JP2018163042A - Dynamic rigidity test method for automobile body - Google Patents

Abstract

An object of the present invention is to provide a method for testing a dynamic rigidity of a vehicle body, which is correlated with the steering stability of the vehicle. Kind Code: A1 A dynamic rigidity test method for an automobile body according to the present invention includes a table with a slide mechanism capable of fixing an automobile body, a table with a slide mechanism vibrated in a horizontal acceleration direction in a predetermined acceleration pattern. A vibrating device 5 that suppresses and brakes vibrations outside the control of the slide mechanism-equipped table 3 using a vibration device 5 that vibrates the slide mechanism-equipped table 3 to which the vehicle body 21 is fixed, A braking step S3 in which the vibration of the table 3 with the slide mechanism due to the vibration of the vehicle body 21 outside the control is suppressed and braking is performed, and an amount of energy input to the vibration device 5 in a predetermined section between the vibration step S1 and the braking step S3 is measured. Input energy amount measuring step S5 and an evaluation step S7 for evaluating the dynamic rigidity of the vehicle body 21 based on the measured input energy amount. The is characterized in that it comprises. [Selection diagram] Fig. 1

Description

  The present invention relates to a method for testing dynamic rigidity of an automobile body, and more particularly, to a method for testing dynamic rigidity of an automobile body, in which dynamic rigidity is evaluated by applying vibration in the width direction of the automobile body.

  Conventionally, as described in Patent Document 1, the rigidity of the automobile body is fixed at the left and right damper mounting positions on either the front side or the rear side of the automobile body, and the left and right suspension fastenings on the opposite side are not fixed. In general, evaluation is performed by a torsional rigidity test in which actuators are connected to the respective parts, the left and right actuators are moved in opposite phases, the entire automobile body is twisted, and the torsion angle at a constant load is measured. The rigidity evaluated by such a torsional rigidity test is a static evaluation value, and as disclosed in Patent Document 2, it is useful for evaluating the rigidity of an automobile body as a structure. It is applied to the evaluation of the left and right shaking feeling in the running test. However, it cannot be said that the correlation with the sensory evaluation values such as the steering stability and the riding comfort at the time of the steering evaluated by the driving test of the actual vehicle by the test driver is not sufficient.

  The sensory evaluation value evaluated by a running test of an actual vehicle is largely determined by the rigidity of the body structure (body frame structure), and the contribution of the undercarriage such as tires and suspensions and the chassis structure is large. However, in a vehicle in which the rigidity of the automobile body is not sufficient, the sensory evaluation value cannot be satisfied only by adjusting the chassis structure.

  In order to obtain an index close to a sensory evaluation value by a lab-scale rigidity test using an automobile body as a test object, it is important to measure at least the dynamic deformation behavior of the automobile body with respect to fluctuations in load. In order to measure the dynamic deformation behavior, for example, a cyclic torsional deformation is given to the vehicle body by continuously changing the load load in the above-described torsional rigidity test, and the change in the torsion angle at that time or the vehicle body A method for measuring the deformation behavior of each part is conceivable. Data obtained by such a torsional rigidity test on a lab scale is useful for deformation behavior when a load is input in the vertical direction of the vehicle due to a road step through a tire and a suspension.

When the direction of vehicle movement is changed, such as cornering or lane change, the power train or chassis transmits lateral (vehicle width direction) force to the vehicle body, and the entire vehicle changes the direction of movement. The vehicle body has high rigidity, and when the entire vehicle approaches a rigid body, the vehicle can smoothly change the direction of motion. In a vehicle body with low rigidity, elastic deformation occurs in the vehicle body due to instantaneous lateral force, and a time delay occurs in the movement of the entire vehicle. When the driver feels this time delay, the driver tends to perform an extra steering operation, which requires a larger steering angle and steering force than a rigid vehicle body.
Therefore, in order to evaluate the rigidity of the vehicle body that is correlated with sensory evaluation values such as steering stability and riding comfort, it is necessary to know the deformation behavior of the vehicle body when a load is applied in the vehicle body width direction described above. Necessary.

  As a method for knowing the deformation behavior of the vehicle body when a load is applied in the vehicle body width direction, for example, Patent Document 3 discloses a technique for measuring rigidity by inputting a load to each part of the vehicle body. According to this technique, it is possible to arbitrarily set a portion and a direction for inputting a load.

