JP2020038159A - Vibration characteristic evaluation method and vibration characteristic evaluation device - Google Patents

Abstract

To provide a vibration characteristic evaluation method and a vibration characteristic evaluation device capable of appropriately processing an influence of input.SOLUTION: In a vibration characteristic evaluation method for vibrating a tire T when the tire T climbs over a projection 10 provided on a road surface, and detecting vibration of the tire T, vibration of a suspension system part S to which the tire T is fitted, and vibration in one portion of a vehicle to which the tire T is fitted, recording is performed so as to synchronize input that the projection 10 received from the tire T in vibration with output as vibration of the tire T, vibration of the suspension system part S to which the tire T is fitted, or vibration in one portion of a vehicle to which the tire T is fitted, and a frequency response function is computed as a ratio of an output Fourier spectrum to an input Fourier spectrum.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vibration characteristic evaluation method and a vibration characteristic evaluation device.

  Conventionally, a tire is brought into contact with a drum, the drum is rotated to rotate the tire, and the rotating tire is vibrated to detect the vibration of an axle on which the tire is mounted and evaluate the vibration characteristics. Had been In order to vibrate the tire, projections are provided on the surface of the drum as described in Patent Document 1. The tire was vibrated by getting over this protrusion.

  By the way, it is known that the magnitude of the excitation force affects the vibration detected by an axle or the like. Therefore, only by detecting the vibration of the axle, the vibration characteristics affected by the magnitude of the excitation force are evaluated, and the intended vibration characteristics cannot be accurately evaluated.

  On the other hand, as described in Patent Document 2, a method of detecting a force acting on a supporting portion of a rotating shaft of a drum, or as described in Patent Document 3, input to a tire using a hammer and A detection method has been proposed. However, none of the methods detect the magnitude of the vibration force caused by the protrusion on the drum surface.

  Also, as described in Non-Patent Document 3, a method has been proposed in which a sensor is attached to a protrusion on the surface of a drum and a road surface input is detected by the sensor. However, in this method, since the drum is rotating, the information of the road surface input detected on the drum side cannot be taken into the analyzer through the wiring, and the influence of the road surface input is appropriately processed to evaluate the vibration characteristics. Was an obstacle.

JP-A-2004-85297 JP-A-06-129954 JP 2006-119091 A

Mahara Matsubara et al., "Axle Response Analysis Using Road Surface Input When Rolling Tires", Preprints of the Society of Automotive Engineers of Japan Academic Lecture No. 103-08, 20085871

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vibration characteristic evaluation method and a vibration characteristic evaluation device in which the influence of an input is appropriately reflected.

  In the vibration characteristic evaluation method of the embodiment, the tire is vibrated by the tire passing over a protrusion provided on a road surface, and the vibration of the tire, the vibration of a suspension system portion on which the tire is mounted, or the mounting of the tire is performed. In the vibration characteristic evaluation method in which the vibration in a part of the vehicle is detected, the input by the force received by the projection from the tire at the time of the vibration, the vibration of the tire, the suspension system part on which the tire is mounted The recording is performed so that the output of the vibration, or the vibration of a part of the vehicle equipped with the tire, is synchronized, and a frequency response function is calculated as a ratio of the Fourier spectrum of the output to the Fourier spectrum of the input. It is characterized by that.

  Further, the vibration characteristic evaluation device of the embodiment includes a protrusion provided on a road surface, a vibration of the tire caused by the tire getting over the protrusion, a vibration of a suspension system portion on which the tire is mounted, or a mounting of the tire. An output sensor for detecting a vibration in a part of the vehicle, wherein an input sensor for detecting a force received by the projection from the tire is provided, and the input detected by the input sensor and the output sensor are provided. An analyzer is provided for recording the output so as to be synchronized with the detected output.

  According to the above-described method and apparatus for evaluating vibration characteristics, the input and the output are recorded in synchronization with each other, so that the influence of the input is appropriately reflected in the evaluation of the vibration characteristics performed after the recording.

