JP7111066B2 - Method for predicting uneven position, method for predicting panel transport rigidity, and method for changing panel shape - Google Patents

Description

The present invention relates to a bump position prediction method for simply predicting the bump position of a panel, a panel transport rigidity prediction method and a panel shape changing method using the bump position prediction method.

Automobile panel parts include outer panels such as roofs, hoods, and doors, and inner panels such as floors and dash lowers. Such panel components (hereinafter also simply referred to as panels) are a group of components with a large projected area. For this reason, the panel component is much lighter than other frame components due to the reduction in plate thickness.
However, for example, when the thickness of the outer panel is reduced, in addition to the deterioration of vehicle performance (strength, rigidity, sound insulation, etc.), there is a problem that the handling of the molded panel during manufacturing becomes difficult.

Specifically, in press molding, when the panel component is transported to the press machine in the next process, the panel component is sucked and suspended by the suction cups and transported. At this time, the panel component may become uneven due to the load generated when the panel component is picked up and lifted, or when the panel transport starts or stops. When unevenness occurs, plastic deformation (permanent deformation) occurs in the panel parts, which does not satisfy the surface accuracy of the panel parts as a product, and causes a defect that necessitates the disposal of the panel parts. There is
Conventionally, it has been considered effective to reduce the transport speed of panel components in order to avoid the above problems. However, lowering the transport speed of panel parts leads to a decrease in productivity, and there is a possibility that the required number of production units cannot be achieved.

Here, the stickiness of the panel can be evaluated using the so-called "tensile rigidity" as an index. The tension stiffness represents the strength against being flattened or dented, and is a type of panel stiffness. At the position of the panel surface where the tension rigidity is weak (low tension rigidity), the sensation when touched by a person's hand deteriorates (it looks cheap and bumpy), and the bumpiness that occurs when wiping while holding down the panel when applying wax. evoke a feeling. For example, the methods described in Patent Documents 1 to 5 are available as countermeasures by predicting them in advance.
In Patent Document 1, as a method of prediction at the design stage (at the stage where there is only a drawing) before a prototype vehicle, the panel is divided into a large number of areas, and the load is sequentially applied to each area. Displaying strength distribution is described. However, in the method described in Patent Document 1, unevenness must be defined from the slope of the load-displacement curve at each point, and data at all analysis points must be inspected. This poses a problem that the number of man-hours becomes enormous. Moreover, with the method described in Patent Document 1, it is difficult to detect unevenness at points other than the load application point.

In addition, Patent Documents 2 and 3 disclose a method of obtaining a high-rigidity panel by attaching two steel plates with different high Young's modulus directions as a method for improving tension rigidity. A method of obtaining a highly rigid panel by defining the respective curvature radii in a panel having curvatures in two directions is described.
Further, Patent Documents 4 and 5 disclose a method of improving the tension rigidity by imparting a rectangular embossed shape or a bead shape with a trapezoidal cross section to a panel component constituting an outer panel. However, in the methods of Patent Documents 4 and 5, since there is no method for predicting unevenness during panel transport in advance, the problem remains that the presence or absence of problems cannot be confirmed unless the product is actually manufactured. . Therefore, it is desired to reduce the time loss in the development process and the production preparation process.

Japanese Patent No. 5915036 Japanese Patent No. 5391997 JP 2010-280127 A Japanese Patent No. 6074900 JP 2010-183939 A

As skin panels become thinner, the rigidity of the panel during press molding decreases, and the molded panel tends to become sticky during transportation in the press process. If permanent deformation occurs due to sticking, the panel must be discarded, resulting in loss. Conventionally, countermeasures have been taken to reduce the transport speed (transport slowly), but this slows down the production speed, resulting in a loss of time such as a decrease in the number of products produced.
The present invention has been made by paying attention to the above-mentioned points. It is possible to easily predict the presence or absence of unevenness during press transportation from panel shape information, and study countermeasures against the occurrence of unevenness during transportation at the part design stage. The purpose is to enable

In order to easily predict sagging during panel transport, the inventor conducted a simple load-loading simulation of the deflection behavior when a load is applied to the central part of the panel for panels that are prone to sagging and panels that do not. investigated in more detail. From the examination, it was found that, in the case of the occurrence of sticking, the sticking usually occurs in the central part of the panel, but the sticking occurs in other areas where no load is applied. Based on this finding, the inventors conceived the present invention.

