JP2018158351A - Apparatus and method for manufacturing panel having character line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit a misaligned line from being formed when a panel having a character line is manufactured and inhibit deflection and shortage in a material flowing during molding.SOLUTION: A manufacturing apparatus 1 includes a punch 2 and a die 4 facing the punch 2 and performs press work of a blank 20 disposed between the punch 2 and the die 4 to form a panel having a character line 23. As the die 4, a first die 5, a second die 6, and a die pad 7, which is located between the first die 5 and the second die 6 and moves up or down at a position facing a tip part of the punch 2, are provided. The die pad 7 is formed by an elastic body.SELECTED DRAWING: Figure 3

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 the high design of the exterior design of automobiles, for example, door panel, fender panel, side panel, hood outer panel, rear gate outer panel (hereinafter referred to as “panel”). ) Is known to have a character line. In particular, it is often used to provide a character line on a panel disposed on the side of the vehicle body.

  On the other hand, when forming a character line on a panel, it is known that a line shift that is a poor quality of the outer plate surface occurs. Line misalignment is especially likely to occur when the character line is sharp, but in recent years, designs that incorporate sharp character lines throughout the body have been increasingly adopted. The situation is likely to occur. The sharp character line means that the radius of curvature of the character line is as small as, for example, 10 mm or less, or the angle between two surfaces forming the character line is as small as, for example, 150 ° or less.

  1 (a) and 1 (b) are cross-sectional views schematically illustrating the occurrence of line misalignment when a conventional panel manufacturing apparatus 51 is used, and FIG. 1 (a) shows the initial stage of molding. FIG. 1B shows the time when the molding is completed. In the example shown in FIG. 1, the character line 23 is formed by performing press working such as drawing or stretch forming on the blank 20 using the punch 2, the blank holder 3, and the die 54. Occurs in the character line 23 forming stage. More specifically, first, in the initial stage of molding shown in FIG. 1A, a bending rod (a black circle in FIG. 1) which is a local and minute bending portion is formed on the blank 20 due to the die contact with the tip of the punch 2. Inevitable. Due to the difference in tension applied to the two surfaces sandwiching the character line 23 when the die 54 is subsequently lowered, the bending wrinkles generated here follow the inclined surface from the character line 23 as shown by the arrows in FIG. It moves to the outside and remains without disappearing when the molding is completed. A phenomenon in which bending wrinkles that occur during the formation of such a character line 23 remain is line deviation. When the line deviation occurs, it causes the highlight to be broken (poor quality of the outer plate surface) at the line deviation occurrence part 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, the lining layer which consists of an elastic body is provided in the trough part of die | dye, and the character line is shape | molded by dropping a punch in the state which fixed the blank with the wrinkle presser.

  Patent Document 2 discloses a press working method that suppresses a line shift during character line forming using a punch, a split die, and a blank holder. In Patent Document 2, a part of a blank including a character line is first pressed to form a character line, and then a part other than the character line forming part is formed while the character line forming part is restrained. Yes.

Japanese Patent Laying-Open No. 2015-96271 JP 2008-100240 A

  In the press working method of Patent Document 1, as in the above description based on FIG. 1, a bending wrinkle that is a local and minute bending portion is generated in the blank due to the die contact with the punch tip portion, and then the punch descends. This will move the bend fence away from the character line. In Patent Document 1, a lining layer is provided in the valley line portion of the die. However, it is difficult to sufficiently suppress the line deviation by a countermeasure after the bending wrinkle moves.

  In the press working method of Patent Document 2, the remaining part of the blank is formed in a state where the character line is constrained. When molding a portion other than the portion, movement of the material passing over the character line is less likely to occur. This may cause deflection and insufficient material inflow in portions other than the character line forming portion. 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 suppress line misalignment and suppress such molding defects.

  This invention is made | formed in view of the said situation, and it aims at suppressing the deflection | deviation at the time of shaping | molding, and lack of material inflow, while suppressing the line shift | offset | difference at the time of manufacturing the panel which has a character line.

  In order to suppress the appearance defect due to the line deviation, it is conceivable to (1) eliminate the bending crease generated at the initial stage of molding, or (2) not to shift the generated bending crease. However, it is extremely difficult to eliminate the deviation of the bending wrinkles as in (2) geometrically when manufacturing a large panel. As a result of intensive studies on the above problems, the present inventors have allowed some movement of the material passing on the character line when forming a portion other than the character line, and then changed the shape of the bent heel portion. We have obtained the knowledge that bending folds are difficult to see by gently converging to the design shape.