JP 2006-292737 A Japanese Patent Laying-Open No. 2015-161588 JP 2006-284340 A

  As in the technique disclosed in Patent Document 1 or Patent Document 2, in a torsional rigidity test that has been generally performed in the past, a static rigidity value of an automobile body as a structure can be obtained. A dynamic stiffness value when a load is applied cannot be obtained, and the correlation with sensory evaluation items during actual driving such as steering stability and riding comfort is weak.

  The technique disclosed in Patent Document 3 evaluates the rigidity including the vehicle body width direction. However, the frequency response of the vehicle body provided with the forced vibration and the eigenvalue analysis which are implemented as the modal analysis are used, and the frequency of 30 Hz or more is used. This is a region-based stiffness test that analyzes vibration behavior in a steady state. For this reason, there is a strong correlation with vehicle performance evaluation items related to vehicle vibration and road noise, but it is not suitable for dynamic stiffness evaluation related to sensory evaluation values such as steering stability in an unsteady state such as steering. It is enough.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a method for testing the dynamic rigidity of an automobile body that obtains the dynamic rigidity of the automobile body having a correlation with the steering stability of the vehicle. To do.

  Among vehicle performance, steering stability is considered to have a strong correlation with vehicle response behavior during cornering and lane change. Unsteady transient (dynamic) vehicle body deformation due to load acting in the vehicle width direction It depends greatly on the behavior. In particular, from the viewpoint of stability at the time of lane change, vibration damping behavior in the process of restoring the deformation of the vehicle body after the load acting on the vehicle body when cornering or lane change is finished is important.

  Therefore, the inventor applies a load by applying vibration in the vehicle body width direction of the automobile body using the vibration device, and the dynamics of the automobile body from the vibration damping behavior due to the restoration in the vehicle body deformation generated in the automobile body by the load. We examined a method to obtain a numerical index for sensory evaluation such as steering stability without evaluating the actual vehicle by evaluating the rigidity.

  Specifically, the vehicle body to be evaluated is fixed to a table with a slide mechanism that can move in one horizontal axis, and the table with the slide mechanism is vibrated and moved in one direction before being braked. A test was carried out to directly measure the vibration damping behavior of the deformation of the vehicle body by applying a load in the vehicle body width direction of the vehicle body by the vibration device made.

However, when the weight ratio of the table with the slide mechanism is large as in the case of an automobile body, the center of gravity of the automobile body is high from the position of the table with the slide mechanism and the moment arm is long, the automobile body in the process of braking after vibrating the automobile body It was found that out-of-control vibration was generated in the table with the slide mechanism due to the influence of deformation vibration. That is, when the table with the slide mechanism on which the automobile body is mounted is braked against the braking of the table with the slide mechanism on which the automobile body is not mounted, vibration is generated when the automobile body is elastically deformed and restored. This vibration caused by the automobile body is out of control.
When such out-of-control vibrations occur, it becomes difficult to separate the vibrations of the table with the slide mechanism itself by interfering with the vibration damping behaviors of the car body deformation, and based on the measurement results of the vibration damping behavior of the car body deformation. It is difficult to accurately evaluate the dynamic stiffness.

Therefore, the inventor further scrutinizes the vibration outside the control of the table with the slide mechanism as described above, and in order to suppress the vibration of the table with the slide mechanism from causing the vibration outside the control due to the vibration of the automobile body deformation We paid attention to the ability to drive and control the vibration device.
Furthermore, the lower the rigidity of the car body, the greater the influence of vibration damping, and the knowledge that the amount of energy input to the vibration device is increasing to suppress vibration outside the control of the table with the slide mechanism has been obtained. . In other words, it is conceived that the dynamic rigidity of the car body can be evaluated by indirectly measuring the vibration damping behavior of the car body deformation by the amount of energy input to the vibration device in order to suppress the vibration outside the control. That is why.
The present invention has been made based on such studies, and specifically has the following configuration.

(1) A method for testing a dynamic rigidity of an automobile body according to the present invention includes a table with a slide mechanism that can fix an automobile body, and vibrates the table with a slide mechanism in a horizontal uniaxial direction with a predetermined acceleration pattern and the slide mechanism. A vibration device that can suppress and suppress vibration outside the control of the attached table, and the vibration step of vibrating the table with the slide mechanism to which the vehicle body is fixed in a predetermined acceleration pattern; A braking step for braking by suppressing vibration outside the control of the table with the slide mechanism, which is generated by the influence of vibration of the vehicle body, and the vibration device in a predetermined section between the vibration step and the braking step. An input energy amount measuring step for measuring the input energy amount input to the drive, and an investment measured in the input energy amount measuring step. It is characterized in that it comprises an evaluation step of evaluating the dynamic stiffness of the automobile body by the energy amount.

