Method and device for testing vibration characteristics of automobile body

Abstract

A method for testing vibration characteristics of an automobile body, which is a method for determining vibration characteristics of the automobile body (100) by inputting vibration to the automobile body (100), comprises: a vibration excitation step (S1) for setting a plurality of vibration input parts (111) on the automobile body (100) supported by an air cushion (211), vibration is inputted to each of the plurality of vibration input parts (111) so as to excite the vehicle body (100); and a vibration measurement step (S3) for measuring data relating to vibration characteristics of the vehicle body (100) that has been excited, in the excitation step (S1), the input wave of the vibration input to a part of the vibration input site (111) of the vehicle body (100) is delayed than the input wave of the vibration input to the other vibration input site (111).

Description

Technical Field

[0001] The present invention relates to a vibration characteristic test method and apparatus for an automotive body for obtaining vibration characteristics related to vibration and noise generated in the automotive body. Background Art

[0002] The measurement of vibrations generated in the automobile body and felt by passengers when the automobile is running, and internal vehicle noise, is mostly carried out in the state of a completed vehicle, such as a road test of a completed vehicle, a bench test in which a completed car is placed on a shake table and vibrations are input to the wheels (for example, see Patent Document 1). In contrast, in the stage of designing the automobile body structure, there are few tests to evaluate the influence of materials used in the automobile body structure and automobile parts on vibration characteristics such as vibrations and noises generated in the automobile body.

[0003] In addition, the following test is conducted: vibration is input to one point of the automotive body floor in a state where the automobile body is fixed, and the vibration characteristics generated in various parts of the automobile body are obtained. However, in this test, if the local elastic deformation near the part of the automobile body where the vibration is input (hereinafter referred to as the "vibration input part") is taken into account, a large excitation force cannot be applied to the vibration input part. Therefore, there is a tendency that the vibration level excited in the part away from the vibration input part becomes smaller due to insufficient excitation force.

[0004] Furthermore, if the vibration level of the automobile body obtained when the excitation force is insufficient is used to perform vibration mode analysis of the entire automobile body, there is a possibility that the deformation state of the automobile body estimated by the vibration mode analysis will be biased. In order to eliminate such a bias, repeated tests are performed while changing the vibration input location in the automobile body at multiple locations, and the vibration data obtained for multiple vibration input locations are averaged to obtain the true natural vibration mode.

[0005] However, the vibration input from the road to the car body when the finished car is actually running is the vibration input to the part where the tires, suspension and the like are connected to the car body. In contrast, the vibration mode analysis obtained by inputting vibration to a certain point of the car body and exciting it is only a means of determining the natural vibration mode of the car body structure, especially the lower order, so it is difficult to say that it reproduces the vibration phenomenon generated when the finished car is running.

[0006] In addition, the road noise and booming noise generated when the finished vehicle is running are noises in the audible range (20 Hz to 2.0 kHz) in the vehicle cabin, which are generated by the vibrations input from the tires, the vibrations of the body frame parts, and the vibrations of the panel parts transmitted through the body frame parts. In order to evaluate the noise level of 20 Hz to 2.0 kHz in the vehicle cabin, it is important to evaluate the vibration characteristics of the vehicle body structure under vibration conditions close to those when the finished vehicle is running.

[0007] Patent document 2 discloses a steering stability evaluation technology that simulates vibrations input from the road surface during driving by using a bench test of a vehicle in a finished vehicle state. This technology is a test method used to simulate the rotational movement, rolling (around the front and rear axes), pitching (around the left and right axes), and yawing (around the upper and lower axes) of the vehicle body suspended on the four-wheel suspension under periodic steering (steering operations) such as continuous lane changes and slalom running, and mainly evaluates the performance of tires and suspensions. In this test method, tires are placed on multiple exciters that excite the vehicle in a finished vehicle state, and the excitation waveform (sine wave) input to the left, right, front and rear tires is staggered by half a cycle each time to evaluate the steering stability performance by individually controlling the excitation controller of the multiple exciters. Steering during driving is performed slowly from the perspective of safety and ride comfort, but steering during zigzag driving, emergency avoidance lane change, etc. is the fastest operation, which is equivalent to about 1.0 Hz when expressed in a periodic manner. Therefore, in the handling stability evaluation technology of Patent Document 2, it is not envisaged to evaluate the vibration characteristics of the body structure in the frequency domain (20 Hz to 2.0 kHz) of the noise in the cabin. In addition, in the excitation method of Patent Document 2, the body structure (body-in-white) is excited via the tires and suspension, so when evaluating the audible range frequency band above 20 Hz, the vibration damping is large, and the vibration response of the observed object becomes small, which is not suitable as an evaluation method.

[0008] Therefore, in order to input vibration into the automobile body and evaluate the differences in vibration and noise caused by the materials used in the vehicle body structure and body parts, it is appropriate to conduct a test to simultaneously input vibration into multiple vibration input locations in the automobile body and reproduce the vibration phenomenon when the completed vehicle is running.

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: Japanese Patent Application Publication No. 2000-88697

[0012] Patent Document 2: Japanese Patent Application Publication No. 2011-247262 Summary of the invention

[0013] Problems to be solved by the invention

[0014] Generally, the evaluation of automobile body vibration and cabin noise is mainly based on sensory evaluation (perceptual evaluation) or acoustic measurement based on driving tests of completed vehicles. There are few examples of evaluating vibration characteristics in the body structure alone, the so-called white body. Therefore, in order to know the vibration characteristics such as vibration generated in the automobile body and cabin noise at the stage of designing the body structure, it is necessary to make predictions through CAE (Computer Aided Engineering) analysis based on the preparation of an analysis model close to the completed vehicle. In addition, through such CAE analysis, it is possible to evaluate how the vibration characteristics of the automobile body change due to changes in the body structure and the materials used for body parts.

[0015] In order to ensure the predicted value of the vibration characteristics of the automobile body based on CAE analysis and ensure its accuracy, it is necessary to obtain measurement data related to the vibration characteristics of the completed vehicle through driving tests or bench tests. However, obtaining such measurement data requires a lot of time and cost. In contrast, if the vibration characteristics test (vibration characteristics testing) based on the body-in-white of the vehicle structure can be carried out, the time required for the preparation of the analytical model for CAE analysis and CAE analysis can be greatly reduced, and the vibration characteristics of the automobile body can be easily obtained in the design stage of the vehicle body structure.

[0016] In the test for obtaining the vibration characteristics of such a vehicle body, how to reproduce the vibration state generated in the vehicle body when the vehicle is running becomes the key. However, in order to conduct such a vibration characteristic test using the vehicle body, there are the following two problems.

[0017] The first challenge is to reproduce the constraint conditions of the automobile body based on the surrounding parts such as the chassis and suspension. This challenge is solved by supporting the automobile body with air cushions (air springs).

[0018] In addition, the second topic is the excitation method for exciting vibration and noise to the automobile body. Regarding this topic, there is a method to reproduce the input wave (wave form, frequency, etc.) of the vibration input to the automobile body based on the measurement data of the vibration characteristics of the actual vehicle driving test. However, this method is limited to the test of exciting the automobile body by inputting the vibration of the waveform obtained under several specified road surface conditions. Therefore, there is no test to parametrically change the countless different road conditions, vibration input parts and vehicle running conditions (driving speed, etc.) to excite the automobile body. Therefore, in the test of exciting the automobile body to obtain the vibration characteristics of the automobile body, it is expected to be able to appropriately change the vibration input part of the automobile body, the input wave of the input vibration and reproduce the various road conditions and vehicle running conditions when the actual car is driving.

