JP6575556B2 - Dynamic rigidity test method for automobile body - Google Patents

Description

  The present invention relates to a dynamic rigidity test method for an automobile body, and more particularly, to a dynamic rigidity test method for an automobile body that performs a dynamic rigidity test by applying a load in the vehicle body 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, an evaluation is performed by a torsional rigidity test in which an actuator is connected to each part, the left and right actuators are moved in opposite phases, the entire vehicle 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 ride comfort evaluation based on the feeling of left and right shaking in the driving test.

  Patent Document 3 uses a vehicle having a torsion spring means having one end fixed at the boarding position of an occupant and having a torsional rigidity in a direction centered on a specific axis. Disclosed is a technique that collects information directly related to the controllability / stability of the vehicle by detecting the phase lag between the rotation and the steering angle of the vehicle to quantify the feeling of controllability / stability felt by the occupant Has been.

JP 2006-292737 A Japanese Patent Laying-Open No. 2015-161588 JP 2003-42909 A

  However, in the conventional torsional rigidity test as in the technique disclosed in Patent Document 1 or Patent Document 2, the static rigidity value of the automobile body as a structure can be obtained. Correlation with sensory evaluation items during running of an actual vehicle such as performance and ride comfort is weak, and differences due to measurement sites are not taken into consideration.

  Further, according to the technology disclosed in Patent Document 3, the maneuverability and stability obtained by quantifying the human sense are appropriately detected by detecting the phase delay between the human sense and the vehicle behavior with respect to the driving operation of the vehicle. It is said that it can be evaluated. However, this technique performs a running test of an actual vehicle having tires and suspensions, and does not evaluate the rigidity of the automobile body itself.

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

  In addition, if it becomes possible to evaluate the dynamic rigidity of the car body related to the sensory evaluation value without performing a running test, the performance criteria and targets required for the car body will be clarified, and the body frame design stage Even so, it becomes easy to build vehicle performance. However, until now, no method has been proposed for testing the dynamic rigidity of an automobile body, which has a correlation with sensory evaluation during actual vehicle travel.

  The present invention has been made to solve the above-described problems, and provides a dynamic stiffness test method for an automobile body that obtains a dynamic stiffness index of the automobile body that has a high correlation with sensory evaluation by a running test of an actual vehicle. For the purpose.

  In order to obtain an index close to sensory evaluation values such as vehicle handling stability and ride comfort by a lab-scale stiffness test with the vehicle body as the test target, at least the dynamic deformation behavior of the vehicle body against changes in load It is important to measure As a rigidity test for measuring the dynamic deformation behavior of an automobile body, for example, a cyclic torsional deformation is given to an automobile body by continuously changing a load load in a conventional torsional rigidity test. A method of measuring the change and deformation behavior of each part of the car body can be considered. In such a torsional rigidity test, the deformation behavior when a load is input in the vertical direction of the vehicle due to a step on the road surface via a tire and a suspension is useful as test data on a laboratory scale.

  On the other hand, steering stability among vehicle performances is considered to have a strong correlation with vehicle response behavior when cornering or changing lanes. In such a case, unsteady operation due to a load acting in the vehicle body width direction is considered. It depends greatly on the transient (dynamic) deformation behavior. In particular, from the viewpoint of stability when changing lanes, vibration damping behavior in the process of restoring deformation of the automobile body after the load acting on the automobile body disappears is important. However, in the above-described torsional rigidity test, the deformation behavior of the automobile body due to the load acting in the vehicle body width direction cannot be obtained.

  Therefore, the inventors applied vibration to the vehicle body using a vibration device to apply a load in the vehicle body width direction, measured vibration damping behavior due to restoration of vehicle body deformation generated in the vehicle body by the load, and We examined a method to obtain a numerical index instead of sensory evaluation such as maneuvering stability without evaluating a real vehicle by evaluating dynamic rigidity.

  Specifically, the automobile body to be evaluated is fixed to a table with a slide mechanism that can move (accelerate, constant speed, and decelerate) in one horizontal axis, and after the table with the slide mechanism is accelerated, A test was conducted to directly measure the vibration damping behavior of the automobile body by applying a load in the vehicle body width direction of the automobile body by the vibration device controlled to brake.