FIG. 2 is a front view of the vibration characteristic evaluation device. FIG. 3 is a perspective view of an input sensor to which a protrusion is attached. Sectional drawing of the drum at the position of the input sensor. The figure which shows the slip ring of the example 2 of a change.

  An embodiment will be described with reference to the drawings. It should be noted that the embodiments described below are merely examples, and those that are appropriately changed without departing from the spirit of the present invention are included in the scope of the present invention.

1. Vibration Characteristics Evaluation Apparatus As shown in FIG. 1, the vibration characteristics evaluation apparatus of the present embodiment vibrates a cylindrical drum D for rotating a pneumatic tire (hereinafter, “tire”) T and a rotating tire T. A projection 10 provided on the surface of the drum D, an input sensor 11 for detecting the force received by the projection T from the tire T, an output sensor 20 for detecting the vibration (ie, output) of the axle S, and an input sensor 11 And an analyzer 30 that records information detected by the output sensor 20 and information detected by the output sensor 20 to obtain a frequency response function.

  For example, a force sensor is used as the input sensor 11. As shown in FIG. 2, a protrusion 10 is attached to a detection unit of the input sensor 11. On the other hand, as shown in FIG. 3, the outer peripheral surface of the drum D, that is, the rotating road surface is constituted by the surface plate 12. Holes 12 a are formed in the surface plate 12. The input sensor 11 is arranged on the back side (inner diameter side) of the surface plate 12 of the drum D. The projection 10 attached to the input sensor 11 projects from the hole 12a to the front side (outer diameter side) of the drum D. In the present embodiment, it is assumed that one input sensor 11 and one protrusion 10 are provided on the drum D. The protrusion 10 may be sufficiently small with respect to the contact surface of the tire T.

  As shown in FIG. 1, the tread portion of the tire T is pressed against the outer peripheral surface of the drum D (that is, the front surface of the surface plate 12). When the drum D rotates in this state, the tire T rotates in the opposite direction to the drum D. During this rotation, the tire T rides over the protrusions 10, whereby the tire T is vibrated. At this time, the input sensor 11 detects the force received by the protrusion 10 from the tire T (strictly, a change in the magnitude of the force (unit: N) received over time). As described above, the input sensor 11 detects a force (reaction force) received by the protrusion 10 from the tire T, and this reaction force is treated as an input to the tire T.

  A wireless transmitter 14 is attached to the drum D or a portion that rotates with the drum D (for example, a rotation axis A of the drum D as shown in FIG. 1). The input sensor 11 is connected to the first wireless transmitter 14 by a wiring (not shown). Input information detected by the input sensor 11 is sent to the wireless transmitter 14 and wirelessly transferred from the wireless transmitter 14 to the analyzer 30.

  The tire T to be evaluated is mounted on the wheel H. The tire T and the wheel H are rotatable about an axle S as a rotation axis. Note that the wheel H and the axle S are part of a suspension system. The axle S is supported by a non-rotating support portion 21. The axle S of the present embodiment does not have to be attached to the vehicle.

  An output sensor 20 for detecting vibration of the axle S is attached to the support 21. As the output sensor 20, for example, a force sensor, a displacement sensor, a speed sensor, or an acceleration sensor is used. The output sensor 20 of the present embodiment detects a specific one-way vibration. The output sensor 20 is connected to the analysis device 30, and information on an output detected by the output sensor 20 is sent to the analysis device 30.

