JP6798380B2 - Manufacturing equipment and manufacturing method for panels with character lines - Google Patents

Description

The present invention relates to a manufacturing apparatus and a manufacturing method for a panel having a character line.

In recent years, as one means for realizing a high degree of design of the exterior design of automobiles, for example, the outer panel of the vehicle body such as the door outer panel, the fender panel, the side panel, the hood outer panel, and the rear gate outer (hereinafter, "panel"). ) Is known to have a character line. In particular, it is often used to provide a character line on a panel arranged on the side surface of the vehicle body.

On the other hand, when forming a character line on a panel, it is known that line deviation occurs, which is a poor quality of the outer panel surface. Line misalignment is especially likely to occur when the character line is sharp, but in recent years, a design with a sharp character line all over the body is often adopted, so line misalignment that impairs the appearance design is caused. The situation is likely to occur. The sharp character line means that the radius of curvature of the character line is as small as 10 mm or less, or the sandwiching angle between the two surfaces forming the character line is as small as 150 ° or less.

1 (a) and 1 (b) are cross-sectional views schematically explaining the state of occurrence of line deviation when the conventional panel manufacturing apparatus 51 is used, and FIG. 1 (a) shows the initial stage of molding. , FIG. 1 (b) shows the time when molding is completed. In the example shown in FIG. 1, the character line 23 is formed by performing press working such as drawing molding or overhang molding on the blank 20 using the punch 2, the blank holder 3, and the die 54. Is generated at the molding stage of the character line 23. Specifically, first, at the initial stage of molding shown in FIG. 1A, the blank 20 has a bending habit (black circle mark in FIG. 1) which is a local and minute bending portion due to the mold contact with the tip portion of the punch 2. It occurs inevitably. The bending habit generated here is due to the difference in tension applied to the two surfaces sandwiching the character line 23 when the die 54 is subsequently lowered, from the character line 23 along the inclined surface as shown by the arrow in FIG. 1 (b). It moves to the outside and remains without disappearing even when molding is completed. The phenomenon in which the bending habit that occurs during molding of the character line 23 remains is line deviation. When line deviation occurs, it causes highlight breakage (poor quality of the outer panel surface) at the part where the line deviation occurs in the highlight surface inspection of the panel.

As such a conventional method for forming a character line, there is a press working method described in Patent Document 1. In Patent Document 1, a lining layer made of an elastic body is provided on a valley line portion of a die, and a character line is formed by lowering a punch while fixing a blank with a wrinkle presser.

Further, Patent Document 2 discloses a press working method in which a punch, a split die, and a blank holder are used to suppress line deviation during character line forming. In Patent Document 2, a part of the blank including the character line is first pressed to form the character line, and then the part other than the character line forming portion is formed while the molded portion of the character line is restrained. There is.

JP-A-2015-96271 Japanese Unexamined Patent Publication No. 2008-100240

In the press working method of Patent Document 1, similarly to the above description based on FIG. 1, a bending habit which is a local and minute bending portion is generated in the blank due to the mold contact with the punch tip portion, and then the punch is lowered. As a result, the bending habit will move from the character line. In Patent Document 1, a lining layer is provided at the valley line portion of the die, but it is difficult to sufficiently suppress the line deviation by taking measures after the bending habit has moved.

In the press working method of Patent Document 2, the remaining portion of the blank is molded with the character line restrained, but in the case of the mold of Patent Document 2, the binding force of the character line molding portion is large, so that the character line molding is performed. When molding a part other than the part, the material that passes over the character line is less likely to move. This may cause deflection or insufficient material inflow to parts other than the character line molded part. Such molding defects are particularly likely to occur when the character line has a three-dimensionally curved shape. Therefore, when manufacturing a panel having a character line, it is desirable to be able to suppress line misalignment and suppress such molding defects.

The present invention has been made in view of the above circumstances, and an object of the present invention is to suppress line deviation when manufacturing a panel having a character line, and to suppress deflection during molding and insufficient inflow of materials.

In order to suppress the occurrence of appearance defects due to line misalignment, it is conceivable that (1) the bending habit that occurs at the initial stage of molding is eliminated, or (2) the generated bending habit is not shifted. However, it is extremely difficult to geometrically eliminate the deviation of the bending habit as described in (2) above when manufacturing a large panel. As a result of diligent studies on the above problems, the present inventors have allowed the movement of the material passing over the character line to some extent when molding a part other than the character line, and then determined the shape of the bending habit part. We obtained the finding that bending habits are made difficult to see by gently converging to the design shape.