  That is, the present invention that solves the above-described problem includes a panel that includes a punch and a die that faces the punch, and that has a character line by pressing a blank disposed between the punch and the die. In the manufacturing apparatus for manufacturing, the die is located at a position facing the tip of the punch between the first die, the second die, and the first die and the second die. 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 come close to each other to form the character line, the blank is formed at the tip of the punch. It is characterized by having such a hardness that it can be deformed into a shape along the surface of the part.

  According to another aspect of the present invention, a panel having a character line is manufactured by pressing a blank disposed between the punch and the die using a punch and a die facing the punch. The die is moved up and down at a position facing the tip of the punch between the first die, the second die, and the first die and the second die. And forming the character line on the blank by bringing the die pad made of an elastic body and the punch close to each other, and then forming the character line forming portion with the die pad and the punch. While restrained, the first die, the second die, and the punch are brought close to each other to form a portion other than the forming portion of the character line. It is characterized in Ukoto.

  In the present invention, since the character line is formed by the die pad made of an elastic body, the curvature of the portion of the panel that returns from the bent heel portion to the original design shape is increased, and a sudden change in curvature on the panel can be suppressed. . As a result, it is possible to make the bending wrinkles difficult to see, and as a result, it is possible to make the line deviation difficult to see. Also, when forming other parts after forming the character line, the character line forming part has less restraining force than when forming using a metal die pad, so it passes over the character line. Material movement is likely to occur. For this reason, the deflection | deviation which may arise in parts other than a character line shaping | molding part, and material inflow shortage can be suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, while suppressing the line shift | offset | difference at the time of manufacturing the panel which has a character line, the bending at the time of shaping | molding and a material inflow shortage can be suppressed.

It is sectional drawing for demonstrating the generation | occurrence | production state of the line | wire shift | offset | difference at the time of the conventional press work typically and temporally, FIG. 1 (a) shows the state of the shaping | molding initial stage, FIG. Indicates the state. It is sectional drawing which shows schematic structure of the manufacturing apparatus of the panel which concerns on embodiment of this invention. 3A and 3B are diagrams illustrating a method for manufacturing a panel according to an embodiment of the present invention, in which FIG. 3A is an initial state of molding, FIG. 3B is a middle state of molding, and FIG. 3C is a state when molding is completed. Is shown. It is a schematic diagram which shows the movement of a bending rod. It is an enlarged view of the bending ridge part at the time of forming a character line using the conventional panel manufacturing apparatus (metal die pad). It is an enlarged view of the bending ridge part at the time of forming a character line 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 by which the outline was measured, and curvature. It is a figure which shows an example of a curvature (2nd derivative of a cross-sectional profile), a primary derivative of curvature (3rd derivative of a cross-sectional profile), and a secondary differential coefficient of curvature (4th derivative of a cross-sectional profile). .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present specification and drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

  As shown in FIG. 2, the panel manufacturing apparatus 1 according to this embodiment is configured to face the punch 2, the blank holder 3 that supports the blank 20 that is a workpiece, 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 workpiece and is exemplified as a steel plate, but is not limited to a steel plate, and may be aluminum or an aluminum alloy plate, titanium or a titanium alloy plate. Moreover, as a panel obtained by press work, the outer-panel panel of the vehicle body of a motor vehicle, such as a door outer panel, a fender panel, a side panel, a hood outer panel, and a rear gate outer, is illustrated.

  The die 4 of the present embodiment is a so-called divided die, and includes a first die 5, a second die 6, and a die pad 7 provided between 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 integrally as the die 4. In addition to this, the die pad 7 is configured so that it can be lifted and lowered independently of the first die 5 and the second die 6 by the die pad lifting mechanism 8. The die pad 7 is disposed at a position facing the tip 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. For this reason, the die pad 7 has such a hardness 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, for example, natural rubber. Moreover, it is preferable that the Shore A hardness of an elastic body is 20-80. Thereby, a high line shift suppression effect can be obtained stably. A more preferred lower limit of Shore A hardness is 30. Further, a more preferable upper limit value of the Shore A hardness is 70.

  Although the indentation load with respect to the blank 20 of the die pad 7 is set suitably so that the character line 23 may become a desired shape, it is preferable that the indentation load of the die pad 7 is 0.5-15 MPa. Thereby, a high line shift suppression effect can be obtained stably. In order to further enhance the effect, the indentation load of the die pad 7 is preferably 1 MPa or more. In order to further enhance the effect, it is preferable that the indentation load of the die pad 7 be 10 MPa or less. Further, when the Shore A hardness of the elastic body is 50 or less and the indentation load of the die pad 7 is 5 MPa or less, the effect is further enhanced. Note that 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 for manufacturing a panel having the 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 the die pad 7 is lowered until the lower end of the die pad 7 comes into contact with the blank 20, the blank holder 3 and the entire die 4 including the die pad 7 are lowered as shown in FIG. 7 forms a character line 23. Thereafter, the blank holder 3, the first die 5, and the second die 6 are lowered as shown in FIG. 3 (c) while the forming portion of the character line 23 is restrained by the tip portion of the punch 2 and the die pad 7. Thereby, parts other than the molding part of the character line 23 are formed in a desired product shape.