  The analysis device 30 includes, for example, a wireless reception unit 31 that receives input information wirelessly transferred from the wireless transmitter 14, an output information acquisition unit 32 that acquires output information sent from the output sensor 20, A frequency response function calculation unit 33 for obtaining a frequency response function based on input and output information; an evaluation unit 34 for evaluating vibration characteristics based on the frequency response function; a storage unit 35 for storing acquired information and the like; A display unit 36 for displaying a response function and the like. For example, an FFT (Fast Fourier Transform) analyzer is used as such an analyzer 30. However, the wireless reception unit 31, the output information acquisition unit 32, the frequency response function calculation unit 33, the evaluation unit 34, the storage unit 35, and the display unit 36 do not necessarily need to be incorporated in one device. For example, a part including the wireless receiving unit 31 and the output information acquiring unit 32 may be incorporated in the analyzer, and the functions of the remaining part may be realized by a computer connected to the analyzer. The evaluation of the vibration characteristics based on the frequency response function may be performed by a person.

2. Vibration Characteristics Evaluation Method The tire vibration characteristics evaluation method of the present embodiment is performed by, for example, the above-described vibration characteristic evaluation device.

Specifically, the drum D starts to rotate, and accordingly, the tire T also starts to rotate. Then, when the tire T gets over the protrusion 10, the tire T is vibrated. When the tire T vibrates, the vibration is transmitted to the axle S. The force that the protrusion 10 receives from the tire T is detected by the input sensor 11. The vibration of the axle S is detected by the output sensor 20. What is detected by the output sensor 20 is, for example, force (unit: N), speed (unit: m / s), or acceleration (unit: m / s ² ). Here, based on the sampling theorem, the maximum frequency detected by the sensor is set to be at least twice the frequency of the vibration to be evaluated.

  The input information detected by the input sensor 11 is wirelessly transferred from the wireless transmitter 14 and received by the wireless receiving unit 31 of the analyzer 30. The output information detected by the output sensor 20 is obtained by the output information obtaining unit 32 of the analyzer 30. At this time, the input information and the output information are recorded in the analysis device 30 (more specifically, for example, the storage unit 35) in synchronization. Here, “recorded synchronously” means that the recording is performed in time. However, due to the time required for wireless transmission, etc., a slight interval (for example, within 1/10 of the reciprocal of the upper limit of the frequency of the vibration to be evaluated) may occur between the recording of the input information and the recording of the output information. There may be a time error. Even when there is such a time error, it can be said that “recorded in synchronization”. Further, in this embodiment, the synchronous recording of the input and output information is performed in parallel with the detection of vibration and the like by the input sensor 11 and the output sensor 20 while the drum D is rotating.

  For synchronous recording of the input and output information, for example, a mark may be provided on the outer peripheral surface of the drum D, and a detection sensor for detecting the mark may be provided. Then, a trigger signal may be issued when the detection sensor detects the mark on the drum D, and recording of input and output information may be started based on the trigger signal.

  Next, a frequency response function is calculated by the frequency response function calculation unit 33 based on the input and output information recorded in the analysis device 30. As represented by the following equation (I), the frequency response function H (f) is defined as the output Fourier spectrum B (f) divided by the input Fourier spectrum A (f).

  Therefore, the waveform of the frequency response function is obtained by dividing the output Fourier spectrum by the input Fourier spectrum for each frequency, and plotting the absolute value of the number (complex number) obtained thereby.

However, in a normal test, while there is little noise on the input side, various noises enter on the output side. Then, in order to reduce the influence of noise on the output side, the denominator and numerator on the right side of the above equation (I) are multiplied by the complex conjugate A ^* (f) of A (f), and the following equation (II) May be calculated based on the frequency response function H (f).

Conversely, to reduce the effect of noise on the input side, the denominator and numerator on the right side of the above equation (I) are multiplied by the complex conjugate B ^* (f) of B (f), and the following equation (III) Is calculated based on the frequency response function H (f).

Where A (f) A ^* (f) is the power spectrum of A (f), B (f) B ^* (f) is the power spectrum of B (f), B (f) A ^* (f) or A (f) B ^* (f) is the cross spectrum of A (f) and B (f).

  In a preferred embodiment, the steps from the vibration of the tire T to the calculation of the frequency response function are performed a plurality of times by rotating the drum D a plurality of times, and the final frequency response function is calculated from the average of the results of the plurality of times. . Of course, the process from the excitation of the tire T to the calculation of the frequency response function may be performed only once.