  However, if the weight ratio to the table with the slide mechanism is large like the car body, the center of gravity position of the car body is high from the position of the table with the slide mechanism and the moment arm is long, in the process of sudden braking after accelerating the car body, Due to the vibration of the car body, out-of-control vibration occurred on the table with the slide mechanism.

  And when such out-of-control vibration occurs, the vibration of the table with the slide mechanism by the vibration device driven to suppress this interferes with the vibration attenuation of the car body, making it difficult to separate them. It has become difficult to evaluate dynamic stiffness based on the measurement results of vibration damping behavior of automobile bodies.

Therefore, the inventors examined a means for solving the above problem. As a result, the input energy pattern (change in input energy over time) input to the vibration device for accelerating and braking the table with the slide mechanism to which the automobile body is fixed is the same even when testing different automobile bodies. As a result, we came up with a comparison of vibration damping behavior.
The present invention has been made based on the above studies, and specifically comprises 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 the table with a slide mechanism is vibrated and accelerated in a horizontal axis direction with a predetermined acceleration pattern. And a vibration device to be braked thereafter, wherein the reference vehicle body is fixed to the table with the slide mechanism, the table with the slide mechanism is vibrated and braked with a predetermined acceleration pattern, and the vibration and the brake are caused. A reference input energy pattern acquisition step for acquiring a reference input energy pattern to be input to the vibration device, and a test body to be tested on which an accelerometer is installed is fixed to the table with the slide mechanism, and the reference device is fixed to the vibration device. Exciting and braking process in which an input energy pattern is input to vibrate and brake the table with the slide mechanism The vibration attenuation behavior of measuring the acceleration of the test vehicle body to which a load is applied in the vehicle width direction in the excitation and braking process by the accelerometer and obtaining the vibration attenuation behavior of the test vehicle body based on the measured acceleration An acquisition step and an evaluation step for evaluating the dynamic rigidity of the test vehicle body based on the acquired vibration damping behavior are provided.

(2) In the device described in (1) above, in the reference input energy pattern acquisition step, an accelerometer is installed in the reference vehicle body, the reference input energy pattern is acquired, and the acceleration of the reference vehicle body is determined by the accelerometer. The vibration damping behavior of the reference vehicle body is acquired based on the measured acceleration, and the evaluation step evaluates the dynamic rigidity of the test vehicle body based on the vibration damping behavior of the reference vehicle body. It is a feature.

(3) In the device described in (1) or (2) above, the vibration device is an electrodynamic vibration device, and the reference input energy pattern acquisition step uses the electrodynamic vibration as a reference input energy pattern. A reference input power pattern input to the apparatus is acquired, and the excitation and braking steps input the reference input power pattern to the electrodynamic vibration device.

(4) In the device according to any one of (1) to (3), the mass of the automobile body has a ratio of 1 to the total mass of the vibration table of the table with the slide mechanism and the movable unit of the vibration device. It is characterized by the following.

(5) In the device according to any one of (1) to (4), the evaluation step gives a pulse-like acceleration of the table with the slide mechanism to the time response curve of the absolute value of the measured acceleration. Time integration is performed from the time point until the vibration damping behavior of the acceleration converges, and evaluation is performed using the time integrated value.

(6) In the device according to any one of (1) to (4), the evaluation step calculates a time response curve of the absolute value of the measured acceleration from the start of excitation of the table with the slide mechanism. It is characterized in that time integration is performed until the vibration damping behavior of the lens converges, and evaluation is performed using the time integrated value.

(7) In the device according to any one of (1) to (6), the accelerometer is installed on a skeleton part of the automobile body.

(8) In the device described in (7) above, the accelerometer is installed in a skeleton part of a roof portion of the automobile body.

