JP5216736B2 - Sheet metal bending product and processing method - Google Patents

Description

  The present invention relates to a bent product in which an outer bend radius of the bent product is reduced in order to improve designability in a product using a bent product of a sheet metal and a processing method thereof.

  Conventionally, in bending a sheet metal having a sheet thickness t, it is difficult to make the curvature radius ρ1 on the inside of the bend zero, so the curvature radius ρ2 on the outside of the bend is set to a value obtained by adding the sheet thickness t to the bending inside ρ1. Become. Accordingly, the bending outer radius of curvature of a normal bent product is ρ2 larger than the plate thickness t.

  However, in the case where the sheet metal bending product is used as a design product, it is desired that the curvature radius ρ2 on the outside of the curve is reduced for the purpose of improving the design property, and bending is performed using a sheet metal having a small thickness. Alternatively, the bending radius ρ2 on the outer side of the bent product, which is the outer appearance, is reduced by forming a groove on the inner side of the bent product by cutting and performing the bending process.

Japanese Patent Laid-Open No. 2003-25019

  However, when sheet metal with a small thickness is used, the strength as a design part cannot be secured sufficiently, so the number of parts such as reinforcing the inside of the bent product is increased, or the number of processing steps for molding increases. There are challenges.

  In addition, when bending is performed by forming a groove by cutting inside the bent product, it is necessary to treat chips in the cutting process, and since the deep groove cannot be processed at once, the cutting tool is reciprocated many times. Therefore, there is a problem that the processing time becomes long.

  On the other hand, in the stainless steel plate used for the design part, the surface is whitened when the deformation strain is increased, so that the design property is deteriorated. Although the deformation strain inevitably increases outside the bending center portion of the bending process, it is desired to perform local bending deformation and minimize the deformation strain region to suppress the whitening region.

  The present invention has been made in view of these points, and the object thereof is to reduce the radius of curvature ρ2 outside the bent portion while suppressing the whitening region while ensuring the strength in the bent portion of the metal plate. It is to provide a bent product with high design properties.

  The bent product of the present invention that achieves the above object, in the bent portion of the metal plate, the plate thickness on both sides of the bending line of the metal plate is thicker than the original plate thickness, forming a partial overlay, And the bending outer radius of this bending part is below the original board thickness, It is characterized by the above-mentioned.

  Alternatively, in the bent portion of the metal plate, the central thickness of the folding line of the metal plate is equal to or less than the original thickness, and local concave portions are formed on both sides of the bent line, and The bending outer radius is equal to or less than the plate thickness.

  The bent product formed by the bending method of the present invention has a high design property in which the radius of curvature ρ2 outside the bent portion is small and the whitening region is suppressed.

It is sectional drawing before the bending process of the sheet metal material with a W groove concerning one Example of this invention. It is sectional drawing after the bending process of the sheet metal material with a W groove concerning one Example of this invention. It is a cross section after the bending process of the sheet metal material with a V groove which has build-up concerning one Example of this invention. It is sectional drawing at the time of the process of the V-groove which has the overlay concerning one Example of this invention. It is sectional drawing before shaping | molding of the simultaneous shaping | molding of the U groove processing and bending process concerning one Example of this invention. It is a punch for W groove processing concerning one example of the present invention. It is a bending part enlarged view after the bending process of the sheet metal material with a W groove concerning one Example of this invention. It is a strain distribution figure in the bending part cross section after the bending process of the sheet metal material with a W groove concerning one Example of this invention. It is a figure of groove processing by cutting. It is a metal mold | die relationship diagram when processing the V-groove which has the overlay concerning one Example of this invention. It is a metal mold | die relationship diagram when processing the V-groove which has the overlay concerning one Example of this invention. It is a metal mold | die relational view when bending the V-grooved sheet metal material which has build-up concerning one Example of this invention. It is a metal mold | die relational view when bending the V-grooved sheet metal material which has build-up concerning one Example of this invention. It is explanatory drawing of the general sheet metal bending process concerning a prior art. It is explanatory drawing of the three-way frame and door of the elevator concerning one Example of this invention. It is explanatory drawing of the elevator car concerning one Example of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of an elevator pulley stand according to the present invention will be described with reference to the drawings.

  In the prior art, generally, in bending a metal plate, a sheet metal bending product 85 having a radius of curvature 81 on the inner side of the bending is formed as shown in FIG. At this time, the bending neutral line 80 is substantially the center of the sheet thickness t, the curvature radius 82 on the outer side of the bending is approximately the value obtained by adding the curvature radius 81 on the inner side and the sheet thickness t, and the curvature radius 82 on the outer side of the bending is calculated from the sheet thickness t. It is impossible to make it smaller. At this time, in the cross section of the bent sheet metal product 85, a compressive strain 84 is generated on the inner side of the bend, and a tensile strain 83 is generated on the outer side of the bend, and the tensile strain 83 is maximum on the outer surface of the bend. Become.