That is, the present invention that solves the above problems provides a panel that includes a punch and a die that faces the punch, and has a character line by pressing a blank that is arranged between the punch and the die. In the manufacturing apparatus for manufacturing, the die is located between the first die, the second die, the first die and the second die at a position facing the tip of the punch. The die pad is provided with a die pad provided so as to move up and down, and the die pad is formed of an elastic body, and when the die pad and the punch are close to each other to form the character line, the blank is attached to the punch tip. It is characterized by having a hardness that allows it to be deformed into a shape along the surface of the portion.

Further, in the present invention from another viewpoint, a panel having a character line is manufactured by using a punch and a die facing the punch and pressing a blank arranged between the punch and the die. The die is moved up and down between the first die, the second die, the first die and the second die at a position facing the tip of the punch. The die pad and the punch made of an elastic body are brought close to each other to form the character line on the blank, and then the molded portion of the character line is formed by the die pad and the punch. It is characterized in that the first die, the second die, and the punch are brought close to each other while being restrained to form a portion other than the molded portion of the character line.

In the present invention, since the character line is formed by a die pad made of an elastic body, the curvature of the portion returning to the original design shape from the bending habit portion of the panel becomes large, and a sudden change in curvature on the panel can be suppressed. .. As a result, the bending habit can be made difficult to see, and as a result, the line deviation can be made difficult to see. Further, when molding other parts after molding the character line, the binding force of the character line molding portion is smaller than that in the case of molding using a metal die pad, so that the character line passes over the character line. Material movement is likely to occur. Therefore, it is possible to suppress the deflection and insufficient material inflow that may occur in the portion other than the character line molded portion.

According to the present invention, it is possible to suppress line deviation when manufacturing a panel having a character line, and also to suppress deflection during molding and insufficient inflow of materials.

It is sectional drawing for schematically explaining the occurrence state of line deviation at the time of the conventional press working, FIG. 1 (a) shows the state at the initial stage of molding, and FIG. 1 (b) is at the time of completion of molding. Indicates the state. It is sectional drawing which shows the schematic structure of the panel manufacturing apparatus which concerns on embodiment of this invention. It is a figure which shows the manufacturing method of the panel which concerns on embodiment of this invention, FIG. 3A is a state at the initial stage of molding, FIG. 3B is a state at the middle stage of molding, and FIG. 3C is a state at the time of completion of molding. Is shown. It is a schematic diagram which shows the movement of a bending habit. It is an enlarged view of the bending habit part when the character line is formed by using the conventional panel manufacturing apparatus (metal die pad). It is an enlarged view of the bending habit part when the character line is formed by using the panel manufacturing apparatus (elastic body die pad) which concerns on embodiment of this invention. It is a figure for demonstrating the relationship between the cross section of the panel shape whose contour was measured, and the curvature. It is a figure which shows an example of the curvature (the second order coefficient of a section profile), the first order factor of curvature (the third order factor of a section profile), and the second order factor of curvature (the fourth order factor of a section profile). ..

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Further, in the present specification and the drawings, elements having substantially the same functional configuration are designated by the same reference numerals to omit duplicate description.

As shown in FIG. 2, the panel manufacturing apparatus 1 according to the present embodiment faces the punch 2, the blank holder 3 that supports the blank 20 as the work material, and the punch 2 and the blank holder 3. A movable die 4 provided above the punch 2 and the blank holder 3 is provided. The blank 20 is a metal work material and is exemplified as a steel plate, but the blank 20 is not limited to a steel plate, and may be an aluminum or aluminum alloy plate or a titanium or titanium alloy plate. Further, examples of the panel obtained by press working include an outer panel of an automobile body such as a door outer panel, a fender panel, a side panel, a hood outer panel, and a rear gate outer.

The die 4 of the present embodiment is a so-called split die, and includes a die pad 7 provided between the first die 5, the second die 6, and the first die 5 and the second die 6. ing. The first die 5, the second die 6, and the die pad 7 are configured to move up and down together as the die 4. In addition to this, the die pad 7 is configured to be able to move up and down independently of the first die 5 and the second die 6 by the die pad raising and lowering mechanism 8. Further, the die pad 7 is arranged at a position facing the tip end portion of the punch 2, and the character line 23 is formed by sandwiching the blank 20 between the punch 2 and the die pad 7.