(2) In the device described in (1) above, the input energy amount measuring step measures the input energy amount input to drive the vibration device in the braking step.

(3) In the device described in (1) or (2) above, the vibration device is an electrodynamic vibration device, and the input energy amount measurement step is performed in order to drive the electrodynamic vibration device. The input power amount is measured as the input energy amount.

(4) In the device described in (1) or (2) above, the vibration device is an electrodynamic vibration device, and the input energy amount measuring step is performed to drive the electrodynamic vibration device. A value obtained by time-integrating a time response curve of a signal voltage or a signal current for controlling the input power to be measured is measured as the input energy amount.

(5) The apparatus according to any one of (1) to (4), further comprising a reference input energy amount acquisition step of acquiring a reference input energy amount by measuring an input energy amount measured for a reference automobile body. The evaluation step is characterized in that the evaluation is performed based on a relative ratio between the reference input energy amount and the input energy amount.

(6) In the device according to any one of (1) to (5), the evaluation step calculates the input energy amount input in the braking step from the start of the vibration step to the end of the braking step. It is characterized by normalization based on the amount of energy input.

  In the present invention, the table with the slide mechanism that can fix the automobile body, and the table with the slide mechanism are vibrated in a single horizontal axis direction with a predetermined acceleration pattern, and the vibration is controlled by suppressing the vibration outside the control of the table with the slide mechanism. A vibration device capable of vibrating the table with the slide mechanism, to which the vehicle body is fixed, with a predetermined acceleration pattern, and then the slide generated due to the influence of the vibration of the vehicle body An input energy for measuring an input energy input to drive the vibration device in a predetermined section between the excitation process and the braking process, and a braking process for suppressing the vibration outside the control of the table with the mechanism. The vehicle body by the amount measuring step and the input energy measured in the input energy amount measuring step It is possible to evaluate the dynamic rigidity when a load is applied in the vehicle body width direction of the automobile body, without performing a running test of an actual vehicle. A numerical index related to steering stability can be obtained.

It is a figure explaining the flow of a process of the dynamic rigidity test method of the motor vehicle body which concerns on embodiment of this invention. It is a figure explaining the dynamic rigidity testing apparatus of the motor vehicle body used in this Embodiment (the 1). It is a figure explaining the dynamic-rigidity testing apparatus of the motor vehicle body used in this Embodiment (the 2). It is a figure explaining the electrodynamic vibration apparatus used as a vibration apparatus in the dynamic rigidity test method of the motor vehicle body which concerns on this Embodiment. It is a figure explaining the flow of a process which determines the input electric power pattern input into an electrodynamic vibration apparatus in the dynamic rigidity test method of the motor vehicle body which concerns on this Embodiment. 5 is a graph for explaining input power supplied for driving an electrodynamic vibration device used as a vibration device in the method for testing the dynamic rigidity of an automobile body according to the present embodiment. 5 is a graph showing input power input for driving an electrodynamic vibration device used as a vibration device and acceleration and displacement of a table with a slide mechanism in the method for testing dynamic rigidity of an automobile body according to the present embodiment. . In an Example, it is a figure which shows the state which mounted | wore the automobile body with the stiffening part. In an Example, it is a figure which shows the measurement result of the acceleration pattern and acceleration of a target acceleration pattern with respect to the vehicle body without a stiffening component, and a table with a slide mechanism. In an Example, it is a measurement result of the input electric power input into the electrodynamic vibration apparatus for the vibration and braking of the vehicle body without a stiffening part. In an Example, it is a figure which shows the result of the input electric energy measured about the motor vehicle body which applied the stiffening part.

  The vehicle body dynamic stiffness test method according to the embodiment of the present invention is performed using a vehicle body dynamic stiffness test apparatus 1 (hereinafter, simply “dynamic stiffness test apparatus 1”) as shown in FIG. Is. Therefore, the vehicle body 21 and the dynamic stiffness test apparatus 1 to be tested will be described.

<Auto body>
The automobile body 21 to be tested in the present invention is a so-called white body (body-in-white) that does not include chassis, suspension parts, drive system parts, interior parts, etc., and fastens the vehicle body floor and suspension. A suspension mount portion.

<Dynamic stiffness testing device>
As shown in FIG. 3, the dynamic stiffness test apparatus 1 is configured to vibrate and brake the table 3 with a slide mechanism that can fix the automobile body 21 and the table 3 with the slide mechanism in a horizontal one-axis direction with a predetermined acceleration pattern. It is provided with the vibration device 5 that can be controlled in a simple manner.