  In the above-described panel manufacturing method, when the die pad 7 is lowered to form the character line 23, the bending rod moves as shown in FIG. At this time, when the die pad is formed of metal like the first die 5 and the second die 6, the shape of the bent ridge portion is as shown in FIG. 5. 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 saddle portion is as shown in FIG.

  As shown in FIG. 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, the dent in the design shape of the panel is compared with the case where a metal die pad is used. The “deviation depth D” indicating the degree increases. The reason why the displacement depth D becomes larger in this way is considered to be that the blank 20 is less likely to be attached to the mold due to 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 from the recessed portion of the panel to the designed shape is reduced as shown in FIG. 5, and the shape is suddenly restored from the recessed portion. On the other hand, when the elastic die pad 7 is used, as shown in FIG. 6, the curvature of the portion returning from the recessed portion of the panel to the designed shape increases, and the curved shape gradually returns from the recessed portion. That is, the character line is formed using the die pad 7 formed of an elastic body as in the present embodiment, which is important in performing quantitative evaluation of the line deviation as compared with the case of using the die pad formed of metal. It becomes possible to reduce the peak amount H of the second derivative of the curvature of the bending ridge portion.

  Note that the quantitative evaluation of the line deviation is performed using the line deviation evaluation parameter S as disclosed in International Publication No. 2016/021685. For the calculation of the line deviation evaluation parameter S, the peak amount H of the second derivative of the curvature of the bent bend and the deviation width L between the position where the peak amount H appears and the R stop position of the design character line are used. It is done. The line deviation evaluation parameter S will be described below as a supplement.

  The upper part of FIG. 7 is a view of the state of line deviation seen from the side. As illustrated 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 formed from the surface of the panel. When you look at it, a line shift appears. In the region where the line deviation occurs, a curvature distribution opposite to the curvature distribution due to the curve of the designed 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 a line shift has occurred. In the area where the curvature on the side where the line deviation occurs is reversed, if the return from the area where the curvature is reversed to the original shape slowly returns, the shadow due to the line deviation will appear ambiguous. The impression is small. On the other hand, when the return from the region where the curvature is reversed to the original shape abruptly returns, the shadow due to the line shift is emphasized, so the impression of the line shift is large. Thus, the sensory evaluation result of the line deviation has a correlation with the return of the curvature distribution from the region where the curvature is reversed. The return of the curvature distribution can be calculated from a quadratic function of the curvature distribution (a quaternary function of the cross-sectional profile). Therefore, it is possible to evaluate the line deviation by using the peak amount H of the second derivative of curvature (fourth derivative of the cross-sectional profile).

FIG. 8 shows the curvature (second derivative of the cross-sectional profile) [mm ⁻¹ ], the first derivative of curvature (the third derivative of the cross-sectional profile) [mm ⁻² ], and the second derivative of the curvature (cross section). It is a figure which shows an example of the 4th derivative of a profile) [mm ^<-3 >]. The vertical axis represents the curvature (second derivative of the cross-sectional profile) [mm ⁻¹ ], the first derivative of curvature (the third derivative of the cross-sectional profile) [mm ⁻² ], and the second derivative of the curvature (cross section). 4th derivative of profile) [mm ⁻³ ] is shown. The horizontal axis represents the position [mm] in the measurement direction of the contour by the contour measuring instrument.

As shown in FIG. 8, a curvature peak 401 appears at a position 301 where the curve of the character line is the largest (position of the R vertex of the character line). At the same position 301, a peak 402 of the second derivative of curvature (fourth derivative of the cross-sectional profile) appears. When the line deviation occurs, as shown in FIG. 8, a peak 403 of the second derivative of the curvature (fourth derivative 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 derivative of the curvature (fourth derivative of the cross-sectional profile) appearing on the side where the line deviation occurs, the position 303 corresponding to the peak 403 and the design character line A deviation width L [mm] from the R-stop position 302 is obtained. Based on the value H and the deviation width L, a line deviation evaluation parameter is calculated. For example, the line deviation evaluation parameter S is calculated by the following equation.
Line deviation evaluation parameter S = L × | H | ⁿ
Here, n is a predetermined weight index (for example, n = 1/3).

  The sensory evaluation of the line deviation is based on the influence of the shadow (corresponding to the absolute value of H) due to the change in curvature on the side where the line deviation occurs and the size of the area where the line deviation occurs (the deviation width L). Response). Therefore, the larger the absolute value of H is and the larger L is, the more noticeable line deviation is and the result of sensory evaluation tends to be worse.