The die pad 7 of this embodiment is formed of an elastic body. If the hardness of the die pad 7 is too soft, the blank 20 may not be formed into a desired shape. Therefore, the die pad 7 has a hardness such that the blank 20 can be deformed into a shape along the surface of the punch 2 when the character line 23 is formed by the punch 2 and the die pad 7. It is preferable to use an elastic body having a Young's modulus lower than that of the blank 20, and for example, natural rubber is used. The shore A hardness of the elastic body is preferably 20 to 80. As a result, a high line deviation suppressing effect can be stably obtained. A more preferable lower limit of Shore A hardness is 30. Further, a more preferable upper limit value of Shore A hardness is 70.

The pushing load of the die pad 7 on the blank 20 is appropriately set so that the character line 23 has a desired shape, but the pushing load of the die pad 7 is preferably 0.5 to 15 MPa. As a result, a high line deviation suppressing effect can be stably obtained. In order to further enhance the effect, it is preferable that the pushing load of the die pad 7 is 1 MPa or more. Further, in order to further enhance the effect, it is preferable that the pushing load of the die pad 7 is 10 MPa or less. Further, when the shore A hardness of the elastic body is 50 or less and the pushing load of the die pad 7 is 5 MPa or less, the effect is further enhanced. The width of the die pad 7 (the cross section shown in FIG. 2, that is, the lateral length in the cross section perpendicular to the character line 23) is preferably 40 to 80 mm.

The panel manufacturing apparatus 1 of the present embodiment is configured as described above. Next, a method of manufacturing a panel having a character line 23 using the panel manufacturing apparatus 1 will be described.

First, the die pad 7 is lowered as shown in FIG. 3A from the state where the blank 20 is sandwiched between the first die 5 and the second die 6 and the blank holder 3 as shown in FIG. After lowering the die pad 7 until the lower end of the die pad 7 contacts the blank 20, the blank holder 3 and the entire die 4 including the die pad 7 are lowered as shown in FIG. 3 (b), and the tip of the punch 2 and the die pad are lowered. The character line 23 is formed at 7. After that, the blank holder 3, the first die 5, and the second die 6 are lowered as shown in FIG. 3C while restraining the molded portion of the character line 23 by the tip portion of the punch 2 and the die pad 7. As a result, a portion of the character line 23 other than the molded portion is formed into a desired product shape.

In the above panel manufacturing method, when the die pad 7 is lowered to form the character line 23, the bending habit moves as shown in FIG. At this time, when the die pad is made of metal like the first die 5 and the second die 6, the shape of the bending habit portion is as shown in FIG. On the other hand, when the die pad 7 is formed of an elastic body as in the present embodiment, the shape of the bending habit portion is as shown in FIG.

As shown in FIGS. 5 (in the case of a metal die pad) and FIG. 6 (in the case of an elastic die pad), when the die pad 7 of the present embodiment is used, a recess with respect to the design shape of the panel is compared with the case where the metal die pad is used. The “deviation depth D” indicating the degree becomes large. It is considered that the reason why the displacement depth D is increased in this way is that the blank 20 is less likely to adhere to the mold due to the elastic deformation of the die pad 7 during molding. On the other hand, when a metal die pad is used, the curvature of the portion returning to the design shape from the recessed portion of the panel becomes small as shown in FIG. 5, and the recessed portion rapidly returns to the design shape. On the other hand, when the elastic die pad 7 is used, the curvature of the portion returning to the design shape from the recessed portion of the panel becomes large as shown in FIG. 6, and the recessed portion gently returns to the design shape. That is, by forming the character line using the die pad 7 formed of an elastic body as in the present embodiment, it is important for quantitatively evaluating the line deviation as compared with the case of using the die pad formed of metal. It is possible to reduce the peak amount H of the secondary fine coefficient of the curvature of the bending habit portion.

The quantitative evaluation of the line deviation is performed using the line deviation evaluation parameter S as disclosed in International Publication No. 2016/021685. In the calculation of the line deviation evaluation parameter S, the peak amount H of the secondary fine coefficient of the curvature of the moved bending habit and the deviation width L between the position where the peak amount H appears and the position where the R stop of the design character line appears are used. Be done. The line deviation evaluation parameter S will be described below as a supplement.