The table 3 with a slide mechanism fixes the automobile body 21 and linearly moves in the body width direction of the automobile body 21. For example, as shown in FIG. 3, the vibration table 7 that fixes the automobile body 21, and the automobile body It is possible to use a linear guide 9 capable of linear motion in the vehicle body width direction 21.
The vehicle body 21 is fixed to the table 3 with the slide mechanism at a portion that can be an input point of force when traveling on an actual vehicle, such as a vehicle body floor portion or a suspension mount portion. However, the portion for fixing the vehicle body 21 may be appropriately selected mainly on the vehicle body floor portion, the suspension mount portion, and the like according to the content and purpose of evaluating the characteristics of the vehicle body 21.

  The vibration device 5 vibrates the table 3 with a slide mechanism to which the vehicle body 21 is fixed in a horizontal uniaxial direction with a predetermined acceleration pattern, and elastically deforms the vehicle body 21 by applying a load in the vehicle body width direction. The table is connected to the table 3 with the slide mechanism via the movable part 11.

As the vibration device 5, an electrodynamic vibration device 13 shown in FIG. 4 may be used.
The electrodynamic vibration device 13 drives the drive coil in the operation direction shown in FIG. 4 by a force generated by applying a predetermined current to the drive coil in a magnetic field generated by the excitation coil.
When the electrodynamic vibration device 13 is used as the vibration device 5 shown in FIG. 2, the movable portion 11 having a drive coil is connected to the table 3 with the slide mechanism, thereby sliding along with the drive of the electrodynamic vibration device 13. The mechanism-equipped table 3 is vibrated.

The electrodynamic vibration device 13 includes a control device that drives the electrodynamic vibration device 13 in order to drive it with a target acceleration pattern. As the control device, for example, the table 3 with a slide mechanism to which the vehicle body 21 is fixed is subjected to vibrations of multiple frequencies such as frequency sweep and white noise to measure response behavior in advance, and the table 3 with a slide mechanism is A device having a function of generating an input power pattern to be input to the electrodynamic vibration device 13 for exciting and braking with an acceleration pattern or a displacement pattern may be used.
Furthermore, it is preferable that the control device also has a function of outputting actual data of input power input to drive the electrodynamic vibration device 13.

<Dynamic rigidity test method for automobile bodies>
Next, a dynamic stiffness test method for an automobile body according to an embodiment of the present invention (hereinafter simply referred to as “dynamic stiffness test method”) will be described together with the operation of the dynamic stiffness test apparatus 1.

  The dynamic stiffness test method according to the present embodiment uses the dynamic stiffness test apparatus 1 shown in FIG. 2, and as shown in FIG. 1, a table 3 with a slide mechanism to which an automobile body 21 is fixed. Excitation process S1 that vibrates with a predetermined acceleration pattern, and then braking process S3 that suppresses and suppresses vibration outside the control of the table 3 with the slide mechanism that is caused by the influence of the vibration of the automobile body 21, and the excitation process S1 To an input energy amount measuring step S5 for measuring the input energy amount input to drive the vibration device 5 in a predetermined section between the braking step S3 and the input energy measured in the input energy amount measuring step S5. And an evaluation step S7 for evaluating the dynamic rigidity.

<Excitation process>
The vibration process S <b> 1 is a process in which the vibration device 5 is used to vibrate with a constant acceleration pattern based on the table 3 with a slide mechanism to which the vehicle body 21 is fixed. In the vehicle body 21, the table 3 with a slide mechanism is used. Force is transmitted in the width direction of the vehicle body through the fixed portion, and elastic deformation occurs.

  The vibration device 5 needs to vibrate with a constant acceleration pattern based on the table 3 with the slide mechanism. For this purpose, it is necessary to generate a pattern of input energy that is input to drive the vibration device 5. Hereinafter, a case where the table 3 with a slide mechanism is vibrated with an acceleration pattern of a single pulse wave by the electrodynamic vibration device 13 will be described as an example (FIG. 5).

  First, the transfer function (response function for each frequency) of the table 3 with a slide mechanism to which the automobile body 21 is fixed is measured (S11), and the electrodynamic vibration device 13 is set with a predetermined acceleration pattern based on the measured transfer function. A control constant for driving is determined (S13).