To solve the problem, one aspect of the present invention is a bump position prediction method for estimating the bump position of a panel component, wherein a load is applied to a preset load application position to displace the front surface of the panel toward the back surface. The tension stiffness distribution along the panel surface, which is generated by increasing the load, is obtained multiple times by changing the amount of displacement due to the load, and from the multiple tension stiffness distributions obtained above, the sagging position on the panel surface is estimated. The gist is to

Another aspect of the present invention is a method for predicting the transport stiffness of a panel component, which is the stiffness when the panel surface is adsorbed by an adsorbing means and transported, the method estimating a sticking position. As the panel shape, the product shape of the panel component or the panel shape immediately before transportation is set, the unevenness position is estimated by the unevenness position prediction method according to claim 1, and the estimated unevenness occurrence location and the adsorption means. The gist of the present invention is to predict whether or not stickiness will occur during the transport based on the suction position. The bump position prediction method is performed, for example, by simulation analysis.

According to the aspect of the present invention, since it is possible to easily predict the unevenness of the panel, it is possible to predict the unevenness of the panel at the development stage of the vehicle. It is possible to easily predict the presence or absence of unevenness of the panel. As a result, it becomes possible to examine countermeasures against the occurrence of unevenness during transportation at the part design stage. In addition, according to this aspect of the present invention, for example, it is possible to reduce losses in new vehicle development, and to achieve efficient development and production without lowering the production speed even in mass production.

It is a figure explaining the process which concerns on embodiment based on this invention. It is a top view which shows a load application position. It is a figure explaining unevenness determination. It is a top view which shows the panel shape in an Example. It is sectional drawing of the L direction. It is sectional drawing of the W direction, (a) is model no. In the case of 1 and 2, (b) is model no. Cases 3 and 4 are shown. It is a top view which shows the restraint position of a panel, and a load position. Model no. 1 is a diagram showing tension stiffness distribution in the case of 1. FIG. Model no. 2 is a diagram showing tension stiffness distribution in case 2. FIG. Model no. 3 is a diagram showing tension stiffness distribution in case 3. FIG. Model no. 4 is a diagram showing tension stiffness distribution in the case of No. 4. FIG. Model no. 2 is a load-displacement graph for cases 1 and 2; Model no. 4 is a load-displacement graph for cases 3 and 4;

Next, embodiments of the present invention will be described with reference to the drawings.
<Configuration>
As shown in FIG. 1, this embodiment has a bump position predictor 20, a panel transport rigidity predictor 30, and a panel shape changer 40. FIG.
The unevenness position prediction unit 20 performs a process of estimating the unevenness position of the panel component formed of the evaluation panel shape 10, which is a preset panel shape. The bump position prediction unit 20 has a tension stiffness strength distribution acquisition unit 20A and a bump position evaluation unit 20B.

The tension stiffness strength distribution acquisition unit 20A applies a load from the front surface of the panel to the rear surface with respect to the load application position set in advance on the panel surface with respect to the evaluation panel shape 10 of the set panel component, so that the panel front surface is placed on the rear surface side. , the tension stiffness distribution along the panel surface generated by displacing by a preset displacement amount is obtained. Two or more levels of displacement amount are set as the displacement amounts set above, and the unevenness position prediction unit 20 obtains the distribution of tension stiffness along the panel surface for each displacement amount.
The tension stiffness distribution acquisition unit 20A obtains the tension stiffness distribution (tensile stiffness strength distribution) by load simulation.

The load load simulation is performed, for example, under the condition that the outer peripheral portion of the panel component having the evaluation panel shape 10 is restrained. For example, by dividing the panel surface into multiple areas (nodes) and applying a load to the loading point, the reaction force (load) generated in each area is calculated by simulation, and the tension stiffness along the panel surface is calculated. Obtained as a distribution (strength distribution of tension stiffness). In addition, a load-displacement curve (load distribution) in each region (node) is obtained from the tension stiffness distribution (strength distribution of tension stiffness) in a plurality of layers due to a plurality of displacement amounts.

The load application position is set at a position in the panel shape 1 where the tensional rigidity is estimated to be the weakest. In this embodiment, as shown in FIG. 2, the central portion LDA of the panel surface is the load application point. The central portion LDA of the panel surface includes, for example, the central point LD (for example, the center of gravity) of the panel and is within a radius of 10 mm from the central point LD. Vehicle panels usually have dimensions of 1 m or more in both length and width. The larger the panel area, the easier it is for unevenness to occur. In addition, in FIG. 2, the symbol H indicates an example of the evaluation position.

