Analysis device, analysis method, and program

Abstract

This analysis device comprises: a sound absorption rate calculation unit that calculates a sound absorption rate on the basis of design information of a sound absorption structure; a modeling unit that generates a finite element model on the basis of design information of a tire; a sound absorption rate setting unit that sets a sound absorption boundary having a sound absorption rate to a finite element model on the basis of arrangement information of the sound absorption structure with respect to the tire; and a sound pressure analysis unit that analyzes a sound pressure distribution of an internal space of the tire on the basis of the finite element model in which the sound absorption boundary is set.

Description

Analysis device, analysis method, and program

[0001] The present disclosure relates to an analysis device, an analysis method, and a program.

[0002] A technique is known in which a sound-absorbing structure is disposed in a tire attached to a vehicle such as an automobile to reduce resonance noise generated inside the tire while the vehicle is running. Also known is a technique for analyzing the sound-absorbing effect of the design and arrangement of a sound-absorbing structure by numerical analysis such as the finite element method. For example, Non-Patent Document 1 discloses a technique for analyzing the sound pressure distribution inside a tire when a sound-absorbing structure using a Helmholtz resonator is installed, based on the finite element method.

[0003] Yukito Nakano, Nao Tomita, Makoto Seki, Takuya Nishimura, "Reduction of Ear-Level Noise During Low-Speed ​​Driving of EVs Using a Pulp-Molded Helmholtz Resonator," Transactions of the Japan Society of Mechanical Engineers, Vol. 88, No. 911, 2022

[0004] However, in conventional technologies, the sound pressure level in the space inside a tire is calculated based on a finite element model that includes the structure of the sound-absorbing structure installed in the tire, which requires a large amount of calculation to analyze the sound pressure distribution.In addition, when the design or layout of the sound-absorbing structure is changed, a new finite element model must be constructed each time, making it difficult to compare the sound-absorbing effects of various designs or layouts of sound-absorbing structures.

[0005] An object of one aspect of the present disclosure is to efficiently analyze the sound pressure distribution in the internal space of a tire in which a sound-absorbing structure is installed.

[0006] The present disclosure has the following configuration.

[0007] [1] An analysis device comprising: a sound absorption coefficient calculation unit configured to calculate a sound absorption coefficient based on design information of a sound absorbing structure; a modeling unit configured to generate a finite element model based on design information of a tire; a sound absorption coefficient setting unit configured to set a sound absorbing boundary having the sound absorption coefficient in the finite element model based on arrangement information of the sound absorbing structure with respect to the tire; and a sound pressure analysis unit configured to analyze the sound pressure distribution in the internal space of the tire based on the finite element model in which the sound absorbing boundary has been set.

[0008] [2] The analysis device according to the above [1], wherein the sound pressure analysis unit is configured to analyze the sound pressure distribution in the internal space of the tire by a coupled analysis of vibration analysis and acoustic analysis.

[0009] [3] The analysis device according to [2] above, wherein the sound pressure analysis unit is configured to analyze a plurality of sound pressure distributions having different positional relationships between the vibration position and the sound absorbing boundary.

[0010] [4] The analysis device according to [3] above, wherein the sound pressure analysis unit is configured to analyze the sound pressure distribution for each rotation angle when the position of the sound absorbing boundary is rotated by a predetermined rotation angle while the vibration position is fixed.

[0011] [5] The analysis device according to [4] above, further comprising a result output unit configured to output an analysis result including the sound pressure distribution for each rotation angle and a maximum value of the sound pressure level for each sound pressure distribution.

[0012] [6] The analysis device according to any one of [1] to [5] above, further comprising: a design acquisition unit configured to acquire design information of the sound absorbing structure and design information of the tire; and a condition presentation unit configured to output a sound absorption coefficient curve based on the design information of the sound absorbing structure and a resonance frequency based on the design information of the tire.

[0013] [7] The analysis device according to [6] above, wherein the condition presentation unit is configured to accept adjustments to design information of the sound absorbing structure.

[0014] [8] The analysis device according to any one of [1] to [7] above, wherein the sound absorbing structure is a Helmholtz resonator with an embedded neck, and is disposed on the inner surface of the tread portion of the tire.

[0015] [9] An analysis method in which a computer executes the following steps: calculating a sound absorption coefficient based on design information of a sound absorbing structure; generating a finite element model based on design information of a tire; setting a sound absorbing boundary having the sound absorption coefficient in the finite element model based on arrangement information of the sound absorbing structure with respect to the tire; and analyzing the sound pressure distribution in the internal space of the tire based on the finite element model in which the sound absorbing boundary has been set.

[0016]

[10] A program for causing a computer to execute the following steps: calculating a sound absorption coefficient based on design information of a sound absorbing structure; generating a finite element model based on design information of a tire; setting a sound absorbing boundary having the sound absorption coefficient in the finite element model based on arrangement information of the sound absorbing structure with respect to the tire; and analyzing the sound pressure distribution in the internal space of the tire based on the finite element model in which the sound absorbing boundary has been set.

[0017] According to one aspect of the present disclosure, it is possible to efficiently analyze the sound pressure distribution in the internal space of a tire in which a sound absorbing structure is installed.