Next, using the determined control constant, a control program (input power pattern shown as an example in FIG. 6) for driving and controlling the electrodynamic vibration device 13 to drive with an acceleration pattern is generated (S15).
By driving the electrodynamic vibration device 13 with the control program determined as described above (S17), the table 3 with the slide mechanism can be vibrated with a constant acceleration pattern serving as a reference for the single pulse wave.

FIG. 6 shows an example of the input power pattern generated by the above procedure.
The input power pattern shown in FIG. 6 gives acceleration in a pulse manner 2.5 seconds after the start of the test. Before the acceleration is given in a pulse manner, the table 3 with a slide mechanism is pre-accelerated, There is a step of suppressing vibrations by braking the table 3 with the slide mechanism after applying the acceleration, and in any step, the electrodynamic vibration device 13 is driven by supplying electric power.

FIG. 7 shows the measurement result of the acceleration of the table 3 with the slide mechanism when the electrodynamic vibration device 13 is driven with the input power pattern shown in FIG. As shown in FIG. 7, the table 3 with a slide mechanism is subjected to preliminary acceleration, and then a half-sine-shaped single pulse acceleration having a maximum acceleration of 6.0 m / s ² is applied.

<Braking process>
The braking step S3 is a step of suppressing the uncontrolled vibration of the table 3 with the slide mechanism due to the influence of the vibration of the automobile body 21 after the vibration step S1.

  As shown in FIG. 7, when a single pulse acceleration is applied to the table 3 with a slide mechanism in the vibration step S1, the electrodynamics is applied so as to brake in a phase opposite to the vibration of the table 3 with a slide mechanism in the braking step S3. Input power is input to the vibration device 13 and braking is performed while suppressing vibration of the table 3 with the slide mechanism.

  Here, in the process of braking the table 3 with the slide mechanism, as described above, the weight ratio of the automobile body 21 with respect to the table 3 with the slide mechanism is large, the position of the center of gravity is high, and the moment arm is long. Due to the influence of the vibration caused by the recovery of the elastic deformation of the automobile body 21 caused by the above, vibration outside the control occurs in the table 3 with the slide mechanism. When such out-of-control vibration occurs, it interferes with the vibration damping behavior of the automobile body 21, and as shown in FIG. 7, the vibration pattern of the table 3 with the slide mechanism is disturbed (2.7 seconds to 3.0 seconds). ).

  Therefore, in the braking step S3, in addition to the input energy that is input to the vibration device 5 to brake the table 3 with the slide mechanism, the input energy that drives the vibration device 5 to suppress the vibration outside the control described above is included. By further applying, the vibration of the table 3 with the slide mechanism is suppressed and sufficiently converged.

<Input energy measurement process>
The input energy amount measuring step S5 is a step of measuring the input energy amount input to the vibration device 5 in a predetermined section between the vibration step S1 and the braking step S3.
The predetermined section for measuring the input energy amount is all or a part of the vibration process S1 to the braking process S3, and the partial section is, for example, the table 3 with the slide mechanism in the braking process S3. It can be set as the area which suppresses vibration of (refer FIG. 6).

  Further, when measuring the input energy amount in the braking step S3, a predetermined interval can be set from the start of the braking step S3 until an arbitrary time elapses. The predetermined interval is the vibration of the table 3 with the slide mechanism. What is necessary is just to set suitably according to a behavior.

  When the electrodynamic vibration device 13 is used as the vibration device 5, the input energy amount measured in the input energy amount measurement step S5 is the input power input to drive the electrodynamic vibration device 13 in the braking step S3. It is only necessary to measure the input electric energy obtained by integrating the time with respect to the above interval.

  Further, the control signal (signal current or signal voltage) for controlling the input power for driving the electrodynamic vibration device 13 is not limited to that obtained by directly measuring the input power input to the electrodynamic vibration device 13 and integrating the time. ) Is measured, and a value obtained by time integration of the predetermined section in the time response curve of the control signal is measured as the input energy amount. Thereby, even if it is difficult to directly measure the input power because a large amount of power is used to drive the electrodynamic vibration device 13, the input energy amount can be easily measured.

<Evaluation process>
The evaluation step S7 is a step of evaluating the dynamic rigidity of the vehicle body 21 based on the input energy amount measured in the input energy amount measurement step S5. When the measured input energy amount is large, the rigidity of the vehicle body 21 is evaluated. If the measured input energy amount is small, it is evaluated that the rigidity of the automobile body 21 is high.