  The present invention uses a table with a slide mechanism that can fix an automobile body, and a vibration device that vibrates and accelerates the table with a slide mechanism in a horizontal axis direction with a predetermined acceleration pattern and then brakes the table. The reference vehicle body is fixed to the table with the slide mechanism, the table with the slide mechanism is vibrated and braked with a predetermined acceleration pattern, and the reference input energy pattern to be input to the vibration device for the vibration and braking is provided. A reference input energy pattern acquisition step for acquiring the test body, and a test vehicle body to be tested with an accelerometer installed thereon is fixed to the table with the slide mechanism, the reference input energy pattern is input to the vibration device, and the table with the slide mechanism Excitation and braking process for exciting and braking the vehicle, and the vehicle in the excitation and braking process A vibration damping behavior acquisition step of measuring an acceleration of the test vehicle body to which a load is applied in the width direction with the accelerometer, and acquiring a vibration attenuation behavior of the test vehicle body based on the measured acceleration, and the acquired vibration attenuation An evaluation process for evaluating the dynamic rigidity of the test vehicle body based on the behavior, thereby measuring the vibration damping behavior of the vehicle body when a load is applied in the vehicle body width direction of the vehicle body. Therefore, it is possible to obtain a dynamic stiffness index having a high correlation with the sensory evaluation related to the unsteady steering stability of the actual vehicle without performing a running test of the actual vehicle.

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. It is a figure explaining the electrodynamic vibration apparatus used as a vibration apparatus in the dynamic rigidity test apparatus of the motor vehicle body used by 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. 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 figure which shows the state which mounted | wore the test vehicle body with the stiffening component. In an Example, it is a figure which shows the time integral value of the absolute value of the acceleration of the vehicle body width direction measured with the accelerometer installed in the side sill inner about the test vehicle body equipped with the stiffening part. In an Example, it is a figure which shows the result of the vibration amount ratio calculated | required using the acceleration measured with the accelerometer with which the side sill inner and the front header were mounted | worn.

  The vehicle body dynamic stiffness test method according to the embodiment of the present invention uses a vehicle body dynamic stiffness test apparatus 1 (hereinafter simply referred to as “dynamic stiffness test apparatus 1”) as shown in FIG. Is what you do. First, the vehicle body 21 and the dynamic stiffness test apparatus 1 that are the subject of the present embodiment will be described with reference to FIGS.

<Auto body>
The automobile body 21 is a white body that does not include chassis parts, suspension parts, drive parts, interior parts, and the like, and has a vehicle body floor part and a suspension mount part for fastening a suspension.
The vehicle body 21 according to the present invention is intended for a reference vehicle body 21a as a reference of input energy to be input to drive the vibration device 5, and a test vehicle body 21b as a test object of dynamic rigidity. The reference vehicle body 21a may be used as a reference when evaluating the dynamic rigidity of the test vehicle body 21b.

<Dynamic stiffness testing device>
As shown in FIG. 2, the dynamic stiffness test apparatus 1 includes a table 3 with a slide mechanism that can fix an automobile body 21, and a table 3 with a slide mechanism that is vibrated and accelerated in a single horizontal axis direction with a predetermined acceleration pattern. Then, the vibration device 5 for braking and the accelerometer 7 for measuring the acceleration generated in the automobile body 21 are provided.

The table 3 with a slide mechanism fixes the automobile body 21 and linearly moves in the vehicle body width direction of the automobile body 21. As shown in FIG. 2, the linear guide 11 installed in the vehicle body width direction of the automobile body 21. And a vibration table 9 installed on the linear guide 11 so as to be linearly movable.
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. But the part which fixes the motor vehicle body 21 should just be selected suitably according to the content and purpose which evaluate the characteristic of the motor vehicle body 21. FIG.

The vibration device 5 oscillates and accelerates the table 3 with a slide mechanism (vibration table 9) to which the automobile body 21 is fixed in a horizontal acceleration direction with a predetermined acceleration pattern, and then brakes the table 3. Are connected to the table 3 with the slide mechanism.
Then, the vibration device 5 is driven to vibrate and brake the table 3 with the slide mechanism with a predetermined acceleration pattern, thereby applying a load in the vehicle body width direction of the vehicle body 21 fixed to the table 3 with the slide mechanism. . Thereby, in the automobile body 21, elastic deformation occurs due to the load acting in the vehicle body width direction.

  The vibration device 5 generates and acquires a reference input energy pattern to be input to the vibration device 5 in order to vibrate and brake the table 3 with a slide mechanism to which the reference vehicle body 21a is fixed with a predetermined acceleration pattern. The vibration device 5 is driven according to the reference input energy pattern, and the table 3 with a slide mechanism to which the test vehicle body 21b to be tested is fixed is vibrated and then braked.