[0018] FIG. 1 is a block diagram showing an example of the overall configuration of an analysis system. FIG. 2 is a block diagram showing an example of the hardware configuration of a computer. FIG. 3 is a block diagram showing an example of the functional configuration of the analysis system. FIG. 4 is a diagram for explaining an example of tire design information. FIG. 5 is a diagram for explaining an example of design information for a sound absorbing structure. FIG. 6 is a diagram for explaining an example of arrangement information for a sound absorbing structure. FIG. 7 is a flowchart showing an example of an analysis method. FIG. 8 is a diagram showing an example of an analysis condition screen. FIG. 9 is a diagram showing an example of an analysis result screen.

[0019] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0020] [Embodiment] One embodiment of the present disclosure is an analysis system that analyzes sound pressure distribution in the internal space of a tire in which a sound-absorbing structure is disposed. In this embodiment, the sound-absorbing structure may be an embedded Helmholtz resonator. The Helmholtz resonator is a structure that includes a hollow member having an opening and a neck portion connected to extend the length of the opening. The embedded Helmholtz resonator is a Helmholtz resonator in which the extension of the opening by the neck portion is located inside the hollow member.

[0021] When a vehicle is running, a resonance noise, also known as air column resonance, is generated inside the tires. The air column resonance has a resonance frequency that depends on the tire shape. For example, in a passenger car, the resonance frequency is approximately 200 Hz, generating a noise also known as road noise.

[0022] By placing a sound-absorbing structure designed to exhibit high sound-absorbing properties at the tire's resonance frequency inside the tire, it is possible to suppress the air column resonance noise generated inside the tire while the vehicle is running. The more sound-absorbing structures placed in a tire, the better the sound-absorbing performance, but the tire's weight increases, which may affect the vehicle's running. In addition, adding sound-absorbing structures to a tire also increases manufacturing costs. Therefore, when placing sound-absorbing structures in a tire, it is necessary to consider an appropriate design and placement, taking into account the balance of factors such as weight, shape, installation intervals, installation cost, and sound-absorbing effect.

[0023] The purpose of this embodiment is to efficiently analyze the sound pressure distribution in the internal space of a tire that has a sound absorbing structure installed. To this end, this embodiment sets a sound absorbing boundary having a sound absorption coefficient calculated based on the design information of the sound absorbing structure in a finite element model constructed based on the design information of the tire, and analyzes the sound pressure distribution in the internal space of the tire based on the finite element model in which the sound absorbing boundary is set.

[0024] In one aspect, according to this embodiment, since the structure of the sound absorbing structure is not included in the finite element model, analysis of sound pressure distribution based on the finite element model can be performed with a small amount of calculation. In another aspect, according to this embodiment, since the sound pressure distribution in the internal space of a tire when sound absorbing structures are installed in various designs and arrangements can be analyzed in a short time, optimal design and arrangement of the sound absorbing structure can be efficiently designed.

[0025] <Overall Configuration> The overall configuration of the analysis system in this embodiment will be described with reference to Fig. 1. Fig. 1 is a block diagram showing an example of the overall configuration of the analysis system.

[0026] 1, analysis system 1000 includes analysis device 10 and terminal device 20. Analysis device 10 and terminal device 20 are connected to each other so as to be able to communicate data with each other via a communication network N such as a local area network (LAN) or the Internet.

[0027] The analysis device 10 is an example of an information processing device such as a personal computer, workstation, or server that analyzes the sound pressure distribution in the space inside a tire in which a sound absorbing structure is installed. The analysis device 10 receives design data indicating the shapes of the tire and the sound absorbing structure from the terminal device 20, and analyzes the sound pressure distribution in the space inside the tire in which the sound absorbing structure is installed. The analysis device 10 transmits the analysis results of the sound pressure distribution in the space inside the tire to the terminal device 20.

[0028] The terminal device 20 is an example of an information processing terminal such as a personal computer, a smartphone, or a tablet terminal operated by a user of the analysis system 1000. The terminal device 20 transmits design data specified by the user to the analysis device 10. The terminal device 20 receives analysis results from the analysis device 10 and presents them to the user.

[0029] The overall configuration of the analysis system 1000 shown in FIG. 1 is an example, and various system configuration examples are possible depending on the application and purpose. For example, the analysis system 1000 may include multiple analysis devices 10 and one or more terminal devices 20. For example, the analysis device 10 may be realized by multiple computers, or may be realized as a cloud computing service. For example, the analysis device 10 may be realized by a standalone computer. The classification of devices such as the analysis device 10 and terminal device 20 shown in FIG. 1 is an example.

[0030] <Hardware Configuration> The hardware configuration of the analysis system 1000 will be described with reference to Fig. 2. The analysis device 10 and terminal device 20 included in the analysis system 1000 are realized by, for example, a computer. Fig. 2 is a block diagram showing an example of the hardware configuration of a computer.

[0031] 2, the computer 500 includes a CPU (Central Processing Unit) 501, a ROM (Read Only Memory) 502, a RAM (Random Access Memory) 503, a HDD (Hard Disk Drive) 504, an input device 505, a display device 506, a communication I / F (Interface) 507, and an external I / F 508. The CPU 501, the ROM 502, and the RAM 503 form a so-called computer. The hardware components of the computer 500 are connected to each other via a bus line 509. The input device 505 and the display device 506 may be connected to the external I / F 508 for use.