[0019] The present invention is made to solve the above-mentioned problems, and its purpose is to provide a vehicle body vibration characteristics test method and device that can appropriately reproduce the road surface state and vehicle driving conditions when the actual vehicle is running to obtain the vibration characteristics of the vehicle body.

[0020] Means for solving problems

[0021] The vibration characteristic test method of a car body of the present invention is a method for inputting vibration into a car body to obtain the vibration characteristic of the car body, comprising: an excitation process, setting a plurality of vibration input parts on the car body supported by an air cushion, inputting vibration to each of the plurality of vibration input parts to excite the car body; and a vibration measurement process, measuring data related to the vibration characteristic of the car body excited in the excitation process, wherein in the excitation process, an input wave of vibration input to a part of the vibration input parts in the car body is delayed compared to an input wave of vibration input to other vibration input parts.

[0022] Alternatively, in the vibration excitation step, the vibration input portion is set on the right side and the left side at the rear of the automobile body, a plurality of reference signals of a sine wave or a random wave are generated as references of input waves of vibrations input to the respective vibration input portions, a delay signal is generated which delays a portion of the plurality of reference signals generated, vibrations with the reference signal as input waves are input to the vibration input portion on either the left side or the right side at the rear of the automobile body, and vibrations with the delay signal as input waves are input to the vibration input portion on the other of the left side or the right side at the rear of the automobile body.

[0023] Alternatively, in the vibration excitation process, the vibration input parts are set at the front and rear of the automobile body, a plurality of reference signals of sinusoidal waves or random waves are generated as references of the input waves of the vibrations input to the respective vibration input parts, a delay signal is generated which delays a part of the plurality of reference signals generated, the vibration with the reference signal as the input wave is input to the vibration input part at the front of the automobile body, and the vibration with the delayed signal as the input wave is input to the vibration input part at the rear of the automobile body.

[0024] Alternatively, in the vibration measuring step, as data related to the vibration characteristics, an accelerometer may be provided on the vehicle body to measure vibration acceleration generated in the vehicle body, and / or a microphone may be provided inside the vehicle body to measure sound pressure of noise generated from the vehicle body.

[0025] The vibration characteristic test device of the automobile body of the present invention inputs vibration to the automobile body to obtain the vibration characteristic of the automobile body, and comprises: an excitation device (excitation device) for exciting the automobile body by inputting vibration to each of a plurality of vibration input locations set in the automobile body supported by an air cushion; and a vibration measuring device for measuring data related to the vibration characteristic of the automobile body excited by the excitation device, wherein the excitation device comprises: a plurality of exciters (exciters / shales) for exciting by inputting vibration of a predetermined input wave to a plurality of the vibration input locations in the automobile body; a signal generating device for generating a plurality of reference signals as references of the input waves of the vibrations input to the respective vibration input locations; a delay processing device (delay processing device) for delaying a portion of the generated reference signals to generate delay signals; and a plurality of exciter control devices for driving and controlling the plurality of exciters respectively by means of the generated reference signals or delay signals. control), the vibration measuring device comprises: an accelerometer arranged on the automobile body and measuring the vibration acceleration generated in the automobile body, and / or a microphone arranged inside the automobile body and measuring data related to the noise generated from the automobile body; an exciting force / input accelerometer, measuring the exciting force and input acceleration (input acceleration) that excite the automobile body by the vibration input to the automobile body; and a data recorder, obtaining the vibration acceleration measured by the accelerometer and / or the sound pressure of the noise measured by the microphone, and the exciting force and input acceleration measured by the exciting force / input accelerometer.

[0026] Effects of the Invention

[0027] According to the present invention, it is possible to reproduce the vibration state excited in the automobile body under the road surface state and the driving conditions of the vehicle when the actual vehicle is running, and to obtain the vibration characteristics such as vibration and noise generated in the automobile body. As a result, in the design stage of the automobile body, the changes in the vibration characteristics of the automobile body caused by the changes in the body structure and materials can be obtained. In addition, the vibration input conditions that simulate the road surface state and driving conditions (driving speed, etc.) when the actual vehicle is running can be changed parameter-wise, so the analytical modeling for CAE analysis also becomes easy. Moreover, since it is easy to specify the input wave of the vibration input to each of the multiple vibration input parts in the automobile body and its delay time, the standardization and reproducibility of the vibration input conditions related to the vibration input to the automobile body in the vibration characteristic test are also good.

[0028] In addition, the present invention can reduce the output of the exciter and the exciting force by directly exciting the body frame at the body suspension part and the suspension joint peripheral part, and can perform efficient vibration testing. In particular, although the measured signal response is small, it is easy to produce differences in sensory evaluation, and the noise level of 20Hz to 2.0kHz, which is the audible range, and the vibration characteristics of the body frame can be accurately evaluated. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a flowchart illustrating the process flow of the automobile body vibration characteristic test method according to the embodiment of the present invention.

[0030] Figure 2 It is a diagram for explaining a first embodiment of a plurality of vibration input locations for inputting vibrations into a vehicle body in the vehicle body vibration characteristics test method and apparatus according to the embodiment of the present invention.

[0031] Figure 3 It is a diagram for explaining a second aspect of a plurality of vibration input locations in a vehicle body in the vehicle body vibration characteristic test method and apparatus according to the embodiment of the present invention.

[0032] Figure 4 It is a block diagram for explaining the structure of the vibration characteristics test device of the automobile body according to the embodiment of the present invention.

[0033] Figure 5 This is a diagram showing an example of the installation state of a vibration exciter for inputting vibration to a vehicle body in the vehicle body vibration characteristics test apparatus according to the embodiment of the present invention.

[0034] Figure 6 The figures show specific examples of the method of inputting vibration into a vehicle body and exciting it in the vehicle body vibration characteristics test device according to the embodiment of the present invention ((a) first method, (b) second method).

[0035] Figure 7 This is a block diagram (part 1) for explaining another configuration of the vehicle body vibration characteristics test device according to the embodiment of the present invention.

[0036] Figure 8 This is a block diagram (part 2) for explaining another configuration of the vehicle body vibration characteristics test device according to the embodiment of the present invention.

[0037] Fig. 9 The graphs are graphs showing frequency response spectra of vibrations generated in the vehicle body when random wave vibrations are input to the vibration input locations at the front and rear of the vehicle body in Example 1 ((a) delay time 125 ms, (b) delay time 90 ms).

[0038] Fig.10 The figures show the parts where the vibration acceleration generated in the automobile body is measured by inputting sinusoidal vibration to the vibration input parts on the right and left sides of the rear of the automobile body in Example 1 ((a) side view, (b) top view).

[0039] Fig.11 The graph is a graph showing the peak amplitude ratio of vibration acceleration generated at each location when vibration is input to the right and left rear sides of the automobile body in Example 1 by applying delay processing with phase differences of 0°, 90°, and 180°.