As the vibration device 5, an electrodynamic vibration device 15 shown in FIG. 3 can be used.
The electrodynamic vibration device 15 drives the drive coil in the operation direction shown in FIG. 3 by a force generated by applying a predetermined current to the drive coil in a magnetic field generated by the excitation coil. Then, by connecting the movable portion 13 having the drive coil of the electrodynamic vibration device 15 to the table 3 with the slide mechanism, the table 3 with the slide mechanism is vibrated and braked as the electrodynamic vibration device 15 is driven. be able to.

  The electrodynamic vibration device 15 includes a control device that drives and controls the electrodynamic vibration device 15 as a function for driving the table 3 with the slide mechanism to which the reference vehicle body 21a is fixed with a target acceleration pattern. Yes. 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 15 to vibrate with an acceleration pattern can be used. Furthermore, it is preferable that the control device also has a function of outputting actual data of input power patterns input to drive the electrodynamic vibration device 15.

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

<Dynamic rigidity test method for automobile bodies>
The dynamic stiffness test method according to the present embodiment (hereinafter simply referred to as “dynamic stiffness test method”) uses the dynamic stiffness test apparatus 1 shown in FIG. 2, and as shown in FIG. A reference input energy pattern acquisition step S1, a vibration and braking step S3, a vibration damping behavior acquisition step S5, and an evaluation step S7.
Hereinafter, each of the above steps will be described together with the operation of the dynamic stiffness test apparatus 1.

<Standard input energy pattern acquisition process>
In the reference input energy pattern acquisition step S1, as shown in FIG. 2, the reference vehicle body 21a is fixed to the table 3 with the slide mechanism, the table 3 with the slide mechanism is vibrated and braked , and the vibration and braking are performed with a predetermined acceleration pattern. This is a step of acquiring a reference input energy pattern to be input to the vibration device 5 in order to perform the operation.
The reference input energy pattern input to the vibration device 5 can be obtained by the procedure shown in FIG. Hereinafter, a procedure for obtaining a reference input power pattern as a reference input energy pattern input to the electrodynamic vibration device 15 when the electrodynamic vibration device 15 is used as the vibration device 5 will be described.

  First, the transfer function (response function for each frequency) of the table 3 with the slide mechanism to which the reference vehicle body 21a is fixed is measured (S11). Based on the measured transfer function, the electrodynamic vibration device 15 is moved with a predetermined acceleration pattern. A control constant for driving is determined (S13).

Next, using the determined control constant, a control program for driving and controlling the electrodynamic vibration device 15 to drive with an acceleration pattern is generated (S15).
Then, the control program determined as described above is output, and a reference input power pattern required for driving the table 3 with the slide mechanism to which the reference vehicle body 21a is fixed is acquired (S17).

<Excitation and braking process>
In the vibration and braking step S3, as shown in FIG. 2, the test vehicle body 21b on which the accelerometer 7 is installed is fixed to the table 3 with the slide mechanism, and the reference input acquired in the reference input energy pattern acquisition step S1. In this step, the energy pattern is input to the vibration device 5 to vibrate and brake the table 3 with the slide mechanism.
In the vibration and braking step S3, a force is applied in the vehicle body width direction of the test vehicle body 21b by transmitting force to the test vehicle body 21b via the front suspension portion and the vehicle body floor portion fixed to the table 3 with the slide mechanism. As a result, elastic deformation occurs.

  Regarding the position where the accelerometer 7 is installed on the test vehicle body 21b, for example, a roof panel or the like has a small contribution to the vehicle body rigidity and has a large vibration component related to the deformation of the roof panel itself. , Side sill, roof side rail, front header, etc.). Furthermore, when the test vehicle body 21b is an elastic body and the lower part thereof is fixed to the table 3 with the slide mechanism and is vibrated and braked, the upper skeleton of the test vehicle body 21b vibrates more greatly, as shown in FIG. It is more preferable to install the accelerometer 7 on the frame parts (roof side rail, front header, etc.) of the roof portion 17 of the test vehicle body 21b.

