JP3410606B2 - Press working device and molded product thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing device used for press working and a molded product molded by the processing device.

[0002]

2. Description of the Related Art Conventionally, for example, large parts such as side panel outers and front fenders which constitute an automobile are molded by a deep drawing type press working apparatus. FIG. 7 shows this type of press working apparatus according to the prior art. That is,
The press working apparatus 10 according to the related art includes a blank holder 12, a hole portion 14 is defined in the blank holder 12, and a punch 16 is slidably inserted into the hole portion 14. The hole 14 is provided on the blank holder 12.
A groove portion 18 that surrounds and circulates is defined. The press working apparatus 10 is provided with a die 20 configured to be able to move toward and away from the blank holder 12. The die 20
Has a pressing surface 24 that abuts the blank holder 12 via the work 22, and the pressing surface 24 has a convex portion 26 that engages with the groove portion 18. The die 2
When the punch 16 enters the work 0, the work 22
A shaped portion 28 is formed to form the shape into a predetermined shape. The wall portion forming the shape portion 28 is continuously formed with the pressing surface 24 via the shoulder portion 30, and in this case, the shoulder portion 30 is formed.
Has a curved surface with a predetermined radius of curvature R.

Therefore, when the work 22 is formed by the press working apparatus 10, first, the blank holder 12 is formed.
A plate-shaped work 22 formed of a steel plate or the like is placed on the.
Next, the die 20 approaches the blank holder 12, and the predetermined portion 32a on the work 22 is clamped by the upper portion of the blank holder 12 and the clamping surface 24 of the die 20. At this time, the convex portion 26 enters the groove portion 18 side and the work 22 is deformed corresponding to the shapes of the groove portion 18 and the convex portion 26,
The work 22 is positioned. Then, as shown in FIG. 8, the punch 16 rises inside the hole 14 and presses the work 22, and the predetermined portion 32 b on the work 22 contacts the shoulder 30 of the die 20. Under the further pressing action of the punch 16, as shown in FIG. 9, the parts 32a and 32b of the work 22 flow in the direction of arrow A and are swept into the wall forming the shape part 28, and the press working is completed. To do. The pressed work 22 is cut along a cut line 34 by a cutting device (not shown) to obtain a desired press-formed product.

[0004]

By the way, in the above-mentioned conventional press working apparatus 10, when the work 22 is formed,
The part 32b abuts the shoulder portion 30, and when flowing in the arrow A direction, the extension direction (arrow A direction) and the bending direction (arrow B direction)
Plastic deformation occurs. On the other hand, in the portion 32a that is in contact with the pressing surface 24, plastic deformation occurs first in the expanding direction at the pressing surface 24 and then in the bending direction and the expanding direction at the shoulder portion 30. As described above, the work 22 has a different deformation history depending on its part, and a shock line is generated at the boundary between parts having different deformation histories, which causes a problem in that the appearance quality of the product deteriorates.

In order to remove the shock line, there is a method in which the product is drawn by deeper drawing so that the shock line is generated outside the product so that the shock line cannot be seen on the product surface. . Also, shoulder 3
There is known a method of increasing the radius of curvature R of 0 to reduce the deformation in the bending direction with respect to the work 22 and reducing the shock line. However, these methods have a problem that the yield of the works 22 decreases, and
There is a drawback that the product shape is limited.

The present invention has been made to solve the above-mentioned problems, and it is possible to reduce the shock line without lowering the yield of works, and to provide a press working apparatus which is not restricted by the product shape, and a molded product thereof. The purpose is to provide.

[0007]

In order to achieve the above-mentioned object, the present invention provides a blank holder, a punch which is relatively insertable into a hole of the blank holder, and a relative relative to the blank holder. A die that can be moved toward and away from the blank holder, the die including a pressing surface facing the blank holder, a shoulder portion formed continuously with the pressing surface, and the shoulder portion.
Includes a continuous to formed shaped portion, to said shoulder portion continuously formed by different mold curved surface of a plurality of curvatures, of the plurality of mold curved surface, wherein the mold curved surface in contact with the nip-pressing surface The radius of curvature is gradually reduced toward the molding curved surface in contact with the shape portion, and the curvature radius R _{1 of the} molding curved surface in contact with the pressing surface is
There characterized Rukoto set within the limits of elastic deformation.