  Therefore, in order to make the curvature radius 82 on the outer side of the bending smaller than the thickness t, at present, a V-groove 72 is formed on the metal plate 40 using a cutting tool 71 as shown in FIG. By bending the metal plate having the V-groove 72, a bent product having a radius of curvature 82 on the outer side of the plate thickness t or less is formed. However, in the V-groove processing using this cutting tool 71, it is necessary to process the chips 73, or a deep V-groove cannot be processed at a time, so the cutting depth of the cutting tool 71 is reduced and repeated. In order to obtain a predetermined V-groove shape, there is a problem that the processing time becomes long.

  FIG. 1 shows a metal plate having a W groove 11 constituted by two concave portions 2a and 2b and a convex portion 2c between the concave portions according to the first embodiment of the present invention. FIG. 1 (a) is a metal plate before bending, and FIG. 1 (b) is a metal plate after bending. The W groove 11 is processed into the bent portion inner side 4 by a press or the like, and the groove depth is made larger than half the plate thickness t of the metal plate, so that the remaining plate thickness h of the groove recesses 2a and 2b is 0.5 ×. smaller than t. When bending is applied to the sheet metal 1 having the W groove 11, a bent product 100 having the W groove 11 at the center of the bending portion and the curvature radius R of the bending portion outer side 3 being smaller than the plate thickness t can be obtained. . The height of the convex portion 2c from the bottom of the concave portions 2a and 2b is preferably 1 to 1.5 times the plate thickness immediately below the bottom of the concave grooves 2b and 2c.

  FIG. 5 shows a punch 51 when a W groove is formed on a metal plate by pressing. This has two protrusions with a radius of curvature w at the tip of the punch 51 with respect to the punch width B, and the radius of curvature w is smaller than 0.25 × B. That is, in FIG. 5, the two convex portions are in contact with each other, but if the curvature radius w is reduced, a gap can be provided between the two convex portions.

  The feature of the bent product having the W groove 11 is that the material flow generated during the groove processing does not flow in the plate width direction of the metal plate, but flows in the thickness direction by flowing the material between the two convex portions. The material flow can be made. Thereby, it is that the distortion which arises outside a bending part can be reduced. FIG. 6 shows an enlarged view of a bent portion of a sheet metal having a W groove. When viewed locally, each of the recesses 2a and 2b has a bending center, and the bending process is performed immediately below the protruding part 2c so as not to be the bending center. The strain distribution of the bending process section is different from that of the normal bending process. .

  FIG. 7 shows a strain distribution diagram along the center 20 of the bending section in FIG. In ordinary metal plate bending without a groove, as shown in the strain distribution 55, a compressive strain is generated inside the bent portion and a tensile strain is formed outside the bent portion, and the tensile strain is maximized on the outer surface of the bent portion. Therefore, whitening due to tensile strain occurs.

  On the other hand, the bending process of the metal plate having the W groove has a strain distribution 56. On the inner side of the bent portion, there is almost no compressive strain due to the absence of metal in the groove. Even on the outer side, the absolute values of the compressive strain and tensile strain are reduced because the plate thickness is reduced at the bent portion. Further, the strain on the outer side of the bent portion from the center of the plate thickness is almost the same, and the strain on the outer surface of the bent portion can be reduced as compared with a normal bending process. This is because the bending center is located in the concave portions 2a and 2b, so that the strain is widely distributed in the surface direction and the absolute value of the strain is reduced.

  In this way, it is effective that the material flow generated when grooving is performed by pressing is not the width direction of the metal plate but the plate thickness direction.

  As a second method for exerting the above-described effect, a bending process having a V-groove 5 as shown in FIG. 2 and an overlay 7 having a plate thickness larger than the original plate thickness t on both sides of the V-groove 5 is shown. Product 100. This bent product 100 can also make the curvature radius R of the bending part outer side 3 smaller than plate | board thickness t.

  A groove processing method for forming the overlay 7 on both sides of the V-groove 5 is shown in FIGS. 9A and 9B. A metal plate 40 is placed on a die 22 having a flat surface, and a punch 21 having a tip r and a punch angle θ larger than 90 ° is applied to the plate pressing jig 23 with a pressure F applied thereto. The V-groove 5 is formed by pushing larger than t. An enlarged view of the V-groove processing at this time is shown in FIG. By applying the pressing force F in the plate thickness direction of the metal plate by the plate presser 23, the flow 32 in the plate width direction is reduced with respect to the material flow generated when the punch 21 is pushed in, and the plate thickness direction is reduced. By using the flow 31, the overlay 8 can be formed on both sides of the V groove 5.