<Vibration damping behavior acquisition process>
In the vibration damping behavior acquisition step S5, the acceleration of the test vehicle body 21b applied with a load in the vehicle body width direction in the vibration and braking step S3 is measured by the accelerometer 7, and the vibration attenuation of the test vehicle body 21b is measured based on the measured acceleration. This is a process of acquiring behavior.
In the vibration damping behavior acquisition step S5, for example, a time response curve of the acceleration of the test vehicle body 21b from the start of the vibration of the table 3 with the slide mechanism in the vibration and braking step S3 to the end of the braking is acquired as the vibration damping behavior. can do. FIG. 5 shows an example of the time response curve of the acceleration of the test vehicle body 21b. The acceleration (actual result) in FIG. 5 is a time response curve of the acceleration measured by the accelerometer 7 installed in the test vehicle body 21b.
In the acquisition of the vibration damping behavior, the vibration start of the table 3 with the slide mechanism is the time when the pulsed acceleration is applied in the case of applying the pulsed acceleration as shown in FIG. it can. Further, in the acquisition of the vibration damping behavior, the end of the braking of the table 3 with the slide mechanism can be the time when the vibration damping of the acceleration of the test vehicle body 21b has sufficiently converged.

<Evaluation process>
The evaluation step S7 is a step of evaluating the dynamic rigidity of the test vehicle body 21b based on the vibration damping behavior acquired in the vibration damping behavior acquisition step S5.
First, the time response curve of the absolute value of the acceleration acquired in the vibration damping behavior acquisition step S5 is time-integrated in a section from the start of vibration to the end of braking of the table 3 with the slide mechanism. Then, the value obtained by time integration of the time response curve of the absolute value of acceleration is regarded as the vibration amount of the test vehicle body 21b, and the dynamic rigidity of the test vehicle body 21b can be evaluated based on the vibration amount.

  Here, in the case of applying a pulse-like acceleration as shown in FIG. 5, the vibration start of the table 3 with a slide mechanism can be the time when the pulse-like acceleration is applied. Further, in the acquisition of the vibration damping behavior, the end of the braking of the table 3 with the slide mechanism can be the time when the vibration damping behavior of the acceleration of the test vehicle body 21b has sufficiently converged.

  The vibration amount thus determined has a high correlation with the vibration damping behavior due to the elastic recovery of the deformation of the vehicle body. When the vibration amount value is large, it is evaluated that the dynamic rigidity of the test vehicle body 21b is low. When the value of is small, it can be evaluated that the dynamic rigidity of the test vehicle body 21b is high.

  In addition, it is good also as the time of giving the acceleration from the preliminary | backup acceleration stage shown in FIG. 5 as a vibration start of the said table 3 with a slide mechanism.

  Further, in the reference input energy pattern acquisition step S1, the accelerometer 7 is installed in the reference vehicle body 21a, the reference input energy pattern is acquired, the acceleration of the reference vehicle body 21a is measured by the accelerometer 7, and based on the measured acceleration. Thus, the vibration damping behavior of the reference vehicle body 21a may be acquired, and the evaluation step S7 may evaluate the dynamic rigidity of the test vehicle body 21b based on the vibration damping behavior of the reference vehicle body 21a.

  In this case, in the evaluation step S7, the vibration amount is obtained by time integration of the time response curve of the vibration damping behavior acquired for the reference vehicle body 21a, and the vibration amount for the test vehicle body 21b is determined with reference to the vibration amount for the reference vehicle body 21a. The relative ratio can be determined. Thereby, for example, it is possible to evaluate the rigidity improvement effect by attaching a stiffening part to the automobile body 21 and the rigidity of different automobile bodies 21 on a certain standard.

  In addition, when the mass of the vehicle body 21 (the reference vehicle body 21a or the test vehicle body 21b) is larger than the total mass of the table 3 with the slide mechanism and the movable portion 13 of the vibration device 5, the vibration of the vehicle body 21 due to vibrations outside the control. The influence becomes large, and the table 3 with the slide mechanism may not be vibrated and braked with a predetermined acceleration pattern. Therefore, in the dynamic stiffness test method according to the present embodiment, the mass of the automobile body 21 is preferably set to 1 or less in the ratio of the total mass of the table 3 with the slide mechanism and the movable portion 13.

