winter tire, and (1C) is a graph showing frequency characteristics of a running sound of a vehicle. (2A) and (2B) are graphs showing the frequency characteristics of the running sound of the vehicle. (3A) and (3B) are graphs showing the frequency characteristics of the running sound of the vehicle. It is a figure which shows the relationship between MPD which shows the roughness of a road surface, and the clarity of a pattern excitation sound. It is a block diagram which shows one Embodiment of this invention. It is a flowchart which shows a tire determination process. It is a figure for demonstrating the running sound which generate | occur | produces from the vehicle in driving | running | working. It is a flowchart which shows a tire determination process.

Here, embodiments of the present invention will be described in the following order.
(1) Principle of tire judgment:
(2) Configuration of tire determination system and tire determination processing:
(3) Other embodiments:

(1) Principle of tire judgment:
FIG. 7 shows the main components of the running sound of the vehicle, and the tire road noise that occupies most of the running sound of the vehicle is mainly composed of the pattern main groove resonance sound and the pattern excitation sound. It has been. When comparing the pattern main groove resonance sound and the pattern vibration sound between the summer tire and the winter tire, the ratio of each component in the noise is different due to the difference in the tread pattern. That is, the summer tire has a larger pattern main groove resonance sound component generated from the air column tube formed by the rib pattern and the road surface in the ground contact portion, and the winter tire is caused by the impact when the tire surface block contacts the road surface. The pattern excitation sound component which is a sound becomes large.

  Here, it demonstrates in detail with reference to FIG. 1A. FIG. 1A is a diagram showing a tread pattern of a typical summer tire. As shown in FIG. 1A, in a summer tire, a tread pattern is formed by a rib pattern Gr extending along a circumference centering on the rotation axis A of the tire and a lag pattern Gl intersecting the rib pattern Gr. . In the tread pattern of the summer tire, as shown in FIG. 1A, the rib pattern Gr is formed wider and deeper than the lug pattern Gl, and the pattern main groove resonance component generated due to the rib pattern Gr. The ratio of increases.

なお、式（１）において、ｆはパターン主溝共鳴音の周波数（Ｈｚ）、ｃは音速（ｍ／ｓ）、Ｌは接地部分のリブパターンＧｒの長さ（ｍ）、αは開口端補正である。式（１）に示すように、パターン主溝共鳴音の周波数は、音速およびリブパターンＧｒの長さに依存しているが、車両の車速や車種等に依存せずほぼ一定の周波数となる。そして、音速およびリブパターンＧｒの長さが環境や車種等によって多少変動するとしてもその変動は小さく、式（１）の周波数はほぼ一定の範囲に含まれるとみなすことができ、その周波数は８００Ｈｚ〜１０００Ｈｚ程度の周波数域になる。 Here, the pattern main groove resonance is a frequency characteristic represented by the following formula (1).

In equation (1), f is the frequency (Hz) of the pattern main groove resonance, c is the speed of sound (m / s), L is the length (m) of the rib pattern Gr of the ground contact portion, and α is the open end correction. It is. As shown in Expression (1), the frequency of the pattern main groove resonance sound depends on the speed of sound and the length of the rib pattern Gr, but is almost constant regardless of the vehicle speed, the vehicle type, or the like. Even if the speed of sound and the length of the rib pattern Gr slightly vary depending on the environment, vehicle type, etc., the variation is small, and the frequency of equation (1) can be considered to be included in a substantially constant range, and the frequency is 800 Hz. It becomes a frequency range of about ~ 1000 Hz.

  FIG. 1C is a graph showing the frequency characteristics when the running sound of a vehicle running at 40 km / h is measured, the vertical axis represents the intensity of the running sound, and the horizontal axis represents the logarithm of the frequency. Here, normalization is performed in all frequency ranges so that the integrated value of the intensity of the running sound is 1. In the graph shown in FIG. 1C, the characteristic indicated by the solid line is the frequency characteristic of the running sound intensity of the summer tire, and the characteristic indicated by the broken line is the frequency characteristic of the intensity of the running sound of the winter tire. As described above, when the frequency characteristic obtained by actually measuring the intensity of the running sound of the vehicle equipped with the summer tire is analyzed, it was confirmed that the peak frequency appears at 1000 Hz which is the frequency of the pattern main groove resonance sound. Therefore, if a frequency range in which the pattern main groove resonance sound appears is defined in advance, it is determined that a summer tire is mounted on the vehicle when the peak frequency of the traveling sound intensity is included in the frequency range. Is possible. In addition, when the peak frequency of the traveling sound intensity is not included in the frequency range, it can be determined that the winter tire is mounted on the vehicle.