[0040] Fig.12 The figures show the parts where the vibration acceleration generated in the automobile body is measured by inputting sinusoidal vibration to the vibration input parts at the front and rear of the automobile body in Example 2 ((a) side view, (b) top view).

[0041] Fig.13 It is a graph showing the frequency response spectrum of vibration generated in the automobile body when random wave vibration is input to the vibration input parts in the front and rear of the automobile body in Example 2 ((a) 20~100 Hz low frequency band, (b) 100~400 Hz medium frequency band). DETAILED DESCRIPTION

[0042] <Automobile body>

[0043] In the present invention, the automobile body to be tested for vibration characteristics is a so-called body frame (body in white) that does not include a chassis part, a suspension part, a driving system part, an interior part, etc. In the embodiment of the present invention described below, as an example, Figure 2 The vehicle body 100 shown is an object. The vehicle body 100 includes vehicle body frame members such as a front side member 101 , a rear side member 103 , a bumper reinforcement 105 , and a rear floor cross member 107 , and panel members such as a vehicle body floor 109 .

[0044] like Figure 2As shown, in the automobile body 100, the body floor 109 of the automobile body 100 is placed and supported on four air cushions 211 provided on the ground 201. Therefore, when vibration is input to the automobile body 100, the body floor 109 supported by the air cushions 211 is not restrained and the automobile body 100 is excited.

[0045] However, the location and method of supporting the automobile body 100 of the present invention are not limited thereto, and the location and method of supporting the automobile body 100 may be appropriately selected according to the vibration characteristics of the evaluation object.

[0046] Hereinafter, the automobile body vibration characteristic test method and apparatus (hereinafter respectively referred to as “vibration characteristic test method” and “vibration characteristic test apparatus”) of the present invention will be described with respect to the case where the automobile body 100 is the object of the vibration characteristic test.

[0047] <Vibration characteristics test method>

[0048] like Figure 2 As shown in FIG. 1 , the vibration characteristic test method of this embodiment inputs vibration to the automobile body 100 and obtains the vibration characteristic of the automobile body 100. Figure 1 As shown, the vibration characteristics test method of this embodiment includes a vibration excitation step S1 and a vibration measurement step S3.

[0049] 《Vibration Process》

[0050] like Figure 2 As shown, as an example, the vibration excitation step S1 sets a plurality of vibration input locations 111 (111a, 111b) on the automobile body 100 in which the vehicle body floor 109 is supported by the air cushion 211 provided on the ground 201. Then, the vibration excitation step S1 inputs vibration to each of the plurality of vibration input locations 111 set to vibrate the automobile body 100.

[0051] Furthermore, in the excitation step S1 , the vibration input wave input to some vibration input sites 111 (eg 111 b ) among the plurality of vibration input sites 111 is delayed compared to the vibration input wave input to the other vibration input sites 111 (eg 111 a ).

[0052] 《Vibration Measurement Process》

[0053] The vibration measuring step S3 is a step of measuring data related to the vibration characteristics of the automobile body 100 excited in the vibration exciting step S1 .

[0054] In the present embodiment, the vibration measuring step S3 is to install an accelerometer on the automobile body 100 to measure the vibration acceleration generated in the automobile body 100 as data related to the vibration characteristics of the automobile body 100 .

[0055] Next, in the vibration excitation step S1 of the vibration characteristics test method according to the present embodiment, a description will be given of a plurality of vibration input sites 111 set in the automobile body 100 and input waves of vibrations input to the respective vibration input sites.

[0056] The vibration generated in the automobile body 100 during the actual vehicle running tends to be emphasized when the vibration of the waveform excited by the periodic grooves of the road surface or the periodic sipe pattern of the tire surface is input, compared with the case where the vibration of the waveform is input independently to the four wheels. In addition, when there is a resonance point of the same frequency as the vibration input from the road surface in the automobile body 100, the vibration excited by the automobile body 100 and the noise in the vehicle interior may become larger.

[0057] Therefore, in order to simulate the vibration input to the automobile body 100 when the actual vehicle is running, in the vibration excitation step S1 , (a) a plurality of vibration input locations 111 and (b) the vibration input to each vibration input location 111 are set as follows.

[0058] (a) Setting of vibration input location

[0059] Regarding the plurality of vibration input locations 111 set on the automobile body 100, there are the aforementioned Figure 2 The first method and Figure 3 The second way illustrated.

[0060] like Figure 2 As shown in the figure, the first mode sets vibration input parts 111a and 111b on the right and left sides of the rear of the automobile body 100. This assumes the case of off-road running or rough-road running on a gravel road in a front engine front drive vehicle (FF vehicle) in which body parts of a drive system such as an engine and a transmission are arranged in front of the vehicle.

[0061] When driving on rough roads such as off-road or stone roads, the vibration input from the left and right tires can be regarded as a large phase deviation. In the case of an FF vehicle, since a heavy object is suspended in front of the vehicle (front side), the vibration (amplitude) of the front side of the vehicle is suppressed. In contrast, the rear (rear side) of the vehicle with less weight distribution is in a state of easy vibration, and there is a tendency for the amplitude (displacement) of the vibration to become larger than that of the front of the vehicle. Therefore, when driving on rough roads, the displacement of the front of the heavy vehicle is small, and the rear of the vehicle is relatively large. As a result, the contribution of the deformation mode that deforms in the torsional direction in the automobile body becomes larger. In the first method, in order to reproduce the vibration state of vibrating centered on the rear of the FF vehicle, in the excitation step S1, a vibration input part 111a and a vibration input part 111b are set on the right and left sides of the rear of the automobile body 100, respectively. Furthermore, the phase of the vibration input wave input to the left vibration input portion 111b is delayed compared to the phase of the vibration input wave input to the right vibration input portion 111a, and vibration is input to the vibration input portions 111a and 111b respectively to excite the automobile body 100.

[0062] like Figure 3 As shown, in the second embodiment, vibration input locations 111c and 111d are respectively set at the front and rear of the automobile body 100. This assumes that vibrations of the same waveform are input to the vehicle from the front and rear tires due to the unevenness of the road surface.

[0063] When the actual vehicle is running, the waveform of the vibration input to the front and rear of the vehicle is the same due to the unevenness of the road surface, but there is a slight time difference between the vibration input to the front and rear. Therefore, in the second method, in order to reproduce the vibration state of the same waveform of vibration input to the front and rear of the vehicle with the time difference, in the excitation step S1, the vibration input part 111c and the vibration input part 111d are respectively set at the front and rear of the automobile body 100. And, the phase of the vibration input wave input to the vibration input part 111d at the rear of the automobile body 100 is delayed compared with the phase of the vibration input wave input to the vibration input part 111c at the front, and the vibration is input to the vibration input parts 111c and 111d respectively to excite the automobile body 100.

[0064] (b) Excitation method

[0065] As a method for exciting by inputting vibration into each vibration input part 111 of the automobile body 100, it is possible to apply (bi) a method of exciting steady-state vibration by inputting sinusoidal vibration of a specified frequency for a certain period of time, and (b-ii) a method of exciting by inputting random wave vibration continuously for a certain period of time.