  Furthermore, in the above description, an example in which the electrodynamic vibration device 15 is used as the vibration device 5 is shown. However, the vibration device 5 can vibrate and brake the table 3 with the slide mechanism with a predetermined acceleration pattern. As long as it is not limited to the electrodynamic vibration device 15, 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 the hydraulic vibration device 5 is used, the actual function data of the control function of exciting with a predetermined acceleration pattern using the servo valve and the input energy pattern input to the drive of the vibration device 5 is used as the actual data of the hydraulic pressure and the servo valve. What is necessary is just to have the function to output time series data, such as opening and closing. In this case, the input energy pattern can be obtained from the control data for opening and closing the servo valve for controlling the predetermined acceleration pattern by the hydraulic vibration device 5.

  Further, when the motor-type vibration device 5 is used, for example, a control function for exciting with a predetermined acceleration pattern by a pulse motor and a time change of input power input to drive the pulse motor are output as performance data. Any function may be used. In this case, the input energy pattern can be acquired from the electric power input to drive the motor.

<Relationship with sensory evaluation by running test of actual vehicle>
The reason why a physical numerical index correlated with sensory evaluation such as steering stability and riding comfort can be obtained by the dynamic stiffness test method according to the present embodiment will be described.

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 test vehicle body 21 b is fixed to the table 3 with a slide mechanism at a position that can serve as an input point of force when the actual vehicle travels, such as a vehicle body floor portion and a suspension mount portion that are the lower portion of the vehicle body. Therefore, the table 3 with the slide mechanism can be considered to simulate a chassis that transmits changes in the direction of movement and speed of the vehicle to the vehicle body skeleton when the vehicle is traveling.

  And the driving test is to run on the determined driving route and sensory evaluate the handling stability and ride comfort etc. When the purpose is to evaluate the influence of the body on the same platform, the input transmitted from the chassis to the body is It is assumed that they are almost the same, and the difference in response behavior and characteristics of the body when receiving the same input 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 traveling conditions, it is determined that the steering stability is better as the vehicle has fewer additional steering operations.

In the dynamic stiffness test method according to the present embodiment, an additional steering operation in such a running test is an input energy pattern that is input to the vibration device 5 in order to suppress vibration outside the control of the table 3 with the slide mechanism. It is thought that it corresponds to.
That is, after the target pulse-like acceleration waveform is input and the test vehicle body 21b is elastically deformed, vibration outside the control that occurs in the table 3 with the slide mechanism due to the influence of vibration generated by restoring the elastic deformation, It corresponds to the acting force in the course departure direction in the running test, and the driving of the vibration device 5 for suppressing the vibration outside the control of the table 3 with the slide mechanism is considered to correspond to the steering of the vehicle body by the additional steering operation in the running test. .

  Here, the lower the rigidity of the test vehicle body 21b, the larger the elastic deformation due to the input of pulse-like acceleration. Therefore, the table 3 with the slide mechanism is out of control due to the influence of vibration generated by restoring the elastic deformation. The vibration also increases, the input energy input to the vibration device 5 to suppress the vibration outside the control increases, and the input energy pattern changes. Therefore, by measuring the vibration damping behavior of the test vehicle body 21b when the input energy pattern to be input to the vibration device 5 is the same, the sensory evaluation of the steering stability obtained under the same driving condition in the driving test and the correlation A numerical index of certain dynamic stiffness can be obtained.

  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 vibration of the automobile body 21 when the dynamic stiffness test apparatus 1 shown in FIG. 2 is used and the vibration apparatus 5 is vibrated and braked in the vehicle body width direction of the automobile body 21 by the electrodynamic vibration device 15 is used. The damping behavior was acquired, and the effect of dynamic rigidity improvement when a stiffening part was mounted on the car body 21 was examined.

The car body 21 subjected to the dynamic rigidity test is a car body skeleton of a commercially available small car (no doors / hood / fender, bumper reinforcement, windshield mounted, mass 240 kg), and a roof part 17 that is a skeleton part of the car body 21. Accelerometer 7 is installed on each of the roof side rail and the side sill inner of the side sill portion 19 (see FIG. 2), and the acceleration time is taken as the vibration attenuation behavior of the automobile body 21 when the table 3 with the slide mechanism is vibrated and braked. Response curves were measured.
The total mass of the vibration table 9 including the fixing jig for fixing the vehicle body 21 and the movable portion 13 of the electrodynamic vibration device 15 is 320 kg. The mass of the vehicle body 21 is the vibration table of the table 3 with the slide mechanism. 9 and the total mass of the movable part 13 of the electrodynamic vibration device 15 were 240 kg / 320 kg = 0.75.