  On the other hand, FIG. 1B is a view showing a tread pattern of a typical winter tire. As shown in FIG. 1B, in a winter tire, a plurality of blocks B surrounded by a groove Gr extending along a circumference centering on the rotation axis A of the tire and a groove Gl intersecting the groove are arranged. Thus, a tread pattern is formed. And in the tread pattern of a winter tire, as shown to FIG. 1B, the width | variety of the groove | channel Gr and the groove | channel Gl is approximating, and the depth is also approximating. Furthermore, the groove Gl of the winter tire is wider and deeper than the lug pattern Gl of the summer tire. Therefore, the ratio of the pattern excitation sound component generated due to the block B is increased in the running sound of the vehicle equipped with the winter tire.

なお、式（２）において、ｆはパターン加振音の周波数（Ｈｚ）、Ｖは車両の車速（ｋｍ／ｈ）、ｎは周方向のブロックＢの個数、Ｒはタイヤの半径（ｍ）である。式（２）に示すように、パターン加振音の周波数は、車両の車速に依存し、車速が小さいほど低い周波数となる。例えば、車速＝４０ｋｍ／ｈ、ｎ＝６０、Ｒ＝０．２７ｍ程度の状態を想定すると、パターン加振音の周波数は４００Ｈｚ程度の周波数域になり、車速以外の値を固定するとパターン加振音の周波数は車速に比例する。また、車速３０ｋｍ／ｈ、５０ｋｍ／ｈ程度の状態を想定すると、パターン加振音の周波数はそれぞれ３００Ｈｚ，５００Ｈｚ程度の周波数域になる。 Here, the frequency characteristics of the pattern excitation sound are as shown in the following equation (2).

In equation (2), f is the frequency (Hz) of the pattern excitation sound, V is the vehicle speed (km / h), n is the number of blocks B in the circumferential direction, and R is the tire radius (m). is there. As shown in Equation (2), the frequency of the pattern excitation sound depends on the vehicle speed of the vehicle, and becomes lower as the vehicle speed is lower. For example, assuming a state where the vehicle speed is 40 km / h, n = 60, and R = 0.27 m, the frequency of the pattern excitation sound is in the frequency range of about 400 Hz, and if a value other than the vehicle speed is fixed, the pattern excitation sound The frequency of is proportional to the vehicle speed. Further, assuming a state where the vehicle speed is about 30 km / h and 50 km / h, the frequency of the pattern excitation sound is in a frequency range of about 300 Hz and 500 Hz, respectively.

  FIG. 1C is a graph of the running sound of the vehicle running at 40 km / h, as described above, and FIGS. 2A and 2B measure the running sound of the vehicle running at 30 km / h and 50 km / h. Is a graph showing frequency characteristics with the sound intensity of the traveling sound and the horizontal axis representing the logarithm of the frequency. In this case as well, standardization is performed in the entire frequency range so that the integrated value of the intensity of the running sound is 1. As shown in these graphs, when the frequency characteristics obtained by measuring the intensity of the traveling sound of a vehicle traveling at 30 km / h, 40 km / h, 50 km / h with winter tires are analyzed, It was confirmed that the peak frequency appears in the vicinity of 300 Hz, 400 Hz, and 500 Hz, and it was confirmed that the peak frequency depends on the vehicle speed.

  Therefore, if the frequency range in which the pattern excitation sound appears is defined in advance, it can be determined that the vehicle is equipped with a winter tire when the peak frequency of the intensity of the running sound is included in the frequency range. It becomes possible. Further, when a peak does not appear in the frequency range where the pattern excitation sound appears, it can be determined that the summer tire is attached to the vehicle. Furthermore, when the peak frequency existing in the frequency range where the pattern excitation sound appears depends on the vehicle speed of the vehicle, it can be determined that the winter tire is mounted on the vehicle.