[0032] The CPU 501 is a computing device that reads programs and data from a storage device such as the ROM 502 or the HDD 504 onto the RAM 503 and executes processing to realize overall control and functions of the computer 500 .

[0033] The ROM 502 is an example of a non-volatile semiconductor memory (storage device) that can retain programs and data even when the power is turned off. The ROM 502 functions as a main storage device that stores various programs, data, etc. required for the CPU 501 to execute various programs installed in the HDD 504. Specifically, the ROM 502 stores boot programs such as a Basic Input / Output System (BIOS) and an Extensible Firmware Interface (EFI) that are executed when the computer 500 starts up, as well as data such as OS (Operating System) settings and network settings.

[0034] The RAM 503 is an example of a volatile semiconductor memory (storage device) in which programs and data are erased when the power is turned off. The RAM 503 is, for example, a dynamic random access memory (DRAM) or a static random access memory (SRAM). The RAM 503 provides a working area in which various programs installed in the HDD 504 are expanded when executed by the CPU 501.

[0035] The HDD 504 is an example of a non-volatile storage device that stores programs and data. The programs and data stored in the HDD 504 include an OS, which is basic software that controls the entire computer 500, and applications that provide various functions on the OS. Note that the computer 500 may use a storage device that uses flash memory as a storage medium (e.g., an SSD (Solid State Drive)) instead of the HDD 504.

[0036] The input device 505 includes a touch panel, operation keys and buttons, a keyboard and mouse, a microphone for inputting sound data such as voice, and the like, which are used by the user to input various signals.

[0037] The display device 506 is composed of a display such as a liquid crystal display or organic electroluminescence (EL) display for displaying a screen, a speaker for outputting sound data such as voice, and the like.

[0038] The communication I / F 507 is an interface that connects to a communication network and enables the computer 500 to perform data communication.

[0039] The external I / F 508 is an interface with external devices, such as a drive device 510.

[0040] The drive device 510 is a device for loading a recording medium 511. The recording medium 511 here includes media that record information optically, electrically, or magnetically, such as CD-ROMs, flexible disks, and magneto-optical disks. The recording medium 511 may also include semiconductor memories that record information electrically, such as ROMs and flash memories. This allows the computer 500 to read from and / or write to the recording medium 511 via the external I / F 508.

[0041] The various programs to be installed in the HDD 504 are installed, for example, by setting the distributed recording medium 511 in a drive device 510 connected to the external I / F 508 and reading the various programs recorded on the recording medium 511 by the drive device 510. Alternatively, the various programs to be installed in the HDD 504 may be installed by being downloaded via the communication I / F 507 from a network different from the communication network.

[0042] <Functional Configuration> The functional configuration of the analysis device 10 will be described with reference to Fig. 3. Fig. 3 is a block diagram showing an example of the functional configuration of the analysis device.

[0043] As shown in FIG. 3 , the analysis device 10 includes a design acquisition unit 110, a modeling unit 120, a frequency calculation unit 130, a sound absorption coefficient calculation unit 140, a condition presentation unit 150, a sound absorption coefficient setting unit 160, a sound pressure analysis unit 170, and a result output unit 180.

[0044] The design acquisition unit 110, modeling unit 120, frequency calculation unit 130, sound absorption coefficient calculation unit 140, condition presentation unit 150, sound absorption coefficient setting unit 160, sound pressure analysis unit 170, and result output unit 180 are realized by processing that causes the CPU 501 to execute a program that is loaded from the HDD 504 shown in FIG. 2 onto the RAM 503.

[0045] The design acquisition unit 110 acquires design data. The design data includes tire design information, sound absorbing structure design information, and placement information indicating the position where the sound absorbing structure is to be installed relative to the tire. The design acquisition unit 110 may receive the design data from the terminal device 20. The design acquisition unit 110 may accept input of the design data via the input device 505 of the analysis device 10.

[0046] Fig. 4 is a diagram for explaining an example of tire design information. Fig. 4(A) is a side view of the tire T. Fig. 4(B) is a cross-sectional view of the tire T taken along line A-A in Fig. 4(A). As shown in Fig. 4, the design information of the tire T may include a tire width w1, a tire outer diameter r1, a tire inner diameter (rim diameter) r2, and a tire thickness t1.

[0047] Fig. 5 is a diagram illustrating an example of design information for a sound absorbing structure. Fig. 5(A) is a cross-sectional view of a buried Helmholtz resonator R, which is an example of a sound absorbing structure. Fig. 5(B) is a top view of the buried Helmholtz resonator R shown in Fig. 5(A). As shown in Fig. 5, the design information for the buried Helmholtz resonator R may include a resonant body outer radius r3, a resonant body inner length h1, a resonant body surface thickness t2, a buried neck length h2, a buried neck inner radius r4, and a buried neck thickness t3.

