JP2011245506A - Step bending processing device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a step bending processing device which can perform step bending processing by one process, can improve the quality of products, and can lengthen the life of a die.SOLUTION: A parted angle α formed by an inclined plane continuous from a first corner portion to a second corner portion of a die 110 and a direction of pressure welding, and a relative shift amount δ of the die 110 and a punch 120 corresponding to the sheet thickness t of a sheet metal in the direction perpendicular to a direction of pressure welding satisfies the relations: α=25°-35° and δ=t(1-tanα)cosα. Since the parted angle is set appropriately, the decreasing of the sheet thickness of a step bending portion can be reduced; and since the shift amount is set appropriately, a thrust amount can be reduced.

Description

  The present invention relates to a step bending apparatus and method for performing step bending in the processing of a sheet metal housing or the like.

  At present, in the processing of a sheet metal housing or the like, a sheet metal is often step-bended. Therefore, by generalizing the shape of complicated step bending dies, if the die shape data and workpiece plate thickness are input to the numerical controller, the D value and stroke amount can be obtained by calculation, and the necessary step bending is performed. There has been proposed a step bending method that can be used.

  In that technique, the angles formed by the center line of the V-shaped groove of the lower mold and the left and right inclined surfaces are θ1 and θ2, and the angles formed by the center line of the mountain portion continuous to the V-groove and the inclined surfaces of the left and right are And a lower mold corresponding to the lower mold.

  In such a step bending method for plate-shaped sheet metal, any one of a plurality of corresponding inclined surfaces in the upper and lower molds is subjected to coining bending depending on the magnitude relationship of θ1, θ2, and θ3. Select the mold to be used from the upper and lower molds.

  The D value and stroke amount at the time of coining bending in the selected mold are calculated and obtained, and step bending is performed using the D value and stroke amount obtained by this calculation as control data for step bending (Patent Literature). 1).

  Further, there has been proposed a step bending method in which the most important step dimension is accurately obtained in relation to the positioning between the upper and lower tables by the control device. In this technique, a pair of punches and dies having the same shoulder radius and the same V width are used, and one of the punch and die is set to the other so that the distance between the punch and the die becomes a predetermined value. And the workpiece is step bent (Patent Document 2).

Japanese Patent Laid-Open No. 2004-114057 JP 2003-191015 A

  However, when step bending is performed, bending accuracy is varied by bending with an offset mold, which causes an increase in the defect rate.

  However, the product shape of step bending is frequently used, and it has been necessary to consider how efficient and safer the step bending process should be. Moreover, since the cost of the mold becomes expensive, it is essential that one mold can be used frequently.

  When performing step bending, it can be bent with an offset die or a step bending die with a distribution angle of 45 °, but the bending accuracy will vary and the product bending part will be damaged and the plate thickness will decrease. In addition, there was a concern that the load on the mold would increase. In addition, the number of man-hours increases in step bending by V-bending. Furthermore, the mold must be changed according to the thickness of the product.

  The present invention has been made in view of the above-described problems, and can be step-bended by a single process, can improve the quality of a product, and can extend the life of a mold. A step bending apparatus and method are provided.

The step bending apparatus of the present invention includes a die having a first corner having an inner angle of about 90 ° and a second corner having an inner angle of about 270 ° formed on the surface, and a first angle having an inner angle of about 270 °. A punch having a surface and a second corner having an inner angle of about 90 ° formed on the surface, and a pressure contact mechanism that presses the punch and the die against a sheet metal to be step-bended. And a relative shift amount δ orthogonal to the direction of pressure contact between the die and the punch corresponding to the sheet thickness t of the sheet metal, and the distribution angle α between the slope communicating with the second corner and the direction of pressure contact,
α = 25 ° -35 °
δ = t (1-tan α) cos α
Satisfied.

The step bending method of the present invention includes a die having a surface formed with a first corner having an inner angle of about 90 ° and a second corner having an inner angle of about 270 °, and a first angle having an inner angle of about 270 °. A step bending method in which a punch having a surface and a second corner having an inner angle of about 90 ° is pressed against a sheet metal and is bent from the first corner of the die to the second The distribution angle α between the slope communicating with the corner and the direction of pressure contact, and the relative shift amount δ orthogonal to the direction of pressure contact between the die and the punch corresponding to the sheet thickness t of the sheet metal,
α = 25 ° -35 °
δ = t (1-tan α) cos α
Satisfied.

  The angle referred to in the present invention means that the angle is physically formed with the angle as a target, and naturally it is not necessary to be a geometrically perfect angle.