In addition, as the amount of displacement of the panel at the load point position, for example, two or more displacement amounts (two levels, preferably three levels or more) are set from 10 mm or more and 20 mm or less, and each simulation for obtaining the tension stiffness distribution to implement. Here, the reason why the amount of displacement is set to 10 mm or more and 20 mm or less is to deal with unevenness that may occur due to pressing in this range. There is no problem if the level of the amount of displacement is 10 levels or less, preferably 5 levels or less.
Based on the plurality of tension stiffness distributions obtained by the unevenness position prediction unit 20, the unevenness position evaluation unit 20B determines whether or not there is an unevenness location, and if there is an unevenness, determines the unevenness location.

Here, since the panel central part LDA is farthest from the restraint point on the outer periphery of the panel, it is estimated that the rigidity is the weakest. If there is a region (lower load region) where the load is lower than the panel center LDA, the unevenness position evaluation unit 20B, based on the strength of the load distribution (tensile stiffness distribution) generated by the load applied to the panel center LDA, The area is determined to be a bumpy position with a high risk of occurrence of bumpiness. Alternatively, a position where the load temporarily decreases as the displacement increases at the load application position is determined as the uneven position.
Here, when a load is applied to the central part LDA of the panel, which is presumed to have weak tensile rigidity, the tension propagates along the surface due to the load, and a bending node occurs when the load is applied, and the node is attached to the surface. However, it is presumed that the movement of the joint becomes easier when it is applied to the lower load area, and it becomes easy to become sticky.

That is, with respect to the evaluation position H, a portion of the load-displacement curve (load distribution) as shown in FIG. . Alternatively, a region where the load is lower than the panel central portion LDA, which is estimated to have weak tensional rigidity, is determined as the sticking position. In FIG. 3, the horizontal axis indicates the amount of displacement at the position where the load is applied, and the vertical axis indicates the load (tensile stiffness) as a reaction force against the load applied at the position to be evaluated. In FIG. 3, points A and B are used as measurement points for each amount of displacement when a load is applied at the evaluation position H. As shown in FIG. In this case, since point B is lower than point A, it is determined that unevenness may occur at this evaluation position. The dashed line is a graph of load change with displacement change, and if the load drop position can be detected with an increase in displacement in this graph, it is not necessary to take the displacement amount continuously from 0. In the range of 10 mm to 20 mm, if there are usually 2 or 3 points of data, it is considered possible to determine the presence or absence of unevenness.

On the other hand, if there is no low load region, it is determined that there is no unevenness on the panel.
Through the above processing, the unevenness position evaluation unit 20B determines whether or not there is an unevenness position, and if there is an unevenness, obtains the unevenness position (lower load area).
Here, in this embodiment, as the evaluation panel shape 10, the product shape of the formed panel or the panel shape immediately before transportation is set.

The panel transport rigidity prediction unit 30 acquires the unevenness position obtained by the unevenness position estimation unit 20 and the adsorption position information when the panel is adsorbed and transported by an adsorption means (for example, a suction cup) between each process. , based on the acquired information, it is determined whether or not the panel is uneven during transport.
When the suction position overlaps with the unevenness position obtained by the unevenness position estimation section 20, the panel transportation rigidity prediction section 30 determines that there is unevenness and that the panel transportation rigidity is low. On the other hand, if the suction position does not overlap the unevenness position obtained by the unevenness position prediction unit 20, it is determined that the panel rigidity is high.

The panel shape changing unit 40 performs processing when the panel conveying rigidity prediction unit 30 determines that the panel conveying rigidity is low. The panel shape changing section 40 changes the evaluation panel shape 10 so as to increase the transport rigidity of the panel.
Here, as countermeasures for changing the evaluation panel shape 10 so as to increase the transport rigidity of the panel, there are, for example, changes in the curvature of the panel, attachment of reinforcing sheets, etc., which are described in known methods, existing patent publications, publication publications, etc. Forming such as attachment, beading, etc. may be applied. Here, at the part design stage (when there is no mold), the panel shape itself is changed. If it is in the prototype stage, the mold is adjusted (adjustment of expected mold shape, etc.) according to the changed panel shape.

After the panel shape is changed by the panel shape changing section 40, the process of the unevenness position prediction section 20 is executed again to evaluate the unevenness position again. Then, when it is determined that there is an uneven position, the processing of the panel transport rigidity prediction unit 30 is performed again. When it is determined in the processing of the panel transport stiffness prediction unit 30 that the panel transport stiffness is low, the processing of the panel shape changing unit 40 is performed.
That is, the above-described processing is repeated until it is determined that there is no uneven position and that the panel transport rigidity is high.