[0066] (bi) Excitation based on a sine wave vibration input of a specified frequency

[0067] Excitation based on sine wave vibration input is effective for tests that assume vibration input to the car body through periodic structures on the road surface such as drainage grooves when the actual vehicle is running, or tests that determine vibration characteristics related to a predetermined frequency of main vibration and noise generation confirmed during CAE analysis and actual vehicle running. In particular, excitation based on sine wave vibration input is useful in a frequency band of approximately 200 Hz or less where the natural frequency peak of the vibration generated by the car body is clear.

[0068] like Figure 3 As shown in the figure, a method of setting the vibration input part 111c and the vibration input part 111d at the front and rear of the automobile body 100 and inputting sinusoidal wave vibration to each vibration input part 111c and 111d is described.

[0069] First, as a reference of the vibration input wave input to each vibration input part 111c, 111d, a reference signal of a sine wave of a predetermined frequency is generated. And the vibration input wave input to the vibration input part 111c in the front of the automobile body 100 is used as the reference signal. On the other hand, the vibration input wave input to the vibration input part 111d in the rear of the automobile body 100 becomes a delayed signal obtained by delaying the reference signal.

[0070] When the reference signal is a sine wave, the delay signal can be generated by delaying the reference signal by assigning a phase difference of 0° to 180°. By setting the phase difference of the vibration input wave input to the vibration input parts 111c and 111d between 0° and 180° in front and rear of the automobile body 100, various vibration modes can be reproduced in the automobile body 100. Delaying the reference signal by assigning a phase difference to the sine wave is synonymous with delaying the reference signal by assigning a delay time equivalent to the phase difference. Therefore, a delay signal can also be generated by assigning a predetermined delay time to the reference signal and delaying it.

[0071] Then, if Figure 2As shown in the figure, a method of setting a vibration input part 111a and a vibration input part 111b on the right side and the left side of the rear of the automobile body 100, respectively, and inputting sinusoidal wave vibration to each vibration input part 111a, 111b is described.

[0072] First, as a reference of the vibration input wave input to each vibration input part 111a, 111b, a reference signal of a sine wave of a predetermined frequency is generated. And the vibration input wave input to the vibration input part 111a on the right side of the rear of the automobile body 100 is used as the reference signal. On the other hand, the vibration input wave input to the vibration input part 111b on the left side of the rear of the automobile body 100 becomes a delayed signal that delays the reference signal.

[0073] In the vibration excitation step S1 , in order to reproduce a complete torsional mode deformation in the automobile body 100 , the vibration input waves input to the vibration input parts 111 a and 111 b are sinusoidal waves, and the phase difference of the input waves is set to 180 degrees to invert the phases.

[0074] However, in the vibration input during the running of the actual vehicle, it is assumed that in addition to torsion, the vibration modes of vertical bending or horizontal bending compound are mostly excited. In order to reproduce such various vibration modes in the automobile body 100, the vibration input wave is set to a sine wave in the excitation step S1, and the phase difference of the vibration input wave input to the vibration input part 111a and the vibration input part 111b is set between 0° and 180°.

[0075] (b-ii) Excitation based on random wave vibration input

[0076] The excitation based on the random wave vibration input is effective mainly in tests assuming a paved road with few bumps and tests simulating vibration input to the vehicle body in an area where the driving speed is relatively high. In addition, the random wave vibration input can measure a wide frequency band for the vibration generated in the vehicle body 100 at once, and is particularly effective in obtaining the vibration characteristics of a high frequency band exceeding 200 Hz where multiple natural vibration peaks appear and are difficult to separate.

[0077] However, when the automobile body 100 is excited by the vibration input of the random wave, it is difficult to control or adjust the phase for each individual frequency of the input wave of the random wave. Figure 3As shown in FIG. 1 , when the vibration input parts 111c and 111d are respectively set at the front and rear of the automobile body 100, the vibration input wave input to the front vibration input part 111c becomes the reference signal of the random wave. And, the vibration input wave input to the rear vibration input part 111d serves as a delayed signal that is delayed by a predetermined delay time with respect to the reference signal.

[0078] That is, when the vibration input wave is a random wave, a reference signal generated by the same signal generating device (oscillation source) such as a function generator is used as the vibration input wave input to the front vibration input part 111c. Furthermore, a delayed signal obtained by delaying the reference signal is used as the vibration input wave input to the rear vibration input part 111d.

[0079] Thus, the automobile body 100 can be excited with random waves of the same waveform and frequency components at the front and rear of the automobile body 100, simulating the vibration of the random waves input to the automobile body when the actual vehicle is running. The delay time given to generate the delay signal can be determined according to the speed of the actual vehicle and the distance between the front and rear wheels (the distance between the front and rear axles).

[0080] As described above, according to the automobile body vibration characteristic test method of this embodiment, it is possible to reproduce the road surface conditions when the actual vehicle is running and the vibration state excited in the automobile body 100 under the driving conditions of the vehicle, and obtain the vibration characteristics such as vibration and noise generated in the automobile body 100. Therefore, in the design stage of the automobile body 100, it is possible to obtain the change in the vibration characteristics of the automobile body 100 accompanying the change of the body structure and materials.

[0081] In addition, in the vibration characteristic test method of the automobile body of the present embodiment, the vibration input wave (input waveform, frequency and amplitude) input to the plurality of vibration input parts 111 and the delay time of the vibration input wave input to each vibration input part can be appropriately changed. As a result, the vibration input conditions for simulating the road surface state and driving conditions (driving speed, etc.) when the actual vehicle is driving can be parameterized, so analytical modeling for CAE analysis becomes easy.

[0082] Furthermore, since it is easy to specify the vibration input waves and their delay times respectively input to a plurality of vibration input locations in the automobile body, the standardization and reproducibility of the vibration input conditions related to the vibration input to the automobile body in the vibration characteristic test are also good.

[0083] <Vibration Characteristics Test Equipment>

[0084] The vibration characteristics test method of this embodiment can be used Figure 4The vibration characteristics test device 1 shown as an example is implemented. Figure 2 The structure of the vibration characteristics test device 1 will be described below with reference to a case where a vibration characteristics test is performed on a vehicle body 100 shown.

[0085] The vibration characteristic test device 1 of this embodiment is used to implement the vibration characteristic test method of this embodiment described above. Figure 4 As shown, a vibration excitation device 10 and a vibration measurement device 20 are provided.

[0086] 《Vibration Device》

[0087] like Figure 2 As shown, the vibration excitation device 10 inputs vibration to a plurality of vibration input locations 111 (111a, 111b) in the automobile body 100 whose body floor 109 is supported by the air cushion 211, thereby exciting the automobile body 100. Figure 4 As shown, the vibration excitation device 10 includes a plurality of vibration exciters 11 ( 11 a , 11 b ), a function generator 13 , a delay processing device 15 , and a plurality of vibration exciter control devices 17 ( 17 a , 17 b ).

[0088] (Vibrator)

[0089] The vibration exciter 11 inputs vibrations of a predetermined input wave (input waveform and frequency of vibration) to each of a plurality of vibration input locations 111 of the vehicle body 100 to perform vibration excitation.

[0090] In this embodiment, a vibration input portion 111a on the right side and a vibration input portion 111b on the left side are provided to the rear of the automobile body 100 (see Figure 2 ) respectively input vibration to the exciter 11a and the exciter 11b (refer to Figure 4 ).