In this embodiment, the reference input power to be input to the electrodynamic vibration device 15 from the acceleration frequency response behavior when the reference vehicle body 21a is fixed to the table 3 with the slide mechanism and driven so as to have a target acceleration pattern. I got the pattern. Here, the acceleration pattern targeted for excitation and braking of the reference vehicle body 21a is a single pulse wave having a half-sine shape with a maximum acceleration of 6.0 m / s ² and an action time of 50 ms.

  FIG. 5 shows the time response curve of the acceleration of the reference vehicle body 21a when the reference vehicle body 21a is fixed to the table 3 with the slide mechanism and the vibration and braking are performed, the measurement result of the displacement of the table 3 with the slide mechanism, and the target. An acceleration pattern is shown.

After the elapse of 2.0 seconds from the start of measurement, power is supplied to the electrodynamic vibration device 15 to start the preliminary acceleration of the table 3 with the slide mechanism, and a target pulse-like shape is obtained during 0.05 seconds centering on 2.5 seconds. Acceleration (maximum acceleration 6.0m / s ² ) is occurring. After inputting the pulse-like acceleration, the vibration of the table 3 with the slide mechanism is rapidly attenuated and converged in about 0.5 seconds (2.5 seconds to 3.0 seconds). Here, although the acceleration waveform of the table 3 with the slide mechanism is substantially opposite in phase to the input power pattern that decreases in each cycle, the table 3 with the slide mechanism is subjected to vibration outside the control due to the influence of the vibration of the reference vehicle body 21a. It turns out that the disturbance which does not reduce for every period has arisen in the waveform.

  Next, a bolt-on type stiffening part was attached to the test vehicle body 21b shown in FIG. 6, and the electrodynamic vibration device 15 was driven with the reference input power pattern to measure the vibration damping behavior of the test vehicle body 21b. Here, as the stiffening parts to be mounted on the test vehicle body 21b, two types of stiffening parts A and B are used. When only the stiffening part A is mounted, the stiffening parts A and B Each of the cases where both were mounted was tested.

  In addition, the stiffening part A and the stiffening part B used in this example are improved in steering stability compared to an actual vehicle in which any of the stiffening parts are not mounted in the sensory evaluation by a running test of the actual vehicle. Compared with the case where only the stiffening part A is mounted, the result that the steering stability is further improved in the actual vehicle in which both are mounted has been demonstrated.

  FIG. 7 shows the time integral value of the absolute value of acceleration in the vehicle body width direction measured by the accelerometer 7 installed on the side sill inner in the test vehicle body 21b in which only the stiffening part A is mounted. Measurement is started at time 1.5 seconds, specified pulse vibration is input at time 2.0 seconds 0.5 seconds later, vibration is generated in the test vehicle body 21b, and target pulse-like acceleration is generated in 2.5 seconds. It can be seen that the decay and convergence suddenly took about 0.5 seconds.

  From the result of FIG. 7, the absolute value of the acceleration measured for 0.5 seconds from the input of the pulsed acceleration to the vibration convergence is integrated over time, and the integrated value of the time integrated value is defined as the vibration amount. The change of vibration amount by wearing was compared.

  FIG. 8 shows the vibration obtained from the acceleration measured using the accelerometer 7 attached to the side sill inner and the roof side rail for the reference vehicle body 21a without the stiffening component and the test vehicle body 21b with the stiffening component attached. The quantity results are shown. In FIG. 8, the “reference” shown on the horizontal axis is the reference vehicle body 21 a, “stiffening A” is the test vehicle body 21 b with the stiffening part A attached, and “stiffening A + B” is the stiffening part A and the stiffening part B. The test vehicle body 21b is mounted, and the “vibration amount ratio” on the vertical axis is standardized by the vibration amount of the reference vehicle body 21a to which no stiffening component is mounted.