  As described above, when the frequency of the running sound is analyzed by paying attention to the peak frequency of the pattern main groove resonance sound or the pattern excitation sound, the type of tire that the vehicle is wearing can be determined. However, there are various environments in which the vehicle travels, and various noises can be included in the traveling sound. That is, as shown in FIG. 7, the tire road noise includes a pattern sound depending on the tire pattern (pattern main groove resonance sound, pattern excitation sound) and a sound other than the pattern independent pattern (ground friction vibration sound, road Excitation sound due to unevenness, air pumping sound due to road gaps, etc.) exist, and sound other than the pattern becomes noise when analyzing the pattern sound.

  FIGS. 3A and 3B show frequency characteristics of running sound when a vehicle equipped with winter tires runs on a road surface at 40 km / h, 50 km / h, and 60 km / h. FIG. 3A shows a flat road surface, FIG. 3B has shown about the case where it drive | worked the road surface rougher than the said road surface. 3A and 3B also show the frequency characteristics with the vertical axis representing the traveling sound intensity and the horizontal axis representing the logarithm of the frequency, and the frequency characteristics are normalized so that the integrated value of the traveling sound intensity is 1. ing. Moreover, it is a running sound in case a solid line is 40 km / h, a dashed-dotted line is 50 km / h, and a broken line is 60 km / h.

  In the vehicle in which these traveling sounds are measured, the peak frequency of the pattern excitation sound when traveling at 40 km / h is about 430 Hz, and the peak frequency of the pattern excitation sound when traveling at 50 km / h is about 530 Hz, 60 km. The peak frequency of the pattern excitation sound when traveling at / h is about 630 Hz. Therefore, as shown in FIG. 3A, the peak frequency of the pattern excitation sound clearly appears on a flat road surface, and it is clear that the peak frequency depends on the vehicle speed of the vehicle. On the other hand, as shown in FIG. 3B, since the noise component becomes relatively large on a rough road surface, the peak frequency of the pattern excitation sound is unclear and the peak frequency depends on the vehicle speed. It becomes unclear.

  FIG. 4 is a diagram showing the relationship between MPD indicating the roughness of the road surface and the clarity of the pattern excitation sound, where the horizontal axis indicates MPD and the vertical axis indicates the clarity of the pattern excitation sound. MPD is a value obtained by measuring a road surface on which a vehicle travels with a CT meter. The intelligibility of the pattern excitation sound is an index for evaluating the peak size and sharpness of the pattern excitation sound. Based on the peak width and size, (peak size / peak width) × (peak size) This is the value calculated by The magnitude of the peak is a value of intensity at the peak frequency, and the width of the peak is, for example, a half width. The index increases as the peak size increases, and increases as the peak width decreases. Therefore, the index has a larger value as the peak profile of the pattern excitation sound is larger and sharper (that is, the peak is clearer).

  In FIG. 4, the clarity of the pattern excitation sound when traveling sound is measured on different road surfaces is plotted with black circles against MPD, and the approximate straight line indicating the change of each point is indicated by a solid line. As shown in FIG. 4, the clarity of the pattern excitation sound increases as the MPD decreases. Therefore, the pattern excitation sound can be measured more clearly as the road surface is flatter. Therefore, in the present embodiment, when the road surface is rougher than a predetermined state, a process for flattening the road surface is performed on the road surface, and a traveling sound when the vehicle travels on the processed road surface that has been processed. By obtaining and analyzing, the type of tire is determined. According to this configuration, the presence / absence (or speed dependency) of the pattern excitation sound can be clearly specified, and the type of tire can be determined with high accuracy.

(2) Configuration of tire determination system and tire determination processing:
FIG. 5 is a block diagram showing an embodiment of the tire determination system of the present invention, and FIG. 6 is a flowchart showing a tire determination process executed by the tire determination system. Various devices can be connected to the tire determination system 10 according to the present embodiment via an interface (not shown). In the present embodiment, an amplifier 41 and a display unit 42 are connected to the tire determination system 10. A microphone 40 is connected to the amplifier 41.