[0091] Moreover, as an example, Figure 5 As shown, each vibrator 11 is installed on the ground 201 via a damping rubber 203. In addition, each vibrator 11 is connected to a mounting bracket 103a via a steel stinger / driving rod 19, and the mounting bracket 103a is bonded to a rear side member 103 which is a part of the chassis of the automobile body 100. Thus, when the vibrator 11 is driven, vibration is input to a vibration input portion 111 set in the rear side member 103 of the automobile body 100 via the stinger / driving rod 19, thereby vibrating the automobile body 100.

[0092] As the exciter 11 , an electro-magnetic exciter can be exemplified, but the present invention is not limited thereto.

[0093] (Function Generator)

[0094] The function generator 13 functions as a signal generating device 13a that generates a plurality of reference signals that are used as references for the input waves of vibrations input to the respective vibration input locations 111 of the automobile body 100. The function generator 13 can appropriately set the waveform and frequency of the reference signal, and can select a sine wave or a random wave as the waveform of the reference signal.

[0095] In this embodiment, if Figure 4 As shown, the function generator 13 generates a vibration input portion 111a on the right side and a vibration input portion 111b on the left side of the rear of the automobile body 100 (see Figure 2 ) are two reference signals P of the reference vibration input wave respectively input A and P B In the following description, the two reference signals P A and P B Collectively referred to as the reference signal P.

[0096] (Delay processing device)

[0097] The delay processing device 15 generates a delay signal that delays a portion of the reference signal generated by the signal generating device 13a. In this embodiment, the delay processing device 15 is incorporated in the function generator 13. Figure 4 As shown, the delay processing device 15 makes the two reference signals P generated by the signal generating device 13a in the function generator 13 A and P B A reference signal P B Delayed to generate a delayed signal Q B .

[0098] (Vibrator control device)

[0099] The exciter control device 17 drives and controls the plurality of exciters 11 respectively using the reference signal generated by the signal generating device 13a or the delay signal generated by the delay processing device 15. Figure 4 As shown, the exciter control device 17a uses the reference signal P generated by the signal generating device 13a. A The exciter 11a is driven and controlled by the exciter control device 17b using the delay signal Q generated by the delay processing device 15. BThe exciter 11 b is driven and controlled. When an electrodynamic exciter is used as the exciter 11 , the exciter control device 17 generates a power input pattern of power to be input to the electrodynamic exciter based on a reference signal or a delay signal.

[0100] As a method of vibrating the automobile body 100 using the vibration excitation device 10, the setting of the vibration input portion is described in the vibration characteristics test method of this embodiment (refer to Figure 2 , Figure 3 ),have Figure 6 Two methods are shown.

[0101] like Figure 6 As shown in (a) of FIG. 1 , the first method is to input vibration to the vibration input parts 111a and 111b respectively set on the right and left sides of the rear of the automobile body 100 to perform excitation. As described above, the first method assumes a vibration state in which vibration is input centered on the rear of the FF vehicle (see FIG. 1 ). Figure 2 ).

[0102] In the first mode, the reference signal P generated by the function generator 13 is input to the vibration exciter control device 17a to drive and control the vibration exciter 11a, and the vibration is input to the vibration input part 111a set on the rear right side of the automobile body 100. In addition, the delay signal Q generated by the function generator 13 is input to the vibration exciter control device 17b to drive and control the vibration exciter 11b, and the vibration is input to the vibration input part 111b set on the rear left side of the automobile body 100. The reference signal P is a sine wave, and the delay signal is a signal obtained by giving a phase difference of 180° to the reference signal P in the function generator 13 to delay the reference signal P.

[0103] like Figure 6 As shown in (b), in the second method, vibration is input to the vibration input parts 111c and 111d respectively set at the front and rear of the automobile body 100. As described above, the second method assumes a vibration state in which vibrations of the same waveform are input to the vehicle from the front and rear tires due to the unevenness of the road surface (see Figure 3 ).

[0104] In the second embodiment, the function generator 13 first generates a reference signal P and a delayed signal Q which delays the reference signal P. The reference signal P is a sine wave, and the delayed signal is a signal delayed by delaying the reference signal P by a delay process which gives the reference signal P a phase difference of 45° (equivalent to a phase angle of -45°).

[0105] Then, the generated reference signal P is input to the vibration exciter control device 17a to drive and control the vibration exciter 11a, and the vibration is input to the vibration input portion 111c set in the front of the vehicle body 100. On the other hand, the generated delay signal Q is input to the vibration exciter control device 17b to drive and control the vibration exciter 11b, and the vibration is input to the vibration input portion 111d set in the rear of the vehicle body 100.

[0106] The above two methods are about generating a delayed signal Q by generating two sinusoidal reference signals using the function generator 13 and giving a phase difference (45° or 180°) to one of the reference signals P to delay it. However, the excitation device of the present invention may generate a plurality of random wave reference signals, perform a delay process of giving a delay time to a part of the generated reference signals, and generate a delayed signal delayed than the reference signal.

[0107] 《Vibration measurement device》

[0108] like Figure 4 As shown, the vibration measuring device 20 measures data related to the vibration characteristics of the automobile body 100 excited by the excitation device 10, and includes an accelerometer 21, an exciting force / input accelerometer 23, and a data recorder 25. In addition, in this embodiment, the vibration measuring device 20 further includes a data processing device 27.

[0109] (Accelerometer)

[0110] The accelerometer 21 is provided in the automobile body 100 and measures the vibration acceleration generated in the automobile body 100 as data related to the vibration characteristics of the automobile body 100. The accelerometer 21 may be provided in a plurality of locations in the automobile body 100.

[0111] (Excitation force / input accelerometer)

[0112] The excitation force / input accelerometer 23 measures the excitation force and input acceleration of the automobile body 100 by vibrating the automobile body 100 using the vibration exciter 11 of the vibration excitation device 10. Figure 5 As shown, the exciting force / input accelerometer 23 is disposed between the exciting rod 19 and the mounting bracket 103a.

[0113] (Data Logger)

[0114] The data recorder 25 obtains the vibration acceleration of the vehicle body 100 measured by the accelerometer 21 and the vibration excitation force and input acceleration input to the vehicle body 100 measured by the excitation force / input accelerometer 23. In this embodiment, the data recorder 25 synchronously obtains the time history data (time trend data) of the vibration acceleration measured by the accelerometer 21 and the time history data of the vibration excitation force and input acceleration measured by the excitation force / input accelerometer.

[0115] (Data processing device)

[0116] The data processing device 27 processes the time history data of the vibration acceleration of the automobile body 100 and the time history data of the vibration exciting force and input acceleration obtained by the vibration measuring device 20 to obtain the vibration characteristics of the automobile body 100. The data processing device 27 may also be constituted by a CPU (central processing unit) of a computer (PC, etc.). In this case, the above-mentioned components function by executing a predetermined program by the CPU of the computer.

[0117] As described above, according to the automobile body vibration characteristic test device of the present embodiment, the automobile body vibration characteristic test method of the present embodiment can be implemented. Thus, the road surface state when the actual vehicle is running and the vibration state excited to the automobile body under the driving conditions of the vehicle can be reproduced, and the vibration characteristics such as vibration and noise generated in the automobile body can be obtained. Moreover, in the design stage of the automobile body, the change of the vibration characteristics of the automobile body accompanying the change of the body structure and material can be obtained.