[0048] FIG. 6 is a diagram illustrating an example of the placement information of the sound absorbing structures. FIG. 6 is a side view of a tire T on which four sound absorbing structures R1 to R4 are installed at 45° intervals. As shown in FIG. 6, the installation positions of the sound absorbing structures R1 to R4 may be expressed by placement angles θ1 to θ4, with 0° being defined as vertically above the tire T. The placement information of the sound absorbing structures may include multiple placement angles θ1 to θ4 that indicate the installation positions of the multiple sound absorbing structures R1 to R4, respectively. The sound absorbing structures R1 to R4 are installed inside the tire T. The sound absorbing structures R1 to R4 may also be installed on the inner surface of the tread portion of the tire T.

[0049] The tire design information may include physical property information of the rubber, physical property information of the rim, and physical property information of the air. The physical property information of the rubber may include, for example, density, modulus of elasticity, and Poisson's ratio. The physical property information of the rim may include, for example, density, modulus of elasticity, and Poisson's ratio. The physical property information of the air may include, for example, density and speed of sound. The physical property information of the rubber, physical property information of the rim, and physical property information of the air may be stored in advance in a storage device such as the HDD 504 of the analysis device 10.

[0050] The modeling unit 120 generates a finite element model of the tire and the space inside the tire based on the tire shape information acquired by the design acquisition unit 110. Hereinafter, the finite element model of the tire and the space inside the tire will also be referred to as a "tire model."

[0051] The frequency calculation unit 130 calculates the resonance frequency of the space within the tire based on the tire model generated by the modeling unit 120. The frequency calculation unit 130 may calculate the resonance frequency by a coupled analysis of vibration analysis and acoustic analysis. The coupled analysis may use physical property information of the rubber, the rim, and the air.

[0052] Specifically, the frequency calculation unit 130 analyzes the resonant frequency of the air column resonance sound generated by tire vibration. As an example, the frequency calculation unit 130 applies a load vibration to a predetermined position of the tire model and calculates the sound pressure level at a predetermined evaluation surface. The position at which the load vibration is applied corresponds to the contact patch when the tire is mounted on a vehicle. The evaluation surface may be a cross section at a position opposite the vibration position across the tire rotation axis (i.e., a position rotated 180° from the vibration position). The frequency calculation unit 130 calculates the sound pressure level for each frequency by frequency-resolving the air column resonance sound at the evaluation surface. The frequency calculation unit 130 acquires the frequency at which the sound pressure level peaks as the resonant frequency.

[0053] The sound absorption coefficient calculation unit 140 calculates the sound absorption coefficient curve of the sound absorbing structure based on the design information of the sound absorbing structure acquired by the design acquisition unit 110. The sound absorption coefficient calculation unit 140 may calculate the sound absorption coefficient for each frequency based on the shape of the sound absorbing structure indicated in the design information of the sound absorbing structure, and generate a sound absorption coefficient curve that indicates the frequency characteristics of the sound absorption coefficient. The sound absorption coefficient calculation unit 140 may calculate acoustic impedance as an example of the sound absorption coefficient.

[0054] A method for calculating acoustic impedance based on the shape of a sound absorbing structure is disclosed, for example, in the following Reference 1. However, the method disclosed in Reference 1 is just one example, and any method may be used as long as it is capable of calculating acoustic impedance based on the shape of a sound absorbing structure.

[0055] [Reference 1] Sibo Huang, Xinsheng Fang, Xu Wang, Badreddine Assouar, Qian Cheng, Yong Li, "Acoustic perfect absorbers via Helmholtz resonators with embedded apertures", The Journal of the Acoustical Society of America, vol. 145, pp. 254-262, 2019.

[0056] The condition presenting unit 150 outputs the analysis conditions. The analysis conditions may include the resonance frequency calculated by the frequency calculation unit 130 and the sound absorption coefficient curve calculated by the sound absorption coefficient calculation unit 140. The condition presenting unit 150 may transmit an analysis condition screen displaying the analysis conditions to the terminal device 20. The condition presenting unit 150 may display the analysis condition screen displaying the analysis conditions on the display device 506 of the analysis device 10.

[0057] The analysis condition screen may display design information of the sound absorbing structure used to calculate the sound absorption coefficient curve. The condition presentation unit 150 may accept adjustments to the design information of the sound absorbing structure in response to a user's operation on the analysis condition screen. When the condition presentation unit 150 accepts the adjustments to the design information of the sound absorbing structure, the design acquisition unit 110 acquires design data including the design information of the sound absorbing structure after the adjustments.

[0058] The sound absorption coefficient setting unit 160 sets a sound absorbing boundary having the sound absorption coefficient calculated by the sound absorption coefficient calculation unit 140 in the tire model generated by the modeling unit 120 based on the placement information acquired by the design acquisition unit 110. The sound absorption coefficient setting unit 160 may identify a sound absorption coefficient corresponding to the resonance frequency calculated by the frequency calculation unit 130 based on the sound absorption coefficient curve calculated by the sound absorption coefficient calculation unit 140, and set a sound absorbing boundary having the sound absorption coefficient in the tire model. As an example, when embedded Helmholtz resonators are installed at each installation position indicated in the placement information, the sound absorption coefficient setting unit 160 may set an acoustic impedance corresponding to the resonance frequency in a region where the bottom surface facing the opening of the embedded Helmholtz resonator is located.