According to the present invention, when the work is clamped by the blank holder and the die and the punch is relatively displaced, a predetermined portion of the work comes into contact with the pressing surface and flows from the pressing surface to the shoulder portion. . At this time, a force is applied to the portion in the bending direction, but the curvature radius R ₁ of the molding curved surface continuous to the pressing surface is elastic.
Because they are sized rather set within the limits of sexual variations, small plastic deformation of the bending direction, the shock line occurring in the work is extremely small. While the punch is further displaced, the predetermined portion of the work is sequentially moved through the plurality of forming curved surfaces to flow into the wall portion forming the shape portion and is formed, but the radius of curvature of each forming curved surface is gradually increased. The shock line is extremely small because it changes to and does not change rapidly.

In this case, the radius of curvature R ₁ of the forming curved surface in contact with the pressing surface is ε, the strain rate when the deformation due to the force in the bending direction applied to the work is the boundary between the elastic deformation and the plastic deformation, and the surface of the work. If the distance from the center line to the center line is y, then R ₁ ≧ y / ε, and the degree of plastic deformation of the work in the bending direction when the work in contact with the pressing surface flows into the forming curved surface in contact with the press surface. Becomes smaller and the shock line generated on the work becomes extremely small.

Further, the present invention is a molded product molded by a press working apparatus, comprising a plurality of curved surfaces having different curvatures formed by the shoulder portion of the die of the press working apparatus, The curved surface has a radius of curvature gradually reduced from a portion clamped by the pressing surface of the die toward a portion that is fitted and molded in the shape portion of the die ,
A curved surface formed by a molding curved surface that contacts the clamping surface of the die
The radius of curvature R ₁ of is characterized Rukoto set within the limits of elastic deformation.

According to the present invention, when a press-formed product is formed, the predetermined portion of the work which abuts against the pressing surface of the die is
Flow from the pinching surface to the shoulder. In this case, the the predetermined portion a force in the bending direction is applied, the radius of curvature R ₁ of the curved surface in contact with the pressing surface is set rather large within the limit of elastic deformation
Because there, small plastic deformation of the bending direction, the shock line occurring in the work is extremely small.

In this case, the radius of curvature R ₁ of the molding curved surface continuing to the portion held by the pressing surface of the die is such that the deformation due to the force in the bending direction applied to the work is the boundary between elastic deformation and plastic deformation. When the strain rate is ε and the distance from the surface of the work to the center line is y, R ₁ ≧ y / ε, and the work contacting the pressing surface contacts the pressing surface.
When the work flows to the forming curved surface, the work is less plastically deformed in the bending direction, and the shock line generated in the work becomes extremely small.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A press working apparatus according to the present invention and a molded article molded by the same will be described below in detail with reference to the accompanying drawings, with reference to preferred embodiments.

In FIG. 1, reference numeral 40 indicates a press working apparatus 40 according to this embodiment. The press working apparatus 40 includes a blank holder 42, a hole 43 is defined in the blank holder 42, and a punch 44 is slidably inserted into the hole 43. The blank holder 42
A groove 46 that surrounds and surrounds the hole 43 is defined in the upper part of the. The press processing device 40 is provided with a die 48 that can be moved toward and away from the blank holder 42. A clamping surface 52 is formed on the die 48 so as to contact the blank holder 42 via the workpiece 50. The clamping surface 52 has a convex portion 54 having a shape corresponding to the groove 46.
Are formed. The punch 44 enters the die 48 to shape the work 50 into a predetermined shape.
The wall portion forming the shape portion 56 is formed continuously with the pressing surface 52 and the shoulder portion 58.

As shown in FIG. 2, the shoulder portion 58 is continuous with the pressing surface 52 and has the first curved surface 6 having a predetermined radius of curvature R ₁ .
2, a second curved surface 64 continuous with the first curved surface 62 and having a radius of curvature R ₂ smaller than the radius of curvature R ₁ of the first curved surface 62, and the shape portion 56 from the second curved surface 64. The third curved surface 66 is formed so as to be continuous with the wall portion to be formed and whose radius of curvature R ₃ is smaller than the radius of curvature R ₂ of the second curved surface 64.

Next, the radius of curvature R ₁ of the first curved surface 62 will be described with reference to FIG.

When bending the work 50,
The strain rate ε of the center line 68 with respect to the inner circumference 70 of the work 50 caused by bending is the length L of the inner circumference 70 of the work 50.
₀ , and the length of the center line 68 is L ₁ , it can be obtained by ε = (L ₁ −L ₀ ) / L ₀ (1). From this equation, the ratio of the length L ₀ to the length L ₁ is L ₁ / L ₀ = 1 + ε (2)

From the principle of similarity, if the radius of curvature of the shoulder 58 is R and the distance from the inner circumference 70 of the work 50 to the center line 68, that is, half the thickness of the work 50 is y, then L ₁ / L ₀ = (R + y) / R (3) From the equations (2) and (3), (R + y) / R = 1 + ε (4), and the ratio between the radius of curvature R and the interval y is y / R = ε (5).