  FIG. 10 shows a bending method of the metal plate 1 having the overlay 7 on both sides of the V groove 5. This bending process uses the bending punch 61 and the V-groove die 62 as in the conventional method, and by pressing the bending punch 61, the bent product 100 having a small curvature radius R of the outer bending portion 3 can be processed.

  Further, the radius of curvature R on the outer side of the bending process can be reduced by forming the groove on the inner side of the bending part. FIG. 4 shows a method of forming the groove on the inner side of the bending part simultaneously with the bending process of the metal plate. . The metal plate 40 is bent as usual by a punch 41 having a convex portion 43 at the tip and a punch 41 having a shape corresponding to the V-groove except for the convex portion 43 and a normal V-groove die 42. The shape of the convex portion 43 at the tip of the punch 41 at this time is transferred to the groove shape inside the bent portion, so that the material is placed in the space between the bent portion outer side of the metal plate 40 and the V-groove die 42 during bending. The radius of curvature R outside the bent portion is reduced. However, this method requires a larger processing force than a normal bending method.

  The present technology is used for a bent portion of the three-way frame 91 and the door 92 of the elevator shown in FIG. The three-way frame 91 and the door 92 are design parts, and the smaller the corner bend R, the better the design. Similarly, it is used for a bending portion of a car side plate 93 that constitutes a car 96 on which a person and a load shown in FIG. 13 are loaded. The car side plate 93 is also a design component, and the smaller the corner radius R, the smaller the gap between the adjacent side plates, and the better the design.

  INDUSTRIAL APPLICABILITY The present invention can be used for a structural product, a building product, a housing, or the like that takes into consideration design such as using a bent product having a small bending portion outer curvature radius.

DESCRIPTION OF SYMBOLS 1 ... Sheet metal in which groove was formed, 2a, 2b ... Concave part, 2c ... Convex part, 3 ... Outside bending part, 4 ... Inside bending part, 5 ... Groove part (V groove) , 7: Built-up part after bending, 8 ... Overlaid part during groove processing, 11 ... W groove, 40 ... Sheet metal material, 100 ... Bending product (bending outer curvature) Small radius).

Claims (10)

In the bent portion of the metal plate, the thickness of the central portion of the folding line of the metal plate is equal to or less than the thickness of the metal plate, and the thickness is smaller than the central portion on both sides of the central portion of the bent line. A metal plate bending product characterized by having a concave portion and an outer bending radius of the bent portion being 0.5 times or less of a plate thickness. At the bent portion of the metal plate, the thickness of the central portion of the folding line of the metal plate is equal to or less than the thickness of the metal plate, and the thickness is smaller than the central portion on both sides of the central portion of the folding line. Forming a recess;
Bending the metal plate along the W groove so that the bending outer radius of the bent portion is 0.5 times or less of the plate thickness ;
A method for bending a metal plate. In claim 2,
The depth of the said ditch | groove is 50% or more of the thickness of the said metal plate, The bending method of the metal plate characterized by the above-mentioned. In claim 2,
The metal plate bending method, wherein the height of the convex portion from the bottom of the concave groove is 1 to 1.5 times the plate thickness immediately below the bottom of the concave portion. In claim 2,
The metal plate bending method, wherein the two concave portions have the same radius of curvature, and the radius of curvature is smaller than 1/4 of the width of the W groove. In claim 2,
The method for bending a metal plate, wherein the W groove is formed by pressing. In the bent portion of the metal plate, the plate thickness of both sides of the bending line of the metal plate is thicker than the plate thickness of the other portion of the metal plate, and the bending outer radius of the bent portion is the other of the metal plate. A bent product of a metal plate, characterized in that it is less than the thickness of the part. In claim 7,
A bent product of a metal plate, wherein the thickness of both sides of the bending line is thicker than the thickness of the metal plate by forming an overlay by plastic flow. While pressing both sides of the bent portion of the metal plate, pressing the bent portion, forming a thick portion of the groove and other portions of the metal plate around the groove; and
Bending the metal plate along the formed groove;
Method of bending metal plate including   In elevators with passenger cars, doors and three-way frames,
  The metal according to any one of claims 1, 7, and 8 in any one of the passenger car, door, and three-way frame.
A bending product of a plate or a bending method according to any one of claims 2 to 6 and 9.
An elevator characterized by using a machined metal plate.

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