The upper view of FIG. 7 is a side view of the state of line deviation. As shown in the upper diagram of FIG. 7, a gap is formed between the design shape 25 and the actual panel shape 26 outside the R stop 24 of the character line 23, and this is seen from the surface of the panel. When you look at it, you can see that the line shift appears. In the region where the line shift occurs, a curvature distribution opposite to the curvature distribution due to the curve of the design character line occurs (curvature reversal part). That is, the curvature is reversed in the region where the line deviation occurs. In the region where the curvature is reversed, light is shaded, giving the confirmation operator the impression that line deviation has occurred. In the region where the curvature on the side where the line shift occurs is reversed, if the way of returning to the original shape from the region where the curvature is reversed gently returns, the shadow due to the line shift looks ambiguous, so the line shift The impression of is small. On the other hand, when the way of returning to the original shape suddenly returns from the region where the curvature is reversed, the shadow due to the line deviation is emphasized, so that the impression of the line deviation is large. In this way, the sensory evaluation result of the line deviation has a correlation with the way the curvature distribution returns from the region where the curvature is reversed. Then, how to return the curvature distribution can be calculated from the second-order microfunction of the curvature distribution (fourth-order microfunction of the cross-sectional profile). Therefore, it is possible to evaluate the line deviation using the peak amount H of the second-order fine coefficient of curvature (fourth-order microfunction of the cross-sectional profile).

FIG. 8 shows the curvature (secondary coefficient of cross-section profile) [mm ^-1 ], the first-order coefficient of curvature (third-order coefficient of section profile) [mm ^-2 ], and the second-order coefficient of curvature (cross section). It is a figure which shows an example of the 4th order fine coefficient of the profile) [mm ^-3 ]. The vertical axis is the curvature (secondary coefficient of cross section profile) [mm ^-1 ], the first order coefficient of curvature (third order coefficient of section profile) [mm ^-2 ], and the second order coefficient of curvature (cross section). The fourth-order fine factor of the profile) [mm ^-3 ] is shown. The horizontal axis represents the position [mm] in the direction of contour measurement by the contour measuring device.

As shown in FIG. 8, the peak 401 of the curvature appears at the position 301 where the curve of the character line is the largest (the position of the R apex of the character line). At the same position 301, the peak 402 of the second order coefficient of curvature (the fourth order coefficient of the cross-sectional profile) appears. When the line deviation occurs, as shown in FIG. 8, the peak 403 of the second-order fine coefficient of curvature (fourth-order microfunction of the cross-sectional profile) appears on the side where the line deviation occurs across the character line. Therefore, the value H [mm ^-3 ] at the peak 403 of the second-order fine coefficient (fourth-order microfunction of the cross-sectional profile) of the curvature that appears on the side where the line deviation occurs, the position 303 corresponding to the peak 403, and the design character line. The deviation width L [mm] from the R stop position 302 of is obtained. Then, the line deviation evaluation parameter is calculated based on the value H and the deviation width L. For example, the line deviation evaluation parameter S is calculated by the following formula.
Linear shift evaluation parameter S = L × │H│ ⁿ
However, n is a predetermined weight index (for example, n = 1/3).

The sensory evaluation of line deviation is based on the effect of shadows due to changes in curvature on the side where line deviation occurs (corresponding to the absolute value of H) and the effect of the size of the area where line deviation occurs (shift width L). Correspondence). Therefore, the larger the absolute value of H and the larger L, the more conspicuous the line shift is, and the worse the sensory evaluation result tends to be.

The deviation width L does not change so much whether the metal die pad or the elastic die pad 7 is used. Then, as described above, when the metal die pad is used, the peak H of the second-order fine coefficient of curvature becomes relatively large, and when the elastic die pad 7 is used, the peak of the second-order fine coefficient of curvature becomes relatively large. H becomes relatively small. That is, by molding the character line 23 using the elastic die pad 7 as in the present embodiment, the line deviation evaluation parameter S can be reduced by the difference in the peak H of the secondary fine coefficient of curvature. It will be possible. As a result, the line deviation can be made difficult to see.

Further, in the panel manufacturing apparatus 1 of the present embodiment, since the die pad 7 is formed of an elastic body, a metal die pad is formed when a portion other than the molded portion of the character line 23 is molded as shown in FIG. 3 (c). The binding force of the blank 20 becomes smaller than that of using, and the material passing on the character line is likely to move. Therefore, it is possible to suppress the deflection and insufficient material inflow that may occur in the portion of the character line 23 other than the molded portion.

In the present embodiment, the upper die of the panel manufacturing apparatus 1 is the die 4 and the lower die is the punch 2, but the upper die may be the punch 2 and the lower die may be the die 4. That is, the configuration of the panel manufacturing apparatus 1 is not particularly limited as long as the die pad 7 is formed of an elastic body and the punch 2 and the die 4 are close to each other for press working.