  Based on the frequency response function calculated in this manner, the evaluation unit 34 evaluates the vibration characteristics. Examples of the vibration characteristics include a natural frequency and a damping characteristic of the tire T. Specifically, since a plurality of peaks having a magnitude equal to or greater than a predetermined value appear in the waveform of the frequency response function, the frequencies of the peaks are obtained. The frequency of these peaks is the natural frequency of the tire T. Further, for example, an attenuation ratio is obtained as the attenuation characteristic. The attenuation ratio is obtained by, for example, a half width method or a curve fitting method.

  The waveform of the frequency response function and the evaluation result of the vibration characteristic thus obtained are displayed on the display unit 36. In addition, the information on the vibration, the frequency response function, the evaluation result of the vibration characteristic, and the like are stored in the storage unit 35.

  Although the method for evaluating the vibration characteristics of one tire T has been described above, a plurality of tires may be prepared, and the above-described test may be performed on each of the tires to calculate the frequency response function and evaluate the vibration characteristics. . Then, the superiority or inferiority of the tires may be evaluated based on a comparison of the vibration characteristics of a plurality of tires (for example, the magnitude and the damping ratio at the natural frequency). Here, the plurality of tires may be of different types. The type is classified based on the size, tread pattern, cross-sectional structure, and the like. Since the past test results are stored in the storage unit 35, the superiority of the tire is evaluated by comparing the test results with the results of the newly performed test.

  In addition, the above-described test may be performed by changing the condition given to the tire T, the frequency response function under each condition may be calculated, and the vibration characteristics under each condition may be evaluated. Then, the change in the vibration characteristic due to the change in the condition given to the tire T may be evaluated. Here, the conditions given to the tire T include the rotation speed of the tire T, the load applied to the tire T, the internal pressure of the tire T, the attitude angle of the tire T (that is, the angle of inclination with respect to the vertical direction), and the like. Further, as the change in the vibration characteristic, a change in the natural frequency of the tire T, a change in the damping characteristic, and the like are evaluated.

  Further, the position of the projection 10 may be moved in the width direction of the drum D, and the above-described test may be performed each time the movement is performed, so that a difference in vibration characteristics due to a difference in a position where the projection 10 contacts the tread portion may be evaluated. For example, in the case where a plurality of ribs are formed in the tread portion, the position of the protrusion 10 is moved in the width direction of the drum D, thereby changing the rib on which the protrusion 10 contacts. Differences in characteristics may be evaluated.

3. Effect In the present embodiment, since the force received by the projection 10 from the tire T is detected as the tire T gets over the projection 10 of the drum D, the input information can be used for evaluating the vibration characteristics. Further, since the output, which is the vibration of the axle S on which the tire T is mounted, is recorded so as to be synchronized with the input, there is almost no error in the time axis of the recorded input and output information, and the data is recorded after the recording. The influence of the input is appropriately reflected in the evaluation of the vibration characteristics.

  For example, calculating the frequency response function (ie, dividing the Fourier spectrum of the output for each frequency by the Fourier spectrum of the input) reveals the phase difference between the input and the output for each frequency. Here, it is conventionally known that a phase difference between an input and an output becomes a specific phase difference for each type of vibration mode. Therefore, from the phase difference between the input and output for each frequency, which is found by calculating the frequency response function, it is possible to specify which vibration mode the vibration at that frequency is. When specifying in this manner, if the input and output are recorded in synchronization with each other and there is almost no error in the time axis of the input and output information, the specification can be performed accurately.

  Further, in the present embodiment, since the Fourier spectrum of the input is calculated, the magnitude of the input for each frequency is obtained. Then, the output Fourier spectrum is divided by the input Fourier spectrum and the frequency response function is calculated as in the above equation (I). Therefore, the frequency response function is such that for each frequency, the magnitude of the output is the magnitude of the input. It will be broken. As a result, even if there is a variation in the magnitude of the input for each frequency, the influence of such variation is eliminated in the frequency response function. Therefore, if the vibration characteristic is evaluated based on the frequency response function, the evaluation is performed without the influence of the variation in the magnitude of the input for each frequency.