[0059] The sound absorption coefficient setting unit 160 may determine the area of ​​the sound absorbing boundary for which the sound absorption coefficient is to be set based on design information of the sound absorbing structure. As an example, the sound absorption coefficient setting unit 160 may calculate the area of ​​the sound absorbing boundary based on the outer radius r3 of the resonant body. The sound absorption coefficient setting unit 160 may adjust the area of ​​the sound absorbing boundary so that the sound absorption characteristics of the sound absorbing boundary match the sound absorption characteristics measured in an experiment.

[0060] The sound pressure analysis unit 170 analyzes the sound pressure distribution in the space inside the tire based on the tire model in which the sound absorbing boundaries have been set by the sound absorption coefficient setting unit 160. The sound pressure analysis unit 170 may analyze a plurality of sound pressure distributions with different positional relationships between the vibration position and the sound absorbing boundaries. For example, the sound pressure analysis unit 170 may analyze the sound pressure distribution for each rotation angle when the position of the sound absorbing boundary is rotated by a predetermined rotation angle while the vibration position is fixed.

[0061] The result output unit 180 outputs the analysis results obtained by the sound pressure analysis unit 170. The result output unit 180 transmits an analysis result screen displaying the analysis results to the terminal device 20. The result output unit 180 may display the analysis result screen displaying the analysis results on the display device 506 of the analysis device 10.

[0062] The analysis result includes the sound pressure distribution analyzed by the sound pressure analysis unit 170. The analysis result may include the sound pressure distribution for each rotation angle. The analysis result may include the maximum sound pressure level for each sound pressure distribution. In other words, the analysis result may include the maximum sound pressure level for each rotation angle.

[0063] <Processing Procedure> The analysis method executed by analysis system 1000 will be described with reference to Fig. 7. Fig. 7 is a flowchart showing an example of the analysis method.

[0064] In step S1, the terminal device 20 receives design data input by a user and transmits the received design data to the analysis device 10.

[0065] The analysis device 10 receives design data from the terminal device 20. The design acquisition unit 110 of the analysis device 10 acquires the received design data. The design acquisition unit 110 extracts tire design information from the design data and sends it to the modeling unit 120. The design acquisition unit 110 extracts design information and layout information of the sound absorbing structure from the design data and sends it to the sound absorption coefficient calculation unit 140.

[0066] In step S2, the modeling unit 120 of the analysis device 10 receives tire design information from the design acquisition unit 110. The modeling unit 120 generates a tire model based on the tire design information. The modeling unit 120 sends the tire model to the frequency calculation unit 130 and the sound absorption coefficient setting unit 160.

[0067] In step S3, the frequency calculation unit 130 of the analysis device 10 receives the tire model from the modeling unit 120. The frequency calculation unit 130 calculates the resonant frequency of the space inside the tire based on the tire model. The frequency calculation unit 130 sends the resonant frequency to the condition presentation unit 150 and the sound absorption coefficient setting unit 160.

[0068] In step S4, the sound absorption coefficient calculation unit 140 of the analysis device 10 receives design information and arrangement information of the sound absorbing structure from the design acquisition unit 110. The sound absorption coefficient calculation unit 140 generates a sound absorption coefficient curve of the sound absorbing structure based on the design information of the sound absorbing structure. The sound absorption coefficient calculation unit 140 sends the sound absorption coefficient curve of the sound absorbing structure to the condition presentation unit 150. The sound absorption coefficient calculation unit 140 also sends the sound absorption coefficient curve of the sound absorbing structure and arrangement information of the sound absorbing structure to the sound absorption coefficient setting unit 160.

[0069] In step S5, the condition presenting unit 150 of the analysis device 10 receives the resonance frequency from the frequency calculation unit 130. The condition presenting unit 150 also receives the sound absorption coefficient curve from the sound absorption coefficient calculation unit 140. The condition presenting unit 150 transmits an analysis condition screen including the resonance frequency and the sound absorption coefficient curve to the terminal device 20.

[0070] The terminal device 20 receives the analysis condition screen. The terminal device 20 displays the analysis condition screen on the display device 506. The user of the terminal device 20 may refer to the resonance frequency and sound absorption coefficient curve displayed on the analysis condition screen. The user of the terminal device 20 may adjust the design information of the sound absorbing structure on the analysis condition screen. The user of the terminal device 20 may also instruct an analysis based on the design conditions displayed on the analysis condition screen.

[0071] In step S6, the condition presenting unit 150 of the analysis device 10 determines whether or not to adjust the design information of the sound absorbing structure. The condition presenting unit 150 may determine to adjust the design information of the sound absorbing structure if the user adjusts the design information of the sound absorbing structure on the analysis condition screen. On the other hand, the condition presenting unit 150 may determine not to adjust the design information of the sound absorbing structure if the user instructs analysis based on the design conditions on the analysis condition screen.

[0072] If it is determined that the design information of the sound absorbing structure is to be adjusted (YES), the design acquisition unit 110 acquires the adjusted design information of the sound absorbing structure and returns the process to step S4. On the other hand, if it is determined that the design information of the sound absorbing structure is not to be adjusted (NO), the condition presentation unit 150 proceeds to step S7.