<Other effects>
In the past, if a problem occurred after a prototype was made, the mold would be corrected through trial and error. On the other hand, in the present embodiment, it is possible to suppress the occurrence of defects at the actual product evaluation stage and contribute to reducing the development man-hour loss by examining them on the simulation.
In the above description, the case where it is implemented for the purpose of improving the panel transport rigidity is exemplified. The panel shape changing unit 40 is not limited to the panel transport rigidity, and the tension rigidity is improved so that the bump position is reduced for the low load region determined to be the bump position by the processing of the bump position prediction unit 20. It is also possible to change the panel shape so as to do so.

As described above, this embodiment is mainly used for press-formed panels having a large area and a large radius of curvature, such as exterior panels of automobiles such as roofs, hoods, and doors. It is possible to predict in advance the occurrence of distortion (permanent deformation) due to unevenness of the panel and to take countermeasures. As a result, in this embodiment, it is possible to detect the risk of unevenness before making a prototype of an actual vehicle, so it is possible to minimize losses in development and preparation for production.

That is, according to the present embodiment, since it is possible to easily predict the unevenness of the panel, it is possible to predict the unevenness of the panel at the development stage of the vehicle. It is possible to easily predict the presence or absence of sagging of the panel, which is likely to occur, and to make it possible to examine countermeasures against the occurrence of sagging during transportation at the part design stage. As a result, according to the aspect of the present invention, for example, it is possible to reduce losses in new vehicle development, and realize efficient development and production without lowering the production speed even in mass production.

(1) The bump position prediction unit of the present embodiment is a bump position prediction method for estimating the bump position of a panel component having an evaluation panel shape 10 that is a preset panel shape. The distribution of tension stiffness along the panel surface, which is generated by displacing the panel to the back side by applying a load from the front surface to the back surface of the panel at the position where the load is applied, is calculated by changing the amount of displacement caused by the load. This is obtained a plurality of times, and the unevenness position on the panel surface is estimated from the plurality of tension stiffness distributions obtained above.
Conventionally, the presence or absence of unevenness has been measured by individually applying a load to each determination region. On the other hand, in the present embodiment, when a load is applied only at a specific position, the strength distribution of the tension stiffness along the panel surface is obtained to predict the position of the unevenness. Therefore, it is possible to more easily estimate the unevenness position.

(2) With the central portion LDA of the panel surface as the load application position, the area where the tensional rigidity becomes weaker due to an increase in the amount of displacement or the area where the tensional rigidity is weaker than the load application position is estimated as the sagging position.
According to this configuration, it is possible to more reliably estimate the tensional rigidity of each region by applying a load to the position where the tensional rigidity is estimated to be the weakest.

(3) The present embodiment is a method for predicting the transport stiffness of a panel component transported while the panel surface is adsorbed by an adsorption means. The shape of the immediately preceding molded panel is set, the position of the unevenness is estimated by the unevenness position prediction unit, and whether or not unevenness will occur during transportation is predicted based on the estimated location of occurrence of unevenness and the adsorption position of the adsorption means.
According to this configuration, it is possible to evaluate in advance whether or not unevenness occurs when the panel is conveyed, and it is possible to increase the conveyance rigidity of the panel in advance. This increases the panel conveying speed accordingly, leading to improved productivity.

(4) In the present embodiment, when the panel transportation rigidity prediction unit 30 predicts that the molded panel will be uneven during panel transportation, the evaluation panel shape 10 is changed so that the transportation rigidity of the molded panel is increased. For the evaluation panel shape 10 after the change, the panel conveyance rigidity prediction unit 30 again predicts the presence or absence of unevenness.
By performing this process, it is possible to increase the panel transport rigidity.

(5) When the unevenness position predicting unit 20 estimates that there is an unevenness position, the panel shape is changed so as to reduce the locations where the estimated unevenness position occurs.
With this configuration, it is possible to increase the tensional rigidity of the entire panel.

Examples of the present embodiment will be described below.
A panel shape simulating a roof outer panel (single item) as shown in FIG. 4 was set as the panel 1 of the evaluation panel shape 10 . This panel 1 was set as a CAE model of a plan view rectangular shape with dimensions of 1200 mm×2400 mm in projection. In FIG. 4, the vertical direction is the W direction (width direction), and the horizontal direction is the L direction (longitudinal direction). As shown in Table 1, this panel 1 has a curvature in the L direction fixed at R20000 (see FIG. 5), and a combination of curvatures in the W direction in four patterns. 1 to 4. The change position of the radius of curvature in the W direction is as shown in FIG. 6, and the shape is line symmetrical in the W direction. Pattern 1 in FIG. 6(a) corresponds to model No. 1 and 2, and pattern 2 in FIG. 3 and 4.

