JP2020046180A - Simple test method for snowfall strength of automobile - Google Patents

Abstract

To provide a test method capable of easily and accurately evaluating a snowfall strength evaluation test of an automobile.SOLUTION: In a simple test method of snowfall strength for an automobile, a roof model 1 of the same size as a roof panel to be evaluated or a shape reduced from the roof panel is prepared, a uniform load is applied to a surface of the roof model 1 from above while an outer periphery of the roof model 1 is fixed to a base 2, and the amount of deformation of the roof model 1 due to the load is measured.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a simple test method for evaluating snow intensity of a vehicle.

Automotive panel components include an outer panel component called an outer and an inner panel component such as a floor and a dash lower. This automotive panel component is a component group having a large projected area. For this reason, the amount of weight reduction of the automotive panel component due to the reduction of the plate thickness is much larger than that of other skeletal components. Among them, since the roof panel component has a large projected area, the effect of weight reduction by thinning is particularly great.
The roof panel component is a component having a great effect of weight reduction particularly in a vehicle such as a van or a minivan. In addition, there is a tendency that lowering the center of gravity of the vehicle body is demanded from the viewpoint of excellent maneuverability and driving pleasure, so that the need for a lighter roof at the upper part of the vehicle is particularly high.

  On the other hand, one of the required performances of the roof is the snow intensity. When an automobile is traveling outdoors or parked and stopped outdoors, snow may accumulate on the roof panel and the load may cause the roof panel to be inverted. The snowfall intensity is a strength required to prevent the roof panel from being inverted due to the weight of the snowfall and causing the panel to return to its original state and cause permanent deformation. This snow intensity is a special performance required only for roof panels. The snowfall intensity is a name of intensity, but it can be considered as a kind of rigidity because it relates to inversion (buckling) of the panel.

  However, regardless of the season, a snowfall machine is required and a large space capable of maintaining a low temperature is required in order to carry out a test by actually applying snow to an automobile. It is also necessary to actually make a prototype for evaluation. Here, as a substitute for snow cover, a method of applying a hydraulic load, earth and sand, or the like can be considered to apply an evenly distributed load to the entire surface of the roof panel. However, with such a loading method, it is practically difficult to realize an evenly distributed load because the area of the roof panel is large.

  2. Description of the Related Art Conventionally, as a strength / rigidity test of a panel component for an automobile, there is a technique described in Patent Documents 1 and 2, for example. Patent Literature 1 describes a technique related to an evaluation test of tension rigidity in which a metal panel is pushed by an indenter. Further, Patent Literature 2 discloses a method of dent evaluation in a sharply changing portion of curvature (a portion such as a character line or a bead provided to an outer panel). However, these are all cases where a load is locally applied, and are related to evaluation of tensile rigidity and dent resistance when a person presses a panel with a finger or hand. Such an evaluation is not an evaluation in a test in which an evenly distributed load is applied to the entire surface of the panel, such as the snowfall strength, but a performance that is not regarded as important in a roof panel that is relatively hard to touch by humans.

  Further, as a test relating to the performance of the roof panel, there is a hail test disclosed in Patent Documents 3 and 4. Particularly in Europe and the United States, the occurrence of deformation of automobile panel parts (roof, hood, etc.) due to hail has become a problem. However, although the range of the evaluation target is the entire roof panel as in the case of the snowfall intensity, the load conditions simulate a state in which the hail individually hits the roof panel individually. For this reason, the hail test is also a test mode in which a load is locally applied.

  At present, the evaluation test of the snow intensity of the roof is performed in such a manner that one vehicle itself is prototyped, a weight is sequentially placed on the surface of the roof panel, and a load is sequentially applied. However, when a partial load is sequentially applied to the surface of the roof panel with a weight, in the process, the entire surface of the roof panel is not uniformly distributed but has a biased load distribution. . Therefore, in such a test, it is considered that the evaluation accuracy of the snowfall strength is insufficient.

Japanese Patent No. 5024152 Japanese Patent No. 5919782 JP 2010-97098 A JP 2011-75307 A

  The present invention has been made in view of the above points, and an object of the present invention is to provide a test method capable of easily and accurately evaluating the snowfall intensity of an automobile.