[0073] When the process returns to step S4, the sound absorption coefficient calculation unit 140 calculates the sound absorption coefficient curve of the sound absorbing structure based on the design information of the adjusted sound absorbing structure. The analysis device 10 then executes steps S5 and S6 again. In this way, the analysis device 10 repeatedly calculates the sound absorption coefficient curve and presents analysis conditions until the user issues an instruction to perform analysis.

[0074] In step S7, the sound absorption coefficient setting unit 160 of the analysis device 10 receives the tire model from the modeling unit 120. The sound absorption coefficient setting unit 160 also receives the resonant frequency from the frequency calculation unit 130. Furthermore, the sound absorption coefficient setting unit 160 receives the sound absorption coefficient curve and arrangement information of the sound absorbing structure from the sound absorption coefficient calculation unit 140.

[0075] The sound absorption coefficient setting unit 160 specifies the sound absorption coefficient corresponding to the resonance frequency based on the sound absorption coefficient curve. The sound absorption coefficient setting unit 160 sets sound absorbing boundaries having the specified sound absorption coefficient in the tire model based on the arrangement information of the sound absorbing structure. The sound absorption coefficient setting unit 160 sends the tire model in which the sound absorbing boundaries have been set to the sound pressure analysis unit 170.

[0076] In step S8, the sound pressure analysis unit 170 of the analysis device 10 receives the tire model in which the sound absorbing boundaries have been set from the sound absorption coefficient setting unit 160. The sound pressure analysis unit 170 analyzes the sound pressure distribution in the space inside the tire based on the tire model in which the sound absorbing boundaries have been set. Specifically, the sound pressure analysis unit 170 analyzes the sound pressure distribution for each rotation angle when the position of the sound absorbing boundary is rotated by a predetermined rotation angle while fixing the vibration position of the tire model. The sound pressure analysis unit 170 also acquires the maximum sound pressure level for each sound pressure distribution. The sound pressure analysis unit 170 sends the sound pressure distribution for each rotation angle and the maximum sound pressure level for each sound pressure distribution to the result output unit 180.

[0077] In step S9, the result output unit 180 of the analysis device 10 receives the sound pressure distribution for each rotation angle and the maximum sound pressure level for each sound pressure distribution from the sound pressure analysis unit 170. The result output unit 180 transmits an analysis result screen including the sound pressure distribution for each rotation angle and the maximum sound pressure level for each sound pressure distribution to the terminal device 20.

[0078] The terminal device 20 receives the analysis result screen. The terminal device 20 displays the analysis result screen on the display device 506. The user of the terminal device 20 may refer to the analysis results displayed on the analysis result screen. The user of the terminal device 20 may consider the placement of the sound absorbing structure relative to the tire or the design of the sound absorbing structure. The user of the terminal device 20 may change the placement information of the sound absorbing structure relative to the tire or the design information of the sound absorbing structure, and input design data including the changed placement information or design information into the terminal device 20.

[0079] <User Interface> The user interface of the analysis device 10 will be described with reference to Figs. 8 and 9. The user interface of the analysis device 10 may include an analysis condition screen (see Fig. 8) and an analysis result screen (see Fig. 9). The user interface of the analysis device 10 may be displayed on the display device 506 of the terminal device 20 or the display device 506 of the analysis device 10.

[0080] <<Analysis Condition Screen>> Fig. 8 is a diagram showing an example of the analysis condition screen. The analysis condition screen is a screen that displays the analysis conditions and accepts adjustments to the design information of the sound absorbing structure.

[0081] As shown in FIG. 8, the analysis condition screen 600 has a design adjustment section 610 , a calculation result display section 620 , a graph display section 630 , and a continue button 640 .

[0082] The design adjustment unit 610 adjustably displays the design information of the sound absorbing structure. In the example shown in Fig. 8 , the design adjustment unit 610 displays an incident angle 611, a resonant body outer radius 612, a resonant body length 613, a resonant body surface thickness 614, a buried neck length 615, a buried neck inner radius 616, and a buried neck thickness 617. The incident angle 611 is the angle of incidence of a sound wave on the opening of the buried Helmholtz resonator. The incident angle 611 may be adjusted depending on the orientation of the buried Helmholtz resonator when it is installed in a tire.

[0083] As an example, the design adjustment unit 610 displays the design information of the sound absorbing structure using slider bars that can be set to any value between a minimum and a maximum value. When the user operates one of the slider bars, the value of the design information corresponding to that slider bar is changed. When the value of the design information is changed, the condition presentation unit 150 accepts the adjustment of the design information of the sound absorbing structure.

[0084] The calculation result display unit 620 displays the calculation results based on the design information of the sound absorbing structure. In the example shown in Fig. 8, the calculation result display unit 620 displays a resonant body volume 621, a maximum sound absorption coefficient 622, and a frequency of the maximum sound absorption coefficient 623. When the design information of the sound absorbing structure is adjusted by the design adjustment unit 610, the calculation result display unit 620 is updated to display the calculation results recalculated based on the adjusted design conditions.