In the step bending apparatus of the present invention, the distribution angle α between the inclined surface communicating from the first corner to the second corner of the die and the direction of press contact, and the press contact between the die and the punch corresponding to the sheet thickness t of the sheet metal. The relative shift amount δ orthogonal to the direction is
α = 25 ° -35 °
δ = t (1-tan α) cos α
Satisfied. For this reason, since the distribution angle is set appropriately, the reduction in the plate thickness of the step bending portion can be reduced, and the quality of the product can be improved. In addition, since the shift amount is set appropriately, the thrust amount can be reduced, which can extend the life of the mold.

It is a typical front view which shows the principal part of the step bending processing apparatus of embodiment of this invention. It is a typical front view which shows the whole structure of a step bending processing apparatus. It is a typical front view which shows the whole structure of a step bending processing apparatus. It is a typical front view which shows the principal part of a step bending processing apparatus. It is a typical front view which shows the principal part of a step bending processing apparatus. It is a typical front view which shows the sheet metal by which the step bending process was carried out. It is a typical front view which shows a punch.

  An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the step bending apparatus 100 of the present invention includes a die 110 having a first corner portion 111 having an inner angle of 90 ° and a second corner portion 112 having an inner angle of 270 ° formed on the surface, and an inner angle 270. A punch 120 having a first corner portion 121 of 90 ° and a second corner portion 122 having an inner angle of 90 ° formed on the surface, and a press-contact mechanism for pressing the punch 120 and the die 110 against a sheet metal to be step-bended. Have.

Then, the distribution angle α between the inclined surface communicating from the first corner portion 111 to the second corner portion 112 of the die 110 and the pressing direction, and the pressing direction of the die 110 and the punch 120 corresponding to the plate thickness t of the sheet metal MP. Relative shift amount δ orthogonal to
α = 25 ° -35 °
δ = t (1-tan α) cos α
Satisfied.

Furthermore, in the step bending apparatus 100 according to the present embodiment, as shown in FIGS. 2 and 3, the shift amount δ corresponds to the sheet thickness t of the sheet metal.
δ = t (1-tan α) cos α
And a shift mechanism 130 for relatively moving the die 110 and the punch 120 so as to satisfy the above.

The distribution angle α of the die 110 is
α = 30 °
It is.

  More specifically, in the step bending apparatus 100 according to the present embodiment, the die 110 is slidably supported by the shift mechanism 130 in a horizontal direction orthogonal to the vertical direction that is the pressure contact direction.

  The shift mechanism 130 includes a replaceable spacer 131 having various plate thicknesses and a bolt (not shown) that presses the die 110 against the spacer 131, and is fixed by sliding the die 110 in the horizontal direction. To do.

In the above-described configuration, in the step bending method by the step bending apparatus 100 of the present embodiment, first, the sheet thickness t of the sheet metal MP is set to δ = t (1-tan α) cos α.
α = 30 °
The shift amount δ is calculated by substituting into this equation.

  The position of the die 110 is determined by the calculation result. In order to set the position of the die 110, a spacer 131 having a thickness obtained by subtracting the shift amount δ from a predetermined value is set in the gap as shown in FIG. 3, and is fixed by pressing with a bolt.

  When the die 110 is set as described above, the sheet metal MP is set, the punch 120 is lowered, and step bending is performed, and the operation is completed.

In the step bending apparatus 100 of the present embodiment, as described above, it corresponds to the distribution angle α between the inclined surface communicating from the first corner to the second corner of the die 110 and the direction of pressure contact, and the sheet thickness t of the sheet metal. The relative shift amount δ orthogonal to the direction of pressure contact between the die 110 and the punch 120,
α = 25 ° -35 °
δ = t (1-tan α) cos α
Satisfied.

  For this reason, since the distribution angle is set appropriately, the reduction in the plate thickness of the step bending portion can be reduced, and the quality of the product can be improved. In addition, since the shift amount is set appropriately, the thrust amount can be reduced, which can extend the life of the mold.

  Here, the principle of the step bending apparatus 100 of the present embodiment will be described in order below. First, as shown in FIG. 4, F is a load force, 120 is a punch, and 110 is a die.

Where F1 = Ftanα
F2 = F / tanα
F3 = Ftanα
So the balance formula is F / tanα = 2Ftanα
It becomes.

  If the angle is calculated as it is, α≈35.26 °. Using this result, an experiment was conducted with α = 35 ° as the distribution angle. Moreover, this experiment was also conducted in a stepped mold having a distribution angle of 45 °, and the results of comparison are shown below.

  In this experiment, the amount of thrust and the amount of change in the thickness of the step bend were determined. Here, the thrust amount is an amount by which the punch 120 is displaced in the horizontal direction perpendicular to the pressing direction, and was measured with a dial gauge as shown in FIG. As shown in FIG. 6, the plate thickness of the step bent portion is the plate thickness of the step bent portion.