[0118] In addition, in the automobile body vibration characteristic test device of the present embodiment, the vibration input waves (input waveform, frequency and amplitude) input to the plurality of vibration input parts and the delay time of the vibration input waves input to each vibration input part can be appropriately changed. Thus, the vibration input conditions that simulate the road surface conditions and driving conditions (driving speed, etc.) when the actual vehicle is driving can be parameterized.

[0119] Moreover, in the vibration characteristics testing device of this embodiment, the input wave and delay time of the vibration input to the automobile body 100 using the excitation device 10 can be easily specified, so that the vibration input conditions can be standardized and a vibration characteristics test with good reproducibility can be performed.

[0120] The above description is about the case where the vibration acceleration is measured as the vibration characteristic of the automobile body 100 by the accelerometer installed in the automobile body 100. However, the present invention can also be provided with a microphone inside the automobile body 100 to measure the data related to the noise generated from the automobile body 100. In this case, the sound pressure of the noise is measured by the microphone, and the time history data of the sound pressure is obtained by the data recorder 25. And by processing the time history data of the sound pressure by the data processing device 27, the noise level can be obtained as the vibration characteristic of the automobile body 100.

[0121] In the above-mentioned vibration characteristic test device 1, the delay processing device 15 is assembled in the function generator 13, but it can also be as follows. Figure 7 Like the vibration characteristic test device 3 shown in the figure, it is provided separately from the function generator 31.

[0122] In this case, if Figure 7 As shown in the example, as long as two reference signals P are generated by the function generator 31 A and P B And through the delay processing device 15, a reference signal P B Delay processing is performed to generate a delayed signal Q B Alternatively, the vibration characteristics test device of the present invention may also incorporate a delay processing device (not shown) in a vibration exciter control device that controls the vibration exciter by a delay signal.

[0123] In the present invention, the reference signal input to the vibration exciter control device is a signal serving as a reference among the input waves of vibrations input to each of the plurality of vibration input locations set in the vehicle body. Figure 8 The vibration characteristics test device 5 shown in the example is used to test the reference signal P generated by the signal generating device 13a. A and P B Each of them generates a delayed signal Q through the delay processing devices 15a and 15b. A and Q B In such a vibration characteristic test device 5, the delay signal Q B Delay signal Q A In case of delay, the delayed signal Q A is considered as a reference signal.

[0124] Example 1

[0125] Since a test was conducted to verify the effects of the present invention, this will be described below.

[0126] In this embodiment 1, Figure 2 and Figure 3As shown, the automobile body 100 is placed on four air cushions 211 provided on the ground 201. Then, the vibration characteristics of the automobile body 100 are obtained by inputting vibrations to a plurality of vibration input locations 111 in the automobile body 100 using the vibration characteristics test apparatus 1 according to the embodiment of the present invention described above and exciting the vibrations.

[0127] The automobile body 100 used as the test object is a commercially available compact car (length 4.0 m, width 1.7 m, vehicle weight 1.0 ton, distance between front and rear axles 2.5 m) disassembled to remove components other than the body components such as the drive system, interior, functional components, and electrical components.

[0128] like Figure 2 and Figure 3 As shown, a vehicle body 100 is excited by a vibration excitation device 10 of a vibration characteristics test device 1. The vibration excitation device 10 includes a vibration exciter 11, a function generator 13, and a vibration exciter control device 17.

[0129] The function generator 13 functions as a signal generating device 13a for generating a reference signal and a delay processing device 15 for delaying the reference signal to generate a delay signal. The reference signal or the delay signal generated by the function generator 13 is input to the vibration exciter control device 17 to drive and control the vibration exciter 11, thereby inputting vibration to the automobile body 100. The vibration exciter 11 and the automobile body 100 are connected by a steel vibration rod 19, and an exciting force / input accelerometer 23 is provided between a vibration input portion 111 of the automobile body 100, which is a mounting portion of the vibration rod 19, and the vibration rod 19. In the aforementioned Figure 5 An example of the connection state of the excitation rod 19 and the automobile body 100 is shown in FIG.

[0130] An accelerometer for measuring vibration acceleration is provided on the automobile body 100. The accelerometer is a small piezoelectric type and is bonded to various locations of the automobile body 100 with an adhesive.

[0131] The vibration acceleration detection signal of the accelerometer is simultaneously recorded in a multi-channel data recorder 25 at a sampling frequency of 2.0 kHz to obtain the moment history data of the vibration acceleration. In addition, the obtained moment history data of the vibration acceleration is transformed into a frequency response spectrum by Fourier transform in the data processing device 27 to obtain the frequency and amplitude strength of the natural vibration peak.

[0132] In the first embodiment, a vibration characteristic test was conducted for a plurality of vibration input locations 111 set in the automobile body 100, respectively, when random wave vibration was input and when sine wave vibration was input.

[0133] <Excitation of input waves based on random waves (Part 1)>

[0134] Two engine frame mounting points in front of the vehicle body floor 109 of the vehicle body 100 are set as vibration input parts 111c, and two torsion beam mounting points in the rear are set as vibration input parts 111d (see Figure 3 ). Then, the vibration exciter 11 continuously inputs random wave vibrations to the vibration input portions 111 c at the front and 111 d at the rear for a certain period of time, thereby exciting the automobile body 100.

[0135] The vibration input waves input to the two front and two rear vibration exciters 11 are the same waveform with the same phase. The vibration exciters 11a inputting vibration to the two front vibration input parts 111c are respectively output by the signal generating device 13a in the function generator 13 (refer to Figure 4 ) is input to the vibration exciter control device 17a for driving control. On the other hand, the vibration exciter 11b inputting vibration to the vibration input part 111d at the rear 2 is passed through the delay processing device 15 in the function generator 13 (refer to Figure 4 ) The reference signal P is delayed to generate a delay signal Q which is input to the exciter control device 17b to perform drive control ( Figure 6 (b)).

[0136] The delay signal Q is generated by delaying the reference signal P to delay times of 125 ms and 90 ms, assuming that the actual vehicle travels at speeds of 72 km / h and 100 km / h.

[0137] The vibration characteristics test was conducted for 10 minutes to measure the MID ( Fig.10 The vibration acceleration measured by the accelerometer 21 at the position A7 in the vehicle body 100 is used to obtain the time history data of the vibration acceleration. Then, the obtained time history data of the vibration acceleration is subjected to Fourier transformation to obtain the frequency response spectrum of the vibration acceleration generated in the roof side beam MID of the vehicle body 100.

[0138] Fig. 9The frequency response spectrum of the vibration acceleration generated in the roof side member MID of the automobile body 100 is shown when the delay time of the delay signal Q is set to 125 ms and 90 ms. In the case of the delay time of 125 ms (driving speed of 72 km / h), Fig. 9 As shown in (a), regarding the transfer ratio (ratio of acceleration amplitude) based on the vibration acceleration input to the forward vibration input site 111 c , the peaks near 80 Hz and 160 Hz increase, and the peak near 100 Hz decreases.