[0085] The graph display unit 630 displays the sound absorption coefficient curve of the sound absorbing structure and the resonant frequency of the space inside the tire. In the example shown in Fig. 8 , the graph display unit 630 displays a sound absorption coefficient curve 631 showing the relationship between frequency and sound absorption coefficient and a resonant frequency 632 of the space inside the tire, with the horizontal axis representing frequency and the vertical axis representing sound absorption coefficient. The peak value of the sound absorption coefficient curve 631 displayed on the graph display unit 630 corresponds to the maximum sound absorption coefficient 622. Furthermore, the frequency showing the peak of the sound absorption coefficient curve 631 corresponds to the frequency 623 of the maximum sound absorption coefficient.

[0086] The sound absorbing structure to be installed in the tire interior space should exhibit maximum sound absorbing characteristics at the resonant frequency of the tire interior space. The user may adjust the design information of the sound absorbing structure so that the peak of the sound absorption coefficient curve 631 displayed on the graph display unit 630 coincides with the resonant frequency 632.

[0087] The continue button 640 is a button for instructing analysis of sound pressure distribution based on the analysis conditions displayed on the analysis condition screen 600. When the user presses the continue button 640, the condition presenting unit 150 accepts an instruction for analysis based on the design conditions.

[0088] <<Analysis Result Screen>> Fig. 9 is a diagram showing an example of the analysis result screen. The analysis result screen is a screen that accepts input of design data and displays the analysis results.

[0089] As shown in FIG. 9 , the analysis result screen 700 has a frequency input section 710, a tire design input section 720, a sound absorbing structure design input section 730, a layout information input section 740, a sound pressure distribution display section 750, and a maximum value display section 760.

[0090] The frequency input unit 710 accepts input of a resonance frequency. In the example shown in Fig. 9, the frequency input unit 710 displays a resonance frequency 711. A desired resonance frequency may be input as the resonance frequency 711 by the user, or a resonance frequency calculated based on tire design information may be automatically input.

[0091] The tire design input unit 720 receives input of tire design information. In the example shown in Fig. 9, the tire design input unit 720 displays a tire width 721, a tire outer diameter 722, a tire inner diameter 723, and a tire thickness 724.

[0092] The sound absorbing structure design input unit 730 accepts input of design information for a sound absorbing structure. In the example shown in Fig. 9, the sound absorbing structure design input unit 730 displays a resonant body outer radius 731, a resonant body inner length 732, a resonant body surface thickness 733, a buried neck length 734, a buried neck inner radius 735, and a buried neck thickness 736.

[0093] The placement information input unit 740 accepts input of placement information for the sound absorbing structure. In the example shown in Fig. 9, the placement information input unit 740 displays placement angles 741 to 744 for the sound absorbing structure. The number of input fields for the placement angles may be increased or decreased arbitrarily. The increase or decrease of the number of input fields may be performed by a user operation.

[0094] The sound pressure distribution display unit 750 visualizes the sound pressure distribution in the space inside the tire. In the example shown in Fig. 9, the sound pressure distribution in the space inside the tire is shown by displaying shading according to the sound pressure level value on a perspective view of the tire. The sound pressure distribution display unit 750 may switchably display the sound pressure distribution for each rotation angle. The sound pressure distribution display unit 750 may continuously display the sound pressure distribution for each rotation angle, thereby displaying the change in the sound pressure distribution as an animation.

[0095] The maximum value display section 760 displays a graph showing the maximum sound pressure level for each rotation angle. In the example shown in Fig. 9, the maximum value display section 760 displays a curve showing the relationship between the rotation angle and the maximum sound pressure level, with the horizontal axis representing the rotation angle and the vertical axis representing the maximum sound pressure level. Note that the example shown in Fig. 9 shows the maximum sound pressure level when two sound absorbing structures are installed on a tire.

[0096] The sound pressure distribution display section 750 and maximum value display section 760 do not need to be displayed in the initial display of the analysis result screen 700. When the user inputs design data into the frequency input section 710, tire design input section 720, sound absorbing structure design input section 730, and layout information input section 740 on the analysis result screen 700, the analysis condition screen 600 is displayed. When the user presses the continue button 640 on the analysis condition screen 600, the analysis result screen 700 is displayed with the sound pressure distribution display section 750 and maximum value display section 760 displayed.

[0097] Effects of the embodiment The analysis device 10 in this embodiment calculates the sound absorption coefficient based on design information of the sound absorbing structure, generates a finite element model based on design information of the tire, sets a sound absorbing boundary having a sound absorption coefficient in the finite element model based on arrangement information of the sound absorbing structure with respect to the tire, and analyzes the sound pressure distribution in the internal space of the tire based on the finite element model in which the sound absorbing boundary has been set.

[0098] According to one aspect, the present embodiment makes it possible to analyze the sound pressure distribution in the space inside a tire in which a sound absorbing structure is installed with a small amount of calculation. According to another aspect, the present embodiment makes it possible to efficiently design and arrange the sound absorbing structure optimally.

[0099] The analysis device 10 may analyze the sound pressure distribution in the tire internal space by a coupled analysis of vibration analysis and acoustic analysis. According to this embodiment, the sound pressure distribution in the tire internal space can be analyzed with a small amount of calculation based on a finite element model in which sound-absorbing boundaries are set.