  Here, by using the input energy amount input in the braking step S3 as the measured input energy amount, it is possible to more accurately consider the influence of vibration outside the control caused by the vibration damping behavior of the automobile body 21. Therefore, it is preferable because the dynamic rigidity of the automobile body 21 can be accurately evaluated.

  Further, in the evaluation step S7, the input energy amount input in the braking step S3 is normalized by the input energy amount input from the start of the vibration step S1 to the end of the braking step S3, and expressed by these ratios, for example, The dynamic rigidity of automobile bodies with different weights can be directly compared.

  As described above, the vehicle body dynamic stiffness test method according to the present embodiment includes the above-described steps, and can be used as an index for sensory evaluation such as steering stability and riding comfort without performing a running test of an actual vehicle. A physical numerical index of dynamic stiffness can be obtained. Furthermore, even at the vehicle body skeleton design stage, the performance standards and targets required for the automobile body are clarified, making it easy to build vehicle performance.

  The vehicle body dynamic stiffness test method according to the present embodiment may further include a reference input energy amount acquisition step S9 (see FIG. 1) described below.

<Standard input energy acquisition process>
In the reference input energy amount acquisition step S9, the excitation step S1 and the braking step S3 are performed on the reference automobile body used as a reference for dynamic rigidity evaluation in the same manner as the above-described automobile body 21, and the excitation step S1 to the braking step S3 are performed. This is a step of measuring, as a reference input energy amount, an input energy amount input to drive the vibration device 5 within a predetermined interval.

In this case, in the evaluation step S7, based on the relative ratio between the reference input energy amount acquired in the reference input energy amount acquisition step S9 for the reference automobile body and the input energy amount measured in the input energy amount measurement step S5 for the automobile body 21. The dynamic rigidity of the automobile body 21 is evaluated.
Thus, by obtaining the relative ratio between the reference input energy amount and the input energy amount, for example, the effect of improving the rigidity by attaching the stiffening parts to the automobile body 21 and the rigidity of different automobile bodies based on a certain reference Can be compared with each other.

  In the above description, an example in which the electrodynamic vibration device 13 is used as the vibration device 5 is shown. However, the vibration device 5 is capable of vibrating and braking the table 3 with the slide mechanism with a predetermined acceleration pattern. For example, not only the electrodynamic vibration device 13 but also a device having a drive system such as a hydraulic type or a motor type can be used, and specifications such as vibration frequency, load, and stroke satisfy the test conditions. There are no special restrictions.

  For example, when a hydraulic vibration device is used, the control function that vibrates with a predetermined acceleration pattern or displacement pattern using a servo valve, and the actual data of the input energy input to drive the vibration device is used as the actual data of the hydraulic pressure and the servo valve. Any device having a function of outputting data such as opening and closing may be used. In this case, the input energy amount can be estimated from the control data for opening and closing the servo valve for controlling a predetermined acceleration pattern without measuring the hydraulic pressure of the hydraulic vibration device.

  In addition, when using a motor-type vibration device, for example, a control function that vibrates with a predetermined acceleration pattern or displacement pattern by a pulse motor, and a function that outputs input power input to drive the pulse motor as performance data. What is necessary is just to have. In this case, the input power amount obtained from the power input to drive the motor can be measured as the input energy amount.

  Furthermore, the dynamic stiffness test apparatus 1 may be provided with an accelerometer or a displacement meter that detects the operation of the table 3 with a slide mechanism as necessary, in addition to the above configuration.

<Relationship with sensory evaluation by actual vehicle running test>
The reason why a physical numerical index having a correlation with sensory evaluation such as steering stability and riding comfort can be obtained by the method for testing dynamic rigidity of an automobile body according to the present embodiment will be described below.

When the vehicle travels on a route determined in a running test of an actual vehicle, the chassis including the tire follows the travel route under the control of the driver, and the body fixed to the chassis moves in various directions from front to rear, left and right from the connection point with the chassis. Power is transmitted.
In the dynamic stiffness test apparatus 1, the automobile body 21 is fixed to the table 3 with a slide mechanism at a position such as a vehicle body floor portion or a suspension mount portion that can serve as a force input point when the actual vehicle travels. Table 3 can be thought of as simulating a chassis that conveys changes in the direction and speed of movement of the vehicle to the vehicle body skeleton during vehicle travel.

  The driving test is a sensory evaluation of driving stability, riding comfort, etc., traveling along a predetermined driving route. If the purpose is to evaluate the influence of the body on the same platform, the input load transmitted from the chassis to the body. It is assumed that the directions are almost the same, and the difference in response behavior and characteristics of the body when receiving the same input load and the direction is an evaluation index for sensory evaluation.