It is also conceivable to create a miniature model in which the actual vehicle to be evaluated is reduced and perform an evaluation test of the snowfall intensity. However, if a miniature car is simply made with a scale-down model that is a fraction of the actual car, it is necessary to manufacture dies for the number of parts, and the welding machine must be miniaturized. It is not realistic to carry out such man-hours and investment for each vehicle type development.
Therefore, the inventor has conceived of a method capable of qualitatively verifying whether or not there is an effect of the snowfall strength measure in consideration of a component structure, a design shape of a roof panel, and the like without faithfully reproducing a test on an actual vehicle. Then, the inventor interprets the upper part (upper body) of the vehicle body as a “base” for evaluation, manufactures the base (upper body) as a rigid body, and places a separately manufactured roof panel (roof outer panel) thereon. ) And put on a model for evaluation.

In other words, in order to solve the problem, a simple method for testing snow intensity of an automobile according to one embodiment of the present invention provides a roof model having the same size as the roof panel to be evaluated or a shape obtained by reducing the size of the roof panel. The gist of the present invention is to apply an evenly distributed load to the roof model surface from above while fixing the outer peripheral portion to the base, and measure the amount of deformation of the roof model due to the load.
The roof model is preferably a miniature shape in which the roof panel is reduced in consideration of the production of the model and the realization of uniformly distributed load.
Considering the realization of the uniformly distributed load, it is preferable to use a soft rubber sheet panel for the uniform distributed load.

According to one embodiment of the present invention, by using a simple model around the roof panel, it is possible to suppress the cost and the number of steps and to easily evaluate the snowfall intensity. As a result, the effect of countermeasures against snowfall can be easily verified, so that more effective component design is possible.
In particular, when a roof model with a miniaturized roof panel is adopted, the area for applying evenly distributed loads is reduced, making it easier to apply evenly distributed loads to the roof model, and reducing the work space used for testing. You can do it.

It is a figure showing an example of a roof model. It is a figure showing the example of a foundation. It is a figure showing the example of restriction of a foundation. It is a figure showing an example of a measure of preventing rattling of a roof model. It is a figure which shows the example which loaded the rubber sheet panel as a weight. It is a figure showing the relation between displacement and snow load.

Next, an embodiment of the present invention will be described with reference to the drawings.
The evaluation method of the present embodiment includes a roof model, a base for restraining the roof model, a displacement meter for measuring a displacement (amount of deformation) of the roof model in a thickness direction, and a weight for realizing an evenly distributed load. .
<Roof model>
The roof model 1 is a model that simulates a roof panel to be used in an actual vehicle to be evaluated, as shown in FIG.
The roof model 1 may be a model having the same size as the roof panel, but a miniature model obtained by reducing (reducing) the size of the roof panel is preferable.

In the following description, a case in which a miniature model with a reduced roof panel is used as the roof model 1 will be described as an example.
As for the reduced size, it is considered that the larger the scale is, the higher the evaluation accuracy is. However, considering the ease of evaluation, the smaller the scale is, the better. From such a viewpoint, the scale is set to, for example, 1/5 to 1/15 in plan view. Note that a large scale means that the degree of reduction is small.
In the following description, a case where 1/10 is adopted as the scale in plan view will be described as an example.

  Here, the roof model 1 is preferably made as thin as possible in accordance with the size reduction in order to reduce the size effect caused by the size reduction in plan view. However, if the roof model 1 is made of a resin having a low Young's modulus, for example, the rigidity of the joint cannot be secured, and a necessary test may not be performed. Therefore, as the material of the roof model 1, it is effective to use the same material (iron or aluminum metal) as the roof outer panel of the actual vehicle or a material having a similar Young's modulus.

However, even if the same material (iron or aluminum metal) as the roof outer panel of the actual vehicle is used, the smaller the scale, the smaller the thickness of the board, if the same scale as that in plan view is adopted, In some cases, it is too thin to secure rigidity and is not suitable for evaluation. In such a case, the scale of the plate thickness is set to be relatively larger than the scale in plan view, that is, the plate thickness is set to be relatively thicker.
Even if the scale of the plate thickness is set to be large, it is possible to accurately evaluate the snow intensity by setting the evaluation standard to the same plate thickness.

<Base>
The base is a component that fixes the outer periphery of the roof model 1 and restrains the roof model 1 without rattling. Since the roof panel and the upper body of the vehicle body are usually joined by welding, it is preferable to fix the outer periphery of the roof model 1 so that the base does not rattle.
As the base 2, for example, as shown in FIG. 2, an upper model having a shape in which an upper body, which is an upper portion of a vehicle body, is reduced to the same size as the roof model 1 is adopted. However, the material of the upper model need not be the same as the material of the upper body. The upper model may be made of resin.