[0100] The analysis device 10 may analyze a plurality of sound pressure distributions with different positional relationships between the vibration position and the sound absorbing boundary. The analysis device 10 may also analyze the sound pressure distribution for each rotation angle when the position of the sound absorbing boundary is rotated by a predetermined rotation angle while the vibration position is fixed. According to this embodiment, it is possible to analyze the sound pressure distribution taking into account the usage state of the tire.

[0101] The analysis device 10 may output an analysis result including a sound pressure distribution for each rotation angle and a maximum value of the sound pressure level for each sound pressure distribution. According to this embodiment, the analysis result can be displayed in a manner that is easy for the user to understand.

[0102] The analysis device 10 may output a sound absorption coefficient curve based on design information of the sound absorbing structure and a resonance frequency based on design information of the tire. The analysis device 10 may also accept adjustments to the design information of the sound absorbing structure. According to this embodiment, since the analysis conditions can be confirmed before the analysis, the sound pressure distribution in the space inside the tire can be analyzed under appropriate analysis conditions.

[0103] The sound absorbing structure may be a Helmholtz resonator with an embedded neck. The sound absorbing structure may be installed on the inner surface of the tire tread. According to this embodiment, when an embedded Helmholtz resonator is installed on the inner surface of the tire tread, the sound pressure distribution in the space inside the tire can be efficiently analyzed.

[0104] [Supplementary Note] Each function of the above-described embodiments can be realized by one or more processing circuits. Here, the term "processing circuit" in this specification includes a processor programmed to execute each function by software, such as a CPU (Central Processing Unit) or GPU (Graphics Processing Unit) implemented by an electronic circuit, as well as devices such as an ASIC (Application Specific Integrated Circuit), DSP (Digital Signal Processor), FPGA (Field Programmable Gate Array), and conventional circuit modules designed to execute each of the above-described functions.

[0105] Although the embodiments of the present disclosure have been described in detail above, the embodiments disclosed herein are illustrative in all respects and are not limiting. The embodiments can be modified and improved in various ways without departing from the scope and spirit of the appended claims. The matters described in the above embodiments can be configured in other ways as long as they are not inconsistent, and can be combined as long as they are not inconsistent.

[0106] 10: Analysis device 20: Terminal device 110: Design acquisition unit 120: Modeling unit 130: Frequency calculation unit 140: Sound absorption coefficient calculation unit 150: Condition presentation unit 160: Sound absorption coefficient setting unit 170: Sound pressure analysis unit 180: Result output unit 1000: Analysis system

Claims

1. An analysis device comprising: a sound absorption coefficient calculation unit configured to calculate a sound absorption coefficient based on design information of a sound absorbing structure; a modeling unit configured to generate a finite element model based on design information of a tire; a sound absorption coefficient setting unit configured to set a sound absorbing boundary having the sound absorption coefficient in the finite element model based on arrangement information of the sound absorbing structure with respect to the tire; and a sound pressure analysis unit configured to analyze the sound pressure distribution in the internal space of the tire based on the finite element model in which the sound absorbing boundary has been set.

2. An analysis device according to claim 1, wherein the sound pressure analysis unit is configured to analyze the sound pressure distribution in the internal space of the tire by a coupled analysis of vibration analysis and acoustic analysis.

3. An analysis device according to claim 2, wherein the sound pressure analysis unit is configured to analyze a plurality of sound pressure distributions having different positional relationships between the vibration position and the sound absorbing boundary.

4. An analysis device according to claim 3, wherein the sound pressure analysis unit is configured to analyze the sound pressure distribution for each rotation angle when the position of the sound absorbing boundary is rotated by a predetermined rotation angle while the vibration position is fixed.

5. An analysis device according to claim 4, further comprising a result output unit configured to output an analysis result including the sound pressure distribution for each rotation angle and the maximum value of the sound pressure level for each sound pressure distribution.

6. An analysis device according to any one of claims 1 to 5, further comprising: a design acquisition unit configured to acquire design information for the sound absorbing structure and design information for the tire; and a condition presentation unit configured to output a sound absorption coefficient curve based on the design information for the sound absorbing structure and a resonance frequency based on the design information for the tire.

7. An analysis device according to claim 6, wherein the condition presentation unit is configured to accept adjustments to design information for the sound absorbing structure.

8. An analysis device according to any one of claims 1 to 7, wherein the sound absorbing structure is a Helmholtz resonator with an embedded neck, and is disposed on the inner surface of the tread portion of the tire.

9. An analysis method in which a computer executes the following steps: calculating a sound absorption coefficient based on design information of a sound absorbing structure; generating a finite element model based on design information of a tire; setting a sound absorbing boundary having the sound absorption coefficient in the finite element model based on arrangement information of the sound absorbing structure relative to the tire; and analyzing the sound pressure distribution in the internal space of the tire based on the finite element model in which the sound absorbing boundary has been set.

10. A program for causing a computer to execute the following steps: calculating a sound absorption coefficient based on design information of a sound absorbing structure; generating a finite element model based on design information of a tire; setting a sound absorbing boundary having the sound absorption coefficient in the finite element model based on arrangement information of the sound absorbing structure relative to the tire; and analyzing the sound pressure distribution in the internal space of the tire based on the finite element model in which the sound absorbing boundary has been set.

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