  Whether the metal die pad or the elastic die pad 7 is used, the shift width L does not change so much. As described above, when the metal die pad is used, the peak H of the second derivative of curvature is relatively large, and when the elastic die pad 7 is used, the peak of the second derivative of curvature is obtained. H becomes relatively small. That is, by forming 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 of the peak H of the second derivative of curvature. It becomes possible. As a result, it is possible to make line deviation difficult to see.

  Further, in the panel manufacturing apparatus 1 according to the present embodiment, the die pad 7 is formed of an elastic body, so that a metal die pad is formed at the time of forming a portion other than the forming portion of the character line 23 as shown in FIG. The restraint force of the blank 20 is smaller than that of using and the movement of the material passing over the character line is likely to occur. For this reason, the deflection | deviation which may arise in parts other than the shaping | molding part of the character line 23, and material inflow shortage can be suppressed.

  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 approach each other and perform press working.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this example. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

  A plurality of blanks made of the same shape and the same material were prepared, and a panel having a character line was manufactured by a different pressing method for each blank. In this example, a character line is formed only with a punch and a die, a character line is first formed with a metal die pad, and then another part is formed, and a character line is first formed with a natural rubber die pad. The method of forming the other part after forming was used. And the panel deviation evaluation parameter S of the panel obtained by the press work by each construction method was calculated, and the degree of the 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, when the character line is formed first with the die pad first, compared to the case where the character line is formed with only the punch and the die, the peak amount of the second derivative of the curvature at the bending saddle portion. H and the shift width L could be reduced. For this reason, the value of the line deviation evaluation parameter S is also reduced, and the line deviation is suppressed. On the other hand, when the methods using the die pad were compared, the deviation width L was the same in both cases, but the peak amount H of the second derivative of curvature was smaller when the natural rubber die pad was used. It was. For this reason, 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 hardnesses were prepared, and a panel having a character line was manufactured using each die pad. Also, a plurality of panels were manufactured by changing the indentation load when lowering the die pad. And the moldability evaluation of each manufactured panel was performed based on the line shift | offset | difference parameter S, and the line shift suppression effect was evaluated in four steps. The results are shown in Table 2 below.

  As shown in Table 2, it can be seen that the smaller the Shore A hardness is, and the smaller the indentation load of the die pad is, the higher the effect of suppressing the line deviation. According to the results in Table 2, the Shore A hardness of the die pad is preferably 20-80. Thereby, it is possible to stably obtain a high line shift suppression effect. The indentation load of the die pad is preferably 0.5 to 15 MPa. Thereby, it is possible to stably obtain a high line shift suppression effect.

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

DESCRIPTION OF SYMBOLS 1 Panel manufacturing apparatus 2 Punch 3 Blank holder 4 Die 5 1st die 6 2nd die 7 Die pad 8 Die pad raising / lowering mechanism 20 Blank 23 Character line 24 R Stop 25 Design shape 26 Panel shape 51 Conventional panel manufacturing apparatus 54 Conventional Die H Curvature second derivative peak L Deviation width S Line deviation evaluation parameter

Claims (6)

A manufacturing apparatus for manufacturing a panel having a character line by performing punching of a blank disposed between the punch and the die, the punch and a die facing the punch,
The die is a die pad provided so as to move up and down at a position opposed to the tip of the punch between the first die, the second die, and the first die and the second die. And
The die pad is formed of an elastic body, and the blank can be deformed into a shape along the surface of the punch tip when the die pad and the punch come close to each other to form the character line. An apparatus for manufacturing a panel having a character line having such hardness.   The apparatus for manufacturing a panel having a character line according to claim 1, wherein the Shore A hardness of the elastic body is 20 to 80.   The manufacturing apparatus of the panel which has a character line of Claim 1 or 2 comprised so that the indentation load of the said die pad at the time of formation of the said character line may be set to 0.5-15 MPa. Using a punch and a die facing the punch, a manufacturing method for manufacturing a panel having a character line by pressing a blank disposed between the punch and the die,
The die is a die pad provided so as to move up and down at a position opposed to the tip of the punch between the first die, the second die, and the first die and the second die. 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,
With the die pad and the punch constraining the character line forming portion, the first die, the second die, and the punch are brought close to each other to form portions other than the character line forming portion. A method for manufacturing a panel having a character line.   The manufacturing method of the panel which has the character line of Claim 4 whose Shore A hardness of the said elastic body is 20-80.   The method for manufacturing a panel having a character line according to claim 4 or 5, wherein the character line is formed with a pressing load of the die pad of 0.5 to 15 MPa.

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