The upper model may be produced by, for example, a three-dimensional printer or by press molding.
When a three-dimensional printer is used, an upper model can be manufactured with high accuracy. When manufacturing with a three-dimensional printer, for example, the upper model is made of resin.
Here, it is preferable that the joint between the base 2 and the roof model 1 has no rattling or the like. For this reason, the joint of the base 2 and the roof model 1 requires a shape with a predetermined or higher reproduction accuracy. Therefore, it is effective to manufacture the base 2 as a “block” using a three-dimensional printer. The material may be metal or resin, but in order to exhibit the function of the base 2, it is necessary to increase rigidity. In the case of a resin having a low Young's modulus, it is effective to improve the bending rigidity and the torsional rigidity by taking structural measures such as inserting a beam.

The base 2 composed of the upper model may be manufactured by press molding. Since the size is small, only a small mold needs to be manufactured, and there is no problem even if an inexpensive mold such as a ZAS mold is applied.
In addition, as shown in FIG. 3 and FIG. 4, mechanical constraints, tapes, adhesives, etc. are used for the constraint (joining) between the base 2 and the roof model 1 as shown in FIGS. You may. FIG. 3 is an example in which the restraint device 3 is arranged on the outer periphery of the base 2 to suppress deformation of the base 2. FIG. 4 shows an example in which the tape 5 is temporarily fixed.

<Displacement meter>
The displacement meter 4 is disposed below the roof model 1 and measures the displacement (deformation amount) of the roof model 1 in the thickness direction in a contact or non-contact manner. FIG. 3 illustrates a case where the displacement meter 4 is a contact displacement meter 4.
The displacement meter 4 may be a device for measuring a three-dimensional shape by an optical method with a grid or the like.
The measurement position of the displacement meter 4 is set to a portion where the displacement is relatively large by a simulation analysis such as CAE. Two or more displacement meters 4 may be set to measure displacements at a plurality of locations.

<Weight>
The weight of the present embodiment includes a plurality of rubber sheet panels having the same shape as the roof model 1 in plan view and having the same area as the roof model 1. Equal means that the rubber sheet panel can cover, for example, 80% or more, preferably 95% or more of the area of the roof model 1.
By laminating the rubber sheet panel 6 on the roof model 1 as shown in FIG. 5, it is possible to easily change the uniformly distributed load to be applied.
It is preferable that the rubber sheet panel 6 be deformed so as to conform to the surface shape of the roof model 1 and to apply a load as evenly distributed as possible. For example, as the rubber sheet panel 6, the material of the rubber sheet panel 6 may be a soft material, or the rubber sheet panel 6 having a small thickness may be used. In particular, in order to increase the degree of adhesion between the rubber sheet panel 6 and the surface shape of the roof model 1, it is preferable to employ a soft rubber material for at least the lowermost rubber sheet panel 6.
A plurality of such rubber sheet panels 6 are prepared and sequentially placed to change the applied load. Then, the current applied load is determined by the weight and the number of the laminated rubber sheet panels 6.

<Operation and others>
The outer periphery of the roof model 1 is fixed to the base 2 and restrained. Then, each time the rubber sheet panel 6 is laminated on the roof model 1, the displacement meter 4 measures the amount of downward displacement of the roof model 1 with the displacement meter 4.
Thereby, the relationship between the applied evenly distributed load and the displacement of the panel is obtained.
Then, for example, an evaluation criterion serving as a criterion for the relationship between the uniformly distributed load to be applied and the displacement of the panel is compared with the measured relationship, and the displacement with respect to the snow load becomes smaller than the base criterion. Whether or not the snow intensity has been improved is evaluated depending on whether or not the snowfall has increased.

The roof model 1 as the evaluation criterion is obtained using a model having the same scale and the same thickness as the roof model 1 to be evaluated. For example, a roof model 1 as an evaluation standard is manufactured from a roof panel of a current vehicle. The evaluation criteria may be determined by analysis such as CAE.
It should be noted that once the data of the evaluation criterion is determined, the degree of improvement in the snow intensity can be evaluated by comparison with the evaluation criterion.
According to this embodiment, a simple miniature snow test model is used.