  In addition, the input becomes different when the tire is different, but in the present embodiment, the magnitude of the output is divided by the magnitude of the input for each frequency to obtain the frequency response function. A frequency response function from which the influence is eliminated is obtained. Therefore, if a plurality of tires are prepared, the frequency response function is calculated for each tire as described above, and the vibration characteristics are evaluated, the effect of the input difference based on the tire difference is eliminated, and the tire is removed. The difference in vibration characteristics based on the difference can be evaluated. Therefore, it is possible to accurately evaluate the superiority or inferiority of the vibration characteristics of the plural tires.

4. 4. Modifications Various modifications can be made to the embodiment described above without departing from the spirit of the invention. For example, any one or more of the following modifications can be made.

(1) Modification example 1
In the above embodiment, there is only one input and one output, but at least one of the input and the output may be plural. Also in this case, recording is performed so that the input and the output are synchronized, and a frequency response function is calculated from the Fourier spectrum of the input and the output.

  For example, as an input sensor, a sensor capable of independently detecting forces in three directions of a tire radial direction, a tire circumferential direction, and a tire width direction is used, and as an output sensor, an axle radial direction, an axle circumferential direction, and an axle longitudinal direction are used. Those that can independently detect vibrations in three directions are used. When a test is performed using such a sensor, the input in the three directions and the output in the three directions are recorded.

Then, as the Fourier spectrum of the input, the Fourier spectrum a ₁ input in the tire radial direction, the tire circumferential direction Fourier spectrum a ₂ input, are three Fourier spectrum a ₃ input in the tire width direction obtained. In addition, as the output Fourier spectrum, there are obtained a Fourier spectrum b ₁ of the output in the axle radial direction, a Fourier spectrum b ₂ of the output in the axle circumferential direction, and a Fourier spectrum b ₃ of the output in the axle longitudinal direction.

Then, a frequency response function H = [h _ij ] (i = 1, 2, 3; j = 1, 2, 3) is obtained by the following equation (IV).

Here, each component _hij of the frequency response function H which is a matrix can be obtained simultaneously by MIMO (Multi-Input / Multi-Output) analysis. Each component _hij describes the response of an input in each direction to an output in each direction. For example h ₁₂ shows the response to the output axle radial direction of the tire circumferential direction of the input.

  The input sensor may be capable of independently detecting forces in two directions or four or more directions. The output sensor may be capable of independently detecting vibration in two directions or four or more directions. Further, one of the input sensor and the output sensor may be able to detect only one direction, and the other may be independently detectable in a plurality of directions.

  Further, at least one of the input sensor and the output sensor may be provided in plural. For example, an input sensor may be provided at each of a plurality of locations in the tire width direction, and the input sensors may detect inputs of ribs having different tread portions. Further, output sensors may be provided at a plurality of locations of the vehicle, and sound and vibration at the plurality of locations may be detected.

  When at least one of the input sensor and the output sensor is provided in a plurality, the input sensor and the output sensor may be each capable of detecting only one direction, or may be independently detectable in multiple directions. It may be.

When at least one of the input and the output exists as described above, the number n of inputs and the number m of outputs are
(Number of inputs n) = (number of directions that one input sensor can detect) × (number of input sensors)
(Number of outputs m) = (Number of directions that one output sensor can detect) × (Number of output sensors)
Becomes

Thus, when there are n inputs and m outputs, the frequency response function H = [h _ij ] (i = 1,…, m; j = 1,…, n) is generalized to It is obtained by equation (V).

Here, a ₁ ,..., _An are the Fourier spectra of the input, respectively, and b ₁ ,..., B _m are the Fourier spectra of the output, respectively.