  The tire determination system 10 includes a control unit 20 and a recording medium 30. The control unit 20 includes a CPU, RAM, ROM, and the like (not shown), and can execute a program recorded in the recording medium 30 or the ROM. In the present embodiment, the tire determination program 21 can be executed as one of the programs. In addition, frequency information 30a indicating the frequency range of the pattern excitation sound is recorded in the recording medium 30 in advance.

  The tire determination program 21 includes a traveling sound acquisition unit 21a and a tire determination unit 21b. The traveling sound acquisition unit 21a is a module that causes the control unit 20 to realize a function of acquiring the traveling sound of the vehicle. However, in this embodiment, it is determined whether or not processing is performed according to the roughness of the existing road surface. Therefore, in this embodiment, as shown in FIG. 6, it is first determined whether or not the MPD of the road surface before processing is 0.4 or more (step S102), and the MPD of the road surface is 0.4 or more. When the road surface is, the road surface is processed (step S104), and when the road surface MPD is not 0.4 or more, the road surface is not processed (step S104 is skipped).

Here, as shown in FIG. 4, when MPD is smaller than 0.4, the clarity of the pattern excitation sound is sufficiently large, and the tire type can be accurately determined based on the pattern excitation sound. It is assumed that processing can be performed, and processing is performed when MPD is 0.4 or more. In step S104, the existing road surface may be processed to flatten the existing road surface to obtain a processed road surface, but the MPD is processed to be smaller than 0.4. It is preferable. As a recent technique for realizing such processing, there is a configuration in which a processed road surface is formed by fine grain pavement or color pavement. FIG. 5 shows an example in which the processed road surface Rm is formed by processing the road surface R. However, when step S104 is skipped in the process shown in FIG. Without being formed, the vehicle travels on the road surface R.

  After the processing as described above, the control unit 20 acquires the traveling sound of the vehicle by the processing of the traveling sound acquisition unit 21a (step S106). That is, the microphone 40 is installed at a position where the traveling sound of the vehicle traveling on the processed road surface Rm (or the road surface R) can be acquired, and the traveling sound of the vehicle is displayed when the vehicle travels around the microphone 40. A signal is output from the microphone 40. When a signal indicating running sound is output from the microphone 40, the signal is amplified by the amplifier 41. When the amplified signal is output from the amplifier 41, the control unit 20 acquires the amplified signal by the processing of the traveling sound acquisition unit 21a.

  The tire determination unit 21b is a module that causes the control unit 20 to realize a function of determining whether the type of tire mounted on the vehicle is a summer tire or a winter tire based on the frequency characteristics of traveling sound. In the present embodiment, the control unit 20 performs a frequency analysis of the running sound of the vehicle and acquires a frequency characteristic of the intensity of the running sound by the processing of the tire determination unit 21b (step S110). That is, the correspondence relationship between the intensity of the traveling sound of the vehicle and the frequency is acquired.

  Next, the control part 20 specifies the peak frequency of the intensity | strength of driving | running | working sound in the frequency range (for example, 200Hz-600Hz) where the peak frequency of pattern excitation sound exists by the process of the tire determination part 21b (step S120). ). That is, the control unit 20 specifies a profile in which a maximum value exists in the intensity of traveling sound and the intensity tends to decrease in a band where the frequency is higher and lower than the maximum value. For example, the peak frequency is specified such that the clarity of the pattern excitation sound shown in FIG. 4 is a predetermined value (for example, 0.5 or 0.6).

  Next, the control unit 20 determines whether or not the peak frequency is included in the frequency range of the pattern excitation sound by the processing of the tire determination unit 21b (step S130). That is, the control unit 20 refers to the frequency information 30a recorded on the recording medium 30, and determines whether the peak frequency of the intensity of the running sound of the vehicle is included in the frequency range of the pattern excitation sound indicated by the frequency information 30a. Determine.