  When evaluating whether a vehicle can pass without departing from a predetermined driving route such as a double lane change as a driving test, the driver's steering operation varies greatly depending on the vehicle behavior including body characteristics, and steering stability as a sensory evaluation Also changes. In particular, when traveling under conditions near the limit value, lateral stress is generated in a direction deviating from a predetermined traveling path due to inertial force acting on the body or a response delay, and the vehicle behavior is likely to be disturbed. The driver perceives the disturbance of the vehicle behavior and avoids deviation from the course by an additional steering operation (correction steering). Under the same driving conditions, it can be determined that the vehicle with fewer additional steering operations has better steering stability.

Here, the additional steering operation in the running test is performed by the vibration device 5 in order to suppress the vibration outside the control of the table 3 with the slide mechanism shown in FIG. 2 in the method for testing the dynamic rigidity of the automobile body according to the present embodiment. It is considered that it corresponds to the amount of energy input to.
That is, after the target pulse-like acceleration waveform is input and the automobile body is elastically deformed, the vibration outside the control that occurs in the table 3 with the slide mechanism due to the influence of the vibration generated by restoring the elastic deformation It corresponds to the acting force in the course deviation direction in the test, and it is considered that the input energy input to the vibration device 5 to suppress the vibration outside the control of the table 3 with the slide mechanism corresponds to the additional steering operation in the running test.

  Here, the lower the rigidity of the automobile body, the larger the elastic deformation due to the input of pulse-like acceleration. Therefore, vibration outside the control of the table 3 with the slide mechanism due to the influence of vibration generated by restoring the elastic deformation. And the amount of energy input to the vibration device 5 to suppress vibrations outside the control increases. Therefore, it is possible to evaluate the dynamic rigidity, which is a characteristic of the automobile body related to the steering stability of an actual vehicle, by using the amount of energy input to suppress vibration outside the control as an evaluation index. Become.

  A specific experiment for confirming the function and effect of the method for testing the dynamic rigidity of an automobile body according to the present invention was performed, and this will be described below.

  In this embodiment, the dynamic stiffness test apparatus 1 shown in FIG. 1 is used, and the electromotive vibration device 13 is used as the vibration device 5 to move in the vehicle body width direction of the automobile body 21 and is input to drive control of the table 3 with the slide mechanism. The dynamic rigidity of the automobile body 21 was evaluated based on the input power amount.

  The car body 21 subjected to the dynamic rigidity test of this example was a car body skeleton of a commercially available small car (no doors / hood / fender, bumper reinforcement, windshield mounted, mass 240 kg). The total mass of the vibration table 7 including the fixing jig for fixing the automobile body 21 and the movable portion 11 of the electrodynamic vibration device 13 was 320 kg.

In the dynamic stiffness test, the target acceleration pattern was a single pulse wave with a half-sine shape with a maximum acceleration of 6.0 m / s ² and an action time of 50 ms.
Here, as the vibration device 5, the electrodynamic vibration device 13 (see FIG. 4) is used, and an input power pattern for driving the electrodynamic vibration device 13 so as to obtain a target acceleration pattern fixes the vehicle body 21. The acceleration frequency response behavior when the table 3 with the slide mechanism was driven was determined in advance.

  Further, as shown in FIG. 8, the same rigidity test was performed when two types of bolt-on type stiffening parts A and / or stiffening parts B were mounted on the rear side of the automobile body 21. Even when these stiffening parts are mounted and the state of the vehicle body 21 is changed, the input power pattern determined only by the vehicle body 21 is input to the electrodynamic vibration device 13 without being changed and tested. . The stiffening part A and the stiffening part B used in the present embodiment stiffen the rear side of the automobile body 21, and it has been demonstrated that the steering stability is improved in a sensory evaluation by a running test of an actual vehicle. It is a thing.