The value of the strain rate ε is within the range of elastic deformation, that is, the work 50 is deformed by applying a force in the bending direction,
When the range of the strain rate ε at which the work 50 returns to its original shape when the force application is stopped is ε ≦ 0.001 mm and the radius of curvature R of the shoulder 58 is calculated, the interval y is
If y = 0.4 mm, then R ≧ 400 mm from equation (5). That is, when a force in the bending direction is applied to the work 50 and the radius of curvature R ₁ of the first curved surface 62 when contacting the first curved surface 62 is 400 mm or more, the work 50 is not plastically deformed.

Therefore, the radius of curvature R ₁ of the first curved surface 62 is
R ₁ = 400 mm, and the radii of curvature R ₂ and R ₃ of the second curved surface 64 and the third curved surface 66 are the radius of curvature R of the first curved surface 62.
As gradually decrease from _{1, R 2 = 100mm, R} 3
= 20 mm.

The press working apparatus 40 according to the present embodiment is basically constructed as described above. Next, the operation thereof is related to the molded product molded by the press working apparatus 40. Described in.

First, as shown in FIG. 1, the workpiece 50 is placed on the blank holder 42. The thickness of this work 50 is 0.8 mm, that is, the interval y is y = 0.4 mm.

Next, when the die 48 approaches the blank holder 42, as shown in FIG. 2, the work 50 is clamped by the blank holder 42 and the die 48, and the groove 4 is formed.
6 is engaged with the convex portion 54, and the work 50 has the groove portion 46.
The work 50 is deformed so as to fit into the blank holder 42 and the die 48 and positioned. At this time,
A portion on the work 50 that contacts the pressing surface 52 of the die 48 is designated as 72a.

Then, when the punch 44 moves up, the work 50 is pressed and deformed in the direction of the arrow C and abuts on the first curved surface 62, as shown in FIG. At this time, the first curved surface 62
The portion on the workpiece 50 that abuts on is designated as 72b. Since the radius of curvature R ₁ of the first curved surface 62 is within the limit of elastic deformation, the work 50 is not plastically deformed.

When the punch 44 further rises, the work 5
0 flows in the direction of arrow D, and the part 72a of the work 50 moves on the pressing surface 52 and the part 72b moves on the first curved surface 62. Therefore, a force is applied to the portion 72a in the extension direction (arrow E direction), and the portion 72a is plastically deformed. On the other hand, a force is applied to the portion 72b in the extension direction (arrow D direction) and the bending direction (arrow C direction), but since the radius of curvature R ₁ of the first curved surface 62 is within the elastic deformation range, it is applied to the portion 72b. The plastic deformation that occurs is only due to the force in the extension direction, as in the case of the portion 72a.

When the part 72a of the work 50 moves from the pressing surface 52 to the first curved surface 62, the work 50 contacts the second curved surface 64 as shown in FIG. The portion that contacts the second curved surface 64 is 72c. At this time,
A force in the extension direction (arrow E direction) and a force in the bending direction (arrow C direction) are applied to the portion 72a, but like the portion 72b, the plastic deformation applied to the portion 72a is in the extension direction (arrow E direction). ). Therefore, since the parts 72b and 72a are plastically deformed by substantially the same force, no shock line is formed at the boundary between the parts 72a and 72b (point F in the figure).

Further, the portion 72b extends from the first curved surface 62 to the second curved surface 62.
The portion 72b moves to the curved surface 64 and is deformed by the force in the bending direction (arrow C direction). Since the radius of curvature R ₂ of the second curved surface 64 exceeds the range of elastic deformation, the portion 72b is plastically deformed in the bending direction. However, the first curved surface 6
Curvature of 2 radii R ₁ and to change sequentially the radius of curvature R ₂ of the second curved surface 64, bending direction applied to the second curved surface 64 on the workpiece 50 in the region 72c contacting with the site 72b (arrow C) The difference in force between the two is small, and therefore, the shock line generated at the boundary between the parts 72b and 72c (point G in the figure) is extremely small, which poses no problem in appearance.

Similarly, the portion 7 that abuts on the third curved surface 66.
The difference between the force in the bending direction (direction of arrow I) applied to 2d and the portion 72c is small, and the shock line generated at the boundary between the portion 72c and the portion 72d (point H in the figure) is extremely small.

When the punch 44 moves up to a predetermined position, the work 50 is set on the wall portion forming the shape portion 56, as shown in FIG. The work 50 pressed as described above is cut along a cut line 74 by a cutting device (not shown) to obtain a molded product 76.