[0139] In contrast, when the delay time is 90ms (equivalent to a driving speed of 100km / h), Fig. 9 As shown in (b), the peak values ​​of the transmissibility near 100 Hz and 165 Hz increase, while the peak values ​​near 50 Hz and 128 Hz decrease.

[0140] As described above, in the vibration characteristic test that reproduces the difference in the running speed in the actual vehicle running test, the situation where the vibrations generated in the automobile body 100 are different is reproduced, and the difference in the vibration characteristics with respect to the running speed can be obtained.

[0141] <Excitation by Sine Wave Input Wave>

[0142] The two torsion beam mounting points on the right and left sides of the rear of the automobile body 100 are respectively set as vibration input locations 111a and 111b (refer to Figure 2 ). Then, the automobile body 100 is excited by a method in which the vibration exciter 11 inputs a sine wave vibration of a predetermined frequency to the vibration input parts 111a and 111b for a predetermined period of time to excite steady-state vibration.

[0143] The input wave of vibration input to the vibration input part 111a on the right side (driver's seat side) is set to the reference signal P generated by the function generator 13. On the other hand, the input wave of vibration input to the vibration input part 111b on the left side (passenger seat side) is set to the delayed signal Q which is delayed by giving a phase difference to the reference signal by the delay processing device 15 inside the function generator 13. The waveforms of the reference signal and the delayed signal are both set to sine waves, and the frequency (excitation frequency) thereof is set to the frequency (40 Hz, 48 Hz or 103 Hz) observed as a resonance peak in the frequency response spectrum obtained when the automobile body 100 is excited by the input wave of the random wave.

[0144] In the automobile body 100, an accelerometer 21 for measuring vibration acceleration is arranged at Fig.10The measurement locations A1 to A6 are shown. A1 is the right end of the rear roof header in the left-right direction of the vehicle body, A2 is the right rear part of the vehicle body in the rear floor, and A3 is the center of the front roof header in the left-right direction of the vehicle body. In addition, A4 is the front end of the right front side beam, A5 is the center of the rear floor cross beam in the left-right direction of the vehicle body, and A6 is the center of the right center pillar in the up-down direction of the vehicle body.

[0145] One test lasts for 100 seconds, and the vibration is excited by a sine wave of the same frequency. The vibration acceleration is measured by the accelerometer 21 installed on the automobile body 100A1~A6, and the time history data is obtained by the data recorder. Then, the frequency response spectrum is obtained by Fourier transforming the time history data of the vibration acceleration obtained for each part of A1~A6, and the average value of the peak amplitude is calculated.

[0146] In addition, the vibration input wave input to the vibration input part 111b on the passenger seat side is delayed by giving a phase difference within the range of 0° to 180° to the vibration input wave input to the vibration input part 111a on the driver seat side, and the vibration characteristics of each part A1 to A6 are compared.

[0147] Fig.11 This indicates the peak amplitude intensity obtained when excitation is performed with a phase difference of 0° (no phase difference, synchronous), 90°, and 180°. Fig.11 The peak amplitude intensity shown is expressed as a ratio when the amplitude intensity obtained in the phase difference observed for the main peak is set to 1.0. This is to exclude the difference in amplitude intensity of body parts and positions and focus on the difference in phase difference of the input wave of the vibration input to the vibration input part.

[0148] like Fig.11 As shown, at an excitation frequency of 40 Hz, the peak amplitude intensity at measurement locations A1 and A2 is the maximum amplitude when the phase difference is 180°. In contrast, the peak amplitude intensity at measurement location A3 is less affected by the phase difference. In addition, at an excitation frequency of 48 Hz, the peak amplitude intensity at measurement locations A4 and A5 is the maximum when there is no phase difference (0°), and the peak amplitude intensity decreases as the phase difference increases. Moreover, at an excitation frequency of 103 Hz, the peak amplitude intensity at measurement location A6 records the maximum value when the phase difference is 90°.

[0149] The above shows that the vibration characteristics of the automobile body 100 can be obtained by using the vibration characteristics test of the automobile body as the body-in-white to obtain the vibration characteristics of the automobile body 100 in response to the influence of the low-frequency periodic vibration input transmitted from the left and right rear wheels when the automobile body 100 is traveling on a rough road surface.

[0150] Example 2

[0151] <Excitation of input waves based on random waves (Part 2)>

[0152] In the second embodiment, a vibration characteristic test was conducted on a pavement surface (driving road surface) with few irregularities (e.g., step paving, ramble strips, etc.) with periodic irregularities at intervals shorter than the distance between the front and rear axles of the automobile body 100. In this vibration characteristic test, two vibration input locations 111c at the front and two vibration input locations 111d at the rear were set on the body floor 109 of the automobile body 100 (see Figure 3 ). Then, the vibration exciter 11 continuously inputs random wave vibrations (equivalent to the vibrations input from the paved road surface) to the vibration input portion 111 c and the vibration input portion 111 d for a certain period of time, thereby exciting the automobile body 100 .

[0153] The input waves of vibrations input to the two vibration input parts 111c at the front and the two vibration input parts 111d at the rear are respectively set to the same waveform with the same phase. The exciter 11a that inputs vibrations to the two vibration input parts 111c at the front input is driven and controlled by inputting a reference signal P to the exciter control device 17a. On the other hand, the exciter 11b that inputs vibrations to the two vibration input parts 111d at the rear input is driven and controlled by inputting a delay signal Q to the exciter control device 17b ( Figure 6 (b)).

[0154] When the distance between the axles is equal to the interval between the periodic road surface bumps, the vibration of the random wave input from the tire to the vehicle body is equivalent to the case where it is input at the same timing (phase synchronization) at the front and rear of the vehicle body 100. On the other hand, when the interval between the periodic road surface bumps is shorter than the distance between the axles, the delay time of the delay signal Q is determined in such a way that the input timing at the rear side is delayed compared to the front side of the vehicle body 100 in accordance with the driving speed.

[0155] In the second embodiment, the distance between the axles of the automobile body 100 is assumed to be 2500m, the actual vehicle speed is 100km / h, and the intervals of the periodic road surface bumps are 1860mm, 2180mm, and 2330mm, and the delay time of the delay signal Q is determined to be 23.0ms, 11.5ms, and 6.1ms, respectively. Then, the reference signal P is delayed according to these delay times to generate the delay signal Q.

[0156] In the automobile body 100, an accelerometer 21 for measuring vibration acceleration is arranged at Fig.12The measurement positions of A3, A8 to A10 are shown. A3 is the center of the front roof head in the left-right direction of the vehicle body, A8 is the center of the roof crossbar in the left-right direction of the vehicle body. Moreover, A9 is the center of the rear panel in the left-right direction of the vehicle body, and A10 is the center of the lower longitudinal sill inner member in the front-rear direction of the vehicle body.

[0157] The vibration characteristic test lasts for 10 minutes, and the vibration is excited by a random wave of the same waveform, and the vibration acceleration measured by the accelerometer 21 installed in A3, A8~A10 of the automobile body 100 is measured to obtain the moment history data of the vibration acceleration. Then, by performing Fourier transform on the obtained moment history data of the vibration acceleration, the frequency response spectrum of the vibration acceleration generated in A3, A8~A10 is obtained.