(2) Modification example 2
The information of the input detected by the input sensor 11 may be recorded in the analysis device 30 by means different from the above wireless transfer.

  For example, the input sensor 11 provided on the rotating drum D and the analysis device 30 may be electrically connected via a brush-type slip ring 40 as a rotary connection member. As shown in FIG. 4, the brush-type slip ring 40 includes a rotating body 41 fixed to the rotating axis A of the drum D and rotating with the rotating axis A, and a non-rotating body not fixed to the rotating axis A of the drum D. 42 (shaded portions in FIG. 4). Then, the conductive brush 44 extending from the non-rotating member 42 comes into contact with the electrode 43 of the rotating member 41, and the rotating member 41 side and the non-rotating member 42 side are electrically connected. The electrode 43 of the rotating body 41 and the input sensor 11 are connected, and the conductive brush 44 of the non-rotating body 42 and the analyzer 30 are connected.

  With this configuration, input information detected by the input sensor 11 is immediately sent to the analysis device 30. On the other hand, the output sensor 20 is also connected to the analysis device 30, and information on the output detected by the output sensor 20 is also sent to the analysis device 30 immediately. Therefore, the input and output information are recorded in the analyzer 30 in synchronization.

  Also, as a rotary connection member instead of the brush type slip ring 40, the rotating body side and the non-rotating body side are electrically connected through a liquid metal (for example, mercury) filled between the electrode of the rotating body and the electrode of the non-rotating body. A liquid metal rotary connector to be connected to the power supply may be used.

  In the method in which the brush type slip ring 40 or the liquid metal type rotary connector is used, the synchronous recording of the input and output information is performed while the rotation of the drum D is caused by vibrations of the input sensor 11 and the output sensor 20. It will be performed in parallel with the detection.

  Further, as another embodiment, a recording device (not shown) is provided on the rotation axis A of the drum D, and the input sensor 11 is connected to the recording device instead of the analysis device 30, and information of an input detected by the input sensor 11 is transmitted. The information may be recorded in this recording device. In this case, the input information is transferred from the recording device to the analyzer 30 after the rotation of the drum D is stopped, and the analyzer 30 synchronizes the input and output information. At this time, the above trigger signal may be used for synchronization. Even in such a case, it can be said that “recorded in synchronization”.

(3) Modification 3
The location where the output sensor 20 is provided is not limited to the support portion 21 of the axle S as described above. For example, the location where the output sensor 20 is provided may be a rotating part such as the wheel H or the axle S. In that case, it is preferable that the input information detected by the output sensor 20 be recorded in the analysis device 30 via a wireless or rotary connection member.

  Further, as an output sensor, a microphone that measures the sound pressure of the sound radiated from the tire T, an acoustic particle velocity sensor that measures the sound particle velocity of the sound radiated from the tire T, or the sound intensity of the sound radiated from the tire T A sound intensity sensor for measuring may be used. Note that the sound radiated from the tire T is sound radiated from the tire T. These output sensors are arranged apart from the tire T. It can be said that these output sensors indirectly detect the vibration of the tire T via the sound radiated from the tire T. When these output sensors are arranged inside the vehicle, it can be said that these output sensors detect vibration in a part of the vehicle on which the tire T is mounted. If the measurement results of these output sensors are used as outputs for vibration characteristic evaluation, it is possible to evaluate the transfer characteristics from input to radiated sound.

  Further, as the output sensor, a displacement sensor, a speed sensor, or an acceleration sensor that contacts the surface of the tire T and detects its vibration may be used. Further, as the output sensor, a laser displacement meter, a laser Doppler vibrometer, an ultrasonic sensor, an eddy current sensor, or an image sensor that detects the vibration of the surface of the tire T in a non-contact manner may be used.

(4) Modification 4
The test for evaluating the vibration characteristics may be performed using an actual vehicle (actual vehicle).