  As shown in the table above, it was found that the thrust obtained by static balance calculation can be reduced somewhat, but cannot be reduced to zero. That is, it is considered that extra dynamic thrust is added to the punch 120 from the sheet metal MP during the coining process.

  FIG. 7 shows the force that is newly applied during the coining. In order to cancel this force, a force acting newly at the time of coining, which is a variable element, was added to the static load balance equation, thereby constructing a balance of the entire external force with F2.

The balanced equation constructed at this time is F / tanα = 2Ftanα + Ctanα
It is.

  The term of C · Ftanα on the right side is the dynamic thrust force that acts newly. C is a coefficient obtained from experimental data, and C = 1.43 to 1.67. This term assumed that extra thrust force was generated at the moment of completion of pressurization based on the displacement obtained from the experimental data of the existing mold.

When α calculated from this equation is calculated,
α≈27.57 ° to 28.37 °
It becomes.

  In addition, when the value of α = 27.918 ° was calculated by another analysis method, and an experiment was actually performed using a combination mold having a distribution angle of 25 ° and 65 °, the thrust amount was 0.03 [mm]. The plate thickness was also reduced by 0.1 [mm], and it was confirmed that the step bending was completed without difficulty and improved.

  From these results, the distribution angle α, which is a familiar triangle angle in calculation and relatively easy to design, manufacture and measure, was set to 30 °. 2 and 3, the die 110 can be shifted as shown in FIG. 2 and FIG. 3, and the sheet metal MP according to the dimension determined not to determine the shift amount δ of the die 110 according to the plate thickness shown in FIG. Is not finished.

Therefore, in order to determine this shift amount, from FIG.
cosα = δ / t (1-tanα)
From δ = t (1-tanα) cosα
Δ was obtained by the following equation.

  The present invention is not limited to the present embodiment, and various modifications are allowed without departing from the scope of the present invention. For example, in the above embodiment, the punch 120 can be displaced in the vertical direction, and the die 110 can be displaced in the horizontal direction. However, the die 110 may be fixed so that the punch 120 can be displaced in the vertical and horizontal directions (not shown).

In the above embodiment, the sheet thickness t of the sheet metal MP is set to δ = t (1-tan α) cos α.
α = 30 °
The shift amount δ is calculated by substituting it into the following equation, and the die 110 is shifted by moving the shift mechanism 130 manually correspondingly. However, such a shift mechanism 130 may be NC (Numerical Control), and when the thickness t is input, the shift amount δ is automatically calculated and the die 110 may be moved (not shown). .

  Needless to say, the above-described embodiment and a plurality of modifications can be combined within a range in which the contents do not conflict with each other. Further, in the above-described embodiments and modifications, the structure of each part has been specifically described, but the structure and the like can be changed in various ways within a range that satisfies the present invention.

100 Processing Device 110 Die 111 First Corner 112 Second Corner 120 Punch 121 First Corner 122 Second Corner 130 Shift Mechanism 131 Spacer MP Sheet Metal t Plate Thickness α Angle δ Shift Amount

Claims (4)

A die having a first corner with an interior angle of about 90 ° and a second corner with an interior angle of about 270 ° formed on the surface;
A punch in which a first corner having an inner angle of about 270 ° and a second corner having an inner angle of about 90 ° are formed on the surface;
A pressure contact mechanism that presses the punch and the die against a sheet metal to be stepped;
A distribution angle α between a slope communicating from the first corner to the second corner of the die and the direction of the press contact, and a direction of the press contact between the die and the punch corresponding to a sheet thickness t of the sheet metal Relative shift amount δ orthogonal to
α = 25 ° -35 °
δ = t (1-tan α) cos α
Step bending machine that satisfies the requirements. The shift amount δ is δ = t (1−tan α) cos α corresponding to the sheet thickness t of the sheet metal.
The step bending apparatus according to claim 1, further comprising a shift mechanism that relatively moves the die and the punch so as to satisfy the above. The distribution angle α of the die is
α = 30 °
The step bending apparatus according to claim 1 or 2. A die having a first corner with an interior angle of about 90 ° and a second corner with an interior angle of about 270 ° formed on the surface, a first corner with an interior angle of about 270 ° and a first corner with an interior angle of about 90 °. It is a step bending method in which a punch formed on the surface is pressed against a sheet metal, and is step bent,
A distribution angle α between a slope communicating from the first corner to the second corner of the die and the direction of the press contact, and a direction of the press contact between the die and the punch corresponding to a sheet thickness t of the sheet metal Relative shift amount δ orthogonal to
α = 25 ° -35 °
δ = t (1-tan α) cos α
A step bending method that satisfies the requirements.

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