  As shown in FIG. 8, since the vibration amount ratio decreases in the order of standard, stiffening A, and stiffening A + B, the dynamic rigidity is improved by attaching the stiffening parts. By mounting the rigid part B, it can be evaluated that the dynamic rigidity is further improved. As described above, in the running test of an actual vehicle, the steering stability is improved in the order of mounting the stiffening part, mounting the stiffening part A, and mounting both the stiffening part A and the stiffening part B. In addition, it can be seen that the evaluation result of the dynamic rigidity of the test vehicle body 21b obtained in the present example is highly correlated with the result of the steering stability in the running test of the actual vehicle.

  Further, regarding the difference in the position where the accelerometer 7 is installed, in both the results of stiffening A and stiffening A + B in FIG. 8, the acceleration measured by the accelerometer 7 installed on the roof side rail is used compared to the side sill inner. The vibration amount ratio is smaller. From this, it was suggested that the roof side rail at the upper part of the test vehicle body 21b vibrates more greatly than the side sill inner at the lower part.

  As described above, according to the dynamic rigidity test method for an automobile body according to the present invention, the dynamic rigidity highly correlated with the steering stability is evaluated by the laboratory test using the automobile body without performing the running test of the actual vehicle. It was shown that it can be done.

DESCRIPTION OF SYMBOLS 1 Dynamic rigidity test apparatus 3 Table with slide mechanism 5 Vibration apparatus 7 Accelerometer 9 Vibration table 11 Linear guide 13 Movable part 15 Electrodynamic vibration apparatus 17 Roof part 19 Side sill part 21 Automobile body 21a Reference body 21b Test body

Claims (7)

A vehicle body dynamic stiffness test using a table with a slide mechanism capable of fixing an automobile body, and a vibration device that vibrates and accelerates the table with a slide mechanism in a horizontal axis direction with a predetermined acceleration pattern and then brakes the table. A method,
The reference vehicle body is fixed to the slide mechanism-Table to a load in the vehicle width direction is acted, in order to vibration and damping table with the slide mechanism at a predetermined acceleration pattern, a reference to be introduced to the vibration device A reference input energy pattern acquisition step of acquiring an input energy pattern , measuring an acceleration of the reference vehicle body when the acquired reference energy pattern is input, and acquiring a vibration damping behavior of the reference vehicle body based on the measured acceleration ; ,
A test vehicle with an accelerometer as a test object is fixed to the table with the slide mechanism so that a load is applied in the vehicle body width direction, and the reference input energy pattern is input to the vibration device, thereby the table with the slide mechanism. An excitation and braking process for exciting and braking
Acquire vibration damping behavior of measuring the acceleration of the test vehicle body, to which a load is applied in the vehicle width direction in the excitation and braking process, by the accelerometer, and acquiring the vibration attenuation behavior of the test vehicle body based on the measured acceleration Process,
An evaluation step of evaluating a dynamic rigidity of the test vehicle based on the vibration attenuation behavior of the reference vehicle based on the acquired vibration attenuation behavior of the test vehicle. Stiffness test method. The vibration device is an electrodynamic vibration device, and the reference input energy pattern acquisition step acquires a reference input power pattern to be input to the electrodynamic vibration device as a reference input energy pattern, and the excitation and braking step, the dynamic stiffness test method for automobile body according to claim 1, characterized in that to put the reference input power pattern on the electrodynamic vibrating device. The automobile body mass is moving the automobile body according to claim 1 or 2 ratio of the total mass of the movable portion of the vibrating table and the vibrating device of the sliding mechanism-Table is characterized in that 1 or less Stiffness test method. The evaluation step time-integrates the time response curve of the absolute value of the measured acceleration in a section from when the pulse-like acceleration of the table with the slide mechanism is applied until the vibration damping behavior of the acceleration converges, The dynamic rigidity test method for an automobile body according to any one of claims 1 to 3 , wherein the evaluation is performed using a value obtained by time integration. In the evaluation step, the time response curve of the absolute value of the measured acceleration is integrated over time in the interval from the start of excitation of the table with the slide mechanism until the vibration damping behavior of the acceleration converges, and the time integrated value The dynamic rigidity test method for an automobile body according to any one of claims 1 to 3 , wherein the dynamic rigidity test method is used. The accelerometer dynamic stiffness test method for automobile body according to any one of claims 1乃optimum 5, characterized in that installed in the skeleton parts of the automobile body. The method according to claim 6 , wherein the accelerometer is installed on a skeleton part of a roof portion of the automobile body.