The molded product 76 includes the first to third curved surfaces 62,
Multiple curved surfaces corresponding to 64 and 66 are formed,
Rate radius R₁~ R₃Is R₁= 400 mm, R₂= 100
mm, R₃= 20 mm, and the diameter is gradually reduced. And
The shape of this molded product 76 has a large degree of freedom in design,
Radius of curvature R of the first to third curved surfaces 62, 64, 66₁~ R ₃
To obtain a molded product 76 having a desired shape.
You can

[0031]

According to the press working apparatus and the molded product thereof according to the present invention, the following effects and advantages can be obtained.

The die has a molding surface having a large radius of curvature of a curved surface continuous with the pressing surface. Therefore, the force in the bending direction applied to the work is small, and the radius of curvature of the other forming curved surface continuous to the curved surface is gradually changed to be small, so that the shock line formed on the work can be made extremely small. Therefore, there is no problem in appearance. Further, since the degree of freedom in design is large, there is no restriction on the shape of the product and it is not necessary to squeeze deeper, so that the yield of works does not decrease.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view showing a press working apparatus according to an embodiment of the present invention.

FIG. 2 is a partially enlarged sectional view of the press working apparatus of FIG.

FIG. 3 is a partially enlarged sectional schematic explanatory view showing a curved surface of the press working apparatus of FIG.

FIG. 4 is a partially enlarged cross-sectional view showing a method of using the press working apparatus of FIG. 1 and showing a state where a work is in contact with the first curved surface.

FIG. 5 is a partially enlarged cross-sectional view showing a method of using the press working apparatus of FIG. 1 and showing a state where the work is in contact with the second curved surface.

FIG. 6 is a partially enlarged cross-sectional view showing a method of using the press working apparatus of FIG. 1 in a state where press working is completed.

FIG. 7 is a partially enlarged sectional view of a press working apparatus according to a conventional technique.

FIG. 8 is a partially enlarged cross-sectional view showing a method of using the press working apparatus of FIG. 7 and showing a state where a work is in contact with a shoulder portion.

FIG. 9 is a partially enlarged cross-sectional view showing a method of using the press working apparatus of FIG. 7 and showing a state where press working is completed.

[Explanation of symbols]

40 ... Pressing device 42 ... Blank holder 44 ... Punch 48 ... Die 50 ... Work 52 ... Clamping surface 58 ... Shoulder 62, 64, 66 ...
Curved surface 76 ... Molded product R ₁ , R ₂ , R ₃ ...
curvature radius

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) B21D 24/00 B21D 22/26

Claims (4)

(57) [Claims] 1. A blank holder, a punch that is relatively insertable into a hole of the blank holder, and a die that is relatively movable toward and away from the blank holder, the die being the blank holder. and pressing surfaces opposed to said shoulder portion formed continuously to the pressing surfaces, and a continuous and formed shape portion to the shoulder portion, the shoulder portion is different mold curved surface of a plurality of curvatures by continuously formed, among the plurality of mold curved surface, said sequential curvature radius from mold curved surface in contact with the pressing surface toward the mold curved surface in contact with the shaped portion is reduced in diameter, formed in contact with the nip-pressing surface
Stamping device of curvature radius R ₁ form curved surface, characterized in Rukoto set within the limits of elastic deformation. 2. The press working apparatus according to claim 1, wherein the radius of curvature R ₁ of the forming curved surface in contact with the pressing surface is such that the deformation due to the force in the bending direction applied to the work is a boundary between elastic deformation and plastic deformation. The press working apparatus is characterized in that R ₁ ≧ y / ε, where ε is the strain rate and y is the distance from the surface of the work to the center line. 3. A molded product formed by a press working apparatus, comprising a plurality of curved surfaces having different curvatures formed by shoulders of a die of the press working apparatus, wherein the plurality of formed curved surfaces are the die. Forming radius of curvature is gradually reduced from the portion clamped by the pressing surface of the die toward the portion that is swaged into the shape of the die to be molded and contacts the pressing surface of the die.
The radius of curvature R _{1 of} the curved surface formed by the surfaces is
Press-molded product, characterized in Rukoto set within the limits. 4. The press-formed product according to claim 3, wherein the radius of curvature R ₁ of the molding curved surface continuous to the portion clamped by the clamping surface of the die is deformed by the force in the bending direction applied to the work. The strain rate at the boundary between elastic deformation and plastic deformation is ε, and the distance from the surface of the work to the center line is y.
Then, R ₁ ≧ y / ε, which is a press-formed product.