  Conventionally, in order to verify the effect of snow intensity countermeasures, it was impossible to accurately evaluate snow intensity without producing a vehicle itself, but in this embodiment, the cost and man-hours were reduced, and the snow intensity was easily measured. Evaluation becomes possible. As a result, the effect of the countermeasure can be easily verified, so that more effective component design is possible. The reduction ratio from the actual vehicle is not particularly limited. However, when the base 2 is manufactured by a three-dimensional printer, the size of the roof model 1 is preferably 500 mm × 500 mm or less because it depends on the restriction on the size of the base 2 to be manufactured.

  Further, in the present embodiment, it is possible to qualitatively verify whether or not the effect of the snowfall strength countermeasure is taken, not by faithfully reproducing the actual vehicle test, but by taking into account the component structure and the design around the roof panel. That is, in the present embodiment, the vehicle body portion (upper body) is interpreted as a “base” for evaluation, the base 2 (upper body) is manufactured as a rigid body, and a miniature model of a separately manufactured roof outer panel is mounted thereon. In this case, the evaluation can be easily performed.

Next, an example based on the present embodiment will be described.
The roof model 1 was produced by press molding to a 1/10 size of a roof panel of an actual vehicle. The material of the roof model 1 was the same material (iron) as the roof outer. In the present embodiment, as the roof model 1, a two-level model of a roof model A having a thickness of 0.3 mm and a roof model B having a thickness of 0.5 mm was prepared. The shape of the roof model 1 was the shape shown in FIG.
The shape of a 1/10 size of the upper body in the actual vehicle was set on the base 2, and the base 2 was manufactured with a three-dimensional printer. The base 2 was made of resin.
Then, as shown in FIG. 3, the outer peripheral side surface of the base 2 was fixed on a base made of an aluminum frame to increase rigidity. Further, a contact type displacement meter 4 was set so as to hit the lower surface of the roof model 1 from the bottom side. This makes it possible to measure the deformation of the roof model 1 that is hidden by the rubber sheet panel during the test.

Thereafter, as shown in FIG. 4, the roof model 1 was attached to the base 2, and the roof model 1 was temporarily fixed to the base 2 with tape to prevent the roof model 1 from laterally shifting.
Here, a plurality of rubber sheet panels 6 (220 g per sheet) cut out to the same size as the surface of the roof model 1 are prepared.
Then, as shown in FIG. 5, a rubber sheet panel 6 is sequentially stacked on the roof model 1 fixed to the base 2 to increase the load load in a uniform distribution. Each time the rubber sheet panel 6 was laminated, the displacement of the roof model 1 in the thickness direction was measured by the displacement meter 4.

FIG. 6 shows the measurement results. The measurement result shown in FIG. 6 is a relationship between the displacement of the roof model 1 and the snow load (the uniformly distributed load by the rubber sheet).
As can be seen from FIG. 6, the roof model B having a plate thickness of 0.5 mm has higher rigidity than the roof model A having a plate thickness of 0.3 mm, and the evaluation of the snow load based on the present invention. However, it turns out that it has been evaluated properly. Here, the roof model A and the roof model B are panels of the same shape and the same material except for the plate thickness.

Here, in FIG. 6, C is a roof model made of the same material with the same dimensions and the same material as the roof model B but different in shape from the roof model B and made of a flat plate material in the width direction (plate thickness: 0). .5 mm).
The displacement of the roof model 1 and the snow load obtained by a model such as the roof model C may be evaluated based on the evaluation level based on the degree of improvement in the snow intensity.
Note that, even if the roof model 1 has the same shape, the snow intensity changes even when the material of the roof model 1 is changed.

DESCRIPTION OF SYMBOLS 1 Roof model 2 Base 3 Restraint device 4 Displacement gauge 6 Rubber sheet panel

Claims (4)

  Prepare a roof model that is the same size as the roof panel to be evaluated or a shape in which the roof panel is reduced, and apply an evenly distributed load from above to the roof model surface while the outer periphery of the roof model is fixed to the base. And measuring a deformation amount of the roof model due to the load.   The load of the uniform distribution load is implemented by placing a rubber sheet panel having the same shape as the roof model on the roof model, and changing the applied uniform load by sequentially stacking the rubber sheet panels. 2. The simple test method for snow intensity of a vehicle according to claim 1, wherein   3. The simple snowfall strength test method for an automobile according to claim 1, wherein an upper model that is a model of an upper body constituting an upper portion of the automobile body supporting the roof panel is used as the base. The roof model has a reduced size of the roof panel,
4. The method of claim 3, wherein the upper model is manufactured using a three-dimensional printer, and the roof model is manufactured using the same metal material as the roof panel to be evaluated.

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