Also, the plate thickness was set to 0.65 mm in all cases.
In addition, the evaluation panel was completely constrained (translational and rotational constraints) at the positions shown in FIG. It is assumed that this is held in an inspection jig and measured.
Then, as the tensile stiffness analysis, first, the tensile stiffness distribution when a point pressing load was applied to the center of the panel was obtained by simulation analysis, as shown in FIG. In addition, in the tension stiffness distribution analysis, since the shape is symmetrical in the W direction, the tension stiffness distribution was output by analysis only for the upper half area of the panel in order to reduce the calculation time.

Three levels of 10 mm, 15 mm, and 20 mm were set as the level of displacement.
The results of distribution analysis at each level are shown in FIGS. FIG. 8 shows model no. 1 analysis results. FIG. 9 shows model no. 2 analysis results. FIG. 10 shows model no. 3 analysis results. FIG. 11 shows model no. 4 analysis results.

8 to 11 show the distribution of tension stiffness along the panel surface when the amount of displacement is 10, 15 and 20 mm, respectively. In each figure, the area surrounded by a circle is a part where the tensile rigidity is weaker than that of the central LDA. As described above, by applying a load to the center LDA, it is possible to detect a region with low tensile rigidity in a region other than the load application point.
As can be seen from FIGS. 8 to 11, model no. In 3 (see FIG. 10), the load at the panel central portion LDA was the lowest at any displacement, and sagging did not occur in actual confirmation. On the other hand, in the other models (see FIGS. 8, 9 and 11), it has been found that there is a region where the load is lower than the central LDA of the panel. It was predicted that these factors would cause unevenness, and that there would be a high possibility that distortion would occur during transport of the panel.

12 and 13 show the displacement caused in the area where the load is low (the same area as model No. 3 for model No. 3) when the load is applied by point-pressing the central part LDA of the panel. (reaction force) graph (load-displacement curve).
As can be seen from FIGS. 12 and 13, model no. In No. 3, it was confirmed that the load decreased, i.e., sagging.

10 Evaluation panel shape 20 Uneven position prediction unit 20A Tension stiffness strength distribution acquisition unit 20B Position evaluation unit 30 Panel conveyance rigidity prediction unit 40 Panel shape change unit H Evaluation position LD Center point LDA Central part

Claims (5)

An unevenness position prediction method for estimating the unevenness position of a panel part having an evaluation panel shape by CAE simulation using a computer , comprising:
The simulation includes a bump position prediction unit having a tension stiffness strength distribution acquisition unit and a bump position evaluation unit,
The tension stiffness strength distribution acquisition unit acquires a tension stiffness distribution along the panel surface generated by applying a load to a preset load application position and displacing the panel surface toward the back side for the evaluation panel shape of the set panel component . The tension stiffness distribution is obtained a plurality of times by changing the amount of displacement due to the loading of the load , and the tension stiffness strength distribution acquisition unit obtains the tension stiffness distribution by load load simulation,
The unevenness position evaluation unit performs a process of estimating the unevenness position on the panel surface from the plurality of tension stiffness distributions obtained above.
A bump position prediction method characterized by: The above load application position is the central part of the panel surface,
The unevenness position evaluation unit estimates an area where the tensional rigidity is weakened due to an increase in the displacement amount, or an area where the tensional rigidity is weaker than the load applied position, as the unevenness position .
2. The bump position prediction method according to claim 1, characterized in that: A panel conveyance rigidity prediction method for predicting the conveyance rigidity of a panel component, which is the rigidity when a panel surface is attracted by an absorption means and conveyed , by CAE simulation using a computer , comprising:
As the panel shape for estimating the uneven position, the product shape of the panel component or the panel shape immediately before transportation is set as the evaluation panel shape ,
The above simulation
A bump position prediction unit according to claim 1;
a panel conveyance rigidity prediction unit that predicts whether or not unevenness will occur during the conveyance based on the location of unevenness estimated by the unevenness position prediction unit and information on the suction position of the suction means;
A panel transport stiffness prediction method, comprising : The above simulation
When the panel transport rigidity prediction unit predicts that the panel component will be uneven during panel transport, the panel changes the shape of the evaluation panel shape for estimating the uneven position so that the transport rigidity of the panel component is increased. A shape changing unit is provided, and after the change in the panel shape changing unit, the processing of the uneven position predicting unit is performed.
4. The method for predicting panel transport stiffness according to claim 3, wherein: Execute a simulation by CAE using a computer for panel parts in the shape of an evaluation panel,
The above simulation
A bump position prediction unit according to claim 1 or claim 2,
a panel shape changing unit that changes the shape of the evaluation panel shape so that, when the uneven position prediction unit estimates that there is an uneven position, the number of locations where the estimated uneven position occurs is reduced;
A panel shape changing method comprising :

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