[0158] Fig.13 A graph showing the frequency response spectra of vibration acceleration generated at (i) A3, (ii) A8, (iii) A9, and (iv) A10. Fig.13 In the figure, the horizontal axis is the frequency of vibration acceleration (Hz), and the vertical axis is the transfer ratio of vibration acceleration (m / s 2 ) / (m / s 2 )).in addition, Fig.13 (a) is the result of the frequency response spectrum in the frequency band 20~100Hz. Fig.13 (b) is the result of the frequency response spectrum in the frequency band of 100~400Hz. Fig.13 The frequency band 20 to 100 Hz in (a) is a low-frequency band in the audible frequency band. Fig.13 The frequency band 100~400Hz of (b) is related to Fig.13 The frequency band of (a) is a frequency band in which the noise in the vehicle cabin becomes a problem, and is higher than the human auditory sensitivity.

[0159] In the case of a frequency band of 20~100Hz, if Fig.13 As shown in (a), it can be seen that if the delayed signal Q of the vibration input to the vibration input part 111d at the rear of the automobile body 100 is changed between the delay time 6.1ms and 23.0ms, the frequency response spectrum distribution changes, and the frequency (peak frequency) with the highest transmission rate changes. For example, Fig.13 In the frequency response spectrum of the vibration acceleration generated by A3 shown in (a)(i), the peak frequencies at delay times of 6.1 ms, 11.5 ms, and 23.0 ms change to 69 Hz, 47 Hz, and 41 Hz, respectively.

[0160] In contrast, in the case of a frequency band of 100 to 400 Hz, if Fig.13As shown in (b), the frequency response spectrum distribution does not change as in the 20-100 Hz band, but the transmission rate of a specific frequency increases with the delay time. Fig.13 In the frequency response spectrum of the vibration acceleration generated by A10 in (b) (iv), the transmissibility at 240-290 Hz and 310 Hz increases when the delay time is set to 11.5 ms and 23.0 ms compared to 6.1 ms.

[0161] As described above, it can be seen that the frequency response spectrum also changes significantly by changing the delay time of the delay signal Q to the rear of the automobile body 100. This result shows that according to the present invention, the vibration and noise conditions felt by the driver can be reproduced and evaluated in which the intervals of periodic road surface unevenness are different.

[0162] Industrial availability

[0163] According to the present invention, a vehicle body vibration characteristic test method and apparatus can be provided which can appropriately reproduce the road surface state and vehicle driving conditions when a real vehicle is driving to obtain the vibration characteristics of the vehicle body.

[0164] Description of symbols

[0165] 1. Vibration characteristics test device

[0166] 3 Vibration characteristics test device

[0167] 5 Vibration characteristics test device

[0168] 10. Vibration device

[0169] 11. Vibrator

[0170] 11a Vibrator

[0171] 11b Vibrator

[0172] 13 Function Generator

[0173] 13a Signal generating device

[0174] 15 Delay processing device

[0175] 15a Delay processing device

[0176] 15b Delay processing device

[0177] 17 Vibrator control device

[0178] 17a Vibrator control device

[0179] 17b Vibrator control device

[0180] 19 Vibration rod

[0181] 20 Vibration measuring device

[0182] 21 Accelerometer

[0183] 23 Excitation force / input accelerometer

[0184] 25 Data Logger

[0185] 27 Data processing device

[0186] 30 Excitation device

[0187] 31 Function Generator

[0188] 40 Excitation device

[0189] 41 Function Generator

[0190] 100 Car body

[0191] 101 Front side beam

[0192] 103 Rear side beam

[0193] 103a Mounting bracket

[0194] 105 Bumper reinforcement

[0195] 107 Rear floor beam

[0196] 109 Body floor

[0197] 111 Vibration input part

[0198] 111a Vibration input part

[0199] 111b Vibration input part

[0200] 111c Vibration input part

[0201] 111d Vibration input part

[0202] 201 Ground

[0203] 203 Anti-vibration rubber

[0204] 211 Air cushion.

Claims

1. A method for testing the vibration characteristics of an automobile body, wherein vibration is input to the automobile body to obtain the vibration characteristics of the automobile body, wherein: include: a vibration excitation step of setting a plurality of vibration input locations on the automobile body supported by the air cushion, and inputting vibration to each of the plurality of vibration input locations to vibrate the automobile body; and a vibration measuring step of measuring data related to vibration characteristics of the automobile body excited in the vibration exciting step, In the vibration excitation step, the vibration input wave input to a part of the vibration input locations in the vehicle body is delayed compared to the vibration input waves input to the other vibration input locations.

2. The vibration characteristic test method of an automobile body according to claim 1, wherein: In the excitation process, The vibration input portion is set on the right and left sides of the rear of the automobile body, generating a plurality of reference signals of sine waves or random waves as references of the input waves of the vibrations input to the respective vibration input portions, generating a delay signal by delaying a part of the generated plurality of reference signals, inputting vibration using the reference signal as an input wave to the vibration input portion on either the left side or the right side of the rear of the vehicle body, The vibration input portion on the other of the left and right sides of the rear of the vehicle body receives vibration having the delayed signal as an input wave.

3. The vibration characteristic test method of an automobile body according to claim 1, wherein: In the excitation process, The vibration input portion is set at the front and rear of the automobile body, generating a plurality of reference signals of sine waves or random waves as references of the input waves of the vibrations input to the respective vibration input portions, generating a delay signal by delaying a part of the generated plurality of reference signals, inputting vibration with the reference signal as an input wave to the vibration input portion in front of the vehicle body, Vibration using the delayed signal as an input wave is input to the vibration input portion at the rear of the automobile body.

4. The vibration characteristic test method of an automobile body according to any one of claims 1 to 3, wherein: In the vibration measurement process, an accelerometer is set on the car body to measure the vibration acceleration generated in the car body as data related to the vibration characteristics, and / or a microphone is set inside the car body to measure the sound pressure of the noise generated from the car body as data related to the vibration characteristics.

5. A vibration characteristic test device for an automobile body, which inputs vibration into the automobile body to obtain the vibration characteristics of the automobile body, wherein: have: a vibration excitation device for vibrating the vehicle body by inputting vibration to each of a plurality of vibration input locations set in the vehicle body supported by the air cushion; and a vibration measuring device for measuring data related to vibration characteristics of the automobile body excited by the vibration exciting device, The vibration excitation device comprises: A plurality of vibration exciters for inputting vibrations of a predetermined input wave to a plurality of the vibration input locations in the vehicle body to perform vibration excitation; A signal generating device for generating a plurality of reference signals serving as references for input waves of vibrations input to the respective vibration input portions; A delay processing device delays a part of the generated plurality of reference signals to generate a delayed signal; as well as A plurality of vibration exciter control devices are used to drive and control the plurality of vibration exciters respectively through the generated reference signal or delay signal. The vibration measuring device comprises: an accelerometer disposed on the vehicle body and measuring vibration acceleration generated on the vehicle body, and / or a microphone disposed inside the vehicle body and measuring data related to noise generated from the vehicle body; an exciting force / input accelerometer for measuring an exciting force and an input acceleration for exciting the vehicle body by vibration input into the vehicle body; as well as The data recorder acquires the vibration acceleration measured by the accelerometer and / or the sound pressure of the noise measured by the microphone, and the excitation force and input acceleration measured by the excitation force / input accelerometer.

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