Although the embodiments of the present invention have been described above, the present invention is not limited to such examples. It is clear that a person skilled in the art can come up with various modifications or modifications within the scope of the technical idea described in the claims, and of course, the technical scope of the present invention also includes them. It is understood that it belongs to.

A plurality of blanks having the same shape and the same material were prepared, and a panel having a character line was manufactured by a different press working method for each blank. In this embodiment, a method of forming a character line only with a punch and a die, a method of forming a character line first with a metal die pad and then forming another part, and a method of forming a character line with a natural rubber die pad first. A method was used in which the other parts were molded after the formation of the above. Then, the line deviation evaluation parameter S of the panel obtained by press working by each method was calculated, and the degree of line deviation was evaluated in three stages from the value of the line deviation evaluation parameter S. The results are shown in Table 1 below.

As shown in Table 1, by forming the character line first with the die pad first, the peak amount of the secondary fine coefficient of curvature in the bending habit part is compared with the case where the character line is formed only with the punch and the die. It was possible to reduce the deviation width L from H. Therefore, the value of the line deviation evaluation parameter S is also reduced, and the line deviation is suppressed. On the other hand, when comparing the construction methods using the die pads, the deviation width L was about the same for both, but the peak amount H of the secondary fine coefficient of curvature was smaller when the natural rubber die pad was used. It was. Therefore, the value of the line deviation evaluation parameter S is also reduced. That is, by forming the die pad with an elastic body, it was possible to suppress line deviation during character line molding.

Next, a plurality of die pads made of urethane having different hardness were prepared, and a panel having a character line was manufactured using each die pad. In addition, a plurality of panels were manufactured by changing the pushing load when lowering the die pad. Then, the moldability of each manufactured panel was evaluated based on the line deviation parameter S, and the line deviation suppressing effect was evaluated in four stages. The results are shown in Table 2 below.

As shown in Table 2, it can be seen that the smaller the Shore A hardness and the smaller the pushing load of the die pad, the higher the line deviation suppressing effect. According to the results in Table 2, the shore A hardness of the die pad is preferably 20 to 80. This makes it possible to stably obtain a high line deviation suppressing effect. Further, the pushing load of the die pad is preferably 0.5 to 15 MPa. This makes it possible to stably obtain a high line deviation suppressing effect.

The present invention can be applied to the manufacture of panels having a character line.

1 Panel manufacturing equipment 2 Punch 3 Blank holder 4 Die 5 First die 6 Second die 7 Die pad 8 Die pad elevating mechanism 20 Blank 23 Character line 24 R Stop 25 Design shape 26 Panel shape 51 Conventional panel manufacturing equipment 54 Conventional Die H Peak of secondary fine coefficient of curvature L Deviation width S Line displacement evaluation parameter

Claims (6)

A manufacturing apparatus comprising a punch and a die facing the punch, and producing a panel having a character line by pressing a blank arranged between the punch and the die.
The die is a die pad provided so as to move up and down between the first die, the second die, and the first die and the second die at a position facing the tip of the punch. With and
The die pad is formed of an elastic body, and when the die pad and the punch are close to each other to form the character line, the blank can be deformed into a shape along the surface of the punch tip portion. A panel manufacturing device with a character line that has such hardness. The apparatus for manufacturing a panel having the character line according to claim 1, wherein the shore A hardness of the elastic body is 20 to 80. The apparatus for manufacturing a panel having a character line according to claim 1 or 2, wherein the pushing load of the die pad at the time of forming the character line is 0.5 to 15 MPa. A manufacturing method for manufacturing a panel having a character line by using a punch and a die facing the punch and pressing a blank arranged between the punch and the die.
The die is a die pad provided so as to move up and down between the first die, the second die, and the first die and the second die at a position facing the tip of the punch. With and
After the die pad made of an elastic body and the punch are brought close to each other to form the character line on the blank,
While the molding portion of the character line is restrained by the die pad and the punch, the first die, the second die, and the punch are brought close to each other to form a portion other than the molding portion of the character line. A method of manufacturing a panel having a character line. The method for manufacturing a panel having a character line according to claim 4, wherein the shore A hardness of the elastic body is 20 to 80. The method for manufacturing a panel having a character line according to claim 4 or 5, wherein the character line is formed by setting the pushing load of the die pad to 0.5 to 15 MPa.

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