  In step S130, when it is not determined that the peak frequency is included in the frequency range of the pattern excitation sound, the control unit 20 determines that the summer tire is mounted on the vehicle by the processing of the tire determination unit 21b, and displays it. A control signal is output to the unit 42 to display the determination result on the display unit 42 (step S140). On the other hand, when it is determined in step S130 that the peak frequency is included in the frequency range of the pattern excitation sound, the control unit 20 determines that a winter tire is mounted on the vehicle by the processing of the tire determination unit 21b. And a control signal is output with respect to the display part 42, and the said determination result is displayed on the display part 42 (step S150). According to the above processing, it is possible to automatically and accurately determine the type of tire without relying on visual observation.

(3) Other embodiments:
The above embodiment is an example for carrying out the present invention, and various other embodiments can be adopted as long as the type of tire mounted on the vehicle is determined based on the running sound of the vehicle. For example, the tread pattern of the tire shown in FIGS. 1A and 1B is an example, and the ratio of the pattern main groove resonance sound component is large in the summer tire regardless of the tread pattern, and the pattern vibration sound component of the winter tire is large. The type of tire can be determined using the fact that the ratio is large.

  Further, as shown in FIGS. 1C, 2A, and 2B, it is also possible to determine the type of tire using the fact that the pattern excitation sound depends on the vehicle speed of the vehicle and the pattern main groove resonance sound does not depend on the vehicle speed of the vehicle. It is. In the embodiment using the vehicle speed dependency of the pattern excitation sound as described above, for example, in the configuration shown in FIG. 5, the frequency information 30a is omitted and the traveling sound of the vehicle traveling on the processed road surface (or road surface R) is obtained. This can be realized by installing a plurality of microphones at a plurality of positions where the signal can be obtained and executing the flowchart shown in FIG. Note that in this embodiment, the vehicle speed at each position changes by applying a paint having a visual effect that causes unevenness on the road surface or inducing acceleration / deceleration between the positions where the microphones are installed. To be configured.

  In the process shown in FIG. 8, step S202 and step S204 are the same as step S102 and step S104 described above. When the vehicle travels on the processed road surface Rm (or road surface R), the control unit 20 is the same at each of the n positions (n is an integer of 2 or more) where the microphones are installed by the processing of the traveling sound acquisition unit 21a. The traveling sound of the vehicle is acquired (step S206). Next, the control unit 20 performs frequency analysis on the traveling sound at each of the n positions by the processing of the tire determination unit 21b, and acquires the frequency characteristics of the traveling sound intensity for each position (step S210).

  Next, the control part 20 specifies the peak frequency of the intensity | strength of driving | running | working sound for every position by the process of the tire determination part 21b (step S220). Here, the peak frequency of each of the n positions is expressed as f (n). Next, the control unit 20 determines whether or not the peak frequency f (n) for each position matches by the processing of the tire determination unit 21b (step S230). That is, it is determined whether or not f (1) ≠ f (2)... ≠ f (n). If f (1) ≠ f (2). The frequency is assumed to be speed dependent.

  And in step S230, when it determines with the peak frequency f (n) for every position agree | coinciding, the control part 20 determines with the process of the tire determination part 21b having mounted | worn with the summer tire in the vehicle, A control signal is output to the display unit 42 to display the determination result on the display unit 42 (step S240). Of course, it is possible to determine whether or not the peak frequencies f (n) for each position coincide with each other by providing a margin corresponding to the measurement error and the fluctuation range of the pattern main groove resonance. On the other hand, if it is not determined in step S230 that the peak frequencies f (n) for each position match, the control unit 20 determines that a winter tire is mounted on the vehicle by the processing of the tire determination unit 21b, and displays. A control signal is output to the unit 42 to display the determination result on the display unit 42 (step S250). According to the above processing, it is possible to automatically determine the type of tire without relying on visual observation.

  In step S230, it is determined whether or not the peak frequency f (n) for each position matches. Of course, the peak frequency f (n) for each position changes according to the vehicle speed. The configuration may be such that the peak frequency decreases as the vehicle speed decreases.