  For example, a test similar to that of the above-described embodiment may be provided on the rotating road surface of the chassis dynamo, and a test may be performed in which the actual vehicle is driven on the chassis dynamo to get over the projection with the tire T. By using the chassis dynamo, the vibration characteristics can be evaluated in a situation where disturbance such as wind is removed.

  Further, the same projections and output sensors as in the above embodiment may be provided on an actual pavement and flat road surface, and a test may be performed in which a real vehicle travels on the road surface to get over the projections with the tire T. By performing the test on an actual road surface, it is possible to evaluate the vibration characteristics under conditions close to the actual running conditions (conditions such as a flat road surface and wind resistance).

  In the evaluation of the vibration characteristics using the actual vehicle, it is possible to detect the vibration of the suspension system such as the axle S or the surface of the tire T as an output as described above, but it is possible to detect a part of the vehicle on which the tire T is mounted. Can be detected as an output. For example, the vibration of the floor or seat in the vehicle, the sound pressure at the position of the occupant's ear such as a turn, or the like may be detected as the output. This makes it possible to directly evaluate the influence of vibration on a driver such as a driver, and to evaluate vibration characteristics including the vehicle body.

  A: rotating shaft, D: drum, H: wheel, S: axle, T: tire, 10: protrusion, 11: input sensor, 12: surface plate, 12a: hole, 14: wireless transmitter, 20: output sensor, DESCRIPTION OF SYMBOLS 21 ... Support part, 30 ... Analysis apparatus, 31 ... Wireless receiving part, 32 ... Output information acquisition part, 33 ... Frequency response function calculation part, 34 ... Evaluation part, 35 ... Storage part, 36 ... Display part, 40 ... Slip ring 41, rotating body, 42, non-rotating body, 43, electrode, 44, conductive brush

Claims (9)

The tire is vibrated by the tire getting over the protrusion provided on the road surface, and the vibration of the tire, the vibration of the suspension system portion on which the tire is mounted, or the vibration of a part of the vehicle on which the tire is mounted is reduced. In the vibration characteristic evaluation method to be detected,
Input by the force received by the projection from the tire at the time of the vibration, vibration of the tire, vibration of a suspension system portion on which the tire is mounted, or vibration on a part of a vehicle on which the tire is mounted. A vibration characteristic evaluation method, wherein recording is performed so that the output is synchronized with the output, and a frequency response function is calculated as a ratio of the Fourier spectrum of the output to the Fourier spectrum of the input.   The vibration characteristic evaluation method according to claim 1, wherein frequency response functions of a plurality of tires are calculated, and the superiority or inferiority of the tire is evaluated based on the result.   The vibration characteristic evaluation method according to claim 1, wherein at least one of the input and the output includes a plurality.   4. The vibration characteristic evaluation method according to claim 3, wherein forces in one of the plurality of directions in the plurality of directions are inputs, and vibrations in a plurality of directions in one location are outputs. A protrusion provided on a road surface and vibration of the tire caused by the tire getting over the protrusion, vibration of a suspension system portion on which the tire is mounted, or vibration in a part of a vehicle on which the tire is mounted is detected. In a vibration characteristic evaluation device having an output sensor,
An input sensor for detecting a force applied to the projection from the tire is provided, and an analyzer is provided for recording the input detected by the input sensor and the output detected by the output sensor in synchronization. A vibration characteristic evaluation device.   The vibration characteristic evaluation device according to claim 5, further comprising a frequency response function calculator that calculates a frequency response function as a ratio of the Fourier spectrum of the output to the Fourier spectrum of the input. The input sensor is provided on a rotating road surface,
The vibration characteristic evaluation device according to claim 5, further comprising a wireless transmitter or a rotary connection member that sends information of an input detected by the input sensor to the analysis device.   The vibration characteristic evaluation device according to any one of claims 5 to 7, wherein the input sensor is capable of detecting forces in a plurality of directions. The vibration characteristic evaluation device according to claim 5, wherein a plurality of the input sensors are provided on the road surface.

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