FIG. 9 shows measurement results of acceleration and displacement of the table 3 with the slide mechanism and a target acceleration pattern when the vehicle body 21 to which neither the stiffening component A nor the stiffening component B is mounted is used.
After 1.0 second has elapsed from the start of measurement, power is supplied to the electrodynamic vibration device 13 to start preliminary acceleration of the table 3 with the slide mechanism. Acceleration (maximum acceleration 6.0m / s ² ) is occurring. After the pulse-like acceleration is input, the vibration of the table 3 with the slide mechanism is rapidly attenuated and converged in about 0.5 seconds (1.5 seconds to 2.0 seconds). Here, although the acceleration waveform of the table 3 with the slide mechanism is substantially in the opposite phase to the input power pattern, the table 3 with the slide mechanism is subjected to vibration outside the control due to the influence of the vibration of the automobile body 21, and the acceleration waveform is disturbed. You can see that

  FIG. 10 shows the measurement result of the input power supplied to the electrodynamic vibration device 13. Electric power was turned on for preliminary acceleration 1.0 seconds after the start of measurement, and the electric power reached its peak 1.5 seconds later. Then, power was turned on to brake the table 3 with the slide mechanism until about 2.0 seconds, and vibration occurred. Is suppressed.

  Next, the same test is carried out by mounting a stiffening part on the car body 21, and the amount of power input to the electrodynamic vibration device 13 is measured for 1.0 seconds centering on 1.5 seconds at which acceleration reaches a peak. did.

In FIG. 11, the input power amount in the vehicle body 21 to which the stiffening part is applied is normalized based on the reference input power amount obtained by using the vehicle body 21 to which the stiffening part is not applied as the reference vehicle body. The result of the ratio is shown.
In FIG. 11, the reference is a standard automobile body that is not equipped with either the stiffening part A or the stiffening part B, the stiffening A is the stiffening part A, and the stiffening A + B is the stiffening part. This is a case where both the rigid part A and the stiffening part B are mounted.

  From FIG. 11, it can be seen that the input power amount decreases in the order of reference, stiffening A, and stiffening A + B. This is considered to be because the amount of input electric power that was input in order to suppress the vibration outside the control that occurs in the table 3 with the slide mechanism by applying the stiffening component decreased.

The two types of stiffening parts A and B used in the present embodiment have been verified for the effect on steering stability in an actual vehicle running test. The steering stability is determined by stiffening part A and stiffening part B. Only the stiffening part A was highly evaluated in the order of no stiffening part. Therefore, the above evaluation result showed a correlation with the result of the input power amount obtained in this example.
As described above, it has been proved that by evaluating the dynamic stiffness of the automobile body by the dynamic stiffness test method according to the present invention, the performance related to the steering stability during running of the actual vehicle can be evaluated by the laboratory test.

DESCRIPTION OF SYMBOLS 1 Dynamic rigidity test apparatus 3 Table with slide mechanism 5 Vibration apparatus 7 Vibration table 9 Linear guide 11 Movable part 13 Electrodynamic vibration apparatus 21 Automobile body

Claims (6)

A table with a slide mechanism capable of fixing an automobile body, a vibration device capable of vibrating the table with a slide mechanism in a horizontal one-axis direction with a predetermined acceleration pattern and suppressing vibration outside the control of the table with the slide mechanism; A vehicle body dynamic stiffness test method using
A vibration step of vibrating the table with the slide mechanism to which the vehicle body is fixed with a predetermined acceleration pattern, and then braking by suppressing vibration outside the control of the table with the slide mechanism, which is caused by the vibration of the vehicle body. A braking step for measuring, an input energy amount measuring step for measuring an input energy amount input to drive the vibration device within a predetermined section between the vibration step and the braking step, and a measurement by the input energy amount measuring step And a dynamic rigidity test method for an automobile body, comprising: an evaluation step for evaluating the dynamic rigidity of the automobile body based on the amount of input energy.   The dynamic rigidity test method for an automobile body according to claim 1, wherein the input energy amount measuring step measures an input energy amount input to drive the vibration device in the braking step.   The vibration device is an electrodynamic vibration device, and the input energy amount measurement step measures an input electric energy input to drive the electrodynamic vibration device as the input energy amount. The dynamic rigidity test method for an automobile body according to claim 1 or 2.   The vibration device is an electrodynamic vibration device, and the input energy amount measuring step includes a time response curve of a signal voltage or a signal current for controlling input power to be input to drive the electrodynamic vibration device. 3. The dynamic rigidity test method for an automobile body according to claim 1, wherein an integrated value is measured as the input energy amount. It has a reference input energy amount acquisition step of measuring a reference input energy amount by measuring an input energy amount measured for a standard automobile body,
5. The method for testing a dynamic rigidity of an automobile body according to claim 1, wherein the evaluation step performs evaluation based on a relative ratio between the reference input energy amount and the input energy amount.   The evaluation step normalizes the input energy amount input in the braking step on the basis of the input energy amount input from the start of the vibration step to the end of the braking step. The dynamic rigidity test method for an automobile body according to claim 5.