  Furthermore, the type of tire may be determined using the fact that the pattern main groove resonance component increases in the running sound of a vehicle equipped with a summer tire. In this case, in the same configuration as the configuration shown in FIG. 5 described above, frequency information 30a indicating the frequency range of the pattern main groove resonance is recorded on the recording medium 30 in advance. In the same process as the process shown in FIG. 6, it is determined in step S130 whether or not the peak frequency is included in the frequency range of the pattern main groove resonance sound (step S130). That is, the control unit 20 refers to the frequency information 30a recorded on the recording medium 30, and whether or not the peak frequency of the intensity of the running sound of the vehicle is included in the frequency range of the pattern main groove resonance sound indicated by the frequency information 30a. Determine whether.

  When it is determined in step S130 that the peak frequency is included in the frequency range of the pattern main groove resonance, the control unit 20 determines that the summer tire is mounted on the vehicle by the processing of the tire determination unit 21b. Determination is made, and a control signal is output to the display unit 42 to display the determination result on the display unit 42. On the other hand, when it is not determined in step S130 that the peak frequency is included in the frequency range of the pattern main groove resonance, the control unit 20 determines that a winter tire is mounted on the vehicle by the processing of the tire determination unit 21b. Then, a control signal is output to the display unit 42 and the determination result is displayed on the display unit 42.

  Furthermore, in the above-described embodiment, the threshold value for determining whether or not to process the road surface is MPD = 0.4, but this threshold value is an example, and when the MPD of the road surface is a value equal to or larger than the threshold value. Various other values can be employed as long as the accuracy of determination of the type of tire is improved by processing. For example, if MPD = 0.6 is set as a threshold value, the road surface to be processed can be reduced as compared with the case where MPD = 0.4 is set as a threshold value, and the operation cost of the system can be suppressed.

  Furthermore, in order to determine whether or not to process, it is only necessary to be able to determine whether or not the road surface is rougher than a predetermined state, and various configurations are employed in addition to a configuration using a digitized index. Is possible. For example, it may be configured to determine whether or not processing is performed according to the type of road surface. More specifically, road surface flatness, tire type determination accuracy, and the like are specified in advance for each known pavement. . The existing road surface may be processed when the road surface has low flatness or the road surface has low accuracy in determining the type of tire, and the existing road surface is flatter than fine pavement or color pavement. When the road surface is low, it is possible to adopt a configuration in which a processed road surface is formed by fine pavement or color pavement.

  Furthermore, it is good also as a structure which tries measurement and determines whether it processes according to the measurement result obtained by trial. For example, the traveling sound of a vehicle traveling on the existing road surface R in the configuration shown in FIG. 5 is acquired, and the clarity of the peak of the pattern excitation sound and the pattern main groove resonance sound is evaluated based on the acquired traveling sound. . And it is good also as a structure which acquires the driving | running | working sound of the vehicle which drive | worked the processed road surface by processing a road surface when clarity is below a predetermined value, and drive | worked on the processed road surface.

DESCRIPTION OF SYMBOLS 10 ... Tire determination system, 20 ... Control part, 21 ... Tire determination program, 21a ... Running sound acquisition part, 21b ... Tire determination part, 30 ... Recording medium, 30a ... Frequency information, 40 ... Microphone, 41 ... Amplifier, 42 ... Display section

Claims (5)

Traveling sound acquisition means for acquiring the traveling sound by a microphone installed in a traveling sound measurement section of a vehicle traveling on a processed road surface that has been processed to flatten the road surface with respect to a road surface;
Tire determining means for determining the type of tire mounted on the vehicle based on a pattern sound included in the traveling sound;
A tire determination system comprising:   The processed road surface is a road surface whose MPD indicating the roughness of the road surface is smaller than 0.6.
The tire determination system according to claim 1.   The processed road surface is a road surface whose MPD indicating the roughness of the road surface is smaller than 0.4.
The tire determination system according to claim 1.   A travel sound acquisition step of acquiring the travel sound by a microphone installed in a travel sound measurement section of a vehicle traveling on a processed road surface that has been processed to flatten the road surface with respect to a road surface;
  A tire determination step of determining the type of tire mounted on the vehicle based on a pattern sound included in the traveling sound;
The tire judgment method containing.   In the running sound acquisition step,
    The road surface is processed to be the processed road surface when the type of tire attached to the vehicle cannot be determined based on the traveling sound of the vehicle traveling on the road surface.
The tire determination method according to claim 4.

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